Life events before myocardial infarction. One-hundred and-twenty-one men between the ages of 35 and 65 who had been admitted to a Coronary Care Unit were interviewed within a mean of 2.3 days of that admission, concerning their experience of certain specified predesignated life events in the previous three months before myocardial infarction. Ninety-one of them who were proven to have sustained a myocardial infarction were randomly matched individually with 91 men from an industrial payroll for sex, age and occupational level. Both groups matched, as groups, on marital status and household size. Significantly more patients (p less than .01) than comparison subjects reported these life events in the three weeks before infarction, whether this was experienced acutely or in an anginal setting. Most events were apparently independent of patients' or comparison subjects control; these were reported significantly more often by patients, both during the entire 12 weeks prior to illness (p less than .01) and during the three weeks immediately before infarction (p less than .02). Methodological difficulties are delineated which hinder credence as to the role of life events before illness.


Hypersensitivity in the anterior median eye of a jumping spider. Changes in sensitivity of the photoreceptor cells of the anterior median eye of the jumping spider Menemerus confusus Boes. et Str. have been studied by recording electroretinograms (ERGs) and receptor potentials. The amplitudes of the responses (ERGs and receptor potentials) increase during repetitive stimulation, with a maximum increase at 3-5 s intervals. The sensitivity of the photoreceptor cell is greater for about 60 s following illumination (maximum magnitude at 3-5 s) than it is during complete dark adaptation. This phenomenon, which we call 'hypersensitivity', is lost within one day following surgery in physiological saline. Upon loss of hypersensitivity, the sensitivity decrease during light adaptation is greater than for the normal eye and the small increase of sensitivity following the onset of illumination observed for the normal eye is lost.


The effects of osmotic stress on the electrical properties of the axons of a marine osmoconformer (Mala squinado. brachyura: crustacea). In contrast to the depolarization observed in hyperosmotic media, exposure of peripheral nerve to hyposmotic conditions induced pronounced axonal hyperpolarization. It is suggested that this hyperpolarization resulted from increased potassium and chloride permeabilities which could assist axonal volume regulation in hyposmotic conditions. The hyperpolarization was readily reversible, but the spike-generating mechanism suffered irreversible damage at hyposmotic concentrations below 665 m-osmoles. It is suggested that this axonal damage contributes to the lethal effects of hyposmotic stress in this crustacean osmoconformer and, possibly, in some euryhaline osmoregulators.


Spirillum swimming: theory and observations of propulsion by the flagellar bundle. The hydrodynamics and energetics of helical swimming by the bacterium Spirillum sp. is analysed using observations from medium speed cine photomicrography and theory. The photographic records show that the swimming organism's flagellar bundles beat in a helical fashion just as other bacterial flagella do. The data are analysed according to the rotational resistive theory of Chwang & Wu (1971) in a simple-to-use parametric form with the viscous coefficients Cs and Cn calculated according to the method of Lighthill (1975). Results of the analysis show that Spirillum dissipated biochemical energy in performing work against fluid resistance to motion at an average rate of about 6 X 10(-8) dyne cm s-1 with some 62-72% of the power dissipation due to the non-contractile body. These relationships yield a relatively low hydromechanical efficiency which is reflected in swimming speeds much smaller than a representative eukaryote. In addition the Cn/Cs ratio for the body is shown to lie in the range 0-86-1-51 and that for the flagellar bundle in the range 1-46-1-63. The implications of the power calculations for the Berg & Anderson (1973) rotating shaft model are discussed and it is shown that a rotational resistive theory analysis predicts a 5-cross bridge M ring for each flagellum of Spirillum.


Passive exchanges during water vapour absorption in mealworms (Tenebrio molitor): a new approach to studying the phenomenon. The weights of single mealworms were continuously recorded at 20 degrees C during exposure to periods of constant humidity and to abrupt changes in atmospheric vapour pressure. Two exchange stages were recognized in each animal. Weight changes were either limited to slow losses, suggesting transpiration through the external cuticle, or showed more rapid humidity-dependent gains as well as losses. Rapid exchanges indicated that water was gained or lost through permeable barriers, from a fluid compartmet of significantly lower vapour pressure than the haemolymph, equivalent to about 90% R.H. Weight gains and losses during humidity changes provided evidence of a significant, passively exchanging fluid compartment located between the exchange surface and absorbing mechanism. Weight changes in faecal pellets following their elimination provide further support for a rectal site of atmospheric absorption.


Neuronal basis of a sensory analyser, the acridid movement detector system. III. Control of response amplitude by tonic lateral inhibition. 1. The Lobular Giant Movement Detector neurone (LGMD) of Schistocerca responds with spikes when small areas of the visual field change in luminance. Previous work has shown that changes of +/- 1 log 10 unit are enough to produce maximal ON and OFF responses. 2. Using a 5 degree test area, it is shown that the number of spikes generated by such a stimulus depends on the luminance of the surrounding area. When the surround is dark, the response is maximal; when it is brightly lit, the response is minimal. Intermediate intensities produce intermediate values of response. A X 2 change in response is produced by about 3 log 10 units change in surround intensity. 3. A bright annulus, with diameters of 10-5 degrees and 25-8 degrees, inhibits both ON and OFF responses when concentric with the 5 degree test area, but not when it is 30 degrees eccentric to the test area. The inhibitory effect shows no decrease after 4 min. 4. These results are interpreted to indicate a tonic lateral inhibitory network, sited peripherally in the optic lobe prior to the divergence of the separate ON and OFF channels found in the projection from the medulla to the LGMD. It is probably identical with that described for the lamina by previous workers.


Primitive nervous systems: electrophysiology of the pharynx of the polyclad flatworm, Enchiridium punctatum. 1. Electrical activity accompanying motor activity can be recorded from the excised pharynx of Enchiridium punctatum. Multiple stimuli elicit behaviour which consists of an initial aperture closure followed by extension and then peristalsis. If the stimulus parameters are increased the preparation bends from side to side instead of proceeding through the behavioural sequence. Bending appears to inhibit other movements differentially. 2. The conduction involved with peristalsis is polarized and proceeds in a proximal direction. 3. With stimulus intensities greater than those needed to produce the behavioural response an initial muscle potential (IMP) is evoked. The IMP is frequency sensitive. Maximum facilitation occurs within 100 ms and drops to 50% of maximum within 250 ms. 4. Conduction velocities of the IMP range from 0-05 m s-1 to 1-9 m s-1. Conduction velocities appear to increase with facilitation.


Rhythmic swimming activity in neurones of the isolated nerve cord of the leech. 1. Repeating bursts of motor neurone impulses have been recorded from the nerves of completely isolated nerve cords of the medicinal leech. The salient features of this burst rhythm are similar to those obtained in the semi-intact preparation during swimming. Hence the basic swimming rhythm is generated by a central oscillator. 2. Quantitative comparisons between the impulse patterns obtained from the isolated nerve cord and those obtained from a semi-intact preparation show that the variation in both dorsal to ventral motor neurone phasing and burst duration with swim cycle period differ in these two preparations. 3. The increase of intersegmental delay with period, which is a prominent feature of swimming behaviour of the intact animal, is not seen in either the semi-intact or isolated cord preparations. 4. In the semi-intact preparation, stretching the body wall or depolarizing an inhibitory motor neurone changes the burst duration of excitatory motor neurones in the same segment. In the isolated nerve cord, these manipulations also change the period of the swim cycle in the entire cord. 5. These comparisons suggest that sensory input stabilizes the centrally generated swimming rhythm, determines the phasing of the bursts of impulses from dorsal and ventral motor neurones, and matches the intersegmental delay to the cycle period so as to maintain a constant body shape at all rates of swimming.


Evidence for calcium inactivation during hormone release in the rat neurohypophysis. 1. A study has been made of the relationship between 45Ca uptake into and hormone release from isolated rat neurohypophyses incubated in vitro. 2. Hormone secretion is triggered by high-K (56 mM) but long exposure to the stimulus does not generate a maintained release of hormone. 3. When hormone release began to wane, addition of Ba of La increased hormone output which suggests that the decline in output did not result from depletion of the neurosecretory granules at the nerve terminals. 4. 45Ca uptake is enhanced in the presence of high-K concentration, but the initial high rate declines during long exposure to the potassium stimulus with a time constant similar to that of the decline in hormone release. 5. After a period of incubation in a K-rich, calcium-free medium, addition of calcium to the medium induced hormone release. The magnitude of this release was dependent on the time of exposure to excess potassium. 6. After inactivation of secretion, mobilization of internal calcium by means of a calcium ionophore increased hormone release.


Heart action of the freshwater bivalve Anodonta anatina during activity. 1. Heart action of Anodonta anatina (L.) was investigated by recording the electrocardiogram (ECG), heart impedance, and ventricular and pericardial cavity pressure during different aspects of the normal behaviour. The contribution of mechanical and nervous mechanisms in controlling changes in heart action is discussed. 2. Pressure recordings were generally more reliable than the other methods and it is suggested that pericardial pressure pulses indicate the stroke volume output of the ventricle. 3. During spontaneous periods of prolonged shell closure there was an initial small increase in heart activity followed by a large reduction in both heart rate and systolic pressure, indicating that total heart output was considerably reduced. When the shell reopened, heart rate increased very rapidly with an initial overshoot of the normal level; systolic pressure increased more slowly with no overshoot. 4. These major changes in heart activity appear to be associated with respiratory changes and are controlled largely by the nervous regulatory system, but some minor rhythmic variations in the amplitude of heart beat are probably caused by mechanical factors. 5. Characteristic patterns of change in heart action were recorded during burrowing. These appear to result from haemodynamic changes associated with the muscular movements of the digging cycle. Control of the heart by the nervous regulatory system is apparently of much greater importance in relation to respiratory control than in relation to the haemodynamic functioning of the fluid-muscle system in locomotion.


