Preservation of alveolar type II pneumocyte lamellar bodies for electron microscopic studies.

Simultaneous fixation with glutaraldehyde and osmium tetroxide, followed by an uranyl acetate (UA) treatment before dehydration and embedding (Hirsch and Fedorko 1968) ensures a very good preservation of lamellar bodies (LB's) as well as of the cellular membranes in type II pneumocyte. The uranyl acetate treatment appeared to be the most efficient step of the procedure. The morphological aspect of lamellar bodies after such a preparation was similar to that observed after freeze-etching of lipid retaining methods. Moreover, the Hirsch-Fedorko procedure is very simple and can easily be used for routine ultrastructural and radioautographic studies. On the other hand, it appeared that the uranyl acetate phospholipid "complex" is very sensitive to the pH of chemical solutions used after sectioning. The "complex" is variously dissolved by alkaline solutions, photographic developers or stains. The best preservation of ultrastructure was obtained with neutral or acidic developers and acidic stains.     

Autoradiographic and electron microscopic studies of minced cardiac muscle regeneration in the adult newt, notophthalmus viridescens.

The regenerative response of minced cardiac muscle grafts in the adult newt was studied using autoradiography and electron microscopy. One-sixteenth to one-eighth of the newt ventricle was amputated, minced, and returned to the wounded ventricle. At five days after grafting, no reorganization of graft msucle pieces was apparent and there was degeneration of much of the muscle graft. Another, smaller population of 5-day myocytes had euchromatic nuclei and intact sarcolemmae. In 10- and 16-day grafts, continuity between ventricular and graft lumina was established and coalescence of graft pieces was apparent. Ultrastructurally, 10- and 16-day graft myocytes appeared to have fewer myofibrillae and increased amounts of rough endoplasmic reticulum, polyribosomes, Golig complexes, and dense bodies when compared to uninjured ventricular myocytes. The peak of proliferative activity of graft cells was observed at 16 days. Electron microscopic autoradiography revealed breadkdown of myofibrillar structure in labeled myocytes, whereas in myocytes in the later stages of mitosis only scattered myofilaments and no Z bands were present. By 30 days, grafts appeared as an integrated structure composed primarily of cardiac muscle. Myocytes of 30-day grafts were observed in various stages of myofibrillogenesis and contained numberous 10-nm filaments. Seventy-day graft mycoytes had numberous well organized myofibrillae and intercellular junctions similar to those seen in uninjured ventricular myocytes.     

Light optical and electron microscopic changes in striated muscle tissue under the effects of sea water and thymogen in experimental animals]

Effect of sea-water with t degrees +4 degrees to +8 degrees C with time of exposure from 30 minutes to 24 hours on pelvic extremities was studied in 200 rabbits, optical and ultrastructural studies were carried out. It was revealed that effect of sea-water causes damage of striated tissues' structure and death of animals. Prophylactic injections of thymogen stabilized ultrastructure and raised survival, if time of exposure did not exceed 12 hours.     

Light, fluorescence and electron microscopic studies of rabbit subclavian glomera.

The subclavian glomera (aortic bodies) of young New Zealand white rabbits were studied with the light, fluorescence, and electron microscopes. Two cell types were identified: type I, granule-containing (chief) cells, and type II, agranular (sustentacular) cells. The type I cells possessed large nuclei, the normal complement of cytoplasmic organelles and numerous electron-opaque cytoplasmic granules. The type II cells were agranular with attenuated cytoplasmic processes which partially or completely ensheathed the type I cells. The glomera were well vascularized. Capillary endothelial cells contained numerous pinocytotic vesicles, but few fenestrae. Two profiles of nerve terminals were observed. One, apposing the type I cells, contained numerous electron-lucent vesicles, several dense-cored vesicles, mitochondria and possessed membrane specializations resembling those usually observed in synaptic zones. The other profile contained abundant mitochondria and a few electron-lucent and dense-cored vesicles. Structural specializations were not observed on the apposed membranes of these terminals or adjacent to type II cells. Fluorescence histochemistry revealed an intense yellow-green fluorescence in the glomera, which indicated the presence of biogenic amines, possibly primary catecholamines or an indolamine. The electron-opaque granules observed in the type I cells were believed to be the storage sites for these amines. The subclavian glomera were found to be morphologically similar to the carotid body which is a known chemoreceptor.     

Further electron microscopic studies on the expression of Escherichia coli group II capsules.

