Single-channel Recordings of TREK-1 K+ Channels in Periodontal Ligament Fibroblasts

The periodontal ligament (PDL) works as a suspensory ligament when external mechanical stress is placed on the teeth. PDL fibroblasts, the principal cells in the PDL, are responsible for many PDL functions. We hypothesized that mechanosensitive ion channels are present in human PDL fibroblasts, which are capable of responding to mechanical stress during normal function of the tissue. Using patch-clamp techniques, we detected mechanosensitive TREK-1 K+ channels (a member of the two-pore-domain K+ channel family), whose single-channel conductance was 104 pS in symmetrical K+-rich solutions. The open probability of the channel was low in the quiescent state, but it was strongly increased by the induction of membrane stretch. Arachidonic acid also enhanced the channel activity. RT-PCR and immunocytochemical observations showed the expression of TREK-1 K+ channels in PDL fibroblasts. The results suggest that the activation of TREK-1 K+ channels by masticatory stress contributes to the hyperpolarization of PDL fibroblasts.

Characterization of pediatric Philadelphia-negative B-cell precursor acute lymphoblastic leukemia with kinase fusions in Japan

Recent studies revealed that a substantial proportion of patients with high-risk B-cell precursor acute lymphoblastic leukemia (BCP-ALL) harbor fusions involving tyrosine kinase and cytokine receptors, such as ABL1, PDGFRB, JAK2 and CRLF2, which are targeted by tyrosine kinase inhibitors (TKIs). In the present study, transcriptome analysis or multiplex reverse transcriptase–PCR analysis of 373 BCP-ALL patients without recurrent genetic abnormalities identified 29 patients with kinase fusions. Clinically, male predominance (male/female: 22/7), older age at onset (mean age at onset: 8.8 years) and a high white blood cell count at diagnosis (mean: 94 200/μl) reflected the predominance of National Cancer Institute high-risk (NCI-HR) patients (NCI-standard risk/HR: 8/21). Genetic analysis identified three patients with ABL1 rearrangements, eight with PDGFRB rearrangements, two with JAK2 rearrangements, three with IgH-EPOR and one with NCOR1-LYN. Of the 14 patients with CRLF2 rearrangements, two harbored IgH-EPOR and PDGFRB rearrangements. IKZF1 deletion was present in 16 of the 22 patients. The 5-year event-free and overall survival rates were 48.6±9.7% and 73.5±8.6%, respectively. The outcome was not satisfactory without sophisticated minimal residual disease-based stratification. Furthermore, the efficacy of TKIs combined with conventional chemotherapy without allogeneic hematopoietic stem cell transplantation in this cohort should be determined.

Long-term results of Tokyo Children's Cancer Study Group trials for childhood acute lymphoblastic leukemia, 1984-1999

We report the long-term results of Tokyo Children's Cancer Study Group's studies L84-11, L89-12, L92-13, and L95-14 for 1846 children with acute lymphoblastic leukemia, which were conducted between 1984 and 1999. The value of event-free survival (EFS)+/-s.e. was 67.2+/-2.2% at 10 years in L84-11, which was not improved in the following two studies, and eventually improved to 75.0+/-1.8% at 10 years in L95-14 study. The lower EFS of the L89-12 reflected a high rate of induction failure because of infection and delayed remission in very high-risk patients. The L92-13 study was characterized by short maintenance therapy; it resulted in poor EFS, particularly in the standard-risk (SR) group and boys. Females did significantly better than males in EFS in the early three studies. The gender difference was not significant in overall survival, partly because >60% of the males survived after the testicular relapse. Randomized studies in the former three protocols revealed that intermediate- or high-dose methotrexate therapy significantly reduced the testicular relapse rate. In the L95-14 study, gender difference disappeared in EFS. Contrary to the results of larger-scale studies, the randomized control study in the L95-14 reconfirmed with updated data that dexamethasone 8 mg/m(2) had no advantage over prednisolone 60 mg/m(2) in the SR and intermediate-risk groups. Prophylactic cranial irradiation was assigned to 100, 80, 44, and 44% of the patients in the studies, respectively. Isolated central nervous system relapse rates decreased to <2% in the last two trials. Secondary brain tumors developed in 12 patients at 8-22 years after cranial irradiation. Improvement of the remission induction rates and the complete omission of irradiation are currently main objectives in our studies.

Hematopoietic stem cell transplantation for Diamond-Blackfan anemia: a report from the Aplastic Anemia Committee of the Japanese Society of Pediatric Hematology

Transfusion-dependent Diamond-Blackfan anemia (DBA) patients opt for allogeneic hematopoietic stem cell transplantation (HSCT) as curative therapy. Clinical outcomes of 19 transplanted Japanese patients were analyzed. Prior to HSCT, 10 patients (53%) suffered hemosiderosis with organ dysfunction, and all eight with short stature (42%) had adverse effects of prednisolone. Median age at the time of HSCT was 56 months. Transplantation sources were 13 bone marrow [six human leukocyte antigen (HLA)-matched siblings, and six HLA-matched and one HLA-mismatched unrelated donors], five cord blood (two HLA-matched siblings and three HLA-mismatched unrelated donors), and one peripheral blood from haploidentical mother. All 13 patients with bone marrow transplantation (BMT) and two with sibling cord blood transplantation (CBT) had successful engraftment. Of three patients who underwent unrelated CBT, one died after engraftment, and the other two had graft failure but succeeded in a second BMT from an HLA-disparate father and unrelated donor, respectively. One died shortly after haploidentical PBSCT. The five-yr failure-free survival rate after BMT was higher than CBT (100%: 40%, p=0.002). Platelet recovery was slower in seven unrelated BMT than in six sibling BMT (p=0.030). No other factors were associated with engraftment and survival. These results suggest that allogeneic BMT, but not unrelated CBT, is an effective HSCT for refractory DBA.

A simplified sieve method for determining masticatory performance using hydrocolloid material

The purpose of this study was to develop a simplified technique for measuring masticatory performance by measuring the particle size distribution of masticated hydrocolloid impression material using a sieve method. Masticatory performance was defined as the rate of increase in the number of particles of masticated material on specific sieves with the increment in the number of chewing strokes. The number and weight of masticated hydrocolloid impression material on 10 sieves were compared with results for peanuts. The reproducibility of this method to determine masticatory performance was then examined. In seven sieves, there was a linear relationship between the number of particles and the number of chewing strokes for the hydrocolloid impression material; Pearson's correlation coefficient was higher for the hydrocolloid impression material than for peanuts. Measuring masticatory performance three times a day and three times every week revealed there were no differences in intra-individual variation in masticatory performance in six sieves. There was no significant difference between the masticatory performance calculated from two mastication tasks using the specific sieves and that calculated from seven tasks. These results suggest that this simplified sieve method using hydrocolloid materials can be reliably used for research purposes and in clinical situations.

