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Biomedical subjects

B Bloch

Publications and source records attributed to B Bloch.

At least 91 records · Page 5Linked to original sources
PubMed1995

Cervical carcinoma associated with pregnancy.

Because of the uncommon synchronous occurrence of pregnancy and invasive cervical carcinoma, this disease entity remains poorly understood. In addition inconsistent reporting has precluded meaningful meta-analysis. About 1 in 2000 pregnancies are associated with cervical cancer and pregnancy is a complication in approximately 3 percent of patients with cervical cancer. There is little evidence to suggest that the pregnancy has an influence on prognosis. Although not firmly established, vaginal delivery may have an adverse effect on outcome. Timing of delivery must be individualized inasmuch as there is a role for delaying treatment in order to achieve fetal lung maturity. Surgery and radiotherapy should be utilized in the same stage-dependent manner as in nonpregnant patients but management should be individualized and undertaken by a multidisciplinary team. These and other issues are discussed more fully in this review.

Adult↗
PubMed1995

Campylobacter hyointestinalis subsp. lawsonii subsp. nov., isolated from the porcine stomach, and an emended description of Campylobacter hyointestinalis.

The taxonomic relationships of seven isolates obtained from porcine stomachs (the "CHY" group), which resembled (but were distinct from) the type strain and other reference strains of Campylobacter hyointestinalis, were examined by using phenotypic and genomic methods. The phenotypic characteristics and ultrastructure of the new organisms were characteristic of Campylobacter species, although they could be distinguished from all previously described taxa. A numerical analysis of 38 phenotypic characters revealed that the new isolates formed a distinct group at a similarity level of 90.1% and could be clearly distinguished from reference strains representing 20 related taxa, principally species and subspecies belonging to the genera Campylobacter, Arcobacter, and Helicobacter. DNA-DNA hybridization studies revealed that the porcine stomach strains were genomically homogeneous (levels of relatedness, 84 to 90%), although the levels of DNA homology with type and reference strains of C. hyointestinalis were relatively high (56 to 71%). Differences in the DNA base compositions of the CHY group and C. hyointestinalis strains were also observed. Our data indicate that the new porcine isolates should be considered members of a subspecies of C. hyointestinalis, for which we propose the name Campylobacter hyointestinalis subsp. lawsonii subsp. nov. The type strain is strain CHY 5 (= LMG 14432 = NCTC 12901 = CCUG 34538). The description of C. hyointestinalis is emended accordingly, and a description of Campylobacter hyointestinalis subsp. hyointestinalis subsp. nov. is given.

Animals↗
PubMed1995

Does colposcopically directed punch biopsy reduce the incidence of negative LLETZ?

OBJECTIVE: To evaluate the role of punch biopsy in reducing the occurrence of negative histology provided by large loop excision of the transformation zone in the management of cervical intraepithelial neoplasia. DESIGN: Retrospective review of computerised data base and clinic files. SETTING: Colposcopy Clinic, Groote Schuur Hospital, Cape Town, South Africa. SUBJECTS: Two hundred and ninety-eight women considered suitable for the local outpatient management of cervical intraepithelial neoplasia. METHODS: Two groups of patients were identified: group A consisted of women who had cervical intraepithelial neoplasia confirmed colposcopically and who underwent directed punch biopsy; group B consisted of women who had cervical intraepithelial neoplasia confirmed colposcopically and were referred for large loop excision of the transformation zone without confirmatory punch biopsy. RESULTS: In Group A (n = 184) 123 women had cervical intraepithelial neoplasia diagnosed on punch biopsy. Large loop excision of the transformation zone was performed on 116 women and 7 were lost to follow up. The procedure confirmed cervical intraepithelial neoplasia in 95 cases (82%), but there was no cervical intraepithelial neoplasia in 21 cases (18%). Sixty-one women had negative punch biopsies. Of these, 13 underwent large loop excision of the transformation zone, 31 had persistently negative follow up cytology, and 9 had positive cervical smears of which 7 were treated with large loop excision of the transformation zone, and 8 were lost to follow up. Overall, 25% of all negative punch biopsies were falsely negative. In group B 114 were treated with large loop excision of the transformation zone and cervical intraepithelial neoplasia was confirmed in 97 cases (85%); one woman had unsuspected microinvasion (1%) and 16 women (14%) had no cervical intraepithelial neoplasia. Negative histology after large loop excision of the transformation zone was not statistically different in groups A and B. CONCLUSION: Punch biopsy does not reduce the occurrence of negative histology after large loop excision of the transformation zone.

