Biomedical subjects

Y Hamada

Publications and source records attributed to Y Hamada.

At least 19 recordsLinked to original sources

PubMed1992

Randomized adjuvant trial to evaluate the addition of tamoxifen and PSK to chemotherapy in patients with primary breast cancer. 5-Year results from the Nishi-Nippon Group of the Adjuvant Chemoendocrine Therapy for Breast Cancer Organization.

BACKGROUND: A randomized adjuvant trial was conducted from October 1982 to January 1985 to evaluate the addition of tamoxifen (TAM) to combination chemotherapy with perioperative mitomycin C (MMC) and ftorafur (FT) for patients with estrogen receptor (ER)-positive tumors and the addition of PSK, a biologic response modifier, to MMC+FT chemotherapy for patients with ER-negative tumors in operable Stage IIA, IIB, and IIIA cancer. The doses used were 20 mg of oral TAM daily, 600 mg of oral FT daily, and 3 g of oral PSK daily for 2 years. Intravenous MMC (13 mg/m2) was given on the day of operation. METHODS: A total of 967 patients were entered and randomized by stratification based on ER status and staging (1978 International Union Against Cancer [UICC] criteria at the time of trial execution). Of 967 patients, 914 (94.5%) were evaluable. At 5-year follow-up, significant prolonged overall survival (OS) and relapse-free survival (RFS) times were seen with the addition of TAM in patients with ER-positive and Stage IIIA T3N0 cancer (1987 UICC-American Joint Committee on Cancer [AJCC] criteria); however, no significant survival benefit from TAM was seen in patients with ER-positive and Stage IIA T2N1 cancer. There was no significant difference between regimens, with or without PSK, in patients with ER-negative disease. RESULTS: Results of subset analyses suggested a benefit from TAM in postmenopausal patients with ER-positive and Stage IIA T2N1 cancer and a benefit from PSK in patients with node-negative, ER-negative, and Stage IIA T2N1 cancer. CONCLUSIONS: The 5-year results of the current trial showed a survival advantage by the addition of TAM to chemotherapy in patients with ER-positive and Stage IIIA T3N0 cancer.

Adjuvants, Immunologic↗

PubMed1992

Endocrine cells and prognosis in patients with colorectal carcinoma.

Using chromogranin (CG) immunohistochemical staining, the prognostic significance of endocrine differentiation was investigated in 212 patients with primary colorectal adenocarcinoma (including 6 patients with mucosal carcinoma). CG-immunoreactive cells were found to be an integral component of the tumor in 67 of 206 patients (32.5%, excluding mucosal carcinoma). The intracellular localization of CG in the CG-immunoreactive cells in cancer tissue was completely different from that in the normal endocrine cells of the large bowel. In addition, morphologic changes such as nuclear hyperchromasia and pleomorphism also indicated that the CG-immunoreactive cells in the cancer tissue were malignant. The tumors were divided into three groups based on the frequency of CG-immunoreactive cells: Group I (n = 139), negative; Group II (n = 38), less than 1 positive cell/mm2; and Group III (n = 29), more than 1 positive cell/mm2. No correlation was observed between CG-immunoreactivity (CG-IR) and tumor location, grade, depth of invasion, or stage, regardless of lymph node involvement. However, patients with numerous endocrine tumor cells (Group III) had a significantly worse prognosis compared with patients without endocrine cells (Group I) (multivariate Cox's model, P less than 0.01). Similar findings were observed in patients with node-negative tumor (multivariate Cox's model, P less than 0.05). These results indicated that the neuroendocrine differentiation is an independent prognostic factor and that CG-immunohistochemistry is useful for detecting a subgroup with a worse prognosis among patients with colorectal cancer.

Biomarkers, Tumor↗

PubMed1992

Acute effects of cholestatic and choleretic bile salts on vasopressin- and glucagon-induced hepato-biliary calcium fluxes in the perfused rat liver.

