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Biomedical subjects

S Satoh

Publications and source records attributed to S Satoh.

At least 901 records · Page 50Linked to original sources
PubMedDate not supplied

Pressure-length loop in the ischemic segment during left circumflex coronary artery stenosis and its modification by afterload reducing in excised perfused canine hearts.

By using excised perfused heart preparations, we investigated the regional myocardial functions in the presence of a flow-limiting coronary stenosis of the left circumflex coronary artery (LCX) (approximately low reduction of pre-ischemic control), as well as global cardiac functions during afterload reducing, while keeping left ventricular end-diastolic pressure (LVEDP) and heart rate constant. After inducing the LCX stenosis, cardiac output (CO), peak left ventricular pressure (peak LVP) and stroke work (SW) decreased from pre-ischemic control values, i.e., 81.1 +/- 3.2%, p less than 0.005, 88.1 +/- 3.8%, p less than 0.02 and 72.2 +/- 5.7%, p less than 0.005, respectively (n = 7), whereas pressure-length (P-L) loop areas changed as follows; ischemic control values of the left anterior descending coronary artery (LAD) and LCX regions were 96.6 +/- 6.0%, n.s. and 72.6 +/- 9.0% of pre-ischemic control, p less than 0.02, respectively. Following afterload reducing with LCX stenosis, CO increased gradually, while the ischemic regional function started to further aggravate, and the initial point of further ischemic aggravation obtained in this experiment occurred at 63.5 +/- 6.9 mm Hg of mean aortic pressure (AoP). These results suggested that the increase of total cardiac function such as CO following afterload reducing was probably induced at the expense of aggravated regional ischemia. Therefore it was concluded that the treatment of ischemic myocardium by reducing afterload pressure should be done very carefully.

Animals↗
PubMedDate not supplied

Extended lid-splitting surgery of marginal eyelid defects.

The technique of extended lid-splitting surgery is described. This procedure was used to repair marginal defects of the lower and upper lid, and provided postoperative results that were excellent both functionally and cosmetically, principally because the technique allowed the anatomical structures to be maintained.

Blepharoplasty↗
PubMedDate not supplied

Characteristic of analgesia induced by noncatecholic phenylethylamines in mice.

Using hot plate method, analgesia induced by noncatecholic phenylethylamines, phenethylamine, phenylethanolamine and amphetamine, was inhibited by naloxone, reserpine, apomorphine and p-chlorophenylalanine, while potentiated by haloperidol. These results suggest that phenylethylamines induced analgesia involves central dopaminergic and serotonergic neurons and endogenous opioid peptides. The blockade of dopaminergic neurons enhanced and the inhibition of serotonergic neuron activity or the stimulation of dopaminergic neurons attenuated the phenylethylamines induced analgesia. Using rat hind paw pressing or tail flick test, analgesia induced by electroacupuncture in which Hoku points were electrically stimulated through stainless steel needles was enhanced by phenylethylamines, haloperidol while attenuated by naloxone, reserpine, apomorphine and p-chlorophenylalanine. Thus the analgegic characteristic of phenylethylamines closely resembles that of electroacupuncture.

2-Hydroxyphenethylamine↗
PubMedDate not supplied

Role of the efferent and afferent vagus nerve in the development of ventromedial hypothalamic (VMH) obesity.

Hyperactivity of the vagus nerve and hypoactivity of the sympathetic nerves after VMH lesions both cooperatively contribute to the development of VMH obesity, mainly through hyperinsulinemia. Recently it has turned out that we should discriminate the role of the efferent vagus from that of the afferent vagus in the pancreatic hormone secretion. The hepatic branch is the main pathway of afferent fibers in the vagus, while the celiac (pancreatic) branch is the main pathway of efferent fibers. We investigated the role of the afferent and efferent vagus on the development of VMH obesity using the sectioning of the hepatic and celiac branch. Celiac vagotomy decreased insulin secretion and food intake, while hepatic vagotomy did not change them. The results suggested that the efferent vagus plays the main role in the development of VMH obesity, while the role of afferent vagus seems less apparent.

Afferent Pathways↗
PubMedDate not supplied

Gene structural analysis and expression of human renal dipeptidase.

