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Biomedical subjects

J Muller

Publications and source records attributed to J Muller.

At least 199 records · Page 11Linked to original sources
PubMed1981

Relation of ADH effects to altered membrane fluidity in toad urinary bladder.

Membrane fluidity, urea permeability, and osmotic water permeability in toad urinary bladder are regularly enhanced by antidiuretic hormone (ADH). In addition, organized intramembranous particle aggregates, which correlate specifically with hormonally stimulated water permeability, are found in granular cell luminal membranes consequent to ADH stimulation. In this investigation ADH-stimulated changes in urea and osmotic water permeability and luminal membrane aggregates at room temperature (24.8 +/- 0.4 degrees C) and in the cold 10.6 +/- 0.2 degrees) were compared with corresponding changes in membrane fluidity, as assessed by n-butyramide permeability. Although a critical level of membrane fluidity is undoubtedly required, the occurrence of aggregates in the luminal membrane is independent of an accompanying hormonally induced change of membrane fluidity. ADH-stimulated osmotic water permeability in toad bladder is also independent of the coincident change in membrane fluidity, and as a process almost certainly involves membrane channels, not a solubility-diffusion process through membrane lipids. For ADH-stimulated transbladder urea movement, channels seem to be involved as well, and the change induced in membrane fluidity by ADH could be an underlying factor in their formation.

Animals↗
PubMed1981

Cribside neurosonography: real-time sonography for intracranial investigation of the neonate.

A prospective study was made of 94 real-time sonographic sector scans of 56 neonates in a 6 month period. The examinations were performed using the anterior fontanelle as an acoustic window. In 17 cases, computed tomography (CT) head scans were available for comparison. In no case did the CT and sonographic examination disagree as to the size of the lateral ventricles. Abnormalities detected by sonography include ventriculomegaly, intracerebral hematomas, a congenital glioma, and several cystic lesions. Sonographic sector scanning produces excellent, detailed images of dilated lateral and third ventricles, uses no ionizing radiation, is less expensive than CT, and can be performed in the isolette, minimizing the risk of hypoxia and hypothermia. At Methodist Hospital Graduate Medical Center, sonography has replaced CT as the initial method of investigation of ventricular size. CT plays a complementary role in the evaluation of the posterior fossa, intracranial hemorrhage, and mass lesions.

Cerebral Arteries↗
PubMed1980

Nifedipine therapy for coronary-artery spasm. Experience in 127 patients.

We report clinical experience with the coronary vasodilator nifedipine in 127 patients with symptoms of myocardial ischemia associated with electrocardiographic or angiographic evidence, or both, of coronary-artery spasm. In the majority of patients conventional antianginal therapy including nitrates and beta-adrenergic blockers failed, and in one third of the patients at least one episode of ventricular tachycardia developed during an attack of angina. Nifedipine (40 to 160 mg every 24 hours) significantly reduced the mean weekly rate of anginal attacks from 16 to two (P less than 0.001). Similar marked reductions in the nitroglycerin requirement were noted. In 63 per cent of the patients complete control of anginal attacks was achieved, and in 87 per cent the frequency of angina was reduced by at least 50 per cent. Nifedipine was generally well tolerated, with only 5 per cent of the patients requiring termination of the drug because of intolerable side effects. This experience with nifedipine suggests that it is a highly effective drug for the treatment of coronary-artery spasm and variant angina.

Adult↗
PubMed1980

A family with three recessive traits and homozygosity for a long 9qh+ chromosome segment.

We report a family in which a mentally retarded, proportionately dwarfed girl had a child from a presumably incestuous mating that had the Ellis van-Creveld syndrome, presumed autosomal recessive hydrocephalus (Dandy-Walker type), and homozygosity for an extremely long 9qh+ chromosomal marker. The mentally retarded mother had normal birth weight, unusual facial appearance, and virtual absence of secondary sexual hair; she developed severe hypoglycemia during pregnancy. Her parents were first cousins, and she may have a previously unreported autosomal recessive syndrome.

Chromosomes, Human, 6-12 and X↗
PubMed1980

Evidence that ADH-stimulated intramembrane particle aggregates are transferred from cytoplasmic to luminal membranes in toad bladder epithelial cells.

