Biomedical subjects

Y Takeuchi

Publications and source records attributed to Y Takeuchi.

At least 415 records · Page 23Linked to original sources

PubMed1996

Molecular cloning of human mitochondrial glycerophosphate dehydrogenase gene: genomic structure, chromosomal localization, and existence of a pseudogene.

cDNA of mitochondrial glycerophosphate dehydrogenase (mGPDH), a defect of which is a possible cause of non-insulin dependent diabetes mellitus, was cloned from a human insulinoma cDNA library. The deduced amino acid sequence showed 91% and 92% homology with those of rat and mouse mGPDH, respectively. The mGPDH gene was mapped to chromosome 2q23 by FISH analysis. Genomic clones for mGPDH were then isolated using mouse mGPDH cDNA and PCR products of human mGPDH cDNA as probes. Genomic structure was studied by sequencing the exon-intron boundaries and by PCR amplification of intronic regions using genomic clones as templates. The human mGPDH gene was shown to be composed of 15 coding exons, containing a (CA)n repeat region inside the gene, which was not polymorphic in the Japanese population. Genomic cloning also identified a pseudogene located on chromosome 19q13.4. These results provide information useful for analyzing the mGPDH gene in patients with non-insulin dependent diabetes mellitus.

Amino Acid Sequence↗

PubMed1996

Localization of sympathetic and parasympathetic neurons innervating pancreas and spleen in the cat.

The localization of sympathetic and parasympathetic neurons innervating the pancreas and spleen was studied in the cat utilizing retrograde transport of wheat germ agglutinin conjugated horseradish peroxidase (WGA-HRP). Injection of WGA-HRP into the pancreas resulted in retrograde labeling in the whole of the solar plexus, while injection of WGA-HRP into the spleen also resulted in heavy labeling in the celiac ganglia bilaterally. Only a few labeled neurons were distributed in the superior mesenteric ganglion. With respect to parasympathetic innervation, HRP-labeled pancreatic and splenic neurons were found throughout the rostrocaudal extent of the dorsal motor nucleus of the vagus nerve (DMV) bilaterally. Although pancreatic neurons in the DMV were mainly observed in limits rostral to the obex, splenic neurons were centered at the level of the obex.

Animals↗

PubMed1996

Comparison of efficiency of infection of human gene therapy target cells via four different retroviral receptors.

The relative efficiency of transduction of gene therapy target cells was measured for retroviruses bearing the envelopes of amphotropic murine leukemia virus (MLV-A), xenotropic murine leukemia virus (MLV-X), gibbon ape leukemia virus (GALV), feline leukemia virus subgroup B (FeLV-B), and the feline endogenous virus RD114. These viruses use various cell-surface receptors. Activated peripheral blood lymphocytes (PBL) and primary melanoma cultures were infected relatively poorly by MLV-X pseudotypes. RD114 pseudotypes infected PBL relatively well, whereas bone marrow progenitor cells were efficiently infected by all viruses. Helper-free virus bearing the envelopes of MLV-A, RD114, or GALV was similarly tested. All infected melanoma or bone marrow progenitor cells efficiently, whereas MLV-A was relatively inefficient for infection of PBL. The general utility of RD114 pseudotyped virus for gene delivery coupled with its resistance to inactivation by human serum makes this envelope the most suitable choice for in vivo gene therapy.

Base Sequence↗

PubMed1996

Effect of metoclopramide on muscle sympathetic nerve activity in humans.

The aim of this study was to determine the effect of metoclopramide on the sympathetic nervous system. Muscle sympathetic nerve activity was increased in two stages after metoclopramide injection. The initial increase in sympathetic nerve activity may result from the unloading of arterial baroreceptors because there was a negative correlation between mean blood pressure and muscle sympathetic nerve activity. The later increase in muscle sympathetic nerve activity may be attributed to the central activation of the sympathetic nervous system because there was a positive correlation between mean blood pressure and muscle sympathetic nerve activity. These results suggest that metoclopramide activates the sympathetic nervous system by two different mechanisms.

Adrenergic Fibers↗

PubMed1996

Toxic effects of hexane derivatives on cultured rat Schwann cells.

