Association between housing type and γ-GTP increase after the Great East Japan Earthquake.

BACKGROUND: It has been reported that alcohol consumption increases after natural disasters, with an impact on health. However, the impact of relocation upon drinking behavior has been unclear. The aim of this study was to clarify the association between housing type and the impact of alcohol consumption on health after the Great East Japan Earthquake (GEJE) of 2011. METHODS: We analyzed 569 residents living in devastated areas of Ishinomaki city, who had undergone assessment of their γ-GTP levels at health check-ups in both 2010 and 2013, and had given details of the type of housing they occupied in 2013. The housing types were categorized into five groups: "same housing as that before the GEJE", "prefabricated temporary housing", "privately rented temporary housing/rental housing", "homes of relatives", and "reconstructed housing". We used fixed-effect regression analysis to examine the association between housing type after the GEJE and changes in γ-GTP after adjustment for age, BMI, housing damage, number of people in household, smoking status, presence of illness, psychological distress, and social network. RESULTS: The mean age of the participants was 71.5 years and 46.2% of them were men. The proportion of individuals who drank heavily, and suffered from psychological distress and insomnia, was highest among those living in privately rented temporary housing/rental housing. Compared with individuals who continued to occupy the same housing as those before the GEJE, the effect of change in γ-GTP was significantly higher in individuals who had moved to privately rented temporary housing/rental housing (b = 9.5, SE = 4.4, p < 0.05). CONCLUSION: Our present findings reveal that disaster victims who have moved to privately rented temporary housing/rental housing are at highest risk of negative health effects due to alcohol drinking.

Effects of ribavirin/sofosbuvir treatment and ITPA phenotype on endogenous purines.

Ribavirin (RBV), a purine analog, causes hemolytic anemia in some patients. In vitro, anemia appears to result from depletion of endogenous purines, but there are limited data in vivo. Single nucleotide polymorphisms in the gene encoding the inosine triphosphatase (ITPA) enzyme have been associated with protection against RBV-induced anemia and may mediate the effect of RBV treatment on endogenous purines. The purpose of this work was to determine the effect of RBV treatment on endogenous purine concentrations in individuals being treated for chronic hepatitis C virus (HCV) infection. Adenosine triphosphate (ATP), guanosine triphosphate (GTP), inosine triphosphate (ITP) and ribavirin triphosphate (RTP) were measured in whole blood obtained from 47 HCV-infected individuals at day zero (baseline), day three, day 28 and day 84 of RBV/sofosbuvir (SOF) treatment. ATP decreased -35.1% and -38.6% (p < 0.0001) at day 28 and day 84 of treatment, respectively compared to baseline. The decrease in ATP was greater in patients with ≤60% ITPA activity compared to those with 100% ITPA activity (-29.4% vs. -9.6%). GTP did not change during treatment but was 16.5% (p = 0.01) higher per 100 pmol/106 cells RTP in those with 100% ITPA activity. No significant change or effect of RTP or ITPA phenotype was noted for ITP. In summary, only ATP was reduced by RBV/SOF treatment and ITPA variants had larger reductions in ATP suggesting RBV-induced anemia is due to a different mechanism than predicted from in-vitro studies. These data emphasize the importance of characterizing the effect of nucleos(t)ide analog treatment on endogenous purines in-vivo.

The hemoglobin system of the serpent eel Ophisurus serpens: structural and functional characterization.

