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 469 records · Page 26Linked to original sources
PubMed2004

Exercise attenuates diabetes-induced ultrastructural changes in rat cardiac tissue.

INTRODUCTION/PURPOSE: Exercise is an effective nonpharmacological treatment in the prevention of mortality and morbidity due to cardiovascular disease in Type I diabetes. This study sought to explore the effects of endurance exercise on the ultrastructural changes seen in diabetic cardiomyopathy. METHODS: Seven-week-old rats were divided into three groups consisting of sedentary nondiabetic control, sedentary diabetic, and exercised diabetic animals. Diabetes was induced using streptozotocin injection, and the exercised animals were run daily on a treadmill for 9 wk. Changes in heart ultrastructure were analyzed using transmission electron microscopy. RESULTS: Ultrastructural changes in the left ventricle produced by diabetes included changes in myofibrillar arrangements, disrupted mitochondria, and increased cytoplasmic area with an increase in lipid amounts and an increase in individual collagen fiber cross-sectional surface area. Also, an increase in heterochromatin lining the nuclear envelope and an increase in invaginations of the nuclear membrane were observed in cardiomyocytes from diabetic rats when compared with the nuclei from nondiabetic cells. Exercise was found to significantly attenuate the diabetes-induced changes in collagen fibrils, cytoplasmic area, and level of mitochondrial disruption. In contrast, exercise did not appear to significantly influence myofibril volume density, lipid accumulation, or nuclear deformities. CONCLUSION: These findings indicate that exercise restores specific ultrastructural characteristics of diabetic cardiomyopathy returning them toward nondiabetic phenotypes, particularly in the mitochondria and extracellular matrix proteins.

Adaptation, Physiological↗
PubMed1991

Ischemic myocardial mitochondrial function and ultrastructural change--influence of regional myocardial blood flow.

Myocardial blood flow (MBF), tissue ATP content, mitochondrial respiratory function and mitochondrial ultrastructure were examined in 62 adult mongrel dogs weighing 6-14 kg in which acute myocardial ischemia had been produced under anesthesia. The left anterior descending coronary artery was dissected free for ligation before the first diagonal branch. MBF was measured before coronary ligation and 60 min following ligation. Then, samples of myocardium were taken and subjected to tissue ATP content assay, mitochondrial respiratory function measurement respiratory control index (RCI) and rate of oxygen consumption in state III (QO2III); and electron microscopic examination. Mitochondrial morphologic injury was evaluated quantitatively according to Schaper's criteria. MBF was significantly correlated with tissue ATP content, mitochondrial respiratory function and mitochondrial ultrastructural change. When MBF was less than 20 ml/min/100g, tissue ATP content (1.86 +/- 1.21 mumol/g wet weight) and mitochondrial respiratory function (RCI 2.51 +/- 0.59) were significantly lower than in the non-ischemic area (ATP 4.52 +/- 1.11, RCI 3.82 +/- 0.37), and mitochondrial ultrastructural injury had deteriorated significantly at an MBF below 40 ml/min/100 g. In conclusion, our findings show that when MBF is reduced, mitochondrial ultrastructural changes precede the depression in mitochondrial oxidative phosphorylation.

Adenosine Triphosphate↗
PubMed1999

Lectinhistochemistry and ultrastructure of microglial response to monosodium glutamate-mediated neurotoxicity in the arcuate nucleus.

