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Biomedical subjects

A Plaza

Publications and source records attributed to A Plaza.

At least 37 records · Page 2Linked to original sources
PubMed1992

Differential interleukin secretion by in vitro activated human CD45RA and CD45RO CD4+ T cell subsets.

The CD45RA and CD45RO isoforms have been reported to define complementary subsets among CD4+ T cells: CD45RA CD4+ T cells are considered "virgin T cells" and CD45RO "primed T cells." We investigated the secretion of lymphokines by human CD4+ CD45RO and CD4+ CD45RA T helper cells after mitogen stimulation. CD45RA and CD45RO CD4+ T cells were isolated by negative immunoselection using magnetic beads. CD45RO cells, but not CD45RA cells, proliferate well in response to pokeweed mitogen (PWM) or insoluble anti-CD3. Both subpopulations produced interleukin (IL)-2, IL-6, and interferon (IFN)-gamma when stimulated with PWM for 1-4 days. Only Day 1 supernatants from CD45RO cells contained moderate amounts of IL-4. After 14 days of continuous culture and stimulation with PWM, the CD45RA subset had lost the expression of CD45RA and gained that of CD45RO. When long-term cultured CD45RA or CD45RO cells were treated with insoluble anti-CD3, they incorporated [3H]thymidine at similar levels, but only CD45RO cells secreted IL-4 and significantly increased their secretion of IFN-gamma. These data indicate that despite phenotype conversion, the two subpopulations maintain functional differences in the secretion of lymphokines, thus suggesting that circulating CD45RA and CD45RO cells may represent different lines of differentiation.

Antigens, CD↗
PubMed1991

New human V beta genes and polymorphic variants.

To extend the characterization of the human V beta gene repertoire, we utilized anchored or V beta-specific polymerase chain reaction to generate a large (approximately 200 clones) beta-chain library from the thymus of a single individual. Nine new V beta genes were identified, including single members for two new subfamilies (V beta 22 and 23), two new members of the V beta 5 subfamily, and one new member each for V beta 2, 6, 7, 9, and 12. Full-length sequences were also obtained for the published partial sequences of V beta 3, 5.3, 9.1, and 13.4, and additional nucleotides for V beta 7.1 and V beta 7.2. Based on consensus sequences from multiple clones, apparent allelic variants for six V beta genes (V beta 2.1, 5.3, 7.2, 8.2, 13.4, and 16) were also tentatively identified. Population and family studies for two of these (V beta 2.1 and 16) further confirmed that these V beta were alleles and not separate genes. Nonconservative substitutions in some of these alleles, as well as in previously identified alleles, are located at the hypervariable loops or the framework region. These findings indicate that V beta gene polymorphism appears to be significant in humans and might be the result of selective pressure imposed by conventional Ag (hypervariable loops) or superantigens (framework regions).

Amino Acid Sequence↗
PubMed1990

Coding sequence polymorphisms among V beta T cell receptor genes.

The four V beta gene segments, V beta 1, 3.1, 6, and 10, which previously have been shown by RFLP analyses to differ between TCR V beta a and V beta b haplotypes, were cloned and sequenced from V beta a SWR mice and compared with V beta b strains to define coding sequence polymorphisms distinguishing these haplotypes. V beta 3.1 and 6 alleles differed between strains by a single amino acid, whereas V beta 1 and 10 alleles differed by 4 and 6 amino acids, respectively. The overall interhaplotypic V beta polymorphisms appeared to be limited when based upon compilation of this information and previously published V beta sequences. One application of these data was to attempt to elucidate the molecular basis underlying the recently reported allele-specific autoimmune disease, collagen-induced arthritis. Based on the present structural data and the additional evidence, contrary to what was suggested, the V beta 6 gene does not appear to be the sole participant in anticollagen responses.

Amino Acid Sequence↗
PubMed1986

[Treatment of acute crises of bronchial asthma in children using subcutaneous salbutamol as an alternative to adrenaline: comparative study].

