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Biomedical subjects

A Visser

Publications and source records attributed to A Visser.

At least 73 records · Page 4Linked to original sources
PubMed1994

Climacteric and menopause in seven South-east Asian countries.

The menopause is universal, but what about the climacteric? In an attempt to answer this question, a study was conducted in seven south-east Asian countries, namely, Hong Kong, Indonesia, Korea, Malaysia, the Philippines, Singapore and Taiwan. Samples of approximately 400 women in each country were questioned about a number of climacteric complaints, incontinence and dyspareunia, consultation of a physician, menopausal status and several background characteristics. Special care was taken to overcome linguistic and cultural problems, and the data collected were kept as objective as possible. From the results obtained we were able to show that the climacteric was indeed experienced in south-east Asian countries, although in a mild form. The prevalence of hot flushes and of sweating was lower than in western countries, but was nevertheless not negligible. The percentages of women who reported the more psychological types of complaint were similar to those in western countries. The occurrence of climacteric complaints affected perceived health status. A physician was consulted for climacteric complaints by 20% of the respondents, although this was most frequently associated with the occurrence of psychological complaints and less so with that of hot flushes and sweating. The median age at menopause (51.09) appeared to be within the ranges observed in western countries. Ethnic background and age at menarche were found to have a significant influence on age at menopause. The study clearly demonstrated that climacteric complaints occur in south-east Asia. The findings suggest, however, that vasomotor-complaint-related distress might be 'translated' into psychological complaints, which are more frequently considered to warrant consulting a physician.

Adult↗
PubMed1994

Public cancer information by GPs: evaluation of a Dutch campaign.

A postal survey among Dutch general practitioners (N = 259) investigated to what extent GPs acted as intermediaries in the provision of information about cancer, in order to encourage patients to consult their general practitioners with questions about cancer. The GPs received a box with three types of folders and a poster free of charge. Only few GPs showed resistance to the unsolicited reception of information material. They were positive towards the Dutch Cancer Society and considered it part of their task to provide patients with information about cancer. Nearly all GPs placed the box with folders in their waiting rooms, while 43% put up the poster. The leaflet and the poster entitled 'Don't walk around with questions' were negatively assessed by around half of the GPs due to the generalized information about cancer, which they felt might arouse fear. The GPs tended to make use of the information material if they had a positive opinion of it, ascribed themselves a role in providing information about cancer, and had positive expectations of the campaign. Biographical factors and characteristics of the GPs practice had hardly any influence on the use of the information material. The practical implication and research method used are discussed. Additional study among patients is stressed.

Family Practice↗
PubMed1994

Current perspectives on AIDS/HIV education and counseling.

This whole issue of Patient Education and Counseling is devoted to current perspectives on AIDS/HIV education and counseling. The results of 15 completed empirical studies and empirically-based reviews are described, highlighting the central role of education and counseling in research and clinical practice in the AIDS/HIV arena in the USA, UK, Australia, The Netherlands, and Israel. The articles concern: readability of educational materials, format of informed consent, participation of drug users in HIV-testing, measurement of condom use, safe sex among the young and non-monogamous, sexual network analysis, high-risk sexual behavior among gay men, prostitution, public reactions towards people with AIDS, teachers' attitudes towards AIDS, measurement of mental adjustment to AIDS, influencing quality of life by counseling, satisfaction with HIV counseling, the influence of psychosocial factors on the course of HIV infection, and a report on the recently held 10th International Conference on AIDS.

Counseling↗
PubMed1994

Masticatory electromyographic activity in healthy young adults and myogenous craniomandibular disorder patients.