The de novo expression of Escherichia coli K1, K5, and K12 capsules was analyzed with immunoelectron microscopy in temperature upshift experiments, with upshift from 18 degrees C (capsule restrictive) to 37 degrees C (capsule permissive). Newly produced capsular polysaccharides appeared at the cell surface atop membrane adhesion sites (Bayer's junctions). After plasmolysis of the bacteria at an early expression stage, the capsular polysaccharides were labeled at discrete sites in the periplasm by the immunogold technique. After temperature upshift in the presence of carbonyl cyanide m-chlorophenylhydrazone (CCCP) or chloramphenicol, the polysaccharides were labeled in the cytoplasm.     

Dose‐dependent actions of curcumin in experimentally induced myocardial necrosis: a biochemical,histopathological, and electron microscopic evidence

Curcumin, an active component of turmeric, is a well‐known antioxidant due to its reactive oxygen species (ROS) scavenging property. However, some in vitro studies have suggested that curcumin induces generation of ROS at higher doses and thus exerts pro‐oxidant effect. We demonstrate, for the first time, the dose‐dependent effects of curcumin in isoprenaline‐induced model of myocardial necrosis in rats. The animals were assigned to control, isoprenaline and three curcumin treatment groups. Curcumin (100, 200, and 400 mg/kg) and vehicle (dimethyl sulfoxide) were administrated orally for 15 days and isoprenaline (85 mg/kg, s.c.) was given to curcumin treated and isoprenaline group on 13th and 14th day, respectively. Thereafter, on 15th day, the animals were sacrificed for biochemical analysis along with histopathological and ultrastructural examination. There was an increase in glutathione, superoxide dismutase (SOD), creatine kinase‐MB (CK‐MB) and lactate dehydrogenase (LDH) levels, decrease in thiobarbituric acid reactive substances (TBARS), and preservation of myocardial architecture in the curcumin (100 and 200 mg/kg) treated groups. However, at 400 mg/kg dose there was ineffectual protection against isoprenaline‐induced myocardial damage. Instead, there was significant lipid peroxidation as evident by increased levels of TBARS (93.87 ± 9.93, p < 0.0001) and decrease in CK‐MB (206.32 ± 13.54, p < 0.0001) and LDH (134.26 ± 9.13, p < 0.01) as compared to the two lower doses. Hence, it can be concluded that curcumin augments endogenous antioxidant system at lower doses but mediates ROS induction at higher concentration leading to myocardial damage. Copyright © 2009 John Wiley & Sons, Ltd.     

Interactions of cardiac glycosides with cultured cardiac cells: II. Biochemical and electron microscopic studies on the effects of ouabain on muscle and non-muscle cells

Electron microscopic and biochemical studies revealed a salient difference in the response to toxic doses of ouabain by cultured cardiac muscle and non-muscle cells from neonatal rats. Progressive cellular injury in myocytes incubated with 1 · 10^?4–1 · 10^?3 M ouabain ultimately leads to swelling and necrosis. The morphological damage in myocytes was accompanied by a drastic decrease in ¹⁴CO₂ formation from ¹⁴C-labeled stearate or acetate but not glucose. Neither morphological nor biochemical impairments were observed in non-muscle cells. The interaction between ouabain and the cultured cells, using therapeutic doses of ouabain (i.e., <1 · 10^?7 M), was characterized. Two binding sites were described in both classes of cells, one site is a saturable K⁺-sensitive site whereas the other is non-saturable and K⁺-insensitive. The complexes formed between the sarcolemma receptor(s) and ouabain, at low concentrations of the drug (e.g., 7.52 · 10^?9 M), had K_d values of 8.9 · 10^?8 and 2.3 · 10^?8 M for muscle and non-muscle cells, respectively. The formation and dissociation of the complexes were affected by temperature and potassium ions.     

Epicardial formation in embryonic chick heart: computer-aided reconstruction, scanning, and transmission electron microscopic studies

Epicardial formation in the embryonic chick heart from initial to final stages was revealed by means of computer-aided reconstructions based on serial resin sections for light microscopy, with further detailed observations using scanning and transmission electron microscopy. The origin of the epicardium was recognized as protrusions of mesothelial cell clusters on the right side of the external surface of the sinus venosus at 23 somites (stage 14+). These protrusions elongated to give rise to several villous processes, the tips of which eventually touched the dorsal wall of the embryonic heart at 30 somites (stage 17). Originating from these adhesion sites, mesothelial cells spread gradually onto myocardial cells in all directions to form a monolayered sheetlike cover. Thus, by stage 23, the ventricle was completely overlaid with epicardium, and blood-island-like structures appeared within the subepicardial layer. The atrium was not enveloped by epicardium until stage 25, and the extreme distal end of the bulbus cordis was reached by the advancing epicardium at stage 27. A chronological table of epicardial formation in the chick heart is presented.     

