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Biomedical subjects

M Hong

Publications and source records attributed to M Hong.

At least 145 records · Page 8Linked to original sources
PubMed1991

Relation between acute ventricular arrhythmias, ventricular late potentials and mortality in acute myocardial infarction.

The relation between ventricular late potentials and the occurrence of acute (in-hospital) and hyperacute (before hospital admission) ventricular tachycardia or fibrillation was studied in 281 consecutive patients with uninterrupted acute myocardial infarction. The prevalence of late potentials was significantly higher in patients with than without ventricular tachycardia/fibrillation (65 vs 22%; p less than 0.01). These relations persisted among patients with left bundle branch block, although a different definition was used for identifying late potentials in these patients. Multivariate analysis showed that presence of late potentials and peak creatine kinase enzyme level were the only 2 independent variables associated with early ventricular tachycardia/fibrillation. Total in-hospital mortality, as well as in-hospital cardiac mortality, was significantly higher among patients with than without acute ventricular tachycardia/fibrillation. However, at 1 year, mortality rates did not differ between the 2 groups. The following conclusions were drawn from this study: (1) Late potentials are closely related to ventricular tachycardia/fibrillation in hyperacute and acute phases of infarction. (2) Presence of left bundle branch block does not mitigate against the finding of late potentials in these patients. (3) Early ventricular tachycardia/fibrillation in acute infarction is related to large infarctions and to a high in-hospital mortality rate.

Aged↗
PubMed1991

The effects of streptozotocin induced diabetes mellitus and fish oil compound on gene expression of atrial natriuretic peptide in rat.

1. Adult male Wistar rats were injected with streptozotocin (STZ: 55 mg/kg) for inducing diabetes. Then blood and atria for RNA extraction were withdrawn from rats treated 3 and 11 weeks previously with STZ respectively. Atrial total RNA were extracted with cold phenol method. The ANP mRNA contents were determined using Dot blot hybridization technique with alpha-32-P-labelled r-prepro ANP cDNA probe. 2. Plasma glucose was increased and plasma immunoreactive insulin was lowered in rats at 3 and 11 weeks after injection of STZ. ANP gene expression in diabetic rats was depressed. ANP mRNA contents in rats treated 3 and 11 weeks with STZ were 86.4% and 31.7% of that of control rats. 3. Three weeks after treatment of STZ, the rats were gastrically perfused with FOC (Fish Oil Compound) (0.355 ml/kg) once a day successively until 11 weeks. This treatment induces lower blood pressure in rats. ANP gene expression in FOC group was apparently recovered which had been decreased because of the effect of diabetes mellitus.

Animals↗
PubMed1991

[Effects of aging and ginsenoside on atrial natriuretic peptide gene expression].

We investigated the levels of atrial natriuretic peptide (r-ANP) gene expression in the atria of rats aged 2-3 months and 14-18 months. In the meantime, we studied the effects of ginsenosides on r-ANP gene expression by determining the content of ANP messenger ribonucleic acid (r-ANP-mRNA). Male and female rats were abdominally injected aqueous solution of ginsenoside (prepared from ginseng stems and leaves (G-SL) and ginseng roots (G-R) 50 mg/kg body weight, once a day, for 7 days. Atrial total RNA was extracted by cold phenol method. The specificity and relative contents of r-ANP-mRNA were determined by using Northern blot and Dot blot hybridization respectively with alpha-32P-labeled r-ANP-cDNA probe. The results showed that the r-ANF-mRNA levels in male and female rats at the age of 14-18 months were about 15% and 60% of those in male and female rats at the age of 2-3 months. G-SL and G-R increased r-ANP-mRNA contents in male rats at the age of 14-18 months by 1 fold and 1.7 folds respectively; whereas they decreased r-ANP-mRNA contents in male rats at the age of 2-3 months. No apparent effects of ginsenosides on ANP gene expression was observed in female rats. These results showed that ANP gene expression is more declined in elder rats and ginseng has certain effects in the aspect of heart endocrine to combat decrepitude.

Aging↗
PubMed1991

[Effect of adrenal cortical hormones on the expression of atrial natriuretic peptide (ANP) gene in vivo].

