Low-dose aspirin for primary prevention of cardiovascular events in patients with diabetes: Benefit or risk?

Primary prevention aims to avert the onset of cardiovascular disease (CVD) by targeting its natural causes and risk factors; secondary prevention includes strategies and therapies that address preclinical or clinical evidence of CVD progression. The value of aspirin for primary CVD prevention is controversial because of increased bleeding, which may offset the overall modest benefits in patients with no overt CVD. In contrast, the benefits of aspirin for secondary prevention have been repeatedly and convincingly demonstrated to outweigh the risk of bleeding. Diabetes mellitus is a strong risk factor for cardiovascular events, and has been associated with an increased risk of both first and recurrent atherothrombotic events. Therefore, prevention of CVD, the major cause of mortality in patients with diabetes, is one of the most important therapeutic goals. Although the benefit of low-dose aspirin for secondary prevention of CVD is well established, its role for primary prevention remains inconclusive and controversial in diabetes patients. The benefit of aspirin for patients with CVD clearly exceeds the risk of bleeding, and even though a modest benefit has also been demonstrated in primary prevention, the trade-off for aspirin initiation against the increased risk of intracranial and gastrointestinal bleeding is more uncertain. Thus, aspirin for primary CVD prevention should be highly individualized, based on a benefit-risk ratio assessment for the given patient. In conclusion, the mere presence of diabetes is apparently not enough for aspirin to confer a benefit that clearly outweighs the risk of bleeding, and further evidence to the contrary is now needed.

CEA versus CAS: short-term and mid-term results.

AIM: Ischemic stroke represents a major health problem and it is an important cause of long-term disability. The aim of this study was to compare short-term and mid-term results of carotid endarterectomy and stenting. METHODS: During a three-year period, we enrolled 300 patients with carotid stenosis that fit with Stroke Prevention and Educational Awareness Diffusion (SPREAD) guidelines and we performed 150 carotid endarterectomy operations (CEA) and 150 carotid artery stenting procedures (CAS) with distal protection devices. All patients underwent preoperative and postoperative: neurological examination, ultrasound imaging, magnetic resonance imaging (MRI) and cognitive tests; moreover all patients were submitted to preoperative, intraoperative and postoperative Transcranial Doppler (TCD) monitoring, in order to detect microembolic signals (MES). RESULTS: Mortality was zero; two patients developed myocardial infarction in the CEA group during follow-up. The main post-operative results after endarterectomy versus CAS were respectively: neurological deficit: 1.3% vs. 3.3%, embolic lesions at postoperative MRI: 4% vs. 34% and worsening of cognitive tests: 4% vs. 25.3%. CONCLUSION: CEA seems to be the treatment of choice for carotid stenosis, due to its low rate of mortality and morbidity, especially in asymptomatic patients; CAS should be carried out only in particular subgroup of cases, such as: restenosis, previous neck surgery or radian therapy, anatomical high bifurcation or extended lesions. Ongoing multicenter randomized trials may give a definitive answer to this matter.

Establishing of a minimal set of tests (minimal standards) to identify species included in the genus Mycobacterium.

Mycobacterium genus includes over 100 species and subspecies; new species are discovered every year. Minimal standard criteria are represented by the resistance to acid-alcohol (e.g. in the Ziehl - Neelsen staining), the presence of some mycolic acids containing 60-90 carbon atoms that can be cleaved by pyrolysis in fatty acids with 22 - 26 carbon atoms and a guanine + cytosine content of the DNA of 61 to 71 mol %. The species with the highest rate of involvement are those from Mycobacterium tuberculosis complex, and tuberculosis is still one of the most widespread world diseases. The most important for a laboratory is to be able to identify the species from M. tuberculosis complex. We have done a series of experiments, their goal being to evaluate and establish a minimal set of useful tests for identification of mycobacterial species. We used strains from "Cantacuzino" Institute collection and applied a series of classical and modern methods. We appreciate that the minimal set of tests could be represented by the microscopic examination for acid-fast bacilli (AFB), the examination for the preferred growth temperature, the growth rate, the colonies morphology, pigmentation and photo reactivity, the niacin accumulation test, the test of nitrate reduction, the catalase test (in both variants), plus the susceptibility to Para-Amino Salicylic Acid, Para-Nitro-Benzoic Acid andto Tiophene-2-Carboxylic Acid Hydrazide.

Application of ELISA with antigenic glycolipids in early diagnosis of pulmonary tuberculosis.

Antibodies against M. tuberculosis antigenic glycolipids were determined by enzyme-linked immunosorbent assay (ELISA) in 80 sera from patients suspected of pulmonary tuberculosis, with suggestive clinical signs and radiological abnormalities, but smears negative. The test was also performed on 68 control sera from patients with bacteriologically confirmed pulmonary tuberculosis, in different stages of disease. We obtained the test sensitivity of 89.5% for the confirmed tuberculosis patient sera. Low levels of specific antibodies and the sensitivity of 75% were found when using ELISA in smears negative patients at the onset of clinical tuberculosis. The experimental results showed that ELISA could be used as a supporting test in early diagnosis of pulmonary tuberculosis.

