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Biomedical subjects

C Weiss

Publications and source records attributed to C Weiss.

At least 235 records · Page 13Linked to original sources
PubMed1984

Eyeball retraction latency in the conscious rabbit measured with a new photodiode technique.

A new technique is described for accurate, reliable measurement of eyeball retraction in the rabbit. A narrow film strip, on which a linear light intensity grating has been exposed, is attached to a contact lens which is placed on the animal's cornea. The other end of the intensity grating slides between a photodiode and an LED. The contact lens-film grating assembly moves freely with eyeball retraction and relaxation, causing changes in photodiode output. This device appears to be well tolerated by the animal. Large amplitude eyeball retractions occur in response to air puff stimulation directed at the upper or lower eyelid and to periorbital shock. Average eye retraction latency to stimulation of the abducens (VI) nerve with a chronically implanted stimulating electrode was 5.3 ms (S.D. = 0.75 ms) in the conscious rabbit as measured with our device. Latency to periorbital electrical shock was 9.3 ms (S.D. = 2.1 ms). Eye retraction latency decreased with increasing shock amplitudes. Rabbits readily acquired classically conditioned eyeball retractions, monitored with this device, when a white noise auditory stimulus was paired with an air puff directed at the eyelid.

Abducens Nerve↗
PubMed1983

[Premature birth. Retrospective study of 2000 premature births at the Gynecological Clinic of the University of Mannheim. 2: Postpartum period, morbidity and mortality of premature infants].

During a period from 1966 to 1977 a retrospective study on 1982 premature births was conducted. 9,4% of the premature births were dead born; from the births, who died in the postnatal period, 94% died within the first 7 days, perinatal mortality was 27%. Most common cause of death was immaturity (25%), followed by respiratory distress syndrome (16%), in 31% cause of death was unknown. The most common complications of the immature births were icterus neonatorum (25,3%), aspiration (21,3%) and asphyxia (8,9%).

Female↗
PubMed1983

Enzyme changes in axon, myelin, and Schwann cells in injured sciatic nerve.

Four enzymes related to specific cell functions were assayed in rat sciatic nerve injury by crush (cr) or crush and ligation (cr-lig) after 2, 7, and 15 days in situ. Enzyme activities in segments of sciatic nerve proximal and distal to the injury were compared to those in corresponding segments of the contralateral nerve. Choline acetyltransferase (CAT) activity in the distal portion decreased by 65% for cr and almost to zero for cr-lig by day 7, while in the proximal portions CAT decreased to 70% of control values by 7 days and to 50% at 15 days after cr-lig. The activity of the Schwann cell-myelin-associated enzyme 2',3'-cyclic nucleotide phosphohydrolase (CNP) decreased slowly distal to the injury. Distal to both types of injury the lysosomal enzyme beta-glucuronidase (GLR) increased six- to eightfold by 15 days. Proximal to injury GLR also increased (P cr X 2.5, P cr-lig X 5) but the peak proximally was attained by day 7. Despite interruption of axonally transported enzymes, the activities of the metabolic enzyme creatine kinase (CK) increased distal to injury apparently reflecting changes in the functions of the Schwann cells. The loss of metabolic enzymes from the axonal compartment may be completely obscured by reciprocal changes in the non-neuronal compartments if the activity is present in both compartments.

2',3'-Cyclic Nucleotide 3'-Phosphodiesterase↗
PubMed1983

The influence of estrogen administration on the subcellular receptors distribution and its biological effect in the rat anterior pituitary gland.

We studied the effects of estrogen administration in the anterior pituitary gland (APG) of male rats. The subcellular distribution of estradiol receptors, and some biological responses, such as prolactin secretion and progestine receptors were examined. In the presence of circulating estrogens, the binding of [3H]-estradiol decreased in the cytosol and increased in nuclei. The total binding augmented significantly (P less than 0.05). These changes were dose and time dependent. So, in long chronic treatment, the changes in subcellular receptor distribution were greater, in accordance with higher serum estrogen level. Serum prolactin concentration and progestin receptor in the APG increased continuously as a function of time of the estrogen treatment. They were related to the presence of nuclear estradiol receptors, which remained elevated throughout the entire experimental period.

Animals↗
PubMed1983

Danger: T.R. at work.

State credential processes may require applicant groups to specify the dangers to the public and clients of unregulated practice. A model for the equitable display of therapeutic recreation concerns is proposed as well as a classification of negative worker behaviors. The self-study process described has implications for education, personnel justifications and the development of standards and ethics.

Credentialing↗
PubMed1983

The effects of BCNU (1,3-bis(2-chloroethyl)-1-nitrosourea) and CCNU (1-(2-chloroethyl)-3-cyclohexyl-1-nitrosourea) on glutathione reductase and other enzymes in mouse tissue.

