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Biomedical subjects

K Onishi

Publications and source records attributed to K Onishi.

At least 19 recordsLinked to original sources
PubMed1996

Changes in calcium transient and left ventricular function during positive inotropic stimulation and myocardial ischemia in indo-1-loaded beating guinea pig heart.

To elucidate the issues such as excitation-contraction coupling and myocardial ischemia, it is necessary to measure intracellular free Ca2+ concentration and mechanical function of hearts perfused via the normal arterial circulation. For this purpose, we simultaneously measured Ca(2+)-dependent indo-1 fluorescence and left ventricular (LV) pressure on a beat-to-beat basis in Langendorff guinea-pig hearts, and investigated the changes in Ca2+ transient and LV function during inotropic stimulation and myocardial ischemia. The indo-1 fluoresence ratio and LV developed pressure increased the perfusate [Ca2+] increased from 1.6 to 3.2 mmol/L, and there was a good correlation between Ca2+ transient and LV contractility. Digoxin (10(-6) mol/L) and milrinone (10(-5) mol/L) increased LV contractility with a concomitant increase in Ca2+ transient, and the relative increase of Ca2+ transient produced by milrinone was much more than that by digoxin. The reduction of coronary perfusion pressure from 80 to 40 mm Hg decreased LV contractility with an increase in indo-1 fluorescence ratio. These results suggest that Ca2+ responsiveness of contractile apparatus declines during inotropic stimulation by milrinone and during myocardial ischemia. Thus, this experimental technique is useful to investigate the interrelation of Ca2- regulation and LV function during a variety of pharmacological and physiologic perturbations.

Animals↗
PubMed1996

Blood pressure and its regulation in spontaneously hypertensive rats bred on the lowest sodium diet for normal growth.

To investigate the effects of dietary sodium restriction from conception to adulthood on blood pressure and its regulatory mechanisms, male offspring were derived from inbreeding in spontaneously hypertensive rats fed a diet containing sodium of 175 mumol/g food (control) or 22 mumol/g (low sodium), which is the least sodium content for normal growth. While urinary sodium excretion was markedly less, the low sodium diet did not inhibit body growth and failed to blunt the development of hypertension. Neither plasma catecholamine concentration nor depressor response to hexamethonium was different between the two groups at any age examined (8, 12, and 20 weeks). Plasma renin concentration was not elevated, whereas urinary excretion of aldosterone was increased at any age in the low sodium group compared with that in the control group. Other sets of rats were fed a diet containing sodium of 175 mumol/g plus mefruside (a diuretic) of 0.001% in the same manner as in the other two groups. Urinary sodium excretion per creatinine was higher than in the other groups. The diuretic treatment inhibited body growth and suppressed adult blood pressure. While the sympathetic function was not affected, both plasma renin concentration and urinary excretion of aldosterone were elevated. These results indicate that dietary sodium restriction with the least sodium for normal growth from conception cannot blunt either the sympathetic nervous function or the development of hypertension in spontaneously hypertensive rats. Aldosterone appears to play an important role in maintaining sodium homeostasis under the dietary sodium restriction.

Aldosterone↗
PubMed1996

Calcium sensitization in perfused beating guinea pig heart by a positive inotropic agent MCI-154.

We investigated the effects of MCI-154, a positive inotropic agent that increases the myofilament response to Ca++, on Ca++ transients, left ventricular (LV) function and phosphodiesterase (PDE) III activity of guinea pig heart, and compared them with the effects of pimobendan and milrinone. In Langendorff guinea pig hearts loaded with a fluorescent Ca++ probe indo-1, LV pressure and Ca++ transient were measured simultaneously. MCI-154 (10(-10)-10(-6) M) increased LV developed pressure, +dP/dt and -dP/dt with a reduction of LV end-diastolic pressure, although it did not affect coronary flow. The positive inotropic activity of MCI-154 was more potent than that of pimobendan and milrinone; EC50 values (concentrations for increasing +dP/dt by 50% from base line) were 4.31, 41.5 and 294 x 10(-9) M, respectively. The positive inotropic effect of MCI-154 was accompanied by the increase in systolic, diastolic and amplitude of indo-1 fluorescence ratio. The relative increase in Ca++ transients against the increase in LV contractility produced by MCI-154, however, was significantly less than that by increasing perfusate [Ca++], pimobendan or milrinone. MCI-154 (3 x 10(-7)-10(-4) M) inhibited the activity of PDE III isolated from guinea pig LV tissues, but the inhibitory effect of MCI-154 was less than pimobendan and milrinone; IC50 values were 10.1, 3.5 and 2.4 x 10(-6) M, respectively. These findings suggest that MCI-154 exerts a positive inotropic effect mainly through Ca(++)-sensitizing action in intact beating whole hearts.

Animals↗
PubMed1995

Intra-operative scalp expansion for wound closure without tension in craniosynostosis operation--technical innovation.

