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PubMed1977

Paranasal sinuses of the adult buffalo (bubalus bubalis).

In addition to sinus conchalis, four paranasal sinuses; sinus frontalis, sinus lacrimalis, sinus maxillaris and sinus palatinus have been found to occur in adult buffalo. The sinus sphenoidalis was not noticeable, whereas all other paranasal sinuses were well developed. The sinus frontalis in buffalo differs from that in ox, in that, in buffalo it does not involve any part of os-temporale; its sinus frontalis caudolateralis subdivided by the septum sinuum frontalium transversus rostralis; another transverse septum, the septum frontalium transversus caudalis separates the sinus frontalis from its diverticulum nuchale; the diverticulum nuchale is much more extensive due to well developed os parietale in this species than in ox and is further subdivisible into four subcompartments. The sinus lacrimalis, sinus maxillaris and sinus palatinus do not present much appreciable differences from those in ox. The topographic description of all the compartments, diverticulae, septae and communication of the paranasal sinuses in buffalo has been presented. The most suitable site of trephining the sinuses has been suggested.

Animals↗
PubMed1995

[Seasonal variation in the ultrastructure and calcium uptake rate of cardiac sarcoplasmic reticulum in ground sqirrel].

The ultrastructure and calcium uptake rate of the cardiac sarcoplasmic reticulum (SR) was quantatively compared between the ground squirrels (Citellus dauricus) in hibernating and non-hibernating season. (1) In our ultrastructural investigation, OsFeCN post-fixation method was used to enhance the staining of SR, which made the SR structure more recognizable. (2) The results of morphometrical analysis demonstrated that the volume density of SR and lipid droplet in the cardio-myocyte was significantly higher (P < 0.01) in the hibernating animal than in the summer active one, and the subcompartment of SR with this difference was non-junctional SR. (3) The cardiac SR from hibernating ground squirrels had a higher (P < 0.01) calcium uptake rate as measured by the absorbence of arsenazo-III Ca2+ indicator, than that from autumn active ones. Altogether, our results suggested that the function of SR in the uptake of cytosolic calcium was enhanced in hibernating season, which may play an important role in the cold tolerance of myocardium of a hibernator.

Animals↗
PubMed1996

Stereologic study of splenic tissue compartments from traumatically injured and cancer patients.

Carefully age-matched groups of patients, surgically treated for either traumatic injury (n = 5; mean = 71.2 years) or for early stage carcinoma (n = 5; mean = 74.2 years), were used to investigate all the splenic tissue compartments applying model-based stereology. The point-counting method was utilized to study the volume densities of following tissue compartments: red pulp, perifollicular zone, white pulp (this compartment was divided into two subcompartments: follicles and periarteriolar lymphatic sheath), marginal zone and connective tissue. The following stereologic parameters of lymphoid follicles were determined: areal numerical density (the number of follicles per mm2 of tissue section), the numerical density (number of follicles per mm3 of tissue), and the mean follicle diameter. The identity of tissue compartments was verified using immunohistochemical staining for B- and T- lymphocytes. Significantly increased volume densities of perifollicular zone and periarteriolar lymphatic sheath were registered in patients treated for traumatic spleen injury. On the other hand, the significantly increased number of lymphoid follicles per mm2 and per mm3 of splenic tissue were registered in the group of cancer patients. The differences observed, whether attributable to the immune stimulation of the ruptured spleen or the alterations of the immune system due to malignant disease, suggest that this issue deserves further attention.

Aged↗
PubMed1996

Stereological study of tissue compartments of the human spleen.

Morphometric reports on animal and human spleen are very few and no studies have been carried out using stereological methods to investigate all of the tissue compartments of the human spleen. Eighteen samples of spleens, which were either surgically removed after traumatic injury or during treatment for early stage carcinoma or gastric ulcer, were investigated. The point-counting method was used to study the volume densities of the following tissue compartments: red pulp, perifollicular zone, white pulp (this tissue compartment was divided in two subcompartments: follicles and periarteriolar lymphatic sheath), marginal zone and connective tissue of trabeculas. The following stereological parameters of the follicles were investigated: the number of follicles per mm2 of spleen section, numerical density, volume density, and the mean follicular diameter. The identity of spleen tissue compartments was verified using immunohistochemical staining for B- and T-lymphocytes. The volume densities of tissue compartments, as well as stereological parameters of lymphoid follicles, were similar in both groups of splenic samples, except for the volume densities of perifollicular zone and periarteriolar lymphatic sheath, where a statistically significant difference was registered.

Animals↗
PubMed1996

Time course of vinblastine-induced autophagocytosis and changes in the endoplasmic reticulum in murine pancreatic acinar cells: a morphometric and biochemical study.

