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Background: In less than two decades, the wireless telecommunications sector has grown dramatically. While a large part of the world's population is now equipped with technologies from this sector (mobile phone, wireless residential telephone, Wi-Fi…), little data is available to quantify the use of these technologies. The purpose of this article is to present a description of these uses among young people, a population particularly receptive to these new telecommunication facilities., Methods: As part of the MOBI-KIDS study, a prospective epidemiological case-control study, 288 participants aged 10 to 25 years and living in France were interviewed between March 2011 and March 2015 about their history of use of wireless telecommunication devices., Results: At the interview date, 84% of participants regularly used a mobile phone to make voice calls with an estimated cumulative duration of 45minutes per week. Of these users, 97% used the Short Message Service (SMS) sending function and 70% the data exchange functions. Regarding the use of other technologies, 88% of participants used Wi-Fi, for ten hours a week and 56% the wireless residential telephone. These uses, however, varied according to the sex and/or age of the subjects., Conclusion: The data draw a portrait of use, particularly quantitative, of the main wireless communication technologies in this young population. There is a gradual increase with age in the use of these technologies, while the age of initiation is at an increasingly early age., (Copyright © 2018 Elsevier Masson SAS. All rights reserved.)

In adolescents and young adults (AYA), cancers are rare but represent the third significant cause of death. The aim of this paper was to investigate epidemiological data and pathways of care of AYA in France. During the 2000-2008 period, overall age-standardized incidence rates (ASR) were 254.1/10 6 in 15-24-year-olds. The most frequently diagnosed cancers in male AYA were malignant gonadal germ-cell tumors and Hodgkin's lymphoma, and were melanoma, thyroid carcinoma and Hodgkin's disease in females. The ASR appeared stable over time. During the 2000-2004 period, the 5-year overall survival for all cancers was 81.8%, with differences between genders and age groups: 78.8% for males and 85.2% for females; 78.5% in 15-19-year-olds and 84.3% in 20-24-year-olds. Survival has significantly improved over time. During the 2006-2007 period, the pathways of care for French adolescent patients with cancer were heterogeneous: 82% were treated in an adult environment, 27% were included in clinical studies, and in 54% of cases the management decisions were taken in the context of a multidisciplinary team. Studies looking at management of AYA with cancer have shown a wide disparity and a lack of collaboration between adult oncologists and pediatric oncologist. An AYA cancer multidisciplinary interest group has been created to determine priorities and coordinate efforts to improve AYA cancer services and care., (Copyright © 2016 Société Française du Cancer. Published by Elsevier Masson SAS. All rights reserved.)

In France, cancer hits around 1700 children (0-14 years) each year. The age-standardized incidence rate for all cancers combined is 152 cases per million children per year, with a sex ratio of 1.2. In other terms, one child out of 440 develops a cancer before the age of 15 in industrial countries. The most frequent cancers were leukaemia (29%), embryonal tumours apart central nervous system (25%), central nervous system tumour (23%) and lymphoma (12%). The incidence varies between countries with higher overall rates in industrialized countries. These variations may reflect differences in diagnostic techniques or registration or in the distribution of possible risk factors. Five-year survival after childhood cancer has dramatically improved in the last 30 years, reaching yet 80%.

