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Biomedical subjects

Y Shimada

Publications and source records attributed to Y Shimada.

At least 685 records · Page 38Linked to original sources
PubMed1985

Acetylcholine receptors of human skeletal muscle: a species difference detected by snake neurotoxins.

The binding abilities of the nicotinic acetylcholine receptors (AChRs) of the skeletal muscles of man and other vertebrates to two typical curaremimetic toxins, erabutoxin b (Eb) and alpha-bungarotoxin (alpha-BT), were investigated. Fluorescent microscopy using rhodamine-labeled erabutoxin b (TMR-Eb) and FITC-labeled alpha-bungarotoxin (FITC-alpha-BT) revealed that AChRs of human and chimpanzee muscles were stained with FITC-alpha-BT, but not with TMR-Eb. In contrast, the AChRs of mouse muscle were stained with both fluorescent toxins. The stainings of human and chimpanzee AChRs with FITC-alpha-BT were inhibited by preincubation with unmodified alpha-BT, but not with either unmodified Eb or other short-chain neurotoxins. Binding experiments using 125I-labeled Eb ([125I]Eb) and 125I-labeled alpha-BT ([125I]alpha-BT) showed that the affinity of human AChRs for [125I]Eb was unusually low. Electrophysiological experiments showed that both acetylcholine potential and end-plate potential of human muscle were blocked by addition of alpha-BT, but not by Eb. On the contrary, acetylcholine potential of rat muscle was blocked by addition of Eb. All these results indicate that AChRs of human and chimpanzee muscles are different from those of other animals in having an exceptionally low affinity for Eb and other short-chain neurotoxins. The results suggest a heterogeneity among vertebrate AChRs concerning their reactivities to curaremimetic toxins.

Animals↗
PubMed1985

A mutant plasmid with increased stability of holding and polymerization in Saccharomyces cerevisiae.

A yeast mutant plasmid, pX, showing increased stability of holding in mitotic and meiotic cell division, was isolated from an unstable plasmid, YRp7, which consists of pBR322 and a 1.4 kilobase (kb) fragment of Saccharomyces cerevisiae carrying the TRP1 gene and the autonomously replicating sequence, ARS1. The pX plasmid exists as circular molecules in a series of polymeric forms from the monomer to the 20-mer or more, consisting, except for the monomer, of even numbers of unit molecules in tandem arrangement. The pX monomer consists solely of a yeast DNA fragment of 849 base pairs (bp) containing the TRP1 and ARS1 sequences derived from the 1.4 kb yeast fragment of YRp7. The copy number of pX was calculated to be 20 as monomer units per genome. The ARS1 region was delimited to 80 bp by this mutation and the region essential for the ARS function was discussed.

DNA Replication↗
PubMed1985

Immunochemical analysis of troponin T isoforms in adult, embryonic, regenerating, and denervated chicken fast skeletal muscles.

Using monoclonal antibodies (McAbs) which can distinguish between breast- and leg-type troponin T (TnT), we studied the spatial distribution of TnT isoforms in adult chicken fast skeletal muscles. The breast (pectoralis major) and leg (iliotibialis posterior) muscles were composed predominantly of homogeneous fibers containing breast- and leg-type TnT, respectively. The posterior latissimus dorsi muscle was composed of heterogeneous fibers of at least two types, namely breast and leg types. In developing and regenerating fast muscles, only leg-type TnT was expressed at early stages, and later breast-type TnT appeared either transiently or permanently. This led ultimately to several distinct adult fast muscle breast/leg TnT isoform profiles. Since both types of TnT were synthesized in embryonic and regenerating muscles with nerves intact as well as in regenerating muscles with nerves resected, the switching on of their expression during fast muscle development appears to be independent of nerves. However, its full development ("fine tuning" of the protein isoform distribution within the fast fiber types) and the maintenance of the adult state are presumed to be dependent on the nerves, since, although regenerating fibers in denervated muscles could exhibit the early and then the later embryonic stainabilities, they again returned to the early embryonic state; further, the denervation of adult muscles caused the replacement of TnT isoform from the adult to the early embryonic state.

