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Biomedical subjects

M Umetsu

Publications and source records attributed to M Umetsu.

At least 19 recordsLinked to original sources
PubMed2006

A case of reversed pituitary dysfunction with intrasellar mass.

Hypopituitarism can be caused by tumor, inflammation, granuloma and injuries. Once pituitary function is disturbed, hormone replacement therapy is necessary for the remaining life span in most cases. We have experienced a rare case of a unique intrasellar mass associated with pituitary dysfunction in which both spontaneously reversed. A 61-yr-old woman developed hypoadrenalism and central diabetes insipidus (cDI). Magnetic resonance (MR) imaging revealed a lobular, strong hypointense lesion with spotty signal in the middle of the hypophysis. This spotty lesion showed isointensity on T1- and high-intensity on T2-weighted MR images. The spotty signal as well as the normal pituitary lobe were enhanced by the administration of gadolinium. As replacement therapies for hypoadrenalism and cDI, 10 mg of hydrocortisone and 2.5 microg of desmopressin acetate were prescribed. Three months later, slight shrinkage of intrasellar mass and spontaneous improvement of pituitary functions were found. Hydrocortisone was then discontinued. Furthermore, because polyuria and polydipsia were improved nine months later, desmopressin acetate was stopped. Currently, the intrasellar mass continues to shrink, and the patient shows no symptoms without medication. Based upon the unique features of MR images, we suspect that the origin of the mass is an intrasellar hemangioma.

Diabetes Insipidus, Neurogenic↗
PubMed2005

A rare case of Gitelman's syndrome presenting with hypocalcemia and osteopenia.

Gitelman's syndrome (GS), an autosomal recessive disorder caused by a defect of the thiazide-sensitive Na-Cl cotransporter (TSC) at the distal tubule, is characterized by hyperreninemic hyperaldosteronism with normal or low blood pressure, hypokalemia, metabolic alkalosis, hypomagnesemia and hypocalciuria. An 18-yr-old Japanese man was admitted to our hospital with a history of muscle weakness and transient tetanic episodes. He showed hypocalcemia in addition to hypokalemia, severe hypomagnesemia, hypocalciuria and hyperreninemic hyperaldosteronism with normal blood pressure. Furthermore, bone mineral density at the lumbar spine revealed osteopenia. A diagnosis of GS was made on the basis of clinical features, laboratory data and renal function test. The electrolyte imbalance was corrected and bone mineral density was slightly increased with chronic treatment of magnesium and potassium salts. Genetic analysis revealed that TSC gene of the patient has a heterozygous C to A nucleotide substitution at position 545 in exon 4, which causes a threonine (Thr) to lysine (Lys) substitution at position 180. This is a rare case of GS with hypocalcemia and osteopenia which could be caused by severe hypomagnesemia.

Adolescent↗
PubMed2005

A sero-epidemiological survey of gelatin sensitization in young Japanese children during the 1979-1996 period.

Recently, an increasing number of adverse reactions in children inoculated with live attenuated virus vaccines containing gelatin have been reported. However, the distribution, magnitude and rate of gelatin sensitization in the Japanese population have not been established. Here, the purpose was to investigate the distribution of children with positive gelatin immunoglobulin G (IgG) and/or IgE in Japan and to ascertain whether the incidence of positive antigelatin antibody cases among the general population, as reflected in the sample employed here, has been increasing during the period in question. The presence of IgE and IgG antibodies were measured against gelatin in 1600 panel sera collected from different age groups of Japanese children in Hokkaido/Sapporo from 1979 through 1996. Among the subjects, 39 had gelatin IgG- and/or IgE-positive sera, and these were correlated with the time of obtaining the sera as well as with the age of the subjects. The older the subject and the later the period, the higher the sero-incidence. Japanese children have become increasingly sensitized to gelatin, especially since the mid-1990s.

Child, Preschool↗
PubMed2001

Characteristics of macrolide-resistant Mycoplasma pneumoniae strains isolated from patients and induced with erythromycin in vitro.

Some patients with Mycoplasma pneumoniae infection are clinically resistant to antibiotics such as erythromycin, clarithromycin, or clindamycin. We isolated M. pneumoniae from such patients and found that one of three isolates showed a point mutation in the 23S rRNA gene. Furthermore, 141 EM-sensitive clinical isolates of M. pneumoniae were cultured in broth medium containing 100 microg/ml of erythromycin (EM). Among 11 EM-resistant strains that grew in the medium, point mutations in the 23S rRNA were found in 3 strains at A2063G, 5 strains at A2064G and 3 strains at A2064C. The relationship between the point mutation pattern of these EM-resistant strains and their resistance phenotypes to several macrolide antibiotics was investigated.

Anti-Bacterial Agents↗
PubMed2000

Interaction of photosynthetic pigments with various organic solvents 2. Application of magnetic circular dichroism to bacteriochlorophyll a and light-harvesting complex 1.

