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.

A case of chromomycosis treated by a combination of cryotherapy, shaving, oral 5-fluorocytosine, and oral amphotericin B

A case of chromomycosis from Comoro Islands was first treated without success with high doses of oral amphotericin B (3 g per day). Treatment with itraconazole (400 mg per day) was also unsuccessful. Then, in vitro tests were done to study the susceptibility of this Fonsecaea pedrosoi strain to antifungal drugs. It was resistant to itraconazole, sensitive to 5-fluorocytosine, and the combination of 5-fluorocytosine with amphotericin B was synergistic. The patient was then treated with this last combination of drugs, which seemed to be effective. The patient stopped this treatment after six months, and relapse occurred two years later. The best therapeutic strategy in cases of chromomycosis seems to be a combination of two drugs chosen according to the results of prior antifungal susceptibility testing.

Combined anti-fungal therapy and surgical resection as treatment of pulmonary zygomycosis in allogeneic bone marrow transplantation

Opportunistic fungal infection is a rare but severe complication in allogeneic bone marrow transplant (BMT) recipients. We report a 49-year-old patient who developed pneumonitis after BMT, due to a Mucorales fungus (class Zygomycetes), Absidia corymbifera. Infections due to mucormycosis are likely to become increasingly recognized even though the occurrence after BMT has only been described sporadically. We postulate that the patient was contaminated before BMT despite no intensive drug treatment or other iatrogenic features, related to his poor living conditions and developed the infection during aplasia. He immediately received i.v. liposomal amphotericin B (AmBisome) and GM-CSF. Because there was no response, the infected area and necrotic tissue were resected. Despite initial clinical and biological improvement and the absence of Mucor on mycological examination post-surgery, the patient died 3 weeks later from bilateral pulmonary infection and multiorgan failure.

New enzyme immunoassays for sensitive detection of circulating Candida albicans mannan and antimannan antibodies: useful combined test for diagnosis of systemic candidiasis

Two standardized enzyme immunoassays for the serological diagnosis of candidiasis were developed. The first one detects antimannan antibodies, while the second one detects mannan with a sensitivity of 0.1 ng/ml. These tests were applied to 162 serum samples retrospectively selected from 43 patients with mycologically and clinically proven candidiasis caused by Candida albicans. Forty-three serum samples were positive for mannan, and 63 had significant antibody levels. Strikingly, only five serum samples were simultaneously positive by both tests. When the results were analyzed per patient, 36 (84%) presented at least one serum positive by one test. For 30 of them, positivity by one test was always associated with negative results by the other test for any of the tested sera. For six patients whose sera were positive for either an antigen or an antibody response, a balance between positivity by each test was evidenced by kinetic analysis of sera drawn during the time course of the infection. Controls consisted of 98 serum samples from healthy individuals, 93 serum samples from patients hospitalized in intensive care units, and 39 serum samples from patients with deep mycoses. The sensitivities and specificities were 40 and 98% and 53 and 94% for mannanemia or antibody detection, respectively. These values reached 80 and 93%, respectively, when the results of both tests were combined. These observations, which clearly demonstrate a disparity between circulation of a given mannan catabolite and antimannan antibody response, suggest that use of both enzyme immunoassays may be useful for the routine diagnosis of candidiasis.

Specific antibody response to oligomannosidic epitopes in Crohn's disease

Elevated antibody levels against the yeast Saccharomyces cerevisiae have been reported in sera from patients with Crohn's disease and not with ulcerative colitis. The aim of the study was to identify the nature of the epitopes supporting this antibody response. Whole cells from different S. cerevisiae strains were selected in immunofluorescence assay for their ability to differentiate the antibody responses of patients with Crohn's disease and ulcerative colitis. Their cell wall phosphopeptidomannans were then tested as antigen in enzyme-linked immunosorbent assay (ELISA) against sera from 42 patients with Crohn's disease, 20 patients with ulcerative colitis, and 34 healthy controls. Graded chemical degradations were performed on the most reactive strain phosphopeptidomannan. The discriminating epitope was determined through gas-liquid chromatography-mass spectrometry. The greatest discrimination among patients with Crohn's disease, ulcerative colitis, and controls was obtained with Su1, a S. cerevisiae strain used in brewing of beer. ELISA directed against phosphopeptidomannan of this strain was 64% sensitive and 77% specific for discriminating Crohn's disease versus ulcerative colitis and 71% sensitive and 89% specific for Crohn's disease versus controls. Periodate oxidation and selective degradation demonstrated that the most important polysaccharide epitope was shared by both the acid-stable and the alkali-labile domains of the phosphopeptidomannan. The determination of oligomannose sequences of S. cerevisiae Su1 phosphopeptidomannans suggested that a mannotetraose, Man (1 --> 3)Man(1 --> 2)Man(1 --> 2)Man, supported the serological response seen in Crohn's disease. Further identification of the immunogen eliciting this antibody response as a marker of the disease may help to understand its etiology.