The cytotoxic effects of the following five hexane-related compounds were examined on Schwann cell DNA synthesis: 2,5-hexanedione (2,5-HD), 2-hexanol (2-OH), 2-hexanone (MnBK), 2,5-dimethylfuran (DF) and gamma-valerolactone (VL). Schwann cells were isolated from the sciatic nerves of neonatal Sprague-Dawley rats and cultured. [(3)H]-thymidine incorporation into Schwann cell nuclei was measured by scintillation spectrometry and autoradiography when hexane derivatives were added to the culture medium. All of the hexane-related compounds suppressed [(3)H]-thymidine incorporation in a concentration-dependent manner. DF was the most cytotoxic for the inhibition of Schwann cell DNA synthesis among the compounds. The finding suggests that DF-mediated cytotoxicity should be taken into account as a possible additional mechanism of hexane intoxication, especially in the impairment of mitotic cells.

Animals↗

PubMed1996

A critical role of VLA-4 in erythropoiesis in vivo.

Hematopoiesis requires specific interactions with the microenvironments, and VLA-4 has been implicated in these interactions based on in vitro studies. To study the role of VLA-4 in hematopoiesis in vivo, we performed in utero treatment of mice with an anti-VLA-4 monoclonal antibody. Although all hematopoietic cells in fetal liver expressed VLA-4, the treatment specifically induced anemia. It had no effect on the development of nonerythroid lineage cells, including lymphoids and myeloids. In the treated liver almost no erythroblast was detected, whereas the erythroid progenitors, which give rise to erythroid colonies in vitro, were present. These results indicate that VLA-4 plays a critical role in erythropoiesis, while it is not critical in lymphopoiesis in vivo.

Animals↗

PubMed1996

Differentiation and cell surface expression of transforming growth factor-beta receptors are regulated by interaction with matrix collagen in murine osteoblastic cells.

Although transforming growth factor (TGF)-beta enhances bone formation, it inhibits the differentiation of osteoblasts. To clarify the regulatory mechanism of osteoblastic differentiation and TGF-beta actions, the relationship among differentiation, TGF-beta actions, and matrix protein synthesis was examined using murine osteoblast-like MC3T3-E1 cells. Alkaline phosphatase (ALP) activity continued to increase during long-term cultures, and the increase was closely associated with a reduction in cell surface TGF-beta receptors competent to bind TGF-beta. Both the stimulation of proteoglycan synthesis and the inhibition of ALP activity by TGF-beta were also suppressed. Collagen synthesis inhibitors and an anti-alpha2beta1 integrin blocking antibody blocked the changes in ALP activity and TGF-beta receptors, and a DGEA peptide that interferes binding of collagen to alpha2beta1 integrin also blocked the increase in ALP activity. Furthermore, when MC3T3-E1 cells were cultured on extracellular matrix layers obtained from these cells, all the differentiation-associated changes could be observed without collagen production, and the extracellular matrix-induced differentiation was also blocked by an anti-alpha2beta1 integrin antibody. These results demonstrate that the interaction of cell surface alpha2beta1 integrin with matrix collagen synthesized by osteoblasts themselves is involved in the osteoblastic differentiation and the reduction in cell surface receptors and actions of TGF-beta. It is suggested that matrix collagen synthesized under the stimulation by TGF-beta plays an important role in the regulation of osteoblastic differentiation and TGF-beta actions by differentiation-associated down-regulation of TGF-beta receptors.

3T3 Cells↗

PubMed1996

Sensitization of cells and retroviruses to human serum by (alpha 1-3) galactosyltransferase.

Mammalian C-type retroviruses are inactivated by human serum, following triggering of the classical complement cascade. This may have inhibited transmission to humans of C-type oncoviruses from other mammals. Indeed, the retroviruses human immunodeficiency virus and human T-cell leukaemia virus are resistant to human complement. Antibody-independent activation of human C1q, the first component of the classical pathway, by retroviral envelope proteins has been described. However, retroviruses produced from human cells are resistant to inactivation by human complement and human serum is known to contain antibodies directed against carbohydrates on retroviral envelopes. Gal(alpha 1-3)Gal terminal carbohydrates are expressed by most mammals but are absent in humans, which lack a functional (alpha 1-3)galactosyltransferase gene. Here, we demonstrate that anti-Gal(alpha 1-3)Gal antibodies in human serum inactivate retroviruses produced from animal cells. Expression of porcine (alpha 1-3)galactosyltransferase in human cells renders the cells and the retroviruses they produce sensitive to human serum.

