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Biomedical subjects

E N Albert

Publications and source records attributed to E N Albert.

At least 19 recordsLinked to original sources
PubMed1988

Morphological changes in cerebellum of neonatal rats exposed to 2.45 GHz microwaves.

One-day and six-day old Sprague-Dawley rats were exposed in the far field to 2.45 GHz (cw) microwaves at 10 mW/cm2 for five consecutive days, 7 hours per day (SAR 2W/kg). Pups were euthenized one day after exposure and the cerebella processed for light and electron microscopy. Matching cerebellar sections and folia from irradiated and sham irradiated animals were examined. Light microscopic examination revealed the presence of small deeply-stained cells with hyperchromatic pyknotic nuclei within the external granular layer (EGL). The number of these pyknotic cells in the experimental animals was nearly twice that in the controls. The Nissl bodies in Purkinje cells were finely dispersed. In some experimental animals mononuclear cellular infiltration was demonstrated. Under the electron microscope the deeply-stained pyknotic small cells presented electron dense nuclei with clumped chromatin, extrusion or disintegration of the nucleus, ruptured nuclear membrane, and the vacuolization of the cytoplasm. Eventually these cells became phagocytosed by surrounding EGL cells. Most of the Purkinje cells of experimental animals showed small, disorderly arrays of rough endoplasmic reticulum (RER) instead of the typical orderly stacks of parallel arrays. These observations suggest that microwave radiation may interfere with early genesis of cerebellar microneurons and alter the metabolic status of Purkinje cells. However, this effect might be reversible.

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PubMed1987

Effect of amplitude-modulated 147 MHz radiofrequency radiation on calcium ion efflux from avian brain tissue.

Cerebral cortex tissue slices and cerebral hemispheres prepared from Gallus domesticus chicks were exposed to 147 MHz radiofrequency radiation, amplitude modulated at 16 Hz and applied at a power density of 0.75 mW/cm2, to determine the effect of such exposure of 45Ca2+ efflux from the avian brain tissue. Statistical analysis of these data demonstrates that such exposure has no significant effect on 45Ca2+ efflux.

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PubMed1985

Structural and functional characteristics of cardiac myocytes.

Canine and rat cardiac myocytes, prepared by proteolytic disaggregation, retain morphological and topographical features of intact tissue. Cells are rod-shaped and are cleanly separated at their sarcolemmal and intercalated disc borders. Cells demonstrate glucose and fatty acid uptake and metabolic features comparable to intact organ, and are responsive to insulin and epinephrine, but nor carnitine. Although rat cardiac cells contain immunodetectable lipoprotein lipase, they are incapable of metabolizing extracellular lipoprotein triglyceride, nor the glycerol or monoglyceride moieties of the triglyceride. These and other metabolic characteristics suggest that cardiac cells can provide a useful cellular model for studies on cardiac pathophysiology.

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PubMed1979

Morphological and metabolic studies on adult cardiac myocytes.

We have previously described detailed procedures for isolating rat and canine myocytes from adult ventricular tissue, and have investigated ultrastructural and functional properties of these cells. The effects of isolation on cell morphology were tested by comparative scanning (SEM) and transmission electron microscopy (TEM) of adult canine cardiac myocytes. Cells cleanly separated at the lateral sarcolemmal borders and at the intercalated discs. Since the cells were contracted during fixation, SEM of the lateral cell borders showed longitudinal folds and transverse ridges. There were rows of regular protrusions corresponding to the mitochondria immediately beneath the sarcolemmal surface. Openings in the sarcolemmal membrane occurred at regular intervals at the level of the Z-bands and may represent the sites of externalization of the transverse tubular system. By SEM, the intercalated disc junction appeared as a microvillar border and this corresponded directly to the scalloped appearance seen by TEM. A controlled sonication procedure was developed to allow specific removal of the sarcolemma without disruption of underlying organelles. This allowed visualization of the cellular organization of myofibrils, mitochondria and the transverse tubular system. These cells retain biochemical and enzymatic characteristics of adult dog cardiac tissues such as ouabain and insulin sensitivity, fatty acid and lipoprotein uptake and metabolism, and prostaglandin synthesis. This cytological preparation permits the correlation of these types of metabolic studies with the known functions of isolated subcellular organelles of the myocardium.

