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Biomedical subjects

T Hara

Publications and source records attributed to T Hara.

At least 361 records · Page 20Linked to original sources
PubMed1999

Potentiation of vancomycin-induced histamine release by muscle relaxants and morphine in rats.

The intravenous injection of vancomycin sometimes causes anaphylactoid reactions, in which histamine release may play a major role. These reactions are more frequently manifested when vancomycin is injected into anesthetized patients. We examined the vancomycin-induced histamine release and the interaction of vancomycin with muscle relaxants or opioid in rats. In an in vitro study with rat peritoneal mast cells, treatment with vancomycin at concentrations of greater than 1.25 mM produced significant histamine release. Tubocurarine, vecuronium, pancuronium, succinylcholine, and morphine up to concentrations of 0.25, 1, 5, 30, and 5 mM, respectively, produced no significant histamine release. However, the nonsignificant histamine release induced by 0.5 mM vancomycin was clearly enhanced by combining vancomycin with any of these agents. In the in vivo study, the intravenous injection of vancomycin significantly increased the plasma histamine levels in rats when vancomycin was injected at 200 mg/kg of body weight (63.2 +/- 34.0 ng/ml [mean +/- standard deviation]) but not when it was injected at 100 mg/kg (30.8 +/- 20.2 ng/ml) compared with that in the saline-treated rats (22.5 +/- 11.4 ng/ml). Although the subcutaneous administration of morphine (10 mg/kg) never increased the plasma histamine levels, the intravenous injection of vancomycin (100 mg/kg) 30 min after this morphine treatment markedly increased the plasma histamine levels (56.0 +/- 26.9 ng/ml). These findings provide experimental evidence that the combination of muscle relaxants or an opioid with vancomycin may increase the risk of anaphylactoid reactions by enhancing the release of histamine.

Animals↗
PubMed1999

Hypotension induced by exercise is associated with enhanced release of adenyl purines from aged rat artery.

To determine whether the antihypertensive effects of exercise are associated with release of ATP and its metabolites from arteries, we assayed blood pressure and the release of adenine nucleotides and nucleosides from the caudal arteries of exercised and sedentary aged hypercholesterolemic rats. Exercise on a treadmill for 12 wk significantly decreased the rise in systolic and diastolic blood pressure by 7.5 and 15.9%, respectively, with advanced age. The concentrations of oleic, linoleic, and linolenic acids in the caudal artery decreased significantly with exercise, demonstrating an association between exercise and the unsaturation index of caudal arterial fatty acids. The amounts of total adenyl purines released by the arterial segments from exercised rats, both spontaneously and in response to norepinephrine, were significantly greater by 80.0 and 60.7%, respectively, than those released by tissues from sedentary rats. These results suggest that exercise alters the membrane fatty acid composition in aged rats as well as the release of ATP from vascular endothelial cells and that these factors are associated with the regression of the rise in blood pressure normally observed with advanced age.

Adenine Nucleotides↗
PubMed1999

Thyrotropin regulates c-Jun N-terminal kinase (JNK) activity through two distinct signal pathways in human thyroid cells.

c-Jun N-terminal kinases (JNK) participate in cellular responses to mitogenic stimuli and environmental stresses. We investigated whether and how TSH, which promotes the proliferation and differentiation of thyroid cells, regulates JNK activity in primary cultured human thyroid cells. TSH stimulated JNK activity in cytosolic fractions of thyroid cells measured by in vitro kinase assay. A low concentration of TSH (10(-11) M) stimulated JNK activity but at a higher dose (10(-8)-10(-7) M), TSH suppressed JNK activity without any change of JNK protein level. Activation of JNK by TSH was also observed in CHO cells stably transfected with TSH receptor complementary DNA (cDNA), suggesting a ligand-receptor specific interaction. TSH stimulated JNK activity through a pertussis toxin-sensitive pathway. We next elucidated the signal transduction pathways in TSH-induced JNK activation by examining the involvement of four distinct intracellular signal molecules; protein kinase C (PKC), cAMP, Ca2+, and PI3-kinase. The stimulation of JNK by TSH was blocked by two PKC inhibitors and suppressed by 8-bromo-cAMP or forskolin. These findings demonstrate that TSH regulates JNK activity biphasically in human thyroid cells through an interaction between Gi-PKC and cAMP-PKA pathways.

