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Biomedical subjects

K Obayashi

Publications and source records attributed to K Obayashi.

At least 55 records · Page 3Linked to original sources
PubMed1997

Does tyrosine kinase modulate delayed-rectifier K channels in guinea pig ventricular cells?

Phosphorylation by tyrosine kinases has been shown to promote cellular growth and hypertrophy and to play a key role in modulating ion channels. We have examined possible effects of genistein, a protein tyrosine kinase (PTK) inhibitor, on cardiac delayed-rectifier K currents (IK). Guinea pig ventricular myocytes were voltage-clamped by conventional whole-cell mode (5.4 mM [K]out/150 mM [K]in; pCa = 8; 36 degrees C). Amplitudes of tail and steady-state (2-s pulse) currents were measured as IK. Micromolar concentrations of genistein (10-100 microM) reversibly inhibited basal, swelling-enhanced (by 70% hypotonic solution), and intrapipette Cyclic adenosine monophosphate (cAMP) (1 mM)-enhanced IK concentration-dependently, while intrapipette cAMP-enhanced IK were also affected by daidzein, an inactive analog of genistein. In contrast, lavendustin A (10 microM) and tyrphostin 51 (100 microM), other types of PTK inhibitors, had no effect on IK. These results suggest that genistein may inhibit IK and that this inhibition is not mediated by an inhibition of tyrosine kinase activity.

Animals↗
PubMed1997

[Analysis of in-field and marginal relapse in stage I/II non-Hodgkin's lymphoma treated with radiotherapy].

One hundred sixty-three patients with previously untreated stage I/II non-Hodgkin's lymphoma were analyzed as to their in-field and marginal relapse of the irradiated field following treatment with more than 30 Gy of radiotherapy between 1981 and 1995 at Hyogo Medical Center for Adults. Local regrowth in case of partial response was counted as in-field relapse. Complete response was obtained in 94.5% of the cases at the termination of radiotherapy and in 98.8% finally. The ten-year cumulative in-field relapse and marginal relapse rates were 5% and 8.7%, respectively. The cumulative in-field relapse rate (CIFRR) in cases of bulky disease (more than 5 cm in largest diameter of the tumor) was significantly higher than in those of non-bulky disease (26.1% in 8 years vs 2.4% in 10 years, P < 0.01). The radiation dosage delivered (40 Gy = < and 50 Gy > vs 50 Gy < =) a great much difference in cases of bulky disease (23.8% for 8-year CIFRR vs 0% for 1-year CIFRR, respectively), but less difference with non-bulky disease (2.6% vs 2.2%). High LDH and suboptimal dose chemotherapy (three courses and less chemotherapy containing ADM or its derivatives, chemotherapy without ADM or no chemotherapy) had a negative impact on marginal control in aggressive lymphoma. Extended field setting in aggressive lymphoma was not proven to be beneficial in comparison with involved field setting as to marginal field relapse. Thus, it is concluded that (1) higher doses should be given to bulky disease, (2) careful field coverage with enough margin is recommended for aggressive lymphoma with high LDH or treated without optimal dose chemotherapy, and (3) extended field setting is not necessary.

Adolescent↗
PubMed1996

Autonomic dysfunction and anemia in neurologic disorders.

The effect of autonomic dysfunctions on anemia in various neurological disorders, such as familial amyloidotic polyneuropathy (FAP) Type I, pandysautonomia, and Shy-Drager syndrome was examined. As a control, hemograms of patients with amyotrophic lateral sclerosis (ALS), which is known to be free from autonomic dysfunction, was compared with patients with the above neurological disorders. FAP and pandysautonomia patients showed significant anemia comparable with the severity of the autonomic dysfunctions. Shy-Drager patients exhibited mild anemia. However, in ALS patients, no such anemia was recognized at all even in the end stage of this disease. In pandysautonomia patients, hypoplastic bone marrow was recognized, which was quite consistent with the data previously reported in FAP patients. Human recombinant erythropoietin improved orthostatic hypotension as well as anemia in 4 FAP patients. These results suggest that autonomic dysfunction may be deeply connected with erythropoiesis.

Adult↗
PubMed1996

Hormonal regulation of cardiac cystic fibrosis transmembrane conductance regulator chloride channels.

The chloride conductance that arises from the stimulation of beta-adrenoceptors has been shown to be carried by a cardiac isoform of cystic fibrosis transmembrane conductance regulator (CFTR) Cl- channels. This brief review will focus first upon the cellular signal transduction system for the activation of this type of Cl- channels and then its regulation by catecholamines, muscarinic agonists, endothelin-1 and angiotensin-II. Both in physiological and pathological conditions, the complex interaction of these agonists modulates the Cl- conductance, which is potentially arrhythmogenic by shortening the action potential duration and inducing the depolarization.

Action Potentials↗
PubMed1995

[A case of transient ischemic attacks preceded by postprandial hypotension].

