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Biomedical subjects

K Yamaguchi

Publications and source records attributed to K Yamaguchi.

At least 271 records · Page 15Linked to original sources
PubMed2000

The subclavius posticus muscle: a factor in arterial, venous or brachial plexus compression?

During dissection practice in 1993 and 1995 to 1999, we found an aberrant muscle which connected the first costal cartilage and the superior margin of the scapula in 12 sides (4.8%) of 11 cadavers (8.9%) among 248 sides of 124 cadavers. The muscle originated from the cranial surface of the sternal end of the first rib, ran laterodorsally, and inserted into the superior margin of the scapula. According to the origin and insertion, the aberrant muscle was considered to be the subclavius posticus (Rosenmüller, 1800). We also examined the supraclavicular region of a living subject by MR imaging to estimate the course of such an aberrant muscle. It is thought that the aberrant muscle runs on the anterior surface of the subclavian vein and crosses over the brachial plexus. Such a muscle could be considered as a possible factor causing the Paget-von Schrötter syndrome which is recognized as spontaneous or effort-related thrombosis of the axillo-subclavian vein. It is recommended to take into account the possible existence of such an aberrant muscle during the examination of patients with thoracic outlet syndrome, especially in those with symptoms of venous compression.

Brachial Plexus↗
PubMed2000

Glucose uptake by individual skeletal muscles during running using whole-body positron emission tomography.

The purpose of this study was to examine, by positron emission tomography (PET), the distribution of [18F]fluoro-deoxy-glucose ([18F]FDG) uptake by human muscles during 35 min of running. Thirteen healthy male subjects were studied, seven of whom participated in the exercise study. Running intensity was kept constant such that the subjects' heart rates were maintained at between 140 and 150 beats per minute. [18F]FDG [62.9 (14.8) MBq, mean (SD)] was injected after 15 min of running. PET imaging was started immediately after the running ended. The ratio of [18F]FDG uptake by muscles in runners to that in control subjects (r-c ratio) varied from three to six for the muscles of the foot and leg below the knee joint. The r-c ratio of the medial head of the gastrocnemius (MG) was higher than that of its lateral head (LG). The r-c ratio of the rectus femoris (RF) was lower than that of the other three muscles of the quadriceps femoris (QF). The r-c ratio of inactive muscles located above the waist was approximately 0.7. These results suggest that, during the moderate running of this study: (1) glucose uptake by muscles of the foot and leg below the knee joint clearly increases, (2) the r-c ratio differs significantly among the skeletal muscles, which act synergistically, and (3) glucose uptake by inactive skeletal muscles decreases.

Fluorodeoxyglucose F18↗
PubMed2000

Hemorrhagic pseudocyst and pseudocyst with pseudoaneurysm successfully treated by pancreatectomy: report of three cases.

Hemorrhagic pseudoaneurysm of pancreatic pseudocyst is one of the serious complications of acute pancreatitis. We successfully treated three patients who had hemorrhagic pseudocyst and pseudocyst with pseudoaneurysm by pancreatectomy. Case 1 was 43-year-old Japanese man who had had several episodes of acute pancreatitis and was diagnosed with hemorrhagic pseudoaneurysm of the splenic artery in a pseudocyst in the pancreatic tail, shown on computed tomography (CT) and angiography. Transarterial embolization (TAE) yielded hemostasis of the pseudoaneurysm, but rebleeding occurred 2 weeks after the TAE. Distal pancreatectomy and splenectomy was successfully performed. Case 2 was a 64-year-old Japanese man who presented to us with several attacks of acute pancreatitis. Imagings showed bleeding pseudoaneurysm of the transverse pancreatic artery in a pseudocyst in the pancreatic body. Because of marked stenosis in the proximal portion of the transverse pancreatic artery, TAE was unsuccessful. Distal pancreatectomy and splenectomy was performed successfully. Case 3 was a 40-year-old Japanese woman who had a history of abdominal trauma. Imagings showed bleeding pseudoaneurysm of the splenic artery in a posttraumatic pseudocyst in the pancreas. TAE of the pseudoaneurysm was unsuccessful because of the proximity of the pseudoaneurysm and the splenic artery. Distal pancreatectomy and splenectomy was successfully performed and her postoperative outcome was satisfactory. Whenever interventional radiology (IVR) is not indicated or has failed, aggressive and immediate surgical intervention should be considered for early and definitive recovery in these patients.

