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Biomedical subjects

R Moncayo

Publications and source records attributed to R Moncayo.

At least 55 records · Page 3Linked to original sources
PubMed1990

Evidence for the presence of human chorionic gonadotropin (hCG) and free beta-subunit of hCG in the human pituitary.

Previous studies have indicated that the pituitary gland may produce free alpha-subunit and small quantities of hCG in addition to other glycoprotein hormones. Since synthesis of holo-hCG requires the presence of both subunits, we have investigated the occurrence in human pituitary of free beta-subunit of hCG, in addition to intact holo-hCG. We processed a pituitary extract by fractionated ammonium sulfate precipitation followed by sequential chromatography on Sephadex G-100 and Ultrogel AcA 44. The fractions obtained were assessed for their reactivities with a panel of polyclonal and monoclonal antibodies specific for holo-hCG, beta-subunit of hCG, alpha-subunit, or hCG/LH. In addition to the expected LH and alpha-subunit, we detected materials which eluted from the column in positions very similar to those of cochromatographed 125I-hCG tracer and hCG-beta (NIH CR123-beta), and which showed immunoreactivity in specific immunoradiometric assays for holo-hCG and hCG-beta, respectively. Holo-hCG and hCG-beta material derived from the urine of a postmenopausal woman showed behaviors on the column similar to the pituitary forms. Both the pituitary holo-hCG- and free hCG-beta-subunit activity could be enriched (approximately 500 times) by affinity chromatography on an hCG antibody-coupled Sepharose column. When subjected to isoelectric focusing in granulated gel holo-hCG and hCG-beta-subunit of pituitary origin were focused in the pI-range of pregnancy hCG and pregnancy hCG-beta-subunit, respectively. Like pregnancy hCG, most (75%) of the pituitary hCG was bound to a column of Con A-Sepharose; however, the Con A-nonbinding hCG fraction (approximately 25%) was much higher than that found in pregnancy hCG. On the basis of immunoreactivities, the content of holo-hCG in our pituitary extract was estimated to be 60 micrograms/g, and that of free beta-subunit 45 micrograms/g; for comparison, LH was approximately 20 mg/g, and free alpha-subunit 1.6 mg/g. In addition, we could demonstrate the presence of both holo-hCG- and free hCG-beta-subunit-like immunoreactivity in NaCl-extracts from single pituitaries of two postmenopausal women. In these studies a second hCG-beta-immunoreactive material eluting far behind the hCG-beta-position was found. Chromatography of purified LH-beta-subunit, which crossreacts 1.56% in the hCG-beta IRMA, yielded an elution pattern clearly distinguishable from that of the hCG-beta-immunoreactive substances.(ABSTRACT TRUNCATED AT 400 WORDS)

Aged↗
PubMed1989

Organ-specific antibodies against ovary in patients with systemic lupus erythematosus.

We studied whether patients with systemic lupus erythematosus can have organ-specific antibodies directed against ovaries. With a recently developed enzyme-linked immunosorbent assay system that uses both a soluble and an extractable corpus luteum antigen fraction, we detected both IgG and IgM antibodies in the sera of patients with systemic lupus erythematosus (16 of 19, 84%). The highest levels of IgG antibodies were seen when the extractable organ fraction (ST80) was used as the antigen.

Antibodies↗
PubMed1989

Eye muscle antibodies in endocrine exophthalmos. Clinical and serological observations.

Serum samples were obtained from 65 patients with endocrine exophthalmos class I-V. In 33/65 patients who were treated either with prednisone or with ciclosporin, blood was sampled before, during and after therapy. Antibodies against eye muscle were determined during the course of immunosuppressive therapy in order to have an objective parameter of the therapeutic effect. To ascertain the specificity of the reaction both eye and abdominal muscles were used as antigens in an ELISA system. Both IgG and IgM antibodies were detected. In 45/65 patients (71%) eye muscle antibodies were positive before starting therapy. Antibodies were mostly detected in patients with active disease. Patients with exophthalmos of recent onset always had IgM antibodies whereas patients with chronic exophthalmos were mostly IgG positive. Patients with relapse showed mostly IgG but also IgG and IgM positivity in 2 cases. In 58% of cases only IgG antibodies were found whereas in 34% both IgG and IgM were detected and in 8% only IgM antibodies. There was no association between antibodies directed against eye muscle and thyroid microsomal and thyroglobulin antibodies or with the state of thyroid function. Furthermore there was no correlation between exophthalmos classes and eye muscle antibody binding activity. The antibody level declined during therapy with prednisone or with ciclosporin but rose again 8-12 weeks after stopping the drug in patients with progressive disease.

