PubMed Health⌕ Search

Biomedical subjects

S Charles

Publications and source records attributed to S Charles.

At least 19 recordsLinked to original sources
PubMed1991

[Platelet serotonin concentration in children under 5 years of age].

High platelet serotonin concentrations have been reported in children with early infantile autism. However, as yet there are no reference values regarding platelet serotonin in normal infants and young children so that it remains difficult to define the exact significance of this finding. We report here with the platelet serotonin concentration found in 57 infants and children (20 girls, 37 boys) ranging in age from 10 days to 5 years old. Our results show that mean platelet serotonin concentrations in infants and young children are significantly greater than mean values obtained in older children (+11%) and neonates in the umbilical cord (+64%). No significant variations were found relating to sex, leucocyte count and platelet count. There therefore appears to be a physiological elevation of platelet serotonin concentration in infants and young children, and this has to be taken into consideration in the interpretation of the elevated values found in cases of infantile autism.

Aging↗
PubMed1990

Ciliary sulcus suturing of a posterior chamber intraocular lens.

We describe a method for ciliary sulcus fixation of a posterior chamber intraocular lens (PC-IOL) in the absence of an intact posterior capsule. This method, which combines a lens fixation procedure with trans pars plana vitrectomy techniques to ensure safe manipulation of the lens implant in the absence of an intact anterior hyaloid face, is ideally suited for retrieval and repositioning of PC-IOLs dislocated into the vitreous. It also permits closed system repositioning and fixation of the implant, thereby avoiding the complications of vitreous loss and the need for reopening the limbal incision.

Adult↗
PubMed1988

Surgical decompression of branch retinal vein occlusions.

Many patients with branch retinal vein occlusions can develop significant long-term diminution of vision due to such complications as macular edema, retinal neovascularization, and vitreous hemorrhage. One of us (S.C.) developed a new surgical procedure that involves sectioning or decompression of the common sheath connecting the artery and vein at the crossing where a branch retinal vein occlusion occurs. The patient whose case we report had a visual acuity improvement from 20/200-2 to 20/25+1 eight months after surgery.

Female↗
PubMed1988

[Fatal cardiac complications in a child operated on for severe scoliosis with a Coffin-Lowry syndrome. Apropos of a case].

The Coffin-Lowry is characterized by mental retardation, characteristic facies and hands, and skeletal changes. Discovery of two others brothers presenting vertebral curvature and suffering from the same syndrome led to a familial investigation which allowed the making of an inventory of six members affected in this family. Only subjects with characteristic fingers were included because according to Lowry this anomaly is necessary to assert the Coffin-Lowry syndrome. The series is quite interesting because this is the greatest of Lowry with five cases. The authors emphasize the importance of a detailed preoperative cardiac exploration to search for cardiomyopathy the existence of which in Coffin-Lowry syndrome was never noted before.

Abnormalities, Multiple↗
PubMed1987

Measurement of anti-DNA antibodies: a reappraisal using five different methods.

One hundred and thirty coded sera, 60 from patients with systemic lupus erythematosus (SLE) and 70 from patients with other autoimmune rheumatic diseases were tested for deoxyribonucleic acid (DNA) binding activity by five different types of assay. These were enzyme linked immunosorbent assay (ELISA) (distinguishing IgG and IgM anti-ssDNA and anti-dsDNA), Crithidia luciliae, a nitrocellulose filter assay, the Amersham kit, and another modified Farr assay, the radioimmunoassay (RIA) (UK). The Crithidia test was the most specific, none of the controls was positive, but the least sensitive (13% positive only). The RIA (UK) was the most sensitive (57% positive). In most of the assays 3-9% of the controls were positive. When the SLE sera were analysed according to disease activity the IgG anti-dsDNA ELISA, all three RIA values, and the Crithidia test values were raised in all the patients with severely active disease. Some patients with inactive disease, however, were positive in each of the tests. The best interassay correlations (r less than 0.49) were found between RIA (UK), and ss IgG and the Amersham kit; and between ds IgG and ss IgG. In the main, however, it was clear that different assays are dependent upon distinctive properties of DNA antibodies. It seems inevitable that most major rheumatology units will require more than one anti-DNA antibody assay.

Adolescent↗
PubMed1983

Distinct effects of various amino acids on 45Ca2+ fluxes in rat pancreatic islets.