In this study we describe the most relevant morphological features of the microglial reaction that takes place in the arcuate nucleus (AN) after neurotoxic injury induced by a single subcutaneous injection of monosodium glutamate (MSG) in neonatal rats. The time course of the reaction was evaluated by lectinhistochemistry. Microglial/macrophagic cells were labelled with the lectin obtained from Lycopersicon esculentum and with B4 isolectin from Griffonia simplicifolia. The microglial response was also studied by ultrastructural observations. The histochemical study revealed the presence of few reactive microglial cells at 6 h post-injection. These cells were intensely stained and had a globular morphology but contained no neuronal debris inside them when observed under the electron microscope. At 12 h post-injection, the number of microglial cells had increased and, at the same time, intense phagocytic activity was observed ultrastructurally. The microglial reaction peaked at 24 and 36 h post-injection, when the number of microglial/macrophagic cells was maximum, although the ultrastructural observations showed that at 36 h the amount of debris ingested by macrophages was decreased with respect to animals sacrificed at 24 h. Finally, at 4 days after neurotoxic injection the number and morphology of microglial cells were similar to those observed in the control rats. The ultrastructural study also revealed the existence of microglial cell mitosis in the territory of the AN together with a strong increase in the number of supraependymal cells resembling macrophages in the third ventricle during the lesion. Our data demonstrate that activated microglial cells initially extend throughout the damaged territory, but from 24-36 h onwards they are especially patent in the ventrolateral portions of the AN.

Animals↗
PubMed2001

The ultrastructural composition of basement membranes in vivo.

The ultrastructure of basement membranes has a homogeneous appearance. The enormous cell biological importance of basement membranes and their components for cell proliferation, migration and differentiation implies that their composition is more complex than their structure suggests. To elucidate the molecular composition of basement membranes in vivo, we optimised immunogold histochemistry to allow the determination of the molecular arrangement of matrix molecules. Basically, we apply a mild fixation and embed the tissues in the hydrophilic LR-Gold. This preserves the basement membrane with a quality similar to freeze substitution. The application of two antibodies directed toward the C- and N-terminal ends of a molecule and coupled to gold particles of different sizes allows determination of the orientation of a molecule within the basement membrane. We were able to demonstrate that the molecular orientation of the laminin-1 molecule changes in the basement membrane according to cell biological needs. We also showed that ultrastructurally identical basement membranes like the ones of the proximal and distal tubules of the kidney have a differing molecular arrangement. Integrin alpha7 influences the molecular composition of the basement membranes at the myotendinous junction. With the help of double labelling at the ultrastructural level we could show that nidogen-1 is co-localised with laminin-1 and only found in fully developed, mature basement membranes. In general, laminin-1, nidogen-1 and collagen type IV are localised over the entire width of basement membranes, with laminin-1 and nidogen-1 co-localised, in accordance with the current basement membrane models. Incidentally, our investigations warn us, that not every matrix protein found at the light microscopic level as a linear staining pattern underneath an epithelium (basement membrane zone) is a real basement membrane component when investigated at the ultrastructural level. Instead, one and the same molecule, e.g. endostatin, can be a basement membrane component in one organ and a matrix molecule in another.

Animals↗
PubMed2003

Ultrastructural changes in the lungs of neonatal rats intratracheally inoculated with meconium.

Meconium aspiration syndrome has been for many years an important cause of neonatal respiratory distress in newborn babies and sporadically reported in animals. This investigation was designed to study the ultrastructural and morphometric changes in the lungs of neonatal rats following the intratracheal inoculation of meconium. Seven-day-old Fischer-344 rats (n = 24) were randomly allocated in two groups. One group was intratracheally inoculated with saline solution and the second group received homologous meconium. Neonates were euthanatized at 1, 3 and 7 postinoculation days (PID) and lungs were examined by light and electron microscopy. Saline solution did not induce any ultrastructural changes in the lung. In contrast, meconium induced deciliation, recruitment of neutrophils and pulmonary alveolar macrophages to the bronchoalveolar space, intravascular sequestration of neutrophils and aggregation of platelets at PID 1 and 3. Other ultrastructural changes at PID 1 and 3 included interstitial edema and escape of red cells and fibrin into the alveolar space and interstitium. Interstitial edema and sequestration of neutrophils were responsible for the significant increase in thickness of alveolar septa. At PID 7 there was hyperplasia and enlargement of type II pneumocytes as well as interstitial proliferation of mesenchymal cells with intra-alveolar fibrosis. It was concluded that intratracheal inoculation of meconium in neonatal rats induces acute ultrastructural changes followed by a reparative response.

Animals↗
PubMed1977

Ultrastructural integrity of mouse testicular cells separated by velocity sedimentation.

