Intrahemispheric cortical connexions and visual guidance of hand and finger movements in the rhusus monkey. An attempt has been made to elucidate in the rhesus monkey the role of intrahemispheric cortico-cortical connexions in visual guidance of relatively independent hand and finger movements which are governed mainly from the precentral motor cortex. These movements were tested by requiring the animals to retrieve with their fingers small food pellets from a special test board in which the pellets were easily visible but were more difficult to palpate. Unilateral occipital lobectomy combined with a commissurotomy impaired the performance of the contralateral hand. The same was true for the parietal leucotomy of Myers et al. (1962) which transects the bulk of the intrahemispheric occipitofrontal cortical fibres. Tests of the visual discrimination of the leucotomized hemispheric showed that the motor impairment after this leucotomy did not represent a visual defect. In control animals no impairment was found after ablation of the cortex on the surface of the postcentral gyrus and the superior parietal lobule. A mild impairment occurred, however, when the lesion either involved also the inferior parietal lobule or was accompanied by a white matter infarct deep under the postcentral gyrus. The findings make it likely that the intrahemispheric cortical fibres to the frontal lobe play a role in visual guidance of relatively independent hand and finger movements. This conclusion is also supported by some preliminary findings after frontal lobe lesions, but further experiments are necessary to establish it firmly.


Visual evoked responses in the diagnosis and management of patients suspected of multiple sclerosis. Averaged visual evoked responses to pattern reversal stimuli have been recorded in 54 control subjects, 51 patients with multiple sclerosis, and 55 patients with other neurological diseases which might involve the visual apparatus. The latency to the peak of the major positive potential in normal subjects under the age of 60 was 104 msec or less (mean 90-5 msec+3 SD). The latency of the VER was prolonged above this value in one or both eyes in 67 per cent of the patients with multiple sclerosis (in 84 per cent of those with definite multiple sclerosis, in 83 per cent of those with probable multiple sclerosis, and in 21 per cent of those with possible multiple sclerosis). The latency of the VER was also prolonged in 25 percent of those with an acute spinal cord lesion of unknown cause; in 46  per cent of those with an isolated brain-stem lesion unknown cause; and in 49 per cent of patients presenting with a progressive spastic paraparesis. The extra delay in latency varied from a few msec to as much as a 100 msec. In patients with multiple sclerosis, a delayed VER was found in the affected eye in all with a previous history of optic neuritis, and in 47 per cent of those with no such history....


Use of the Pulfrich pendulum for detecting abnormal delay in the visual pathway in multiple sclerosis. (1) Pulfrich's pendulum has been developed as a method for detecting abnormal delay in the visual pathway of patients with suspected multiple sclerosis. (2) Forty-one normal subjects gave a mean interocular latency difference of 2-4 +/- 1-8 msec on Pulfrich's pendulum. This mean +2 SD (6 msec) was taken as the limit of normal interocular latency difference by this method. (3) The test was assessed on 58 patients. Eighteen of these had definite multiple sclerosis, 9 had probable multiple sclerosis, and 8 had possible multiple sclerosis, according to clinical criteria. The remaining 23 patients did not conform with clinical criteria for multiple sclerosis, and served as neurological controls. Thirteen of these 23 patients had abnormal signs in the visual system. All the 58 patients also had visual evoked responses (VERs) recorded. (4) Interocular latency difference was outside the normal range in 9/18 with definite multiple sclerosis, in 3/9 with probably multiple sclerosis and in 2/8 with possible multiple sclerosis. (5) Interocular latency difference was outside the normal range in 2/23 patients with other neurological disorders. (6) There was a strong correlation between abnormality on the Pulfrich pendulum and on the VER for the multiple sclerosis group. (7) Individual results are compared with those from the VER. There was no significant correlation of the size and direction of the interocular latency difference obtained from the Pulfrich pendulum with that obtained from the VER, for any group. Possible reasons for this are discussed. (8) It is concluded that Pulfrich's pendulum is an easily performed and potentially useful subjective test for detecting abnormal dealy in the visual pathway in multiple sclerosis.


The cerebral pathways of optokinetic nystagmus: a neuro-anatomical study. Abnormalities of optokinetic nystagmus are described in a patient with pathologically proven bilateral infarcts in the middle cerebral artery territories. There were no other central nervous system lesions. These abnormalities of eye movement are interpreted as indicating an inhibitory effect of the frontal eye fields upon the occipital lobes.


Vestibular dysfunction in hereditary ataxia. A kindred with a unique autosomal dominantly inherited ataxia of late onset is described. Manifestations of the condition include defective optokinetic nystagmus and absent or abnormal oculo-vestibular responses, in association with normal cochlear function. It is possible that these latter features may serve as "markers" to indicate the presence of the disease in presymptomatic young adults, thereby facilitating important genetic counseling.


Simple reaction time: evidence for focal impairment from lesions of the right hemisphere. Simple reaction time is significantly increased in patients with unilateral lesions of either cerebral hemisphere responding with the hand ipsilateral to the lesion, but the effect is much greater when the lesion is in the non-dominant hemisphere. This difference cannot be attributed to asymmetries in the size or type of lesion. It applies over the complete distribution of reaction times as well as to the means, and is not diminished by practice. Neither the classical conduction model of reaction time nor the mass-action hypothesis proposed by De Renzi and Faglioni (1965) can account for the findings. Although the increase of about 100 ms observed with lesions of the dominant hemisphere probably represents a non-specific effect of brain disease, the much larger increases resulting from lesions of the non-dominant hemisphere appear to be of focal origin. The critical areas cannot yet be specified with certainty, but maps of the brain scans for patients with the highest reaction times suggest that structures in or near the basal ganglia and the posterior parietal region of the non-dominant hemisphere are involved, and other studies show that the focal effect is not found when patients with contralateral motor involvement are excluded.


Timing of activity in cerebellar dentate nucleus and cerebral motor cortex during prompt volitional movement. The discharge of neurons in cerebellar dentate nucleus and cerebral motor cortex was recorded on alternate days in each of 3 monkeys in association with prompt arm movement in response to a light signal. The time of change of the discharge of each neuron in relation to arm movement was computed. The distributions of the time of change for cerebellum and cerebrum overlapped, but the cerebellar distribution was shifted slightly earlier.


The effects of lesions of the superior colliculus on locomotor orientation and the orienting reflex in the rat. The effects of bilateral removal of the superior colliculus or visual cortex on visually guided locomotor movements in rats performing a brightness discrimination task were investigated directly with the use of cine film. Rats with collicular lesions showed patterns of locomotion comparable to or more efficient than those of normal animals when approaching one of 5 small doors located at one end of a large open area. In contrast, animals with large but incomplete lesions of visual cortex were distinctly impaired in their visual control of approach responses to the same stimuli. On the other hand, rats with collicular damage showed no orienting reflex or evidence of distraction in the same task when novel visual or auditory stimuli were presented. However, both normal and visual-decorticate rats showed various components of the orienting reflex and disturbance in task performance when the same novel stimuli were presented. These results suggest that although the superior colliculus does not appear to be essential to the visual control of locomotor orientation, this midbrain structure might participate in the mediation of shifts in visual fixation and attention. Visual cortex, while contributing to visuospatial guidance of locomotor movements, might not play a significant role in the control and integration of the orienting reflex.


Influence of increasing doses of pentobarbital on the mesencephalic reticular formation in rats. Spontaneous firing of neuronal pairs and activity evoked by polarization. In rats immobilized by D-tubocurarine the spontaneous activity in pairs of mesencephalic reticular neurons was recorded by means of one microelectrode and differentiated by amplitude discriminators. Spontaneous activity of neuronal pairs and activity evoked by electrical polarization of cells (5-235 nA) through the recording microelectrode was evaluated in the curarized state and after cumulative doses of 15 mg/kg pentobarbital. No correlation between mean interspike interval duration in pairs of adjacent neurons was found in the unanesthetized state. After pentobarbital a slight dependence was observed between the values. Furthermore, it is probable that adjacent neurons will both cease firing at the same dose of pentobarbital. Cross-correlation of the spike trains of two adjacent neurons was found in the range of minus 10 msec to plus 10 msec (which is probably an expression of direct interaction or of a common input) in 6 of 50 pairs analyzed in the unanesthetized state. This dependence fully disappeared after 15-30 mg/kg of pentobarbital. After 15 mg/kg of pentobarbital in 17 recorded pairs (out of 50 analyzed) peaks in the cross-correlograms appeared in a range of about 100 msec and at a distance of 150-300 msec. Such a relationship was already present in 4 pairs of neurons in the unanesthetized state. The similarity of autocorrelation and cross-correlation histograms in this case favors the hypothesis that spontaneous activity of many mesencephalic reticular neurons is synchronized after pentobarbital administration. In many reticular neurons the firing may be evoked by direct cell polarization through the recording microelectrode even at cumulative doses of pentobarbital much higher than those sufficient to block spontaneous activity.


Isolation of an endogenous compound from the brain with pharmacological properties similar to morphine. This investigation was carried out to test the hypothesis that the brain contains a substance that functions as an endogenous mediator at central morphine receptor sites. The extraction and purification of a low molecular weight substance are described. This substance inhibits neurally evoked contractions of the mouse vas deferens and guinea pig myenteric plexus. The inhibitory action of this substance was antagonized by the 3 narcotic antagonists naloxone, naltrexone and MR 1302 at nanomolar concentrations. The narcotic antagonists alone had no effect on the assay tissues. The purified substance had no effect on the guinea pig or rabbit vas deferens, tissues which do not possess morphine receptor sites. The pharmacological activity of the substance is destroyed by carboxypeptidase and leucine aminopeptidase, it is hydrophilic and behaves as an ampholyte in ion exchange systems. These observations and the production of ninhydrin positive products on acid hydrolysis indicate the presence of a small molecular weight (less than 700) peptide. The morphine-like substance was unevenly distributed in the brain, the highest concentrations occurring in the striatum, midbrain, pons and medulla. No activity could be detected in extracts of cerebellum, liver or lung. It is suggested that the compound isolated in this investigation forms part of a central pain suppressive system and may also have a wider neurochemical role in the brain.


