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Biomedical subjects

L Genton

Publications and source records attributed to L Genton.

At least 19 recordsLinked to original sources
PubMed2005

Physiological functions should be considered as true end points of nutritional intervention studies.

With the beginning of this millennium it has become fashionable to only follow 'evidence-based' practices. This generally-accepted approach cruelly negates experience or intelligent interpretation of pathophysiology. Another problem is that the great 'meta-analysts' of the present era only accept end points that they consider 'hard'. In the metabolic and nutritional field these end points are infection-related morbidity and mortality, and all other end points are considered 'surrogate'. The aim of this presentation is to prove that this claim greatly negates the contribution of more-fundamentally-oriented research, the fact that mortality has multifactorial causes, and that infection is a crude measure of immune function. The following problems should be considered: many populations undergoing intervention have low mortality, requiring studies with thousands of patients to demonstrate effects of intervention on mortality; nutrition is only in rare cases primary treatment, and in many populations is a prerequisite for survival rather than a therapeutic modality; once the effect of nutritional support is achieved, the extra benefit of modulation of the nutritional support regimen can only be modest; cost-benefit is not a valid end point, because the better it is done the more it will cost; morbidity and mortality are crude end points for the effect of nutritional intervention, and are influenced by many factors. In fact, it is a yes or no factor. In the literature the most important contributions include new insights into the pathogenesis of disease, the diminution of disease-related adverse events and/or functional improvement after therapy. In nutrition research the negligence of these end points has precluded the development and validation of functional end points, such as muscle, immune and cognitive functions. Disability, quality of life, morbidity and mortality are directly related to these functional variables. It is, therefore, of paramount importance to validate functional end points and to consider them as primary rather than surrogate end points.

Biomarkers↗
PubMed2004

Five-year follow-up after pediatric living related small bowel transplantation between two monozygotic twins.

Two 13-year-old monozygotic twins were used for living related small bowel transplantation (SBTx). The recipient presented with short gut syndrome secondary to complicated abdominal surgery. The indication for SBTx was based on a failure to thrive and a poor tolerance of TPN. The donor was an identical twin, as demonstrated by skin graft acceptance, which allowed performance of SBTx without immunosuppression. Growth charts were used to follow intestinal absorption functions and body composition. The donor was used as a control for the recipient. The recipient, who was transplanted with 160 cm of donor ileum, was discharged on postoperative day 62 on a regular diet. Before SBTx the recipient was 10 kg lighter in body weight than the donor, a gap that was progressively reduced over the follow-up period. A height deficit of 3 cm reversed within 1 year after SBTx. A 10-kg deficit in fat-free body mass was completely extinguished within 18 months. By 18 months posttransplant, recipient serum albumin and prealbumin were normal and comparable to donor values. d-Xylose absorption in the recipient remained lower than that in the donor. Within 6 months fecal fat excretion normalized in the recipient. d-Xylose absorption and fecal fat excretion were always within a normal range in the donor.

Adolescent↗
PubMed2004

Negative neurofunctional effects of frequency, depth and environment in recreational scuba diving: the Geneva "memory dive" study.

OBJECTIVES: To explore relationships between scuba diving activity, brain, and behaviour, and more specifically between global cerebral blood flow (CBF) or cognitive performance and total, annual, or last 6 months' frequencies, for standard dives or dives performed below 40 m, in cold water or warm sea geographical environments. METHODS: A prospective cohort study was used to examine divers from diving clubs around Lac Léman and Geneva University Hospital. The subjects were 215 healthy recreational divers (diving with self-contained underwater breathing apparatus). Main outcome measures were: measurement of global CBF by (133)Xe SPECT (single photon emission computed tomography); psychometric and neuropsychological tests to assess perceptual-motor abilities, spatial discrimination, attentional resources, executive functioning, and memory; evaluation of scuba diving activity by questionnaire focusing on number and maximum depth of dives and geographical site of the diving activity (cold water v warm water); and body composition analyses (BMI). RESULTS: (1) A negative influence of depth of dives on CBF and its combined effect with BMI and age was found. (2) A specific diving environment (more than 80% of dives in lakes) had a negative effect on CBF. (3) Depth and number of dives had a negative influence on cognitive performance (speed, flexibility and inhibition processing in attentional tasks). (4) A negative effect of a specific diving environment on cognitive performance (flexibility and inhibition components) was found. CONCLUSIONS: Scuba diving may have long-term negative neurofunctional effects when performed in extreme conditions, namely cold water, with more than 100 dives per year, and maximal depth below 40 m.

