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Biomedical subjects

S Iwata

Publications and source records attributed to S Iwata.

At least 361 records · Page 20Linked to original sources
PubMed1987

[A pharmacokinetic study in (mature and premature) neonates treated with amikacin through intravenous drip infusion].

A pharmacokinetic study was conducted in neonates (mature, premature) to which amikacin (AMK) was administered through intravenous drip infusion. The results of the study are summarized below. 1. Changes in blood concentrations of AMK obtained after intravenous drip infusion over a period of 30 or 60 minutes were comparable to those after intramuscular injection. 2. When AMK was administered to neonates (mature, premature) at a single intravenous (30 or 60 minutes) dose of 6 mg/kg, peak levels of 15.5 to 26.3 micrograms/ml were attained. These values were within the range of 15 to 30 micrograms/ml which are considered to be safe and effective peak levels. 3. In 0 day-neonates, half-lives of blood AMK levels rather long and widely varied (3 to 8 hours) but, in about 7 day-neonates, half-lives were 3 to 4 hours. 4. It is considered from the above results that the safe and effective blood concentrations of AMK in 0 to 7 day-old neonates can be obtained from intravenous administrations at each dose of 6 mg/kg repeated with intervals of 12 or 24 hours and, in 8 days or older neonates, from intravenous drip infusions over 30 or 60 minutes at each dose of 6 mg/kg repeated with intervals of 12 hours. 5. For neonates with very low birth weights, individual doses and intervals should be separately investigated.

Age Factors↗
PubMed1987

[Adrenal myelolipoma: a report of a case].

This is a case report of an adrenal myelolipoma, accidentally diagnosed during a work-up for bladder tumor. A 67-year-old male presented with the chief complaint of gross hematuria. He was subsequently diagnosed as having a bladder tumor, which was resected transurethrally and was found to be a transitional cell carcinoma of Grade 2 and Stage pT2. During further examination for metastasis computed tomography (CT) scan revealed a round tumor (approximately 5 cm in diameter) in the left adrenal. A tentative diagnosis was reached based on the scan, and surgery was undertaken to remove the tumor. A well-encapsulated tumor, yellowish and partly dark brown in color and 60 grams in weight, was retrieved. The tumor consisted of mature lipoid cells with myeloid cells scattered among them which verified the pathological diagnosis of adrenal myelolipoma. The present case is the 16th clinical case of adrenal myelolipoma reported in the Japanese literature.

Adrenal Gland Neoplasms↗
PubMed1986

Evaluations on the usefulness of viscous agents in anterior segment surgery. I. The ability to maintain the deepness of the anterior chamber.

Maintenance of the deepness of the anterior chamber is necessary to prevent the direct contact of surgical instruments with the corneal endothelium. Therefore, in this study, we measured the ability of viscous agents to maintain the deepness of the anterior chamber in vitro and discussed the correlations between this ability and the viscosity or elasticity of the various viscous agents. A 1% solution of sodium hyaluronate with a molecular weight of 2160 X 10(3) which has the highest viscosity and elasticity showed the best ability to maintain deepness. A 2% solution of methylcellulose with a molecular weight of 86 X 10(3) and a 1% solution of sodium hyaluronate with a molecular weight of 790 X 10(3) were also useful in maintaining the deepness. On the other hand, a 50% solution of sodium chondroitin sulfate with a molecular weight of 30 X 10(3), which has a higher viscosity but a lower elasticity than methylcellulose or sodium hyaluronate with a molecular weight of 790 X 10(3), was unable to maintain sufficient deepness. A 1% solution of sodium hyaluronate with a molecular weight of 250 X 10(3) which has the lowest viscosity and elasticity was completely ineffective for maintaining deepness. These results suggest that the ability to maintain the deepness of the anterior chamber depends on the elasticity of the viscous agent rather than its viscosity.

Animals↗
PubMed1986

Corneal permeability of aldose reductase inhibitor, M79175. I. In vitro study using corneal permeability apparatus.

Transcorneal permeability of M79175, aldose reductase inhibitor (Eisai), and various factors influencing it were examined using excised rabbit cornea mounted on the methacrylate apparatus. High permeability was exhibited and this was independent of the concentration of M79175. Cornea hydrated by exposure to the eye drop solution of high concentration of benzalkonium chloride, which had an enhancing effect on the permeability of M79175. Corneal hydration was also caused by the solution of low pH. These findings will show the basic conditions for this eye drop solution to be an artificial tear fluid.

Aldehyde Reductase↗
PubMed1986

Corneal permeability of aldose reductase inhibitor, M79175. II. In vivo study on pharmacokinetic aspect.

Transcorneal permeability of M79175 was estimated in vivo and the effects of pH and thickening agent on it were examined. The aqueous humor concentration of M79175 versus time profile showed the peak concentration of 850 ng/ml at 20 min after instillation of pH 7.0 eye drop solution. The permeability constant of M79175 was estimated by applying a physiologically based pharmacokinetic model to this profile. As was expected from the results in vitro, high permeability constant was observed in vivo. Lowering the pH of the solution demonstrated the tendency to decrease the concentration at 20 min. Thickening agent, Hydroyethylcellulose, did not change the aqueous humor concentration versus time profile. Ocular tissue distribution was examined using 14C-M79175. As was expected from the results of corneal permeability, high levels of M79175 accumulated to the lens.

