Treatment of COVID-19 pneumonia with low-dose radiotherapy plus standard of care versus standard of care alone in frail patients : The SEOR-GICOR IPACOVID comparative cohort trial.

PURPOSE: To assess the efficacy of lung low-dose radiotherapy (LD-RT) in the treatment of patients with COVID-19 pneumonia. MATERIALS AND METHODS: Ambispective study with two cohorts to compare treatment with standard of care (SoC) plus a single dose of 0.5 Gy to the whole thorax (experimental prospective cohort) with SoC alone (control retrospective cohort) for patients with COVID-19 pneumonia not candidates for admission to the intensive care unit (ICU) for mechanical ventilation. RESULTS: Fifty patients treated with LD-RT were compared with 50 matched controls. Mean age was 85 years in both groups. An increase in arterial oxygen partial pressure (PaO2)/fraction of inspired oxygen (PAFI) in the experimental LD-RT-treated group compared to the control group could not be found at 48 h after LD-RT, which was the primary endpoint of the study. However, PAFI values significantly improved after 1 month (473 vs. 302 mm Hg; p < 0.0001). Pulse oxymetric saturation/fraction of inspired oxygen (SAFI) values were also significantly higher in LD-RT-treated patients than in control patients at 1 week (405 vs. 334 mm Hg; p = 0.0157) and 1 month after LD-RT (462 vs. 326 mm Hg; p < 0.0001). All other timepoint measurements of the respiratory parameters were similar across groups. Patients in the experimental group were discharged from the hospital significantly earlier (23 vs. 31 days; p = 0.047). Fifteen and 26 patients died due to COVID-19 pneumonia in the experimental and control cohorts, respectively (30% vs. 48%; p = 0.1). LD-RT was associated with a decreased odds ratio (OR) for 1­month COVID-19 mortality (OR = 0.302 [0.106-0.859]; p = 0.025) when adjusted for potentially confounding factors. Overall survival was significantly prolonged in the LD-RT group compared to the control group (log-rank p = 0.027). No adverse events related to radiation treatment were observed. CONCLUSION: Treatment of frail patients with COVID-19 pneumonia with SoC plus single-dose LD-RT of 0.5 Gy improved respiratory parameters, reduced the period of hospitalization, decreased the rate of 1­month mortality, and prolonged actuarial overall survival compared to SoC alone.

Effects of radiotherapy on plasma energy metabolites in patients with breast cancer who received neoadjuvant chemotherapy.

PURPOSE: Neoadjuvant chemotherapy (NACT) is employed in patients with breast cancer (BC) with the aim of reducing tumor burden and improving surgical outcomes. We evaluated the levels of energy metabolites pre- and post-radiotherapy (RT) in breast cancer (BC) patients who previously received NACT and investigated the alterations of these metabolites in relation to the patient achieving a pathologic complete response to NACT. MATERIALS AND METHODS: We included 37 BC patients who were treated with NACT following surgery and analyzed the concentrations of energy balance-related metabolites using targeted metabolomics before and one month after the end of RT. The control group was composed of 44 healthy women. RESULTS: Pre-radiotherapy, patients had significant decreases in the plasma levels of 12 metabolites. RT corrected these alterations and the improvement was superior in patients with a pathologic complete response. CONCLUSION: Our results highlight the importance of metabolism in the outcomes of patients with BC.

Exploitation of thermal gradients for investigation of irradiation temperature effects with charged particles.

The effects of radiation damage on materials are strongly dependant on temperature, making it arguably the most significant parameter of concern in nuclear engineering. Owing to the challenges and expense of irradiating and testing materials, material property data is often limited to few irradiation conditions and material variants. A new technique has been developed which enables the investigation of radiation damage of samples subject to a thermal gradient, whereby a wealth of data over a range of irradiation temperatures is produced from a single irradiation experiment. The results produced are practically inaccessible by use of multiple conventional isothermal irradiations. We present a precipitation-hardened copper alloy (CuCrZr) case-study irradiated with a linear temperature gradient between 125 and 440 °C. Subsequent micro-scale post irradiation characterisation (nanoindentation, transmission electron microscopy and atom probe tomography) highlight the capability to observe mechanical and microstructural changes over a wide range of irradiation temperatures. We observed irradiation-softening in CuCrZr that did not occur due to irradiation-enhanced aging of the Cr-precipitates. Excellent reproducibility of the new technique was demonstrated and replicated irradiation-hardening data from several isothermal neutron irradiation studies. Our new technique provides this data at a fraction of the time and cost required by conventional irradiation experiments.

