Should treatment recommendations for lipid lowering drugs be based on absolute coronary risk or risk reduction?
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Aged↗
Biomedical subjects
S Ramachandran
Publications and source records attributed to S Ramachandran.
Multiple factors other than p53 influence colon cancer sensitivity to paclitaxel.
PURPOSE: To determine factors which influence the sensitivity of human colorectal carcinoma cell lines to paclitaxel. METHODS: The paclitaxel sensitivity of ten human colorectal carcinoma cell lines, and a panel of RKO colon carcinoma cell lines, isogenic except for p53 status, were studied. The inhibitory concentrations causing a 50% decrease in growth (IC50) were assayed after 3, 24, and 96 h after paclitaxel exposure. The doubling time (DT) and cell cycle parameters of cells were also measured. The expression of the multidrug resistance glycoprotein-1 (MDR-1), bcl-2 and bax was quantitatively assessed by immunoblotting. RESULTS: Mean IC50 values at 24 and 96 h drug exposure were about 1.5 logs lower than the IC50 values at 3 h, regardless of the p53 status. No difference was found between the IC50 values of wild-type and mutant p53 cells, or among the RKO panel of cells. Correlation analysis showed that: (1) resistance was associated with longer DTs, but this was generally abated by a 96-h exposure; (2) with a 3-h exposure, the combination of MDR, bcl-2 and bax parameters with DT (DT + MDR + bcl-2 bax) best correlated with IC50 values (r = 0.77); (3) with a 96-h exposure, in spite of the generally decreased IC50 values, a combination of MDR-1, bcl-2 and bax parameters (MDR + bcl-2-bax) best correlated with the IC50 values (r = 0.71). CONCLUSIONS: These results suggest that the exposure duration, DT, and expression of MDR-1, bcl-2 and bax each contribute to paclitaxel sensitivity of human colorectal carcinoma cells. In assessing paclitaxel drug resistance, multiple factors should always be considered. There may be a therapeutic window for taxanes in colon cancer by optimizing pharmacokinetics and modulating MDR-1 and bcl-2 resistance factors.
Antineoplastic Agents, Phytogenic↗
Implications in the maintenance of pregnancy: I. Presence of immunoreactive glycodelin in human umbilical cord vein endothelial cells.
OBJECTIVE: We previously reported an antipeptide antibody to human glycodelin that recognizes glycodelin in amniotic fluid and epithelial glands of the endometrium. The objective of this study was to determine the presence of glycodelin in human umbilical cord. DESIGN: Controlled clinical study. SETTING: Healthy women undergoing normal delivery at Grady Memorial Hospital, Atlanta, Georgia. PATIENT(S): Healthy women undergoing normal delivery. INTERVENTION(S): None. MAIN OUTCOME MEASURE(S): Umbilical cord vein was isolated from the cord and used for immunohistochemical studies. Human umbilical cords and placentae were collected after full-term delivery. Cords were washed and fixed with formal sucrose. Decidua tissues and blood vessels from placentae were dissected out and fixed. Cryostat sections were immunostained with anti-glycodelin peptide antibody and anti-von Willebrand factor antibody. RESULT(S): Endothelial cells of human umbilical cord vein and artery were strongly immunostained with antiglycodelin antibody. Endothelial cells of the vein were more strongly stained than those of the artery. These cells were confirmed as endothelial cells by positive immunostaining with anti-von Willebrand factor. The epithelial cells outlining the cord were stained with antiglycodelin antibody but not with anti-von Willebrand factor antibody. CONCLUSION(S): This is the first study showing that immunoreactive glycodelin is present in endothelial cells of the umbilical cord. Glycodelin in the umbilical cord may have immunosuppressive or other, unknown functions affecting the physiology or pathophysiology of pregnancy. Whether umbilical vein endothelial cells synthesize glycodelin or serve as reservoir for glycodelin is currently under investigation.
Case-Control Studies↗
Implications in the management of pregnancy: II. Low levels of gene expression but enhanced uptake and accumulation of umbilical cord glycodelin.
