Osteomyelitis: clinical update for practical guidelines

Bone infections represent a diagnostic or therapeutic challenge for the infectivologist, orthopaedic surgeon, radiologist and nuclear medicine physician. Staphylococcus aureus is the major bacterium responsible for bone infections although Mycobacterium tuberculosis is emerging as an infectious agent in Italy because of immigration from Africa and Asia. Osteomyelitis requires long and expensive antibiotic treatment, including rifampicin administered parenterally for several weeks and the use of antimicrobial-impregnated cement in prosthesis substitution. Sometimes it is necessary to carry out surgical debridement of a necrotic bone or the consolidation of compromised bones and joint prosthesis implants. Radiographs and bone cultures are mainstays for the diagnosis of bone infections but are often useless in the lengthy management of these patients. Diagnosis of skeletal infections still includes conventional radiography but magnetic resonance imaging is essential in haematogenous and spinal infections. Bone scans are still useful in acute osteomyelitis whereas scintigraphy using labelled white blood cells is preferred in infections of peripheral bone segments or joint prosthesis. In the axial skeleton a combination of an agent for detecting inflammation ((67)Ga citrate) and a metabolic agent ((99m)Tc-methylene diphosphonate) enables an infection and an area of increased metabolic activity to be distinguished. [(18)F]Fluorodeoxyglucose positron emission tomography, where available, has a significant impact in the study of infections using radionuclides: high-resolution tomographic images represent an effective alternative to gallium in the assessment of inflammation of spine lesions but a comparison with morphological examinations (computed tomography or magnetic resonance imaging) is essential.     

Detection of anti-Saccharomyces cerevisiae antibodies in Crohn's disease: is it reliable diagnostic and prognostic marker?

Background. In the past few years, serologic markers have been proposed in inflammatory bowel disease. Anti-Saccharomyces cerevisiae antibodies showed high specificity for Crohn's disease. A prognostic role for serology has also been hypothesised.Aims To evaluate anti-Saccharomyces cerevisiae antibody distribution in an unselected Italian inflammatory bowel disease population. To analyse whether anti-Saccharomyces cerevisiae antibody status (positive/negative) and/or anti-Saccharomyces cerevisiae antibody titres are associated with clinical variables and outcome measures in Crohn's disease patients.Patients and Methods. A series of 299 inflammatory bowel disease patients were evaluated; serum samples were taken and a short clinical history was recorded. anti-Saccharomyces cerevisiae antibodies IgG enzyme-linked immunosorbent assay Medilab® (Milan, Italy) kit was used in order to determine anti-Saccharomyces cerevisiae antibody status.Results. Sensitivity, specificity and likelihood ratio for positive test in the differential diagnosis of inflammatory bowel disease was 59%, 89%, 8.1, respectively. Clinical variables significantly associated with anti-Saccharomyces cerevisiae antibody status in logistic regression were found to be ileal location (p =0.01) and earlier age at diagnosis (p<0.01). Among ileal Crohn's disease patients, there was a trend in concordance between anti-Saccharomyces cerevisiae antibody titres and higher number of surgical procedures which was not statistically significant applying more complex statistics.Conclusions. In an Italian inflammatory bowel disease population, anti-Saccharomyces cerevisiae antibodies status showed characteristics similar to those previously reported. Anti-Saccharomyces cerevisiae antibody positivity is associated with ileal involvement and with earlier onset of Crohn's disease.     

Ortho-quinones of benzene and estrogens induce hyperproliferation of human peripheral blood mononuclear cells

Benzene is a known leukemogen. It has been hypothesized that benzene and natural estrogens initiate cancer by forming ortho-quinones (catechol quinones) that react with DNA in cells. These quinones form depurinating DNA adducts that generate the mutations leading to cancer. This study examined whether the treatment of normal human peripheral blood mononuclear cells with the ortho-quinones of benzene or estradiol would form DNA adducts and elicit an alteration in the proliferation of these cells. Both estradiol-3,4-quinone and benzene ortho-quinone formed depurinating DNA adducts and significantly increased the mitogen-induced proliferation of normal blood mononuclear cells. Immunophenotyping of the estradiol-3,4-quinone-treated blood cells indicated that monocyte/macrophage, natural killer and T-cells were particularly prone to hyperproliferation. Thus, DNA damage induced by the ortho-quinones of benzene and estradiol may promote the growth of human blood mononuclear cells, including those that appear in large numbers in leukemia and lymphoma.     

Myc down-regulation sensitizes melanoma cells to radiotherapy by inhibiting MLH1 and MSH2 mismatch repair proteins.

PURPOSE: Melanoma patients have a very poor prognosis with a response rate of <1% due to advanced diagnosis. This type of tumor is particularly resistant to conventional chemotherapy and radiotherapy, and the surgery remains the principal treatment for patients with localized melanoma. For this reason, there is particular interest in the melanoma biological therapy. EXPERIMENTAL DESIGN: Using two p53 mutant melanoma models stably expressing an inducible c-myc antisense RNA, we have investigated whether Myc protein down-regulation could render melanoma cells more susceptible to radiotherapy, reestablishing apoptotic p53-independent pathway. In addition to address the role of p53 in the activation of apoptosis, we studied the effect of Myc down-regulation on radiotherapy sensitivity also in a p53 wild-type melanoma cell line. RESULTS: Myc down-regulation is able per se to induce apoptosis in a fraction of the cell population (approximately 40% at 72 hours) and in combination with gamma radiation efficiently enhances the death process. In fact, approximately 80% of apoptotic cells are evident in Myc down-regulated cells exposed to gamma radiation for 72 hours compared with approximately 13% observed after only gamma radiation treatment. Consistent with the enhanced apoptosis is the inhibition of the MLH1 and MSH2 mismatch repair proteins, which, preventing the correction of ionizing radiation mismatches occurring during DNA replication, renders the cells more prone to radiation-induced apoptosis. CONCLUSIONS: Data herein reported show that Myc down-regulation lowers the apoptotic threshold in melanoma cells by inhibiting MLH1 and MSH2 proteins, thus increasing cell sensitivity to gamma radiation in a p53-independent fashion. Our results indicate the basis for developing new antitumoral therapeutic strategy, improving the management of melanoma patients.     

Surgical wound infection in patients treated with hip arthroplasty

This is an epidemiological non concurrent cohort study on surgical site infections after hip arthroplasties, based on the information contained in 305 records of patients operated at the "Santa Casa de Belo Horizonte" Hospital. The goals were to determine the incidence rates of surgical site infection in patients, aiming at verifying the association between the surgical site infection and some risk factors and at identifying the time for the manifestation of surgical site infection and the microorganisms involved. The prevalent microorganism was the Staphylococcus aureus. A 8.5% accumulated incidence rate of surgical site infection was found. The risks factors associated to infection were patient's clinical condition (ASA); pre and post-operative hospitalization time; type of surgical procedure; anesthesia and hospitalization unit.