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Biomedical subjects

A Nakagawa

Publications and source records attributed to A Nakagawa.

At least 19 recordsLinked to original sources
PubMed1992

Crystallization and preliminary X-ray investigation of proteinase A, a non-pepsin-type acid proteinase from Aspergillus niger var. macrosporus.

Proteinase A from Aspergillus niger var. macrosporus is a non-pepsin-type acid proteinase distinctly different in various properties from the family of pepsin-type aspartic proteinases, and so far it remains unknown which residues participate in the catalysis of the enzyme and how the mechanism operates. The acid proteinase A was crystallized from an ammonium sulfate solution by the hanging-drop vapor diffusion method. The space group of the crystals was P2(1)2(1)2(1) with unit cell dimensions of a = 54.7 A, b = 70.4 A and c = 38.0 A. On the assumption that there is one enzyme molecule in the asymmetric unit, the calculated ratio of volume to unit protein mass (Vm) was 1.64 A3 per dalton. Diffraction data were collected up to a resolution higher than 1.5 A, using the Weissenberg camera for macromolecular crystallography with synchrotron radiation. The crystal of proteinase A is, therefore, suitable for the structural analysis with a high resolution.

Aspartic Acid Endopeptidases↗
PubMed1992

Islet hormone pulse intervals are dependent upon sampling frequency.

Pulsatile insulin secretion has been reported from a variety of in vivo and in vitro systems. While it is agreed that insulin pulses exist, there is little agreement concerning the basal frequency or interpulse interval either within the same species in vivo, as both long and short term pulses have been reported, or between in vivo and in vitro preparations. We propose that the frequency of sampling may have profound effects upon the calculated pulse interval. Three systems were used to test this hypothesis: 1) artificial test data were designed to produce regular pulses with an exact 11 min period, 2) perfusate insulin concentration from isolated canine pancreata sampled at 1 min intervals and 3) peripheral blood insulin concentrations from human volunteers sampled every 2 and 5 min. Pulse parameters were determined at 1, 2, 5, 20, 15, 30 and 60 min sampling intervals for each data set by the use of the computer algorithms Pulsar and Cycle Detector. The results indicate that for insulin secretory pulses, sampling frequencies longer than 2 min may result in the production of spurious pulse trains with multiple longer term pulse periods. It is concluded that islet hormone secretory pulse period calculations are dependent upon the sampling frequency.

Analysis of Variance↗
PubMed1992

Enzyme-linked immunosorbent assay of CS-518, a thromboxane synthetase inhibitor, in rabbit plasma and platelets.

A competitive enzyme-linked immunosorbent assay (ELISA) was developed for determination of CS-518, a novel thromboxane synthetase inhibitor. Antisera against CS-518 were obtained from rabbits immunized with bovine serum albumin linked to CS-518 via carboxylic acid introduced into the imidazolyl ring (for ELISA-1) or via 6-carboxylic acid directly (for ELISA-2). Each of two CS-518 derivatives was conjugated to horseradish peroxidase by a N-succinimidyl ester method, and it was used as a labeled-antigen in homogeneous combination with antisera. In ELISA-1, CS-518 was detectable in a range of 5pg-1ng, and all cross-reactivities with main metabolites were less than 5%, in contrast to high affinity to the taurine and glucuronic acid conjugates of CS-518 in ELISA-2. Validity of ELISA-1 was confirmed by a high-performance liquid chromatography and ELISA-1 enabled specific determination of CS-518 in plasma samples deproteinized by methanol. When ELISA-1 was applied to determine CS-518 in platelets after oral administration to rabbits, CS-518 uptake up to maximum capacity in platelets (4.2-5.4 x 10(6) M) and slow elimination of CS-518 from platelets (T1/2 = 36-41 hr) were observed independent of CS-518 doses. These results confirm that CS-518 binds to thromboxane synthetase in platelets with high affinity.

Administration, Oral↗
PubMed1992

DNA adduct formation by o-phenylphenol metabolite in vivo and in vitro.