Adult↗
PubMed2003

Food intake in 1707 hospitalised patients: a prospective comprehensive hospital survey.

BACKGROUND & AIMS: This study aimed to assess the ability of the hospital meal service to meet patients' nutritional needs. METHODS: All hospitalised patients who received 3 meals/day without artificial nutritional support were included. The nutritional values of food served, consumed and wasted during a 24 h period were compared to patients' needs estimated as energy: 110% Harris-Benedict formula; protein: 1.2 or 1.0 g/kg bodyweight/day for patients < or = or > 65 years old, respectively. A structured interview recorded patients' evaluation of the meal quality, their reasons for non-consumption of food and the relationship between food intake and disease. RESULTS: Out of 1707 patients included, 1416 were fully assessable (59% women; 68+/-21 years; body mass index: 24.3+/-5.1 kg/m(2)). Daily meals provided 2007+/-479 kcal and 78+/-21 g of protein and exceeded patients' needs by 41% and 15%, respectively. However, 975 patients did not eat enough. Plate waste was 471+/-372 kcal and 21+/-17 g of protein/day/patient. Moreover, the food intake of 572 (59%) of these underfed patients was not predominantly affected by disease. Logistic regression analyses identified as other risk factors: elevated BMI, male gender, modified diet prescription, length of stay <8 or > or = 90 days and inadequate supper. CONCLUSION: Despite sufficient food provision, most of the hospitalised patients did not cover their estimated needs. Since insufficient food intake was often attributed to causes other than disease, there should be potential to improve the hospital meal service.

Aged↗
PubMed2003

Four year nutritional follow up after living related small bowel transplantation between monozygotic twins.

While small bowel transplantation (SBTX) may allow parenteral nutrition independence in the case of short bowel syndrome, its effects on body composition and growth are unclear. For the first time, a paediatric living related SBTX was performed between monozygotic twins. This case report describes their four year nutritional follow up. The 13 year old recipient and his healthy brother underwent measurements of body composition by 50 kHz bioimpedance analysis and bone mineral density of the femoral neck and total femur by dual energy x ray absorptiometry. Xylose tests and measurements of faecal fat evaluated gut absorption. All tests were performed before and after SBTX. Body weight increased from 34.7 to 51.9 kg in the recipient and from 45.0 to 53.2 kg in the donor within four years. The recipient caught up with the height and fat free mass of his brother within two years. Fat mass, and total femur and femoral neck densities are still lower in the recipient than in the donor four years after SBTX (-1.2 kg, -0.087 g/cm(2), -0.035 g/cm(2)). The xylose test of the recipient was still abnormally low after four years (1.37 mmol/l) and faecal fat was high until two years after SBTX (March 2001: 12 g/24 h). The donor always showed normal xylose tests and faecal fat, except for one episode of high faecal fatty acids about 10 months after SBTX. SBTX improved the nutritional state and growth of the graft recipient although body composition, femoral bone mineral densities, and intestinal absorption had not completely normalised after four years.

Adolescent↗
PubMed2002

Is time since hip fracture influencing the discrimination between fractured and nonfractured subjects as assessed at the calcaneum by three technologically different quantitative ultrasound devices?

