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Biomedical subjects

W Jansen

Publications and source records attributed to W Jansen.

At least 73 records · Page 4Linked to original sources
PubMed1989

Specific gene probe for detection of biotyped and serotyped Listeria strains.

A total of 284 strains of Listeria, including all known serovars and biovars together with Listeria grayi and Listeria murrayi, were biotyped and serotyped. Biotyping and serotyping could be done in 2 days. A gene probe encoding a delayed hypersensitivity factor (DTH) was used in the detection of pathogenic biotypes and serotypes of the tested strains. The gene was found in all 117 tested Listeria monocytogenes strains of serogroups 1/2a, 1/2b, 1/2c, 3a, 3b, 3c, 4c, 4d, 4e, 4ab, and 7. It was also present in Listeria ivanovii. Of 78 L. monocytogenes strains of serogroup 4b, 77 strains contained the gene, whereas it was absent in all 10 tested L. monocytogenes strains of serogroup 4a. Furthermore, the gene was absent in Listeria seeligeri, L. grayi, L. murrayi, and L. innocua of serogroups 3c, 4b, and 6a and in L. welshimeri of serogroups 1/2b, 3b, 6a, and 6b. Since L. monocytogenes and L. ivanovii are the only two biotypes of the genus Listeria considered pathogens, the data obtained indicate that the DNA probe tested may be a useful tool in the detection of virulent Listeria isolates in clinical, environmental, and food samples.

Bacterial Typing Techniques↗
PubMed1989

[Lack of tolerance development in interval therapy with 50 mg isosorbide-5-nitrate retard (Elantan long)].

Fluctuating mononitrate plasma levels in the course of 24 h are a prerequisite for prevention of nitrate tolerance in patients with angina pectoris undergoing longterm treatment. In 12 patients with angiographically proven coronary artery disease (54 +/- 7 years) effects of 50 mg Isosorbide-5-mononitrate (IS-5-MN) in a slow-release (SR) formulation on hemodynamics and exercise tolerance were evaluated after a first dose and at the end of a 1-week treatment period with 50 mg given once-daily. 1 and 2 h after medication mean pulmonary artery pressure (PAP) at rest was reduced by 30% (p less than 0.001) and 25% (p less than 0.01 respectively. During submaximal bicycle exercise (50 W, 3 min) PAP was significantly reduced by IS-5-MN by 35% (1 and 2 h after medication). At the end of exercise (discontinuation), drug-induced reductions of PAP were 19% (1 h) and 21% (2 h) (p less than 0.05), respectively. IS-5-MN led to a marked increase of exercise capacity (base-line: 396 +/- 119 W x min); 1 h: 646 +/- 153 W x min (p less than 0.01). At stress testing 2, 4 and 10 h post medication improvements were 67% (p less than 0.01), 49% (p less than 0.01) and 28% (p less than 0.01), respectively. 24 h after medication baseline values were reached again. After a 1-week treatment with 50 mg IS-5-MN SR daily, beneficial effects of the drug on hemodynamics and working capacity could be demonstrated. Again, significant effects could be shown up to 10 h after drug administration. Thus, IS-5-MN SR administered once daily proved effective in intermediate-term treatment of patients with coronary artery disease with regard to hemodynamics and exercise capacity.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1989

Construction of the diagnostic encyclopedia workstation. Computerizing pathology for the pathologist.

The combination of a personal computer and a laser-vision disc player is an adroit tool for storing and retrieving textual information in combination with pictorial information. This paper describes such a system (a "diagnostic encyclopedia workstation"), which provides information to the pathologist engaged in daily diagnostic practice. The system contains a considerable amount of descriptive textual information that might be useful in making diagnoses in histopathology, along with many illustrations; the text is presented in a natural language (English). The descriptive information is divided into 18 categories, including such topics as histology, macroscopy, immunopathology and clinical data; each topic has a separate display in the system. Also present are two types of "decision rules" for making diagnoses (confirmative criteria for a diagnosis under consideration and exclusive criteria for many other diagnoses) and a classifying structure. The present version of this system contains information on about 100 diagnoses in ovarian pathology, illustrated with about 3,000 color slides from about 140 cases. The information and pictures are immediately available. Further characteristics of this system are its flexibility, accessibility and user friendliness; it has been structured so that components of artificial intelligence may be added later.

