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Biomedical subjects

T Imoto

Publications and source records attributed to T Imoto.

At least 181 records · Page 10Linked to original sources

[Menière's disease and isosorbide as an oral hyperosmotic agent (author's transl)].

According to a nationwide survey in 1977 and average of 54.7% of Menière's disease patients were unable to function normally in their daily lives. These patients mostly complained of repeated attacks of vertigo (male 40.3%, female 29.2%) (Watanabe et al. 1980). For the purpose of improving the repeated attacks of vertigo, Isosorbide as an oral hyperosmotic diuretic was first administered orally to 21 patients with Menière's disease from November 1979 to January 1981 for reducing the endolymphatic hydrops that can be presumed to be of pathogenetic importance. The electrocochleographic examinations were carried out on these patients at the same time. Usually, the SP/AP wave form in the electrocochleographic examinations appears to be more abnormal in patients with a fluctuating hearing loss or a flat hearing loss. The average of negative SP/AP in 24 patients with Meniére's disease was 0.54. The indication of Isosorbide administration was determined by this particular SP/AP wave abnormality, and clinical of Isosorbide for the patients with Menière's disease were evaluated. In 18 patients who experienced relief, attack of vertigo did not occur in 12 (63%) and vertigo was relieved in six (31%). In two patients with long administration, hearing improvement could already be observed during the period of treatment. The electrocochleographic examinations showed a decrease in the SP/AP wave form. In two patients with short administration, hearing loss was temporarily observed in middle and low frequencies; the hearing loss later improved more than before treatment in these patients. In only one patient, aggravation of hearing was observed after administration, but whether it was a side effect or not, remains to be understood. The period of observation of these results was a mean value of 4 months and 12 days. The Isosorbide therapy in patients with Menière's disease in expected to replace saccus surgery.

Adult↗

67Ga scanning and upper gastrointestinal series for gastric lymphomas.

67Ga scanning and upper gastrointestinal (UGI) series were performed in 13 patients with gastric lymphomas before any treatment was initiated. Seven of these patients also underwent both examinations after completing chemotherapy and/or radiation therapy. Prior to treatment, all 13 patients had abnormalities on the UGI examination, and 12 of them had abnormalities on the 67Ga scans. In 6 patients, more extensive gastric abnormalities were demonstrated by 67Ga scanning than by UGI examination. Although persistent 67Ga uptake after treatment was indicative of relatively poor therapeutic response, lack of uptake did not always indicate a good response to treatment.

Aged↗

The correlation between the vestibulo-ocular system and the vestibulo-spinal system in Ménière's disease based on categorical principal component analysis.

Correlations among different equilibrium function tests were investigated in 130 patients with Ménière disease. The tests consisted of 22 different items, and the possible results could be put into a total of 49 categories. Using a factor analytic method, results falling in the positive area of the 1st axis indicate normality of the vestibular system, and results in the negative area, indicate an abnormality of the vestibular system. On the 2nd axis, the negative direction indicates an abnormality of the vestibulo-spinal system, and the positive direction an abnormality of the vestibulo-ocular system. In this paper, relationships among sex, age, the Cornell medical index results, and the time between the vertigo attack and testing, as well as between the onset of the disease and testing, are shown on a two-dimensional plane.

Adolescent↗

Selective modification of aspartic acid-101 in lysozyme by carbodiimide reaction.

A general procedure which selectively introduced a nucleophilic group at a particular location in the active site of lysozyme has been developed. The coupling of hen egg white lysozyme with amine nucleophiles by 1-ethyl-3-[3-(dimethylamino)propyl]carbodiimide hydrochloride (EDC) was studied at pH 5 and room temperature. In the presence of an amine nucleophile, such as ethanolamine, ethylenediamine, methylamine, or 4(5)-(aminomethyl)imidazole, the carboxyl side chain of aspartic acid-101 in lysozyme was selectively modified by using a small excess of EDC. The reactivity of Asp-101 is probably due to the specific binding of EDC to the substrate binding site close to Asp-101. With histamine or D-glucosamine, the selectively of Asp-101 was somewhat decreased. This may be due to the specific binding of these amines to lysozyme in competition with EDC, causing a decrease of the selective activation of Asp-101 by EDC. Depending on the amine employed, the lysozyme derivatives obtained exhibited decreased activity (83-52% of native enzyme), suggesting that the modification of Asp-101 weakened substrate binding.

Amino Acids↗

Binding of calcium to lysozyme and its derivatives.

Bindings of calcium to lysozyme and its derivatives were studied by UV difference spectroscopy at various pH's. The binding constant was ca. 40 m-1 at around neutral pH. The binding caused proton release from lysozyme and did not inhibit the binding of tri-N-acetylglucosamine to lysozyme. In the presence of 0.2 M Ca2+, lysozyme showed 26% of the activity of the free enzyme toward hexa-N-acetylglucosamine but the cleavage pattern was similar to that of the free enzyme. Thus, calcium was predicted to bind near the catalytic carboxyls to cause inhibition of lysozyme activity. It was found from the results of protease digestion that calcium binding shifted the native-denatured transition in lysozyme toward the native state.

Acetylglucosamine↗

Lysozyme-catalyzed reaction of chitooligosaccharides.

