High-performance Fe(Se,Te) films on chemical CeO2-based buffer layers

The fabrication of a Fe-based coated conductor (CC) becomes possible when Fe(Se,Te) is grown as an epitaxial film on a metallic oriented substrate. Thanks to the material's low structural anisotropy, less strict requirements on the template microstructure allow for the design of a simplified CC architecture with respect to the REBCO multi-layered layout. This design, though, still requires a buffer layer to promote the oriented growth of the superconducting film and avoid diffusion from the metallic template. In this work, Fe(Se,Te) films are grown on chemically-deposited, CeO₂-based buffer layers via pulsed laser deposition, and excellent properties are obtained when a Fe(Se,Te) seed layer is used. Among all the employed characterization techniques, transmission electron microscopy proved essential to determine the actual effect of the seed layer on the final film properties. Also, systematic investigation of the full current transport properties J(θ, H, T) is carried out: Fe(Se,Te) samples are obtained with sharp superconducting transitions around 16 K and critical current densities exceeding 1 MA cm^-2 at 4.2 K in self-field. The in-field and angular behavior of the sample are in line with data from the literature. These results are the demonstration of the feasibility of a Fe-based CC, with all the relative advantages concerning process simplification and cost reduction.

Spin-Orbit Semimetal SrIrO_{3} in the Two-Dimensional Limit

We investigate the thickness-dependent electronic properties of ultrathin SrIrO_{3} and discover a transition from a semimetallic to a correlated insulating state below 4 unit cells. Low-temperature magnetoconductance measurements show that spin fluctuations in the semimetallic state are significantly enhanced while approaching the transition point. The electronic properties are further studied by scanning tunneling spectroscopy, showing that 4 unit cell SrIrO_{3} is on the verge of a gap opening. Our density functional theory calculations reproduce the critical thickness of the transition and show that the opening of a gap in ultrathin SrIrO_{3} requires antiferromagnetic order.

Side Gate Tunable Josephson Junctions at the LaAlO3/SrTiO3 Interface

Novel physical phenomena arising at the interface of complex oxide heterostructures offer exciting opportunities for the development of future electronic devices. Using the prototypical LaAlO₃/SrTiO₃ interface as a model system, we employ a single-step lithographic process to realize gate-tunable Josephson junctions through a combination of lateral confinement and local side gating. The action of the side gates is found to be comparable to that of a local back gate, constituting a robust and efficient way to control the properties of the interface at the nanoscale. We demonstrate that the side gates enable reliable tuning of both the normal-state resistance and the critical (Josephson) current of the constrictions. The conductance and Josephson current show mesoscopic fluctuations as a function of the applied side gate voltage, and the analysis of their amplitude enables the extraction of the phase coherence and thermal lengths. Finally, we realize a superconducting quantum interference device in which the critical currents of each of the constriction-type Josephson junctions can be controlled independently via the side gates.

Striped nanoscale phase separation at the metal-insulator transition of heteroepitaxial nickelates

Nucleation processes of mixed-phase states are an intrinsic characteristic of first-order phase transitions, typically related to local symmetry breaking. Direct observation of emerging mixed-phase regions in materials showing a first-order metal–insulator transition (MIT) offers unique opportunities to uncover their driving mechanism. Using photoemission electron microscopy, we image the nanoscale formation and growth of insulating domains across the temperature-driven MIT in NdNiO₃ epitaxial thin films. Heteroepitaxy is found to strongly determine the nanoscale nature of the phase transition, inducing preferential formation of striped domains along the terraces of atomically flat stepped surfaces. We show that the distribution of transition temperatures is a local property, set by surface morphology and stable across multiple temperature cycles. Our data provide new insights into the MIT of heteroepitaxial nickelates and point to a rich, nanoscale phenomenology in this strongly correlated material.

Probing the evolution of mixed-phase states in materials offers unique insights into the microscopic mechanism of phase transitions. Here, Mattoni et al. report imaging of nanoscale formation and growth of insulating domains across the metal-insulator transition in NdNiO₃ thin films, uncovering a rich interplay between structural and electronic degrees of freedom.

Prevalence of multidrug-resistant Acinetobacter baumannii and Pseudomonas aeruginosa in an Italian hospital

The severity and extent of disease caused by multidrug-resistant organisms (MDROs) varies by the population(s) affected and the institution(s) at which these organisms are found; therefore, preventing and controlling MDROs are extremely important. A retrospective study of patients who were infected with Acinetobacter baumannii or Pseudomonas aeruginosa was performed at the Spedali Civili Hospital in Brescia, Italy, from 2007 to 2010. A total of 167 (0.52%) A. baumannii isolates and 2797 P. aeruginosa (8.7%) isolates were identified among 31,850 isolates. Amikacin and colistin were the most active agents against A. baumannii strains. Multidrug resistance (MDR) was observed in 57 isolates (54%). Most MDR isolates (42 out of 57, 73%) were resistant to four classes of antibiotics. P. aeruginosa was recovered more frequently from the respiratory tract, followed by the skin/soft tissue, urine and blood. Colistin, amikacin and piperacillin/tazobactam were active against 100%, 86% and 75% of P. aeruginosa isolates, respectively. A total of 20% (n=316) of P. aeruginosa isolates were MDR. In summary, A. baumannii was more rare than P. aeruginosa but was more commonly MDR. Epidemiological data will help to implement better infection control strategies, and developing a local antibiogram database will improve the knowledge of antimicrobial resistance patterns in our region.

