Biomedical subjects

W L Lee

Publications and source records attributed to W L Lee.

At least 91 records · Page 5Linked to original sources

PubMed1998

Dopamine and dobutamine have different effects on heart rate variability in patients with congestive heart failure.

BACKGROUND: Autonomic dysfunction plays an important role in the pathogenesis, treatment and prognosis of congestive heart failure (CHF). Sympathomimetic amines have been widely used in the treatment of CHF, but reports on their autonomic effects in CHF are rare. This study was designed to evaluate the effects of dopamine and dobutamine on cardiac autonomic function as assessed by heart rate variability (HRV). METHODS: Twenty patients with symptomatic CHF (systolic dysfunction) were enrolled. After recording one-hour baseline electrocardiographs (ECGs), patients were randomly selected for either dopamine (4 micrograms/kg/minute, Group A) or dobutamine (4 micrograms/kg/minute, Group B) treatment for three days. On the third day, a 24-hour ambulatory ECG was recorded and a tilt-table test was performed. Only furosemide and nitrates were allowed for adjunctive therapy. HRV was measured before and after treatment in both time and frequency domains. Frequency-domain HRV was also measured during head-up tilt. RESULTS: After treatment, all patients improved [New York Heart Association fraction (NYHA Fc) 3.7 to 2.0]. Group A patients had higher post-treatment 24-hour HRV than those in Group B. SDNN (standard deviation of the average normal RR intervals in the entire ECG recording), SDANN (standard deviation of the average normal RR intervals for all five minute segments of an entire ECG recording) and SDNN indices in Group A were significantly higher than in Group B (90 +/- 33 ms vs 41 +/- 12 ms, 78 +/- 32 ms vs 36 +/- 11 ms, and 37 +/- 19 ms vs 16 +/- 7 ms, respectively, all p < 0.05). rMSSD (the square root of the mean of the squared differences between adjacent normal RR intervals over the entire ECG recording) and pNN50 (percentage of differences between adjacent normal RR intervals that are greater than 50 ms computed over the entire ECG recording) were also higher in Group A patients, with borderline significance. All measurements of total frequency and low-frequency and high-frequency components tended to be higher in Group A than Group B, but this was only significant for total frequency amplitude (22.9 +/- 13.4 ms vs 10.9 +/- 6.1 ms, p < 0.05). Dopamine but not dobutamine treatment seems to restore the depressed circadian change in frequency-domain HRV classically seen in patients with CHF. The HRV change during head-up tilting did not differ between the two groups. Three patients in Group B showed non-sustained ventricular tachycardia on ambulatory ECG during the treatment period. CONCLUSIONS: Dopamine and dobutamine have comparable therapeutic effects in patients with CHF, but low-dose dopamine more favorably affects cardiac autonomic function.

Aged↗

PubMed1998

Prediction of right ventricular infarction from standard surface ECG in patients with inferior myocardial infarction.

BACKGROUND: Patients with inferior myocardial infarction (MI) have a 45% chance of having concurrent right ventricular infarction (RVI); of these, 5-10% suffer hemodynamic collapse. Immediate correct diagnosis and appropriate management of such patients is vital. ST-segment elevation in the right precordial V4 lead (V4R) has a high diagnostic value in identifying RVI, but this determination requires additional time and cost. An attempt was made to use a collection of patients' standard surface electrocardiograms (ECG) to find any available data to detect RVI and to lead to a new way to diagnose RVI. METHODS: Fifty patients (males/females, 44/6; mean age, 64.3 +/- 6.9 years) with acute inferior myocardial infarction were enrolled in a first group to develop new diagnostic criteria for RVI. As a first step, the ST-segment change in every standard surface ECG lead was analyzed and compared with corresponding changes in V4R. RVI was diagnosed by typical clinical symptoms (chest pain for more than 30 minutes, ST elevation > 0.1 mV and enzyme changes) accompanying ST elevation of more than 0.1 mV in V4R (by Lopez-Sendon criteria) and echocardiographic findings. RVI was diagnosed in 24 (48%) patients using ECG. The new criteria were then tested in a secondary group of 48 patients (males/females, 43/5; mean age, 65.5 +/- 7.9 years) with inferior MI. RESULTS: Analysis of these patients found that ST depression in lead I and aVL was a specific characteristic of RVI (I + aVL > 0.2 mV). This criterion was applied to another group of patients with acute inferior MI to check the predictive value (sensitivity, 94.7%; specificity, 89.7%; positive predictive value, 85.7%; negative predictive value, 96.3%). CONCLUSIONS: In patients with evolving inferior MI, standard surface ECG analyzed for this criterion could aid clinical recognition of concomitant RVI.