The time-courses of substrate consumption and product formation in the lysozyme-catalyzed reaction were determined with (GlcNAc)4 and (GlcNAc)5 as substrate to accumulate data suitable for the estimation of rate constants by numerical analysis. The lysozyme-catalyzed reactions were followed by TLC or HPLC. (GlcNAc)4 decomposed apparently to small oligosaccharides within 5 h, and (GlcNAc)5 decomposed within 15 min at pH 5.0 and 50 degrees C. The temperature-dependence of the rate of disappearance of the initial substrate showed a different profile from that observed with glycol chitin as substrate by the reducing power method. The order (or distribution) of the amount of product formed from (GlcNAc)5 in the reaction time-course determined by TLC differed from that determined by HPLC. The relative error in HPLC was much less than that in TLC, and the time-course determined by HPLC was thought to be of sufficient accuracy for the estimation of rate constants by computer analysis.

Acetylglucosamine↗

Estimation of rate constants in lysozyme-catalyzed reaction of chitooligosaccharides.

The rate constants of the cleavage of glycoside linkage, hydration (hydrolysis) and transglycosylation in a lysozyme-catalyzed reaction of substrate chitooligosaccharides were evaluated by computer analysis of the experimentally obtained reaction time-courses. In the computer analysis, the rate equation was numerically solved by use of the known binding constants for each subsite. Because of the complexity of the lysozyme-catalyzed reaction, optimal values of rate constants were determined by checking the sensitivity of each rate constant to the computed time-courses. It was not possible to estimate uniquely the rate constants for transglycosylation and hydration, owing to the nature of the enzymatic reaction, but it was possible to estimate accurately their ratio. The estimated values were 0.94 s-1 for the rate constant for the cleavage of glycosidic linkage and 133 for the ratio of rate constants of transglycosylation and hydration.

Acetylglucosamine↗

Identification of residue 103 in hen egg-white lysozyme.

Since it has been uncertain whether residue 103 in hen egg-white lysozyme is aspartic acid or asparagine, we reexamined the identity of this residue. To avoid complication, the tryptic peptide T-13 (Ile 98-Arg 112) was further cleaved. The peptide containing residues Gly 102-Arg 112 was obtained by tryptic digestion of lysozyme modified at Asp 101 with diethylenetriamine. The peptide containing residues Ile 98-homoserine 105 was obtained by BrCN treatment of peptide T-13. Both Edman degradation of the former peptide and carboxypeptidase X digestion of the latter peptide identified residue 103 in hen egg-white lysozyme as asparagine.

Amino Acid Sequence↗

[Pharmacokinetics of cephaloridine (author's transl)].

I studied on absorption and excretion of cephaloridine. Cephaloridine was administered intravenously to 5 healthy volunteers weighing 65 kg to 83 kg, and the blood levels were measured. A cross over test subjecting 2 grams intravenous drip infused for 1 hour against the same dose for 2 hours were performed after 1 week interval. The disposition of cephaloridine was estimated by applying one-compartment model which was scaled from YOKOKAWA & HULET PACKARD'S disc top computer. Pharmacokinetic parameters are as followings: 1 hour d.i.v.: Kel 1.410 (hr-1), Vd 9.629(L), T 1/2 30.290 (min.) 2 hours d.i.v.: Kel 0.876 (hr-1), Vd 21.106(L), T 1/2 49.372 (min.).

Adult↗

The dynamics of clindamycin-2-phosphate in vivo and its transfer to tissues.

Studies were conducted on clindamycin-2-phosphate, a preparation of clindamycin CLDM developed for injection, and the following results were obtained. 1) The concentration of CLDM phosphate and lincomycin (LCM) in sera were measured in rabbits following continuous intravenous infusion of 20 mg/kg over a 60 minute period, and the results were compared in a crossover test. 2) The concentration of CLDM phosphate in the oral tissues of rabbits following continuous intravenous drip infusion of 20 mg/kg over a 60 minute period was found to be a maximum in the submaxillary gland (21.1 microgram/g), followed by the liver, submaxillary lymph nodes, sera and tongue. The concentration of LCM was found to be the highest in the submaxillary gland (20.2 microgram/g), followed by the submaxillary lymph nodes, tongue, sera and liver. 3) The metabolism of CLDM phosphate in vivo was investigated using TCL. CLDM phosphate was found to metabolize to CLDM N-demethyl CLDM in vivo. 4) The peak concentration of CLDM phosphate in human sera following intravenous drip infusion of 600 mg over a 60 minute period averaged 11.9 microgram/ml, while the average concentration of LCM in sera under identical circumstances was approximately twice that of CLDM phosphate.

Animals↗

[The comparison of blood levels between peripheral vein and tooth extraction wound after the oral administration of antibiotics (author's transl)].

The oral administration of 300 mg of clindamycin was undertaken on 23 patients, of 500 mg of cefadroxil on 11 patients and of 250 mg of talampicillin on 12 patients, and then tooth extraction was performed under local anesthesia. Blood samples were taken from the extraction wound and the peripheral vein at the same time and assayed by the bioassay method. The blood levels of clindamycin and cefadroxil indicated a similar pattern between the extraction wound and the peripheral vein, but the blood level of talampicillin reached peek level rapider than clindamycin and cefadroxil. The blood levels of the extraction wound were 60 - 80% as compared with the venous blood levels with each antimicrobial agent.

Administration, Oral↗