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Biomedical subjects

B L Nguyen

Publications and source records attributed to B L Nguyen.

51 records · Page 3Linked to original sources
PubMed1978

Specific binding of estrogens in different fetal tissues of guinea pig during fetal development.

Cytosol and nuclear specific estradiol binding was evaluated in the fetal uterus, kidney, lung, and brain of guinea pig during fetal development and after birth. The quantity of specific binding sites increases during fetal development and decreases after birth, particularly that of the nuclei. An exception is the binding in the cytosol fraction of lung in which the number of available binding sites continues to increase in newborn animals. In the fetal uterus the amount of specific binding of estradiol and estrone is similar. The selective uptake of radioactivity and its localization by autoradiography in cell nuclei are in accordance with the high levels of estrogen receptors, particularly at the end of gestation.

Animals↗
PubMed1976

[Cytosolic and nuclear estradiol receptors in the fetal guinea pig uterus].

After administration in situ of 3H-estradiol (8 X 10(-10) moles) to Guinea Pig fetuses (48-58 days of gestation) the presence of specific estradiol receptors in the cytosol and in the nuclear extracts of the fetal uterus has been demonstrated. The presence of these estradiol receptors was confirmed after incubation of the same fetal tissues with 3H-estradiol (8 X 10(-8) M). Estradiol has a significant competitive effect on the 3H-estradiol-complex; estrone and estriol also have an effect but less intense. Testosterone, cortisol, aldosterone have no effect. By ultracentrifugation in sucrose density gradient of the cytosol fraction a component with a sedimentation coefficient of 8.5-9 S is observed. The dissociation constant of the 3H-estradiol receptor has a high affinity (KD = 4 X 10(-10) M).

Aldosterone↗
PubMedDate not supplied

Serum and intestinal diamine oxidase activity during intestinal adaptation.

Diamine oxidase (DAO) is a cytoplasmic enzyme found primarily in the villus epithelial cells of the small intestine. Serum DAO levels have been evaluated as a potential marker of intestinal disease in a variety of disorders, including gut atrophy, ischemia, and inflammation. In this study serum and tissue DAO levels were evaluated during intestinal adaptation. Twenty dogs were divided into 4 groups: sham laparotomy (n = 5), and 25% (n = 5), 50% (n = 5), and 75% (n = 5) distal enterectomy. Serum DAO activity (basal or postheparin) was measured prior to and 2 days, 4 weeks, 8 weeks, and 12 weeks after operation. Tissue DAO and changes in intestinal length, mucosal protein content, and villus height were measured at sacrifice 12 weeks later. Intestinal remnant length and protein content increased significantly with 50 and 75% resection. Tissue DAO activity was significantly decreased with any enterectomy. Serum postheparin DAO activity was significantly greater than basal at all time points but there was no significant change in either basal or postheparin DAO levels at any time following resection. It is concluded that serum DAO levels are not changed during the early adaptive period following intestinal resection and thus would not be useful as a marker of this process. Tissue DAO levels were diminished during adaptation, suggesting that tissue DAO activity is influenced not only by mucosal mass but by cellular metabolism and the proliferative status of the mucosa.

Adaptation, Physiological↗
PubMedDate not supplied

[Oestradiol receptors in foetal compartment (author's transl)].

Oestradiol concentration in the foetal plasma of guinea pig is 160-200 pg/ml (20-35 days of gestation), 200-300 pg/ml (35-45 days of gestation) and 170-450 pg/ml (45-60 days of gestation). After 3H-oestradiol administration to the foetus, this hormone circulates mainly as non-transformed 3H-oestradiol, 3H-oestrone and 3H-oestrone sulphate. 97-99% of the circulating oestradiol is found in unbound form. In vivo and in vitro studies in the foetus of guinea pig (40-55 days of gestation) show the presence of specific oestradiol receptors in the kidney, brain and Mullerian ducts of the foetus. The affinity constant in the cytosol of the brain is Kd=2 X 10(=9)M; in the cytosol kidney this value is Kd = 2.3 X 10(=10)M. A direct binding of 3H-oestradiol to the chromatin of the kidney was demonstrated with a Kd = 3.3 X 10(=10)M In the cytosol of Mullerian ducts the presence of a specific 3H-oestradiol macromolecule component with a sedimentation coefficient (in sucrose gradient) of 8-8.5S was detected. It is concluded that specific oestradiol receptors are present during foetal development in tissues such as kidney, brain and Mullerian ducts, but not in the liver.

