Adult human spinal cord harbors neural precursor cells that generate neurons and glial cells in vitro.

Adult human and rodent brains contain neural stem and progenitor cells, and the presence of neural stem cells in the adult rodent spinal cord has also been described. Here, using electron microscopy, expression of neural precursor cell markers, and cell culture, we investigated whether neural precursor cells are also present in adult human spinal cord. In well-preserved nonpathological post-mortem human adult spinal cord, nestin, Sox2, GFAP, CD15, Nkx6.1, and PSA-NCAM were found to be expressed heterogeneously by cells located around the central canal. Ultrastructural analysis revealed the existence of immature cells close to the ependymal cells, which display characteristics of type B and C cells found in the adult rodent brain subventricular region, which are considered to be stem and progenitor cells, respectively. Completely dissociated spinal cord cells reproducibly formed Sox2(+) nestin(+) neurospheres containing proliferative precursor cells. On differentiation, these generate glial cells and gamma-aminobutyric acid (GABA)-ergic neurons. These results provide the first evidence for the existence in the adult human spinal cord of neural precursors with the potential to differentiate into neurons and glia. They represent a major interest for endogenous regeneration of spinal cord after trauma and in degenerative diseases.

Evaluation of a capillary zone electrophoresis system versus a conventional agarose gel system for routine serum protein separation and monoclonal component typing.

Capillary zone electrophoresis of serum proteins is increasingly gaining impact in clinical laboratories. During 2003, we compared the fully automated capillary electrophoresis (CE) system from Beckman (Paragon CZE 2000) with the method agarose gel electrophoresis Sebia (Hydrasis-Hyris, AGE). This new study focused on the evaluation of analytical performance and a comparison including 115 fresh routine samples (group A) and a series of 97 frozen pathologic sera with suspicion of monoclonal protein (group B). Coefficients of variation (CVs %) for the five classical protein fractions have been reported to be consistenly < 9% in within-run and < 10% in between-run imprecision studies with the Paragon 2000 system. The results of the comparison study (group A) demonstrated a good correlation between the CE system and AGE, except for beta-globulin (r = 0.65). Among the 97 pathologic serum samples (group B), there were 90 in which we detected a monoclonal protein by immunofixation (IF) (immunosubtraction (IS) was not used). AGE and Paragon 2000 failed to detect 7 and 12 monoclonal proteins, respectively, leading to a concordance to 92% for AGE and 87% for Paragon 2000 for identifying electrophoretic abnormalities in this group. Beta-globulin abnormalities and M paraprotein were well detected with Paragon 2000. Only 81% (21 vs 26) of the gammopathies were immunotyped with IS by two readers blinded to the IF immunotype. The Paragon 2000 is a reliable alternative to conventional agarose gel electrophoresis combining the advantages of full automation (rapidity, ease of use and cost) with high analytical performance. Qualified interpretation of results requires an adaptation period which could further improve concordance between the methods. Recently, this CE system has been improved by the manufacturer (Beckman) concerning the migration buffer and detection of beta-globulin abnormalities.

The risk of cardiac injury during laparoscopic fundoplication: cardiac troponin I and ECG study.

BACKGROUND: Myocardial trauma has been described during gastroesophageal reflux laparoscopic surgery, in association with the proximity of cardiac structures. In addition, specific haemodynamic changes induced by CO2 pneumoperitoneum could exacerbate perioperative cardiac complication even in patients without cardiac risk factors. The aim of this study was to evaluate the influence of gastroesophageal reflux laparoscopic surgery on the perioperative ECG, cardiac troponin I and myocardial enzyme changes. METHODS: Forty-two ASA I-II patients without ischaemic heart disease or combined double-risk factors were studied. Automated ST segment analysis was used intraoperatively. ECG, plasma myocardial enzyme and cardiac troponin I concentrations were reported on arrival in the recovery room (HO), 4 h (H4) and 24 h (H24) postoperatively. RESULTS: Intraoperative ST segment changes occurred in two patients: the first during a hypotensive episode (MAP<55 mmHg; 3/42 patients) and the second during a hypertensive episode (MAP >110 mmHg; 3/42 patients). One case of intraoperative subcutaneous emphysema occurred without ST disturbance. One case of pneumothorax was observed at H0-H4 in another patient without clinical symptoms. Cardiac troponin I and CK-MB were not increased postoperatively. Transaminase concentrations increased (2-fold normal values) in 26/42 patients. In these 26 patients, 7 experienced 5-fold isolated transaminase increase, associated with left hepatic artery section. CONCLUSION: According to perioperative ECG changes and/or specific cardiac troponin I measurements, we did not identify specific myocardial damage following gastroesophageal reflux laparoscopic surgery. Unexpectedly, the incidence of hepatic cytolysis was frequent (62%) and has not previously been reported in the literature.

