Biomedical subjects

H Fujioka

Publications and source records attributed to H Fujioka.

At least 37 records · Page 2Linked to original sources

PubMed2002

Conventional multiple or microdissection testicular sperm extraction: a comparative study.

BACKGROUND: Testicular sperm extraction (TESE) with ICSI is becoming the first-line treatment for non-obstructive azoospermia (NOA). Recently, the sperm retrieval rate (SRR) by microdissection TESE was reported to be higher than by conventional TESE. However, a comprehensive comparison between multiple and microdissection TESE patients including histological findings has not been reported. METHODS: Patients with NOA who underwent microdissection TESE (n = 56) or multiple TESE (n = 37) were compared. Pre-operative characteristics were similar between groups. In addition, microscopic findings during microdissection TESE also were investigated. RESULTS: Operative time was significantly longer for microdissection TESE than for multiple TESE. Histological examination suggested that spermatogenesis was relatively more impaired in the microdissection TESE group than in the multiple TESE group. Despite this, SRR by microdissection TESE (42.9%) appeared higher than by conventional TESE (35.1%) although this observation failed to reach statistical significance. Seventeen of 26 patients (65.4%) with heterogeneous tubule were successful for sperm retrieval. No severe operative complications occurred in any patient in either group, and no patient required post-operative hormone replacement to treat hypogonadism. CONCLUSIONS: Microsurgical technique is safe and may improve SRR for TESE in a variety of patients with NOA, especially patients with heterogeneous testicular tubules.

Adult↗

PubMed2001

Remarkable effect of aluminum reagents on rearrangements of epoxy acylates via stable cation intermediates and its application to the synthesis of (S)-(+)-sporochnol A.

A remarkable effect of (C(6)F(5)O)(3)Al for promoting the rearrangement of epoxy acylates via stable cation intermediates was found, and new methods for constructing chiral benzylic, vinylic, and acetylenic quaternary carbon centers were developed. During the study, the importance of the ionic nature of the O-metal bond in the intermediates of such epoxides was addressed. This method was applied to the asymmetric total synthesis of (S)-(+)-sporochnol A.

Alkenes↗

PubMed2001

Evolution of a unique Plasmodium falciparum chloroquine-resistance phenotype in association with pfcrt polymorphism in Papua New Guinea and South America.

The mechanistic basis for chloroquine resistance (CQR) in Plasmodium falciparum recently has been linked to the polymorphic gene pfcrt. Alleles associated with CQR in natural parasite isolates harbor threonine (T), as opposed to lysine (K) at amino acid 76. P. falciparum CQR strains of African and Southeast Asian origin carry pfcrt alleles encoding an amino acid haplotype of CVIET (residues 72-76), whereas most South American CQR strains studied carry an allele encoding an SVMNT haplotype; chloroquine-sensitive strains from malarious regions around the world carry a CVMNK haplotype. Upon investigating the origin of pfcrt alleles in Papua New Guinean (PNG) P. falciparum we found either the chloroquine-sensitive-associated CVMNK or CQR-associated SVMNT haplotypes previously seen in Brazilian isolates. Remarkably we did not find the CVIET haplotype observed in CQR strains from Southeast Asian regions more proximal to PNG. Further we found a previously undescribed CQR phenotype to be associated with the SVMNT haplotype from PNG and South America. This CQR phenotype is significantly less responsive to verapamil chemosensitization compared with the effect associated with the CVIET haplotype. Consistent with this, we observed that verapamil treatment of P. falciparum isolates carrying pfcrt SVMNT is associated with an attenuated increase in digestive vacuole pH relative to CVIET pfcrt-carrying isolates. These data suggest a key role for pH-dependent changes in hematin receptor concentration in the P. falciparum CQR mechanism. Our findings also suggest that P. falciparum CQR has arisen through multiple evolutionary pathways associated with pfcrt K76T.

ATP-Binding Cassette Transporters↗

PubMed2001

Relatively selective neuronal nitric oxide synthase inhibition by 7-nitroindazole in monkey isolated cerebral arteries.

