Oxidative Stress and Cardiovascular Risk in Type 1 Diabetes Mellitus: Insights From the DCCT/EDIC Study

Background

Hyperglycemia leading to increased oxidative stress is implicated in the increased risk for the development of macrovascular and microvascular complications in patients with type 1 diabetes mellitus.

Methods and Results

A random subcohort of 349 participants was selected from the DCCT / EDIC (Diabetes Control and Complications Trial/Epidemiology of Diabetes Interventions and Complications) cohort. This included 320 controls and 29 cardiovascular disease cases that were augmented with 98 additional known cases to yield a case cohort of 447 participants (320 controls, 127 cases). Biosamples from DCCT baseline, year 1, and closeout of DCCT , and 1 to 2 years post‐ DCCT ( EDIC years 1 and 2) were measured for markers of oxidative stress, including plasma myeloperoxidase, paraoxonase activity, urinary F 2α isoprostanes, and its metabolite, 2,3 dinor‐8 iso prostaglandin F 2α . Following adjustment for glycated hemoblobin and weighting the observations inversely proportional to the sampling selection probabilities, higher paraoxonase activity, reflective of antioxidant activity, and 2,3 dinor‐8 iso prostaglandin F 2α , an oxidative marker, were significantly associated with lower risk of cardiovascular disease (−4.5% risk for 10% higher paraoxonase, P <0.003; −5.3% risk for 10% higher 2,3 dinor‐8 iso prostaglandin F 2α , P =0.0092). In contrast, the oxidative markers myeloperoxidase and F 2α isoprostanes were not significantly associated with cardiovascular disease after adjustment for glycated hemoblobin. There were no significant differences between DCCT intensive and conventional treatment groups in the change in all biomarkers across time segments.

Conclusions

Heightened antioxidant activity (rather than diminished oxidative stress markers) is associated with lower cardiovascular disease risk in type 1 diabetes mellitus, but these biomarkers did not change over time with intensification of glycemic control.

Clinical Trial Registration

URL : https://www.clinicaltrials.gov . Unique identifiers: NCT 00360815 and NCT 00360893.

Antibiotics from Gram-negative bacteria: a comprehensive overview and selected biosynthetic highlights

Covering: up to 2017The overwhelming majority of antibiotics in clinical use originate from Gram-positive Actinobacteria. In recent years, however, Gram-negative bacteria have become increasingly recognised as a rich yet underexplored source of novel antimicrobials, with the potential to combat the looming health threat posed by antibiotic resistance. In this article, we have compiled a comprehensive list of natural products with antimicrobial activity from Gram-negative bacteria, including information on their biosynthetic origin(s) and molecular target(s), where known. We also provide a detailed discussion of several unusual pathways for antibiotic biosynthesis in Gram-negative bacteria, serving to highlight the exceptional biocatalytic repertoire of this group of microorganisms.

Second malignancies in the context of lenalidomide treatment: an analysis of 2732 myeloma patients enrolled to the Myeloma XI trial

We have carried out the largest randomised trial to date of newly diagnosed myeloma patients, in which lenalidomide has been used as an induction and maintenance treatment option and here report its impact on second primary malignancy (SPM) incidence and pathology. After review, 104 SPMs were confirmed in 96 of 2732 trial patients. The cumulative incidence of SPM was 0.7% (95% confidence interval (CI) 0.4–1.0%), 2.3% (95% CI 1.6–2.7%) and 3.8% (95% CI 2.9–4.6%) at 1, 2 and 3 years, respectively. Patients receiving maintenance lenalidomide had a significantly higher SPM incidence overall (P=0.011). Age is a risk factor with the highest SPM incidence observed in transplant non-eligible patients aged >74 years receiving lenalidomide maintenance. The 3-year cumulative incidence in this group was 17.3% (95% CI 8.2–26.4%), compared with 6.5% (95% CI 0.2–12.9%) in observation only patients (P=0.049). There was a low overall incidence of haematological SPM (0.5%). The higher SPM incidence in patients receiving lenalidomide maintenance therapy, especially in advanced age, warrants ongoing monitoring although the benefit on survival is likely to outweigh risk.

