[Biological markers for the status of vitamins B12 and D: the importance of some analytical aspects in relation to clinical interpretation of results]. / Marqueurs biologiques des statuts vitaminiques B12 et D: aspects analytiques d'importance clinique.

Biological markers for the status of vitamins B12 and D: the importance of some analytical aspects in relation to clinical interpretation of results When vitamin B12 deficiency is expressed clinically, the diagnostic performance of total cobalamin is identical to that of holotranscobalamin II. In subclinical B12 deficiency, the two aforementioned markers perform less well. Additional analysis of a second, functional marker (methylmalonate or homocysteine) is recommended. Different analytical approaches for 25-hydroxyvitamin D quantification, the marker of vitamin D deficiency, are not yet standardized. Measurement biases of up to +/- 20% compared with the original method used to establish threshold values are still observed.

Sensitive determination of D-lactic acid and L-lactic acid in urine by high-performance liquid chromatography-tandem mass spectrometry.

D-lactic acid in urine originates mainly from bacterial production in the intestinal tract. Increased D-lactate excretion as observed in patients affected by short bowel syndrome or necrotizing enterocolitis reflects D-lactic overproduction. Therefore, there is a need for a reliable and sensitive method able to detect D-lactic acid even at subclinical elevation levels. A new and highly sensitive method for the simultaneous determination of L- and D-lactic acid by a two-step procedure has been developed. This method is based on the concentration of lactic acid enantiomers from urine by supported liquid extraction followed by high-performance liquid chromatography-tandem mass spectrometry. The separation was achieved by the use of an Astec Chirobiotic™ R chiral column under isocratic conditions. The calibration curves were linear over the ranges of 2-400 and 0.5-100 µmol/L respectively for L- and D-lactic acid. The limit of detection of D-lactic acid was 0.125 µmol/L and its limit of quantification was 0.5 µmol/L. The overall accuracy and precision were well within 10% of the nominal values. The developed method is suitable for production of reference values in children and could be applied for accurate routine analysis.

Evidence for catabolic pathway of propionate metabolism in CNS: expression pattern of methylmalonyl-CoA mutase and propionyl-CoA carboxylase alpha-subunit in developing and adult rat brain.

Methylmalonyl-CoA mutase (MCM) and propionyl-CoA carboxylase (PCC) are the key enzymes of the catabolic pathway of propionate metabolism and are mainly expressed in liver, kidney and heart. Deficiency of these enzymes leads to two classical organic acidurias: methylmalonic and propionic aciduria. Patients with these diseases suffer from a whole spectrum of neurological manifestations that are limiting their quality of life. Current treatment does not seem to effectively prevent neurological deterioration and pathophysiological mechanisms are poorly understood. In this article we show evidence for the expression of the catabolic pathway of propionate metabolism in the developing and adult rat CNS. Both, MCM and PCC enzymes are co-expressed in neurons and found in all regions of the CNS. Disease-specific metabolites such as methylmalonate, propionyl-CoA and 2-methylcitrate could thus be formed autonomously in the CNS and contribute to the pathophysiological mechanisms of neurotoxicity. In rat embryos (E15.5 and E18.5), MCM and PCC show a much higher expression level in the entire CNS than in the liver, suggesting a different, but important function of this pathway during brain development.

A phase II trial of rituximab as adjuvant to intensive sequential chemotherapy in patients under 60 years with untreated poor-prognosis diffuse large B-cell lymphoma.

The potential benefit of rituximab as adjuvant to high-dose therapy (HDT) has been investigated in patients under 60 years with poor-risk (age-adjusted international prognostic index at 2-3) CD20+ diffuse large B-cell lymphoma (DLBCL). The treatment consisted of four cycles of high-dose CEOP (cyclophosphamide, epirubicin, vincristine, prednisone), plus etoposide and cisplatin during the two last cycles. Peripheral blood stem cells were collected after cycle 1, and reinfused after cycles 3 and 4. Four weekly rituximab infusions were subsequently delivered. Among the 36 patients included, 30 could complete chemotherapy schedule, and 24/36 received rituximab. A complete response occured in 26/36 patients (72%). With a median follow-up of 30 months, the estimated 5-year overall survival (OS) and event-free survival (EFS) rates (mean +/- s.d.) were 65 +/- 16 and 63 +/- 15%, respectively. For the 24 patients who received both chemotherapy and rituximab, the estimated 5-year OS and EFS rates were 86 +/- 14 and 82 +/- 15%. These data suggest that rituximab after HDT is feasible. Both complete remission rate and survival curves compare favorably with the poor outcome usually observed in high-risk DLBCL patients managed with HDT without rituximab.