3T3 Cells↗

PubMed1996

Morphological study of the human maxillofacial venous vasculature: examination of venous valves using the corrosion resin cast technique.

BACKGROUND: The venous drainage in the human head and neck, structures located superior to the heart, generally does not counter the force of gravity. Accordingly, venous valves in the human head have been reported to be few or nonexistent, and therefore the direction of venous drainage is variable and obscure. METHODS: We investigated whether venous valves were present in 13 heads of human adult cadavers using scanning electron microscopic observation of corrosive resin casts in the human maxillofacial region. This technique afforded the observation of the venous valves. RESULTS: Venous valves were found throughout the facial region. In particular, there were many valves distributed in the lingual, upper and lower labial, facial and pharyngeal veins. The venous valves were particularly well formed at motile parts of the maxillofacial region. CONCLUSIONS: It is suggested that these valves may aid the venous blood return and permit the blood drainage in one direction.

Aged↗

PubMed1996

cDNA cloning and expression of a gene for 3-ketoacyl-CoA thiolase in pumpkin cotyledons.

A cDNA clone for 3-ketoacyl-CoA thiolase (EC 2.3.1.16) was isolated from a lambda gt11 cDNA library constructed from the poly(A)+ RNA of etiolated pumpkin cotyledons. The cDNA insert contained 1682 nucleotides and encoded 461 amino acid residues. A study of the expression in vitro of the cDNA and analysis of the amino-terminal sequence of the protein indicated that pumpkin thiolase is synthesized as a precursor which has a cleavable amino-terminal presequence of 33 amino acids. The amino-terminal presequence was highly homologous to typical amino-terminal signals that target proteins to microbodies. Immunoblot analysis showed that the amount of thiolase increased markedly during germination but decreased dramatically during the light-inducible transition of microbodies from glyoxysomes to leaf peroxisomes. By contrast, the amount of mRNA increased temporarily during the early stage of germination. In senescing cotyledons, the levels of the thiolase mRNA and protein increased again with the reverse transition of microbodies from leaf peroxisomes to glyoxysomes, but the pattern of accumulation of the protein was slightly different from that of malate synthase. These results indicate that expression of the thiolase is regulated in a similar manner to that of other glyoxysomal enzymes, such as malate synthase and citrate synthase, during seed germination and post-germination growth. By contrast, during senescence, expression of the thiolase is regulated in a different manner from that of other glyoxysomal enzymes.

Acetyl-CoA C-Acyltransferase↗

PubMed1996

Intraabdominal contamination after gallbladder perforation during laparoscopic cholecystectomy and its complications.

BACKGROUND: Gallbladder perforation often occurs during laparoscopic cholecystectomy. METHODS: The frequency and causes of gallbladder perforation as well as the relevant clinical background factors were investigated in 110 patients undergoing laparoscopic cholecystectomy. We also evaluated intraperitoneal contamination by bacteria and gallstones at the time of gallbladder perforation and investigated whether perforation caused early or late postoperative complications. RESULTS: Intraoperative gallbladder perforation occurred in 29 of the 110 patients (26.3%). It was caused by injury with an electric knife during dissection of the gallbladder bed, injury during gallbladder retraction with grasping forceps, injury during gallbladder extraction from the abdomen, and slippage of cystic duct clips (potentially causing bile and stone spillage). Perforation was more frequent in patients with positive bile cultures and in those with pigment stones (p < 0.02), but not in patients with cholecystitis or cystic duct obstruction. The peritoneal cavity was contaminated by bacteria in 11/29 patients (37.9%) and by spilled stones in 3/29 patients (10.3%). There was no difference in the incidence of postoperative complications between the patients with and without perforation either in the early postoperative period or during follow-up for 24-42 months. Only one patient developed abdominal pain and fever in the early postoperative period, and they were probably related to perforation. CONCLUSIONS: Although gallbladder perforation is sometimes unavoidable during laparoscopic cholecystectomy, the risk of severe complications appears to be minimized by early closure of perforation, retrieval of as many of the spilled stones as possible, and intraperitoneal lavage.

Cholecystectomy, Laparoscopic↗

PubMed1996

Surgical treatment for right ventricular perforation caused by transvenous pacing electrodes: a report of three cases.

