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Biomedical subjects

S Iwata

Publications and source records attributed to S Iwata.

At least 397 records · Page 22Linked to original sources
PubMed1985

Biochemical studies on the use of sodium hyaluronate in the anterior eye segment. III. Histological studies on distribution and efflux process of 5-aminofluorescein-labeled hyaluronate.

5-aminofluorescein-labeled hyaluronate was injected into the anterior chamber of rabbit eyes, and its distribution in the anterior segment and efflux process from the chamber were investigated. At an early stage after the injection, fluorescence was observed in the iris and corneo-scleral junction. The labeled hyaluronate in the lysosome separated from the iris had been degraded remarkably at this stage. These results suggest that the labeled hyaluronate injected into the chamber is eliminated not only through the aqueous plexus/sinus of the chamber angle but also through the iris and corneo-scleral junction by digestion with lysosomal hyaluronidase in the iris. On the other hand, fluorescence was observed at and after 12 hours in the corneal stroma. This finding means that a part of the labeled hyaluronate that had been distributed in the corneo-scleral junction permeated into the central part of the cornea through the extracellular space of the corneal stroma. Fluorescence could not be detected in the lens and ciliary body at any period after the injection.

Animals↗
PubMed1985

Retroperitonealization for quick splenic salvage during transperitoneal nephrectomy.

During intraperitoneal nephrectomy, the spleen may be injured inadvertently. Splenic salvage is mandatory in this situation; however, it requires some skill and extra time to control the bleeding. The authors present a very simple technique to replace the organ and retroperitonealize it in the nephrectomized fossa after some suture ligations have been placed in the major bleeding site.

Carcinoma, Renal Cell↗
PubMed1985

[Fundamental and clinical studies on aztreonam in pediatrics].

Fundamental and clinical results of AZT in pediatrics were as follows. Pharmacokinetics of AZT was studied for 1 case with resulting high serum concentration and a half-life of approximate 1 hour. AZT was administered to 10 patients with bacterial infections with 100% clinical efficacy and 62.5% bacterial elimination. Side effect was 1 case of diarrhea. There were no abnormal laboratory or coagulation test findings nor vitamin K deficiency, platelet hypofunction or effects on intestinal bacterial flora. AZT was considered to be high in safety. The administration of 20 mg/kg AZT 3 times a day was considered to be an effective treatment for pediatric Gram-negative infections.

Adolescent↗
PubMed1985

Constitution of the greater splanchnic nerve in the rat.

The greater splanchnic nerve originating from the sympathetic ganglia between the 10th and 12th ribs on the dorsal thoracic wall passes through the diaphragm between its medial and lateral erura, to form the celiac plexus around the celiac trunk and superior mesenteric artery in the abdominal cavity. The nerve consists of about 10,000 of nerve fibers and of 25,000 of ganglion cells in its whole length of 2.5 cm; nerve fibers can be divided into myelinated fibers, accounting for less than 6% of total numbers, and unmyelinated fibers, which amount to more 90%. Special attention was not paid to the numerous ganglion cells in terms of their shapes, sizes, and cell organelles except for a small number of binucleate cells. However, the nerve contains remarkable synapses that connect between axon showing flat, elliptical, and cored vesicles and dendrite, between another type of axon having elliptical and cored vesicles and dendrite, and even between dendrite and cell body, in which synaptic vesicles are small spherical and elliptical. These facts can suggest that the greater splanchnic nerve contains more complex structure than has been hitherto described.

Animals↗
PubMed1984

The influence of cefotaxime on intestinal flora and bleeding diathesis in infants and neonates, compared with other beta-lactams.

Various second- and third-generation cephem antibiotics were administered to infants 2 years of age or less. Excluding Streptococcus faecalis, which is resistant to cephems, all of the intestinal bacteria decreased in number, and in many cases these were replaced by yeasts. A positive reaction for protein induced by vitamin K absence or antagonism (PIVKA II) occurred in 25 to 63% of the subjects administered cephems possessing a methylthiotetrazole group, but not in those dosed with cefotaxime or ceftazidime. The effects of cefotaxime and latamoxef (moxalactam) on platelet ADP aggregation were also investigated. When these drugs were administered to clinical patients, moxalactam showed stronger inhibition of aggregation than cefotaxime.

Adenosine Diphosphate↗
PubMed1984

Biochemical studies on the use of sodium hyaluronate in the anterior eye segment. I. Variation of protein and ascorbic acid concentration in rabbit aqueous humor.

