Biomedical subjects

N Suzuki

Publications and source records attributed to N Suzuki.

At least 505 records · Page 28Linked to original sources

PubMed1998

Analysis of genetic diversity in the VP1 unique region gene of human parvovirus B19 using the mismatch detection method and direct nucleotide sequencing.

To assess the prevalent genetic types of human parvovirus B19 strains derived from various sources and their relation to particular clinical symptoms, the genetic diversity in the VP1 unique region, which is important for the neutralizing response to human parvovirus B19, was examined by the mismatch detection method using the Non-isotopic RNase Cleavage Assay (NIRCA) and direct nucleotide sequencing. Twenty three samples obtained between 1986 and 1997 were examined. Three electrophoresis patterns were observed with NIRCA. The nucleotide sequence showed that there were 14 nucleotide changes and 4 amino acid substitutions in comparison with Au strains employed as a standard strain. The nucleotide variability of all samples ranged from 0.3 to 2.7% and the amino acid variability ranged from 1.0 to 3.0%. They were classified into three types according to NIRCA. Types 1 and 3 had similar sequences, but the type 2 sequence was quite different. Although there were some nucleotide variations in the same NIRCA type, these were silent. However, there was no relationship between the clinical features and NIRCA types or between clinical features and the nucleotide sequence. All samples obtained before 1987 were NIRCA type 2. On the other hand, 19 of 20 samples obtained after 1989 were NIRCA type 1. The other sample obtained in 1992 was type 3. The results suggest that the B19 strain of type 2 disappeared by 1988 and changed to other B19 strains such as type 1 and type 3 after 1988, indicating a correlation between genome type and prevalence. NIRCA is a convenient method for screening mutations due to its simplicity and quickness.

Adolescent↗

PubMed1998

[Multiple cerebral infarction associated with cerebral vasculitis in rheumatoid arthritis].

A 64-year-old woman was suffering from rheumatoid arthritis since the age of 57. At the age of 62, she manifested episcleritis of the eyes and rheumatoid nodules in the skin, and rheumatoid factor in the blood became high. These findings indicated the presence of systemic vasculitis, and she was treated with prednisolone. At the age of 64, she suddenly became delirious, and T2-weighted and diffusion-weighted MR images revealed fresh infarctions in bilateral temporal and parietal lobes of the cerebrum. MR angiography failed to show any narrowing or obstruction of large cerebral arteries. She had also high fever and arthralgia, and her blood showed elevated levels of white blood cells, erythrocyte sedimentation rate, C-reactive protein, IgG-rheumatoid factor and immune complex. Lumbar puncture revealed an elevated protein level in CSF. A daily dose of 60 mg prednisolone ameliorated these clinical and laboratory findings as well as her consciousness, disclosing disturbances in higher cortical functions including Wernicke aphasia, disorientation, and ideomotor, ideational, and constructional apraxia. Previous 13 reported cases of cerebral infarction complicating rheumatoid vasculitis were mostly described as showing multiple infarctions in cerebral hemisphere, disturbance of consciousness, elevated protein in CSF, and effectiveness of steroid therapy. The present case had these characteristics, and the cerebral vasculitis mediated by IgG-rheumatoid factor and immune complex was indicated as a probable cause of multiple cerebral infarctions.

Arthritis, Rheumatoid↗

PubMed1998

Application of cryoprecipitate as a hematostatic glue.

BACKGROUND: The effectiveness of cryoprecipitate, harvested from a patient's own fresh frozen plasma, for use in cardiac surgery as a hematostatic glue was studied in 32 randomized elective adult cardiac surgery patients from January 1993 to July 1994. MATERIALS AND METHODS: Patients from the Toho Sakura Hospital were randomly allocated to two groups: Group 1 (n=11) received conventional fibrin glue presently available in our institution; while Group 2 (n=21) received autologous cryoprecipitate as a hematostatic glue. Surgical procedures broken down by group were as follows: Group 1: 4 CABG, 5 valvular surgeries and 2 other. Group 2: 11 CABG, 6 valvular surgery, 4 other. We preserved the patient's own blood and stored pure red cell and fresh frozen plasma (FFP). Cryoprecipitate was prepared from the FFP and preserved until required. RESULTS: Cryoprecipitate had a 5-fold increase in fibrinogen activity (1190+/-311 mg/dl vs 238+/-34 mg/dl p<0.001), a 10-fold increase in factor VIII activity (362+/-219% vs 34+/-11%, p=0.001), and 4.5-fold increase in factor XIII activity (538+/-213% vs 119+/-50%, p<0.001), compared to serum. The amount of bleeding postoperatively was slightly lower in the cryoprecipitate glue group compared to the conventional glue group, but this was not significantly different. CONCLUSIONS: We conclude that autologous samples of human cryoprecipitate prepared from a patient's own FFP had a strong hematostatic effect compared to conventional fibrin glue and was a very valuable hematostatic agent during cardiac surgery.