Modulation of Hydra attenuata rhythmic activity: phase response curve. We investigated the effect of photic stimulation on the frequency of Hydra attenuata column contractions. We used positive or negative abrupt light transitions, single or repetitive light or darkness pulses, and alternation of light and darkness periods. The main results are: (a) The frequency of the contraction pulse trains (CPTs) varies transiently in response to an abrupt variation of the light intensity. (b) CPTs in progress can be inhibited by different types of photic stimuli. (c) The response time to a single photic stimulus varies during the inter-CPT interval and depends also on the polarity of the stimulus. (d) The CPTs are entrainable with repetitive light stimulation of various frequencies. (e) Long-lasting variations of the frequency of CPTs occur after the end of a repetitive light stimulation. We suggest that the mechanism responsible for the rhythym of column contractions is quite similar to that on which other biological rhythmic phenomena are based.


Events following the infections of enucleate cells with measles virus. The development of measles virus (Edmonston) and SSPE measles virus (Horta-Barbosa) has been examined in enucleate BSC 1 cells. New antigen synthesis in measles virus infected enucleate cells has been demonstrated by fluorescent antibody, by the formation of extensive syncytia from enucleate cells alone and by analysis of polypeptide formation by polyacrylamide gel electrophoresis. All polypeptides formed in nucleate cells were also present in enucleate cells but the amount synthesized was reduced to around 20% of that in nucleate cells. There was also a significant reduction in the amount of antigen detected by fluorescent antibody in enucleate as compared to nucleate preparations. Examination of RNA synthesis in infected enucleate cells revealed only a marginal increase in acid-insoluble material. Titration of the output of infectious virus from enucleate cells infected at both 37 and 31 degrees C indicated a consistent reduction of almost two log units compared to nucleate cells. That the enucleate cells were capable of replicating input genome at these times was demonstrated by the successful growth of respiratory syncytial virus, both at 37 and 31 degrees C. SSPE measles virus grew to higher yield in nucleate BSC 1 than measles virus but there was again a reduction of more than two log units in enucleate cells. All polypeptides synthesized in SSPE infected nucleate cells were apparent in enucleate cells.


Homogenization-resistant and -susceptible components of tobacco mosaic virus replicative form RNA. When prepared from tissue frozen with liquid nitrogen, tobacco mosaic virus replicative form RNA (TMV RF) was uniform in size but when prepared by high-speed homogenization, or when TMV RF prepared with liquid nitrogen was homogenized, 80 to 90% of the RF broke into relatively discrete pieces. The unbroken RF was not fragmented by additional homogenization. The TMV RF components susceptible and resistant to breakage, respectively, were synthesized with similar kinetics in relation to length of labelling period, but the slightly more resistant component was synthesized during the early infection period. Both components were produced by different strains of TMV but leaves infected with cowpea chlorotic mottle or southern bean mosaic viruses yielded only RF resistant to breakage. TMV replicative intermediate RNA was also broken by homogenization. The occurrence of the two RF components may be of significance in the replication of RNA viruses.


Ortho- and paramyxoviruses from migrating feral ducks: characterization of a new group of influenza A viruses. Ortho- and parainfluenza viruses isolated from the cloacas of migrating feral ducks shot on the Mississippi flyway included three strains of influenza. A virus (Hav6 Nav1, Hav6 Nl, Hav7 Neq2) as well as Newcastle disease virus. One influenza virus, A/duck/Memphis/546/74, possessed Hav3 haemagglutinin, but the neuraminidase was not inhibited by any of the known influenza reference antisera. The neuraminidase on this virus was related to the neuraminidases on A/duck/GDR/72 (H2 N?), A/turkey/Ontario/7732/66 (Hav 5 N?), A/duck/Ukraine/1/60 (Hav3 N?) and A/turkey/Wisconsin/68. We therefore propose that the neuraminidase on this group of influenza viruses be designated Nav6. The A/duck/Memphis/546/74 influenza virus caused an ocular discharge in 1 of 5 ducks and was shed in faeces for 10 days; it was stable in faecal samples for up to 3 days at 20 degrees C. These results suggest that ecological studies on influenza in avian species should include attempts to isolate virus from faeces. Faecal-oral transmission is an attractive explanation for the spread of influenza virus from feral birds to other animals.


Xf phage invading the host cells with their protein coats. The Xf phage coat protein associated with infected cells could not be removed by washing with antiserum and tris-EDTA buffer. Although the infected cells were consecutively washed 6 times with tris-EDTA buffer, the ratios of parental phage 6H-DNA to 14C-protein were not changed. A considerable amount of the parental 14C-protein and 3H-DNA in the original ratio were detected in the membrane and the soluble cytoplasmic fractions of infected cells. The studies of the change in Xf 14C-protein and 3H-DNA incorporation into the host cells and their release showed that DNA and protein penetrate together into the host cells during the first 60 min after infection (p.i.). While virtually all parental DNA was conserved, re-utilized and released from the infected cell 60 min p.i., no apparent release of parental protein was observed. Approx. 40% of the parental protein became degraded and could be washed from the infected cell after 90 min; the rest of the parental protein remained and probably was re-utilized by the host.


On the regulation of protein synthesis in vaccinia virus infected cells. All eukaryotic mRNA species show a characteristic individual translational efficiency under conditions of restricted polypeptide chain initiation caused by an increase in the osmolarity of the growth medium. In vaccinia virus infected L cells or HeLa cells virus mRNAs can be grouped into classes on the basis of their relative labelling under standard and hypertonic conditions. Under the latter conditions, most of the "early" mRNAs possess very high translational efficiencies, most of the "intermediate" mRNAs show an intermediate efficiency and the most prominent "late" mRNAs show a translational efficiency which is lower than that of other virus mRNAs but still higher than the average cellular mRNA. Late in the infection cycle virus mRNAs with a relative low translational efficiency are preferentially translated under standard growth conditions whereas "early" virus mRNAs which are still present and which show a higher translational resistance to hypertonic conditions are not translated. These results indicate a unique translational control operating late in the growth cycle of vaccinia virus.


A rapid method for the quantitative study of RNA from canine distemper virus infected cells. Centrifugation through CsCl was used to isolate 32P-labelled RNA in a one-step purification procedure. The method is suitable for quantitative as well as preparative studies and appears to have considerable advantages over conventional methods of RNA extraction. We have used this procedure to investigate the RNA synthesized in Vero cells infected with canine distemper virus (CDV). We show that the combination of CsCl centrifugation and affinity chromatography on poly-U Sepharose provides a rapid method for isolating messenger RNA from virus infected cells.


Inhibition of vaccinia virus growth by the nucleoside analogue 1-beta-D-ribofuranosyl-1,2,4-triazole-3-carboxamide (virazole, ribavirin). Virazole or Ribavirin (1-beta-D-ribofuranosyl-1,2,4-triazole-3-carboxamide) inhibits the growth of vaccinia virus at a concentration ode to a certain extent in the presence of Virazole, the DNA fails to acquire resistance to deoxyribonuclease and virus particles are not formed. Reversibility of the antiviral effect occurs when the drug is washed out from the infected cultures or when guanosine at an equimolar concentration is added.


The use of contact B mode ultrasound in pediatric ophthalmology. It has been shown that an ultrasound system such as the Bronson-Turner Contact B Mode can be added, fruitfully, to the armamentarium of the individual pediatric ophthalmologist. It can be used quickly and precisely with an ophthalmological training and without patient discomfort or anesthesia no matter what the age. Valuable anterior segment information can be readily gained without a waterbath. Examples are shown of children with opaque media who were found to have congenital cataracts and congenital aphakia, microphthalmos, PHPV, retinal anomalies and ectatic coloboma.


Freeze-cleaved replicas of the anterior surface of the vitreous body in premature infants. An electronmicroscopic structure of the anterior vitreous surface of premature human infant cadavers at the age of six, seven and eight months demonstrated with replica technique is presented. A regular hexagonal structure has been found behind the center of the lens. Towards the equator of the lens this structure is losing its regularity and may exhibit the forms of pentagons, rectangles, etc. This is probably due to the technique applied in the preparation. In one case a "mixed type" of fibrillar structure appeared, the arrangement of which does not seem to fit into the present concept of the orientation of the collagen fibrils.


Strabismus in children with cerebral palsy. A group of 238 patients with cerebral palsy were identified of whom 108 could be studied through their charts. Only 20 of these patients had strabismus. Of this group, 10 received no surgical therapy. In these patients followed up to a period of four years, no evidence of significant change in the strabismic deviation was found. Patients who were treated by medical and optical means alone did not show evidence of improvement. Surgical therapy was effective in providing a cosmetically acceptable result. Surgery was performed between two and one-half and 13 years of age in eight patients, with an average age of surgery of 6.5 years. The results which we obtained are comparable to those obtained by others at an earlier age. It does not appear that the age of surgery affects the ultimate cosmetic nor functional outcome in children with cerebral palsy.


Aplasia of the optic nerve.

Aplasia of the optic nerve. A case of unilateral true aplasia of the optic nerve in an otherwise normal and healthy child is presented. Twenty-eight previously reported cases of aplasia have been reviewed and classified according to criteria which we have presented. Only six of these cases, including the present case, represent true aplasia, manifested by total blindness and complete absence of the optic disc and retinal vessels.


Recurrence risks for retinoblastoma: a model for autosomal dominant disorders with complex inheritance. The characteristics of retinoblastoma pertinent to genetic counseling are presented. Vogel's model for the inheritance pattern of the tumor is described and then used to derive recurrence risks for the important genetic counseling situations in retinoblastoma. The effect on the risk of the degree and number of unaffected relatives to the index case in a pedigree is quantified.


Comparative study of the surgical management of congenital esotropia of 50 prism diopter or less. Fort-nine patients with congenital esotropia of 50 prism diopters or less were selected at random. Twenty-five had bimedial recessions performed initially followed by bilateral rectus resections when needed. Twenty-four had recession/resections performed initially and when needed, were followed by the same procedure on the fellow eye. The average corrections obtained after first procedure and after second procedure were compared and analyzed. The results showed the initial procedures of both groups to be equally effective. The results obtained after the second procedure in the recession/resection group were significantly better. Therefore, it would appear that for the patient we have described, the most effective surgical approach is ultimately the surgical regimen of recession/resection followed by the same procedure on the fellow eye.


A new approach to the Hirschberg test.

