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Biomedical subjects

K Miyake

Publications and source records attributed to K Miyake.

At least 181 records · Page 10Linked to original sources
PubMed1996

Effect of magnesium on the function of the rabbit corpus cavernosum.

Contraction and relaxation of the smooth muscle, including the corpus cavernosum, are mediated by changes in the intracellular concentration of calcium. Since magnesium modulates the movement of calcium, it can modify the function of the erectile tissue. We designed this study to investigate the effects of magnesium in doses ranging from 5 to 30 mM on the function of the rabbit corpus cavernosum in vitro. The resting tension of tissue strips was significantly reduced by exposure to a solution high in magnesium (5-30 mM). The contractile response to field stimulation under resting conditions, and the contraction to phenylephrine, were significantly decreased by magnesium (5-30 mM). There were no differences in the contractile strength of the corpus cavernosum to KCl. Although the relaxation induced by field stimulation under preincubation with 200 microM phenylephrine was abolished in the presence of 30 mM magnesium, there were no differences at a concentration of 5 mM or of 10 mM magnesium. The relaxation induced by sodium nitroprusside under precontraction with 200 microM phenylephrine was further increased by magnesium dose dependently. A high concentration of magnesium (30 mM) enhanced both bethanechol-induced and ATP-induced relaxations under precontraction with phenylephrine. Our study demonstrated that magnesium reduced the receptor-mediated contraction of the rabbit corpus cavernosum and enhanced the relaxation of this tissue induced by sodium nitroprusside, bethanechol, and ATP.

Animals↗
PubMed1996

Blocking adhesion of cancer cells to endothelial cell types by S. agalactiae type-specific polysaccharides.

By using immortalized and normal endothelial cells, we were able to detect inhibitory effects of type specific polysaccharides from Streptococcus agalactiae on adhesion of cancer cells to endothelial cells, which is an essential step of cancer metastatis. The inhibition was probably due to specific structures of the bacterial polysaccharides, since the structures of the saccharides are very similar to those of cancer specific sialyl Lewis carbohydrates (sialyl Le(a) and Le(x)) which bind to ELAM-1 of endothelial cells. This result indicated that the bacterial polysaccharides from S. agalactiae could be very useful and hopeful as cancer metastasis inhibitors.

Antineoplastic Agents↗
PubMed1996

Dislocation of the lens nucleus into the vitreous cavity after standard hydrodissection.

PURPOSE: Having encountered dislocation of the lens nucleus into the vitreous cavity immediately after continuous tear capsulorhexis and hydrodissection of the nucleus, we examined common features of eyes with this complication. METHODS: We reviewed consecutive cases of cataract extraction. RESULTS: The complication occurred in four of 10,126 eyes. All four eyes were in elderly patients and except for the patient whose contralateral eye had pseudoexfoliation syndrome, all eyes had an increased axial length. CONCLUSION: In elderly patients with eyes that have a long axial length or pseudoexfoliation, we recommend performing hydrodissection with extreme care and only when necessary.

Aged↗
PubMed1996

Correlation between intraocular lens hydrophilicity and anterior capsule opacification and aqueous flare.

PURPOSE: To study the correlation between a basic parameter of intraocular lens biocompatibility, hydrophilicity, and two clinical parameters, postoperative inflammation and anterior capsule opacification. SETTING: Miyake Eye Hospital, Nagoya, Japan. METHODS: Three combinations of IOLs that were identical in shape but had distinct contact angles of water were used in this prospective double-masked study: (1) experimental comparison of collagen type IV and poly(methyl methacrylate) (PMMA) IOLs in rabbit eyes; (2) clinical comparison of heparin-surface-modified and PMMA IOLs; (3) clinical comparison of three foldable IOLs, silicone, acrylic, and memory. One of the two IOLs being compared in each situation was randomly assigned to both eyes of each animal or patient. At 1 and 3 months postoperatively, the degree of anterior capsule opacification and the amount of flare in the anterior chamber were determined. RESULTS: In all three comparative situations, greater postoperative inflammation and more rapid anterior capsule opacification was seen in the eyes with hydrophobic IOLs. CONCLUSION: There was a correlation between the hydrophilicity of an IOL and the severity of postoperative inflammation and the speed of anterior capsule opacification.

Acrylic Resins↗
PubMed1996

Jak3 expression in glomerular epithelia of IgA nephropathy (IgA-N) patients.

