Head injuries in children: a prospective five year follow-up. A five year follow-up study was conducted with two groups of head-injuried children. 131 younger than 9 years old at time of injury and 100 older than 9 years. The four aspects studied were neuropsychological function, neurological status, EEG status, and school progress. There was an extended recovery process over time, as well as evidence of a differential rate of recovery for the four aspects measured.


Intraspinal bleeding in haemophilia: successful treatment with factor VIII concentrate. A severely affected haemophilic boy became tetraparetic as a result of a spontaneously occurring intraspinal haematoma. Myelography defined the extent of the lesion and showed it to be extradural in site. Infusion of large doses of factor VIII concentrate led to dramatic improvement and avoided the need to operate.


Clinical consequences of corticectomies involving the supplementary motor area in man. Three patients with well-mapped, circumscribed ablations of the medial part of the frontal lobe are reported. A specific clinical evolution in 3 stages was observed: (1) post-operatively there was global akinesia, more prominent contralaterally, with an arrest of speech; (2) recovery occurred suddenly but even then there was severe reduction of spontaneous motor activity contralaterally, an emotional type facial palsy and a reduction of spontaneous speech; (3) long after the operation the only sequela was disturbance of the alternating movements of the hands. The anatomical basis of these disorders appears to be a lesion of the supplementary motor area (SMA). Three main points have been discussed, namely: (1) the nature of the motor disorder which may be a disturbance of the function of the SMA in initiating and sustaining spontaneous and automatic motor activity; (2) the nature of the arrest of speech which appears not to be aphasic; the studies reported in the present paper do not support a left cerebral dominance for the SMA as suggested by previous studies; (3) the method of clinical examination appears to be important in distinguishing between spontaneous and voluntary motor and speech performance. Differences in method may account for differences between our findings and those reported in previous studies.


Vacuolar myopathy associated with chloroquine, lupus erythematosus and thymoma. Report of a case with unusual mitochondrial changes and lipid accumulation in muscle. Pathological and biochemical observations are presented in a 55-year-old woman with lupus erythematosus and thymoma who developed a vacuolar myopathy while being treated with chloroquine. Electromyography showed prominent spontaneous muscle activity including myotonic discharges. Vacuoles were present in all fibre types but, in contrast to previous cases of chloroquine myopathy, were most prominent in intermediate fibres. Electron microscopy showed cytoplasmic sequestration by membranes in proximity to the t-system, many autophagic vacuoles, tubular networks, and a variety of membranous bodies, some identical to those found in certain forms of cerebral lipidosis. Other features not previously described in chloroquine myopathy included prominent mitochondrial vacuolation and sequestration of glycogen within mitochondria. Thin-layer chromatography of muscle homogenates showed an increase in all major neutral and phospholipid fractions.


[Hemispheric asymmetries of the human brain]. The authors studied 181 brains, 103 of which were dissected. They observed a "T1-T2 bridge" over the first temporal and second temporal gyri more often on the left side than on the right. This asymmetry was more frequent in males than in females. The maximal width of the superior aspect of the second temporal gyrus was greater on the right side in the majority of cases. By contrast, the fusiform gyrus was found wider on the left side in most subjects. The length of the precuneus was greater on the right. The greater size of the left planum temporale could be correlated with the sectional area of the anterior white commissure. The same correlation was found between the length of the precuneus and the area of the latter commissure. Anatomical asymmetries of the two cerebral hemispheres in man seem to be numerous. The interpretation of these asymmetries is difficult; some are likely to be related to functional asymmetries. In the future, the study of morphological asymmetries in routine neuropathology, in patients who have been submitted to detailed neuropsychological examination, would appear to be desirable.


Electron microscopic development of neuroglia in epiretinal portion of post-natal rabbits. The development of epiretinal and optic nerve neuroglial cells has been studied ultrastructurally in 1-20-day post-natal rabbits. Two morphologically distinct neuroglial cells were observed, a dense "spider" type which is present from day one and a light-staining "crab" type of cell which appears on the 4th day in the epiretinal strip. "Crab" cells myelinate many axons and mature into typical dense oligodendrocytes. "Spider" cells have ultrastructural features of both astrocyte and oligodendrocyte and each cell also myelinates many axons. Many of these cells attach their processes to basement membrane of blood vessels and mature into a typical astrocyte. In 10-15-day-old animals these cells may be located at a distance of 15 micrometer or more from the axon which they enwrap. Most of these processes are sufficiently fine and tortuous to obscure the continuity in single thin sections from adult animals.


The neurological basis of motor asymmetry following unilateral 6-hydroxydopamine brain lesions in the rat: the effect of motor decortication. The role of the motor cortex in the mediation of asymmetric movement after unilateral 6-hydroxydopamine (6-OHDA) brain lesions has been examined in the rat. The effect of unilateral and bilateral sensorimotor decortication upon spontaneous and drug (apomorphine and amphetamine)-induced motor asymmetry has been studied following unilateral injection of 6-OHDA into the lateral hypothalamus. Both bilateral decortication and unilateral decortication on the side of the 6-OHDA lesion caused a transient reversal of the spontaneous motor asymmetry normally seen in 6-OHDA lesioned animals. Neither unilateral nor bilateral sensorimotor decortication abolished drug-induced turning behaviour. It is postulated that subcortical basal ganglia efferent pathways may be involved in the mediation of motor asymmetry after unilateral 6-OHDA lesions of the nigrostriatal dopaminergic projection.


Incorporation of amino acids into protein in different brain areas of rat, subjected to enriched and restricted environment. The incorporation of [14C]valine into acid-insoluble brain material from rats living in enriched and restricted environment, respectively, was studied. Quantitative estimations showed higher incorporation into brain protein of frontal, entorhinal, cerebellar and visual cortex and the hippocampus in enriched environment animals compared to restricted environment animals. This finding was confirmed by autoradiography.


Somatosensory evoked potentials. Diagnostic criteria and abnormalities in cerebral lesions. In order to advance the practical application of measuring evoked cortical responses following electrical stimulation of the median nerve at the wrist (SEP) in clinical neurology, diagnostic criteria, consisting of the onset latency, peak latency and 2 indices of the first 3 negative components, and their left-and-right differences, were proposed and applied to 65 patients with cerebral lesions of various aetiologies. The criteria used were shown to be very useful in distinguishing between normal subjects and patients with cerebral lesions. The N1 and N2 components were related to the involvement of sensory pathways and were commonly associated with sensory impairment of all modalities or of deep proprioceptive and cortical modalities. The N3 component, on the other hand, was related to the presence of lesions and non-specific sites as well as non-specific symptomatology. SEP, judged by the present criteria, was shown to be useful as a complementary diagnostic aid in localizing the sites of lesions in sensory pathways and in evaluating sensory function, especially when used in combination with clinical symptomatology.


Cause specific mortality of coal miners. The purpose of this study was to compare the cause specific mortality of the U.S. coal miner to the mortality of the total U.S. male population. A 10% sample was taken of those men covered by the United Mine Workers Health and Retirement Funds on January 1, 1959, and the resultant 23,232 miners were followed through December 31, 1971. The overall SMR was 102.1, and there was higher than expected mortality in several categories of nonmalignant respiratory disease, accidents and stomach cancer. The excess in stomach cancer occurred only for those men 70 years of age or older.


Utilization of medical information systems in American occupational medicine. A committee report. In an attempt to define the nature of medical programs and the extent of utilization of information systems in occupational medicine, a questionnaire was directed to 230 corporate medical directors of the largest employers in the USA. Responses were received from 163 (nearly 70%) of those contacted. While industrial injury data and sickness absence statistics are the principal areas of present computer analysis, respondents indicated that future plans called for a shift in emphasis to the analysis and correlation of human medical data with work exposure data. Nearly three-quarters of the respondents are planning more extensive medical information systems. It is concluded that there is an apparent need for both trained personnel to develop appropriate systems and enhanced communication between the users and suppliers of the required computer technology.


Degenerative joint disease in the mouse knee; histological observations. The knee joints from males of two strains (CBA/ORT and STR/ORT) were studied histologically. The incidence of degenerative joint disease was very high in the STR/ORT strain. Degeneration of the cartilage invariably occurred first at the interface of the cruciate ligament and articular cartilage of the tibia. Lesions were only seen on the medial tibial and later the medial femoral condyles. Blocks of fibrillated, uncalcified cartilage were gradually lost across the condyle, leaving the tidemark as a secondary articulating surface. Meanwhile the subchondral bone thickened and erosion continued through the calcified cartilage into the underlying bone. A statistically significant relationship was found between the development of the lesion and (a) medial dislocation of the patella, (b) calcification and ossification of the medial collateral ligament. Patella dislocation gave rise to extensive cartilaginous and bony metaplasia of the synovial tissue. In joints with advanced degeneration there was often evidence of a slight lateral subluxation of the femur relative to the tibia.


The role of smooth muscle cells and hematogenous macrophages in atheroma. Two types of lipid-containing cells were found in diet-induced atheromata of rabbits. The cells of the first type contained little acid esterase activity, were situated mainly in the deep and middle layers of the intima and constituted the overwhelming majority of foam cells. The lipid contained in them was bulky, indicating inefficient lipid emulsification and metabolism. The cells of the second type were rich in acid esterase activity and were situated in the superficial layer of the intima, often in subendothelial rows. These cells contained lipid which was finely emulsified and present in much smaller amounts than the lipid present in the first type of cell. The localisation of the two types of cells, the observation that only the second type of cell exhibited marked AS-D acetate esterase activity and the study of Adams and Bayliss (1976) indicate that, while the cells of the first type are myogenous, the cells of the second type are hematogenous macrophages. It is proposed that relative insufficiency of acid esterase activity in the myocytes is an important factor in the formation of atheroma. The intense acid esterase activity in the macrophages may play a major role in the healing of atheroma and its transformation into a fibrous plaque.


Capillary telangiectasis of the brain in chimpanzee. The occurrence of capillary telangiectasis of the brain in a chimpanzee is reported. The telangiectases were multiple and diffusely scattered throughout the brain although the cerebral and cerebellar cortex were particulary affected. Hemorrhage into surrounding gliotic parenchyma was present. The were associated neuroligic sings, most significantly paralysis and convulsions, and the outcome was fatal. A Case of this nature has not previously been reported.


