4-Hydroxynonenal, an end-product of lipid peroxidation, induces apoptosis in human leukemic T- and B-cell lines

4-Hydroxynonenal (HNE) is the major aldehydic product resulting from lipid peroxidation and has been implicated as involved in several pathological conditions. In our continuing studies on the role of membranes and lipid peroxidation in the induction of apoptosis, we investigated the effect of HNE on cultured human malignant immune system cells. Two cell lines were utilized; MOLT-4, a human T-cell leukemia cell line, and Reh, a human B-cell lymphoma cell line. A 10 min treatment with 0.01 mM HNE resulted in the apoptotic death, as determined by flow cytometric and morphological analyses, of both cell lines within 24 h. MOLT-4 cells exhibited the manifestations of impending apoptotic death much sooner than did Reh cells, indicating that MOLT-4 cells were more sensitive or not as efficient at detoxifying HNE than were Reh cells. These results suggest that peroxidative damage to cellular membranes resulting in the production of HNE may be a trigger for the induction of apoptosis in immune system cells.

Effect of systemic lupus erythematosus (SLE) treatment drugs on GI-101A breast tumor cell growth

The effect of systemic lupus erythematosus (SLE) treatment drugs on PKC (protein kinase C) activity and cell growth was studied using GI-101A breast tumor cells. Both hydroxychloroquine (HCQ) and prednisone treatments significantly increased the PKC activity in GI-101A cells after 60 min. Treatment of cells with a combination of HCQ/prednisone also produced the highest increase in PKC activity following 60 min incubation. When the GI-101A cells were treated with the same drugs, HCQ (10 ng/ml) prednisone (10 ng/ml) and HCQ/prednisone combination (10 ng/ml of each), for 72 hr the total PKC activity in the cells was significantly elevated and consequently the GI-101A cell growth was stimulated. As a result of drug induced cell growth stimulation the total number of cells in the treatment groups increased significantly compared to the non-treated controls. Interestingly HCQ and prednisone treatment induced cell growths were completely blocked by PKC specific inhibitor chelerythrine (50 microM). Our results suggest that HCQ and prednisone treatment can induce GI-101A cell growth via activating PKC.

Delayed catabolism of apoB-48 lipoproteins due to decreased heparan sulfate proteoglycan production in diabetic mice

We used wild-type (WT) mice and mice engineered to express either apoB-100 only (B100 mice) or apoB-48 only (B48 mice) to examine the effects of streptozotocin-induced diabetes (DM) on apoB-100- and apoB-48-containing lipoproteins. Plasma lipids increased with DM in WT mice, and fat tolerance was markedly impaired. Lipoprotein profiles showed increased levels and cholesterol enrichment of VLDL in diabetic B48 mice but not in B100 mice. C apolipoproteins, in particular apoC-I in VLDL, were increased. To investigate the basis of the increase in apoB-48 lipoproteins in streptozotocin-treated animals, we characterized several parameters of lipoprotein metabolism. Triglyceride and apoB production rates were normal, as were plasma lipase activity, VLDL glycosaminoglycan binding, and VLDL lipolysis. However, beta-VLDL clearance decreased due to decreased trapping by the liver. Whereas LRP activity was normal, livers from treated mice incorporated significantly less sulfate into heparan sulfate proteoglycans (HSPG) than did controls. Hepatoma (HepG2) cells and endothelial cells cultured in high glucose also showed decreased sulfate and glucosamine incorporation into HSPG. Western blots of livers from diabetic mice showed a decrease in the HSPG core protein, perlecan. Delayed clearance of postprandial apoB-48-containing lipoproteins in DM appears to be due to decreased hepatic perlecan HSPG.

