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Biomedical subjects

S Satoh

Publications and source records attributed to S Satoh.

At least 937 records · Page 52Linked to original sources
PubMedDate not supplied

Expression of facilitative glucose transporters in gastric tumors.

BACKGROUND/AIMS: Although cancer cells are known to have an increased rate of glucose metabolism, the complete mechanism for increased glucose uptake in tumor cells is unknown. METHODOLOGY: The presence of mRNA for 5 facilitative glucose transporter (GLUT) isoforms was evaluated by reverse transcription-polymerase chain reaction (RT-PCR) in paired samples of normal gastric mucosa and gastric tumor from 20 individuals. Expression of GLUT proteins was immunohistochemically determined in 70 resected gastric cancer specimens. RESULTS: By using RT-PCR, GLUT2 mRNA was detected in 80% of normal gastric mucosal samples, while GLUT4 mRNA was seen in only 40%, GLUT1 mRNA was not detected in normal gastric mucosa. In gastric carcinoma samples, GLUT1 mRNA was detected in 19 out of 20 cases (95%) and GLUT2, GLUT3, and GLUT4 mRNAs in all samples. By immunohistochemistry, GLUT1 protein was detected in 19% of the tumors. A majority of tumors (61%) expressed 1 or more transporter protein. The presence of GLUT1 protein in a tumor was positively correlated with the tumor's invasion into the gastric wall, lymphatics or blood vessels and with lymph node metastases. The post-operative survival of patients with tumor expressing GLUT1 protein was significantly worse than those with tumor without GLUT1 protein. CONCLUSIONS: Gastric cancer cells may acquire the ability to produce GLUT1 mRNA by malignant transformation. Increased expression of the high-affinity glucose transporters, GLUT1 and/or GLUT4, in tumor cells may drain glucose preferentially to the tumor at the expense of the tumor-bearing host.

Gastric Mucosa↗
PubMedDate not supplied

Quintuple carcinomas with metachronous triple cancer of the esophagus, kidney, and colonic conduit following synchronous double cancer of the stomach and duodenum.

A patient who had undergone radical gastrectomy for synchronous gastric cancer (T(1)N(0)M(0), stage I) and duodenal cancer (Tis, stage 0) in November 1987 was found to have esophageal cancer in November 1994, and underwent radical thoracolaparotomy at our hospital (T(1)N(0)M(0), stage I). After follow-up for about 3.5 years, renal cancer was detected in April 1998, and radical nephrectomy was performed (T(1)N(0)M(0), stage I). Two years later, in April 2000, the patient was found to have a polypoid lesion in the colonic conduit used for reconstruction after esophagectomy, and endoscopic mucosal resection was performed (Tis, stage 0). The patient remains under careful follow-up, including observation of the colonic conduit and the residual large intestine.

Adenocarcinoma↗
PubMedDate not supplied

Healing process of vascular prostheses seeded with venous tissue fragments.

Rapid neointima formation in fabric vascular prostheses seeded with autologous venous tissue fragments was examined. A piece of peripheral vein was minced into small fragments and stirred into 20 ml of saline. This tissue suspension was sieved through the wall of Dacron prostheses. The prostheses implanted in the descending aortae of dogs showed extremely rapid healing of the neointima. Endothelial cells lined the entire luminal surface within 14 days. There was no difference in the healing process between the area near anastomotic sites and the center.

Animals↗
PubMedDate not supplied

Endothelialization of vascular prostheses by transplantation of venous tissue fragments.

A method to accelerate the endothelialization of vascular prostheses by seeding venous tissue fragments was developed. A piece of peripheral vein was obtained, chopped into small fragments, and stirred into 20 ml of saline, making a tissue suspension. This suspension was sieved through the wall of a highly porous vascular prosthesis (water porosity: 3,600-4,000). The prostheses, (7 mm ID and 5.7 cm in length) seeded with tissue fragments, were implanted into the thoracic descending aortae of 20 dogs, and were removed from 1 to 371 days after implantation. Ten prostheses, preclotted with fresh blood, were used as controls. In the seeded grafts, an infinite number of endothelial cells migrated and proliferated from the fragments. These had produced numerous capillaries by 5 days after implantation that had reached and opened onto the luminal surface of the prosthesis. From these openings, numerous endothelial cells spread out and formed colonies. With the increase in the size of the colonies, the inner surface was completely endothelialized within 5 weeks. This quick neointimal formation by seeding venous tissue fragments might be applicable to several artificial organs.

