Mutant isolation of the Escherichia coli quinoprotein glucose dehydrogenase and analysis of crucial residues Asp-730 and His-775 for its function

Several mutants of quinoprotein glucose dehydrogenase (GDH) in Escherichia coli were obtained and characterized. Of these, significant mutants were further characterized by kinetic analysis after purification or by site-directed mutagenesis to introduce different amino acid substitutions. H775R and H775A showed a pronounced reduction of affinity for a prosthetic group, pyrroloquinoline quinone (PQQ), suggesting that His-775 may directly interact with PQQ. D730N and D730A showed low glucose oxidase activity without influence on the affinity for PQQ, Mg2+, or substrate, but D730R showed reduced affinity for PQQ. The spectrum of tryptophan fluorescence revealed that the local structure surrounding PQQ was not changed by D730N mutation. Based on these data, we assume that Asp-730 may occur close to PQQ and function as a proton (and also electron) donor to PQQ or acceptor from PQQH2. Substitutions of Gly-689, that are located at the end of a unique segment of GDH among homologous quinoprotein dehydrogenases, directed reduction of the affinity for PQQ or GDH activity. Therefore, the unique segment and Asp-730 may play a specific role for GDH, which might be related to the intramolecular electron transfer from PQQ to ubiquinone.

[Significance of full-thickness chest wall resection as a local treatment for sternum metastasis of breast cancer]

Bone metastasis of breast cancer generally tends to be multiple. However, breast cancer frequently metastasizes to the sternum as solitary metastasis. Resection of the sternum was reported to be an effective surgical technique for sternum metastasis which could not be remarkably improved by chemo-endocrine therapy and locoregional recurrent breast cancer invading the skin. A first patient was diagnosed with sternum metastasis invading the skin 44 months after radical mastectomy for breast cancer of stage II. A second patient had breast cancer of stage IV simultaneously with metastases to the sternum and the lung. Only the lung metastasis was successfully controlled by chemo-endocrine therapy, but the sternum metastasis was progressive, following radical mastectomy. Both patients manifested solitary bone metastases and underwent full-thickness chest wall resection. The defect of the chest wall was reconstructed with the mucocutaneous flap using the dorsal latissimus muscle in case 1 and with the abdominal rectus muscle in case 2. Twenty months after the resection of the sternum, the first patient suffered from supraclavicular lymph node metastasis, and the multidisciplinary treatment including radiation therapy was indicated. This therapeutic procedure was effective, and the patient survived for 63 months after resection of the sternum. The second patient has made good progress for six months in maintaining complete remission with chemo-endocrine therapy. These findings suggested that surgical resection was a useful local treatment for solitary sternum metastasis.

[Management of errors in hospital laboratories--Total Quality Control and lists]

Errors in the daily routine work of a hospital laboratory vary. Therefore, measures to prevent errors must be devised. It is important to perform Total Quality Control (TQC) and to provide reliable diagnostic information and this does not stop at quality control of mere assay value, but extends to consideration of the correspondence to a patient. It is absolutely necessary to reduce errors in a laboratory and to perform TQC steadily. Therefore, the concept of TQC is divided roughly as follows 1) Safe management, 2) Technical management, 3) Information management, 4) Materials management. These categories are then subdivided even further. These categories relate to error management because it is considered that the manuals for technical and information management are important. It is necessary to create an error processing ledger to collect information for error management for TQC and for prevention of errors in investigating causes and to record all processes according to the contents of the error. Such records can be used to prevent recurrences. Thereby, not only prevention of errors but also improvements in the accuracy and reliability of information offered are thought to become possible.

[Intraoperative interstitial microwave therapy for recurrent hepatocellular carcinoma of the caudate lobe: a case report]

Microwave tissue coagulation (MTC) therapy was given patients with recurrent hepatocellular carcinoma (HCC) of the caudate lobe of the liver, in which radical surgery for deteriorated liver function was impossible. A total of 40 MTC sessions was applied to two tumors under laparotomy. MTC was administered for 20 seconds in each session. Microwave energy output was 70 watts for 15 mm needle-electrodes and 100 watts for 30 mm electrodes. Alpha-fetoprotein levels in serum had decreased after surgery. Abdominal computed tomography showed no blood flow whatsoever in tumors undergoing MTC. There are fewer limits to the sites and angles for insertion of electrodes under laparotomy. Thus, the surgical approach provides access to all parts of the liver for treatment. We conclude that intraoperative MTC is highly effective in tumor necrosis, and can be a useful local treatment for nonresectable HCC.

