Transient absorption due to the self-trapped exciton localized at an iodine dimer in KCl:I.
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Journal Article↗
Biomedical subjects
M Hirai
Publications and source records attributed to M Hirai.
Usefulness of QRST time-integral values of 12-lead electrocardiograms in diagnosing healed myocardial infarction complicated by left bundle branch block.
The usefulness of QRST time-integral (IQRST) values of 12-lead electrocardiograms for diagnosing a prior myocardial infarction complicated by left bundle branch block (LBBB) was determined. The study consisted of 25 patients with LBBB (11 with and 14 without myocardial infarction). The IQRST values in each lead point of 12-lead electrocardiograms were calculated. Data from 607 normal subjects were used as controls and mean +/- 2 standard deviations was regarded as the normal range. The following parameters were derived: number of leads less than the normal range of IQRST values (nQRST) and sum of the differences between the normal mean IQRST value and IQRST value of a given patient in leads where this value was less than the normal range (sigma QRST). The criteria of nQRST (12-lead) greater than or equal to 5 and sigma QRST (12-lead) greater than or equal to 500 microV in 12-lead electrocardiograms were selected on a relative cumulative frequency distribution and demonstrated the presence of a myocardial infarction in LBBB with a sensitivity of 82% and a specificity of 100% for each. With regard to the localization of the myocardial infarction, the criterion of sigma QRST (V1-6) greater than or equal to 300 microV in leads V1-6 of 12-lead electrocardiograms demonstrated the presence of an anterior myocardial infarction in the LBBB with a sensitivity of 88% and a specificity of 77%. It was difficult to localize an inferior myocardial infarction in patients with LBBB by using IQRST values of inferior leads.(ABSTRACT TRUNCATED AT 250 WORDS)
Adult↗
Protein kinase C activity and protein phosphorylation in mouse eggs.
The treatment of mouse eggs with phorbol esters and diacylglycerol inhibits sperm penetration and results in biochemical modification of the zona pellucida. In this report, we have demonstrated the presence of protein kinase C (PKC) activity in mouse eggs as determined by 12-O-tetradecanoyl phorbol-13-acetate (TPA) dependent in vivo and in vitro protein phosphorylation in mouse eggs. When mouse eggs were radiolabeled with [32P]phosphate and treated with TPA, two specific proteins, 70 and 20 kDa, were phosphorylated. The 70-kDa protein was also phosphorylated in vitro by endogenous PKC. In addition, we have shown that exogenous PKC induced the in vitro phosphorylation of 70-, 55-, and 20-kDa proteins in egg extract. The 70-kDa protein was also phosphorylated in vitro after treatment of the cytosol fraction of mouse eggs with TPA, suggesting that this protein might be a specific substrate for PKC and that it is located in the cytosol. These results demonstrate that mouse eggs contain PKC activity and suggest that PKC-catalyzed protein phosphorylation of specific proteins might be involved in the regulation of egg-induced modification of the zona pellucida.
Animals↗
Hemodynamic assessment of chronic venous insufficiency.
To study the pathogenesis of chronic venous insufficiency (CVI), photoplethysmography and strain-gauge plethysmography were simultaneously performed in 84 patients. Of the 128 limbs studied, 24 were normal, 64 had primary varicose veins and 40 had post-thrombotic syndrome. Venography was also performed in all patients. The results of this study indicate that reflux in the superficial veins is the main pathophysiology involved in the development of CVI, though incompetence of the perforators and deep veins plays some role. In post-thrombotic syndrome, however, CVI is mainly a sequel of deep venous incompetence, the condition being complicated by incompetent perforators and superficial venous reflux.
Chronic Disease↗
Toxic effects of ingested lead shots in domestic fowls.
Lead poisoning from ingested shots is thought to be a major cause of high mortality in waterfowls throughout the world, and some millions of fowls die each year. However, there have been no other Japanese studies regarding lead toxicity in birds from ingested lead shots. We used domestic fowls instead of waterfowls as the experimental birds, in order to make clear the distribution and the toxic effects of lead shot in the birds. In a 1-wk follow-up study, two, four, and eight #4 lead shots were administered orally. A dose-dependent increase of the lead concentrations in blood, brain, liver, kidney, lung, spleen, bone, and epidermis of the gizzard was observed. In the 12-wk follow-up study, twenty domestic fowls were used and eight #4 lead shots were administered to the experimental birds. Lead concentrations in brain, liver, kidney, bone, ovary, fat tissue, and breast muscle increased more than in the 1-wk follow-up study. The observed lead concentrations of organs in the domestic fowls were lower than those of the other species used in past studies. The blood lead concentrations increased up to the third week and a remarkable suppression of delta-aminolevulinic acid dehydratase activity in red blood cells and elevation of free erythropoietic protoporphyrin were observed in the exposed group. Body weight loss, loss of hair, and neurological symptoms were also observed. However, there were no mortalities during the 1- and 12-wk studies.
