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Biomedical subjects

V Fidler

Publications and source records attributed to V Fidler.

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

Nanosecond fluorometry of the single tryptophan in cytochrome P-450e (P450IIB2).

Properties of the single tryptophan residue in rat liver microsomal phenobarbital-inducible cytochrome P-450e (P450IIB2) were studied by the nanosecond time-resolved fluorometry. The tryptophan fluorescence decay time was found to be 3.6 ns and it was not affected by the addition of substrate (perhydrophenanthrene). This result strongly indicates that the tryptophan residue is not a part of the substrate-binding site.

Animals↗
PubMed1989

Fat absorption in premature infants: the effect of lard and antibiotics.

Fat absorption of an adapted cow's milk formula was studied in a randomized controlled trial involving two groups of 18 premature infants (mean gestational age +/- SD: 33.0 +/- 2.9 weeks, range 26.5-37.5 weeks). The triglyceride configuration was modified by the use of lard. This modification did not improve the absorption of fat or energy. Also no difference in serum concentrations of cholesterol and triglycerides was found. Growth velocity during the study was similar in both groups. Detailed analysis of the data revealed that in infants who received (parenterally) antibiotics (mainly ampicillin and netilmicin) a higher coefficient of fat absorption (+20%, P less than 0.01) and of energy absorption (+8%, P = 0.03) was found. Based on these results, we find no support for the use of lard in adapted cow's milk infant formulas to improve fat absorption. In studies of fat and energy absorption the effects of antibiotics have to be taken into account.

Anti-Bacterial Agents↗
PubMed1989

Effect of chlorhexidine rinsing on the oropharyngeal ecology in patients with head and neck cancer who have irradiation mucositis.

Oral flora is thought to contribute to irradiation mucositis in patients with head and neck cancer. Neglect of oral hygienic care may also contribute to mucositis. The purpose of this prospective, randomized, placebo-controlled, double-blind study was to evaluate the effect of chlorhexidine 0.1% mouthrinses on oral flora and irradiation mucositis. This study included 30 patients with head and neck cancer who had comparable irradiation portals. One group (N = 15) rinsed four times daily with chlorhexidine 0.1%, the other group (N = 15) with a placebo. The oral flora was cultured (oral washing technique) twice before and three times per week during the period of radiotherapy. On the same days, the severity of mucositis was determined. The colonization index of viridans streptococci was significantly reduced only after 5 weeks of chlorhexidine 0.1% treatment. The colonization patterns of Candida species, Streptococcus faecalis, staphylococci, and Enterobacteriaceae, Pseudomonadaceae, and Acinetobacter species were not influenced by 5 weeks of use of chlorhexidine rinses when compared with the placebo. No differences were seen between the two study groups in the development and severity of mucositis. In conclusion, suppression of oral flora and a lowering of the severity of mucositis by means of disinfecting mouthrinses were not successful.

Adult↗
PubMed1989

In vivo study on the prevention of postradiation caries.

Postradiation caries is usually prevented by the application of topical fluorides (F) at high concentrations. The aim of this study was to develop an optimal preventive program for postradiation caries by evaluating the effects of F concentration and application procedures in subjects with radiation-related xerostomia. Six ground enamel slabs were mounted on each side of the lower denture of each of 7 xerostomia patients. Four procedures were used: no F exposure (control), neutral F gel applied every 2nd day or weekly, and a daily rinse with a F mouthwash for a period of 6 weeks. The enamel slabs were analyzed at weekly intervals by scanning optical monitoring, longitudinal microradiography, and scanning electron microscopy. In addition, hardness measurements were performed on the slabs. F analyses of the enamel slabs were done prior to their insertion in the appliances and after 6 weeks of intraoral exposure. In the control experiments severe demineralization of enamel occurred within 6 weeks. Application of F gel or the use of the F mouthrinse resulted in a significant inhibition of the demineralization process. Of the procedures evaluated, F gel applied every 2nd day was the most effective in preventing the onset of postradiation caries.

Aged↗
PubMed1988

Instrumental variables in the evaluation of diagnostic test procedures when the true disease state is unknown.

We explore the estimation of sensitivity and specificity of diagnostic tests when the true disease state is unknown. Instrumental variables which subdivide the patient population are used. A logistic model, relating these instrumental variables to the (unknown) true disease state is proposed. It is shown that this procedure allows the goodness-of-fit to the resulting model to be tested.

Dapsone↗
PubMed1988

Red cell aggregation during normal pregnancy.

