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At least 487 records · Page 27Linked to original sources
PubMed1984

Karyometric investigations on urinary bladder carcinoma, correlated to histopathological grading.

The aim of this study is to provide karyometric data which may be of value in the grading of urinary bladder tumours. For this purpose 27 biopsies were studied: four from normal bladder mucosae, eleven from grade I tumours, six from grade II tumours and another six from grade III tumours, according to a I-IV scale. After standardized fixation and plastic embedding, semithin sections were used for light microscopic stereology. Mean profile areas and mean volume densities of the nuclei tended to be higher in the more malignant cases. The nuclear volume densities were significantly higher in grade II than in grade I. The most important finding relates to the large nuclear profiles (greater than 90 microns 2), which were found almost exclusively in grade III tumours. Simple measurements of nuclear size can thus provide objective data to aid in the diagnostic procedure.

Aged↗
PubMed1987

Histopathology of bone marrow in human immunodeficiency virus infection.

The clinical and haematological findings in 18 patients with human immunodeficiency virus (HIV) infection were correlated with the histological features of plastic embedded bone marrow biopsies. Fifteen patients presented with peripheral cytopaenia of one or several cell lines. Twelve (66%) of the 18 patients exhibited bone marrow findings including normo- to hypercellularity, myelodysplasia, lymphocytosis with or without plasmacytosis and fibrosis of the reticulin type. Seventeen patients had myelodysplastic features, 5 of the 3 haematopoietic lines, 10 of 2 lines and 2 of 1 line. Dysmegakaryocytopoiesis and dyserythropoiesis, seen in 88% and 83% of the 18 patients respectively, were the most common myelodysplastic features. Bone marrow gelatinous transformation (serous atrophy) was a conspicuous finding in 7 (38%) of the 18 patients. The constellation of histological features here described, although not pathognomonic, is highly suggestive of HIV infection. The pathogenesis of the haematological abnormalities in HIV infection is discussed.

Acquired Immunodeficiency Syndrome↗
PubMed1986

Dimensional changes of proximal tubules and cortical capillaries in chronic obstructive renal disease. A light microscopic morphometric analysis.

The study was carried out to determine the proximal tubular length, surface area and length of peritubular capillaries and the nephron numbers in kidneys with chronic nephropathy and varying increase in the cortical interstitial volume. Kidneys of pigs with varying chronic obstructive nephropathy were used for the experiments. Two subgroups of ureter-obstructed kidneys were defined arbitrarily according to the volume of cortical interstitium. One subgroup (I) comprised kidneys with a volume fraction of cortical interstitium less than 30% (mean 17.2%; mean of controls 9.7%). The other subgroup (II) consisted of kidneys with severe chronic nephropathy and with a volume fraction of interstitium more than 30% (mean 44.5%). Proximal tubular length and length and surface area of peritubular capillaries were assessed by conventional morphometric techniques on 1 micron thick sections of plastic embedded material. Nephron numbers were determined by a stereological method for counting glomeruli. The results demonstrated that proximal tubular length and capillary dimensions were significantly reduced in subgroup II, whereas no significant changes were observed in subgroup I. The mean number of glomeruli was not significantly different from control values in any of the subgroups. The results are in line with observations from previous quantitative analyses of proximal tubular cross-sections indicating that proximal tubular dimensions become reduced mainly at advanced stages of chronic nephropathy. The results also indicate that shortening of individual tubules rather than loss of entire nephrons is responsible for the observed reduction in total length of proximal tubules. Finally, the present observations suggest that reduced dimensions of the cortical capillary network may have pathogenetic significance for ongoing proximal tubular atrophy in chronic renal disease.

Animals↗
PubMed1997

Frequency of pseudo-Gaucher cells in diagnostic bone marrow biopsies from patients with Ph-positive chronic myeloid leukaemia.

Pseudo-Gaucher cells (PGC) are a characteristic finding in Ph-positive CML, and prolongation of survival was observed when PGC were detected within the bone marrow. However, the conspicuous variation in the reported frequencies indicates the necessity for analysis of their natural occurrence in the bone marrow from untreated CML patients. A total of 833 diagnostic bone marrow biopsies from patients with Ph-positive CML were examined for PGC by 7 observers. Proof of PGC was based on systematic examination of Giemsa-stained slides with and without polarization at high magnification. Birefringence within the cytoplasm turned out to be highly specific for PGC. The risk of overlooking PGC was at least 80% when the number of these storing histiocytes was 70 per slide or less, and at least 50% when the total amount per slide was < or = 250. This high risk of failure explained the disagreement among the authors. An intensive investigation by at least two observers is mandatory if results are to be evaluated in research. Under the conditions used in this study, the natural frequency of PGC within the bone marrow from untreated patients with a Ph-positive CML is much higher than assumed to date, amounting to about 70%. On the basis of these findings, the prognostic importance of PGC in CML must be evaluated critically.

