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Biomedical subjects

E Kobayashi

Publications and source records attributed to E Kobayashi.

At least 163 records · Page 9Linked to original sources

Enzymatic and genetic bases on assimilation, depolymerization, and transport of heteropolysaccharides in bacteria.

When microorganisms utilize macromolecules for their growth, they commonly produce extracellular depolymerization enzymes and then incorporate the depolymerized low-molecular-weight products. Assimilation of heteropolysaccharides (gellan and xanthan) by Bacillus sp. GL1 depends on this generally accepted mechanism. On the other hand, Sphingomonas sp. A1 represents an unexplored specific and interesting system for macromolecule assimilation. In the presence of heteropolysaccharide (alginate), the bacterium forms a mouthlike pit on its cell surface and directly incorporates the macromolecule using a novel ATP-binding cassette transporter (ABC transporter). In this review, we discuss enzymatic and genetic bases on the depolymerization and assimilation routes of heteropolysaccharides in bacteria, with particular emphasis on the novel incorporation system for macromolecules, characteristic post-translational modification processes of polysaccharide lyases and on the mouthlike pit structure on the bacterial cell surface.

Journal Article↗

A linkage map of 243 DNA markers in an intercross of Göttingen miniature and Meishan pigs.

A resource family of pigs has been constructed by using a boar of Göttingen miniature pig and two sows of Meishan pig as parents. In the construction of the family, two F1 males and 18 F1 females were intercrossed to generate 143 F2 offspring. The members of the family were genotyped using 243 genetic markers including 26 markers developed in our laboratory in order to generate a linkage map of markers for use in detecting quantitative trait loci (QTLs) in the family. The markers consisted of 237 microsatellites, five PRE-1 markers, and one RFLP marker. The linkage map was revealed to cover all 18 autosomes and the X chromosome; and the total length of the sex-averaged linkage map was calculated to be 2561.9 CM. Four out of the 26 markers developed in our laboratory exended the current linkage map at the termini of chromosomes 1p, 5p, 11p, and Xq. The linkage maps of all the chromosomes except for chromosome 1 were found to be longer in females than in males. Concerning chromosome 1, the length of the linkage map showed no difference between females and males, which was attributed to low recombination rates between markers localized in the centromeric region in females. The average ratio of female-to-male recombination was calculated to be 1.55.

Animals↗

Associations of the angiotensinogen gene (M235T, T174M) and the angiotensin I-converting enzyme gene (I/D) with blood pressure in Japanese workers.

Blood pressure may be influenced by several polymorphisms associated with hypertension, such as the angiotensinogen gene (M235T, T174M) and the angiotensin I-converting enzyme gene (I/D). We investigated the associations of these polymorphisms with blood pressure and components of the renin-angiotensin system in Japanese workers. Additionally, we examined whether the polymorphisms were independently associated with blood pressure when other factors were taken into consideration in a general linear model. The study population, which was entirely Japanese, consisted of 196 male subjects. Subjects were selected from workers who received a company health examination. Systolic blood pressure of the M235T MM genotype was significantly higher than that of the MT genotype. Diastolic blood pressure of the M235T MM genotype was significantly higher than that of the MT or TT genotypes. Serum ACE activity of the ACE II genotype was significantly lower than that of the ID or DD genotypes. Multivariate analysis using a general linear model, including age and body mass index, demonstrated that the M235T MM genotype was one of the independent factors affecting blood pressure. The present study demonstrated that the M235T MM genotype was independently associated with systolic blood pressure and diastolic blood pressure in Japanese male workers.

Adult↗

Effects of intestinal bacteria on the development of colonic neoplasm II. Changes in the immunological environment.

To study the effects of intestinal bacteria on the development of colonic neoplasm, we have established gnotobiotic mice with a single species of intestinal bacteria. In the previous study, the incidence of colonic adenoma induced with 1,2-dimethylhydrazine (DMH) in the gnotobiotic mice with Lactobacillus acidophilus, gnotobiotic mice with Escherichia coli and germ-free mice were 30, 50 and 74%, respectively. In this study, 7-week-old mice in each group were sacrificed without the administration of DMH to examine the constituents of immuno-competent cells in various mouse organs using flow cytometry. In the gnotobiotic mice, CD3 intermediate interleukin (IL)-2Rbeta positive cells were observed predominantly in the liver. In the gnotobiotic mice with L. acidophilus, Mac-1 positive Gr-1 positive cells were observed predominantly in the colonic lamina propria. The activation of extrathymic T cells in the liver and granulocytes in the colonic mucosa may be related to anti-neoplastic effects of L. acidophilus in this experimental model.

