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Biomedical subjects

A de Boer

Publications and source records attributed to A de Boer.

108 records · Page 6Linked to original sources
PubMed1990

Disintegration of adhesion plaques in chicken embryo fibroblasts upon Rous sarcoma virus-induced transformation: different dissociation rates for talin and vinculin.

The localization of talin and vinculin in chicken embryo fibroblasts (CEF) during transformation was studied by immunoelectron microscopy. CEF cells were infected with a temperature-sensitive mutant of Rous sarcoma virus. After 16 h at 42 degrees C, transformation was induced by incubation at 37 degrees C for different intervals up to 3 h. Cells were cleaved by "wet cleaving" as reported previously by us (R. Brands and C.A. Feltkamp, 1988, Exp. Cell Res. 176, 309) and labeled with affinity-purified polyclonal antibodies to talin or vinculin, or monoclonal anti-vinculin. We observed a rapid reduction of vinculin in adhesion plaques within 15 min and a much slower dissociation of talin. This was found using single-labeling procedures and also within the same cell using double labeling. Seemingly intact microfilament bundles were observed associated with adhesion plaques that contained relatively little vinculin. These observations show that an early event in src-induced transformation is the release of vinculin from adhesion plaques. Furthermore, since adhesion plaques with attached filament bundles can exist at least transiently with very little or no vinculin present, it seems likely that vinculin is not, or not the only protein, linking actin filaments to adhesion plaques.

Animals↗
PubMed1990

Interaction of the combined medication with the new low-molecular-weight heparinoid Lomoparan (Org 10172) and acenocoumarol.

A high intravenous dose of the low-molecular-weight heparinoid Lomoparan (Org 10172) was administered to 6 healthy males in a steady state of anticoagulation (Thrombotest) by acenocoumarol. Prothrombin time, activated partial thromboplastin time and Stypven time were prolonged to a degree which was greater than that expected on the base of the summation of the effects by each drug alone. This effect was observed for a period of up to 1 h. The Thrombotest was affected for up to 5 h after the intravenous administration of Org 10172, therefore it is deemed unsuitable for monitoring the combined effects of these two anticoagulants during this period. Acenocoumarol did not affect the pharmacokinetic parameters of Org 10172 with the exception of a slight reduction of the clearance of plasma anti-Xa activity.

Acenocoumarol↗
PubMed1990

Detection of drug interactions with single dose acenocoumarol: new screening method?

In this study, a design for the evaluation of drug interactions with an oral anticoagulant drug was investigated. The interaction between a single dose of acenocoumarol and cimetidine or pentobarbitone was studied. Nine healthy volunteers received three treatments: 1) 10 mg acenocoumarol in combination with cimetidine, 2) 10 mg acenocoumarol in combination with placebo, 3) 10 mg acenocoumarol after one week pretreatment with pentobarbitone. The pharmacokinetics and the pharmacodynamics of acenocoumarol were monitored for 36 h. In all subjects the plasma concentration of acenocoumarol remained consistently higher during cimetidine treatment and consistently lower after pentobarbitone pretreatment compared to placebo treatment. Cimetidine increased the anticoagulant response of acenocoumarol as measured by the Thrombotest and pentobarbitone decreased this response in all subjects. It is concluded from this study that both pharmacokinetic and pharmacodynamic drug interactions with acenocoumarol (and presumably other oral anticoagulants) can be detected after single doses, possibly obviating the use of long-term anticoagulation in healthy volunteers.

Acenocoumarol↗
PubMed1986

An enzyme-linked immunosorbent assay (ELISA) for the measurement of plasmin-alpha 2-antiplasmin complex in human plasma--application to the detection of in vivo activation of the fibrinolytic system.

An enzyme-linked immunosorbent assay (ELISA) is developed for the measurement of plasmin-alpha 2-antiplasmin complex in human plasma. Microtiter plates were coated with a mixture of two murine monoclonal antibodies directed against human alpha 2-antiplasmin and bound plasmin-alpha 2-antiplasmin complex was quantitated with a peroxidase-conjugated monoclonal antibody directed against human plasminogen. The lower limit of sensitivity of the assay was 0.01 nM of plasmin-alpha 2-antiplasmin complex in 100-fold diluted human plasma, allowing detection of 1 nM in undiluted plasma samples. After 100-fold dilution of the plasma samples, the assay was no longer influenced by the presence of the precursors plasminogen and alpha 2-antiplasmin. At a concentration of 2.0 nM of plasmin-alpha 2-antiplasmin complex in plasma, intra- and interassay variation coefficients were 4.2 and 5.5 percent respectively. In plasma samples of 25 control subjects the levels of plasmin-alpha 2-antiplasmin complex were below 1 nM. Extensive in vivo activation of the fibrinolytic system during thrombolytic therapy with streptokinase resulted in the generation of elevated levels of plasmin-alpha 2-antiplasmin complex up to 690 +/- 150 nM. No measurable levels of plasmin-alpha 2-antiplasmin complex were found in the plasma of 32 patients with acute deep vein thrombosis nor in the plasma of 11 patients with recurrent deep vein thrombosis. These findings indicate that plasmin-alpha 2-antiplasmin complex is generated during in vivo activation of the fibrinolytic system and that its assay may be useful to monitor thrombolytic therapy but not for the diagnosis of venous thrombosis.

Animals↗
PubMed1983

Butcher's knife wounds, are they really so contaminated?

