PubMed Health⌕ Search

Biomedical subjects

N Ban

Publications and source records attributed to N Ban.

At least 55 records · Page 3Linked to original sources
PubMed1994

[Evaluation of physicians' decision making processes in primary care medicine].

To investigate how primary care physicians select appropriate diagnostic tests in their clinical practice, we analyzed the physician's decision making processes by means of written case simulations. We allocated the physicians who participated in this study to three groups; nine residents and ten attending physicians from the Department of Primary Care Medicine, and nine specialists from the Department of Medicine in our hospital. After they read a history and findings in each presented case, the physicians were requested (1) to make diagnostic hypotheses and predict probability of each hypothesis, (2) to select diagnostic tests and their purpose, and (3) to estimate contribution of the tests to the diagnosis. The results revealed that the attending physicians tended to order the diagnostic tests more strictly based on their hypotheses than the residents and specialists did. The attending physicians selected diagnostic tests from specific varieties rather than from "Essential Laboratory Tests" when they were confident in their hypotheses. On the other hand, they selected the tests mainly from "Essential laboratory Tests" when they were uncertain of diagnosis or needed to exclude serious diseases. They regarded the contribution of tests to the diagnosis as high when specific diagnostic tests were available for the presumptive diagnosis, or severe conditions were expected. These findings suggest that, in the setting of primary care practice, the application of laboratory tests depends on the severity of presenting conditions and pre-test certainty of the diagnostic hypothesis. Therefore, it may not be always appropriate to apply "Essential Laboratory Tests" uniformly to every patient irrespective of his/her condition.

Adult↗
PubMed1993

Preliminary crystallographic study of a complex between an Fab of a monoclonal feline peritonitis virus neutralizing antibody and its anti-idiotypic Fab.

A complex between an Fab fragment of an E2 specific feline infectious peritonitis virus neutralizing antibody 730.1.4 and Fab fragment from anti-idiotypic monoclonal antibody 409.5.3, was crystallized from ammonium sulfate using vapor diffusion methods. The complex crystals diffract to about 2.9 A resolution and are of orthorhombic space group P2(1)22(1) with a = 75.2 A, b = 80.6 A and c = 187.6 A. There are two Fab molecules, or one idiotype-anti-idiotype complex, comprising the asymmetric unit. The long 187.6 A c axis suggests that the long axis of the complex might lie along this direction. Although small and radiation-sensitive, crystals are suitable for three-dimensional structural analysis.

Animals↗
PubMed1993

Yeast seryl-tRNA synthetase expressed in Escherichia coli recognizes bacterial serine-specific tRNAs in vivo.

The Saccharomyces cerevisiae serS gene which encodes seryl-tRNA synthetase (SerRS) was expressed in Escherichia coli from the promoter and the ribosome binding sequences contained in its own 5'-flanking region. The low level of yeast SerRS in the prokaryotic host was sufficient to permit in vivo complementation of two temperature-sensitive E. coli serS mutants at the nonpermissive temperature. Thus, yeast SerRS can aminoacylate E. coli tRNA(Ser) species in vivo. Yeast SerRS, isolated from an overexpressing E. coli strain by a rapid two-step purification on FPLC, aminoacylated E. coli tRNA with serine much more poorly (relative kcat/Km = 2 x 10(-4)) than its homologous tRNAs. DL-Serine hydroxamate, an inhibitor of E. coli SerRS, inhibits yeast SerRS in vivo and in vitro with an inhibition constant (Ki) of 2.7 mM, a value 90-fold higher than that for E. coli SerRS.

Amino Acid Sequence↗
PubMed1992

Preliminary crystallographic study of peanut peroxidase.

The cationic isozyme of peroxidase isolated from suspension cultures of peanut cells is a heme-containing and calcium-dependent glycoprotein having four covalently attached oligosaccharide chains. Attempts were made to crystallize the glycoprotein for X-ray diffraction analysis, and these have met with some success. Crystals have now been grown that are suitable for a full three-dimensional structural analysis. The crystals are thin plates and we have shown them to be of the orthorhombic space group P2(1)2(1)2(1) with a = 48.1, b = 97.2, c = 146.2 A. The crystals diffract to beyond 2.8 A resolution, appear to be stable to lengthy X-ray exposure, and contain two molecules of 40,000 daltons each in the asymmetric unit.