Adult↗
PubMed1992

Prostaglandin E2 localization in the rat ileum.

The application of anti-prostaglandin E2 immunoglobulin to plastic-embedded thin sections of the rat ileum has permitted the localization of prostaglandin E2 in this tissue. In agreement with the published data (Chock & Schmauder-Chock (1988), Schmauder-Chock & Chock (1989)), the results also suggest the presence of an arachidonic acid cascade in the granules of various secretory cells of the gut. Since antibody labelling was found within the secretory granules of connective tissue mast cells, goblet cells, and Paneth cells, the presence of the arachidonic acid cascade in these granules is implied. The appearance of prostaglandin E2 over the non-cellular internal elastic lamina of arterioles suggests that it may have been secreted along with the elastin. The even distribution of prostaglandin throughout the cytoplasm of the erythrocyte is consistent with the concept that this cell scavenges the eicosanoid from the circulation. These data further link the secretory granule to the production of eicosanoids and therefore illustrate the potential sources of prostaglandins in the rat ileum.

Animals↗
PubMed1995

Microwave irradiation improvements in the silver staining of the nucleolar organizer (Ag-NOR) technique.

The well-known technique of silver staining of the nucleolar organizer (Ag-NOR) is improved in contrast, selectivity and speed when performed with microwave irradiation. The Ag-NOR technique is a very useful tool for studies on the functional morphology and molecular architecture of the nucleolus, and is reputed to be one of the best techniques for diagnosis and prognosis of cancer lesions. To test the generality of the enhancing effects, our study has involved the use of both mammalian and plant cells. Two steps in the process are improved quantitatively by microwave irradiation: fixation and staining itself. Fixation with the ethanol-based reagent, Kryofix, for 3 min in the microwave oven, resulted in good structural preservation at the optical level, and enhanced the contrast and selectivity of silver staining. On the contrary, we found that neither glutaraldehyde fixation, nor a treatment of sections with Carnoy's solution, improved Ag-NOR staining. After an analysis of the effects of the different substances involved in sample preparation, we conclude that ethanol is an essential factor for fixation for nucleolar staining, particularly if aldehydes are eliminated from fixative solutions. The process of staining was performed with a drop of staining solution on a semithin section of plastic-embedded tissue in the microwave oven for 1 min. Staining under these conditions always improved the visualization of nucleoli, regardless of the fixation procedure. Therefore, microwave irradiation at both steps is recommended for giving the best results. Microwave irradiation probably enhances fixation by controlled heat, whereas the increase in reactivity of the staining solution is a direct effect by the microwaves on the silver ions themselves. We used this method to study nucleolar materials during mitosis in proliferating plant cells. Current applications of Ag-NOR staining can be improved with this technical modification.

Animals↗
PubMed1986

Improvement in the staining and in the visualization of the argyrophilic proteins of the nucleolar organizer region at the optical level.

The argyrophilic proteins of the nucleolar organizer region (Ag-NOR proteins) were specifically localized at the optical level with a modified one-step silver technique performed at 20 degrees C. This method was applied to various materials including cells in smears, chromosomes, semi-thin sections of plastic-embedded cells and sections of paraffin-embedded human pathological tissues. In order to improve the visualization of the silver deposits we tested various modes of imaging, including bright-field, Nomarski contrast, reflected light and combined Nomarski contrast with reflected light. The use of Nomarski contrast is useful to define precisely the phases of mitosis. The use of reflected light, which is based on the ability of silver to reflect incident light specifically, gives images with an improved resolution compared to bright-field.

Cell Line↗
PubMed1991

Local effects of impaired mechanical properties of collagen on bone formation and resorption.

