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Biomedical subjects

T Okajima

Publications and source records attributed to T Okajima.

At least 37 records · Page 2Linked to original sources
PubMed1998

Fabrication and characterization of multilayer supermirrors for hard X-ray optics.

Multilayer supermirrors stacked with three sets of Pt/C combinations have been fabricated on a flat float-glass and conical replica foil mirror using a magnetron DC sputtering system, and applied to X-ray optical systems in the hard X-ray region. The design of the supermirror is optimized to obtain the highest integrated reflectivity in the energy band and at the grazing angle concerned. X-ray reflectivities of 30% in the 25-35 keV band at an incidence angle of 0.3 degrees were obtained.

Journal Article↗
PubMed1998

X-ray absorption beamline at the Mitsubishi compact storage ring.

Beamline #5 (BL#5) at the Mitsubishi compact storage ring (MELCO-SR) is a beamline designed to perform X-ray absorption experiments in the 1-5 keV energy range. MELCO-SR is a racetrack-type storage ring with compact superconducting magnets, which is operated at 600 MeV, mainly for X-ray lithography experiments. As the ring is set in a shield wall of 2 m thickness, a point just outside the shield wall of BL#5 is located at 6.8 m from the source point. A small toroidal mirror, located inside the shield wall at 3.4 m from the source, focuses the beam vertically and horizontally onto the 7.3 m point. This simple optical configuration allows us to bring the source point outside of the shield wall, and to collect about 10 mrad horizontally and maintain small footprints on the monochromator crystal. A new 'Cowan type' monochromator, located at 7.4 m from the source and selected for simplicity of design and for stability, will provide a bright high-resolution and stable X-ray beam for use in the X-ray spectroscopy of electronic materials in MELCO.

Journal Article↗
PubMed1998

Malignant transformation of Nakamura type IV gastric polyp with CA 19-9 production.

In a 68-year-old Japanese man, a gastric polyp 24mm in diameter with a stalk 15 mm in diameter was diagnosed as well differentiated adenocarcinoma and treated by endoscopic polypectomy. Histologically, most of the resected tissue was adenoma, and atypical cells were papillarily proliferating to form adenocarcinoma in adenoma, a Nakamura type IV gastric polyp. Infiltration of carcinoma was limited to within the mucosal layer. Immunohistochemical study with anti-CA19-9 antibody revealed positive staining in carcinoma cells. Serum CA19-9 level, which showed slight elevation, returned to the normal range 1 month after the polypectomy. The proliferating cell nuclear antigen (PCNA) labeling index and DNA ploidy pattern were analyzed in the resected tissue. The PCNA labeling index was 30% in carcinoma, 17% in adenoma, and 0.1% in the normal tissue. The DNA ploidy pattern was diploid in adenoma and aneuploid in adenocarcinoma. These findings suggest that gastric adenoma, as well as colonic adenoma, may have the potential for malignant transformation.

Adenocarcinoma↗
PubMed1998

Chronic splanchnic hemodynamic effects of spironolactone with unrestricted sodium diet in patients with compensated cirrhosis.

The purpose of this study is to determine the hemodynamic effects of spironolactone administration associated with an unrestricted sodium diet (salt 10 g) in patients with compensated cirrhosis and portal hypertension. We studied the hemodynamic changes following eight weeks of administration of either placebo (N = 6) or spironolactone (100 mg/day) (N = 6 Pugh-Child's A and 6 B). No significant changes were observed after the administration of the placebo. Spironolactone induced a significant reduction in the hepatic venous pressure gradient (HVPG) (-10.1 +/- 13.3%, P < 0.05), which was associated with a significant reduction of cardiac output (-11.5 +/- 9.3%, P < 0.01), plasma volume (-8.1 +/- 4.7%, P < 0.01), and wedged hepatic venous pressure (-10.5 +/- 11.6%, P < 0.05). There was no significant change in hepatic blood flow and there was no significant correlation between the change in the HVPG and the change in circulating plasma volume. A decrease in the HVPG greater than 10% was observed in eight of 12 patients (67%), defined as responders, at eight weeks. Six of six (100%) grade A patients and two of six (33%) grade B patients responded. This study demonstrated that spironolactone with an unrestricted sodium diet decreased the HVPG in grade A patients but did not significantly decrease the HVPG in grade B patients.

