Search PubMed⌕ Search

Biomedical subjects

Y Shoji

Publications and source records attributed to Y Shoji.

At least 163 records · Page 9Linked to original sources

Verapamil and cyclosporin A modulate doxorubicin toxicity by distinct mechanisms.

Cyclosporin A has been reported to enhance the sensitivity of cells displaying multiple drug resistance to anthracyclines. However, the mechanism of action of cyclosporin A in modulating drug resistance is still controversial. This study compares the effects of cyclosporin A and verapamil on doxorubicin resistance in chinese hamster ovary cells (CHRC5) using several criteria including in vitro cytotoxicity, drug accumulation, intracellular distribution by video microscopy, and nuclear DNA damage. Our results demonstrate that verapamil modulation of doxorubicin resistance was paralleled by cellular accumulation of doxorubicin, altered intracellular distribution of doxorubicin from cytoplasm to nucleus, and an increase in the formation of doxorubicin related DNA strand breaks. In contrast, the modulating effect of cyclosporin was qualitatively different. High concentrations of cyclosporin (5 micrograms/ml) increased doxorubicin accumulation and caused partial redistribution to the nucleus. However, with low concentrations of cyclosporin (1 microgram/ml) increased doxorubicin sensitivity was observed without changes in net accumulation of doxorubicin or intracellular distribution, and without enhanced doxorubicin induced DNA breakage. These results suggest that cyclosporin A can modulate doxorubicin cytotoxicity by means other than interference with the P-glycoprotein drug efflux system.

Animals↗

Function after anoabdominal rectal resection and colonic J pouch--anal anastomosis.

Twenty-eight patients undergoing anoabdominal resection of the rectum with construction of a colonic J reservoir and eight patients without a reservoir were studied 2 years after surgery. Frequency of defaecation and daytime soiling were inversely correlated with the maximum tolerable volume of the colonic J pouch. The distensibility and threshold volume of those with a pouch were significantly greater than in those without a pouch 6 months or more after stoma closure. Anal resting pressure, squeeze pressure, anal canal length and a positive inhibitory reflex were similar in both groups. Anal resting pressure, squeeze pressure and pouch distensibility correlated with frequency of defaecation in the stable phase. Pouch construction may improve the patient's quality of life in the adaptation phase.

Adult↗

Disappearance of hyperplastic polyposis after resection of rectal cancer. Report of two cases.

Since 1980, when the first description of hyperplastic polyposis of the colon appeared, 18 cases of hyperplastic polyposis have been reported in the literature. Only two of them bore colonic cancer. Here we add two cases of hyperplastic polyposis accompanying rectal carcinoma following cancer resection, in which residual hyperplastic polyps disappeared after resection.

Adenocarcinoma↗

gamma-Aminobutyric acid enhances the tone of human internal anal sphincter.

The effect of gamma-aminobutyric acid (GABA) on the human internal anal sphincter was investigated. Cumulative applications of GABA produced concentration-dependent contractions (10(-8)-10(-5) M) of the isolated human sphincter. Pretreatment with bicuculline (GABAA antagonist) turned them to relaxation. Muscimol, a GABAA agonist, induced concentration-dependent contractions (10(-8)-10(-5) M); however, baclofen (GABAB agonist, 10(-8)-10(-5) M) promoted concentration-dependent relaxation of the strips. These results suggested that both excitatory GABAA receptors and inhibitory GABAB receptors exist in the internal anal sphincter. Oral administration of sodium valproate (1600 mg/day), a GABA transaminase inhibitor, enhanced the anal canal resting pressure in 10 normal volunteers. Anal manometry showed a significant elevation in tonus without affecting amplitudes or frequencies. These results indicated that endogenous GABA, which was increased by sodium valproate, produced elevations in the anal canal resting pressure through its specific receptors in the human internal anal sphincter.

Anal Canal↗

Vipoma of the pancreas complicating ulcerative colitis.

We report a case of vipoma of the pancreas in conjunction with ulcerative colitis in a 20-yr-old woman. Twenty months after the onset of ulcerative colitis, the patient complained of watery diarrhea and was found to have an electrolyte disorder. A pancreatic tumor was detected by ultrasonography and computed tomography, along with an elevation of serum vasoactive intestinal polypeptide (VIP). The secretory diarrhea diminished dramatically, and the serum VIP level decreased into the normal range immediately after resection of the pancreatic tumor. Immunohistochemical staining revealed a pancreatic vipoma. Despite removal of the vipoma, she underwent restorative proctocolectomy and ileal J-pouch anal anastomosis 2 yr later due to progression of the ulcerative colitis. Postoperative course was uneventful, with excellent functional results. Knowledge of this rare condition accompanying ulcerative colitis may help in the management of the patient with an atypical clinical course.

