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Biomedical subjects

K Betke

Publications and source records attributed to K Betke.

At least 19 recordsLinked to original sources
PubMed1991

New hearing threshold measurements for pure tones under free-field listening conditions.

Hearing thresholds for pure tones were measured under free-field listening conditions in the frequency range of 40 Hz-15 kHz. Results are consistent with the standard threshold specified in ISO 226 for frequencies up to 250 Hz, but a few dB below the ISO curve at higher frequencies. Thresholds are distributed normally on a logarithmic level scale with a standard deviation of approximately 5 dB. No significant differences between thresholds of male and female subjects were observed.

Audiometry, Pure-Tone↗
PubMed1987

Haemoglobin A2 in newborn infants of different maturity.

From 70 infants born after gestation periods of 28-41 weeks HbF and HbA2 were determined in the cord blood; HbA was calculated from the two values. HbF decreased with maturity, HbA and HbA2 increased. The percentage of HbA2 calculated from the sum of HbA + HbA2 (non-fetal Hb) increased from 0.57% to 0.83% with maturity. These values are much lower than those in adult controls (1.83%). The results show that during development the synthesis of the delta-globin chains lags behind that of the beta-globin chains. This is remarkable considering the location of the delta-globin gene within the beta-globin like gene cluster.

Fetal Blood↗
PubMed1979

[Visceral leishmaniasis (Kala-Azar) in a 3-year-old German infant (author's transl)].

The article reports on a case of visceral leishmaniasis in a 3-year-old child of German residents in Rome who had passed two vacations on the isle of Ischia. Initial signs were intermittent temperatures, marked anorexia, hepatosplenomegaly and pancytopenia, with spontaneous recovery after three weeks. At that time, leishmania serology was already positive, whereas no leishmania were found in several bone marrow preparations despite a most thorough search. During the following eight weeks, the patient had chickenpox and mumps. During the mumps, relapse of the visceral leishmaniasis occurred, associated with a dramatic increase of the hepatosplenomegaly and recurring pancytopenia. It was only now that we could discover multiple leishmania infection of the bone marrow. Subsequent therapy with sodium stibogluconate (Pentostam) was effective without any complications, and eventually cured the patient.

Antimony Sodium Gluconate↗
PubMed1978

Association of neonatal respiratory distress with birth asphyxia and deficiency of red cell mass in premature infants.

Red cell mass (RCM) was estimated using 125I-labelled human serum albumin in 128 premature infants born after 26 to 36 weeks gestation. Infants of three different gestational periods (26--29, 30--32, and 33--36 weeks) with respiratory distress (RD) averaged lower one-minute Apgar scores and lower RCM than infants without RD (P less than 0.05). The incidence of RD was significantly (P less than 0.05) higher in infants with Apgar scores below 6 and in infants with RCM of less than 35 ml/kg than in the infants with greater values. The highest incidence of RD and the highest mortality rate were found in the infants with low Apgar scores and low RCM values. Prematures with similar Apgar scores showed a higher incidence of RD when RCM was low, and infants with similar RCM showed a higher incidence of RD when Apgar scores were low. Our results suggest that both birth asphyxia and deficiency of red cell mass interfere with postnatal cardio-respiratory adaptation. In high-risk premature infants, erythrocytes should be transfused when the venous haematocrit is below 0.459

Anemia↗
PubMed1978

Peripheral circulation in the newborn: interaction of peripheral blood flow, blood pressure, blood volume, and blood viscosity.

Peripheral blood flow and systolic blood pressure (strain-gauge plethysmograph), blood volume (Evans blue) and whole blood viscosity (cone-plate viscometer) have been measured in 66 premature and full-term infants 6 to 144h of age. Blood flow and blood volume were moderately decreased in the infants with respiratory distress. Highly significant (P less than 0.001) correlations were found between blood flow and blood volume (r = 0.77), blood pressure and blood volume (r = 0.50), peripheral resistance and blood volume (r = -0.44), blood flow and blood pressure (r = 0.50), blood flow and peripheral resistance (r = -0.67), peripheral resistance and blood viscosity (r = 0.45), and blood viscosity and haematocrit (r = 0.86). There was no correlation between peripheral blood flow and blood viscosity. However, at given blood volume, peripheral blood flow decreased with increasing blood viscosity. These results indicate that in newborn infants peripheral blood flow, blood pressure and peripheral resistance are influenced by blood volume, but also depend on blood viscosity.

Blood Circulation↗
PubMed1978

Blood volume of children with leukemia.

Blood volume was measured using 125iodinated human serum albumin in 27 children with acute lymphoblastic leukemia, and in 7 children with various types of leukemia. Total blood volume was normal in patients without marked enlargement of spleen and liver, and increased progressively as spleen and liver size increased. The hypervolemia was entirely due to expansion of plasma volume. In the children with marked hepatosplenomegaly, only hematocrit (but not red cell mass) was below the normal range in most cases. Both hematocrit and red cell mass were subnormal in the majority of patients without considerably enlarged spleen and liver. Therefore, anemia in children with marked hepatosplenomegaly may be partly caused by hemodilution of red blood cells in expanded plasma volume.

Adolescent↗
PubMed1977

Capillary-venous hematocrit differences in newborn infants. I. Relationship to blood volume, peripheral blood flow, and acid base parameters.

Venous and capillary hematocrit, acid base values, and circulatory parameters were measured simultaneously in 92 newborn infants within six hours of birth. Gestational age ranged from 26 to 41 weeks. The capillary/venous hematocrit ratio (Hctc/Hctv) was greater than 1.00 in 89 infants. We found significant inverse correlations between Hctc/Hctv and several parameters, such as pH (r = -0.82), standard bicarbonate (r = -0.73), systolic blood pressure (r = -0.51), and peripheral blood flow (r = -0.70). Most of the infants with a Hctc/Hctv of 1.20 and above had red cell mass values of less than 35 ml/kg. However, blood volume apparently did not influence the Hctc/Hctv. Gestational age appeared to affect Hctc/Hctv only before 30 weeks, when compared with the Hctc/Hctv of term infants. Our results indicate that disturbed circulation, and in particular, disturbed microcirculation is involved in the development of high Hctc/Hctv ratios. We strongly advise that hematocrits obtained by skin prick from a sick newborn infant should not be relied on as they may give misleading information on oxygen carrying capacity to vital organs.

Acid-Base Equilibrium↗
PubMed1977

Estimation and prediction of blood volume in infants and children.

Blood volume was studied in 160 infants and children aged from one hour to 14 years. From these data linear and logarithmic regression equations relating blood volume to weight, height and surface area were calculated. Equations utilizing combined weight and logarithmic weight values were found to be the most accurate for predicting blood volume. Therefore, nomograms were constructed for reading blood volume directly from height and weight.

Adolescent↗
PubMed1977

[School stress].

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Child↗