Animals↗
PubMed1985

Heat-shock induction of radiation resistance in primordial germ cells of the fish Oryzias latipes.

The effects of heat on the radiosensitivity of primordial germ cells at the quiescent stage in the fish Oryzias latipes were studied. The results show: (1) heat preceding but not following irradiation induced radioresistance which was reflected by improved survival; (2) its magnitude was a function of the heating time before irradiation; (3) improved germ-cell survival did not change with time for up to at least 4 hours after heat treatment at 41 degrees C for 30 min; (4) this resistance was more prominently expressed in the subsequent course of proliferation of female germ cells than in the non-proliferating male germ cells. In conclusion, heat induced radiation resistance in primordial germ cells of the female at the quiescent stage; this probably allows the cells subsequently to escape reproductive death.

Animals↗
PubMed1985

Influence of thermal conditioning on the heat-induced radioresistance in primordial germ cells of the fish Oryzias latipes.

Heat treatment (41 degrees C, 30 min) given before gamma-irradiation results in an increase in radiation resistance of primordial germ cells (PGCs) in Oryzias latipes at a mitotically inactive stage. This may be attributed to the appearance of a shoulder region on the dose-response curve, indicating an increased capacity to tolerate radiation damage. The radiation response curve is biphasic and the conversion of a radiosensitive population to a less sensitive one as a result of heat treatment is suggested. When the PGCs were made thermotolerant by a 'priming' heat treatment (41 degrees C, 10 min) a second heat treatment (41 degrees C, 30 min) at 2 h interval did not induce resistance to radiation. A treatment of 41 degrees C for 30 min without 'priming' gave a thermal reduction ratio of 4.6, whereas with 'priming' the ratio was 1.0. Thus heat induces radiation resistance in PGCs but this induction is suppressed under thermotolerant conditions.

Animals↗
PubMed1985

Effect of heat on radiosensitivity at different developmental stages of embryos of the fish Oryzias latipes.

Embryos of the fish, Oryzias latipes, at various developmental stages were heated before or after gamma-irradiation. The lethal effects of heat and radiation treatments were determined by the hatchability of the irradiated embryos. The radiosensitivity suddenly decreased at 3-days after fertilization. Heat (41 degrees C), either preceding or following irradiation, decreased the shoulder region (Dq) of the dose-response curves of the embryos irradiated at the 1-3 day stages, and increased the slope (D0) only at the 3 day stage. The magnitude of enhancement of radiosensitivity by pre- and post-heating was found to depend on the time and temperature of the heat as well as the developmental stage of the embryos; in 1- and 2-day embryos the effectiveness of post-irradiation heating was larger than that of pre-irradiation heating whereas in 3-day embryos there was no difference between the effectiveness of pre- and post-treatment. The sequence of heat (41 degrees C) and radiation treatment, and the time interval between the two treatments, also influenced the effectiveness of heat on radiosensitivity, depending upon the developmental stage; recovery from heat effects was not observed within a time interval of up to 3 h before radiation exposure for either 1- or 3-day embryos, whereas recovery from the radiation lesion occurred, for only 1-day embryos, within 1 h of subsequent heat exposure.

Age Factors↗
PubMed1985

Effects of driving pressure and respiratory rate on airway pressure and PaCO2 in rabbits during high-frequency jet ventilation.

The effects of driving pressure (DP) and respiratory rate (RR) on mean airway pressure (Paw), PaCO2, and other respiratory variables were studied during high-frequency jet ventilation (HFJV) in anesthetized rabbits. The animals were tracheotomized and paralyzed, and various combinations of RR (4, 8, 12, and 16 Hz) and DP (0.5, 1.0, and 2.0 kg/cm2) were applied randomly with an inspiratory/expiratory ratio of 1.0. HFJV was delivered via a 2.5-Fr catheter through a T-attachment, using 100% oxygen, and a hot-wire flowmeter was connected to the outlet of the T-attachment for measurement of the minute volume (MV). Heart rate, arterial BP and CVP, respiratory variables, and arterial blood gases were monitored during the study. There were no direct correlations between PaCO2 and DP, MV, or RR. However, there was an inverse correlation between PaCO2 and tidal volume, and linear correlations were found between Paw and DP, and between DP and MV. It is concluded that HFJV over an RR range of 4 to 16 Hz depends mainly upon tidal volume. When the desired PaCO2 and Paw are determined, DP and RR can be calculated following the equations established in this study.

