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Biomedical subjects

Y Harada

Publications and source records attributed to Y Harada.

At least 145 records · Page 8Linked to original sources
PubMed1999

Genetic diversity of HIV-1 group M from Cameroon and Republic of Congo.

We analyzed 57 HIV-1 isolates from Cameroon and the Republic of Congo, with respect to the env C2V3 and/or the pol integrase regions. The results indicated that the topology of the pol tree correlated well with that of the env tree for four clusters of subtype D, F G and H, suggesting that these trees reflect the true evolution of the overall genome structures of these subtypes. However, of 22 Cameroonian isolates that were classified as subtype A based on env, 20 of them diverged in their pol sequence into two lineages that were completely different from the prototypical subtype A, tentatively designated as subtypes A1 and A2. The subtype A1 isolates (6 out of 22) were related in their env C2V3 regions with prototypical subtype A strain, but in their pol regions, they formed an independent cluster that diverged from known HIV-1 subtypes so far reported (except for subtypes I and J). The subtype A2 isolates (14 out of 22), which represent the major epidemic type of HIV-1 in Cameroon, clustered distinctly in both the env and pol trees with the recently described A/G mosaic strains from Nigeria and Djibouti. These two lineages were not spreading in the neighboring Republic of Congo.

Amino Acid Sequence↗
PubMed1999

Effects of hyaluronan on periosteal grafts for large full-thickness defects in rabbit articular cartilage.

We studied the effects of hyaluronan (HA) on chondrogenesis in periosteal grafts in rabbit knees to elucidate the effects of this agent in the repair of articular cartilage. Large full-thickness defects of the articular cartilage were created in the anteromedial part of the femoral articular surface of bilateral knee joints. Periosteal grafts were then harvested and sutured onto the defects. HA was injected in the right knee immediately after the operation and then once a week for 4 weeks (HA group). The same volume of saline was injected in the left knee in the control group. The animals were killed 2, 5, 8, and 12 weeks after the operation. Macroscopic and histological findings of the regenerated tissue were evaluated with a semiquantitative histological grading system. The total histological scores of the HA group were better than those in the control group at each time examination point. At 12 weeks, in particular, the scores for surface regularity and integration to adjacent articular cartilage were significantly better in the HA group than in the control group (P < 0.05). No significant differences were observed between the two groups in regard to the area healed (%). HA may have beneficial effects on the repair of large full-thickness defects of the articular cartilage with autologous periosteal grafts.

Adjuvants, Immunologic↗
PubMed1999

Measurement of bone marrow blood volume in the knee by positron emission tomography.

Positron emission tomography was used to measure bone marrow blood volume (BBV), an important hemodynamics parameter, in the knee. The subjects were 11 healthy male volunteers (mean age, 23.6 years; range, 21-27 years). The 15O-labelled carbon monooxide (C15O) single-breath inhalation method was used. In the distal femur, regional (r) BBV in the posterior area of the epiphysis (medial, 2. 25 ml/100 cm3 bone marrow; lateral, 2.03 ml/100 cm3) was significantly less than that in the anterior area of the epiphysis (medial, 3.48 ml/100 cm3; lateral, 3.01 ml/100 cm3) and that in the metaphysis-to-distal diaphysis (2.90-3.67 ml/100 cm3). In the proximal tibia, rBBVs in the metaphysis-to-proximal diaphysis (2. 32-2.76 ml/100 cm3) were significantly less than those in the area of the physis (medial, 3.30 ml/100 cm3; lateral, 3.53 ml/100 cm3). These regional differences in rBBV within the knee may be associated with the development of ischemic bone marrow disorders, such as steroid-induced osteonecrosis, in the knee.

Adult↗
PubMed1999

Radial-sequence magnetic resonance imaging in evaluation of acetabular labrum.