Diuretics↗
PubMed1998

Exchange of nucleoside monophosphate-binding domains in adenylate kinase and UMP/CMP kinase.

Two types of active chimeric enzymes have been constructed by genetic engineering of chicken cytosolic adenylate kinase (AK) and porcine brain UMP/CMP kinase (UCK): one, designated as UAU, carries an AMP-binding domain of AK in the remaining body of UCK; and the other, designated as AUA, carries a UMP/CMP-binding domain of UCK in the remaining body of AK. Steady-state kinetic analysis of these chimeric enzymes revealed that UAU is 4-fold more active for AMP, 40-fold less active for UMP, and 4-fold less active for CMP than the parental UCK, although AUA has considerably lowered reactivity for both AMP and UMP. Circular dichroism spectra of the two chimeric enzymes suggest that UAU and AUA have similar folding structures to UCK and AK, respectively. Furthermore, proton NMR measurements of the UCK and UAU proteins indicate that significant differences in proton signals are limited to the aromatic region, where an imidazole C2H signal assigned to His31 shows a downfield shift upon conversion of UCK to UAU, and the signals assigned to Tyr49 and Tyr56 in the UMP/CMP-binding domain disappear in UAU. In contrast, AUA has a Tm value about 11 degreesC lower than AK, whereas UAU and UCK have similar Tm values. These results together show that the substrate specificity of nucleoside monophosphate (NMP) kinases can be engineered by the domain exchange, even though the base moiety of NMP appears to be recognized cooperatively by both the NMP-binding domain and the MgATP-binding core domain.

Adenylate Kinase↗
PubMed1998

Retinal complications and plasma C5a levels during interferon alpha therapy for chronic hepatitis C.

OBJECTIVE: The pathogenesis of retinal complications, such as retinal hemorrhage and cotton-wool spots formation, during interferon (IFN) therapy is unclear. We studied the relationship between the presence of retinal complications and levels of plasma-activated complement 5 (C5a), a known potent intravascular aggregator of granulocytes, during IFN-alpha therapy. METHODS: Forty-five patients with chronic hepatitis C but without diabetes mellitus and hypertension were studied. IFN-alpha was used 10 MU per day for 2 wk and 3 times weekly for an additional 22 wk. In 25 patients with IFN therapy, the optic fundi were examined before therapy began, every 4 wk thereafter, and whenever patients complained of visual symptoms. C5a levels were measured before, and during the 4th, 8th, 12th, and 24th wk, and at any time that a retinal complication was discovered. Twenty patients served as IFN-untreated controls. They had six optic fundi examinations, each 4 wk apart. C5a levels were measured three times, 4 wk apart, in 10 controls. RESULTS: No retinal hemorrhage or cotton-wool spots were detected before IFN-alpha therapy or in any of the controls. However, retinal hemorrhage occurred in six patients (24%) during IFN-alpha therapy. Five of six episodes occurred within the first 8 wk. Only three patients with retinal hemorrhage had visual symptoms. Cotton-wool spots developed in four patients with retinal hemorrhage. Retinal hemorrhage and cotton-wool spots resolved gradually despite continuous administration of IFN-alpha. Before IFN therapy and in controls, all C5a levels were <7 ng/ml. When retinal hemorrhage occurred, C5a was significantly increased (27.3+/-15.6 ng/ml,p < 0.01) relative to levels from the same patients before and after the hemorrhage (5.7+/-1.1 ng/ml), and also relative to levels in IFN-a-treated patients without retinal hemorrhage (5.7+/-1.1 ng/ml) and compared with levels in IFN-untreated controls (5.4+/-0.7 ng/ml). CONCLUSIONS: Retinal hemorrhage or cotton-wool spots often occur during IFN-alpha therapy for chronic hepatitis C. This study suggests that a high C5a level may be an important step in the pathogenesis of retinal capillary infarction, hemorrhage, and cotton-wool spots formation.

Adult↗
PubMed1998

[Clinical evaluation of hepatic bruit audible in patients with alcoholic hepatitis].

