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 47,337 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

In the present study, we have examined the role of gonadotropins and prostaglandins in the preovulatory increase of ovarian collagenase activity in the rat. Whole ovaries of immature PMSG-primed rats (20 IU) were removed before and 8 h after the rats were treated with human (h) CG, Nembutal, and/or indomethacin. The ovaries were homogenized in a solution containing Triton X-100 (0.25%) and centrifuged. Collagenase was extracted by resuspending the pellets in buffer containing 100 mM CaCl2, heating to 60 C for 6 min, and centrifuging. The supernatants were treated with dithiothreitol (2 mM) and iodoacetamide (5 mM) to inactivate collagenase inhibitors. Collagenase activity was measured as the percent digestion of 3H-type I collagen/100 microliters aliquot of ovarian sample. At zero time (52 h after PMSG), ovarian collagenase activity was 4.2 +/- 1.2% digestion (mean +/- SEM, n = 3). In ovaries collected 8 h after the endogenous LH surge or 8 h after the administration of 10 IU hCG at time zero, collagenase activity rose to 19.6 +/- 2.1 (n = 6) and 22.5 +/- 1.7% digestion (n = 11), respectively. Indomethacin (1.5 mg/100 g BW) administered 30 min after hCG, produced no change in collagenase activity (24.8 +/- 2.5% digestion, n = 7) although the expected increase in ovarian prostaglandin E after hCG treatment was blocked. When the endogenous LH surge was blocked with Nembutal (3 mg/100 g BW), collagenase activity in 8-h ovaries was 6.8 +/- 1.1% digestion (n = 10). The Nembutal block of the preovulatory collagenase increase was overcome by administration of hCG (8-h ovarian enzyme activity = 22.7 +/- 3.2% digestion, n = 8). These observations demonstrate that hCG stimulates ovarian collagenase activity and that this stimulation is not dependent on prostaglandin synthesis.
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PMID:The preovulatory increase in ovarian collagenase activity in the rat is independent of prostaglandin production. 300 37

Culture supernatants from monolayer cultures of human chondrocytes were tested for the presence of collagen type I and type II during subpassaging using an inhibition Elisa. The sensitivity of the Elisa was 404 +/- 50 ng/ml (mean +/- SEM) for the determination of type I collagen and 112 +/- 16 ng/ml for type II collagen. Whereas using immunofluorescence techniques, type II collagen was observed in human chondrocytes cultured under monolayer conditions only up to the first subpassage (1), in culture supernatants from human chondrocytes type II collagen could be found up to the fourth subpassage. Type I collagen was detectable in supernatants from the beginning of primary cultures and was present up to the tenth subpassage in increasing concentrations. Variations in the amount of collagen present in the culture supernatants seemed in part to be due to different growth characteristics of the chondrocytes. Cell shape was not associated with the release of a particular collagen type. In summary, the collagen inhibition Elisa appears to be equivalent to biochemical methods with regard to sensitivity and specificity. Investigations on influencing the switch in collagen production in human chondrocytes may benefit from the use of both techniques described.
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PMID:Demonstration of collagen type conversion in culture supernatants from human chondrocytes by an inhibition ELISA. 322 25