OBJECTIVE: We recently reported the presence of glycodelin in the endothelial cells of human umbilical cord. The objective of the current study is to determine whether human umbilical cord endothelial cells synthesize glycodelin. DESIGN: Controlled clinical study. SETTING: Healthy women undergoing normal delivery at Grady Memorial Hospital, Atlanta, Georgia. PATIENT(S): Healthy women undergoing normal delivery. INTERVENTION(S): None. MAIN OUTCOME MEASURE(S): Human umbilical cord was collected after full-term delivery and total RNA from endothelial cells was isolated. Reverse-transcription polymerase chain reaction (RT-PCR) was performed by using primers from glycodelin sequence. Human umbilical cord endothelial cells at passage 3 were incubated with glycodelin-derived peptide or glycodelin-rich amniotic fluid. Immunocytochemical analysis was performed by using purified chicken anti-glycodelin peptide antibody to detect the accumulation of glycodelin in cells. RESULT(S): Little or no glycodelin message was detectable in the endothelial cells from human umbilical cord vein by RT-PCR and Southern blot analysis. However, these cells readily took up glycodelin protein and glycodelin-derived synthetic peptide from the medium. CONCLUSION(S): The presence and accumulation of glycodelin in the umbilical cord might indicate their potential role in the survival of fetal tissue in the maternal environment.
Blotting, Western↗
Identification of parasitic genes by computational methods.
A number of parasite genome projects are under way, and large amounts of nucleotide sequence data are becoming available for analysis. There is an urgent need for development of theoretical tools to analyze the genome data, including identification of protein-coding sequences. The majority of the methods developed to date require prior information about the genome before accurate predictions can be made. Because such information is not available for many parasites, these methods cannot be directly applied. In this article, Alok Bhattacharya and colleagues describe some of the gene-prediction methods commonly in use, and a new method, GeneScan, that they have developed for the analysis of parasite genomes.
Animals↗
Potential role of oxidized lipids and lipoproteins in antioxidant defense.
The atherogenic oxidative modification of low-density lipoprotein is suggested to occur in the aortic intima. There is reasonable evidence to suggest that antioxidants might be beneficial in preventing or retarding the progression of atherosclerosis. Exercise, estrogens, and substitution of polyunsaturated fat for saturated fat are beneficial in the prevention of atherosclerosis. Yet, paradoxically, they are capable of inducing an oxidative stress. To reconcile with this paradox, we postulate that under certain conditions an oxidative stress might be beneficial by inducing antioxidant enzymes in arterial cells. However, those with genetic deficiency in antioxidant enzymes or those who poorly respond to oxidative stress or those with overwhelming plasma oxidative stress might need additional antioxidant protection.
Animals↗
Chemosensory proteins from the proboscis of mamestra brassicae.
Soluble, low molecular weight proteins were immunodetected in proboscis extracts of Mamestra brassicae males by Western blot, using antibodies raised against the general odorant-binding protein of the moth Antheraea polyphemus. The same antibodies weakly labelled the sensillum lymph and subcuticular space of sensilla styloconica on ultrathin sections of the proboscis. The morphology of sensilla styloconica is described. The immunodetected proteins yielded several N-terminal sequences, three of which showed strong affinity for tritiated analogues of pheromonal compounds of M. brassicae in binding assays. The cDNAs coding for these sequences were cloned and it was shown that the new proteins are related to the OS-D protein of Drosophila. They are named chemosensory proteins (CSP-MBRA:A1-CSP-MBRA:A5 and CSP-MBRA:B1 and CSP-MBRA:B2) and may have an odorant-binding protein-like function. A common localization in both olfaction and taste organs suggests a physiological role depending on the cellular environment.
Amino Acid Sequence↗
Glutathione S-transferase GSTP1 and cyclin D1 genotypes: association with numbers of basal cell carcinomas in a patient subgroup at high-risk of multiple tumours.