Paraoxonase-1 activity in patients with cancer: A systematic review and meta-analysis.

PURPOSE: Paraoxonase-1 (PON1) is a lipolactonase implicated in the elimination of carcinogenic free radicals and in the scavenging mechanisms to maintain oxidative balance. The objective of the present systematic review and meta-analysis was to evaluate possible alterations in serum PON1 activity in patients with cancer. METHODS: A systematic search of the observational studies in humans published in the last 15 years was performed through Medline databases following the PRISMA and STARLITE statements. Further, a keyword-based computerized search with restrictions on publication date, and a meta-analysis of case-control studies was performed. RESULTS: In total, 23 studies were included most of which reported decreased PON1 activity in patients with cancer. This could indicate impaired defense ability against oxidative stress with potential implications in cell proliferation, promotion of genetic instability, and alterations in cellular sensitivity to chemotherapy. CONCLUSION: This systematic review and meta-analysis confirms a consistent association between cancer and decreased serum PON1 activities. These findings may open fruitful lines of research with clinical relevance, and an understanding of molecular alterations underlying carcinogenesis.

Metformin regulates global DNA methylation via mitochondrial one-carbon metabolism.

The anti-diabetic biguanide metformin may exert health-promoting effects via metabolic regulation of the epigenome. Here we show that metformin promotes global DNA methylation in non-cancerous, cancer-prone and metastatic cancer cells by decreasing S-adenosylhomocysteine (SAH), a strong feedback inhibitor of S-adenosylmethionine (SAM)-dependent DNA methyltransferases, while promoting the accumulation of SAM, the universal methyl donor for cellular methylation. Using metformin and a mitochondria/complex I (mCI)-targeted analog of metformin (norMitoMet) in experimental pairs of wild-type and AMP-activated protein kinase (AMPK)-, serine hydroxymethyltransferase 2 (SHMT2)- and mCI-null cells, we provide evidence that metformin increases the SAM:SAH ratio-related methylation capacity by targeting the coupling between serine mitochondrial one-carbon flux and CI activity. By increasing the contribution of one-carbon units to the SAM from folate stores while decreasing SAH in response to AMPK-sensed energetic crisis, metformin can operate as a metabolo-epigenetic regulator capable of reprogramming one of the key conduits linking cellular metabolism to the DNA methylation machinery.

Preliminary study on serum paraoxonase-1 status and chemokine (C-C motif) ligand 2 in hospitalized elderly patients with catheter-associated asymptomatic bacteriuria.

Urinary tract infections (UTI) are common among elderly patients in residential care facilities, as well as in the hospital setting. Identifying new biochemical markers of UTI is an active line of research since UTI management is resource intensive. Paraoxonase-1 (PON1) forms part of the patient's immune system, the response-to-injury and inflammation. Our study sought to evaluate alterations in inflammation-related paraoxonase-1 (PON1) and chemokine (C-C motif) ligand 2 (CCL2) in patients with an indwelling catheter to assess their potential usefulness as biomarkers of infection. Patients (n = 142) who had had the urinary catheter removed and 100 healthy volunteers were recruited. In all participants we measured serum PON1 activity, PON1 concentration, CCL2, procalcitonin and C-reactive protein (CRP). Results indicated that patients had higher CCL2, CRP and procalcitonin concentrations than the control group, and lower paraoxonase activity. There were no significant differences in PON1 concentrations. When comparing the diagnostic accuracy of CRP, procalcitonin, CCL2 and the PON1-related variables in discriminating between patients with and those without UTI, we found a considerable degree of overlap between groups, i.e., a low diagnostic accuracy. However, there were significant inverse logarithmic correlations between serum paraoxonase activity and the number of days the urinary catheter had been in situ. Our results suggest that measurement of these biochemical variables may be useful in investigating complications of long-term use of these devices and help to improve the economic and clinical investment required in the management of the often-associated infection.