It is well accepted that many patients with alcoholic hepatitis have an audible bruit over the liver (hepatic bruit) in western countries. However, this sign has not been discussed in Japan. The aim of this study was to assess the significance of the hepatic bruit in Japanese patients with alcoholic hepatitis. Hepatic bruit was specifically searched for on auscultation by two physician in consecutive patients (6 alcoholic hepatitis, 58 other alcoholic liver disease, 128 nonalcoholic liver disease including 16 hepatocellular carcinoma). Hepatic bruit was detected in 5 of 6 (83%) patients with alcoholic hepatitis, and in 1 of 16 (6%) patients with hepatocellular carcinoma. In any of other liver diseases, hepatic bruit was not detected. We conclude that hepatic bruit may be an important diagnostic finding in Japanese patient with alcoholic hepatitis as it is in western countries.

Adult↗
PubMed1997

Chronic splanchnic hemodynamic effects of low-dose transdermal nitroglycerin versus low-dose transdermal nitroglycerin plus spironolactone in patients with cirrhosis.

We studied the hemodynamic changes following a four-week administration of either low-dose transdermal nitroglycerin (a constant release of 5 mg of nitroglycerin/day) (N = 10) or low-dose transdermal nitroglycerin plus spironolactone (100 mg/day) (N = 9) in patients with cirrhosis and portal hypertension. Two patients in the latter group did not undergo repeat measurements after dropping out because of severe headaches or developing ascites during the study. Transdermal nitroglycerin induced a significant reduction in the hepatic venous pressure gradient (HVPG) (-11.7 +/- 14.9%, P < 0.05), which was associated with a significant reduction of cardiac output (-10.5 +/- 7.3%). Nitroglycerin plus spironolactone induced a significant reduction in the HVPG (-18.3 +/- 16.0%, P < 0.05) associated with a significant reduction of cardiac output (-13.8 +/- 5.6%), right atrial pressure (-35.0 +/- 30.0%), mean arterial pressure (-7.5 +/- 6.8%), and plasma volume (-10.2 +/- 7.0%). The difference of the mean HVPG reduction between the groups was insignificant. A decrease in the HVPG greater than 10% was observed in six of 10 patients (60%) and in five of seven patients (71.4%), defined as "responders," at four weeks. The difference in percentage of responders between the groups was insignificant. We found that in some cirrhotic patients, low-dose transdermal nitroglycerin is potentially useful in the treatment of portal hypertension. Spironolactone as an adjunct to low dose transdermal nitroglycerin did not demonstrate therapeutic advantages in the treatment of portal hypertension in cirrhotics. That there were nonresponders indicates that there are variable responses in splanchnic hemodynamics to these drugs.

Administration, Cutaneous↗
PubMed1997

[Cerebellar atrophy in Minamata disease: comparison with spino-cerebellar degeneration on MR images].

We evaluated atrophic patterns of the cerebellar vermis in seven patients with Minamata disease (MD) and nine patients with spino-cerebellar degeneration (SCD) on MR images. Twenty-five control subjects were also examined. The cerebellar vermis was divided into superior, middle, and inferior parts by the primary fissure and the prepyramidal fissure on the median sagittal T1-weighted MR image. The length and area of each part were measured. In the patients with SCD, there were no significant differences in the degree of atrophy among the three parts. However, MR images of the patients with MD showed more severe atrophy in the middle and inferior parts than in the superior part. Atrophy of the superior part was less frequently observed in MD patients.

Adult↗
PubMed1996

Interferon-alpha is effective in HTLV-I-associated myelopathy: a multicenter, randomized, double-blind, controlled trial.

A double-blind, multi-center study was performed on patients with HTLV-I-associated myelopathy (HAM) to evaluate the therapeutic effect of treatment with natural interferon-alpha (HLBI). Forty-eight HAM patients were enrolled and treated with either 0.3 MU (n = 15), 1.0 MU (n = 17), or 3.0 MU (n = 16) of HLBI for 28 days. Clinical evaluation included motor dysfunction, urinary disturbances, and changes of neurologic signs. The frequency of therapeutic response judged as excellent to good 4 weeks after starting therapy and 4 weeks after completion of therapy were 7.1% (1 of 14) and 8.3% (1 of 12) in the 0.3-MU group, 23.5% (4 of 17) and 26.7% (4 of 15) for the 1.0-MU group, and 66.7% (10 of 15) and 61.5% (8 of 13) for the 3.0-MU group. The therapeutic benefit in the 3.0-MU group was significantly higher than in the 0.3-MU group. There was no significant difference in the incidence of symptomatic side effects between groups. Abnormal laboratory data were obtained for some patients in the 1.0-MU and 3.0-MU groups; however, the treatment schedule could be continued in most patients. These results suggest that HAM patients may be safely treated with HLBI 3.0 MU every day for 4 weeks with favorable clinical effects.