Increased NO production in lysinuric protein intolerance.

Lysinuric protein intolerance (LPI) is a disorder of dibasic amino acid transport secondary to mutation of the SLC7A7 gene characterized by renal failure, pulmonary alveolar proteinosis, lupus-like autoimmune symptoms and usually increased plasma citrulline. In order to better understand the underlying mechanism, we studied the plasma and urinary nitrite/nitrate (NO2-/NO3-) concentrations in three LPI patients and the in vitro NO2- production in cultured fibroblasts. Our data show that NO3- levels are increased in the plasma of patients with LPI. Similarly, NO2- release in the medium of cultured fibroblasts was increased. On this basis, we hypothesize that some of the poorly understood clinical signs of LPI could be related to the activation of the NO-citrulline pathway.

A randomized prospective multicentre trial of cefpirome versus piperacillin-tazobactam in febrile neutropenia.

Fever is frequently the only clinical sign of infection in patients with chemo-induced neutropenia. In this setting, empirical administration of broad spectrum antibiotics must be rapid. The aim of this work was to compare, for the first time, cefpirome (CPO) and piperacillin-tazobactam (PT) in a large randomized trial. Two hundred-eight febrile neutropenic episodes (FNE) (> or = 38.5 degrees C and ANC < or = 0.5 giga/l) were treated by randomization, as first line therapy, using either CPO 2 g x 2/day (105 cases) or PT 4 g x 3/day (103 cases), alone (CPO: 15/PT: 15), or plus aminoglycoside (165 cases, CPO: 82/PT: 83) or quinolone (CPO: 2/PT: 2). There were 131 men and 77 women aged between 17 and 83 years (median: 49) who received chemotherapy (n = 160) or allogeneic (n = 10) or autologous (n = 38) stem cell transplantations. Underlying diseases were: acute leukemia (n = 131), lymphoma (n = 33), myeloma (n = 16), solid tumor (n = 8), myeloproliferative disorder (n = 9), chronic lymphoid leukemia (n = 5), aplastic anemia (n = 3), myelodysplasia (n = 3). Distribution of age, neutropenia duration (median: 17 days), underlying disease, and protocol therapy duration (median: 11 days) was comparable in both arms. A microbiologically documented infection (MDI) was evidenced in 57 cases (27%). Bacteria were isolated from blood cultures in 54 cases (Gram positive: 32 cases). Their in vitro susceptibility rates to CPO and PT were not different. Two days after antibiotics initiation, clinical (fever disappearance) and microbiological (culture negativation) success rates (SR) were 62% for CPO versus 61% for PT and 50% versus 55% respectively in case of MDI (p = 0.89). Two deaths and 77 failures were registered. At the end of protocol, SR (no antibiotic change/absence of superinfection) was 59% with CPO versus 50% with PT (p = 0.27) and 53% versus 40% respectively in the 151 cases with neutropenia > or = 10 days (p = 0.17). The occurrence of side effects was similar in both arms. In our hands, the efficacy of CPO and PT was comparable for treating FNE.

Outcome of adult patients with acute myeloid leukemia who failed to achieve complete remission after one course of induction chemotherapy: a report from the BGMT Study Group.

