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Biomedical subjects

A Arena

Publications and source records attributed to A Arena.

At least 55 records · Page 3Linked to original sources
PubMed1990

T cells do not mediate the initial suppression of a Salmonella infection in the RES.

The course of a sublethal salmonella infection was followed in mice rendered susceptible by irradiation, reconstituted with T-cell-depleted bone marrow from normal donors and given a synergistic pool of CD4 and CD8 monoclonal antibodies. The results indicate that the host response causing the early plateau and suppression of bacterial growth at the end of the first week of the infection, which is essential for survival, does not require T cells.

Animals↗
PubMed1989

Modulation of macrophage functions by corynebacterium parvum preparations.

Corynebacterium parvum has been used as an anti-tumor agent in both animal experiments and clinical trials; nevertheless it is not well established the mechanism of action, since both T-dependent and T-independent ways of action have been proposed. On the other hand, mononuclear phagocytic system activation cannot be ruled out in the immunomodulation carried out by C. parvum. In the attempt to better understand the effects of C. parvum on macrophage functions, experiments were carried out on tumor-bearing rats with a decline of peritoneal macrophage activities as a result of the tumor development. For this purpose three different preparations of C. parvum were investigated: a) the first preparation was obtained by heat-inactivation of bacteria at 60 degrees C for 1h; b) the second by formalin-treatment of bacteria; c) the third obtained from Burrough Wellcome as a formaline-killed suspension in 0.01% w/v thiomersal saline. Each preparation was used at 7 mg/ml dry weight and administered subcutaneously, three days after tumor grafting. The results showed that all three preparations were capable to hinder the tumor mass growth. Macrophage functions as phagocytosis, intracellular killing, intrinsic and extrinsic anti-Herpes Simplex Virus activities, were restored to normal values by each of the preparations used. Nevertheless, concerning the chemotactic activity a discrepancy was noted among the three preparations, since the heat-inactivated one was able to carried out a complete restoration.

Adjuvants, Immunologic↗
PubMed1989

Role of Salmonella enteritidis lipopolysaccharide on anti-HSV activity of macrophages from different anatomical sites.

It is generally agreed that endotoxins from Gram-negative bacteria play a modulatory role on several macrophage functions. The intrinsic activity versus herpes simplex virus type 1 and type 2 of Kupffer cells, peritoneal and alveolar macrophages, harvested from normal and tumour-bearing rats, was evaluated. Moreover, the effects of different intravenous treatments with S. enteritidis endotoxin were investigated. The antiviral activity of peritoneal, alveolar macrophages and Kupffer cells from tumour-bearing rats is definitely impaired but it appears to be positively modulated by in-vivo administration of S. enteritidis lipopolysaccharide (LPS).

Animals↗
PubMed1988

Evaluation of macrophage antiviral activity in patients affected by neoplasia.

The intrinsic antiviral activity of macrophages has been studied in healthy donors and in patients affected by breast cancer and melanoma. In vitro differentiated macrophages from blood-derived monocytes were infected with measles virus, herpes simplex virus type 2 and adenovirus 17. The challenge was carried out with different multiplicities of infection and the synthesis of virus was tested by evaluating the single cycle growth curve in 24 h. The results obtained show that the restriction of virus infectivity by macrophages is strongly influenced by the multiplicity of infection. This was particularly evident with the adenovirus 17. Moreover, macrophages from patients with melanoma and breast cancer showed an impairment of the intrinsic antiviral activity in comparison with normal subjects.

Adenoviruses, Human↗
PubMed1988

Influence of sera from patients affected by neoplasia on some human macrophage functions.

It has been repeatedly reported that several functions of mononuclear cells are impaired in patients affected by neoplasia. Moreover, inhibitory activity of serum and tumor extracts on macrophages have been described. In a previous study, we found a marked impairment of the intrinsic antiviral activity of macrophages derived from monocytes isolated from peripheral blood of patients with breast carcinoma or melanoma compared with that from blood of normal subjects. The aim of the present work was to study whether this impairment was due to circulating inhibitory factors. Macrophages were differentiated in vitro in sera from patients with neoplasia and in sera from healthy donors and then challenged with herpes simplex virus type 2 (HSV-2). Macrophages from normal subjects, incubated with sera from patients, were significantly impaired in their intrinsic antiviral activity. These results support the possibility that circulating inhibitory factors influence the functionality of mononuclear phagocytes in the tumor-bearing host.

Adult↗
PubMed1987

Urinary desipramine hydroxylation index and steady-state plasma concentrations of imipramine and desipramine.

An index of desipramine (DMI) hydroxylation, calculated as the ratio between the amounts of DMI and 2-hydroxydesipramine (2-OH-DMI) excreted in urine after 25 mg orally, was determined in 16 depressed patients. The index varied almost 100-fold between the patients and correlated significantly to the steady-state plasma concentrations of DMI (rs = 0.85; p less than 0.01) but not to the plasma levels of imipramine (IMI) when the patients were treated with 75 mg of IMI daily. Eleven of the 16 patients were subsequently treated with DMI and a significant relationship was again found between the plasma levels of DMI and the urinary DMI-hydroxylation index (rs = 0.87; p less than 0.01). The latter may be utilized in therapeutic drug monitoring to identify individuals with unusually rapid or slow hydroxylation of DMI.

Adult↗
PubMed1986

Amyotrophic choreoacanthocytosis: is it really a very rare disease?