As part of a tender AP-HP Paris Hospitals, an assessment of the reliability record of five blood glucose monitoring systems (BGMSs) (Optium Xceed (Abbott), Contour TS (Bayer), One Touch Ultra (Lifescan), Stat Strip Xpress (Nova) and Accu Check (Roche) and an evaluation of their sensitivity to changes in hematocrit were conducted in 4 hospitals of Paris. In terms of inaccuracy, all BGMSs have submitted CV repetability under the limits of acceptability. One BGMS (Lifescan) presented a CV of reproducibility outside limit of acceptability (13.1%). The inaccuracy was measured by a comparison method on multiparameter analyser relative to the hexokinase method for two sites, the glucose oxidase for the two others. The coefficients of correlation varied from 0.8405 to 0.9303. However, according to both defined acceptability criteria (absolute value difference between the result acquired on analyzer and those determined with the BGMS), the percentage of results outside acceptability was above 20% for two BGMSs (Abbott and Lifescan). Similarly, a net effect of changes in hematocrit was observed on the results of those two BGMSs. BGMS Nova was the most reliable, because of the correction device for hematocrit and blank substractions owed to interferences. In terms of expertise, BGMSs Nova and Roche have been selected with the best analytical performance and practicability satisfactory. In the future, accreditation with standard NF/EN 22870 requested for point of care testing, will require a close collaboration between biologists and clinicians to establish a system of strict quality control to detect deviations of these BGMSs.

In order to build a continuous quality improvement approach for control of glucose meters in clinical divisions at Necker-Enfants Malades hospital, the analytical performances (precision and accuracy) of 2 glucose meters have been evaluated in our laboratory according to SFBC recommendations. Fifty-six heparinized whole blood specimens from patients and thirty-nine from healthy volunteers were analyzed on each of the two meters and compared to plasma glucose measurement on the Roche Hitachi 917 system. The correlation coefficient was 0.938 for Optium Xceed and 0.911 for One Touch Ultra. However, 14.7% and 18.9% of the results (n = 95) for respectively Optium Xceed and One Touch Ultra were discordant, i.e. higher than a 20% difference compared to reference blood glucose concentrations. Inaccuracy was more important for low glucose concentrations (< 5 mmol/L; 12/14 discrepant samples for Optium Xceed and 16/19 for One Touch Ultra). This data suggests a lack of accuracy, particularly for low glucose concentrations. Capillary blood glucose concentrations must therefore be interpreted with caution concerning the diagnosis of hypoglycemia and treatment of unstable patients. Moreover, quality control of glucose meters (blood glucose determinations concurrently at bedside and in the laboratory) is difficult to perform. It also raises questions about the responsibility of "point-of-care testing", an area still subject to discussion.

Adenine phosphoribosyltransferase (APRT, EC 2.4.2.7) deficiency is an enzymopathy of purine metabolism, which is inherited as an autosomal recessive trait. APRT is a salvage enzyme that normally catalyzes the conversion of adenine to adenosine monophosphate. APRT deficiency results in adenine accumulation with oxidation by xanthine dehydrogenase (XDH; EC 1.1.1.204) to 2,8-dihydroxyadenine (2,8-DHA) then excreted in urine. This compound is extremely insoluble and its crystallization can lead to stone formation and renal failure. The diagnosis of the disease is based on stone analysis by infrared spectroscopy or microscopic examination of urine, which may reveal typical 2,8-DHA crystals. The enzyme activity measurements in erythrocyte lysates will identify both homozygotes and heterozygotes for APRT deficiency. Molecular approach can identify mutations which are responsible of this inherited disease. Two types of deficit are commonly distinguished, depending on the level of residual APRT activity: type I, mainly observed in Caucasian subjects, in whom the enzyme activity is undetectable in homozygous patients and type II, found in Japanese patients who are able to form APRT but the enzyme activity is strikingly reduced because a low affinity for phosphoribosylpyrophosphate. The crystallization of 2,8-DHA and subsequent renal damages may be prevented with allopurinol therapy, a xanthine oxidase inhibitor. The role of the laboratory is crucial to detect APRT deficiency and to assess the efficacy of therapy, the objective being to avoid 2,8-DHA crystal formation.