Growth of human T cell acute lymphoblastic leukemia lymphoblasts in NOD/SCID mouse fetal thymus organ culture

The in vitro proliferation of T cell acute lymphoblastic leukemia (T-ALL) cells in its entirety has not been well delineated because of a lack of an appropriate culture system that mimics the growth pattern in a living body. We applied a NOD/SCID mouse fetal thymus organ culture (FTOC) for leukemic cells from fresh (one case) and frozen (seven cases) bone marrow (BM) samples of children with T-ALL. Cell growth was observed in all seven samples in the culture, reaching a proliferational peak at 4 weeks, and it was calculated that the proliferation potential was 212-to 319-fold. The FTOC-derived T-ALL cells showed similarity to the original cells morphologically and immunophenotypically, still possessed clonalities and were able to regenerate overt leukemia in NOD/SCID mice. These FTOC-derived T-ALL cells differed from ordinary cell lines because they always need FTOC support. Thus, we established a new in vitro culture for T-ALL cells. A comparison of the original and FTOC-derived T-ALL cells revealed that the proportion of cells expressing IL-7R increased in all seven cases. Sorting and re-seeding of FTOC-derived IL-7R+ and IL-7R- cells into secondary FTOC resulted in a predominant generation of IL-7R+ cells from both fractions, while IL-7R- cells proliferated more potently than did IL-7R+ cells, suggesting that a pathway for the conversion of IL-7R- to IL-7R+ exists during the proliferation of T-ALL lymphoblasts. Addition of exogenous IL-7 or neutralization with anti-IL-7 antibody did not influence the growth pattern of T-ALL cells in FTOC. The current study provides a unique assay system for the exploration of the hierarchy within human T-lymphoid leukemic cells, and should facilitate the establishment of novel therapeutic modalities.

Amicrobial pustular dermatosis in two patients with immunological abnormalities

We report two patients with severe amicrobial pustular dermatosis with immunological abnormalities: a 63-year-old woman with a 30-year-history of discoid lupus erythematosus and sicca syndrome, and a 35-year-old woman with high levels of gamma-globulinemia and positive antinuclear antibodies. Both patients presented with crusty and eroded erythematous plaques studded with aseptic pustules on the back, face, and scalp. Histological examination showed acanthosis, neutrophilic exocytosis to the epidermis, and neutrophilic and lymphocytic infiltration with nuclear dust in the dermis. These patients were diagnosed as having "amicrobial pustulosis associated with autoimmune diseases". The eruptions improved with combination treatment of oral prednisolone with cyclosporin A or diaminodiphenylsulphone. Although the pathogenesis remains unclear, amicrobial pustular dermatosis might be one of the cutaneous complications in autoimmune diseases.

Allogeneic bone marrow transplantation in first remission rescues children with Philadelphia chromosome-positive acute lymphoblastic leukemia: Tokyo Children's Cancer Study Group (TCCSG) studies L89-12 and L92-13

BACKGROUND

The prognosis of Philadelphia chromosome-positive acute lymphoblastic leukemia (Ph(+) ALL) is generally poor and reports from large studies are scarce. We evaluated the efficacy of allogeneic bone marrow transplantation (allo-BMT) for children with this type of leukemia.

PROCEDURE

The chemotherapy regimens consisted of an induction phase and very intensive consolidation followed by a reinduction phase and late intensification treatment. The selection of treatment modalities such as chemotherapy, allo-BMT, or autologous transplantation was made by each institute. The principal endpoint was the outcome of children with Ph(+) ALL according to the treatment options.

RESULTS

Thirty-two patients (4.3%) were diagnosed as Ph(+) ALL out of the 741 cases of ALL consecutively enrolled in two protocols of the Tokyo Children's Cancer Study Group (TCCSG) from 1989 to 1994. Thirty patients (93.8%) were induced into complete remission (CR). Of these 30 patients, eight children electively received allo-BMT in the first CR. Six of these patients are in continuous remission at a median follow-up of 58 (range 48-105) months after the diagnosis. One patient died following recurrence and another patient died of graft vs. host disease. Three patients treated with autologous BMT or peripheral blood stem cell transplantation in the first CR experienced a subsequent relapse. In the remaining 19 patients, 13 patients were treated with very high-risk chemotherapy alone and all relapsed within 28 months. One patient was excluded from the analysis because he was treated with standard-risk chemotherapy until relapse. The other five patients were also excluded from the analysis because Philadelphia chromosome was not detected until they relapsed. None of the relapsed patients survived in spite of treatment including allo-BMT. In multivariate analysis, only allo-BMT remained as an independent factor for good prognosis.

CONCLUSIONS

The only way to cure children with Ph(+) ALL was allo-BMT in this study and its outcome seemed promising.

Myelodysplastic syndrome in childhood: a retrospective study of 189 patients in Japan

We report a retrospective analysis of children with myelodysplastic syndrome (MDS) diagnosed between 1990 and 1997 in Japan. In total, 189 patients were enrolled: 122 cases of primary MDS (26 RA, 18 RAEB, 25 RAEBt, 53 CMML/JMML), 24 cases with constitutional predisposition to MDS, and 43 cases of therapy-related MDS (t-MDS). The frequency of pediatric MDS was estimated to be 7.7% of all leukemias. Cytogenetic abnormalities were observed in 41% of primary MDS and 90% of t-MDS cases. The 4-year survival rate, estimated by Kaplan-Meier analysis, for primary RA was 78.9%, while other types of MDS and JMML had rates lower than 40%, and t-MDS showed an even more unfavorable prognosis. In primary MDS, the survival rate of patients with cytogenetic abnormalities was significantly lower. Among prognostic variables by IPSS, only the cytogenetic pattern was useful for predicting outcome in childhood MDS. There was no apparent advantage to chemotherapy for RA, and the survival rate in patients with primary RA, JMML, or t-MDS receiving stem cell transplantation was significantly higher. More precise designs of our diagnostic and classification systems, as well as therapeutic trials in large-scale prospective studies, are necessary for further improvements in MDS outcome.

Sex-associated expression of mouse hepatic and renal CYP2B enzymes by glucocorticoid hormones

The expression of Cyp2b9 and Cyp2b10 genes was investigated in kidney, liver, and cultured hepatocytes of adult C57BL/6NCrj mice. The constitutive expression level of CYP2B mRNA in kidney was higher in female than in male mice, as it was in the liver where more CYP2B9 than CYP2B10 was expressed in the females, and more CYP2B10 was expressed in the males. After treatment with dexamethasone (Dex), induction of CYP2B10 mRNA and protein in the kidneys was far greater in male than in female mice. In contrast to Dex, phenobarbital (PB), pregnenolone-16 alpha-carbonitrile (PCN), and 1,1,1-trichloro-2,2-bis(p-chlorophenyl)ethane (DDT) did not induce the expression of the Cyp2b gene in the kidneys of either sex. In the liver, PB, PCN, and DDT induced both CYP2B9 and CYP2B10 in both sexes to the same extent, whereas Dex induced only CYP2B10 and simultaneously suppressed CYP2B9. Dex-inducible expression of CYP2B mRNA was decreased by 11 beta-[4-dimethylamino]phenyl-17 beta-hydroxy-17-[1-propynyl]estra-4,9-dien-3-one (RU-486), in both the kidneys and liver from male mice, and in cultured hepatocytes. However, RU-486 itself induced the expression of CYP2B mRNA in female liver and cultured hepatocytes. Interestingly, RU-486 increased PB-inducible expression of these species in cultured hepatocytes. Gonadectomy increased the expression of CYP2B mRNA in untreated male liver, but suppressed Dex-induced expression in the kidneys of both sexes. These observations suggest that (a) there are multiple regulatory pathways in the expression of Cyp2b genes, one of which used by Dex is mediated via the glucocorticoid receptor, which is different from that used by PB, and (b) sex hormones play a role in the regulation of the sex-dependent expression of Cyp2b genes in the mouse.