The hemoglobin system of the serpent eel Ophisurus serpens was structurally and functionally characterized with the aim of comparing it to the hemoglobin system of other fish species, as oxygen loading under the severe habitat conditions experienced by O. serpens could have necessitated specific adaptation mechanisms during evolution. The hemoglobin system of O. serpens includes one cathodic and four anodic components. The molecular mass of the α and ß chains of the cathodic component as well as the 2 α and 4 ß of the anodic components were determined. Analysis of the intact α and ß chains from cathodic hemoglobin and their proteolytic digestion products by high-resolution MS and MS/MS experiments resulted in 92 and 95 % sequence coverage of the α and ß globins, respectively. The oxygen binding properties of both hemoglobin components were analyzed with respect to their interactions with their physiological effectors. Stripped cathodic hemoglobin displayed the highest oxygen affinity among Anguilliformes with no significant effect of pH on O2-affinity. In the presence of both chloride and organic phosphates, O2-affinity was strongly reduced, and cooperativity was enhanced; moreover, cathodic hemoglobin contains two indistinguishable GTP-binding sites. Stripped anodic hemoglobins exhibited both low O2-affinity and low cooperativity and a larger Bohr effect than cathodic hemoglobin. The cathodic hemoglobin of O. serpens and the corresponding component of Conger conger share the greatest structural and functional similarity among hemoglobin systems of Anguilliformes studied to date, consistent with their phylogenetic relationship.

Effect of acute exercise on cardiovascular hemodynamic and red blood cell concentrations of purine nucleotides in hypertensive compared with normotensives rats.

OBJECTIVE: The mechanisms of exercise-induced health benefits are complex and not fully understood. This study investigated the effects of exercise and hypertension on cardiovascular hemodynamic responses and red blood cell (RBC) concentrations of purine nucleotides using normotensive and hypertensive rat models in vivo. METHODS: Sprague Dawley rats (SDRs) and spontaneously hypertensive rats (SHRs) were exercised on a treadmill for 15 min at a speed of 10 m/min and 5% grade. Blood samples were obtained from each rat before, during, and after exercise for measurement of adenosine 5'-triphosphate (ATP) and guanosine 5'-triphosphate (GTP) concentrations in RBCs by a validated high-performance liquid chromatography assay. They were returned to a restrainer after exercise, and hemodynamic recording collected continuously up to 6 h. Two separate groups (SDRs and SHRs) without exercise were used as controls. Biomarker data were compared between SDRs and SHRs using analysis of variance and t test and difference considered significant at p < 0.05. RESULTS: The study has demonstrated for the first time a difference in the postexercise effect between SDRs and SHRs. The 15 min of exercise significantly increased systolic blood pressure (SBP) (129 ± 16 to 162 ± 26 mmHg) and heart rate (HR) (416 ± 29 to 491 ± 26 bpm) in SDRs (p < 0.05), but not in SHRs. The postexercise hemodynamic effects were more profound in SHRs. SBP and diastolic blood pressure (DBP) also fell significantly in the control group of SHRs (SBP 184 ± 14 to 152 ± 29 mmHg and DBP 149 ± 9 to 120 ± 14 mmHg, p < 0.05 for both) towards the end of the experiment but not in the SDR group. The RBC concentrations of ATP and GTP increased after exercise in both SDRs and SHRs which were significantly correlated with the postexercise hemodynamic effect (p < 0.05). CONCLUSION: SHRs were more tolerant to increases in HR and SBP induced by exercise, and have more profound postexercise hemodynamic effects than SDRs. The hemodynamic effects were linked closely with RBC concentrations of ATP and GTP in both SDRs and SHRs.

[Clinical study of levofloxacin 500 mg qd in the treatment of cervicitis and intrauterine infections caused by Chlamydia trachomatis].

The clinical efficacy and safety of levofloxacin (LVFX) 500mg qd were evaluated in female patients with cervicitis with Chlamydia trachomatis and intrauterine infections. LVFX was administered orally at 500 mg qd for 7 days. Bacteriological efficacy was 94.4% (17/18) and clinical efficacy was 100% (16/16) at 14 to 21 days after the end of treatment in cervicitis. On the other hand, bacteriological efficacy and clinical efficacy at the end of treatment in intrauterine infections were 68.8% (11/16) and 94.7% (18/19), respectively. For safety, adverse drug reactions occurred in 9 of 43 patients (20.9%), i.e., increased y-GTP in 2 patients, glucose urine present in 2, and each of all other adverse reactions occurred in 1. All adverse drug reactions observed were either mild or moderate. Results suggested that LVFX 500 mg qd was effective and safe in the treatment of cervicitis with Chlamydia trachomatis and intrauterine infections.