Animals↗
PubMed1985

Elimination of false-positive limulus amebocyte lysate tests in patients with hyperlipidemia.

Varying concentrations of lipopolysaccharide (LPS) and mannan suspensions were mixed with either saline or plasma from normal volunteers, heated to 100 degrees C for 10 min, and then subjected to the limulus amebocyte lysate test (LAL). A positive LAL in saline required minimum LPS and mannan concentrations of 10(-11) and 10(-5) g/ml, respectively, while the minimum concentrations premixed with plasma were 10(-13) and 10(-9) g/ml, respectively. Thus, use of plasma instead of saline increased assay sensitivity 100-fold for LPS and 10,000-fold for mannan. In the second part of the experiment, normal plasma was separated into lipid and nonlipid phases by Folch's method. LAL analysis of each phase revealed equal sensitivity for LPS and mannan in the nonlipid phase, but no sensitivity in the lipid extract. Subsequently, 200 ml of a fat emulsion (Intralipos) was administered to the normal volunteers, and LAL and lipid analyses were performed. The LAL turned positive in all volunteers. When LAL was positive, triglycerides (TG), chylomicron (Chyl), and very low-density lipoprotein (VLDL) increased significantly compared with when LAL was negative. It is concluded that plasma lipids increase the sensitivity of LAL and directly activate LAL when TG, Chyl, and VLDL concentrations are high. This effect of plasma lipids on LAL can be eliminated by extracting LPS and mannan in the nonlipid phase.

Escherichia coli↗
PubMed1985

Effects of breathing therapy with a dead-space-resistance device on post-cardiac surgical patients.

The effects of a dead-space-resistance device (IDSEP breather) on Pao2, Paco2 and functional residual capacity (FRC) in 11 post-cardiac surgical patients were studied. There were no significant changes in Pao2, Paco2 and FRC after the IDSEP therapy. Changes in Pao2 between the pre- and post-IDSEP therapy correlated well with changes in FRC (r = 0.797, P less than 0.01). Breathing therapy with the dead-space-resistance device appeared not to bring any benefit in early post-cardiac surgical patients.

Adult↗
PubMed1985

Pleural stress pressure as a force to control liquid accumulation and maintain lung expansion.

Total gas pressure in the pleural space is more subatmospheric than that in the alveolar cavity. This pressure difference minus elastic recoil pressure of the lung was termed stress pressure. We investigated the relationship between stress pressure and a force that would hold the lung against the chest wall to prevent accumulation of liquid. The condition was a pleural space with an enlarged pleural surface pressure. Dogs anesthetized with pentobarbital sodium were placed in a box maintained subatmospherically at approximately -30 cmH2O and breathed atmospheric air for 4 h. Liquid volume in the pleural space of the dogs was measured under conditions of thoracotomy. In the normal group, the volume of the pleural liquid was within the normal range of approximately 2.0 ml and the visceral and the parietal pleura made contact. In the pneumothorax group, established by injecting 50 ml of air into the pleural space, the liquid increased significantly in all cases by a mean value of approximately 12 ml. Thus pleural stress pressure seems to be an important force holding the lung against the chest wall and aiding in the control of accumulation of liquid in a more subatmospheric pleural space.

Animals↗
PubMed1985

[A developmental study about the effect of an organizational strategy on memory in mental retardates].

The purpose of this study was to investigate the organizational strategy of memory in mental retardates. Forty young (mean CA = 9:07, mean IQ = 60) and forty old retardates (mean CA = 13:07, mean IQ = 58) were required to learn a list of sixteen pictures from four taxonomic categories. Learning was continued during four trials by study-test method. In B-C treatment subjects were presented the pictures in category block and required to recall in constrained method with category. In R-F treatment subjects were presented pictures in random order and asked free recall. The effect of an organizational strategy on recall prompted by B-C treatment was found to be greater in the old retardates than in the young retardates. Thus the memory strategy of retardates showed the same developmental order with time lag as in normal children, and the developmental lag theory (Zigler, 1969) was supported.