Administration, Oral↗
Detection of myocardial infarction in the presence of Wolff-Parkinson-White syndrome by QRST isoarea map in dogs.
The possibility of detecting myocardial infarction (MI) in the presence of Wolff-Parkinson-White (WPW) syndrome by means of body surface QRST isoarea maps was studied in eight dogs. Eighty-seven body surface ECGs were recorded simultaneously. Recordings were taken during right atrial (RA) and right atrial and right ventricular (RA + RV) sequential pacing, which simulated WPW syndrome, during control periods and at 1-hour intervals for up to 5 hours after occlusion of the left anterior descending coronary artery. In ECGs during the RA drive, diagnostic findings of MI such as abnormal Q waves were observed but became obscure during the RA + RV drive. On the contrary, the QRST values over the anterior chest during both drives were positive soon after coronary occlusion, decreased gradually as time passed, and became abnormally negative after 5 hours. The QRST isoarea maps during RA and RA + RV pacing showed quite similar patterns and were highly correlated with each other throughout this study (r greater than 0.95). These findings demonstrate that localized abnormalities resulting from MI are evident in QRST isoarea maps even in the presence of preexcitation and fusion.
Animals↗
Percutaneous transaortic closure of postinfarctional ventricular septal rupture.
We report a case of successful closure of a postinfarctional ventricular septal defect by means of the transaortic approach with a balloon catheter. This method brought about substantial improvement in cardiopulmonary function before an elective operation and made it possible to successfully perform the operation on the patient, an 81-year-old woman, on the 22nd day of admission.
Aged↗
Ritodrine-induced agranulocytosis.
This is the first reported case of development of agranulocytosis induced by continuous intravenous infusion of a large quantity of ritodrine hydrochloride for tocolysis. It is suspected that the pathophysiological mechanism is a dose-related toxic reaction and a cell loss maturation process of myelocytes.
Adult↗
Effects of sudden changes in cycle length and pacing site on canine cardiac surface QRST isoarea maps.
The effects of changes in paced cycle length alone and changes in both paced cycle length and site of pacing on canine cardiac surface QRST isoarea maps were studied. The correlations between QRST isoarea maps acquired during right ventricular pacing at 900 ms and 700 ms averaged 0.97. The correlations between maps acquired during RV pacing at 900 ms and 500 ms averaged 0.94. The root mean square value of QRST areas progressively decreased as cycle length was decreased from 900 ms to 700 ms and then to 500 ms. This suggests that the pattern of distribution of repolarization properties remained the same and the magnitude of difference in repolarization properties decreased as cycle length was decreased. The correlation coefficients of QRST isoarea maps acquired during RV pacing at 900 ms and those acquired during left ventricular pacing at 700 ms and 500 ms averaged 0.74 +/- 0.01 and 0.68 +/- 0.03, respectively. These correlations were lower than those associated with a change in pacing cycle length alone. Root mean square differences in QRST areas recorded during changes in both pacing site and pacing cycle length were greater than the differences associated with change in cycle length alone. This suggests that changes in activation sequence altered repolarization properties more than they were altered by changes in cycle length alone. QRST isoarea maps have been proposed for assessing arrhythmia vulnerability. The results of this study provide a framework for interpreting QRST isoarea maps acquired during supraventricular tachycardias, premature ventricular complexes, and sustained ventricular tachycardias.
Animals↗
Modulation of collision-induced changes in canine heart repolarization by cycle length.
The possibility that cycle length modulates the electronic effect of activation sequence on repolarization was investigated in experiments using isolated canine cardiac Purkinje strands, in situ canine ventricular myocardium, and computer simulations. Action potential durations and refractory periods during one-way propagation were compared to those obtained during action potential collision. In both the computer simulations and the Purkinje strand experiments, collision decreased action potential duration more at long cycle lengths than at short cycle lengths. Comparably, collision of activation fronts in ventricular myocardium was associated with greater reductions in refractory period during pacing at long cycle lengths than at short cycle lengths. Theoretic considerations indicate that the magnitude of electrotonic effects of activation sequence on repolarization are directly related to action potential height and the square root of membrane resistance during repolarization and are inversely related to conduction velocity. In computer simulations and Purkinje strand experiments, changes in conduction velocity and action potential height elicited by decreasing cycle length could not fully account for the cycle length dependence of collision-induced changes in repolarization. Time-varying membrane resistance of a single cell was calculated in the simulations by briefly hyperpolarizing the membrane and determining the change in total ionic current. Membrane resistance during repolarization was less at short cycle lengths than at long cycle lengths. The results suggest the cycle length dependence of collision-induced changes in repolarization results largely from the effect of cycle length on membrane resistance during action potential repolarization, with changes in action potential height and conduction velocity playing a lesser role.
