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Biomedical subjects

R Vaccaro

Publications and source records attributed to R Vaccaro.

At least 37 records · Page 2Linked to original sources
PubMed1995

Cromolyn versus nedocromil: duration of action in exercise-induced asthma in children.

Cromolyn sodium (10 mg), nedocromil sodium (4 mg), and placebo, all delivered by a metered dose inhaler, were compared in their efficacy and duration of action in preventing exercise-induced asthma in children. After a screening test was performed, 13 patients with asthma performed standard exercise tests 20 minutes and 140 minutes after drug inhalation in a randomized, double-blind, crossover study. Both drugs were significantly more protective than placebo after 20 minutes, but no significant difference was seen between cromolyn sodium and nedocromil sodium. No difference between active drugs and placebo was found 140 minutes after inhalation. At these clinically recommended doses both cromolyn sodium and nedocromil sodium provide equal protection against exercise-induced asthma, and the duration of action of both lasts for less than 2 hours.

Adolescent↗
PubMed1995

T lymphocytes bearing the gamma delta T cell receptor are susceptible to steroid-induced programmed cell death.

The mechanisms by which glucocorticoids suppress immune responses have not yet been clearly defined. In steroid-sensitive pathological conditions, an increase in gamma delta T cells can occur in certain untreated systemic autoimmune disorders and seems to be a peristent feature in most cases of systemic lupus erythematosus (SLE). Our previously published data demonstrated that immunosuppressive therapy normalized this expanded SLE T cell subset in parallel with clinical remission of the symptoms. To establish how corticosteroid treatment determines the disappearance of peripheral blood gamma delta T lymphocytes, circulating alpha beta and gamma delta T lymphocytes from seven SLE subjects with active disease and seven healthy individuals were cultured in the presence or absence of 10(-7) M Dexamethasone (DEX). Cell suspensions were then analysed for DNA fragmentation, characteristic of apoptotic cell death, by a new cytofluorimetric method. Conventional agarose-gel electrophoresis on the same T cell populations was carried out for comparison. Regular follow-ups for 6 months revealed in vivo steroid treatment determined a dramatic fall in SLE blood gamma delta T cells, and in vitro experiments seem to indicate that DEX-triggered apoptotic signals are confined to the double negative (CD4-CD8-) gamma delta T cell subpopulation which disappears after in vivo immunosuppressive therapy. Clinical and pathological remission of some autoimmune diseases is often obtained by corticosteroids. Our results offer new insights on the mechanisms through these hormones exert their potent inhibitory activities on immune system cells postulated to play a role in the generation of autoimmune responses.

Adult↗
PubMed1995

Gamma delta T-cell subset distribution in human semen from fertile donors.

PROBLEM: Gamma delta T-cell subset distribution has not been fully investigated in normal human semen. METHODS: We therefore carried out experiments by using a direct immunofluorescence staining technique followed by two-color cytofluorimetric analysis on mononuclear cell (MC) suspensions from ejaculates of ten healthy, fertile volunteers. Autologous peripheral blood MC were simultaneously analyzed and the results used for statistical comparison. RESULTS: The proportion of normal human semen lymphocytes bearing the gamma delta T-cell receptor for antigen was greatly increased compared with autologous circulating counterparts. Interestingly, the rise was mainly due to an overexpansion of cells expressing V delta 1 gene-encoded determinants on their surface. This contrasts with the normal blood picture, where most gamma delta T cells express V delta 2 conformational epitopes. CONCLUSIONS: The numerical and phenotypical differences in semen gamma delta T lymphocytes provide further evidence of a defined migrating lymphocyte subset balance in anatomically and physiologically distinct areas of the body. Their functional role, in terms of both helper and suppressor-cytotoxic activities in the nonsterile proximal portions of the male genital tract, now needs to be explored in detail.

Adult↗
PubMed1995

Gamma delta T lymphocytes in mumps meningitis patients.

Flowcytometric analysis on T-cell subpopulations in the blood and cerebrospinal fluid (CSF) of 10 children with mumps meningitis (MM) revealed that the proportion of lymphocytes which bore the gamma delta T-cell receptor for antigen was significantly higher in CSF than in autologous and heterologous blood samples. gamma delta T-cell values in CSF of MM patients were also significantly higher than those calculated in CSF specimens from nine children with non-inflammatory neurological disorders. Whether and how the expanded CSF gamma delta T-lymphocyte subset, either CD8+ or double-negative (CD4-/CD8-), contributes to the eradication of mumps virus infection from the central nervous system represents a central focus of our ongoing research.

