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Biomedical subjects

H Masuda

Publications and source records attributed to H Masuda.

At least 307 records · Page 17Linked to original sources
PubMed1993

Early and long-term effects of colectomy and endorectal pullthrough on bile acid profile.

OBJECTIVE: Although total colectomy with mucosal proctectomy and endorectal pullthrough affects two sites critical to the enterohepatic circulation of bile acids, little information is available regarding the manner in which normal digestive physiology is altered by these procedures. This study defines the early and long-term effects of colectomy and endorectal pullthrough on bile acid profile and the long-term effects on biliary lipid metabolism. SUMMARY BACKGROUND DATA: Specific changes in bile acid absorption have been reported in patients after ileal resection. Recent studies from our laboratory indicate that in the early postoperative period, colectomy with endorectal pullthrough causes a significant decrease in gallbladder bile concentrations of total bile acids, cholesterol, phospholipids, and calcium. The observation by several authors that the pouch undergoes morphologic and perhaps functional adaptation suggest that these changes may be transient and perhaps reversible. METHODS: These studies were done in an awake, unanesthetized canine model that allows periodic sampling of gallbladder bile without creation of an external biliary fistula and its associated sequelae. Animals were ultimately randomly assigned to either laparotomy and gallbladder cannulation (N = 6), or gallbladder cannulation with total colectomy and ileorectal anastomosis (N = 7), or biliary cannulation, colectomy, mucosal proctectomy and endorectal pullthrough with ileal reservoir (N = 5). RESULTS: Six weeks after operation, colectomy and ileorectal anastomosis were associated with a significant alteration in the relative composition of bile acids in gallbladder bile. These early changes were manifested by a significant (p < 0.05) increase in taurocholic acid and a concomitant decrease in taurodeoxycholic acid. These changes became even more pronounced in the ileorectal anastomosis group 12 weeks after colectomy and ileorectostomy. Although similar changes in the relative concentrations of individual bile acids occurred in the 6-week endorectal animals, bile acid profile was restored to normal by 12 weeks. CONCLUSIONS: Colectomy with ileorectal anastomosis leads to early and significant changes in bile acid profile, which persist and become even more pronounced with time. In contrast, the construction of an ileal reservoir after colectomy facilitates restoration of a normal bile acid profile. We propose that these alterations in bile acid metabolism result from adaptation of the ileal reservoir as its mucosa assumes functional characteristics of normal colon.

Adaptation, Physiological↗
PubMed1993

A case of papillary carcinoma of the thyroid with more than 30 years long-term asymptomatic pulmonary metastases.

This is a case report of a patient with thyroid cancer with asymptomatic pulmonary metastases, and without obvious progression over 34 years. The patient, a 47-year-old male, was shown to have miliary shadows on chest radiographs from the age of 13; indeed, he was temporarily treated for pulmonary tuberculosis without success. A tumour appeared in the right neck in December 1988 (at age 47). A diagnosis of lymph node metastasis of papillary carcinoma of the thyroid was made by biopsy; he then underwent total thyroidectomy with radical dissection of the neck (April 1989). However, the bilateral metastatic lymph nodes in the neck had invaded the vasculature, preventing complete dissection. Post-operative whole body 131I scintigraphy revealed diffuse intensive uptake in the bilateral lung fields, demonstrating for the first time that the pulmonary lesions were metastases of the thyroid cancer. He remains under periodic effective treatment with 131I.

Carcinoma, Papillary↗
PubMed1993

Epstein-Barr virus related gastric cancer in Japan: a molecular patho-epidemiological study.

Epstein-Barr virus (EBV) involvement in gastric carcinoma has been demonstrated by the presence of EBV genomes and EBV-encoded small RNA (EBER) in the carcinoma cells, monoclonal proliferation of EBV-infected carcinoma cells and elevated antibody titers. The present study was conducted to investigate the prevalence of EBV involvement among gastric carcinomas observed in nine Japanese cities with varying gastric cancer rates. In situ hybridization of EBER-1 was applied to paraffin sections from 1848 carcinomas observed in 1795 cases and EBV involvement was detected based on uniform hybridization in carcinoma cells. Epstein-Barr virus was detected in 6.6% of lesions and 6.7% of cases. The rate of EBV involvement did not vary significantly for each city and there was no correlation with underlying gastric cancer mortality rates. Thus, geographic variation of gastric cancer rates within Japan cannot be explained in terms of EBV involvement. Epstein-Barr virus-related gastric carcinoma is one of the most common EBV-related tumors in Japan. The involvement of EBV was significantly more frequent among males than among females, mainly for cancers occurring in the upper and middle part of the stomach, and exhibited more variation by cell type among males. These observations suggest that other factors yet to be discovered may modulate the causal role of EBV in gastric carcinogenesis.

