In vivo administration of doxazosin in rats highly decreases serum circulating levels of testosterone through a mechanism involving the testicular renin-angiotensin system.

Men are at greater risk of cardiovascular and renal diseases than women. Several hypertensive rat models also exhibit gender differences in blood pressure. Although the mechanisms responsible for these gender differences are not clear, androgens have been shown to promote hypertension. Testosterone is produced by Leydig cells under the regulation of catecholamines acting through both alpha- and beta-adrenoceptors. Some investigators have postulated a putative role of angiotensin II (Ang II) in modulating the action of gonadotropin in Leydig cells, inhibiting testosterone production. In the present work, we analysed the potential mechanism by which the testicular renin-angiotensin system (RAS) decreases the serum circulating levels of testosterone after the in vivo administration of the long-acting selective alpha(1)-adrenergic receptor antagonist doxazosin. RAS was analysed through assessment of the activity of its proteolytic regulatory enzymes. We can conclude that the testicular testosterone production, at least in rat, is regulated by catecholamines through a mechanism involving alpha(1)-adrenergic receptors and RAS, with a putative role for Ang III. Because doxazosin is usually used as a pharmacological therapy in the treatment of hypertension and benign prostatic hyperplasia, our results could also indicate that its benefits are due, at least in part, to decreased serum circulating levels of testosterone.

Modelling diseases: the allergens of Olea europaea pollen.

This study analyzes the influence of the IgE response to certain olive pollen allergens in the modulation of the different clinical phenotypes of allergic disease and their relationship with the level of exposure to pollen and genetic factors. Patients from high-exposure areas had a complex IgE antibody response to allergens of Olea euroapea, which included 3 or more allergens in 75% of cases. The majority allergens were Ole e 1, Ole e 2 (profilin), Ole e 7 (lipid transporting protein), Ole e 9 (glucanase), and Ole e 10. The existence of the antigen HLA-DR2 (15) led to a higher risk of sensitization to Ole e 10 and a greater trend towards the development of severe asthma, which increased in the presence of an anti-profilin IgE. Thirty percent of patients suffering from pollinosis simultaneously presented allergy to vegetable foods. Anti-Ole e 7 IgE was significantly associated with fruit anaphylaxis and anti-profilin IgE was detected in 90% of patients with oral syndrome. Finally, we analyzed the role of glucanase and Ole e 10 as causes of the pollen-latex-fruit syndrome.

Pyrrolidon carboxypeptidase activities in the hypothalamus-pituitary-thyroid and hypothalamus-pituitary-ovary axes of rats with mammary gland cancer induced by N-methyl nitrosourea.

Pyrrolidon carboxypeptidase is an omega-peptidase that hydrolyses N-terminal pyroglutamyl residues from biologically active peptides such as gonadotropin-releasing and thyrotrophin-releasing hormones. We previously described a decrease in both rat and human pyrrolidon carboxypeptidase activity with breast cancer, suggesting that gonadotropin-releasing hormone may be an important local intracrine, autocrine and/or paracrine hormonal factor in the pathogenesis of breast cancer while playing a role in the tumoral process. However, the other susceptible substrate of pyrrolidon carboxypeptidase, thyrotrophin-releasing hormone, may also be modified with breast cancer, supporting an association between breast cancer and thyroid disorders. The present work analyses soluble and membrane-bound pyrrolidon carboxypeptidase activities in the hypothalamus-pituitary-thyroid and hypothalamus-pituitary-ovary axes in N-methyl nitrosourea-induced breast cancer in rats. Our aim was to determine the possible relationship between gonadotropin-releasing hormone and thyrotrophin-releasing hormone regulation through pyrrolidon carboxypeptidase activity. We propose that pyrrolidon carboxypeptidase activity dysregulation at various local and systemic levels may participate in the initiation, promotion and progression of breast cancer induced in rat by N-methyl nitrosourea through the increase in gonadotropin-releasing hormone. Since pyrrolidon carboxypeptidase activity also acts on thyrotrophin-releasing hormone, the dysregulation of this enzyme's activity could indirectly affect hypothalamus-pituitary-thyroid axis function, and thus potentially represent a link between the diseases of thyroid and breast cancer.

