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Biomedical subjects

K Iwamoto

Publications and source records attributed to K Iwamoto.

At least 163 records · Page 9Linked to original sources

Expression of interleukin-2 receptor (IL-2R) in feline peripheral blood lymphocytes.

A monoclonal anti-interleukin-2 receptor (IL-2R) antibody has been identified as a putative antibody against the human IL-2R. In the present study, anti-Tac antibody CD-25 was used to determine cell expressing IL-2 receptor in feline peripheral blood lymphocytes by means of direct immunofluorescence tests and complement-mediated lymphocytotoxicity tests. With complement-mediated lymphocytotoxicity, approximately 18% of feline peripheral blood lymphocytes expressed the receptors. By the direct immunofluorescence test, we found approximately 22% of IL-2R positive cells in lymphocytes of feline peripheral-blood.

Animals↗

Cases of infective endocarditis caused by Campylobacter fetus.

An 18-year-old man with infective endocarditis caused by Campylobacter fetus is reported. This bacterial species has long been of interest in veterinary medicine, and recently it has been reported to be one cause of infantile diarrhea. Infective endocarditis arising from campylobacter fetus is rare. This is the fourth case reported in Japan. The organism was resistant to several antibiotics, and large vegetations were found to involve the aortic valve. Emergency excision of the infected aortic valve and replacement with a valve prosthesis were successful. Current clinical treatment of infective endocarditis is discussed, and the literature briefly reviewed.

Adolescent↗

[Clinical study of prostatic cancer].

Eighty patients with prostatic cancer, who first visited Kyorin University School of Medicine from January 1976 through December 1986, were analyzed. Incidence of prostatic cancer was 3.9% among male inpatients. Age distribution was between 55 and 88, with an average of 72 years old. The most common symptoms were dysuria followed by pollakisuria, hematuria, lumbago and lower extremity pain. Duration from onset of symptom to examination ranged from 6 to 84 months, with an average of 22 months. Clinical stage was A in 7.5%, B in 10%, C in 11.3% and D in 71.3%. According to histological grade, well, moderately, and poorly differentiated adenocarcinomas were observed in 29.9, 29.9 and 40.2%, respectively. According to the General Rules for Clinical and Pathological Studies on Prostatic Cancer, clinical T classification were T0 in 8.7%, T1 in 3.8%, T2 in 47.5%, T3 in 27.5% and T4 in 12.5%. In the correlation between stage and grade, the largest number of poorly differentiated adenocarcinoma cases was in stage D. There was no correlation between stage and T classification. Of the 80 patients, 71.25% were treated with antiandrogen therapy, 16.25% with radiation therapy chiefly, 7.5% by surgery chiefly, and 5% with chemotherapy. Survival rate was calculated by the Kaplan-Meier method. Overall survival rate of the 80 patients was 54.4% at 5 years. Survival rate by stage were 100% in stage A at 4 years, and 100% in B, 87.5% in C and 40.5% in D at 5 years.(ABSTRACT TRUNCATED AT 250 WORDS)

Adenocarcinoma↗

Role of the potential secondary structures in phage G4 origin of complementary DNA strand synthesis.

Phage G4 origin of complementary DNA strand synthesis (oric) consists of three stable stem-loop structures (I, II, and III). Mutant oric sequences with alterations in the structure of stem-loop II, stem-loop III, and the stem-loop II-III spacer region have been constructed and cloned into the filamentous phage vectors to assay their functional activity. Changes in the lowermost GC base pair in the stem of stem-loop III, in the 9-bp spacer region between the stems of stem-loops II and III, and in the loop of stem-loop II, impair or abolish in vivo oric function. The results suggest that recognition sequences for dnaG primase must be present in the loop of stem-loop II, and in the spacer region between the stems of stem-loops II and III.

Bacteriophages↗

Simultaneous determination of ofloxacin, fenbufen and felbinac in rat plasma by high-performance liquid chromatography.

Ofloxacin, fenbufen and its active metabolite, felbinac, were simultaneously extracted from 50 microliters of rat plasma and analysed by high-performance liquid chromatography on a reversed-phase column. Quantitative and reproducible determinations were possible for ofloxacin, fenbufen and felbinac over the concentration ranges 0.15-40, 0.3-80 and 0.45-45 micrograms/ml, respectively. The detection limits for all the drugs were lower than those reported previously. The recovery of ofloxacin, fenbufen and felbinac added to plasma was nearly 100% with a coefficient of variation of less than 3.0%. This method was found to be applicable to pharmacokinetic studies of each drug after the concomitant administration of ofloxacin and fenbufen.

