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Biomedical subjects

K Shimada

Publications and source records attributed to K Shimada.

At least 361 records · Page 20Linked to original sources
PubMed1999

Levels of 24,25-dihydroxyvitamin D3, 25-hydroxyvitamin D3 and 25-hydroxyvitamin D3 3-sulphate in human plasma.

The concentrations of (24R)-24,25-dihydroxyvitamin D3[24,25(OH)2D3], 25-hydroxyvitamin D3[25(OH)D3] and its 3-sulphate [25(OH)D3(3)S] in the plasma of healthy subjects, patients with chronic renal failure, patients with climacteric syndrome, pregnant women and foetuses were determined using the enzyme-linked immunosorbent assay and high-performance liquid chromatography. 25(OH)D3(3)S was not detected in about one-third of the plasma samples from patients with chronic renal failure (n = 26). The three metabolites in maternal plasma reached the highest levels in the second trimester of pregnancy followed by a decrease to the values obtained in the first trimester. Older healthy women (age range 44-71 years) showed higher levels of 24,25(OH)2D3 and 25(OH)D3 in the plasma than did young healthy women (age range 21-29 years), whereas no clear difference was observed between the older healthy women and patients with climacteric syndrome. The level of 25(OH)D3(3)S in the plasma was higher in the latter patients than in healthy women.

24,25-Dihydroxyvitamin D 3↗
PubMed1999

New metabolic pathway of (24R)-24,25-dihydroxyvitamin D3: epimerization of the 3-hydroxy group.

A new metabolic pathway of (24R)-24,25-dihydroxyvitamin D3 [24,25(OH)2D3] was clarified in the in vivo experiments. After the administration of 24,25(OH)2D3 to rats, a new monoglucuronide of a vitamin D metabolite was obtained from the bile together with 24,25(OH)2D3 3- and 24-glucuronides. The genin of the metabolite was identified as 3-epi-24,25(OH)2D3 in comparison with the synthetic sample based on the data from 1H-NMR, GC/MS, and LC/atmospheric pressure chemical ionization-MS. The conjugation position was determined to be the 24-hydroxy group by the LC/electrospray ionization-MS and -MS/MS/MS combined with derivatization. To our knowledge, this is the first reported instance of the epimerization of the 3-hydroxy group of vitamin D compound with no hydroxy group at the 1alpha-position.

24,25-Dihydroxyvitamin D 3↗
PubMed1999

[Development of analysis of vitamin D metabolites].

Vitamin D (D) plays important roles for homeostasis of serum calcium and so on, in human after metabolic activation. The measurements of concentrations of D metabolites in biological fluids are important for clinical and nutritional diagnoses. In these respects, developments of analysis of D metabolites, especially the phase I reaction products (free metabolites), have been carried out. In the first part of this report, the advance in developments of analysis of the free metabolites is reviewed according to the methodology over the last five years. The phase II reaction products (conjugated metabolites) of D, which are poorly understood compared to the free metabolites, are recently found in many kinds of animals, and much interest is focused on their physiological roles. In the second part, an overview of the identification and quantification of the conjugated D metabolites in biological fluids is presented mainly from our studies.

Animals↗
PubMed1999

Cone-beam CT angiography of the thorax: an experimental study.

The authors recently developed a cone-beam computed tomography (CT) scanner and this report presents their evaluation of its potential for thoracic vascular imaging. An X-ray tube and a video-fluoroscopic system were rotated around the objects and 360 projected images were collected in a 12-s scan. Each image was digitized and a 3 dimensional (D) image (256x256x256 voxel volume with a voxel dimension of 0.9x0.9x0.9 mm) was reconstructed. Two different 3D-CT angiographies were investigated in 2 pigs: right atriography and thoracic aortography. Each pig was anesthetized, mechanically ventilated and positioned within the scanner. Contrast agent was infused through the right atrium or the aortic root at a rate of 3 ml/s during the scan. The right atriography scan clearly delineated the anatomy of the pulmonary artery, heart chambers and thoracic aorta. The thoracic aortography scan also clearly delineated the aortic anatomy including the internal thoracic and intercostal arteries. In conclusion, cone-beam CT angiography is potentially useful for thoracic vascular imaging.

