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Biomedical subjects

G Cavallo

Publications and source records attributed to G Cavallo.

At least 127 records · Page 7Linked to original sources
PubMedDate not supplied

Interferon-gamma plays a crucial role in T lymphocyte reaction against alloantigens.

In this study we report that addition to mixed lymphocyte reactions of monoclonal antibodies to interferon-gamma inhibits alloantigen recognition and induction of cytotoxic T lymphocytes by inducing early and highly effective suppressor T lymphocytes. This inhibitory activity is not confined to in vitro models, since daily local injection of these antibodies in CBA/J mice blocks the rejection of fully allogeneic tumor cells consistently displayed by untreated CBA/J mice.

Animals↗
PubMedDate not supplied

External beam radiation therapy to prevent postangioplasty dialysis access restenosis: a feasibility study.

PURPOSE: To evaluate the feasibility and short-term side-effects of postangioplasty external beam radiation for patients with compromised arteriovenous dialysis accesses. MATERIALS AND METHODS: Ten patients with compromised arteriovenous dialysis accesses were studied. Following confirmation of access compromise by an angiogram, patients were treated by a standard angioplasty +/- stent deployment. The target volume incorporated a margin of 1 cm beyond the angioplastied segment. The first 5 patients were treated to a dose of 12 Gy in two 6-Gy fractions spaced 48 h apart, whereas the next 5 patients were treated to 8 Gy in two similarly separated 4-Gy fractions. Five of the patients had at least one prior access that had failed. The current access had been in use for 6-52 months, and 5 of the 10 patients had at least one episode of compromise involving the current access. The length of stenosis ranged from 2 to 9 cm (mean 4.4 cm). All patients were followed clinically for adequacy of dialysis; a radiological follow-up with a fistulogram was performed for all in 3-monthly intervals. Follow-up ranged from 4 to 10 months, with a median follow-up of 6 months. RESULTS: There were no procedure-related complications. Three patients developed a restenosis at the site of the original stenosis, and one patient developed a restenosis at the edge of the stent. As part of the natural history of this process, five patients have also developed new lesions elsewhere in the proximal veins requiring radiological intervention. None of the patients showed any radiation-related side effects, either in the skin/ soft tissues, or in the vasculature on follow-up angiograms. CONCLUSIONS: Several different radiotherapeutic approaches are being currently investigated to prevent postangioplasty restenosis. There are several issues involved with the use of endovascular brachytherapy in these patients. On the other hand, given the superficial location of the dialysis access, we believe that external beam radiation offers a safe and simple method of radiation therapy in this setting. The clinical efficacy of this modality needs to be established through a randomized phase III trial.

Adult↗
PubMedDate not supplied

Different mechanisms regulate the IFN-inducible expression of 40 kDa human 2'-5' oligo (A) synthetase in HeLa and Molt 4 cells.

Expression of 40 kDa 2'-5' oligo (A) synthetase can serve as a marker of interferon (IFN) activity on the biological target. The mechanisms of induction of human 40 kDa 2'-5' oligo (A) synthetase by IFNs were investigated in HeLa and Molt 4 cells. Using a combined treatment with cycloheximide and actinomycin D we observed that in HeLa cells IFN-alpha did not need ongoing protein synthesis to induce the enzyme, whereas the addition of cycloheximide prevented the induction by IFN-gamma. IFN-alpha induced the 40 kD enzyme in the T-cell line Molt 4 to a level comparable to that in HeLa cells, but only in the presence of active protein synthesis. These results suggest that an early response gene coding for a positive IFN-inducible protein may be needed in T cells, but not in HeLa cells to regulate the transcription of this 2'-5' oligo (A) synthetase gene.

2',5'-Oligoadenylate Synthetase↗
PubMedDate not supplied

The effect of pre-treatment of syngeneic mice with tumour cells cultured in vitro on the induction of a transplantable tumour.

The pre-treatment with in vitro cultured mammary adenocarcinoma (ADK-1t) cells strongly protects syngeneic Balb/c mice against the challenge with the same non-cultured tumour cells. If the cultured cells were detached with sodium versenate, 50-60% protection was given, whereas if trypsin was used only 20-30% protection was achieved. That in vitro culture considerably reduces the oncogenic potential of ADK-1t cells was shown by the fact that very many more cultured than non-cultured cells were required to induce tumours.

Adenocarcinoma↗
PubMedDate not supplied

Enhancement of tumour growth by pretreatment with tumoral cells adsorbed by poly i:c deae-dextran complex in syngeneic mice.