Aged↗

PubMed1998

Successful pregnancy in a woman with acute myeloid leukemia treated with high-dose whole-body irradiation.

BACKGROUND: Although radiotherapy is an integral part of managing certain types of hematologic malignancies, its effect on the reproductive system are well established. We report a case of successful pregnancy in a patient who received high-dose whole-body irradiation (WBI) (1,575 cGy) as part of her treatment for acute myeloid leukemia (AML). CASE: A 26-year-old woman received high-dose cyclophosphamide accompanied by high-dose (1,575 cGy) WBI as part of her treatment for AML when she was 23 years of age. The patient received oral contraceptives before, during and after treatment. After WBI, the patient developed ovarian failure and amenorrhea, which was confirmed by hormonal evaluation. The amenorrhea persisted for one year. No recurrence of AML was found. The patient was placed on hormone replacement therapy (HRT) because of vasomotor changes. An unexpected pregnancy occurred 14 months later; HRT was discontinued. The patient delivered a normal female infant at 38 weeks of gestation. The infant was followed for eight months; her development appeared to be normal. CONCLUSION: In this case report, it is unclear whether pregnancy resulted from active folliculogenesis remote from radiation therapy or from possible ovarian protection rendered by the use of oral contraceptives. The benefit of oral contraceptives in protecting the ovary from radiation injury is unknown and remains an area for future research.

Adult↗

PubMed1998

A case of severe hyperammonemia and unconsciousness following sodium valproate intoxication.

Although valproic acid has gradually gained its popularity in the treatment of various seizure disorders, overdose of valproate is not common. An 18-y-old man with a history of epilepsy controlled by sodium valproate and clonazepam attempted suicide with an ingestion of 45 g sodium valproate. He presented to our service with drowsiness and irritability. Extremely high serum ammonia (623 ug/dL) and elevated serum valproate concentration (575 ug/mL) were found on admission. Several metabolic abnormalities, including hypernatremia, hypocalcemia and metabolic acidosis, as well as, increased serum transaminase levels were also recorded. With supportive measures, he became clear 24 h later and was discharged 6 d after ingestion. Serial follow-up of his serum valproate and ammonia levels disclosed a close relationship between these 2 measurables. After acute overdose of valproic acid, patients usually present with mild and generally reversible depression of the central nervous system. However, impairment of liver function, hyperammonemia, fluid-electrolyte disturbances, coma, seizures, hypotension and even death may occur following valproate overdose. Symptomatic and supportive measures are the mainstay in the treatment of valproic acid overdose. With prompt diagnosis and early institution of treatment, a complete recovery should be anticipated.

Adolescent↗

PubMed1998

Uterine myoma after cessation of gonadotropin-releasing hormone agonist: ultrasound and histopathologic findings.

BACKGROUND: This study attempted to search for the possible mechanism of regrowth of uterine myoma after cessation of gonadotropin-releasing hormone agonist (GnRHa) therapy. METHODS: Five premenopausal women presenting with symptomatic uterine myoma were prospectively studied in this trial. All patients were treated with a subcutaneous injection of goserelin depot 3.6 mg every four weeks for 16 weeks. Clinical examinations as well as hormonal and ultrasound determinations were performed before, during and after treatment to monitor the efficacy of therapy. At the end of the treatment period, all patients underwent myomectomy. The ultrastructural change of the myoma was evaluated postoperatively. RESULTS: The volume of the uterus decreased 21-57% and the volume of the uterine myoma decreased 21-65% after therapy. There was no significant change in resistance index of the uterine vessels or major vessels supplying the uterine myoma between pretreatment and post-treatment values. The morphologic features of the treated myoma showed marked cellular shrinkage and loss of myofibrillar structure. CONCLUSIONS: There is no significant cellular damage to the cellular structure that contributes to regrowth of treated intramural uterine myoma following cessation of treatment.