The time course of the vinblastine(-sulfate; 10 mg/kg body weight, single injection)-induced enlargement and subsequent regression of the autolysosomal compartment was studied by electron microscopic morphometrical and cell biochemical methods in order to gain information concerning some key problems of this major route of intralysosomal degradation of the cell's endogenous macromolecules and structures. Detailed analysis of the dynamics of the total autophagic vacuole (AV) compartment and its different subcompartments (early, advanced, late, and fused AVs), as well as of changes of rough-surfaced endoplasmic reticulum (RER) showed: 1. Pancreatic acinar cells react to vinblastine biphasically, i.e. two expansion phases of the AV compartment, the first in the 0 to 90 min and the second in the 2 to 8 h post-injectional periods, were detected. 2. Fusions of AVs are not inhibited by vinblastine, at least during the second expansion phase when cytoplasmic volume fraction (CVF) of fused AVs steadily increased until the 12th h. Fusion of early, advanced and late AVs or composition of fused complex vacuoles (AVc) are somehow regulated, as the proportion of the three AV stages from the CVF of AVc, was maintained constant throughout the second expansion phase. 3. Stimulation of autophagosome formation and resulting substrate overload seems to be the primary mode of action by which vinblastine causes the enormous expansion of the autolysosomal compartment. 4. Degranulation of the rough-surfaced endoplasmic reticulum (RER) membranes occurs in a biphasic fashion, similarly to the volume and surface changes of the AV compartment, thus supporting our previous hypothesis, that labilization or change of RER may have a role in the formation of autophagosomes. 5. Vinblastine-induced autophagocytosis is a selective process, as mitochondria, Golgi elements and zymogen granules are very much underrepresented, whereas RER is more than twice overrepresented in the volume of early AVs, when compared to their volume fraction in the whole cytoplasm. 6. Immunogold electron microscopy revealed the presence of ubiquitinylated proteins in advanced and late, but not in early AVs.

Animals↗
PubMed1997

Modular organization of occipito-temporal pathways: cortical connections between visual area 4 and visual area 2 and posterior inferotemporal ventral area in macaque monkeys.

The modular organization of cortical pathways linking visual area 4 (V4) with occipital visual area 2 (V2) and inferotemporal posterior inferotemporal ventral area (PITv) was investigated through an analysis of the patterns of retrogradely labeled cell bodies after injections of tracers into V4 and PITv. Although cytochrome oxidase or other stains have failed to yield reliable independent anatomical markers for cortical modules beyond V1 and V2, V4 and PITv seem to have modular compartments with specific patterns of cortico-cortical connectivity. Tracer injections of V4 labeled cells in V2 (1) thin stripes exclusively, (2) interstripes exclusively, or (3) specific combinations of interstripe and thin stripe subcompartments. These labeling patterns suggest (1) that there is a complicated organization of inputs to V4, (2) that projections from V2 to V4 display a submodular selectivity, and (3) that projections from V2 to V4 display some degree of cross-stream convergence. Consistent with this framework, extensive regions of PITv provide feedback projections to interstripe-recipient portions of V4, whereas more restricted portions of PITv provide feedback to thin stripe-recipient portions of V4. Similarly, the feedforward projection from V4 to PITv often arose from multiple cell clusters across a wide expanse of V4. When distinguishable fluorescent tracers were injected into two PITv sites separated by 3-5 mm, a variety of projection patterns was observed in V4. In most cases, labeled cells were found in multiple, interdigitating, nonoverlapping clusters of 1-3 mm width, whereas in other cases the two labeled fields were highly intermixed. These results suggest that V4 and PITv contain functional modules that can be characterized by the specific patterns of segregated and convergent projections they receive from lower cortical areas. These specific patterns of intercortical input, in conjunction with intrinsic cortical circuitry, may endow extrastriate cortical neurons with new and more complex receptive field properties.

Animals↗
PubMed1997

The human ALL-1/MLL/HRX antigen is predominantly localized in the nucleus of resting and proliferating peripheral blood mononuclear cells.

The ALL-1 gene is an important regulator of embryonal and hematopoietic development, and structural variants of the human gene generated by chromosomal translocations and other genomic alterations presumably act as oncogenes in the pathogenesis of acute leukemias and other hematological malignancies. Antisera against two different epitopes of the human ALL-1 protein (anti-ALL1-N and anti-ALL1-C) were produced. Both sera revealed indistinguishable patterns of antigen localization in human peripheral blood mononuclear cells (PBMCs). In resting PBMCs, the antigen was distributed in a speckled pattern across the nuclei, with an increased density at the nuclear envelope and the nuclear indentation. In mitotically stimulated PBMCs, the antigen surrounded the condensing chromosomes but did not colocalize with chromatin or the nuclear scaffold. The antigen is considered a marker for a novel nuclear subcompartment, a perichromosomal area termed the "chromosomal envelope." In Western blot experiments, the anti-ALL1-N serum reacted with a polypeptide corresponding to the expected full-length 430-kDa ALL-1 protein. Recombinant proteins representing the AT-hook and zinc binding subdomains of the ALL-1 protein interacted in vitro with a degenerate mixture of double-stranded oligodeoxynucleotides. Thus, the ALL-1 protein probably is a DNA-binding protein with both a sequence-unspecific (AT-hook) and a sequence-specific (zinc binding subdomains) double-stranded DNA binding mode.

