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Biomedical subjects

H Yamada

Publications and source records attributed to H Yamada.

At least 91 records · Page 5Linked to original sources
PubMed2002

Differences in spatial autocorrelation between four sub-populations of Alnus trabeculosa Hand.-Mazz. (Betulaceae).

To investigate the spatial structure of Alnus trabeculosa Hand.-Mazz, we compared three sub-populations at Imaichi in Tochigi Prefecture and one sub-population at Juo in Ibaraki Prefecture, Japan. A total of 269 trees, covering 0.71 ha in total, were mapped and genetically analyzed using nine enzyme systems encoding 13 isozyme loci. There were no significant differences between the four sub-populations in terms of Na,Ne, H(o), H(e )and F(IS). However, according to spatial autocorrelation analysis, the Juo sub-population, which is younger than the others, showed an aggregation of multilocus genotypes, especially within 25 m radii. In contrast with the Juo sub-population, those in Imaichi showed no clear spatial structuring. In the three Imaichi sub-populations, gametic phase disequilibrium is attributable to heterogeneity of genotype frequencies, but in the Juo sub-population it seems to be due to other factors, connected with the composition of the trees in the sub-population and/or its founder population, gene flow and asexual propagation. To conserve as much as possible of the genes or genotypes in restricted areas, conservation of populations that do not show clear family structures, such as those in Imaichi, would be most effective.

Betulaceae↗
PubMed2002

Prostaglandin E2 down-regulates viable Bacille Calmette-Guérin-induced macrophage cytotoxicity against murine bladder cancer cell MBT-2 in vitro.

The regulatory effect of prostaglandin (PG) E2 and a cyclooxygenase (COX) inhibitor on Bacille Calmette-Guérin (BCG)-induced macrophage cytotoxicity in a bladder cancer cell, MBT-2, was studied in vitro. BCG stimulated thioglycollate-elicited murine peritoneal exudate cells (PEC) to induce cytotoxic activity and to produce cytokines such as interferon (IFN)-gamma, tumour necrosis factor (TNF)-alpha and PGE2. NS398, a specific COX-2 inhibitor, and indomethacin (IM), a COX-1 and COX-2 inhibitor, enhanced viable BCG-induced cytotoxic activity and IFN-gamma and TNF-alpha production of PEC. However, NS398 and IM did not enhance these activities induced by killed BCG. Enhanced cytotoxicity was mediated by increased amounts of IFN-gamma and TNF-alpha. Exogenous PGE2 reduced cytotoxic activity and IFN-gamma and TNF-alpha production of PEC. These results suggest that PGE2 produced by BCG-activated macrophages has a negative regulatory effect on the cytotoxic activity of macrophages. Accordingly, a PG synthesis inhibitor may be a useful agent to enhance BCG-induced antitumour activity of macrophages.

Animals↗
PubMed2002

Expression of calbindin-D9k messenger ribonucleic acid in the gastrointestinal tract of dairy cattle.

The calcium demands of pregnancy and lactation are known to up-regulate expression of Calbindin-D9k (CaBP-9k) mRNA in the intestines. The gastrointestinal CaBP-9k mRNA expressions has not been studied in dairy cows, which are bound to experience several pregnancies and lactation stages. In this study, the CaBP-9k mRNA expression were examined in the gastrointestinal tract of Holstein dairy cattle by Northern blot analysis. Detectable expression of CaBP-9k mRNA was localized in the proximal portion of the small intestines. These expressions were higher at the most proximal region of the duodenum and gradually decreased distally. The duodenal CaBP-9k mRNA was detected in all dairy cattle from 0.4 to 83.4 months old, but was not detectable in foetuses. There were no significant correlations between the age and the levels of CaBP-9k mRNA expression or between the plasma 1,25-(OH)2D3 concentrations and the levels of CaBP-9k mRNA expression.

Age Factors↗
PubMed2002

Successful treatment of chromomycosis using carbon dioxide laser associated with topical heat applications.