A new approach to the Hirschberg test. Forty patients with horizontal strabismus were examined in order to establish a correlation between measurements obtained by the alternate cover under the amblyoscope and measurements made by passively placing the corneal reflex in symmetry of that of the fixating eye. In order to reduce errors, the pupils were constricted to two mms and a very intense and bright one mm corneal reflex produced. Both measurements were very similar and a correlation of r=0,94 was found. Accuracy was significant at the p=0,005 level.


Clinical picture and management of subperiosteal hematoma of the orbit. A subperiosteal hematoma was seen in a 14-year-old boy following a blow to his head during a car accident. The involved orbit exhibited exophthalmus and inability of the eye to move above the horizontal. X-rays revealed a hairline fracture of the skull and a hemotympanum was found on the injured side. A subperiosteal hematoma of the orbital roof was suspected. Needle aspiration of the blood from the orbital hematoma resulted in an almost immediate cure of all orbital and occular problems.


Juvenile glaucoma in the Rubinstein-Taybi syndrome. A 10-year-old retarded child was seen by an ophthalmologist because of strabismus. Examination of the optic nerve heads revealed cupping consistant with glaucoma and initiated a referral. The appearance of this girl, with flat-broad based thumbs and toes, small head, low set ears, high arched brows, antimongoloid slant to the eyes, high arched palate, associated with mental retardation, and strabismus suggested the Rubinstein-Tabyi Syndrome. Gonioscopy revealed a high iris insertion, while tonometry indicated mildly elevated pressures in the right eye. Examination of the optic nerve heads showed large glaucomatous type cups, more so on the right with compromise of the temporal rim. Trabeculectomy was effective in controlling the intraocular pressure in the right eye. The association of juvenile glaucoma with the Rubinstein-Taybi Syndrome requires that ophthalmic referral to assess glaucoma be an essential part of the evaluation.


Trabeculectomy for adolescent onset glaucoma in the Sturge-Weber syndrome. Two patients with adolescent onset glaucoma associated with Sturge-Weber Syndrome have been presented. Both patients were successfully treated with ab externo trabeculectomy. This procedure is suggested as an additional means for controlling the late onset glaucoma associated with the syndrome without provoking additional complications or deterioration. Early treatment is emphasized before the irreversible changes of chronic glaucoma become manifest.


Enucleations in Nigerian Igbo children.

Enucleations in Nigerian Igbo children. A series of 32 eyes enucleated from Nigerian Igbo children has been reviewed. Retinoblastoma accounted for 19 enucleations, both sexes being equally affected and most growth being far advance. The seven cases of known trauma were with one exception encountered in boys and involved mostly plant material. Inflammatory pseudotumor was seen in two girls during the first year of life and malignant lymphoma in a boy of 15 years. Corneal ulceration was responsible for enucleation in three boys, one of them being the aftermath of measles.


Experimental creeping muscle.

Experimental creeping muscle. Using healthy rabbits, medial and lateral rectus muscles were recessed. Classical Swann incisions, along with limbal incisions with and without conjunctival recession, were performed. The second variable of reactability of suture material, utilizing absorbable 6-0 chromic and nonabsorbable 6-0 tycron sutures, was tested. Using a 9-0 nylon marking suture for documentation of area of recession, anterior advancement could be accurately measured. Five months after surgery, the animals were sacrificed, and each muscle was examined. Regardless of incision perfored and regardless of suture type used, no anterior advancement of retroplaced muscles occurred.


Pediatric dosing considerations in ophthalmology. In almost all cases concerned with topically applied ophthalmic drugs, no distinction is made between adults and infants or children with regard to the concentration and amount of drug used. Even though maximal therapeutic effects are usually observed, there can be significant short- and long-term toxicity problems. Based on some modest assumptions it should be possible to reduce doses without sacrificing therapeutic effectiveness in infants and children up to three years of age. The overriding concern should be, however, potential toxicity problems which may exist  in infants and children, in particular the neonate, due to their low body weight and the fact that in most cases, more than 90 percent of an instilled dose in potentially available to act systemically. Total body surface area can be used as a measure for determining potentially toxic doses in children. Especially for potent drugs, with both short- and long-term manifestations, toxicity considerations may necessitate some sacrifice in therapeutic effectiveness of a given drug or switching to an alternate drug in order to insure a reduction in toxic side effects.


Giant hairy nevus: preventable cause of amblyopia. An infant with a congenital giant hairy nevus causing occlusion of the visual axis of the right eye is presented. The nevus was removed at the early age of three weeks because of concern that the child would develop deprivation amblyopia. Since such nevi can undergo malignant changes, early removal may be justified for that reason alone.


Ocular pathology of Lowe's syndrome in a female infant. The ocular pathologic findings are presented in a case of a female infant with clinical and biochemical evidence of Lowe's syndrome. A small but increasing number of reports suggest that the mode of inheritance is not always sex-linked. The ocular histopathologic findings in the present case parallel those previously described for this syndrome. While the pathologic findings in other systems are variable, it is thought that the constellation of lens and anterior segment changes are sufficiently characteristic to identify cases of Lowe's syndrome.


Atypical vertical retraction syndrome: a case study. A case of unilateral retraction of the eyeball in downward gaze as well as downshoot with the retraction when an outward horizontal movement of the contralateral eye was attempted has been introduced. The case has an exotropia with inability to adduct involved eye. The face turned to the left to minimize diplopia in the primary position. During the retraction, the lid widened slightly. An analyses by electrooculography and electromyography suggested that there was an abnormal neural connection between the vertical recti of the involved eye and the contralateral lateral rectus muscle. Co-contraction of vertical recti and loss of the reciprocal innervation were seen at the involved eye. Surgical treatment for exotropia, and total transplantation of vertical recti to the insertion of the involved medial rectus resulted in a slight reduction of the exotropia with the face straight, but not in the retraction as well as adduction and elevation of the involved eye. Based on the results, a central mechanism to produce above abnormality was described.


Electroretinogram and visually evoked cortical potential in Tay-Sachs disease: a report of two cases. The electroretinogram (ERG) and visually evoked cortical potential (VECP) were recorded in two cases of Tay-Sachs disease where diagnosis was well established: 1. ERGs of high amplitude and of normal wave form were recordable with prominent oscillatory potentials. Responses were always equal in both eyes. 2. VECPs were extinguished in both cases. These findings were interpreted as showing that Tay-Sachs disease is caused by the degeneration of ganglion cells in the nervous system and that the ganglion cells in the retina do not affect the ERGs of vertebrate animals.


Bilateral retinoblastoma and verbal intelligence. Sighted and blind patients with bilateral retinoblastoma were compared with their unaffected siblings on standardized tests of verbal intelligence. IQs of blind subjects were found to be significantly higher than those of their siblings while no such difference was noted between sighted subjects and their controls. It was concluded that the IQ superiority of the blind group is associated with blindness rather than with the disease.


The surgery and results following traumatic cataracts in children. Ninety eyes undergoing surgery for the removal of traumatic cataracts have been evaluated. In this group, the visual results relate to the coincident complications and amblyopia. Most commonly, they may be related to the extent of the preoperative trauma to the injured eye or to the age of the patient at the time of the injury. Forty-eight eyes (54%) achieved an acuity of 20/20 to 20/80 with 38 (42%) eyes achieving acuity of 20/20 to 20/30. A visual result of 20/80 or better was obtained in 12 eyes of the 29 patients six years of age or less.


Physiological mediation of attitudinal responses. A study was undertaken to try to ascertain the best model of the relationship between stimuli, physiological responses, and attitudes. Subjects were asked to indicate their attitudes toward various nations after having received various bogus information about how they responded physiologically to the stimuli. The results indicate the following: (a) In general, attitudes appear to be physiologically mediated; (b) physiological mediation of attitudes is strongest when prior knowledge about the stimuli is low but is independent of prior attitudes about the stimuli; (c) bogus physiological feedback does not seem to be verbally mediated; and (d) the most fruitful distinction between types of bogus feedback is between any feedback versus no feedback, not between change versus no change or between increase versus decrease in response.


Incidence of retinoblastoma in Malawi.

Incidence of retinoblastoma in Malawi. The annual incidence of retinoblastoma in Malawi seems to be two cases per 100,000 children under five or one case per 10,000 live births. A higher frequency of one case per 21,700 to 17,900 children under five or one per 4,340 to 3,580 live births has been found in the Zomba and Mangochi districts. Analyzing the cases according to sex and laterality, 61.1 percent of the unilateral cases were girls and 58.3 percent of the bilaterals were boys. Among boys, 33.3 percent were bilateral while unilateral involvement of the left eye was found in 19.1 percent. Among the girls, the frequency of bilateral cases was 18.5 percent while the unilateral involvement of right and left eye was nearly similar.


Sex typing and the avoidance of cross-sex behavior. This article presents evidence for the hypothesis that cross-sex behavior is motivationally problematic for sex-typed individuals and that they actively avoid it as a result. In particular, when asked to indicate which of a series of paired activities they would prefer to perform for pay while being photographed, sex-typed subjects were more likely than either androgynous or sex-reversed subjects to prefer sex-appropriate activity and to resist sex-inappropriate activity, even though such choices cost them money. Moreover, actually engaging in cross-sex behavior caused sex-typed subjects to report greater psychological discomfort and more negative feelings about themselves.


Arachnoiditis and VECP change.

Arachnoiditis and VECP change. A five-year-old boy presented with tuberculous meningitis and subsequently developed amaurosis with optochiasmatic arachnoiditis (OCA) late in the convalescent stage of the illness. The visual evoked cortical potentials were correlated with the decreased and improved postoperative acuity. The diagnosis and classification of OCA have been discussed with emphasis given to prompt neurosurgical treatment.


Congenital upper eyelid retraction.

Congenital upper eyelid retraction. This report describes a six-year-old boy born with a unilateral upper eyelid retraction resulting in mild exposure keratopathy. The fissure on that side was 4 millimeters larger and lagophthalmos was present. At the time of levator recession surgery, the muscle was found to have a restriction at the medial and lateral horns preventing downward excursion. This condition has some of the features of congenital orbital fibrosis and is postulated to have been due to an intrauterine infection or inflammation.


