[Effect of sensory stimulation on the lamina V pyramidal neurons of the gyrus cinguli in the rat]. Three groups of Wistar-rats were exposed to permanent noise (80 db) during different periods in their postnatal life: the first group was exposed starting from birth for a period of four weeks, the second one from birth up to nine weeks of age and the third group from the fifth up to the ninth week postnatal. A fourth group (control animals) was reared under normal laboratory conditions. After the experiments the brains were exposed to a modified GOLGI-method. In lamina-V-pyramids of the gyrus cinguli lightmicroscopical results: length, number and distribution of spines on the main apical dendrites and on the apical dendritic branches where evaluated. 1. Permanent noise during the early postnatal development phase of the brain of rats (from birth up to the fourth week of age) causes a statistically significant increase of apical spines. The spines-values are 20% above those of the control animals. 2. Permanent noise from birth up to the ninth week of age or applied only during the later postnatal period (from the fifth week up to the ninth week of age) does not significantly alterate the spines-value. 3. The results are estimated as a consequence of extreme environmental factors causing effects, comparable with an universal stress reaction. Conclusions were discussed in comparison to the results of other authors.


Regeneration of proximal and distal part of hydra body cut in the middle of gastral cavity and treated with dactinomycine. Hydras were cut in the middle of the gastral part of the body. The part with the hypostome is marked as H, and the one with the foot as P. Both parts were treated with actinomycine D in 0,5 mg : 200 ml water solution. H-parts are much more sensitive to the effect of actinomycine than P-parts, and P lives considerably longer. It is supposed that such reaction are the result of specificity of H and P cell composition, and of the growth direction which is characteristic of hydra in general. H-part has a proportionally greater number of differentiated cells and this relatively smaller number of non-differentiated cells is spent in it quicker than in P-part in which they are more numerous. The growth direction has a decisive influence on further life of H- respectively P-part. Namely, H- in growth direction does not have any damaged body regions (hypostome and tentacles are intact) and it lacks the amputated P-part i.e. gastral region with foot: the region which is on the opposite side of growth direction of hydra. H-part has all the characteristic cells of this body region, so after amputation mostly it does not change. Unfavourable effect of citostatic manifests sooner and H-part desintegrates quicker. On the contrary, P-part lacks the hypostome with tentacles, and these are the body parts in the growth direction. Zimogen cells can dedifferentiate and differentiate. The hypostome and tentacles regenerate as far as is allowed by actinomycine.


Mitotic index and cell nuclear volume of zona fasciculata externa in processes of postnatal growth of rat adrenals. Mitotic index and nuclear volume of the zona fasciculata externa have been studied using male and female Wistar rats weighing 20, 50, 100, 250 and 300 g. Adrenal weight of females was greater than of males. Early postnatal growth of adrenals was attained at the expense of intensity of mitotic division. With age mitotic division decreased but cell hypertrophy developed. Cell hypertrophy in females began at an early age and was more marked than in males.


Studies on the structure of animal ribosomes. VIII. Application of a digital image processing method to the enhancement of electron micrographs of small ribosomal subunits. Electron micrographs of negatively stained small subunits of rat liver ribosomes have been processed by computer-assisted accumulation. The resulting micrographs are characterized by a significant noise suppression and enhancement of image details.


[Uptake of (3H)-leucine into the total proteins of various Sommer's sectors of the rat hippocampus in vivo and in vitro]. The incorporation of 4.3-3H-L-leucine into total proteins of different Sommer's sectors of the rat hippocampus was studied. The labelling of the acid-soluble supernatant purified through anion exchanger, the specific activity of the proteins and the relative specific activity of the proteins following intraventricular and intraperitoneal application of 3H leucine were determined in vivo and, on hippocampal slices, in vitro. It has been consistently demonstrated in all experimental models that leucine is incorporated into total proteins of the hippocampal structures to a varying degree, the highest label being observed in the region "CA3". The findings seem to reflect differences in the protein synthesis of the individual hippocampal sectors. However, this conclusion was possible only on the basis of resuls taken as a whole, since each experimental model was afflicted with different methodical drawbacks limiting the interpretation of the results obtained.


[Uptake of acetate by Acinetobacter calcoaceticus]. The uptake of acetate by intact nongrowing cells of Acinetobacter calcoaceticus was studied in dependence on the C-source (acetate, n-alcanes, yeast extract, succinate, L-malate) and the growth phase. Single kinetic parameters of acetate uptake were determined. The best acetate uptake was observed with cells cultivated with acetate as the only C-source. Bacteria in the early growth phase were found to transfer acetate twice as fast as cells of the late logarithmic growth phase. The uptake of acetate can be described by a biphasic saturation kinetics with 2 Km values: the Km value for the first phase being 1.10(-5) M, and for the second one, 1.8 .10(-4) M. The corresponding maximal uptake rates are 8 and 37 mM/min/mg dry weight, respectively. Alpha-ketoglutarate, fumarate, L-malate, and oxalacetate inhibit the initial uptake of acetate. Uranylacetate, inhibitors of the respiratory chain and proton conductors in part completely inhibit the uptake of acetate.


[Interactions between the components of the cytochrome P-450-monoxygenase system from liver microsomes. III. N-demethylase activity of cytochrome P-450 relative to the degree of its integration]. Preceding experiments on the immobilization of the multi-component P-450 (LM) system, in which hte order of the first-immobilized component had been varied, gave evidence that the enzymatic activity depends on the degree of association. The present paper deals with the relationship between the degree of association and the demethylase activity. With rising concentrations of the detergent (Triton N-101) up to 0.2%, ultracentrifugation experiments have shown a steady decrease of the sedimentation coefficient from 20-22 down to 4.5 [S]. The demethylase activity (substrate benzphetamine) of the immobilized P-450 declines on reconstitution with solubilized reductase with raising degree of monomerization: 61% (0.02% Triton N-101) and 23% (0.2% Triton N-101) as compared with untreated fixed P-450 equals 100%. The demethylase activity can be increased by raising the reductase concentration in the test preparation.


[Muscle activity and heart rate during rhythmical work on the hand ergometer. I. Heart rate, bioelectric muscle activity and mechanogram relative to the strength of contraction]. The experiments were carried out on 11 subjects ranging in the age from 23 to 37 years. Heart rate, integrated electrical activity from 4 muscles of the forearm and the hand and mechanical activity were measured simultaneously during rhythmical work using a hand-ergometer. The strength of the dynamic contractions was 20, 40, 60, 80 and 100% of a maximal voluntary contraction. The mean values of the maximal voluntary contraction obtained on male subjects were 57.3 kp and on female subjects 33.2 kp. The results showed that during dynamic contractions mechanical activity was related to the integrated electrical activity and both integrated electrial activity of 3 muscles and heart rate were linearly related to the load. The correlation coefficients for the EMG/EMG relationships of different muscles and for the EMG/heart rate varied between 0.83 and 0.98.


[Spectrum analysis of stabilograms with special reference to changes following whole body vibration]. The location of the body's gravicenter in the horizontal plane was measured by means of a force platform. The 4 male subjects stood upright with eyes closed. Power-density spectra of the frontal and sagittal stabilograms were estimated. Repeated investigations made it possible to assess intraindividual variability and to evaluate significant interindividual differences. The power spectral density was not altered by a controlled sitting posture observed for 30 min. Low-frequency whole-body vibration with an exposure time of 30 min and a permissible level according to the "fatigue decreased proficiency boundary" (International Standard ISO 2631) induced a significant increase of the power spectral density below 0.25 Hz and a decrease above this frequency. The results indicate that the power density spectral analysis of stabilograms is a suitable method for evaluating a biological effect of vibration.


[Interpretation of pulse curves by means of the Walsh analysis]. A method for classification of medical data using the Walsh transformation is demonstrated. The Walsh spectrum was obtained by the algorithm of Andrews-Kane-Pratt. The spectral points were used to declare the signals normal or abnormal. The example described in this paper shows that in the case of pulse wave the classification is successful in 93 percent.


[Pathomorphological reactions and noradrenalin content of the heart after administration of depot angiotensin in trained and untrained rats]. A 14-days' training of rats designed to adapt the animals to the procedure of blood-pressure measurement caused in the myocardium a decrease, in serum an increase in noradrenaline ( NA) content. The latter remained unchanged following 3 days of treatment with 2.5 mg depot angiotensin II (AII) but decreased by more than one-half in the myocardium of untreated animals, and increased in serum. Despite the considerable difference in myocardial NA content and blood-pressure behaviour, both trained and untrained rats showed the same morphological reactions following administration of A II. These myocardial alterations which largely correspond to the so-called epinephrine myocarditis should not therefore be due solely to NA action; rather, the involvement of A II should be considered also.


Effect of quinestrol on plasma lipids in women. The effect of Quinestrol (3-0-cyclopentyl-17alpha-ethinyl-1, 3, 5 (10)-triene-3,17-diol), a long acting estrogenic contraceptive steroid, on plasma lipids has been studied in ten women for three months. It was found to lower plasma free fatty acids, cholesterol and cholesterol esters, but to increase plasma phospholipids and triglycerides. The possible causes of these alterations are discussed.


Relationship between the neuromuscular blocking effect of gentamicin and streptomycin and their concentration in blood. The principle of the analysis of concentration-response relationships is valid in the case if the effective course is defined by a logistic function and the drug distribution is approximated by a two-compartment model. The method of calculation the data to construct the curves describing the dependence of the effect on drug concentration in the central and in peripheral compartments was elaborated. The relations between the concentrations of gentamicin and streptomycin and their peripheral neuromuscular blocking effect were investigated experimentally on cats. The blocking action of both drugs is evident at concentrations higher than the drug serum levels after administration of therapeutic doses, gentamicin being more active.


[Animal experimental studies on the thrombolytic effect of ocrase]. The thrombolytic effect of "ocrase", a protease isolated from Aspergillus ochraceus, was investigated in animal experiments. To prevent general hyperproteolysis a protease dose was used which was was neutralized by the inhibitors in the blood of the animals. Experimentally produced deposition and clotting thrombi in peripheral venous or arterial vessels of mice, rats, dwarf pigs and dogs were lysed by regional and systemic administration, and the therapeutic result was estimated by vital microscopy, rheography or angiography. Coronary thrombosis induced in dwarf pigs was treated semilocally with ocrase, and the therapeutic result was followed by ECG and angiography.