The aerobic flora found in wounds caused by butcher's knives was compared with the flora in similar wounds caused by other sharp objects. Gram-positive bacteria predominated in the wounds caused by butcher's knives while the other cuts were colonised predominantly by Gram-negative flora. Identically low concentrations of colonising bacteria were found in both groups. The qualitative analysis provided no bacteriological argument for treating a wound from a butcher's knife as being more infected and therefore produced no contraindication for the primary reconstruction of damaged structures (i.e., tendons and nerves) together with skin closure in this type of injury.

Enterobacter↗
PubMed1976

Massive left atrial thrombus: a case report.

This case report describes a patient with aortic and mitral valvular disease who had a massive left atrial thrombus. The left atrial thrombus produced a disappearance of signs of mitral stenosis and a reversed pan diastolic mitral valve gradient. This gradient occurred in the absence of any diastolic mitral insufficiency and may have been due to artifactual lowering of the left atrial pressure by an organized left atrial clot.

Adult↗
PubMed1975

[Dose-response relationship of repeated injections of pentagastrin on the vagally innervated rat stomach in perfusion experiments].

In the perfusion model under urethane anesthesia Wistar rats were two times injected pentagastrin subcutaneously in a distance of 150 minutes in dose rates of 50, 100, 150, 200, 250 and 300 microgram/kg b. w. The results may be summarized as follows: 1. The dose of 200 microgram/kg b. w. of pentagastrin produced the maximal answer. Higher doses showed a diminished acid secretion. 2. The diminished effect of higher doses of gastrin may be caused by a hypothetical inhibitor which may be more effective after truncal vagotomy. 3. The repeated injection of pentagastrin did not show a significant difference of the answer. The second injection was given after the acid secretion has returned to the basal level. No tachyphylaxy was seen under these conditions.

Animals↗
PubMedDate not supplied

Estimation of incidence and prevalence of Parkinson's disease in the elderly using pharmacy records.

PURPOSE: We determined the prevalence and incidence of Parkinson's disease among persons aged 55 years and older in pharmacy records. METHODS: Data came from the PHARMO database which includes information on drug dispensing for all residents of six Dutch cities. We selected all persons aged 55 years and older who had used antiparkinsonian drugs, and calculated a chance for having Parkinson's disease with use of a previously validated logistic regression model. We used a cut-off of 0.5 (sensitivity 62%, positive predictive value 92%). Prevalence was estimated on the first Wednesday of October 1997, incidence on the first Wednesday of October 1993 until 1997. A patient was incident, if the first prescription for an anti-parkinsonian drug was dispensed at least 180 days after entry into PHARMO. Prevalence and incidence were standardized to the Netherlands population of 1 January 1998. The prevalence was adjusted for the sensitivity and positive predictive value of the model. RESULTS: The unadjusted prevalence (per 100,000) for those aged 55-64 years was 111, 65-74 years 598, 75-84 years 1551 and for persons aged 85 years and older 1847. The adjusted and standardized prevalence was 970 per 100,000 (95% confidence interval 869 to 1071). The incidence (per 100,000 person years) for persons aged 55-64 years was 12, 65-74 years 108, 75-84 years 257 and for persons aged 85 years and older 247. The standardized incidence was 109 per 100,000 person years (96 to 121). CONCLUSIONS: Prevalence and incidence were in range with the literature. Pharmacy records therefore seem to be a useful tool for continuous monitoring of incidence and prevalence of Parkinson's disease.

Aged↗
PubMedDate not supplied

Interactions between five candidate genes and antihypertensive drug therapy on blood pressure.

Despite the availability of effective antihypertensive drugs, there is a large variation in response to these drugs. This study investigates whether polymorphisms in the angiotensin converting enzyme (I/D), angiotensinogen (M235T), alpha-adducin (G460W), angiotensin II type 1 receptor (1166A/C), or G protein beta(3)-subunit (825C/T) gene modify the mean difference in blood pressure levels among diuretics, beta-blockers, or ACE-inhibitors users. Data were used from the Doetinchem Cohort Study, and blood pressure data were collected from GPs (1987-1997). A marginal generalized linear model (GEE) was used to assess the gene-drug interaction on the mean difference in systolic/diastolic blood pressure. In total, 625 hypertensive individuals were included with a total of 5262 measurements of blood pressure. Only the interaction between diuretic use and the GNB3 825C/T polymorphism was significant (C allele versus TT systolic blood pressure (SBP): 4.33 mmHg [95% CI: 0.14-8.54]). Thus, the mean SBP level among diuretic users may be modified by the GNB3 825C/T polymorphism.

Angiotensinogen↗
PubMedDate not supplied

The onset of rheumatoid arthritis in relation to pregnancy and childbirth.

It has been suggested that the onset of RA symptoms is reduced during pregnancy and increased in the postpartum period. In the present study symptom onset in relation to the pregnancy prior to disease onset was compared between 135 young RA patients with definite RA and 378 controls with soft tissue rheumatism or osteoarthritis. Two RA patients developed symptoms during pregnancy versus 9 controls (odds ratio OR = 0.64). In the 3 months postpartum 5 RA patients and 5 controls developed symptoms (OR = 3.37). These results show the same trend as those of previous studies, i.e. a decrease in the onset of RA during pregnancy and an increased onset of RA after delivery. These findings might be explained by a delayed clinical onset of RA that started during pregnancy, analogous with the ameliorating effect of pregnancy on the course of existing RA and the flare-up of disease activity in the postpartum period.

Adult↗