An electrophysiological examination of the changes in skeletal muscle fibres in response to degenerating nerve tissue. Endplate free areas of the emebrane of soleus and extensor digitorum longus muscles of the rat, covered fpor 3 days by a piece of nerve from the brachial region, become locally sensitive to ACh applied iontophoretically. Mean ACh sensitivity is increased at this site in the extensor muscle from 0 in areas not covered by the nerve to 6.27 mV/nanocoulombs (nC) +/- 1.28 (S.E.), in the area under the nerve and in soleus from 0.12 mV/nC +/- 0.05 (S.E.) to 24.2 mV/nC +/- 4.6 (S.E.). Increase in sensitivity is accompained by a decrease of resting membrane potential. Mean values are (unaffected areas) 75.0 mV +/- 0.55 (S.E.) to (affected area) 65.0 mV +/- 0.56 (S.E.) in soleus and (unaffected areas) 76.3 mV +/- 0.61 (S.E.) to (affected area) 67.0 mV +/- 0.55 (S.E.) in extensor digitorum longus. These changes are local in individual fibres. Changes in ACh sensitivity and resting membrane potential in the area covered by the nerve are temporary, and after 6 days no sign of increase in sensitivity and drop in membrane potential were observed. The piece of nerve loses its potential to induce AHh sensitivity when it is heated to 98 degrees C for 5 min or soaked for 2 h in distilled water.


Retrograde cortical aand axonal changes following lesions of the pyramidal tract. Following lesions of the pyramidal tract in hamsters, retrograde changes were studied in the sensorimotor cortex and in the pyramidal tract axons proximal to the lesion, at survival times ranging from 2 weeks to 14 months. Severe cell shrinkage occurred in layer 5 pyramidal neurons as early as 2 weeks, but there was no cell loss among these neurons even with long survival times. Use of the Fink-Heimer method for degenerating axons revealed that the pyramidal tract proximal to the lesion had undergone a retrograde axon degeneration which, in some respects, resembled anterograde degeneration. The retrograde axon degeneration began at the lesion site and advanced slowly rostralwards with time involving increasingly greater numbers of fibers. However, even at the longest survival times the degeneration fell off markedly at pontine levels. The results indicate that this process represents a true retrograde fiber degeneration (as opposed to an indirect Wallerian degeneration) which appears to reach a point of equilibrium such that a partially shrunken pyramidal cell is maintaining a partially degenerated axon.


Quantitative data on cell loss and cellular atrophy of intralaminar nuclei following cortical and subcortical lesions. Morphological changes in the intralaminar nuclei centralis medialis, paracentralis and centralis lateralis of the thalamus of adult cats after cortical excisions have been determined by means of a quantitative method. The number and size of the remaining neurons on the operated side have been compared with those of the normal side. The differences between the normal and the operated side have been compared to those found between the two sides in the control animals. The most important result is the demonstration that after cortical ablations the intralaminar nuclei show not only chromatolytic or atrophic changes of their cells but also a true cell loss. These reactions are qualitatively similar to those observed in the specific nuclei of the thalamus, the only difference being a quantitative one. As a consequence it can be suggested that some intralaminar nuclei project to certain areas of the cerebral cortex which also receive projections from one or other specific thalamic nucleus. A large essential connection of the intralaminar nuclei, in particular the nucleus centralis medialis, with subcortical structures is confirmed.


Radioautographic study of the rat brain after injection of [1,2-3H]corticosterone. Cryostat sections of the central nervous system of adrenalectomized male rats injected with [3H]corticosterone were examined by radioautography. One hour after the injection, radioactivity was found to be selectively concentrated in specific neurons of the septum, the hippocampal complex (precommissural hippocampus, cornu Ammonis, gyrus dentatus, subiculum), the indusium griseum, the amygdala and in certain areas of the cortex. In the hippocampus, the pyramidal neurons in fields CA1 and CA2 of the cornu Ammonis and the granule neurons of the gyrus dentatus contained more radioactivity than did other regions of the brain. Most of the silver grains were localized in the nuclei of labeled cells. The topographic distribution of corticosterone-concentrating neurons shows that the hormonal target sites in the central nervous system are mainly extrahypothalamic.


Appearance of myelin proteins in rat sciatic nerve during development. Rats between 5 and 45 days of age were sacrificed and their sciatic nerves dissected. Myelin was prepared from these sciatic nerves by a procedure involving purification on discontinuous sucrose gradients. The proteins of whole sciatic nerves at different ages and the proteins derived from the myelin isolated from these sciatic nerves were examined by discontinuous polyacrylamide gel electrophoresis in buffers containing sodium dodecyl sulfate. Over half of the proteins of sciatic nerve myelin migrated in a single band on the gel (P0). There were only minor changes in the protein distribution of sciatic nerve mylein during development. In contrast, the polyacrylamide gel patterns of whole sciatic nerve homogenate changed markedly during development between 5 and 15 days of age. The amount of P0 protein as a proportion of the total sciatic nerve protein increased from 3% at 5 days of age to 13% at 15 days of age after which it remained constant. Several other proteins which were also characteristic of the isolated myelin increased in relative importance during this time period. Parallel experiments dealing with a metabolic parameter of myelinogenesis, incorporation of intraperitoneally injected [35S]sulfate into sulfatide, were conducted. The maximum synthesis of sulfatide occurred between 6 and 16 days of age, coincident with the marked accumulation of myelin proteins in sciatic nerve.


[A microphysiologic study of thalamic projection of the cat's dental pulp (author's transl)]. (1) A similar proportion of cells in the VPM (24.7%), MGmc (24%), CM (26.8%) and CL (28.6%) is activated by electrical stimulation of the cat's dental pulp. However the thresholds are very different, cells belonging to the first group of the VPM being often activated by stimulation below 0.1 V. (2) Pain seems to be the unique sensation evoked by pulpal stimulation. A first group of cells somatotopically localized in the VPM displays a primary type of response. These cells can also be activated from an oral or perioral field. This fact is reminiscent of referred pain phenomenon often encountered in the clinic. (3) A second group of cells scattered in the VPM and activated by pulpal stimulation displays a non-primary type of response. (4) Strong pinching of the skin activates some MGmc cells tonically. Response characteristics of the MGmc cells after pulpal stimulation are heterogeneojs. (5) CM cells activated by pulpal stimulation display long latency responses whose properties are similar to those obtained after somatic stimulation. However, the latency of responses are shorter after limb stimulation than after pulpal stimulation.


Amino acid uptake in vivo by the mouse brain and by various regions of the rabbit brain after drug-induced convulsions. The levels of the free amino acids of the mouse brain were studied after convulsions induced by Metrazol; a decrease of level of taurine and a significant increase of level of alanine, phenylalanine and isoleucine were found. The net uptake of L-histidine by the mouse brain in vivo was similar under normal conditions and after Metrazol-induced generalized convulsions; that of L-methionine was much higher after convulsions and there was no uptake of L-aspartic acid, either under physiological conditions or after convulsions. The net uptake of L-histidine by various regions of the rabbit brain in vivo after convulsions was significantly higher than control values in the cortical areas, while that of L-methionine was significantly higher in the subcortical ones; there was no uptake of L-aspartic acid by the rabbit brain in normal condition, whereas after convulsions a small entry seemed to occur in the subcortical areas. These results indicate that cerebral permeability processes of amino acids are somewhat altered during convulsive phenomena, as already described elsewhere for ions andproteins.


Effects of two estradiol antagonists upon the estradiol uptake in the rat brain and peripheral tissues. Two estradiol antagonists, Parke-Davis CI 628 and CI 680, were studied for their inhibitory potency against labeled estradiol uptake within the hypothalamus, cerebral cortex, pituitary and uterus of the ovariectomized rat. Both drugs, tested from 15 min to 24 h prior to estradiol, induced a fast and long-lasting decrease of the hormone uptake. Three degrees of inhibition were observed depending on the tissue studied: (a) the most important inhibition concerned uterus and pituitary, where the estradiol uptake was prevented by up to 90% by the largest doses of antagonists used (6.3 and 6.1 mg, respectively, for CI 268 and CI 680); (b) in the hypothalamus, the estradiol uptake was counteracted to a lower degree; the inhibition being 39% for anterior hypothalamus and 22% for medial posterior hypothalamus; (c) cerebral cortex uptake was completely unaffected by pretreatments with the antagonists. After subcellular fractionation it was observed that the nuclear uptake of estradiol was completely abolished in both hypophyseal and hypothalamic tissues if the hormonal injection was preceded by the administration of 6.3 mg of CI 628.


The action of thiamine and its di- and triphosphates on the slow exponential decline of the ionic currents in the node of Ranvier. Sodium and potassium currents in the node of Ranvier decrease exponentially with time during long lasting voltage clamp experiments. This decline is strongly dependent on temperature (Q10 approximately 3). Thiamine and, particularly, its diand triphosphoric acid esters are shown to prevent this exponential decline of the ionic currents. Thiamine acts from the outside and from the inside of the nodal membrane, but more potently from the inside. Thiamine diphosphate prevents the exponential decline of the ionic currents only when applied internally. Thiamine triphosphate, the most effective thiamine derivative was tested form the inside only. Bacterial thiaminases applied externally were not effective, presumably because they do not permeate the nodal membrane. Tetrodotoxin, that has been shown by other investigators to induce a release of thiamine from nerve membranes, does not alter the action of thiamine on the exponential decline of current and vice versa. It is concluded that: (1) thiamine diphosphate or thiamine triphosphate are the active thiamine compounds in nerve membranes; (2) the site of action is located at the internal suface of the membrane; (3) the reduction of the thiamine concentration in the membrane or in the axoplasm could cause the exponetial decline of currents; (4) the release of thiamine from nerve membranes induced by tetrodotoxin is interpreted as a side effect not even related to the mechanism by which tetrodotoxin blocks the sodium channels; (5) thiamine polyphosphates appear to stabilise the intrinsic electric field strength of the nodal membrane in the resing state. Threfore, as a working hypothesis, it is suggested that the thiamine derivatives control the number of functioning ionic channels by stabilising the density of negative surface charges at the inner side of the nerve membrane.