To study the relationship between the mechanical properties of collagen and the bone turnover, 2-week-old Balb/C mice were fed on a diet containing 0.25% Beta aminopropionitrile (B-APN), a potent inhibitor of collagen crosslink formation, for 3 weeks. Mandibular incisor socket was selected for the analysis of bone formation and resorption parameters. Plastic embedded sections stained with toluidine blue and cut at 4 microns were used to analyze the average area of bone lamellae, bone-forming surface, and the number of osteoblasts/mm of forming surface. Similar sections were used to localize acid phosphatase on resorbing surfaces and within the osteoclasts, while bone alkaline phosphatase was determined by a colorimetric method. Morphometric analyses showed that the area of newly formed bone lamellae, total forming surface, number of osteoblasts and the Alk. Pase activity were significantly lower in B-APN-fed mice as compared to the controls. There was a concomitant smaller, but significant, reduction in total resorption surface, active resorption surface and the number of osteoclasts. These results suggest that the regulation of bone formation and resorption at this site, which is independent of systemic regulation, is influenced by the mechanical properties of the collagenous matrix, which in turn may have a significant effect on the existing pool of bone-forming cells, but may not influence the recruitment of new cells.

Acid Phosphatase↗
PubMed1996

Differential immunocytochemical localization of calretinin in the pineal gland of three mammalian species.

Calcium plays an important role for signal transduction in the mammalian pineal organ. The regulation of the intracellular concentration of free calcium probably involves calcium-binding proteins of the calmodulin superfamily. In the present study, we have investigated the expression of calretinin, one member of this superfamily, in the pineal organ of hamsters, gerbils and guinea-pigs by means of immunochemical and immunocytochemical analyses with a calretinin-specific antiserum. In immunoblots this antibody recognized a single protein band of approximately 29 kDa in the brain and pineal organ of all three mammalian species. Immunocytochemical investigations of serial semithin sections of plastic-embedded pineals revealed the constant occurrence of variable numbers of calretinin-positive cells throughout all glands. In order to identify the immunopositive cells precisely, adjacent sections were exposed to antibodies against various marker proteins of pineal cell types, i.e., synaptophysin, neuron-specific enolase, protein gene product 9.5, S-antigen, vimentin and S-100. By this approach, calretinin could be localized to vimentin-positive cells in the gerbil which are generally considered as interstitial glial cells. Likewise, calretinin-positive cells in the guinea-pig probably correspond to interstitial cells, taking into account their morphology and the lack of calretinin immunoreactivity in pinealocytes. The unusual expression of calretinin in astrocyte-like cells further supports the notion that pineal glial cells are endowed with peculiar properties. In contrast to gerbil and guinea-pig, a subpopulation of pinealocytes displayed calretinin immunoreactivity in the hamster. This finding adds to the hypothesis that in pinealocytes of some species calretinin plays a role in calcium-mediated signal transduction which eventually is linked to melatonin synthesis. Our results demonstrate that calretinin is a regular constituent of pineal glands in three mammalian species, but that its cellular localisation shows interspecific variation. This variation suggests that the protein is involved in diverse calcium-mediated functions in the mammalian pineal gland.

Animals↗
PubMed1996

Ultrastructural localization of a synaptic ribbon protein recognized by antibody B16.

This study examines the immunolabelled structures in the mouse retina following incubation with a monoclonal antibody (B16) that recognizes a highly conserved antigen found in retinas from lizards, frogs, fish, birds, mice, rats, rabbits, cats, and monkeys. This paper focuses on observations in the murine retina. The B16 labelling pattern in the retina was compared with that of two synaptic vesicle antigens: SV2 and anti-synaptophysin in the outer plexiform layer were more diffuse and apparently filled the entire presynaptic terminal whereas B16 labelling was more restricted and labelled a discrete structure resembling a semi-ellipse or an arc with the ends pointing to the inner nuclear layer and the middle curve facing the outer nuclear layer (1-2 microns long by < 0.05 micron in width). The structure labelled in the inner plexiform layer resembles a short bar (0.8 micron long by < 0.05 micron in width) that is confined to the inner half the inner plexiform layer. Cryo-ultra microtomy was used to examine the ultrastructural distribution of the labelling, because the B16 epitope is sensitive to fixation and plastic embedding. The tissue was incubated with the B16 antibody and visualized with goat-anti-mouse 10 nm gold particles. In all cases label was found to be confined to the ribbon structure in the photoreceptor terminal. This is consistent with previous evidence linking B16 to an epitope associated with the synaptic ribbon. The labelling is confined to the ribbon structure and does not appear to be associated with synaptic vesicles.

Animals↗
PubMed1996

A new version of the Ag-NOR technique. A combination with DAPI staining.