BCNU has been reported to cause a rapid, irreversible inhibition of human erythrocyte glutathione reductase (GR) at chemotherapeutic dosage, without affecting metabolic enzymes. This inhibition may mediate some of the therapeutic and toxic effects of BCNU. Thiol containing agents such as reduced glutathione can protect cells against BCNU and a change in glutathione concentrations could modify BCNU effectiveness. At doses of 50 mg/kg (LD-50) and 100 mg/kg, i.p., BCNU decreased the activity of GR in mouse kidney, liver, brain, and heart with a greater loss in those animals which died from drug administration. GR activity tended to recover but still remained below control at 96 hours. Erythrocyte GR activity was reduced only at the higher BCNU dose. CCNU (100 mg/kg, i.p.) did not affect GR activity. BCNU also decreased creatine kinase, malate dehydrogenase, and lactate dehydrogenase activities. The inhibition of GR in vitro occurred only after biochemical reduction of the enzyme with NADPH. The oxidation state of GR may determine its sensitivity to BCNU in the human erythrocyte but we were unable to demonstrate an unusually high sensitivity or a specific effect of BCNU on GR in mouse tissues.

Animals↗
PubMed1982

[A study of bromazepam in hospital practice (author's transl)].

The effectiveness of bromazepam was evaluated in 32 hospital out-patients suffering from reactional depression or anxiety-depression syndrome. Dosages ranged from 6 to 9 mg/24 hours in 3 divided doses. Results were assessed by means of a battery of tests (Hamilton's scale, self-evaluation scores of Hopkins, Pull-Guelfi's scale, Bond's psychometric tests) performed on days 0, 14 and 18. Good results were obtained in two-thirds of the patients, and these continued treatment for more than one month.

Adult↗
PubMed1981

Regional activities of metabolic enzymes and glutamate decarboxylase in human brain.

Interpretation of biochemical measurements in the human brain after death is complicated by a variety of premortem, perimortem, and postmortem factors. The activity of glutamic acid decarboxylase (GAD) in particular has been found to vary considerably among human brains. In contrast to neurotransmitter-associated enzymes, metabolic enzymes are present in all brain cells and should not be specifically lost by patterned neuronal cell loss such as that which occurs in Parkinson disease. We compared the activity of GAD to that of the metabolic enzymes creatine kinase (CK), adenylate kinase, hexokinase, beta-glucuronidase, and malate, lactate, glucose-6-phosphate, and isocitrate dehydrogenases in 24 regions of six human brains. Of the metabolic enzymes, only CK showed a 5-fold variation approaching that of GAD. Like GAD, CK activity was stable postmortem, but its activity was apparently inversely related to the severity and duration of the preterminal illness. CK may be a useful marker of agonal deterioration.

Aged↗
PubMed1981

Developmental study of rat brain glutathione peroxidase and glutathione reductase.

Glutathione peroxidase and glutathione reductase activities were measured in whole rat brains at selected ages from birth to adulthood. On a wet weight basis glutathione peroxidase activity increased 70% during development and glutathione reductase activity increased 160%. On a protein basis glutathione peroxidase declined slightly in activity during the first two weeks of life and then maintained the 14-day activity into adulthood while glutathione reductase showed a 30% increase in activity. While less than the developmental changes in many enzyme involved in aerobic glycolysis or catecholamine metabolism, these increases do suggest a role in CNS metabolism.

Aging↗
PubMed1981

Feasibility of using computerized tomography in diagnosing nasopharyngeal closure.

The feasibility of using computerized tomography for diagnosing nasopharyngeal anatomy and physiology was investigated. Ten adult subjects with normal communication were assessed with an Ohio-Nuclear Delta Scan 2020 Whole Body Computed Tomographic Scanner at two different levels of the nasopharynx during rest and production of /u/ and /s/. Lateral and anterior-posterior dimensions of the pharynx were simultaneously x-rayed and computed for each subject and condition. Computerized tomography appears to be useful in directly mapping the nasopharynx and in providing precise three-dimensional configurations without using a contrast medium.

Adult↗
PubMed1981

Coupling of dopamine oxidation (monoamine oxidase activity) to glutathione oxidation via the generation of hydrogen peroxide in rat brain homogenates.

Homogenates of perfused rat brain generated oxidized glutathione from reduced glutathione during incubation with dopamine or serotonin. This activity was blocked by pargyline, a monoamine oxidase inhibitor, or by catalase, a scavenger of hydrogen peroxide. These results demonstrate formation of hydrogen peroxide by monoamine oxidase and the coupling of the peroxide to glutathione peroxidase activity. Oxidized glutathione was measured fluorometrically via the oxidation of NADPH by glutathione reductase. In the absence of added dopamine or serotonin, a much smaller amount of reduced glutathione was oxidized; this activity was blocked by catalase, but not by pargyline. Therefore, endogenous production of hydrogen peroxide, not linked to monoamine oxidase activity, was present. These results indicate that glutathione peroxidase (linked to hexose monophosphate shunt activity) can function to eliminate hydrogen peroxide generated by monoamine oxidase and other endogenous sources in aminergic neurons.

Animals↗