Animals↗

Effective production of a human monoclonal antibody against tetanus toxoid by selection of high productivity clones of a heterohybridoma.

A mouse.human-human heterohybridoma, N12-16.63, has been described which produces an anti-tetanus toxoid human monoclonal antibody (MoAb). A clone, N12-16.63.49.19, which produces eight times as much MoAb as that produced by the original cell line, was selected by repeating the recloning and selection twice. Two clones, N12-16.63.49.19.69 and N12-16.63.49.19.127, further selected from this clone produced almost 20 times more than that produced by the original cell line. Though the production of MoAb by these clones gradually decreased with repeating transfers, they still produced a large amount of human MoAb even after 3 months of transfer. Human MoAb (IgM) was isolated from the culture supernatants of the original and high productivity clones and the products were confirmed to be identical. Human MoAb was effectively produced by batch culture on the 20 liter scale or a perfusion culture on the 1 liter scale using these high productivity clones.

Animals↗

Effect of perfused rat mandibular-gland pHI on the ratio of procainamide concentration in saliva to that in venous effluent.

The saliva to venous-effluent concentration ratio (S/E ratio) for procainamide (PA) was determined and compared with the ratio calculated by using the intracellular pH value of glandular cells. Exposed mandibular gland was perfused in situ with Krebs-Ringer bicarbonate buffer containing PA (10-100 micrograms/ml) and acetylcholine (ACh, 0.1 to 10 microM) or pilocarpine (10 microM). These perfusion conditions maintained almost normal physiological function of the mandibular gland throughout the perfusion period of 60 min, since the salivary Na+ and K+ concentrations were kept at almost constant levels, comparable with those reported in vivo, and the salivary flow, pH and protein level were also stabilized. Under fixed stimulation conditions with 1 microM ACh or 10 microM pilocarpine, the perfusate PA concentration ranging from 20 to 100 micrograms/ml did not affect the S/E ratio (approximately 0.3). There was a negative correlation between the S/E ratio and salivary pH when stimulated with 0.1 to 10 microM ACh. However, Matin's equation [S. B. Matin et al., Clin. Pharmac. Ther. 16, 1052 (1974)] employing venous effluent and salivary pH values did not explain fully these observed ratios. In contrast, Borzelleca's model [J. F. Borzelleca and J. W. Putney, J. Pharmac. exp. Ther. 174, 527 (1970)] for salivary drug transport using intracellular pH of the mandibular gland cells predicted S/E ratios relatively close to the observed values when the gland was perfused at pH 7.4 or 8.0.

Acetylcholine↗

Ventricular septal perforation following acute myocardial infarction in a patient with hypothyroidism--a case report.

A 61-year-old woman with profound hypothyroidism underwent surgery for a ventricular septal perforation 15 days following an acute myocardial infarction, with no preoperative thyroid replacement. Her immediate postoperative course was complicated by a low cardiac output, respiratory suppression and high output renal failure, requiring prolonged hemodynamic and respiratory support. Thyroid replacement (50 micrograms of thyronine and 100 micrograms of thyroxine daily) was given in two installments on the 2nd day after the operation. The effect of the inotropic agents increased gradually and the patient was weaned off intra-aortic balloon pumping. A large quantity of diuretics, hydration and hyperalimentation also successfully reduced her elevated BUN and serum creatinine. After full thyroid replacement, she was discharged in good health on the 40th postoperative day.

Female↗

Influence of the ipsilateral hemisphere upon somatosensory evoked potential in cats.

Somatosensory evoked potentials (SEPs) were recorded on the skull corresponding to the (left) SI area by (right) superficial radial nerve stimulation. Amongst the various components of the SEP, special attention was directed to the negative component (N15) with a latency of approximately 15 ms. Changes in this potential followed by conditioning stimulation of the ipsilateral (right) hemisphere were observed and the following results were obtained: (i) when conditioning stimuli were applied to the contralateral (left) superficial radial nerve, the ipsilateral (right) thalamic VPL nucleus and the ipsilateral (right) sensory cortex, the amplitude of N15 decreased to 65-80% of the control level at C-T intervals less than 100 ms and (ii) following functional elimination of the unilateral sensory cortex by KCl application, the amplitude of N15 recorded at the opposite side significantly increased. In this condition, the inhibitory effects of the ipsilateral thalamus and contralateral peripheral nerve disappeared. From these observations, ipsilateral homologous cortex may well have an inhibitory influence upon the near field potential (N15) of the SEP.