We previously described associations between basal cell carcinoma (BCC) numbers and allelic variants at loci that mediate host response to ultraviolet radiation (UV). These associations were largely exerted in cases with the multiple presentation phenotype (MPP). This phenotype describes patients who present at their first or a later presentation with a cluster of BCC (2-10 new BCC). Remaining BCC cases have the single presentation phenotype (SPP) and may develop more than one BCC but only have single new lesions at any presentation. We proposed that the MPP cases comprise a high-risk group as they suffer significantly more lesions than SPP cases. We are attempting to determine, in the total BCC case group and subgroups, how many genes influence BCC numbers and their relative importance. In this study, we assessed the influence of two further candidates, glutathione S-transferase GSTP1 and cyclin D1 (CCND1), on tumour numbers in a total group of 457 patients comprising MPP and SPP cases. The relative importance of these genes in comparison with occupational UV exposure and host response (skin type) was also considered. We found that the frequencies of GSTP1 genotypes based on the Ile105 and Val105-expressing alleles and CCND1 AA, AG, GG genotypes were similar in MPP and SPP cases and that there were no significant associations between GSTP1 or CCND1 genotypes and BCC numbers in the total or SPP groups. However, in the MPP cases, GSTP1 Val105/Val105 was associated with more tumours (P = 0.05, reference GSTP1 Ile105/Ile105). Inclusion of skin type and indoor/outdoor occupation in the negative binomial regression models did not alter the associations of these genotypes with tumour numbers. DNA from 258 cases was analysed to identify GSTP1*A (Ile105-Ala114), GSTP1*B (Val105-Ala114), GSTP1*C (Val105-Val114) and GSTP1*D (Ile105-Val114). In SPP cases, there was no association between BCC numbers and GSTP1 BB, though the association with GSTP1 BC approached significance (P = 0.09). In MPP cases, GSTP1 BC was associated with BCC numbers (P = 0.03). We also found that the interaction term, GSTP1 Val105/Val105 with CCND1 AA, was associated with BCC numbers in the total (P = 0.001) and MPP (P = 0.006) but not SPP (P = 0.68) groups. In a stepwise model including GSTP1 Val105/Val105, CCND1 AA and their interaction terms as well as GSTM1, GSTT1 and CYP2D6 genotypes, skin type 1 and gender, the combination of genotypes was the best predictor of BCC numbers. These data suggest that study of further genes involved in cell-cycle control and protection from oxidative stress will be useful, particularly in high-risk subgroups.
Basal Cell Carcinoma↗
Profilin plays a role in cell elongation, cell shape maintenance, and flowering in Arabidopsis.
Profilin (PFN) is an ubiquitous, low-M(r), actin-binding protein involved in the organization of the cytoskeleton of eukaryotes including higher plants. PFNs are encoded by a multigene family in Arabidopsis. We have analyzed in vivo functions of Arabidopsis PFN by generating transgenic plants carrying a 35S-PFN-1 or 35S-antisense PFN-1 transgene. Etiolated seedlings underexpressing PFN (PFN-U) displayed an overall dwarf phenotype with short hypocotyls whose lengths were 20% to 25% that of wild type (WT) at low temperatures. Light-grown PFN-U plants were smaller in stature and flowered early. Compared with equivalent cells in WT, most cells in PFN-U hypocotyls and roots were shorter, but more isodiametric, and microscopic observations of etiolated PFN-U hypocotyls revealed a rough epidermal surface. In contrast, light-grown seedlings overexpressing PFN had longer roots and root hair although etiolated seedlings overexpressing PFN were either the same size or slightly longer than WT seedlings. Transgenic seedlings harboring a PFN-1-GUS transgene directed expression in root and root hair and in a ring of cells at the elongating zone of the root tip. As the seedlings matured PFN-1-GUS was mainly expressed in the vascular bundles of cotyledons and leaves. Our results show that Arabidopsis PFNs play a role in cell elongation, cell shape maintenance, polarized growth of root hair, and unexpectedly, in determination of flowering time.
Actins↗
Hyperlipidaemia and primary prevention of coronary heart disease: are the right patients being treated?
