An ultrastructural study of osmiophilia in normal human oesophageal epithelium

Summary Oesophageal biopsies were obtained from patients with normal oesophagi during fibre-optic endoscopy for upper gastro-intestinal symptoms. They were studied with the prolonged osmication technique. The forming face of the Golgi apparatus was demonstrated in the basal and lower prickle cells. These cells also showed osmium deposition in their mitochondria, endoplasmic reticulum, perinuclear cisternae and lysosomes. The capillary endothelial cells also showed osmium deposition in their Golgi apparatus and endoplasmic reticulum.     

Localization in the cell of the protein forming ATP-dependent potassium-selective channels in a bilayer lipid membrane. An ultrastructural study

The localization in cell of the protein forming in BLM the ATP-dependent potassium-selective channels was studied. The electron-microscopic investigation of rat liver and heart tissue sections after their incubation with Abs against the studied protein and visualization of the protein with secondary Abs conjugated with colloid gold were carried out. The colloid gold particles were observed both in mitochondrial membranes and in membranes of endoplasmic and sarcoplasmic reticulum. In heart mitochondria these particles were significantly greater then in liver mitochondria. The detection of the channel-protein localization both in mitochondria and reticulum, as well as structural similarity between the mitochondrial channel and the precursor of calreticulin suggests that the channel protein belongs to the calreticulin family. The possible function of the studied protein as a channel subunit of the mitochondrial ATP-dependent potassium channel is discussed.     

Penile lentiginosis. An ultrastructural study.

This study on five patients has revealed more extensive alterations to melanocytes than previously reported, and emphasizes the fact that depigmentation is an essential element of the condition. In hyperpigmented areas, melanocytes were increased in number along the basal layer of the epithelium, were hyperactive, and in some cases contained bizarre melanosomes. In two cases there was suggestion of a defect in melanosome transfer to keratinocytes. Lymphocytes were closely apposed to melanocytes, and, in hypopigmented areas, were clearly involved in their disintegration. In depigmented areas, there was complete absence of melanocytes and of melanosomes in keratinocytes, and lymphocytes were present in the basal layer. In general, the appearances did not resemble melanoma in situ with spontaneous regression, although a second biopsy of one patient after one year did reveal features of melanocytes suggestive of an early stage of this condition. The study has provided no clear information as to the initial cause of the condition, but the manner of destruction of melanocytes suggests an immune reaction. Neither has it been of assistance in suggesting a more precise name for it.     

Glucose-6-phosphate dehydrogenase in rat lung alveolar epithelial cells. An ultrastructural enzyme-cytochemical study

Glucose-6-phosphate dehydrogenase (G6PD) is the key enzyme of the pentose phosphate pathway in carbohydrate metabolism, and it plays an important role in cell proliferation and antioxidant regulation within cells in various organs. Although marked cell proliferation and oxidant/antioxidant metabolism occur in lung alveolar epithelial cells, definite data has been lacking as to whether cytochemically detectable G6PD is present in alveolar epithelial cells. The distribution pattern of G6PD within these cells, if it is present, is also unknown. The purpose of the present study was to investigate the subcellular localization of G6PD in alveolar cells in the rat lung using a newly-developed enzyme-cytochemistry (copper-ferrocyanide) method. Type I cells and stromal endothelia and fibroblasts showed no activities. Electron-dense precipitates indicating G6PD activity were clearly visible in the cytoplasm and on the cytosolic side of the endoplasmic reticulum of type II alveolar epithelial cells. The cytochemical controls ensured specific detection of enzyme activity. This enzyme may play a role in airway defense by delivering substances for cell proliferation and antioxidant forces, thus maintaining the airway architecture.     

Localization in a cell of a protein forming the ATP-dependent potassium-selective channels in the bilayer lipid membrane. An ultrastructural study

The localization in the cell of the protein forming the ATP-dependent potassium-selective channels in the bilayer lipid membrane has been studied. The electron microscope investigation of rat liver and heart tissue sections after their incubation with Abs against this protein and the visualization of the protein with secondary Abs conjugated with colloid gold were carried out. Colloid gold particles were observed both in mitochondrial membranes and in membranes of endoplasmic and sarcoplasmic reticulum. In heart mitochondria, these particles were significantly greater than in liver mitochondria. The localization of the channel protein both in mitochondria and reticulum, as well as the structural similarity between the mitochondrial channel and the precursor of calreticulin suggest that the channel protein belongs to the family of calreticulins. The possible function of the protein as a channel subunit of the mitochondrial ATP-dependent potassium channel is discussed.     

