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Biomedical subjects

M A Blank

Publications and source records attributed to M A Blank.

70 records · Page 4Linked to original sources
PubMed1979

[Hybridization analysis of the viral sequences in the DNA of a hamster Rous sarcoma].

The nuclear genome of Syrian hamster virrion non-producer tumor contains the Rous sarcoma virus-specific nucleotide sequences. The information complexity of the proviral DNA from its tumor is similar to that for the DNA of Rous chicken sarcoma. The proviral DNA both in the hamster and chicken tumor consists of moderately reiterated and unique sequences. The avian oncornavirus-specific sequences are absent in the DNA of normal hamster tissue.

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PubMedDate not supplied

The distribution and origin of VIP in the spinal cord of six mammalian species.

The distribution of VIP-immunoreactivity was studied in the spinal cord and dorsal root ganglia of 6 mammalian species. Immunoreactive fibres and cell bodies were most apparent in the dorsal horn, dorsolateral funiculus, intermediolateral cell columns and the area around the central canal. The distribution of VIP immunoreactivity was similar in all species studied, mouse, rat, guinea pig, cat, horse and the marmoset monkey. There were fewer VIP fibres in the dorsal horn of cervical and thoracic segments than in lumbosacral segments. Using radioimmunoassay this gradient increase was quantitatively most marked in the sacral spinal cord of the cat. In dorsal root ganglia few nerve cell bodies but numerous fibres were present. A dual origin for VIP in the spinal cord is suggested: (A) Extrinsic, from dorsal root afferent fibres since immunoreactivity was decreased in dorsally rhizotomized animals (cats and rats) and in capsaicin pretreated rats (microinjection of dorsal root ganglia). (B) From local cell bodies intrinsic to the spinal cord which became visible after colchicine pretreatment of rats.

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PubMedDate not supplied

The origin of VIP-containing nerves in the urinary bladder of rat.

The innervation of the urinary bladder is known to include a considerable number of nerves containing vasoactive intestinal polypeptide (VIP). The origin of such nerves in the bladder of rat was investigated in this study using the methods of immunocytochemistry and radioimmunoassay combined with surgical sectioning of the hypogastric and/or pelvic nerves to the bladder. Eight days after pelvic nerve sectioning proximal to the main pelvic ganglion, VIP-immunoreactive nerves and VIP content were markedly increased from the level in the sham-operated rat bladder. Sectioning of hypogastric or both nerve pathways led to a less significant increase. It was therefore postulated that the majority of VIP-immunoreactive nerves originate from ganglia located either close to the bladder or within the bladder wall. It is interesting that in these experiments the VIP content of the bladder nerves is inversely related to the changes in motility that would be expected to result from the nerve sections.

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PubMedDate not supplied

Calcitonin gene-related peptide (CGRP) in the female rat urogenital tract.

CGRP-immunoreactivity was found throughout the female rat urogenital tract by specific radioimmunoassay, and shown to be present in nerve fibres by immunocytochemistry. The highest concentrations of CGRP-like immunoreactivity were found in the urinary tract, with lower levels in regions of the genitalia. Chromatographic analysis of bladder and vaginal extracts on Sephadex G-50 columns and HPLC revealed at least three CGRP-immunoreactive peaks. The major peak emerged in the same position as synthetic rat CGRP. CGRP nerve fibres were associated mainly with blood vessels, non-vascular smooth muscle, squamous epithelium and uterine and cervical glands, and were particularly abundant in the ureter and bladder. CGRP-immunoreactivity was depleted by neonatal treatment with capsaicin and after surgical section of pelvic and/or hypogastric nerves. Immunocytochemistry demonstrated that depletion occurred predominantly in the mucosal layer of the urogenital tract. These findings indicate a sensory function for most of the CGRP-immunoreactive nerves in the rat urogenital tract.

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PubMedDate not supplied

Effect of 6-hydroxydopamine on neuropeptides in the rat female genitourinary tract.

The occurrence and distribution of neuropeptide Y has been determined in the rat female genitourinary tract by radioimmunoassay and chromatographic analysis. Within the bladder, higher concentrations of neuropeptide Y were found in the trigone (48.8 +/- 5.2 pmol/g) than in the dome (36.0 +/- 2.1 pmol/g). In the genital tract, highest concentrations were identified in the vagina (41.4 +/- 2.1 pmol/g). Treatment of rats with 6-hydroxydopamine resulted in significant depletion of neuropeptide Y concentrations in both parts of the bladder, together with vagina, uterine horn and fallopian tube. No change was observed in the cervix, uterine body and ovary. Concentrations of vasoactive intestinal polypeptide were unaffected by treatment with 6-hydroxydopamine except in the area of the cervix where concentrations rose from 64.1 +/- 5.7 pmol/g to 133.6 +/- 15.1 pmol/g (p less than 0.05). There was a generalised, but statistically insignificant rise in substance P concentrations.