Animals↗
PubMedDate not supplied

Prevention of infection in a porous tracheal prosthesis by omental wrapping.

The ideal tracheal prosthesis has to permit complete incorporation by epithelialization of the luminal surface. This is not possible with the currently available impermeable solid silicone tube. The authors developed a reinforced, porous polyurethane tubular prosthesis which has the potential for complete incorporation. However, because these prostheses are implanted in a contamined area such as the airway, they all become infected. In order to prevent infection, the authors evaluated the effect of omental wrapping in guinea pigs. The authors' tubular prosthesis was implanted subcutaneously in the abdominal area with the ends open to the air. Ten prostheses were wrapped with omentum and 10 prostheses were not. In 4 weeks, all control prostheses were infected and marsupialized. All the wrapped prostheses remained in place and were macroscopically not infected. Microscopically, all wrapped prostheses were well vascularized and were incorporated by granulation tissue, which did not occur in the prostheses of the control group. From these results the authors conclude that omental wrapping would be an effective way to prevent infection of porous tracheal prostheses in an open-to-the-air situation, and allow rapid tissue ingrowth and incorporation in the host.

Animals↗
PubMedDate not supplied

Detailed characterization of reactivities of anti-gastric cancer monoclonal antibodies to carbohydrate antigen.

Four murine monoclonal antibodies (MoAbs), KM191, KM206, KM230 and KM231, raised against gastric cancer exhibited very similar reactivities to human carcinoma cells, whereas their abilities in probing the antigen shed from the cancer cells were quite different. We found in this study that the four MoAbs reacted immunologically with the same monosialo gangliosides derived from a gastric cancer cell line by two-dimensional high performance thin-layer chromatography. When the reactivities of the MoAbs to a number of purified gangliosides or oligosaccharides were examined, the carbohydrate structure of the antigen was determined as sialyl Lea. KM231 exhibited the highest binding avidity to the oligosaccharide and the ganglioside among the four MoAbs. In a comparative study of KM231 and NS19-9, which is a widely used sialyl Lea-reactive MoAb, KM231 bound to the oligosaccharide with higher affinity and detected the antigen in tissue sections with higher sensitivity. In addition, KM231 could detect a small amount of the antigen ganglioside in human gastric normal and cancerous mucosa and in gastric cancer cell lines by HPTLC-immunostaining.

Animals↗
PubMedDate not supplied

Reduction of the antigenicity and immunogenicity of xenografts by a new cross-linking reagent.

To overcome the disadvantages of glutaraldehyde (GA), new cross-linking reagents, polyepoxy compounds (PC), were introduced and their effects on the antigenicity and immunogenicity of biomaterials were investigated. In the qualitative study, antigenicity of type I collagen in bovine arteries treated with GA or glycerol polyglycidyl ether (GPE), a kind of PC, was detected using a fluorescent antibody technique. To evaluate the immunogenicity quantitatively, DDY mice were twice immunized with homogenates of GA, GPE, or untreated dog arteries. Using their sera collected 10 and 90 days after the last immunization as primary antibodies, the dogs' peripheral lymphocytes were stained with FITC labeled anti-mouse IgG antibodies against shared antigens on arteries and lymphocytes. Percentages of stained lymphocytes were then analyzed with flow cytofluorometry. In both qualitative and quantitative studies, extremely low antigenicity and immunogenicity were shown in GA or GPE treated arteries. It is therefore suggested that GPE is an ideal cross-linking reagent for vascular and valvular xenografts and is applicable to clinical use.

Animals↗
PubMedDate not supplied

Development of an autologous connective tissue tube as a small caliber vascular substitute.

A small-caliber vascular graft with good healing properties was developed using an autologous connective tissue tube (ACTT) and in situ heparinization. ACTT is the best material for implantable grafts, but as a small-caliber vascular graft, both the high thrombogenicity and requirement for time to preparation in situ were serious problems. To overcome these difficulties, an ultrafine polyester fiber (UFPF) mesh was used for the framework of the graft. it has been shown that UFPF provides a good framework for fibroblast migration and proliferation both in vivo and in vitro. The granulomatous connective tissue tube could be constructed very rapidly and had numerous capillary blood vessels, which opened onto the luminal surface of the graft when it was implanted as a vascular substitute and provided colonies of endothelial cells. These colonies spread rapidly all over the luminal surface, and the graft developed permanent antithrombogenicity by endothelialization. The next problem was attainment of temporary antithrombogenicity of the graft before complete endothelialization. Since collagen fibrils are highly thrombogenic, the fact that ACTT collagen fibrils face the luminal surface requires greater antithrombogenicity. A new technique for binding heparin to collagen fibrils in situ was also developed. This was proved to be useful in maintaining the antithrombogenicity of the grafts (3 mm in inner diameter, 6 to 7 cm in length) in the animal studies. The graft showed rapid healing of the neonintima with endothelialization and long-term stability of the graft wall.

