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Biomedical subjects

L Lorenzo

Publications and source records attributed to L Lorenzo.

5 recordsLinked to original sources
PubMed1992

Monoclonal antibodies to beta subunit of choriogonadotropin: development and use in a sandwich ELISA pregnancy test.

Balb/c mice were immunized with beta subunit isolated and purified from crude human chorionic gonadotropin preparations. Spleen cells from the higher titered mouse were fused with Sp 2/0 myeloma cells. Four specific secreting hybridomas were obtained. Specificity, affinity, and suitability of secreted antibodies for use in enzyme immunoassays were studied. Ascites of the selected hybridoma was raised; the antibody was purified by protein A-affinity chromatography and coupled to horseradish peroxidase. This conjugate was employed in a simultaneous sandwich enzyme immunoassay on microtiter plates sensitized with goat polyclonal antibody to measure the hormone. The test has a sensitivity of 10 mlU/ml either on urine, serum, or plasma samples when read in a microplate reader. The results can also be evaluated by the naked eye, with a sensitivity of 20 mlU/ml. No cross reactivity was detected with other human gonadotropins.

Animals↗
PubMedDate not supplied

Ionized calcium: its significance and clinical usefulness.

Maintenance of normal blood levels of ionized calcium (Ca2+) plays an important role in the management of the critically ill patient. Therefore, Ca2+ should be collected properly and measured reliably. The sound analytical performance of today's Ca2+ analyzers using ion-selective electrode technology have made measurements accurate and precise. The introduction of this technology allows rapid and direct analysis in whole blood or serum, resulting in an enhanced reporting time. Since the amount of heparin in the syringe was shown to lower plasma ionized calcium concentration artifactually, samples for plasma Ca2+ determination should be anticoagulated with a measured quantity of heparin. Ancillary factors in Ca2+ determination include effects of changes in sample pH, and situations where abnormal concentrations of calcium ligands are present. Many clinical situations require Ca2+ rather than total calcium measurements. Liver transplantation, citrated blood transfusions, and neonatal hypocalcemia are examples of a few such circumstances where determination of Ca2+ may be more physiologically and clinically meaningful than total calcium.

Adult↗
PubMedDate not supplied

[Establishment of circadian rhythm of cortisol in newborn and older children (author's transl)].

In 30 children, 19 males and 11 females, aged 5 days to 36 months admitted for reasons other than neurological, endocrine, hepatic or renal diseases, the plasma cortisol levels at 9.00 and 20.00 hr. was studied to ascertain the time of appearance of a pattern of circadian rhythm comparable to adults. Children were arbitrarily divided into three groups according to their age: group I (n = 9) 5 days to 6 months; group II (n = 13) 7 to 17 months and group III (n = 8) 24 to 36 months old. The plasma corticol levels at 9.00 and 20.00 hr. were respectively for each group (X +/- SD): 12.7 +/- 8.0; 10.9 +/- 8.62; 17.7 +/- 6.65; 11.9 +/- 7.5 and 21.6 +/- 4.67; 9.7 +/- 3.8 microgram/100 ml. Evidence for circadian rhythm was statistically demonstrated only in group III and from these individual results the criteria to be satisfied as evidence of rhythm are: the cortisol value at 20.00 hr. must be less than or equal to 15.0 microgram/100 ml. with a decrease greater than or equal to 30% compared to basal (9.00 hr.) value. Only 7 out of 13 children in group II and 4 out of the 9 children in group I conform such criteria. These results show that the circadian rhythm of cortisol might be used as a valuable test to study adrenal function in children from the age of two.

Adrenal Glands↗