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Biomedical subjects

T Miyahara

Publications and source records attributed to T Miyahara.

At least 91 records · Page 5Linked to original sources
PubMed1997

Endothelin-1 selectively contracts portal vein through both ETA and ETB receptors in isolated rabbit liver.

We determined the constrictive effects of endothelin (ET)-1 on the hepatic vascular resistance distribution and the receptor subtype responsible for the effect in isolated rabbit livers perfused via the portal vein with 5% albumin-Krebs solution. The sinusoidal pressure was estimated using the double vascular occlusion pressure. The basal portal venous resistance comprised 59% of the total portal-hepatic venous resistance. In response to a bolus injection of ET-1 (0.05-5 micrograms), which led to a final concentration of 0.1-10 nM in the recirculating perfusate, the portal venous resistance increased in a dose-dependent manner, whereas the hepatic venous resistance did not change significantly at any concentration. This hepatic vasoconstriction was associated with liver weight loss. The selective portal venous constriction induced by ET-1 was confirmed in livers perfused retrogradely from the hepatic vein to the portal vein. The ET-1-induced hepatic vasoconstriction was significantly attenuated by the selective ETA receptor antagonist BQ-123 (1 microM). The ETB receptor antagonist BQ-788 (1 microM) also attenuated the constriction at ET-1 concentrations less than 10 nM. The combination of BQ-123 and BQ-788 tended to inhibit the hepatic vasoconstriction more effectively than BQ-123 alone. These results suggest that ET-1 selectively constricts the portal vein via both ETA and ETB receptors, with predominance of ETA receptor in isolated albumin-Krebs-perfused rabbit livers.

Animals↗
PubMed1997

Role of circulating blood components and thromboxane in anaphylactic vasoconstriction in isolated canine lungs.

We determined the roles of circulating blood components and chemical mediators in anaphylactic vasoconstriction and microvascular permeability during Ascaris suum antigen-induced anaphylaxis in isolated canine lungs. Either the right or left lower lobe served as the control lung, which was perfused with autologous blood, and the contralateral lobe from the same dog was examined for the effect of albumin Krebs-Henseleit solution (Krebs) or of blockers of various vasoconstrictors with blood perfusion. Pulmonary vasoconstriction occurred after injection of the antigen (15 mg) in both the blood- and Krebs-perfused lungs. However, the percent change of peak pulmonary vascular resistance in the Krebs-perfused lungs tended to be greater than that in the blood-perfused lungs (689.9 +/- 289.3 and 389.3 +/- 171.9%, respectively). This increased peak pulmonary vascular resistance was attenuated similarly by pretreatment with indomethacin (1.1 x 10(-4) M; cyclooxygenase inhibitor), AA-2414 (10(-5) M; thromboxane-receptor antagonist), or a combination of TCV-309 (10(-5) M; platelet-activating factor-receptor antagonist), diphenhydramine (1.7 x 10(-4) M, histamine H1-receptor antagonist), and indomethacin but not by pretreatment with TCV-309 or diphenhydramine alone. The filtration coefficient, an index of vascular permeability, did not change significantly at 15 or 60 min after the antigen in all groups. These findings suggest that anaphylactic vasoconstriction in the isolated canine lung is independent of circulating blood components. Thromboxane is the major mediator for the anaphylactic vasoconstriction. Anaphylaxis does not increase pulmonary vascular permeability in isolated canine lungs.

Anaphylaxis↗
PubMed1997

A polymorphism observed in the experimentally successful peptide vaccine sequence derived from Theileria sergenti piroplasm major surface antigen (p33).

A polymorphism in the experimentally successful peptide vaccine sequence (EVVWKEKKEVKDLDA, amino acids 134-148) derived from the 33 kDa piroplasm major surface antigen (p33) of Theileria sergenti was examined. The vaccine sequences obtained by PCR amplification and sequencing of the p33 gene from a total of 15 parasite-infected cattle blood samples collected from 4 prefectures through Hokkaido to Kumamoto revealed the two major sequences (Ikeda and Chitose stock types) either of which was identified in all samples. Since the peptide vaccine develops the parasite species- or stock-specific immunity in the animals, an application of the two major peptide sequences as cocktailed vaccine should be evaluated for a practical use of this strategy to controlling T. sergenti infection in Japan.

Amino Acid Sequence↗
PubMed1997

[Clinical efficacy of imipenem/cilastatin sodium for respiratory infections in patients with lung cancer].

