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Biomedical subjects

K Mochida

Publications and source records attributed to K Mochida.

At least 73 records · Page 4Linked to original sources
PubMed1993

Effects of cytokines, anti-cancer agents and cocarcinogen on DNA synthesis in hair bulb cells.

We analysed the effects of cytokines, anti-cancer agents and cocarcinogen on DNA synthesis in human hair germinative cells cultured in serum-free media. Epidermal growth factor and gamma interferon were found to inhibit DNA synthesis slightly, while strong inhibition was demonstrated by doxorubicin, cytosine arabinoside and tetradecanoyl-phorbolacetate. Basic fibroblast growth factor had very little influence on DNA synthesis. This organ culture model in serum-free media is a useful method by which to examine the effects of various cytokines and drugs on DNA synthesis in hair germinative cells and/or to study the pathogenesis of various alopecia diseases.

Antineoplastic Agents↗
PubMed1993

Evaluation of cervical diskography in pain origin and provocation.

The purpose of this article is to analyze the role of cervical diskography as a diagnostic method via reproduced pain. A nonionic contrast medium (Iohexol) that does not harm normal tissue was used in this series to prevent false-positive provocative pain. One hundred forty-four patients (128 with cervical spondylotic myelopathy, eight with cervical spondylotic radiculopathy, and eight with cervical spondylotic amyotrophy) were studied. Among 72 patients in the symptomatic neck pain group who complained of neck pain before diskography, 65% showed reproduced pain. However, in the control group (neurologic symptoms only) 50% of the patients complained of provocative neck pain during dye injection. These results demonstrated that this provocation technique appeared unreliable for diagnosing symptomatic disk levels.

Adult↗
PubMed1993

Arginine-dependent generation of reactive nitrogen intermediates is instrumental in the in vitro killing of protoscoleces of Echinococcus multilocularis by activated macrophages.

The interaction between protoscoleces of Echinococcus multilocularis and activated murine macrophages was examined in this study. Marked protoscolicidal activity was displayed by peritoneal macrophages (PM) activated with interferon-gamma (IFN-gamma), or IFN-gamma plus lipopolysaccharide. Pretreatment of the parasites with heat-inactivated specific murine infection serum, but not with normal serum rendered them more susceptible to PM killing. NG-monomethyl-L-arginine, a competitive inhibitor of L-arginine completely inhibited the killing activity of activated PM, while reconstitution of arginine-free medium with L-arginine restored the killing properties of the activated PM. The results show that activated PM have the ability to kill E. multilocularis protoscoleces in vitro and suggest that reactive nitrogen intermediates (RNI) play an important role in the mechanism. An oxygen-mediated mechanism did not appear to play a role because scavengers of reactive oxygen species did not reduce the killing activity. The arginine-dependent killing mechanism was enhanced by superoxide dismutase (SOD), probably because SOD might prolong the effect of nitric oxide. Secretion of RNI by activated macrophages may be capable of a significant role in preventing of the dissemination of E. multilocularis infection in vivo.

Animals↗
PubMed1993

Contact allergies to topical corticosteroids.

The patient, a 34-year-old Japanese woman who noticed worsening of her rash after using topical corticosteroid preparations on her neck, was patch tested for both commercial preparations and corticosteroids themselves. The patch test results revealed that she had a contact allergy to gold, oxytetracycline, and 2 types of corticosteroid (acetonides and esters) in 7 compounds (betamethasone valerate and dipropionate, hydrocortisone butyrate and hydrocortisone butyrate propionate, amcinonide, budesonide, and fluocinonide).

Administration, Cutaneous↗
PubMed1992

Organ culture conditions of human hair follicles.

Experimental results revealed that although [3H]thymidine uptake in the hair bulb increased time dependently for 12 days under normal culture conditions (95% air-5% CO2 at 37 degrees C), striking morphological changes occurred in the hair bulb cells as demonstrated by histological findings. As such, organ culture conditions applicable to human hair follicles were studied utilizing observations from both histology and DNA synthesis. We found that culture conditions of 95% O2-5% CO2 at 31 degrees C were superior when compared to normal culture conditions for cultures of human hair follicles when attempting to maintain the normal morphology of hair germinative cells. The hair bulb and the germinative cells successfully maintained their normal morphology throughout the 96 and 48 h culture period, respectively. Autoradiographs of [3H]thymidine-labeled follicles showed localization in the germinative cells below Auber's critical line. Hair bulb DNA synthesis increased time dependently for 96 h after culture initiation. Under conditions of 95% O2-5% CO2 at 31 degrees C, the synthesis of DNA in hair germinative cells was observed. Such an organ culture method may prove useful for studies on the human hair growth mechanism.

Autoradiography↗
PubMed1992

Production of dihydrofolate reductase by cloned Escherichia coli and its application to asymmetric synthesis of l-leucovorin.