Determination of 6-thioguanosine diphosphate and triphosphate and nucleoside diphosphate kinase activity in erythrocytes: novel targets for thiopurine therapy?

6-Thioguanine nucleotides are the sum of 6-thioguanosine 5'-monophosphate (TGMP), -diphosphate (TGDP), and -triphosphate (TGTP) representing essential metabolites involved in drug action of thiopurines. Elevated levels of TGDP have been associated with poor response to azathioprine therapy in patients with inflammatory bowel disease. The conversion of TGDP to TGTP is supposed to be catalyzed by nucleoside diphosphate kinase (NDPK). The aim of this work was to investigate simultaneously individual 6-thioguanosine phosphate levels and NDPK activity in red blood cells (RBCs) of patients on azathioprine therapy. Ion-pair high-performance liquid chromatography methods with fluorescence and ultraviolet detection were applied to quantify individual levels of 6-thioguanosine 5'-phosphates and NDPK activity, respectively, in RBCs. Recombinantly expressed NDPK isoforms A and B were unequivocally identified to catalyze the formation of TGTP (30.6 +/- 3.88 nmol x min x mg for NDPK A versus 41.2 +/- 1.05 nmol x min x mg for NDPK B). Comprehensive analyses on the stability of TGMP, TGDP, and TGTP and the reproducibility of NDPK activity in RBCs were performed to provide a reliable sampling protocol for clinical practice. Of note, isolation of RBCs within 6 hours followed by immediate storage at -80 degrees C is crucial for prevention of degradation of 5'-phosphates. In a clinical study of 37 patients on azathioprine, TGTP was the predominant 6-thioguanosine phosphate in RBCs. In contrast, three patients showed TGTP/(TGDP + TGTP) ratios of 57.2%, 64.3%, and 66% corresponding to elevated TGDP levels. NDPK activity ranged from 4.1 to 11.3 nmol x min x mg hemoglobin. No correlation between NDPK activity and the 6-thioguanosine phosphate levels was found. The question whether interindividual variability of NDPK activity may explain differences in 6-thioguanosine 5'-phosphates levels has to be investigated in a prospective large-scale study.

Characterization of the hemoglobins of the Australian lungfish Neoceratodus forsteri (Krefft).

We examined for the first time the hemoglobin components of the blood of the Australian lungfish, Neoceratodus forsteri and their functional responses to pH and the allosteric modulators adenosine triphosphate (ATP), guanosine triphosphate (GTP), 2,3-bisphosphoglyceric acid (BPG) and inositol hexaphosphate (IHP) at 25 degrees C. Lysates prepared from stripped, unfractionated hemolysate produced sigmoidal oxygen equilibrium curves with high oxygen affinity (oxygen partial pressure required for 50% hemoglobin saturation, p(50)=5.3 mmHg) and a Hill coefficient of 1.9 at pH 7.5. p(50) was 8.3 and 4.5 mmHg at pH 6 and 8, respectively, which corresponded to a modest Bohr coefficient (Delta log p(50)/Delta pH) of -0.13. GTP increased the pH sensitivity of oxygen binding more than ATP, such that the Bohr coefficient was -0.77 in the presence of 2 mmol L(-1) GTP. GTP was the most potent regulator of hemoglobin affinity, with concentrations of 5 mmol L(-1) causing an increase in p(50) from 5 to 19 mm Hg at pH 7.5, while the order of potency of the other phosphates was IHP>ATP>BPG. Three hemoglobin isoforms were present and each contained both alpha and beta chains with distinct molecular weights. Oxygen affinity and pH-dependence of isoforms I and II were essentially identical, while isoform III had a lower affinity and increased pH-dependence. The functional properties of the hemoglobin system of Neoceratodus appeared consistent with an active aquatic breather adapted for periodic hypoxic episodes.

Neurological aspects of hyperinsulinism-hyperammonaemia syndrome.

