Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “Ultrastructure”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 1,567 records · Page 87Linked to original sources
PubMed2005

[Influence of Candida albicans on the motility and ultrastructure of human spermatozoa in vitro].

OBJECTIVE: To explore the influence of Candida albicans (Ca) on the motility and ultrastructure of human spermatozoa and its possible mechanism. METHODS: Semen samples obtained from 10 healthy volunteers by masturbation were prepared by the swim-up technique and sperm density to 40 x 10(6)/ml. The samples were then inoculated at 37 degrees C with different concentrations of a uropathogenic strain of Ca isolated from an outpatient, with initial fungi/spermatozoa ratios varying among 1:1 (Group A), 1:10 (Group B), 1:100 (Group C), 1:1000(Group D), and 1:10,000 (Group E). And Group F containing Ham's F-10 only was found as the negative control. Motion parameters were analysed by computer-aided sperm analyzer (CASA) at 0 hour, 1 hour, 2 hours and 4 hours respectively. Modalities of spermatozoa and possible adherence and/or agglutination were observed under the light microscope. Finally, all the samples were studied by transmission electron microscopy. RESULTS: Distinct adhesion of spermatozoa to Ca and agglutination were noticed. In all the motion parameters, progressive motility was affected most and dependent upon incubation time and bacterial concentration. Progressive motility showed a significant difference between Group A and the control (P < 0.01). With the prolongation of incubation time, other parameters were showing more and more differences. Analysis by electron microscopy revealed multiple ultrastructural damages. CONCLUSION: Ca significantly inhibits human sperm motility and decreases sperm viability in vitro. Its mechanism is possibly related to Ca's adhesion to human spermatozoa and the impairment inflicted by Ca to sperm ultrastructure.

Candida albicans↗
PubMed1992

[Ultrastructural changes in nucleoli during embryogenesis of Marsilea vestita].

The nucleoli of oospheres and young embryos of Marsilea vestita exhibited a typical ultrastructure with segregation into several compact nucleolus-like bodies and small granules of similar appearance. When embryos reached the 16 cell stage, the granules disappeared and the nucleolar-like bodies changed into classical nucleolar components. When the embryos were submitted to hypothermic shock, the nucleoli returned to the characteristic ultrastructure of the very young stages. In ageing oospheres the nucleus was full of very compact clumps. No detectable RNA synthesis occurred in the oospheres and young embryos, and the same phenomenon applied in ageing oospheres and after cold shock treatment. Transcriptional activity started with the 8-16 cell stage in the reference embryos. These results suggest that nucleolar ultrastructure is correlated with rRNA synthesis.

Cell Nucleolus↗
PubMed2004

[Sensomotor cortex ultrastructure in pubertal offspring of alcoholized male rats].

Neuron, astrocyte and capillary ultrastructure was studied in the sensomotor cortex of 3-month-old offspring of the alcoholized male rats that received 8 g of alcohol prepared as 50% solution per kg of body weight once daily for 4 weeks. In addition to the signs of delayed maturation of neuronal and glial cell processes, some cortical areas demonstrated the destructive changes in a certain portion of neurons and elements of compensatory-adaptive processes in the others. Membranous and myelin-like intranuclear inclusions and marked Golgi complex changes were the characteristic features of the damaged cortical neuronal population. Astrocyte swelling, capillary deformation with their ultrastructural changes, accumulation of atypical inclusions in pericapillary astrocyte processes result in deterioration of bilateral blood-neuronal exchange. Possible role of ischemia-hypoxia factor in long-term disturbances in sensomotor cortex ultrastructure in the offspring of alcoholized male rats is emphasized.

Alcoholism↗
PubMedDate not supplied

Acellular dermal tissue study: an ultrastructural evaluation of human and porcine derived tissues in a rat model.

