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Biomedical subjects

C Ruffieux

Publications and source records attributed to C Ruffieux.

At least 19 recordsLinked to original sources
PubMed2006

Continuous assessment of electrical epileptic activity in acute stroke.

OBJECTIVE: To determine the incidence and risk factors of electrical seizures and other electrical epileptic activity using continuous EEG (cEEG) in patients with acute stroke. METHODS: One hundred consecutive patients with acute stroke admitted to our stroke unit underwent cEEG using 10 electrodes. In addition to electrical seizures, repetitive focal sharp waves (RSHWs), repetitive focal spikes (RSPs), and periodic lateralized epileptic discharges (PLEDs) were recorded. RESULTS: In the 100 patients, cEEG was recorded for a mean duration of 17 hours 34 minutes (range 1 hour 12 minutes to 37 hours 10 minutes). Epileptic activity occurred in 17 patients and consisted of RSHWs in seven, RSPs in seven, and PLEDs in three. Electrical seizures occurred in two patients. On univariate Cox regression analysis, predictors for electrical epileptic activity were stroke severity (high score on the National Institutes of Health Stroke Scale) (hazard ratio [HR] 1.12; p = 0.002), cortical involvement (HR 5.71; p = 0.021), and thrombolysis (HR 3.27; p = 0.040). Age, sex, stroke type, use of EEG-modifying medication, and cardiovascular risk factors were not predictors of electrical epileptic activity. On multivariate analysis, stroke severity was the only independent predictor (HR 1.09; p = 0.016). CONCLUSION: In patients with acute stroke, electrical epileptic activity occurs more frequently than previously suspected.

Adult↗
PubMed2003

Comparison of three bone ultrasounds for the discrimination of subjects with and without osteoporotic fractures among 7562 elderly women.

UNLABELLED: Bone ultrasound measures (QUSs) can assess fracture risk in the elderly. We compared three QUSs and their association with nonvertebral fracture history in 7562 Swiss women 70-80 years of age. The association between nonvertebral fracture was higher for heel than phalangeal QUS. INTRODUCTION: Because of the high morbidity and mortality associated with osteoporotic fractures, it is essential to detect subjects at risk for such fractures with screening methods. Because quantitative bone ultrasound (QUS) discriminated subjects with osteoporotic fractures from controls in several cross-sectional studies and predicted fractures in prospective studies, QUS could be more practical than DXA for screening. MATERIAL AND METHODS: This cross-sectional and retrospective multicenter (10 centers) study was performed to compare three QUSs (two heel ultrasounds: Achilles+ [GE-Lunar] and Sahara [Hologic]; the phalanges: ultrasound DBM sonic 1200 [IGEA]) for determining by logistic regression nonvertebral fracture odds ratio (OR) in a sample of 7562 Swiss women, 75.3 +/- 3.1 years of age. The two heel QUSs measured the broadband ultrasound attenuation (BUA) and the speed of sound (SOS). In addition, Achilles+ calculated the stiffness index (SI) and the Sahara calculated the quantitative ultrasound index (QUI) from BUA and SOS. The DBM sonic 1200 measured the amplitude-dependent SOS (AD-SOS). RESULTS: Eighty-six women had a history of a traumatic hip fracture after the age of 50, 1594 had a history of forearm fracture, and 2016 had other nonvertebral fractures. No fracture history was reported by 3866 women. Discrimination for hip fracture was higher than for the other nonvertebral fractures. The two heel QUSs had a significantly higher discrimination power than the QUSs of the phalanges, with standardized ORs, adjusted for age and body mass index, ranging from 2.1 to 2.7 (95% CI = 1.6, 3.5) compared with 1.4 (95% CI = 1.1, 1.7) for the AD-SOS of DBM sonic 1200. CONCLUSION: This study showed a high association between heel QUS and hip fracture history in elderly Swiss women. This could justify integration of QUS among screening strategies for identifying elderly women at risk for osteoporotic fractures.

Age Factors↗
PubMed2001

Irritancy of the skin disinfectant n-propanol.

