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PubMed2003

[Intracellular localization of XCAP-E protein in XL2 (Xenopus laevis) cells under normal conditions and during inhibition of pRNA transcription and processing].

The interaction of condensin subunit XCAP-E with various nucleolar subcompartments in XL2 cells was studied. In the interphase cells, XCAP-E was associated with a granular component of nucleoli (as shown by double staining with antibodies against B23) and with small nucleolus-like structures in the nucleoplasm. Inhibition of transcription by actinomycin D does not disrupt interaction of XCAP-E with the granular compartment of segregated nucleoli. Treatment with DRB 5,6-dichloro-1 beta-ribofuranozide-benzimidazole causes disintegration of nucleolar fibrillar complexes, but does not affect nucleolar localization of XCAP-E. The data suggest that nucleolar association of XCAP-E is independent on the functional state of the nucleolus, and imply a possible role of this protein in rRNA processing and pre-fibosome assembly.

Animals↗
PubMed2003

Viruses as hijackers of PML nuclear bodies.

Promyelocytic leukemia nuclear bodies (PML-NBs) are discrete interchromosomal macromolecular structures. The integrity of this dynamic nuclear subcompartment critically depends on the presence of the name-giving PML protein. Among the permanent or transient residents of PML-NBs are various regulatory proteins, including Sp100, CBP, pRb, HIPK2, RAD51 and p53. PML-NBs are frequently targeted by viral infections, as a number of different RNA and DNA viruses, including herpesviruses, adenoviruses, papovaviruses, papillomaviruses and arenaviruses, cause changes in PML-NBs. Viruses interfere with PML-NB in two ways: 1) some viral proteins can associate with PML-NB proteins and/or lead to the destruction and lysis of this subnuclear compartment, thus aiding viral gene expression and disabling the host's innate immunity; 2) the parental genomes of some nuclear-replicating DNA viruses associate preferentially with PML-NBs, which presumably serves to assist in viral gene expression or replication. Here we feature the different viral strategies leading to the hijacking of PML-NBs and discuss the consequences for the immune response.

Animals↗
PubMed1992

Red blood cell partitioning of gallopamil, verapamil and norverapamil.

In-vitro binding of calcium-antagonists gallopamil and verapamil (and its main metabolite norverapamil) to human red blood cells (RBCs) was investigated. The drugs are bound reversibly and dose dependent to RBCs in the same order of magnitude, with partition-coefficients of kRBC = 0.12-0.34 for gallopamil, kRBC = 0.10-0.30 for verapamil and kRBC = 0.10-0.27 for norverapamil. The data indicate that, although RBCs may act as subcompartments of the blood for this class of compounds, they may have no influence on therapeutic plasma concentrations, due to their low kRBC.

Biological Availability↗
PubMed2004

[Identification of novel PSD proteins and their possible functions].

There are a number of mRNA species localizing to dendrites of neuronal cells, and a postsynaptic local translation system may allow local and rapid synthesis of key postsynaptic proteins required for expression of synaptic plasticity. Most mRNAs localizing in the postsynaptic region may be translated into postsynaptic proteins, localizing in the postsynaptic subcompartments, such as PSD, the synaptic plasma membrane (SPM), or the cytoplasmic region of the spines or dendrites. However, there appears to be a number of dendritic mRNAs (Dems) and postsynaptic proteins still to be found. Recently, we developed a method to identify a large number of mRNA species associated with PSD fraction (Tian et al (1999) Mol Brain Res, 72: 147-157). During the identification process of these mRNAs, we cloned several full-length cDNAs, such as a synaptic short form LDL receptor-related protein (ssLRP) (Tian et al (2002) Soc Neurosci Abst, 28: 405), synaptic ubiquitin-specific protease (synUSP), TANC (a protein containing tetratricopeptide repeat [TPR], ankyrin repeat, and coiled-coil domain) (Suzuki et al (2003) Soc Neurosci Abst, 29), and so forth. In situ hybridization and immunochemical studies confirmed dendritic localization of mRNAs for these proteins in dendrites, and the localization of these proteins in postsynaptic regions, respectively. Some proteins contained signals for targeting the PSD and interacted with various PSD proteins. We present properties and possible physiological functions of these proteins and report the recent progress in our project to identify a large number of postsynaptic proteins based on the identification of dendritically localizing mRNAs.

