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Biomedical subjects

G Martin

Publications and source records attributed to G Martin.

At least 325 records · Page 18Linked to original sources
PubMed1987

[Neuromeningeal hypodermyiasis complicated by hydrocephaly. Value of nuclear magnetic resonance imaging].

A 9-year old country boy developed blepharitis with inflammation of the face and, 1 month later, eosinophilic meningitis with paralysis of 3 limbs and of an abducent nerve. Nuclear magnetic resonance imaging of the central nervous system disclosed a lesional signal beneath the floor of the 4th ventricle, which was compatible with the presence of a larva of fly. Treatment with thiabendazole was tried, and the clinical signs regressed. Six months later, an asymmetrical hydrocephalus due to obstruction of Monroe's foramen by an inflammatory granuloma was discovered. Human hypodermyasis, due to migration in tissues of larvae of flies, is not rare in cattle-breeding areas. Neuromeningeal disorders are observed in 12% of the cases, consisting of eosinophilic meningitis sometimes associated with neurological deficit or seizures. Such complications as intracerebral haematoma or meningeal haemorrhage may occur during the usually benign course of the disease.

Child↗
PubMed1987

Immunochemical and immunocytochemical studies of the crustacean vitellogenesis-inhibiting hormone (VIH).

Immunochemical investigations, using dot immunobinding assay (DIA) and enzyme-linked immunosorbent assay (ELISA), and immunocytochemical studies reveal the following new information about crustacean vitellogenesis-inhibiting hormone (VIH): (1) The structure of VIH is sufficiently different from that of the other sinus gland neuropeptides to allow a selective recognition of VIH by polyclonal antibodies. (2) From immunochemical criteria, VIH does not seem strictly species specific. The antisera raised against VIH of Homarus americanus cross-react with sinus gland extracts of Palaemonetes varians, Palaemon serratus, Macrobrachium rosenbergii, Carcinus maenas, and Porcellio dilatatus. (3) In the sinus gland of H. americanus, VIH immunoreactivity is localized mainly in electron-dense granules of medium size (110-185 nm in diameter) while, in P. dilatatus, the labeling is mostly on the largest granules (200-270 nm in diameter).

Animals↗
PubMed1987

Endothelium-dependent relaxation in isolated human arteries and veins.

1. The role of the endothelium in mediating relaxation to acetylcholine, the calcium ionophore A23187, vasoactive intestinal peptide and peptide histidine methionine was studied using isolated human blood vessels. 2. Segments of renal, colic, pulmonary, uterine, transverse cervical, brachial, coronary and coeliac branch arteries, and saphenous veins, were obtained from surgical resection material for use in tissue bath studies. 3. Acetylcholine or A23187 produced endothelium-dependent relaxation in isolated vessels from all vascular beds studied. Coronary arteries, however, differed in their response to acetylcholine which produced predominantly a contractile response, either alone or after initial relaxation. 4. Vasoactive intestinal peptide and peptide histidine methionine produced endothelium-dependent relaxation in coeliac branch arteries. However, these peptides relaxed isolated pulmonary arteries independently of endothelium. 5. Endothelium-dependent relaxation in response to acetylcholine and A23187 was antagonized by nordihydroguaretic acid, a lipoxygenase inhibitor, and methylene blue and haemoglobin, inhibitors of soluble guanylate cyclase. In these respects the endothelium-dependent responses of human arteries to acetylcholine and A23187 resemble those described in other species.

Acetylcholine↗
PubMed1987

No evidence for a direct vasodilatory effect of celiprolol on human vasculature in vivo or in vitro.

Celiprolol is reported to be a new cardioselective beta blocker with novel ancillary properties including vasodilator effects. The purpose of this study was to investigate whether celiprolol possesses a direct vasodilatory effect on human vasculature in vivo and in vitro. We studied the in vivo effects of intra-arterial celiprolol (1-100 micrograms/min i.a.) on forearm blood flow (FBF). Forearm blood was measured by venous occlusion plethysmography. Possible vasorelaxant actions of celiprolol on human vascular smooth muscle were studied using segments of isolated human saphenous vein in vitro. The effect of celiprolol was investigated on resting tone or noradrenaline induced tone. Possible alpha 2-adrenoceptor antagonist effects of celiprolol were assessed using celiprolol as an antagonist of BHT933 induced constriction. Celiprolol was without significant effect on FBF and failed to relax isolated saphenous vein segments preconstricted with noradrenaline. The weak alpha 2-adrenoceptor antagonist action of celiprolol was demonstrable in human saphenous vein. This study does not provide evidence for a direct vasodilatory effect of celiprolol on human vasculature.

Adrenergic beta-Antagonists↗
PubMed1987

The actions of calcitonin gene related peptide and vasoactive intestinal peptide as vasodilators in man in vivo and in vitro.

1 The two peptides calcitonin gene related peptide (CGRP) and vasoactive intestinal peptide (VIP) produced marked dilatation of the forearm vascular bed when infused via the brachial artery. 2 CGRP relaxed preconstricted segments of human radial, coronary, gastric and cerebral arteries in an endothelium dependent manner. 3 VIP relaxed human gastric and transverse cervical arteries in an endothelium dependent manner, but relaxation of the human pulmonary artery was not dependent on endothelium. 4 The characteristics of the endothelium dependent relaxation of these medium-sized muscular arteries indicated involvement of the endothelium derived relaxing factor in vitro. 5 Caution is expressed in drawing comparisons between the mechanisms involved in the in vivo and in vitro vascular responses.

