Biomedical subjects

T Yamaguchi

Publications and source records attributed to T Yamaguchi.

At least 433 records · Page 24Linked to original sources

PubMed1999

Long-term ursodeoxycholic acid therapy is associated with reduced risk of biliary pain and acute cholecystitis in patients with gallbladder stones: a cohort analysis.

Whether ursodeoxycholic acid (UDCA) therapy alters the long-term clinical course of gallstones (GS) without stone dissolution remains unknown. We aimed to clarify the relationship between long-term UDCA therapy and risks of biliary pain or acute cholecystitis in GS patients. We also aimed to identify factors affecting the natural course, and to explore a simple patient selection criteria for UDCA therapy. A cohort of 527 uncomplicated GS patients with or without UDCA (600 mg/d) followed for up to 18 years was analyzed. Patients who had frequent attacks or were complicated with cholecystitis were converted to cholecystectomy. History and UDCA therapy were identified on Cox analysis as 2 factors affecting the long-term clinical course. In patients without therapy, history was the only predictor of biliary pain among various patient or stone characteristics; biliary pain was rare in asymptomatic patients, while frequent in symptomatic patients (P <.001). UDCA therapy was associated with reduced risk for biliary pain in both symptomatic (62% vs. 92% in untreated patients at 10 years; P <.001; relative risk, 0.19; 95% CI, 0.10-0.34) and asymptomatic patients (6% vs. 12% in untreated patients at 10 years; P =.037; relative risk, 0.19; 95% CI, 0.04-0.91). Risk for the conversion was also reduced in UDCA-treated symptomatic patients (26% vs. 88% in untreated patients at 10 years, P <.001; relative risk, 0.08; 95% CI, 0.03-0.22). These effects were independent of stone dissolution. Three factors were identified on Cox analysis as affecting GS dissolution: radiolucency, small size (<10 mm) of stones, and visualized gallbladder (GB) on cholecystogram. A selection criteria based on these appears to exhibit high sensitivity (74%) and specificity (95%) for dissolution. UDCA therapy might be considered in symptomatic patients fulfilling these criteria, and also in patients who have significant surgical risk, because the longterm therapy is clearly associated with reduced risk of biliary pain and acute cholecystitis.

Acute Disease↗

PubMed1999

Carbon monoxide-mediated alterations in paracellular permeability and vesicular transport in acetaminophen-treated perfused rat liver.

This study aimed to examine whether acetaminophen (AAP), an anti-inflammatory agent producing hepatocellular damages with its overdose, evokes hepatocellular dysfunction through mechanisms involving carbon monoxide (CO) generated by heme oxygenase (HO). In perfused rat livers, CO and bilirubin were determined in venous perfusate and bile samples as indices of heme degradation. Biliary excretion of transportally injected horseradish peroxidase was also determined to assess paracellular junctional permeability and vesicular transport across hepatocytes. AAP at 20 mmol/L induced a transient choleresis, followed by a reduction of bile output. Under these circumstances, the release of CO and bilirubin IXalpha, terminal products of the HO-mediated heme degradation, became 2. 5-fold greater than the control. The rate of CO production appeared stoichiometric to the degradation rate of microsomal cytochrome P-450. Mechanisms for the AAP-induced cholestasis involved an increase in the junctional permeability that coincided with a reduction of vesicular transport across hepatocytes. Clotrimazole, a cytochrome P-450 inhibitor, or zinc protoporphyrin IX, an HO inhibitor, but not copper protoporphyrin IX, which did not inhibit HO, attenuated these AAP-induced changes. Furthermore, administration of CO at concentrations comparable with those induced by AAP elicited a marked elevation of the paracellular junctional permeability concurrent with a reduction of transcellular vesicular transport, mimicking effects of the AAP administration. Thus, CO serves as a putative regulator of hepatocellular function that is overproduced through acute heme degradation during xenobiotic transformation.

Acetaminophen↗

PubMed1999

Growth potential of loose bodies: an immunohistochemical examination of primary and secondary synovial osteochondromatosis.

