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O Kaneko

Publications and source records attributed to O Kaneko.

At least 37 records · Page 2Linked to original sources
PubMed1999

Search for the sialic acid-independent receptor on red blood cells for invasion by Plasmodium falciparum.

BACKGROUND AND OBJECTIVES: Plasmodium falciparum uses multiple red blood cell (RBC) receptors and parasite ligands to invade RBCs. One pathway uses a sialic acid-independent protein or carbohydrate for invasion. The present study searches for this RBC receptor. MATERIALS AND METHODS: We determined whether antigen-negative and null RBCs (including PNH cells that lack all glycosylphosphatidyl inositol-linked proteins) could be invaded after neuraminidase treatment. We used two P. falciparum clones for the study: one that requires sialic acid for invasion and was an indication of removal of sialic acid and a second clone that can invade neuraminidase-treated RBCs. RESULTS: All neuraminidase-treated variant RBCs in this study were invaded. CONCLUSION: This study indicates that some molecule other than those studied (e.g., a carbohydrate) is the receptor for the sialic acid-independent pathway. This powerful tool for the identification of receptors for microorganisms should be used more extensively.

Animals↗
PubMed1998

Do obesity and non-insulin dependent diabetes mellitus aggravate exercise-induced microproteinuria?

We evaluated the role of obesity in proteinuria by treadmill exercising of simple obese subjects and non-obese subjects with non-insulin dependent diabetes mellitus in whom the albumin excretion rate at rest was within normal range. Non-obese healthy volunteers were studied as the controls. The fractional renal clearances of four endogenous proteins, albumin, IgG, IgG4, and beta2-microglobulin were measured before, during, and after treadmill exercise in 17 simple obese and 15 non-obese diabetic subjects, and in 21 normal subjects. Exercise increased the fractional albumin clearance in all groups. In diabetic subjects, the fractional IgG4 clearance also increased: fractional beta2-microglobulin clearance increased in normal controls and in diabetics. In obese subjects, the fractional clearances of albumin, IgG, and IgG4 were similar to those in normal controls, but fractional beta2-microglobulin clearance was significantly lower. These results suggest that enhanced microalbuminuria in obese subjects is probably of glomerular origin. In normal subjects and diabetics, exercise-induced microproteinuria is probably of both glomerular and tubular origin. Defect in the charge-selective barrier of the glomerular capillary wall has been implicated in diabetics. Thus some additional factors relevant to obesity must be taken into account in the consideration of the mechanism of microalbuminuria in diabetics with obesity.

Adolescent↗
PubMed1998

Source of reactive oxygen species in anti-Thy1 nephritis.

In proliferative glomerulonephritis, both macrophages and mesangial cells generate reactive oxygen species (ROS), contributing to the development of glomerular injury. We have attempted to determine which cell produces ROS during anti-Thy1 nephritis (ATN) in rats. The generation of ROS was studied using luminol amplified chemiluminescence (GCL) on isolated glomeruli. Immunohistochemical studies used avidin-biotin complex (ABC) to label macrophages and mesangial cells. Immediately after ATN induction, mesangiolysis and infiltration with ED-1 positive cells (referred to as macrophage) was noted with a peak at day 1. After day 4, mesangial proliferation appeared with a decrease of the ED-1 positive cells and a prominent increase of PCNA positive cells (regarded as mesangial cells). In the early phase of ATN, GCL, reflecting ROS generation, increased along with the appearance of ED-1 positive cells. GCL subsequently decreased as mesangial cells increased. This suggested that macrophage were the principal participants in ROS generation in the early phase of ATN although mesangial cells cannot be completely disregarded in the generation of ROS and development of glomerular injury.

Animals↗
PubMed1998

Allelic diversity at the merozoite surface protein-1 locus of Plasmodium falciparum in clinical isolates from the southwestern Brazilian Amazon.