Human renal dipeptidase cDNA and genomic DNA were isolated from human kidney cDNA and genomic libraries, respectively. The human renal dipeptidase gene has a total length of approximately 6 kb and consists of ten exons and nine introns. The exons and cDNA each encode the 411 amino acid residues of the precursor protein, including 16 amino acid residues of signal sequence and a hydrophobic carboxyl terminal sequence for the attachment of a phosphatidylinositol glycan. Although the cDNA was slightly different from the cDNA reported by Adachi et al. (1990), the differences observed suggest, by comparison with human genomic DNA, that it may not represent an allelic variant but a cloning artifact. The recombinant human renal dipeptidase was produced on the surface of transfected L929 cells and had the same character as native renal dipeptidase. Northern blotting hybridization analysis showed that renal dipeptidase mRNA is only transcribed in kidney.

Amino Acid Sequence↗
PubMedDate not supplied

Isolation of a novel human gene, MARKL1, homologous to MARK3 and its involvement in hepatocellular carcinogenesis.

Activation of the Wnt-signaling pathway is known to play a crucial role in carcinogenesis of various human organs including the colon, liver, prostate, and endometrium. To investigate the mechanisms underlying hepatocellular carcinogenesis, we attempted to identify genes regulated by beta-catenin/Tcf complex in a human hepatoma cell line, HepG2, in which an activated form of beta-catenin is expressed. By means of cDNA microarray, we isolated a novel human gene, termed MARKL1 (MAP/microtubule affinity-regulating kinase-like 1), whose expression was downregulated in response to decreased Tcf/LEF1 activity. The transcript expressed in liver consisted of 3529 nucleotides that contained an open reading frame of 2256 nucleotides, encoding 752 amino acids homologous to human MARK3 (MAP/microtubule affinity-regulating kinase 3). Expression levels of MARKL1 were markedly elevated in eight of nine HCCs in which nuclear accumulation of beta-catenin were observed, which may suggest that MARKL1 plays some role in hepatocellular carcinogenesis.

Adenoviridae↗
PubMedDate not supplied

An autologous connective tissue tube with high healing ability as a small diameter vascular substitute with temporary antithrombogenicity.

Although autologous connective tissue grafts (ACTG) are an ideal vascular substitute, they have not yet been used as small diameter vascular grafts because of thrombogenicity. We reported on ACTGs in which mesh tubes were fabricated from ultra-fine polyester fibers (UFPF) and used as a framework. Antithrombogenicity was established using an original heparinization method, with a 50% patency 1 month postimplantation. Early failure of these grafts was caused mainly by loss of antithrombogenicity before development of endothelialization on the inner surface. In this study, higher concentrations of heparin were used for in situ heparinization of the grafts before implantation in combination with antiplatelet therapy (cilostazol, OPC-13013 for the first month after substitution for canine carotid arteries. As a result, more complete healing of the grafts was attained, with a patency rate of 63% at 1 month, when small doses of antiplatelet agents were used. More intensive antiplatelet therapy resulted in impairment of graft healing, causing hematomas around the grafts. Thus, optimal doses of antiplatelet agents remain uncertain.

Animals↗
PubMedDate not supplied

Development of ultrafine polyester fiber vascular grafts with high endothelialization capability. Angiogenesis by ultrafine polyester fibers.

The authors previously showed that a vascular prosthesis made of ultrafine polyester fibers (UFPF) had high healing ability even when of low porosity. In this study, new highly porous vascular grafts fabricated from UFPF (water porosity: 3,600 ml/min/cm2, 8 mm in inner diameter and 5 cm in length), were developed and implanted in the thoracic descending aorta of dogs to evaluate their endothelialization capability. Two weeks after implantation, many colonies of endothelial cells with openings of capillary blood vessels were noted, even in the middle portion of the grafts. Numerous fibroblasts and capillary blood vessels were also observed in the synthetic walls. These results suggest that UFPF vascular grafts provide a suitable microenvironment for infiltration and proliferation of fibroblasts, which are accompanied by the capillary formation as nutrient supply; these capillaries provide multiple sources of endothelial coverage on the luminal surface. It is expected that the new, highly porous vascular grafts may have rich endothelialization capability and stable healing properties in humans.

Animals↗
PubMedDate not supplied

A method to reduce thrombogenicity of a graft for small diameter arterial substitution seeded with autologous venous tissue fragments.

The authors successfully applied a method to accelerate endothelialization by tissue fragmentation to a small diameter fabric vascular prosthesis. Tissue fragment seeded grafts showed rapid healing of the neointima. The thrombogenicity of the collagen fibrils in the fragments, however, caused major problems when the method was applied to small diameter grafts: the positively charged collagen fibrils aggregated the negatively charged platelets. The authors masked the fibrils electrostatically with heparin molecules, which are negatively charged. A canine jugular vein was resected, minced into tissue fragments, and suspended in the heparin solution; it then was sieved through the wall of a fabric prosthesis. The grafts (4 mm internal diameter and 3.5 cm in length) were implanted into both carotid arteries of six dogs (12 grafts). Tissue fragment seeded grafts without heparin also were implanted into six dogs. As a control, preclotted fabric grafts were implanted into six dogs (12 grafts). These grafts occluded within 1 week, whereas all the masked grafts were patent without thrombi. In vitro examination of heparin release revealed that approximately 92% of heparin in the graft was released during the first 5 hr, but approximately 6% remained after 25 hr. These results indicate that the method is applicable to small diameter arterial grafts.