Behavioral effects of selective midbrain raphe lesions in the rat. Lesions were produced in the median (n = 8), dorsal (n = 7) or both (n = 7) midbrain raphe nuclei and their effects on behavior (days 16-54 postoperatively) compared to that of controls (n = 9). In addition, forebrain 5-hydroxytryptamine (5-HT) concentration were determined. Only the median and combined lesion groups showed increased running wheel and open field activity, as well as enhanced reactivity to novel stimuli and environmental change. None of the lesion groups, however, showed changes in home cage activity on postoperative day 21. Although all lesion groups were deficient in the acquisition and retention of one-way avoidance, the deficits were of a greater magnitude in the median and combined lesion groups. The latter two groups, furthermore, were impaired in forced extinction of the one-way avoidance response, but only the combined lesion group evidenced facilitation of two-way avoidance acquistion. Thus, in contrast to the effects of median or combined raphe lesions, lesions in the dorsal raphe nucleus affected few of the behavioral parameters studied. These results suggest that the dorsal raphe nucleus plays a different behavioral role than the median raphe nucleus. The median nucleus appears to be involved in the regulation of activity level, the reaction to novelty and environmental change, and the response to aversive stimuli. Possible mechanisms for the observed behavioral changes are discussed, as well as their apparent similarity to the effects of other mesencephalic and limbic lesions. Lastly, the median, dorsal and combined raphe lesions lowered forebraine 5-HT but 26, 65, and 77%, respectively, versus controls. These reductions differed significantly from each other, and with previously reported data indicate that the dorsal raphe nucleus in the principal origin of forebrain 5-HT. It is suggested, furthermore, that the behavioral effects of midbrain raphe lesions are not due primarily to their associated reduction in forebrain 5-HT.


An electron microscope study of the red nucleus in the cat, with special reference to the quantitative analysis of the axosomatic synapses. The synaptic organization of the red nucleus in the cat was investigated using the electron microscope and the axosomatic synapses were analyzed quantitatively using serial sections. The bouton covering ratios were found to be 61.5, 16.6 and 6.1% in large, medium-sized and small neurons, respectively. In a vast majority of axosomatic terminals, the synaptic apposition length ranged from 1.2 to 1.4 mum. There were 15-17 axon terminals on each 100 sq. mum of perikaryal surface of a magnocellular neuron. Seventy-four per cent of axosomatic terminals on the magnocellular neuron were filled with spherical vesicles and 22% had flattened vesicles. No clear correlation appears to exist between the shape of synaptic vesicles and the type of the postsynaptic differentiation. Somatic thorns were observed rather frequently on the magnocellular neurons. Axo-dendrodendritic serial synapses were occasionally observed to be present in the red nucleus. All postsynaptic components of these serial synapses contained pleomorphic vesicles. The possible existence of the Golgi type II cells in the red nucleus is discussed in relation to the components consituting the serial synapses.


Medial and lateral hypothalamic oxygen consumption as a function of age, starvation and glucose administration in rats. In fed rats, in vitro oxygen consumption of the ventromedial hypothalamus (VMH) was found to be reliably higher than that of the lateral hypothalamus (LHA), and this differential effect was abolished by prior food deprivation. Neither body weight (236-569 g) nor age (50-180 days old) was important in determining the magnitude of differential respiration of these hypothalamic subareas. VMH respiration was found to be especially responsive to intragastric administration of glucose-oxygen consumption increasing 94% above baseline levels in VMH, with only a 28% increment occurring in the LHA. Using various delays between loading of glucose and testing, the VMH-LHA ratio in oxygen consumption was found to be inversely related to food intake. Implications of these findings to the nature of hypothalamic control of feeding are discussed.


Separation of multi-unit nerve impulse trains by a multi-channel linear filter algorithm. We have applied a technique involving multi-channel linear filtering to the problem of sorting and identifying singly unit neuronal activity in records containing several simultaneously active units. The technique is effective even when the waveforms of two or more nerve impulses are superimposed. We have applied it successfully to data involving up to 6 units, and in theory it is applicable to substantially more. Current limitations are that the waveform of the impulse from each unit must first be determined by identifying and averaging several isolated examples, and that the number of recording electrodes must approximate the number of units present.


Anatomical, physiological and biochemical studies of the cerebellum from mutant mice. II. Morphological study of cerebellar cortical neurons and circuits in the weaver mouse. The vermis of the homozygous weaver mice has been examined with Golgi and electron microscopic techniques. In addition to the findings already reported by previous authors 12, 29, new cytological features concerning all the cerebellar neuronal types and the synaptic reorganization of the cerebellar circuitry are described. As in other agranular cerebella, Purkinje cells do not develop spiny branchlets and have a randomly oriented dendritic tree. By contrast, their thick dendrites are studded with spines; according to their size and shape these were classified into: (a) small stubby spines which are the normal postsynaptic targets for climbing fibers; (b) tertiary-like spines, most of which are free of axonal contacts; (c) dolichoderus spines; (d) branching spines; and (e) hypertrophic spines. The last 3 types do not exist in normal cerebellum. Postsynaptic-like differentiations are frequently undercoating the smooth surface of the Purkinje dendrites. As it happens in the case of the free spines, free postsynaptic sites in the shafts of the dendrites develop an extracellular material similar to the material present in synaptic clefts. Basket and stellate cells also develop postsynaptic-like differentiations undercoating the somatic and dendritic plasma membranes. These free postsynaptic sites can reach a gigantic size, being longer than 3 mum in length. The rare postmigrative granule cells which persist in wv exhibit claw-endings not only at the dendritc terminal segments, but at the proximal dendritic stems as well. Some of these granule cells, besides having fully achieved migration, undergo a degenerative process indicating that they are probably directly affected by the mutation. Concerning the cerebellar circuitry, and despite the great number of free postsynaptic sites, the large majority of the synaptic contacts keep their specificity. However, some quantitative variations have been disclosed. The surface density of climbing varicosities is increased, whereas that of mossy rosettes is decreased. Stellate and basket fibers are present and their density also decreased. Furthermore, the pinceau formation around the initial segment of the Purkinje cell axon is missing. In addition to all normal synapt iccontacts (with the exception of the'parallel fiber-omnicellularsystem') present in weaver, heterologous synapses have also been encountered, mainly concerning the Purkinje dendritic spines, which can be contacted by mossy rosettes, granule cell bodies and/or dendrites. Morphological signs of partial innervation of the free postsynaptic sites on the smooth surface of Purknje dendrites and the perikarya and dendrites of interneurons have also been observed. These results confirm the existence of synaptic remodeling in wv cerebellum


Dopamine and norepinephrine levels in the nucleus accumbens, olfactory tubercle and corpus striatum following lesions in the ventral tegmentalarea. Dopamine and norepinephrine levels were examined in 3 forebrain regions following unilateral lesions either in the ventral medial tegmental area (VMT) or in the substantia nigra. The dopamine and norepinephrine content of the nucleus accumbens, olfactory tubercle and corpus striatum were assayed ipsilaterally and contralaterally in unilaterally lesioned rats sacrificed 2, 5, 10, and 20 days after the placement of the lesions. In the nucleus accumbens and olfactory tubercle ipsilateral dopamine levels were significantly reduced below the contralateral levels at 2 days, and were decreased by 56% and 65%, respectively, 10 days after the lesion. A 30% reduction of dopamine levels occurred in corpus striatum as well, following lesions in the VMT. Lesions in the substantia nigra decreased ipsilateral dopamine levels by 68% in the corpus striatum, without affecting dopamine levels in the olfactory tubercle or nucleus accumbens. Norepinephrine levels on the side ipsilateral to the lesion did not significantly differ from contralateral levels in any of the 3 regions following lesions either in the VMT or in the substantia nigra. These results demonstrate the specificity of projection in the mesolimbic dopamine system as suggested by the original histofluorescence studies.


Lysergic acid diethylamide: evidence for stimulation of cerebral dopamine receptors. In the rat, lysergic acid diethylamide (LSD) decreased the striatal and retinal content of homovanillic acid. LSD did not change the level of dopamine (DA), but delayed the a-methyl-p-tyrosine-induced disappearance of this amine in the teldiencephalon. In the cat, LSD diminished the DA output into the perfusate of the caudate nucleus. Furthermore, LSD increased the activity of adenylate cyclase in striatal homogenates of rat. These and other findings indicate that in the central nervous system LSD stimulates DA receptors which may be involved in LSD-induced phychosis.


The metabolic clearance rate, head and brain extractions, and brain distribution and metabolism of progesterone in the anesthetized, female monkey (Macaca mulatta). The brain distribution and metabolism of progesterone were studied in female, rhesus monkeys. Adult monkeys were anesthetized with ketamine and were given a constant infusion of [3H]- or [14C] progesterone. Blood samples were obtained from cannulae inserted into the carotid artery, the jugular vein and lateral (transverse) sinus. The metabolic clearance rate of progesterone was 295 +/- 49 (S.E.) 1/day. The head extraction of progesterone was 30.4 +/- 8.3% (S.E.) and the brain extraction 26.0 +/- 9.18% (S.E.). The peripheral conversion ratios of progesterone to 20alpha-hydroxypregn-4-en-3-one (20alpha-OHP) and 5alpha-pregnan-3,20-dione (5alpha-DHP) were 10.0 +/- 1.3% (S.E.) and 2.4 +/- 0.3% (S.E.), respectively. These same conversion ratios for across the head were 4.8 +/- 1.0% (S.E.) and 1.5 +/- 0.6% (S.E.) and for across the brain 5.0 +/- 0.7% (S.E.) and 2.2 +/- 0.6% (S.E.). The concentration of radioactive progesterone was 2-5 times higher in brain tissues compared to the carotid arterial blood. The tissue concentrations of radioactive progesterone compared to a cerebrum 'control' sample: was lower in the central gray (P less than 0.05); were the same for the amygdala, hippocampus, preoptic-anterior hypothalamus, cerebellum, hypothalamus, thalamus, and anterior pituitary; and were higher in the cervical spinal cord, optic chiasm, mesencephalon, medulla oblongata and pons (P less than 0.1). The distribution pattern of 20alpha-OHP formed from progesterone was similar to that of progesterone. 5alpha-DHP formed from progesterone had a different distribution than progesterone, being highest in the central gray area. High concentrations of 5alpha-DHP were also observed in the mesencephalon, medulla oblongata and hypothalamus and low values in the anterior pituitary. Infusions of [3H]20alpha-OHP and [3H]5alpha-DHP were used to evaluate the in vivo metabolism of progesterone by different brain areas. [3H]Estradiol infused into one monkey had its highest concentration in the anterior pituitary which was 20 times higher than in the carotid arterial blood.