8-Bromo Cyclic Adenosine Monophosphate↗
PubMed1999

Stereoselective pharmacokinetics of RS-8359, a selective and reversible inhibitor of A-type monoamine oxidase, in rats, mice, dogs, and monkeys.

RS-8359, (+/-)-4-(4-cyanoanilino)-5,6-dihydro-7-hydroxy-7H-cyclopenta[d]-py rimidine, inhibits, selectively and reversely, A-type monoamine oxidase (MAO-A). In order to clarify the stereoselective metabolism of this drug, plasma concentrations of the [R] and [S]-enantiomers of RS-8359 were determined by chiral column HPLC after oral administration of each enantiomer to rats, mice, dogs, and monkeys. After administration of the [R]-enantiomer, high levels were retained in all animal species studied. On the other hand, when the [S]-enantiomer was administered, plasma concentrations decreased rapidly in rats and mice, and extremely rapidly in dogs, while in monkeys, only a trace amount was detected immediately after dosing. Thus, it was found, as a common phenomenon in rats, mice, dogs, and monkeys, that plasma concentrations of the [S]-enantiomer were markedly lower than those of the [R]-enantiomer. Secondly, the [R]-enantiomer was observed in plasma after administration of the [S]-enantiomer, and the [S] to [R] chiral inversion rate was estimated from AUC([R] after [S])/AUC([R] after [R]). The percentage was 45.8% in rats, 3.8% in mice, 0.8% in dogs, and 4.2% in monkeys. Further, the [S]-enantiomer was detected in plasma of SD rats dosed with the [R]-enantiomer, suggesting [R] to [S] chiral inversion in rats. These results show marked species differences in the chiral inversion of the cyclopentanol group of RS-8359. A mechanism of chiral inversion is discussed based on experiments using isolated rat hepatocytes.

Animals↗
PubMed1999

Single- and double-strand breaks in solid pBR322 DNA induced by ultrasoft X-rays at photon energies of 388, 435 and 573 eV.

We measured strand breaks of pBR322 plasmid DNA irradiated with ultrasoft X-rays using monochromatic synchrotron radiation as a light source. Three photon energies, 388, 435 and 573 eV, a value below and above the nitrogen K-edge and above the oxygen K-edge, respectively, were chosen for the irradiation experiments as they have an equivalent photon transmittance of the sample. Irradiated DNA was analyzed by agarose gel electrophoresis and the numbers of single- and double-strand breaks (ssb and dsb) were determined by measuring the band intensity on the gel after ethidium bromide staining. The action cross-sections for the ssb and dsb slightly increased with the photon energy. The ratio between 388 and 573 eV was about 1.5 for both forms of strand breaks. The absorbed energy required for a strand break was about 60 eV for ssb and 1 keV for dsb, less than one fifth of the values obtained previously in the 2 keV region. On the other hand, the absorbed energies per strand break, as well as the ratio of the action cross-section for the ssb to that for the dsb, were constant regardless of the photon energy used. The K-shell photoabsorption on carbon, nitrogen and oxygen atoms in the DNA molecule, followed by an Auger cascade, induced DNA strand breaks with a constant efficiency in terms of the absorbed energy. These results indicate that the strand breaks of the DNA molecule in the solid state are mainly caused by the photo- and Auger-electrons and the efficiency of the strand breaks little depends on the atoms ejecting these secondary electrons.

DNA↗
PubMed1999

A simple hydroponic culture method for the development of a highly viable root system in Arabidopsis thaliana.

In the studies of nutritional absorption and metal toxicity in the root, it is important to grow plants without technical damage. We established a simple hydroponic culture system for Arabidopsis thaliana to obtain a healthy plant having a well-developed root system with many lateral roots. The phytotoxic effects of Cr, Cu, and Al ions were examined by FDA-PI staining using this culture system. The pattern of root inhibition varied with the ion, suggesting the usefulness of this culture system.

Aluminum↗
PubMed1999

The effect of hydroxyapatite coating on the bonding of bone to titanium implants in the femora of ovariectomised rats.

