Biomedical subjects

L Ludwig

Publications and source records attributed to L Ludwig.

44 records · Page 3Linked to original sources

PubMed1981

Impaired beta-adrenergic stimulation in the uninvolved ventricle post-acute myocardial infarction: reversible defect due to excessive circulating catecholamine-induced decline in number and affinity of beta-receptors.

Left ventricular infarction (AMI) was produced in experimental animals and the contractile response to isoproterenol was tested in the isolated perfused heart preparation. Adenylate cyclase activity, phosphodiesterase activity, and beta-receptor binding characteristics were determined in a sarcolemmal preparation of the right ventricle of the same hearts. Three days post-AMI the dose-response curve for isoproterenol of right ventricular dP/dtmax was significantly depressed, while the inotropic effect of histamine was not impaired. Stimulation of adenylate cyclase activity by isoproterenol was reduced by 70% in the membrane preparation, whereas histamine and NaF stimulation rates were unaltered; phosphodiesterase activity was unchanged. In contrast, beta-receptor binding studies with [3H]-DHA1 indicated 74% loss and 10 times lowered affinity (KD) of the remaining beta-receptors, while specific [3H]-QNB1 binding was unchanged. All of the above alterations were prevented by pretreatment with reserpine or metoprolol. It is concluded that these abnormalities in the nonischemic surviving myocardium post-AMI are the result of specific reversible damage of sarcolemmal beta-receptors due to excessive levels of circulating catecholamines.

Adenylyl Cyclases↗

PubMed1981

[Peptic ulceration of the oesophagus. Report of 18 cases].

From 1968 to 1979 881 patients suffering from peptic ulcerations were seen at the Surgical Dept. of the "Medizinische Akademie - Dresden". In a percentage of 2.04 these ulcers were located in the oesophagus (n = 18) near the cardia. Due to the high rate of complications following conservative treatment the authors recommend resection of the oesophageal ulcers and oesophago-gastrostomy. After operation no gastro-oesophageal reflux could be observed.

Adult↗

PubMed1979

Exploration and play in retarded and nonretarded preschool children: effects of object complexity and age.

Three-dimensional random polygon objects ranging in complexity between 4 and 40 turns were presented to 12, 30-month-old and 12, 42-month-old moderately retarded and nonretarded children. Time spent in exploration and in play was measured over three successive exposure-time blocks. Exploration time for the combined sample of retarded and nonretarded younger children did not vary with object complexity. The older retarded children explored objects of low complexity more than did either the combined sample of younger children or the older nonretarded children. Nonretarded older children explored complex objects more than did the combined sample of younger children. Exploration time decreased linearly with exposure-time blocks. Play time increased linearly with successive exposure-time blocks and decreased linearly with increasing complexity.

Age Factors↗

PubMed1977

[Basal cell adenomas of the salivary glands. Analysis of 7 cases and review of the literature. Comparative study with cylindromas].

Basal cell adenomas, of which 7 cases are reported here together with 63 others collected in the literature, are benign tumours of the salivary glands, preferentially localised in the parotid and in the upper lip. Mobile, non-ulcerated and painless, these nodules with an average diameter of 2 cm are well circumscribed, fleshy or cystic. Their morphology is characterised by the proliferation of uniform, small cells, with scarcely visible cytoplasm, arranged in layers, cords and canals, which may be ectasic or cystic. Peripheral elements, individualising these different structures, are arranged in palissades and are regularly surrounded by a basal membrane. The histological analogies between basal cell adenomas and cylindromas merely reflect their ultrastructural similarities, cellular as well as architectural. These two neoplasms may be distinguished on the basis of two essential morphological criteria:--basal cell adenomas are well circumscribed, whilst cylindromas are invasive;--the cells in adenomas are closely juxtaposed, endowing the various structures of these tumours with a dense appearance, whilst cylindroma cells are generally separated by clear spaces corresponding to extreme development of the intercellular spaces.

Adenoma↗

PubMedDate not supplied

Relief of posttraumatic headache by intravenous chlorpromazine.

We report the case of an 18-year-old male with a vascular-type headache occurring 3 days after a minor closed-head injury. The headache resolved completely, without recurrence, with a single dose of intravenous chlorpromazine. This case and the few others reported in the literature illustrate that the response of a headache to antimigraine therapy cannot be relied upon to diagnose or confirm a diagnosis of migraine headache, or to rule out other intracranial pathology.

