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Biomedical subjects

N Suzuki

Publications and source records attributed to N Suzuki.

At least 487 records · Page 27Linked to original sources
PubMed1998

Transurethral ureterolithotomy in 100 lower ureteral stones.

A total of 100 patients with lower ureter stones received transurethral ureterolithotripsy (TUL) using a pulsed dye laser and/or a pneumatic lithotriptor. Extracorporeal shock wave lithotripsy treatment was added in 15 patients because fragments larger than 4 mm had been pushed back to the renal pelvis. The median stone size was 8 mm (range 3-22 mm). Operative time ranged between 3 and 157 min with a median of 30 min. Stone size correlated well with impaction, when impaction was defined as the inability of a guidewire to pass over the stone. Complete removal was defined as total clearance at 1 month without retreatment. The overall stone-free rate was 93%. Among the 7 not-stone-free cases, 5 cases were considered to have been treated successfully because asymptomatic residual fragments were smaller than 4 mm, 1 case required retreatment to become stone free, and 1 case with a silent residual fragment of 8 mm had been followed up for 3 months. The success rate was 98% when successful treatment was defined as total clearance or the presence of asymptomatic residual fragments of 4 mm or less without retreatment. Impaction was not a significant determining factor of stone-free rate (95.7 and 86.7%, respectively, p > 0.05) and in situ stone-free rate (TUL alone; 85.7 and 76.7%, respectively, p > 0.05). Two minor ureteral perforations were encountered. No patient required percutaneous nephrostomy or open surgery, or showed any late complications. TUL is a safe and successful method in managing lower ureteral stones.

Adolescent↗
PubMed1998

Mesangial expression of a nonmuscle myosin heavy chain, SMemb, is associated with glomerular sclerosis and renal prognosis in IgA nephropathy.

To characterize the phenotypic alteration in mesangial cells in human glomerulonephritis, we investigated the expression of nonmuscle-type myosin heavy chain, SMemb, and alpha-smooth muscle actin (alpha-SM actin) in IgA nephropathy. The expression of SMemb and alpha-SM actin was examined by immunohistochemistry in biopsy specimens from 45 patients with IgA nephropathy. We examined a total of 489 glomeruli representing all patients enrolled, and found that mesangial expression of SMemb and alpha-SM actin was associated with mesangial proliferation. Only mesangial expression of SMemb showed a significant relationship with mesangial matrix accumulation. Semiquantitative evaluation using composite expression scores showed that the expression of SMemb was elevated in the patients with poor renal prognosis. The expression of alpha-SM actin showed no significant relationship with renal prognosis. These results suggest that mesangial expression of SMemb is an important factor in the progression of IgA nephropathy, and that SMemb and alpha-SM actin are associated with the activation of mesangial cells by different mechanisms.

Adolescent↗
PubMed1998

Efficacy of oral magnesium administration on decreased exercise tolerance in a state of chronic sleep deprivation.

We have previously reported that chronic sleep deprivation causes a deficiency of intracellular magnesium (Mg) and decreased exercise tolerance. The aim of this study was to clarify whether oral administration of Mg could be effective in restoring the exercise tolerance that is decreased by chronic sleep deprivation. A bicycle ergometer cardiopulmonary exercise test was performed by 16 healthy volunteers (mean age 21.9 years). They were divided into 2 groups: 8 received doses of 100 mg of Mg orally per day for 1 month (Mg group) and the remaining 8 received no Mg and served as the control group. The study conditions were designed as follows: (1) the usual state (good sleep); and (2) the sleep-deprived state (sleeping time up to 60% less than the usual state for 1 month). The ratio of intracellular Mg content of the sleep-deprived state to the usual sleep state was significantly higher in the Mg group (p<0.05) than the untreated control group. There was no difference between the sleep-deprived state and the usual state with regard to anaerobic threshold and peak oxygen uptake in the Mg group, whereas both of these decreased in the sleep-deprived state in the control group. These results indicate that decreased exercise tolerance observed in the sleep-deprived state could be improved by oral Mg administration.

Administration, Oral↗
PubMed1998

Effects of transforming growth factor alpha and hepatocyte growth factor on acid-induced damage in rat gastric epithelial cells.