Adhesives↗

PubMed1998

[Trends of prostate cancer: comparison between 1986-90 and 1991-95 at Asahi General Hospital].

Patients with prostate cancer treated during 1986-95 were divided into two groups: the first five years as early period and the recent five years as late period. Background factors, therapeutic modality and prognosis were compared between these two groups. The number of patients during the late period (245) was about 1.5 fold that during the early period (161). The average age for each stage are similar within the same period, and also similar between early and late periods. Almost the same ratios were noticed on stage distribution and on histological grade between early and late periods. Therefore, the increase in the number of patients in recent years was due mainly to expansion with the same proportion of background factors. Patients with T2 and T3 during the late period received more aggressive treatments with/without endocrine therapy. Subsequently these patients seemed to show better prognosis than the patients during the early period. No differences in survival of patients with metastosis was revealed between these two periods. Therefore, the outcome was not improved by recent endocrine therapy.

Androgen Antagonists↗

PubMed1998

Expression patterns of costimulatory molecules on cells derived from human hematological malignancies.

In order to elucidate the possibility of costimulatory molecules-mediated immuno or immuno-gene therapy for human hematological malignancies, we analyzed 30 hematopoietic cell lines and cells obtained from 48 patients with hematological malignancies for the expression of costimulatory molecules such as CD80 and CD86. The 30 hematopoietic cell lines were composed of 4 cell lines derived from the patients with T-cell acute lymphoblastic leukemia (T-ALL), 3 from Philadelphia chromosome positive ALL (Ph1+ALL), 8 from acute myeloblastic leukemia (AML), 3 from acute promyelocytic leukemia (APL), 8 from chronic myeloid leukemia at blast crisis (CML-BC), 3 from Burkitt's lymphoma and one from follicular cell lymphoma. The expression of CD80 or CD86 was frequent on cell lines derived from the patients with CML-BC or Burkitt's lymphoma, while it was rare on cell lines from T-ALL. Subsequently we analyzed the cells obtained from 48 patients with hematological malignancies, which consisted of 6 samples from patients with ALL, 30 from AML, 2 from CML-BC, 3 from B-cell lymphoma and one from each acute mixed leukemia (AMixL), adult T cell leukemia (ATL), T-cell large granular lymphocytic leukemia (T-LGL leukemia), chronic lymphocytic leukemia (CLL), myelodysplastic syndrome (MDS)-RAEB in T, multiple myeloma (MM) or T-cell lymphoma. Among all the 48 cases, all cases except one case with CLL and two with B cell lymphoma were demonstrated to be negative for CD80 on the neoplastic cells. CD86 and HLA-DR were shown to be expressed in 50% and 88% of total 48 cases respectively. In 30 AML samples, CD86 was positive in 15 cases (50%), which was sharply in contrast with the finding that CD80 was not detected in any AML samples. HLA-DR was expressed in 25 AML samples (83%). We also treated seven human hematopoietic cell lines with IFN-gamma, IL-12 or IL-15 and observed whether these cytokines could induce or enhance the expression of CD40, CD54, CD58 and HLA-DR as well as CD80 and CD86. The present study demonstrated that the expression of CD86 could be upregulated not only by IFN-gamma, but also by IL-12 or IL-15 in some cell lines. These findings suggested the possibility that the absence of CD80 on neoplastic cells may be associated with the lack of efficient anti-tumor immunity in most patients with hematological malignancies and that the immuno or immuno-gene therapy manipulating the expression of costimulatory molecules such as CD80 may be a useful treatment modality for hematological malignancies.