UNLABELLED: The electromyographic (EMG) activity of the masseter and the anterior temporalis muscles were compared between 60 healthy controls and 61 myogenous craniomandibular disorder (CMD) patients. Subjects were asked to clench at 10% and at 50% of their maximum voluntary clenching level. The effects of CMD, age and gender were statistically analysed with the use of the analysis of covariance. The correlations between EMG asymmetries and the lateral slide from the retruded contact position to the intercuspal position and the asymmetry in the number of post-canine tooth contacts between the left and the right side were investigated. The CMD patients showed lower masseter EMG activities than the controls, whereas the anterior temporalis EMG activity was not different between the two groups. The activity index, relating the anterior temporalis EMG activity to the activity of the masseter muscles, confirmed the presence of a relatively high temporalis activity in the CMD group. No significant differences were found in the EMG asymmetries between the controls and the CMD patients. Males showed higher masticatory EMG activities than females. These gender effects were significant for the anterior temporalis at the 10% and 50% level and for the masseter muscle at the 10% level. The anterior temporalis EMG activity declined with age. No age related effects were observed in the masseter EMG. The lateral slide was larger and more prevalent in the CMD group. A significant correlation between the lateral slide and the anterior temporalis EMG was found for the CMD group at the 10% level. No correlation was found between the EMG asymmetry and the asymmetries in post-canine tooth contacts. IN CONCLUSION: significant CMD, age and gender effects were observed in the masticatory EMG activities of a group of myogenous CMD patients and a control group.

Adolescent↗
PubMed1994

Differential expression of ICAM-1, E-selectin and VCAM-1 by endothelial cells in psoriasis and contact dermatitis.

Adhesion receptors on endothelial cells are considered to be important for cellular influx in tissue. In this regard, skin constitutes a specialised environment for migration of leukocytes during inflammation. Using immuno-enzymatic staining techniques, we compared the in situ expression of ICAM-1, E-selectin, and VCAM-1 on endothelial cells and inflammatory infiltrates in both lesional and non-lesional biopsied skin from two immuno-inflammatory diseases, viz. psoriasis and contact dermatitis. The results were compared with those in skin specimens obtained from normal healthy individuals free from any history of skin disease. Our results show that ICAM-1 and ELAM-1 are upregulated in psoriatic non-lesional and lesional skin. On the other hand, in non-lesional biopsy from contact dermatitis patients, all three AR molecules are sparsely present, similar to the situation in normal skin although they are overtly expressed in the lesional sites. Moreover, VCAM-1 was found to be significantly increased on endothelial cells in the lesional sites of contact dermatitis as compared with biopsied psoriatic specimens. Interestingly VCAM-1 was also found to be present on some T-cells and Langerhans cells in contact dermatitis alone. The present data suggest that in different inflammatory dermatitis, varying adhesion receptor-ligand interactions involving endothelial cells and leukocytes are involved, which may be due to the differing cytokine profiles of perivascularly located T-cells.

Cell Adhesion Molecules↗
PubMed1994

Cellular interactions and adhesion molecules in psoriatic skin.

T-cell activation probably plays the most important role in hyperproliferation of keratinocytes in psoriasis. We present here our results concerning the interacting immunocompetent cells and their phenotypic and functional characteristics in relation to psoriasis pathology. Immunohistochemical analysis of skin biopsies from psoriasis patients, did indeed show that hyperproliferation of keratinocytes is associated with increased vasculature and increased influx of MHC class II molecules expressing immunocompetent cells. Furthermore, in psoriasis, several adhesion molecules and other relevant activation markers were found to be upregulated even in the non-lesional psoriatic skin, indicating that psoriatic skin in general is in an activated state. This interpretation is further supported by the observation that the expression of several AR and other relevant activation markers when compared with those in non-lesional skin from contact dermatitis are increased in a significant manner in the non-lesional skin of psoriasis patients. We have then followed up our investigations by generating T-cell lines from lesional psoriatic skin and studied their adhesion patterns on cultured endothelial cells in order to get better insight into the migration pattern of different T cell subsets in psoriasis pathology. Our results indicate that different T-cell subsets CD4+, CD8+ (both TCR-alpha beta+) CD4-/CD8+ TCR-gamma delta+ and CD4-CD8-TCR-gamma delta (V delta 1-) T-cells can easily be generated from psoriatic patients. In a comparative kinetic study using unstimulated and stimulated cultured human umbilical vein endothelial cells, we observed that TCR-gamma delta T cells showed different adhesion properties from that of TCR-alpha beta+ T cell subsets.(ABSTRACT TRUNCATED AT 250 WORDS)

Cell Adhesion↗
PubMed1993

Dissociation of heparin-dependent thrombin and factor Xa inhibitory activities of antithrombin-III by mutations in the reactive site.