Red cell aggregation (RCA) is responsible for the increase in whole blood viscosity at lower shear rates. RCA depends on the concentrations of red cells and plasma proteins with a high molecular weight and a large and asymmetrical spatial structure such as fibrinogen, immunoglobulin M and alpha 2-macroglobulin. During normal pregnancy, changes occur in all these concentrations. In a prospective study these changes and their influence on the resulting RCA were investigated in 24 healthy women with normal pregnancies. RCA was determined by light reflection measurement (syllectometry). RCA considerably increased during normal pregnancy in spite of the physiological haemodilution. The aggregation half time, used as a measure for RCA, decreased from an average non-pregnant value of 5.6 s to 3.3 s at 37 weeks. Multiple regression analysis showed that the increase in RCA could be mainly attributed to the raised fibrinogen concentration. However, at 37 weeks other factors, in addition to fibrinogen, contribute significantly to the increase in RCA.

Erythrocyte Aggregation↗
PubMed1987

Whole blood viscosity during normal pregnancy.

In a serial study the changes in whole blood viscosity at different shear rates and its major determinants were determined in 24 healthy women with normal pregnancies. Whole blood viscosity and plasma viscosity were measured with a rotational viscometer. Red cell aggregation was measured by syllectometry. During normal pregnancy we found a decrease in whole blood viscosity at all shear rates until 29 weeks gestation, followed by a smaller increase between 30 and 37 weeks, which was most pronounced at higher shear rates, especially in nulliparae. The changes in whole blood viscosity were to a great extent determined by the changes in haematocrit and plasma viscosity. Haematocrit was more important for whole blood viscosity at lower shear rates, while plasma viscosity had more influence on high shear blood viscosity. The continuous increase in red cell aggregation had no demonstrable influence on low shear blood viscosity as measured in vitro in a rotational viscometer.

Blood Viscosity↗
PubMed1986

Detection of electrocardiographically imperceptible ventricular pre-excitation by phase imaging.

The sequence of ventricular contraction was studied by radionuclide phase imaging in 25 patients with Wolff-Parkinson-White syndrome. The studies were performed when no signs of precontraction were present in the electrocardiogram; in these cases pre-excitation was either intermittent or suppressable by injection of ajmaline. In 11 of the 16 patients with free wall accessory pathways, precontraction could be detected in spite of electrocardiographically absent pre-excitation. Discrete precontraction was seen also in 2 of the 9 patients with paraseptal accessory pathways. We conclude that antegrade conduction through the accessory pathway does not need to be completely blocked if signs of pre-excitation are absent on the electrocardiogram, and that phase imaging is, at least in some patients (especially those with free wall accessory pathways), a more sensitive technique for detection of pre-excitation (precontraction) than the electrocardiogram.

Electrocardiography↗
PubMed1986

Artificial periodontal defects and frequency of tooth brushing in beagle dogs (I). Clinical findings after creation of the defects.

This investigation was designed to determine the influence of different frequencies of tooth brushing on artificial periodontal defects in the beagle dog shortly after creation. In 12 beagle dogs, periodontal defects were created using elastic bands placed in the sulci below the gingival margin after having cut the dento-gingival fibres to the level of the alveolar bone. This active phase of creating defects lasted for 6 weeks. 6 premolars in the lower jaw were used (2P2, 3P3, 4P4). After removal of the elastic bands, the 12 dogs were distributed into 3 groups of 4 dogs each. Each group was brushed with a certain frequency, i.e., 7 times, 3 times or once a week. Plaque index, gingival index and probing depth, using a constant force probe, were assessed interproximally. The experiment lasted for 24 weeks. For hypothesis testing, a brushing effect was calculated for each dog. Furthermore, an analysis was performed based on the absolute scores at week 24. From the statistical analysis, it was concluded that in artificially-induced periodontal defects in beagle dogs immediately after creation, brushing 7 times a week is superior to brushing 3 times a week to establish and maintain gingival health.

Animals↗
PubMed1986

Diagnostic significance of nailfold capillary patterns in patients with Raynaud's phenomenon. An analysis of patterns discriminating patients with and without connective tissue disease.

Nailfold capillary patterns were systematically evaluated in 51 controls and 107 patients with Raynaud's phenomenon (RP) by 2 observers. Fifty patients had primary RP, 18 RP with minor signs of connective tissue disease, and 39 secondary RP (scleroderma, CREST syndrome or mixed connective tissue disease [MCTD]). Nailfolds of all 10 fingers were photographed and blindly evaluated. Qualitative and quantitative scoring of patterns was reproducible. The 4th finger showed the fewest nonevaluable photomicrographs and best distinguished primary from secondary RP. Capillary morphology in primary RP did not differ from controls. A decrease in capillary loops best distinguished primary from secondary RP. Addition of the scores for bushy patterns, extravasates, or giant loops led to better discrimination. No item allowed distinction between different connective tissue diseases. The number of enlarged loops was inversely related to the total number of capillary loops (r = 0.55; p less than 0.01).

Adult↗
PubMed1985

Wolff-Parkinson-White syndrome type B and left bundle-branch block: electrophysiologic and radionuclide study.