1,2-Dimethylhydrazine↗

A novel assay for serum complement activity: C42 generation assay.

BACKGROUND: In most clinics, laboratory tests for serum complement are limited to immunochemical determinations of C3 and C4 and are occasionally extended to the hemolytic titration of total complement functional activity (CH50). However, these tests are often not sufficient for the analysis of low CH50 serum. METHODS: A novel assay for serum complement activity, the C42 generation assay, has been developed. The principle of this assay is based on the hemolysis of sensitized sheep erythrocytes (EA) by complement components in two sera: C42 (the classical pathway C3 convertase) is generated on EA by C1, C4 and C2 in the first serum, followed by a second reaction leading to hemolysis by C3-C9 supplied by the addition of the second serum in the presence of EDTA. RESULTS: This methodology permits the evaluation of two distinct serum complement activities of a test serum. The combined activity of C1, C4 and C2, as well as the combined activity of C3-C9, can be estimated from the observed degrees of hemolysis. Information obtained from this assay is helpful for the analysis of test serum determined to have decreased CH50. Several clinical cases are presented in which this assay was utilized. CONCLUSIONS: The C42 generation assay is another functional assay of serum complement which can provide information beyond that obtained from the typical serum CH50 assay. Since intermediate cells or isolated complement components are not necessary, this assay can be employed rapidly and economically in a clinical setting.

Animals↗

Comparison of cyclosporin A and tacrolimus concentrations in whole blood between jejunal and ileal transplanted rats.

Most immunosuppresive drugs are absorbed from the intestine after oral administration, although there is some difference of bioavailability between ileum and jejunum. Using an orthotopic segmental small bowel transplantation (SBT) model in rats, we studied the pharmacokinetic profiles of cyclosporin A and tacrolimus concentrations after oral intake, comparing jejunal and ileal transplanted rats. Two types of segmental SBT (jejunal and ileal SBT) in a syngeneic combination were performed. After oral administration of cyclosporin A (10mgkg(-1) or tacrolimus (5 mg kg(-1)), pharmacokinetic data were obtained from the long-surviving rats transplanted with segmental SBT. To determine the effect of additional bile on cyclosporin absorption, an emulsion of cyclosporin A with fresh bile juice was re-challenged on segmental SBT rats before killing. A histological study was also performed by use of the intestinal grafts from the killed SBT rats. A higher concentration of cyclosporin A was observed in the ileum-grafted rats than in the rats which received the jejunal grafts. Oral bioavailability of cyclosporin A in ileal SBT rats tended to be increased by addition of fresh bile juice, but that in jejunal SBT rats did not change. On the other hand, there was no significant difference of tacrolimus concentration between jejunum- and ileum-transplanted rats. Histological studies showed that the superficial mucosal layer of both grafts, but especially the ileal graft, was markedly elongated compared with that of normal intestine. The present study showed that cyclosporin A was more actively absorbed from ileum than from jejunum in SBT, but tacrolimus was absorbed equally from both sites. These data suggest that cyclosporin A concentration is satisfactorily controlled in the segmental ileal graft, while there is no difference of tacrolimus absorption between ileal and jejunal graft.

Administration, Oral↗

Effect of pretreatment with FTY720 and cyclosporin on ischaemia-reperfusion injury of the liver in rats.