We investigated the usefulness of a radial-sequence magnetic resonance imaging (MRI) technique in the visualization of the acetabular labrum, which surrounds the acetabulum. In 22 hip joints of 12 volunteers, T2-weighted images were obtained on 24 radial planes of the acetabular rim, set at 15 degrees -intervals, using the small tip angle gradient echo method. We examined 7 planes in the weight-bearing portion. The acetabular labrum in the weight-bearing portion was depicted in good contrast to the surrounding tissues. The shape of the labrum differed among individuals and also in the anterior and posterior portions of the labrum. The signal intensity of the labrum was low or partially moderate. There was a high signal intensity band on the base of the acetabular labrum in several portions, which should be carefully interpreted to avoid confusion with abnormality. We concluded that radial-sequence MRI could be a useful technique for evaluation of the condition of the acetabular labrum in the weight-bearing portion.

Acetabulum↗
PubMed1999

Complete cDNA sequence and genomic organization of a human pancreas-specific gene homologous to Caenorhabditis elegans sel-1.

We have isolated the complete cDNA of a human SEL-1L gene, termed TSA305, that is abundantly expressed only in the pancreas. The cDNA contained an open reading frame of 2382 nucleotides, encoding a deduced protein of 794 amino acids whose predicted sequence showed 46% identity and 64% similarity with SEL-1 of Caenorhabditis elegans. SEL-1 is thought to be a negative regulator of the NOTCH, LIN-12, and GLP-1 receptors, which are required for differentiation and maturation of cells as well as cell-cell interactions during development in C. elegans. The degree of homology among these proteins suggests that the TSA305 gene product may be a member of the SEL-1 family and therefore involved in downregulation of mammalian Notch signaling. Direct sequencing revealed at least 20 coding exons in TSA305. We localized the gene to chromosome bands 14q24.3-q31 by radiation hybrid (RH) mapping and fluorescence in situ hybridization (FISH). The IDDM11 locus has been mapped in this region, and TSA305 may represent a candidate gene for predisposition in some families whose insulin-dependent diabetes is not linked to the HLA locus.

Amino Acid Sequence↗
PubMed1999

Single-molecule imaging of RNA polymerase-DNA interactions in real time.

Using total internal reflection fluorescence microscopy, we have directly observed individual interactions of single RNA polymerase molecules with a single molecule of lambda-phage DNA suspended in solution by optical traps. The interactions of RNA polymerase molecules were not homogeneous along DNA. They dissociated slowly from the positions of the promoters and sequences common to promoters at a rate of approximately 0.66 s-1, which was more than severalfold smaller than the rate at other positions. The association rate constant for the slow dissociation sites was 9.2 x 10(2) bp-1 M-1 s-1. The frequency of binding to the fast dissociation sites was dependent on the A-T composition; it was larger in the AT-rich regions than in the GC-rich regions. RNA polymerase molecules on the fast dissociation sites underwent linear diffusion (sliding) along DNA. The binding to the slow dissociation sites was greatly enhanced when DNA was released to a relaxed state, suggesting that the binding depended on the strain exerted on the DNA. The present method is potentially applicable to the examination of a wide variety of protein-nucleic acid interactions, especially those involved in the process of transcription.

Bacteriophage lambda↗
PubMed1999

Expression and function of cyclooxygenase-2 in mesothelial cells during late phase of rat carrageenin-induced pleurisy.

We have previously shown that the inducible isoform of the cyclooxygenases, COX-2, is strongly expressed in pleural exudate leukocytes early (between 3 and 7 hr after irritation) during rat carrageenin-induced pleurisy. The present study further examined COX-2 expression and disclosed that mesothelial cells expressed COX-2 later (12 to 24 hr after irritation) in this model. A COX-2 inhibitor, nimesulide, lowered the intrapleural level of 6-keto-PGF1alpha and inhibited hyperplasia of the pleural matrix, suggesting that COX-2 expressed in mesothelial cells may play a role in the synthesis of extracellular matrix through formation of PGI2.

Animals↗
PubMed1999

Banding of the pulmonary trunk in preparation for a Fontan operation.

