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Biomedical subjects

P Becker

Publications and source records attributed to P Becker.

At least 109 records · Page 6Linked to original sources
PubMed1991

Spinal cord schistosomiasis. A clinical, laboratory and radiological study, with a note on therapeutic aspects.

Fourteen patients with schistosomiasis of the spinal cord are described. They fall into two groups: 7 patients had clinical and computer-assisted myelographic evidence of lesions in the conus medullaris or cauda equina, or both. The clinical picture in the remaining 7 patients was usually that of acute or subacute transverse myelitis with normal or equivocal CT myelographic appearances. Granulomas containing bilharzial ova were found in 2 female patients with conus swelling subjected to laminectomy and biopsy. In 1 of these the ova were identified as S. haematobium while in the second, unidentified bilharzial ova were found. A presumptive diagnosis of spinal cord schistosomiasis was made in the remaining 12 patients based on characteristic clinical and investigative profiles. All 13 patients tested showed evidence of bilharzial infection based on positive blood serology or the detection of bilharzial ova, or both. All but 1 patient showed at least one of the following abnormalities on CSF examination: pleocytosis, an elevated protein content and as indicated by the presence of oligoclonal IgG bands, an elevated IgG index and an increased CSF IgG synthesis rate. A CSF bilharzia enzyme-linked immunosorbent assay (ELISA) test, developed to indicate the presence of schistosomal infection within the theca, was found to be sensitive although not entirely specific for the diagnosis of spinal cord schistosomiasis. Eleven of the 14 patients showed rapid clinical improvement, 8 after praziquantel and corticosteroid treatment, 2 after operation and 1 spontaneously. Significant reductions in the CSF cell count, protein concentration and bilharzia ELISA titre, and in intrathecal antibody production, occurred following praziquantel and corticosteroid therapy. The CSF sugar level showed a significant rise. A reduction in conus size was observed in 3 patients when CT myelography was repeated after medical therapy. The normalization of most of the laboratory parameters after combined medical treatment with praziquantel and corticosteroids, together with clinical and radiological improvement, strengthened the presumptive diagnosis of cord schistosomiasis and supports the policy of early intensive medical treatment (as opposed to surgical therapy) for this condition when diagnosed on indirect evidence.

Adolescent↗
PubMed1991

Lipid and lipoprotein abnormalities in South African Indian men with myocardial infarction.

The Indian (Asian) population in South Africa has a high rate of coronary artery disease. Fasting serum lipid and lipoprotein levels were measured in 620 consecutive male survivors of myocardial infarction and compared with those of 524 healthy male volunteer controls, and the presence of hypercholesterolaemia and hypertriglyceridaemia in the patient group was related to other non-lipid coronary risk factors. All survivors and controls were below age 61 years. Total cholesterol, triglyceride and low-density-lipoprotein cholesterol concentrations varied significantly with age both in patient and control groups, whereas high-density-lipoprotein (HDL) cholesterol did not vary with age in either group. Using the 90th-percentile age-adjusted values of controls for total cholesterol (7.1 mmol/l) and triglyceride (3.0 mmol/l) as cut-off points, 287 (46%) survivors were hyperlipidaemic. Hypercholesterolaemia with or without associated hypertriglyceridaemia was the commonest abnormality: 125 (20%) patients showed hypercholesterolaemia without associated hypertriglyceridaemia; 73 (12%) had both hypercholesterolaemia and hypertriglyceridaemia and 89 (14%) hypertriglyceridaemia without associated hypercholesterolaemia. The frequency of hyperlipidaemia did not vary with age. HDL cholesterol levels below 0.66 mmol/l (10th percentile) were observed in 131 (22%) survivors. Obesity was significantly more frequent among hypertriglyceridaemic survivors, whilst diabetes and hypertension were seen more frequently in survivors with combined hypercholesterolaemia and hypertriglyceridaemia. No significant difference was noted in the frequency of smoking and family history of coronary artery disease in hyperlipidaemia and normolipidaemic patients.

Adult↗
PubMed1991

[Clinical characteristics of patients with multiple or giant peptic ulcers].