Adult↗

[Serious complication of retrograde perfusion during repair of dissecting aneurysm: compression of the true lumen].

Between 1982 and 1990, 61 patients underwent the repair of dissecting aneurysm. Retrograde perfusion from the unilateral femoral artery were performed for 56 patients and the selective false lumen perfusion occurred in 3 patients. As for those 3 patients, compression of the true lumen and insufficient cerebral perfusion were suspected. Selective cerebral perfusion and antegrade systemic perfusion from the ascending aortic graft were performed. Although 2 patients took uneventful postoperative courses, 1 patient died of massive brain damage. It is very important to accomplish the means to maintain adequate cerebral circulation as soon as possible toward this fetal complication.

Adult↗

Stapled anastomosis for trans-sphincteric resection of the rectum.

We have found that in all patients who have undergone this procedure, normal defecation and complete continence are maintained. The surgical wound heals well and functional results have been uniformly good, even in instances in which only 1 centimeter of the rectum remains. This procedure may be useful for patients who are carefully diagnosed by preoperative transrectal ultrasonography in which the lower edge of the rectal tumor is within 8 centimeters of the anal verge, the tumors do not extend into the muscularis propria and there is no lymph node metastasis. Use of the CEEA stapling device can shorten the time of operation and is particularly beneficial for elderly patients and those who are at poor risk.

Aged↗

Growth and cell viability of aortic versus pulmonic homografts in the systemic circulation.

Growth characteristics and cell viability of aortic and pulmonic valve homografts in the systemic circulation were compared in a growing sheep model. Seven aortic and seven pulmonic cryopreserved homografts were implanted in the descending aortae of recipient female lambs. Of seven sheep per group, three were killed at 8 months, three at 12 months, and one at 15 months. Tissue cultures were obtained on homograft valve and root wall specimens. Male donor cells were identified by chromosome analysis. Preimplant to explant changes in pulmonic homograft external diameters at the valve annulus and sinotubular junction increased significantly more than in aortic roots. The postoperative dimensions of the distal anastomotic diameter and length of the graft increased significantly more in pulmonic than in aortic roots by time of explant. Leaflet calcification and valvular stenosis did not develop in either pulmonic or aortic homografts over the period of observation. Calcification in the root wall was significantly less in pulmonic than aortic homografts. Growth on tissue culture was obtained from over 70% of homograft specimens. Viable donor cells were demonstrated in none and 43% of aortic and pulmonic leaflets, respectively, and 71% and 57% of aortic and pulmonary arterial homograft walls, respectively. In conclusion, both aortic and pulmonic homograft valves provide freedom from calcification and stenosis in this model. Continuing expansion of pulmonic root diameters under systemic pressure might lead to late aneurysm formation. Although host cell repopulation of grafts may be advantageous, the presence of viable donor cells in leaflet tissue does not seem necessary to prevent calcific degeneration.

Animals↗

Passage of a colon 'cast' after anoabdominal rectal resection. Report of a case.

The authors report a case of the passage of a total colonic J-pouch "cast" per anus after anoabdominal rectal resection and colonic J-pouch-anal anastomosis. This occurred without development of cuff abscess and was not due to occlusion of the inferior mesenteric artery. This was successfully treated, with preservation of anal function, with resection of the colonic J-pouch by transanal approach.

Adenocarcinoma↗

Use of the argon beam electrocoagulator for performing pulmonary wedge resections.

The argon beam electrocoagulator (ABC) is a new form of electrocautery that is thought to be more effective than standard electrocautery. It has been used primarily in procedures associated with major blood loss such as liver transplantation and laparotomy for trauma. It has not been used in thoracic operations. We evaluated the safety and efficacy of the argon beam electrocoagulator for performing pulmonary wedge resections in an animal model by comparing it with standard electrocautery and suture closure. Variables used to compare the three methods of resection included perioperative blood loss, duration of chest tube air leak, and depth of necrosis and severity of inflammatory reaction in the lung at ten days and 3 weeks after resection. The argon beam electrocoagulator was as effective as standard electrocautery and suture closure in controlling air leaks, and caused less acute tissue injury than standard electrocautery. The argon beam electrocoagulator provides a safe and effective method for performing small pulmonary wedge resections, and should be evaluated in the clinical setting for this purpose.

Animals↗

Usefulness of valproate sodium for treatment of incontinence after ileoanal anastomosis.

We report on the excitatory effect of gamma-aminobutyric acid, which increased after the oral administration of valproate sodium, on anal canal resting pressure in human beings, gamma-aminobutyric acid receptors. We used this drug in order to improve continence after ileoanal anastomosis. Seventeen patients (eight with ulcerative colitis and nine with adenomatosis coli) were tested after receiving ileoanal anastomosis. The placebo showed no effect, but valproate sodium could ameliorate frequent defecation and soiling and the resulting perianal skin complications. Increasing anal resting pressure was also observed during valproate sodium administration without the amplitude, frequency of peristaltic wave, or voluntary squeeze pressure being affected. These results suggest that the subchronic administration of valproate sodium may be useful in the treatment of minor incontinence after ileoanal anastomosis.

