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Biomedical subjects

H Howald

Publications and source records attributed to H Howald.

At least 55 records · Page 3Linked to original sources
PubMed1986

Neurological prognosis of high-risk preterm infants with peri-intraventricular hemorrhage and ventricular dilatation.

Fifty-eight preterm neonates evaluated by real-time sonographic scanning of the head were prospectively studied. They were divided into three groups: 13 with peri-intraventricular hemorrhage (PIVH) alone, 19 with subsequent ventricular dilatation and 26 control infants without ultrasound evidence of PIVH. At 12 months of age detailed neurological follow-up assessment was carried out. Five (8.6%) patients had major handicaps, 34 minor neurological abnormalities. The severity of the PIVH correlated with the neurologic outcome (p less than 0.02). The incidence of major handicaps was significantly greater in the group with ventricular dilatation (p less than 0.03). Among the infants with PIVH, major handicaps were only present if associated with grade III and IV. Severe posthemorrhagic ventricular dilatation increased the risk for major handicaps. Adverse neurological sequelae at follow-up appeared to be attributable to the extent of PIVH and aggravated by severe ventricular enlargement.

Brain Diseases↗
PubMed1986

Fetal ventriculomegaly, agenesis of the corpus callosum and chromosomal translocation--case report.

Real-time ultrasound was used to evaluate intracranial anatomy and ventricular size in a child with fetal ventriculomegaly. It was associated with agenesis of the corpus callosum and chromosomal translocation. Serial measurements of cerebral ventricular dilatation at various gestational age may improve perinatal management of the newborn with fetal ventricular enlargement.

Agenesis of Corpus Callosum↗
PubMed1986

Obstructive ventriculomegaly.

Intracranial Hemorrhage (ICH) occurs primarily in premature infants, and post-hemorrhagic ventricular dilatation is a well-known complication in this age-group. Blood clots within the ventricle are diagnostic of ICH but not usually seen. In our case Real-Time Ultrasonography has proved to be very helpful to identify intraventricular hematomas and to control obstructive ventriculomegaly without therapeutic intervention.

Cerebral Hemorrhage↗
PubMed1985

Influences of endurance training on the ultrastructural composition of the different muscle fiber types in humans.

To investigate changes in the ultrastructure of the different muscle fiber types induced by endurance training ten sedentary subjects (five women and five men) were exercised on bicycle ergometers 5 times a week for 30 min. After 6 weeks of training there were significant changes in VO2max (+14%), in the percentage of type I (+12%) and type IIB fibers (-24%) as well as in the volume densities of mitochondria. The latter increased 35% in type I, 55% in type IIA and 35% in type IIB fibers. The relative increase in subsarcolemmal mitochondria was larger than in interfibrillar mitochondria in all fiber types. There was also a significant increase in the volume density of intracellular lipid in type II fibres. It is concluded that high intensity endurance training leads to an enhancement of the oxidative capacity in all muscle fiber types.

Adult↗
PubMed1985

Transfer effects in endurance exercise. Adaptations in trained and untrained muscles.

The effects of 8 weeks of bicycle endurance training (5 X /week for 30 min) on maximal oxygen uptake capacity (VO2max) during arm and leg ergometry, and on the ultrastructure of an untrained arm muscle (m. deltoideus), and a trained leg muscle (m. vastus lateralis) were studied. With the training, leg-VO2max for bicycling increased by +13%, while the capillary per fiber ratio and the volume density of mitochondria in m. vastus lateralis increased by +15% and +40%, respectively. In contrast, the untrained m. deltoideus showed an unchanged capillary per fiber ratio and a decreased mitochondrial volume density (-17%). Despite this decrease of mitochondrial volume arm-VO2max increased by +9%. It seems unlikely that the observed discrepancy can be explained by cardiovascular adaptations, since arm cranking did not fully tax the cardiovascular system (arm-VO2max/leg-VO2max: 0.74 and 0.71 before and after training, respectively). Thus neither cardiovascular adaptations nor local structural changes in the untrained muscles could explain the increased arm-VO2max. However, the enhanced capacity for lactate clearance after endurance training could be sufficient to account for the larger VO2max during arm cranking. We propose that an increased net oxidation of lactate might be responsible for the increased arm-VO2max found after bicycle endurance training.