Antithrombin-III (AT-III) is a heparin-dependent inhibitor of thrombin and Factor Xa, two serine proteases that are crucial for blood coagulation. In order to assess whether it would be possible to target AT-III only towards Factor Xa, we replaced parts of the reactive site, or P region, of AT-III by sequences present in prothrombin, a substrate of Factor Xa in the coagulation cascade. We show that replacement of the P3 to P3' region generates the hypothesized phenotype. In fact, point mutation of the P1' site from Ser (present in AT-III) to Ile (present in prothrombin) is sufficient to dissociate heparin-dependent thrombin and Factor Xa inhibitory activities. Interestingly, a combined mutation at P3 and P3' brings about the same dissociation. We show that besides Ile, other amino acids at P1' can lead to the dissociation in inhibitory activity. Amino acids with small side chains (Gly, Ser, Ala, and Thr) have only a marginal effect on the inhibitory activity against either protease. However, larger residues at the P1' position abolish the heparin-dependent anti-thrombin activity, whereas the heparin-dependent anti-Factor Xa activity is not at all or only moderately affected. These results can be rationalized by a comparison of the x-ray structure and a three-dimensional model of the S1' binding pockets of thrombin and Factor Xa, respectively. It appears that the S1' pocket of Factor Xa leaves much more space for the P1' residue of AT-III than the S1' pocket of thrombin.

Amino Acid Sequence↗
PubMed1992

Lack of therapeutic gain when low dose rate interstitial radiotherapy is combined with cisplatin in an animal tumour model.

The interaction of cisplatin with low dose rate interstitial radiotherapy was studied in an animal tumour model with a range of dose rats commonly used in clinical low dose rate brachytherapy. Small pieces of R1-rhabdomyosarcoma were implanted subcutaneously in the flanks of female Wag/Rij rats. When the tumour had grown to the desired treatment volume, four afterloading catheters were inserted in the tumour in a square geometry, and a fixed spacing was attained by means of a template. Subsequently, four 2 cm Ir192 wires were inserted. A range of tumour doses of 20-120 Gy at a mean dose rate of 48 cGy/h was applied; 15 mins before the implant an intraperitoneal bolus injection of 3 mg/kg cisplatin was given. For growth delay and cure rate, no modification of the effects of low dose rate brachytherapy by the addition of cisplatin was observed. The observed effects of the combination of cisplatin with low dose rate interstitial radiation in relation to the animal tumour are discussed.

Animals↗
PubMed1992

Masticatory muscle activity in different jaw relations during submaximal clenching efforts.

The EMG activities of the masseter muscles and the anterior and posterior parts of the temporalis muscles were investigated in different vertical and sagittal jaw relations. Surface EMG recordings were made. Relative muscle activities were quantified by means of the Activity Index and the Asymmetry Index. Ten subjects with a healthy masticatory system were asked to clench at 10% and 50% of their maximum voluntary clenching level. Registrations were made during clenching in the intercuspal position, on a thin stabilization splint (SSP, 1-2 mm increase of vertical dimension at first molar), on a thick stabilization splint (3 mm thicker at the incisal edge relative to SSP), and on a protrusive re-positioning splint (3 mm protrusive to SSP). The masseter EMG amplitudes were the same for all the jaw positions investigated. However, at the 10% clenching level, the temporalis muscle activity decreased after the vertical dimension was raised and decreased further after the mandible was protrusively positioned (p less than 0.01). An independent function for the posterior and the anterior parts of the temporalis muscle was not found in any of the intermaxillary jaw relations investigated. At the 50% clenching level, a decrease in anterior temporalis muscle activity was observed only with the protrusive position in relation to the other three positions. Also at this level, the index relating the activity of the anterior to that of the posterior part of the temporalis muscle was not different between jaw positions. Raising the vertical dimension and protrusive positioning of the mandible decrease the activity of the temporalis muscles. This may be a factor related to the therapeutic effect of the stabilization splint in the treatment of craniomandibular disorder patients.