Submicroscopic changes of cortex nerve cells in chronic mirror epileptic focus in rats. Submicroscopic changes of neurons, synapses, glial cells and some elements of capillaries were established by studying chronic mirror foci which appeared in the rat cerebral cortex after implantation of cobalt-gelatinous rods into the contralateral hemisphere. The results were compared with normal control cortex and with changes after thermocoagulation of the symmetrical contralateral cortex. It is shown that epileptogenic lesions produce a significant reduction of RNA-components, edema and vacuolization of neuronal cytoplasm, hypertrophy and proliferation of glial cells. The revealed pathological changes of the synapses were manifested by dilatation of some vesicles and the appearance of heterogenic inclusions. The characteristic features of Wallerian degeneration of callosal synapses and the reversible retrograde changes of the neurons which send their axons into the traumatized zone of the contralateral hemisphere were observed to be similar after both experimental lesions.


Electrically-induced epileptogenesis in rabbit olfactory bulb: electrophysiological plasticity in a simple cortical system. Sustained seizure activity can be induced in rabbit olfactory bulb by application of brief low-level current via chronically implanted micro-electrodes.  Sensitivity to such stimulation is markedly augmented by prior surgical isolation of the ipsilateral or contralateral bulb.  The isolated rabbit olfactory bulb apparently possesses an intrinsic system sufficient to acquire and retain altered neuronal excitability of an epileptiform kind.  The preparation described here offers promise as a model for further studies of electrophysiological plasticity in a simple cortical system.


Two generators of hippocampal theta activity in rabbits. Spontaneous and hypothalamically induced theta activity was studied in rabbits lightly anaesthetized with urethane or urethane-chloralose.  Well-developed theta activity was found over a large area of the dorsal part of the hippocampal formation, roughly corresponding to the CA1 field.  Cross-correlation analysis between a stationary and a moving electrode showed that a large sheet of tissue oscillated in remarkable synchrony.  This region was at least 8 mm along the longitudinal axis of the hippocampus and 6 mm in a plane transverse to this axis, thus comprising the whole of the rostro-caudal extension of the CA1 region.  For technical reasons the temporal half was not explored.  Depth recordings showed two foci of theta activity, one in the basal part of CA1 (stratum oriens) and a second, separate region with considerably larger amplitudes in the dentate region, having its maximum in the molecular layer.  Due to the folded nature of the dentate fascia, an electrode often recorded two maxima corresponding to its upper and lower blades.  Wave form analysis showed that the dentrate and CA1 rhythmic activity was roughly 180 degrees out of phase.  The dentate theta activity remained in conditions where the CA1 theta activity was absent, either spontaneously or due to experimental interference.  Systematic micro-electrode tracking showed absence of theta activity in the CA3 region.  Nor was convincing theta activity found in the subiculum, parasubiculum, presubiculum or entohinal areas.


Short- and long-term effects of nerve growth factor on the sympathetic nervous system in the adult mouse. Nerve growth factor (NGF) induced a marked increase in the adrenergic nerve terminal networks of several peripheral organs in intact adult and young adult mice.  The animals were investigated at 3 days and at 2 months after 6 daily subcutaneous injections of the 7S species of NGF (1 mug/g body weight each dose).  At 3 days after the end of the treatment an increased fluorescence intensity, as well as an increased density of the adrenergic terminal plexuses was observed by fluorescence histochemical techniques in iris, salivary glands, heart, intestine, spleen and pancreas.  These changes were paralleled by significant increases (up to 55%) in the endogenous NA levels.  Increased NA levels were also detected in the brain of the NGF-treated animals.  At 2 months after treatment the effects had almost totally disappeared, demonstrating that the NGF-induced overgrowth of the sympathetic axons was only temporary.  The increased adrenergic innervation probably resulted from a stimulatory effect of NGF on collateral sprouting from the intact adrenergic axons.  In line with the idea that the terminals of peripheral axons are continuously renewed, it is suggested that endogenous NGF could play a regulatory role in such a continuous growth process of the fully developed, adult sympathetic nervous system, directed at the maintenance of an adequate adrenergic terminal network.


High affinity choline uptake: an early index of cholinergic innervation in rat brain. The uptake of [3H]choline was investigated in nuclei-free homogenates or crude synaptosomal fractions (P2) from rat brain under various stages of development.  A comparable sensitivity of uptake to treatment by hyposmotic shock suggested the involvement of synaptosomal populations in choline uptake in immature as well as in adult brains.  However, significant changes in the "apparent" Km for the high affinity transport system and quantitative differences in the Na ion requirement for maximal uptake at 0.43 muM choline concentration were found during development; facts which suggested a greater contribution of the low affinity system in the more immature brains.  Assuming that the uptake with high and low sensitivity to Na+ reduction reflected that via the high and low affinity system reslectively, we have attempted to obtain real Km values for the high affinity system.  These Km values changed less than those measured directly, suggesting that the affinity constant for the high affinity system does not change during development.  On these assumptions, the developmental changes of cholinergic synaptogenesis were examined in 5 distinct regions of the brain.  It was found that the synaptogenesis begins several days earlier than the increase of choline acetyltransferase (ChAc) level in the frontal cortex, the hippocampus, the superior colliculus and the cerebellum.  These regions may be included among the terminal-rich regions according to available evidence related to cholinergic systems.  On the other hand, synaptogenesis accompanied the concomitant ChAc increase in the striatum, where the cholinergic interneurons are present.  It is concluded that the increase of ChAc in the terminal-rich regions is delayed by the axoplasmic flow; therefore, the earlier index of cholinergic synaptogenesis in these regions is the high affinity uptake activity rather than the enzyme activity.


Recovery of pattern discrimination ability in rats receiving serial or one-stage visual cortex lesions. Two groups of 10 hooded rats were trained on a pattern discrimination between horizontal and vertical striped stimuli which were equated for contour-length and total luminous flux, and in which consistent local luminous flux cues were eliminated.  In one group of rats, visual cortex removals were performed in two stages with training between the operations.  Nine out of the 10 rats were able to relearn the pattern discrimination (median of 344 trials) after the completed bilateral visual cortex lesions in one stage.  In agreement with previous studies, none of these animals were able to relearn the discrimination after more than 10 times (550 trial limit) the trials required for original learning.  However, several rats with total one-stage lesions could relearn the pattern discrimination if very extended periods of training were given.


Partial Klüver-Bucy syndrome produced by destroying temporal neocortex or amygdala. The temporal neocortex was removed in 4 monkeys, and 5 received amygdala destruction.  Four control animals received skin and muscle incisions.  The monkeys were compared on a visual pattern discrimination task, a food-non-food discrimination, and a rating scale that measured agonistic and approach behavior.  Only the cortical lesion disrupted retention of the visual pattern task and neither lesion disrupted performance of the food-non-food task.  Both lesions produced oral behavior, increased reaction to stimuli and decreased emotionality.  Thus, the major symptoms of the Klüver-Bucy syndrome are produced by destroying either the temporal neocortex or the amygdala.


Bone growth in the neonatal rat. II. Biochemical aspects of bone mineral incorporation. Long bones and mandibles from neonatal rats were studied to characterize the mechanisms regulating their growth and to describe the patterns of bone mineral acquisition. Mineral uptake was determined by measuring the rates of incorporation of radioactive calcium (45Ca) into three metabolic pools within, or intimately surrounding, the bone. The incorporation into the pool of protein-bound calcium was low throughout the neonatal period, accounting for no more than 1% of the total calcium uptake during this period. The ionized calcium concentration, which was low throughout, increased at the time when formation of the mineral phase was found to be high. The largest fraction of the mineral, the complexed calcium, showed a gradually increasing rate of incorporation, lasting approximately until the age of weaning. The two bony tissues differed somewhat in the slopes at which the incorporation rates changed. From these studies of bone growth, it appears that the process of bone mineralization starts around the time of birth, gradually gains intensity and is maximal between approximately 10 and 18 days. It is speculated that the ionized calcium fraction may be the precursor of mineral formation.


Effects of ethanol on chicks in vivo and on chick embryo tibiae in organ culture. Hypocalcemia previously reported in rats and dogs following oral administration of ethanol may have been caused by a movement of calcium from blood to bone. This present study was undertaken to determine whether ethanol also causes hypocalcemia in chicks and to investigate the direct effects of ethanol on mineral accretion, glucose metabolism and growth of embryonic chick tibiae in an organ culture system. A high dose of ethanol (6 g/kg body wt) produced hypocalcemia, hypermagnesemia and an elevated hematocrit in chicks. Results in vitro were as follows: 1) 5 to 30 mul ethanol/ml medium produced dose-related increases in bone mineral from 58-440%; 2) lactate production was inhibited at all ethanol levels; 3) increased mineral accretion did not occur in ethanol-treated tibiae when iodoacetate was in the medium, but did occur in mechanically disrupted bones exposed to ethanol; and 4) the ethanol response in bone was directly related to the medium phosphate concentration. The results lead to the following conclusions: 1) ethanol has a direct stimulatory effect on bone mineral accretion and an inhibitory effect on bone glucose metabolism in vitro; 2) viable bone cells and an adequate phosphate supply are necessary for the ethanol response, but tissue integrity is not; and 3) the hypocalcemic effect of ethanol in vivo may at least partially result from ethanol-stimulated bone mineral deposition.


The effects of fluoride on the mineralization of embryonic chick tibiae in organ culture. The effects of various concentrations of fluoride on the mineralization of embryonic chich tibiae were studied in vitro. After 4 days incubation in medium with a physiological Ca x PO4 product (1.8 mM2), fluoride promoted a highly significant dose-related enhancement of bone mineralization. In experiments  where the medium Ca x PO4 product was varied by changing either Ca or PO4 while keeping the other constant at 1.8 mM, fluoried at 7.5 muM or at 100 muM affected bone mineralization differbntly at low and high products. At medium Ca x PO4 products below 3 mM2, fluoride significantly enhanced bone mineral deposition compared to paired control bones, while at products above 5 mM2, fluoride significantly inhibited bone mineralization. This dual effect of fluoride was observed in both live bones and bones metabolically inhibited by 1 mM iodoacetic acid. Comparison of the effects of fluoride on the mineralization of live and dead bones suggested that the effects are dependent on the cellular control of Ca x PO4 product in the bone extracellular fluid. These findings support the hypothesis that fluoride may play an important role in governing the rate of mineralization in growing bones.


Scanning electron microscopy and electron probe microanalysis of calcified alpha-elastin coacervates. The uptake of calcium and phosphorus from a serum calcification medium by coacervated alpha-elastin was studied by electron probe microanalysis and scanning electron microscopy. Calcium and phosphorus were bound by the coacervate in ratios similar to that of hydroxyapatite. A significant difference was observed in the secondary electron image of the coacercules from the serum during calcification of the coacervate.


