Biomedical subjects

J C Lam

Publications and source records attributed to J C Lam.

7 recordsLinked to original sources

PubMed2001

Follow-up survey of children and adolescents with chest pain.

BACKGROUND: The purposes of this study were to identify the outcome of chest pain in children and to identify the incidence of recurrent chest pain and the need for further medical services. METHODS: A telephone survey was conducted of pediatric patients evaluated in the cardiology clinic for chest pain. RESULTS: In the majority of patients (53 of 55), chest pain was thought to be noncardiac in origin. Fifteen patients were offered therapy, and all followed the therapy. Most (10 of 15) thought the therapy was helpful. Forty-one (75%) were satisfied with the explanation given to them. Twenty-six had recurrent chest pain, 12 had pain that was severe, 13 thought the pain interfered with daily activities, and 10 sought further medical care. With the secondary evaluation of chest pain, the diagnosis changed in 9 of 10 cases. CONCLUSION: Chest pain in children is generally benign. However, chest pain can be recurrent and severe, interfering with activities of daily life.

Adolescent↗

PubMed2000

Haplotype fine mapping by evolutionary trees.

To refine the location of a disease gene within the bounds provided by linkage analysis, many scientists use the pattern of linkage disequilibrium between the disease allele and alleles at nearby markers. We describe a method that seeks to refine location by analysis of "disease" and "normal" haplotypes, thereby using multivariate information about linkage disequilibrium. Under the assumption that the disease mutation occurs in a specific gap between adjacent markers, the method first combines parsimony and likelihood to build an evolutionary tree of disease haplotypes, with each node (haplotype) separated, by a single mutational or recombinational step, from its parent. If required, latent nodes (unobserved haplotypes) are incorporated to complete the tree. Once the tree is built, its likelihood is computed from probabilities of mutation and recombination. When each gap between adjacent markers is evaluated in this fashion and these results are combined with prior information, they yield a posterior probability distribution to guide the search for the disease mutation. We show, by evolutionary simulations, that an implementation of these methods, called "FineMap," yields substantial refinement and excellent coverage for the true location of the disease mutation. Moreover, by analysis of hereditary hemochromatosis haplotypes, we show that FineMap can be robust to genetic heterogeneity.

Algorithms↗

PubMed2000

Domestic violence.

Domestic violence is alarmingly prevalent, yet medical students, residents, and experienced physicians are often handicapped by insufficient knowledge and expertise in the diagnosis and care of these patients. This article reviews the epidemiology of domestic violence, highlights risk factors, discusses current obstacles in the diagnosis and treatment of domestic violence, identifies history taking and physical examination skills to increase diagnosis of this condition, and outlines treatment plans for victims.

Adolescent↗

PubMed1998

Activation of the Ah receptor signal transduction pathway by bilirubin and biliverdin.

The aryl hydrocarbon receptor (AhR) is a ligand-dependent transcription factor that mediates many of the biological and toxicological actions of 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD, dioxin) and related chemicals. Although no endogenous physiological ligand for the AhR has yet been described, persistent expression of hepatic CYP1A1 gene expression (an AhR-dependent response) in congenitally jaundiced Gunn rats indirectly supports the existence of such a ligand(s) in these animals. High plasma levels of the heme degradation product bilirubin (BR) in these animals prompted us to evaluate whether BR is an endogenous AhR agonist. Expression of dioxin responsive element (DRE)-driven luciferase gene expression in stably transfected mouse, guinea pig, rat, and human cells was induced by treatment with physiological concentrations of BR. Biliverdin (BV), the metabolic precursor of bilirubin, also induced luciferase activity in all species. BR and BV not only stimulated AhR transformation and DRE binding in vitro andin cells in culture, but competitive inhibition of [3H]TCDD-specific binding to the cytosolic AhR revealed that these chemicals are AhR ligands. The significantly greater inducing potency of these chemicals in intact cells, compared to their ligand binding and AhR transformation potency in vitro, suggests that BR and BV may also be converted within the cell to a more potent activator(s). Our results demonstrate that the heme degradation products BR and BV are AhR ligands which can regulate the AhR-dependent gene expression pathway.

Animals↗

PubMed1995

Measurement of irradiated small bowel volume in pelvic irradiation and the effect of a bellyboard.

From June 1992 to January 1993, 51 consecutive patients with pelvic cancers treated with radiotherapy alone, or surgery plus post-operative radiotherapy, were included in a study of the effectiveness of a false table-top (bellyboard) in displacing small bowel loops out of anteriorposterior (AP) and posterioranterior (PA) opposing pelvic fields. The small bowel was opacified with barium. The volume of small bowel within the radiotherapy fields in the prone position with a bellyboard was reduced by 134-300 ml (29%-61%) when compared with that in supine position, and by 136-216 ml (28%-50%) when compared with that in prone position without a bellyboard, depending on the type of previous surgical procedures. The differences were highly statistically significant and likely to be clinically significant. The bellyboard we used is simple, economical, convenient and well tolerated. Its use is recommended, especially when AP and PA pelvic fields are used.

Adult↗

PubMed1985

Comparative diagnostic value of exercise polarcardiography and 14-lead electrocardiography in the detection of coronary artery disease.

Early postexercise polarcardiographic (PCG) changes in the ST segment vector, as reflected in the variable MS X theta, are reported to clearly distinguish normal subjects from those with myocardial ischemia. We prospectively assessed the value of this test in detecting coronary artery disease (CAD) during treadmill exercise in 178 patients within 1 week of diagnostic coronary angiography. The average postexercise MS X theta was 16.9 +/- 9.7 mV degrees in patients with CAD, whereas it was 16.2 +/- 10.2 mV degrees in patients with CAD (p = NS). The optimal ratio of sensitivity to specificity, using different normal-abnormal cutoff values, was 57% and 56%, respectively, for a delineating MS X theta value of 12. The sensitivity and specificity of a simultaneously recorded 14-lead ECG using the criterion of exercise-induced horizontal downsloping ST segment depression greater than or equal to 0.1 mV, was 71% and 78%, respectively. The PCG results were not improved by analyzing MS X theta during exercise, or by analyzing the difference in MS X theta between rest and exercise or rest and postexercise. The sensitivity of the PCG for multivessel or left anterior descending CAD was higher than for less severe forms of CAD, but was significantly less sensitive than the 14-lead exercise ECG (70% versus 84%; p = 0.02; and 62% versus 75%; p = 0.05, respectively). Thus, exercise polarcardiography, as employed in the present study, does not improve the diagnostic content of the 14-lead exercise ECG. Contrary to previous reports, there is no clear separation of normal from abnormal MS X theta values when a prospective series of patients is tested.

Coronary Disease↗

PubMedDate not supplied

Initial experience with octreotide in the pediatric population.

Octreotide is a somatostatin analogue that has been suggested as a therapeutic agent in various diverse disease processes including gastrointestinal bleeding, pancreatitis, hypoglycemia related to hyperinsulin states, and chylous peritoneum/thorax. Despite successful use in the adult population, there is limited information concerning its use in pediatric patients. The authors retrospectively review their experience with octreotide in 10 infants and children ranging in age from 14 days to 17 years. Octreotide, administered by continuous intravenous infusion or intermittent bolus dosing, was used in the treatment of gastrointestinal bleeding in four patients, pancreatitis in three patients, chylous leaks in two patients, and hypoglycemia related to nesidioblastosis in one patient. The clinical course of these patients and the potential therapeutic impact of octreotide are evaluated. Additionally, previous experiences with octreotide in pediatric patients, dosing regimens, and the potential role of the drug in other disease processes are discussed.

Adolescent↗