Arachis↗
PubMed1991

Characterization of crystals of an Fab fragment of a murine monoclonal antibody.

The Fab fragment of an antibody, made against an E2-specific feline infectious peritonitis virus neutralizing antibody, has been crystallized in a form suitable for X-ray diffraction analysis from PEG 4000 using vapor diffusion methods. The Fab fragment crystals diffract to about 2.9 A resolution and are of triclinic space group P1. Unit cell dimensions, by which the reciprocal lattice can be indexed, are a = 57.16 A, b = 70.85 A, c = 75.81 A, alpha = 85.11 degrees, beta = 121.28 degrees and gamma = 116.33 degrees. There are two Fab fragments comprising the asymmetric unit of the crystals. The presence of a pseudo-mirror plane in the diffraction pattern suggests the presence of at least an approximate dyad axis relating the two Fab fragments within the asymmetric unit.

Animals↗
PubMed1991

Cytomegalovirus DNA in the sera of patients with cytomegalovirus pneumonia.

We attempted to detect cytomegalovirus DNA (CMV-DNA) in the sera of four leukaemia patients who underwent an allogeneic bone marrow transplant (BMT), in six leukaemia patients who suffered from pneumonia and in 16 healthy subjects, using the polymerase chain reaction (PCR). Three of the four BMT patients subsequently developed CMV pneumonia. In two cases, CMV-DNA was detected in the sera at about the time the pneumonia occurred, and the amount of DNA increased with disease progression. The serum of the third patient became positive for CMV-DNA before he developed pneumonia. The fourth patient did not develop CMV pneumonia, but his urine became persistently positive for CMV-DNA soon after the BMT, whereas the serum was negative. A relationship was found between the occurrence of pneumonia and the serum level of CMV-DNA. CMV-DNA was also detected in three of six pneumonia patients whose anti-CMV IgM antibodies were elevated in the circulation. Sera from the 16 normal subjects were negative for CMV-DNA, regardless of their being seropositive or seronegative for CMV. While it had been previously thought that CMV did not exist in serum, we detected CMV-DNA in serum by PCR in the active disease stage. Our results suggest that PCR would be useful for the early diagnosis of CMV pneumonia and in monitoring its course.

Adolescent↗
PubMed1990

Relationship between splenic and superior mesenteric venous circulation.

We took advantage of routine hemodynamic examinations to determine the relationship between splenic and intestinal circulation by infusing prostaglandin E1 into the superior mesenteric artery and observing the portal hemodynamic changes in patients with chronic liver disease. Relative blood flow rate in various vessels of the portal system were measured percutaneously using an ultrasonic duplex system, while portal venous pressure was measured directly using a transducer. The superior mesenteric venous blood flow increased significantly as did the portal venous blood flow and pressure, though the degree of change of portal venous blood flow was less than was expected from the change of portal venous blood flow in the superior mesenteric venous blood flow. Splenic venous blood flow decreased significantly. This decrease is perhaps due to a mechanism that acts to compensate for the increase induced in the superior mesenteric venous blood flow to maintain portal flow at approximately the same level. The measured changes suggest a relationship between splenic and intestinal blood flows that is regulated according to the hepatic circulatory condition. The regulatory mechanism should be considered when designing the treatment of portal hypertension.

Alprostadil↗
PubMed1989

Quantitative measurement of abdominal arterial blood flow using image-directed Doppler ultrasonography: superior mesenteric, splenic, and common hepatic arterial blood flow in normal adults.

To measure volume blood flow quantitatively in human abdominal arteries, we used an ultrasonic image-directed Doppler system and electromagnetic flowmeter to first measure volume flow in canine arteries. In dogs, there was a strong linear correlation (R = 0.98) between the product of the time average of the maximum blood flow velocity and the average cross-sectional area and the volume blood flow measured by an electromagnetic flowmeter. These results enabled measurement of volume blood flow in the human superior mesenteric (SMA), splenic (SPA), and common hepatic (CHA) arteries from the abdominal wall. Comparison of pulsatility index values indicated a larger vascular resistance in the SMA than in the SPA or CHA.

Adult↗
PubMed1989

[Hepatocellular carcinoma--a comparative study of MR imaging and angiography].

