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Biomedical subjects

G Simbruner

Publications and source records attributed to G Simbruner.

At least 55 records · Page 3Linked to original sources

Regional heat loss in newborn infants. Part I. Heat loss in healthy newborns at various environmental temperatures.

In 17 newborn infants (gestational age 33-40 weeks, birthweight 1 100-5 560 g) heat flux (HF) from the forehead, chest and calf was measured by HF transducers and heat loss (HL) from those body regions was calculated, taking into account variations in surface area. Both HF and HL were related to operative environmental temperature (Top). Average HF from the forehead, chest and calf was 63.3, 51.5 and 45.7 W/m2 respectively at a Top of 31.2 degrees C and increased by 100%, 66% and 50% as the Top fell to 27.5 degrees C. HL from the head, trunk and limbs contributed about one-third each to total dry HL. These data, in the form of regression equations, permit assessment of heat loss from the various body regions of individual neonates in any thermal environment.

Body Temperature Regulation↗

Regional heat loss in newborn infants. Part II. Heat loss in newborns with various diseases--a method of assessing local metabolism and perfusion.

Heat flux (HF) from the head, trunk and limbs of 6 neonates with various abnormalities was measured with HF transducers to find out whether the regional HF pattern reflected the metabolic and/or circulatory status of a neonate, his brain or limbs sufficiently to be of clinical use. The increased HF from all body sites in 2 infants receiving orciprenaline reflected the raised metabolism. The increased HF from the head and trunk together with decreased HF from the limbs in infants with the hypoplastic left heart syndrome reflected the degree of centralization of the circulation. The decreased HF from the head of infants with microcephalus and internal hydrocephalus indicated the diminished metabolic activity of the underlying brain. HF from the limbs, related to HF from central body parts, was useful in assessing peripheral perfusion. It might be possible to develop measurement of regional HF into a method of determining local metabolism and perfusion.

Body Temperature Regulation↗

Hepatitis B vaccination and immune response in children with malignant diseases.

Fifty children with malignant diseases were vaccinated against hepatitis B. Twenty-nine children suffered from leukaemia or non-Hodgkin's lymphoma; 14 of these were on intensive chemotherapy (group I) and 15 were without intensive therapy (group II). The other 21 children had various forms of solid tumours, 14 of them were on intensive therapy (group III) and 7 were without intensive therapy (group IV). To evaluate the immune response, we determined antibody titres over a period of more than 14 weeks after the first vaccination. As 22 out of 50 patients had received passive immunisation together with either the first or the first and second vaccination, antibody titres at the 14th and 18th week (i.e. more than 10 weeks after passive immunisation) were used to evaluate the vaccination results. An antibody titre of greater than or equal to 10 mIU/ml was considered to be a positive response. All patients of group IV, but only 4 out of 14 in group III, 4 out of 15 in group II, and 0 out of 14 in group I produced antibody titres higher than 50 mIU/ml. In contrast to the full response in group IV, two-thirds of all other patients had no immune response (less than 10 mIU/ml). Based on our experience we recommend vaccinating patients suffering from solid tumours and receiving no intensive therapy (group IV) against hepatitis B and protecting all the other children with malignant diseases by passive immunisation, if necessary.

Adolescent↗

Discrimination of taste and preference for sweet in premature babies.

A modified method for registering non-nutritive sucking behaviour with and without taste stimulation enabled us to study taste perception of premature babies. We wanted to study how babies who had no extrauterine taste experience reacted to one or more stimuli with water and 33% glucose. Eight randomly selected healthy newborns (three of them being SGA without further symptoms), exclusively fed by gastric tube, were studied. The mean gestational age at the time of the study was 35.5 weeks. They were studied five times with water and five times with glucose just before feeding. In seven babies the sucking response to glucose was greater than that to water from the first trial onwards. Sucking response increased with repeated glucose stimulation, but remained the same with water stimulation. The eighth baby behaved completely differently. We concluded from our results that premature babies with a postconceptional age of 35 weeks can discriminate between sweet and not-sweet. The greater sucking response to glucose than to water at the first trial implies a genetic factor in the preference for sweet in humans.

Discrimination, Psychological↗

Comparison of chest radiography and static respiratory compliance in the assessment of the severity of pulmonary diseases in newborns with respiratory distress.

In 55 newborn infants with respiratory distress syndrome (RDS) we compared chest radiographs and static respiratory compliance to see which of the two methods would best characterize the severity of pulmonary disease. There was a significant correlation between radiological score and compliance (rs = -0.5776, n = 55, p less than 0.001). Healthy newborns, newborns with RDS who did not need artificial ventilation and those newborns who needed respirator treatment had significantly different values of radiological score and compliance. RDS may be differentiated into groups of diagnoses. Newborns with HMD could be separated from those with wet lung syndrome or aspiration pneumonia by analyzing the radiogram or measuring the compliance. When survivors are compared with those newborns who died, the static respiratory compliance alone could predict the final outcome.

