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Biomedical subjects

K Ueno

Publications and source records attributed to K Ueno.

At least 73 records · Page 4Linked to original sources
PubMed2000

Identification of quantitative trait loci for serum cholesterol levels in stroke-prone spontaneously hypertensive rats.

The stroke-prone spontaneously hypertensive rat (SHRSP) has been reported to show significantly lower levels of serum total cholesterol than the normotensive control strain Wistar-Kyoto rat (WKY). Because selective inbreeding was conducted for stroke proneness, this concomitantly inherited characteristic of SHRSP may play some pathophysiological role in stroke. We evaluated the genetic determinants of the cholesterol trait by estimating heritability and subsequently by undertaking a genome-wide screen with 161 genetic markers in F(2) progeny involving SHRSP and WKY (104 male and 106 female rats). Three quantitative trait loci (QTLs) were detected on rat chromosomes 5, 7, and 15. Markers from the linked region on chromosome 15 indicated significant evidence of linkage with a maximal log of the odds (LOD) score of 7.7, whereas those on chromosomes 5 and 7 cosegregated with the trait in a sex-specific manner (the QTL close to genetic marker D5 Mit5 reached an LOD score of 7.3 in males, and that close to D7 Mit10 reached an LOD score of 3.2 in females). The male-specific QTL on chromosome 5 appeared to overlap with previously reported QTLs for stroke-associated phenotypes, but an identical gene (or genes) appeared unlikely to control these and the cholesterol traits simultaneously. In the present study, serum cholesterol levels were shown to be highly genetically determined in SHRSP (the heritability estimates are 76% in males and 83% in females), and 3 QTLs with substantial effects were identified. Further work, however, is required to clarify whether the cholesterol trait is related to the etiology of stroke or has been retained by chance through the inbreeding process in SHRSP.

Alleles↗
PubMed2000

Evaluation of radiological examination for sensorineural hearing loss.

The accuracy of radiological examinations has improved and their diagnostic ability has markedly increased. However, the cost of such examinations has also recently become an issue. In this study, the clinical significance of radiological examinations for sensorineural hearing loss (SNHL) was evaluated and the value of their utilization was reconsidered. A total of 1,276 ears of 724 patients who demonstrated unilateral or bilateral SNHL was studied retrospectively. Findings of radiological examinations such as plain X-ray (X-p), computed tomography (CT) and magnetic resonance imaging (MRI) of the brain or the temporal bone were investigated. Temporal bone X-p was usually performed to rule out acoustic tumors (AT). CT was further performed in 119 patients (16.4%) and MRI in 84 patients (11.6%) in total. The reasons or symptoms for further examination such as CT or MRI were X-p findings or auditory symptoms suspicious for AT or vertigo/dizziness suspicious for intracranial disease. Of five causes with AT, two with a small tumor exhibited normal findings for the internal auditory canal on temporal bone X-p. These small ATs were finally confirmed by MRI. MRI could also detect lacunar infarctions, cerebral atrophy and high jugular bulb which might be related to SNHL. These findings confirmed that MRI is very useful for detecting small ATs and suggested that MRI also reveals cerebral vascular insufficiency in patients with SNHL.

Adolescent↗
PubMed2000

[Activities of antimicrobial agents against 5,180 clinical isolates obtained from 26 medical institutions during 1998 in Japan. Levofloxacin--Surveillance Group].

The surveillance study was conducted to determine the antimicrobial activity of fluoroquinolones (ofloxacin, levofloxacin, ciprofloxacin, tosufloxacin) and other 20 antimicrobial agents against 5,180 clinical isolates obtained from 26 medical institutions during 1998 in Japan. The resistance to fluoroquinolones was remarkable in Enterococci, methicillin-resistant staphylococci and Pseudomonas aeruginosa from UTI. However, many of the common pathogens such as Streptococcus pneumoniae including penicillin-resistant isolates, methicillin-susceptible Stahylococcus aureus, Moraxella catarrhalis, the family of Enterobacteriaceae, Haemophilus influenzae including ampicillin-resistant isolates have been kept to be susceptible to fluoroquinolones. About 90% of P. aeruginosa isolates from RTI were susceptible to fluoroquinolones. In conclusion, the results from this surveillance study suggest that fluoroquinolones are useful in the treatment of various bacterial infections including respiratory infections.

