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Biomedical subjects

K Minagawa

Publications and source records attributed to K Minagawa.

At least 37 records · Page 2Linked to original sources
PubMed1997

Setting up and features of a database of images of plastinated materials.

A database of plastinated materials was set up and distributed with a CD-ROM on the Internet. A total of 197 specimens, prepared at the Medical Museum of the University of Tokyo between 1991 and 1995, were catalogued in the database on a personal computer with commercial and original software. The database was originally designed to catalogue anatomical specimens and drawings for curators and researchers, but it also services as a worldwide digital museum.

Anatomy↗
PubMed1997

Effects of maternally administered immunoglobulin on platelet counts of neonates born to mothers with autoimmune thrombocytopenia: re-evaluation.

OBJECTIVE: Since immunoglobulin is transported across the placenta, maternal administration of it theoretically seems attractive as an antenatal treatment for a fetus. However, the effects of antenatally administered intravenous immunoglobulin (IVIG) on fetal platelet counts have been controversial. Our series of 11 cases of idiopathic thrombocytopenic purpura (ITP) and a review of previous reports are presented. A combined retrospective analysis to know whether maternal response to IVIG is associated with improvement of fetal thrombocytopenia was conducted. METHODS: IVIG was given to 11 steroid refractory pregnancies with ITP. Good maternal response to the therapy was defined as an increase in the platelet count to greater than 50 x 10(9)/L after completion of the IVIG infusion. Neonatal platelet counts of the umbilical cord were performed just after birth and followed-up for at least the first week of life. RESULTS: Seven of the 11 neonates had thrombocytopenia of less than 100 x 10(9)/L, and two of them had severe thrombocytopenia of less than 50 x 10(9)/L. Two out of two neonates born to mothers with a good response to IVIG were thrombocytopenic; whereas five out of nine neonates born to mothers with a poor response were thrombocytopenic. The combined retrospective analysis of our results and published reports have shown that fetal thrombocytopenia was not associated with the maternal response to IVIG but with the level of immunoglobulin G of neonates at birth. Passive thrombocytopenia was more frequently observed in neonates with normal levels of immunoglobulin G than those with elevated levels. CONCLUSION: This combined analysis confirmed the proposed hypothesis that the lack of effect of maternally administered IVIG on fetal platelet counts may mainly be attributed to the insufficient therapeutic level of transferred immunoglobulin G in the cord blood.

Female↗
PubMed1996

Schizostatin, a novel squalene synthase inhibitor produced by the mushroom, Schizophyllum commune. II. Structure elucidation and total synthesis.

Schizostatin (1) has been isolated as a potent and selective inhibitor of squalene synthase. Its structure has been determined using spectroscopic methods: the compound is shown to be a diterpenoid which has a trans-dicarboxylic acid moiety. Total synthesis of schizostatin (1) was achieved by the highly regio- and stereoselective coupling reaction of an allylic bromide with a barium reagent. The Z-isomer 16 was also prepared using the stereoselective syn-addition of an organocopper reagent to acetylenedicarboxylate.

Enzyme Inhibitors↗
PubMed1995

Muscle involvement in congenital insensitivity to pain with anhidrosis.

A patient with congenital insensitivity to pain with anhidrosis, who had characteristic clinical features and biopsied sural nerve, is presented. Nerve pathology findings indicated a loss of the small myelinated and unmyelinated fibers. Biopsied muscle disclosed a marked variation in fiber size, some small fibers with central nuclei, and a small number of small angulated fibers, consistent with neurogenic and myogenic changes. Many patients with congenital insensitivity to pain with anhidrosis had muscle weakness and absent or decreased deep tendon reflexes with normal nerve conduction velocity. We confirmed that lack of small myelinated fibers in motor neurons resulted in a striking change of muscle in our patient.

Biopsy↗
PubMed1994

[Knowledges of foodstuffs in relation to adult diseases in Japanese students--results from Japan Know Your Body Study].

