Antibiotics in the treatment of wounds in the victims of the earthquake in the Armenian SSR

Purulent wounds in 88 victims of the Armenian earthquake with the syndrome of long-term squeezing were examined microbiologically and the experience with using antimicrobial drugs for their treatment was analyzed. In all the cases microbial associations were detected, coliform and nonfermenting gram-negative bacilli, enterococci, anaerobes and yeast-like fungi being isolated from 80, 20, 15 and 25 per cent of the patients respectively. 130 bacterial strains were studied in detail. 80 to 100 per cent of the bacterial isolates were resistant to the antibiotics routinely used in surgical practice, i.e. benzylpenicillin, tetracycline, levomycetin, kanamycin, cephalothin and cefazolin and highly sensitive to new antimicrobial drugs belonging to ureidopenicillins (mezlocillin), quinolones (ciprofloxacin) and cephalosporins of the 3rd generation (cefoperazone and ceftazidime). Retrospective estimation of the antibiotic therapy revealed its inadequacy in 55.7 per cent of the patients for the most part because of the isolates resistance. The 19 variants of the antibiotic use prescribed by the physicians mainly included penicillins, aminoglycosides and their combinations (in 67.2 per cent of the cases). The use of the highly efficient drugs of the groups of ureidopenicillins and quinolones was extremely rare which was likely due to lacking of information on the drugs.     

Changes in the size of the nucleoli of the Purkinje cells in the canine cerebellum in the postresuscitation period

The changes in the size of Purkinje cell (PC) nucleolus in the lateral and medial cerebellum zones were studied in dogs with different degree of neurologic status recovery after clinical death of various etiology and duration. PC always possess one nucleolus in the control and experimental groups. In the case of complete neurologic status recovery of animals the area of PC nucleolus increases in both zones studied, irrespective of the cause of clinical death. In the case of neurologic disorders the increase in PC nucleolus area is clearly expressed only in the medial zone of the cerebellum, being insignificant in the lateral zone. It is suggested that adaptive characteristics of PC are distinct in the two compared zones, which leads to greater PC vulnerability in the lateral zone during deep hypoxia.     

On the role of the pineal in thermoregulation in the pigeon

Diurnal rhythm in body temperature of pigeons subjected to different experimental conditions (pinealectomized, sham-operated, melatonin-implanted, cold-exposed) was studied under a 12 h light and 12 h dark regimen. The body temperature of pigeons during photophase was higher than that during scotophase in the normal as well as every treatment group studied. Pinealectomized pigeons showed higher body temperature in the photophase as well as scotophase, than that of the normal and sham-operated birds when examined 2 or 3 weeks following the post-surgical acclimatization to 25 or 3 degrees C. However, subcutaneous implantation of melatonin pellets into pinealectomized pigeons nullified or even reversed the hyperthermic effect of pinealectomy. Exposure of pigeons to--18 degrees C for 280 min during photophase as well as scotophase, produced a marked drop in body temperature in pinealectomized, sham-operated and normal pigeons. The pinealectomized pigeons exhibited a higher body temperature than that of the sham-operated and normal ones when exposed to--18 degrees C during the photophase, but not during the scotophase. It was concluded that while the pineal is not necessary for maintaining the daily thermal rhythm in the avian body, it has a thermoregulatory role, in that it prevents rise in body temperature in warm (25 degrees C) acclimatized and chronic cold (3 degrees C) exposed birds. In acute short-term cold (--18 degrees C) exposure however, the temperature regulatory role of the pineal was not effective during the scotophase.     