Adolescent↗
PubMed1989

Ovarian failure and autoimmunity. Detection of autoantibodies directed against both the unoccupied luteinizing hormone/human chorionic gonadotropin receptor and the hormone-receptor complex of bovine corpus luteum.

We developed an ELISA system for the detection of human anti-ovarian antibodies. Bovine corpora lutea were extracted in PBS (pH 7.2) and fractionated by ultracentrifugation. Both the soluble fraction obtained after 80,000 g (S80) and the Triton-extracted membrane fraction (ST288) were used as antigens. Additionally, the luteinizing hormone (LH)/human chorionic gonadotropin (hCG) receptor was isolated by affinity chromatography (wheat germ agglutinin and LH-Sepharose) and also used as an antigen. In 7 of 14 patients with primary sterility and endometriosis a positive reaction was observed. Similarly, 6 of 16 patients with secondary sterility and endometriosis were also positive. Patients being stimulated for in vitro fertilization and presenting either primary or secondary sterility were positive in 5 of 22 and 6 of 16 cases, respectively. In the S80 test 41 of 60 sera presented IgG2 antibodies, whereas in the ST288 test 38 of 60 belonged to the IgG1 subclass. Kappa and lambda chains were equally distributed. Some patients could recognize the unoccupied LH/hCG receptor as an antigen, while others recognized only the complex formed by the hormone plus the hormone receptor. The S80 and ST288 antigens were isolated by affinity chromatography. Gel permeation of the purified antigens revealed in each case the presence of an antigen complex. The apparent molecular weight was between 2,000 and 36,000 D. Cross-reactivity studies using affinity-purified antibodies demonstrated an antigenic relationship of the membrane, soluble, and extractable fractions. NAc-(beta-1----4)-D-glucosaminide and -D-galactopyranoside were the main terminal glycosides.

Addison Disease↗
PubMed1988

Similar effects of pulsatile and constant intravenous insulin delivery.

Effects of constant and pulsatile i.v. insulin delivery were examined in seven healthy subjects by means of euglycemic clamp technique. Each subject received constant insulin infusion (0.175 mU/kg.min) or insulin pulses at 12-min intervals (2.1 mU/kg) in randomized order for 8-h periods (08.00-16.00 h). Endogenous secretion of insulin was inhibited by concomitant administration of somatostatin (300 micrograms/h). Serum insulin concentrations during constant infusion (12 +/- 1 microU/ml) did not differ from basal values (11 +/- 1 microU/ml). Pulsatile insulin delivery resulted in oscillations of mean concentrations between values of about 10 and 20 microU/ml. Mean blood glucose concentrations during experiments were kept at 80 +/- 1 mg/dl, irrespective of the mode of insulin administration. Moreover, dextrose requirements for maintenance of these glucose concentrations did not differ over the hole periods of examination. We conclude that effects of constant and pulsatile delivery of basal amounts of insulin are not different. This at least applies to peripheral, short-term insulin administration in somatostatin-treated normal man, during an euglycemic clamp.

Adult↗
PubMed1988

Fat distribution, endocrine and metabolic profile in obese women with and without hirsutism.

The relationship between adipose tissue distribution, androgen levels, and metabolic complications of obesity was studied in 20 hirsute and 20 nonhirsute obese premenopausal women. The group of hirsute women showed preferentially an upper body type of obesity as assessed by the waist-to-hip ratio (0.902 + 0.017 v 0.778 +/- 0.015, P less than .01). They had higher serum concentrations of total testosterone (100.4 + 11.7 v 48.8 +/- 4.5 ng/dL, P less than .01) and lower levels of serum sex-hormone-binding globulin (28.1 +/- 3.6 v 44.0 + 4.2 nmol/L, P less than .05) exhibiting an increased androgenic activity as compared to the nonhirsute women. Serum glucose and insulin levels after an oral glucose load were significantly higher in the hirsute women. In addition, the group of hirsute females has significantly higher fasting concentrations of total cholesterol (5.82 +/- 0.28 v 4.75 +/- 0.14 mmol/L, P less than .05) and triglycerides (2.51 +/- 0.38 v 1.14 +/- 0.10 mmol/L, P less than .01). The hirsute group also showed higher systolic (166.7 +/- 5.1 v 142.1 +/- 4.5 mm Hg, P less than .01) and diastolic (100.9 +/- 3.6 v 85.2 +/- 2.5 mm Hg, P less than .01) blood pressure values than the nonhirsute women. Analysis of correlation revealed that an increasing waist-to-hip ratio was accompanied by increasing testosterone levels (r = .39, P less than .05) and by decreasing sex-hormone-binding globulin levels (r = .37, P less than .05).(ABSTRACT TRUNCATED AT 250 WORDS)

