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Biomedical subjects

M Albert

Publications and source records attributed to M Albert.

At least 145 records · Page 8Linked to original sources
PubMed1988

Cardiovascular effects of AVP and ANG in experimental pulmonic stenosis in rats.

Our objectives were to examine the role of vasopressin and renin in the regulation of peripheral vascular tone in an animal model of right ventricular failure due to chronic (10 wk) pulmonic stenosis. We tested in chronically instrumented conscious control rats and in rats with pulmonic stenosis on a normal and a high-sodium diet both vasoconstrictor systems by applying specific inhibitors. The rats with pulmonic stenosis showed significant hemodynamic changes, a hypertrophy of the right ventricle, increased levels of plasma renin concentration, and inappropriately elevated plasma levels of vasopressin in comparison to control animals. Plasma renin concentration was suppressed in the sodium-loaded controls. After the administration of a specific inhibitor of the vascular receptors of arginine vasopressin [30 micrograms, d(CH2)5Tyr(Me)AVP], we found no hemodynamic changes in control rats on the normal diet, a reduction of mean arterial pressure in the sodium-loaded controls (4 +/- 4 mmHg; P less than 0.005), and in the animals with pulmonic stenosis and normal sodium intake (5 +/- 5 mmHg; P less than 0.001) and high-salt diet (6 +/- 7 mmHg; P less than 0.02). Intravenous bolus injection of teprotide (1 mg/kg) resulted in a decrease of mean arterial pressure in the control group (normal diet) of 9 +/- 8 mmHg (P less than 0.005). The fall of blood pressure (22 +/- 10 mmHg; P less than 0.001) in the rats with pulmonic stenosis was significantly greater (P less than 0.01) and was strongly related to plasma renin concentration. Therefore, vasopressin and the renin-angiotensin system contribute to an increase of peripheral vascular tone in chronic pulmonic stenosis.(ABSTRACT TRUNCATED AT 250 WORDS)

Angiotensin II↗
PubMed1987

Ganglioside composition of an experimental mouse brain tumor.

The ganglioside composition of an experimental ependymoblastoma was examined in C57BL/6 mice. This tumor was produced by Dr. H. Zimmerman in 1949 from methylcholanthrene implantation in the brain and has been maintained in serial transplants through many generations. The influence of tumor environment on ganglioside composition was determined by studying the tumor growing intracerebrally and s.c. (over the skull and in the flank). The ganglioside composition of this tumor is markedly different from that of adult mouse brain. The total ganglioside sialic acid content (micrograms/100 mg dry weight) of the tumor growing in the cerebrum, s.c. over the skull, and in the flank was 70.4 +/- 3.8 (N = 3), 66.8 (N = 2), and 41.7 +/- 0.7 (N = 3), respectively. These values are about 10-fold lower than the ganglioside content of normal mouse cerebrum. This tumor contained a significant amount of N-glycolyneuraminic acid (NGNA). Histological analysis revealed two basically different cell types. The predominant cell type is densely packed and poorly defined in shape, whereas the minor cell type is less densely packed and fibroblastlike in shape. GM3, which migrates as double bands on thin-layer chromatography, is the predominant ganglioside of this tumor in all three regions of growth. Also present in all regions are gangliosides NGNA-GM3 and GM1. Significant amounts of GD1a, GD1b, GT1b, and GQ1b are present only in the cerebral tumor. These gangliosides therefore represent contaminants from normal brain tissue surrounding the tumor and are not native to the tumor. Ganglioside GD3, however, is a minor component of the tumor. Using a thin-layer chromatography-immunostaining method with anti-GA1 antibody, we found significant amounts of ganglioside with a GA1 oligosaccharide backbone migrating near GD3 and GD2. This tumor is similar to other neural tumors in having elevated amounts of GM3 and reduced amounts of total ganglioside and polysialogangliosides but is unique in having a high content of NGNA-containing gangliosides. The possible origin of the NGNA-containing gangliosides is discussed.