To investigate the safety of the use of sodium hyaluronate in anterior segment surgery, the changes in protein, ascorbic acid and hyaluronate concentration in the aqueous humor, and intraocular pressure were followed after sodium hyaluronate was injected into the anterior chamber. When a 1% solution of sodium hyaluronate with a molecular weight of 800K was injected, the recovery patterns of protein and ascorbic acid concentration to normal levels were the same as the recovery patterns after injection of phosphate buffered saline which was the solvent for sodium hyaluronate. However, when a 1% solution of sodium hyaluronate with a molecular weight of 1640K or a 2% solution with a molecular weight of 800K was injected, it was observed that the recovery times of protein and ascorbic acid concentration to normal levels were longer than that required after injection of 1%, 800K sodium hyaluronate. Further, the recovery time of the aqueous humor components to normal levels was associated with the clearance time of sodium hyaluronate from the anterior chamber. The transient increase in intraocular pressure by injection of sodium hyaluronate was observed, but it disappeared in 12 hrs. The recovery time of intraocular pressure to normal level was independent of molecular weight and concentration of sodium hyaluronate tested.

Animals↗
PubMed1984

Biochemical studies on the use of sodium hyaluronate in the anterior eye segment. II. The molecular behavior of sodium hyaluronate injected into anterior chamber of rabbits.

The behavior of sodium hyaluronate injected into the anterior chamber of rabbits was investigated using a 1% (w/v) solution of sodium hyaluronate having a molecular weight of 800K. Although the aqueous humor contained a considerable amount of reduced ascorbic acid, the molecular weight of sodium hyaluronate injected into the anterior chamber did not change. This was due to existence of a protecting factor for degradation of sodium hyaluronate in a low molecular weight fraction of the aqueous humor. The injected sodium hyaluronate was found to aggregate with proteins in the aqueous humor within 2 hrs. However, this aggregation did not affect the degradation of sodium hyaluronate with ascorbic acid. The hyaluronic acid content in the iris-ciliary body increased about three times as much as the normal level 2 hrs after the sodium hyaluronate injection. This result suggests that the injected sodium hyaluronate is not only eliminated through the angular aqueous plexus but also through the iris-ciliary body, followed by digestion with hyaluronidase in those tissues.

Animals↗
PubMed1984

Biochemical studies on the use of sodium hyaluronate in the anterior eye segment. IV. The protective efficacy of the corneal endothelium.

We devised an apparatus to add constant mechanical force to the corneal endothelium, and the protective efficacy of sodium hyaluronate to the corneal endothelium was determined quantitatively using an image analyzer. When the corneal endothelium was coated with a 1% solution of 800K or 2150K sodium hyaluronate, the damaged area was significantly less than cases having a coating with a 1% solution of 200K sodium hyaluronate or phosphate buffered saline which was the solvent of sodium hyaluronate. The water uptake of damaged cornea was also investigated using tritiated water. The cornea coated with 800K or 2150K sodium hyaluronate showed the same water uptake as the normal cornea, but the cornea coated with 200K sodium hyaluronate or phosphate buffered saline showed a significantly higher uptake. These results suggest that a 1% solution of 800K or 2150K sodium hyaluronate protects the corneal endothelium from mechanical damages.

Animals↗
PubMed1984

Activator of Ca2+-transport in the lens.

It has been hypothesized that an activator of Ca-ATPase co-exists with Ca-ATPase in the mouse lens. Though the Ca-ATPase activity could be measured from mouse lens homogenate, its activity could not be determined in individual soluble and insoluble fractions. The Ca-ATPase activity, however, could be detected when an activator of this enzyme such as calmodulin was added to the lens insoluble fraction. This enzyme in the lens insoluble fraction was activated also by addition of soluble fraction. The Ca-ATPase in homogenate was inhibited by chlorpromazine and N-(6-amino-hexyl)-5-chloro-1-naphthalenesulfonamide (W-7), which are calmodulin antagonists. When the mouse lens was incubated with W-7, the degree of the lens opacification increased in relation to W-7 concentration.

Animals↗
PubMed1984

[Fundamental and clinical studies of sulbactam/cefoperazone in the pediatric field].