Mouse testicular cells were examined ultrastructurally to determine whether the cells are damaged during the preparation of single-cell suspensions or during cell separation. The testicular cells were dissociated from seminiferous tubules by trypsinization and were fixed immediatley; fixed after being held in suspension for 4 h at 4 degrees C; or fixed after being separated into enriched fractions by sedimentation velocity either at unit gravity or by centrifugal elutriation. In general, the ultrastructural integrity of the cells, compared with that of corresponding testicular cells fixed in situ, was maintained during the dissociation and separation procedures. Ultrastructural abnormalities were most frequently produced in Sertoli cells and were occasionally observed in the acrosomes and nuclei of round spermatids. The cytoplasmic matrix of the midpiece of mature elongated spermatids or spermatozoa and the acrosomes of these cells were often disrupted. It is suggested that the dissociation procedures were responsible for most of the observed alterations of ultrastructural integrity.

Acrosome↗
PubMed1998

[Diagnosis of metabolic diseases of the nervous system in children through ultrastructural analysis of non cerebral tissue].

Although biochemical and molecular genetic analysis are the most precise methods for the diagnosis of metabolic diseases, morphological studies remain a very important diagnostic method mainly in countries like Brazil, where clinical laboratories are unable to perform most of the exams required for the diagnosis of these diseases. Moreover, pathologic evaluation is the single diagnostic method for some disorders whose metabolic defect is unknown such as neuronal ceroid-lipofuscinosis, infantile neuroaxonal dystrophy or Lafora disease. We present our experience with ultrastructural analysis in 582 exams of ocular conjunctiva (n = 320), skin (n = 92) or peripheral nerve (n = 170) performed between 1975 and 1996, in 486 children. In 112 cases there were definite ultrastructural changes. In 59 cases, the sole ultrastructural exam allowed the diagnosis. In 29, the changes were less specific, and the final diagnosis was performed by a combination of clinical and pathological analysis. In the remaining 24 cases, a generic diagnosis of mucopolysaccharidosis was done in 8 cases, oligosaccharidosis in 4 cases and GM2 gangliosidosis in 12 cases. Whenever a biochemical test was performed in overseas laboratories, the initial diagnosis was confirmed. These results stress the importance of ultrastructural analysis in non-cerebral tissues for the diagnosis of many metabolic disorders mainly when biochemical tests cannot be performed.

Central Nervous System↗
PubMed2001

Morphometric and ultrastructural analysis of different pituitary cell populations in undernourished monkeys.

Undernutrition elicited by a low-protein diet determines a marked reduction of hypophyseal activity and affects the function of the respective target organs. The objective of the present investigation was to study the ultrastructural and quantitative immunohistochemical changes of the different pituitary cell populations in undernourished monkeys that had been previously shown to have significant changes in craniofacial growth. Twenty Saimiri sciureus boliviensis monkeys of both sexes were used. The animals were born in captivity and were separated into two groups at one year of age, i.e., control and undernourished animals. The monkeys were fed ad libitum a 20% (control group) and a 10% (experimental group) protein diet for two years. Pituitaries were processed for light and electron microscopy. The former was immunolabeled with anti-GH, -PRL, -LH, -FSH, -ACTH, and -TSH sera. Volume density and cell density were measured using an image analyzer. Quantitative immunohistochemistry revealed a decrease in these parameters with regard to somatotrophs, lactotrophs, gonadotrophs and thyrotrophs from undernourished animals compared to control ones. In these populations, the ultrastructural study showed changes suggesting compensatory hyperfunction. On the contrary, no significant changes were found in the morphometric parameters or the ultrastructure of the corticotroph population. We conclude that in undernourished monkeys the somatotroph, lactotroph, gonadotroph, and thyrotroph cell populations showed quantitative immunohistochemical changes that can be correlated with ultrastructural findings.

Animals↗
PubMed2001

Ultrastructure and chaetotaxy of sensory receptors in the cercariae of a species of Crepidostomum Braun, 1900 and Bunodera Railliet, 1896 (Digenea: Allocreadiidae).