Adult↗
PubMed1987

Principles in mass screening for breast cancer.

The only proven means to reduce mortality from breast cancer is detection of the disease when it is still localized to the breast. Such a cancer is usually without signs or symptoms and often not even palpable and can be detected only through mass screening. The H.I.P. study has demonstrated a 30% reduction in mortality in a randomized study group compared to a matched control. The reduction has persisted over 14 years of follow up. Questions of potential hazard from x-ray radiation, questionable significant benefit in women under 50 years, cost and motivation are discussed.

Breast Neoplasms↗
PubMed1987

[Equilibrium angioscintigraphic evaluation of sequential changes in right ventricle function in patients with lower myocardial infarct and ischemic co-involvement of the right ventricle: long-term study].

The purpose of this study was to define the sequential changes in global and regional right ventricular function, using equilibrium gated radionuclide angiography, following transmural inferior myocardial infarction (IMI) and associated ischemic right ventricular involvement. 24 patients with IMI underwent radionuclide angiography within 72 hours of onset of chest pain; subsequent studies were done at 13 +/- 5 days and at 6 +/- 2 months. Scintigraphic evidence of ischemic right ventricular involvement was defined by depression of right ventricular ejection fraction (less than 40%) and regional wall motion abnormalities (hypo-a-dyskinesia of right ventricular free wall). Significant improvement of global right ventricular ejection fraction was observed in 15 patients at the second study, and in 21 patients at the third study. Right ventricular regional wall motion showed similar improvement from the initial to the final studies. Significant changes in right ventricular function occurred without concurrent changes in global and regional left ventricular ejection fraction. We concluded that patients with IMI and ischemic right ventricular involvement show frequently improvement of global and regional right ventricular function over time. This changes tend to occur early and without significant modifications in left ventricular function. The good prognosis observed in our patients, despite the high incidence of in hospital complications, might be related to the improvement of right ventricular function.

Adult↗
PubMed1986

Interleukin-3-dependent expression of the c-myc and c-fos proto-oncogenes in hemopoietic cell lines.

Using Northern blot analysis the expression of several proto-oncogenes was studied in established lines of mast cell precursors. Upon removal of interleukin-3 (IL-3) from the culture medium, factor-dependent cells stop dividing. During the first 7 h, however, normal amounts of total cellular mRNAs are maintained, and this is reflected in unchanged levels of several transcripts, such as actin, c-Ha-ras and c-fes. In contrast, within 1.5 h of IL-3 removal, the levels of c-myc and c-fos mRNAs decrease drastically and addition of IL-3 at that stage quickly induces back the levels found in actively growing cultures. In factor-independent cells, which proliferate actively even in the absence of IL-3, high levels of c-myc and c-fos transcripts are maintained in the absence of growth factor. In cells arrested by serum starvation, addition of 10% serum induces massive amounts of c-fos transcripts, but not of c-myc, and cell proliferation is not restored. The data suggest that the c-myc and c-fos proto-oncogenes play an important role in mediating the multiple effects of IL-3 on hemopoietic progenitor cells.

Actins↗
PubMed1986

Isolation and sequence of cDNA clones coding for the precursor to the gamma subunit of mouse muscle nicotinic acetylcholine receptor.

cDNA libraries have been constructed in plasmid (pBR322) and bacteriophage lambda gammagt10) vectors with poly (A+) RNA isolated from the nonfusing mouse muscle cell line BC3H-1. The libraries were screened with a restriction fragment derived from a genomic clone coding for a human acetylcholine receptor gamma subunit. Several clones were obtained whose cDNA inserts possessed nucleotide and deduced amino acid sequence homology with acetylcholine receptor gamma subunits from Torpedo californica, chick, calf, and human. One isolate, lambda BMG419, has 88 nucleotides of 5'-untranslated sequence, an open reading frame of 1,557 nucleotides coding for the precursor to the mouse acetylcholine receptor gamma subunit, and 144 nucleotides of 3'-untranslated sequence. Alignment of the lambda BMG419-deduced amino acid sequence with homologs from other species predicts a precursor peptide of 519 amino acids and a mature protein of 497 amino acids, with nonglycosylated molecular weights of 58,744 and 56,424 daltons, respectively. Comparison of the deduced amino acid sequence of the mouse gamma subunit with Torpedo, chick, calf, and human sequences showed overall homologies of 54%, 67%, 90%, and 90%, respectively; however, significantly higher homologies were found in several putative functional domains. Radiolabeled lambda BMG419 has been used to identify homologous RNA species, one of approximately 2 kb and one of about 3.5 kb, in poly (A+) RNA prepared from BC3H-1 cells and denervated mouse limb muscle. gamma Subunit-coding RNA species are considerably more abundant in denervated than in innervated muscle, suggesting that neural regulation of the abundance of the gamma subunit is exerted through regulation of the amount of its mRNA.

Animals↗