Evolution of transmitted HIV-1 drug resistance in HIV-1-infected patients in Italy from 2000 to 2010

Prevalence and predictors of transmitted drug resistance (TDR), defined as the presence of at least one WHO surveillance drug resistance mutation (SDRM), were investigated in antiretroviral-naïve HIV-1-infected patients, with a genotypic resistance test (GRT) performed ≤6 months before starting cART between 2000 and 2010. 3163 HIV-1 sequences were selected (69% subtype B). Overall, the prevalence of TDR was 12% (13.2% subtype B, 9% non-B). TDR significantly declined overall and for the single drug classes. Older age independently predicted increased odds of TDR, whereas a more recent GRT, a higher HIV-RNA and C vs. B subtype predicted lower odds of TDR.

P. aeruginosa bloodstream infections among hematological patients: an old or new question?

Pseudomonas aeruginosa is a well-known cause of severe and potentially life-threatening infections among hematological patients. A prospective epidemiological surveillance program ongoing at our Hematology Unit revealed an increase over time of P. aeruginosa bloodstream infections (BSI). Their impact on outcome and antibiotic susceptibility was analyzed. BSI which consecutively occurred at our institution during a 70-month period were evaluated and correlated with type of pathogen, status of underlying disease, neutropenia, previous antibiotic therapy, resistance to antibiotics, and outcome. During the observation period, 441 BSI were recorded. Frequency of Gram-negative BSI was higher than that of other pathogens (57.3%). Overall, 66 P. aeruginosa BSI were recorded; 22 out of 66 were multiresistant (MR P. aeruginosa). Thirty-day mortality for all BSI was 11.3%; it was 27.3% for P. aeruginosa BSI and 36.4% for MR P. aeruginosa. At multivariate analysis, only active hematological disease and P. aeruginosa BSI were associated to an increased risk of death. For MR P. aeruginosa, BSI mortality was 83.3% vs. 18.8% when empiric therapy included or not an antibiotic with in vitro activity against P. aeruginosa (p=0.011). Together with active disease, the emergence of P. aeruginosa BSI, particularly if multiresistant, was responsible for an increased risk of death among hematological patients at our institution. In this scenario, reconsidering the type of combination antibiotic therapy to be used as empiric treatment of neutropenic fever was worthwhile.

Zygomycosis in Italy: a survey of FIMUA-ECMM (Federazione Italiana di Micopatologia Umana ed Animale and European Confederation of Medical Mycology)

The aims of the study were to analyze the clinical and epidemiological characteristics and treatments for patients who developed zygomycosis enrolled in Italy during the European Confederation of Medical Mycology of medical mycology survey. This prospective multicenter study was performed between 2004 and 2007 at 49 italian Departments. 60 cases of zygomycosis were enrolled: the median age was 59.5 years (range 1-87), with a prevalence of males (70%). The majority of cases were immunocompromised patients (42 cases, 70%), mainly hematological malignancies (37). Among non-immunocompromised (18 cases, 30%), the main category was represented by patients with penetrating trauma (7/18, 39%). The most common sites of infection were sinus (35%) with/without CNS involvement, lung alone (25%), skin (20%), but in 11 cases (18%) dissemination was observed. According to EORTC criteria, the diagnosis of zygomycosis was proven in 46 patients (77%) and in most of them it was made in vivo (40/46 patients, 87%); in the remaining 14 cases (23%) the diagnosis was probable. 51 patients received antifungal therapy and in 30 of them surgical debridement was also performed. The most commonly used antifungal drug was liposomal amphotericin B (L-AmB), administered in 44 patients: 36 of these patients (82%) responded to therapy. Altogether an attributable mortality rate of 32% (19/60) was registered, which was reduced to 18% in patients treated with L-AmB (8/44). Zygomycosis is a rare and aggressive filamentous fungal infection, still associated with a high mortality rate. This study indicates an inversion of this trend, with a better prognosis and significantly lower mortality than that reported in the literature. It is possible that new extensive, aggressive diagnostic and therapeutic procedures, such as the use of L-AmB and surgery, have improved the prognosis of these patients.

