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Y Lam

Publications and source records attributed to Y Lam.

At least 19 recordsLinked to original sources
PubMed2003

On the sensitivity of wall stresses in diseased arteries to variable material properties.

Accurate estimates of stress in an atherosclerotic lesion require knowledge of the material properties of its components (e.g., normal wall, fibrous plaque, calcified regions, lipid pools) that can only be approximated. This leads to considerable uncertainty in these computational predictions. A study was conducted to test the sensitivity of predicted levels of stress and strain to the parameter values of plaque used in finite element analysis. Results show that the stresses within the arterial wall, fibrous plaque, calcified plaque, and lipid pool have low sensitivities for variation in the elastic modulus. Even a +/- 50% variation in elastic modulus leads to less than a 10% change in stress at the site of rupture. Sensitivity to variations in elastic modulus is comparable between isotropic nonlinear, isotropic nonlinear with residual strains, and transversely isotropic linear models. Therefore, stress analysis may be used with confidence that uncertainty in the material properties generates relatively small errors in the prediction of wall stresses. Either isotropic nonlinear or anisotropic linear models provide useful estimates, however the predictions in regions of stress concentration (e.g., the site of rupture) are somewhat more sensitive to the specific model used, increasing by up to 30% from the isotropic nonlinear to orthotropic model in the present example. Changes resulting from the introduction of residual stresses are much smaller.

Anisotropy↗
PubMed2002

Anti-U-like: a common antibody in Black individuals.

BACKGROUND AND OBJECTIVES: Anti-Uz, a scarce antibody, defines a glycophorin B high-incidence antigen, which is protease-sensitive. In a few years, we have encountered 12 antibodies of similar specificity, made by Black individuals of the S- s+ U+ phenotype. MATERIALS AND METHODS: Antibodies were characterized by serological methods, with common and rare MNS types, as well as red cells treated with various proteases. RESULTS: Anti-U-like, mostly an autoantibody, was of IgG class and reacted optimally by indirect antiglobulin test at 20 degrees C. The corresponding antigen was destroyed by several proteases. Tests with papain-treated or Dantu+ cells suggested the existence of several subspecificities. CONCLUSION: Anti-U-like is common in the African population, though its reactions are often misinterpreted. The fact that antibody producers are always Black patients remains unexplained. No relationship with a pathological state could be established.

Agglutination Tests↗
PubMed2001

High-yield, in vitro protein expression using a continuous-exchange, coupled transcription/ translation system.

The Rapid Translation System (RTS 500) (Roche Molecular Biochemicals) is a high-yield protein expression system that utilizes an enhanced E. coli lysate for an in vitro transcription/translation reaction. In contrast to conventional transcription/translation, this system allows protein expression to continue for more than 24 h. We demonstrated the utility of the RTS 500 by expressing different soluble and active proteins that generally pose problems in cell-based expression systems. We first expressed GFP-lunasin, a fusion protein that, because of its toxicity, has been impossible to produce in whole cells. The second protein we expressed, human interleukin-2 (IL-2), is generally difficult to produce, either as the native molecule or as a GSTfusion protein, in a soluble form in bacteria. Finally, we demonstrated the capacity of the RTS 500 to co-express proteins, by the simultaneous production of GFP and CAT in a single reaction. This new technology appears to be particularly usefulfor the convenient production of preparative amounts (100-900 microg) of proteins that are toxic or insoluble in cell-based systems.

3T3 Cells↗
PubMed2001

After Chanukah.

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Aged↗
PubMed1999

Human metabolism of mammalian lignan precursors in raw and processed flaxseed.

BACKGROUND: The mammalian lignans enterolactone and enterodiol are produced in the colon by the action of bacteria on the plant precursor secoisolariciresinol diglycoside, which is found in high concentrations in flaxseed. OBJECTIVE: Two experiments were conducted to determine 1) whether there is a dose response in urinary lignan excretion with increasing flaxseed intake, 2) whether flaxseed processing affects lignan excretion, 3) peak plasma lignan concentrations, and 4) plasma lignan concentrations after chronic supplementation. DESIGN: Nine healthy young women supplemented their diets with 5, 15, or 25 g raw or 25 g processed (muffin or bread) flaxseed for 7 d during the follicular phase of their menstrual cycles. Twenty-four-hour urine samples were collected at baseline and on the final day of supplementation. As an adjunct to the 25-g-flaxseed arm, subjects consumed the supplement for an additional day and blood and urine samples were collected at specific intervals. All blood and urine samples were analyzed for enterolactone and enterodiol by gas chromatography-mass spectroscopy. RESULTS: A dose-dependent urinary lignan response to raw flaxseed was observed (r = 0.72, P < 0.001). The processing of flaxseed as a muffin or bread did not affect the quantity of lignan excretion. Plasma lignan concentrations were greater (P < or = 0.05) than baseline by 9 h after flaxseed ingestion (29.35+/-3.69 and 51.75+/-7.49 nmol/L, respectively). The total plasma area under the curve was higher on the eighth than on the first day (1840.15+/-343.02 and 1027.15+/-95.71 nmol x h/L, respectively). CONCLUSION: Mammalian lignan production from flaxseed precursors is dependent on time and dose but not on processing.