Adult↗
PubMed1995

Primary chemotherapy with bleomycin, ifosfamide and cisplatinum (BIP) followed by radiotherapy in the treatment of advanced cervical cancer. A pilot study.

Bleomycin, Ifosfamide and Cisplatinum were combined in a 3 cycle regime of neoadjuvant chemotherapy given prior to radiotherapy in the treatment of 26 patients with late Stage (FIGO IIB-IIIB) cervical cancer. Seven patients were withdrawn for reasons of compliance and 1 patient due to toxicity. The response rate to chemotherapy in the remainder (18 patients) was 44.4%. Sixtyfour per cent of 17 patients who completed chemoradiotherapy responded completely. This regime was generally well tolerated and neurotoxicity was less problematic than in other reports, although fatal pneumotoxicity occurred in one patient. It is too early to comment on survival; this is an interim report of responses and toxicities. The results are less impressive than in other reported studies and cast doubt on the role of neoadjuvant chemotherapy in the management of advanced cervical cancer in developing countries.

Adult↗
PubMed1995

Peripheral T-cell lymphoma in a chronically immunosuppressed renal transplant patient.

Non-Hodgkin large cell lymphomas occurs more commonly in organ-transplanted patients than in the general population. They are usually of B-cell origin whereas T-cell lymphomas are rare. We report a new case of peripheral T-cell lymphoma in an immunosuppressed renal transplanted patient. The patient presented a hepatosplenic mass with a widespread extension causing serious pancytopenia. It was classified as a pleomorphic medium and large cell type and corresponded to the "common" alpha beta-TCR type lymphoma. Lymphomatous cells exhibited an incomplete mature T-cell phenotype. T-cell receptor gene clonal rearrangement associated with a germline configuration of the immunoglobulin heavy chain gene confirmed a clonal T-cell genotype. By using both Southern blot analysis and polymerase chain reaction, we failed to demonstrate any association with Epstein-Barr virus or human T-cell lymphotropic virus type I or type II.

Adult↗
PubMed1995

Simultaneous development of two different B-cell lymphomas in a patient with acquired immune deficiency syndrome evidenced by molecular analysis.

We report a case of a man positive for the human immunodeficiency virus who rapidly died of lymphoma with cerebral, lung, and pericardic involvement. After autopsy, histopathological study of the different tumor sites showed the same morphological feature of immunoblastic lymphoma, with large areas of necrosis. In situ hybridization showed monotypic kappa light chain mRNA within lung lymphoma cells and monotypic lambda light chain mRNA within cerebral lymphoma cells. Polymerase chain reaction analysis showed two different immunoglobulin heavy chain gene rearrangements for lung and cerebral lymphoma. Here the simultaneous association of two malignant lymphomas derived from different B-cell clones indicates that molecular analysis of different tumor sites can distinguish between dissemination of the same lymphoma and simultaneous proliferation of different malignant B-cell clones.

Acquired Immunodeficiency Syndrome↗
PubMed1995

Use of non-radioactive probes for mRNA detection by in situ hybridization: interests and applications in the central nervous system.

Non-radioactive probes for in situ hybridization (ISH) are now widely used to detect mRNAs in the central nervous system (CNS) using light and electron microscopy. Many different protocols for the detection of biotinylated or digoxigenin-labelled probes are now available. The advantages and inconveniences of the use of the non-radioactive probes are reviewed in the current work. These aspects are illustrated by some results from first-hand experience in the field of ISH to analyse gene expression and neuronal phenotypes in the hypothalamus and the basal ganglia. A very sensitive procedure for the simultaneous detection of two mRNAs with cRNA probes have been detailed and using in particular digoxigenin-labelled probes.

Animals↗
PubMed1994

Prenatal ontogeny of D2 dopamine receptor and dopamine transporter gene expression in the rat mesencephalon.

This work demonstrates the early prenatal expression (by gestational day 14) of dopamine D2 receptor and dopamine transporter mRNAs by immature dopaminergic cells of the rat mesencephalon using in situ hybridization. Our results indicate that mRNAs are detectable 3 days before the appearance of functional D2 presynaptic receptors and detectable dopamine release at striatal terminals.