Effectiveness of antiretroviral regimens containing abacavir with tenofovir in treatment-experienced patients: predictors of virological response and drug resistance evolution in a multi-cohort study

BACKGROUND

In treatment-naïve patients, a combination antiretroviral therapy (cART) containing tenofovir (TDF) and abacavir (ABC) with lamivudine leads to unacceptably high virological failure rates with frequent selection of reverse transcriptase mutations M184V and K65R. We explored the efficacy of at least 16 weeks of ABC + TDF-containing cART regimens in 307 antiretroviral-experienced HIV-1-infected individuals included in observational databases.

METHODS

Virological failure was defined as an HIV RNA > 400 copies/ml after at least 16 weeks of treatment. Patients had received a median of three prior cART regimens. Of these, 76% concomitantly received a potent or high genetic barrier regimen (with at least one protease inhibitor [PI]) or non-nucleoside reverse transcriptase inhibitor or thymidine analogue) while a third non-thymidine nucleoside analogue was used in the remaining patients.

RESULTS

The 1-year estimated probability of virological failure was 34% in 165 patients with HIV RNA > 400 copies/ ml at ABC + TDF regimen initiation. Independent predictors of virological failure were the absence of a potent or high genetic barrier cART, the higher number of cART regimens experienced, and the use of a new drug class. In the subset of 136 patients for whom there were genotypic resistance test results prior to ABC + TDF initiation, the virological failure (1-year estimated probability 46%) was independently predicted by the higher baseline viral load, the concomitant use of boosted PI, and the presence of reverse transcriptase mutation M41L. In 142 patients starting ABC + TDF therapy with HIV RNA pound < or =400 copies/ml, virological failure (1-year estimated probability 17%) was associated only with the transmission category. In a small subset of subjects for whom there were an available paired baseline and follow-up genotype (n = 28), the prevalence of most nucleoside analogue reverse transcriptase inhibitor resistance mutations decreased, suggesting a possible low adherence to treatment. No selection of K65R was detected.

CONCLUSION

The virological response to ABC + TDF-containing regimens in this moderately-to-heavily treatment experienced cohort was good. Higher viral load and the presence of M41L at baseline were associated with worse virological responses, while the concomitant prescription of drugs enhancing the genetic barrier of the regimen conveyed a reduced risk of virological failure. The Appendix provides the names of other members of the MASTER cohort.

Different sequence strains of Streptococcus agalactiae elicit various levels of cytokine production

Group B streptococcus (GBS) is the most common cause of neonatal and obstetric sepsis and an increasingly important cause of septicemia in elderly subjects and immunocompromised patients. Our aim was to evaluate whether different genotypes of GBS may induce a different production of pro-inflammatory and anti-inflammatory cytokines. We used multilocus sequence typing to identify 71 clones isolated from asymptomatic healthy carriers and symptomatic individuals. All these clinical isolates were used to infect purified human monocytes. TNF-alpha, IL-6, IL-8 and IL-10 secretion was measured. Fifteen allelic sequence types (STs) were identified. The MLST (multilocus sequence typing) analysis grouped the bacteria into four different lineages (clonal cluster) and two of these were closely involved in the infection of symptomatic subjects: CC17 and CC19. Furthermore, CC17 and CC19 stimulated TNF-alpha, IL-6 and IL-8 production significantly more than the other lineages, while CC17 induced a decreased IL-10 production. These results suggest the existence of differences in immune response to infection with particular genotypes of GBS.

Hyper-reactive malarial splenomegaly in a patient with human immunodeficiency virus

Both hyperreactive malarial splenomegaly (HMS) and HIV infection are highly prevalent in sub-Saharan Africa, but the inter-relationships between the two conditions are not clearly defined. Diagnosis of HMS is particularly difficult in HIV-infected patients, and detection of circulating malaria parasites by polymerase chain reaction (PCR) may represent a useful diagnostic tool.

Comparison of the AMPLICOR Human Papillomavirus Test and the Hybrid Capture 2 Assay for detection of high-risk human papillomavirus in women with abnormal PAP smear

Infection with human papillomavirus (HPV) is a necessary step in the progression to cervical cancer. Many methods for HPV testing are currently available, mostly developed to detect pools of HPV types. Hybrid Capture 2 (HC2) is one of the most widely used. A new PCR-based assay, the Roche AMPLICOR HPV test, has been recently developed. Both assays recognize a group of 13 HR HPV types contemporaneously. This study evaluated the performance of both methods for detecting high-grade cervical lesions as a part of management for abnormal PAP smears. The study population was composed of 213 women, all referred to colposcopy and histologic diagnosis following an abnormal PAP test. Biopsy-confirmed high-grade cervical intraepithelial neoplasia was used as a gold standard. Overall agreement was 84.9% with a kappa value of 0.6. When comparing the ability to detect moderate cervical intraepithelial neoplasia (CIN2+) and high-grade cervical intraepithelial neoplasia (CIN3+/cancer), AMPLICOR proved slightly more sensitive than HC2, a finding that is important when HPV testing is used in a triage of borderline smear results. Genotyping of discordant results showed a prevalence of LR-HPV types in HC2 positive/AMPLICOR negative samples, and a similar prevalence of HR- and LR-HPV types in AMPLICOR positive/HC2 negative samples. In conclusion, the study shows that the AMPLICOR assay is more sensitive than HC2, which makes it a valid alternative for routine clinical use.