The incidence and clinical characteristics of multiple or giant ulcers (over 20 mm for duodenal ulcer or 25 mm for gastric ulcer) was evaluated among 1434 patients with peptic ulcers. For gastric ulcers, multiple and giant lesions were found in 27% and 14% of patients respectively. Among duodenal ulcers the corresponding figure were 16% and 2.4%. Patients with triple gastric ulcers have a greater incidence of massive bleeding. Patients with triple duodenal ulcers are older, have more massive bleeding and have a greater incidence of gastric retention and hypersecretion when compared to patients with single or double duodenal ulcers. Giant gastric ulcer was associated to a shorter history and more massive bleeding; giant duodenal ulcer was associated to older age, more massive bleeding and gastric retention, when compared to patients with common size ulcers.

Adult↗
PubMed1990

About the Coulomb potential in crystals.

The Coulomb potential in a crystal is discussed. It is shown that its Fourier series expansion has a singularity for the V(0, 0, 0) component, which is important when comparing different compounds, or when using the Coulomb potential as a probe for reactivity. Methods to calculate this term are discussed. Sum rules for multipolar moments of crystals in terms of structure factors are derived, which are of interest for the comparison of microscopic and macroscopic dielectric properties.

Crystallography↗
PubMed1990

Use of a centromere-specific DNA probe (p82H) in nonisotopic in situ hybridization for classification of micronuclei.

The DNA probe p82H was used to visualize centromeric DNA in micronuclei (MN) of human cells. Slides prepared from cultures treated by the aneugen (causing aneuploidy) colcemid showed significantly more MN with centromeric signals than those treated by the clastogen (causing chromosome breakage) bleomycin. These results indicate that in situ hybridization with the alphoid p82H DNA probe is a suitable method with which to distinguish between MN containing whole chromosomes and acentric fragments, and hence allows one to discriminate between the clastogenic and aneugenic effects in MN formation.

Aneuploidy↗
PubMed1990

The effects of levodopa and haloperidol on flash and pattern ERGs and VEPs in normal humans.

We investigated the effects of single doses of the dopamine agonist levodopa and the dopamine antagonist haloperidol on pattern and flash electroretinograms (ERGs) and visual evoked potentials (VEPs) in normal subjects. A placebo and two treatment regimens were administered in a randomized double-masked design. No significant intertreatment differences in the pattern ERGs and VEPs were noted. Although not statistically significant, a clearly discernible tendency was found for increased flash ERG b-wave amplitudes after levodopa administration compared with placebo. In comparison with placebo and levodopa, haloperidol was associated with significantly prolonged flash ERG b-wave implicit times, including each oscillatory potential, which also showed increased duration, particularly in the O1-O3 interpeak implicit time. The failure of pattern ERGs and VEPs to show changes after haloperidol may have been related to the timing of the recordings, which took place during the presumed phase of rising blood levels and before the flash ERG and VEP recordings. Our findings further demonstrated the reliability of the flash ERG in revealing changes in dopaminergic status in the visual system and suggest that steady-state (flicker) ERGs, cone ERGs, and oscillatory potentials have particular use in this regard.

Adult↗
PubMed1990

Radionuclide scintigraphy in tuberculous enteritis.

Scintigraphy with indium-111 labeled leucocytes and gallium-67 citrate was performed on 6 patients with proven tuberculous enteritis. The ability of both techniques to visualize areas of disease in this condition was demonstrated. When compared with endoscopy (either upper gastrointestinal endoscopy or colonoscopy), Ga-67 citrate had a sensitivity of 0.80 and a specificity of 1.00. The sensitivity and specificity of In-111 labeled leucocytes was 0.60 and 0.96, respectively. The superiority of Ga-67 over In-111 was statistically significant. Positive scintigrams were obtained despite prior treatment with antituberculous chemotherapy.

Adult↗
PubMed1990

Abnormalities in sex hormones are a risk factor for premature manifestation of coronary artery disease in South African Indian men.