We experienced three cases of right ventricular perforation that were induced by transvenous pacing electrodes. The patients were a 72-year-old man who underwent percutaneous transluminal coronary recanalization and angioplasty, an 80-year-old woman who had temporary transvenous pacing for a complete atrioventricular block induced by acute valvular heart failure, and a 44-year-old man who had received a permanent pacemaker. All three patients were treated surgically. The first and second patients demonstrated either cardiac tamponade or hemopericardium necessitating pericardial drainage. Spontaneous hemostasis did not occur in cases 1 and 2, due to either anticoagulant therapy or myocardial degeneration. Such patients require surgical closure of the perforation and pericardial drainage as soon as pericardial effusion is confirmed. In contrast, middle-aged individuals without myocardial damage, such as patient 3, need only a simple removal and repositioning of the electrode followed by serial echocardiography.

Adult↗

PubMed1996

Adhesive protein cDNA sequence of the mussel Mytilus coruscus and its evolutionary implications.

cDNA encoding the adhesive protein of the mussel Mytilus coruscus (Mcfp1) was isolated. The coding region encoded 848 amino acids (a.a.) comprising the 20-a.a. signal peptide, the 21-a.a. nonrepetitive linker, and the 805-a.a. repetitive domain. Although the first 204 nucleotides and the 3'-untranslated region of Mcfp1 cDNA were homologous to corresponding parts of M. galloprovincialis adhesive protein (Mgfp1) cDNA, the other parts diverged. The representative repeat motif of the repetitive domain, YKPK(I/P)(S/T)YPP(T/S), was similar but slightly different from the repeat motif of Mgfp1. The codon usage patterns for the same amino acids were different in different positions of the decapeptide motif. Almost identical nucleotide sequences encoding the two to 13 repeats appeared several times in the repetitive region, which suggests that the adhesive protein genes of mussels have evolved through the duplication of these repeat units.

Amino Acid Sequence↗

PubMed1996

Elevated circulating levels of tumor necrosis factor in patients with mitral valve disease and ventricular septum defect.

Elevated levels of circulating tumor necrosis factor (TNF)-alpha have been reported in patients with decreased left ventricular ejection fraction. Also, TNF has been reported to depress myocardial contractility. In our previous study, no correlation was found between the plasma level of TNF and clinical parameters in patients with cardiomyopathy. In the present study, we detected elevated levels of circulating TNF-alpha in 5 out of 15 patients with mitral valve disease and in 1 patient with ventricular septal defect whose left ventricular ejection fraction was within the normal range. The levels of TNF-alpha were not correlated with any hemodynamic parameters. Further studies are necessary to clarify the mechanisms of the regulation and effects of TNF-alpha in patients with chronic heart failure.

Adult↗

PubMed1996

A mathematical model for drug administration by using the phagocytosis of red blood cells.

A mathematical model for the delivery of drug directly to the macrophages by using the phagocytosis of senescent red blood cells is proposed. The model is based on the following assumption: At time t = 0 a preassigned red blood cell population n(0,a) = phi (a), a > 0, loaded by the drug, is injected in the blood circulation. Among the cells of that population only those with an age a > or = a (a = 120 days) will be phagocytosed by macrophages. Of course, the lifetime of the drug must be higher than a. Within the red blood cells it cannot be metabolized, neither can it diffuse through their membranes. The emphasis of the paper is on the mathematical properties and on the formulation of the control problem.

Drug Therapy↗

PubMed1996

Efficacy of short-term treatment of pertussis with clarithromycin and azithromycin.