Primary scalp wound closure using intra-operative scalp expansion in a craniosynostosis operation is described. Since this method enables easy scalp expansion, it is considered to be a useful adjunctive technique which should be taken into account when closing scalp wounds in craniosynostosis surgery, where the risk exists of cranial expansion-induced compression and deformity of the remodelled bone flaps after bone fixation.

Craniosynostoses↗
PubMed1995

An aspect of sentence processing in Alzheimer's disease: quantifier-noun agreement.

We assessed sentence processing in Alzheimer's disease (AD) with measures of sentence-picture matching, grammaticality judgments of sentences, and sentence completion. The results demonstrated significant and consistent difficulty with a grammatical feature of sentences on all three experiments. This impairment could not be explained by factors such as sentence length, dementia severity, or a short-term memory deficit and was independent of difficulty interpreting the meanings of words. We hypothesize that AD patients are impaired at appreciating the conceptual relations that underlie certain grammatical features of sentences.

Aged↗
PubMed1995

[The association of the disease activity of rheumatoid factor positive vasculitis and the level of rheumatoid factor].

Rheumatoid factor (RF), an autoantibody against the Fc portion of denatured IgG, has long been recognized as an important biologic marker not only for rheumatoid arthritis but also for other auto-immune diseases. In this study, we measured the level of serum RF in four patients with RF positive systemic vasculitis using laser nephelometry. Three patients were diagnosed as polyarteritis nodosa and the other patient was diagnosed as systemic vasculitis without the finding of typical necrotizing vasculitis from biopsies. In the result, we found that the level of RF paralleled the disease activity in these cases. When active phase of the disease, the level of RF showed very high, and after the treatment combined with plasmapheresis, corticosteroid and immunosuppressive agent, the level of RF decreased in accordance with CRP, ESR and clinical features. These suggested that RF was the disease specific marker for RF positive vasculitis and beneficial informations for proper diagnosis and better treatment could be provided by measurement of the level of RF in patients with RF positive systemic vasculitis.

Adult↗
PubMed1995

[The use of TM HAKEN plate in craniofacial surgery].

Rigid internal fixation using mini/micro plate has become a frequent application in cranio-maxillo-facial surgery. In order to make plate fixation easier and reduce operative time, the TM HAKEN plate, a kind of micro plate, was devised which has a thorny HAKEN like an ice pick and applied to cranio-facial surgery. The plate is made of titanium, and th HAKEN and screw are made of titanium alloy. These allow contoured engagement in all three dimensions due to the flexibility of titanium, and firm fixation due to the physical strength of titanium alloy, resulting in minimized artifact on CT scan and MRI images. The fixation is accomplished by just driving in the plate with a hammer, and using screws. In the case of wide operative field, the plate is driven in directly, while in the case of small field, the plate is driven in with an impactor. TM HAKEN plate has been used for osteosynthesis in 39 cases of craniofacial surgery at the Department of Plastic and Reconstructive Surgery of Toho University Hospital between September 1992 and September 1994. Of the 39 cases, 19 were cranioplasty using frozen preserved auto-carvarial bone, 9 were midface fractures, 6 were fixation of free bone grafting, and 5 were fixation of artificial bone (hydroxyapatite-tricalcium phosphate composite ceramics) grafting. Satisfactory results were obtained in all cases without any difficult complications such as infection, exposure or migration. In addition, reliable post-operative evaluations and follow-ups were possible with reduced artifact on CT scan and MRI images.(ABSTRACT TRUNCATED AT 250 WORDS)

Bone Plates↗
PubMed1994

Rapid detection of virus genome from imported dengue fever and dengue hemorrhagic fever patients by direct polymerase chain reaction.

Serum specimens from patients with imported dengue fever and dengue hemorrhagic fever were directly subjected to reverse transcription and polymerase chain reaction (RT-PCR) without any RNA purification. The amplified virus genome was detected within 3 hours. The results of PCR corresponded closely to the results of virus isolation using cultured mosquito cells, suggesting that direct RT-PCR procedure greatly facilitates rapid diagnosis of dengue infection.

Adult↗
PubMed1994

[Immediate breast reconstruction with the transverse rectus abdominis musculocutaneous flap (TRAM-flap)].

The surgical treatment of breast cancer shows a recent trend toward breast-saving procedures, in consideration of quality and body image. Surgeons who performed mastectomy, however, have not taken aggressive approaches to reconstructive surgery, leaving this to plastic surgeons. We adopted the transverse rectus abdominis musculocutaneous flap (TRAM-flap) for breast reconstruction in 1988 and performed immediate breast reconstructions in 37 cases. There were no major complications, and good cosmetic results were obtained. For general surgeons, this excellent technique can safely cope with tissue defects in radical mastectomy, as well as modified radical mastectomy. Immediate breast reconstruction with this technique will be an integral part of breast cancer surgery in company with breast-saving surgery.

Adult↗
PubMed1993

[Reoperation in patients with thymoma].