Degenerative joint disease in the mouse knee; radiological and morphological observations. Gross anatomical and radioligical techniques have been used to investigate the form and incidence of degenerative joint disease in the knee joint of an inbred strain of mouse (STR/ORT). The disease was seen radiographically as a thickening of the subchondral bone in the medial tibial and femoral condyles predominantly in the males. In fresh and macerated joints only advanced lesions could be seen with light microscopy and these appeared as concave (tibial) or flattened (femoral) erosions with hard shiny eburnated surfaces. Medial patella dislocation was a common feature of the arthrotic joints and there was associated widespread periarticular heterotopic calcification. These growths started as peripheral exostoses from the patella and as small loci of mineralisation within the synovial tissue but later enlarged into plaques of calcified tissue. Ossific centres within the menisci were present in all knees but became greatly enlarged in the osteoarthrotic joints. Calcification of the collateral ligaments occurred in non-arthrotic joints, especially laterally, but progressed to thick ossification in the medial ligament of arthrotic knees. Eventually all these enlarging sites of calcification and ossification began to fuse together, thus limiting the degree of movement of the joint. There was a statistically significant positive relationship between the severe arthropathy and (a) marked patella dislocation and (b) the presence of calcification in the medial collateral ligament.


The pathology of Sandhoff's disease.

The pathology of Sandhoff's disease. We have presented the morbid anatomy of a case of Sandhoff's disease and have attempted to outline morphologic differences which distinguish this entity from other GM2 gangliosidoses. Yet, it may be well to maintain a sceptical eye. The anatomic differences among Tay-Sachs disease and its variants are more quantitative than qualitative and are overshadowed by the similarities. For these reasons, a definitive diagnosis must rest with the biochemist. Nevertheless, if many bizarre MCB's are encountered, the enzyme defect may be expected to differ from that of classical Tay-Sachs disease and, when seen in endothelial cells, they favour Sandhoff's disease. More importantly, if prominent visceral storage is found, and especially if it extends beyond the reticuloendothelial system to involve such selective sites as the kidneys and pancreas, Sandhoff's disease should immediately come to mind. For the pathologist, it is this latter point which more readily sets apart Sandhoff's disease from related GM2 gangliosidoses.


The effect of inflammatory stimuli on the stroma of neoplasms: the involvement of mononuclear phagocytes. The phlogistic response of the stroma supporting a transplantable rat fibrosarcoma and the ability of animals bearing a neoplasm to mount an inflammatory reaction to non-specific stimuli were investigated. In the unstimulated neoplasm the concentration of macrophages in the stroma was similar to that of normal connective tissue. The mononuclear exudate induced by cotton pellets or glass coverslips implanted in the neoplastic tissue, however, was reduced when compared with that in normal connective tissues at both 7 and 14 days after implantation of these foreign bodies. Since the emigration of radioactively labelled monocytes in both inflamed normal connective tissue and inflamed stromal tissue in the neoplasm proved to be similar, the assumption has been made that neoplastic cells inhibit the local accumulation of the newly emigrated monocytes. This macrophage dispersing effect only occurs in the neoplasm and there is no systemic action. The only systemic effect detected is an anti-inflammatory action which was significant only between the 1st and the 2nd wk after transplantation of the neoplasm into neonatal recipients.


Cell death in developing skeletal muscle: histochemistry and ultrastructure. The histological, histochemical and ultrastructural features of cell death in the normal human foetus are described. The age range of the foetuses was 7 to 16 wk. Cell death was observed in all foetuses between 10 and 16 wk. On the basis of these findings it is suggested that disintegration of cell membrane may be a crucial factor in this process. Acid phosphatase activity and phagocytosis of cell debris are evidently not the main means of disposal of degenerate cell products. The possible relevance of cell death in embryogenesis for dystrophic processes is discussed.


LDH isoenzyme pattern in a meningioma with pulmonary metastases. The case is presented of an intraspinal meningioma in a 14-yr-old female. After surgical exploration pulmonary metastases became apparent. At necropsy the tumour had increased proportions of the cathodal isoenzymes LDH-4 and 5. This pattern has previously been observed in malignant meningiomas and may be used at the time of biopsy to assess malignancy.


Clinical and post-mortem assessment of the cause of death. Analysis of the clinical and post-mortem assessment of the underlying cause of death in 742 autopsies showed that over- and underdiagnosis cancelled each other out in the majority of the main diagnostic groups, so there was little difference in the total number of cases recorded in the different groups after clinical and post-mortem investigation. However, in the individual case the reliability of the clinical diagnosis varied greatly with the nature of the diagnosis and its degree of certainty. Reliability was for example high with clinically certain arteriosclerotic heart disease and low with cerebrovascular disease. Underdiagnosis of lung cancer is still a problem. Lack of interest in autopsy investigation may be reflection of lack of clinical involvement or therapeutic frustration rather than the use of sophisticated diagnostic procedures, as has been assumed by previous authors. It is suggested that the idea of selection of cases for autopsy should be replaced by selection of autopsies for microscopic investigation on the basis of the macroscopic post-mortem findings. It is suggested also that clinicians might profitably attend autopsies on patients in their sphere of interest that were not admitted under their care.


Apoptosis in the small intestine of zinc-deficient and fasted rats. The number of apoptotic bodies found in the small intestine of control non-fasted rats was low. Apoptotic bodies were found in the crypt region of zinc-deficient rats and were present in very large numbers in half the animals examined. Increased numbers of apoptotic bodies were found in the crypt and fundic regions of fasted rats. The failure of cellular DNA synthesis which may occur in both zinc deficiency and fasting is considered as a possible cause of cell death by apoptosis.


Scanning electron-microscope studies of the endothelium of aortic allografts in the rabbit: morphological observations. Segments of aorta were transplanted between male rabbits using a cuff technique for anastomosis. The endothelial surfaces of recipient and donor aortas were observed by scanning electron microscopy following silver staining and pressure fixation at 1/2, 5, 24, 48 hr and 10 and 20 days after transplantation. Five hours after transplantation the endothelium was intact and only occasional cells were adherent to the surface. After 24 hr the endothelium was still intact, but showed breaks and small holes in the intercellular junction. There were many round cells adherent to the surface and lying in the sub-endothelium especially in association with the holes. Light microscopy showed that the intima was packed with cells, but they had not penetrated the internal elastic lamella into the media. Twenty days after transplantation the outlines of endothelial cells were no longer discernible and the surface was carpeted by leukocytes, platelets and thrombotic material.


Synovial haemangioma of the knee: light and electron microscopic findings. Venous haemangioma of the synovium of one knee also involved adjacent, skin and muscle of the leg in a 4-yr-old girl. Phleboliths were seen in the knee on X-ray. Histologically, the synovium contained large venous channels and was laden with haemosiderin. On electron microscopy, the synovial cells were morpholgically most like synthetic (B) cells. Erythrocytes were ingested and broken down, stepwise, to siderosomes. The synovial cell cytoplasm also contained electron-dense punctate iron deposits. The synovial response appeared to represent chronic haemarthrosis.


Ultrastructure of Pharyngostomoides procyonis Harkema 1942 (Diplostomatidae). II. The female reproductive system. Several components of the female reproductive system of Pharyngostomoides procyonis, including the vitellaria and vitelline duct, ovary and oviduct, Laurer's canal, and Mehlis' gland and associated ducts, were observed with the electron microscope. Vitelline follicles contain cells in various stages of development. Mature vitelline cells contain membrane-delimited clusters of vitelline globules near the plasma membrane. Cilia are present in the vitelline duct. The ovary contains germ cells in various stages of maturation. Oogonia are found in the peripheral region. Mature oocytes contain numerous dense bodies near the plasmalemma. Also included in the cytoplasm of mature oocytes are "nucleolus-like bodies," myelin-like bodies, and mitochondria containing dense granules and few cristae. The epithelium of the oviduct is ciliated. Sperm are present in the oviduct and in Laurer's canal. Two types of secretory cells found in Mehlis' gland are described.


Metacercarial cyst formation in vitro of Echinostoma paraensei. Cercariae of Echinostoma paraensei Lie and Basch 1968 encysted normally in the presence of Biomphalaria glabrata embryo (Bge) cells in culture, partially in culture conditioned medium, and not at all in fresh culture medium alone. At the ultrastructural level the cyst is composed of 2 well defined regions. The outer cyst wall (OCW) is particulate to fibrous in nature, formed from secretory granules released from the cercarial tegument. Membranous scrolls or rodlets secreted from the subtegumental cystogenous gland cells are then added to this layer, forming the inner cyst wall (ICW). After 24 hr the cultured cyst is enclosed by a thin cellular capsule similar to that found around cysts in the snail host. The capsule also contains collagen fibers, not found elsewhere in Bge cell cultures.


Histochemical and thin layer chromatographic analyses of neutral lipids in Echinostoma revolutum metacercariae cultured in vitro. Excysted metacercariae of Echinostoma revolutum cultured in vitro in the defined medium, NCTC 135 supplemented with 20% hens' egg yolk, doubled their mean relative body area and showed significant sucker growth within 14 days. Histochemical Oil Red O staining showed neutral fat mainly in the excretory system of excysted metacercariae and in adults grown in the domestic chick. In vitro cultured worms showed neutral fat in the intestine, parenchyma, and excretory system. As detected by TLC the major neutral lipid fractions were free fatty acids for excysted metacercariae; free sterols for adults grown in chicks; and triglycerides, free fatty acids, and free sterols for cultured worms. Excysted metacercariae excreted free fatty acids into a nonnutrient incubation medium, whereas cultured worms excreted diglycerides, triglycerides, and free fatty acids into the medium.


