Catecholamine-containing nerve terminals of the eccrine sweat glands of macaques. The external layer of the median eminence (ELME) and the arculate nucleus of male rats were studied with the Falck-Hillarp technique and electron microscopy of aldehyde-OsO4 or KMnO4 fixed after various types of hypothalamic deafferentation experiments with the Halász knife. Special reference was paid to the monoamine systems and the results can be summarized as follows. 1. The main monoaminergic input to the ELME comes from the arcuate nucleus-periventricular area via a dorsal approach. A horizontal transection through the arcuate nucleus decreases the percentage of monoamine boutons i.e. boutons with small granular vesicles, from 31.6% in the controls to 4.4% in the lesion group, whereas only a small effect is seen after anterior (or complete) deafferentations. 2. A major input to the ELME enters the basal hypothalamus at the anterior-lateral aspects (see Réthelyi and Halász, 1970). The fibers cut after anterior deafferentations in all probability mainly come from cell bodies localized in the anterior hypothalamus or even further rostrally but some may represent NA axons ascending from the lower brain stem. 3. The degeneration course of nerve endings in the ELME both after anterior deafferentations as well as after lesions in the arcuate nucleus is rapid (within 2-3 days) and morphologically characterized by an initial aggregation of large dense cored vesicles seemingly to electron dense bodies within the boutons and probably also to a closer spacing of the small electron lucent synaptic vesicles (see Raisman, 1972). This type of degeneration seems to take place both in monoamine and non-monoamine neurons. 4. Degenerating boutons are found in the arcuate nucleus after anterior and complete deafferentations. Thus, the anterior hypothalamus may exert an "indirect" control of the pituitary gland via synapses on arcuate neurons although quantitatively the "direct" influence through the projection to the ELME is of more importance. 5. After anterior deafferentations enlarged axons containing large amounts of large dense cored vesicles and other organelles are found caudally of the cut indicating the existence of rostral projections from the medial hypothalamus.


Nerve terminals and epithelial cell variety in the human lacrimal gland. Pieces of tissue taken from three human lacrimal glands were examined electron microscopically. Secretory cells varied according to the electron density and structure of their secretion granules. Secretory cells were arbitrarily categorized as light, medium or dark based on their granule content. Acini were composed of two or all three categories of cells together with myoepithelial cells and lymphocytes. A minority ogic, sympathetic terminals. The appearance of most interstitial and all parenchymal fibres was consistent with that of cholinergic, parasympathetic terminals. Parenchymal terminals were confined to ducts, terminal tubule areas and to serous (dark) cells. A large proportion of parenchymal terminals lay adjacent to myoepithelial cells in the ducts and terminal tubule regions but terminals observed among serous cells were rarely in contact with myoepithelial cells. A possible parasympathetic control of serous secretion, granule production and duct contraction and the autonomy of mucous cells is discussed.


Projections to the median eminence and the arcuate nucleus with special reference to monoamine systems: effects of lesions. The external layer of the median eminence (ELME) and the arcuate nucleus of male rats were studied with the Falck-Hillarp technique and electron microscopy of aldehyde-OsO4 or KMnO4 fixed material after various types of hypothalamic deafferentation experiments with the Haláz knife. Special reference was paid to the monoamine systems and the results can be summarized as follows. 1. The main monoaminergic input to the ELME comes from the arcuate nucleus-periventricular area via a dorsal approach. A horizontal transection through the arcuate nucleus decreases the percentage of monoamine boutons i.e. boutons with small granular vesicles, from 31.6% in the controls to 4.4% in the lesion group, whereas only a small effect is seen after anterior (or complete) deafferentations. 2. A major input to the ELME enters the basal hypothalamus at the anterior-lateral aspects (see Réthelyi and Halsáz, 1970). The fibers cut after anterior deafferentations in all probability mainly come from cell bodies localized in the anterior hypothalamus or even further rostrally but some may represent Na axons ascending from the lower brain stem. 3. The degeneration course of nerve endings in the ELME both after anterior deafferentations as well as after lesions in the arcuate nucleus is rapid (within 2-3 days) and morphologically characterized by an initial aggregation of large dence cored vesicles seemingly to electron dense bodies within the boutons and probably also to a closer spacing of the small electron lucent synaptic vesicles (see Raisman, 1972). This type of degeneration seems to take place both in monoamine and non-monoamine neurons. 4. Degenerating boutons are found in the arcuate nucleus after anterior and complete deafferentations. Thus, the anterior hypothalamus may exert an "indirect" control of the pituitary gland via synapses on arcuate neurons although quantitavely the direct influence through the projection to the ELME is of more importance. 5. After anterior deafferentations enlarged axons containing large amounts of large dense cored vesicles and other organelles are found caudally of the cut indicating the existence of rostral projections from the medial hypothalamus.


Pigment movements in fish melanophores: morphological and physiological studies. V. Evidence for a microtubule-independent contractile system. A pressure device has been used to obtain information about the forces involved in the maintenance of the aggregated state of melanophores of the angelfish, Pterophyllum scalare. Single aggregated melanophores of isolated scales were submitted to mechanical compression with forces ranging from 50-320 mup. As a function of the gradually increasing force melanophores disperse their pigment, the degree of dispersion being proportional to the intensity of the force. When microtubules are destroyed by treatment with 0.3 mM vinblastine in KCl solution, pigment dispersion in response to the external force is similar to that observed in KCl alone. After changing the medium to NaCl solution, melanin granules remain concentrated in the cell center; the force-induced melanosome dispersion, however, is significantly enhanced. Distinctly lower forces are required to produce an expansion equivalent to that observed in KCl solution. When the medium is changed to vinblastine-KCl again, the dispersion in response to the external force resembles that obtained before NaCl treatment. Removal of Ca++ and Mg++ ions by treatment with 2 mM EDTA or EGTA in Ringer's solution containing 0.1 mM adrenalin produces a remarkable enhancement of melanosome dispersion in response to increasing external force. This effect of EDTA or EGTA is completely reversible. When the medium is changed to normal Ca++-Ringer's, the force/dispersion curve resembles that obtained before EDTA or EGTA treatment. It is concluded that a state of equilibrium exists between the external force and an opposing force produced by the melanophore. The differences in the opposing force under different experimental conditions may be due to a "contractile component". This component seems to be independent of microtubules, as indicated by vinblastine experiments. It "contracts" under aggregating stimulus and "relaxes" under dispersing stimulus. From the data presented in this paper, the order of magnitude of the pressure developed by the contractile component in the completely aggregated state was calculated as between 5-7 p/cm2 in the relaxed state and about 20 p/cm2 during contraction. These values are comparable to those observed in other nonmuscular cells.


The neurons of the first synaptic region of the optic neuropil of the firefly, Phausis splendidula l. (Coleoptera). On the basis of Golgi preparations the neuronal elements of the lamina ganglionaris (first synaptic region of the visual system) of the firefly. Phausis splendidula L., are described. Of the set of 8 retinula fibres that originate from each ommatidium of the compound eye, at least 6 terminate in the esternal plexiform layer. At least one, probably two, retinula fibres per ommatidium penetrate this layer to end in the medulla, via the first optic chiasma. Five types (m1-m5) of monopolar cells can be distinguished. Only two of these, m1 and m3 have dendritic fields limited to one column of the lamina mosaic; all other monopolar cells have larger fields of up to 45 mum diameter. m2 and m4 have various field spreads in different strata of the external plexiform layer. m5 has process in only one stratum of the external plexiform layer. Medulla-to-lamina cells with arborisations associated with only a single column of the lamina mosaic were not observed; medulla-to-lamina cells whose fields coincide with the various strata of the external plexiform layer were found, however. The present observations are briefly compared with those made on another beetle, Hoplia farinosa L. Comparisons with other species of insects, and the relationship between structure of the eye and structure of the lamina are also discussed.


Fine structural changes in the hamster pineal gland after blinding and superior cervical ganglionectomy. Pineal glands of male hamsters 8 weeks after removal of both eyes or both superior cervical ganglia and those of untreated animals were studied by electron microscopy.  In the blinded hamsters the reproductive organs were remarkably involuted, whereas the pinealocytes enlarged and were characterized by a tremendous hypertrophy of the smooth-surfaced endoplasmic reticulum, in the mesh of which some dense cored vesicles were distributed.  In constrast the pinealocytes of ganglionectomized hamsters atrophied and were noted by a large number of lysosomes and sparsity of the agranular reticulum, the testes being significantly larger than the controls.  The findings were interpreted to be compatible with the view that the pineal capability of producing antigonadal substance is augmented by blinding and is suppressed by cervical ganglionectomy due to the impairment of normal functioning of the pineal by denervation.  It is assumed that the degree of development of the smooth endoplasmic reticulum in the pinealocyte is parallel to, and reflects that of the pineal activity.  Probably the membranous organelle is involved in the elaboration of the pineal antigonadal substance.


Tubular structures associated with intracytoplasmic spirochetes. When tissues of spirochete-infected brine shrimp (Artemia salina) were examined by electron microscopy, tubular structures were often seen closely associated with intracytoplasmic spirochete profiles.  These tubules were never observed in association with spirochetes found in the haemocoeal or other extracellular spaces.  Since the trilaminar layer comprising the wall of the tubules was identical in ultrastructure to the outer envelope of the spirochete, these structures were interpreted to be finger-like extensions of the spirochete outer envelope.


Ultrastructural changes in the rat carotid body in severe haemorrhagia. Rat carotid bodies were studied electron microscopically after short-term severe hypovolaemia, which is known to induce a marked chemoreceptor activation in the carotid body.  Altogether 84 nerve-endings in the hypovolaemic rats' carotid bodies and 91 nerve-endings in the control carotid bodies were investigated.  An increased accumulation of the glomus cell granular vesicles near the synaptic specializations of the nerve-endings was observed after hypovolaemia.  Moreover, a statistically significant increase in the contacts between the nerve-ending synaptic specializations and the glomus cell granular vesicles was observed after hypovolaemia.  A suggestion was made that the glomus cells might act as modulating, probably inhibitory, interneurones, whose catecholamines are responsible for the inhibition.


