Prevalencia de Bartonella henselae en donantes de sangre y riesgo de transmisión sanguínea en Chile / Prevalence of Bartonella henselae in blood donors and risk of blood transmission in Chile

Resumen Introducción: Bartonella henselae es el agente causal de la enfermedad del arañazo del gato en personas inmunocompetentes y de la angiomatosis bacilar y peliosis hepatis en inmunocomprometidos. En Chile la prevalencia de anticuerpos contra B. henselae en niños y adolescentes sanos es de 13,3%, en personas con riesgo ocupacional 60,5% y en gatos 85,6%. No existen datos publicados respecto de la seroprevalencia en donantes de sangre en nuestro país, por lo que determinar si B. henselae se encuentra presente en la sangre de los donantes al momento de la donación es muy importante, ya que este microorganismo puede sobrevivir hasta 35 días en los eritrocitos almacenados en banco de sangre a 4 °C. Objetivo: Determinar la prevalencia de B. henselae en donantes de sangre. Metodología: Se analizaron 140 muestras de sangre de donantes, para detectar la presencia de B. henselae, utilizando la técnica de la reacción de polimerasa en cadena (RPC). Resultados: Se obtuvo 13,6% de los donantes de sangre con RPC positiva para la B. henselae. La secuencia de los fragmentos amplificados presentó una identidad por sobre 98% con respecto a secuencias de B. henselae de referencia. Conclusión: El riesgo de transmisión sanguínea debiera ser considerado en un país con alta seroprevalencia de infección por B. henselae.

Background: Bartonella henselae is the causal agent of cat scratch disease in immunocompetent persons and bacterial angiomatosis in immunocompromised patients. In Chile, the prevalence of antibodies against B. henselae in healthy children and adolescents is 13.3%, in persons with occupational risk 60.5%, and in cats 85.6%. There are no published data regarding the seroprevalence in blood donors in our country, so determining if B. henselae is present in the blood of donors at the time of donation is very important, since this microorganism can survive up to 35 days in the red blood cells stored in a blood bank at 4 °C. Objective: To determine the prevalence of B. henselae in blood donors. Methodology: 140 donor blood samples were analyzed to detect the presence of B. henselae, using the polymerase chain reaction technique. Results: 13.6% of the blood donors with positive polymerase chain reaction for B. henselae were obtained. The sequence of the amplified fragments showed an identity of over 98% with respect to B. henselae reference sequences. Conclusion: The risk of blood transmission is due to a country with high B. henselae infection.

[Prevalence of Bartonella henselae in blood donors and risk of blood transmission in Chile]. / Prevalencia de Bartonella henselae en donantes de sangre y riesgo de transmisión sanguínea en Chile.

BACKGROUND: Bartonella henselae is the causal agent of cat scratch disease in immunocompetent persons and bacterial angiomatosis in immunocompromised patients. In Chile, the prevalence of antibodies against B. henselae in healthy children and adolescents is 13.3%, in persons with occupational risk 60.5%, and in cats 85.6%. There are no published data regarding the seroprevalence in blood donors in our country, so determining if B. henselae is present in the blood of donors at the time of donation is very important, since this microorganism can survive up to 35 days in the red blood cells stored in a blood bank at 4 °C. OBJECTIVE: To determine the prevalence of B. henselae in blood donors. METHODOLOGY: 140 donor blood samples were analyzed to detect the presence of B. henselae, using the polymerase chain reaction technique. RESULTS: 13.6% of the blood donors with positive polymerase chain reaction for B. henselae were obtained. The sequence of the amplified fragments showed an identity of over 98% with respect to B. henselae reference sequences. CONCLUSION: The risk of blood transmission is due to a country with high B. henselae infection.

The compound 14-keto-stypodiol diacetate from the algae Stypopodium flabelliforme inhibits microtubules and cell proliferation in DU-145 human prostatic cells.

