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Biomedical subjects

R Murri

Publications and source records attributed to R Murri.

At least 19 recordsLinked to original sources
PubMed2000

Strain-driven morphology of Si1-xGex islands grown on Si(100)

A study has been carried out on the morphology and structure of three-dimensional (3D) SiGe islands grown by molecular beam epitaxy (MBE) on Si(100) substrates. Samples of Si1-xGex alloys have been prepared to investigate the effects either of the alloy composition or of the growth temperature. Atomic force microscopy (AFM) evidenced the growth of 3D islands and transmission electron microscopy (TEM) demonstrated wetting layer growth on Si(100), independently on the deposition conditions. Energy dispersive spectroscopy (EDS) micro-analyses carried out on cross-sections of large Si1-xGex islands with defects allowed a measurement of the Ge distribution in the islands. To the best of our knowledge, these have been the first experimental evidences of a composition change inside SiGe islands. The interpretation of the experimental results has been done in terms of strain-enhanced diffusion mechanisms both of the growing species (Si and Ge) and of small islands.

Journal Article↗
PubMed1999

Clinical and virological monitoring during treatment with intrathecal cytarabine in patients with AIDS-associated progressive multifocal leukoencephalopathy.

We describe the clinical and virological outcome of human immunodeficiency virus-infected patients with progressive multifocal leukoencephalopathy (PML) treated with cytarabine. Twenty-seven patients received intrathecal cytarabine, 5 received concomitant intravenous cytarabine, and 20 received concomitant antiretroviral therapy. The median baseline CD4+ cell count was 28/mm3. After 4 weeks, 4 (19%) of 21 evaluable patients had stable disease, whereas the others progressed. The median survival from diagnosis and from onset was 66 and 128 days, respectively. Patients with Karnofsky scores of >50 and those previously taking antiretroviral medications had a higher probability of survival 3 months after diagnosis (P = .003 and P = .05, respectively). Overall, after 4 weeks, median JC virus load in CSF increased by 0.7 log10 copies/mL from baseline (P = NS). The mean JC virus load at 4 weeks was lower in patients with stable disease than in progressors (3.47 vs. 4.47 log10 copies/mL; P = .027). JC virus became undetectable in the only patient who had a long-term stable condition. The concentration of JC virus in CSF showed a correlation with clinical outcome.

AIDS-Related Opportunistic Infections↗
PubMed1999

Value of combined approach with thallium-201 single-photon emission computed tomography and Epstein-Barr virus DNA polymerase chain reaction in CSF for the diagnosis of AIDS-related primary CNS lymphoma.

PURPOSE: To determine the diagnostic capability of thallium-201 (201Tl) single-photon emission computed tomography (SPECT) combined with Epstein-Barr virus DNA (EBV-DNA) in CSF for the diagnosis of AIDS-related primary CNS lymphoma (PCNSL). PATIENTS AND METHODS: All human immunodeficiency virus (HIV)-infected patients with focal brain lesions observed between June 1996 and March 1998 underwent lumbar puncture and 201Tl SPECT. Each CSF sample was tested with polymerase chain reaction (PCR) for EBV-DNA. RESULTS: Thirty-one patients were included, 13 with PCNSL and 18 with nontumor disorders. In 11 PCNSL patients, EBV-DNA was positive. Thallium-201 uptake ranged from 1.90 to 4.07 in PCNSL cases (mean, 2.77; 95% confidence interval [CI], 2.35 to 3.19) and from 0.91 to 3.38 in nontumor patients (mean, 1.62; 95% CI, 1.30 to 1.94) (P<.0002). Using a lesion/background ratio of 1.95 as cutoff, a negative SPECT was found in one PCNSL case and 16 nonneoplastic cases. A cryptococcoma and a tuberculoma showed highly increased 201Tl uptake. Epstein-Barr virus DNA was never detected in nonneoplastic patients. For PCNSL diagnosis, hyperactive lesions showed 92% sensitivity and 94% negative predictive value (NPV), whereas positive EBV-DNA had 100% specificity and 100% positive predictive value. The presence of increased uptake and/or positive EBV-DNA had 100% sensitivity and 100% NPV. CONCLUSION: Combined SPECT and EBV-DNA showed a very high diagnostic accuracy for AIDS-related PCNSL. Because PCNSL likelihood is extremely high in patients with hyperactive lesions and positive EBV-DNA, brain biopsy could be avoided, and patients could promptly undergo radiotherapy or multimodal therapy. On the contrary, in patients showing hypoactive lesions with negative EBV-DNA, empiric anti-Toxoplasma therapy is indicated. In patients with discordant SPECT/PCR results, brain biopsy seems to be advisable.