Optimism, social support, stress, and physical and psychological well-being in Japanese women

The present study examined the relationship between self-reported scores on optimism, social support, and stress and on physical and psychological well-being in 176 Japanese female college students. The significant interactions found among scores on optimism, social support, and stress suggest that individuals who reported higher optimism and social support also rated themselves higher with respect to physical and psychological well-being, regardless of their reported stress.

Pure red cell aplasia during carbamazepine monotherapy

A 7-year-old girl developed pure red cell aplasia during carbamazepine (CBZ) monotherapy for epilepsy. She developed generalized clonic convulsions at the age of 7 years and 8 months. Treatment with CBZ was begun. Two months later she was admitted to our hospital because of severe anemia. Bone marrow examination revealed the almost complete absence of erythroblasts, with normal myelopoiesis and megakaryocytopoiesis, indicating pure red cell aplasia. Following the discontinuation of CBZ, she developed brisk reticulocytosis within 1 week and her hemoglobin level rose to a normal one within 1 month. Although the hematological toxicity of CBZ is well documented, isolated cessation of red cell production is uncommon. A patient who is undergoing treatment with CBZ should be carefully monitored, especially for serious adverse reactions including pure red cell aplasia.

Optimism, Type A behavior, and psychological well-being in Japanese women

The relations of self-report scores for optimism, Type A behavior, and stress with those for depression and anxiety were examined in 144 Japanese female college students. A significant interaction of scores on optimism and Type A behavior indicated that subjects who reported higher optimism and higher Type A behavior had a lower mean for anxiety than those who reported lower optimism and higher Type A behavior.

Nitric oxide and immune complexes are involved in the induction of a novel luminol chemiluminescence in cytotoxic macrophages

A chemiluminescence (CL) was observed immediately after the addition of luminol to thioglycollate-elicited ICR mouse peritoneal macrophages (M phi) that had been incubated overnight with recombinant murine interferon-gamma (IFN-gamma) and lipopolysaccharides (LPS). The intensity of this CL was closely correlated with the cytotoxic activity of M phi. NG-monomethyl-L-arginine (L-NMMA), an inhibitor of nitric oxide (NO) synthase, inhibited the induction of this CL, and L-arginine restored the L-NMMA-induced inhibition. These results suggest that NO is directly involved in the induction of CL. However, we found that immune complexes are required for the induction of CL as well as NO.

Seroepidemiological study of Toxoplasma infection in central and western regions in Nepal

The present study was carried out to ascertain the seroprevalence rate in different geographical areas in Central and Western Regions in Nepal. A total of 1,237 serum samples collected from Nuwakot (217), Kathmandu valley (402) and Chitawan (159) districts in Central Region, and Mustang (143), Surkhet (64) and Banke (252) districts in Western Region in Nepal were included in this study. Toxoplasma antibodies were detected by micro-latex agglutination (MLA) and enzyme linked immunosorbent assay (IgM-ELISA) methods. The seropositive rate in Central and Western Regions were found to be 48% and 49%, respectively; with an overall positive rate of 48 percent. Districtwise, the seropositive rate in Nuwakot, Kathmandu valley, Chitawan, Mustang, Surkhet and Banke districts were 38, 46, 64, 51, 67 and 44%, respectively. Interestingly, the relatively newly inhabited Surkhet district in Western Region and Chitawan district in Central Region showed significantly higher seropositive rate compared with those of two other districts in the respective Regions (p < 0.05). Ethnically, Tibeto-Burmans showed higher seropositive rates in Central Region (p > 0.05). In contrast, Indo-Aryans showed higher seropositive rate in Western Region (p > 0.05). Age related increase in seropositivity was observed only in Central Region. One percent of Toxoplasma antibody positive samples also showed Toxoplasma IgM antibody positivity.

[SPECT, MRI and EEG in infants with lissencephaly]

Single photon emission tomography (SPECT), MRI and EEG were studied in two infants with lissencephaly. One infant had generalized tonic convulsions at 7 month of age and continuous high voltage fast activities on EEG. The other infant developed infantile spasms at the age of 2.5 months, and showed low voltage disorganized background with pseudorhythmic high voltage sharp waves on EEG. Cranial CT and MRI in both infants revealed abnormally thick cortex, dilatation of the lateral ventricles, and smooth or relatively smooth cerebral surface. In SPECT studies, a diffuse increase of tracer uptake was shown at the cerebral cortex compared with the basal ganglia or cerebellum in both infants. The SPECT finding might reflect the abnormal cortical architectures in this cerebral malformation.