Host-parasite relationships of Fasciola hepatica in the white mouse. VIII. Successful vaccination with culture incubate antigens and antigens from sonic disruption of immature worms. Mice were successfully vaccinated using culture incubate and sonicate antigens from 16-day-old flukes. Various injection schedules using the culture incubate antigen decreased challenge worm counts by 54 to 86%. The best results were achieved when the culture incubate was injected at 12 and 24 hr of incubation. Host mortality in the natural immunity controls ranged from 33 to 42%, and in the vaccinated animals from 12.5 to 25%. Functional antigens were present by 12 hr of incubation. A single immunizing injection with the sonicate antigen decreased challenge worm counts by 86%. Two immunizing injections with this antigen decreased challenge worm counts by 82%. However, the pathologic process in the liver was more severe than in animals that received a single injection.


Fascioloides magna in white-tailed deer (Odocoileus virginianus): observations on the pairing tendency. Fascioloides magna (Bassi 1875) was recovered from 227 of 312 (73%) white-tailed deer (Odocoileus virginianus) in southern Texas between 1971 and 1975. Deer from age classes more than 1 year old had infection rates of from 64 to 84%. Few dead flukes were found. Flukes occurred exclusively in the livers of infected animals and were paired in 256 of 301 (85%) fibrous hepatic capsules. The prevalence of immature flukes with an average of one immature per infected liver was similar in all age classes, suggesting a relationship between fluke pairing and maturation.


Besnoitia darlingi (Protozoa: Toxoplasmatinae): cyclic transmission by cats. Two of five opossums examined from the Kansas City area were found to be infected with Besnoitia darlingi. Inoculation of cysts resulted in acute lethal infections in mice and hamsters. Chronic infections with development of tissue cysts were obtained in mice by prophylaxis with sulfadiazine. Cysts were fed to cats and a dog which resulted in the shedding of isosporoid oocysts by cats. The prepatent period was 11 to 14 days. Unsporulated oocysts averaged 11.9 by 12.3 micrometer and sporulated in 48 to 72 hr. Mouse-to-mouse tramsmission was achieved by injecting triturated tissue containing cysts. This is the third species of Besonitia to be cyclically transmitted by cats.


Search for the presence of lectin-binding sites on Toxoplasma gondii. Evidence for the presence of carbohydrate on the surface membrane of Toxoplasma gondii trophozoites and on the cell wall of toxoplasma brain cysts was sought by fluorescent lectin staining. Using FITC-conjugated preparations of Concanavalin A (Con A), wheat germ agglutinin (WGA), or soy bean agglutinin (SBA), we have failed to obtain evidence for the binding of these lectins on the surface of T. gondii trophozoites. In contrast, the three test lectins bound effectively and specifically to the wall of toxoplasma brain cysts. Prefixation of cysts with glutaraldehyde or brief trypsinization of cysts did not affect the intensity of cyst wall fluorescence when stained with FITC-conjugated Con A, SBA, or WGA. The results are interpreted to indicate that whereas exposed Con A, SBA, and WGA binding sites are associated with the wall of toxoplasma brain cysts, such lectin-binding saccharide residues are not present on the surface of trophozoites in exposed or reactive form.


Experimental infection with Plasmodium chabaudi in rats: antigen and antibody associated with anemia and glomerulonephritis of acute infection. Rat-adapted Plasmodium chabaudi caused a syndrome characterized by hemolytic anemia, splenomegaly, and glomerulonephritis. All rats recovered and appeared normal after 4 weeks despite persistence of proteinuria. Serologic studies on the malarious rats revealed that the infection was associated with a soluble antigen which was present concurrently with antibody in plasma, in material eluted from blood cells, in extracts of kidney tissues, and in the urine. This antigen appeared to be identical with one extracted from P. chabaudi parasites and did not cross-react with antigens of Plasmodium gallinaceum. Tests for the cold-active hemagglutin (CAH) and the globulin associated serum antigen (SA) previously associated with acute malaria, revealed that CAH, but not SA, was present. From these observations it is suggested that soluble complexes of the parasite antigen and its antibody may have been causal in this syndrome.


The genus Speleocola lipovsky (Acari: Trombiculidae) with descriptions of two new species from Venezuela. Speleocola Lipovsky 1952 is redescribed. New species S. clangula off Rhipidomys sp., Venezuela, and S. nolae off Peropteryx kappleri, Venezuela, are described. A key to the 5 included species is given.


Establishment and characterization of a diploid cell line from the tick, Dermacentor parumapertus Neumann (Acarina: Ixodidae). Establishment of a continuous cell line (RML-14) from embryonic tissues of the tick Dermacentor parumapertus Neumann is reported. The culture medium employed consisted of a combination (2:1) of Eagle's and L-15 (Leibovitz) media supplemented with 20% fetal bovine serum, 10% tryptose phosphate broth, and 0.1% bovine plasma albumin. At the 8th passage, 99% of dividing cells had the female chromosome complement, among which more than 70% had a diploid chromosome number of 22. At the 13th passage, cell population showed approximately a 3-fold increase during the first 8 days of culture. As of December 1976, had been subcultured 40 times.


Cytology, reproduction, and sex determination of Strongyloides ransomi and S. papillosus. Parasitic females of Strongyloides ransomi and Strongyloides papillosus have 4 chromosomes and reproduce exclusively by mitotic (apomictic) parthenogenesis. The free-living generation includes females and males. The females have 2 pairs of chromosomes of unequal size and reproduce by meiotic parthenogenesis following obligatory pseudofertilization (gynogenesis). The males undergo spermatogenesis by the regular meiotic process and have the same chromosomal complement as the females. During prophase I, however, a portion of one homologue of the large bivalent breaks free and subsequently is diminished, as in S. ransomi, or it rejoins the original homologue, as in S. papillosus. This behavior of meiotic chromosomes during spermatogenesis suggests that the karyotype of these species has evolved from a karyotype analogous to that of Strongyloides ratti with 2 pairs of autosomes and a pair of X chromosomes, following fusion of the X chromosome with an autosome and the formation of a Neo-X and a Neo-Y chromosome. The female karyotype of S. ransomi and S. papillosus thus may be 2A + 2 Neo-X. The males are phenotypic males and have the same karyotype as the females, but their functional karyotype may be 2A + Neo-X + Neo-Y.


Repeated low-level infection of white-tailed deer with Parelaphostrongylus andersoni. Two white-tailed deer (Odocoileus virginianus) were given 5 infective larvae of Parelaphostrongylus andersoni each weekday for 13 weeks. At 23 weeks one of these deer and a control were challenged with single doses of 200 third-stage larvae. Repeated low-level infection of P. andersoni resulted in a sustained leukocytosis with an absolute eosinophilia which declined only after administration of larvae ceased, partial failure of worms to become established in the musculature, reduced numbers and reduced viability of eggs in the lungs, and an apparent active immunity which enabled the deer to resist challenge. The results of this study suggest that wild deer become infected with P. andersoni by isolated chance encounters with infected gastropods.


Transovarially-transmitted intracellular microorganisms in adult and larval stages of Brugia malayi. Observation of intracellular organisms in the lateral chords of Brugia malayi adults initiated further studies to determine the prevalence of these organisms within the tissues of adult worms and of larvae. The organisms were found in the lateral chords of adult males and females, microfilariae, first-, second-, third-, and fourth-stage larvae. In the females, they were present in the oogonia, oocytes, and developing eggs, suggesting transovarial transmission within the life cycle of the filarid. The organisms may have a developmental cycle consisting of more than one stage, including a small spheroidal stage up to 0.6 micrometer in size and a larger form up to 1.5 micrometer in length, all of which occur in the cytoplasm within a vesicle formed of host membrane. Each stage lacks a definite cell wall, being bound by 2 trilaminate membranes. The bacterial entities in B. malayi resemble both in morphology and development the organisms found in other filarids, but whether they affect the vertebrate host in any way remains to be determined. Their presence within certain cells of the developing eggs could be exploited as intracellular markers for the organogenesis of the lateral chords and the ovary.


Surgical repair of the injured spleen.

Surgical repair of the injured spleen. Fatal sepsis has been reported with increasing frequency following splenectomy for trauma. Efforts to save the spleen were made in 17 children with blunt abdominal trauma. Two patients required splenectomy, but 15 were managed successfully by splenic repair. No patient required reoperation, and there were no complications. Follow-up scans were remarkably normal. It is concluded that splenic lacerations are usually amenable to suture repair, and splenorrhaphy, not splenectomy, is the treatment of choice for splenic injury.


Replantation of the upper extremity in children. Since Malt and McKhann performed the first successful replantation of a traumatically amputated extremity in 1962, there has been a flurry of case reports and articles debating the pros and cons of the various technical aspects of replantation. There have been three case reports of children, under the age of 15, who have successfully undergone replantation of the upper extremity transected throught the humerus. The first case report in this article is the fourth. The factors involved in selecting replantation or amputation, and the technical aspects of the operation which are felt to be important, are briefly reviewed. Because the mechanics of limb replantation are rather straightforward, we feel that the pediatric surgeon should be familar with the preoperative and intraoperative factors to be weight, and that this alternative to stump closure be carefully considered when one is presented with an upper extremity transection.


Gastric volvulus in children: report of two cases. Two cases of gastric volvulus in children are reported, one acute and one chronic. The diagnosis should be suspected as an unusual cause of chronic recurring upper abdominal pain or in acute gastric obstruction. The radiographic appearances of these patients are presented. Anterior gastropexy has produced good results in both the patients described.


Aneurysmal bone cyst mimicking Ewing's sarcoma of the rib. A cantaloupe-sized intrathoracic tumor destroying the eighth rib with a pleural effusion is ominous. This case of an aneurysmal bone cyst of a rib mimicking a malignant chest wall tumor was both interesting and instructive.


Rhabdomyosarcoma of the bile ducts.

Rhabdomyosarcoma of the bile ducts. Rhabdomyosarcoma is a rare malignant neoplasm of the biliary tract. Including all the historical recent probable, and established cases that are carefully classified by Hayes and Synder, only 24 cases have been reported to date. Because of the extreme rarity of this tumor in this location, correct diagnosis was not made until second laparotomy or autopsy in several reported cases. The present report describes a child who recently underwent excision of such a tumor at our institution.


Presidential address: E pluribus unum.