Expression of vascular endothelial growth factor mRNA in GI-101A and HL-60 cell lines

Vascular endothelial growth factor (VEGF) is a potent angiogenic factor that has a strong association with growth and metastasis of various cancers. We analyzed the expression of VEGF mRNA levels in human breast-tumor derived GI-101A cells and in human promyelocytic leukemia derived HL-60 cells using RT-PCR technique. During our RT-PCR analysis we detected the expression of three splice variants of VEGF mRNA at 400, 520 and, 650 bp lengths, which were amplified by a single set of VEGF specific forward and reverse primers. The three RT-PCR products detected by us in these cells correspond to the mRNA splice variants coding for the three isoforms of VEGF respectively, VEGF(121), VEGF(165), and VEGF(189). Treatment of GI-101A and HL-60 cells with phorbol 12, 13-dibutyrate (PDB) or diethylstilbestrol (DES) resulted in a significant increase of VEGF mRNA levels in a dose dependent manner. Both treatments increased the levels of all three splice variants of VEGF mRNA and a maximum increase was detected with 10 microM concentrations of PDB or DES treatments after 2 h. Interestingly, both PDB and DES mediated stimulation of VEGF mRNA expression was completely blocked by the PKC inhibitor chelerythrine. Quantitation of VEGF levels by ELISA technique confirmed that changes seen in mRNA levels following different treatments altered the release of VEGF. Our results suggest that PDB and DES mediated effects on VEGF expression in GI-101A and HL-60 cells occur at the gene transcription level.

Feeding inhibition and mortality in Reticulitermes flavipes (Isoptera: Rhinotermitidae) after exposure to imidacloprid-treated soils

Feeding inhibition and mortality of Reticulitermes flavipes (Kollar) exposed to sand, sandy loam, loam, and silty clay loam soils treated with several concentrations of imidacloprid were studied using bioassay techniques under laboratory conditions. Termite workers stopped feeding after exposure to treated soils. Differences in feeding reduction varied among the soil types. Based on the magnitude of the F-statistics, the effect of imidacloprid on the reduction of termite feeding was greatest in sand followed by sandy loam, loam, and silty clay loam soils. Soil properties such as organic matter content, silt and clay proportions, pH, and cation exchange capacity were suggested to affect the bioavailability of imidacloprid. Similar soil effects on mortality were observed in termites continuously exposed to treated soil for 21 d. In three of four soils tested, susceptibility to imidacloprid was not affected by the source of the termites tested.

Kearns Sayre syndrome: an atypical presentation

Kearns Sayre syndrome is a rare presentation which usually involves a triad of factors: external ophthalmoplegia, retinal pigmentary degeneration, and heart block. We present a clinically and histopathologically confirmed case of Kearns Sayre syndrome that involved no retinal pathology.

Streptozotocin-induced diabetes in human apolipoprotein B transgenic mice. Effects on lipoproteins and atherosclerosis

The effects of diabetes and lipoprotein lipase (LpL) on plasma lipids were studied in mice expressing human apolipoprotein B (HuBTg). Our overall objective was to produce a diabetic mouse model in which the sole effects of blood glucose elevation on atherosclerosis could be assessed. Mice were made diabetic by intraperitoneal injection of streptozotocin, which led to a 2- to 2. 5-fold increase in plasma glucose. Lipids were assessed in mice on chow and on an atherogenic Western type diet (WTD), consisting of 21% (wt/wt) fat and 0.15% (wt/wt) cholesterol. Plasma triglyceride and cholesterol were the same in diabetic and non-diabetic mice on the chow diet. On the WTD, male diabetic HuBTg mice had a >50% increase in plasma cholesterol and more very low density lipoprotein (VLDL) cholesterol and triglyceride as assessed by FPLC analysis. A Triton study showed no increase in triglyceride or apolipoprotein B production, suggesting that the accumulation of VLDL was due to a decrease in lipoprotein clearance. Surprisingly, the VLDL increase in these mice was not due to a decrease in LpL activity in postheparin plasma. To test whether LpL overexpression would alter these diabetes-induced lipoprotein changes, HuBTg mice were crossed with mice expressing human LpL in muscle. LpL overexpression reduced plasma triglyceride, but not cholesterol, in male mice on WTD. Aortic root atherosclerosis assessed in 32-week-old mice on the WTD was not greater in diabetic mice. In summary, diabetes primarily increased plasma VLDL in HuBTg mice. LpL activity was not decreased in these animals. However, additional LpL expression eliminated the diabetic lipoprotein changes. These mice did not have more atherosclerosis with diabetes.

HDL-subpopulation patterns in response to reductions in dietary total and saturated fat intakes in healthy subjects

BACKGROUND

Little information is available about HDL subpopulations during dietary changes.

OBJECTIVE

The objective was to investigate the effect of reductions in total and saturated fat intakes on HDL subpopulations.