Mapping of the circulating metabolome reveals α-ketoglutarate as a predictor of morbid obesity-associated non-alcoholic fatty liver disease.

BACKGROUND: Obesity severely affects human health, and the accompanying non-alcoholic fatty liver disease (NAFLD) is associated with high morbidity and mortality. Rapid and non-invasive methods to detect this condition may substantially improve clinical care. METHODS: We used liquid and gas chromatography-quadruple time-of-flight-mass spectrometry (LC/GC-QTOF-MS) analysis in a non-targeted metabolomics approach on the plasma from morbidly obese patients undergoing bariatric surgery to gain a comprehensive measure of metabolite levels. On the basis of these findings, we developed a method (GC-QTOF-MS) for the accurate quantification of plasma α-ketoglutarate to explore its potential as a novel biomarker for the detection of NAFLD. RESULTS: Plasma biochemical differences were observed between patients with and without NAFLD indicating that the accumulation of lipids in hepatocytes decreased ß-oxidation energy production, reduced liver function and altered glucose metabolism. The results obtained from the plasma analysis suggest pathophysiological insights that link lipid and glucose disturbances with α-ketoglutarate. Plasma α-ketoglutarate levels are significantly increased in obese patients compared with lean controls. Among obese patients, the measurement of this metabolite differentiates between those with or without NAFLD. Data from the liver were consistent with data from plasma. Clinical utility was assessed, and the results revealed that plasma α-ketoglutarate is a fair-to-good biomarker in patients (n=230). Other common laboratory liver tests used in routine application did not favourably compare. CONCLUSION: Plasma α-ketoglutarate is superior to common liver function tests in obese patients as a surrogate biomarker of NAFLD. The measurement of this biomarker may potentiate the search for a therapeutic approach, may decrease the need for liver biopsy and may be useful in the assessment of disease progression.

Multifunctional targets of dietary polyphenols in disease: a case for the chemokine network and energy metabolism.

Chronic, non-acute inflammation is behind conditions that represent most of the disease burden in humans and is clearly linked to immune and metabolic mechanisms. The convergence of pathways involving the immune response, oxidative stress, increased circulating lipids and aberrant insulin signaling results in CCL2-associated macrophage recruitment and altered energy metabolism. The CCL2/CCR2 pathway and the energy sensor AMP-activated protein kinase (AMPK) are attractive therapeutic targets as a part of preventive management of disease. Several effects of polyphenols are useful in this scenario, including a reduction in the activities of cytokines and modulation of cellular metabolism through histone deacetylase inhibitors, AMPK activators, calorie-restriction mimetics or epigenetic regulators. Research is currently underway to develop orally active drugs with these effects, but it is convenient to examine more closely what we are eating. If a lack of relevance in terms of toxicity and substantial effectiveness are confirmed, plant-derived components may provide useful druggable components and dietary supplements. We consider therapeutic actions as a combination of synergistic and/or antagonistic interactions in a multi-target strategy. Hence, improvement in food through enrichment with polyphenols with demonstrated activity may represent a major advance in the design of diets with both industrial and sanitary value.

Metformin: a cheap and well-tolerated drug that provides benefits for viral infections.