Histogenesis of the taste buds of the vallate papilla in the in the rat in the postnatal stages of development

The developing taste buds of vallate papillae were studied with electron microscope in rats during the first 7 days after birth. Two types of cells--light and dark--are identified in the taste buds of a one day old animal. The apical parts of dark cells are characterized by numerous dark granules. A distinguishing feature of light cells is the presence of synaptic contacts with afferent intragemmal nerves. On the 4th day of development on the top of the apical parts of the cell, a microvillar apparatus is seen to form, which does not yet communicate with the oral cavity. On the 7th day, basal cells appear in the taste buds. Some of these cells are seen mitotically dividing. The differentiated microvillar apparatus now communicates with oral cavity. The structure of the taste buds is getting similar to that in the adults. The structural and functional peculiarities of the developing taste buds are discussed in association with the period of ontogenesis under consideration.     

Frequency of the stages in the cycle of the seminiferous epithelium in the rat

This study determined the optimum number of tubules to be counted per testis cross section, and the number of animals per treatment group, when changes in stage frequencies in the cycle of the seminiferous epithelium are criteria for assessing effects of treatment on spermatogenesis. A data base of 9,672 observed and staged tubules was collected from testicular cross sections of 15 Sprague-Dawley rats. A significant variation between animals was found for the frequencies of Stages I, II, IV, VI, VIII, and XIII. Computer simulation was used to randomly select different combinations of animal and tubule numbers from the observed data. Stage frequency means from each simulation experiment were compared statistically to observed mean frequencies. A model that used data from all 14 stages was analyzed. The following conclusions were made: a) a minimum of 200 tubule cross sections/testis is recommended for estimating stage frequencies; b) for a fixed number of tubules scored, the number of animals sampled is more important than the number of tubules per animal in reducing variance; c) to detect a difference of 2 standard deviations from the mean with a 2% error rate and examining 200 tubules/testis, at least 12 animals must be used per group when assessing all 14 stages; d) when individual stages are examined using 10 animals per group, only Stage VII has 80% or greater power of test (alpha = 0.05) to detect a frequency difference; e) pooling stages into 3-4 groups is recommended to improve the power of detecting a treatment difference.     

Recapitulation in the development of the components of the counterflow system in the vertebrate metanephros

The investigation has been performed on 107 renal preparations obtained from persons of various age (from 5-month-old fetuses up to 45 years of age), certain representatives of other classes of the Vertebrata are also included: fish, amphibia, reptile and mammalia at various stages of pre- and postnatal periods of ontogenesis by means of preparing graphic and plastic reconstructive models, histological investigation and microdissection. The complexity of the intrarenal branching of derivatives of the mesonephric duct diverticulum, development and structure of the canalicular part in nephrons directly depend on the phylogenetic position of the animal. Complexity of the nephron architectonics occurs along the progressive line of taxonomic groups of higher Vertebrata. The nephron loop becomes longer, thin segment of the nephron canalicular part increases in its length and, at last, in mammalia a cone-shaped fasciculus appears as a structural-functional unit of the osmoregulating apparatus of the constant kidney. In the comparative anatomical and comparative embryological aspects recapitulation is observed concerning certain morphological signs of derivatives of the metanephric duct and nephron.     

2-Hydroxylation of estrogens in the brain participates in the initiation of the preovulatory LH surge in the rat

Estradiol-2-hydroxylase, the enzyme responsible for the conversion of estrogens to catechol estrogens was measured in the brain of female rats at specific stages of the estrus cycle. Radiometric measurements of the enzyme activity in microsomal, mitochondrial, and synaptosomal fractions of the brain revealed a sharp increased in activity at proestrus just prior to the preovulatory LH surge. The enzyme activity declined to lower levels at diestrus and metestrus. No comparable fluctuations were noted in the liver enzyme. These changes in brain enzyme activity in conjunction with demonstrated positive feedback of exogenous catechol estrogens on pituitary LH release, suggest that a rise in endogenous catechol estrogen formation in the brain may be responsible for the physiological induction of the preovulatory LH surge.     

