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Biomedical subjects

E Chuang

Publications and source records attributed to E Chuang.

27 records · Page 2Linked to original sources
PubMed1995

Intravenous sedation in pediatric upper gastrointestinal endoscopy.

To assess the safety and efficacy of intravenous sedation in pediatric upper endoscopy, all elective outpatient procedures performed during a 2-year period (January 1, 1991 through December 31, 1992) were retrospectively reviewed. Of 614 children, 553 received intravenous meperidine and midazolam; 61 received fentanyl and midazolam. The mean dose of meperidine was 1.5 +/- 0.7 mg/kg and of fentanyl 0.0031 +/- 0.0014 mg/kg. Less midazolam was needed for children receiving fentanyl than for those receiving meperidine (0.05 +/- 0.03 mg/kg versus 0.08 +/- 0.05 mg/kg, p < 002). Recovery time (minutes) was shorter for those receiving fentanyl (74.7 +/- 22.8 versus 95.1 +/- 23.0, p < .003). Side effects occurred in 117 patients (19.1%), of which the majority were mild (83%); all were transient with no residual sequelae. Inability to complete the procedure occurred in fewer than 1%. We conclude that both combinations of medication are safe and effective for children of all ages. The use of fentanyl/midazolam results in a shorter recovery time and a lower dose of midazolam.

Adjuvants, Anesthesia↗
PubMed1995

High levels of glucose-6-phosphatase gene and protein expression reflect an adaptive response in proliferating liver and diabetes.

The regenerating liver after partial hepatectomy is one of the few physiologic models of cellular proliferation in the adult animal. During hepatic regeneration, the animal is able to maintain metabolic homeostasis despite the acute loss of two thirds of hepatic tissue. In examining the molecular mechanisms regulating hepatic regeneration, we isolated novel immediate-early genes that are rapidly induced as the remnant liver undergoes the transition from its normal quiescent state into the G1 phase of the cell cycle. One of the most rapidly and highly induced genes which we initially termed RL-1, encodes rat glucose-6-phosphatase (rG6Pase). G6Pase mRNA peaks at 30 min and 36-48 h after hepatectomy correlating with the first and second rounds of cell division. This finding is compatible with studies that showed that G6Pase enzyme activity increases during liver regeneration. However, the increase in G6Pase mRNA is much more dramatic, indicating that it is a more sensitive indicator of this regulation. G6Pase gene expression peaks in the perinatal time period in the liver and remains elevated during the first month of life. The expression of the G6Pase gene is also dramatically elevated in BB diabetic rats, again higher than the enzyme elevation, and its relative induction after partial hepatectomy is blunted in these animals. Insulin treatment of partially hepatectomized diabetic animals downregulates the expression of G6Pase mRNA. Using specific antibodies against G6Pase, we detect a 36-kD G6Pase protein, and its level is elevated in regenerating and diabetic livers. The pattern of G6Pase mRNA expression appears to reflect similar changes in insulin and glucagon levels which accompany diabetes and hepatic proliferation. The elevation of G6Pase expression in these conditions is indicative of its importance as a regulator of glucose homeostasis in normal and abnormal physiologic states.

3T3 Cells↗
PubMed1994

Differential induction of Fos protein and a Fos-related antigen following acute and repeated cocaine administration.

The present study examined the effects of a single and five once daily injections of cocaine on the expression of c-fos mRNA, Fos protein and Fos-related antigens (Fra) in the striatum. A single injection (40 mg/kg, i.p.), which induces locomotion, increased the expression of c-fos mRNA, Fos protein and a 35 kDa Fra. In contrast, five injections (40 mg/kg, i.p.) given once a day, which induces even more behavioral stimulation, diminished the increase in c-fos mRNA and Fos protein expression. However, the cocaine-induced Fra expression was sustained and not reduced after the five injections. The results demonstrate that cocaine-induced expression of the Fos/Fra gene family is dynamic and the profile of gene transcription and translation in the striatum changes when animals are behaviorally more sensitive to cocaine.

Animals↗
PubMed1994

Critical binding and regulatory interactions between Ras and Raf occur through a small, stable N-terminal domain of Raf and specific Ras effector residues.

Genetic and biochemical evidence suggests that the Ras protooncogene product regulates the activation of the Raf kinase pathway, leading to the proposal that Raf is a direct mitogenic effector of activated Ras. Here we report the use of a novel competition assay to measure in vitro the relative affinity of the c-Raf-1 regulatory region for Ras-GTP, Ras-GDP, and 10 oncogenic and effector mutant Ras proteins. c-Raf-1 associates with normal Ras and the oncogenic V12 and L61 forms of Ras with equal affinity. The moderately transforming mutant Ras[E30K31] also bound to the c-Raf-1 regulatory region with normal affinity. Transformation-defective Ras effector mutants Ras[N33], Ras[S35], and Ras[N38] bound poorly. In contrast, the transformation defective Ras[G26I27] and Ras[E45] mutants bound to the c-Raf-1 regulatory region with nearly wild-type affinity. A stable, high-affinity Ras-binding region of c-Raf-1 was mapped to a 99-amino-acid subfragment of the first 257 residues. The smallest Ras-binding region identified consisted of N-terminal residues 51 to 131, although stable expression of the domain and high-affinity binding were improved by the presence of residues 132 to 149. Deletion of the Raf zinc finger region did not reduce Ras-binding affinity, while removal of the first 50 amino acids greatly increased affinity. Phosphorylation of Raf[1-149] by protein kinase A on serine 43 resulted in significant inhibiton of Ras binding. demonstrating that the mechanism of cyclic AMP downregulation results through structural changes occurring exclusively in this small Ras-binding domain.

Cyclic AMP-Dependent Protein Kinases↗
PubMed1993

Interferon alfa-2a in the treatment of exudative age-related macular degeneration.

Nineteen patients (20 eyes) with the exudative form of macular degeneration were treated with parenteral interferon alfa-2a. Fifteen patients (16 eyes) had adequate follow-up for evaluation of outcome of the exudative macular lesion. The average follow-up was 8 months (range 5-11 months). Color photographs and fluorescein angiograms were evaluated independently by two masked readers for change in size, presence of fibrosis, and leakage of the neovascular lesion. During the follow-up, none of the exudative lesions resolved: one lesion became smaller, four remained the same, nine enlarged, and two could not be graded based on the photographs. Visual acuity remained 20/40 or better in four eyes. The proportion of eyes with visual acuity of 20/200 or worse increased from 35% at the initial visit to 59% at the final visit. Ten patients experienced significant but reversible side effects, including weight loss, depression, and/or hematopoietic suppression. The data from these cases do not support any significant treatment benefit from interferon alfa-2a at the doses used in exudative macular degeneration.

Aged↗
PubMedDate not supplied

Autoimmune liver disease and sickle cell anemia in children: a report of three cases.

PURPOSE: We wish to alert clinicians to the possible association between Sickle cell anemia (SCA) and autoimmune liver disease (AIL). METHODS: AIL was diagnosed by serologic, histologic and/or cholangiographic studies in patients with known SCA. RESULTS: Three schoolaged children with SCA were investigated for increased levels of transaminases and/or worsening jaundice. All were diagnosed to have AIL. Two patients had autoimmune hepatitis and have responded to immunosuppressive therapy, and I had primary sclerosing cholangitis and is stable with therapy. CONCLUSIONS: Autoimmune hepatitis and sclerosing cholangitis are rare liver disorders of childhood, but may occur with greater frequency in patients with SCA. Early diagnosis and treatment is essential to prevent progression to liver cirrhosis. This association may provide a clue to the etiology of AIL and warrants further investigation.

Adolescent↗