Anti-Infective Agents↗
PubMed2000

A new approach to orthotopic bladder replacement using the transplanted bowel segment.

PURPOSE: When constructing an orthotopic neobladder, a short colonic mesentery may make the operation difficult. We have developed a new technique to autotransplant a free segment of intestine into the pelvis to augment the bladder. METHODS AND MATERIALS: In this animal feasibility study, we used eight female dogs to perform orthotopic bladder replacement using a transplanted bowel segment. A segment of bowel was transected and revascularized between the ileal artery of the reservoir and the internal iliac artery in the end-to-end fashion. RESULTS: Follow-up studies revealed that the bladder autoaugmentation using the transplanted bowel segment was functional and free of leakage. CONCLUSIONS: Our work in dogs demonstrates that the use of an autotransplanted segment of intestine appears to be feasible for augmenting the bladder in those cases where mechanical difficulty arises in anastomosing the urinary reservoir to the urethra. This procedure merits clinical evaluation in cases that present difficulty for completing orthotopic neobladder.

Animals↗
PubMed2000

Chromosome evolution involving Robertsonian rearrangements in Xyrichthys fish (Labridae, Perciformes).

Three Xyrichthys fish (Labridae, Perciformes), X. pavo, X. dea, and X. twistii, were cytogenetically studied. X. pavo and X. dea had 2n = 44 chromosomes, which were all acrocentric. X. twistii had 2n = 22 chromosomes consisting of eighteen meta- and submetacentric and four acrocentric chromosomes. The cellular DNA contents of X. pavo and X. twistii measured using flow cytometry were nearly equal. These results suggest that the karyotype of X. twistii evolved by decreasing the number of chromosomes by fusion events, probably Robertsonian fusion. Cytogenetic relationships among the three species were surmized on the basis of features on the karyotypes and the NOR locations. A large gap in the chromosome number between 2n = 44 and 2n = 22 is an interesting feature related to the process of chromosome evolution.

Animals↗
PubMed2000

[Autopsy case of adenoid cystic carcinoma of the trachea: endobronchial treatment improves quality of life].

A 67-year-old man presented with dyspnea on exertion. Bronchoscopic examination revealed a tumor arising from the middle portion of the trachea and extending to the right main bronchus. The pathological diagnosis was adenoid cystic carcinoma. Radiotherapy and subsequent endobronchial electrocautery were performed, and elicited a partial response. In the clinical course. Dumon and Ultraflex stents were placed in the trachea asynchronically. Brachytherapy and esophageal stent placement were also performed for tumor control in the trachea and esophagus. Autopsy revealed that the tumor had invaded the trachea and esophagus, and bacterial mediastinitis was also demonstrated. Because the tumor was successfully controlled during the following 4 years and 9 months, we concluded that endobronchial therapy such as stent placement or electrocautery is useful for maintaining good quality of life.

Aged↗
PubMed2000

Acetaminophen-induced immunosuppression associated with hepatotoxicity in mice.

We investigated the influence of acetaminophen (APAP), an analgesic and hepatotoxic agent, on the immune system in mice. The activity of serum glutamic-pyruvic transaminase was markedly increased by about 200 fold compared to that of the vehicle control following intraperitoneal injection of 400 mg/kg of APAP. In vivo antibody-producing responses to SRBC was significantly inhibited by APAP in a dose-dependent manner, while in vivo T cell-independent antibody-producing responses to TNP-Ficoll was not inhibited. The addition of thymocytes from APAP-treated mice suppressed the response to SRBC in vitro. Thymocyte blastogenesis following mitogenic stimulation with concanavalin A was also inhibited by injection of APAP. The delayed-type hypersensitivity response and mixed lymphocyte reaction, which are used to evaluate cell-mediated immunity, were also significantly reduced after treatment with APAP. These results indicate that APAP suppresses the humoral and cell-mediated immune responses at a dose that causes liver injury.

Acetaminophen↗
PubMed1999

Aortic arch reconstruction by transluminally placed endovascular branched stent graft.

