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Biomedical subjects

O Yamaguchi

Publications and source records attributed to O Yamaguchi.

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

Functional evidence for involvement of bumetanide-sensitive Na+K+2CI- cotransport in the hepatoportal Na+ receptor of the Sprague-Dawley rat.

To investigate mechanisms involved in hepatoportal Na+ sensing, responses of hepatic afferent nerve activity (HANA) to intraportal hypertonic NaCl injection were measured before, and after, intraportal infusion of inhibitors of Na+ transport systems. HANA increased in response to the intraportal injection of 0.75 M NaCl in a dose-dependent manner. The HANA response was not affected by amiloride or 4-acetamido-4'-isothiocyanato-stilbene-2,2'-disulfonic acid (SITS), but was suppressed in a dose-dependent manner by intraportal infusion of ouabain, furosemide, or bumetanide. These results indicate that the hepatoportal Na+ receptor senses the Na+ concentration via the bumetanide-sensitive Na+K+2Cl- cotransporter.

4-Acetamido-4'-isothiocyanatostilbene-2,2'-disulfo↗
PubMed1999

Expression and possible functional role of the beta3-adrenoceptor in human and rat detrusor muscle.

PURPOSE: To investigate the presence of the beta3-adrenoceptor (beta3-AR) in human and rat detrusor muscle and the usefulness of beta3-AR agonists as drugs for the treatment of urinary frequency. MATERIALS AND METHODS: FK175, ethyl [(S)-8-[(R)-2-(3-chlorophenyl)-2-hydroxyethylamino]-6,7,8,9-tetrah ydro-5H-benzocyclohepton-2-yloxy]acetate monohydrochloride monohydrate, was used as a beta3-AR selective agonist. The expression of beta-AR subtypes (beta1-, beta2-, beta3-AR) mRNA was investigated in rat and human detrusor muscle by RT-PCR. Beta3-AR agonist induced cyclic AMP (cAMP) levels were measured in rat detrusor muscle strips. The relaxation response produced by a beta3-AR agonist was measured in a KCl induced tonic contraction model in rat detrusor muscle strips. The effect of a beta3-AR agonist on urinary bladder function was investigated by cystometry using a conscious rat model of urinary frequency. RESULTS: beta3-AR mRNA was substantially expressed in both rat and human detrusor muscles. The beta3-AR agonist, FK175 (10(-7) M), increased the cAMP level by 30% in rat detrusor muscle. In isolated rat detrusor muscle strips contracted with KCl, the beta3-AR agonist, FK175 (10(-8) to 10(-4) M), produced a concentration-dependent relaxation. Moreover, although the relaxation induced with FK175 was blocked by the non-selective beta-AR antagonist, bupranolol, it was unaffected by ether the beta1-AR selective antagonist, CGP 20712A, or the beta2-AR selective antagonist, ICI 118551, suggesting that FK175 induced the relaxation via the beta3-AR. Furthermore, in the rat model, the orally administered beta3-AR agonist, FK175 (10 mg./kg.) significantly increased bladder capacity with no change of micturition pressure or threshold pressure. CONCLUSIONS: These results suggest that beta3-AR agonists may be effective in the treatment of urinary frequency.

Adrenergic beta-Agonists↗
PubMed1998

Enhancement of mycinamicin production by dotriacolide in Micromonospora griseorubida.

Production of macrolide antibiotic mycinamicin was greatly increased by addition of sulfate ion into the culture medium of Micromonospora griseorubida. An O-sulfate ester compound, also produced by the strain, was shown to be dotriacolide. In an M. griseorubida dotriacolide non-producing strain, the production level of mycinamicin remained low, but increased to the level of dotriacolide producing strain by the addition of dotriacolide. Dotriacolide enhanced mycinamicin production in M. griseorubida by the formation of micelles with mycinamicin. As a result, dotriacolide played a critical role in mycinamicin production in M. griseorubida.

Anti-Bacterial Agents↗
PubMed1998

A new assay for classical swine fever virus based on cytopathogenicity in porcine kidney cell line FS-L3.

