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Biomedical subjects

S Iwata

Publications and source records attributed to S Iwata.

At least 235 records · Page 13Linked to original sources
PubMed1992

Intranasal aerodynamic aspects in patients with nasal septal perforations.

In an attempt to determine the influence of septal perforations on nasal airflow, nasal resistances were measured with active posterior rhinomanometry and compared before and after closure of asymptomatic septal perforations in five patients. No significant differences were found in the nasal resistances before and after closure of perforations either on inspiration or expiration. All patients were also unaware of any perceptive changes in nasal patencies after closure of the perforations.

Aged↗
PubMed1992

A device for tracheal tube during CO2 laser irradiation in laryngomicrosurgery.

We devised that the segment of commercially available defensor II tube coming in contact with the vocal cord was concaved. We used this new tube during CO(2) laser irradiation in laryngomicrosurgery. We came to the conclusion that it was much more superior to the conventional tube in safety and resistance of the material to Co(2) laser irradiation and in increase of the operation field.

Journal Article↗
PubMed1992

Impaired energy metabolism of lymphocytes in cirrhotics after hepatectomy.

To clarify the mechanism of high susceptibility to infection in cirrhotics, the changes in adenylate energy charge and MTT assay in peripheral blood lymphocytes were studied in cirrhotic and noncirrhotic patients in the early postoperative period after hepatectomy. The adenylate energy charge measured by radioactive labeling of the lymphocyte adenine nucleotide pool showed no significant difference preoperatively between cirrhotics and noncirrhotics, but a significant difference was observed in the pre- and postoperative distribution of adenine nucleotide metabolites (P less than 0.01). In the cirrhotic group, the adenylate energy charge of lymphocytes decreased significantly to 0.807 +/- 0.011 on the third postoperative day compared with preoperative value (0.891 +/- 0.006, P less than 0.01) and was restored to the normal range on the fifth and tenth postoperative days (0.886 +/- 0.006, 0.899 +/- 0.014), while no significant decrease was observed in the noncirrhotic group. MTT assay revealed that lymphocyte cell function decreased significantly in cirrhotics after hepatectomy. These results indicate that, in cirrhotic patients, the energy metabolism of lymphocytes is already impaired to some extent preoperatively, and that it undergoes further deterioration when surgical stress is applied. It is suggested that the decreased energy metabolism in the lymphocyte may be responsible for the increased susceptibility to infection in postoperative cirrhotics.

Adenosine Diphosphate↗
PubMed1992

Upregulation of postsynaptic dopamine receptors in the striatum does not influence haloperidol-induced catalepsy in mice.

The incidence of haloperidol-induced catalepsy was investigated in mice whose postsynaptic dopamine (DA) receptors in the striatum had been upregulated by denervation with 6-hydroxydopamine (6-OHDA). In nonupregulated mice, which were injected with 6-OHDA 4 days before, DA in the striatum fell to 21% of the level found in vehicle-injected mice but [3H]spiperone binding to the membrane of the striatum did not increase. In upregulated mice, which were injected with 6-OHDA 28 days before, DA was at 24% and [3H]spiperone binding increased by 15%. The ED50 values (with 95% confidence limits) for haloperidol-induced catalepsy in nonupregulated mice and that in upregulated mice was 0.40 mg/kg (0.25-0.65 mg/kg) and 0.29 mg/kg (0.16-0.51 mg/kg), respectively. There was no significant difference in the incidence of catalepsy between the two groups of mice. This suggests that the intensity of catalepsy produced by the DA receptor blockade may be unaltered even when the density of receptors increases.

Animals↗
PubMed1992

Changes in the redox distribution of rat liver by ischemia.