Malignancies are rare young French adults but represent the third significant cause of death in the cohort of 15-24 years of age. The aim of this study was to investigate incidence and survival rates of French adolescents and young adults with cancer. All cases of cancer occuring over a 20-year period (1978-1997) in the cohort of patients aged 15 to 24, were obtained from nine population-based registries (10 % of the French population). Basal cell carcinomas of the skin were excluded. 1161 and 1884 cases were recorded in adolescents and young adults, respectively. Overall incidence rates (IR) were 161.4/10(6) in adolescents aged 15-19 years (M/F ratio = 1.3), and 252.6/10(6) in young adults aged 20-24 years (M/F ratio : 1.2). During the 1978-97 period, the IRs appeared stable over the years, +0.4 % [CI95 % = -2.3 ; +3.1] (p = 0.79) for adolescents and +1.7 % [CI95 % = -4.0 ; +7.3] (p = 0.57) for young adults. Five-year overall survival rates were 69.1 % [CI95 % = 66.4-71.8] for adolescents and 74.5 % [CI95 % = 72.3-76.7] for young adults. The 5-year survival rate for patients 15-24 years improved from 62.0 % (CI95 % = 57.5-66.5) in 1978-82 to 80.2 % (IC95 % = 77.7-82.8) in 1993-97. Noteworthy, results in adolescents and young adults are poor compared to the ones from their younger counterparts, especially in patients with acute lymphoblastic leukemia, non-Hodgkin lymphoma, Ewing's sarcoma, osteosarcoma, rhabdomyosarcoma, and astrocytoma. Further studies are warranted to elucidate whether these differences are due to intrinsic biological properties of the tumor or to differences in clinical practices in the two populations.

We assessed oxidative stress in 35 chronic renal failure under conservative treatment (CRF), 50 hemodialysed (HD) and 30 renal transplant (RT) patients, and 31 age- and sex-matched healthy subjects. Compared to controls, CRF patients exhibited significantly higher conjugated dienes (139 +/- 37 versus 121 +/- 22 micromol/l) and LDL oxidation (126 +/- 65 versus 99 +/- 46 micromol/l). Glutathione peroxidase activity was decreased in CRF and HD (5.31 +/- 2.46 and 5.39 +/- 2.32 versus 7.42 +/- 2.72 U/ml in healthy subjects). Superoxide dismutase activity was lower in HD (91 +/- 38 U/ml) and higher in RT patients (132 +/- 33 U/ml) than controls (116 +/- 30 U/ml). Plasma zinc concentrations were significantly decreased in CRF and HD patients and copper concentrations were significantly decreased in TPR. Plasma selenium levels were normal in the three groups of patients. Vitamin A was significantly increased, whereas vitamin E was normal in the 3 groups of patients compared to healthy controls. Total antioxidant status was increased in CRF and HD, but not in RT patients. Patients with cardiovascular disease showed increased serum copper, and significantly decreased glutathione peroxidase activity. This study revealed an oxidative stress in CRF and HD patients that may favour the development of cardiovascular diseases.

