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Biomedical subjects

Y Kuyama

Publications and source records attributed to Y Kuyama.

At least 19 recordsLinked to original sources
PubMed2000

Pancreatic arteriovenous malformation presenting as cysts: Doppler sonographic diagnosis.

A 50-year-old man presented with multiple lesions resembling cysts throughout the pancreas on gray-scale sonography. Pulsatile blood flow detected within the lesions on color Doppler sonography led to the diagnosis of pancreatic arteriovenous malformation (PAVM). Most previously reported PAVMs have been described as having a poorly defined, reticular, or mosaic-like hypoechoic appearance on gray-scale sonography; the cystic appearance of the PAVM seen in our case is unusual.

Arteriovenous Malformations↗
PubMed2000

Use of salivary acetaminophen concentration to assess gastric emptying rate of liquids.

The gastric emptying rate (GER) of liquids can be quantified by calculating the rate of acetaminophen absorption from serial plasma concentrations. As acetaminophen concentrations in saliva are well correlated with those in plasma, the salivary concentrations may be suitable for use in GER measurement. To evaluate such suitability, salivary and plasma samples were simultaneously obtained from seven healthy volunteers at 0, 0.25, 0.5, 0.75, 1.0, 1.5, and 2.0 h after they had ingested 20 mg/kg of acetaminophen mixed with a 200-ml liquid meal (200 kcal). Commonly used parameters for the rate of acetaminophen absorption were calculated from the salivary and plasma data, including the maximum concentration (Cmax), the time to Cmax (t(max)), the concentration at 0.75 h (C0.75), the area under the curve from 0 to 1.0 h (AUC1.0), and the AUC(0.5)/AUC(2.0) ratio. The mean (SD) salivary/plasma concentration ratio was 2.48 (1.47) at 0.25 h, and the means were almost unity afterwards. Significant correlations between saliva and plasma were found in all parameters studied (r = 0.77-0.90; P < 0.05). However, except for t(max), the salivary parameters overestimated those of plasma. The present results suggest that: (1) the salivary acetaminophen concentration at 0.25 h (C0.25) is a poor reflection of plasma C0.25 (2) thereby the parameters embodying salivary C0.25 such as AUC1.0 and the AUC0.5/AUC2.0 ratio, are unreliable, and (3) liquid GER can be assessed by salivary t(max) with minimal distress to the patient.

Acetaminophen↗
PubMed1999

Pharmacokinetic interaction between acetaminophen and lansoprazole.

Because of its minimal gastric toxicity, acetaminophen is the analgesic of choice for patients with gastric acid-related disorders. Because proton pump inhibitors are widely used, concomitant prescription of acetaminophen and lansoprazole would be prevalent. This crossover study was conducted to investigate an acetaminophen-lansoprazole interaction. On one occasion, each of six healthy, fasted, male volunteers ingested 1.0 g acetaminophen dissolved in 200 mL water. On another occasion, at least 1 week apart, 30 mg lansoprazole was administered orally, simultaneously with acetaminophen, after pretreatment with the same dose of lansoprazole once daily for 2 days. Plasma acetaminophen concentrations were measured at 0, 0.25, 0.5, 0.75, 1, 2, 3, 5, and 8 hours after dosing. The peak plasma concentration of acetaminophen and the time to its occurrence were significantly higher and shorter, respectively, during the lansoprazole session than during the control session. Neither the elimination half-life nor the area under the curve was significantly different between the two sessions. Lansoprazole hastens the absorption of acetaminophen solution, but little modifies its elimination rate and bioavailability.

2-Pyridinylmethylsulfinylbenzimidazoles↗
PubMed1999

Pharmacokinetic characteristics of minocycline in debilitated elderly patients.