[U-14C]o-Phenylphenol (OPP) was found to bind covalently to calf thymus DNA during a 60 min incubation in the presence of microsomes, but not in their absence, indicating that metabolic conversion of the parent compound, OPP, to an activated form is essential. Postlabeling analysis with bladder DNA of rats fed a diet containing 2% OPP for 13 weeks revealed one major adduct on TLC. In an in vitro postlabeling experiment with calf thymus DNA, both of the major metabolites of OPP, phenylhydroquinone (PHQ) and phenylbenzoquinone (PBQ), formed adducts, but no adducts were observed with OPP. The chemical structure responsible for adduct formation is thought to be the PHQ semiquinone radical intermediate formed during interconversion between PHQ and PBQ. When the oligonucleotides, pd(A)12-18, pd(C)12-18, pd(G)12-18 and pd(T)12-18, were used in vitro, only pd(G)12-18 gave TLC-detectable adducts on treatment with PHQ and PBQ. The covalent binding appears to be rather specific to guanine residues. These results suggest that covalent binding of the OPP metabolite is one of the underlying events in OPP-induced carcinogenesis in rats.

Animals↗
PubMed1992

Body fat distribution and peripheral insulin sensitivity in healthy men: role of insulin pulsatility.

Abdominal fat distribution is associated with insulin resistance in healthy young men. Factors modulating this phenomenon remain unclear. Pulsatile insulin release has been implicated as a potential regulator of insulin action. The relationship of pulsatility of peripheral insulin levels to fat distribution and peripheral insulin sensitivity was examined in 10 healthy men. Fat distribution was determined by the waist to hip ratio. Peripheral insulin sensitivity was assessed by the euglycemic clamp at an insulin infusion rate of 287 pmol/min.m2. Pulsatility of insulin was assessed by sampling every 2 min for 90 min in the basal state. The characteristics of insulin pulses were assessed by the computer program Pulsar. The waist to hip ratio was negatively associated with insulin sensitivity (r = -0.70, P less than 0.05) and insulin pulse interval (r = -0.66, P less than 0.05). The insulin pulse interval was positively correlated with peripheral insulin sensitivity (r = 0.73, P less than 0.05). The insulin interpulse interval was the primary determinant of insulin sensitivity. The increased frequency of insulin pulses may play a role in inducing insulin resistance in individuals with abdominal fat distribution.

Abdomen↗
PubMed1992

Role of lipid modification on a starch-debranching enzyme, Klebsiella pullulanase: comparison of properties of lipid-modified and unmodified pullulanases.

Klebsiella pullulanase is a lipoprotein synthesized as a precursor with a signal peptide, which is processed by lipoprotein signal peptidase. To clarify the role of lipid modification of pullulanase, we purified lipid-modified wild-type and the unmodified (mutant) pullulanases and compared their properties. The Km and Vmax values of both pullulanases for pullulan were the same. The optimal pH and temperature, the stabilities over pH and temperature ranges, the specificity of substrates, and the patterns of inhibition of the lipid-modified and unmodified pullulanases were also the same. However, we found that the wild-type pullulanase formed trimers whereas the unmodified enzyme did not, and that the migrations of the two enzymes on sodium dodecyl sulphate/electrophoresis were different when the samples were applied on the gel without heating. The results presented in this paper and in previous work show that the correct processing and translocation of pullulanase in K. aerogenes require modification of lipid. However, the enzymatic properties and physical stabilities of pullulanase were not affected by the lipid modification.

Electrophoresis, Polyacrylamide Gel↗
PubMed1991

Enzyme immunoassay of human plasma 11-dehydrothromboxane B2.

11-Dehydrothromboxane B2 (11-dhTXB2) is a proposed marker compound for thromboxane A2 formed in vivo. An enzyme immunoassay was established for determination of the plasma concentration of this compound. The assay was based on a horseradish peroxidase-linked immunoassay utilizing polyclonal anti-11-dhTXB2 antibody obtained from a rabbit, and enabled determination of 11-dhTXB2 in the range of 2 to 500 pg/tube with an IC50 of 36 pg. The cross-reactivities with TXB2, 2,3-dinor-TXB2 and other prostanoids were less than 0.05%. Validity of the enzyme immunoassay was confirmed by a radioimmunoassay utilizing a monoclonal antibody. The plasma 11-dhTXB2 was immunoaffinity-purified by one step using an immobilized monoclonal antibody. The mean plasma level of 11-dhTXB2 in six male volunteers was 4.0 +/- 0.3 pg/ml by this enzyme immunoassay.

Biomarkers↗
PubMed1991

[Qualitative assessment of centrilobular emphysema using computed tomography].