Hand disinfection with short-chain aliphatic alcohols, so-called "rub-ins" is the method of choice for cross-infection prevention in health care environments, but their irritant potential is not well known. Skin tolerance is a major compliance factor, and a high proportion of health care workers suffer from low-grade irritant contact dermatitis. Therefore, assessment of the irritancy of the skin disinfectant n-propanol 60%, and comparative 100% and 0% solutions, was performed in the setting of experimental low-grade ICD. ICD was induced by overnight patch exposure to H2O, and to 0.3% sodium dodecyl sulfate (SDS), in 12 probands, followed by repeated open exposure to the test substances. Outcome variables were transepidermal water loss (TEWL), and skin surface capacitance. On skin sites pre-irritated by SDS, all n-propanol concentrations (100%, 60%, 0%) increased TEWL. However, a clear divergence appeared between pure n-propanol, and the lower concentrations. In contrast to pure n-propanol, n-propanol 60% and 0% had no significant effect on TEWL on H2O-pre-irritated skin sites. Capacitance of pre-irritated skin sites was increased by exposure to H2O-containing n-propanol solutions (60% and 0%). These results show a clear difference between the irritant potential of n-propanol 100% on one side, and n-propanol 60% and 0% on the other side. The level of pre-existent skin irritation is a pertinent factor in susceptibility to irritation, as the irritant potential of n-propanol 60%, the concentration used in daily practice, and n-propanol 0% (water) became significant only on detergent-irritated skin. Thus, preventive skin care may be a constructive approach in increasing tolerance of modern hand disinfection practices.

1-Propanol↗
PubMed1998

Fitting the distributions of length of stay by parametric models.

OBJECTIVES: The purpose of this study was to assess the adequacy of three widely used models--Lognormal, Weibull, and Gamma--for describing the distribution of length of stay. This is a fundamental step in the development of outliers resistant (robust) methods for the statistical analysis of this kind of data, where the main objective is to determine measures of average and total resource consumption of groups of patients. Current practice uses several types of trimming rules, many of which are based on the Lognormal model, although theoretical and experimental bases are still insufficient. METHODS: The three models were adjusted using robust procedures based on M-estimators to approximately 5 million stays grouped by Diagnosis-Related Groups (DRGs). The resulting 3,279 samples were collected in five European countries during 3 years. RESULTS: Most of the distributions observed could be fitted with one of these models. The descriptions provided by the Gamma and the Weibull models were similar, and the Gamma model could be omitted. The casemix description provided by the Log-normal-Weibull family was, for certain countries, significantly better than the one provided by the single Lognormal model. Often, for a given DRG and a given country, length of stay distributions could be described with the same model during several years. A given DRG, however, usually had to be described by means of different models for different countries. CONCLUSIONS: Practical and conceptual consequences of the results are discussed. They can be extended to the analyses of other consumption variables used in health services. Statistical procedures for casemix description, including current rules of trimming, should be improved by means of more flexible families of models.

Belgium↗
PubMed1995

Rosemary components inhibit benzo[a]pyrene-induced genotoxicity in human bronchial cells.

The commonly used spice and flavouring agent, rosemary, derived from the leaves of the plant Rosmarinus officinalis L., displays antioxidant properties in foods and in biological systems. Moreover, in animal models rosemary components were found to inhibit the initiation and tumour promotion phases of carcinogenesis. In this work, we studied the mechanisms by which rosemary components block initiation of carcinogenesis by the procarcinogen benzo[a]pyrene (B[a]P) in human bronchial epithelial cells (BEAS-2B). Whole rosemary extract (6 micrograms/ml) or an equivalent concentration of its most potent antioxidant constituents, carnosol or carnosic acid, inhibited DNA adduct formation by 80% after 6 h co-incubation with 1.5 muM B[a]P. Under similar conditions, cytochrome P450 (CYP) 1A1 mRNA expression was 50% lower in the presence of rosemary components, and CYP1A1 activity was inhibited 70-90%. The observed reduction of DNA adduct formation by rosemary components may mostly result from the inhibition of the activation of benzo[a]pyrene to its ultimate metabolites. Carnosol also affected expression of the phase II enzyme glutathione-S-transferase which is known to detoxify the proximate carcinogenic metabolite of B[a]P. Treatment of BEAS-2B cells with carnosol (1 microgram/ml) for 24 h resulted in a 3- to 4-fold induction of GST pi mRNA. Moreover, expression of a second important phase II enzyme, NAD(P)H: quinone reductase, was induced by carnosol in parallel with GST pi. Therefore, rosemary components have the potential to decrease activation and increase detoxification of an important human carcinogen, identifying them as promising candidates for chemopreventive programs.

Anticarcinogenic Agents↗
PubMed1993

Exploring models for the length of stay distribution.

Diagnosis Related Groups (DRG) are frequently used to standardize the comparison of consumption variables, such as length of stay (LOS). In order to be reliable, this comparison must control for the presence of outliers, i.e. values far removed from the pattern set by the majority of the data. Indeed, outliers can distort the usual statistical summaries, such as means and variances. A common practice is to trim LOS values according to various empirical rules, but there is little theoretical support for choosing between alternative procedures. This pilot study explores the possibility of describing LOS distributions with parametric models which provide the necessary framework for the use of robust methods.

Adolescent↗
PubMed1992

Serum T-kininogen levels increase two to four months before death.