Serum leptin is associated with the perception of palatability during a standardized high-carbohydrate breakfast test.

Leptin is an adipocyte-derived signalling molecule which plays a key role in the regulation of body weight and energy expenditure. Since its involvement in human eating behaviour is still poorly understood, we investigated whether the perception of palatability of food was related to fasting serum leptin levels. Twenty-six non-diabetic subjects, six men and twenty women of widely ranging age and body mass index, performed a standardized high-carbohydrate breakfast test. Palatability was evaluated with a visual analogue scale, body composition by bioelectrical impedance, serum leptin and plasma insulin by radioimmunoassay. Palatability was correlated to fasting serum leptin levels independently of body mass index, body fat mass and percentage of body fat (P<0.01). No significant relation was observed with peaks of insulinaemia, integrated concentrations of insulin or insulin resistance indices. A stepwise regression analysis indicated that serum leptin gave the strongest predictive association with palatability. These results suggest that the leptin system may be involved in the regulation of human eating behaviour in relation to the perception of palatability of food.

Prognostic value of myocardial lactate dehydrogenase subunit ratio in heart transplant recipients.

BACKGROUND: Allograft coronary artery disease (CAD) is a major long-term complication in heart transplant recipients. Unfortunately, methods for early estimation of the likelihood of development of the disease are not currently available. Lactate dehydrogenase (LDH) is composed of heart and muscle subunits. The prevalence of these subunits in LDH isoenzymes (LDH1 through LDH5) is an accurate indicator of myocardial metabolism and allows indirect estimation of oxygen availability to cardiocytes. This study investigated the prognostic value of myocardial LDH composition for the occurrence of morbid events in patients with severe allograft CAD. METHODS: Eighty-eight heart transplant recipients were followed up for a median of 4.3 years. The isoenzymes of LDH and the ratio of the heart and muscle subunits (H/M) were determined in 526 endomyocardial biopsy samples. RESULTS: Eleven patients (12%) died from allograft CAD during follow-up. They had significantly lower H/M ratios compared with event-free patients, with clear differences as early as 6 months after operation. A threshold value of 2.75 was derived from receiver operating characteristic curve analysis. Patients showing H/M values < or =2.75 had a significantly higher mortality rate than did those with higher values (p=.0003). Importantly, the H/M ratio emerged as the most powerful independent prognostic factor of death by allograft CAD (p=.001) in a multivariate model. CONCLUSIONS: Poor myocardial aerobic metabolism estimated through low H/M values was highly predictive of cardiac death resulting from severe allograft CAD. Analysis of LDH isoenzyme profile in routine endomyocardial biopsies might be of clinical value.

Study of calcium oxalate crystalluria on renal and vesical urines in stone formers and normal subjects.