A randomized phase III study of carfilzomib vs low-dose corticosteroids with optional cyclophosphamide in relapsed and refractory multiple myeloma (FOCUS)

This randomized, phase III, open-label, multicenter study compared carfilzomib monotherapy against low-dose corticosteroids and optional cyclophosphamide in relapsed and refractory multiple myeloma (RRMM). Relapsed and refractory multiple myeloma patients were randomized (1:1) to receive carfilzomib (10-min intravenous infusion; 20 mg/m² on days 1 and 2 of cycle 1; 27 mg/m² thereafter) or a control regimen of low-dose corticosteroids (84 mg of dexamethasone or equivalent corticosteroid) with optional cyclophosphamide (1400 mg) for 28-day cycles. The primary endpoint was overall survival (OS). Three-hundred and fifteen patients were randomized to carfilzomib (n=157) or control (n=158). Both groups had a median of five prior regimens. In the control group, 95% of patients received cyclophosphamide. Median OS was 10.2 (95% confidence interval (CI) 8.4-14.4) vs 10.0 months (95% CI 7.7-12.0) with carfilzomib vs control (hazard ratio=0.975; 95% CI 0.760-1.249; P=0.4172). Progression-free survival was similar between groups; overall response rate was higher with carfilzomib (19.1 vs 11.4%). The most common grade ⩾3 adverse events were anemia (25.5 vs 30.7%), thrombocytopenia (24.2 vs 22.2%) and neutropenia (7.6 vs 12.4%) with carfilzomib vs control. Median OS for single-agent carfilzomib was similar to that for an active doublet control regimen in heavily pretreated RRMM patients.

The risk of antimalarials in patients with renal failure

We present here a patient with end stage renal failure who received two weeks antimalarial prophylaxis at full dose leading to life threatening toxicity with severe acute megaloblastic anaemia, symptomatic pancytopenia and exfoliative dermatitis. Prompt recognition and treatment can rapidly reverse these fatal effects but more importantly, education of patients before travel is imperative in preventing such events.

Localisation of a novel region of recurrent amplification in follicular lymphoma to an approximately 6.8 Mb region of 13q32-33

Follicular lymphoma (FL) is characterised by the presence of the t(14;18)(q32;q21) and represents approximately 25% of new cases of non-Hodgkin's lymphoma. While the t(14;18) is a well-documented rearrangement, the role of secondary cytogenetic abnormalities in the development and progression of these tumours remains unclear. Comparative genomic hybridisation was used to characterise changes in DNA copy number in tumour DNA from patients with this malignancy. The mean numbers of deletion and amplification events found in each of the 45 samples studied were 1.8 and 2.3, respectively. Regions of recurrent (>10% tumour samples) gain involved chromosomes 2p13-16 (16%), 7 (20%), 12 (16%), 13q21-33 (18%), 18 (27%), and X (36%) and frequent losses localised to 6q (29%) and 17p (20%). Amplification of chromosome 13 represents a novel finding in FL. The minimal amplified region was refined to a 6.8-Mb interval of 13q32-33 between the BAC clones 88K16 and 44H20 by fluorescence in situ hybridisation studies using metaphase chromosomes derived from tumour material. There are a number of reports in the literature suggesting that amplification of chromosome 13 also occurs in other human cancers. The location of the putative oncogene on 13q described here in follicular and transformed lymphoma may also be important in the evolution of many other malignancies.

Insulin lispro lowers postprandial glucose in prepubertal children with diabetes

OBJECTIVE

This study compared the glucose-lowering effect of insulin lispro, given before or after meals, with regular human insulin given before meals in prepubertal children with diabetes.

RESEARCH DESIGN AND METHODS

A 3-way crossover, open-label study involving 61 prepubertal children (ages 2.9-11.4 years) with type 1 diabetes. The children were randomly assigned to receive regular human insulin 30 to 45 minutes before meals, insulin lispro within 15 minutes before or immediately after meals, combined with basal insulin. Each treatment lasted 3 months. Hemoglobin A(1c) levels and home glucose monitoring profiles were measured at the end of each treatment period.

