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PubMed1979

Ultrastructure of the Legionnaires' disease bacterium. A study using transmission electron microscopy.

The Legionnaires' disease (LD) bacterium appeared ultrastructurally identical in human lung, egg yolk membrane, and artificial media, seen as a blunt or tapering rod measuring 0.3 to 0.9 micron in diameter and greater than or equal to 2.0 micron long. Greatly elongated forms were commonly found in cultures and yold sac membranes after 5 to 7 days of growth but were only rarely seen in human lung. The LD bacterium was clearly prokaryotic. Prominent features included electron-lucent nucleoids interspersed among areas of well-defined ribosomes; cleanly circumscribed cytoplasmic vacuoles or granular inclusions; and a double envelope enclosure, each portion consisting of a triple-layered "unit" membrane, approximately 75 A wide. Division always occurred as a pinching, nonseptate process typical of bacteria with a double, gram-negative type of envelope. No definite structure was seen in the periplasmic space that might represent the peptidoglycan layer. These features of the LD bacterium confirm earlier reports of the gram-negative staining reaction of organisms obtained from cultures and preliminary evidence of their gram-negative ultrastructure. We found no unique features that would aid in the ultrastructural differentiation of the LD bacterium from other small gram-negative bacilli.

Bacteria↗
PubMed1976

Bilirubin and paranitrophenol glucuronyl transferase activities and ultrastructural aspect of the liver in patients with chronic hemolytic anemias.

The hepatic ultrastructural aspect and the hepatic bilirubin (Bil-GT) and paranitrophenol (PNP-GT) glucuronyl transferase activities were studied in twenty subjects with a chronic hemolytic anemia (HA) and five subjects with an aplastic anemia. In chronic HA: the hepatic ultrastructural aspect showed mitochondrial abnormalities affecting structure (paracrystalline inclusions), size (giant mitochondria) and shape (irregular mitochondria); there was a decrease of Bil-GT activity in 80 percent of the patients. No connection could be shown between the HA etiology and the degree of the enzymatic activity decrease. The physiopathological mechanism of this enzymatic activity decrease is unknown; no deficiency of PNP-GT was observed; in chronic aplastic anemias there does not seem to be any modification, either of Bil-GT activity, or of hepatic PNP-GT activity. It is concluded that Bil-GT is often decreased in HA and that neither Bil-GT measurement nor the ultrastructural aspect of the liver distinguish chronic HA from Gilbert's syndrome.

Anemia, Aplastic↗
PubMed1976

[A comparative study of ultrastructural organization of the nonagglutinating vibrios and the causative agents of cholera].

A common plan of ultrastructural organization was revealed in a comparative study of the ultrastructure of the nonagglutinating El Tor and cholera vibrios: the presence of a three-layer cell wall and cytoplasmic membrane, the presence of vesicles on the external layer of the cell wall or between the cell wall and the cytoplasmic membrane; identity of the intracytoplasmic membranous structures; the presence of intracytoplasmic inclusions in the form of granules of various size and electron density; cell division by means of a band with the formation of two cells of equal size or of many bands in one cell, and also by the joining of the cytoplasmic membrane with the formation of rings at the sites of cell division. Identify of the ultrastructure of the vibrios under study can serve as confirmation of the views of the investigators who consider that nonagglutinating vibrios should be referred to a single V. cholerae species.

Cell Division↗
PubMed1976

[Ultrastructural changes in the arterioles of rats with experimental salt hypertension].

The ultrastructure of arterioles in experimental salt loading in rats was studied. It was established that prolonged feeding with salt-rich diet led to stable hypertension in some experimental animals, and ultrastructural changes in arterioles were noted only in rats which had developed stable hypertension. The changes in arterioles in experimental salt hypertension in principle were similar to those observed in other chronic forms of hypertensive states, but they developed slower and were less pronounced. The present study does not confirm the views advocated by some authors about a direct effect of salt on the ultrastructure of the arteriolar wall. The mechanism responsible for the changes in the arterial wall occurring in experimental salt hypertension remains unclear.

Animals↗
PubMed1999

[The effect of L-arginine on the ultrastructure of atrial cardiomyocytes in experimental hypercholesterolemia].