We investigated the effects of the drug 14-keto-stypodiol diacetate (SDA) extracted from the seaweed product Stypopodium flabelliforme, in inhibiting the cell growth and tumor invasive behavior of DU-145 human prostate cells. In addition, the molecular action of the drug on microtubule assembly was analyzed. The effects of this diterpenoid drug in cell proliferation of DU-145 tumor cells in culture revealed that SDA at concentrations of 5 microM decreased cell growth by 14%, while at 45 microM a 61% decrease was found, as compared with control cells incubated with the solvent but in the absence of the drug. To study their effects on the cell cycle, DU-145 cells were incubated with increasing concentrations of SDA and the distribution of cell-cycle stages was analyzed by flow cytometry. Interestingly, the data showed that 14-keto-stypodiol diacetate dramatically increased the proportion of cells in the G2/M phases, and decreased the number of cells at the S phase of mitosis, as compared with appropriate controls. Studies on their action on the in vitro assembly of microtubules using purified brain tubulin, showed that SDA delayed the lag period associated to nucleation events during assembly, and decreased significantly the extent of polymerization. The studies suggest that this novel derivative from a marine natural product induces mitotic arrest of tumor cells, an effect that could be associated to alterations in the normal microtubule assembly process. On the other hand, a salient feature of this compound is that it affected protease secretion and the in vitro invasive capacity, both properties of cells from metastases. The secretion of plasminogen activator (u-PA) and the capacity of DU-145 cells to migrate through a Matrigel-coated membrane were significantly inhibited in the presence of micromolar concentrations of SDA. These results provide new keys to analyze the functional relationships between protease secretion, invasive behavior of tumor cells and the microtubule network.

[Determination of 25-hydroxyvitamin D serum levels and its seasonal variations in healthy young people]. / Determinación de los niveles séricos de 25-hidroxivitamina D y sus variaciones estacionales en una población normal joven.

BACKGROUND: 25-hydroxyvitamin D has a longer half life and its serum levels have less daily variations than calcitriol. Thus, its measurement is a better indicator of vitamin D status. AIM: To measure 25-hydroxyvitamin D levels in normal subjects during summer and winter. PATIENTS AND METHODS: Vitamin D was measured using a competitive protein binding radioassay in 61 subjects (27 male) aged 21 to 57 years old, during July and August (winter) and February and March of the next year (summer). RESULTS: 25-hydroxyvitamin levels were 28.8 +/- 1.5 and 30.9 +/- 2.3 ng/ml during winter and summer respectively. No differences were found between men and women. Ninety five percent confidence levels were between 13 and 50 ng/ml. Levels in one patient with malabsorption were 9.3 ng/ml, in 2 patients with hypophosphatemic osteomalacia were 2.1 and 9.3 ng/ml, in 12 patients with alcoholic cirrhosis were 16.4 +/- 1.3 ng/ml, in 4 patients with primary osteoporosis were 23.3 +/- 0.7 and in three patients receiving vitamin D were 334 +/- 33.2 ng/ml. CONCLUSIONS: Normal levels of 25-hydroxyvitamin D range from 13 to 50 ng/ml in normal adults, there are no differences between men and women and seasonal variations are minimal.

[The effect of fluoxetine on insulin resistance in non diabetic obese patients]. / Efecto de fluoxetina sobre la insulino resistencia en pacientes obesos no diabéticos.

Fluoxetine, a serotonin re-uptake inhibitor with antidepressive and appetite reduction effects, could improve insulin sensitivity. The aim of this work was to assess this effect of fluoxetine in obese subjects. We studied 12 subjects with a body mass index over 30, with a normal oral glucose tolerance test and not subjected to dietary restrictions. Insulin sensitivity using Bergman's minimal model, sex hormone binding globulin (SHBG) and insulin like growth factor binding protein 1 (BP 1) were evaluated before and after three weeks of treatment with 60 mg OD of fluoxetine. During treatment, subjects lost a mean of 1.9 kg. When compared with basal values, insulin sensitivity index (S1) improved significantly at the end of treatment (1.71 +/- 0.44 and 2.72 +/- 0.63 respectively), SHBG increased (28.9 +/- 5.1 and 18.2 +/- 3.4 nM/ml respectively) and BP 1 did not change (2.8 +/- 0.9 and 1.5 +/- 0.3 ng/ml respectively). The changes in insulin sensitivity did not correlate with weight changes (r = 0.4 NS). Weight or insulin sensitivity changes did not correlate with initial degree of insulin resistance. We conclude that the improvement in insulin sensitivity elicited by Fluoxetine is not related to weight changes and may be useful in the treatment of insulin resistant obese subjects.

