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PubMed1985

The ultrastructural features of secretory cells of some endocrine glands in aging.

In the electron microscopic investigation of the secretory cells of adenohypophysis, adrenal cortex, adrenal medulla and pancreatic islets from the adult and old Wistar male rats, certain age-related ultrastructural features have been found. Age changes appeared to be more pronounced in the thyrotrophs, somatotrophs and gonadotrophs of the adenohypophysis and in zona glomerulosa and zona reticularis spongiocytes of the adrenal cortex. They consisted of atrophy of the Golgi apparatus, appearance of the cytoplasmic vacuoles, lipid and lipofuscin granules, secondary lysosomes and damage of the inner mitochondrial membrane. Parallel to these, hypertrophy of the Golgi apparatus and rough endoplasmic reticulum, formation of giant mitochondria and presence of a great number of secretory cells in the cellular cytoplasm were noted in zona fasciculata spongiocytes and chromaffin cells of the adrenal medulla, and in beta cells of the pancreatic islets during aging thus evidencing for the adaptive changes in the ultrastructure of these cells. However, no appreciable age changes have been observed in the ultrastructure of the adrenocorticotropic cells of the adenohypophysis.

Adrenal Glands↗
PubMed1995

The effect of the treatment of high-dose methylprednisolone on Na(+)-K(+)/Mg(+2) ATPase activity and lipid peroxidation and ultrastructural findings following cerebral contusion in rat.

BACKGROUND: Although use of corticosteroid in the management of head trauma has caused a great deal of controversy, corticosteroids have long been an adjunct in the management of severe closed head injury. The glucocorticoid steroid methylprednisolone (MP) has been proven to have significant antioxidant effect when administered in an antioxidant-high dose after central nervous system injury. METHODS: The sodium-potassium activated and magnesium dependent adenosine-5'-triphosphatase (Na(+)-K(+)/Mg(+2) ATPase EC.3.6.1.3.) activity, lipid peroxidation, and early ultrastructural findings were determined during the immediate posttraumatic period in rats. Mechanical brain injury was produced when a calibrated weight-drop device is allowed to fall on the skull's convexity over the right hemisphere, 1 to 2 mm lateral from the midline. In group I, rats were used to determine Na(+)-K(+)/Mg(+2) ATPase activity, the extent of lipid peroxidation, by measuring the level of malondialdehyde content and normal ultrastructural findings in two different brain areas (cerebral cortex and brain stem). In group II, physiologic saline was administered right after trauma in the same amount as methylprednisolone. In group III rats, methylprednisolone (30 mg/kg) was administered intravenously right after trauma. RESULTS: Na(+)-K(+)/Mg(+2) ATPase activity significantly decreased in the cerebral cortex and in brain stem within 2 hours after trauma (p < 0.05). There was significant difference in malondialdehyde content between groups II and III (p < 0.05). Methylprednisolone treatment reduced malondialdehyde content and induced the recovery of Na(+)-K(+)/Mg(+2) activity. CONCLUSIONS: These data suggest that inactivation of Na(+)-K(+)/Mg(+2) ATPase is closely correlated to changes of lipid peroxidation and the alteration of the ultrastructural findings in the early phases after head trauma. The glucocorticoid steroid methylprednisolone has been proven to have significant effect in activation of Na(+)-K(+)/Mg(+2) ATPase with significant reduction of malondialdehyde content.

Animals↗
PubMed1984

An ultrastructural comparison of grade I and II endometrial adenocarcinoma considering estrogen and progesterone receptor status.

Eighteen (18) previously untreated patients with grade I (9) and II (9) endometrial adenocarcinoma provided endometrial samples for biochemical analysis of estrogen and progesterone receptors. The same samples were evaluated by histology and ultrastructure. Progesterone receptor negative samples (PR less than 1000 fmole/g tissue) showed more ultrastructural characteristics of malignancy and a wider range of changes than the progesterone positive specimens (PR greater than 1000 fmole/g tissue). These findings appeared to be independent of estrogen receptor status. No significant ultrastructural changes were seen when grades I and II were compared.

Adenocarcinoma↗
PubMedDate not supplied

Respective effects of hindlimb suspension, confinement and spaceflight on myotendinous junction ultrastructure.

