Biomedical subjects

L L Lai

Publications and source records attributed to L L Lai.

9 recordsLinked to original sources

PubMed2001

Clinical and cost effectiveness of a new hepatocellular MRI contrast agent, mangafodipir trisodium, in the preoperative assessment of liver resectability.

BACKGROUND: Improved preoperative assessment of focal liver disease and tumors could have a potentially significant impact on their treatment. Mangafodipir trisodium (Teslascan; Nycomed Amersham Imaging, Little Chalfont, UK) is a new hepatocellular contrast agent for use with state-of-the-art MR imaging that, in early reports, is accurate in detection and characterization of liver lesions. METHODS: Records and diagnostic images of all patients undergoing enhanced Teslascan MRI (T-MRI) at our institution were reviewed. We assessed the relative sensitivities of contrast-enhanced CT scan (CECT) and T-MRI in detecting lesions, as well as the impact of T-MRI in the decision to operate or not on patients. In those patients taken to surgery, the correlation between T-MRI and intraoperative palpation and intraoperative ultrasound (IOUS) was determined. RESULTS: Fifty-four patients were noted on CECT to have focal liver lesions and subsequently underwent imaging with T-MRI. The T-MRI correlated with CT findings in 22 patients (41%), upstaged the liver disease in 26, and demonstrated fewer lesions in 6. Only 43 patients were considered operative candidates and T-MRI influenced the operative decision in 32 patients (74%), dissuading operative intervention in 14. In the 25 patients without clear preoperative evidence of unresectability who were taken to the operating room, T-MRI correlated with findings of intraoperative palpation in 19 (76%). In the 20 patients who underwent IOUS, T-MRI correlated with IOUS in 14 patients (70%). IOUS detected an additional nine lesions, all of which were <1 cm. Seventeen patients underwent resection and/or ablation of their liver lesions. Compared with pathology, sensitivities of CECT, T-MRI, and intraoperative evaluation were 61%, 83%, and 93%, respectively. T-MRI failed to predict hepatic-specific unresectability in only one of eight patients, the other seven having extrahepatic disease. CONCLUSIONS: These findings suggest that T-MRI is more sensitive than CECT in the preoperative predicting of the resectability of hepatic lesions. Despite T-MRI accurately correlating with intraoperative surgical findings, IOUS should be performed on all patients prior to a final decision to resect or ablate a focal liver lesion.

Adult↗

PubMed2000

Are patients with hyperlipidemia being treated? Investigation of cholesterol treatment practices in an HMO primary care setting.

BACKGROUND: The main study objective was to investigate cholesterol treatment practices of primary care physicians in a managed care setting. METHODS: The study was a retrospective review of data with a quasiexperimental design. The National Cholesterol Education Program-Adult Treatment Panel II (NCEP-ATP II) guidelines were used as the reference for conducting a measurement model in the study. Data were randomly selected via a systematic probability sampling method from a health maintenance organization (HMO) capitated risk-based contracting medical clinic in southern Florida. RESULTS: Of the 348 patients selected for the study, 224 (65%) needed either dietary therapy (n = 106) or drug therapy (n = 118). However, only 16 patients (13.6%) had ever had cholesterol-lowering drug regimens prescribed during the 5-year study period. CONCLUSIONS: Our findings indicate that (1) primary care physicians have poorly adopted the cholesterol management practice recommended by NCEP guidelines and need to improve their recognition and treatment of hypercholesterolemia; and (2) the problem of underutilizing prescription medications may be associated with risk-sharing capitation arrangements between physicians and third-party insurers.

Adult↗

PubMed1998

Assessing data quality for decision support--emphasis on secondary analysis.

In secondary analysis, the use of available data makes it possible for the researcher to bypass the most time-consuming and costly steps in the research process. However, there are some noteworthy pitfalls and problems in working with existing data, especially the uncertainty of data quality. If the integrity and quality of data are not assured, statistical analysis of the data will not be reliable, no matter what statistical procedure is used. If the analysis is not reliable, the information used for decision support will not be accurate.

Data Collection↗

PubMed1997

Study of prevalence, severity, and etiological factors associated with acute pancreatitis in patients infected with human immunodeficiency virus.