Introduction: Calcium oxalate is the leading cause of renal stones and is mainly due to hypercalciuria, hyperoxaluria and/or hypocitraturia. Citrate is considered to be an effective inhibitor of calcium oxalate crystallization and is therefore increasingly prescribed as maintenance therapy for patients with calcium stones, but no study has investigated the effect of urinary citrate levels on spontaneous calcium oxalate crystalluria in human urine. In this study, the authors examined the relationships between the calcium oxalate molar product, the urinary citrate concentration and weddellite (oxalate calcium dihydrate) crystalluria, the most frequent crystalline form of calcium oxalate in human urine., Material and Methods: Crystalluria analysis and calcium, oxalate and citrate assays were performed on a series of 10,222 first morning urine samples from 4,809 stone patients and 453 first morning urine samples from 317 control subjects. The frequency and characteristics of weddellite crystalluria were determined as a function of the calcium oxalate molar product (pCaOx) and urinary citrate concentration., Results: 1,940 urine samples (18.2%) presented weddellite crystalluria, which was pure in 1,378 urine samples from stone patients (13.5%) and 43 urine samples (9.5%) from controls (p < 0.05). The crystalluria rate in stone patients ranged from 4% for pCaOx < 1 (mmol/l)2 to 81.3% for pCaOx > or = 3 (mmol/l)2 (p < 0.0001). Over the same interval of pCaOx, weddellite crystalluria ranged from 1.5% to 72.2% in control subjects. An increase of urinary citrate excretion from 0.5 to 5 mmol/l significantly lowered the frequency of crystalluria from 32.4% to 10.1% for a pCaOx between 1 and 2 (mmol/l)2 (p < 0.0001) and from 63% to 27.9% for a pCaOx between 2 and 3 (mmol/l)2 (p < 0.001). For pCaOx values > or = 3 (mmol/l)2, urinary citrate excretion no longer significantly influenced the frequency of crystalluria. The number of crystals and aggregates and the maximum dimensions of aggregates were only influenced by the urinary citrate concentration when the pCaOx product was < 2 (mmol/l)2., Conclusion: The main determinant of the frequency and characteristics of weddellite crystalluria is the pCaOx molar product. The beneficial effect of the urinary citrate concentration on the frequency of crystalluria is observed for pCaOx values < 3 (mmol/l)2, but only for pCaOx values < 2 (mmol/l)2 for the characteristics of crystalluria such as the number and dimensions of crystals and aggregates. This means that therapeutic measures designed to increase urinary citrate concentrations can only be effective when pCaOx has been previously lowered by increased diuresis or specific reduction of urinary calcium and/or urinary oxalate levels.

Incidence of cardiovascular events is higher in hemodialysis (HD) patients than in general population. Oxidative stress represents a major specific risk factor of accelerated atheroma particularly in association with inflammation and malnutrition. The aim of our study is to evaluate a simple test of lipid peroxidation measurement using the "Free Oxygen Radical Monitor" (FORM) (Callegari, Italy). The results obtained in HD patients were compared to standard oxidative stress markers, such as thiobarbituric acid reacting substances, carbonyls and vitamin E in plasma, and glutathione, oxidized to reduced form ratio, in erythrocytes. In conclusion, the FORM system presents no sufficient sensibility and specificity to determine oxidative stress in HD patients.

Crystalluria is a marker of urine supersaturation present in both normal and pathological conditions. Indeed, nature and characteristics of the spontaneous crystalluria are of clinical interest for detecting and following biological disorders involved in renal diseases. Method. Crystalluria examination should preferably be performed on first morning urine or fresh fasting voiding samples by polarised microscopy in a Malassez cell. Urine samples must be stored at 37 degrees C or at room temperature and examined within two hours following voiding. Results and discussion. Crystalluria should be interpreted according to various criteria: 1) chemical nature of crystals for abnormal crystals such as struvite, ammonium urate, cystine, dihydroxyadenine, xanthine or drugs; 2) crystalline phase of common chemical species as calcium oxalates, calcium phosphates and uric acids; 3) crystal morphology (calcium oxalates); 4) crystal size (calcium oxalates); 5) crystal abundance (calcium oxalates, calcium phosphates, uric acids, cystine); 6) crystal aggregation (calcium oxalates); 7) frequency of crystalluria assessed on serial first morning urine samples, a very useful tool for long-term surveillance of patients. Within calcium oxalate crystalluria, presence of whewellite is a marker of elevated oxalate concentration (urine oxalate > 0.3 mmol/L); a crystal number > 200/mm 3 is highly suggestive of heavy hyperoxaluria of genetic or absorptive origin. Predominant weddellite crystalluria is most often indicative of an excessive urine calcium concentration (> 3.8 mmol/L); a dodecahedric aspect of the crystals is a marker for heavy hypercalciuria (> 6 mmol/L) while an increased crystal size (>or= 35 microm) is indicative of simultaneous hypercalciuria and hyperoxaluria. Calculation of the global crystal volume, especially when applied to calcium oxalates or cystine, is a clinically useful tool for the monitoring of patients suffering from primary hyperoxaluria or cystinuria. Lastly, presence of crystalluria in more than 50% of serial first voided morning urine samples is in our experience the most reliable biological marker for detecting the risk of stone recurrence in lithiasic patients. Conclusion. Crystalluria examination is an essential laboratory test for detecting and following pathological conditions, which may induce renal stone disease or alter kidney function due to urine crystals., (Copyright John Libbey Eurotext 2003.)

