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Biomedical subjects

Y S Lo

Publications and source records attributed to Y S Lo.

At least 37 records · Page 2Linked to original sources
PubMed1989

Benzo- and pyrido-1,4-oxazepin-5-ones and -thiones: synthesis and structure-activity relationships of a new series of H1 antihistamines.

A series of novel benzo- and pyrido-1,4-oxazepinones and -thiones which represents a new structural class of compounds possessing H1 antihistaminic activity was synthesized, and the SARs were evaluated. The antihistaminic activity was determined by blockade of histamine-induced lethality in guinea pigs. The sedative potential was determined by comparison of the EEG profiles of the compounds with those of known sedating and nonsedating antihistamines. Several of the compounds were shown to possess potent H1 antihistaminic activity and to be free of the cortical slowing with synchronized waves and spindling activity found in the EEG of sedative antihistamines. One compound, 2-[2-(dimethylamino)ethyl]-3,4-dihydro-4-methylpyrido[3,2-f]-1,4- oxazepine-5(2H)-thione (rocastine) is currently undergoing clinical evaluation as a nonsedating H1 antihistamine.

Animals↗
PubMed1988

Long-segment coronary ulcerations in survivors of sudden cardiac death.

Angiographically irregular coronary stenoses usually represent plaque rupture with or without superimposed thrombi. Long-segment coronary stenoses with diffuse irregularities (type IIB morphology) have been shown to be more prevalent than focal irregular lesions (type IIA morphology) in survivors of cardiac arrest without acute myocardial infarction. To further understand the pathogenetic importance of type IIB morphology, the clinical and angiographic characteristics in 59 such patients were analyzed. Type IIB lesions accounted for 63% of all type II lesions. Type IIB patients were older than type IIA patients (p less than 0.05). There was a tendency for type IIB morphology to be associated with more extensive disease than other types of lesion morphology (p less than 0.10). Type IIB morphology probably reflects more advanced atherosclerosis. Platelet microemboli may precipitate spasm and/or acute ischemic ventricular tachyarrhythmias. It is possible that long-segment coronary ulcerations are associated with a higher risk for local coronary thromboembolism, and hence with sudden death, than focal lesions.

Aged↗
PubMed1988

Angiographic coronary morphology in survivors of cardiac arrest.

Autopsy studies in victims of sudden coronary death revealed intramyocardial platelet aggregates with microscopic myonecrosis downstream from ruptured atherosclerotic plaques. Ruptured plaques usually manifest angiographically as irregularly bordered (type II) lesions. To investigate the possible pathogenic role of ruptured plaques in arrhythmic death, we analyzed clinical, angiographic, and electrophysiologic data from 49 survivors of cardiac arrest without acute myocardial infarction. All patients had greater than or equal to 50% stenoses of greater than or equal to one coronary artery; 16 had type II morphology, and 33 did not. Type II morphology was more prevalent in patients without inducible sustained monomorphic ventricular tachycardia (11 of 22 or 50%) than in those with it (five of 27 or 19%), p less than 0.05, and patients without akinetic or dyskinetic segments (eight of 14 or 57%) than in those with them (eight of 34 or 24%), p less than 0.06. Thus type II morphology is more prevalent in patients without a demonstrable anatomic and/or electrophysiologic substrate for reentrant ventricular tachycardia, indirectly implicating ruptured plaques in the pathogenesis of cardiac arrest in this subset of patients.

Aged↗
PubMed1987

Electrophysiologic study in the management of cardiac arrest survivors: a critical review.

This review discusses the value and limitations of EPS in the management of cardiac arrest survivors. Uncertainties associated with EPS include a lack of consensus with respect to stimulation protocol, end points for VT suppression during drug testing, significance of induced polymorphic VT or VF, and timing of EPS after myocardial infarction. Despite methodologic shortcomings in most clinical studies, a useful body of knowledge has emerged. In cardiac arrest survivors, incidence of inducible sustained VT ranged from 35% to 75%. Where induced VT (sustained or nonsustained) was successfully suppressed, recurrent arrhythmic events occurred in 0% to 33% of patients over a 1- to 5-year follow-up period. Failed regimens correlated with a high risk of arrhythmic recurrence. EPS also helps to select patients for the implantable defibrillator or electrocardiac surgery. In conclusion, EPS appears empirically useful in the management of cardiac arrest survivors with coronary artery disease; its value in other disease entities is uncertain.