Aldehyde Reductase↗
PubMed1986

Ultrastructural study of rainbow trout lenses incubated under various conditions.

The pathology of rainbow trout lenses incubated in various media and at various temperatures was examined by electron microscopy. After incubation at 0 degrees C for 5 h, no changes were observed in transparency and cytology. Irreversible warm cataract occurred at 37 degrees C, which corresponds to the body temperature of mammals. The degree of turbidity increased depending on incubation time. The ultrastructure of warm cataract in short-term incubation was characterized by the appearance of dense substances in the epithelium and swelling of the lens fibers. When the incubation time was prolonged up to 3 h, the turbidity increased and cellular disorders became severe. The volume of the dense substances increased also. A slight but detectable haziness of the lens was observed after incubation with calcium-free medium. Pathological findings in this case consisted of disorders of the intracellular membrane system in the epithelium and swelling of the lens fibers. These results suggest that the rainbow trout lens has a lower optimum temperature compared to the mammalian lens but requires the same Ca2+ concentration.

Animals↗
PubMed1986

[Influence of cefroxadine dry syrup on intestinal bacterial flora].

Influence of cefroxadine (CXD) dry syrup on intestinal bacterial flora was studied in mice infected with 4 species of bacteria, namely, Escherichia coli, Enterococcus faecalis, Bacteroides fragilis and Bifidobacterium breve, and in pediatric patients having infections in the respiratory tract and cutaneous/soft tissues. The results were summarized as follows: CXD dry syrup was administered for 5 consecutive days to mice infected with the 4 species. No considerable changes were observed in levels of bacteria in the feces and in different parts of digestive tracts. Eleven pediatric patients were orally administered with 30-54 mg/kg of CXD dry syrup a day for 7-15 consecutive days. Symptom of diarrhea was noted in 2 patients. Dominant species of the intestinal flora such as E. coli, Bifidobacterium, and Bacteroides sometimes decreased in patients treated with CXD dry syrup. In general, however, decreases in numbers of these bacteria were insignificant. Changes of intestinal flora in patients treated with CXD dry syrup were apparently smaller than those treated with ampicillin and were similar to those treated with cephalexin or amoxicillin.

Animals↗
PubMed1986

[Fundamental and clinical evaluation of ceftazidime in neonates and premature infants].

Fundamental and clinical evaluation of ceftazidime (CAZ) were carried out in neonates and premature infants, and the results obtained are summarized below. Serum concentrations of CAZ after administration of 20 mg/kg were satisfactorily high regardless of the route of administration; bolus intravenous injection or 1-hour intravenous drip infusion. Like other cephem antibiotics, half-lives tended to be shorter as day-ages of subject became higher. Although there were some differences in urinary recovery rates between different dosage groups, they were generally high. Clinical efficacy was either excellent or good in all 21 assessable cases. In 23 cases examined for adverse effects, diarrhea was observed in 1 case, and elevation of GOT and GPT, in another case.

Bacterial Infections↗
PubMed1986

[Pharmacokinetic and clinical evaluation of ceftazidime in neonates and premature infants].

Pharmacokinetics and clinical efficacy of ceftazidime (CAZ) were evaluated in neonates. The results obtained are summarized below. After a bolus intravenous injection of 20 mg/kg CAZ to neonates, peak serum concentrations ranged 55.1-97.4 micrograms/ml with the mean half-life of 2.26 hours in neonates with birth weight of 2,500 g or more, and 59.3-60.7 micrograms/ml with half-lives ranging from 3.98 to 4.22 hours in neonates weighing less than 2,500 g at birth. In the time-course observation, it was noted that the half-life at 2 days after birth was longer than half-lives observed on 4 and 9 days after birth. Four cases were given CAZ for treatment, and 3 cases for prophylaxis of infections, and the clinical efficacy was either excellent or good in all of the cases. Neither adverse effects nor abnormal laboratory findings were observed except rash in 1 case. Intestinal flora was examined in 5 cases. It was found that the effect of CAZ was less than that of LMOX, although some delay was seen in the growth of intestinal flora. There was no vitamin K deficiency in any of 6 cases examined.

Bacterial Infections↗
PubMed1986

[Basic and clinical studies of cefotiam in neonates and premature infants].