Jak3 is a member of the Janus kinase family which plays an important role in cytokine signal transduction. Jak3 associates the gamma(c) chain of receptors for IL-2, IL-4, IL-7, IL-9 and IL-15, and is essential for the signal transduction of these cytokines. We have isolated Jak3 kinase from renal mesangial cells and demonstrated the constitutive expression of Jak3 in glomeruli in vivo. To investigate the physiological and pathological role of Jak3 in glomeruli, we prepared anti-Jak3 antibody and analysed the localization of Jak3 in glomeruli of renal biopsy samples from various nephritis patients and normal subjects. Among 61 nephritis patients and four normal subjects investigated in the present study, Jak3 was selectively localized to glomerular epithelia of IgA-N patients (14/34 cases) and focal glomerulosclerosis patients (1/5 cases), but not detected in minimal changes (n = 6), membranous glomerulonephropathy (n = 7), crescentic glomerulonephritis (n = 4), lupus nephritis patients (n = 5), and normal subjects (n = 4). The intense immunoreactivity for Jak3 is significantly associated with the decrease in creatinine clearance (81.5 +/- 10.4 ml/min versus 104.3 +/- 29.6 ml/min; P < 0.05, Student's t-test) and the increase in level of serum creatinine (1.13 +/- 0.33 mg/dl versus 0.75 +/- 0.23 mg/dl; P < 0.01, Student's t-test) in IgA-N patients. Furthermore, gamma(c) chain was concomitantly expressed with Jak3 in glomerular epithelia in vivo and in vitro, suggesting that signal transduction via gamma(c)-Jak3 cascade may be involved in the pathogenesis of glomerular injury of IgA-N. Taken together with the recent findings that IL-4-secreting T lymphocytes in affected glomeruli injure glomerular epithelium, the responsiveness of glomerular epithelium for IL-4 may be pathologically enhanced in IgA-N.

Animals↗
PubMed1996

Serum prostate-specific antigen values for the prediction of clinical stage and prognosis in patients with prostate cancer: an analysis of 749 cases.

BACKGROUND: The clinical significance of pretreatment serum prostate-specific antigen (PSA) values was studied to determine the ability to predict clinical stage and prognosis using a relatively large number of patients with prostate cancer. METHODS: Serum PSA values at diagnosis were analyzed from 749 patients with newly-diagnosed prostate cancer and registered in the Tokai Urological Cancer Registry. Correlations between the PSA value, the clinical stage and prognosis of the patients were evaluated. RESULTS: Serum PSA values at each stage of diagnosis showed positivity (> or = 3.6 ng/mL) in 23% (stage A1) to 91.2% (stage D2) of patients, and it was possible to obtain statistical differences between the stages, even between A1 and A2. Based on a cumulative study of PSA distribution, stages greater than A2 could be diagnosed using a cut-off of 7.2 ng/mL, with a 99.2% positive predictive value (PPV), and a 16.2% negative predictive value (NPV). At a PSA level of 10.8 ng/mL, stages greater than B2 could be predicted with a PPV of 95.3% but an NPV of 40.3%. Pretreatment PSA values were a significant prognostic indicator in stage D2 patients using 100 to 150 ng/mL as the cut-off values. These differences were primarily found in the poorly differentiated group, which showed a statistical difference using cut-off PSA values from 75 to 150 ng/mL. CONCLUSIONS: Serum PSA levels from a large number of patients can be used to predict the stage and prognosis of prostate cancer patients.

Aged↗
PubMed1996

Successful pregnancy after intracytoplasmic injection of a single testicular spermatozoon into a human oocyte: a case report.

Testicular sperm was retrieved from a man with an epididymal obstruction, and an intracytoplasmic sperm injection was made into his wife's oocytes. In 4 mature oocytes treated, 2 fertilized eggs were obtained, and a clinical pregnancy was established with embryo transfers. Our experience demonstrated the possibility of fertilization and conception with testicular sperm.

Adult↗
PubMed1996

Effects of delayed treatment with nafronyl oxalate on microsphere embolism-induced changes in monoamine levels of rat brain regions.