Adult↗
PubMed1985

[Incidence of occipital ventriculomegaly in premature infants with peri-intraventricular hemorrhage].

Ventricular dilatation after periventricular/intraventricular hemorrhage (PIVH) is a more common complication than was assumed before the advent of ultrasound. In this prospective study based on 264 ultrasonic head scans, the true incidence of ventriculomegaly was investigated in two groups of preterm infants with PIVH. The major incidence of PIVH in babies with less than 34 weeks of gestation (p less than 0.05) was confirmed. Statistical analysis of the follow-up examinations showed that the degree of ventriculomegaly correlated well with the extent of the cerebral-intraventricular hemorrhage (X2 test, p less than 0.002).

Cerebral Hemorrhage↗
PubMed1985

Oxidation and metabolic effects of fructose or glucose ingested before exercise.

The aim of this study was to compare the effects of fructose (F) and glucose (G) intake before exercise on oxidation of the ingested substrate, glycogen utilization, work output, and metabolic changes. Ten trained subjects ingested F or G (1 g/kg), both of which were naturally enriched in 13C. After 1 h of rest, they exercised on an ergometer at 61% of their maximal oxygen uptake (VO2 max) for 45 min, which was immediately followed by 15 min at their maximal voluntary output. During the resting hour, blood insulin and glucose were lower (p less than 0.05) and respiratory quotient and blood lactate higher (p less than 0.01) after F. During exercise, the differences disappeared, apart from a transient but moderate (4.3 mmol/l) hypoglycemia after G compared to F. No difference between F and G was observed for uric acid, glycerol, FFA, and glucagon. Glycogen decrements in the vastus lateralis muscle were 67 +/- 9 (F) and 97 +/- 15 (G) mmol/kg, values not significantly different from each other (P greater than 0.05). The maximal voluntary work produced during the last 15 min did not differ between treatments. During the 2 h after sugar ingestion, 30 +/- 3 g of F and 26 +/- 3 g of G were oxidized to 13CO2. These findings indicate that fructose ingested before exercise was utilized at least as well as glucose, allowed a more stable glycemia, and did not modify performance.

Adult↗
PubMed1985

Endurance training in humans: aerobic capacity and structure of skeletal muscle.

The adaptation of muscle structure, power output, and mass-specific rate of maximal O2 consumption (VO2max/Mb) with endurance training on bicycle ergometers was studied for five male and five female subjects. Biopsies of vastus lateralis muscle and VO2max determinations were made at the start and end of 6 wk of training. The power output maintained on the ergometer daily for 30 min was adjusted to achieve a heart rate exceeding 85% of the maximum for two-thirds of the training session. It is proposed that the observed preferential proliferation of subsarcolemmal vs. interfibrillar mitochondria and the increase in intracellular lipid deposits are two possible mechanisms by which muscle cells adapt to an increased use of fat as a fuel. The relative increase of VO2max/Mb (14%) with training was found to be smaller by more than twofold than the relative increase in maximal maintained power (33%) and the relative change in the volume density of total mitochondria (+40%). However, the calculated VO2 required at an efficiency of 0.25 to produce the observed mass-specific increase in maximal maintained power matched the actual increase in VO2max/Mb (8.0 and 6.5 ml O2 X min-1 X kg-1, respectively). These results indicate that despite disparate relative changes the absolute change in aerobic capacity at the local level (maintained power) can account for the increase in aerobic capacity observed at the general level (VO2max).

Adipose Tissue↗
PubMed1985

Malleability of the motor system: training for maximizing power output.

The training programmes used to improve the strength and/or endurance capacities of athletes are described. Specific stimuli are either high tension in contracting myofibrils or high turnover rates in the oxidative metabolism of the muscle cell. Structural adaptations consist of the synthesis of additional myofibrillar material or increased volume density of both interfibrillar and subsarcolemmal mitochondria. Transformation of fibre types at the level of the molecular structure of myosin seems possible with high-intensity training of long duration. Functional adaptations consist of higher activities of important enzymes in either anaerobic or aerobic energy metabolism and of larger intracellular stores of the respective substrates. All adaptations are highly specific and reversible through detraining or immobilization of the muscle.