A new assay termed the dome disappearance method for classical swine fever virus (CSFV) using FS-L3 cells with serum-free culture medium was developed. The CSFV live vaccine GPE- strain grows well and shows a slight cytopathic effect (CPE) in FS-L3 cells. This CPE results in the disappearance of the unique fluid-filled multicellular domes on a single monolayer of FS-L3 cells. By using this phenomenon, dome disappearance, as a marker of infection, it was possible to determine the titers of CSFV and its neutralizing antibody. The virus titer determined by this method shows a good correlation with that determined by immunochemical and interference methods. Furthermore, the amount of neutralizing antibody measured by this method also correlated with that measured by the Exaltation of Newcastle Disease Virus (END) neutralizing method. The dome disappearance method developed in this experiment is a simple and safe procedure and has the great advantage that bovine serum, which may contain antibody against bovine viral diarrhea virus, is not necessary for the cultivation of FS-L3 cells.

Animals↗
PubMed1998

Effect of naloxone on the bladder activity of rabbits with acute spinal injury.

BACKGROUND: Naloxone enhances bladder activity in patients with chronic spinal cord injury. However, there are few reports on naloxone for bladder morbidity in acute spinal cord injury. METHODS: We performed a prospective, controlled study of the effects of naloxone on bladder function in rabbits with and without surgical transection of the spinal cord at the 10th thoracic vertebra. Acute and chronic stages of injury were defined according to bladder function. Naloxone was given intravenously at both stages, and intrathecally at the acute stage. Bladder activity was monitored by cystometry. Blood concentrations of methionine-enkephalin were measured by radioimmunoassay. RESULTS: Spinal cord injuries were acute 1 or 2 days after surgery, and chronic after 1 or 2 weeks. Bladder capacity significantly decreased after 0.01 mg of intravenous naloxone in uninjured control rabbits, and after 0.03 mg of intravenous naloxone in rabbits with chronic-phase injuries. During the acute-injury phase, 0.3 mg of intravenous naloxone, or 0.02 mg of intrathecal naloxone, was necessary to evoke the micturition reflex. No significant changes in blood enkephalin levels were seen before or after spinal cord injury. CONCLUSION: In rabbits with acute spinal cord injury, intrathecal naloxone evoked the micturition reflex at a much lower dose than did intravenous naloxone. Intrathecal naloxone promises to become a new therapy for the acute stage of spinal cord injury for active recovery of bladder function, and could replace current therapy.

Animals↗
PubMed1998

Role of the liver in long-term control of drinking behavior, Na+ balance, and arterial pressure in Dahl rats.

The role of postabsorptive mechanisms in long-term control of drinking behavior, Na+ balance, and arterial pressure was examined in Dahl salt-sensitive (DS) and salt-resistant (DR) rats. NaCl (0.15 M) was infused (0.5 ml/h) into either the inferior vena cava (IVC) or the portal vein (PV) for 7 days, and then 1.5 M NaCl was infused for 10 days. During 1.5 M infusion, the IVC group retained more Na+ than the PV group. Furthermore, in DS rats, mean arterial pressure was higher in the IVC group than in the PV group. Regardless of the strain and infusion route, 1.5 M infusion had no effect on volume of daily saline consumption. However, when the data for light and dark periods were analyzed separately, dark period saline consumption in the PV group was decreased by 1.5 M infusion but was not changed in the IVC group. These results indicate that, in Dahl rats, the postabsorptive mechanism plays a significant role in controlling long-term saline drinking behavior and Na+ balance and has a significant role in controlling arterial pressure in DS, but not DR, rats.

Animals↗
PubMed1998

[A case of polyorchidism with embryonal carcinoma].

Polyorchidism is a rare anomaly with approximately 70 cases reported in the literature. We reported a case of polyorchidism with embryonal carcinoma, the first case, in one of 4 testes. Polyorchidism with malignancy had been reported in 5 cases and bilateral polyorchidism in 3 cases. Authors have not been clarified whether the incidence of malignancy in polyorchidism is high or low. But we have to treat the patients with polyorchidism carefully, because polyorchidism is highly associated with cryptorchidism.

Adult↗
PubMed1998

[A case of neutropenic enterocolitis in high dose chemotherapy with peripheral blood stem cell transplantation for relapsed testicular tumor].

High dose chemotherapy with peripheral blood stem cell transplantation (PBSCT) is safe and useful for the treatment of refractory or relapsed testicular tumors, but is sometimes accompanied by serious complications. We report a case of relapsed testicular tumor complicated by neutropenic enterocolitis during high dose chemotherapy with PBSCT.