The results of electronmicroscopic study of the right atrium in experimental hypercholesterolemia revealed a disturbance of ultrastructural organisation of both cardiomyocytes and endothelial cells of blood microvessels. Intake of L-arginine--a precursor of synthesis of nitric oxide (NO)--with atherogenic diet was found to prevent to some extent the damage of ultrastructural organisation of cardiomyocytes and to stimulate the production of atrial granules. A significant number of secretory components, which differ in terms of structure and function, revealed in the endothelium of blood microvessels may testify to the fact that upon administration of L-arginine the paracrine effect of hormonal regulation is enhanced manifesting itself through an increase of synthesis and secretion of natriuretic hormone in atrial cardiomyocytes. A tissue hormonal system is displayed through an increase of synthesis and secretion of atrial natriuretic hormone in cardiomyocytes. On the other hand, a NO precursor L-arginine may produce a correcting effect upon the ultrastructure of endotheliocytes in hypercholesterolemia.

Animals↗
PubMed1976

[Ultrastructure of the vocal muscle and its morphological differences from the myocardium].

A comparative ultrastructural investigation of the M. vocalis in mammals has been carried out. Morphological differences between the vocal muscle and cardiac tissue are reported; a distinct classification of the M. vocalis according to a typisation of skeletal muscle fibers is presented. In all species investigated (man, dog, cat, guinea-pig and rat) the general ultrastructure of the sarcomeres as well as their mitochondrial content and the innervation pattern allow to classify the M. vocalis as to belong to the "fast twitch (white) skeletal muscle fibers. A single innervation was found with large motor endplates containing numerous synaptic infoldings. Structural specializations known to be characteristic for cardiac tissue, e.g. intercalated discs, T-tubules at the level of the Z-band and nuclei in a midst postion of the muscle cell could not be observed. The m. vocalis, therefore, cannot be considered to have histologically any relationship with cardiac tissue. The vocal muscle is described as a special type of skeletal muscle very similar to the extraocular muscles. The electron microscopic findings are discussed with respect to current theories of phonation. The myoleastic theory of phonation can be favoured according to our ultrastructural results.

Aged↗
PubMed1998

[Protein-energy malnutrition and hypobaric stress effects on ultrastructure of the heart muscle in rats].

A model that simulated nutritional and hypoxic stress is discussed. Wistar male adult rats were used in four groups: A1, A2, B1 and B2. A1 and A2 groups were fed with a diet whose composition was: 16% protein, 43% carbohydrate, and 6% lipids. Group B1 and B2 received the same type of diet but was restricted to 70% the amount consumed by groups A1 and A2. All groups were fed for 15 days. After these 15 days, the half of both groups were introduced into an hypobaric chamber simulating an altitude of 3,500 m for two hours. Pieces of the rats hearts were used for biochemical and ultrastructural studies. In group B a dear decrease in the body and the heart weight was observed. Also a decrement of the heart proteins concentration was noticed. On the contrary the mitochondrial proteins increased. These biochemical changes correlate with the ultrastructural changes observed in the same group in which a decrease of the myofibrilles and abnormal configurations of the mitochondria were found. The undemourishment and the hypobaric stress produced an evident alteration in the ultrastructure of the heart.

Animals↗
PubMed1999

Low grade fibromyxoid sarcoma: fine-needle aspiration cytology with histologic, cytogenetic, immunohistochemical, and ultrastructural correlation.

BACKGROUND: Although the histologic features of the recently described low grade fibromyxoid sarcoma are well established, to the authors' knowledge there are no reports in the literature describing the cytologic features of this tumor by fine-needle aspiration. Recognition of this lesion is important because of its indolent but metastasizing nature. METHODS: The authors retrospectively reviewed their surgical pathology files for cases of low grade fibromyxoid sarcoma with a preoperative fine-needle aspiration biopsy (FNAB); three such cases were found. Immunohistochemical studies were performed in all three tumors, ultrastructural examination was performed in two tumors, and fresh tissue for cytogenetic analysis was obtained in one tumor. RESULTS: All FNABs showed similar features. The aspirates were relatively hypocellular with an abundant myxoid background; the neoplastic cells contained oval to spindle shaped nuclei with minimal pleomorphism. No capillaries or areas of fibrous tissue were identified. Cytogenetic study of one case revealed no chromosomal abnormalities. The histologic findings were characteristic for this lesion. By immunohistochemistry the tumor cells showed diffuse and strong reactivity for vimentin only; at the ultrastructural level the neoplastic spindle cells had characteristics of fibroblasts. CONCLUSIONS: The cytologic features of low grade fibromyxoid sarcoma are not specific enough for a definitive diagnosis based on FNAB alone; however, correlating the cytologic and clinical findings can narrow the range of diagnosis. The differential diagnosis includes other myxoid lesions, in particular superficial or intramuscular myxoma and myxofibrosarcoma. In addition, the immunohistochemical and ultrastructural findings support a fibroblastic origin for this neoplasm.

