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Biomedical subjects

G Cappelli

Publications and source records attributed to G Cappelli.

At least 19 recordsLinked to original sources
PubMed2006

Characterization of drug-resistance mutations in HIV-1 isolates from non-HAART and HAART treated patients in Burkina Faso.

Non-B HIV subtypes have been estimated to account for 88% of HIV infections in the world. These subtypes are particularly relevant in view of the availability of antiretroviral (ARV) drugs, since subtype-specific mutations are associated with drug-resistance in developing countries. Therefore, the pol gene sequences in HIV-1 isolates were examined from the three distinct groups of 39 infected patients from Ouagadougou in Burkina Faso: 17 patients who had not received any antiretroviral therapy (ART); 16 patients received ART, and 6 HIV-infected children, from infected mothers, received a single Nevirapine dose prophylaxis during birth. HIV-1 pol sequencing was successful for 29 samples. As expected, all patients presented the common (non-B subtype) M36I polymorphism and 26/29 (90%) the K20I mutation. Phylogenetic studies showed high predominance of recombinant HIV-1 strains: CRF06_cpx 16/29 (55.17%), CRF02_AG 9/29 (31.03%), A1 2/29 (6.89%), G 1/29 (3.44%), and CRF09_cpx 1/29 (3.44%). Two twins showed, 6 months after birth, a NNRTI-mutation (Y181C/Y). During the same period, the twin mother presented a different NNRTI-mutation (V106I), thus suggesting that the different blood drug concentration may determine a different drug-resistance pathway. Among 17 non-highly active antiretroviral therapy (HAART) patients, 3/17 (17.64%) presented virus with reverse transcriptase (RT) mutations [V118I: 1/17 patients (5.88%), V179E: 2/17 patients (11.76%)]. 10/17 (58.82%) presented virus with minor protease (PR) mutations [L63P: 5/17 patients (29.41%), V77I: 3/17 patients (17.64%), L10I: 2/17 patients (11.76%)]. 4/17 patients did not show any PR and RT mutations (23.52%). Among six HAART-treated patients, 6/6 and 3/6 had M36I and L63LP protease minor subtypes, respectively; and only two (33.33%) presented virus with K103N mutation. The low prevalence of drug-resistant associated mutations in Burkina Faso is encouraging. However, further studies with a larger cohort with a high non-B subtype prevalence are necessary to optimize ART in developing countries.

Adult↗
PubMed2001

Human macrophage gamma interferon decreases gene expression but not replication of Mycobacterium tuberculosis: analysis of the host-pathogen reciprocal influence on transcription in a comparison of strains H37Rv and CMT97.

Mycobacterium tuberculosis is an intracellular pathogen that readily survives and replicates in human macrophages (MPhi). Host cells have developed different mycobactericidal mechanisms, including the production of inflammatory cytokines. The aim of this study was to compare the MPhi response, in terms of cytokine gene expression, to infection with the M. tuberculosis laboratory strain H37Rv and the clinical M. tuberculosis isolate CMT97. Both strains induce the production of interleukin-12 (IL-12) and IL-16 at comparable levels. However, the clinical isolate induces a significantly higher and more prolonged MPhi activation, as shown by reverse transcription-PCR analysis of IL-1beta, IL-6, IL-10, transforming growth factor beta, tumor necrosis factor alpha, and gamma interferon (IFN-gamma) transcripts. Interestingly, when IFN-gamma transcription is high, the number of M. tuberculosis genes expressed decreases and vice versa, whereas no mycobactericidal effect was observed in terms of bacterial growth. Expression of 11 genes was also studied in the two M. tuberculosis strains by infecting resting or activated MPhi and compared to bacterial intracellular survival. In both cases, a peculiar inverse correlation between expression of these genes and multiplication was observed. The number and type of genes expressed by the two strains differed significantly.

Gene Expression Regulation, Bacterial↗
PubMed2001

Tuberculosis and lung cancer. An interesting case study.

