[Microalbuminuria and macrovascular risk factors in insulin-dependent diabetic children]. / Microalbuminuria y factores de riesgo macrovascular en niños diabéticos insulino-dependientes.

OBJECTIVE: To investigate the prevalence of microalbuminuria in children and teenagers with IDDM and its relationship with other variables. METHODS: We studied 160 IDDM children and teenagers with a mean age of 13 +/- 4 years from our endocrine department outpatient clinic. A complete medical history was obtained as well as a fasting blood sample for glycemia, glycosilated hemoglobin and lipid profile and a urine sample for microalbuminuria using laser immunonephelometry. RESULTS: 13 patients (8%) had microalbuminuria (20-200 micrograms/min) and 5 (3%) clinical proteinuria (> 200 micrograms/min). The abnormal excretion was more prevalent in females with the poorest metabolic control, the longest duration of diabetes, and the highest age (13-18 years). The presence of microalbuminuria or clinical proteinuria associated with a more atherogenic risk profile compared to patients with a normal urinary albumin excretion. CONCLUSIONS: There was a poor metabolic control in our IDDM population. In addition, our current findings in a population with a relatively short duration of their diabetes point out the need to improve an integral management strategy to prevent or delay the late complications associated with IDDM.

Pentoxifylline reduces proteinuria in insulin-dependent and non insulin-dependent diabetic patients.

Pentoxifylline is a drug with hemorheological actions used in the management of microcirculatory abnormalities, such as those usually seen in diabetic patients. The drug has been successfully used in improving peripheral and central circulation, as well as proteinuria of long-term diabetes. With the hypothesis that pentoxifylline reduces proteinuria in patients with IDDM and NIDDM, with a wide range of urinary protein excretion, 86 diabetic patients were studied. Forty-one patients with IDDM were stratified in 2 subgroups: one of 18 patients with microalbuminuria, and the other of 23 patients with overt proteinuria. In the same way, 45 patients with NIDDM were divided in 2 subgroups: one of 23 patients with microalbuminuria, and the other of 22 patients with proteinuria. Patients in each subgroup were randomized to receive either placebo or pentoxifylline 1,200 mg/d, during 4 months, using a double blind design. At the beginning of the study and after treatment, 24-hour urinary albumin excretion was measured by nephelometry in each patient.(ABSTRACT TRUNCATED AT 250 WORDS)

Antiestrogen U23,469 induced alterations of catecholamine levels on plasma and central nervous system.

The effect of antiestrogen U23,469 administration in vivo on the concentration of dopamine, norepinephrine and epinephrine in the plasma, cerebral cortex and hypothalamus in ovariectomized rats was investigated. Rats were treated with estradiol benzoate, progesterone and U23,469 in different doses, s.c., daily for 6 days. Control group was injected with sesame oil. Catecholamines were estimated by radioenzymatic assay. Six days of U23,469, estradiol benzoate, progesterone or its combination altered the catecholamine levels compared to the control. Dopamine decreased in plasma with progesterone and U23,469. In the cerebral cortex, progesterone and U23,469 increased significantly and in the hypothalamus all the treatments produced a decrease of catecholamines. The levels of NE were reduced with estradiol benzoate, progesterone and U23,469; there was no significant difference in the norepinephrine levels after different treatments in the cerebral cortex, but the NE levels were significantly decreased in the hypothalamus. Epinephrine showed differences related to the treatment, as in plasma, as in cerebral cortex and hypothalamus. These results suggest that antiestrogen treatment compared with the estradiol benzoate or progesterone may affect the catecholamine levels of the central nervous system and plasma and support the idea that AE could have an indirect effect on the catecholaminergic system.

Sexual differences in the brain catecholamine content in four species of tropical bats.

The catecholamines dopamine, norepinephrine and epinephrine were studied in the brains of male and female tropical bats of four species, with different feeding habits (insectivorous, frugivorous, omnivorous and pollen eater). They were trapped in a refuge at 18 degrees 24'24''N, 99 degrees 02'08''W with a mean annual temperature of 25.8 degrees C, in a tropical deciduous forest. The three catecholamines occur in both sexes of all four species, in levels which are statistically different among species as well as between sexes. Dopamine and norepinephrine levels were higher in males than females, but the opposite occurs with epinephrine. These findings suggest that changes in catecholamine levels are intimately involved in the reproductive pattern of the species studied.