Presidential address: E pluribus unum. To promote the best possible overall pediatric surgical care, I think that this may be the time that we should consider making common cause with other surgical specialists who work in the pediatric age range. This will need cooperative organization in our hospitals, medical schools, and on the national level. We now need a combined strong voice to deal with the large organizations through which the policies and the funding are being decided. We must now "hang together, or we (and our patients) may all hang separately".


The effect of various resuscitative regimens on hemorrhagic shock in puppies. Since shock secondary to hemorrhage is not infrequently encountered in the pediatric patient, a puppy model was devised to help measure and monitor cardiovascular and metabolic changes that occur before and after resuscitation from hypovolemic shock (mean arterial pressure of 50 mm Hg for 1 hr). Three resuscitation protocols were compared: whole blood (replacement:shed) 1:1, 5% albumin in Ringer's lactate 1:1; and Ringer's lactate 3:1. All dogs survived the experiment and responded similarly during the shock period. Thermal dilution cardiac output rose in all groups after resuscitation; however, in the Ringer's lactate and 5% albumin groups, cardiac output was statistically greater than that observed in the blood group. In all groups, pH and blood pressure approached but did not return completely to baseline levels after resuscitation. In addition, early resuscitation demonstrated a further decrease pH ("hidden acidosis") before it began to return toward normal as resuscitation progressed. This study suggests that the infusion of large volumes of Ringer's lactate or 5% albumin in Ringer's lactate are equally efficacious in the treatment of hemorrhage. However, 5% albumin seems to be preferable because it allows infusion of a smaller quantity of electrolyte solution with equivalent physiologic benefits.


Complications and sequelae of temporal artery catheterization in the high-risk newborn. One hundred high-risk newborns underwent a total of 115 temporal artery catheterizations using direct arterial exposure. Early catheter-related complications occurred in 10 patients: retrograde thrombosis of the posterior auricular artery (6), small area of skin slough at catheterization site (2), and positive blood cultures. (2). Twenty-five surviving infants were examined 6-10 mo after catheter removal: 5 patients showed scarring of minor cosmetic importance; 20 patients had barely perceptible incisional scars; and 21 patients had a return of pulsatile flow in the catheterized temporal artery.


Experience with in-service examinations of pediatric surgical trainees. A formal examination is an effective device for assessing certain aspects of a resident's competence. Participation by outside examiners is advisable. Generalizations on the basis of 2 yr of experience may be premature, however, the oral examination, strengthened by outside examiners and complemented by a written clinical problem-solving test, has provided insight into the candidates' abilities and into their progress from the first to the second year. In addition, this process has identified strengths and weaknesses in the training program, which has led to modifications of the surgical curriculum. It is concluded that comprehensive oral and written examination of pediatric surgical trainees at the completion of their first year and again at the end of their second year yields information that is of importance to the trainee and to the faculty.


Lower esophageal sphincter dysfunction in esophageal atresia: nocturnal regurgitation and aspiration pneumonia. The association between lower esophageal sphincter (LES) incompetence, gastroesophageal reflux, and recurrent pneumonia in patients who have undergone successful repair of esophageal atresia (EA) and tracheoesophageal fistula is demonstrated in this study. The efficacy of esophageal manometric examination in the evaluation of the LES in young children after EA repair is documented. This study also provides evidence that infants and children with LES incompetence associated with EA may have LES responsiveness to bethanechol. Once established by manometry, this responsiveness may be used to manage the patient until surgical repair would be advantageous.


Management of major hemoptysis in patients with cystic fibrosis. Although bronchoscopy remains the best definitive method for localization of the site of hemorrhage in patients who have massive hemopytsis, angiography remains an important adjunct to this localization. When combined with embolization of the bleeding bronchial artery, it is an effective method of therapy for the management of massive hemoptysis in patients with cystic fibrosis.


"Acquired" lobar emphysema: a complication of respiratory distress in premature infants. Ten premature infants with respiratory distress developed a type of pulmonary lobar emphysema that is clinically and histologically distinct from interstitial or congenital lobar emphysema. In eight patients emphysema was noted in the right lower lobe, while in two the left upper lobe was affected. Five infants exhibited nonresolution of the emphysema and an inability to be weaned from ventilator support. Lung scans in these five infants showed absent or markedly decreased perfusion of the involved lobe. Lobectomy was necessary. Postoperatively, their respiratory status improved and they were successfully weaned from the ventilator. Five premature infants with identical radiographic emphysematous changes had normal lung scans. These infants did not require lobectomy and were also successfully weaned from the ventilator. Radiographic changes of lobar emphysema in these five infants completely resolved. Pathologic changes in the excised lobes were characteristic of bronchopulmonary dysplasia and obstructive intraalveolar emphysema. The long-term effects of positive pressure ventilation, oxygen, and suctioning techniques directed toward the right lower lobe may play an important role in the etiology of "acquired" lobar emphysema.


Management of pulmonary insufficiency in diaphragmatic hernia using extracorporeal circulation with a membrane oxygenator (ECMO). Persistent fetal circulation (PFC) causes severe pulmonary insufficiency in patients who have demonstrated adequate lung function following diaphragmatic hernia repair. Patent ductus arteriosus (PDA) ligation corrects this condition, but carries the risk of sudden right ventricular failure. Pharmacologic reversal of PFC may be attempted, and if unsuccessful, prolonged venoarterial bypass becomes necessary to provide effective pulmonary support. PDA ligation can then be performed safely and maturation of the pulmonary vasculature allowed to occur. Pulmonary artery pressure monitoring is essential.


Pulmonary artery pressure monitoring in persistent fetal circulation (PFC). The use of the Swan-Ganz catheter to monitor pulmonary artery pressure in adults with cardiopulmonary failure has become commonplace. Our meager experience was with four neonates diagnosed as having persistent fetal circulation monitored by the use of this PA catheter. Tolazoline was infused directly into the pulmonary circulation via the catheter. Pulmonary artery pressure was temporarily reduced by tolazoline administration, with a marked increase in PaO2. More experience is required to define the role of the Swan-Ganz catheter in neonatal physiologic monitoring.


Increased meal-stimulated gastric acid secretion and serum gastrin after extensive small bowel resection in puppies. In six beagle puppies provided with vagally denervated pouches of the oxyntic gland area, the effects of massive resection of the small intestine on acid secretion and serum gastrin induced by feeding were studied. The enterectomies produced significant postprandial hypersecretion of acid and hypergastrinemia. A linear correlation existed between the increased acid output and serum gastrin level.


Laparoscopy in infants and children.

Laparoscopy in infants and children. Laparoscopy has been performed in 60 infants and children over a 32-mo period. Indications included: the problem of possible appendicitis, chronic abdominal pain, possible regional enteritis, possible biliary atresia, and liver biopsy. Fifty-two per cent of patients were spared laparotomy, while in 32% the need for operation was established. There were 2 errors in diagnosis, 3 failures, and 1 complication. Laparoscopy is considered to be a safe, effective, and economical diagnostic procedure that deserves wider application in the pediatric patient.


The use of glucagon in the diagnosis and management of illeocolic intussusception. Twenty-one of 25 episodes of ileocolic intussusception were successfully reduced by the barium enema hydrostatic technique supplemented by glucagon. No apparent serious complications occurred from the use of this drug. The comfort of the children and the ease of filling the colon and small bowel seemed enhanced by the glucagon.


Surgical manifestations of eosinophilic gastroenteritis in the pediatric patient. Eosinophilic gastroenteritis, an inflammatory bowel disease of unknown etiology, occurs in one of 10,000 admissions to this Children's Hospital. We had added 4 cases to the 11 retrieved from a literature review. The inflammation is characterized by mature eosinophils predominating a transmural process which may produce pain, obstruction, perforation, bleeding, or fistulae. All levels of the gastrointestinal tract are involved, but stomach (25.9%) and small bowel (66.7%) lesions are most common. Eosinophilia occurs in 61% of children and allergy in 13%. X-rays may demonstrate a diffuse or localized process. Operative intervention may be necessary to exclude tumors or regional enteritis, and at times to extirpate complications of local disease, but conservative therapy is the treatment of choice for this exacerbating-remitting disease.


Peritoneal drainage under local anesthesia for perforations from necrotizing enterocolitis. During 1974 and 1975, five newborn infants weighing between 760 and 1600 g developed severe intraabdominal complications of NEC due to necrotic bowel with perforation and peritonitis. Because these tiny neonates were very ill with sepsis and other severe medical problems, no attempt at laparotomy under general anesthesia was carried out. Instead, using local anesthesia, the contaminated peritoneal cavity was drained via a small incision, usually in the right lower quadrant. This permitted evacuation of air, pus, and stool. In all babies there was improvement evident in the abdomen within one wk, although two of the five newborns died from other causes. The three survivors are well and have normally functioning intestinal tracts 1-2 yr following surgery. One of these surviving babies developed a bowel stricture which subsequently required resection. We feel this method is preferable in the handling of the tiny sick neonate with a bowel perforation from NEC.


Differentiation of intramural ganglia in the dissociated rectosigmoid of the rat: an organ culture study. The distal rectosigmoid of the developing embryonic rat was studied on each gestational day from 12 to 21. Circular muscle was first recognized on day 16 and ganglion cells on day 17. When in vitro dissociated colon from as early as the day 12 embryo reached a maturational age of 17 days (embryonic age plus days in culture), circular muscle, ganglia, and peristalsis could be detected. This indicates that neuroblasts must have migrated to the indifferent mesenchyme before day 12 of gestation. Anti-nerve growth factor immunoglobulin-G ( IgG) did not inhibit differentiation of ganglia in vitro. As a result of this study we designed an in vitro assay that can serve as a useful means to study isolated ganglion cell development.


Biliary Atresia: histopathologic observations and reflections upon its natural history. Operative liver biopsies and specimens of the extrahepatic ducts and porta hepatis have been studied in 12 cases of biliary atresia. In all cases, the liver showed giant cell transformation and inflammation with mononuclear cells and neutrophils. Most had other features of neonatal hepatitis, including necrosis of hepatocytes. In the intrahepatic bile ducts of all cases but one, the hepatic ducts and glands at the porta hepatis, and in the extrahepatic ducts where epithelium remained, there was degeneration of the epithelium and intramural inflammation. In the ducts at the porta hepatis and in 6 of 8 extrahepatic ducts where epithelium remained, there was extensive mural fibrosis compromising the diameter of the duct lumens. Three cases showed the inflammatory changes distal to sites of closure of the extrahepatic ducts. These findings demonstrate that in biliary atresia, hepatitis, intrahepatic cholangitis, and sclerosing cholangitis of the extrahepatic ducts all interact to produce acquired obstruction to bile flow.


