Response to creatine analogs in fibroblasts and patients with creatine transporter deficiency.

Creatine transporter (CRTR) deficiency is one of the most frequent causes of X-linked mental retardation. The lack of an effective treatment for this disease, in contrast to creatine (Cr) biosynthesis disorders that respond to Cr monohydrate (CM), led us to analyze the efficacy of a lipophilic molecule derived from Cr, creatine ethyl ester (CEE), in fibroblasts and patients with CRTR deficiency. CM and CEE uptake studies were performed in six controls and four fibroblast cell lines from patients. We found a significant increase in Cr uptake after 72 h of incubation with CEE (500 micromol/L) in patients and control fibroblasts compared to incubation with CM. Subsequently, we assayed the clinical effect of CEE administration in four patients with CRTR deficiency. After 1 year of treatment, a lack of significant improvement in neuropsychological assessment or changes in Cr level in brain (1)H MRS was observed, and CEE was discontinued. In conclusion, this 12-month trial with CEE did not increase the brain concentration of Cr. Our in vitro data lend support to the idea of a certain passive transport of CEE in both pathological and control cells, although more lipophilic molecules or other cell systems that mimic the BBB should be used for a better approach to the in vivo system.

Creatine transporter deficiency in two adult patients with static encephalopathy.

Creatine transporter deficiency is a recently identified X-linked inborn error of metabolism. The natural course of the disease is not well delineated since clinical data from adult patients have scarcely been reported. A progressive course of the disease has been noted in a few described cases. We report the first two Spanish adult patients with creatine transporter deficiency and compare their clinical phenotype and the evolution of the disease with those of other published cases. The two brothers were identified in a study of a cohort of 610 mentally handicapped male patients. The disease was detected by biochemical studies and confirmed by DNA studies. The most significant clinical features were mental retardation, epilepsy and autistic behaviour, and these symptoms did not worsen, in contrast to other reports. They did not present gastrointestinal problems or movement disorders. Creatine transporter deficiency could be an underdiagnosed metabolic disorder and should be considered in adult patients with mental retardation. Clinical presentation of this disorder showed marked differences among adult patients and the course of the disease was static in our cases. Detection of additional adult patients might allow better understanding of the phenotypic outcome at a later age.

Arginine supplementation in four patients with X-linked creatine transporter defect.

BACKGROUND: Treatment with oral creatine monohydrate has not shown efficacy in patients with creatine transporter deficiency (CRTR-D). Another therapeutic option proposed is L-arginine, the substrate for the enzyme L-arginine:glycine amidinotransferase (AGAT). We evaluate clinical characteristics and cerebral creatine replenishment after L-arginine therapy in four patients with CRTR-D. PATIENTS AND METHODS: Four boys with genetically confirmed diagnosis of CRTR-D (ages 9-16 years) were supplemented with L-arginine (0.4 g/kg per day) for a period of 9 months. Treatment efficacy was evaluated by clinical and neuropsychological assessment and determination of creatine signals by brain proton magnetic resonance spectroscopy ((1)H-MRS). RESULTS: Epileptic seizures remained well controlled with antiepileptic drugs in three cases, both before and after L-arginine supplementation. Vineland Adaptive Behaviour Scale did not show any change in communication, daily living skills, socialization or motor skills, and a lack of improvement in brain (1)H-MRS follow-up was observed. L-Arginine was discontinued at the end of the observation period. CONCLUSIONS: Nine months of L-arginine supplementation did not show effectiveness in the four patients affected with CRTR-D in this protocol.

Urinary zinc and its relationships with microalbuminuria in type I diabetics.

We investigated whether zincuria is associated with microalbuminuria in type I (insulin-dependent) diabetics (IDDM). In 169 IDDM, 215 overnight urine samples were collected for simultaneous assay of zinc and albumin. In 76 samples with excessive microalbuminuria (greater than 15 mg/L), zincuria was higher than in the 139 other samples (0.83 +/- 0.06 vs 0.58 +/- 0.03 mg/L p less than 0.001), though zincuria and microalbuminuria were not significantly correlated. An exercise provocation test was performed in 78 IDDM. Although microalbuminuria increased, zincuria did not change during the test. Another group of 83 IDDM underwent urinary zinc determination over a period of 1 h of recumbency. The 48 patients who had a zincuria higher than the mean + 2 SD of control values had higher microalbuminuria at rest (48 +/- 16 micrograms/min vs 12 +/- 2 p less than 0.01) and after exercise (111 +/- 33 vs 42 +/- 14 p less than 0.02) than the remaining 35 subjects. Both subgroups did not differ for zinc intake and zincemia. Thus, incipient nephropathy as detected by the measurement of microalbuminuria is associated with a highly significant increase in zinc excretion, which is not proportional to albumin leakage, nor is it amplified during exercise. Hyperzincuria is not explained by an increase in zinc intake and does not result in hypozincemia.