We used magnetic resonance imaging (MRI) at 0.2 T and angiography to evaluate hepatocellular carcinoma (HCC) in 43 patients who had not received therapy. Tumor detection rate by MRI was 84%, T2-weighted spin echo imaging being the best detection method, though one case could only be detected by T1-weighted imaging (Inversion Recovery method). The signal intensity of the tumor relative to the surrounding liver parenchyma was studied using MRI, and tumor staining using angiography. Where there was a high signal intensity in the T2-weighted spin echo images there was a corresponding tendency for tumor staining to be marked. MRI demonstrated the inner structure--which resembles random high-intensity threads on a lower-intensity background--of hypervascular tumors. Tumors with capsules appeared with the capsule clearly delineated irrespective of the signal intensity of the tumor itself.

Adult↗
PubMed1989

[Effect of vasopressin on rabbit hepatic energy metabolism evaluated using in vivo P-31 magnetic resonance spectroscopy].

Changes in metabolic state of rabbit livers after administration of vasopressin (10 mU/kg/min d.i.v.) were evaluated using in vivo P-31 magnetic resonance (MR) spectroscopy. Targets were nine normal control rabbits and eight with chronically carbon tetrachloride-damaged livers. A 2.0 Tesla whole-body MR imager was used for measurement. After administration of vasopressin, liver spectroscopy showed a mild ischemic pattern. The inorganic phosphate peak increased statistically significantly (p less than 0.05) both in the normal control group and in the damaged-liver group (20% and 16% above base line value respectively). In the normal control group, there was a statistically significant decrease (p less than 0.05) in the ATP peak to 18% below the base line value while the PME (phosphomonoester) peak increased slightly (about 10%); there was little change in the damaged-liver group. It was thought that the difference between the two groups was due to differences in blood flow mechanism and liver metabolism. Magnetic resonance spectroscopy was considered to be useful in studying the detailed changes in metabolic state of rabbit liver after administration of vasopressin.

Animals↗
PubMed1989

Analysis of hepatofugal flow in portal venous system using ultrasonic Doppler duplex system.

Blood flow directions of the portal trunk, splenic vein, and superior mesenteric vein were studied using an ultrasonic Doppler duplex system in 146 healthy adults, 132 patients with liver cirrhosis, 76 with hepatocellular carcinoma, 32 with idiopathic portal hypertension, 134 with chronic hepatitis, 18 with acute hepatitis, and 142 with other diseases. Spontaneous hepatofugal flow in one or more of the three vessels examined was detected in 14 patients. Spontaneous hepatofugal flow in the portal trunk was detected in three patients with liver cirrhosis. In two of these three patients, the hepatofugal flow in the portal trunk disappeared after medication. This is interesting, since hepatofugal flow may, in fact, be more common than we suspected in patients who, because of the severity of their disease, are not able to undergo invasive examination. Postoperative hepatofugal flow in the portal system was detected in 20 of 71 cases: 15/17 patients after interposition mesocaval shunting, 2/17 after distal splenorenal shunting, 2/31 after splenectomy, and 1/6 after splenic artery occlusion with steel coils. In more than half the cases of interposition mesocaval shunting (9/17 patients), blood flow in the portal trunk was hepatofugal. However, hepatopetal blood flow in the portal trunk was maintained in most cases of distal splenorenal shunting (13/17), showing the merits of this technique as a selective portosystemic shunt operation.

Adult↗
PubMed1988

Activated T-lymphocytes with polyclonal gammopathy in patients with human T-lymphotropic virus type I--associated myelopathy.

Human T-lymphotropic virus type I (HTLV-I)--associated myelopathy (HAM) has been shown to be closely related to HTLV-I infection. However, the mechanism by which this disease occurs after infection with HTLV-I is still obscure. We found that HAM patients have unusually high proportions of CD4+ HLA-DR+ cells, CD8+HLA-DR+ cells, OKT9+ cells, and CD38(OKT10)+ cells in their peripheral blood, all of which suggest the presence of activated T-lymphocytes. Antibody titer against HTLV-I was much higher in HAM patients than in HTLV-I carriers without evident neurological disease (p less than 0.01). Polyclonal gammopathy was also observed in most HAM patients, and 6 of 10 patients were positive for rheumatoid factor. These observations, coupled with the previous observation that corticosteroid therapy improves clinical symptoms in some patients, make it likely that continuous activation of the immune system, initiated by HTLV-I infection, plays a key role in the pathogenesis of HAM.

Antibodies, Monoclonal↗