Adolescent↗
PubMed1993

Inwardly rectifying potassium current in rat fetal and neonatal ventricular cardiomyocytes.

Whole cell and single-channel inwardly rectifying potassium currents (IK1) of freshly isolated single fetal (12 and 18 days) and neonatal (1, 5, and 10 days) rat ventricular myocytes were recorded using patch-clamp techniques. Whole cell IK1 was elicited by hyperpolarizing test pulses from a holding potential of -40 mV. IK1 densities increased markedly during heart development between fetal day 12 and until neonatal day 5; there was no further increase on neonatal day 10. Cell-attached patch recordings of single IK1 channels were employed with 150 mM K+ both in the pipette and bath solutions. Large-conductance (31 pS) K+ channels with short openings were observed both in fetal day 18 and neonatal day 5 but not in fetal day 12 cells. Only small-conductance (11 pS) channels with long openings were observed in approximately 10% of the cells on fetal day 12. The open probability of the large-conductance channels was 2.6-fold greater on neonatal day 5 than on fetal day 18. In conclusion, the increase in the IK1 density during observed heart development may be primarily due to an increase in the open probability of the IK1 channels, rather than to an increase in their number. We suggest that the small-conductance channel infrequently observed on fetal day 12 could be an immature type of IK1 channel, which disappears during development.

Animals↗
PubMed1993

Improved oral absorption of a poorly water-soluble drug, HO-221, by wet-bead milling producing particles in submicron region.

N-[[[4-(5-Bromo-2-pyrimidinyloxy)-3-chlorophenyl]amino]carbonyl]-2 -nitrobenzamide (HO-221) is being developed as an anticancer agent with a novel mode of action. HO-221 shows poor oral absorption and is only slightly soluble in water (0.055 micrograms/ml at 37 degrees C). In this study, it was shown that the reduction in particle size of HO-221 to the submicron region (0.453 microm, mean by volume) could be achieved by a wet milling in a decaglycerin monolaurate aqueous solution with small glass beads. The wet milling suspension obtained showed improved dissolution rate and oral absorption in rats. A solid dosage form could also be made from that suspension with addition of sucrose palmitate which prevented aggregation caused by the hydrophobic interaction. The solid dosage form thus obtained showed twice as much oral absorption in dogs as the preparation made by dry milling.

Animals↗
PubMed1993

Effects of hydrogen peroxide on stimulatory guanine nucleotide-binding protein in rat heart.

This study was undertaken to examine the effects of hydrogen peroxide on stimulatory guanine nucleotide-binding protein (Gs), and coupling in the beta-adrenergic receptor-Gs-adenylate cyclase system in rat heart, in vitro. Cardiac membranes were preincubated with various concentrations (0.1, 1, and 10 mM) of hydrogen peroxide at 30 degrees C for 5, 10, 30 and 60 min. Although the assay of beta-adrenergic receptors involving [3H]-dihydroalprenolol ([3H]-DHA) binding revealed that the maximal number of binding sites (Bmax) was not altered, the dissociation constant (Kd) for [3H]-DHA was increased in the presence of 1 mM and 10 mM hydrogen peroxide (control 0.68 +/- 0.16 nM, vs 1 mM H2O2 1.13 +/- 0.16, 10 mM H2O2 1.01 +/- 0.12). Conversely, no significant changes in Gs activities were observed in hydrogen peroxide-treated groups. Adenylate cyclase activity (stimulated by forskolin) was significantly reduced by 10 mM hydrogen peroxide after a 5 min preincubation period (control 277.1 +/- 19.2 pmol cAMP/mg protein/min, H2O2 230.3 +/- 14.9). The amounts of cyclic AMP produced by the stimulation of membranes with GTP, GTP+(l)-isoproterenol, guanylimidodiphosphate (Gpp(NH)p) or Gpp(NH)p+(l)-isoproterenol were significantly lower in 10 mM hydrogen peroxide-treated groups than those in controls (GTP: control 57.6 +/- 5.6 pmol cAMP/mg protein/min vs H2O2 46.4 +/- 6.9, GTP+(l)-isoproterenol: control 83.9 +/- 10.2 vs H2O2 67.7 +/- 10.3, Gpp(NH)p: control 77.5 +/- 8.8 vs H2O2 61.0 +/- 8.6, Gpp(NH)p+(l)-isoproterenol: control 105.0 +/- 13.1 vs H2O2 83.9 +/- 12.2, forskolin: control 223.2 +/- 13.8 vs H2O2 182.8 +/- 18.4).(ABSTRACT TRUNCATED AT 250 WORDS)

