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Biomedical subjects

A Yamaguchi

Publications and source records attributed to A Yamaguchi.

At least 505 records · Page 28Linked to original sources
PubMed1991

Active efflux of ofloxacin by a highly quinolone-resistant strain of Proteus vulgaris.

A clinical isolate of Proteus vulgaris, strain 881051, highly resistant to ofloxacin (MIC for ofloxacin; 800 mg/L) possessed three types of resistance mechanisms to ofloxacin. The supercoiling activity of DNA gyrase from this strain was barely inhibited by ofloxacin, the ID50 value of ofloxacin against the enzyme was 2700 times higher than that against the enzyme from a susceptible strain, P. vulgaris 08602. In the outer membrane of this resistant strain, no porin protein of 37 kDa was detectable. In the presence of carbonylcyanide m-chloro-phenylhydrazone (CCCP), we found that the accumulation of ofloxacin in the cells of strain 881051, treated with the drug, was about 40-fold higher than that in the absence of CCCP. The CCCP-induced increase in the intracellular drug was 10 and 30 times higher than those in strain 880561 (a moderately resistant strain, MIC 50 mg/L) and 08602 (a fully sensitive strain), respectively. Simultaneous treatment of the strain 881051 with ofloxacin and CCCP resulted in bactericidal synergy. These results indicated that in addition to alterations of DNA gyrase and outer membrane proteins, the active efflux, as the third mechanism, could operate the resistance of strain 881051 to ofloxacin.

Anti-Infective Agents↗
PubMed1991

Delta pH-dependent accumulation of tetracycline in Escherichia coli.

The effects of ionophores on tetracycline accumulation in Escherichia coli cells were investigated in the presence of polymyxin B nonapeptide. Accumulation was inhibited by nigericin but not by valinomycin. Tetracycline accumulation was stimulated by decreasing the pH of the medium and inhibited by the addition of magnesium ions. These results indicated that tetracycline enters cells through diffusion as a protonated form (TH2) and is accumulated as a membrane-impermeable magnesium-tetracycline chelate complex (THMg+). This noncarrier diffusion hypothesis was confirmed by the fact that tetracycline accumulated in protein-free liposomes through an artificially imposed pH difference.

Escherichia coli↗
PubMed1991

Linkage between capsaicin-stimulated calcitonin gene-related peptide and somatostatin release in rat stomach.

Calcitonin gene-related peptide (CGRP) is present in the stomach, and exogenous CGRP stimulates gastric somatostatin release. A study was undertaken to elucidate the functional linkage between CGRP and somatostatin in the stomach. Newborn Wistar rats were made CGRP deficient by intraperitoneal injection of capsaicin 2 days after birth, and then 2.5 mo later, release of CGRP and somatostatin was examined by vascular perfusion of the isolated stomach. In CGRP-deficient rats, neither the content nor basal secretion of gastric somatostatin differed from that in normal rats, and although none of several secretagogues induced CGRP secretion, the somatostatin response to glucagon was well preserved, indicating the presence of normally functioning D cells. On the other hand, arterial infusion of capsaicin significantly increased the release of not only CGRP but also somatostatin from the stomach of normal rats. In CGRP-deficient rats, however, capsaicin produced no corresponding effect. Finally, human CGRP-(8-37), a CGRP-receptor antagonist, completely inhibited the increase of gastric somatostatin induced by both rat alpha-CGRP and capsaicin infusion in normal rats. Thus the capsaicin-induced increase of somatostatin release appears to be mediated by CGRP in the stomach.

Animals↗
PubMed1991

Etiology and pathogenesis of marked elevation of serum transaminase in patients with acute gallstone disease.

From 1980 through 1988, biliary surgery was performed in 197 patients with acute gallstone disease and concomitant elevation of serum glutamic oxalacetic transaminase (SGOT) or serum glutamic pyruvic transaminase (SGPT) of over 300 Karmen units. In 137 patients, anatomic inspection and liver biopsy were performed during the acute stage of the disease. Impacted and floating bile duct stones were found in 69 (50%) and in 43 (32%) of the 137 patients, respectively. The main liver histology was necrosis of liver cells. After surgery, high serum transaminase fell rapidly with immediate recovery in 99% of the patients. In the remaining 60 patients, their signs and symptoms settled soon after initial conservative treatment and surgery was performed after an average time of 21 days. At laparotomy, impacted bile duct stones were found in 2 (3%) and liver histology revealed regeneration of liver cells. These findings suggest that marked elevation of serum transaminase in patients with acute gallstone disease might be due to an acute inflammatory liver cell injury caused by impacted bile duct stones or migrating stones, which would be transient and reversible after early resolution of the bile duct obstruction.