A 59-year-old Japanese man presented with a slightly elevated, pruritic, erythematous plaque on his left buttock measuring 5 x 5 cm in diameter. The man had a history of chromomycosis, dating 6 years prior to the current consultation, for which he had been treated with oral terbinafine. Diagnosis of a recurrence of chromomycosis of the skin due to infection by Foncecaea pedrosoi was made after careful analysis of the clinical features, skin biopsy, KOH mounts, and fungal culture results. We administered topical heat therapy followed by treatment with CO2 laser to eradicate the unresponsive remnants of the lesion. The operative site re-epithelized within 10 weeks, and 1 year after the treatment there was no evidence of recurrence. For a recalcitrant case of chromomycosis, as in this case, the use of CO2 laser combined with topical heat therapy may be a new therapeutic modality.

Carbon Dioxide↗
PubMed2002

Mycobacterial infection in natural killer T cell knockout mice.

To gain a better understanding of the pathological role of natural killer (NK) T cells in murine tuberculosis, NKT knockout (KO) mice (J(alpha)281(-/-)mice) were utilized. Eight-week-old NKT KO mice of BALB/c origin and wild-type (WT) mice were infected with Mycobacterium tuberculosis Kurono strain by the airborne route using an airborne infection apparatus, and their capacity to control mycobacterial growth, granuloma formation, and cytokine production were examined. The NKT KO mice developed granulomatous lesions in the lungs; there was no statistically significant difference in pulmonary granuloma size between NKT KO and WT mice (p<0.01). The average CFU values increased 3 weeks post-infection, but decreased 9 and 11 weeks post-infection, in the lungs of NKT KO mice. When stimulated with Kurono strain in vitro, splenic cells from NKT KO mice produced less IFN-gamma than did those from WT mice. Expression of mRNA for IL-2, IL-4, IL-6, IL-10 and IL-12 p40 was slightly lower in NKT KO mice compared with WT mice. Our data indicate that NKT cells play a detrimental role in late-phase mycobacterial infection, although Th1 cells are essential in early-phase mycobacterial infection.

Animals↗
PubMed2002

Clinical study comparing bleeding and nonbleeding rectal varices.

BACKGROUND AND STUDY AIMS: Although rectal varices constitute an important cause of lower digestive tract bleeding in patients with portal hypertension, the etiology and pathology of rectal varices remains controversial, and adequate treatment for rectal varices has yet to be established. In this study, we evaluated rectal varices to identify any common characteristics of varices which are susceptible to hemorrhage. PATIENTS AND METHODS: The patients included 40 individuals with rectal varices among 425 patients with portal hypertension who had been treated in our institution. We retrospectively examined patient data regarding underlying hepatic diseases, hepatic function and endoscopic findings with regard to varices. RESULTS: Bleeding from rectal varices occurred in 15 of the 40 patients. Although the prevalence of hemorrhage tended to increase with exacerbation of hepatic dysfunction, no significant differences were found. Similarly, although the incidence of hemorrhage tended to be somewhat higher in patients who had undergone any treatment for complicated esophageal varices than in patients who had not, no significant difference was found. The prevalence of hemorrhage from rectal varices significantly increased in rectal varices of more advanced form, and the prevalence was significantly higher in patients with positive "red color" sign. CONCLUSIONS: The prevalence of hemorrhage from rectal varices was significantly higher in patients with rectal varices of advanced form and/or with a positive "red color" sign.

Aged↗
PubMed2002

Intestinal immune system modulating polysaccharides in a Japanese herbal (Kampo) medicine, Juzen-Taiho-To.