Acute Disease↗
PubMed2000

Potential of macrolide antibiotics to inhibit protein synthesis of Pseudomonas aeruginosa: suppression of virulence factors and stress response.

Recently we have reported that sub-minimum inhibitory concentrations (MICs) of macrolide antibiotics, such as erythromycin, clarithromycin, and azithromycin, induce loss of viability of Pseudomonas aeruginosa with longer incubation periods. In the present study we examined the effects of sub-MICs of macrolide antibiotics on protein synthesis and the expression of heat shock proteins (Gro-EL) in P. aeruginosa and the association of these factors with the viability of P. aeruginosa. In seven strains of P. aeruginosa clinical isolates, inhibition of protein synthesis was generally observed in bacteria grown on agar with sub-MIC azithromycin (8 microg/ml) at 24 h, and this was followed by loss of viability after an additional 24-h incubation. The inhibition of protein synthesis was shown in bacteria treated with sub-MICs of erythromycin and clarithromycin, but not with sub-MICs of other antibiotics examined (josamycin, tobramycin, ofloxacin, clindamycin, and ceftazidime) even at relatively high sub-MICs. In the heat shock condition (45 degrees C), strong expression of the heat shock protein Gro-EL was induced in bacteria grown on antibiotic-free medium, whereas there was a delay of such a response in bacteria exposed to 4 microg/ml of azithromycin. Reflecting these results, an abrupt reduction of viability in azithromycin-treated bacteria was observed within 3 h in the heat shock condition. Western blot analysis, using specific antibody for Gro-EL, demonstrated that erythromycin, clarithromycin, and azithromycin, at concentrations of 0.5-2 microg/ml, inhibited the expression of lower-molecular weight Gro-EL bands in the constitutive state. These results indicated that macrolides, at concentrations far below the MICs, suppressed protein synthesis in P. aeruginosa, an effect which may be associated with the inhibition of P. aeruginosa virulence and its loss of viability with longer incubation. Moreover, it is likely that the macrolides may sensitize bacteria to stresses, as these antibiotics induced alterations in a major stress protein, Gro-EL, in constitutive and inducible states.

Anti-Bacterial Agents↗
PubMed2000

A new model of pulmonary superinfection with Aspergillus fumigatus and Pseudomonas aeruginosa in mice.

We have produced a new model of pulmonary super-infection with Aspergillus fumigatus and Pseudomonas aeruginosa in immunosuppressed mice. Male ICR mice were given an intratracheal inoculation of 4 x 10(5) conidia of A. fumigatus in agar beads, and were immunosuppressed with 100 mg/kg subcutaneous injections of cortisone acetate on days 7, 9, 12, 14, and 16 after inoculation. Twelve days after inoculation, with the agar beads, the mice were challenged with the intranasal instillation of 2 x 10(6) CFU of P. aeruginosa. The survival rates of superinfected, A. fumigatus-alone, P. aeruginosa-alone, and non-infected mice were 50%, 30%, 90%, and 100% 14 days after pseudomonal infection (26 days after inoculation of A. fumigatus), respectively. In the superinfected mice, both A. fumigatus and P. aeruginosa were detected more than 10 days after pseudomonal infection (22 days after inoculation of A. fumigatus). Histopathological examination revealed peribronchial necrosis around A. fumigatus hyphae and inflammation by P. aeruginosa. This infection model in mice would be useful for studying the pathogenesis of superinfection.

Animals↗
PubMed2000

Most important lymph node information in gastric cancer: multivariate prognostic study.