Quantitative estimation of ventilation in newborn infants using the impedance pneumogram. Impedance pneumography is potentially a non-invasive method of measuring infant tidal volumes. In order to evaluate the accuracy of impedance pneumography, eight healthy infants (weighing from 709 to 3506 grams) were randomly chosen and studied. Simultaneous measurements of tidal volumes were made by calibrated spirometry and by transthoracic impedance pneumography. The results were statistically compared. Transthoracic impedance pneumography provided a reliable estimate of tidal and minute volumes in these newborn infants.


Perception of hostility in the TAT as a function of defensive style. Groups of male and female students with high, intermediate, and low scores on Byrne's Scale of Repression-Sensitization judged the amount of hostility and the darkness of 10 TAT cards, including the blank. The groups' judgments for each card were expressed in terms of the statistic E, a non-parametric index of discriminability derived on the basis of the theory of signal detection. Subjects with low scores on the scale showed significantly lower E values for hostility (p less than .05), but not for darkness, than the other two groups. It was concluded that differences in sensitivity to affective stimulation underlie the dimension of Repression-Sensitization.


Multidimensional scaling of the TAT and the measurement of achievement motivation. Subjects rated all pairs of eight TAT cards and ten Rorschach cards for similarity. They were also scored for n-Ach using imagery scoring on stories to TAT cards. Two similarity dimensions were found for the TAT stimuli, identified as number of persons and degree of strong affect. Those high and low on need for achievement for both sexes differed significantly on degree of salience afforded to each dimension, those high weighting the affect dimension more, and those low the person dimension more. Dimensions of the Rorschach found by Wainer et al. (1976) were replicated, but did not discriminate individuals on need for achievement. The results are discussed in terms of the interpretation of the dimensions, the possible relationship of affect to achievement motivation, and the possible practical implications for the use and measurement properties of projective tests.


A measure of interpersonal dependency.

A measure of interpersonal dependency. Interpersonal dependency refers to a complex of thoughts, beliefs, feelings, and behaviors revolving around needs to associate closely with valued other people. Its conceptual sources include the psychoanalytic theory of object relations, social learning theories of dependency, and the ethological theory of attachment. A review of existing self-report inventories revealed none that adequately assessed interpersonal dependency. A new 48-item self-report inventory which assesses interpersonal dependency in adults was developed using a sample of 220 normals and 180 psychiatric patients. It was cross-validated on two additional samples. Three components of interpersonal dependency emerged: emotional reliance on another person, lack of social self-confidence, and assertion of autonomy. The relationship of these components with normals and patients was discussed, as well as with the concepts of attachment and dependency.


a comparison of the Bem Sex Role Inventory and the PRF ANDRO Scale. The Bem Sex Role Inventory and the PRF ANDRO Scales were administered to 158 (59 males, 99 females) undergraduates enrolled in an introductory psychology course. Data analysis was carried out by examining the amount of agreement between the BSRI and the PRF ANDRO Scale in terms of assignment of sex-role outcome. When both sexes are combined, only 66 of 158 (42%) subjects fell in the same sex-role category.


Relationships between the Test of Attentional and Interpersonal Style and psychiatric subclassification. Examined the ability of a self-report measure of attentional and interpersonal characteristics to discriminate between groups of psychiatric patients and normal controls. Seventy-eight psychiatric patients and 30 nonpsychiatric medical inpatients completed the Test of Attentional and Interpersonal Style (TAIS). Discriminant analyses of TAIS scores showed that: (a) psychiatric patients in comparison with normal controls described themselves as more overloaded by external and internal stimuli and as less effective in narrowing their attentional focus to task-relevant stimuli; (b) good premorbid schizophrenics appeared more externally overloaded and less able to narrow attentional focus than poor premorbid schizophrenics; and (c) psychotics and neurotics described themselves as more introverted and less pleasant in social encounters, while individuals diagnosed as character or personality disorders tended to be more extroverted and impulsive. The results were compatible with past experimental work and clinical reports identifying attentional and interpersonal differences among psychiatric subgroups.


The Eysenck Personality Inventory lie scale--some further Australian data. The lie scale of the EPI has been the subject of sparse and equivocal results. No age-related effects of the L scale have been reported. The scale is widely used in Australia as a screening instrument for entry into nursing schools. This study found significant differences in L scale performance between young and mature female nurses. This difference was demonstrated both in the higher frequency with which the mature group scored above the cut-off point for acceptance, and in the higher L scoring of this group even within the category of acceptable returns.


Inventory and expressive measures of locus control and academic performance: a 5-year outcome study. Inventory and expressive measures of locus of control were used in a effort to assess their long term potential for predicting academic performance. Thus 45 male graduate students from three diverse major areas and 45 male high ability undergraduates were initially administered Rotter locus of control and Autobiography locus of control scales. Academic data regarding grade point average and baccalaureal or doctoral degree attainment were gathered five years later. The hypotheses were supported to the extent that low to moderate significant correlations were found between the two locus of control scales and subsequent academic performance. The strongest relationships were found between locus of control and graduate degree attainment, with graduate student internals significantly more likely to earn the doctorate within 5-year period than externals. It was speculated that the externals might be a more persistent group, but the internals were more likely to either attain the degree within 5 years, or drop out. And within this study's restricted ability ranges, locus of control personality measures proved to be better predictors of degree attainment than conventional ability scales.


Can we describe an individual's personality? agreement of stereotype versus individual attributes. Group members described other members of their group (known for at least a year) by four different procedures (free-descriptive phrases, free-descriptive adjectives, an adjective checklist, and a rating scale) at weekly intervals. As expected, the agreement between pairs of observers, as measured by overlap of content, increased from the free to the structured tasks. However, observers, agreement by chance and on group stereotypes, assessed by counting overlap between their descriptions of two separate persons, also increased. When chance and stereotype-associated aggreement were subtracted from overall agreement, the remaining, "person-specific" agreement averaged about 5%. Agreement measured separately by a matching procedure averaged 14%. No significant increase in person-specific agreement was foud between the free-descriptive and standard tasks. The findings indicate that agreement on individuating features of a person is very low and is not appreciably improved by providing observers with standard descriptive tasks.


Long-term effects of a control-relevant intervention with the institutionalized aged. Elderly nursing home residents who were tested as part of an intervention designed to increase feelings of choice and personal responsibility over daily events were reevaluated 18 month later. Nurses' ratings and health and mortality indicators suggest that the experimental treatment and /or the processes that it set in motion had sustained beneficial effects.


Morphology and responses to light of the somata, axons, and terminal regions of individual photoreceptors of the giant barnacle. 1. The median eye of the giant barnacle, B. nubilus, comprises four large photoreceptor neurones which are visible under the dissecting microscope for almost their entire length. We have studied the structure of, and the responses to light recorded in, the somata, axons, and terminal regions of these neurones.2. The photoreceptor somata, each 40-70 mum in diameter, extend numerous light-sensitive dendritic processes whose membranes form rhabdomeric microvilli. Recordings from the soma show that dim light evokes a steady, noisy depolarization; brighter light elicits a transient depolarization which decays to a maintained plateau, followed by a hyperpolarization when the light is turned off.3. Light-induced voltage changes spread decrementally along the photoreceptor axons, which average 10 mm in length and 25 mum in diameter. In distal parts of the axon, near the presynaptic terminals, depolarizations and hyperpolarizations can be as large as 50% or more of their values in the soma.4. There is no demonstrable electrical coupling between photoreceptor neurones as shown by simultaneous recordings from two receptor somata or axons.5. Each photoreceptor axon enters the mid line commissure of the supraoesophageal ganglion, bifurcates, and arborizes in a restricted zone of neuropil in each hemiganglion. The large size of the terminal processes of these neurones and their characteristic cytoplasmic inclusions enable one to trace them with the electron microscope as they branch in the neuropil.6. The terminal processes subdivide and end in 1-3 mum diameter branches which are the sites of apparently chemical synapses. Vesicle-containing, presynaptic loci on these processes of the receptor cell are invariably apposed to two post-synaptic processes from cells as yet unidentified.


The organization of the salivary gland microcirculation. 1. The microvasculature of the rabbit submandibular salivary gland has been investigated employing in vivo microscopy, blood flow measurements, latex casts, microsphere injections and examination of fixed sections of the gland.2. Two principal microcirculations were distinguished in the living gland, one supplying the acini and the other the intralobular ducts. Parasympathetic nerve stimulation (2, 5 or 10 sec(-1)) elicited different responses in each of the two microcirculations. Flow in the capillaries around the acini slowed initially before increasing. In contrast, flow in the intralobular duct capillaries increased soon after beginning stimulation.3. In some experiments both whole gland flow and microvascular flow were monitored simultaneously. Whole gland flow increased at the same time as flow in the acinar capillaries was decreasing and as flow in the intralobular duct capillaries increased. Flow in acinar capillaries increased about 5 sec after glandular flow started to increase.4. These observations could be explained if either the vascular beds of the acini and the intralobular ducts were arranged in parallel or if arteriovenous anastomoses were to shunt the acinar circulation. No such anastomoses were found in latex casts made of the gland vasculature, and microspheres injected into the artery supplying the gland were not found in the venous effluent.5. The intraglandular distribution of microspheres was measured in histological sections of the injected glands to give an estimate of the distribution of blood flow between the duct and acinar microcirculations. At rest and during maintained stimulation about 55% of the blood flow passed through the intralobular duct microcirculations, whilst during this initial 15 sec of stimulation this proportion was increased to over 70%. This finding is consistent with a parallel arrangement of the two microcirculations.6. The conclusions drawn from these observations are that the duct and acinar microcirculations are arranged in parallel, that there are differences in the way the vasodilatation is mediated in these circulations, and that arterio-venous anastomoses play no significant role in this gland.