Hyperinsulinism-hyperammonaemia syndrome (HHS) is a rare cause of congenital hyperinsulinism, due to missense mutations in the GLUD1 gene, resulting in glutamate dehydrogenase (GDH) overactivity. The aim of this study was to document the spectrum of neurological disturbances associated with HHS and to identify possible phenotype-genotype correlations. We retrospectively analyzed the neurological outcomes of 22 consecutive patients (12 males, 10 females) aged from 18 months to 40 years and diagnosed with HHS. We analyzed demographic and clinical features and neuroradiological, biochemical, and genetic findings. Fourteen patients had childhood-onset epilepsy. Learning disability was found in 17 patients. Two patients had pyramidal involvement and one had generalized dystonia. Seizures were observed in 11 of 19 patients with documented GLUD1 mutations, and nine of these 11 patients had a mutation in the guanosine triphosphate (GTP) binding site. Our data demonstrate that neurological disorders in HHS are more frequent than previously thought and might suggest that mutations in the GTP binding site of GDH could be associated with more frequent epilepsy.

HPLC assay with UV detection for determination of RBC purine nucleotide concentrations and application for biomarker study in vivo.

ATP and other purine nucleotides are important biomarkers for ischemia and may have considerable potential as targets for management of ischemic heart disease and stroke. The main objective of the study is to develop a rapid HPLC assay, which has adequate sensitivity and specificity for measuring concentrations of ATP, ADP, AMP, GTP, GDP and GMP in erythrocytes (RBC). The assays used ion-pair chromatography coupled with ultraviolet detection at 254 nm to separate and detect the purine nucleotides. Using 50-100 microL of RBC lysate as blank biologic matrix, the assay was linear from 100 to 2000 microg/mL for ATP and ADP, and 20-400 microg/mL for AMP, GTP, and GDP with coefficients of determination (r(2)) >0.99. GDP and GMP were not measurable in the study because of low concentrations and interference from endogenous materials, respectively. The intra-assay and inter-assay variations over a period of 1 year were less than 10% and 20%, respectively for most of the nucleotides. The assay was successfully applied to two pilot biomarker studies to measure RBC concentrations of the purine nucleotides in rats under restraining and exercise conditions. Preliminary results showed that the RBC concentrations of ATP and GTP were higher in the spontaneously hypertensive rats (SHR) compared to the Sprague-Dawley (SD) rats, and that exercise increased RBC concentrations of ATP in rats treated with the calcium channel blocker diltiazem.

Multiple strategies of Lake Victoria cichlids to cope with lifelong hypoxia include hemoglobin switching.

Many fish species adapt to hypoxia by reducing their metabolic rate and increasing hemoglobin-oxygen (Hb-O(2)) affinity. Pilot studies with young broods of cichlids showed that the young could survive severe hypoxia in contrast with the adults. It was therefore hypothesized that early exposure results in improved oxygen transport. This hypothesis was tested using split brood experiments. Broods of Astatoreochromis alluaudi, Haplochromis ishmaeli, and a tilapia hybrid (Oreochromis) were raised either under normoxia (NR; 80-90% air saturation) or hypoxia (HR; 10% air saturation). The activity of the mitochondrial citrate synthase was not different between NR and HR tilapia, but was significantly decreased in HR A. alluaudi and H. ishmaeli, indicating lowered maximum aerobic capacities. On the other hand, hemoglobin and hematocrit levels were significantly higher in all HR fish of the three species, reflecting a physiological adaptation to safeguard oxygen transport capacity. In HR tilapia, intraerythrocytic GTP levels were decreased, suggesting an adaptive increase of blood-O(2) affinity. Similar changes were not found in HR H. ishmaeli. In this species, however, all HR specimens exhibited a distinctly different iso-Hb pattern compared with their NR siblings, which correlated with a higher intrinsic Hb-O(2) affinity in the former. All HR cichlids thus reveal left-shifted Hb-O(2) equilibrium curves, mediated by either decreased allosteric interaction or, in H. ishmaeli, by the production of new hemoglobins. It is concluded that the adaptation to lifelong hypoxia is mainly due to improved oxygen transport.