BACKGROUND: In gastric cancer, the level and number of lymph node metastases is useful for predicting survival, and there are several staging systems for lymph node metastasis. The aim of this study was to compare the several lymph node classifications and to clarify the most important lymph node information associated with prognosis using multivariate analysis. METHODS: A total of 106 patients with histologically node-positive gastric cancer treated by radical gastrectomy and extended lymph node dissection (D2, D3) were studied. The level of lymph node metastasis was categorized simply as Level I nodes (perigastric, No.1-6), Level II nodes (intermediate, No.7-9), and Level III nodes (distant, No.10-16), irrespective of the tumor location. The Level II nodes included lymph nodes along the left gastric artery, common hepatic artery, and celiac trunk. RESULTS: Overall 5-year survival rate was 51%. Univariate analysis showed that 5-year survival rate was significantly influenced by the level of positive nodes (P < .01), total number of positive nodes (P < .01), number of positive Level I nodes (P < .01), and number of positive Level II nodes (P < .01), in addition to the tumor location (P < .05), tumor size (P < .05), gross type (P < .01), and depth of wall invasion (P < .01). Of these, independent prognostic factors associated with 5-year survival rate were the number of positive Level II nodes (0-1 vs. > or =2) (62% vs. 19%, P < .01) and the depth of wall invasion (within vs. beyond muscularis) (79% vs. 43%, P < .01). CONCLUSIONS: Among several staging systems for lymph node metastases, the number of positive Level II nodes provided the most powerful prognostic information in patients with node-positive gastric cancer. When there were two or more metastases in the Level II nodes, prognosis was poor even after D2 or D3 gastrectomy.

Adult↗
PubMed2000

17Beta-estradiol inhibits ovariectomy-induced expression of inducible nitric oxide synthase in rat aorta in vivo.

The objective of this study was to elucidate a role of ovarian steroid hormones in the production of immunologic nitric oxide (NO) synthases in the female rat aorta in vivo. Aortic homogenates were analyzed by using western blot with isoform-specific antibodies against endothelial NOS (eNOS) and inducible NOS (iNOS). Two weeks after ovariectomy (OVX), rats (10-week-old) were treated with 17beta-estradiol (E2) and/or progesterone (P4) for 5 days, and aortae were obtained from these rats on the following day. OVX markedly increased the levels of iNOS protein in abdominal aorta, whereas treatment with E2 or a combination of E2 and P4 inhibited the induction of iNOS in the aorta. The present findings indicate that endogeneous estrogen negatively regulates the expression of iNOS in abdominal aorta, and suggest that changes in the levels of circulating estrogen may affect vascular function.

Animals↗
PubMed2000

Maturation of taste buds on the soft palate of the postnatal rat.

Taste bud distribution on the soft palate and within three types of tongue papillae (fungiform, foliate, and circumvallate) were examined histologically in the rat at different postnatal ages. After paraffin embedding, serial sections (10 microm) were made and stained by HE, and digitized images of each section were examined. The existence of a taste pore was used to identify mature taste buds. At birth, 53% (68 of 127 observed) of the taste buds on the soft palate, but only 14% (14 of 110 observed) within fungiform papillae, contained a taste pore. One week after birth, the number of mature taste buds increased rapidly, resulting in 90% of soft palate taste buds and 80% of fungiform taste buds containing taste pores. In contrast, no taste buds with pores were observed at birth within foliate and circumvallate papillae; however, at two weeks after birth 52% (71 of 132 observed) of the foliate and 68% (180 of 267 observed) of the circumvallate taste buds examined contained taste pores. These results suggest that taste buds within the soft palate play an important role in the detection of nutrients in the neonatal rat.

Age Factors↗
PubMed2000

Spectroscopic and electrochemical properties of the Met86Gln mutant of Achromobacter cycloclastes pseudoazurin.