Basal hyperinsulinemia in Wistar-rats rendered obese by a high-fat diet. Basal plasma insulin levels were measured in Wistar-rats rendered obese by feeding a high-fat diet (50% fat, w/w). During the period of rapid weight-gaining ("dynamic phase" of the development of obesity) fat-fed rats show elevated basal insulin levels in the peripheral blood plasma. No further enhancement occurred in the so-called "static phase" of obesity. Changing the feeding schedule at 20 weeks of age, e.g. feeding control diets (3% fat, w/v) for 4 weeks to fatty rats, results in a depression of insulin levels to control values together with a reduction of the body weight. The findings are discussed in relation to the dietary induced alterations of carbohydrate and lipid metabolism of obese rats.


[Relationship of inotropic vagal effects to stretching of the atrium]. Isolated left rabbit atria were tested. Preparations are vagal innervated and driven by a constant frequency. Isovolumetric contractions, volumes of the auricles and intraatrial pressures were recorded. With increasing intraatrial pressure the effectivity of peripheral nerve-ending stimulation decreases. There exists a critical value of atrial area. The vagal effectivity will decrease rapidly, if the atrial surface increases higher than this critical value by stretching the auricles.


Nicotine-like effect of prostaglandin F2alpha on longitudinal smooth muscle of cat jejunum. The effect of hexamethonium (1 x 10(-6) M) chlorpromazine (1 x 10(-6) M) and physostigmine (1 x 10(-7) M) on the spastic effects of PGF2alpha (3 x 10(-7) M), PGE1 (3 x 10(-7) M) acetylcholine (1 x 10(-8) M) and nicotine (1 x 10(-7) M), was studied on isolated longitudinal smooth muscle of cat jejunum. The contractile effects of PGF2alpha and nicotine were found to decrease on an analogous scale as a result of hexamethonium and chlorpromasine administration and to be potentiated by physostigmine. Hexamethonium and chorpromazine do not influence significantly the spastic effects of acetylcholine, physostigmine potentiates them less markedly. Hexamethonium reduces whereas physostigmine and chlorpromazine potentiate the contractile effect of PGE1. Taking into consideration also the results of previous studies (Petkov, Radomirov, 1977), it is assumed that the contractile effect of PGF2chi on the longitudinal muscle of cat jejunum is at least partly mediated through ganglionic stimulation, i.e. the mechanism of the spastic action of PGF2chi on the smooth muscle used has at least partly a nicotine-like character.


On some relationships between gamma-aminobutyric acid (GABA) and the cholinergic mechanisms in pentylenetetrazol convulsions. In experiments on albino mice with pentylenetetrazol convulsions it has been found that GABA, introduced intracerebroventricularly in a dose of 100 microgram/mouse, has a marked anticonvulsive effect. Scopolamine in doses of 1, 10 and 50 mg/kg i. p. does not influence significantly the convulsive-seizure reactions, while spasmolytin inhibits them only in large doses (80 mg/kg weight). The inhibitory effect of GABA does not change significantly on the background of scopolamine, while spasmolytin in a dose of 50 mg/kg (and to a lesser extent 80 mg/kg) antagonizes the inhibitory effect of GABA. Arecoline in doses of 1 and 10 mg/kg inhibits to a certain extent the convulsive-seizure reactions, and in doses of 10 mg/kg it potentiates the effect of GABA. Physostigmine in doses of 0.1 and 0.5 mg/kg has no significant effect, while in a dose of 0.3 mg/kg its effect is inhibitory. On the background of the two higher physostigmine doses, however, the anticonvulsive effect of GABA is markedly decreased. The results show that changes in the functional activity level of the brain cholinergic systems lead to changes in the inhibitory effect of GABA on the convulsive reactivity. The mechanisms of these correlations are complex. However, the results are in support of the view that the balance between the different neurotransmitter systems in the brain and not a separate specifically responsible neurotransmitter system, are of decisive significance for the convulsive excitability and reactivity.


Increase in the intestinal slow-wave frequency below the transection through electrical stimulation. Experiments are carried out on dogs with chronically implanted leading-off electrodes on both sides of the transection at the level of the proximal duodenum. A pair of stimulating electrodes are also implanted below the transection. Electrical stimulation with impulses synchronized with the slow waves generated by the segment proximal to the section (amplitude 3-7 V, delay 0.2 s and duration 0.5 s) as well as with periodic impulses (18-21 cpm, duration 0.2-0.5 s and amplitude 3-10 V) results in shortening of the period T of several slow waves from the distal segment. Subsequently the frequency of the slow waves from this segment approaches that of the proximal segment. The restoration of the slow-wave plateau at the beginning of the small intestine depends both on the amplitude and on the frequency of the stimulating impulses. On the background of antagonists of the cholinergic (atr. sulf. 200 microgram/kg) and of the adrenergic systems (propranolol 2 mg/kg and phentolamine 1 mg/kg), increasing the frequency of the slow waves of the segment which is distal to the section requires an increase in the amplitude of the stimulating impulses. The role of the intrinsic nervous system for the assimilation of the slow-wave rhythm from the distal segment by the proximal one is discussed.


Ultrastructural changes in rat striatum after chronic amphetamine treatment. Rat striatum is examined electronmicroscopically after chronic (90-day) treatment with 5 mg/kg dl-amphetamine injected intraperitoneally. Disorganization of the cytoplasmic organelles is observed in part of the nerve cells as well as disappearance of the dense core vesicles. Axonal terminals have reduced electron density, mitochondria with different degree of disorganization and synaptic vesicles and accumulated in groups. Single smooth and concentrically arranged membranes may be found in some of the boutons. Electron-dense bodies and lipid vacuoles are observed in the cytoplasm of the pericytes. The alterations are considered to be the result of chronic amphetamine treatment.


On the coronary and cardiotonic action of crataemon. Crataemon contains the purified flavonoid mixture of Crataegus monogyna. Flowmetric studies of dog coronary blood flow show that it increases after intravenous application of 2 mg/kg crataemon. This increase is statistically significant and lasts about 30 min, with no significant changes in the heart rate and ECG. In experiments on cats it has been found that only the high crataemon doses have a bradycardic effect. Influence on the blood pressure is insignificant and brief. The minute cardiac volume and the cardiac index increase after all doses tested. The work of the left ventricle is also increased, which is considered to be favourable under conditions of operative shock. The general peripheral resistance is much less inhibited, most active being the highest dose tested.


Visual extrapolation of two converging nonintersecting line segments. Fifty subjects were tested to determine the point of intersection between two converging line segments. The angle between the two nonintersecting line segments was 30 degrees. The orientation of the display as well as the distance between the line segments and the point of their intersection was varied. Two-dimensional normal distributions can be accepted to describe the results - the 50 estimates of the point of intersection for each of the five displays presented. The parameters of these distributions are influenced mainly by two factors characterizing the test line segments: (1) proximity to one of the main axes - vertical and horizontal, and (2) distance to the actual point of intersection. The possible mechanisms that might be involved in the estimation of the point of intersection between two converging line segments are discussed.


Mathematical model of the summated electromyogram based on the probability characteristics of single motor units. A probability model for synthesis of the summated electromyogram (EMG) is elaborated on the basis of previous experimental work describing the probability characteristics of the firing of single motor units (MUs) subjected to different external disturbances (e. g. stretch or unloading) and following different instructions for voluntary activation. The possibility is demonstrated some maxima in the summated EMG to be due not to increases excitability of the alpha-motoneurones but to synchronization of the impulses after application of external disturbance, whereby the probability for appearance of impulse in some time intervals will disturbance, whereby the probability for appearance of impulse in some time intervals will increase. The proposed model is used for qualitative studies as a number of factors influencing the value of the signal recorded upon leading off of summated EMG are not taken into account.


Haemoglobin M Boston in an Iranian family. Haemoglobin MBoston is described in a 19 year old Iranian male, his father and three out of his five brothers and sisters which were cyanotic from the birth. The presence of haemoglobin M was established after starch-gel electrophoresis of the ferricyanide treated haemolysate at pH 7.1 and by spectroscopic examination of the purified abnormal haemoglobin at pH 6.5.


A case of ophthalmomyiasis in man by Oestrus ovis Linneaeus in Tehran (Insecta: Diptera, Oestridae). Five first-stage-larvae were removed by soft and pointed blotting-paper from the left eye  of a woman and they were identified as oestrus ovis. She was infected in Tehran and this is the first true case of ophthalmomyiasis due to sheep nasal bot fly in Iran. Reports indicate that case of ophthalmomyiasis are more frequent in Iranian villages with different degree of severity. Methods for prevention and treatments are also discussed.


Idiopathic splenomegaly in Iran.

Idiopathic splenomegaly in Iran. During the past 5 years we have investigated 45 patients with the clinical manifestations suggestive of cirrhosis. We found 40 of them having cirrhosis but 3 patients had idiopathic splenomegaly. They underwent splenctomy and after 1-5 years they have remained free of the disease.


Prevalence of high blood pressure in Qashqai Tribe, Southern Iran, 1973. On the basis cross sectional health and morbidity survey was conducted in 1973, an attempt was made to measure the prevalence of high blood pressure among Qashqai Tribe. Our study showed that hypertension is by no means a rare condition among nomads and it tends to be a little higher in women than in men age group 35 years and over. Our figures showed that the pattern of increase of prevalence of high blood pressure with the increase of age.


Inpatient bed needs for psychiatric care. Along with other types of hospital inpatient care, acute psychiatric units are subject to state certificate-of-need review under Public Law 93-641. A study of 15 hospitals in Virginia suggests that prevailing techniques for determining inpatient bed needs are not appropriate for psychiatric beds, if indeed they are for other types of care. An alternative technique is offered, not as a substitute for judgment in such matters, but as assistance to it.


Individual problem rating: a proposed scale. A procedure for Individual Problem Rating (IPR) in the evaluation of community mental health and other types of service programs is presented. The instrument is based on client reports of problems, and its uses problem severity and relative importance as criteria for rating. The issues of client self-rating, variation in levels of abstraction among listed problems, interaction between problems, reliability, and valor to IPR's adoption in clinical practice and treatment evaluations.