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PubMed1978

Pyridinolcarbamate and experimental atherosclerosis. Correlation of hypocholesterolemic and antiatherogenic effects.

Rabbits were maintained for 12 weeks on either a control or hypercholesteremic dietary regime, or on comparable diets supplemented with pyridinolcarbamate (PDC) at a level of 30 mg/kg body weight/day. Blood was obtained from all rabbits prior to study and at two-week intervals for analysis of serum cholesterol, phospholipid phosphorus and triglycerides. Animals from each group were sacrificed at 4-week intervals for quantitative assessment of the degree of atherosclerotic involvement of the aorta. All animals in the four groups consumed their entire daily allowance (100 g) of their respective diets, and weight gains throughout the feeding period were comparable in the 4 groups. PDC given with the control chow diet had no effect on serum cholesterol levels but did result in persistent decrease in serum triglycerides and a variable decrease in serum phospholipids during the 12-week feeding period. None of the rabbits on the chow diet, with or without PDC, had any evidence of aortic lesions during the experimental period. Rabbits fed 1% cholesterol administered with chow exhibited markedly elevated levels of serum cholesterol and phospholipids, while serum triglycerides were not significantly different than in the control group. In these animals there was a rapid and progressive increase in aortic atherosclerosis throughout the study, and at 12 weeks plaque involvement was 74 +/- 8% of the aortic surface. Addition of PDC to the 1% cholesterol--chow diet resulted in significantly lowered levels of serum cholesterol and phospholipids, but these remained elevated compared to the control levels. There was also a dramatic reduction in the rate and extent of aortic plaque formation. Thus, after 12 weeks on diet, only 27 +/- 6% of the aortic surface showed evidence of atheroma. The data suggest that PDC significantly decreases the hypercholesteremia resulting from feeding 1% cholesterol to rabbits, and that this may be largely responsible for the antiatherogenic effect of this drug.

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PubMed1976

Surface morphology of human aorta as revealed by the scanning electron microscope.

Human aorta was prepared for scanning electron microscopy using critical point drying. The aortic surface is lined by a continuous layer of squamous endothelial cells. The luminal surface of these cells contains many microvilli or microappendages and pinocytotic vesicles. In addition, at the periphery of each cell, larger marginal appendages or microfolds are present which allow the observer to see the cell boundaries clearly. The marginal folds are superficial to the cell junctions and could be observed without any staining procedures. These observations on human aorta are generally in agreement with our findings on the rabbit and guinea pig aorta and vena cava but in contrast to others who have reported the presence of ridges, intercellular bridges, and "hair-like" processes on the endothelial surfaces.

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PubMed1976

Electron microscopic studies of estrogen-induced ciliogenesis and secretion in uterine tube of the gilt.