This report describes the case of a patient with lung cancer who completely recovered when he was suffering from tuberculosis. Since bacillus Calmette-Guerin (BCG) has beneficial effects in certain types of cancer, it was hypothesized that infection with Mycobacterium tuberculosis induced an effective response against the tumour. M. tuberculosis-infected blood T-lymphocytes of the patient were cultured with two lung tumour cell lines. T-lymphocytes in vitro remained attached to tumour cells that appeared reduced in number. Moreover, M. tuberculosis isolated from the patient was a strong inducer, in infected macrophages, of the expression of the inducible form of the nitric oxide synthase, that may regulate cytotoxic activity of human macrophages.

Aged↗
PubMed2000

Human immunodeficiency virus type 1 infection modulates the interleukin (IL)-1beta and IL-6 responses of human macrophages to CD40 ligand stimulation.

Better understanding of the mechanisms of proinflammatory cytokine production during human immunodeficiency virus (HIV) type 1 infection is of pivotal importance. The effect of HIV-1 infection on recombinant CD40 ligand (CD40L)-induced interleukin (IL)-1beta and IL-6 production by human macrophages was analyzed. ELISA and cytofluorometric analysis demonstrated that CD40L stimulation of HIV-1-infected macrophages resulted in substantial production of IL-1beta and IL-6. In contrast, no cytokine response was observed in uninfected cells. No modulation of the receptor for CD40 was found to account for the enhanced response to CD40L. The CD40L effect was not due to lipopolysaccharide contamination and was completely abrogated by preincubation with a monoclonal anti-CD40L antibody. mRNA studies indicated that the priming effect of HIV-1 on the macrophage response to CD40L was regulated at the transcriptional level. Finally, the effect of HIV-1 on the cytokine response could not be abolished by the HIV-1 protease inhibitor U75875 at concentrations that completely suppressed HIV-1 replication.

Anti-HIV Agents↗
PubMed2000

Mycobacterium tuberculosis H37Rv comparative gene-expression analysis in synthetic medium and human macrophage.

Mycobacteria are intracellular pathogens that survive and grow in host macrophages. Following phagocytosis, sustained intracellular bacterial growth depends on its ability to avoid destruction by macrophage-mediated host defences such as lysosomal enzymes, reactive oxygen and the reactive nitrogen intermediates. This suggests that the interaction between host cell and microbe is delicately balanced, and can be tipped in favour of either organism. The identification of Mycobacterium tuberculosis H37Rv (MTB) genes expressed within host cells would contribute greatly to the development of new strategies to fight tuberculosis. In the present study, we compared MTB gene expression in the course of intra- (human macrophages) and extracellular growth (Sauton's medium) to ascertain whether differences might occur between gene-expression patterns in the two habitats of replication. Using reverse-transcriptase polymerase chain reaction (RT-PCR) on a group of 14 MTB-Complex-specific genes, we found that MT10Sa (a small stable RNA), 35 kDa (unknown), ahpC (alkyl hydroperoxide reductase, AhpC), sigF (alternative RNA Polymerase sigma factor), and katG (catalase-peroxidase, HPI) genes are expressed in both the environments, while Ag85B, Ag85C (members of the Antigen 85 Complex), rpoV (RNA Polymerase sigma factor) and ESAT6 (early secretory antigen, 6 kDa) are expressed only in the in vitro culture; on the other hand, Ag85A (Antigen 85 Complex), rpoB (RNA Polymerase beta sub-unit), pab (Protein antigen b), invA and invB genes (encoding proteins that show homologies with p60 of Listeria monocytogenes) are expressed only inside the macrophage. Positive RT-PCR products on cDNAs for these genomic regions were not obtained from approximately 1000-fold more bacteria grown in Laboratory Broth. Identification of M. tuberculosis genes expressed in response to phagocytosis by human macrophages increases our basic understanding of the host-pathogen interaction, and helps to identify bacterial factors necessary for in vivo survival and growth.

Colony Count, Microbial↗
PubMed2000

Novel splicing and missense mutations in autosomal dominant polycystic kidney disease 1 (PKD1) gene: expression of mutated genes.