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PubMedDate not supplied

Distribution of galanin immunoreactivity in the genitourinary tract of man and rat.

Galanin has been shown to be present in substantial quantities in the human and rat genitourinary tract by radioimmunoassay and immunocytochemistry. The highest concentrations measured by radioimmunoassay were found in the human vas deferens, corpus cavernosum and spongiosum and in the vagina and cervix. In man gel chromatographic analysis showed two molecular forms. The earlier eluting peak was different from porcine galanin standard. There was only one molecular form in the rat which emerged in an earlier position than the porcine standard. Galanin immunoreactive nerve fibres demonstrated in the genitourinary tract were found both in man and rat. They were found within smooth muscle and in close relationship to blood vessels. The presence and distribution of galanin in the genitourinary system suggest the possibility that this neuropeptide could play a role in the regulation of smooth muscle tone, blood flow and motility.

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PubMedDate not supplied

A VIP-containing system concentrated in the lumbosacral region of human spinal cord.

Neuropeptides were first localized in the human spinal cord by immunocytochemistry and substance P has been shown, by the same method, to be reduced ipsilaterally in the dorsal horn after limb amputation and bilaterally in the Riley-Day syndrome. Several neuropeptides increasingly fulfil the criteria to establish them as neurotransmitters or neuromodulators, and they may also have trophic actions in the spinal cord. Using radioimmunoassay and immunocytochemistry, we present here for the first time a quantitative regional distribution and localization of vasoactive intestinal polypeptide (VIP), substance P, somatostatin, bombesin and cholecystokinin (CCK-8) in normal postmortem human spinal cord. A comparison of the distribution of these peptides reveals an exceptional pattern for VIP, with relatively much higher levels in the lumbosacral region. Immunocytochemical analysis shows a distinctive distribution of VIP-containing fibres and terminals at the lumbosacral segments. This VIP-containing system may have an important role in the spinal control of urogenital function in man.

Bombesin↗
PubMedDate not supplied

The regional distribution of NPY-, PHM-, and VIP-containing nerves in the human female genital tract.

The regional distributions of neuropeptide Y (NPY), peptide histidine-methionine (PHM), and vasoactive intestinal polypeptide (VIP) immunoreactivities in the human female genital tract have been estimated by specific radioimmunoassays, and their molecular forms determined by chromatography. The localisation and distribution of these three peptides was carried out by immunocytochemistry. The vagina and cervix contain high concentrations of NPY- and VIP-immunoreactive nerves, mainly localised around the vascular and nonvascular smooth muscle. VIP-containing nerves were, in addition, seen beneath the cervical and, in particular, the vaginal epithelium. A comparatively high level of immunoreactive NPY is found in the fallopian tube, mainly around the circular muscle coat. There is evidence that VIP is a neurotransmitter in the female genital tract, and these results suggest a similar role for NPY and PHM.

Adult↗
PubMedDate not supplied

[Experimental data on the toxic action of hydrazine sulfate on the body and on a tumor].

Toxic action of hydrozine sulfate in rats and mice along with its influence on the mitotic activity of Walker carcino-sarcoma cells were studied. Single injections of the agent in high doses resulted in destruction of the animals during the first 2 days with no "delayed death" observed. Multiple injections caused a considerable loss of body weight. When given in toxic doses the agent did not influence hemopoiesis, but did affect sensitivity, drastically increasing the toxic action of ethanol or barbiturates. Administration of hydrazine sulfate in therapeutic doses decreased markedly the mitotic activity and increased the appearance of atypical mitotic cells.

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PubMedDate not supplied

X-irradiation chronosensitivity and circadian rhythmic proliferation in healthy and sarcoma-carrying rats' bone marrow.

Mitotic activity of bone marrow and tumor of sarcoma-bearing rats and of bone marrow of healthy controls is circadian periodic. Whereas the circadian rhythm in mitotic activity of bone marrow is similar for intact and tumor-bearing rats, with a peak occurring shortly after the onset of the dark (activity) span, the circadian rhythm in mitotic activity of tumor has a much smaller amplitude and a different acrophase occurring late in the dark span. This difference in acrophase of mitotic activity of bone marrow and tumor has important implications for scheduling the administration of oncotherapy. For the tumor model examined herein, it suggests the possibility to achieve concomitantly near maximal efficacy and near minimal myelotoxicity, a result awaiting further investigation in humans with different kinds of malignancies.

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