Simultaneous determination of guanosine and guanosine-5'-triphosphate in biological sample using gold nanoparticles modified indium tin oxide electrode.

A nanogold modified indium tin oxide (ITO) electrode was used for the simultaneous determination of guanosine and GTP at pH 7.2. The electrode exhibited an effective catalytic response towards their oxidation and lowered the oxidation potential of guanosine by approximately 120 mV and GTP by approximately 183 mV. Linear concentration curves were obtained for guanosine with a detection limit of 9.8 x 10(-8) M and 5.5 x 10(-8) M for GTP. The concentration of guanosine and GTP were also estimated in the human blood plasma samples using gold nanoparticles modified ITO electrode with good reproducibility.

Obesity is the only independent factor associated with ultrasound-diagnosed non-alcoholic fatty liver disease: a cross-sectional case-control study.

OBJECTIVE: There is increasing interest in ultrasound-diagnosed non-alcoholic fatty liver disease (NAFLD) in the ambulatory care setting. The aim of this study was to determine the clinical and metabolic features of ultrasound-diagnosed NAFLD. MATERIAL AND METHODS: Fifty ultrasound-diagnosed NAFLD patients who had not consumed alcohol for at least the previous 3 months were matched with 100 controls by age and gender distribution. Clinical, biochemical, and nutritional variables were compared between the ultrasound-diagnosed NAFLD patients and the controls. Conditional logistic regression analyses were used to identify independent factors associated with ultrasound-diagnosed NAFLD. RESULTS: The ultrasound-diagnosed NAFLD patients had higher values on the anthropometric measurements than those of the controls. Aspartate aminotransferase (ASAT), alanine aminotransferase (ALAT), uric acid, and gamma-glutamyl transpeptidase levels were higher in the ultrasound-diagnosed NAFLD patients than those in the controls (p<0.001). The ASAT/ALAT ratio of the ultrasound-diagnosed NAFLD patients was lower than that of the controls (p<0.001). Total cholesterol, triglycerides, high-density lipoprotein (HDL)-cholesterol, non-HDL-cholesterol, atherogenic index, fasting glucose, systolic blood pressure (BP), diastolic BP, and pulse pressure were higher in the ultrasound-diagnosed NAFLD patients than in the control subjects, while lipoprotein(a) was lower. There were no significant differences in low-density lipoprotein (LDL)-cholesterol levels or nutritional intake between patients and controls. Abnormal ASAT or ALAT, hypertriglyceridemia, lower HDL-cholesterol levels, silent myocardial ischemic pattern on electrocardiogram (ECG), impaired fasting glucose, and obesity were common among the ultrasound-diagnosed NAFLD patients. The only independent factor associated with ultrasound-diagnosed NAFLD was obesity (p<0.001). CONCLUSIONS: Our data suggest that NAFLD diagnosed by ultrasound is associated with hypertriglyceridemia, impaired fasting glucose, silent myocardial ischemic pattern of ECG, obesity, and abnormal liver tests in adults. Among these factors, obesity was the only independent factor associated with ultrasound-diagnosed NAFLD.

[Assessment of goserelin treatment in adjuvant therapy for premenopausal patients with breast cancer in Japan-zoladex breast cancer study group trial-B].

