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Biomedical subjects

K Iwakiri

Publications and source records attributed to K Iwakiri.

At least 19 recordsLinked to original sources
PubMed2001

Glomangiopericytoma causing oncogenic osteomalacia. A case report with immunohistochemical analysis.

A 47-year-old woman suffered from gait disturbance due to back pain and muscle weakness. Laboratory data showed serum hypophosphatemia, elevated alkaline phosphatase, and a normal level of ionized calcium. Radiological examinations revealed multiple pathologic fractures in the ribs and pubic rami. She had had no episode of familial or any other notable disorder, and so she was initially treated with medication for adult-onset osteomalacia. However, 19 years later (when she was 66 years old), she noticed a soft-tissue tumor in her buttock. The tumor was excised. The histological features were those of glomangiopericytoma characterized by both glomus tumor-like and hemangiopericytoma-like structures. After removal of the tumor, her symptoms disappeared immediately. Laboratory data normalized 8 months later. To our knowledge, this is the first report of oncogenic osteomalacia caused by glomangiopericytoma.

Aged↗
PubMed2001

Relationship between severity of reflux esophagitis according to the Los Angeles classification and esophageal motility.

PURPOSE: We investigated the relationship between the severity of reflux esophagitis (RE) according to the Los Angeles (LA) classification and esophageal motility. METHODS: We examined 28 healthy subjects (HS) and 48 RE patients (grade A of the LA classification, 16 patients; grade B, 16 patients; grade C or D, 16 patients). Esophageal manometry was performed by the intraluminal microtransducer method. Resting lower esophageal sphincter (LES) pressure was assessed by the rapid pull-through method. Esophageal contraction after ten repeated 5-ml water swallowings separated by 30-s intervals was measured at 3, 8, 13, and 18 cm above the LES. RESULTS: The resting LES pressure and the amplitude of esophageal contraction 3 cm above the LES in the grades C + D group were significantly lower than those in the HS group. The amplitude of esophageal contraction 3 cm above the LES in the grade B group was significantly lower than those in the grade A group and the HS group. The frequency of failed peristalsis in the grades C + D group was significantly higher than that in the HS group and the grade A and grade B groups. CONCLUSIONS: The present findings suggested that the severity of RE according to the LA classification would be likely to mainly reflect esophageal volume clearance.

Case-Control Studies↗
PubMed2000

Effect of nifedipine administration (10 mg) on esophageal acid exposure time.

The effect of nifedipine administration (10 mg) on esophageal acid exposure time was investigated in 11 non-reflux esophagitis (non-RE) patients and 11 grade C (Los Angeles classification) reflux esophagitis (RE) patients. In each subject, esophageal pH monitoring was performed, with the subject in the supine position, preprandially (1 h) and 3-h postprandially after oral administration of a placebo in the morning and oral administration of nifedipine (10 mg) in the afternoon on the same day. In the non-RE patients, there was no difference in the esophageal acid exposure time between administration of the placebo and that of nifedipine. In patients with RE, the esophageal acid exposure time after the administration of nifedipine was significantly (P<0.05) longer than that after the placebo. In patients with severe RE, the severity of RE may worsen with nifedipine administration.

Aged↗
PubMed1999

Comparison of the electrostatic binding sites on the surface of ferredoxin for two ferredoxin-dependent enzymes, ferredoxin-NADP(+) reductase and sulfite reductase.

Plant-type ferredoxin (Fd), a [2Fe-2S] iron-sulfur protein, functions as an one-electron donor to Fd-NADP(+) reductase (FNR) or sulfite reductase (SiR), interacting electrostatically with them. In order to understand the protein-protein interaction between Fd and these two different enzymes, 10 acidic surface residues in maize Fd (isoform III), Asp-27, Glu-30, Asp-58, Asp-61, Asp-66/Asp-67, Glu-71/Glu-72, Asp-85, and Glu-93, were substituted with the corresponding amide residues by site-directed mutagenesis. The redox potentials of the mutated Fds were not markedly changed, except for E93Q, the redox potential of which was more positive by 67 mV than that of the wild type. Kinetic experiments showed that the mutations at Asp-66/Asp-67 and Glu-93 significantly affected electron transfer to the two enzymes. Interestingly, D66N/D67N was less efficient in the reaction with FNR than E93Q, whereas this relationship was reversed in the reaction with SiR. The static interaction of the mutant Fds with each the two enzymes was analyzed by gel filtration of a mixture of Fd and each enzyme, and by affinity chromatography on Fd-immobilized resins. The contributions of Asp-66/Asp-67 and Glu-93 were found to be most important for the binding to FNR and SiR, respectively, in accordance with the kinetic data. These results allowed us to map the acidic regions of Fd required for electron transfer and for binding to FNR and SiR and demonstrate that the interaction sites for the two enzymes are at least partly distinct.

Arabidopsis Proteins↗
PubMed1999

Effect of body position on lower esophageal sphincter pressure.

This study examined the effect of body position on lower esophageal sphincter (LES) pressure. In 36 healthy subjects and 31 patients with reflux esophagitis, LES and intragastric pressures were measured with subjects in the supine and sitting positions by the intraluminal microtransducer method. LES pressure was significantly lower in the sitting position than in the supine position in both healthy subjects and patients with reflux esophagitis. Intragastric pressure was significantly higher in the sitting position than in the supine position in both healthy subjects and patients with reflux esophagitis, but this increase was less marked than the decrease in LES pressure in the sitting position. The overlap of LES pressure values between healthy subjects and patients with reflux esophagitis was lower in the sitting position than in the supine position. We conclude that the measurement of LES pressure in the sitting position reflects LES function more accurately.

Adult↗
PubMed1998

Effects of body position and liquid meal ingestion on esophageal acid exposure time in healthy subjects.