Community mental health accreditation: a pilot study. The Balanced Services System is the conceptual framework for the newly initiated community mental health accreditation program sponsored by the Joint Commission on Accreditation of Hospitals (JCAH). The program design and performance of CMH systems are reviewed and judged according to a series of evaluation criteria that prescribe the desired operating state for each functional area in the center.


Recruit, screen, and hire: staff selection and the decision-making process. This article focuses on the role of the clinician-manager in staff selection. The duties of the clinician-manager in a mental health center include those tasks described as "recruit, screen, and hire" but little or no guidance on the steps involved in this sequence of events is available. The "how" of hiring is transmitted by word of mouth, by following another's example, or by trial and error. This article examines the component parts of staff selection from the assimilation of procedures, rules, and regulation of the public authority under which a particular mental health center operates, to the compilation of a "short list" of those to be screened and finally the risk taking and decision-making process by the clinician-manager who makes the choice. Some speculation on the emotional impact it has on the clinician-manager is examined. The impact of personal value judgments of the selector are considered. Recommendations are made for the inclusion of training in staff selection by academic programs for mental health administrators.


Introducing accountability in an outpatient mental health clinic: an administrative process evaluation. The administrative evaluation implemented at TRIMS makes explicit the goals and objectives of the clinic and the extent to which they were attained. Prior to the initiation of the evaluation formalized evaluation procedures and measures of accountability were nonexistent, and the monitoring of clinic activities for descriptive management purposes was noticeably absent. The Goal Attainment Scaling method in the administrative evaluation formalizes the organization's informal process of defining goals and objectives. The evaluation strategy emphasizes the explicit statement of objectives and the criteria on which performance would be evaluated. In essence the evaluation was incorportated into the management activities of the clinic, measures of accountability were established and, based on this experience, an administrative evaluation has been established in all ten clinics in the outpatient division.


The consultant as insider and change agent: the problem of boundaries in social systems. A consultant who is an "insider" must be sensitive to ethical and psychological issues in human systems that are of lesser import to "outside" consultants. Organizational boundaries are considered as being created by the norms required for membership in the systems rather than from outside.


Problems of organizational consultation in the Army. Psychiatrists in the U. S. Army have received official sanction as organizational consultants. In common with other bureaucratic organizations, several obstacles impede their full effectiveness in this role. These include communication breakdowns and negative attitudes toward change. These attitudes are divided into four subgroups: Conspiracy of Silence, Fear of Innovation, Cult of Personality, and "Good Old Common Sense." While these obstacles are not inconsiderable, the possibility for effective consultation still exists.


[Median age of mortality as an indicator of economic-social and nutritional status]. Mean age of mortality as an indicator of economic development and nutritional state. After a short discussion of nutritional indicators the mean age of mortality of the population of a country is proposed. This is defined as the age as 50% mortality is observed. It is an indicator for social-economic development. There exists a correlation between the proposed indicator and others used in the evaluation of nutritional conditions.


[Possibilities of Lupinus mutabolis and Lupinus albus in the Andean countries]. Lupinus albus and Lupinus mutabilis may achieve importance among the andean countries in which soy bean can not grow due to ecological reasons. Both lupin varieties are outstanding because of their high protein and oil content. Its alkaloid content limits the lupins usage; however the bitter substances can be eliminated by means of genetic selection or technological processing. Beside the intoxication caused by alkaloids exists the lupinosis, which is caused by a micotoxin. This disease can be observed when animals pasture forages which suffered under a secundary attack of fungus. According to the results obtained up to date other antimetabolic substances present in the legums have no significant importance. The lupin seed flour is adequate for animal consumption, being used for this effect in different countries. Starting next year there exist the prospects of employing Lupinus mutabilis as an oil source in Peru and Lupinus albus as proteic flour in Chile.


[The influence of the quality of proteins in fluoride bone fixation]. 45 rats Wistar, 30 days old, were divided into five groups, receiving different diets: casein, bean and wheat flour. The last two diets were supplemented or not by D-L Methionine and D-L Lysine, respectively. Diets and fluoridated water (25 ppm) were given "ad libitum" for 28 days. After this period of experience, the animals were sacrificed and the mandible and the tibias removed for analyses of fluoride, calcium, phosphorus and ash. The A.A. main conclusions are the following: The fixation of fluorides in bones is significantly increased with the supplement of the limitant factor to dificients diets. In this condition, the mandible shows smaller fixation of fluorides than tibias. The level of calcium, phosphorus and ash shows to be similar in the diferentes groups. This data suggests interaction of the protein quality and the percentual fixation of fluorides, and the necessity of further studies about this problem.


Fusion and hybridization of marsupial and eutherian cells. Heterokaryon formation. Marsupial x eutherian cell hybrids would be very useful for studies of mammalian genetics and cell biology. A critical step in the formation of such hybrids is the fusion of cells to form heterokaryons. We have examined many different combinations of marsupial and eutherian cells for their ability to fuse, and we have found that all combinations yielded heterokaryons, but with different frequencies, depending on the cell types used. Ranked in order of decreasing ability to fuse with eutherian cells, the marsupial cell types were; established lines, primary diploid fibroblasts and lymphocytes. In all fusion experiments there was a marked preference for the formation of homokaryons compared with heterokaryons. It was possible to control the numbers and types of heterokaryons formed by varying the input ratio of parental cells.


The ecology of influenza. Isolation of type 'A' influenza viruses from Australian pelagic birds. Three different type A influenza viruses have been isolated from pelagic birds nesting on islands of the Great Barrier Reef. One of these, isolated in 1972, was of subtype Hav6Nav5. The other two, which are described in this paper, were isolated in 1975 and belonged to subtypes Hav5Nav2 and Hav3Nav6. Of eight isolates of the latter virus, seven were recovered from cloacal swabs and only one from the trachea.


Pharmacokinetics of sulfadimethoxine in cats. Pharmacokinetic parameters which describe distribution and elimination of sulfadimethoxine were determined in cats. Following intravenous administration of a single dose (55 mg/kg), disposition of the drug was described in terms of the biexponential expression: Cp = Ae-alphat + Be-betat. Based on total (free and bound) sulfonamide levels in the plasma, pseudodistribution equilibrium was slowly attained and the half-time of elimination (half-life) was 10.16 h +/- 2.50 (S.D., n = 6). Body clearance, which is the sum of all clearance processes, was 18.8 +/- 4.6 ml kg-1 h-1. Plasma protein binding, measured by equilibrium dialysis at sulfonamide concentration of 50 microgram/ml, was extensive (87.5% +/- 6.3, n =10). Computer-generated curves for an animal representative of the group, based on individual rate constants associated with the two-compartment open model, showed that 12% and 5% of the dose were present in the central and peripheral compartments, respectively, 24 h after administering the drug. A satisfactory dosage regimen might consist of a priming dose (55 mg/kg) and maintenance dosage (27.5 mg/kg at 24 h dosage intervals). Predicted plasma sulfadimethoxine concentrations would oscillate between 125 and 25 microgram/ml during the steady state. Influence of bacterial disease and febrile states on predicted levels remains to be verified experimentally.


[Peripherial ATP-ases in the different components of the central nervous system of Periplaneta americana L. (author's transl)]. A smaller ATP-ase activity in the abdominal nerve cord of the Periplaneta americana L. was observed when compared by peripheral area with ganglia activity of the central nervous system which have more complex physiological functions. There was no significant difference in the enzyme distribution in the pro, meso, metatoraxic, subesophageal ganglia and the sixth abdominal ganglion.


Substance P: its pharmacology and physiological roles. The recent identification and synthesis of the endecapeptide substance P has renewed interest in this naturally occurring compound. The original substance P of Euler and Gaddum was a mixture of biologically active substances, some of which were peptides. The peptide component was responsible for gut-contracting, hypotensive and sialogogic properties attributed to substance P. For almost 40 years following its discovery, substance P resisted isolation and purification. Even the most highly active preparations were heterogeneous and there was a divergence of results from experiments using preparations which were partially purified by different techniques. Nevertheless much of the early work on the distribution and pharmacology of crude substances P has been confirmed using the synthetic endecapeptide and has stimulated research towards the elucidation of a possible functional role for substance P. Most proposed functions have been highly speculative but, at present, evidence is accumulating in support of a physiological role for substance P as a neurotransmitter in sensory pathways.


[Analysis of mercurial pesticides by complexometric potentiography (author's transl)]. This paper describes a potentiographic complexometric technique developed for determining mercury in mercurial pesticides. It is precise, accurate, specific and rapid. It is based on using Titriplex III, U.05M measuring Ipol of mV.


[The potassium metabolism of typical northern Algerian soils. I. Global evaluation of the potassium supply of soils]. In samples from 87 and 39 profiles, respectively, of typical Northern Algerian soils the following parameters were determined of the K content: total K, exchangeable and water soluble K, K saturation degree, and potassium replenishment capacity. The latter was carried out by four methods (N HCl 50 degrees C, HNO3 boiling, 0.05 and 0.2 N NaTPB). The results obtained were used to check the widespread view that Algerian soils are well supplied with K. The following grouping is suggested from the results of the investigation: --soils with high to very high values for all forms of K (50% of the samples), --soils with lower and medium values for exchangeable K, which require K fertilization actually or in the near future if K uptake by crops increases (30 to 35% of the samples), --soils with TPB values indicating a high binding strength of Ki in which a very limited replenishment power can be expected despite partly high or very high values of acid soluble K (more than 25% of the samples). These results indicate that it is necessary to differentiate the assessment of the K content of Algerian soils.


Wool growth factors and the blood level of glutathione in sheep. Starting from the positive correlation between the content of glutathione in the blood and the wool growth the influence was investigated of the genetic construction [local breed with coarse wool (1), Pakistan breed with semi-fine wool (2), and the F1 of female (1) x male (2) animals], of sex, age (6 or 13 months respectively), and of shearing status (shortly before shearing and 4 weeks after shearing). In all genetic constructions the male, older and shorn animals had a significantly higher (alpha less than 0.05) blood level of glutathione. As compared to the initial breed, the glutathione content in the blood of the F1 animals was significantly higher.