The changes in the redox distribution of the ischemic rat liver were studied using the redox scanner, which is a time-sharing, tissue fluorescence and reflectance spectroscopy with fine spatial resolution, with the results presented as a histogram and a gray-scaled picture. Hepatic inflow was clamped for 10 min (group 1), 20 min (group 2), and 30 min (group 3). The ratio of oxidized flavoprotein to reduced pyridine nucleotide fluorescence (FP/PN), representing the intracellular redox state, and hemoglobin reflectance were measured prior to clamping and at subsequent times following declamping in each group. The mean and the range width of FP/PN histogram decreased with the prolongation of ischemic time. In group 1, FP/PN histogram showed a remarkably wide range at 2 min after declamping but was almost completely recovered to preischemic levels at 10 min after declamping. In contrast, in groups 2 and 3, the mean of FP/PN histogram was only partially recovered at 10 min after declamping and the range width continued to increase. The correlation between FP/PN fluorescence and hemoglobin reflectance pictures suggested that the local stagnation of blood flow caused tissue hypoxia, preventing the recovery of the redox state probably in the centrilobular area.

Alanine Transaminase↗
PubMed1992

Mechanism of allosteric transition of bacterial L-lactate dehydrogenase.

The allosteric behaviour of L-lactate dehydrogenase (L-lactate:NAD+oxidoreductase, EC 1.1.1.27, LDH) from Bifidobacterium longum aM101-2 was studied by means of the subunit hybridization technique as well as X-ray crystallography. Homotropic allosteric response of the LDH activity was found against the concentration of its substrate, pyruvate. Heterotropic allosteric activation of the enzyme was induced by the addition of fructose 1,6-bisphosphate (FBP). Two mutant enzymes, which had either altered sensitivity to FBP or altered substrate specificity from pyruvate to oxaloacetate, were made by site-directed mutagenesis. Hybrid LDHs, between the wild and the mutant LDHs, were made by in vivo subunit hybridization using double transformation of Escherichia coli with two plasmids carrying either the gene of wild or mutant LDH. Introduction of only one desensitized mutant subunit to the LDH changed the characteristic of the wild enzyme to that of the mutant LDH. Kinetic studies on hybrid enzymes consisting of subunits having different substrate specificity indicated that there was a strong cooperative interaction among subunits. These results strongly support the idea that the allosteric change of the LDH fits the concerted-symmetry model proposed by Monod, Wyman, and Changeux. We analysed the crystallographic structure of the LDH having low affinity to substrate at 1.9 A resolution. By the comparison of the structure with that of other LDHs, we concluded that the conformational transition of the LDH was mainly caused by concerted rotations of subunits.

Allosteric Regulation↗
PubMed1992

Thyroid storm associated with probable subclinical hypoadrenocorticism in an elderly woman.

A 73-year-old woman was admitted to the hospital for severe persistent vomiting with fever, drowsiness, and weight loss. Elevated serum levels of thyroid hormones and the presence of a consciousness disorder with fever and vomiting led to the diagnosis of thyroid storm. A low normal concentration of serum cortisol, urinary 17-hydroxycorticosteroids and an elevated plasma level of corticotropin suggest that an inadequate adrenal reserve have been involved in the pathogenesis of the thyroid storm in this patient. She responded to the administration of intravenous methimazole and oral supersaturated potassium iodide solution.

17-Hydroxycorticosteroids↗
PubMed1992

Effects of inline filtration on delivery of gentamicin at various flow rates.

The effects of inline filtration on delivery of gentamicin (GM) in the pediatric field were studied. The filter sets (Pall 0.20 micron. JMS 0.20 micron, and IVEX 2.022 micron) were studied using a simulated system. 10 mg of GM was injected into the system containing 5% dextrose in water (flow rate: 50 ml/hr, 10 ml/hr and 2 ml/hr) with horizontal and vertical settings of the inline filters. In case of 50 ml/hr, delivery of GM of Pall showed nearly the same delivery pattern as compared with no filter setting. However, JMS and IVEX 2 showed little differences. In case of 10 ml/hr and 2 ml/hr those differences became more significant. Delivery of GM was influenced by the priming volume of the filters, increasingly so at slow flow rates. Filter settings also influenced the delivery of GM. Furthermore, with regards to the results of the Vitamin K2 delivery and the technetium radiotracer method, JMS and IVEX 2 filters were observed to have some stagnation of drugs in the filter. Not only priming volumes of the filters affect delivery of drugs, filter designs also have an influence. The use of the inline filters is important in the pediatric field, but their charactaristics for drug delivery pattern should be considered.