Prevalence and distribution of single and multiple HPV infections in cytologically abnormal cervical samples from Italian women

The prevalence of single and multiple HPV infections was assessed over a cohort of 213 women with cytological abnormalities and its association with cervical neoplasia established. Roche linear array HPV genotyping test was used to identify HPV genotypes. The most prevalent HPV genotypes in cervical cancer samples were HPV16 (61.2%), HPV52 (16.1%), HPV18 (12.9%) and HPV 31 (9.6%). Multiple HR and LR HPV infections, comprising between two and 5+ HPV types, were identified in 49.7% of samples, with a significantly lower number in severe dysplasia and cervical cancer samples (p<0.05). These results seem to indicate that detection of multiple HPV infection with HR-HPV types is not significantly better as a predictor of cervical cancer than single HR-HPV infection, though further longitudinal studies are needed to better clarify the relevance of these infections to the progression of cervical neoplasia.

Genetic polymorphisms influence Plasmodium ovale PCR detection accuracy

Detection of Plasmodium ovale by use of a nested PCR assay with a novel Plasmodium ovale primer set was superior to detection of Plasmodium ovale by real-time PCR assays. Nested PCR was also better at detecting P. malariae. The detection of P. ovale in many patients first admitted >2 months following their return to Italy indicated that P. ovale relapses are common.

Human T-cell lymphotropic virus type I (HTLV-I) confirmed by PCR-Southern blot and sequencing analysis in a woman with tropical spastic paraparesis

Human T-cell lymphotropic virus type I (HTLV-I) is a human retrovirus and the aetiological agent of a progressive neurological disease called tropical spastic paraparesis/HTLV-I-associated myelopathy (TSP/HAM), as confirmed by evidence accumulated in HTLV-I seroprevalence studies. TSP/HAM is rarely diagnosed in Italy, given the low prevalence of HTLV-I in the population. TSP/HAM begins insidiously in the fourth decade, mainly with spastic paraparesis of the lower extremities and positive Babinski reflex, as well as interfering with bowel and bladder functions. In this study we report the clinical, virological and haemato chemical data of a 54-year-old woman, born in the Ivory Cost, with symptoms suggestive of TSP. The presence of HTLV-I infection was demonstrated by the detection of antibodies in serum and in cerebrospinal fluid by immunoenzymatic assay and Western blot analysis. In addition, viral isolation was carried out in peripheral blood cells, and the presence of HTLV-I proviral DNA was confirmed by polymerase chain reaction/Southern blot and sequencing analysis. According to our results, HTLV-I testing might be useful when TSP/HAM is suspected.

HIV p17 reverses the anti-inflammatory activity of IL-4 on IL-15 stimulated monocytes and modulates their ability to secrete MIP-1 alpha

Monocytes play a central role in the immune system by producing and reacting to different soluble factors. Cytokine dysregulation is an hallmark in HIV-infected individuals and it is one of the most significant factors leading to impaired immunity in HIV/AIDS disease. This study investigates the possibility of modulation in the secretion of some inflammatory cytokines and chemokines induced by HIV p17 in monocytes. The results show that p17, while ineffective on resting monocytes, exerts an inflammatory action on IL-4 mediated inhibition of TNF-alpha and IFN-gamma production induced by IL-15 stimulation. In addition, p17 is able to reduce MIP-1alpha secretion, but unable to influence IL-6 production. The ability of HIV p17 to contribute to an altered pattern of secreted soluble factors might imply a key role for this viral protein in the development of AIDS pathogenesis.

Early Virological Failure after Tenofovir + Didanosine + Efavirenz Combination in HIV-Positive Patients upon Starting Antiretroviral Therapy

A prospective, randomized pilot trial was conducted in naive patients comparing three different combinations: zidovudine+lamivudine+lopinavir/ritonavir (arm A) versus tenofovir+lamivudine+efavirenz (arm B) versus tenofovir+didanosine+efavirenz (arm C). HIV-RNA slope (days 1, 3, 7, 14 and 28) was slower in arm C with respect to arm B ( P<0.0001). Seven out of eight patients (87.5%) reached undetectable HIV-RNA by week 28 in arm A, 10/10 (100%) in arm B and 6/10 (60%) in arm C. Among arm C patients who failed at week 4, one HIV isolate showed 67N and 219Q, and another one showed 210F and 215D substitutions in the HIV reverse transcriptase gene at baseline, respectively. Non-nucleoside reverse transcriptase inhibitor resistance-related mutations appeared first, followed by 65R mutations in all cases. Efavirenz AUC0–24 values were lower in arm C with respect to arm B, especially in patients who failed early. A high virological failure rate after tenofovir+didanosine+efavirenz correlated with a slower HIV-RNA decrease and a peculiar accumulation of resistance mutations. A constellation of factors could be correlated with early failure events in patients receiving this combination such as resistance mutations or polymorphisms present at baseline, low CD4+ T-cell count or advanced disease and unexpectedly low efavirenz plasma levels.

