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Biomedical subjects

W Berger

Publications and source records attributed to W Berger.

At least 235 records · Page 13Linked to original sources
PubMed1983

[Oral antidiabetic agents: recent aspects].

Sulfonylureas are the most potent and widely used oral antidiabetic agents. Despite the finding of possible side effects in a large multicenter trial (UGDP Study) demonstrating increased cardiovascular mortality during tolbutamide therapy, prescription of sulfonylureas has not declined in view of the inconclusive results of the study. In addition, new aspects of their mode of action have been discovered. Sulfonylureas may enhance insulin sensitivity of peripheral tissues, particularly by raising the decreased number of insulin receptors in type II diabetics. While this extrapancreatic effect appears to be quantitatively important, it is only present when insulin secretion is simultaneously stimulated. Insulin release is enhanced due to an increase in the sensitivity of the B-cell to glucose challenge. There is evidence to suggest that the extrapancreatic effect of sulfonylureas is secondary to their pancreatic effect. Pointers in the same direction emerged from our own results in a study on the influence of sulfonylureas added to insulin therapy on insulin sensitivity in type I diabetics. Sulfonylureas failed to increase insulin sensitivity and insulin requirements in these patients. The first generation compounds of sulfonylureas are associated with more side effects and drug interactions than the second generation preparations. However, the latter are more frequently associated with hypoglycemia since they are more potent and have a prolonged duration of action. Biguanides have almost fallen into disuse as therapeutic agents due to the potentially lethal complication of lactic acidosis. Only metformin may still be indicated in certain cases. Inhibitors of intestinal amylase and glucosidase represent a new therapeutic principle in diabetes therapy whose aim is to reduce postprandial hyperglycemia. Their value as therapeutic agents is not yet clearly established.

Administration, Oral↗
PubMed1983

Normal and impaired regulation of muscle stiffness in gait: a new hypothesis about muscle hypertonia.

The activation of leg muscles was analyzed in respect to ankle joint movement and the changes in tension produced by the triceps surae muscle during slow gait in spastic adults and children with cerebral palsy. In normal subjects the increase in tension of the triceps surae in the stance phase of gait is mainly due to an increase in gastrocnemius and soleus EMG. In spastic patients the abnormally high tension development in triceps surae is due more to passive muscle stretch, for the reciprocally organized leg muscle EMG is reduced. It is concluded that the leg extensor muscles in spastic patients exhibit a pseudostretch-reflex behavior due to their mechanical properties, and that this is mainly responsible for muscle hypertonia. The coactivation of the leg muscles seen in children with cerebral palsy, which also is seen in the stepping of the newborn, suggests impaired maturation of the neuronal locomotor pattern.

Adult↗
PubMed1982

Association of specific immune response to pork and beef insulin with certain HLA-DR antigens in type 1 diabetes.

To test the association of HLA-DR antigens with high-responder and low-responder status to either beef or pork insulin, insulin antibodies in diabetic sera were separated into those with average low and those with average high affinity and their insulin-binding capacities for each insulin determined. Significantly less binding of pork insulin by the high affinity antibodies occurred in the group of patients with DR3 antigens compared with those with DR4 antigens (p less than 0.01) and DR3/4 antigens (p less than 0.01). The difference in the binding capacity of beef insulin by the high affinity antibodies between the groups with DR3 and DR4 antigens was less pronounced but still significant. The high-responder status of DR3/4 antigens to pork insulin suggests that the gene or genes associated with HLA-DR4, and responsible for a high response to pork insulin, are dominant to genes associated with HLA-DR3 and a low response. If extended to human insulin and different HLA-DR and HLA-B antigen patterns, these finding should help in the therapeutic selection of the appropriate insulin and thus reduce the induction of an anti-insulin response in patients with diabetes.

Animals↗
PubMed1982

[Diabetes mellitus and pregnancy. Case contributions on the state of therapy].

Modern means for monitoring and treatment of pregnant diabetics are demonstrated in 6 cases. To quantify the degree of diabetic control regular control of blood glucose profiles and determination of glycosylated hemoglobin (hemoglobin A1 or A1c) are required. Blood glucose measurements can be carried out by self-monitoring or by drawing blood samples and bringing them to the laboratory for analysis. To avoid fetal malformations and to protect the mother, normoglycemia should be obtained. If this goal cannot be reached by conventional insulin therapy with several single injections a day, the authors use a portable infusion pump for continuous subcutaneous infusion. This treatment is of particular importance in high risk patients with retinopathy and nephropathy. For fetal monitoring cardiotocography was the main method. Since the lecithin/sphingomyelin ratio of amniotic fluid is not always a reliable indicator of fetal lung maturity in diabetic pregnancies, the amniotic lecithin concentration is also measured. Estriol and HPL as indices of feto-placental function can be misleadingly high in plasma (or low in urine) in patients with impaired renal function. Optimal treatment of pregnant diabetics requires close collaboration with the obstetrician and the neonatal pediatrician.

