Biomedical subjects

G van Melle

Publications and source records attributed to G van Melle.

At least 55 records · Page 3Linked to original sources

PubMed1995

[Postoperative work incapacity, type of work resumed and residual pain following surgical treatment of lumbar herniated disk: prognostic factors].

The outcome in 258 patients 3 to 4 years after operation for lumbar disc herniation was studied. The median duration of postoperative work incapacity was 3.5 months; 202 (78%) patients resumed full time work in their previous job; 16 (6%) did not resume work due to lumbar pathology; 193 (75%) were free of pain. Predictive factors for a good professional outcome were a preoperative work incapacity inferior to 4 weeks and, for men only, operation at the L5-S1 level and the absence of daily lifting of heavy weights.

Adolescent↗

PubMed1995

Screening for excessive alcohol drinking. Comparative value of carbohydrate-deficient transferrin, gamma-glutamyltransferase, and mean corpuscular volume.

BACKGROUND: Screening medical patients for excessive alcohol drinking is important because minimal intervention by physicians is effective in reducing excessive consumption. Screening tests, such as biologic markers of alcohol consumption, should therefore be investigated to assess their validity to detect alcohol drinking. METHOD: Levels of carbohydrate-deficient transferrin (CDT), gamma-glutamyltransferase (GGT), and mean corpuscular volume (MCV) were determined in 1202 consecutive patients (20 to 75 years old) seen at the medical emergency ward (n = 552) and the primary care center (n = 650) of a city and teaching hospital. Each eligible patient was administered a CAGE questionnaire (an acronym for questions regarding cutting down on drinking, annoyance at others' concern about drinking, feeling guilty about drinking, and using alcohol as an eye-opener in the morning), and for each CAGE-positive patient (score > or = 2) as well as for a random sex-matched sample of CAGE-negative patients, standardized data about the recent level of alcohol drinking, morbidities, drug therapy, and smoking were recorded. The operating characteristics of CDT, GGT, and MCV were determined according to alcohol consumption and the CAGE test. Sensitivities, specificities, and receiver operating characteristic curves were computed to compare the tests at different cutoff values. RESULTS: Levels of CDT were elevated in 21% of men and 7% of women. According to recent alcohol consumption in men (> 60 g/d), the respective sensitivity and specificity of the tests were 0.58 and 0.82 for CDT, 0.69 and 0.65 for GGT, and 0.27 and 0.91 for MCV. Overall, receiver operating characteristic curves demonstrated similar performance of the three tests for screening of excessive alcohol drinking or alcohol abuse. However, in young men (< 40 years of age) and in smokers, CDT was superior to GGT or MCV. CONCLUSIONS: The study suggests that CDT determination may be a useful test for screening programs of excessive alcohol drinking in young male medical patients.

Adult↗

PubMed1995

Microglial responsiveness as a sensitive marker for trimethyltin (TMT) neurotoxicity.

Activation of microglia is a well-documented phenomenon associated with diverse pathological conditions of the central nervous system. In order to investigate the involvement of microglial cells in the neurotoxic action of the heavy metal compound trimethyltin, three-dimensional brain cell cultures were treated during an early developmental period, using concentrations at or below the limit of cytotoxicity. Microglial cells were studied by cytochemical staining, using horseradish peroxidase-conjugated B4 isolectin (GSI-B4). In parallel, neurotoxic effects were assessed by determining the content of synaptophysin and synapsin I, both in the total homogenates and in the synaptosomal fraction of the cultures. Changes in the content of the specific growth cone protein, GAP-43, were also analyzed. It was found that low, non-cytotoxic concentrations of TMT (10(-9) to 10(-8) M) caused a significant increase in the number and/or the clustering of microglial cells. A decrease in the synaptic protein (synapsin I, synaptophysin) content was detected at 10(-8) M of TMT in synaptosomal fractions, whereas in the total homogenates, changes in synaptic proteins and GAP-43 were observed only at the cytotoxic TMT concentration (10(-6) M). Although it remains to be shown whether the microglial response is caused by direct or indirect action of TMT, the present findings show that microglial responsiveness can be detected prior to any sign of neuronal degeneration, and may serve as a sensitive indicator for heavy metal neurotoxicity in the brain.