Experiments were conducted in intact and adrenalectomized female Wistar rats given dexamethasone, deoxycorticosterone or both, and atria total RNA was extracted with cold phenol method and hybridized to rat ANP-cDNA probe labeled with alpha-32P. The ANP gene transcripts in intact rats receiving dexamethasone and in adrenalectomized rats receiving dexamethasone and deoxycorticosterone increased by 2-fold, while there were no significant changes in the other groups. The results suggest that glucocorticoids enhance ANP gene expression, an effect relying on the presence of mineralocorticoids which given alone does not give rise to ANP gene expression enhancement.

Animals↗
PubMed1991

[Extra-articular rearrangement of temporomandibular joint internal derangement and associated neuromuscular disorders].

This report introduces a new method for treatment of TMJ internal derangements and associated neuromuscular disorders. This operation consists of two main surgical procedures: (1) To detach the muscular attachments of masseter, temporal, and internal pterygoid muscle from the mandible and to detach the external pterygoid muscle from the external pterygoic plate for eliminating the neuromuscular disorders. (2) To reposition the condylar head from the glenoid fossa after making a vertical osteotomy on the posterior portion of the ramus for eliminating the internal derangements of the joint. Therefore, the causes of considerable embarrassment of TMJDS could be eliminated and the iatrogenic trauma to the joint could be avoided. Since 1987-1990, 15 cases have been successfully performed.

Adolescent↗
PubMed1990

The effects of salt-loading and dehydration on atrial natriuretic peptide (ANP) gene expression.

1. Effects of sodium loading and dehydration on ANP gene expression were investigated in rats. 2. ANP-mRNA was determined using Northern blot and dot blot hybridization technique with alpha-32P-labeled r-preproANP-cDNA probe. Salt loading increased the ANP-mRNA content in atria. Correlation with ANP-mRNA content and the plasma sodium concentration was established. 3. Deprivation of water for 2 and 4 days increased ANP-mRNA 2.1- and 1.6-fold, respectively. 4. These results demonstrated that water-salt balance affects the ANP-gene expression.

Animals↗
PubMed1990

Reexamination of dopamine as the prolactin-release inhibiting factor (PIF): supplementary agent may be required for dopamine to function as the physiological PIF.

A large number of studies have been performed concerning dopamine's inhibitory effect on prolactin release, but many of these studies have examined the effect of dopamine dissolved in a solution containing ascorbic acid. Ascorbic acid, routinely used to protect dopamine from oxidation, alone does not stimulate or inhibit prolactin release, but it can potentiate the inhibitory effect of dopamine in a static monolayer culture system by approximately 100 times. We have closely examined the inhibitory effect of dopamine on prolactin release in the absence of ascorbic acid using a perifusion system. Male rat adenohypophyses were dispersed with trypsin and cultured in a Petri dish to form cell clusters. Inhibition of prolactin release by dopamine (1 mumol/L) in the absence of ascorbic acid was sustained for only 63 min during the 2-h perifusion period. Following a 2-h period of incubation of dopamine in the same experimental solution, the dopamine concentration was reduced from 1 to 0.18 mumol/L, yet this "2-h-old dopamine" was still effective in inhibiting prolactin release (approximately 30 min). This result suggests that the lactotrophs may be desensitized by chronic exposure to a high concentration of dopamine in the absence of ascorbic acid. In contrast, when a low concentration of dopamine (3 nmol/L) containing ascorbic acid (0.1 mmol/L) was perifused, inhibition of prolactin release was sustained for the entire 2-h perifusion period. Although there may be a large number of explanations for dopamine's transient inhibitory effect on prolactin release, the present results suggest that dopamine may require supplementary agent(s) to effectively inhibit prolactin release and thus function as the prolactin release inhibitory factor (PIF).(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1990

[TMJ reconstruction of the intracapsular condylar vertical fracture].

According to literature, it is difficult to make an early correct diagnosis and treatment of the intracapsular condylar vertical fracture. The author recently suggested a new method to diagnose and treat this kind of fracture with an optimal result. The diagnostic and treatment procedures are: 1. To take a condylo-pterygo-maxillo-oblique tomography which can clearly demonstrate the position of the bone fragment. 2. To remove the bone fragment by submandibular incision with an oblique osteotomy of the posterior part of the ramus. Therefore the secondary injury to the disk and the superior cavity could be avoided that is essential for TMJ reconstruction. 3. To reconstruct the TMJ after condyloplasty under the centric relation. Eight cases were successfully treated by this method. In this paper the details of the operation are described and discussed.