Humans↗

[lst report: Alternatives to cortisone therapy. lst clinical experiences with a carnitine-betamethasone combination for the stimulation of fetal lung maturity].

In the recent past criticism has been voiced with regard to the efficacy and possible side effects of corticosteroid prophylaxis of fetal respiratory distress syndrome (RDS). Apparently the efficacy of this treatment has been over-estimated and the spectrum of possible side effects has not received enough critical attention. In view of the multiple indications that the fetal metabolism, above all, may be altered by this type of therapy, it seems necessary to search for other methods of surfactant stimulation. This paper presents the first clinical study on the use of carnitine (4 g for 5 days in combination with twice 8 mg beta-methasone versus twice 8 mg betamethasone alone). The patients on combination therapy showed a more marked increase in surfactant content of the amniotic fluid. Lung compliance determination in infants born within 72 hours of completion of therapy also revealed better results in the combination therapy group. There were also fewer clinically demonstrable RDS cases in this group. More research will be necessary to definitely establish the value of this new form of therapy.

Animals↗

Heat flux from the fetal scalp during labor and fetal outcome.

In 40 deliveries a new variable, heat flux from the fetal scalp, was recorded and correlated with fetal outcome. The heat flux from the fetus, which reflects the temperature gradient between the warmer fetus and the mother was measured by a transducer attached to the fetal scalp after rupture of the membranes. In the last 20 min before delivery we found a statistically significant correlation (p less than 0.05) between heat flux from the fetus and pH of umbilical artery blood. Heat flux in the group with higher pH differed significantly from those with lower pH. We conclude that heat flux measurements could be developed and used for fetal monitoring.

Body Temperature↗

Neonatal nesidioblastosis--diagnosis and preoperative management.

Two infants were admitted for severe, intractable hypoglycemia. "Fasting" tests lasting 45 and 30 minutes respectively revealed hypoglycemia with inappropriately elevated levels of plasma insulin and plasma C-peptide. Subsequently, somatostatin was infused to test the individual sensitivity of the B-cells. Basal and glucose-induced insulin and C-peptide secretion were significantly reduced. Preoperative treatment with somatostatin was introduced, which controlled the hypoglycemia. In both patients, subtotal pancreatectomy was effective in restoring normal glucose homeostasis.

Blood Glucose↗

Relationships among human amniotic fluid dipalmitoyl lecithin, postpartum respiratory compliance, and neonatal respiratory distress syndrome.

The major molecular species of amniotic fluid phosphatidylcholine were determined as diacylglycerol trimethylsilyl ether derivatives by gas-liquid chromatography with use of glass capillary columns. We studied amniotic fluid specimens from 48 pregnancies. As expected, the major disaturated species of amniotic fluid phosphatidylcholine, dipalmitoylphosphatidylcholine, and palmitoylmyristoylphosphatidylcholine increased with gestational age, whereas phosphatidylcholine species with 34, 36, and 38 carbon atoms in the acyl radicals decreased. Although the amniotic fluid samples were obtained shortly before parturition (4.2 +/- 3.7 h, mean +/- SD), the correlation between dipalmitoylphosphatidylcholine concentration in amniotic fluid and gestational age was better than between dipalmitoylphosphatidylcholine concentration and the compliance of the respiratory system of the newborns. In addition, the percentage of amniotic fluid phosphatidylcholine species present as dipalmitoylphosphatidylcholine seemed to be a more reliable predictor of lung maturity than was the absolute dipalmitoylphosphatidylcholine concentration in amniotic fluid.

Amniotic Fluid↗

[The determination of oxygen consumption from temperature measurements with the use of a thermodynamic model ].

A thermodynamic model is described which allows to calculate the oxygen consumption from 4 temperatures as input-variables. These input-variables are: one core-temperature (Tesoph), two skin-temperatures (one at the chest, one at the calf) and the incubator-air temperature. This model is based on the close relationship between oxygen consumption and heat production. The rate of heat production is derived from heat loss to the environment plus heat storage in the body. The data are smoothened by a special mathematical procedure and processed by a HP-85 Computer. Oxygen consumption was synchronously determined by the thermodynamic model and by a conventional method 155 times in four newborns. The flow-through method was used as conventional reference method. The results show that the thermodynamic model yields values for oxygen consumption which are closely related to directly measured values; which indicate the increase in oxygen consumption with activity and decreased environmental temperature; and which follow rapid changes in oxygen consumption of 5 ml/kg per minute. Consequently this thermodynamic model seems suitable to predict the relative changes in oxygen consumption. However the absolute values of oxygen consumption obtained by the model and obtained by direct measurement differ by 5 to 25% the thermodynamic model yielding systematically higher values than the direct measurement. The reasons for this difference are discussed. We demonstrated that a maximum of reliable information can be obtained from a minimal number of measuring sites on the patient by using a theoretical-analytical model.