As part of developing the Know Your Body (KYB) program for Japan, a questionnaire survey was administered assessing knowledge, attitudes, and behavior regarding cigarette smoking, alcohol drinking, dietary lifestyle and exercise. The subjects, about 13,000 in total, were students in elementary, junior and senior high schools in 9 prefectures. The main results concerning knowledge of foods that cause or prevent adult diseases are as follows: 1) Correct responses on the relationship of excessive salt intake and hypertension were made by 39% of males and 41% of female in the fifth grade of elementary school. In the third grade of junior high school, the percentage of correct answer for the same question increased to 80% of males and females, and in the third grade of senior high school, it rose to 90% of males and 91% of females. No clear sex difference was seen in all the grades of school. 2) Less than 23% of the students from the first to fourth grade of elementary school knew the word "cholesterol" and could distinguish high cholesterol foods. In the sixth grade of elementary school, more than 50% of students knew the word "cholesterol". In the third grade of junior high school, more than 50% of students could distinguish high cholesterol foods correctly and recognized the relationship of excessive cholesterol intake to heart disease. These results provide a basis for determination of the age for introducing nutrition education. 3) The percentage of correct answers for distinguishing green-yellow vegetables, showed a clear sex differential. The percentage of correct answers concerning dietary fiber was 75% for males and 81% for females in senior high school.

Adolescent↗
PubMed1993

Change of the higher order structure of DNA induced by the complexation with intercalating synthetic polymer, as is visualized by fluorescence microscopy.

The electrophoretic movement and Brownian motion of T4DNA, lambda DNA and their complexes with polyacrylamide (PAAm) via intercalative unit from 5-[(4-acryloylamino)phenyl]-3-amino-7-(dimethylamino)-2-methylp henazinium chloride were observed using fluorescence microscopy. It was found that T4DNA/PAAm complex migrates slower than T4DNA alone in gel electrophoresis, although they exhibit similar conformational change during the migration. Quantitative analyses of the translational diffusion of the lambda DNA and its complex in solution demonstrate that the DNA molecules extend due to intercalative binding of PAAm, suggesting the pseudo-grafting structure of the complex.

Acrylic Resins↗
PubMed1993

Lithocholate-3-O-glucuronide-induced cholestasis. A study with congenital hyperbilirubinemic rats and effects of ursodeoxycholate conjugates.

The mechanism of lithocholate-3-O-glucuronide-induced cholestasis is unknown. In this study, we investigated the cholestatic effects of this agent in a congenital hyperbilirubinemic rat, EHBR. We also studied the effects of ursodeoxycholate-3-O-glucuronide and tauroursodeoxycholate on lithocholate-3-O-glucuronide-induced cholestasis in rats. Lithocholate-3-O-glucuronide, administered at the rate of 0.1 mumol/min/100 g for 40 min, a cholestatic dose in control rats, failed to cause cholestasis in EHBR, and biliary lithocholate-3-O-glucuronide excretion was delayed. Biliary concentrations of this agent did not correlate with the severity of cholestasis. Both tauroursodeoxycholate and ursodeoxycholate-3-O-glucuronide, infused at the rate of 0.2 mumol/min/100 g for 120 min, completely inhibited cholestasis induced by lithocholate-3-O-glucuronide administered at the rate of 0.1 mumol/min/100 g for 40 min. Only tauroursodeoxycholate enhanced biliary lithocholate-3-O-glucuronide excretion. These findings indicate that lithocholate-3-O-glucuronide-induced cholestasis is induced by damage at the level of the bile canalicular membrane. Ursodeoxycholate-3-O-glucuronide inhibits this cholestasis, possibly by inhibiting the access of lithocholate-3-O-glucuronide to the bile canalicular membrane.

Animals↗
PubMed1993

Dehatrine, an antimalarial bisbenzylisoquinoline alkaloid from the Indonesian medicinal plant Beilschmiedia madang, isolated as a mixture of two rotational isomers.

Through bioassay-guided separations of the chemical constituents of the Indonesian medicinal plant Beilschmiedia madang BL. a bisbenzylisoquinoline alkaloid was obtained as the major antimalarial principle. The physicochemical properties of the alkaloid were consistent with the proposed structure of dehatrine. However, the alkaloid isolated by us was shown to be a mixture of two rotational isomers. The X-ray crystallographic analysis of 1 has shown that two rotamers are incorporated in a single crystal in 1:1 ratio. The complex NMR spectrum of 1 has also been defined as a mixture of two rotamers by extensive use of 2D (COSY and COLOC) techniques. Dehatrine has been shown to significantly inhibit the growth of cultured Plasmodium falciparum K1 strain (cholorquine resistant) with similar activity to quinine.