Introduction: More than ten per cent of stones are associated with a urinary tract abnormality. To verify whether the malformation influences stone composition, we studied the composition of stones observed in fifteen urological abnormalities., Material and Method: This study is based on 1,461 stones associated with a clearly defined malformation analysed by infrared spectroscopy plus 402 bladder stones in men with benign prostatic hyperplasia., Results: In this series of 1,863 abnormalities, 732 (39.3%) involved the kidney, 561 (30.1%) involved the ureter and 570 (30.6%) involved the lower tract. Whewellite stones were predominant in all renal abnormalities with the exception of cysts, which were mainly associated with uric acid. The main differences concerned the second constituent: weddellite in horseshoe kidneys, carbapatite in Cacchi-Ricci disease and caliceal abnormalities. Struvite was uncommon (<10%). Whewellite was the main component in ureteric abnormalities except for megaureter and reflux in which carbapatite was predominant. Struvite was present in 10% to 30% of stones. Vesicourethral abnormalities were accompanied by calcium and magnesium phosphate stones (90% of cases), and struvite was present in 58% to 90% of cases. The exception to this general rule was bladder stones associated with benign prostatic hyperplasia, in which the main component was uric acid., Conclusion: Significant differences in stone composition were observed as a function of anatomical abnormalities reflecting the fact that some abnormalities add infectious or metabolic risk factors to anatomical factors.

The knowledge of the epidemiology of cancer in childhood is relevant of a strict methodology allowed by the activation of population-based specific registries, case-control and cohort studies. Descriptive epidemiology is a mean of survey and of public health, while analytic epidemiology contributes to define the role of genetic and environmental factors, along with their interaction. The collected data help indirectly to improve the care of the child with cancer and to a better understanding of the carcinogenesis.

Analysis of 22,510 urinary calculi between January 1991 to July 2000 performed by infrared spectroscopy allows for separation of drug-induced urolithiasis into two categories: first, the drugs physically embedded in the stone (n = 238; 1.0 per cent), notably indinavir monohydrate (n = 126; 52.9 per cent), followed by triamterene (n = 43; 18.1 per cent), sulphonamides (n = 29; 12.2 per cent) and amorphous silica (n = 24; 10.1 per cent); second, the category of metabolic nephrolithiasis induced by drugs (n = 140; 0.6 per cent), involving mainly calcium and vitamin D supplementation (n = 56; 40.0 per cent) and carbonic anhydrase inhibitors (n = 33; 23.6 per cent). Composition of the stone depended not only on the inducer drug but also on the metabolic state of the patient. Today, drug-induced stones comprise about 1.6 per cent of all calculi in France. Physical analysis and therapeutic history recall of such patients are the keys to diagnosis. Medical care is based on drug avoidance or dose adjustment with increased diuresis and, if necessary, change in urinary pH.

