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Biomedical subjects

B Bloch

Publications and source records attributed to B Bloch.

At least 163 records · Page 9Linked to original sources
PubMed1988

Analysis of vasopressin gene expression by in situ hybridization and immunohistochemistry in semi-thin sections.

We have designed a procedure to investigate vasopressin (AVP) gene expression on plastic-embedded tissue by using in situ hybridization to detect AVP mRNA and immunohistochemistry to detect AVP. Rat brain was fixed and vibratome slices were incubated with a 45-base synthetic oligonucleotide complementary to AVP mRNA labeled with 35S, embedded in Araldite, and cut into semi-thin serial sections that were either processed for autoradiography or treated with an AVP antiserum. The results show that AVP mRNA is detectable in magnocellular neurons of the supraoptic and paraventricular nuclei in both vibratome and semi-thin sections. Osmication after hybridization does not modify the signal. AVP mRNA is restricted to the cytoplasm of magnocellular neurons and to the proximal portion of certain processes. Neurons labeled with the AVP probe were also stained with the AVP antiserum. AVP mRNA quantity and the intensity of AVP immunoreactivity are not consistently related in neurons. At least two hypotheses must be considered to explain these differences: first, the procedure presently used could lead to a reaction intensity that does not exactly reflect the amount of antigen or mRNA present in cells; second, the difference observed may reflect the fact that transcriptional and translational events are not constantly linked and can be regulated differently from one AVP neuron to another. This method provides a way to detect mRNA on semi-thin sections together with antigenic molecules and to accurately investigate gene expression in complex tissues with optimal histological quality.

Animals↗
PubMed1988

Histological detection of messenger RNAs with biotinylated synthetic oligonucleotide probes.

We achieved histological detection of the messenger RNAs coding for vasopressin, calcitonin, or calcitonin gene-related peptide by using biotinylated synthetic oligonucleotides, and defined the technical parameters enabling optimal detection of these mRNAs. Oligonucleotides labeled by fixation of one biotin at their 5' end or by addition of a biotin-11-dUTP tail at their 3' end can be used to detect mRNAs, although the latter are more sensitive. Streptavidin-alkaline phosphatase revealed with nitroblue tetrazolium-bromo-chloro-indolyl phosphate as substrate makes possible detection of the biotinylated oligonucleotides. Increasing formaldehyde concentration in the fixative decreases the signal intensity; 1% formaldehyde fixation provides the most intense signal. Several controls, including those with addition of unlabeled oligonucleotides to the hybridization buffer, confirm the specificity of mRNA detection. The sensitivity of the biotinylated probes is identical or lower as compared to the corresponding radiolabeled oligonucleotides. Histological and subcellular resolution is greatly enhanced with biotinylated probes. The rat vasopressin probes stain magnocellular neurons in the supraoptic and paraventricular nuclei and, under optimal conditions, parvocellular neurons in the suprachiasmatic nucleus. Vasopressin mRNA is present in the cytoplasm of the cell bodies and in the roots of certain processes. Calcitonin and calcitonin gene-related peptide mRNA are found co-localized in the cytoplasm of the same tumor cells in human medullary thyroid carcinoma.

Animals↗
PubMed1987

Anatomical study of enkephalin gene expression in the rat forebrain following haloperidol treatment.

The effect of haloperidol treatment on preproenkephalin A (PPA) gene expression in the rat forebrain was anatomically studied by using an in situ hybridization procedure. The PPA mRNA was detected in sections of control rats and of rats having received an i.p. injection of haloperidol for 14 or 21 days. Sections were incubated with rat PPA cDNA labeled with 32P or 35S, exposed with X-ray film and dipped in Ilford K-5 emulsion. The results showed that haloperidol treatment did not modify the number of cells expressing the PPA gene in the caudate-putamen, the nucleus accumbens, the septum and the olfactory tubercle. In contrast, the PPA mRNA content was increased in the neurons of the caudate-putamen and nucleus accumbens, but unchanged in other areas. These results demonstrate that haloperidol acts by increasing PPA mRNA content selectively in striatal neurons already expressing the PPA gene.

