PubMed Health⌕ Search

Biomedical subjects

J Collette

Publications and source records attributed to J Collette.

18 recordsLinked to original sources
PubMed1992

Insulin-like growth factor II in two human colon-carcinoma cell lines: gene structure and expression, and protein secretion.

Abnormal expression and structural modification of the IGF-II gene in correlation with high IGF-II production have recently been described in human colorectal tumors in comparison with normal adjacent tissues. Here, we have studied IGF-II in 2 human colon-carcinoma cell lines, HT29 and COLO 320DM. RFLP analyses revealed no apparent alteration at the IGF-II locus in these 2 cell lines. HT29 cells weakly expressed IGF-II mRNA in comparison with the high over-expression previously observed in some colorectal tumors, and only the 4.8-kb mRNA species was present. In addition, the serum-free medium conditioned by HT29 cells contained high IGF-II levels (approx. 900 ng/10(8) cells), as measured in a specific IGF-II radioimmunoassay (RIA). After chromatography on Bio-Gel P-60, we observed that 64% of the total IGF-II secreted by HT29 cells were present as a high-molecular-weight form of about 17 kDa. In contrast, no detectable expression of the IGF-II gene was observed in COLO 320DM cells, and low IGF-II levels were secreted by these cells in the serum-free medium, with only 9% total IGF-II represented by the large species.

Carcinoma↗
PubMed1991

Tumor IGF-II content in a patient with a colon adenocarcinoma correlates with abnormal expression of the gene.

We have recently reported abnormal insulin-like growth factor-II (IGF-II) mRNA levels in a number of human colorectal adenocarcinomas. Using an IGF-II radioimmunoassay, we have now detected high levels of both 10-kDa and 7.5-kDa IGF-II species (2,370 ng/g) in a right colon tumor showing a 800-fold IGF-II gene over-expression in comparison to the normal adjacent tissue. The higher-molecular-mass form represents 74% of the total immunoreactive IGF-II detected in the tumor. This form appears to be less reactive in the radioreceptor assay than in the radioimmunoassay. The insulin-like growth factor-I (IGF-I) concentration in the tumor is low. The patient's pre-operative serum IGF-II level is not increased and the proportion of the 10-kDa species is normal. In addition, the IGF-II/IGF-I ratio is 3 in the serum and 308 in the tumor. Our results show that the very high IGF-II level produced by the tumor does not influence the seric concentration of the growth factor.

Adenocarcinoma↗
PubMed1991

Stimulatory effect of oestradiol-17 beta and tamoxifen on gross cystic disease fluid protein 15,000 production and mRNA levels in T47D human breast cancer cells.

Oestradiol-17 beta and tamoxifen regulate the synthesis of a gross cystic disease fluid protein (GCDFP-15) in T47D human breast cancer cells. Dose-response curves of GCDFP-15 mRNA contents and GCDFP-15 levels in culture media and cells versus hormone or antihormone concentration have been established. Production of GCDFP-15 was increased by oestradiol-17 beta, tamoxifen and 4-OH tamoxifen. The effect of tamoxifen and 4-OH tamoxifen was greater than the effect of oestradiol-17 beta. Moreover, oestradiol-17 beta and 4-OH tamoxifen acted synergystically in enhancing GCDFP-15 release. The strong oestrogenic effect of the antioestrogen tamoxifen in regulating GCDFP-15 may reflect an unusual interaction between the tamoxifen-oestrogen receptor complex and the DNA oestrogen-responsive elements. As oestrogen control of GCDFP-15 depends also on the cell line studied, investigation of GCDFP-15 could extend our knowledge of the possible mechanism of action of oestrogens or antioestrogens.

Base Sequence↗
PubMed1991

Effects of a hydrosoluble bacterial extract from Escherichia coli (OM-89) on cytokine production by peripheral blood mononuclear cells from healthy subjects and patients with rheumatoid arthritis.