Body Height↗

[Thyroid function in healthy premature infants and in premature infants with the hyaline membrane syndrome ].

The serum concentrations of thyrotropin (TSH), thyroxine (T4), trijodothyronine (T3) and of 3,3',5', trijodothyronine (reverse T3, rT3) were followed up during the first 4 weeks of life in 5 healthy premature infants and in 6 premature infants with hyaline membrane syndrome and artificial ventilation. TSH and T4 concentrations remained unchanged in both groups. T3 levels increased during the observation period and were significantly lower in the sick prematures on days 1 and 3 (p less than 0,02). T3 and the rT3/T3 ratio was increased in healthy and in the sick prematures, the sick prematures showing higher values, and decreased in both groups during the first week of life. We found no significant correlation between TSH and the peripheral thyroid hormone levels as well as no relation between the respiratory compliance-indicating degree of lung maturity-and the T3 or T4 concentrations. Postpartal T3 or T4 serum levels were correlated significantly with the duration of artificial ventilation. Our data indicate that a "low T3 syndrome" was present in all prematures after birth and that respiratory distress syndrome increased conversion of T4 to rT3. From our results we cannot conclude that substitution therapy with thyroid hormones may be useful in premature infants with the hyaline membrane syndrome.

Humans↗

[Radiological examination of the thoracic organs for persistent foetal circulation (author's transl)].

The radiological changes seen on chest x-rays of five children with persistent foetal circulation are analysed. There is inconstant cardiac enlargement and a reticulo-nodular appearance of the lungs, indicating interstitial oedema with heart failure. The value of the chest x-ray consists mainly in excluding a pulmonary or a characteristic cardiac abnormality as a cause of dyspnoea; it does not provide direct diagnostic information.

Angiocardiography↗

Respiratory compliance of newborns after birth and its prognostic value for the course and outcome of respiratory disease.

The compliance of the respiratory system was determined at an average of 2.89 h (range 45 min - 8 h) after birth in 82 newborns who were retrospectively divided into group 1: healthy newborns (mean gestational age 37.1 weeks, range 30 - 41 weeks); group 2: newborns with respiratory distress (RD) needing no ventilatory support (mean gestational age 37.3 weeks, range 35--40 weeks); group 3: newborns with RD needing ventilatory support and surviving (mean gestational age 34.3 weeks, range 30--39 weeks), and group 4: newborns with RD who needed ventilatory support and died (mean gestational age 30.8 weeks, range 28--37 weeks). Respiratory compliance was measured by the airway occlusion technique in spontaneously breathing babies and by injecting a known volume of gas into the closed airway system and measuring airway pressure in intubated babies. The difference in postnatal compliance was statistically significant (p less than 0.01) in those four groups and was correlated with the severity of the disease in groups 2 and 3. In infants with RD, compliance was highly predictive for the need for ventilatory support (93% correct and 7% erroneous) and in infants with ventilatory support, for the mortality (83% correct and 17% erroneous). We conclude that postnatal compliance measurements are very useful to predict the course and outcome as well as to classify the severity of RD.

Gestational Age↗

Relationship between peripheral blood flow and blood temperatures in lambs during hypoxemia and hemorrhage.

The relationships between the peripheral blood flow and arterial and venous blood temperatures were examined in 5 lambs (mean weight 10.5 kg, 4-12 weeks old) during hypoxemia and hemorrhage. Blood flow to one hind limb was measured continuously with an electromagnetic flow transducer around the femoral artery. Aortic and venous blood temperatures were monitored by means of thermistor catheters in the descending aorta and iliac vein. The intravascular catheters and flow transducer were implanted chronically and all studies were performed in conscious lambs, resting quietly. Skin temperatures were recorded at the hip and at the foot. The total heat in the hind limb (Htot), the net heat transported by circulating blood (Hbl), and the metabolic heat produced in the hind limb were calculated. The arterial and venous blood temperature were related to peripheral blood flow. When the flow was constant over a control period, blood temperatures remained constant. Hypoxemia, produced by administering a low oxygen gas mixture to the lamb, did not alter femoral blood flow, nor did it affect vascular temperatures. During hemorrhage, femoral blood flow fell, arterial temperature rose by 0.46 degrees C and venous temperature by 0.85 degrees C; arteriovenous temperature difference decreased from 0.85 to 0.44 degrees C. There was an inverse relationship between femoral blood flow and venous temperature in each individual lamb subjected to hemorrhage, with a correlation of 0.91. For each 10-ml/min decrease in peripheral blood flow the venous temperature rose an average of 0.33 degrees C. Changes in peripheral blood flow were immediately reflected by changes in the venous temperature.

Animals↗