Autosomal dominant polycystic kidney disease (ADPKD) is a common disorder mostly characterized by cyst formation in kidney tubules. The majority of ADPKD cases is caused by mutations in the PKD1 gene, but no prevalent mutation has been reported. By heteroduplex analysis of the 3' single-copy region of the gene, we have searched for mutations in subjects from 40 ADPKD families of Northern Italy. Seven novel polymorphisms and three novel disease-associated mutations (R3718Q, L3851P and IVS45+56del25) were identified. Both missense mutations are located in the major extracellular loop of polycystin-1. The 25 bp deletion inside intron 45 did not affect 5' and 3' consensus splicing sites, but caused a 56 nucleotide out of frame-deletion due to activation of a cryptic 3' splice site in exon 46. The mutated RNA should produce a truncated polycystin 1 at the G binding peptide in the intracellular C-terminal end of the protein. RT-PCR analysis showed that the disease-associated mutations were present in transcribed sequences. In particular, RNA analysis of BHK cells transfected with PKD1 genomic DNA, including the deleted intron, showed that no normal transcript is produced by the deleted gene. This intronic mutation, found in a large pedigree, seems to be associated with a prevalence of cerebrovascular disease.

Adult↗
PubMed2000

Biofilms invade nephrology: effects in hemodialysis.

Bacteria attach to surfaces and aggregate in a biopolymer matrix to form biofilm. Studies on biofilm have shown its presence in many prosthetic devices used in nephrology as well as in fluid pathways of hemodialysis plants and monitors. Once present, this community of bacteria increases resistance to biocide due to slime production and, as a result, chemical products for dialysis monitor disinfection and descaling procedures do not result in an effective treatment. Ultrapure dialysate is a goal in modern hemodialysis, and ultrafiltration is used to obtain sterile and apyrogen fluids. Microbial colonisation of ultrafilters may occur if, due to inadequate disinfection protocols, membrane is exposed to persistent bacterial contamination, and biofilm is allowed to form and to grow. As more and more data link final dialysate microbial contamination to clinical effects of bioincompatibility from chronic inflammation in dialysis patients, attention has to be focused on possibilities of biofilm avoidance.

Biofilms↗
PubMed2000

Dialysate flow distribution in hollow fiber hemodialyzers with different dialysate pathway configurations.

UNLABELLED: The efficiency of a hemodialyzer is largely dependent on its ability to facilitate diffusion, since this is the main mechanism by which small solutes are removed. The diffusion process can be impaired if there is a mismatch between blood and dialysate flow distribution in the dialyzer. The objective of the paper was to study the impact of different dialysate compartment designs on dialysate flow distribution and urea clearances. Eighteen hollow fiber 1.3 m2 hemodialyzers were studied, 6 each of 3 designs: Type A--standard fiber bundle (PAN 65DX Asahi Medical, Tokyo, Japan); Type B--spacing filaments external to the fibers (PAN 65SF Asahi Medical, Tokyo, Japan); Type C--fibers waved to give Moiré structure (FB130 Nissho-Nipro, Osaka, Japan). IN VITRO STUDIES: 3 dialyzers of each type were studied following dye injection into the dialysate compartment. Dynamic sequential imaging of longitudinal sections of the dialyzer were undertaken, using a new generation helical CT scanner (X-Press/HS1 Toshiba Corporation, Tokyo, Japan). In vivo studies: 3 dialyzers of each type were studied, in randomized sequence, in 3 different patients under standardized dialysis conditions. Blood- and dialysate-side urea clearances were measured at 30 and 150 minutes of treatment. Macroscopic and densitometrical analysis revealed that flow distribution was most homogeneous in the dialyzer with Moiré structure (Type C) and least homogeneous in the standard dialyzer (Type A). Space yarns (Type B) gave an intermediate dialysate flow distribution. Significantly increased urea clearances (p<0.001) were seen with Types B and C, compared to the standard dialyzer. Type C (Moiré) had the highest clearances although these were not significantly greater than Type B (space yarns). In conclusion, more homogeneous dialysate flow distribution and improved small solute clearances can be achieved by use of spacing yarns or waved (Moiré structure) patterns of fiber packing in the dialyzer. These effects are achieved probably as a result of reduced dialysate channeling resulting in a lower degree of mismatch between blood and dialysate flows. The new radiological technique using the helical CT scanner allows detailed flow distribution analysis and has the potential for testing future modifications to dialyzer design.