The mutant replacing the Met86 ligand of Achromobacter cycloclastes pseudoazurin (Ac-pAz) with Gln has been prepared and spectroscopically and electrochemically characterized. Ac-pAz has four ligands (2His, Cys, and Met) and donates one electron to its cognate Cu-containing nitrite reductase (Ac-NIR). The mutant ([Met86Gln]pAz) shows the electronic absorption and CD spectra considerably similar to those of zucchini mavicyanin (Mv) and lacquer and cucumber stellacyanins (St) having 2His, Cys, and Gln. The EPR signal of the mutant has an axial character, although those of Mv and St show rhombic signals. The findings indicate that the Cu site having Gln might be a distorted trigonal geometry. The half-wave potentials (E(1/2)) of [Met86Gln]pAz and the intermolecular electron-transfer rate constant (kET) from the mutant to Ac-NIR were determined by cyclic voltammetry at pH 7.0 and 25 degrees C. The E(1/2) is +134 mV (versus NHE) and the coordination of Gln instead of Met negatively shifts the E(1/2) of Ac-pAz (+260 mV (versus NHE)). The kET of [Met86Gln]pAz (1.2x10(6) M(-1) s(-1)) is larger than that of the recombinant Ac-pAz (7.5x10(5) M(-1) s(-1)).

Alcaligenes↗
PubMed2000

Synthesis and antitumor activity of duocarmycin derivatives: modification at C-8 position of A-ring pyrrole compounds bearing the simplified DNA-binding groups.

A series of the 8-O-substituted A-ring pyrrole derivatives of duocarmycin bearing the simplified DNA-binding moieties such as cinnamoyl or heteroarylacryloyl groups were synthesized, and evaluated for in vitro anticellular activity against HeLa S3 cells and in vivo antitumor activity against murine sarcoma 180 in mice. In addition, the stability of the 8-O-substituted analogues in aqueous solution and the conversion to their active form (cyclopropane compound) from the 8-O-substituted analogues in mice or human serum were examined. The 8-O-substituted A-ring pyrrole derivatives bearing the simplified DNA-binding moieties showed remarkably potent in vivo antitumor activity and low peripheral blood toxicity compared with the 8-O-substituted A-ring pyrrole derivatives having the trimethoxyindole skeleton in segment-B (Seg-B), which were equal to 8-O-[(N-methylpiperazinyl)carbonyl] derivatives of 4'-methoxycinnamates and 4'-methoxy-beta-heteroarylacrylates. Moreover, among 8-O-substituted analogues, several compounds can be chemically or enzymatically converted to their active form in human serum. This result indicated that new 8-O-substituted derivatives were different prodrugs from KW-2189 and 8-O-substituted analogues being the same type of prodrug as KW-2189.

Animals↗
PubMed2000

TAB2, a novel adaptor protein, mediates activation of TAK1 MAPKKK by linking TAK1 to TRAF6 in the IL-1 signal transduction pathway.

The TAK1 MAPKKK mediates activation of JNK and NF-KB in the IL-1-activated signaling pathway. Here we report the identification of TAB2, a novel intermediate in the IL-1 pathway that functionally links TAK1 to TRAF6. Expression of TAB2 induces JNK and NF-kappaB activation, whereas a dominant-negative mutant TAB2 impairs their activation by IL-1. IL-1 stimulates translocation of TAB2 from the membrane to the cytosol where it mediates the IL-1-dependent association of TAK1 with TRAF6. These results define TAB2 as an adaptor linking TAK1 and TRAF6 and as a mediator of TAK1 activation in the IL-1 signaling pathway.

Adaptor Proteins, Signal Transducing↗
PubMed2000

Presenilin-1 protein specifically expressed in Leydig cells with its expression level increased during rat testis development.

Presenilin-1, mutations of which cause the early-onset of Alzheimer's disease, was shown to be abundantly expressed in the testis as well as the brain. In spite of the high expression level of this protein in the testis, no further analysis has been undertaken. We aimed to study the distribution and developmental changes in presenilin-1 protein, and to provide clues so as to elucidate the role of this protein in the rat testis. To evaluate the specificity of the anti presenilin-1 antibody, rat presenilin-1 protein was expressed in COS-7 cells and the recombinant protein was used for western blot analysis. A positive band of approximately 20 kDa corresponding to the C-terminal fragment of proteolyzed presenilin-1 protein was observed. Using testis and brain tissue samples, a 20 kDa band was detected in both tissues suggesting a similar proteolytic process, but the expression level in the testis was higher than that in the brain. The expression level increased significantly during postnatal testis development. By an immunohistochemical analysis of the rat testis, a strong signal was observed in interstitial cells and further study with cultured TM3 murine Leydig cells revealed an abundant expression of presenilin-1 in Leydig cells. Our study suggests that presenilin-1 expression in Leydig cells may play an important role in Leydig cell function and testis development.

