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Biomedical subjects

H Pinto

Publications and source records attributed to H Pinto.

31 records · Page 2Linked to original sources
PubMed1979

Further evidence for the role of prolactin on human fetoplacental osmoregulation.

The addition of ovine prolactin (oPRL) to the fetal side of human term amnion in vitro is associated with a decrease in membrane permeability to tritiated water (THO). As the concentration of oPRL is increased from 2.5 to 20.0 micrograms per milliliter, permeability is progressively impaired. The addition of a specific prolactin receptor antibody completely abolished the effect of oPRL. Also, the addition of Ouabain abolished the effect of oPRL. When an osmolic gradient was created using Dextran-10 on the maternal side of the amnion, the bulk flow of water in control and 3PRL-treated membranes was not significantly different. These findings suggest that PRL acts predominantly on the diffusional flow rather than the bulk flow of water across amnion and that it is a transcellular transport. These studies also represent indirect evidence for the existence of prolactin receptor sites at the level of the amnion.

Amnion↗
PubMed1979

Evaluation of the gonadotrophic responsiveness of the pituitary to acute and prolonged administration of LH/FSH-releasing hormone (LH-RH) in normal females and males.

In normal females, the injection of 25 microgram of LH-RH (acute test) induced a greater LH and FSH release from the pituitary in the mid-luteal than in the mid-follicular phase of the menstrual cycle. In normal males, the responsiveness to 25 microgram LH-RH was greater than that in females at mid-follicular but not at the luteal stage. The pituitary response to the prolonged LH-RH infusion (0.21 microgram/min/8 h) was similar in both phases of the cycle of the females with a decline in serum gonadotrophins after the 4th hour and was paralleled by a significant increase of plasma oestradiol levels. In males the LH, but not the FSH secretion was lower as compared to female subjects, and gonadotrophin levels did not show a fall during the infusion. The acute injection of 25 microgram LH-RH at the end of a prolonged infusion induced the same response in the female subjects in both phases of the cycle. In males, the acute test following prolonged infusion produced a similar LH secretion, but a lower FSH response than in females. The comparison of the acute test alone and that preceded by a prolonged LH-RH infusion, demonstrated that, in females, the only significant differences consisted of a greater LH secretion in the former test in the mid-luteal phase. In males there was greater FSH secretion in the acute isolated test than when this test was given after the prolonged infusion.

Adult↗
PubMed1978

Preparation of iodine-125-labeled insulin for radioimmunoassay: comparison of lactoperoxidase and chloramine-T iodination.

The enzymatic radioiodination of porcine insulin by a system consisting of lactoperoxidase, hydrogen peroxide, and Na125I was compared with a modified chloramine-T technique. Satisfactory specific activity of the labeled hormone was obtained with the enzymatic iodination, with much greater immunoreactivity and stability than after chloramine-T, besides being quite suitable for the measurement of low plasma insulin levels. There was a positive and highly significant correlation between the insulin concentrations measured with the two tracers, with the regression line defined by the equation: y (chloramine-T) = 8.34 + 0.99 x (lactoperoxidase).

Animals↗
PubMed1977

Preparation of high-quality iodine-125-labelled pituitary human follicle-stimulating hormone (hFSH) for radioimmunoassay: comparison of enzymatic and chloramine-T iodination.

A method is described for the enzymatic radioiodination of human follicle-stimulating hormone (hFSH) by a system consisting of lactoperoxidase, hydrogen peroxide and Na125I. It was compared with the Chloramine-T modified technique. A satisfactory specific activity of the labelled hormone was obtained with the enzymatic iodination with much greater immunoreactivity was stability than after Chloramine-T.

Antibody Specificity↗
PubMed1977

Thermoluminescence in CaF2:Dy and CaF2:Mn induced by monoenergetic, parallel beam, 81-0 meV diffracted neutrons.

The thermal neutron thermoluminescent response of CaF2 : Dy (TLD-200, 0-35% wt Dy) and CaF2 : mn (TLD-400, 2% wt Mn) has been measured by exposure to a monoenergetic, parallel beam of 81-0 meV neutrons from a Kandi-II diffractometer. The TL dosemeters were rectangular and of 0-165 X 0-165 X 0-83 cm dimensions. The measured integral TLD-200 response for a neutron fluence of 10(10) n cm-2 was 0-21 +/- 0-013 R of 60Co which translates to 0-33 +/- 0-021 R 60Co for a Maxwellian neutron energy distribution at T = 293-6 K. The measured integral TLD-400 response for a neutron fluence of 10(10) n cm-2 was 0-09 +/- 0-006 R 60Co which similarly translates to 0-14 +/- 0-010 R 60Co for a Maxwellian neutron energy distribution at T = 293-6 K. The thermoluminescent response of both materials is both theoretically and experimentally shown to be composed of a thermal neutron induced prompt gamma component (approximately 20%) as well as the major component due to the thermal neutron induced beta decay of 165Dy and 56Mn. It is pointed out that the thermal neutron thermoluminescent response of both materials is size and geometry dependent.

Calcium↗
PubMed1975

Preparation of high-quality iodine-125-labelled pituitary luteinizing hormone for radioimmunoassay.

High quality pituitary luteinizing hormone labelled with 125-I was obtained after separating out the more heavily iodinated fractions, through starch gel electrophoresis, using the cathodal component (Fraction 1) which was further purified on Sephadex G-100, giving an almost pure 125-I-labelled luteinizing hormone preparation, presenting excellent immunoreactivity and low levels of damage on incubation in plasma. The quality control of the steps of the technique was done with plasma-coated talc (200 mg) which compared favorably, as far as being an indication of intact labelled luteinizing hormone, with the more time-consuming chromatoelectrophoresis.

Animals↗