Ultrastructure of the integumental melanophores of the Australian lungfish, Neoceratodus forsteri. The integumental melanophores of Australina lungfish, Neoceratodus forsteri, were examined by light and electron microscopy and found to possess essentially the same structural characteristics observed in other vertebrates. The epidermal melanophores are located in the intermediate epidermis and possess round perikarya and slender dendrites extending into nearby intercellular spaces. The dermal melanophores are found immediately below the basement membrane as well as in the deeper dermis. These cells possess flattened nuclei and dendrites running parallel to the basement membrane. Each melanophore contains numerous oval or elliptical, intensely electron-dense melanosomes, relatively large mitochondria, systems of vacuolar endoplasmic reticulum, groups of free RNP particles, and some microfilaments. Only a few, short microtubules could be demonstrated in the perinuclear cytoplasm of the dermal melanophore, while a relatively large number of late premelanosomes are found both in perikarya and dendritic processes of epidermal melanophores. These premelanosomes exhibit a particulate internal structure in cross section. Both melanosomes and premelanosomes occur singly in the cytoplasm of epidermal cells, thereby confirming the existence of the epidermal melanin unit in the lowest vertebrates thus far examined electron microscopically.


Ultrastructure of the integumental melanophores of the South Americal lungfish (Lepidosiren paradoxa) and the African lungfish (Protopterus sp.). The integumental melanophores of two genera of lungfish, Lepidosiren paradoxa and Protopterus sp. were examined by light and electron microscopy.  Both species possess both epidermal and dermal melanophores with fine structural characteristics basically similar to those of other vertebrates.  The epidermal melanophores of both species are located in the intermediate epidermis, and possess thin perikarya containing round nuclei, and slender dendrites extending into the nearby  intercellular spaces.  The dermal melanophores occur immediately beneath the basement membrane, and possess flat perikarya and dendrites running horizontally between the collagen fibers of the dermis.  The integument of both species does not possess an epidermal melanin unit or a dermal chromatophore unit.  As in other vertebrates, each melanophore contains numerous oval, electron-opaque melanosomes, relatively large mitochondria, vacuolar endoplasmic reticula, and groups of RNP particles.  Although micro filaments running randomly between other organelles occur regularly, microtubules were not demonstrated.  Premelanosomes at various stages of differentiation were best illustrated in the dermal melanophores of Protopterus, and it is concluded from the observation of their fine structure that the morphological development of lungfish melanosomes closely parallels that of higher vertebrates.  On the basis of melanophore morphology, Lepidosiren and Protopterus appear to be more closely related to each other than to Neoceratodus.


The distribution of acetylcholinesterase in the cyclostome brain. II. Myxine glutinosa. In the brain of the hagfish Myxine glutinosa the distribution of acetylcholinesterase has been studied in serial cryostat sections. High activity was found in the motor column of the brain stem, in the pars ventralis thalami and in the primordium hippocampi. In the hemispheres and the olfactory bulb the ACHE-content is low.


The ultrastructure of the sensory cells in the chemoreceptor of the ommatophore of Helix pomatia L. Most of the sensory cells found in the chemoreceptor of the ommatophore of Helix pomatia are typical bipolar cells. The chemoreceptor is deveded by a furrow into two parts; within the ventral subdivision the layer of sensory cell bodiesis thicker than in the dorsal part. According to the differentiations of the apical surface of the dendrites, it is possible to distinguish six different classes: a) dendrites with one cilium and 75 nm thick cytofila (sometimes dendrites of identical appearance posses more than one cilium); b)dendrites with several cilial and 150 nm thick cytofila; c) dendrites with several cilia, 50 nm thick cytofila, and long, striated rootlets; d) dendrites with several cilia bur without cytofila; e) dendrites with 130 nm thick cytofila but without cilia; and f) dendrites with 65 nm thick cytofila but without cilia; dendrites of this class are the only ones with a cytoplasm more electron dense than that of the surrounding supporting cells. All these dendrites are connected to the surrounding supporting cells by terminal bars, each consisting of zonula adhaerens, aonula intermedia and zonula septata. The perikarya of the sensory cells measure approximately 15 mum by 8 mum and enclose 10 mum by 6 mum large nuclei. Axons, originating from these perikarya, extend to the branches of the digital ganglion. In the distal part of this gangloin the axons come into synaptic contact with interneurons, but in our electron micrography it was not possible to coordinate processes and synapses with the corresponding neurons.


The morphology of the Limulus visual system. VI. Connectivity in the ocellus. An ocellus of the horseshoe crab, Limulus polyphemus, has been serially sectioned for light and electron microscopy, its sensory cells have been indexed, and the interconnections of a third of these traced. The ocellus contains 155 retinula cells and 26 arhabdomeric cells, which are secondary sensory neurons. Of these, 55 retinula cells constitute 7 quasi-ommatidial assemblages, each innervated by at least one and a total of 9 arhabdomeric cells. When known electrotonic coupling patterns are compared with gap-junctional connections, retinula cells sensitive to visible or ultraviolet light can be tentatively identified. Retinula cell axons contribute collaterals to a synaptic plexus, in which the arhabdomeric cells apparently do not participate.


The major ganglion in the pelvic plexus of the male rat: a histochemical and ultrastructural study. To further evaluate the role of autonomic ganglia in the regulation of pelvic visceral activity, the neural elements in the major pelvic ganglion of the male rat have been studied with histochemixal and electron microscopic techniques. The principal findings are that the ganglion is composed of cholinergic and adrenergic ganglion cells as well as small intensely fluorescent (SIF) cells. Polarity in the ganglion is indicated by clustering of small ganglion cells which stain intensely for acetylcholinesterase (AChE) along the pelvic nerve while larger cells, with weak to moderate AChE activity, collect near small branches of the hypogatrric nerve. Some cholinergic ganglion cells are enclosed by a plexus of adrenergic terminals. SIF cells appear to be in contact with both cholinergic and adrenergic cells, although many of the fluorescent beads around adrenergic neurons may be short dendrites of ganglion cells, rather than processes of SIF cells. Two types of SIF cells may be distingiosjed on the basis of size and morphology of their granulated vesicles. Afferent synapses of the cholinergic type were common on SIF cells of the large granule and small granule type. Portions of SIF cells with large granules occur within the capsule of ganglion cells. Contacts seen here were interpreted as efferent synapses from SIF cells to the dendrites of ganglion cells.


A light and electron microscopic study of myelopoietic cells in the perihepatic subcapsular region of the liver in the adult aquatic newt, Notophthalmus viridescens. The liver of the newt, Notophthalmus viridescens, consists of several incompletely separated lobes of parenchymal tissue each of which is covered by a perihepatic subcapsular region (SSR) of the myeloid tissue. This tissue contains neutrophils and eosinophils in various stages of differentiation. As neutrophils developfrom myeloblasts to late neutrophilic myelocytes, two types of granules appear. The primary granules (type of granules formed first) are more electron dense and smaller than the secondary granules (type of granules formed later). The primary granules first appear at the stage designated early neutrophilic myelocyte, and the secondary granules appear at the stage of the maturing neutrophilic myelocyte. The eosinophils present are characterized by much larger granules than those observed in neutrophils. Cells in the PSR which superficially resemble small lymphocytes are primitive stem cells that give rise to neutrophils and eosinophils. The liver PSR is invested by a visceral peritoneum of simple squamous mesothelial cells some of which are ciliated.


Osteoblasts and collagen orientation.

Osteoblasts and collagen orientation. Bone was removed from the calvaria of anaesthetized 70 g rats or freshly killed young monkeys and the fibrous periosteum dissected off the inner, formative surface under 0.15 M cacodylate buffer. The bone and undisturbed osteoblasts were fixed in 3% glutaraldehyde in the same buffer for 24 to 48 hours, critical point dried and coated with evaporated carbon and gold for scanning electron microscopy (SEM). Fields of osteoblasts were photographed and chosen cells dissected off the osteoid using a tungsten needle. The control of the dissection was made possible by the use of a system of real-time stereo tv-speed SEM. The fields were rephotographed and the orientations of the osteoblasts were compared with that of the underlying collagen fibres. 62% of all osteoblasts lay with their long axes within 15 degrees of the collagen fiber orientation below and 80% within 30 degrees. Montages of large areas of osteoblasts were also made, and then compared with ones of the same area after the cells had been stripped off on adhesive tape. In general, the orientation of the collagen tended to be the same as the cell that formed it. Collagen fibers below cells at the periphery of a domain sometimes had the orientation of the cells in the adjacent patch. It is not possible to determine whether the cells controlled the orientation of the collagen, or vice versa, from this experiment, but other SEM evidence suggests that the collagen orientation in hard tissue matrices depends on the freedom of cells to move with respect to matrix surface.


Morphometric differences in midgut epithelial cells between strains of female Aedes aegypti (L.) (Insecta, Diptera). Midgut epithelial cells of female Aedes aegypti deriving from 2 different mosquito strains were compared morphometrically. One of the 2 strains was recently isolated from nature (East Africa). The other strain is an old laboratory strain, reared under laboratory conditions for about 30 years. The quantitative morphological comparison demonstrates, that the ultrastructural composition of the midqut epithelial cells corresponds generally in both strains. It can be shown, however, that in the old strain, compared to the new strain, the organelle amount of midgut epithelial cells is significantly reduced during the first 53 days of the mosquito's life. Parallel to decreased relative volumes of organelles and reduced surface densities of membrane systems an increase in lysosome-like structures is observed. These observations are interpreted as deterioration processes, possibly due to the long rearing in the laboratory. Therefore, care should be taken in the selection of an A.aegypti strain for any quantitative morphological or physiological investigation.


Changes in parotid acinar cells accompanying salivary secretion in rats on sympathetic or parasympathetic nerve stimulation. Morphological and secretory effects of stimulating autonomic nerves have been studied in parotid glands of rats. Sympathetic stimulation evoked a slow flow of saliva which had a high concentration of amylase. After long term sympathetic stimulation secretory granules were heavily depleted from the parotid acinar cells. Parasympathetic stimulation evoked a copious flow of saliva with a low concentration of amylase. However, at high frequency stimulation the total amount of amylase secreted on parasympathetic stimulation was as great or even greater than on symphatetic stimulation, nevertheless, any loss of secretory granules from the acinar cells was very small. It is concluded that secretion of parotid acinar granules in the rat is prinicipally a sympathetic function. Secretion of fluid is more effectively produced by parasympathetic stimulation and much of the amylase in such saliva appears to have arisen from sources other than the secretory granules.