Histologic and immunohistochemical studies of growth potential were performed on 53 surgically removed loose bodies representing 10 cases of primary synovial osteochondromatosis, 37 bodies representing 12 cases of secondary synovial osteochondromatosis, and five bodies representing five cases of osteochondral fracture. Loose bodies in primary synovial osteochondromatosis were nodular, showing plump chondrocytes and irregular calcification, and all contained proliferative cell nuclear antigen-positive chondrocytes (labeling index: 42.5%; range: 36.0-52.0%). Other markers stained less frequently. Loose bodies in secondary synovial osteochondromatosis showed uniform chondrocytes and annular calcification surrounding core tissue. Eighteen of 37 loose bodies showed proliferative cell nuclear antigen-positive chondrocytes, mostly peripherally. Chondrocyte labeling indices were less than 5% for proliferative cell nuclear antigen and other markers, although some connective tissue cells in the outer layer were stained. Loose bodies from osteochondral fractures were composed of articular cartilage, subchondral bone, and connective tissue; cartilage was negative for markers, whereas connective tissue contained positive cells. One specimen showed cartilaginous metaplasia of connective tissue. These results suggest that loose bodies have the potential for slow growth by proliferation of chondrocytes in primary synovial osteochondromatosis and by metaplasia following proliferation of surrounding connective tissue in secondary synovial osteochondromatosis.

Adolescent↗

PubMed1999

Shortened elastase infusion time in the elastase-induced rat aneurysm model.

OBJECTIVE: This study was performed to determine whether it would be possible to shorten the elastase infusion time in the elastase-induced rat aneurysm model. METHODS: The abdominal aortas of 76 male Sprague-Dawley rats were dissected and infused for 10, 20, 30, 60, or 120 min with a solution containing 14 U of elastase or for 30 min with saline solution (control). After infusion, the rats were evaluated every day for calculation of the mortality rate. On day 7, the surviving rats underwent laparotomy. The diameter of the aorta was measured, and the aortic tissue was excised for histologic examination. RESULTS: There were no deaths among the rats infused for 10, 20, or 30 min. The mortality rate was 64% in the 60-min and 90% in 120-min groups. There were no significant differences in the diameters of the 30-min saline-infused aortas and the 10- or 20-min elastase-infused aortas. The diameter of the 30-min elastase-infused aortas (6.2 +/- 2.1 mm) was significantly larger (P < 0.01) than the diameters of the 10- and 20-min elastase-infused aortas. There were no significant differences between the 30-min and the 60- and 120-min elastase-infused aortas. Microscopically, there was total or subtotal loss of elastic tissue and marked inflammatory cell infiltration of the aortic wall in the 30-, 60-, and 120-min elastase-infused aortas. CONCLUSIONS: It is possible to shorten the elastase infusion time from 120 to 30 min in the elastase-induced rat aneurysm model. This shortening of infusion time reduces the experimental time and mortality rate.

Animals↗

PubMed1999

Pharmacological properties of a novel gastrointestinal prokinetic benzamide selective for human 5-HT4 receptor versus human 5-HT3 receptor.

Binding properties of gastrointestinal prokinetic benzamides for both cloned human 5-hydroxytryptamine (5-HT)3 receptors and cloned human 5-HT4 receptors were examined and pharmacological properties of YM-53389{(+)-(S)-2-chloro-5-methoxy-4-[5-(2-piperidylmethyl)-1,2, 4-oxadiazol-3-yl]aniline monohydrochloride} were characterised in animals. Cisapride, renzapride and zacopride inhibited specific binding of [3H]ramosetron to cloned human 5-HT3 receptors, with Ki values of 684, 7.64 and 0.38 n m, respectively. YM-53389, however, slightly replaced that (Ki>10,000 n m). YM-53389, cisapride, renzapride and zacopride replaced specific binding of [3H]GR 113808 to cloned human 5-HT4 receptors, with Ki values of 54.6, 41.5, 115 and 373 n m, respectively. The potency for inhibitory effect of YM-53389 on 5-HT3 receptor-mediated contraction in the guinea-pig isolated colon was very low with pIC50 of 4.7. YM-53389 exerted 5-HT4 receptor-mediated relaxation in the carbachol-precontracted rat isolated oesophagus with pEC50 of 6.3. In mice, YM-53389 at 10 and 30 mg kg-1, s.c. significantly shortened whole gut transit time, in contrast to cisapride, renzapride and zacopride which were reported to delay that. YM-53389 had no significant effect on upper gastrointestinal propulsion at doses up to 30 mg kg-1, s.c. Based on these results, YM-53389 may surpass existing benzamides in facilitating lower intestinal propulsion and benefit patients with gastrointestinal disorders associated with impair of intestinal propulsion, such as constipation, based on the selective interaction with human 5-HT4 receptors vs human 5-HT3 receptors.