Between 50 and 75% of adult patients with de novo acute myeloid leukemia achieve complete remission (CR) but 25 to 40% of them require more than one course of induction chemotherapy to achieve CR. In order to investigate the impact of this situation on the overall outcome of patients we conducted a retrospective analysis of 130 patients, resistant to a single induction course from among three consecutive protocols, using the same induction regimen employed by the BGMT study group. This group of patients has a particularly poor prognosis with relapse and survival rates of 70% and 14% respectively at 5 years. For these patients, being in CR after two induction courses appears to be a major prognostic factor for outcome, since the 5-year Kaplan-Meier survival probability is significantly better (29%, range 17-46) than of those patients with resistant disease (5%, range 2-13). However, results are worse than when complete remission is obtained after a single course. Thus, post remission treatment should have a powerful anti-leukemic effect in preventing relapse. Allogeneic bone marrow transplantation is a preferential strategy in this setting but to be effective this should be performed as early as possible. Furthermore, these results indicate that allogeneic bone marrow transplantation from an alternative donor should be considered in the absence of HLA identical sibling.

[Spinal cord compression caused by extramedullary hematopoiesis foci in the course of thalassemia]. / Compression médullaire par des foyers d'hématopoïèse extra médullaire au cours de la thalassémie.

BACKGROUND: Extramedullary haematopoiesis is a physiological response to chronic anemia, observed frequently during homozygous thalassemia. It is usually asymptomatic but can be manifested by compression of adjacent organs, particularly the spinal cord. CASE REPORT: A 44-year-old woman diagnosed with thalassaemia intermedia, was admitted for difficulties to walk and sphincter disturbances. Neurologic examination suggested spinal cord compression, which is confirmed by dorso-lumbar resonance magnetic imaging. The histology obtained by laminectomy led to the diagnosis of extramedullary hematopoiesis related to thalassemia. A radiotherapy enabled with good outcome. DISCUSSION: Spinal cord compressions by extramedullary hematopoiesis during thalassemia are uncommon (75 cases in the literature) but can induce severe sequelae if the diagnostic is not rapidly obtained. Magnetic resonance imaging is the gold standard allowing precise diagnosis and spreading of extramedullary hematopoiesis. Radiotherapy and more recently hydroxyurea are the first line treatment. CONCLUSION: This observation recalls that extramedullary hematopoiesis is a differential diagnostic of spinal cord compression in patients with thalassemia. A screening of paravertebral localization of extramedullary hematopoiesis should be performed in high risk thalassemic patients.

[Maternal phenylketonuria]. / Phénylcétonurie maternelle.

The child of a phenylketonuric woman is exposed during pregnancy to a high risk of growth retardation and malformation. The frequency of these abnormalities is proportional to the maternal phenylalanine blood concentrations. If a strict low protein diet is followed before conception and throughout gestation the risks of abnormalities are not higher than in the normal population. The maternal blood phenylalanine levels must be maintained between 120 and 250 mumol/l and the tyrosine blood levels between 45 and 90 mumol/l. Weekly blood analyses are mandatory. Regular dietary controls are necessary to assure that the adequate energetic intake and the correct amounts of vitamins and minerals recommended for a pregnant woman are sustained. A case report is the opportunity to discuss certain practical aspects concerning the monitoring of the pregnancy of a phenylketonuric woman and to make general recommendations.

[Hyperaminoaciduria in children]. / Les hyperaminoaciduries chez l'enfant.

Hyperaminoaciduria is a major disorder to be considered in the event of growth and mental retardation, convulsion and other unexplained clinical symptoms. This review should enable the general practitioner to determine the conditions necessitating urinary and blood amino acid analyses in order to improve the treatment of children presenting rare pathologies, the prognosis of whom depends on the rapidity of the intervention. The diagnosis and treatment of hereditary and renal hyperaminoaciduria are discussed and a physiological and physiopathological synthesis of the tubular reabsorption of amino acids is presented. The different clinical entities associated with hyperaminoaciduria are then briefly described according to their origin (renal or prerenal).

Separation of free amino acids in human plasma by capillary electrophoresis with laser induced fluorescence: potential for emergency diagnosis of inborn errors of metabolism.

Free amino acids (AAs) in human plasma are derivatized with 3-(4-carboxybenzoyl)quinoline-2-carboxaldehyde (CBQCA) and analyzed by capillary electrophoresis (CE) with laser induced fluorescence (LIF) detection. The labeling procedure is significantly improved over results reported previously. Derivatization can be completed in 40 min, with concentrations as low as 4 x 10(-8) M successfully labeled in favourable cases. Twenty-nine AAs (including 2 internal standards) are identified and can be reproducibly separated in 70 min. Migration time RSD values for 23 of these AAs were calculated and found in the range from 0.5 to 4%. The rapid derivatization procedure and the resolution obtained in the separation are sufficient for a semi-quantitative, emergency diagnosis of several inborn errors of metabolism (IEM). Amino acid profiles for both normal donor plasma samples and plasma samples of patients suffering from phenylketonuria, tyrosinemia, maple syrup urinary disease, hyperornithinemia, and citrullinemia are studied.

