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Biomedical subjects

A Castro

Publications and source records attributed to A Castro.

At least 433 records · Page 24Linked to original sources
PubMed1987

Essential arterial hypertension: plasma and urinary aldosterone alterations.

We studied 52 patients with mild to severe essential arterial hypertension and ranging in age from 30 to 60 years (average, 44). Various biochemical and endocrinologic parameters were studied, with special emphasis on plasma aldosterone and urinary aldosterone. At the same time, a control group of 30 normal subjects (nonhypertensive) were studied under the same conditions. Both groups were carefully selected. Results indicated that the hypertensive group demonstrated a marked increase in plasma aldosterone levels (P less than .01) and an increase in the coefficient of plasma aldosterone/plasma renin activity (P less than .01). This indicates inadequate secretion of plasma aldosterone. There were no significant changes in the urinary aldosterone. Statistically significant changes were found in plasma renin activity (P less than .001) and plasma aldosterone (P less than .001) when the hypertensive patients were divided into two age groups, those under 45 and those over 45. These changes were not found in the normal subjects in the same age groups, indicating that age is an important influence on the renin-aldosterone system in hypertensive patients, and leads to variations in this hormonal axis similar to those observed in normal elderly subjects.

Adult↗
PubMed1986

Use effectiveness of a spermicidal suppository containing benzalkonium chloride.

A multicentric trial in 9 Spanish Clinics of Family Planning was conducted to evaluate the effectiveness of a vaginal contraceptive Ovule (suppository), containing 18.9 mg of benzalkonium chloride. Gynaecological and cytobacteriological examinations were made to evaluate any possible side-effect. Six-hundred-fifty-three women at risk of unwanted pregnancy accepted the method as the only contraception during 9,517 months. The results are expressed in life-tables (Tietze-Lewit). Net cumulative first segment rate at 12 months were: terminations 27.2; pregnancy 3.7; medical reason 2.3; planned pregnancy 2.8; other personal reasons 18.4. At 24 months the rates were: terminations 34.1; pregnancy 3.7; medical reason 2.6; planned pregnancy 6.5; personal reasons 21.3. Error or failure to use the spermicide resulted in 12 of 23 pregnancies (52%), while in another 4 pregnancies (17%) there were reasonable elements of doubt concerning its correct use. There were no gynaecological or cytological changes. We conclude that this product is a safe and very effective contraceptive if used according to the prescribed instructions and before any sexual encounter.

Adult↗
PubMed1986

Nicotine enzyme immunoassay.

In the present study of the use of racemic aminonicotine as a functionalized hapten, nicotine antibodies suitable for use in nicotine determinations have been produced from antigens in which both 'flexible' and 'semi-rigid' chains serve to couple racemic 6-aminonicotine to bovine serum albumin. Nicotine enzyme immunoassay has been developed for the first time using antibodies produced against 6-epsilon-aminocapramido -DL-nicotine and beta-galactosidase nicotine enzyme. The assay is a double antibody method which requires 60 and 15 min incubation respectively. The correlation of nicotine pooled plasma was found to be 0.994 with very good precision and accuracy. The sensitivity, defined as the concentration of nicotine measured at delta F/delta Fo = 90%, was found to be 10 micrograms/1. Samples of human smokers (N = 9) after 1 cigarette at 3 min were 50-100 micrograms/1, and at 15 min were 30-60 micrograms/1.

Animals↗
PubMed1985

Porphyria cutanea tarda and hepatocellular carcinoma. Frequency of occurrence and related factors.

In order to assess the incidence of hepatocellular carcinoma (HCC) in porphyria cutanea tarda (PCT), 83 patients (77 males, 6 females, mean age 57.4 years) were studied. Thirteen patients (15.7%) had HCC, all of whom were male and cirrhotics with a mean age of 58.5 years. HCC patients showed a statistically significant (P less than 0.0005) longer evolution time (23 years since onset of the cutaneous disease) than patients without HCC (9.4 years), while the age of onset was similar in both groups. Differences in alcohol intake and hepatitis B virus (HBV) markers were non-significant, although high prevalence (54%) of past HBV infection was found in both groups. In HCC development, attributable risks of 100% were found for cirrhosis (P less than 0.001), male sex (P = NS) and for age over 51 (P less than 0.025). Therefore, PCT harbours a high incidence of HCC; evolution time, cirrhosis and age over 51 appear to be the most important contributing factors.