Detection and genotyping of human papillomavirus in cervical samples from Italian patients

Human papillomaviruses (HPVs) are etiological agents of cervical cancer. In order to assess the epidemiological incidence and frequency of different HPV types, we applied a polymerase chain reaction (PCR)-direct sequencing approach based on the use of MY09/MY11 primers as compared to Hybrid Capture assay. Cervical samples were taken from 1,500 women, both with normal and abnormal cytological smears, and we found an incidence of 6.6% of HPV infection in Brescia. Overall, 97 samples tested HPV-positive, yielding 18 HPV types. The four most frequent HPV types were: HPV 16, -31, -6, and -58. This approach could be used in ordinary laboratory settings for quick and reliable typing of known and novel HPVs from clinical specimens and it could also be applied to anti-cancer vaccine development.

Prevalence of drug resistance and newly recognised treatment-related substitutions in the HIV-1 reverse transcriptase and protease genes from HIV-positive patients naïve for anti-retrovirals

The aim of this study was to assess the prevalence of genetic changes in either the HIV reverse transcriptase (RT) or protease (Pro) genes in a cohort of patients naïve for anti-retroviral therapy. Of 61 patients, 43 (70.5%) were infected with HIV strains harbouring at least one resistance-related mutation, with 41 (67.2%) harbouring newly recognised treatment-related mutations. Among the 61 patients, the prevalence of specific mutations in the RT gene was as follows: 39A, 1.6%; 43E, 1.6%; and 228H, 1.6%. The prevalence of specific mutations in the Pro gene was as follows: 11I, 1.6%; 13V, 26.2%; 35D, 19.6%; 45R, 1.6%; 58E, 1.6%; 62V, 31%; 72V, 11.4%; 72M, 6.5%; 72T, 3.2%; 75I, 1.6%; and 89M, 13%. A higher prevalence of newly recognised mutations was found in strains from patients infected through sexual practices (30/36 = 83.4% vs. 11/25 = 44%; p 0.0023; OR 10.91; 95% CI 3.14-40.39). These findings support the use of resistance testing in patients naïve for anti-retroviral therapy, and suggest that the possible impact of newly recognised treatment-related mutations on clinical outcome requires further investigation.

Polymorphism analysis of Epstein–Barr virus isolates of lymphoblastoid cell lines from patients with mycosis fungoides

In order to determine whether there is an association between the presence of Epstein–Barr virus (EBV) and mycosis fungoides (MF) disease progression, PCR was performed to detect the EBV status of 20 MF patients; six EBV-positive patients were found. EBV variants may differ in their biological properties, such as their ability to transform cells; therefore, the ability of these variants to immortalize B cells in vitro was analysed. Six continuously growing cell lines were obtained from prolonged cultures of unstimulated peripheral blood mononuclear cells that were taken from the six EBV-positive patients with MF. In order to characterize the EBV strains, EBNA-2 and LMP-1/LMP-2 gene polymorphisms in the six cell lines were also analysed. All patients were followed up for 10 years and it was noticed that EBV-positive patients had a poor prognosis with rapid disease progression and high mortality rates, compared to EBV-negative patients. EBV may therefore constitute a co-factor that accelerates the progression of disease.

Development of a real-time PCR assay for detection of Plasmodium falciparum, Plasmodium vivax, and Plasmodium ovale for routine clinical diagnosis

A TaqMan-based real-time PCR qualitative assay for the detection of three species of malaria parasites-Plasmodium falciparum, P. ovale, and P. vivax-was devised and evaluated using 122 whole-blood samples from patients who had traveled to areas where malaria is endemic and who presented with malaria-like symptoms and fever. The assay was compared to conventional microscopy and to an established nested-PCR assay. The specificity of the new assay was confirmed by sequencing the PCR products from all the positive samples and by the lack of cross-reactivity with Toxoplasma gondii and Leishmania infantum DNA. Real-time PCR assay showed a detection limit (analytical sensitivity) of 0.7, 4, and 1.5 parasites/ micro l for P. falciparum, P. vivax, and P. ovale, respectively. Real-time PCR, like nested PCR, brought to light errors in the species identification by microscopic examination and revealed the presence of mixed infections (P. falciparum plus P. ovale). Real-time PCR can yield results within 2 h, does not require post-PCR processing, reduces sample handling, and minimizes the risks of contamination. The assay can therefore be easily implemented in routine diagnostic malaria tests. Future studies are warranted to investigate the clinical value of this technique.