We have investigated culture conditions for production of dihydrofolate reductase by Escherichia coli harboring a high expression plasmid, pTP64-1. Sorbitol addition and pH control were effective for the production of the enzyme in a jar fermentor. The enzyme was purified from a cell-free extract by column chromatographies on DEAE-Cellulofine and Superose Prep12 and showed a single band on SDS-polyacrylamide gel electrophoresis. The reduction of 200 mM dihydrofolate to 6(S)-tetrahydrofolate, an intermediate for l-leucovorin synthesis, was complete in 2 hr under anaerobic conditions, using 1.5 units/ml of the purified enzyme.

Chromatography, DEAE-Cellulose↗
PubMed1992

NADPH regeneration by glucose dehydrogenase from Gluconobacter scleroides for l-leucovorin synthesis.

A new process for (6S)-tetrahydrofolate production from dihydrofolate was designed that used dihydrofolate reductase and an NADPH regeneration system. Glucose dehydrogenase from Gluconobacter scleroides KY3613 was used for recycling of the cofactor. The reaction mixture contained 200 mM dihydrofolate, 220 mM glucose, 2 mM NADP, 14.4 U/ml dihydrofolate reductase, and 14.4 U/ml Glucose dehydrogenase, and the reaction was complete after incubation at pH 8.0, and 40 degrees C for 2.5 hr. With (6S)-tetrahydrofolate as the starting material, l-leucovorin was synthesized via a methenyl derivative. The purity of the l-leucovorin was 100%, and its diastereomeric purity was greater than 99.5% d.e. as the (6S)-form.

Folic Acid↗
PubMed1992

[An experimental study on direct nerve implantation into denervated muscle--the functional recovery and the site of implantation].

The functional recovery of the newly formed endplates in the muscle reinnervated by direct neurotization was studied grossly, electrophysiologically and histologically in the anterior tibialis muscle of rats. The proximal stump of the tibial nerve was severed at the ankle level and was embedded at the level of distal one fifth of the muscle where no endplates were detected just after denervation of the muscle. Histologically, the accumulations of acetylcholinesterase activity were detected 4 weeks after neurotization. Electrophysiological study using a multi-channel electrode revealed the two-directional propagation of action potentials 8 weeks after neurotization, and the propagation started from no other sites than the nerve-implantation. The muscle tension revealed 42% of the contralateral muscle 52 weeks after neurotization. These results concluded that the function of the newly formed endplates spread throughout the muscle and it was lasting.

Action Potentials↗
PubMed1992

Adenocarcinoma in Meckel's diverticulum: report of a case and review of 30 cases in the English and Japanese literature.

A 54-yr-old man who complained of abdominal pain was found to have an adenocarcinoma arising in Meckel's diverticulum, as preoperatively diagnosed with 99mTc-pertechnetate scintigraphy. Angiography of the superior mesenteric artery revealed multiple branched arteries and tumor stain, but the vitelline artery was not clearly identified. Surgery revealed that the tumor had invaded the urinary bladder and the ileum, including the diverticulum, and the bladder had to be partially resected. Histopathological examination of the lesion revealed a diverticulum containing normal small bowel mucosa, ectopic normal gastric tissue, and adenocarcinoma. In a review of 30 cases of adenocarcinoma in Meckel's diverticulum in the English and Japanese literature, our case was the first to be diagnosed preoperatively.

Adenocarcinoma↗
PubMed1991

Prognostic factors in Japanese patients with colorectal cancer: the significance of large bowel obstruction--univariate and multivariate analyses.

In order to define prognostic factors in colorectal carcinoma, univariate and multivariate analyses were carried out on data from 113 Japanese patients treated in a typical general hospital in Japan. In the univariate analysis, a poor prognosis was seen in those with poorly differentiated adenocarcinoma, in tumors that perforated the visceral peritoneum or that invaded directly other organs or structures (T4), in metastasis to the nodes along the main vascular pedicle (N3), in lymphatic permeation, in blood vessel invasion, in peritoneal dissemination, in Dukes C stage, and in those with lesions presenting with large bowel obstruction. Of these, only lymph node metastasis and peritoneal dissemination had an independent prognostic significance when a multivariate Cox analysis was performed. The significant risk factors related to an obstructing tumor were determined by multivariate logistic regression analysis. The significant variables were patient's age, nodal involvement and peritoneal dissemination. Since lymph node metastasis and peritoneal dissemination proved significant in both multivariate analyses, we propose that the presence of large bowel obstruction is not an independent prognostic factor in patients with colorectal carcinoma. In poor-risk patients who have an obstructing tumor, a staged operation should be attempted for definitive curative surgery.

Adenocarcinoma↗
PubMed1991

The development of the uteroplacental vascular system in the golden hamster Mesocricetus auratus.