Animals↗

PubMed1995

Prediction of 18-month survival in patients with primary myelodysplastic syndrome. A regression model and scoring system based on the combination of chromosome findings and the Bournemouth score.

The predictive potential of six selected factors was assessed in 72 patients with primary myelodysplastic syndrome using univariate and multivariate logistic regression analysis of survival at 18 months. Factors were age (above median of 69 years), dysplastic features in the three myeloid bone marrow cell lineages, presence of chromosome defects, all metaphases abnormal, double or complex chromosome defects (C23), and a Bournemouth score of 2, 3, or 4 (B234). In the multivariate approach, B234 and C23 proved to be significantly associated with a reduction in the survival probability. The similarity of the regression coefficients associated with these two factors means that they have about the same weight. Consequently, the model was simplified by counting the number of factors (0, 1, or 2) present in each patient, thus generating a scoring system called the Lausanne-Bournemouth score (LB score). The LB score combines the well-recognized and easy-to-use Bournemouth score (B score) with the chromosome defect complexity, C23 constituting an additional indicator of patient outcome. The predicted risk of death within 18 months calculated from the model is as follows: 7.1% (confidence interval: 1.7-24.8) for patients with an LB score of 0, 60.1% (44.7-73.8) for an LB score of 1, and 96.8% (84.5-99.4) for an LB score of 2. The scoring system presented here has several interesting features. The LB score may improve the predictive value of the B score, as it is able to recognize two prognostic groups in the intermediate risk category of patients with B scores of 2 or 3. It has also the ability to identify two distinct prognostic subclasses among RAEB and possibly CMML patients. In addition to its above-described usefulness in the prognostic evaluation, the LB score may bring new insights into the understanding of evolution patterns in MDS. We used the combination of the B score and chromosome complexity to define four classes which may be considered four possible states of myelodysplasia and which describe two distinct evolutional pathways.

Chromosomes, Human↗

PubMed1995

[New retinal tumors in hereditary retinoblastoma].

364 eyes from 230 patients with retinoblastoma diagnosed and treated at the Lausanne University Eye Clinic from 1964 to June 1994 were retrospectively analyzed with respect to the risk of developing new tumour foci following initial therapy. Among them, 119 eyes from 90 hereditary affected patients were included, consisting of 86 bilateral cases and 4 unilateral cases. The mean follow-up was 65.5 months (5.5 years). A total of 46 new retinal tumours were detected in 21 patients. These new tumours had a size less than 1 disc diameter in 75% and were peripherally located in 78% of the cases, with a statistically significant preference for the horizontal meridians. No new tumours developed in the macular area. 50% appeared in children younger than 1 year and 80% before 2 years of age. 50% of the eyes with recurrences developed new tumours before 7.5 months following diagnosis, and 75% before 14 months. All patients showing recurrences did so before the age of 4.5.

Adolescent↗

PubMed1995

Evaluation of a new immunologic test kit for rapid detection of group A streptococci, the Abbott Testpack Strep A plus.

We compared the Testpack Strep A plus (TPSAP) enzyme-linked immunosorbent assay test for group A beta-hemolytic streptococcal (GAS) antigen rapid detection with blood agar culture in 454 pediatric patients with clinical pharyngitis. Of the 454 patients, 118 (25.9%) had positive oropharyngeal cultures for GAS. TPSAP sensitivity was 89.9% (106 of 118) and specificity was 95.8% (322 of 336). We conclude that the TPSAP is specific enough to indicate treatment for a patient with a positive test but that a negative test should be confirmed by culture.

Child↗

PubMed1995

Can early closure and restenosis after endoluminal stenting be predicted from clinical, procedural, and angiographic variables at the time of intervention?