Angiography↗
PubMedDate not supplied

Developmental characteristics of blood flow in the middle cerebral artery in the human fetus in utero, assessed using the linear-array pulsed Doppler method.

To evaluate the physiological profile of human cerebral circulation, chronological sequences of flow velocity waveforms in the middle cerebral artery were studied using a pulsed Doppler method. Included were a total of 92 normal fetuses between 27 and 41 weeks of gestation, among which waveforms could be recorded in 81 cases (88.0%). Raw data of the waveforms were analysed by means of two indices: resistance index (RI) and pulsatility index (PI). Both RIs and PIs were calculated at 3-week intervals and were compared at two consecutive periods. Both RI and PI remained unchanged between 27 and 35 weeks of gestation. There were significant decreases in both indices between 33-35 and 36-38 weeks (P less than 0.01), and also between 36-38 and 39-41 weeks (P less than 0.05). These findings indicate that cerebral vascular resistance starts to decrease at the critical period of 36-38 weeks, after which there is a continuing decrease to term. The findings obtained using our method of assessment of fetal middle cerebral artery circulation are discussed.

Blood Flow Velocity↗
PubMedDate not supplied

Effects of nifedipine and TMB-8 on angiotensin II-induced mesenteric vasoconstriction in dogs.

The effects of a Ca2+ entry blocker, nifedipine, and a putative intracellular Ca2+ release inhibitor, 8-(N, N-diethylamino) octyl-3,4,5-trimethoxybenzoate (TMB-8), on mesenteric vasoconstriction, induced by angiotensin II, were examined in anesthetized dogs. Injection of angiotensin II (5 and 10 ng/kg) into the mesenteric artery decreased the mesenteric blood flow, which was suppressed during intramesenteric arterial infusion of TMB-8 (30 and 100 micrograms/kg/min) but not of nifedipine (0.03 and 0.1 microgram/kg/min). A higher dose of nifedipine (0.3 microgram/kg/min) only slightly attenuated the mesenteric blood flow response. Intravenous injection of angiotensin II (100 ng/kg) decreased the mesenteric and renal blood flow. Both blood flow responses were suppressed during intravenous infusion of TMB-8 (1 and 2 mg/kg/min). Intravenous infusion of nifedipine (0.1-1.0 microgram/kg/min) suppressed the renal blood flow response, whereas the mesenteric blood flow response was relatively resistant to nifedipine. The present results suggest that a TMB-8-sensitive Ca2+ movement pathway participates in the angiotensin II-induced contraction of the dog mesenteric vasculature in vivo. The Ca2+ influx through dihydropyridine-sensitive Ca2+ channels may not play a significant role in the angiotensin II-induced mesenteric vasoconstriction.

Angiotensin II↗
PubMedDate not supplied

A functional neointima with regularly arranged smooth muscle cells in a fabric vascular prosthesis transplanted with autologous venous tissue fragments.

Regular arrangement of smooth muscle cells underneath an endothelial cell layer was observed in the neointima of a fabric vascular prosthesis treated with new technology to accelerate endothelialization, i.e., transplantation of autologous venous tissue fragments in the graft wall. This finding indicated that the neointima has a vital function as the intima of the blood vessel. A canine left jugular vein was minced and stirred into 20 ml of saline containing 1,000 IU heparin. It was injected with pressure into a fabric prosthesis (4 mm inner diameter [ID], 3.5 cm in length, Water porosity: 4,000 ml) to create the tissue fragmented, heparinized graft. The graft was implanted into the same animal from which the jugular vein was taken. Forty tissue fragmented heparinized (TFH) grafts were implanted in both carotid arteries of 20 dogs and explanted from 1 hr to 400 days after implantation. In this study, the neointimae of the grafts implanted for more than 1 month are analyzed, with a focus on the arrangement of smooth muscle cells in the neointima. A circumferential arrangement of smooth muscle cells with a thin layer of longitudinally arranged cells underneath was seen in the neointimae, which resemble the arrangement of smooth muscle cells in the natural arterial wall. Some areas had a thin smooth muscle cell layer in the longitudinal direction just under the endothelial cell layer. At anastomotic sites, they ran in parallel rows in the longitudinal direction. The authors previously clarified that the smooth muscle cells arrange in parallel rows in the direction of strain caused by tensile stress.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMedDate not supplied

Small diameter vascular prostheses with incorporated bioabsorbable matrices. A preliminary study.

