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Biomedical subjects

A Frank

Publications and source records attributed to A Frank.

At least 19 recordsLinked to original sources
PubMed1992

Effects of hypoglycemia on the cerebral circulation in awake goats.

We electromagnetically measured blood flow to one cerebral hemisphere and determined cerebrovascular reactivity to vasoconstrictor and vasodilator stimuli during normoglycemia and insulin-induced hypoglycemia in unanesthetized goats. Control blood glucose concentration was 84 +/- 4 mg, and insulin, injected intravenously, decreased glycemia with a concomitant increment in cerebral blood flow and reduction in cerebrovascular resistance in all the animals. When glycemia decreased to 60 to 65 mg/dl, the animals began to show signs of increased adrenergic activity, and when it decreased to less than 30 mg/dl, they showed signs of CNS depression. Cerebral blood flow began to rise significantly at a glycemia of 50 to 55 mg/dl, and progressively increased to reach an increment of 36% +/- 4% when glycemia was less than 30 mg/dl. Norepinephrine (0.3 to 9 micrograms), tyramine (50 to 500 micrograms), and 5-hydroxytryptamine (0.1 to 9 micrograms) reduced cerebral blood flow, and this effect was lower during severe hypoglycemia. Acetylcholine (0.01 to 1 microgram), isoproterenol (0.03 to 3 micrograms), diazoxide (0.3 to 9 mg), and inhalation of 10% CO2 in air increased cerebral blood flow, and this effect was also lower during severe hypoglycemia. The results show that insulin-induced hypoglycemia causes cerebral vasodilation and reduction of the capacity of cerebral blood vessels to constrict and dilate. They also show that the glycemic thresholds for increasing cerebral blood flow are near to, or slightly lower than, the thresholds for hypoglycemic symptoms. This experimental model of hypoglycemia closely resembles the conditions in hypoglycemic patients and permits serial evaluation of the cerebrovascular effects of hypoglycemia without using anesthesia.

Animals↗
PubMed1991

On methods of reporting clinical material.

The members of the Committee on Scientific Activities of the American Psychoanalytic Association are concerned about the paucity of clinical data in psychoanalytic reports and by the quality of what does exist. We have proposed a few standards for clinical reports that we believe will be reliable and clear and will have enduring usefulness. We recognize the need for maintaining confidentiality and, at times, for disguise; we also recognize the need to balance these requirements against the dangers of misleading the reader (or listener). These conflicting requirements have resulted in our concentrating on some general principles for clinical reporting. We have appended a tentative form, and examples, to be considered for that purpose.

Data Collection↗
PubMed1990

[Evaluation of respiratory muscle function (maximal respiratory pressures) in myasthenia gravis].

In myasthenia gravis (MG) the status of respiratory function has a paramount importance and a careful evaluation is recommended. The weakness of respiratory muscles has been demonstrated in several studies. However, a reliable simple method for the evaluation of this muscular group was lacking until recently, when the usefulness of the maximum respiratory pressures, expiratory (MEP) and inspiratory (MIP), was demonstrated. We evaluated with this method a series of 23 patients with a diagnosis of MG (16 females and 7 males), with a mean age of 46 years (22-68 years), clinically stable and without symptomatic dyspnea. They were distributed in: grade I (5), grade II A (12), and grade II B (6). All of them were evaluated with flow-volume curves, pletysmography, gas transfer, MEP and MIP. The resulting values were then correlated with the expected ones, a reduction greater than one SD being considered as abnormal. The results showed that respiratory function was normal without a restrictive pattern. However, the force of respiratory muscles was reduced in the following proportions of patients in the different groups: grade I: MIP 40%, MEP 60%; in grades II A and II B both MEP and MIP were reduced in 84% of patients. When a statistical comparison with the expected values was carried out it was found that MEP and MIP, considered as a group, were reduced to 53% of the expected values (p less than 0.05).(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1990

[Wilson's disease: computed tomography and magnetic resonance imaging].