The time required for occurrence of estrogen-induced uterine tubal (oviductal) ciliogenesis and for differentiation of secretory cells was studied, utilizing electron microscopy procedures. Sixteen cycling gilts were ovariectomized; 3 to 4 months later, 12 principal gilts were each given subcutaneous injections of 17 beta-estradiol in 0.5 ml of corn oil at the rate of 200 mug/day, and 4 control gilts were given injections of corn oil only at the rate of 0.5 ml/day. Two principals each were killed on days 1, 2, 3, 4, 5, and 7 after start of treatment. The epithelial heights were low and completely atrophied 3 to 4 months after ovariectomy. Uterine tubal cilia were absent in all the control gilts. Cytologic changes were not seen in the atrophied epithelium of ovariectomized gilts 1 day after estradiol treatment, but definite proliferative elements consisting of an extensive fibrillar meshwork encrusted with granules (60 to 80 nm) were observed in close association with the nuclear envelope and in the apical cytoplasm after 2 days of estradiol treatment. By day 3, enlarged electron-opaque granules referred to as condensation forms, undergoing various stages of depletion, were closely associated with radially arranged procentrioles. These associations have been referred to as generative complexes. The presence of many generative complexes indicates that maximal production of basal bodies can be expected after 3 days of treatment with estradiol. The depletion of the condensation forms produced hollow spheres with thin walls as the procentrioles grew in length and assembled their microtubules. Enlarged mature-appearing basal bodies were abundant in the cytoplasm after 3 days of estradiol treatment. These bodies aligned themselves linearly along the luminal surface of the cell. Small ciliary buds were then formed above the cell surface, and ciliary filamentogenesis occurred in the bud. Motile cilia were observed on day 3, but cilia numbers increased markedly between day 4 and days 5 and 7. Procentrioles were generated from the diplosomal centriole after 2 days of estradiol treatment. These observations have provided evidence for both ancentriolar and centriolar basal body replication in the ciliated cells of uterine tube of the gilt. Maximal secretory cell differentiation occurred after 3 days of estradiol treatment. Hypertrophy of cytoplasmic organelles was evident on day 3, but the number of secretory granules and amount of rough endoplasmic reticulum increased markedly on days 5 and 7. Close association of secretory granules, Golgi apparatus, and endoplasmic reticulum was evident after estadiol treatment. These data indicate that both ciliated and secretory cells are sensitive to estrogen.

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PubMed1976

Ultrastructural studies of prepubertal porcine uterine tube epithelium.

Ultrastructural details of prepubertal porcine uterine tube (oviduct) were studied in normal, growing gilts and compared with observations reported in other species. Tissues from the ampulla region of uterine tube were taken from 6 prepubertal gilts (106 to 139 days old) to determine cytodifferentiation of ciliated and secretory cells. The epithelium consisted of 2 distinctive cells, the ciliated and the secretory cells. Cilia were observed in the uterine tube of prepubertal gilts; however, degeneration of cilia was not observed in the present study. Most prominent observations were the occurrence of fibrous granules in the apical cytoplasm of ciliated cells. These fibrous granules contained electron-dense material and were present near basal bodies. The most unusual feature was the occurrence of procentrioles around a condensation form. These data indicate that ciliated cells are sensitive to estrogen. Intimate morphologic association between fibrous granules and basal bodies indicate that fibrous granules might provide precursor material for the development of cilia and rootlets. The cytoplasm of the secretory cells contained rough endoplasmic reticulum of tubular form and numerous ribosomes. Evidence for synthesis, storage, and release of secretory granules was not apparent. It is suggested that the secretory cells are not sensitive to the low, circulating concentration of plasma estrogen. The ultrastructure of the stromal cells and lymphatic capillary was described for the 1st time. The uterine tube stromal cells were characterized by prominent nucleus and a few cytoplasmic organelles. The lymphatic capillaries were distinguished by the blood capillaries, their much wider lumen, endothelium with an attenuated cytoplasm, absence of basal lamina, and overlapping and interdigitating intercellular junctions. The fine structure of the porcine uterine tube lymphatic capillary generally resembled that of other mammalian species.

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PubMed1976

Cyclic ultrastructural changes in ewe uterine tube (oviduct) infundibular epithelium.