A commercially available dried extract (TJ-48) of Japanese herbal (Kampo) prescription, Juzen-Taiho-To has been found to enhance functions of Peyer's patch cells (intestinal immune system modulating activity) in vitro and in vivo. When TJ-48 was fractionated, the dialyzable fraction (F-3) and the polysaccharide fraction (F-5) expressed the in vitro activity. Oral administration of F-5 (150 mg/kg/day) to mice showed the intestinal immune system modulating activity. When the galacturonan moiety of pectic polysaccharides in F-5 was degraded enzymatically by endo-polygalacturonase, the digestion products significantly increased the activity of F-5. Purification the polygalacturonase-digested F-5 indicated that the active substances were composed mainly of the enzyme-resistant or undigestable polysaccharide molecules. Gel filtrations and anion-exchange chromatographies of F-5 gave 12 kinds of polysaccharides, and among them, 7 polysaccharides had significant intestinal immune system modulating activity. Component sugar analysis suggests that some active polysaccharides are grouped into pectic polysaccharides containing arabinogalactan or heteroglycan chains. Single radial gel diffusion analysis using beta-D-glucosyl-Yariv antigen indicated that some of the active polysaccharides comprised arabino-3,6-galactan moiety, and this moiety was suggested to play an important role partly for expression of the activity by single linear regression analysis between degree of the activity and reactivity with beta-D-glyucosyl-Yariv antigen.

Adjuvants, Immunologic↗
PubMed2002

Feasibility of myocardial dual-isotope perfusion imaging combined with gated single photon emission tomography for assessing coronary artery disease.

The clinical feasibility of both dual-isotope single photon emission tomography (SPET) and gated SPET have been described. The present study evaluates the feasibility of combining gated SPET with exercise 201Tl/rest 99mTc-tetrofosmin dual-isotope SPET corrected for scatter. Ninety-one patients with known or suspected coronary artery disease underwent cardiac catheterization and coronary angiography. Twenty-nine of them underwent exercise 201Tl/rest 99mTc-tetrofosmin dual-isotope SPET with a second 201Tl injection 3 h after the initial 201Tl injection (protocol 1). We then segregated a Bull's eye polar map into three coronary artery territories and quantified the relative regional uptake. The remaining 62 patients underwent exercise 201Tl/rest 99mTc-tetrofosmin dual-isotope SPET combined with gated SPET. We visually evaluated exercise and rest images from the three coronary artery territories. Left ventricular (LV) function was assessed globally by means of the LV ejection fraction and regionally by means of visual scoring analysis, compared with left ventriculography (LVG). The correlation between rest 99mTc-tetrofosmin and 201Tl reinjection images in 87 areas of coronary artery territory (r=0.89, P<0.01) and in 13 infarcted areas (r =0.94, P<0.01) was very close in protocol 1. The overall values for vessel-related sensitivity, specificity and accuracy were 88%, 79% and 82%, respectively, in protocol 2. The correlation between gated SPET and LVG was significant and linear with respect to the LV ejection fraction (r=0.77, P<0.01). The wall motion score from visual evaluation in gated SPET revealed a close overall agreement with LVG (concordance rate, 88%; kappa, 0.670). Exercise 201Tl/rest 99mTc-tetrofosmin dual-isotope SPET with scatter correction for assessing the coronary artery disease offers excellent diagnostic accuracy and the additional gated SPET provides useful information about LV function similar to that for LVG. This sequential protocol requires only 2 h to generate much useful clinical information.

Aged↗
PubMed2002

Pulmonary granulomas of guinea pigs induced by inhalation exposure of heat-treated BCG Pasteur, purified trehalose dimycolate and methyl ketomycolate.

This study was designed to determine the identity of granulomatogenic substances in Mycobacterium bovis BCG Pasteur. When heat-treated BCG Pasteur bacilli were introduced into the lungs of guinea-pigs by an inhalation exposure apparatus, pulmonary granulomas without necrosis developed. Furthermore, when four kinds of mycolates derived from M. tuberculosis Aoyama B strain were introduced into the lungs by the same method, only trehalose 6,6'-dimycolate (TDM) and methyl ketomycolate induced pulmonary granulomas without central necrosis. The pulmonary granulomas consisted of epithelioid macrophages and lymphocytes. When a mixture of TDM and anti-TDM antibody was introduced into the lungs, development of granulomatous lesions was reduced. These data indicate that TDM and methyl ketomycolate are potent granulomatogenic reagents.