Animals↗
PubMedDate not supplied

Rapid neointima formation with elastic laminae similar to the natural arterial wall on an adipose tissue fragmented vascular prosthesis.

A vascular prosthesis that can induce a neointima similar to a natural arterial wall is reported. The authors have developed a sealing method using autologous tissue fragments. The sealed graft showed many advantages, with characteristic neointima formation in an animal study. The grafts were implanted in the thoracic descending aortae of 40 dogs and were removed from 1 hour to 608 days after implantation. Another 40 dogs, used as controls, had a fabric graft implanted using the preclotting method. The luminal surface of the sealed graft was completely endothelialized and the original adipose tissue fragments were absorbed within 1 month. Smooth muscle cells infiltrated and proliferated at the same time as endothelialization took place. Most of the smooth muscle cells were arranged in parallel rows and oriented circumferentially within the graft. At 1 month, elastic fibers appeared around the smooth muscle cells near the anastomotic sites. In the long-term specimens, these elastic fibers constituted a fine lamina in the neointima. Intimal hyperplasia and degenerative changes in the neointima were not observed. These results indicated that the sealing method could induce a very stable neointima with a smooth muscle cell layer and elastic laminae similar to a natural arterial wall within a short period of time throughout the graft wall, with maintenance of the neointima for a long period of time after implantation.

Adipose Tissue↗
PubMedDate not supplied

Development of a vascular prosthesis for a growing child. A graft expandable in vivo.

Specially designed vascular prostheses that can be dilated after implantation using a percutaneous transluminal angioplasty (PTA) balloon catheter have been developed. The grafts are made of woven polyester fiber fabrics, the circumferential yarns of which consist of two different types of polyester fiber bundles: One is a straight weak bundle, the other is a strong bundle wound around the former. The graft with an initial diameter of 6 mm could be dilated to 9 mm by luminal inflation of the balloon four to five times at 10 atmospheres (atm) in vitro. After disrupting the weak bundle by the dilatation procedure, the strong bundles were straightened, which maintained the enlarged diameter of the new caliber. Grafts of 6 mm in initial diameter implanted into the thoracic aortas of mongrel dogs for 3 months also could be dilated in vivo by inflating the PTA four to five times at 15 atm, as found in the vitro study. Macroscopic observation revealed that, around the dilated grafts, only a tiny hematoma was formed and nominal subsequent bleeding was observed, which indicated that the dilatation procedure was performed safely. The graft, which enables adaptation of the hydrodynamic property of the graft to the increased blood flow by PTA after implantation, is applicable in a growing child.

Angioplasty, Balloon↗
PubMedDate not supplied

Impregnation of basic fibroblast growth factor on a microporous small caliber graft enhances vascularization.

The incorporation of a cellular adhesive extracellular matrix and a growth factor into a designed concept for a vital, functioning artificial vascular graft may accelerate tissue regeneration, including endothelialization. Microporous polyurethane grafts (inner diameter, 1.5 mm; wall thickness, 100 microns; length, 20 mm; pore size, 100 microns), fabricated using an excimer laser ablation technique, were coated with a mixed solution of photoreactive gelatin, basic fibroblast growth factor (bFGF), and heparin, and were subsequently photocured by ultraviolet irradiation. Control grafts were treated only with photoreactive gelatin. Both bFGF/heparin impregnated grafts (n = 6) and control grafts (n = 9) were implanted in aortas of rats for 4 weeks. All the implanted grafts were patent when harvested. Endothelialization mainly proceeded from anastomotic sites for both groups. The endothelial coverage in the bFGF/heparin impregnated groups was greater than that in the control animals. At the midportion of the grafts, regenerated endothelial and subendothelial layers were seen for the bFGF/heparin groups, but only fibrin layers were seen for the controls. Thus, coimmobilization of bFGF and heparin significantly enhanced neoarterial wall regeneration through perianastomotic as well as transmural tissue ingrowth. The former was more extensive than the latter.

Animals↗
PubMedDate not supplied

A collagen coated fabric vascular prosthesis as a punctureable A-V shunt.