Difference in the homocysteine-lowering effect of folic acid in haemodialysis patients with and without occlusive vascular disease.

BACKGROUND: Hyperhomocysteinaemia has been identified as an independent cardiovascular risk factor and is found in more than 85% of patients on maintenance haemodialysis. Previous studies have shown that folic acid can lower circulating homocysteine in dialysis patients. We evaluated prospectively the effect of increasing the folic acid dosage from 1 to 6 mg per dialysis on plasma total homocysteine levels of haemodialysis patients with and without a history of occlusive vascular artery disease (OVD). METHODS: Thirty-nine stable patients on high-flux dialysis were studied. Their mean age was 63 +/-11 years and 17 (43%) had a history of OVD, either coronary and/or cerebral and/or peripheral occlusive disease. For several years prior to the study, the patients had received an oral post-dialysis multivitamin supplement including 1 mg of folic acid per dialysis. After baseline determinations, the folic acid dose was increased from 1 to 6 mg/dialysis for 3 months. RESULTS: After 3 months, plasma homocysteine had decreased significantly by approximately 23% from 31.1 +/- 12.7 to 24.5 +/- 9 micromol/l (P = 0.0005), while folic acid concentrations had increased from 6.5 +/- 2.5 to 14.4+/-2.5 microg/l (P < 0.0001). However, the decrease of homocysteine was quite different in patients with and in those without OVD. In patients with OVD, homocysteine decreased only marginally by approximately 2.5% (from 29.0 +/- 10.3 to 28.3 +/- 8.4 micromol/l, P = 0.74), whereas in patients without OVD there was a significant reduction of approximately 34% (from 32.7+/-14.4 to 21.6+/-8.6 micromol/l, P = 0.0008). Plasma homocysteine levels were reduced by > 15% in three patients (18%) in the group with OVD compared with 19 (86%) in the group without OVD (P = 0.001), and by > 30% in none of the patients (0%) in the former group compared with 13 (59%) in the latter (P = 0.001). CONCLUSIONS: These results indicate that the homocysteine-lowering effect of folic acid administration appears to be less effective in haemodialysis patients having occlusive vascular disease than in those without evidence of such disease.

Water-soluble vitamin levels in patients undergoing high-flux hemodialysis and receiving long-term oral postdialysis vitamin supplementation.

The prescription of multivitamin supplements for dialysis patients is routine practice, but the doses prescribed differ greatly from one dialysis center to another. Few data are available concerning long-term vitamin supplementation and its effects on patients either on high-flux hemodialysis or receiving postdialysis supplementation. For several years, we have systematically prescribed to our patients an oral postdialysis multivitamin supplement containing thiamine hydrochloride 100 mg, riboflavin 20 mg, pyridoxine hydrochloride 50 mg, folic acid 6 mg, and ascorbic acid 500 mg. The aim of this study was to perform a cross-sectional long-term evaluation of the vitamin levels in patients who received this vitamin supplement for at least 12 months. We also were interested in investigating the plasma oxalic acid and total homocysteine levels associated with the long-term prescription of these vitamin supplements. Thirty-three patients on high-flux dialysis were studied. Vitamin levels and/or vitamin-dependent enzymatic activities were within the normal range (N) in all patients. The mean results (+/-SD) were plasma ascorbic acid 13.6 +/- 6.4 mg/L (N > 4), plasma folate 14.1 +/- 1.1 microg/L (N > 3), for vitamin B1, alpha-ETK 1.02 +/- 0.02 (N < 1.18) and ETKo 100 +/- 13 U/L (N > 70), for vitamin B2, alpha-EGR 1.00 +/- 0.07 (N < 1.52) and EGRo 1282 +/- 213 U/L (N > 672), and for vitamin B6, alpha-EGOT 1.34 +/- 0.10 (N < 1.8) and EGOTo 380 +/- 84 U/L (N > 228). Plasma oxalic acid was higher than normal in all patients (mean = 61 +/- 15 micromol/L, N < 33). However, all patients had oxalic acid levels within the range reported in the literature for patients not taking extra ascorbic acid. Mean total homocysteine was 24 +/- 8 micromol/L with only 4 patients (12%) having normal levels (N < 15). In conclusion, the postdialysis supplement given provides adequate vitamin levels in almost all patients in the long term. Postdialysis prescription allows an optimal compliance with the treatment, is well accepted by the patients, and is cost-effective.