OBJECTIVES: To develop a statistical model to assess the risk of early closure and restenosis on the basis of the information available at the time of stent implantation. DESIGN: An exploratory forward, stepwise multivariate logistic regression for each adverse event and multivariate polychotomous analysis for both events. SETTING: Tertiary referral centre for interventional treatment of coronary artery disease. PATIENTS: 243 consecutive, successful stenting procedures between 1986 and 1993 with the Wallstent, the Palmaz-Schatz and Wiktor stents with analysis of clinical, procedural, and angiographic variables. MEAN OUTCOME MEASURES: Early closure was defined as angiographically documented stent thrombosis within the first 3 weeks after implantation and restenosis according to the 50% reference diameter reduction criterion. RESULTS: Overall early closure and restenosis rates were 14.4% (35/243) and 19.2% (40/208, for a 97% repeat angiography rate). The statistical model predicted a worse outcome for male patients, with less restenosis in female patients. The only risk factor in female patients was the presence of collaterals to the target lesion. For male patients the following risk factors for closure and restenosis were retained: multiple stent implantation during the same session, the presence of collaterals to the target lesion, stenting of the left anterior descending artery or of the left circumflex artery, and bailout stenting. Only bailout stenting implied a decreased restenosis risk. CONCLUSIONS: Clinical, procedural and angiographic variables increase the risk for early closure and restenosis after endoluminal stenting. The prediction models described above need to be validated prospectively.

Angina Pectoris↗

PubMed1995

Hyperkinetic motor behaviors contralateral to hemiplegia in acute stroke.

Motor behaviors on the 'good side' of the body, i.e. ipsilateral to the hemispheric lesion, have not been studied systematically. We assessed motor behaviors in 20 consecutive patients during the acute phase (first 1-2 weeks) of a hemispheric stroke with hemiparesis. The behaviors were essentially rotations of the head, neck, eyes and trunk, orofaciopharyngeal or limb stereotypes, compulsive manipulation of the surroundings, or passive mobilization of the paralyzed arm or leg. These behaviors were found only with large infarcts in the territory of the internal carotid artery, middle cerebral artery and/or the anterior cerebral artery (ACA). All but two ACA infarcts involved the internal capsule and basal ganglia. The severity of the motor deficit and the presence of aphasia, neglect, or sensory loss were significantly correlated with the motor behaviors. Although the understanding of these behaviors remains unclear, we suggest that they may represent the clinical expression of early plastic changes of brain maps and circuits after an acute lesion; this is probably an active process induced by disinhibition, in order to establish new compensatory pathways.

Acute Disease↗

PubMed1994

Hematologic, clinical, and cytogenetic analysis in 109 patients with primary myelodysplastic syndrome. Prognostic significance of morphology and chromosome findings.

One hundred and nine patients with primary myelodysplastic syndrome (MDS) were classified according to the French-American-British (FAB) criteria: 27 refractory anemia (RA, 25%), 26 RA with ringed sideroblasts (RARS, 24%), 16 RA with excess of blasts (RAEB, 15%), 10 RAEB in transformation (RAEB-t, 9%), 25 chronic myelomonocytic leukemia (CMMoL, 23%), and five unclassifiable MDS (4%). Forty-three were women and 66 were men (sex ratio 2:3). Age ranged from 30-92 years (mean 69 years) with nine patients aged less than 50 years (8%). A cytogenetic result was obtained in all cases. At initial study, a chromosome defect was observed in 56% of patients. Rates of abnormality depended on FAB subtype: 52% in RA, 100% in RA 5q-, 50% in RARS, 56% in RAEB, 70% in RAEB-t and 44% in CMMoL. The most frequent single defects were del(5q), -7/del(7q), del(20q), Y loss, and +8. Except for the 5q- syndrome entity, specific chromosome defects were not associated with particular FAB subtypes. Bone marrow (BM) insufficiency (22%) and leukemic transformation (21%) were the most important causes of death. The rate of leukemic transformation increased with the number of dysplastic BM cell lineages and was also associated with karyotype complexity and the proportion of abnormal/normal metaphases. The longest median survivals were observed in RARS (142 months) and RA/RA5q- (91 months) types. Median survivals decreased with increasing Bournemouth score values. Patients with three abnormal cell lineages had a median survival shorter than those with one or two abnormal lineages. Similarly, patients with complex defects had shorter survival than those with single or double defects or a normal karyotype. There was no statistically significant difference between survival of NN (normal), AN (abnormal/normal), and AA patients or between survival of patients with del(5q), -7/del(7q), +8 or del(20q).

Adult↗

PubMed1994

[Superior oblique muscle paralysis and ocular torsion. What is the effect of measuring method on the results?].