Mineralization of elastin extracted from human aortic tissues. Elastin was isolated from human aortic tissues by extraction with formic acid. The aortas came from individuals of both sexes with ages ranging from 18 to 67 years. The elastin was treated to remove pre-existing nuclei for hydroxyapatite and mineralized in vitro by incubation in a solution metastable to hydroxyapatite. The results showed an increased rate of mineralization in vitro as the age of the individual from whom the aorta was obtained increased. The lag period in mineral formation seen with elastin samples obtained from individuals below the age 40, disappeared with older elastin. Amino-acid analysis of the elastin samples confirmed earlier results by indicating an increase in the more polar amino acids in the older elastin samples. Exposure of the extracted elastin samples to several proteolytic enzymes including elastase confirmed the identity of the material as elastin.


Further studies on the nature of fluid compartmentalization in chick calvaria. Labeled mannitol and polyethylene glycol (mol. wt. 4000), PEG, were used as space markers to estimate the fluid compartmentalization of calvaria taken from 3-5-day-old chicks. The mannitol results indicated that about 80% of the water in these bones is extracellular. Only a small fraction of this extracellular space was available to the diffusion of polyehtylene glycol. Adsorption studies in vitro and prior incubation of the tissues with hydrolytic enzymes indicated that the phenomenon of exclusion of PEG was primarily physical in nature. The polyethylene polymer is excluded from the water of hydration of the mineral phase. Apparently much of the extracellular water (two-thirds) of bone is in the form of crystal hydration.


The effect of thyroxine administration on intestinal calcium absorption and calcium binding protein activity in the chick. Thyroxine (T4) injected subcutaneously into 3-week-old chicks (30 mug/kg body weight daily for 8 days) reduced the absorption of calcium from in vivo ligated loops of duodenum and the duodenal calcium binding protein (CaBP) activity measured by the Chelex ion exchange method. Chicks fed either a commercial diet or an artificial diet containing 0.5% or 1.0% calcium showed similar response to treatment with T4. A significant effect of T4 on either calcium absorption of CaBP activity could not be demonstrated in chicks fed a high calcium diet (2.0%). The possible mechanisms of action of T4 on calcium absorption are discussed.


The composition of the insoluble collagenous matrix of bovine predentine. Predentine obtained from bovine teeth by microdissection was extracted with EDTA and tris-NaCl solutions. The insoluble residue consisted mainly of collagen and resembled dentine collagen in overall amino acid composition. The residue differed in containing no detectable phosphoprotein, a much larger amount of collagen hexose and more non-collagenous glycoprotein, the neutral sugar composition of which was determined. Differences were also observed in the contents of reducible collagen cross-links. Half of the total phosphorus found in the predentine could not be accounted for solely by hydroxyapatite. The remainder was partly soluble and dialysable.


Variations in the composition of developing rat incisor enamel. The developing enamel of rat incisors was dissected into a series of samples extending from the newly-formed partially-mineralised matrix to the mature.enamel.  Chemical analysis showed that, on a dry weight basis, the tissue achieved the composition of mature enamel well before the completion of mineral uptake.  The enamel at this stage was porous and relatively soft.  As more mineral was acquired, its hardness increased.  Throughout the developing region, the Ca:P ratio remained fairly constant, but the CO2:P and Mg:P ratios both decreased due, apparently, to dilution by an influx of relatively C02- and Mg-free mineral.


Aging effects on osteon remodeling.

Aging effects on osteon remodeling. Analysis of partial cross sections of 101 human tibiae indicated that osteon remodeling in the outer cortex is affected by age.  The frequency of resorption spaces remained constant throughout life suggesting no loss of osteoclast function with age.  However, the frequency of both forming osteons and osteons which were structurally complete but not completely mineralized increased with age.  This suggests that protein matrix synthesis by osteoblasts slows with age and that initial mineralization, possibly mediated by osteroblasts, and final mineralization, possibly mediated by osteocytes, becomes increasingly deficient with increasing age.  The frequency of osteons which have dense (sclerotic) inner lamellae decreases with age.  This supports a hypothesis that such lamellae are functional, perhaps representing a specialized, labile, mineral phase and that osteons having this feature become less frequent as part of the general degenerative changes associated with aging.


Chemical and morphologic alterations of rabbit bone induced by adriamycin. Long term, low dose administration of adriamycin (ADR) to young growing rabbits resulted in significant alterations in bone structure and chemistry. Morphologic changes were most pronounced at epiphyseal and metaphyseal areas of long bones. Epiphyseal cartilage plates were thin and there was derangement of growth zones. Areas of primary and secondary spongiosa were deficient in trabeculae, osteoblasts and osteoclasts. Analysis of femora, humeri and lumbar vertebrae from ADR-treated rabbits revealed increased water and fat content and significant decreases in bone density compared to age-matched controls. Cortices of long bones were roentgenographically thin and contained large irregular spaces evident microscopically. Evaluation of bone ash from ADR treated rabbits revealed significant increases in the percentage of calcium and phosphorus, although Ca/P ratios were not different from controls. Results of in vitro studies indicate that ADR binds readily to nondemineralized, but not demineralized, fresh cortical bone powder. The findings of decreased bone density, histopathologic alterations, and a paucity of osteogenic cells in ADR treated rabbits are interpreted as retardation of bone maturation. It is suggested that ADR affects adversely both the organic and inorganic fractions of bone. Due to its unique characteristics of cytostatic action, binding to metal cations and orange-red fluorescence, ADR is a novel chemical agent that may be useful in experimental bone studies.


HPO2-4 content in enamel and artificial carious lesions. The HPO2-4 and CO2-3 content was determined in sound enamel and in material collected from artificially produced carious lesions.  The method described shows that the HPO2-4 content can be determined from the 875 cm(-1) infrared absorption band if correction for the CO2-3 contribution are made.  The I.R. spectra show that the HPO2-4 content in sound human or bovine enamel is about 5% by weight.  In artificially produced carious lesions (pH=4.0), the HPO2-4 content is in the order of 15 wt%.  Most likely, the HPO2-4 ions in sound and carious enamel have a different enviroment.


Electrical modification of disuse osteoporosis. Localized electrical stimulation of the immobilized hind limb of young rabbits resulted in dramatically more bone in the tuber calcis (heel bone) compared to the severe loss of bone (osteoporosis) seen in unstimulated, immobilized controls. Detailed histological evaluation using microradiography and fluorescence and polarization microscopy showed that the increase was probably due to an overall inhibition of surface cortical bone loss )endosteal resorption) and an increase in the quantity of the new immature bone. There was also evidence of increased osteonal resorption in the stimulated animals.


Effect of 1,25-dihydroxycholecalciferol on ethanol mediated suppression of calcium absorption. Rats raised on laboratory diet and given 20% ethanol in water as a sole source of fluid for 12 days were given 0.2 mug of 1,25-dihydroxycholecalciferol 24 h before measuring duodenal calcium transport by an in vitro everted gut sac technique. This vitamin D metabolite did not reverse the ethanol-induced inhibitiom of transport capacity. Ultrastructural studies of intestinal epithelial cells from animals ingesting ethanol demonstrated changes in mitochondria and other subcellular organelles as well as accumulation of electron-dense, calcium-containing granules in microvilli and a paucity of granules in mitochondria. The results suggest that the inhibition is mediated at the intestinal level, affecting mechanisms which are probably independent of Vitamin D, and in part by an interference in transport of calcium from microvilli to other intracellular sites.


A quantitative method for the application of compressive forces to bone in tissue culture. A quantitative method for the application of compressive forces to long bones in culture is described. Using this method it was found that a physiological pressure of 80g/cm sq. applied to tibiae of 16-day-old chick embryos reduced glucose consumption to 50% of controls. Twenty four hours after the release of pressure glucose utilization again increased, approaching control levels. A pressure of 80 g/cm sq. also stimulated thymidine incorporation into DNA. The same pressure decreased the size of the extracellular fluid pool by 8%, but had no effect on the rate of equilibration of this pool with 22Na.


The effect of the active principle of Solanum malacoxylon on rabbits and the inhibition of its action by actinomycin D. The oral administration of an aqueous extract of 2.5 g of the dried leaves of Solanum malacoxylon (DLSM) produced a rapid hyperphosphataemia, which becomes apparent 4 to 8 h after treatment, in the rabbit. This effect was not accompanied by any significant change in plasma calcium, mangesium, total protein, albumin, urea and creatinine concentration. The urinary excretion of calcium, magnesium, and inorganic phosphate was markedly increased 24 and 48 h after treatment with the extract and was not accompanied by any significant change in the urinary excretion of hydroxyproline. The hyperphosphataemic effect of the DLSM extract was inhibited by Actinomycin D. It appeared that DLSM does not cause bone resorption in normal rabbits maintained on a diet containing adequate levels of calcium and phosphorus. The increased urinary excretion of calcium magnesium and inorganic phosphate after treatment with DLSM extract appeared to be due to increased intestinal absorption. The absence of any significant change in plasma urea and creatinine concentration after treatment with DLSM extract, and the inhibition of the hyperphosphataemic effect by Actinomycin D, indicated that this was a characteristic response of the rabbit to the active principle, and that it was not due to renal damage. The inhibition of the hyperphosphataemic effect of DLSM by Actinomyein D showed that its action involves the transcription of DNA to RNA and protein synthesis.


Colour television image analysis of carious lesions. The new technique of colour television image analysis has been used to produce seven-colour contour maps of the radiodensity of micro-radiographs of enamel caries. This method permits the detailed measurement of the mineral content of enamel carious lesions to a sensitivity of +/-3% of the level of complete mineralisation. By selection of appropriate aluminium step-wedges, exposed simultaneously with the tooth section, the whole range of mineral content can be assessed.


Amorphous calcium precipitations in human aortic valve. Spheroidal, granular, and fibrillar particles were observed in human aortic valve calcifications. Spheroids were similar to amorphous calcium phosphate shown previously in syn thetic preparations and in bone. The frequent coexistence of needle shaped hydroxyapatite crystals with granular and fibrillar particles suggests that the latter are also amorphous calcium phosphate and may be precursors of hydroxyapatite. All three types of particles had a tendency to form laminated and spherular secondary and failed to give a crystalline pattern by electron diffraction.