The purpose of this study was to evaluate the host response of a human and a porcine derived acellular dermal tissue (ADT) implanted in the subcutaneous tissue of a rat model. Two subcutaneous pockets were surgically created along the dorsal midline of 25 rats (5 rats/group). The human ADT was placed superiorly and the porcine ADT, inferiorly. The animals were sacrificed at 07, 15, 30, 60 and 180 postoperative days (PO) and the ADTs and surrounding soft tissues were assessed for ultrastructural evaluation by transmission electron microscopy. The ultrastructural findings were similar in both materials. Normal collagen and elastic fibers bundles were observed during all experimental moments, as well as macrophages presenting cytoplasmic enlargements digesting cellular portions after 15 PO. From 30 until 180 PO, vacuolar structures filled with an amorphous, electron-transparent substance, were present inside and outside the fibroblasts. Both human and porcine ADT showed similar pattern of ultrastructural response when implanted in the subcutaneous tissue of rats. The porcine ADT appears as a good alternative to be used as a biomaterial.

Animals↗
PubMed2004

[Myocardial ultrastructural changes in rats following different levels of acute +Gz exposure].

OBJECTIVE: To observe the effects of different levels of acute +Gz exposure on myocardial ultrastructure of rats and provide experimental basis for further development of anti-G measures. METHOD: Twenty male Wistar rats were randomly divided into 4 groups (n=5): normal control group, +20 Gz group, +10 Gz group and +5 Gz group. Profile of the centrifuge +Gz exposure was trapezoidal, in which +20 Gz lasted for 30 s, +10 Gz for 1.5 min. +5 Gz exposure was repeated for 3 times with 30 min interval and each for 1.5 min. Myocardial tissue of left ventricle was sampled for transmission electron microscopy 5 h after exposure. RESULT: +20 Gz and +10 Gz exposure caused obvious edema of myocardial and endothelial cells, myofibril disorder and injuries of mitochondria and nucleus. Breaks of myocardial fiber, formation of contraction bands and rupture of mitochondria were also observed in +20 Gz group. In +5 Gz group, there was still slight edema of myocardial and endothelial cells, while organic changes of myocardial ultrastructure were not observed. CONCLUSION: High +Gz exposure can cause myocardial ultrastructural injury in rats. Slight reversible injured response can also be observed in myocardial cell after repeated moderate level of +Gz exposure. This indicates that attention should be paid to the study of the effect of high +Gz on heart in pilots.

Acceleration↗
PubMed2004

[Ultrastructural changes in cerebral cortex and cerebellar cortex of rats under simulated weightlessness].

OBJECTIVE: To study the ultrastructural changes in the cerebral cortex and cerebellar cortex of rats under simulated weightlessness and the possible mechanism. METHOD: The tail-suspended rats model (-30 degrees head down tilt) was adopted to simulate weightlessness in the experiment. The rats were suspended for 7 d, 14 d, 21 d, and 28 d, and then were perfused through the hearts. The specimens were drawn from the rats' cerebral cortex and cerebellar cortex for electron microscopy. RESULT: The results showed that under simulated weightlessness, the main changes in the neuron can be described as follows: swelling of mitochondria, endoplasmic reticulum and Golgi complex, even formation of big empty vesicles; reduction of number of synaptic vesicles in IV layer; increase corrugation of capillary lumen and thickening of basement membrane. Degranulation of rough endoplasmic reticulum in Purkinje's cells of the cerebellar cortex occurred obviously. On the 14th and the 21st day of suspension, the changes were most significant and tended to return to normal on the 28th day. CONCLUSION: The experimental results demonstrated that simulated weightlessness led to ultrastructural changes in the cerebral cortex and cerebella cortex of rats. The ultrastructure changed with the course of simulated weightlessness and tended to return to normal. It showed an adaption to the simulated weightlessness.

Adaptation, Physiological↗
PubMed2005

[Comparison of retinal morphology and ultrastructure in defocus-induced myopia and form-deprivation myopia in rhesus monkeys].