1. The present study was undertaken to examine the effects of delayed treatment with nafronyl oxalate (nafronyl), a cerebral vasodilator, on monoamine neurotransmitters of brain regions in the microsphere-embolized rat. 2. Microsphere embolism was induced by injecting 900 microspheres with a diameter of 48 microns into the right internal carotid artery of rats. Microsphere-embolized rats were treated with nafronyl, 15 mg kg-1, i.p., twice daily from the first to the 5th day. Levels of monoamines and their metabolites in the cerebral cortex, striatum, and hippocampus were measured on days 3 and 5 after the operation by a high-performance liquid chromatograph with electrochemical detection. In vivo tyrosine or tryptophan hydroxylation was estimated by measurement of the accumulation of 3, 4-dihydroxyphenylalanine or 5-hydroxy-1-tryptophan after administration of 3-hydroxybenzylhydrazine dihydrochloride, an inhibitor of aromatic L-amino acid decarboxylase. 3. Microsphere embolism induced decreases in dopamine, noradrenaline and 5-hydroxytryptamine in three brain regions of the right hemisphere on days 3 and 5. In the left hemisphere, the monoamines were reduced, but to a lesser degree than in the right hemisphere. On days 3 and 5, the decrease in the monoamines of the right hemisphere was attenuated by nafronyl treatment except for noradrenaline on day 3. The decrease in the monoamines levels in the left hemisphere was almost completely prevented by nafronyl treatment. 4. On day 3 after microsphere embolism, in vivo tyrosine and tryptophan hydroxylation was lower than the pre-embolic value in all three brain regions. Treatment of the embolized rats with nafronyl significantly attenuated the decrease in in vivo tyrosine and tryptophan hydroxylation in the ipsilateral hemisphere, but not hippocampal tryptophan hydroxylation. 5. The results suggested that treatment with nafronyl improves or attenuates changes in monoamine neurotransmitter metabolism of the brain regions impaired by microsphere embolism. The mechanisms underlying this effect may be attributed to preservation of the ability to synthesize monoamines when the brain is ischaemic or oligaemic.

3,4-Dihydroxyphenylacetic Acid↗
PubMed1996

Infectivities of human and other primate lentiviruses are activated by desialylation of the virion surface.

The envelope protein, gp120, of human immunodeficiency virus type 1 (HIV-1) is heavily glycosylated and sialylated. The heavy sialylation greatly affects the physical properties of the protein, as it resolves into a wide acidic pH range despite the basic pI value predicted for its polypeptide backbone (B. S. Stein and E. G. Engleman, J. Biol. Chem. 265:2640-2649, 1990). However, the functional significance of the heavy sialylation remains elusive. Here, we show that desialylation of HIV-1 with neuraminidase greatly augments the initial virus-cell interaction, leading to remarkably enhanced viral replication and cytopathogenicity. This enhancement appeared to be a direct result of the removal of negatively charged sialic acids but not of the exposure of galactose residues or complement activation. Complementing these results, studies with inhibitors of mannosidase I and mannosidase II showed that the processing of HIV-1 oligosaccharides into the complex type to acquire the terminal sialic acid residues impeded the full replication capacity of the virus and that its prevention also enhanced virus replication and cytopathogenicity. Enhancement of infection by desialylation was found widely, with HIV-1 laboratory strains of different cell tropisms and primary isolates as well as HIV-2 and simian immunodeficiency virus. Thus, the sialylation catalyzed by host cell pathways appeared to reduce the infectivity of human and nonhuman primate lentiviruses. Our results further suggested that desialylation would help increase the titers of HIV-based vectors.

1-Deoxynojirimycin↗
PubMed1996

Abnormal expression of the human CD44 gene in early colorectal malignancy with special reference to variant exon 9 (9v).

AIMS: To examine the expression of CD44 variant exon 9 in early colorectal malignancies. METHODS: Formalin fixed, paraffin wax embedded tissue sections from 30 cases of tubular adenoma and 35 cases of adenoma with focal carcinoma of the colon were examined immunohistochemically using a monoclonal antibody (MAb 11.24) directed against CD44-9v. RESULTS: In the normal colorectal mucosa immunoreactivity was confined to the basal part of the crypts and was expressed in less than 10% of crypt cells. CD44-9v was expressed in the superficial part of tubular adenoma with mild atypia in 67% of the cases and in 19% of the tumour cells. The immunoreactivity was observed along the basement membrane in mild atypia, as in the non-neoplastic crypts. In the course of progression to severe atypia the spatial polarity of immunoreactivity was lost, and the extent of CD44-9v expression increased in intensity and in the percentage of positive cases and positive cells. In the carcinomatous lesions of adenoma with focal carcinoma, 94% of the cases and 44% of the tumour cells were positive for CD44-9v protein. CONCLUSION: CD44-9v may be overexpressed at the early stage of colorectal tumorigenesis and this increase continues throughout the course of the disease.