Adult↗
PubMed1999

Histology and ultrastructure of liver and kidney following blood exchange with ultrapurified, polymerised bovine hemoglobin in comparison with hydroxyethyl starch.

Because of their oxygen binding capacity, cell-free hemoglobin solutions are promising blood substitutes. However, their clinical use has so far been limited by toxic side effects on liver and kidney until ultrapurification and chemical modifications have been established in the production process of hemoglobin-based oxygen carriers. The present study has been designed to examine structural changes of liver and kidney by light and electron microscopy after complete isovolemic blood exchange with a new ultrapurified bovine hemoglobin solution (UPBH-2) in eight beagle dogs. The results have been compared with a sham-operated control and eight animals having undergone blood exchange with hydroxyethyl starch (HES), a clinically used colloidal volume substitute. In the kidney, no changes were observed after blood exchange with UPBH-2 as compared with the sham control. These findings indicate sufficient tissue oxygenation and lack of renal toxicity. In contrast, histological signs of severe proximal tubular damage, eg, wide lumina, cytoplasmic protrusions, brush-border defects, and tubular necroses, were seen after blood exchange with HES. These changes are consistent with hypoxic tissue damage. In the liver, a slight increase in the number of single cell necroses was observed after UPBH-2 treatment as well as after blood exchange with HES. At the ultrastructural level, partial loss of microvilli and cytoplasmic protrusions of hepatocytes as well as swelling of endothelial cells were present in both groups, but slightly more pronounced in the UPBH-2 group. In all UPBH-2-treated animals, a marked diminution of glycogen-granula in hepatocytes was observed indicating an influence of UPBH-2 upon glycogen metabolism. Whereas the alterations of hepatocytes after nearly complete blood exchange with HES can be interpreted as a consequence of tissue hypoxia, the ultrastructural changes after UPBH-2 treatment cannot be attributed to hypoxic conditions, because improved tissue oxygenation has been demonstrated during treatment with UPBH-2. Hepatocyte damage was very discrete and comparable with the alterations observed after HES treatment. Hence, major hepatotoxicity can be excluded. The absence of significant adverse effects on the ultrastructural integrity of the kidney indicates that UPBH-2, owing to ultrapurification and polymerization, is an oxygen-carrying hemoglobin without acute renal toxicity.

Animals↗
PubMedDate not supplied

[Experimental study of the pathogenesis of frostbite. Part I. Pathohistologic and ultrastructural changes in tissues immediately after thawing].

Histopathologic and ultrastructural changes in the tissues of frozen extremities of Wistar rats were investigated immediately after thawing. Three experimental groups were formed: two were exposed to cryoinjuries of different intensity, while the third was the control one. Cryoinjury was caused by experimental model of local, controlled freezing of hind, right extremities. Immediately after thawing the tissue samples were taken from frozen right and unfrozen left extremities, in which histopathologic and ultrastructural changes were compared mutually and with control group, respectively. It was observed that the freezing directly caused ultrastructural and histopathologic damage of the tissues that were manifested immediately after thawing and were proportional to the intensity of freezing. Simultaneously, in the tissues existed complex circulatory disorders manifested in open arteriovenous shunts, venous congestion and microcirculatory insufficiency caused by evident spasm of arteriolae that could be considered to be very significant pathogenetic factor in ischemic damage of unfreezed tissues.

Animals↗
PubMed1998

[Comparative study on biological characteristics and ultrastructure of the fibroblasts derived from normal skin, hypertrophic scar and keloidin in vitro culture].

OBJECTIVE: This study was to investigate the in vitro cultivation, biological characteristics and ultrastructure of the fibroblasts derived from normal skin, hypertrophic scar and keloid, to elucidate the value of their application. METHOD: A comparative study was performed on cell proliferation, cell morphology, cytogenetic feature and cell ultrastructure of fibroblasts from normal skin, hypertrophic scar and keloid by means of the technique of in vitro culture. RESULT: The results indicated that the fibroblasts isolated from normal skin, hypertrophic scar and keloid exhibited similar morphology and growth rates. The cytogenetic feature and cell ultrastructure were also alike. CONCLUSION: According to our study and that of others, we conclude that it is entirely feasible to establish an in vitro culture model of fibroblasts from normal skin for investigation, prevention and treatment of scars.

Adolescent↗
PubMed1999

Ultrastructure of cultured and cryopreserved human corneal keratocytes.

