Forensic investigation on a combined death by food aspiration and acute escitalopram intoxication occurred to a psychiatric subject in a nursing home.

Food aspiration is one of the major health risks for elderly people in nursing homes which could lead to death. Moreover, misconducts in pharmacotherapy may represent a potential risk of adverse drug reactions. It is reported here the toxicological evaluation of a combined death by food aspiration and acute escitalopram intoxication of a psychiatric subject, occurred in a nursing home. An 89-year-old man, suffering from dysphagia and Alzheimer's, was resident in a nursing home. He was fed with a liquid diet administered directly in mouth using a syringe. The man was also being treated with escitalopram 10 mg tablet. One evening, after receiving the meal in the usual way, the man complained of sudden illness. Carried to the emergency room, the man died about 3 h later with a diagnosis of cardiogenic shock subsequentially to ab ingestis. The histological findings revealed the presence of exogenous material, probably food, up to the finest bronchial branches. The toxicological examination revealed the presence of escitalopram and its main metabolite, desmethylcitalopram: in the blood 1972 ng/ml and 285 ng/ml, in the brain 4657 ng/g and 1025 ng/g, in the gastric content 2317 ng/g and 423 ng/g, in the lung 21,771 ng/g and 468 ng/g, respectively. The bad practice of the nurses to dissolve the escitalopram tablet in the liquefied food and to administer the therapy with a syringe directly into the mouth emerged thanks this investigation. Following food aspiration, escitalopram was absorbed by inhalation route, reaching high concentrations in blood and tissues. The death occurred due to a combined mechanism between food aspiration and the escitalopram toxic action.

Cryptococcal meningitis in an HIV-1-infected person: relapses or IRIS? Case report and review of the literature.

After starting highly active antiretroviral therapy (HAART), HIV-infected patients may experience what is termed immune reconstitution inflammatory syndrome (IRIS). IRIS is characterized by a paradoxical inflammatory response to either previously or recently treated infections or unmasked subclinical infections, when the patient regains the ability to mount a suitable immune response against specific antigens or pathogens. Cryptococcal IRIS (C-IRIS) is thought to be mediated by recovery of Cryptococcus-specific immune responses, resulting in exaggerated host inflammatory responses. In HIV-positive subjects, two distinct modes of presentation of C-IRIS are recognized, "paradoxical" and "unmasking" C-IRIS. "Paradoxical" C-IRIS presents as worsening or recurrence of treated cryptococcal disease following HAART initiation, despite microbiological treatment success. In the "unmasking" form, patients with no prior diagnosis may develop acute symptoms of cryptococcosis, such as meningitis or necrotizing lymphadenopathy, after starting HAART. Here, we present the case of an HIV-positive man, who developed cryptococcal meningitis two months after having started HAART and experienced several meningeal relapses and a "paradoxical" C-IRIS during the following year.

LPS and HIV gp120 modulate monocyte/macrophage CYP27B1 and CYP24A1 expression leading to vitamin D consumption and hypovitaminosis D in HIV-infected individuals.

AIM: Vitamin D deficiency is very common among HIV-infected subjects. We cross-sectionally evaluated the prevalence and risk factors for hypovitaminosis D in 91 HIV-infected Italian patients. PATIENTS AND METHODS: We studied in a cohort of 91 HIV-infected Italian patients the metabolism of Vitamin D by evaluating the in vitro expression of CYP27B1, CYP24A1 and vitamin D receptor (VDR) by monocytes and macrophages stimulated with the viral envelope protein gp120 or lipopolysaccharide (LPS). RESULTS: The prevalence of vitamin D deficiency (25OHD < 10 ng/ml) and vitamin D insufficiency (25OHD 10-30 ng/ml) was 31% and 57%, respectively. In univariate analysis, female sex (p = 0.01), increasing age (p = 0.05), higher highly sensitive-C reactive protein (p = 0.025), higher parathyroid hormone (PTH) (p = 0.043) and lower BMI (p = 0.04) were associated with vitamin D deficiency. In multivariate analysis, the association was still significant only for PTH (p = 0.03) and female sex (p = 0.03). Monocyte stimulation with LPS (100 ng/ml) or gp120 (1 µg/ml) significantly upregulated CYP27B1 mRNA expression. Moreover, gp120 significantly increased VDR mRNA levels. On the contrary, neither LPS nor gp120 modified CYP24A1 levels. Macrophage stimulation with LPS (100 ng/ml) significantly upregulated CYP27B1 and CYP24A1 mRNA expression. When monocytes were cultured in the presence of 25OHD (40 ng/ml) and stimulated with LPS we detected significantly lower levels of 25OHD in the supernatant. CONCLUSIONS: Vitamin D deficiency was very common in our cohort of HIV-infected patients. Chronic inflammation, including residual viral replication, may contribute to hypovitaminosis D, by modulating vitamin D metabolism and catabolism. Systematic screening may help identifying subjects requiring supplementation.