Clinical chemistry variables in normal elderly and healthy ambulatory populations: comparison with reference values.

Laboratory values of the most commonly assayed clinical chemistry variables were determined in selected elderly and healthy ambulatory populations. The upper and lower limits (2.5 and 97.5 fractiles) were compared with the adult reference values in use in university hospitals of Switzerland. The results suggest that conventional adult reference values can be used for most variables in the elderly and that these values are also useful in an ambulatory population.

Urinary phosphate/creatinine, calcium/creatinine, and magnesium/creatinine ratios in a healthy pediatric population.

OBJECTIVE: To determine reference values for urinary phosphate/creatinine (Cr) concentration ratios and to complete reference values for urinary calcium/creatinine and magnesium/creatinine ratios in the second morning urine sample of healthy infants, children, and adolescents. DESIGN: Urinary P/Cr, Ca/Cr, and Mg/Cr ratios were determined from the second morning urine sample. Two urine samples were obtained 1 week apart from most subjects to assess reproducibility. SETTING: Kindergartens and schools of Lausanne, Switzerland. PARTICIPANTS: A total of 410 healthy children aged 1 month to 17 years (197 girls and 213 boys) participated in the study. RESULTS: The 5th and 95th percentiles were estimated from 664 urine samples. There were no differences related to sex. A nonlinear regression in terms of age was used to smooth the estimated percentiles yielding reference curves from which critical values may be obtained for any given age. The 95th percentile for urinary Ca/Cr and Mg/Cr agreed with previously reported values in children older than 7 years. The upper limit of the three solute/creatinine ratios decreased significantly with age: for urinary P/Cr from 19.0 mol/mol at 1 month to 2.7 at 14 years; for urinary Ca/Cr from 2.2 to 0.7 mol/mol, and for urinary Mg/Cr from 2.2 to 0.6 mol/mol. Lower limits varied little. Interindividual and intraindividual variations decreased with age. CONCLUSIONS: Urinary P/Cr, Ca/Cr, and Mg/Cr ratios vary strongly with age. We provide reference values, expressed both in SI and in mass units, for urinary P/Cr, Ca/Cr, and Mg/Cr in children aged one month to 17 years.

In vivo and in vitro effects of somatostatin and insulin on glucagon release in a human glucagonoma.

Inhibition of pancreatic glucagon secretion has been reported to be mediated by glucose, insulin and somatostatin. As no human pancreatic alpha-cell lines are available to study in vitro the relative importance of insulin and glucose in the control of pancreatic glucagon release, we investigated a patient presenting with a malignant glucagonoma who underwent surgical resection of the tumour. Functional somatostatin receptors were present as octreotide administration decreased basal glucagon and insulin secretion by 52 and 74%, respectively. The removed tumour was immunohistochemically positive for glucagon, chromogranin A and pancreatic polypeptide but negative for insulin, gastrin and somatostatin. The glucagonoma cells were also isolated and cultured in vitro. Incubation experiments revealed that change from high (10 mM) to low (1 mM) glucose concentration was unable to stimulate glucagon secretion. A dose-dependent inhibition of glucagon release by insulin was however, observed at low glucose concentration. These findings demonstrate that insulin could inhibit glucagon secretion in vitro in the absence of elevated glucose concentrations. These data suggest, as observed in vivo and in vitro in several animal studies, that glucopenia-induced glucagon secretion in humans is not mediated by a direct effect of low glucose on alpha-cells but possibly by a reduction of insulin-mediated alpha-cell suppression and/or an indirect neuronal stimulation of glucagon release.