DESIGN

Multiracial, young and elderly men and women (n = 103) participating in the double-blind, randomized DELTA (Dietary Effects on Lipoproteins and Thrombogenic Activities) Study consumed 3 different diets, each for 8 wk: an average American diet (AAD: 34.3% total fat,15.0% saturated fat), the American Heart Association Step I diet (28.6% total fat, 9.0% saturated fat), and a diet low in saturated fat (25.3% total fat, 6.1% saturated fat).

RESULTS

HDL(2)-cholesterol concentrations, by differential precipitation, decreased (P < 0.001) in a stepwise fashion after the reduction of total and saturated fat: 0.58 +/- 0.21, 0.53 +/- 0.19, and 0.48 +/- 0.18 mmol/L with the AAD, Step I, and low-fat diets, respectively. HDL(3) cholesterol decreased (P < 0.01) less: 0.76 +/- 0.13, 0.73 +/- 0.12, and 0.72 +/- 0.11 mmol/L with the AAD, Step I, and low-fat diets, respectively. As measured by nondenaturing gradient gel electrophoresis, the larger-size HDL(2b) subpopulation decreased with the reduction in dietary fat, and a corresponding relative increase was seen for the smaller-sized HDL(3a, 3b), and (3c) subpopulations (P < 0.01). HDL(2)-cholesterol concentrations correlated negatively with serum triacylglycerol concentrations on all 3 diets: r = -0.46, -0.37, and -0.45 with the AAD, Step I, and low-fat diets, respectively (P < 0.0001). A similar negative correlation was seen for HDL(2b), whereas HDL(3a, 3b), and (3c) correlated positively with triacylglycerol concentrations. Diet-induced changes in serum triacylglycerol were negatively correlated with changes in HDL(2) and HDL(2b) cholesterol.

CONCLUSIONS

A reduction in dietary total and saturated fat decreased both large (HDL(2) and HDL(2b)) and small, dense HDL subpopulations, although decreases in HDL(2) and HDL(2b) were most pronounced.

Hepatic scavenger receptor BI promotes rapid clearance of high density lipoprotein free cholesterol and its transport into bile

The clearance of free cholesterol from plasma lipoproteins by tissues is of major quantitative importance, but it is not known whether this is passive or receptor-mediated. Based on our finding that scavenger receptor BI (SR-BI) promotes free cholesterol (FC) exchange between high density lipoprotein (HDL) and cells, we tested whether SR-BI would effect FC movement in vivo using [(14)C]FC- and [(3)H]cholesteryl ester (CE)-labeled HDL in mice with increased (SR-BI transgenic (Tg)) or decreased (SR-BI attenuated (att)) hepatic SR-BI expression. The initial clearance of HDL FC was increased in SR-BI Tg mice by 72% and decreased in SR-BI att mice by 53%, but was unchanged in apoA-I knockout mice compared with wild-type mice. Transfer of FC to non-HDL and esterification of FC were minor and could not explain differences. The hepatic uptake of FC was increased in SR-BI Tg mice by 34% and decreased in SR-BI att mice by 22%. CE clearance and uptake gave similar results, but with much slower rates. The uptake of HDL FC and CE by SR-BI Tg primary hepatocytes was increased by 2.2- and 2.6-fold (1-h incubation), respectively, compared with control hepatocytes. In SR-BI Tg mice, the initial biliary secretion of [(14)C]FC was markedly increased, whereas increased [(3)H]FC appeared after a slight delay. Thus, in the mouse, a major portion of the clearance of HDL FC from plasma is mediated by SR-BI.

An immunologically active arabinogalactan from Tinospora cordifolia

An arabinogalactan of mean M(r) 2.2 x 10(6) has been isolated from the dried stems of Tinospora cordifolia and examined by methylation analysis, partial hydrolysis and carboxyl reduction. Purified polysaccharide showed polyclonal mitogenic activity against B-cells, their proliferation did not require macrophages.