Guanine Nucleotide Exchange Factors↗
PubMed1992

Monensin and brefeldin A differentially affect the phosphorylation and sulfation of secretory proteins.

Chromogranin B and secretogranin II, two members of the granin family, are known to be post-translationally modified by the addition of O-linked carbohydrates to serine and/or threonine, phosphate to serine and threonine, and sulfate to carbohydrate and tyrosine residues. In the present study, chromogranin B and secretogranin II were used as model proteins to investigate in which subcompartment of the Golgi complex secretory proteins become phosphorylated. Monensin, a drug known to block the transport from the medial to the trans cisternae of the Golgi stack, inhibited the phosphorylation of the granins, indicating that this modification occurred distal to the medial Golgi. Monensin also blocked the addition of galactose to O-linked carbohydrates and the sulfation of the granins, confirming previous data that these modifications take place in the trans Golgi. To distinguish, within the trans Golgi, between the trans cisternae of the Golgi stack and the trans Golgi network, we made use of the previous observation that brefeldin A results in the redistribution to the endoplasmic reticulum of membrane-bound enzymes of the trans cisternae of the Golgi stack, but not of the trans Golgi network. Brefeldin A treatment abolished granin sulfation but resulted in the accumulation of phosphorylated and galactosylated granins. Differential effects of brefeldin A on membranes of the Golgi stack versus the trans Golgi network were also observed by immunofluorescence analysis of marker proteins specific for either compartment. Our results suggest that the phosphorylation of secretory proteins, like their galactosylation, largely occurs in the trans cisternae of the Golgi stack, whereas the sulfation of secretory proteins on both carbohydrate and tyrosine residues takes place selectively in the trans Golgi network.

Animals↗
PubMed2005

Relationship between body composition changes and changes in physical function and metabolic risk factors in aging.

PURPOSE OF REVIEW: Several body composition changes are known to occur with aging. The purpose of this review is to evaluate recent literature examining body composition changes with aging and how these relate to changes in physical function and metabolic risk. RECENT FINDINGS: Cross-sectional and longitudinal studies have observed increases in fat mass and decreases in muscle mass or lean tissue mass in older adults, often in the absence of differences or changes in body weight. Cross-sectional studies have also reported increases in intramyocellular lipid and liver fat in older versus younger adults and related changes in body composition with changes in physical function and metabolic risk, but few longitudinal data are available. Furthermore, most longitudinal studies lack precise methods of assessing body fat distribution and muscle and organ quality, resulting in a lack of detailed and precise information on body composition changes with aging and their relationship to health. SUMMARY: Research to date has outlined a need for more detailed body composition measurements of aging adults. Absence of change in a total body compartment may mask a change in subcompartments that may impact health. Furthermore, intervention studies to determine ways to maintain body composition are consistent with healthy living throughout the aging process.

Adipose Tissue↗
PubMed1991

Time course of neutral red-induced autophagy in murine pancreatic acinar cells. A morphometrical and cytochemical study.

The knowledge of the time course of the influences of chemicals on autophagy is of great importance in the study of their modes of action and hence provides information relating the mechanism and dynamics of this catabolic process. Neutral red (NR) treatment has long been used to produce an accumulation of autolysosomes in different cell types. In the present study early (AV1), advanced (AV2) and late (AV3), as well as complex (fused) AVs (AVc) were distinguished. In our morphometrical measurements, we found all these AV subcompartments significantly expanded as early as 30 min after the injection of NR (0.4 mg/g b.wt.), i.e. a large number of AVs accumulated in the cells. Since cytoplasmic volume fraction (CVF) of AV increased 3-fold during this early period we conclude that, unlike vinblastine, NR is not a fusion inhibitor. Accumulation of AV1 (3-fold) in the presence of fusions possibly indicates that NR stimulates formation of AVs in this early period, after the accumulation of AVs continued. The maximal CVF of AVs were measured at 4 h, when 7.6% of the cytoplasmic volume was sequestered into the AV compartment, two third of which came from AV3. This finding indicates that NR is probably an inhibitor of intravacuolar degradation. However, the high rate of accumulation of AV2, AV3, and total AVs including a slower but still pronounced accumulation of AV1 cannot be explained solely from inhibition of degradation, but indicates a stimulated segregation (AV formation). Our results therefore argue for a possible coupling of the regulation of autophagic segregation and degradation since vinblastine and possibly some other degradation inhibitors were also found to stimulate AV formation in other studies. Another goal of this study was to follow the time course of changes in distribution of certain lysosomal enzymes after NR treatment. According to our enzyme cytochemical studies, acid phosphatase (AP) of untreated cells is mainly located in large and small lysosomal elements of the Golgi zone, aryl sulfatase B (AS) in trans-Golgi elements including pre-secretory granules and trimetaphosphatase (TP) in basal lysosomes. After NR injection TP seemed to appear first in AV1 whereas AP activity was characteristic of more advanced AVs. AS activity only occasionally appeared in AV3 and exclusively at late times after NR injection.