Banding of the pulmonary trunk is an important surgical procedure for patients who have congenital cardiac malformations with unrestricted pulmonary flow. We propose a new concept for determining in such circumstances the most appropriate length of the band used to constrict the pulmonary trunk in preparation for a Fontan operation. We studied 14 patients undergoing banding of the pulmonary trunk and measured the following parameters: diameter of aorta, diameter of pulmonary trunk, length of pulmonary arterial band and maximum flow velocity across the banded segment. We calculated an index from our original parameter based on the formula; length of band/(diameter of aorta diameter of pulmonary trunk). The diameter of aorta was 9.5 +/- 1.4 mm, and that of the pulmonary trunk was 9.6 +/- 2.3 mm. The length of the band was 16.5 +/- 3.4 mm, giving a calculated index of 0.188 +/- 0.038. The maximum flow velocity was 4.02 +/- 0.46 m/s. No correlation was found between the length of the band and body weight, and also no correlation was found between the length of the band and maximum flow velocity. The calculated index had a negative correlation with the maximum velocity of flow across the band (y = -8.13x +/- 5.56, R = 0.74, p < 0.01). We believe that the proposed index is a useful guide in determining the length of a pulmonary band when preparing patients for a Fontan operation.

Cardiac Catheterization↗
PubMed1999

Effect of Na+/Ca2+ exchange inhibitor, KB-R7943 on ouabain-induced arrhythmias in guinea-pigs.

1. We investigated protective effects of KB-R7943, a Na+/Ca2+ exchange (NCX) inhibitor, on ouabain-induced tonotropy and arrhythmias in isolated whole atria and ouabain-induced changes in electrocardiogram (ECG) in the guinea-pig. 2. KB-R7943 (10 and 30 microM) suppressed the tonotropic effect of ouabain, and prolonged the onset time of extra-systole induced by ouabain in isolated atria. 3. The intravenous injection of KB-R7943 (1 and 3 mg kg-1) significantly increased the doses of ouabain required to induce ventricular premature beats (VPB), ventricular tachycardia (VT), ventricular fibrillation (VF) and cardiac arrest (CA) in anaesthetized guinea-pigs. 4. Lidocaine (Na+channel inhibitor) and R56865 (Na+ and Ca2+ overload inhibitor) also suppressed the ouabain-induced tonotropic effect and extra-systole in isolated atria, but Hoe-694 (Na+/H+ exchange inhibitor) or diltiazem (Ca2+ channel inhibitor) did not affect them. 5. Lidocaine also increased the doses of ouabain required to induce VPB, VT, VF and CA in anaesthetized guinea-pigs. 6. From these results, we conclude that KB-R7943 suppresses ouabain-induced arrhythmias through inhibition of the reverse-mode NCX.

Animals↗
PubMed1999

Cholestatic jaundice in two patients with primary amyloidosis: ultrastructural findings of the liver.

Two patients with primary amyloidosis (amyloid light chain case) and severe cholestatic jaundice are described. Liver biopsy in the preterminal stage demonstrated amyloid deposits in the perisinusoidal space and in portal tracts, and hepatocytes were atrophic because of compression by amyloid fibrils. Ultrastructural findings showed amyloid fibrils not only in Disse's space but also in the sinusoids, and the hepatocyte microvilli facing the amyloid fibrils were spicular. There were aggregates of lysosomal granules in the vicinity of bile canaliculi and some bile canaliculi were dilated with loss of microvilli. Amyloid fibrils in the portal tract compressed bile ductules, causing wide intercellular space and separated basement membranes from their epitheliums. These findings suggested disturbance in transporting not only of essential materials from sinusoids to hepatocytes but also of secretory vesicles into bile canaliculi and leakage of bile juice from small bile ductules in preterminal stage of primary amyloidosis.

Aged↗
PubMed1999

Effect of long-term ethanol consumption on ability to produce cytokine-induced neutrophil chemoattractant-1 in the rat liver and its gender difference.