OBJECTIVES: Insulin resistance in viral infections is common. We have explored the effectiveness of metformin for alleviating insulin resistance in HIV-infected patients and assessed the relevance of the ataxia-telangiectasia mutated (ATM) rs11212617 variant in the clinical response with the rationale that metformin modulates cellular bioenergetics in an ATM-dependent process. METHODS: HIV-infected patients (n = 385) were compared with controls recruited from the general population (n = 300) with respect to the genotype distribution of the ATM rs11212617 variant and its influence on selected metabolic and inflammatory variables. We also followed up a subset of male patients with HIV and hepatitis C virus (HCV) coinfection (n = 47) who were not receiving antiviral treatment and for whom metformin was prescribed for insulin resistance, which tends to have a higher incidence and severity in coinfected patients. RESULTS: Among the HIV-infected patients, human cytomegalovirus (91.9%) and HCV (62.3%) coinfections were frequent. Selected metabolic and/or inflammatory variables were significantly altered in infected patients. Treatment with metformin in HIV and HCV coinfected patients was well tolerated and significantly increased the sensitivity of peripheral tissues to insulin. The minor allele (C) of the rs11212617 variant was associated with treatment success and may affect the course of insulin resistance in response to metformin (odds ratio 1.21; 95% confidence interval 1.07-1.39; P = 0.005). There were no differences between treated and untreated patients in viral loads or variables measuring immune defence, indicating that toxicity is unlikely. CONCLUSIONS: We provide novel data suggesting that identification of the ATM rs11212617 variant may be important in assessing the glycaemic response to metformin treatment for insulin resistance in HIV-infected patients.

The role of combined assessment of defense against oxidative stress and inflammation in the evaluation of peripheral arterial disease.

Atherosclerosis in symptomatic peripheral arterial disease affects wide portions of numerous arteries in lower extremities. The resulting active inflammation in a considerable amount of arterial tissue facilitates systemic detection via measurement of inflammation-related variables. We reasoned that the combined assessment of defense against oxidative stress, in the form of paraoxonase-1 (PON1), and monocyte migration measured as circulating (C-C motif) ligand 2 (CCL2), may play a role in the evaluation of these patients. Plasma CCL2 and serum PON1-related variables, assessed by their interaction with functional genetic variants, were measured in a cross-sectional study in patients with symptomatic PAD. We found that PON1 activity and concentration were significantly lower and CCL2 concentration higher in PAD patients compared to controls, that the combination of plasma CCL2 and PON1- related values, especially PON1 concentration differentiated, almost perfectly, controls from patients and that the expression of CCL2 and PON1 generally co-localized in the atherosclerotic lesion. Since no association with genetic variants was found, such a relationship is probably the result of the disease. Our data suggest a coordinated role between CCL2 and PON1 that may be detected in blood with simple measurements and may represent an indicator of the extent of atherosclerosis.

Continuous administration of polyphenols from aqueous rooibos (Aspalathus linearis) extract ameliorates dietary-induced metabolic disturbances in hyperlipidemic mice.

The incidence of obesity and related metabolic diseases is increasing globally. Current medical treatments often fail to halt the progress of such disturbances, and plant-derived polyphenols are increasingly being investigated as a possible way to provide safe and effective complementary therapy. Rooibos (Aspalathus linearis) is a rich source of polyphenols without caloric and/or stimulant components. We have tentatively characterized 25 phenolic compounds in rooibos extract and studied the effects of continuous aqueous rooibos extract consumption in mice. The effects of this extract, which contained 25% w/w of total polyphenol content, were negligible in animals with no metabolic disturbance but were significant in hyperlipemic mice, especially in those in which energy intake was increased via a Western-type diet that increased the risk of developing metabolic complications. In these mice, we found hypolipemiant activity when given rooibos extract, with significant reductions in serum cholesterol, triglyceride and free fatty acid concentrations. Additionally, we found changes in adipocyte size and number as well as complete prevention of dietary-induced hepatic steatosis. These effects were not related to changes in insulin resistance. Among other possible mechanisms, we present data indicating that the activation of AMP-activated protein kinase (AMPK) and the resulting regulation of cellular energy homeostasis may play a significant role in these effects of rooibos extract. Our findings suggest that adding polyphenols to the daily diet is likely to help in the overall management of metabolic diseases.

Nonconcordance between subclinical atherosclerosis and the calculated Framingham risk score in HIV-infected patients: relationships with serum markers of oxidation and inflammation.