We examined the effects of transforming growth factor alpha (TGF-alpha) and hepatocyte growth factor (HGF) on acid-induced damage in a rat gastric epithelial cell line. Pretreatment of cells for 30 min with TGF-alpha, but not HGF, significantly prevented the acid-induced cell damage in a concentration-dependent manner. Genistein significantly reduced the protective effect of TGF-alpha. DNA synthesis in RGM1 cells was increased when the cells were incubated with TGF-alpha and HGF for 24 hr. We conclude that the protective effect of TGF-alpha against acid-induced damage seems to be caused by the activation of Na+/H+ exchangers and not by enhanced DNA synthesis.

Animals↗
PubMed1998

Spontaneous larval Gnathostoma nipponicum infection in frogs.

From June 1993 to September 1997, a survey was carried out for the prevalence of larval Gnathostoma nipponicum infection in several kinds of frogs, toads, and their tadpoles collected from an endemic area of this nematode in Aomori Prefecture. Two frog species, one of 436 (0.2%) Rana nigromaculata and 51 of 147 (34.7%) R. catesbeiana were infected, and a total of 446 advanced third-stage larvae (AdL3) of G. nipponicum were recovered. These results confirmed that two frog species which can serve as the second intermediate and/or paratenic hosts in the life cycle of G. nipponicum exist in nature. This report is the first record of spontaneous infection of frogs with AdL3 of G. nipponicum.

Animals↗
PubMed1998

Growth inhibitory effect of bovine lactoferrin to Toxoplasma gondii tachyzoites in murine macrophages: tyrosine phosphorylation in murine macrophages induced by bovine lactoferrin.

Previous studies have shown that lactoferrin induces growth inhibitory effects in mouse macrophages against intracellular Toxoplasma gondii, and these effects were not mediated by the oxygen-dependent and inorganic nitrogen-dependent pathway. To clarify the mechanism of anti-Toxoplasma gondii activity induced by lactoferrin, we examined whether lactoferrin promoted the phosphorylation of tyrosine residues in macrophage proteins. In immunoblotting assays using anti-[phosphorylated tyrosine] monoclonal antibody, phosphorylation of tyrosine residues was detected in protein(s) of approximately 30 kDa in macrophages incubated with lactoferrin. Inhibition of the lactoferrin-induced tyrosine-phosphorylation by genistein led to loss of the lactoferrin-induced growth inhibitory effect against the parasites. These findings suggest that lactoferrin induces tyrosine-phosphorylation in macrophages, and the tyrosine-phosphorylation seems to be associated with the induction of the growth inhibitory activity exerted against intracellular Toxoplasma gondii.

Animals↗
PubMed1998

MRI of cervical intervertebral discs in asymptomatic subjects.

We studied degenerative changes in the cervical intervertebral discs of 497 asymptomatic subjects by MRI and evaluated disc degeneration by loss of signal intensity, posterior and anterior disc protrusion, narrowing of the disc space and foraminal stenosis. In each subject, five disc levels from C2-C3 to C6-C7 were evaluated. The frequency of all degenerative findings increased linearly with age. Disc degeneration was the most common observation, being present in 17% of discs of men and 12% of those of women in their twenties, and 86% and 89% of discs of both men and women over 60 years of age. We found significant differences in frequency between genders for posterior disc protrusion and foraminal stenosis. The former, with demonstrable compression of the spinal cord, was observed in 7.6% of subjects, mostly over 50 years of age. Our results should be taken into account when interpreting the MRI findings in patients with symptomatic disorders of the cervical spine.

Adolescent↗
PubMed1998

Growth hormone inhibits its own secretion by acting on the hypothalamus through its receptors on neuropeptide Y neurons in the arcuate nucleus and somatostatin neurons in the periventricular nucleus.

GH secretion is regulated by hypothalamic somatostatin and GH-releasing factor. It has been postulated that GH feeds back on the hypothalamus and regulates its own secretion. We focused our attention on the action of GH in the hypothalamus in relation to GH secretion. Adult male rats were used throughout the studies, and the observation was made in conscious rats. Systemic administration of human GH induced c-fos gene expression, a marker of neuronal activity, in the hypothalamic arcuate nucleus (ARC) and the periventricular nucleus (PeV) in hypophysectomized male rats. The major cells in which c-fos gene expression was induced were neuropeptide Y (NPY) neurons in the ARC and somatostatin neurons in the PeV. GH receptor mRNA was demonstrated to be present in these neurons by in situ hybridization. The injection of a small dose of rat GH into the ARC or PeV inhibited GH secretion, whereas microinjection of IGF-I into these nuclei did not. Intracerebroventricular injection of NPY suppressed GH secretion, and this effect was abolished by anterolateral deafferentation of the medial basal hypothalamus (MBH), a procedure which disrupts the somatostatinergic input to the MBH. Taken together, these findings suggest that GH acts on NPY neurons in the ARC and somatostatin neurons in the PeV through GH receptor, and the activation of these neurons augments somatostatin release and inhibits GH secretion.

