A sharp increase in the density of pulmonary and pericardial mast cells under monocrotaline-induced pulmonary hypertension in rats

Multifunctional granular mast cells (MCs) are involved in various pathological processes. The response of MC populations of myocardium, pericardium and lung to pulmonary hypertension (PH) has been studies 8 weeks after injection of monocrotaline. Five intact and five experimental rats were used. The density of MCs of different maturity was estimated on paraffin sections stained with Alcian blue and Safranin. Expressiveness of PH was estimated by functional parameters with the help of echocardiograms and by morphological markers. The MC density in myocardium of the intact and experimental rats was relatively low: 2 to 4 cells/mm2. MC density in the pericardium of intact rats was 14 times higher than in myocardium and increased 3 times for PH. The mature Safranin-positive cells predominated (70-80%) in myocardium and pericardium of intact and experimental rats. The MC density in the lungs of intact rats was about 30 cells/mm2; 98% of these cells were immature Alcian-positive cells. The mean density of MCs in the lungs of rats with PH increased 5.6 times. The mature Safranin-positive cells appeared in the lungs of rats with severe pathology. The greatest number of MCs in lungs was in the rats with the most pronounced disorders of myocardium function and marked histological damages (injuries) of myocardium and lungs. The finding show active response of MC population to monocrotaline-induced PH that stimulates migration of immature MCs into pericardium and lungs from the outside. Our data indicate the important role of MCs in the pathogenesis of PH.     

Influence of chemical analogues of microbial autoregulators on the sensitivity of DNA to UV radiation

We established that chemical analogues of alkylhydroxybenzenes (AHB), belonging to alkylresorcinols and functioning as microbial autoregulatory d1 factors, enhance the UV resistance of various DNA molecules of different origin and conformation. These include the linear DNA of the lambda phage, bovine spleen DNA, and the DNA of the pUC19 plasmid that is composed of a number of annular (supercoiled and relaxed) and linearized molecules. Irradiating DNA with UV light (lambda = 254 nm) in the presence of methylresorcinol (MR) or hexylresorcinol (HR) results in comparatively insignificant DNA destruction as evidenced by our data on the electrophoretic mobility pattern in agarose gel. Using the linear Hind III restricts of the lambda phage DNA, we revealed that the protective effect of AHB varies depending on their chemical structure (it is more manifest with HR than MR) and concentration. Importantly, the effect of HR on bovine spleen DNA was based on its protective activity and manifested itself after a long incubation period. Studies using the pUC19 plasmid demonstrated that AHB, apart from increasing the resistance of linearized DNA molecules to UV irradiation, prevented both the supercoiled annular-supercoiled relaxed and the supercoiled relaxed-linearized transitions. The possible mechanisms of the UV-protective effect of AHB on DNA and their contributions to the resistance of dormant microbial forms to environmental factors are discussed.     

Influence of chemical analogues of microbial autoregulators on the sensitivity of DNA to UV radiation

We established that chemical analogues of alkylhydroxybenzenes (AHB), belonging to alkylresorcinols and functioning as microbial autoregulatory d₁ factors, enhance the UV resistance of various DNA molecules of different origin and conformation. These include the linear DNA of the λ phage, bovine spleen DNA, and the DNA of the pUC19 plasmid that is composed of a number of annular (supercoiled and relaxed) and linearized molecules. Irradiating DNA with UV light (λ = 254 nm) in the presence of methylresorcinol (MR) or hexylresorcinol (HR) results in comparatively insignificant DNA destruction as evidenced by our data on the electrophoretic mobility pattern in agarose gel. Using the linear HindIII restricts of the λ phage DNA, we revealed that the protective effect of AHB varies depending on their chemical structure (it is more manifest with HR than MR) and the concentration. Importantly, the effect of HR on bovine spleen DNA was based on its protective activity and manifested itself after a long incubation period. Studies using the pUC19 plasmid demonstrated that AHB, apart from increasing the resistance of linearized DNA molecules to UV irradiation, prevented both the supercoiled annular-supercoiled relaxed and the supercoiled relaxed-linearized transitions. The possible mechanisms of the UV-protective effect of AHB on DNA and their contributions to the resistance of dormant microbial forms to environmental factors are discussed.     

