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Biomedical subjects

N Okamoto

Publications and source records attributed to N Okamoto.

At least 217 records · Page 12Linked to original sources
PubMed1993

Decreased blood coagulation activities in carbohydrate-deficient glycoprotein syndrome.

The carbohydrate-deficient glycoprotein (CDG) syndromes are a newly recognized group of inherited metabolic diseases. We report a Japanese brother and sister with a CDG syndrome. Both patients showed decreased activities of blood coagulation Factor XI and of the coagulation inhibitor protein C. In one of them there was also a somewhat decreased activity of Factor IX and of antithrombin III. Isoelectric focusing of antithrombin III revealed a decrease of negatively charged fractions and an increase of more cathodal bands. Furthermore, there was a discrepancy between activity and antigen level of Factor VIII and protein C. The patients had an incidental deficiency of factor XII. This is the first detailed report on blood coagulation systems in the CDG syndromes. These blood coagulation abnormalities may explain at least in part the thrombotic or haemorrhagic complications of the CDG syndromes.

Antithrombin III↗
PubMed1993

Colorimetric detection for PCR amplified HIV-1 DNA using magnetic beads.

A rapid and nonradioactive detection method for polymerase chain reaction (PCR) amplified HIV-1 DNA was developed using a colorimetric detection system. Hybridization between biotin-labeled amplified targets and digoxigenin-capture probes occurs in solution followed by efficient and rapid capture onto streptavidin-magnetic beads. The presence of the digoxigenin-capture probe hybridized with biotin-labeled targets is then detected by antidigoxigenin-alkaline phosphatase conjugates using a colorimetric substrate. This approach is highly sensitive and can detect less than 10 HIV targets prior to PCR in approximately 50 min.

Bacterial Proteins↗
PubMed1993

Poly A-linked colorimetric microtiter plate assay for HIV reverse transcriptase.

An assay for detection of the reverse transcriptase (RT) of the human immunodeficiency virus (HIV) was developed using poly A linked to microtiter plate with colorimetric detection of incorporated biotin deoxyuridine triphosphate (biotin-dUTP). During the RT reaction, biotin-dUTP was incorporated into oligodeoxythymidylic acid (oligo-dT) which had been hybridized with poly A. At the detection step, horseradish peroxidase conjugated streptavidin was added, followed by the reaction of a colorimetric substrate for this enzyme. This method was contrasted with the two standard isotopic RT assays. There was excellent correlation between the colorimetric RT assay and each of two isotopic RT assays for both detection and quantification of avian myoblastosis virus reverse transcriptase (AMV-RT) and of HIV RT in human lymphocytes infected in vitro with HIV-1. The total assay required for performing the colorimetric assay, including the RT reaction, was 40 min.

Biotin↗
PubMed1993

Importance of successive prolines in the carboxy-terminal region of P450 2C2 and P450 2C14 for the hydroxylase activities.

Proline-480 and proline-481 are highly conserved in the P450 2 family. When these successive prolines of P450 2C2 were replaced by Ala-Thr, its activities of laurate (omega-1)-hydroxylation and benzphetamine N-demethylation were lost. On the other hand, the mutated P450 which retained one of the proline residues was 60-100% active in the (omega-1)-hydroxylation and 100-120% active in the N-demethylation. Pro-Pro (480, 481) to Ala-Thr mutated P450 2C14 was also inactive in testosterone 16 alpha-hydroxylation and benzphetamine N-demethylation, the activities of the wild-type P450 2C14. In the carboxyterminal region of the P450 2C subfamily, the sequence of P450 2C2 from residues 469-473 is noticeably different from those of the other members of this subfamily. The Ser-473 to Val mutation of P450 2C2 caused a decrease in the (omega-1)-hydroxylase activity to one-fifth but the N-demethylase activity was not much affected. When the sequence of P450 2C2 from residues 469-473 was replaced by that of P450 2C14 (mutation at four residues), the 16 alpha-hydroxylase and N-demethylase activities were increased by seven- and three-fold, respectively, and the (omega-1)-hydroxylase activity was decreased to one-third. The mutated P450 2C2, in which the carboxy-terminal four residue sequence or the proline cluster adjacent to the amino-terminal membrane-anchor signal sequences was deleted, was not accumulated in yeast cells transformed with plasmids directing the synthesis of such P450s.(ABSTRACT TRUNCATED AT 250 WORDS)

Amino Acid Sequence↗
PubMed1993

Detection of human immunodeficiency virus (HIV) by colorimetric assay for reverse transcriptase activity on magnetic beads.

