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Biomedical subjects

R Esposito

Publications and source records attributed to R Esposito.

At least 19 recordsLinked to original sources
PubMed2006

Posttransplant Mycobacterium tuberculosis disease following liver transplantation and the need for cautious evaluation of Quantiferon TB GOLD results in the transplant setting: a case report.

This report describes a case of pulmonary tuberculosis in a liver transplant patient without a history of previous exposure to Mycobacterium tuberculosis (MTB) complex. Prior to transplantation, the tuberculin skin test was negative and the QuantiFERON-TB Gold (QFT Gold), an interferon gamma-based blood test, was negative before and after transplant including a period beginning on postoperative day 55 when the patient developed a febrile illness with an interstitial infiltrate and pleural effusion that was unresponsive to broad-spectrum antibiotic therapy. Empiric treatment with isoniazid, ethambutol, and levofloxacin resulted in resolution of the clinical symptoms. A sputum culture grew MTB on postoperative day 87. This case illustrates the need for caution when QFT Gold is used as diagnostic tool for latent tuberculosis during the pretransplant assessment. Further studies evaluating the usefulness of QFT Gold and other interferon gamma tests in posttransplantation active infection are warranted.

Adult↗
PubMed2006

Pharmacokinetic interaction between Amprenavir/Ritonavir and FosAmprenavir on cyclosporine in two patients with human immunodeficiency virus infection undergoing orthotopic liver transplantation.

The pharmacokinetic interaction between highly active antiretroviral therapy (HAART) and immunosuppressive drugs is a critical element in the management of patients with human immunodeficiency virus infection who undergo orthotopic liver transplantation (OLT). We describe the effect of the coadministration of Amprenavir/Ritonavir (APV/r) and FosAmprenavir (FosAPV) on cyclosporine (CsA) concentrations in two patients receiving OLT for end-stage liver disease due to hepatitis C Virus. Patient 1, who was maintained on 300 mg CsA twice a day with a trough concentration (C(trough)) around 250 ng/mL, restarted HAART 12 days after transplantation with 300 mg APV/r twice a day with corresponding APV C(trough) of 5293 ng/mL and RTV C(trough) of 186 ng/mL. Forty-eight hours after initiation of HAART, C(trough) of CsA was 1200 mg/mL, so it was necessary to reduce the CsA dosage 12-fold (50 mg every day) to achieve a therapeutic effect. In Patient 2, who was maintained on 300 mg CsA twice a day and a corresponding C(trough) of 400 ng/mL, HAART was restarted 12 days post-OLT with FosAPV 1400 mg twice a day. After 48 hours C(trough) of CsA was around 600 ng/mL and C(trough) of FosAPV, 1221 ng/mL. In this case it was necessary to reduce the CsA administration 3.5-fold (175 mg every day). In conclusion, therapeutic drug monitoring was necessary to monitor HAART and CsA post-OLT to prevent toxicity due to both therapies. The use of FosAPV without ritonavir boostering is sufficient to maintain adequate CsA blood concentrations, avoiding any event of toxicity.

Adult↗
PubMed2006

Epidemiology of candidaemia and antifungal susceptibility patterns in an Italian tertiary-care hospital.

The epidemiological and antifungal susceptibility data for 94 episodes of candidaemia in an Italian tertiary-care hospital between January 2000 and August 2003 were evaluated by prospective laboratory-based surveillance. The incidence of fungaemia was 0.90 episodes/10 000 patient-days, and the most common species isolated were Candida albicans (40.4%), Candida parapsilosis (22.3%), Candida tropicalis (16.0%) and Candida glabrata (12.8%). Among 24 patients who received antifungal prophylaxis, non-albicans Candida spp. were more prevalent than C. albicans (p 0.012). The 30-day mortality rate was high (38.2%), particularly for haematological (71.4%) and solid-organ transplant patients (50.0%), and in individuals with C. tropicalis and C. glabrata bloodstream infections (60.0% and 50.0%, respectively). In-vitro susceptibility tests demonstrated that 95% of the isolates were susceptible to amphotericin B (MIC < 2 mg/L), 98.1% to posaconazole (MIC < 1 mg/L), 95.8% to flucytosine (MIC < 32 mg/L) and fluconazole (MIC < 64 mg/L), and 94.7% to itraconazole (MIC < 1 mg/L). Posaconazole was active (MIC 0.5 mg/L) against all three isolates of Candida krusei, which had reduced susceptibility to both fluconazole and itraconazole. Overall, non-albicans Candida spp. accounted for 60% of the episodes of candidaemia, which could be related to the use of antifungal prophylaxis. Resistance is still uncommon in Candida spp. recovered from blood cultures. The in-vitro activity of posaconazole is encouraging, and this agent could play an important role in the management of invasive candidiasis, including episodes caused by inherently less susceptible species such as C. krusei.

