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Biomedical subjects

A Canova

Publications and source records attributed to A Canova.

At least 19 recordsLinked to original sources
PubMed2002

Cytokeratin 7 and 20 staining for the diagnosis of lung and colorectal adenocarcinoma.

The origin of metastatic adenocarcinoma lesions can sometimes be difficult to diagnose. The objectives of our study were to establish the cytokeratin staining pattern of primary and metastatic lung and colorectal adenocarcinomas, and to determine if this helps to identify the site of origin of metastatic lesions. We reviewed a total of 102 tissue samples from patients in our tumour registry, with either primary or metastatic lung or colorectal adenocarcinoma. Tissue sections were stained for cytokeratin 7 and 20 and read as positive or negative for staining. Clinical and radiologic information was reviewed from computerised charts. The cytokeratin 7+/cytokeratin 20- pattern characterised 96% (29 out of 30) of primary and 95% (21 out of 22) of metastatic lung adenocarcinomas. All the primary (26), and 88% (21 out of 24) of metastatic colorectal adenocarcinomas stained cytokeratin 7-/cytokeratin 20+. Samples from a variety of metastatic sites were evaluated for cytokeratin 7 and 20 staining. Out of the 102 samples, in 95% (97 out of 102) of the cases, the cytokeratin 7 and cytokeratin 20 staining pattern characterised and differentiated between lung and colorectal adenocarcinoma. Primary and metastatic lung adenocarcinomas show a cytokeratin 7+/cytokeratin 20- staining pattern, while colorectal adenocarcinomas stain cytokeratin 7-/cytokeratin 20+. Cytokeratin staining is helpful in the diagnostic differentiation of metastatic lesions from these two common primaries, and assists in determining the site of origin of metastatic lesions.

Adenocarcinoma↗
PubMed2000

Differentiation of monocytes to macrophages switches the Mycobacterium tuberculosis effect on HIV-1 replication from stimulation to inhibition: modulation of interferon response and CCAAT/enhancer binding protein beta expression.

HIV-1 replication is inhibited in uninflamed lung macrophages and is stimulated during tuberculosis. Attempts to recapitulate activation of HIV-1 replication in primary monocytes and macrophages ex vivo and in the untreated and PMA-treated THP-1 cell line model in vitro have produced opposite results depending on the state of differentiation of the cells. After infection with Mycobacterium tuberculosis, monocytes enhanced HIV-1 replication and produced a stimulatory 37-kDa CCAAT/enhancer binding protein beta (C/EBPbeta) transcription factor, whereas macrophages suppressed HIV-1 replication and produced an inhibitory 16-kDa C/EBPbeta transcription factor. IFN-beta induced inhibitory 16-kDa C/EBPbeta in macrophages, but had no effect on C/EBPbeta expression in monocytes. Macrophages, but not monocytes, were able to activate IFN-stimulated gene factor-3 (ISGF-3), a transcription factor composed of STAT-1, STAT-2, and IFN regulatory factor (IRF)-9, after infection with M. tuberculosis or stimulation with type I IFN. Macrophages expressed IRF-9 DNA-binding activity, but monocytes did not, and addition of the IRF-9 component reconstituted ISGF-3 in extracts of IFN-treated monocytes. Modulation of IFN responsiveness upon differentiation occurred at least in part through a post-transcriptionally regulated increase in IRF-9 expression. Both monocytes and macrophages maintained IFN responsiveness, activating STAT-1 homodimer formation and transcription of the STAT-1 gene after IFN stimulation. In addition, both monocytes and macrophages were able to activate NF-kappaB upon infection with M. tuberculosis. These results show that induction of ISGF-3, expression of the inhibitory 16-kDa C/EBPbeta, and suppression of HIV-1 replication via a transcriptional mechanism are macrophage-specific responses to infection with M. tuberculosis.

CCAAT-Enhancer-Binding Proteins↗
PubMed1996

[Home enteral nutrition in pediatric age. Based on the Torino experience].

Enteral nutrition is increasingly used in the management of sick children. Malnutrition may frequently complicate chronic illness in children and nutritional support may be a primary treatment. Particularly children with malnutrition due to certain chronic disorders may need long term enteral nutrition not only in hospital but also at home. We report our experience on home enteral nutrition of 14 patients, aged from 3 months to 15 years. Eleven had a serious weight deficit (< 3 degrees percentile), but none had severe alteration of the biohumoral nutritional parameters. The indication for EN were: in 7 patients cerebral palsy, in 2 cystic fibrosis, and in the other 5 patients congenital heart disease, multiple food intolerance, oesophageal athresia, Werding-Hoffman disease, Costello's Syndrome. Nutritional support was given by nasogastric tube in 6 patients, through gastrostomy in 3 patients and by mouth in 5 patients. We did not see any severe complication due to home enteral nutrition. The practicalities of this nutritional approach are discussed. Although home enteral nutrition was evaluated in a low number of patients, it may have a role in promoting growth of children with inadequate dietary intake or malnutrition and in improving their quality of life.