OBJECTIVE: To investigate the changes of retinal ultrastructure of defocus-induced myopia and form-deprivation myopia in infant rhesus monkeys. METHODS: A -3.00 D spectacle lens (n = 9) or diffuser lens (n = 6) was worn over one eye and a zero-powered lens over the fellow eye in 15 healthy rhesus monkeys ranging in age from 1 to 1.5 months. The eyes were examined periodically with corneal topography, cycloplegic retinoscopy, A-scan ultrasonography, and optical coherence tomography (OCT). Three months later, light and electron microscope were used to observe the changes of the retina. RESULTS: In 15 monkeys, all eyes treated with -3.00 D spectacle lens or diffuser lens developed defocus-induced myopia or form-deprivation myopia. Not only defocus-induced myopia, but also form-deprivation myopia showed elongation of rod outer segment, decreased membrane disc of cone outer segment, increased clearance of the membrane disc and decreased thickness of the neurosensory retina (RNL) as compared with the control eyes (P < 0.05). There were no significant differences between the mean OCT and histomorphometric thickness of RNL and retinal pigment epithelium (RPE) after the correction of dehydration (P > 0.05). CONCLUSIONS: There are significant differences in retinal ultrastructure between experimental myopic eyes and control eyes. But the morphological changes in the retina of the defocus-induced myopia showed no significant difference as compared with form-deprivation myopia. The role of changes of retinal ultrastructure in the development of myopia needs further studies. OCT can be used to examine the changes of RNL and RPE in experimental myopia in vivo.

Animals↗
PubMedDate not supplied

The Kupffer cells. Ultrastructural and functional features.

The Kupffer cells, as fixed macrophages, belong to the mononuclear phagocyte system (MPS), the former reticulo-endothelial system (RES). Their ultrastructure has some characteristics, i.e. ergastroplasmic peroxidase activity and worm-like structures, which allow a very sharp identification. Some particular "bridge-like" arrangements of Kupffer cells in the capillary lumen seem to provide them with a special ability of "trapping" the passing white blood cells. The important endocytotic function is analysed from the viewpoint of ultrastructural features, and with particular reference to the phagocytosis of damaged red blood cells. Several drugs and particulate substances acting as Kupffer cells stimulants are presented. This stimulation reaction concerns woth increased number and enhanced endocytotic activity. The origin and kinetics of Kupffer cells are discussed, with reference to own results which substantiate the theory of local proliferation and blood supply, the bone marrow being however the main source of hepatic macrophages. A few ultrastructural data on Kupffer cells involved in pathological processes are presented.

Acid Phosphatase↗
PubMed1992

[Prenatal moderate effects of alcohol on ultrastructure of cortical capillaries in the offspring].

Sensorimotor cortex of rat 21- and 30-day-old offspring given prenatally moderate alcohol doses revealed signs of hemodynamic, ultrastructural capillary and compensatory-adaptive changes. The 60-day-old offspring displayed the tendency to hemodynamic and ultrastructural reversibility in remaining edema of the pericapillary processes of astrocytes. It is suggested that the deficiency of cerebral circulation is a delayed aftereffect of prenatal brain hypoxia. Under alcohol intoxication before pregnancy the edema was not observed. There was polymorphism of ultrastructure of cortical capillaries and immature vessels in the offspring.

Age Factors↗
PubMed2005

Effects of excess vitamin B6 intake on cerebral cortex neurons in rat: an ultrastructural study.

The aim of this study was to investigate whether excess of vitamin B6 leads to ultrastructural changes in cerebral cortex of forty-eight healthy albino rats which were included in the study. Saline solution was injected to to the control groups (CG-10, n = 12 for 10 days; CG-15, n = 12 for 15 days; CG-20, n=12 for 20 days). The three experimental groups (EG-10, n = 12; EG-15, n = 12; EG-20, n = 12) were treated with 5 mg/kg vitamin B6 daily for 10 days (EG-10), 15 days (EG-15) and 20 days (EG-20). Brain tissues were prepared by glutaraldehyde-osmium tetroxide double fixation for ultrastructural analysis. No significant changes were observed in the control groups. The ultrastructural analysis revealed that the numbers of damaged mitochondria, lipofuscin granules and vacuoles were significantly higher in all the experimental groups than in the control groups (p < 0.05). However, synaptic density was significantly decreased in the experimental groups as compared to the control groups (p < 0.05). The results suggest that the excess of vitamin B6 intake causes damage to the cerebral cortex due to cellular intoxication and decreased synaptic density. Thus, careful attention should be paid to the time and dose of vitamin B6 recommended for patients who are supplemented with this vitamin.