Adolescent↗

PubMedDate not supplied

Effect of point of care testing on length of stay in an adult emergency department.

Devices are now available that are practical for point of care testing (PCT) in hospital settings. Previous studies in clinical settings, however, have failed to demonstrate a reduction in patients' length of stay (LOS) associated with the use of PCT. This randomized controlled study compared PCT with central laboratory testing in a hospital Emergency Department to assess the difference in patients' LOS. Patients randomized to PCT (n = 93) had a median stay of 3 h, 28 min (interquartile range [IR] 2:28 to 5:30), while those allocated to the central laboratory (n = 87) had a median stay of 4 h, 22 min (IR 3:04 to 5:47). The median stay associated with PCT was significantly shorter. Among patients who were destined to be discharged home, there was also a significantly shorter stay, but not among those who were destined to be admitted. It was concluded that the use of PCT can achieve significant time savings in an Emergency Department.

Adolescent↗

PubMedDate not supplied

Effective stimulation of cardiac contractility and myocardial metabolism by impromidine and dimaprit--two new H2-agonistic compounds--in the surviving, catecholamine-insensitive myocardium after coronary occlusion.

Left ventricular infarctions were produced in guinea pigs, and the contractile response to beta-adrenergic and H2-histaminergic stimulation was tested in isolated perfused heart preparations. Adenylate cyclase activity and binding characteristics of sarcolemmal beta 1-, H2-, and muscarinic cholinergic receptors were determined in sarcolemmal membrane preparations of the uninvolved right ventricle of the same hearts. Three days after infarction, the positive inotropic effects of isoproterenol (2.8 X 10(-9) mol/L) and tyramine (5.5 X 10(-5) mol/L) were nearly abolished, while the inotropic effects of impromidine (4.6 X 10(-7) mol/L) and dimaprit (8.5 X 10(-6) mol/L) were not impaired. Stimulation rates of cardiac adenylate cyclase activity by isoproterenol were markedly reduced (-90%) whereas impromidine, dimaprit, and NaF revealed stimulation rates equivalent to the sham-operated control group. beta-Receptor binding studies with [3H]dihydroalprenol revealed 90% loss and nearly 10 times lowered affinity (KD) of the remaining receptors, while specific binding of [3H]tiotidine and [3H]quinuclidinyl-benzylate was unchanged in the same preparations. All of the above alterations could be prevented to a similar extent by treatment with different beta-blocking agents, but differences between the drugs were seen with respect to survival rates and reduction of infarct size. In agreement with previous findings, we conclude that the observed alterations in the nonischemic surviving myocardium are the result of specific damage of sarcolemmal beta-receptors due to excessive exposure to increased catecholamines after infarction. The stimulation of the uninvolved H2-receptors may be of therapeutic value.

Adenylyl Cyclases↗

PubMedDate not supplied

Effects of the H2-receptor agonist impromidine in human myocardium from patients with heart failure due to mitral and aortic valve disease.

We determined stimulation rates of cardiac adenylate cyclase activity by isoproterenol and impromidine in particulate sarcolemmal membrane preparations from human papillary muscles resected during open heart replacement of mitral and aortic valves. In addition, specific receptor binding studies with [3H]dihydroalprenolol [( 3H]DHA) to cardiac beta-receptors and [3H]tiotidine [( 3H]TIOT) to cardiac H2-receptors were carried out in the same preparations. Compared with the response in patients with pure mitral valve stenosis, the response of cardiac adenylate cyclase activity to isoproterenol showed a marked decrease (-90%) in patients with combined mitral and aortic valve disease, corresponding to the severity of degree of insufficiency at both valves. Similar changes were observed in receptor binding studies with [3H]DHA, in which the reduction of beta-receptor density was of the same order of magnitude. In contrast, stimulation of the enzyme by impromidine and binding capacity of [3H]TIOT to cardiac H2-receptors were found to be unaltered in the same membrane preparations of all 16 patients. We conclude that treatment with H2-agonists may be a new therapeutic approach to congestive heart failure, especially in patients not responding to beta-adrenoceptor stimulation with beta-sympathomimetic drugs.

Adenylyl Cyclases↗