A 78-year-old man with a history of total gastrectomy, myocardial infarction and hypertension was admitted to our hospital because of frequent transient attacks of consciousness disturbance, aphasia and right hemiparesis after meals. His attacks occurred one to three times a day, 30 to 60 minutes after meals and lasted 120 to 180 minutes. At the time of the attacks his blood pressure decreased, but his pulse rate did not change. Cerebral angiography demonstrated atherosclerotic occlusion of the left internal carotid artery. There was no myocardial uptake of 123I-metaiodobenzylguanidine (MIBG). These results suggest that our patient had an autonomic dysfunction. Duplex carotid ultrasonography revealed that the blood flow velocity fell about 30% at the time of the attacks. His autonomic dysfunction and major artery occlusion may have produced a hemodynamic TIA following postprandial hypotension.

Aged↗
PubMed1993

[Radiotherapy for vulvar cancer].

Fifteen patients who had primary vulvar cancer treated with radiotherapy as an initial treatment at Hyogo Medical Center for Adults and Hyogo Cancer Center from January 1971 to December 1990 are presented. Two patients were stage 0, one stage I, three stage II and nine stage III. Nine patients received electron irradiation with or without interstitial irradiation and intracavitary vaginal irradiation. Five patients received megavoltage X-ray irradiation using AP/PA parallel opposed fields including the pelvic nodes and perineum followed by boost irradiation of electrons, interstitial irradiation and intracavitary vaginal irradiation. The total dose delivered to the primary tumor ranged from 50 to 100 Gy (73 Gy on average). The actuarial 5-year survival rate of the patients was 43.6%. Complete regression (CR) was achieved in 60% of the patients. However, CR was not achieved in any of five patients with palpable inguinal nodes. In contrast, all the patients who had tumors of less than 2 cm in diameter achieved CR. Five of nine CR cases relapsed. First sites of failure were vagina, groin and vulvar region. Recurrence occurred more than four years after treatment in three cases. Necrosis occurred in five of nine CR cases.

Adult↗
PubMed1991

Caries susceptibility in inbred mouse strains and inheritance patterns in F1 and backcross (N2) progeny from strains with high and low caries susceptibility.

We studied dental caries susceptibility in various inbred mice strains infected with Streptococcus mutans and the inheritance pattern in the F1 and the N2 backcross animals. A high caries score was observed in four laboratory strains, BALB/cAJcl, C57BL/6NJcl, C57BL/10Slc and DBA/2NJcl. Three strains, C3H/HeNJcl, AKR/JSlc and CBA/JNCrj, showed less caries. Males of strain C57BL/10Slc (mean caries score = 112.2) and females of strain C3H/HeNJcl (mean caries score = 24.0) were chosen for examinations of the inheritance of the caries susceptibility. The mean caries score in (C57BL/10Slc x C3H/HeNJcl) F1 hybrids was 98.4, demonstrating that F1 progenies were susceptible. A number of N2 mice were obtained by mating the F1 male and the C3H/HeNJcl female. The caries scores of these N2 male mice had an extensive range, from 14 to 194. Assuming that a caries score over 74 (median of the scores between C57BL/10Slc and C3H/HeNJcl) belonged to the highly caries-susceptible group, N2 mice could be divided into groups with low or high caries susceptibility. Furthermore, the effect of nu/nu mutation on caries susceptibility in mice was also examined.

Analysis of Variance↗
PubMed1991

[Small sized non-small cell lung cancer in advanced stage].

Eighteen cases of non-small cell, small sized advanced lung cancer, out of 362 operated cases for 6 years excluding 7 cases of small cell lung cancer, 60 of preoperative treated and 27 of inoperable cases, were discussed. A small sized tumor was defined as a tumor within 8,000 mm3 in its volume, calculated by multipling three lengths measured on the resected specimens. There were fourteen cases with stage 3 and 4 (A), and four cases with N1 disease (B). In group A, three cases of twelve with N2 diseases showed the tiny skipping lesion in the mediastinum with negative regional nodes. Remaining two had a lesion of dissemination and pulmonary metastasis. In group B, they showed unusual way of N1 spread, in which two of them with left upper lobectomy had metastatic lymph nodes on the non-bearing lobe, the lower lobe, and other two cases took regional lymph nodes metastasis without invasive growth of the main tumor. Predominant histologic type was adenocarcinoma, but the subtype and the differentiation of it were not specific. The level of CEA was low below 5 ng/dl in most of them except three cases, in which it suggested massive positive nodes and pulmonary metastasis. Seven patients died of the disease in two years. Remainders are alive, 4 with and 7 free from the tumor with the longest period of 3 years and a half. N2 diseases of small sized tumor were found in the cases with the volume of 3 cm3 and more at almost same ratio.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1990

[Clinical evaluation of radiotherapy for endocrine ophthalmopathy].