Animals↗
PubMed2005

[Effects of low temperature at 10 degrees C on some antioxidant enzyme activities and ultrastructures of hypocotylar cells in mung bean and garden pea].

Mung bean (Phaseolus radiatus Linn.) and garden pea (Pisum satium Linn.), which were stressed 4 days under a low temperature of 10 degrees C, were used as materials to study the cold tolerance of plant with different resistance. On the 2nd and 3rd day under 10 degrees C stress, both the malondialdehyde (MDA) content and the superoxide dismutase (SOD), catalase (CAT) and peroxidase (POD) activities increased significantly in hypocotylar cells of mung bean, so did SOD activity in garden pea, but other physiological indexes in garden pea were not different from the non-treatment groups (Figs. 1-5). In hypocotylar cells of mung bean, SOD activity always maintain at the highest level in a period of time,and so does POD activity (Figs. 3, 4). Ultrastructural results after stress indicated as follows: (1) Plastids in hypocotylar cells of mung bean accumulated much starch (Plate I-6), whereas the form of plastids in hypocotylar cells of garden pea changed maskedly to become dumb-bell-shaped, round or irregular, with the last one being the most common form (Plate I-8, 12); (2) In both mung bean and garden pea, central vacuole was divided into small vacuoles (Plate I-4, 10), and the number of mitochondria increased and became aggregated (Plate I-3, 11, 12). Judging from the activities of protective enzymes and ultrastructures, 10 degrees C low temperature caused non-lethal, temporary injuries to hypocotyls ultrastructures in mung bean, but no visible injury at all, and even improved its cold tolerance to a certain degree in garden pea.

Catalase↗
PubMed2004

Histopathological and ultrastructural alterations of induced Yersinia enterocolitica infection in mice.

Yersinia enterocolitica is an enteric bacterium and infections by this organism are mostly foodborne. It has been implicated to cause enterocolitis, terminal ilitis. diarrhoea, mesenteric lymphadenitis and arthritis in man. Due to paucity of information regarding histopathological and specially ultrastructural alterations in tissues affected, this study was planned with mice as the experimental model. Nine pathogenic Y.enterocoliticaisolates were used to infect 80 albino mice by oral and intraperitoneal route. Pathological alterations were studied by light and electron microscopy. Histopathological examination of intestines showed severe edema, purulent enteritis, goblet cell hyperplasia infiltration of mononuclear cells, thickening of mucosa and necrosis of the tips of villi. Liver showed congestion, hepatocellular degeneration and necrosis, atrophy of hepatocytes and microabcesses. The lungs revealed congestion, edema, haemorrhage and purulent ronchopneumonia, while kidneys showed mild necrotic changes and bacterial emboli in glomeruli. Ultrastructural changes were indicative of mitochondrial degeneration and their loss in kidneys, membranous degeneration with formation of myelin figures in lungs and disorganization, disruption and bleb formation of microvilli in intestines. Y.enterocolitica caused significant histopathological and ultrastructural alterations in experimentally infected mice. Variation in pathogenicity of different strains of Y.enterocolitica was also observed.

Animals↗
PubMed2005

[Contribution of serial electron microscopy to study of ultrastructure of cerebral cortex].