Evaluation of a new plate hybridization assay for the laboratory diagnosis of imported malaria in Italy

A new molecular diagnostic method "Malaria-IBRIDOGEN" (Amplimedical S.p.A.--Bioline Division, Turin, Italy) based on a plate-hybridization assay for the simultaneous detection and identification of human malaria parasites was evaluated in this study. A target DNA sequence of the plasmodial 18S ribosomal RNA gene was amplified by polymerase chain reaction (PCR) and hybridized in microtiter wells with five biotinylated probes each specific for Plasmodium falciparum, P. vivax, P. malariae, P. ovale and the beta-globine human gene, respectively. Compared to the nested-PCR actually used in our laboratory for the molecular diagnosis of malaria, "Malaria-IBRIDOGEN" revealed an overall sensitivity of 100% (51/51) for the four human Plasmodium species testing 100 whole blood samples from people with malaria-like symptoms and fever. Specificity was 92% (45/49) considering four discordant samples as "false positive" by "Malaria-IBRIDOGEN". The assay showed a threshold of parasite density (detection limit) of 0.07 P. falciparum parasites/microliter, 0.15-1.5 P. vivax parasites/microliter, 0.3 P. malariae parasites/microliter and 0.4 P. ovale parasites/microliter of whole blood, respectively. This assay could be successfully applied to the laboratory diagnosis of malaria as a useful aid to microscopy.

Seroprevalence of HTLV-I and HTLV-II infection among immigrants in northern Italy

To assess the prevalence of human T cell leukemia virus type I (HTLV-I) and 2 (HTLV-II) infection and the associated risk factors among immigrants living in Northern Italy, we surveyed 3017 open-population subjects from three geographical areas and 371 prisoners. In the open population, the overall prevalence was 0.3% for HTLV-I and 0.1% for HTLV-II, while among prisoners, HTLV-I and HTLV-II infection were detected in 1.4 and 0.8% of subjects, respectively. HTLV-I prevalence was higher in subjects with multiple sexual partners or sexually transmitted diseases. This association was significant in the open-population group and close to significance in prisoners. Multivariate analysis showed that human immunodeficiency virus (HIV) seropositivity remained significantly associated with HTLV-I infection in both targeted populations (OR: 11.2 in the open population; OR: 9.9 among prisoners), whereas sexual exposure was associated with HTLV-I seropositivity only for prisoners (OR: 14.3). No independent variable was related to HTLV-II infection.

Identification of Plasmodium falciparum, P. vivax, P. ovale and P. malariae and detection of mixed infection in patients with imported malaria in Italy

The species-specific nested-PCR previously described by Snounou and others for detecting the four parasite species that cause human malaria is evaluated in the current study testing 230 blood samples. The results are compared with those obtained by microscopy and, for 101 samples out of 230, with those previously obtained by a genus-specific PCR based method (pg-PCR) followed by species-specific Southern-blot hybridization. All blood specimens were obtained from patients (127 foreigners and 103 Italians) with a suspect clinical diagnosis of imported malaria in Italy: 76 were positive by microscopy and 83 were positive by nested-PCR. The last method also revealed 10 double infections (8 foreigners and 2 Italians) which were not identified by microscopy or by pg-PCR with species-specific Southern-blot hybridization. Fifty-four out of 83 positive samples tested by nested-PCR were submitted to genomic sequence analysis, which confirmed the presence of DNA region portion encoding the 18S rRNA corresponding to the Plasmodium species identified by nested-PCR. These results demonstrate that the nested-PCR assay surpasses microscopy and pg-PCR with species-specific Southern-blot hybridization, both in sensitivity and in diagnostic accuracy. Moreover, it is quicker because it requires no further blotting or hybridization of PCR amplification products. This method also offers a clear advantage in the detection of mixed infections, which is important not only for successful medical treatment but also for the study of malaria epidemiology. Finally, our study also highlights the value of genomic sequence analysis for validating PCR results.