Animals↗

PubMed1999

Iodine-131 human-mouse chimeric Fab monoclonal antibody A7 guided surgery for colorectal cancer patients: a pilot study.

This study was conducted to determine the clinical usefulness of radioimmunoguided surgery (RIGS) using human-mouse chimeric Fab monoclonal antibody A7 (ch-Fab-A7) for colorectal cancer patients. Ten colorectal cancer patients were given iodine-131-labeled ch-Fab-A7 intravenously (i.v.) 2 to 7 days prior to RIGS. The RIGS was carried out using a portable gamma detecting probe (GDP). Tumor localization was identified by GDP intraoperatively in 4 of the ten patients, while liver metastasis and lymph node metastasis were identified in 2 patients and 1 patient, respectively. The GDP revealed tumor/surrounding tissue radio(gamma)count ratios of 1.5 or greater in 8 of the ten resected tumors. Although RIGS using ch-Fab-A7 is a promising tool for intraoperatively identifying the tumor localization of colorectal cancer, 125I, rather than 131I, should be used as a tracer for RIGS to enhance the accuracy of ch-Fab-A7.

Adenocarcinoma↗

PubMed1999

Effectiveness of an inferior vena caval filter as a preventive measure against pulmonary thromboembolism after abdominal surgery.

In three patients with a previous history of pulmonary thromboembolism, inferior vena caval filters were inserted before elective laparotomies to prevent a recurrent pulmonary thromboembolism. Two patients had colon cancer and underwent colectomies, while the other had myoma uteri, which might have been the cause of deep vein thrombosis, and thus a hysterectomy was performed. In spite of their poor risks, their postoperative courses were fairly good owing to perioperative management including anticoagulant therapy, and no recurrence has been observed since the operation in every case. A pulmonary thromboembolism is a fatal complication which follows deep vein thromboses. In patients with such a previous history, the risk is much higher after a laparotomy because of long-term bed rest, hypercoagulability, and so on. The mortality rate after a recurrence of pulmonary thromboembolism is reported to reach 30% without adequate therapy, whereas it is reduced to 8% with anticoagulant therapy, and to 0.8% with additional inferior vena caval filter placement. Considering the feasibility of insertion and the low incidence of complications, preoperative inferior vena caval filter placement is thus recommended for patients having a previous history of either pulmonary thromboembolism or deep vein thrombosis.

Aged↗

PubMed1999

The effects of a new ultra-short-acting beta-adrenergic blocker, ONO-1101, on cardiac function during and after cardiopulmonary bypass.

The administration of an ultra-short-acting beta-adrenergic antagonist, esmolol, has been introduced as a novel method for beating-heart surgery. In the present study, a new ultra-short-acting beta-blocker, ONO-1101, was administered during cardiopulmonary bypass (CPB) to investigate its effects on cardiac function and hemodynamics. Nine adult mongrel dogs underwent 60 min of CPB during which they were given either ONO-1101 (ONO group; n = 4) or saline (control group; n = 5). In the ONO group, the hearts became flaccid enough for surgery to be performed without cardiac standstill within 10 min after the commencement of ONO-1101 with significant decreases in the heart rate, the preload recruitable stroke work (PRSW), and the slope of the end-systolic left ventricular pressure-volume relationship (Emax). The mean arterial pressure and systemic vascular resistance also decreased, but were maintained above 50 mmHg during CPB without catecholamine. These indices increased to the control group level 20 min after the discontinuation of ONO-1101. The serum concentration of ONO-1101 decreased from the maximum level of 121 +/- 15 microg/ml soon after infusion to 11 +/- 5 microg/ml within 30 min after discontinuation. These data suggest that ONO-1101 may be useful to enable beating-heart surgery to be performed without aortic cross-clamp as an ultra-short-acting beta-adrenergic blocker.