Basic pharmacodynamic models for agents that alter production of natural cells

Basic indirect pharmacodynamic models for agents which alter the generation of natural cells based on a life-span concept are introduced. It is assumed that cells (R) are produced at a constant rate (kin), survive for a specific duration TR, and then are lost. The rate of cell loss must equal the production rate but is delayed by TR. A therapeutic agent can stimulate or inhibit the production rate according to the Hill function: 1 +/- H(C(t)) where H(C(t)) contains capacity (Smax) and sensitivity (SC50) constants and C(t) is a pharmacokinetic function. Thus an operative model is [equation: see text] with the baseline condition R0 = kin.TR. One- and two-compartment catenary cell models were examined by simulation to describe the role of pharmacokinetics and cell properties. The area under the effect curve (AUCE) was derived. The models were applied to literature data to describe the stimulatory effects of single doses of hematopoietic growth factors such as granulocyte colony-stimulating factor (G-CSF) on neutrophils, thrombopoietin (TPO) on platelets, and erythropoietin (EPO) on reticulocytes in blood. The models described experimental data adequately and provided cell life-spans and SC50 values. The proposed cell production/loss models can be readily used to analyze the pharmacodynamics of agents which alter cell production yielding realistic physiological parameters.

Influence of recall period on estimates of diarrhoea morbidity in infants in rural Tamilnadu

Data collected on 689 infants, in a study to assess the incidence of diarrhoea and acute respiratory infections during infancy, is used here to quantify the extent of under-reporting in diarrhoea morbidity surveys. The study area consisted of two contiguous primary health centres in Villupuram health unit district in Tamil Nadu, South India. Each day of infancy was assigned a recal period and proportion of diarrhoeal days for various recall period computed. The proportion of diarrhoea was 11.3%, 12.0% and 11.2% for zero, one and two days of recall period, respectively, after which the proportion decreased. The under-reporting of diarrhoea was approximately 15%, 26% and 45% with three, six and 7-13 days of recall period, respectively. As there is considerable under-reporting of diarrhoea morbidity when recall period exceeds three days, it would be best to collect information on diarrhoea at least twice a week in diarrhoeal morbidity surveys.

Blood clearance and tissue uptake of intravenous lipid emulsions containing long-chain and medium-chain triglycerides and fish oil in a mouse model

BACKGROUND

Increasing interest in using different triglycerides (TGs) for specific clinical applications raised the question as to how the emulsion TG composition would affect blood clearance and emulsion delivery to hepatic and extrahepatic tissues.

METHODS

Emulsions used were long-chain soy oil TG (long-chain triglyceride [LCT]), LCT/ medium-chain triglyceride (MCT; 1:1, wt/wt), LCT/MCT/C/omega-3 (5:4:1, wt/wt) and pure fish oil (omega-3 TG) labeled with non-degradable 3H-cholesteryl oleoyl ether (3H-CE) as a particle marker. Mice (C57BL/6J) were injected with four different commercial emulsions at a nonsaturating dose of 0.4 mg TG/20 to 25 g per mouse to obtain 1st order kinetics. Blood was sampled at 0.5, 2, 5, 10, 15, and 25 minutes, and the fractional catabolic rate was determined by fitting a straight line to the logarithm of the blood 3H-CE radioactivity. Retention of 3H-CE for each tissue at 25 minutes reflected organ uptake of the emulsion.

RESULTS

Blood clearance of pure omega-3 TG (10.40% +/- 0.54% pools/h; mean +/- SE) was significantly slower than that of LCT, LCT/MCT, and LCT/MCT/omega-3 emulsion (18.9 +/- 0.6 pools/h, 17.0 +/- 0.96 pools/h, 16.5 +/- 1.08 pools/h, respectively) (p < .01). Based on 3H-CE uptake, LCT, LCT/MCT, and omega-3 TG emulsions showed similar delivery to liver (39% +/- 3.9%, 46% +/- 3.6%, 34% +/- 3.2%). Liver uptake of LCT/MCT/omega-3, (23% +/- 2.2%) was less than LCT/MCT (46% +/-3.6%, p < .0001) and LCT (39% +/- 3.9%, p = .002).

CONCLUSIONS

Results indicate slow blood clearance of pure omega-3 TG emulsion from the blood compared with emulsion in which omega-3 TG was mixed with LCT and MCT. Earlier data showed that omega-3 TG are poorly hydrolyzed in extracellular media and therefore are delivered to tissues as part of the core of emulsion remnants. Thus, our data suggest that the incorporation of omega-3 TG with LCT/MCT will result in greater delivery of omega-3 fatty acids to extrahepatic tissue, which could be important in modulating immune and other responses.