Usefulness of genus-specific PCR and Southern blot species-specific hybridization for the detection of imported malaria cases in Italy

A PCR method involving a genus-specific oligonucleotides set and Southern blot hybridization with four species-specific probes to P. falciparum, P. vivax, P. malariae and P. ovale was evaluated for the detection of malaria parasites in blood samples from 101 patients with clinically suspect malaria infection imported to Italy. Plasmodium falciparum was the main species detected. As determined by microscopy, 53 (52.4%) patients had malaria and of these: 40 (75.5%) were infected with P. falciparum; 7 (13.2%) with P. vivax; 1 (1.9%) with P. ovale; 3 (5.7%) with P. malariae; 1 (1.9%) with P. vivax or P. ovale; and 1 (1.9%) with P. falciparum or P. vivax. Ninety-seven out 101 blood samples were submitted to ParaSight-F test which showed a sensitivity of 94.73%, and a specificity of 93.22%, as compared to microscopy. The PCR assay using the genus-specific oligonucleotide primer set (pg-PCR) was able to detect 53 (52.4%) infections and showed a sensitivity of 100% and a specificity of 100%, when compared to microscopy. The parasite species were identified by Southern blot hybridization using species-specific probes and 40 (75.5%) samples were P. falciparum positive, 5 (9.4%) P. vivax positive, 4 (7.5%) P. ovale positive, and 2 (3.8%) P. malariae positive. When the Southern blot results were compared to those of blood-film diagnosis, we observed some disagreement. In particular, compared to Southern blot, microscopy underestimated P. ovale infection; blood film analysis recognised only 1 P. ovale sample, whereas Southern blot recognised 4 P. ovale positive samples (by microscopy, 2 of these were detected as P. vivax, 1 as P. ovale or P. vivax, and the other as P. falciparum or P. vivax). Southern blot hybridization was unable to identify one P. falciparum and one P. vivax positive case detected by microscopy. We also plan to use a reference nested-PCR assay to clarify the disagreement observed between microscopy and Southern blot hybridization.

Identification of Mycobacterium xenopi by gas chromatography

For the purposes of the following study we cultured 32 strains of Mycobacterium xenopi isolated from clinical specimens and several strains of other slowly growing mycobacteria. The cultures were grown in liquid medium and then analysed--after saponification, methylation, extraction with organic solvent and washing of the organic phase--using a highly sensitive manual gas-liquid chromatographic assay for the determination of secondary alcohol 2-OH-docosanol. The percentage of this compound was compared with that previously measured in strains of Mycobacterium xenopi grown on solid medium. The presence of this specific alcohol was always apparent, even though its quantity was lower than that obtained by growing mycobacteria on solid medium. The absence of interference peaks around the compound was checked by analyzing strains of other slowly growing mycobacteria in the same conditions.

Evaluation of OptiMAL Assay test to detect imported malaria in Italy

This study evaluated a newly developed rapid malaria diagnostic test, OptiMAL Assay, to detect "Plasmodium falciparum malaria" and "non Plasmodium falciparum malaria" in blood samples from 139 individuals with a presumptive clinical diagnosis of imported malaria in Italy. OptiMAL Assay utilizes a dipstick coated with monoclonal antibodies against the intracellular metabolic enzyme, plasmodium Lactate Dehydrogenase (pLDH) present in and released from parasite-infected erythrocytes. Blood samples from 56 cases out of 139 were found "Plasmodium falciparum malaria" positive by microscopy; with these samples OptiMAL Assay and the ParaSight-F test, which is a kit detecting the P. falciparum histidin-rich protein 2 (HRP-2), showed an overall sensitivity of 83% and 94%, respectively, in comparison with microscopy. Parasitemia levels tested in the 56 P. falciparum positive blood samples by microscopy ranged from <0.004% to 20%. A correlation between sensitivity and parasitemia was evident and OptiMAL Assay and ParaSight-F test were more sensitive (96-100%; 100%) with samples with 0.1%-20% levels of parasitemia, while proved less sensitive (0-44%; 50-88%) with <0.004-0.01% levels of parasitemia.

Search for malaria parasites by PCR and Southern blot in patients with imported malaria in Italy

The present study evaluates the sensitivity, specificity and usefulness of a PCR method with Southern blot hybridization to detect malaria parasites in blood samples from subjects with a suspect clinical diagnosis of malaria imported to Italy. Plasmodia were detected by PCR using a genus-specific primer-set corresponding to the sequences common to P. falciparum, P. vivax, P. malariae and P. ovale, as described by Arai (Arai et al., Nucleosides Nucleotides, 1994, 13, 1363-1364) and Kimura (Kimura et al., Journal of Clinical Microbiology, 1995, 33, 2342-2346). In addition, four distinct tandemly repetitive species-specific probes, described by Kawai (Kawai et al., Analytical Biochimestry, 1993, 209, 63-69), were synthesized to specifically detect the four malaria parasites species by Southern blot hybridization. Fifteen blood samples from 12 patients (7 with malaria) were tested and the genus-specific PCR method showed a sensitivity of 100% and a specificity of 100%, when compared to microscopy, in detecting malaria parasites in the tested blood samples. Fourteen samples (nine were positive and five negative by PCR) were confirmed by Southern blot, whereas only one P. vivax positive sample was not hybridized with the species-specific probes. We conclude that this PCR method with Southern blot hybridization may be useful in detecting malaria parasites in patients with malaria imported to Italy.