Adrenergic mechanisms in the hepatic microcirculation in the rat

The in vivo hepatic microvascular bed of the rat was observed microscopically in the transilluminated liver and the diameter of the hepatic sinusoids was measured by serial photomicrography. Intraportal infusion of tyramine induced concentration-dependent constriction of the hepatic sinusoids, but also dilatation of the sinusoids when the dose was small. These effects were attributed to the release of endogenous noradrenaline which activated either alpha- or beta-adrenergic receptors and caused constriction, or dilatation, of the sinusoids respectively. Adrenaline and noradrenaline induced similar changes in the hepatic sinusoids as tyramine, while phenoxybenzamine induced dilatation, and propranolol constriction, of the sinusoids. All the above responses were abolished by pretreatment with reserpine. A possible noradrenaline-mediated basal vasomotor tone in the hepatic sinusoids for autonomic control of the blood flow in the sinusoids was postulated.     

Alterations in the incisor development in the Tabby mouse

The X-linked tabby (Ta) syndrome in the mouse is homologous to the hypohidrotic ectodermal dysplasia (HED) in humans. As in humans with HED, Ta mice exhibit hypohidrosis, characteristic defects of hairs and tooth abnormalities. To analyze the effects of Ta mutation on lower incisor development, histology, morphometry and computer-aided 3D reconstructions were combined. We observed that Ta mutation had major consequences for incisor development leading to abnormal tooth size and shape, change in the balance between prospective crown- and root-analog tissues and retarded cytodifferentiations. The decrease in size of Ta incisor was observed at ED13.5 and mainly involved the width of the tooth bud. At ED14.5-15.5, the incisor appeared shorter and narrower in the Ta than in the wild type (WT). Growth alterations affected the diameter to a greater extent than the length of the Ta incisor. From ED14.5, changes in the shape interfered with the medio-lateral asymmetry and alterations in the posterior growth of the cervical loop led to a loss of the labio-lingual asymmetry until ED17.0. Although the enamel organ in Ta incisors was smaller than in the WT, a larger proportion of the dental papilla was covered by preameloblasts-ameloblasts. These changes apparently resulted from reduced development of the lingual part of the enamel organ and might be correlated with a possible heterogeneity in the development of the enamel organ, as demonstrated for upper incisors. Our observations suggest independent development of the labial and lingual parts of the cervical loop. Furthermore, it appeared that the consequences of Ta mutation could not be interpreted only as a delay in tooth development.     

Circadian rhythm in olfactory response in the antennae controlled by the optic lobe in the cockroach

The olfactory response in antennae of the cockroach, Leucophaea maderae, was investigated by measuring electroantennograms (EAGs) in restrained animals. The amplitude of the EAG response to pulses of ethyl acetate, octanol, or fenchone, exhibited a robust, light entrained, circadian rhythm that persisted at least 14 days in constant darkness. Dilution-response curves measured at the peak and trough of the rhythm indicated there was a 10-fold change in sensitivity. The EAG rhythm was abolished by severing the optic tracts, while entrainment was abolished by ablation of the compound eyes. The results indicate that the circadian system modulates olfactory sensitivity in the antennae and that the rhythm is driven by a circadian pacemaker in the optic lobes that is entrained by photoreceptors in the compound eyes.     

Role of the substantia nigra in the behavioural-cardiovascular integration in the cat

Electrical stimulation of the substantia nigra elicited complex patterns of response composed of somatomotor and circulatory changes. Increase in blood pressure associated with acceleration in heart rate was consistently produced by substantia nigra stimulation both in conscious and in anaesthetized cats. The respiration was either accelerated or arrested by the stimulation. Also self-stimulation of the substantia nigra elicited pressor responses. Electrical stimulation of the nucleus of the tractus solitarius paired with self-stimulation of the substantia nigra, produced regular changes in the lever-pressing rate for self-stimulation. It is suggested that the substantia nigra is probably involved in the neural mechanisms coupling the circulatory changes with the somatomotor responses.     