Stereology was established in 1961, in a range of morphometry, as a science applying mathematical methods for three-dimensional interpretation of two-dimensional data. Serial electron microscopy is one of stereological methods. It enables to analyse series of ultrathin sections and to obtain three-dimensional reconstructions of ultrastructural objects. An extremely complicated architectonics of central nervous tissue, namely the cerebral cortex, does not enable to substitute this difficult method by scanning electron microscopy, which is so suitable for surface analysis of many other non-neural tissue elements. From the times about 45 years ago, when in Sjöstrand's laboratory first ultrastructural three-dimensional reconstructions appeared, this method, now highly computerized, is more and more frequently used and without any doubt it will soon appear as a standard part of any image analyzing software. The author demonstrates on his own three-dimensional reconstructions some results which offer new insights into the ultrastructure of cerebral cortex.

Cerebral Cortex↗
PubMed2005

[The ultrastructure changes of rabbit retina after periodical vacuum suction].

OBJECTIVE: To study the effects of periodical vacuum-suction of different pressures on the ultrastructure of rabbits' retina. METHODS: Rabbits involved in the present study were divided into a control group and four treatment groups, which were treated with vacuum-suction of different pressures through scleral suction ring. The suction pressure was increased at a rate of 100 mm Hg/3 sec (1 mm Hg = 0.133 kPa) and reached (200 +/- 20) mm Hg (group I), (300 +/- 20) mm Hg (group II); (400 +/- 20) mm Hg (group III) and (500 +/- 20) mm Hg (group IV). The suction pressure was maintained for 5 seconds before released to zero. The corresponding intraocular pressure examined by Tonopen was 35 mm Hg, 45 mm Hg, 55 mm Hg and 75 mm Hg in these 4 groups, respectively. This circle was repeated for 10 times with 1 minute interval. The test was repeated every other day. The retina was examined by electron microscope after 2 weeks. RESULTS: There was no obvious difference in the retina ultrastructure between the control group and group I. The retina ultrastructure changed slightly in group II which showed more active metabolism. Some significant changes were found in group III and group IV with cell necrosis in group IV. CONCLUSION: Different elevations of intraocular pressure following periodical vacuum-suction have different effects on the retina of rabbit. Pressure less than 45 mm Hg has almost no effect, but some effects appear at 55 mm Hg pressure, and obviously damages are caused by 75 mm Hg pressure.

Animals↗
PubMed2005

Ultrastructural changes of pancreatic islets microcirculation in nonobese diabetic (NOD) mice.

The objective of this study was to investigate the ultrastructural changes of vascular pancreatic islets using a transmission electron microscopic technique. The major ultrastructural changes of microvessel in NOD mice are indicated by the swelling and vacuolization of the endothelial cell. Swollen cells are the first noticeable lesion of the cell response in reversible degeneration that is caused by the failure of homeostatic control. Loss in endothelial cell homeostasis is primarily a marker of endothelial dysfunction that plays a key role in the pathogenesis of diabetic vascular disease by losing the control of vascular tone. Diabetes also associates with an increased generation of oxygen-derived free radicals that may impair vasodilatation through the inactivation of vasodilators. In conclusion, consistent with a hypothesis that loss of the modulatory role of the endothelium may be a critical and initiating factor in the development of diabetic vascular disease, the ultrastructural changes in this study may indicate the first sign of endothelial dysfunction. This dysfunction correlates to the relationship between diabetes and reversible lesions of vessels in NOD mice, making for a better understanding of the pathophysiology of diabetic vascular disease to set the stage for further investigation to restore endothelial dysfunction in diabetes.

Animals↗
PubMedDate not supplied

The effects of melatonin, N-acetylserotonin, and 6-hydroxymelatonin on the ultrastructure of the pinealocytes of the Syrian hamster (Mesocricetus auratus).