Adult↗
PubMed1997

Calcium independent contraction of bladder smooth muscle.

BACKGROUND: Recently, it has been suggested that in vascular smooth muscle a Ca(2+)-independent mechanism or Ca(2+)-sensitization of contractile elements may participate in smooth muscle contraction. In this study, we evaluate this mechanism in detrusor muscle. METHODS: Strips of smooth muscle from rabbit aorta, rabbit bladder and human bladder were evaluated by in vitro contraction studies. RESULTS: The results show that (1) in Ca(2+)-free solution containing ethyleneglycol bis (-aminothylether)-N,N,-tetraacetic acid (EGTA), carbachol and phorbol ester produced sustained contractions in detrusor muscle (Ca(2+)-free contraction); (2) depletion of Ca2+ stores by caffeine did not affect Ca(2+)-free contraction induced by carbachol; and (3) W-7 (calmodulin inhibitor) and ML-9 (myosin light chain kinase [MLCK] inhibitor) did not show inhibitory effects on Ca(2+)-free contraction, while H-7 (protein kinase C. [PKC] inhibitor) abolished this contraction. CONCLUSIONS: These results suggest that neither stored Ca2+ nor the Ca(2+)-calmodulin-MLCK system is involved in the carbachol-induced Ca(2+)-free contraction of detrusor muscle. This Ca(2+)-independent contraction seems to be mediated by the activation of PKC coupled with agonist stimulation of the muscarinic receptor.

Aged↗
PubMed1997

[Transurethral balloon laser thermotherapy for benign prostatic hyperplasia].

Between April 1994 and March 1995, transurethral balloon laser thermotherapy (TUBAL-T) using Prostalase was performed on 53 patients with benign prostatic hyperplasia. Clinical efficacy was evaluated at 3 months after TUBAL-T. The mean international prostate symptom score (I-PSS) decreased from 21.5 at baseline to 11.3 after 3 months (p < 0.0001). Irritative (the sum of items 1, 2, 4 and 7 of I-PSS) decreased by 55%, while obstructive symptoms (the sum of items 3, 5 and 6 of I-PSS) by 45%. However, other objective parameters such as maximum flow rate, voided volume, percent postvoid residual volume and prostate volume showed no significant change (7.8 to 7.2 ml/s, 130 to 147 ml, 33 to 28% and 39.7 to 41.0 ml, respectively). In conclusion, significant improvement after TUBAL-T was observed for subjective symptoms, especially irritative symptoms, but not for objective parameters.

Aged↗
PubMed1997

[Neoadjuvant intra-arterial chemotherapy based on chemosensitivity tests for locally invasive bladder cancer].

We investigated the clinical usefulness of individualization of chemotherapeutic regimen in neoadjuvant intra-arterial chemotherapy for locally invasive bladder cancer. Anticancer drugs were selected according to the results of an in vitro chemosensitivity test (collagen matrix assay or succinic dehydrogenase inhibition test). Nine patients with locally invasive bladder cancer received 1 to 4 courses of neoadjuvant intra-arterial chemotherapy, followed by radical cystectomy. Histopathological responses in the cystectomized specimens were grade 3 in 3 cases, grade 2 in 2, grade 1b in 2 and no response in 2. Pathologically, a complete response and downstaging were observed in 3 and 4 cases, respectively. Seven of the 9 patients were alive no evidence of disease with a mean follow-up period of 38.9 months, whereas 2 patients died of metastasis within 2 years. Six of the 7 patients who showed a complete response or down staging have been free of recurrence. These findings suggest that our chemotherapeutic strategy may improve the prognosis for locally invasive bladder cancer.

Aged↗
PubMed1996

Estimate criteria for diagnosis and severity in benign prostatic hyperplasia.