Animals↗
PubMedDate not supplied

[Proceedings: Study of a new steroid: the 3beta,5alpha-tetrahydro-deoxycorticosterone (3alpha,5beta-tetrahydro-DOC). Its significance during pregnancy (author's transl)].

The physiological significance of a new steroid: the 3beta, 21-dihydroxy-5alpha-pregnan-20-one (3beta,5alpha-tetrahydro-DOC) was studied during human pregnancy. The urinary excretion values in the first and second trimester of pregnancy are 100-400 mug/24 h and in the third trimester the values increase to 240-1080 mug/24 h. This compound is not found in men nor in non-pregnant women but is found in the urine of newborns (2-12 DAYS): 25-80 mug/24 h. After perfusion of the fetus with H-deoxycorticosterone, 3H-3beta, 5alpha-tetrahydro-DOC was found in the fetal liver. These data suggest that this steroid could originate in the fetus: parallel studies of the urinary excretion of the other isomer : 3alpha821 dihydroxy-5beta-pregnan-20-one (3alpha,5beta-tetrahydro-DOC) shows that this compound increases at the end of pregnancy but its excretion rate is 2-3 times less than that of 3beta, 5alpha-tetrahydro-DOC.

Desoxycorticosterone↗
PubMedDate not supplied

Prominent crista terminalis mimicking a right atrial mixoma: cardiac magnetic resonance aspects.

A 68-year-old woman came to our observation with a clinical history of isolated systolic hypertension poorly controlled by the combination of ramipril 5 mg and hydrochlorothiazide 12.5 mg o.d. The ECG showed sinus rhythm with heart rate of 68 beats per minute and signs of left ventricular hypertrophy without strain. Further investigation included an echocardiogram that showed normal left and right cavities and normal cardiac valves. At the level of the posterior wall of the right atrial (RA) an apparent smooth, bean-like tumor, having a thin pedicle, was identified as a RA mixoma. Cardiac MRI was requested and showed in two sequential slices a muscular ridge, identified as a prominent crista terminalis. Some para-physiological structures sited in the RA may have the appearance of tumors, as crista terminalis, Eustachian valve extending into the RA chambers and Chiari network. The multiplain projections of MRI allow the cardiologist to identify the presence of intracardiac masses and to make a differential diagnosis between neoplasms and variant anatomic structures.

Aged↗
PubMedDate not supplied

Noninvasive assessment of coronary artery stenoses by multidetector-row spiral computed tomography: comparison with conventional angiography.

BACKGROUND: Coronary artery disease (CAD) is the most common cause of hospitalization and mortality in many industrialized countries. We analysed the diagnostic accuracy of multi-detector row spiral computed tomography (MDCT) in determining mid- to high-grade coronary artery stenoses (> 50%). METHODS: Sixty-nine patients with suspected CAD were referred to MDCT coronary angiography. Patients with a heart rate above 60 bpm received 20-40 mg propranol before the scan. The left main (LM), the left anterior descending artery (LAD), the first diagonal branch (D1), the right coronary artery (RCA) and the proximal tract of the circumflex artery (LCX) were independently evaluated by two blinded observers and screened for > 50% stenoses. The mean values of MDCT coronary narrowings assessed by two observers were compared to quantitative coronary angiography. RESULTS: MDCT correctly detected 95 of 123 coronary lesions (sensitivity 77.2%) and absence of stenoses was correctly identified in 388 of 426 segments (specificity 91%). The sensitivity for the LM, LAD, RCA and the proximal tract of LCX was 100%, 86.5%, 69.8% and 80% respectively. Classification of patients as having 1-vessel, 2-vessels, 3-vessels or left main disease was accurate in 75.4% (46/61) of patients. CONCLUSIONS: MDCT technology, combined with heart rate control, allows reliable noninvasive detection of hemodynamically significant CAD.

Coronary Angiography↗