The ability of computed tomography (CT) in the qualitative assessment of centrilobular emphysema (CLE) was studied, with special reference to the morphological relationship between emphysematous change and relatively large bronchovascular bundle forming the margin of secondary pulmonary lobule. Three autopsied lobes with mild, moderate and severe CLE were fixed by the method of Heitzman. Then high resolution CT (HRCT) was applied to those inflation-fixed lobes, which allowed for direct one-to-one pathologic correlation. Furthermore, HRCT findings of these clinical cases with emphysema were analysed. Emphysematous change in CLE was observed as low-attenuation area (LAA) within the homogeneous background on Ct images. In mild and moderate cases, LAA's were round or oval in shape, however in severe case they were observed to be irregular in shape. The border between LAA and parenchyma was not clearly defined, however in severe case LAA was found to be bordered partially or rather subtotally by the bronchovascular bundle. In mild and moderate cases, LAA's were observed to be distant from relatively large bronchovascular bundle. On the other hand, in severe case, only a small amount of lung parenchyma was left between LAA and bronchovascular bundle. These findings correspond to morphologic characteristics of CLE, that is, the process of emphysematous change tends to take place in the center of the secondary lobule, and even if the lobe is severely destroyed, some portion of the peripheral acinus is still preserved at lobular margin. Thus, CT can help to identify the presence of CLE. Furthermore, CT scan analysis of severe grade emphysema may lead to the differentiation between CLE and panlobular emphysema.

Aged↗
PubMed1991

Simultaneous determination of gemfibrozil and its metabolites in plasma and urine by a fully automated high performance liquid chromatographic system.

Sensitive and specific methods for the simultaneous determination of gemfibrozil (Lopid), a lipid-lowering agent, and its metabolites in plasma and urine are described. The methods are based on a fully automated high performance liquid chromatographic (HPLC) system with fluorescence detection. Urine samples, diluted with acetonitrile, were directly analysed by HPLC using a flow and eluent programming method. In the case of plasma, gemfibrozil and its main metabolites were extracted from acidified samples and the resulting extracts injected into the chromatographic system. The sensitivity was approximately 100 ng/mL for gemfibrozil and its four metabolites using 0.5 mL plasma or urine. An acyl glucuronide of gemfibrozil excreted in human urine after oral administration of the drug was isolated and its structure and stability examined.

Autoanalysis↗
PubMed1991

Morphology and size of embryos recovered from superovulated cows.

A total of 691 normal embryos were recovered from 183 superovulated donor cows on the 5th and 6th days after the first insemination, and were examined for their morphology and size in relation to their developmental stage. There was no significant difference in the thickness of the zona pellucida, the diameter of the cell mass, and the overall diameter of the embryos among zygotes, 2-, 4-, 8- and 16-cell embryos, and morulae. In the blastocyst stage, however, the diameter of the cell mass and the overall embryo diameter were significantly greater and the zona pellucida was significantly thinner than in the earlier-stage embryos. The volume of the blastomere significantly decreased from zygote to morula in proportion to the increase in the number of blastomeres. The volume of the cell mass of 2-cell embryos was decreased by about 30% compared with that of zygotes and no increase in the volume of the cell mass was observed during the progression from 2-cell stage to morula. The diameter of the cell mass and the overall diameter of morulae recovered on the 6th day after the first insemination were significantly greater than those of morulae recovered on the 5th day.

Animals↗
PubMed1991

[Complete response in a case of rectal carcinoma with multiple liver metastasis treated by infuse-a-port].

Much effort has been developed to control of multiple liver metastases of colo-rectal cancer, but the results of various therapies are not necessarily satisfactory. We report here a 73-year female with advanced rectal cancer and multiple liver metastases (H3), who showed a complete response to hepatic arterial infusion of mitomycin C using "Infuse-a-port". Hepatic arterial infusion of chemotherapeutic agents using totally implantable reservoir might be one of the most potent therapies for non-resectable liver metastasis of colo-rectal cancer.

Adenocarcinoma↗
PubMed1991

[CT findings in panacinar emphysema].

We analyzed the CT images (in vivo) of 5 lobes (right middle lobe, 1; left lower lobe, 1; right lower lobe, 3) with panacinar emphysema (PAE) obtained at autopsy or thoracotomy for solitary lung tumor. The lobes were inflation-fixed by the method of Heitzman and sliced axially for a CT-pathologic correlative study. One lobe with mild PAE had normal appearance on CT; however, the other four lobes with PAE demonstrated low-attenuation areas (LAAs) of various shapes and sizes on CT. LAAs were locally distributed on CT slices in one lobe, dominant in the inner zones in two lobes, and diffuse in one lobe. Relatively normal to diminished vasculature was observed within the LAAs of four lobes. These CT findings differed significantly from those of centriacinar emphysema (CAE) as reported in other studies. We conclude that CT is useful in the clinical diagnosis of PAE and its differentiation from CAE.