4-Butyrolactone↗
PubMed1999

Etomidate and the osteocalcin response to gynaecological surgery.

Circulating osteocalcin is a good marker of osteoblastic activity and decreases significantly after stressful physiological states such as major surgery. Glucocorticoids are known to inhibit osteoblastic activity and result in a decline in circulating osteocalcin. We used etomidate to inhibit the cortisol response to routine gynaecological surgery to determine if this would prevent the postoperative decline in osteocalcin. Twenty-four patients were allocated randomly to receive either thiopental or etomidate for induction of anaesthesia; all other aspects of anaesthesia and perioperative management were standardized. In the thiopental group, circulating cortisol increased significantly at 2 and 6 h after the start of surgery and plasma osteocalcin concentrations decreased significantly to almost 50% of baseline values at 48 h. Etomidate abolished the cortisol response to surgery, and circulating osteocalcin concentrations did not change after operation. There was a significant difference in osteocalcin concentration between the groups at 48 h. We conclude that the cortisol response to surgery is associated with a postoperative decrease in circulating osteocalcin.

Adult↗
PubMed1996

Home visit.

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Diabetes Mellitus↗
PubMed1995

Starch, gloves and extradural catheters.

We have investigated contamination of extradural catheters during normal handling with starch powdered gloves. In the laboratory, extradural catheters were handled in sterile fields with both powdered and non-powdered gloves, simulating preparation for patient insertion. The catheters together with glove samples were then examined using a Zeiss 940 scanning electron microscope. Microscopy of samples revealed starch contamination of the catheters handled with powdered gloves, especially in the side hole areas. We conclude that extradural catheters may be contaminated easily by starch powder from surgical gloves. This powder may then be deposited into the extradural space. The effect of starch in the extradural space is not known but starch is known to cause inflammatory and granulomatous reactions in other parts of the body as well as being directly allergenic. Powder contamination of catheters may be avoided easily by the use of powder-free gloves and we feel that these should be used whenever possible.

Analgesia, Epidural↗
PubMed1992

Purification and characterization of a novel enoyl coenzyme A reductase from Streptomyces collinus.

A novel NADPH-dependent enoyl reductase, catalyzing the conversion of 1-cyclohexenylcarbonyl coenzyme A (1-cyclohexenylcarbonyl-CoA) to cyclohexylcarbonyl-CoA, was purified to homogeneity from Streptomyces collinus. This enzyme, a dimer with subunits of identical M(r) (36,000), exhibits a Km of 1.5 +/- 0.3 microM for NADPH and 25 +/- 3 microM for 1-cyclohexenylcarbonyl-CoA. It has a pH optimum of 7.5, is most active at 30 degrees C, and is inhibited by both divalent cations and thiol reagents. Two internal peptide sequences were obtained. Ansatrienin A (an antibiotic produced by S. collinus) contains a cyclohexanecarboxylic acid moiety, and it is suggested that the 1-cyclohexenylcarbonyl-CoA reductase described herein catalyzes the final reductive step in the conversion of shikimic acid into this moiety.

Amino Acid Sequence↗
PubMed1991

Phase I-II study of two consecutive courses of high-dose epipodophyllotoxin, ifosfamide, and carboplatin with autologous bone marrow transplantation for treatment of adult patients with solid tumors.