Adult↗
PubMed1995

Neurologic features of chronic minamata disease (organic mercury poisoning) and incidence of complications with aging.

To elucidate the neurologic features of chronic Minamata disease, and the incidence of complications with aging, we studied 80 patients with documented Minamata disease (organic mercury poisoning) from 1986 to 1994 (mean age: 63 years). Of the cardinal neurologic findings, sensory impairment was seen with highest frequency in 98.8% of patients limited to the extremities in 86.3%. Impairment of lower extremity coordination was observed in 60%, constriction of the visual field in 51.9%, and retrocochlear hearing loss in 41%. To assess age-related complications, patients were separated into three groups by age: Group I (10 to 39 years); Group II (40 to 69 years); Group III (> or = 70 years). The incidences of hypertension and cerebrovascular diseases, organic ophthalmologic disorders (including cataracts), presbyacusis, and cervical spondylosis deformans increased significantly with age. Compared with a preceding survey (1981 to 1985, 171 patients, mean age: 63.5 years), the incidences of complicated hypertension and cataracts had decreased, whereas those of cerebrovascular disease and retinitis pigmentosa remained unchanged. The incidences of abnormal brain computed tomography (CT), presbyacusis, cervical spondylosis deformans, and positive tests for urine sugar also increased. The incidences of these complications other than retinitis pigmentosa were similar to those in the general population. These results accurately reflect the recent epidemiological disease tendencies in Japan toward a decreased incidence of hypertension and an increased incidence of diabetes.

Adolescent↗
PubMed1995

Cloning, sequencing, and expression in Escherichia coli of cDNA encoding porcine brain UMP-CMP kinase.

A cDNA encoding porcine brain UMP-CMP kinase has been isolated using two oligonucleotide probes synthesized on the basis of the partial amino acid sequences of the purified enzyme. The isolated cDNA consisted of 1,626 nucleotides including the coding region for a polypeptide of 196 amino acid residues with a calculated molecular weight of 22,279. The enzyme showed an overall sequence identity of about 40 and 50%, respectively, with adenylate kinases from mammalian muscle and Escherichia coli and UMP-CMP kinases from Saccharomyces cerevisiae and Dictyostelium discoideum. The two highly conserved residues, Thr-39 and Leu-66, in adenylate kinases, which are located close to the adenine ring of the bound AMP, are replaced by Ala and Ile, respectively, at the corresponding positions in UMP-CMP kinases. The entire structural gene was inserted 3'-downstream of the strong promoter in the expression plasmid pET-3b. E. coli BL21(DE3) cells carrying the resultant plasmid produced the active enzyme in a soluble state, most efficiently upon induction at 37 degrees C with 0.02 mM isopropyl-beta-D-thiogalactoside. The purified recombinant enzyme catalyzed specific phosphoryl transfer from ATP to UMP and CMP.

Adenylate Kinase↗
PubMed1995

Neurologic features of chronic Minamata disease (organic mercury poisoning) certified at autopsy.

To better understand the neurologic events related to chronic Minamata disease (organic mercury poisoning), we studied data from 77 patients with Minamata disease as certified at autopsies performed from 1976 to 1994 (mean age: 72.3 years). Major neurologic findings included: sensory impairment in 80.5% of the patients which was limited to the extremities in 42.9%. Impairment of lower extremity coordination was present in 35.8% of the patients, constriction of the visual fields in 28.8%, and retrocochlear hearing loss in 15.3%. There was no correlation between the degree of cerebellar incoordination and the methylmercury concentration in the cerebellum. Compared with the classic type of Minamata disease, the incidence of major neurologic findings was markedly decreased. In light of these findings, supplemental examinations including brain computed tomography (CT), magnetic resonance imaging (MRI), short latency somatosensory evoked potential (SSEP), or tremogram may be necessary to clinically diagnose Minamata disease, especially in atypical or mild cases.

Adult↗
PubMed1995

Oral administration of nipradilol and the acute and chronic splanchnic hemodynamic effects of a new beta-blocker with nitrovasodilating properties in patients with liver cirrhosis.