Nucleotide sequences of each variable block in the Plasmodium falciparum merozoite surface protein-1 gene (PfMSP-1) may be grouped into one of two or three possible allelic types, named after the reference isolates MAD20, K1, and RO33. Allelic diversity at this locus basically results from different combinations of allelic types in variable blocks. We used a polymerase chain reaction (PCR)-based strategy to type the variable blocks 2, 4a, 4b, and 10 of the PfMSP-1 gene of P. falciparum isolates from 54 symptomatic malaria patients living in Rondonia, a hypoendemic area in the southwestern Brazilian Amazon. Ten different PfMSP-1 gene types, defined as unique combinations of allelic types in variable blocks, were identified among the 54 isolates. Twenty-one isolates (39%) harbored more than one gene type and two had at least three genetically distinct clones. Hybrid sequences, with a MAD20-type sequence in the 5' segment (4a) and a K1-type sequence in the 3' segment (4b), were quite common in block 4. Direct sequencing of block 4 PCR products revealed a new putative recombination site in four isolates. In contrast with previous studies, the observed distribution of gene types does not deviate significantly from that expected under the null hypothesis of random association between allelic types detected in each variable block. These contradictory data are discussed with reference to the immunoepidemiologic features prevailing in distinct malaria-endemic areas.

Adolescent↗
PubMed1998

A PCR method for molecular epidemiology of Plasmodium falciparum Msp-1.

Merozoite surface protein-1 (MSP-1) of Plasmodium falciparum is a strong malaria vaccine candidate. However, MSP-1 exhibits extensive antigenic polymorphism, an issue which may compromise the development of effective vaccine based on this molecule. Since polymorphic nature of MSP-1 has not been fully understood in endemic areas of malaria, variation of the MSP-1 gene (Msp-1) must be studied in detail in natural parasite populations. Here, a PCR-based method for determination of P. falciparum Msp-1 haplotype is described, which can detect up to 24 different haplotypes per infected person. The method can be applied to various purposes of molecular epidemiology of not only Msp-1 haplotype but the genetic structure of P. falciparum populations.

Animals↗
PubMed1997

Plasmodium falciparum: allelic variation in the merozoite surface protein 1 gene in wild isolates from southern Vietnam.

Allelic variation in the Plasmodium falciparum merozoite surface protein 1 (MSP1) gene is expressed as an association of allelic types in variable blocks. In this study, a PCR strategy that can detect 24 different MSP1 association types was used to investigate allelic variation in the MSP1 gene. We identified 236 distinct association type clones in 136 wild isolates collected from southern Vietnam, analysis of which revealed that (1) recombination between two representative allelic types in the central part of the MSP1 gene did not exist, (2) frequency distribution of MSP1 association types did not differ in different population groups, and (3) particular MSP1 association types were predominant. Statistical analysis for the association of allelic types indicated significant, nonrandom associations between blocks 4 and 6 but not between blocks 2 and 4, and 2 and 6. These results suggest that selection operates in favor of particular MSP1 association types. In addition, direct sequencing of 31 isolates confirmed reported sequence substitutions in the C-terminal 19-kDa Cys-rich region of MSP1, supporting a notion of limited variations in this region, a strong vaccine candidate molecule.

Alleles↗
PubMed1997

Immunological suppression after surgery in scoliosis patients.

This is a prospective study to analyze the postoperative immunological changes in scoliosis surgery. Twenty-eight patients who underwent Harrington instrumentation were analyzed. Seven patients who underwent arthroscopic surgery were analyzed as a control group. The objective of this study is to determine whether surgery and surgical stress (minor versus major surgery) changed the immune capability of patients as indicated by the ratio of lymphocyte cell types and interferon induction. Pre- and postoperative blood from scoliosis and knee arthroscopy patients was analyzed at various times using antisera and two-color flow cytometry with monoclonal antibodies. Both scoliosis and knee arthroscopy patients had a postoperative decrease in the population of B-lymphocytes (Leu 12+) and a transient increase in the natural killer cells (Leu 4-/Leu 19+) and the cytotoxic T-lymphocytes (Leu 2a++/Leu 15-). These changes were significantly greater in the scoliosis patients, who also experienced a prolonged decrease in the inducer T-lymphocytes (Leu 8+/Leu 3a+) for 3 weeks following surgery. Production of interferon-alpha and interferon-gamma by lymphocytes was suppressed postoperatively and returned to preoperative levels within 3 weeks. Immunological depressive changes occurred postoperatively and lasted at least 1 week. These effects are more pronounced with longer surgeries, suggesting greater postoperative vigilance for infections in these cases.

Adolescent↗
PubMed1997

Ultrastructural background of albuminuria in rats with passive Heymann nephritis.