The recommended treatment for pertussis is erythromycin, 40 to 50 mg/kg per day for 2 weeks. The newly developed macrolides, clarithromycin and azithromycin, have been demonstrated to be superior to erythromycin because of improved absorption and a longer half-life. As a result, we conducted two separate comparison studies to evaluate the efficacies of clarithromycin, 10 mg/kg per day, twice a day for 7 days, and azithromycin, 10 mg/kg per day, once a day for 5 days, compared with the standard erythromycin regimen. A total of 17 patients, including 10 infants 1 year of age or less, for whom pertussis had been confirmed by culture, were allocated to receive either clarithromycin or azithromycin treatment, and each patient was matched (age, sex, and immunization status) with historical control subjects who had been treated with erythromycin. Eradication rates examined at 1 week after treatment were as follows: 9 of 9 with clarithromycin versus 16 of 18 with erythromycin (psi M-H = 1.13), and 8 of 8 with azithromycin versus 13 of 16 with erythromycin (psi M-H = 1.23). No bacterial relapse after treatment was detected in either group. All isolated strains of Bordetella pertussis were susceptible to clarithromycin, azithromycin, and erythromycin, and no change in drug susceptibility has been confirmed for the past 20 years in Japan. Because of the very low incidence of pertussis resulting from widespread use of acellular pertussis vaccination, this study did not enroll a large number of patients; however we conclude that short-term treatment with clarithromycin or azithromycin is expected to be equal or superior to the standard long-term erythromycin regimen for pertussis.

Adolescent↗

PubMed1996

Distribution and morphology of valves in the human external jugular vein: indications for utilization in microvascular anastomosis.

PURPOSE: This study examined the valves in the external jugular vein (EJV) that could affect microvascular anastomosis and increase the risk of thrombogenesis. MATERIALS AND METHODS: The EJVs of 57 sides from 36 cadavers aged 40 to 95 years (20 males and 16 females) were dissected. After opening the veins, the distribution and morphology of the valves were investigated using a stereoscopic microscope. The length of the valves and inner diameter of the vessels were measured and related to the location of the valves. RESULTS: Forty-nine (86%) of 57 EJVs were confluent with the subclavian vein. The EJV possessed bicuspid valves, and in 46 (93.9%) of the 49 specimens there were valves at the junction with the subclavian vein, whereas 44 (89.8%) contained valves in the middle portion of the specimen. The length of the valves was less than twice the inner diameter, and some were occasionally only rudimentary. CONCLUSION: Numerous valves exist in the middle portion of the EJV where microvascular anastomoses are performed. When valves are observed in the site of anastomosis, they can be avoided by resecting a length equal to approximately twice the inner diameter.

Adult↗

PubMed1996

Effects of asymmetric dynamic and isometric liftings on strength/force and rating of perceived exertion.

A laboratory study was undertaken to determine the postural and physical characteristics and subjective stress during dynamic lifting of a usual load (10 kg) compared with during isometric lifting. The authors also aimed to clarify the effects of asymmetric lifting on these parameters. The subjects were thirteen male college students. They were asked to lift a box weighing 10 kg. They performed sixteen different lifting tasks from the floor to a height of 71 cm, involving a combination of three independent factors: two lifting modes (isometric lifting and dynamic lifting), four lifting angles in relation to the sagittal plane (sagittal plane, right 45 degree, right 90 degree and left 90 degree planes) and two lifting postures (squat and stoop). For each lifting task, strengths or forces and ground reaction forces were measured. At the end of each task, the authors asked the subjects to rate their perceived exertion (RPE) during lifting at ten sites of the body. Angle factor had a significant effect on isometric strengths and dynamic peak forces. Isometric strengths during the maximum 3 s were highest in lifting in the right 45 degree plane, followed by that in the sagittal plane, while those in the right 90 degree and left 90 degree planes were the lowest. However, peak forces in dynamic lifting were the highest in the lifting in the sagittal plane, followed by that in the right 45 degree plane, while those in the right 90 degree and left 90 degree planes were the lowest. Postural factor had a significant effect on height at peak force, which is higher in squat lifting than in stoop lifting. RPEs for the left arm, the backs and the right whole body in isometric lifting were significantly higher than in dynamic lifting of 10 kg. There were remarkably high RPEs for the ipsilateral thigh to the box in right 90 degree and left 90 degree planes during both isometric and dynamic liftings. Locations of the resultant force consisting of three component forces on the force plate were closer to the foot on the same side as the box in asymmetric lifting. Thus, some similarities and differences were found between isometric lifting and dynamic liftings regarding the indexes of strength used in this experiment. The authors consider that the subjects used the foot nearer to the box as a fulcrum during asymmetric lifting. Dynamic measurement using the 10 kg weight is less stressful than the conventional isometric measurement. It was possible to obtain the height data at peak force and time-based changes in the force and the box location during lifting only through dynamic lifting measurement. The results provide new knowledge about the biomechanical features of dynamic lifting tasks.

Adolescent↗