RESULTS

Treatment with insulin lispro before breakfast resulted in lower 2-hour postprandial glucose values than regular human insulin (11.7 +/- 4.4 mmol/L vs 15.0 +/- 5.4 mmol/L). Similarly, insulin lispro given before dinner resulted in lower blood glucose values 2 hours postprandially (8.8 +/- 5.0 mmol/L vs 10.8 +/- 5.4 mmol/L) than regular human insulin. When insulin lispro was administered after meals, the 2-hour glucose levels were between those seen with either insulin lispro or regular human insulin given before meals. The number and types of adverse events, the rates of hypoglycemia, and the HbA(1c) levels did not differ among the 3 therapies.

CONCLUSIONS

In prepubertal children, insulin lispro given before meals is safe and significantly lowers postprandial glucose levels after breakfast and dinner compared with regular human insulin, and insulin lispro given after the meal provides similar benefits as regular human insulin before the meal.

Cyclosporin A treatment of young children with newly-diagnosed type 1 (insulin-dependent) diabetes mellitus. London Diabetes Study Group

Several studies have demonstrated the efficacy of cyclosporin A in modifying the initial course of Type 1 (insulin-dependent) diabetes mellitus in older children and adults but none have reported the effects in very young children. We treated 14 newly-diagnosed Type 1 diabetic patients aged 22 months to 95 months with cyclosporin A. Mean insulin dose at entry was 0.7 +/- 0.07 IU.kg-1.day-1. Initial cyclosporin A dose was 10 mg.kg-1.day-1. Insulin dose reached a nadir of 0.13 IU.kg-1.day-1 by 180 days. Mean glucagon-stimulated connecting peptide levels were maximal at 6 months (0.75 nmol/l) and were maintained while on cyclosporin A. Insulin was discontinued in four patients for 4, 12, 15 and 30 months respectively. In five other patients the insulin dose was less than 0.15 IU.kg-1.day-1 for at least 3 months. Glycated haemoglobin levels for all patients were within the normal range. Side effects included anorexia, stomach pains, poor weight gain, hypertrichosis, gum hyperplasia, mild anaemia and elevated creatinine. All patients have now discontinued cyclosporin A and all but one have been followed for 5 years after discontinuation. Reasons for discontinuing cyclosporin A included exposure to chicken pox (varicella), non-resolving otitis media, incomplete or no response and relapse. All side effects have resolved since the treatment was discontinued. Following discontinuation of cyclosporin A insulin requirements and glycated hemoglobin levels increased while glucagon-stimulated connecting peptide levels declined dramatically.(ABSTRACT TRUNCATED AT 250 WORDS)

Clinical trials of cyclosporin in IDDM

The results of uncontrolled trials in immunomodulation of insulin-dependent diabetes mellitus (IDDM) led to randomized controlled trials in Canada and Europe. In the Canadian open study, the rate of clinical remissions (target control of glycemia maintained with less than or equal to 0.15 U.kg-1.day-1 insulin) was unexpectedly high among 81 subjects who had been treated with cyclosporin for at least 3 mo (mean serum trough levels approximately 125 ng/ml by radioimmunoassay). Subjects entered the study within 14 wk of onset of symptoms and received 6 wk of insulin therapy. The clinical remission rate at 1 yr was 46%; of these patients, 84% were not receiving insulin. An effect on beta-cell function was suggested by recovery of plasma glucagon-stimulated C-peptide levels into the normal range in many patients, with maintenance of levels through 1 yr in patients in remission. On the basis of these findings, the French and Canadian-European study groups conducted randomized double-blind controlled trials of cyclosporin, which confirmed the results of the open studies in terms of clinical remission. The Canadian-European study also demonstrated enhancement of beta-cell function by cyclosporin by 3 mo, which was maintained for 1 yr. In the Canadian open study, most patients relapsed within a few weeks after discontinuation of cyclosporin, indicating the need for longer-term immunomodulatory therapy for maintenance of remission. The nature and degree of structural change in kidney biopsies from patients in these studies are under assessment. The results strongly support the hypothesis that autoimmune mechanisms mediate beta-cell damage in many patients with IDDM.(ABSTRACT TRUNCATED AT 250 WORDS)

Intensive care course following liver transplantation in children

We report the postoperative intensive care course of 16 children who underwent 18 orthotopic liver transplantation (OLT) procedures in London, Ontario and compare this experience in our developing transplant center with that reported from the Children's Hospital of Pittsburgh. Assisted ventilation was required in all children, with six requiring ventilation for greater than three days. Six children required positive end expiratory pressure (PEEP) therapy and hypertension was common. Physiologic stability index score was initially high in all patients, but fell on subsequent days. Intensive care survival was 100% with 69% long-term survival, which compared favorably with the information from Pittsburgh. Septic complications, despite immunosuppressive therapy were rare, but hypocalcemia and hypomagnesemia were common.