Acid Anhydride Hydrolases↗
PubMed1991

Presence of terminal N-acetylgalactosamine residues in subregions of the endoplasmic reticulum is influenced by cell differentiation in culture.

Using Helix pomatia lectin as a specific probe for terminal, nonreducing N-acetylgalactosamine residues, glycoprotein precursors bearing newly initiated O-linked oligosaccharides have been localized in the lumen of the endoplasmic reticulum and cis-Golgi cisternae. This pattern contrasts with the detection of the terminal disaccharide galactose beta-1,3-N-acetylgalactosamine by Arachis hypogaea lectin in middle and trans-Golgi compartments, which are considered elongation sites for O-glycosylation. Distribution of H. pomatia ligands in the endoplasmic reticulum is confined to specialized regions or subcompartments in both human colonic adenocarcinoma cells and cultured chicken chondrocytes. Since in cartilage, chondrocytes contain H. pomatia-binding sites exclusively concentrated in cis-Golgi cisternae, primary cultures of this cell type have been used to study those conditions that promote initiation of O-glycosylation in the endoplasmic reticulum. A correlation has been found between the age of the culture and the extent of reactivity of the endoplasmic reticulum with either H. pomatia lectin or antibody against the sequence GalNAc alpha-serine/threonine (Tn antigen). Cells showing an extensive reaction are not hindered in their secretory activity and still maintain the chondrocyte phenotype. Taken together the results suggest that the intracellular distribution of the glycosylation enzymes is not only cell type-specific as previously shown (Roth, J., Taatjes, D. J., Weinstein, J., Paulson, J. C., Greenwell, P., and Watkins, W. M. (1986) J. Biol. Chem. 261, 14307-14312) but it might also vary depending on the stage of cell differentiation.

Acetylgalactosamine↗
PubMed1990

Cytochemical and immunocytochemical study on the peroxisomes of rat liver after administration of a hypolipidemic drug, MLM-160.

After administration of a hypolipidemic drug, MLM-160, to male rats, liver peroxisomes were studied by biochemical, cytochemical, and immunocytochemical methods. The activities of D-amino acid oxidase, glycolate oxidase, and urate oxidase increased 2 to 3-fold by the treatment. The increase of the oxidases was confirmed by immunoblotting analysis. By light microscopy, immunoreaction for catalase was present in the cytoplasmic granules of hepatocytes. The stained granules formed some clusters and overlapped each other after MLM-160 treatment. However, immunostaining for D-amino acid oxidase and urate oxidase was present in discrete fine granules which did not overlap each other. By electron microscopy, many peroxisomes showed ring-like extensions and cavitation of the matrix, often giving the appearance of a peroxisome-within-a-peroxisome. In many cases, these unusual peroxisomes seemed to be interconnected with each other. Within the peroxisomes, the catalase was localized in the matrix. Urate oxidase was associated with the crystalloid cores. D-amino acid oxidase was localized focally in a small part of the matrix where the catalase was mostly negative. In conclusion, the administration of MLM-160 to male rats induces some peroxisomal oxidases, accompanying the appearance of unusual peroxisomes. The precise localization of peroxisomal enzymes suggested that there are subcompartments within the liver peroxisomes as shown in rat kidney peroxisomes.

Animals↗
PubMed1990

An ultrastructural morphometric study of follicular center lymphocytes: III. The control of lymphocyte nuclear size in reactive hyperplasia and non-Hodgkin's lymphoma.