Administration, Inhalation↗
PubMed2002

Anticholinergic drugs: response of parkinsonism not responsive to levodopa.

A 41 year old man with parkinsonism and pyramidal signs is described. He was non-responsive to levodopa and dopamine receptor agonists but dramatically responded to trihexyphenidyl. In this patient, brain MRI showed bilateral hyperintensities along the corticospinal tracts on T2 weighted images. PET studies showed a decrease in (18)F-6-fluorodopa uptake in the putamen contralateral to the more affected limbs and normal D(2) receptor binding in the putamen. The PET and MRI findings and responsiveness to antiparkinsonian agents suggested degeneration of nigrostriatal dopaminergic neurons, striatal output pathways, and corticospinal tracts.

Adult↗
PubMed2002

Effect of dissolved oxygen conditions on nitrogen removal in continuously fed intermittent-aeration process with two tanks.

In this study, an intermittent aeration type activated sludge process that is fed continuously is evaluated for nitrogen and organic carbon for facilities in rural areas, which are characterized by small scale, low loading rate and automatic operation. Anoxic and aerobic conditions can be regulated alternatively by intermittent aeration for biological nitrogen removal. It is proved that an intermittent aeration cycle of 90 min, with aeration/anoxic mixing periods of 25-30 min/65-60 min in Tank 1, and 30-45 min/60-45 min in Tank 2, and a DO control set at 0.6-1 mg/L during the aeration period are required for satisfactory treatment performance. Under these conditions, a stable effluent water quality with BOD < or = 5 mg/L, CODMn < or = 8 mg/L, Nitrogen < or = 3 mgN/L, SS < or = 5 mg/L and transparency > or = 80 cm can be achieved. The solids retention time in aerobic condition was 10-25 d, which is sufficient for nitrification.

Agriculture↗
PubMed2002

Fishing for bioactive substances from scorpionfish and some sea urchins.

Venom proteins from the dorsal spine of two scorpionfish, Hypodytes rubripinnis and Synanceia verrucosa were assayed for mitogenicity and cytotoxicity. The two venoms had both mitogenic and cytotoxic activity on murine splenocytes and murine P388 leukemic cells. In H. rubripinnis, the second gel chromatographic fraction showed cytotoxic activity on P388 leukemic cells. On native PAGE, the glycoprotein isolated by concavalin A sepharose chromatography appeared to have a molecular mass of 110 kDa. In addition, two D-galactose-binding lectins (SUL-I and SUL-II) and a heparin-binding lectin (TGL-I) were purified from the globiferous pedicellariae of the toxopneustid sea urchins, Toxopneustes pileolus and Tripneustes gratilla, respectively. SUL-I (Nakagawa et al., 1999a) had mitogenic activity and cytotoxic activity but SUL-II and TGL-I did not. SUL-I did not show sequence homology to SUL-II. A hemolytic lectin with a molecular mass of 29 kDa was isolated from the coelomic fluid of T. gratilla. The hemolytic activity of the lectin was dependent on Ca2+ concentration and inhibited by lactose. The present results suggest that some species of scorpionfish and sea urchins may be novel sources for biologically active substances such as anti-tumor compounds or new lectins.

Agglutination↗
PubMed2001

Water exchange rates in the diruthenium mu-oxo ion cis,cis-[(bpy)(2)Ru(OH(2))](2)O(4+).