Adolescent↗
PubMed1985

[Fundamental and clinical studies of cefminox in children].

Cefminox (CMNX, MT-141), a newly developed injectable cephem antibiotic, was administered intravenously as one shot injection at 3 different dosages of 10, 20 and 40 mg/kg to 9 children; for each dose level 3 children were used. In these children serum and urinary concentrations as well as recovery rates were determined. In addition, in order to determine clinical and bacteriological efficacies of CMNX, it was used in the treatment of 37 cases of various infections consisting of 2 cases of acute tonsillitis, 1 case of acute tonsillitis associated with otitis media, 1 case of acute bronchitis, 1 case of chronic bronchitis, 20 cases of pneumonia, 1 case of pneumonia associated with otitis media, 8 cases of urinary tract infections, 2 cases of purulent lymphadenitis and 1 case of gluteal abscess. The drug was administered intravenously as one shot injection at a mean daily dosage of 76.6 mg/kg, in 4 divided doses in most cases, for a mean period of 6 days. Finally, in 43 cases added of 6 drop out cases which were included in analysis of efficacy side effects and abnormal laboratory findings were examined. The following results were obtained. In 9 cases, which received CMNX at 3 different dosages of 10, 20 and 40 mg/kg for 3 cases each intravenously as one shot injection, mean serum concentrations reached the peaks of 109.4, 218.1 and 357.1 mcg/ml at 5 minutes after injection, respectively, showing dose response relation. The mean half-lives were 1.74, 1.62 and 1.84 hours, respectively. The mean concentrations of CMNX in urine in the same cases as used for determinations of serum concentrations were highest during the 0 approximately 2 hours period, reaching 1,582, 3,304 and 4,618 mcg/ml at the respective doses. The mean recoveries within the first 6 hours were 82.8, 69.8 and 81.3%, the rate for 20 mg/kg group being lower than those obtained for the other groups. This is possibly due to 1 case which showed unusually low recovery rate of 44.4%. When this case is excluded, the recovery rates became similar for all groups. As to clinical results, responses rated as good or higher were obtained for 91.9% of the cases (34 cases/37 cases), with high efficacy rate. No side effects were seen in 43 cases included of drop out cases.(ABSTRACT TRUNCATED AT 400 WORDS)

Adolescent↗
PubMed1985

[Effect of BRL 25000 (clavulanic acid-amoxicillin) on bacterial flora in human feces].

BRL 25000 (187.5 and 375 mg tablets), a formulation of CVA-K and AMPC in the ratio of 1:2, and AMPC (as control drug) were administered to healthy volunteers, aged 20 approximately 28 years and weighing 60 approximately 85 kg (68.8 kg, on average). Each drug was administered 3 times a day (after meals) for 5 days and the volunteers were separated into 3 groups of 4 subjects each. The effect on the fecal flora was studied before dosage, during administration (day 3 and 5) and day 3 and 5 after the administration course was completed. Studies were undertaken to isolate C. difficile on the last day of administration and 3 and 5 days after administration had ceased. Fecal concentrations and the susceptibility of the isolates to AMPC, CVA-K and BRL 25000 were measured. Side effects and laboratory findings were studied. The results obtained were as follows: 1. In BRL 25000 (187.5 mg X 3/day) group, the population of E. coli was on average, 1 X 10(6) approximately 9 X 10(6) cells/g feces before initiation of administration and it increased by 2 logarithms 3 and 5 days after initiation of administration. By 3 and 5 days after end of administration, the E. coli population was similar to the initial population. The population of Klebsiella sp. was 1 X 10(6) approximately 9 X 10(6) cells/g feces on average before commencement of dosage and it increased by 2 logarithms 3 days after initiation of administration but there was no consistent change in the Klebsiella sp. population thereafter. The Enterobacter sp., population was not consistent neither was the population of other Enterobacteriaceae. In total, the mean Enterobacteriaceae population was 1 X 10(7) approximately 9 X 10(7) cells/g feces before initiation of administration and increased by 2 logarithms 3 days after initiation of administration, and then returned to the initial level 5 days after end of administration. No consistent changes in population were noted for the other Gram-negative bacilli. The Staphylococcus sp. population was 1 X 10(6) approximately 9 X 10(6) cells/g feces on average before initiation of administration. This organism was detected in only 1 case 3 days after initiation of administration and in another 5 days after initiation of administration, thereafter, the population was similar to the initial population.(ABSTRACT TRUNCATED AT 400 WORDS)

Administration, Oral↗
PubMed1985

[Effects of KS-R1 (ampicillin suppository) and ampicillin oral dosing on fecal flora of children].