Adult↗

PubMed1998

[Diagnosis of pulmonary tuberculosis by the amplicor test for Mycobacterium tuberculosis in induced sputum].

The polymerase chain reaction (PCR) technique was compared with the conventional smear and culture method for the detection and identification of Mycobacterium tuberculosis in 25 induced sputa samples. Sputum induction was performed with an ultrasonic nebulizer using 3% hypertonic saline in 27 previously untreated patients suspected of active pulmonary tuberculosis clue to chest X-ray findings, but who were unable to spontaneously expectorate sputum. All patients received anti-tuberculosis drugs for at least 6 months after sputum induction. Two patients could not expectorate sputum after hypertonic saline inhalation. Microscopy failed to detect positive acid-fast bacilli in 25 induced sputa samples. Induced sputa were both PCR- and culture-positive for 10 patients, PCR-positive and culture-negative for 4 patients, and PCR-negative and culture-positive for 2 patients. These results suggest that the PCR method is useful in diagnosing tuberculosis in induced sputum, and that the results of PCR and culture Procedures can complement each other.

Adolescent↗

PubMed1998

Strain on the gastrocnemii and hamstrings affecting standing balance on an inclined plane in spastic cerebral palsy. A study using a geometric model.

The purpose of this study was to use an non-invasive method to determine whether strain on the gastrocnemii and hamstrings influences postural balance in spastic cerebral palsy (CP). Changes in alignment during standing posture with subjects positioned on a platform that was gradually inclined were measured in 10 normal children and 11 children with CP. The changes in postural alignment were plotted and geometric models used to determine the lines where the gastrocnemii and hamstrings were maximally stretched. In this way the relationship between postural alignment and the amount of strain on the gastrocnemii and hamstrings was investigated. On the inclined platform, which caused ankle joints to become dorsiflexed as the inclination angle increased, the gastrocnemii began to be strained and the hip joints began to be flexed (trunk bent forward) at the same time. In the children with CP, the gastrocnemii were more strained by smaller degrees of inclination. Furthermore, there was one child with CP whose hamstrings were also strained on the inclined platform. We confirmed that postural balance was affected by strain on the gastrocnemii and hamstrings.

Accidental Falls↗

PubMed1998

[A case of endotracheal tube obstruction caused by pneumoperitoneum during laparoscopic cholecystectomy].

A 56-year-old man with cholecystolithiasis was scheduled for laparoscopic cholecystectomy. Anesthesia was induced with pentazocine and propofol i.v., and the trachea was intubated using vecuronium i.v. Anesthesia was maintained with 70% nitrous oxide and 1-3% sevoflurane in oxygen, and vecuronium was used for muscle relaxation. The lungs were mechanically ventilated with a tidal volume of 600 ml and a respiratory rate of 8 cycles.min-1. Following induction of carbon dioxide pneumoperitoneum, blood pressure, PETCO2 and peak inspiratory pressure gradually increased. PETCO2 increased from 33 mmHg to 48 mmHg despite increase in the respiratory rate to 20 cycles.min-1. By 45 minutes after the beginning of surgery, PETCO2 had increased to 60 mmHg, and ventilation of the lungs was impossible. Bronchofiberscopy revealed obstruction of the endotracheal tube by tracheal mucosa. The endotracheal tube was then drawn out by 2 cm with slight recovery of ventilation. After 1 h 16 min of surgery, it was observed that the patient had developed pneumoscrotum and subcutaneous emphysema extending from femoral area, abdomen, and thorax to the right neck. Chest rentogenography revealed a slight tracheal shift and subcutaneous emphysema. One hour after the end of surgery, PaCO2 was 48.9 mmHg under spontaneous respiration. We speculate that the pneumoperitoneum shifted the tracheal carina cephalad, causing obstruction of the endotracheal tube. Our findings show that displacement of the endotracheal tube must be carefully monitored during laparoscopic cholecystectomy.

Anesthesia, Inhalation↗

PubMed1997

Abnormal DNA synthesis activity induced by X-rays in nevoid basal cell carcinoma syndrome cells.