OM-89 is a bacterial extract from escherichia coli, proposed as an immunomodulating drug for the treatment of rheumatoid arthritis (RA). Since immunological mechanisms may play a role in its action, the immunological effects of OM-89 were evaluated in vitro on peripheral blood mononuclear cells (PBMC) derived from healthy subjects and RA patients. Results indicated that in the absence of OM-89, production of the monokines interleukin-1 beta (IL-1 beta) and tumor necrosis factor-alpha (TNF-alpha) is increased, while that of the lymphokines interleukin-2 (IL-2) and interferon-gamma (IFN-gamma is decreased by phytohemagglutinin (PHA)-stimulated PBMC from RA patients as compared with PBMC from healthy subjects. In the presence of PHA, OM-89 enhanced the production of IL-1 beta, TNF-alpha, IL-2, and IFN-gamma. IL-1 beta and IL-2 curves obtained using increasing amounts of OM-89 did not differ depending on the source of PBMC. By contrast, in the presence of increasing amounts of OM-89, TNF-alpha secretion significantly higher and IFN-gamma secretion significantly lower with PBMC from RA patients compared to PBMC from healthy subjects. These data indicate that OM-89 acts on monocytes and T cells directly and/or indirectly and suggest a possible clinical activity by OM-89 in RA relative to its immunological properties.

Adjuvants, Immunologic↗
PubMed1990

Placental alkaline phosphatase in developing normal and abnormal gonads and in germ-cell tumours.

The evolution of the gonads during intra-uterine development has been followed by immunohistochemical demonstration of placental-like alkaline phosphatase (PLAP) at the germ-cell level. PLAP immunopositivity was restricted to the limited period when germ cells were not surrounded by granulosa or Sertoli cells. Abnormal fetuses or neonates presenting with chromosomal anomalies frequently had disorganized gonads where germ cells retained their membrane PLAP immunopositivity. This abnormal immunopositivity is similar to that expressed by abnormal germ cells in testicular in situ carcinoma, in gonadoblastoma (case of 45,XO/46,XY mosaic) and in seminoma. The pattern of positivity for other germ-cell tumours was highly variable. We suggest that in abnormal gonads, dysgenetic or neoplastic, an early embryonic property is retained by abnormal germ cells. Its importance in the process of neoplastic induction remains to be defined.

Adolescent↗
PubMed1990

Dual photon absorptiometry of lumbar spine in west European (Belgian) postmenopausal females: normal range and fracture threshold.

Bone mineral content (BMC) and bone mineral density (BMD) of lumbar spine have been measured in 695 healthy postmenopausal and 64 type I osteoporotic Belgian, Caucasian females. Bone loss is strongly correlated to time elapse from menopause (Tm) with a maximum rate of bone loss during the first five years of menopause. BMC (gHA) = 461 + 0.662 ln Tm -0.481 (ln Tm)2 and BMD (gHA/cm2) = 0.91 + 0.00711 ln Tm - 0.00846 (ln Tm)2 (in both cases p less than 0.001 and Tm expressed in months of menopause). After 20 years of menopause, 50 to 60% of normal women have vertebral BMC and BMD values below the 90th percentile of women with vertebral fractures and, thus, might be considered to have asymptomatic osteoporosis. We conclude that prevention of postmenopausal osteoporosis should be initiated as soon as possible after the onset of menopause and that bone density screening should be extended in elderly in order to detect and allow treatment of asymptomatic "densitometric" osteoporosis.

Absorptiometry, Photon↗
PubMed1990

Radioimmunoassay for human type II collagen.