A colorimetric assay for detection of reverse transcriptase (RT) of the human immunodeficiency virus (HIV) was developed using oligodeoxythymidylic acid (oligo-dT)-linked magnetic beads and digoxigenin-deoxyuridine triphosphate (dig-dUTP). During the RT reaction, dig-dUTP was incorporated into oligo-dT which had been hybridized to polyadenylic acid [poly (A)]. At the detection step, an alkaline phosphatase-conjugated antibody to digoxigenin was added, followed by the addition of a colorimetric substrate for this enzyme. This method showed excellent correlation with the isotopic RT assay, which used tritiated thymidine triphosphate ([3H]dTTP), for detection of purified avian-myeloblastosis-virus RT (AMV-RT). This assay also demonstrated close correlation with the isotopic RT assay using human peripheral-blood lymphocytes infected in vitro with HIV. This colorimetric RT assay offers important advantages over the conventional radioactive RT assays with respect to its simplicity, safety and cost. The total assay time, including the RT reaction step, was less than 1 h, and therefore provides a reliable rapid assay for detection and quantification of HIV.

Avian Myeloblastosis Virus↗
PubMed1993

[A case of prostatic carcinoma presenting as abdominal mass].

A 69-year-old man was admitted to the hospital on August 7, 1991 because of a lower abdominal mass. On physical examination, firm, rough-surfaced, unmovable masses of over fist size were palpable in the lower abdomen along with some small masses in the bilateral inguinal regions. On rectal examination the prostate was rough, hard and stony and larger than a chicken's egg in size. The serum prostatic acid phosphatase and prostatic specific antigen levels were elevated. A computerized tomography scan disclosed a large mass in the pelvis. Both a needle biopsy of the prostate and resection of an inguinal mass revealed moderately differentiated adenocarcinoma. Bone scintigram disclosed multiple metastases. Treatment with diethylstilbestrol diphosphate, etoposide, peplomycin and ifosfamide was effective, resulting in regressed intrapelvic masses and decreased serum prostatic acid phosphatase and prostatic specific antigen levels close to the normal limits. In November 1991, the patient was discharged and was surviving with the tumor as of August 1992.

Abdominal Neoplasms↗
PubMed1993

[Potential laser hazards to bystanders during photocoagulation].

The authors measured reflected laser beams delivered by slit-lamp photocoagulator and binocular indirect ophthalmoscope laser delivery systems, to evaluate potential hazards to the eyes of bystanders. 514 nm laser beams were used; reflected laser beams were measured by a light power meter (Advantest: TQ8210). Reflected lasers were found to be hazardous at 1 meter from whitish tile when a 0.75 Watt laser beam was delivered by the binocular ophthalmoscope laser system, as in an operating room. At 1 meter from a wall in a photo-coagulating room for out-patients, the reflected laser beam was found to be well below hazardous levels. Reflections at 40 cm from a non-laser-coated Goldmann 3-mirror contact lens were 2.66 mW/cm2, which exceeds the exposure limits, when 0.3 W laser was delivered by the slit-lamp photocoagulator. This decreased 85-90% when the laser was reflected from a laser-coated lens. From the point of view of safety, it is recommended that laser surgeons replace non-laser-coated lenses with laser-coated ones.

Eye↗
PubMed1992

Structure of serum transferrin in carbohydrate-deficient glycoprotein syndrome.

The structure of the defective transferrin in carbohydrate-deficient glycoprotein syndrome was characterized. Structurally abnormal sugar chains were not found in reversed phase chromatograms of pyridylaminated derivatives from the transferrin of two patients in different families. Electrospray ionization mass spectrometry of the whole transferrin molecules revealed an abnormal species that was smaller than normal tetrasialotransferrin by 2,200 daltons, just the size of the disialylated biantennary sugar chain. These data indicated that the disialotransferrin specifically found in this syndrome is missing either of two N-linked sugar chains, suggesting a metabolic error in the early steps of protein glycosylation.

Carbohydrate Metabolism, Inborn Errors↗
PubMed1992

Nephroblastomas in the Japanese eel, Anguilla japonica Temminck and Schlegel.