Imipenem/cilastatin sodium (IPM/CS) was administered to 102 patients with respiratory tract infections and lung cancer. Patients with other serious diseases were excluded and a total of 73 patients were enrolled. They were divided into 12 patients who underwent surgery (operated group) and 61 who did not (non-operated group); the latter group included 28 patients treated with anticancer agents or radiation therapy (treated group) and 33 untreated patients (untreated group). IPM/CS was effective in 75% of the patients, both with and without surgery. The drug was effective in 81% of the treated group, although many of the patients had Stage III or more advanced cancer, as well as bronchial occlusion. IPM/CS was also effective in 69% of the untreated group, although many of the patients have serious infections and a PS (Performance Status) of 3 or greater. Thus, IPM/CS treatment achieved good results. Bacteriological studies showed that 3 out of 4 strains in the operated group and 16 out of 18 in the non-operated group were eliminated. Safety was evaluated in all patients. Two patients (2%) experienced side effects and two others (2%) showed abnormal clinical findings, but the symptoms were mild and resolved after discontinuation or completion of therapy. In conclusion, IPM/CS was very effective for treating respiratory infections in patients with lung cancer.

Adenocarcinoma↗
PubMed1997

[Does physical status influence the axillary temperature among junior high-school students?].

The relationship between physical status and axillary temperature was examined in 373 junior high-school students. Axillary temperature was measured with a mercury glass thermometer, twice a day (8:15, 15:45) for a week, 10 minutes taken for each measurement. In addition, body mass index (BMI) was calculated from weight and height. And the subjects were divided into two groups according to the mean value of BMI (19.20 [kg/m2]), i.e., the low BMI group (LB) and the high BMI group (HB). We then compared the axillary temperature between LB and HB. The temperature both in the morning and afternoon was significantly lower in the HB than in the LB (p < 0.01, p < 0.05). In conclusion, a high BMI was associated with a decrease in axillary temperature in junior high-school students.

Adolescent↗
PubMed1997

A case of successfully treated giardiasis in pancreas.

We report a case of giardiasis in the pancreas in a patient with diabetes mellitus. The patient is interesting in the following: 1) Giardia lamblia was found only in the pancreas and not in the gall bladder by cytology on endoscopic retrograde cholangiopancreaticography (ERCP) and by cerulein-secretin test (CST). 2) ERCP revealed multiple small cysts scattered throughout the pancreas. 3) Decreased pancreatic exocrine function was recovered by treatment with metronidazole.

Aged↗
PubMed1996

Photoelectron holography of the si(001) surface.

Three-dimensional images of the near-surface atom arrangement were calculated from two-dimensional photoelectron diffraction data by several imaging algorithms: (i) a basic method with a Fourier transformation at one kinetic energy over k space, considering the phase factor due to the path-length difference; (ii) energy summation of the above results; (iii) Fourier transformation within small k-space windows; and (iv) their combinations. Atomic images produced by these methods from the experimental Si 2p photoelectron diffraction patterns of an Si(001) surface are compared with the crystal geometry. The results show that the energy-summed small-window method, called SWEEP, gives the best images.

Journal Article↗
PubMed1996

Participation of nitric oxide in the sympathetic response to anaphylactic hypotension in anesthetized dogs.

The role of nitric oxide (NO) was determined using a NO synthase inhibitor, NG-nitro-L-arginine methyl ester (L-NAME; 20 mg/kg bolus and 0.05 mg/kg per min) in the renal sympathetic and hypotensive response to systemic anaphylaxis induced by Ascaris suum antigen (10 mg, i.v.) in naturally sensitized anesthetized dogs. Renal nerve activity (RNA) in animals pretreated with D-NAME, the biologically inactive enantiomer (n = 7), showed an initial increase (192 +/- 32%, (mean +/- SE) followed by a decrease (61 +/- 14%) after antigen. Pretreatment with L-NAME (n = 7) did not affect the initial sympathoexcitation but abolished the secondary sympathoinhibition (110 +/- 13%). However, the depressor response to antigen was not different between the L-NAME and D-NAME groups (-87 +/- 13 mmHg and -84 +/- 12 mmHg). In conclusion, NO is involved in the anaphylaxis-induced renal sympathoinhibitory response but not hypotension in anesthetized dogs.

Animals↗
PubMed1996

Effects on cultured neonatal mouse calvaria of the flavonoids isolated from Boerhaavia repens.

A MeOH extract from the whole plant of Boerhaavia repens was found to inhibit bone resorption induced by parathyroid hormone (PTH) in tissue culture. Systematic separation of the MeOH extract afforded one new and two known flavonoid glycosides, namely, eupalitin 3-O-beta-D-galactopyranosyl-(1-->2)-beta-D-glucopyranoside (1), eupalitin 3-O-beta-D-galactopyranoside (2), and 6-methoxykaempferol 3-O-beta-D-(1-->6)-robinoside (3). The structure of the new compound 1 was determined using spectroscopic techniques. The inhibitory activity of these substances toward bone resorption induced by PTH was evaluated, and compounds 1 and 2 were found to exhibit significant activity.

Animals↗
PubMed1996

Case report: mucin-producing cystic neoplasm of the pancreas with onset in childhood.

Mucin-producing tumours of the pancreas have been recently reported with increasing frequency and most cases have occurred in middle-aged and elderly people. In the present report, a case of a 21-year-old man with mucinous cystadenoma of the pancreas is reported. He had a long history of recurrent pancreatitis from the age of 8. When he was aged 10, the first branch of the main pancreatic duct was shown to be enlarged on endoscopic retrograde pancreaticography (ERP). A series of ERP studies and computed tomography scans performed over a period of 11 years demonstrated continuing growth of this enlargement of the pancreatic duct. Pancreaticoduodenectomy was performed and the patient has been well without further episodes of acute pancreatitis and has been free of recurrent tumour for 1 year.