Gut-derived lipopolysaccharide (LPS) may contribute to hepatocellular necrosis in alcoholic hepatitis through neutrophil sequestration in hepatic sinusoids. It is well known that the female has a greater susceptibility to alcoholic liver injury than the male. The aim of the present study was to investigate the effect of long-term ethanol consumption on ability of the liver to produce cytokine-induced neutrophil chemoattractant-1 (CINC-1), the most potent neutrophil-chemokine in rats, after LPS administration. Furthermore, we aimed to evaluate the gender difference in this ability. Male and female rats were pair-fed a liquid diet containing 36% of the total calories as ethanol or dextrose for 6 to 8 weeks. They were given LPS intravenously, and chemokine mRNA expression in the liver was evaluated after 2 and 6 hr. To study the organ or chemokine specificity, CINC-1 mRNA expression in the spleen and monocyte chemoattractant protein (MCP)-1 mRNA level were also determined. Serum ALT activity started to increase between 2 and 6 hr. Female rats fed an ethanol diet showed significantly higher ALT activity 6 hr after LPS injection than the male rats. CINC-1 mRNA expressions in the liver after 2 and 6 hr were significantly higher in the ethanol-fed group, compared with the pair-fed control. Female rats fed an ethanol diet showed a significantly higher level of CINC-1 mRNA in the liver than the male rats 2 hr after LPS injection. CINC-1 levels in the liver homogenates paralleled closely its mRNA expression, whereas its concentrations in sera did not correlate with those in the liver. Neither CINC-1 mRNA expression in the spleen nor MCP-1 mRNA expression in the liver was affected by ethanol feeding or gender. An additional experiment using the gonadectomized rats fed an ethanol diet showed that gonadectomy totally abolished the gender difference in CINC-1 mRNA of the liver. We conclude that CINC-1 induction in the liver may be responsible for LPS-induced hepatitis in the ethanol-fed rats, and that the difference in ability to produce CINC-1 between males and females is one important factor that may partly account for the gender difference of alcoholic liver disease.

Alcoholism↗
PubMed1999

Human immunodeficiency virus type 1 intergroup (M/O) recombination in cameroon.

Here we describe, for the first time, recombinants between two highly divergent major groups of human immunodeficiency virus type 1 (HIV-1), M and O, within a Cameroonian woman infected with three different HIV-1 strains, a group O virus, a subtype D virus, and a recently reported IBNG (A/G)-like recombinant virus. Using nested extra-long PCR amplification, we sequenced from the pol region to the env region including accessory genes of the viral genome obtained from the patient's uncultured peripheral blood mononuclear cells and examined the phylogenetic position of each gene. Compared with sequential blood samples obtained in 1995 and 1996, there were multiple segmental exchanges between three HIV-1 strains (O, D, and IBNG) and all the recombinants appeared to be derived from a common M/O ancestor. Importantly, recombination between groups M and O occurred, even though the homology between these two groups is 69, 76, 68, and 55% in the gag, pol, vif-vpr, and env regions, respectively. Recombination between strains with such distant lineages may contribute substantially to generating new HIV-1 variants.

Adult↗
PubMed1999

HERF1, a novel hematopoiesis-specific RING finger protein, is required for terminal differentiation of erythroid cells.

The AML1/core binding factor beta (CBFbeta) transcription factor is essential for definitive hematopoiesis; however, the downstream pathways through which it functions remain incompletely defined. Using a differential cloning approach to define components of this pathway, we have identified a novel gene designated HERF1 (for hematopoietic RING finger 1), whose expression during development is dependent on the presence of functional AML1/CBFbeta. HERF1 contains a tripartite RING finger-B box-alpha-helical coiled-coil domain and a C-terminal region homologous to the ret proto-oncogene-encoded finger protein. Expression of HERF1 during embryogenesis coincides with the appearance of definitive erythropoiesis and in adult mice is restricted to erythroid cells, increasing 30-fold during terminal differentiation. Importantly, inhibition of HERF1 expression blocked terminal erythroid differentiation of the murine erythroleukemia cell line MEL, whereas its overexpression induced erythroid maturation. These results suggest an important role for this protein in erythropoiesis.

Animals↗
PubMed1999

Clinical study of brain metastasis of renal cell carcinoma.