OBJECTIVE: The aim of this study is to compare vesical and renal calcium oxalate crystalluria in an attempt to correlate crystal formation with chemical composition and calcium oxalate saturation of renal urine. MATERIAL AND METHODS: Urine specimens were directly collected from the bladder and the kidney, of 11 stone formers and 11 control subjects under general anesthesia. The type of crystals present in urine as well as their size, number by cubic millimeter and state of aggregation were determined. In addition, calcium, magnesium, sodium, chloride, phosphate, citrate, oxalate, pyrophosphate and uric acid were measured in order to evaluate the calcium saturation status (EQUIL V program). RESULTS: Calcium oxalate crystals were detected in 3 stone formers (27%) and 2 control subjects (18%) in vesical urine and in 4 stone formers (36%) and 3 control subjects (27%) in renal urine. Only 2 stone formers presented with simultaneous renal and vesical crystalluria. Subjects of the two groups with and without renal crystalluria were compared in terms of chemical composition and calcium oxalate saturation of renal urine. Crystalluric subjects (n = 7) had significantly higher uricosuria (p = 0.02), calciuria (p = 0.04), magnesiuria (p = 0.04) and calcium oxalate molar product (p = 0.05) than noncrystalluric (n = 15); calcium oxalate saturation was similar (p = 0.5). CONCLUSIONS: Beyond theorical considerations on lithogenesis, our observations and in particular the apparent discrepancy between renal and vesical crystalluria pose the problem of the clinical interest of the evaluation of calcium oxalate crystalluria based on freshly voided urine in the assessing the lithogenic risk or in the follow-up of patients who are particularly prone to stone recurrence.

Double-J ureteric stent encrustations: clinical study on crystal formation on polyurethane stents.

OBJECTIVE: To evaluate the crystalline composition of encrustations on double-J ureteric stents in order to prevent their formation on the base of urolithiasis prophylaxis. PATIENTS: 40 patients had a polyurethane double-J ureteric stent inserted between June 1994 and March 1995. Group 1 comprised 22 stone formers whose stents were placed in support of endourological treatment or extracorporeal shock wave lithotripsy of renal or ureteric calculi. Group 2 comprised 18 patients whose stents were inserted for advanced and obstructive malignancy (n = 8) or as an adjunct to reconstructive surgery or endourological techniques (n = 10). After removal, stents were examined for encrustation and obstruction. A biochemical semiquantitative analysis was performed for deposits > 5 mg, and smaller sediments were examined with a polarizing optical microscope. RESULTS: The incidence of encrustation was significantly higher (p = 0.009) for stone formers. In addition, in this group indwelling times of encrusted and obstructed stents were significantly shorter (p = 0.03 and 0.02, respectively). No particular relationship was found between the incidence of encrustation and indwelling times for stone formers. Conversely, for patients without urolithiasis, indwelling times were significantly longer for encrusted or obstructed stents than for unaffected ones (p = 0.05 and 0.02, respectively). Biochemical and optical analyses of encrustations mainly revealed calcium oxalate, calcium phosphate and ammonium magnesium phosphate. Calcium oxalate was the main crystalline phase, especially in the absence of urinary infection. CONCLUSION: Calcium oxalate represents the principal component of double-J ureteric stent encrustations. Thus, prophylaxis of encrustation may consist of preventive measures usually applied in cases of recurrent idiopathic calcium oxalate urolithiasis.

[Indicators of the risk of calcium oxalate urinary calculi: comparative study of the Parks' and Tiselius' indices, urinary citrate/calciuria ratio, and morning crystalluria]. / Les indicateurs du risque lithogène oxalo-calcique urinaire: Etude comparative des indices de Parks et de Tiselius, du rapport citraturie/calciurie et de la cristallurie matinale.

Despite the progress in basic research, the precise assessment of the risk of calcium oxalate urinary stones and the detection of patients at particular risk of recurrent stones are often problematical. A population of 55 renal stone patients and 50 controls served as a basis for various comparative studies of Parks' index, Tiselius' index, the urinary citrate/urinary calcium ratio and the morning calcium oxalate crystalluria. Parks' index and the urinary citrate/urinary calcium ratio were highly discriminant, in contrast with Tiselius' index and crystalluria, which were statistically comparable in the 2 groups. A close correlation was observed for the 3 versions of Tiselius' index, which estimates diuresis, but no particular correlation was detected between crystalluria and the other parameters studied. Parks' index and the urinary citrate/urinary calcium ratio are potentially adapted to the detection and monitoring of renal stone patients at risk of recurrence. On the other hand, the various Tiselius' indices can be essentially used to evaluate urinary calcium oxalate oversaturation and possibly to control treatments interfering with this parameter. The formula simply based on diuresis, and the 24-hour urinary calcium and oxalate excretion (CaO.71.Ox.V-1.2) appears to be sufficient for this purpose. The absence of correlation between crystalluria and the other potential indicators of lithogenic risk raises the problem of their respective validity as well as the possible prevalence in the crystallization process of the powerful inhibitors which are currently unidentified, but probably macromolecular.

