Evaluation of plasma nucleosome concentrations in dogs with a variety of common cancers and in healthy dogs.

BACKGROUND: Cell free DNA, in the form of nucleosomes, is released into circulation during apoptosis and necrosis in a variety of diseases. They are small fragments of chromosomes that are composed of DNA wrapped around a histone core made of four duplicate histone proteins forming an octamer. The nucleosome compartment is a relatively uninvestigated area of circulating tumor biomarkers in dogs. The objectives of this study were to quantify and better characterize nucleosome concentrations in 528 dogs with various common malignancies and compare them to 134 healthy dogs. RESULTS: The sensitivity of increased circulating nucleosome concentrations for the detection of cancer in all dogs was 49.8% with a specificity of 97% with an area under the curve of 68.74%. The top 4 malignancies detected by the test included lymphoma, hemangiosarcoma, histiocytic sarcoma and malignant melanoma. The malignancies least likely to be detected were soft tissue sarcomas, osteosarcoma and mast cell tumors. CONCLUSIONS: A variety of tumor types may cause increased nucleosome concentrations in dogs. Tumors of hematopoietic origin are most likely to cause elevations and local tumors such as soft tissue sarcomas are least likely to cause elevations in plasma nucleosome concentrations.

Placental growth hormone and IGF-I in a pregnant woman with Pit-1 deficiency.

The respective contributions of pituitary and placental GH to circulating IGF-I in pregnant women have not been well established. We measured the serum concentrations of placental growth hormone (PGH) and IGF-I in a woman with pit-1 deficiency before, during and after pregnancy, resulting in the birth of a healthy child (not pit-1 deficient). Both PGH and IGF-I concentrations were below the assay detection limit before and after pregnancy. During pregnancy, PGH and IGF-I levels increased steadily; the concentrations of PGH and IGF-I in late pregnancy were comparable with levels previously measured in normal pregnancies. PGH and IGF-I concentrations were strongly correlated throughout pregnancy (r = 0.90; P = 0.002). PGH was undetectable in cord serum, whilst the IGF-I concentration was within the normal range. The findings of this case study corroborate the notion that PGH is the prime regulator of maternal serum IGF-I during pregnancy.

Placental growth hormone (GH), GH-binding protein, and insulin-like growth factor axis in normal, growth-retarded, and diabetic pregnancies: correlations with fetal growth.

We previously described significant changes in GH-binding protein (GHBP) in pathological human pregnancy. There was a substantial elevation of GHBP in cases ofnoninsulin-dependent diabetes mellitus and a reduction in insulin-dependent diabetes mellitus. GHBP has the potential to modulate the proportion of free placental GH (PGH) and hence the impact on the maternal GH/insulin-like growth factor I (IGF-I) axis, fetal growth, and maternal glycemic status. The present study was undertaken to investigate the relationship among glycemia, GHBP, and PGH during pregnancy and to assess the impact of GHBP on the concentration of free PGH. We have extended the analysis of specimens to include measurements of GHBP, PGH, IGF-I, IGF-II, IGF-binding protein-1 (IGFBP-1), IGFBP-2, and IGFBP-3 and have related these to maternal characteristics, fetal growth, and glycemia. The simultaneous measurement of GHBP and PGH has for the first time allowed calculation of the free component of PGH and correlation of the free component to indexes of fetal growth and other endocrine markers. PGH, free PGH, IGF-I, and IGF-II were substantially decreased in IUGR at 28-30 weeks gestation (K28) and 36-38 weeks gestation (K36). The mean concentration (+/-SEM) of total PGH increased significantly from K28 to K36 (30.0 +/- 2.2 to 50.7 +/- 6.2 ng/mL; n = 40), as did the concentration of free PGH (23.4 +/- 2.3 to 43.7 +/- 6.0 ng/mL; n = 38). The mean percentage of free PGH was significantly less in IUGR than in normal subjects (67% vs. 79%; P < 0.01). Macrosomia was associated with an increase in these parameters that did not reach statistical significance. Multiple regression analysis revealed that PGH/IGF-I and IGFBP-3 account for 40% of the variance in birth weight. IGFBP-3 showed a significant correlation with IGF-I, IGF-II, and free and total PGH at K28 and K36. Noninsulin-dependent diabetes mellitus patients had a lower mean percentage of free PGH (65%; P < 0.01), and insulin-dependent diabetics had a higher mean percentage of free PGH (87%; P < 0.01) than normal subjects. Mean postprandial glucose at K28 correlated positively with PGH and free PGH (consistent with the hyperglycemic action of GH). GHBP correlated negatively with both postprandial and fasting glucose. Although GHBP correlated negatively with PGH (r = -0.52; P < .001), free PGH and total PGH correlated very closely (r = 0.98). The results are consistent with an inhibitory function for GHBP in vivo and support a critical role for placental GH and IGF-I in driving normal fetal growth.