Subcommissural organ-associated neurons in fetal and neonatal rabbit. Neurons which initially lie in the basal region of the subcommissural organ (SCO) were investigated in 20 rabbit fetuses from day 15 to 30 of gestation, and in eight neonatal, 4 and 8 day old rabbits. These SCO-associated neurons, first observed on day 17 of gestation, develop into (1) a rostral mesodiencephalic nerve cell group situated in an area dorsal to the rostral-most part of the SCO and (2) a more caudal layer of single neurons extending throughout the length of the SCO. The present findings are discussed in relation to recent histochemical studies that demonstrated AChE-positive neurons in the pineal complex and subcommissural area of frogs and to recent fluorescence microscopic studies in fetal and adult rats in which a 5-HT system is known to extend from the nucleus raphe dorsalis (B7) along the SCO to the pineal stalk and habenular region. The term "SCO-associated neurons" is a purely morphological way of describing the neurons in question as the neural interconnections of these neurons are still a matter of speculation.


Energy dispersive x-ray microanalysis of neurosecretory granules of mouse pituitary on fresh air-dried tissue spreads. Electron microscopy of fresh air dried spreads of unstained posterior lobe tissue from mouse pituitary disclosed neurosecretory granules. Each granule showed a seemingly homogeneous dense core surrounded by a halo and a bounding membrane. The area between granules in the cytoplasm was relatively well preserved. The energy dispersive X-ray microanalysis revealed peaks for sulfur, chlorine and potassium in two granules. The third granule displayed peaks for phosphorus and chlorine. These elements probably contribute to the high electron density of the granules. There was no peak for calcium, in contrast to the dense bodies of human blood platelets.


Scanning electron microscopic studies of the rat incisor odontoblastema. A scanning electron microscopic technique was used to investigate the surface structure of dentinogenically active odontoblasts. Thin pieces of rat incisors were fixed, rapidly frozen, freezedried at minus 70 degrees C and fractured to expose new surfaces prior to examination in the SEM. Differences in the appearance of odontoblastic cell surfaces were seen, with the most extensive ridge formations at the distal part of the sides of the odontoblasts. The predentine area displayed a spongy structure which contrasted to the compact appearance of dentine. Results are discussed in relation to previous studies at the light microscopic and transmission electron miscroscopic levels.


Ultrastructural studies on neuromuscular contacts and the formation of junctions in the flight muscle of Antheraea polyphemus (Lep.) I. Normal adult development. The ultrastructure of neuromuscular connections on developing dorsolongitudinal flight muscles were studied in the moth Antheraea polyphemus. Undifferentiated membrane contacts between axon terminals and muscle-fiber anlagen are present in the diapause pupa. They persist during the period of nerve outgrowth, which probably provides a pathway of contact guidance. By the 4th day of adult development some of these contact areas have differentiated into structures similar to neuromuscular junctions although differentiation of muscle structure does not start earlier than the eighth day. Dense-cored vesicles are abundant in many axon terminals at the beginning of development. They later decrease in number quite rapidly. The significance of the above-mentioned early junctions, their possible mode of action and the role of the dense-cored vesicles are discussed. It is proposed that they exercise a stimulating (trophic) influence on the growth of the undifferentiated muscular tissue. The imaginal neuromuscular junctions are formed during the second half of adult development. Clusters of vesicles and electron-dense depositions along the inner face of the axo- and lemma seem to initiate junction formation. Glial processes then grow between the axo- and sarcolemma and divide the large contact area into several small segments. Mutual invaginations and protrusions of the sarcolemma and the glial cell membrane subsequently form an extensive "rete synapticum." Six days before eclosion the glial and sarcoplasmic parts of the rete synapticum are similar in size. Up to eclosion, all glial processes shrink and increase in electron density. Most of the observations are discussed also in relation to findings in vertebrates.


Autoradiographic studies on the protein synthesis and the distribution of the newly synthesized proteins in oligodendroglial cells. The protein-synthesizing activity of oligodendroglial cells in the rat hippocampus as well as the migration of the newly synthesized proteins within these cells were examined by means of light and microscopic autoradiography when injecting 3H-leucine into the lateral ventricle. The autoradiographs of oligodendroglial cells were compared with the autoradiographs on hippocampal pyramidal cells of the same area. According to the quantitative evaluation of the autoradiographs the protein-synthesizing activity of the oligodendrocytes equals or may even exceed that of the pyramidal cells. In oligodendroglial cells most of the newly synthesized proteins migrate very rapidly from the rough-surfaced endoplasmic reticulum into the cisternae of the Golgi apparatus and disappear continuously. The proteins disappear from the Golgi apparatus simultaneously with the decrease in the radioactive concentration of the perikaryon.


Ultrastructural immunocytochemical localization of neurophysin and vasopressin in the median eminence and posterior pituitary of the guinea pig. With the use of tissue prepared by freeze-substitution and the unlabelled antibody enzyme technique, neurophysin and vasopressin were localized at the ultrastructural level in the pofterior pituitary and median eminence of the guinea pig. In the posterior pituitary neurophysin was found in the large neurosecretory granules (1300-1500 A) of axons, Herring bodies, and nerve terminals. In some of these axons immunoreactive neurophysin was found outside of granules in the axoplasm. By light microscopy neurophysin was found in both the zona interna and zona externa of the median eminence; this was confirmed by electron microscopy. In the zona interna as in the posterior pituitary, neurophysin was localized both inside and outside the large neurosecretory granules. In the zona externa, immunoreactive deposit was primarily located in granules with a diameter of 900-1100 A in nerve terminals abutting on the primary portal plexus. The distribution of vasopressin paralleled that of neurophysin except that the hormone was rarely extragranular. These results demonstrate for the first time that both neurophysin and vasopressin are present in granules of axons that are in contact with the hypophysial portal vasculature.


Ultrastructure of the thread cells in the slime gland of Japanese hagfishes, Paramyxine atami and Eptatretus burgeri. The thread cells in the slime gland of Japanese hagfishes, Paramyxine atami and Eptatretus burgeri were studied by light and electron microscopy. The mature thread cells are large elements (180 times 80 mu) filled with an intricately coiled thread, approximately 2 mu in diameter. The protein nature of the thread has been confirmed by histochemical examination. In the initial stage of growth, the thread consists of a bundle of distinctly parallel filaments approximately 90-120 A in diameter and a centrally located tubular component approximately 230-260 A in diameter which occurs singly or occasionally as a double and triple structure. The developing thread displays thin filaments, approximately 30-60 A in diameter. The thin filaments are composed of fine fibrous structures, subfilaments, approximately 10-30 A in diameter. On the outer surface of the thread a coating is apparent, giving it a fluffy appearance. Polysomal clusters consisting of five or six ribosomes are predominant. Fine fibrous structures are also found among the threads; they seem to have a spatial relationship with the polysomes and resemble the subfilament constituents of the thin filaments. From these results, it may be suggested that the fine fibrous structures synthesized by polysomes, twist together and coalesce into a thread. The problem of the polysome size and the molecular weight of the fibrous protein synthesized is discussed.


The membrane systems of the cardiac muscle cell of Munida tenuimana G. O. Sars (Crustacea, Decapoda). The membrane systems of the cardiac muscle cell of Munida tenuimana G. O. Sars are described. The sarcolemma invaginates at the Z level, forming tubules. Narrow tubules branch off in a longitudinal direction from these transverse and radially arranged tubules, forming a narrow transverse collar at the H level where dyadic and triadic junctions are formed with the sarcoplasmic reticulum.


The ultrastructure of normal and glycerol treated muscle in the ghost crab, Ocypode cursor. The ultrastructure of normal and glycerol treated fibers of the closer muscle of the ghost crab, Ocypode cursor, was studiedmthe muscle is composed of presumably phasic (short sarcomeres) and tonic (long sarcomeres) fibers, the latter greatly predominating. Horseradish peroxidase (HRP) was used as an extracellular tracer to delineate the tubular system (TS), and to determine to what extent this system becomes detached from the extracellular space as a result of glycerol treatment. Sarcolemmal clefts invade deeply into the muscle at Z-lines and I-bands; tubules invaginate into the muscle from the clefts and from the surface sarcolemma at the Z-lines, A-I overlaps and A-bands. A tubules are in frequent diadic or tetradic contact with the sarcoplasmic reticulum (SR), whereas Z tubules appear to be randomly associated with SR, terminal cisterns (TC) and Z-line fibrils. When HRP was administered to normal muscle, black reaction product was found adjacent to the outer surface of the sarcolemma, within the clefts and within profiles of the TS throughout the tissue. In glycerol treated muscle peripheral vacuolation frequently occurred; black reaction product penetrated only as far as the vacuoles and into dilated Z-line tubules, but was virtually absent from the rest of the TS. This lack of continuity between the extracellular space and the A tubules indicated disruption or constriction of the A tubules as a result of glycerol treatment, although Z tubule contact with the extracellular space appeared unimpaired. These findings provide ultrastructural correlates of the electrophysiological changes produced by glycerol treatment of the closer muscle of the ghost crab (Papir, 1973), namely, interference with excitation-contraction (e-c) coupling. The random association of the Z tubules with SR and TC, and their resistance to disruption by glycerol treatment, tend to endorse the claims that the Z tubules in crustacean muscle are not directly involved in e-c coupling (Brandt et al., 1965; Peachey, 1967; Selverston, 1967).


The distal ommatidium of the compound eye of the housefly (Musca domestica): a scanning electron microscope study. The distal aspect of the housefly ommatidium was surveyed by the scanning electron microscope. Attention was directed to the somal eminence of the superior central cell and the lens to large pigment cell junction. The underside of each lens facet exhibits six hexagonally arranged incisures. Into each of these indentations are fitted several large pigment cells. This hexagonal indentation appears to be a tenacious anchorage. Two corneal pigment cells laterally encircle the pseudocone and at their proximal extension they enclose the Semper cells and neck of the retinula. The somal eminence of the superior central cell is about 10 mum from the base of the corneal pigment cell enclosure. Micrographs were used to construct a diagram of the ommatidium above the basement membrane. Suggestions are made as to the functional correlates of the observed ommatidial structures.


The dormant buds of Rhabdopleura compacta (Hemichordata). Rhabdopleura has an overwintering stage that consists of two layers of cells surrounding a central yolk mass. This cellular part is surrounded by a thick electron dense capsule which is secreted by the bud itself. The capsule is probably impervious and protective to its contents. Blood vessels join the buds to the zooids of the colony. They form the probable route of transfer of yolk from the zooids to the dormant bud. The capsule of the dormant bud has some structural features in common with the black stolon of the adult zooids. The black stolon is probably formed in a manner similar to that which made the fusellar fabric of the periderm of fossil graptolities.