Immunoadjuvant activities of synthetic 6-O-acyl-N-acetylmuramyl-L-alanyl-D-isoglutamine with special reference to the effect of its administration with liposomes. Addition of a lauroyl, stearoyl or docosanoyl group to the primary hydroxy group at the C-6 position of N-acetylmuramyl-L-alanyl-D-isoglutamine gave lipophilic derivatives that had definite adjuvancies in induction of delayed-type hypersensitivity and enhancement of antibody production against a test protein antigen, ovalbumin, when administered to guinea pigs as liposomes, that is without mineral oil. When administered as mineral oil-in-water emulsion, including Ribitype emulsions, rather than as water-in-mineral oil emulsions, N-acetylmuramyl-L-alanyl-D-isoglutamine and its 6-O-acyl derivatives showed only weak immunoadjuvancies.


Uterine cancer and estrogen therapy.

Uterine cancer and estrogen therapy. Recent studies concerning the relationship of exogenous estrogens and endometrial cancer have been reviewed, and the objections to their conclusions discussed. Even considering the most serious of these reservations, it is difficult to avoid the tentative conclusion that estrogens are causally linked to endometrial cancer, and that the attributable risk is numerically sizable. Whether the medical costs will be ultimately shown to outweigh the benefits of estrogen replacement therapy will depend largely on whether or not a relationship to breast cancer is shown, and on the magnitude of the effect of estrogens in preventing serious complications of ovarian failure. For the time being, estrogenic treatment of menopausal symptoms should be as brief as possible, should use the lowest dose possible, and should probably be given in cyclic fashion, particularly to women in intact uteruses. Every attempt should be made to give patients a quantitative understanding of both potential risks and benefits before they decide for or against estrogen therapy.


Vascular complications of long-term oestrogen therapy. Long-term low dose oestrogen therapy has a protective effect on bone mineral content in the post-menopausal or castrated female. As yet the only obvious clinical side effect of such therapy has been transient leg muscle cramps. Several biochemical side effects could be observed. Low dose mestranol caused a persistent elevation of factor VII and a dose-dependent increase in both factors VII and X was observed using oestriol hemisuccinate. Such effects are more likely to be dose-related than related to the type of oestrogen prescribed. Effects of oestrogens on lipids, and cholesterol in particular, may be dose-related also. Changes in blood pressure in post-menopausal women are more likely to be related to obesity than to oestrogen treatment which would seem to have a protective effect against weight increase. No marked changes in the mean risk score for ischaemic heart disease could be detected during oestrogen treatment.


[Occurrence of induced vitamin-dependent mutants of Yersinia pestis]. Vitamin-dependent mutants were isolated from Yersinia pestis after the treatment with supermutagens. From 13 mutants obtained 10 appeared to be unstable. The stable vitamin-dependent mutants were revealed with the frequency of 2.5.10(-11) divided by 4.9.10(-11) by the indirect method of selection and 5.10(-7) by the use of Davis's method. The frequency of amino acid and nitrogen base dependent auxotroph isolation was significantly higher than that of the vitamin-dependent mutants.


[Management of epicondylitis humeri radialis through the decompression of the radial nerve]. The pain associated with refractory epicondylitis humeri radialis can be eliminated not only by denervation, i.e. palliatively, but also by decompression of the radial nerve in certain cases. We assume that the latter procedure eliminates an important cause of irritation, particularily by resection of the tendineous origin of the proximal caput of triceps muscle. In this respect we consider the inferior cervical syndrome, present in all cases, to be the primary pathogenetic factor in accordance with REISCHAUER.


[Vascular causes of median and ulnar nerve compression syndromes]. From a group of more than 200 patients with median and ulnar nerve compression syndrome three cases of interest are demonstrated in detail. In these cases vascular complications led to acurate events accompanied by grave symptoms. In order to prevent irreversible damage surgical treatment of such cases is indicated as soon as possible.


[Functional mechanisms of the proximal ulnar nerve compression syndrome]. The proximal ulnar compression syndrome when it is not a result of trauma, tumors, inflammatory and degenerative processes, inborn deformations or external pressure, is caused by two mechansims, namely the pinching of the ulnar nerve between the proximal edge of the ligamentous and muscular coverings of the cubital tunnel and of the exit of the nerve from the tunnel under the tendinous arch of the flexor carpi ulnaris. The compression itself is dependent upon the possibility of subluxation of the ulnar nerve. Therapy should consists not only in "decompression", but also in a simultaneous anterior transposition of the ulnar nerve.


[Therapeutic possibilities in fibro-lipomatous hypertrophy of the hand and finger nerves]. If the main nerves of the forearm and wrist are effected with fibro-lipomatous hypertrophy, decompression can be performed as a palliative measure. As the disease is not pregressive, resection or defatting of the hypertrophic fascicles should be avoided. The fibrous and lipomatous tissue cannot be separated from the fascicles without damaging them, even if the finest microsurgical technique are applied. As the disturbance of motor function increases, reconstructive surgery is necessary. In the fingers the "tumor" can be resected completely; the sensation of functionally important areas should be reconstructed with a neurovascular island flap or local pedicle flaps.


[Anterior interosseous nerve syndrome].

[Anterior interosseous nerve syndrome]. A case of anterior interosseus nerve palsy is reported. The anatomy and the syndrome are described. The clinical investigation and problems of differential diagnosis are discussed. Therapeutic suggestions are given.


[A new intraosseous finger-joint prosthesis]. The faults of interposition-arthroplasty of the finger-joints were shown and intraosseous implantation and intraosseous endoprothesis are presented with initial results. Sources of failure and their treatment are explained and postoperative details and postoperative treatment outlined.


[Results of alloarthroplasty in finger joints damaged through injury]. Follow-up examination is reported of 24 patients with post-traumatic arthritis treated by 29 finger joint implants. The average follow-up time was 35 months. It could be shown that implant arthroplasty in painful, unstable finger joints stiffened in an unfavourable position represents a quite reasonable method of treatment. Necessary essentials, however, are sufficient function of the tendons, skin areas without twoo extensive cicatrical changes, precise operative procedure and adequate postoperative treatment.


[Epilepsy and Dupuytren's contracture--a syntropy of 2 diseases?]. Dupuytren's contracture was observed in 21,6 percent of 524 patients with epilepsy. This combination is characterised by a steadily progression by relatively benign course with a consequenly low frequency of operation and rate of recurrence. Possible genetic association has to be taken into consideration, because idiopathic epilepsy is the type most frequently found with Dupuytren's contracture. In this material no correlation has been found between Dupuytren's contracture and liver disease. Diabetes mellitus and other aetiologic factor which have been suggested. The duration of epilepsy and the medication given have not been analysed.


[Problems of arteriovenous fistulas].

[Problems of arteriovenous fistulas]. Based on a personal case of congenital arteriovenous fistula we discuss the problem of the surgical treatment of this disease. Surgical treatment is always indicated in any case of systemic haemodynamic effects. The surgical treatment is not always successful as the fistula cannot always be exactly located. Another problem is the development of new circuits in regions mo-e proximally situated. This results in a high volume shunt, even if the more peripheral anomalies seem to have been removed completely. It is not sufficient to disconnect and resect the main arteries, without removing the fistula or the angioma, or new collateral vessels and trophic changes will be seen.


[Diseases of the pisiform bone].

[Diseases of the pisiform bone]. Isolated diseases of the os pisiforme is seldom described in the literature. Since 1973 wehave seen 7 patients with typical signs: pain at the region of pisiform, increased by dorsiflexion and radial deviations of the wrist and by compressing the pisiform in the palmar-dorsal plane. The diagnosis of pisiform disease is based on clinical and X-ray examination and followed by histological study after operation. Five of the seven patients came to operation for the following disorder: local, circumscribed chondrosis, chondromatosis of flexor carpi ulnaris with osteochondromatosis, atrophy of the pisiform and in the two cases aseptic osteonecrosis. After partial resection of the pisiform, once combined with Z-shaped lengthening of the tendon of Flexor carpi ulnaris or complete enucleation of the bone all patients were free of discomfort and remained so.


Antagonistic effect of heparin and a water-soluble glucocorticoid on the peripheral lymphocyte count in mice. The effect of heparin and prednisolone succinate on the peripheral white blood cell count of mice has been studied 3 hours after injecting the drugs. Heparin in low doses did not influence the cell count but in higher doses (20 to 400 U) elicited marked lymphocytosis. When prednisolone and heparin were administered together, heparin (5 to 10 U) markedly inhibited the prednisolone-induced lymphopenia. The effect on the lymphocyte count of prednisolone combined with a large dose of heparin depends on the doses of the drugs. The antagonism seems to be non-competitive in nature. The PMN count shows only minor changes and the reaction of eosinophils to heparin is less pronounced. The antagonistic effect was manifest on the spleen weight.


Infusion of physiological saline supplemented with adenine, pyruvate and phosphate. After controlled bleeding 20 ml/kg enriched infusion fluid containing 0.005 mol/1 adenine, 0.1 mol/1 pyruvate, 0.1 mol/1dibasic sodium phosphate and 0.15 mol/1 sodium chloride was given to 14 dogs. Three dogs received after bleeding the same infusion fluid without adenine. One dog received only dextran after blood withdrawal and served as control Before and after bleeding and 1, 4, 24, 48 and 72 hours after infusion the levels of 2,3-DPG, ATP and P50 index were determined. After infusion of enriched fluid with and without adenine the level of 2,3-DPG and the value of P50 index increased. No rise in the ATP level was observed.


H-excess A1 and Aint variants among the Bulgarian population. During the investigation of the subgroups of 45,895 A blood group persons, H-excess A1 and Aint variants were found in 0.359%. These variants were subdivided into three categories provisionally named A1H, A1Hint and AintH according to their most typical isoserological characteristics. The results of genealogical investigation are presented. An attempt was made to explain the existence of these atypical subgroups.


Effect of F-leurosine (formyl-leurosine) on platelet production in mice. F-leurosine (formyl-leurosine) was found to exert a thrombocytopoietic effect in CFLP mice. The effect was most pronounced in a dose of 1.0 mg/kg. The increased activity of the megakaryocyte system was not due to thrombocytopenia. The preparation induced in the bone marrow an increasing megakaryocyte formation (increase of the megakaryocyte index, a shift to the left in the qualitative composition of the giant cells, increase of the 75Se-methionine incorporation). F-leurosine seems to exert its effect through a direct stimulation of the megakaryocyte system, which might be utilized in therapy.