Because quantitative ultrasound (QUS) instruments from different manufacturers have significant technical differences, it is difficult to assess whether all of them can discriminate similarly between osteoporotic fractures and age-matched controls. Thus, to avoid any bias, reliable comparative assessment of the QUS devices should be carried out on the same population. Few studies have fulfilled this condition. Another source of variability in cross-sectional studies in which fractured and nonfractured subjects are compared is the time since osteoporotic fracture. Our study evaluated the ability of three calcaneal QUS devices to discriminate patients with osteoporotic hip fracture from control subjects, using the same population. In addition, a subset of patients was re-measured about 9 months after the hip replacement surgery to check how the time since fracture affects the discriminatory ability of the different QUS devices. Fifty postmenopausal hip-fractured patients and 46 postmenopausal age-matched controls were included in this study and measured on three QUS devices, as well as 50 young healthy controls to calculate the T-score. Odds ratio results showed that a decrease in UBIS trade mark BUA of 1 SD was associated with a significant increase in fracture risk (odds ratio adjusted = 2.30) comparable with Sahara broadband ultrasound attenuation (BUA) (OR adj. = 2.30), and Achilles BUA (OR adj. = 3.5). However, given the large overlap between the 95% intervals of each OR and for the areas under ROC curves, no significant difference was found between them. In the subset of 15 hip-fractured subjects, no significant differences were found between ultrasound parameters of the first visit and 9 months after except for the heel width (soft tissue variation). Odds ratio and areas under the curve (AUC) tend to increase from visit 1 to 2 for the BUA and decrease substantially for the SOS for all but the Lunar Achilles+. Nonsignificant correlation was found between the absolute difference of the ultrasound parameters measured at the two visits and the time since fracture, except for the Sahara SOS (r = 0.45; P < 0.04). In conclusion, no significant differences between QUS technologies were observed in their positive and significant ability to discriminate hip-fractured patient from controls. However, this statement is shadowed when taking into account the time since fracture which seems to negatively influence results obtained on dry versus wet QUS systems. As a result, it is advisable that such parameters would be taken into account when designing a study aimed to demonstrate the discriminatory ability of heel ultrasound between normal and hip-fractured patients.

Adult↗
PubMed2002

Monitored impact loading of the hip: initial testing of a home-use device.

Many studies have been done involving exercise, impact loading, and the effect on BMD. In some of these studies, particularly those involving outpatient activity, compliance and the specific parameters of an individual's impact loading have been difficult to monitor effectively. In this study, an individual, home-use platform was used to record daily, specific, and reproducible impact forces generated during a heel drop exercise. At three centers over 24 months, we conducted a randomized, prospective study of 157 osteoporotic and osteopenic women, aged 60-85 years. A total of 99 patients used the home Osteocare device (OrthoGenesis Incorporated, Northborough, Massachusetts USA) to generate a reproducible and specific daily impact program (active group). Controls (32) performed a similar motion on the unit but without trying to trigger an impact force (sham group), and 26 patients did no prescribed heel drop exercise (control group). All groups had the same calcium and vitamin D supplementation. Hip DXA was performed at baseline and every 6 months during the entire study duration. Compliance with the 3-5 min routine was high, and patients were able to consistently achieve the specific targeted impact range. Pooled BMD results showed no significant differences between groups in overall BMD measurements. However, a classification model that looked at individual site-specific BMD changes showed that more than 75% of the active group responded (versus 62% for both the sham and the control groups) by maintaining or increasing site-specific hip BMD over the 2-year trial. In fact, at the end of the study, 45% of the actives were gainers versus 12% and 22% in the sham and control groups, respectively. This study suggests that hip BMD may be maintained through a brief, safe, at-home, monitored impact loading program.

Absorptiometry, Photon↗
PubMed2002

Longitudinal quality control methodology for the quantitative ultrasound Achilles+ in clinical trial settings.

Appropriate quality assurance (QA) and quality control (QC) procedures have been well developed and validated for dual X-ray absorptiometry (DXA), and are widely applied in multicenter clinical trials to monitor device stability used to check the treatment effects on bone mineral density. This is not yet the case for quantitative ultrasound (QUS) technology, for which no QC approaches have yet been fully tested. The first Achilles (GE-Lunar Corporation, Madison, WI, USA) has been on the market for 10 years (1991). The goal of this study was to develop the QC methodology for the QUS Achilles+ device using its past/current experience (log and maintenance files.) as well as by integrating the progress made over the last years in the ultrasound domain so as to better understand the influence of temperature on ultrasound parameters. Because of the lack of confidence in the external black rubber phantom used in daily QC with the Achilles+, to monitor the device stability, we selected several QC parameters known to be influenced by potential malfunctions as experienced by the maintenance department of GE-Lunar company as well as the physical approach. These are phantom temperature-adjusted speed of sound (PSOS-TC) and broadband ultrasound attenuation (PBUA-TC), water speed of sound error (WSE), water spectrum slope (WSS) and water gain (WG). We used four Achilles+ devices perfectly stable during their entire QC range, to calculate the optimum thresholds (based mostly on 95% confidence interval) for each of these parameters as well as the precision for the in vitro SOS and BUA. An additional not fully stable Achilles device has been used to run a QC procedure example. The precision expressed as the CV was 0.22% and 0.65% for the PSOS-TC and PBUA-TC, respectively. The alarm thresholds used for QC process are +/- 0.6%, +/- 1.9%, +/- 6.8 m/s, +/- 5.3% and +/- 7.3% for the PSOS-TC, PBUA-TC, WSE, WSS and WG, respectively. Applying a logical approach on the impact of each parameter on each other as well as their respective reactivity to malfunctions, we build a QC process flowchart meant to detect real malfunction in the daily QC. We found that in case of real malfunctions, the in vivo SOS should be decreased by 1.33 m/s for each 1 m/s increase in WSE. Unfortunately, in vivo BUA can not be adjusted when real malfunction occurs. Nevertheless, the BUA can be qualified as bad quality data and excluded from the medical interpretation. Using the currently available phantom and parameters, the best possible QC procedures to detect long-term drift in the daily QC of the Achilles+ was developed. To fully validate our approach and gain confidence in the defined limits it is our plan to apply this QC processing to a higher number of QUS devices.