Delay of the diagnostic lumbar puncture and intrathecal chemotherapy in children with acute lymphoblastic leukemia who undergo routine corticosteroid testing: Tokyo Children's Cancer Study Group study L89-12

PURPOSE

To determine the effects of eliminating initial lumbar punctures in 418 consecutively treated children with acute lymphoblastic leukemia (ALL).

PATIENTS AND METHODS

Patients were enrolled onto a trial conducted in central Japan between 1989 and 1992. Treatment consisted of standard four-drug induction therapy followed by a risk-based intensification phase, reinduction therapy, late intensification, and remission maintenance therapy (total of 104 weeks). The initial lumbar puncture, with an intrathecal injection of chemotherapy, was performed after 1 week of prednisolone sensitivity testing (day 8). End points included response to prednisolone, CNS status at the time of the day 8 lumbar puncture, subsequent adverse events in CNS and bone marrow, and event-free survival (EFS).

RESULTS

The remission induction rate was 93.1% with a 6-year EFS rate (+/- SE) of 68.7% +/- 2.4%, which is similar to historical results for patients who received their diagnostic lumbar puncture and first instillation of intrathecal chemotherapy on day 0. Overall, 84.5% of the patients had good responses to prednisolone, whereas 15.5% had poor responses. Clinical outcome was strikingly better for the good responders (6-year EFS, 74.1% +/- 2.5% compared with 40.1% +/- 6.4% for patients with poor responses), suggesting that omission of intrathecal chemotherapy did not alter the predictive value of drug sensitivity testing. Eighteen patients experienced CNS relapse as their first adverse event (cumulative risk, 5.1%; 95% confidence interval, 2.7% to 7.4%), coincident with reports from groups using conventional strategies of CNS clinical management. Bleeding into the CSF at the time of the day 8 lumbar puncture was apparent in 29 cases (8.1%), but leukemic blasts were identified in only two.

CONCLUSION

Delay of the initial lumbar puncture and intrathecal injection of chemotherapy seems to be feasible in children with ALL. Further controlled evaluations are needed to establish the validity of this conclusion.

Evidence for linkage of familial Diamond-Blackfan anemia to chromosome 8p23.3-p22 and for non-19q non-8p disease

Diamond-Blackfan anemia (DBA) is a rare congenital hypoplastic anemia that usually presents early in infancy and is inherited in 10% to 20% of cases. Linkage analysis has shown that DBA in many of both dominant and recessive DBA families mapped to chromosome 19q13.2 leading to the cloning of a gene on chromosome 19q13.2 that encodes a ribosomal protein, RPS19. However, subsequently, mutations of the RPS19 gene have only been identified in 25% of all patients with DBA. This study analyzed 14 multiplex DBA families, 9 of which had 19q13.2 haplotypes inconsistent with 19q linkage. A genome-wide search for linked loci suggested the presence of a second DBA locus in a 26.4-centimorgan (cM) interval on human chromosome 8p. Subsequently, 24 additional DBA families were ascertained and all 38 families were analyzed with additional polymorphic markers on chromosome 8p. In total, 18 of 38 families were consistent with linkage to chromosome 8p with a maximal LOD score with heterogeneity of 3.55 at D8S277 assuming 90% penetrance. The results indicate the existence of a second DBA gene in the 26.4-cM telomeric region of human chromosome 8p23.3-p22, most likely within an 8.1-cM interval flanked by D8S518 and D8S1825. Seven families were inconsistent with linkage to 8p or 19q and did not reveal mutations in the RPS19 gene, suggesting further genetic heterogeneity. (Blood. 2001;97:2145-2150)

Immunosuppressive therapy using antithymocyte globulin, cyclosporine, and danazol with or without human granulocyte colony-stimulating factor in children with acquired aplastic anemia

A prospective multicenter trial of 119 children 1 to 18 years of age with newly diagnosed aplastic anemia (AA) was conducted, comparing treatment using antithymocyte globulin (ATG), cyclosporine (CyA), and danazol (DAN) with or without rhG-CSF (400 microg/m(2), day on days 1-90). All children with very severe AA received rhG-CSF (VSAA group, n = 50). The other children were randomized to receive ATG, CyA, DAN, and rhG-CSF (G-CSF+ group, n = 35) or ATG, CyA, and DAN without rhG-CSF (G-CSF- group, n = 34). After 6 months, the hematologic response rate was 71%, 55%, and 77% in the VSAA group, G-CSF+ group, and G-CSF- group, respectively. There was no difference in the incidence of febrile episodes and documented infections between the G-CSF+ and G-CSF- groups. Bone marrow transplantation (BMT) was attempted in 22 patients in whom initial immunosuppressive therapy (IST; n = 18) failed or in whom a relapse occurred after an initial response (n = 4). Nineteen of the 22 patients are alive and well after a median follow-up of 18 months (range, 3 to 66 months) since BMT. The probability of survival at 4 years was 83% +/- 7% in the VSAA group, 91% +/- 5% in the G-CSF+ group, and 93% +/- 6% in the G-CSF- group. Myelodysplastic syndrome (MDS)/acute myeloid leukemia (AML) developed in one patient in each of the three groups; the overall risk for MDS/AML was 3% +/- 2% at 4 years. Because the results of IST were encouraging, it is suggested that children with AA receive IST as first-line therapy if there is no human leukocyte antigen-matched sibling donor.

A novel female-specific member of the CYP3A gene subfamily in the mouse liver

Expression of a female-specific CYP3A in the adult mouse liver was observed on immunoblotting analysis. To characterize this cytochrome P450, we determined the primary structure of its cDNA and examined its expression profile. This cytochrome P450 consisted of 504 amino acids and showed 92, 68, 88, and 69% amino acid sequence identity with mouse CYP3A11, 3A13, 3A16, and 3A25, respectively, and was designated as CYP3A41, a new mouse CYP3A gene. In the female liver, levels of CYP3A41 mRNA expression were comparable to those of CYP3A11, the major CYP3A enzyme in the adult mouse liver. Expression of CYP3A41 mRNA was detected immediately after birth in the livers of animals of both sexes, but increased with age in females, whereas it was gradually reduced in males, resulting in predominantly female-specific expression in livers. Lesser amounts of CYP3A41 mRNA were detected in the kidneys of female mice, with traces in the stomach, ovary, and heart of female mice and in the testis of male mice. Gonadectomy and sex hormone treatment indicated that estradiol and testosterone were able to induce and suppress the expression of CYP3A41 mRNA in the liver, respectively. Among the classical CYP3A inducers, dexamethasone, rifampicin, and 3-methylcholanthrene did not affect the level of CYP3A41 mRNA in the liver of either sex. On the other hand, pregnenolone 16alpha-carbonitrile and phenobarbital suppressed CYP3A41 level to half that of untreated female mice. These observations indicated that CYP3A41 is a female-specific CYP3A and one of the major CYP3A forms in the female mouse liver.

An effective chemotherapeutic regimen for acute myeloid leukemia and myelodysplastic syndrome in children with Down's syndrome

In recent pediatric collaborative studies of acute myeloid leukemia (AML), patients with Down's syndrome (DS) have better outcome than other patients when they were treated according to their intensive AML protocols. This may be attributed to enhanced sensitivity of DS AML cells to selected chemotherapeutic agents. We evaluated a less intensive chemotherapeutic regimen which was specifically designed for children with AML-DS. Remission induction chemotherapy consisted of daunorubicin (25 mg/m2/day for 2 days), cytosine arabinoside (100 mg/m2/day for 7 days), and etoposide (150 mg/m2/day for 3 days). Patients received one to seven courses of consolidation therapy of the same regimen. Thirty-three patients were enrolled on the study and their clinical, hematologic and immunophenotypic features were analyzed. Of the 33 patients, all were younger than 4 years and diagnosed as having acute megakaryoblastic leukemia or myelodysplastic syndrome. All patients achieved a complete remission and estimated 8 year event-free survival rate was 80+/-7%. Three patients relapsed and two died due to cardiac toxicity and one due to septic shock. The results of our study showed that patients with AML-DS constitute a unique biologic subgroup and should be treated according to a less intensive protocol designed for AML-DS.

