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Biomedical subjects

B Bloch

Publications and source records attributed to B Bloch.

At least 109 records · Page 6Linked to original sources
PubMed1993

Prenatal D1, D1b and D3 dopamine receptor gene expression in the rat forebrain: detection by reverse polymerase chain reaction.

Three dopamine receptor mRNAs were detected by reverse polymerase chain reaction in the rat forebrain during ontogeny. The D1 receptor mRNA gave a faint signal from gestational day 11 (G11) on, while the D1b receptor was not detectable before G12. The D3 receptor mRNA was slightly expressed at G11 and clearly present at G14. Our results show that these mRNAs are present at early stages of fetal life, each one with its specific time of appearance.

Animals↗
PubMed1993

The presence of particles resembling human T-cell leukemia virus type I at ultrastructural examination of lymphomatous cells in a case of T-cell leukemia/lymphoma.

BACKGROUND: Cases of adult T-cell leukemia/lymphoma (ATLL) resulting from human T-cell leukemia virus type I (HTLV-I) have been observed mainly in the southern part of Japan. Recently, the authors performed a second examination of cutaneous, muscle, and nerve biopsy specimens from a French white woman who died of ATLL in 1979. METHODS: A 67-year-old white woman had a lymphoma diagnosed on a lymph node biopsy. She then had acute pains and a thickened skin on both legs. Blood examination showed a leukocyte count of 16,000/ml with 75% leukemia T-cells. Biopsies were performed on the antero-external surface of the right leg. She died after 2 years of illness. RESULTS: Lymphomatous infiltrates of T-cell origin were seen in the dermis, between muscle fibers, and in a peripheral nerve. The recent ultrastructural examination of a few vacuoles located in the cytoplasm of certain lymphomatous cells showed rounded structures mixed with larger virus-like formations having a central nucleoid and spike material around the envelope. Polymerase chain reaction experiments performed on deparaffinized sections demonstrated the presence of a tax sequence homologous to that of HTLV-I. Other structural genes were not detected. CONCLUSIONS: These results contrast with other ultrastructural studies in which HTLV-I was detected only after cultivation of leukemia cells from patients with ATLL. This case probably resulted from an HTLV-I variant.

Aged↗
PubMed1993

Tumor necrosis factor alpha in human kidney transplant rejection--analysis by in situ hybridization.

Macrophagic infiltration and necrosis of rejected kidney transplants represent two pejorative patterns. It has been assumed that the macrophagic toxicity is mediated partly by secretion of tumor necrosis factor alpha. On the other hand, TNF is also involved in many inflammatory and immunological phenomena. We thus evaluated the expression of TNF mRNA by in situ hybridization in 6 rejected kidney transplants using a radiolabeled TNF-c DNA probe. Then the synthesis of TNF alpha protein was studied by immunohistochemistry using an anti-TNF alpha antibody. In severely rejected kidney grafts, TNF mRNA is expressed in some monomorphic infiltrating cells, mostly located in the deepest part of the cortex and around the tubes. These cells do not bind other probes, such as dopa-decarboxylase DNA or preproenkephalin RNA. They are also recognized by a monoclonal antibody directed against TNF alpha. What is more, this antibody binds with some glomerular endothelial and tubular epithelial cells that do not express TNF mRNA. These cells are likely target cells for TNF. In the normal kidney, there are no cells expressing TNF-alpha mRNA.

Gene Expression↗
PubMed1993

Expression of Aleutian mink disease parvovirus proteins in a baculovirus vector system.