The selectivity of 7-nitroindazole in inhibiting endothelial and neuronal nitric oxide synthases (eNOS and nNOS) was investigated by comparing its inhibitory action on relaxations mediated by nitric oxide (NO) in response to stimulation of perivascular nerves and in response to histamine in monkey cerebral artery strips. 7-Nitroindazole at 2 x 10(-5) M moderately attenuated the response to transmural electrical stimulation and to nicotine, but did to alter the endothelium-dependent relaxation in response to histamine in cimetidine-treated strips. Raising the concentration of 7-nitroindazole to 10(-4) M abolished the neurogenic response, partially inhibited the histamine-induced relaxation, but did not affect the response to NO. It is concluded that 7-nitroindazole is a relatively selective nNOS inhibitor; however, at high concentrations, it inhibits eNOS in monkey cerebral arteries.

Animals↗

PubMed2001

Stage-dependent localization of a novel gene product of the malaria parasite, Plasmodium falciparum.

A novel Plasmodium falciparum gene, MB2, was identified by screening a sporozoite cDNA library with the serum of a human volunteer protected experimentally by the bites of P. falciparum-infected and irradiated mosquitoes. The single-exon, single-copy MB2 gene is predicted to encode a protein with an M(r) of 187,000. The MB2 protein has an amino-terminal basic domain, a central acidic domain, and a carboxyl-terminal domain with similarity to the GTP-binding domain of the prokaryotic translation initiation factor 2. MB2 is expressed in sporozoites, the liver, and blood-stage parasites and gametocytes. The MB2 protein is distributed as a approximately 120-kDa moiety on the surface of sporozoites and is imported into the nucleus of blood-stage parasites as a approximately 66-kDa species. Proteolytic processing is favored as the mechanism regulating the distinct subcellular localization of the MB2 protein. This differential localization provides multiple opportunities to exploit the MB2 gene product as a vaccine or therapeutic target.

Amino Acid Sequence↗

PubMed2001

Modifications by sumatriptan and acetylcholine of nitric oxide-mediated neurogenic dilatation in dog cerebral arteries.

Canine cerebral arterial strips denuded of endothelium responded to nicotine and transmural electrical stimulation with relaxations, which were abolished by NG-nitro-L-arginine and methylene blue. Magnitudes of relaxation did not differ in the arteries contracted with prostaglandin F2alpha and sumatriptan, an effective therapeutic of migraine. Sumatriptan concentration-dependently contracted the arteries responding to 2 Hz stimulation with persistent relaxations, and the concentration of this 5-HT1B/1D/1F receptor agonist to overcome the relaxation averaged 1.06 x 10(-7) M. Acetylcholine inhibited the response to nerve stimulation due possibly to its action on prejunctional nitroxidergic nerves; the inhibition did not differ in the arteries contracted with prostaglandin F2alpha and K+. It appears that sumatriptan does not interfere with the release of nitric oxide from nerves but counteracts the neurogenic relaxation by functional antagonistic action on smooth muscle. Prejunctional inhibition by muscarinic receptor activation is unlikely associated with opening of neuronal K+ channels.

Acetylcholine↗

PubMed2001

Mitochondrial abnormalities in Alzheimer's disease.

The finding that oxidative damage, including that to nucleic acids, in Alzheimer's disease is primarily limited to the cytoplasm of susceptible neuronal populations suggests that mitochondrial abnormalities might be part of the spectrum of chronic oxidative stress of Alzheimer's disease. In this study, we used in situ hybridization to mitochondrial DNA (mtDNA), immunocytochemistry of cytochrome oxidase, and morphometry of electron micrographs of biopsy specimens to determine whether there are mitochondrial abnormalities in Alzheimer's disease and their relationship to oxidative damage marked by 8-hydroxyguanosine and nitrotyrosine. We found that the same neurons showing increased oxidative damage in Alzheimer's disease have a striking and significant increase in mtDNA and cytochrome oxidase. Surprisingly, much of the mtDNA and cytochrome oxidase is found in the neuronal cytoplasm and in the case of mtDNA, the vacuoles associated with lipofuscin. Morphometric analysis showed that mitochondria are significantly reduced in Alzheimer's disease. The relationship shown here between the site and extent of mitochondrial abnormalities and oxidative damage suggests an intimate and early association between these features in Alzheimer's disease.

Adolescent↗

PubMed2001

Enantioselective total synthesis of a potent antitumor antibiotic, fredericamycin A.