Action Potentials↗
Endothelin-3 stimulates the hypothalamic-pituitary-adrenal axis.
Endothelin-3 (ET-3) is a member of the novel vasoconstrictive peptide family, identified in porcine central nervous system. Intravenous bolus injection of 1000 pmol/kg of ET-3 in freely moving rats caused significant increases in plasma ACTH and corticosterone levels, almost equivalent to those of 100 pmol/kg of rat corticotropin-releasing hormone (rCRH). The action of ET-3 was virtually abolished by pretreatment of CRH-antagonist, alpha-helical CRH. When ET-3 was added to cultured anterior pituitary cells, neither direct stimulation of ACTH release nor potentiation of rCRH action was noted. The results indicate that ET-3 may function as a neuropeptide and stimulation of the CRH-neurons, direct or inderect, is mainly responsible for activation of ACTH and corticosterone release.
Adrenal Glands↗
Changes in serum glucocorticoid levels and thymic atrophy induced by phenytoin administration in mice.
The weights of spleen and thymus were recorded and serum glucocorticoid (GC) levels examined in mice injected intraperitoneally with 60 mg phenytoin (PHT) kg body wt. for 3, 8, and 30 days. In mice injected with PHT, the serum GCs were elevated about 4- to 5-fold in 3 days; the higher levels were maintained and accompanied thymic atrophy throughout the experiment. Moreover, dose-dependent changes in serum GC levels and thymus weight were also observed at 3 days. These results indicate that GCs may play an important role in thymic atrophy induced by PHT.
Animals↗
Chromosomal localization of the major histocompatibility complex (MHC) in the rhesus monkey and chimpanzee by fluorescence in situ hybridization.
Genes for the major histocompatibility complex (MHC) were localized by fluorescence in situ hybridization to the long arm of rhesus monkey chromosome 5. This localization contradicts previous reports, based on genetic investigation of somatic cell hybrids, that placed the MHC on chromosome 2 of this species. In the chimpanzee, the MHC loci were localized to 5p21.3, corresponding precisely to their location on human chromosome 6p21.3.
Animals↗
Body surface distribution of abnormally low QRST areas in patients with left ventricular hypertrophy. An index of repolarization abnormalities.
BACKGROUND: QRST isointegral maps (I-maps) have been useful in detecting repolarization abnormalities. We investigated the body surface distribution of abnormally low QRST areas in patients with left ventricular hypertrophy (LVH) and the relation of the abnormalities in I-map to the severity of LVH as assessed by echocardiography. METHODS AND RESULTS: QRST area departure maps were constructed from electrocardiographic (ECG) data recorded in patients with LVH and precordial negative T waves resulting from aortic stenosis (AS) (10 patients), aortic regurgitation (AR) (12 patients), or hypertrophic cardiomyopathy (HCM) with asymmetric septal hypertrophy (22 patients). Fifty normal subjects served as controls. The I-map was constructed from 87 body surface electrocardiograms recorded simultaneously at a sampling interval of 1 msec. The area where the QRST area was smaller than normal limits (mean -2 SD) was designated the "-2 SD area." The echocardiographic left ventricular (LV) mass was calculated by Devereux's method. Patients with large LV masses due to AS or AR had 2 SD areas located over the left anterior chest or the midanterior chest, respectively. The 2 SD area was located over the left shoulder and left anterior chest and had a lingual shape in patients with HCM. The sum of QRST area values less than the normal range (sigma QRST) was significantly correlated with LV mass in patients with AS or AR (r = 0.83 and r = 0.69, p less than 0.01 and p less than 0.05). However, there was no significant correlation between sigma QRST and the severity of LVH in patients with HCM. sigma QRST divided by the number of electrodes in the 2 SD area was significantly greater in patients with HCM than in those with AS or AR. CONCLUSIONS: These findings suggest that abnormalities in patients with HCM are manifest even in mild LVH and that there is a greater disparity of repolarization in hypertrophied left ventricles due to HCM than in LVH due to aortic valve disease. QRST isointegral departure maps may provide ECG evidence of LV mass of patients with AS or AR and of susceptibility to malignant arrhythmias in patients with HCM.
Aortic Valve Insufficiency↗
Chronic venous insufficiency in primary varicose veins evaluated by plethysmographic technique.
