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Biomedical subjects

L Tan

Publications and source records attributed to L Tan.

250 records · Page 14Linked to original sources
PubMedDate not supplied

Risk of transmission of bovine spongiform encephalopathy to humans in the United States: report of the Council on Scientific Affairs. American Medical Association.

CONTEXT: The risk of possible transmission of bovine spongiform encephalopathy (BSE) in the United States is a substantial public health concern. OBJECTIVE: To systematically review the current scientific literature and discuss legislation and regulations that have been implemented to prevent the disease. METHODS: Literature review using the MEDLINE, EMBASE, and Lexis/Nexis databases for 1975 through 1997 on the terms bovine spongiform encephalopathy, prion diseases, prions, and Creutzfeldt-Jakob syndrome. The Internet was used to identify regulatory actions and health surveillance. DATA EXTRACTION: MEDLINE, EMBASE, and Lexis/Nexis databases were searched from 1975 through 1997 for English-language articles that provided information on assessment of transmission risk. RESULTS: Unique circumstances in the United Kingdom caused the emergence and propagation of BSE in cattle, including widespread use of meat and bonemeal cattle feed derived from scrapie-infected sheep and the adoption of a new type of processing that did not reduce the amount of infectious prions prior to feeding. Many of these circumstances do not exist in the United States. In the United Kingdom, new variant Creutzfeldt-Jakob disease probably resulted from the ingestion of BSE-contaminated processed beef. The United Kingdom and the European Union now have strong regulations in place to stop the spread of BSE. While BSE has not been observed in the United States, the US government has surveillance and response plans in effect. CONCLUSIONS: Current risk of transmission of BSE in the United States is minimal because (1) BSE has not been shown to exist in this country; (2) adequate regulations exist to prevent entry of foreign sources of BSE into the United States; (3) adequate regulations exist to prevent undetected cases of BSE from uncontrolled amplification within the US cattle population; and (4) adequate preventive guidelines exist to prevent high-risk bovine materials from contaminating products intended for human consumption.

American Medical Association↗
PubMedDate not supplied

HPLC determination of captopril in human plasma and its pharmacokinetic study.

A simple and sensitive reversed-phase liquid chromatographic method has been developed and validated for the analysis of captopril in human plasma and the study of the pharmacokinetics of the drug in human body. Captopril was stabilized by forming an adduct with p-bromophenacyl bromide. The adduct formed and 4-chloro-2-nitroaniline (internal standard) were extracted with ethyl acetate:benzene (1:1), and then measured by HPLC using a Spherisorb C18 column as stationary phase and a water:acetonitrile:acetic acid mixture (44:55:0.2, v/v/v) as mobile phase. Captopril was quantified by absorbance at 258 nm. The method proved to be linear in the clinical range of 5-500 ng/mL. The lower limit of detection of captopril in plasma was 2 ng/mL. Intra-day and inter-day coefficients of variation of assay for captopril in plasma were 5.8%-8.5% (n = 7) and 8.0%-9.5% (n = 5), respectively. The recoveries of captopril were 90%-98% for plasma. The data obtained was fitted with 3P87 program on computer to study the pharmacokinetics. The results showed that the disposition of captopril was conformed to a two-compartment open model with Tmax = 0.56 h, Cmax = 266.5 ng/mL and AUC(zero)-infinity = 380.3 ng.h/mL. The method has been used to determine captopril in plasma samples from ten volunteers and provided data on the pharmacokinetics of the drug. The results inferred that captopril is absorbed rapidly and had a relatively short half-life time in healthy individuals.

Administration, Oral↗
PubMedDate not supplied

Correlation of immunological surface antigens with survival in diffuse large cell lymphoma.