Orthotopic liver transplantation in children

Ten children, aged 3 to 16 years, were part of a group of 61 patients who received liver transplants at University Hospital in London, Canada between November 1982 and April 1986. All of the children received cyclosporine in combination with other agents for immunosuppression. Two children died of rejection, one child died from a lymphoma, and one child died from a hypoxic brain injury sustained during a respiratory arrest. Six children are currently alive from 4 months to 2 1/2 years following transplantation. All of the survivors have returned to a normal life style. With current surgical techniques and modern immunosuppression, hepatic transplantation has become the treatment of choice for patients with endstage irreversible liver disease. The extreme shortage of donor organs is now the major factor limiting the application of liver transplantation in children.

The effect of isolation stress on some hepatic drug and carcinogen metabolising enzymes in rats

Rats were subjected to stress by isolation for periods of up to eight days, which produced an elevation in plasma cortisol. In vivo drug metabolism as estimated by the plasma elimination rate of orally-administered antipyrine was not significantly affected by this treatment although there was an apparent decrease in the absorption rate of the drug. In vitro experiments on hepatic microsomal preparations derived from stressed animals indicate that this stress increased in the activity of some enzyme systems concerned with benzo(a)pyrene activation and this correlated with an increased binding of the carcinogen to DNA. The activity of conjugating enzyme which could catalyze the excretion of such carcinogens was not significantly altered. The results indicated that stress could have an important bearing on carcinogenesis by enhancing to a greater extent enzyme systems responsible for activation than those involved in the excretion of polycyclic aromatic hydrocarbons.

The effect of chloroform inhalation on hepatic glucuronidation and de-glucuronidation mechanisms

The effect of 2, 4, 6 or 8 exposures to chloroform vapour on hepatic glucuronidating (UDPGA transferase) and de-glucuronidating (beta-glucuronidase) levels has been studied in rats. Successive treatments progressively decreased hepatic UDPGA transferase to a minimum of 53% of the control level. beta-Glucuronidase activity was increased two-fold after only two exposures and remained elevated for subsequent exposures. Cytochrome P450 levels decreased with each exposure. The level of this coenzyme in the treated animals remained lower than that of the control animals for at least 48 hours after treatment. UDPGA transferase was diminished to its lowest levels 9 hours after the final exposure to chloroform and did not achieve the control value for a further 48 hours. The beta-glucuronidase activity remained elevated for 12 hours after final exposure. The present experiment demonstrates that inhalation of toxic solvents such as chloroform decreases the glucuronidating capacity of the liver.

Effects of several preoperative medications on fat cell lipolysis, and activity of adipose tissue cyclic AMP phosphodiesterase

Effects were examined of atropine, diazepam, pethidene, promethazine, scopolamine, omnopon and papaverine on basal and noradrenaline-stimulated lipolysis in rat isolated fat cells and on rat adipose tissue cyclic AMP phosphodiesterase activity. Papaverine at high concentration (1 mM) inhibited both basal and hormone-stimulated lipolysis, whereas diazepam enhanced basal lipolysis. At a 'clinical dose', omnopon increased both basal and noradrenaline-stimulated lipolysis. Adipose tissue cAMP phosphodiesterase activity was strongly inhibited by 1 mM diazepam, papaverine, promethazine and omnopon (280 microgram ml-1). Lack of enhancement of lipolysis by the established cAMP phosphodiesterase antagonist papaverine, is compatible with simultaneous inhibition also of adipose adenyl cyclase. Diazepam-stimulated lipolysis is compatible with its phosphodiesterase inhibitory activity. It is proposed that papaverine-containing omnopon may offer some survival advantages during surgical stress by facilitating a caloric supply.