Studies on the fine structure of the cuticle of Porcellidium, crustacea copepoda. Two species of Porcellidium have been studied by scanning and transmission electron microscopy: P. viride from Banyuls-sur-mer, Mediterranian Sea and P. fimbriatum from Roscoff, English Channel. Both species live on green Algae of the genus Ulva. We confirmed previous descriptions of the cuticular ultrastructure in the main groups of Copepods. Four new characteristics however were shown to occur in the backcuticle of Porcellidium: 1. The presence of a system of highly differentiated external microvilli showing electron dense basal portions and less electron dense tips, from which thin filaments project towards a large population of Bacteria associated with the Copepod. 2. The surface of the cuticle resembles a lunar landscape with craters. The sheet of microvilli closely follows the contour of the cuticle. 3. The presence of branched cytoplasmic canals with swollen extremities (beneath the epicuticle) extending from the epidermal cells. 4. Systems of vesicles lying between the bases of the microvilli and the expansions (ampullae) at the tip of the cytoplasmic canals. The association of Bacteria with the cuticle is constant and many of these are apparently undergoing cytolysis; The system of microvilli and of cytoplasmic canals are apparently related to the presence of the bacterial microflora.


Occurrence of cell junctions and microfilaments in osteoblasts. Osteoblasts in the diaphysis of the tibia during endochondral ossification in young rats are attached to one another by nexus, by "adhaerens" junctions, and by simple appositions. "Adhaerens" junctions and nexus also occur between preosteoblasts and osteoblasts. Furthermore, to osteoblasts exhibit a network of microfilament bundles in the cell periphery overlying the osteoid. From this network bundles extend into the cell processes which protrude into the unmineralized matrix. The mean diameter of individual microfilaments is 5.9 +/- 0.06 nm. A possible role of nexus and microfilaments in controlled bone growth and differentiation is discussed.


Intracisternal polycylinders: a cytoplasmic structure in cells of the terrestrial slug Arion empiricorum Férussac (Pulmonata, Stylommatophora). Study of the digestive organs of the slug Arion empiricorum with the electron microscopy has revealed cytoplasmic structures that we call intracisternal polycylinders (ICPC). They consist of cylinders of cytoplasm (about 550 A in diameter) arranged in sheafs within cisterns of the endoplasmic reticulum. They appear in different cell types, being most common in the digestive epithelium of the midgut. Their morphology and apparent association with other cytoplasmic organelles such as mitochondria, peroxisomes, multivesicular and residual bodies suggests that the ICPC might be involved in exchange, transport and oxidation processes, contributing to the excretory function at a subcellular level.


Morphology of the "spindle-shaped body" in the developing tail of human spermatids. At the beginning of the late cap phase of the normal differentiation of human spermatids, a unique structure, the "spindle shaped body", occupies part of the future middle-piece. This spindle-shaped body was followed throughout its development, and its functional relationahip to the formation of the fibrous sheath is discussed. The spindle-shaped body disappears when the fibrous sheath is completed and the annulus moves down, giving rise to the middle-piece.


Morphology of the perivascular regions of the rat neural lobe in relation to hormone release. Neural lobes of rats subjected to dehydration by drinking 2% saline for four days were examined electron microscopically and compared to untreated controls. The ultrastructure of the blood vessels and the tissues surrounding them were examined and it was found that, although few exocytotic figures could be seen in either group of animals, a significantly larger (P smaller than 0.01) number os small vesicles were found in nerve endings adjacent to the perivascular space in the saline treated group when compared to nerve endings not closely associated with blood vessels. No differences were found in the control group of animals, which supports the suggestion that the vesicles could arise from a membrane recapture process.


Structure and histochemistry of the normal intestine of the fowl. III. The fine structure of the duodenal crypt. The fine structures of the development and maturation of intestinal chief cells from the duodenal crypts of the fowl has been described in detail. Three areas within the crypt can be recognised: 1) the crypt base where cell division is frequent but cell development is minimal; (2) the mid-crypt region where rapid growth and development of the cells takes place; and (3) the zone of differentiation where final developments and functional maturation occurs. The structure of the fowl's intestinal crypt is very similar to that described for the mammals. The results are discussed in relation to previous histochemical studies.


The labrum of Schedorhinotermes minor soldier (Isoptera, Rhinotermitidae): morphology, innervation and fine-structure. The labrum of Schedorhiontermes minor soldier was examined to determine the distribution, types and structures of sense organs present with both light microscopy and scanning and transmission electron microscopy. Three types of sensilla were recognized: companiform sensillae and two types of sensillae trichodea, the short bristles and the long bristles. The companiform sensillae are singly-innervated receptors distributed in large numbers on the anterolateral margins of the labrum. The short and long bristles are multi-innervated; the former are found all over the surface, the latter are much more scarce and are found only at the front of the labrum. Both are at the same time chemo- and mechanoreceptors. The labrum is strewn with many glandular pits and exhibits at its apex a brush of cuticular not innervated spines. On the basis of ultrastructural evidence and of what we know of the defense mechanisms of the soldier, a functional interpretation is attempted.


Electron microscopy of the arcuate nucleus of normal and 5-hydroxydopamine treated cats. The arcuate nucleus of normal cats and of cats treated with 5-hydroxydopamine (5-OHDA) was investigated by electron microscopy. The neurons of the arcuate nucleus were classified into three types, clear, intermediate and dark, according to their fine structure. The clear type contained numerous dense-cored vesicles and well developed cell organelles. All three types were frequently seen to be partially surrounded by glial processes. Many axo-somatic and axo-dendritic synapses mostly small in diameter were also observed around the neurons. Synaptic contacts were demonstrated between axon endings and axonal processes which contained elementary granules. After administration of 5-OHDA small and large dense-cored vesicles appeared in the nerve endings surrounding the neurons. The relationship between the dense-cored vesicles in the perikarya and dopamine was briefly discussed.


Ultrastructural analysis of the granulosa--luteal cell transition in the ovary of the dog. The transition from ovarian granulosa to lutein cell during the estrus cycle of 60 pregnant and non-pregnant beagle bitches was analyzed by light and electron microscopy (both 100 and 1000 KV). Early proestrus was characterized by a gradual rise in serum estrogen levels, hyperplasia of the granulosa cells, the accumulation of follicular fluid, and the development of tortuous intercellular channels. During the second half of proestrus, serum estrogen levels continued to rise, but growth, division, and differentiation of the granulosa cells was minimal. Estrus was marked by the first acceptance of the male and a well-defined LH peak In the subsequent 24 hour period, the granulosa-lutein cells hypertrophy rapidly and develop a large Golgi apparatus, small profiles of granular endoplasmic reticulum, numerous microfilaments, and large gap junctions between the cells. Mitochondria also proliferate, enlarge, and elongate, but retain lamelliform cristae. Luteinization of the cells and progesterone secretion begin just after ovulation which in turn occurs about 24 hours after the LH peak. On the third and fourth day of estrus, numerous small vesicles of agranular endoplasmic reticulum fill the extoplasm and the mitochondria swell up and round off. The vesicles rapidly fuse into whorled and flattened cisternae or anastomosing tubules of agranular endoplasmic reticulum, while the mitochondria develop tubulovesicular cristae. These structures gradually become organized with respect to the basal lamina. The Golgi apparatus is centered over the pole of the nucleus that faces the pericapillary space. Stacked and whorled cisternae of agranular ER develop in the lateral margins and avascular end of the cell while mitochondria and tubular elements of agranular ER predominate in the central medial and most basal portions of the cytoplasm. Microfilaments are ubiquitous and appear to be instrumental in this orientation process. The cell surface develops three distinct regional specializations that coincide with the underlying cellular compartments: interconnecting pleomorphic folds fill the pericapillary space; long tenous microvilli project from the lateral cell surface and form tortuous intercellular channels and canaliculi; and large gap junctions form along the margins of the cell furthest removed from the basal lamina. By the sixth day of estrus, the granulosa-luteal cell transition is nearly complete and serum progesterone levels are on the rise.


The glomeruli of the human and the rat kidney studied by freeze-fracturing. Glomeruli isolated from rat and human kidneys were studied using the freeze-fracture technique. Discontinuous zonulae occludentes and gap junctions were found in the replicas of the split plasma membrane of the endothelial cells. A diaphragm across the endothelial pores was not demonstrated. The central layer of the basement membrane, corresponding to the lamina densa described in thin sections, revealed a coarse substructure. A slit membrane between the pedicles of the podocytes was not detectable; however, its position was indicated by the different texture of the replica, which abruptly changed at the transition of the basement membrane to the primary urinary space. Furthermore, at the level of the slit membrane arrays of particles were present within the cleaved membrane of the pedicles, probably representing the attachment points of the slit membrane. Isolated strands of a zonula occludens as well as gap junctions were seen on the split plasma membrane of the podocytes. The mesangial cells could be identified by their contiguity to the endothelial cells and by their numerous gap junctions.


Junctional complexes of the tubular cells in the human kidney as revealed with freeze-fracture. Intercellular junctions between human kidney tubular cells were studied by the freeze-fracture technique. The number of strands of the zonulae occludentes increased gradually from the proximal segment to the collecting tubule. Only one strand was visible in the proximal segment (in contrast to 2-4 strands of the neighbouring Bowman's capsule). In the thin segment 2-4 strands were revealed. In the distal segment 1-5 strands were present in the pars recta, 4-6 in the pars convoluta. The most extensive and complex zonulae occludentes were found in the collecting tubule. Gap junctions were seen only between proximal tubular cells. The extent of the zonulae occludentes along the tubules in human kidneys is very similar to that observed in the kidney tubules of other mammals. The findings accord well with electrophysiological measurements and with the results of tracer studies on experimental animals.