Adolescent↗
PubMed2005

Fatal cytomegalovirus necrotising enteritis in a small bowel transplantation adult recipient with low pp65 antigenaemia levels.

Although advances in immunosuppressive therapy have led to increased survival of solid organ transplantation recipients, it is well established that current protocols have been associated with an increased risk of developing tissue-invasive infections. In particular, cytomegalovirus still represents an important cause of morbidity. We report a case of cytomegalovirus infection involving the graft ileum with documented necrotising enteritis that developed after small bowel transplantation. The patient, a 56-year-old Caucasian female with a postsurgery short bowel syndrome, underwent a small bowel transplantation. Immunosuppression was maintained by combination of tacrolimus, steroids and daclizumab. Both the donor and the recipient were serologically negative for cytomegalovirus IgG. Nevertheless, ganciclovir prophylaxis was given for 21 days after surgery, as standard procedure. On hospital day 174, routine pp65 antigenaemia resulted positive (14/200,000 peripheral blood leukocytes). The patient was asymptomatic and preemptive ganciclovir therapy was instituted. In the following 3 days, due to a cytomegalovirus antigenaemia increase, ganciclovir was changed to foscarnet with subsequent virological response (7/200,000 peripheral blood leukocytes, on day 181). Two days later, the patient complained of acute abdominal pain and she underwent surgery for the diagnosis. Since the intraoperative findings consisted of a diffuse acute purulent peritonitis, the intestinal graft, together with native rectum, was removed. Biopsy specimens showed evidence of tissue-invasive cytomegalovirus infection. Postsurgery, the patient developed septic shock and died on day 198 as a consequence of multiple organ failure.

Aged↗
PubMed2005

An experimental and theoretical composite model of the human mandible.

The purpose is to design and manufacture a composite mandible replicate suitable for testing the influence of prosthetic materials on the stress distribution of bone. Composite mandibles made of a poly(methylmethacrylate) core and a glass reinforced outer shell are manufactured and characterised through mechanical tests assisted by the finite element analysis. The mandible replicate has been conveniently equipped with strain gauges, moreover a video extensometer has also been used in order to measure the arch width change during loading. A close agreement is found between the experimental data and the theoretical predictions. By laterally loading the mandibles the maximum values of stress and strain take place in the premolar-incisal region. By varying technological parameters such as the fiber volume fraction and orientation, it is easy to replicate the behaviour of mandibles having different stiffnesses. The results obtained by laterally loading the composite mandibles through the condyles or through the gonion regions are consistent with literature data relative to the arch width decrease of natural jaws during opening and closing. This novel synthetic system coupled with the Finite Element model constitutes an experimental-theoretical model suitable to investigate the biomechanical effects of oral rehabilitations on mandibular bone.

Humans↗
PubMed2004

Time-resolved contrast function and optical characterization of spatially varying absorptive inclusions at different depths in diffusing media.

The role of a spatially varying absorptive inhomogeneity located at different depths within a turbid material has been investigated. This inhomogeneity has been characterized by a spatially dependent Gaussian distribution of its absorption coefficient. The present study has been performed calculating the time-resolved contrast function in the framework of the first-order perturbative approach to the diffusion equation for a slab geometry and a coaxial measurement scheme. The model has allowed us to take into account different locations of the inclusion along the source-detector axis. The accuracy of time-resolved contrast predictions has been analyzed through comparisons with results of the finite element method that has been used to numerically solve the diffusion equation. Recovery of the absorption perturbation parameter of the inhomogeneity for different axial positions has also been investigated.

Computer Simulation↗
PubMed2004

Outcome, incidence, and timing of infections in small bowel/multivisceral transplantation.

The objective of this study was to assess the timing, incidence, and outcome of infections in patients with small bowel/multivisceral transplants (SB/MV Tx). A 180-day follow-up was obtained on 13 SB/MV patients transplanted from January 2001 to June 2002. Fifty-six documented infections were observed. By Kaplan-Meier analysis for time to infection, most of which were of bacterial origin (more than 86%), revealed most events to have occurred within the first month post-Tx. Viral infections were equally distributed after the 30th postoperative day.

Adult↗
PubMed2004

Microgravity effect on testicular functions.