The development of the uteroplacental vasculature in the golden hamster was studied by vascular casting and India ink injection methods. The hamster placenta usually has three sets of uteroplacental arteries and its maternal segment is derived from the medial arterial division of the non-pregnant uterus. The maternal segment consists of the spiral artery in the endometrium and the vascular knot in the mesometrium. The spiral arteries start developing on Day 5, simultaneously with the endometrial decidual reaction of the mesometrial side. The chorioallantoic placenta of the golden hamster is the so-called labyrinthine haemochorial type. The formation of the haemochorial placenta begins as early as Day 7, when maternal blood drains into the uterine lumen to form the maternal blood space. In this space, the maternal blood starts flowing on Day 8 and a direct contact with the chorion containing fetal capillaries is achieved on Day 9. The labyrinthine feature, in which the direction of flow of the maternal and fetal blood is in opposite directions, is achieved on Day 10. This countercurrent system functions through the central arterial space, the fetal segment of the uteroplacental artery which leads the maternal blood to the antimesometrial surface of the labyrinth.

Animals↗
PubMed1990

Chemo-enzymatic synthesis of optically pure l-leucovorin, an augmentor of 5-fluorouracil cytotoxicity against cancer.

Optically pure l-leucovorin was synthesized on a large scale by the combination of chemical and enzymatic processes. After reduction of folate with zinc, dihydrofolate was reduced asymmetrically to (6)-tetra-hydrofolate by use of dihydrofolate reductase from E. coli C600/pTP600, with simultaneous NADPH cofactor recycling using glucose dehydrogenase from Gluconobacter scleroideus KY3613. Calcium l-leucovorin.4H2O (113 g) was obtained from (6S)-tetrahydrofolate via 5,10-methyenyltetrahydrofolate by formylation, reflux, addition of calcium ions and floricil column chromatography, with an overall yield of 50% based on folate. The l-leucovorin showed optical purity of 99.9% de as (6S)-form.

Escherichia coli↗
PubMed1989

Synthesis and biological evaluation of 3-chloro-1-carbacephem compounds.

The 3-chloro-1-carbacephem nucleus was prepared for the first time from a 3H-1-carbacephem compound through a sequence of reactions involving addition of thiophenol, oxidation of sulfide to sulfoxide, and alpha-chlorination of the sulfoxide, followed by elimination of phenylsulfinic acid. The 2-beta-methyl analog was similarly prepared, but the 2 alpha-methyl analog was not obtained. Optical resolution of the 3-chloro-1-carbacephem compound was achieved by the employment of penicillin acylase. That is, the 7-phenylacetamido derivative was enantioselectively hydrolyzed to afford the optically active 7-amino-3-chloro-1-carbacephem compound. Carbacefaclor, the carbacephem analog of cefaclor, was directly and efficiently prepared by enzymatic phenylglycylation of the racemic 7-amino-3-chloro-1-carbacephem compound by using immobilized penicillin acylase. Carbacefaclor thus prepared exhibited comparable antibacterial activity against most gram positive bacteria tested and higher activity against typical gram negative bacteria as compared with cefaclor. Moreover, carbacefaclor possessed remarkably high chemical stability.

Cephalosporins↗
PubMed1989

In vitro and in vivo antibacterial activity of KT3777, a new orally active carbacephem.

KT3777 is a novel carbacephem antibiotic structurally identical to cefaclor (CCL), except that the sulfur atom of position 1 of the cephem nucleus has been replaced by carbon. KT3777 was investigated for in vitro and in vivo antibacterial activities in comparison with CCL, cephalexin (CEX) and amoxicillin. The MIC50 of KT3777 ranged from 0.2 to 3.13 micrograms/ml for clinical isolates of Staphylococcus aureus, Streptococci, Escherichia coli, Klebsiella pneumoniae, Proteus mirabilis, Haemophilus influenzae, and Neisseria gonorrhoeae. KT3777 possessed an antibacterial spectrum and potency similar to that of CCL. However, against E. coli and K. pneumoniae, KT3777 was about twice as active as CCL. KT3777 was more active than CEX against all strains tested. Killing-curve studies demonstrated bactericidal activity of KT3777 at concentrations above the MIC. KT3777 showed good affinity for penicillin-binding proteins 1A, 1Bs, 3 and 4 of E. coli NIHJ JC-2. The protective effect of KT3777 against systemic infections in mice was comparable to that of CCL with a few exceptions and about 3 to 7 times greater than that of CEX. KT3777 also proved effective against localized infections such as acute pneumonia and ascending urinary tract infections in mice.

Administration, Oral↗
PubMed1989

Synthesis and antibacterial activity of novel 3-substituted carbacephems.

A series of novel 3-heterocyclothio substituted carbacephems having phenylglycyl side chain have been prepared starting from 3-H carbacephem. The compounds exhibit better chemical stability than the corresponding cephalosporin and strong activity against Gram-negative and Gram-positive organisms including Enterococcus faecalis.

Cephalosporins↗