DNA synthesis activity was examined in fibroblasts and isolated nuclei derived from patients with nevoid basal cell carcinoma syndrome (NBCCS) upon exposure to X-ray and ultraviolet (UV). The DNA synthesis activity in NBCCS fibroblasts increased after X-ray irradiation, i.e., to twice that on mock-irradiation, while it decreased in healthy donor-derived fibroblasts. The DNA synthesis activity in isolated nuclei of X-ray irradiated NBCCS fibroblasts also increased, i.e., more than twice that on mock-irradiated. In the experiments using synchronized cells, DNA synthesis activity showed the most marked increase when the fibroblasts at S phase were irradiated with X-rays. In contrast, UV-irradiated NBCCS fibroblasts showed no such increase in DNA synthesis. These results revealed that DNA synthesis is abnormally induced in X-ray irradiated NBCCS cells and that this abnormality might be related with the tendency of tumorigenesis in NBCCS patients after exposure to X-ray.

Ataxia Telangiectasia↗

PubMed1997

Selective inhibitors of cyclic AMP-specific phosphodiesterase: heterocycle-condensed purines.

To reverse the adverse reactions of alkylxanthines and to develop novel inhibitors of cyclic AMP-specific phosphodiesterase (PDE IV), a series of heterocycle-condensed purines were designed and synthesized. Some of these new compounds had similar or more potent and selective inhibitory activity against PDE IV than known PDE IV inhibitors. The tracheal-relaxant activity of these compounds was closely correlated with their PDE IV-inhibitory activity. Moreover, these purine analogues did not have any positive-chronotropic action or adenosine-antagonistic action on isolated heart preparations, which are the particular adverse reactions of alkylxanthines. Among them, 3,4-dipropyl-4,5,7,8-tetrahydro-3H-imidazo[1,2-i]-purin-5-one (1c), which was the most selective and potent PDE IV inhibitor, did not cause emesis in Suncus murinus at a dosage range of 10-100 mg/kg (po), while an imidazole analogue of 1c (4c) and known PDE IV inhibitors such as rolipram and denbufylline caused emesis even at 10 or 30 mg/kg.

3',5'-Cyclic-AMP Phosphodiesterases↗

PubMed1997

Primary structure and differential gene expression of three membrane forms of guanylyl cyclase found in the eye of the teleost Oryzias latipes.

Three cDNAs (OlGC3, OlGC4, and OlGC5) encoding membrane guanylyl cyclases were isolated from a medaka (Oryzias latipes) eye cDNA library. An open reading frame for OlGC3 predicted a protein of 1057 amino acids, and those for OlGC4 and OlGC5, 1134 and 1151, respectively. These proteins consist of an apparent signal peptide (21 residues for OlGC3, 50 residues for OlGC4, and 48 residues for OlGC5) and a single transmembrane domain that divides the protein into an amino-terminal extracellular domain and a carboxyl-terminal intracellular domain that further divides into a kinase-like domain and a cyclase catalytic domain. Phylogenetic analysis with amino acid sequences of OlGC3, OlGC4, and OlGC5, as well as those of other membrane guanylyl cyclases, indicated that OlGC3, OlGC4, and OlGC5 are members of the sensory organ-specific guanylyl cyclase family. Reverse transcription-polymerase chain reaction and Northern blot analyses demonstrated that OlGC3, OlGC4, and OlGC5 transcripts are present in the eye, which contains more cGMP than the other organs. In addition to being expressed in the eye, OlGC3 transcripts are also present in the brain, heart, liver, pancreas, and ovary, while OlGC4 is present in the liver and OlGC5 in the heart. Reverse transcription-polymerase chain reaction analysis with RNA from unfertilized eggs and embryos showed that OlGC3 and OlGC5 are expressed both maternally and zygotically, while OlGC4 is expressed only zygotically, and that the zygotic expression of these three genes is differentially activated. These results suggest a structural and functional diversity of sensory organ-specific guanylyl cyclases in vertebrates.

Amino Acid Sequence↗

PubMed1997

DNA helicase activity in Werner's syndrome gene product synthesized in a baculovirus system.