BACKGROUND: Although it is widely known that proteinuria in rats with passive Heymann nephritis (PHN) is prevented by treatment with cobra venom factor (CVF), the precise mechanisms of complement-dependent proteinuria have not been fully elucidated. The aim of this study was to evaluate morphologically whether the size of subepithelial electron-dense deposits (EDDs) contributes to the onset of albuminuria. METHODS: The size of subepithelial EDDs and anionic sites in the lamina rarae externa (LRE) overlaid with subepithelial EDDs were evaluated by ruthenium red and compared between PHN and PHN treated with CVF in rats. RESULTS: Overt albuminuria was present on days 3 and 4 after injection of anti-Fx1A. CVF-treatment of rats with PHN prevented albuminuria (PHN + CVF: n = 6) (53.6 +/- 38.8 vs 1.02 +/- 0.55 mg/day, P < 0.01, on day 4). Rat C3 was detected along the glomerular capillary walls on day 4 post-injection in rats with PHN, but not in rats with PHN + CVF. Subepithelial EDDs were observed in both groups. Quantitative morphometric analysis revealed that CVF-treatment decreased the size of subepithelial EDDs as well as the extent of retraction of glomerular epithelial cells. In both groups the density of anionic sites in the LRE overlaid with EDDs was decreased compared with the LRE without subepithelial EDDs. However, no difference was noted between the two groups. CONCLUSIONS: Depletion of serum complement decreases subepithelial EDDs as well as the number of sites with decreased anionic charge underlying the EDDs. Thus, the size of subepithelial EDDs plays a pivotal role in the onset of albuminuria.

Albuminuria↗
PubMed1996

Sequence variation in the 18S rRNA gene, a target for PCR-based malaria diagnosis, in Plasmodium ovale from southern Vietnam.

Field surveys of malaria were performed in southern Vietnam by using an acridine orange staining method for rapid diagnosis and a PCR-based, microtiter plate hybridization method for accurate diagnosis. A total of three patients of Plasmodium ovale infection were detected, but PCR-amplified DNA of the P. ovale isolates from two of the patients did not hybridize with the P. ovale-specific probe. Analysis of the target sequence in the 18S rRNA gene indicated that in the DNA of isolates from both patients three nucleotides in the probe region from the typical P. ovale sequence were different, with deletions of two nucleotides and the substitution of one nucleotide. These results may suggest that in addition to molecular biological methods, careful microscopic examination of stained thin blood films is still required in studies of the prevalence of different malaria species.

Animals↗
PubMed1990

[The arterial distribution to the abdominal digestive organs in human fetuses].

The arterial supply of the abdominal digestive organs and the developmental process were studied in 25 Japanese fetuses from 3 months to 9 months old into whose arteries latex rubber was injected. The results were as follows: 1) The branching patterns of the celiac trunk were classified into 5 types. The most common type or the complete celiac trunk was found in 18 cases (72%). Four variation types or incomplete celiac trunks were found in 7 cases (28%). 2) The rates at which the following arteries were observed in the stomach were as follows: 100% for the left gastric artery, 100% for the left and right gastroepiploic artery, 100% for the short gastric artery, 100% for the gastroduodenal artery, 92% for the right gastric artery, 24% for the branch of the left inferior phrenic artery, and 16% for the posterior gastric artery arising from the splenic artery. The left gastric artery was better developed than the other arteries in 3-month-old fetuses. 3) The rates at which the following arteries were observed in the liver were as follows: 100% for the proper hepatic artery, 28% for the accessory left hepatic artery and 8% for the accessory right hepatic arteries. The accessory left hepatic artery in 3-month-old fetuses was better developed than in older fetuses. 4) The rates at which the following arteries were observed in the pancreas were follows: 100% for the branches of the splenic artery, 100% for the branches of the gastroduodenal artery and 100% for the branches of the superior mesenteric artery. Further, dorsal pancreatic arteries not arising from the splenic artery were found in 20% of cases. The dorsal and great pancreatic arteries branching from the splenic artery could not be distinguished from one another in younger fetuses. 5) The rates at which the following arteries were observed in the duodenum were as follows: 100% for the branches of the superior and the inferior pancreaticoduodenal arteries. This arterial supply was the same in all the fetuses. 6) The arterial supply of the jejunum and the ileum were as follows: the jejunum and the ileum were supplied only by the branches of the superior mesenteric artery. The minimum number of the branches was 7 and the maximum 12. 7) The arterial supply of the large intestine was as follows: the caecum was supplied only by the ileocolic artery.(ABSTRACT TRUNCATED AT 400 WORDS)

Arteries↗