BACKGROUND: The rotation of the eye-ball around Fick's Y-axis is called ocular torsion. A precise measurement of the torsional deviation can be clinically as critical in the diagnosis of some complex strabological disorders as in the assessment of some systemic diseases. MATERIALS AND METHODS: We measured the ocular torsion under binocular conditions by five measurement devices on 50 patients with superior oblique palsy. The comparison of the devices was performed using rank tests (Friedman, Wilcoxon signed rank). RESULTS: The 5 methods of measurement do not produce equivalent results. These findings confirm on a population of paretic patients similar published results obtained with healthy subjects. CONCLUSIONS: The simple Maddox rod and the synoptophore are among the most widely used methods to measure cyclotropia; this study reveals that these devices are the least reliable. Harm's tangent scale gives the most reliable results, in all directions of gaze; however, in inferior adduction, the synoptometer also yields a satisfactory measure of ocular torsion. In primary position, the double Maddox glass appears to be the most suitable instrument.

Adolescent↗

PubMed1992

Paternal selection favoring mutant alleles of the retinoblastoma susceptibility gene.

Penetrance and segregation rates of mutant Rb-1 alleles were assessed in all 51 members of eight kindreds with hereditary retinoblastoma by concomitant ophthalmologic examination and determination of seven intragenic restriction fragment length polymorphisms (RFLPs). Penetrance was in the range reported in the literature except for one family in which it was only 42.8%. However, the odds of transmitting a mutant Rb-1 allele from one generation to the next were 25:9 in this population, much above the Mendelian 1:1 ratio (P less than 0.025). This preferential transmission was discovered through the use of molecular information. Further analysis revealed that this distortion was due to preferential inheritance among children of male carriers (18:4, P less than 0.005). No difference from a 1:1 segregation ratio could be detected among the children of female carriers (7:5). These findings were consistent with a review of relevant data in the literature.

Alleles↗

PubMed1992

A four-proton-families model for pH-dependent enzyme activation: application to intestinal brush border sucrase.

Current concepts of pH-dependent enzyme function are expanded to consider enzymes with up to four key proton families. In an earlier paper the authors extended classical theory to explain the existence, in the acid ionization reaction, of two functionally distinct, V and K, proton families, exemplified by the 1988 sucrase three-proton-families model of Vasseur et al. They now propose that enzymes having two distinguishable proton families at each side of the pH-activity curves exist in nature although there is no previously published evidence of their existence. The resulting, more general, four-proton-families model is treated as a useful framework from which submodels can be derived by simplification, the simplest being the 1911 linear model of Michaelis and Davidsohn, which took into account two proton families out of the theoretical maximum of four proposed here. It is shown that whether a three-proton-families or a four-proton-families model can explain sucrase better is not merely a question of theory but also involves the practical question of having enough data, at each side of the pH spectrum, to permit making an unequivocal choice between the two alternatives. The paper concludes with a discussion of substrate-induced pK shifts according to both models.

Animals↗

PubMed1992

Aqueous humor analysis after Nd:YAG laser capsulotomy with the laser flare-cell meter.

Using the laser flare-cell meter (Kowa FC-1000), we conducted a prospective study analyzing the effect of Nd:YAG posterior capsulotomy on the quantity of aqueous particles, aqueous flare, and intraocular pressure in 65 eyes (58 patients). Aqueous particles increased at six hours, followed by flare rise which was significant at 18 hours after capsulotomy. Only 22 eyes (34%) had a significant flare rise over prelaser values. Anti-inflammatory therapy was necessary in only one patient. The mean intraocular pressure value did not rise significantly after capsulotomy. Acute intraocular hypertension (AIOHT) (> 7 mm Hg increase) occurred between three and six hours after laser therapy in 12 patients (19%), was related in time to particle rise, and always responded to a single dose of acetazolamide. Acute intraocular hypertension was strongly correlated with elevated aqueous particles (P < .0001) and somewhat correlated with flare rise (P < .036), but was not correlated with the intraocular lens position (bag or sulcus fixation). Our findings strongly suggest that trabecular meshwork clogging by debris generated by the capsulotomy is the mechanism at the origin of AIOHT.

Adult↗

PubMed1992

Pure motor stroke: a reappraisal.