Sugars and sugar derivatives which inhibit the short-circuit current of the everted small intestine of the rat. 1. The short-circuit current of everted rat intestine supported on a perforated cannula proved to be stable for up to 3 hr and has been used to study competition between transportable and non-transportable sugars. 2. 4,6-O-Ethylidene-alpha-D-glucopyranose (ethylidene glucose) and 4,6-O-benzylidene-e alpha-D-glucopyranos (benzylinene glucose), two nontransportable inhibitors of the hexose transfer system in human erythrocytes, were found to reduce the short-circuit current generated by transportable sugars such as galactose or 3-O-methyl glucose. 3. These compounds were also found to reduce the basal short-circuit current established by the everted intestine in a sugar-free Krebs solution. Both types of inhibition approached saturation at the higher concentrations used. 4. Similar inhibitory properties were shown by mannose, a non-actively accumulated monosaccharide, and by the beta-disaccharides lactose and cellobiose. 5. It is suggested that this common pattern of behaviour is due to the ability of these compounds to react with the sites for active hexose transfer but without translocation by the system. The significance of the inhibition of the basal short-circuit current is briefly discussed in this context.


Manganese-dependent propagated action potentials and their depression by electrical stimulation in guinea-pig myocardium perfused by sodium-free media. 1. Propagated action potentials were recorded in right ventricular papillary muscles from guinea-pig heart while exposed to Na-free, Ca-free and Mg-free solutions containing Mn. 2. When Na was totally replaced by 95 mM-Mn the overshoot was about 45 mV while the resting potential was about -90mV. 3. The overshoot of action potentials was increased by about 20-30 mV per tenfold increase of Mn concentration over the range of 2-50 mM. 4. Similar increases of overshoots with increasing of Mn concentration also occurred in the presence of 0-6 mM-Ca. Increasing of Ca from 5 to 20 mM had little influence on the overshoot but shortened the duration of the Mn-dependent action potential in the presence of 5 mM-MN. 5 Mn-dependent action potentials were not depressed by 3 X 10(5) M tetrodotoxin but by La. 6. These results suggest that Mn passes through the slow inward current channel to generate the action potential seen under the Na-free condition. 7. The overshoot and duration of the Mn-dependent action potential decreased with stimulation. At stimulus frequencies (Hz) of 0-5, 0-2, 0-1, 0-017 and 0-0033 the overshoot of action potential in 5 mM-Mn Tyrode decreased by 0-5-1 mV per an action potential.  This depression of the action potential is explained by assuming intracellular accumulation of Mn.


Afferent sympathetic nerve fibres with aortic endings. 1. We recorded the electrical impulse activity of thirty-five single afferent fibres with aortic endings isolated from the third to the sixth left thoracic sympathetic rami communicantes of anaesthetized cats. The endings of each fibre were localized by mechanical probing of the opened aorta at the end of each experiment. 2. Twenty-four fibres had a single aortic receptive field. Eleven fibres had several and distinct receptive fields (from two to four): they were usually located in nearby aortic areas or, in addition, in other proximal portions of the arterial tree or in the adjacent pleura and connective tissue. 3. Twenty-nine fibres had conduction velocities ranging between 5 and 27 m/sec (Group Adelta), while six fibres had conduction velocities between 0-2 and 1-2m/sec (Group C). 4. The spontaneous impulse activity was in phase with the aortic pressure pulse and consisted of not more than one impulse per pressure pulse. It was increased during increases in aortic pressure and, conversely, decreased during decreases in aortic pressure. In vivo and post mortem studies showed that these mechanoreceptors had an impulse activity which rapidly adapted during sustained stimuli. They thus seem to signal pulsatile aortic stretch. 5. These aortic sympathetic afferents are likely to be part of a nervous pathway through which pressor reflexes, exhibiting positive feed-back characteristics, can elicited.


Anomalies of the retinal veins and their incidence. Nonaneurysmal anomalies of the retinal veins were studied in 1,400 consecutive locally and systemically healthy individuals whose ages ranged from eight to 66 years. The anomalies included veno-venous crossing, triconfluence, congenital dilatation, prepapillary loop, anomalous macular veins, and retinociliary vein. Excluding the last three, these anomalies are not at all rare. Hypotheses to explain the development of veno-venous crossings and the bifurcation of retinal veins are also presented.


"Tissue-drag" with polyglycolic acid (Dexon) and polyglactin 910 (Vicryl) sutures in strabismus surgery. The new absorbable synthetic sutures, polyglycolic and (Dexon) and Polyglactin 910 (Vicryl), are excellent sutures for strabismus surgery, but they have a bothersome tendency to attract adjacent tissue (tissue-drag). This difficulty is found especially with the 5-0 size suture, less so with the 6-0 size suture, and minimally with the 7-0 size suture. The presence and number of short, stubbly, protuberant strands (hooklets) seen on the surface of these sutures under high magnification correlates with the lack of ease with which the sutures pass through tissue. Other factors involved in tissue-drag include the crevices between braids in these sutures and the fiber-tissue friction due to the innate nature of the suture materials. Sutures which pass with ease through tissue, such as catgut and nonabsorbable sutures, are seen to have smooth surfaces under high magnification. Coating the 5-0 and 6-0 Dexon and Vicryl sutures to smooth their surfaces and reduce tissue-drag was ineffective with isotonic saline solution, minimally to moderately effective with glycerine and with methylcellulose and polyvinyl alcohol solutions, but highly effective with peanut and sesame oils. Though tissue-passage of Dexon and Vicryl sutures was much improved by coating with oil and entirely satisfactory, it still was not quite as good as with catgut. Clinically, the oil did not compromise the knot security or ease of handling of the sutures. No unusual postoperative reaction was seen with the use of the oiled sutures. Although oiling the synthetic absorbable sutures at time of surgery is effective, we recommend that suture manufacturers reduce the tissue-drag of synthetic absorbable sutures either by smoothing the surface in the manufacturing process or by developing an absorbable coating applied to the sutures during manufacture.


Influence of the sodium pump on intercellular communication in heart fibres: effect of intracellular injection of sodium ion on electrical coupling. 1. The effect of intracellular sodium injection on the electrical coupling between cardiac Purkinje cells was investigated. 2. It was found that an increase in the intracellular sodium concentration produces uncoupling in about 500 sec and increases the input resistance of the injected cell. Both effects were completely reversible. 3. Inhibition of the sodium pump by ouabain (6-8 x 10(7) M) also causes electrical uncoupling. 4. The decoupling of heart cells achieved by sodium injection was considerably accelerated in fibres treated with ouabain. 5. The influence of sodium injection on cell communication seems to be related to the intracellular calcium concentration 6. The above results indicate that the maintenance of a low intracellular sodium concentration by the sodium pump is essential for the preservation of a high junctional conductance in cardiac fibres.


The force generated by a visceral smooth muscle. 1. Strips of taenia coli from the caecum of the guinea-pig were mounted in an organ bath at 37 degrees C; isometric contractions were elicited with 10(5)M carbachol. Each taenia was stretched to the length at which it produced the maximum active tension; it was then fixed and embedded for measurement of the transverse sectional area. 2. The maximal force produced ranged between 96-1 and 138-3 mN. This corresponded to a force of between 251 and 513 mN.mm(2) (mean: 416 +/-28 [n = 10]). Temperature changes in the range 23-38 degrees C had little effect on the maximal force output.3. When allowance is made for the extracellular space (about 32% of the transverse sectional area), for the non-muscular cells present in the taenia (about 5%), and for the non-contractile material present in the muscle cells (about 10%), the maximal force generated was about 734 mN.mm(2) of contractile material (or almost twice as large as in skeletal muscle).4. Electron microscopy revealed terminal apparatuses at the ends of muscle cells, anchoring the cells to the connective tissue, and cell-to-cell junctions (attachment plaques). In addition, many dense patches of dense bands, sites near the cell surface where filaments are seen to end, were scattered along the entire length of the muscle cell and lay close to bundles of collagen fibrils. 5. It is suggested that the production of such a large force by this smooth muscle is partly explained by the lateral attachment of some contractile units to sites along the entire cell length, which in their turn are anchored to the collagen network; the latter may be considered a sort of intramuscular tendon.


Spatial properties of horizontal cell responses in the turtle retina. 1. Intracellular recordings were made from horizontal cells in the retina of the turtle Pseudemys scripta elegans. Spatial properties of the responses were determined using brief flashes of monochromatic light. 2. For a light stimulus in the form of a long narrow slit the peak response decayed approximately exponentially with displacement from the centred position. 3. With variation in the area of a centred circular patch, the peak response increased in a graded manner with stimulus area but was not proportional to area. 4. The model of electrical coupling in the horizontal cell layer proposed by Naka & Rushton (1976) was applied to the results. For the case of dim illumination a simplification is applicable, and the voltage distribution for circular and slit-shaped patches of light can be expressed in terms of two unknowns: the voltage resulting from diffuse illumination and a characteristic 'length constant'. 5. The measured variation of response amplitude was well described by the theory. Measured length constants were distributed from less than 100 mum to greater than 1 mm, and in a given cell the values determined by the slit displacement method and the area variation method were in reasonable agreement. 6. It is concluded that with dim illumination the model provides an accurate description of the voltage spread in the cells. Deviations were found to occur at higher intensities and possible reasons are discussed. 7. The implications of the model on the measurement of resistance changes during illunination are discussed.