Late presentation of HIV infection: predictors of delayed diagnosis and survival in Eastern Sicily.

OBJECTIVES: Across Europe, more than one third of patients are diagnosed with HIV infection late. Late presentation for care has been associated with higher risk of clinical progression and mortality. In the present study, we evaluated the prevalence, epidemiological characteristics and survival probability of patients with late and very late presentation, newly diagnosed with HIV infection in Catania, Italy, from 1985 to 2010. PATIENTS AND METHODS: According to the European Consensus definition, Late Presenters (LP) were defined as subjects presenting for care with a CD4+ T-cell count below 350 cells/µl or with an AIDS-defining event, regardless of CD4+ T-cell count; patients with advanced HIV disease (Very Late Presenters) (VLP) were those presenting with a CD4+ T-cell count below 200 cells/µl or with an AIDS-defining event, regardless of CD4+ T-cell count. RESULTS: 620 patients were included in the study. 345 (55.6%) subjects were LP, 35% of them were asymptomatic; 246 (39.7%) were VLP. In univariate analysis, late presentation was related to age (p < 0.001), to heterosexual exposure to HIV infection (70% of heterosexual subjects were LP) (p < 0.005) and to being diagnosed during the calendar period from 1991 to 2000 (p < 0.001). Very late presentation was related to age (p < 0.001), male sex (p < 0.01), heterosexual risk (p < 0.001) and to being diagnosed during the calendar period from 1991 to 2000 (p < 0.001). In multivariate analysis, age (p < 0.0001), being older than 50 years old (p = 0.02), years of diagnosis 1991-1995 (p < 0.005) and 1996-2000 (p < 0.05) in the subgroup of late presenters and age (p < 0.0001), being older than 50 years old (p < 0.005), male sex (p < 0.0001), years of diagnosis 1991-1995 (p < 0.05) and 1996-2000 (p < 0.005) in the subgroup of very late presenters maintained statistical significance. The survival probability within LP and VLP group was statistically lower than no LP/VLP (log rank test p < 0.0005 and p < 0.0001, respectively). For both LP (p < 0.002) and VLP (p < 0.0001), survival probability was significantly lower in the pre-HAART era, in comparison with the period of mono/dual therapy and the HAART era. CONCLUSIONS: More than fifty percent of patients in our setting were diagnosed late with HIV infection and, consequently, treated late. Late and very late presentation were associated with lower survival probability. The implementation of strategies focused on targeted prevention efforts and HIV testing programs appears fundamental to diagnose and treat HIV infection as early as possible.

Use of PCR-restriction fragment length polymorphism analysis for identification of yeast species isolated from bovine intramammary infection.