Magnitude of recall bias in the estimation of immunization coverage and its determinants

OBJECTIVE

To study the magnitude of recall bias in the estimation of immunization coverage and to identify its determinants.

DESIGN

A follow-up study of cohort of children for one year; followed by a cross-sectional recall survey.

SUBJECTS

All live births in two contiguous PHC areas in Villupuram district, Tamil Nadu.

METHODS

The prospective data collected from mothers of 774 children was considered as 'Gold Standard' and the retrospective recall data from them was compared with it. This was carried out for individual immunization schedules, namely, DPT, OPV, BCG and measles and for the combined immunization status. Measures such as sensitivity, specificity, positive and negative predictive values were computed. Logistic Regression technique was employed for evaluating the determinants of agreement.

RESULTS

Less than 50% of mothers has immunization cards with them and more than 70% of the cards did not have complete information. The sensitivity of the recall method was 41.3% and the specificity was 79.5% when the complete immunization status was considered. For individual immunization schedules, the sensitivity ranged from 95% for BCG to 53% for measles vaccination and the specificity ranged from 30% for BCG to 68% for measles vaccination. Mother's age emerged out as a significant determinant in the agreement of two methods. Maintenance of immunization cards were very poor.

CONCLUSIONS

Method of obtaining immunization status through recall survey is not sensitive. Proper maintenance of immunization cards and ensuring the availability of them with mothers for inspection are recommended for obtaining accurate estimation of vaccine coverages.

Probucol enhances selective uptake of HDL-associated cholesteryl esters in vitro by a scavenger receptor B-I-dependent mechanism

Recently, the class B, type I scavenger receptor (SR-BI) has been shown to mediate the selective uptake of high density lipoprotein (HDL) cholesteryl esters (CEs), ie, lipid uptake independent of HDL holoparticle uptake. In vivo, this selective uptake delivers CEs to the liver for excretion and to steroidogenic tissues for hormone synthesis. Probucol, a hydrophobic antioxidant drug, lowers plasma cholesterol in humans and rodents and may inhibit progression of atherosclerosis and postangioplasty restenosis. In this study, the effect of probucol on HDL selective CE uptake was investigated in mice and in cells expressing SR-BI. Probucol feeding lowered plasma HDL cholesterol and markedly increased selective CE uptake from HDL in the liver and adrenal glands. However, probucol did not alter SR-BI protein levels in membranes from these organs. When incubated with control Chinese hamster ovary (CHO) cells, HDL isolated from probucol-treated mice (P-HDL) and HDL from control mice (C-HDL) showed similar low selective uptake of CEs. However, when incubated with SR-BI-transfected CHO cells, P-HDL showed a 2-fold increase in selective uptake compared with C-HDL. In an adrenal cell line (Y1-BS1), which expresses SR-BI in an adrenocorticotropic hormone-inducible manner, P-HDL showed significantly greater selective CE uptake than did C-HDL, and the differential response was amplified by adrenocorticotropic hormone treatment. In contrast to P-HDL, incorporation of this compound into HDL in vitro did not result in stimulation of selective CE uptake by SR-BI-transfected CHO cells, even though a significant mass of probucol could be detected in the HDL preparation. The specific interaction of P-HDL with SR-BI in cell culture could be observed after only 24 hours of probucol feeding, when there were minimal changes in HDL size and composition. Thus, probucol or one of its metabolites increases selective CE uptake in vivo by modifying HDL in a way that causes enhanced interaction with SR-BI. The increased interaction of P-HDL with SR-BI in the liver and arterial wall may be partly responsible for the effects of probucol on atherosclerosis and restenosis.