Equipment Design↗
PubMed1999

Expression of CCR5 is increased in human monocyte-derived macrophages and alveolar macrophages in the course of in vivo and in vitro Mycobacterium tuberculosis infection.

Human immunodeficiency virus (HIV) replicates more efficiently in Mycobacterium tuberculosis (MTB)-infected macrophages than in uninfected controls. We investigated whether this may be partly explained by changes in expression of CCR5 in the course of mycobacterial infection, as this molecule has been shown to be a coreceptor for HIV entry. Since the lung is the preferential organ of HIV replication in the course of tuberculosis, we preliminarily analyzed beta-chemokine receptor expression in alveolar macrophages from patients with active tuberculosis, using flow cytometry based on an MIP-1alpha ligand-biotin/avidin-FITC detection system. Increased MIP-1alpha receptor (MIP-1alphaR) expression in alveolar macrophages from infected patients was observed whereas no detectable expression could be revealed in uninfected controls. Since MIP-la can also bind CCR1 and CCR4, the presence of CCR5 mRNA was investigated in bronchoalveolar lavage (BAL) cells and detected in alveolar macrophages from tuberculosis patients only. The study was then extended to in vitro MTB-infected macrophages. Monocyte-derived macrophages (MDMs) were left to differentiate for 7 days before MTB H37Rv infection, and CCR5 expression was monitored, by using a specific monoclonal antibody, on days 1, 6, and 11 after infection. Increased CCR5 expression in MTB-infected macrophages was observed, with a peak on day 6 (64% in MTB-infected versus 33% in control cultures) and a decrease by day 11 (25% in MTB infected versus 13% in control cultures). These results show that CCR5 expression is enhanced in the course of in vitro MTB infection and during active pulmonary tuberculosis.

Cells, Cultured↗
PubMed1999

Mutations in autosomal dominant polycystic kidney disease 2 gene: Reduced expression of PKD2 protein in lymphoblastoid cells.

The polycystic kidney disease 2 (PKD2) gene, encoding a 968-amino acid integral membrane protein with six predicted membrane-spanning domains and intracellular NH2 and COOH termini, is mutated in approximately 15% of the cases of autosomal dominant polycystic kidney disease (ADPKD), a common genetic disease frequently resulting in renal failure. For a better understanding of the cause of this disorder, we searched for mutations in the PKD2 gene in two PKD2-linked families characterized by different clinical phenotypes. A common polymorphism, a nonsense mutation, and a frameshift mutation were found. Both mutations are predicted to produce truncated proteins of 314 and 386 amino acids, arrested at the first extracellular loop of the protein. Restriction enzyme analysis of polymerase chain reaction (PCR) and reverse transcriptase (RT)-PCR products, respectively, showed that mutations cosegregated with the disease and mutated alleles were expressed at the messenger RNA level in lymphoblastoid cell lines. However, in these cells, Western blot analysis showed only PKD2 normal protein, and it was expressed at a lower level than that found in cells without the PKD2 mutation. These findings suggest that in lymphoblastoid cells, the truncated protein product of the mutant allele may not be stable.

Aged↗
PubMed1999

Evaluation with breast scintigraphy of breast lesions of indeterminate significance after conventional triple diagnostic approach.

The role of breast scintigraphy in the evaluation of 30 women with an uncertain diagnosis following triple assessment was investigated. Scintigraphy was positive in 7 of 13 cancers and 3 of 17 benign lesions and dubious in 1 of 13 cancers and 2 of 17 benign lesions. Sensitivity ranged from 61.5% to 53.8% depending whether dubious lesions were designated as positive or negative. This study shows that breast scintigraphy is not sufficiently sensitive or specific to use in the evaluation of lesions of uncertain diagnosis following triple assessment.

