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Biomedical subjects

K Iwamoto

Publications and source records attributed to K Iwamoto.

At least 253 records · Page 14Linked to original sources
PubMed1981

Management of malignant hyperthermia.

A case of malignant hyperthermia in a young girl with vesicoureteral reflux and multiple congenital abnormalities is discussed. Malignant hyperthermia is a relatively newly defined problem that is associated with anesthesia. It is being recognized with increasing frequency, particularly in children with multiple musculoskeletal anomalies. The term itself is a misnomer. It is a drug-induced syndrome of hypermetabolism that may represent an inborn error of metabolism. Recognition, prophylaxis and crisis management are reviewed, and the use of dantrolene sodium in the care of patients with malignant hyperthermia is discussed. Because recognition of malignant hyperthermia is an important concern for the practicing urologist, the principles of identifying the patient at risk, as well as managing the crisis, should be familiar to the clinician.

Abnormalities, Multiple↗
PubMed1981

Anaesthesia for an unusual carcinoid metastasis.

The intra-operative course of a patient found to have a metastatic serotonin-secreting carcinoid tumour in the orbit is reported. No prophylactic or intra-operative therapy was necessary during the administration of enflurane anesthesia. This case demonstrates again the wide spectrum of clinical responses observed among patients with this disease.

Anesthesia, Inhalation↗
PubMed1981

Distribution of creatinine following intravenous and oral administration to rats.

To evaluate the distribution of creatinine in rats, urinary, fecal and expiratory excretion, plasma levels and whole-body autoradiography following intravenous or oral administration of [carbonyl-14C]creatinine was investigated. More than 90% of the exogeneous creatinine was excreted in the urine in 24 hr following intravenous administration, and both fecal and expiratory excretion were only about 1%. In case of oral administration, however, it was found that expiratory excretion could not be neglected, ranging from about 1 to 30%. Plasma creatinine concentration-time curves following the intravenous administration (70.4 micrograms/kg or 400 mg/kg as creatinine) were analyzed according to a two-compartment open model. There were significant but very small differences in the pharmacokinetic parameters for these two doses. When these parameters were compared with those of urea, k12 and k21, which are transfer rate constants between compartment 1 and 2, for creatinine were significantly smaller than those of urea. On the other hand, k10 was larger in creatinine. Furthermore, (V'd)extrap for creatinine was about three times that of urea. Whole-body autoradiograms at 5 minutes following intravenous administration showed that exogeneous creatinine distributes with higher concentrations in liver, lung and kidney than in muscle and fat. This results was remarkably different from that of urea which distributes almost uniformly throughout the body at the same time. This difference observed in the autoradiograms would be the consequence of the fact that urea has larger k12 and k21 than creatinine.

Administration, Oral↗
PubMed1981

Excretion of indomethacin into saliva following intravenous administration to dogs.

Parotid saliva (Pr) and mandibular-sublingual saliva (MS) were collected separately by means of permanent fistulae in order to investigate the excretion of indomethacin in saliva of dogs receiving a single intravenous dose of 20 mg/kg. Drops of citric acid solution were placed on the tongue to stimulate salivary secretion. The concentrations of indomethacin both in saliva and plasma declined biexponentially with time. There was a good linear relationship between the drug concentration in each saliva and plasma. The Pr and MS levels were 7.4% and 4.4% of the plasma levels, respectively. Indomethacin concentrations in Pr were significantly higher than in MS (p less than 0.05). The roles of salivary pH and salivary protein binding were discussed in respect to the mechanism of salivary excretion of the drug.

Animals↗
PubMed1981

Disposition of creatinine and urea in bilaterally nephrectomized rats.

Bilaterally nephrectomized rats were used to investigate the disposition of creatinine when renal function is acutely decreased. The percentage of radioactivity recovered in the expired air in 11 hours following intravenous administration of [carbonyl-14C] creatinine immediately and 24 hours after nephrectomy was 0.54 and 3.24% respectively, and these values were significantly different (p less than 0.05). As it was considered that expiratory excretion is one of the major elimination routes in nephrectomized rats, mechanism of expiratory excretion was investigated by incubating [carbonyl-14C] creatinine with the intestinal contents of the rats chronically loaded with creatinine [carbonyl-14C] Creatinine was completely metabolized in that intestinal contents, but 14CO2 was not produced. When the mixture of the metabolites was administered orally or intravenously to chronically creatinine loaded rats, however, about 50% of the total radioactivity was excreted into the expired air in 5 hours. Furthermore, biliary excretion of the radioactivity following intravenous administration of [carbonyl-14] creatinine in the nephrectomized rats was much greater than that in normal rats. These results indicate that expiratory excretion following intravenous administration [carbonyl-14C] creatinine to nephrectomized rats would arise following intestinal absorption of the creatinine metabolites, which seem to be produced by intestinal microflora after biliary excretion of creatinine. The change of disposition for urea by bilaterally nephrectomy was also studied to compare with that for creatinine.