The Bean Seed Storage Protein [beta]-Phaseolin Is Synthesized, Processed, and Accumulated in the Vacuolar Type-II Protein Bodies of Transgenic Rice Endosperm

The seed storage protein [beta]-phaseolin of the common bean (Phaseolus vulgaris L.) was expressed in the endosperm of transgenic rice (Oryza sativa L.) plants. The 5.1- or 1.8-kb promoter fragment of the rice seed storage protein glutelin Gt1 gene was fused transcriptionally to either the genomic or cDNA coding sequence of the [beta]-phaseolin gene. The highest quantity of phaseolin estimated by enzyme-linked immunosorbent assay was 4.0% of the total endosperm protein in the transgenic rice seeds. The phaseolin trait was segregated as a single dominant trait with a positive gene dosage effect and was stably inherited through three successive generations. Both phaseolin genomic and cDNA coding sequences were used to synthesize four isoforms of mature phaseolin protein with apparent molecular masses of 51, 48, 47, and 45 kD. Enzyme deglycosylation experiments indicated that the 51-kD form contains high-mannose N-glycans; the 48- and 47-kD forms have further modified N-glycans; and the 45-kD form is a nonglycosylated protein. Immunolabeling studies using light and electron microscopy demonstrated that phaseolin accumulates primarily in the vacuolar type-II protein bodies located at the periphery of the endosperm near the aleurone layer. We discuss the implications of these results on nutritional improvement of rice grains.

The use of PCR in detecting toxoplasma parasites in the blood and brains of mice experimentally infected with Toxoplasma gondii

Polymerase chain reaction (PCR) has been extensively used for diagnosis recently because of its very high sensitivity and specificity. We studied the applicability of PCR to the early diagnosis of toxoplasmosis in a murine model orally infected with Toxoplasma gondii (S-273). PCR was performed using EH24 and HE27 primers synthesized by the phosphoramidite method. Mice blood and brains collected on various post infection days (PID) were analysed by PCR (35 cycles). A portion of the brain tissue from each mouse was examined microscopically for the presence of parasite cysts. Blood and brain PCR were positive on the 9th and 12th day post-infection (DPI). Toxoplasma cysts in brain tissue appeared only on the 18th PID. The results showed that Toxoplasma parasites can be detected earlier in the blood than in the brain during primary infection, indicating that blood PCR is the more useful procedure.

Structure and differential response to abscisic acid of two promoters for the cytosolic copper/zinc-superoxide dismutase genes, SodCc1 and SodCc2, in rice protoplasts

We determined the 5'-flanking sequences of two nuclear genes (SodCc1 and SodCc2) encoding cytosolic copper/zinc-superoxide dismutase in rice (Oryza sativa L.). Utilizing transient beta-glucuronidase (GUS) reporter assays, functional promoter-GUS analysis was performed in rice protoplasts exposed to the phytohormone abscisic acid (ABA) or the antioxidant sulfhydryl reagent, dithiothreitol (DTT). Transcriptional activities from both SodCc-GUS fusions were stimulated by DTT, which induces the promoter activity of the tobacco SodCc gene [Proc. Natl. Acad. Sci. USA 90 (1993) 3108-3112]. ABA had no effect on SodCcl-GUS expression but specifically induced the gene expression of the SodCc2-GUS fusion. The simultaneous application of ABA and gibberellin A3, however, abolished the enhancing effect of ABA. These results indicated that two rice SodCc promoters differentially respond to externally supplied ABA and that one of the regulatory factors for plant SodCc expression is ABA in addition to cellular redox-modulating antioxidants.

Seroprevalence of hepatitis B and C viruses in eastern Nepal

The seroprevalence of hepatitis B virus (HBV) and hepatitis C virus (HCV) in 303 serum samples collected from that apparently healthy population inhabitating different areas in eastern Nepal was studied. Samples were collected at Dharan Municipality, Sunsari85), Pancha Kanya Village Development Committee, Ilam86), Dhankuta Hile, Dhankuta82) and Basantapur Village Development Committee, Tehrathm50). HBsAg and anti-HBsAg antibody was screened by reverse passive haemagglutination (RPHA) and passive haemagglutination (PHA) respectively and positivity was confirmed by enzyme linked immunosorbent assay (ELISA). Anti-HCV antibody was detected by ELISA. None of the samples were positive for HBsAg. Anti-HBsAg antibody was positive in 1.9% (6/303). The positive rate increased with age reaching 25% positivity among the elderly. The anti-HBsAg antibody positivity was 2.35, 2.32, 1.22 and 2.00 in Dharan, Ilam, Dhankuta and Tehrathum respectively Anti-HCV antibody was detected only in one sample (15-year-old boy) collected in Dharan. These findings indicate that the HBV and HCV infections are not active in eastern Nepal.