Effect of carbonate and biological macromolecules on formation and properties of hydroxyapatite. Amorphous calcium phosphate (ACP) was transformed at 25 degrees to hydroxyapatite (HA) in horse and bovine serum; solutions of serum-protein fractions in tris-HC1 buffer (pH 7.4), and pH 7.4 buffers containing from 0.1 to 10 times physiological CO3(2-) concentration. The ACP-to-HA transformation was slower in whole serum and serum fractions than in control buffer solution. The observed adsorption of serum proteins on ACP and HA probably inhibits both the dissolution of the ACP particles and the growth of HA crystals. After 72 h all transformations were complete as determined by X-ray diffraction. The HA crystal dimensions decreased with increasing C03(2-) but the shape, as shown by X-ray linewidths, was relatively constant up to about 4% CO3(2-). At 15% CO3(2-) the crystals were more equiaxial and less needle-like in habit. The radial distribution function (RDF) of HA with 3.7% CO3(2-) is less well resolved than the RDF of HA with ambient CO3(2-) (1.1%). The peaks are less sharp and their amplitude falls more rapidly with increasing atomic separation than for low CO3(2-)-HA. These effects show that CO3(2-) decreases the regularity of the atomic arrangement when incorporated in HA. The rapid decrease, with increasing CO3(2-) content, of the IR splitting of the P-O bending mode of CO3(2-)-HA is attributed to reduced crystal size and possibly to a perturbation of the crystal field due to CO3(2-)-induced lattice distortion. Finally, for bone mineral, it is probable that the poor resolution of the X-ray and IR patterns is due, in large part, to small crystal size and internal disorder caused by CO3(2-).


Effect of long-term administration of fluoride on physico-chemical properties of the rat incisor enamel. Rats were maintained on drinking water containing different amounts of fluoride (0, 9, 23 45, 68, and 113 ppm) for 70 days. Physico-chemical properties of the incisor enamel were examined after fluoride administration, using contact microradiography, histochemistry, and microhardness tests. The tooth enamel formed during high fluoride exposure showed marked hypocalcification. Much of organic substance in the enamel seemed to have been retained. In addition, the microhardness of enamel showed a marked decrease. These changes were most prominent in the outer region of enamel and were proportional to the concentration of fluoride administered. Such changes following fluoride administration indicated inhibition of enamel maturation, i.e., an inhibition of the progressive depposition of minerals and/or in inhibition of organic matrix withdrawal by ameloblasts. Enamel seemed more affected by fluoride than dentine.


Recurrent hyphema after surgery.

Recurrent hyphema after surgery. At variable times after anterior segment surgery spontaneous bleeding may occur into the anterior chamber from a gap in the scleral wound. The patient complains of blurred vision in the morning and examination reveals blood in the anterior chamber. Gonioscopy reveals a bleeding point in the scleral would. In the majority of patients the condition is benign and does not require special treatment.


Hemangiomas of the optic disc.

Hemangiomas of the optic disc. Seven cases of hemangioma of the optic disc are presented. A survey of the literature is summarized and the differential diagnosis and appropriate management discussed.


Hereditary macular dystrophy. A clinical and genetic study of two specific forms. Four families with nine members affected with autosomal recessive macular dystrophy (Stargardt's Disease) and one family with six members affected with autosomal dominant macular dystrophy have been examined. Age of onset, rate of visual deterioration, fundus appearance, electroretinography and dark adaptometry have been compared in the various families. Some differences, particularly in the rate of visual deterioration and in the fundus appearance were noted between the recessive and dominant forms. Despite these differences in the clinical and related features, the genetic implications are of greater importance to the affected individuals. Genetic counselling which provides recurrence risks of the disorder in the affected individuals' siblings and children should be included in the assessment of patients with these forms of hereditary ocular disease.


Evaluation of the Friedmann Visual Field Analyser. Visual fields were assessed in 320 eyes of 169 patients, using the Friedmann Visual Field Analyzer (F.V.F.A.) and the Oculus perimeter. The F.V.F.A. was found to be a rapid indicator of both the presence, the location and the density of scotomata. Because some defects were missed by the F.V.F.A. it should be used in combination with some other technique to search for early defects, particularly in the Bjerrum region. Since the F.V.F.A. can be used easily by a technician, the physician's efforts can be utilized to best advantage in exploring those regions likely to contain abnormalities.


Impact resistance of ophthalmic lenses of various strengths and the influence of frame design. Protection of the eyes by safety type spectacle, sunglass and goggle lenses has received considerable attention in recent years. Such protection can be enhanced by design of the frame. We report from 476 lenses mounted in 238 frames and subjected to 9,397 impacts. Maximum blows were delivered by a one inch diameter steel ball falling from a height of 122 inches. Results indicated that the force required to fracture lenses in plastic frame mountings was more than twice that required for fracture of identical strength lenses in wire rims. Minus cylindrical lenses were the most frangible. The lowest fracture and posterior dislocation rates were found in industrial plastic frames with a retaining lip. Greater energy attenuation can be induced in a heat tempered glass lens by even edge compression. Good lens and frame design, when properly correlated, should provide impact  attenuation distinctly exceeding conventional standards.


A long-term evaluation of silicone retinopathy in monkeys. Six owl monkeys were exposed intravitreally for 6 to 28 months to Dow Corning Medical Fluid 350 in a morphologic study of silicone retinopathy. Fellow eyes of each silicone-injected animal and six eyes from three normal untreated monkeys served as controls. In addition, two eyes were treated post-mortem with silicone oil to insure that no artefact redistribution occurred. Each case was studied histochemically in frozen sections, with electron microscopy of Epon-embedded materials. All silicone-injected eyes showed numerous empty spaces in the inner segment of the retina adjacent to the vitreoretinal interface, corresponding to the intercellular spaces between Müller's filbers. These spaces contained numerous spherical bodies encircled by a homogeneous electron-opaque material, suggesting a silicone-phospholipid complex. Marked degeneration of small ganglion cells was seen. Müller's fibers appeared to be shrivelled. The lack of phospholipids in the inner segment of the visual receptors was marked, although no significant morphologic lesions were detectable. Abnormally high ATPase activity was found in both plexiform layers. There were no such lesions in the untreated control eyes, nor any detectable artefactual redistribution of silicone oil in the eyes treated post-mortem with Medical Fluid 350.


Mechanical Excision and removal of intravitreal vessels. I. In animals. We wished to know if excision of artificially produced intravitreal vessels would cause bleeding and if the hemorrhage could be controlled by increasing the intraocular pressure. In 17 rabbit eyes, the distal end of several intravitreal blood vessels was excised and removed by the Peyman vitrophage. No significant bleeding occurred from the vessels in 13 eyes, and in the remaining four bleeding stopped after 30 seconds or less of increased intraocular pressure. In one month of observation after surgery, there was no evidence of delayed hemorrhage. Electron microscopy of several transected intravitreal vessels revealed that vessel constriction, platelets and fibrin strands contributed to the prevention of immediate and delayed hemorrhage.


The vitrophage in ocular reconstruction following trauma. We propose a technique using the Peyman vitrophage, a vitrectomy instrument, for the surgical repair of acute and chronic injuries to the anterior segment, such as perforating corneal injuries and complications of cataract extractions. A pars plana approach allows insertion of the vitrophage into the eye with minimal surgical manipulation. All lens, iris, and vitreous remnants are completely removed. We have achieved excellent results in cases of severe eye injuries.


Delayed cataract formation after alkali burn. A small posterior subcapsular cataract developed almost a year after a moderately severe alkali burn of the eye. The cornea recovered completely. Cataract and glaucoma following alkali burns are discussed. The development of delayed cataract should be kept in mind in compensation cases before a final disability report is made. Topical steroids may potentiate the detrimental effect of alkali on the eye.


Expulsive choroidal hemorrhage.

Expulsive choroidal hemorrhage. An unusual case of expulsive choroidal hemorrhage is described. The hemorrhage developed sixteen days after an uneventful cataract extraction and after the removal of corneoscleral sutures. The different types of expulsive hemorrhage, their pathogenesis and management are discussed. Eye surgeons are urged to handle this condition with determination and optimism.


Some pathologies of sensory and neural hearing loss. Recently surgical implantation of devices to stimulate the auditory nerve in man makes it apparent that sensory and neural pathologies of deafness need to be differentiated from each other. In this paper 10 exemplary cases are presented. In addition, an attempt is made to compile the information now available about sensory and neural pathologies in the various diseases that cause deafness. Superficially, it would appear that most such entities are sensory in nature and thus theoretically might be amenable to auditory nerve stimulation. However, loss of supporting cells seems to be associated with cochlear nerve fibre degeneration. Many individuals may, therefore, eventually develop combined pathology. The paucity of knowledge of pathology of the auditory pathways and their radiations in deaf persons is recognized as a limiting factor in attempts to predict which patients might benefit from auditory nerve stimulation. It is not within the scope of this paper to delineate the possible deleterious effects that cochlear implants might have on the auditory nerve.


Mechanical properties of human mitral valve chordae tendineae: variation with size and strain rate. A knowledge of the mechanical properties of valve tissue is a necessary prerequisite for a better understanding of valvular behavior and design of prosthetic heart valves. Elastic response of chordae tendineae under strain rates of 0.05 cm min(-1)(6.25% min(-1)) to 12.7 cm min(-1)(1600% min(-1)) were obtained by the application of an uniaxial tensile stress using an Instron machine. The chordae exhibited viscoelastic properties in that extensibility decreased with increasing strain rates. The approximate maximum physiological strain rate of the chordae was estimated from echocardiographic traces at the instant of valve closure, and a high value of 29 (S.D. equals 9) cm s(-1) (2000% s(-1)) was found. The breaking strain and stress were found to have values of 21.4 plus or minus 0.5% and 3.1 plus or minus 0.1 times 10(8) dyn cm(-2) respectively, and were independent of strain rates (1 dyn equals 10(-5) N). These values are typical of collagen fibers. The final modulus, before the proportional limit, was found to be about 10(9) dyn cm(-2), which is again typical of collagen fibers. In addition, smaller chordae exhibited less extensibility than the larger chordae. This behavior could be due to structural and functional differences and allows the more centrally inserted chordae to maintain an even valve surface during valve closure.