Adenylyl Cyclase Inhibitors↗
PubMed1993

Aortic stenosis associated with Scheie's syndrome. Report of successful valve replacement.

A 62-year-old man who had aortic stenosis associated with Scheie's syndrome (mucopolysaccharidosis [MPS], type I-S) successfully underwent aortic valve replacement. The composition of acidic glycosaminoglycans (acid mucopolysaccharides) of the excised aortic valve analyzed by high-performance liquid chromatography (HPLC) supported the diagnosis of Scheie's syndrome. This article reviews the literature on aortic stenosis in MPS, a rare inherited metabolic disorder, and discusses biochemical features and surgical repair.

Aortic Valve↗
PubMed1993

Limited adaptation in chronically hypertrophied hearts from aortic constricted rats: increased inhomogeneity in cross-sectional area of cardiomyocytes and intercapillary distance.

To study the sequential changes of myocardial structure in pressure-overloaded heart, rats were subjected to banding of ascending aorta at 8 weeks of age, and electron-microscopical morphometry was performed at weeks 1, 2, 4, 8, 16, and 24 postoperatively. Not only was the cross-sectional area of cardiomyocyte greater in banded rats but the degree of inhomogeneity increased in correspondence with development of hypertrophy. Intercapillary distance was significantly longer in banded rats than in controls. In banded rats, the distance around larger-than-normal cells (with a cross-sectional area exceeding 600 microns 2) was significantly longer than that around normal-sized cells (with a cross-sectional area under 600 microns 2) at 4, 16, and 24 weeks following surgery. Morphologically, intracellular capillaries were shown to develop; however, single or several necrotic cells were observed in 8- to 16-week banded rats and were attributed to acute ischemia. In 24-week banded rats, advanced interstitial fibrosis as well as collapsed intracellular capillaries were observed.

Acclimatization↗
PubMed1993

[Use of ultrasonography in the bladder neck suspension].

From 1988 to 1992, 78 patients with genuine stress urinary incontinence underwent bladder neck suspension under ultrasonic monitoring. Tightness of suspension was adjusted by setting posterior urethrovesical angle to approximately 90 degree by transrectal ultrasonography during operation. Urinary continence was achieved in 68 of 78 patients. In the remaining 10 patients, slight incontinence recurred within 6 months after operation. In 60 patients undergoing postoperative chain cystourethrogram, the posterior urethrovesical angles set during operation were about the same as those after operation. In 39 patients undergoing uroflowmetry under the condition that micturition volume was 200 ml or more, urinary flow rate did not decrease after operation. In 20 patients whose posterior urethrovesical angles were measured by transperineal and transabdominal as well as transrectal ultrasonography, angles measured by each ultrasonography were almost identical and neither manipulation could change the configuration of the bladder neck. The posterior urethrovesical angles set during operation were kept postoperatively and provided proper tightness of the suspension suture to achieve urinary continence without any difficulty of urination. Therefore, a posterior urethrovesical angle can be set by transperineal and transabdominal ultrasonography as well as transrectal ultrasonography. While transrectal approach provides the clearest image among the three approaches, transperineal and transabdominal approach carried out with a transabdominal convex or sectorial probe are more convenient than transrectal approach which needed a special probe.

Humans↗
PubMed1993

[Clinical studies of renal pelvic and ureteral tumors: an analysis of 611 registered cases and progress of treatment].