OBJECTIVES: Patients with the human immunodeficiency virus (HIV) disease can develop pancreatic gland inflammation from HIV infection and related causes, or from factors totally independent of it. The incidence and severity acute pancreatitis in patients with HIV diseases and the frequency of associated etiological factors have not been examined in any detail. The purpose of this study was to (a) determine the prevalence of acute pancreatitis, (b) evaluate severity of pancreatic gland inflammation, (c) identify commonly associated etiological factors with acute pancreatitis, and (d) examine the relationship between CD4 lymphocyte counts and serum pancreatic enzyme levels (amylase and lipase) in patients with HIV disease. METHODS: We examined the medical records of 321 patients with HIV disease seen at Sinai Hospital of Baltimore between July of 1993 to June of 1994. Data collected from these records included clinical, laboratory, and radiologic features of pancreatitis, staging of HIV disease, risk factors, CD4 lymphocyte counts, medications associated with the presence of opportunistic infections, Kaposi's sarcoma, and lymphoma. RESULTS: From 321 patients with HIV disease, 45 patients developed at least one episode of acute pancreatitis as defined by clinical and laboratory criteria during the 1-yr period. A statistically significant negative correlation was found between serum pancreatic enzyme level and the number of CD4 lymphocytes (r = -0.15, p < 0.05 for serum amylase; r = -0.2, p < 0.05 for serum lipase). Furthermore, patients with asymptomatic HIV infection or CD4 lymphocyte count >500 mm3 did not develop asymptomatic hyperamylasemia or acute pancreatitis. Furthermore, the presence of gallstones, active injection drug use, pentamidine therapy, Pneumocystis carinii, Mycobacterium avium intracellulare correlated significantly (p < 0.001) with the diagnosis of acute pancreatitis. CONCLUSIONS: A detailed review of medical records of patients with HIV disease seen in a community hospital in 1 yr (1993-1994) suggests a high incidence (14%) of mild to moderately severe acute pancreatitis. In this group of patients, pancreatic gland inflammation is commonly associated with gallstones, intravenous drug abuse, pentamidine intake, and Pneumocystis carinii and Mycobacterium avium intracellulare infections. In addition, marked reduction in CD4 lymphocyte count is associated with increase in serum pancreatic enzyme levels (amylase, lipase activity) suggesting pancreatic gland inflammation or altered pancreatic enzyme turnover.

AIDS-Related Opportunistic Infections↗

PubMed1995

[Hereditary gingival fibromatosis: a case report].

Hereditary gingival fibromatosis is an uncommon congenital anomaly of undetermined etiology, the condition is manifested as a dense, diffuse, smooth or nodular overgrowth of the gingival tissue, usually begins with the eruption of the permanent incisors. However, it may happen as early as the eruption of the deciduous teeth. The case, a 30 years old woman with normal stature, visited our dental clinic because of "overgrown gum" which greatly affected mastication and appearance. A review of her past medical history revealed no relevant diseases. Oral examination showed gross fibrous enlargement of gingival without inflammation or swelling. Her father, two sisters and one daughter also suffered from this disease. Microscopically, there is a obvious increase in the amount of connective tissue that is relatively avascular and consists of densely arranged collagen bundles and numerous fibroblasts. The surface epithelium is thickened and acanthotic with elongated rete pegs. Gingivectomy with flap operation were performed to correct the gingival overgrowth. After periodontal treatment, two fixed partial dentures were constructed to replace the missing right upper and lower first molars. One year after operation, no obvious recurrence was noted clinically.

Adult↗

PubMed1994

Novel concepts in modification of radiation sensitivity.

PURPOSE: To determine whether biological effects of radiation, such as apoptosis, that differ from classical clonogenic cell killing, can be modified with agents that would not be expected to modify classical clonogenic cell killing. This would expand the range of potential modifiers of radiation therapy. METHODS AND MATERIALS: EL4 murine lymphoma cell apoptosis was determined by electrophoretic analysis of deoxyribonucleic acid (DNA) fragmentation. DNA was extracted 24 h after irradiation or addition of inducing agents. Modifiers of radiation-induced apoptosis were added immediately after irradiation. The effects of radiation on wounded endothelial monolayers were studied by scraping a line across the monolayer 30 min after irradiation. Cell detachment was used as an endpoint to determine the protective effect of prolonged exposure to retinol prior to irradiation. RESULTS: EL4 cell apoptosis can be induced by tert-butyl hydroperoxide or the glutathione oxidant SR-4077. Radiation-induced EL4 cell apoptosis can be inhibited with 3-aminobenzamide, an agent that sensitizes cells to classical clonogenic cell killing. Radiation-induced endothelial cell detachment from confluent monolayers can be modified by pretreatment with retinol. CONCLUSION: These results raise the possibility that radiation could induce apoptosis by an oxidative stress mechanism that is different from that involved in classical clonogenic cell killing. These and other recent findings encourage the notion that differential modification of classical clonogenic cell killing and other important endpoints of radiation action may be possible.

Animals↗

PubMed1994

Pharmacodynamics of prolonged treatment with L,S-buthionine sulfoximine.