This study reports a rapid PCR-based technique using a one-enzyme RFLP for discrimination of yeasts isolated from bovine clinical and subclinical mastitis milk samples. We analyzed a total of 1,486 milk samples collected over 1 yr in south Sardinia and northern Italy, and 142 yeast strains were preliminarily grouped based on their cultural morphology and physiological characteristics. Assimilation tests were conducted using the identification kit API ID 32C and APILAB Plus software (bioMérieux, Marcy l'Etoile, France). For PCR-RFLP analysis, the 18S-ITS1-5.8S ribosomal(r)DNA region was amplified and then digested with HaeIII, and dendrogram analysis of RFLP fragments was carried out. Furthermore, within each of the groups identified by the API or PCR-RFLP methods, the identification of isolates was confirmed by sequencing of the D1/D2 region using an ABI Prism 310 automatic sequencer (Applied Biosystems, Foster City, CA). The combined phenotypic and molecular approach enabled the identification of 17 yeast species belonging to the genera Candida (47.9%), Cryptococcus (21.1%), Trichosporon (19.7%), Geotrichum (7.1%), and Rhodotorula (4.2%). All Candida species were correctly identified by the API test and their identification confirmed by sequencing. All strains identified with the API system as Geotrichum candidum, Cryptococcus uniguttulatus, and Rhodotorula glutinis also produced characteristic restriction patterns and were confirmed as Galactomyces geotrichum (a teleomorph of G. candidum), Filobasidium uniguttulatum (teleomorph of Crypt. uniguttulatus), and R. glutinis, respectively, by D1/D2 rDNA sequencing. With regard to the genus Trichosporon, preliminary identification by API was problematic, whereas the RFLP technique used in this study gave characteristic restriction profiles for each species. Moreover, sequencing of the D1/D2 region allowed not only successful identification of Trichosporon gracile where API could not, but also correct identification of misidentified isolates. In conclusion, the 18S-ITS1-5.8S region appears to be useful in detecting genetic variability among yeast species, which is valuable for taxonomic purposes and for species identification. We have established an RFLP database for yeast species identified in milk samples using the software GelCompar II and the RFLP database constitutes an initial method for veterinary yeast identification.

Lethal vortioxetine poisoning? A forensic investigation.

Vortioxetine is an antidepressant recently licensed in the US and EU for the treatment of major depressive disorder. No fatalities from vortioxetine overdose have been reported, yet. Two cases of attempted suicide are described in the literature, although no toxicological analyzes were conducted. Vortioxetine concentrations found in blood and organs in a case of a probable acute lethal intoxication are reported here. A 65-year-old woman was found on the floor behind her bed with no vital signs. The woman was recently on vortioxetine 10 mg/day for major depression, anxiety, and psychotic attacks. Vortioxetine was quantified in blood, brain, liver, kidney, and lung samples by LC-MS/MS. Vortioxetine concentrations were: 1.197 ng/ml in the blood, 804 ng/g in the brain, 8.992 ng/g in the lung, 1.389 ng/g in the liver, 292 in the kidney. No other substance was found. In the case reported here, the blood concentration was approximately 35-135 times higher than the antemortem therapeutic value. Histological examination showed signs of a probable sudden cardiac death following to arrhythmia, with no evidence of myocardial infarction. The present case indicate that blood concentrations close to 1,000 ng/mL could lead to death, involving probably to a cardiac toxicity.

Hepatocellular carcinoma in HIV positive patients.

Highly active antiretroviral therapy (HAART) has dramatically changed the natural history of HIV-1-infected patients leading to increased survival and a better quality of life. Hepatitis C virus (HCV) and hepatitis B virus (HBV) infections are common among HIV-1-infected subjects and represent the most important risk factors for hepatocellular carcinoma (HCC). Whether HIV plays a direct role in hepatocellular carcinoma (HCC) pathogenesis remains to be established.HCC clinical course depends on stage of cancer disease, performance status and comorbidities. Therapeutic options include liver transplantation, local antiblastic chemotherapy and biological drugs. In the HIV setting few data are available about treatment options. The increased longevity of patients with HIV imposes new strategies for prevention and therapeutic management of patients. The aim of this article is to provide an up-to-date review of HIV-related HCC in the HAART era.

Molecular detection of virulence factors and antibiotic resistance pattern in clinical Enterococcus faecalis strains in Sardinia.

In this study, the antibiotic resistance pattern and the presence of genes encoding several virulence factors in 91 Enterococcus faecalis strains isolated from different human clinical sources in Sardinia were investigated. Genotypic determination of virulence genes (gelE, esp, agg, ace, cylA,B,M,L(L),L(S), efaA, fsrB) was carried out by PCR. The production of gelatinase and haemolytic activity were also determined. Antimicrobial susceptibility tests were performed by an automated microdilution test (Vitek). The strains examined in this study contained at least one and up to as many as all virulence genes investigated. Examining the distribution of these factors in the different groups of clinical strains, we found that all but one virulence determinant were detected more frequently among urinary isolates. The detection of some factors by PCR did not always correlate with its phenotypic expression. Antibiotic susceptibilities among the Enterococcus faecalis strains investigated in our study were typical for the species, with expected levels of acquired resistance. Faecal isolates had the highest percentage of resistance, especially to high level-gentamicin, ciprofloxacin and norfloxacin. In summary, a wide variety of genes encoding virulence factors have been detected among our clinical Enterococcus faecalis strains, and those isolated from UTI were characterized by a higher virulence potency compared with strains from other clinical sources. Silent virulence genes (cyl or gelE) were frequently detected, therefore both the genotypic and phenotypic assays seem necessary for a better characterization of the strains. Our results may serve as a basis for additional surveillance studies of infections caused by this microorganism.