Bone and Bones↗
PubMed2001

Single prediction equation for bioelectrical impedance analysis in adults aged 20--94 years.

Existing equations for bioelectrical impedance analysis (BIA) are of limited use when subjects age or become overweight because these equations were developed in young, normal-weight subjects and are not valid in elderly or overweight people. The purpose of this study was to validate a single BIA equation in healthy white subjects aged 22--94 y with a body mass index between 17.0 and 33.8 kg/m(2). Healthy subjects (202 men and 141 women) aged 20--94 y were measured by two methods: fat-free mass (FFM) was measured by dual-energy x-ray absorptiometry (Hologic QDR-4500) and by a bioelectrical impedance analyzer (Xitron 4000B). Validity of BIA was assessed by double cross validation. Because correlations were high (r = 0.986--0.987) and prediction errors low, a single equation was developed using all subjects, as follows: FFM = -4.104 + (0.518 x height(2)/resistance) + (0.231 x weight) + (0.130 x reactance) + (4.229 x sex: men = 1, women = 0). FFM predicted with dual-energy x-ray absorptiometry was 54.0 +/- 10.7 kg. BIA-predicted FFM was 54.0 +/- 10.5 kg (r = 0.986, standard error of the estimate = 1.72 kg, technical error = 1.74 kg). In conclusion, the new Geneva BIA equation was valid for prediction of FFM in healthy adults aged 22--94 y with body mass indexes between 17.0 and 33.8 kg/m(2). Inclusion of reactance in the single prediction equation appeared to be essential for use of BIA equations in populations with large variations in age or body mass.

Absorptiometry, Photon↗
PubMed2001

Age-related differences in fat-free mass, skeletal muscle, body cell mass and fat mass between 18 and 94 years.

OBJECTIVE: To determine (1) lean and fat body compartments, reflected by fat-free mass (FFM), appendicular skeletal muscle mass (ASMM), body cell mass (BCM), total body potassium (TBK), fat mass and percentage fat mass, and their differences between age groups in healthy, physically active subjects from 18 to 94 y of age; and (2) if the rate of decrease in any one of the parameters by age might be accelerated compared to others. METHODS: A total of 433 healthy ambulatory Caucasians (253 men and 180 women) aged 18--94 y were measured by dual-energy X-ray absorptiometry (DXA) and whole body scintillation counter (TBK counter) using a large sodium iodide crystal (203 mm diameter). RESULTS: The ASMM change (-16.4 and -12.3% in men and women, respectively) in >75 y-old compared to 18 to 34-y-old subjects was greater than the FFM change (-11.8 and -9.7% in men and women, respectively) and this suggests that skeletal muscle mass decrease in older subjects was proportionally greater than non-skeletal muscle mass. BCM (-25.1 and -23.2% in men and women, respectively) and TBK differences were greater than the differences in FFM or ASMM suggesting altered composition of FFM in older subjects. Women had lower peak FFM, ASMM, BCM and TBK than men. CONCLUSIONS: The decline in FFM, ASMM, BCM and TBK is accelerated in men and women after 60 y of age and FFM, ASMM, BCM and TBK are significantly lower than in younger subjects. Fat mass continued to increase until around 75 y.