The effect of pretreatment with FTY720 (2-amino-2-[2-(4-octylphenyl)ethyl]-1,3-propanediol hydrochloride) or cyclosporin, or both, on neutrophil-mediated injury has been examined by use of a rat model of transient clamping of hepatic flow. Pretreatment with FTY720 alone or with cyclosporin induced a marked reduction of circulatory lymphocytes, whereas the use of these drugs in combination was very effective at suppressing the elevation of the number of peripheral polymorphonuclear neutrophils (PMN) after reperfusion. Pretreatment with cyclosporin, with or without FTY720, significantly reduced hepatic damage, whereas FTY720 alone tended to prolong hepatic damage. Pretreatment of cyclosporin alone, but not in combination with FTY720, significantly reduced the accumulation of PMN and led to lower myeloperoxidase levels in the damaged liver. In conclusion, pretreatment with cyclosporin, with or without FTY720, reduced hepatic damage after warm ischaemia-reperfusion, whereas pretreatment with FTY720 alone tended to prolong this damage.

Animals↗

Pharmacokinetic drug interactions between ampiroxicam and sulfaphenazole in rats.

The aim of the present study was to determine the effect of sulfaphenazole (SP) on the pharmacokinetics of ampiroxicam (AM) which is metabolized by cytochrome P-450 (CYP) 2C9, since SP is a potent inhibitor of CYP 2C9, and so a dramatic pharmacokinetic drug interaction between both drugs is assumed after dosing. Single intravenous and oral administrations of AM (5 and 7.5 mg/kg piroxicam equivalent, respectively) and SP (80 and 120 mg/kg, respectively) to rats did not significantly alter the elimination kinetics of AM and piroxicam (PX) converted from AM. When SP was preloaded orally at 2 h before the dosing of AM, and when AM and SP were orally coadministered for 7 d, the elimination of PX from plasma was slightly retarded and the area under the plasma concentration-time curve (AUC) was increased 77 and 53%, respectively, but not significantly, compared with those after AM alone. On the other hand, a significantly decreased metabolic conversion of PX to 5'-hydroxyPX in plasma was observed by these treatments (p<0.05). In order to clarify the mechanism for the interaction, hepatic and intestinal metabolizing enzyme activities, CYP, uridine 5'-diphosphoglucuronyltransferase (UDPGT) and aryl esterase, were assayed after single and multiple oral administrations of AM or AM and SP. The enzyme activities were hardly inhibited by the treatment, indicating that the inhibition of CYP and hydrolytic enzymes by SP was approximately denied. These results suggest that SP does not significantly affect the pharmacokinetics of AM and PX in rats. However, the pharmacokinetic drug interaction between both drugs in man may not always be ignored.

Administration, Oral↗

Synthesis and antitumor activity of duocarmycin derivatives: a-ring pyrrole compounds bearing 5-membered heteroarylacryloyl groups.

A series of A-ring pyrrole compounds of duocarmycin bearing 5-membered heteroarylacryloyl groups (thienylacryloyl and pyrrolylacryloyl) and heteroarylcarbonyl groups were synthesized and evaluated for in vitro anticellular activity against HeLa S3 cells and in vivo antitumor activity against murine sarcoma 180 in mice. Most of the thienylacrylates displayed in vitro anticellular activity equivalent to 4'-methoxycinnamates. Among the 8-O-[(N-methylpiperazinyl)carbonyl] derivatives of methoxy-thienylacrylates, compound 11b, having 4'-methoxy-2'-thienylacryloyl as segment-B (Seg-B), showed remarkably potent antitumor activity and low peripheral blood toxicity in vivo, which were equal to those of 8-O-[(N-methylpiperazinyl)carbonyl] derivatives of 4'-methoxycinnamates, compared with the A-ring pyrrole derivatives having the trimethoxyindole skeleton in Seg-B. On the other hand, the 2'-pyrrolylacrylates having a double bond as spacer showed 10(2)- to 10(3)-fold stronger anticellular activity than 2'-pyrrolecarboxylates (IC50 < 0.3 nM, 72 h-exposure). The 8-O-acetate and 8-O-[(N-methylpiperazinyl)carbonyl] derivatives of 2'-pyrrolylacrylates exhibited an antitumor effect at a lower dose compared with the 8-O-[(N-methylpiperazinyl] derivatives of 4'-methoxycinnamate (1j). Moreover, it was expected that the antitumor activity would be increased by the strength of the extra hydrogen bond formed between the nitrogen of the pyrrole amido group and DNA, owing to the increase of the number of N-methyl-2'-pyrrolecarboxamide units. However, 2'-pyrrolylacrylates having three N-methyl-2'-pyrrolecarboxamide units showed nearly equal antitumor activity to 2'-pyrrolylacrylates having only one N-methyl-2'-pyrrolecarboxamide unit.

