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Biomedical subjects

L Havelec

Publications and source records attributed to L Havelec.

At least 73 records · Page 4Linked to original sources
PubMed1977

[The IQ of heterozygotes for phenylketonuria (PKU). indication of a blood phenylalanine-independent action of the PKU mutant (author's transl)].

The IQ of parents of phenylketonuria-(PKU-)affected children is lower than that of parents with histidinemia-affected children (control group). The difference arises almost entirely from the verbal part of the Hamburg-Wechsler test. The IQ of the parents with histidinemia-affected children shows the same distribution as that of the normal population; heterozygosity for this condition does not appear to confer any intellectual advantage. In PKU patients treated at an early age and apparently adequately, a slight, but significant decrease in IQ becomes apparent between the ages of 6 and 8 years. This slight decrease also refers mainly to the verbal IQ. At 4 years of age all PKU patients are tested with Bühler-Hetzer, as well as the Kramer test. There is a significant difference between the results in favour of the Bühler-Hetzer test, which is much less verbal. Since heterozygotes for PKU never show elevated blood phenylalanine levels and, moreover, prenatal tyrosine deficiency, as argued by others, seems highly improbable, it is supposed that the PKU gene has a more direct influence on certain ganglion cells at least, with a consequent slight, but significant lowering of the verbal IQ in heterozygotes and satisfactorily-treated homozygotes for PKU. A slightly increased intracellular phenylalanine concentration in heterozygotes and apparently adequately-treated homozygotes need not to be reflected in raised blood levels and this could be an explanation for the observed IQ lowering. But it should not be overlooked that by far the greatest part of damage in PKU patients is caused by chronic phenylalanine poisoning which is well preventable by correct dietary treatment.

Adult↗
PubMed1977

Intellectual level (IQ) in heterozygotes for phenylketonuria (PKU). Is the PKU gene also acting by means other than phenylalanine-blood level elevation?

There is a statistically significant difference in the IQ's of PKU and histidinemia parents. The difference is due entirely to the verbal part of the Hamburg-Wechsler test. There is no significant difference in performance. The heterozygous state of histidinemia does not seem to bear an intellectual (evolutionary) advantage, since the IQ's of histidinemia parents show the same distribution as a normal population. In early and mostly well-treated PKU patients, the same slight deficit in verbal IQ appears with increasing age (changing test methods). These patients, simultaneously tested at 4 years of age with the Bühler-Hetzer and Kramer tests, exhibit a statistically significant difference between the results in favor of the less verbal Bühler-Hetzer. Since heterozygots for PKU never have elevated phenylalanine blood levels, and because tryosine deficiency as argued by others seems highly improbable, we believe that the PKU gene has a more direct action on (or in) at least certain ganglion cells, lowering the verbal IQ slightly but significantly. This action is not reflected by phenylalanine increase in the extracellular space in heterozygots and is not abolished by dietary treatment in homozygous PKU patients. The major damage in PKU patients must be due to chronic phenylalanine poisoning, which deteriorates cells and/or functions on a much larger scale, because it can be easily prevented by decreasing the phenylalanine blood level with correct dietary treatment.

Amino Acid Metabolism, Inborn Errors↗
PubMed1977

[Characteristic features of ischaemic strokes in young adults (author's transl)].

Clinical symptoms, angiographic findings and risk factors were recorded according to a classification system in 28 women and 39 men who suffered an ischaemic cerebral stroke before the age of 40. This enabled correlations to be made within the group of young patients and the discovery--by comparison with a corresponding group of patients over 40--of statistically significant age-specific features of cerebro-vascular disease. Vascular lesions in young patients show a sex-specific distribution and a characteristic relationship to clinical symptoms. The prognosis is more favorable in young patients; risk factors which predispose to stroke and influence its further development are less frequent. It is, therefore, suggested that characteristic features of strokes in young adults can be partially explained by the fact that they are usually caused by single pathological alterations in otherwise healthy persons.

Adult↗
PubMed1977

Long-term prognosis in stroke related to cerebral blood flow.

