Biomedical subjects

M Wada

Publications and source records attributed to M Wada.

At least 325 records · Page 18Linked to original sources

PubMed1997

Purification and some properties of cobalamin-dependent methionine synthase from rat liver.

Cobalamin-dependent methionine synthase was purified from rat liver. The enzyme activity was separated into two peaks upon Mono-Q column chromatography. Peaks I and II of the enzyme, eluted in this order, were purified 18,000- and 44,000-fold in overall yields of 0.7 and 1.8%, respectively. Peak II methionine synthase, the major fraction, was homogeneous as judged by SDS-polyacrylamide gel electrophoresis. The enzyme was a large monomeric protein with an apparent molecular weight of 143,000 Da. Interconversion of the enzyme between the two peaks was not observed during purification procedures. The enzyme required S-adenosylmethionine and a reducing system for activity. Apparent K(m) values of the peak II enzyme for 5-methyltetrahydrofolate and homocysteine were 75 and 1.7 microM, respectively.

5-Methyltetrahydrofolate-Homocysteine S-Methyltran↗

PubMed1997

[Serodiagnosis with trehalose-6,6'-dimycolate of pulmonary tuberculosis].

Enzyme-linked immunosorbent assay (ELISA) was used to examine serum antibody levels of mycobacterial antigen in 92 patients with active tuberculosis, 36 with cured tuberculosis, 45 with nontuberculous mycobacteriosis, and as 31 with other diseases. Glycolipid fraction containing mainly cord factor (trehalose-6,6'-mycolate) from Mycobacterium tuberculosis H37Rv were used as ELISA antigen. Overall positive rates of the ELISA tests in the patients with active pulmonary tuberculosis, those with nontuberculous mycobacteriosis, and those with other diseases were 67.4%, 75.6%, and 6.5%, respectively. Patients with tuberculosis and those with nontuberculous mycobacteriosis differed from the control group (p < 0.0001). Higher positive rates were correlated with bacterial loads (smear-positive vs smear-negative, p < 0.01) and with chest roenrgenographic findings (far advanced or other cavitary vs noncavitary, p < 0.01). Because 18 of 36 smear-negative patients (50%) had positive results, we believe that the ELISA test with this antigen can be useful for diagnosis of M. tuberculosis, especially in patients with smear-negative.

Antibodies, Bacterial↗

PubMed1997

Effect of vitamin B12-deficiency on testicular tissue in rats fed by pair-feeding.

The effect of vitamin B12 (B12)-deficiency on testicular tissue was investigated through morphological observations of the rats which had been fed on a B12-deficient soybean protein diet by pair-feeding for 100 days. Testicular B12 content was depressed distinctly by the deficiency. Testes weight and their relative weight (weight per 100 g body weight) as well, decreased significantly as compared with those of pair-feeding control rats. Although the decrease in the testicular B12 content due to B12-deficiency was compensated by the administration of cyanocobalamin (CN-B12), alleviation of the decrease in testes weight and relative testes weight was not observed under the condition of the short-term CN-B12 administration. Morphological observations of the testicular tissue in B12-deficient rats revealed atrophy of the seminiferous tubules and aplasia of sperms and spermatids, while testicular findings in both ad libitum-feeding control rats and pair-feeding control rats were normal. There was a tendency for the decrease in seminiferous tubules showing spermatogenesis to be alleviated by administration of CN-B12. The above results indicate that the morphological changes in the testicular tissue are ascribable to B12-deficiency.

Animals↗

PubMed1997

[A reversible posterior leukoencephalopathy syndrome in a patient with classical polyarteritis nodosa].

