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The genetic basis of hyperinsulinism (excess blood levels of insulin), the most common cause of persistent hypoglycemia (low blood sugar) in infants, was explored in this study of 32 patients from 26 families. The patients represented all children seen at one hospital during a six-year period. Five of the families had more than one child affected (multiplex families), while the remaining 21 had one affected child only (simplex families). Multiplex and simplex patients were compared with respect to clinical and histological features. No significant differences in these variables were observed between the two types of patient. Calculations of the observed and expected number of affected children related to the sibship size yielded segregation ratios consistent with those expected for an autosomal recessive disorder. Evidence for two types of persistent hyperinsulinism, a familial and a sporadic type, does not seem to be present. Parents of affected children should be aware that the chances of having another affected child are one in four. (Consumer Summary produced by Reliance Medical Information, Inc.)

The effect of strict glycemic control on retinal volumetric blood flow rate (Q) was investigated in 13 insulin-dependent diabetic patients with laser Doppler velocimetry and monochromatic fundus photography. Strict glycemic [...]

Myoinositol is a sugar that is widely distributed in the human body and in various foods, including breast milk. It may be an important factor in human growth and is thought to play a role in the production of the surfactant, which protects the lungs of newborn babies suffering from respiratory distress syndrome. A study was conducted to determine: the normal blood levels of myoinositol in 65 mothers and infants at birth (both premature and full-term infants); the amount of this sugar in human milk, infant formula and parenteral (intravenous) feeding solutions; and levels of blood myoinositol in 15 premature infants receiving these three sources of nutrition. The results showed that at birth, the newborns had a higher blood level of myoinositol than their mothers. The myoinositol content of breast milk was significantly greater than the amount in parenteral solutions and infant formulas. During the three weeks that the group of 15 premature babies was studied, blood myoinositol increased in the breast-fed infants, but remained the same in the infants fed parenterally or with formula. It was concluded that newborns have higher blood myoinositol concentrations than adults and that their blood levels can be explained by the amount of the sugar supplied in their feedings. More research will be needed to assess whether myoinositol has a specific nutritional benefit and should be added to infant formulas. (Consumer Summary produced by Reliance Medical Information, Inc.)

An article in the November 1991 issue of the Journal of Pediatrics describes conservative (nonsurgical) management of infants with hyperinsulinism (elevated blood levels of insulin). Traditionally, such children are treated by removal of part of the pancreas (subtotal pancreatectomy), where the cells that manufacture insulin are located. The editorial takes issue with the article concerning its recommendation that surgery be postponed or not performed for patients with 'asymptomatic' hypoglycemia (very low blood sugar levels). Such patients may be in danger of brain damage even if symptoms are not apparent, and some of the glucose levels reported in the article appear dangerously low. The authors have focused too much on symptoms at the expense of absolute blood glucose levels. The effects of severe hypoglycemia may not be noticeable in infants because their repertoire of responses is limited. A broader issue of concern is the lack of knowledge concerning what constitutes a normal glucose level in newborn and very young babies. Normal levels are established by evaluating blood samples from nursery populations, but these are known to vary widely with feeding routines. Until firmer evidence regarding optimal levels is obtained, it would be wise to aim at a glucose concentration higher than 50 to 60 milligrams per deciliter, regardless of whether symptoms are present or absent. Surgery should be considered if this goal cannot be met. (Consumer Summary produced by Reliance Medical Information, Inc.)