Adult↗
PubMed1985

Radioimmunoassay of serum follicle-stimulating hormone and luteinizing hormone in the bottlenosed dolphin.

Commercially available radioimmunoassay (RIA) kits for human follicle-stimulating hormone (FSH) and luteinizing hormone (LH) were adapted for quantitation of these hormones in serum from bottlenosed dolphins (Tursiops truncatus). Serum samples from over 160 wild and 70 captive animals were assayed in order to determine basal concentrations of FSH and LH in these animals, as well as to detect possible differences between various groups. Mean FSH and LH levels for all animals were 0.22 +/- 0.08 and 0.37 +/- 0.18 ng/ml, respectively. Although wild animals had higher FSH and LH levels than captive ones, the differences were not statistically significant (P less than 0.07). However, both FSH and LH were significantly (P less than 0.01 and P less than 0.05, respectively) elevated in females when compared to males. Adults and peripubescent animals had significantly (P less than 0.01) higher LH levels than did juveniles. Among wild animals, serum concentrations of FSH and LH reflected seasonal differences. Samples obtained in early summer (Gulf of Mexico population) contained significantly (P less than 0.01) higher concentrations of FSH and LH than samples obtained in the fall (Indian River, Florida population). Both FSH and LH were significantly elevated in samples from confirmed pregnant animals as compared to the overall mean and to a sample from a confirmed nonpregnant female. Our observations indicate that these RIAs can reliably detect serum FSH and LH from bottlenosed dolphins and represent the first quantitation of these hormones in cetaceans.

Aging↗
PubMed1985

Urinary excretion of zinc in patients with essential arterial hypertension.

We report the finding of an increase in urinary zinc excretion in patients suffering from essential arterial hypertension; we find no clear explanation for this phenomenon. However, it merits a more thorough study, such as a comparison of zinc metabolism as altered by the hypertensive process. Also, urinary zinc excretion before and after (6 months) Captopril administration is reported.

Adult↗
PubMed1985

Estriol radioimmunoassay in plasma and urine.

A specific radioimmunoassay of estriol has been developed using an antiserum obtained by immunization of rabbits against 1,3,5 (10)-Estratrien -3, 16 alpha 17 beta-triol-6 one 6 carboximethyl oxime: BAS (Estriol 6-CMO-BSA). The tracer used was Estriol (2, 4, 6, 4, 3H (N)). This assay does not require prior hydrolysis, extraction or purification. Either plasma, serum or urine can be used. Urine only requires 100 microliter (1:5) dilution and 100 microliter in serum or plasma. An incubation time of 60 minutes is requires; a linear standard curve is obtained by logit-log extrapolation and a good correlation was obtained (r = 0.063) with estriol determination by comparison to a generally accepted colorimetric method. The detection range is from 100 pg to 50,000 pg in plasma or serum and urine. The specificity of the antibody was determined by studies of cross reactivity with other steroids. The sensitivity (100 pg) and accuracy were proven to be highly satisfactory. This method is simple, rapid and accurate.

Animals↗
PubMed1984

Insulin release pattern after blockade of catecholamine synthesis with alpha-methyl tyrosine in vivo.

Insulin release pattern in vivo was studied using 30 control rats and 30 rats treated with alpha-methyl tyrosine to block catecholamine synthesis in vivo four days before the time of investigation. The drug treated animals exhibited significantly higher fasting insulin levels, and also the first phase insulin release after the B cell was challenged with a glucose load was significantly higher in these animals than occurred in the controls. This observation implies that the B cell is modulated by the sympathetic nervous system in its function and the insulin release would vary according to the emotional state of the individual.

Animals↗