In mammals spaceflight influences spermatogenesis since spermatogonial germ cell proliferation, compared to synchronous controls, is lightly decreased in irradiated or flown rats. Moreover, changes of the plasmatic testosterone production was described either in flight rats, or in rats maintained in simulated microgravity conditions. The hormonal levels of the astronauts change as it has been previously described, including hormones involved in the regulation of spermatogenesis such as testosterone and luteinizing hormone (LH). In microgravity conditions, human testosterone levels decreased whereas circulating LH levels increased. To study the effect of simulated microgravity on mammalian spermatogenesis we have utilized the Rotary Cell Culture System (RCCS) and we have cultured testicular fragments isolated from prepuberal rats in a chemically defined medium for three days under microgravity conditions. As control we have cultured the same amount of fragments at unit gravity. The morphology of the samples has been studied and the number of proliferating cells has been counted in control samples and in samples maintained in RCCS. The results indicate that the number of duplicating cells in the tubules was significantly increased in the microgravity-cultured fragments. The amount of testosterone secreted in the culture medium has been also evaluated and in RCCS samples the amount of the hormone was higher respect to the control samples.

Animals↗
PubMed2003

Perturbation model to predict the effect of spatially varying absorptive inhomogeneities in diffusing media.

We develop a perturbation model to predict the effect of a spatially varying absorptive inhomogeneities in a diffusing slab. The model is based on a perturbation solution of diffusion equation derived for a refractive index mismatch between the scattering slab and the surrounding medium, through the use of the extrapolated boundary conditions. We show that the model allows to compute the time-dependent relative change in the transmitted signal resulting from the presence of the inclusion. We derive simplified expressions for the perturbed time-resolved transmittance that allows to implement an efficient fitting procedure for obtaining the optical properties of the absorptive inclusion. The accuracy of the predictions of the model was investigated through comparison with the results of the Finite Element Method to solve the time-dependent diffusion equation numerically. The procedure is used to obtain the absorption perturbation parameter of an absorptive inclusion characterized by spatially dependent Gaussian distribution of its absorption coefficient located at the midplane of a scattering slab.

Journal Article↗
PubMed2001

Percutaneous coronary intervention versus coronary artery bypass graft surgery for patients with medically refractory myocardial ischemia and risk factors for adverse outcomes with bypass: a multicenter, randomized trial. Investigators of the Department of Veterans Affairs Cooperative Study #385, the Angina With Extremely Serious Operative Mortality Evaluation (AWESOME).

BACKGROUND: Percutaneous coronary intervention (PCI) and coronary artery bypass graft surgery (CABG) are being applied to high-risk populations, but previous randomized trials comparing revascularization methods have excluded a number of important high-risk groups. OBJECTIVES: This five-year, multicenter, randomized clinical trial was designed to compare long-term survival among patients with medically refractory myocardial ischemia and a high risk of adverse outcomes assigned to either a CABG or a PCI strategy, which could include stents. METHODS: Patients from 16 Veterans Affairs Medical Centers were screened to identify myocardial ischemia refractory to medical management and the presence of one or more risk factors for adverse outcome with CABG, including prior open-heart surgery, age >70 years, left ventricular ejection fraction <0.35, myocardial infarction within seven days or intraaortic balloon pump required. Clinically eligible patients (n = 2,431) underwent coronary angiography; 781 were angiographically acceptable; 454 (58% of eligible) patients consented to random assignment between CABG and PCI. RESULTS: A total of 232 patients was randomized to CABG and 222 to PCI. The 30-day survivals for CABG and PCI were 95% and 97%, respectively. Survival rates for CABG and PCI were 90% versus 94% at six months and 79% versus 80% at 36 months (log-rank test, p = 0.46). CONCLUSIONS: Percutaneous coronary intervention is an alternative to CABG for patients with medically refractory myocardial ischemia and a high risk of adverse outcomes with CABG.

Aged↗
PubMed2001

Coadministration of losartan and enalapril exerts additive antiproteinuric effect in IgA nephropathy.

Angiotensin-converting enzyme (ACE) inhibitors and AT1-receptor antagonists (ARAs) are widely administered to reduce urinary protein loss and slow the progression of proteinuric nephropathy to end-stage renal failure. Our group recently observed that the combination of ACE inhibitors and ARAs may have an additive antiproteinuric effect, which may occur because ACE inhibitors do not completely reduce angiotensin II (Ang II) production. Ang II is also produced by chymase. Thus, combination therapy better antagonizes the effects of Ang II. The purpose of this study is to ascertain whether the additive antiproteinuric effect of ACE inhibitors plus ARAs is dose dependent and related to the drug-induced reduction in systemic blood pressure. Therefore, enalapril (E; 10 mg/d) and losartan (LOS; 50 mg/d) were randomly administered alone and then in association; initial dosages were doubled when drugs were administered alone and in association. To determine the influence of the drug-dependent effect on reducing blood pressure and the reduction in urinary proteinuria, both ambulatory and office blood pressures were recorded. E and LOS administered alone reduced proteinuria by the same extent; no further reduction was observed when E and LOS alone were administered at a doubled dose. When E and LOS were coadministered, proteinuria decreased by a greater extent compared with E and LOS alone; an additional reduction in proteinuria was observed when combined therapy doses were doubled. The reduction in proteinuria was not correlated with clinical through blood pressure; however, reductions in diastolic and mean ambulatory blood pressures significantly correlated with the decrease in proteinuria, as well as with creatinine clearance. In conclusion, this study shows that combination therapy with E and LOS has an additive dose-dependent antiproteinuric effect that is likely induced by the drug-related reduction in systemic blood pressure. In normotensive proteinuric patients, it is likely that even a small reduction in systemic blood pressure may affect intraglomerular hemodynamics by a great extent because efferent arteriole regulation is hampered more completely by the coadministration of ACE inhibitors and ARAs.