Antigens, CD↗
PubMed1995

Peripheral blood gamma delta T cells in human listeriosis.

A phenotypical analysis carried out by direct immunofluorescence and two-colour cytofluorometry showed that the number of lymphocytes bearing the gamma delta T-cell receptor heterodimer was increased in the blood of eight children with Listeria monocytogenes infection, mainly due to an expansion of cells identified by monoclonal antibodies which recognize V delta 2 gene products. These findings are further evidence that gamma delta T cells are in some way involved in the immune response directed against human intracellular pathogens.

Female↗
PubMed1994

Comparison of the protective effects of cromolyn sodium and nedocromil sodium in the treatment of exercise-induced asthma in children.

Seventeen children with asthma were studied in a double-blind, crossover, placebo-controlled study designed to compare the efficacy of cromolyn sodium with that of nedocromil sodium in preventing exercise-induced asthma. All drugs were delivered through a metered-dose inhaler (cromolyn sodium, 10 mg; nedocromil sodium, 4 mg; placebo, two puffs). Nedocromil sodium and cromolyn sodium provided significant, comparable protection from exercise-induced asthma, and both drugs were better than placebo. We conclude that nedocromil sodium and cromolyn sodium administered by a pressurized aerosol provide equal protection against exercise-induced asthma in children.

Adolescent↗
PubMed1993

Lymphocytes bearing the gamma delta T cell receptor in acute Brucella melitensis infection.

A phenotypical analysis carried out by indirect immunofluorescence and two-color cytofluorometry showed that the number of lymphocytes bearing the gamma delta T cell receptor (TcR) heterodimer was dramatically increased in the blood of six children with Brucella melitensis infection. Most in vivo expanded gamma delta T cells reacted with a monoclonal antibody which identifies V delta 2 gene products and a significant proportion expressed CD25 and HLA-DR activation antigens. In addition, whereas only a few gamma delta T lymphocytes were CD8+, nearly all were CD4-. Highly enriched populations of both alpha beta and gamma delta T cells were obtained by negative immunoselection from three subjects with brucellosis sampled during convalescence. Despite the different form of their TcR, the proliferation of these two major T cell subsets in response to a mitogenic anti-CD3 monoclonal reagent (OKT3) was optimal. In contrast, alpha beta, but not gamma delta, T lymphocytes proliferated vigorously in response to the antigenic stimulus elicited by heat-killed Brucella. Further studies are, therefore, needed to determine whether the selective expansion of the gamma delta T cell subpopulation observed during the clinical course of the infection is driven by antigenic determinant(s) borne by the pathogen in vivo or is due to host-derived stimuli, such as autologous heat-shock proteins expressed on the surface of the infected cells.

Acute Disease↗
PubMed1992

Oral bile acid treatment and the patient with Zellweger syndrome.

The cerebrohepatorenal syndrome of Zellweger is a congenital syndrome of multiple manifestations, including hepatomegaly and liver dysfunction. Treatment is generally of a supportive nature, aimed at improving nutrition and growth, controlling the central nervous system symptoms and limiting progression of liver disease. Because the liver disease in Zellweger syndrome may be attributed to an overproduction and accumulation of cholestanoic acids, exacerbated by diminished primary bile acid synthesis, we hypothesized that primary bile acid administration would be beneficial in improving liver function by a mechanism involving down-regulation in the synthesis of these atypical bile acids. We report here the clinical and biochemical responses to primary bile acid administration in a 2-mo-old boy who was seen with the typical signs of Zellweger syndrome. Liver disease was evident from hepatomegaly and elevated serum liver enzymes and bilirubin. The diagnosis was supported by markedly elevated serum very long chain fatty acids and the bile acids dihydroxycholestanoic acid and trihydroxycholestanoic acid. Confirmation of the lack of peroxisomes was established by electron microscopy. When the patient was 6 mo old, the primary bile acids cholic acid and chenodeoxycholic acid, (100 mg each/day) were administered orally. A significant improvement in biochemical indices of liver function occurred with a normalization of the serum bilirubin and liver enzymes and a histological improvement in the extent of inflammation and bile duct proliferation and disappearance of cannalicular plugs. Serum and urinary cholestanoic acids showed a significant decrease within a few days. A striking and sustained increase in growth was observed after therapy, and an improvement in neurological symptoms was noted. In conclusion, this study indicates that primary bile acid therapy improves liver function and growth in the patient with peroxisomal dysfunction and should be considered in the supportive therapies for this condition.

