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Biomedical subjects

D Schmidt

Publications and source records attributed to D Schmidt.

At least 487 records · Page 27Linked to original sources
PubMed1985

Interpeak intervals of auditory brainstem response, interaural differences in normal-hearing subjects and patients with sensorineural hearing loss.

ABR recordings were made on 31 normal-hearing subjects and 253 patients with sensorineural hearing loss (86 patients with unilateral hearing loss, 61 patients with asymmetrical hearing loss, 34 patients with symmetrical hearing loss, 55 patients with noise-induced hearing loss and 17 patients in the late chronic stage of Menière's disease). In the patient group with unilateral hearing loss, the mean interpeak interval (IPI) I-V was significantly shorter than in normal-hearing subjects. The interaural IPI differences provide a sharp criterion for early detection of acoustic neuroma. The calculation of the 95%-limits (means + 1.96 SD) showed that in patients with normal hearing or with unilateral or symmetrical hearing loss an interaural difference in the IPII-V greater than 0.2 ms has to be considered as an indication of a neuroma or any other brainstem abnormality. In patients with asymmetrical or with noise-induced hearing loss, the limit is 0.3 ms. In contrast to the frequently recommended interaural wave V latency difference criterion, the interaural IPI difference criterion requires no correction for audiogram differences.

Brain Stem↗
PubMed1985

[Isolation of monocytes by adherence to gelatin-layered surfaces].

The method for purification of monocytes using adherence to gelatin coated glass surfaces described by Chien et al. was optimized by drastic shortening the incubation time and modifying the culture media. After one adherence step we obtained monocytes with a purity of 73-78% and a recovery of 53%. Thiol-protein-disulfide-oxidoreductase (TPO), a new enzyme marker of monocytes, was found to be also valid for monocytes obtained by adherence methods. Comparing the number of TPO-containing monocytes with other markers (alpha-naphthylacetate esterase, peroxidase, phagocytosis of latex particles, acridine orange fluorescence, antigens detected by the monoclonal BL-M/G antibody) almost identical values were found.

Acridine Orange↗
PubMed1985

[Malignancy grading of glial tumors. I. Astrocytomas].

A total of 91 fibrillar, protoplasmic and gemistocytic astrocytomas, 56 pilocytic astrocytomas and 70 glioblastomas, surgically obtained from 1973 to 1979, were evaluated. A four-grade malignancy system was applied to the astrocytomas. The grading criteria for the astrocytomas included quantitative cell density, cellular and nuclear polymorphism, mitotic activity, proliferative changes in the vascular elements and degree of necrosis. Using these criteria it was possible to distinguish four grades. Astrocytoma grades 1 and 2 correspond to the rubric "low-grade astrocytoma" in the English nomenclature, grades 3 and 4 to "high-grade astrocytoma". From the 91 fibrillar, protoplasmic and gemistocytic astrocytomas there were 12, 29, 31 and 19 tumors in grades 1 to 4 respectively. The corresponding distribution for the 56 pilocytic astrocytomas was 20, 29, 6, 1. Median survival for the fibrillar, protoplasmic and gemistocytic group for malignancy grades 1-4 were 43.8, 33.5, 8.4 and 5.6 months respectively. The corresponding figures for the pilocytic astrocytomas grades 1-3 were greater than 66, greater than 69, and 20.0 months.

Adult↗
PubMed1985

[Effect of drugs on granulocyte motility].

The in-vitro influence of drugs on the chemokinesis and chemotaxis of neutrophils was investigated in order to prevent additional drug-induced motility impairment of cells in cases of already existing host defense disorders and for an eventual specific treatment of motility defects. Granulocyte motility is unimpaired by penicillin, ampicillin, carbenicillin, streptomycin, nystatin, and cyclophosphamide. The chemokinesis and chemotaxis of neutrophils are inhibited by erythromycin, oxytetracycline, doxycycline, chloramphenicol, hydrocortisone, g-strophanthin, digoxin, and digitoxin and in higher concentrations also by sulfonamides, gentamycin, prednisolone, methylprednisolone, dexamethasone, and phenylbutazone. Chemotaxis is selectively or rather more inhibited than chemokinesis by amphotericin B, griseofulvin, vinblastine++, trifluoperazine, and promethazine. Granulocyte motility is, however, stimulated by ascorbic acid, potassium thiocyanate, levamisole, lithium, and metofenazate.