Immunoglobulin M and G antibodies in mice in response to Toxoplasma gondii (S-273) infection and their antigen recognition patterns in western blotting on various post-infection days

Immunoglobulin M and G antibody responses in mice experimentally infected with Toxoplasma gondii (S-273) and the reaction patterns with T. gondii (RH) tachyzoite antigens were studied on various post-infection days (PIDs) (2nd to 36th PIDs) using a commercially available IgM and IgG enzyme linked immunosorbent assay (ELISA) test systems and Western blotting (WB) technique. IgM antibody in ELISA test appeared to be positive on 12th PID (absorbance 0.764) and reached its peak level on 16th PID (absorbance 1.338) showing a slow decline thereafter with an absorbance of 0.800 even on 36th PID. Positivity of IgM was confirmed by WB except for 36th PID. IgG appeared on 16th PID with an absorbance of 0.248 and showed a steady increasing tendency even on 36th PID (absorbance 1.747). However, IgG positivity on WB was observed only on 29th PID and afterwards. On Western blots, both IgM and IgG showed interesting antigen recognition patterns on various PIDs. At the most IgM recognised seven antigens of 14kDa to 53kDa while IgG recognised eight antigens of 17kDa to 53kDa. Major antigens recognised by IgM were of 53kDa and 21kDa while the major band recognised by IgG was of 19kDa. The major bands, however, showed variability in their consistency during various PIDs. All the antigens recognised by IgM and IgG were not identical.

Seroepidemiological study of toxoplasmosis in two different geographical areas in Nepal

A total of 302 serum samples collected from Chitawan (159) and Mustang (143) districts of Nepal were included in this study. Anti-toxoplasma antibody was detected using micro-latex agglutination (MLA) and ELISA methods. An overall positive rate was found to be 57.9%. The positive rate in Chitawan was significantly higher (64.1%) (less than 1,000 m altitude) compared to that in Mustang (51.0%) (more than 3,000 m altitude) (p < 0.05). Females in Chitawan showed significantly higher positive rate (71.2%) compared to males (56.9%) (p < 0.05). On the contrary, though insignificantly, males showed higher positive rate (57.9%) compared to that of females (43.3%) in Mustang. Almost equal positive rate was observed among males in both study area. Females in Chitawan showed significantly higher (71.2%) positive rate compared to their counterparts in Mustang (43.3%) (p < 0.001). A slight increase in positive rate with age was observed in Chitawan while in Mustang a decreasing trend was noticed. Ethnically though statistically not significant, Indo-Aryans showed a higher positive rate (69.2%) compared to the positive rate shown by Tibeto-Burmans (63.1%) in Chitawan while the reverse was true in Mustang (Tibeto-Burmans: 53.8% and Indo-Aryans: 38.4%). Interestingly, 2.9% and 1.3% of MLA positive samples showed toxoplasma IgM antibody. None of the IgM positive samples were positive for toxoplasmic antigens.

Status of soil-transmitted helminthic infection in Nepal

A retrospective evaluation of the status of soil-transmitted helminthic infection in Nepal during the period from 1985 to 1992 was conducted at the Parasitology Laboratory, Department of Pathology, TU Teaching Hospital in Kathmandu. An average of 6,537 faecal samples were examined each year for the presence of various types of intestinal parasites. The annual rate of positivity of these samples for soil-transmitted helminthiasis ranged from 18.0 to 36.6%. The annual incidence decreased every successive calendar year in both adults and children, irrespective of sex. Among the various types of helminths, the most common was Ascaris lumbricoides (roundworm), followed by hookworm. The incidence of A. lumbricoides remained constant throughout the study period, while that of other parasites markedly decreased each year.

The relationship between the ambulatory variability and the laboratory reactivity of blood pressure and heart rate

We examined the relationship between the ambulatory variability and the laboratory reactivity of systolic blood pressure (SBP), diastolic blood pressure (DBP) and heart rate (HR) in 21 male college students. The mean increase during the waking period from that during sleep was defined as variability 1, and the standard deviation of the ambulatory measurements during waking was defined as variability 2. The reactivity to laboratory tests was measured by the pretask-to-task increase in variables. The high SBP variability 1 group showed a significantly higher reactivity of SBP and noradrenaline in the bicycle exercise test (70w). This suggests the possibility that SBP variability 1, can be predicted by increased reactivity to a mild limb exercise test. The high HR variability 1 group, and the high SBP variability 2 group showed significantly lower reactivity of stroke volume (SV) and cardiac output (CO) in the cold face test. Thus, parasympathetic responses such as trigeminal-brainstem-vagal pathway function or baroreflex sensitivity seemed to be reduced in these groups. The high DBP variability 2 group showed significantly lower DBP reactivity in the cold face test, and low noradrenaline reactivity in the mental arithmetic test, which indicated a reduced alpha-adrenergic response in this group. No other significant differences in reactivity to the laboratory mental stress tests were found between the variability 1 and variability 2 groups.