This study compares the effects of 14-day confinement and spaceflight with the respective effects of 8, 18 and 29-day hindlimb suspension on rat soleus and plantaris MTJ ultrastructure. Independently of the experimental situation, greater morphological changes were observed in the soleus as compared to the plantaris MTJ. 18 days of suspension and 14 days of confinement resulted in ultrastructural modifications of the digit-like processes in the soleus MTJ. Additional changes were observed in the myofibrils, microtendon and tendon after 29 days of suspension and 4 days of spaceflight. These results emphasize the influence of the intensity and duration of the muscle loading on the MTJ ultrastructure.

Animals↗
PubMed1995

Demonstration of a focused ion-beam cross-sectioning technique for ultrastructural examination of resin-dentin interfaces.

OBJECTIVES: focused ion-beam (FIB) etching, commonly used as a cross-sectioning technique for failure analysis of semiconductor devices, has recently been applied to biological tissues to expose their ultrastructure for examination. It was the aim of this investigation to determine the practical utility of FIB to cross-section resin-dentin interfaces in order to morphologically evaluate the completeness of resin penetration into the exposed collagen scaffold at the resin-dentin bond interface. METHODS: Two representative commercially available dentin adhesive systems were bonded to mid-coronal dentin. After appropriate fixation and dehydration of the resin-bonded dentin samples, a scanned focused ion-beam of a few tens of nano-meters in diameter was used to cross=section the resin-dentin interface. Examination of the interfacial ultrastructure was accomplished using a field-emission SEM. RESULTS: Results indicate possible artifact production at the cross-sectioned interface, hiding its actual ultrastructure, probably due to a heat-effect with possible recrystallization. Further studies of FIB are needed to optimize its usefulness for resin-dentin interface examinations and other biological tissue applications. SIGNIFICANCE: Complete resin saturation of the demineralized dentin surface-layer has been claimed to be the key factor for a long-lasting resin-dentin bond. A "clean" artifact-free micro-cross-sectioning technique may provide indisputable ultra-structural information about the depth of resin penetration into the demineralized zone. Such a test would be useful in the development of dentin adhesive systems.

Bisphenol A-Glycidyl Methacrylate↗
PubMedDate not supplied

Ultrastructural study of endothelial permeability to macromolecules in fetal paraplacental capillaries of European badger.

Permeability of the continuous placental capillaries to macromolecules has been studied in the hemophagous region of the badger placenta by perfusion in situ of cationized ferritin (CF) in three phases of gestation (days 10 to 22, 22 to 30, and 30 to 40 after ovo-implantation). This ultrastructural tracer mapped luminal microdomains; such fixation on the luminal cell membrane was a preliminary step before its internalization into the cytoplasm. Lateral intercellular spaces (LIS) and vesicles were found to play an evolving role during gestation. Ultrastructural maturation of the capillary may be related to evolution of endothelial permeability. The LIS are involved in the transport of this macromolecule during the first two-thirds of pregnancy, and become progressively impermeable to the tracer as true, tight junctions are established between the adjacent endothelial cells. The enlargement of the vesicular population in luminal, cytoplasmic and abluminal positions and the increase in microfilaments could make vesicular transport more efficient in favouring cellular contractility. These ultrastructural findings that indicate that the optimal endothelial permeability to CF occurs during the second phase of pregnancy when the paraplacental hematoma reaches its maximal development and functional activity.

Animals↗
PubMed1995

Ultrastructural investigation of circulating villous lymphoid cells: a tool in the differential diagnosis of splenic lymphoma with villous lymphocytes.

Ultrastructural examination of circulating lymphoid cells was performed in three cases of splenic lymphoma with circulating lymphocytes (SLVL) in order to define morphological features helpful to distinguish this lymphoma from hairy cell leukemia (HCL). The samples for ultrastructural investigation were obtained by Ficoll sedimentation from peripheral blood and routinely processed for electron microscopy. The ultrastructural features examined were: morphology of villi, morphology of nuclei, presence of nucleoli, distribution of heterochromatin, type of cytoplasmic organelles, presence of specific intracytoplasmic structures such as the ribosome-lamella complex, lysosome-like bodies and perinuclear microfibrils. Our results and a careful review of the literature seemed to confirm that SLVL has electron microscopic features typical enough to be relevant in the differential diagnosis with HCL.