OBJECTIVE: Goserelin (GOS) therapy in an adjuvant setting for estrogen receptor(ER)-positive premenopausal patients with breast cancer was assessed in a randomised comparative study. METHODS: ER positive premenopausal patients with n + or n 0 and T > or = 3 cm received tamoxifen (TAM) 20 mg/day, GOS 3.6 mg/4 weeks or GOS + TAM for 2 years, and the clinical efficacy and safety of these regimens were assessed. RESULTS: In the data analysis of total 207 patients, hazard ratios of disease free survival (DFS) and overall survival (OS) in the GOS group compared to the TAM group were 0.87 and 2.10,respectively. The incidence of adverse drug reactions was similar (42-55%) in all three groups. Since the number of patients in this study did not reach the target number, the efficacy could not be assessed from a statistical aspect. Therefore,meta-analysis with similar foreign studies(ZIPP) was implemented. The results of meta-analysis showed that the hazard ratios of DFS and OS in the GOS group compared to the non-GOS group were 0.83 and 0.85, respectively. CONCLUSION: Although the analysis of 207 patients did not show any statistically significant difference between each of the treatment groups, the results of meta-analysis showed a significant prolongation of DFS in the GOS group. Also high tolerability of GOS was suggested. From these results, GOS was considered highly useful in adjuvant therapy for ER-positive premenopausal patients with breast cancer.

Thiopurine therapies: problems, complexities, and progress with monitoring thioguanine nucleotides.

Metabolism of thiopurine drugs--azathioprine, 6-mercaptopurine, and 6-thioguanine--has provided a powerful pharmacogenetic model incorporating polymorphism of the enzyme thiopurine methyltransferase (TPMT) and the primary active metabolite, thioguanine nucleotide (TGN). However, a sense of uncertainty about the usefulness of TGNs and other thiopurine metabolites has appeared. This review critically appraises the basis of thiopurine metabolism and reveals the problems and complexities in TGN research. Erythrocyte TGN is used in transplantation medicine and in chronic inflammatory conditions such as Crohn's disease, as a "surrogate" pharmacokinetic parameter for TGN in the target cells: leukocytes or bone marrow. It is not generally appreciated that erythrocytes do not express the enzyme IMP dehydrogenase and cannot convert mercaptopurine to TGN, which explains some of the confusion in interpretation of erythrocyte TGN measurements. TGN routinely measured in erythrocytes derives from hepatic metabolism. Another concern is that TGN are not generally assayed directly: most methods assay the thiopurine bases. Ion-exchange HPLC and enzymatic conversion of TGNs to nucleosides have been used to overcome this, and may reveal undisclosed roles for an unusual cytotoxic nucleotide, thio-inosine triphosphate, and methylated thiopurines. There appear to be additional interactions between xanthine oxidase and TPMT, and folate and TPMT, that could predict leukopenia. Difficult questions remain to be answered, which may be assisted by technological advances. Prospective TGN studies, long overdue, are at last revealing clearer results.

Efficacy and effectiveness of liver screening program to detect fatty liver in the periodic health check-ups.

To determine whether the current liver screening program for fatty liver has sufficient scientific evidence to justify its continued implementation. The liver screening program to detect fatty liver was performed on 411 Japanese workers utilizing serum aspartate aminotransferase (ALT), alanine aminotransferase (AST), and gammaglutamyl transpeptidase (gamma-GTP). Based on the preceding studies, subjects with viral and alcohol hepatitis were excluded from the evaluation. The diagnosis of fatty liver was based on ultrasound findings. The program was evaluated by efficacy and effectiveness; efficacy was measured according to the receiver operating characteristic (ROC) curves in comparison with the Body Mass Index (BMI). Effectiveness, based on the efficacy determinations, was assessed by means of the positive predictive value (PPV) test performance, the disease characteristics, and the program price. The diagnostic performances of ALT and BMI were nearly acceptable but far from excellent. The areas under the curves of the two indices were 0.69 and 0.63, respectively and these were statistically equivalent. The PPV ranged from 15 to 28% where the prevalence of fatty liver was 12.3%. The price of the program was estimated at US 4 dollars per person based on the medical reimbursement fee rate. The efficacy of the liver screening program was found to be insufficient and BMI monitoring may provide a more suitable and inexpensive alternative. Furthermore, the effectiveness of the program is open to question, considering the generally benign prognosis of the disease in the absence of any accompanying morbid conditions and the high price of the program.

Mycophenolate mofetil treatment following renal transplantation decreases GTP concentrations in mononuclear leucocytes.