Adult↗
PubMed1990

Inhibition of the early stages of the thrombin generation reaction by various glycosaminoglycans.

Inhibition of thrombin generation was studied in strongly diluted human plasma by continuously measuring the splitting of the thrombin-specific chromogenic substrate S2288 as a function of the inhibitor concentration. To avoid the activation of clotting cascade proenzymes other than prothrombin, the thrombin generation reaction was initiated by a mixture of calcium, phospholipids and (bovine) factor Xa. Using this assay we have estimated the relative potency of the following glycosaminoglycans: heparin; a fraction of heparin with high affinity for antithrombin III (high affinity heparin); the low molecular weight heparin Fragmin; the low molecular weight heparinoid Org 10172; a fraction of Org 10172 with high affinity for antithrombin III (high affinity Org 10172) and the O-methyl derivative of the pentasaccharide, representing the minimal structure required for binding to antithrombin III. Based on concentrations expressed in amidolytic anti-Xa units, the descending order of potency observed is: Heparin approximately High Affinity Heparin greater than Fragmin greater than Org 10172 greater than High Affinity Org 10172 greater than O-methyl pentasaccharide. The more potent the glycosaminoglycan the stronger the concentration dependence of its inhibitory effect. These findings could be due to the different, additional anti-thrombin activities of these glycosaminoglycans and/or to their different anti-prothrombinase activities. With the pentasaccharide a striking saturation of the inhibition is observed, due to saturation of the antithrombin III.

Antithrombins↗
PubMed1989

Complexing of copper in drinking water samples to enhance recovery of Aeromonas and other bacteria.

The presence of copper in drinking water samples at concentrations as low as 10 micrograms/l resulted in a rapid die-off of aeromonads. Coliform bacteria, heterotrophic plate count bacteria and faecal streptococci were also sensitive to copper but to a lesser degree than aeromonads. The effect was particularly noticeable in soft water (less than 3 meq/l Ca + Mg) and at pH-values below 8.0. The toxic effect of copper concentrations up to 500 micrograms/l could be neutralized for a period of up to 24 h by the addition to samples of 50 mg/l of disodium-ethylene-diamino-tetraacetate (Na2EDTA) and keeping the samples on melting ice.

Aeromonas↗
PubMed1987

Expression of the second calcitonin/calcitonin gene-related peptide gene in Ewing sarcoma cell lines.

The existence of two closely related calcitonin (CT)/CT gene-related peptide (CGRP) genes has been recognized in rat and man. In man, expression of the CALC-I gene produces CT and/or CGRP-I mRNA, whereas CGRP-II mRNA is transcribed from the CALC-II gene. Until recently, expression of the CALC-II gene had been detected only in a metastasis of medullary thyroid carcinoma. In this study, expression of the CALC-II gene was demonstrated by Northern blot hybridization analysis in four of six cell lines established from different Ewing sarcomas, a malignant neoplasm of bone. Expression of the CALC-I gene was not detected in any of the six cell lines. A presumed large mol wt immunoreactive precursor of CGRP-II and small amounts of mature CGRP-II, but no CT, were found in medium from IARC/EW 1 cells. Nucleotide sequence analysis of cloned cDNA from this cell line confirmed the production of CGRP-II mRNA. CALC-II gene expression in Ewing sarcoma might be useful for studies concerning regulation of gene expression in the CALC gene family and possibly for tumor classification.

Base Sequence↗
PubMed1986

Structure and expression of the human calcitonin/CGRP genes.

Recently, we have reported the isolation of cDNA encoding a second human calcitonin gene-related peptide (hCGRP-II) [(1985) FEBS Lett. 183, 403-407]. In this report we describe the isolation and characterization of the gene encoding hCGRP-II. This gene, designated CALC-II, is structurally closely related to the known CALC-I gene encoding human calcitonin (hCT) and hCGRP-I. In contrast to CALC-I, CALC-II does not seem to be alternatively expressed. The formation of a second, hCT-like mRNA by differential splicing of CALC-II transcripts is unlikely in view of the structure of CALC-II, and could not be demonstrated in tissues known to express CALC-I and CALC-II.

Amino Acid Sequence↗