Effect of collagen on thrombin inactivation by antithrombin-III and heparin. Thrombin inactivation by antithrombin-III and heparin has been found to decrease in the presence of collagen, whereas thrombin activity and the rate of thrombin inactivation by antithrombin-III alone are not affected. Albumin, at the same concentration as collagen, does not influence either thrombin activity or thrombin inactivation by antithrombin-III or by antithrombin-III plus heparin.


Fibrinogen metabolism in cyanoti congenital heart disease. The metabolism and in vivo kinetics of fibrinogen labelled with radioactive iodine was studied in children with cyanotic congenital heart disease. The patients had a significantly lowered plasma fibrinogen pool, shortened fibrinogen half-life and increased fractional catabolic rate of fibrinogen compared with healthy children. The average plasma fibrinogen and absolute catabolic rate of fibrinogen did not differ from control values. The shortened fibrinogen half-life together with the correcting effect of anticoagulation with heparin indicated that fibrinogen was consumed by chronic disseminated intravascular coagulation. Inhibition of the fibrinolytic system with epsilon-aminocaproic acid in three cyanotic patients had no influence on the fibrinogen half-life in two of them but resulted in its prolongation in one patient.


Nonsynthetizing multiple myeloma.

Nonsynthetizing multiple myeloma. A case of multiple myeloma with no monoclonal protein synthesis is reported. The patient had hypogammaglobulinemia, bone marrow invasion, osteolytic lesions, and plasma cell tumors. The absence of protein synthesis has been demonstrated in bone marrow culture with tritiated leucine. No evidence of immunoglobulin production was found. Bone marrow or plasma cell tumor biopsy may be the only method of diagnosis in such cases.


Serum levels of IgA, IgM, IgD and IgE in IgG paraproteinaemias. The dependence of serum levels of polyclonal IgA, IgM, IgD and IgE on the amount of IgG paraprotein was studied in a series of 58 IgG paraproteinaemias. A significant correlation was found for IgA (r = -0.4782, p = 0.0007), for IgM (r = -0.3296, p = 0.0237) and for IgD (r = -0.3589, p = 0.0143) in the whole series of IgG paraproteinaemias and in the subgroup of myeloma paraproteinaemias (n = 34) for IgM (r = -0.4276, p = 0.0207) and for IgD (r = -0.4384, p = 0.0196).


Cell-mediated immunity in subjects immunized with HLA antigens. Production of cellular immune reaction in subjects immunized against HLA antigens was studied by the capillary migration inhibition test in vitro and by the skin test in vivo. The majority of the immunized subjects (10 out of 13) developed a cell-mediated immunity to the donor antigens. Production of HLA antibodies was demonstrable in a smaller proportion of the cases. The complementary nature of humoral and cellular responsiveness was borne out by the present observations. The result of the skin test performed simultaneously with the migration inhibition test correlated well with the result in vitro.


The portal venous tree simulating dilated biliary ducts on computed tomography of the liver. Intrahepatic portal veins may be identified on routine computed tomography (CT) of the liver. These venous structures appear as linear and branching, low-density regions in the liver which appear to converge at the porta hepatis. Intrahepatic portal veins may simulate the appearance of dilated intrahepatic bile ducts. Venous structures may be distinguished from dilated bile ducts by their obliteration following intravenous infusion of urographic contrast agents. CT numbers of portal veins tend to be somewhat higher than those of dilated bile ducts, but enough overlap of values exists to make reliance upon these numbers in an individual case suspect.


Computed tomography in the diagnosis, staging, and management of abdominal lymphoma. Computed tomography (CT) was performed in 30 patients with histologically proven lymphoma within 1 week of bipedal lymphangiography to assess the relative sensitivity of each diagnostic modality in defining the location and extent of lymphomatous involvement. In 11 patients, lymphangiography significantly underestimated the volume of the periaortic nodal mass and its cephalad extent. In 13 additional patients, CT defined significant renal hilar, mesenteric, splenic hilar, and splenic pulp extension not visualized by lymphangiography. Sequential CT scans performed in five patients proved an excellent way to follow therapeutic response. CT scans were also performed in 26 patients with nonlymphomatous intraabdominal malignancy within a week of lymphangiography. It was of value in staging patients with carcinoma of the testis but was not overly helpful in patients with carcinoma of the ovary or pancreas.


Computed tomography of intrathoracic omental herniation and other mediastinal fatty masses. Computed tomography (CT) is a useful modality in assessing fatty masses in the mediastinum. A case is presented in which a large mediastinal mass was shown by CT scan to be periesophageal, composed entirely of fat; surgery demonstrated omental herniation without visceral herniation.


Holographic displays for computer assisted tomography. Generalized holographic methods may be used to provide three-dimensional displays from a series of adjacent tomograms. Two such methods are described. In the first method, the tomograms are simultaneously recorded as a single "space-multiplex" hologram, which thus reproduces the N images in proper relation to each other in space. In the second method, a single hologram of the total volume is theoretically synthesized.


An investigation of the slice geometry of the EMI head scanner. The slice geometry of the EMI head scanner is investigated. It is shown that the slice thickness is positionally dependent. The slice is thinner in the central part than on the periphery and also thinner on the tube side than on the detector side. It is also shown that there is a missing region between slices A and B.


Slice geometry in computer assisted tomography. In computer assisted tomography, the slice being imaged is not a uniform slab because (1) the X-rays are not parallel, (2) the source and detector may not have equal dimensions, (3) the source collimator may produce a penumbra region on the detector, and (4) in some machines two slices are scanned simultaneously from a common focal spot. One method of measuring slice thickness, uniformity, and overlap is with a phantom containing an aluminum strip at a 45 degree angle. This provides a direct display, in the viewing plane, of the slice profile. Measurements have been made on seven new tomographic scanners, and photographs and plots of slice geometry are presented. It is suggested that slice thickness be defined as the full width at half maximum sensitivity, but that this measure should not necessarily be used as the desirable increment between scans.


Computer assisted tomography in methotrexate encephalopathy. Five children with acute lymphocytic leukemia (ALL) developed encephalopathy following treatment with intrathecal or intraventricular methotrexate (MTX). In these patients computer assisted tomography was informative by revealing areas of decreased attenuation coefficient located periventricularly and in each centrum semiovale (three cases) and calcifications, mostly in the deep and cortical gray matter (two cases), as well as ventricular dilatation (four cases). Contrast injection used in one of these five patients, as well as in another child (not affected by ALL) with MTX encephalopathy, failed to reveal enhancement.


The sylvian cistern on computed tomography scanning. The sylvian cistern is an important landmark in neuroradiology. It can be directly evaluated with computed tomographic (CT) scanning, especially in patients with some degree of cerebral atrophy or when enlarged by masses or fluid accumulations.


Histographic studies in computed tomography of contrast-enhanced cerebral and orbital tumors. The density distribution inside a pathologic zone before and after contrast enhancement has been studied in the computed tomograms of 88 cases of cerebral and orbital tumors, using histographic analysis. The histograms provided additional diagnostic information, especially for vascular tumors. This method is also useful for experimentation with contrast media.


Computed tomography in metrizamide cisternography--importance of coronal and axial views. Computed tomographic scans were performed in 34 patients following lumbar introduction of metrizamide. Imaging of the cranial spaces was obtained with horizontal and inclined (25 degrees) as well as coronal planes. Mass lesions within and encroaching upon the cisternal spaces were demonstrated, and the ventricular system was shown with varying degrees of opacification. Coronal and semicoronal views facilitated the localization of parasellar and incisural mass lesions.


Coronal head scans by computed tomography with patient in sitting position. Coronal scans of any region of the head as well as of the craniocervical region may be obtained with the patient in sitting position. The Hitachi tomograph is used for this purpose.


Computed tomography of the normal pancreas. The normal anatomy of the pancreas is demonstrated by computed tomography (CT) (EMI) in 50 patients with no known pancreatic disease and in 15 comparable postmortem studies. The problems of optimal demonstration of the pancreas in CT and the possible causes of misinterpretation of the pancreatic axial tomography are considered. The size of the normal pancreas was found to be up to 3.0 cm for the head, 2.5 cm for the neck and body, and 2.0 cm for the tail. In assessing these values, it is important to be sure that adjacent structures such as the portal vein, splenic vein, and duodenum are not included in the measurement, that the measurements are taken on scans of maximum resolution with no movements, and that the measurements are strictly related to the anteroposterior diameter. It is considered that gantry tilt will also distort these figures. The reasons for these statements are presented and discussed.


Tomochemistry of the brain.

Tomochemistry of the brain. Noninvasive tomochemical analysis of normal and pathological brain tissues of seven patients has been performed with the technique of dual energy computed tomography. The variation of the effective atomic numbers observed in this experiment is relatively small, less than 6%, while the variation of the electron density is below 4%. Cerebral pathology involves complex variations of molecular constituents, even in macroscopically apparently simple lesions like edema, tumors, hemorrhage, etc. These molecular variations may have opposing, equalizing, or additive effects on the effective atomic number. Our results, supported by existing in vitro data, suggest that the clinical value of this technique is limited.


Computer assisted tomography in adrenoleukodystrophy. Our findings on computer assisted tomography of the brain in four cases of adrenoleukodystrophy are sufficiently consistent to warrant delineation. Early changes, which may predate obvious clinical findings, are represented by areas of decreased attenuation coefficient in the posterior (parieto-occipital) white matter around the trigonum of each lateral ventricle. Subsequently the temporal, parietal, and frontal lobes are involved, and the extensive areas of decreased attenuation coefficient in the white matter become almost indistinguishable from the conspicuously enlarged ventricles. Only a thin ependymal wall separates the ventricular cavities from the leukomalacia lesions. Contrast medium enhancement at the periphery of the affected regions is an important, although inconsistent, feature.


A comparison of radionuclide scanning and computed tomography in metastatic lesions of the brain. Forty-seven patients with a final diagnosis of brain metastases were studied with both computed tomography (CT) and radionuclide (RN) scanning. Fifty-three percent of these patients also underwent contrast enhanced CT. Radionuclide scanning detected 94% of the cases, while CT without contrast enhancement was positive in 89%. The addition of contrast material to the CT examination increased the total sensitivity of CT to 94% and permitted the detection of two cases that were falsely negative on RN scanning and CT without contrast. With both techniques, lesions in the cerebral hemispheres were detected more readily than infratentorial lesions. Radionuclide scanning was less sensitive than CT without contrast in the detection of multiple metastases. Contrast enhanced CT should be used in all cases of suspected cerebral metastases unless contraindicated.