Ten patients with severe endocrine ophthalmopathy were treated by radiotherapy at Hyogo Medical Center for Adults from May 1984 to February 1988. All but one of the patients had poorly responded to previous systemic or topical corticosteroid therapy. The target of the radiotherapy was both retrobulbar tissues. The radiation field used was about 4 x 4 cm, excluding the pituitary gland and the brain, and was angled 5 degrees posteriorly to avoid the contralateral lens. A total of 2000 cGy was given to each patient over a 2 week-period. Eight of the ten patients showed some response, with 5 of them (50%) having a good to excellent response. Treatment was more effective for soft tissue changes, proptosis and keratopathy, while myopathy was less responsive. As for the duration of the eye signs and symptoms, those of a shorter duration (less then 12 months) responded better. It was also noted that the degree of the eye muscle enlargement on the pre-treatment orbital CT scan was directly correlated to the results of the treatment. Although three of the patients experienced transient headache, there were no serious acute reactions or long term complications. In conclusion, retrobulbar radiotherapy is a well-tolerated, safe and effective treatment for severe endocrine ophthalmopathy.

Adult↗
PubMed1990

[Clinical evaluation of sodium alginate on oral mucositis associated with radiotherapy].

We evaluated the effect of sodium alginate on 39 patients with oral mucositis associated with radiotherapy. Sodium alginate was administered during radiotherapy to 17 patients with head and neck cancer. Compared with 22 patients without administration, sodium alginate reduced the pain and the erosion of oral mucosa significantly. Consequently the interval of radiotherapy was shortened. It is, therefore, expected that the effect of radiotherapy improves by the administration of sodium alginate.

Adult↗
PubMed1983

Unloading effects of molsidomine on peripheral circulation and cardiac hemodynamics in patients with acute myocardial infarction.

The unloading mechanisms and side of peripheral action of the new antianginal drug molsidomine was compared with isosorbide dinitrate (ISDN) in 14 patients with acute myocardial infarction using a Swan-Ganz catheter and venous occlusion plethysmography. Sublingual molsidomine (2-4 mg) increased calf venous capacitance (CVC) (0.42 +/- 0.18 to 0.64 +/- 0.09 ml/100 ml, p less than 0.05) from 30 to 240 minutes, while simultaneously lowering of PCWP (25.9 +/- 4.9 to 15.8 +/- 7.3 mmHg, p less than 0.05) and CVP (9.3 +/- 3.7 to 5.8 +/- 3.5 cmH2O, p less than 0.05). Calf blood flow (CBF), calf vascular resistance (CVR), CI, TSPR and SWI were not affected significantly. Molsidomine reduced preload more than 240 minutes after its administration. Sublingual ISDN increased CBF into the initial 15 minutes (1.19 +/- 0.49 to 1.83 +/- 0.98 ml/100ml/min, p less than 0.05) and CVC from 5 to 60 minutes (0.42 +/- 0.19 to 0.68 +/- 0.24 ml/100ml p less than 0.01) while simultaneously lowering PCWP (24.3 +/- 2.2 to 14.6 +/- 4.5 mmHg, p less than 0.01) and CVP (9.0 +/- 2.8 to 5.5 +/- 3.5 cmH2O, p less than 0.05). Neither drug affected cardiac index, blood pressure or systemic vascular resistance. These data suggest that molsidomine significantly lowered elevated preload (PCWP/PCP) by dilating venous capacitance vessels. Its length of action was 240 minutes compared with 60 minutes obtained with ISDN, which suggests this new agent may be of marked benefit in the AMI patients suffering from backward failure uncomplicated by forward failure in whom continued preload reduction is necessary. (Results are expressed as the mean +/- standard deviation).

Adult↗
PubMed1982

Unloading effects of vasodilators on peripheral circulation and cardiac hemodynamics in patients with acute myocardial infarction.

Effects of three representative vasodilators on peripheral and cardiac hemodynamics were studied in 20 patients with heart failure due to acute myocardial infarction (PCWP greater than 18 mmHg, C1 greater than 2.20 L/min/m2) using venous occlusion plethysmography and a Swan-Ganz catheter. Sublingual isosorbide dinitrate (ISDN) significantly increased calf venous capacitance (CVC) from 5 to 60 min (p less than 0.01) and calf blood flow (CBF) in the initial 15 min (p less than 0.05), while simultaneously lowering PCWP (p less than 0.05) and central venous pressure (p less than 0.05). Calf vascular resistance (CVR), cardiac index, blood pressure, and total systemic peripheral resistance (TSPR) were not affected significantly. Nitroglycerin ointment (NGO) significantly decreased CVR (p less than 0.05) and increased CVC (p less than 0.05) from 60 to 240 min, simultaneously with lowering of PCWP (p less than 0.01), central venous pressure (p less than 0.05), and TSPR (p less than 0.05). Oral prazosin (Pz) increased CBF (p less than 0.01) and CVC (p less than 0.05) from 60 to 240 min, simultaneously with significant lowering of PCWP (p less than 0.01) and TSPR (p less than 0.05), resulting in increased stroke work index (p less than 0.05). These data confirm that ISDN predominantly causes capacitance vessel dilatation and reduce excessive venous return, while Pz and NGO dilate not only capacitance vessels but also resistance vessels, consequently reducing systemic vascular resistance and resulting in increased peripheral blood flow and cardiac performance. It was observed that the higher the base-line calf vascular resistance rose, the better the response to the vasodilator treatment appeared in terms of a decrease in calf vascular resistance.

Adult↗