The gene responsible for Werner's syndrome (WRN) contains a region homologous to the Escherichia coli RecQ type DNA helicase and was thought to code for a DNA helicase belonging to this helicase family. However, no evidence has been shown before to substantiate this prediction. Here, we show data that the product of the WRN gene is indeed a DNA helicase. The gene product, a polypeptide with a relative molecular mass of 170 kDa, expressed in the insect Spodoptera frugiperda (Sf21) cell and purified by affinity column chromatography contained both the ATPase and DNA unwinding activities characteristic of DNA helicase. Expressions in Sf21, as well as in HeLa cells, showed that the WRN DNA helicase is exclusively transported to the nucleoplasm, which is consistent with its function in DNA metabolism. Our studies on strand displacement suggest that WRN helicase can unwind not only a duplex DNA, but also an RNA-DNA heteroduplex, while the latter reaction seems less efficient. Enzymological features learned from the purified WRN helicase are discussed with respect to the biological function, which remains to be clarified.

Adenosine Triphosphatases↗

PubMed1997

Down-regulation of the defective transcripts of the Werner's syndrome gene in the cells of patients.

Werner's syndrome (WS), an adult progeria, is a recessive genetic disorder caused by the mutations in the DNA helicase gene (WRN). In this study, a comparative northern blot analysis was made for poly(A)+ RNAs extracted from fibroblasts and B-lymphoblastoid cells of WS patients, relatives of patients, and normal individuals. The levels of mutant WRN mRNA from patient cells were significantly lower than those of intact mRNA from the cells of normal individuals by an average of 70%. Furthermore, an extremely low level of WRN mRNA(s), presumably a mixture of mutant and intact mRNAs, was observed for the patient's family members who carry one mutated allele. These results strongly suggest that a relatively low level of helicase mRNA is sufficient to prevent the onset of Werner's syndrome.

Adult↗

PubMed1997

Day-night variation of pituitary adenylate cyclase-activating polypeptide (PACAP) level in the rat suprachiasmatic nucleus.

Adenylate cyclase-activating polypeptide (PACAP) is synthesized in the retinal ganglion cells which terminate on vasoactive intestinal polypeptide neurons in the suprachiasmatic nucleus (SCN), the location of circadian clock. To examine whether PACAP exhibits daily variations in the rat SCN, we measured endogenous PACAP contents throughout the day under 12:12 h light-dark or constant dark conditions. PACAP level was low during the light periods, high during the dark periods, and was stable under constant dark conditions. In the periventricular nucleus of the hypothalamus and cerebral cortex, PACAP content did not show any significant variation throughout the day. Our findings suggest that PACAP content in the SCN may be changed by lighting conditions. Thus, PACAP-containing neurons may play certain roles in the entrainment of circadian rhythms.

Animals↗

PubMed1997

Facilitation of Ca2+ action potential frequency by a small G protein Rab3A in rat pituitary GH3 cells.

GH3 pituitary cells have high tendency to exhibit spontaneous Ca2+ action potentials and their frequency (Ca2+ APF) is increased by treatment with thyrotropin-releasing hormone (TRH). Although spontaneous Ca2+ firing was thought to be significant for the induction of oscillations in cytosolic Ca2+ concentration ([Ca2+]i), little attempt to elucidate the mechanism has been done so far. We demonstrate here that spontaneous Ca2+ APF in GH3 cells was increased 1.5-3 fold, comparable to that for TRH, by injection of guanosine 5'-0-3-thiotriphosphate (GTPgammaS), rab3A effector domain peptide, and phorbol-dibutyrate (PDBu), whereas guanosine 5'-O-(2-thiodiphosphate) (GDPbetaS), H-rab5 peptide, ras peptide, and 4 alpha-phorbol did not. The enhancement of Ca2+ firing by rab3A effector domain peptide was blocked by a protein kinase C (PKC) inhibitor, PKC(19-36). The present study suggests that the spontaneous Ca2+APF may be controlled by small G protein phosphorylated by PKC.

Action Potentials↗

PubMed1997

Sea urchin hatching enzyme (envelysin): cDNA cloning and deprivation of protein substrate specificity by autolytic degradation.

