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Biomedical subjects

V Fidler

Publications and source records attributed to V Fidler.

At least 19 recordsLinked to original sources
PubMed1992

Colonization of burns and the duration of hospital stay of severely burned patients.

In a retrospective study the influence of several factors on the length of hospital stay of severely burned patients (at least 24% total body surface area) has been investigated. The influence of these factors was studied by means of the Cox model survival analysis with time-varying covariates. Seventy-one patients were included in this study. The mean age was 32 years (range 1-82 years), the mean total body surface area burned 40% (range 24-80%) and the mean full-thickness area burned 32% (range 10-70%). The length of hospital stay was positively correlated with the extent of the burned area and with the age of the patient. Wound colonization with Enterobacteriaceae or with a combination of Pseudomonas spp. and Staphylococcus aureus was also associated with a prolonged stay in hospital.

Adolescent↗
PubMed1992

Study of myocardial regional wall motion parameter's accuracy by software perfusion phantom.

Gated perfusion myocardial scintigraphy permits simultaneous evaluation of perfusion as well as regional contractile function of the left ventricle. Fourier analysis of regional myocardial spatial movement with respect to the myocardial geometric centre gives circular amplitude and phase profiles of ventricular contraction, in addition to regional maximum activity that represents an index of perfusion. To introduce such combined perfusion-contraction analysis the accuracy of the indices mentioned above should be evaluated for different doses of radioactivity typically administered to a patient. A mathematical software phantom, consisting of a half circularly profiled ring activity embedded in uniform background activity and noise generated by a Poisson-shaped random number generator, was constructed and used for this purpose. A 64 x 64 matrix and sequence of 16 frames per study was used. The maximum number of counts per pixel ranged from 10 to 100, simulating low count thallium and high count rate Tc-MIBI-gated studies. The relative standard error analysis (R.S.E.) with a 95.5% confidence level for a thallium type of 10 counts per pixel study exceeded 11%, while it reached acceptable values below 3% for studies with 60 and more counts per pixel. These results indicate that high count rate gated technetium-MIBI myocardial perfusion studies could also be used for reliable left ventricular regional wall motion evaluation.

Gated Blood-Pool Imaging↗
PubMed1992

Glomerular macrophage modulation affects mesangial expansion in the rat after renal ablation.

Recent studies have provided evidence for the involvement of macrophages (m phi) in various types of human and experimental glomerular disease. The aim of the present study was to examine the effect of m phi depletion on glomerular injury after 3/4 renal ablation in the rat. This "remnant kidney" model is a widely used experimental model of focal and segmental glomerulosclerosis. Sustained glomerular m phi depletion was induced in remnant kidney rats by a regimen of sublethal triple systemic X-irradiation with shielding of the kidney remnants. Groups of 8 X-irradiated and 8 non-irradiated rats were studied at 5, 9, and 13 weeks after renal ablation. X-irradiated rats showed severe peripheral blood leukopenia at 5 and 9 weeks which had normalized at 13 weeks. The number of remnant glomerular m phi (immunohistochemistry with the monoclonal antibody ED1) in X-irradiated rats at 5 weeks was significantly lower when compared to non-irradiated remnant kidney rats. A rebound effect occurred at 9 and 13 weeks with increased m phi in remnant glomeruli of X-irradiated rats. Light microscopic examination disclosed significantly lower semiquantitative scores for mesangial cellularity and mesangial matrix expansion in remnant glomeruli of X-irradiated rats at 5 weeks when compared to non-irradiated remnant kidney rats. Mesangial matrix expansion had increased in X-irradiated rats at 9 and 13 weeks after ablation coincident with elevated glomerular m phi at these intervals. Multiple linear regression analysis indicated a highly significant contribution of m phi to the best fitting regression model predicting mesangial matrix expansion (multiple r2 = 0.81). In conclusion, these data provide evidence for a contributory role of m phi in the evolution of glomerular injury in the rat after renal ablation.

Animals↗
PubMed1991

Nanosecond fluorescence of tryptophans in cytochrome P-450scc (CYP11A1): effect of substrate binding.

Fluorescence of eight tryptophan residues in cytochrome P-450scc with bound endogenous cholesterol could be fitted with a two component model: a single exponential and a "top-hat" distribution of lifetimes as the second component. The short-lived component (tau 1 about 700 ps) does not change significantly upon binding of substrate (22R-hydroxycholesterol). The parameters of the long-lived component (central lifetime tau m about 3.4 ns) change upon binding of carbon monoxide and substrate. 22R-hydroxycholesterol binding broadens the distribution of the long-lived component; that is the heterogeneity of the Trp environment is increased when this substrate displaces the endogenous cholesterol.

