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Biomedical subjects

L J Didio

Publications and source records attributed to L J Didio.

At least 19 recordsLinked to original sources
PubMed1994

Ductal budding and branching patterns in the developing prostate.

Development of the prostate was studied by serial section reconstruction and computer-assisted three-dimensional analysis. A comparison of ductal budding in species of rat and mouse and the human revealed patterns consistent with common developmental characteristics. Ventral, lateral and dorsal lines of epithelial buds, which emanated from the urogenital sinus into the surrounding periurethral mesenchyme, followed ventro-dorsal and cranio-caudal axes. Subsequent branching morphogenesis was associated with specific mesenchymal condensations. These patterns of budding were closely related to the adult lobe architecture in the rodent prostate. In the human fetus, prostate ductal budding exhibited patterns compatible with the current concept of zonal anatomy.

Animals↗
PubMed1993

Cellular and subcellular alterations of the thyroid gland in rats caused by lithium carbonate.

Biochemical, hematologic, histometric, structural and ultrastructural changes were studied in the thyroid gland of rats, whom were administered Lithium carbonate. It was noted that (1) the Li carbonate had a cumulative effect on the serum; (2) T3 and T4 hormones in the blood decreased throughout the experiment; (3) the red blood cells, hemoglobin, hematocrit, platelets and leukocytes decreased gradually; (4) the diameter of the thyroid follicles, the size of the follicular cells and colloid droplets decreased, whereas the stroma was invaded by a greater number of collagen fibers and blood capillaries.

Animals↗
PubMed1993

Subcellular organization of the placenta in the Atlantic sharpnose shark, Rhizoprionodon terraenovae.

The Atlantic sharpnose shark, Rhizoprionodon terraenovae, is a viviparous anamniote that develops a yolk sac placenta composed of: a) uterine mucosa, b) egg envelope and c) fetal yolk sac mucosa. The transporting uterine mucosa is a squamous epithelial bilayer with prominent lateral and basal infoldings between contiguous cells. The surface cells have prominent secretion vesicles that empty their contents to the exterior. Immediately beneath the epithelium is a basal lamina and a profuse vascular supply with a continuous endothelium. The epithelium of paraplacental uterine sites is mucous. The tertiary egg envelope is retained throughout gestation and separates the distal part of the yolk sac from the maternal uterine mucosa. The egg envelope is compact on the yolk sac surface but displays delaminations on the uterine surface. The fetal yolk sac is composed of two portions, viz., a proximal, saccular region and a heavily vascularized, rugose, distal portion. The proximal portion has ultrastructural characteristics of a steroid hormone producing tissue, including massive smooth endoplasmic reticulum frequently forming whorled arrays. However, definitive evidence that the yolk sac is an endocrine organ is lacking. The distal portion of the fetal yolk sac is composed of a squamous epithelial bilayer that is separated from the underlying vascular network by a continuous basal lamina. The endothelium of the vessels is fenestrated. Cytoplasmic characteristics of these cells include an extensive Golgi complex, smooth walled caveolae, vesicles with electron-dense contents that are presumably endocytotic in nature and dense bodies that are suggested to be lysosomes that are involved in the digestion of material that may be yolk metabolites.

Amnion↗
PubMed1993

Fine structure of the term umbilical cord in the Atlantic sharpnose shark, Rhizoprionodon terraenovae.

The fine structure of the umbilical cord and appendiculae in the Atlantic sharpnose shark, Rhizoprionodon terraenovae, is examined by light, scanning and transmission electron microscopy. During ontogeny of placental sharks, the yolk sac and stalk become progressively modified as a functional hematrophic placenta and umbilical cord respectively. In most placental sharks the umbilical cord is smooth. In the Atlantic sharpnose shark, the epithelial ectoderm of the somatopleure forms richly vascularized extensions termed appendiculae. Scanning electron microscopy reveals that the base and shaft of appendiculae are flattened while the distal portion may be expanded to form one to three lobes. The surface of appendiculae is composed of two distinct cell types, the most plentiful are microvillar cells. The second cell type contains prominent granules. These cells are much larger than the former and are partially submerged below the surface, except for the cell apex. These cells undergo secretory cycles ending in expulsion of their contents. The possible function of the granulated cells is discussed. The umbilical cord contains an umbilical vein, umbilical artery, ductus vitellointestinalis and extraembryonic coelom. The endodermal ductus initially conveys yolk from the yolk sac to the fetal gut by activity of ciliated cells lining it. The ductus persists in the adult. Microvillar cells, also present in the ductus, may play a role in the absorption of yolk metabolites early in development, prior to yolk depletion. Enteroendocrine cells are wedged between the ciliated and microvillar cells. These cells may exert paracrine regulation of local areas of the ductus.