We report a case of a reversible posterior leukoencephalopathy syndrome (RPLS). A 57-year-old male had classical polyarteritis nodosa with mononeuritis multiplex, renal insufficiency, and a high titer of p-ANCA (MPO). He was normotensive. He was treated with high dose methylprednisolone and then with oral prednisolone and cyclophosphamide. Despite the treatment, his renal function rapidly deteriorated and hypertension progressed. He had two generalized seizures; at that time his blood pressure was 200/140 mmHg. CT scan revealed bilaterally symmetric hypodensities in the thalamus, the occipital white matter, and the brainstem. T2-weighted MRI showed increased signal intensities in the temporo-occipital white matter, the thalamus, the posterior limbs of the internal capsules, the external capsules, the midbrain, the pons, and the middle cerebellar peduncles. T1-weighted images showed hypointensities in these areas. Treatment with nifedipine improved his blood pressure; 5 days later he was only moderately disoriented. Follow-up CT demonstrated an ill-defined hypodense area only in the left parietal lobe. To our knowledge, there are only two reported cases of RPLS associated with systemic vasculitides. Interestingly, thalamic lesions are outstanding also in these cases. Under these circumstances, treatment of hypertension is of primary importance, and steroid therapy should not be withdrawn or reduced.

Brain Diseases↗

PubMed1997

[Progress in the treatment of multiple myeloma].

Melphalan and prednisolone (MP) have been the standard therapy for multiple myeloma for more than 25 years. Although they produce an objective response in 50-60% of patients, complete remission (CR) is rare and the median survival period is generally 24 to 30 months. Many combination chemotherapeutic agents have been used and resulted in approximately 70% objective response, but the median duration of survival has not significantly been improved. VAD regimen is effective for many patients with myeloma resistant to MP therapy. Furthermore, VAD-cyclosporin combination induces responses in approximately 40% of patients with VAD-resistant myeloma, with increased expression of the multi-drug resistant gene (MDR). Intravenous administration of high dose-melphalan also produces responses in approximately 30% of patients with myeloma resistant to VAD. Interferon-alpha therapy with an alkylating agent-glucocorticoid regimen, shows a higher response rate but similar survival time, compared with those obtained with the MP therapy alone. High-dose therapy with transplantation is promising. High-dose therapy combined with autologous bone marrow transplantation improves the response rate, event-free survival (EFS), and overall survival (OS) in patients with myeloma, demonstrated in the prospective, randomized trial by Attal et al. Total therapy by Barlogie et al. consisted of non-cross-resistant induction regimens, followed by a double autotransplantation (AT) procedure. Compared with the outcome of patients receiving standard therapy, dose intensification with double AT produces not only higher CR rates but also significantly extends EFS and OS in previously untreated patients with myeloma. The reduced mortality rate associated with transplantation, and development of new chemotherapeutic agents will lead to future improvements of the therapy for multiple myeloma.

Antineoplastic Combined Chemotherapy Protocols↗

PubMed1997

Developmental changes in functional EEG asymmetry: a multivariate autoregressive modeling approach.

To investigate the functional asymmetry of the electroencephalogram (EEG) in the developing brain, we analyzed quantitatively the different components of simulated EEG (SEEG) in a model before and after cutting off the intercerebral interaction. Original EEG (OEEG) recordings were obtained from 374 normal children aged 3-12 years. The SEEGs were computed from the OEEG after applying 'ARdock', a new multivariate autoregressive (AR) modeling method. Subsequently, the univariate AR and component analysis was applied on OEEG and SEEG. The F value was computed from Mahalanobis' distance between both AR coefficients of component activities for age, EEG derivation and frequency band. Our analysis showed developmental lateralities in the alpha band at the frontal pole in 5 and 12 year old children, and at the central region in 8 and 11 year old children. Our results suggest that the intercerebral interactions develop at approximately 5 years of age at the left frontal pole during the period of maturation of alpha band activity and after 8 years of age when it replaced theta band activity. The present method of analysis may have a wide clinical application in the analysis of normal and abnormal EEGs.

Brain↗

PubMed1997

[Pyrazinamide-containing initial intensive short course chemotherapy of pulmonary tuberculosis].