Fundamental and clinical studies were carried out on sulbactam/cefoperazone (SBT/CPZ) in the field of pediatrics. The following results were obtained: A total of 185 clinical isolates that had been stocked at our department was employed to determine the minimum inhibitory concentrations (MICs) of SBT/CPZ against various bacterial species. SBT/CPZ showed strong antibacterial potency against E. coli, Salmonella, Klebsiella and P. mirabilis, and relatively strong potency against S. marcescens, P. aeruginosa and S. aureus. Antibacterial potency of SBT/CPZ was stronger than that of CPZ alone against E. coli, and it also showed strong activity against strains of Salmonella, S. marcescens and S. aureus, moderately or highly resistant to CPZ. SBT/CPZ was administered by intravenous bolus infusion to pediatric patients to determine the serum concentrations of SBT and CPZ. At a dose of 10 mg/kg the mean serum levels of SBT and CPZ were as follows; 17.8 micrograms/ml, 40.7 micrograms/ml at 15 minutes and 0.3 microgram/ml at 6 hours, respectively. The half-lives of SBT and CPZ in the serum were 1.05 hours and 1.76 hours, respectively. Similarly, at a dose of 20 mg/kg the mean serum levels of SBT and CPZ were; 31.9 micrograms/ml, 81.0 micrograms/ml at 15 minutes and 0.5 microgram/ml, 6.1 micrograms/ml at 6 hours, and the half-lives were 1.00 hour and 1.72 hours, respectively. At a dose of 40 mg/kg, only 1 case was determined. The serum levels of SBT and CPZ were 34.4 micrograms/ml, 74.8 micrograms/ml at 30 minutes and 0.2 microgram/ml at 6 hours, and the half-lives were 0.78 hour and 1.38 hours, respectively. SBT/CPZ was drip-infused intravenously over a period of 1 hour, and the serum concentrations of SBT and CPZ were determined. At the dose of 10 mg/kg or 20 mg/kg, the peak serum levels of SBT and CPZ were observed at 1 hour or at the end of drip infusion. At a dose of 10 mg/kg the mean serum levels of SBT and CPZ were 14.4 micrograms/ml, 33.7 micrograms/ml at 1 hour and 1.4 micrograms/ml, 4.6 micrograms/ml at 7 hours, respectively. The half-lives was 1.86 hours for SBT and 2.23 hours for CPZ, respectively. Similarly at a dose of 20 mg/kg, the mean serum levels of SBT and CPZ were, 22.2 micrograms/ml, 34.6 micrograms/ml at 1 hour and 0.5 microgram/ml, 2.8 micrograms/ml at 7 hours, and the half-lives was 1.17 hours and 1.75 hours, respectively. The urinary recovery rate was determined for the 6 hours period after administration.(ABSTRACT TRUNCATED AT 400 WORDS)

Age Factors↗
PubMed1984

[Fundamental and clinical evaluation of ceftriaxone in the field of pediatrics].

Fundamental and clinical evaluation on ceftriaxone (Ro 13-9904, CTRX) was performed in the field of pediatrics and the following results were obtained. The antibacterial activity of CTRX was determined against clinically isolated strains at our department. CTRX was definitely superior to CEZ and CMZ and almost equal or slightly superior to CTX in activity against Gram-negative bacteria, while the MIC of CTRX against Gram-positive bacteria was higher than that of CEZ and CMZ and about equal to that of CTX. The blood concentration of CTRX after one shot intravenous injection with 10 mg/kg was 67.98 micrograms/ml at 15 minutes, 51.96 micrograms/ml at 30 minutes, 37.51 micrograms/ml at 1 hour, 28.91 micrograms/ml at 2 hours, 20.71 micrograms/ml at 4 hours, 13.97 micrograms/ml at 6 hours and 6.45 micrograms/ml at 12 hours, while the half-life time was 3.74 hours. The blood concentration of CTRX after one shot intravenous injection with 20 mg/kg was 179.55 micrograms/ml at 15 minutes, 120.01 micrograms/ml at 30 minutes, 100.01 micrograms/ml at 1 hour, 53.75 micrograms/ml at 2 hours, 33.13 micrograms/ml at 4 hours, 26.41 micrograms/ml at 6 hours and 21.49 micrograms/ml at 12 hours, while the half-life time was 4.15 hours. The blood concentration of CTRX after intravenous drip infusion for 1 hour with 10 mg/kg was 19.54 micrograms/ml at 15 minutes, 27.19 micrograms/ml at 30 minutes, 36.57 micrograms/ml at 1 hour, 23.83 micrograms/ml at 2 hours, 19.69 micrograms/ml at 3 hours, 14.46 micrograms/ml at 5 hours, 11.02 micrograms/ml at 7 hours and 7.27 micrograms/ml at 13 hours, while the half-life time was 6.59 hours. The blood concentration of CTRX after intravenous drip infusion for 1 hour with 20 mg/kg was 61.72 micrograms/ml at 30 minutes, 108.1 micrograms/ml at 1 hour, 54.95 micrograms/ml at 2 hours, 35.68 micrograms/ml at 3 hours, 28.13 micrograms/ml at 5 hours, 20.51 micrograms/ml at 7 hours and 11.43 micrograms/ml at 13 hours, while the half-life time was 4.23 hours. There was noticed a tendency of the blood level being elevated by consecutive administration. The urinary recovery rate of CTRX ranged from 36.5 to 71.6%. The excretion rate of CTRX into the cerebrospinal fluid ranged from 5.2 to 11.6%. The excretion rate of CTRX into the pleural fluid was 31.0%. The clinical efficacy rate was 87.5% (excellent or good) in 8 children with infections treated with CTRX. The eradication of bacteria was observed in all of 5 cases bacteriologically evaluation.(ABSTRACT TRUNCATED AT 400 WORDS)

Adolescent↗
PubMed1984

[Fundamental and clinical evaluation of ceftriaxone in the pediatric field].