OBJECTIVES: We studied the effects of nipradilol, which has both a nonselective beta-blocker action and a vasodilating action similar to nitroglycerin, on portal hypertension. METHODS: We measured hepatic venous pressure gradient and splanchnic and systemic hemodynamics before beginning therapy, 2 h after an oral dose of 6 mg, and after either 6 months of nipradilol 6 mg twice a day (n = 14) or of a placebo (n = 6) in 20 cirrhotic patients. RESULTS: No significant changes were observed after the administration of the placebo. Oral nipradilol induced a significant reduction in the hepatic venous pressure gradient (base line: 14.8 +/- 3.2 mm Hg vs 2 h: 12.3 +/- 3.4 mm Hg, p < 0.01; 6 mo: 12.5 +/- 3.2 mm Hg, p < 0.05) without a significant change in the free hepatic venous pressure. The hepatic vascular resistance decreased significantly (base line: 1811 +/- 778 dyn.sec.cm-5 vs 2 h: 1540 +/- 701 dyn.sec.cm-5, p < 0.05; 6 mo: 1564 +/- 693 dyn.sec.cm-5, p < 0.05) without a significant change in hepatic blood flow. A decrease in the hepatic venous pressure gradient greater than 10% was observed in nine patients (64%), defined as "responders," at 2 h and in 10 patients (71%) at 6 months. The reduction of mean heart rate and hepatic venous pressure gradient in these responders was 16.2% and 28.3% at 2 h and 15.1% and 27.1% at 6 months, respectively. CONCLUSIONS: We found that in some cirrhotic patients, at the doses used in this study, long term oral nipradilol administration produces a reduction in the hepatic venous pressure gradient with both a beta-blocking and a nitrovasodilating action.

Administration, Oral↗
PubMed1994

[Hormonal abnormalities were improved by weight loss using very low calorie diet in a patient with polycystic ovary syndrome].

A 27-year old woman was admitted to our hospital because of oligomenorrhea, hirsutism and obesity. Her menstrual period has been irregular since she was 14 years old. Her weight increased rapidly after the age of 15 and she became obese. Hirsutism was noticed at the age of 16. The diagnosis of polycystic ovary syndrome was made on her illness through the endocrinological examinations: (1) The response of LH to LH-RH administration was much higher than that of FSH. (2) The concentration of plasma testosterone was increased. (3) Plasma level of E2 was decreased while that of E1 was increased. (4) CT scan showed bilateral ovarian cyctic masses. In addition, hyperinsulinemia was observed during the 75g glucose tolerance test and the presence of insulin resistance was suggested. As she was overweight (BMI; 33.6 kg/m2), weight loss was expected to improve her hormonal abnormalities. She went on a very low calorie diet of 420 kcal/day (Optifast, Sandoz, USA). When she lost around 9kg of weight, her menstruation period started that has not been observed for the previous 5 months. Plasma levels of LH, FSH and testosterone were lowered following the weight loss. The responses of LH to LH-RH and IRI to glucose were decreased as well. She left the hospital after the second menstruation occurred at the proper period. From these results, the importance of weight loss was suggested in overweight patients with polycystic ovary syndrome. The benefit of very low calorie diet was also noticed since it brought a rapid weight loss as well as rapid improvements of hormonal abnormalities.

Adult↗
PubMed1994

MR findings in seven patients with organic mercury poisoning (Minamata disease).

PURPOSE: To study the long-term MR findings in seven patients with Minamata disease. METHODS: All patients examined were affected after eating daily considerable amounts of the methylmercury-contaminated seafoods from 1955 through 1958 and showed typical neurologic findings. T1- and T2-weighted images were obtained in axial, coronal, and sagittal sections. RESULTS: The visual cortex, the cerebellar vermis and hemispheres, and the postcentral cortex were significantly atrophic. The visual cortex was slightly hypointense on T1-weighted images and hyperintense on T2-weighted images, probably representing the pathologic changes of status spongiosus. CONCLUSION: MR demonstrated the lesions, located in the calcarine area, cerebellum, and postcentral gyri, which are probably related to three of the characteristic manifestations of this disease: the constriction of the visual fields, ataxia, and sensory disturbance, respectively.

Atrophy↗