Structural changes in the lungs induced by different levels of hyperbaric oxygenation

Morphological and ultrastructural changes in the lungs of 30 rabbits placed into the altitude chamber with 100% O2 and the pressure of 2, 2.5, 3 and 4 ata for 60 min daily during 1, 2 and 3 weeks have been studied. Morphological changes in the lungs were shown to depend on the degree and duration of oxygen pressure. 2 ata for 60 min daily during two weeks or 2.5 ata for 60 min daily during one week were considered to be safe regimens of hyperbaric oxygenation. Microcirculatory disorders and dystrophic changes of the aero-hematogenic barrier (AHB), its increased permeability, the development of intraalveolar and interstitial edema are observed in the lungs at a higher pressure of 3 or 4 ata. The endothelium and type I alveolocytes are more sensible to high doses of hyperbaric oxygenation. Hydropic degeneration and exfoliation of cells from the basilar membrane are gradually increasing. Type II alveolocytes are more stable to the destructive action of hyperbaric oxygenation. Greater dystrophic changes in other AHB elements are associated with the hypertrophy of mitochondria and lamellar bodies. The described AHB changes are more expressed in atelectasis areas.     

Sharp increase in density of pulmonary and pericardial mast cells in monocrotaline-induced pulmonary hypertension in rats

Multifunctional granular mast cells (MCs) are involved in various pathological processes. The response of the MC population in the myocardium, pericardium, and lungs to pulmonary hypertension (PH) has been studied 8 weeks after the injection of monocrotaline. Five intact and five experimental rats were used. The density of MCs of different degrees of maturity was estimated in paraffin sections stained with Alcian blue and Safranin. The expression of PH was estimated by functional parameters using an echocardiogram and morphological markers. The MC density in the myocardium of intact and experimental rats was relatively low, i.e., 2–4 cells/mm². In the pericardia of intact rats, the MC density was 14 times higher than in the myocardia and increased by a factor of three in PH. In the myocardia and pericardia of intact and experimental rats, mature, Safranin-positive cells predominated (70–80%). In the lungs of intact rats, the MC density was about 30 cells/mm² and 98% of the cells were immature Alcian-positive cells. In lungs of rats with PH the mean density of MCs increased 5.6 times. In lungs of rats with severe pathologies, mature Safranin-positive cells appeared. The highest number of MCs in lungs was found in rats with distinctly pronounced disorders of myocardial function and marked histolological damages of myocardium and lung. The findings show the active reaction of the MC population to monocrotaline-induced PH, which stimulates the migration of immature MCs to the pericardium and lungs from the outside. The connection of cellular mechanisms of the development of PH with the function of MCs is not yet clear; however, the results of the present work indicate the important role of MCs in the pathogenesis of PH.     

Effect of emotional stress on the myocardial ultrastructure of rats occupying different hierarchical ranks in a group

Effect of immobilization stress on myocardial ultrastructure has been studied in rats occupying, according to the behavior, dominant, subdominant and "outcast" position in the group. The greatest changes are revealed in the myocardium of the dominant rats. This is explained by the fact, that mechanisms ensuring realization of certain functional systems in these animals require maximal energetic and emotional expenditure. And as the result--compensatory ability of their physiological function is lower than in animals of other ranks.     

Experimental Emphysema—Histologic Changes and Alterations in Pulmonary Circulation

Detailed study of the pathogenesis of bullous emphysema has been hampered by lack of a suitable animal model of this disease. Prolonged exposure of rats and dogs to elevated partial pressures of oxygen produced a chronic obstructive disease in the lungs of these animals which anatomically resembles bullous emphysema in man. The disease was characterized by extensive bullae formation, alveolar septal destruction, airway obstruction and pronounced circulatory changes. It is suggested that this condition in laboratory animals may serve as a model for the study of pulmonary obstructive disease.     