Venous hemodynamics were evaluated by plethysmography in normal subjects and patients with venous disorders of the lower extremity, to clarify the pathophysiology of chronic venous insufficiency (CVI) due to primary varicose veins. Expelled volume during five active dorsiflexions of the feet and venous recovery time were calculated to evaluate muscle pump efficiency and valvular competence. Limbs with CVI due to primary varicose veins showed a higher expelled volume and a more shortened refilling time than limbs with simple varicosities. With application of tourniquets, the refilling time normalized in limbs with CVI, as well as in limbs with simple varicosities. These results indicate that a high degree of venous congestion in the distal part of the calf and valvular incompetence of the superficial vein system might cause CVI due to primary varicose veins.
Humans↗
Improvement in wound healing by epidermal growth factor (EGF) ointment. II. Effect of protease inhibitor, nafamostat, on stabilization and efficacy of EGF in burn.
The healing effect of human epidermal growth factor (hEGF) on second degree burn was studied in rats. No improvement in wound healing was found on topical application of EGF alone to burn sites, but an ointment containing EGF and nafamostat mesilate (NM), a protease inhibitor, accelerated the healing rate of burns. The dry weight of the granulation tissue on the wound site in the group treated with EGF plus NM ointment did not change, although that in other groups decreased. After treatment with EGF ointment containing NM, the content of uronic acid, as an index of acid mucopolysaccharide, at 3 d after burn rapidly increased and had recovered to nearly normal levels at 7 d after burn. However, the uronic acid content in the other groups (control, EGF alone, and NM alone) showed a higher value at 7 d than at 3 d. When compared with the control values significant increases in hydroxyproline, as an index of collagen, in the wound site were observed at 7 d after treatment with EGF ointment containing NM. The degradation of [125I]EGF in burned tissue homogenate decreased significantly in a concentration-dependent manner in the presence of NM. Body weights did not change after treatment with EGF plus NM ointment, although the body weights of other treatment groups decreased after burn, suggesting that EGF ointment containing the protease inhibitor, NM, alleviated the effects of burn shock. These findings indicate that the stabilization of EGF at the wound site is an important factor for the expression of its healing effects.
Animals↗
[Effects of ovariectomy on naloxone-modulated hypertension in spontaneously hypertensive rats (SHR)].
Ovariectomy was performed at 4 weeks of age (W), and the rats were used when they were 33 and 75 W old. Systolic blood pressure (BP) was measured by the tail-cuff method. Naloxone (10 mg/kg) was given i.p. Catecholamines (CA) were determined with HPLC. Norepinephrine (NE) was not significantly altered in intact rats by naloxone; however, a significant increase in NE appeared in the plasma, hippocampus, thalamus plus mid-brain and hypothalamus in castrated rats following naloxone. With naloxone treatment, dopamine (DA) was significantly increased in the plasma and hypothalamus, but decreased in the cerebral cortex in intact rats; and with castrated rats, there was a tendency to see an increase in plasma DA and significantly increased levels of DA in the thalamus plus mid-brain and hypothalamus. This suggests that in female brain, lack of estrogen in the castrated rats leads to an increase in intrinsic opiate, and this in turn inhibits CA release. On the other hand, when naloxone was administered to castrated rats, intrinsic opiate was blocked, and, consequently, inhibition of CA release was lost and induction of CA release was enhanced.
Animals↗
[Ketoconazole inhibits the growth of prostatic squamous carcinoma, at which time testicular androgen enhanced in tumor bearing rat].
Donruy male rats were implanted with the tumor in the ventral prostate at 40 days of age; and 9 days later, they were concurrently orchiectomized and started on ketoconazole (Keto) injection (5 or 10 mg/rat/day, s.c.). Twenty days later, the rats were decapitated. The rats were divided into the following treatment groups: 1. Intact, 2. Intact + Keto-10 (10 mg), 3. Implanted (Imp), 4. Imp + Keto-5 (5 mg), 5. Imp + Keto-10, 6. Imp + castrated (Cast), 7. Imp + Cast + Keto-5 and 8. Imp + Cast + Keto-10. Keto induced slight inhibition of tumor growth but coincident castration led to a significant decrease of tumor development. Keto or castration increased adrenal weight. Keto could not alter plasma androgen in intact rats, but enhanced it significantly in low androgen situations as in groups 3 and 6. Keto significantly lowered plasma corticosterone and acted to decrease testicular androgen in group 1 (Intact); and in contrast, Keto acted to increase significantly testicular androgen in group 3 (Imp). These results suggest that: (1) Keto has a direct action to decrease the tumor weight and enhanced androgen in implantation and (2) Keto acts to decrease adrenal steroidogenesis.
Adrenal Glands↗