Lymphoid cell apoptosis induced by trophoblastic cells: a model of active foeto-placental tolerance.

To test the hypothesis that CD95-L (Fas-L) present on trophoblastic cells plays a part in establishing foeto-placental tolerance by inducing apoptosis of immune defence cells, we cocultured trophoblasts with lymphoid cells and scored the frequency of cell death in these cultures. We prepared human trophoblastic cells from term placentas removed by C-section and placed them in culture for 48 h before introducing the lymphoid cells. We added Jurkat cells, a CD3 + lymphoid cell line, or purified T cells from human blood to the cultured trophoblasts and monitored apoptosis by electron microscopy and flow cytometry after TUNEL or annexin V labelling. The frequency of cell death in the CD3 + cell population was higher when the lymphoid cells were cocultured with trophoblastic cells than when they were cultured alone. This frequency increased with time but was reduced when anti-CD95-L antibodies were added to the culture medium. Cell death was less frequent in the lymphoid cell population when trophoblasts were replaced with human fibroblasts not expressing CD95-L.

Maternal serum placental growth hormone and insulinlike growth factor binding proteins 1 and 3 in pregnancies affected by fetal aneuploidy and other abnormalities: implications for prenatal diagnosis of trisomy 21.

In the present study, we determined circulating serum levels of human placental growth hormone (hPGH) and insulinlike growth factor binding proteins 1 and 3 (IGFBP-1 and IGFBP-3) using two-site radioimmunoassays during the gestational midtrimester of pregnancies affected by chromosomal disorders with the aim of identifying potential marker substances that might have a significant discriminative and predictive value for prenatal diagnosis of fetal chromosomal aberrations and of organ malformations such as neural-tube defect. Our results show that the maternal serum levels of hPGH were significantly elevated in pregnancies affected by chromosomal anomalies or organ malformations as compared with controls. The distribution of IGFBP-1 concentrations for all experimental groups except trisomy 21 were closely similar to the normal population. IGFBP-3 decreased slightly in pregnancies affected by Down syndrome. These findings suggest that hPGH may be useful as an additional marker in prenatal screening for Down syndrome.

Serum level of placental growth hormone is raised in pregnancy rhinitis.

OBJECTIVE: To describe any relationship between pregnancy rhinitis and weight gain or serum levels of estradiol, progesterone, placental growth hormone, or insulinlike growth factor I. PATIENTS: Twenty-seven nonsmoking healthy pregnant women aged 22 to 38 years (mean age, 28 years) who had no history of respiratory allergy or chronic nasal or sinus problems volunteered to enter the study. They had no nasal complaints at entry. METHODS: Nasal patency was registered daily from early pregnancy until 1 month after delivery. Nasal and oral peak expiratory flow rates were established, and the subjective blockage was scored from 0 to 4, with 0 indicating no blockage. Serum samples were collected and weight was measured on 4 occasions during pregnancy and again at the end of the study. Pregnancy rhinitis was diagnosed if the subjective nasal obstruction score was 1 or higher every morning for at least 6 weeks immediately preceding delivery, then returned to 0 within 2 weeks and remained at 0 until the end of the study. If on any day other signs of respiratory tract infection occurred, that day was excluded. RESULTS: Pregnancy rhinitis was diagnosed in 5 women. These 5 women showed significantly higher levels of placental growth hormone than the women without the diagnosis. No significant difference was found between the 2 groups regarding body weight or any of the other serum levels studied. CONCLUSIONS: Serum level of placental growth hormone is raised in pregnancy rhinitis and may be involved in its pathogeny. Pregnancy rhinitis does not significantly raise weight gain or serum levels of estradiol, progesterone, or insulinlike growth factor I.