The hatching enzyme (envelysin) of the sea urchin Hemicentrotus pulcherrimus was purified from the medium of hatched blastulae. By cDNA cloning its deduced amino acid sequence and molecular architecture were revealed. The 591-residue precursor with calculated Mr of 66,123 consists of an 18-residue signal sequence, a 151-residue propeptide, and a 422-residue mature enzyme with N-terminal catalytic and C-terminal hemopexin-like domains. As compared with that of Paracentrotus lividus, its amino acid sequence is 69% identical and 10% similar. They share typical structural features with the mammalian MMP gene family members: cysteine switch, zinc-binding signature, methionine-turn, Cys residues near both ends of hemopexin-like domain, etc. However, its propeptide has a 70-residue extra sequence with an Asp- and Glu-rich stretch, supposedly involved in the proenzyme activation by binding Ca2+ ions in seawater. The hinge region is also longer than those of most MMPs, with an extra sequence rich in Thr and Arg residues. Mature 50K enzyme is highly susceptible to autolytic cleavage at Gln(503)-Leu(504), producing the 38K form retaining catalytic activity and substrate specificity against fertilization envelope. The 38K form and 15K fragment were coeluted from a gel-filtration column, suggesting that these two fragments are disulfide-bridged and that the tertiary structure is not much deviated. The 38K form further autolyzed to 32K form by cleaving Tyr(450)-Tyr(451) bond with the loss of protein-substrate specificity, retaining only nonspecific protease activity. Thus, the autolytic release of 2/3 of the C-terminal domain reduced the highly specific enzyme to a common nonspecific protease, implying that the size and structure of almost the entire hemopexin-like domain is essential for the protein substrate specificity. Moreover, autolytic degradation of envelysins from the two species follow quite different pathways despite their high homology in structure. The 38K and 32K forms were inhibited by bovine TIMP-1 with different IC50 values, indicating that its inhibitory activity depends on the extent of the interaction with the C-terminal domain of the enzyme.

Amino Acid Sequence↗

PubMed1997

A possible mechanism for hyperthermic radiosensitization mediated through hyperthermic lability of Ku subunits in DNA-dependent protein kinase.

DNA-dependent protein kinase (DNA-PK), composed of p470 catalytic subunit and p85/p70 heterodimer of Ku autoantigen, is considered a critical enzyme in DNA double-strand break repair. We purified DNA-PK from human leukaemic MOLT-4 cells by successive column chromatography and separated into p470 and Ku subunits by ultracentrifugation in glycerol gradient. We studied hyperthermic stability of DNA-PK holoenzyme and its separated subunits to test a possible role of DNA-PK in hyperthermic radiosensitization. DNA-PK was found to lose its activity rapidly at hyperthermic 44 degrees C, and further, Ku subunits instead of p470 catalytic subunits were found to be sensitive to hyperthermia. These results indicate a possibility that hyperthermic radiosensitization is mediated through the heat lability of Ku subunits of DNA-PK, impairing repair of radiation-induced double-strand break of DNA.

DNA Damage↗

PubMed1997

Efficient immobilization of proteins by modification of plate surface with polystyrene derivatives.

Immobilization of proteins on microplate wells by simple adsorption (e.g., for ELISA) is convenient, but it can be inefficient, especially if proteins are hydrophilic or small in size. This problem was alleviated by the use of polyvinylbenzyl lactonoylamide (PVLA). PVLA is strongly adsorbed to the hydrophobic well surface, and its lactonamide part can be oxidized with periodate to generate aldehydo groups. Proteins are then immobilized covalently to the aldehydo groups by reductive amination under mild conditions. Using this method, henceforth termed the PVLA method, alkaline phosphatase (AP) was immobilized to microplates six- to sevenfold greater than by simple adsorption (as measured by activity). Similarly, the activity of immobilized mannose-binding protein A (MBP-A) was 4- to 8-fold higher by the PVLA method than by simple adsorption. The PVLA-coated plates needed as little as 200 ng of MBP-A per well to have a sufficient amount of MBP-A immobilized for the measurement of binding of 125I-labeled mannosylated bovine serum albumin (125I-Man-BSA), but unmodified plates required as much as 20 micrograms/well MBP-A to obtain the same response. Recommended conditions for the PVLA method are 40 microliters of 2 mg/ml of PVLA for coating, 1 mM NaIO4 for the generation of the aldehydo groups, and a 2-h reductive amination at 37 degrees C between pH 8 and 9 for the protein ligation.

Adsorption↗