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Biomedical subjects

J Kubota

Publications and source records attributed to J Kubota.

At least 55 records · Page 3Linked to original sources

Effects of N-terminal peptide of salmon proopiocortin on interrenal function of the rainbow trout.

Effects of N-terminal peptide of salmon proopiocortin (salmon NPP-I) on cortisol secretion was examined in vitro using diced interrenal tissue from the rainbow trout, Salmo gairdneri. ACTH(1-24) at concentrations of 1 to 50 nM stimulated cortisol secretion in dose-dependent manner, whereas salmon NPP-I had no effect over a range of 50 pM to 500 nM. Cortisol secretion in response to various doses of ACTH(1-24) was modified slightly when 1 to 100 nM of salmon NPP-I was added to the incubation medium together with ACTH. An augmentation of in vitro secretion of cortisol in response to ACTH(1-24) was observed when the interrenal was removed from the trout pretreated with one IU of porcine ACTH but not with 10 micrograms of salmon NPP-I. A slight but significant potentiating effect of salmon NPP-I (10 or 100 nM) on the ACTH-induced cortisol secretion was observed when the trout was sensitized to ACTH by porcine ACTH pretreatment. Furthermore, six daily injections of salmon NPP-I into the trout induced hyperplasia of interrenal tissue. These findings suggest that NPP-I, together with ACTH, may be involved in controlling interrenal function in the trout. Such activities could be due to conservative region in the N-terminal portion of NPP.

Adrenal Glands↗

Development and validation of a salmon prolactin radioimmunoassay.

A highly specific radioimmunoassay (RIA) for the measurement of prolactin (PRL) in the plasma and pituitary of salmonid fishes was developed using a rabbit antiserum to chinook salmon (Oncorhynchus tschawytscha) PRL. The PRLs purified from chinook salmon and chum salmon (O. keta) pituitaries showed exactly the same competitive inhibition curves in the RIA, regardless of iodination of either hormone. The displacement curves for pituitary extracts and plasma from several salmonids, including chum, coho, and amago salmon, rainbow trout, and Japanese charr, were parallel to the salmon PRL standard, whereas those from the eel, goldfish, carp, and tilapia showed negligible cross-reactivity. Negligible cross-reactivity was also seen with plasma from hypophysectomized rainbow trout or coho salmon. None of the mammalian PRL or growth hormone (GH) preparations, bullfrog PRL, or presumptive chum salmon "gonadotropin" and eel "PRL" cross-reacted in the PRL RIA. Presumptive chum salmon GH showed less than 0.05% cross-reactivity. The RIA sensitivity was less than 0.1 ng of the salmon PRL standard per milliliter. The immunoreactive plasma PRL levels in mature chum salmon were below 1 ng/ml in seawater. The plasma PRL in females increased to about 8 ng/ml 1 day after transfer to fresh water, and high levels (2-4 ng/ml) were maintained during 3-7 days after the transfer. In contrast, when males were transferred to fresh water, an increase in plasma PRL was seen only 1 day after the transfer. A significant decrease in plasma osmolality was observed in both males and females after transfer to fresh water. No change was observed either in plasma PRL or osmolality, when fish were transferred from seawater to seawater.

Animals↗

REM sleep deprivation effect on apomorphine-induced gnawing is reversed by dexamethasone.

Glucocorticoid feedback was manipulated in rats deprived of REM for six days or left undisturbed in their home cages. One half of each group received concurrent dexamethasone (400 micrograms/kg), while the other half received corn oil. On test day, rats were observed for 5 min, injected with apomorphine (0.8 mg/kg, i.p.), and again observed. Dexamethasone revealed REM-deprivation-enhanced stereotypical gnawing, but had no effect on REM-deprivation-reduced rearing, suggesting the involvement of catecholamine depletion by non-specific stress-related factors in the former REM deprivation effect.

Animals↗

Role of coronary spasm in different anginal syndromes.

Angina pectoris is a clinical syndrome caused by transient myocardial ischaemia due to an imbalance between myocardial oxygen demand and supply. It is now evident that coronary artery spasm plays an important role in the pathogenesis of various forms of angina pectoris. Angina pectoris that is mainly caused by coronary artery spasm (coronary spastic angina) has one or more of the following characteristics: 1) the attack occurs at rest, 2) the attack is associated with ST-segment elevation in the ECG, 3) the attack has a variable exercise threshold, and 4) the attack is suppressed by Ca-antagonists but not by beta-adrenergic blocking agents. On the other hand, angina pectoris that is caused by increased myocardial oxygen demand in the presence of severe and extensive organic stenosis (organic angina) has the following characteristics: 1) the attack is induced by constant amount of exertion irrespective of hour and day and is relieved by rest, 2) the attack is associated with ST-segment depression in the ECG, and 3) the attack is suppressed by beta-adrenergic blocking agents, which decrease myocardial oxygen demand.

Angina Pectoris↗

The effects of reperfusion of infarct-related coronary artery on serum creatine phosphokinase and left ventricular function.

In 31 patients with transmural myocardial infarction in whom coronary arteriography was performed within 8 hours after the onset of symptoms, we examined (1) the effect of restoration of coronary blood flow on serum CPK time-activity curve and (2) the relationship between cumulative CPKr and the left ventricular function in the chronic phase. We divided 31 patients into 2 groups: Group A consists of 19 patients in whom coronary reperfusion was established. Group B consists of 12 patients whose coronary artery remained occluded. In group A, the time required to reach peak serum CPK activity was significantly shorter than in group B. When comparing CPKr with percent abnormally contracting segment (%ACS) in 2 groups, correlation between CPKr and %ACS was not good, but it revealed linear relation in both group A and B. CPKr divided by %ACS (CPKr/%ACS) was significantly higher in group A than in group B. We conclude that reperfusion of infarct-related coronary artery changes serum CPK time-activity curve resulting in earlier appearance of peak serum CPK and that infarct size cannot be estimated by serum CPK level alone.

Adult↗

[Reconstruction of the large scalp defect by free flap transplantation].

The reconstruction of a large scalp defect is extremely difficult on many occasions and repeated operations or a long-term hospitalization is often required. In addition, unsatisfactory results are not unusual. However, it is now possible to perform reconstruction by a one-stage operation of free tissue transplantation (free flap) using microsurgical vascular anastomosis which has rapidly developed in the past ten years. We performed reconstructions applying latissimus dorsi musculocutaneous, greater omentum, groin and scapular flaps. The advantages with the free flap are: (1) one-stage reconstruction is possible; (2) no restrictions on the postoperative position, (3) the flap, which is independent of the blood supply from the recipient, well survives on the recipient with an insufficient blood supply and (4) the damage at the donor site can be minimized. On the other hand, its disadvantages are as follows: (1) the operation requires microsurgical vascular anastomoses; and (2) recipient vessels should be normal. The above report was based on favorable results we obtained in 6 cases of reconstruction with free flap applying microvascular techniques.

Aged↗