Biomedical subjects

A Brena

Publications and source records attributed to A Brena.

4 recordsLinked to original sources

PubMed2006

The dynamics of estrogen receptor activity.

In the latest few years, the merging of imaging and animal engineering technologies has led to the generation of innovative tools that provide the opportunity to look into the dynamics of specific molecular events in living animals during their entire life under a completely renewed perspective. These tools will have a profound impact not only on basic research, but also on drug discovery and development allowing to depict the activity of any therapeutic agents in all their designed targets as well as in the organs where they may cause undesired effects. Along this research line, our laboratory has recently described the first animal model reporting the state of activity of estrogen receptors (ERs) in real time: the ERE-luc reporter mouse. The application of optical imaging to the ERE-luc has allowed an unprecedented in depth view of estrogen signaling in all of its target tissues. For example, the analysis of the state of activity of ERs in the physiological setting of the estrous cycle has provided compelling evidence that hormone-independent mechanisms are responsible for activating ERs in non-reproductive organs. This discovery may pave the way to a rational basis for the development of novel, more selective and effective treatments for menopause.

Animals↗

PubMed1997

Diagnosis of human immunodeficiency virus type 1 infection in infants by immune complex dissociation p24 assay.

Using immune complex dissociation (ICD), we retrospectively examined serum and plasma of 206 infants aged 0 to 4 months who were perinatally exposed to human immunodeficiency virus (HIV). All samples were analyzed in a blinded manner. Infection status was determined based on the results of HIV culture and Centers for Disease Control and Prevention classification. The overall diagnostic sensitivity of the assay was 59% (93 samples, 73 infants), and specificity was 100% (160 samples, 133 infants). When the samples were analyzed according to age, sensitivity was highest at age 1 to 2 months (17 of 21 infants, 81%). Sensitivities at other ages were 53% at < 1 month, 55% at 2 to 3 months, and 48% at 3 to 4 months (9 of 17, 11 of 20, and 12 of 25 cases, respectively). In 11 evaluable cases there was a possible correlation of p24 antigen quantitation (in picograms per milliliter) with disease progression. We conclude that, as determined in this study, the ICD p24 is a rapid diagnostic assay for HIV infection with a sensitivity of >80% at 1 to 2 months of age and 100% specificity, as evaluated, up to 4 months of age.

Antigen-Antibody Complex↗

PubMed1989

Endogenous digoxin-like immunoreactive factor and digitalis-like factor associated with the hypertension of patients receiving multiple alkylating agents as part of autologous bone marrow transplantation.

1. Hypertension is a complication of autologous bone marrow transplantation when therapy includes multiple alkylating agents. We have sought to identify the factors underlying this hypertension. We measured weight, serum creatinine, plasma renin activity, aldosterone and digoxin-like immunoreactive factor (DLIF), by digoxin radioimmunoassay, in 18 patients. Plasma catecholamines were also measured in five patients. 2. Of the 18 patients studied, 15 became hypertensive. The variable most consistently associated with these individuals' hypertension was DLIF activity which was increased in 14 of the 15 hypertensive patients (P = 0.055, Fisher exact test). Serum creatinine was increased at some point in seven of the 15 hypertensive patients, weight was increased in five and plasma renin activity and aldosterone were increased in one. Catecholamines were not increased in any of the five patients in which they were measured. 3. The association between changes in mean arterial pressure (MAP) and changes in DLIF for the group as a whole was assessed by analysing one data pair per patient, representing the maximal MAP. This correlation was significant (r = 0.75, P = 0.001). 4. Within individual patients, changes in MAP and changes in serum DLIF concentrations were significantly correlated (r greater than 0.50, P less than 0.05) in six of 15 hypertensive patients. 5. Digitalis-like factor (DLF) was measured by inhibition of (Na+,K+)-adenosine 5'-triphosphatase in five patients and DLF and DLIF were significantly correlated (r = 0.081, P = 0.0001). DLF and MAP were also significantly correlated (r = 0.59, P = 0.002). 6. This represents the first longitudinal study of the relationship between DLIF and blood pressure in hypertensive individuals, and the results suggest that DLIF may contribute to the increased blood pressure in some of these subjects.

Adult↗

PubMed1989

Increases in plasma digitalis-like factor activity during insulin-induced hypoglycemia.

Digitalis-like factor (DLF) appears to be widely distributed throughout the body, and has been specifically localized to the mammalian hypothalamus. In this study we monitored the DLF response to insulin-induced hypoglycemia in 11 normal males. Hypoglycemia was associated with a significant increase in serum DLF activity over basal values (40 +/- 5 pg digoxin Eq/ml, mean +/- SEM) at 60 min (83 +/- 8 pg digoxin Eq/ml) and 90 min (86 +/- 10 pg digoxin Eq/ml) following insulin administration (p less than 0.01). We measured the DLF response to insulin-induced hypoglycemia in other men after infusion of hypertonic saline (n = 8) or after oral water-loading (n = 8). Saline infusion (0.06 ml 5% saline/kg BW/min for 120 min prior to insulin infusion) or water loading (20 ml/kg BW over 60 min completed 30 min before insulin infusion) alone significantly increased serum DLF (saline: 21 +/- 5 to 60 +/- 18 pg digoxin Eq/ml, p less than 0.05; water: 18 +/- 11 to 49 +/- 15 digoxin Eq/ml, p less than 0.05). DLF activity was further significantly increased within each group 60 and 90 min after administration of insulin. In the group infused with hypertonic saline, insulin caused increases of serum DLF from 60 +/- 18 at time 0 to 170 +/- 17 pg digoxin Eq/ml at peak (p less than 0.01). Similarly, in the oral water-loaded group serum DLF increased from 49 +/- 15 at time 0 to 127 +/- 24 pg digoxin Eq/ml at peak (p less than 0.01) after they received insulin.2=

Adult↗