Administration, Oral↗
PubMed1992

Lymphocytes bearing the gamma/delta T-cell receptors in Down's syndrome.

Subjects with Down's syndrome (DS), or trisomy 21, have an increased susceptibility to infections, malignant diseases and autoimmune phenomena. Various arms of the immune system are severely impaired in trisomic patients. We found that the proportion of blood lymphocytes bearing the gamma/delta T-cell receptor (TCR) was significantly higher in adults with trisomy 21 than in age- and sex-matched healthy controls. Interestingly, the increase was mainly due to an over-expansion of cells which bear non-covalently bound gamma/delta chains on their surface. This contrasts with the normal blood picture, where the great majority of gamma/delta T cells express the disulphide-linked form of the TCR. The fact that trisomic gamma/delta T cells are both numerically and phenotypically unbalanced provides further evidence that immunological abnormalities are integral features of DS.

Adult↗
PubMed1992

Modification of lectin binding in rat gut mucosa during experimental cholestasis.

Glycoconjugate distribution on rat gut mucosa has been studied by using peroxidase-labelled lectins (Lotus tetragonolobus, Dolichos biflorus, Arachis hypogaea and Glycine max) after surgical interruption of the common bile duct. Specimens from cholestatic rats were compared with sham-operated (simple laparotomy) and normal controls to determine which of the observed modifications could be due either to the operation itself or to the cholestasis. Most of the modifications occurred in the duodenum. The operation itself modified some binding properties. Lotus tetragonolobus binding extended both in cholestatic and in sham-operated rats, but returned to normal levels earlier in sham-operated than in cholestatic rats. Conversely, cholestasis induced (1) almost total loss of Arachis hypogaea binding in the Golgi zone of superficial duodenal goblet cells; (2) an increase at the 14th postoperative day of Dolichos biflorus binding in the cytoplasmic calyx of goblet cells which then diminished up until the 28th day; and (3) an increase of Glycine max binding in the Golgi zone of goblet cells.

Animals↗
PubMed1992

Lymphocytes bearing the gamma delta T-cell receptor in acute toxoplasmosis.

Although the relative and absolute numbers of CD3+ cells (T lymphocytes) were similar in eight children with acquired Toxoplasma gondii infection and 10 uninfected age- and sex-matched healthy controls, the proportion of cells bearing the gamma delta T-cell receptor was significantly higher in the subjects with acute toxoplasmosis. The great majority of gamma delta T cells from the infected patients expressed covalently bound gamma delta chains on their surface, i.e. were BB3+ lymphocytes. Since the gamma delta T-cell subsets exert both restricted and unrestricted major histocompatibility complex cytotoxicity, further research is needed to elucidate the role of gamma delta T cells in the control of this coccidian protozoan infection.

Acute Disease↗
PubMed1991

Extremely thermostable glutamate dehydrogenase from the hyperthermophilic archaebacterium Pyrococcus furiosus.

The hyperthermophilic archaebacterium Pyrococcus furiosus contains high levels of NAD(P)-dependent glutamate dehydrogenase activity. The enzyme could be involved in the first step of nitrogen metabolism, catalyzing the conversion of 2-oxoglutarate and ammonia to glutamate. The enzyme, purified to homogeneity, is a hexamer of 290 kDa (subunit mass 48 kDa). Isoelectric-focusing analysis of the purified enzyme showed a pI of 4.5. The enzyme shows strict specificity for 2-oxoglutarate and L-glutamate but utilizes both NADH and NADPH as cofactors. The purified enzyme reveals an outstanding thermal stability (the half-life for thermal inactivation at 100 degrees C was 12 h), totally independent of enzyme concentration. P. furiosus glutamate dehydrogenase represents 20% of the total protein; this elevated concentration raises questions about the roles of this enzyme in the metabolism of P. furiosus.

Amino Acids↗