The effects were investigated of the choleretic bile salt glycoursodeoxycholate (G-UDCA) and of the cholestatic bile salt taurochenodeoxycholate (T-CDCA) on changes in perfusate Ca2+, glucose and oxygen and in bile calcium and bile flow induced by the administration of (a) vasopressin, (b) glucagon and (c) glucagon plus vasopressin together to the perfused rat liver [Hamada, Karjalainen, Setchell, Millard & Bygrave (1992) Biochem. J. 281, 387-392]. G-UDCA itself increased the secretion of calcium in the bile several-fold, but its principal effect was to augment each of the above-mentioned metabolic events except glucose and oxygen output; particularly noteworthy was its ability to augment the 'transients' in bile calcium and bile flow seen immediately after the administration of vasopressin with or without glucagon. T-CDCA, by contrast, produced opposite effects and attenuated all of the parameters measured, and in particular the transients in bile calcium and bile flow. The data provide evidence of a strong correlation between calcium fluxes occurring on both the sinusoidal and the bile-canalicular membranes and that all are modifiable by glucagon, Ca(2+)-mobilizing hormones and bile salts.

Animals↗

PubMed1992

Concomitant stimulation by vasopressin of biliary and perfusate calcium fluxes in the perfused rat liver.

Changes in perfusate Ca2+ (measured with a Ca(2+)-selective electrode) and changes in bile calcium (measured by atomic absorption spectroscopy) were continuously and simultaneously monitored after infusion of (a) vasopressin, (b) glucagon and (c) both vasopressin and glucagon together to the perfused rat liver. Also monitored were perfusate glucose and oxygen concentrations and bile flow. Vasopressin induces a sharp, transient, pulse of increased bile flow and increased bile calcium within 1 min of infusion, concomitant with rapid changes in perfusate Ca2+ fluxes, glucose output and oxygen uptake. This is immediately followed by a decrease in both bile flow and bile calcium for as long as the hormone is administered. Changes induced by glucagon are a relatively slow onset of perfusate Ca2+ efflux and oxygen uptake, but rapid glucose output, and a small but significant and transient decrease in bile flow and bile calcium which, despite the continued infusion of the hormone, spontaneously and rapidly returns to normality. However, the greatest responses are observed after co-administration of both hormones. Coincident with the augmented perfusate Ca2+ fluxes (influx) seen in earlier work, there occurs within 1 min of vasopressin infusion a sharp increase in bile secretion and bile calcium greater in magnitude than that produced by vasopressin alone. Immediately thereafter bile secretion and bile calcium decline below basal values and remain there for as long as the hormones are administered. Glucagon and vasopressin therefore each have opposing effects on bile flow and bile calcium. However, the action of vasopressin is enhanced by the prior administration of glucagon. The data thus reveal features about the actions of glucagon and Ca(2+)-mobilizing hormones on bile flow and bile calcium not previously recorded and provide a novel framework around which the whole issue of hepato-biliary Ca2+ homoeostasis can be assessed in normal and diseased liver.

Animals↗

PubMed1992

Molecular conformation of ascidiacyclamide, a cytotoxic cyclic peptide from Ascidian: X-ray analyses of its free form and solvate crystals.

In order to investigate the conformational variation of ascidiacyclamide, a cytotoxic cyclic peptide from marine tunicate Ascidian, single crystals were prepared from ethanol and aqueous ethanol solutions as its free form (crystal I) and H2O/0.5 C2H5OH solvate (crystal II), respectively, and were determined by the x-ray diffraction method. Crystal I showed a pseudo C2-symmetric saddle-shaped rectangular conformation. Similar conformations were also observed in crystal II, where there were two crystallographically independent C2-symmetric molecules (named Mol-A and -B) per asymmetric unit. Mol-A and -B included H2O and H2O/C2H5OH solvents within their ring structures, respectively. These water and ethanol molecules were located on the crystallographic dyad axes, and were stabilized by the van der Waals contacts (including hydrogen bonds) with the polar-ring N atoms and nonpolar D-Val side-chain atoms. The conformational characteristics of ascidiacyclamide and its fluctuation/variation were discussed based on the present and previously reported x-ray results.

Animals↗

PubMed1992

Osteofibrous dysplasia of the tibia treated by bracing.