The authors have designed small diameter vascular prostheses with incorporated matrices that can be absorbed into a growing anastomotic neointima. First, a gelatin-heparin complex was coated on the inner surface of tubular ultrafine polyester fabrics presealed with heat denatured albumin. Second, to control the bioabsorption rate, the prepared grafts were cross-linked with polyepoxy compounds for 3 days (Group I; n = 14) or 5 days (Group II; n = 4). These grafts, 3 mm in diameter and 4 cm long, replaced the carotid arteries of nine mongrel dogs weighing 9.5-14 kg. Six of eight (75%) grafts in Group I were patent when the animals were killed 4 weeks after surgery. Doppler sound examination revealed that the remaining six were patent for 16 weeks. In Group II, three of four (75%) grafts were patent when the animals were killed 8 weeks after surgery. In both groups, scanning electron microscopic study showed neither platelet aggregation nor fibrin formation on the midportion. However, these two groups significantly differed in histology. In Group I, thin anastomotic neointima advanced over the mostly absorbed gelatin-heparin complex layer. Connective tissue was well formed around the polyester scaffold. In contrast, thick neointima advanced over the gelatin-heparin complex layer that still remained on the luminal surface in Group II. These results suggest that the gelatin-heparin complex, when cross-linked adequately, could simultaneously function as a temporary antithrombogenic surface and as an excellent substructure of an anastomotic neointima.

Anastomosis, Surgical↗
PubMedDate not supplied

Effects of nifedipine and TMB-8 on angiotensin II-induced antinatriuresis in anesthetized dogs.

A calcium entry blocker, nifedipine, or an intracellular calcium release inhibitor TMB-8, was infused into the renal artery before and during intravenous infusion of angiotensin II in anesthetized dogs. In the control period, nifedipine (0.1 microgram/kg/min) or TMB-8 (75 micrograms/kg/min) increased urine flow rate, urinary sodium excretion and fractional sodium excretion, with little change in renal blood flow or glomerular filtration rate. Angiotensin II (10 ng/kg/min) elevated blood pressure and reduced urine flow rate, urinary sodium excretion and fractional sodium excretion. In the angiotensin II infusion period, nifedipine increased urine flow rate, urinary sodium excretion and fractional sodium excretion to levels higher than those observed in the control period. TMB-8 also caused augmented urinary responses. The results suggest that the angiotensin II-induced antinatriuresis depends both on the calcium influx through dihydropyridine-sensitive calcium channels, and on the calcium release from TMB-8-sensitive calcium stores at the renal tubular sites.

Angiotensin II↗
PubMedDate not supplied

Vascular endothelial growth factor enhances vascularization in microporous small caliber polyurethane grafts.

Neoarterial regeneration in an implanted small caliber vascular prosthesis is complexly controlled by many structural and biologic factors, such as cytokines. The authors designed an artificial graft, which was prepared as follows. Segmented polyurethane tubular film (inner diameter, 1.5 mm; wall thickness, 100 microns; length, 20 mm), in which micropores (pore size, 100 microns) were fabricated by an excimer laser ablation technique, were coated with a mixed solution of photoreactive gelatin and heparin with or without cytokines (vascular endothelial growth factor [VEGF]: 5 or 50 micrograms/ml, basic fibroblast growth factor [bFGF]: 1 microgram/ml). These coated grafts were irradiated by ultraviolet light, and were implanted in aortas of rats for 4 weeks; the VEGF (5 micrograms/ml) group, n = 6; the bFGF group, n = 6; the VEGF (5 micrograms/ml)/bFGF group, n = 11; the VEGF (50 micrograms/ml)/bFGF group, n = 5; and the control group, n = 9. Control grafts were treated without cytokines. Endothelial coverage was greater for the cytokine immobilized groups (approximately equal to 50-60%) than for the control group (approximately equal to 30%). At the midportion of the triple VEGF immobilized group, many capillaries were seen in the neoarterial intima, and in the micropores, although such capillaries were rarely observed in the bFGF and control groups. Thus, impregnation of VEGF in the gelatinous layer of grafts enhanced transanastomotic tissue ingrowth and transmural capillary ingrowth.

Animals↗