The response of newborn sheep to TRH with and without somatostatin.

Hormone responses to a bolus injection of thyrotropin releasing hormone (TRH) were studied in 8 newborn lambs between 6 and 19 hours of age. The effect of a bolus injection and 45 min infusion of somatostatin (SRIF) on these responses was studied in 2 other animals. Serial measurements of serum TSH, prolactin, triiodothyronine (T3) and thyroxine (T4) were conducted for 2 to 6 h in all animals. Mean baseline T4 and T3 concentrations were 12.6 microng/dl and 221 ng/dl, respectively, both significantly higher than values in fetal or adult animals. These high values were due to the events of parturition. In spite of the high baseline T4 and T3 levels, there were rapid and significant increases in both TSH and prolactin concentrations in response to TRH alone. The TSH response evoked further increments in serum T3 and T4 concentrations observed at 30 min and 60 min, respectively, both subsequently increasing progressively through 6 h. During the 45 min period of SRIF infusion, the TSH T4 and T3 responses to the zero time TRH injection were minimal. However, after discontinuing SRIF, late increases in TSH, T4 and T3 were observed. The results indicate that the hyperiodothyroninemia characteristic of the newborn period does not block the response to exogenous TRH, whereas the inhibitory effect of exogenous SRIF is observed in the newborn as in the adult. The increased endogenous TRH secretion presumably responsible for the neonatal TSH surge may be overriding the negative feedback effect of thyroid hormones.

Exchange transfusion in the neonate: a controlled study using frozen-stored erythrocytes resuspended in plasma.

During a nine-month period 43 consecutive infants who needed exchange transfusions for the management of their hyperbilirubinemia randomly received whole blood less than 5 days old (control group) or frozen erythrocytes diluted in plasma (experimental groups). There was no different prior to and after exchange transfusions in total protein, albumin, globulin, immunoglobulins, bilirubin, and hematocrit in the control group versus the experimental group. The efficacies of bilirubin removal, as measured by delta bilirubin, were the same in the two groups. Advantages of exchange transfusion with freeze-preserved erythrocytes suspended in type-specific plasma are discussed.

Chronic polymicrobial bacteremia.

A 13-year-old girl had chronic polymicrobial bacteremia with Enterobacter hafnia and Enterobacter agglomerans in the absence of any demonstrable underlying illness, use of immunosuppressive drugs, or discovery of portal of entry of the bacteria. She was treated successfully with a prolonged course of carbenicillin and aminoglycoside antibiotics which were tolerated well. The only side effect of the therapy was a transient episode of vestibular dysfunction which was reversible following cessation of gentamicin. The principles of management of polymicrobial bacteremia are presented.

Treatment of neonatal hypoglycemia with continuous intravenous glucose infusion.

The treatment of neonatal hypoglycemia by constant infusion of glucose at the rate of 8 mg/kg/minute was studied in 22 hypoglycemic neonates. In 18 neonates glucose levels rose above the hypoglycemic range within ten minutes of infusion and in three, within 30 to 50 minutes of infusion. The remaining neonate had hyperinsulinemia and responded only to diazoxide. Constant glucose infusion was found to be useful therapeutically for neonatal hypoglycemia.

Control of juvenile diabetes mellitus and its relationship to endogenous insulin secretion as measured by C-peptide immunoreactivity.

Proinsulin is converted to insulin and C-peptide in the pancreatic beta-cells; the latter two peptides are secreted in equimolar concentrations. Thus measurements of C-peptide immunoreactivity may provide a means of assessing residual pancreatic function in insulin-treated diabetic patients. Thirty-five patients with a mean (+/- SE) age of 13.4 +/- .6 years who had diabetes mellitus for 4.8 +/- .3 years were included in this study. Glucose and CPR were measured in the fasting state and one hour after 1 gm/kg (maximum 50 gm) of oral and glucose. Patients were assigned to one of two groups on the basis of adequate or poor control of diabetes. Twenty-five of the 35 (71%) patients had evidence of endogenous beta-cell function, i.e., CPR greater than 0.5 ng/ml. CPR levels over 0.5 ng/ml were present in a significantly (p less than 0.05) greater number of patients with diabetes of less than 5 years duration (19/21) than in those with diabetes greater than 5 years duration (6/14). Only one patient showed a rise in CPR after the glucose load. All patients with CPR greater than 2.0 ng/ml were in the adequately controlled groups, but there were patients with CPR less than 2.0 ng/ml in both adequately and poorly controlled groups. Because the CPR value includes both C-peptide and antibody-bound proinsulin, separate determination of free C-peptide was done in 30 patients. These results confirmed the conclusions based on CPR estimation. Although growth hormone values were higher in patients in the poorly controlled group, there was no correlation between hGH and CPR. We conclude that residual insulin secretion in diabetic patients may facilitate good control, but that low CPR values and hence absent beta-cell reserve is not always associated with poor control.

Possible mechanisms and significance of the neonatal surge in glucagon secretion: studies in newborn lambs.

Studies were conducted in newborn lambs to gain insight into the significance and mechanism(s) responsible for the rapid rise in plasma immunoreactive glucagon (IRG) which occurs in human and other newborn species immediately after delivery. Three sets of experiments were conducted: group A, control studies (n = 5) in which delivery into room air was followed 1 hr later by cutting of the umbilical cord and periodic blood sampling for a further hour; group B, studies (n = 5) in which somatostatin (SRIF), a known inhibitor of IRG and insulin (IRI) secretion, was infused int othe fetus for 10 min before, and for 1 hr after delivery and immediate cord cutting; group C, studies (n = 5) in which an identical dose regimen of SRIF was infused into fasting newborn lambs aged 24-72 hr. The doses of SRIF used were several fold higher than those proven to suppres pancreatic hormones secretion in other species. In the control studies, plasma IRG levels remained stable until the cord was cut, after which event levels rose 5-6-fold (59 +/- 15 pg/ml to 305 +/- 98 pg/ml, P less than 0.05). Simultaneously, plasma free fatty acid (FFA) concentrations rose significantly (280 +/- 80 to 780 +/- 100 muEq/liter, P less than 0.05) and IRI remained unchanged. Plasma glucose concentrations, however, in contrast to observations in other species, did not fall, and therefore, hypoglycemia was not the stimulus for the glucagon surge. SRIF infusion at birth (group B) did not prevent the rise in IRG. Again blood glucose values did not fall, but in contrast to the control studies plasma IRI levels rose and the rise in FFA did not occur. Later SRIF infusion (group C) resulted a prompt and sustained suppression of IRG and IRI and a significant fall in blood glucose. These results suggest that an adrenergic mechanism rather than curtailment of nutrients is the major stimulus to the neonatal surge in IRG.

Cateterismo de vasos umbilicais em recem-nato. Experiencia em 202 casos. / Umbilical vessels catheterization in newborn infants: experience in 202 cases

O uso de cateterismo de vasos umbilicais e frequente no periodo neonatal. Numa analise de 183 cateterismos arteriais, 19 venosos, 15 combinados e dois temporais observamos como complicacao mais frequente a cianose transitoria de pododactilos espasmo ou cianose transitoria de membros inferiores. Em nenhum recem-nato (RN) houve perfuracao intestinal ou hipertensao reno-vascular durante a internacao.Um RN apresentou perfuracao arterial umbilical com choque hemorragico e morte.A conduta diagnostica e terapeutica neste caso e discutida assim como os demais achados anatomoclinicos