Retrospective evaluation of two latex agglutination tests for detection of circulating antigens during invasive candidosis

Two latex agglutination tests for the detection of Candida antigens, Pastorex Candida (Sanofi Diagnostics Pasteur, Marnes-la-Coquette, France) and Cand-Tec (Ramco Laboratories, Inc., Houston, Tex.), were applied to 79 serum samples from 19 patients who were retrospectively selected on the basis of mycological and clinical evidence of C. albicans infection and the availability of serial serum samples taken near the date of a positive culture. The specificity in 60 control individuals was 100% for Pastorex and 98.3% for Cand-Tec. The tests scored positive for 10 (52.6%) and 9 (47.4%) patients, respectively. Pastorex detected antigen in only 3 of 12 patients (25%) with positive antibody detection tests, but was positive for all 7 patients (100%) who produced no or a low antibody response, suggesting that the test performs better in the absence of antibodies. However, the sensitivity of Pastorex also increased with the number of samples available per patient, which was lower for high-antibody-responder patients (2.8 versus 5.7). If the patients who provided only one or two serum samples were eliminated, the sensitivity of Pastorex rose to 76.9%. For the Cand-Tec, the sensitivity was not related to the presence of antibodies, nor was it related to the number of samples per patient. The observed antigenemia was transient with both Pastorex and Cand-Tec. Only 12.5% of the positive reactions occurred on the same serum sample, confirming that the two tests react with different antigens. A positive antigen test preceded other diagnostic indications for 6 of 10 Pastorex-positive patients and 5 of 9 Cand-Tec-positive patients.

Kinetic study of antifungal activity of amphotericin B, 5-fluorocytosine and ketoconazole against clinical yeast isolates using liquid-phase turbidimetry

The fungal growth of clinical yeast isolates and of VW32 clone of Candida albicans were measured in vitro using a liquid-phase turbidimetric system (Bioscreen from Labsystems, France) in defined conditions. Cultures were performed in Shadomy's liquid medium and the fungal growth automatically evaluated every 10 minutes for 24 hours using various concentrations of drugs. The system made it possible to test 200 culture samples in one experiment. Yeast sensitivity to drugs was also measured by using our routine semi-automatic turbidimetric system. We observed that kinetic patterns of activity of each antifungal agent were typical. The in vitro tests showed that of 927 clinical yeast isolates 99.2% were sensitive to amphotericin B, 94.4% to 5-fluorocytosine and 69.7% to ketoconazole.

Expression of an epitope by surface glycoproteins of Candida albicans. Variability among species, strains and yeast cells of the genus Candida

Expression of an antigenic epitope reactive with an IgM monoclonal antibody was studied in 253 Candida isolates by direct agglutination. Isolates of Candida albicans reacted significantly more often with the antibody than did isolates of other species. The agglutination scores for C. albicans isolates from sources associated with possible deep-seated Candida infection were significantly higher than for those from other sources. However, there was considerable overlap of scores between these two groups so that the functional significance of the association is uncertain. There were no associations between agglutination score and C. albicans biotype: multiple isolates from individual patients gave similar agglutination scores. Expression of the epitope within colonies of cloned strains was studied by autoradiography of colony blots on nitrocellulose and by immunoperoxidase staining of colonies in situ. It was found that the epitope was expressed variably by portions of colonies of both agglutination-positive and agglutination-negative strains. Indirect immunofluorescence revealed that expression of the epitope at the surface of C. albicans germ tubes and their associated buds was variable from cell to cell. It was not directly related to morphology or stage of growth of the cells.

Diagnosis of systemic candidiasis: application of co-counterimmunoelectrophoresis

The accuracy of co-counterimmunoelectrophoresis was compared with mycological and clinical data for different groups of inpatients. The specificity and sensitivity of this method ranged from 100 to 69%. The co-specific precipitin line was observed during systemic infections caused by most opportunistic Candida species. The variations in the line in successive serum samples provided a simple means of serological surveillance. The test also detected seroconversion. The gradual disappearance of the line reflected a favourable prognosis, whereas its abrupt disappearance indicated unfavourable prognosis and correlated with the appearance of detectable circulating antigens.

Scedosporium (Monosporium) apiospermum: multiple brain abscesses

A 32-year-old female with alcoholic cirrhosis attempted to drown herself in a pond. She remained in a coma for 57 days. After a stormy course she developed multiple brain abscesses due to Scedosporium (Monosporium) apiospermum. Despite intravenous and intrathecal amphotericin B (total dose 870 mg) the patient died 71 days after the near drowning.