Since lymphocyte nuclear size and shape play such a key role in the classification of non-Hodgkin's lymphoma (NHL), the mechanisms and nuclear compartments responsible for the control of nuclear size are of fundamental importance to pathologists. To assess the role of condensed chromatin and the interchromatinic region of the nucleus in determining the size of this organelle, morphometric image analysis of total nuclear area and the area occupied by these two compartments was performed on electron micrographs of nuclear profiles from lymphocytes in lymph node biopsies of four cases of reactive lymphoid hyperplasia and ten examples of NHL. Using bivariate linear regression analysis, it was clear that, whether in normal mantle zone and follicular center lymphocytes or in the neoplastic lymphocytes of various NHLs, there is an extremely high correlation (R = 0.96) between the size of the interchromatinic region and the area of nuclear profiles. In contrast, there is a poorer correlation (R = 0.63) between the area occupied by condensed chromatin and nuclear area. The results demonstrate for the first time that even in NHL, where some nuclear features clearly vary from the normal counterpart, the control of nuclear size continues to be largely dependent on a particular subcompartment of the nucleus, the interchromatinic region. How this fact influences the categorization of subtypes of NHL for therapeutic and prognostic purposes will be an essential avenue for further investigation.

Cell Nucleus↗
PubMedDate not supplied

Cell growth in chronic myeloid leukemia at blast crisis.

During the stage of blast crisis, the increase in the population of peripheral blasts in one examined untreated CML patient, obeyed an exponential equation of growth that requires a maintained equal proportion of proliferating to quiescent blasts. A model of cell growth at CML blast crisis is presented, which interprets the required constancy of equal-size blast subcompartments in terms of regulation of the G0----G1 flow, the latter involving activation of one cell out of three interacting quiescent blasts in contact. This model is discussed in the light of evidence that G0 blast activation involves membrane-bound interacting sites interfering with growth-promoting pathways. The model-predicted proliferative index (f) value of 0.5 +/- 0.16 is found to be nearly identical to a reported estimate of the 3H-thymidine-labeling index of CML blasts at the crisis stage of the disease. It is also close to corresponding indexes of CML blood and marrow progenitor cells and to labeling indexes of AML and ALL large blasts.

Blast Crisis↗
PubMed1989

P-glycoprotein expression in plasma-cell myeloma is associated with resistance to VAD.

Tumor cell-associated expression of multidrug resistance (MDR) was quantitated in 22 patients with DNA-aneuploid myeloma using 2-parameter flow cytometry with monoclonal antibody (MoAb) C-219 for the detection of cytoplasmic p-170 and propidium iodide for nuclear DNA content. The proportion of cells expressing p-170 and the intensity of p-170-related fluorescence were determined for each patient. Among the 14 patients treated with vincristine-adriamycin-dexamethasone (VAD), the proportion of p-170-positive cells distinguished sensitive from resistant disease (P less than .01). Among a subgroup of seven patients with MDR analysis available prior to VAD therapy, two subsequent nonresponders had high proportions of C-219-reactive cells. The presence de novo of high proportions of p-170-expressing cells in another still untreated patient and in a further individual with resistance to dexamethasone and interferon (not associated with MDR) warrants systematic analysis of p-170 expression prior to therapy to determine its clinical implications for response to MDR-associated drugs as combined in the VAD regimen. Concurrent MDR expression by aneuploid tumor cells and cells in the diploid subcompartment may represent involvement of diploid cells in the myeloma disease process.

ATP Binding Cassette Transporter, Subfamily B, Mem↗
PubMedDate not supplied

Flow cytometry in clinical oncology: cell cycle and DNA ploidy in assessing tumor behavior.

The basic principles of flow cytometry with special emphasis to cell cycle analysis and DNA ploidy measurements are described. The concept of separation of various subcompartments of cell cycle, distinguished by simultaneous determinations of DNA versus RNA and DNA versus protein contents is presented. Based on DNA ploidy patterns, human tumors were divided into two groups designated as diploid range and non-diploid (aneuploid). Since it has been proposed that diploid range tumors have generally better prognoses than non-diploid tumors, the value of DNA ploidy patterns as a prognostic factor is discussed in major groups of human cancers.

Animals↗
PubMed1988

Ultrastructural autoradiographic localization of exogenous arachidonic acid in cultured endothelial and smooth muscle cells.

The uptake and intracellular localization of exogenous arachidonic acid (AA) were investigated in cultured endothelial (EC) and smooth muscle cells (SMC) isolated from bovine aorta. The [14C]AA uptake was assessed biochemically and by light and electron microscopic autoradiography. The highest values of silver grain surface density were associated with the mitochondria, lysosomes, and the Golgi apparatus of the EC. The grain linear density was greater on the nuclear envelope than on plasmalemma. On SMC, the grain density was highest on lipid droplets whereas the linear densities of the nuclear envelope and plasmalemma were similar. The share of each subcellular compartment in the AA distribution was estimated as the percentage of the individual silver grain count out of the total cell-associated radioactivity. The results showed that cytoplasm (including endoplasmic reticulum, ribosomes, and small vesicles) made the main contribution followed by the nucleus and at lower values by other organelles. These subcompartments may represent the intracellular sites from which AA could be mobilized for prostanoid synthesis by EC and SMC.