We investigated the effect of body position and ingestion of a test liquid meal on esophageal acid exposure time in 20 asymptomatic healthy subjects. Intraesophageal pH monitoring was performed for 1 h before meals and 3h postprandially with the subject in the supine (n = 10) or sitting position (n = 10). The test meal had a total volume of 800 ml and an energy content of 500 kcal. Esophageal acid exposure time was defined as the percentage of time at pH < 4.0. There was no difference in preprandial or postprandial esophageal acid exposure time between the supine and sitting positions. Esophageal acid exposure time for the 3-h postprandial period was significantly greater than that for the preprandial period in both the supine and the sitting positions. The difference in body position did not influence preprandial or postprandial esophageal acid exposure time, but ingestion of the liquid meal significantly increased the esophageal acid exposure time in both the supine and sitting positions in asymptomatic healthy subjects.

Eating↗
PubMed1998

Effects of transjugular intrahepatic portosystemic shunt (TIPS) on esophageal motor function and gastroesophageal reflux.

The effects of transjugular intrahepatic portosystemic shunt (TIPS) placement on esophageal motor function and gastroesophageal reflux were investigated in patients with esophageal varices. In six men with esophageal varices, esophageal manometry and upper gastrointestinal endoscopy were performed before and 15-20 days after TIPS placement. Intraesophageal pH monitoring was performed in the four patients with severe esophageal varices (defined as the largest sized varices) following TIPS placement. Findings were compared with those in six healthy men (controls) who underwent esophageal manometry and intraesophageal pH monitoring. The esophageal varices resolved or were reduced after TIPS placement. Resting lower esophageal sphincter (LES) pressures were similar in the study group before and after TIPS placement and in the control subjects. The incidence and progression of esophageal contractions were similar in the study group before and after TIPS placement and in the control subjects. At 3 cm above the LES, the amplitude of esophageal contraction after TIPS placement was significantly higher than that before TIPS placement. At 3 and 8 cm above the LES, the amplitude of esophageal contraction in the control subjects was significantly higher than that in the study group before and after TIPS placement. Esophageal acid exposure time after TIPS placement was similar to that in the controls. TIPS placement is a useful treatment that improves esophageal motor function without the occurrence of pathologic gastroesophageal reflux.

Esophageal and Gastric Varices↗
PubMed1997

Herbal medicine-associated lead intoxication.

A female patient visited our hospital with abdominal pain and anemia. Examination for a gastrointestinal disease gave no diagnostic information. Laboratory studies of the parameters of heme biosynthesis revealed an enzymatic inhibition by lead. The diagnosis of lead poisoning was confirmed by detection of an elevated blood lead level. Excessive lead ingestion was thought to be caused by herbal medicines and/or by an earthen teapot.

Abdominal Pain↗
PubMed1996

Relationship between postprandial esophageal acid exposure and meal volume and fat content.

The effect of meal volume and fat content on gastroesophageal reflux was investigated in 20 asymptomatic healthy subjects. In each subject, intraesophageal pH monitoring was performed during a 3-hr postprandial period (PP) in the same position (supine or upright) on two successive days. On day 1, 500-ml low- and high-fat meals were ingested and, on day 2, an 800-ml low-fat meal was ingested. The acid exposure time was assessed as the percentage of time with a pH < 4.0. The acid exposure time in subjects in the upright position was significantly longer in the 800-ml group than in the 500-ml group for the entire PP (2.7 +/- 1.5%; mean +/- SE, 0.7 +/- 0.4%; P < 0.05). Of subjects in the supine position, the high-fat group showed significantly longer acid exposure time than the low-fat group both for the entire PP (7.6 +/- 3.0%, 0.7 +/- 0.5%; p < 0.05) and for the second hour (P < 0.05). We have demonstrated that differences in the meal volume and fat content influence gastroesophageal reflux in healthy asymptomatic subjects and that this influence varies with the position.

Dietary Fats↗
PubMed1993

Gastroesophageal reflux and esophageal motility in patients with esophageal varies.

Gastroesophageal reflux (GER) and esophageal motility were evaluated in patients with esophageal varices (EV). This study comprised 35 patients with EV, 18 patients with reflux esophagitis (RE) and 12 healthy volunteers. EV were classified according to the F factor by the Endoscopic Classification of EV of the Japanese Research Society for Portal Hypertension. The lower esophageal sphincter (LES) function in the F3 group was significantly decreased and similar to that in the RE group. The amplitude of primary peristalsis at the site of F2 or F3 EV was significantly decreased. Acid clearance was significantly delayed in the F2 and F3 groups compared to that in the healthy subjects. GER was suppressed by the presence of F3 EV and was significantly decreased in this group compared to that in the healthy subjects. An antireflux barrier is concluded to be maintained in patients with F3 EV.

Esophageal and Gastric Varices↗
PubMed1992

[A case of paraesophageal bronchogenic cyst with esophageal communication].

A case of mediastinal bronchogenic cyst communicating with the esophagus was reported. Previously, only 2 cases have been reported in the available literature. A 34-year-old man was admitted with a cystic mass communicating with the esophagus which was demonstrated on a barium study. Operation was performed with a suspect of esophageal diverticulum or congenital cyst with esophageal communication. At right thoracotomy, a mass measuring 6.0 x 5.0 cm with a well-defined patent communication to the esophagus was resected. It was a monolocular cyst containing a small amount of viscous mucus. Histologically, the cyst lined by a ciliated columnar epithelium, and it was diagnosed as a bronchogenic cyst because of the presence of the mucous glands, smooth muscle tissue and cartilage. This is the first case report of mediastinal bronchogenic cyst with esophageal communication appeared in the Japanese literature.

Adult↗