Effect of L-lysine on nitric oxide overproduction in endotoxic shock.

1. An enhanced production of nitric oxide (NO) from L-arginine, related to the diffuse expression of an inducible NO synthase (iNOS), contributes to the pathogenesis of endotoxic shock. Since iNOS activity depends on extracellular L-arginine, we hypothesized that limiting cellular L-arginine uptake would reduce NO production in endotoxic shock. We investigated the effects of L-lysine, an inhibitor of L-arginine uptake through system y+, on NO production, multiple organ dysfunction and lactate levels, in normal and endotoxaemic rats. 2. Anaesthetized rats challenged with intravenous lipopolysaccharide (LPS, 10 mg kg[-1]) received a 5 h infusion of either L-lysine (500 micromol kg(-1) h(-1), n = 12) or isotonic saline (2 ml kg(-1) h(-1), n = 11). In rats treated with saline, LPS produced a large increase in plasma nitrate and L-citrulline concentrations at 5 h, both markers of enhanced NO production. LPS also caused severe hypotension, low cardiac output and marked hyperlactataemia. All these changes were significantly reduced by L-lysine administration. 3. Endotoxaemia also caused a significant rise in the plasma levels of alanine aminotransferase (ALAT), lipase, urea and creatinine, and hence, liver, pancreatic and renal dysfunction. These changes tended to be less pronounced in rats treated with L-lysine, although the differences did not reach statistical significance. 4. Similar experiments were conducted in 10 rats challenged with LPS vehicle in place of LPS and then treated with L-lysine (500 micromol kg(-1) h(-1), n = 5) or saline (2 ml kg(-1) h(-1), n = 5) for 5 h. In these animals, all the haemodynamic and metabolic variables remained stable and not statistically different between both treatment groups, except for a slight rise in ALAT, which was comparable in L-lysine and saline-treated rats. 5. In conclusion, L-lysine, an inhibitor of cellular L-arginine uptake, reduces NO production and exerts beneficial haemodynamic effects in endotoxaemic rats. L-lysine also reduces hyperlactataemia and tends to blunt the development of organ injury in these animals. Contrastingly, L-lysine has no effects in the absence of endotoxin and thus appears to act as a selective modulator of iNOS activity.

Visceral leishmaniasis and HIV-1 co-infection in southern France.

Between 1986 and 1993 visceral leishmaniasis (VL) was diagnosed in 50 adult patients with human immunodeficiency virus type 1 (HIV-1) infection (8 females, 42 males: 31 intravenous drug users, 11 homosexual or bisexual men, 6 heterosexual individuals, 2 blood recipients) from 5 hospital centres in southern France. Diagnosis of VL was by demonstration of Leishmania and isolation of promastigotes by culture in Novy-McNeal-Nicolle medium. Leishmania isolates were identified by their isoenzyme profile in 28 patients. All the patients were immunocompromised when VL was diagnosed. Their median CD4 cell count was 25 x 10(6) (0-200). However, only 21 patients (42%) fulfilled the 1987 CDC criteria for the acquired immune deficiency syndrome before VL developed. Fever (84%), splenomegaly (56%), hepatomegaly (34%), and pancytopenia (62%) were the most common presenting features. Clinical signs were lacking in 10% of patients. Anti-leishmanial antibodies were detected by indirect immunofluorescence or enzyme-linked immunosorbent assay in 26/47 cases (55%). Combining these techniques with Western blotting (WB) gave a positivity rate of 95%. Amastigotes were demonstrated in bone marrow aspirates in 47 cases (94%). Unusual sites for parasites were found in 17 patients (34%), mainly in the digestive tract but also skin and lung. Viscerotropic L. infantum zymodeme MON-1 was characterized in 86% of cases. Dermotropic zymodemes MON-24, MON-29, MON-33, and a previously undescribed zymodeme MON-183, were isolated from 4 patients. The response rate to pentavalent antimony was 50% and to amphotericin B 100%, but clinical relapses were noted in both groups. In endemic areas, VL should be considered as a possible opportunistic infection in HIV-infected patients.(ABSTRACT TRUNCATED AT 250 WORDS)