Coinciding left bundle-branch block and Wolff-Parkinson-White syndrome type B, a very rare electrocardiographic occurrence, was found in a patient with dilated cardiomyopathy. Electrophysiologic study revealed eccentric retrograde atrial activation during ventricular pacing, suggesting right-sided accessory pathway. At programmed atrial pacing, effective refractory period of the accessory pathway was 310 ms; at shorter pacing coupling intervals, normal atrioventricular conduction with left bundle-branch block was seen. Left bundle-branch block was seen also with His bundle pacing. Radionuclide phase imaging demonstrated right ventricular phase advance and left ventricular phase delay; both right and left ventricular phase images revealed broad phase distribution histograms. Combined electrophysiologic and radionuclide investigations are useful to disclose complex conduction abnormalities and their mechanical correlates.

Aged↗
PubMed1985

The relation between umbilical pH values and neonatal neurological morbidity in full term appropriate-for-dates infants.

The relationship of umbilical cord pH with the neonatal neurological condition was investigated in a group of 805 appropriate-for-dates (AFD) infants, delivered vaginally at term, and in a subgroup of 205 infants born after uncomplicated pregnancy and delivery ('low-risk' group). The results of the neonatal neurological examination were expressed in a neonatal neurological optimality score (NNOS) and in a neurological classification (normal, suspect and abnormal). In both study groups a significant relation between umbilical arterial pH (pHua) and the difference between maternal venous pH and pHua (delta pHm-ua) on the one hand and neurologically suspect infants and NNOS on the other hand, was found. The percentages of explained variance in NNOS, however, were very low (for delta pH, 1 and 4% in the total and low-risk group respectively). Neurological abnormality was not related to acidaemia at birth. Because of the specific relation between maternal and umbilical pH, delta pH is a less reliable indicator of fetal condition in cases of maternal alkalosis or acidosis. The use of a delta pH corrected with the help of a maternal-fetal pH nomogram, however, only slightly improved the relation with neurological morbidity. It is concluded, that in AFD term infants acidaemia at birth is only slightly related to neonatal neurological morbidity.

Asphyxia Neonatorum↗
PubMed1985

Serum beta 2-microglobulin: a real improvement in the management of multiple myeloma?

Beta 2-microglobulin (B2-m) determinations in serum have recently been introduced as a method of stratifying patients suffering from multiple myeloma. Conflicting results from several studies prompted us to study retrospectively the correlation of B2-m with presenting features and disease stage, as well as the prognostic value of B2-m, in 87 myeloma patients. Significant correlations were found between B2-m and presenting features such as haemoglobin level, serum calcium level and total body myeloma cell mass. The strongest correlation existed between B2-m and serum creatinine (r = 0.68). B2-m did not discriminate between the different disease stages as defined by Durie and Salmon, nor between myeloma Stage IA and monoclonal gammopathy of undetermined significance (MGUS). Considered alone, B2-m was found to have prognostic value in terms of survival. This correlation disappeared after correction for serum creatinine level and tumour load (multivariate analysis). Furthermore, changes in tumour load during therapy were not reflected in changes in B2-m levels, thereby rendering B2-m levels invalid as tumour marker. Our findings indicate no value for B2-m determinations in the staging and follow-up of myeloma patients.

Creatinine↗
PubMed1985

Multiple accessory pathways: a combined electrophysiological and radionuclide study.

Electrophysiological study in a patient with Wolff-Parkinson-White syndrome revealed multiple accessory pathways: Kent bundle and Mahaim nodoventricular and fasciculoventricular fibers. Radionuclide phase imaging disclosed two distinct ventricular activation sequences during sinus rhythm or slow atrial pacing and during fast atrial pacing. The third activation pattern could be recorded after injection of ajmaline, which abolished signs of preexcitation in the electrocardiogram. Phase image in combination with pacing and pharmacological interventions can, at least in some cases, detect complex preexcitation syndromes noninvasively.

Adult↗
PubMed1984

Oropharyngeal flora as a source of bacteria colonizing the lower airways in patients on artificial ventilation.

During 1 year 27 patients admitted to the respiratory intensive care unit were monitored bacteriologically for a minimum of 10 days (mean: 26.7 days). Oropharyngeal swabs and tracheal aspirates were qualitatively and semi-quantitatively cultured twice weekly. A correlation between oropharyngeal and tracheal flora was found: once a bacterial species colonized the oropharyngeal cavity in high numbers, the identical microorganism was frequently isolated (greater than 50%) from the lower respiratory tract. Six of the 27 patients acquired an infection of the lower airways in the respiratory intensive care unit. The bacteria involved belonged to the patients oropharyngeal flora: S. aureus, Enterobacteriaceae and Pseudomonadaceae. As a result of this study showing the oropharynx to be the source of lower airway colonization/infection, a policy for infection prevention has been outlined. This policy is based on the concept of source elimination by means of oropharyngeal decontamination.

Adolescent↗