A pharmacokinetic study of minocycline was performed in 12 debilitated elderly patients who had suffered from acute bacterial respiratory infections. Serial intravenous administrations of 100 mg minocycline were performed at least 10 times (infused for 1 hour, every 12 hours). Blood samples were obtained at 0, 1, 3, and 10 hours after initiating the first and fifth dose and 1 hour after the ninth dose (total, 9 points). The serum concentrations of unchanged minocycline were measured using high-performance liquid chromatography. The obtained data were analyzed using a two-compartment model in 11 cases and a one-compartment model in 1 case. Other clinical data were also collected simultaneously. The mean age of the subjects was 82 +/- 6 years. The elimination half-lives at beta-phase averaged 25.0 +/- 16.4 hours, the volume of distribution averaged 32.9 +/- 13.4 L, and the total clearance averaged 1.14 +/- 0.49 L/h. The correlation coefficient between the expected trough concentration of minocycline in steady-state and the dose per 1 kg body weight was.54 (P =.06), suggesting that dosage should be adjusted by body weight when administered to debilitated elderly patients. The present data are considered to be important and clinically useful because little information is available concerning the pharmacokinetics of minocycline in elderly patients.

Aged↗
PubMed1998

Guide for judicious use of the paracetamol absorption technique in a study of gastric emptying rate of liquids.

The paracetamol absorption technique, a widely used method for evaluating the gastric emptying rate of liquids, appears to be performed inappropriately, resulting from a lack of consideration of pharmacokinetics in paracetamol absorption. This review suggests that appropriate study designs and logical choice of the parameters for the rate of paracetamol absorption are the cornerstone of reliable investigation of gastric emptying using the paracetamol method.

Acetaminophen↗
PubMed1998

Spontaneous intramural hematoma localized in the proximal esophagus: truly "spontaneous"?

After a usual meal, a 57-year-old woman with normal hemostasis experienced a hematoemesis. She was then diagnosed endoscopically as having an intramural hematoma of the esophagus, which ranged from 18 cm to 24 cm from the incisors. The hematoma is considered to have developed not "spontaneously" but as a result of direct abrasive trauma by foodstuffs. The authors think it appropriate to use the term "spontaneous" only when the development of hematoma is unrelated to emetogenic events, impaired hemostasis, and food-induced injury.

Esophageal Diseases↗
PubMed1998

No difference in seroprevalences of Helicobacter pylori infection between patients with pulmonary tuberculosis and those without.

A previous article reported a possible relationship between a history of tuberculosis and Helicobacter pylori infection. Epidemiologic similarities exist between the two infections: Mycobacterium tuberculosis and H. pylori are transmitted from person to person and the risk of acquiring them is elevated in underprivileged environment. This study was conducted to investigate the relationship between the two infections. Serum concentrations of anti-H. pylori IgG antibody were measured in 40 tuberculosis inpatients on antituberculosis chemotherapy for no more than 3 months (group I; 52.4 +/- 21.4 years of age), 43 tuberculosis inpatients on it for more than 3 months (group II; 57.3 +/- 16.3 years), and 60 nontuberculosis outpatients (control subjects; 55.9 +/- 16.7 years). H. pylori seropositivities were similar among control subjects (73.3%), group I (65%), and group II (69.8%). The difference in the antibody concentrations was significant between control subjects and group I (353.7 +/- 321.2 vs. 176.5 +/- 197.9 U/ml) but was not significant between control subjects and group II (353.7 +/- 321.2 vs. 229.9 +/- 249.5 U/ml). The seroprevalences may not be different between patients with pulmonary tuberculosis and those without, and antituberculosis therapy may not decrease the antibody concentrations.

Adolescent↗
PubMed1998

Changes in biliary excretory mechanisms in rats with ethinyloestradiol-induced cholestasis.

Several excretory pathways for cholephilic compounds have been known. To examine the changes in excretory pathways in cholestasis induced by ethinyloestradiol, various bile acids, organic anions and organic cations were intravenously administered to ethinyloestradiol-treated rats and their biliary excretion was studied. Biliary excretion of taurocholate was slightly delayed, but its excretory maximum was markedly decreased. Biliary excretion of lithocholate-3-O-glucuronide, leukotriene C4, sulphobromophthalein and pravastatin was markedly impaired to a similar extent. Biliary excretion of vinblastine, a P-glycoprotein substrate, was increased, suggesting increased expression of P-glycoprotein. In contrast, biliary excretion of erythromycin, a cationic antibiotic, was markedly impaired. In conclusion, ethinyloestradiol treatment altered the biliary excretion of organic compounds, which may partly be related to changes of the canalicular transporters.

