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Biomedical subjects

C López

Publications and source records attributed to C López.

At least 109 records · Page 6Linked to original sources
PubMed1997

Characterization of allergens from Trisetum paniceum pollen: an important aeroallergen in Mediterranean continental climatic areas.

BACKGROUND: Trisetum paniceum is a grass plant which is characteristic of a Mediterranean continental climate and has been described as one of the major causes of type I allergy in the Madrid region. OBJECTIVES: To identify and characterize the allergens of Trisetum paniceum pollen. METHODS: Allergenic extracts were prepared by 24 h incubation of pollens in a buffered solution. Proteins were analysed by a new two-dimensional system in which agarose plates were used for isoelectric focusing. Two-dimensionally resolved proteins were electrically transferred to Immobilon membranes and the allergens immunochemically detected. Proteins from six grass pollens were bound to a membrane and incubated with a pool of serum from grass-pollen-sensitized patients. The bound IgE antibodies were then eluted and used to identify the proteins of Trisetum paniceum pollen that allergenically crossreact with allergens from other pollen grasses. RESULTS: Relative to total protein content, Trisetum paniceum pollen had a high proportion of reactive proteins. On the basis of their molecular characteristics, allergens could be classified as group 1, 2, 4 and 5 components yet included an atypical proportion of basic components. All identified allergens were crossreactive with allergens from the remaining grass pollens studied. CONCLUSIONS: Trisetum paniceum pollen contains a high proportion of allergens and these include a group of basic proteins which are not detected in other phylogenetically related pollens and could be of allergological interest.

Air Pollutants↗
PubMed1997

[Sanitary conditions of community dining halls in greater Buenos Aires, Argentina].

Because of the importance of food safety for public health, a study was done to determine the microbiologic quality of foods provided to patrons of community dining halls in greater Buenos Aires, Argentina. The study was descriptive and was conducted in three municipalities with intermediate or high poverty indices; a sample of 52 dining halls was selected randomly from those municipalities. Information was collected from April 1994 through April 1995 by means of surveys, direct observations, and microbiologic analyses of the water and food served. Water and food analysis followed the recommendations of the Argentine Food Code and the International Commission on Microbiologic Specifications for Foods, respectively. The results were interpreted according to the values for cooked foods agreed upon by the Working Group on Food Monitoring. The microbiologic analysis revealed that 28 (54%) of the dining halls had food or water of inadequate quality and 11 (21%) had inadequacies in both. Bacillus cereus was the most commonly found pathogenic bacterium in the food samples analyzed. The factors that were significantly associated with unsatisfactory microbiologic conditions in the food and water were lack of disinfection of the water (P = 0.009), lack of hygiene in the environment (P = 0.03), the presence of rodents and insects (P = 0.05), the supply system for raw materials (P = 0.01), and a relatively small number of users, i.e., fewer than 100 (P = 0.0008). It was concluded that water disinfection and general clean-up of the dining halls were measures that could be put in place by providing education in the areas of hygiene and food handling to supervisors and employees. The results obtained also indicate the need to include a food safety evaluation among the general evaluation criteria for food assistance programs.

Adolescent↗
PubMed1996

Age-related differences in the glomerular and renal tubular effects of amikacin in the rat.

Several biological responses to drugs are dependent on the age of the individual. Renal excretion of amikacin occurs mainly through glomerular filtration and this function is diminished in the young animal. We evaluated the renal response to amikacin in the unanesthetized infant rat (21-day-old) and we compared it with that of the adult rat. Either amikacin (7.5 and 75.0 mg/kg body weight, i.m.) or vehicle were administered to infant rats and the effects on sodium, potassium and water balance were assessed. Creatinine clearance (Ccr) was calculated. Amikacin induced an increment in sodium absolute excretion, whereas the Ccr decreased. In the infant rat the effects were more marked. Changes in FENa were more marked than those in Ccr, suggesting a direct effect of amikacin on the tubular reabsorption of electrolytes in addition to deleterious effects on glomerular dynamics. Our results suggest that amikacin induces more changes in renal function in the infant than in the adult rat and therefore it might be convenient to carefully evaluate the renal condition in the patients that receive this drug.