The Ag-NOR staining technique is widely used for visualizing nucleolar organizer regions (NORs) in various plant and animal tissues. We describe a simple and time-saving combination of Ag-NOR staining with DNA detection by fluorescence microscopy. This modification was tested on cultured cells and semi-thin sections of plastic-embedded tissues. Of the different fixatives and embedding media used in our studies, the best results (i.e., high selectivity of staining, and lack of or very low background precipitation) were obtained with fixation in methanol-acetone at-20 degrees C for cultured cells, and fixation in 4% formaldehyde followed by embedding in Histocryl resin for tissue sections. The optimal time of Ag-NOR staining was determined experimentally for all materials tested. The specificity of the staining was checked at the electron microscopical level. Especially good results were obtained by mixing epifluorescence with standard bright-field illumination. In such a combination, Ag-NOR-positive nucleoli, or their fibrillar centres and dense fibrillar components, were clearly visible against a bright background of nuclear DNA.

Animals↗
PubMed1997

Plastination of the larynx for whole-organ sectioning.

Whole-organ sectioning is an important technique for the assessment of laryngeal pathology. Since currently established methods require prior decalcification which causes morphological changes, the critical border area between cartilage and surrounding soft tissue cannot be investigated in the same specimen and morphometric studies are not possible. Plastination is a laboratory technique that has previously demonstrated its capacity to overcome these shortcomings. In so doing water and lipids are replaced by curable polymer within the laryngeal cells making decalcification unnecessary. In the present study, more than 50 human larynges were processed using block plastination (BP) and sheet plastination (SP). For BP the complete organ was plastinated as a whole and then cut into thin serial sections. For SP the fresh organ was sliced first and plastinated in a second step. Findings demonstrated that SP allowed for the production of whole-organ sections within a period of 1 week only. Section thicknesses were as thin as 15 mm using a diamond wire saw and an ultramilling device. Sectioning was possible in both coronary and horizontal planes. Following BP, specimens were cut in an industrial cutting machine to thicknesses of about 0.6 mm. Shrinkage of tissue was less than 10% for both methods. In all, SP was technically superior to routine paraffin histology, although cutting equipment is very expensive and delicate in handling. At present the technique of BP is the method of choice for macromorphometrical investigations on serial sections of the human larynx.

Acetone↗
PubMed1987

Microglia in the hypendyma of the rat subcommissural organ following brain lesion with serotonin neurotoxin.

The population of microglial cells in the subependymal layer of the subcommissural organ is sparse in normal adult rats. The number of microglial cells was substantially increased in this area following intraventricular injection of the serotonin neurotoxin 5,6-dihydroxytryptamine (5,6-DHT). In sections of plastic embedded material, 1 micron thick, the majority of phagocytic cells scattered in the subependymal layer had an appearance similar to that described in classical studies of microglial cells. At the electron microscopic level microglial cells exhibited the characteristic elongate nucleus with peripheral chromatin condensation. The perikaryon was scanty, containing strands of rough endoplasmic reticulum. The abundant organelles in the processes included Golgi complexes, mitochondria, rough and smooth endoplasmic reticulum as well as dense and multivesicular bodies. In addition, the processes contained phagocytosed axon terminals originating from the dense serotoninergic input to the subcommissural organ, which had degenerated on accumulating the serotonin neurotoxin. A fraction of the phagocytosed material was contained in subependymal subcommissural organ cells, astrocytes and oligodendrocytes. At the light microscopic level the phagocytosed terminals were visualized histochemically with Schmorl's reaction, which resulted in Prussian Blue precipitates. This allowed screening of microglial cells in complete series of sections through the well-defined subependymal layer of the subcommissural organ.

5,6-Dihydroxytryptamine↗
PubMed1989

Histomorphometry of fresh frozen iliac crest bone biopsies.

Although methods are well established for the rapid histological preparation of fresh frozen soft tissues, they remain inadequate for the preservation of hard tissues. A recent technique for sectioning fresh frozen bone, in which sections can be prepared within an hour, has been applied to undecalcified human iliac crest bone biopsies. Quantitative analysis has shown that the static remodeling variables deduced from frozen sections closely resemble those derived from plastic-embedded sections prepared for routine use by established laboratory procedures. It is concluded that the rapid method is reliable for immediate diagnostic and histomorphometric purposes.

Biopsy↗
PubMed1988

Resolution as a function of accelerating voltage in electron microscopy of semithick biological specimens.

In the past, biological sections ranging in thickness from 0.10- to 0.50-micron have usually been examined with high-voltage (greater than 500 kV) electron microscopes (HVEM). Now investigators are increasingly using intermediate voltage (200-500 kV) electron microscopes (IVEM), which are more readily available and demand less maintenance. In a study of "typical" plastic-embedded, stained sections of mouse liver ranging from 0.10 to 1.0 micron thick, we determined the resolution obtainable at 100, 200, and 1000 kV. At all three accelerating voltages the resolution (2.7 nm) for 0.10-micron sections was limited only by the sections stain granularity. For 0.25-micron thickness the resolutions were 5.8, 3.1, and 3.1 nm at 100, 200, and 1000 kV, respectively. The maximum usable thickness at 200 kV with resolution sufficient to resolve membranes clearly was between 0.75 and 1.0 micron, depending on the magnification. Resolution at 100 kV was adequate for screening sections up to 1.0-micron thick for preparation defects prior to examination with an IVEM or HVEM.