MMF (mycophenolate mofetil) has been proven to provide an effective immunosuppression by non-competitive selective reversible inhibition of IMPDH (inosine monophosphate dehydrogenase), the enzyme playing a crucial role in GTP biosynthesis. However, the exact metabolic changes induced by inhibition of IMPDH in target cells of the immune system have been the subject of recent debate. The aim of the present study was to evaluate whether MMF treatment produced sustained changes in the guanosine nucleotide pool of MNLs (mononuclear leucocytes) in vivo. Sixty-two renal failure patients were divided into three groups: chronic renal failure patients undergoing haemodialysis (CRF-HD; n=20) and two groups of patients after renal transplantation, the first on AZA (azathioprine; TN-AZA; n=23) and the second treated with MMF (TN-MMF; n=19). In addition, MNLs from 25 healthy subjects were analysed as controls. Anion-exchange HPLC was used to quantify purine and pyrimidine nucleotides in MNLs. We report a significant decrease in GTP and the total MNL guanine nucleotide pool in the TN-MMF group (P<0.05) compared with control, CRF-HD and TN-AZA groups, although no significant differences were found between any of the other groups. Adenine nucleotide concentrations in MNLs were decreased in the TN-AZA group, but not in the TN-MMF group compared with the CRF-HD group and controls. There were no differences in CTP concentrations, but UTP concentrations were decreased in the CRF-HD, TN-AZA and TN-MMF groups compared with controls. MMF caused a significant and sustained decrease in the guanine nucleotide pool in MNLs from renal transplant recipients. This decrease contrasts with the elevation in GTP reported in erythrocytes of MMF-treated patients.

Mycophenolate mofetil, an inhibitor of inosine monophosphate dehydrogenase, causes a paradoxical elevation of GTP in erythrocytes of renal transplant patients.

The immunosuppressant MMF (mycophenolate mofetil) has increasingly replaced AZA (azathioprine) in renal transplantation. MMF is a prodrug of MPA (mycophenolic acid), which inhibits lymphocyte IMPDH (inosine monophosphate dehydrogenase), thereby drastically decreasing GTP concentrations essential to lymphocyte proliferation in vitro and in vivo. Erythrocyte GTP concentrations are commonly elevated in severe renal disease, but normalize following successful engraftment. Consequently, elevated GTP in renal transplant recipients might signal impending loss of immunosuppression and graft failure. In the present study, we compared erythrocyte nucleotides and plasma metabolites in two groups of 25 patients after renal transplantation, both receiving prednisolone and cyclosporin A, but one group receiving MMF and the other AZA. No patients had recent allograft biopsy evidence of rejection. Erythrocyte GTP concentrations at MMF commencement were 50.4+/-23.4 micromol/l. An increase occurred during the first 3 months after transplant when MMF was used de novo, stabilizing at 146.7+/-62.9 micromol/l after 4 months. This was significantly higher (P=2.5 x 10(-6)) than erythrocyte GTP (40.4+/-15.9 micromol/l) in the AZA group, which was essentially unchanged from values immediately after successful transplantation. The effect of MMF on erythrocyte GTP levels was reversible, since GTP levels fell when MMF therapy was terminated. The results demonstrate paradoxically high GTP concentrations in erythrocytes of renal transplant patients receiving MMF. MPA may stabilize reticulocyte IMPDH, allowing the protein to persist during erythropoiesis. This behaviour is in marked contrast with the decrease in GTP levels seen in white blood cells of patients on chronic MMF therapy.

A severe variant of childhood ataxia with central hypomyelination/vanishing white matter leukoencephalopathy related to EIF21B5 mutation.

Childhood ataxia with central hypomyelination (CACH)/vanishing white matter (VWM) leukoencephalopathy is related to mutations in all five genes of the eukaryotic translation initiation factor (eIF2B). In a fatal infantile leukoencephalopathy, which the authors previously classified as a severe variant of CACH/VWM, a new homozygous missense mutation in the EIF2B5 gene was found. Abnormal decrease in blood uric acid and increase of erythrocyte guanosine 5'-diphosphate sugars found in two siblings may contribute to the explanation of this particularly severe condition.