Effects of carotid baroreceptor stimulation and renal denervation on the medullary concentration gradient in rat kidneys. Unilateral stimulation of carotid baroreceptors in unanesthetized rats treated with desoxycorticosterone acetate caused highly significant decreases in solute content and osmolar concentration in the inner renal medulla. There was also a corresponding decrease in urine osmolality and a large increase in the excretion of sodium. In rats subjected to water diuresis, the changes in medullary tissue composition were similar but sodium excretion was very low, indicating that the natriuretic response was not a result of medullary "washout" per se. Renal denervation had no significant effect on medullary tissue composition and did not prevent the dissipation of the cortico-medullary concentration gradient following carotid baroreceptor stimulation. It is concluded that the changes in inner medullary composition are mediated by a humoral agent.


The effects of acute carbon monoxide intoxication on the cerebral energy metabolism of the rat. The cerebal metabolic effects of 60 min exposure to 0.5, 1.0, 1.5, and 2.0% carbon monoxide (CO) and 60 min exposure to 1.0% CO were studied in lightly anesthetized rats by measurement of brain tissue contents of glycolytic and citric acid cycle intermediates, as well as tissue energy phosphates. The results indicate that cerebral energy homeostasis is maintained until advanced levels of CO intoxication (2.0%) are reached. Animals exposed to 2.0% CO developed significant decreases in systemic blood pressure, with attendent decreases in cerebral ATP, increases in ADP and AMP, plus early depletions of tissue citrate and alpha-oxyglutarate. The similarity of this pattern to that previously documented for various cerebral oligemic states suggests a possible modifying role for altered cerebral production in its production. A correlation between conscious behavior and cerebral energy state was suggested by the observation that unanesthetized animals exposed to 1.0% CO for 30 and 60 min retained consciousness, whereas animals  exposed to 2.0% CO for 30 min became unresponsive late on in the exposure. A comparison of CO induced changes in intermediary metabolites, energy phosphates, intracellular pH, and cytoplasmic redox state with those seen in hypoxemia indicate no basic qualitative or quantiative differences in the metabolic response of brain tissue to the two conditions.


Biochemical criteria for the evaluation of drug efficiency on adjuvant arthritis and nephrotoxic serum nephritis in the rat: studies with phenylbutazone, L-Asparaginase, colchicine, lysine acetylsalicylate, and pyridinol carbamate. The levels of serum orosomucoid, haptoglobin, and seromucoid were evaluated as possible quantitative criteria for the estimation of drug efficiency in adjuvant arthritis and nephrotoxic serum nephritis. In adjuvant arthritis, haptoglobin, seromucoid, and chiefly orosomucoid serum levels were generally very sensitive to anti-inflammatory agents such as phenylbutazone and pyridinol carbamate, and to immunosuppressive agents such as L-asparaginase. There was a significant correlation between the serum levels of these glycoproteins and the arthritis scores. In nephrotoxic serum nephritis, seromucoid levels were correlated with the proteinuria of the autologous phase and were found to be a good complementary criterion for the analysis of the efficiency of pyridinol carbamate, colchicine, iysine acetylsalicylate, and L-asparaginase.


Isoosmotic transport of fluid across the hamster small intestine in the presence of phlorizin-induced inhibition of sugar transport. Experiments were performed to investigate whether the fluid transported across the small intestine is isoosmotic with the mucosal solution when the active transport of glucose is partially inhibited. Everted hamster mid small intestine was incubated in one of the following four mucosal solutions: (1) Isotonic control, Krebs-Ringer bicarbonate solution containing 10 mM glucose (KRBSG), (2) Isotonic with phlorizin, KRBSG + 5X10-5 M phlorizin, (3) Hypertonic control, KRBSG + 50 mM mannitol, (4) Hypertonic with phlorizin, KRBSG + 50 MM mannitol + 5x10-5 M phlorizin. The serosal surface of the intestine was not bathed. Results indicate that the transported fluid was always isoosmotic with any of the mucosal solutions used. When the mucosal solution was made hypertonic with mannitol, the concentration of glucose and electrolytes in the absorbate increased, and as a result, the absorbate became hypertonic and isoosmotic with the mucosal solution. The presence of phlorizin either in the isotonic or in the hypertonic mucosal solution decreased the glucose concentration of the absorbate, but the transported fluid became isoosmotic with the mucosal solution due to a higher concentration of Na, K, and their associated anions. Phlorizin caused a decrease in the transmural potential difference. In spite of this, the presence of this glucoside in the mucosal solution increased the transport of sodium in relation to glucose transport. It is suggested that, at the concentrations used, phlorizin inhibits sodium movement through the electrogenic pathway, but increases the transport of this ion through the non-electrogenic route. This increase in neutral sodium transport seems to compensate for the low concentration of glucose in the absorbate, so that the absorbate becomes isoosmotic with the mucosal solution whether the latter is isotonic or hypertonic. It is suggested further that isoosmotic transport of fluid is an inherent property of the small intestine and that there may be an osmoregulatory mechanism in the gut which controls this process.


Role of the C-terminal group for the biological activities of angiotensin. The C-terminal group of angiotensin II (ATii)  , 1-Sar-ATii, and 1-beta-Asp-ATii was esterified to reduce degradation of the peptides and carboxypeptidases. Biological activity of esterified angiotensins was measured in vivo (rat blood pressure) and in vitro (rabbit aorta strip). Degradation in vitro by purified carboxypeptidase was estimated from the intensity of the phenylalanine spot on paper chromatography. Disposition of esterified angiotensins by rabbit aorta strips was studied with the oil immersion technique of Kalsner and Nickerson, Can. J. Physiol. Pharmacol. 46, 719-7308 (1968a). The results indicate that esterification of C-terminal group of ATii: (a) reduces the potency in vivo and to greater extent the affinity in vitro, (b) delays the onset of the contraction in vitro, (c) does not affect the intrinsic activity, (d) prolongs the time of relaxation of rabbit aorta strips in oil, (e) prevents the degradation by purified carboxypeptidase. It is proposed that C-terminal group of ATii contributes to affinity but not to instrinsic activity and facilitates the diffusion of the peptide to receptor sites. Esterification of this group prevents the degradation of the peptide by carboxypeptidases; accordingly, the duration of action in vivo is prolonged and the rate of relaxation of aortic strips in oil is reduced. When esterification of the C-terminal is combined with the replacement of Asp by beta-Asp in position 1, no relaxation of aortic strips occurs after oil immersion. This suggests that carboxypeptidases, and to a minor extent aminopeptidases, are responsible for the inactivation of angiotensin by rabbit aorta.


The metabolism of 4-chlorobiphenyl in the pig. 1-Chlorobiphenyl was administered retrocarotidly in a saline oil emulsion to anesthetized pigs. The urine obtained from the pigs 2 h after injection of the 4-chlorobiphenyl was analyzed for metabolites. Mass spectrometric analysis indicated the presence of a monohydroxylated species (M+ 204) and a dihydroxylated compound (M+ 220) and these were identified as 4'-chloro-4-biphenylol and 4'-chloro-3,4-biphenyldiol, respectively. Examination of the urine extracts from pigs 0.5, 1, and 2 h after administration of the 4-chlorobiphenyl indicated an increase in both urinary metabolites with time, however, neither compound was detected in the bile. Blood and organ samples were examined also for metabolites and the results clearly showed the presence of 4'-chloro-4-biphenylol in the blood, kidney, and liver and absence in the lung, brain, and heart. The diol was not observed in any of these samples.


Action of acetazolamide on the chick embryo during late development. Acetazolamide was injected into chick embryos on the 14th or 15th day of incubation. Doses ranging between 5 and 10 mg per egg produced a retardation in the growth of long bones. The affected bones contained a normal proportion of mineral as determined by ashing and presented a normal histological picture. On the basis of these findings, it is suggested that the alterations were not due to a specific direct effect of the drug on bones. The incorporation of 131-I by the thyroid glands of acetazolamide-injected embryos was analyzed radioautographically and quantitated on the same 6 mu-paraffin sections, with a thin window Geiger counter. The incorporation appeared notably reduced 3 h after the injection of acetazolamide and the reduction persisted for a least 24 h.the electron microscopical observation of thyroid follicular cells from similarly treated embryos showed that the cytological characteristics indicating an active protein synthesis were unmodified with respect to those found in control embryos. These results may indicate that acetazolamide inhibits the iodination of the throid hormone without interfering with the synthesis of the globulin. It is suggested that the growth retardation observed in the embryos treated with acetazolamide may be secondary to the action of the drug on the thyroid gland, although this action appears to be a transitory one.


Effect of pyrazole on ethanol metabolism in ethanol-tolerant rats. Adult male rats were pair-fed liquid diets, providing 37% of calories as ethanol or sucrose, for 1 month. Alcohol dehydrogenase (ADH) activity in the cytosol fractions of liver homogenates from the two groups did not differ with respect to total activity per 100 g body weight, Km for ethanol, or Ki for pyrazole. Other rats, fed in the same way, were fasted for 18-24 H, then given an intraperitoneal injection of pyrazole followed 1 h later by an injection of ethanol, 3g/kg. Blood alcohol curves showed an unexplained slower rise to maximum level in the chronic alcohol group. Both groups showed a period of several hours in which the blood alcohol stayed at the respective maximum concentrations, which were higher in the control group. After 7-8h the alcohol concentration began to fall in both groups, significantly more rapidly in the chronic alcohol-fed animals. A kinetic analysis shows that the results are adequately explained by the known effects of pyrazole on the ADH-mitochondrial system. The results are interpreted as evidence against the function of any microsomal ethanol oxidizing system in vivo.


Substance P and spinal neurones.

Substance P and spinal neurones. When applied by microiontophoresis, substance P (sP) had a strong, but slow and prolonged excitatory action on nearly half the neurones tested in the lumbar spinal cord of cats. Motoneuronal antidromic field potentials only occasionally showed a significant effect of sP. Cerebral cortical neurones in cats and rats were much less readily excited than spinal interneurones. Some unresponsive units showed evidence of a depressant effect of sP. Although sP may have a significant function in central afferent pathways, it is not likely to be a quickly-acting synaptic transmitter.