The asymmetric total synthesis of both enantiomers of the potent antitumor antibiotic fredericamycin A (1) is detailed based on the protocol for the construction of its peri-hydroxy polyaromatic skeleton bearing the chirality at the spiro carbon via a strong base-induced cycloaddition of suitably substituted homophthalic anhydrides (AB-ring unit) with an optically active CDEF-ring unit. Particular attention has been given to the novel synthesis of the optically active spiro carbon center by a stereospecific rearrangement of optically active benzofuzed-trans-epoxy acylates leading to spirocyclopentane-1,1'-indane systems. This method is quite useful for the construction of an optically active spiro compound and was applied to the synthesis of the optically pure CDEF-ring unit of 1. Cycloaddition of the optically pure CDEF-ring unit to AB-ring units prepared via benzyne afforded two natural and unnatural-type hexacyclic compounds, which were converted to natural and unnatural enantiomers of synthetic 1, and the absolute configuration of natural 1 was determined as S.

Antibiotics, Antineoplastic↗

PubMed2001

Fermi surface nesting and structural transition on a metal surface: In /Cu(001).

Peierls-type instability and structural phase transition are shown to occur on the surface of a normal metal. An In overlayer on Cu(001) undergoes a reversible transition at approximately 350 K. Scanning tunneling microscopy of the low-temperature, reduced-symmetry phase indicates a strong periodic lattice distortion (PLD). Angle-resolved photoemission of the high-temperature phase reveals that the In-derived surface resonance constitutes a square-shaped, quasi-two-dimensional Fermi surface within the projected bulk Cu bands. The Fermi surface exhibits one-dimensional nesting upon the transition, which is in agreement with the PLD periodicity.

Journal Article↗

PubMed2001

Induction of granulin precursor gene expression by estrogen treatment in neonatal rat hypothalamus.

Our previous research has demonstrated that androgen treatment during the perinatal period increases granulin (grn) precursor mRNA levels in the neonatal rat hypothalamus. To elucidate whether exogenous estrogen increases grn mRNA in the neonatal hypothalami, expression of grn gene in the neonatal hypothalamus was studied by the competitive reverse transcription-polymerase chain reaction method. At 6 and 10 days of age, grn gene expression was significantly increased in the hypothalamus of pups whose dam has been dietarily administrated ethinyl estradiol from day 15 of gestation to the day of sampling. The subcutaneous injection of estradiol benzoate to neonatal rats at 2 days of age significantly increased grn gene expression on day 10. It was shown that estrogen, as well as androgen, was able to induce grn gene expression in the neonatal hypothalamus.

Administration, Oral↗

PubMed2001

Clinical characteristics of acute pulmonary thromboembolism in Japan: results of a multicenter registry in the Japanese Society of Pulmonary Embolism Research.

BACKGROUND: Although the incidence of acute pulmonary thromboembolism (APTE) has been increasing in Japan, patient characteristics, management strategies, and outcome have not yet been assessed in large series. HYPOTHESIS: The present study was designed to investigate the current status of APTE in Japan. METHODS: Of a total of 533 registry patients with pulmonary thromboembolism, 309 with APTE were analyzed with respect to clinical symptoms and signs, predisposing factors, diagnostic procedures, estimation of deep venous thrombosis, treatment, and clinical course. RESULTS: Main risk factors were recent major surgery, cancer, prolonged immobilization, and obesity; only a few patients had coagulopathy and 36% were in cardiogenic shock at presentation. The majority of registry patients underwent lung scans or pulmonary angiography; 30% were diagnosed only by lung scanning. Venous ultrasonography was used in only 34 patients, while 188 patients underwent at least one diagnostic procedure for deep venous thrombosis. Thrombolysis was more frequently performed in patients with cardiogenic shock, and only a few patients received thromboembolectomy. In-hospital mortality rate was 14%. In patients with cardiogenic shock, the mortality rate was reduced by thrombolysis. The predictors of in-hospital mortality were male gender, cardiogenic shock, cancer, and prolonged immobilization. CONCLUSIONS: The patients in this registry had almost the same findings as those in Western patients, except for some points that had the possibility of demonstrating a difference between Westerners and Japanese in the development of APTE. These results can prove especially helpful in planning prospective, randomized trials that will clarify the impact of widely used treatment modalities on the outcome of patients with APTE.