We studied the correlations between the pattern of weakness, stroke type, topography, and etiology in 255 patients whose first stroke was manifested by isolated hemiparesis. They represented 14% of consecutively admitted stroke patients. The weakness distributions were as follows: face, upper limb, and lower limb (FUL) (50%); face and upper limb (FU) (29%); upper limb (U) (10%); and upper and lower limb (UL) (9%). Twenty-nine percent of the patients had dysarthria, which was of no localizing value. Less than one half of the patients had a deep infarct, and one third had a potential embolic source from the heart or large arteries. Logistic regression analysis showed that history of hypertension and type of weakness distribution were the main factors accounting for lesion localization: patients with FUL distribution and hypertension had a 90% probability of deep infarct; patients either with FUL distribution but no hypertension or with UL distribution and hypertension each had 70% probability of deep infarct. Pure motor monoparesis was almost never caused by a deep infarct. We suggest that the assumption of a lacunar etiology to a pure motor stroke should be applied only to patients with FUL involvement.

Brain↗

PubMed1991

[Chronic backache and occupational rehabilitation: prognostic factors].

The professional outcome in 65 patients with chronic low back pain who stayed in the Invalidity Insurance Medical Observation Center from 1982 to 1987 was studied retrospectively. The group studied was composed of 51 males and 14 females aged 28 to 61 years. Thirty-one out of 65 patients (48%) returned to work, 4 to full time employment (active group), whereas 34 did not return to work (inactive group). Data established during our initial observation served to compare the 2 groups by means of a logistic regression. No significant difference was found between the 2 groups of height, weight, age, family situation, severity of the X-ray findings and the existence of an associated psychiatric diagnosis were compared. On the other hand, the absence of professional training, female gender and the presence of a radicular syndrome significantly decreased the proportion of patients returning to work. If these 3 risk factors were absent, the chance of resuming work was 72%; if one was present it was 50%, and if there were 2 or 3 risk factors it was 28%.

Adult↗

PubMed1991

[Ozone, ventilatory function and bronchial reactivity].

Forty adult hospital workers were followed prospectively in 1989 by monthly assessment of the lung function and bronchial responsiveness to methacholine in a rural region in Switzerland. No correlation was demonstrated between these values and the concentrations of tropospheric ozone. Nevertheless, this is not incompatible with previous studies showing impairment of ventilatory function in subjects exposed to ozone, for several reasons: ozone levels in 1989 were low, the indoor concentrations were lower than outdoors and the volunteers performed little or no physical activity.

Adult↗

PubMed1991

Prognostic factors in papillary carcinoma of the thyroid.

In a retrospective study of 119 patients, followed for 1 to 30 years after treatment of a papillary carcinoma of the thyroid, the authors searched for possible prognostic factors of the risk of recurrence. Microcarcinomas, anaplastic tumors and Hürthle cell carcinomas were excluded from the study. In a univariate analysis, age (greater than 45 years), sex (male), loss of histologic differentiation, size (greater than 3 cm), presence of carcinomatous lymphangitis, extrathyroid extension, and presence of metastasis at diagnosis were associated with a higher recurrence rate; type of growth and multifocality were not significant. In a multivariate analysis (logistic regression), age, size, and carcinomatous lymphangitis were significant predictors for women, whereas metastasis at diagnosis and cystic growth were significant for men.

Adult↗

PubMed1991

Absence of metabolic effects of the topical carbonic anhydrase inhibitors MK-927 and sezolamide during two-week ocular administration to normal subjects.

Potential systemic effects of the racemic carbonic anhydrase inhibitor MK-927 and its S-enantiomer, sezolamide hydrochloride, after topical ocular administration were investigated in a double-masked, randomized, placebo-controlled study in 16 healthy volunteers. A controlled diet was started 4 days before initiation of treatment and continued throughout the study. For 14 days six volunteers received bilaterally one drop of 2% MK-927 (1.2 mg) q.i.d., six received one drop of 1.8% sezolamide (1.1 mg) q.i.d., and four received the common vehicle q.i.d. Blood and urine electrolytes and acid-base profiles were measured before and on days 1, 7, and 14 of treatment, and 24-hour urine samples were collected daily. All values were compared with those on the pretreatment day. Taking the circadian variations of the parameters into account, no significant treatment effect was observed in either the daily profiles or the 14-day cumulative sodium, potassium, and citrate excretions. Because the usual variability of the measured biologic parameters has been reduced markedly by the stringent requirements of this study, it can be concluded that the induction of clinically significant metabolic changes by topically administered MK-927 or sezolamide is unlikely.

Administration, Topical↗