Angiography↗
PubMed1999

Angiotensinogen and angiotensin-converting enzyme genotypes, and day and night blood pressures in elderly Japanese hypertensives.

There are inconsistent reports that the angiotensinogen (ATG) variant Met235-->Thr (T235) allele and angiotensin-converting enzyme (ACE) insertion/deletion (I/D) variants are associated with hypertension and related target organ damage. Both high blood pressure (BP) and abnormal diurnal BP variation patterns are related to target organ damage, but it is not known whether the above genetic variants of the renin-angiotensin system are related to 24 h BP and the diurnal BP pattern in Japanese. We studied the association of the ATG T235 allele and ACE D allele with 24 h BP and diurnal BP variation in 235 of 262 consecutive untreated (or off medication) elderly Japanese hypertensives who underwent 24 h ambulatory BP monitoring. There was no significant association between the T235 or ACE D allele with office BP, but the T235 allele was significantly associated with 24 h BP and day BP, and the D allele was significantly associated with increased 24 h BP, day BP, and night BP. There were no effects of the T235 or D alleles on any BP parameters. Those with white-coat hypertension had a significantly lower T235 allele frequency (0.68) than those with sustained hypertension (0.79, p=0.010), but the difference in D allele frequency was marginal (0.30 vs. 0.38, p=0.057). In conclusion, in elderly Japanese hypertensive individuals, both the ATG T 235 and ACE D alleles are associated with increased 24 h BP and day BP, while only the ACE D allele is associated with increased night BP.

Aged↗
PubMed1999

Seroepizootiological survey of Japanese encephalitis virus and Getah virus in regional horse race tracks from 1991 to 1997 in Japan.

A sero-epizootiological survey was conducted for Japanese encephalitis virus (JEV) and Getah virus (GeV) at 10 to 20 regional horse race tracks from 1991 to 1997 in Japan. It was observed that geometrical mean (GM) antibody titer to JEV and GeV was 10 to 50 times higher than others at several race courses (RCs) almost every year. Of them, several race horses showing high antibody titer, which were suggested to be infected with the virus, were also observed in this survey. These data suggested that the viruses have spread among race horses almost every year in Japan, although, fortunately, no horse showing clinical illness due to these viruses was observed. The calendar years and the names of the race courses in which the spread of JEV was suggested were Sonoda and Nakatsu RCs in 1991, Nakatsu RC in 1992, Arao RC in 1993, Nagoya RC in 1994, Kaminoyama, Urawa, Saga and Arao RCs in 1995 and Ooi and Saga RCs in 1997. Spread of JEV was not observed in 1996. The calendar year and name of the race courses at which the spread of GeV was suggested were at Ooi, Sonoda and Nakatsu RCs in 1991, Arao RC in 1992, Nakatsu RC in 1994 and 1995, Funabashi RC in 1996, Saga RC in 1997. It was suggested that surveillance of JEV and GeV should be continued in the future in at least the southern to middle parts of Japan. It has also been suggested that it is necessary to promote the wider use of vaccines to persons related to horse racing.

Alphavirus↗
PubMed1999

Atrial fibrillation and continuous hypotension induced by sildenafil in an intermittent WPW syndrome patient.

A 55-year-old Japanese man was hospitalized for palpitations and severe chest oppression one hour after he ingested about 1500 ml of beer and sildenafil (Viagra) 50 mg. At 43 years of age, he had been diagnosed with intermittent WPW syndrome following a paroxysmal supraventricular tachycardia (PSVT) attack. He took a 1 mg tablet of doxazosin daily for mild hypertension. On admission, his blood pressure was 90/54 mmHg and his heart beat was weak and irregular with a rate of about 220/min. Since atrial fibrillation (Af) was diagnosed on an electrocardiogram (minimum RR interval; 0.22 seconds), direct current shock was performed with 100 joules and 150 joules but conversion to sinus rhythm failed. Sinus rhythm returned spontaneously from Af four hours after taking sildenafil. Since blood pressure was 50/17 mmHg despite the return to sinus rhythm, blood pressure was maintained by dopamine for twelve hours after sinus rhythm returned. The patient underwent catheter ablation for curative therapy and thereafter has not had any further episodes of tachycardia.

