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Biomedical subjects

A Castro

Publications and source records attributed to A Castro.

At least 73 records · Page 4Linked to original sources
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↗
PubMed1979

Ectopic human chorionic gonadotropin in breast carcinoma.

Immunoreactive human chorionic gonadotropin (hCG) was found in 9 of 65 surgically removed malignant breast tumors. Concentrations ranged from 5 to greater than 500 mIU hCG/g tumor. hCG was measured by a beta-chain specific readiommunoassay. In further study of these specimens, an immunoperoxidase staining technique was used to stain for hCG in formalin-fixed sections. The hCG was shown to be localized within the cytoplasm and on the surface of the malignant cells.

Breast Neoplasms↗
PubMed1979

Automated radioimmunoassay of nicotine.

We have developed an automated nonequilibrium procedure for the radioimmunoassay of nicotine. The use of a unique iodinated nicotine derivative in this procedure gave a sensitivity of 10 micrograms/l for nicotine with a between-run precision of 7.4% and within-run precision of 6.0%. Nicotine levels of 60 to 67 micrograms/ml were found in subjects 15 min after smoking one standard cigarette. The technique herein reported is a very rapid, and sensitive radioimmunoassay for nicotine and facilitates the determination of nicotine in smoking subjects during the actual process of smoking.

Adult↗
PubMed1979

Immunoglobulin G- and M-specific enzyme-linked immunosorbent assay for detection of dengue antibodies.

An enzyme-linked immunosorbent assay for the detection of antibodies to dengue virus is described. This method correlates well with a hemagglutination inhibition technique. The enzyme-linked immunosorbent assay can also be specific for human immunoglobulin M antibodies when a mu-chain-specific antiglobulin-enzyme conjugate and fractionated serum are employed. By using this technique, dengue immunoglobulin M antibodies were demonstrated in an infant suspected of having a recent dengue infection.

Antibodies, Viral↗
PubMed1979

Enzyme-linked immunosorbent choriomammotropin assay.

We have devloped an enzyme-linked immunosorbent assay for determining choriomammotropin (human placental lactogen) in serum. Unlabeled hormone competes with choriomammotropin-beta-galactosidase conjugate for antibody bound to polystyrene tubes. The entire assay can be performed in 2.5 h with good precision. The coefficient of variation for one sample with a mean concentration of 5.6 mg/L, assayed 10 times on the same day, was 5.7%. The coefficient of variation for nine samples (3.5 to 9.0 mg/L) assayed on five different days was 7.9%. Forty-eight clinical samples were assayed (y) and compared with results obtained by radial immunodiffusion (x). The resulting regression equation was: y = 1.05x + 0.78; r = 0.91.

Enzyme-Linked Immunosorbent Assay↗
PubMed1979

Steric hindrance enzyme immunoassay (SHEIA); a novel method in enzyme immunoassay.

We have developed a new method for separation of antibody bound and unbound enzyme conjugates. The technique as applied to the assay of choriomammotropin involves the use of beta-D-galactosylamine bound to agarose to separate the unbound choriomammotropin-beta-galactosidase conjugates for antibody bound conjugates. When beta-galactosidase was conjugated with choriomammotropin using the N-hydroxy-succinamide ester of m-maleimidobenzoic acid the affinity of the enzyme conjugate to beta-D-galactosylamine attached to agarose diminished markedly following incubation with antibody. In a typical enzyme immunoassay of choriomammotropin, 5 microliter of swelled affinity gel per tube was required to precipitate unbound enzyme following one hour gentle shaking at room temperature. Choriomammotropin antibody was used at titer of 1:1,000. The standard curve for the assay was adjusted to cover a range of 0-10 mg/l with maximum sensitivity between 1-4 mg/l.

Animals↗