We have previously published a detailed transcription map of Aleutian mink disease parvovirus (ADV) and proposed a model for the translation of the two virion structural proteins (VP1 and VP2) and three nonstructural proteins (NS-1, NS-2, and NS-3) (S. Alexandersen, M. E. Bloom, and S. Perryman, J. Virol. 62:3684-3994, 1988). To verify and further characterize this model, we cloned the predicted open reading frames for NS-1, NS-2, NS-3, VP1-VP2, and VP2 alone into a recombinant baculovirus and expressed them in Sf9 insect cells. Expression of VP1-VP2 or VP2 alone in cDNA and in the genomic form was achieved. The expressed proteins had molecular weights similar to those of the corresponding proteins of wild-type ADV-G, although the ratio of VP1 to VP2 was altered. The recombinant baculovirus-expressed ADV VP1 and VP2 showed nuclear localization in Sf9 cells and were able to form particles indistinguishable, by electron microscopy, from wild-type virus. The large nonstructural protein, NS-1, showed predominantly nuclear localization in Sf9 cells when analyzed by immunofluorescence and had a molecular weight similar to that of wild-type ADV NS-1. Moreover, expression of NS-1 in Sf9 cells caused a change in morphology of the cells and resulted in 10-times-lower titers of recombinant baculovirus during infection, suggesting a cytostatic or cytotoxic action of this protein. The smaller NS-2 gene product seems to be located in the cytoplasm. When analyzed by Western immunoblotting, NS-2 comigrated with an approximately 16-kDa band seen in lysates of ADV-infected feline kidney cells. The putative NS-3 gene product exhibited a diffuse distribution in Sf9 cells and had a molecular weight of approximately 10,000. All of the expressed ADV-encoded proteins were recognized by sera from ADV-infected mink. Thus, expression of ADV cDNAs allowed assignment of the different mRNAs to the viral proteins observed during ADV infection in cell culture and supported our previously proposed ADV transcriptional and translational scheme. Moreover, the production of structural proteins from a full-length NS-2 mRNA may add to the repertoire of parvovirus gene expression.

Aleutian Mink Disease Virus↗
PubMed1993

Biotinylated probes for in situ hybridization histochemistry: use for mRNA detection.

Biotinylated probes for in situ hybridization (ISH) are now widely used to detect RNAs and viral genomes at the light and electron microscopic levels. Many protocols for ISH with biotinylated probes are now available. The most critical parameters that influence sensitivity and specificity of the procedure are the nature of the probe, the mode of fixation or incorporation of biotin, and the mode of detection of biotin. Biotin can be detected with antibodies or with avidin (or streptavidin) to which is coupled a marker that can be identified under the microscope. Here we review the protocols, pitfalls, advantages, and disadvantages of biotinylated probes for ISH.

Animals↗
PubMed1992

Expression of the HBNF (heparin-binding neurite-promoting factor) gene in the brain of fetal, neonatal and adult rat: an in situ hybridization study.

HBNF (heparin-binding neurite-promoting factor) and MK (midkine) are members of a newly recognized family of proteins, the expression of which is developmentally regulated. These proteins are expressed highest during fetal development in many tissues but they seem to be rather restricted to the brain in adult animals. Gene expression for these proteins is inducible by retinoic acid in embryonal carcinoma cell lines. They induce neurite outgrowth in cultured neurons, and they are characterized by high sequence conservation between species. While the function(s) of these proteins are unknown, available evidence suggests possible roles in the development and the maintenance of neural tissues. This in situ hybridization study investigates the temporal and spatial expression pattern of the HBNF gene in the brain of developing rats. The HBNF gene is highly expressed in the neuroepithelium and the ependyma from fetal day 15 on. Although most ependymal structures express the gene strongly, a few restricted areas of the ependyma do not express HBNF (ventral part of the fourth ventricle, subcommissural organ). In the brain parenchyma, HBNF is expressed in the thalamo-hippocampal area from fetal day 15 and in the cerebral cortex from fetal day 16, with high expression occurring in the superficial layers of the cortex. The nature of the cells expressing the gene, while difficult to ascertain, is probably glial for the most part. However, certain neurons (in limited areas of the brain parenchyma) and most pial cells (in the meninges), also express the gene. HBNF gene expression decreases sharply a few days after birth. HBNF mRNA is also detectable at fetal days 15 and 16 in the face fetal mesenchyma. In the adult rat brain, the expression of the HBNF gene appears to be restricted to neurons of the hippocampus and of the olfactory bulb and to the superficial layers of the cortex. The structurally related MK gene, though not extensively studied here, shows an entirely different temporal and spatial expression pattern. MK gene is weakly expressed during ontogeny in most brain areas, and in the adult animal, MK mRNA is present only in the choroid plexus. The intense and widely distributed expression of the HBNF gene in several cell populations in the fetus, the progressive spatial and quantitative restriction of HBNF gene expression with brain differentiation, as well as the properties of the protein suggest important and diverse functions for HBNF in cellular interactions and cell differentiation in the developing brain, that must act temporally and spatially by ways distinct from its MK companion molecule.