Artificial Intelligence↗
PubMed1988

Acute effect of various doses of isosorbide-5-mononitrate on hemodynamic and exercise performance in coronary artery disease.

The optimal dose of nitrates is still controversial, as chronic usage of too high a dose may result in a decrease in vascular response. The dose should be determined to reduce preload acutely, and not to decrease the activity during chronic therapy. To determine this dose, 50 patients with angiographically confirmed coronary artery disease were studied. The effects on heart rate and mean systemic and pulmonary arterial pressures at rest and during exercise, and work capacity and duration were measured. The patients were classified into 5 groups, receiving placebo or isosorbide-5-mononitrate, 5, 10, 20 and 50 mg, respectively, as a single oral dose. Placebo had no effect on the measured parameters. All doses of isosorbide-5-mononitrate reduced mean pulmonary arterial pressure: 10 mg--by 16% at rest and 24% during exercise; 20 mg--24% and 34%, respectively (a near maximal effect); and 50 mg--27% and 38%. Similar results were found also for work capacity: 10 mg increased work capacity by 33%; 20 mg--79%; and 50 mg--56%. Thus, the therapeutically optimal single dose is about 20 mg. Higher doses produce no additional benefit and increase the risk for tolerance development.

Adult↗
PubMed1988

[Evaluation of ST-segment analysis in long-term ECG].

The accuracy of ST-segment analysis by means of the Marquette-Laser-Holter system was compared with conventional ECG registration during ergometry. In 26 patients with angiographically confirmed coronary heart disease conventional chest leads and long-term ECGs were recorded simultaneously during standardized exercise. Simultaneously registered ST-segments in V5 and Holter CM5 were compared, with the results correlating well (r = 0.91) for any recorded abnormal repolarizations.

Adult↗
PubMed1988

Primary malignant mucosal tumours of the small bowel.

Three cases of primary malignant tumours in the small bowel are presented. The authors discuss the clinical symptoms of these patients and describe the radiological picture. Adenocarcinoma most frequently occurs in the proximal small bowel. Radiologists should be aware of the dominant site of occurrence of these tumors when performing a small bowel investigation, because lesions in the jejunum may easily be overlooked due to superposition.

Adenocarcinoma↗
PubMed1988

Cell proliferation in the murine epidermis and subcutaneous vascular endothelium after hyperthermia.

The skin of mouse legs was exposed to 44 degrees C hyperthermia using a thermostatically controlled waterbath. Treatment at 44 degrees C, for 15 or 30 min, led to oedema in the dermis immediately after treatment and to an infiltration by neutrophils within 7 h. The oedema disappeared in 2 days. Treatment for 60 min at 44 degrees C led to subepidermal blistering and as a result of this a considerable area of the tissue became necrotic 4 days after treatment. A repair reaction followed, and 3 weeks after heating for 60 min at 44 degrees C the epithelium was again completely or almost completely covering the underlying tissue. Shortly (7 h) after 15 or 30 min at 44 degrees C an increase was observed in the number of basal cells in the epithelium incorporating [3H]thymidine. This increase declined slowly with time: 3 weeks after treatment the number of labelled basal cells was not significantly different from that in untreated skin. Shortly after 60 min at 44 degrees C some basal cells of the epidermis still incorporated [3H]thymidine. The labelling index dropped to near-zero at day 2 after 60 min at 44 degrees C. Thereafter repopulation started and in the areas next to the granulation tissue the labelling index of basal cells reached values close to 100 per cent, 2 or 3 weeks after treatment. Treatment for 15 min at 44 degrees C did not lead to a stimulation of the proliferation of subcutaneous endothelial cells. Both 30 min and 60 min at 44 degrees C led to a greatly enhanced proportion of labelled subcutaneous endothelial cells after 2 days and 4 weeks, respectively (labelling index between 35 and 40 per cent). After this peak value the labelling index declined rapidly. However, in granulation tissue it remained high for about 10 days after the peak on day 4. The stimulated proliferation of subcutaneous endothelial cells after heating for 30 and 60 min at 44 degrees C correlated well with the finding that these heat treatments, given after or shortly before X-irradiation, led to a greatly reduced (X-ray-induced) tumour bed effect.

Animals↗
PubMed1988

Slow and incomplete histological and functional recovery in adult gluten sensitive enteropathy.