A fabric vascular prosthesis sealed with succinylated collagen (SC) was developed as an arteriovenous (A-V) shunt graft for hemodialysis. The SC graft was soft, pliable, flexible, and puncturable, with quick hemostasis. A needle puncture made a smaller hole in the SC graft wall than in a control expanded-polytetrafluoroethylene (e-PTFE) graft such as is usually used for an A-V shunt. The SC graft was extremely hydrous, because it is sealed with water, which is absorbed into the intermolecular spaces of negatively charged collagen. The SC suspension was injected with pressure into a knitted fabric vascular prosthesis wall (water permeability, 1,200 ml) so as to become entangled in the Dacron network. The graft then was lyophilized and thermally cross-linked. Water leakage from six holes created by an 18 G needle puncture in vitro under water pressure of 120 mmHg was 34.5 +/- 29.9 ml/min in the SC graft and 169.9 +/- 38.5 ml/min in the control e-PTFE graft. Hemostatic time at six 18G needle puncture sites on grafts implanted in the abdomen of 12 dogs was 4.5 +/- 2.5 mins in the SC graft and 34.2 +/- 11.5 mins in the control graft. After implantation, the luminal surface of the SC grafts had a thinner thrombus layer than did the control grafts. After 1 week, a thin thrombus layer covered the luminal surface of the SC grafts, and puncture sites were recognized as small dots under it, but in the control grafts, the thrombus layer was thick and the puncture sites could not be seen. These results suggest that the SC graft is less thrombogenic and has less blood leakage from the puncture sites than does the control graft.

Animals↗
PubMedDate not supplied

In vitro evaluation of metabolic functions of a bioartificial liver.

The purpose of this study is to develop a bioartificial liver (BAL) with such a simple structure that it can be prepared within several hours and through which whole blood can be perfused as in current hemodialyzers. Hepatocytes were isolated from 37 pigs; each liver weighed 300 to 400 g. The average yield of hepatocytes was 2.4 +/- 0.6 x 10(10) cells per liver, with a cell viability of 89.6 +/- 3.9%. To prepare a BAL device, a cartridge, composed of hollow fibers made of cellulose diacetate was used. Nominal cut-off molecular weight of the hollow fibers was 68 kDa, and the internal diameter was 195 microm. One hundred milliliters of hepatocyte suspension, containing 1 x 10(10) cells, was inoculated into the inner space of the hollow fibers, and both the inlet and outlet of the hollow fiber cartridge were closed. It took only 3 hrs from administration of the pig's anesthesia to the start of an in vitro evaluation of the prepared BAL device. To evaluate the functions of this BAL quantitatively, using a pharmacokinetic method, a mixture of fresh human blood and Dulbecco's modified Eagle medium was circulated in the shell space of the hollow fibers at 200 ml/min. Chemicals (lidocaine, ammonia, and galactose) were then loaded into the perfusion medium. The average intrinsic clearance of the BAL device was found to be 46 ml/min for lidocaine and 8.8 ml/min for ammonia. The galactose elimination capacity of the BAL device was 1.34 mg/min. The metabolic function of the BAL device decreased by 81%, 49%, and 64% of the initial function for lidocaine, ammonia, and galactose, respectively, after 10 days of in vitro circulation.

Animals↗
PubMedDate not supplied

Morphologic studies of hepatocytes entrapped in hollow fibers of a bioartificial liver.

A bioartificial liver cartridge was prepared by inoculating porcine hepatocytes into the inner space of hollow fibers of a hemodialyzer. The hepatocytes formed rod shaped cell aggregates during in vitro perfusion culture within 1 day. Morphologic examination was carried out on the aggregates by optical and electron microscopy. Each hepatocyte was in direct contact with adjacent cells and a bile canaliculus-like structure was occasionally seen between hepatocytes. High magnification observation showed that the canaliculus was separated from the remainder of the intercellular space by a tight junction. These facts suggest that the hepatocytes formed functionally associated cell aggregates with a compact morphology not unlike hepatocyte spheroids. These structures were well maintained for 7 days in culture, and then the amorphous area in the aggregates and the nonviable cell number increased with lengthening culture period. The bioartificial liver maintained the ability to metabolize lidocaine, ammonia, and galactose for 7 days and then deteriorated with time.

Ammonia↗
PubMedDate not supplied

Computed tomography of hydrosalpinx following tubal ligation.

The CT findings in three cases of surgically proven hydrosalpinx following tubal ligation are described. In every case a cystic mass of characteristic tubular shape was detected in the pelvic adnexal region. These findings can be considered diagnostic of iatrogenic hydrosalpinx.

Adult↗