Contralateral temporal horn widening in unilateral supratentorial mass lesions: a diagnostic sign indicating tentorial herniation. Tentorial herniation secondary to supratentorial mass lesions will cause aqueductal compression and raised intraventricular pressure. Under ordinary circumstances, a raised intraventricular pressure will result in the development of hydrocephalus, but, in the presence of a large supratentorial mass, it is impossible for a generalized hydrocephalus to develop; only those parts of the ventricular system that are somehow shielded from the pressure effect of the mass lesion will be able to dilate. This dilatation will most frequently involve the contralateral temporal horn. Often, the atrium of the ventricle and the occipital horn will also be involved and, occasionally, the entire ventricle on the side opposite the mass will be dilated. The association of a large supratentorial mass with considerable shift of midline structures and computed tomography findings of a dilated contralateral temporal horn should be considered indicative of tentorial herniation, unless there are signs of preexisting atrophy or other preexisting disease processes that could have caused widening of the temporal horn.


Failure of computer assisted tomography to detect experimental acute obstruction of major pulmonary arteries. Large perfusion defects were produced by total balloon occlusion of major branch pulmonary arteries in two baboons and one dog. The position and total occlusion were confirmed by pulmonary angiograms. Computer assisted tomography (CAT) failed to demonstrate any difference in the nonperfused segment of lung either before or after intravenous contrast injection.


A substitute for the water box in the original EMI brain scanner. A modified water box for the EMI brain scanner is described. The modified box permits parts of the body other than the brain to be scanned. The patient setup for brain scans is simplified, and motion artifacts have almost disappeared.


The rubber circle: a technique for analyzing computed tomography scans. The authors describe a technique for automated analysis of lesions demonstrated by computed tomography. A seed circle may be superimposed on a lesion by an operator controlled program. By selecting density limits, the program will then automatically outline a particular area of abnormal density and calculate the statistics of the pixels within that area. The information may be viewed on the computer terminal or recorded on the printer. The system may be superimposed on first generation EMI scanners without additional hardware. The time for obtaining the information roughly approximates that of systems employing manually operated cursors.


Case report: computed tomography of "Page" kidney. The radiologic features and computed tomography (CT) findings in a case of "Page" kidney are described. Initial CT scans revealed a large mass in the left renal bed. A repeat CT study using contrast medium showed the mass to be a centrally enhanced renal tissue with surrounding avascular zone. CT gave the most useful diagnostic information of the radiologic examinations performed.


Case report: diminished density surrounding a meningioma, verified to be an overlying cystic astrocytoma. Meningiomas examined by computed tomography (CT) often show an area of decreased density surrounding the tumor. Various explanations include edema of the adjacent brain, loculated or trapped subarachnoid fluid, widening of the subarachnoid space, tissue necrosis, and demyelination. The present report describes a case in which this zone of diminished density was a large cystic astrocytoma, overlying a subfrontal meningioma.


Case report: abnormal perfusion of iodinated contrast material into the ventricular system in cerebral death. Apparent abnormal perfusion of iodinated contrast material into the ventricular system has been observed by computed tomography in a terminally ill patient with acute hydrocephalus due to cerebellar hematoma.


Computed tomography of intraspinal and paraspinal neoplasms. Computed tomography (CT) has been used in the evaluation of 36 spinal neoplasms. Eleven of the 19 intraspinal and all of the 17 paraspinal tumors showed positive CT images. Computed tomography is of diagnostic value particularly in detecting calcified meningiomas, lipomas, and neurofibromas with bony changes. The size of the paraspinal tumors and the degree of bone destruction can be precisely demonstrated by CT.


Computer assisted myelography in disk disease. Computer assisted myelography (CAM) is a technique to examine the spinal subarachnoid space. Adjacent structures that may impinge on this space, such as the intervertebral disks, as well as structures contained in this space, such as the spinal cord, spinal roots, and vascular formation, may also be appraised by this method. At present, CAM is performed by subarachnoid introduction of water soluble contrast material followed by computed tomography in the axial transverse plane. The authors present their technique and their results with representative cases of intervertebral disk disease.


Time controlled computed tomographic angiography. A technique is described which, by exact timing of injection and computed tomography (CT) scans, allows a high contrast medium concentration in blood (14 mg iodine/ml blood) to be reached for a brief period, sufficient for a fast scan of 5 to 10 sec duration. This scan demonstrates the early perfusion of the vascular bed of the various organs. With serial, fast CT scans of the same section with 30 sec intervals for 3 min, a dynamic investigation of contrast medium distribution in vessels, tissue, and excretory pathways may be obtained. Preliminary experiments indicate the promising usefulness of this type of examination for brain, kidney, pancreas, spleen, liver, and small bowel.


Cranial computed tomography findings in anorexia nervosa. Four patients with anorexia nervosa were studied by cranial computed tomography (CT). Three of the four demonstrated abnormal enlargement of cortical sulci and subarachnoid spaces as compared with an age-matched control group. The relationship of this finding to established neuropathological changes in anorexia nervosa is discussed.


Reversibility of cerebral atrophy in anorexia nervosa and Cushing's syndrome. Two patients, one with malnutrition due to anorexia nervosa and one with Cushing's syndrome, showed evidence of cerebral atrophy by computed tomography (CT) of the brain. Several months after the original diagnosis of cerebral atrophy, follow-up CT studies demonstrated essentially total return to normality. It is postulated that the mechanism responsible for the described atrophic changes may be related to protein loss or fluid retention, or both. Correction of these metabolic abnormalities may be followed, as in the two cases reported here, by reversion of the CT findings to normality.


Computed tomography with fan beam geometry. Data collection for computed tomography (CT), using a fan beam of radiation, is considered in detail. The manner in which the required projection data set is built up as scanning proceeds is demonstrated. It is shown that by offsetting the fan beam detector from its symmetrical position by a fraction of the element spacing, and by making measurements over 360 degrees, the spatial resolution of the detector may be increased by up to a factor of two. Results of simulations relating to an actual CT device under construction are presented.


White-gray matter differentiation in computed tomography. A numerical analysis has been performed on six regions of interest within the brain for a total of 60 patients. Three areas of white matter and three of gray matter were included. A difference of 7.1 +/- 1.3 Hounsfeld units (HU: 1,000 scale) was found between white and gray matter. For eight patients who were under 15 years of age, the difference was 5.1 +/- 0.6 HU. Contrast injection resulted in a general increase of values, with gray matter showing a greater elevation by 0.5 HU. The numerical evaluation of white and gray matter has proven to be useful in the diagnosis of leukoencephalopathy.


Periventricular hypodensity in hydrocephalus: a clinico-radiological and mathematial analysis using computed tomography. The computed tomography (CT) scans carried out in hydrocephalic patients before and after surgical treatment [cerebrospinal fluid (CSF) shunting] were assessed by analysis of the densities. The numerical data were compared to the pictorial record on the display console. The periventricular hypodensity was correlated to the clinical parameters and to the time lapse after surgical treatment. The subependymal hypodensity shows good direct correlation to the transit of CSF from the ventricles to the white matter, and to the clinical status of the patients. The mathematical analysis supplies objective data and comparable indices. It constitutes the starting point for an automatic evaluation of the CT images of the process of transependymal CSF resorption in non-treated and treated hydrocephalus.


Computed tomography of cranial subdural and epidural hematomas: variation of attenuation related to time and clinical events such as rebleeding. Forty-one cases of subdural and nine of epidural hematomas were studied with regard to attenuation and the time between trauma and computed tomography scanning. The attenuation of the hematomas showed a consistent decrease with time during the first 4 weeks. High attenuation of chronic subdural hematomas is explained by a sudden or continuous rebleeding. No correlation was found between the attenuation of the hematoma and the attenuation of venous blood from the same patient.


Computed tomography evaluation of holoprosencephaly in infants and children. The computed tomographic (CT) findings of the spectrum of holoprosencephaly are presented. Five cases are used to demonstrate the subgroups of alobar, semilobar, and lobar holoprosencephaly. Familiarization with the CT findings in holoprosencephaly leads to more accurate and earlier diagnosis.


Computed tomography in intracranial cysticercosis. The computed tomography (CT) scans and other radiographic studies of 23 patients with cerebral cysticercosis were reviewed. Parenchymal calcifications, the most common finding, are somewhat better seen on CT scans than on skull films. Ventricular cysts may be suspected by disproportionate enlargement of the involved ventricle. Cysts in subarachnoid cisterns are best detected by performing both CT and pneumoencephalography. Contrast enhancement was not seen with cisternal or ventricular cysts but may be with parenchymal cysticercus lesions.


Computed tomography of trauma involving brain and facial skull (craniofacial injuries). Among head injuries, frontobasal fractures play an important role due to frequently concomitant intracranial complications. Intracranial hematomas, cerebral contusions, depressed fractures, and intracranial air are readily detected by computed tomography (CT). Traumatization of intraorbital structures often associated with blowout fractures and herniation of cerebral parenchyma into the ethmoidal, frontal, or sphenoidal sinuses are best demonstrated by CT. In assessing soft tissue structures, CT is superior to multidirectional tomography, which tends to be more suitable for fine detail study of bony structures. Furthermore, CT is helpful for diagnosing inflammatory processes due to bacterial invasion not infrequently following traumatic communication between the paranasal sinuses and the cranial cavity. Sequelae of head trauma such as posttraumatic porencephaly are clearly demonstrated by CT.


Computed tomographic patterns of pseudohypertrophic muscular dystrophy: preliminary results. At present, the diagnosis of pseudohypertrophic muscular dystrophy (PHMD) rests on the clinical picture and the pattern of inheritance and is supported by electrodiagnostic, histologic, and histochemical techniques. In this report we describe the observed computed tomography (CT) changes in six patients with PHMD and compare these abnormal CT scans with scans of the same anatomic region in 16 normal individuals. Scans of patients with polymyositis and sarcoid myopathy are shown for comparison. Two CT patterns, frequently observed in our series, are described.