Absorptiometry, Photon↗
PubMed2001

Total body mass, fat mass, fat-free mass, and skeletal muscle in older people: cross-sectional differences in 60-year-old persons.

OBJECTIVES: To evaluate body composition parameters, including fat-free mass (FFM), appendicular skeletal muscle mass (ASMM), relative skeletal muscle mass (RSM) index, body cell mass (BCM), BCM index, total body potassium (TBK), fat mass, percentage fat mass (FM), and their differences between age groups and to evaluate the frequency of sarcopenia in healthy older subjects DESIGN: Cross-sectional, nonrandomized study. SETTING: Outpatient clinic. PARTICIPANTS: Ninety-one healthy men and 100 healthy women age 60 and older. MEASUREMENTS: FFM, ASMM, FM, and percentage fat mass by whole-body dual-energy x-ray absorptiometry; TBK, BCM, and TBK/FFM ratio by whole body potassium-40 counter. RESULTS: All lean body mass parameters were significantly (P <.05) lower in subjects age 80 and older than in those age 70 to 79, except ASMM in women. Mean FFM was 4.2 kg (7.3%) lower in men age 80 and older than in those younger than 70 and 2.9 kg (6.8%) lower in women age 80 and older than in those younger than 70. The skeletal muscle mass, reflected by ASMM, decreased more than FFM. This suggests that nonskeletal muscle mass is proportionally preserved during aging. Forty-five percent of men and 30% of women were sarcopenic by definition of BCM index and 11.0% of men and women by definition of RSM index. CONCLUSIONS: Significant age-related differences exist in body composition of older men and women between age 60 and 95. The greater decrease in TBK and BCM than the decrease in FFM and skeletal muscle mass suggests changing composition of FFM with age. Lack of agreement between two independent sarcopenia indexes suggests that further refinement in the definition of a sarcopenia index is necessary.

Absorptiometry, Photon↗
PubMed2001

Feeding the intensive care patient.

The present review highlights recent findings (focusing on papers published between October 1999 and December 2000) in nutritional support of intensive care unit patients. During the past year, research focused on the use of enteral nutrition versus parenteral nutrition, and on the best composition of enteral nutrition and parenteral nutrition according to the clinical condition of the patient. With regard to enteral nutrition, the pH of nutritional support, the timing of administration and the technique of tube placement were debated. Immunomodulating agents and hormonal manipulations may improve outcomes of critically ill patients, but still warrant further research before they can be recommended for routine clinical use.

Journal Article↗
PubMed2001

Physical activity and fat-free and fat mass by bioelectrical impedance in 3853 adults.

OBJECTIVE: To determine the effects of regular physical activity on body composition, as measured by bioelectrical impedance analysis (BIA), in a large Caucasian population of healthy subjects between 15 and 64 yr of age, and to observe the cross-sectional changes in body composition with increasing age. DESIGN: Cross-sectional comparison between sedentary and physically active adults (at least 3 h x wk(-1) at moderate or hard intensity level activity) during aging. SUBJECTS: A total of 3853 healthy adults (1036 sedentary and 1019 physically active men, and 1280 sedentary and 518 physically active women) between 15 and 64 yr of age. MEASUREMENTS: Height, weight, body mass index (BMI), and fat-free mass (FFM), fat mass, and % fat mass measured by 50-kHz BIA. RESULTS: Higher weight in older sedentary adults was due to a higher fat mass. In 55- to 64-yr-olds compared with 25- to 34-yr-olds, fat mass was 5.5 kg (P < 0.0001) higher in sedentary and 0.6 kg (P < 0.3) higher in physically active men, and 4.5 kg (P < 0.0001) and 2.0 kg (P < 0.04) higher in sedentary and physically active women, respectively. Physical activity was able to limit fat mass and weight gain in men over 25 yr of age and in women until 54 yr of age. Endurance type physical activity was not associated with increased FFM. For the same BMI, sedentary men and women have < 0.7 kg (P < 0.001) higher fat mass than physically active men and women. CONCLUSION: Therefore, the benefits of physical activity seem to include maintenance or prevention of an increase of BMI that in turn correlates with prevention of a fat mass increase for physically active subjects.

Adipose Tissue↗
PubMed2001

Management of catabolism in metabolically stressed patients: a literature survey about growth hormone application.