Animals↗
PubMed1987

Human papillomavirus and the squamous epithelium of the female genital tract.

The evidence linking human papillomavirus (HPV) infection with cervical intra-epithelial neoplasia (CIN), cervical cancer and similar changes in the vulval and vaginal epithelium is reviewed. Reference is made to prevalence rates for HPV and CIN in South Africa and South West Africa/Namibia and the prospect of an 'epidemic' of cervical and possibly of other squamous genital cancers is discussed. Only an effective cytological screening programme with effective follow-up arrangements will prevent this; these should be priorities for future preventive medicine strategies.

Epithelium↗
PubMed1987

Transferrin gene expression in choroid plexus of the adult rat brain.

Transferrin immunoreactivity and transferrin messenger RNA (mRNA) were recently found to be present in oligodendrocytes of the adult rat brain by using immunohistochemistry and in situ hybridization procedure. The present study demonstrates, in the same way, that epithelial cells of the choroid plexus also contain transferrin together with transferrin mRNA. Choroid plexus of the lateral and the third ventricle are rich in transferrin mRNA, while choroid plexus of the fourth ventricle contain few if any transferrin mRNA. These results demonstrate that epithelial cells of the choroid plexus as well as oligodendrocytes express the transferrin gene in the adult rat brain.

Animals↗
PubMed1987

Modulation of tyrosine hydroxylase gene expression in the central nervous system visualized by in situ hybridization.

A rat tyrosine hydroxylase [TyrOHase; tyrosine 3-monooxygenase; L-tyrosine, tetrahydropteridine:oxygen oxidoreductase (3-hydroxylating); EC 1.14.16.2] cDNA probe was used for in situ hybridization studies on histological sections through the locus coeruleus, substantia nigra, and the ventral tegmental area of the rat brain. Experimental conditions were established that yielded no background and no signal when pBR322 was used as a control probe. Using the tyrosine hydroxylase probe, we ascertained the specificity of the labeling over catecholaminergic cells by denervation experiments and comparison of the hybridization pattern with that of immunoreactivity. The use of 35S-labeled probe enabled the hybridization signal to be resolved at the cellular level. A single injection of reserpine into the rat led to an increase of the intensity of the autoradiographic signal over the locus coeruleus area, confirming an RNA gel blot analysis. The potential of in situ hybridization to analyze patterns of modulation of gene activity as a result of nervous activity is discussed.

Animals↗
PubMed1987

Demonstration of bovine viral diarrhoea virus in peripheral blood mononuclear cells of persistently infected, clinically normal cattle.

Peripheral blood mononuclear cells (PBL) from cattle known to be persistently viraemic with bovine viral diarrhoea virus (BVDV) following a foetal infection, were examined for the presence of viral antigens and cell-associated infectious virus. Using immunocytochemical techniques, physical separations of PBL subsets and virus isolation techniques (directly and by cocultivation) it was found that infection occurred in B and T lymphocytes, monocytes, and a group of cells designated null cells for lack of more specific classification. The latter three groups also supported viral replication, as infectious virus could be isolated from enriched cell populations. BVDV-like particles in cytoplasmic vesicles of PBL subsets were detected by electron microscopy.

Animals↗
PubMed1987

Medroxyprogesterone acetate in non-metastatic gestational trophoblastic disease.

The effect of medroxyprogesterone acetate (MPA: Depo-Provera, Upjohn) as a contraceptive agent was assessed in 45 patients with non-metastatic gestational trophoblastic disease and compared with 13 patients using hormonal and 26 patients using non-hormonal methods of contraception. In the whole group of 84 patients 18 (21.4%) required chemotherapy. There was no statistically significant difference in the incidence of persistent trophoblastic disease between MPA (9/45) and the oral contraceptive group (2/13) and MPA and the non-hormonal contraceptive groups (7/26).

Adolescent↗
PubMed1987

[Contribution of immunocytochemistry to the study of the development of neuroglandular peptidergic systems in the human fetal hypothalamus].