Antineoplastic Agents, Hormonal↗

PubMed1997

Fluorescence probing of yeast actin subdomain 3/4 hydrophobic loop 262-274. Actin-actin and actin-myosin interactions in actin filaments.

Residues 262-274 form a loop between subdomains 3 and 4 of actin. This loop may play an important role in actin filament formation and stabilization. To assess directly the behavior of this loop, we mutated Ser265 of yeast actin to cysteine (S265C) and created another mutant (S265C/C374A) by changing Cys374 of S265C actin to alanine. These changes allowed us to attach a pyrene maleimide stoichiometrically to either Cys374 or Cys265. These mutations had no detectable effects on the protease susceptibility, intrinsic ATPase activity, and thermal stability of labeled or unlabeled G-actin. The presence of the loop cysteine, either labeled or unlabeled, did not affect the actin-activated S1 ATPase activity or the in vitro motility of the actin. Both mutant actins, either labeled or unlabeled, nucleated filament formation considerably faster than wild-type (WT) actin, although the critical concentration was not affected. Whereas the fluorescence of the C-terminal (WT) probe increased during polymerization, that of the loop (S265C/C374A) probe decreased, and the fluorescence of the doubly labeled actin (S265C) was approximately 50% less than the sum of the fluorescence of the individual fluorophores. Quenching was also observed in copolymers of labeled WT and S265C/C374A actins. An excimer peak was present in the emission spectrum of labeled S265C F-actin and in the labeled S265C/C374A-WT actin copolymers. These results show that in the filaments, the C-terminal pyrene of a substantial fraction of monomers directly interacts with the loop pyrene of neighboring monomers, bringing the two cysteine sulfurs to within 18 A of one another. Finally, when bound to labeled S265C/C374A F-actin, myosin S1, but not tropomyosin, caused an increase in fluorescence of the loop probe. Both proteins had no effect on excimer fluorescence. These results help establish the orientation of monomers in F-actin and show that the binding of S1 to actin subdomains 1 and 2 affects the environment of the loop between subdomains 3 and 4.

Actins↗

PubMed1997

Effects of short-term treatment of nicorandil on exercise-induced myocardial ischemia and abnormal cardiac autonomic activity in microvascular angina.

The underlying mechanisms of myocardial ischemia in microvascular angina may include endothelial dysfunction, abnormal smooth muscle tone, and abnormal autonomic control of coronary microvasculatures. This randomized, double-blind, placebo-controlled, crossover study was conducted to evaluate the effect of nicorandil (a nitrate-potassium channel opener) therapy on exercise-induced myocardial ischemia and cardiac autonomic activity in 13 patients with microvascular angina. After a 2-week placebo run-in period, patients were randomly assigned to the first 2-week treatment with nicorandil 5 mg tid or placebo, then crossed over to the second 2-week treatment after a 2-week washout period. Treadmill exercise tests and 24-hour ambulatory electrocardiogram monitoring were performed at the end of each treatment phase. The results showed that both time to 1-mm ST depression and total exercise duration were significantly prolonged with nicorandil treatment compared with placebo (p = 0.026 and 0.036, respectively). Maximum exercise ST depression also tended to be less with nicorandil treatment than with placebo (p = 0.083). Compared with 10 healthy control subjects, study patients had significantly reduced heart rate variability in both low- and high-frequency bands while receiving placebo. Nicorandil treatment did not change the altered heart rate variability in either time domain or spectral analysis. Systemic hemodynamics were also unchanged with nicorandil treatment. Thus, 2-week oral nicorandil therapy moderately improved exercise-induced myocardial ischemia without modifying the already altered cardiac autonomic activity, suggesting that nicorandil might have a direct vasodilatory effect on coronary microvasculatures in patients with microvascular angina.

Administration, Oral↗

PubMed1997

Selective intra-arterial calcium injection in the investigation of adult nesidioblastosis: a case report.

