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Biomedical subjects

Y Hirose

Publications and source records attributed to Y Hirose.

At least 397 records · Page 22Linked to original sources

Role of substance P in cough.

The sensory neuropeptide, substance P (SP), is present in human airway nerves, beneath and within the epithelium where the condensed localization of neutral endopeptidase (NEP), the major enzyme degrading SP, is observed. To test the hypothesis whether SP stimulates the cough reflex and NEP modifies the cough reflex, we studied the cough response to various stimuli in awake guinea-pigs. Inhibition of NEP with phosphoramidon caused cough, which was inhibited by systemic capsaicin treatment and by aerosols of a specific NK1 receptor antagonist FK 888. Aerosols of FK 888 also inhibited cough induced by bronchoconstricting agents such as acetylcholine and histamine in non-sensitized animals and by ovalbumin antigen in animals sensitized to ovalbumin. The number of coughs induced by histamine aerosols was inhibited by systemic capsaicin treatment and enhanced by pretreatment with a NEP inhibitor phosphoramidon. Likewise, FK 888 inhibited the augmented cough response to aerosolized capsaicin in female guinea-pigs treated with a long-term medication of an angiotensin-converting enzyme inhibitor, cilazapril. In humans, aerosols of SP did not cause cough in normal subjects, whereas it did in patients with common colds. The SP fragment a major metabolite of SP produced by NEP, was less effective compared with SP in these patients, suggesting that damaged epithelium may facilitate the penetration of SP. These findings suggest that SP released from sensory nerves in response to stimuli may mediate cough and NEP may have a role in modulating SP-induced effects.

Angiotensin-Converting Enzyme Inhibitors↗

Determination of glufosinate ammonium and its metabolite, 3-methylphosphinicopropionic acid, in human serum by gas chromatography-mass spectrometry following mixed-mode solid-phase extraction and t-BDMS derivatization.

A method for the analysis of glufosinate ammonium (GLUF) and its metabolite 3-methylphosphinicopropionic acid (MPPA) in human serum by gas chromatography-mass spectrometry (GC-MS) was developed. Employing a mixed-mode cartridge with both anion exchange action and weak nonpolar interaction, we extracted GLUF and MPPA from the serum and carried out GC-MS analysis of their tert-butyldimethylsilyl derivatives. The detection limits of GLUF and MPPA were 10 pg and 1 pg, respectively. Full mass spectra of 100 pg GLUF and of 10 pg MPPA were easily obtainable. The recovery rate of 90.0+/-11.9% (or better) when the serum concentrations of GLUF and MPPA were 10-0.1 microg/mL. Results of 23 serum samples, from patients with GLUF poisoning, measured by this method correlate well with those derived from the conventional high-performance liquid chromatography method (r = 0.996). The developed GC-MS method is likely to become a useful analytical technique in clinical settings.

Aminobutyrates↗

Multidetector SPECT scanner for brain and body: system performance and applications.

A multidetector whole-body single photon emission computed tomography (SPECT) scanner has been developed for high-resolution dynamic SPECT imaging. The scanner consists of three detector rings with 128 NaI crystals (14 x 26 x 30 mm) in each ring, providing three tomographic images at 30 mm intervals. This system uses a rotation of collimator around the patient combined with the detector rotation for fine data sampling. The in-plane spatial resolution is 14.2 mm (full width of half maximum) with high-resolution (HR) collimator, 22.0 mm with high-sensitivity (HS) collimator, and 10.6 mm with high-resolution brain (HRB) collimator. The axial resolution is 24.0, 34.0, and 23.5 mm with HR, HS, and HRB collimator, respectively. The sensitivity measured with a 20% energy window for 99mTc in a 20 cm diameter phantom is 5.7, 17.0 and 6.6 kcps/muCi/ml with HR, HS, and HRB collimator, respectively. This scanner allows dynamic SPECT imaging both for brain and body organs with good spatial resolution.

Brain↗

A pitfall in ultrafast CT scanning for the detection of left atrial thrombi.

We studied 41 patients with mitral stenosis by ultrafast CT (UFCT) and transesophageal echocardiography to detect left atrial thrombi. Cardiac UFCT was performed twice after contrast medium injection to obtain early (during injection lasting 40-60 s) and late (approximately 5 min after beginning injection) phase images. There were 10 patients (24%) in whom a filling defect detected in the early phase disappeared in the late phase. The site of filling defects was the left atrial appendage in nine patients and the left atrium in one patient. All of the filling defects were in the ventral side of the left atrium. Furthermore, all of those patients had chronic atrial fibrillation. Transesophageal echocardiography revealed no thrombus in the area of the filling defect in the early phase. We believe that blood stasis existed in those patients. This finding leads to a false-positive result when only early phase images are obtained. The diagnosis of thrombi should be made only when a filling defect is observed in both phases. Late phase scanning is necessary in the diagnosis of left atrial thrombi.

Adult↗

Viable but denervated right ventricular myocardium: a case of Eisenmenger reaction.

We report on a 47-year-old woman who experienced an Eisenmenger reaction (mean pulmonary artery pressure: 86 mm Hg) induced by atrial septal defect. Radionuclide myocardial scans with 99mTc-MIBI and 123I-BMIPP showed increased uptake to the right ventricular myocardium, whereas the 123I-MIBG scan disclosed no uptake to the right ventricular myocardium. The scans showed no apparent abnormality in the left ventricular myocardium. These findings suggest that the right ventricular myocardium was viable but denervated due to severe pulmonary hypertension. The mechanism of right ventricular failure may be closely related to sympathetic denervation.

Antihypertensive Agents↗

Hypergammaglobulinemic purpura in patients with Sjögren's syndrome: a report of nine cases and a review of the Japanese literature.

Nine patients with hypergammaglobulinemic purpura associated with primary Sjögren's syndrome were presented. All patients were female (mean age 45.6) and showed recurrent purpura on the lower extremities and typical findings of Sjögren's syndrome with high gammaglobulin and IgG levels, rheumatoid factors, anti-SSA/SSB antibodies (5/5) and anti-nuclear antibodies (6/9). Vasculitis was seen in 6 patients, 4 were of the mononuclear cell type and 2 of the neutrophilic cell type. Six patients had intermediate complexes between 7S and 19S shown by serum ultracentrifugation. Immunofluorescent staining showed immunoglobulin deposition along the blood vessel walls of the skin in these patients. These data suggest that hypergammaglobulinemic purpura in Sjögren's syndrome is vasculitis caused by immunologic processes.

Adult↗

Erythroleukemia and gastric cancer following thorotrast injection.

A 63-year-old male, who had undergone angiography using thorium dioxide (Thorotrast) at the age of 15 for investigation of a giant hemangioma on his left thigh, developed anemia in September 1986 (47 yrs after the angiography). A diagnosis of erythroleukemia was made from a bone marrow study which showed 56.4% megaloblastoid erythroblasts and 12.8% myeloblasts. Autopsy revealed Thorotrast deposition in the liver, spleen, bone marrow, and lymph nodes, and monotonous proliferation of myeloblasts in the bone marrow. He also had differentiated tubular adenocarcinoma of the posterior wall of the stomach.

Adenocarcinoma↗