Nephroblastomas were observed in 50 Japanese eel reared at a farm for 5 to 9 months from 1989 after collection in the wild. The tumors, arising from the trunk kidney near the anus, were noted externally as abdominal swellings and varied in size from 30 to 75 mm in maximum diameter. Most were elastic, solid, and well encapsulated. Histologically, the nephroblastomas were composed of combinations of three main tissue elements. Spindle- or oval-shaped cells resembling human blastema cells were observed in most tumors to some larger or smaller degree. Although variation was evident from tumor to tumor, and even within the same tumor, the most common histological type was epithelial with formation of alveolar nests, the cells sometimes being arranged in tubular structures simulating normal renal tubules. A muscle tissue element with distinct cross-striations was also observed. Liver metastases were found in one case. Histological examination of apparently normal kidneys from 100 eels revealed one early-stage nephroblastoma. The cause of these tumors is unclear, although they have been discovered with increasing incidence after the spread of indoor eel culture with raised water temperatures (26-27 degrees C) in Japan. Environmental factor(s) associated with the new aquaculture method may thus play a role in their genesis.

Anguilla↗
PubMed1992

Activation of human natural killer cells by the protein-bound polysaccharide PSK independently of interferon and interleukin 2.

The protein-bound polysaccharide PSK was tested for the ability to activate human natural killer (NK) cells. When blood lymphocytes and purified CD3-CD16+ large granular lymphocytes (LGL) were treated in vitro overnight with PSK, they demonstrated enhanced NK cell activity against K562. The PSK-activated killer cells also lysed NK-resistant targets and freshly isolated autologous and allogeneic tumor cells. The PSK effect was observed with concentrations that could be obtained in the blood of cancer patients receiving oral administration of PSK. PSK-induced enhancement of NK activity was not abrogated by monoclonal antibodies (mAb) that neutralized interferon (IFN) alpha, IFN gamma, or interleukin-2 (IL-2). In addition, mAb reactive with p55 (alpha chain) or p75 (beta chain) glycoproteins of IL-2 receptors had no effects on PSK-enhanced NK activity even when used simultaneously. These results indicate that the PSK could activate human NK cells independently of IFN and IL-2/IL-2R systems.

Adenocarcinoma↗
PubMed1992

Search for MHC-associated genes in human: five new genes centromeric to HLA-DP with yet unknown functions.

Taking advantage of five mouse genomic or cDNA probes [KE5(probe 14), KE4 (probe 11), KE3 (probe 7), KE2 (probe 5), and SET] mapped on the H-2K region in mouse, we have identified and localized homologues of these five genes in the human major histocompatibility complex region (HKE5, HKE4, HKE3, HKE2, and HSET, respectively). Cosmid cloning and pulsed field gel electrophoresis analyses indicated that a human homologous gene, HKE5, is located 10 kilobases (kb) centromeric of the alpha 2 (XI) collagen (COL11A2) gene followed by HKE4. HKE3, closely linked to HKE2, is located 170 kb centromeric of HKE4. Furthermore, HSET is located 50 kb centromeric of HKE2. This gene organization outside the DP subregion is completely identical to that of the mouse H-2K region centromeric of I-Pb3, a mouse homologue of the DPB gene, except the lack of genes corresponding to the H-2K and -K2 genes in human.

Blotting, Southern↗
PubMed1992

Development of hepatocellular carcinoma associated with increases in DNA synthesis in the surrounding cirrhosis.

The relationship between DNA synthesis activity in hepatocytes from cirrhotic tissue and development of hepatocellular carcinoma was studied in 33 posthepatitic patients with Child's grade A cirrhosis. DNA synthesis activity was measured by a bromodeoxyuridine (a thymidine analogue) labeling index, using the bromodeoxyuridine-antibromodeoxyuridine in vitro method, and the patients were followed up prospectively with frequent liver ultrasonography for 2 years. During the 2-year follow-up, 11 of the 33 cirrhotic patients developed hepatocellular carcinoma; they included 8 of the 15 patients (53%) in the high labeling index (greater than 1.5%) group compared with only 3 of the 18 patients (17%) in the low labeling index (less than 1.5) group (P less than 0.05). Five of the latter 18 subsequently had increased synthesis activity. Of these 20 patients who showed high synthesis activities either initially or subsequently, 10 (50%) developed hepatocellular carcinoma, in contrast to 1 of 13 (8%) with persistently low activities (P less than 0.05). Thus, hepatocellular carcinoma seems to develop or may become detectable when DNA synthesis in the background cirrhosis is increasing or remains high.

Adult↗
PubMed1992

Chemiluminescent microtiter method for detecting PCR amplified HIV-1 DNA.