Plant regeneration from hairy roots induced by infection with Agrobacterium rhizogenes in Crotalaria juncea L

 Hairy roots were induced from leaf segments of Crotalaria juncea, which is used as a green manure crop antagonistic to nematodes, by infection with a mikimopine type wild strain of Agrobacterium rhizogenes A13 (MAFF02-10266). These roots exhibited vigorous growth and abundant lateral branching on half-strength Murashige and Skoog (1/2MS) medium without phytohormones. The adventitious shoots were induced from 30% of root segments 3 months after transfer onto medium containing 3 mg/l benzyl adenine. These shoots produced roots 1 month after transfer onto 1.2% agar-solidified 1/2MS medium without phytohormones. Regenerated plants were successfully grown under greenhouse conditions. The transgenic nature of the regenerated plants was confirmed by Southern-blot analysis.

Activation of transepithelial ion transport by secretin in human intestinal Caco-2 cells

Secretin stimulates bicarbonate secretion from pancreatic duct cells, but what influence secretin exerts on intestinal tissues remains to be clarified. The aim of this study is to examine effects of secretin on ion transport in intestinal epithelial Caco-2 cells. We mounted monolayers of Caco-2 cells grown on permeable supports for 21-28 d in a Ussing chamber and measured short-circuit currents (I(sc)). Addition of secretin (5-100 nM) to the basolateral solution dose-dependently induced biphasic increases of I(sc) (transient and sustained phase). Dibutyryl cyclic AMP (200 microM), forskolin (10 microM), and 3-isobutyl-1-methylxanthine (IBMX, 1 mM) also induced I(sc) responses similar to the administration of secretin. Addition of 5-nitro-2-(3-phenylpropylamino) benzoic acid (NPPB, 100 microM) or benzamil (100 microM) to the apical solution markedly reduced the secretin-induced I(sc) increase in the transient phase. A selective antagonist of cAMP-dependent protein kinase (PKA), N-[2-(p-bromocinnamylamino)ethyl]-5-isoquinolinesulfonamide (H-89, 1 microM), and a membrane permeable Ca(2+) chelator, 1, 2-bis(2-aminophenoxy)ethane-N,N,N',N'-tetraacetic acid tetrakis(acetoxymethyl ester) (BAPTA/AM, 10 microM) reduced the secretin-induced I(sc). Basolateral addition of 4, 4'-diisothiocyanostilbene-2,2'-disulfonic acid (DIDS, 1 mM) suppressed the sustained phase I(sc) increase. Secretin also induced alkalinization of the apical solution (DeltapH, 0.053 +/- 0.013). The alkalinization did not occur when DIDS (1 mM) was added to the basolateral solution or Na(+) was removed from the solutions. Taken together, our observations suggest: (1) secretin stimulates a benzamil-sensitive Na(+) influx and an NPPB-sensitive Cl(-) efflux across the apical membrane through PKA-dependent and Ca(2+)-sensitive pathways; and (2) secretin also induces alkalinization of the apical solution through the activation of a DIDS-sensitive Na(+)-HCO(3)(-) cotransport in the basolateral membrane of Caco-2 cells.

Six months of maintenance chemotherapy after intensified treatment for acute lymphoblastic leukemia of childhood

PURPOSE

We postulated that intensification of chemotherapy immediately after remission induction might reduce the leukemic cell burden sufficiently to allow an abbreviated period of antimetabolite therapy.

PATIENTS AND METHODS

Three hundred forty-seven children (ages 1 to 15 years) with previously untreated acute lymphoblastic leukemia (ALL) were enrolled onto the Tokyo L92-13 study, which excluded patients with mature B-cell ALL and patients less than 1 year old. One hundred twenty-four patients were classified as standard risk, 122 as high risk, and 101 as extremely high risk, according to age, peripheral-blood leukocyte count, selected genetic abnormalities, and immunophenotype. All subjects received four drugs for remission induction, followed by a risk-directed multidrug intensification phase and therapy for presymptomatic leukemia in the CNS. Maintenance chemotherapy with oral mercaptopurine and methotrexate was administered for 6 months, with all treatment stopped by 1 year after diagnosis.

RESULTS

The mean (+/- SD) event-free survival (EFS) and overall survival rates for all patients were 59.5% +/- 3.4% and 81.5% +/- 2.2%, respectively, at 5. 5 years after diagnosis. EFS rates by risk category were similar (60. 2% +/- 6.0% for standard risk, 57.7% +/- 5.6% for high risk, and 62. 5% +/- 5.7% for extremely high risk), whereas overall survival rates differed significantly (91.2% +/- 2.7%, 80.0% +/- 4.1%, and 72.1% +/- 4.5%, respectively, P <.0001 by the log-rank test). There were 107 relapses. Eighty-five (79.4%) of these 107 patients achieved second complete remissions, with subsequent EFS rates of 61.5% +/- 7. 9% (standard risk), 42.6% +/- 8.1% (high risk), and 9.6% +/- 6.4% (extremely high risk). Of the five risk factors analyzed, only the response to prednisolone monotherapy among extremely high-risk patients proved important.

CONCLUSION

Early treatment intensification did not compensate for a truncated phase of maintenance chemotherapy in children with standard- or high-risk ALL. However, 6 months of antimetabolite treatment seemed adequate for extremely high-risk patients who were good responders to prednisolone and received intensified chemotherapy that included high-dose cytarabine early in the clinical course.

Recovery of flagellar inner-arm dynein and the fertilization tubule in Chlamydomonas ida5 mutant by transformation with actin genes

The ida5 mutant of Chlamydomonas, first isolated as a mutant lacking a subset of axonemal inner-arm dyneins, has recently been shown to lack conventional actin owing to a serious mutation in its gene. It lacks inner-arm dyneins probably because actin is an essential subunit for their assembly. In addition, male gametes of ida5 are unable to produce the fertilization tubule, a structure that contains a core of actin filament bundles. To establish that those observed deficiencies are solely attributable to the loss of actin, and to provide a basis for future studies on the actin function in this organism, we examined in this study whether transformation of this mutant with cloned actin genes can rescue the mutant phenotypes. Cotransformation of the double mutant ida5arg2 with the wild-type actin gene and arginino-succinate lyase gene that suppresses the arg2 mutation yielded several transformants that displayed increased motility. All of them were found to have acquired the introduced actin gene in the genome and the product actin in the flagella, and regained the missing inner-arm dyneins and wild-type motility. In addition, most transformants also became able to grow the fertilization tubule when mating reaction was induced. In addition to the wild-type actin gene, we also used a chimeric actin gene in which the N-terminal 12 amino-acid sequence of Chlamydomonas actin was replaced by that of the greatly divergent Tetrahymena actin. Transformants with this gene also resulted in recovery of inner-arm dynein and 70-80% of the wild-type level of motility. These results established that the lack of inner-arm dynein and the fertilization tubule in ida5 are consequences of its loss of conventional actin. Furthermore, they demonstrate that Chlamydomonas offers an excellent experimental system with which to study the structure-function relationship of actin by means of mutant analysis.

