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Biomedical subjects

S Berger

Publications and source records attributed to S Berger.

At least 181 records · Page 10Linked to original sources
PubMed1990

Carbon-13 labelled biotin--a new probe for the study of enzyme catalyzed carboxylation and decarboxylation reactions.

[2'-13C]Biotin was incorporated into avidin (egg white), glutaconyl-CoA decarboxylase (EC 4.1.1.70) from Acidaminococcus fermentans and the biotin carrier of transcarboxylase from Propionibacterium freudenreichii (EC 2.1.3.1). 13C-NMR measurements showed an upfield shift of the carbonyl carbon of 3.1 and 2.0 ppm for both enzymes, whereas binding to avidin induced no significant change of the chemical shift as compared to free biotin. The data indicate that the enzymes provide an electronic environment for the covalently bound biotin which favours carboxylation. In addition it was demonstrated by NMR-measurements that glutaconyl-CoA decarboxylase, from which the hydrophobic carboxy-lyase subunit (beta) was removed, could carboxylate free biotin.

Avidin↗
PubMed1990

Graduate medical education needs some new approaches.

Administrators want a more explicit system of funding graduate medical education to match costs more fairly and promote the training of more family-practice physicians, Sally Berger says.

Education, Medical, Graduate↗
PubMed1990

Nuclear magnetic relaxation studies of the role of the metal ion in Mn2(+)-substituted aminoacylase I.

Substitution of the essential Zn2+ ions of porcine kidney aminoacylase I (EC 3.5.1.14) by Mn2+ did not markedly affect the kinetic properties of the enzyme. Using Mn2+ as a paramagnetic probe, we were able to study the conformations of bound ligands by measuring the enhancement of ligand proton relaxation in 1H NMR. In addition, the effects of inhibitors on the paramagnetic enhancement of water proton relaxation rates were examined. The results of both approaches, in agreement with kinetic evidence, suggest that the metal center of aminoacylase I is too distant from the ligand binding site to allow direct participation of the metal in substrate binding or catalysis. We, therefore, propose that the metal ion of aminoacylase I plays a purely structural role.

Amidohydrolases↗
PubMed1990

1-Aryl-N2-alkyl-ethanediamines as isosters of adrenergic arylethanolamines.

A family of 1-aryl-N2-alkyl-ethanediamines 1 isosteric with the N-alkyl-arylethanolamines are described. Although the prepared compounds were generally less potent than the N-alkyl-arylethanolamines, the 1-aryl-N'-(phenylmethyl)-N-alkyl-1,2-ethanediamines derivatives 6, are more active than the debenzylated free amino analogs 1, which may be indicative of the importance of the lipophilicity of the substituent at the alpha position to the aromatic ring.

Adenylyl Cyclases↗
PubMed1990

Effects of anaesthetic agents on cerebral blood flow and brain oedema from a focal lesion in rabbit brain.

Anaesthetic agents reduce cerebral metabolism and may impair coupling of cerebral blood flow and metabolism. We analyzed the effects of isoflurane (I) (1 MAC), fentanyl (F), thiopental (T) (32.5 mg/kg x hr) and alpha-chloralose (C) on rCBF and brain oedema formation after a focal cerebral injury (cold lesion) in rabbits (n = 6 per group). In the isoflurane group, angiotensin II (0.15 microgram/kg x min) was given to maintain blood pressure. rCBF of cerebral cortex was measured 3 times per hr by H2-clearance with needle electrodes placed at different distances to the lesion during 6 hrs after induction of trauma. Thereafter, samples of white matter were obtained near the focal lesions and from corresponding areas of the contralateral hemisphere for measurement of specific gravity (SG) by a linear density column (Percoll R). Blood pressure was 78, 86, 72, and 88 mmHg for groups I, F, T, and C, respectively. After induction of the lesion, hyperemia of approximately 1 hr was observed in all groups. This was most pronounced distant to the lesion. Close to the lesion rCBF remained unchanged in groups C and T, but fell significantly below control in I and F. The blood flow response distant to the trauma was characterized by a moderate increase (C), or no alteration (T), while isoflurane animals had a pronounced secondary hyperemia for about 3 hrs. With fentanyl, however, rCBF was markedly reduced in this area. SG of white matter close to the lesion decreased significantly to values of 1.032 g/cm3 (I, F, T), or 1.031 (C), indicative of oedema. Specific gravity was 1.034 in the contralateral hemisphere (control).(ABSTRACT TRUNCATED AT 250 WORDS)

Anesthetics↗
PubMed1990

Petit mal epilepsy and parkinsonian tremor: hypothesis of a common pacemaker.