[Phenotypic and molecular characterization of Candida species in ICU]. / Caratterizzazione fenotipica e molecolare di Candida isolate in un reparto di Terapia Intensiva.

Two hundred sixty three Candida isolates were obtained from specimens of patients hospitalized in a Intensive Care Unit. Candida albicans was the predominant species, followed by C. tropicalis, C. krusei, C. glabrata e C. parapsilosis. For C. albicans isolates, amphotericin B was the more efficient antifungal (2.3% of resistant strains), while voriconazole was the more efficient for C. krusei and C. glabrata, known for their lower susceptibility to fluconazole. RAPD-PCR technique with CDU primer was used for the molecular characterization of 48 C. albicans strains isolated from 10 patients. Genetic similarity at 90% level was observed for some Candida strains isolated from the same patient, indicating a possible colonization from the original strain. Moreover the high similarity coefficient observed between isolates from different patients may indicate an exogenous colonization originating from hospital-endemic strains or inadequate manipulation by health care workers.

Free carrier enhanced depletion in ZnO nanorods decorated with bimetallic AuPt nanoclusters.

The decoration of semiconductor nanostructures with small metallic clusters usually leads to an improvement of their properties in sensing or catalysis. Bimetallic cluster decoration typically is claimed to be even more effective. Here, we report a detailed investigation of the effects of Au, Pt or AuPt nanocluster decoration of ZnO nanorods on charge transport, photoluminescence and UV sensitivity. ZnO nanorods were synthesized by chemical bath deposition while decoration with small nanoclusters (2-3 nm in size) was achieved by a laser-ablation based cluster beam deposition technology. The structural properties were investigated by scanning electron microscopy, high resolution transmission electron microscopy, X-ray photoelectron spectroscopy and Rutherford backscattering spectrometry, and the optoelectronic properties by current-voltage and photoluminescence measurements. The extent of band bending at the cluster-ZnO interface was quantitatively modeled through numerical simulations. The decoration of ZnO nanorods with monometallic Au or Pt nanoclusters causes a significant depletion of free electrons below the surface, leading to a reduction of UV photoluminescence, an increase of ZnO nanorod dark resistance (up to 200 times) and, as a consequence, an improved sensitivity (up to 6 times) to UV light. These effects are strongly enhanced (up to 450 and 10 times, respectively) when ZnO nanorods are decorated with bimetallic AuPt nanoclusters that substantially augment the depletion of free carriers likely due to a more efficient absorption of the gas molecules on the surface of the bimetallic AuPt nanoclusters than on that of their monometallic counterparts. The depletion of free carriers in cluster decorated ZnO nanorods is quantitatively investigated and modelled, allowing the application of these composite materials in UV sensing and light induced catalysis.

Prevalence of Candida species in different hospital wards and their susceptibility to antifungal agents: results of a three year survey.

Over a three years period, 472 Candida isolates were obtained from specimens of patients hospitalized either in "at risk", Bone Marrow Transplant Unit and Intensive Care Unit, or in conventional wards, Pneumological Divisions of the "Binaghi" Hospital of Cagliari (Italy). Antifungal susceptibility profile to amphotericin B, voriconazole, fluconazole and ketoconazole was determined. Candida albicans was the predominant species while Candida krusei was the most frequent non-albicans species. C. krusei was significantly more common among Bone Marrow Transplant Unit and Intensive Care Unit than Pneumological Divisions patients (17.9% and 14.1% vs. 6.0%; p < 0.05). No significant differences were observed when the same distribution was analysed with regard to the other Candida species or when Bone Marrow Transplant Unit and Intensive Care Unit were compared. The profiles of susceptibility to the antifungal drugs among isolates from the different hospital wards showed no significant differences, even though most of MIC values were higher for Intensive Care Unit isolates compared to those for Bone Marrow Transplant Unit and Pneumological Divisions. For C. albicans isolates, amphotericin B was the more efficient antifungal (97.7% S), while fluconazole (6.1% R [Resistant] and 2.6% SDD [Susceptible Dose Dependent]) and ketoconazole (4.1% R and 3.2% SDD) showed the lowest activity. Voriconazole was the more efficient antimycotic for C. krusei (96.7% S) and Candida glabrata (100% S [Sensible]) isolates. This study has shown a significantly higher presence of non-albicans Candida in at risk wards as well as a decreased susceptibility to the older azoles (ketoconazole and fluconazole) among C. albicans isolates.