We have studied the effect of hydroxyapatite (HA) coating in 15 ovariectomised and 15 normal rats which had had a sham procedure. Twenty-four weeks after operation, HA-coated implants were inserted into the intramedullary canal of the right femur and uncoated implants into the left femur. The prostheses were removed four weeks after implantation. Twelve specimens in each group had mechanical push-out tests. Sagittal sections of the other three were evaluated by SEM. The bone mineral density (BMD) of the dissected left tibia was measured by dual-energy x-ray absorptiometry. The difference in BMD between the control and ovariectomised tibiae was 35.01 mg/cm2 (95% CI, 26.60 to 43.42). The push-out strength of the HA-coated implants was higher than that of the uncoated implants in both groups (p < 0.0001), but the HA-coated implants of the ovariectomised group had a reduction in push-out strength of 40.3% compared with the control group (p < 0.0001). Our findings suggest that HA-coated implants may improve the fixation of a cementless total hip prosthesis but that the presence of osteoporosis may limit the magnitude of this benefit.

Animals↗
PubMed1999

Long-term effect of growth hormone (GH) treatment on body composition in children with GH deficiency.

OBJECTIVE: It is important for GH-deficient children to treat abnormal body composition associated with a metabolic consequence, not only short stature. In this study we evaluated long-term effects of GH therapy on body composition in GH-deficient boys and girls. SUBJECTS AND METHODS: Forty-nine subjects with GH deficiency, 35 boys and 14 girls, 6 to 14 years of age, were studied. All the subjects were treated for three years with recombinant human GH at a weekly dosage of 0.5 IU/kg by subcutaneous daily injection. Body composition was measured by bioelectrical impedance analysis (BIA 101, Spectrum II 287, RJL Systems, Detroit, Mich). RESULTS: Body fat (%) decreased significantly during the first three months of GH treatment. These values were maintained low thereafter in boys, in contrast to those which continued to tend upward in girls from the second year of the treatment. Lean body mass (kg) increased significantly with increasing extracellular water (kg) and body cell mass (kg) in both sexes during GH treatment. CONCLUSION: Our data demonstrate that GH can reduce body fat mass in GH-deficient boys and girls. The gender difference in changes in body fat with age during the course of this study is compatible with that observed in normal children. The rapid increase in extracellular water and the gradual increase in body cell mass both contributed to the steady increase in LBM during GH treatment.

Adipose Tissue↗
PubMed1999

Biclonal lymphoplasmacytic immunocytoma associated with Crohn's disease.

A 33-year-old man with a 4-year history of Crohn's disease presented with marked ascites and an abdominal tumor. Two M-protein peaks, immunoglobulin (Ig) G-kappa and IgA-kappa, were detected in the serum. Neoplastic lymphoplasmacytic cells were infiltrated in the bone marrow and ascites. Histological examination of the abdominal tumor showed marked proliferation of lymphoplasmacytic cells that were positive for either IgG or IgA. Moreover, DNA sequences of the expressed IgG and IgA genes were different in the complementarity-determining region 3. These results suggest that chronic inflammation in Crohn's disease contributes to the simultaneous development of biclonal lymphoplasmacytic immunocytoma of the small intestine.

Abdominal Neoplasms↗
PubMed1999

[Interstitial pneumonitis associated with Sweet's syndrome in the elderly].

Sweet's syndrome occurring during the course of interstitial pneumonitis in a 70-year-old woman was encountered. She was admitted because of dyspnea on exercise, dry cough and interstitial shadow on chest x-ray. Lung biopsy, together with other findings confirmed interstitial pneumonitis. Five days after admission, genital ulcer and aphtha on the oral mucosa were detected and exudative erythema appeared on her right shoulder, chest and back. Histological examination of the skin lesions demonstrated numerous nutrophilic infiltration in the upper dermis, indicating Sweet's syndrome. The skin eruption rapidly disappeared on treatment with colchicine. Although six months after admission interstitial pneumonitis caused respiratory failure, treatment with prednisolone and cyclophosphamide was effective. Serological and immunological tests demonstrated hyper-gammaglobulinemia and positive reaction for anti SS-A antibody. Pathological examination of the lip revealed numerous lymphocyte infiltrates around the duct of the minor salivary gland, suggesting Sjögren's syndrome as the background disease of Sweet's syndrome and interstitial pneumonitis. This evidence indicating that even in elderly patients, skin lesions of Sweet's syndrome may reveal the background disease.

Aged↗
PubMed1999

Factors affecting water balance and fecal moisture content in suckling calves given dry feed.