The prognostic value of immunophenotyping lymphomas with a panel of monoclonal antibodies (Mab) to various lymphoid antigens was assessed by studying 47 cases of diffuse large cell lymphoma. Cell suspensions were analysed by flow cytometry after labelling by indirect immunofluorescence. Thirty-eight cases were demonstrated to be of B cell and nine of T cell phenotype. Univariate analysis demonstrated that survival was significantly longer in patients expressing higher levels of HLA-DR (p = 0.01) and normal levels of CD8 (p = 0.04) but was not significantly associated with any of the other antigens. Our results support the possible value of HLA-DR in determining the prognosis of patients with diffuse large cell lymphoma.

Adult↗
PubMedDate not supplied

The detection of Plasmodium falciparum and P. vivax in DNA-extracted blood samples using polymerase chain reaction.

Seventeen pairs of published primer sets were compared for their relative sensitivity to detect malaria DNA extracted from blood samples, which were obtained from Pakistani patients suffering from malaria. The primer sets investigated consisted of: (i) 9 pairs of direct primers and 3 sets of nested primers for detecting Plasmodium falciparum, (ii) 2 pairs of direct primers and 2 sets of nested primers for detecting P. vivax, and (iii) 1 set of multiplex primers for detecting both P. falciparum and P. vivax, simultaneously. After a miniscreen of 9 DNA-extracted blood samples using the 17 primer sets stated above, 5 primer sets were short-listed (based on their superior sensitivity) and used for a maxi-screen of DNA extracted from 126 microscopy-positive blood samples from Pakistan, with the following results. (i) For the detection of P. falciparum, the direct primer pair 'PF1 + PF2' gave a sensitivity of 95% and the nested primer set 'RIT405 + RIT406/RIT371 + RIT372' gave a sensitivity of 97%. (ii) For the detection of P. vivax, the direct primer pair 'Forward + Reverse' and the nested primer set 'PLF + UNR/PLF + VIR' both gave a sensitivity of 94%. (iii) The nested multiplex primer set 'rPLU5 + rPLU6/rFAL1 + rFAL2 + rVIV1 + rVIV2' gave a sensitivity of 97% and 96% for P. falciparum and P. vivax, respectively. It was concluded that the nested multiplex primer set was the most optimal primer set to use for the detection of malaria DNA extracted from blood samples. Furthermore, the nested multiplex primer set has the advantage of simultaneously detecting and differentiating between P. vivax and P. falciparum.

Animals↗
PubMedDate not supplied

The utilization of midazolam as a pharmacologic adjunct to endotracheal intubation by paramedics.

OBJECTIVE: Pharmacologic agents have been used in the prehospital setting for facilitating endotracheal intubation (ETI). The purpose of this study was to determine the utility of intravenous midazolam for prehospital patients who require pharmacologic relaxation to facilitate ETI. METHODS: Data were reviewed retrospectively using paramedic charts from an eight-month period for a three-county state EMS system. RESULTS: There were 26,133 paramedic dispatches during the study period. Six hundred eighty-three ETIs were attempted, including 72 midazolam-facilitated intubations (MFIs). The most common indications for MFI were "clenched teeth," "gag," and "combativeness." Successful MFI was achieved in 45 of 72 cases (62.5%). Midazolam-facilitated intubation was less successful for trauma patients (41.2%) than for medical patients (69.1 %) (p = 0.04). Of the 58 failed conventional ETIs that occurred during the study period, 25 (43.1%) were identified as having one or more indications for the use of MFI. Although the use of intravenous midazolam was effective in facilitating ETI, a high MFI failure rate (37.5%) was noted. CONCLUSION: Although it is of limited efficacy, MFI is underutilized and should be considered by medical direction as a pharmacologic adjunct to ETI in selected field patients.

Delaware↗
PubMedDate not supplied

Telopeptides as markers of bone turnover in rheumatoid arthritis and osteoarthritis.