Six-month short course regimen had been accepted all over the world since early 1980s. In Japan this short course regimen had not been accepted as a standard regimen for treatment of pulmonary tuberculosis until April 1996. The reason why this was not accepted is resumably due to hepatotoxicity of pyrazinamide. The situation around tuberculosis were changing in Japan especially in urban areas. Incidence of tuberculosis in younger generations is higher in urban areas than in rural areas. More effective and shorter course regimen were needed. Efficacy of pyrazinamide were briefly described first, then results of six-month regimen with pyrazinamide in Fukujuji Hospital since 1991 January were discussed. Pyrazinamide can kill tubercle bacilli in acidic environment. It works bacericidally during the early treatment phase. It can kill not only replicating bacilli but also semidormant ones. The results of many six-month regimens showed that only pyrazinamide containing regimens were acceptable for standard regimen in pulmonary tuberculosis with less than a few percent of relapse. Newly accepted standard chemotherapy included 2HRZ with or without S or E/4HRE, 6HRS or E/3HR, and 6HR. Among 429 tuberculosis patients treated at Fukujuji Hospital with pyrazinamide-containing regimens, the negative conversion rate after two months of chemotherapy was 95 percent and similar to those of Western, African and Asian tuberculosis trials. Six of 290 evaluable cases have relapsed. (relapse rate; 2%) Noticeably all relapsed cases were complicated with diabetes mellitus. The higher percent of patients, 8.2 had elevated serum transaminase levels 5 times of upper limit of normal level or more compared with that of patients without pyrazinamide, 6.6 percents, but this difference is not statistically significant. One patient whose pretreatment liver function was abnormal with unknown origin died from hetatoxicity of anti-tuberculous drugs. The risk factors of hepatotoxicity included HCV carrier, elderly more than 80 years old, but HB carrier, alcohol drinking and hepatic diseases were not risk factors. Less patients, 5.6% defaulted from regimen compared with that with 9-month regimen without pyrazinamide (8.6%), but this difference is not statistically significant. The efficacy of the regimen was 90.3% higher than that of 9-month regimen, 86.0% In summary, six-month regimen containing pyrazinamide is highly effective. The incidence and severity of hepatotoxicity must be further studied in Japan.

Aged↗

PubMed1997

[An observation on tuberculosis associated with HIV infection in Japan].

OBJECTIVE: To observe the reported cases of tuberculosis (TB) with HIV infection in Japan, in terms of their main clinical features and related factors. METHODS: A voluntary reporting network has been organized by the authors who are specialists of TB or respiratory medicine in tuberculosis institutions located roughly all over the country. The members have been encouraged to report not only their own cases but cases seen by their friends or in other institutions. RESULTS: By the end of 1996, a total of 71 cases have been reported of which 59 were TB and 12 NTM cases. Nationality of the cases were; Japan 48, Other Asian countries 16, Others 7. All of the NTM cases were Japanese. 30% of the cases were aged less than 30 years, 24% were thirties, 24% forties, 17% fifties and 6% were those aged 60 years or older. The cases were clearly younger than the TB cases in the national TB registry, and older than HIV-infected persons as known from the HIV surveillance system. 97% of the TB cases were bacteriologically confirmed cases. Eight of NTM cases were positive for MAC, others for M.kansasii. 42% of the cases had extra-pulmonary disease, including disseminated infections seen among 19%. Of TB cases 25% were excreting bacilli resistant to any of the anti-TB drugs which was higher than in the case of general TB population (10-15%). 11% of TB cases had past history of TB treatment. The cases had severe immunological impairment, 79% of the cases having CD4+ cell count less than 100. The route of HIV infection were; 51% heterosexual, 13% homosexual, 13% through blood preparations, etc. DISCUSSION: Although there may be many cases not included in this observation, it is considered to well reflect the real situation of the problem of Japan. More attention should be paid to HIV infection of the patients in the clinical practice of TB in Japan.

AIDS-Related Opportunistic Infections↗

PubMed1997

[Pharmacokinetic and clinical evaluation of cefozopran in premature and newborn patients].