In freeze-fracture (FF) preparations of ADH-stimulated toad urinary bladder, characteristic intramembrane particle (IMP) aggregates are seen on the protoplasmic (P) face of the luminal membrane of granular cells while complementary parallel grooves are found on the exoplasmic (E) face. These IMP aggregates specifically correlate with ADH-induced changes in water permeability. Tubular cytoplasmic structures whose membranes contain IMP aggregates which look identical to the IMP aggregates in the luminal membrane have also been described in granular cells from unstimulated and ADH-stimulated bladders. The diameter of these cytoplasmic structures (0.11 +/- 0.004 micrometers) corresponds to that of tubular invaginations of the luminal membrane seen in thin sections of ADH-treated bladders (0.13 +/- 0.005 micrometers). Continuity between the membranes of these cytoplasmic structures (which are not granules) and the luminal membrane has been directly observed in favorable cross-fractures. In FF preparations of the luminal membrane, these apparent fusion events are seen as round, ice-filled invaginations (0.13 +/- 0.01 micrometer Diam), of which about half have the characteristic ADH-associated aggregates near the point of membrane fusion. They are less numerous than, but linearly related to, the number of aggregates counted in the same preparations (n = 78, r = 0.71, P less than 0.01). These observations suggest that the IMP aggregates seen in luminal membrane after ADH stimulation are transferred preformed by fusion of cytoplasmic with luminal membrane.

Animals↗
PubMed1980

Hypoxic lesions in areas of primary myelination. A distinct pattern in cerebral palsy.

The stage of regional structural and biochemical development of the central nervous system appears to be a critical factor determining the topistic distribution of 'hypoxic' lesions during the perinatal period. This report describes the brain lesions of 6 patients who suffered 'hypoxia' or ischemia during the perinatal period. 5 of these cases uniformly displayed symmetric ulegyria limited to areas of primary myelination, white matter damage subjacent to the cortical lesions, and status marmoratus of the basal ganglia and thalami. Areas of association which myelinate later in the postnatal period were basically normal. It is postulated that the damaged areas, at the moment of 'hypoxic' insult, had higher respiratory rates than the undamaged areas and, therefore, were more susceptible to oxygen deprivation.

Adult↗
PubMed1979

Nifedipine in the treatment of Prinzmetal's (variant) angina.

The clinical response to therapy with the calcium-blocking agent nifedipine was assessed in 12 patients with variant angina pectoris who were 44 to 67 years old. Five patients had vasospasm of the left anterior descending coronary artery, and seven had spasm of a dominant right coronary artery. Before nifedipine therapy, the frequency of anginal attacks per 24 hour period ranged from 1 to 12, with ventricular tachycardia accompanying ischemic episodes in 7 of 12 patients and high grade atrioventricular block occurring in 2 patients. After therapy with nifedipine, 11 of 12 patients had initial relief of symptoms, and 7 of the 11 had long-term relief. Withdrawal of nifedipine led to recurrence of angina on six occasions in four patients. Provocative testing in the cardiac catheterization laboratory by means of the cold pressor test in one patient and ergonovine maleate in another before and after nifedipine administration showed that this agent can block both alpha adrenergic- and regonovine-induced vasospasm. Nifedipine may have a significant role in the therapy of angina caused by coronary spasm.

Adult↗
PubMed1979

Temperature dependence of ADH-induced water flow and intramembranous particle aggregates in toad bladder.

Antidiuretic hormone (ADH)-induced luminal intramembranous particle aggregates and hormonally stimulated water flow in toad urinary bladder are reduced simultaneously with a reduction in temperature. When water movement is factored by the aggregation response, the apparent activation energy for this process decreases from 12.1 +/- 1.6 to 3.0 +/- 2.3 kilocalories per mole. The data are consistent with the view that the particle aggregates contain sites for transmembrane water movement and that these sites behave as pores.

Animals↗
PubMed1979

Familial islet cell tumors in Von Hippel-Lindau's disease.