A common Hpa I RFLP of apolipoprotein C-I increases gene transcription and exhibits an ethnically distinct pattern of linkage disequilibrium with the alleles of apolipoprotein E

Apolipoprotein (apo) C-I is a constituent of triglyceride-rich lipoproteins (TGRL) that interferes with their hepatic clearance. Functional polymorphism in the apoC-I gene has not been established. We determined that an Hpa I site variably present at -317 relative to the apoC-I gene is produced by a 4-bp CGTT insertion. The apoC-I Hpa I alleles showed an ethnically distinct pattern of linkage disequilibrium with the alleles of the adjacent apoE gene. The frequency of apoC-I Hpa I-positive (H2) with apoE varepsilon2 was 0. 98, without significant ethnic difference. In contrast, the frequency of H2 with apoE epsilon4 was 0.85 in European-Americans but only 0.55 in African-Americans (P < 0.001). The frequency of H2 with apoE epsilon3 was 0.02 in European-Americans and 0.08 in African-Americans (P < 0.001). African-American apoE epsilon3/epsilon3 carriers of apoC-I H2 had 19% lower fasting triglyceride levels than H1 homozygotes (P = 0.03) along with 18% higher HDL-cholesterol levels (P = 0.02). ApoB levels were 21% lower (P = 0.002). H2-allelic reporter-gene constructions showed 50% higher expression in transient transfection studies. We localized the source of this difference in expression to the CGTT insertion itself. Deletion studies of the H1 allele showed a negative transcriptional effect of the polymorphic region. An H1 oligodeoxynucleotide showed specific binding of a hepatoma-cell nuclear protein not evident with an H2 oligodeoxynucleotide. The H2 sequence may decrease the binding of a negatively acting transcription factor, leading to overexpression of apoC-I. This may produce a functional effect on lipoprotein levels but confirmation is needed in other populations.

Deletion of multiple immediate-early genes from herpes simplex virus reduces cytotoxicity and permits long-term gene expression in neurons

Herpes simplex virus type 1 (HSV-1) has many attractive features that suggest its utility for gene transfer to neurons. However, viral cytotoxicity and transient transgene expression limit practical applications even in the absence of viral replication. Mutant viruses deleted for the immediate early (IE) gene, ICP4, an essential transcriptional transactivator, are toxic to many cell types in culture in which only the remaining IE genes are expressed. In order to test directly the toxicity of other IE gene products in neurons and develop a mutant background capable of longterm transgene expression, we generated mutants deleted for multiple IE genes in various combinations and tested their relative cytotoxicity in 9L rat gliosarcoma cells, Vero monkey kidney cells, and primary rat cortical and dorsal root neurons in culture. Viral mutants deleted simultaneously for the IE genes encoding ICP4, ICP22 and ICP27 showed substantially reduced cytotoxicity compared with viruses deleted for ICP4 alone or ICP4 in combination with either ICP22, ICP27 or ICP47. Infection of neurons in culture with these triple IE deletion mutants substantially enhanced cell survival and permitted transgene expression for over 21 days. Such mutants may prove useful for efficient gene transfer and extended transgene expression in neurons in vitro and in vivo.

Vitamin E dose-response studies in humans with use of deuterated RRR-alpha-tocopherol

BACKGROUND

Supplemental vitamin E does not raise plasma alpha-tocopherol concentrations more than approximately 3-fold.

OBJECTIVE

To elucidate the mechanism for the limitation in plasma alpha-tocopherol, we undertook human supplementation trials using incrementally increased doses of deuterated vitamin E.

DESIGN

Plasma was obtained from 6 healthy, young adults (4 men and 2 women) during 3 sequential supplementation trials with doses of 15, 75, and 150 mg RRR-alpha-tocopheryl acetate labeled with deuterium (d3-RRR-alpha-tocopheryl acetate). A defined diet was provided on the day of deuterated vitamin E administration, but otherwise subjects ate ad libitum.

RESULTS

The areas under the curves calculated from the plasma d3-RRR-alpha-tocopherol concentrations increased linearly with dose--a 10-fold increase in dose resulted in a 10-fold increase in area under the curve. d3-RRR-alpha-Tocopherol absorption and incorporation into plasma did not decrease with increasing dose. At 11 h, the 15-, 75-, and 150-mg doses resulted in 8+/-4%, 21+/-10%, and 37+/-20% labeling, respectively, of plasma vitamin E. Plasma total (labeled plus unlabeled) alpha-tocopherol concentrations before supplementation were 12+/-3 micromol/L and over the 96 h after the dose averaged 13.3+/-2.6, 15.4+/-3.0, and 16.7+/-4.9 micromol/L for the 15-, 75-, and 150-mg doses, respectively.

CONCLUSIONS

d3-RRR-alpha-Tocopherol was incorporated into the plasma in preference to circulating plasma RRR-alpha-tocopherol. This could occur if the newly absorbed d3-RRR-alpha-tocopherol was preferentially used to replenish circulating vitamin E.