The relation between intercellular coupling and electrical noise in turtle photoreceptors. 1. Intracellular recordings from cones and rods in the retina of the turtle, Pseudemys scripta elegans, revealed that in darkness the cell voltage fluctuated spontaneously about its mean level. The fluctuations were reduced during bright steady illmination of the cell often to a level close to that obtained with the electrode outside the cell where the noise did not change significantly during illumination. 2. The magnitude of the intrinsic dark noise (voltage variance in darkness minus voltage variance in strong light) varied widely from cell to cell. In the noisiest cones it was about 0-4 mV2 while in quiet cones it was often as low as 0-01 mV2. The noise appeared radom and could be fitted by a Gaussian probability density function. 3. The spread of voltage in the network of coupled photoreceptors was estimated by measuring the spatial profile of the response to a brief flash of constant intensity moved across the retina. For a light stimulus in the form of a long narrow slit, the peak flash response usually decayed exponentially with displacement from the centred position. 4. For maximum responses less than about 5 mV in cones, the length constant of exponential decay, lambda, varied from less than 10 mum to greater than 35 mum, and the values obtained in opposite directions were often unequal. Background illumination did not significantly change lambda. In cells with extremely narrow spatial profiles, an exponential fit to the decay could not be made reliably. 5. Occasionally the spatial profiles had definite secondary peaks. In the most pronounced examples in a red-sensitive cone and in a rod the maxima were separated by about 20 and 50 mum respectively; for each, one peak was approximately as sharp as the optical stimulator while the second was broader. 6. Cones with short length constants displayed high dark noise while cones with long length constants were relatively quiet. 7. Three models of electrical coupling between cells were investigated: one based on a distributed network, one on a discrete square grid arrangement, and one on a discrete hexagonal array. Each model predicts a strong dependence of both noise and input resistance on length constant, and for tightly coupled cells each predicts that voltage variance is proportional to lambda-2. 8. The measured relationship between voltage variance and lambda in a large sample of cones was well described by both discrete models when the average cell spacing was taken to be approximately 15 mum. 9...


Transient inward current underlying arrhythmogenic effects of cardiotonic steroids in Purkinje fibres. 1. Voltage-clamp experiments were carried out in calf Purkinje fibres to determine the basis of transient depolarizations (TDs) associated with digitalis-induced arrhythmias. 2. Under the influence of strophanthidin, depolarizing clamp pulses were followed by a transient inward current (TI) which was small or absent in untreated preparations. The TI also appeared in the wake of a train of action potentials. 8. The TI can help generate spontaneous depolarizations in preparations showing the low voltage oscillations which often occur with advanced digitalis toxicity. 8. The TI can help generate spontaneous depolarizations in preparations showing the 'low voltage oscillation' which often occur with advanced digitais toxicity. It was designated TI because its magnitude and timing were appropriate to account for the TD. 3. Longitudinal voltage non-uniformity during the TI was determined with two voltage-recording micro-electrodes. Although the non-uniformity was not severe, the TI wave form was observed when the voltage difference signal was used to measure membrane current density. 4. Over the diastolic range of potential, the strophanthidin-induced TI appeared superimposed upon the normal pace-maker mechanism, the decay of a potassium current, iK2. The TI could be dissociated from iK2, however, by means of its unusual kinetic properties. 5. TIs could also be recorded at holding potentials positive to -55 mV, i.e. outside the range where iK2 deactivation occurs. 6. The TI amplitude showed a slow and strongly sigmoid dependence on the duration of the preceding depolarizing pulse. Stronger depolarizing reduced the TI amplitude, while slowing and exaggerating the sigmoid time-dependence. 7. Two clamp pulses in close succession gave additive effects in evoking a subsequent TI. This finding and the sigmoid time-dependence fit with previous observations that TDs are most prominent following a series of closely spaced action potentials.


On the analysis of nerve signals deduced from metacontrast experiments with human observers. 1. This paper reviews Alpern, Rushton & Torii's (1970a-d) derivation of the size of the inhibitory nerve signal arising from after flashes in the metacontrast experiment. 2. Their geometric argument is recast in terms of simple functional equations. This form of argument clearly displays the role of their assumptions in obtaining their main conclusion: nerve signal is linear in intensity over a range of 3-4 log units. 3. Two disadvantages of their approach are discussed. First, it is noted that in the presence of the data the assumption they employ in their analysis is logically equivalent to their conclusion. 4. Secondly, accepting their claim that the nerve signal generated by the after flash is linear over a broad range of intensities, and that this inhibitory signal simply cancels the excitatory signal of the test flash, leads to the conslusion that over this same intensity range the excitatory nerve signal is a power function with an exponent of close to two. This is incompatible with the suggestion that photoreceptor signals have been measured.


Circadian and other rhythmic activity of neurones in the ventromedial nuclei and lateral hypothalamic area. 1. The frequency of firing was simultaneously recorded from single neurones of the ventromedial nuclei (VMN) and the lateral hypothalamic area (LHA) in urethane anaesthetized rats for many hours. 2. There were circadian changes of VMN and LHA neurone activity. The pattern of this circadian rhythm is as follows: throughout the day LHA neurones show higher activity than that of VMN, as indicated by higher frequency and more fluctuations in their rates of firing. In late afternoon the discharge rate of LHA neurones increases further, showing oscillations of short duration. In the early evening hours LHA neurone activity gradually goes down, as the VMN neurones become active. Throughout the night, VMN neurones are more active than those of LHA, just the opposite of the day period. In early morning hours VMN neurones gradually become quiet, while LHA neurones begin to show activity. 3. Superimposed on the circadian rhythm, at certain periods of the day, VMN and LHA neurones showed short duration oscillations in rate of firing, roughly every 7-15 sec and every 3-5 min. 4. Activities in neurones of the VMN and LHA were reciprocally related; a decrease in firing rate of one was associated with an increase in the other. This phenomenon was shown clearly by analysis of auto- and cross-correlation functions of firing patterns of VMN and LHA neurones. 5. The effects of stimulations of the prefrontal cortex and splanchnic afferents on VMN and LHA neurones depended on the basic firing frequency, thus they varied with the time of day. Definite relationships exist between basic firing frequency of a cell and the magnitude of changes evoked by these stimuli. Reactions of VMN and LHA neurones were the opposite in most instances. Septal stimulations (at more than 10/sec) always produced inhibition of LHA neurone activity. 6. Intravenous injection of glucose inhibited LHA neurones and accelerated firing of VMN cells. This was true during the day period as well as at night when background activities of VMN and LHA neurones were different from that of the day. 7. Stimulation of the septal area with subthreshold pulses at a low rate (1-0.3/sec) suppressed or altered oscillations in firing frequency of LHA neurones. Severance of connection between LHA and structures caudal thereto had no effect on LHA neurone firing rates or rhythms. Sections between the septal area and LHA, however, abolished or greatly altered the oscillatory rhythms of LHA cell activity, although spontaneous discharges continued at a somewhat lower rate for periods of hours. 8. Stimulation of suprachiasmatic nuclei with weak intensity and low frequency also changed oscillatory fluctuations in firing of LHA neurones. 9. Possible origins of circadian rhythm and oscillations of short duration in firing pattern of VMN and LHA neurones were discussed.


Short-term synchronization of intercostal motoneurone activity. 1. The hypothesis is advanced that the joint occurrence of unitary excitatory post-synaptic potentials e.p.s.p.s) evoked in motoneurones by branches of common stem pre-synaptic fibres causes short-term synchronization of their discharge during the rising phases of the unitary e.p.s.p.s. 2. This hypothesis was tested using the pre- and post-stimulus time (PPST) histogram to detect synchronized firing among groups of intercostal motoneurones discharging in response to their natural synaptic drives. 3. Motor nerve action potentials were recorded monophasically from nerve filaments of the external intercostal muscles of anaesthetized, paralysed cats maintained on artificial ventilation. 4. Computer methods were used to measure peak spike amplitude, spike amplitude, spike interval and filament identification for simultaneous recordings from four filaments. The spike amplitude histograms were derived for each filament and groups of spikes were selected for analysis. 5. With spikes of one group designated as 'stimuli' (occurring at zero time) and those of a second as 'response' the PPST histogram was computed with different time bin widths. 6. With bin widths of 100 and 10 msec the central respiratory periodicity was apparent in the PPST histogram. With 1.0 msec bins the PPST histogram showed a narrow central peak extending to +/- 3.0 msec at its base. This 'short-term synchronization' supports the hypothesis of joint firing due to common presynaptic connectivity. 7. It was shown that detection of short-term synchronization was critically dependent on a sufficient quantity of data but that provided a simple criterion of adequate counts per bin in the PPST histogram was met, short-term synchronization could be detected between intercostal motoneurones of the same and adjacent segments.


Action potentials in the rat chromaffin cell and effects of acetylcholine. 1. Electrophysiological properties of the rat chromaffin cell were studied using intracellular recording techniques. 2. The resting potential in the chromaffin cell was -49 +/- 6 mV (mean +/- S.D., n = 14) in standard saline containing 10 mM-Ca whereas that in Na-free saline was -63 +/- 9 mV (n = 17). At rest, the membrane has a substantial Na permeability. 3. Action potentials were evoked by passing current through the recording electrode. In standard saline the major fraction of the action potential disappeared either upon omission of external Na ions from standard saline or addition of 1 muM tetrodotoxin (TTX). We conclude that action potentials in the chromaffin cell are due mainly to an increase in the permeability of the membrane to Na ions. 4. Small but significant regenerative action potentials were observed in Na-free saline, and when Ca in Na-free saline was replaced by Ba, prolonged action potentials occurred. We conclude that action potentials in the chromaffin cell also have a Ca component. 5. Iontophoretic application of acetylcholine (ACh) produced a transient membrane depolarization in standard saline. 6. Spontaneous action potentials were recorded extracellularly by microsuction electrodes. They occurred at a rate of 0-05-0-1/sec in almost all cells. 7. When the perfusion fluid contained 3 x 10(-7) M to 10(-4) M ACh the spike frequency increased up to about 2/sec. This stimulatory effect of ACh was blocked by 10(-7) M atropine but not by 10(-3) M hexamethonium nor by 10(-5) M-d-tubocurarine. 8. The importance of Ca entry during action potentials for catecholamine secretion is discussed


Behaviour and aeration of the respiratory system in the domestic fowl embryo. 1. The monitoring of developmental stage and under-water dissection were used to examine the initial aeration of the respiratory system in domestic fowl embryos. 2. A virtually complete absence of free air within the chorioallantois was found before the beak had begun to make 'beak-clapping' movements, even when the membranes were already draped over its tip. 3. During the 'beak-clapping' stage, but before the membranes were pierced and before respiratory movements had begun, many embryos were found to contain free bubbles of air within the trachea and air sacs. 4. All embryos in which the respiratory system was aerated were found also to have froth in the crop or other parts of the digestive system. 5. Air was found in both the respiratory and digestive systems of all embryos examined after membrane penetration by the beak. 6. When air was injected into the chorioallantois before the stage of initial aeration it was recovered 5 min later from both the respiratory and digestive systems in under-water dissections. 7. It is suggested that lung ventilation takes place in the avian embryo in three distinct stages: the major air-ways become aerated, then respiratory movements begin and lastly the tertiary bronchi are slowly aerated. It is suggested also that movements involved in the imbibing of fluids play a part in aeration before the membranes are pierced.