Different populations of granules and their distribution in the hypothalamo-neurohypophysial tract of the rat under various experimental conditions. II. The median eminence. In connection with previous studies (Krisch, 1974), a morphologic analysis of the median eminence of male, female, pregnant, and thirsting rats has been made, in order to evaluate: 1. whether the median eminence is an additional area where oxytocin and vasopressin may be released from neurosecretory axons in the zona interna; 2. whether it is possible to distinguish different populations of axons according to the mean diameters of their granules in the external zone of the median eminence. In the zona interna of the male and the female control animals, the oxytocin- and vasopressin-containing granules have already reached their final diameters, i.e. their size remains constant until they reach and are stored in the neurohypophysis. However, the relative proportions of these populations in the fibre layer of the median eminence indicate certain differences between male and female animals, concerning the turnover of oxytocin vasopressin. In pregnant, as well as in thirsting animals, there is an apparent decrease of the mean granule diameters in oxytocin- and vasopressin-containing axons. In particular in the latter group, ballooned axons in the fibre layer of the median eminence, containing disintegrating granules, tubular structures filled with electron dense material, and fine-flocculent material in the axoplasm, together with the morphometric results, support our concept that in case of highly increased peripheral demand the contents of the mature, large granules are released into the axoplasm of the fibre layer in the median eminence. In addition, axons containing granules smaller than 115 nm may be classified into four populations with mean diameters of 84 nm, 96 nm, 103 nm, and 100n. The same populations are found in the palisade zone of the median eminence as well as in the pericapillary zone, but in contrast to the zona interna there is a fifth population of axons containing very small granules with a mean diameter of about 70-75 nm. The relative proportions of these five populations differ between the zona palisadica and the pericapillary zone on the one hand and between the experimental groups on the other hand. Some morphological findings concerning the tanycytes are discussed with respect to previously published data.


The renal chloride cell of the fresh-water catfish, Parasilurus asotus, with special reference to the tubular membrane system. The kidney of the fresh-water catfish, Parasilurus asotus, was examined by electron microscopy. A special type of cell, very similar in appearance to the chloride cell of the teleostean gill filaments, is found in the kidney and is referred to as a renal chloride cell. This cell is characterized by an extensive tubular membrane system with a rather constant diameter of approximately 600 A. A number of mitochondria are closely associated with this system. Application of ruthenium red as an extra-cellular space marker revealed that the tubular system is a highly organized derivative of the cell membrane, infolded from the basal and lateral surfaces of the cell. The fine structural resemblance to other types of cells known to possess active transport of electrolytes suggests that these cells are involved in intrarenal osmoregulation.


On the pars cerebellaris loci coerulei within the cerebellum of man. A flat cerebellar nucleus of melanin containing cells in the vicinity of the nucleus fastigii of man is described as part of the nucleus coeruleus.


The structure of symplasmic early oocytes and their enveloping sheath cells in the polychaete, Platynereis dumerilii. 1. Early oocytes of Platynereis dumerilii are found in clusters floating in the coelom. The oocytes of a cluster form a syncytium which is enveloped by several sheath cells. 2. At stage 2, only a single sheath cell per cluster remains, and it penetrates the group of rounded oocytes, enveloping each one of them. At stage 4, this cell contains a reticular basket made up of bundles of filaments and is inferred to be degenerating, from the presence of vacuoles, clumps of pigment-like material, and atypical mitochondria. 3. Synaptonemal complexes are typical of the nuclei of stage 2 oocytes. Oocytes of stage 4 (early vitellogenesis) contain stacks of endoplasmic reticulum in a distinctive arrangement, with interspersed electron-dense masses. Similar masses accumulate in the cytoplasm close to the nucleus and adjacent to the nuclear pores. 4. From the present observations, a physical supporting rather than a nutritive function is attributed to the sheath cell, which ensures cohesion among the oocytes connected with each other throughout the cluster phase by cytoplasmic bridges. This finding is discussed with respect to conclusions drawn from oocyte transplantation experiments.


Evidence for myoblastic potential of satellite cells in denervated muscle. The failure of denervated muscle to undergo effective regeneration, despite reported increases in the number of muscle satellite cells, warranted an investigation of the viability and myoblastic capacity of these cells present in denervated muscle. Four types of satellite cells present in muscle denervated for three weeks are described, based on their ultrastructure and relationship to their principal fiber. The increased number of ribosomes, including helically arranged polysomes; the number of Golgi complexes; the presence of microtubules; the branching subsarcolemmal tubular system; and the appearance of regularly arranged 96 A microfilaments with diffuse electron dense areas are structural features of satellite cells that are similar to those of developing myoblasts in growing and regenerating muscle. The electron microscopic observations suggest that "activated" satellite cells do have myoblastic potential. Possible explanations for the ultimate failure of denervated muscle to regenerate include: 1) the inability of the muscle to produce satellite cells rapidly enough to keep pace with muscle degeneration; 2) a cytotoxic effect produced by the degenerating muscle fiber on the satellite cell; and 3) the inability of satellite cells to form stable, mature multinucleated fibers in the absence of the trophic effect of the nerve.


Ultrastructure of the dorsal hemal vessel in the sea-cucumber Parastichopus tremulus (Echinodermata: Holothuroidea). The dorsal hemal vessel in Parastichopus consists of three distinct layers: An outer flagellated epithelium, an intermediate circular muscle layer and an inner connective tissue layer which nearly fills the lumen. Between the outer and intermediate layer runs strands of nerve fibers. Each coelomic epithelial cell has one flagellum and some microvilli. It contains a number of different vacuoles and a few bundles of tonofilaments. One special type of vacuole which contains well organized myofilaments is described. Each muscle cell contains one myofibril of a non-striated type consisting of thick and thin filaments and no dense bodies. The sarcoplasmic reticulum is poorly developed, but peripheral coupling are frequently found. The muscle cells in the dorsal hemal vessel of Parastichopus are compared with other muscles in echinoderms and muscle types described in other phyla.


Distribution and morphology of amphibian extra-adrenal chromaffin tissue. 1. The distribution and morphology of chromaffin cells in the para-aortic region and in the ganglia of the paravertebral sympathetic chain was studied with fluorescence histochemistry and electron microscopy. 2. Four types of chromaffin cell were distinguished largely on the basis of their vesicular content: Type I cells contain large, electron-dense vesicles (600-7000 A) and are comparable to noradrenaline-containing cells in the adrenal gland, Type II cells contain large, vesicles (600-7000 A) that are filled with a less electron-dense material than that in Type I cells and are comparable to adrenaline-containing cells in the adrenal gland, Type III cells contain smaller vesicles (1000-3000 A) that are incompletely filled with an electron-dense material and may represent cells that have been depleted of their catecholamines by stimulation, Type IV cells are clearly different from the other three cell types with respect to the size and appearance of the vesicles (1000-1500 A), nuclei and rough endoplasmic reticulum and may represent immature sympathetic neurons. 3. Nerve profiles, identified as cholinergic, were found in close apposition with all four cell types. No examples of a close association between processes of chromaffin cells and sympathetic neurons were found.


Ultrastructure of the prothoracic gland cells of the last instar of Galleria mellonella in relation to the state of development. The prothoracic glands of the last instar of Galleria mellonella undergo characteristic alterations of their cellular fine structure closely related to cellular activity. During progressive secretory activity of the gland cells there are extensive plasmalemmal infoldings and formation of a pronounced lacunar system. Mitochondria of the active cell phase are characterized by a specific increase in size and paler colour of the matrix. In contrast to the alterations, nuclei, ER and Golgi cisterns do not undergo any submicroscopic changes during the different phases of cellular activity. The relationship between the substructural phenomena and the specific phases of cellular activity are discussed.


Satellite cells of the rat soleus muscle in the process of compensatory hypertrophy combined with denervation. Compensatory hypertrophy was induced in the rat soleus muscle by sectioning the tendon of the ipsilateral gastrocnemius and plantaris muscle. Seven days after tenotomy of synergistic muscles, when soleus hypertrophy attains about 40%, the number of satellite cells (expressed as percentage of all muscle nuclei found in the same cross-sections) as revealed by electron microscopy, was increased from 5.8+/-0.06% in the normal soleus muscle to 16.6+/-1.26%. After four days' denervation of the soleus muscle the percentage of satellite cells was increased to 7.2+/-0.62%. In experiments where hypertrophy of the soleus muscle was combined with denervation three days after tenotomy of synergists, and examined after another four days (during which time it loses, as has previously been shown, over 40% of its predenervation weight), the number of satellite cells was greatly increased to 29.9+/-3.42%. This increase is apparently due to two independent processes which take place during the first postoperative period: a) mitotic division of satellite cells during the early stages of compensatory hypertrophy and b) pinching off of muscle nuclei from rapidly atrophying muscle fibres due to subsequent denervation. Activation of satellite cells was mainly manifested by expansion of smooth and especially of rough endoplasmic reticulum, a rich Golgi complex, high pinocytotic activity, increased number of ribosomes and by nuclear changes. Concomitantly with the increased number of satellite cells, proliferation of fibroblasts, macrophages and mast cells could be observed.


Growth hormone-release inhibiting hormone (GH-RIH) pathway of the rat hypothalamus revealed by the unlabeled antibody peroxidase-antiperoxidase method. Utilizing the unlabeled antibody enzyme method, we investigated the distribution of hypothalamic elements immunoreactive with antibodies to growth hormone-release inhibiting hormone (GH-RIH). Immunostained elements, resembling neural processes, are distributed along a pathway corresponding to a portion of the tuberoinfundibular tract. However, GH-RIH fibers are caudal, dorsal and medial to LH-RH fibers detected by the same technique. Similar topographic arrangements are noted in coronal and sagittal sections. Comparable results were obtained with two different preparations of antisera to GH-RIH. No cell bodies specifically stained by anti-GH-RIH were detected. Our data agree with those of other investigators using immunohistochemical techniques.


Myelinated nerve fibers in the rat kidney. Light- and electron microscopic studies. Thinly and richly myelinated nerve fibers in the rat kidney are demonstrated by light and electron microscopy. They run within the peripheral nerves in the periadventitia of the arteria rencularis and arteria arcuata and seem to end in the innermost renal cortex at the boundary to the renal medulla. Sporadically, a single myelinated fiber is found in this region, running near tubuli or in the neighbourhood of a glomerulus. No ganglion cells were seen within the renal parenchyma. The intrarenal medullated nerve fibers are assumed to be afferent. They sometimes showed reactive and degenerative changes in pathologically altered kidneys.