Protective and adaptive reactions of the air-conducting and respiratory portions of the lungs to exposure to atmospheric pollutants

A complex structural-functional investigation of protective-adaptive reactions of various parts in the lungs has been performed under inhalation of some toxic substances. To a continuous inhalation effect of 1,2-dichlorpropane, 132 non-inbred white rats have been subjected. At the first stage of the investigation, using specific loading tests, periods for formation of increased and decreased resistivity of the experimental animals have been defined. Under the given scheme of the experiment the state of a maximal resistivity develops by the 30th day of the influence, then it gradually decreases and in 60 days becomes significantly lower than in the control animals. Synchronous changes in resistivity and in loading of the respiratory organs are revealed. The structural-functional investigation of the pneumatic and respiratory parts of the lungs during the period of formation (in 5 days of the influence), at maximum (in 30 days of the influence) and at decreased resistivity (in 60 days of the influence) makes it possible to establish that functional activity of the aero-hematic, aero-epithelial barriers and the surfactant system of the lungs increases during the period of elevated resistivity and decreases at the stage of reduced endurance to the loading. A suggestion is made that, together with other factors, increasing functional activity in the systems studied is an essential component for formation of the elevated stability of the organism against toxic inhalation.     

Morphologic indices of the rat heart after colchicine application to the vagus nerve

By means of the light optic and electron microscopic methods atrial ganglia, myocytes, vessels of the right cardiac chambers have been studied in rats 2 days--3 weeks after application of 100 mcg of colchicine on the right nervus vagus. Certain changes of the neural fibers have been described at the area of the application. In the myocardium the microcirculatory bed, focal edema and hypoxic alterations of the myocyte ultrastructure have been revealed. In the ventrical ganglia destruction of some terminals of the preganglionar fibers, chromatolysis and vacuolization of single neurocytes, as well as intraganglionar granule-containing cells have been found. The changes described take place for 7 days and they nearly completely disappear in 10 days. A suggestion is made that some phenomena, in particular, destruction of the preganglionar fibers and changes of the cardiac microcirculatory bed are connected with certain disturbances of the quick transport of substances in the nervus vagus fibers.     

Mechanism of hypoxic pulmonary vasoconstriction involves ET(A) receptor-mediated inhibition of K(ATP) channel

There is controversy on the role of endothelin (ET)-1 in the mechanism of hypoxic pulmonary vasoconstriction (HPV). Although HPV is inhibited by ET-1 subtype A (ET(A))-receptor antagonists in animals, it has been reported that ET(A)-receptor blockade does not affect HPV in isolated lungs. Thus we reassessed the role of ET-1 in HPV in both rats and isolated blood- and physiological salt solution (PSS)-perfused rat lungs. In rats, the ET(A)-receptor antagonist BQ-123 and the nonselective ET(A)- and ET(B)-receptor antagonist PD-145065, but not the ET(B)-receptor antagonist BQ-788, inhibited HPV. Similarly, BQ-123, but not BQ-788, attenuated HPV in blood-perfused lungs. In PSS-perfused lungs, either BQ-123, BQ-788, or the combination of both attenuated HPV equally. Inhibition of HPV by combined BQ-123 and BQ-788 in PSS-perfused lungs was prevented by costimulation with angiotensin II. The ATP-sensitive K(+) (K(ATP))-channel blocker glibenclamide also prevented inhibition of HPV by BQ-123 in both lungs and rats. These results suggest that ET-1 contributes to HPV in both isolated lungs and intact animals through ET(A) receptor-mediated suppression of K(ATP)-channel activity.     

Immunocytochemical and ultrastructural correlates of the pineal inhibition of prolactin cell activity in blind-anosmic female rats

Summary The effects of the pineal gland on the light microscopic-immunocytochemical and ultrastructural appearance of pituitary mammotrophs were studied in female rats eight weeks after prepubertal blinding and olfactory bulbectomy.Blinding and anosmia resulted in a marked decrease in the size of the pars distalis concomitant with a reduction in the apparent number and size of PRL cells as compared with intact animals. Ultrastructurally, these cells appeared much less active than those of intact rats. The small and angular-shaped mammotrophs of blind-anosmic rats characteristically exhibited scant arrays of rough endoplasmic reticulum, small Golgi complexes with few immature secretory granules, few mature secretory granules and rare exocytosis patterns.Pinealectomy tended to reverse the effects of blinding and anosmia on pars distalis size and PRL cell size, apparent number and ultrastructure. In fact, the mammotrophs of blind-anosmic-pinealectomized rats were quite similar in ultrastructural appearance to those of intact rats.From these data we conclude that the pineal causes mammotroph hypotrophy and hypoplasia in blind-anosmic female rats.Supported by USPHS Biomedical Research Support Grant # RR 05675. The authors thank Dr. Bruce A. Richardson for his kind help with the immunocytochemistry     