Acute Disease↗
PubMed1991

Immunocytochemical staining of proliferating cells in endoscopically biopsied tissues of gastric carcinomas with monoclonal antibody Ki-67.

The growth fractions in endoscopically biopsied materials from 121 patients with gastric carcinomas were determined by immunohistochemical staining with the monoclonal antibody Ki-67 and the results correlated with the histopathologic findings and clinical outcome. The Ki-67 labeling rates ranged from 4.6 to 52% (mean: 22%). A significant correlation was found between Ki-67 labeling rates of biopsied materials and those of resected specimens. The tumors showing Ki-67 labeling rates of greater than 22% are more likely to have lymph node metastasis, lymphatic invasion of serosal invasion than those with the rates below 22%. In addition, Ki-67 labeling rates were closely associated with prognosis. Tumors with high Ki-67 labeling rates (greater than 22%) were related to poor prognosis, whereas those with low Ki-67 labeling rates were associated with favorable prognosis. The immunohistochemical staining of proliferating cells in endoscopically biopsied specimens of gastric carcinomas using the Ki-67 monoclonal antibody may be useful in assessing prognosis in carcinoma of the stomach.

Antibodies, Monoclonal↗
PubMed1991

Endopyelotomy for treatment of ureteropelvic junction obstruction.

A total of 14 patients underwent endopyelotomy at our institution for treating ureteropelvic junction (UPJ) obstruction (12 primary and 2 secondary obstructions) between March 1986 and July 1989. Radiographic evaluation of the patients with a minimum follow-up of 6 months demonstrated improvement in 11, while the remaining 3 were stable. These 3 were cases with primary obstruction and 2 of them had had an associated large redundant renal pelvis. No patients exhibited evidence of increased hydronephrosis or decreased renal function. Twelve of the 14 patients had had preoperative symptoms. Complete and partial remission of the symptoms was obtained in 11 and in 1 who was radiographically stable, respectively. Thus, our success rate for endopyelotomy was 75% in primary obstruction. Successful results were obtained in all the 2 cases with secondary obstruction. There was 1 patient with an intraoperative complication (extravasation) and a late complication related to the stent. However, the problems were minor and easily corrected. Our results suggest that careful selection of cases may lead to a high success rate in endopyelotomy for treating primary UPJ obstruction.

Adolescent↗
PubMed1991

Acid phosphatase activity is detected preferentially in the osteoclastic lineage by pre-treatment with cyanuric chloride.

We previously reported a simple method to detect osteoid matrices in decalcified bone sections by pre-treatment with cyanuric chloride. We have applied this technique to identify osteoclasts and their precursors in rats. In JB-4 sections prepared from untreated bone tissues with cyanuric chloride, both acid phosphatase (ACP) and tartrate-resistant acid phosphatase (TRAP) were found not only in osteoclasts and bone marrow mononuclear cells but also in osteoblasts. In contrast, treatment of bones with cyanuric chloride resulted in staining ACP preferentially in osteoclasts and mononuclear cells adjacent to the bone surface. In the osteoclasts and most of the ACP-positive mononuclear cells, autoradiography showed calcitonin binding. Decalcification with EDTA did not affect the staining for ACP activity in bones treated with cyanuric chloride. It was possible to simultaneously identify ACP and osteoid matrix in a decalcified section. In soft tissues without treatment with cyanuric chloride, both ACP and TRAP were detected in splenic macrophages, alveolar macrophages, and proximal convoluted ducts in kidney. Neither ACP nor TRAP was found in these cell types in the tissues treated with cyanuric chloride. This procedure provides a new, simple method to identify a more restricted population in the osteoclastic lineage than that detected by TRAP staining.

Acid Phosphatase↗
PubMed1991

[Vasitis nodosa: report of two cases].