Knee extensor muscular activity estimation during different walking patterns: flat normal and brisk walking, stair climbing.

Preserving mobility, the ability to keep a correct posture and dynamic balance in order to walk properly, is fundamental to maintain autonomy in daily life. Based on the correlation between muscle groups and autonomy, previous research has suggested that maintaining muscular tone in knee extensors is critical. Continuous training of knee extensors during aging is therefore essential to maintain independence. In this work, it is hypothesized that it is possible to estimate knee extensor activity only from IMU data based on a simple lower limbs model. The accuracy of the knee extensor activity estimation algorithm has been tested using sEMG measurements as control data on three different walking patterns: normal walk, fast walk and stair climbing. Estimated knee torque area and measured muscular activity for each step were compared confirming a high estimation accuracy with a correlation efficient R=0.80. Moreover, muscular activity can be divided based on intensity in three groups of statistically significant difference confirmed by the Steel-Dwass method. Future works should test the usability of the algorithm for different walking patterns, and use the collected data and the refined algorithm to implement a smart resistive device to increase knee extensor exertion during each walking pattern to the level necessary for sufficient extensor training.

Loss of thrombospondin transcriptional activity in nickel-transformed cells.

mRNA from normal Chinese hamster embryo (CHE) cells was transcribed to cDNA and subtracted with an excess of mRNA from Chinese hamster embryo cells transformed by nickel compounds. Here we report the recovery of a sequence found to be highly homologous to the mouse thrombospondin 1 gene that was obtained by this subtraction procedure. Since thrombospondin is antiangiogenic, cancer cells expressing high levels of thrombospondin cannot grow in vivo because capillaries will not proliferate to cells secreting thrombospondin. To examine expression of thrombospondin, normal CHE cells were stained with monoclonal antibodies to human thrombospondin. The protein was present abundantly in the cytoplasm of normal cells but at greatly reduced levels in Ni-transformed cells. Analysis of mRNA by Northern (RNA) blot revealed transcripts in normal cells but little thrombospondin mRNA in Ni-transformed cells. Loss of thrombospondin mRNA expression was related to Ni treatment rather than transformation, since Ni-resistant cells also exhibited fewer thrombospondin transcripts than did wild-type cells. Digestion of genomic DNA with various combinations of restriction enzymes revealed thrombospondin gene patterns that were identical in both cell types, suggesting that there were no major deletions or rearrangements of the gene in the nickel-transformed cells. The inactivation of the thrombospondin gene was further investigated by analyzing the promoter activity of this gene linked to a chloramphenicol acetyltransferase (CAT) reporter plasmid that was transfected into normal and Ni-transformed cells. The CAT activity in normal cells was significantly higher than in Ni-transformed cells, suggesting that the promoter region of thrombospondin was less efficiently transcribed in Ni-transformed cells. We studied the consequences of enhanced expression of the retinoblastoma (Rb) gene, a known tumor suppressor gene, on CAT transcription driven by the human thrombospondin promoter. Cotransfection of an expression vector containing the mouse Rb gene greatly enhanced the transcription from the thrombospondin promoter such that the expression was higher in normal cells than in transformed cells.

First Report of Southern Blight Caused by Sclerotium rolfsii on Hemp (Cannabis sativa) in Sicily and Southern Italy.