Wilson's disease is an autosomal recessive hereditary disease in which the capacity of biliary copper excretion is reduced, resulting in a toxic accumulation of this metal in the liver, brain and other organs. The neuroimaging techniques, computed tomography (CT) and nuclear magnetic resonance (NMR), have been incorporated to the diagnostic workup in patients with suspected Wilson's disease (WD). We report two patients with WD in whom CT and NMR were carried out for the evaluation of the central nervous system (CNS). The lesions appeared as hypodense areas in CT or signal abnormalities in NMR over the involved structures: putamen, caudate nucleus, cerebellar dental nucleus, red nucleus and subcortical white matter. In one of the patients, hypointense signal areas were found over both putamen nuclei in T-2 times of NMR, which might correspond to cavitary necrosis or copper deposition. The lesion distribution suggests that vascular lesions might play a role in the mechanisms of tissue damage. These findings show that CT and NMR are very helpful to evaluate WD. NMR images are quite characteristic of this disorder.

Adolescent↗
PubMed1979

Behavior of N-methylated allopurinols and related 4-thioxopyrazolo [3,4-d]pyrimidines towards bovine milk xanthine oxidase.

1. All available N-mono- and N,N'-dimethylallopurinols and the corresponding 4-thioxo derivatives have been tested as substrates or inhibitors of bovine milk xanthine oxidase (xanthine: oxygen oxidoreductase, EC 1.2.3.2). 2. None of the compounds tested revealed any inhibitory activity towards the enzyme. 3. All compounds were resistant to enzymic oxidation, with the exception of 7-methylallopurinol and its 4-thioxo analog. Both these compounds were attacked at position 6. 7-Methylallopurinol was oxidised nearly ten times faster than the isomeric 3-methylhypoxanthine. 4. These observations can be explained by assuming that for attack at C-6, the enzyme must bind both to N-1 and N-2 in the pyrazole ring and causes tautomerisation, which places a double bond at position 5,6 in the pyrimidine ring. This activation process resembles the activation of hypoxanthine.

Allopurinol↗
PubMed1979

Surface markers and size of lymphocytes in human umbilical cord blood stimulated into deoxyribonucleic acid synthesis by Epstein-Barr Virus.

We characterized subpopulations of lymphocytes in human umbilical cord blood which are stimulated into deoxyribonucleic acid synthesis by Epstein-Barr virus. Lymphocytes were examined simultaneously for deoxyribonucleic acid synthesis by autoradiography and for surface markers by rosette formation with sheep erythrocytes or erythrocytes coated with antibody and mouse complement (EAC). The subpopulation which incorporated [3H]thymidine after exposure to virus consisted mainly of cells which formed rosettes with EAC. Lymphocytes were enriched or depleted of thymus-derived lymphocytes (T cells), null cells, or cells forming rosettes with EAC. The extent of sensitivity of the cells to stimulation by Epstein-Barr virus correlated with the proportion of the population which formed rosettes with EAC. When mononuclear cell populations were depleted of T lymphocytes and then fractionated by size, small lymphocytes showed higher rates of deoxyribonucleic acid synthesis after virus exposure and higher transformation frequency than did larger cells or unfractionated cells. Thus, the cells which are stimulated into deoxyribonucleic acid synthesis by Epstein-Barr virus appear to be the same as cells which are ultimately transformed.

DNA↗
PubMed1979

Predictors of community tenure of discharged state hospital patients.

Community treatment of formerly hospitalized patients is in need of evaluation. The authors evaluated an aftercare program by examining its effect on the amount of time spent in the community by patients discharged from a state mental hospital. They assessed the impact of specific intervention in the areas of housing, employment, finances, psychiatric treatment, medication, and leisure. They conclude that assistance during the transition from the hospital to the community prolonged community tenure, that intervention in the areas of housing, finances, and medication was especially important, and that treatment in the community increased the amount of time spent in the community during the first 6 months after discharge.

Adult↗