We have reported an accumulation of T-kininogen mRNA in the liver of aging Sprague-Dawley rats. T-kininogen is a cysteine proteinase inhibitor. Since a disruption of the intracellular protein degradation machinery is known to occur during senescence, we wished to further define the role of this protein in the aging process. As a first step, we have measured T-kininogen levels both in serum and within the liver. We have found that serum protein levels are indeed augmented during senescence, although not as dramatically as the mRNA (2.5-fold versus 8.3-fold). Immunocytochemistry, as well as Western blot analysis suggests that this is due to the presence of T-kininogen within hepatic cells in aged rats. Life-long dietary restriction, a known age-prolonging treatment, decreases the overexpression of the protein in 24-month-old rats. Later, diet-restricted animals still show an increased expression from the gene, the effect being delayed but not abolished by dietary manipulation. Interestingly, a longitudinal study indicated the existence of a positive correlation between the time of increase of serum T-kininogen and the time of death of the animal. Serum T-kininogen was found to increase 2.5-4 months before death.

Aging↗
PubMed1992

The circadian rhythm of the perinatal mortality rate in Switzerland.

The authors examine the relation between the perinatal mortality rate (PMR), birth weight in four categories, and hour of birth throughout the week in Switzerland, using data on 672,013 births and 5,764 perinatal deaths recorded between 1979 and 1987. From Monday to Friday, the PMR follows a circadian rhythm with a regular increase from early morning to evening, with a peak for babies born between 7 and 8 p.m. This pattern of variation has two main components: The circadian rhythms for the proportion of births in the four weight categories and the PMR circadian rhythm for babies weighing more than 2.5 kg. According to a cosinor model, which describes about 40% of the total variation in the PMR, the most important determinants are changes in the proportions of births: Low birth weight increases toward the afternoon and night. Mechanisms underlying the weight-specific timing of birth are discussed, including time selection of birth according to obstetric risks, the direct effect of neonatal and obstetric care, and chronobiologic behavior.

Birth Weight↗
PubMed1990

Tufted angioma.

The clinical and histological description of 2 cases of tufted angioma is presented.

Diagnosis, Differential↗
PubMed1990

[Treatment of condylomata acuminata: efficacy of the carbon dioxide laser].

The treatment of condyloma acuminatum may be long and tiresome owing to frequent recurrences, and the multiple physical or chemical therapies utilized bear witness to the difficulties often encountered in trying to eradicate the lesions. CO2 laser is a therapeutic alternative with some advantages, such as minimal peripheral thermal necrosis with a lower risk of scar or stricture, haemostasis and perhaps sterilizing effect. Between 1985 and 1987, 69 patients (58 men and 11 women; mean age 29 years) treated with CO2 laser and followed up for at least 6 months without recurrence entered our study. All patients had multiple lesions located in the genital region in 32 cases, in the anal region in 22 cases and in both the genital and anal regions in 15 cases. The majority of patients (85%) had been referred to us owing to failure of previous treatments. We used the CO2 laser coupled with a hand-piece, working by continuous emission, with a power of 300 to 800 watts/sq.cm. Superficial vaporization of the area around the condyloma was systematically performed. Seventy-seven percent of the patients were treated under local anaesthesia. In 16 patients with intra-anal or profuse ano-genital lesions the first vaporization was carried out under general anaesthesia. Twenty-two patients (32%) were cured in one session and 19 (28%) in two sessions. Twenty-eight patients had several recurrences requiring repeated treatments (3 to 5 in 17 cases, 6 to 10 in 10 cases, 31 in 1 case) over a 2 to 17 months' period. No major complications, notably scarring, were observed.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1989

[Herpes gestationis: a case].

Herpes gestationis is a rare autoimmune disorder of pregnancy. Diagnosis may be suspected by the nature and localisation of the eruption and its recurrence. Only histologic examination of a skin biopsy with immunofluorescence revealing a linear deposit of C3 along the basement membrane confirms the diagnosis. Corticotherapy is the treatment of choice, local or general, depending on the severity of the symptoms. We report the observation of two pregnancies occurring in the same patient. The clinical and paraclinical manifestations of the first pregnancy did not recur in the second pregnancy. This constitutes an unusual case among the observations reported in the literature. Furthermore, we touch upon the immunological mechanisms of herpes gestationis.

Adult↗
PubMed1988

Robust regression in biological assay: application to the evaluation of alternative experimental techniques.

Robust Huber type regression and testing of linear hypotheses are adapted to statistical analysis of parallel line and slope ratio assays. They are applied in the evaluation of results of several experiments carried out in order to compare and validate alternatives to animal experimentation based on embryo and cell cultures. Computational procedures necessary for the application of robust methods of analysis used the conversational statistical package ROBSYS. Special commands for the analysis of parallel line and slope ratio assays have been added to ROBSYS.

Animal Testing Alternatives↗