OBJECTIVES: To evaluate the natural history and the efficacy of treatments for renal cell carcinoma (RCC) with brain metastasis, we reviewed 18 patients with this disease. METHODS: Out of 325 cases with RCC treated at Osaka University Hospital from 1957 to 1993, 18 (5.5%, male:female ratio 16:2) cases developed brain metastases. Median follow-up was 44 months after the initial treatment of the primary lesion. Twelve patients had surgical resection of brain metastases (surgical group), and 7 of them received adjuvant radiotherapy. Six patients with poor performance status were treated with supportive therapy alone (nonsurgical group). RESULTS: Of 18 RCC patients with brain metastasis, 16 were male and 2 female. All brain metastases except for 1 case were symptomatic. Median interval between the initial treatment of the primary lesion and the diagnosis of brain metastasis was 19 months. The most frequent metastatic site prior to brain was the lung, which was detected in 7 cases (38.9%). Median survival of the entire group, measured from the onset of brain metastasis, was 9.5 months. One-year survival rate after the diagnosis of brain metastasis was 43.2% (64.8% in surgical group, 0% in nonsurgical group), 3-year 18.5% and 5-year 0%. Among 109 metastatic RCC, 14 patients were treated by lymphokine-activated killer (LAK) therapy. Out of 14 metastatic RCC patients treated by LAK therapy, 3 (21.4%) developed brain metastases. On the other hand, out of 95 metastatic RCC patients without LAK therapy, 15 (15.8%) had brain metastases. There was no significant difference in the rate of brain metastases between these two groups. CONCLUSION: There was a trend for prognosis of the surgical group to be better compared to that of the nonsurgical group, although it is not statistically significant. The optimum treatment for brain metastasis of RCC remains undefined, but our data suggested surgical resection in selected patients might contribute to prolonged survival of patients with brain metastasis. LAK therapy was not necessarily the risk factor of the brain metastasis.

Adult↗
PubMed1999

Effect of magnesium deficiency on autonomic circulatory regulation in conscious rats.

A close relationship between magnesium and cardiovascular function has been reported; however, the effect of magnesium deficiency on autonomic cardiovascular regulation has not been clarified. We investigated the effect of magnesium deficiency on the autonomic regulation of oscillations of the R-R interval, arterial blood pressure (BP), and renal sympathetic nerve activity (RSNA) by using the maximum entropy method in conscious rats. Its effect on baroreflex control of RSNA and heart rate were also investigated with a logistic function curve. Mean BP in magnesium-deficient rats was higher than that in control rats (mean+/-SE, 114.0+/-4.3 versus 101.6+/-3.4 mm Hg; P<0.05), and urinary excretion of catecholamine was increased by 2.4-fold. The fraction of low-frequency oscillation of RSNA was reduced (31.7+/-0.9% versus 36.2+/-1.5%, P<0.05) and the correlation between low-frequency oscillations of BP and RSNA was weakened in magnesium-deficient rats. There was no difference in high-frequency oscillation of the R-R interval, which is related to vagal tone, whereas sympathetic tone became dominant (square root of low-frequency/high-frequency ratio of R-R interval, 1.00+/-0.05 versus 0.67+/-0.05, P<0.0001) in magnesium-deficient rats. The maximal gain in the BP-RSNA relation tended to be reduced in magnesium-deficient rats (-7.7+/-1.1% versus -12.2+/-1.9%/mm Hg, P=0. 07); however, that in the BP-heart rate relation was increased (-8. 1+/-0.7 versus -4.5+/-0.5 bpm/mm Hg, P<0.01). These results suggest that magnesium deficiency induces sympathetic excitation, which results in hypertension but attenuates the baroreflex-related response of sympathetic nerves, whereas magnesium deficiency enhances the sensitivity of the sinus node to autonomic regulation.

Animals↗
PubMed1999

A case of aortitis syndrome and IgA nephropathy: possible role of human leukocyte antigens in both diseases.

A 51-year-old woman, who had both aortitis syndrome (Takayasu arteritis) and IgA nephropathy, presented with hypertension, fever, a high erythrocyte sedimentation rate, high C-reactive protein and serum IgG levels, proteinuria, and renal dysfunction. Renal arteriography showed stenosis and poststenotic dilatation at the origin of the right renal artery, as well as tortuosity of the left renal artery branches and marked atrophy of the left kidney. Renal biopsy showed IgA nephropathy with deposits of IgA, C3, and fibrinogen in the glomeruli and arteriolosclerosis. The present patient had human leukocyte antigen (HLA)-B 52, which is reported to be related to the aortitis syndrome, as well as HLA-DR 4, which is possibly related to IgA nephropathy, suggesting that HLA status may be involved in the pathogenesis of both diseases.

Adult↗