Adult↗
PubMed1984

The effect of atmospheric pollution on Vitis vinifera L. pollen ultrastructure under natural conditions.

The ultrastructural modification of pollen grains in Vitis vinifera L. variety and hybrids in areas of SO2 atmospheric pollution (the main polluting SO2 usually reaches 2.72 mg/m3), nitrogen oxide, and other gases derived from noniron metal processing factories have been studied. Strains 1001 and 1002, resistant varieties, do not undergo ultrastructural modifications. Neuburger and Issabelle, medium resistant ones, have a heterogeneity in ultrastructural organization from normal forms to forms having both wall covers as well as the main organelles changed.

Air Pollutants↗
PubMed1988

Ultrastructure in leaves of Fagus silvatica and Carpinus betulus individuals tolerant and susceptible to SO2 and heavy metal pollutants.

The ultrastructure characteristics of leaves during the development of cell organelles, in the "greening process" of spring, have been studied in pollutant-tolerant and susceptible individuals of beech (Fagus silvatica) and hornbeam (Carpinus betulus) in an area polluted with SO2 (the main pollutant may reach 0.06-2.72 mg/m3), heavy metals, and other gases discharged by non-iron metal processing factories. Leaves from tolerant beech and hornbeam individuals did not undergo ultrastructural changes compared to control leaves in an unpolluted area. The susceptible and very susceptible individuals of both species gradually undergo modification in organelle ultrastructure not only during the first steps of greening and momentary exposure to air pollution, but also as a result of long-term exposure to chronic pollution in the forest.

Air Pollutants↗
PubMed1989

Preservation of neuronal ultrastructure in hippocampal slices using rapid microwave-enhanced fixation.

The goal of this study was to obtain fixation as rapidly as possible and to achieve preservation of neuronal ultrastructure to a depth in hippocampal slices where electrophysiological responses are optimal. This study demonstrates that perfusion quality preservation of in vitro hippocampal slices can be achieved within seconds after removal from the incubation chamber by using microwave (MW)-enhanced immersion in mixed aldehydes. The optimal method was determined to be MW irradiation of the slice for 8-11 s, to a tissue temperature of 35-50 degrees C, during immersion in fixative containing 6% glutaraldehyde and 2% paraformaldehyde. Electron microscopy of these slices revealed ultrastructural preservation that was comparable to hippocampi from animals perfused with mixed aldehyde fixative containing 2.5% glutaraldehyde and 2% paraformaldehyde. Excellent ultrastructural preservation extended to 100-175 microns from the hippocampal slice surface after MW-enhanced fixation and therefore was much deeper than the 8-20 microns that can be obtained by rapid freezing. Hippocampal slices are routinely maintained in vitro for electrophysiological or pharmacological studies. This method of MW-enhanced fixation preserves tissue within seconds after removal from incubation, and should provide good preservation of the hippocampal anatomy that might be associated with in vitro physiology.

Aldehydes↗
PubMed1983

Long-term study of the ultrastructural changes of myocardium in patients undergoing cardiac surgery, with more than 10 years follow-up.

The myocardium from 44 patients undergoing open cardiac surgery was studied to determine if alterations demonstrable with the electron microscope could be related to prognosis. Planimetric methods were used to evaluate myofibrils, Golgi, mitochondria, myelin figures, other organelles, and intracellular space in order to achieve as objective a measurement as possible. Morphologic changes were graded and correlated with clinical findings and results after long-term follow-up. Factors evaluated in terms of survival included patient age, degree and extent of valvular disease, the presence of coronary artery disease, and degenerative changes of the myocardium as demonstrated ultrastructurally. Patients dying, of cardiac causes, within the first 5 years, had a higher ultrastructural grade than those surviving for more than 10 years. Statistical analysis, using stepwise regression methods, demonstrated a highly significant correlation (P less than 0.001) between cardiac ultrastructural integrity and prognosis. The addition of age to the prediction model was also significant (P less than 0.04), using the two variable models, EM grade and age were, similarly, highly significant (P less than 0.001).