Addition of 2 equiv of Ce(4+) to the dimeric ruthenium mu-oxo ion cis,cis-[(bpy)(2)Ru(OH(2))](2)O(4+) (formal oxidation state III-III, subsequently denoted [3,3]) or addition of 1 equiv of Ce(4+) to the corresponding [3,4] ion gave near-quantitative conversion to the [4,4] ion, confirming our recent assignment of this oxidation state as an accumulating intermediate during water oxidation by the cis,cis-[(bpy)(2)Ru(O)](2)O(4+) ([5,5]) ion. The rates of water exchange at the cis-aqua positions in the [3,3] and [3,4] ions were investigated by incubating H(2)(18)O-enriched samples in normal water for predetermined times, then oxidizing them to the [5,5] state and measuring by resonance Raman (RR) spectroscopy changes in the magnitudes of the O-isotope sensitive bands at 780 and 818 cm(-1). These bands have been assigned to Ru=(18)O and Ru=(16)O stretching modes, respectively, for ruthenyl bonds formed by deprotonation of the aqua ligands upon oxidation to the [5,5] state. An intermediate accumulated during the course of the isotope exchange reaction that gave a [5,5] ion possessing both approximately 782 and approximately 812 cm(-1) bands; this spectrum was assigned to the mixed-isotope species, (bpy)(2)Ru((16)O)(16)ORu((18)O)(bpy)(2)(4+). Kinetic analysis of solutions at various levels of oxidation indicated that only the [3,3] ion underwent substitution; the exchange rate constant obtained in 0.5 M trifluoromethanesulfonic acid, 23 degrees C, was 7 x 10(-3) s(-1), which is (10(3)-10(5))-fold larger than rate constants measured for anation of monomeric (bpy)(2)Ru(III)X(H(2)O)(3+) ions bearing simple sigma-donor ligands (X).

2,2'-Dipyridyl↗
PubMed2001

Glycosaminoglycan accumulation in primary culture of rabbit intervertebral disc cells.

STUDY DESIGN: With the heterogeneity of the intervertebral disc as the focus, intervertebral discs from normal young rabbits were separated into nucleus pulposus (NP), inner anulus fibrosus (IAF), and outer anulus fibrosus (OAF) zones. Disc cells from each zone were isolated and propagated under monolayer and within agarose gel culture. The metabolism of these cultured disc cells was examined in terms of glycosaminoglycan (GAG) accumulation. OBJECTIVES: The object was to study the metabolism of disc cells derived from each zone and characterize them on the basis of GAG accumulation and composition. SUMMARY OF BACKGROUND DATA: It has been shown that three-dimensional culture systems, such as within-agarose gels or in alginate beads, permit long-term maintenance of the articular chondrocyte phenotype in vitro. However, little has been reported on how the metabolism of intervertebral disc cells, especially GAG accumulation, is affected by different culture conditions. METHODS: Cells from each zone were subjected to monolayer or three-dimensional culture for up to 12 days. GAG accumulation in the different culture systems was analyzed using chemical, histologic, and immunohistologic methods. Differences of GAG and DNA content among NP, IAF, and OAF cells were statistically evaluated by analysis of variance. The data of keratin sulfate content in three-dimensional culture were compared with that in monolayer culture using nonparametric Mann-Whitney U test. RESULTS: Monolayer culture revealed that increases in GAG content were significantly higher in IAF cells than in OAF cells. However, in three-dimensional culture GAG content was similar in the two groups. AF cells in three-dimensional cultures showed immunohistochemical localization of chondroitin sulfate and keratan sulfate, suggesting the existence of pericellular matrix. High performance liquid chromatography confirmed the expression of keratan sulfate in cultured cells. CONCLUSIONS: GAG accumulation in cultures of cells from different zones of the intervertebral disc varied according to the culture conditions used. The importance of choosing the appropriate culture systems to meet the objectives of a study should be emphasized.

Analysis of Variance↗
PubMed2001

Lumbar canal stenosis caused by hypertrophy of the posterior longitudinal ligament: case report.