[Trends of the biological monitoring measurements from 1991 to 1995]

Partial amendments to the Japanese Regulation on the Prevention of Lead Poisoning and that of Organic Solvent Poisoning were made in 1989. As a result, the measurement of blood lead and urinary delta-aminolevulinic acid (delta-ALA) became indispensable items of the occupational health examination for workers who handle lead. Also, the measurement of urinary metabolites of workers who handle eight kinds of organic solvents (xylene, N,N-dimethylformamide, styrene, tetrachloroethylene, 1,1,1-trichloroethane, trichloroethylene, toluene, and normal-hexane) became mandatory. The results of the biological monitoring mentioned above are classified into one of three categories, that is, distribution 1, 2 and 3, according to the concentration of the determinants. In this paper, the incidence of distribution 1, 2 and 3 of each determinant is reported and its change from 1991 to 1995 is discussed. The incidence of distribution 3 was 0.1-5.0% in each determinant. Although the ratio of distribution 1, 2 and 3 seems to have been almost the same for 5 years some determinants decreased their percentage of distribution 3. It is important to utilize the biological monitoring results for the improvement of working environments and working styles, and health management.

Synthesis of antibiotic-loaded interporous hydroxyapatite blocks by vacuum method and in vitro drug release testing

Interporous hydroxyapatite ceramic (Ca10(PO4)6(OH)2) has excellent bio-compatibility and interlinked pore structure, antibiotics could be loaded into pores in vacuum system. To confirm penetration of the agent to the HAb (2 cm3 cubic block), the aminoglycoside antibiotic (Isepamicin Sulfate; ISP) dissolved in eosin dye at various vacuum pressures. In ISP slow release study, the blocks were placed in 5 ml of PBS at a temperature of 37 degrees C. The PBS was replaced every 48 h and samples containing released ISP were stored until assay. All were found to release the drug maintaining a mean concentration of 0.41 microg ml(-1) even after 18 days of nine exchanges. This concentration of antibiotic exceeded the minimum inhibitory concentration against the common causative organisms of osteomyelitis. The results suggest that HAb impregnated with antibiotics using a simple vacuum system may serve as a valuable new method of administering local chemotherapy, primarily when used as a strut graft for bone defects.

A comparative study of the antinociceptive action of xenon and nitrous oxide in rats

We attempted to clarify the mechanism of antinociceptive action induced by xenon and nitrous oxide. Eighty percent of nitrous oxide or 80% xenon was applied to rats inside enclosed clear plastic glass cylinders with their tails protruding for assessment of the tail-flick response to radiant heat. With repeated testing, there was a rapid reduction to nitrous oxide antinociception within 90 min, which was interpreted as development of tolerance, but not to xenon antinociception. Nitrous oxide antinociception was blocked by the intraperitoneal administration of 0.1 or 1.0 mg/kg yohimbine, but not by 1.0 or 5.0 mg/kg L659-066 or by 5.0 or 10 mg/kg naloxone. Xenon antinociception was not affected by any of these drugs. Yohimbine and L659-066 are characterized as alpha 2-adrenoceptor antagonists. Although yohimbine penetrates the blood-brain barrier after systemic administration, L659-066 does not penetrate it and act peripherally. Therefore, the results indicate that alpha 2-adrenoceptors, but not opioid receptors, may play a key role in antinociception induced by nitrous oxide in the central nervous system. Furthermore, the mechanism of xenon antinociception differs from that of nitrous oxide because it does not involve either alpha 2 or opioid receptors.

IMPLICATIONS

The precise mechanism of antinociceptive action of nitrous oxide and xenon remains unknown. It is still controversial whether an opioid system plays a role in antinociception induced by nitrous oxide. The results of the study showed that antagonism of central alpha 2-adrenoceptors, but not opioid receptors, reverses the antinociception induced by nitrous oxide but not by xenon, which indicates that alpha 2-adrenoceptors may play a key role in nitrous oxide antinociception.

Myelodysplastic syndrome and acute myelogenous leukemia as a late clonal complication in children with acquired aplastic anemia

The improved outcome of acquired aplastic anemia (AA) has revealed later complications, such as myelodysplastic syndrome (MDS) and acute myelogenous leukemia (AML). We retrospectively analyzed 167 children with severe acquired AA. Eleven of 50 children treated with cyclosporin (CSA) and recombinant human granulocyte colony-stimulating factor (rhG-CSF) developed MDS/AML; 8 of these were within 36 months of the diagnosis of AA, much earlier than previous reports. Six of the 11 children received rhG-CSF exceeding 10 microg/kg/d, and 9 received rhG-CSF therapy for over 1 year. Ten children showed monosomy 7 at diagnosis of MDS. All of the 11 children were administered both CSA and rhG-CSF. There was no development of MDS/AML among 41 children treated with either CSA or rhG-CSF or among 48 children who underwent bone marrow transplantation. A well-controlled clinical trial is warranted to determine whether therapeutic modalities affect the development of MDS/AML in children with severe acquired AA.

Laser Doppler skin blood flow and sympathetic nervous responses to surgical incision during halothane and isoflurane anesthesia

The aim of the present study was to evaluate whether a sudden decrease in skin blood flow measured using a laser Doppler velocimeter reflects sympathetic nervous response to surgical skin incision during halothane (n = 17) and isoflurane (n = 16) anesthesia in 33 ASA physical status I or II patients scheduled for laparotomy. Plasma norepinephrine concentrations in the responding patients who showed a sudden decrease in the skin blood flow after surgical incision increased significantly and continued to increase 1-10 min after skin incision under halothane and isoflurane anesthesia. Although plasma norepinephrine concentrations in the nonresponders did not increase after surgical incision with halothane, the concentrations increased significantly at 1 min, but not at 3 and 10 min, after skin incision with isoflurane. The results indicate that the sudden decrease in laser Doppler flow reflects the sympathetic response to surgical incision. However, these also suggest that the factors that control the skin blood flow may not be simply sympathetic but may reflect other modulators as well. Plasma epinephrine concentration increased during skin incision, but the concentrations did not differ between the patients with and without a sudden decrease in skin blood flow. Increases in systolic blood pressure and rate-pressure product on skin incision were also significantly more in patients with skin blood flow response compared with those without the response. The magnitude of changes in plasma norepinephrine concentration and hemodynamic variables with skin incision was greater with isoflurane than with halothane at the same minimum alveolar anesthetic concentration level.

Cardiovascular effects of an ultra-short-acting nitric oxide-releasing compound, zwitterionic diamine/NO adduct, in dogs

BACKGROUND

This study was conducted to clarify the cardiovascular effects of a new NO-releasing compound, NOC-7, and to compare it with other nitrovasodilators, sodium nitroprusside (SNP) and nitroglycerin, in dogs anesthetized with pentobarbital.