BACKGROUND: Recently, thoracic aortic stent grafting has emerged as an alternative therapeutic modality for patients with thoracic aortic aneurysms and aortic dissections. However, its application has been limited to descending thoracic aortic aneurysms distal to the aortic arch. We report our initial clinical experience of endovascular branched stent graft repair for aortic arch aneurysms. METHODS AND RESULTS: Endovascular grafting with Inoue branched stent grafts was attempted for 15 patients with thoracic aortic aneurysms and aortic dissections under local anesthesia (n=14) or general anesthesia (n=1). Single-branched stent grafts were used in 14 patients, and a triple-branched stent graft in one. The branched stent grafts were delivered through a 22F or a 24F sheath under fluoroscopic guidance and implanted across the aneurysmal aortic arch. In 2 patients, the single-branched stent graft did not pass through the 22F sheath used. Complete thrombosis of the aneurysm was ultimately achieved in 11 patients (73%). Of 4 persistent leaks, 1 minor leak spontaneously thrombosed and 1 major leak was successfully treated by additional straight stent graft placement. In 1 patient, the right external iliac artery ruptured during the withdrawal of the sheath and was successfully repaired by the implantation of a straight stent graft. One patient with severe stenosis of the aortic graft section was successfully managed by additional stent deployment. Peripheral microembolization to a toe occurred in 1 patient, and cerebral infarction occurred in 1 other patient. Two patients who had failed to receive endovascular stent grafts died during an average follow-up of 12.6 months, 1 of pneumonia and the other of rupture of a concomitant abdominal aortic aneurysm. CONCLUSIONS: This report demonstrates the technical feasibility of endovascular branched stent graft repair for aneurysms located at the aortic arch. Careful, longer follow-up and further extensive clinical trials are awaited toward establishing this technique as a recommendable alternative to surgical treatment of thoracic aortic aneurysms.

Adult↗
PubMed1999

Characterization of endogenous serotonin-mediated regulation of dopamine release in the rat prefrontal cortex.

Endogenous serotonin (5-hydroxytryptamine, 5-HT)-mediated regulation of dopamine release in the rat prefrontal cortex was pharmacologically characterized using in vivo microdialysis. To increase synaptic 5-HT availability, a selective 5-HT uptake inhibitor fluoxetine was applied via the dialysis probe. Local perfusion of fluoxetine (30 and 100 microM) increased dopamine levels in a concentration-dependent manner. The fluoxetine (100 microM)-induced increases in dopamine release were abolished by pretreatment with the 5-HT(1B/1D) receptor antagonist GR 127935 (N-[4-methoxy-3-(4-methyl-1-piperazinyl)phenyl]-2'-methyl-4'-(5- methyl-1,2,4-oxadiazol-3-yl)-[1,1-biphenyl]-4-carboxamide] ) (10 and 100 microM). The facilitation of dopamine release was also prevented by selective inactivation of the mRNA encoding 5-HT(6) receptors using antisense oligonucleotides techniques. These findings suggest that not only 5-HT(1B) receptors but also 5-HT(6) receptors are associated with the endogenous 5-HT-mediated facilitation of dopamine release. In other words, 5-HT(6) receptors may play, in part, a significant role in the functional interaction between the dopaminergic and serotonergic neuronal system in the rat prefrontal cortex.

Animals↗
PubMed1999

Molecular pathologic analysis of the tonsil in HTLV-I-infected individuals.

Little is known about the role of the tonsils in HTLV-I infection. We performed molecular pathologic studies of tonsils in individuals positive or negative for anti-HTLV-I antibodies (HTLV-I-Ab) to clarify histologic characteristics of tonsils in HTLV-I infection. We collected tonsils and peripheral blood samples from patients who underwent tonsillectomy in a prospective manner. HTLV-I-Ab in serum was examined and presence of HTLV-I provirus was detected by polymerase chain reaction (PCR) in extracted DNA of both peripheral blood and tonsils. Histopathologic and immunohistochemical evaluations of tonsils were performed. HTLV-I seropositivity and PCR detection of HTLV-I provirus matched perfectly. Tonsil samples from seropositive individuals showed atrophy of the mantle zone and high numbers of T cells in the marginal zone compared with findings in HTLV-I-negative samples. HTLV-I provirus could be detected only from extracted DNA of extrafollicular areas. PCR in situ hybridization also showed positive signals in some mononuclear cells located in the marginal zone. There was a significant correlation between HTLV-I proviral load in tonsils and in peripheral blood. These results suggest the presence of characteristic histologic changes and deviated localization of HTLV-I-infected cells in the tonsils of individuals positive for HTLV-I.

