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Biomedical subjects

C Collin

Publications and source records attributed to C Collin.

86 records · Page 5Linked to original sources
PubMed1985

Hemispheric contribution to vertex augmentation/reduction of the auditory evoked potential.

Starting off from the notion that the cerebral hemispheres differ in their processing mode, this paper reports on stimulus intensity modulation of auditory evoked potentials recorded from hemispheric leads (C3 and C4 referenced to ipsilateral mastoid processes) in a sample of 40 male Ss between 18 to 40 years of age. The experimental set up involved the recording of series of 100 trials to binaural clicks of 63.5, 74.6 and 85 dB AL. Ss who were augmenters at the vertex showed positive Amplitude-Intensity function slopes over the left hemisphere; when Ss were Reducers at the vertex, the slopes were negative on the right hemisphere. These results are interpreted in terms of attention deployment or allocation to one or the other hemispheric processing mode. This might constitute a trait-like enduring subject characteristic whose relation to traditional psychometric variables needs further exploration. The modality specificity of this phenomenon is also discussed.

Acoustic Stimulation↗
PubMed1985

Do non-spermatozoal cells mainly stem from spermiogenesis? Study of 106 fertile and 102 subfertile men.

The various non-spermatozoal cell types in the semen of 106 fertile (F) and 102 subfertile (SF) men were described and their relative proportions estimated. About 94% (F) and 90% (SF) were found to be germinal elements, among which, respectively, about 27% and 51% were spermatids, 48% and 36% residual bodies, 19.4% and 2.6% primary spermatocytes, 0.03% and 0.61% spermatogonia. The epithelial cells and blood cells represented about 6% (F) and 10% (SF) of the non-spermatozoal cells; in F men 5.3% and in SF men 9.5% were found to be polymorphonuclear leucocytes. In SF men the predominance of spermatids might be due to a particular fragility of spermiogenesis. To the three stages of spermatogenesis-the gonial multiplication, meiosis, and spermiogenesis-might correspond three specific pathologies. A pathology of the very germ cell production was thus suggested, as well as a pathology of the means by which the final product would be controlled. The Sertoli cell was supposed to be mainly involved in the latter process.

Cell Count↗
PubMed1981

[Monocular enucleation causes a deficit in visual learning in rats].

Behavioral effects of monocularity were assessed in rats, by means of visual discrimination training in a jumping box. The results showed that the experimental subjects did not differ from controls in brightness discrimination, however, were significantly inferior on a conditional discrimination task. This particular test involves the association of present cues with previously learned ones. Since previous work proposes the consideration of the rat's brain as a functional split-brain, and in our condition the visual information was highly lateralized only to the contralateral hemisphere, we suggest that our results may be due to an impairment produced by the reduction of the brain mass available for the discrimination.

Animals↗
PubMed1980

On the measurement of alexithymic behavior.

It is suggested in this paper that alexithymia may be a graded behavioral characteristic in much the same way as psychological dimensions are. Under this assumption every person would possess an alexithymic score, however low it could be, and the basis for distinguishing between diagnostic groups would thence be quantitative rather than qualitative. The measurement of alexithymia in any given individual poses two main problems: the nature of the underlying phenomenon and the instruments that should be used for its depiction. Whether alexithymia is a trait, a state, or both cannot be answered confidently at present. On the other hand, its quantitative assessment depends upon an interaction between phenomenon, observer and situation. Some data bearing on the application of the Beth Israel Alexithymic and Psychosomatic Questionnaire by informed and uninformed interviewers suggest the need for reliability studies of this instrument. Also advanced is the possibility that some aspects of the syndrome (reflected differently in the questionnaire items) might be easier to detect or more amenable to quantitative assessment, thus suggesting that some weighting of items is needed in order to obtain a total alexithymia score.

Adult↗
PubMed1975

Infusion thrombophlebitis and infection with various cannulas.

A prospective study was carried out of the frequency of thrombophlebitis and bacterial contamination of cannulas associated with four commonly used intravenous cannulas of differing length and chemical composition. For all cannulas the frequency of thrombophlebitis increased significantly with time. Long 'Teflon' cannulas were significantly more likely to be contaminated with bacteria and associated with thrombophlebitis than all other cannulas, while the low frequency of thrombophlebitis with butterfly stainless steel cannulas was shown to be due to their short duration of use. It is suggested that long teflon cannulas should be avoided and that infusion thrombophlebitis could be eliminated as a clinical problem by the use of intermittent short duration intravenous infusions.

Bacteriological Techniques↗
PubMed1974

Letter: Cot deaths.

Explore the source record for details and available documents.

Body Temperature↗
PubMedDate not supplied

Expression of peroxisome proliferator activated receptors (PPARs) in human hair follicles and PPAR alpha involvement in hair growth.

Peroxisome proliferator-activated receptors (PPARs), which belong to the nuclear hormone receptor superfamily, have recently been described as potent key regulators of epidermal development. As 1,25-dihydroxyvitamin D3, retinoic acid and triiodothyronine are known to exert effects on skin and hair follicle growth through similar receptors, we decided to investigate both the expression pattern of the PPAR alpha, -delta and -gamma subtypes and their role in human hair follicles. Using reverse transcriptase-polymerase chain reaction and immunohistochemistry, we established that PPAR alpha, -delta and -gamma were expressed in both dermal and epithelial human hair follicle cells. Additionally, we evaluated the dose effect of clofibrate, a PPAR alpha ligand, on the survival of human hair follicles in culture. A beneficial effect was observed within a narrow range of concentrations.

Cell Survival↗