PURPOSE: To describe the ultrastructural features of cultured and cryopreserved keratocytes. METHODS: Isolated human keratocytes were cultured with 10% fetal calf serum and 10 ng/ml acidic fibroblast growth factor. The 10% Me2SO and 10% human albumin were used as cryoprotective agents. Cells were cooled at 2 degrees C/min, then thawed at 37 degrees C, and subsequently recultured. They were studied by means of transmission electron microscopy (TEM). RESULTS: TEM of cultured keratocytes before cryopreservation showed a network of intact connecting cells. The average cell thickness was 2.4 microm in cross sections and 5.8 microm in frontal sections. The average nuclear thickness was 1.6 microm in cross sections and 3.7 microm in frontal sections. Nuclei appeared regular and oval in cross sections and indented in frontal sections. Organelles were found in greater amounts in frontal sections than in cross sections. Gap junctions, fenestrations along the cell surface, omega-shaped structures, fibrils, and filamentous networks also were found. Most of the just-thawed, suspended cells were elongated and condensed but had intact plasma membranes. These cells were surrounded by a granular material, corresponding to the albumin-containing thawing medium. Scattered isolated round cells displayed nuclear damage, cell edema, loss of organelles, and cell-membrane disruption. By the end of reculture after cryopreservation, cultured keratocytes displayed the same ultrastructural features as before cryopreservation. CONCLUSION: Cultured human keratocytes display many ultrastructural features of in situ keratocytes. These features are still present after reculture after cryopreservation. Cryopreservation induces necrosis in a small percentage of cells, which seems to be related to a relative lack of cell-membrane protection by the cryoprotectants used.

Cells, Cultured↗
PubMed1999

Cytochemical & ultrastructural alteration of cytoplasmic granules of rat peripheral blood neutrophils induced by chronic alcoholism & malnutrition.

The specific influence of malnutrition on the pathophysiologic changes induced by chronic alcoholism is controversial. In an attempt to determine and demarcate the effects of protein malnutrition from those produced by alcoholism and to evaluate the precise effect of alcohol per se on cytochemical and ultrastructural properties of rat polymorphonuclear neutrophil (PMN) granules, we investigated the influence of chronic protein malnutrition or chronic alcoholism alone and in combination, in rats. After a 4 month experimental period various PMN properties, such as cytochemical, morphometrical and ultrastructural, as well as neutrophil functions were studied. It was found that the degree of damage of PMNs induced either by ethanol or protein malnutrition alone was similar whereas their combination led to worsening of all markers of PMN functional ability. Ultrastructural changes of neutrophil granules including reduction, redistribution and atypical accumulation as well as appearance of autophagic vacuoles, confirmed their alteration which was emphasised by the additive pathophysiological interaction of alcoholism and chronic hypoprotein malnutrition.

Acid Phosphatase↗
PubMed1976

Platelet granulopathy: a new morphologic feature in preleukemia and myelomonocytic leukemia: light microscopy and ultrastructural morphology and cytochemistry.

We have previously reported on the ultrastructure of platelets in preleukemia and myelomonocytic leukemia. We referred to an unusual and distinct anomaly of the platelet granules found in 15 of 16 patients. In the present communication we wish to describe and illustrate the light microscopic appearance of giant anomalous granules. Close scrutiny of the platelet morphology and a search for the aforementioned platelet granulopathy are important in the evaluation of patients with myeloproliferative diseases. In this paper we describe and illustrate in more detail the ultrastructure and ultrastructural histochemistry of the abnormal granules. In those patients with the platelet granulopathy, we have conducted in vitro platelet aggregation studies and carried out an electron microscopic evaluation of the aggregates. At least some of the giant granules remained morphologically intact in advanced stages of the aggregation phenomenon, and thus they are probably composed of elements that were not released during aggregation.

Acid Phosphatase↗
PubMed1978

Ultrastructural effects of the chemical agents and moist heat on bacillus subtilis. II.--Effects on sporulating cells.

When sporulating cells are treated with the organic solvents (xylene, toluene, octanol and chloroform), with TCA or with moist heat (10 min at 80 degree C), the sporangial cells exhibit the same ultrastructural changes as do the vegetative cells. The forespores undergo similar changes after early but not after late treatment. Resistance toward the killing effect and toward ultrastructural alterations appear in the same order. One could correlate the appearance of resistances with precise ultrastructural events as follows:--xylene resistance: cortex formation (stage IV);--resistance to toluene, octanol and chloroform: coat development and cortex maturation (respectively early, middle and late stage V);--TCA and heat resistance: spore maturation (stage VI). The possible mechanisms of the chemical resistances are discussed.