A 69-year-old man with recurrent hypoglycaemia had inappropriately elevated plasma insulin level during a symptomatic hypoglycaemia, but had a negative prolonged fast. Computerized tomography (CT) of the abdomen revealed a nodular lesion over the body of pancreas, whereas pancreatic arteriography failed to show tumour blush. Hence, arterial stimulation (with calcium) and venous sampling (ASVS) was performed and a brisk response of plasma insulin level was found when calcium was injected both into the splenic and the superior mesenteric arteries. Since no tumour was found during the operation, the patient received subtotal distal pancreatectomy. Pathological examination of the resected tissue disclosed a typical finding of nesidioblastosis. We suggest that selective intra-arterial calcium injection with hepatic venous sampling for insulin gradients is useful for the diagnosis of adult nesidioblastosis.

Aged↗

PubMed1997

Port site metastasis after laparoscopic-assisted vaginal hysterectomy for endometrial cancer: possible mechanisms and prevention.

Only 19 cases of metastases at the cannula insertion site after laparoscopy for gynecological malignancy have been reported in the literature. One case has been diagnosed with cervical squamous cell carcinoma, whereas the others have been diagnosed with ovarian cancer and borderline ovarian tumor. We present a novel case of laparoscopy-site abdominal wall metastasis from endometrial cancer after laparoscopic-assisted vaginal hysterectomy (LAVH). The 56-year-old female patient exhibited metastases of an abdominal wall trocar site and a perineal site after undergoing LAVH and laparoscopic-assisted (LA) bilateral pelvic lymph node sampling as well as LA para-aortic lymph node sampling for treating endometrial carcinoma, surgical staging IIIC, G3. The interval between the surgical extirpation of endometrial carcinoma and diagnosis of the tumor recurrence was 6 months, suggesting that overmanipulation of the diseased organ during laparoscopic surgery may have resulted in tumor spillage, intraperitoneal dissemination, and wound contamination. Although this procedure has been proven beneficial to patients with benign disease or early-stage gynecologic malignancies, laparoscopic-assisted vaginal hysterectomy may not be efficacious to eradicate advanced gynecological malignancy.

Abdominal Muscles↗

PubMed1997

MRI of the fornix and mamillary body in temporal lobe epilepsy.

We performed MRI on 27 patients with clinically proven temporal lobe epilepsy (TLE), all with prior EEG lateralisation, and 10 volunteers, studied to evaluate disparity in size arising from biological variation (group 1). Three-dimensional spoiled GRASS (3DSPGR) sequences provided 2-mm contiguous sections of the limbic system, enabling assessment of the hippocampus (HC), fornix (FN) and mamillary body (MB). Measurements of FN and MB width were made from a workstation. Any percentage difference in size was computed. In 19 cases there was unilateral abnormality in the HC (group 2); in 18 and 19 cases respectively there was a smaller FN and MB on the same side as the abnormal HC. This percentage difference in size was significantly greater than that in group 1 in the FN and MB in 17 and 17 cases respectively. Comparison of percentage difference computations for FN and MB between groups 1 and 2 showed high statistical significance (P < 0.0002). In 5 patients with clinical TLE the HC was normal on MRI (group 3). Unequal FN and MB sizes were found in 4, significant in 2. Comparison of percentage difference computations for FN and MB showed statistical significance (P < 0.0005 and P < 0.0003 respectively). There was no case of discordance between the sides of hippocampal abnormality and the smaller FN or MB or between the sides of smaller FN and MB. The strong concordance between the changes in the HC and those in the FN and MB suggests that this combination will play an important role in the assessment of TLE and limbic system abnormality.

Adolescent↗

PubMed1997

Dosimetric parameters of enhanced dynamic wedge for treatment planning and verification.

Treatment planning for Enhanced Dynamic Wedge requires a knowledge of the dosimetric parameters of the treatment fields. These dosimetric parameters include depth doses, surface doses, buildup doses, peripheral doses, beam profiles, wedge angles and wedge factors. These parameters and their application to treatment planning are evaluated and compared with standard open field and metal wedge field dosimetric parameters.

Particle Accelerators↗

PubMed1997

Malfunction of an active fixation J-shaped screw-in atrial electrode lead: a case report.

Active fixation leads, using active grasping devices, ensure good postoperative lead fixation, long-term performance, and make possible later lead removal on demand. However, these delicate designs have not been without practical difficulties. We present two cases of fixation stylet fracture during helix extension and retraction maneuver respectively with resultant lead inoperability and abandonment. The fixed leads could be removed by torquing the entire lead counterclockwise.