Animals↗
PubMed1994

Differential influence of haloperidol and sulpiride on dopamine receptors and peptide mRNA levels in the rat striatum and pituitary.

We examined the effect of chronic administration (14 days) of haloperidol (2 mg/kg/day) or sulpiride (100 mg/kg/day), on the mRNA levels of various genes in the rat striatum and pituitary by quantitative in situ and Northern blot hybridizations. In the pituitary, haloperidol and sulpiride induced similar increases of mRNAs of pro-opiomelanocortin (POMC) (+65% and +73%), prolactin (PRL) (+821% and +840%) and growth hormone (GH) (+32% and +47%), but sulpiride induced a greater increase of D2R mRNA (+125%) than haloperidol (+92%). In the striatum, sulpiride and haloperidol had different effects: sulpiride induced a higher increase than haloperidol of both preproenkephalin A (PPA) mRNA (+67% versus +47%) and D2 dopamine receptor (D2R) mRNAs (+72% versus +40%). Moreover, haloperidol and sulpiride had opposite effects on substance P (SP) mRNA. Haloperidol decreased the amount of SP mRNA by 20% while sulpiride increased it by 20%. The D1 dopamine receptor (D1R) mRNA level was not significantly modified after either treatment. Our results demonstrate that the effect of a chronic haloperidol treatment on striatal dopamine receptors and neuropeptide mRNA levels is different to that of sulpiride, whereas it is similar on pituitary hormones mRNA levels.

Animals↗
PubMed1994

Expression of polyadenylated and non-polyadenylated trkC transcripts in the rodent central nervous system.

We have previously isolated a full-length cDNA clone encoding rat TrkC, a member of the Trk family of tyrosine kinase receptors, that specifically mediates biological responses to neurotrophin-3. Here, we report the identification of five major trkC transcripts in the adult and developing rat and mouse brain suggesting the presence of several TrkC receptors. Northern blot hybridizations revealed that three of these trkC transcripts (of 14, 3.9 and 4.8 kb) were poly(A)+ messenger RNAs, while the two others, of shorter size (1.1 and 0.7 kb), were poly(A)- messenger RNAs. All transcripts were expressed in 11 brain regions but poly(A)- messenger RNAs were found at much higher levels than poly(A)+ messenger RNAs in the cerebellum. Hybridization with five oligonucleotide and two complementary DNA probes, corresponding to different parts of the full-length trkC complementary DNA, revealed that the two poly(A)- transcripts may encode for receptors truncated in their extracellular and kinase intracellular domains. During ontogeny, poly(A)- trkC messenger RNAs were found at low amounts at prenatal and early postnatal ages with a drastic increase in the cerebellum at postnatal day 30. No poly(A)- transcript was identified for the trk B gene. In situ hybridization revealed that trkC messenger RNAs are expressed both in granular and Purkinje cells in the cerebellum. Northern blot on RNA extracted from mice mutant strains with degeneration of either granular or both granular and Purkinje cells suggested that poly(A)- and poly(A)+ trkC messenger RNAs are expressed within the same cells. We have demonstrated the existence of several trkC transcripts that differ both by their size and polyadenylation. This phenomenon could be of physiological relevance in regulating TrkC functions. To the best of our knowledge, this is an original feature for a mammalian gene expression. Studies focused on poly(A)- messenger RNAs could give rise to the identification of other genes expressed in a similar fashion.

Animals↗
PubMed1994

Delta-opioid receptor gene expression in the mouse forebrain: localization in cholinergic neurons of the striatum.

Opioid peptides and opioid receptors, particularly the delta receptor, are abundant in the striatum where they contribute to the neuronal interactions, and are involved in various behavioral effects. The recent cloning of the delta-opioid receptor now allows the identification of the striatal neurons that express it, and that are direct targets of endogenous opioid peptides such as enkephalins. In this context, we have used in situ hybridization histochemistry to determine the distribution of the delta-opioid receptor messenger RNA in the forebrain, and especially the phenotype of the neurons expressing the delta-opioid receptor gene in the striatum. We show that the topgraphy of the neurons containing the delta-opioid receptor messenger RNA is similar to the topography of the neurons containing the choline acetyltransferase messenger RNA in the mouse forebrain. Comparison of adjacent serial sections demonstrates that the delta-opioid receptor gene is indeed expressed exclusively in cholinergic interneurons in the striatum. As these neurons also selectively express the substance P receptor gene, our data suggest that the striatal cholinergic interneurons are a common link in the interactions between the two striatal efferent populations, namely enkephalin and substance P neurons.