AIMS: The aim of the present study was to determine if urinary excretion of type I collagen N-terminal telopeptides (UrNTx) and deoxypyridinoline (UrDPD) and serum levels of type I collagen C-terminal telopeptides (SeCTx) differed in patients with rheumatoid arthritis (RA) compared with populations matched for age and gender with and without osteoarthritis (OA). The correlation of markers of bone turnover with disease activity in patients with RA or radiographic severity in patients with OA was also examined. METHODS: Patients with RA aged >50 years (men) and >60 years (women) were identified from computer databases at two tertiary referral centres for rheumatology. Strict exclusion criteria were applied to avoid the effects of factors known to influence markers of bone turnover. Patients with RA and OA were matched for age and sex with a control population free of known arthritic disease and a population with OA. Bone markers were assayed in serum and urine. Urine markers were measured on three consecutive days and mean values used to minimize day-to-day variability of these analytes. RESULTS: The level of UrNTx was elevated in patients with RA compared with normal controls and patients with OA. UrNTx and UrDPD correlated with markers of disease activity in patients with RA (erythrocyte -sedimentation rate and C-reactive protein), but not with -clinical signs of inflammation (swollen and tender joint counts). Patients with OA failed to show any correlation between markers of bone turnover and radiographic severity. CONCLUSIONS: These data support a role for the use of UrNTx and UrDPD in further studies of the patho-physiology of RA and in longitudinal studies designed to modify the course of clinical disease.

Aged↗
PubMedDate not supplied

Conventional and sprinkler needle injection of magnesium insulin.

Currently available short-acting insulin preparations fail to mimic the postprandial insulin profile of non-diabetic individuals. The activity of a novel insulin designed for faster absorption has been tested after subcutaneous injection. Magnesium insulin (50 U ml-1) given by sprinkler needle was compared with unmodified human insulin (100 U ml-1) given by conventional needle and unmodified human insulin (50 U ml-1) given by sprinkler needle in normal volunteers using a euglycaemic clamp. Magnesium insulin had a significantly faster onset of action resulting in a higher exogenous insulin level by 15 min, peak level was reached after 60 min compared with 75 min for the unmodified insulins, and duration of action was significantly shorter than both unmodified insulins. No significant differences were observed between the unmodified insulins for the first 5 h after injection, indicating that the observed differences to magnesium insulin could not be attributed to the insulin concentration or the type of needle used for insulin administration. Injection of magnesium insulin prior to a test breakfast in people with Type 2 diabetes resulted in significantly lower total and 0 to 120 min areas under the glucose curve, an earlier rise in exogenous insulin levels and a higher area under the insulin curve from 0 to 120 min compared with unmodified 100 U ml-1 human insulin.

Adult↗
PubMedDate not supplied

An evaluation of total parenteral nutrition using Vamin and Aminosyn as protein base in critically ill preterm infants.

A total of 75 preterm infants with gestation less than 32 wk received total parenteral nutrition (TPN) using Vamin and Aminosyn as protein base lasting more than 20 days. They were monitored for signs of liver dysfunction, cholestatic jaundice, and TPN-induced metabolic bone disease (osteopenia of prematurity). It was observed that severity of TPN-induced cholestasis depends on the duration of TPN and quantity of protein infused. When used as a protein base, Vamin seemed to be superior to Aminosyn. TPN-induced metabolic bone disease was strongly correlated to the duration of TPN. We suggest close monitoring of critically ill preterm infants on TPN for quantity of protein infusate, liver dysfunction, cholestatic jaundice, and TPN-induced metabolic bone disease. Intravenous protein intake should be limited to less than 2.5 g/kg/day in preterm infants with gestation less than 32 wk.

Amino Acids↗
PubMedDate not supplied

Liposarcoma of the spermatic cord.

A case of spermatic cord liposarcoma is reported in a 40-year-old man. The clinical presentation, pathogenesis and role of sonography in pre-operative diagnosis is reviewed. The role of radical orchiectomy, retroperitoneal lymph node dissection, radiation therapy and chemotherapy in treatment of spermatic cord liposarcomas is discussed.

Adult↗
PubMedDate not supplied

From "thrifty genotype" to "hefty fetal phenotype": the relationship between high birthweight and diabetes in Saskatchewan Registered Indians.