Drug Contamination↗
PubMed1992

[Spontaneous cerebrospinal fluid otorrhea in a normal inner ear. A case report].

A 49-year-old male with spontaneous cerebrospinal fluid (CSF) otorrhea, an extremely rare condition, is presented as the third reported case in Japan. The patient visited us complaining of sudden hearing loss and fullness of the ear on the left side. A tegmen defect of the posterior cranial fossa and CSF leakage from the fistula into the mastoid air cells, but a normal inner ear, were found by means of metrizamide CT. The fistula was surgically occluded with fascia temporalis and an artificial bone with fibrin glue. The CSF otorrhea from the tegmen defect was successfully stopped by this procedure and no recurrence has been observed. We discuss this extremely rare disease in this paper.

Cerebrospinal Fluid Otorrhea↗
PubMed1992

Alterations in the proton ATPase activity of rat liver mitochondria after hemorrhagic shock.

To clarify the damage site of complicated oxidative phosphorylation function after hemorrhagic shock in jaundiced liver mitochondria, the proton adenosine triphosphatase complex (H(+)-ATPase) activity of inside-out submitochondrial particles, mitochondrial membrane potential, and oxygen consumption in the presence of uncoupler were studied as indices of phosphorylation, membrane intactness, and oxidation, respectively. Hemorrhagic shock was induced according to the Wiggers' model (mean arterial blood pressure = 40 mm Hg) in rats made jaundiced by common bile duct ligation; rats that had undergone sham operations served as controls. After reinfusion of the shed blood, all of the control rats survived, but all of the jaundiced rats died. Liver mitochondria from jaundiced rats after 1 hour of hypotension demonstrated a 48% decrease in mitochondrial ATPase activity without remarkable changes in either oxidative activity or membrane potential of liver mitochondria. The reduction of ATPase activity appeared to be due to its release in the supernatants obtained from submitochondrial particles, because the ATPase activity of supernatants in jaundiced rats was significantly (p less than 0.001) higher than that of the controls. It is suggested that this enzyme plays a key role in energy restoration in recovery from shock.

Animals↗
PubMed1992

[A case of leiomyoma of the chest wall].

A case report of a leiomyoma of the chest wall is presented. So far as we examined, this is the first case of the leiomyoma of the chest wall in Japan. A 40-year-old woman was admitted to our hospital because of an abnormal shadow in the right upper lung area in a chest X-ray film. The thoracic CT and MRI demonstrated a tumor of the chest wall projecting into the thoracic cavity. The tumor was excised. Histological examination indicated that the tumor was a benign leiomyoma. This tumor seems to originate from the wall of the small vessels histologically. The patient's postoperative course is uneventful.

Adult↗
PubMed1992

[Effect of meropenem on fecal flora in children].