Animals↗
PubMed1998

Pharmacokinetic characteristics of cisapride in elderly patients.

We demonstrated pharmacokinetic characteristics of cisapride in elderly patients (85+/-6 years) who had suffered from constipation based on intestinal motility dysfunction. After a single p.o. dose of 2.5 mg cisapride tablet on the first day, plasma unchanged cisapride concentrations were detected at 9 points within 24 hours, using high-performance liquid chromatography method. Subsequently, the patients were treated with cisapride 3 times daily during next 26 days (from the day 2 to the day 27). On the 28th day, a cisapride tablet was given once in the morning and blood samples were obtained with the same procedure as that on day 1. The obtained elimination half-life averaged 21.8+/-10.6 hours, which seems to be considerably longer than those previously reported. The area under the time-concentration curve (AUC) on the day 28 was 2.7 times larger than AUC on the day 1, suggesting that plasma cisapride concentrations can become higher than expected by physicians when given 3 times daily to extremely elderly patients. Because cisapride sometimes induces fatal ventricular arrhythmias and sudden death in a concentration-dependent manner, this medicine should be administered once or twice per day to such patients.

Administration, Oral↗
PubMed1997

Intestinal Behçet's disease associated with non-Hodgkin's lymphoma.

A 45-year-old man with intestinal Behçet's disease noticed an enlarged right cervical lymph node, and was diagnosed with diffuse large cell type, non-Hodgkin's lymphoma. The intrapelvic lymph tract was markedly deformed because of recurrent ileocecal ulceration, and conventional lymphoscintigraphy with a common tracer did not abolish the suspicion that lymphoma cells may have invaded the lymph nodes. Dynamic lymphoscintigraphy with a new tracer, 99mtechnetium-diethylene triamine pentaacetic acid-human serum albumin, because of its high detection sensitivity, was very useful for excluding this suspicion, and for determining the clinical stage of lymphoma. Combination induction chemotherapy led to complete remission without any adverse effects, but subsequent supportive therapy with same protocol could not be completed because of progression of the intestinal lesions. Special management for the intestinal lesions, such as bowel rest, may be essential with chemotherapy for patients with intestinal Behçet's disease.

Antineoplastic Combined Chemotherapy Protocols↗
PubMed1997

Absorption of unconjugated bile acids and tauroursodeoxycholate in the rat intestine.

The absorption of ursodeoxycholate and its tauro-conjugate by the jejunum and the terminal ileum of rat intestine was compared with that of other unconjugated bile acids and taurocholate. In the ligated jejunum, the efficacy of absorption of unconjugated bile acids was in the following order: ursodeoxycholate = deoxycholate > chenodeoxycholate = cholate > lithocholate. This order cannot be explained by the theory that the passive diffusion of bile acids is faster the less hydroxyl bonds in the molecule. These findings on the unconjugated bile acids in the ligated jejunum were further confirmed by perfusion experiments. In the ligated terminal ileum, ursodeoxycholate, cholate and deoxycholate were absorbed as fast as taurocholate or tauroursodeoxycholate, whereas absorption of chenodeoxycholate was significantly slower. The Na+-dependency of the absorption of ursodeoxycholate and cholate in the terminal ileum was confirmed by perfusion studies. In conclusion, intestinal absorption of ursodeoxycholate was efficient in both the jejunum and ileum and these results may contribute to the high availability of ursodeoxycholate in various hepatobiliary diseases.

Animals↗
PubMed1997

Gastrointestinal stromal tumor of the stomach.

We report a case of gastrointestinal stromal tumor (GIST) of the stomach. The patient was a 79-year-old woman with two gastric submucosal tumors detected by ultrasonography. Proximal gastrectomy was carried out and the tumors were diagnosed as GIST by histological and immunohistochemical investigations. Mesenchymal tumors of the gastrointestinal tract have been traditionally regarded as largely leiomyomatous lesions. However, GIST and other tumors have been distinguished recently on the basis of tumor cell differentiation shown by immunohistochemical studies. We discuss the concept and the immunohistochemical characteristics of GIST.

Actins↗