Acrylates↗

Levothyroxine-induced liver dysfunction in a primary hypothyroid patient.

Here we report a case of levothyroxine-induced liver dysfunction. T4 (levothyroxine) has been more commonly used for the treatment of hypothyroidism than T3 active hormone (triiodothyronine), because with the former drug a stabler plasma concentration is obtained after oral administration. Although there are few reports on levothyroxine-induced liver dysfunction, we treated a primary hypothyroid patient with high serum aminotransferase after administration of levothyroxine. Liver dysfunction was improved after cessation of the drug administration. Antibody to T4 was found in the serum of the patient after this event. From clinical course and laboratory data of the patient, the episode of liver damage was considered to be induced by levothyroxine. We then administrated triiodothyronine, and it did not induce liver dysfunction. Changing levothyroxine to triiodothyronine resulted in a successful clinical course in this case, as re-administration of the doubtful drug is strictly limited.

Adolescent↗

A genetic linkage map of rat chromosome 9 with a new locus for variant activity of liver aldehyde oxidase.

A genetic linkage map of rat chromosome 9 consisting of five loci including a new biochemical marker representing a genetic variation of the activity of the liver aldehyde oxidase, (Aox) was constructed. Linkage analysis of the five loci among 92 backcross progeny of (WKS/Iar x IS/Iar)F1 x WKS/Iar revealed significant linkages between these loci. Minimizing crossover frequency resulted in the best gene order: Aox-D9Mit4-Gls-Cryg-Tp53l1. The homologues of the Cryg, Gls, and Aox genes have been mapped on mouse chromosome 1 and human chromosome 2q. The present findings provide further evidence for the conservation of synteny among these regions of rat, mouse, and human chromosomes.

Aldehyde Oxidase↗

[Magnetic resonance imaging and clinical features in adults with monophasic demyelinating disease. Acute disseminated encephalomyelitis or a variant of multiple sclerosis?].

Acute disseminated encephalomyelitis (ADEM) is a widespread monophasic inflammatory disease affecting the central nervous system, that usually follows an infection or vaccination. In this study, we present an analysis of magnetic resonance imaging (MRI), cerebrospinal fluid (CSF) and clinical aspects in four patients with clinical diagnosis of ADEM. The presence of MRI demyelinating lesions was crucial, but not in itself sufficient for definitive diagnosis. Clinical and MRI follow up, in order to exclude new lesions and to reevaluate the former ones, as well as CSF, were important for the differential diagnosis with other demyelinating diseases, particularly multiple sclerosis. In addition, we have shown that early treatment with methylprednisolone after the initial symptoms was effective for improving clinical manifestations as well as for reducing MRI lesions.

Acute Disease↗

Survival of rats undergoing continuous bile drainage depends on maintenance of circadian rhythm of bile secretion.

It is very difficult to collect bile secretions from animals for extended periods of time. We compared the use of saline or water as drinking fluids to sustain the animals, which were being continuously drained of bile. Complete bile drainage was performed in 16 male Wistar rats by surgical intervention. After surgery, 8 rats were given tap water, and the other 8 were given normal saline for water. The rats that received water rapidly lost weight after bile drainage, and all died within 8 days after the operation. In contrast, all rats that drank saline maintained their body weight and survived 14 days or longer after surgery. Serum biochemistry of the rats with water intake on the third day after bile drainage revealed hyponatremia, hypochloremia, and acute renal failure resulting in hyperkalemia. In contrast, electrolyte balance and renal function were normal in the rats with saline intake, and bile was secreted continuously with a circadian rhythm. These results clearly demonstrate that saline as drinking water is essential to the replacement of lost fluids and loss of electrolytes due to bile drainage. Further, saline proved efficacious for sustaining experimental animals undergoing continuous bile collection.

Acute Kidney Injury↗

[Complement activation in citrate plasma--inhibitory effect of anticoagulants on serum complement activation].