Adolescent↗
PubMed1995

Improved method for polyamine determination in TMV, a rod-shaped virus.

Polyamines were measured in viruses using different techniques. An improved method of polyamine analysis is reported for tobacco mosaic virus (TMV), a rod-shaped virus (95% protein and 5% RNA), based on HPLC of sonicated PCA-treated highly purified virus suspensions. This method allowed higher and more reliable recovery of TMV polyamines (putrescine, spermidine and spermine) when compared to the HPLC of non-sonicated samples and to thin layer chromatography. It is suggested that sonication acts on PCA-precipitated protein aggregates causing the release of trapped polyamine molecules.

Chromatography, High Pressure Liquid↗
PubMed1994

Tyrosine phosphorylated p91 binds to a single element in the ISGF2/IRF-1 promoter to mediate induction by IFN alpha and IFN gamma, and is likely to autoregulate the p91 gene.

ISGF2 was initially identified, purified and cloned as an interferon-alpha (IFN alpha) induced transcription factor that binds to the IFN-stimulated response element (ISRE) of IFN alpha/beta-stimulated genes (ISGs). It was reported to be transcriptionally regulated by several cytokines including IFN alpha and IFN gamma. IFN alpha and IFN gamma inducibility is mediated by a single element: a high affinity, nearly palindromic version of the IFN gamma activation site (GAS). The ISGF2 GAS is bound specifically by p91, which was previously identified as a subunit of the ISG activator ISGF3, and shown to mediate IFN gamma induction of the GBP gene via a GAS. Tyrosine phosphorylation and DNA binding activity of p91 parallel transcription of ISGF2 in response to IFN alpha and/or IFN gamma, consistent with induction mediated by only a GAS. Transcription of the genes that encode p91 and p113, another subunit of ISGF3, is activated only by IFN alpha. This result suggests induction mediated by an ISRE, and implies autoregulation, requiring the products of both genes. Specificity of the ISRE is the basis for the previous conclusion. In contrast, it appears likely that the ISGF2 GAS, and p91 or related factors, also mediate induction of ISGF2 by IL-6 and prolactin. Convergence of signalling pathways from at least four cytokines on this single site would thus be a key aspect of a general role for ISGF2 in cellular growth control.

Alternative Splicing↗
PubMed1992

Lateral interactions within color mechanisms in simultaneous induced contrast.

The perceived color of a region of visual space is a function not only of the spectral composition of the light incident from it, but also depends on the light incident from surrounding regions. The color contrast induced into a region is a result of lateral interactions between neural mechanisms. These interactions were studied by measuring the induced effect of circularly symmetric spatial sine-waves on a circular central test region. The phase of the surrounding sine-waves was changed uniformly in time, inducing a modulation in the appearance of the test. Observers adjusted the amplitude of real sinusoidal modulation in the test in order to null the induced modulation, and the nulling modulation was used as a measure of the induced effect. Spatial additivity was tested by using pairs of sine-waves of distinct spatial frequencies. The results showed that brightness induction can be characterized as a linear spatial process, i.e. the effects of parts of the surround at different distances from the test are summed, after the effect of each part is weighted by a negative exponential as a function of distance from the test. The magnitude of pure chromatic induction, however, is a result of nonlinear spatial interactions. Thus, these results have implications for the connections between visual mechanisms that process brightness and chromatic contrast.

Color Perception↗
PubMed1991

Intraperitoneal injections of nanogram CCK-8 doses inhibit feeding in rats.

The satiating effect of intraperitoneal injections of synthetic cholecystokinin octapeptide (CCK-8) was tested in non-deprived and 17 h-deprived male and female Sprague-Dawley rats that were maintained on pelleted diet and offered evaporated milk test meals. At the midpoint of the 12-h diurnal period, 40-160 ng/kg CCK-8 elicited a dose-related decrease in meal size. At midnight, CCK-8's threshold for inhibiting feeding was increased to 80-160 ng/kg in nondeprived and deprived rats, respectively. These doses are 25-50 times less than typically required to significantly decrease food intake after intraperitoneal injection. No CCK-8 dose stimulated nocturnal feeding and no consistent sex difference was observed in CCK-8's effect. Intraperitoneal injection of ng amounts of CCK-8 may mimic a paracrine action of endogenous gut cholecystokinin to signal satiety.

Animals↗
PubMed1990

Chromosomal aberrations, sister chromatid exchanges, and urinary thioethers in nurses handling antineoplastic drugs.