Animals↗
PubMed1993

Subcellular alterations of cardiac fibers in rats subjected to hypothyroidism.

Subcellular changes of the atrial cardiomyocytes of rats submitted to hypothyroidism caused by administration of 1 mg/100 g of body weight of propylthiouracil showed a) swollen mitochondria and lysis of their cristae; b) myofibrils with marked heterogeneity of patterns, some exhibiting rupture and loss of continuity of their myofilaments; c) lesser concentration of atrial granules in the perinuclear area; d) abundant granular interstitial tissue and collagen separating the myofibrils.

Animals↗
PubMed1992

Variations of the blood supply of the human conus arteriosus.

The conus arteriosus was divided into right and left halves and each half was subdivided into 3 portions: superior, middle and inferior. The study of the blood supply of the conus was performed in 8O human hearts. The results showed that the sternocostal wall of the conus arteriosus may be supplied by the arteria coni arteriosi but, more frequently by branches of the right and left coronary arteries. The most frequent branches supplying the conus arteriosus were the ramus anterior ventriculi dextri medialis and lateralis (85%), ramus coni arteriosi dexter (51.2%), ramus anterior ventriculi dextri medius I (47.5%), ramus anterior ventriculi dextri intermedius (41.2%), ramus coni arteriosi sinister (40%) and ramus anterior ventriculi dextri superior I (38.7%).

Adolescent↗
PubMed1990

Subcellular changes of rat myocardium after treatment with amiodarone or desethylamiodarone, studied with electron microscopy.

Amiodarone, an antiarrhythmic agent, has proven to be unique in its capability to control arrhythmias unresponsive to conventional drugs. However, its association with many undesirable side effects after chronic usage has become just as clear. Chronic clinical toxicity with amiodarone is associated with intracellular lamellar or myelinoid inclusion bodies (onionoid bodies or corpora cepiformia) in various organs (i.e. skin, cornea, lung, liver, and lymph nodes). Previous study has demonstrated formation of these inclusion bodies in canine myocardium following multiple doses of amiodarone. The present study was designed to develop a more convenient animal model, and to measure the concentration of amiodarone, as well as desethylamiodarone (its major metabolite) in this rodent model. The direct role of desethylamiodarone in formation of lamellar inclusion bodies in rat myocardium was also investigated. Amiodarone (50 mg/kg) or desethylamiodarone (25 mg/kg) was injected intraperitoneally daily for a period of 14 days. Myocardial sections revealed the presence of lamellar inclusion bodies, round or oval in appearance, in the form of laminated or concentrically arranged membranes after either amiodarone or desethylamiodarone treatment. This is the first reference to the induction of these myelinoid inclusion bodies with desethylamiodarone. Myocardial tissue concentrations of amiodarone and desethylamiodarone exceeding plasma concentrations were found in the present study and indicate the capability of these compounds to easily distribute and accumulate in the myocardium.

Amiodarone↗
PubMed1988

The prostate in pregnant and non-pregnant Praomys (Mastomys) Natalensis at the subcellular level.

The prostate of the pregnant Praomys appears more active than that of the non-pregnant Praomys. At the light microscopic level, the most obvious features are heightening of secretory cells and increased secretory product in acinar lumina. Apparent at the electron microscopic level are an increase and dilation of the rough endoplasmic reticulum, numerous scattered secretion granules, and a dilated Golgi apparatus. Therefore, stimulation of the gland is evident upon cytological evaluation and this increased activity may be due to the direct or indirect effects of androgenic stimulation.

Animals↗
PubMed1987

Endocrine cardiomyocytes.