Evaluation of the risk of stone formation: study on crystalluria in patients with recurrent calcium oxalate urolithiasis.

OBJECTIVE: The aim of this study was to determine the usefulness of the morning calcium oxalate crystalluria in detecting stone formers particularly prone to recurrence. METHODS: Over a 24-hour period of urine collection, the morning calcium oxalate crystalluria was evaluated as well as the risk of stone formation, established with Tiselius and Parks indices, for 25 recurrent stone formers (group 1) and 25 normal controls (group 2). RESULTS: Morning crystalluria (type, size, number/ml and state of aggregate) and the Tiselius index were comparable in the two groups. Conversely, calciuria as well as the citrate/ calcium ratio and the Parks index varied significantly for stone formers and normal controls. No particular correlation appeared between crystalluria and indices of Tiselius and Parks, calciuria, calcium-oxalate product or calcium/ oxalate and citrate/calcium ratios. CONCLUSIONS: Morning calcium oxalate crystalluria does not enable an efficient characterization of recurrent stone formers. Its discordance with others potential indicators of the risk of stone formation poses the problem of their respective validity and evokes the prevalence of still unknown inhibiting agents in the phenomenon of crystallization.

Myocardial lactate dehydrogenase subunit ratio in cardiac allograft recipients.

BACKGROUND: Allograft coronary artery disease (CAD) is a major long-term complication in heart transplanted patients. However, the metabolic basis of allograft CAD remains to be fully elucidated. We analyzed the lactate dehydrogenase heart (H) and muscle (M) isoenzyme pattern in endomyocardial biopsy specimens and the evolution of the H/M ratio to test whether changes in this ratio could be the earliest manifestation of allograft CAD. METHODS: Twenty-four heart transplant recipients were followed up for 12 months. Endomyocardial biopsy was performed at 1, 2, 3, 6, and 12 months after transplantation. Lactate dehydrogenase 1 through 5 isoenzymes were separated by electrophoresis, and the H/M ratio was calculated. Two groups of patients were identified: group 1 (n = 20), patients without allograft CAD; and group 2 (n = 4), patients with poor outcome (three deaths, 1 case of low cardiac output) and angiographic and histologic evidence of allograft CAD. RESULTS: Both groups had similar H/M baseline values. The H/M ratio was higher (p = 0.01) in group 1 at 6 months (3.48 +/- 0.64 versus 2.17 +/- 0.43) and 12 months (3.76 +/- 0.92 versus 2.18 +/- 0.45) when compared with group 2. The H/M ratio increased from 2.78 +/- 0.89 at 1 month to 3.76 +/- 0.92 at 12 months (p = 0.02) in group 1 and decreased in group 2 (2.86 +/- 0.49 versus 2.18 +/- 0.45; not significant). CONCLUSIONS: Changes in H/M ratio reflect an anaerobic shift in the lactate dehydrogenase isoenzyme composition and can be taken as an early indicator of allograft CAD.

Idiopathic calcium oxalate urinary lithiasis: usefulness of Parks' and Tiselius' indices in the evaluation of the risk of stone formation.

