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Biomedical subjects

J Perrin

Publications and source records attributed to J Perrin.

At least 19 recordsLinked to original sources
PubMed1992

Antimutagenic effects of radioprotector WR-2721 against fission-spectrum neurons and 60Co gamma-rays in mice.

The antimutagenic effects of the radiation protective agent, S-2-(3-aminopropylamino)ethylphosphorothioic acid (WR-2721), were studied against fission-spectrum-neutron- and 60Co-gamma-ray-induced mutagenesis in mice. Mutagenesis at the hypoxanthine-guanine phosphoribosyl transferase (hprt) locus was measured 56 days following whole-body irradiation with JANUS neutrons (single doses, 50-150 cGy) or 60Co photons (single doses, 250-750 cGy). Splenic T lymphocytes from B6CF1 mice were grown in round-bottomed 96-microwell culture plates with or without the selective agent 6-thioguanine (6-TG). The mutant frequency, as a result of exposure to neutrons or 60Co photons, increased 100-fold with dose. Doses of 150 cGy neutrons and 750 cGy 60Co photons were equally mutagenic. When animals were injected with WR-2721 at a dose of 400 mg/kg body weight, i.p., 30 min before whole-body irradiation with JANUS neutrons or 60Co photons, mutant frequencies were significantly reduced at all radiation doses (i.e. protection factors of 1.4 and 2.4, respectively). Thus, the aminothiols are effective antimutagens. A novel clinical application of these compounds could be in their use to protect against radiation- and/or chemotherapy-induced genotoxic damage to normal cells.

Amifostine↗
PubMed1992

The radioprotector WR-2721 reduces neutron-induced mutations at the hypoxanthine-guanine phosphoribosyl transferase locus in mouse splenocytes when administered prior to or following irradiation.

An in vitro T-lymphocyte cloning technique has been applied to study the effects of JANUS fission-spectrum neutron irradiation and the radioprotector S-2-(3-aminopropylamino) ethylphosphorothioic acid (WR-2721) on the subsequent development of somatic mutations at the hypoxanthine-guanine phosphoribosyl transferase (hprt) locus in hybrid B6CF1 male mice. In control studies performed to establish an in vitro cloning technique, the mutant frequencies of splenic T-lymphocytes, as a result of exposure to a 100 cGy dose of neutrons, increased with time from a control level of 9 x 10(-7) to a maximum value of 1.7 x 10(-5) at 56 days following irradiation. Between 56 and 150 days after irradiation, mutant frequencies were observed to plateau and remain stable. All subsequent determinations were performed at 56 days following the experimental treatment of animals. WR-2721 at a dose of 400 mg/kg was effective in protecting against the induction of hprt mutants (i.e. a mutant frequency reduction factor, MFRF) following the largest dose of neutrons used (i.e. 150 cGy), whether it was administered i.p. 30 min before, 5 min after, 3 h after, or three times at 3, 24, and 48 h after, as evidenced by MFRFs of 6.0, 6.6, 4.8 and 5.8 respectively. The antimutagenic effectiveness of WR-2721 administered 30 min prior to irradiation was unaffected, even when the dose was reduced to 200 mg/kg, MFRF = 7.0; 100 mg/kg, MFRF = 3.8; and 50 mg/kg, MFRF = 8.9. These findings confirm our earlier report using the radioprotector N-(2-mercaptoethyl)-1,3-diaminopropane (WR-1065) under in vitro conditions, and demonstrate that these agents can be used as effective antimutagens even when they are administered up to 3 h following radiation exposure.

Amifostine↗
PubMed1992

Influence of the transport on the outcome of the bacteriological analysis of dog urine comparison of three transport tubes.

A sterile plastic tube, a boric acid-glycerol-sodium formate tube and a dip-slide tube were compared for transport of dog urine for bacteriological examination under practice conditions, at ambient temperature. In a first part, 50 dog urine samples were cultured on agar plates and on a dip-slide kit within 2 h after collection and after storage at 20 degrees C in a sterile tube and in a boric acid tube for 24 h and 48 h. Culture of the samples stored in the boric acid tube and culture on the dip-slide yielded results which correlated very well with those of the culture of fresh urine. However, culture of the samples stored in the sterile tube yielded up to 65% false positive results. In a second part, a comparison was drawn with culture results of 100 dog urine specimens collected by different practitioners and simultaneously mailed to our laboratory in a sterile tube, in a boric acid tube and in a dip-slide kit. Samples sent in the boric acid and in the dip-slide tube showed comparable culture results. Culture of the samples sent in the plastic tube yielded 53% false positive results in comparison with those of the samples preserved in boric acid.

Animals↗
PubMed1991

Sensitivity of lateral hypothalamic neurons to glycemic level: possible involvement of an indirect adrenergic mechanism.

Most of the lateral hypothalamic neurons responding to moderate changes in blood glucose fail to be affected by direct glucose applications. Therefore their sensitivity to glycemic level must be mediated by an indirect mechanism. In order to test whether adrenergic afferents might be involved, the activity of lateral hypothalamic neurons was recorded during hyperglycemia and local glucose and epinephrine microiontophoresis. A majority of the recorded cells sensitive to local epinephrine responded to this substance with a decrease in activity. While no consistent correspondence was found between the responses of the same cells to local glucose and epinephrine ejections, almost all the neurons sensitive to glycemic alterations responded in the same direction to hyperglycemia and iontophorised epinephrine. These results support the view that the activity of lateral hypothalamic cells can be modulated in relation to changes in glycemic level through adrenergic signals released by some neurons which are sensitive to the blood glucose. The possible localization in the solitary tract area of such neurons projecting to the lateral hypothalamus is discussed.