Osteofibrous dysplasia of the tibia in children will commonly recur after surgical resection. The use of a leg brace until puberty offers a useful method of conservative management. Seven female patients, age three months to nine years at the time of brace treatment, have been followed for 3.5 to 18 years, an average of nine years, with evidence of satisfactory healing of the lesions in all. Three of the cases had recurred after surgery, two with fibular grafts and one required leg lengthening. The use of a brace to control bowing of the tibia while awaiting spontaneous regression is advised until epiphyseal closure.

Braces↗

PubMed1992

The healing of flexor tendons in chickens.

The healing of flexor tendons was studied in chickens using transmission electron microscopy. After resecting the flexor sheath between the proximal and distal pulleys in zone II, the profundus tendon was severed and sutured. Intermittent passive motion was carried out 35 times daily immediately afterwards. The chickens were sacrificed at 3, 6 and 9 weeks. In vivo healing was shown to be much more rapid than in in vitro studies. There was marked proliferation of endoplasmic reticulum and phagocytosis at 3 weeks, collagen synthesis at 6 weeks and remodelling at 9 weeks. Healing was by a combination of extrinsic and intrinsic mechanisms.

Animals↗

PubMed1992

Intra-operative screw trimming in direct screw fixation of the odontoid process fracture--technical note.

For a satisfactory direct screw fixation of fractures of the odontoid process it is necessary to use a screw of the proper total length and thread length, but such an optimal ready-made screw is not always available. The authors describe a technique of intra-operative screw trimming using a high-speed diamond drill. This adjustment is easily and quickly performed. It enables the screw to act as a compression screw, which facilitates fusion of the fractured surfaces.

Bone Screws↗

PubMed1992

Inhibition of 7,12-dimethylbenz[a]anthracene-induced lipid peroxidation and mammary tumor development in rats by vitamin E in conjunction with selenium.

The effects of combined dietary vitamin E supplementation and a relatively low increase in selenium levels on 7,12-dimethylbenz[a]anthracene (DMBA) induction of lipid peroxidation in the short term and development of mammary tumors in the long term were investigated in female Sprague-Dawley rats. Control animals were fed the basal diet (20 mg/kg vitamin E and 0.6 mg/kg selenium) throughout the experiment. Three other groups received a high vitamin E diet (235 mg/kg vitamin E and 0.6 mg/kg selenium) at different times, the first two from three weeks after DMBA treatment and the other throughout the experiment. When the vitamin E diet with selenium supplementation was applied until three weeks after DMBA or until the termination of the experiment, tumor yields (tumors per rat) were significantly inhibited compared with the control group. On the other hand, delaying the supplementation of vitamin E until three weeks postcarcinogen produced no prophylactic effect. The elevation of lipid peroxidation levels observed immediately after DMBA administration was also significantly inhibited in both mammary fat pads and livers of animals in the high vitamin E group. It was therefore concluded that the inhibitory effect of vitamin E in combination with selenium on tumorigenesis might be causally related to reduction of carcinogen treatment associated with lipid peroxidation, the latter presumably playing an important role in DMBA-induced mammary carcinogenesis.

9,10-Dimethyl-1,2-benzanthracene↗

PubMed1992

Mucosal immune response to RDEC-1 infection: study of lamina propria antibody-producing cells and biliary antibody.

Infection of rabbits with Escherichia coli RDEC-1 is a useful model for diarrheal disease caused by mucosally attaching E. coli. Understanding of the protective immunity induced by RDEC-1 infection in rabbits should provide information useful in the design of vaccines for protection against this infection and other mucosally attaching organisms as well. Thus, to define the time course and location of specific immunoglobulin A secretion in relation to bacterial colonization during primary RDEC-1 infection, we infected rabbits with RDEC-1, which express AF/R1 adherence pili, and compared sites of anti-AF/R1 antibody-containing cells in the intestinal mucosa with the sites of luminal colonization and mucosal attachment of RDEC-1. Also, anti-AF/R1 antibodies in intestinal fluids and bile were measured by enzyme-linked immunosorbent assay, and attachment sites of RDEC-1 to the intestinal epithelium were determined by immunohistochemical examination. Anti-AF/R1 pilus antibody-containing cells were most numerous in the proximal intestine (duodenum and jejunum). In contrast, both luminal colonization and attachment of RDEC-1 to epithelial cells were densest in the distal intestine (cecum and colon). Anti-AF/R1 antibodies were present in approximately equal amounts in fluids collected from all levels of the gut after week 1 postinfection. Anti-AF/R1 antibody levels in undiluted bile exceeded those in gut flushes by at least 2 orders of magnitude. Loss of RDEC-1 attachment to epithelial cells preceded resolution of diarrheal illness despite the presence of large numbers of organisms in the intestinal lumen. Our studies indicate that during RDEC-1 infection (i) sites of greatest mucosal anti-AF/R1 antibody secretion are proximal to sites of maximal RDEC-1 luminal colonization and attachment, (ii) bile is a major source of specific antibodies in the intestinal lumen, and (iii) interference with RDEC-1 attachment to epithelial cells may permit resolution of disease.