Adult↗

[Epidural morphine as a sedative after open heart surgery: in cases of coronary artery bypass graft].

20 cases of coronary artery bypass graft (CABG) were divided randomly into 2 groups. 10 cases (Group I) received epidural catheterization between Th 6/7 at least 24 hours prior to the operation. After operation, these 10 cases were sedated with 3 mg of Morphine hydrochloride given through the epidural catheter. Other 10 cases (Group II) were sedated with 10 mg of Morphine given intravenously. Parameters of cardiorespiratory dynamics such as arterial blood pressure, pulmonary arterial pressure, pulmonary capillary wedge pressure, central venous pressure, oxygen saturation of mixed venous blood, cardiac index, doses of intravenous Nitroglycerin, Dopamine and Dobutamine, arterial blood gas analysis were measured and compared in two groups. No side effect caused by the epidural catheter was found in Group I. Parameters with significant difference in two groups were only doses of Dopamine and base excess from blood gas analysis, but these were not due to the method of sedation. Frequency of the sedation needed within 24 hours after operation was fewer, and the condition of the sedation was better in Group I. The course of postoperative management had no difference between both groups. Epidural Morphine was concluded to be an employable method of sedation after CABG.

Coronary Artery Bypass↗

Conversion of malfunctioning J pouch to Kock's pouch. Case report.

A patient with ulcerative colitis previously treated with restorative proctocolectomy and ileal J-pouch anal anastomosis had recurrent pelvic abscess and poor functional results for 3 years postoperatively. To improve the quality of life, the J pouch was converted to a Kock's pouch. The successful result implies that Kock's continent ileostomy is a good replacement for failed pelvic pouch.

Abscess↗

Studies of refractory carbides, nitrides, and borides as the thermionic emitters for electron microscopy.

Thermionic emission properties of several kinds of refractory carbides, nitrides, and borides of the transition metals in the form of powder were investigated with a newly developed measuring device and evaluated by the figure of merit defined as the ratio of the effective work function to the working temperature at which the vapor pressure becomes 1 x 10(-5) Torr. There are several materials whose thermionic emission properties are better than those of tungsten or compatible to those of tungsten among the carbides and borides, such as TaC, HfC, ZrC, LaB6, and CeB6, as judged by the figure of merit. New preparation methods for carburization, nitriding, and boriding of the wires of matrix metals and alloys were successfully developed for using these materials as the cathode of the electron microscope. Other necessary techniques such as spot welding and electrolytic etching were also developed. From the brightness characteristics, it was found that some of carbides, carbide solid solutions, and borides such as HfC, ZrC (Ta0.8-0.7Hf0.2-0.3)C, TaB2, and HfB2 are very good emitters comparable to LaB6. It is emphasized that the work functions of the carbide-solid solutions (Ta0.8Hf0.2)C and (Ta0.7Hf0.3)C, which have low rates of evaporation at high temperature, show no remarkable rise as compared with that of HfC, so that their figures of merit are better than that of HfC. Feasibility of providing good cathodes with HfC and (Ta0.8Hf0.2)C tips was demonstrated by taking high-resolution electron micrographs.

Boranes↗

Effect of sodium glycocholate and polyoxyethylene-9-lauryl ether on the hydrolysis of varying concentrations of insulin in the nasal homogenates of the albino rabbit.

Protease inhibition has been postulated to be one of the several mechanisms by which penetration enhancers promote the mucosal absorption of peptide and protein drugs. The objective of this study was to determine whether protease inhibition by Na glycocholate and polyoxyethylene-9-lauryl ether, two extensively studied enhancers, led to suppression of insulin proteolysis over a range of insulin concentrations. To this end, the rate of insulin proteolysis in nasal tissue supernatants of the albino rabbit was determined in the presence of 0.1-2% Na glycocholate and polyoxyethylene-9-lauryl ether and at insulin concentrations ranging from 5 to 100 microM. Partly due to self-association, insulin was self-stabilizing against nasal proteolysis as its concentration was raised from 5 to 100 microM. At insulin concentrations lower than 50 microM, both Na glycocholate and polyoxyethylene-9-lauryl ether reduced the rate of insulin proteolysis. By contrast, at 100 microM insulin concentration, both enhancers accelerated insulin proteolysis. Such an effect was attributed to the deaggregation of insulin by the enhancers, increasing the proportion of monomers available for nasal proteolysis. The incorporation of 0.1 mM PCMPS, a potent inhibitor of insulin proteolysis, partly overcame the accelerating effect of Na glycocholate on insulin proteolysis.

Animals↗