Antibodies, Viral↗
PubMed1999

Electrophysiological delineation of the tachycardia circuit in atrioventricular nodal reentrant tachycardia.

BACKGROUND: The exact boundaries of the reentry circuit in atrioventricular nodal reentrant tachycardia (AVNRT) have not been convincingly defined. METHODS AND RESULTS: To define the tachycardia circuit, single extrastimuli were delivered during AVNRT to 8 sites of the right intra-atrial septum: 3 arbitrarily divided sites of the AV junction extending from the His bundle (HB) site to the coronary sinus ostium (CSOS) (sites S, M, and I) and the superior (S-CSOS), inferior (I-CSOS), posterior (P-CSOS), and posteroinferior (PI-CSOS) portions of the CSOS and the CSOS in 18 patients. The mean tachycardia cycle length (TCL) was 368+/-52 ms. Retrograde earliest atrial activation was observed at the HB site in all patients. The longest coupling intervals of single extrastimuli that reset AVNRT at sites S, M, I, I-CSOS, CSOS, S-CSOS, P-CSOS, and PI-CSOS were 356+/-51, 356+/-51, 355+/-52, 357+/-51, 318+/-47, 305+/-53, 311+/-56, and 312+/-56 ms, respectively, and the following return cycles at these sites were 368+/-52, 368+/-53, 367+/-53, 367+/-53, 407+/-66, 431+/-73, 415+/-55, and 412+/-56 ms, respectively. The longest coupling intervals at sites S, M, I, and I-CSOS did not differ from each other and were longer than those at CSOS and S-, P-, and PI-CSOS (P<0.0001). The return cycles at sites S, M, I, and I-CSOS did not differ from the TCL, whereas those at CSOS and S-, P-, and PI-CSOS were longer than the TCL (P<0.0001). CONCLUSIONS: The perinodal atrium extending from the HB site to I-CSOS was involved in the tachycardia circuit. I-CSOS was thought to be the entrance of the slow pathway.

Adult↗
PubMed1999

Effects of an interleukin-1beta analogue [Lys-D-Pro-Thr], on incomplete cerebral ischemia-induced inhibition of long-term potentiation in rat hippocampal neurons in vivo.

Although interleukin-1beta (IL-1beta) has recently been implicated in neuronal cell death in vitro and in vivo after global forebrain ischemia, the role of IL-1beta in the functional injuries, i.e. impairment of synaptic transmission, after cerebral ischemia that does not cause neuronal death in the nervous system remains unknown. To address this question, we investigated the effect of short-term incomplete ischemia without apparent neural death on hippocampal long-term potentiation (LTP) in anesthetized rats, and examined the possible role of IL-1beta as an intermediary in this effect. Short-term incomplete cerebral ischemia (10 min) was induced in halothane-anesthetized rats by bilaterally clamping the common carotid arteries. Four days after ischemia, functional injuries in neuronal transmission in the hippocampal formation were observed without significant changes in pathological studies such as neuronal cell death. The LTP elicited in both Shaffer-CA1 synapses and perforant path-dentate gyrus synapses was significantly inhibited by the short-term incomplete ischemia. This inhibition of LTP was blocked by IL-1beta tripeptide antagonist (Lys-D-Pro-Thr), suggesting that the inhibitory effect of mild ischemia on synaptic potentials and LTP may be mediated by the generation of IL-1beta. These findings have important implications for the role of IL-1beta in not only neuronal cell death but also functional injuries without cell loss, perhaps elicited by transient cerebral ischemia.

Anesthesia↗
PubMed1999

Analysis of paraaortic lymph node involvement in pancreatic carcinoma: a significant indication for surgery?