Two cases of vasitis nodosa are reported hereon. The two patients were 47 and 40 year old males with desire of refertility. They were performed vasectomy 23 and 10 years ago. They were subjected to vaso-vasostomy. During the operations, spindle shaped nodules were found in the vas deferens at the site of the previous vasectomy. Histologically, they showed focal proliferation of epithelial components forming glands, where a plentiful number of sperms were present, and this was also associated with proliferative change of smooth muscle bundles of vas deferens. Some foci of spermatic granulomas were also found. This condition was similar those of salpingitis isthmica nodosa in the fallopian tube. Vasitis nodosa should be differentiated from metastatic adenocarcinoma histologically. This condition may lead to re-canalization.

Adult↗
PubMed1991

[Correlation of p105 expression and malignancy in gastric cancers].

The expression of proliferation-associated nuclear antigen p105 of gastric carcinomas was studied by multiparameter flow cytometry and immunohistochemical technique. Content of p105-antigen in cancer cells increased with cell cycle progression, and increased more rapidly in cells in late-S phase than in cells in G0 and early S-phases. Cells in M-phase exhibited a dramatic increase in the amount of the antigen, and the amount of IF intensity of mitotic cells were approximately 5-10-fold greater than that of cells in G1- and S-phases. Immunohistochemical technique demonstrated that patients with lymph node metastasis are more likely to have high p105 positive rates than node-negative patients. The mean p105 positive rates of aneuploid tumors were significantly higher than those of diploid tumors. These results indicate that the measurement of p105 positive rates may be a powerful prognostic indicator of gastric carcinoma.

Aneuploidy↗
PubMed1991

Tissue status of epidermal growth factor and its receptor as an indicator of poor prognosis in patients with gastric cancer.

An immunohistological study of epidermal growth factor (EGF) and epidermal growth factor receptor (EGFR) was made with 157 specimens of stomach cancer. EGF stained positively in 70 specimens (45%), and EGFR in 53 specimens (34%). The cancers were classified into three groups; Group 1 with neither EGF nor EGFR staining positively (67 tumors); Group 2 with either EGF or EGFR staining positively (57 tumors); and Group 3 with both EGF and EGFR staining positively (33 tumors). The incidence rates of tumors of macroscopically infiltrative, poorly differentiated, deep invading and node-positive types were significantly higher for Group 3 than for Groups 1 and 2. The bromodeoxyuridine labeling indices (BrdU LIs) were significantly higher for Group 3 (median: 15.1%) than for Group 1 (median: 10.7%) or Group 2 (median: 11.4%). Patients with synchronous expression of EGF and EGFR (Group 3) had the poorest prognosis. From the results, it may be concluded that tumors with synchronous expression of EGF and EGFR have the highest malignant potentials and this phenomenon may cause autocrine secretion for self-replication.

Adult↗
PubMed1991

Mechanisms in passive enhancement of cardiac and renal allografts by serum from liver-grafted rats.

The ability of serum from PVG (haplotype RT1c) rats carrying long-term surviving orthotopic DA (RT1a) liver grafts (OLT serum) to enhance cardiac allografts has been confirmed and extended to renal allografts. One millilitre of OLT serum given at the time of allografting was sufficient to cause permanent acceptance of PVG.RT1a heart or kidney grafts in PVG recipients ('enhanced recipients'); the PVG.RT1a being congenic with respect to PVG, and sharing the RT1a haplotype with DA. Adoptive transfer of thoracic duct lymphocytes (TDL) from rats carrying enhanced liver grafts into irradiated recipients indicated that specific alloreactive clones had been functionally inactivated or deleted; this was accompanied by active suppression in which specific alloreactivity of normal TDL was partially inhibited. In vitro, splenic T cells from rats with enhanced grafts mediated allospecific suppression in mixed lymphocyte reaction (MLR). The serum of rats carrying enhanced grafts was able to specifically suppress MLR of the same donor/recipient combination. Thus enhancement by orthotopic liver transplantation (OLT) serum leads to cellular and serological changes in the recipient associated with maintenance of unresponsiveness. Such changes are similar to those seen in liver graft recipients themselves.

Animals↗
PubMed1991

[Alpha 2plasmin-inhibitor . plasmin complex (PIC)--useful diagnostic and prognostic parameter].