A quantitative theory of the Hounsfield unit and its application to dual energy scanning. A standard definition is proposed for the Hounsfield number. Any number in computed tomography can be converted to the Hounsfield scale after performing a simple calibration using air and water. The energy dependence of the Hounsfield number, H, is given by the expression H = (Hc + Hp Q)/(1 + Q), where Hc and Hp are the Compton and photoelectric coefficients of the material being measured, expressed in Hounsfield units, and Q is the "quality factor" of the scanner. Q can be measured by performing a scan of a single calibrating material, such as a potassium iodine solution. By applying this analysis to dual energy scans, the Compton and photoelectric coefficients of an unknown substance may easily be obtained. This can lead to a limited degree of chemical identification.


Proposed system for ultrafast computed tomography. Construction of a new ultrafast scanner system suitable for dynamic computed tomography is now under consideration, with development soon to begin. This system will be characterized by an electronically controlled X-ray generator with wide angle double diffraction, which will permit transverse axial images to be taken in times as short as 0.01 second.


Scleral calcifications in hyperparathyroidism: demonstration by computed tomography. Scleral calcifications were demonstrated roentgenographically in two patients with known hyperparathyroidism and clinically normal eyes. In one of these patients, scleral calcification was evident both on plain films and with computed tomography (CT). In the second patient, a solitary plaque of calcified sclera was visible only by CT. Histopathologic examination of the eyes of a third hyperparathyroid patient who died during surgery demonstrated calcium plaques in the posterior sclera consistent with the CT appearance of the sclera in the other patients.


Coronal computed tomography in orbital disease. Coronal computed tomography (CT) was applied to the diagnosis of orbital disease. With this technique, the size and extent of intraorbital tumors and their relationship to the eyeball, optic nerve, and extraocular muscles were demonstrated, often with information additional to that obtained by the standard axial transverse tomograms. In particular, inferior or superior displacement of the eyeball was clearly revealed. Coronal sections afforded easier comparison with other neuroradiologic examinations. In the evaluation of hyperthyroidism, the extraocular muscles were shown clearly in cross section and enlargement of the muscles was advantageously assessed by this technique. Coronal CT provides additional and complementary information to the conventional axial transverse tomography.


Sagittal computed tomography of the orbit. We report on our preliminary experience with sagittal computed tomography of the orbit. We have found this technique to be useful in the evaluation of the orbit and orbital contents.


Case report: chronic graphite granulomatous abscess simulating a brain tumor. Brain abscess can develop at the site of retained intracranial foreign bodies many years after the injury. This report describes a 6 1/2-year-old child who presented with recurrent severe headaches and a focal seizure of the right upper extremity. Skull X-ray was normal. Computed tomography of the head showed a mass in the left temporoparietal region with a central area of high density and contrast enhancement, thought to be a neoplasm. The mass was seen on the radionuclide brain scan and was avascular on angiography. Craniotomy revealed a foreign body granuloma with a small abscess cavity and a retained piece of pencil graphite. No one in the family could recall if the child had had such an injury.


Case report. Tandem lesions: chromophobe adenoma and meningioma. A number of cases of multiple primary intracranial neoplasms have been reported, including tumors of neuroepithelial and mesenchymal origin. The presence of meniogioma has been reported in association with glioblastoma, oligodendroglioma, astrocytoma, and eosinophilic adenoma. This case represents a unique example of adjacent chromophobe adenoma and meningioma. The usefulness of computed tomography in the diagnosis of concomitant lesions with different density attenuations is discussed.


Labeling of EMI computed tomograms.

Labeling of EMI computed tomograms. The importance of clear and complete annotation of computed tomograms is emphasized. The presence of an "L" on the right side of EMI brain scans displayed with the newer viewer equipment indicates the need for attention to this problem.


[Simulation of the electrical activity of an excitable membrane with an electronic analog (author's transl)]. 1. The sodium and potassium conductances of the HODGKIN-HUXLEY model are simulated by a field effect transistor with a series resistor. This arrangement leads to a simple analog model of the excitable membrane (fig. 1 and 2). 2. Normally, the model is silent (fig. 3), but it becomes automatic (fig. 4) when the decay time (de-activation) of the potassium conductance is at least twice the recovery from inactivation time of the sodium conductance (taud greater than 2 tauri). 3. The effects of changes in sodium (fig. 5 and 6) and potassium (fig. 7, 8 and 9) concentration gradients upon the membrane potential and the ionic currents are easily studied when the model is silent or automatic. 4. When automatic, an increase in the potassium concentration gradient induces a lengthening of the period and ultimately, when the gradient is very high, spontaneous activity is blocked (fig. 9). On the other hand, increases of sodium gradient over 30% of normal value do not modify the period (fig 6). 5. The potassium concentration gradient modifies the excitability solely through membrane polarization (fig. 8), while sodium concentration has no effect on it (fig. 5). 6. Results with the model strengthen the hypothesis that tetraethylammonium (TEA) acts on both the maximum potassium conductance (gK) and the mechanism of sodium conductance inactivation (Tauh) to lengthen the action potential as observed on the Ranvier node (fig. 10). Effects of TEA on potassium conductance activation are also discussed. 7. Because of its simplicity and accuracy, this model lends itself easily to many other simulations.


[Electrical activity of the brain of the eel (Anguilla anguilla L.) subjected to hypoxia and hypercapnia]. The effects of hypoxia and hypercapnia on the electric activity of cerebral vesicles have been studied in 48 unrestrained eels placed in water in a soundproof location. 1. Hypoxia (PwO2 less than 5 torr) was well endured for 8 hours after which sharp bursts appeared, rapidly followed by cerebral death. 2. Hypercapnia (PwCO2 congruent to 14 torr) gave an amplitude decrease in cerebral activity beginning with the first hour, and after 8 hours there was an appearance of slow waves which progressively invaded the recording while the latency of average VER increased. 3. The large resistance of eels to hypoxia, is discussed in relation to the importance of anaerobic glycolysis in fish. The effects of hypercapnia on cerebral electric activity in eels are comparable to those observed in mammals and may be due to metabolic and electrolytic modification in CRL and in nervous cells.


[Effect of dopamine, histamine and acetylcholine on the distribution of cardiac output in the anesthetized rat (author's transl)]. 1. The distribution of cardiac output has been studied in rats, using 15 micrometer radioactive microspheres, before and during an I. V. infusion of dopamine, histamine and acetylcholine (3 microgram/kg/min for 3 min). 2. Dopamine decreased the fraction of cardiac output in the spleen (-26%), colon (-23%) and portal vein (-16%) but did not change significantly the flow fraction delivered to the kidneys. 3. Histamine increased the fraction of cardiac output in the stomach (+66%), pancreas (+42%), small intestine (+15%) and decreased it in the colon (-22%) and kidneys (-12%. 4. Acetylcholine reduced the fraction of cardiac output in the colon (-45%), small intestine and spleen (-24%) and increased it in the liver (hepatic artery, +62%). 5. The fractions of microspheres trapped in the lungs were enhanced by histamine (+69%) and acetylcholine (+111%), probably due to an increase in the fraction of cardiac output passing through the peripheral arteriovenous anastomoses.


Regional properties of dorsal and ventral hippocampus in suppression of intralaminar thalamic unit responses. In chloralose-anaesthetized, Flaxedil-paralysed cats, the suppression of extra-lemniscal thalamic units by dorsal and ventral hippocampus was investigated. Unitary responses to test somatic stimuli, recorded in centrolateral and neighbouring thalamic nuclei, were interacted with conditioning electric stimulation in different regions around the hippocampal arch, including parahippocampal gyrus (entorhinal and retrosplenial areas). Stimulation of dorsal (dhc) and ventral (VHC) hippocampus suppressed roughly equal proportions of responses. However, within each of DHC and VHC, effectiveness depended on the region stimulated. In DHC, fields CA1 and CA3, subiculum (SUB), and retrosplenial area, but not field CA4 or dentate gyrus, usually suppressed extralemniscal units at currents below 1.0 mA. In VHC, the most effective regions were entorhinal cortex, CA3, and CA4 with dentate gryus (FD), while stimulation of CA1 or subiculum was almost ineffective, at currents below 1.0 mA. In VHC, the regions were ranked for effectiveness: Entorhinal cortex=CA3 is greater than FD is greater than SUB is greater than CA1. No topographic relationship was found between hippocampal region and thalamic loci for unit suppression. Lemniscal-type unit responses in ventrobasal thalamus were unaffected by stimulation of the hippocampus or parahippocampal gryus. Interruption of the fornix-fimbria system prevented suppression elicited from CA1 of DHC, or from CA3 but not FD of VHC. It had no effect on suppression elicited from retrosplenial or entorhinal cortex. Hippocampal regional variation of effectiveness in suppressing extralemniscal pathways may contribute to the differential behavioural involvements reported for different hippocampal structures.


The effect of acetylcholine and dopamine on the caudate spindle in cats. Electrocortical activity was reacorded in cats whose caudate nuclei were perfused and electrically stimulated using a push-pull cannula. Electric stimulation invariably induced spindles (10-14 Hz) in the ipsilateral frontal cortex. Perfusions of acetylcholine together with physostigmine reduced the number of spontaneous spindles, the response to electric stimulation and induced behavioural arousal. This effect was atropine-sensitive. Perfusions of dopamine with or without tranylcypromine had no significant effect on the number of spontaneous spindles or the response to electric stimulation. Injections of both acetylcholine and dopamine into the cuadate nucleus invariably induced spontaneous spindles and slow waves. The significance of acetylcholine and dopamine in the caudate nucleus intiating caudate spindles and their significance in controlling arousal is discussed.


Nuclear, nucleolar repair, or turnover of DNA in adult rat brain. Labeled thymidine administered to adult rats is incorporated at a low level into brain DNA as shown by biochemical and autoradiographic methods. This incorporation takes place in part into neuronal nuclei and nucleoli and also into glial nuclei. While incorporation into glial nuclei is interpreted to represent known glial cell proliferation, incorporation into neuronal nucleoli may be related to nucleolar DNA synthesis, which in turn is responsible for the regulation of nucleolar RNA synthesis. It could also be due to DNA repair synthesis. Assuming this latter phenomenon, our results suggest that nucleolar DNA is more sensitive than chromosomal DNA to ionizing radiations and other factors.