Aged↗
PubMed1990

Immunoaffinity purification of 11-dehydro-thromboxane B2 from human urine and plasma for quantitative analysis by radioimmunoassay.

11-Dehydro-thromboxane B2 is now considered to be a reliable parameter of thromboxane A2 formation in vivo. An immunoaffinity purification method was developed for radioimmunoassay of this compound contained in human urine and plasma. Monoclonal anti-11-dehydro-thromboxane B2 antibody was prepared and coupled to BrCN-activated Sepharose 4B. Human urine or plasma was applied to a disposable column of the immobilized antibody. After the column was washed with water, 11-dehydro-thromboxane B2 was eluted with methanol/water (95/5) with a recovery of more than 90%. The purified extract was subjected to a radioimmunoassay utilizing 11-[3H]dehydro-thromboxane B2 methyl ester and the monoclonal anti-11-dehydro-thromboxane B2 antibody. The detection range of the assay was 10-600 fmol (IC50 = 90 fmol). The cross-reactivities of the antibody with thromboxane B2, 2,3-dinor-thromboxane B2, and other arachidonate metabolites were less than 0.05%. These compounds were efficiently separated from 11-dehydro-thromboxane B2 by the immunoaffinity purification. This procedure also allowed the separation of 11-dehydro-thromboxane B2 from unidentified urinary and plasma substances which interfered with the radioimmunoassay. Validity of the results obtained by the radioimmunoassay was confirmed by GC/MS employing selected ion monitoring for quantification.

Adult↗
PubMed1990

A comparative study of groups by age for the intra- and postoperative water and electrolyte management of oesophageal carcinoma.

The present study examined the effects of subtotal oesophagectomy through a right thoracal and abdominal approach, on the postoperative water-electrolyte metabolism and cardio-pulmonary function of patients with thoracic oesophageal carcinoma. The primary water balance, total sodium intake, urinary NAG index, free-water clearance (CH2O), oxygen diffusion function of the lungs to aerate blood (DLO2-Index), and alpha-human atrial natriuretic polypeptide (alpha-hANP) were measured perioperatively until the seventh day. Subjects were divided by age according to whether they were older or younger than 70 years into 2 groups. In both groups, no change was observed in the primary water balance, total sodium intake, urinary NAG index or CH2O. However, all of the patients in the older group exhibited significantly higher alpha-hANP values than those in the control group, and the DLO2-Index was also higher in the former subjects during the first 3 days following surgery. It may be concluded that alpha-hANP is a hormone of considerable importance as it is secreted in large amounts in response to increased stress on the cardio-pulmonary system and serves to normalize the water balance causing this extra load.

Acetylglucosaminidase↗
PubMed1990

S-class cytochromes c have a variety of folding patterns: structure of cytochrome c-553 from Desulfovibrio vulgaris determined by the multi-wavelength anomalous dispersion method.

The three-dimensional structure of cytochrome c-553 isolated from sulfate-reducing bacterium, Desulfovibrio vulgaris Miyazaki F strain, has been determined by the multi-wavelength anomalous dispersion technique with use of synchrotron radiation. The result shows that bacterial S-class cytochromes c have a variety of folding patterns. The relative location of two a-helices at amino- and carboxyl-terminals and the style of bonding to the heme group show "cytochrome c folding," but other regions of the structure are different from those of other cytochromes c previously reported. The results also give useful information about the location of sulfate-reducing bacterium on the phylogenetic tree of the bacterial cytochromes c superfamily.

Amino Acid Sequence↗
PubMed1990

Direct modification of obsessive thinking with messages.

We treated 2 patients with obsessive-compulsive disorders for years using messages, and their symptoms had improved. We provided the messages that utterly disproved the core reason of their fears, and suggested the patients to repeat, listen or read these messages whenever the obsessive thinking occurred. We supposed that the therapeutic intervention we proposed here have the following benefits: 1. This could dispel the patients' fears and correct the contents of obsessive thinking. 2. This could avoid involving others around and remove the disadvantages following the involvement. We discussed the mechanism of this intervention on the basis of the learning theory.

Adult↗