Age Distribution↗

PubMed2001

A Plasmodium falciparum protein located in Maurer's clefts underneath knobs and protein localization in association with Rhop-3 and SERA in the intracellular network of infected erythrocytes.

We report on the characterization of monoclonal antibodies against Plasmodium falciparum schizonts, which recognize parasite proteins of 130 kDa and 20 kDa. The 130-kDa protein was released by alkaline sodium carbonate treatment, suggesting that the protein is a peripheral membrane protein, while the 20-kDa protein remained associated with the membranes following alkali treatment, suggesting it may be an integral membrane protein. Both proteins were localized to large cytoplasmic vesicles within the cytoplasm of trophozoite and schizont-infected erythrocytes by immunofluorescence assay and confocal microscopy. Both proteins colocalized with Bodipy-ceramide in trophozoite and immature schizont-infected erythrocytes, but not in segmenters. The 130-kDa protein was localized by immunoelectron microscopy (IEM) to Maurer's clefts underneath knobs in a knobby and cytoadherent (K +/ C+) P. falciparum strain. No IEM reactivity was obtained in a knobless and non-cytoadherent (K-/C-)

Animals↗

PubMed2001

Reproducibility of the brain perfusion index for measuring cerebral blood flow using technetium-99m compounds.

We previously developed an alternative method for estimating the brain perfusion index (BPI) using technetium-99m compounds and spectral analysis (SA) for quantification of cerebral blood flow (CBF). In this study, we investigated the reproducibility of the BPI values obtained by SA (BPIS) using a double injection of technetium-99m ethyl cysteinate dimer without any intervention, and compared it with that of the BPI values obtained by graphical analysis (BPIG). The BPIS values in the first (x) and second sessions (y) correlated closely (y=0.921x+0.036; r=0.962; n=64; s.e.e.=0.058 min-1). Although the BPIG values in the first (x) and second sessions (y) also correlated (y=0.942x+0.040; r=0.916; n=64; s.e.e.=0.061 min-1), the correlation coefficient for BPIS was significantly higher than that for BPIG. The reproducibility was dependent on the injection dose ratio of the second session to the first (R). The difference in BPI between the first and second sessions tended to be smaller when 1.5<R<2.5 than when 0<R<1.5 or 2.5<R. These results suggest that the reproducibility of BPIS is satisfactory and that it can be applied to two sequential measurements of CBF using a double injection of 99mTc compounds. When applying our method to such measurements, it is recommended that R is taken as approximately 2.0.

Aged↗

PubMed2001

Connatal tuberculosis in an extremely low birth weight infant: case report and management of exposure to tuberculosis in a neonatal intensive care unit.

UNLABELLED: A case of connatal tuberculosis in an extremely low birth weight infant is reported. The patient was a female with a birth weight of 973 g born in the 27th week of pregnancy. She developed respiratory distress and signs of infection immediately after birth, which did not respond to mechanical ventilation, antibiotics, and corticosteroid therapy. Connatal tuberculosis was confirmed at 48 days of age by isolation of Mycobacterium tuberculosis from the infant's tracheal aspirate and the mother's menstrual discharge. The infant died of respiratory failure at 90 days of age. Mantoux tuberculin skin tests (TST) were performed on 99 infants, 144 medical staff members, and two family members. TST conversion occurred in three medical staff members, and preventive therapy with isoniazid was initiated. Eight exposed infants had normal chest X-rays and negative gastric aspirates for acid-fast bacilli and all received preventive isoniazid therapy. No case of tuberculosis developed during the 2-year follow-up period. CONCLUSION: Connatal tuberculosis should be considered in neonatal respiratory infection resistant to antibiotics. Prevention of transmission of tuberculosis on the neonatal intensive care unit by chemoprophylaxis is important.

Antitubercular Agents↗

PubMed2001

Confinement of surface state electrons on Cu and Au field emitters.

Field-emission images of clean Cu and Au emitters show a peculiar halo-like ring centered at the [1 1 1] pole. Typical diameter and width of the ring are approximately 10 nm and approximately 2 nm, respectively. Since we found no geometrical features around the [1 1 1] pole that gives rise to such a ring pattern, we interpreted the ring pattern as representing enhanced emission from an annular terrace that resonantly confines surface electrons. A simple analysis shows that the observed ring pattern appears at a terrace whose width nearly matches the confinement condition.