Holstein bull calves were used to examine factors affecting water balance and fecal moisture content in suckling calves given dry feed for 2 wk from 1 wk of age. In Experiment 1 (n = 16), the shift of water balance (decreased urine volume, and increased water retention and fecal water excretion) and elevation of fecal moisture content were greatest when calf starter and Sudangrass hay were fed in addition to liquid milk replacer, compared with calves receiving only milk replacer. Intermediate changes occurred when calves were fed milk replacer and calf starter or milk replacer, calf starter, and rice straw. Water retention was correlated positively with digestible DMI and negatively with urine volume. Fecal water excretion was highly correlated with fecal DM excretion. In Experiment 2 (n = 18), water balance and fecal moisture content during wk 2 were affected by free access to calf starter and hay from wk 1. Urine volume of calves fed dry feed and milk replacer was lower than that of calves fed only milk replacer; however, when water was available in addition to dry feed, urine volume was similar to that of calves fed only milk replacer. Fecal water excretion was highly correlated with water retention rather than with fecal DM excretion, suggesting a close relationship to extracellular fluid volume. Ruminal fermentation would be an important factor affecting both water balance and fecal moisture content in suckling calves given dry feed.

Animal Feed↗
PubMed1999

[Clinical analysis of parotid cancer].

A clinical study was performed on 42 patients with parotid cancers initially treated in our hospital from 1972 to 1997. The five-year cumulative survival rate was 69% in the whole group and 72% in the radical surgical treatment group (n = 40). The five-year survival rates according to stage were as follows: stage I, 95% (21); stage II, 75% (4); stage III, 0% (1); and stage IV, 37% (16). The factors influencing prognosis were cases of T3 and T4 (p < 0.05), stage III and IV (p < 0.01), and cervical lymph node metastasis (p < 0.01). Regarding treatment modalities, a partial parotidectomy appeared to be a curable surgical procedure for T1 cases. However, a lobectomy is recommended for T2 cases. Furthermore our study proposed that prophylactic supraomohyoid neck dissection should be necessary for mucoepidermoid carcinoma (high-grade malignancy) and undifferentiated carcinoma of T4N0 cases.

Adult↗
PubMed1999

[Dermoid cyst with thyroid follicle perforated into bladder and ileum: a case report].

A 64-year-old woman was admitted to our hospital on August 19, 1996 with the chief complaint of microscopichematuria. A solid mass was found in her lower abdomen. An abdominal CT scan suggested a large intrapelvic cystic mass and the existence of a fistulous connection between the mass and the small intestine. The existence of a fistula was confirmed by a preoperative barium enema and a cystscopic study. On September 25, 1996, a suprapubic partial cystectomy and total hysterectomy were performed since an intrapelvic abscess was suspected. The cystic mass was observed to adhere to the hollow viscus (uterus, rectum, appendix, ileum and bladder). As a result a part of the ileum and bladder were also removed with the mass. The contents of the cyst included a foul smelling gas and white-green pus. Using a probe, we found two fistulous openings to the ileum and bladder. The histopathological findings indicated a dermoid cyst of the left ovary with thyroid follicles, which are known as "Struma ovarii".

Abscess↗
PubMed1999

[The effect of calories of preoperative oral intake on the glucose metabolic response in children].

We performed prospective study to determine whether the increase of calories with preoperative oral intake will prevent ketosis due to preoperative starvation in children receiving afternoon surgery. Twenty five children (aged 3 to 9 years) for elective minor surgery under general anesthesia with sevoflurane and nitrous oxide were divided into morning surgery group and afternoon surgery group, and the latter was divided into 2 groups according to calories contained in the clear fluid. The calorie of the clear fluid in the afternoon group P was 0.24 kcal.ml-1, and that in the afternoon group A was 0.48 kcal.ml-1. The calorie of the clear fluid in the morning group was 0.48 kcal. ml-1. The levels of blood glucose, blood ketone body, plasma free fatty acids (NEFA), insulin, glucagon and cortisol were measured before and during intravenous infusion in three groups. The urinary catecholamine excretion was measured in the urine collected from 18:00 on the day before operation day until the start of anesthesia. There were no significant differences in the levels of blood glucose, NEFA, insulin, glucagon, cortisol and urinary catecholamine excretion. But the level of blood ketone body only in the afternoon group P was significantly higher than that in the morning group. But the levels of NEFA before infusion were higher than average in 40-60 percent of patients of each group. These data suggest that the increasing preoperative calories with oral intake will prevent ketosis due to preoperative starvation in the afternoon group as well as in the morning group. But the short duration of starvation only can not prevent lipolysis completely.

Blood Glucose↗