Immunohistochemistry makes possible the in situ detection of neuropeptides in the cell bodies were they are synthesized, in the fibers that carry them, and in endings. Immunohistochemistry appears necessary to identify and map peptidergic neurons and to study their ontogeny. From 1975, we have carried the immunohistochemical study of several hypothalamic neuronal populations in the human fetus: LH-RH (1976), somatostatin (1977), pro-opiocortin (1978), vasopressin and oxytocin (1979), corticoliberin (1982), somatocrinin (1983), and hypothalamic neurons containing an unidentified peptide (1984). Comparative ontogenetical studies have also been performed in rats.

Animals↗
PubMed1986

Detection of the mRNA coding for enkephalin precursor in the rat brain and adrenal by using an 'in situ' hybridization procedure.

The messenger RNA coding for preproenkephalin A (PPA) has been detected in tissue sections of the rat brain and adrenal by using two rat PPA cDNAs labeled with 32P or 35S as probes. In the brain, neurons were labeled in areas known to correspond to sites of synthesis of enkephalins, including the caudate-putamen, the nucleus accumbens, the olfactory cortex, the hypothalamus, the brainstem and the granular layer of the cerebellum. The presence of the PPA mRNA in the normal rat adrenal medulla shows transcription of the PPA gene in such cells despite the absence of enkephalin immunoreactivity in them. These results demonstrate in situ hybridization as an efficient technique to detect the site of synthesis of PPA.

Adrenal Medulla↗
PubMed1986

In situ hybridization histochemistry for the analysis of gene expression in the endocrine and central nervous system tissues: a 3-year experience.

We report our experience in development of the in situ hybridization (ISH) procedure to detect messenger RNAs (mRNAs) coding for various molecules involved in endocrine glands and central nervous system activity, including mRNAs coding for endorphin precursors [preproenkephalin A (PPA), pro-opiocortin (POMC)], vasopressin, and transferrin. Various conditions of fixation and handling of the tissues were tested to establish optimal parameters for mRNA detection. Double-stranded DNA probes labeled by nick translation, synthetic oligonucleotides labeled at their 5' end, as well as single-stranded RNA probes were used, after incorporation of 32P- or 35S-labeled nucleotides. Specific requirements for efficient and reproducible ISH investigations are discussed. Cells expressing the PPA gene in the adrenal medulla and in the brain were detected by ISH. The results show that ISH is as sensitive as immunohistochemistry in detecting peptide-producing cells in the adrenal and that it allows detection of PPA cell bodies in brain in conditions in which they are inconstantly detected by immunohistochemistry. Unilateral destruction of substantia nigra provokes a dramatic decrease in the number of neurons expressing the PPA gene in the contralateral striatum. Cells expressing the POMC gene were detected in the pituitary of various species including man and in the rat arcuate nucleus. Neurons containing vasopressin mRNA were visualized in the supraoptic paraventricular and suprachiasmatic nucleus of the adult rat by using a synthetic oligonucleotide probe. Transferrin gene expression was shown in the central nervous system of the rat brain in two cell populations, the oligodendrocytes and the epithelial cells of the choroid plexus, by demonstration of simultaneous presence in them of transferrin immunoreactivity together with transferrin mRNA. These results show that the ISH procedure is a technique that can be routinely used to investigate gene transcription anatomically in complex heterocellular tissues such as the endocrine glands and the nervous system.

Adrenal Medulla↗
PubMed1986

Gestational trophoblastic disease: the significance of vaginal metastases.

Five patients with gestational trophoblastic disease whose presenting symptom was hemorrhage from vaginal metastases have been added to our previous report. The clinical features, management, and responses to treatment are outlined. All the patients required suturing of the bleeding lesions under general anesthetic to arrest the hemorrhage. In addition one patient needed selective arterial embolization. This did not compromise the response to chemotherapy. We confirm our previous view that the presence of vaginal metastases should be classified as a high-risk factor and that these patients be treated with multiple agent chemotherapy from the outset.

Adult↗
PubMed1986

Microhysteroscopy in evaluation of the endocervix in endometrial carcinoma.