BACKGROUND: Standard severity criteria for benign prostatic hyperplasia (BPH) are needed to facilitate clinical and epidemiologic investigations in the common terminology. PATIENTS AND METHODS: A total of 692 BPH patients from 8 institutions were judged by specialized physicians for their overall disease severity and severity in 4 domains: symptom, function, anatomy, and quality of life (QOL). The items measuring severity in these 4 domains were the International Prostate Symptom Score (I-PSS) questionnaire, uroflowmetry, transrectal ultrasonography (TRUS), and questionnaires on bother and I-PSS QOL index, respectively. By Spearman's rank correlation and multiple regression analysis using physicians' judgement as the criterion variable (gold standard) the items and their cut-off levels were selected so that high predictivity, practicality and clinical significance were maintained, while the number of items in use was minimized. RESULTS: The item(s) and their ranges of values for each severity grade were summarized as follows; the evaluation domain (the selected item(s): range of mild, moderate, severe): symptom (I-PSS: 0-7, 8-19, 20-35), function (maximum flow rate and residual urine volume: > or = 15 mL/s and < 50 mL, > or = 5 mL/s and < 100 mL, < 5 mL/s or > or = 100 mL), anatomy (prostate volume on TRUS: < 20 mL, < 50 mL, > or = 50 mL), QOL (QOL index: 0 and 1, 2 to 4, 5 and 6). The overall severity was efficiently predicted when defined according to the combinations of severity grades of the 4 domains. These criteria predicted physicians' judgement with accuracy of about 80% for overall severity and severity of individual domains. CONCLUSION: The proposed criteria are valid, practical, and would be useful for the common scale of the BPH severity in clinical and epidemiologic studies.

Humans↗
PubMed1996

Estimate criteria for efficacy of treatment in benign prostatic hyperplasia.

BACKGROUND: Various treatment modalities for benign prostatic hyperplasia (BPH) have emerged and are now in use or await evaluation of clinical usefulness. It is difficult, however, to compare their efficacies on a single scale, because standardized criteria for therapeutic efficacy of BPH treatments have not been established. PATIENTS AND METHODS: A total of 692 BPH patients from 8 institutions in Japan received various treatments, and were judged by specialized physicians for overall efficacy, and for efficacy in 4 domains: symptom, function, anatomy, and quality of life (QOL). Efficacy of treatment was graded as excellent, good, fair or poor, and assessed using items based on conventional clinical measurements. These items included 1) the difference (post-pretreatment value), 2) relative ratio (post/pre) and, 3) the individual values of pre- or posttreatment measurements. The cut off levels for each grade were heuristically selected by Spearman's rank correlation and multiple regression analysis so that the results accurately predicted physicians' judgement, while the feasibility was maintained. RESULTS: The results for each efficacy grade (range of excellent, range of good, range of fair, range of poor) were summarized as follows: Symptom: (post/pre treatment ratio of I-PSS) < or = 0.25, < or = 0.5, < or = 0.75, > 0.75. Function: (post-pre of Qmax) > or = 10 mL/s, > or = 5 mL/s, > or = 0.25 mL/s, < 0.25 mL/s. Anatomy: (post/pre ratio of prostate volume) < or = 0.5, < or = 0.75, < or = 0.9, > 0.9. QOL: (pre-post of QOL index) > or = 4, 3, 2 and 1, < or = 0. The overall efficacy grade was defined as the median of efficacy grades of 3 domains: symptom, function and QOL. The agreement rates between the criteria and physicians' judgement on the dichotomous efficacy (either excellent plus good, or fair plus poor) were approximately 80% in individual domains and overall estimate, and consistent among various treatments. CONCLUSION: The proposed criteria are fairly accurate, simple, and practical, and thus may be useful as a standard method for assessing the clinical efficacy of BPH treatments.

Evaluation Studies as Topic↗
PubMed1996

Clinical applicability of a new tactile sensor for evaluating rigidity of the penis: a comparative study with Rigiscan.

BACKGROUND: A new tactile sensor was developed for detecting hardness of living tissue by Omata et al. in 1992. This paper reports applicability of the sensor for evaluation of penile rigidity. METHODS: Nine patients from a group of 12 patients with penile erectile dysfunction were selected as subjects of this study. All patients agreed to artificial erection and monitoring of penile rigidity by a new tactile sensor and the Rigiscan system. The 9 patients selected all developed more than 1 cm circumferential expansion of the penis after an injection of smooth muscle relaxant into the corpus cavernosum. The sensor equipment consisted of a piezoelectric element that vibrated, and a pickup that detected vibration frequency. When the end of the sensor was pressed against a surface of the penis, the resonance frequency of the sensor changed and indicated rigidity of the organ. Rigidity of the penile shaft was simultaneously monitored with the sensor and the Rigiscan system before and after an injection of 40 mg papaverine or 20 micrograms prostaglandin E1. The sensor's measurements of rigidity were compared with those of Rigiscan. RESULTS: Reproducibility of rigidity measured with the tactile sensor was satisfactory. Statistical analysis was made on 85 simultaneous pairs of rigidity values from the tactile sensor and Rigiscan. The analysis indicated significant correlation between the values. CONCLUSION: The tactile sensor as well as Rigiscan will be of use for evaluating rigidity of the penis.