Ole e 2 and Ole e 10: new clinical aspects and genetic restrictions in olive pollen allergy.

BACKGROUND: The clinical characteristics in olive pollen allergy are dependent on the antigenic load, the allergens profile, and the genetic restrictions. Our objective was to determine specific response pattern in Ole e 2 and Ole e 10 sensitization at those levels. METHODS: We studied 146 patients with seasonal rhinitis and/or asthma and positive prick test to Olea europaea pollen. IgE against Ole e 2 and Ole e 10 were detected by skin prick test and ELISA. HLA-DRB1 and HLA-DQB1 loci were typed by polymerase chain reaction sequence-specific primers method. RESULTS: A total of 102 (69.9%) and 79 (54.0%) patients showed significant IgE antibody response against Ole e 2 and Ole e 10, respectively. There was a significant association between Ole e 2 (OR 2.2, P = 0.04) and Ole e 10 reactivities (OR 2.8, P = 0.007) with asthma. In addition, total and specific IgE antibody levels significantly correlated with asthma (P < 0.05). Patients who reacted to both allergens reached the highest asthma risk factor (OR 4.3, P = 0.002). Phenotypic frequency of DR7 (OR 5.4, Pc = 0.003) and DQ2 (OR 3.6, Pc = 0.02) were increased in positive Ole e 2 patients compared with control subjects. DR2(15) phenotypic frequency was significantly increased (OR 5.6, Pc = 0.02) in positive Ole e 10 patients compared with control subjects. CONCLUSIONS: Our data suggest an association of Ole e 2 and Ole e 10 with bronchial asthma. Also, we found a genetic control of Ole e 2 and Ole e 10 IgE-specific responses that could be relevant to clinical disease in olive pollen allergy.

Olive allergen-specific IgE responses in patients with Olea europaea pollinosis.

BACKGROUND: Olive tree (Olea europaea) pollen is an important cause of pollinosis in the countries of the Mediterranean area. OBJECTIVE: This work aimed to study the IgE-binding frequency of Ole e 1, Ole e 2, Ole e 3, Ole e 6 and Ole e 7 from O. europaea pollen in a large population of olive pollen-allergic patients. METHODS: We studied: 119 consecutive patients with seasonal rhinitis and/or asthma and a positive skin prick test to O. europaea pollen extract; 10 atopic patients without history of pollinosis and a negative skin prick test to O. europaea; and 10 healthy controls. Allergens were purified from O. europaea pollen extract by reverse phase HPLC and characterized by N-terminal amino acid sequencing, MALDI analysis, and specific IgE immunodetection. Skin prick tests and ELISA titration against above mentioned purified olive pollen allergens were performed in all pollinic patients and controls. RESULTS: One-hundred and seven (90.7%) patients had a positive skin response to Ole e 1; 88 (74.6%) reacted to Ole e 2; 57 (47.9%) reacted to both Ole e 6 and Ole e 7; and 43 (37.8%) reacted to Ole e 3. The allergenic activity determined by ELISA to Ole e 1 was found in 84%; to Ole e 2 in 61.3%; to Ole e 3 in 31.9%; to Ole e 6 in 39.4%; and to Ole e 7 in 41.2% of patients. All patients had positive skin responses to at least one of the allergens tested, However, a combination of Ole e 1 and Ole e 2 together with a minor allergen Ole e 6 or Ole e 7, disclosed the same diagnostic value that was obtained with the use of crude olive pollen extract. The nonatopic and atopic control subjects did not react to any purified allergens on the skin prick test. CONCLUSIONS: These results indicate that Ole e 1 and Ole e 2 are major allergens in patients with O. europaea pollinosis in our population. A combination of a few olive pollen allergens can substitute the crude extract for in vivo as well as in vitro diagnostic purposes.

Immunological activity of recombinant Ole e 1 in patients with Olea europaea pollinosis.