Alkaloids↗
PubMed1993

Aquastatin A, an inhibitor of mammalian adenosine triphosphatases from Fusarium aquaeductuum. Taxonomy, fermentation, isolation, structure determination and biological properties.

A new inhibitor of mammalian adenosine triphosphatases, designated aquastatin A, has been isolated from a fungus identified as Fusarium aquaeductuum. The structure of this compound has been determined by MS and NMR analyses. It inhibits Na+/K(+)-ATPase with an IC50 value of 7.1 microM, and H+/K(+)-ATPase with an apparent IC50 value of 6.2 microM.

Adenosine Triphosphatases↗
PubMed1992

Opposite effect between intercalator and minor groove binding drug on the higher order structure of DNA as is visualized by fluorescence microscopy.

Fluorescence microscopy is applied to obtain the information on the change of the higher-order structure of giant DNA molecules in an aqueous solution. Using T4 DNA, it becomes clear that ethidium bromide, an intercalator, tends to extend the DNA, whereas minor groove binding drugs such as 4',6-diamidino-2-phenylindole and Hoechst 33258 tend to contract the DNA. These changes of higher-order structure have been quantitatively evaluated as the changes in persistent length together with the change of contour length. It is also confirmed that the persistent length obtained by use of fluorescence microscopy is reliable enough comparing with those reported for the shorter DNA by use of light scattering.

Bacteriophage T4↗
PubMed1992

Effects of ursodeoxycholate, its glucuronide and disulfate and beta-muricholate on biliary bicarbonate concentration and biliary lipid excretion.

We previously reported that high-dose ursodeoxycholate (UDC) infusion in rats resulted in extensive glucuronidation of UDC, and speculated that the glucuronidation causes bicarbonate-rich hypercholeresis induced by UDC (Takikawa, H., Sano, N., Narita, T. and Yamanaka, M. Hepatology 1990; 11: 743-749). To test this hypothesis, UDC, UDC-3-O-glucuronide, UDC-3,7-disulfate and beta-muricholate were separately and intravenously infused into rats (1 mumol/min per 100 g), and biliary bicarbonate concentration was measured. The effects of these bile acids on biliary lipid secretion were also studied. All four bile acids increased bile flow and biliary bile acid excretion. UDC and beta-muricholate significantly increased biliary bicarbonate concentration, whereas UDC glucuronide and disulfate did not. Independence of UDC glucuronide excretion and biliary bicarbonate concentration was also confirmed in EHBR, a hyperbilirubinemic mutant Sprague-Dawley rat. In this case biliary bicarbonate concentration also increased in spite of the absence of UDC glucuronide in the bile after UDC infusion. Biliary phospholipid secretion was increased with UDC, unchanged with beta-muricholate, and decreased with UDC glucuronide and disulfate. Biliary cholesterol secretion was increased with UDC, unchanged with beta-muricholate and UDC glucuronide, and decreased with UDC disulfate. These data indicate that glucuronidation is not the cause of bicarbonate-rich hypercholeresis induced by UDC but that glucuronidation and sulfation change the effect of UDC on biliary lipid secretion.

Animals↗
PubMed1992

Dynamical conformational change of DNA induced by synthetic polymers: direct observation by fluorescence microscopy.

Brownian motion and Higher-order structure of DNA molecules complexed with synthetic polymers: poly-L-arginine (pArg) and polyacrylamide (pAAm), were observed using fluorescence microscopy. Quantitative analyses of the conformation and motion of the complexes demonstrate that these two polymers influence the structure of DNA molecules in an opposite way. The electrostatic binding of pArg induces contraction of DNA, whereas the intercalative pseudo-grafting of pAAm extends DNA.

Acrylic Resins↗
PubMed1991

Direct observation of the biphasic conformational change of DNA induced by cationic polymers.