BACKGROUND: In 1997, the Standing Medical Advisory Committee report suggested that patients with a coronary heart disease risk of 3% per year or greater should be considered appropriate for lipid-lowering medication. The report stated that cholesterol concentration alone is a poor predictor of absolute risk of coronary heart disease and recommended the Sheffield table as a method of estimating the coronary heart disease risk. OBJECTIVE: To assess the impact of the Standing Medical Advisory Committee report on the management of patients with hyperlipidaemia in the primary prevention of coronary heart disease in primary care. METHOD: A survey questionnaire giving the clinical details of 20 patients with various coronary heart disease risk factors was sent to 200 general practitioners in the West Midlands, UK. RESULTS: Forty-eight percent of the respondents used clinical assessment/perception as the sole means of risk assessment and 26% used the Sheffield table. In patients who did not require treatment, 40.1% of the decisions were inappropriate and, in patients who required treatment, 35.1% of the decisions were inappropriate. Overall, inappropriate decisions were made in 37.9% of the responses. Despite the clear advice in the Standing Medical Advisory Committee report on the importance of incorporating multiple risk factors in estimating absolute coronary heart disease risk, only total cholesterol and triglycerides were significant in influencing treatment decisions. CONCLUSIONS: The Standing Medical Advisory Committee recommendations on the management of hyperlipidaemia in primary prevention of coronary heart disease are not widely used. Large savings could be made by correctly identifying and treating individuals at high risk. We recommend use of the full Framingham risk score in assessment of coronary heart disease risk in primary care.
Adult↗
Isolation and analysis of three peroxide sensor regulatory gene homologs ahpC, ahpX and oxyR in Streptomyces viridosporus T7A--a lignocellulose degrading actinomycete.
Increased lignolytic peroxidase activity has been demonstrated with the addition of sublethal doses of toxic H2O2 in Streptomyces viridosporus T7A. Until now, the effect of H2O2 at the molecular level has not been well characterized. Here, for the first time we report the isolation and analysis of three peroxide-induced gene homologs from S. viridosporus T7A; ahpC and ahpX (encoding alkyl hydroxyperoxidase subunits) and oxyR (encoding oxygen stress regulatory protein). The genome organization of these stress related genes were found to be divergently adjacent to each other. The protein sequence analysis of the oxyR homolog revealed a helix-turn-helix DNA-binding motif characteristic to the LysR of regulatory proteins induced by H2O2. The nucleotide sequence analysis of the intergenic region between ahpC and oxyR revealed that they shared a core T-n11-A, a signature protein-binding region of LysR family members. Based on similarities in sequence analysis, genetic organization, and the induction of lignin peroxidase activity upon exposure to hydrogen peroxide, we hypothesize a peroxide induction mechanism for the regulation of oxidative lignin biodegradation by S. viridosporus, possibly via use of OxyR which is also involved in regulating the peroxide stress response in this actinomycete.
Actinomycetales↗
Observed changes in the lipid profile and calculated coronary risk in patients given dietary advice in primary care.
BACKGROUND: Dietary advice is usually the first-line treatment for increased blood cholesterol in primary care with a reduction in levels as the expected response. In practice, the diet adopted by the patient may lead to changes in blood lipids characterised by a greater decrease in high-density lipoprotein (HDL) than total cholesterol. The ratio of total cholesterol to HDL cholesterol is an important factor in calculated coronary risk using the Framingham model, from which most risk tables currently in use have been derived. This suggests that either coronary risk may increase after dietary advice or that risk should always be assessed on measurements made before any intervention has taken place. AIM: To report observed changes in blood lipids and calculated coronary risk following dietary advice in primary care. METHOD: Subjects with at least one coronary risk factor and baseline cholesterol above 5.2 mmol/l from an inner-city general practice had cardiovascular risk factors, including fasting lipids, recorded before receiving dietary advice. At follow-up several months later, risk factor measurements were repeated. Ten-year coronary risk was calculated using the Framingham model. Lipid levels and coronary risk at baseline and follow-up were compared. RESULTS: There was a significant decrease in both total cholesterol and HDL cholesterol in both sexes. However, in 56% of subjects, HDL decreased by a greater proportion than the total cholesterol. These subjects showed a highly significant increase in the total cholesterol/HDL cholesterol ratio (median = 0.8 [semi-interquartile range = 1.5], P < 0.001, which was correlated with a change in triglycerides (rs = 0.309, P < 0.001). In those who had an increase in the total cholesterol/HDL cholesterol ratio, calculated coronary risk increased from 5.45% (13.2) at baseline to 7.25% (15.5) (P < 0.001). In all subjects, the change in calculated coronary risk associated with dietary advice ranged from -15% to 15%. CONCLUSIONS: Low fat dietary advice in this primary care setting was frequently associated with undesirable changes in the lipid profile. The majority of subjects showed an increase in the total cholesterol/HDL cholesterol ratio, owing primarily to a decrease in HDL. Consequently, calculated coronary risk increased in over one-half of the subjects. Owing to our incomplete understanding of HDL metabolism, it is unclear whether the fall in HDL is actually detrimental; however, it seems prudent to give dietary advice to patients to avoid excess simple carbohydrate as a fat substitute. This helps avoid a rise in triglycerides, which appears to be associated with an increase in the ratio. These results confirm that coronary risk should always be calculated using measurements made before intervention.