Animals↗
PubMed1979

[Effect of stimulation of splanchnic mechanoreceptors on the activity of purkinje cells (author's transl)].

Climbing and mossy fibre activity in Purkinje cells of cat cerebellum (vermis part of lobules V and VI) were recorded by means of extracellular microelectrodes. Responses were obtained by stimulation of different types of mechanoreceptors in the gastro-intestinal tract: muscular receptors connected with C fibres, peritoneal movement receptors connected with A gamma delta or B fibres, Pacinian corpuscules connected with A beta fivres. The characteristics of the splanchnic fibre projections on this cerebellar area were defined. Splanchno-somatic, splanchno-visceral, and splanchno-cortical convergences were demonstrated.

Animals↗
PubMed1979

Significance of immunoglobulin deposition in peripheral nerve in neuropathies associated with paraproteinaemia.

Direct and indirect immunofluorescent studies of sural nerves were carried out in two patients with paraproteinaemia and neuropathy, in four other patients with axonal or demyelinating neuropathies, and in one normal sural nerve. IgM was demonstrated directly in the two cases of paraproteinaemia and neuropathy, and indirectly, using the serum of one of these cases, in a case of axonal neuropathy and in one case of chronic Guillain-Barré syndrome. In the latter case, IgM deposition also occurred after exposure to normal serum. These results suggest that the paraprotein itself did not directly cause neuropathy, but that immunoglobulin deposition is probably a secondary process, caused by diffusion into damaged nerves.

Aged↗
PubMed1979

[Recording and data processing of electrical signals of the specific atrioventricular conduction pathways in man].

Signals of the electrical activity of the specific atrioventricular conduction pathways were recorded with an unipolar lead to obtain an exact time reference. The amplifier used had special characteristics: high gain settings (up to 300,000), very low noise levels, and wide filter range (2 Hz - 1,600 Hz). The low amplitude of the signals under study, of the order of a microvolt, and the wide filter range of the amplifier necessitated placing the patient in a Faraday cage. The signals recorded on magnetic tape were treated by a system of analysis for signal treatment. The method of averaging was used to extract the signal from background noise especially that arising from somatic muscle. The amplitude of the Hisian signal was much larger than that usually obtained with other methods. The intervals were determined with precision of the order of 1 millisecond. Frequential analysis of the signals gave another representation of the information contained in the time signals. This new representation seems to give better discrimination of the different zones of activation of the specific atrioventricular conduction pathways.

Adult↗
PubMed1979

[Stabilisation of total hip arthroplasty. Hemodynamic and gasometric disturbances (author's transl)].

This work aims at studying the operative complications of the stabilisation of total hip arthroplasties with the help of 11 hemodynamic studies, 19 functional records of the epinephrines and 25 surveys of the impact of the stabilisation on arterial blood gas. 1) Within the few minutes following the implantation of bone cement one may remark: -- a drop in the average arterial pressure, -- greater lowering of the stroke index after a femoral implantation than after a cotyloïdal implantation, -- a constant and massive rise of pulmonary resistances which appears mainly after a femoral stabilisation. 2) The hemodynamic disturbances are accompanied by neither a significant rise nor a significant fall of the plasmatic and urinary levels of the epinephrines. 3) There appears with the insertion a massive hypoxemia which can be prevented by the inhalation of pure oxygen.

Aged↗
PubMed1978

Solitary maxillary central incisor and normal stature.

Two children, one boy and one girl, each with solitary maxillary deciduous and permanent central incisors, normal height, and normal plasma growth hormone levels, are reported. Review of the literature reveals fourteen reports of patients with a similar dental anomaly. Of these, three are normal in height. The height and growth rate of patients with a single maxillary central incisor should be evaluated prior to growth hormone evaluation; such investigation should be undertaken only if the height is two standard deviations below the mean or if there is evidence of plateauing of linear growth.

Abnormalities, Multiple↗
PubMed1977

Immunofluorescent localisation of enterokinase in human small intestine.

The distribution of enterokinase in human intestine was studied in operative mucosal biopsies using specific antiserum to human enterokinase, previously purified to apparent homogeneity by affinity chromatography and immunoabsorption. Fluorescence was observed in the brush-border and glycocalyx of the duodenum and proximal 15 cm of jejunum distal to the D/J flexure. Distal jejunum and ileum as well as stomach and colon were consistently negative. Brunner's glands and goblet cells were never stained by specific antibody. Preliminary evidence was obtained that the human enterokinase molecule contains a specific antigenic determinant in its polypeptide component and a second determinant in the oligosaccharide moiety which cross-reacts with blood group A. Preliminary evidence was also obtained that mucosal synthesis of enterokinase may be impaired in jaundice due to carcinoma of the pancreas and induced in the small intestine distal to the normal limit of synthesis after pancreatico-duodenectomy.

Duodenum↗