We describe a phase I-II study of two consecutive 5-day courses of a three-drug regimen of ifosfamide (IFM), carboplatin (CBDCA), and either etoposide (VP-16) (regimen 1) or teniposide (VM-26) (regimen 2) in high doses together with autologous bone marrow transplantation (ABMT), for previously treated patients with ovarian carcinoma (OC), germ cell tumors (GCT), gestational trophoblastic disease (GTD), or oat cell carcinoma (OCC). Forty-four patients entered the study. Two patients with OC received regimen 1, and 22 were given regimen 2. Sixteen patients with GCT, two with GTD, and two with OCC were treated with regimen 1. Six patients (13%) died of toxicity. Nephropathy and esophagitis were the dose-limiting toxic effects. The maximum-tolerated doses (MTDs) were 1,500 and 200 mg/m2/d for 5 days for IFM and CBDCA, respectively, in combination with VP-16 250 mg/m2/d for 5 days (regimen 1), and 150, 1,500, and 200 mg/m2/d for 5 days for VM-26, IFM, and CBDCA, respectively (regimen 2). The response rate of patients with OC was 78% (complete response [CR], 14%). For patients previously resistant to chemotherapy, the response rate was 70%. There were no long-term disease-free survivors among patients with OC. The response rate of patients with GCT was 60% (CR, 33%). All responders with GCT were resistant to previous chemotherapy. Unmaintained CRs lasted 2, 6, 8+, 27+, and 37+ months. Of the two patients with GTD, one with previous resistance to chemotherapy attained a CR of 18+ months. One patient with OCC attained a CR lasting 6 months. The regimen possesses great antitumor activity. It produced CRs of long duration in a number of patients with GCT and GTD who were previously resistant to chemotherapy.

Adult↗
PubMed1989

Hypocholesterolemic effect of vegetable protein in a hypocaloric diet.

Eleven obese volunteers took part in a 12-week study during 8 weeks of which 2 meals of their control 1000 kcal diets were replaced by a soya based liquid formula (1 month) or a milk based liquid formula (1 month). The mean weight loss per month was 2.5 kg (P less than 0.05). On the soya formula total and LDL cholesterol levels were reduced significantly over the month by 10.0 +/- 2.7% (P less than 0.01) and 17.5 +/- 5.6% (P less than 0.02), respectively. Neither the milk based formula or the control low calorie diet lowered serum cholesterol significantly over the diet period. No change was seen in serum triglycerides on any of the 3 diets. No difference was seen between treatments in 24-h urinary C-peptide excretion. The results indicated that use of a vegetable protein supplement in a weight loss program which induced moderate weight loss was associated with a reduction in blood lipids, whereas moderate weight loss on a control low calorie diet or milk based formula was not.

Adult↗
PubMed1988

Prevention of HLA immunization with leukocyte-poor packed red cells and platelet concentrates obtained by filtration.

HLA immunization is a common complication of transfusion therapy in 30% to 60% of oncohematologic patients. Evidence shows that leukocytes present in cellular blood products are the main component involved in the occurrence of HLA immunization, and several studies showed that leukocyte-poor blood products are less able to induce it. However, leukocyte-poor platelet concentrates obtained by conventional techniques, ie, centrifugation, frequently have a high level of remaining leukocytes. Cotton wool filter Imugard IG 500 can be used to obtain leukocyte-poor cellular blood products. The technique is easy to perform, even in an emergency, and can be used with either packed RBCs or platelet concentrates. Means of 97%, 92%, and 76% elimination of leukocytes are obtained for packed RBCs, pooled standard platelet concentrates, and single-donor platelet concentrates, respectively. Patients were randomized to receive either standard (control group) or filtered (leukocyte-poor group) blood products. Of 112 randomized patients, 69 were evaluable, 35 in the control group and 34 in the leukocyte-poor group. Both groups are comparable according to age, diagnosis, sex ratio, previous transfusions, and pregnancies. There is a significant difference in regard to the HLA immunization rate (31.4% in the control v 11.7% in the leukocyte-poor group, P less than .05) and frequency of refractoriness to platelet transfusions (46.6% v 11.7%, P less than .05). We conclude that this filtration technique can be an efficient means to reduce the HLA immunization rate in polytransfused oncohematologic patients.

Adolescent↗
PubMed1987

Metabolic effects of a low-glycemic-index diet.

Six healthy male volunteers underwent 2-wk metabolically controlled high-glycemic-index (GI) and low-GI diets in random order. Over the low-GI diet significant reductions were seen in serum fructosamine (7.0 +/- 1.0%, p less than 0.01), 12-h blood glucose profile (37 +/- 7%, p less than 0.01), and total serum cholesterol (15 +/- 3%, p less than 0.01). As a measure of insulin secretion, 24-h urinary C-peptide levels were 32 +/- 10% lower (p less than 0.05) after the low-GI than after the high-GI diet. Lower C-peptide levels were maintained after a standard carbohydrate challenge after the low-GI diet despite higher blood glucose levels. Differences in blood glucose were not seen after a 5-g intravenous glucose challenge. These results are of interest with respect to the effect that prolonged postprandial reductions in nutrient fluxes and insulin secretion may have on carbohydrate and lipid metabolism and renal function.

Adult↗