Adrenal Glands↗
PubMed1991

Effect of selective elimination of the oral flora on mucositis in irradiated head and neck cancer patients.

Recently it has been reported that chlorhexidine 0.1% rinsing was not successful in eradication of gram-negative bacilli in patients who have head and neck cancer. These bacilli could play a role in irradiation mucositis. This study reports the effect of lozenges containing 2 mg polymyxin E, 1.8 mg tobramycin, and 10 mg amphotericin B qid on the oropharyngeal flora in 15 irradiated head and neck cancer patients. The results were compared with those of a previous study in two groups of 15 patients comparing chlorhexidine rinsing with placebo. In all patients using lozenges, eradication of gram-negative bacilli and yeasts was achieved within 3 weeks. A significant increase of enterococci was found. Mucositis was significantly reduced compared with the previous two groups. All patients showed erythema only, whereas 80% of both the placebo and chlorhexidine rinsing patients suffered from severe mucositis, with signs of pseudomembranes developing from the third week of conventional irradiation protocol. The effect of selective elimination of gram-negative bacilli from the oropharynx and the prevention of severe mucositis may be explained by the eradication of these bacteria and/or neutralization of salivary endotoxin, released by gram-negative bacilli, mediating the inflammatory processes.

Adolescent↗
PubMed1991

[Comparative animal experiment studies of the effect of exogenous collagen on healing of a deep skin wound].

The high number of available wound dressings as well as the scientific reports about this topic indicates that the problem of an ideal wound dressing material is not jet solved. In the last 30 years lot of scientific reports about collagen as wound covering has been published. The positive effect of collagen by this application on a wound is well-known. We investigated the effect of a collagen sponge on healing of full thickness wound in rats. The animals were divided in two control and two experimental groups. In the control groups there were air exposed wounds as well as wounds covered with paraffin gauze. In the experimental groups the wounds were covered with natural reconstituted collagen sponge as well as with chemically prepared sponge. All results were compared. The wounds with collagen sponge covering healed significantly faster. Also the quality of the wound healing was better in the experimental groups.

Animals↗
PubMed1991

Vibration perception threshold, complaints and sensory examination in diabetic patients.

The vibration perception threshold (VPT) was investigated by means of a biothesiometer among 40 patients with insulin dependent diabetes mellitus. The age as well as the duration of the disease affected the VPT. However, a correlation between the VPT and the rate of metabolic control measured through the glycolysed Hb (HbAlc) could not be demonstrated. In early stages abnormalities were already detectable in the feet. The VPT was elevated in 13 of 20 patients with sensory complaints and in 4 of 20 patients without complaints. Routine neurological examinations such as light touch and pinprick sensation were less sensitive to diagnose neuropathy. In detecting early signs of diabetic neuropathy in an outpatient population the determination of the VPT is a sensitive tool.

Adolescent↗
PubMed1991

Hand-held myometry: reference values.

In thirteen major muscle groups of 50 healthy females and 50 males, aged 20-60 years, maximum voluntary contraction was measured with a hand-held dynamometer. The intrasession variation, the left-right variation, and the fifth and fiftieth centile values were calculated. The ratio of two observations within one session ranged from 0.85 to 1.18 and the ratio of left to right ranged from 0.82 to 1.22 (95% reference limits). In 20 volunteers the repeatability was tested after one week. The ratio of averages of three measurements in two successive weeks ranged from 0.82 to 1.23 (95% reference limits). There were only small differences between muscle groups concerning these ratios. A significant relation with age and weight/Quetelet Index could be demonstrated in some muscle groups. The mean strength of females is approximately two thirds of the strength of males. The data may be useful as reference values in the application of hand-held myometry.

Adult↗
PubMed1991

Computer-assisted analysis of normal second trimester fetal heart rate patterns.

A software package for computer-assisted analysis of antenatal fetal heart rate (FHR) patterns has been commercially available from 1989. Reference ranges for the third trimester of pregnancy have been established. In order to obtain reference values for the second trimester, one hour FHR recordings were made between 20 and 29 weeks gestation in 77 women with uncomplicated pregnancies. There was a significant increase of (medium term) FHR variation and of the number of accelerations from 20 to 29 weeks (r = 0.48, p less than 0.01 and r = 0.34, p less than 0.01 respectively). The lower limit of normal FHR variation (mean--2 SD's) increased from 18 msec at 20 weeks to 28 msec at 28 weeks. Furthermore, a 30 minute recording appeared to be sufficient to obtain a reliable impression of FHR variation. Short term FHR variation, a measure of FHR variation that facilitates the identification of sinusoidal FHR patterns, also increased significantly between 20 and 29 weeks (r = 0.61, p less than 0.01). Delerations (greater than 20 beats/min and greater than or equal to 30 seconds) were present in 54% of the recordings and are a more or less common phenomenon at this age. It is concluded that during the second trimester FHR variation differs considerably from that in the third trimester. This should be taken into account in the interpretation of second trimester FHR records.