The effects of three types of amino acids on 45Ca2+ fluxes in rat pancreatic islets have been compared. Alanine, a non-insulinotropic neutral amino acid, transported with Na+, increased 45Ca2+ efflux in the presence or in the absence of extracellular Ca2+, but not in the absence of Na+. Its effects in Na+-solutions were practically abolished by 7 mM-glucose. Alanine slightly stimulated 45Ca2+ influx (5 min uptake) only when Na+ was present. Two insulinotropic cationic amino acids (arginine and lysine) triggered similar changes in 45Ca2+ efflux. They accelerated the efflux in the presence of Ca2+ and inhibited the efflux in a Ca2+-free medium, whether glucose was present or not. In an Na+-free Ca2+-medium, arginine and lysine markedly accelerated 45Ca2+ efflux, but this effect was suppressed by 7 mM-glucose. Arginine stimulated 45Ca2+ influx irrespective of the presence or absence of glucose and Na+. Leucine, a neutral insulinotropic amino acid well metabolized by islet cells, inhibited 45Ca2+ efflux from the islets in a Ca2+-free medium; this effect was potentiated by glutamine. In the presence of Ca2+ and Na+, leucine was ineffective alone, but triggered a marked increase in 45Ca2+ efflux when combined with glutamine. In an Na+-free Ca2+-medium, leucine accelerated 45Ca2+ efflux to the same extent with or without glutamine. Leucine also stimulated 45Ca2+ influx in the presence or in the absence of Na+, but its effects were potentiated by glutamine only in the presence of Na+. The results show that amino acids of various types cause distinct changes in 45Ca2+ fluxes in pancreatic islets. Certain of these changes involve an Na+-mediated mobilization of cellular Ca2+ from sequestering sites where glucose appears to exert an opposite effect.

Alanine↗
PubMed1983

Ocular hypothermia: anterior chamber perfusion.

The anterior chambers of 27 rabbit eyes were perfused at constant pressure with room temperature (25 degrees C) or cooled (11 degrees C) balanced salt solution at constant flow rates of 4.8 ml/min or 8.5 ml/min. Intraocular temperature changes in the anterior chamber, anterior vitreous, mid vitreous, and posterior vitreous and on the retina surface were monitored with an intraocular thermocouple probe. Perfusion of the anterior chamber of the pigmented rabbit eye with cooled fluid significantly reduced the temperature of the anterior chamber and anterior vitreous and even that of the retina. Both an increase in the rate of perfusion and a lowering of the perfusion temperature enhanced the cooling effect. The observed decrease in temperatures returned to approximately normal 4 minutes following the cessation of perfusion.

Animals↗
PubMed1982

A single mechanism for the stimulation of insulin release and 86Rb+ efflux from rat islets by cationic amino acids.

The mechanisms by which cationic amino acids influence pancreatic B-cell function have been studied by monitoring simultaneously (86)Rb(+) efflux and insulin release from perifused rat islets. The effects of two reference amino acids arginine and lysine were compared with those of closely related substances to define the structural requirements for recognition of these molecules as secretagogues. Arginine accelerated (86)Rb(+) efflux and increased insulin release in the absence or in the presence of 7mm-glucose. Its effects on efflux did not require the presence of extracellular Ca(2+) or Na(+), but its insulinotropic effects were suppressed in a Ca(2+)-free medium and inhibited in an Na(+)-free medium. Among arginine derivatives, only 2-amino-3-guanidinopropionic acid mimicked its effects on (86)Rb(+) efflux and insulin release; citrulline, guanidinoacetic acid, 3-guanidinopropionic acid and guanidine were inactive. Norvaline and valine also increased (86)Rb(+) efflux, but their effect required the presence of extracellular Na(+); they did not stimulate insulin release. Lysine as well as the shorter-chain cationic amino acids ornithine and 2,4-diaminobutyric acid accelerated (86)Rb(+) efflux in a Ca(2+)- and Na(+)-independent manner. Their stimulation of insulin release was suppressed by Ca(2+) omission, but only partially inhibited in an Na(+)-free medium. The uncharged glutamine and norleucine increased the rate of (86)Rb(+) efflux in the presence of glucose, only if extracellular Na(+) was present. Norleucine slightly increased release in a Ca(2+)- and Na(+)-dependent manner. The effects of lysine on efflux and release were not mimicked by other related substances such as 1,5-diaminopentane and 6-aminohexanoic acid. The results suggest that the depolarizing effect of cationic amino acids is due to accumulation of these positively charged molecules in B-cells. This causes acceleration of the efflux of K(+) ((86)Rb(+)) and activation of the influx of Ca(2+) (which triggers insulin release). The prerequisite for the stimulation of B-cells by this mechanism appears to be the presence of a positive charge on the side chain of the amino acid, rather than a specific group.

Amino Acids↗