Adrenergic beta-Antagonists↗

PubMed1999

Guideline of surgical management based on diffusion of descending necrotizing mediastinitis.

BACKGROUND: Descending necrotizing mediastinitis resulting from oropharyngeal abscess, is a serious, life-threatening infection. Exisiting strategies for surgical management, such as transcervical mediastinal drainage or aggressive thoracotomic drainage, remain controversial. METHODS: Four patients, (three males and one female) were treated for descending necrotizing mediastinitis resulting from oropharyngeal infection. Two had peritonsillar abscesses, while the others experienced dental abscess and submaxillaritis. Descending necrotizing mediastinitis received its classification according to the degree of diffusion of infection diagnosed by computed tomography. Mediastinitis in two cases, (Localized descending necrotizing mediastinitis-Type I), was localized to the upper mediastinal space above the carina. In the others, infection extended to the lower anterior mediastinum (Diffuse descending necrotizing mediastinitis-Type IIA), and to both anterior and posterior lower mediastinum (Diffuse descending necrotizing mediastinitis-Type IIB). The spread of infection to the pleural cavity occurred in three cases. RESULTS: The surgical outcome concerning each of the patients was successful. Radical cervicotomy (unilateral in three patients, bilateral in the other) in conjunction with mechanical ventilation with continuous postoperative positive airway pressure, was performed in all cases. Tracheostomy was established in three patients and pharyngostomy in two. The two descending necrotizing mediastinitis-Type I cases were successfully managed with transcervical mediastinal drainage. The descending necrotizing mediastinitis-Type IIA case received treatment through transcervicotomy and anterior mediastinal drainage through a subxiphoidal incision. The patient with descending necrotizing mediastinitis-Type IIB required posterior mediastinal drainage through a right standard thoracotomy followed by left minimal thoracotomy. CONCLUSIONS: The mediastinal infection, the extent of which has been accurately determined by computed tomograms, necessitates radical cervicotomy followed by pleuromediastinal drainage. Situations where infection has spread to posterior medisatinum, particularly when it reaches in the level of the carina (descending necrotizing mediastinitis-type I), may not always require aggressive mediastinal drainage. In comparison, diffuse descending necrotizing mediastinitis-Type IIB demands complete mediastinal drainage with debridement via thoracotomy. Subxiphoidal mediastinal drainage without sternotomy may provide adequate drainage in diffuse descending necrotizing mediastinitis-Type IIA.

Abscess↗

PubMed1999

Serum levels of Clara cell 10-kDa protein are decreased in patients with asthma.

Clara cell 10-kDa protein (CC10), the predominant product from nonciliated cells in the epithelial lining of bronchioles (Clara cells), has been shown to have immunomodulatory and antiinflammatory activity and may play a role in controlling airway inflammation. This study was designed to measure serum CC10 concentrations in healthy and asthmatic nonsmokers. Serum CC10 concentrations in asthmatic nonsmokers were significantly lower than in healthy nonsmokers. Asthmatic patients with a long duration of the disease (>/=10 years) had significantly lower serum CC10 levels than those with a short duration of the disease (<10 years). There was no significant difference in serum CC10 levels in asthmatic patients between the time of the asthmatic attack and the stable condition. Serum CC10 levels may reflect decreased production of CC10 caused by remodeling of the small airways in asthma.

Asthma↗

PubMed1999

Cherubism: clinicopathologic features.