METHODS AND RESULTS

A bolus injection of NOC-7 decreased mean aortic blood pressure in a dose-dependent manner. The onset was rapid and the recovery quick. Continuous infusion of NOC-7 decreased mean aortic pressure from 115 +/- 3.9 to 84 +/- 2.9 mm Hg and infusion of SNP, from 118 +/- 3.8 to 87 +/- 3.1 mm Hg. The optimum doses of NOC-7 and SNP were determined to be 2.73 +/- 0.77 and 11.5 +/- 6.1 micrograms.kg-1.min-1, respectively. During infusion of NOC-7, heart rate and cardiac output were increased (P < .05), pulmonary artery pressure was not changed, and systemic and pulmonary vascular resistances were decreased (P < .05). Electromagnetic flowmetry showed that portal venous and internal carotid arterial blood flow were increased (P < .05) and that hepatic and renal arterial blood flows were not changed. These hemodynamic changes during NOC-7 infusion were similar to those with SNP. The plasma level of NO2-/NO3 did not change, but methemoglobin increased slightly (P < .05). Comparison between hypotensive responses before and after a 3.5-hour infusion of NOC-7 or nitroglycerin showed that acute tolerance developed to nitroglycerin but not to NOC-7.

CONCLUSIONS

The results indicate that NOC-7 may be useful as an ultra-short-acting nitrovasodilator that has no major adverse effect or tolerance.

Effects of FSH on serum immunoreactive inhibin levels in the luteal phase of the menstrual cycle

OBJECTIVE

FSH causes a dose-related increase in circulating immunoreactive inhibin (INH) in the follicular phase of the menstrual cycle, while LH is the major stimulus to INH secretion by the corpus luteum. The present study was undertaken to assess whether FSH can also stimulate INH production during the luteal phase.

DESIGN

Normal volunteers were treated with a single injection of LH-free FSH (Metrodin, 150 units) or saline as control, during the early, mid- or late luteal phase of the cycle, with subsequent hormone measurements.

PATIENTS

The 21 volunteers were aged 19-29. Seven subjects given FSH and 8 controls were studied in the early luteal phase, 1-4 days post ovulation. Eight FSH treated subjects and 10 controls were studied in the midluteal phase, 5-9 days post ovulation, and 6 each, respectively, were studied in the late luteal phase.

MEASUREMENTS

Oestradiol (E2), progesterone (P), and INH were measured by previously described radio-immunoassays.

RESULTS

In both the early and mid-luteal phases, FSH caused a significant rise in INH (early, from 778 to 922 U/l, mid-luteal 1553 to 2090 U/l) and E2 (early 371 to 545 pmol/l, mid-luteal 528 to 636) while there was no significant change in P. No significant changes occurred in the saline treated subjects. In the late luteal phase FSH prevented the significant fall in INH seen in the controls, whilst there was no effect on E2 or P.

CONCLUSIONS

It was concluded that both FSH and LH are capable of modulating inhibin production during the luteal phase of the menstrual cycle. FSH may exert its actions on the corpus luteum or alternatively on developing follicles. The present study cannot clearly distinguish between these possibilities.

Inhibitory effect of acetylshikonin on the activation of NADPH oxidase in polymorphonuclear leukocytes in both whole cell and cell-free systems

The effects of acetylshikonin (AS) on the activation of NADPH oxidase (EC 1.6.99.6) in guinea pig polymorphonuclear leukocytes (PMNs) in both whole cell and cell-free activation systems were investigated. When PMNs were treated with AS before exposure to phorbol myristate acetate (PMA), superoxide (O2-) generation in these cells was significantly reduced, but after exposure of PMNs to PMA, inhibition of O2- generation by AS did not occur. Thiol compounds completely abolished the inhibitory effect of AS on the O2- generating activity of PMNs. In the cell-free system, AS inhibited the activation of NADPH oxidase induced by myristate in a combination of cytosol and membrane fractions obtained from intact PMNs, but did not inhibit the activity of NADPH oxidase already induced. These results suggest that AS inhibits the generation of NADPH oxidase complex in the activation of respiratory burst of PMNs, but does not directly inhibit the activity of NADPH oxidase already generated.

A new nitric oxide donor, NOC-18, exhibits a nociceptive effect in the rat formalin model

The utility of a new nitric oxide (NO) donor, NOC-18, and the contribution of the neurotransmitter NO to nociception in response to tissue injury in rats, were examined following the subcutaneous injection of formalin into the hindpaw. This model induces biphasic responses in pain-related behavior, such that C-fiber activation during the first phase triggers a state of central sensitization characterized by the second phase. Formalin-induced nociceptive behavior was facilitated by intracerebroventricular administration of NOC-18 in the second phase, but not the first phase. This enhancement was completely abolished by the soluble guanylate cyclase inhibitor, methylene blue. These findings indicate that NO causes nociception via the NO-cGMP pathway in the central nervous system and NOC-18 proved to be a convenient and useful tool for the investigation of nociception-related NO.

Ketamine inhibits nitric oxide production in mouse-activated macrophage-like cells

We have investigated the effects of ketamine on nitric oxide produced by activated macrophages using a murine macrophage-like cell line, J774. Cells were incubated for 18 h under stimulation with lipopolysaccharide and interferon-gamma or lipoteichoic acid and interferon-gamma, with various concentrations of ketamine (6-600 mumol litre-1). Nitric oxide production was assessed by measuring nitrite, a stable by-product of nitric oxide breakdown, in the medium. Other N-methyl-D-aspartate receptor antagonists, MK-801 (150 mumol litre-1) and dextromethorphan (150 mumol litre-1) were also tested. In addition, we studied the effects of ketamine on production of tumour necrosis factor-alpha by activated macrophages. Ketamine inhibited nitrite production dose-dependently with both lipopolysaccharide- and lipoteichoic acid-activated macrophages by up to approximately 65% at the highest ketamine concentration (600 mumol litre-1). Neither MK-801 nor dextromethorphan had an inhibitory effect. Ketamine also suppressed production of tumour necrosis factor-alpha. The data show that ketamine inhibited nitric oxide production by activated macrophages probably, in part, via inhibition of production of tumour necrosis factor-alpha, an autocrine stimulatory factor for nitric oxide production, but not via the NMDA receptor pathway, which is involved in neuronal nitric oxide production.

Inactivation of cholinesterase by ascorbic acid in the presence of cupric ions: a possible mechanism for the inactivation of an enzyme by the metal-catalyzed oxidation system

The mechanism of inactivation of cholinesterase (EC 3.1.1.8) by the Cu2+ -ascorbic acid (AsA) system was investigated. Incubation of the enzyme with the Cu2+ -AsA system under aerobic conditions resulted in an irreversible loss of enzyme activity. At low concentrations of Cu2+, the extent of inactivation showed the same dependence in accordance with the extent of oxidation of AsA. Saturation kinetics were observed with respect to the concentration of AsA. No change in the dissociation constant of the enzyme-AsA complex was observed at various concentrations of Cu2+. Catalase at a low concentration partially protected the enzyme from the inactivation, but did not affect the oxidation of AsA. In addition, catalase at a high concentration completely protected both the enzyme from inactivation and the AsA from oxidation. Both thiourea and thiocyanate completely protected the enzyme from the inactivation, while AsA was partially oxidized only in the initial phase. Our proposed mechanism for the inactivation of an enzyme by the Cu2+ -AsA system is as follows. A ternary complex involving the enzyme, Cu2+ and AsA is formed. This is followed by a redox reaction within the complex which generates a superoxide (.O2-) and hydrogen peroxide (H2O2). The H2O2 then reacts with .O2- in a Haber-Weiss reaction producing the hydroxyl radical (.OH). Another role of H2O2 is the conversion of the reduced Cu+ within the complex to Cu2+. Thus, repeated cycles of the redox reaction between the Cu2+ and AsA take place at the same locus, producing multiple .OH, which causes its complete inactivation.