Adult↗
PubMed1998

Changing disease patterns in focal brain lesion-causing disorders in AIDS.

OBJECTIVES: To assess temporal trends of the different disorders causing focal brain lesions (FBL) in HIV-infected patients and to examine the reliability of the U.S. Centers for Disease Control and Prevention (CDC) criteria for presumptive diagnosis of toxoplasmic encephalitis (TE) for the years 1991 to 1996. DESIGN/METHODS: A prospective, monocenter study. Percentages of occurrence of the different FBL-causing disorders for each year were calculated. Temporal trends were analyzed by chi2 test for linear trend and multivariate polytomous nonordinal logistic regression. The positive predictive value (PPV) of the CDC's presumptive criteria for the diagnosis of TE (recent onset of a focal neurologic abnormality consistent in intracranial disease or a reduced level of consciousness, evidence on brain imaging of a lesion having mass effect or the radiographic appearance of which is enhanced by injection of contrast medium, and serum antibody to toxoplasmosis) was calculated using contingency tables for each calendar year. RESULTS: A highly significant decline of the risk of TE and an increase of the probability of patients to take anti-Toxoplasma prophylaxis were observed. A threefold but statistically not significant augmented risk of diagnosing both primary central nervous system lymphoma (PCNSL) and progressive multifocal leucoencephalopathy (PML) has been registered for 1996 compared with 1991. Among FBL showing contrast enhancement, the increased finding of PCNSL over the years studied was significant. The probability of other FBL-causing disorders, such as focal viral encephalitis sustained by cytomegalovirus or herpes simplex virus, increased significantly over the years studied. Multivariate analysis confirmed that the year of diagnosis of FBL had a significant effect on the risk reduction of TE. The PPV of the CDC's criteria for the presumptive diagnosis of TE dropped from 100% for the year 1991 to 39% in the year 1996. A similar result was obtained in calculating the PPV of presumptive criteria only among patients without previous primary prophylaxis. CONCLUSIONS: Because of the significant decrease of TE and the increase of PCNSL empiric anti-Toxoplasma therapy no longer seems appropriate as a first-line approach to all HIV-positive patients with FBL. Especially in the case of a finding of FBL by contrast enhancement, new diagnostic strategies should be employed to identify the underlying disorder rapidly and accurately.

Acquired Immunodeficiency Syndrome↗
PubMed1998

Many factors can affect the prevalence of hypertension in obese patients: role of cuff size and type of obesity.

OBJECTIVE: To determine to what extent methodological errors, including measurements taken with inappropriate cuffs and/or inaccuracies in patient enrollment, can contribute to overestimating the prevalence of hypertension in overweight or obese women. EXPERIMENTAL DESIGN: Randomized and comparative investigation in overweight or obese outpatient women of the Obesity Clinic, Internal Medicine Institute, Chieti University. PATIENTS: In 1,791 overweight or obese women, randomly selected and stratified by age (41-60 years), blood pressure (BP) was taken with casual measurement in the morning. The entire study group was divided into two subgroups. In the first one, causal BP was measured with a standard-size cuff (RCS), while an appropriate large-size cuff was used for the second one (LCS). Patients of the latter subgroup were also divided by type of obesity (android and gynoid), based on their waist-to-hip ratio. RESULTS: In the LCS subgroup, the hypertension prevalence rate was strikingly lower among overweight and obese women, as well as in the younger and older age groups, when compared with the corresponding RCS subgroups (p < 0.001). The hypertension prevalence rate was higher for all android obese subjects (53%), including younger (34%) and older (64%) groups, when compared with gynoid obese patients (29%, 18% and 42%, respectively). CONCLUSIONS: A comparison of different reports on the prevalence of hypertension in obesity reveals considerable differences, due mainly to age, sex, race and income level. Nevertheless, our data seem to indicate that even after adjusting for the above-mentioned variables, two significant confounding factors, cuff hypertension and the prevalence of android obesity in the obese study population, could be responsible for over-estimating the prevalence of hypertension. It should be noted that for certain groups of overweight and obese women, the prevalence of hypertension becomes similar to the rate found among the general population, as reported in many large epidemiological surveys.