The aerobic physiology of the air-breathing blue gourami, Trichogaster trichopterus, necessitates behavioural regulation of breath-hold limits during hypoxic stress and predatory challenge.

Physiological characteristics of the blood oxygen transport system and muscle metabolism indicate a high dependence on aerobic pathways in the blue gourami, Trichogaster trichopterus. Haemoglobin concentration and haematocrit were modest and the blood oxygen affinity (P50=2.31 kPa at pH 7.4 and 28 degrees C) and its sensitivity to pH (Bohr factor, phi=-0.34) favour oxygen unloading at a relatively high oxygen pressure (PO2). The intracellular buffering capacity (44.0 slykes) and lactate dehydrogenase (LDH) activity (154.3 iu g(-1)) do not support exceptional anaerobic capabilities. Air-breathing frequency in the blue gourami is expected to increase when aquatic oxygen tensions decline. Under threat of predation, however, this behaviour must be modified at a potential cost to aerobic metabolism. We therefore tested the hypothesis that metabolic responses to predatory challenge and aquatic hypoxia are subject to behavioural modulation. Computer-generated visual stimuli consistently reduced air-breathing frequency at 19.95, 6.65 and 3.33 kPa PO2. Bi-directional rates of spontaneous activity were similarly reduced. The metabolic cost of this behaviour was estimated and positively correlated with PO2 but not with visual stimulation thus indicating down-regulation of spontaneous activity rather than breath-holding behaviour. Neither PO2 nor visual stimulation resulted in significant change to muscle lactate and ATP concentrations and confirm that aerobic breath-hold limits were maintained following behavioural modulation of metabolic demands.

Effect of mycophenolate mofetil therapy on inosine monophosphate dehydrogenase induction in red blood cells of heart transplant recipients.

BACKGROUND: Mycophenolic acid is reported to provide effective immunosuppression by inhibiting inosine monophosphate dehydrogenase. In an attempt to monitor the biological effects of long-term therapy with mycophenolate mofetil, we measured levels of guanosine 5' triphosphate and adenosine 5' triphosphate in red blood cells (RBCs) of patients after heart transplantations. METHODS: Fifty-two patients enrolled in the study were randomly assigned to one of two groups. Patients in the control group (n = 27) received cyclosporine A (INN, ciclosporin), azathioprine, and prednisone. Patients in the study group (n = 25) were switched from azathioprine to mycophenolate mofetil 3 months after the heart transplantation. Adenosine 5' triphosphate and guanosine 5' triphosphate levels were determined by means of HPLC. The activities of inosine monophosphate dehydrogenase and hypoxanthine-guanine phosphoribosyltransferase, which are responsible for guanine nucleotide formation, were measured in RBCs by radiochemical methods. RESULTS: Adenosine 5' triphosphate levels were unchanged in patients treated with mycophenolate mofetil, whereas those of the control group who received azathioprine (from 142 +/- 26 pmol/10(6) RBCs to 165 +/- 25 pmol/10(6) RBCs; P <.001) increased. As the length of mycophenolate mofetil therapy increased, patients in the study group showed significantly elevated guanosine 5' triphosphate levels (15.6 +/- 6.1 pmol/10(6) RBCs versus 6.6 +/- 2.1 pmol/10(6) RBCs; P <.001) and a 5-fold increase in inosine monophosphate dehydrogenase activity (108.6 +/- 13.3 pmol/mg of protein per hour versus 22.5 +/- 1.7 pmol/mg of protein per hour; P <.001) compared with the control group. In addition, a slight but significant enhancement of hypoxanthine-guanine phosphoribosyltransferase activity was seen in the mycophenolate mofetil group. CONCLUSIONS: Our studies have shown that long-term administration of mycophenolate mofetil is associated with increasing guanosine 5' triphosphate levels in RBCs as the result of an induction of inosine monophosphate dehydrogenase and hypoxanthine-guanine phosphoribosyltransferase activities in erythrocytes.