Atrial Fibrillation↗
PubMed1999

Alpha-adrenergic blockade in preventing posttransplant edema of lung allograft.

Effect of alpha-adrenergic blockers on pulmonary edema in lung transplantation was studied with a rat model of syngeneic left lung transplantation. Prior to harvesting, 0.1 mg of Prazosin or 0.4 mg of Yohimbine was given to the donor. Pulmonary and systemic hemodynamics were measured under the right pulmonary arterial occlusion (RPAO) at different time points after grafting. Wet to dry weight ratio (W/D) of all transplants was also calculated. Same procedure was conducted in rats with normal and ischemic lung and in transplanted animals without any treatments. While RPAO did not increase W/D in normal lung with a significant elevation in pulmonary arterial pressure (PAP), both these values significantly increased in transplanted lung. Transplanted animals could not tolerate RPAO 24 hours after grafting, but were tolerable later than 48 hours with elevated W/D and PAP. On the contrary, animals given Prazosin or Yohimbine were all tolerable at 24 hours postsurgery. Yohimbine significantly improved W/D. Consequently, it was demonstrated that pulmonary edema of the graft reached its peak during first 24 to 48 hours after transplantation and was alleviated by the blockade of alpha-adrenergic receptor in the graft vessel.

Adrenergic alpha-Antagonists↗
PubMed1999

Intranephron distribution and regulation of endothelin-converting enzyme-1 in cyclosporin A-induced acute renal failure in rats.

Endothelin-1 (ET-1) is thought to play a significant role in acute renal failure induced by cyclosporin A (CsA). The cDNA sequence encoding endothelin-converting enzyme-1 (ECE-1), which produces the active form of ET-1 from big ET-1, was recently reported. To elicit the role of ECE-1 in the glomerular and tubular dysfunction induced by CsA, the effects of CsA on mRNA and protein expression of ECE-1 in rat kidney and on mRNA expression of prepro-ET-1 and ET A- and B-type receptors in glomeruli were studied. ECE-1 mRNA was detected in glomeruli and in whole nephron segments. ECE-1 mRNA expression was downregulated in all nephron segments at 24 h after CsA injection. Protein levels were also downregulated in glomeruli and in the outer and inner medulla. CsA rapidly increased prepro-ET-1 mRNA expression in glomeruli at 30 to 60 min after injection; this rapid increase was followed by an increase in plasma ET-1 levels. These increases were followed by decreased expression of ECE-1, ET A-type receptor, and ET B-type receptor mRNA at 6 h after injection, and serum creatinine levels were increased at 24 h after CsA injection. It is suggested that downregulation of glomerular and tubular ECE-1 expression may be caused by increased ET-1 synthesis in CsA-induced acute renal failure.

Acute Kidney Injury↗
PubMed1999

Relationship between levels of aspartate aminotransferase in gingival crevicular fluid and conventional measures of periodontal status assessed using PocketWatch: a cross-sectional study.

The aim of this cross-sectional study was to determine, using PocketWatch, the relationship between the level of aspartate aminotransferase (AST) in gingival crevicular fluid (GCF) and conventional measures of periodontal status, such as probing depth, attachment level, bleeding on probing and gingival index, in patients with untreated chronic periodontitis. A total of 15 patients with chronic periodontitis were enrolled. Their periodontal status and AST levels in their GCF were measured (n = 93) and statistically analyzed. There was a statistically significant difference in AST levels between diseased periodontal sites and healthy sites (p < 0.0001). The coefficients of correlation between AST levels and probing depth, attachment level and gingival index at all sites were 0.436, 0.266 and 0.468 (Spearman rank correlation). The correlation coefficients were too small to show a definite relationship between AST levels and individual measures of clinical periodontal status. However, AST levels may help to confirm clinical observations in patients with chronic periodontitis before therapy, since AST levels differentiate active and inactive periodontal diseased sites.