Changes in the lungs in the early period of closed trauma of the thorax in rats

In experiments on rats it has been demonstrated that in the acute period of uninjured parts of the lungs periodic changes of protein, lipid and glucose concentrations developed. In uninjured parts of the lungs one can observe more concentration of lipids and in injured parts-more glucose. The changes of substrates, concentrations in the lungs are due to not only the changes of venous blood excess in the lungs, but are connected with metabolic changes in the cells of the injured and uninjured parts of the lungs. The metabolic changes in the lungs in the acute period of chest trauma influence the creation of such indices of gas exchange as PaCO2 and PACO2.     

Mechanism of strengthening of the contractile activity in the duodenum and in the jejunum in psychogenic stress in rabbits

In experiments on unanaesthetized rabbits myoelectric activity (contractile activity index) of proximal (postpyloric) and distal sites of duodenum, and proximal part of jejunum was studied under stress induced by fastening a rabbit to a table in supine position. In both sites of duodenum, the stress impact induced a short-time decrease of contractile activity which was followed by its increase that exceeded the initial level. In the proximal part ofjejunum, the increase of contractile activity took place only during the second part of stress response. The strengthening of the contractile activity of the proximal part of duodenum was preserved after muscarinic or nicotinic cholinoceptor blockage, and after beta-receptor blockage. It was concluded that the contractile response of the proximal part of duodenum did not result from the contribution of central or local neurogenic mechanism, including excitatory cholinergic one, but was humoral in origin. The strengthening of the contractile activity of the distal part of duodenum and proximal part ofjejunum was abolished by muscarinic cholinoceptor and beta-receptor blockage, and resulted from the action of circulating catecholamines on the excitatory beta-adrenoceptor, localized on the cholinergic neurones of the enteric nervous system.     

Muscarinic receptors in the neostriatum--participation in the operant behavior regulation in dogs

Exposure of the dogs to signals, data collection and processing were accomplished using a special PC software. Bilateral microinjections of the muscarinic receptors agonists (oxotremorine) into the neostriatum enhanced the tonic component of instrumental movements, suppressed the phasic component and increased the postural component's amplitude. These changes were much more obvious in microinjections of the non-selective muscarinic receptor agonist carbachol due, probably, to its effect on both the M1 and M4 muscarinic receptors of the neostriatum efferent neurones.     

Neurosecretion in the distal stump of the sectioned hypothalamic-hypophyseal tract in the toad

Summary After section of the hypothalamic-hypophyseal neurosecretory pathway of the toad accumulation of neurosecretory material both proximally and distally to the plane of section was observed. When, in other animals, a second section close to the neurohypophysis was performed, neurosecretory material was absent in the distal stump resulting from the first section. The pile-up of neurosecretion in the distal stump of the unisectioned tract is attributable to a backward flow from the neurohypophysis to the lesion rather than to local synthesis of neurosecretion.The present investigation was carried out as a consequence of a discussion by the senior author with ProfessorWilliam Etkin, Department of Anatomy, Albert Einstein College of Medicine, New York (USA).     

Self-organization in the determination of the size of the axial structures in the embryogenesis of the clawed toad

Experiments were performed using X. laevis embryos during gastrulation and neurulation (stages 10, 11 1/2, 12 1/2, 13 1/2, 15 and 18). Part of presumptive epidermis and lateral plate mesoderm was removed, and embryos raised until stage 25. The size of axial structures (notochord, somite mesoderm, central nervous system) was determined using serial histological sections and compared with that of control embryos. In experimental embryos, the size of axial structures was decreased. Until a specific stage of development, close correlation was found between the volume of embryonic compartment corresponding to a particular, structure and the volume of presumptive epidermis and lateral plate mesoderm. This stage is individual for each axial organ: middle gastrula (stage 11 1/2) for notochord, late gastrula (stage 12 1/2) for somite mesoderm, and late neurula (stage 18) for central nervous system. This data suggest that differentiation pattern of ecto-mesodermal rudiment is subject to regulation during gastrulation-neurulation, and subdivision of ectoderm and mesoderm into axial and non-axial tissues is a self-organizing process.     