Journal Article↗

PubMed2001

Ginsenoside potentiates NO-mediated neurogenic vasodilatation of monkey cerebral arteries.

The aqueous extract of the Panax ginseng (GE) potentiated the relaxation induced by transmural electrical stimulation or nicotine in monkey cerebral arterial strips denuded of the endothelium and partially contracted with prostaglandin F(2 alpha). The response to electrical stimulation was abolished by tetrodotoxin, whereas that to nicotine was suppressed by hexamethonium. N(G)-nitro-L-arginine abolished both of the neurogenic relaxation. Atropine did not alter the potentiating effect of GE. Relaxations induced by exogenous NO were unaffected by GE. The enhancement by GE, of the neurogenic response, appears to be associated with increment in the synthesis or release of NO from the perivascular nerve. Blockade of muscarinic prejunctional inhibition, superoxide scavenging action and phosphodiesterase inhibition are not involved.

Animals↗

PubMed2001

Molecular characterisation of glutamate dehydrogenase gene defects in Japanese patients with congenital hyperinsulinism/hyperammonaemia.

Congenital hyperinsulinism and hyperammonaemia (CHH) is caused by dysregulation of glutamate dehydrogenase (GDH). We characterised the GDH gene in two Japanese patients with CHH. Patient 1 showed late-onset and mild hypoglycaemic episodes and mild hyperammonaemia, compared with patient 2. In GDH activity of lymphoblasts, patient 1 showed twofold higher basal GDH activity than control subjects and mild insensitivity for GTP inhibition. Patient 2 showed severe insensitivity for GTP inhibition, and similar allosteric stimulation by ADP in the controls. Genetic studies identified heterozygous and de novo L413V and G446D mutations in patients 1 and 2, respectively. COS cell expression study confirmed that both mutations were disease-causing gene. The insensitivity for GTP inhibition in L413V and G446D was emphasised in COS cell expression system as a result of the dosage effect of mutant GDH gene. L413V showed less impairment of GDH than G446D based on biochemical and genetic results, which was consistent with the clinical phenotype. Based on the structure of bovine GDH, G446D was located in GTP binding site of pivot helix and its surroundings, while L413V was located in alpha-helix of antenna-like structure. These different locations of mutations gave different effects on GDH enzyme. The antenna-like structure plays an important role in GDH activity.

Animals↗

PubMed2001

Histologic analysis of the implanted cartilage in an exact-fit osteochondral transplantation model.

PURPOSE: Osteochondral transplantation is one of the useful treatments for articular cartilage defect. However, the histologic change of the implanted cartilage has not been reported in detail. We investigated the histology of exact-fit osteochondral transplants used to repair articular cartilage defects in an animal model. TYPE OF STUDY: This was a nonrandomized control study using an animal model. METHODS: Sixteen skeletally mature female Japanese white rabbits were used in the study. The region of the femoral groove was selected as the site for the osteochondral defect. A full-thickness cylindrical defect (7 mm in diameter and 7 mm in depth) through the articular cartilage and into the subchondral bone was made using the Osteochondral Autograft Transfer System (Arthrex, Naples, FL). The entire osteochondral fragment was removed and then returned to its original site in the femoral condyle precisely. Thus, the defect was repaired with an autogenous osteochondral transplantation of exactly the same size and configuration as the defect. Specimens were obtained 2, 4, 12, and 24 weeks postoperatively and were analyzed both macroscopically and histologically. RESULTS: Macroscopically, there was smooth continuity of the articular surface and the integration of the graft to the normal host cartilage. However, histologic examination showed that the layer of the grafted cartilage was thicker than that of the normal host cartilage and the extracellular matrix of the implanted cartilage exhibited a stronger staining pattern with safranin-O fast green than the normal cartilage. Cell density was higher in the grafted cartilage, particularly in the middle and the deep zones. Round and polygonal hypertrophic clusters of chondrocytes were observed in the middle and deep zones of the grafted cartilage. CONCLUSIONS: The histologic properties of the exact-fit implanted cartilage were different from that of normal articular cartilage. Further investigation of mechanical and structural properties of grafted cartilage is necessary to verify the long-term effects of osteochondral transplantation.

Animals↗