A short review of the history related to the identification and classification of cardiac hormones shows that long before the development of modern scientific technology these substances had been predicted. It is an outstanding example of how meticulous observation, even with simple instruments, coupled with creative imagination, sound logic, and far reaching vision, may bring about marvelous accomplishments. The fast changing field and numerous contributions are responsible for the unsettled nomenclature and not completely settled concepts of the heart as a pump and as an endocrine organ. Although the bulk of knowledge amassed prior to the advent of the electron microscope is amazing, it was, however, only after the biological application of electron microscopy that the morphological evidence of the cardiac elements responsible for the endocrine function of the heart could have been provided. As usual, although not always the case, it was the anatomical, specifically the subcellular, description of the endocrine cardiomyocytes that caused the recent extraordinary advances in the recognition of another function of the heart. In a broad sense, the extension of internal secretion and its subcellular morphological background to other structures allow one to add endocrinosity as a general principle of construction and function of the human body. Our selective, obviously incomplete review, may not include publications that a different subjective approach might have included. While the Authors count on the indulgence of the readers, they emphasize that what is missing is not necessarily less important. The main aims of this publication have been to concentrate on early historical developments and to be able to repeat, once again, how much the mind can accomplish, even without the wonders of modern technology. Once the latter is made available, however, it obliges scientists to use their ingenuity at a higher level, providing the scientific and technological revolutions that occur from time-to-time. The recent history of medicine is replete with such events, which have proven so beneficial for mankind.

Animals↗
PubMed1987

Comparative morphology of the prostate in adult male and female Praomys (Mastomys) Natalensis studied with electron microscopy.

Comparative study at the cellular and subcellular levels of the adult male and female prostates of a unique species of rodent--Praomys (Mastomys) Natalensis--was made. The female possesses a well-developed prostate throughout life that may be considered homologous to the ventral prostatic lobe in the male Praomys. Histologically, only small differences exist to indicate that the female prostate is somewhat less active than the male (less secretion and the presence of fewer supranuclear light areas in the female than in the male prostate). At the electron microscopic level, within the female prostatic cells, there is less rough endoplasmic reticulum, and the number of secretory granules is lower than in the male. The arrangement of the cells, the organization of the subcellular structures, and the mode of secretion in both female and male prostates, however, are similar.

Animals↗
PubMed1986

Amiodarone-associated changes in human neutrophils.

Amiodarone and its major metabolite, desethylamiodarone, were measured in the plasma, white blood cells (WBCs) and red blood cells (RBCs) of 14 patients receiving chronic amiodarone therapy. The mean plasma concentrations (+/- standard error of the mean) of amiodarone and desethylamiodarone were 2.4 +/- 0.6 and 1.6 +/- 0.4 microgram/ml, respectively. The drug level in the WBCs was 62 +/- 12 micrograms/g protein during the early loading phase and 106 +/- 33 micrograms/g protein during maintenance phase of amiodarone therapy. Desethylamiodarone concentration in the WBCs was 42 +/- 18 and 190 +/- 33 micrograms/g protein during the loading and maintenance phases, respectively. Although a trend in WBC to plasma concentration was seen, there was no linear correlation between these levels. In 1 patient with severe neuropathy, biopsy of the nerve and muscle showed high concentrations of both amiodarone and desethylamiodarone. Although there was a decrease in tissue drug levels, proportionately high tissue:plasma drug levels were detected at the time of necropsy approximately 6.5 months after amiodarone was discontinued in this patient. Neutrophils from all patients receiving chronic amiodarone therapy showed multiple myelin-like polymorphic inclusion bodies (onionoid bodies) upon electron microscopic examination. Our observations suggest that WBC drug concentrations and electron microscopic changes may provide a means of correlating tissue concentrations and of following patients receiving chronic amiodarone therapy.

Amiodarone↗
PubMed1986

Light and electron microscopic study of the postnatal prostate in male Praomys (Mastomys) Natalensis.

The postnatal development of the prostate was studied in male Praomys (Mastomys) Natalensis using both light and electron microscopy. At birth, the ventral and dorsal lobes consist of cords of cells that previously budded from the urogenital epithelium into condensed pads of stroma. The ventral cords have developed small lumina, whereas lumina do not develop in the dorsal lobe until two days after birth. The cords and tubules lengthen, branch, and coil so that by six days, the tubules of the ventral lobe almost completely make up the substance of the enlarged prostate, and those containing the larger lumina have only one to two cell layers surrounding them and contain a small amount of secretory product. The dorsal lobe, however, remains composed of small tubules. The ventral prostatic acini of the 12 day animal develop epithelial infoldings, the lining cells increase in height, and many acquire supranuclear light areas. The dorsal lobe acini remain smaller than those of the ventral lobe and are lined by cuboidal cells. Their secretion is evident at 18 days. By one month, the ventral and dorsal prostates of the male Praomys appear similar to those of the adult. Thereafter, changes include increase in size, acinus number and size, and epithelial involutions as well as the development of more prominent supranuclear light areas in the ventral prostatic epithelial cells.