In this study we examined the structural chromosomal aberrations (CA) and sister chromatid exchanges (SCE) of 12 nurses handling moderate quantities of antineoplastic drugs. Urinary thioethers were also measured to assess the potential exposure to alkylating drugs. Two control groups with similar mean age and smoking habits and working in the same hospital were also studied: 1) control clerks and 2) control nurses. Our study did not show any clear increase of chromosomal damage in exposed nurses as compared to controls. However, CA in control nurses were significantly increased (p = 0.05) with respect to control clerks. The results of baseline urinary excretion of thioethers were statistically higher (p less than 0.02) in exposed subjects than in control clerks.

Antineoplastic Agents↗
PubMed1990

Evaluation of chromosomal aberrations in lymphocytes and micronuclei in lymphocytes, oral mucosa and hair root cells of patients under antiblastic therapy.

In 7 patients undergoing antiblastic chemotherapy for the first time, the structural chromosomal aberration (CA) test in peripheral lymphocytes was compared with the micronucleus (Mn) test in lymphocytes, in oral cavity cells and in hair root cells of the scalp. The last test is being proposed for the first time. The CA and Mn frequencies induced by chemotherapy were compared with the baseline (pretreatment) frequencies of the patients and with confidence limits calculated in 4 control groups studied for CA, Mn in lymphocytes, Mn in oral cavity cells and Mn in hair root cells, respectively. The studied chemotherapies induced a clear cytogenetic effect in at least 2 of the tests studied with the exception of interferon-alpha 2b (patient 6) and interferon + low doses of cis-platinum (patient 2) which did not appear to cause evident chromosomal damage. The response to chemotherapy is generally characterized by an increase in Ca and Mn, reaching a peak value and then decreasing in the following weeks. The CA test proves to be the most sensitive despite the fact that CA were analyzed in an average of 100 cells per sample against the 500-3000 cells analyzed for Mn. The efficiency of Mn to detect CA is in the following order: Mn in lymphocytes greater than Mn in buccal cells greater than Mn in hair root cells. The last test appears to be very promising but, used following the current method, does not appear suitable to monitor acute exposure.

Adult↗
PubMed1989

Chromosomal alterations in peripheral blood lymphocytes, urinary mutagenicity and excretion of polycyclic aromatic hydrocarbons in six psoriatic patients undergoing coal tar therapy.

Six male non-smoking subjects treated for psoriasis with topical applications of pure coal tar or 4% coal tar-containing ointment were examined in order to assess the genotoxic risk associated with this type of therapy. Mutagenicity in urine samples collected before and during the coal tar therapy was evaluated in the plate incorporation assay on Salmonella typhimurium strain TA98 in the presence of S9 mix and beta-glucuronidase. Total urinary polycyclic aromatic hydrocarbon (PAH) levels were evaluated in parallel by high resolution gas chromatography/mass spectrometry. In addition, sister chromatid exchanges and chromosomal aberrations were also analysed in peripheral blood lymphocytes collected before, during and after the end of the coal tar applications. The results suggest that urinary mutagenicity levels as well as the frequencies of chromosome aberrations and sister chromatid exchanges in lymphocytes are related to the levels of exposure to coal tar. Moreover the kinetics of repair of chromosome damage in relation to different exposure levels and the capacity of the urinary mutagenicity assay to correctly identify the exposure to significant levels of PAH are discussed.

Administration, Topical↗
PubMed1987

[Usefulness and side effects of a diet rich in vegetable fiber in insulin-dependent diabetic adolescents].

The influence on metabolic control and the possible side effects of a diet rich in vegetable fibers was evaluated in a group of insulin-dependent diabetic adolescents. After two weeks of controlled diet, a new dietary regime with a higher vegetable fiber content (66 g/day vs 15 g/day) and an increased iron content (22.5 mg/day vs 11.5 mg/day) was assigned to each patient for a period of two months. At the end of the dietary trial, a decrease of the insulin requirement, of the mean daily blood glucose values, and of glycosylated haemoglobin (HbA1) was observed. Serum iron levels were statistically lowered, but still in the normal range. These data suggest that high fiber diet can improve metabolic control of type I diabetes, but cast some doubts because of possible side effects on intestinal absorption of oligo-elements.

Adolescent↗
PubMed1985

Therapeutic approach to the Pancoast pain syndrome.

The incidence of the Pancoast syndrome ranges from 2 to 5% of patients with lung cancer. We treated 20 cases between 1979 and 1984 with 29 procedures including percutaneous cordotomy, selective posterior radiculotomy, decompressive laminectomy, central administration of opiates, and TENS. Selective posterior radiculotomy gave the best pain relief.

Buprenorphine↗