Animals↗
PubMed2000

Progressive cardiac dysfunction in adriamycin-induced cardiomyopathy rats.

Cardiotoxicity is a limiting factor in the treatment of cancer with adriamycin. We administered adriamycin by a method which minimizes the risk of peritonitis in an adriamycin-induced cardiomyopathy rat model. Sixty male Wistar rats were given 1 mg/kg of adriamycin intraperitoneally 15 times over a 3-week period (total dose, 15 mg/kg) to induce the cardiomyopathy model. Fifteen control rats received 10 ml/kg body wt. saline 15 times over 3 weeks. The animals were observed for 12 weeks and assessed for mortality, and cardiac volume and function was analyzed by echocardiography at 4, 8, and 12 weeks. In rats treated with adriamycin, the cumulative mortality was 35.8% while in the controls, none of the rats died. Left ventricular diameter of the systole (LVDs) was significantly increased at 4 weeks (4.5 vs. 3.3 mm; P<0.001). Left ventricular diameter of the diastole (LVDd) was significantly increased at 12 weeks (7.9 vs. 7.0 mm; P<0.01) and the % fractional shortening (FS) was significantly decreased at 8 weeks (33.4% vs. 50.0%; P<0.01) in the adriamycin-treated rats. This administration method appears to be useful for investigating the cardiac effect of adriamycin while avoiding the influence of peritonitis typically caused by an intraperitoneal injection of higher single doses of adriamycin.

Animals↗
PubMed2000

Metal coordination and mechanism of multicopper nitrite reductase.

Cu-containing nitrite reductase is a homotrimer in which a ca. 36 kDa monomer contains each of type 1 Cu (two His, Cys, and Met ligands) and type 2 Cu (three His and solvent ligands). Type 1 Cu receives one electron from an electron donor and transfers it to the reaction center, type 2 Cu. The distance between the two Cu atoms bound by the Cys-His sequence segment is 12.6 A. The intramolecular electron transfer from type 1 Cu to type 2 Cu occurs probably through this segment. The noncoordinated Asp and His residues around type 2 Cu play important roles in both the electron-transfer and the catalytic processes.

Copper↗
PubMed2000

Intraoperative radiation enhances decline of pancreatic exocrine function after pancreatic head resection.

Intraoperative radiation therapy has been introduced to improve survival rates after resection of biliopancreatic cancer. Early and late effects of intraoperative radiation on the exocrine and endocrine functions of the residual pancreas were examined in 54 patients with pancreatic head resection. Of the 54 patients, 20 underwent intraoperative radiation (A group) and the other 34 did not (B group). Fasting blood sugar level, a 120-min value of the 75-g oral glucose tolerance test, N-benzol-L-tyrosyl-p-aminobenzoic acid (BT-PABA) excretion value (a pancreatic exocrine function test), and amount of postoperative pancreatic juice drainage were compared between groups A and B at preoperative and early and late postoperative times. Fasting blood sugar level and a 120-min value of the 75-g oral glucose tolerance test (OGTT) showed no change at the early (<2 months) postoperative period of the two groups. At the late (>6 months) postoperative period, fasting blood sugar showed no alteration, while the 75-g OGTT 120-min value increased compared to the preoperative level in both groups. In the group A, the 75-g OGTT 120-min value at the late postoperative period was significantly higher than those at the preoperative and early postoperative periods (289.4 +/- 104.9 vs 193.0 +/- 58.2 mg/dl, P = 0.0198 and 289.4 +/- 104.9 vs 184.4 +/- 104.9 mg/dl, P = 0.0285). Preoperative BT-PABA excretion value was not different between the two groups. It decreased at the early postoperative period and returned to the preoperative level at the late postoperative period in both the groups. The decline of BT-PABA in group A was 23 +/- 21%, which was significantly larger than 11 +/- 24% in group B. The total amount of postoperative pancreatic juice drainage from postoperative days (POD) 4-13 in group A was about half as much as that in group B (720.8 +/- 916.4 vs 1433.8 +/- 962.1 ml, P = 0.0128). Univariate and multivariate regression analysis of factors concerning the decline of BT-PABA values at the early postoperative period showed that intraoperative radiation was a significant independent determinant. In conclusion, these results suggest that intraoperative radiation causes significant deterioration of pancreatic exocrine function at the early postoperative period. Intraoperative radiation for resectable periampullary carcinoma should be reappraised based on the decline of the pancreatic exocrine function as well as the improvement of the survival curve.