Previous investigations of cercarial sensory systems have focused on chaetotaxy and ultrastructure of sensory receptors and have revealed chaetotaxic patterns within families, genera, and species as well as different types of sensory receptors. However, chaetotaxic and ultrastructural observations have rarely been combined. We investigated the ultrastructure of cercarial sensory receptors in conjunction with the chaetotaxy and neuromorphology in 2 allocreadiid species belonging to the genera Crepidostomum and Bunodera. Cercariae were treated with acetylthiocholine iodide and silver nitrate, and for scanning electron microscopy (SEM) and transmission electron microscopy (TEM). Similar cholinergic nerve networks were revealed. Chaetotaxy was consistent with that of other allocreadiids. Seven and 6 types of receptors were distinguished with SEM in Crepidostomum sp. and Bunodera sp., respectively. Types differed in number of cilia (1 or 2), cilium length (short, moderately long, or long), presence or absence of a tegumentary collar and a domelike base, and tegumentary collar length (low, moderately low, or high), TEM of some types revealed unsheathed cilia, basal body, and thickened nerve collars. Some receptor types were site specific. Thus, long uniciliated receptors were concentrated on the dorsal surface. Other types, such as short uniciliated receptors, were widespread throughout most regions. Ultrastructure and site-specificity observations suggest that most receptors are mechanoreceptors.

Acetylthiocholine↗
PubMed1982

Ultrastructural studies of spermatozoa and the epithelial lining of the epididymis and vas deferens in rats treated with gossypol.

This study was undertaken to determine the effects at early time intervals of gossypol on sperm motility and on the ultrastructure of rat epididymal and vasal sperm and epididymal and vasal epithelium. Rats were treated by gavage with 20 or 30 mg/kg/day of gossypol for 7 weeks; control animals were unfed or received the vehicle alone. The results confirm and extend earlier observations demonstrating that epididymal sperm of gossypol-treated rats exhibit distinct ultrastructural changes under the experimental conditions employed. The severity and frequency of the degenerative changes appear to increase with dose and duration of treatment. Striking ultrastructural defects can be seen as early as 3 weeks after 20 mg/kg/day of gossypol. By the fifth week of either 20 or 30 mg/kg/day of gossypol, significant damage to virtually all sperm flagella is observed throughout the epididymal duct of all treated rats. The initial and predominant defect is degeneration of the midpiece mitochondria but additional flagellar defects are described in detail. Not surprisingly, caudal spermatozoa are totally immotile by the fifth week. The ultrastructure of the epididymal and vasal epithelium is not affected by gossypol.

Animals↗
PubMed1983

The ultrastructure of rat type II pneumocytes: effects of age, sex, and strain.

The morphology of type II pneumocytes was investigated in Fischer 344 and Sprague-Dawley rats to determine whether differences in age, sex, and/or genetic strain influence type II cell ultrastructure. In Fischer 344 rats the type II pneumocytes increased in size with age due to an increase in the cytoplasmic component of the cell. Although mitochondrial volume density increased with age no significant changes in lamellar body volume density or lamellar body size were detected. No ultrastructural differences were observed between the type II cells in 6-week-old male and female Fischer 344 rats. However, substantial ultrastructural differences were found to exist among type II cells from the Fischer and Sprague-Dawley strains. Lamellar body volume density was 60% greater, P less than 0.001, in the Fischer rats due to the larger size of individual lamellar bodies. While mitochondrial volume density was also 22% greater in the Fischer rats, P less than 0.01, type II cell size was similar in the two strains. These results indicate that the ultrastructure of type II cells can differ within a genetically inbred strain as a function of age as well as between genetically different strains of the same species.

Age Factors↗
PubMedDate not supplied

Ultrastructure of liver cell and bile duct carcinomas.