Amino Acid Sequence↗
PubMed1992

Three cases of primary cerebral lymphoma in AIDS patients: detection of Epstein-Barr virus by in situ hybridization and Southern blot technique.

Three cases of primary cerebral lymphoma in acquired immunodeficiency syndrome were studied. Tumoral fragments taken at autopsy were frozen and studied by the Southern blot technique (SBT). Other tumoral fragments were fixed in formalin, embedded in paraffin and used for in situ hybridization (ISH) with biotinylated probes for DNA of Epstein-Barr virus (EBV). ISH was positive in each case with a spotty nuclear labelling of certain tumoral cells. SBT evidenced a clonal rearrangement of the immunoglobulin heavy chain gene in each case. In addition, EBV DNA was detected in each frozen fragment with only one restriction pattern, indicating that the EBV- infected cell population was a clonal expansion of a progenitor cell.

Adult↗
PubMed1992

Morphological findings on peripheral nerve biopsies in 15 patients with human immunodeficiency virus infection.

A peripheral nerve biopsy was performed in 15 patients with human immunodeficiency virus (HIV) infection and polyneuropathy. Two cases [1 asymptomatic, 1 AIDS-related complex (ARC)] presented with chronic inflammatory demyelinating polyneuropathy; there was 1 case (asymptomatic) of mononeuropathy multiplex and 12 cases (1 asymptomatic, 1 ARC, 10 AIDS) with distal symmetrical polyneuropathy. Epi- or endoneurial microvasculitis was observed in 6 cases. Electron microscopy showed that nerve fiber lesions were mainly axonal. Severe segmental demyelination was also present in both cases of chronic inflammatory demyelinating polyneuropathy, with characteristic features of active demyelination in one. Numerous plasmacytoid cells were found in the endoneurium in 4 patients. Tubuloreticular inclusions were present in endothelial cells in the 10 cases with AIDS but absent in the other patients. Direct immunopathological examination with anti-immunoglobulin sera was negative in all cases. HIV was evidenced by in situ hybridization in 2 AIDS patients; no Epstein-Barr virus or cytomegalovirus was detected.

Adult↗
PubMed1992

Evaluation of the calcium phosphate ceramic implant by non-invasive techniques.

Current routine radiological procedures do not quantify the degree of calcium phosphate ceramic implant integration with the host bone, nor the rate of remodelling processes in the latter. The successful clinical use of non-invasive techniques in assessing bone mass deserves attention from surgeons and scientists dealing with hard tissue prosthetics and implants. Two suitable techniques for such non-invasive sequential analysis of the ceramic implant and host bone are outlined.

Absorptiometry, Photon↗
PubMed1992

Ontogeny of D1 and DARPP-32 gene expression in the rat striatum: an in situ hybridization study.

D1 dopamine receptor (D1R) and DARPP-32 (a dopamine and adenosine 3',5'-monophosphate regulated phosphoprotein), gene expression was studied in the rat striatum in adults and during ontogeny by in situ hybridization. D1R mRNA was first detected in the striatal primordium at day 17 of gestation. At day 18, D1R mRNA was found throughout the striatum. Before birth, the striatal neurons had neuroblastic aspect and were close together, giving homogeneous and compact labelling. After birth, the topography and aspect of the neurons containing D1R mRNA and DARPP-32 mRNA were similar. The two mRNAs were detectable in the caudate-putamen, accumbens nucleus and olfactory tubercle. The microautoradiographic analysis demonstrated that D1R and DARPP-32 genes are massively expressed by the medium-sized striatal neurons. The proportion of medium-sized neurons containing the DARPP-32 mRNA was however higher than that of the neurons containing the D1R mRNA. Furthermore, an unexpected proportion of large-sized neurons express these genes. This proportion varies with development. Comparison between the appearance, topography and frequency of choline-acetyltransferase immunoreactive neurons and large-sized neurons containing D1R or DARPP-32 mRNA suggest that these large-sized neurons containing D1R and DARPP-32 mRNAs are cholinergic ones.

Aging↗
PubMed1992

Reserpine treatment stimulates enkephalin and D2 dopamine receptor gene expression in the rat striatum.

