Biomedical subjects

N Altavilla

Publications and source records attributed to N Altavilla.

8 recordsLinked to original sources

PubMed2005

Environmental inactivation of Cryptosporidium oocysts in catchment soils.

AIMS: To generate field-relevant inactivation rates for Cryptosporidium oocysts in soil that may serve as parameter values in models to predict the terrestrial fate and transport of oocysts in catchments. METHODS AND RESULTS: The inactivation of Cryptosporidium oocysts in closed soil microcosms over time was monitored using fluorescence in situ hybridization (FISH) as an estimate of oocyst 'viability'. Inactivation rates for Cryptosporidium in two soils were determined under a range of temperature, moisture and biotic status regimes. Temperature and soil type emerged as significantly influential factors (P < 0.05) for Cryptosporidium inactivation. In particular, temperatures as high as 35 degrees C may result in enhanced inactivation. CONCLUSIONS: When modelling the fate of Cryptosporidium oocysts in catchment soils, the use of inactivation rates that are appropriate for the specific catchment climate and soil types is essential. FISH was considered cost-effective and appropriate for determining oocyst inactivation rates in soil. SIGNIFICANCE AND IMPACT OF THE STUDY: Previous models for predicting the fate of pathogens in catchments have either made nonvalidated assumptions regarding inactivation of Cryptosporidium in the terrestrial environment or have not considered it at all. Field-relevant inactivation data are presented, with significant implications for the management of catchments in warm temperate and tropical environments.

Animals↗

PubMed2001

Potential problems with fluorescein diacetate assays of cell viability when testing natural products for antimicrobial activity.

There are two potential problems in the use of fluorescein diacetate (FDA) as a measure of cell viability. The first is the hydrolysis of FDA to fluorescein in the absence of live cells and the second is the quenching of fluorescence by assay solutions. We show that common media components such as tryptone, peptone and yeast extract all promote hydrolysis of FDA in the absence of live cells, as do Tris-HCl and sodium phosphate buffers. As a consequence, various microbiological media promote hydrolysis of FDA in the absence of live cells. Different media were also shown to reduce the amount of visible fluorescence of fluorescein. Diluting the medium decreases the background hydrolysis of FDA as well as increases the amount of visible fluorescence. Both problems should be considered when using FDA as an indicator of cell viability when testing natural products for antimicrobial activity.

Anti-Infective Agents↗

PubMed2001

Incidence of autoimmune thyroiditis in interferon-alpha treated and untreated patients with chronic hepatitis C virus infection.

OBJECTIVES: To clarify the relationship between interferon-alpha (IFN-alpha) therapy and autoimmune thyroiditis in chronic hepatitis C virus (HCV) infection, we investigated a selected number of patients without basal thyroid dysfunctions. MATERIALS AND METHODS: 130 patients (average age: 20-70), with chronic HCV infection and without basal clinical and laboratory signs of autoimmune thyroiditis were divided into two groups: IFN-alpha treated (A) and untreated (B) patients. Group A received IFN-alpha (three million U.I./3 times a week) for six months; group B was followed for the same period. Thyroid peroxidase and thyroglobulin autoantibodies were measured by radioimmunoassay; thyroid function was measured by radioimmunoassay (free thyroxine and triiodothyronine) and immunoradiometric assay (thyroid stimulating hormone). RESULTS: After a 6-month period, thyroid autoantibodies positivity was documented in 21.1% of group A and in 10.3% of group B patients, both statistically relevant (p<0.001 and p<0.011, respectively). The comparison between the two groups was not statistically relevant (p=0.142). CONCLUSIONS: Our study showed a prevalence of de novo thyroid autoimmunity in chronic HCV patients treated with IFN-alpha, confirming previous data in literature. The lack of a significant difference between treated and untreated patients strongly suggests that the anti-thyroid autoimmune response is linked to the HCV infection itself. Moreover, IFN-alpha therapy probably does not represent a risk factor in renewing the autoimmune processes of the thyroid gland. Thyroid function and autoantibodies must be systematically monitored in patients with HCV infection, especially in female and IFN-alpha treated population, not only to verify the possible thyroid abnormalities but also to rule out concomitant autoimmune diseases.

Adult↗

PubMed1999

Sphingomonas paucimobilis BPSI-3 mutant AN2 produces a red catabolite during biphenyl degradation.