To assess the course of recovery of gluten sensitive enteropathy in adults, histological and functional recovery was studied in 22 patients, aged 20-79 years. Biopsy specimens taken at the time of diagnosis were studied in 20; after adhering to a gluten free diet for nine to 19 (mean 14) months in 14; and after adhering to the same diet for 24-48 (mean 34) months in 10 patients. Histological recovery was assessed morphometrically in the proximal jejunum. Mucosal linings significantly improved over time, but did not completely return to normal with a gluten free diet: at diagnosis the surface: volume ratio was 22% of normal, increasing to 48% and 66% after nine to 19 and 24-48 months, respectively, of a gluten free diet. Disaccharidase activities progressively increased. After 24-48 months maltase, sucrase, and isomaltase had returned to normal in the proximal jejunum; they were still significantly decreased in the distal duodenum. Duodenal and jejunal lactase activities were both below normal after 24 to 48 months. It is concluded that recovery of the intestinal mucosa of adults with gluten sensitive enteropathy during a gluten free diet continues beyond nine to 19 months and is still incomplete after two to four years. The recovery of disaccharidase activities extends from the distal to the proximal part of the small intestine, and is aligned to histological recovery.

Adult↗
PubMed1987

Coexistence for systems governed by difference equations of Lotka-Volterra type.

The question of the long term survival of species in models governed by Lotka-Volterra difference equations is considered. The criterion used is the biologically realistic one of permanence, that is populations with all initial values positive must eventually all become greater than some fixed positive number. We show that in spite of the complex dynamics associated even with the simplest of such systems, it is possible to obtain readily applicable criteria for permanence in a wide range of cases.

Animals↗
PubMed1987

Acute and chronic effects of molsidomine on pulmonary artery pressure and work capacity in patients with coronary heart disease.

To test the clinically supposed development of tolerance during chronic molsidomine therapy we studied a total of 11 patients with angiographically-proven coronary heart disease at rest and during ergometric exercise (supine position; submaximal, i.e. 50 W for 3 min, and maximal exercise). Pulmonary arterial pressure (PAPmean, floating catheter), arterial blood pressure (RR, cuff method), work capacity (W x min) and duration of exercise loading (sec) were measured at rest and on exercise before and during chronic (4 weeks) oral therapy with 3 x 4 mg day-1 of molsidomine. Acute administration of 4 mg molsidomine reduced the mean arterial resting pressure by 12% and under submaximal exercise loading by 8%. After molsidomine, the PAPmean was reduced by 35% at rest; following a period of treatment of 4 weeks no significant decrease in efficacy could be discerned (PAPmean reduction by 31%). Under submaximal and maximal exercise the PAPmean dropped by 44% and 37%, respectively (35.5 +/- 6.7 cf. 19.9 +/- 4.5 mmHg; 39.2 +/- 6.5 cf. 24.8 +/- 7.0 mmHg), whilst simultaneously the work capacity increased by 93% (281 +/- 108 cf. 545 +/- 254 W x min). After 4 weeks treatment with 12 mg day-1 of molsidomine, the PAPmean of 22.4 +/- 6.6 mmHg and 30.1 +/- 9.9 mmHg under identical exercise loading conditions, remained significantly below the exercise load value prior to the onset of medication. The molsidomine-induced increase in the exercise tolerance was maintained throughout the long-term medication (537 +/- 268 W x min). With a four-week treatment with daily doses of molsidomine there was a persistent effect on the pulmonary arterial pressure and the work capacity. Thus development of tolerance during high dose, long-term molsidomine therapy is not to be expected.

Adult↗
PubMed1987

MRI of normal or cancerous laryngeal cartilages: histopathologic correlation.

MRI appearances of laryngeal cartilages, normal or invaded by cancer, are still relatively unfamiliar to most clinicians. Twelve primary laryngeal tumors out of a series of 65 patients which have been investigated by MRI were examined postoperatively by macroscopic and microscopic sectioning of the surgical specimens. Images were obtained with a 0.6 Tesla superconductive system using a solenoid surface coil. The authors emphasize the value of a combined use of T1-weighted and balanced (relatively T2-weighted images with still T1-characteristics) Spin Echo images. T1-weighted images permit differentiation between pathological and normal bone marrow. Balanced images allow separation between nonossified cartilage and tumor tissue. MRI is an additional tool in the diagnostic workup of cartilage invasion by tumor.

Aged↗