The relationship of plasma gonadotrophins and steroid concentrations to body growth in girls.

Plasma concentrations of luteinizing hormone (LH), follicle-stimulating hormone (FSH), 17 alpha-hydroxyprogesterone (17 alpha-OHP), 17 beta-oestradiol (Oe2) and progesterone (P) were measured in 352 healthy girls aged 6.0 to 15.9 years, as a function of age (CA), weight, height and calculated lean body mass (LBM) and total body fat (TBF). The earliest hormonal changes were a fall in mean plasma FSH concentrations together with a small but significant rise in plasma Oe2 well in advance of any sign of pubertal development. The next changes were a progressive rise in plasma FSH and 17 alpha-OHP concentrations without further increments in plasma Oe2; these changes corresponded to a mean body weight of 29.8 kg, a mean height of 132.0 cm (initiation of the adolescent growth spurt), a mean LBM of 24.7 kg and a mean TBF of 5.1 kg. The last events were a progressive rise in plasma LH and Oe2 and less marked in P, which occurred in association with a mean body weight of 40.0 kg, a mean height of 142.0 cm (time of peak velocity of weight and height gain), a mean LBM of 31.8 kg and a mean TBF of 9.1 kg. Significant quadratic equations were disclosed between plasma FSH and LH versus CA, weight, height and LBM, and a significant linear correlation was observed between each gonadotrophin and TBF. These results show an association, not necessarily causal, between a 'critical level' of body composition and hormonal changes at the start of the adolescent growth spurt, as well as with late hormonal events at the time of peak velocity in weight and height gain. On the other hand, LBM rather than TBF seems more closely associated with the initiation and progression of puberty.

Effect of adrenergic stimulation on insulin and proinsulin secretion. Study on patients with pheochromocytoma.

Two patients with pheochromocytoma predominantly secreting noradrenaline, were studied. Intravenous glucose tolerance tests were performed: in the preoperatory period, under alpha adrenergic blockade with pentolamine and one month after the tumor was removed. Serum glucose and insulin concentrations were determined. Proinsulin was separated from the insulin in Sephadex G-50 fine columns. In the preoperatory study, insulin secretion was less during the first 10 minutes after glucose administration, when comparing to that observed in two other studies. During pentolamine blockade, insulin secretion was at least three times higher than the preoperatory test; however, hypoglycemia was not observed. Proinsulin levels were similar to the observed in a normal individual in the pre and postoperatory test during pentolamine blockade, and were found significantly elevated. It is postulated that hypoglycemia was not produced during the late test because more than 50 per cent of immunoreactivity measured as insulin, corresponded to proinsulin whose biological activity is 10 times less than that of insulin.

Efecto de la estimulacion adrenergica sobre la secrecion de insulina y proinsulina. Estudio en pacientes con feocromocitoma. / Effect of adrenergic stimulation on insulin and proinsulin secretion. Study on patients with pheochromocytoma

Se estudiaron dos pacientes con feocromocitoma cuya secrecion predominante era noradrenalina. Se les practicaron pruebas de tolerancia endovenosa a la glucosa en el periodo preoperatorio, bajo bloqueo alfa adrenergico con pentolamina, y un mes despues de haber extirpado el tumor. Durante estas pruebas se determinaron las concentraciones sericas de glucosa e insulina. La proinsulina se separo de la insulina en columnas de Sephadex G=50 fino. Durante el estudio preoperatorio la secrecion de insulina fue menor durante los primeros 10 minutos despues de la administracion de glucosa, en comparacion con la observada en los otros dos estudios. Durante el bloqueo con pentolamina se produjo una secrecion de insulina por lo menos tres veces superior a la prueba preoperatoria a pesar de lo cual no se produjo hipoglucemia.Los porcentajes de proinsulina fueron normales en las pruebas pre y postoperatorias, en tanto que se encontraron anormalmente elevados durante el bloqueo con pentolamina. Se postula que no se produjo hipoglucemia durante esta ultima prueba porque mas de 50 por ciento de la inmunorreactividad medida como insulina correspondia a proinsulina cuya actividad biologica es 10 veces menor que la de la insulina