Pretreatment of balb/c mice with ADK-1t cells adsorbed with Poly I:C DEAE- dx complex was found to enhance tumour growth as measured after challenge with non adsorbed ADK-1t cells. This results contrasts strongly with the increased tumour resistance previously observed when Poly I:C alone was used for adsorption. Some reasons are suggested for this striking difference.

Animals↗
PubMedDate not supplied

[Synergism of dicloxacillin and broad-spectrum penicillins].

On the basis of the proved protective activity showed by isoxazolyl penicillins on other antibiotics, a comparative study about the action of dicloxacillin over four penicillins with a broad spectrum was carried on. Either the experiments "in vitro" (antibacterial activity, growth dynamics, determination of beta-lactamase inactivation) then those "in vivo" have proved a real protection. A comparative study on different associations was also performed.

Bacteria↗
PubMedDate not supplied

The murine IFN-gamma receptor does not transduce the activation signal to a murine promoter in human cells.

MuIFN-gamma receptor cDNA has been stably transfected in the human WISH cell line. A stable transfectant, denominated WISH-C2, expressed 46;000 receptors/cell whose affinity was similar to that observed on murine cells (Kd = 2.6 x 10(-9) M). When WISH-C2 cells were treated with Hu- or MuIFN-gamma, antiviral and antiproliferative activities were observed with HuIFN-gamma only. These findings suggest that other species-specific components associated to the binding site are required for the signal transduction. To overcome the complexity of measuring biological functions that very likely involve more than one regulatory and structural gene, we set up for the first time a system where a reporter gene driven by a murine promoter was used to directly evaluate the interaction of MuIFN-gamma receptor with an inducible promoter through the missing transducer factor.

Animals↗
PubMedDate not supplied

[Gastrointestinal angiodysplasia. Clinical, endoscopic, angiographic and histologic study].

The authors report 10 cases of gastrointestinal bleeding angiodysplasia (4 male and 6 female). The surgical treatment was normally provided and the main clinical features, were observed by radiological, endoscopic and pathological findings. Angiodysplasia was observed in the colon (4 cases), in the small intestine (3 cases) and in the stomach (3 cases). Common symptoms (bleeding and sideropenic anaemia), where possible associated with endoscopic and angiographic study, permitted to determine diagnosis and lesion's extension. Pathological findings showed that vascular dilatation wasn't present only in the mucosa and in the submucosa, as in the amartomatous congenital forms, but was present in all intestinal wall, as in the secondary forms, more frequent.

Adult↗
PubMedDate not supplied

Cancer and environment.

The attention of scientists has been directed mostly to analyze the influence of the environment on tumor induction. However, the external environment can also enhance the reactivity of the host organism towards tumors, by activating several immune mechanisms. Moreover, the host organism is the first "foreign" environment with which tumor cells come into contact in a dynamic way, characterized by a continuous evolution.

Animals↗
PubMedDate not supplied

Regulation of gene expression by interferons.

IFNs are a family of proteins produced by various cells following stimulation by biological or synthetic inducers. The interaction with the membrane receptor is followed by the activation of the expression of particular genes that are responsible for their antiviral, antiproliferative and immunomodulatory properties. Initiation of transcription is an early and critical event in the control of eukaryotic gene expression. In this review we will briefly discuss the mechanisms exploited by IFNs to control at transcriptional level the expression of inducible genes. In particular we will focus on some characteristics if cis-acting DNA elements that are located upstream from the initiation site for RNA transcription and of nuclear trans-acting factors that are required for modulation of gene expression by IFNs.

Animals↗
PubMedDate not supplied

Characterization of the nuclear factors involved in 202 gene induction by IFN-alpha in NIH-3T3 cells.

When treated with IFN-alpha, NIH-3T3 cells express after a few hours high levels of the mouse 202 gene mRNA. This activation takes place at the transcriptional level as shown by nuclear "run on" assay. For this purpose a fragment of 806 base-pairs (the b fragment), spanning the 5'-flanking region of the 202 gene, was linked to the reporter CAT gene and transiently transfected into mouse NIH 3T3. The data suggest that the b fragment is sufficient to confer transcriptional inducibility upon IFN stimulation and can account in large part for the response of the 202 gene. Binding assays, using a 40-bp probe derived from the IFN-stimulated response element (ISRE) comprised in the b fragment, demonstrated the presence of two DNA-binding proteins. One of these, defined as complex A, was inducible upon IFN treatment, whereas the other, defined as complex B, was constitutively present regardless of IFN treatment. The IFN-alpha-induced complex A appears to have the necessary characteristics to be the transcriptional activator of the 202 gene: it requires the same nucleotides for binding as are required for IFN-dependent gene activation and is dependent on IFN-alpha treatment.

Animals↗