Cefozopran (SCE-2787, CZOP), which is already on the market with a variety of approved indications in infectious diseases for adult patients, was administered to premature and newborn patients to evaluate the pharmacokinetics and the clinical efficacy. 1. Pharmacokinetics CZOP was intravenously administered at doses of 10.0 mg/kg, 21.4 mg/kg and 40.0 mg/kg to premature and newborn patients, and the blood concentrations and urinary excretion rate were examined. The blood CZOP concentrations were 31.7 and 65.5 micrograms/ml at 30 minutes after administration of 10.0 mg/kg and 40.0 mg/kg, respectively. The elimination half life was 1.78 hours and 2.31 hours, and the urinary recovery was 110.7% and 53.7% within 6 hours after administration, respectively. In the patient given 21.4 mg/kg, the blood CZOP concentration was 36.4 mg/kg at 1 an hour after administration and the elimination half life was 3.97 hours. The urinary recovery was 29.6% within 5 hours after administration. 2. Clinical results The clinical efficacy was evaluated in 19 patients and judged "good" or better in 13 of them with the efficacy rate or 68.4%. The bacteriological response was evaluated in 10 patients from whom Gram-positive cocci of S. aureus (6 strains), S. pneumoniae (1 strain) and E. faecalis (1 strain) and Gram-negative bacilli of H. influenzae (2 strains) and E. coli (2 strains) were isolated as possible causative organisms. With exception of 1 strain each of S aureus and H influenzae, which were not tested after the treatment with CZOP, all of these strains were found to be eradicated. 3. Adverse drug reactions (ADRs) of signs and symptoms and abnormal alterations of laboratory test values. Safety evaluation was made in 24 patients. ADRs of signs and symptoms were recognized in none of them. As abnormal alterations of laboratory test values, increased eosinophils in 3 patients, elevated GOT in one and elevated GPT in one were recognized. These results indicate that CZOP is a drug useful for treatment of infections in premature and newborn patients.

Bacterial Infections↗

PubMed1997

[Clinical study on azithromycin in 10% fine granules and 100mg capsules in the field of pediatrics].

Azithromycin (AZM), a new oral macrolide antibiotic, in 10% fine granules or 100 mg capsules was given to pediatric patients to treat various infections. The following results were obtained in our studies of AZM for its antibacterial activities against clinical isolates, its pharmacokinetics, its efficacy, and its safety. 1. MICs of AZM, erythromycin (EM) and clarithromycin (CAM) were determined against a total of 57 strains all at 10(6) cfu/ml. Among Gram-positive cocci, MICs of AZM ranged from 0.78 to > 100 micrograms/ml against Staphylococcus aureus (20 strains), from 0.05 to 0.1 microgram/ml against Streptococcus pyogenes (11 strains), and from 0.0125 to 3.13 micrograms/ml against Streptococcus pneumoniae (10 strains). These MICs were similar to those of the other macrolides. Among Gram-negative bacilli, MICs of AZM were 0.05 micrograms/ml against Moraxella subgenus Branhamella catarrhalis (1 strain), from 0.78 to 3.13 micrograms/ml against Haemophilus influenzae (9 strains), 0.78 micrograms/ml against Haemophilus parainfluenzae (1 strain) and 6.25 micrograms/ml against salmonella sp. (1 strain). These values were similar to or lower than those of the other macrolides. Against Mycoplasma pneumoniae, MICs of AZM were < or = 0.0008 micrograms/ml in three strains. One strain of M. pneumoniae showed tolerance to AZM at MIC 25 micrograms/ml. The other agents exhibited higher MIC than AZM against this organism. 2. Plasma samples were collected from five patients receiving fine granules and four patients receiving capsules for drug level determination. The patients received AZM at 10.0 approximately 16.3 mg/kg body weight once daily for 3 days. Drug concentrations in plasma at two hours after Day 3 dosing were in a range between 0.02 and 0.19 micrograms/ml for fine granules and were in a range between 0.11 and 0.42 micrograms/ml for capsules. 3. Urine samples were collected from four patients receiving fine granules and four patients receiving capsules. Drug levels were determined to be 3 micrograms/ml at post-treatment 48 hours for fine granules and post-treatment 72 hours for capsules. Urinary excretion rates of AZM in three patients on capsules lied in a range between 4.69 and 10.17%. 4. Effectiveness of AZM in fine granules was evaluated in 128 patients having a total of 19 different infections. AZM was rated "excellent" in 51 patients, "good" in 63, "fair" in 8, "poor" in 6, resulting in an efficacy rate of 89.1%. Effectiveness of AZM in capsular form was evaluated in 23 patients with five different infections. AZM was found "excellent" in 13 patients and "good" in 10, resulting in an efficacy rate of 100%. 5. AZM in fine granules eradicated 45 strains of 54 in 8 different bacteria. AZM in capsules eradicated 9 strains of 10 strains in 6 different bacteria. 6. As for adverse reactions, one patient complained of eruption, one vomiting, one loose stool, five diarrhea, when administered with fine granular form of AZM. One patient on AZM capsules experienced urticaria and vomiting. 7. As for abnormal laboratory changes, three patients were found with decreased WBC, seven with increased eosinophil, two with increased GOT and GPT, one with increased GPT. They were all on fine granular form of AZM. As far as abnormalities found in patients administered with AZM in capsular form, two showed decreased WBC, one decreased WBC along with increased eosinophil, and three increased eosinophil.