Physiological properties and receptive fields of mechanosensory neurones in the head ganglion of the leech: comparison with homologous cells in segmental ganglia. A study of the head ganglion of the leech was made to compare the properties of specific sensory cells in this ganglion with those of homologous neurones in the segmental ganglia. 1. In the head ganglion, cells were identified that had electrical properties, sensory modalities and adaptation properties similar to those of touch (T), pressure (P) and nociceptive (N) cells in the segmental ganglia. The cell bodies of these neurones were situated in characteristics positions that could be correlated with those in the segmental ganglia. Several lines of evidence suggested that they were primary sensory neurones. Fewer T, P and N neurones were identified in the head ganglion than would be expected from its six constituent segmental ganglia. 2. The receptive fields of identified T, P and N cells were situated on the external surface of the head and the interior of the mouth with considerable overlap. They were generally smaller in size than those situated on the main part of the body. The receptive fields were also displaced anteriorly so that some of them were situated in segments anterior to those of the innervating cells. 3. The morphology of the sensory cells in the head ganglion was studied by intracellular injection of horseradish perioxidase. The general branching characteristics of the cells and the structural appearance of their processes resembled those of homologous cells in the segmental ganglia. However, the routes taken to the periphery by some of the cells were not constant from head ganglion to head ganglion. This variability was confirmed by electrophysiological evidence, and differed from the constancy seen in segmental sensory cells.


Receptive fields, geometry and conduction block of sensory neurones in the central nervous system of the leech. 1. In segmental ganglia of the leech, the cutaneous mechanosensory neurones responding to to touch innervated the skin of their own segment and of part of the anterior and posterior adjacent segments. Each touch receptive field could be divided into three non-overlapping areas: a central part innervated by the branches of the cell which ran in the nerve roots of the ganglion containing the cell body, and anterior and posterior parts innervated by its branches which ran in the nerve roots of the anterior and posterior adjacent ganglia. 2. Impulses originating from the anterior and posterior parts of the receptive fields were susceptible to conduction block within the central nervous system when the touch cells fired repetitively at frequencies that could readily be elicited with weak mechanical stimulation. In contrast, impulses originating from the central part of the receptive fields were less susceptible to block. 3. The morphology of touch cells revealed by intracellular injection of horseradish peroxidase suggested that conduction block occurred at specific bifurcation points where small cell processes joined the main process. Different physiological experiments supported this conclusion. 4. In some touch cells, bifurcation points with particularly low safety margins of conduction operated as low-pass filters, limiting the frequency of impulses capable of invading certain branches. 5. The results suggest that mechanical stimuli which would likely be encountered by the animal can lead to conduction block within its central nervous system and as a result modify its integrative activities.


The thermal sensitivity of the polymodal nociceptors in the monkey. 1. The static and dynamic sensitivities to thermal and mechanical stimuli of polymodal nociceptors in hairy skin of the anaesthetized monkey have been investigated by recording activity in their primary nerve fibres. 2. Polymodal nociceptors responded to skin pricking, pinching and heating to temperatures higher than 40 degrees C. They did not respond to touch, stretch or cold. The conduction velocity of their axons was from 0.6 to 1.1 m/sec. 3. Three types of cutaneous receptive fields have been observed: single spot-like areas of 1-2 mm2; multiple spot-like areas of 1-2 mm2; and larger areas up to 25 mm2 with heterogeneous sensitivity. 4. Polymodal nociceptors were subjected to heat stimuli that commenced from a 33 or 37 degrees C adapting temperature. A series consisted of heating their receptive fields to 43, 45, 47 and 50 degrees C from one or the other adapting temperatures at a constant rate of 0.2 degrees C/sec. Each heat stimulus intensity was maintained for 4 min after which the skin was returned to the adapting temperature. Immediately after the first series the identical series was repeated in order to determine the effect of prior heating upon the dynamic responses to re-heating. The dynamic responses were characterized by three phases: an initiation of a discharge at a threshold level of skin temperature; a dynamic discharge during the suprathreshold change, that reached a peak frequency when the temperature reached its maximum; and an adaptation phase while the temperature remained at the high intensity. Adaptation was rapid initially, and then slowed during the final minutes at the high intensity. 5. Adapting the receptive field to either 33 degrees C or to 37 degrees C before the heat stimuli did not affect the sensitivity and the discharge pattern of the polymodal nocicpetors. 6. During the first series of stimulations, the threshold at which the individual polymodal nociceptors began to discharge to heat stimuli varied from 40 to 46.5 degrees C. The mean threshold of the population was 42.5 degrees C. 7. No change in the threshold was observed when responses to 0.2 and 1.5 degrees C/sec rates of heating were compared...


Live mass gains and wool production of merino sheep: three treatment programmes for parasite control. A trial is described comparing the live mass gains and wool production of three groups of Merino sheep treated either at four-weekly intervals, strategically or not at all for the control of helminths and Oestrus ovis during a 19 month period. The group treated at four-weekly intervals had the greatest gain in masass was not greater than that of the group treated strategically. At both shearings the four-weekly treated group produced more wool than did the strategically treated group. The latter group produced more wool in total than did the untreated group. The seasonal incidence of nematodes, cestodes and Oestrus ovis on the trial farm was determined by the slaughter of tracer lambs at regular intervals.


Immunization against coccidiosis in fowls. Immunity plays a major role in the control of coccidiosis. With the presently practised system of "protected exposure" under chemoprophylactic medication, problems are encountered because of seasonal variation in litter moisture and coccidial challenge. The alternative, "controlled exposure" or "vaccination" products a more solid immunity and more reliable results. This was found to be the method of choice in coccidiosis control in replacement pullets in the semi-arid subtropical climate of Rhodesia.


Subclinical septic bovine mastitis: critical evaluation of intramammary immunoglobulin therapy. A series of 152 quarters affected with subclinical staphylococcal and streptococcal mastitis was treated at random by intramammary infusion with one of 4 formulations containing inert solvent, specially prepared immunoglobulin (Ig) and antibiotics (penicillin G and streptomycin) in various combinations. The effect of treatment was measured by assessing the conversion of mastitic quarters to a normal or mastitis-negative state over a post-treatment period of 28 days. Considering the solvent as a placebo, solvent plus Ig had no significantly better effect than solvent only; solvent plus antibiotics gave results that were highly significant after 14 days even though about a third of the strains of S. aureus were resistant in vitro to one or both of the antibiotics; solvent plus antibiotics and Ig gave results that were highly significant during the whole 4 weeks after treatment. The Ig solution appeared to be considerably more effective against staphylococcal than streptococcal mastitis, but the small numbers precluded statistical analyses. It was concluded that use of the particular batch of Ig alone had no value in the treatment of the common forms of subclinical bacterial mastitis but that in combination with antibiotics the Ig had a somewhat better effect than was obtained with antibiotics alone.


The comparative incidence of subclinical bacterial bovine mastitis in 17 herds when using two sets of diagnostic criteria. On the single examination of 6804 quarter milk samples during a routine mastitis survey in 17 herds it was found that whereas 12,4% of quarters were diagnosed as subclinically mastitic when using the IDF standard set of diagnostic criteria, only 2,4% were positive when applying the additional criterium of a positive test for bovine serum albumin. The remaining 10% of quarters were then classified as being affected with septic inflammation of the ducts. The ratio of true subclinical septic mastitis to duct and test canal infections is recorded and the implications of the findings are briefly discussed.


Canine systemic lupus erythematosus. The disease, clinical manifestations and treatment. The similarities between human and canine systemic lupus erythematosus are enumerated, using the incidence of symptoms reported for man as a guide to the possible incidence of clinical signs in the dog. Differences between the human and canine diseases are listed. Four clinical cases of the disease are reported. Diagnostic procedures were confined to the observation of clinical signs and serological and haematological methods.


Canine tetanus.

Canine tetanus. A report of tetanus in a dog is presented. The symptoms were typical and the dog was successfully treated. The differential diagnoses and the therapy of tetanus are discussed with emphasis on the dose of antitoxin required.


A search for linkage in cystic fibrosis. Linkage between the locus for cystic fibrosis and other genetic markers was explored in 40 families from Birmingham and 20 from Manchester. No strong evidence was found for linkage with any of the markers examined. There was evidence against close linkage with ABO, HLA, and Rh.


A family study of coarctation of the aorta. Families of 100 patients with coarctation of the aorta and 50 controls for age, sex, and social status were studied to assess the influence of genetic and environmental variables in the aetiology. A tendency to familial aggregation of the condition and other congenital heart defects compatible with multifactorial inheritance was discerned. Recurrence risk for sibs is approximately 1 in 200 for coarctation of the aorta, and 1% for any form of congenital heart defect. The heritability of coarctation is estimated at 58%. The tendency for other non-cardiac defects to occur in the patients with coarctation does not appear in their sibs and is not so pronounced as in some other congenital heart conditions. Of the several environmental variables examined, there was no definitive association with any other than season of birth, which implies a possible association with maternal infection; there is also a suggestion of a paternal age effect, but these require investigation in a prospective survey.


Infantile cystinosis in France: genetics, incidence, geographic distribution. A national distribution of 66 French patients, from 49 sibships, has been studied. Segregation analysis, using the maximum likelihood method, was found to agree with the theoretical values expected in recessive autosomal inheritance. The birthplaces of these patients show an unequal geographic distribution of cystinosis, the incidence being higher in Western France. Compared with the total number of live births during the period 1959 to 1972, the minimum incidence of the condition in the province of Brittany is 1 per 25 909, and the gene frequency 0.0062. In the rest of France, the minimum incidence is 1 per 326,440 and the gene frequency 0.0018. Application of Dahlberg's formula gives a similar result. The mean inbreeding coefficient is 530 X 10(-5), a figure 23 times higher than the mean coefficient of France. An indirect test of inbreeding, the distance between parental birthplaces, was studied, first using the French administrative boundaries, second by using kilometers. This distance was constantly smaller for the parents of patients than for the parents of controls. Analysis of two erythrocyte polymorphisms (ABO and Rh) showed a large excess of group A patients when compared with overall French data. These findings are difficult to interpret on genetic grounds. The genetic reasons for the unequal geographic distribution of cystinosis in France are discussed.