Passive signal propagation and membrane properties in median photoreceptors of the giant barnacle. 1. The light-induced electrical responses of barnacle photoreceptors spread decrementally along the cells' axons. The decay of the depolarizing and hyperpolarizing components of the visual signal was studied by recording intracellularly from single receptor axons of the median ocellus of the giant barnacle.2. The resistance of the photoreceptor neurone decreases markedly when the cell is depolarized with respect to its dark resting potential of -60 mV. This rectification results in differential attenuation of the depolarizing and hyperpolarizing components of the visual signal as they spread down the axon. Consequently, the visual signal entering the synaptic region is conspicuously distorted.3. Bathing the photoreceptor axons in sodium-free or calcium-free saline or in isotonic sucrose does not significantly affect the spread of the visual signal to the terminals. Thus the signal is not amplified by an ionic mechanism along the axon.4. Membrane characteristics of the photoreceptor for hyperpolarizing voltage changes were estimated from (a) the ratio of the amplitudes of the visual signals recorded simultaneously in the axon and in the soma, (b) the time constant, and (c) the input resistance of the cell. All three independent measurements are consistent with a length constant 1 to 2 times the total length of the cell (lambda = 10-18 mm) and an unusually high membrane resistivity of about 300 kOmega cm(2). This resistivity enables the receptor potential to spread passively to the terminal region.5. Electron microscopic examination of receptor axons reveals an investment of glial lamellae, but demonstrates neither unusual structures which would lead to a high apparent membrane resistivity, nor junctions between cells which would seal off the extracellular space. Thus the observed high resistivity appears to be an intrinsic property of the receptor membrane.


Changes in cardiac output and total peripheral resistance during the carotid sinus baroreceptor reflex in the pregnant rabbit. 1. The reflex cardiovascular effects of changes in pressure within the isolated carotid sinus have been examined in sixteen anaesthetized pregnant rabbits. 2. Comparison of the mean results at sinus pressures of 40 and 200 mmHg showed that heart rate fell by 32.1 beats min-1 and arterial pressure was reduced by 48.2 mmHg. Cardiac output, measured by thermal dilution, fell by 25.7 ml. min-1.kg-1 and total peripheral resistance was reduced by 0-292 mmHg. ml.-1 min. kg. 3. The corresponding changes previously reported in a group of seventeen non-pregnant female rabbits were a similar fall in heart rate of 34.5 beats min-1 but significantly greater reductions in arterial pressure of 69-8 mmHg and in total peripheral resistance of 0-432 mmHg. ml.-1 min.kg. However, the fall in cardiac output of 12.6 ml.min-1.kg-1 was significantly smaller. 4. These observations show that the smaller blood pressure response of the pregnant rabbit to alterations in sinus pressure is due to a reduced change in total peripheral resistance.


Properties of different functional types of neurones in the cat's rostral trigeminal nuclei responding to sinus hair stimulation. 1. Properties of neurones in the trigeminal nuclei principalis and oralis responding to movements of facial sinus hairs were studied in cats anaesthetized by I. V. infusion of pentobarbitone.2. Using electrophysiological methods trigeminal neurones were classified into primary afferent fibres, trigeminothalamic relay neurones, interneurones and other unspecified higher order neurones.3. When receptive fields of synaptically activated neurones were compared with those of primary afferent fibres, an often extensive convergence from first order on to higher order neurones was established. Out of 119 relay neurones six received input from one sinus hair only. Spontaneous activity was encountered about twice as often in synaptically activated neurones than in primary afferent fibres.4. The responsiveness of single neurones was unstable over time in about one fifth of the population and then the total number of impulses discharged in successive responses could vary by as much as 500%. Unstable responsiveness occurred sometimes alone but was often accompanied by marked changes in the size or the configuration of the receptive field. Such instabilities were observed in all kinds of synaptically activated neurones but not in primary afferent fibres.5. Afferent inhibition in relay neurones could be elicited from within the excitatory receptive field and appeared to be related to the activation of distinct receptor populations responding to specific stimulus parameters. Inhibition was also seen in interneurones following both mechanical stimulation of the skin and electrical stimulation of lemniscal fibre terminals in the contralateral ventromedial thalamus.6. The results are discussed and compared with previous findings about sinus hair representation in the trigeminal nucleus and the ascending lemniscal projection. The findings indicate that the concept of the ;static properties' of relay neurones is not adequate for all trigeminothalamic relay neurones and may require a critical reconsideration.7. It is suggested that the afferent input from sinus hairs is effectively controlled at the level of the rostral trigeminal nuclei. This control may affect the spatial input to relay neurones, the temporal components of their responses and the intensity dimension of their transmission capacity. It is postulated that by these mechanisms tactile information from the sinus hair system is modulated according to the instantaneous sensory requirements of the behaving cat.


Quantitative aspects of responses in trigeminal relay neurones and interneurones following mechanical stimulation of sinus hairs and skin in the cat. 1. Stimulus-response relationships in discharges of trigeminal relay- and interneurones were investigated in the barbiturate anaesthetized cat using controlled sinus hair or skin displacements.2. In comparison with discharges in slowly adapting primary afferent fibres the responses in all higher order neurones were considerably reduced in firing rate and often revealed modifications suggesting the interaction of mechanisms actively modulating the afferent input.3. In relay neurones with or without a tonic discharge component the ;dynamic on' response during a trapezoidal displacement of sinus hairs was found to be determined entirely or predominantly by the movement velocity and to be independent of the deflexion angle of a stimulus. In contrast, the static response in tonic relay neurones was determined by both the movement velocity and the displacement amplitude.4. Spatial summation of afferent input caused either only quantitative changes in the responses of relay neurones leaving the general discharge properties unaltered or caused both qualitative and quantitative changes in the responses.5. Interneurones consisted of two functional groups. In about 25% of them the responses were not or only slightly dependent on the intensity of the applied stimulus, often burstlike and of an all or nothing character. In the second group of interneurones the responses showed a quantitative dependence on the applied stimuli. In this group of interneurones responses often increased with the spatial extension of the peripheral stimulus revealing spatial summation of the afferent input.


Voltage noise observed in rods of the turtle retina. 1. Intracellular voltage was recorded from rods in isolated retinae of the snapping turtle, Chelydra serpentina. The voltage was observed during darkness or during uniform illumination of a large retinal area. During darkness the voltage fluctuated continuously about a mean level. The spontaneous fluctuation is termed ;noise'. During illumination the amplitude of the noise was reduced.2. The noise observed during darkness could also be reduced by injecting a hyperpolarizing current into the impaled rod. The noise could be increased by a depolarizing current. The component of the noise that could be altered by polarizing the rod is termed ;voltage-sensitive noise'.3. When voltage-sensitive noise was first minimized by a continuous hyperpolarizing current, bright light produced an additional decrease in the noise. The component of the noise that was eliminated by light, but not eliminated by the injection of current, is termed ;light-sensitive noise'.4. The power density spectrum of voltage-sensitive noise, G(v)(f), could be described by an equation of the form [Formula: see text] tau(M) was approximately 7 msec, which is in good agreement with an apparent membrane time constant of 5-8 msec. The largest value of alpha(v) was 2.1 x 10(-9) V(2) sec.5. The power density spectrum of light-sensitive noise could be described by an equation of the form [Formula: see text] tau(L) was approximately 200-300 msec. The largest value of alpha(L) was 8.0 x 10(-9) V(2) sec.6. The potential maintained during darkness could be altered by superfusing a retina with artificial media of different compositions. Depolarizing the rods by changing the extracellular calcium concentration from 1 to 5 mM increased the voltage-sensitive noise. A similar effect was observed after adding 2 mM lanthanum.7. In contrast, 5 mM cobalt produced a small hyperpolarization and suppressed the voltage-sensitive noise. Injecting a depolarizing current, after exposure to cobalt, re-initiated the voltage-sensitive noise. The ability to elicit voltage-sensitive noise in the presence of cobalt indicates that it was not of synaptic origin.8. The results are consistent with the noise present during dark being produced by two types of channel in the rod membrane. One is controlled by the phototransduction process; each individual channel of this type may be described as having a mean open time of 200-300 msec and a conductance of approx. 6 x 10(-13) Omega(-1). The absorption of one photon closes approx. 100-300 of these channels. The other type of channel is controlled by membrane potential; each individual channel of this type has a mean open time which is less than the membrane time constant of 8 msec.


The dynamics of the pi 1 colour mechanism: further evidence for two sites of adaptation. 1. The visual pathway that determines Stiles's Pi(1) colour mechanism was isolated by the auxiliary field technique and studied under dynamic conditions of light adaptation and recovery by threshold measurements.2. The time courses of adaptation to Pi(1)-equated short wave-length (mu </= 500 nm) and long wave-length (mu >/= 550 nm) fields are very distinct: a large and relatively long-enduring transient threshold elevation occurs at the onset of the long wave-length, but not of the short wave-length fields.3. Similarly, the time courses of recovery from Pi(1)-equated long and short wave-length fields are quite distinctive: a large and relatively long enduring transient (;transient tritanopia') occurs at the offset of the long wave-length, but not of the short wave-length fields.4. The wave-lengths of the fields which cause the adaptation transients coincide with those shown previously (Pugh, 1976) to combine non-additively with mu = 430 nm fields in effecting Pi(1) adaptation. The failure of the time course of Pi(1) adaptation to be spectrally ;univariant' combines with the failures of field-additivity to demonstrate that signals from the long and/or middle wave-length sensitive cones affect the adaptation state of the Pi(1) pathway.5. The adaptation transients are not observed in the pathways that determine Pi(4) and Pi(5). Thus, instantaneous signals from the middle and/or long wave-length sensitive cones are not the cause of the transients. Rather the cause must lie in the path by which those cones transmit their signals to the Pi(1) pathway or in the Pi(1) pathway itself.6. The off-transient can be diminished by adding an adequately intense short wave-length field to a long wave-length field that would normally cause it. The Pi(1) pathway must receive chromatically opponent signals.