The biphenyl degradation pathway of Sphingomonas paucimobilis BPSI-3 was investigated using a degradation-deficient mutant generated by 1-methyl-3-nitro-1-nitrosoguanidine (NTG) mutagenesis. The mutant, designated AN2, was confirmed as originating from BPSI-3 through the use of ERIC (Enterobacterial Repetitive Intergenic Consensus) PCR and by detection of the diagnostic pigment, nostoxanthin, in cellular methanol extracts. Mutant AN2 produced a yellow followed by red extracellular substance when grown in the presence of biphenyl. In the presence of 2,3-dihydroxybiphenyl, yellow followed by red then yellow compounds were formed over time. This colour change was consistent with the characteristics of a quinone, 1-phenyl-2,3-benzoquinone, which could arise from the oxidation of 2,3-dihydroxybiphenyl. A quinone was synthesised from 2,3-dihydroxybiphenyl and compared to the red compound produced by mutant AN2. Gas chromatography-mass spectrophotometry (GC-MS) confirmed that a similar quinone (4,5-dimethoxy-3-phenyl-1,2-benzoquinone) compared to the structure of the proposed biogenic compound, had been formed. This compound was also found after GC-MS analysis of mutant AN2 culture extracts. Spectrophotometric analysis of the quinone synthesised and the red product produced revealed almost identical spectral profiles. A likely inference from this evidence is that the mutant AN2 is blocked, or its activity altered, in the first gene cluster, bphA to C, of the biphenyl degradation pathway.

Journal Article↗

PubMed1998

Methods for microbial DNA extraction from soil for PCR amplification.

Amplification of DNA from soil is often inhibited by co-purified contaminants. A rapid, inexpensive, large-scale DNA extraction method involving minimal purification has been developed that is applicable to various soil types (1). DNA is also suitable for PCR amplification using various DNA targets. DNA was extracted from 100g of soil using direct lysis with glass beads and SDS followed by potassium acetate precipitation, polyethylene glycol precipitation, phenol extraction and isopropanol precipitation. This method was compared to other DNA extraction methods with regard to DNA purity and size.

Journal Article↗

PubMed1998

Different reactivity against HCV proteins (RIBA 3) according to progression of liver damage.

BACKGROUND: Aim of the study was to assess the correlation between clinical stage of HCV-related liver disease and viraemia to immune response to different viral antigens. METHODS: We considered 1330 patients with HCV chronic infection followed up from 6 months up to 6 years divided into two groups according to RIBA 3 (Abbott) response: Group I, 1231 patients with positivity for at least two bands (83 subjects with asymptomatic infection, 941 with chronic hepatitis, 201 with cirrhosis and 6 with HCC); Group II, 99 patients with positivity at only one band (45 with asymptomatic infection, 53 with chronic hepatitis and 1 cirrhotic). RESULTS: We noticed a major percentage of positive patients for at least three bands in more severe clinical forms (90% of chronic hepatitis or cirrhosis versus 60% of asymptomatics, p < 0.005, chi 2 test). Moreover we noticed a percentage increase of positivity for antibodies anti-c100 and anti-NS5 with the progression of liver damage, statistically significant differences between asymptomatics and patients with chronic forms. We also observed that viraemia is related neither to clinical stage nor to different reactivity to RIBA 3, albeit viraemia is usually detected more frequently among patients with liver damage, but unrelated to different reactivities. CONCLUSIONS: Our results show a clear correlation between number of reactivities towards HCV proteins and progression of liver damage, pointing out that immune response plays a direct role in the long-term outcome of HCV infection.

Aged↗

PubMed1997

PCR amplification of crude microbial DNA extracted from soil.

A rapid, inexpensive, large-scale DNA extraction method involving minimal purification has been developed that is applicable to various soil types. DNA was extracted from 100 g of soil using direct lysis with glass beads and sodium dodecyl sulphate (SDS) followed by polyethylene glycol precipitation, potassium acetate precipitation, phenol extraction and isopropanol precipitation. The crude extract could be used in PCR directed at high-copy number (bacterial small subunit rRNA) and single-copy (fungal beta-tubulin) genes.

Base Sequence↗

PubMed1992

Cytokine activity after allogeneic bone marrow transplantation. IV. Production of mRNA for IL-3 and GM-CSF by mitogen-stimulated circulating mononuclear cells.

The ability of circulating mononuclear cells from recipients of HLA identical sibling marrow transplants to generate messenger (m) RNA for the haemopoietic growth factors interleukin-3 (IL-3) and granulocyte-macrophage colony-stimulating factor (GM-CSF) upon mitogen stimulation was investigated. The amount of IL-3 mRNA per ml of blood and IL-3 mRNA per 10(7) mononuclear cells as well as the amount of GM-CSF mRNA per ml of blood was significantly lower in transplant recipients than in normal volunteers. Lower values for mRNA expression for both IL-3 and GM-CSF were associated with the use of immunosuppressive therapy post transplant. No correlation was found between the expression of message for either cytokine, or the presence or absence of acute graft-versus-host disease at the time of testing. While there was no correlation between the quantity of GM-CSF message produced and time elapsed post transplant, IL-3 message expression increased slightly with increasing time post transplant. These defects of haemopoietic regulators constitute another parameter of impaired cellular immunity occurring after allogeneic marrow transplantation.

Bone Marrow Transplantation↗