Adult↗
PubMed1996

[Histological effects of short term endocrine therapy on prostatic cancer].

BACKGROUND: The objective of this study is to investigate the pathological changes which occurred in prostatic cancer shortly after the commencement of endocrine therapy. METHODS: Fourty-three patients underwent radical prostatectomy immediately after the short term endocrine therapy (treatment period was within one month) and the histological pictures of operative specimens were compared to those obtained from the pretreatment biopsy specimens. RESULTS: Degenerative changes of cancer cells, such as nuclear and cytoplasmic vacuole, collapse of the cytoplasm and the appearance of naked hyperchromatic nucleus were noticed after the short term endocrine therapy. Especially in the cases which were histologically evaluated to be poorly differentiated in the biopsy specimens, not only degenerative changes but also destruction of cancer nests caused by cell death were observed. The histological effects affected by short term endocrine treatment had no relation to the prognosis, but in the cases of stage D2, the pathological grade judged by post-therapeutic specimens were found to be useful for the prediction of prognosis. CONCLUSION: Endocrine therapy induces remarkable pathological changes in prostatic cancer within a very short time after beginning treatment.

Aged↗
PubMed1996

Combination therapy of Pseudomonas aeruginosa pyelonephritis in neutropenic mice with human antilipopolysaccharide monoclonal antibody and cefsulodin.

PURPOSE: These studies were designed to determine the combined inhibitory effect of a human monoclonal antibody (MAb) and cefsulodin on Pseudomonas aeruginosa renal infection in a neutropenic condition. MATERIALS AND METHODS: Protection against the infection of mice was estimated by survival rate and bacterial numbers in the kidney and blood. Opsonophagocytic assay by human polymorphonuclear neutrophils (PMNs) and fluorescence activated cell sorter (FACS) analysis were also examined. RESULTS: Treatment of infected mice with MAb combined with a suboptimal dose of cefsulodin prevented the mice from developing pyelonephritis and bacteremia and resulted in a significantly higher survival rate than treatment with either MAb or cefsulodin alone (p < 0.01). When bacteria were preexposed to cefsulodin, a significant enhancement in opsonophagocytic killing with MAb was observed. Fluorescence activated cell sorter analysis suggested that the bacteria incubated with 1/4 minimal inhibitory concentration (MIC) of cefsulodin showed greater binding of MAb to bacteria than the control. CONCLUSION: The combination therapy with human antilipopolysaccharide MAb and cefsulodin is useful for P. aeruginosa pyelonephritis in neutropenic hosts.

Animals↗
PubMed1996

Evaluation of mRNAs encoding muscarinic receptor subtypes in human detrusor muscle.

PURPOSE: The present study evaluated the muscarinic receptor subtypes corresponding to m1 to m5 genes in human detrusor muscle. MATERIALS AND METHODS: The mRNAs encoding m2 and m3 subtypes were assessed by reverse transcription (RT)-polymerase chain reaction (PCR). The amounts of cDNA synthesized from m2 and m3 mRNAs were measured by using subcloned plasmid DNAs. The distribution of m2 and m3 mRNAs in detrusor was estimated by comparing the amount of m2 cDNA with that of m3 cDNA. RESULTS: The m2 mRNA:m3 mRNA ratio was 1.06:1.00 in human detrusor. In the cryostat sections of human detrusor, the presence of both m2 and m3 mRNAs was confirmed by in situ hybridization. However, the RT-PCR products derived from m1, m4 and m5 subtype mRNAs were not detected. CONCLUSION: These results suggest that human detrusor muscle coexpresses muscarinic m2 and m3 receptors and that the populations of the 2 subtypes are not significantly different.

Base Sequence↗