Movement of labelled decamethonium in muscle fibres of the rat. 1. Tritium-labelled decamethonium accumulated in diaphragm muscles of the rat in vitro with a peak at the end-plate region and the distributions were fitted by Gaussian curves. 2. Prolonged wash in physiological saline (10 hr) produced some loss in radioactivity but no detectable spread of the labelled compound along the fibres, which indicated that the decamethonium was not in a mobile form. 3. Rats injected with labelled decamethonium showed radioactivity in the diaphragm muscles after 21 days. 4. A slow spread of the labelled compound along the fibres was detected, and from the widening of the Gaussian curves the apparent diffusion coefficient was 1.2 X 10(-8) cm2sec-1, which is less than 1/500 of that in free solution.


Sodium entry in rat diaphragm induced by depolarizing drugs. 1. An increased uptake of labelled sodium was found in the end-plate region of rat diaphragm following brief exposure to solution containing (24)Na plus carbachol (100 muM), with a wash in inactive saline. Tetrodotoxin (0.1 muM) was also present. Comparable results were obtained with decamethonium and suberyldicholine.2. With carbachol (100 muM) the influx of labelled sodium at the end-plate region was increased by a factor of at least three as compared with that at the end of the fibres.3. After entry the labelled sodium spread along the fibres with an apparent diffusion coefficient which was half that expected in the external solution.4. The dose-response curve for the effect of carbachol gave a half-maximal value of 72 muM.5. In muscles depolarized by potassium methyl sulphate the effect of carbachol on the entry of sodium was reduced although demonstrable.6. The entry of labelled sodium at the end-plate was maintained during prolonged exposure to carbachol (100 muM) or decamethonium (100 muM).7. The rate of entry of (24)Na obtained with carbachol, after corrections for the wash, was estimated as 1.5 x 10(3) ions channel(-1) sec(-1), measured over a period of 15 sec.8. Labelled decamethonium and labelled carbachol also accumulated at the end-plate region. After extrapolation to allow for the effects of the wash the entry of decamethonium when expressed as a clearance (pl. mg(-1) sec(-1)) was comparable to that of sodium, as expected if decamethonium and sodium enter through the same channels.


Synaptic actions of individual vestibular neurones on cat neck motoneurones. 1. Unitary synaptic potentials evoked by the activity of single vestibulocollic neurones were recorded by means of spike-triggered signal averaging in neck extensor motoneurones of decerebrate cats. Properties of the vestibulocollic neurones which produced the potentials were examined.2. Vestibulocollic neurones were first identified as projecting to the C3 grey matter by antidromic microstimulation within the C3 extensor motoneurone pool. The spontaneous or glutamate-driven activity of the vestibulocollic neurones was then used to trigger the averaging computer. In this way ten inhibitory and two excitatory neurones were identified (20% of neurones tested).3. Action potentials in local branches of vestibulocollic neurones were usually recorded in the vicinity of motoneurones. Mean orthodromic conduction time from the foot of the extracellular spike, recorded in the vestibular nuclei, that triggered the averager was 0.72 msec. Mean synaptic delay was 0.4 msec.4. I.p.s.p.s had a mean time to peak of 0.81 msec and were readily reversed by injection of hyperpolarizing current. These data, together with the shape indices of i.p.s.p.s indicate that they are generated proximally on motoneurones.5. All vestibulocollic neurones making synapses with motoneurones were monosynaptically driven by stimulation of the ipsilateral vestibular nerve. Four out of seven tested were inhibited by stimulation of the contralateral vestibular nerve (commissural inhibition).6. Two excitatory neurones were located in Deiters' nucleus or on the Deiters'-descending border. Inhibitory neurones were found relatively medially in the vestibular complex in the medial, descending and Deiters' nuclei.7. Vestibulocollic neurones acting on motoneurones were tested for axon branching to more caudal levels of the spinal cord with electrodes placed at C5-7. Both of the excitatory and two out of nine inhibitory neurones branched.


The variability of muscle nerve sympathetic activity in resting recumbent man. 1. Pulse synchronous bursts of multi-unit sympathetic activity was recorded from median or peroneal muscle nerve fascicles in fourteen subjects resting in the recumbent position. The neural activity was quantitated in terms of burst incidence, i.e. the number of bursts in the mean voltage neurogram/100 heart beats, during successive rest periods of 2-4 min.2. For each individual the burst incidence was fairly constant between different rest periods but the mean burst incidence varied widely between individuals, the range being from less than 10 to more than 90 bursts/100 heart beats.3. Simultaneous double nerve recordings were made on one subject from median and peroneal nerves and on eight subjects from the two peroneal nerves. There was always close similarity between the two records in such experiments regardless of which muscles the nerve fascicles innervated. When analysed separately the difference in burst incidence between the two sides ranged from 0.7 to 5.1 bursts/100 heart beats. The findings suggest that sympathetic neurones destined to skeletal muscles are subjected to a homogenous central drive and that contributions to the activity from ganglionic or segmental sources are of lesser importance.4. On seven subjects repeated recordings at rest were made with intervals of 3 weeks-21 months between recordings. In each subject mean burst incidences were similar in all recordings (range of differences 0.5-11.2 bursts/100 heart beats) suggesting an individually constant level of sympathetic activity in muscle nerves.5. For each individual the variability of burst amplitudes in the mean voltage neurogram was described by burst amplitude spectra. Most subjects had a relatively larger proportion of small than high amplitude bursts, but there was a tendency for more even amplitude distributions in subjects with high burst incidence. The finding may be an indication of interindividual differences in the average number of impulses/burst.6. It is concluded that the multi-unit recording technique can be used for comparisons of the level of muscle nerve ;sympathetic tone' between different subjects.


Postural effects on muscle nerve sympathetic activity in man. 1. Pulse-synchronous bursts of multi-unit sympathetic activity (MSA) were recorded in peroneal muscle nerve fascicles in eight healthy subjects when lying, sitting and standing. The sympathetic activity was quantitated by counting the number of bursts in the mean voltage neurogram/min. Postural changes were analysed by considering the total activity to be a product of the number of bursts in relation to the number of heart beats (burst incidence) and the heart rate.2. In lying there were large interindividual differences in total activity, but for all subjects the activity increased when going from lying to sitting and from sitting to standing. With a few exceptions the increase between the lying and sitting postures was associated with an increase in both burst incidence and heart rate whereas between the sitting and standing postures there was an increase in heart rate but on the average no change in burst incidence.3. When going from lying to sitting or from sitting to standing the magnitude of the change in burst incidence was inversely related to the initial burst incidence so that subjects with low initial values usually showed greater increases in burst incidence than subjects with high initial values. Some subjects with high initial values decreased their burst incidence.4. With changes in postures there was an inverse linear relationship between the fraction of the change in MSA associated with a change in burst incidence and the fraction associated with a change in heart rate. An increase in total activity could be obtained by changing only burst incidence, by increasing heart rate without changing burst incidence, or by appropriate changes in both parameters. The slope of the regression line was -0.53 indicating that for adequate postural compensation fewer additional bursts were required when the compensatory response involved an increase in heart rate rather than an increase in only burst incidence.5. It is suggested that an impairment of the ability to regulate heart rate will make subjects with high burst incidence in the lying position orthostatically more vulnerable than those with low burst incidence.6. Shortly after standing up one subject developed bradycardia and subsequently fainted. The nerve recording was maintained until the subject collapsed. During the initial bradycardia no sympathetic bursts occurred suggesting that the syncope was associated with an interruption of normal baroreflex feedback between blood pressure and sympathetic outflow.


Human tactile detection thresholds: modification by inputs from specific tactile receptor classes. 1. Human detection thresholds for a vibratory stimulus applied to the volar surface of the index finger were examined under conditions where afferents from specific tactile receptor classes were simultaneously activated from the thenar eminence. The experiments were designed to test whether stimuli which have been shown previously to induce afferent inhibition of ;tactile' neurones in the cuneate nucleus of the cat could modify human subjective performance in a tactile detection task. Conditioning stimuli to the thenar eminence were usually of three forms; steady indentation to engage slowly adapting tactile receptors; 300 Hz vibration to engage Pacinian corpuscles; and 30 Hz vibration to engage the intradermal, rapidly adapting tactile receptors which are thought to be Meissner's corpuscles.2. In ten subjects the mean detection threshold for a 30 Hz test stimulus in the absence of conditioning stimulation was 8.6 +/- 1.0 mum (S.E.). Detection thresholds were increased substantially in the presence of a 300 Hz, 100 mum conditioning stimulus (mean increase 11.1 +/- 2.0 mum), whereas minor or insignificant effects were seen with conditioning stimuli consisting of (a) 30 Hz, 100 mum (mean increase 1.4 +/- 0.8 mum), (b) steady indentation, 1.5 mm in amplitude (mean increase 1.3 +/- 0.7 mum) or (c) 300 Hz, 100 mum to the contralateral thenar eminence (mean increase 0.4 +/- 0.5 mum).3. The 300 Hz conditioning stimulus to the ipsilateral thenar eminence caused a marked increase in detection thresholds at all test stimulus frequencies over the range 10-450 Hz. The effects of the conditioning stimulation therefore operated on inputs from Pacinian corpuscles, which are responsible for vibration detection at 80-450 Hz, and on inputs from the intradermal, rapidly adapting receptors which are responsible for vibration detection at 10-80 Hz.4. The band width of conditioning vibratory frequencies which was effective at amplitudes of 100 mum in bringing about increases in detection threshold extended from 50-80 Hz to 300 Hz, the maximum tested.5. Whereas amplitudes of 1-2 mum produced clear increases in detection thresholds with conditioning stimuli of 300 Hz, amplitudes of > 200 mum were needed at 30 Hz.6. The observed elevations in detection threshold are consistent with an afferent-induced inhibitory action exerted at synaptic relays of the sensory pathway by tactile inputs arising exclusively or predominantly from Pacinian corpuscles.