To evaluate the diagnostic and prognostic value of PIC, we compared it with the DIC score (which is calculated from platelet count, fibrinogen, FDP, and prothrombin time). We examined 182 samples from 60 patients with coaglo-fibrinolytic abnormalities. For the diagnosis of DIC, the sensitivity of PIC was significantly higher than that of DIC score (78.46% vs 43.08%; chi 2-test p less than 0.01), although the specificity of PIC was significantly lower than that of DIC score (32.48% vs 69.23%; chi 2-test p less than 0.01). For the prediction of prognosis, the peak value of PIC and DIC score during the patient's clinical course were evaluated. The non-survivors (n = 33) had significantly higher levels of peak PIC and DIC scores than the survivors (n = 27) (peak PIC: 6.1 + 9.0 micrograms/ml vs 2.2 + 3.3, p less than 0.05; peak DIC score: 4.6 + 2.4 points vs 3.3 + 2.2, p less than 0.05). The patients with a peak PIC of more than 4.0 micrograms/ml had a mortality of over 90%. These results show that PIC is a useful diagnostic and prognostic parameter.

Aged↗
PubMed1991

[A case of "postoperative erythroderma" following coronary artery bypass grafting operation].

So-called "Postoperative Erythroderma" was experienced in a 68 year-old man who received CABG for unstable angina. After a seemingly uneventful recovery, he revealed high grade fever on 13th post operative day (POD), rashes over the whole body on 15th POD and pancytopenia on 20th POD. He died of sepsis, multiple organ failure and DIC on 21st POD. Blood transfusion (concentrated red cell: 3 units) was done on operation. In this case, the rate of premature and atypical lymphocytes increased, and the ratio of OKT4 (helper)/OKT8 (suppressor) decreased. These findings of the examination suggested that there was a possibility of cell-mediated immunological depression. We considered this to be acute GVHD after blood transfusion.

Aged↗
PubMed1991

Transcatheter embolization of testicular vein for varicocele testis.

Percutaneous transcatheter embolization of the testicular vein was performed on 28 patients with angiographically proven varicocele testis. In 2 patients bilateral and in 26 only the left vein was embolized using 3-, 5-, or 8-mm stainless steel coils. All patients had clinically palpable varicoceles and male infertility. The grade of varicoceles improved after embolization in 23 of 28 cases (82%). Effective sperm count increased significantly from 34.5 +/- 44.6 to 65.1 +/- 71.0 following embolization. However, pregnancy was achieved only in one of 28 cases. Technically, the basilic vein approach was felt to be superior to the femoral vein or jugular vein approach for this procedure.

Adult↗
PubMed1991

[Study of para-aortic lymph node metastasis for advanced gastric cancer on consecutive lymph node slices].

Para-aortic lymph nodes (No. 16) from 21 patients with advanced gastric cancer who underwent extensive lymph node dissection, were sliced consecutively at intervals of 50 mu to study minute metastasis of No. 16 lymph nodes. Twenty-six of 30 metastatic lymph nodes had minute involvement, in which carcinoma cells were detected in marginal sinus of lymph node, microscopically. The rate of the metastases to No. 16 lymph nodes was 19% among N0-3 cases by conventional method (not consecutive slices). On the contrary, the percentage of metastasis to No. 16 lymph nodes by consecutive slices was 33% among N0-3 cases. Therefore, No. 16 nodes are involved in metastasis at high rate at operation and the extensive lymph node dissection including No. 16 nodes (R4) will be recommended to prevent lymph node recurrence caused by such a minute metastasis.

Aorta↗
PubMed1991

[A case report of a thrombosed mitral prosthesis diagnosed by 111In-oxine platelets scintigraphy].

The purpose of this report was to evaluate the efficacy of 111In-oxine labeled platelets scintigraphy for detection of thrombus in the prosthetic valve. A 50-year-old man underwent re-mitral valve replacement with a Björk-Shiley prosthesis because of malfunction of the xenograft in a previous operation. Almost one year later, this patient suffered from peripheral embolism and sight disturbance. There was no evidence of a thrombosed valve although it was suspected. Cineradiography showed the valve almost fully open, and there were no abnormal sounds when the valve closed. 111In-oxine labeled platelets scintigraphy was performed for the detection of thrombus in the mitral position. Hot areas of high quality in the scintigram were demonstrated in the mitral position. As a result, Björk-Shiley prosthesis was replaced with a Duromedics prosthesis. A small thrombus (10mm) surrounded by fresh tiny thrombi was found in a minor orifice of the Björk-Shiley prosthesis.

Heart Valve Prosthesis↗