PURPOSE: To develop dosing criteria for the use of L-buthionine-S-sulfoximine (active diastereoisomer) as a glutathione depletor in the clinic, using a pharmacodynamic and pharmacokinetic in vitro-in vivo approach. METHODS AND MATERIALS: In vitro: L-buthionine-S-sulfoximine uptake was determined in human glioblastoma cells (T98G) and NIH-3T3 cells using 35S-labeled drug. Dose response relationships were derived for inhibition of glutathione synthesis in CHO cells, and for depletion of glutathione in exponentially growing T98G and CHO cells, as a function of extracellular L-buthionine-S-sulfoximine concentration. Steady-state glutathione levels for CHO and NIH-3T3 cells were measured using an enzymatic assay, while glutathione synthesis rates in CHO cells were determined using a flow cytometric assay. In vivo: L-buthionine-S-sulfoximine biodistribution was determined in male nude mice carrying human glioblastomas (T98G) intracranially, using 35S-labeled drug infused subcutaneously by osmotic pump. Tissue glutathione levels were measured using an enzymatic assay. RESULTS AND CONCLUSION: The observed cellular uptake t1/2 of approximately 55 min, coupled with a previously reported, rapid in vivo clearance of buthionine sulfoximine, suggest that continuous infusion would be preferable to bolus dosing. Effective concentrations of L-buthionine-S-sulfoximine (24 h exposure), required to lower cellular glutathione content to 50% of control (EC50), were under 1 mM for both cell lines. The amount of L-buthionine-S-sulfoximine in tissues (estimated from 35S drug disposition) reached steady state within 8 h and was proportional to the rate of infusion. Brain tumors were depleted to approximately 50% of control glutathione by a infusion rate of 0.25 mumoles/h (25 g mice). At lower infusion rates an increase in glutathione content was noted in certain nude mouse tissues including brain tumor xenografts.

3T3 Cells↗

PubMed1989

Studies on avian erythrocyte metabolism. XVII. Kinetics and transport properties of myo-inositol in chicken reticulocytes.

The uptake of myo-inositol was determined in a reticulocyte-enriched fraction prepared from chicken blood and compared with uptake in mature erythrocytes. While reticulocytes accumulated inositol at levels more than threefold that of the plasma concentration, erythrocyte levels were only slightly higher than that of the plasma concentration. The rate of uptake in reticulocytes was approximately 66 mumol/ml rbc/h compared to 5 mumol/ml rbc/h in mature erythrocytes when measured at an inositol medium concentration of 250 microM. The kinetic analysis of inositol influx by reticulocytes reveals a two component system: saturable and nonsaturable. The saturable component, which has a Km for inositol of approximately 222 microM, is Na-dependent. This Na-dependent saturable component, which presumably reflects active transport of inositol, accounts for 30-35% of the transport process. The saturable component is completely inhibited by amiloride but to a lesser extent by ouabain and bumetanide. Moreover, in the course of reticulocyte maturation, the saturable component is lost concomitantly with the completion of the synthesis of myo-inositol pentakisphosphate and the drastic decrease in the membrane permeability to inositol. In addition, phloretin and cytochalasin B, which bind to hexose carriers and inhibit hexose sugar transport, also inhibited inositol transport. The uptake of inositol was not affected by excesses of 3-O-methylglucose (100 mM) or by physiological concentrations of D-glucose. Thus, the transport mechanism of myo-inositol appears distinct from that of D-glucose.

Animals↗

PubMed1987

Studies on avian erythrocyte metabolism. XVI. Accumulation of 2,3-bisphosphoglycerate with shifts in oxygen affinity of chicken erythrocytes.

The ability of the chicken erythrocyte to accumulate 2,3-bisphosphoglycerate (2,3-P2-glycerate) and its effect upon the oxygen affinity (P50) of the cell suspensions have been determined. Erythrocytes from chick embryos, which contain 4-6 mM 2,3-P2-glycerate, and from chickens at various ages, which contain 3-4 mM inositol pentakisphosphate but no 2,3-P2-glycerate, were incubated with inosine, pyruvate, and inorganic phosphate. Red blood cells from 20-day chick embryos incubated in Krebs-Ringer, pH 7.45, containing 20 mM inosine and 20 mM pyruvate had an increase in 2,3-P2-glycerate from 4.3 to 11.9 mM after 4 h. Importantly, as 2,3-P2-glycerate concentration increased there was a corresponding increase in P50 of the cell suspension. Further, erythrocytes from 9- and 11-week, and 7-, 14-, 24-, and 28-month-old chickens when incubated similarly with inosine and pyruvate accumulated 2,3-P2-glycerate with corresponding increases in P50 of the cell suspensions. The ability of the red cell to accumulate this compound under the incubation conditions used apparently decreases with age of the bird (e.g., 11.9 mM in the 20-day embryo to 1.1 mM in the 28-month-old chicken after 4 h incubation). Despite the presence of significant amounts of inositol-P5, the accumulation of 2,3-P2-glycerate markedly decreases oxygen affinity of the cell suspensions. The delta P50/mumol increase in 2,3-P2-glycerate in the red cells of the 20-day chick embryo after 4 h incubation is 1.5 Torr; conversely, the delta P50/mumol decrease in 2,3-P2-glycerate in the red cells of the 17-day embryo after 6 h incubation in the presence of sodium bisulfite is 2.8 Torr. The demonstrated ability of the chicken erythrocyte to accumulate 2,3-P2-glycerate in response to certain substrates suggests that regulation of concentration of this compound could contribute significantly to regulation of blood oxygen affinity in birds.

2,3-Diphosphoglycerate↗