Magnetic circular dichroism (MCD) and absorption spectra of metal bacteriochlorin complexes have been measured on bacteriochlorophyll (BChl) a in various solvents and different forms of light-harvesting complexes 1 (LH1 complexes). In hydrophilic organic solvents, the MCD intensity of the Q(y)(0-0) transition of BChl a was sensitive to the wavelength of absorption maximum of Q(x)(0-0), and the ratio of MCD Q(y)(0-0) intensity to the dipole strength (B/D) was inversely proportional to the difference in energy between the Q(x)(0-0) and Q(y)(0-0). The similar correlation has been observed in metal chlorin derivatives as previously reported. The correlation depends on the coordination number of the Mg atom in BChl a and the molecules ligating to it. In a hydrophobic solvent such as carbon tetrachloride (CCl(4)), however, the correlation did not hold because of the existence of aggregates. Hence, the correlation between the values of B/D and the energy difference can be used to estimate the type and number of the molecules ligated to the Mg atom and to disclose the existence of aggregated pigments. We further apply the correlation to the LH 1 complex treated with n-octyl beta-D-glucopyranoside.

Bacterial Proteins↗
PubMed2000

Therapeutic effect of clarithromycin for respiratory-tract infections in children caused by Chlamydia pneumoniae. Research Group of Sapporo for Pediatric Chlamydial Infections.

Children infected with Chlamydia pneumoniae sometimes experience lower respiratory tract infections such as pneumonia and bronchitis. Although numerous anti-microbial compounds have been reported to be active against the organism, most of them have not been in a clinical trial in infants and children with C. pneumoniae infection. Clarithromycin has been shown to express anti-chlamydial effects in vitro. In this study, we evaluated the clinical anti-C. pneumoniae properties of clarithromycin in children with mainly lower respiratory tract infection. We administered clarithromycin orally to 21 infants and children at a dose of 10-15 mg/kg/day divided into two or three doses for 4-21 days. Clinical symptoms, roentgenographic and laboratory abnormal findings improved. The overall clinical efficacy rate was 85.7% (18 of 21 cases). Administration of clarithromycin was considered to be a suitable treatment for improving lower respiratory infections in infants and children caused by C. pneumoniae.

Administration, Oral↗
PubMed1999

Two-Layer Structure of Microcapsule Membrane as Predicted from Electrophoretic Studies.

Four types of hydrophilic gel microcapsules containing water have been prepared by an interfacial polymerization method. Each type of microcapsules has membranes of different compositions. Using three kinds of monomers, N,N-dimethylacrylamide (DMAAm), 4-aminomethylstyrene (AmSt), and N,N-dimethylaminopropylacrylamide (DMAPAA), two types of water-soluble copolymers with different compositions having primary and tertiary amino groups were obtained. Two more types of copolymers were synthesized by copolymerization of alpha-acryloxy-omega-methoxy-poly(ethylene glycol) (a-PEG) with the above two kinds of monomer mixtures. These copolymers were polymerized with terephthaloyldichloride at the water/oil interface to prepare four types of microcapsules containing water. By electrophoretic mobility measurements of these microcapsules and the analyses of the data, it was found that the surface layer of the microcapsule membranes were composed of two sublayers, each of which has different charge density and softness. The outer sublayer was negatively charged and inner sublayer was positively charged. By PEGylation, the charge density in the outer sublayer decreased, while that in the inner sublayer was not affected. Also, the surface layer became softer by PEGylation. The effects of membrane composition upon the swellability of the microcapsule membrane were studied. It was found that the asymmetrical structure of the microcapsule membranes causes the nonuniform distribution of charges and then the swellability of the microcapsule membrane changes depending on the permittivity of the dispersing medium. Copyright 1999 Academic Press.

Journal Article↗
PubMed1999

Interaction of photosynthetic pigments with various organic solvents. Magnetic circular dichroism approach and application to chlorosomes

Magnetic circular dichroism (MCD) and absorption spectra have been measured on three intact photosynthetic pigments with the chlorin ring as macrocycle: chlorophyll a, bacteriochlorophyll c and d, in various hydrophilic organic solvents. The MCD intensity of a Qy(0-0) transition for the Mg chlorin derivative was sensitive to the coordination state of the central Mg atom by the solvent molecules. The coordination number has been characterized in terms of the relationship between the ratio of Qy(0-0) MCD intensity to its dipole strength (B/D) and the difference in energies of Qx(0-0) and Qy(0-0) transitions. This relationship depends not only on the coordination number of the magnesium (Mg) atom but also on the coordination interaction of the solvent molecules to the Mg atom, and can clarify the spectroscopic change of chlorosomes by alcohol treatment. We propose that the correlation between the MCD intensity of Qy(0-0) transition and the energy difference can be used as a new measure for determining the coordination number of the Mg atom and for estimating the interaction strength of the Mg atom with solvent molecules.