Anthelmintics↗
PubMed1985

Evaluation of epileptic dogs as an animal model of human epilepsy.

In 126 epileptic dogs with spontaneously recurring generalized tonic-clonic (grand mal) seizures, epidemiological aspects and the efficacy of chronic oral treatment with common antiepileptic drugs were studied. Furthermore, the pharmacokinetics of antiepileptic drugs in dogs was compared with the values known for man. As in man, idiopathic epilepsy appeared to be more common than symptomatic epilepsy in dogs. There was a preponderance of male vs. female animals. When the breeds of the epileptic dogs were compared to the distribution of breeds in the hospital population, breed-related differences in the prevalence of epilepsy were found. The highest prevalence was seen in Cocker spaniels, Miniature schnauzers, Collies and Bassets. The total prevalence of dogs with epilepsy was 0.55%. Comparison of pharmacokinetics of antiepileptic drugs showed that some drugs were suited for maintenance therapy in dogs (primidone, phenobarbital, ethosuximide, trimethadione) whereas others appeared not to be ideally suited because of their short half-lives (phenytoin, carbamazepine, valproic acid, diazepam, clonazepam, nitrazepam). This was confirmed by the evaluation of antiepileptic drug efficacy in epileptic dogs. 46 dogs were treated with primidone at daily doses of 14-104 mg/kg for 6-60 months. During medication with primidone, effective plasma levels of its metabolite phenobarbital could be maintained. Complete control of seizures or a reduction of seizure frequency by at least 75% was achieved in 39% of the dogs at phenobarbital concentrations of 5-49 micrograms/ml. Similar figures were obtained during chronic treatment with phenobarbital at daily doses of 2.5-13 mg/kg.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1984

Increased concentrations of a transferrin variant after alcohol abuse.

Isoelectric focusing in agarose gel has been used for separation of different molecular forms of transferrin (Tf) in sera and plasma from alcoholics and controls. One special form of transferrin with isoelectric point 5.7 (= Tf5.7) was quantified by using zone immunoelectrophoresis assay (ZIA). This method was also used for quantification of total transferrin (Tftot). Significant differences in the ratio Tf5.7/Tftot between the groups were obtained and the diagnostic sensitivities, specificities and predictive values of positive tests were 100, 97, 93.8%, respectively. Thus the results showed that this principle seems to be much better for detection of alcoholic abuse than currently used assays as gamma-glutamyltransferase, etc. Samples taken on days following hospitalization showed that the Tf5.7 values decreased over a two-week period of abstinence. Possible explanations for the abnormal quotient after ethanol abuse are discussed.

Adult↗
PubMed1984

Progabide as an add-on drug for epilepsy refractory to high dose antiepileptic drug therapy.

In a double-blind cross-over add-on trial an average daily dose of 2100 mg progabide or placebo were given for 3 months each as adjunctive therapy to 11 patients with intractable complex partial seizures uncontrolled by a high-dose regimen of either carbamazepine, phenobarbital, phenytoin or primidone. A reduction or an increase in seizure frequency by more than 50% was seen in one patient each. Mild transient sedative side effects were observed in two patients. The plasma concentrations of the concomitant antiepileptic drugs remained unchanged. Progabide appears to be as effective as primary antiepileptic drug for adjunctive therapy in partial epilepsy refractory to previous high-dose therapy. Progabide does not seem to be the drug urgently needed for failures of standard therapy despite its few side effects.

Adult↗
PubMed1984

Light- and electron-microscopic studies in congenital pseudarthrosis.

This study presents the results of light- and electron-microscopic and enzyme histochemical investigations in ten cases of congenital pseudarthrosis of the lower limb. At the time of surgery, six of the ten patients had not been operated on previously. The characteristic histological feature of the "sclerotic type" of congenital pseudarthrosis was a marked fibromatous reaction consisting of cellular connective tissue. The constituent cells were arranged in bundles and had elongated nuclei. The number of nuclei per visual field was considerably higher in pathological specimens than in specimens from the uninvolved leg. In places, the histological appearance resembled somewhat that of palmar fibromatosis (Dupuytren's disease). Destruction and absorption of bone were always found. Electron-microscopic analysis showed that a large number of the cells represented myofibroblasts. These findings were supported by the positive reaction of the cells for the enzyme diaminopeptidase IV, a marker enzyme for myofibroblasts [30]. As yet it is not possible to decide whether the constriction of the pseudarthritic bone is caused by a thickened myofibroblast-containing periosteum [40] or by the aggressive osteolytic component of the fibromatosis [12, 19, 41]. Furthermore, the relationship of congenital pseudarthrosis to fibrous dysplasia of bone is still unknown. Obviously, there are histological similarities between the two diseases, including the presence of osteolytic fibrous tissue in the medullary cavity and C-shaped bone trabeculae. However, the pattern of bone involvement and prognosis are different. Irrespective of the type of congenital pseudarthrosis, focal angiomatous hyperplasia was noted in some cases. This proliferation of blood vessels is most likely a reactive change.(ABSTRACT TRUNCATED AT 250 WORDS)

