Insulin binding to erythrocytes of nonpregnant women: a reevaluation, underlining the importance of body weights even in nonobese subjects.

Insulin binding to erythrocytes was measured in 18 healthy, non-obese women in the follicular phase and in 6 women in the mid-luteal phase of the same menstrual cycle. The presence of 55 nM and 220 nM monoclonal anti-IGF I receptor antibody (alpha-IR3) reduced only the number of low affinity binding sites for insulin by 20% and 33%, respectively. Women with relative body weights 110-119% had a lower number of high affinity receptors and an increased high affinity compared to women with relative body weights 91-109%. In women with relative body weights greater than or equal to 100%, maximum specific binding and high affinity constants increased and the receptor numbers decreased from the follicular to the luteal phase, whereas in women with relative body weights less than 100% the parameter changes were reverted. The data indicate: (1) erythrocytes contain two different classes of binding sites for insulin, (2) IGF I receptors might contribute to low-affinity binding of insulin to erythrocytes and (3) the relative body weight must be considered even for 'non-obese' control groups used in insulin binding studies of various clinical conditions.

Serum fructosamine and amniotic fluid insulin levels in patients with gestational diabetes and healthy control subjects.

Gestational diabetic pregnancies with fetal hyperinsulinism should be identified because these cases require insulin therapy. To determine the relationship between the serum fructosamine and amniotic fluid insulin concentrations, these substances were measured in 87 pregnant women with impaired glucose tolerance. Fructosamine was also measured in 678 healthy pregnant control subjects, in 113 of whom amniotic fluid insulin levels were available. Fetal hyperinsulinism was rare at serum fructosamine levels of less than 2.6 mmol/L. These results suggest that when both the oral glucose tolerance test and fructosamine level are used, only 30% of women with gestational diabetes need to undergo amniocentesis to assess fetal insulin homeostasis.

[Are there pre- or perinatal risk factors for sudden infant death?]. / Gibt es prä-oder perintale Risikofaktoren für den plötzlichen Säuglingstod?

The question was posed, whether a relationship could be established between prenatal and perinatal events and subsequent sudden infant death. The birth records of eighty mothers, whose infants died of sudden infant death syndrome (SIDS) between 1982 and 1987, were reviewed for obstetric complications. The records immediately following the respective SIDS cases served as controls. A family history of SIDS was found significantly more often in the SIDS group than in the control group (p less than 0.001). Oxytocin was administered significantly more often in the SIDS group than in the control group: 54/80 (= 68%) and 20/80 (= 25%, p less than 0.001), respectively. Smoking, hypotension requiring treatment and the administration of tocolytic agents were found significantly more frequently in the SIDS group than in the control group (p less than 0.01, p less than 0.001, and p less than 0.05). Transient fetal hypoxia, as a result of reduced flow in the uterine artery, seems possibly to be connected to the vasoactive agent Oxytocin when occurring in the three above named groups. Whether these situations are connected to a later development of SIDS, has not, to date, been confirmed.