Fundamental and clinical evaluation of ceftriaxone (CTRX) was performed in the pediatric field and the following results were obtained. The MIC of CTRX against E. coli isolated from urinary tract infections in children ranged from less than or equal to 0.024 to 0.39 mcg/ml except for 1 strain. CTRX was superior to other 3rd generation cephalosporins such as CPZ and LMOX, showing effectiveness also against ABPC-resistant bacteria. The clinical efficacy and bacteriological efficacy in 6 children consisting of 5 with respiratory tract infections and 1 with urinary tract infection were 83% and 100%, respectively. As to the adverse reaction, diarrhea was observed in 2 cases. The determination of PIVKA-II performed during the therapy with CTRX, which is observed when vitamin K is deficient, showed positiveness in 2 cases out of 6 cases including 1 which the clinical efficacy could not be evaluated. The test of platelet function in 3 cases found no inhibition of agglutination. Twice-daily administration with 20 mg/kg CTRX was considered to be a useful and safe method for treatment of bacterial infections in children, although attention should be taken not to cause vitamin K deficiency as in other 2nd and 3rd generation cephalosporins.

Cefotaxime↗
PubMed1984

[Basic and clinical studies on ceftazidime in the pediatric field].

Basic and clinical studies were made on ceftazidime (CAZ) in pediatric field, and the following results were obtained. The antibacterial activity of CAZ against clinically isolated and maintained strains was examined. CAZ was unequivocally more active than CEZ and CMZ against Gram-negative rods, with MIC distribution similar to that of CTX, except for that for P. aeruginosa. The MIC of CAZ was lower than that of CTX for P. aeruginosa. Compared with the MICs of CEZ, CMZ and CTX, CAZ showed slightly higher MICs for Gram-positive bacteria. The blood concentrations of CAZ, at 0.25, 0.5, 1, 2, 4 and 6 hours after a one shot intravenous injection of 10 mg/kg of CAZ were 64.9, 36.9, 28.3, 14.7, 4.92 and 2.42 micrograms/ml, respectively, with the half-life of 1.27 hours. The blood concentrations of CAZ, at 0.25, 0.5, 1, 2, 4 and 6 hours after a 1-hour drip infusion of 10 mg/kg of CAZ were 16.6, 24.5, 41.4, 17.1, 5.38 and 2.62 micrograms/ml, respectively, with the half-life of 1.28 hours. The blood concentrations of CAZ, at 0.25, 0.5, 1, 2, 4 and 6 hours after a one shot intravenous injection of 20 mg/kg of CAZ were 73.1, 60.8, 39.3, 17.3, 8.23 and 4.45 micrograms/ml, respectively, with the half-life of 1.42 hours. The blood concentrations of CAZ, at 0.5, 1, 2, 4 and 6 hours after a 1-hour drip infusion of 20 mg/kg of CAZ were 55.1, 69.0, 32.1, 11.4 and 4.56 micrograms/ml, respectively, with the half-life of 1.27 hours. Urinary recovery rate of CAZ during the first 6 hours after a one shot intravenous injection of 10 mg/kg of CAZ was 86.7%. CAZ was administered to 17 children with infections, and the clinical response was excellent or good in 94%. CAZ was bacteriologically effective in 14 patients, all bacteria having been eradicated in them. The bacteria were E. coli in 10 patients, H. influenzae in 2, P. aeruginosa in 1 and S. pneumoniae in 1. As for side effects, slight elevation in GOT was observed in 1 case and eosinophilia, in another case.

Adolescent↗
PubMed1984

Resorption of microtubules and nucleus during the encystation process in Echinosphaerium nucleofilum.

The cyst formation process was investigated in a large heliozoan Echinosphaerium nucleofilum, with particular reference to the resorption of axonemal microtubules and nuclei into the cytoplasm. As the encystation proceeded, the axonemal microtubules were found to disassemble from their distal ends by being surrounded or invaded with many tubular vesicles, followed by detaching at their proximal ends from the nuclear envelope and by disassembling completely at the final stage. On the other hand, several nuclei were found to be enclosed by large vacuoles before they were destroyed or digested and finally absorbed into the cytoplasm. At this stage, one or two large multi-layered bodies were formed inside the nucleus. The meanings of the resorption of microtubules and nuclei were considered and discussed.

Animals↗