Animals↗

PubMed1992

Pathology and angiographical studies on urogenital organ system induced by idiopathic hemorrhage in male E1 mice.

Urogenital organ system induced by idiopathic hemorrhage in sudden died male E1 mice were investigated macro- and histopathologically and angiographically. The mortality of the male E1 mice with brief life span was 85% during observation period for 33 weeks, and about half of the male E1 mice died between 10-week-old and 20-week-old. In all dead mice, urine retention was prominent, and the seminal vesicle or the coagulating gland, especially the bulbocavernosus muscle had severe hemorrhage. There was coagulated blood mass in the urethral lumen and the lumen of the seminal vesicle and the coagulating gland. Further, in pars spongiosa, coagulated blood mass occupied the most area of the corpus spongiosum penis and corpus cavernosum penis with severe hemorrhage. Angiographically, the penile artery in not affected male E1 mice was thinner than that in control mice.

Angiography↗

PubMed1992

[Developmental study of the ventral scent gland of the Mongolian gerbil].

Male and female in bred Mongolian gerbils aged 4, 5, 10, and 20 weeks were examined for the presence of a ventral scent gland macroscopically and histologically. It was found in about half of the gerbils aged 4 weeks and in all of the gerbils aged over 5 weeks. In adult male gerbils it weighed three times as much as in females. The ventral scent gland exhibited a sebaceous-like structure which consists of giant glandular cells with small vacuoles in the cytoplasm and the glandular cells displayed eosinophilic bodies contained within a duct, which are extruded through the lumen as holocrine-type secretion.

Age Factors↗

PubMed1992

Simulation of the profile of water, NaCl, and urea transport in the countercurrent multiplication system between thin ascending limb and inner medullary collecting duct.

We simulated the profiles of water, NaCl, and urea transport in the countercurrent multiplication system between thin ascending limb (TAL) and inner medullary collecting duct (IMCD) by a mathematical model consisting of three compartments (TAL, IMCD, and CNW [capillary network]), using phenomenological coefficients for hamsters. They are separated by two membranes with distinct permeability properties. The primary driving force which generates "single effect" has a lower reflection coefficient for urea than for NaCl in IMCD. The difference in urea and NaCl concentrations between CNW and IMCD provides an effective osmotic driving force which is favorable for water absorption from IMCD without physicochemical osmotic gradient. The entry of water in the CNW reduces the concentration in CNW and generates the concentration gradients which are favorable for these solutes to diffuse out of TAL. Thus, the fluid in IMCD is concentrated and that in TAL is diluted. The results of simulation showed that the concentration gradients were generated along the medullary axis, resulting in excretion of hypertonic urine. In addition, we examined effects of changes in phenomenological coefficients of IMCD on this concentrating system. Decreases in permeability and in reflection coefficient for urea and increase in hydraulic conductivity increased the osmotic gradients along each compartment.

Body Water↗

PubMed1992

[Mitral valve replacement in a patient with hereditary hemorrhagic telangiectasia].

A 46-year-old female with mitral insufficiency complicated by hereditary hemorrhagic telangiectasia (Osler's disease) underwent successfully mitral valve replacement. The patient had a history of repeated large-volume nasal bleeding. Mitral valve replacement using a xenograft was safely performed with various attempts for preventing abnormal postoperative hemorrhage.