Adult↗
Rotational dynamics of the regulatory light chain in scallop muscle detected by time-resolved phosphorescence anisotropy.
We have used time-resolved phosphorescence anisotropy (TPA) to study the rotational dynamics of chicken gizzard regulatory light chain (RLC) bound to scallop adductor muscle myofibrils in key physiological states. Native RLC from scallop myofibrils was extracted and replaced completely with gizzard RLC labeled specifically at Cys 108 with erythrosin iodoacetamide (ErIA). The calcium sensitivity of the ATPase activity of the labeled myofibril preparation was quite similar to that of the native sample, indicating that the ErIA-labeled RLC is functionally bound to the myosin head. In rigor (in the absence of ATP, when all the myosin heads are rigidly bound to the thin filament), a slight decay was observed in the first few microseconds, followed by no change in the anisotropy. This indicates small-amplitude restricted motions of the RLC or the entire LC domain of myosin. Addition of calcium to rigor restricts these motions further. Relaxation with ATP (no Ca) causes a large decay in the anisotropy, indicating large-amplitude rotational motion with correlation times of 5-50 micros. Further addition of calcium, to induce contraction, resulted in a decrease in the rate and amplitude of anisotropy decay. In particular, there is clear evidence for a slow rotational motion with a correlation time of approximately 300 micros, which is not present either in rigor or relaxation. This indicates rotational motion that specifically correlates with force generation. The changes in the rotational dynamics of the light-chain domain in rigor, relaxation, and contraction support earlier work based on probes of the catalytic domain that muscle contraction is accompanied by a disorder-to-order transition of the myosin head. However, the motions of the LC domain are different from those of the catalytic domain, which indicates rotation of the two domains relative to each other.
Adenosine Triphosphatases↗
The fusion protein of peste des petits ruminants virus is a hemolysin.
The fusion glycoprotein (F protein) of paramyxoviruses plays a vital role in virus-induced cytopathology. To explore the role of the F protein in peste des petits ruminants virus (PPRV)-induced cytopathology, the F protein of PPRV was purified by immunoaffinity chromatography. The purified F protein, when incubated with chicken erythrocytes, caused lysis suggesting that PPRV F protein is a hemolysin. Furthermore, the hemolysis can be inhibited by hyperimmune serum against F protein. The virus-induced cell fusion (syncytia) was also inhibited by the hyperimmune serum against the F protein. In summary, these results indicate that the purified PPRV F protein is biologically active and is involved in virus-induced hemolysis, cell-fusion and the initiation of infection.
Animals↗
The melanocyte stimulating hormone receptor polymorphism: association of the V92M and A294H alleles with basal cell carcinoma.
Allelic variants in the melanocyte stimulating hormone receptor (MC1R) gene are susceptibility/outcome candidates for cutaneous basal cell carcinoma (BCC). We identified the val92met (V92M) and asp294his (A294H) alleles in 311 cases and 190 controls. The cases included four homo- and 53 heterozygotes for V92M and 12 heterozygotes for A294H and two compound heterozygotes (V92M/A294H). Allele frequencies were similar in controls. In the cases, we found no association between the alleles and skin type though A294H was more common in those with red hair (4/19) than with other hair colours (6/163) (P = 0.012). V92M was not associated with BCC numbers. Cases with A294H had fewer BCC in comparison with those without the allele though the difference was not significant. After inclusion of red hair in the model, A294H was significantly associated with fewer tumours. While MCIR alleles are attractive candidates for BCC, the variants studied did not influence susceptibility. The association with outcome was relatively weak. The large number of MC1R alleles and their low frequency, make assessment of the importance of this gene in the pathogenesis of skin cancers difficult.