Animals↗
PubMed1994

Production of mink enteritis parvovirus empty capsids by expression in a baculovirus vector system: a recombinant vaccine for mink enteritis parvovirus in mink.

The VP-2 gene of mink enteritis parvovirus (MEV) was amplified by the polymerase chain reaction using MEV DNA isolated from the faeces of a naturally infected mink. Subsequently the VP-2 gene was cloned into a baculovirus expression vector. Recombinant baculoviruses were isolated and the MEV VP-2 gene product was characterized after expression in Sf9 insect cells. The MEV VP-2 product had the same size as that reported for the wild-type MEV VP-2 protein and was recognized by convalescent sera from MEV-infected mink and a panel of monoclonal antibodies reactive to MEV. Furthermore, the VP-2 protein was able to form parvovirus-like particles, which had haemagglutinating properties comparable with the wild-type MEV. The cloned VP-2 gene was sequenced and only five nucleotide differences were found after alignment with the known sequences of the MEV type 1 and type 2 isolates. Surprisingly, the VP-2 gene encoded a valine and a tyrosine at amino acid positions 232 and 234, identical to the situation found in MEV type 1, but at position 300 there was a valine which is a determinant of MEV type 2. Immunization of mink with approximately 40,000 haemagglutinating units of recombinant MEV VP-2 induced a measurable antibody response as tested by haemagglutination inhibition. Furthermore, the immunized mink did not excrete virus and did not develop clinical disease upon challenge with a virulent isolate of MEV.

Animals↗
PubMed1994

Osteogenesis imperfecta in Holstein-Friesian calves.

Eight calves with osteogenesis imperfecta were born in a Danish Holstein-Friesian herd during a two-year period. In total 92 calves were born (84 normal), and all were sired by a clinically normal Holstein-Friesian bull. The defect was probably due to a de novo dominant mutation present as a gonadal mosaicism in the bull. Affected calves were characterised by multiple fractures, congenital bone deformations, general joint laxity, dentinogenesis imperfecta, and light blue sclerae. The skin seemed normal. Electron microscopical studies revealed slightly decreased average diameter of cutaneous collagen fibrils, while the diameter of collagen fibrils in tendons and ligaments was severely reduced. Abnormalities of collagen type I from skin and compact bone were not detected by biochemical analyses.

Animals↗
PubMed1993

Fos immunoreactivity after stimulation or inhibition of muscarinic receptors indicates anatomical specificity for cholinergic control of striatal efferent neurons and cortical neurons in the rat.

Cholinergic neurons play a major role in the control of striatal activity via muscarinic receptors. The action of acetylcholine also appears to be dependent on the striosome-matrix compartmentalization of the striatum. This study was designed to find out whether modification of acetylcholine tone activates neurons in the striatum and forebrain of the rat. We looked for the appearance of immunoreactivity to Fos, a regulatory protein that is thought to convert synaptic signals into changes in gene expression. Pharmacological manipulation of muscarinic receptors was found to induce specific patterns of Fos immunoreactivity in distinct neuronal populations of the forebrain, including the striatum. Oxotremorine, a non-selective muscarinic agonist, induced Fos immunoreactivity in the striatum with a large predominance in striosomes (mostly in enkephalinergic neurons), in layers 4 and 6 of the cortex, and also in the piriform cortex and septum. The muscarinic agonist pilocarpine had an identical effect in the cortex, but the striosomal prevalence was less clear-cut than that observed after oxotremorine. Treatment with dopamine-depleting agents (6-hydroxydopamine or reserpine) and inhibitors of glutamate and opiate receptor (MK-801 and naloxone respectively) had no effect on the action of oxotremorine. This suggests that the induction of Fos provoked by oxotremorine does not involve dopamine, glutamate or opiates. Atropine, a non-specific muscarinic antagonist, also induced Fos immunoreactivity in the striatum but with matrix predominance (mostly in substance P neurons), as well as in the cingulate cortex, and the olfactory tubercle. Scopolamine, a muscarinic antagonist, induced Fos in both striosomal and matrix compartments in the striatum.(ABSTRACT TRUNCATED AT 250 WORDS)

Acetylcholine↗