We investigated the effect of catecholamine depletion on gene expression for preproenkephalin A (PPA) and D2 dopamine receptor (D2R) in the rat nigrostriatal complex, using quantitative Northern blot analysis. The D2R probe indifferently recognizes the two mRNA isoforms generated by alternative splicing from the same gene. Short-term and chronic reserpine treatment increase the level of PPA and D2R mRNA in the striatum in a complex manner. For short-term treatment, we injected 10 mg/kg of reserpine the first day, 5 mg/kg 24 h later and sacrificed the rats at various times after the last injection. This treatment resulted in an increase of the level of PPA mRNA by 50% and D2R mRNA up to 150%. For chronic treatment, we injected 0.5 mg/kg of reserpine for 21 days, sacrificed the rats one day after the last injection and observed an increase in PPA and D2R mRNA levels by 100%. Statistical analysis revealed that the PPA mRNA level after chronic treatment was significantly higher from the one obtained after short-term treatment while no such difference was observed for the D2R mRNA. In contrast, reserpine treatment does not modify the level of D2R mRNA in the substantia nigra suggesting that catecholamine depletion has postsynaptic but not presynaptic consequences in the rat nigrostriatal complex. These results demonstrate that reserpine acts at the gene or the mRNA level to induce dopamine supersensitivity in striatal dopaminoceptive neurons.

Animals↗
PubMed1992

Coronavirus infection in mink (Mustela vison). Serological evidence of infection with a coronavirus related to transmissible gastroenteritis virus and porcine epidemic diarrhea virus.

Antibodies to a transmissible gastroenteritis virus (TGEV)-related coronavirus have been demonstrated in mink sera by indirect immunofluorescence, peroxidase-linked antibody assays and immunoblotting. This is the first serological evidence of a specific coronavirus infection in mink. The putative mink coronavirus (MCV) seems to be widespread in the Danish mink population with a prevalence approaching 100%. Analysis by immunoblotting has shown that MCV is closely related to TGEV by the spike (S), matrix (M) and nucleoprotein (N) polypeptides. Furthermore, antibodies to MCV also cross-reacted with N and M polypeptides of porcine epidemic diarrhea virus (PEDV). Thus MCV may occupy an intermediate position between the TGEV group of coronavirus and PEDV. The possibility that MCV may be associated with syndromes of acute enteritis in preweaning mink is discussed.

Animals↗
PubMed1992

Disseminated histoplasmosis in a badger (Meles meles) in Denmark.

We report the first case of disseminated histoplasmosis in an animal in Scandinavia. Yeast cells compatible with those of Histoplasma capsulatum var. capsulatum were found in the skin, liver, spleen, a kidney, and a lymph node of a wild badger (Meles meles). The diagnosis was confirmed by electron microscopy and immunofluorescence staining of the yeast cells in tissue sections.

Animals↗
PubMed1992

Growth hormone-releasing hormone-synthesizing neurons are a subpopulation of somatostatin receptor-labelled cells in the rat arcuate nucleus: a combined in situ hybridization and receptor light-microscopic radioautographic study.

Distribution of growth-hormone-releasing hormone (GHRH) cell bodies and somatostatin binding sites were compared in the mediobasal hypothalamus of the rat. GHRH-synthesizing neurons were visualized by in situ hybridization, using as 35S-labelled synthetic oligonucleotide (45 mere), and 125I-Tyr0-DTrp8-somatostatin (125I-SRIH) binding sites by light-microscopic radioautography on adjacent 20-microns-thick frozen mirror sections. GHRH mRNA hybridizing cells were detected mostly in the ventrolateral portion of the arcuate nucleus (ARC) and around the perimeter of the ventromedial nucleus (VMN). Comparison with the distribution of pericellular 125I-SRIH binding sites allowed to differentiate three types of cells: (1) GHRH perikarya not associated with pericellular 125I-SRIH binding sites around the perimeter of the VMN, (2) 125I-SRIH-labelled cells, not associated with GHRH perikarya in the periventricular zone along the dorsal part of the third ventricle, and (3) in the ventrolateral portion of the ARC, GHRH mRNA-labelled neurons had the same distribution as 125I-SRIH-labelled cells. Furthermore, on adjacent sections, the number of both labelled cells were correlated (r = 0.68; p less than 0.001). In this last population, the extent of colocalization of 125I-SRIH binding sites on GHRH mRNA-labelled neurons was further investigated in adjacent 5-microns-thick sections. The proportions of cells GHRH mRNA and 125I-SRIH allowed to differentiate three subdivisions of the arcuate: the periventricular (PV), ventrobasal (VB) and lateral portions. In the PV-ARC, 27% of GHRH-synthesizing cells were coidentified as 125I-labelled while only 6% of 125I-labelled cells contained GHRH mRNA. In the VB-ARC the proportion of double-labelled cells was equivalent (31 and 26%, respectively for GHRH mRNA and 125I-SRIH).(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1992