A case of cherubism in 6-year-old boy is reported. He presented with bilateral symmetrical enlargement of the jaw in addition to medially dislocated premature teeth, narrow V-shaped palatal vault, and mild upward turning of the eyes. Radiographs showed multiloculated osteolysis in both the mandible and maxilla. Histology revealed a non-neoplastic fibrous lesion, rich in multinucleated giant cells, consistent with giant-cell reparative granuloma. Since the original description of cherubism, various histologic interpretations have been proposed, particularly that of fibrous dysplasia. However, it should be emphasized that cherubism is a disease histologically indistinguishable from giant-cell reparative granuloma.

Cherubism↗

PubMed1999

Primary hepatic carcinoid tumor.

A primary hepatic carcinoid tumor arising in a 49-year-old woman is reported. The patient was admitted with multiple hepatic tumors and treated by a left lobectomy and cholecystectomy. Cut sections of the specimen revealed a solid and necrotic mass, measuring 10 x 12 x 13 cm, with multiple small satellite nodules. Histologically, the tumor cells had small oval-shaped nuclei and presented with a trabecular arrangement and rosette-like formation. Both Grimelius and Fontana-Mason stainings were positive. The tumor cells were positive for chromogranin A and negative for other antigens. Ultrastructural studies of the tumor cells revealed duct-like formation with microvilli and a cluster of dense small immature neurosecretory granules in the cytoplasm. These findings were consistent with those of carcinoid tumors. Postoperatively, the patient was treated with repeated transcatheter arterial chemoembolization for any remnant tumors. However, she died of the disease 5 years after the initial surgery. The autopsy findings suggested the primary site to be the liver.

Antineoplastic Agents↗

PubMed1999

Late pleuropulmonary aspergillosis after the treatment of pneumothorax: report of three cases.

A bullectomy for spontaneous pneumothorax is often combined with pleurodesis to prevent recurrence. A recurrent or progressive residual bullous lung beneath adhesive pleura neovascularized from the chest wall may be affected by aspergillosis. Of the 12 patients with pulmonary aspergillosis secondary to bullous lung disease treated surgically at our hospital since 1974, 3 underwent a bullectomy with pleurodesis for spontaneous pneumothorax. The presenting symptoms in all cases were hemosputum. Aspergillus lesions affected the patients in the right upper lobe, the left apical segment, and both apical segments at 16, 9, and 13 years, respectively, after a bullectomy. Angiograms demonstrated hypervascularization in the intercostal and internal thoracic arteries, as well as in the bronchial branches. Catheter embolization for airway bleeding was not effective in 1 patient. Four operations, including an emergency procedure for massive intrapulmonary bleeding, were performed. These included a right upper lobectomy followed by a left upper segmentectomy at second-look operation in 1 patient who required bilateral chest wall resections. All patients survived the operations. Intraoperative bleeding ranged between 700 and 3 500 ml (1 543 ml on average), and bleeding foci were mainly from the chest wall, with hypervascularization stemming from the ipsilateral chest wall. Postoperative complications included pleural space hemorrhaging and a bronchopleural fistula, both of which required additional chest wall resections. Patients with bullous lung disease late after a bullectomy with pleurodesis may thus be associated with complex pleuropulmonary aspergillosis, which requires surgical therapy concomitant with a chest wall resection.

Adult↗

PubMed1999

Rapid mass screening method and counseling for the 1555A-->G mitochondrial mutation.

The 1555A-->G point mutation is associated with a susceptibility to aminoglycoside antibiotics, and is of particular interest, as it may cause hearing loss even without aminoglycoside exposure. There may be a considerably large high-risk population in Japan, and to avoid possible side effects in this group, a rapid mass screening system and careful counseling are recommended. We are currently using the mutant allele specific amplification (MASA) method to detect the 1555A-->G mitochondrial mutation and we distribute a warning card to subjects found to bear this mutation.

Aminoglycosides↗

PubMed1999

Intracoronary surface changes after Palmaz-Schatz stent implantation: serial observations with coronary angioscopy.