The effect of alkylhydroxybenzenes on functional and operational stability of antibodies

The influence of alkylhydroxybenzene (AHB) homologues of various hydrophobicity on antibody interaction with corresponding antigens under denaturing conditions (functional stability) and suboptimal conditions (operational stability) was revealed. AHBs were found to modulate the antibody sensitivity to heat denaturation and UV irradiation and expand the pH range of activity in different directions. These effects were found to depend upon the specific chemical nature and the AHB concentrations applied. Mechanisms of the AHB effect and possible perspectives of their use as antibody stabilizers are discussed.     

Structural and functional indices of disturbances of oocyte maturation in androgenized rats after induction of ovulation with pregnant mare's serum and luliberin

The ultrastructure of oocytes from large follicles and the meiotic maturation rate of preovulatory oocytes of intact and androgenized rats were studied. The oocytes of defeminized animals were characterized by the lack of organelles and by changes of their structure. According to the rate of meiosis they were divided into two groups. The one entered the II stage metaphase earlier than in the control, the other was characterized by a slower chromosome transformation.     

Effect of splenin and splenic protein-free extracts on the adenosine deaminase activity in various organs of the rat

It has been shown that the adenosine deaminase activity of intact rats increases in such lymphoid organs as the thymus and spleen under the influence of splenic protein-free extracts dissolved in the ratio of 1:100. The enzyme activity in testes does not change but its decrease (by 26.2%) is observed in the adrenal glands under the influence of the splenic protein-free extract. An analogous effect is revealed in splenin and its fractions. The splenic protein-free extract increases (by 83%) the enzyme activity in the thymus of splenectomized rats as compared to intact animals but does not change it in a homogenate of testes.     

Ultrastructure of lung elastin and collagen in mouse models of spontaneous emphysema.

The tight-skin (Tsk) and beige (bg) mutants of the C57B1/6J strain of mouse spontaneously develop air-space enlargement reminiscent of human emphysema. To determine if this enlargement is accompanied by matrix destruction, as in the human disease, we examined the elastin and collagen matrices of the lungs of both mutants. The ultrastructure of these matrix components was separately visualized by scanning electron microscopy following controlled alkali digestion, which preserves collagen, and formic acid digestion, which enables visualization of elastin. Significant elastin destruction suggestive of an elastolytic process was observed in the lungs of Tsk mice. Thickening of elastin lamellae was observed in the lungs of bg mice, suggesting that congenital matrix remodeling may underlie air-space enlargement in this strain.     

Determination of products of acetohydroxy acid synthase by the colorimetric method, revisited

The enzyme acetohydroxy acid synthase (AHAS, EC 4.1.3.18) catalyzes two competing reactions of physiological importance: condensation of two molecules of pyruvate to form acetolactate (AL) or condensation of pyruvate and 2-ketobutyrate to form acetohydroxybutyrate (AHB). The activity of AHAS is most frequently analyzed using the Westerfeld method, in which the acetoin formed upon decarboxylation of AL is determined by colorimetric reaction with creatine and alpha-naphthol. However, there has been confusion as to the interpretation of the results of this assay in the presence of both substrates, conditions which lead to formation of both AL and AHB. By applying this assay to enzymatically prepared samples of AL and AHB which have also been analyzed by two other independent methods, we show here that the color yield for AHB in the commonly used assay is 35-40% that for equivalent amounts of acetoin or AL. The relative color yield is not significantly affected by varying the time or temperature of various steps in the color-forming reaction. This information could in principle be used, together with an independent specific assay for AHB, to determine the composition of an AHAS product mixture; it would, however, be less accurate than a simultaneous chromatographic method.     