BACKGROUND: Lymph node status is a key prognostic factor for pancreatic carcinoma. The paraaortic lymph nodes are the highest level of lymph nodes that can be resected safely in the abdomen for pancreatic and other gastrointestinal tumors. The pattern of paraaortic lymph node involvement and its relation with other lymph node groups were analyzed and the significance of this information relative to surgical therapy examined. METHODS: Between 1974-1996, 99 patients with invasive ductal carcinoma of the pancreas underwent pancreatectomy at the study institution. The pattern of lymph node involvement, particularly paraaortic, was evaluated by careful pathologic review of extended lymphadenectomy specimens. RESULTS. Fifty-eight of 76 patients (76%) with carcinoma in the pancreatic head (Ph) and 19 of 23 patients (83%) with carcinoma of the pancreatic body and tail (Pbt) had lymph node involvement. Fourteen patients with Ph disease (18%) and 4 with Pbt disease (17%) had paraaortic lymph node involvement. Tumor size did not correlate with paraaortic lymph node involvement. A correlation was found between Group 13 (posterior pancreaticoduodenal lymph nodes), Group 14 (lymph nodes surrounding the superior mesenteric artery), and the paraaortic lymph nodes for Ph disease. All paraaortic lymph node metastases were located in the 16M region (the region between the celiac trunk and the inferior mesenteric artery). For patients with Pbt disease, the distribution of paraaortic lymph node metastases was the same as for those with Ph disease. Only 33% of cases of paraaortic lymph node metastases were suspected preoperatively or perioperatively. The longest survival for a patient with paraaortic lymph node metastases was 36 months and 17 months, respectively, for patients with Ph and Pbt disease. CONCLUSIONS: The paraaortic lymph nodes are frequent sites of metastasis from pancreatic carcinoma, and are difficult to evaluate preoperatively or perioperatively. This situation mandates paraaortic lymph node dissection, at least in the 16M region.

Adult↗
PubMed1999

Ofloxacin otic solution in patients with otitis media: an analysis of drug concentrations.

OBJECTIVE: To measure the concentration of ofloxacin in otorrhea, serum, and middle ear mucosa after topical administration of 0.3% ofloxacin otic solution. DESIGN: Study of 0.3% ofloxacin otic solution administered in a single dose of 0.5 mL in adults or 0.25 mL in children with chronic suppurative otitis media and perforated tympanic membrane, with serial sampling of otorrhea and serum up to 8 hours after dosing and middle ear mucosa up to 2 hours after dosing. SETTING: Three hospitals in Kagoshima, Japan. PATIENTS: Thirty-eight patients (age range, 3-81 years) with chronic suppurative otitis media and perforated tympanic membrane; 20 patients had sampling of otorrhea and serum and 18 patients (who required middle ear surgery) had middle ear mucosa and serum sampling. RESULTS: High concentrations of ofloxacin were measured in otorrhea samples taken immediately after dosing, followed by a rapid, nonlogarithmic decline. Elimination of the drug through otorrhea was believed to be related to loss from the application site with ear drainage, rather than to biologic mechanisms. Maximum concentration of ofloxacin in otorrhea was seen at the initial sampling time, 30 minutes after dosing, with concentrations measured up to the last sampling at 8 hours. Very low concentrations of ofloxacin were found in serum after topical administration of the drug. Concentrations were not detected in serum samples of most of the patients. The highest concentration measured was 10 ng/mL. Drug concentrations were detected primarily in samples obtained up to 1 hour after the dose was administered. Mucosal drug concentrations were highly variable, ranging from nondetectable to 602 pg/g. For the 6 bacterial strains isolated from the middle ear, the highest minimum inhibitory concentration of ofloxacin was covered by otorrhea drug concentrations measured at up to 8 hours after dosing in some patients. No adverse events were observed. No clinically significant adverse changes in laboratory test results or audiometric results were observed. CONCLUSIONS: Drug concentrations were high in otorrhea, very low or not detected in serum, and highly variable in middle ear mucosa. Nonbiologic loss of the drug with the ear drainage through the external auditory canal and eustachian tube was probably related to the high concentration in otorrhea samples. Drug concentrations in middle ear mucosa suggest that the drug reaches the infection site.

Adolescent↗