Adult↗
PubMed1996

Development of a potassium-specific adsorbent for direct hemoperfusion.

Direct hemoperfusion (DHP) over an exchange resin for sodium is capable of rapidly lowering an elevated serum potassium level but has not been used clinically because of subsequent electrolyte abnormalities. After the completion of detailed in vitro studies, we developed a sodium/calcium/magnesium exchange resin mixture specifically to remove potassium from the blood. The mixture, which consisted of exchange resins for sodium (48%), calcium (48%), and magnesium (4%), gave the most satisfactory results in vitro. DHP through these resin-mixture columns for 2 h reduced elevated plasma potassium levels (6.7 +/- 1.1 to 3.5 +/- 0.6 mEq/L, p < 0.001) in anephric dogs without including any significant change in the levels of sodium, calcium, magnesium, albumin, total protein, or cholesterol. The platelet losses and changes in the plasma free hemoglobin levels observed were similar to those found with activated charcoal hemoperfusion. These results suggest that this resin hemoperfusion may be useful in patients with acute hyperkalemia.

Animals↗
PubMed1996

Modulation of human soleus H reflex in association with voluntary clenching of the teeth.

1. To determine the effects of motor activity in the jaw on more general motor behavior, we examined the modulation of the soleus H reflex in association with voluntary clenching of the teeth in healthy adult volunteers. 2. The amplitude of the H reflex increased remarkably during teeth clenching. The increase during maximal teeth clenching was greater than that induced either by maximal voluntary isometric contraction of the wrist extensors or by maximal voluntary clenching of the fists. 3. The increase in amplitude of the soleus H reflex showed a positive correlation with the strength of teeth clenching, as monitored by recording electromyographic (EMG) activity from the masseter muscle. 4. The increase in amplitude of the H reflex associated with teeth clenching started before the onset of the EMG activity of the masseter muscle, reached a peak shortly after the onset, and then declined to a plateau that continued in parallel with the masseter EMG until the end of teeth clenching. 5. The increase in amplitude of the H reflex in association with teeth clenching was partially decreased during the inhibitory masseteric reflex evoked by innocuous electrical stimulation of the lip. 6. It is concluded that the soleus H reflex is facilitated in association with voluntary teeth clenching, and that descending influences from the cerebral cortex, as well as peripheral afferent impulses from the oral-facial region, are involved in this facilitation. It is proposed that oral motor activity can exert strong influences on the motor activity of the other parts of the body.

Adult↗
PubMed1996

Acute hypoxic pulmonary vascular response does not accompany plasma endothelin-1 elevation in subjects susceptible to high altitude pulmonary edema.

We have previously shown that high altitude pulmonary edema-susceptible subjects (HAPE-S) have an accentuated pulmonary vascular response to hypoxia. In this study, we investigated the relationship between plasma endothelin-1 (ET-1) levels and the acute hypoxic pulmonary vascular response in HAPE-S and control subjects. In six HAPE-S and seven healthy subjects, we evaluated acceleration time/right ventricular ejection time (AcT/RVET) using Doppler echocardiography, and measured plasma ET-1 levels by radioimmunoassay (RIA) before and after 5 minutes of breathing 10% oxygen. The HAPE-S showed a significantly increased pulmonary vascular response to hypoxia compared with healthy subjects. However, no statistically significant changes of plasma ET-1 levels were observed before and after hypoxia in both groups. We conclude that the increased pulmonary vascular response to acute hypoxia in HAPE-S may not be related to ET-1 release.

Acute Disease↗
PubMed1996

Effects of muscle relaxation therapy using specially designed plates in patients with pulmonary emphysema.

It has been suggested that respiratory muscle dysfunction plays a major role in the development of acute ventilatory failure in patients with chronic obstructive pulmonary disease (COPD). In this study, we devised a respiratory muscle relaxation maneuver using wedge-shaped wooden plates, with which pressure was exerted on the intercostal and accessory respiratory muscles by hand, or by tapping with a wooden hammer, for 15-20 minutes twice a day. The muscle relaxation maneuver was performed in 5 moderate to severe pulmonary emphysema patients for 4 weeks and in 7 emphysema patients for 6 weeks, and the effects on pulmonary function were examined. After the therapy, inspiratory capacity (IC) and vital capacity (VC) in both the 4 weeks-and 6 weeks-treated groups, and the forced expiratory volume in 1 second (FEV 1.0) in the 6 weeks-treated group were significantly increased, and CO2 retention had also improved. Daily peak expiratory flow (PEF) showed significant increases from 2 weeks after the initiation of the therapy. These results suggest that the respiratory muscle relaxation maneuver is effective for improving the pulmonary function of pulmonary emphysema patients.

Aged↗