The primary concerns of the surgical pathologist examining a biopsy specimen are whether a particular neoplasm is originating within the liver or is metastatic and, if a primary, whether differentiation is toward liver cells or bile ducts. The present study was undertaken in the hopes of providing a broader concept of the ultrastructural spectrum of liver cell carcinoma (LCC) and a more precise understanding of the changes occurring in these neoplasms with dedifferentiation. The 20 liver cell carcinomas, 13 bile duct carcinomas (BDC), and 3 hepatoblastomas were studied ultrastructurally and the findings correlated with light microscopic sections stained by hematoxylin-eosin and the periodic acid-Schiff procedure with and without prior diastase digestion. Immunocytochemical staining for alpha 1-antitrypsin was carried out on selected tumors. Ultrastructural study can be useful in the distinction of LCC from BDC in the minority of cases in which this is difficult by light microscopy. While true mixed tumors appear to be uncommon, duct formation can be simulated by LCC cells. The extent to which electron microscopy will enable the pathologist to separate metastatic neoplasms in the liver from primary liver cell tumors depends on the relative ultrastructural features. Assessment of the value of electron microscopy as an aid to light microscopy in the histologic grading of LCC and BDC will require further study.

Adolescent↗
PubMedDate not supplied

Ultrastructural postembedding immunogold labeling: applications to diagnostic pathology.

Ultrastructural postembedding immunogold labeling combines the advantages of routine transmission electron microscopy and detection of antigenic epitopes. As a result, morphologic findings can be accurately interpreted. Localization of morphologic correlates for the various antigenic determinants allows a good definition of the applications and limits of immunocytochemistry in diagnostic surgical pathology. In some cases, immunofluorescence and immunocytochemistry results at light- microscopic levels can be either validated or determined to be nonspecific. Application of ultrastructural immunolabeling to surgical pathology is no longer a distant possibility but rather a reality. The technique provides reliable and reproducible results. Image analysis and microanalytical techniques applied to ultrastructural immunolabeling serve objectively to analyze and clearly to portray results. This paper describes experience with ultrastructural immunolabeling of various renal diseases and neoplasms by means of an easy-to-use methodology that can be applied to the evaluation of specimens in a diagnostic surgical pathology laboratory.

Humans↗
PubMedDate not supplied

An atypical ultrastructural pattern in Fabry's disease: a study on its nature and incidence in 7 cases.

This is a report on a stored lipid atypical ultrastructural pattern in skin samples of Fabry's disease expressed exclusively in the endothelium. The pattern consisted of intersecting short crescentic tightly packed membranes with a periodicity identical to that in classical ultrastructural variants. At low magnification the lysosomal aggregates of the material resembled "sunbursts" or aggregates of densely packed squirming villus-like structures. According to results of ultrastructural, lipid, and lectin histochemical analyses including analysis of the patients' blood groups, it could be concluded that it is just a variant physical state of the otherwise typical Fabry lipid. Its origin could be attributed to impeded formation (or maintenance) of larger lipid lamellae. It was found in great amounts in skin capillaries in 2 cases, and rarely in 5 additional cases. Knowledge of this atypical ultrastructural pattern is of practical significance because it could, if prevalent, cause diagnostic problems.

Adolescent↗
PubMedDate not supplied

A light microscopical, immunohistochemical, and ultrastructural comparison of hemangiomata and lymphangiomata.

In this study we have compared the light microscopical, immunohistochemical, and ultrastructural features of five hemangiomata of the dermis with five lymphangiomata of the dermis and subcutaneous tissue. We have attempted to define differentiating features with regard to the ultrastructural appearances and the immunohistochemical staining for the endothelial markers factor VIII-related antigen (FVIII:RAg) and Ulex europaeus agglutinin I (UEA-I). In addition, immunolocalization of FVIII:RAg at the ultrastructural level was performed to compare its distribution within endothelial cells of neoplastic blood vessels and lymphatic vessels. The results show that immunohistochemical staining for FVIII:RAg and UEA-I does not differentiate between blood and lymphatic vessels. However, the presence of a fragmented basal lamina and anchoring filaments does distinguish lymphatic vessels from blood vessels ultrastructurally.

Adolescent↗
PubMedDate not supplied

Colloid cyst of the third ventricle: a comparative ultrastructural study of neuraxis cysts and choroid plexus epithelium.