Binding of apomorphine to neural membranes. The intrinsic fluorescence of apomorphine has been used to measure its binding to neural membranes. A large number of relatively weak binding sites are concentrated in myelin and synaptic membrane fractions. Butyrophenones have the highest affinities for these sites--KD = 43 micrometer for haloperidol--while dopamine and dopamine releasers and reuptake blockers, as well as a variety of other alkaloids, have much lower affinities. The sites are hydrophobic and undergo a phase transition to a highly fluid state near 26 degrees C. Calcium is a noncompetitive inhibitor of apomorphine binding. Some of the actions of neuroleptic drugs may result from binding to these hydrophobic membrane sites in vivo, blocking conduction in small catecholamine axons.


Sodium exchange between blood, brain, and CSF in normal and hydrocephalic cats. The exchange of sodium between blood, brain, and cerebrospinal fluid was studied in normal and kaolin-induced hydrocephalic cats. The ventricles were perfused to measure fluid formation and Na+ exchange rates. 22Na was added to the perfusion fluid or injected intravenously as a tracer for Na+ movement. Na+ and 22Na were also measured in cortical gray and white matter. Na+ relative specific activities were calculated for brain, effluent fluid, and serum. With 22Na in the perfusion fluid, Na+ exchange was not different from nascent Na+ influx for both normal and hydrocephalic cats. Na+ relative specific activities of cortical gray and white matter were 10 times greater in hydrocephalic than in normal cats. This difference in Na+ relative specific activity for brain may be due to a higher diffusion constant or to a lower brain capillary permeability. When 22Na was given intravenously, the Na+ diffusional exchange for normal cats was less than that measured when 22Na+ was in the perfusion fluid. In hydrocephalic cats, the Na+ diffusional exchange was effectively zero. Na+ relative specific activities of cortical gray and white matter were the same for normal and hydrocephalic cats. These findings suggest that the impaired Na+ diffusional exchange may be due to pathological changes in the choroid plexus.


Transplantation immunity in the brain.

Transplantation immunity in the brain. The resistance of animals to allogeneic tumor cells injected into the brain increases with age. The second-set reaction in the brain of rats appears to be equally effective after preimmunization into the brain and preimmunization into the leg. Also, the presence of cytotoxic antibodies is demonstrable after preimmunization into the brain. These findings suggest that both arcs of the transplantation reaction, the afferent and efferent, are involved in tumor-cell allotransplantation in the brain.


Effects of strychnine, bicuculline, and picrotoxin on inhibition of hypoglossal motoneurons. Postsynaptic potentials, evoked by lingual or hypoglossal nerve stimulation, were recorded from hypoglossal motoneurons of the cat with glass microelectrodes. Lingual nerve-evoked inhibitory postsynaptic potentials (LIPSPs) were recorded in 98% of hypoglossal motoneurons. Hypoglossal nerve stimulation caused a hyperpolarizing potential following the antidromic spike in all hypoglossal motoneurons tested. This potential was unaffected by depolarizing or hyperpolarizing currents, could not be evoked at a stimulus strength less than that which was threshold for the antidromic action potential, and did not change in shape or amplitude at stimulus strengths which were above threshold for antidromic invasion. This hyperpolarizing potential was therefore considered to be an afterhyperpolarization. However, hypoglossal nerve-induced inhibitory postsynaptic potentials were recorded from hypoglossal units which had characteristics of interneurons, thus suggesting the presence of afferent fibers in the hypoglossal nerve. The hypoglossal nerve-induced afterhyperpolarization was not affected by strychnine, bicuculline, or picrotoxin. The LIPSP was antagonized by strychnine but unaffected by bicuculline or picrotoxin. The results suggest that inhibition of hypoglossal motoneurons via the lingual nerve is more likely to be mediated by glycine than gamma-aminobutyric acid (GABA) and is therefore similar to the strychnine-sensitive postsynaptic inhibition of spinal motoneurons.


Spatial propagation of associations in a cortex-like neural network model. A neural network model is studied, having associative memory properties and allowing retrieved associations to propagate within the network. It is intended as a tentative description of the cerebral cortex consisting of "pyramidal cells" with modifiable synapses and "stellate cells" providing feedback through excitatory and inhibitory recurrent pathways. The model is based on some general assumptions: Learning occurs through facilitation of synapses which depends on simultaneous pre- and postsynaptic activity (two-conditional facilitation). Connections within the network are realizations of a random process, implying that nearby cells are more likely to be connected than distant one. The two-conditional facilitation makes it possible for an output signal pattern which occurred in conjunction with a certain input pattern to be retrieved later by reapplying the particular input, the model working as an associative memory. The random connections and the operation of the stellate cell models as linear threshold units give rise to pattern separation in the feedback link. This, in addition to the fact that patterns form associations with themselves, is of importance during the associative recall enabling the network to attain alternative stable modes of activity each corresponding to a learned association. It is shown that a learned pattern of activity which is retrieved, ie, a stable mode, can propagate across the surface of the network. The mode of activity evoked through a certain association may get into contact with modes originating from different associations, forming a stable or slowly moving boundary between the interacting modes. The model is discussed in relation to some properties of the visual system.


[Metabolism of m-xylene in rats after administration of chlorinated hydrocarbons (author's transl)]. Male albino rats of the Donryu strain were divided into 4 groups: the normal control group, tetrachloromethane (CCl4, TCM) group, tetrachloroethylene (CCl2 = CCl2, PCE) group and trichloroethylene (CHCl = CCl2, TCE) group. Each group was consisted of 6 animals. TCM, PCE and TCE were administered orally at a dosage of 13 mmoles/kg as a 50% v/v olive oil solution to rats 24 hours prior to an oral administration of m-xylene (8.2 mmoles/kg as a 50% v/v olive oil solution). The normal control group was administered only olive oil (2.5 ml/kg) 24 hours prior to m-xylene dose. Urine was collected 24, 48, 72 and 96 hours after administration of m-xylene. The urine was analysed for m-methylhippuric acid (m-MHA) by the paper chromatographic method of Ogata et al. The results obtained were as follows: 1) Total urinary excretion of m-MHA in the normal control group was equivalent on a molar basis to about 58% of m-xylene received, and the major portions of the metabolites were excreted on the 1st day. 2) In TCM group, total urinary excretion of m-MHA was about a half of that in the normal control group. It was equivalent on a molar basis to about 30% of m-xylene received (p less than 0.01), and the urinary excretion of m-MHA on the 1st day was significantly less than those of the normal control group (p less than 0.001) and TCE group (p less than 0.05). 3) In PCE group, urinary excretion of m-MHA on the 1st day was significantly less than that of the normal control group (p less than 0.01) and the excretion was delayed. 4) In TCE group, total urinary excretion of m-MHA was slightly but not significantly less than that of the normal control group (p less than 0.05). 5) In TCM-ip group of rats which were given TCM orally 24 hours prior to the administration of m-xylene by intraperitoneal injection, urinary excretion of m-MHA on the 1st day and in 4 days after administration of m-xylene was less than that of the control-ip group.


Imitation of live and televised models by children one to three years of age. The results of these studies indicated that children younger than 1 year possess the cognitive capability of translating a perception of a novel action into their own behavior. However, the likelihood of imitation varied as a function of the nature of the target behavior. For example, actions requiring direct social commerce with the examiner were imitated less frequently than simple motor behaviors with objects, and reproducing gestures was more common than vocalizations. Moreover, imitation seemed to depend upon the child's level of mental development--the imitation of coordinated sequences, which requires the child to associate two external events, lagged behind the imitation of single-unit behaviors. There was no evidence for individual traits of general imitativeness, at least not until symbolic relations were involved. Live models were imitated more than TV models but only prior to age 3. While children under 2 years of age were not facile at imitating sequences of behaviors or delaying performance at short time after modeling, older toddlers readily and accurately imitated televised sequences even after a 24-hour delay. Whereas socially extroverted and fearless children imitated live models more than shy children, TV imitation was not related to temperament, home TV viewing habits, or parental education. Finally, the experience of being imitated may facilitate the social cognition of influencing another person.


[Segmentation and phonetic classification by the DAWID system (author's transl)]. The DAWID speech recognition system, which is briefly described in this paper, performs an acoustical analysis which in some respect can be compared with a phonetic transcription. The limitations of this comparison are discussed. The segmentation and phonetic classification performance of the system is investigated on the basis of 5,520 spoken words (46 different one- and two-syllable words, 12 male speakers). The system performance is examined with the aid of varying classes of speech sounds embedded in different phonetic context. The results indicate that the DAWID system reliably transforms some classes of speech sounds into sequences of symbols, the elements of which represent 'quasi-allophonic' sound classes.


[Carbohydrates of the venoms of Bothrops asper of Costa Rica. Quantitative study]. The venom of the Central American Bothrops asper, previously classified as B. atrox, is very rich in carbohydrates, both in the free state and forming a part of glycoproteins. It also contains neutral sugars (hexoses), methylpentoses, hexosamines and sialic acid. There is a significant difference in the quantity of carbohydrates in the venom of B. asper as compared to that of the South American B. atrox, thus further documenting the different taxonomic position of these two species.


Hematophagous insects as vectors for frog trypanosomes. Experimental infections of three hematophagous arthropods (Rhodnius prolixus, Aedes aegypti, and Culex pipiens) with a trypanosome of the Trypanosoma rotatorium complex found in the frogs Hyla crepitans and Leptodactylus insularum revealed that A. aegypti is a good host for the flagellate; the course of development in the intestinal tract of the mosquito is described from 15 minutes to 168 hours. C. pipiens showed only low intestinal infections and R. prolixus did not permit development of the parasite. It is postulated that, in addition to the transmission of T. rotatorium by leeches, batrachophilic mosquitoes may transmit the parasite to frogs of more terrestrial habits by being ingested by these anurans.


[Infection of wild rats with Angiostrongylus costaricensis by intraperitoneal subcutaneous route]. Three groups of cotton rats (Sigmodon hispidus) were infected with Angiostrongylus costaricensis; the first was inoculated by stomach tube; the second intraperitoneally and the third subcutaneously. In all the groups each rat received 50 L3. The highest rates of infection (51.5%) were obtained by the intraperitoneal route, followed by oral inoculation (47.1%). Poor results were observed (10.5%) subcutaneously.