A review of 611 cases of renal pelvic or ureter tumor registered in Tokai Urological Tumor Registry for the past 10 years from 1980 and comparison of results between the first and latter half was made. The number of renal pelvis tumor was 347 and that of ureter tumors was 264. Clinical stages and pathological grades of the tumor were as follows; Ta, 11.9; T1, 31.8; T2, 14.4; T3, 24.3; T4, 17.6% and G1, 10.5; G2, 49.3; G3, 33.0%. Higher stages and grades were observed in the recent 5 years. Of 409 cases (66.9% in total cases) treated by total nephroureterectomy, 28.3% of the first and 49.0% of the latter half were treated adjunctively by chemotherapy. Five years relative survival rates of these two groups were 49.4 and 47.3%, respectively, suggesting no improved results. A new treatment strategy such as neoadjuvant chemotherapy or lymphadenectomy is expected to improve the prognosis.

Adult↗
PubMed1993

[Rectal involvement by prostate carcinoma: a report of three cases].

We reported 3 cases of rectal involvement by locally invasive prostate carcinoma which caused an urethrorectal fistula in case 1 and a rectal stenosis in case 2 and 3. Discriminating between primary rectal carcinoma and prostate carcinoma locally invasive to the rectum is very important because of distinct differences in treatment and prognosis. To confirm the tumor origin, tumor markers, proctosigmoidscopy, computerized tomography and biopsy with immunohistochemical staining for prostate specific antigen were useful.

Adenocarcinoma↗
PubMed1993

Effects of endothelial denudation in flow-induced arterial dilatation.

The effects of endothelial denudation of the flow-induced arterial dilatation in the rabbit common carotid artery (carotid) were studied. After endothelial denudation with a 3-French balloon catheter, the left carotid was made arterio-venous (A-V) fistula to the left external jugular vein in four adult male rabbits (3-4 kg). Five rabbits which were given A-V fistula without denudation were used as controls. Blood flow rates, luminal dimensions, hemodynamic parameters and morphology were studied after 1 week. In spite of a significant increase of blood flow, the lumen diameter of the left carotid with denudation was significantly smaller than that without denudation. The assumed wall shear stress in the left carotid with denudation was significantly higher than in that without denudation. In the denuded segment, the internal elastic lamina and media were preserved with no or slight intimal thickening, composed of mononuclear cell proliferation; however, there were frequent disruptions of the internal elastic lamina in the non-denuded left carotid. We consider that flow-induced arterial dilatation occurs when the endothelial lining is preserved.

Animals↗
PubMed1993

[Experimental study on intraoperative irradiation for pancreatic cancer: histological and nutritional changes in early phase after high dose irradiation].

For the treatment of pancreatic head cancer, pancreatoduodenectomy is followed by the intraoperative radiation therapy (IORT). The present dose adopted ranged 20 to 30 Gy, however the dose is believed to be insufficient for local control of adenocarcinoma cells. In this study, high dose IORT was performed using rabbit, so histological and nutritional changes were evaluated. Rabbits were divided in three groups; 30 Gy, 50 Gy, 80 Gy. The radiation was performed with electrons focusing base of cranial mesenteric artery (SMA in human). The rabbits were sacrificed at intervals ranging from immediately after to 4 weeks following irradiation. The earliest evidence of histological changes was the loss of endothel, although it was repaired within 1 week. Fragmentation and reduplication of internal elastic lamina were observed after 1 week, however the degree was not dose dependent. Damages of the media was observed in 50 and 80 Gy groups. That is, focal degeneration of smooth muscle cell was demonstrated in 50 Gy group and medial necrosis in 80 Gy group. Degeneration of ganglion cells was observed and its severity was dose dependent. In 80 Gy group, diarrhea occurred more frequently compared with the other groups and body weight loss couldn't recover within 4 weeks. It is concluded that, since necrosis of aortic media and marked degeneration of ganglion cells are inevitable in 80 Gy group, IORT dose should be increased within 50 Gy.

Animals↗
PubMed1993

[A case of bilateral ectopic ureter in a male].

A 7-year-old boy was admitted for recurrent pyelonephritis. Intravenous pyelography IVP showed right hydronephrosis and normal left kidney and ureter. Cystourethroscopy revealed no ureteral orifices in the bladder but bilateral ureteral openings adjacent to the seminal colliculus. Right retrograde pyelography showed severe hydroureter and hydronephrosis. The diagnosis was bilateral ectopic ureteral opening into proximal urethra. His abnormality of ureteral opening was classified as type II in Thom's classification. Bilateral ureterocystoneostomy was performed. Only 3 cases of bilateral ectopic ureter in males have been reported in the Japanese literature.

Child, Preschool↗