Journal Article↗
PubMed1999

In vitro and in vivo evaluation of a new polysulfone membrane for hemodialysis. Reference methodology and clinical results. (Part 1: in vitro study).

Different high flux membranes have been recently developed. The present study is aimed at describing the technical features and the clinical performances of a new high flux polysulfone membrane (T-sulfone, Toray, Japan). The study has been carried out on two different dialyzers (surface area = 1.3 and 1.8 m2). The filters have been tested in vitro under definite experimental conditions. The hydraulic flow resistance, the pressure drop in the blood compartment and the hydraulic permeability have been determined in a wide range of in vitro experimental conditions. The in vitro sieving coefficients for various solutes have also been determined utilizing human blood. Hydraulic permeability was found in the range of 28.4 ml/h/mm Hg/m2 and sieving coefficients were between 0.96 and 1.0 for all low molecular weight solutes. The sieving coefficient for inulin was 0.95. The pressure drop in the filter at 300 ml/min of blood flow was 95 mm Hg for the 1.3 m2 and 57 mm Hg for the 1.8 m2. The filters are then designed to operate in the presence of high blood flows without excessive resistance in the blood compartment. The blood compartment analyzed by means of a special radiological sequence obtained with a helical scanner after dye injection confirmed the homogeneous distribution of the blood flow in several cross sections of the bundle. Adequate distribution of dialysate was confirmed with a similar method applied to the dialysate compartment. The new imaging techniques utilized were greatly helpful to determine adequacy of filter design and flows distribution.

Biocompatible Materials↗
PubMed1999

In vitro and in vivo evaluation of a new polysulfone membrane for hemodialysis. Reference methodology and clinical results. (Part. 2: in vivo study).

Different high flux membranes have been recently developed. The present study is aimed at describing the technical features and the clinical performances of a new high flux polysulfone membrane (T-sulfone, Toray, Japan). The study has been carried out on two different dialyzers (surface area = 1.3 and 1.8 m2). The filters have been tested in vivo during hemodialysis and hemodiafiltration. The in vivo study was carried out on 12 ESRD patients on regular hemodialysis treatment. The protocol was reviewed and approved by the local ethical committee. The in vivo clearances (K) at 300 ml/min of blood flow are reported in the following Table: [Table in text]. Beta-2-m reduction ratio exceeded 50% in all sessions. Beta-2-m mass balance executed by collection of spent dialysate and elution from the used filters evidenced that removal is obtained mostly by filtration while absorption is negligible. Excellent tolerance and hemocompatibility was observed in all the studied sessions.

Adsorption↗
PubMed1999

Low concentrations of glucose degradation products in peritoneal dialysis fluids and their impact on biocompatibility parameters: prospective cross-over study with a three-compartment bag.

The side effects of glucose degradation products (GDPs) in conventional peritoneal dialysis (PD) fluids are well described. Using the three-compartment bag concept--that is, in situ preparation of concentrated glucose solution into a standard ionic solution--a GDP-free solution can be processed. To investigate the possible impact of this product on biological and clinical parameters, we carried out a prospective cross-over study with 31 patients, comparing the short-term effects of conventional PD and GDP-free PD solutions. Classical peritoneal parameters and ultrafiltration rate did not change during the study. After three months and after six months with the three-compartment bag, cancer antigen 125 (CA125) concentration in overnight fluid increased significantly (p < 0.001) from 24.4 IU/mL to 44.4 IU/mL and 41.1 IU/mL respectively. CA125 decreased significantly (p < 0.01) to 21.7 IU/mL after three months with the conventional solution. No change in hyaluronan concentration was observed. A slight increase of procollagen III N-terminal peptide in overnight effluent with the GDP-free solution was followed by a significant reduction after three months with standard solution. In summary, our data show that the GDP-free PD fluid improves mesothelial cell mass and turnover even after a short-term period of three months. A better quality of PD solution is obtained by using the three-compartment bag.

Biocompatible Materials↗