The effect of tetrabenazine on the accumulation of noradrenaline in constricted postganglionic sympathetic nerves in vitro. The accumulation of noradrenaline proximal to a constriction applied to cat hypogastric nerves in vitro has been studied in preparations treated with tetrabenazine. The accumulation of amine was almost completely abolished by the drug. Evidence is presented which suggests that tetrabenazine exerts a direct noradrenaline-depleting effect on the intraneuronal storage vesicles. Recovery of noradrenaline levels after the removal of the drug was rapid and was effected by the biosynthesis of new noradrenaline within the axon.


The microanatomy of the compound eye of Munida irrasa (Decapoda: Galatheidae). The compound eye of Munida irrasa differs in several respects from the typical decapod eye. The proximal pigment is found only in retinula cells. The eccentric cell is extremely large and expanded to fill the interstices of the crystalline tract area; thus, a typical "clear-zone" is absent. Six retinula cells course distally to screen two sides of the crystalline cone. There are approximately 12,500 ommatidia in each compound eye. There are several similarities to the typical decapod eye. Each ommatidium is composed of a typical cornea, corneagenous cells, crystalline cone cells, crystalline cone, crystalline cone tract and eight retinula cells. Distal pigment cells are present and surround the crystalline cone. The distal processes of the retinula cells also contain pigment. The retinula cell processes penetrate the basement membrane as fascicles composed of processes from adjacent retinulae.


Comparative ultrastructure of ureteric innervation. The distribution and structure of the ureteric nerves in a small series of mammals was compared with that previously demonstrated in the rat. There was marked interspecies variation in the extent to which the nerves penetrated the wall of the ureter and in the degree of development of the deep submucous plexus. In animals with a highly developed deep submucous plexus, terminal arterioles frequently passed through the muscle coat before breaking up into capillaries. These vessels were surrounded by a fine periarteriolar plexus and were accompanied in their course through the muscle coat by one or more branches of the adventitial nerves. Intramuscular nerves not related to arterioles contained few axons with terminals classifiable as either adrenergic or cholinergic, and in animals in which the muscle cells were arranged in fascicles rather than in sheets, the nerves were typically interfascicular in position. As in the rat, only the periarteriolar plexuses contained large numbers of adrenergic axons. Cholinergic axons were generally few, but were not uncommon in the deep submucous plexus when this was well-developed. The majority of the terminals encountered in the intramural nerves contained variable and usually small numbers of both clear and large dense-cored vesicles. The relationship between these terminals and those defined in the submucous nerves of the rat ureter was discussed and it was suggested that the marked variations in the diameter of the axons in the terminal areas and in the number of vesicles in the terminals were related to the effects of the mechanical and other derangements which occur during processing.


Multiple rough endoplasmic cisternae in the endocrine pancreas of the adult rat. Multiple rough endoplasmic cisternae were found in the parenchymatous cells of the endocrine pancreas of the adult rat (alpha, beta, D and intermediary cells) and were especially developed in beta cells. They are considered to be normal constituents of the parenchymatous cells of the endocrine pancreas. Their close proximity to Golgi dictyosomes and the accumulation of secretory material sometimes seen at the extremities of such cisternae, suggest that they may have a role in the secretory activity of these endocrine cells.


Nonrandom distribution of goblet cells around the circumference of colonic crypt. The ascending colon of the guinea pig was cut serially and stained with the periodic-acid-Schiff-hematoxylin method. Maps of transversely sectioned crypts were prepared using a microscopic eye-piece projector. The number and angular positions of goblet cells were mapped around the circumference of transverse sections of the crypt. A method of the "statistics of the circumference" was introduced in order to assess the pattern of distribution of goblet cells. This distribution was found to be significantly nonrandom. The nonrandomness is such that the goblet cells tend to occupy positions of the crypt circumference in maximal distances from each other.


Ultrastructure of the taste bud of the human fungiform papilla. The taste bud of the human fungiform papilla was examined by electron microscopy. Typical type I, type II, and type III cells were found along with contact sites with nerve endings. Vesicles in nerve fibers contacting type I and type II cells suggest that these cells may receive efferent impulses, whereas vesicles and granules in type III cells adjacent to (afferent) nerve fibers support the view that type III cells are sensory receptors. All of these features are virtually indistinguishable from those previously reported in fungiform taste buds of other mammals.


An association between mitochondria and vesicles in smooth muscle. Two methods are described for measuring the mitochondrion-vesicle association seen by electron-microscopy in thin sections of the guinea-pig taenia coli. Both methods are based on comparisons of the observed distributions with predicted random distributions. It was found in control muscles that mitochondria were consistently nearer to vesicles than corresponding random points. 1 mM ouabain treatment reduced the mitochondrion-vesicle association for mitochondria which were closer to the membrane surface than 130 nm. Quantitative investigation of the freeze-etch structure of the membrane fracture faces is also reported, confirming the observation that membrane particles are more numerous in vesiculated membrane regions of smooth muscle.


Histochemical distribution of monoamines in the hypothalamo-hypophysial region of the lamprey, Lampetra japonica. The distribution of monoamine fluorescence was studied in the hypothalamohypophysial region of the lamprey. Groups of intensely fluorescent cells were observed in the lateral walls of the caudal part of the third ventricle. The anterior part of the neurohypophysis which is situated over the pars distalis showed weak fluorescence. The posterior part of the neurohypophysis which is contiguous to the pars intermedia contained highly fluorescent material in its rostral part. The distribution of monoamines in the lamprey neurohypophysis is compared with that in the higher vertebrates and their functional significance is discussed.


Ultrastructural evidence for sinusoid spaces and coupling between pituicytes in the rat. The pericapillary palisade of the rat neurohypophysis was examined by means of thin-section and freeze-etch electron-microscopy. Special attention was given to pituicyte processes intermingled with neurosecretory terminals. These processes are identified by the presence of lipid droplets and ribosomes. Extracellular spaces are conspicuously enlarged in circumscribed regions between fingerlike protrusions of pituicyte processes. Neurosecretory axons seem to have free access to these enlarged spaces. Zonulae occludentes often combined with small gap junctions are found at the border of these sinusoid spaces. Gap junctions and occasionally intermediate junctions are seen between pituicyte processes. The topographic relationship and the functional significance of these structural features remain to be further elucidated.


Acrosome formation and the centriolar complex in the spermatozoa of Sabella penicillum (Polychaeta): an electron microscopical study. The acrosomal vesicle of Sabella penicillum spermatids consists of an electrondense core and a more transparent surrounding zone. During subsequent differentiation the vesicle membrane forms several invaginations in the juxtanuclear area. These invaginations later establish contact with the core. In the mature spermatozoon the spaces between the invaginations appear as electron-dense "tubules"; this is probably due to a shift of material from core to periphery. The ultrastructure of the centriolar complex is described in detail.


Ultrastructure of developing germ cells in the fetal human testis. Electron microscopic studies of the testis were performed on 12 human embryos and fetuses between 9 and 30 weeks post conceptionem. According to their ultrastructural features, the fetal germ cells could be divided into the following three stages of differentiation: 1) gonocytes, 2) intermediate cells, and 3) fetal spermatogonia. Sertoli cells were present among the germ cells in all the testes studied. The gonocytes showed the highest nucleo-cytoplasmic ratio. Their round nucleus contained a centrally located, prominent nucleolus. The cytoplasm displayed a well developed Golgi apparatus, lipid droplets and parallel arrays of short cisternae of the rough surfaced endoplasmic reticulum (rER). Microfilaments were numerous, particularly just beneath the cell membrane. The intermediate cells were found to extend several cytoplasmic processes and to contain a moderate number of long, branched and/or widened rER cisterna which were frequently connected to the perinuclear cisterna. Intermediate cells were often connected to one another by intercellular cytoplasmic bridges. The fetal spermatogonia also displayed cytoplasmic bridges. These cells showed the lowest nucleo-cytoplasmic ratio and more condensed nuclear chromatin. The mitochondria were situated close to the nucleus. Many of them were connected by a cementing substance. Lipid droplets and rER cisternae were rare in these cells. Infoldings of the inner nuclear membrane were often present in the gonocytes and in the intermediate cells, but were rarely observed in the fetal spermatogonia. Glycogen particles, polyribosomes, and chromatoid bodies ("nuage") were present in all the three germ cell types. With the maturation of the fetus, the number of gonocytes was found to decrease, whereas the number of fetal spermatogonia increased. The Sertoli cells also changed their ultrastructure, showing an increase in the number of rER cisternae, as well as of microfilaments, lipid droplets, and secondary lysosomes.


Effects of nerve stimulation and denervation on secretory material in submandibular striated duct cells of cats, and the possible role of these cells in the secretion of salivary kallikrein. Striated ducts in cats after 24 hours starvation normally contained glycogen, especially in the basal regions. They also contained neutral mucin and tryptophan in apical parts of "light" cells and small irregular "secretory" granules were found in a similar distribution by electron microscopy.--Parasympathetic nerve stimulation caused a loss of glycogen but no apparent change in the apical secretory material, despite a copious secretion.--Sympathetic stimulation caused a loss of glycogen and an extensive depletion of apical secretory material, although the salivary flow was small.--Parasympathetic denervation caused progressive atrophy of striated ducts and oedematous degeneration of some cells occurred. Persisting "light" cells tended to contain few basal infoldings, few mitochondria and little apical secretory material.--Sympathetic denervation caused a loss of apical secretory material between 2-4 days, which may have been due to "degeneration activation". Thereafter little change was evident but some ductal atrophy had occurred by 32 days.--These changes in ductal secretory material correspond more closely than acinar changes to the alterations in glandular and salivary kallikrein resulting from similar experiments by other workers. It therefore seems likely that submandibular salivary kallikrein in the cat is present in the secretory material of striated ducts.


The fine structure of the centrohelidian heliozoan Heterophrys marina. The fine structure of Heterophrys marina (Centrohelidia, Heliozoa) is described with special reference to centroplast structure, morphogenesis and "behavior" of kinetocysts (= axopodial granules which perform saltatory movement), and formation of organic spicules in a new type of organelle located in the plasma membrane. A low calcium pretreatment and fixation was used to improve preservation of highly labile axopodia which near their distal end contain a single microtubule (MT) only. Two varieties of H. marina with a respective maximum of 6 and 12 MTs per axopodium, and 2 hitherto undescribed species, H. elati and H. multipoda, were found among 9 stocks collected in Europe and North America. In all species only the central 6 MTs of each axoneme originate from a scaffolding layer of electron dense material which surrounds the central granule. Evidence is presented which indicates that in Heterophrys self-linkage is not the only principle of MT pattern generation but that instead precisely localized MT nucleation and specific linkage of MTs within the cortex of the centroplast lead to the MT patterns observed. Prekinetocysts originate from vesicles found in the neighborhood of the dictyosomes. After maturation the kinetocysts become attached to the plasma membrane which seems to play an important role both in selection of particles transported in the axopodia and particle movement as well.