Atrial Fibrillation↗
PubMed1985

Intravenous versus intracoronary streptokinase in acute myocardial infarction.

Nine studies specifically dealing with the comparison of intravenous streptokinase (IVSK) and intracoronary streptokinase (ICSK) in the treatment of acute myocardial infarction (MI) were analyzed to determine if IVSK is as efficacious as ICSK in achieving thrombolysis. Pooled data from the studies yielded success rates of 73% for IVSK and 72% for ICSK. Considering that the studies which did not perform preintervention angiogram may have overestimated the thrombolytic success rate in IVSK patients, there is a possibility that ICSK may be slightly more effective in achieving acute reperfusion. Bleeding complications were similar, and a systemic lytic state was observed in both treatment groups. No definitive conclusions can be drawn regarding the differences between groups in improvements of left ventricular function and mortality rates. ICSK has the advantage of direct documentation of reperfusion and spares the patient the risk of anticoagulation should the attempt fail. On the other hand, IVSK is cheaper, easier to administer, and can logistically be given earlier (even in the emergency room or ambulance) than ICSK; it is therefore more widely available, and may be the preferred mode of treatment in community hospitals where cardiac catheterization facilities are not readily available, if streptokinase is to be given at all.

Cardiac Output↗
PubMed1984

In vitro biological activities of 6-isosteric penicillins and 7-isosteric cephalosporins.

Antibiotic and penicillinase inhibitor activities of various penicillin and cephalosporin analogs are reported. The compounds include C-6 penicillin and C-7 cephalosporin carbon, oxygen and sulfur analogs obtained by replacing the NH of the amide side chains with CH2, O and S, respectively. In almost all cases, analogs were considerably less active than the standard compounds (benzylpenicillin and cephalothin). However, some of the analogs act as penicillinase inhibitors.

Bacteria↗
PubMedDate not supplied

Postinfarction angina.

In conclusion, the PIA patient is at high risk, with higher early as well as late mortality. The pathophysiology of PIA is complex and may vary from patient to patient. The concepts of ischemia at a distance and ischemia in the infarct zone have led to a better understanding of early PIA. Coronary spasm may play an important role in most PIA patients as in the general population of patients with angina pectoris. Medical therapy is efficacious in many, although it may on rare occasion aggravate myocardial ischemia. Urgent coronary arteriography is generally safe and should be performed as soon as possible for medically refractory PIA. CABG appears to be safe in experienced hands, but its timing must be individualized. The IABP should be reserved for more unstable patients for fear of vascular complications. Randomized controlled trials such as the BARI Trial will further compare PTCA with CABG.

Adrenergic beta-Antagonists↗
PubMedDate not supplied

[Menkes' kinky hair disease: report of one case].

A male infant, 2-month-old, was delivered normally at term. He weighed 3.0 Kg and was stated to be quite well until convulsion was presented at the age of 1 month. The convulsion was complex partial seizure in character. Physical examinations showed body weight 2.7 Kg (less than 3 percentile), body temperature 35.7 degrees C, opisthotonic in posture, staring of eyes and unawareness of the outside environment. His hair appeared sparse, coarse and light yellowish color. Laboratory examinations showed normal hemogram and cerebrospinal fluid data. Low serum copper (10 mg/dl), ceruloplasmin (13.5 mg/dl) and hair copper (9.73 ppm) were found. The EEG revealed paroxysmal sharp waves with phase reverses at right temporal and occipital area. Fundus examination showed bilateral optic atrophy. Microscopic examination of the hair showed pili torti (twisting) of the hair. The baby was persisted in hypothermia, poor activity and poor weight gain. The convulsion was poorly controlled and progressed in opisthotonus. The baby died of unknown cause at 3 months of age.

Brain Diseases, Metabolic↗