STUDY DESIGN: This is a case report of a patient with hypertrophy of the posterior longitudinal ligament (HPLL) in the lumbar spine, with assessment of operative treatment and a 10-year follow-up using magnetic resonance imaging. OBJECTIVES: To report on the long-term outcome of a case of lumbar HPLL, to review the literature on case reports of HPLL, and to outline the pathology of HPLL in the lumbar spine. SUMMARY OF BACKGROUND DATA: There have been several reports of HPLL in the cervical spine and thoracic spine. However, the authors found no reports of this condition in the lumbar spine and no reports of long-term follow-up. Two types of pathology are associated with HPLL: primary hypertrophy of the ligament and secondary hypertrophy associated with intervertebral disc herniation. METHODS: A 10-year follow-up evaluation of a 56-year-old man with HPLL at L2 is reported. The patient was observed using serial physical examinations, radiographs, and MRIs over 10 years. Because he did not respond to conservative management, surgical treatment was applied. After complete decompression by hemilaminectomy and resection of hypertrophied ligament, the nerve roots were freed of constriction through the neural foramens at L2 and L3. RESULTS: One year after the operation the patient was asymptomatic without evidence of recurrence of the disease. CONCLUSIONS: HPLL is a very rare disease. This appears to be the first report of the disease in the lumbar spine.

Humans↗
PubMed2001

Nonneurogenic hypoxia sensitivity in rat adrenal slices.

A change in the intracellular Ca(2+) ([Ca(2+)](i)) level induced by hypoxia was detected in rat adrenal slices by use of fura-2/AM. After hypoxic stress, an increase in [Ca(2+)](i) was observed only in the adrenal medulla. This increase was inhibited by nifedipine, but not modified by the cholinergic receptor blockers. The hypoxia-induced increase in [Ca(2+)](i) was observed in all postnatal developmental stages to a similar extent, whereas the nicotine and high K(+) sensitivities increased along with postnatal development. A 10 nM ryanodine enhanced the hypoxia-induced [Ca(2+)](i) increase in adult but not in neonatal rat slices. These results suggest the existence of an oxygen-sensing mechanism in adult rat adrenals even after sympathetic innervation. Hypoxic responses seemed to be similar both in neonate and in adult rat adrenals and were triggered by the influx of Ca(2+) via L-type voltage-sensitive Ca(2+) channels. However, the sustained [Ca(2+)](i) increase caused by hypoxia might depend on postnatal development and be triggered by Ca(2+)-induced Ca(2+) release (CICR).

Adrenal Glands↗
PubMed2001

Determination of amino acid sequence responsible for suppression of bone resorption by serum calcium-decreasing factor (caldecrin).

We previously reported on the serum calcium-decreasing activity of recombinant protein factor referred to as caldecrin [Tomomura et al. (1995) J. Biol. Chem. 270, 30315-30321]. To address the mechanism of this serum calcium-decreasing activity, we investigated the effect of rat caldecrin on osteoclastic bone-resorbing activity. Wild-type caldecrin suppressed resorption pit formation by osteoclast on a dentine slice in a dose-dependent manner. The suppressive effect on the bone resorption was not affected by treatment of caldecrin with phenylmethyl sulfonyl fluoride or by use of protease-deficient mutant caldecrins. Recombinant procaldecrin (-13-239), and its fragments (-13-125), (1-111), (1-46), (47-111), and (126-239) were expressed as His-tagged thioredoxin fusion proteins and investigated for their ability to suppress bone resorption. The proform (-13-239) and fragment (-13-125) did not affect the suppressive activity, whereas fragments (1-111) and (126-239) did suppress the bone resorption. The bone-resorbing activity was also suppressed by fragment (47-111), not by fragment (1-46). Overlapping fragments (47-62), (47-79), (47-98), (56-111), (71-111), and (85-111) were compared for their suppressive activity. The fragments (47-62) and (85-111) did not affect the activity, but the other fragments suppressed the bone resorption. A synthetic peptide having the (71-79) sequence suppressed the bone resorption. These results suggest that amino acid sequence corresponding to rat caldecrin (aa 71-79) is responsible for the suppression of bone resorption by caldecrin.

Amino Acid Sequence↗