In the effort to improve the long-term outcome in critically ill patients, the utilization of anabolic agents, such as human recombinant growth hormone, has been proposed in order to reduce catabolism and improve nutritional status. A recent multicentre study regarding the use of human recombinant growth hormone in intensive care unit patients showed an unexpected increase in the mortality rate in human recombinant growth hormone-treated patients. This finding is in contrast with previous literature data reporting either no differences or an even lower mortality rate with the administration of human recombinant growth hormone. This review evaluates the possible reasons for this dramatic difference in outcomes between the multicentre study and the existing literature. Articles dealing with human recombinant growth hormone administration either in intensive care unit patients (n=26) or in postoperative patients (n=16) have been reviewed. Our analysis suggests that the low caloric intake given to patients enrolled in the multicentre study might have been inadequate to compensate for the hypermetabolism of these patients, and could not support the prolonged and delayed administration of high doses of human recombinant growth hormone. Whether the beneficial metabolic effects of human recombinant growth hormone translate into better clinical outcomes deserves further investigation. In addition, the careful selection of patients to be treated, and close monitoring of both the adequacy of caloric support and modality of human recombinant growth hormone administration would favour the safety of human recombinant growth hormone utilization in critical care settings.

Critical Illness↗
PubMed2001

(133)Xe SPECT cerebral blood flow study in a healthy population: determination of T-scores.

UNLABELLED: Dementia is becoming a major health problem as the population of the Northern Hemisphere ages. Early differential diagnosis between normal cognitive decline and dementia is particularly difficult. If psychometric evaluation can contribute to the diagnosis, quantitative cerebral functional imaging would play an important role. We therefore proposed, first, to constitute a normative dataset that could later be used to identify subjects at risk for neurodegenerative processes and, second, to describe the risk of abnormal global cerebral blood flow (gCBF) by defining categories based on the standardized cutoff scores of a young, healthy population (T-score). METHODS: Of a total of 203 healthy volunteers, 187 were included in the protocol, which included evaluation of medical history, neurologic and neuropsychologic status, and body composition; analysis of blood; and measurement of gCBF by means of (133)Xe SPECT. RESULTS: With ANOVA analysis using age and sex as between-subject factors and gCBF as a within-subject factor, a significantly higher gCBF was found in women than in men. In addition, a linear reduction as a function of age was observed for both sexes (-0.3%/y). T-score was determined for the 18- to 28-y-old age group, for whom gCBF was found to be 46.7 +/- 5.1 mL/min/100 g tissue in men and 49.0 +/- 5.0 mL/min/100 g tissue in women. The age-dependent decrease could thus be expressed in T-scores and, in the 29- to 38-y-old, 39- to 48-y-old, and >48-y-old age groups, averaged -0.63, -1.29, and -1.92, respectively, in men and -0.63, -0.83, and-2.40, respectively, in women. Cognitive performance, body composition, and blood analysis revealed the expected significant effects from sex and age. CONCLUSION: The large-scale reference database of gCBF measurements constituted from a healthy, well-controlled population enabled age and sex stratification, which showed significant differences between the sexes and a significant decline as a function of age. T-scores were determined and warrant further studies on the prospective identification of early dementia by (133)Xe SPECT in elderly individuals.

Adolescent↗
PubMed2001

[Early detection of protein-calorie malnutrition: a therapeutic asset].

In the industrialised countries, the sedentary life and the ageing process of the population, as well as the more frequent chronic diseases and heavy treatments, increase the incidence of protein-energy malnutrition (PEM). The insidious nature and harmful outcome of the PEM on the recovery process requires careful attention of the practitioner to the clinical signs of PEM. Their detection includes an anamnesis, anthropometric examinations, and assessments of the nutritional intakes and the impact of disease and medico-surgical treatments. However, the loss of muscle mass, which is the main indicator of the PEM, is often only assessed by the measurement of the body composition using bioelectrical impedance analysis. The advantage of this method is to distinguish fat-free mass, including muscle mass, from fat mass, when the loss of muscle is hidden by an increase of fat mass and/or body water. Using these different tools allows the practitioner to early detect PEM, to identify its causes, and to establish an appropriate nutritional schedule, in order to prevent from PEM or correct it.

Disease Progression↗