BACKGROUND: Recombinant allergens have potential advantages over conventional allergenic extracts. However, these recombinant allergens should be evaluated for their antigenic activity and compared with their natural counterparts before being used for clinical purposes. METHODS: We studied 33 patients with seasonal rhinitis and/or bronchial asthma and a positive skin prick test to Olea europaea pollen extract, 10 atopic patients with no history of pollinosis and a negative skin prick test to O. europaea extract and 10 healthy controls. Skin prick tests and determination by ELISA of specific IgE to natural Ole e 1 (nOle e 1) and recombinant Ole e 1 (rOle e 1) expressed in Pichia pastoris were performed in all patients and controls. Inhibition assays were performed between nOle e 1 and rOle e 1 by ELISA. RESULTS: All patients with O. europaea pollinosis had positive skin test responses to both commercial O. europaea extract and nOle e 1 allergen, and all reacted to rOle e 1 on the skin prick test. The nonatopic and atopic control subjects with negative olive pollen skin test results did not react to rOle e 1 on the skin prick test, even at the highest concentrations, confirming the specificity of this test. We found a weak correlation between the wheal surface area produced by the prick test with nOle e 1 and the wheal surface area produced by rOle e 1 at 10 microgram/ml (r = 0.42, p < 0.05). Comparison of specific IgE against both nOle e 1 and rOle e 1 in the patients did not reveal any significant difference. There was a strong correlation between the amount of specific IgE against nOle e 1 and rOle e 1 (r = 0.99, p < 0.01). The two proteins displayed the same extent of binding inhibition to IgE antibodies in ELISA inhibition experiments. CONCLUSIONS: These results confirm the immunological activity of rOle e 1 expressed in P. pastoris and indicate that Ole e 1 is one of the major allergens in O. europaea pollinosis as evaluated by skin prick test and serological methods. The correlation between rOle e 1 and nOle e 1 in skin test results and serologic data indicates the potential of recombinant allergens for clinical applications and diagnosis of O. europaea pollen allergy.

High levels of Olea europaea pollen and relation with clinical findings.

BACKGROUND: Olea europaea pollen is an important cause of seasonal allergic rhinitis and bronchial asthma in southern Spain. For patients allergic to grass pol- len the critical concentration of airborn pollen is 50 grains/m3, but in the case of Olea pollinosis no data is available. METHODS: Fifty-six seasonal allergic rhinitis patients (29 in 1994 and 27 in 1995) were included in this study, all of whom lived in Jaen. Daily symptom card were filled in and pollen counts during May and June were performed in both years. A linear regression model was used for analysis of the airborne pollen concentration and the symptom score. RESULTS: Significant correlations among daily counts of Olea pollen and rhinitis symptoms were obtained. Most of our monosensitized patients needed a high Olea pollen concentration in the atmosphere (around 400 grains/m3) to suffer at least from mild allergic rhinitis symptoms. CONCLUSION: Local conditions with a wide area dedicated to olive tree cultivars result in a high concentration of this pollen in the atmosphere. Monosensitized Olea patients in our area seem to need exceptionally high levels to suffer from allergic symptoms.

Allergy to natural honeys and camomile tea.

Precipitation of food allergy reactions is well known in some patients with pollinosis when they consume natural food, such as honey or camomile tea. We present 9 patients with hay fever, with or without asthma, who experienced systemic allergic reactions after ingestion of natural honeys from two local areas (Andujar and Granada) and/or camomile tea. Pollen analysis showed a high level in sunflower pollen (23.6% of pollen grains) in the honey from Andujar but not in that from Granada. The diagnosis of food and respiratory allergy was based on history, skin prick tests and specific IgE activity against pollen from Compositae. Conjunctival challenge with camomile extract also gave positive results. The above allergological tests and the inhibition studies carried out, suggest that pollen of Compositae may be responsible for allergic reactions to certain natural foods and that the reactions are mediated by an IgE-related mechanism.

Regulation of the level of yeasts citrate synthase by oxygen availability.

The activity of yeasts citrate synthase in cells grown under different hypoxic conditions has been investigated. A linear relationship between the citrate synthase activity and the respiratory capacity of the cells has been found. When Saccharomyces cerevisiae was grown on fermentable substrates the activity decreased as the concentration of sugars in the medium increased. The enzyme of the yeast Rhodoturula showed a high activity in spite of the existence of high sugar concentration in the culture medium. Neither feed-back repression by glutamate nor feed-forward induction by ammonia has been found in bakers' yeast. The results suggest that the regulation of the enzyme by oxygen availability takes place by the ""de novo'' synthesis of the enzyme.