Topological analysis of quinoprotein glucose dehydrogenase in Escherichia coli and its ubiquinone-binding site

Topological structure of quinoprotein glucose dehydrogenase in the inner membrane of Escherichia coli was determined by constructing protein fusions with alkaline phosphatase or beta-galactosidase. Analysis of the fusions revealed that the dehydrogenase possesses five membrane-spanning segments, and the N-terminal and C-terminal portions resided at the cytoplasmic and periplasmic side of the membrane, respectively. These results agreed with the hydropathy profile based on its primary structure. The topological structure suggests that the predicted binding site of the prosthetic group pyrroloquinoline quinone is located at the periplasmic side and that the amino acid residues corresponding to those that were presumed to interact with ubiquinone in one subunit of mitochondrial NADH dehydrogenase also occur at the periplasmic side. When the purified glucose dehydrogenase and cytochrome o ubiquinol oxidase were reconstituted together with ubiquinone into liposomes, a membrane potential could be generated by the electron transfer at the site of the ubiquinol oxidase but not of the dehydrogenase. These results suggest that glucose dehydrogenase has a ubiquinone reacting site close to the periplasmic side of the membrane, and thus its electron transfer to ubiquinone appears to be incapable of forming a proton electrochemical gradient across the inner membrane of E. coli.

Different clinical features in monozygotic twins: a case of 7q--syndrome

We present male monozygotic twins who showed quite different clinical features. Blood chromosome analysis revealed 46,XY/46,XY,del(7) (q32-->qter) mosaicism in both twins. However, cultured skin fibroblasts from the twins showed different karyotypes. Twin 1, with a normal phenotype, had normal chromosomes and was 46,XY. Twin 2, on the other hand, had the characteristic manifestations of 7q- syndrome and chromosomes of 46,XY,del(7) (q32-->qter). DNA fingerprint analysis of their peripheral blood samples revealed the same pattern. However, DNA fingerprint patterns of cultured skin fibroblasts and buccal mucosal cells were different when a 7q terminal marker, probe g3, was used. These identical twins with discordant phenotypes can be explained by the occurrence of twinning and simultaneous erroneous mitosis. In addition, there might be a vascular communication which probably resulted in blood exchange and chromosomal mosaicism of the lymphocytes of the monozygotic twins.

Seroepidemiology status of Nepalese against hemolytic streptococcal infection in Katmandu

Immune status of apparently healthy Nepalese against hemolytic streptococci was studied by measuring antibodies to various streptococcal antigens such as streptolysin-O (SO), streptokinase (SK), deoxyribonuclease-B (DN-B) and streptococcal polysaccharide (SP). The normal range of anti-streptolysin-O (ASO), anti-streptokinase (ASK), anti-deoxyribonuclease-B (ADN-B) and anti-Streptococcus polysaccharide (ASP) was 60-480 (T.U.), 40-1024 (titer), 60-1280 (titer) and less than 2-128 (Unit), respectively. No difference was observed between the two sexes. ASO and ADN-B were measured by the neutralization method. Passive hemagglutination (PHA) was used to measure ASK and ASP. These values were 2-3 fold higher than those obtained on the Japanese subjects.

Similarity graphing and enzyme-reaction database: methods to detect sequence regions of importance for recognition of chemical structures

We developed a new method which searches sequence segments responsible for the recognition of a given chemical structure. These segments are detected as those locally conserved among a sequence to be analyzed (target sequence) and a set of sequences (reference sequences). Reference sequences are the sequences of functionally related proteins, ligands of which contain a common chemical substructure in their molecular structures. 'Similarity graphing' cuts target sequences into segments, aligns them with reference sequence pairwise, calculates the degree of similarity for each alignment, and shows graphically cumulative similarity values on target sequence. Any locally conserved regions, short or long in length and weak or strong in similarity, are detected at their optimal conditions by adjusting three parameters. The 'enzyme-reaction database' contains chemical structures and their related enzymes. When a chemical substructure is input into the database, sequences of the enzymes related to the input substructure are systematically searched from the NBRF sequence database and output as reference sequences. Examples of analysis using similarity graphing in combination with the enzyme-reaction database showed a great potentiality in the systematic analysis of the relationships between sequences and molecular recognitions for protein engineering.