Acute eosinophilic leukemia. An ultrastructural study.

Observations on a 32 year old male are described. Hematological examination demonstrated leukocytosis with circulating blastosis and dystrophic hypereosinophilia of the blood and bone marrow, with cells at various stages of maturation. Cytotoxic chemotherapy led to complete remission for 5 months followed by a terminal relapse. No features in favor of an "eosinophilic collagenosis" were revealed at autopsy. Repetitive ultrastructural studies performed during evolution of the illness demonstrated considerable anomalies of the eosinophil line. The present observation thus shows the clinical, evolutional, cytological and autopsy criteria of an acute eosinophilic leukemia.     

Localization of calcium in presynaptic nerve terminals. An ultrastructural and electron microprobe analysis

Ultrastructural techniques and electron probe microanalysis were used to determine whether or not the smooth endoplasmic reticulum (SER) within presynaptic nerve terminals is a Ca-sequestering site. The three- dimensional structure of the SER was determined from serial sections of synaptosomes. The SER consists of flattened cisterns that may branch and are frequently juxtaposed to mitochondria. To investigate intraterminal Ca sequestration, synaptosomes were treated with saponin to disrupt the plasmalemmal permeability barrier. When these synaptosomes were incubated in solutions containing Ca, ATP, and oxalate, electrondense Ca oxalate deposits were found in intraterminal mitochondria, SER cisterns, and large vesicular profiles. Saponin- treated synaptosomes that were incubated in the presence of mitochondrial poisons contained electron-dense deposits within SER cisterns and large vesicular profiles, but very rarely in mitochondria. Similar deposits were observed within saponin-treated synaptosomes that were not post-fixed with OSO4, and within saponin-treated synaptosomes that were prepared for analysis by freeze-substitution. Electron-probe microanalyses of these deposits confirmed the presence of large concentrations of Ca. When oxalate was omitted from the incubation solutions, no electron-dense deposits were present in saponin-treated synaptosomes. In other control experiments, either the Ca ionophore {"type":"entrez-nucleotide","attrs":{"text":"A23187","term_id":"833253","term_text":"A23187"}}A23187 or the Ca chelator EGTA was added to the incubation media; electron-dense deposits were very rarely observed within the intraterminal organelles of these saponin-treated synaptosomes. The data indicate that presynaptic nerve terminal SER is indeed a Ca- sequestering organelle.     

Adrenomedullary chromaffin cells of the rat. An ultrastructural study

Adrenomedullary chromaffin cells of the rat were studied at the ultrastructural level. Chromaffin cells contained a large population of electron-dense-core vesicles of two types, one very electron-dense (norepinephrine) and the other moderately electron-dense (epinephrine). The vesicles showed an even distribution pattern in the cytoplasmic matrix. No physical contacts were observed between cytoplasmic and vesicle membranes to indicate exocytosis, a mechanism frequently observed in the hamster. For chromaffin cells to be used as a transplantable source of dopamine, both the cells and vesicles must survive the trauma of denervation and vascular elimination or alternatively acquire the two factors from the transplantation site.     

Immunocompetent cells in the starfish Asterias rubens. An ultrastructural study

Cells from the axial organ of the starfish Asterias rubens were fractionated into two populations, adherent and non-adherent to nylon wool. In both populations the ultrastructural study revealed the presence of cells resembling the lymphocytes of the vertebrates, as well as phagocytic, peroxidase positive cells. The lymphocyte-like cells in the non-adherent population (average diameter 4 mu) have a high nucleo-cytoplasmatic ratio and are morphologically similar to Th lymphocytes while the adherent cells (average diameter 5.5 mu) are more similar to Bm lymphocytes. These observations are in line with the hypothesis that there exist, in the starfish, a primitive immune system with characteristics resembling those of the immune system of vertebrates.     

Early contacts between fibroblasts. An ultrastructural study

Pairs of chick heart fibroblasts have been studied with the light microscope and then fixed in situ for electron microscopy at varying times after they have been seen to make contact with each other. The resultant electron micrographs show that areas of specialisation begin to develop within 20 sec of the contact being made. These specialisations resemble those seen in isolated chick heart fibroblasts where the cell comes close to the substrate and are thought to be areas of adhesion. The development of these areas and their associated microfilaments is described and an attempt is made to correlate this with the stages of the contact inhibition phenomenon.     