Ultrastructural features of the uterine tube (oviduct) infundibulum of ewes have been studied, with special reference to cyclic changes in the ciliated and the secretory cells. Tissue from the uterine tube infundibulum was taken from 12 Rambouillet crossbreed ewes which were killed at intervals (days 1 (or estrus), 3, 9, 10, 12, and 16) throughout the estrous cycle. The presence of cilia was demonstrated throughout the estrous cycle, and true degeneration or loss of cilia was not apparent at any phase of the cycle. Presence of fibrous granules, which are supposedly related to basal body replication, was demonstrated in the apical cytoplasm of ciliated cells on day 1 of the estrous cycle. Small ciliary buds were especially present on day 1, indicating active formation of cilia during the follicular phase of the cycle. The presence of fibrous granules, basal bodies, and ciliary buds at estrus indicates that ciliogenesis in the ewe uterine tube is stimulated by high levels of endogenous estrogen. Rootlets were observed both during the follicular and the luteal phases of the cycle. The rootlets were about 1 mum long, and their fine structure indicates that they might function as anchoring structures for the motile cilia. The most striking feature during estrus was the occurrence of glycogen granules in the cytoplasm of ciliated and secretory cells. These granules were in the apical cytoplasm and basal region of some epithelial cells. They were minimal or absent during the luteal phase of the estrous cycle. The presence of electron-dense glycogen particles was clearly demonstrated within basal bodies. Possibly the glycogen within the basal bodies functions as a source of energy for ciliary movement and the cytoplasmic glycogen as nourishment for the ovum. The secretory cells also showed characteristic cytologic changes which were correlated with the phase of the estrous cycle. Maximal secretory cell differentiation was apparent during the follicular phase, at which time these cells were characterized by well-developed rough endoplasmic reticulum, numerous ribosomes, and secretory granules of varied size, shape, and density. A most remarkable feature of the granules was their membranous structure, consisting of concentric lamellae of equal dimensions. Typical extrusion of secretory granules into the tubal lumen was apparent during the follicular and the luteal phases of the estrous cycle. Cytoplasmic projections containing nuclei protruded into the tubal lumen and some were free in the lumen, especially during the luteal phase of the estrous cycle. The presence of a well-developed endoplasmic reticulum and numerous secretory granules during estrus indicate that secretion in the ewe uterine tube is presumably under the control of circulating high plasma concentrations of estrogen.

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PubMed1976

Fine structural changes of the porcine uterine tube epithelium during early and late pregnancy.

Ultrastructural changes in the uterine tube (oviduct) of pregnant gilts have been investigated with special reference to the ciliated, secretory, and stromal cells. Tissue from the uterine tube ampulla and infundibulum was taken from 18 gilts at different stages of gestation (days 31, 36, 101, 102, 107, 110, and 112). Cilia were present throughout pregnancy, and deciliation was not apparent at any stage of gestation. The low epithelium of the uterine tube appeared similar to that of the luteal phase of the estrous cycle when corpora lutea were full grown. Prominent features at end of the gestation were numerous fibrous granules and basal bodies, indicating active formation of ciliary precursor organelles. Fibrogranular aggregates were also present in association with the basal bodies. In addition, numerous polyribosomes, mitochondria, and microtubules were encountered in the cytoplasm of ciliated cells at end of the gestation. The appearance of electron-opaque, fibrous granules during late pregnancy probably could be correlated with increasing endogenous levels of plasma estrogen. Intimate morphologic association between fibrous granules and basal bodies indicate that fibrous granules might provide precursor material for the development of cilia or rootlets. Characteristics ultrastructural changes observed in secretory cells during the estrous cycle were not discernible in secretory cells during pregnancy. The secretory cells appeared similar to those of the luteal phase of the estrous cycle. The apocrine secretory cells contained prominent, apical, cytoplasmic projections; pinching-off process of these protrusions was frequently observed during early and term gestation. Extruded nuclei along with other cytoplasmic organelles were also present, lying free in the tubal lumen. The endoplasmic reticulum was predominantly tubular in form. Synthesis, storage, and release of secretory granules were not apparent at early or late pregnancy. It is suggested that progesterone might have an inhibitory effect on the synthesis, storage, and release of secretory granules. Ultrastructural changes in stromal cells were not apparent at any stage of gestation. The stromal cells appeared similar to that of the luteal phase of the estrous cycle.

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PubMed1975

Electromagnetic field effects in nerve tissue.

In the present work, an attempt has been made to produce structural alterations in tissue from the nervous system of bullfrogs by means of a high-intensity electric field. The electric field used to expose the tissue was compased of a train of high-intensity, short-duration pulses. Theses pulses provide a high electric-field intensity in the tissue, yet a low enough absorbed-energy density to cause negligible thermal heating. Exposed and control tissue prepared for light microscope investigation was stained with thionin and hematoxylin and eosin stains. No gross histological alterations of the large motor neurons of the exposed tissue were found when compared with the control tissue.

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