Alleles↗
Rheological characterization of hydroxypropylcellulose gels.
The present paper describes the rheological properties of hydroxypropylcellulose (HPC) gels formulated in propylene glycol (PG), water, ethanol, and mixtures of these components. The effects of molecular weight, polymer concentration, and solvent composition on the apparent viscosity and flow characteristics have been studied by continuous shear rheometry. The HPC gels are shear thinning and do not exhibit significant yield or hysteresis in their rheograms. The apparent viscosity increases with increasing molecular weight and concentration of the polymer, as expected. Although not so pronounced at lower concentrations (< or = 1.5%), HPC gels tend to become increasingly non-Newtonian with increasing molecular weight at higher polymer concentrations (3%). A mathematical model has been proposed for the prediction of viscosities of HPC gels. There exists a high degree of dependence on molecular interactions between various solvent molecules in the prediction of mixture viscosities in ternary systems. The effects of solvent composition on the viscoelastic behavior of these gels have also been examined by dynamic mechanical analysis. The HPC gels are highly viscoelastic and exhibit greater degrees of elasticity with increased PG content in ternary solvent mixtures with water and ethanol. The study also suggests that dynamic mechanical analysis could prove to be a useful tool in the determination of zero-shear viscosities, viscosities that are representative of most realistic situations.
Cellulose↗
Association of NAD(P)H:quinone oxidoreductase (NQO1) null with numbers of basal cell carcinomas: use of a multivariate model to rank the relative importance of this polymorphism and those at other relevant loci.
Glutathione S-transferase GSTM1 B and GSTT1 null, and cytochrome P450 CYP2D6 EM have been associated with cutaneous basal cell carcinoma (BCC) numbers, although their quantitative effects show that predisposition to many BCC is determined by an unknown number of further loci. We speculate that other loci that determine response to oxidative stress, such as NAD(H):quinone oxidoreductase (NQO1) are candidates. Accordingly, we assessed the association between NQO1 null and BCC numbers primarily to rank NQO1 null in a model that included genotypes already associated with BCC numbers. We found that only 14 out of 457 cases (3.1%) were NQO1 null. This frequency did not increase in cases with characteristics linked with BCC numbers including gender, skin type, a truncal lesion or more than one new BCC at any presentation (MPP). However, the mean number of BCC in NQO1*0 homozygotes was greater than in wild-type allele homozygotes and heterozygotes, although the difference was not quite significant (P = 0.06). These data reflect the link between NQO1 null and BCC numbers in the 42 MPP cases rather than the whole case group. We identified an interaction between NQO1 null and GSTT1 null that was associated with more BCC (P = 0.04), although only four cases had this combination. The relative influence of NQO1 null was studied in a multivariate model that included: (i) 241 patients in whom GSTM1 B, GSTT1 null and CYP2D6 EM genotype data were available, and (ii) 101 patients in whom these genotypes, as well as data on GSTM3, CYP1A1 and melanocyte-stimulating hormone receptor (MC1R) genotypes were available. NQO1 null (P = 0.001) and MC1R asp294/asp294 (P = 0.03) were linked with BCC numbers, and the association with CYP2D6 EM approached significance (P = 0.08). In a stepwise regression model only these genotypes were significantly associated with BCC numbers with NQO1 null being the most powerful predictor.
Age Factors↗
Modified miniprep method for the rapid recovery of episomes from transfected breast epithelial cells.
Episomal vectors such as pCEP4 are useful in expression cloning because they can replicate in both prokaryotes and eukaryotic cells. We have found a rapid and efficient means of extracting them from transfected MCF-10A nonmalignant human breast epithelial cells. We show that a plasmid miniprep protocol, modified by the addition of an extraction that eliminates a DNase activity, can consistently harvest pCEP4 episomes from the transfected cells (516 +/- 112 pg/harvest, mean +/- standard deviation; n = 11). The quality of the episomal DNA obtained in this manner was verified by PCR, Southern blot and the retransformation of Escherichia coli. This simple method enables the efficient recovery of episomes and is applicable in the expression cloning of potential oncogenes using host MCF-10A cells.
Blotting, Southern↗