The relation between sex hormone levels and myocardial infarction was studied in a case-control study among 117 Indian men with myocardial infarction aged 30-60 years and in 107 healthy Indian male controls. The patients and controls were further divided into subsets defined by age in decades. In the total patient population, testosterone concentration was significantly lower than in the controls (P less than 0.01), whilst oestradiol (P less than 0.0005) and the oestradiol to testosterone ratio (P less than 0.0005) were significantly higher. Multivariate stepwise logistic regression analyses demonstrated that free testosterone index, the free oestradiol index, and the oestradiol to testosterone ratio were significantly associated with myocardial infarction, and that this association was independent of age, body mass index, smoking and serum lipids. Further analyses according to age subsets revealed that compared to respective control groups, patients in the 4th decade had both significant hypotestosteronaemia and hyperoestrogenaemia, whereas in patients of the 5th decade significant differences in total and in the calculated free oestradiol index were noted, and in the 6th decade a significant difference was detected only in the free oestradiol index. Hence, we conclude that aberrations in endogenous sex hormones are significantly associated with myocardial infarction, and that this association appears to be strongest in young men and diminishes with age, suggesting that these disturbances in sex hormones may be associated with premature manifestation of coronary artery disease.

Coronary Artery Disease↗
PubMed1990

The effect of dust-suppressant additives on the physical properties of an irreversible hydrocolloid.

The effects of dust-suppressant additives on certain physical properties of an irreversible hydrocolloid were studied in five test specimens formulated as follows: no additives (F0); 10% Duomeen cationic surfactant in 0.5% paraffin with 0.05% zinc stearate (F1); 10% Duomeen in 0.5% paraffin with 0.10% zinc stearate (F2); 20% Duomeen in 0.5% paraffin with 0.05% zinc stearate (F3); and 20% Duomeen in 0.5% paraffin with 0.10% zinc stearate (F4). The properties tested according to ADA specifications were mixing time, setting time, compressive strength, strain in compression, and permanent deformation under fixed strain. For each property, the variances between formulations were not significantly different (Levene p less than 0.05) whereas means were significantly different for stress (ANOVA p + 0.0001; Kruskal-Wallis p = 0.0019); strain (ANOVA p = 0.0003; Kruskal-Wallis p = 0.0228); deformation (ANOVA p = 0.0166; Kruskal-Wallis p = 0.0308). For the properties stress, strain, and permanent deformation under fixed strain, the paired differences of dust suppressants were established by using Duncan's multiple range test. Duomeen, instead of zinc stearate seems to be responsible for these effects.

Alginates↗
PubMed1990

Social relations in groups of the black-capped capuchin (Cebus apella) in captivity. Interactions of group-born infants during their second half-year of life.

During the second half-year of life, capuchin monkey infants maintain close contacts to kin-related animals. Apart from these contacts, they frequently interact with other infants and juveniles 1 year older. During this period of life the 'peer phase' begins in the life of the infants. Furthermore, gender differences, especially in respect to social play, become obvious.

Animals↗
PubMed1990

A 100-element ultrasonic circular array for endoscopic application in medicine and NDT.

In this paper we focus on a new developed ultrasonic circular array for endoscopic application in medicine and NDT. The new device consists of 100 strip elements. The diameter of this array is just 10 mm. The arrays are conceived for frequencies between 3.5 and 7.5 MHz, the band width has an amount of 50%. The mathematical algorithm, monochromatic and broadband simulations of the soundfield are shown and problems with grating lobes are discussed. Furthermore the process of manufacturing is discussed and partially depicted. We present the final results and ultrasonic images obtained from tissue aquivalent phantoms representing medical application and from special test specimens representing NDT- Application.

Algorithms↗
PubMed1989

Nifedipine in acute hypertensive emergencies in pregnancy.

The effect of nifedipine (Adalat; Bayer-Miles)--a calcium channel blocker, which has a well-established place in nonobstetric hypertension--was compared with dihydralazine in 33 primigravidas with severe hypertension of pregnancy. Patients with a diastolic blood pressure greater than 110 mmHg before drug administration were randomly assigned to treatment with either nifedipine or dihydralazine. Both drugs were found to be equally efficacious. Nifedipine, however, showed an earlier onset of action in lowering systolic blood pressure and had the advantage of oral administration.

Acute Disease↗
PubMed1989

Somatosensory evoked potential measures of conduction in peripheral and central pathways in children with protein-calorie malnutrition.