Bone and Bones↗
PubMed1984

Influence of environmental conditions on exocrine pancreatic response to intravenous injection of ethanol or 2-deoxyglucose in the dog.

When dogs have free access to the outside, an intravenous injection of ethanol depresses secretin-stimulated exocrine pancreatic secretion by a vagally mediated mechanism. This was shown in two separate series of six and seven dogs each. When dogs were kept in air-conditioned windowless kennels, the response to a meal was unchanged but the response to ethanol was reversed to stimulation. In four dogs, ethanol 1 g/kg was given during a secretin infusion. Three months after changing from open to closed kennels the inhibition (-86% for protein output) was still present, but after 6 months ethanol produced a stimulation (+62%) of pancreatic secretion. This increase was abolished, but not reversed, by keeping the animals outside during the day for four weeks, whereas after three months there was a partial restoration of the inhibitory effect (-39%). In contrast, changing from an open to a closed kennel changed the initial response to 2-deoxy-D-glucose (2-DG), 100 mg/kg, from stimulation to inhibition. These results suggest that environmental conditions affect the cranial regulation of pancreatic secretion.

Animals↗
PubMed1984

Cellular congenital mesoblastic nephroma in a newborn.

Typical nephroblastoma (Wilms'tumor) is uncommon within the first 6 months of life. Renal tumors most commonly found in this age constitute of two groups which have a better and worse prognosis, respectively, than typical nephroblastomas. The group of tumors with a better prognosis encompasses congenital mesoblastic nephroma (CMN), fetal rhabdomyomatous nephroblastoma and cystic, partially differentiated nephroblastoma. The group of tumors with a worse prognosis consists of rhabdoid tumor of the kidney and bone metastasizing renal tumor (clear cell sarcoma) of childhood. Adequate therapy for these two neoplasms has as yet to be developed. Among the low-grade malignant tumors congenital mesoblastic nephroma can be successfully treated with simple nephrectomy. There, are however, variants of CMN which may differ in clinical behavior from the typical form of CMN. These variants include the cellular CMN2 and, possibly, the malignant mesenchymal nephroma of infancy. A case of cellular congenital mesoblastic nephroma is presented here. Its clinical and pathologic features are discussed.

Female↗
PubMed1984

Monitoring of gamma-aminobutyric acid in human cerebrospinal fluid: downward revision of previous control values.

gamma-Aminobutyric acid (GABA) levels were measured by a radioreceptor assay in cerebrospinal fluid (CSF) specimens from two groups of subjects, one without evidence of neurological or psychiatric disease and one with a variety of neurological disorders for which GABA involvement is not known. Mean GABA concentrations in CSF for the two groups were 117 +/- 10 and 127 +/- 7.4 pmol/ml (means +/- SE for 17 and 41 individuals, respectively). These values were about half of most previously reported mean CSF GABA control values, a fact which may be attributed, at least in part, to a reduction of artifactual increase in GABA levels during sampling, storing, and thawing of CSF samples and GABA analysis. Age and sex had no significant influence on CSF GABA concentration.

Adult↗
PubMed1984

Prognosis of chronic epilepsy with complex partial seizures.