Adenoma↗
PubMed1996

Urinary 28-kD calbindin-D as a new marker for damage to distal renal tubules caused by cisplatin-based chemotherapy.

Calbindin-D, a vitamin D-dependent calcium-binding protein of 28 kD, is found predominantly in the distal tubules of the kidney and central nervous system tissues in humans. To evaluate damage to the renal tubules caused by cisplatin-based chemotherapy, levels of urinary and serum calbindin-D were determined in patients treated with cisplatin- or carboplatin-based chemotherapies using a highly sensitive enzyme immunoassay system developed in our laboratory. Levels of urinary 28-kD calbindin-D were also determined in patients with benign and malignant urological diseases. The mean urinary calbindin-D level was 2.44 + or - 0.31 (mean + or - SE) ng/mg creatinine in 40 healthy subjects. Urinary calbindin-D levels were elevated (>10 ng/mg creatinine) in 2 of 33 patients (6%) with benign and 1 of 50 (2%) with malignant urological diseases. Urinary calbindin-D levels were significantly increased after cisplatin-based chemotherapy in 14 patients, with peaks (71.8 + or - 13.5 ng/mg creatinine) being found 8 days after administration of cisplatin, and then a gradual return to the baseline. On the other hand, 7 patients receiving carboplatin-based chemotherapy demonstrated no significant elevation (highest level 7.7 + or - 2.5 ng/mg creatinine). In 7 patients treated with cisplatin-based chemotherapy the serum calbindin-D level was also raised after treatment, with a good correlation to urinary values. These findings suggest that urinary and serum calbindin-D may be kidney-derived and that 28-kDa calbindin-D is a useful marker for damage to the distal renal tubules associated with cisplatin-based chemotherapy.

Acetylglucosaminidase↗
PubMed1996

Radiation-induced urothelial carcinoma.

Four cases of urothelial carcinoma following pelvic irradiation for carcinomas of the cervix uteri (n = 3) and the ovary (n = 1) are reported. The urothelial carcinomas developed 26.8 (mean) years after radiotherapy and invaded the bladder in 3 patients and the ureter in 1. Despite radical surgery, the patients died of metastatic cancer.

Adult↗
PubMed1996

A case of intraperitoneal testicular cancer with ascites.

We report an initial case of intraperitoneal testicular cancer with ascites. Although the cytology of aspirated ascites revealed no tumor cells, the beta-HCG and AFP values were high. Preoperative cisplatin-based combination chemotherapy was used without any pathological diagnosis. Following 2 cycles of chemotherapy, the beta-HCG and AFP values normalized. Furthermore, no ascites was observed on CT scan. Although an accurate histological diagnosis was not established before treatment, it was thought that the ascites originated from the disseminated testicular cancer cells in the peritoneum.

Adult↗
PubMed1996

Chronic bacterial prostatitis treated with intraprostatic injection of antibiotics.

Direct transrectal infiltration of the prostate with antibiotics was performed in 25 selected patients with refractory chronic prostatitis, and sequential samples of urine and prostatic secretion were studied at 3-monthly intervals thereafter. The criterion for cure of chronic bacterial prostatitis was persistently sterile cultures of urine and prostatic secretion for at least 12 months after completion of treatment. Complete cure was obtained in 14 patients (56%) after one or two infiltrations. In seven other patients clinical and bacteriologic remission was obtained after several injections but the follow-up period was too short to judge the efficacy of the intraprostatic antibiotic administration. The remaining four patients (16%) had sterile specimen cultures 3 months after one injection, but were lost to further follow-up. The results suggest that local antibiotic treatment of chronic bacterial prostatitis is useful, although careful randomized studies with long follow-up are required to evaluate the merits of the method.

Adult↗
PubMed1996

[Diagnostic values and limitations of conventional urodynamic studies (uroflowmetry.residual urine measurement.cystometry) in benign prostatic hypertrophy].