Journal Article↗
PubMed1999

Identification of a new variable sequence in the P1 cytadhesin gene of Mycoplasma pneumoniae: evidence for the generation of antigenic variation by DNA recombination between repetitive sequences.

A Mycoplasma pneumoniae cytadhesin P1 gene with novel nucleotide sequence variation has been identified. Four clinical strains of M. pneumoniae were found to carry this type of P1 gene. This new P1 gene is similar to the known group II P1 genes but possesses novel sequence variation of approximately 300 bp in the RepMP2/3 region. The position of the new variable region is distant from the previously reported variable regions known to differ between group I and II P1 genes. Two sequences closely homologous to this new variable region were found within the repetitive sequences outside the P1 gene of the M. pneumoniae M129 genome. This suggests that the new P1 gene was generated by DNA recombination between repetitive sequences and the P1 gene locus. The finding of this new type of P1 gene supports the hypothesis that the repetitive sequences of the M. pneumoniae genome serve as a reservoir to generate antigenic variation of the cytadhesin P1 gene.

Adhesins, Bacterial↗
PubMed1997

Simple, rapid and sensitive method for the determination of indomethacin in plasma by high-performance liquid chromatography with ultraviolet detection.

A micro method for determination of indomethacin in plasma was developed. Following deproteinization of plasma with acetonitrile containing internal standard (mefenamic acid), the separation of indomethacin and internal standard was achieved by high-performance liquid chromatography using a 7 microm LiChrosorb-RP18 column (250x4 mm I.D.) at 50 degrees C. The mobile phase was 6 mM phosphoric acid-acetonitrile (50:50). The flow-rate was kept at 2.0 ml/min and the column effluent was monitored at 205 nm. The coefficients of variation of the method estimated at 0.2 and 1.0 microg/ml were 4.2 and 2.3%, and the detection limit of the drug was about 0.05 microg/ml (S/N=5). The method requires minimum pretreatment of the plasma with a small sample volume (25 microl), and is very suitable for therapeutic drug monitoring of indomethacin in premature infants with symptomatic patent ductus arteriosus.

Chromatography, High Pressure Liquid↗
PubMed1997

New carotenoids from the thermophilic green sulfur bacterium Chlorobium tepidum: 1',2'-dihydro-gamma-carotene, 1',2'-dihydrochlorobactene, and OH-chlorobactene glucoside ester, and the carotenoid composition of different strains.

The complete carotenoid composition of the thermophilic green sulfur bacterium Chlorobium tepidum strain TNO was determined by spectroscopic methods. Major carotenoids were four kinds of carotenes: gamma-carotene, chlorobactene, and their 1',2'-dihydro derivatives (1',2'-dihydro-gamma-carotene and 1',2'-dihydrochlorobactene). In lesser amounts, hydroxyl gamma-carotene, hydroxyl chlorobactene, and their glucoside fatty acid esters were found. The only esterified fatty acid present was laurate, and OH-chlorobactene glucoside laurate is a novel carotenoid. In other strains of C. tepidum, the same carotenoids were found, but the composition varied from strain to strain. The overall pigment composition in cells of strain TNO was 4 mol carotenoids and 40 mol bacteriochlorophyll c per mol bacteriochlorophyll a. The effects of nicotine on carotenoid biosynthesis in C. tepidum differed from those in the thermophilic green nonsulfur bacterium Chloroflexus aurantiacus.

Carotenoids↗
PubMed1997

Urinary excretion of mefenamic acid and its metabolites including their esterglucuronides in preterm infants undergoing mefenamic acid therapy.

Urinary excretion of mefenamic acid (MA) and its two oxidative metabolites, M-I (3'-hydroxymethyl derivative) and M-II (3'-carboxyl derivative), and their glucuronides was investigated in preterm infants undergoing MA therapy. MA was given orally at a dose of 2 mg/kg and the dose was repeated every 24 h a maximum of three times. Urine was collected for up to 5 d after the last dose, and MA and the metabolites were determined by a newly developed HPLC. The cumulative amounts of MA and the metabolites excreted in the urine varied from 7 to 46% of the total dose administered, and were less than those reported in adults and children. Significant correlation was observed between the plasma half-life of MA and the cumulative amount of MA and the metabolites excreted in the urine. These results suggest that long plasma half-lives of MA observed in preterm infants are due mainly to low activity of drug metabolizing enzyme(s). In an infant who received the two regimens of MA therapy about 2 weeks apart, the plasma half-life of MA was shortened and the urinary excretion of the MA metabolites including their glucuronides was greatly increased during this period. It is suggested that the activities of both cytochrome P-450(s) and glucuronyltransferase(s) related to MA metabolism rapidly increased during the first month of the infant's life.