LPL promoter -93T/G transition influences fasting and postprandial plasma triglycerides response in African-Americans and Hispanics

The lipoprotein lipase (LPL) promoter -93T/G transition has previously been reported as having a triglyceride (Tg)-lowering effect, whereas the D9N variant has been shown to have a Tg-raising effect. These two variants were studied in 66 healthy subjects of Hispanic and 42 subjects of African-American origin, who had participated in a study of postprandial lipemia. While the allele frequency of the -93G was significantly different in the Hispanics and African Americans (0.09: 95% CI 0.04-0.13 and 0.28: 95% CI 0.19-0.38; P=0.0001, respectively), the N9 allele frequency was not different (0.06: 95% CI 0.02-0.1 and 0.05: 95% CI 0.002-0.093, respectively). Linkage disequilibrium between the -93T/G and D9N was highly significant in Hispanics (delta=0.67. P=0.0001), compared to delta=0.09 (NS) in African-Americans. In the combined group, compared to individuals with the common genotype (TT/DD; n=71) with fasting plasma Tg of 1.34 (+/-4.5% SEM) mmol/l, carriers of the G/D haplotype (TG/DD + GG/DD; n=25) had significantly lower plasma Tg levels of 1.08 (+/-10% SEM) mmol/l (P < 0.02). After the fat meal, compared to individuals with neither mutation, TT/DD, the effect of the G/D haplotype was to reduce significantly postprandial Tg (P < 0.036). Retinyl palmitate concentration at 5 hrs was significantly lower in G/D carriers than TT/DD individuals (P < 0.05). The lipid-raising effect of the N9 allele in carriers of the -93G (TG/DN + GG/DN) and effect on postprandial Tg clearance was not significant in this group. Thus carriers of the G/D haplotype have lower fasting plasma Tg and reduced alimentary lipemia. This allele may be associated with reduced risk of coronary artery disease.

Acetylation at Lys-92 enhances signaling by the chemotaxis response regulator protein CheY

When Escherichia coli cells lacking all chemotaxis proteins except the response regulator CheY are exposed to acetate, clockwise flagellar rotation results, indicating the acetate stimulus has activated signaling by CheY. Acetate can be converted to acetyl-CoA by either of two different metabolic pathways, which proceed through acetyl phosphate or acetyl-AMP intermediates. In turn, CheY can be covalently modified by either intermediate in vitro, leading to phosphorylation or acetylation, respectively. Either pathway is sufficient to support the CheY-mediated response to acetate in vivo. Whereas phosphorylation of Asp-57 is a recognized mechanism for activation of CheY to stimulate clockwise flagellar rotation, acetylation of CheY is less well characterized. We found evidence for multiple CheY acetylation sites by mass spectrometry and directly identified Lys-92 and Lys-109 as acetylation sites by Edman degradation of peptides from [14C]acetate-labeled CheY. Replacement of CheY Lys-92, the preferred acetylation site, with Arg has little effect on chemotaxis but completely prevents the response to acetate via the acetyl-AMP pathway. Thus acetylation of Lys-92 activates clockwise signaling by CheY in vivo. The mechanism by which acetylation activates CheY apparently is not simple charge neutralization, nor does it involve enhanced binding to the FliM flagellar switch protein. Thus acetylation probably affects signal generation by CheY at a step after switch binding.

Three-fold effect of lovastatin treatment on low density lipoprotein metabolism in subjects with hyperlipidemia: increase in receptor activity, decrease in apoB production, and decrease in particle affinity for the receptor. Results from a novel triple-tracer approach