Immunohistochemical detection of proluteinizing hormone-releasing hormone peptides in neurons in the human hypothalamus.

To determine the presence of LHRH prohormone products in the human hypothalamus, antisera raised against LHRH and GnRH-associated peptide (GAP) were used to search for the presence of the corresponding antigens in the human adult and fetal hypothalamus by an immunohistochemical approach. The comparison of immunostaining on adjacent sections shows that all of the cells labeled with LHRH antiserum are also labeled with GAP antiserum and vice versa. Labeled cells are detectable during the 9th week of fetal life, this being the earliest time evaluated. At this time, the LHRH/GAP-positive cells frequently have a neuroblastic appearance. The first detectable fibers appear during the 11th week, and these were observed in the lamina terminalis cinerea and median eminence. In the adult brain, fibers and endings labeled with LHRH or GAP antiserum in the median eminence demonstrate the same topography and morphological characteristics, which are distinct from fibers labeled with other neuropeptide antisera. These results show that the LHRH precursor molecule is produced throughout life in the human hypothalamus, including the earliest stages of development of the peptidergic neurons. Moreover, the detection of LHRH- and GAP-positive fibers in the median eminence by the 11th week of fetal life suggests the possibility of an early role of LHRH and, possibly, other LHRH prohormone-derived peptides in the development of anterior pituitary function during the fetal period.

Adult↗
PubMed1992

The natural history of carcinoma of the cervix in young women.

Invasive carcinoma of the cervix was treated in 1,522 patients over a 10-year period at Groote Schuur Hospital. Data for each patient included place of residence, pathological characteristics of the tumour, nodal spread, histological evidence of human papillomavirus (HPV) infection, disease stage, treatment type, treatment complications, site of recurrence and survival time. Patients aged under 35 years comprised 11.6% of the total patient group. A retrospective cohort study compared women aged under 35 years of age at the time of entry into the study and women aged 35 years or more. In all, 82 eligible young patients were compared with random sample of 82 eligible older patients. Contingency tables, life tables and proportional hazards analysis were used where appropriate. There was no significant difference across the two age groups in the incidence of non-squamous tumours, or in the grades of squamous tumours. Similarly there was no evidence of differences in lymph node involvement or HPV infection. Young patients appeared to enter the study at significantly earlier stages of the disease, and a greater proportion of them underwent surgical treatment (diff = 36.4% +/- 13.5%). In both groups treatment complications were less frequently observed after surgery than after radiotherapy. Sites of tumour recurrence were similar in both groups, and there was no apparent difference in survival times.

Adenocarcinoma↗
PubMed1992

5-Lipoxygenase gene expression in the thymus.

Eicosanoids are arachidonic acid metabolites issued both the cyclooxygenase and the lipoxygenase pathways. Many of these products were reported to modulate the immune response. Since most of eicosanoids have a short half life they are considered as local immunomodulators. Interactions between eicosanoids and thymocytes appear to be complex within the thymus. It was reported that cyclooxegenase derivatives of arachidonic acid are produced in this primary lymphoid organ mostly by cells of the thymic microenvironment. On the other hand it is not yet clearly established (1) what is the location of the lipoxygenase-positive cells within the gland and (2) what is the ratio of cells producing lipoxygenase metabolites of arachidonic acid when compared to the whole thymocyte population. Using two oligonucleotides complementary to the rat 5-lipoxygenase mRNA we demonstrated (by both hybridization on Northern blots and in situ hybridization) the expression of the 5-lipoxygenase gene in the thymus. 5-lipoxygenase positive cells appear to be associated in "clusters" and are mostly located in the thymic cortex. It is likely that they belong to the thymic microenvironment.

Animals↗