A newly developed product, KS-R1 (a suppository containing 250 mg potency of ampicillin (ABPC)), was given to 7 children (5 boys and 2 girls) ranging from 4 years and 5 months to 8 years and 10 months in age, 3 times a day (average daily dose, 62.4 mg/kg) for 5 days. As a control, the same amount of ABPC dry syrup was given orally to 7 children (4 boys and 3 girls) ranging from 2 years and 8 months to 7 years and 7 months in age, 3 times a day (average daily dose, 55.3 mg/kg) for 5 days. The effects of these 2 preparations on the bacterial flora of the feces were investigated, and concentrations of ABPC in the feces and sensitivities of the isolated strains to ABPC were determined. The results were as follows. As for Gram-negative bacilli in the feces from children given KS-R1, there was no change in Escherichia coli, Klebsiella sp., Citrobacter sp. and Enterobacter sp. which were isolated from many children 3 days after the end of treatment, but they did not show any constant pattern of change in mean number. Other species did not show any pattern of increase in the number of children from whom they were isolated, or in the number of bacteria during the course after the beginning of treatment. The total number of bacteria identified as Enterobacteriaceae was at the level of 10(8) cells/g on any day of examination. Of Gram-negative bacilli other than Enterobacteriaceae, Pseudomonas sp. showed no constant pattern of change in number. On the other hand, of Gram-positive bacteria, there was no constant pattern of change in the number of Staphylococcus aureus, Coagulase-negative Staphylococci began to be isolated from many children 5 days after the beginning of treatment and were isolated from all children 5 days after the end of treatment, but there was no tendency for the mean number to increase. Enterococcus sp. was not isolated from 3 children 3 days after the beginning of treatment, and was decreased in number by one order in 3 out of other 4 children as compared with before-treatment. However, this species was isolated from all children 3 days after the end of treatment, and the mean number of bacteria was similar to that before-treatment although the number of bacteria was different in individual children.(ABSTRACT TRUNCATED AT 400 WORDS)

Administration, Oral↗
PubMed1985

[Fundamental and clinical studies on ceftizoxime suppositories in children].

The peak levels of serum ceftizoxime (CZX) after a single rectal administration of CZX-S at doses of 125 and 250 mg in 157 pediatric patients were occurred at 21 approximately 25 minutes in pediatric patients aged less than 1 year and over than 7 years, at 16-20 minutes in 1-3 years patients, at more than 26 minutes in 4-6 years patients. They were 9.45, 9.58, 11.71, 12.43 mcg/ml, respectively. The mean highest levels of serum CZX were 8.56, 10.66, 12.50 mcg/ml after the administration of CZX-S as less than 10.0, 10.1-15.0, 15.1-20.0 mg/kg dose respectively, all of which were occurred at 21-25 25 minutes. A close dose response was observed. The pain of insertion was not observed in any cases. The discharge of melted suppository or defecation after administration was observed in 15.2% of total 184 cases, which was noticed more frequently in the lower aged children. There was no influence by dose. Clinical effects of CZX-S were studied in 72 pediatric patients with various infections. CZX-S was administered rectally at the mean daily dose of 41.0 mg/kg divided into 3 or 4 times for 6 days. Clinical responses were excellent in 46 cases, good in 24 cases, fair in 2 cases. The efficacy rate was 97.2%. Regarding side effects, the pain of insertion was noted in 2 cases (2.8%), diarrhea in 6 cases (8.3%), the elevation of eosinophil in 1 case (1.7%). Bacteriologically, 23 strains (92.0%) out of 25 strains isolated from the patients were eradicated.

Bacteria↗