Hepatic function assessed (in rats) during chemotherapy with some anti-cancer drugs

Using rats, we studied how best to assess hepatic damage after administering therapeutic doses of each of five anti-cancer drugs or of the hepatotoxin, carbon tetrachloride. As indexes, we compared measurement of the concentration of administered antipyrine in plasma with measurement in serum of alpha-fetoprotein or of the activities of five enzymes that reportedly best reflect hepatic damage. The biological half-life of antipyrine in the plasma was increased more than threefold on pretreating the rats with any of the five cytotoxic drugs or with carbon tetrachloride. In contrast, the concentrations of alpha-fetoprotein, alkaline phosphatase, gamma-glutamyltransferase, or glutamate dehydrogenase were not consistently increased. Of the enzymes tested in serum, aspartate aminotransferase and ornithine carbamoyltransferase best indicated hepatic impairment resulting from the treatment with anti-cancer drugs. Our results imply that determination of the pharmacokinetics of marker drugs such as antipyrine better indicates hepatic dysfunction induced by cytotoxic agents than does measurement of the enzymes liberated into serum as a result of damage to liver mitochondria.

Hepatic function assessed (in rats) during chemotherapy with some anti-cancer drugs

Using rats, we studied how best to assess hepatic damage after administering therapeutic doses of each of five anti-cancer drugs or of the hepatotoxin, carbon tetrachloride. As indexes, we compared measurement of the concentration of administered antipyrine in plasma with measurement in serum of alpha-fetoprotein or of the activities of five enzymes that reportedly best reflect hepatic damage. The biological half-life of antipyrine in the plasma was increased more than threefold on pretreating the rats with any of the five cytotoxic drugs or with carbon tetrachloride. In contrast, the concentrations of alpha-fetoprotein, alkaline phosphatase, gamma-glutamyltransferase, or glutamate dehydrogenase were not consistently increased. Of the enzymes tested in serum, aspartate aminotransferase and ornithine carbamoyltransferase best indicated hepatic impairment resulting from the treatment with anti-cancer drugs. Our results imply that determination of the pharmacokinetics of marker drugs such as antipyrine better indicates hepatic dysfunction induced by cytotoxic agents than does measurement of the enzymes liberated into serum as a result of damage to liver mitochondria.

Plasma prostaglandin levels in fed and starved lean, normal and obese women

The plasma obtained from fed and starved lean, normal and obese women was estimated, by a radio-immunoassay method, for prostaglandins, owing to their implication in the regulation of adipose tissue lipolysis and the development of obesity. No significant differences were found due to nutritional status or body-build. However, a significantly higher plasma concentration of prostaglandins of the E-type than of the F-type, was found consistently. The very low levels of prostaglandins observed (a range of 0.10--0.15 ng ml-1 for E-type and a range of 0.05--0.07 ng ml-1 for the F-type) may be due, in part, to the activity of a plasmatic prostaglandin metabolizing system.

Correlation between tumour size, metastatic spread and galactosyl transferase activity in cyclophosphamide-treated mice bearing the Lewis lung carcinoma

Galactosyl transferase activity was measured in tumour and normal tissues of mice receiving cyclophosphamide treatment for Lewis lung carcinoma. Animals which responded to cyclophosphamide therapy had significantly smaller tumours with fewer metastases than the untreated mice. The level of galactosyl transferase was significantly reduced in the tumours which were inhibited by the cyclophosphamide treatment.

The effect of chronic ethanol intake on the growth and spread of some murine tumors

The effect of chronic ethanol intake on the growth and spread of some murine tumors has been investigated. The treatment had no effect on the B 16 melanoma but tended to decrease the number of Ehrlich ascites cells. In the case of the Lewis lung carcinoma, administration of ethanol for two weeks tended to lower the number of metastases to the lung without significantly affecting the primary tumor size, whereas more prolonged ethanol intake decreased the weight of the primary tumor in addition to decreasing its dissemination.

The effect of chronic alcohol intake upon the hepatic microsomal carcinogen-activation system

Ethanol was administered to mice either by repeated intraperitoneal injection, or orally in the drinking water over an extended period of time. Following intraperitoneal ethanol pre-treatment further groups of mice received an injection of benzo(a)pyrene. Alcohol intake decreased the level of microsomal aryl hydrocarbon hydroxylase which corresponded to the observed decrease in DNA binding of benzo(a)pyrene. In contrast, the number of tumors which developed in the alcohol pre-treated mice exceeded those of the control animals.