Adult↗
PubMed1989

Radiation-induced changes in the ultrastructure and mechanical function of the rat heart.

A time sequence study was performed to study the early effects of radiation on the ultrastructure of the rat heart. Wistar rats were exposed to 20 Gy electron irradiation to a field including the heart and a third of the lung. The hearts were excised at varying time intervals (1 h-180 days), and the ultrastructure of perfusion-fixed subepicardium and subendocardium studied. Changes were observed in both myocytes and interstitium at all time intervals. The most pronounced change observed in the myocyte was that of intercalated disc damage which reached a peak at 30 days post-irradiation. Mitochondrial damage, characterized by swelling and fenestration in areas of myofibrillar contracture, was focal and relatively scarce. Swelling of the capillary endothelial cells and collapse of the capillaries were marked up to 60 days. Of significance was the observation that the damage to both myocytes and interstitium receded after 60 days and the hearts exhibited an almost normal ultrastructure from 100 to 180 days post-irradiation. Mechanical function of these hearts followed a similar pattern: maximal depression was observed 60 days after irradiation. Thereafter the work performance of these hearts improved significantly, almost reaching control levels after 180 days.

Animals↗
PubMed1996

Ultrastructure of equine morbillivirus.

The ultrastructure of the equine morbillivirus (EMV) which was implicated in the death of one human and fourteen horses in Queensland, Australia during September 1994 and a 36 year old man from Queensland in October 1995 is described. The ultrastructure of the virus and the intracellular virus-specific structures are characteristic for the family Paramyxoviridae. Cytoplasmic nucleocapsids were observed within the infected cells monolayers, endothelial cells (lung) of infected horses and the neurons within the brain of the 36 year old Queensland man. Aggregates of smaller nucleocapsid-like structures were also observed within the brain of the same man; these did not react with sera from recovered EMV-infected horses or from a recovered EMV-infected human. Co-examination of rinderpest virus (RPV), bovine parainfluenza-3 (BPIV-3), human respiratory virus (HRSV) and Sendai virus revealed that their envelope-associated surface projections are equivalent in length to the 15 nm spikes of EMV. EMV differed from these other viruses in that the majority of virions possessed surface projections of two distinct lengths (18 and 15 nm). Further ultrastructural examinations of plaque purified EMV revealed a small percentage of EM viruses possessed a mixed array of surface projections indicating that the 'double-fringed' (DF) particles may be the result of a post-translational modification(s).

Adult↗
PubMed1996

Resistance of diabetic rat hearts to Ca overload-related injury. Histochemical and ultrastructural study.

The enzymatic histochemical and ultrastructural alterations of the rat heart during development of streptozotocin (STZ) induced diabetic cardiomyopathy were studied. Moreover, the response of the isolated diabetic hearts to Ca overload-Ca paradox-was investigated. In the early stage of diabetes (1 week of diabetes), no apparent histochemical changes were observed but gentle alterations of the ultrastructure of the myocytes and particularly capillaries were found. Structural changes of the myocytes and microangiopathy accompanied by decreased activities of some enzymes (phosphorylase, various dehydrogenases, ATPase) progressed with time and were more pronounced late in diabetes (9 weeks). Ca paradox induced severe structural damage of the majority of cardiomyocytes and loss of the cellular integrity, and marked decrease in activities of all enzymes. However, in acute diabetic heart only partial Ca paradox was observed. It was manifested by transmural heterogeneity of structural and enzymatic histochemical changes. Evident preservation of the ultrastructure and enzyme activities of the myocardium was revealed in late stage (9 weeks) of diabetes. It can be concluded that diabetes results in prevention of the Ca overload in rat myocardium in vitro. Disturbances in coronary perfusion associated with microangiopathy as well as altered Ca handling and depressed heart function may account for delayed development of Ca paradox in diabetic heart.

Animals↗
PubMed1995

Exogenous protoporphyrin inhibits Hep G2 cell proliferation, increases the intracellular hydrogen peroxide concentration and causes ultrastructural alterations.