Administration, Oral↗
PubMed1981

Protein binding effects of salivary excretion of phenobarbital in dogs.

The salivary excretion of phenobarbital was investigated by collecting parotid saliva (Pr) and mandibular-sublingual saliva (MS) separately after intravenous administration in beagle dogs. (1) The alterations in the proportions of saliva secreted by the different glands were produced by salivation stimulants such as citric acid, ascorbic acid, sodium chloride and sodium glutamate. (2) The phenobarbital concentrations in both Pr amd MS were lower than those in plasma. The drug concentrations in MS were significantly lower than in Pr with stimulus of 10% citric acid of 15% sodium chloride (p less than 0.05). There was a significant correlation between phenobarbital concentration in each saliva and plasma specimen ( p less than 0.05). (3) The stimulation with 10% citric acid produced higher saliva /plasma drug concentration ratios (S/P ratios: 0.923 +/- 0.175 for Pr, 0.633 +/- 0.073 for MS) than that with 15% sodium chloride (S/P ratios: 0.597 +/- 0.071 for Pr, 0.509 +/- 0.067 or MS). (4) The S/P ratios were hardly influenced by salivary flow rates, at least under the experimental conditions examined in this study. (5) The increased S/P ratios were observed with higher salivary pH and then the equation of Matin et al. 3) seemed to hold for the average values of salivary pH and S/P ratio. (6) The stimulation with 10% citric acid produced higher protein concentration in saliva and higher S/P ratio than that with 15% sodium chloride following alternate stimulations in the same dog.

Animals↗
PubMed1981

Hypnosis in high risk ophthalmic surgery.

Hypnosis is an effective tool in many areas of medicine and surgery. The exacting demands of ophthalmic surgery require good patient cooperation and strict adherence to treatment regimens. Multisystemic diseases compounded by the physiological stress of surgery make it essential that already strained homeostatic mechanisms are interfered with minimally. The cases presented in this report illustrate the beneficial use of hypnosis in the treatment of several high risk patients in unusual situations.

Adult↗
PubMed1980

Liposomal membranes. VI. Polysaccharide-induced aggregation of multilamellar liposomes of egg lecithin.

Induced aggregation of multilamellar liposomes of egg lecithin with several polysaccharides, such as pullulan, dextran, hydroxyethylstarch, and amylopectin, has been investigated in conjunction with structural characteristics of polysaccharides, incubation temperature, ionic strength, and surface charge of liposomes. Aggregation of liposomes as a function of time was followed by monitoring turbidity of the liposome suspension at 600 nm. The inverse relationship between the minimal concentration and molecular weight of polysaccharides for the induced aggregation of liposomes was observed for all the polysaccharides employed. Polysaccharides having larger excluded volume more easily bind to liposomes, leading to the acceleration of the aggregation of liposomes. Hence, the order of efficiency of polysaccharides for the promotion of liposome aggregation was pullulan greater than dextran greater than hydroxyethylstarch congruent to amylopectin. Increasing the surface charge of liposomes brought about a decrease in aggregation irrespective of the sign. Even when negatively charged liposomes were incubated with the cationic DEAE-dextran, the liposome aggregation was depressed. These results including salt effect and temperature dependency of the induced aggregation of liposomes supported a plausible mechanism for the reaction, the polysaccharide-bridging mechanism, which has been provided for the polysaccharide-promoted agglutination of human erythrocytes.

Chemical Phenomena↗
PubMed1979

Inactivation of the mitogenic property of pokeweed mitogen by erythrocytes.

In whole blood culture, pokeweed mitogen (PWM) is unable to stimulate human lymphocytes. This is because the mitogenic property of PWM is inactivated by erythrocytes, presumably due to absorption. The inactivation was observed with as few as 5 x 10(6)/ml of human erythrocytes. Therefore, when PWM is used to study the functions of human lymphocytes, especially of suppressor T lymphocytes, erythrocytes should be removed from lymphocyte preparations for accurate analysis.

Absorption↗
PubMed1978

Antiemetic effect of droperidol after ophthalmic surgery.

Postoperative nausea with emesis is an undesirable side effect of general anesthesia in patients who have undergone ophthalmic surgery. The antiemetic effect of intravenous droperidol (Inapsine) was measured in a double-blind, controlled study of 78 patients undergoing general (enflurane [Ethrane]) anesthesia for a variety of ophthalmic procedures. There was a significant difference in the incidence of postoperative nausea and/or emesis in the droperidol-treated group, 13 of 78 (16%) as compared with the control population (37 of 87 [42%]). No complications of droperidol administration were observed. Droperidol may be an effective antiemetic drug if used prophylactically in patients who receive general anesthesia for ophthalmic surgery.

Adolescent↗