Age-related alterations of mitochondria from muscle tissue

The ultrastructure of mitochondria of cross-striated muscles during aging was studied by electron microscopy. Mitochondrial ultrastructure was analyzed in the flight muscle of D. melanogaster (1- and 36-day-old) and in the cardiomyocytes and skeletal muscle of young and senile Wistar and OXYS rats (3- and 25-month-old). The mitochondria in the flight muscle samples of senile D. melanogaster flies were shown to have several types of peculiar age-related mitochondrial abnormalities corresponding to those described previously. Previously unknown changes were revealed in the ultrastructure of cardiomyocyte mitochondria in senile rats (both Wistar and OXYS). Substantial changes in the ultrastructure of subsarcolemmal mitochondria were found in the fibers of red skeletal muscle of senile OXYS rats. It has been shown that the subsarcolemmal mitochondria of red muscle fibers are a peculiar population of mitochondria with atypical ultrastructure. Initial changes in the ultrastructure of subsarcolemmal mitochondria were revealed even in 3-month-old OXYS rats. At the same time, the skeletal muscle mitochondria of senile Wistar rats maintain their morphological characteristics, and their ultrastructure corresponds to that of skeletal muscle mitochondria in 3-month-old Wistar rats.     

Lipid droplets of interstitial medullary cells of intact rat kidney with two-kidney Goldblatt hypertension.

Electron microscopic studies have been carried out of the interstitial cells (IC) of the renal medulla in rats with Goldblatt hypertension. Analysis of variance has not revealed any differences in the number of droplets of "unclamped" kidney in the hypertensive rats as compared to the normotensive rats ("resistant" rats, rats with unilateral nephrectomy, and intact rats) at periods from 3 weeks to 1 year. The total volume of the droplets in the IC cytoplasm in hypertensive and intact animals also revealed no difference 3 weeks after the beginning of the experiment. A positive correlation has been found between the number of the droplets and their volume but the low value of the correlation coefficient (r = +0.28) suggests that the number of the droplets cannot be a reliable indicator of the variation of the amount (volume) of thelipid material contained in them. Since it is just the latter parameter that carries the most information for evaluating the content of the droplet material in the IC, preference should be given to calculating the droplet volume rather than counting the number of droplets. The IC in the animals of the experimental groups revealed hypertrophy and hyperlasia of the endoplasmic reticulum and the Golgi complex, which were especially marked at the earlier stages of the experiments.     

Characteristics of the agents of acute suppurative destruction of the lungs in children]

The authors carried out bacteriological studies of the blood, the pleural cavity puncture material, the discharge from the bronchi in bronchoscopy, and also of smears from the nasopharynx of 40 children with acute purulent destruction of the lungs. Staphylococci, often in association with various Gram-negative bacilli, chiefly of the Pseudomonas genus, and Enterobacteriaceae family, prevailed in the cultures of the pathological material. Pathogenic staphylococcus was found in the nasopharynx of patients in 65% of cases. Along with staphylococci in over half of the patients there were revealed Gram-negative bacteria, and yeast-like Candida fungi. In the majority of patients the microbes isolated from the pharynx and the lungs were identical. In these cases bacteriological examination of pharyngeal smears can serve as an auxiliary method of laboratory diagnosis. The isolated straphylococcus strains possessed the majority of the pathogenicity signs; in the great majority of cases they were resistant to the antibiotics the most widely used in the therapeutic practice; among them strains of phage types 80, 54, 75, 77, and 81 prevailed. Thus, at different periods of the disease various types of the microbes prevailed in the materials obtained from the patients. In acute purulent destruction of the lungs bacteriological examination should be carried in dynamics.     

Morphometric analysis and topological organization of nuclear matrix in freeze-fractured electron microscopy

The ultrastructural organization of nuclear matrix, purified from intact or membrane-denuded rat liver nuclei, has been analysed by means of freeze-fracturing technique. This method avoids dehydration and embedding which, in conventional thin sectioning, partly distort or mask the matrix ultrastructure. The various matrix components, and mainly the peripheral lamina and the inner network revealed complex arrangements undetectable with conventional techniques. Morphometric analyses performed with a Texture Analysis System (TAS) Leitz, allowed to obtain precise information on the matrix constituents, based on the histograms of their size distribution. These textural characteristics have been utilized in order to identify, by means of a particular computer programme, the putative matrix localization within intact freeze-fractured nuclei.