Objective: High urine volume is known to be an effective measure for preventing stone recurrence. However, only few studies have investigated its effects on crystalluria and spontaneous passage of calculi. The aim of the study was to assess the effects of high diuresis on stone expulsion and recurrence., Patients and Methods: 219 patients were consulting for a first stone episode in Urology units in the Mostaganem area between September 1996 and December 1999. All stones were under 6 mm in size. The patients were divided in two groups: group I included 129 patients (68 males, 61 females) who agreed to be on a high water intake, at least 3 liters per day, over a two months period and to be followed periodically by crystalluria examination in the first morning urine; group II included 90 patients (63 males, 27 females) who declined diuresis advice and urine collection for crystalluria examination. First morning urine collected in patients of group I were examined before (2.95 voidings per subject) and while on diuresis course (2.84 voidings per subject). For each sample, the urine pH was measured and crystals were looked for by polarizing microscopy. Stones spontaneously passed were collected and analyzed by infrared spectroscopy. Group II represented the control group for stone passing and recurrence., Results: Crystalluria was present in 52.4% of urine samples before starting diuresis and decreased at 22.9% of urine samples on high diuresis. Mean pH value increased from 5.73 +/- 0.46 before to 6.09 +/- 0.47 (p < 10-6) while on diuresis course in males and from 5.8 +/- 0.68 to 6.24 +/- 0.66 in females (p < 10-6). The most frequent crystalline species was weddellite. Over the study period, 98 patients (76%) in group I and only 13 patients (14.4%) in group II passed stones spontaneously (p < 10-6 contre group I). No stone recurrence was observed in group I while 37.8% of patients in group II presented at least one stone recurrence (p < 10-7)., Conclusion: A high diuresis is an effective measure (1) to make easier the passing of stone under 6 mm in size; (2) to reduce the occurrence of crystalluria; (3) to reduce significantly, because of its favourable effect on urine pH, the formation of pH-dependent crystalline phases, thus decreasing heterogeneous nucleation process of calcium oxalate and stone recurrence.

Unlabelled: The successful fragmentation of kidney stones by means of extracorporeal shock wave lithotripsy partly depends on stone composition. In case of incomplete or coarse fragmentation, multiple urological procedures following ESWL may be necessary for removal of obstructive fragments. It is difficult to be sure that a given stone will be successfully destroyed. X-ray examinations before treatment are useful to classify calculi as calcium stones or not. Nevertheless, such investigations are often not sufficient to identify the main crystalline phases which form the stone and that can make it either resistant or friable to ESWL., Objective: The aim of this study was to compare crystalluria and stone composition in patients with kidney calculi., Material and Methods: Seventy-five untreated patients (54 males, 21 females) were included. Their first morning urine was collected three days before surgical removal of the stone. Urine samples were kept at 4 degrees C during 48 hours before examination., Results: Crystalluria occurred in 97.3% of urine specimens. Weddellite was the most frequent crystalline species found in urine (66.2%), followed by carbapatite (33.1%) and whewellite (23.1%). When compared to stone composition, crystalluria was mainly made of weddellite in urines from 68% of patients with weddellite-rich calculi. Stones from patients presenting with whewellite crystals in urine were mainly composed of whewellite in 88.9% of cases. Struvite stones were associated with struvite and carbapatite crystalluria in 85.7% of cases., Conclusion: Crystalluria studies could be of clinical interest to predict the main crystalline phase of calcium-containing stones in order to define the best procedures for stone removal.

The presence of colonic tumor cells in the circulation may predict colorectal carcinoma recurrence and metastases. We have developed a highly sensitive nested RT-PCR assay, with primers derived from the cytokeratin 20 (CK20) and the carcinoembryonic gene CGM2, to detect occult microdisseminated enterocytes in blood of colorectal cancer patients. Among 82 healthy controls analyzed, 40.2% (33/82) have a positive expression of CK20 mRNA which is not statistically different from the 45.5% (15/33) of positive results found in colon cancer patients. This sensitive method may detect non-tissue specific constitutive low level (illegitimate) expression of CK20 mRNA in peripheral nucleated blood cells (PNBC) of a significant number of healthy control as well as in a number of normal bone marrow. The low specificity of this assay therefore hampers its value to detect blood colon cancer dissemination. In 47 patients with colorectal carcinoma, CGM2 primers detected circulating enterocytes in 25 of them (53%). In disseminated Dukes' stage C disease patients, 17 out of 29 (59%) were found positive whereas in localized adenocarcinoma (Dukes's stage A and B), CGM2 primers detected enterocytes in 44% suggesting that an hematogenous spillage of colonic cells may be a relatively early event in colon cancer. None of the patients suffering from benign colonic pathologies or from diverticulitis were found positive for this assay. The analysis of 56 healthy individuals without known colorectal cancer, of 20 non-colorectal cancer patients and of 6 normal bone marrows provide evidence that this assay is highly specific and may predict an hematogenous spread of colonic cells in patients with organ-confined disease. Nevertheless, the clinical significance of enterocyte detection and the potential applications of this molecular tool merit longer term follow-up.