Adult↗

PubMed1997

Efficacy and safety of fenofibrate or gemfibrozil on serum lipid profiles in Chinese patients with type IIb hyperlipidemia: a single-blind, randomized, and cross-over study.

BACKGROUND: The purpose of the study was to evaluate the effects and safety of fenofibrate or gemfibrozil on plasma lipid profiles in Chinese patients with type IIb hyperlipidemia. METHODS: Patients with previously diagnosed type IIb hyperlipidemia were initially evaluated in this single-blind, randomized, cross-over study. Only those who had persistent hyperlipidemia after a two-month diet control period were included. The patients were randomized to either fenofibrate 100 mg tid or gemfibrozil 600 mg bid for three months, then shifted to alternate drug for another three months after a two-month washout period. During the whole 10-month period, a prudent diet was maintained. Each patient was followed up at Out-patient Clinic regularly for diet interview, compliance and possible adverse events. RESULTS: A total of 12 patients, 11 males and 1 female, completed the whole study. After a three-month treatment of fenofibrate, there was significant reduction in plasma total cholesterol (22.7%, p < 0.001), total triglycerides (43.2%, p < 0.001), and low-density lipoprotein (LDL)-cholesterol (25.7%, p = 0.001). Serum high density lipoprotein (HDL) cholesterol was also increased by 30.2% (p = 0.055). On the other hand, only total triglyceride was significantly reduced by 36.5% (p = 0.005) with gemfibrozil treatment. There was no significant change of serum total, HDL- and LDL-cholesterol after the three-month treatment of gemfibrozil. Besides, serum uric acid and alkaline phosphatase were significantly reduced with fenofibrate but not with gemfibrozil treatment. There was no obvious adverse event noted during each treatment period with either drug. CONCLUSIONS: The findings suggest that in Chinese patients with type IIb hyperlipidemia, both fenofibrate and gemfibrozil can safely and significantly reduce serum triglyceride. Fenofibrate, but not gemfibrozil, could also reduce serum total cholesterol, LDL and uric acid. The results were compatible with the findings of previous studies in western patients with hyperlipidemia.

Adult↗

PubMed1997

Severe bleeding from a pregnancy tumor. A case report.

BACKGROUND: Hyperplastic gingivitis and gingival hyperplasia accompanying gestation have been termed "pregnancy gingivitis" and "pregnancy tumor." The condition is benign but, rarely, is complicated by severe bleeding that is difficult to manage. A single case of a pregnancy tumor is reported. CASE: A 28-year-old woman in the third trimester was evaluated for treatment of a pregnancy granuloma with recurrent episodes of severe bleeding for two weeks. Conservative management by firm pressure on gauze packs was applied to control the bleeding, but in vain. Induction of labor was conducted at 37 weeks partially because of term pregnancy and uncontrollable bleeding from the gingiva. An emergency cesarean section was done because of acute fetal distress during induction of labor. A healthy infant was delivered. The gingival bleeding stopped spontaneously five days afterwards. The patient was given thorough dental prophylaxis and oral hygiene instructions. The buccal granulomatous tumor was decreased in size four weeks postpartum. CONCLUSION: Careful oral dental hygiene, removal of dental plaque and debris, and use of soft toothbrushes are important during pregnancy to avoid occurrence of a pregnancy tumor. If uncontrolled bleeding occurs, management should be based on the individual condition and should range from supportive therapy--such as desiccation of bleeders; local, firm compression and oral hygiene to blood transfusion--as well as medication to accelerate fetal lung maturity or even termination of pregnancy to save the patient's life, as with treatment of uncontrollable eclampsia.

Adult↗

PubMed1997

Acetaminophen poisoning in late pregnancy. A case report.