[Pathology in the current scientific and technological revolution]. Scientific and technological development in morphological disciplines has created an creates  unheard of possibilities for scientific research and practical examination of morphological changes and in its consequences has contributed also in a substantial way to a change in fundamental views on the subcellular and supramolecular structural level of the organization of living matter. Despite this pathology is faced with difficulties and has at present many unresolved theoretical and practical problems. Pathology has expanded so much that is differentiation as regard contents and methods is inevitable to preserve its integrity and to promote its integrity with other disciplines in particular biochemistry of tissue changes. The basic types of activity of pathology will remain also in future (histological) biopsy, cytodiagnostics and necropsy whereby it is necessary to use to an increasing extent new methods contributed by the scientific and technological revolution. It must not be forgotten that pathology is not only a specialized but also scientific discipline and important source for all doctors in their therapeutic and preventive and scientific activities.


[Chronic thrombosis of the truncus of the pulmonary artery at the foramen ovale late patens]. In a 54-year-old man who suffered from chronic cardiac insufficiency with terminal graded cyanosis on necropsy a foramen ovale late patens was found with massive chronic thrombosis of the trunk and main branches of the pulmonary artery above extensive partly ulcerous atheromatous plaques. The thrombosis is considered autochthonous by the authors.


[Fatal traffic accidents in pedestrians]. The author analyzed a group of 156 pedestrians (70 men and 86 women) above 50 years (Me = 72 years in men and 72.5 years in women) who died in 1967-1972 as a result of traffic accidents in the catchment area of the University Hospital in Prague 10. Head injuries were recorded in 73%, injuries of the chest in 62%, of the abdomen in 30%, of the spine in 26%, of the pelvis in 52%, of the upper extremities in 26% and of the lower extremities in 51% of the injured. In 20 (12.8%) a single injury was involved, in 136 (97.2%) multiple injuries, most frequently injuries of three parts of the body were observed - in 43 (27.5%) of the injured. The curve illustrating the number of surviving subjects in relation to the time which had elapsed since the injury displayed two definite and two indicated inflexions suggesting increased lethality. The first definite inflexion was between the second and third hour after injury and in those who died during this period fractures of the spine, bones of the lower extremities and pelvic bones with retroperitoneal bleeding were more frequent. The second definite inflexion was 36-48 hours after injury and in the patients pulmonary complications (atelectases, incipient inflammations) were more frequent. The indicated inflexion which was on the 9th day after injury was due to bronchopneumonias which were often observed at that time. Due to the small number of observations the authors were unable to interpret the infexions found on the 7th and 11th day after injury.


[Automation elements in the processing of serial analyses of blood alcohol]. Equipment and method are described for processing results of serial analyses of alcohol in blood. By using these simple automation elements the productivity of work can be increased.


Mechanism of action and fate of the fungicide chlorothalonil (2,4,5,6-tetrachloroisophthalonitrile) in biological systems. 2. In vitro reactions. The reaction characteristics of chlorothalonil with glyceraldehyde-3-phosphate dehydrogenase (GPDH), from yeast, (EC 1.2.1.12) were studied in vitro. Enzyme inhibition was related to the amount of [14C]chlorothalonil bound to the protein. Kinetics of enzyme inhibition was non-competitive for the substrate glyceraldehyde-3-phosphate (GAP) (Ki = 0.42 muM). Reversal of enzyme inhibition could not be demonstrated with the low molecular thiol dithiothreitol (DDT), although the thiol did protect the protein against the toxic action of the fungicide. Because 5,5' dithiobis-(2-nitrobenzoic) acid (DTNB) reduced the binding of 14C-labeled fungicide by approximately 90% it is postulated that chlorothalonil affects catalytic activity by reacting with the 4 sulfhydryl sites (cysteine-149) responsible for the binding of GAP. Certain reaction characteristics of the trichloromethyl fulfenyl fungicides with GPDH were found to be similar to those of chlorothalonil. However, chlorothalonil differed from those fungicides in that it did not react with non-thiol groups of either GPDH or alpha-chymotrypsin (alphaCT) and had a slower reaction rate with the GPDH. It is suggested that the differences in reaction rates of the fungicides are due to the molecular size and the chemical nature of the reactive toxiphores.


Increased urinary excretion of labelled deoxyribonucleosides in rats with stable pre-labelled DNA treated with methyl methanesulphonate or nitrogen mustard. After the DNA of newborn female rats had been labelled by repeated injections of [14C]orotate (totalling 36 mu Ci) during the first 3 weeks of life, approximately 1,000,000 dpm were found in the DNA of the liver, lungs, kidneys, gut, brain, heart and spleen of 8-week-old rats. Methyl methanesulphonate (MMS) (80 mg/kg) and di-(2-chloroethyl)methylamine (HN2) (5 mg/kg) injection increased the amount of 14C-labelled DNA pyrimidine nucleosides excreted in the urine to 5000 dpm from 350 dpm before injection. The effect on RNA products was much less marked.


Methylation of DNA in various organs of C57B1 mice by a carcinogenic dose of N-methyl-N-nitrosourea and stabiltty of some methylation products up to 18 hours. Female 6-8-week-old (57B1 mice were injected i.p. with N-methyl-N-nitrosourea (MNUS) (14C or 3H-methyl-labelled) in saline (80 mg/kg) and DNA was isolated from bone marrow, small bowel, kidneys, liver, lungs, spleen and thymus at various times thereafter up to 18 h. Methylation of DNA was found in all organs examined, and by analyses using column or paper chromatography of DNA hydrolysates, the extent of methylation of DNA purines was determined. Methylated guanine residues (at N-3, N-7 and 0-6 positions) were stable in DNA up to 18 h, but methylated adenines (at N-3 or N-7) were removed from DNA of all organs examined; the overall half-life of methyladenines was about 3 h, but removal appeared to occur in a biphasic manner, with a proportion of methyladenine remaining relatively stable. This relative stability was somewhat more marked in bone marrow than in other organs.


Changes in the reactivity of proteins of rat liver ribosomes against [14Ciodoacetamide depending on their organization in ribosomal subparticles, 80S ribosomes and on the attachment of poly-(U). (1) The isolated mixtures of ribosomal proteins can be substituted by [14C]-iodoacetamide up to an average of about 2 equivalents per 20,000 dalton. The extent of substitution of single proteins measured after two-dimensional polyacrylamide gel electrophoresis shows that all proteins are reactive. (2) Also in the subunits, all proteins are accessible to substitution. Compared with isolated proteins, however, the reactivity is decreased and the amount of labelling for most proteins ranges as low as 5 to 20%. (3) Reassociation of ribosomal subunits decreases the reactivity of 12 proteins of the small subunit and that of 20 proteins of the large subunit. (4) The presence of messenger inhibits the substitution of 10 proteins of the small subunit and of 6 proteins of the large one. (5) Seven proteins of the small subunit and 3 proteins of the large one are influenced both by the other subunit and by messenger-RNA.


Effects of norepinephrine and angiotensin II on the determinants of glomerular ultrafiltration and proximal tubule fluid reabsorption in the rat. In 26 Wistar rats with surface glomeruli, the determinants of glomerular ultrafiltration and peritubular capillary uptake of proximal reabsorbate were studied before and during intravenous infusions of norepinephrine or angiotensin II. Regardless of whether renal perfusion pressure (AP) was permitted to increase, both hormones produced elevations in single nephron filtration fraction due to declines in glomerular plasma flow with little change in nephron glomerular filtration rate. The resulting large increases in the efferent arteriolar oncotic pressure, piE, were accompanied by equivalent increases in the mean glomerular transcapillary hydraulic pressure difference, deltaP. Equality of piE and deltaP, denoting filtration pressure equilibrium, obtained before and during infusion of either hormone. Por both hormones, when elevations in AP were allowed, marked and roughly proportional increases in the resistance to blood flow through single afferent and efferent arterioles occurred, whereas when increases in AP were prevented by partial aortic constriction increases in resistance were confined primarily to the efferent arteriole. Tespite the marked increases in piE, absolute rates of proximal tubule fluid reabsorption, on the average, were unchanged by these hormones due to the opposing effects of marked decreases in efferent arteriolar plasma flow rate and, to a lesser extent, increases in peritubular capillary hydraulic pressure.


Effects of extracellular calcium and sodium on depolarization-induced automaticity in guinea pig papillary muscle. Regenerative discharge of action potentials is induced in mammalian papillary muscles by passage of small depolarizing currents. In this paper, the effects of various extracellular calcium and sodium concentrations and of tetrodotoxin on this phenomenon were studied in guinea pig papillary muscles in a sucrose gap chamber. Phase 4 diastolic depolarization was found to be associated with an increase in membrane resistance. The slope of phase 4 depolarization was decreased by reductions in extracellular calcium or sodium concentration. The range of maximum diastolic potentials and the thresholds from which regenerative potentials arose were reduced, especially at the positive limit of potentials, by a reduction in either ion. It was concluded that both calcium and sodium influence diastolic depolarization and participate in the regenerative action potentials of depolarization-induced ventricular automaticity.


Effect of sympathetic denervation on smooth muscle cell proliferation in the growing rabbit ear artery. The effect of sympathetic denervation on the uptake of 3H-thymidine (3H-Tdr) into the ear artery of a growing rabbit was studied in vitro and in vivo. Uptake into the right artery was compared with that into the left 2 and 3 weeks after left superior cervical ganglionectomy in 4-week-old rabbits. Denervation was confirmed by the absence of catecholamine fluorescence. The total uptake of 3H--Tdr was determined by scintillation spectrometry, and its distribution in the artery wall was studied by light microscope autoradiography. The denervated ear artery took up significantly less DNA precursor and exhibited fewer labeled vascular smooth muscle cell nuclie in the tunica media than did the control artery. These findings suggest that sympathetic innervation influences the proliferation of vascular smooth muscle in growing rabbits.