Adolescent↗

PubMed1996

Enhanced coexpression of thioredoxin and high mobility group protein 1 genes in human hepatocellular carcinoma and the possible association with decreased sensitivity to cisplatin.

Thioredoxin (TRX), a disulfide-reducing intracellular protein, functions as a cellular defense mechanism against oxidative stress. In this study, we asked whether expression of TRX, glutathione-thiol transferase pi, and high mobility group protein 1 (HMG-1) genes is enhanced in human hepatocellular carcinoma and whether expression of these genes is associated with sensitivity to cisplatin. Both TRX and HMG-1 were co-overexpressed in almost all cancerous lesions in comparison to normal tissue in surgically resected hepatocellular carcinomas of 20 patients. Tumor sensitivity to cisplatin [cis-diamminedichloroplatinum (II)], but not to mitomycin C or doxorubicin, correlated with mRNA levels of TRX in cancer tissue. TRX and HMG-1 may be useful tumor markers, and TRX might be also a useful marker for sensitivity to cisplatin in human hepatocellular carcinomas.

Adult↗

PubMed1996

Increased expression of T-plastin gene in cisplatin-resistant human cancer cells: identification by mRNA differential display.

The cellular resistance to the potent anticancer agent cis-diamminedichloroplatinum(II) (cisplatin) is thought to be mediated by multiple mechanisms. The technique of differential display of mRNAs was applied to various cisplatin-resistant cell lines and the corresponding parental sensitive human bladder, prostatic, and head and neck cancer cells in order to identify genes that underlie cisplatin resistance. Twenty-four clones were confirmed by Northern blot analysis to be expressed differentially between resistant and the corresponding sensitive cells. Partial DNA sequences of the eight clones that showed a threefold or greater increase in expression in either the resistant cells (seven clones) or sensitive cells (one clone) revealed that two were derived from the T-plastin gene and one from the tissue factor gene. The abundance of T-plastin mRNA in cisplatin-resistant T24/DDP10 cell was approximately 12 times that in the parental T24 cells. Transfection of T24/DDP10 cells with a vector encoding full-length T-plastin antisense RNA demonstrated that reduced T-plastin expression was associated with increased sensitivity to cisplatin. These results are consistent with the hypothesis that several mechanisms participate cooperatively in the acquisition of cisplatin resistance in human cancer.

Antineoplastic Agents↗

PubMed1996

A human canalicular multispecific organic anion transporter (cMOAT) gene is overexpressed in cisplatin-resistant human cancer cell lines with decreased drug accumulation.