BACKGROUND: Acetaminophen poisoning is a major cause of hospital admission and has been extensively reviewed. Its occurrence in pregnant women has been reported seldom, and the prognosis has been good except for one case, in which the fetus died. We report on a case of acetaminophen poisoning that resulted in the death of both the mother and the infant. CASE: A 38-year-old woman whose pregnancy was at 31 weeks' gestational age was evaluated for treatment of an acetaminophen overdose. She was admitted more than 26 hours after taking 35 g of acetaminophen. An emergency cesarean section was performed one hour after admission because of acute fetal distress. A grossly normal, 1,620-g, female infant was delivered and had Apgar scores at 1, 5 and 10 minutes of 0, 0 and 1, respectively, despite the initiation of resuscitation immediately following delivery. Acidosis was noted in the mother during the operation; it was followed by acute hepatorenal failure 16 hours after admission. That resulted in the mother's death 40 hours after admission. The infant also died 34 hours after delivery. CONCLUSION: Delays in administering the antidote treatment, N-acetylcysteine, after acetaminophen intoxication significantly increase the risk of mortality in both the mother and infant. The development of acidosis carries a poor prognosis in such patients and may necessitate liver transplantation to save the life of the mother.

Acetaminophen↗

PubMed1997

Refractory seizures in a young army cohort.

This survey covered male Singapore citizens born in 1974 who were medically screened at the age of 18 years before enlistment for compulsory military service. Suspected epileptics were referred to government hospitals for further management. Out of 20,542 men, there were 121 epileptics, giving a cumulative incidence of 5 per 1000 by age 18 years. We had information on 106 (87%) of these individuals and were able to interview them and review their hospital records. Seventy-three of the 106 (69%) epileptics had generalised seizures while 14 (13%) had refractory seizures. There was no statistically significant racial bias amongst these epileptics. Unprovoked afebrile seizures occurred early in these patients, half of whom had seizures onset before 7 years of age. Nine refractory epileptics had a history of febrile seizures, 4 of which were complex febrile seizures. Magnetic resonance imaging identified mesial temporal sclerosis in 2 patients and a hypothalamic lesion in 1 patient. Computed tomographic scans revealed focal cortical atrophy in 2 patients. Nine other patients had normal imaging studies. Nine out of 14 (64%) patients with refractory epilepsy had partial seizures; 4 (29%) had generalised seizures and 1 (7%) was unclassified. This is in contrast to the distribution of the entire cohort of epileptics studied. Two out of 9 patients with refractory partial seizures (gelastic epilepsy and mesial temporal sclerosis) had undergone surgery while 6 of the other 7 patients refused to consider surgery.

Adolescent↗

PubMed1997

Trifascicular block with intermittent complete atrioventricular block in a child.

Trifascicular block, which consists of impaired conduction in the three main fascicles of the ventricular conduction system, may progress to high-grade or complete atrioventricular block. It rarely occurs in children with a structurally normal heart. We report a case of trifascicular block in a previously healthy 9-year-old girl. The patient presented with repetitive seizures. The electrocardiogram showed a complete right bundle branch block, left axis deviation, PR interval prolongation, and intermittent high-degree and complete atrioventricular block. She was successfully treated with a temporary pacemaker and her electrocardiogram returned to a normal sinus rhythm in 3 days. She has remained well over a 4-year follow-up. Although her cardiac enzyme levels were normal, the clinical course and electrocardiography findings suggested myocarditis. We emphasize the diagnosis of trifascicular block using electrocardiography; clinical outcome is good, if the patient is managed properly.

Child↗

PubMed1996

Effect of naftifine on neutrophil adhesion.

Effective methods of fungal treatment involve reduction in fungal infections and host inflammatory responses. Naftifine (NF), a topical antifungal agent, is highly active in vitro and in vivo against a wide range of pathogenic fungi. Additionally NF has been shown to inhibit polymorphonuclear leukocyte (PMN) chemotaxis and respiratory burst activity in an irreversible dose-dependent and time-dependent manner. Since leukocyte adherence to endothelia is believed to be one of the initial crucial events in the recruitment of circulating leukocytes to the site of inflammation, we have investigated the in vitro effect of NF on PMN adherence to nylon fiber, BSA-coated glass chamber or polystyrene, and endothelial monolayers via three adherence assays. All three assays demonstrated a statistically significant reduction (p < 0.01-0.001) in PMN adherence to the respective media. In particular, NF (at 30-60 micrograms/ml) significantly inhibited PMN adherence to endothelial monolayers (p < 0.01) as measured spectrophotometrically by the uptake of rose bengal stain. Therefore, NF inhibits PMN adherence to endothelia in our in vitro model system. This inhibition may constitute part of the anti-inflammatory effect of NF.

Allylamine↗