Ultrastructural hepatocellular abnormalities in early stages of erythropoietic protoporphyria lead to hepatobiliary changes that cause overt liver disease in 5-10% of patients, not infrequently progressing to fulminant hepatic failure. This cannot be attributed solely to protoporphyrin crystal deposition in the liver. Hepatic redox systems have therefore been postulated as an equivalent for the photoreaction of protoporphyrin. We studied the dark effects of protoporphyrin and hematoporphyrin on HL60 and Hep G2 cells. Cell proliferation and intracellular H2O2 concentrations were assessed and related to the ultrastructural morphology. The incubation with protoporphyrin and hematoporphyrin resulted in a dose- and time-dependent inhibition of proliferation indices of Hep G2 cells. Flow cytometric analyses of intracellular H2O2 concentrations demonstrated a dose-dependent increase in both cell lines upon incubation with protoporphyrin. Hep G2 cells displayed ultrastructural alteration of the endoplasmatic reticulum and plasma membranes. Also 'cell blebbing' occurred. We conclude that exogenous protoporphyrin increases the intracellular H2O2 concentration and exerts a cytotoxic dark effect. This may contribute to the liver injury observed in erythropoietic protoporphyria.

Carcinoma, Hepatocellular↗
PubMedDate not supplied

VIP inhibits histamine-induced ultrastructural changes related to acid secretion by parietal cells.

We have studied the in vitro effect of VIP and histamine on ultrastructure of the parietal cells in isolated guinea pig fundic glands. The morphological changes induced by histamine in the parietal cells can be compared to those observed after histamine stimulation in vivo or in vitro on gastric mucosa preparations. In contrast, VIP incubation did not produce the ultrastructural changes related to gastric acid secretion, in resting parietal cells. Pretreatment of the glands by VIP resulted in a remarkable suppression of the histamine effect, since the parietal cells assumed an almost resting state. The data (1) indicate that the parietal cells in isolated gastric glands of the guinea pig retain in vitro the capacity to undergo the ultrastructural changes that are related to acid secretion in vivo after histamine or cAMP and (2) suggest that VIP is an inhibitor of histamine-induced gastric acid secretion in the guinea pig. It is proposed that VIP could act directly on the parietal cell via cAMP-phosphodiesterase activation, or indirectly via gastric somatostatin and/or prostaglandin secretions, inhibiting the H2 receptor-cAMP system of the parietal cell.

Animals↗
PubMed1985

Human ameloblastomas in vitro: light microscopical and ultrastructural observations.

The light microscopical and ultrastructural morphology in vitro of one case each of human plexiform, follicular and acanthomatous ameloblastoma are described. Ultrastructural analysis of cultured tumour cells revealed that the main cell type growing in vitro displayed morphological features typical of columnar cells or preameloblast-like cells of ameloblastomas. Irrespective of histological type all cases showed indistinguishable in vitro light microscopical and ultrastructural morphology. These findings strongly suggest that the columnar cell type accounts for the main proliferative capacity of ameloblastomas in vitro and most likely also in vivo.

Adolescent↗
PubMed1984

Long clinostation influence on the ultrastructure of Funaria hygrometrica moss protonema cells.

Changes in the ultrastructure of protonema cells of Funaria hygrometrica, cultivated during 20 days on a horizontal clinostat (2 rev/min), were determined by the electron microscopy method. About 20% of the cells were almost identical to those in the control, 20% were destructive cells, and in 60% ultrastructure changes were observed. The heterogeneity of the reaction demonstrated the evidence of sensitive cells on the clinostation process. Changes affected the ultrastructure of plastids, wall of the cell, and the form of the nucleus as well. Starch disappeared from chloroplasts practically completely, thylakoids swelled, granas frequently disappeared from plastids. Peroxisomes number in cells increased appreciably, width of cell walls decreased by almost half their size. Ca(++)-binding sites were revealed in cytoplasma of cells. Electronocytochemical exposure of ATPases activity with the presence of Mg++ and Ca++ ions showed that Mg(2+)-ATPase activity localization in clinosted cells was not too different from the control, while Ca(2+)-ATPase location presented differences in plasemalemma and Ca-sites. These changes are perhaps connected with the membranes permeability breaking and affect the plant cells adaptation to the influence of hypogravitation.

Bryopsida↗