Meropenem (MEPM, SM-7338), a novel parenteral carbapenem antibiotic, was examined for its effect on intestinal flora in children. Seven children with infectious diseases (3 male and 4 female children of age's ranging from 4 months to 8 years and 9 months weighing from 7.3 to 23.0 kg) were treated with MEPM at doses ranging 10.3 to 40.5 mg/kg 3 or 4 times a day for 6 to 12 days. Before, during and after the treatment, identities and numbers of various bacteria contained in 1 g of feces were determined and fecal beta-lactamase activity and Clostridium difficile D-1 antigen were also assayed. Changes in fecal flora during MEPM treatment was somewhat different depending on cases. Regarding Enterobacteriaceae among aerobes, all of 7 cases exhibited moderate or pronounced reductions in Escherichia coli. Some of the cases exhibited the tendency to increase in Klebsiella oxytoca. Enterobacter cloacae and Citrobacter freundii. E. coli which was reduced during the treatment increased rapidly after the treatment in 5 out of 7 cases, and the initial bacterial counts were restored. Diverse strains were observed within the genus Enterococcus, while the overall bacterial counts of this genus exhibited the tendency to increase during the treatment. As a result, no significant change in total aerobe count was observed in any case except 1 case where Enterococcus count was somewhat reduced. Among anaerobes, major bacteria such as Bacteroides, Bifidobacterium, Eubacterium and Peptococcaceae exhibited tendencies to decrease in some cases during the antibiotic treatment. Two infants and 1 child exhibited significant decreases in total anaerobe counts. In most of the cases, such changes in major anaerobes were transient and bacterial counts recovered to their initial values rapidly after completion of the treatment. In no cases, glucose non-fermentative Gram-negative bacilli or fungus became predominant. Although C. difficile D-1 antigen was observed in 4 cases, its changes had no relationship with characteristics of feces. C. difficile was not detected in any of the cases. MEPM was detected in feces in 4 cases being treatment, in concentrations ranging from 0.35 to 66.0 micrograms/g. Fecal MEPM levels were very low except in 1 case in which beta-lactamase was negative. From these results, effects of MEPM on intestinal flora in children were relatively minor compared to other new beta-lactam drugs. However, a care should be taken to minimize diarrhea and bacterial turnover when a prolonged use of the antibiotic, was practiced because of potential significant effects on intestinal flora.

Age Factors↗
PubMed1992

[The influence of cefprozil on intestinal bacterial flora].

Cefprozil (CFPZ, BMY-28100), a new oral cephalosporin antibiotic, was studied for its effect on the intestinal bacterial flora in pediatric patients. The subjects were children admitted for infections (2 males and 2 females, 9 months to 6 years 3 months old, weighed 4.3 to 19.0 kg). CFPZ granule was orally administered at a dose between 10.0 to 11.6 mg/kg, 3 doses daily, over 4 to 14 days. The feces from these children were collected before, during and after administration, and bacteria were identified and counted. CFPZ concentration, beta-lactamase activity were also assayed. Bacterial flora in feces during CFPZ administration showed some variance, but no significant change was observed in main aerobes and anaerobes. And in no case, glucose nonfermentative Gram-negative bacilli or fungi were found dominant. beta-Lactamase activity was positive in the feces in all cases. CFPZ concentrations were not detectable in feces before, during and after administration. The above results suggest that CFPZ is a drug with little influence on the intestinal bacterial flora in children.

Administration, Oral↗
PubMed1992

[Laboratory and clinical studies on cefprozil granules in pediatrics].

Fundamental and clinical effects of cefprozil (CFPZ, BMY-28100) granules, a new oral cephalosporin antibiotic, in pediatric field were investigated. The result obtained were summarized as follows. 1. CFPZ (10% granules) was given to 1 child in a single dose of 7.5 mg/kg. The peak serum concentration of CFPZ was 4.51 micrograms/ml at 2 hours after administration. Half-life and AUC values were 0.98 hour and 20.7 micrograms.hr/ml. The mean peak urinary concentrations of CFPZ and 6 hours recovery rates were over 200 micrograms/ml at 2-6 hours and 27.6%, respectively. 2. Clinical efficacy of CFPZ was investigated in a total of 41 children, including 14 with upper respiratory tract infections, 6 with acute bronchitis and pneumonia, 2 with acute otitis media, 3 with skin and soft tissue infections and 16 with urinary tract infections. The clinical efficacy rate was 95.1%. The bacteriological eradication rate was 84.6%. 3. Two patients showed abnormal laboratory test results. One had elevations of both GOT and GPT, and another had eosinophilia which were attributed to this antibiotic as side effects.

Bacteria↗
PubMed1992

[The influence of cefdinir on the intestinal bacterial flora].