Thirteen colloid cysts (CC), four Rathke cleft cysts (RCC), three follicular cysts of normal pituitary gland (FCP), four enterogenous cysts (EC), three normal choroid plexi (CP), three choroid plexus papillomas (CPP), and several samples of normal bronchial mucosa and ependyma were studied by electron microscopy. The ultrastructure of most of the CC was indistinguishable from that of RCC, FCP, EC, and normal bronchial mucosa in demonstrating nonciliated and ciliated epithelial cells, goblet cells, basal cells, and intermediate forms, some showing evidence of early squamous differentiation. Two CC displayed mostly squamous differentiation, and one contained basally situated cells resembling myoepithelial cells. Although the RCC and FCP displayed features similar to those of CC, they also contained cells with electron-dense granules indicating pituitary hormone production and scattered cells showing oncocytic change. EC were lined by either squamous cells or mucin-producing columnar cells. Every CC, RCC, FCP, and EC contained cells covered by glycocalyx. In contrast to aforementioned lesions, ependymal lining, CP, and CPP were composed of a single cell type, one with numerous villi, few cilia, and no signs of keratinization, mucin production, or glycocalyx coating. It is concluded that the ultrastructural properties of CC are the same as those of cysts of endodermal or ectodermal origin and of respiratory mucosa. No ultrastructural similarities were observed between CC and normal or neoplastic neuroepithelium. These ultrastructural findings support the concept of an enterogenous origin of colloid cysts and highlight their similarity to RCC.

Cerebral Ventricles↗
PubMedDate not supplied

Comparative ultrastructure of needle aspiration biopsy and surgical resection specimens of lung tumors.

Ultrastructural examination affords conclusive evidence for classification of lung tumors. Tissue properly fixed for electron microscopy is not available in many cases, however. Ultrastructural diagnosis of resected specimens obviously follows, rather than directs, the surgical treatment. Fine-needle aspiration (FNA) of lung masses is recommended as a means to obtain lung tumor tissue for electron microscopy. Nevertheless, no comparison has been made between ultrastructural information gained from aspiration specimens and resected specimens. Electron microscopy was performed on transthoracic FNA specimens of 10 lung tumors for which surgical resection was subsequently performed. Glutaraldehyde-fixed specimens from FNA and surgical resection were prepared for electron microscopy according to routine procedures. Fixation of the FNA specimens was equivalent or superior to that of the resected specimens in 9 of the cases. Three of the FNA specimens contained necrotic as well as viable tissue. Features essential for diagnosis such as desmosomes, junctions, neurosecretory granules, intermediate filaments, glycogen, lipid, mucin, and microvilli were identifiable in both FNA and resected specimens. FNA specimens therefore yield a representative sample of the ultrastructural features of lung tumors when adequate cellular material is obtained. Use of a coaxial needle sampling technique with immediate microscopic assessment reduces the likelihood of retrieving only blood or necrotic tissue in the electron microscopy specimens.

Adult↗
PubMedDate not supplied

Ultrastructural immunolabeling: a general overview of techniques and applications.

Ultrastructural immunolabeling techniques combine the advantages of routine electron microscopy and detection of antigenic epitopes, the latter of which is customarily done by immunocytochemistry at the light microscopic level. In surgical pathology, immunocytochemistry has become routine to approach the differential diagnosis of difficult cases. Immunoelectron microscopy has been used primarily for research purposes or for addressing specific questions in diagnostic pathology. Ultrastructural immunolabeling is extremely useful in those instances in which the ultrastructural and immunocytochemical findings are not pathognomonic and are subject to interpretation. Preembedding and postembedding labeling techniques have been described in the literature. Preembedding techniques are not as applicable to diagnostic work, however. Their use remains rather limited to applications in which the antigen to be labeled cannot maintain its viability when exposed to fixatives. Even in such cases a new methodology--the LifeCell process--has emerged; this technique cryofixes tissues, thereby maintaining antigenic integrity. After cryofixation, a postembedding labeling technique can be utilized. Immunogold and peroxidase methods are used for labeling. Immunogold methods elegantly mark reaction sites with preservation of underlying morphology. Postembedding immunogold methods are used by most individuals working in the field. Ultrastructural labeling techniques are rapidly moving from classification as exclusively research tools to the diagnostic arena.

Cryopreservation↗