Blood mononuclear cells from patients with rheumatoid arthritis produce the lymphokine, leukocyte inhibitory factor (LIF) in response to collagens in vitro, and blood monocytes release prostaglandins (PGE2) and a factor, mononuclear cell factor (MCF) which stimulates collagenase and PGE2 production by cultured synovial cells. We therefore examined the effect of collagens on the production of PGE2 and MCF. Blood mononuclear cells from 6 patients with rheumatoid arthritis and 6 normal subjects were cultured in native human types I, II, or III collagen-coated tubes, or with streptokinase-streptodornase (SK-SD), and the supernatant media derived from these cultures analyzed for the presence of MCF, PGE2, and LIF. Types II and III collagens, as well as SK-SD, markedly stimulated MCF production by the cells from all 12 subjects (MCF activity, expressed as a mean stimulation index (SI) +/- SEM, was 43 +/- 12 for type II, 33 +/- 7 for type III, and 37 +/- 23 for SK-SD). Type I collagen was less stimulatory (mean SI 10 +/- 7). Cells from the patients with rheumatoid arthritis, but not the normal subjects, produced LIF in response to types II or III collagens but not to type I collagen. PGE2 production by blood mononuclear cells paralleled that of MCF, although abrogation of PGE2 release with indomethacin did not reduce MCF production. alpha chains purified from denatured collagens also stimulated MCF production. Using cells from patients with rheumatoid arthritis, type II collagen stimulated production of all three factors in the presence of polymyxin B or fibronectin-depleted serum, suggesting, respectively, that neither endotoxin nor fibronectin were responsible for their generation. Monocytes, purified from normal blood by an adherence technique, but not lymphocytes depleted of monocytes, released MCF and PGE2 when cultured with type II collagen. These results demonstrate that collagens can act as ligands to stimulate monocytes, as well as antigens to stimulate sensitized lymphocytes, to produce soluble factors that may contribute to the destruction of connective tissue.
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PMID:Collagens act as ligands to stimulate human monocytes to produce mononuclear cell factor (MCF) and prostaglandins (PGE2). 630 48

To develop techniques for studying transport properties and secretory function of selected cell types in the gastric mucosa, separated fractions of dispersed canine fundic mucosal cells were placed in short-term culture to form epithelial monolayers. Cell fractions enriched in either chief, parietal, or mucous cells were prepared by using counterflow centrifugation and were plated on type I collagen. An epithelial monolayer formed by approximately equal to 36 hr. Immunofluorescence with an antipepsinogen I antibody revealed pepsinogen-containing granules in greater than 95% of the cells, regardless of whether the monolayers were formed from the mucous, chief, or parietal cell-enriched fractions. Upon achieving confluency, chief cell monolayers were mounted in Ussing chambers to study their electrical properties. Under basal conditions, monolayers (n = 6) had a spontaneous potential difference (PD) (+/- SEM) of 26 +/- 4 mV (apical surface negative), a short-circuit current (Isc) (+/- SEM) of 16 +/- 2 microA/cm2, and a transepithelial resistance (R) (+/- SEM) of 1,480 +/- 210 omega X cm2. Histamine increased the short-circuit current, an effect blocked by an H2-receptor antagonist. Seventy percent of the spontaneous PD was amiloride sensitive, suggesting sodium absorption accounted for a major component of the PD. These preparative techniques yield highly enriched chief cell monolayers, which maintain morphological and functional cellular differentiation for greater than 48 hr in culture, thus allowing study of oriented functions of a selected cell type. The present studies indicate that an H2 receptor enhances electrogenic ion transport in chief cell monolayers, indicating that histamine can act on fundic mucosal cells other than just parietal cells.
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PMID:Electrical effects of histamine on monolayers formed in culture from enriched canine gastric chief cells. 675 24

Serum concentrations of insulin-like growth factor I (IGF-I) and insulin-like growth factor binding protein 3 (IGFBP-3), the carboxyterminal propeptide of type I collagen (PICP), the carboxyterminal pyridinoline crosslinked telopeptide of type I collagen (ICTP), and the aminoterminal propeptide of type III procollagen (PIIINP) were studied in 10 prepubertal children with asthma (mean age 9.0 years). The children were treated with 2.5 and 5.0 mg/day prednisolone in a randomised double blind crossover trial with run in, treatment, and washout periods of two weeks. No statistically significant effects on serum concentrations of IGF-I and IGFBP-3 were found. Dose related reductions of PICP, ICTP, and PIIINP were observed: the mean (SEM) reduction in PICP was 33.4 (26.3) and 68.4 (20.6) micrograms/l, in ICTP 2.5 (0.5) and 2.9 (0.6) micrograms/l, and in PIIINP 2.1 (0.7) and 3.1 (1.8) micrograms/l during the 2.5 and 5.0 mg prednisolone periods respectively. Short term treatment with low daily doses of prednisolone is associated with suppression of serum markers of type I and III collagen turnover in children with asthma. Intermediate and long term effects remain to be studied.
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PMID:The insulin-like growth factor axis and collagen turnover during prednisolone treatment. 752 81