Cardiotocography↗
PubMed1991

Determinants of focal and segmental glomerulosclerosis in the rat after renal ablation. Evidence for involvement of macrophages and lipids.

The present study was undertaken to estimate the relative impact of a number of clinicopathologic and glomerular structural changes on severity and composition of focal and segmental glomerular sclerosis (FGS) in rats subjected to renal ablation. Groups of eight 1 1/2-nephrectomized (Nx) and sham-operated (Sh) male Wistar rats were studied at intervals of 2, 4, 8, 12, and 16 weeks. At sacrifice, kidney tissue was embedded in glycolmethacrylate to achieve optimal morphology for light microscopy, immunohistochemistry, and morphometry. FGS lesions were defined by the presence of focal and segmental glomerular scarring and collapse of the glomerular tuft with increased mesangial cellularity (MC), mesangial matrix expansion (MME), and adhesions between the tuft and Bowman's capsule (Adh). The severity of FGS and extent of MC, MME, and Adh was graded seimquantitatively to establish an injury score. The dependence of FGS injury score and of the scores of MC, MME, and Adh on a variety of clinicopathologic and glomerular structural alterations, taking account of possible correlations among them, was estimated with partial correlation and multiple linear regression analysis. The structural parameters included hyalinosis (H, PAS stain), glomerular lipid deposits (GLD, Oil Red O stain), glomerular volume expansion (GVE, morphometry), glomerular cellular proliferation (labeling of S-phase cells by 5 bromo-2'-deoxyuridine, BrdU)--and glomerular influx of macrophages (m phi), T cells, natural killer cells, and granulocytes (immunohistochemistry with mouse monoclonal antibodies). The clinicopathologic variables were urinary protein excretion (UP), fasting serum cholesterol levels (FChol), body weight (BW), total wet kidney weight (KW), heart weight (HW), and systolic blood pressure (SBP). The best fitting linear regression model, explaining 91% of the total variation of the FGS injury score (multiple r2 = 0.91), included UP as the main clinical, and H as the main structural variable. MC was explained best by BrdU incorporation (multiple r2 = 0.77). The optimal regression model describing MME contained the variables H, m phi, and FChol (multiple r2 = 0.84). The extent of Adh formation was optimally described by UP, m phi, and FChol (multiple r2 = .88). In conclusion, although none of these statistically significant associations indicate causal relationships, they identify - in addition to UP, H, and cellular proliferation - FChol as a major clinical determinant and glomerular m phi influx as a major structural alteration associated with FGS in the setting of renal ablation.(ABSTRACT TRUNCATED AT 400 WORDS)

Animals↗
PubMed1990

Chlorhexidine inactivation by saliva.

Chlorhexidine mouth rinsing is commonly used for oral flora reduction. Indigenous microorganisms (viridans streptococci) are significantly suppressed, while "hospital-acquired" gram-negative bacilli are not affected in vivo. To explain the discrepancies between good in vitro and poor in vivo activity of chlorhexidine, minimum bactericidal concentration values for 120 isolates were studied by means of a standard dilution method in fresh whole saliva, broth, and glucose 5%. Both saliva and broth significantly reduced the bactericidal activity of chlorhexidine against all microorganisms tested as compared to glucose 5% (p less than 0.01). Minimum bactericidal concentrations for indigenous flora were significantly lower than the values obtained for the "hospital-acquired" microorganisms (p less than 0.05). These observations of chlorhexidine inactivation by saliva may explain why chlorhexidine mouth rinsing is of limited value in decontaminating the oral cavity.

Analysis of Variance↗
PubMed1990

[Use of phase images in radionuclide ventriculography for topical diagnosis of Wolff-Parkinson-White syndrome and sources of pathologic rhythm of the heart ventricles].

The paper presents the results of the mapping of various types of the Wolff-Parkinson-White syndrome and ventricular arrhythmias by using phase images of radionuclide ventriculograms as compared to 12 leads and electrophysiological studies. Phase images are a highly informative method that supplements an electrophysiological study in the topical diagnosis of abnormal tracts and ventricular arrhythmias.

Adolescent↗
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↗