Pulmonary resistance in dogs: a comparison of xenon with nitrous oxide

Xenon (Xe) may cause an increase in airway resistance due to its high density and viscosity. The object of this study was to examine the effects of Xe on pulmonary resistance using dog models with normal and methacholine-treated airways. During anaesthesia 22 mongrel dogs' tracheas were intubated and the lungs were mechanically ventilated with 70% N2/30% O2 as a control gas. The gases 70% nitrous oxide (N2O), 50% N2O, 70% Xe and 50% Xe were administered in a random order for 25 min. Bronchoconstriction was produced by a continuous infusion of methacholine, 0.22 mg.kg-1.hr-1. Pulmonary resistance (RL) was calculated by the isovolume method using flow at the airway opening, volume and transpulmonary pressure. In normal dogs, RL breathing 70% Xe (mean +/- SEM, 0.84 +/- 0.12 cm H2O.L-1.sec-1) was greater (P < 0.05) than with 70% N2O, 50% N2O or control gas (0.61 +/- 0.08, 0.59 +/- 0.06 and 0.62 +/- 0.06 cmH2O.L-1.sec-1). Breathing 50% Xe the RL (0.77 +/- 0.10 cmH2O.L-1.sec-1) was not different from 50% N2O or control. Methacholine infusion increased RL 3.92 +/- 1.98 (mean +/- SD) times. The RL breathing 50% Xe (2.55 +/- 0.44 cmH2O.L-1.sec-1) was not greater than during 50% N2O or control (2.08 +/- 0.33 and 2.13 +/- 0.33 cmH2O.L-1.sec-1) in methacholine-treated dogs. The data suggest that inhalation of high concentrations of Xe increases airway resistance, but only to a modest extent in dogs with normal or methacholine-treated airways.

NOC, a nitric-oxide-releasing compound, induces dose dependent apoptosis in macrophages

The ability of exogenous nitric oxide (NO) to induce apoptosis in macrophages was analyzed using NOC, a NO-releasing compound, as a source of NO. Exogenous NO was shown to induce apoptosis in a dose dependent manner. Quantitative analysis revealed that the amount of NO required to induce apoptosis in more than half of macrophages exposed was 100 times larger than that for endogenous NO-induced apoptosis. NOC proved to be a convenient and useful tool for investigation of apoptosis related to NO.

Primary structure of a coagulant enzyme, bilineobin, from Agkistrodon bilineatus venom

The amino acid sequence and disulfide bridge location of the coagulant enzyme, named bilineobin, isolated from the venom of Agkistrodon bilineatus was determined by Edman sequencing of the peptides derived from digests with cyanogen bromide, clostripain, Staphylococcus aureus V8 protease, trypsin, and chymotrypsin. This enzyme has a molecular weight of 57,000 Da by sodium dodecyl sulfate-polyacrylamide gel electrophoresis; however, bilineobin consists of 235 amino acids and has a calculated molecular weight of 26,481. The enzyme contains fucose, GlcNAc, galactose, mannose and NeuAc and six N-linked glycosylation consensus sites. The carboxyterminal amino acid, proline, was determined using carboxypeptidase Y. The six disulfide bonds of bilineobin link Cys78 to Cys234, Cys120 to Cys188, Cys178 to Cys203, Cys7 to Cys141, Cys152 to Cys167, and Cys28 to Cys44. The amino acid sequence similarity to flavoxobin (T.C. Shieh et al., 1988, J. Biochem (Tokyo) 103, 596-605) and batroxobin (N. Itoh et al., 1987, J. Biol. Chem. 262, 3132-3135) was 67%. The deglycosylated enzyme more rapidly generated fibrinopeptide A than native bilineobin.

Intracerebroventricular administration of a nitric oxide-releasing compound, NOC-18, produces thermal hyperalgesia in rats

This study was undertaken to define the role of nitric oxide (NO) in central nociceptive mechanisms by intracerebroventricular injection of an NO-releasing compound, NOC-18, in rats. The nociceptive threshold was evaluated by the radiant heat tail-flick test. Sixty-nine rats were divided into the seven groups, and the following drugs were injected intracerebroventricularly in 5 microliters of saline: no drug (control) (n = 13), 15 micrograms of NOC-18 (n = 15); 150 micrograms of NOC-18 (n = 9); 100 micrograms of N-nitro-L-arginine methyl ester (L-NAME) (n = 8); 15 micrograms of NOC-18 + 100 micrograms of L-NAME (n = 8); 10 micrograms of methylene blue (MB) (n = 8); 15 micrograms of NOC-18 + 10 micrograms of MB (n = 8). NOC-18 caused a dose-dependent curtailment (7% and 23% decreases for 15 micrograms and 150 micrograms of NOC-18, respectively) of the tail-flick latency during the period from 15 to 120 min. L-NAME caused prolongation (15% maximum) of the tail-flick latency during the period from 15 to 150 min. However, NOC-18-induced hyperalgesia was not influenced by L-NAME. MB also caused prolongation (9% maximum) of the tail-flick latency during the period from 15 to 150 min, and completely blocked the hyperalgesia induced by 15 micrograms of NOC-18. These findings indicate that the NO-cGMP pathway is directly involved in thermal hyperalgesia in the brain.

Nonenzymatic glycation of transferrin: decrease of iron-binding capacity and increase of oxygen radical production

The total iron-binding capacity (TIBC) and iron contents of diabetic rat serum, as well as the iron-binding capacity of glycated transferrin and oxygen radical production by the glycated proteins were examined. The TIBC and iron content of diabetic rat sera were found to be much lower than those of control rat sera. Incubation of human serum with glucose in vitro resulted in a significant fall of its unsaturated iron-binding capacity (UIBC) with time. When apotransferrin was incubated with glucose, its UIBC significantly decreased. The iron content of holotransferrin was markedly reduced by incubation with bathophenanthroline sulphonic acid (BPSA) in the presence of glucose, although the content was not altered by incubation with BPSA alone. The generation of superoxide radical (O2-) and hydroxyl radical (OH.) by the glycated holotransferrin was much greater than that by glycated apotransferrin. Glycated holotransferrin showed significantly accelerated hydroxyl radical production by the hypoxanthine-xanthine oxidase system, while intact holotransferrin did not. Treatment of holotransferrin with glucose caused the fragmentation of the protein, while the same treatment of apotransferrin did not. These results suggest that iron ions in the glycated transferrin molecule are bound loosely to the protein and are redox-active and the glycated holotransferrin produces oxygen radicals including O2- and OH. efficiently, and that the glycated transferrin does not function as an iron-binding protein.

A case report of nephrotic syndrome associated with rifampicin therapy

We describe nephrotic syndrome occurring in a 53-year-old male patient on continuous rifampicin (RFP) therapy for pulmonary tuberculosis. After the pulmonary tuberculosis was improved by chemotherapy that included RFP, administration of Isoniazid and RFP was continued. After 16 weeks, he suddenly developed nephrotic syndrome, but never developed acute renal failure. He was admitted to hospital and renal biopsy was performed revealing minor glomerular abnormalities and few interstitial changes in light microscopy. No positive immunofluorescent microscopic findings were obtained without fibrinogen. Thus, minimal change nephrotic syndrome (MCNS) was diagnosed. In contrast, electron microscopy showed several injurious glomerular changes, such as the elevation of the endothelial layer, local widening of the subendothelial space which was filled with fine granular or fibrillar materials, irregularity of the endothelial investment, swelling or shrinkage of the endothelial cells, compatible with those seen in many diseased conditions supposedly caused by clinical or subclinical localized intravascular coagulation. Discontinuation of RFP administration completely relieved the patient of MCNS with the aid of predonisolone therapy. Thus, this patient might not have been a case of incidental, but rather drug (RFP)-induced MCNS.