Animals↗
PubMed1987

Physostigmine-induced myoclonus in Alzheimer's disease.

Physostigmine caused myoclonus in two patients with Alzheimer's disease during a clinical trial. Neither patient had myoclonus before or after physostigmine treatment. We hypothesize that physostigmine reduced the sensitivity of the remaining muscarinic receptors in these two patients, altering the interaction between cholinergic and either serotoninergic or dopaminergic neurotransmitter systems.

Acetylcholine↗
PubMed1987

Lecithin: absence of neurophysiologic effect in Alzheimer's disease by EEG topography.

Ten patients with Alzheimer's disease participated in a 26-week double-blind trial of lecithin. EEG data were recorded at baseline, after administration of the placebo, and after administration of the drug. Topographic maps of EEG spectra were compared when patients were on and off drugs. A direct comparison of drug and nondrug data was not significant. A second approach, comparing differences between drug and nondrug with differences between the two nondrug conditions, also produced no evidence of a drug treatment effect. The data confirm other reports that lecithin has no effect upon spectrally analyzed EEG activity in Alzheimer's disease.

Aged↗
PubMed1987

Health screening to promote health for the elderly.

Reliable, specific, cost-effective health screening strategies can determine a particular client's health risks. Once those risks are known, the health care provider can develop an individualized program of health promotion to help the client move toward optimal well-being. In order to be cost effective, such a program must be aimed at the health problems most common in the particular population. The research on health screening in the elderly is incomplete. Frequently, the most sensitive screens for common problems are much too expensive to apply to an asymptomatic population, while those that are inexpensive are relatively insensitive. This article reviews the literature and attempts to assemble a set of screening strategies that can be used regularly on members of an elderly population. Counseling approaches intended to reduce an elderly person's risk of major health problems are also reviewed.

Accident Prevention↗
PubMed1986

Genetic screening for artificial insemination by donor (AID). Results of a study on 676 semen donors.

We report the results of our ten-year experience in the Centre for Study and Conservation of Human Semen (CECOS) in Paris-Bicêtre. A total of 676 potential semen donors were interviewed by a geneticist and karyotyped; 6.0% were excluded, i.e. 2.6% for a cytogenetic reason and 3.4% for a genic reason. Our experience stresses the subjectivity and difficulty of the exclusion decision. It also shows how useful it is to take into account the recipient's familial pathology when choosing the donor. Finally, it reveals the importance of the geneticist's participation in the functioning of a centre.

Chromosome Aberrations↗
PubMed1985

Muscarinic acetylcholine receptors in Alzheimer's disease. In vivo imaging with iodine 123-labeled 3-quinuclidinyl-4-iodobenzilate and emission tomography.

In vivo imaging of muscarinic acetylcholine receptor binding function in a patient with Alzheimer's disease, using single-photon emission computed tomography and iodine 123-labeled 3-quinuclidinyl-4-iodobenzilate (123I-QNB), and perfusion imaging using 123I-N-isopropyl p-iodoamphetamine are described. A profound decrease in perfusion to the posterior temporal and parietal cortex and a more uniform uptake of 123I-QNB throughout the cerebral cortex were observed. The 123I-QNB activity ratio was reduced compared with that of a normal age-matched subject, suggesting a moderate impairment in muscarinic receptor binding function in Alzheimer's disease. Furthermore, and more importantly, our study demonstrates that images of in vivo receptor binding can be obtained easily and nontraumatically using 123I-QNB and single-photon emission computed tomography.

Alzheimer Disease↗
PubMed1985

Lexical retrieval in healthy aging.

Lexical retrieval for common nouns and verbs was measured using 2 picture naming tests in 162 healthy female and male subjects aged 30 to 79 years. Responses were scored for correctness, responsivity to cueing, and response type. The ability to name both word types declined with age, especially after age 70 in healthy subjects. More errors were made on object names than action names, especially for older subjects. Subjects of all ages were equally able to utilize phonemic cues. With increasing age subjects produced more circumlocutions and fewer semantic errors. Response type difference need not reflect qualitative differences in lexical retrieval; rather, they reflect the quantitatively greater difficulty of the task for healthy older people as compared to younger adults. The naming difficulty for healthy aging, we conclude, is at the label retrieval stage.