Rhythmic oscillation in neuronal systems may serve physiological purposes or may interfere with normal functions of the brain. In disorders of petit mal epilepsy and parkinsonian tremor, centrally and peripherally observable rhythmic patterns are due to network oscillations of thalamocortical cells. This article reviews the afferent mechanisms that might be critically involved in controlling the ionic conductances of thalamic neurons in the behaving organism. We propose that during active behavior the subcortical aminergic and cholinergic inputs to the thalamus act as anti-burst and anti-oscillation mechanisms. We suggest further that the thalamopetal GABAergic inputs (pars reticulata of substantia nigra, entopeduncular nucleus, pallidum) are burst- and oscillation-promoting systems, whose output is controlled by the striatum. Experimental or disease-related decrease of the striatal dopamine levels is hypothesized to increase the efficacy of the GABAergic burst-promoting systems resulting in rhythmic network oscillation of thalamocortical neurons during rest. The recognition of the overlapping neuronal mechanisms in petit mal epilepsy and parkinsonian tremor, and the multistage control of thalamic oscillation suggests that drugs effectively used in petit mal attacks may be effective in levodopa-refractory parkinsonian tremor, and conversely, epileptic patients may benefit from drugs acting on the extrapyramidal system.

Epilepsy, Absence↗
PubMed1990

Designing services for the elderly.

Even after careful planning and a successful launch, even the best geriatric care program can not always expect smooth sailing, according to industry executives. Allen Mathies, president and chief executive officer at Huntington Memorial Hospital, cited a paradoxical side effect stemming from the success of his hospital's geriatric outreach programs. "On the one hand, by moving patients through a continuum of outpatients services, our program has helped to reduce the extraordinary costs associated with acute care hospitalization," he said. "On the other hand, those patients who are hospitalized tend to be more acutely ill. They use tremendous resources, but at a fixed reimbursement. There is a lack of recognition of our real costs by the payer." Why, then, do Huntington Memorial Hospital, Baptist Medical Center of Oklahoma, Morton F. Plant Hospital, Northwestern Memorial Hospital and other hospitals intend to continue their efforts on behalf of their communities' aging populations? The answer is that, reimbursement problems notwithstanding, benefits can be derived from making a commitment to geriatric care. "We have 19,000 people enrolled in our elder care program," Hupfeld said. "That's a powerful force. They vote. They lobby on our behalf. They support the hospital philanthropically. If you do a good job of reaching the older adults in your community, you'll find they are a powerful marketing force. They can do a lot for your image when it comes to reaching other market segments."

Aged↗
PubMed1990

A comparative study of Canadian nonclinical and British pain clinic subjects.

Forty-six pain clinic patients (British) were compared with 143 nonclinical subjects (Canadian) on a variety of demographic and illness variables. A subset of 43 nonclinical subjects was further compared with the 46 pain clinic patients for depression and illness behaviour. Both groups were well matched for age, sex, and marital status. The nonclinical group was better educated and had higher incomes. The nonclinical group was significantly more socially active. Low back pain, joint pain, and head and chest pain were commonly reported by both groups. Nearly 75% of subjects in both groups were aware of the diagnosis for their pain condition. On Beck Depression Inventory both groups scored in the nondepressed range. On the Illness Behaviour Questionnaire the pain clinic group scored significantly higher on disease conviction, somatization, and denial than did the nonclinical sample.

Age Factors↗
PubMed1990

Reading warning signs could save your job.

This is the last of a two part series about how CEOs should learn to read the warning signs of trouble from the hospital board. Part one, printed in the June issue of AOHA Today, followed the case of a hospital administrator who was praised by board members just two weeks before he was fired. This administrator found out the hard way that he was the victim of an informal relationship between a top hospital manager and a powerful board member. His problem is only one of many that could cause termination, and the authors' goal is to alert CEOs before problems begin. Part one gave tips for incoming CEOs to follow; part two picks up here with many more points for new and seasoned CEOs alike.

Employment↗