Pyloric stenosis in the Oxford Record Linkage Study area. The files of the Oxford Record Linkage Study were employed to identify 220 infants presenting with infantile hypertrophic pyloric stenosis (IHPS) in the 6-year period 1966 to 1971. Information on these infants was obtained from birth certificates and maternity notes. The overall incidence was 2.5 per 1000 livebirths. There was a distinct seasonal variation, with highest incidence to infants born in the third quarter of the year as well as variation in incidence with area: the cities had much lower rates of IHPS than the adjacent rural or small urban areas. It was shown that the rates in the south and east of the area studied were far greater than in the north and west. In the present study there was no excess of primiparae, the peak maternal age group was 20 to 24; there was a slight excess of parents of social classes I and II; and a significant association with mothers who were Rhesus negative. The rate of IHPS among sibs was 85 per 1000. Though there was the usual correlation with the male sex (M:F ratio = 5.5:1), there was no variation with birthweight and only among the females was an association found with prolonged gestation. There appeared to be an inverse relation between gestation and age on admission to hospital.


Lowe's syndrome: identification of carriers by lens examination. Lens examinations were performed on 7 obligate and 7 possible carriers of the X-linked gene for Lowe's syndrome, and on 117 controls. By quantitatively grading punctate cortical opacities, it was possible to discriminate between the obligate carriers and the controls with a fair degree of confidence. In the age group most important for genetic counselling, that of child bearing, the data are too limited for the derivation of precise estimates, but may, nevertheless, be useful. More such data are needed.


Hereditary index finger polydactyly: phenotypic, radiological, dermatoglyphic, and genetic findings in a large family. Index finger polydactyly in a Turkish family is reported. The transmission of the malformation fits the pattern of regular autosomal dominant inheritance. Some of the affected individuals had one or two phalanges on their first digits, but all had triphalangeal second fingers. Subjects with polydactyly had very interesting dermatoglyphs, such as an extra a triradius under the super-numerary index finger, the proximal radiant of this triradius (an extra A-line) ending on the radial border of the hand, and arch tibials in the hallucal areas. The carpal bones, beginning with os multangulum majus, or alternatively with the extra one were articulated with two metacarpals. A similar finding was found in the feet.


Haemoglobin E Saskatoon beta 22 Glu replaced by Lys in the Shetland Islands. A survey of blood samples from the inhabitants of the Shetland Islands has revealed the presence of a variant haemoglobin in 1 individual out of the 345 tested. The rariant haemoglobin accounted for 46% of the total haemoglobin. Tryptic digestion and amino acid analysis indicated that the variant haemoglobin was caused by the substitution of a glutamic acid residue at position 22 in the beta chain by a lysine residue. This is the same amino acid substituion as found in haemoglobin E Saskatoon.


Dicentric X isochromosomes in man.

Dicentric X isochromosomes in man. Four cases of Turner's syndrome are presented in which an apparent X isochromosome i(Xq) has been found to possess two regions of centromeric heterochromatin. It is suggested that these chromosomes were isodicentric structures capable of functioning as monocentric elements as a result of the inactivation of one centromere. The prevalence of mosaicism is believed to be a consequence of the dicentric nature of these chromosomes, and it is considered possible that a high proportion of X isochromosmes are structurally dicentric. Banding patterns showed that the exchange site involved in the formation of the dicentric chromosome was different in at least three of the cases.


Severe mental retardation in a boy with partial trisomy 10q and partial monosomy 2q. A severely mentally subnormal child with many physical stigmata was shown to have the karyotype 46,XY,-2,+der(2),t(2;10)(q31;q24)pat. Full evaluation of this patient's karyotype depended on the family studies. It was shown that a balanced translocation t(2,10) was present in 4 normal males in 3 generations.


Atypical serum cholinesterase in a family with congenital distichiasis. This paper describes the coexistence of genetically determined reduced cholinesterase activity and congenital distichiasis in the same family. The pedigree suggests that these two autosomal dominant diseases are segregated independently and do not show evidence of linkage.


Triple X female and Turner's syndrome offspring. A mentally retarded young female having 47 chromosomes with a triple X karotype produced a child with Turner's syndrome associated with mental defeciency. To our knowledge this is the first example of a triple X female giving birth to a child with Turner's syndrome.


Renal function studies in an infant with 4p (-) syndrome. An infant with the syndrome of deletion of the short arm of chromosome 4 is described. In addition, this child had renal insufficiency, which is found rarely in association with the 4p(--) syndrome. Previous reports of this syndrome have described only isolated gross structural abnormalites of the urinary tract. In the case discussed here, we present clinical and functional data which indicate that this patient had bilateral renal dysplasia.


A case of ring chromosome.

A case of ring chromosome. A girl with a G22 ring chromosome is described. There are few physical abnormalities, performance quotient is in the low normal range but verbal skills are much retarded.


Familial Ebstein's anomaly.

Familial Ebstein's anomaly. A family is described in which both a father and son are affected with Ebstein's anomaly, while several other family members manifest different cardiac malformations. Five additional instances of familial Ebstein's anomaly were found in the literature and compared with our family. Inspection of possible modes of inheritance in this group of families suggests that Ebstein's anomaly is probably inherited as a polygenic character with a threshold phenomenon.


Partial trisomy D: a diagnostic and cytogenetic dilemma. An 18-month-old proposita with psychomotor retardation and other congenital abnormalities is presented. Chromosomal analysis of both parents proved normal. However, the karyotype of the proposita contained 47 chromosomes in both lymphocytes and cultured fibroblasts. The marker chromosome proved to be a deleted No. 14 or 15. Comparison of the reported cases of partial trisomy D indicates that a definitive clinical syndrome is not apparent in either case.


Larsen syndrome in two generations of an Italian family. This paper describes a familial case of Larsen syndrome. Typical anomalies were present in the propositus and 2 of his 6 daughters. In addition, all patients had progressive deafness and the 2 daughters had cleft palate. The certain exclusion of any consanguinity between the couple, suggests, in this instance, the dominant mode of transmission of the syndrome.


Evolutionary divergence and length of repetitive sequences in sea urchin DNA. The organization of repetitive and single copy DNA sequences in sea urchin DNA has been examined with the single strand specific nuclease S1 from Aspergillus. Conditions and levels of enzyme were established so that single strand DNA was effectively digested while reassociated divergent repetitive duplexes remained enzyme resistant. About 25% of sea urchin DNA reassociates with repetitive kinetics to form S1 resistant duplexes of two distinct size classes derived from long and short repetitive sequences in the sea urchin genome. Fragments 2,000 nucleotides long were reassociated to Cot 20 and subjected to controlled digestion with S1 nuclease. About half of the resistant duplexes (13% of the DNA) are short, with a mode size of about 300 nucleotide pairs. This class exhibits significant sequence divergence, and principally consists of repetitive sequences which were interspersed with single copy sequences. About one-third of the long duplexes (4% of the DNA) are reduced in size after extensive S1 nuclease digestion to about 300 nucleotide pairs. About two-thirds of the long resistant duplexes (8% of the DNA) remains long after extensive SI nuclease digestion. These long reassociated duplexes are precisely base paired. The short duplexes are imprecisely paired with a melting temperature about 9 degrees C below that of precisely paired duplexes of the same length. The relationship between length of repetitive duplex and precision of repetition is confirmed by an independent method and has been observed in the DNA of a number of species over a wide phylogenetic area.


Hemoglobin Vancouver [alpha2beta2(73)(E17) Asp replaced by Tyr]: its structure and function. Hemoglobin Vancouver is a new abnormal hemoglobin with an amino acid substitution of the normal aspartyl residue 73 of the beta chain by a tyrosyl residue. It was discovered in a man of Chinese descent in association with beta thalassemia. It was subsequently detected in a sister in association with normal Hb A. The oxygen affinity of the abnormal hemoglobin is decreased but its subunit interaction is normal. The Bohr effect may be slightly increased. This is the fourth abnormal hemoglobin to be found with a substitution at beta73. The others are Hb C-Harlem (alpha2beta2 6Glu replaced by Val and 73 Asp replaced by Asn), Hb Korle-Bu (alpha2beta2 73Asp replaced by Asn), and Hb Mobile (alpha2beta2 73Asp replaced by Val). Although Hb Mobile was found in the present studies to have a decreased affinity for oxygen, Hbs C-Harlem and Korle-Bu have been reported to be normal. These observations of functional differences for variants of beta73 added to earlier observations of the role of the normal beta73 residue to the aggregation of sickle deoxyhemoglobin indicate that this position of the molecule may be important in intra as well as intermolecular interactions.


Congruency of phylogenies derived from different proteins. A molecular analysis of the phylogenetic position of cracid birds. This communication examines the question of phylogenetic congruency--i.e., whether or not the branching order of evolutionary trees is independent of the protein studied. It was found that trees constructed for birds on the basis of immunological comparison of their transferrins, albumins, and ovalbumins agree approximately with a published tree based on the amino acid sequences of their lysozymes c. This congruency is especially noteworthy with respect to the phylogenetic position of the chachalaca, a Mexican bird classified on morphological grounds in the family Cracidae of the order Galliformes. At the protein level, this species differs as much from non-cracid galliform birds as does the duck, which belongs to another order. Despite the organismal similarity between cracid and non-cracid galliform birds, the molecular relationship is remote. If this contrast between organismal and molecular results had been based on comparative studies with only lysozyme, one could have ascribed the contrast to the possibility that chachalaca lysozyme was paralogous, rather than orthologous, to the other bird lysozymes c. Examination of several proteins is thus desirable in cases of possible paralogy.