Adult↗
PubMed2001

Minimally invasive versus sternotomy approaches for mitral reconstruction: comparison of intermediate-term results.

BACKGROUND: This study compares intermediate-term outcomes of mitral valve reconstruction after either the standard sternotomy approach or the new minimally invasive approach. Although minimally invasive mitral valve operations appear to offer certain advantages, such as reduced postoperative discomfort and decreased postoperative recovery time, the intermediate-term functional and echocardiographic efficacy has not yet been documented. METHODS: From May 1996 to February 1999, 100 consecutive patients underwent primary mitral reconstruction through a minimally invasive right anterior thoracotomy and peripheral cardiopulmonary bypass and Port-Access technology (Heartport, Inc, Redwood City, Calif). Outcomes were compared with those for our previous 100 patients undergoing primary mitral repair who were operated on with the standard sternotomy approach. RESULTS: Although patients were similar in age, the patients undergoing the minimally invasive approach had a lower preoperative New York Heart Association classification (2.1 +/- 0.5 vs 2.6 +/- 0.6, P <.001). There was one (1.0%) hospital mortality with the sternotomy approach and no such case with the minimally invasive approach. Follow-up revealed that residual mitral insufficiency was similar between the minimally invasive and sternotomy approaches (0.79 +/- 0.06 vs 0.77 +/- 0.06, P =.89, 0- to 3-point scale); likewise, the cumulative freedom from reoperation was not significantly different (94.4% vs 96.8%, P =.38). Follow-up New York Heart Association functional class was significantly better in the patients undergoing the minimally invasive approach (1.5 +/- 0.05 vs 1.2 +/- 0.05, P <.01). CONCLUSIONS: These findings demonstrate comparable 1-year follow-up results after minimally invasive mitral valve reconstruction. Both echocardiographic results and New York Heart Association functional improvements were compatible with results achieved with the standard sternotomy approach. The minimally invasive approach for mitral valve reconstruction provides equally durable results with marked advantages for the patient and should be more widely adopted.

Cardiopulmonary Bypass↗
PubMed2001

Depth dependence of the analytical expression for the width of the point spread function (spatial resolution) in time-resolved transillumination.

Simple analytical expressions for the point spread function (PSF) at different depths can save computation time and improve the performance of inverse algorithms for optical imaging. In particular, application of such formulas simplifies quantification of the optical characteristics of tissue abnormalities inside highly scattering media. Earlier it was shown within the random walk theory framework that the PSF for time-resolved transillumination imaging through a highly scattering slab is well represented by a Gaussian. We have experimentally validated a simple formula of the random walk model for the effective width of this Gaussian, as a function of time delay, at different depths of the target. Presented analysis of published experimental data, concerning effective width of the PSF, for a slab of considerably smaller thickness also demonstrates good agreement between the data and predictions of our model. This PSF width determines spatial resolution of the time-resolved imaging and is widely discussed in the literature.

Diagnostic Imaging↗
PubMed2000

Discontinuation of primary prophylaxis for Pneumocystis carinii pneumonia and toxoplasmic encephalitis in human immunodeficiency virus type I-infected patients: the changes in opportunistic prophylaxis study.

A multicenter open, randomized, controlled trial was conducted to determine whether primary prophylaxis for Pneumocystis carinii pneumonia and toxoplasmic encephalitis can be discontinued in patients infected with human immunodeficiency virus type 1 (HIV-1) whose CD4+ T cell counts have increased to >200 cells/mm3 (and who have remained at this level for at least 3 months) as a result of highly active antiretroviral therapy (HAART). Patients were randomized to either the discontinuation arm (i.e., those who discontinued prophylaxis; n=355) or to the continuation arm (n=353); the 2 arms of the study were similar in terms of demographic, clinical, and immunovirologic characteristics. During the median follow-ups of 6.4 months (discontinuation arm) and 6.1 months (continuation arm) and with a total of 419 patient-years, no patient developed P. carinii pneumonia or toxoplasmic encephalitis. The results of this study strongly indicate that primary prophylaxis for P. carinii pneumonia and toxoplasmic encephalitis can be safely discontinued in patients whose CD4+ T cell counts increase to >200 cells/mm3 during HAART.

AIDS-Related Opportunistic Infections↗