A prospective study has been made in order to asses the efficacy of subcutaneous salbutamol as acute treatment for asthmatic crisis, comparing the results with those of adrenaline. The series consisted of 30 cases, divided into two groups according to the administered treatment, with ages ranging between 5 to 18 years. Once the clinical examination and spirometric measurements were made the first group was treated with subcutaneous adrenaline 0.1 cc/kg (max.; 0.5 cc), while the second was treated with subcutaneous salbutamol 20 micrograms/kg (max.: 500 micrograms). A clinical and spirometric examination was performed at 15, 30, 60 and 90 minutes. A similar increase in FEV1 was observed in the two groups at 15 minutes, maintaining this increase for 90 minutes in the group treated with salbutamol and decreasing in the group treated with adrenaline, being the difference statistically significant (p less than 0.001). In view of this results it seems advisable to administer subcutaneous salbutamol as urgent treatment for an acute asthmatic crisis.

Adolescent↗
PubMed1983

In vitro immune cell function in six cases of immunoproliferative small intestinal disease after long term remission.

We have studied several parameters of in vitro immune cell function in peripheral blood mononuclear cells from six patients with immunoproliferative small intestinal disease after long term remission. We have observed two groups of patients with different patterns of response. (a) After stimulation with pokeweed mitogen (PWM) and Staphylococcus aureus, three patients showed a significant reduction of the Ig synthesis (A, G and M) and the proliferative response. In two of them, we found increased spontaneous suppressor T cell activity. In the third case, the diminished response could not be attributed, according to our assays, either to suppressor T cells, lack of T helper activity (although the number of OKT4+ cells was diminished) or an intrinsic B cell defect. The three patients showed normal or augmented NK activity and an inversion of the OKT4+/OKT8+ ratio was detected in two of them. (b) The remaining three patients showed a normal Ig synthesis after stimulation with PWM and a slightly depressed IgM synthesis in response to S. aureus. They expressed a normal T helper cell function and did not show increased spontaneous suppressor T cell activity. They had low levels of natural killer cytotoxicity and the OKT4+/OKT8+ ratio was not significantly altered. Taken together, our data indicate that significant alterations of the in vitro immune response can be found in peripheral blood mononuclear cells of some immunoproliferative small intestinal disease patients after long term remission.

Adult↗
PubMed1982

Alkaline phosphatase activity as a membrane marker for activated B cells.

Alkaline phosphatase activity was assayed by a microtiter assay (with p-nitrophenylphosphate used as substrate) in the plasma membrane of mouse spleen cells activated in vitro by the B cell mitogen LPS and the T cell-dependent B cell mitogen, PWM. No activity was detected in spleen cells cultured in the presence of the T cell mitogens PHA and Con A. This alkaline phosphatase activity was detected in the blast-enriched 30 to 40% fraction of discontinuous Percoll gradients in LPS-treated cultures, and the enzymatic activity assayed was susceptible to inhibition by the alkaline phosphatase inhibitors EDTA and L-phenylalanine. These data support the idea that the membrane alkaline phosphatase activity could be used as a marker for activated B cells.

Alkaline Phosphatase↗
PubMed1981

Rotavirus infection in children hospitalized for diarrhoea in Argentina.

An epidemiological survey was undertaken to establish the importance of rotavirus as a cause of admission of children to hospital in Buenos Aires, Argentina. Between August 1978 and January 1980 rotavirus infection was detected in 62 (34%) of 180 infants and children admitted to hospital with acute gastro-enteritis. In identification of the virus, electron microscopy (EM) was found to be as sensitive as counterimmunoelectrophoresis (CIE). There was agreement between EM and CIE diagnosis in 90.5% cases. Adenovirus and coronavirus were detected by electron microscopy less often. A serological response to rotavirus was revealed by complement fixation test in 38 (72%) of 53 infected patients. Rotaviruses were detected throughout the year, but peak incidence occurred during the cooler months, May to August. Infection was commoner among children under six months of age. Diarrhoea was generally mild in these children and respiratory illness showed no significant association with rotavirus gastroenteritis. These results indicate that rotaviruses may be a major cause of infantile acute gastroenteritis in Buenos Aires, Argentina especially during the winter.