Amyotrophic choreoacanthocytosis (ACA) is a hereditary disease characterized by adult onset, hyperkinesias (with tongue and/or lip biting), neurogenic muscular atrophies, acanthocytosis and normal blood lipoprotein pattern. In this paper we cite 8 patients belonging to three families, describing 6 patients of two of the families. We query the supposed rarity of the disease.

Acanthocytes↗
PubMed1986

Amyotrophic choreo-acanthocytosis: a new observation in southern Europe.

Amyotrophic choreo-acanthocytosis is a rare disease of adult onset characterized by dyskinesias, neurogenic muscular atrophy, erythrocytary acanthocytosis with normal serum lipoproteins and elevated levels of serum CPK. Presumably, this disorder is an autosomal recessively inherited trait. This disease has been described in Japanese, English, Finnish and Puerto Rican people. This is the first observation in the southern countries of Europe, in two members of a Calabrian family. The authors point out that amyotrophic features can occur several years before the appearance of the extrapyramidal disorders.

Acanthocytes↗
PubMed1985

The restoration of impaired macrophage functions using as immunomodulator the Corynebacterium granulosum-derived P40 fraction.

Many microorganisms and compounds of microbial origin exhibit immunomodulatory activities and have been extensively used in immunotherapy of experimental animal tumors and in patients with neoplasia. In this paper we describe the effect of the C. granulosum-derived P40 fraction on the growth and metastatization of the transplantable epithelioma T8 of Guèrin. Moreover, we evaluated the effect of P40 treatment on several depressed macrophage functions of tumor-bearing rats. In particular, the phagocytic and chemotactic activities of such cells were studied, as well as the antiviral intrinsic and extrinsic activities against HSV-1 and the anti-Toxoplasma gondii activity. All these functions were depressed in untreated tumor-bearing rats. Administration of a single intravenous injection of P40 fraction led to the restoration of all depressed macrophage activities to normal values. In particular, the possibility of restoring the antimicrobial activity of macrophages from tumor-bearing rats by treatment with this immunomodulator is of great concern when one considers the increasing incidence of opportunistic infections in immunocompromised hosts. Results are discussed in terms of both the possible mechanism of action of P40 and of its possible target cells.

Adjuvants, Immunologic↗
PubMed1984

T cell-macrophage interaction in arginase-mediated resistance to herpes simplex virus.

Peritoneal macrophages activated by-products derived from a herpes simplex virus-specific helper T cell clone were used to investigate intrinsic and extrinsic resistance mechanisms to herpes simplex virus type 1 infection in vitro. T cell-activated macrophages produced fewer infective centres, indicating enhanced intrinsic resistance, and markedly reduced the growth of virus in a permissive cell line. The reduction in virus growth correlated with the depletion of arginine in the support medium, presumably resulting from increased arginase production by activated macrophages. The significance of these findings for antiviral immunity in vivo is discussed.

Animals↗
PubMed1983

Tumor-dependent resistance of rat peritoneal macrophages to herpes simplex virus.

By their position at sites of initial infection and their wide distribution in major organs of the body, macrophages may be decisive in determining the susceptibility or resistance of the host to virus infection. Macrophage restriction of virus replication has been shown to be closely related to virus strains or virus types and to the age of the infected host. We report the effects of the development of a solid tumor in rats on intrinsic in vitro macrophage activity against herpes simplex virus type 1. The results obtained with the infectious center assays and the analysis of single-cycle growth curves of herpes simplex virus type 1 in macrophages obtained from normal and tumor-bearing rats showed a depression of antiviral activity of macrophages from tumor-bearing rats. The possibility of immunomodulation by bacterial adjuvants on tumor-bearing rats and the effects on the antiviral activity of peritoneal macrophages were furthermore demonstrated.

Adjuvants, Immunologic↗
PubMed1982

Structure-activity relationships of new antiviral compounds.

In preliminary experiments, the compound 2-amino-5-(2-sulfamoylphenyl)-1,3,4-thiadiazole (G413) was shown to possess high activity against DNA viruses (herpes simplex viruses 1 and 2 and adenovirus 17) and RNA viruses (poliovirus 1, echovirus 2, and coxsackievirus B4). Experiments on the replicative cycle of poliovirus 1 and production of infectious RNA viruses demonstrate that this compound probably prevents assembly of virus particles by acting on structural proteins. In the present experiments, results concerning the activity of derivatives of G413 after side-chain modification are reported. Modification of the primary amine H to CH3 or CH2-CH = CH2 produced a loss of activity against DNA viruses, but inhibitory action on RNA viruses was preserved. Modification to CH2CH3 resulted in the loss of antiviral activity.

Antiviral Agents↗
PubMedDate not supplied

Morphologic variations in bacteria under stress conditions: near-field optical studies.

The morphologic and structural variations suffered by cells of a population of Pseudomonas aeruginosa ATCC 27853 under stress conditions were investigated by using scanning near-field optical microscopy. The analysis of the images, supported by microbiological data, showed that the bacteria evolved from the initial distribution of rod-shaped cells of standard size to a population with structural and morphologic modifications. The detection of variations in the optical reflectivity over a subwavelength scale (< or = 100 nm), combined with the concurrently acquired topographical signal, allowed the visualisation of rod-shaped bacteria going towards a lytic process and entire "U"-shaped cells. In the latter cells, which derived from a morphology refolding of rod bacteria, cellular matter seemed to rearrange itself to attain a coccoid stress resistant form, responsible for the residual viability of the population.

Biomass↗