Isolation and culture of somatotrophs from the pituitary of the rainbow trout: immunological and physiological characterization.

The aim of the present paper was to obtain somatotroph- and gonadotroph-enriched populations from collagenase dispersed pituitaries of male rainbow trout. Inasmuch as the percentage of immunoreactive gonadotrophs and somatotrophs present in pituitaries was higher at spermiation than at the beginning of spermatogenesis, we tried such a cell separation with fish at this stage of spermatogenesis. Cells were fractionated using their differences in buoyant density with centrifugation in Percoll solutions. The use of Percoll linear gradients (1.110 to 1.027 g/ml) showed that somatotroph cells have a density of between 1.102 and 1.064 g/ml whereas gonadotrophs are spread over the range of the gradient. It was thus possible, by using linear or discontinuous Percoll gradients, to obtain 95 to 67% (mean 80%) enriched somatotropic cell fractions while no enriched gonadotropic cell fractions were collected. The fractionated cells kept their ability to be cultured and to be responsive to specific secretagogues. Somatostatine induced a 80 to 85% decrease in growth hormone release per somatotroph in the initial cell suspension as well as in the different cell fractions. On the other hand, the basal growth hormone release per cell was lower in the fractions containing cells with a density lower than 1.062 g/ml. Inversely, the gonadotrophs have a basal release per cell independent of their density, and this is also available for their responsiveness to salmon gonadotropin-releasing hormone.

Gonadotropic hormone (GtH) receptors in the testis of the troutSalmo gairdneri: in vitro studies.

A particulate fraction obtained from trout testis at the time of spermiation shows saturable binding sites for(125)I-labeled salmon gonadotropin ((125)I-GtH). Non-gonadal tissues (liver, muscle and spleen) did not demonstrate specific(125)I-GtH binding. The tracer's specific activity was determined by the self-displacement method (18 to 30 µCi/µg). Maximal specific binding ability of(125)I-GtH varied from 20 to 30% of the labelled ligand added, depending on the hormone preparation. Specific binding of(125)I-GtH to 20 mg of the testis membrane varied from 40 to 85% of the total binding depending on the method of membrane prepratation, and was competitively inhibited by concentrations of unlabelled GtH ranging from ca 1 to 1000 ng/ml of incubate. Gonadotropin of mammalian origin, ovine TSH or salmon prolactin competed only weakly, or not at all, for testicular gonadotropin binding sites (relative potencies s-GtH>>FSH=hCG>s-PRL>bTSH). Scatchard analysis of equilibrium binding studies shows that saturable gonadotropin binding was due to a class of high affinity binding sites (sites I Ka≊3×10(10) M(-1)) and possibly to a second class of lower affinity binding sites (sites II Ka=5 to 14×10(8) M(-1)). The binding capacity of sites I, as measured in enriched membrane preparations, was 45±18 fmoles/g of testis during the period of spermiation. The concentration of GtH required to obtain half maximal displacement of(125)I-GtH in the binding studies was of the same order of magnitude as the apparent ED50 for GtH stimulation of 11-Cetotestosterone (11KT) secretion by trout testesin vitro. Mammalian LH and FSH were 100 to 1000 folds less potent than salmor GtH to increase 11 KT secretion.