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M Genel

Publications and source records attributed to M Genel.

107 records · Page 6Linked to original sources
PubMed1969

Intestinal beta-galactosidases. II. Biochemical alteration in human lactase deficiency.

Despite the high prevalence of intestinal lactase deficiency in some racial groups and in patients with intestinal disease, the biochemical defect has not been characterized. In the preceding paper normal intestine was found to have two lactases with distinctly different pH optima. Therefore, pH activity curves of homogenates from lactase-deficient intestine were studied, and the pH optimum was found to be shifted from the normal of 5.8 to 4.8. Density gradient ultracentrifugation of intestinal material from five lactase-deficient patients demonstrated absence of a lactase with pH optimum 6.0 and molecular weight 280,000. A second lactase with pH optimum 4.5 and molecular weights of 156,000 and 660,000 remained at normal levels accounting for the shift in the pH optimum in whole intestinal homogenates. In addition, three of the five patients had absence of a smaller beta-galactosidase (molecular weight 80,000) that had specificity only for synthetic substrates. Although not a lactase, this enzyme had a pH optimum identical with the missing lactase, and its activity was inhibited by lactose in a partially competitive manner suggesting that it is capable of binding lactose. It is possible that this enzyme is a precursor or fragment of the missing lactase.The residual lactase activity provided by the lactase with low pH optimum represents 20-70% of the activity of the missing enzyme, and yet these patients are not able to digest dietary lactose. Thus it appears that the residual enzyme plays no significant role in the hydrolysis of ingested lactose.

Adult↗
PubMedDate not supplied

Gender verification of female athletes.

The International Olympic Committee (IOC) officially mandated gender verification for female athletes beginning in 1968 and continuing through 1998. The rationale was to prevent masquerading males and women with "unfair, male-like" physical advantage from competing in female-only events. Visual observation and gynecological examination had been tried on a trial basis for two years at some competitions leading up to the 1968 Olympic Games, but these invasive and demeaning processes were jettisoned in favor of laboratory-based genetic tests. Sex chromatin and more recently DNA analyses for Y-specific male material were then required of all female athletes immediately preceding IOC-sanctioned sporting events, and many other international and national competitions following the IOC model. On-site gender verification has since been found to be highly discriminatory, and the cause of emotional trauma and social stigmatization for many females with problems of intersex who have been screened out from competition. Despite compelling evidence for the lack of scientific merit for chromosome-based screening for gender, as well as its functional and ethical inconsistencies, the IOC persisted in its policy for 30 years. The coauthors of this manuscript have worked with some success to rescind this policy through educating athletes and sports governors regarding the psychological and physical nature of sexual differentiation, and the inequities of genetic sex testing. In 1990, the International Amateur Athletics Federation (IAAF) called for abandonment of required genetic screening of women athletes, and by 1992 had adopted a fairer, medically justifiable model for preventing only male "impostors" in international track and field. At the recent recommendation of the IOC Athletes Commission, the Executive Board of the IOC has finally recognized the medical and functional inconsistencies and undue costs of chromosome-based methods. In 1999, the IOC ratified the abandonment of on-site genetic screening of females at the next Olympic Games in Australia. This article reviews the history and rationales for fairness in female-only sports that have led to the rise and fall of on-site, chromosome-based gender verification at international sporting events.

Chromatin↗
PubMedDate not supplied

Optimal insulin delivery in adolescents with diabetes: impact of intensive treatment on psychosocial adjustment.

The psychosocial effects of recent advances in the management of diabetes mellitus are unknown and could conceivably be adverse, particularly during the critical period of adolescence. Seven teenagers were evaluated by standard psychosocial scales and a detailed questionnaire before and on completion of a 6-mo intensive management program utilizing home glucose monitoring and multiple injections or the insulin infusion pump. All achieved improved metabolic control with inpatient glucose values (during 24-h monitoring) falling from 244 +/- 58 to 108 +/- 10 mg/dl, glycosylated hemoglobin levels falling from 11.8 +/- 2.9% to 8.4 +/- 1.7%, and home glucose levels averaging 121 +/- 16 mg/dl. Standardized scales evaluating depression, diabetic adjustment, self-esteem, and social adjustment indicated no deterioration in psychosocial functioning. There was a statistically significant increase in locus of control scores, suggesting an improved sense of internal control of life events. The program questionnaire revealed a positive response to both the program and the control devices used. This study suggests that the positive metabolic benefits of intensive diabetic management during adolescence are not offset by adverse psychosocial effects and indeed positive psychosocial benefits may result.

Adaptation, Psychological↗
PubMedDate not supplied

Intellectual development in children whose mothers received propylthiouracil during pregnancy.

Standard intelligence tests were administered to twenty-eight children who had been exposed to PTU in utero and thirty-two non-exposed siblings. There was no significant difference in results between the two groups. The present study suggests that with careful attention, pregnant women with thyrotoxicosis can be treated with propylthiouracil without interfering with subsequent intellectual development in the offspring.

Adolescent↗
PubMedDate not supplied

Long-term improvement of metabolic control with the insulin pump does not reverse diabetic microangiopathy.

Restoration of near-normal glucose metabolism with the insulin pump reduces retinal fluorescein leakage and microalbuminuria in diabetes. However, it is not known whether these functional changes reflect a true reversal of diabetic retinopathy or nephropathy. To evaluate this question, we studied the effect of 1-2 yr of insulin pump treatment on clinical endpoints in 17 type I diabetic patients. In each patient, plasma glucose and total glycosylated hemoglobin levels fell to normal or near-normal levels. The total daily dose of insulin given during the first month of pump treatment (52 +/- 5 U/day) was comparable to that given during conventional treatment (44 +/- 3 U/day) and varied little over the 1-2 yr period of observation. Ten eyes without retinopathy at the start of the study remained without retinopathy after 15-23 mo of pump treatment. One of eleven eyes with background retinopathy developed proliferative retinopathy and 3 of 13 eyes with proliferative retinopathy progressed during pump treatment. Similarly, no improvement in renal function was observed in the six patients with diabetic nephropathy on entry to the study. In the first month of pump treatment, proteinuria consistently fell to values 30% below prepump levels (P less than 0.005). However, the diminution in proteinuria was not sustained and all remain proteinuric after 13-18 mo of pump therapy. Serum creatinine rose slightly and creatinine clearance did not significantly change. These data suggest that insulin pump treatment does not reverse established diabetic microvascular complications, despite a sustained improvement in metabolic control for up to 2 yr.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