Adult↗
PubMed1997

Disease-related factors associated with health-related quality of life in people with nonadvanced HIV disease assessed using an Italian version of the MOS-HIV Health Survey.

OBJECTIVE: This study was intended to present evidence for the reliability and validity of an Italian version of the MOS-HIV Health Survey and to identify important disease-related factors associated with health-related quality of life (HRQoL) in people with nonadvanced HIV. DESIGN: In this cross-sectional study, HRQoL was measured using an Italian version of the MOS-HIV Health Survey questionnaire in 213 HIV-infected people without previous opportunistic infections or neoplasms attending an outpatient clinic in a university hospital. Distribution of scores, reliability, and validity were calculated, and presence and frequency of HIV-related symptoms were recorded and transformed into a score. The relation of HRQoL values to sociodemographic, epidemiologic, and clinical data was assessed. RESULTS: The level of internal consistency of the Italian version of the MOS-HIV Health Survey was high (Cronbach's alpha, 0.80-0.93), and items demonstrated acceptable discrimination across scales. At linear regression analysis, all domains of HRQoL correlated with symptom score (r2 range, 0.07-0.41), but only the pain and physical-functioning scores showed a significant correlation with CD4 cell count. A weighted sum of single domains of HRQoL, TOTQoL, is also strongly correlated with symptom score (r2 = 0.57; p < .0001) but not with CD4 cell count (r2 = 0.01; p = .1). Using multivariate analysis, only symptom score (p < .0001) and total number of daily pills (p = .03) showed significant association with HRQoL. The same results were observed when analysis was performed only on people with CD4 levels <200/microl. CONCLUSIONS: This study presents the first evidence for the reliability and validity of a HRQoL instrument in Italian for people with HIV. Results also suggest a strong impact of symptoms on all measured dimensions of health status. The number of pills required to be taken daily is the only other significant factor associated with a lower HRQoL, whereas no relations were found with CD4 cell count or Karnofsky performance status values. To improve HRQoL in persons with nonadvanced HIV disease, symptom control could be a crucial element of medical treatment.

Adult↗
PubMed1997

Diagnosis of AIDS-related focal brain lesions: a decision-making analysis based on clinical and neuroradiologic characteristics combined with polymerase chain reaction assays in CSF.

OBJECTIVE: To identify disease patterns in AIDS-related focal brain lesions (FBL) and to design a decision-making strategy for differential diagnosis. DESIGN: Prospective study. Probabilities of CNS disorders were calculated using Bayes' theorem according to clinical variables (mass effect at CT or MRI, Toxoplasma serology, anti-Toxoplasma prophylaxis) and to the results of polymerase chain reaction (PCR) assays. PATIENTS: 136 consecutive HIV-infected patients with a definitive diagnosis of FBL-causing disorder observed from 1991 to 1995 in a single clinical setting. INTERVENTIONS: Patients underwent empiric anti-Toxoplasma therapy. After 3 weeks, patients with progressive/stable disease underwent brain biopsy. In 66 patients Epstein-Barr virus (EBV)-DNA, JC virus (JCV)-DNA, and T gondii-DNA amplification was performed by PCR in CSF. Diagnostic criteria were histopathologic examination of bioptic or autoptic tissue specimens for all disorders and complete/partial resolution of FBL after empiric therapy for toxoplasmic encephalitis (TE). RESULTS: Neuroradiologic characteristics did not discriminate between TE and primary CNS lymphoma (PCNSL). Probability of TE was 0.87 in Toxoplasma-seropositive patients with mass effect who were not receiving anti-Toxoplasma prophylaxis, but only 0.59 if prophylaxis was performed. In seronegative patients with mass effect, the likelihood of PCNSL was 0.74. If EBV-DNA or T gondii-DNA tests were positive, the probability of PCNSL or TE increased to more than 0.96. The absence of T gondii-DNA did not exclude the possibility of a TE diagnosis. Among FBL without mass effect, the probability of progressive multifocal leukoencephalopathy (PML) was 0.81; this increased to 0.99 if JCV-DNA testing was positive. Sensitivity of brain biopsy was 93%, with a perioperative morbidity of 12% and a mortality of 2%. CONCLUSIONS: Due to the low diagnostic capability of clinical variables, PCR amplifications in CSF, especially for EBV-DNA and for JCV-DNA, represent, in most cases, an essential step in the differential diagnosis of AIDS-related FBL. This is particularly true in patients with FBL without mass effect or with mass effect and who are either seronegative or undergoing anti-Toxoplasma prophylaxis. Brain biopsy remains a necessary procedure in EBV-DNA-positive cases and in seronegative patients with FBL displaying a mass effect. Positive JCV-DNA testing may obviate the need for brain biopsy in patients with FBL without mass effect. An advanced diagnostic strategy based on combined clinical criteria and PCR tests may allow rapid and accurate identification of patients for prompt brain biopsy or specific therapy.