Bioprosthesis↗

PubMed1992

[Fresh fracture of the odontoid process treated with direct screw fixation; a case report].

A case of a fresh type II fracture (Anderson & D'Alonzo) of the odontoid process treated with direct screw fixation is reported. A 52-year-old man complained of severe neck pain following a hit on his forehead incurred in a falling accident. Neurological examination was normal. Cervical spine x-ray films and axial CT scans revealed a fracture at the base of the dens. It was slightly oblique leftup and rightdown, and the dens fragment was displaced 3mm lateral to the right. One week after the injury, this odontoid fracture was directly fixed with a compression screw by an anterior cervical approach. Immediately after the operation, his neck pain disappeared. He had only 4 days of bed rest and 2 months of external immobilization with a simple neck collar. He returned to his previous job 2 months after surgery without any limitation of his neck movement. At follow-up examination 16.5 months after the operation, x-ray films demonstrated complete fusion of the fracture and no problem about the screw such as displacement or breakage. Direct screw fixation of an odontoid fracture via a transcervical approach was thought to be a reasonable method of treatment. For proper assembly of this method, the following two points are particularly recommended: a screw insertion perpendicular to the fracture plane and the use of an optimal screw with both the desired total and thread lengths.

Bone Screws↗

PubMed1992

[Effects of dobutamine and isoproterenol on systemic hemodynamics and myocardial metabolism in children after open heart surgery].

The purpose of this study is to know the effects of Dobutamine (DOB) and Isoproterenol (ISP) on the systemic hemodynamics and myocardial metabolism in the acute phase after open heart surgery in children. Twelve patients with congenital heart disease were administered 5 and 10 micrograms/kg/min (gamma) of DOB, then 0.005 and 0.01 gamma of ISP, and the systemic hemodynamic and metabolic data were taken before and after the administration of the drugs. DOB: DOB increased HR and SVI, so CI rose up markedly. The systolic, diastolic and mean blood pressure also rose up after both doses. CVP and PCWP were depressed at both dosage levels. SVRI and PVRI did not show an appreciable change. ISP: ISP increased HR, CI and systolic blood pressures significantly. On the other hand, SVRI, PVRI and PCWP were decreased at both dosage levels. Myocardial metabolism: The two drugs tested did not exhibit any effect on the progress of anaerobic myocardial metabolism. The myocardial oxygen uptake rate was decreased with DOB and ISP. These phenomena probably suggest that DOB and ISP dilate the coronary vascular bed. From the above data, the following effects can be expected by the use of each drug after open heart surgery in children; 1) powerful inotropic and chronotropic action by DOB, and 2) chronotropic action and after-load reduction by ISP.

Anaerobiosis↗

PubMed1992

[Intra-atrial implantation of mitral valve prosthesis in 2 patients with active infective endocarditis complicated by mitral annular destruction].

This is a report of two patients with extensive destruction of the mitral annulus due to active infective endocarditis. Patient 1 was a 66-year-old female and the patient 2 was a 59-year-old male. In both patients medical therapy had failed to control endocarditis and emergency mitral valve replacements were carried out. At the operation special surgical techniques were necessitated, since insertion of artificial valves in the annulus was impossible because of the lack of the annular tissue due to destruction and excision. On the posterior commissure side, mitral valve prosthesis were sutured to the left atrial wall just above the anatomical mitral ring. Furthermore, in patient 2, a bovine pericardium collar attached to the prosthetic valve was sutured to the left atrial wall to secure fixation of the prosthetic valve. The postoperative courses were uneventful in both patients. This technique seems to be useful in patients with mitral annular destruction.

Aged↗

PubMed1992

[Bicuspid aortic valve with sudden onset of aortic insufficiency due to rare causes: report of two cases].

This report describes two cases of aortic valve replacement which was warranted by the suddenly developed aortic regurgitation due to a congenitally bicuspid aortic valve. Aortic insufficiency was caused by the rupture of the strand which lifted a larger cusp to the aortic wall in one, and by the perforation of valvular aneurysm in another. Reviewing the literature these types of aortic insufficiency are rarely reported.

Acute Disease↗