Human articular cartilage type II collagen (h coll.II) was purified and used to develop a radioimmunoassay. The sequential saturation procedure allowed a sensitivity of 3 ng/tube. The intra and between assay coefficients of variation were less than 10 and 20% respectively in the linear part of the curve. The assay was highly specific for native human articular type II collagen. There was no cross-reactivity with other constituents of cartilage: human proteoglycans, fibronectin, laminin and hyaluronic acid did not interfere with the assay. No cross-reactivity existed with bovine collagen types I, III, IV. However, native collagens from human placenta (I, III, IV, V, VI), rat and calf skin type I collagens and bovine type II collagen produced a weak cross-reaction only at high doses. Concerning the latter, inhibition curves were not parallel. Parallelism of inhibition curves were observed for dilution of type II collagen, produced by human chondrocytes in three-dimensional culture. All of these characteristics indicate that radioimmunoassy of type II collagen is a very sensitive and specific method available for the study and quantification of type II collagen in in vitro experimental conditions.

Cartilage, Articular↗
PubMed1977

[Fibroblastic constrictive endocarditis. Apropos of a form localized in the left ventricle].

The authors report a case of a localised form of this strange disorder which was confined to the left ventricle, and in which the diagnosis was tentative for a long time. In this case it was possible to carry out a removal of the fibrous plaque after opening the apex of the left ventricle, the mitral valve being preserved, as described by Dubost; the functional and haemodynamic results of this procedure were very satisfactory.

Angiocardiography↗
PubMed1976

Simultaneous assays of cancer-associated antigens in various neoplastic disorders.

Five tumor markers were measured simultaneously in serum by radioimmunoassay: carcinoembryonic antigen (CEA), alpha-fetoprotein (AFP), human chorionic gonadotrophin (HGC), the beta subunit of HCG, and Kappa casein. In a population of 935 normal subjects these antigens were undetectable or found within precise limits. In patients with tumors of various origins the rate of pathologically elevated levels was 72% at the beginning of the clinical course (194 cases). This high rate was primarily due to the simultaneous measurement of CEA, betaHCG, HCG, and casein. AFP was of little importance. The simultaneous measurement of these tumor markers may be one biochemical element of diagnosis of carcinoma, although this criterion is neither absolute nor specific, as 14.7% of patients with non-neoplastic disorders (234 cases) were positive for one antigen. In the presence of metastases (112 cases) the rate of pathologic levels of at least one antigen was increased: 86% due to CEA and casein assay at the same time as their absolute levels were increased. Surgical removal reduces the rate of positivity of these antigens to 37%. As was shown in patients with breast cancer, the rate was 10% when the tumor had been removed at Stage N- and 54% when it was removed at Stage N+. Thus, the persistence of pathologic levels could be correlated with the capacity for recurrence or metastases. Finally chemotherapy, radiotherapy, or both, do not decrease the rate of positivity of the tumor markers.

Adult↗
PubMedDate not supplied

Prevention of postmenopausal bone loss by tiludronate.

76 healthy women, who had been menopausal for less than 96 months and who had never received any form of treatment to prevent bone loss, were entered into a randomised double-blind study. For the first 6 months, half the patients received tiludronate 100 mg daily, while the others received placebo. During the second 6 months, all patients received placebo. Bone mineral density of the lumbar spine decreased significantly by 2.1% (SE 0.8%) in the placebo group and did not significantly change in the tiludronate group (+1.33 [0.8]%). The difference in response between the groups was significant, as were the differences between values for corrected urinary hydroxyproline and calcium. Treatment with tiludronate was not followed by increased secretion of parathyroid hormone. A 6 month course of oral tiludronate may counteract postmenopausal bone loss for at least a year by decreasing bone resorption.

Absorptiometry, Photon↗
PubMedDate not supplied

Cancer-associated alteration of circadian rhythms in carcinoembryonic antigen (CEA) and alpha-fetoprotein (AFP) in humans.

A circadian rhythm of serum concentrations of two tumor markers (CEA and AFP) was demonstrated in individuals not suffering from cancer. These rhythms exhibited a diurnal peak with a nocturnal dip. They disappeared in cancer groups. However, in some cancer subjects, a circadian activity was still detectable, but with quite different characteristics (time of peak, amplitude) of rhythms when compared to controls. The importance of such findings is discussed with regard to the circadian kinetics of cancer cells, to time scheduled cancer treatments and to the detection of cancer.

Carcinoembryonic Antigen↗