Changes in the prekeratin set and in the intracellular distribution of intermediate filaments during the embryonic development of the liver in the rat

Monoclonals against three individual proteins of the epithelial intermediate filaments, prekeratins (PK40, PK49, PK55), were used for immunofluorescence studies of the cryostat sections of the rat embryonic liver. The dynamics of expression and intracellular distribution of prekeratins reflects that of morphological rearrangement of the liver. The development of the system of liver beams was accompanied by changes in the expression and intracellular distribution of PK49 and PK55 and the development of the system of bile ducts by changes in all three PKs. From day 20-21 of embryogenesis all three PKs are expressed in cholangiocytes, while PK49 and PK55 in hepatocytes only.     

Synaptogenesis in the neural ganglia of the heart in the human embryo

Electron microscopy was used to study synapse development in the cardiac ganglia of human fetuses ranging from 8 to 27 weeks of ovulation time. Staining with ethanolic phosphotungstic acid was used for analysis of synaptic active zones. Specialization of interneuronal links begins with the appearance of electron dense material on plasmalemmas of nerve cells in the places of simple contacts. First synapses with single synaptic vesicles and short osmiophilic zones were found in cardiac ganglia in 8-week-old fetuses. Large granular vesicles and mitochondria vesicles are formed from cisternae of agranular endoplasmic reticulum in the preterminal parts of axons and moved by axoplasmic transport to the osmiophilic zones of future synapses. Axodendritic synapses appeared earlier in the cardiac ganglia than axosomatic ones, the latter were observed from the middle of gestation. Transient neuroglial synapse-like contacts were found in the cardiac ganglia. Staining with phosphotungstic acid made it possible to distinguish the degree of synapse maturation according to active synaptic zones. The peculiarities of synaptic development in cardiac ganglia in comparison with that in the central nervous system may be accounted for by different origins of the neural tube and of neural crest and by the level of their phylogenic development.     

Central chemoreception in the region of the ventral respiratory group in the rat

Nattie, Eugene E., and Aihua Li. Centralchemoreception in the region of the ventral respiratory group in therat. J. Appl. Physiol. 81(5):1987-1995, 1996.We injected acetazolamide (AZ; 5 × 10⁶ M, 1 nl) into theregion of the ventral respiratory group (VRG) of anesthetized paralyzedventilated rats. Control injections (mock cerebrospinal fluid,n = 6, or the inactive AZ analogue 2-acetylamino-1,3,4-thiadiazole-5-sulfon-t-butylamide,n = 6) did not increase the integratedphrenic neurogram [phrenic nerve amplitude (PNA)]. The AZinjections produced a focal region of tissue acidosis with a radius < 300-400 µm and are used as a probe for sites of centralchemosensitivity. Injection location is determined by anatomicanalysis. Of 22 VRG injections of AZ, 14 increased the amplitude of thePNA over 15-90 min; 8 had no effect. In 17 cases, we measuredmedullary tissue pH at the injection center and/or at a distantsite and reaffirmed the size of the acidotic region produced by suchsmall AZ injections. Of injections with pH electrodes within300-400 µm of the injection center, all responders showed anacid pH; three nonresponders showed an acid pH, and one an alkaline pH.In a subgroup of five rats, at VRG sites with known respiratory effectsidentified by prior glutamate injection (10 nl, 100 mM), all subsequentAZ injections produced a PNA response. Simultaneous measurement of PNAand tissue pH responses at the injection center of eight rats did notshow a uniform correlation in time; initially, both changed with asimilar time course, but PNA recovered more quickly. We conclude that1) the region of the VRG containssites of ventilatory chemoreception,2) ineffective AZ injections doproduce a tissue acidosis but at sites with minimal impact onbreathing, and 3) tissuepH does not uniquely represent the chemoreceptor stimulus.