Hydroxylation of phenylalanine and salicylate by stimulated polymorphonuclear leukocytes and the accelerating effect of glutathione on their hydroxylation

Incubation of phorbol-myristate acetate-stimulated human polymorphonuclear leukocytes (PMNs) with phenylalanine and salicylate induced significant levels of formation of o- and m-tyrosines, and 2,3- and 2,5-dihydroxybenzoates (DHBAs), respectively, dependent on reaction time. Aromatic hydroxylation reactions were not inhibited by desferrioxamine, nor were they affected by the removal of trace ion contamination from the buffer solution used by treatment with conalbumin. Hydroxylation reactions were largely blocked by superoxide dismutase and hydroxyl radical (OH.) scavengers. The results of the present study suggest that the generation of OH. by human PMNs occurs during the respiratory burst. Hydroxylation of both phenylalanine and salicylate by stimulated human PMNs were significantly accelerated by incubation in the presence of the reduced form of glutathione (GSH). Hydroxylation of phenylalanine by stimulated guinea pig PMNs in the presence of GSH was significantly inhibited by desferrioxamine, although the same hydroxylation in the absence of GSH was not affected. Hydroxylation of phenylalanine by the hypoxanthine (HX)-xanthine oxidase (XO) system by intact PMNs was significantly accelerated by the addition of GSH, although that in the absence of PMNs was largely inhibited. Desferrioxamine showed an inhibitory effect on hydroxylation by the HX-XO system in the presence, but not in the absence, of intact PMNs. The results suggest that the formation of OH. by stimulated PMNs is accelerated by GSH, based on the occurrence of the Harber-Weiss reaction catalyzed by transition metal ions liberated and reduced by GSH from PMNs, and by the effective accumulation of H2O2 by the GSH-induced inhibition of catalase.

On the mechanism of inactivation of active papain by ascorbic acid in the presence of cupric ions

An inactivation mechanism of active papain (EC 3.4.22.2) by the Cu(2+)-ascorbic acid (AsA) system was examined. Incubation of active papain, which contains an active sulfhydryl (SH) group, with the Cu(2+)-AsA system under aerobic conditions resulted in an irreversible loss of enzyme activity. The enzyme was not inactivated at a molar ratio of enzyme to Cu2+ of 1:< 1, whereas at a molar ratio of 1:1-2, the extent of inactivation showed the same dependence on the extent of oxidation of AsA. Saturation kinetics were observed with respect to the concentration of AsA. The degree of inactivation was dependent on the decrease in SH content of the enzyme. Catalase at a low concentration partially protected the enzyme from inactivation, but did not affect the oxidation of AsA. In addition, catalase at a high concentration completely protected both the enzyme from inactivation and AsA from oxidation. The present results suggest that an additional function of H2O2, besides producing hydroxyl radicals (.OH), is to promote the conversion of Cu+ into Cu2+, and that an active SH group of papain is site-specifically modified by the .OH, resulting in inactivation of the enzyme.

Effect of radical scavengers on the inactivation of papain by ascorbic acid in the presence of cupric ions

Incubation of papain (EC 3.4.22.2) with ascorbic acid (AsA) and Cu2+ in acetate buffer (pH 5.6) results in an irreversible loss of enzyme activity by site-specific generation of free radicals [H. Kanazawa, S. Fujimoto, A. Ohara, Biol. Pharm.Bull., 16, 11 (1993)]. In this study, the effect of some compounds, known free radical scavengers, on the relationship between the inactivation of papain by the Cu(2+)-AsA system and the oxidation of AsA was investigated. Catalase completely protected the enzyme from inactivation by the Cu(2+)-AsA system, although hydrogen peroxide (H2O2) by itself, known to be generated during the autoxidation of AsA, did not inactivate the enzyme. The oxidation of AsA was unaffected by catalase. Both thiourea and sodium thiocyanate completely protected the enzyme from inactivation, while AsA was partially oxidized only in the initial stage. In the presence of potassium iodide, both the inactivation of the enzyme and the oxidation of AsA were characterized by a rapid initial phase followed by a stable phase where no reaction took place and, subsequently, a slower phase. Histidine partially prevented the inactivation of the enzyme and the oxidation of AsA. The present results suggest that H2O2 serves as a source of secondary, highly reactive species, probably hydroxyl radicals, which are responsible for the inactivation, and that the protection from inactivation by some radical scavengers, such as thiourea, sodium thiocyanate, potassium iodide, and histidine, is based on the removal of metal ions (Cu2+ or Cu+) at the specific site of inactivation.

Study on the acceleration in healing of ethanol-induced gastric lesions in rats by methylprednisolone

This study was designed to determine the influences of methylprednisolone (MP, CAS 2375-03-3) on the genesis and healing of gastric lesions induced by 50% ethanol in relation to the changes in gastric mucosal prostaglandin (PG) and leukotriene (LT) contents and vascular permeability. Intragastric administration of 1 ml of 50% ethanol induced hemorrhagic lesions in the fundic portion, and these lesions were not affected by 20 mg/kg of MP injected subcutaneously 30 min before ethanol administration. In untreated rats, 4 kinds of PGs, i.e., 6-keto-PGF1a, PGF2a, PGE2, and PGD2, were determined in gastric mucosa by high performance liquid chromatography (HPLC), but no LTs were detected. Administration of ethanol significantly reduced all PG contents and increased production of peptide-LTs in gastric mucosa. Pretreatment with MP did not influence ethanol-induced changes in PG and peptide-LT contents. Ethanol-induced lesions required 96 h for total healing. Ulcer healing was not affected by MP, which was injected subcutaneously twice daily from 1 h after ethanol administration until the end of the experiment, and complete ulcer healing was observed after 72 h. MP did not affect ethanol-induced decrease in PG contents, their recoveries, or peptide-LT contents. Ethanol increased vascular permeability and MP reduced this increase. These results suggest that MP does not have a hazardous effect, but is rather beneficial with regard to healing of ethanol-induced gastric lesions through prevention of the increase in vascular permeability caused by ethanol, and that it affected neither gastric mucosal PG nor peptide-LT contents.

Characterization and amino-terminal sequence of phospholipase A2-II from the venom of Agkistrodon bilineatus (common cantil)

1. Phospholipase A2 was isolated from the venom of Agkistrodon bilineatus by Sephadex G-75 and CM-Cellulose column chromatographies. 2. The purified phospholipase A2 gave a single band on disc polyacrylamide gel electrophoresis, sodium dodecyl sulfate polyacrylamide gel electrophoresis and ODS-HPLC. 3. The enzyme preparation had a mol. wt of 14,000, isoelectric point of pH 10.12 and possessed 121 amino acid residues. 4. The enzyme hydrolyzed the phospholipids phosphatidyl choline, phosphatidyl ethanolamine, phosphatidyl inositol and phosphatidyl serine. 5. The contraction of mouse diaphragm was inhibited by phospholipase A2-II. 6. Phospholipase A2 activity of this preparation was inhibited by ethylenediamine tetraacetic acid, ethyleneglycol (beta-aminoethyl) N,N,N',N'-tetraacetic acid, p-bromophenacyl bromide or N-bromosuccinimide, but not by iodoacetic acid or diisopropyl fluorophosphate. 7. The amino-terminal sequence of the PLA2-II was determined.