A rapid and sensitive method for detecting HIV-1 DNA sequences amplified by polymerase chain reaction (PCR) is described. The method uses solution phase hybridization for rapid and efficient annealing between digoxigenin-labeled targets and biotinylated capture probes. Hybrids containing biotin are captured onto streptavidin coated microwells and all other PCR components are washed away, including spurious amplification products. The presence of the digoxigenin-labeled amplified HIV target is then detected by anti-digoxigenin-alkaline phosphatase conjugates using the chemiluminescent substrate PPD. This approach maintains high specificity by nucleic acid dependent capture, and high sensitivity by efficient solution hybridization. The method is rapid (2 hours), and capable of detecting 10 HIV targets.

Alkaline Phosphatase↗
PubMed1992

Epidemiology of childhood diabetes in Osaka District, Japan, using the documents from the medical benefits system specific for childhood diabetes.

For an epidemiological study of childhood diabetes, application forms for medical benefits filed in Osaka Prefecture were collected and analyzed. A total of 465 patients with childhood diabetes under 18 yr of age were identified during the period between 1978 and 1988; 371 (175 boys and 196 girls) of them were classified as insulin-dependent diabetes mellitus (IDDM), and the others were either non-insulin-dependent diabetes mellitus (NIDDM) or an unidentified type of diabetes. The mean annual incidence of IDDM was 1.68 for boys and 2.00 for girls per 100,000 population, the rate being slightly higher for girls. The rates increased among older children, with a peak in the 10-14-yr age group. The prevalence estimated on the basis of the cumulative incidence in 1988 was 1.29 for boys and 1.60 for girls per 10,000 population, indicating a marked increasing trend with age. A significant seasonal variation was observed in the months of onset for IDDM, with higher rates during the winter. The mean birth weights of the male and female patients with IDDM were slightly lower than the national means. Use of official documents obtained from the medical benefits system was found to be an effective method for identification of cases of IDDM in the community, although further information is required for more accurate confirmation of such cases.

Adolescent↗
PubMed1992

Expression of aminopeptidase N and neutral endopeptidase on the endometrial stromal cells in endometriosis and adenomyosis.

Indirect immunofluorescence staining revealed that endometrial stromal cells (ESC) in the ectopic endometrium of patients with endometriosis or adenomyosis expressed aminopeptidase N/cluster of differentiation (CD) 13 antigen and neutral endopeptidase/CD10 antigen, both of which are expressed on ESC in the normal endometrium throughout the menstrual cycle. Thus, ESC in the ectopic endometrium resembled ESC in the normal endometrium not only morphologically but also antigenically. Both peptidase antigens may be useful markers for the histological diagnosis of endometriosis and adenomyosis.

Adult↗
PubMed1992

Human endometrial stromal cells and decidual cells express cluster of differentiation (CD) 13 antigen/aminopeptidase N and CD10 antigen/neutral endopeptidase.

With specific monoclonal antibodies, we found that human endometrial stromal cells and decidual cells express two function-related surface antigens. Indirect immunofluorescence staining revealed that both endometrial stromal cells and decidual cells during the first trimester of pregnancy expressed cluster of differentiation (CD) 13 antigen and CD10 antigen, which are identical to aminopeptidase N and neutral endopeptidase, respectively. By flow cytometric analysis, CD13 antigen was detected on 82-93% of the examined cells, and CD10 antigen was detected on 75-93% of the examined cells in endometrial stromal cell-enriched preparations. Furthermore, peptidase activity was detected in these cell preparations by an assay based on the hydrolysis of alanine-p-nitroanilide into p-nitroaniline and alanine.

Adult↗
PubMed1992

Pulmonary mucormycosis with fatal massive hemoptysis.

A case of pulmonary mucormycosis in a 57-year-old woman with acute promyelocytic leukemia (APL) who died of massive hemoptysis is reported. Chest radiography revealed changes that began with a small focal infiltration and progressed to a large round nodule with cavity formation. Postmortem examination showed the nodule to be composed mainly of infarcted lung tissue with saprophytic growth of Mucor. An adjacent proximal branch of the left pulmonary artery was thrombosed with mucoraceous hyphae, and it had ruptured into the cavitary space around the necrotic tissue and then into a conducting bronchus. In general, both fatal massive hemoptysis and cavity formation are rare in pulmonary mucormycosis. In our present case, the histological findings suggested that both phenomena were closely related to the pulmonary infarction caused by Mucor invasion of the pulmonary artery.

Female↗