OBJECTIVES: HIV-infected patients show an increased cardiovascular disease (CVD) risk resulting, essentially, from metabolic disturbances related to chronic infection and antiretroviral treatments. The aims of this study were: (1) to evaluate the agreement between the CVD risk estimated using the Framingham risk score (FRS) and the observed presence of subclinical atherosclerosis in HIV-infected patients; (2) to investigate the relationships between CVD and plasma biomarkers of oxidation and inflammation. METHODS: Atherosclerosis was evaluated in 187 HIV-infected patients by measuring the carotid intima-media thickness (CIMT). CVD risk was estimated using the FRS. We also measured the circulating levels of interleukin-6, monocyte chemoattractant protein-1 (MCP-1) and oxidized low-density lipoprotein (LDL), and paraoxonase-1 activity and concentration. RESULTS: There was a weak, albeit statistically significant, agreement between FRS and CIMT (kappa=0.229, P<0.001). A high proportion of patients with an estimated low risk had subclinical atherosclerosis (n=66; 56.4%). In a multivariate analysis, the presence of subclinical atherosclerosis in this subgroup of patients was associated with age [odds ratio (OR) 1.285; 95% confidence interval (CI) 1.084-1.524; P=0.004], body mass index (OR 0.799; 95% CI 0.642-0.994; P=0.044), MCP-1 (OR 1.027; 95% CI 1.004-1.050; P=0.020) and oxidized LDL (OR 1.026; 95% CI 1.001-1.051; P=0.041). CONCLUSION: FRS underestimated the presence of subclinical atherosclerosis in HIV-infected patients. The increased CVD risk was related, in part, to the chronic oxidative stress and inflammatory status associated with this patient population.

The aqueous extract of Hibiscus sabdariffa calices modulates the production of monocyte chemoattractant protein-1 in humans.

Diet supplementation and/or modulation is an important strategy to significantly improve human health. The search of plants as additional sources of bioactive phenolic compounds is relevant in this context. The aqueous extract of Hibiscus sabdariffa is rich in anthocyanins and other phenolic compounds including hydroxycitric and chlorogenic acids. Using this extract we have shown an effective protection of cultured peripheral blood mononuclear cells from the cellular death induced by H(2)O(2) and a significant role in the production of inflammatory cytokines. In vitro, the extract promotes the production of IL-6 and IL-8 and decreases the concentration of MCP-1 in supernatants in a dose-dependent manner. In humans, the ingestion of an acute dose of the extract (10g) was well tolerated and decreased plasma MCP-1 concentrations significantly without further effects on other cytokines. This effect was not due to a concomitant increase in the antioxidant capacity of plasma. Instead, its mechanisms probably involve a direct inhibition of inflammatory and/or metabolic pathways responsible for MCP-1 production, and may be relevant in inflammatory and chronic conditions in which the role of MCP-1 is well established. If beneficial effects are confirmed in patients, Hibiscus sabdariffa could be considered a valuable traditional herbal medicine for the treatment of chronic inflammatory diseases with the advantage of being devoid of caloric value or potential alcohol toxicity.

Pitfalls in measuring high-density lipoprotein cholesterol concentrations in HIV-infected patients.

OBJECTIVES: HIV infection and its treatment are associated with dyslipidaemia and increased risk of cardiovascular disease. Accurate high-density lipoprotein (HDL) cholesterol values are necessary for the management of these abnormalities, but current methods have not been properly assessed in these patients. The aim of this study was to assess in HIV-infected patients the consistency and accuracy of a synthetic polymer/detergent homogeneous assay used to measure HDL cholesterol concentrations and to evaluate the impact of storage. METHODS: HDL cholesterol was measured using a synthetic polymer/detergent homogeneous method in samples from HIV-infected patients and healthy subjects for each of the storage regimens: baseline, after 1 week at 4 degrees C, and after 12 months at -80 degrees C. The ultracentrifugation and precipitation assays were used for comparison. RESULTS: Three out of every 20 samples from HIV-infected patients had discrepant HDL cholesterol values with respect to the ultracentrifugation method. Overestimation was associated with high C-reactive protein concentrations and underestimation with plasma gamma-globulin concentrations, an effect that was amplified by any of the storage conditions tested. CONCLUSIONS: Caution is needed when using the synthetic polymer/detergent homogeneous method for direct measurement of HDL cholesterol concentrations in HIV-infected patients. This assay is of limited use in clinical trials in which frozen samples are analysed.