Animals↗
PubMed1988

A novel in vitro assay for murine haematopoietic stem cells.

Study of the biology of haematopoietic stem cells is crucially dependent on the availability of suitable in vitro assays. Existing assays have suffered from the fact that they detect small subcompartments of the total stem cell compartment. This limits experiments where it is required to assay a high proportion of stem cells, e.g. the enumeration of stem cell numbers under varying conditions or the identification and purification of stem cell regulators. We describe an in vitro assay which shows macroscopic colony formation and limited self-renewal capacity in vitro. The detected cell (CFU-A) has a low cycling status in normal bone marrow (NBM) and responds to known stem cell regulators. The incidence (100-200 per 10(5) in NBM), the proliferative characteristics under stress and some of the physical properties are similar to stem cells detected by colony formation after transplantation into lethally irradiated recipients (CFU-S). These data indicate that our assay detects a high proportion of haematopoietic stem cells in vitro. This will facilitate experiments on stem cell behaviour which have previously been difficult to conduct.

Animals↗
PubMed1986

Anatomical variations in the first extensor compartment of the wrist. A clinical and anatomical study.

We studied 300 wrists from cadavera and the wrists of forty patients with de Quervain disease to determine the variation in the pattern of the tendons and septa in the first extensor compartment. In 75 per cent of the wrists from cadavera, we found that the number of tendons within the compartment differed from what is considered standard; there was complete or partial septation in 40 per cent. In about a third of the specimens from cadavera, the first extensor compartment was divided by a septum and two tendons or more were present within the major subcompartment. These features might readily result in inadequate decompression of the compartment in the treatment of de Quervain disease. In our prospective study of forty patients with de Quervain disease, septation was found in twenty-seven. There was no significant difference between the number of patients and the number of specimens from cadavera that had no, one, or two accessory abductor tendons.

Cadaver↗
PubMed1986

RCA I-binding patterns of the Golgi apparatus.

The distribution in the Golgi apparatus of binding sites for the galactose-specific Ricinus communis I lectin (RCA I) was studied in differently specialized cells, including goblet cells and absorptive enterocytes of the rat small intestine as well as acinar cells of the rat embryonic pancreas and submandibular gland. For the purpose of localizing the binding reactions, a pre-embedment method using horseradish peroxidase for electron microscopic visualization, and a post-embedding technique making use of the colloidal gold system were employed. The reactions obtained, localizing cell constituents which contain saccharides with terminal or internal beta-D-galactosyl residues, labeled diverse Golgi subcompartments. The goblet cells showed intense RCA I staining of the cisternae of the trans side of the Golgi stacks. The reaction was weak in the medial cisternae and the cis side of the stacks mostly was devoid of label. In the absorptive cells, in addition to the RCA I reaction of trans Golgi elements, binding sites for this lectin were concentrated in the stacks' medial section. In the embryonic acinar cells, accessible galactosyl residues were either confined to the trans and/or medial cisternae, or distributed across elements of all the stacked saccules. In the latter stacks, the reactions mostly were weak in the cis cisternae and increased in intensity towards the trans side. As regards the respective labeling patterns, similar percentages were calculated for the early and late stages of development: they were approximately 62% for the pattern which showed RCA I label limited to trans/medial cisternae and approximately 38% for the "cis-to-trans"-distributed RCA I reaction.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1979

Antibodies against pluripotent stem cells: their use in studying stem cell function.

The biologic characteristics and specificity of rabbit anti-mouse brain (RAMB) serum for pluripotent hemopoietic stem cells (CFU-s) is reviewed. The application of RAMB serum to the functional analysis of stem cell differentiation and self renewal characteristics is discussed. Preliminary data are presented which suggest the existence of two stem cell subcompartments. The majority of stem cells express membrane determinants that are detected by RAMB serum. A minor (5%-10%) stem cell subpopulation lacks the stem cell antigen and exhibits a greater self-renewal capacity than those cells expressing the antigen.

Animals↗