Adipose Tissue↗
PubMed1988

Islet cell antigens. Extraction studies and ELISA analysis.

Whole human and bovine pancreases were extracted in 20 mM Tris-HCl buffer without detergents and fractionated by high-speed centrifugation. The 80,000 x g supernatant was used to coat microtiter plates at a concentration of 5 micrograms protein/ml in phosphate-buffered saline. This solid-phase ELISA system was used for the detection of islet cell antigens defined by a series of monoclonal islet cell antibodies (HISL-1, -4, -5, -8, -14, and -19 and 4F2, 3G5, and A2B5). Both glycoprotein and glycolipid islet cell antigens in the total pancreatic extracts were detected by the monoclonal islet cell antibody in the ELISA system, indicating that epitope preservation had occurred during the extraction procedure. There was a good correlation between islet cell antigen quantitated by the ELISA system and the corresponding islet immunohistochemical reaction. Studies along these lines have the potential to facilitate the design of large-scale protocols for the purification of diabetes-related islet cell antigens to homogeneity.

Animals↗
PubMed1987

Growth hormone blocking antibodies in a patient with deletion of the GH-N gene.

We present another patient with the rare disorder of isolated GH deficiency (IGHD) type 1A. The diagnosis was confirmed by the clinical course, serology and genetic structure. Analysis of the post GH treatment serum of this patient with several thoroughly characterized monoclonal antibodies against GH established the presence of polyclonal, high titre and high avidity IgG-class antibodies against GH. These had the ability to neutralize GH as they could inhibit the binding of radiolabelled GH to GH-receptors on IM9 lymphoblastoid cells. DNA restriction mapping indicated a deletion of the GH-N gene and a family DNA pattern that was consistent with the proposed autosomal recessive aetiology of this disorder. These findings explain the inability of this patient to synthesize GH and his total immunological intolerance to GH replacement therapy.

Antibodies↗
PubMed1984

Hormonal dysregulations in severe burns.

Measurements of the concentrations of pituitary, thyroid and gonadal hormones have been made under both basal conditions and after adequate stimulation using a combined arginine TRH-LHRH stimulation test in 10 patients with deep burns covering between 30 and 70 per cent of the body surface during the first 20 days after injury. The most remarkable changes were found in the pituitary-gonadal system with testosterone concentrations significantly decreased at all times during the periods of study. Stimulation with LHRH resulted in a prompt response of FSH and LH during the first 10 days after burning whereas between 10 and 20 days after injury the basal concentrations for both hormones were significantly lower and showed a delayed response to stimulation. During the period of early fluid therapy large amounts of glucose without additional insulin were given, resulting in elevated blood glucose and high plasma insulin levels. It is concluded that normal pancreatic insulin production is sufficient to avoid excessive hyperglycaemia even during the period soon after burning. Compared with the findings in control patients the HGH levels in burned patients were not significantly different at any time during the periods of study.

Adolescent↗
PubMedDate not supplied

beta 1-Integrin expression in papillary thyroid carcinoma.

beta 1-integrins are widespread adhesion molecules which belong to a family of heterodimeric membrane glycoproteins and consist of two subunits, alpha and beta. Integrins seem to play an important role in the spreading and metastasis of malignant tumors. We investigated the expression and distribution of these adhesion molecules on papillary thyroid carcinomas by immunohistochemistry on formalin-fixed, paraffin embedded cancer tissues. We estimated the beta 1-integrin expression in cancerous areas in comparison to normal adjacent thyroid tissue. Our results revealed a highly significant difference in all investigated parameters between cancer and normal thyroid cells (p < 0.0001). Comparing our findings with the metastatic potential of the primary thyroid tumors, our results show that beta 1-integrin expression could be used as a prognostic parameter for papillary thyroid tumors.

Carcinoma, Papillary↗