Animals↗
PubMed1997

Stereological study of splenic tissue compartments in FK506-treated rats.

Model-based stereology was used to study the changes of splenic structure and proportions of splenic tissue compartments in FK506-treated male Wistar rats (0.1 mg/kg three times a week for 14 days). The point-counting method was utilized to study the volume densities of the following tissue compartments: red pulp; white pulp (this compartment was divided in two subcompartments: follicles and periarteriolar lymphocyte sheath); marginal zone; and connective tissue. The following stereological parameters of lymphoid follicles were also determined: areal numerical density (the number of follicles per mm2 of tissue section); the numerical density (number of follicles per mm3 of tissue); and the mean follicle diameter. After FK506 treatment a significant reduction of volume density of white pulp was observed, which was due to the very prominent decline in the amount of periarteriolar lymphocyte sheath, whereby the cellular density of this tissue compartment was decreased. In the marginal zone of FK506-treated spleens the presence of numerous, large, densely packed lymphoblastic cells of very uniform appearance was registered. These observations are in very good keeping with the changes of splenic morphology registered in cyclosporin A-treated rats, which further documents the parallelism in actions between these immunosuppressive agents.

Animals↗
PubMed1997

MHC class II compartments: specialized organelles of the endocytic pathway in antigen presenting cells.

Mounting an immune response against foreign, extracellular material requires that this material be internalized by antigen presenting cells, processed to peptide fragments and then displayed on the cell surface for recognition by the T cell receptor on T helper cells. Such peptides, derived from internalized antigens are generally presented to T cells in association with Major Histocompatibility Complex (MHC) class II molecules. Recent work has identified subcompartments of the endosomal/lysosomal system that appear to be important sites for the generation of peptide-MHC class II complexes. These so-called MHC class II compartments receive antigenic fragments from endosomes and lysosomes and load them onto class II molecules. From these compartments, peptide-loaded class II molecules are transported to the plasma membrane, where they can trigger T cells bearing appropriate receptors. This review summarizes recent work characterizing MHC class II compartments as specialized organelles of the endosomal/lysosomal pathway. Interestingly, MHC class II compartments share many features common to organelles present in a wide variety of specialized cells with quite different functions. Modifying the endocytic pathway to serve the needs of specialized cells may be a common mechanism which allows very different cell types to carry out their disparate functions.

Animals↗
PubMed1998

1,25-Dihydroxyvitamin D3 protects human leukemic cells from tumor necrosis factor-induced apoptosis via inactivation of cytosolic phospholipase A2.

The mechanism by which tumor necrosis factor (TNF) induces death of cancer cells appears to involve the activation of cytosolic phospholipase A2 (cPLA2). U937 human leukemic cells treated with 1,25-dihydroxyvitamin D3 [1,25(OH)2D3; 10(-8) M] become resistant to TNF, an effect that is independent of cell cycle status and expression of TNF receptors or BCL-2. In this study, TNF produced a dose- and time-dependent enhancement of [3H]arachidonic acid release in U937 cells. The amount of [3H]arachidonic acid release was positively associated with TNF-induced apoptosis. Both immunofluorescence microscopy and Western blotting of cell subcompartments demonstrated translocation of cPLA2 from the cytosol to the cell membrane in response to TNF. In addition, TNF up-regulated expression of cPLA2 mRNA. An antisense oligonucleotide to cPLA2 and the cPLA2 inhibitor 4-bromophenacyl bromide significantly inhibited TNF-induced cytotoxicity. Prior incubation of cells with 1,25(OH)2D3 significantly inhibited (a) TNF-induced [3H]arachidonic acid release and apoptosis, (b) TNF-induced translocation of cPLA2 to the membrane, and (c) the up-regulation of cPLA2 mRNA with TNF. Furthermore, the inhibitory effect of 1,25(OH)2D3 was not reversed by inhibitors of transcription or translation. The data suggest that activation of cPLA2 is involved in TNF-induced apoptosis of leukemic cells. 1,25(OH)2D3 directly inhibits cPLA2 translocation and mRNA up-regulation induced by TNF. Disruption of cPLA2 activation may represent a possible mechanism whereby leukemic cells can become resistant to TNF-mediated killing.

Apoptosis↗