Serum zinc and somatic growth in children with growth retardation.

A possible role for zinc deficiency in some cases of growth retardation in southern France was investigated. Control values for zinc for 160 children (age = 12.5 +/- 2.4 yr) are 0.85 +/- 0.22 mg/L (mean +/- 2 SD). Twenty-five children with low serum zinc values (less than 0.63 mg/L) and 25 matched short children with normal serum zinc values (greater than 0.63 mg/L) were studied. Children in the two groups did not differ significantly in age, pubertal development, stature, and weight. For the 25 children whose serum values were low, we found significantly lower values for bone age delay, growth velocity in mm/month, as well as the ratio between calculated growth velocity and theoretical growth velocity for the bone age (so that zincemia was correlated to these parameters in the whole sample of 50 subjects). Nevertheless, no significant difference could be found between the two groups for serum somatomedin C, serum osteocalcin values, and GH responses to the GH stimulatory tests (exercise test, overnight sampling, insulin-induced hypoglycemia, arginine test). Therefore, low serum zinc is associated with a retardation in both somatic growth and pubertal maturation.

Effects of zamic as a means for zinc supplementation in growing children.

We investigated the effects of zinc supplementation in case of moderate growth retardation in which GH treatment could not be used. Zamic (ZA, an association containing arginine, L-methionine, and zinc; from Aguettant pharmaceuticals) was compared with arginine aspartate (AA) (5 g) in a crossover randomized trial (6 mo of each treatment at random order over 1 yr). We present preliminary results of 24 children who completed the study (3 girls, 21 boys, age 9-13 yr). Subjects had to be prepubertal, with no GH deficiency diagnosed. In 15 subjects growth velocity was lower than 5 mm/mo: In this case ZA improved growth velocity (rising from 3.105 +/- 0.229 to 5.4 +/- 0.69 mm/mo p < 0.01), whereas the effect of AA was not significant. The increase in growth velocity was higher with ZA (+2.44 +/- 0.657 mm/mo) than AA (+0.438 +/- 0.450 mm/mo) p < 0.05. These results suggest that ZA is more efficient than AA, consistent with the hypothesis that zinc needs are increased in those children in this period of life.

Serum zinc in highly trained adolescent gymnasts.

Serum zinc was measured in 20 adolescent gymnasts (9 boys, 11 girls, age 12-15 yr) explored for detecting possible adverse effects of intense training on pubertal maturation and growth. They had low serum zinc (0.599 +/- 0.026 mg/L) when compared to matched control sedentary children (n = 118 mean 0.81 +/- 0.014 p < 0.001). Girls had lower zinc than boys (0.557 +/- 0.023 vs 0.651 +/- 0.044 p < 0.001). Zinc was correlated to isometric adductor strength (r = 0.468 p < 0.05). Children with serum zinc < 0.6 mg/L had lower insulin-like growth factor binding protein 3 than others (2.326 +/- 0.264 vs 2.699 +/- 0.12 p < 0.01). Thus, zinc is lowered in trained adolescent gymnasts and even lower in females. This reduction could play some role in abnormalities of puberty, growth, or muscular performance.

Effects of oral zinc gluconate on glucose effectiveness and insulin sensitivity in humans.