It is generally accepted that complement activation does not proceed in EDTA- and citrate-plasma because of calcium chelation by EDTA and citrate. However, there were several cases with low CH50 level in serum and citrate plasma and normal CH50 level in EDTA plasma, suggesting that complement might be activated in citrate-plasma but not in EDTA-plasma. The present study deals with the inhibitory effect of EDTA and citrate on complement activation. CH50 was assayed in serum or plasma containing various concentrations of EDTA or citrate after incubation with latex particles bearing immunoglobulin. It was revealed that complement activation proceeded in the presence of 2.0 mmol/l of EDTA but was inhibited in the presence of 2.5 mmol/l of EDTA, while blood coagulation was inhibited in plasma containing EDTA higher than 2.0 mmol/l. As to citrate, complement activation proceeded in the presence of 25 mmol/l of citrate but was inhibited in the presence of 50 mmol/l of citrate, while blood coagulation was inhibited in plasma containing citrate higher than 6.2 mmol/l. Thus, it was indicated that, as usual plasma in clinic contains 3.5 mmol/l of EDTA or 10.9 mmol/l of citrate, complement can be activated in citrate-plasma but not in EDTA-plasma. Similar conclusion was obtained by another experiment using ordinary vacuum-type blood collection tube for EDTA-2K plasma, EDTA-2Na plasma and citrate plasma.

Anticoagulants↗

[Stenting for dissecting restenosis of the subclavian artery after balloon angioplasty: a case report].

A 51-year-old male presenting with dizziness and arm claudication was admitted to our hospital. The angiogram showed severe stenosis of the left subclavian artery accompanied by to and fro motion of left vertebral artery flow. He was treated at first by percutaneous transluminal angioplasty (PTA) resulting in satisfactory dilatation of the stenosis and transient amelioration of the symptoms. However, the symptoms recurred five months later and the angiogram revealed restenosis with subintimal dissection. We chose stent implantation as the second treatment, and, hemodynamically, it produced a good result. As some reports have suggested, because of the therapeutic limitation of surgery or PTA, stenting could be a good alternative for the treatment of such disease, since it is less invasive and safe even in patients with a wide range of systemic atherosclerosis.

Angioplasty, Balloon↗

Differences in apoptosis induced by anticancer drugs in sublines (SKG-3a, SKG-3b) from a human uterine cervical epidermoid carcinoma.

SKG-3a and SKG-3b are two distinct human uterine cervical epidermoid carcinoma cell lines derived from a single donor. We studied these two closely related cell lines from the standpoint of drug susceptibility. The growth inhibitory effects of cisplatin (CDDP), doxorubicin (ADM), etoposide (VP-16), and paclitaxel (taxol) on SKG-3a and SKG-3b cells assessed by crystalviolet dye uptake assay were almost the same. SKG-3b cells treated with CDDP, ADM, VP-16, and taxol showed the apoptotic cell death, whereas apoptosis in SKG-3a cells was not induced by these anticancer drugs. Caspase-3 activity was increased only in the SKG-3b cell lysate after treatment with CDDP, ADM, and VP-16 but was not found in the SKG-3a cell lysate. These results indicate that despite growth inhibitory effects of anticancer drugs being almost the same, there may be differences in the common signaling pathways involved in the apoptotic process between SKG-3a and SKG-3b obtained from the same tumor.

Antineoplastic Agents↗

Castability of Ti-6Al-7Nb alloy for dental casting.

Castability of Ti-6Al-7Nb alloy, CP Ti, and Co-Cr alloy was examined for mesh type and plate type specimens. The casting was carried out with a pressure type casting machine and commercial molding material. The castability of the mesh type specimen was evaluated in terms of the number of cast segments (castability index), and that of the plate type was evaluated by the area of the specimen (casting rate). X-ray images processed by a digital imaging technique were used to identify the casting porosity. The casting rate of the specimens increased with increasing thickness of the specimens. It was concluded that the castability index and the casting rate of Ti-6Al-7Nb alloy was slightly lower than that of CP Ti, and higher than that of Co-Cr alloy, were as Ti-6Al-7Nb alloy showed fewer casting porosities than CP Ti and smaller ones than Co-Cr alloy, which was advantageous for increasing the reliability of the casting properties.

Dental Alloys↗