Microhysteroscopy (MH) was used for the assessment of endocervical involvement in patients with endometrial carcinoma. Between 1 July 1984 and 28 February 1985, fifteen cases were seen. Of these, nine patients had had fractional curettage and all were deemed to have endocervical involvement. As a result of the use of MH, five of these stage II cases were down-staged. The remaining four cases had their staging confirmed by MH and directed endocervical curettage. The six patients who had no initial endocervical assessment were found to have Stage I disease, using the MH alone. The MH findings were corroborated and confirmed on histological examination of the surgical specimens. MH should be the initial investigation in patients with suspected endometrial carcinoma and all patients with postmenopausal bleeding.

Adult↗
PubMed1986

The use of concomitant chemotherapy and radiotherapy prior to surgery in advanced stage carcinoma of the vulva.

Six cases of primary advanced squamous carcinoma of the vulva were treated with concomitant chemotherapy and radiotherapy (C + RT). In five patients it was given in preparation for surgery. The radiation was delivered to the whole pelvis in 10 equal daily fractions of either 2.0 or 2.5 Gy. Mitomycin C (10 mg/m2) was given on Day 1, and 5-fluorouracil (1,000 mg/m2) was given daily from Days 1 to 4, inclusive. All six patients had satisfactory early tumor response. Three patients received one course of C + RT and three were given two courses. One patient died suddenly of unknown causes 6 days after completing the C + RT. One patient with fixed groin nodes was treated with palliative intent. She maintained a complete local response but died 6 months later of liver metastases. The remaining four patients underwent surgery without healing complications and are alive with no evidence of disease at 1, 4, 14, and 26 months. In our experience vulval carcinomas can be reduced in size and extent by prior chemotherapy and radiotherapy and require less extensive surgery.

Adult↗
PubMed1986

The value of cancer antigen-125 as a tumor marker in malignant germ cell tumors of the ovary.

The value of cancer antigen-125 (CA-125) as a tumor marker for malignant germ cell tumors (MGCT) of the ovary was investigated and compared with the other recognized tumor markers (human chorionic gonadotrophin (hCG), alpha-fetoprotein (AFP), carcinoembryonic antigen (CEA) and lactate dehydrogenase (LDH) isoenzymes. In the 10 months following June 1984, 4 new cases with MGCT and 1 patient with active disease on treatment were evaluated. In all cases prior to planned surgery the levels of CA-125 were significantly elevated. The serum values ranged from 154 to 617 U/ml (normal less than 20 U/ml). In 1 case (pure dysgerminoma) CA-125 was the only tumor marker. In 3 patients (2 mixed germ cell tumors and 1 immature teratoma) serum LDH (LD 1, 2, and 3) was elevated, and AFP was elevated in 1 of these. In the fifth case (mixed germ cell tumor), on treatment, serum AFP was used to monitor the disease. Four patients underwent cytoreductive surgery followed by combination chemotherapy. The changes in the serum levels of CA-125 paralleled those of the other tumor markers while on therapy. In our experience CA-125 is an invaluable indicator of the clinical status of the patient and could be a new tumor marker in patients with MGCT.

Adolescent↗
PubMed1986

Immunohistochemical evidence that growth hormone-releasing factor (GRF) neurons contain an amidated peptide derived from cleavage of the carboxyl-terminal end of the GRF precursor.

Antisera were raised against synthetic replicates of the carboxyl-terminal (C-terminal) fragment of the precursor to human GH-releasing factor (GRF) (pre-proGRF) whose structure was predicted from the complementary DNA cloned from a pancreatic tumor. These antisera were used along with antisera to human GRF itself to search for the presence of related molecules in the human hypothalamus, with an immunohistochemical approach. The antisera to pre-proGRF that recognize specifically the C-terminal amidated form of pre-proGRF stain GRF neurons in their cell bodies, fibers, and nerve endings that are in contact with portal capillaries of the median eminence. Antisera against the nonamidated form of the molecule did not give any staining in the hypothalamus. These results strongly suggest that human hypothalamic GRF derives from a precursor immunologically related (and probably identical) to the tumorous one and that this precursor is cleaved inside GRF cell bodies to give, in addition to the GRF-44-NH2 a second amidated peptide, the C-terminal pre-proGRF that is transported distally to nerve endings and most probably coreleased with GRF into portal capillaries.

Adult↗