Stability and reproducibility of the biologic activity of premixed short-acting and intermediate-acting insulins.

Mixtures of short-acting and intermediate-acting insulins often represent an effective regimen to achieve near-normal blood glucose values, yet controversy exists concerning the stability and predictability of such mixtures. In a study of diabetic patients, the biologic activity of a specific intermediate-acting insulin (insulatard) and a short-acting insulin (Velosulin) premixed in a 70:30 ratio was reproducible at three intervals and was stable for a period of up to three months. The serum levels of free insulin and the rate of onset and extent of the blood glucose lowering effects were not altered, showed two distinct peaks, and were comparable to those experienced with separate injections of equivalent doses of the intermediate-acting and short-acting insulins.

Regulation of plasma arginine vasopressin in patients with chronic renal failure maintained on hemodialysis.

Plasma arginine vasopressin (PAVP) was studied in patients before and after hemodialysis. The levels of PAVP were higher before and reverted to normal range after dialysis (5.7 vs. 2.7 pg/ml). Sequential chemical dialysis showed that vasopressin was removed during the chemical dialysis phase. Data obtained during a simulation experiment were also consistent with the view that vasopressin was removed during the chemical dialysis phase.

Hypothalamic sarcoidosis and hypopituitarism.

4 patients with presumed pituitary hypothalamic sarcoidosis are described. 3 had histological diagnoses compatible with sarcoidosis and in the other this diagnosis was strongly suspected from chest X-rays. 2 patients presented with diabetes insipidus. ACTH reserve was diminished in 3 out of 4 and growth hormone reserve was diminished in the 3 who were tested. All 4 patients developed secondary amenorrhea. 3 patients had hypothalamic hypothyroidism. Prolactin dynamics were intact. Tomograms of the sella turcica in all 4 and computerized tomography of the hypothalamic area in 2 patients failed to reveal any abnormality.

NSILA and foetal growth.

Employing a sensitive competitive protein binding assay for NSILA (non-suppressible insulin-like activity), circulating levels of this somatomedin (SM) have been measured throughout pregnancy, at parturition, and in foetal and newborn sera. Acid-dissociable serum NSILA (mean +/- SEM) in 57 women was significantly higher during pregnancy (1106 +/- 46 microunits/ml), than in 11 adult non-pregnant control subjects (844 +/- 22 microunits/ml), but not correlated with week of gestation or with serum growth hormone (GH) or cortisol levels. At parturition, the NSILA concentration in 28 cord sera (598 +/- 38 microunits/ml) was significantly less than in the corresponding maternal sera (1039 +/- 63 microunits/ml). The NSILA levels in 23 premature newborns (370 +/- 20 microunits/ml) and 8 small-for-gestational-age newborns (310 +/- 46 microunits/ml) were significantly less than in 33 term newborns (494 +/- 18 microunits/ml). Serum NSILA in 56 term and premature newborns exhibited a significant positive correlation both with gestational age and birth weight but not with serum GH or cortisol levels. These data suggest that the maternal-foetal growth-promoting system is a highly complex one in which NSILA levels both in maternal and foetal circulations appear to be under multifactorial control.

Hydrocephalus and amenorrhea.

A 25-year-old woman was seen for the complaint of secondary amenorrhea. Skull roentgenograms revealed a markedly enlarged sella turcica. Studies of pituitary and hypothalamic function including prolactin were normal. A pneumoencephalogram revealed dilated ventricles and a mass in the septum pellucidum and hypothalamus. Partial removal of this hypothalamic astrocytoma and placement of an interventricular shunt resulted in the return of menses. Recurrent obstruction a few months later resulted in headache, disorientation, and amenorrhea. A shunt was placed again, resulting in clearing of symptoms and a reestablishment of normal menstrual cyclicity. It appears that the occurrence of increased intracranial pressure rather than the hypothalamic tumor caused the amenorrhea.

Primary hypothyroidism and pituitary enlargement. Radiological evidence of pituitary regression.

A patient with primary hypothyroidism and pituitary gland enlargement was studies extensively before and after replacement therapy with levothyroxine sodium. She had evidence of bulging of the diaphragma sellae and increased serum prolactin levels. Thyroid replacement therapy resulted in regression of the pituitary size, as shown on pneumoencephalogram, but mildly elevated serum prolactin levels persisted.