Zinc improves both insulin secretion and insulin sensitivity, and exerts insulin-like effects. We investigated its acute effects on the parameters of glucose assimilation determined with the minimal model technique from frequent sampling intravenous glucose tolerance test (FSIVGTT) in seven healthy volunteers. FSIVGTTs (0.5 g/kg of glucose, followed by 2 U insulin i.v. injection at 19 min) were performed after the subjects had taken 20 mg zinc gluconate twice (the evening before and 30 min before the beginning of the test) or placebo pills (simple blind randomized protocol). Glucose assimilation was analyzed by calculating Kg (slope of the exponential decrease in glycemia), glucose effectiveness Sg (i.e., ability of glucose itself to increase its own disposal independent of insulin response), and SI (insulin sensitivity, i.e. the effect of increases in insulinemia on glucose disposal). The two latter parameters were calculated by fitting the experimental data with the two equations of Bergman's "minimal model." Zinc increased Kg (p < 0.05) and Sg (p < 0.05), whereas SI and insulin first-phase secretion did not significantly increase. This study suggests that zinc improves glucose assimilation, as evidenced by the increase in Kg, and that this improvement results mainly from an increase in glucose effectiveness (insulin-like effect), rather than an action on insulin response or insulin sensitivity.

In vitro influence of zinc and magnesium on the deformability of red blood cells artificially hardened by heating.

Trace elements have been shown to improve red blood cell (RBC) deformability: zinc in sickle cell disease and magnesium in an in vitro model of chemically rigidified erythrocytes. In this study, we investigated the effect and the influence of incubation time of zinc or magnesium on an in vitro model of rigidified RBCs by heating. Erythrocyte rigidity was determined by viscosimetry at high shear rate by a falling ball viscosimeter MT 90. In the first part of the study, six normal volunteers participated. Viscosimetry was performed on native blood before and after heating the sample for 10 min at 50 degrees C. Therefore, increasing concentrations of zinc gluconate (final concentration: 0.5-4 g/L) or isotonic NaCl as control medium were added to the sample. Heating induced a twofold increase in all indices of RBC rigidity (p < 0.05). At all these concentrations of zinc, a highly significant, dose-related fluidifying effect was observed (40-70%): this effect was immediately obtained and did not change over 60 min. Even at the highest concentration, recovery was not complete. In the second part of the study, we studied magnesium's effects on blood. In a first protocol, whole blood was rigidified by heating at 56 degrees C for 10 min, and the correcting effect of 5 min of incubation at 37 degrees C of RBCs in 150 mmol/L NaCl, MgSO4, magnesium acetate, and magnesium gluconate was investigated. In a second protocol, the same incubation with NaCl and magnesium salts was made on blood that had not been previously heated.(ABSTRACT TRUNCATED AT 250 WORDS)

[Rheology and occlusive arterial disease of the legs]. / Rhéologie et artériopathie oblitérante des membres inférieurs.

Peripheral occlusive arterial disease (P.O.A.D.) is one of the situations in which hemorheological abnormalities are usually described. However the clinical relevance of hemorheological measurements in angiologic practice remains to be defined. The aim of the study was to investigate whether hemorheological disturbances are associated with alterations in oxygen diffusion and prognosis of the arterial disease. Three groups of patients were included in this work. First, a study was realized on 160 nondiabetic P.O.A.D patients (suffering from intermittent claudication to critical limb ischemia) in order to evaluate the possible influence of hemorheological disturbances on oxygen diffusion in distal tissue. A control group of 30 subjects matched for age and sex was also studied. A second study was performed on 80 diabetic P.O.A.D. patients (stage III and IV of Leriche and Fontaine classification) to determinate if hemorheological parameters could be considered as prognostic factors in the P.O.A.D. course. Hemorheological parameters were determined on different devices: red blood cell (RBC) aggregation by Myrenne aggregometer, blood and plasma viscosities by MT 90 falling ball viscometer. Transcutaneous oxygen pressure was measured by Radiometer TCM2 oxygen monitor. Several rheological parameters of non diabetic patients suffering from P.O.A.D. were significantly higher than those of control group subjects : blood viscosity (p < 0.05), plasma viscosity (p < 0.001), erythrocyte rigidity index (p < 0.01) and fibrinogen level (p < 0.0001). In the nondiabetic patients TcPO2 was negatively correlated with RBC aggregation, erythrocyte rigidity index and hematocrit /viscosity ratio. The diabetic patients who needed major amputation (above or below knee) presented significantly increased hemorheological parameters (blood viscosity, RBC aggregation, RBC rigidity index, hematocrit/viscosity ratio, fibrinogen level) compared to diabetic who had not been major amputated (no amputation or only toes' amputation). Our finding suggests that hemorheological factors (1) may influence oxygen transfer to distal tissues by maldistribution of blood flow and (2) may have prognostic significance in chronic peripheral occlusive arterial disease.