Von Hippel-Lindau's Disease is an hereditary disorder characterized by the development of hemangioblastomas of the cerebellum and retina and a variety of cystic and neoplastic lesions of other organs such as renal cell carcinoma and pheochromocytoma. In a single generation of a family with Von Hippel-Lindau's disease, all four siblings developed lesions classically associated with the complex. Additionally, two of the four developed islet cell tumors of the pancreas, one in one patient and five in the other. While a familial incidence of islet cell tumors is known in multiple endocrine adenomatosis, type I and Zollinger-Ellison syndrome, such a familial occurrence has been heretofore unrecorded in the Von Hippel-Lindau complex.

Adenoma, Islet Cell↗
PubMed1979

Optic chiasmatic glioma in children.

We reviewed the records of 29 patients with optic nerve or chiasm glioma, or both, seen from 1955 to 1966. Sixteen patients were girls and 13 were boys. At the time of diagnosis, 14 patients were less than 2 years old. Optic atrophy was the most frequently seen physical finding, present in 26 of 29 patients. Twelve patients had diencephalic syndrome (41%). Proptosis was seen in eight. Eleven patients (38%) had associated neurofibromatosis. Pneumoencaphalogram was done on 26 patients and was abnormal in 23. The diagnosis was confirmed at surgery in 27 patients. All tumors were astrocytomas. Eighteen patients underwent radiotherapy. Surgery and radiotherapy were used as treatment for optic-chiasmatic glioma with diencephalic syndrome.

Age Factors↗
PubMed1979

Possible roles for microtubules and microfilaments in ADH action on toad urinary bladder.

Intramembranous particle aggregates in the luminal membrane of toad bladder granular cells after vasopressin stimulation have been found to correlate closely and specifically with induced alterations of water permeability. Roles for microtubules and microfilaments in mediating the latter response have been proposed on the basis of studies involving colchicine and cytochalasin B, respectively. In the present investigation the effects of these agents on both initiating and sustaining vasopressin-induced osmotic water flow and the particle aggregation phenomenon were studied. The results indicate that during initiation the aggregation and water flow responses to vasopressin are each colchicine- and cytochalasin B-sensitive and that these sensitivities can be wholly additive. However, after full vasopressin stimulation is established, the same responses demonstrate sensitivity only to cytochalasin B, not to colchicine. The findings, therefore, suggest that microtubules and microfilaments may be independently necessary for the initiation of the aggregation and water flow responses to vasopressin, and that microfilaments, but not microtubules, are required for their maintenance.

Animals↗
PubMed1978

Infantile and juvenile cerebral aneurysms.

Primary cerebral aneurysms (i.e., of noninflammatory or nontraumatic etiology) are rare in the pediatric age group. Twelve cases of intracranial aneurysms occurring in infancy, childhood, and adolescence are presented and discussed. These aneurysms are different from the classic so-called berry aneurysms seen in adults. This group can be said to constitute a separate and novel entity.

Adolescent↗
PubMed1978

Morphologic abnormalities in a case of malignant hyperthermia.

An 8-year-old boy underwent general anesthesia and experienced an episode of malignant hyperthemia, characterized by elevated temperature, cardiac arrhythmias, markedly elevated serum enzymes (SGOT, LDH, and CPK), proteinuria, and hemoglobinuria. Sixty-six days after anesthesia a skeletal muscle biopsy was obtained for examination by electron and light microscopy, which showed skeletal muscle cells with abnormally numerous mitochondria, enlarged, and variable in shape. Some contained abnormal cristae. There were more lysosomes than normal, and lipofuscin was increased in quantity. Myelin-like bodies were also present. Previous reports of muscle abnormalities are reviewed and compared with the data in this case.

Child↗
PubMed1978

[Torsion of Riedel's lobe. Two cases (author's transl)].

The authors report two cases of torsion of Riedel's lobe. The first case resembled acute cholecystitis. Resection was followed by a cure. The second case presented in the form of a complicated abdomino-pelvic tumor. Its removal did not prevent a fatal issue due to fibrinolysis probably related to advanced ischemic infarction of Riedel's lobe of the liver. It seems that these complications are exceptional.

Abdominal Neoplasms↗
PubMed1977

Congenital dysplasia of C2--6.

Neural arch dysplasia of the cervical vertebrae is a rare occurrence. The authors present a case with dysplasia of cervical bodies and posterior arch elements at multiple levels. The embryogenesis of these anomalies is discussed.

Adolescent↗