Serodiagnosis of tuberculous meningitis by enzyme-linked immunosorbent assay (ELISA).

IgG antibodies against glycolipids and proteins isolated from M. tuberculosis and BCG suspension were determined by ELISA in sera, in CSFs and in serum and CSF paired samples, from patients with tuberculous meningitis and from healthy control subjects. With specificities between 90 and 94% for the antigens used, we obtained senitivities of 75% for Pr-ELISA, 60% for G1-ELISA and 35% for BCG-ELISA. As specific antibodies were detected in serum and CSFs, only one sample is enough to perform the test. We concluded that Pr-ELISA and G1-ELISA could be used as a supporting test in TBM diagnosis, especially when repeated bacteriological methods failed to prove the presence of tubercle bacilli and in cases without evidence of pulmonary tuberculosis.

Evidence for tuberculous infection in Romanian HIV-positive children by enzyme-linked immunosorbent assay.

The pandemic spread of tuberculosis (TB) and human immunodeficiency virus (HIV) represents a serious world problem. The diagnosis of TB in developing countries remains difficult, particularly in patients with concomitant HIV infection. Anergia to tuberculin frequently occurs in HIV-positive patients with pulmonary or extrapulmonary disease, and radiographic images are atypical or nondiagnostic. Children are often in an even more unfavorable situation: they cannot expectorate, and the biological samples required for bacteriological examination and culture are more difficult to obtain. We present in this work the correlation between the presence of serum antimycobacterial antibodies [as demonstrated by an in-house enzyme-linked immunosorbent assay (ELISA)] in 41 out of 279 HIV-infected children, and clinical, bacteriological, radiological, and pathological data that support the diagnosis of TB in these children. The prevalence of antimycobacterial antibodies in our group of HIV-positive children was 23.3%. In only 4 of the total cases investigated could the diagnosis of TB not be supported by the results of standard tests for TB. The control group showed an insignificant interference from bacillus Calmette-Guerin (BCG) vaccination.

Clinical usefulness of rapid serodiagnosis in pulmonary tuberculosis by ELISA with glycolipidic antigens extracted from Mycobacterium tuberculosis and with whole BCG suspension.

Antibodies against Mycobacterium tuberculosis glycolipids and whole BCG suspension were determined by ELISA on 58 sera from hospitalized patients with presumptive pulmonary tuberculosis and on 127 sera from control subjects. The experimental results demonstrated that the glycolipids are more adequate to be used as antigens than whole BCG suspension, as high sensitivity of the test was obtained. By using only one antigen, ELISA becomes more efficient in rapid diagnosis. ELISA with glycolipidic antigens should be used as a supporting test for direct smear examination in the diagnosis of pulmonary tuberculosis, especially in cases when repeated bacterial methods failed to prove the presence of M. tuberculosis.

Humoral immune response in human pulmonary tuberculosis: antibodies against Mycobacterium tuberculosis polysaccharide, protein and glycolipid antigens.

Sera from 67 tuberculosis patients and 30 healthy subjects have been analyzed for the presence of specific antibodies against polysaccharide, protein and glycolipid antigens from H37Rv strain of Mycobacterium tuberculosis. The results proved the advantages of using the glycolipid antigens in diagnosing tuberculosis as well as the relationship between the antibodies level and the extension of the pulmonary tuberculous lesions.

Specific antibodies and mycobacterial antigens in pulmonary tuberculosis patients sera. Note I.

206 sera collected from different groups of subjects were analyzed by immunoenzymatic methods regarding the content of Mycobacterium tuberculosis specific antibodies and mycobacterial antigens. The results underlined that two assays offered improved serologic diagnosis of tuberculosis over a single antibody test. BCG vaccination interferes with serologic tests for tuberculosis when polyspecific antibodies or mixture of common and specific antigens are used as immunologic reagents. A mycobacterial antigens circadian variation in correlation with vesperal fever in tuberculous patients was not revealed. The mycobacterial antigens seem to become undetectable, in sera, after 6 months of efficient treatment.

Specific antibodies and mycobacterial antigens in patient sera with pulmonary tuberculous and nontuberculous diseases. Note II.

"Two-assay" tests (TAT), immunoenzymatic determination of both specific antibodies and mycobacterial antigens in sera of tuberculous and non-tuberculous subjects, was undertaken in our territorial conditions, where BCG vaccination is systematically applied and the prevalence of tuberculous infection is relatively high. The sensitivity of the method, calculated on 42 patients with active pulmonary tuberculosis and on 39 patients with post-tuberculosis syndromes is high, i.e. 0.952. The specificity of the method separately calculated for 44 young subjects (under 21 years old), for 78 healthy adults and for 201 lung diseased patients, bacteriologically not ascertained as tuberculosis at the moment of sera prelevation, varied between 0.830 and 0.489. "TAT", performed with crude immunologic reagents, produces false-positive reactions in early BCG vaccinated subjects. Method specificity low values in pulmonary non-tuberculous patients group may be partially explained by the difficulty in establishing the real relationships, in time, between host and mycobacteria, by the bacteriological method imperfections or sample prelevating methods. Our results certainly underestimate the diagnosis value of "TAT".