Adult↗
PubMed1999

[Coronary artery bypass grafting technique to minimize the usage of metallic materials].

Some metallic materials are widely used for coronary artery bypass surgery. There is no problem using the metallic materials themselves. However, metallic artifact interferes with the interpretation and reduces the sensitivity of the MRI. To minimize the utilization of metallic materials, we applied absorbable nonmetallic clips and used an ultrasonically activated scalpel to harvest the arterial grafts. We also applied polyester suture instead of the stainless steel sternal wire. We believe this technique will allow increased MRI usage for patients who undergo coronary artery bypass surgery.

Coronary Artery Bypass↗
PubMed1999

[Experience with surgery for congenital esophago-bronchial fistula with esophageal diverticulum in adult].

A 65-year-old female was admitted into our department with complaint of bloody sputum. An upper G-I series examinations and thoracic CT demonstrated an esophago-bronchial fistula with diverticulum located between the mid-esophagus and right B6. Following postero-lateral thoracostomy, the fistula was surgically removed and right lower lobectomy was carried out. No inflammatory changes were found in the surrounding tissues of the fistula and the diverticulum. Histological examination revealed that the fistula wall contained squamous epithelium and muscularis mucosa. These results suggested that this case was congenital esophago-bronchial fistula categorized as Braimbridge type I.

Aged↗
PubMed1999

[Urodynamic studies on the untethering of spinal lipoma in the children].

We performed conus untethering on 44 children with spinal lipoma. In this retrospective study, we studied urological examinations obtained in 36 consecutive patients. Urological examinations were ultrasonography of bladder and kidney, voiding cystourethrography (VCG), and urodynamic cystometry. In those of them, 6 patients had already had urinary dysfunction at preoperative stage, but 4 patients' spinal lipoma was one complication of cloaca exstrophy and 2 patients' spinal lipoma after repairment of their myelomeningocele. In the remaining 30 cases, 18 patients (60.0%) as the group 1 did not have urinary dysfunction and abnormality in any urological examinations. Another 7 patients (23.3%) as group 2 also did not have urinary dysfunction, but abnormal vesicoureteral reflux (VUR) was found out in their VCG examination. At postoperative stage, abnormal VUR resolved or improved in all these 7 cases, but one of them showed transient urinary retention. Two patients of 18 in the group 1 had to require clean intermittent self-catheterization at postoperative stage. These observations confirmed that children with spinal lipoma were more likely to present with urological findings, and so it was imperative that a diagnosis be made and treatment be instituted as early as possible.

Child, Preschool↗
PubMed1999

[Results of questionnaire to 56 medical institutions about clinical trials of cancer chemotherapy].

From the stand point of investigators doing clinical trials of anti-cancer drugs, a questionnaire to survey of the current status of clinical trials concerning on the reactions of medical institutions to the new GCP started in April 1997, sent to 75 institutions all over the Japan. 56 institutions (75%) gave answers to the questionnaire, in August 1998. As the results, apparent decrease of Phase II & III trials were noticed compared the numbers before March 1997. IRB with one or two outside members are well functioned in these institutions. But, training related doctors, nurses (especially CRC) are nowadays most important problems, which are strongly expected to Ministry of Health and Welfare and related medical societies, for instance Japan Society of Clinical Oncology.

Antineoplastic Combined Chemotherapy Protocols↗
PubMed1999

[Advances in endoscopic therapies for cancers of the digestive tract].

Endoscopic therapies for the treatment of cancers of the digestive tract have been improved. Today, some early cancers can be curatively treated by endoscopy (endoscopic polypectomy, endoscopic mucosal resection, heatprobe method, etc.). In addition, endoscopic local injection chemotherapy is performed for some advanced cancers as an adjuvant therapy. Recent progress in endoscopic therapies for cancer is reviewed in this paper, including their historical background. Improvements in these endoscopic treatment methods are expected to provide increased advantages for the treatment of patients with cancer in the near future.

Colonic Polyps↗