Argentina↗
PubMedDate not supplied

[Analysis of 83 bronchospasm episodes seen at urgent care during one spring night].

BACKGROUND: The new treatments for the bronchial inflammation in asthma, have contributed to decrease the mortality rate. However, there is still a group of population with no diagnosis fo asthma, who requires urgent medical attention in situations such as air pollution or risen pollen levels. On 2nd June 2000, 83 subjects with an acute crisis of asthma, came to the Emergency Room in our Hospital in just 6 hours, coinciding with the highest annual pollen measurement and a strong storm. METHODS AND RESULTS: Personal data from those 83 patients, medical behaviour at the Casualty and post-attention recommendations were considered for analysis. 21 % never had previous diagnosis of asthma and 93 % followed no regular medical control. 61.45 % did no treatment. A chest radiography was taken in 53.76 % of the patients. Salbutamol was administrated in most of them (92.18 %) and parentally administration of steroids in 23.47 %. 21 % were referred to an specialist. CONCLUSIONS: A significant rate of asthmatics is under-diagnosed, under-controlled and under-treated. Public Health authorities should consider the creation of new Allergy Units, a fluid communication between general practitioners and specialists, and the monitorization of pollen recounts with special plans of emergency situations to contribute to solve this problem.

Adrenal Cortex Hormones↗
PubMedDate not supplied

[Recurrent angioedema and hypereosinophilia].

INTRODUCTION: Among the various causes of eosinophilia are the syndrome first described by Gleich in 1984. This syndrome is characterized by angioedema of the face, neck, extremities and trunk, weight gain, hypereosinophilia (60-70%), fever, and increased serum IgM levels without involvement of the vital organs. CASE REPORT: A 17-year-old non-allergic woman was referred to our hospital for further investigation of recurrent angioedema, initially of the hands and feet and subsequently of the face, with onset 3 years previously. The attacks had become more frequent and severe and had occurred monthly in the previous year. The patient also showed general malaise, without fever. Complementary investigations revealed eosinophils 40.8%, total count 3,300/mm3, and serum IgM levels 343 mg/dl (normal range: 53-300 mg/dl). Possible causes of hypereosinophilia and eosinophilic infiltration of vital organs were ruled out. The patient was treated with oral corticosteroids which produced clinical remission and reduction of eosinophil count (1.7%, total 200/mm3). DISCUSSION: Gleich syndrome is uncommon and has well-defined clinical features and a benign course. We describe a patient who presented the clinical characteristics of this syndrome with good response to steroids and without involvement of vital organs. CONCLUSIONS: Our patient presented clinical features compatible with a diagnosis of Gleich syndrome. Other entities associated with hypereosinophilia were ruled out.

Adolescent↗
PubMedDate not supplied

Desensitization to azathioprine.

Azathioprine is an immunosuppressant drug which is an analog to 6-mercaptopurine and has been used in the last 20 years to prevent organ transplant rejection. It has also been used in the treatment of some autoimmunological diseases. We present a case of a 24-year-old woman with systemic lupus erythematosus, suffering from nephritis, who developed angioedema after using azathioprine to control her illness. She had never reported similar episodes. The involvement of the drug was demonstrated by positive oral challenge test without changes in biochemical and complement blood determinations. She reached tolerance to the drug after a desensitization procedure (increasing 5 mg each day to reach 125 mg daily). We are not able to propose the involvement of an IgE-mediated mechanism, but rather a hypersensitive one with a non-dose-dependent effect. These desensitization procedures show great potential as therapeutic safeguards against harmful drugs in some patients. We have not found any other desensitization procedure for this drug.

Adult↗