BACKGROUND: The objective of this study was to evaluate the appearance of the intraluminal surface after Palmaz-Schatz stent implantation by using coronary angioscopy. METHODS AND RESULTS: Coronary angioscopy was performed immediately after stenting and at 1, 3, and 6 months later in 43 patients with 45 lesions. The presence or absence of red thrombus and/or dissection and the extent of neointimal coverage of the stent struts were analyzed. Immediately after stenting, red thrombus and dissection were observed in 9 (41%) and 12 (56%) of 22 lesions, respectively, and these rates decreased with time. Complete coverage of the stent struts by smooth white neointima was observed in 55% of 11 lesions at 1 month and in 80% of 21 lesions at 3 months. However, incomplete neointimal coverage was seen in 3 lesions at both 3 and 6 months. CONCLUSIONS: In human coronary arteries, neointimal coverage of an implanted Palmaz-Schatz stent may take as long as 6 months or more.

Angina Pectoris↗

PubMed1999

Leu518Pro mutation of the beta ig-h3 gene causes lattice corneal dystrophy type I.

PURPOSE: To describe a Japanese family with lattice corneal dystrophy type I, which segregates with a novel mutation, Leu518Pro of the beta ig-h3 gene. METHODS: DNA was extracted from leukocytes in four members (three affected and one unaffected) of a Japanese family with lattice corneal dystrophy type I. Exon 12 of the beta ig-h3 gene was amplified and analyzed with a molecular biologic method. Clinical data were also collected. RESULTS: Three generations of this family have been positively diagnosed with lattice corneal dystrophy, indicating autosomal dominant inheritance. We found a heterozygous point mutation that segregates with the disease phenotype. It was a single base-pair transition (CTG to CCG, Leu to Pro). CONCLUSION: Although it is extremely rare compared with the Arg124Cys mutation of the beta ig-h3 gene, Leu518Pro mutation of the beta ig-h3 also causes lattice corneal dystrophy type I.

Adolescent↗

PubMed1999

Semiquantitative evaluation of alpha1A-adrenoceptor subtype mRNA in human hypertrophied and non-hypertrophied prostates: regional comparison.

The main purpose of this study was to compare semiquantitatively the amount of alpha1a-adrenoceptor subtype mRNA in urethral, central and peripheral areas in benign hypertrophied prostates and non-hypertrophied prostate by the competitive reverse transcriptase polymerase chain reaction (RT-PCR) method. Prostates from twenty cases of men with benign prostatic hypertrophy (BPH) and 5 cases of bladder tumor without BPH were obtained for this study. The mRNA was extracted from the urethral, central and peripheral areas of each prostate, and quantitative RT-PCR was performed using the ratio of PCR product of alpha1a-adrenoceptor mRNA/beta2-microglobulin mRNA. The ratio for the central area of the hypertrophied prostate was significantly greater than that for the same area of the non-hypertrophied prostate (p < 0.05). In contrast, the urethral area showed no significant difference between the two prostate conditions. The central area of the hypertrophied prostate showed the tendency to have an increased alpha1a-adrenoceptor mRNA level compared with the urethral area, though no statistical difference was recognized because of the high standard error. Regional differences in the alpha1a-adrenoceptor mRNA in the non-hypertrophied prostate were rarely observed. The present finding demonstrates that the increased alpha1a-adrenoceptor mRNA content found in the hypertrophied prostate (1) was due to that in the central area.

Aged↗

PubMed1999

Postnatal ontogeny of GTP binding protein in the human frontal cortex.

The postnatal development of G protein in membrane preparations from frontal cortex regions in postmortem brains of various ages was investigated by immunoblotting with polyclonal antibodies against several specific G protein subtypes (the short and long form of Galphas(:Gs), Galphai1.2(:Gi), Galphao(:Go) and Galphaq/11(:Gq)) and tubulinbeta, and functional photoaffinity GTP binding. The amounts of Go showed steep increases at about 2 years, and there were similar tendency about Gs, Gi1.2 and Gq/11. Moreover, tubulinbeta was constant with development. The guanine nucleotide binding of Gs, Gi and Go also transiently increased at about the age of 2 years but the ratio of Gs to Gi.o was unchanged. Our results might have relevance for developmental neuroplasticity in signal transduction.

Adolescent↗