Bacillus subtilis↗
PubMed2000

[Ultrastructure of skeletal muscle fibers in monkeys after space flight].

It is known that exposure of humans and animals to microgravity causes reduction in the cross-sected area of muscle fibers and muscle atrophy. These changes also involve ultrastructural alterations in muscle fibers. Therefore primates, that are physiologically close to humans, are to be examined to help a better understanding of the nature of these ultrastructural changes is muscles and muscle fibers. Although failed to find any relevant published data on the quantitative aspects of ultrastructural changes in muscle fibers of space-flown primates we believe that it is important to examine these aspects. The postflight study of monkey's m. soleus, and m. vastus lateralis did not reveal any significant changes in volume density of the myofibrillar apparatus. Mitochondria of m. soleus showed a distinct reduction in volume density, being more obvious in the subsarcolemmal zone than in the central one. Mitochondria of m. vastus lateralis showed a decrease (P > 0.05) in volume density. Following the flight, m. soleus and m. vastus lateralis of the monkeys showed a significant increase in the mean area of myofibrils, and a trend towards a decrease in the number of myofibrils per 100 micron 2. Besides, m. soleus showed a significant increase in the mean area of mitochondria, and a trend towards a decrease in the number of mitochondria per 100 micron 2. In m. vastus lateralis of the monkeys after space flight the number opf mitochondria tended to decrease and the mean area showed differential changes. It can be postulated that these phenomena may be associated with a reduction in the diffusion surface of mitochondria resulting from the diminished myofibrillar volume.

Animals↗
PubMed1998

Effects of ethinylestradiol-norethisterone acetate combinations on the ultrastructure of liver, kidney, ovary and endometrium cells.

Sexually mature female Wistar rats were given 0.05 mg ethinylestradiol (EE) + 0.5 mg norethisterone acetate (NET), or 0.1 mg EE + 1.0 mg NET for 6 or 12 sexual cycles, i.e., for 30 or 60 days. Rat hepatocytes, renal proximal tubule cells, ovarian granulosa cells and endometrial gland cells showed ultrastructural changes that correlated with the dose and duration of EE/NET treatment. The most common ultrastructural features were as follows: reduced RER, mitochondrial damage, and an increased number of lysosomes. The study has shown that EE/NET combinations used in oral contraception produce ultrastructural lesions, which may impair protein biosynthesis and energy production processes, and may simultaneously enhance cellular catabolism.

Animals↗
PubMed1999

Electrophysiological and ultrastructural analysis of the neuromuscular blockade and miotoxicity induced by the Micrurus nigrocinctus snake venom.

Micrurus nigrocinctus is the most abundant coral snake in Central America. The venom of this specie induced a concentration-dependent (10-20 micrograms/ml) depolarization in the isolated mouse phrenic nerve-diaphragm preparations incubated at 37 degrees C. d-Tubocurarine (10 micrograms/ml) and (alpha beta ungarotoxin (3-5 micrograms/ml) were able to partially protect against the depolarization induced by the venom (10 micrograms/ml), suggesting the involvement of subsynaptic cholinergic receptors. This venom (10 micrograms/ml) also increased the frequency and amplitude of miniature end-plate potentials (mepps) during the first 10-20 min of incubation. Subsequently, the mepps progressively decreased and disappeared after 60 min. These responses were accompanied by ultrastructural changes involving the nerve terminals, the subsynaptic junctional folds and the muscle mitochondria. The synaptic gutter was shallow and, very often, "shrunken" terminals with omega-shaped axolemmal indentations and a decreased number of synaptic vesicles were present. A common finding was the presence of numerous finger-like, membrane-bounded bodies interposed between the terminal and the Schwann cells or postsynaptic sarcolemma. The preincubation of the venom with specific antivenom or the incubation of the preparations at room temperature (24-26 degrees C) reduced the number and intensity of the ultrastructural alterations. The last finding suggests the involvement of a enzymatic process, probably a phospholipase A2, present in the venom. There was a good correlation between the electrophysiological and ultrastructural effects induced by the venom which allow us to conclude that M. nigrocinctus venom has a presynaptic action in the initial stages of intoxication followed by sub- and postsynaptic effects, the last being the most important cause of neuromuscular blockade. A direct action of the venom on muscle fibers may also contributes to the irreversible blockade.

Animals↗