BACKGROUND: Intrauterine factors have been implicated in the pathogenesis of Type 2 diabetes mellitus (T2DM). METHODS: In a 1:1 matched pairs case-control study, high and low birthweight (HBW, LBW) rates in Saskatchewan Registered Indian (RI) diabetic cases were compared with corresponding rates in RI without diabetes, and non-RI people with and without diabetes. RESULTS: Birthweights were available for 73% of the 1,366 cases and 3 x 1,366 controls. A greater proportion of RI diabetics were born with HBW (> 4000 grams) compared to RI non-diabetics (16.2% vs 10.7%; p < 0.01). There was a significant association between HBW (but not LBW [< 2500 grams]) and diabetes for RI people (OR 1.63 [95% CI 1.20, 2.24]), which was stronger for RI females and strengthened progressively from mid to late 20th century. INTERPRETATION: Certain causes of HBW may predispose to subsequent development of T2DM in Canadian Aboriginal people ("hefty fetal phenotype" ["hefty fetal type"] hypothesis). Programs that optimize healthy pregnancies could reduce T2DM incidence in future generations.

Adolescent↗
PubMedDate not supplied

Identification of the aromatase in the breast carcinoma cell lines T47D and MCF-7.

The presence of estrogens in tumour cells is considered to be a critical factor for the development of the hormone-dependent forms of breast cancer. The last, rate-limiting step of estrogen biosynthesis is controlled by cytochrome P-450 type enzyme complex named aromatase. In the present study we determined and characterized the expression of aromatase mRNA in the breast carcinoma cell lines T47D and MCF-7. The expression was characterized by slot blot hybridization, reverse transcriptase-polymerase chain reaction technique and Northern hybridization analysis. Northern blotting revealed the presence of 4.4 kb and 2.4 kb messengers in both cell lines.

Aromatase↗
PubMedDate not supplied

6-Hydroximinoandrostenedione, a new specific inhibitor of estrogen biosynthesis and its effect on T47D human breast cancer cells.

A new male steroid hormone analogue, 6-hydroximinoandrostenedione, was obtained in 12% yield by an 8-step synthesis. The compound is cytochrome P450 aromatase-specific, inducing a Type-1 optical difference spectrum with the human placental enzyme (Ks 2.24 microM). It efficiently inhibits human cytochrome P450 aromatase (Ki 0.08 microM) in a time--and concentration--dependent manner, but no conclusive evidence was found that it also inactivates the placental enzyme. Cultured human T47D breast cancer cells have the unique capacity to convert de novo [14C]androstenedione into radioactive estrone and estradiol, as we have established by repetitive HPLC purifications of the biosynthetic products formed. A very small amount of an unidentified radioactive metabolite was also formed. We conclude that an endogenous androgen - aromatizing enzyme is present in T47D cells; a fact not previously reported for this human breast cancer cell line. Furthermore, the new aromatase inhibitor was found to cause a significant decrease in the growth of these cells. Our results indicate that: 1) growth of T47D cancer cells is estrogen-dependent, 2) substitution at the C-6 "front" face of an androst-4-ene-3-one molecule does not cause rejection of the modified C19 male steroidhormone by the aromatase enzyme, 3) the new 6-hydroximinoandrostenedione inhibitor has the potential to act as a highly specific anti-aromatase breast cancer agent.

Androstenedione↗
PubMedDate not supplied

The effect of a handicapped child upon a family.

Each family is individual in the way it reacts and adjusts to a handicapped child. How and when staff first break the news is important. It can affect the way the parents are able to cope and adjust. If midwives and other staff handle and speak about the baby in a positive, accepting way, this will help the parents to do so too. Parents often need to grieve for the "normal" child they have lost. The parents' relationship may break down under the physical, social and financial strains. The health visitor or social worker may be able to help. Some families grow closer as a result of a handicapped child, others become dysfunctional. Siblings' needs may be overlooked. Here again, the health visitor or social worker may be able to help.

Adaptation, Psychological↗