Effect of lidocaine and quinidine on steady-state characteristics and recovery kinetics of (dV/dt)max in guinea pig ventricular myocardium. We studied the effects of quinidine and lidocaine on the steady-state relationship between membrane potential and the maximum rate of rise of the action potential, (dV/dt)max, and on the recovery kinetics of (dV/dt)max in guinea pig papillary muscles. The steady-state relationships were determined in fibers stimulated at 0.2/sec and depolarized with KCl. Recovery kinetics were determined at various resting membrane potentials by assessing (dV/dt)max in progressively earlier premature action potentials. Lidocaine caused a dose-dependent decrease in (dV/dt)max, shifted the curve defining the steady-state relationship along the voltage axis in the direction of more negative potentials, and slowed the recovery kinetics of (dV/dt)max. Quinidine caused a dose-dependent decrease in (dV/dt)max but did not alter the shape of the curves defining either the steady-state relationship or the recovery kinetics of (dV/dt)max. Both drugs depressed membrane responsiveness as determined in premature action potentials originating from incompletely repolarized fibers. Our study indicates that the mechanisms whereby quinidine and lidocaine influence (dV/dt)max are different. It is possible that this difference may underlie some of the differences in the clinical effects of these two drugs.


Des-1-Asp-angiotensin II. Possible intrarenal role in homeostasis in the dog. The relative effects of des-a-Asp-angiotensin 3I and angiotensin II on renal function, including renin secretion, were investigated in normal and sodium-depleted dogs. Intrarenal arterial infusion of the heptapeptide fragment into normal dogs at a rate which was calculated to increase blood levels by only 7 ng/100 ml decreased renal blood flow from 254 +/- 9 ml/min to 220 +/- 12 and 219 +/- 12 ml/min (P less than 0.01 for both values) after 10 and 30 minutes of infusion, respectively; renin secretion decreased from 502 +/- 214 ng/min to 253 +/- 109 and 180 +/- 53 ng/min (P less than 0.05 for both values). Infusion of angiotensin II at the same rate decreased renal blood flow from 251 +/- 26 ml/min to 224 +/- 22 and 220 +/- 16 ml/min (P less than 0.01 and 0.025, respectively) and decreased renin secretion from 374 +/- 25 ng/min to 166 +/- 76 and 131 +/- 37 ng/min (P less than 0.025 for both values). Neither peptide significantly changed mean arterial blood pressure, creatinine clearance, or excreted sodium in these dogs. Infusion of des-1-Asp-angiotensin II into sodium-depleted dogs decreased renin secretion from 1094 +/- 211 ng/min to 768 +/- 132 and 499 +/- 31 ng/min (P less than 0.025 for both values) after 10 and 30 minutes of infusion. Angiotensin II infusion decreased renin secretion from 1102 +/- 134 to 495 +/- 235 and 502 +/- 129 ng/min in these dogs (P less than 0.05 and 0.025, respectively). Neither peptide significantly altered renal blood flow, arterial blood pressure, creatinine clearance, or excreted sodium in the sodium-depleted dogs. The data demonstrated that these two peptides have similar effects on the renin secretory mechanism and the vascular receptor at the level of the renal arterioles.


Radioiodinated soluble canine fibrin. Preparation and evaluation as a thrombus localizing agent in the dog. To develop a thrombus localizing tracer which has characteristics superior to labeled fibrinogen for external detection, we evaluated radioiodinated soluble fibrin. Labeled soluble fibrin was prepared by clotting and dissolving radioiodinated (131I) canine fibrinogen under specified conditions. Biological clearance studies revealed rapid clearance of the labeled soluble fibrin from the blood with a half-life of 5 hours. The accumulation of labeled soluble fibrin and fibrinogen in induced venous thrombi, coronary artery thrombi, and the myocardium was compared in dogs. In venous thrombi, soluble fibrin and fibrinogen exhibited maximum thrombus-blood ratios when they were injected 4 hours after thrombus induction; the thrombus-blood ratio was greater for soluble fibrin than it was for fibrinogen when these agents were injected 4, 8, or 24 hours after thrombosis induction. In induced coronary artery thrombi, soluble fibrin and fibrinogen accumulated to the same extent. Since the blood clearance of soluble fibrin is faster than that of fibrinogen, a higher thrombus-blood ratio was obtained with soluble fibrin in coronary artery thrombi. The thrombus-infarcted myocardium, thrombus-normal myocardium, and infarcted myocardium-normal myocardium ratios obtained with soluble fibrin were slightly higher than those obtained with fibrinogen. Thus, soluble fibrin offers some advantages when it is compared with fibrinogen as a thrombus detecting agent.


Reflex heart rate control via specific aortic nerve afferents in the rabbit. Reflex bradycardia was elicited in rabbits via repetitive electrical stimulation of the central end of the sectioned left aortic nerve. Supramaximal stimulation produced a 16.9 plus or minus 1.3% (SE) increase in the R-R interval when vagal and sympathetic efferent pathways were intact. Reducing the stimulation voltage allowed selective stimulation of the myelinated (A) fibers, and polarizing electrodes placed central to the stimulus site permitted A fiber blockade and selective stimulation of the unmyelinated (C) fibers. When afferent A fibers were selectively stimulated, 64% of the maximum response was obtained; selective C fiber activation elicited 63% of the maximum observed response. Selective stimulation of A or C fibers after either vagotomy or stellectomy indicated that A fiber afferents elicit heart rate responses via both vagal and sympathetic efferents, whereas C fiber afferent information is mediated predominantly via vagal efferents. This afferent-efferent specificity of the aortic baroreceptor pathways suggests baroreceptor mechanisms normally used to modulate heart rate. Small increments in blood pressure would activate low-threshold A fibers and result in reciprocal changes in vagal and sympathetic efferent activity. More substantial increases in blood pressure would activate afferent C fibers and produce additional heart rate effects via vagal efferents.


Control of aldosterone secretion in the spontaneously hypertensive rat. Adrenal secretion rates of aldosterone, corticosterone, and deoxycorticosterone were studied sequentially in the spontaneously hypertensive rat and the normotensive Kyoto Wistar rat. Steroid secretion was studied at three different ages: 7-8, 11-13, and 22-25 weeks. Also, peripheral plasma levels of aldosterone and plasma renin activity were determined in both the spontaneously hypertensive and the normotensive rats at 7-8 weeks of age. Aldosterone secretion was elevated markedly in dexamethasone-morphine-treated spontaneously hypertensive rats at both 7-8 and 11-13 weeks of age but was not significantly different from control in 22-25-week-old spontaneously hypertensive rats. No statistically significant differences in corticosterone or deoxycorticosterone secretion rates were observed between the spontaneously hypertensive rats and the normotensive Kyoto Wistar controls; however, the data suggested that dexamethasone did not suppress adrenocorticotropic hormone in the 7-8- and 11-13-week-old spontaneously hypertensive rats to the same extent that it did in the normotensive Kyoto Wistar rats. Therefore, aldosterone secretion was reexamined in acutely hypophysectomized 7-8-week-old rats to eliminate completely the influence of the anterior pituitary; no differences in aldosterone, corticosterone, or deoxycorticosterone secretion rates were observed between hypophysectomized spontaneously hypertensive rats and normotensive Kyoto Wistar rats. Moreover, aldosterone secretion in the hypophysectomized 7-8-week-old spontaneously hypertensive rats was reduced markedly compared with that in the intact 7-8-week old spontaneously hypertensive rats, thus confirming the importance of the pituitary in these animals. Determinations of peripheral plasma aldosterone concentration and plasma renin activity in unstressed 7-8-week-old spontaneously hypertensive and normotensive rats revealed that both parameters were depressed significantly in the spontaneously hypertensive rats. Thus, the present data indicate that the renin-angiotensin-aldosterone system is suppressed in the spontaneously hypertensive rat but do not suggest that the system is critically involved in the hypertensive process in these animals


Vascular angiotensin II receptors and sodium balance in rats. Role of kidneys and vascular renin activity. The relationship between the vascular response. to angiotensin II and sodium balance was studied by measuring the volume of specific antiserum needed to block the pressor response to a standard dose of angiotensin II in rats. In normal rats, sodium depletion reduced the volume of antiserum required to prevent a pressor response to 50 ng of angiotensin II from 0.32 to 0.22 ml; sodium loading increased the volume required to 0.65 ml. After bilateral nephrectomy, there was a progressive increase in the antibody requirement to a maximum of 0.63 ml at 6 hours. At this stage, there was no change in the blocking requirement with sodium depletion by either pretreatment with a low-salt diet (0.60 ml) or peritoneal dialysis (0.62 ml). The pressor response to a 50-ng bolus of angiotensin II was closely correlated with the antibody requirement in all experiments (r equals plus 0.93). These observations indicate that sodium-induced changes in the vascular response to angiotensin II require the presence of kidney tissue. We suggest that such changes in response are mediated by alterations in vascular renin which generates angiotensin II at an arteriolar site that is not accessible to antibody molecules. This locally formed angiotensin II reduces the number of receptors free to respond to circulating angiotensin II and raises the threshold of the pressor response


The sequence of retrograde atrial activation in the canine heart. Correlation with positive and negative retrograde P waves. The relationship of P-wave polarity and morphology in leads II, III, and aVF to the sequence of atrial activation was studied in the canine heart when the atria were paced from the region of the sinus node or the posterior-inferior left atrium and when retrograde activation of the atria occurred with right ventricular epicardial pacing. Deeply negative P waves in leads II, III, and aVF which occurred when the posterior-inferior left atrium was paced were associated with true retrograde activation of the atria. Positive P waves recorded in leads II, III, and aVF during retrograde atrial capture with right ventricular pacing were associated with rapid retrograde spread of the impulse in the interatrial septum to the region of Bachmann's bundle from which site the impulse spread to depolarize significant portions of both atria in a manner similar to that demonstrated during pacing from the region of the sinus node. When the atria were paced from a site just anterior to the coronary sinus ostium, positive P waves recorded in leads II, III, and aVF were associated with early activation in the vicinity of Bachmann's bundle and later activation of the posterior-inferior left atrium. When the atria were paced from a site just posterior to the coronary sinus ostium, negative P waves in leads II, III, and aVF were associated with early activation of the posterior-inferior left atrium and later activation in the vicinity of Bachmann's bundle. It was concluded that the time of arrival of the impulse at Bachmann's bundle relative to that at the posterior left atrium and the direction of spread of the impulse from and within Bachmann's bundle are critical in determining P-wave polarity and morphology.