Lack of polarized type 1 or type 2 cytokine profile in asymptomatic HIV-1-infected patients during a two-year bimonthly follow-up

The production of type 1 (interferon or IFN-gamma) and type 2 (interleukin or IL-4 and IL-10) cytokines by mitogen-stimulated peripheral blood mononuclear cells (PBMCs) obtained from asymptomatic human immunodeficiency virus-seropositive (HIV+) patients untreated with any antiviral, antibacterial or antimycotic drugs, and from healthy individuals, was evaluated by quantitative ELISA. Patients who were HIV+ were characterized by the absence of abnormal cytokine production. The level of each cytokine differed among individuals in the same group with intersubject variations greater for HIV+ patients than for healthy individuals. The longitudinal evaluation of IFN-gamma, IL-4 and IL-10 production showed intrasubject variations which were particularly marked in HIV+ patients. Accordingly, HIV+ patients and, to a lesser extent, healthy individuals were characterized by a wide spectrum of possible profiles, which were confined to type 0 phenotype. In HIV+ patients no correlation was found between each cytokine level and the number of CD4+ T cells, not even in those with a falling CD4+ T-cell count and clinical symptoms.

Isolation of HTLV-1 from an aggressive form of ATL in a Romanian patient not at risk of infection and with seronegative family members

We present the clinical, virological and haematochemical data of a 22 year old patient from Romania with Adult T Cell Leukaemia (ATL). Viral isolation in peripheral mononuclear blood cells (PMBC), detection of DNA sequences of HTLV-1 by Polymerase Chain Reaction (PCR) and of antibodies by Elisa and Western blot were performed. The patient does not belong to any risk group and additionally all members of her family are seronegative for HTLV-1, the aetiological agent of ATL. The role of viral infection remains open.

Diagnosis of bronchopulmonary infections by quantification of microflora

The quantification of bacteria and fungi in sputum or bronchoaspirate is of clinical value for the diagnosis of respiratory tract infections. We have developed an easy method to count the micro-organisms in patients with respiratory tract infections. This consists of the quantification of micro-organisms by subsequent streakings of a calibrated loop on agar. The correlation between microbiological quantitative data and the clinical status of patients with lower respiratory tract infections is discussed. The data seem to indicate that certain bacteria present in sputum or bronchoaspirate above a certain concentration may be responsible for lower respiratory tract infections. In patients with immunological disorders or chronic pathologies even lower concentrations of micro-organisms in bronchial secretions probably are enough to cause infections. The advantage of this counting method of the microbic species from the respiratory tract consists of their quantification: thus we can attribute an etiological role to a high concentration of the germs, while micro-organisms at low concentrations are probably contaminants. By this method isolated colonies are obtained after 12-18 hours. The bacterial quantification, by respiratory samples examination of the same patient in the following days, allows us to evaluate the efficacy of antibacterial therapy, producing a reduction of bacterial concentration.

Persistence of human T cell lymphotropic virus type 1 (HTLV-1) sequences in peripheral blood mononuclear cells from patients with mycosis fungoides

Mycosis fungoides (MF) is a rare form of cutaneous T cell lymphoma suspected of having a viral etiology. As in adult T cell leukemia, the virus involved may be human T lymphotropic virus type 1 (HTLV-1). We cultured the peripheral blood mononuclear cells (PBMC) of 29 patients with MF HTLV-1 seronegative by enzyme-linked immunosorbent assay and Western blot. The presence of reverse transcriptase (RT) and p24 antigen was investigated in the concentrate supernatant of the culture. The DNA of all studied patients was submitted to polymerase chain reaction and Southern blot analysis using primers and probes recognizing the tax region of HTLV-1/2 and the pol region of HTLV-1. 10 of 29 patients were found positive to HTLV-1, whereas they were always negative to RT and p24. The same results were confirmed in double blind after 6 mo. Our findings suggest HTLV-1 may be involved in the etiology of MF, at least in certain cases.

Flow cytometric indirect immunofluorescence assay with high sensitivity and specificity for the detection of antibodies to HSV-1 and HSV-2

Cells infected with HSV-1 or HSV-2 develop viral antigens which can be detected by immunofluorescence. We developed a flow cytometric indirect immunofluorescence assay to detect and quantitate antibodies to HSV-1 and HSV-2 in human sera. Results obtained by flow cytometry for detecting antibodies against HSV-1, when compared with results obtained by ELISA, showed an index of overall agreement of 100%. The correlation between the antibody titers obtained with each method was found to be highly significant. An index of overall agreement equal to 94.1% was observed between results obtained by flow cytometry and by immunofluorescence as concerns the discrimination of HSV-2 positive from negative samples. However, the correlation between antibody titers was found to be not statistically significant. The flow cytometric assay proved to be type-specific.