Anti-Inflammatory Agents, Non-Steroidal↗
PubMed1994

Pharmacokinetics of mefenamic acid in preterm infants with patent ductus arteriosus.

The pharmacokinetics of mefenamic acid (MA), 2 mg/kg, were studied in 17 preterm infants with symptomatic patent ductus arteriosus. They were given this dosage orally at 24 h intervals. There were marked inter-individual differences in some of the pharmacokinetic parameters after the first dose; peak plasma concentration (Cmax) varied from 1.2 to 6.1 micrograms/mL with a mean of 3.8 micrograms/mL, time to reach Cmax (tmax) varied from 2 to 18 h with a mean of 7.7 h and plasma half-life (t1/2) varied from 3.8 to 43.6 h with a mean of 18.7 h. The group of infants (10/17) who had ductus closure after the first dose had significantly lower clearance (P < 0.01), longer t1/2 (P < 0.01) and higher 24 h plasma concentration (P < 0.001) compared to the group of infants (7/17) who had no ductus closure after the first dose. It appeared that the plasma concentration of MA had to be above 2.0 micrograms/mL and maintained at this concentration for at least 12 h for MA associated with ductus closure in preterm infants to take effect. In view of the inter-individual variation of plasma MA concentration and the effective plasma concentration, we suggest that measurement of the plasma concentration should be done 24 h after the first dose. This might be useful for safe and effective therapy for infants with ductus closure failure after the first dose.

Administration, Oral↗
PubMed1994

Effect of glycyrrhizin in children with liver dysfunction associated with cytomegalovirus infection.

Glycyrrhizin (GL) has an inhibitory effect on several viruses including human immunodeficiency virus type 1 (HIV-1) and varicella-zoster virus (VZV). In addition, some therapeutic and prophylactic effects on chronic active viral hepatitis have been claimed for GL. In this study, 0.2% GL dissolved in saline (2 mg/ml GL), supplemented with 2% glycine and 0.1% cysteine (Stronger Neo-Minophagen C, SNMC) was administered intravenously in a dose of 50 ml/day for a period of more than one week to three infants with cytomegalovirus (CMV) infection who exhibited abnormal liver function or hepatomegaly. Liver function had become normal at the end of the course of SNMC. These findings suggest that GL might have therapeutic effects on liver dysfunction associated with CMV infections.

Antibodies, Viral↗
PubMed1993

Influence of usual intake of dietary caffeine on single-dose kinetics of theophylline in healthy human subjects.

The influence of usual multiple ingestions of dietary caffeine on oral single-dose pharmacokinetics of theophylline has been investigated in 6 healthy male subjects. The subjects consumed 2 to 7 cups of regular instant coffee during the 24 h study period. Their mean serum concentrations of caffeine varied from 1.2 to 3.1 mg/l. After their usual intake of dietary caffeine, the serum concentrations of theophylline from 3 to 24 h after administration were significantly higher than after deprivation of dietary caffeine. The apparent elimination of theophylline half-life was prolonged from 6.3 (0.61) h (mean with (SEM)) to 8.3 (0.47) h (32% increase, P < 0.01) and the total body clearance was reduced from 55.0 (1.31) ml.h-1.kg-1 to 42.5 (2.63) ml.h-1.kg-1 (23% decrease, P < 0.001). Saturation of theophylline metabolism and/or competition between theophylline and caffeine metabolism in addition to theophylline derived from caffeine may be the cause of the delayed elimination of theophylline. The present study has indicated that a significant reduction in theophylline metabolism may be caused by a conventional intake of dietary caffeine. In bronchodilator therapy with theophylline, therefore, the daily consumption of caffeine should be taken into consideration.

Administration, Oral↗
PubMed1993

[Antimicrobial susceptibility patterns of the Proteeae in Japan, 1989].

We discussed the antimicrobial susceptibilities of Proteeae isolated in Japan, 1989. Eight hundred six clinical isolates were collected from 47 hospitals. These were comprised of 431 strains of Proteus mirabilis, 155 Proteus vulgaris, 154 Morganella morganii, 44 Providencia rettgeri and 22 Providencia stuartii. Antibiotics tested in this study were 2 penicillins, 5 cephems, 1 carbapenem and 2 aminoglycosides. The MIC's were determined using the standard method of the Japan Society of Chemotherapy. Susceptibilities of the above strains to these antibiotics are described below; 1. Latamoxef, ceftizoxime and imipenem had excellent activities with no evident differences among the species of Proteeae. 2. Ampicillin and cefazolin were less active against Indol-positive Proteeae. 3. Piperacillin and cefmetazole were also strongly active drugs against P. mirabilis, P. vulgaris and P. stuartii, and cefotiam against P. mirabilis and P. stuartii. 4. Gentamicin and netilmicin showed excellent activities against M. morganii.

Anti-Bacterial Agents↗