An ultrastructural study of the renal medulla in experimental acute pyelonephritis.

Experimental acute pyelonephritis was produced in rats by a combination of intravenous administration of Escherichia coli, strain IMRU-54, and temporary unilateral mechanical ureteral obstruction. Structural alterations of the renal medulla were studied by light and electron microscopy. Major cellular alterations occurred in the vasa recta. Tubular and interstitial cells demonstrated minimal alterations after the brief period of acute inflammation. Polymorphonuclear leukocytes within tubular lumina contained structures resembling E. coli in nonprotoplasts-like form. Numerous protoplast-like organisms, to the exclusion of any other structural forms, were detected within the interstitium of the inner medulla. Nonprotoplast-like structures resembling E. coli were rarely observed in interstitium of the inner medulla. Following relief of ureteral obstruction, clearance of acute inflammation was rapid. In conclusion, hemoatogenous acute pyelonephritis induced by E. coli, IMRU-54, is able to inflict cytological and ultrastructural damage to structural elements of the inner and outer medulla of rats. Vasa recta incurred prominent alterations in endothelia and basement membranes, whereas tubular epithelia and interstitial cells had relatively good structural preservation. The data suggest that intravenously administered E. coli is capable to revert to a protoplast-like structure in the inner medulla.     

Localization of cations by pyroantimonate. I. Influence of fixation on distribution of calcium and sodium. An approach by analytical ion microscopy

A modification of the potassium pyroantimonate (PA) method for localization of calcium and sodium was tested using skeletal muscle of mouse. Massive diffusion of these cations, depending on the method of fixation, was demonstrated by analytical ion microscopy (AIM) images on the optical microscopy level. Rapid penetration of the fixative appeared to be the principal condition that reduced diffusion of Ca2+ and Na+. Paraformaldehyde (2%) appeared more efficient than glutaraldehyde (1%) for preserving metal composition. Addition of 1% phenol strikingly improved the quality of the AIM images. Supersaturated PA (4%) appeared to retain about 10 times more sodium in the tissue than insaturated PA (2%). The role of different buffers is also discussed, particularly collidine, which permitted better preservation of sodium. Fixation with this buffer should be very useful for study by AIM of large-scale distribution of sodium. These results are analyzed at the ultrastructural level in the accompanying report.     

Localization of triphosphoinositide in the cochlea. An electronmicroscopic immunocytochemical study

Triphosphoinositide (TPI) has been demonstrated to be a receptor for aminoglycosides in the cochlea and may regulate ionic permeability by its binding with Ca++. This phospholipid was localized by a protein A-gold technique in the cochlea at the electronmicroscopic level. TPI was prepared by a neomycin column and antibodies to it were raised in rabbits. The antibody used in this study reacted virtually only to TPI among the tested lipids. TPI was localized mainly at stereocilia, cuticular plates, head plates of Deiters' cells, plasma membrane, and mitochondria of various cells in the organ of Corti. In the vascular stria, TPI was found mainly at the plasma membrane of basal infoldings of the marginal cells. Possible physiological and pathophysiological roles of TPI in the cochlea are briefly discussed.     

Early contacts between normal fibroblasts and mouse sarcoma cells : An ultrastructural study

When chick heart fibroblasts and mouse sarcoma (S180) cells make contact with each other, an ultrastructural study shows no formation of cortical specialisations at the area of contact, as are seen in the case of fibroblast-fibroblast contacts.     

Sympathetic ganglia in diabetes. An ultrastructural and stereologic study

An ultrastructural and stereologic study was performed on sympathetic ganglia collected at surgery from eight diabetic patients, seven age-matched non-diabetics and six subjects with glucose intolerance. All patients underwent surgery because of arteriosclerosis obliterans. Volume density (Vv) and mean thickness (tau) of the satellite cell layer were found to be significantly higher in diabetics (P less than .001 and P less than .002, respectively) than in the other two groups, between which no difference was found. Vv and tau of the endothelial basal lamina were found to be increased in the diabetic and glucose-intolerance groups at a low level of significance (P less than .05). Satellite cells are thought to exhibit a close similarity to Schwann cells. Ultrastructurally, cytoplasmic edema, increase of subcellular organelles and lipid inclusions were consistently observed in satellite cells from diabetic patients. The results suggest that there may be a metabolic impairment of these cells in diabetes.