Hemp (Cannabis sativa L.), family Cannabaceae, is an annual herbaceous plant that is 1.5 to 4.0 m tall and native to the Caucasus Region, northern India, and Iran. It is cultivated in warm to temperate regions worldwide for its fiber, oil, and psychoactive substances. In Europe, commercial plantings have decreased from 52,872 ha in 1989 to 18,716 ha in 2005. Recently however, cultivation of hemp as a natural fiber species has been encouraged by European Union policy (2). During the summer of 2003, patches of dead plants were observed in test plots of 12 monoecious and dioecious hemp cultivars (Beniko, Epsylon 68, Felina 34, Ferimon, Fedora 17, Futura 75, Bialobrzeskie, Dioica 88, Fibranova, Tiborszallasi, Lovrin, and Carmagnola) in an experimental field near Catania (eastern Sicily) previously planted to artichoke (Cynara scolymus L.). Plots were irrigated with a drip irrigation system. Symptoms were first detected in July with day/night temperatures between 35 and 26°C. Infected plants showed a dark brown-to-tan discoloration of the stem near the soil line. As disease progressed, the rot extended down to the crown and taproot, foliage became yellow, and the entire plant eventually collapsed. An extensive white, cottony mycelium and numerous spherical tan-to-dark brown sclerotia (0.5 to 4.0 mm in diameter) developed externally on infected tissues and soil. As much as 60% of the plants were affected in a single plot. Monoecious cultivars that had been planted earlier escaped the disease. Isolations from diseased tissues were performed by plating symptomatic tissues previously disinfected for 1 min in 1% NaOCl and rinsed in sterile water on acidified potato dextrose agar (pH 4.5). Isolations consistently yielded a fungus whose characters corresponded to Sclerotium rolfsii Sacc. (teleomorph Athelia rolfsii (Curzi) Tu & Kimbrough). Pathogenicity of two isolates obtained from infected plants was confirmed by inoculating 120-day-old hemp plants grown in individual pots. Twenty plants for each of the above listed cultivars (10 plants for each isolate) were inoculated by applying toothpick tips (5 mm) colonized by S. rolfsii to the lower part of the stem. Ten noninoculated plants served as controls. Plants were kept in a greenhouse with temperatures between 26 and 32°C and 95% relative humidity. High soil moisture was maintained with frequent watering. All inoculated plants showed blight and basal stem rot after 2 weeks, irrespective of the cultivar. By the third week, plants began to dry up and mycelium and sclerotia developed on the crown. Noninoculated controls remained symptomless. S. rolfsii was reisolated from inoculated plants. Although S. rolfsii has been reported on hemp in India since the 1930s (3), to our knowledge, this is the first report of southern blight caused by this fungus on C. sativa in Sicily and southern Italy. Residues of artichoke, a very susceptible host of S. rolfsii (1), might have been the source of inoculum for this outbreak on hemp. Most likely, high summer temperatures and overirrigation exacerbated the disease severity. References: (1) C. Cariddi and R. Lops. La Difesa delle Piante 19(1):27, 1996. (2) S. L. Cosentino et al. Agroindustria 2:137, 2003. (3) G. P. Hector. Ann. Rep. Dep. Agric. Bengal 35, 1931.

Angular sway propagation in One Leg Stance and quiet stance with Inertial Measurement Units for older adults.

Postural stability degrades with age, threating the health and life quality of the older adults. One Leg Stance (OLS) is one of the standard and commonly adopted assessments for postural stability, and the postural sway in OLS has been demonstrated to be related with age. The propagation of postural sway between body segments could be a hint to the underlying mechanism of balance control. However, it is not yet fully understood. Therefore, the aim of this paper was to study the angular sways and their propagation of the head, trunk, and lower limb in healthy older adults. A cross-correlation of the normalized angular speeds was performed and the experiment with 68 older adults was conducted. The results showed that the head, hip and ankle joints affected the transfer of angular sway with a relatively lower correlation and longer latency.

The role of the interface in germanium quantum dots: when not only size matters for quantum confinement effects.

Quantum confinement (QC) typically assumes a sharp interface between a nanostructure and its environment, leading to an abrupt change in the potential for confined electrons and holes. When the interface is not ideally sharp and clean, significant deviations from the QC rule appear and other parameters beyond the nanostructure size play a considerable role. In this work we elucidate the role of the interface on QC in Ge quantum dots (QDs) synthesized by rf-magnetron sputtering or plasma enhanced chemical vapor deposition (PECVD). Through a detailed electron energy loss spectroscopy (EELS) analysis we investigated the structural and chemical properties of QD interfaces. PECVD QDs exhibit a sharper interface compared to sputter ones, which also evidences a larger contribution of mixed Ge-oxide states. Such a difference strongly modifies the QC strength, as experimentally verified by light absorption spectroscopy. A large size-tuning of the optical bandgap and an increase in the oscillator strength occur when the interface is sharp. A spatially dependent effective mass (SPDEM) model is employed to account for the interface difference between Ge QDs, pointing out a larger reduction in the exciton effective mass in the sharper interface case. These results add new insights into the role of interfaces on confined systems, and open the route for reliable exploitation of QC effects.