Analysis of electrical noise in turtle cones. 1. Properties of the light-sensitive voltage noise in cones in the retina of the turtle, Pseudemys scripta elegans, have been studied by intracellular recording.2. Suppression of the noise by light was a function of the hyperpolarizing response of a cone but not of the size or pattern of illumination.3. Power density spectra of the noise were fitted in many cones by the product of two Lorentzians with characteristic time constants tau(1) and tau(2) averaging 40 and 7 msec respectively. The spectra of some cells were peaked and could be fitted by a resonance curve.4. Spectra in dim light exhibited decreased low frequency power. They could often be fitted by a product of two Lorentzians using the same value of tau(2) as used in darkness but decreasing tau(1) and the zero frequency asymptote. An e-fold reduction in tau(1) occurred with lights which hyperpolarized by 4-7 mV.5. Injection of hyperpolarizing currents of about 0.1-0.2 nA into weakly coupled cones reduced the noise, and also reduced the sensitivity to dim flashes.6. The variance-voltage relation during steady illumination of different intensities differed from cone to cone. Dim lights increased the noise in some cells and decreased it in others, but moderately bright lights which gave steady responses of more than about one third maximal reduced the noise in all cells.7. When the cell was transiently depolarized during the differentiated component following steady illumination, the noise was less than it was after prolonged darkness.8. In the after-effect of bright light, the time course of recovery of noise was the same as that of flash sensitivity and voltage. The noise was reduced e-fold for hyperpolarizations averaging 3 mV while for sensitivity this reduction occurred for 1.3 mV. For a given hyperpolarization the noise was lower during the after-effect than during steady dim illumination.9. When a series of dim flashes was delivered to a cone, no significant increase in variance over the dark noise was detected during the photo-response. This implies that each photoisomerization evokes no more than about 1.5 muV at the peak of the response in a coupled cone, corresponding to about 50 muV in an isolated cone.10. The elementary shot events underlying the noise are about 100 muV in amplitude in an isolated cone, have a characteristic time constant of 16-60 msec and reflect unit conductance fluctuations of about 16 pS (S, Siemen identical with Omega(-1)).11. It is concluded that the noise source is internal to the cones. We postulate that the noise arises from opening and closing of the light-sensitive ionic channels in the outer segment, and that in darkness there is a residual concentration of the blocking substance which on average closes up to about one third of the channels. It seems likely that the unit event involves a considerable number of blocking molecules and ionic channels.


A radiological study of gastric (abomasal) emptying in calves before and after vagotomy. 1. Gastric emptying has been studied in the conscious, standing calf by lateral radiography and fluoroscopy of radiopaque meals instilled into the abomasum before and after vagotomy. 2. Bilateral cervical vagotomy proved to be the only certain way of achieving total vagal transection. By instillation of milk into the abomasum through a cannula calves were maintained in normal, healthy condition for up to 36 days after vagotomy. 3. Motility of the antrum was not impaired by vagotomy so that some movement of gastric chyme to the duodenum occurred within minutes of instillation into the abomasum. Complete transference of the test meal was, however, delayed after vagotomy. 4. The greatest effect of vagotomy appeared to be on the abomasal body so that inadequate amounts of chyme were transferred to the antrum for pumping to the duodenum. 5. Delay in passage of contrast material through the intestine was related to delay in gastric emptying although vagotomy may have affected the intestine directly. 6. Following vagotomy the abomasum showed a resumption of normal motility and emptying after 7-29 days. This effect of vagotomy is similar to that seen in the simple stomach and is probably due to the establishment of intrinsic gastric control.


Analysis of the onset phase of olfactory bulb unit responses to odour pulses in the salamander. 1. A method for delivering odour pulses of controlled onset, steady plateau and abrupt termination, has been developed and applied to a single unit study of mitral cell responses in the olfactory bulb of the salamander. The pulses have been monitored during the experiments near the site of stimulation on the olfactory mucosa.2. Responses have been categorized as excitatory or suppressive based on the initial response to the odour pulse.3. Initially excitatory responses had sustained discharges near threshold. With increasing concentration, the discharge changed to a brief burst followed by suppression. The briefest latency of a unit response was 120 msec, using stimulation of medium concentration, after the start of the pulse; the majority of units appeared to be excited within 200-300 msec. Ramp stimuli gave increasing periods of excitation as the rise time of the odour front became less abrupt.4. Initially suppressive responses showed suppression at all levels of concentration. The majority of units appeared to have an onset of suppression about 300-400 msec after the start of the pulse.5. These basic responses, involving suppression or excitatory-suppressive sequences, can be correlated with some basic properties of the synaptic circuits in the olfactory bulb. The time courses of the initial responses appear to be within the time periods of the inhalation cycle of the salamander, and therefore may reflect mechanisms of processing of natural olfactory stimuli.


The entrainment of breathing frequency by exercise rhythm. 1. The incidence of entrainment of breathing frequency by the rhythm of exercise was detected by a cross-correlation of the two frequencies. 2. During moderate, steady-state exercise on a bicycle ergometer at 50 rev/min, eight of fifteen volunteers (53%) showed entrainment when pedalling speed was kept constant with a metronome, and three of fifteen volunteers (20%) showed entrainment when pedalling speed was kept constant with a speedometer. 3. At 70 rev/min, in a second group of fifteen volunteers, the results were nine of fifteen (60%) and five of fifteen (33%) respectively. 4. During moderate, steady state exercise on a treadmill, in a third group of fifteen volunteers, eight of 15 volunteers (53%) showed entrainment while walking, and twelve of fifteen volunteers (80%) showed entrainment while running. 5. It is concluded that the rhythm of exercise is likely to affect the rhythm of breathing and that this controlling factor must be considered during studies of breathing pattern in exercise.


Developmental changes in nephron number, proximal tubular length and superficial nephron glomerular filtration rate of rats. 1. Post-natal development of single nephron glomerular filtration rate, superficial proximal tubular length, nephron number and kidney weight have been studied in Sprague Dawley and in Wistar rats. 2. Superficial tubular length is a non-linear function of body weight or age. There seems to be a rapid growth until animals weigh about 150 g in Wistar rats. In this strain, growth is slower thereafter. This difference is not as evident in Sprague Dawley rats. 3. Nephron numbers increase over the same period at which rapid tubular growth occurs. 4. Sprague Dawley rats have somewhat fewer, but longer, proximal tubules than do Wistar rats. 5. In all animals weighing more than 100 g, SNGFR is linearly related to weight. For younger, smaller Sprague Dawley rats, the same linearity holds over the age range studied--older than 20 days of age. In Wistar rats, SNGFR relative to weight is less in young animals. 6. By relating SNGFR to total kidney GFR, evidence is obtained that maturation of renal function also involves a greater increase in filtration by superficial than by juxtamedullary nephrons.


The relation between tidal volume and inspiratory and expiratory times during steady-state carbon dioxide inhalation in man. 1. Ambiguities and discrepancies in the published descriptions of the patterns of breathing in man have been re-investigated.Steady-state hyperpnoea during rest was induced in normal subjects of both sexes by means of CO(2) inhalation, usually in high O(2), but sometimes in low (P(A, O2) approximately 200 and 55 torr respectively).2. The relations between mean tidal volume V(T) and mean times for inspiration T(I) and expiration T(E) were satisfactorily divided into lower and upper parts (ranges 1 and 2) in nineteen out of thirty-three experiments using an objective least-squares method, and polynomials were fitted separately to each of the following pairs of variables V(T,lower), T(I); V(T,lower), T(E); V(T,upper), T(I); V(T,upper), T(E).3. The breakpoints occurred when V(T) was about one third of vital capacity, but there was much variation between subjects.4. In range 2, V(T) was inversely related to both T(I) and T(E) and there appeared to be linkage between T(I) and T(E), all as described by Clark & Euler (1972). The relation suggested by Hey, Lloyd, Cunningham, Jukes & Bolton (1966) over range 2 was not confirmed.5. The main part of the relation described by Hey et al. (1966) is concerned with range 1. Here the relation between V(T) and T(I) was variable; slight, but significant negative correlation predominated. V(T) was, on the other hand, strongly and inversely related to T(E), and plots of (T(E) - T(I)) against V(T) over both ranges showed even less scatter. Hence (a) T(E) is probably related to V(T) through two mechanisms, one involving a link with T(I) and another prominent one being quite independent of T(I), (b) most changes of respiratory frequency in normal man are brought about by change of T(E) rather than of T(I), and (c) there is no region of constant frequency as implied by Clark & Euler (1972).


A quantitative description of the pattern of breathing during steady-state CO2 inhalation in man, with special emphasis on expiration. 1. Quantitative data on the pattern of breathing in normal men and women (Gardner, 1977) have been used to derive expressions that are based on known physiological mechanisms.2. The relations between the applied chemical drive to breathing (expressed as DeltaP(A, CO2) in high O(2)) and the several components of the volume-time patterns described in the companion paper were examined. Neither mean tidal volume (V(T)), nor mean inspiratory nor mean expiratory times (T(I), T(E)) were uniquely related to the chemical drive across the breakpoint, which could be demonstrated in two and suspected in the third of these plots.3. Mean inspiratory flow (V(T)/T(I)) was linearly related to P(A, CO2) over the whole range and, like minute ventilation (V), showed no breakpoint. The mean relation was V(T)/T(I) = 0.11 (P(A, CO2) - 35.2). V(T)/T(I) was highly correlated with V; in individuals with healthy lungs and under relatively stable conditions of compliance and resistance it may be accepted as a wholly inspiratory alternative to V as an index, on the efferent side, of the total prevailing chemical drive.4. The description of the relation between T(I) and V(T) was essentially the same as that of Clark & Euler (1972): in range 1, T(I) = either 1.29 - 0.07 V(T)or the constant 1.24 sec, and in range 2, T(I) = 0.65/(V(T) - 0.88) + 0.59.5. Expiration was described by an equation based on the inverse linkage between T(E) and chemical drive and the direct link between both mean and breath-by-breath values of T(I) and T(E): T(E) = pT(I) + q/(drive - r) in which p was 0.64 +/- 0.09, q was 11.1 +/- 2.64 sec. (torr CO(2))(-1) and r was -2.73 +/- 1.09 torr CO(2). All three parameters were necessary for an adequate description.6. It is argued that the first term of the T(E) equation represents influences related to lung volume exerted through the vagus, and that the second represents the effects of over-all chemical stimulation exerted through other pathways.