Aging↗
PubMed1995

MDM2 expression in lymphoid cells and reactive and neoplastic lymphoid tissue. Comparative study with p53 expression.

MDM2 and p53 immunohistochemical protein expression was analysed in lymphocytes and in reactive and neoplastic lymphoid tissue. Phytohaemagglutinin (PHA)-stimulated lymphocytes displayed MDM2 and p53 co-expression. In 8 of 8 tonsils, 24 of 24 Hodgkin's disease (HD), and 10 of 24 high-grade non-Hodgkin's lymphoma (HG-NHL) specimens, MDM2 paralleled p53 nuclear expression in non-tumour and tumour cells. The number of positive cells was greater and the staining intensity was stronger for p53 than for MDM2. In another nine of the 24 HG-NHL cases studied, dissociated expression was observed, with high p53 expression and very low or absent MDM2 expression. In five cases, both MDM2 and p53 were negative. The eight low-grade NHL (LG-NHL) cases were also MDM2- and p53-negative. MDM2 and p53 expression in PHA-activated lymphocytes and reactive lymphoid tissue is probably an expression of opposing biological signals regulating cell proliferation. Parallel MDM2 and p53 expression in all HD and in 10 out of 24 HG/NHL cases may indicate that this growth suppressive pathway is maintained in those cases. However, dissociated MDM2/p53 expression (nine cases) and the absence of expression of both proteins (five cases) may represent examples of deregulation of this growth control pathway. These findings are in agreement with previous in vitro studies in cell lines regarding the role of MDM2/p53 lymphoid tissue, suggesting a possible role for MDM2 deregulation in lymphomagenesis.

Blotting, Western↗
PubMed1995

Editing of the chloroplast ndhB encoded transcript shows divergence between closely related members of the grass family (Poaceae).

The ndhB-encoded transcript from barley chloroplasts deviates from the genomic ndhB sequence by nine C-to-U transitions, which is the maximum number of editing events for a chloroplast mRNA reported so far. Comparison with ndhB transcripts from other chloroplast species shows that six of the nine editing sites observed in barley are structurally and functionally conserved in maize, rice and tobacco. The remaining three sites, however, show divergent patterns of conservation even within the three members of the grass family. The conservation of two of these sites in tobacco but not in the closely related graminean species suggests that divergence of the ndhB editing sites is caused by the loss of preexisting editing sites rather than by gain of new sites.

Amino Acid Sequence↗
PubMed1995

Role of protein kinase C on the acute desensitization of renal cortical adenylate cyclase to parathyroid hormone.

The mechanisms of adenylate cyclase desensitization to parathyroid hormone are still unclear. Current evidence suggest that the signal generated after PTH binding to receptors results in activation of adenylate cyclase and stimulation of phospholipase C with subsequent activation of protein kinase C. Recent studies have suggested a role of protein kinase C on the regulation of the PTH-dependent receptor-adenylate cyclase system in cultured cells. Therefore, the present studies were conducted to examine the role of protein kinase C on the desensitization of canine renal cortical adenylate cyclase after an acute exposure in vivo to PTH. A group of normal dogs were treated with a single intravenous injection of 1 microgram/k of syn bPTH (1-34) or Nle bPTH (3-34). Ten minutes later, animals were subjected to bilateral nephrectomy and the kidney cortex processed for preparations of basolateral membranes for determinations of adenylate cyclase activity, as well as membrane and cytosolic fractions for analysis of protein kinase C activity. Animals not treated with PTH were used as controls. PTH administration in vivo resulted in a 46.9 +/- 9.3% decrease in maximal adenylate cyclase activity in vitro in response to syn bPTH (1-34) (P < 0.001). Likewise, PTH binding as measured with 125I-Nle8,18,Tyr34-bPTH (1-34)NH2 showed a 40 +/- 3% decrease. This alterations were associated with a marked translocation of protein kinase C from the cytosol to the membrane. Thus, protein kinase C activity in membrane fractions increased from 160.6 +/- 44.8 pmol Pi/min in controls to 500.4 +/- 123 in PTH treated dogs (P < 0.03).(ABSTRACT TRUNCATED AT 250 WORDS)