Influence of a monocyte chemoattractant protein 1 mutated allele on the response to protease inhibitor-based antiretroviral therapy.

BACKGROUND: Antiretroviral drug efficacy has been widely studied in relation to viral factors. Mutations in the HIV co-receptors and their natural chemokines, however, may be critical in HIV infection and treatment response. We compared the efficacy of protease inhibitor (PI) treatment among PI-naïve patients grouped according to whether they carried the chemokine CC motif receptor 2 (CCR-2) 64I and monocyte chemoattractant protein 1 (MCP-1)-2518G alleles. METHODS AND RESULTS: HIV-infected patients who were PI-naive were selected for the study (n=164) but there was no restriction on lymphocyte CD4 count or plasma HIV viral load. Follow-up was for the first 24 months of treatment. Clinical and laboratory data were obtained every 3 months. All the participants were genotyped for the MCP-1-2518G, CCR-2 64I, CCR-5Delta32 and stromal derived factor 1 (SDF1) 3'A mutated alleles. The results indicated that patients carrying the mutated allele of MCP-1 had a higher mean CD4 cell count throughout the follow-up period than those with the common allele (P=0.01). Also, patients with the MCP-1 and CCR-2 mutated alleles were more likely to continue to have an undetectable viral load following treatment (P=0.05). CONCLUSION: A better response to PI treatment appears to be conferred by mutations in the host MCP-1 and CCR-2 genes, and may be related to the cellular axis-of-entry used by the retrovirus.

Effects of rosiglitazone on postprandial leukocytes and cytokines in type 2 diabetes.

OBJECTIVE: We postulated that in type 2 diabetes, the postprandial phase is a pro-inflammatory state that can be modulated by PPAR-gamma agonists. For this purpose, we determined the effects of rosiglitazone (8 mg/d) on postprandial leukocyte counts and pro-inflammatory cytokines (IL-6 and IL-8) in patients with type 2 diabetes. METHODS AND RESULTS: A randomized, 8-week, cross-over, placebo-controlled, double-blind clinical trial was performed in 19 patients with type 2 diabetes. Standardized 6-h oral fat-loading tests were performed after each treatment period. During placebo treatment, blood leukocytes increased to a maximum 6-h postprandially, due to significant increases in neutrophils and lymphocytes. Concomitant postprandial increases were observed for IL-6 and IL-8, the major chemokines responsible for leukocyte recruitment. Rosiglitazone reduced the incremental area under the curves (dAUCs) for IL-6 (-63%, p<0.01) and IL-8 (-16%, p<0.05). The dAUC for leukocytes decreased with 37% (p<0.05), due to a specific reduction of neutrophils (-39%, p<0.05). CONCLUSIONS: Rosiglitazone attenuated the postprandial increases of neutrophils, IL-6 and IL-8 in patients with type 2 diabetes. Since inflammation is a major force driving atherosclerosis, and man lives in a postprandial period most part of the day, a reduced inflammatory response after a meal may delay progression of atherosclerosis. CONDENSED ABSTRACT: We postulated that in type 2 diabetes, the postprandial phase is a pro-inflammatory state that can be modulated by PPAR-gamma agonists. Rosiglitazone attenuated the postprandial increases of neutrophils, IL-6 and IL-8 in patients with type 2 diabetes. These effects may contribute to cardiovascular risk reduction.

The antioxidant and hepatoprotective effects of zinc are related to hepatic cytochrome P450 depression and metallothionein induction in rats with experimental cirrhosis.