Adult↗
PubMed1984

Ventricular size in patients with presenile dementia of the Alzheimer's type.

The computed tomograms (CTs) of eight mild to moderately impaired patients with presenile dementia of Alzheimer's type (aged 53 to 64 years) were compared with scans of ten healthy age-matched controls. Two computer programs and a variety of linear measurements were used to analyze the CTs. A single computerized measure of fluid volume on the slice at the maximum width of the bodies of the lateral ventricles correctly predicts the group membership of 88.89% of the subjects. Computerized measures on other CT slices do not increase discrimination between the groups. Easily performed linear measures correctly predict the group membership of 78.9% of the subjects. Computerized measures of ventricular size may provide highly valuable information for the diagnosis of Alzheimer's disease in the presenile age range.

Aged↗
PubMed1984

CT density numbers in patients with senile dementia of the Alzheimer's type.

The computed tomograms (CTs) of 13 mild to moderately impaired patients with senile dementia of the Alzheimer's type (aged 65 to 82 years) were compared with CTs of 18 healthy age-matched controls. Two computer programs and a variety of linear measurements were used to analyze the CTs. A measure of the mean CT density number of the brain tissue on the slice at the maximum width of the bodies of the lateral ventricles correctly predicts the group membership of 77.42% of the subjects. The addition of a second computerized variable, the fluid volume on the slice at the maximum width of the third ventricle, increased discriminating power to 93.55%. The CT density numbers may provide highly valuable information for the diagnosis of Alzheimer's disease in the senile age range.

Aged↗
PubMed1984

The clinical utility of the dementia rating scale for assessing Alzheimer patients.

Community residing patients with mild (n = 18) or moderately severe (n = 16) Alzheimer's disease and controls (n = 23) were given Mattis' Dementia Rating Scale (DRS) and a brief measure of confrontation naming selected from the Boston Naming Test (BNT). The DRS was shown to be a reliable and clinically useful measure of mental status in patients with Alzheimer's disease. The DRS subscales and the BNT had excellent internal consistency reliabilities and the total DRS score (TDRS) was shown to be generally unrelated to gender and education. Among the dementia patients, performance on the TDRS was significantly associated with functional competence. The two dementia samples had similar profiles on the DRS and BNT, with the mild subjects performing significantly better than the moderately severe subjects on each measure. Extending the range of DRS subscales would improve this measure's utility as an evaluation instrument.

Activities of Daily Living↗
PubMed1984

Strain differences in the concentration, motility and morphology of epididymal sperm in relation to puberty in mice.

Changes in the concentration, motility and morphology, of epididymal sperm have been evaluated in males of between 40 and 100 days of age in BALB, CBA, C3H and C57BL strains of mice. Particular attention was paid to sperm morphology, and a multiple entry classification system was used for its quantitation. At 40 days in each of the 4 strains studied sperm were few in numbers with poor motility and highly atypical morphology, particularly in the head region. From 80 days of age values for the 3 parameters were within the normal range. At equivalent ages during puberty the 4 strains differed in the concentration and motility of epididymal sperm, indicating difference in the time of onset of puberty between the strains. However, once adulthood was reached the strains differed only in the percentage of normal forms and in the frequency distribution of sperm with the various morphological abnormalities.

Aging↗
PubMed1983

Lateralization for pure tone perception as a function of age and sex.

Pure tone thresholds were obtained for right and left ears from 195 males and 82 females aged 24-84. Right ear advantages were present and increased with advanced age for the males; no ear differences were found for females. These data may explain contradictions in the dichotic listening literature testing lateralization for language across the lifespan.

Adult↗