Adenylyl Cyclases↗
PubMed1994

[Non Hodgkin lymphoma of the stomach: evaluation of surgical treatment in 24 patients].

This is a retrospective review of 24 patients with Non Hodgkin Lymphoma of the stomach operated between 1959 and 1991. The diagnosis was reached with a radiological study in 12 of 15 (80%) patients and with endoscopy in 11 of 16 (69%) of patients. Eleven of 14 (78%) preoperative biopsies available at the moment of the revision were positive for non Hodgkin Lymphoma. Clinical staging was performed using Ann Arbor Classification and the histological type was defined according to the Working Formulation. Diffuse large cell lymphoma (intermediate grade) was the most frequent histological subtype. Eleven patients were in clinical stage I, 10 patients in stage II and 3 in stage IV. Eight total gastrectomies and 16 subtotal gastrectomies were performed. Twenty one percent of patients had a postoperative complication and operative mortality was 12%. Stage I patients were treated exclusively with surgery and no recurrences were observed. Stage II patients received adjuvant chemotherapy, the tumor recurred in three and two died due to disease progression. Five years disease free survival was 64%. It is concluded that surgical treatment achieves a good disease control in stage I patients but must be complemented with chemotherapy in stage II tumors.

Actuarial Analysis↗
PubMed1994

[Child physical punishment: opinions of the children from 2 schools].

To measure the proportion, reasons and frequency of battering and punishment, we surveyed seventh and eight grade children coming from a low and middle income area, state funded school (n = 84) and from a payed, private and catholic school (n = 98). Of children coming from the payed school, 67% lived with both parents and battering was more intensely rejected, compared to 85% of children coming from the state funded school. The most frequent type of punishments were admotions and restrictions; limb pulling and shaking at the payed school whereas hand and belt battering at the state funded school were the most frequent types of physical punishment. Eighty six percent of children coming from the state funded school and 54% coming from the payed school admitted having been battered. The mother was the leading user of battering for 87% of children at the state funded school and for 77% of children at the payed school; the figures for the father were 36 and 68% respectively. Lack of academical performance, defiance and running away from home were the principal justifications for punishment at the state funded school; defiance and sexual relations were so at the payed school. It is concluded that the frequency of battering is related to the social environment and that its eradication is difficult since 26% of children considered it as an acceptable rearing method.

Adolescent↗
PubMed1993

Lung function and bronchial response to methacholine in young adults who had asthma in childhood.

Lung function and bronchial response to methacholine were studied in 47 young adults who had had childhood asthma, and after a period of 14-21 years, showed a different clinical evolution. At present, these subjects have been classified in four clinical groups: asymptomatic, rhinitic, asthmatic only due to exercise, and asthmatic. The same study was performed in 23 healthy individuals without personal histories of respiratory or allergic pathology. We found low spirometric basal values in both the asthmatic group (FEV1 and FEF25-75) and in the group with asthmatic responses to exercise (FEF25-75). No significant differences were found among asymptomatic, rhinitic, and control groups. While airway hyperreactivity was observed in patients who still had asthma, the bronchial response to methacholine in asymptomatic and rhinitic groups was not different from the control group. We conclude that both lung function and bronchial response to methacholine in most of the adults who had asthma in infancy and had been without asthmatic symptoms for many years are similar to those observed in the general population.

Adolescent↗