Origin of organic compounds on the primitive earth and in meteorites. The role and relative contributions of different forms of energy to the synthesis of amino acids and other organic compounds on the primitive earth, in the parent bodies or carbonaceous chondrites, and in the solar nebula are examined. A single source of energy or a single process would not account for all the organic compounds synthesized in the solar system. Electric discharges appear to produce amino acids more efficiently than other sources of energy and the composition of the synthesized amino acids is qualitatively similar to those found in the Murchison meteorite. Ultraviolet light is also likely to have played a major role in prebiotic synthesis. Although the energy in the sun's spectrum that can be absorbed by the major constituents of the primitive atmosphere is not large, reactive trace components such as H2S and formaldehyde absorb at longer wavelengths where greater amounts of energy are available and produce amino acids by reactions involving hot hydrogen atoms. The thermal reaction of CO + H2 + NH3 on Fischer-Tropsch catalysts generates intermediates that lead to amino acids and other organic compounds that have been found in meteorites. However, this synthesis appears to be less efficient than electric discharges and to require a special set of reaction conditions. It should be emphasized that after the reactive organic intermediates are generated by the above processes, the subsequent reactions which produce the more complete biochemical compounds are low temperature homogenous reactions occurring in an aqueous environment.


A basic study of the Hanssen technique for evaluation of single nephron glomerular filtration rate. The purpose of this study was mainly to examine some basic problems of the Hanssen technique for the evaluation of single nephron glomerular filtration rate (SNGFR). Firstly, experiments were performed using Wistar rats to determine the amount of C14-ferrocyanide necessary to give sufficient C14 radioactivity in dissected nephrons. Using 200 muCi of C14-ferrocyanide, the samples of dissected nephrons provided only twice as much as background. Hence, we chose the amount of 600 to 700 muCi of C14-ferrocyanide for each rat in the later experiments, which yielded the radioactivity 5 to 6 times as much as background. Secondly, the homogeneity of intrarenal C14-ferrocyanide distribution was tested. Five superficial (SUP) and juxtamedullary (JM) proximal tubules four different regions were dissected and the radioactivity of those nephrons was counted. The distribution of C14-ferrocyanide in each piece was representative of the overal distribution. The summary of morphologic and clearance studies were as follows. The mean lengths of proximal tubules of 40 SUP nephrons, 5.3 +/- 0.2 mm, and 39 JM nephrons, 6.3 +/- 0.1 mm, were significantly different (P less than 0.01). The mean glomerular diameter of the JM nephrons, 110 +/- 2.7 mu, was significantly greater than that of the SUP nephrons, 95 +/- 3.1 mu (P less than 0.01). The mean SNGFR of 129 SUP nephrons, 23.4 +/- 4.2 nl/min/100g Body Weight (BW), and that of 130 JM nephrons, 34.5 +/- 5.1 nl/min/100g BW, were significantly different (P less than 0.01). The ratio of superficial/juxtamedullary nephron glomerular filtration rate (S/JM Ratio) was 0.85 +/- 0.02. We conclude that C14-ferrocyanide is regularly distributed to the kidney and that it is necessary to infuse sufficient amount of C14-ferrocyanide in this technique.


The effects of atropine on atrio-ventricular conduction in patients with Wolff-Parkinson-White syndrome. Studies with His bundle electrogram. The effects of atropine on normal and anomalous A-V pathways were investigated using HBE in 40 cases consisting of 25 subjects without pre-excitation (group I) and 15 cases with WPW syndrome (group II). In group I, A-H interval shortened with a mean decrease of 30% following the administration of atropine (p less than 0.001), while P-A and H-V intervals as well as QRS duration remained unchanged. In group II the electrocardiogram showed WPW syndrome pattern (pattern W) in 12, normalization (pattern N) in 1 and both patterns (pattern WN) in 2 cases during the control study. In 10 cases pattern W persisted after atropine. Atropine changed pattern W to WN in 2 cases, WN to W in 1, WN to N in 1 and N to WN in one case. P-d interval remained constant. Atropine had no effect on the conduction time within atrium. His-Purkinje system and anomalous A-V pathway, but accelerated the transmission through A-V node. Atropine decreased the QRS duration of pattern W in 11 of 13 cases showing pattern W or WN both before and after atropine. Since the QRS duration showing pattern W correlated with P-H interval and (see article) and had the negative correlation with H-d interval (p less than 0.001), fusion mechanism was considered as the genesis of electrocardiographic pattern in most cases with WPW syndrome. Atropine influence was negative on QRS complex of pattern W i2 cases showing the co-existence of Kent bundle and James fibers or exclusive Kent bundle conduction. In the latter case the selection of antiarrhythmic agents should be made with caution. A-V dissociation with junctional rhythm developed in 9 cases (4 in group II) within 2 and a half minutes after atropine. The duration was as short as 15 seconds or less in 6 cases. The continuous tracing is necessary not to miss the AV dissociation. The disappearance of delta wave after atropine was observed during the change to pattern WN and the occurrence of A-V junctional rhythm or beat in 5 of 12 cases showing pattern W prior to the drug administration, and right bundle branch block was disclosed in 2 cases. The normalization of QRS complex also made it possible to measure His-Purkinje conduction time. In this point atropine is superior to the other antiarrhythmic agents which prolong H-V interval. Paroxysmal supraventricular tachycardia induced after atropine revealed shorter A-H with fixed H-V and V-A intervals, compared with the tachycardia before atropine in one case. The administration of atropine serves as an aid to evaluate the participation of anomalous A-V pathway in the tachycardia circuit.


Experimental studies of effects of acute renal venous congestion on renal function --with particular reference to renal arterio-venous plasma sodium difference. Effects of acute renal venous congestion on renal function were studies. In anesthetized mongrels with intermittent or sustained elevation of the renal venous pressure produced experimentally by unilateral constriction of the renal vein, changes in renal function were investigated with the clearance method and plasma concentrations of electrolytes, protein and Ht of collected arterial and venous blood oals were divided into two groups according to the initial conditions concerning the various level of renal arterio-venous plasma sodium. In dogs (Group A) whose initial values of renal arterio-venous plasma sodium difference were not less than -1 mEq/L, the difference showed a negative tendency both during intermittent and during continuous congestion. In dogs (Group B) whose initial values of the difference were less than -1 mEq/L, the difference showed a positive tendency during renal venous congestion. (2) In dogs of Group A, i) the sodium reabsorption rate increased when renal physiological values (GFR and RPF) remained unchanged (during intermittent congestion) as well as when these values decreased (during continuous congestion). ii) The calculated "postglomerular" oncotic pressure and the sodium reabsorption rate were strongly correlated at the control period, showing a slightly less correlation during intermittent renal congestion, whereas during sustained congestion, the latter increased independently of the former. iii) The NCPF/CPAH remained unchanged or slightly increased during intermittent congestion and was remarkably elevated during sustained congestion. (3) In dogs of Group B, i) Diminution of renal functions such as GFR and RPF was prominent during renal congestin and satisfactory recovery of renal functions to the initial level did not occur even after release from congestion. ii) No significant increase of sodium reabsorption rate was obtained during continuous renal congestion. (4) The balance of sodium ion between the kidney and blood of dogs of Group A was discussed. The effects of acute renal venous congestion on renal function were divided into two groups and it was concluded that this renal arteriovenous plasma sodium difference is a most significant factor.


Effect of changes in inputs to atrioventricular node on AV conduction. The effect of different inputs into the atrioventricular node (AVN) on orthograde impulse transmission was studied. In rabbit AVN preparations, two stimulating electrodes were placed posteriorly in the crista terminalis (P) and anteriorly in the interatrial septum (A). Electric stimuli were given individually (P,A) or simultaneously (P + A). Premature stimulation, when properly timed (e.g. 70-100 msec at the basic cycle length of 400 msec) achieved AV conduction only in P + A but not in either P or A. Action potentials (APs) in AVN in this situation revealed an incomplete depolarization in P and A, but became a fullsized AP in P + A. This might be explained by summation. The site of simmation appeared to be in the upper node, because APs distal to the middle node as well as APs in the His bundle behaved in an "all or none" fashion. Time intervals between the stimulus artifact and the His bundle AP upstroke (S-H) were shorter in P + A was enhanced with the decrease of the S-H difference between P and A suggested an accelerated conduction by summation in AVN. A hyperpolarizing current flowing through the suction electrodes which were attached in the vicinity of AVN caused different amounts of S-H shortening between P and A input. The above data support the view that AVN has a summating property engendered by the slow inactivation of ionic channel on which the upstroke of AP depends and by the limited number and sites of atrial inputs which might connect with some preferential paths within the AVN.


Automaticity and time-dependent conduction disturbance produced in canine ventricular myocardium. New aspects for initiation of ventricular arrhythmias. 1) In isolated canine ventricular myocardium, automaticity could be induced by a passage of small depolarizing DC-currents. The mechanism was attributed to inflowing Ca++ and Na+ currents and time-dependent deactivation of outward K+ current under a condition of high membrane resistance due to an anomalous rectification. Significance of the automaticity was discussed in relation to the ventricular arrhythmias encountered in very early stage of myocardial infarction. 2) In in situ canine hearts, chloropromazine induced time (preceding cycle length)-dependent decrease in conduction velocity within the ventricle. Thus QRS-duration of non-premature beats was lenghtened at rapid pacing rates while QRS-duration of atrial premature beats was lengthened also at short coupling intervals in the drug-treated dogs. These slow conductions were not due to reduced take-off potential of action potentials bue due to drug-induced slow recovery of rapid Na+ system. The phenomenon may be responsible for reported QRS-prolongation and fatal ventricular arrhythmias encountered in the patients receiving phenothiazines.


Role of slow inward current in the genesis of ventricular arrhythmia. Action potentials of premature beats in ventricular muscle fibers showed a transient prolongation of duration as well as an increase in second depolarization of the plateau phase when the preceding diastolic intervals were progressively shortened. These changes were abolished by manganese ions. Voltage clamp experiments also disclosed a transient increase in slow inward current in premature excitations, of which time course was very similar to that in action potential changes. These results suggested that prolongation of action potential durations was mainly brought about by changes in slow inward current and this was partly related to the characteristics of recovery from inactivation of this current. An increase of slow inward current produced depressed conduction on the subsequent beat and it also shared the effects to extend the areas of slow response. These effects may accelerate the occurrence of re-entry.