OBJECTIVES: The aim of this study was to examine the effects of melatonin as well as of its precursor (N-acetylserotonin) and metabolite (6-hydroxymelatonin) on the ultrastructure of the pinealocytes of the Syrian hamster. MATERIAL AND METHODS: The pineal glands of 2-month-old male Syrian hamsters were examined. The animals were divided into the following groups of four animals each: group 1 - melatonin treatment; group 2 - N-acetylserotonin treatment; group 3 - 6-hydroxymelatonin treatment (all substances given subcutaneously at doses of 25 microg per animal between 16.00 and 17.00 h daily for seven weeks). Group 4 was given solvent treatment only and served as controls. The animals were killed by decapitation between 09:00 and 10.00 h. Routine electron microscopical techniques were used to obtain quantitative data on pinealocyte ultrastructure. RESULTS: Melatonin administration did not influence the size of the hamster pinealocytes, whereas administration of N-acetylserotonin and 6-hydroxymelatonin caused a significant reduction in cell size in comparison to the melatonin-treated and control groups. There were changes in the relative volumes of the mitochondria, Golgi apparatus and lysosomes in the pinealocytes of the studied groups, while the volumes of granular endoplasmic reticulum and lipid droplets were unchanged. The dense-core vesicles were more numerous in the pinealocytes of the melatonin and 6-hydroxymelatonin-treated groups in comparison to those of animals treated with N-acetylserotonin or the controls. CONCLUSIONS: The changes observed in the ultrastructure of hamster pinealocytes indicate that administration of melatonin as well as of its precursor or metabolite influences the morphology of these cells and also, perhaps, their secretory activity.

Animals↗
PubMedDate not supplied

[Ultrastructural study of liver cells from rooks living in ecologically unfavorable areas].

The ultrastructure of liver cells was studied in rooks (Corvus frugilegus) living in radioactive and chemical contamination areas. The ultrastructure of liver cells from rook as well as jackdaw (Corvus monedula) and hooded crow (Corvus cornix) (Corvidae family) from a conventionally clean area was studied as control. Control hepatocytes proved to contain a great number of mitochondria, many of which were swollen and had clear matrix and disorganized cristae. The cristae nearly lacked glycogen and had abundant lipid droplets, which often tightly contacted mitochondria. The cytoplasm of hepatocytes in birds from both ecologically unfavorable areas had numerous mitochondria with the same ultrastructure. In contrast to control, the hepatocyte cytoplasm: (1) contained a lot of glycogen; (2) there were many lipid droplets, which directly contacted glycogen granules; and (3) had more abundant peroxisomes. In addition to normal erythrocytes, the sinusoids contained erythrocytes with mitochondria, vesicles, and lipid droplets in their cytoplasm. Analysis of many micrographs of lipid droplets contacting glycogen granules, mitochondria, peroxisomes, and cisterns of smooth endoplasmic reticulum allowed us to propose that glycogen is synthesized via gluconeogenesis from glycerol and products of fatty acid oxidation in the liver cell cytoplasm of rooks from ecologically unfavorable areas as distinct from control.

Animals↗
PubMed2006

[Immunological parameters and ultrastructure of blood formed elements in nephrotic syndrome in children].

The aim of the study was the evaluation of significance of immunopathogenic mechanisms in the pathogenesis of minimal change nephrotic syndrome and the study of the ultrastructural changes of peripheral blood formed elements. The observation was carried out on 64 patients with steroid sensitive minimal change nephrotic syndrome. During the manifestation and recurrence of the disease, in the majority of the patients, the results of immunological studies revealed the reduction in both total and absolute count of T-lymphocytes on the background of decreased immunoregulatory index (T(4+)/ T(8+)). In the peripheral blood statistically reliable reduction in the percent value of T(3+) and T(4+) phenotype lymphocytes and elevation of number of T(8+)-lymphocytes were observed. On the background of normal values of B-lymphocytes appeared increase of IgM and decrease of IgG and IgA. In most cases significant elevation in the value of IgE - (244+10,3) and low values of INF-gamma, ultrastructural changes of blood monocytes were apparent. The peculiarities of ultrastructural changes of eosinophils and basophiles especially were pronounced by cytomembrane degranulation in form of decrease in electric density.

B-Lymphocytes↗