Clinical features associated with a successful or unsuccessful response to high dose antiepileptic drug therapy were evaluated prospectively in 82 patients with chronic complex partial seizures. Complete seizure control was observed during high dose drug therapy in 18 patients at plasma concentrations of either 9-35 micrograms/ml phenytoin, 32 and 40 micrograms/ml phenobarbitone, 8 micrograms/ml carbamazepine, or a combination of 25 micrograms/ml phenobarbitone and 4 micrograms/ml carbamazepine. Patients who became free of seizures had a markedly lower number of three seizures (range: 1-29) in the year before the high dose treatment as compared to 40 seizures (range: 3-328) in patients with an increased or unchanged seizure frequency (p less than 0.0001). Complex partial seizures without automatism were found only in patients with complete seizure control (22%). Patients whose seizures remained uncontrolled more frequently gave a history of severe depression or psychotic episodes, clusters of complex partial seizures, two or more seizures per day, and an aura preceding the attack. The results suggest that taking a careful history will uncover clinical features associated with a successful or unsuccessful response to high dose antiepileptic drug therapy in an epileptic out-patient with chronic complex partial seizures.

Anticonvulsants↗
PubMed1984

Therapeutic plasma levels of phenytoin, phenobarbital, and carbamazepine: individual variation in relation to seizure frequency and type.

The range and clinical features that influence the individual variation of the therapeutic plasma concentration of phenytoin, phenobarbital, and carbamazepine were studied in 84 epileptic patients on single-drug therapy. Complete cessation of seizures was observed at plasma concentrations of 17.9 (3 to 50) micrograms/ml phenytoin, 24.5 (3 to 43) micrograms/ml phenobarbital, and 6.5 (4.8 to 9.7) micrograms/ml carbamazepine. Fifty-one percent of the 53 patients receiving phenytoin were completely controlled at either below or above the 10 to 20 micrograms/ml range, suggesting that individual dosage adjustment is preferably based on clinical judgment rather than numerical limits of published therapeutic ranges. Fifty patients with therapeutic plasma concentrations of or above 15 micrograms/ml phenytoin, 25 micrograms/ml plasma concentrations of or above 15 micrograms/ml phenytoin, 25 micrograms/ml phenobarbital, or 6 micrograms/ml carbamazepine more often had partial epilepsies, complex partial seizures and, most markedly, a higher number of seizures in the first year of epilepsy and during the year prior to the present drug therapy, when compared with 34 patients with lower therapeutic plasma concentrations. The variation in therapeutic plasma concentration is primarily related to the type and to the severity of the individual epilepsy, as indicated by the seizure frequency at the onset of the epilepsy or prior to the treatment.

Adolescent↗
PubMed1984

Autoantibodies to platelet glycoprotein IIb/IIIa and to the acetylcholine receptor in a patient with chronic idiopathic thrombocytopenic purpura and myasthenia gravis.

The coexistence of chronic idiopathic thrombocytopenic purpura and myasthenia gravis has been infrequently reported. We report another case and show the coexistence of autoantibodies to the platelet glycoprotein IIb and IIIa complex and the acetylcholine receptor. Autoantibody levels were followed during 8 weeks of treatment with cyclophosphamide, vincristine, and prednisone; the concentration of both autoantibodies fell during treatment but without measureable clinical improvement.

Adult↗
PubMed1984

Determination of 2-[N-[(S)-1-ethoxycarbonyl-3-phenylpropyl]-L-alanyl]-(1S,3S,5S)-2- azabicyclo[3.3.0]octane-3-carboxylic acid (Hoe 498) and its hydrolysis product in serum and urine.

A highly sensitive and specific enzymatic assay for the quantitative determination of 2-[N-[(S)-1-ethoxycarbonyl-3-phenylpropyl]-L-alanyl]-(1S,3S, 5S)-2-azabicyclo[3.3.0]octane-3-carboxylic acid (Hoe 498) and its hydrolysis product Hoe 498-diacid in serum and a GLC method for the simultaneous determination of both compounds in urine are described. Both methods involve extraction from the respective biological fluid using disposable C 18 columns. In serum, the enzyme-inhibiting properties of Hoe 498-diacid (Hoe 498 can readily be converted to its hydrolysis product) are utilized for the determination of both compounds concurrently. The serum extract is dissolved in buffer solution and incubated with human serum as angiotensin converting enzyme (peptidyl-dipeptide-hydrolase, EC 3.4.15.1) source and hip-his-leu substrate. The hippuric acid liberated is quantitated by HPLC. The urine extract is treated with diazomethane followed by trifluoroacetic anhydride to convert Hoe 498 and Hoe 498-diacid to their methylester, trifluoroacetyl derivatives, which are then determined simultaneously by GLC using a nitrogen specific detector.

Angiotensin-Converting Enzyme Inhibitors↗