Correlation of structural changes at different levels of the jejunal villus with positive net water transport in vivo and in vitro. Experiments were done for indentification and localization of certain structural changes at different levels of jejunal villus of the hamster during positive and negative water transport across the intestine in vivo and in vitro. Positive transport occurred when the mucosal surface of the intestine was bathed (in vitro experiments) or perfused (in vivo experiments) with isotonic Krebs-Ringer bicarbonate solution containing 10 mM glucose, and negative water transport was achieved by rendering this solution hypertonic with 150 mM mannitol. Results indicate that during positive net water transport the intestine in vivo transported more fluid and exhibited a more conspicuous dilatation of the lateral intercellular spaces (L.I.S.) than did the in vitro preparation. Dilatation of the L.I.S. in both preparations was present only in the apical part of the villus, suggesting that this is the principal site of water absorption. When the mucosal solution was made hypertonic with mannitol, the L.I.S. in the in vivo intestine totally collapsed, whereas in the in vitro intestine these spaces remained open very slightly. These morphological changes correspond well with our finding that in the presence of the hypertonic mucosal solution there was a greater net negative water transport in vivo than in vitro. Incubation of the intestine in the isotonic mucosal solution produced subnuclear swelling of the mid-villus epithelial cells, and this morphological change was associated with an increase in the water content of the tissue. Perfusion of the in vivo intestine with the isotonic solution produced neither the swellings nor the increase in water content of the tissue. In the presence of hypertonic mucosal solution there was a water loss from the tissue both in vivo and in vitro, and these swellings were not observed. These results are discussed in relation to intestinal sugar transport and to the maturity of the epithelial cells, and it is concluded that transport studies on in vitro preparations may provide valid information on a qualitative basis, if not on a strictly quantitative basis.


The effect of hemicholinium-3 on choline and acetylcholine levels in a sympathetic ganglion. Pregangliaaonic stimulation of the cat's superior cervical ganglion in the presence of hemicholinium-3 (HC-3) produced the expected depletion of acetylcholine (ACh) stores, but failed to cause a corresponding reduction in the choline content. These results suggest that either HC-3 possesses an intracellular site of action or that in lower doses it selectively inhibits a specialized choline transport system in cholinergic nerves. At a dose of 2 mg/kg, HC-3 probably blocked ACh synthesis completely in ganglia stimulated at 20 Hz. Under these conditions, there was a rapid depletion of ACh to about 50% of control levels during the first 5 min of stimulation and thereafter the rate of decline in ACh levels proceeded at a much slower pace. Since the 2 mg/kg dose of HC-3 did not raise plasma choline concentrations, it may be assumed that non-specialized choline transport systems in other tissues were not significantly inhibited by this dose of HC-3. However, when the dose of HC-3 was increased to 4 mg/kg, plasma choline levels increased by 58%.


Pentobarbital inhibits the billiary excretion of organic acids: a study with succinysulfathiazole in the rat. The present study was undertaken to determine whether the use of pentobarbital as an anesthetic reduces the biliary excretion of acidic drugs in rats. The drug chosen for the experiment was succinylsulfathiazole, a compound excreted unmetabolized in the bile. Animals anesthetized with urethane excreted 22.1% of the dose in the bile as compared to only 8.4% for the same time period in pentobarbital anesthetized animals. The choice of anesthetic did not affec the bile flow but did influence the bile/liver concentration gradient of succinylsulfathiazole, with the pentobarbital treated rats demonstrating a significantly lower value. Despite the higher biliary excretion of succinylsulfathiazole in the urethane treated rats, the total amount in the bile plus urine was 60% of the dose in the urethane anesthetized animals as compared with 62% in the pentobarbital treated rats. These results suggest that pentobarbital reduced the hepatic transport of succiylsulfathiazole into the bile. The question whether urethane is a preferred anesthetic for biliary excretion studies warrants further investigation.


Differential uptake and metabolism of sitosterol and cholesterol by Achlya, Pythium, and Phytophthora species. The relative ability of isolates of Achlya bisexualis and A. ambisexualis and isolates of Pythium and Phytophthora to take up and metabolize sitosterol and cholesterol was studied. Species of Pythium and Phytophthora took up cholesterol and sitosterol efficiently, whereas Achlya species took up booth sterols inefficiently. Species of Pythium and Phytophthora produced a polar metabolite and esters from sitosterol as they did from cholesterol. Achlya species did not produce the polar metabolite from either sterol. In these experiments Achlya species produced esters only from cholesterol; however, their failure to produce esters from sitosterol may have been due to the higher sitosterol than cholesterol concentration.


The effect of sodium chloride on the growth and morphology of dermatophytes and some other keratolytic fungi. A study of the influence of various concentrations of NaC1 on 21 species of dermatophytes and other keratolytic fungi was made. Based on the sensitivity of the species to various concentrations of NaC1, it was possible to divide them into five groups. Microsporum ferrugineum and Trichophyton concentricum and T. tonsurans were the most sensitive to NaC1 and were inhibited by 5%. The greatest number of species were inhibited by 12% NaC1. The fungi most tolerant to NaC1 were M. cookei and M. nanum, and T. mentagrophytes, T. schoenleinii, and T. terrestre. These species were inhibited by 15%. NaC1 prevented any variant change in Epidermophyton floccosum, T. mentagrophytes, and M. gypseum, but promoted a change in phenotype in M. audouinii and M. cookei, and T. gallinae. It is suggested that the word "pleomorphism" be replaced by the term sterile albinism. This term refers to that kind of cultural change when there is no evidence of sporulation and the white fluffy mycelium consists of fine sterile hyphae. Sterile albino strains of E. floccosum were induced to form a macroconidia on Sabouraud cycloheximide chloramphenicol gentamicin agar (SCCGA) containing 3-5% NaC1. Also, M. audouinii formed microconidia and macroconidia in velvety growth cultured on SCCGA containing NaC1.


Some physiological effects of near-maximum growth temperatures on an obligately psychrophilic marine bacterium. The heat inactivation of the obligately psychrophilic marine bacterium Ant-300 was investigated in terms of glucose uptake, the oxidation of glucose to CO2, and permeability control. At 13C, the maximum temperature for growth, and at slightly higher temperatures, CO2 evolution decreased with time during the oxidation of exogenously supplied glucose. The decrease in CO2 evolution appeared to be a result of heat-induced restrictions on glucose uptake. Leakage of intracellular metabolites apparently contributed to the cells decreased ability to take up glucose at elevated temperatures. A consequence of these heat-induced changes seemed to be the acceleration of cell starvation.


Aeromonas proteolytica--a halophilic aeromonad? Aeromonas proteolytica, a halophilic bacterium originally isolated from the intestine of a marine isopod, was compared with 93 strains of Aeromonas hydrophila and representative strains of five similar genera in a computer and serological analysis. Aeromonas proteolytica was peritrichate and non-reactive with six A. hydrohila antisera, and possessed a percentage guanine + cytosine ratio (49.5) outside the range for other aeromonads (55-62%). Moreover, in the computer analysis it shared a lower level of similarity with other aeromonads than with both strains of Vibrio anguillarum tested.


Streptomycin resistance in chloramphenicol-producing strains of Streptomyces species 3022a. Resistance to low (5 mug/ml) concentrations of streptomycin in agar media was not inherited by all of the surviving population. Outgrowth of cultures in liquid media supplemented with the antibiotic depended upon inoculum size. Antibiotic titers in the supplemented cultures decreased during incubation, and an inactive radioactive product was detected when [14C] streptomycin was used. This low-level resistance is, therefore, attributed to enzymic inactivation of the antibiotic. Growth 10 mug/ml or higher concentrations of streptomycin on agar media was due to selection of resistant variants present in the parent strain. A range of such variants existed, decreasing in frequency as their degree of resistance increased. Examination of one that was resistant to moderate concentrations of streptomycin, (25 mug/ml) and a second that was resistant to high (100 mug/ml) concentrations of streptomycin suggested that both possed ribosomes which had lower affinity for the antibiotic than those of the parent strain, and that tolerance to high levels of streptomycin was due to a resistant ribosomal system for protein biosynthesis.


Cell size as an indicator of changes in intracellular composition of Azotobacter vinelandii. Cell size, measured electronically, was correlated to changes in cellular composition, number, and morphology of Azotobacter vinelandii OP during batch growth. The effect of a changing abiotic environment on these features of the cell is discussed. For this organism exponential growth was unbalanced growth and cell-size change was a sensitive indicator of this growth pattern. Cell-size measurements have the potential to give a rapid assessment of intracellular compositional changes.


The bacterial degradation of fluoranthene and benzo[alpyrene. A gas chromatographic method to determine fluoranthene and benzo[a]pyrene at concentrations close to the limit of their solubility in water was used to identify several species of pseudomonads able to degrade fluoranthene and benzol[a]pyrene.  Degradation occurs most rapidly in cultures in the stationary phase, is heat sensitive, requires oxygen, and is enhanced in the presence of cyanide.


The influence of season and stage of development of plant on Endogone mycorrhiza of field-grown wheat. A quantitative and qualitative survey of the indigenous Endogone population in wheat field soil and vesicular-arbuscular mycorrhiza in wheat roots as influenced by season and by the stage of development of the wheat plant was made.  The number of Endogone spores in wheat field soil remained relatively unchanged in winter until January during the period of maximum root growth.  The extent of formation of arbuscules was influenced by the stage of development of the wheat plants.


Enhancement of adhesion of the marine Chlorella vulgaris to glass. The adhesion of washed cells of a marine Chlorella vulgaris to solid surfaces was enhanced by non-diffusible material recovered from Chlorella exudate, marine bacterial cultures, natural seawater, and fouled marine surfaces.  Materials isolated from certain bacterial cultures and from particulate materials filtered from seawater were three orders of magnitude more active than Chlorella exudate per unit weight.  Active polymer materials from several sources were chromatographed on DEAE cellulose.  The major fraction eluted with dilute base contained both protein and carbohydrate and enhanced adhesion more than the unchromatographed material.


The recovery of nocardial recombinants from broth cultures. Broth culture media were examined for their ability to support growth and recombination between compatible strains of Nocardia erythropolis. Nutrient(Nut) and peptone-yeast-extract (PY) broths supported the production of recombinants after 36 h of incubation with a maximum recovery of about 6.0 times 10(-7) CFU/ml. Cells mated in trypticase broth (TB) yielded the highest incidence of recombinants (1.0 times 10(-2) CFU/ml) in the absence of parental cell growth. From a chemically defined mating broth (CD), supplemented with limited amounts of the parental-growth requirements, recombinant recovery reached about 1.0 times 10(-4) after 120 h of incubation. The recombinant class types obtained from Nut- or PT-mated strains were predominantly auxotrophic while TB-mated strains produced stable proteotrophs. The high incidence of recombinant types from TB-mated strains was due to growth of selected prototrophic classes. Studies with strains mated in PY broth indicated that the mating event occurs at very low frequencies between older, stationary-phase cells rather than between actively growing, log-phase cells.