PURPOSE AND METHODS: Diagnostic values and limitation of conventional urodynamic study (UDS) were assessed in 380 patients with benign prostatic hypertrophy (BPH), in terms of uroflowmetry, measurement of postvoid residual urine and cystometry. RESULTS: Maximum and average flow rate on uroflowmetry improved with increasing voided volume. Neither maximum nor average flow rate correlated with size of the prostate, subjective symptom (International Prostate Symptom Score) and bothersomeness for prostatism. Pre-TUR maximum flow rate did not predict outcomes on postoperative flow rate and surgical treatment failures. Uroflowmetry did not differentiate between obstruction and weakness of detrusor contraction. The intraindividual variation of postvoid residual urine was great and the volume of residual urine correlated poorly with subjective symptom, size of the prostate, maximum and average flow rate. On filling cystometry, although uninhibited detrusor contraction was much more frequently observed in patients with urge incontinence as compared with continent patients, there was no significant difference in other parameters between the two groups. Every parameter on cystometry did not correlate with nocturnal frequency. Postoperative persistence of urge incontinence did not correlate with the bladder volume at the first desire to void or at the maximum desire to void, an amplitude of uninhibited detrusor contractions, or bladder compliance. In some cases, evaluation of the intravesical pressure on voiding phase and uroflowmetry was diagnostic of apparent obstruction. CONCLUSIONS: In diagnosis of BPH, conventional UDS has limitation for certain and some caution showed be taken in interpretation of the data. However, since conventional UDS provides important and objective information on obstruction and detrusor function, which are independent of subjective symptom and prostate size, these should be necessary in diagnosis, determination of treatment options and evaluation of treatment outcomes in BPH.

Humans↗
PubMed1996

Effects of luteinizing hormone-releasing hormone (LH-RH) analogue on the function of the isolated rabbit corpus cavernosum.

An adverse effect of the administration of luteinizing hormone-releasing hormone (LH-RH) analogue is impotence. The effects of LH-RH analogue injection on the function of the rabbit corpus cavernosum were investigated. Eighteen male rabbits were divided into three groups, i.e., LH-RH analogue injection, castration, and sham-operated control groups. After measurement of serum testosterone, the LH-RH analogue (1.5 mg/kg leuprolide acetate) was injected once in the LH-RH group, castration in the castrated group, and sham surgery in the control group. Four weeks later, the rabbits were maintained in the same circumstance and serum testosterone was measured once a week. Four weeks after preparation, all rabbits were used for in vitro experiments. At one week the serum testosterone level of the LH-RH and castrated groups decreased significantly from that in the sham-operated control group, which was sustained for the next 3 weeks. Although contractile strength of the corporal tissue taken from the castrated group was weakened in response to phenylephrine and KCl, corporal contractile strength of the LH-RH group was not. Under precontraction with 200 microM phenylephrine relaxation of the corpus cavernosum in response to field stimulation and sodium nitroprusside significantly decreased in both the LH-RH and castrated groups. However, there were no differences in the maximal relaxations induced by ATP and bethanechol between the three groups. In conclusion, the LH-RH analogue impaired the relaxation of the corpus cavernosum induced by field stimulation and sodium nitroprusside as much as castration did. Although the corporal contraction to phenylephrine and KCl was decreased by castration, it was not altered by the LH-RH analogue.

Animals↗
PubMed1996

Effect of varicocelectomy on sperm parameters and pregnancy rate in patients with subclinical varicocele: a randomized prospective controlled study.

PURPOSE: We assessed whether subclinical varicocele ligation improves fertility and/or semen parameters. MATERIALS AND METHODS: A total of 85 patients with a subclinical varicocele diagnosed by scrotal thermography presented with infertility. Patients were randomly assigned to groups 1 (high ligation of the internal spermatic vein) and 2 (followed without any treatment). At least 3 semen samples were obtained at study entry and 1 year later in both groups. RESULTS: The pregnancy rate in group 1 was 6.7% compared to 10% in group 2, and the difference was not statistically significant. Group 1 had significantly higher levels of sperm density and total motile sperm count at 1 year. There were no significant differences between groups 1 and 2 regarding change in seminal volume, sperm motility and abnormal sperm morphology. CONCLUSIONS: Subclinical varicocelectomy has some effect on spermatogenesis but no beneficial effect on pregnancy rate.

Adult↗