[Hemorrheological parameters during normal labor and uterine contraction]. / Paramètres hémorhéologiques pendant l'accouchement normal et la contraction utérine.

Considering the modified fluidity of blood during numerous kind of stress, the authors studied blood rheology during delivery as an example of a particularly severe stress. The authors measured blood and plasma viscosity and erythrocyte aggregation in 77 pregnant at the following stages of delivery: below 4 cm dilatation; more than 4 cm dilatation; during fetus expulsion, during after birth delivery. Apparent blood viscosity and viscosity adjusted to 45% hematocrit rose to reach a peak during expulsion (p less than 0.01) then to become normal again during placenta delivery (p less than 0.01). Hematocrit and plasmatic viscosity showed no changes during labour and expulsion. In addition erythrocyte aggregation was lowering during expulsion and delivery (stage with physiological defibrination). Rising blood viscosity might be explained by a red blood cell rigidification measured by the increasing of "Tk" (p less than 0.01) and by a nonsignificant increase of the filterability index measured by hemorheometer. In conclusion, delivery is accompanied by a blood hyperviscosity essentially related to a transient red blood cell rigidification.

[Hemorrheological characteristics of fetal blood drawn in utero from the cord]. / Caractéristiques hémorhéologiques du sang foetal prélevé in utero par cordocentèse.

Extensive studies of hemorheology of cord blood (drawn just after delivery) have evidentiated a peculiar rheological pattern: less filterable red cells, reduced erythrocyte aggregation, lowered plasma viscosity. This pattern has been suggested to be important for maintaining a sufficient O2 supply to fetal tissues, by avoiding hyperviscosity despite increased RBC rigidity. However, cord blood at birth is not exactly fetal blood and we are not yet aware of studies of fetal blood drawn in utero several weeks before delivery. For this reason, we investigated the rheological properties of fetal blood during intrauterine cord venepunctures in 27 pregnant women (25-30 week's gestation) who were explored for detection of fetal genetic or infectious diseases. Fetuses have lower plasma viscosity (p less than 0.001), lower RBC flexibility (measured by filterability on the Hémorhéomètre) (p less than 0.01) and higher hematocrit/viscosity ratio (p less than 0.01) than their mothers. While no temporal modification during the studied period (20-40 wk) was detected for hematocrit and plasma viscosity, RBC filterability (rigidity) seems to exhibit a 'U shaped curve' with a nadir between 25 and 30 weeks. This pilot study supports the hypothesis that the previously reported rheological properties of cord blood at birth reflect to some extent those of intra-uterine fetal blood.

A prospective epidemiological study on the occurrence of antiphospholipid antibody: the Montpellier Antiphospholipid (MAP) Study.

The objective of this study was to determine the prevalence and clinical significance of elevated antiphospholipid antibodies (APA) in a large series of patients admitted to a department of Internal Medicine. At the end of entry phase, 1014 patients were tested (488 males-526 females, mean age: 66.7 years, range 18-97). Seventy-two (7.1%) patients were found APA positive at least once: 44 males and 28 females, mean age 69 years, range 23 to 94. Twenty fulfilled the criteria of Primary Antiphospholipid Antibody Syndrome: 10 patients were referred for deep vein thrombosis, 3 had history of deep vein thrombosis, 1 had both arterial thrombosis and a history of venous thrombosis; 2 had thrombocytopenia; 3 had stroke, 1 had a history of a stroke. One patient had SLE according to ARA classification. The most frequent associated disease was cancer: 14 patients, 9 had evolutive malignant disease, 5 were in clinical remission of neoplasia. Other clinical conditions included chronic and/or acute alcoholic intoxication (n = 8), severe atherosclerosis (n = 4), leg ulcer (n = 4). Insufficient data are available about the evolution, but 7 patients died in the year following diagnosis. Eight patients had fluctuations in APA detection: 2 initially APA positive became negative, 5 initially negative became positive and 1 patient was alternatively positive, negative and positive without steroid treatment. Thus, as expected, APA occur in a variety of clinical disorders. The association with cancer or alcoholic intoxication deserves further investigations.