Adult↗
PubMed1982

Spinal coordination of bilateral leg muscle activity during balancing.

While subjects were standing and balancing on two separate seesaws, the EMG of the leg muscles and the positions of the two seesaws were recorded. The spontaneous balancing movements with predominant oscillations of 4-5 Hz, and the accompanying bursts of EMG activity in the leg muscles occurred quite symmetrically on the two sides. After a displacement, induced either by stimulating the tibial nerves, or by a brisk anterior tilt of one seesaw, the EMG responses of the tibialis anterior muscles started with the same latency (about 50 ms) on both sides, and with similar amplitudes, even when only one side was displaced. It is concluded that this symmetrical leg muscle activation is mediated by a spinal coordinating mechanism the function of which depends on the actual motor task.

Electromyography↗
PubMed1982

Pathophysiology of gait in children with cerebral palsy.

The surface electromyogram (EMG) of leg muscles was recorded together with the changes of the angle at the ankle joint during slow gait in 10 normal children and 10 with cerebral palsy. The characteristic pattern of muscle activity recorded from the spastic legs mainly consisted of a co-activation of antagonistic leg muscles during the stance phase of a gait cycle and a general reduction in amplitude of EMG activity. The tension of the Achilles tendon, measured in 2 hemiparetic children during gait, increased much more steeply in the spastic leg than in the normal one at the beginning of the stance phase, when the electrically almost silent triceps surae was stretched. It is suggested that muscle hypertonia during gait in spastic children is mainly due to changed muscle fibre mechanical properties, as recently discussed also for spastic adults. While in the latter the reciprocal EMG activity of antagonistic leg muscles was preserved it is proposed that muscle co-activation recorded in spastic children is due to an impaired maturation of the locomotor pattern with an early neuronal adaptation to altered muscle fibre mechanical characteristics.

Adolescent↗
PubMed1981

Autonomic disturbances in relation to sensorimotor peripheral neuropathy in diabetes mellitus.

Thirty patients with diabetes mellitus were investigated. Twenty-seven had clinical signs of a symmetrical sensory or sensorimotor polyneuropathy. Features of autonomic dysfunction were found in 17 patients. Nerve conduction was studied in the femoral, deep peroneal, saphenous, sural and sensory and motor fibres of the posterior tibial nerves. The postural heart rate response was tested in all of the 30 patients. There was only a weak correlation between autonomic disturbances and sensorimotor polyneuropathy, based either on clinical or on electrophysiological results. Thus a multifactorial causation is suspected.

Adult↗
PubMed1981

Electrophysiological studies of gait in spasticity and rigidity. Evidence that altered mechanical properties of muscle contribute to hypertonia.

The surface electromyogram (EMG) of mm. tibialis anterior and triceps surae was recorded in 10 patients with spasticity, 10 patients with rigidity and 20 normal subjects and correlated with the changes in ankle joint angle during the different phases of the gait cycle. While the strength and timing of EMG activity recorded from triceps surae during the stance phase of gait did not differ from that of normal subjects, the EMG of tibialis anterior was significantly stronger during the swing phase in both groups of patients. Although the reciprocally organized innervation pattern of the leg muscles was preserved, spastic patients could hardly lift up the affected foot during the swing phase despite the enhanced activity of tibialis anterior. There was no coactivation of the calf muscles during the hyperactivity of tibialis anterior. Therefore, no electrophysiological explanation could be found for the increased muscle tone in either group of patients. The possibilities of reduced force development by the muscle fibres of tibialis anterior or of some mechanical obstruction in the ankle joint were largely excluded as alternative explanations underlying the impeded elevation of the foot. We suppose that in both diseases the muscle fibres undergo changes which are responsible for increased muscle tone in spasticity and rigidity. The pathophysiological mechanism of these changes remains unknown.

Adolescent↗
PubMed1981

Sensory and motor parameters in leg nerves of diabetics: intercorrelations and relationships to clinical symptoms.

Nerve conduction was studied in various sensory and motor leg nerves in diabetics. Distal nerves were more affected than proximal ones. There was a poor correlation between neurographic results and the severity of clinical symptoms. No relationship was found between the degree of alteration of the individual neurographic parameter and the duration of diabetes and the fasting blood glucose level.

Action Potentials↗