In 180 patients, cerebral blood flow was measured between one and six weeks after acute cerebrovascular ischemia. Patients were grouped according to their clinical deficits at the time of blood flow study. Statistical analysis revealed highly significant differences among the flow values of the groups. The patients were followed up for a period of up to 6 years (mean, 34 months) after the attack, and then regrouped. In these groups, the statistical significances of differences among the flow values was even higher. Patients also were grouped according to changes in neurologic status, and again the flow values differed significantly among the groups. The results show significant relationships among flow values after cerebrovascular ischemia and neurologic deficits, change in status, and the final functional state. Cerebral blood flow measurement together with other clinical signs permits an estimation of a patient's chance for functional recovery after a stroke.

Adolescent↗
PubMed1977

[Timing of a letal intracranial hemorrhage by means of the HbA/HbF ratio (author's transl)].

Possibilities and limits of the method for timing an intracranial hemorrhage by means of the HbA/HbF erythrocyte ratio are investigated in six newborns. The effect of labeling HbF erythrocyte containing newborn blood by transfusion and exchange transfusion of HbA erythrocyte containing donor blood as well as "self-labeling" after the first transfusion as a result of HbA--and HbF erythrocytes decaying at a different rate, is described. If a coagulum can be clearly allocated to the blood where it originates from, depends a) on the alteration of the HbA/HbF erythrocyte ratio by the above mentioned ways of labeling and b) on the size of the sample i.e. on the number of erythrocytes counted to determine the HbA/HbF erythrocyte ratio. The confidence limits of the HbA/HbF erythrocyte ratio for a given number of counted erythrocytes have been determined. It was taken into account whether the blood was labelled by a transfusion or by "self-labeling". The analysis of the period before, during and after the intracranial hemorrhage made a preliminary evaluation of etiological factors and some symptoms possible. The hypothesis that sodium bicarbonate dosages of 8 mEqu/kg/24 h are an important cause of intracranial hemorrhage has to be rejected on the grounds of this study's results.

Cerebral Hemorrhage↗
PubMed1976

[Effect of Ouabain on cerebral blood flow (author's transl)].

The effect of 0.25 mg ouabain on cerebral blood flow (CBF) was investigated in patients with and without cerebrovascular disease using the xenon clearance method. The 36 patients included in this study did not show any signs of heart failure. Ouabain increased the CBF and this effect was demonstrable 15, as well as 90 min. after administration. This effect was proven statistically using the t-test for a comparison of the values with spontaneous changes in a control group without medication. The perfusion of pathologically-supplied brain regions was altered in the same way as the hemispheric flow; changes in the distribution of blood in the way of a steal effect were not observed. The haemodynamic parameters do not indicate a primary cardiac effect. Hence, an influence of ouabain on cerebral vessels might be responsible. The present results support reported clinical experience with ouabain for the treatment of patients with cerebrosvascular disease.

Blood Pressure↗
PubMed1975

[Female constitution and tolerance of pills (author's transl)].

In a retrospective study on 526 patients in a family-planning clinic the significance of physical constitution type and pill-tolerance was examined. If only one type of pill was administered statistically significant differences in the tolerance were not evident. When several types of pills were tried because of undesirable side-effects of a single pill a significantly higher tolerance of pills with a balanced hormone-composition could be demonstrated. The latter kind of pills was better tolerated by students than by salaried employees. This could be explained by an increased readiness for family-planning among undergraduate students. A correlation between physical constitution and pill tolerance could not be found in this statistical analysis and the widespread use of this criterion is questioned by the authors.

Body Constitution↗
PubMed1975

[Results of a follow up study of small for date babies. I. Physical development (author's transl)].

74 small for date babies were investigated at the age of 10 years. The first part of the paper deals with the children's physical development and state of health. An attempt to correlate the degree of intrauterine malnutrition and postnatal development was made taking into account possible etiological factors, genetic, pre- and postnatal influences. Four children who had been exposed to several harmful intrauterine factors showed general developmental retardation. All the other childrens demonstrated normal physical development including the group who had shown signs of prolonged intrauterine malnutrition.

Adult↗
PubMed1975

[Results of a follow up study of small for date babies. II. Mental development (author's transl)].

The second part of the follow-up investigation of 74 small for date babies presents the results of neurological investigation and psychological testing. A correlation was found between the period of the intrauterine noxa and the results. A third of the children in group I (where the intrauterine influences were more severe and more prolonged) had an IQ below average. Minor cerebral damage, poor school performance and mental disturbance were significantly more common than in group II. The EEG-investigation did not contribute additional information. In both groups social factors had an important influence.

Body Height↗