Molecular mechanisms of nickel carcinogenesis.

Carcinogenic, water-insoluble Ni compounds are phagocytized by cells; and the particles undergo dissolution inside the cell, releasing Ni ions that interact with chromatin. Ni produces highly selective damage to heterochromatin. The longest contiguous region of heterochromatin in the Chinese hamster genome is found on the q arm of the X chromosome, and this region is selectively damaged by Ni. More than half of the male mice in which there were Ni-induced transformations of Chinese hamster cells exhibited complete deletion of the long arm of the X chromosome. The introduction of a normal X chromosome into these cells resulted in cellular senescence, suggesting that the Ni interacted with Chinese hamster genome to inactivate a senescence gene. Investigations were conducted into the mechanisms by which Ni produced damage to chromatin. Ni ions have a much higher affinity for proteins and amino acids than for DNA (by five to seven orders of magnitude). Therefore, Ni interacted with chromatin because of the protein present, not because of its reactivity for DNA. Studies have shown that Ni produced an increase in oxidative products in cells as indicated by oxidation of the fluorescent dye dichlorofluorescein; Ni has also been shown to produce oxidation of proteins in cells, as measured by carbonyl formation. Ni cross-linked certain amino acids and proteins to DNA. These covalent cross-links were not dissociated by EDTA and are inconsistent with direct Ni involvement, but they are consistent with Ni acting catalytically. Using subtractive hybridization, we have isolated a number of clones that are expressed in normal but not in Ni-transformed cells.(ABSTRACT TRUNCATED AT 250 WORDS)

Metal mutagenesis in transgenic Chinese hamster cell lines.

Metals are toxic agents for which genotoxic effects are often difficult to demonstrate. To study metal mutagenesis, we have used two stable hprt/gpt+ transgenic cell lines that were derived from Chinese hamster V79 cells. Both the G12 and G10 cell lines are known to be very sensitive to clastogens such as X-rays and bleomycin, with the mutagenic response of the integrated xanthine guanine phosphoribosyl transferase (gpt) gene in G10 usually exceeding that of the same gene in the transgenic G12 cells. In studies with carcinogenic insoluble nickel compounds, a high level of mutagenesis was found at the gpt locus of G12 cells but not at the endogenous hypoxanthine phosphoribosyl transferase (hprt) locus of V79 cells. We have since demonstrated the similar recovery of a high frequency of viable G12 mutants with other insoluble nickel salts including nickel oxides (black and green). The relative mutant yield for the insoluble nickel compounds (G12 > G10) is the opposite of that obtained with nonmetal clastogens (G10 > G12). In the G12 cells, nickel mutagenesis may be related to the integration of the gpt sequence into a heterochromatic region of the genome. For some of the insoluble nickel compounds, significant inhibition of both cytotoxicity and mutant yield resulted when the G12 cells were pretreated with vitamin E. In comparison with the nickel studies, the mutagenic responses to chromium compounds in these cell lines were not as dramatic. Mutagenesis of the gpt target could not be demonstrated with other metals such as mercury or vanadium.

HCV and HIV infection among intravenous drug abusers in eastern Sicily.

In a study of 175 intravenous drug addicts from Eastern Sicily, 58.3% were found to be anti-HCV positive. In this population, the presence of anti-HCV was independent of HIV infection, age, duration of drug use and the practice of needle sharing. This may indicate that HCV is more readily transmitted (or spread earlier in this population) among drug addicts than is HIV.

Preliminary investigation on intrafamilial spread of hepatitis C virus (HCV).

To determine the risk of cohabitant HCV infection, we investigated the sera of 101 family members of 53 anti-HCV antibody positive chronic liver disease patients. Altogether 14.8% of the cohabitants were also anti-HCV antibody positive, compared to a prevalence of 1.4% in the general population. These results suggest that hepatitis-C-virus may spread by person-to-person infection.