AIDS Dementia Complex↗
PubMed1996

Imbalance between Pneumocystis carinii cysts and trophozoites in bronchoalveolar lavage fluid from patients with pneumocystosis receiving prophylaxis.

Detection and quantification of different Pneumocystis carinii (PC) life cycle forms were performed by polymerase chain reaction (PCR) and by morphological stains on bronchoalveolar lavage fluids (BALF) from HIV-infected patients with P. carinii pneumonia (PCP). The number of PC trophozoites was higher in patients with PCP who were receiving prophylaxis than in those not receiving prophylaxis. Also the cyst: trophozoite ratio was lower in the first group. No difference was observed between patients receiving different prophylactic medications. The imbalance between PC forms in BALF from patients with PCP receiving anti-PC prophylaxis may hamper the sensitivity of cyst stains. Multiple stains or PCR examination should be performed on BALF from patients with clinically suspected PCP who are receiving prophylaxis.

AIDS-Related Opportunistic Infections↗
PubMed1996

PCR detection of Toxoplasma gondii DNA in CSF for the differential diagnosis of AIDS-related focal brain lesions.

To evaluate whether the detection of Toxoplasma gondii DNA in CSF could contribute to the differential diagnosis of AIDS-related focal brain lesions, CSF samples from 88 HIV-infected patients (56 with focal brain lesions and 32 without) were tested prospectively by a nested PCR for the B1 gene of T. gondii. The assay had a detection limit of 10 trophozoite equivalents. Six of 18 patients with toxoplasmic encephalitis, but none of the 70 patients with other disorders, were PCR-positive (33.3% sensitivity and 100% specificity). Considering only those patients with cerebral toxoplasmosis from whom CSF was collected before or during the first week of antitoxoplasmic therapy, sensitivity rose to 50%. This was higher than the sensitivity in patients whose CSF was collected after the first week of treatment (odds ratio (OR) of 7.0; 95% CI: 0.46-218.2). The administration of antitoxoplasmic prophylaxis did not affect the PCR results. Patients with a poor response to therapy had a higher probability of detectable T. gondii DNA in their CSF (OR of 5.0; 95% CI: 0.37-86.6). All patients with other central nervous system disorders were PCR-negative. Despite the moderate sensitivity, the high specificity and positive predictive value (100%) make this assay a useful tool in the differential diagnosis of AIDS-related focal brain lesions as part of a series of CSF and neuroradiological examinations.

AIDS-Related Opportunistic Infections↗
PubMed1996

Improved detection of JC virus DNA in cerebrospinal fluid for diagnosis of AIDS-related progressive multifocal leukoencephalopathy.

Several methods to increase the sensitivity of JC virus (JCV) DNA detection in cerebrospinal fluid (CSF) for a noninvasive diagnosis of AIDS-related progressive multifocal leukoencephalopathy (PML) were investigated. When CSF collected at clinical presentation was tested, JCV DNA was detected in 8 of 19 patients with PML by standard PCR (sensitivity, 42%; 95% confidence interval [CI], 21 to 66%) and in 14 of 19 by nested PCR (sensitivity, 74% [95% CI, 49 to 90%]; P = 0.014 [McNemar's test]. For multiple serial CSF samples, standard PCR yielded JCV DNA for 11 of 19 PML patients (sensitivity, 58% [95% CI, 34 to 79%]) and nested PCR yielded JCV DNA for 17 of 19 patients (sensitivity, 90% [95% CI, 66 to 98%]; P = 0.014). The majority of the false-negative samples were found to contain PCR inhibitors. Standard PCR did not detect JCV DNA in CSF from any of the 83 AIDS patients with other diagnosis (100% specificity [95% CI, 95 to 100%]); JCV DNA was found in CSF from one control patient by nested PCR (99% specificity [95% CI, 93 to 100%]).

AIDS-Related Opportunistic Infections↗