The interaction between T4 DNA and basic polypeptides was observed using fluorescence microscopy. Free DNA molecules exhibited random Brownian motion accompanying the conformational change. With the addition of polycation, such as histone and polyarginine, DNA molecules tended to shrink to become spherical shapes. The persistent lengths and the distributions of long axis lengths of DNA-polyarginine complexes were determined from the video images at various polyarginine concentrations. It is demonstrated that the conformation of DNA changes in a biphasic manner in the presence of polyarginine.

Cations↗
PubMed1991

[Standardization of definitions concerning smoking behavior among Japanese adolescents--results from the Japan Adolescent Smoking Survey (JASS)].

The aim of the Japan Adolescent Smoking Survey (JASS) is to standardize the definitions of smoking behavior among Japanese adolescents together with measurement methods and questionnaires concerned. A study of 9921 school children aged 9 to 18 years in 17 elementary schools, 16 junior high schools and 18 senior high schools in 9 prefectures, was conducted between June and July of 1989, to determine the relationship between actual smoking behavior during the past month or year and the "self-referent label" concerning their smoking status. The main results were as follows: 1) The percentage of those who smoked at least one cigarette during the past month showed a high degree of similarity to the percentage of those who referred to themselves as "regular smokers" or "occasional smokers". 2) Less than 10% of students who identified themselves as "never smokers" or "ex-smokers" smoked at least one cigarette during the past month, while more than 80% of students who referred to themselves as "regular smokers" or "occasional smokers" smoked during the past month. 3) On the whole, those who smoked 20 or more cigarettes during the past month referred to themselves as "regular smokers"; those who smoked between 2 and 19 cigarettes as "occasional smokers"; those who smoked 1 cigarette as "ex-smokers"; those who did not smoke during the past month as "never smokers". 4) The definition where students who smoked one cigarette during the past month are classified as a category of smoker, displayed a high level of sensitivity and specificity for all school-level groups and for both sexes.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1991

[Smoking and alcohol drinking behavior among Japanese adolescents--results from "Japan Know Your Body Study"].

The "Japan Know Your Body Study" (JKYB) is an example of collaborative activities of technology transfer carried out in Japan in several phases. The first phase is a needs assessment and data collection survey and it was administered during 1989. A survey was conducted throughout 9 prefectures in Japan with participation by 49 schools. Subjects were students in elementary, junior and senior high schools who ranged in age from 6 to 18 years. Participants, 12,892 in total, completed a survey on knowledge, attitude and behavior regarding cigarette smoking, alcohol drinking, diet, exercise and so on. The main results concerning cigarette smoking and alcohol drinking behavior were as follows: 1) The percentage of monthly male smokers rose remarkably from 8% in the third grade of junior high school to 37% in the third grade of senior high school, while that of female smokers showed a slow rise from 3% to 15%. The sex difference for smoking behavior was clear among senior high school students. 2) Smoking rates increased in proportion to the numbers of parents, siblings and friends who smoked. Above all, smoking behavior of friends was strongly related. Among senior high school students, for example, 50% of males and 46% of females who had two or more smoking friends were smokers, as compared to 5% of males and 2% of females with no smoking friends. 3) The percentage of monthly drinkers rose at a steady pace from 13% of males and 7% of females in the fifth grade of elementary schools to 59% of males and 50% of females in the third grade of senior high schools. The sex difference for alcohol drinking behavior among senior high school students, while statistically significant, was not as pronounced as that for smoking behavior. These results suggest that tobacco- and alcohol-use prevention programs should be introduced in elementary schools and those programs should include components relating to the social influences of parents, siblings and friends.

Adolescent↗
PubMed1991

Conformational dynamics of DNA affected by intercalation and minor groove binding: direct observation of large DNA.

Using fluorescence microscopy, we have observed moving DNA molecules in solution and analyzed the "higher-order" structure in a quantitative manner. It was found that EB (ethidium bromide), an intercalator, has the effect to increase the persistent length. In other words, EB expands DNA. Whereas, DAPI (4',6-diamidino-2-phenylindole), a minor groove binding drug, decreases the persistent length. It is demonstrated that the direct observation of DNA molecules with fluorescence microscopy is quite useful to study the interaction of various chemical compounds with DNA molecules.

Bacteriophage T4↗