Microbial adjuvant and autoimmunity. II. Production of lesions in mice immunized with syngeneic tissue extracts together with the capsular polysaccharide of Klebsiella pneumoniae.

The target organs of mice immunized with the respective syngeneic tissue extracts together with the capsular polysaccharide of Klebsiella pneumoniae (CPS-K) as a powerful adjuvant were examined for production of lesions. In 15 out of 24 mice injected three times or more with syngeneic eyeball extracts and CPS-K adjuvant at intervals approximately 30 days, severe eyeball lesions developed in which the normal structure was almost completely lost. A large part of the eyeball tissue of these mice was replaced by infiltration with cells such as lymphocytes, plasma cells and other mononuclear cells and by connective tissue. No definite eye lesions developed in mice injected with CPS-K alone, eyeball extracts alone or eyeball extracts emulsified in complete Freund's adjuvant (CFA). In all of mice injected four times with thyroid gland extracts and CPS-K at intervals of approximately 30 days, definite thyroid gland lesions were produced. In three out of five mice of this group, the thyroid lesions were so severe that the normal thyroid follicular structure was almost completely lost, and a large part of the thyroid gland was replaced by infiltration with lymphocytes, plasma cells and other mononuclear cells and in part by connective tissue. In only one out of five mice injected with thyroid gland extracts emulsified in CFA, definite but milder thyroid gland lesions developed. No definite thyroid lesions developed in the remaining four mice of this group and also in any of the mice injected with thyroid gland extracts alone or CPS-K alone. Repeated injections of lymphoid tissue extracts and CPS-K also induced pathological changes in the spleen and lymph nodes, although less marked than those in the cases of the eyes and thyroid gland. The most remarkable change was a decrease in numbers of small lymphocytes at the areas surrounding the central arterioles in the white pulp of the spleen and the post-capillary venules in the cortex of the lymph nodes. From these results it has been concluded that our system can provide new and useful models for autoimmune diseases in man.     

Light and electron microscopic studies on osmoregulatory tissue in the developing brown shrimp, Penaeus aztecus

In larval and early postlarval brown shrimp, Penaeus aztecus, portions of the branchial chamber are lined by a tissue which appears ultrastructurally to be modified for osmoregulation. The distribution of this tissue, the larval stages in which it occurs, and its appearance with the light and electron microscope are presented. The significance of the distribution and ultrastructure of this modified tissue is discussed.     

Cytophotometric and electron microscopic studies of chronic human skin lymphomas. II. Research on lymph node involvement

Results of electron microscopic and cytophotometric studies of biopsy material from lymph nodes of patients with cutaneous lymphomas with low degree of malignancy are discussed, with special reference to early diagnostic criteria of the disease. Specific characteristics of tumor tissue involve the presence of atypical lymphocytes with marginal condensed chromatin extrusions of nuclear material, deep invaginations of the nuclear membrane, nuclear pockets, excess of the mean DNA content per nucleus above the diploid standard level, more than 5% of nuclei being in the hyperdiploid area. Electron microscopic and cytophotometric methods allowed to diagnose the tumor injury of lymph nodes, when the traditional histological techniques revealed no signs of malignancy.     

Progressive multifocal leukoencephalopathy: two cases with electron microscopic and viral studies.

Part I of this review described the pathogenesis of lung cancer and emphasized that it was largely a preventable disease. In the present paper, attention is drawn to the prevalent but false impression that treatment of established disease is quite in-effective. In eight consecutive series of cases (over 2300 patients) the authors have seen a change in the clinical environment in which lung cancer is treated—from one of discouragement and apathy to one of outspoken encouragement and enthusiasm.Complete preoperative assessment—an evaluation of the biology of the tumour-host relationship as well as technical resectability—avoids unnecessary surgical intervention and stimulates a trend to earlier referral. This has permitted increasing use of resection with a declining mortality and a continuing improvement in overall survival. On the basis of present resectability rates (37.5%) and a 39% five-year survival rate in those who have had curative resection, it is estimated that current over-all five-year salvage should exceed 13%. This is more than a five-fold increase in survival for all patients compared to that achieved by treatment before 1952.