Different indices of the risk of urinary calcium oxalate crystallization were compared to determine their usefulness in detecting the stone-formers particularly prone to recurrence. Urine volume and calcium, oxalate, citrate, magnesium or creatinine were determined in 55 patients presenting with an idiopathic calcium oxalate urolithiasis, as well as in 50 control subjects. On 24-hour urine samples, these elements allowed for the calculation and comparison of different indices of lithogenous risk as proposed by Parks and Tiselius. Both Parks' indices and the urinary citrate-calcium ratio varied significantly between the two groups, but conversely Tiselius' indices were statistically comparable. The three Tiselius' indices taking the 24-hour urine volume into account were also strongly correlated. Parks' index and the urinary citrate-calcium ratio are highly discriminating and potentially relevant to select the stone-formers with a high risk of relapse. Tiselius' indices basically reflect urinary calcium oxalate saturation, and can only be used clinically to control the treatment interfering with this. In this respect, the formula based simply on urine volume, calcium and oxalate over 24 h (Ca0.71.Ox.V-1.2) appears to be sufficient.

Circadian variations in the risk of urinary calcium oxalate stone formation.

OBJECTIVE: To evaluate the circadian fluctuations in the risk of urinary calcium oxalate stone formation with regard to critical periods of crystallization. PATIENTS AND METHODS: Over a given time period, the Tiselius index depends on urine volume and urinary excretion of oxalate, calcium, citrate and magnesium. This crystallization potential was evaluated during three successive periods spread over 24 h for 25 recurrent stone-formers aged 16-76 years (mean 50) and 25 control subjects aged 27-71 years (mean 44). RESULTS: There was no significant difference in the value of the Tiselius index for all equivalent time periods in both groups of patients. The minimum value was recorded in the afternoon and the circadian pattern of the index illustrated the predominant importance of urinary output in its determination. Morning urinary concentrations and excretions of citrate, and nocturnal levels of magnesium were significantly higher in the stone-formers when compared with the control subjects. CONCLUSION: The lithogenic risk for calcium oxalate stones was maximal at the end of the night or during the early morning, when urinary output was minimal. This circadian study revealed abnormalities that are not apparent from non-fractionated 24 h urine samples, and which were potentially relevant to therapy.

Urinary calcium oxalate saturation in 'stone formers' and normal subjects: an application of the EQUIL2 program.

OBJECTIVE: To produce an index of lithogenic risk which identifies patients at risk of stone recurrence and facilitates the monitoring of prophylactic treatments. PATIENTS AND METHODS: The EQUIL2 program provides an evaluation of the state of urinary saturation, particularly of calcium oxalate, based on the pH and total concentrations (mmol/l) of sodium, potassium, calcium, magnesium, uric acid, chloride, ammonium, citrate, phosphate, sulphate, oxalate, pyrophosphate and carbon dioxide. The morning urinary calcium oxalate saturation coefficient was thus calculated for 30 stone-formers (Group 1) and 30 normal control subjects (Group 2). RESULTS: Urine from the majority of individuals was saturated, with no significant difference between the two groups. There appeared to be a correlation between the state of saturation and the urinary calcium oxalate molar product in both stone-formers (r = 0.931) and controls (r = 0.914). CONCLUSION: In future studies on urinary calcium oxalate saturation, it should be possible to supplement the sophisticated coefficient determined by the EQUIL2 program with the molar product, except in cases where monitoring therapies have little or no effect on urinary oxalate or urinary calcium levels.

Bioluminescence: an improvement in the enzymatic assay of dehydroepiandrosterone sulfate in biological fluids.

Dehydroepiandrosterone sulfate (DHEAS) determination in biological fluids was carried out by enzymatic hydrolysis and conversion into estrogens [estrone (E1) and estradiol (E2)] by the multienzyme system of human placental microsomes. The enzymatic complex consists of sulfatase, 3 beta-hydroxysteroid oxido reductase and 5en----4en isomerase which converts DHEAS into androstenedione (A); the latter component is further converted into estrogens by the aromatase. The resulting estrogens were determined from the NADH formed by the transhydrogenation reactions of human placental dehydrogenase. NADH was measured by bioluminescence. As little as 4 pg was assayable by this rapid enzymatic method, with a coefficient of variation of 8%. The results are in good agreement with radioimmunoassay and the method is suitable for routine use.