Animals↗
PubMed1983

Abnormal iodoprotein distribution and resistance to proteolysis in Gunn rat black thyroid. An ultrastructural and biochemical study.

Gunn rats have a marked deficiency in hepatic UDP-glucuronosyl transferase activity which results in hyperthyroxinemia and hyperbilirubinemia. Their thyroids show a brownish-black discoloration associated ultrastructurally with intracellular dense granules and intraluminal dense masses. In order to determine whether colloid composition and colloid proteolysis are altered in the thyroid of the Gunn rat compared with the Wistar rat, we studied the in situ resistance of thyroid proteins to in vitro proteolysis, the pattern of in vivo (125I) labeled thyroid iodoproteins and the proteolysis of isolated iodoprotein fractions in both strains of rats. For the cytochemical study, thin sections of aldehyde-fixed and plastic-embedded thyroid tissue were treated with 0.3 or 1% pronase in aqueous solution. With the low concentration of pronase, the secretory granules in C-cells and the apical vesicles in follicular cells were extensively digested in both strains of rats, whereas the colloid in the follicular lumen and the colloid droplets were only partially digested. With the high concentration of pronase, the colloid in the lumen and the colloid droplets were more markedly digested in both strains. In the presence of both concentrations of pronase, the dense granules and intraluminal dense masses were unchanged in the Gunn rats. The (125I) iodoprotein pattern was investigated 24 h after a single injection of (125I) iodide and by labeling at the isotopic equilibrium. It was found that the (125I) thyroglobulin fraction was reduced, whereas the (125I) 3-8 S fraction was increased in Gunn rats compared to Wistar rats. Pronase hydrolysis of the soluble (125I) iodine fraction showed similar pronase-resistant fractions in both strains with the single labeling procedure. At the isotopic equilibrium, the pronase resistant fraction was significantly increased in Gunn rats (Gunn 24.0 +/- 5.3%; Wistar: 13.7 +/- 3.1% of the soluble 125I) and a linear correlation was observed between the (125I) 3-8 S fraction of the soluble extract and the pronase-resistant fraction. These data suggest that iodocompounds of small molecular size and low turnover accumulate in the thyroid of the Gunn rat due to their strong resistance to in vivo hydrolysis. A local accumulation of 3-8 S iodocompounds may occur within the intracellular dense granules and intraluminal dense masses in the thyroid of Gunn rat.

Animals↗
PubMed2002

Biological significance of proliferation, apoptosis, cytokines, and monocyte/macrophage cells in bone marrow biopsies of 145 patients with myelodysplastic syndrome.

Labeling index (LI), apoptosis, levels of 2 pro-apoptotic cytokines tumor necrosis factor-alpha (TNF-alpha) and transforming growth factor-beta(TGF-beta), and the number of monocyte/macrophage cells that are the likely source of the cytokines were simultaneously measured in plastic-embedded bone marrow (BM) biopsy sections of 145 patients with myelodysplastic syndromes (MDS). TNF-alpha was correlated with TGF-beta (P = .001) and with monocyte/macrophage cells (P = .003). Patients with excess blasts in their marrows had a higher TGF-beta level (P = .01) and monocyte/macrophage number (P = .05). In a linear regression model,TGF-beta emerged as the most significant biological difference between patients who have excess of blasts and those who do not (P = .01). We conclude that in addition to TNF-alpha, TGF-beta also plays a significant role in the initiation and pathogenesis of MDS, and that a more precise definition of its role will likely identify better preventive and therapeutic strategies.

Anemia, Refractory↗
PubMed1991

Dimensional changes in cells and tissues during specimen preparation for the electron microscope.

Studies on dimensional changes incurred during preparation of tissue specimens for the transmission and scanning electron microscopes are reviewed, with emphasis on quantitative measurements pertinent to morphometry and three-dimensional reconstruction. The scope of the review includes fixation, dehydration, plastic embedment, critical-point drying, and freeze-drying. Recommendations are presented for monitoring dimensional changes; a strategy for the choice of method of specimen preparation is outlined.

Artifacts↗