By targeting the ATP binding conserved domain in three ATP binding cassette superfamily proteins (P-glycoprotein, multidrug resistance protein, and cystic fibrosis transmembrane regulator), we isolated the cDNA of a new ATP binding cassette superfamily that was specifically enhanced in a cisplatin-resistant human head and neck cancer KB cell line. A human clone homologous to rat canalicular multispecific organic anion transporter (cMOAT) was found and designated human cMOAT. Fluorescence in situ hybridization demonstrated the chromosomal locus of the gene on chromosome 10q24. The human cMOAT cDNA hybridized a 6.5-kb mRNA that was expressed 4- to 6-fold higher by three cisplatin-resistant cell lines derived from various human tumors exhibiting decreased drug accumulation. Human cMOAT may function as a cellular cisplatin transporter.

Adenosine Triphosphate↗

PubMed1996

Potent inhibitors of secretory phospholipase A2: synthesis and inhibitory activities of indolizine and indene derivatives.

Phospholipase A2 is an enzyme which hydrolyzes the sn-2 position of certain cellular phospholipids. The liberated lysophospholipid and arachidonic acid are precursors in the biosynthesis of various biologically active products. As human nonpancreatic sPLA2 is present in high levels in the blood of patients in several pathological conditions, the potent sPLA2 inhibitors have been suggested to be useful drugs. Here we describe the synthesis, structure-activity relationship, and inhibitory activities of indolizine and indene derivatives. 1-(Carbamoylmethyl)indolizine derivatives and 1-oxamoylindolizine derivatives exhibited very potent inhibitory activity. The former was unstable to air oxidation, but the latter exhibited an improvement both in stability and in potency. Some compounds approached the stoichiometric limit of the chromogenic assay.

Alkylation↗

PubMed1996

Structural and functional analysis of the human Y-box binding protein (YB-1) gene promoter.

We have isolated three overlapping genomic clones containing the 5'portion of the human YB-1 gene. These clones span approximately 25 kb of contiguous DNA containing 10 kb of 5' flanking sequence and 15 kb of the gene. The nucleotide sequence of the first exon and of 2000 upstream base pairs (bp) was determined. The first axon is unusually large and contains a 166 bp coding sequence and a 331 bp untranslated region. CpG sequences cover the 5'-end of the YB-1 gene including its first axon and intron as well as the upstream regions. The GC content around the first exon is approximately 70% and a CpG-free region was located in the untranslated sequence. The segment preceding the major transcription initiation site does not contain a TATA box, CCAAT box and the binding sequence for known transcription factors. A transient expression assay using the chloramphenicol acetyltransferase (CAT) gene showed that the sequence from +24 to +281 was critical for CAT expression. Fluorescence in situ hybridization demonstrated the chromosomal locus of YB-1 gene on chromosome 1p34. Polymerase chain reaction analysis on other genomic phage DNAs showed that several clones were derived from pseudogenes.

Base Composition↗

PubMed1996

Drug-induced down-regulation of topoisomerase I in human epidermoid cancer cells resistant to saintopin and camptothecins.