Animals↗
PubMed1998

Establishment of a new human megakaryoblastic cell line, CMY, with chromosome 17p abnormalities.

A new megakaryoblastic cell line CMY was established from a Down's syndrome patient suffering from acute megakaryoblastic leukemia. The karyotypes of CMY showed deletion of chromosome 17 or the translocation of 17p, whereas the blasts of the patient did not reveal these abnormalities of chromosome 17 by conventional karyotype analysis. Blasts of the patient failed to respond to chemotherapy and complete remission could not be attained. The abnormalities of 17p became progressively predominant in the patient. These results suggest that the blasts of a minor clone which had the abnormalities of chromosome 17p might have existed in the patient from the beginning and CMY was established from the minor clone. Investigation of p53 gene by PCR-SSCP analysis revealed that blasts of the patient showed normal patterns, while CMY showed an abnormally migrating band in exon 5 alone. This result suggests that another novel oncogenic factor(s) besides p53 might be present on chromosome 17p and other tumor suppresser genes need to be studied.

Cell Differentiation↗
PubMed1998

Mutagenicity of microcystin-LR in human RSa cells.

Microcystin-LR (MCLR) is a potent cyclic heptapeptidic hepatotoxin produced by bloom-forming cyanobacteria. The mutagenicity induced by this compound in cultured human RSa cells was found by determination of ouabain-resistant (OuaR) mutation, with the highest frequency at the concentration of 15 microgram/ml. Moreover, base substitution mutations at K-ras codon 12 in genomic DNA, assessed by polymerase chain reaction (PCR) and differential dot-blot hybridization using digoxigenin-labeled probes, were detected in RSa cells 6 days after exposure to MCLR (7.5-15 microgram/ml).

Cells, Cultured↗
PubMed1998

Activation of MAP kinases by 5-fluorouracil in a 5-fluorouracil-resistant variant human cell line derived from a KT breast cancer cell line.

To investigate the mechanism of the acquired resistance of human cells to an anticancer drug, 5-fluorouracil (5-FU), a drug-resistant clone, KTFU-4, was isolated from a human KT breast carcinoma cell line, treated with ethylmethanesulfonate and then with 5-FU. The viability of the KT cells, analyzed using an MTT assay, was suppressed by 5-FU in a dose-dependent manner, while that of the KTFU-4 cells was enhanced by it at concentrations between 0.1 and 1.0 microgram/ml. Treatment of KTFU-4 cells with 5-FU resulted in increased amounts of activated phosphorylated ERK1/2 and p38 MAP kinases, but not in the parent KT cells. It is thus possible that 5-FU stimulated the proliferation of KTFU-4 cells by activating a signal transduction pathway leading to cell growth.

Antimetabolites, Antineoplastic↗
PubMed1998

Relationship between vascular endothelial growth factor and angiogenesis in spontaneous and indomethacin-delayed healing of acetic acid-induced gastric ulcers in rats.

Angiogenesis is an important event for gastric ulcer healing. Vascular endothelial growth factor (VEGF) is known to be a potent stimulator of angiogenesis. This study consequently examined VEGF production, VEGF mRNA expression and angiogenesis during the spontaneous and indomethacin-delayed healing of acetic acid-induced ulcers in rats. The production of VEGF, taking place in the normal mucosa, was significantly elevated by ulceration. The mRNA expression of three isoforms of VEGF (VEGF188, VEGF164 and VEGF120) was also detected. Following the increase in VEGF production, angiogenesis was significantly promoted in the ulcer base. VEGF-immunoreactivity was observed in granulocytes, fibroblasts and regenerated epithelial cells. Indomethacin markedly inhibited prostaglandin E2 synthesis in the ulcer base, resulting in the prevention of ulcer healing. Angiogenesis was also significantly inhibited by indomethacin, but neither VEGF production nor VEGF mRNA expression was reduced. Such results suggest that VEGF might play a role in angiogenesis in the spontaneous healing of gastric ulcers in rats. However, the inhibition of angiogenesis in indomethacin-delayed ulcer healing is not explainable on VEGF expression.

Acetic Acid↗
PubMed1998

3D and 4D atlas system of living human body structure.