[The clinical estimate of adiposity is not a good predictor of insulin tissue sensitivity measured with a minimal model analysis]. / La estimación clínica de la adiposidad no es un buen predictor de la sensibilidad tisular a la insulina medida con un analisis de modelo mínimo.

Fifteen male volunteers, aged 30 to 40 years old, were classified according to body mass index (BMI) as lean (n = 5, BMI less than 20 kg/m2), normal (n = 5, BMI 20-25) or obese (n = 5, BMI over 30). Glucose intolerance was ruled out by a normal oral glucose tolerance test and insulin sensitivity (SI) and glucose effectiveness (SG) were estimated by a minimal model analysis of a frequently sampled intravenous glucose tolerance test modified by an intravenous insulin injection at minute 20. The MINMOD program was fed with 29 or 12 values (reduced sampling schedule). Despite a significant inverse correlation between BMI and SI (r = -0.533 p < 0.05), the latter parameter overlapped among groups and the correlation was lost when obese individuals were not considered. Waist/hip ratio correlated modestly with SI (r = -0.52 p < 0.05). SG did not correlate with BMI. Using the reduced sampling schedule. SI values had a correlation coefficient of 0.78 with those calculated using the usual sampling schedule, although they were 82% lower. We conclude that only a BMI of over 30 accurately predicts a low SI, and that waist/hip ratio does not have a better predictive power.

The role of thyroid hormones in the control of beta-adrenergic receptors in rat mammary gland.

We have studied the effect of hyperthyroidism and hypothyroidism on the lactating rat mammary gland number of beta-adrenergic receptors and basal intracellular cyclic AMP levels. We also describe the effects of isoproterenol, cholera toxin and forskolin challenge on these parameters. Using cyclic AMP levels as an indication of receptor functionality our results indicate that both thyroid states are accompanied by a decrease in the response to beta-adrenergic receptor stimulation.

Comparative subcellular distribution of apyrase from animal and plant sources. Characterization of microsomal apyrase.

1. Apyrase (ATP: diphosphohydrolase) has been found in the microsomal fraction of rat salivary gland, mammary gland and uterus. 2. This enzyme, already described in plant tissue, is mainly present as a soluble polypeptide in tubers of Solanum tuberosum. 3. A fraction of this enzyme is associated with the microsomal fraction with a higher specific activity than the soluble one, for either ATP or ADP as substrate. 4. Apyrase bound to microsomes from rat and potato tissues was characterized in its substrate specificity and effect of inhibitors. 5. The Km values for ATP and ADP, optimum pH and metal ion requirement were determined. 6. A characteristic common to the microsomal and soluble apyrases is the stimulatory effect of a potato activator protein of soluble plant apyrase. 7. The microsomal-bound apyrase from rat and potato tissues were solubilized and subjected to size-exclusion chromatography. 8. The mammary gland and salivary gland apyrases eluted as molecular aggregates, in contrast to the uterus and potato enzyme.

[Heterologous hormonal regulation in the mammary gland]. / Regulación hormonal heteróloga en glándula mamaria.

Mammary gland growth and differentiation are largely dependent on a complex and interrelated action of many different hormones which makes the mammary tissue a very suitable one for the study of heterologous hormonal regulation. This type of control is analyzed by two different approaches: 1. The participation of estradiol in prolactin action during lactation, and 2. The role of glucocorticoids and thyroid hormones in the control of functional activity of rat mammary gland beta-adrenergic receptors.