To differentiate effects of lovastatin on low density lipoprotein (LDL) receptor activity from effects on LDL metabolic properties, LDL apolipoprotein B (apoB) turnover was studied in eight hyperlipidemic subjects during baseline and lovastatin treatment, in the latter case with LDL tracers isolated during both baseline (CLDL) and drug treatment (Rx-LDL) conditions. Lovastatin (40 mg/day) significantly lowered total plasma and LDL cholesterol levels (27% and 25%, respectively) as well as plasma triglyceride levels (30%). Using contemporaneous tracers (C-LDL before and Rx-LDL during treatment), lovastatin caused a modest increase in LDL fractional catabolic rate (FCR) (0.410+/-0.113 vs. 0.339+/-0.108 pools/day, P < 0.04 by paired t). The increase in LDL tracer FCR was higher when C-LDL tracer isolated during the untreated period was injected during lovastatin treatment (0.496+/-0.177 vs. 0.339+/-0.108 pools/day, P < 0.02). These in vivo studies in humans were confirmed by injecting LDL tracers from two patients into five guinea pigs. The C-LDL tracer was cleared consistently faster than the Rx-LDL tracer (0.082+/-0.018 vs. 0.057+/-0.015 pools/h, P< 0.001). The results demonstrate three important outcomes of lovastatin treatment in these subjects: LDL receptor activity increased by 49% (P < 0.02); LDL apoB production rate decreased by 17% (P < 0.03), and LDL particle in vivo affinity for the LDL receptor decreased by 15% (P < 0.01). The decrease in LDL particle affinity partially negated the expected effect of increased LDL receptors on LDL clearance. The present study provides an explanation for earlier observations by several investigators using contemporaneous tracers that treatment with HMG-CoA reductase inhibitors resulted in only modest increases in low density lipoprotein functional catabolic rate.

The role of artificial drainage devices in glaucoma surgery

The use of artificial drainage devices (ADDs) or "setons" in glaucoma surgery is generally restricted to patients with refractory glaucoma at high risk for failure from conventional filtration surgery. ADDs, both valved and nonvalved are currently available in this country. Recently, some of these devices have been propogated as primary treatment even for primary glaucomas. This article examines the role of ADDs in the modern management of the glaucomas. Specific indications for ADDs and methods to reduce the complication of overfiltration are discussed. The use of antimitotics, such as 5-fluorouracil or mitomycin, with traditional filtration has decreased the indications for ADDs. The literature and our experience confirm that currently there is no role for use of ADDs as a primary procedure in most glaucomas.

Effects of reducing dietary saturated fatty acids on plasma lipids and lipoproteins in healthy subjects: the DELTA Study, protocol 1

Few well-controlled diet studies have investigated the effects of reducing dietary saturated fatty acid (SFA) intake in premenopausal and postmenopausal women or in blacks. We conducted a multicenter, randomized, crossover-design trial of the effects of reducing dietary SFA on plasma lipids and lipoproteins in 103 healthy adults 22 to 67 years old. There were 46 men and 57 women, of whom 26 were black, 18 were postmenopausal women, and 16 were men > or =40 years old. All meals and snacks, except Saturday dinner, were prepared and served by the research centers. The study was designed to compare three diets: an average American diet (AAD), a Step 1 diet, and a low-SFA (Low-Sat) diet. Dietary cholesterol was constant. Diet composition was validated and monitored by a central laboratory. Each diet was consumed for 8 weeks, and blood samples were obtained during weeks 5 through 8. The compositions of the three diets were as follows: AAD, 34.3% kcal fat and 15.0% kcal SFA; Step 1, 28.6% kcal fat and 9.0% kcal SFA; and Low-Sat, 25.3% kcal fat and 6.1% kcal SFA. Each diet provided approximately 275 mg cholesterol/d. Compared with AAD, plasma total cholesterol in the whole group fell 5% on Step 1 and 9% on Low-Sat. LDL cholesterol was 7% lower on Step 1 and 11% lower on Low-Sat than on the AAD (both P<.01). Similar responses were seen in each subgroup. HDL cholesterol fell 7% on Step 1 and 11% on Low-Sat (both P<.01). Reductions in HDL cholesterol were seen in all subgroups except blacks and older men. Plasma triglyceride levels increased approximately 9% between AAD and Step 1 but did not increase further from Step 1 to Low-Sat. Changes in triglyceride levels were not significant in most subgroups. Surprisingly, plasma Lp(a) concentrations increased in a stepwise fashion as SFA was reduced. In a well-controlled feeding study, stepwise reductions in SFA resulted in parallel reductions in plasma total and LDL cholesterol levels. Diet effects were remarkably similar in several subgroups of men and women and in blacks. The reductions in total and LDL cholesterol achieved in these different subgroups indicate that diet can have a significant impact on risk for atherosclerotic cardiovascular disease in the total population.