Adaptation, Physiological↗
PubMed1985

Interruption of breast-feeding versus phototherapy as treatment of hyperbilirubinemia in full-term infants.

Since 1963 there are reports in the literature about the syndrome of breast milk jaundice. The factors that may contribute to this phenomenon are still unclear. In our study the effect of interruption of breast-feeding in 25 jaundiced full-term infants was compared to the effect of phototherapy in 25 jaundiced otherwise healthy full-term infants. The results show that this treatment has the same therapeutic effect as phototherapy (p greater than 0.05) without its stressful complications and can be recommended as alternative treatment of this type of hyperbilirubinemia.

Bilirubin↗
PubMed1985

[Ergometric validation of a questionnaire on the physical activity in 2 Swiss towns].

A questionnaire concerning physical activity used in the National Research Program No. 1A (PNR 1A) was evaluated by using a physical fitness test on an ergometric bicycle. The values of maximum oxygen consumption correspond to different classes of physical activity set up according to the questionnaire (comparison of groups statistically significant). In addition, it appears that maximal oxygen consumption is in direct relation to the intensity of physical activity during leisure hours, whilst the degree of activity connected with professional or household duties is of very little importance.

Adult↗
PubMed1979

[Prevention of arteriosclerosis. Current basis].

Despite the advances in therapy, the high incidence, high mortality, and prematurity of coronary heart disease demonstrate the need for prevention. Measurement of a series of easily determined risk factors permits the early recognition of subjects at risk with remarkable reliability. However, reduction of risk factors affords protection against the illness only if they are causally connected with the disease mechanisms. The major evidence for linking atherosclerosis and its consequences with risk factors is reviewed. Particular attention is focused on serum lipids and the "lipid theory", smoking, elevated blood pressure, and physical inactivity, which are, on the basis of current knowledge, not only the most important factors but those most readily influenced by changes in daily living habits. Among the multiple risk factors mention is also made of obesity, diabetes, psychosocial stress, and hereditary predisposition. The probability of a causal relationship between risk factors and disease mechanisms justifies every effort to prevent the development of these precursors, or to treat them prophylactically if already present.

Arteriosclerosis↗
PubMed1979

Liver function in physically trained subjects: galactose elimination capacity, plasma disappearance of indocyanine green, and aminopyrine metabolism in long-distance runners.

Physical exercise and physical training are known to affect several aspects of hepatic metabolism. To assess whether adaptation to long-lasting exercise modifies microsomal drug metabolism, 8 long-distance runners were compared with a group of medical students having significantly lower maximal rates of oxygen consumption. At rest the hepatic galactose elimination capacity and the indocyanine green plasma disappearance rate used as reference methods were the same in both groups. The plasma clearance of ([14C]dimethylamine) aminopyrine and the kinetics of 14CO2 in breath did not differ either. It is concluded that adaptation to long-lasting exercise can occur without evidence for changes in hepatic galactokinase activity, liver blood flow, or microsomal metabolism of aminopyrine.

Adaptation, Physiological↗
PubMed1979

Mitochondrial volume density in human skeletal muscle following heavy resistance training.

Needle biopsies were taken from triceps brachii of 6 healthy males before and after a 6 month intensive weight training programme. The tissue was sectioned, photographed under a Philips EM200 and subjected to stereological analysis. Cross sectional fibre areas were also calculated from cryostat sections stained for ATPase activity. Morphometric analysis indicated that training resulted in a significant 26% reduction in mitochondrial volume density and a 25% reduction in the mitochondrial volume to myofibrillar volume ratio. These changes were accompanied by significant increases in fibre area for both FT (33%) and ST (27%) fibres as determined from the light microscope. There was a significant correlation between the reduction in mitochondrial volume density and the increase in FT fibre area following training (r=0.845). It was concluded that heavy resistance training leads to a dilution of the mitochondrial volume density through an increase in myofibrillar size with hypertrophy.

Adenosine Triphosphatases↗