Adult↗
PubMed1990

Actions of beta-endorphin and related peptide fragments on a pressor response induced by cholinergic stimulation.

The present study examined the antagonist potential of shorter beta-EP1-31 related peptide fragments in an opioid-sensitive model of blood pressure. In urethane-anesthetized rats, pretreated with methyl atropine, physostigmine (25-200 micrograms/kg i.v.) produced a pressor response that was stereoselectively depressed by i.c.v. levorphanol, an action reversed by naloxone. beta-EP1-31 and beta-EP1-27(H) (5-20 micrograms i.c.v.) also depressed the physostigmine-induced pressor response in a naloxone-reversible manner. However, injections of beta-EP1-27(O) or beta-EP1-26(H) failed to influence this response or to reverse the depressor action of levorphanol. These findings show that shorter fragments of beta-EP1-31 do not mimic the action of naloxone in an opioid-sensitive model of blood pressure.

Animals↗
PubMed1990

Observations on the treatment of coronary heart disease by kuo guan qu yu ling.

Based on the therory of promoting flow of qi and dispersing blood stasis, the KUO GUAN QU YU LING coronary--dilating and stagnation--dispersing) powder in capsules were prepared for the treatment of 60 cases of coronary heart disease. After a 30 day course of treatment, cardiac ischemia was improved in 64.7% and the symptom of angina pectoris was relieved in 61.7% of the patients. This drug also acted to reduce blood lipids and to improve left cardiac function. Pharmacological study indicated that this preparation improved the tolerance of cardiac muscle against anoxia and prevented ventricular fibrillation and cardiac damage from ischemia.

Adult↗
PubMed1989

Decreased incidence of ventricular late potentials after successful thrombolytic therapy for acute myocardial infarction.

In some patients with acute myocardial infarction, low-amplitude potentials that prolong the QRS complex, termed "late potentials," can be recorded on a signal-averaged electrocardiogram. The presence of these late potentials is known to be associated with an increase in the risk of ventricular tachycardia and sudden death. Because patients with acute myocardial infarction who receive thrombolytic therapy have a reduced incidence of ventricular tachyarrhythmia and sudden death, we sought to determine whether such patients also have a decreased incidence of late potentials. We studied 106 patients less than 75 years of age who were admitted with a first myocardial infarction and in whom a signal-averaged electrocardiogram was recorded within 48 hours of admission. Within four hours of the onset of chest pain, tissue plasminogen activator (t-PA) was given to 44 patients, and 62 were treated conventionally. In the t-PA group, late potentials were recorded in 2 of 44 patients (5 percent), as compared with 14 of 62 (23 percent) in the conventionally treated group (P = 0.01). Furthermore, among the patients treated with t-PA, continued occlusion of the infarct-related artery was related to the presence of late potentials. In the t-PA group, late potentials were recorded within 24 hours of angiography in 2 of the 6 patients with an occluded infarct-related artery, as compared with none of the 38 patients with a patient infarct-related artery. Our data suggest that successful thrombolytic therapy is associated with a marked reduction in the incidence of late potentials on the signal-averaged electrocardiogram. Long-term follow-up will be required to determine whether this finding predicts a reduced incidence of subsequent ventricular tachyarrhythmia and sudden death.

Cardiac Pacing, Artificial↗
PubMed1989

[Excision of condylar osteochondroma by vertical ramisection with immediate TMJ reconstruction].

In literature, excision of condylar osteochondroma is usually performed by preauricular incision. In Oct 1984 according to the experience of "Z" form osteotomy and bone graft to reconstruct the TMJ, a new method for excision of condylar osteochondroma was used by the first author, i.e. (1) making a vertical ramisection by subauricular incision; (2) excising the condylar osteochondroma with the posterior part of the ramus; (3) excising the condyle with osteochondroma on the surgical table, and (4) immediately reconstructing the TMJ with the surplus bone fragment at the same operation. Since 1984-1987, 7 cases have been performed by this method with excellent results. The details of the operation were described and discussed.

Adult↗