A reference system for accessing anatomical information from a complete 3D structure of the whole body "living human", including 4D cardiac dynamics, was reconstructed with 3D and 4D data sets obtained from normal volunteers. With this system, we were able to produce a human atlas in which sectional images can be accessed from any part of the human body interactively by real-time image generation.

Anatomy, Cross-Sectional↗
PubMed1998

Simulator for virtual surgery using deformable organ models and force feedback system.

This paper describes a real-time surgery planning system using virtual reality techniques. This system allows us to simulate incision of skin and organs which respond as elastic objects with surgical tools in virtual space. Inner structures such as blood vessels and lesions can be seen and manipulated in the simulation. In addition to these functions we attempted to add a feedback function that responds to the operator's hands. We developed a force feedback device to manipulate the elastic organ model based on pressure from the operator's fingers.

Abdomen↗
PubMed1998

Metabolism of dacarbazine by rat liver microsomes contribution of CYP1A enzymes to dacarbazine N-demethylation.

The N-demethylation of dacarbazine in liver microsomes was significantly increased by treatment of rats with beta-naphthoflavone, dexamethasone, or phenobarbital. However, the extent of increase in the N-demethylation observed in beta-naphthoflavone-treated rats was much greater than that observed in dexamethasone-treated rats. A good correlation between N-demethylation of dacarbazine and O-deethylation of phenacetin was observed when a low concentration of phenacetin was used. Furthermore, the activity of dacarbazine N-demethylase in rat liver microsomes was highly correlated with the amounts of CYP protein immunochemically determined with anti-rat CYP1A2 antibodies. In addition, antibodies to rat CYP1A2, and furafylline and alpha-naphthoflavone, which are known inhibitors of CYP1A enzymes, exhibited inhibitory effects on dacarbazine N-demethylation. These results indicated that CYP1A enzymes may be responsible for N-demethylation of dacarbazine in rat liver microsomes.

Animals↗
PubMed1998

[Familial pulmonary arteriovenous malformation diagnostic of the Osler-Weber-Rendu disease].

A 53-year-old woman was admitted to the hospital for investigation of an abnormal shadow in the middle lobe of the right lung on a chest X-ray film. The filling of most of the shadowed area with contrast media on a chest CT scan suggested a vascular lesion. Further investigation by intravenous digital subtraction angiography and color doppler sonography led to the diagnosis of pulmonary arteriovenous malformation. An abdominal CT scan suggested the presence of an arteriovenous malformation in the liver, and a bronchoscopic study revealed telangiectatic lesions on the laryngeal mucosa. The patient's father had died at the age of 61, due to intracranial bleeding, which suggested he might have had an arteriovenous malformation in the brain. The patient's daughter has a pulmonary arteriovenous malformation. This family of vascular malformation indicates that the patient had Osler-Weber-Rendu disease. Osler-Weber-Rendu disease is an autosomal-dominant inherited disorder that may give rise to arteriovenous malformations, mainly in the lungs and the brain. We found that color doppler sonography can be useful for the diagnosis of pleural-based pulmonary arteriovenous malformation.

Adult↗
PubMed1998

[Tuberculosis of the central nervous system experienced at the International Medical Center of Japan].

In spite of recent advances in diagnosis and chemotherapy of tuberculosis, prognosis of tuberculosis of the central nervous system (CNS) is still poor. We evaluated clinical characteristics of 14 patients with the CNS tuberculosis (10 male and 4 female, 21 to 71 years of age) who were hospitalized at IMCJ from 1988 to 1997. Twelve patients had tuberculous meningitis (2 of them had also intracranial tuberculoma), 1 had intracranial tuberculoma and 1 had spinal cord tuberculosis. For the acid-fast bacilli, the smears of cerebrospinal fluids (CSF) were all negative but the cultures for M. tuberculosis were positive in 5. Using PCR method, M. tuberculosis was identified from CSF specimens in 2 out of 9 culture negative patients, thus suggesting the usefulness of the PCR for the rapid diagnosis of CNS tuberculosis. The adenosine deaminase (ADA) levels in CSF may provide another diagnostic clue because they were elevated in 8 out of 10 cases. It is to be noted that there were three patients who developed clinical manifestations of CNS tuberculosis after the initiation of chemotherapy for pulmonary tuberculosis. In the last five cases, four-drug regimen which included PZA, was used with a good result. The success could be related to the addition of PZA which penetrates blood-brain barrier just as good as INH. Two patients died and one remains unconscious with severe neurological sequelae. The present study indicates that positive CSF culture, hydrocephalus and consciousness disturbance are important factors in determining poor prognosis of the CNS tuberculosis.

Adult↗