For past seven years, reoperations were carried out for six patients with thymoma and myasthenia gravis (MG). Of six patients, five patients were suspected recurrent thymoma and remaining one patient was diagnosed as the residual thymus after thymothymectomy or thymomectomy. Myasthenia gravis has been progressing in five patients after initial operation except for one patient. Two cases of pleural dissemination tumors, one case of local recurrent thymoma and one case of the residual thymus were confirmed by surgery, remaining two patients had no recurrent tumor. As surgical procedure, median sternotomy using for reoperation has a great surgical risk, because left brachiocephalic vein closely adhered to the sternum is apt to be injured. Clinical symptoms of MG were improved in all the patients after reoperation regardless of recurrent tumor.

Adult↗
PubMed1993

[Total arch replacement for dissecting aneurysm using permanent bypass to the supra-aortic branches and left-heart bypass].

The patient was a 36-year-old women with Marfan syndrome who had received graft replacement of ascending aorta for Stanford-type A dissecting aneurysm two years ago. She was re-operated on for residual arch and descending aortic dissection. We have found that it was Simple and effective to perform total arch replacement by using permanent bypass to the three principal supra-aortic branches and left-heart bypass.

Adult↗
PubMed1992

Operation for polysyndactyly of the fifth toe using Z-plasty.

A new operative procedure was devised to treat polysyndactyly of the fifth toe. This procedure, which consists of removal of the fifth toe, correction of the alignment of the preserved sixth toe by arthroplasty and construction of an interdigital space by Z-plasty, is technically simple and produces good results, both functionally and aesthetically.

Adolescent↗
PubMed1991

One-stage repair of blepharophimosis.

Congenital blepharophimosis is a congenital anomaly characterized by abnormalities in the area of the eyes, including bilateral ptosis, shortening of the horizontal fissure of the lid, expansion of the intercanthal distance, and epicanthus inversus. The condition is subject to autosomal-dominant heredity and is said to occur more frequently in Orientals than in Occidentals. Over the past 9 years, we have surgically treated 11 cases of congenital blepharophimosis using a procedure in which levator resection and medial canthoplasty are performed in one stage. It has been commonly believed that when levator resection and medial canthoplasty are performed at the same time, tension in the eyelid becomes too strong to achieve favorable results; therefore, the standard procedure has been to divide the operation into two stages. In all 11 cases we experienced, however, it was possible to obtain good results with a single-stage operation.

Child, Preschool↗
PubMed1991

Phase variation of pili of Corynebacterium pilosum.

Whether or not (?) phase variation occurs in the pili of Corynebacterium pilosum was biologically examined using the colony enzyme-linked immunosorbent assay (ELISA) blot test with anti-pili immune serum. From the densely piliated clone (35P+) of C. pilosum 35, non-piliated variants were isolated at a frequency of 2.45 x 10(-3). From one of the non-piliated variants (designated as P(-11)/35P+), a piliated variant was isolated at a frequency of 4.68 x 10(-4), one log less frequently than the non-piliated variant. From this piliated variant as designated (P+4/P(-11)/35P+), a non-piliated variant was isolated at a frequency of 3.86 x 10(-3). C. pilosum was thus alternated between piliated and non-piliated at a fairly high frequency, suggesting that the pili may undergo phase variation. This is the first finding of phase variation of the pili of Gram-positive bacteria.

Corynebacterium↗
PubMed1991

[A prominent retrograde flow in coronary artery in patients with hypertrophic cardiomyopathy].

Pathophysiology and clinical significance of a systolic backward flow in the epicardial coronary artery have not been elucidated. Using a 20 MHz Doppler catheter, we assessed coronary flow velocity waveforms in the left anterior descending coronary artery in 19 patients with hypertrophic cardiomyopathy (HCM) and 11 patients without apparent cardiac abnormalities as control subjects. Systolic flow fraction was smaller in HCM than in controls. Only 4 patients with HCM showed a prominent retrograde flow persisting during almost the entire systole. All the 4 had marked cavity obliteration and two of them had systolic intraventricular pressure gradients of 80 and 110 mmHg respectively. Exercise thallium-201 ECT revealed that myocardial hypoperfusion was more frequent in those 4 patients. Through these observations, it is concluded that a high intramyocardial systolic pressure combined with a relatively low coronary perfusing pressure may result in a large systolic retrograde flow in the left epicardial coronary artery, and that it may be related to myocardial ischemia in patients with HCM.

Adult↗
PubMed1990

An instrument for harvesting the outer table of the skull.

An angled oscillating saw devised for in situ harvesting of the outer table of the skull is presented. With its tip toward the outer table, this saw runs less risk of injuring the inner table and entering the cranial cavity. We have experienced no complication due to the harvesting of the outer table using this instrument.

Bone Transplantation↗
PubMed1990

[A case of pulmonary paraganglioma].

A pulmonary paraganglioma that was discovered incidentally as a solitary coin lesion on abdominal CT was successfully resected. Though this type of paraganglioma is extremely rare, it needs to be differentiated from certain other pulmonary neoplasms.

Aged↗