Animals↗

Postirradiation protection of chromosomes by linoleate.

Physiological concentrations of linoleate reduce the frequency of micronuclei and chromosome aberrations in mouse bone marrow cells in vivo and of micronuclei in human lymphocytes in vitro when administered one hour after exposure of the cells to gamma rays.

Animals↗

Age-dependent pulmonary first-pass elimination of propranolol in rats.

Plasma levels of propranolol after 2.5 mg kg-1 given i.v. and i.a. have been compared in 3- to 4-week-old rats to evaluate the effect of age on pulmonary first-pass elimination of the drug. In 5- to 52-week-old rats, the area under the plasma concentration-time curve (AUC) after an intra-arterial dose was always larger than that after the i.v. dose. The plasma elimination half-lives after both routes of administration were almost identical, but tended to increase with age between weeks 7 and 104. First-pass pulmonary clearance and extraction ratio tended to decrease with age between weeks 7 and 52.

Aging↗

Enhanced bioavailability of morphine after rectal administration in rats.

Plasma morphine levels and the area under the plasma concentration-time curve (AUC) after i.v. (10 mg kg-1), p.o. (100 mg kg-1) and rectal (unrestricted or restricted to 1.5 cm from the anus, 10 mg kg-1) administration of morphine hydrochloride were determined in 10 or 11-week-old male Wistar rats to compare bioavailability of morphine after the rectal dosage with that after oral administration. The AUC value after oral administration (15 micrograms min mL-1), which was normalized by the dose, was only one-tenth of that after i.v. dosing (151 micrograms min mL-1). In contrast, the AUC after rectal administration (unrestricted, 133 micrograms min mL-1; restricted, 142 micrograms min mL-1) was almost comparable with that after i.v. administration. From the comparison of these AUC values, the extent of systemic availability of morphine after rectal (unrestricted or restricted) and p.o. administration was estimated to be approximately 90 and 10%, respectively.

Administration, Oral↗

Propranolol uptake with high capacity by rat perfused lung.

Lung isolated from 7-week-old rats was perfused with pH 7.4 Krebs-Ringer bicarbonate buffer solution (35 mL) containing 1 to 100 micrograms mL-1 of propranolol and 3% BSA at the recirculation rate of 8 mL min-1. Almost parallel bi-exponential drug concentration-time curves were obtained at the initial load lower than 10 micrograms mL-1, whereas relatively slow, mono-exponential decline was found after perfusion at 100 micrograms mL-1. Pharmacokinetic analysis for the perfusate propranolol concentration-time curves when loaded at 1 to 10 micrograms mL-1 yielded almost comparable values for the pulmonary perfusion clearance (0.387 +/- 0.092 to 0.486 +/- 0.095 mL min-1 g-1). In contrast, this parameter was significantly reduced at 100 micrograms mL-1 (0.113 +/- 0.042 mL min-1 g-1). The present findings suggest a trend towards saturation kinetics in the in-vitro pulmonary clearance of propranolol.

Animals↗

Salivary excretion of 5-fluorouracil. II. Fluctuation of saliva/plasma concentration ratio and salivary clearance during a constant rate intravenous infusion in beagle dogs.

Salivary excretion of 5-fluorouracil (5-FU) was investigated during constant rate intravenous infusion (0.306 mg/kg/min) in three male beagle dogs. Parotid (Pr) and mandibular-sublingual (MS) saliva were collected separately by stimulating salivation with 10% citric acid. After the start of 5-FU infusion, plasma and salivary 5-FU concentration increased rapidly to approach their steady state levels. There was a significant correlation between each saliva and plasma 5-FU concentration (p less than 0.01). The saliva/plasma drug concentration ratio (S/P ratio) and salivary pH were significantly higher in Pr than in MS saliva (p less than 0.001), similar to the results following bolus intravenous administration of 5-FU in beagle dogs. Both S/P ratio and salivary clearance increased with time before steady state. Thereafter, these values approached almost constant levels and their fluctuations became smaller than those following the bolus intravenous administration. These results showing S/P ratio and salivary clearance of 5-FU were affected by the plasma drug concentration, suggested the possibility that non-linear pharmacokinetics may be involved in the salivary excretion of 5-FU.

Animals↗