The influence of cefdinir (CFDN), a new oral cephalosporin, on the intestinal bacterial flora was studied in tetra-contaminated mice and in pediatric patients. CFDN in fine granules was administered at a dose of 10 mg/kg once a day for 5 consecutive days to mice contaminated with 4 different species of organism: Escherichia coli, Enterococcus faecalis, Bacteroides fragilis and Bifidobacterium breve. No remarkable changes were observed in the fecal viable cell counts except that decreases in E. coli counts were observed on the day 3 to 5 after starting administration. The subjects in pediatric study were 7 children with infections, 3 boys and 4 girls, with their ages from 6 months to 12 years 7 months. Their body weights ranged from 5.5 to 29.2 kg. CFDN fine granules was administered at each dose of 3.0 mg/kg to 3.7 mg/kg, 3 times a day for 4 to 14 days. During the administration of CFDN, some variations were observed in the pattern of changes in the fecal bacterial flora between subjects. Although Enterobacteriaceae and total counts of anaerobes were markedly decreased in 2 cases, total counts of aerobes were unchanged in the 2 cases, whereas main aerobes and anaerobes except enterococci hardly varied in the other cases. There was no case in which glucose non-fermenting Gram-negative rods and fungi became predominant species continually. Although Clostridium difficile and C. difficile D-1 antigens were detected in 1 and 4 cases, respectively, no relationship was found between the number of C. difficile and the characteristics of the feces. With regard to the drug sensitivities of bacteria isolated from feces before and after administration of CFDN, higher levels of resistance were found in some bacteria such as Enterococcus and Bacteroides during or after administration than before administration. CFDN was detected in fecal samples from 2 cases during administration with concentrations ranging between 0.99-254 micrograms/g. High value of CFDN was found in a case with low beta-lactamase activity in feces, in which marked decrease of Enterobacteriaceae and total counts of anaerobes was observed. The above results suggest that CFDN is considered to be a drug with relatively small influence on the intestinal bacterial flora. But as high concentrations of drugs were detected in feces under some circumstances, our attention will be required. Particular care is also required for the occurrence of diarrhea and microbial replacement during continuous, long-term administration of the drug.

Animals↗
PubMed1992

[Bacteriological and clinical studies on meropenem in the pediatric field].

Bacteriological and clinical studies have been performed on meropenem (MEPM, SM-7338), a newly developed carbapenem antibiotic, in the pediatric field. 1. Antibacterial activities of MEPM against 24 clinical isolates were determined. MEPM showed excellent activity against Gram-positive bacteria including Staphylococcus aureus and Gram-negative bacteria, especially Escherichia coli and Branhamella catarrhalis. Against Haemophilus influenzae, MEPM had a higher activity than imipenem and flomoxef, but had a lower activity than piperacillin and cefoperazone. 2. Clinical efficacies of MEPM were evaluated in 32 cases with bacterial infections. A poor efficacy was observed in 1 patient with phlegmon but excellent or good efficacies were obtained in other 31 patients with tonsillitis (1), pneumonia (17), UTI (12), or SSSS (1). The overall efficacy rate was 96.9%. All strains except 1 of S. aureus were eradicated by the administration of MEPM, and a high eradication rate of 95.8% (23 out of 24 strains) was obtained. 3. No side effects were observed in 35 evaluated cases. As abnormal laboratory test results, elevated GOT, elevated GPT, eosinophilia and neutropenia were noted in 4, 4, 4 and 2 patients, respectively. 4. Influences on blood coagulation parameters were studied. PIVKA II was elevated upon administration of MEPM in some cases, but no changes in ATT, TT, HPT or Fbg were observed during the treatment. Based on the above results, it has been concluded that MEPM is a safe and effective drug to use in the treatment of pediatric infections. The usual recommended dosage and administration should be 10 to 20 mg/kg of MEPM at a time, using intravenous drip infusion, 3 times a day.

Adolescent↗