4-Aminobenzoic Acid↗
PubMed2000

Administration of bacterial lipopolysaccharide to rats induces heme oxygenase-1 and formation of antioxidant bilirubin in the intestinal mucosa.

Heme oxygenase (HO)-1, the rate-limiting enzyme in heme degradation, is induced by oxidative stress and its major end product, bilirubin, is a potent physiological antioxidant. We studied the induction of HO-1 and bilirubin production in intestinal mucosa using a rat model of sepsis. E. coli lipopolysaccharide was administered intraperitonealy to male Wistar rats and intestinal mucosa was harvested. Intestinal lipid peroxides increased significantly at 1 hr and peaked at 170% of the control value at 5 hr. GSH significantly decreased at 3 hr, reaching the nadir of 50% of the control value at 5 hr. HO-1 mRNA was maximally induced fivefold at 3 hr and HO-1 protein maximally increased to 10 times the control value at 7.5 hr. Both bilirubin and bilirubin oxidative metabolites were maximally increased at 10 hr, to 4.3 and 3.7 times the control value, respectively. These data suggest that oxidative stress in sepsis quickly induces HO-1 in intestinal mucosa and that subsequent production of bilirubin works as an antioxidant. The small intestinal mucosa is an active participant in the general response to sepsis.

Animals↗
PubMed2000

Hypoglycemic effect of cibenzoline in patients with abnormal glucose tolerance and frequent ventricular arrhythmias.

While some antiarrhythmic agents have potential hypoglycemic effects and indeed some reports of hypoglycemic adverse effect of those drugs, no systematic reports have been issued. We studied the hypoglycemic effects of cibenzoline, a class I antiarrhythmic agent. Cibenzoline succinate (150-300 mg/day) was given orally for 12 weeks to 10 patients who had ventricular premature complexes (VPCs) of >1000 per 24 hours and abnormal glucose tolerance before treatment with cibenzoline. Abnormal glucose tolerance, judged by a 75-g oral glucose tolerance test (OGTT), was defined as the response designated as "diabetic" or "borderline" type according to the criteria specified by the Japan Diabetes Society. In OGTT, the insulinogenic index (defined as the ratio of the increment of IRI [immunoreactive insulin] to that of plasma glucose at 30 minutes after a glucose load) and the sum of IRI (sigma IRI) were also determined. Holter ECG recordings, OGTT, and measurements of fasting plasma glucose IRI, and HbA(1c) were performed before and during cibenzoline treatment. Cibenzoline caused VPC reduction of >70% in 6 of the 10 patients. The drug significantly decreased fasting plasma glucose and HbA(1c) (mean +/- SD) 12 weeks after treatment, from 6.18 +/-0.92 mM/L to 5.54 +/- 1.08 mM/L and from 6.17 +/- 1.03% to 5.83 +/- 0.96%, respectively (P < 0.05). While it significantly increased fasting IRI from 4.99 +/- 1.50 to 6.51 +/- 1.47 microU/mL (P < 0.01), the insulinogenic index from 0.33 +/- 0.26 to 0.65 +/- 0.38 (P < 0.05), and sigma IRI from 168 +/- 67 microU/mL to 199 +/-46 (P < 0.05). Cibenzoline exerted a hypoglycemic effect, facilitating insulin secretion in patients with abnormal glucose tolerance and ventricular arrhythmias.

Aged↗