The anticancer agent saintopin induces DNA cleavage mediated by both topoisomerase (topo) I and topo II in vitro through stabilization of the reversible enzyme-DNA cleavable complex. We established saintopin-resistant cell lines (KB/STP-1 and KB/STP-2) from human epidermoid cancer KB cells by stepwise exposure to increasing doses of the drug. KB/STP-1 and KB/STP-2 cells showed 12- and 44-fold increases, respectively, in resistance to saintopin relative to that of KB cells. Both saintopin-resistant cell lines showed only small reductions in sensitivity to the topo II inhibitor etoposide but developed marked cross-resistance to the topo I-targeting camptothecin derivative CPT-11 [(4s)-4,11-diethyl-4-hydroxy-9-[(4-piperidinopiperidino)carbony loxy] dione hydrochloride trihydrate] and its active form, SN-38 (7-ethyl-10-hydroxycamptothecin). In contrast, both KB/STP-1 and KB/STP-2 cells showed increased collateral sensitivity to cisplatin, a nitrosourea derivative, mitomycin C, and UV light. The protein concentration, activity, and mRNA abundance of both topo I and topo II were similar in KB/STP-1, KB/STP-2, and the parental KB cells. There were no significant changes in the drug-stabilized topo-DNA cleavable complex formation in KB and KB/STP-2 cells. Two point mutations were detected in topo I cDNA from KB/STP-2 cells, but these were also present in KB cells. Topo I mRNA abundance decreased markedly immediately after exposure of KB/STP-2 cells to saintopin; no such effects were apparent in KB cells. In contrast, topo II mRNA was not markedly affected by saintopin in either KB or KB/STP-2 cells. Treatment with CPT-11 or SN-38 also induced a markedly greater and more persistent reduction in topo I mRNA abundance in KB/STP-2 cells than in KB cells. Etoposide had no marked effect on topo I mRNA abundance in either KB/STP-2 or KB cells. Topo I mRNA was highly unstable in KB/STP-2 cells in comparison to KB cells when incubated with saintopin. This novel regulation of topo I mRNA by topo I-targeting agents could be associated with acquirement of drug resistance to saintopin or SN-38/CPT-11 in KB/STP-2 cells.

Antibiotics, Antineoplastic↗

PubMed1996

Unique telomeric expression site of major-surface-glycoprotein genes of Pneumocystis carinii.

Major cell surface glycoproteins (MSG) of Pneumocystis carinii play a crucial role in the host-parasite interactions involved in P. carinii pneumonia in AIDS patients. Genes encoding MSGs are repeated, highly polymorphic, and distributed among all of the 14-15 chromosomes. Here we show, by BAL-31 exonuclease cleavage and DNA cloning experiments, that the unique expression site (previously termed UCS) of MSG genes located in the 500-kb chromosome is telomeric. The 11-kb genomic UCS fragment isolated and sequenced in this study contained one MSG coding sequence (termed msg105), subtelomeric repetitive sequences and telomere-specific tandem repeats of TTAGGG oriented 5' to 3' towards the DNA end. Despite the N-terminal polymorphism, the C-terminal one-third sequence of MSG105 was identical to one of the known MSG-cDNAs, suggesting homologous recombination within the MSG coding sequences. These features closely resemble the Variant Surface Glycoprotein system of the protozoan parasite Trypanosoma brucei, suggesting that the genetic heterogeneity of MSGs is generated by recombination between the UCS expression site and multiple MSG genes by means of reciprocal exchange or gene conversion.

Amino Acid Sequence↗

PubMed1996

Sensitive flow-injection method with peroxyoxalate chemiluminescence detection combined with preparative high-performance liquid chromatography for determination of choline-containing phospholipids in human serum.

A sensitive and rapid flow-injection analysis (FIA) of total choline-containing phospholipids (PLs) and a selective FIA method for the class assay of choline-containing PLs combined with preparative HPLC were described. The FIA method is based on peroxyoxalate chemiluminescence (PO-CL) detection of hydrogen peroxide enzymatically formed from choline-containing PL. The linear standard curves were obtained up to 1 nmol/20-microliters injection (r > 0.999) with the detection limits of 1.3-1.6 pmol at a signal-to-noise ratio of 2. The total amounts of choline-containing PLs in human serum were ranged from 1.63 to 3.19 mg/ml. The HPLC separation of choline-containing PLs was achieved with an aminopropyl-modified silica gel column using a mixture of acetonitrile-methanol-10 mM ammonium phosphate buffer pH 5.8 as eluent. The eluate corresponding to each choline-containing PL was collected, evaporated, dissolved in 0.1% Triton X-100 aqueous solution, and then injected into FIA system. The FIA method combined with preparative HPLC was applied to the assay of human serum.

Choline↗