[Fungal infections: involved species and minimal inhibitory concentrations of common antifungal agents]

Fungal cultures of cutaneous or ungual origin (477 cultures), nasopharyngeal and urogenital origin (2,000 cultures), and blood, internal organs, surgical incisions, and catheters (300 cultures) were obtained in this study. Analysis of the data yielded the following information: Candida albicans and C. tropicalis, frequent causes of superficial or systemic mycoses, were very sensitive to flucytosine and amphotericin B in a liquid medium, but less sensitive to the imidazole derivatives; C. parapsilosis, a cause of superficial and systemic mycoses, was remarkably sensitive to all four antifungal agents tested; Torulopsis glabrata and C. krusei are of greatest concern in a hospital setting since systemic or visceral infections are minimally sensitive to antifungal agents; C. pseudotropicalis, C. guilliermondii, and C. zeylanoides are less pathogenic and sensitive to antifungal agents varies, depending on the strain. Specific measures are presented for management of fungal infections in a hospital setting. The role of antifungal susceptibility testing in everyday practice is also evaluated.

Peanut agglutinin affinity chromatography of Trypanosoma cruzi glycoproteins

Glycoproteins from Trypanosoma cruzi epimastigotes have been extracted by diiodosalycilic acid and lithium salts, and phenol-water biphasic partition. Peanut agglutinin has been used in a one step preparative method for fractionating the total extract in order to separate the so-called galactose-terminal glycoproteins. The different fractions have been studied by SDS electrophoresis, ultracentrifugation and immunoelectrophoresis techniques. The experimental immunogenicity, antigenicity and specificity of the PNA affinity fractions has been evaluated.

Antigenic make-up of Trypanosoma cruzi culture forms: identification of a specific component

A comparison of Trypanosoma cruzi water soluble antigens with those of stercorarian and salivarian trypanosomes, and Leishmania using immunoprecipitation in gels and immunoelectrophoresis, with the aid of hyperimmune rabbit serum and heterologous adsorptions showed the following. 1) There is a high complexity of soluble antigens of T. cruzi and T. rangeli. 2) At the intraspecific level our results demonstrated the antigenic stability of T. cruzi when maintained in vitro, and that there was quantitative antigenic consistency of the culture forms of different strains of T. cruzi from diverse geographic and parasite sources. At the interspecific level, the antigenic relationships between T. cruzi and the other Trypanosomatidae were established, as follows: 6/10ths of the antigens are shared by stercorarian species (T. dionisii, T. rangeli); 4/10ths by a salivarian trypanosome (T. brucei); and 3/10ths by Leishmania (L. donovani, L. mexicana). 3) Among the 4/10ths of antigenic components specific to T. cruzi, one component was characterized by its antigenicity and immunogenicity in natural and experimental infections, and in immunization experiments; this component was specific to T. cruzi when compared to the other Trypanosomatidae antigens.

Purification of a specific antigen of Trypanosoma cruzi from culture forms

A monospecific rabbit antiserum was prepared against a specific component of Tryanosoma cruzi epimastigote culture forms (designated antigen 5). Rabbits were immunized intradermally in 30-50 sites with the zone of agarose gel in which the component 5:anti-5 complex was visualized after two-dimensional immunoelectrophoresis. With this appropriate antiserum and the total epimastigote soluble extracts, the specific component of T. cruzi was purified by immunoadsorption. Purity and specificity controls of thefinal product were carried out by prolonged immunization of rabbits, and then by immunoelectrophoretic and two-dimensional electrophoretic analyses.

Identification and purification of the specific antigen of Paracoccidioides brasiliensis responsible for immunoelectrophoretic band E

A new purified antigen (E2) of Paracoccidioides brasiliensis mycelial growth phase was isolated by immunoadsorption from a crude metabolic soluble extract of the fungus. The antiserum prepared in a rabbit by inoculation of E2 antigen developed only one immunodiffusion line with the crude metabolic extract. Findings on immunological analysis showed that E2 antigen is the antigenic component of immunoelectrophoretic band E. The isolated antigens did not possess detectable alkaline phosphatase activity. It reacted in immunodiffusion tests with all the sera (14/14) from P. brasiliensis infected patients containing precipitating antibodies.

Antigenic analysis of a variant specific component of Trypanosoma Brucei Brucei I -- Immunochemical purification by affinity chromatography

An antigenic component specific to the bloodstream form of serotype AnTat-1 of Trypanosoma brucei brucei was purified by immunoadsorption technique. Subsequently, a monospecific rabbit antiserum was prepared. Purity and specificity controls of the final product were carried out by immunoelectrophoretic analysis.

[Comparative immunoelectrophoretic analysis of culture and bloodstream forms of "trypanosoma" (Trypanozoon) brucei gambiense". Demonstration of stage and antigenic type specific antigens (author's transl)]

The comparative immunoelectrophoretic analysis of the antigenic structures of culture and bloodstream forms with cross absorption tests confirm the existence among Trypanosoma gambiense antigens of: --numerous antigenic components common to culture and bloodstream forms;--several antigenic components specific of either culture forms or bloodstream forms. Among the latter, two components are shown to be specific of the antigenic type and appear to support the immunochemical specificity of each variant.