The aim of the present study was to investigate the time-course of changes in hepatic lipid peroxidation, cytochrome P450 and metallothionein concentrations, and superoxide dismutase and catalase activities in relation to the onset and development of cirrhosis in CCl4-treated rats. Further, the effects of oral zinc administration on these parameters were assessed. Cirrhosis was induced in 120 rats by intraperitoneal injections of CCl4 twice weekly over 9 weeks. Controls were 120 additional animals. Both groups were further subdivided to receive either a standard diet or one supplemented with zinc. Subsets of 10 animals each were euthanized at weeks 1, 2, 3, 5, 7 and 9 from the start of the study. Results indicated that zinc administration delayed the cirrhotic process and the increase in lipid peroxidation. These changes, consistently maintained during the first 5 weeks of the study, were associated with a significant decrease in the hepatic concentration of cytochrome P450 and an increase in the hepatic concentration of metallothioneins. Zinc supplementation did not produce any significant change in superoxide dismutase and catalase activities. These results suggest that cytochrome P450 and metallothioneins may play an important role in the hepato-protective effects of zinc against lipid peroxidation in experimental cirrhosis.

Hepatic paraoxonase activity alterations and free radical production in rats with experimental cirrhosis.

Relationships between hepatic antioxidant paraoxonase (PON1) activity, lipid peroxidation, and liver injury were investigated in rats with CCl(4)-induced cirrhosis. The study was performed in 60 CCl(4)-treated rats and 60 control animals receiving a standard diet or one supplemented with zinc. Subsets of 10 animals each were killed at weeks 1, 5, and 7 of the study. Results showed that PON1 significantly decreased in rats given CCl(4) alone compared with control animals. This effect was partially reversed in animals receiving zinc. Conversely, lipid peroxides were significantly increased in rats given CCl(4) alone and returned to approximately normal values in animals receiving zinc supplement. PON1 was inversely correlated with lipid peroxidation in all the animals studied. These alterations coincided with changes in serum alanine aminotransferase activity. In vitro incubation of isolated microsomes with CCl(4) or malondialdehyde did not produce any significant changes in PON1, indicating that the decrease in PON1 in CCl(4)-treated animals was not secondary to a direct inhibitory effect of lipid peroxidation products. These data show a time course and quantitative relationship between PON1 activity and lipid peroxidation in rats with CCl(4)-induced cirrhosis and suggest that this enzyme plays a significant role within the antioxidant systems in liver microsomes.

Instability of lipoprotein(a) in plasma stored at -70 degrees C: effects of concentration, apolipoprotein(a) genotype, and donor cardiovascular disease.

BACKGROUND: There is considerable evidence to suggest that plasma lipoprotein(a) [Lp(a)] concentration is a cardiovascular risk factor. Confusing results in epidemiologic studies, however, suggest that the effects of storage should be further investigated. The influence of the assay method, the initial plasma Lp(a) concentration, and the apolipoprotein(a) [apo(a)] genotype are all factors that should be considered. METHODS: Blood was obtained from 65 survivors of premature myocardial infarction and 95 age-matched controls. The plasma samples were stored in sterile conditions at -70 degrees C for 5 years in the presence of antioxidant and antiproteolytic substances. Plasma Lp(a) was measured by immunoturbidimetry, and apo(a) alleles were determined by pulsed-field gel electrophoresis and Southern blotting. RESULTS: Plasma Lp(a) was significantly higher in patients. The mean kringle number for the smallest isoform was also lower in patients than in controls, but no differences were found in the distribution of the largest isoform. All patients and controls were heterozygotes. During storage, mean Lp(a) decreased significantly in samples from patients (-23%; P <0.001) but not in samples from controls (-9%; P, not significant). This was not related to the kringle number and was limited to samples with initial plasma Lp(a) concentrations between 41 and 345 mg/L. CONCLUSIONS: Plasma Lp(a) from patients is less stable than Lp(a) from controls, and the difference is not related to distribution of apo(a) genotypes but may be concentration-dependent. Differential sample stability may complicate the interpretation of several studies.