We analyzed a series of 61 stones from children aged 3 to 14 years old using Fourier transform infrared spectroscopy. The calculi were collected from urology departments of the University Hospitals of Oran, Sidi-Bel-Abbès and Mostaganem in West Algeria. This series is the first investigation concerning the composition of stones in children based on infrared analysis. Calculi were more frequent in males (75.4%) and mainly localized in the bladder (55.8%). Upper urinary tract calculi were more frequent in children over the age of 10 years, and the sex ratio was about 1. Calcium oxalate monohydrate was present in 70.5% of stones and was the main component in 50.8% of cases both in whole stones and nuclei. In contrast, calcium oxalate dihydrate was the main component in only 9.8% of calculi although it was present in 75.4% of stones. Ammonium urate was detected in 29.5% of stones and was always the main component of nuclei. Uric acid, observed in 31.1% of calculi, was the major constituent in 14.7% of stones and 19.7% of nuclei. Magnesium ammonium phosphate was observed in 24.6% of stones as a consequence of urinary tract infection by urea-splitting bacteria. Our observations emphasized that the anatomical location of stone and their composition were in accordance with those previously reported in other countries.

Objectives: The aim of this study was to study the effect of sorbitol on sodium, water and calcium fluxes in rat ileum in situ perfused loop., Methods: Net water, sodium and calcium fluxes, and one-way calcium fluxes were measured in situ in a perfused rat ileal loop in the presence of varying concentrations of sorbital., Results: High concentrations of sorbitol in perfused ileal solution induced a decrease of sodium and water fluxes and a concomitant increase of lumen to mucosa calcium flux associated with an increase of net calcium flux, using a solution containing either 8.0 or 1.25 mM calcium. These effects were independent of absolute initial values of water and sodium fluxes. They were observed in the presence of 25 mM glucose, 10 mM theophyllin or after treatment of rats with dexamethasone., Conclusion: These effects of sorbitol on calcium flux are not compatible with a stimulation of paracellular pathway. By contrast, they can be explained by a stimulation of transcellular calcium pathway in ileum associated with the hyperpolarisation of the cells induced by the decrease of luminal sodium concentration necessary in the presence of sorbitol to maintain unchanged osmolarity of perfusate.

The method selected by the SFBC (Société française de biologie clinique) is derived from the colorimetric reaction of creatinine with alkaline picrate, measured kinetically, without any pretreatment step. The key parameters of the reaction determining the quality of the results are studied, with special regard to samples including known interferents. The aims of the study were to gain an optimal analytical sensitivity and to reduce main interferences (acetoacetate, bilirubine, glucose, protein) which plague the Jaffé reaction, through a comprehensive study of the reagents, of their concentrations and of the analytical procedures. The selected concentrations (in the test) are: 150 mmol/L sodium hydroxide, 10 mmol/L picric acid and 2 g/L sodium dodecyl sulfate. Ten millilitres of a BRIJ solution (30% volvol) are added to the reagent. The operating procedures are as follow: sample ratio 0.07 to 0.08; wavelength 505 to 510 nm; temperature 37 degrees C; incubation of the specimen with the alkaline reagent 5 mn (at least), before starting the reaction with picric acid. A seric calibrator is recommended. The first measurement is taken 20 to 40 s after starting the reaction. Total measurement time is 120 to 150 seconds.