Aging↗
PubMed1986

Comparative electron microscopic study of bovine, porcine and human parietal pericardium, as materials for cardiac valve bioprostheses.

Light, scanning and transmission electron microscopy were used in the comparison of bovine, porcine and human parietal pericardium. Bovine pericardium is widely used for heart valve bioprosthesis, is thicker than the other two, and has more coarse connective tissue fiber components, whereas porcine pericardium possesses relatively larger quantities of fat cells in regular layers. Human tissue is thinner than either the bovine or porcine parietal pericardium and its mesothelium seems less delicate. The human tissue, being thinner, may provide a source of materials for valves with significant hemodynamic characteristics. Such material might be used to produce small diameter valves directed towards younger patients. Though the literature does not mention its usage, porcine pericardium is of intermediate thickness and it too may serve in the future as a construction material for valve bioprostheses.

Adipose Tissue↗
PubMed1985

Permeability of external gill filaments in the embryonic shark. Electron microscopic observations using horseradish peroxidase as a macromolecular tracer.

External gill filaments of sharks are purely transient embryonic structures. They contain a single vascular sinusoidal loop that is continuous with the afferent and efferent branchial arteries. Each filament is comprised of a squamous epithelial bilayer that rests upon a prominent basal lamina. A collagenous stroma separates the epithelium from the underlying endothelium. The epithelium, from an embryo 4.5 cm in total length, is characterized by microvilli with smooth walled vesicles at their bases, a luminal glycocalyx, prominent tubular and vesicular elements, rough endoplasmic reticulum, a Golgi complex, a flattened nucleus, coated vesicles, lipid-like inclusion bodies and sparse cytoplasmic fibrils. Adjacent epithelial cells are joined by a zonula occludens, a zonula adherens and up to five maculae adherentes. The endothelium possesses mitochondria, rough endoplasmic reticulum, a Golgi complex, coated vesicles and many micropinocytotic vesicles on both the adluminal and abluminal surfaces. The endothelium has no basal lamina and is not associated with smooth muscle. After exposure to horseradish peroxidase (HRP) for 10 min, reaction product nearly occludes the cytoplasm of some surface epithelial cells. The deeper epithelial cells have reaction product in smooth walled vesicular and tubular elements. Reaction product is also present in smooth walled endothelial vesicles. Gill filaments from a 10 cm embryo show marked changes from earlier stages. In the epithelial cells, there is an increase in the number of cytoplasmic filaments and the formation of a dense terminal web. Fewer vesicles, tubules, rough endoplasmic reticulum and mitochondria, and a less elaborate Golgi complex characterize the epithelium. The endothelium remains unchanged. The amount of collagen increases and fibroblasts are observed in the stroma. These modifications contribute to the strength of the filaments and allow the gills to withstand increased abrasion by the developing skin denticles. These experiments establish the capability of external gill filaments to take up a macromolecular tracer in the form of horseradish peroxidase. Later in development, the yolk sac of R. terraenovae becomes modified as a yolk sac placenta which functions both in respiration and hematrophic nutrition. In viviparous sharks, the uterus elaborates nutrient-rich secretions. External gill filaments may thus serve as a nutrient absorptive membrane before the establishment of the yolk sac placenta as well as perform its respiratory function.

Animals↗
PubMed1983

Morphological alterations in dura mater encephali used as ventricular wall grafts in the canine heart.

Structural changes within homologous dura mater patch-grafts surgically implanted in the right ventricular wall of the heart were studied in nine adult dogs utilizing light microscopy and transmission and scanning electron microscopy. Physical examination of the dogs after surgery presented no clinical signs of abnormalities caused by either the surgery or the nature of the graft. After one week of implantation, a fibrous organization extending from the wound margins over the entire graft greatly increased its thickness. In addition, it was observed that (1) an increase in cellularity, vascularity and connective tissue elements occurred on the external surface of the patch-graft, (2) these same changes occurred regardless of which surface (periosteal or arachnoidal) was used as the external or pericardial surface, (3) the graft core underwent a transition from a relatively acellular and avascular connective tissue structure into one that was heavily infiltrated by a variety of cellular elements and new blood vessels, and (4) these morphological changes were interpreted as an attempt to incorporate the graft into the host tissue, resulting in an increase in both viability and stability of the graft. These findings indicate that homologous dura mater is a suitable material for use in the surgical repair of the cardiac wall.

Animals↗