The effect of cefotiam (CTM) on neonates and premature infants was examined in basic and clinical studies. Minimum inhibitory concentrations of CTM against 190 clinically isolated strains kept by this department were investigated. This drug was found to have a strong antibacterial effect against Escherichia coli, Klebsiella spp., Proteus mirabilis and Streptococcus agalactiae, Staphylococcus aureus and Staphylococcus epidermidis, although some strains were resistant. The CTM was given to 0-3, 4-7, and greater than or equal to 8 day-old premature infants and neonates by intravenous injection at the dose of 20 mg/kg, and we studied changes in serum CTM levels over time. Mean serum CTM levels were 62.3 micrograms/ml at 15 minutes and 16.4 micrograms/ml at 6 hours after the injection, with the half-life of 3.6 hours, for the 0-3 day-old premature infants. They were 38.5 micrograms/ml at 15 minutes and 10.1 micrograms/ml at 6 hours, with the half-life of 2.9 hours, for the 0-3 day-old neonates. Those levels were 22.5 micrograms/ml at 15 minutes and 2.9 micrograms/ml at 6 hours, with the half-life of 1.9 hours, for the 4-7 day-old neonates, and 51.8 micrograms/ml at 15 minutes and 1.0 micrograms/ml at 6 hours, with the half-life of 1.1 hours, for the greater than or equal to 8 day-old neonates. The CTM was given to 0-3 and greater than or equal to 8 day-old premature infants and neonates by 1-hour intravenous drip infusion at the dose of 20 mg/kg, and changes in serum CTM levels after the infusion were followed. The 0-3 day-old premature infant (there was only one subject) had a peak serum CTM level of 21.0 micrograms/ml 1 hour after the start of the infusion (that is, at the time of its completion), with the level decreased to 8.6 micrograms/ml at 7 hours and the half-life was 5.4 hours. The mean peak serum CTM level in 0-3 day-old neonates were 36.7 micrograms/ml at 1 hour, which decreased to a mean of 7.0 micrograms/ml at 7 hours; the half-life was 2.3 hours.(ABSTRACT TRUNCATED AT 400 WORDS)

Bacterial Infections↗
PubMed1986

Studies of eye lens in poikilothermal animals. III. Long-term incubation of rainbow trout lenses.

Long-term incubation of the lens of rainbow trout, a cold water fish, can be carried out at 0 degrees C, without altering its transparency. This is not possible in mammalian lenses. Rainbow trout lenses maintained their transparency with normal cation levels for 2.5 months in H10 medium, which is a simple balanced salt solution containing glucose. In addition, lactic acid was detected and it was increased depending on the incubation time. However, lactic acid production ceased in glucose-free H10 medium after 10 days and the lenses became cloudy with an increase in Na+ and Ca2+ levels and a decrease in K+ and Mg2+ levels after 14 days. Therefore, rainbow trout lenses need glucose as the energy source to maintain the transparency and cation levels in vitro at 0 degrees C for more than 14 days. Lenses maintained their transparency and normal cation levels in H10 medium with 10% fetal bovine serum (FBS) for 12 months, in Dulbecco's modified Eagle medium (DME medium) for 10 months and in DME medium with 10% FBS for 6 months. FBS, amino acids and vitamins are effective to maintain the transparency of the incubated lenses for a long time. The lactic acid production rate was 8.3 micrograms per day in H10 medium and H10 medium with FBS, and 16.5 micrograms per day in DME medium and DME medium with FBS. These results suggest that the restricted H10 medium with FBS is suitable to maintain the transparency of the incubated lenses rather than the nutritious DME medium with or without FBS.(ABSTRACT TRUNCATED AT 250 WORDS)

Amino Acids↗
PubMed1986

[Follow-up cytology in the management of urotheliomas].

Ninety-one patients with operation history for urotheliomas were followed-up by urinary cytology for 17.5 months on the average. Cytologically, fresh urine was examined every month and vesical irrigation fluid every three months. Cystoscopy was also performed every three months, IVP every six months, and biopsy was performed when carcinoma or dysplasia was suspected. As a result, cases were classified into four groups. Group 1: All cytological examination were negative. Group 2: Cytology was positive for two or three months after TUR-Bt during which period vesical instillation therapy of anti-cancer drugs was performed, but was negative after this period. Group 3: Positive and negative cytology were diagnosed irregularly. Group 4: All cytological examinations were positive. The numbers of cases classified into these groups were 27 (29.7%), 7 (7.7%), 43 (47.3%) and 14 (15.4%), respectively. Tumor recurrence was seen in 1/27 (3.7%), 0/7, 12/43 (27.9%) and 4/14 (28.6%) cases, respectively. Metastasis was seen in only five cases of the group 4. Tumor recurrence and positive urinary cytology at the same time were seen in nine cases (20.9%) of group 3, and eight cases (57.1%) of group 4. Thirty four cases (79.1%) with discrepancy of cytological and endoscopic findings in group 3, in which cases 20 cases had only positive irrigation cytology and 11 cases had positive fresh urine and irrigation specimens, were more suspicious of temporary existence of in situ carcinomas or dysplastic urothelium. Of six cases with the discrepancy in group 4, three cases were in situ carcinoma diagnosed by random biopsies, and four cases had positive cytologies after TUR-Bt continuously.(ABSTRACT TRUNCATED AT 250 WORDS)

Carcinoma in Situ↗