The effects of malnutrition on conduction in peripheral and central somatosensory pathways in humans, as measured by short-latency somatosensory evoked potentials (SEPs) have not been previously reported. A group of 28 children with kwashiorkor were compared to a control group of 35 children, aged 6-36 months. The malnourished group had longer reciprocal conduction velocities (ms/m) for pathways between the wrists and the brachial plexi (CL1 response) and between the brachial plexi and the upper cervical region (CL1-CVN). While an individual child with kwashiorkor had abnormal intracranial reciprocal conduction velocities (CVN-N1), the inter-group differences did not attain statistical significance, possibly due to inadequate indices of central pathway lengths. These findings expand the extent of conduction delays revealed by previous studies of peripheral nerve conduction velocities in PCM.

Child, Preschool↗
PubMed1989

Normal values for simple lung function tests in South African Asian children.

Normal lung function values have frequently been shown to be racially specific. This study of 1072 boys and girls establishes normal standards for peak expiratory flow rate, forced expiratory volume in 1 s, and forced vital capacity in Asian (Indian) children aged 5-14 years. These values are compared with those of American white and black children and of Indian and British Asians.

Adolescent↗
PubMed1989

Age-related lymphocyte sub-population changes among healthy Africans from birth to adulthood.

Selected immunological tests were performed on peripheral blood samples obtained from 186 healthy Africans between birth and adulthood. Results are presented by regression analysis. There appeared to be a threshold at 5 years: rate of change of the immunological parameters studied was most rapid between birth and 5 years and least thereafter, with children over 5 years being largely similar to adults. No gender-related differences were detected. In these children, cell numbers are higher and attainment of adult values for T cells earlier than in Caucasians. Formulae are derived from the regression data which allow the prediction of normal values at any age for the parameters studied. This study may serve as a reference for those working in similar environments. The acceleration in development of immunity in black children suggested by these and other results probably indicates early and continual provocation by infections.

Adolescent↗
PubMed1989

Circulating monotypic B-cells in multiple myeloma: association with lambda paraproteins.

The peripheral blood and bone marrow mononuclear cell immunophenotype was investigated in series of 41 patients with plasma cell dyscrasias (29 with multiple myeloma and 12 with monoclonal gammopathy of undetermined significance (MGUS) or solitary plasmacytoma). A statistically significant relationship between the presence of monotypic B-cells (MBC) in the peripheral blood and the paraprotein light chain isotype was found in the myeloma patients (P = 0.0025). MBCs were documented in 71% of patients with lambda paraproteins, compared with only 13% of patients with kappa paraproteins. The difference in MBC was independent of disease stage as well as of individual prognosticators such as haemoglobin, renal function, paraprotein size and beta-2-microglobulin, although lambda producers had significantly higher calcium levels than patients with kappa paraproteins (P = 0.03). A similar trend was also noted for MBC to be found more commonly in patients with lambda producing MGUS and solitary plasmacytoma. This phenomenon may account for the worse prognosis in patients with lambda paraproteins. In our hands, immunophenotypic detection of peripheral blood involvement in plasma cell dyscrasias is more sensitive than investigation of karyotype or immunoglobulin gene rearrangements.

B-Lymphocytes↗
PubMed1989

Electrophysiological indices of central and peripheral nervous system function during theophylline therapy.

Electrophysiological parameters including the EEG, somatosensory evoked potentials (SEP), F waves, long loop reflexes and peripheral nerve conduction velocities were assessed during the 15th week of theophylline therapy, with serum levels maintained in the low therapeutic range, in young, healthy male volunteers (n = 7). Recordings were repeated 1 week after vitamin B6 supplementation and finally 6-7 weeks after the cessation of medication. Alpha amplitudes were significantly lower during theophylline therapy compared to the posttreatment baseline recording. The SEP findings failed to reveal any significant differences between the three recordings, as was the case with peripheral nerve conduction velocities and long loop reflexes. The average F wave latencies during theophylline therapy were significantly shorter, and the percentage F waves recorded was higher, compared to the baseline recordings. These findings suggest that relatively long-term theophylline therapy has stimulatory effects on aspects of electrical activity in the brain and spinal cord. These effects appeared to be unchanged after vitamin B6 supplementation for 1 week.

Adult↗