We measured bone mineral density (BMD) using dual-energy x-ray absorptiometry in 20 patients with Cushing's syndrome (CS) (14 pre- and 2 postmenopausal women, 4 men) before and in 18 of them also at regular intervals after surgical cure (median duration of follow-up, 36 months). In addition, in the premenopausal women with CS, fasting blood samples and 2-h fasting urine samples for measurement of biochemical parameters of bone and collagen metabolism were collected before and in 9 of them also at regular intervals during the first 2 yr after surgery. Marked osteopenia was present in most patients with active CS (Z-scores: lumbar spine -1.45 +/- 1.44 and femoral neck -1.50 +/- 1.02; mean +/- SD). No consistent change in BMD was observed at 3 and 6 months after surgery. Thereafter BMD increased considerably in almost all patients. For the 15 patients with a follow-up of at least 1 yr, Z-scores at the last evaluation were -0.65 +/- 1.27 for the lumbar spine and -0.98 +/- 1.02 for the femoral neck (both P < 0.002 compared with pretreatment values). In the premenopausal patients, the increase in BMD both in the lumbar spine and in the femoral neck at 24 months was inversely correlated with age (r = -0.733, P < 0.03, and r = -0.667, P < 0.05, respectively). Serum levels of osteocalcin, bone alkaline phosphatase, carboxyterminal propeptide of type I procollagen, aminoterminal propeptide of type III procollagen, and the cross-linked telopeptide of type I collagen were not significantly different between the group of 14 premenopausal patients with active CS and a control group of 18 age-matched healthy premenopausal women. However, the urinary hydroxyproline/creatinine ratio was significantly higher in patients with CS (24.6 +/- 9.6 vs. 16.2 +/- 3.5 mumol/mmol, P < 0.01). In all 9 premenopausal patients, serum levels of osteocalcin increased considerably between 0 and 3 months (from 1.04 +/- 0.20 to 3.82 +/- 0.30 nmol/L) (mean +/- SEM, P < 0.0001), indicating a prompt increase of osteoblast activity. Also serum levels of carboxyterminal propeptide of type I procollagen, aminoterminal propeptide of type III procollagen, and cross-linked telopeptide of type I collagen, and the urinary hydroxyproline/creatinine ratio increased significantly between 0 and 3 months. Thereafter these levels decreased gradually. We conclude that marked osteopenia in the lumbar spine and femoral neck is present in most patients with active Cushing's syndrome.(ABSTRACT TRUNCATED AT 400 WORDS)
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PMID:Bone mineral density and bone turnover before and after surgical cure of Cushing's syndrome. 755 64

PTH has been postulated to play a role in both nocturnal and age-related increases in bone resorption. We tested this hypothesis directly in 10 young (ages 24-35 yr) and 10 elderly (ages 71-78 yr) normal women by measuring the cross-linked N-telopeptide of type I collagen (NTx), a marker for bone collagen breakdown, in 4-h urine collections before and during suppression of PTH secretion by a 24-h iv infusion of calcium. Serum ionized calcium and PTH levels were also measured every 2 h before and during the infusion. In both groups of women, serum PTH levels and urinary NTx excretion followed a circadian pattern before calcium infusion (analysis of variance, P = 0.0001) with peaks in the afternoon and at night for PTH and at night for urinary NTx. During the calcium infusion, the nocturnal urinary NTx excretion peak persisted (P = 0.0001), despite elimination of both PTH peaks. Urinary 24-h NTx excretion (nanomoles per millimoles of creatinine) at baseline was higher in the elderly women (mean +/- SEM, 25.7 +/- 2.1) than in the young women (19.3 +/- 1.7) (P < 0.01), and the decrease during calcium infusion was greater (7.5 +/- 1.9 vs. 4.1 +/- 1.5, P < 0.05). Therefore, the increase in serum PTH levels with age is one of the major factors responsible for the age-related increase in bone resorption. PTH does not mediate the circadian pattern of bone resorption but does play a role in setting the absolute level of bone resorption at which this pattern occurs.
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PMID:Role of parathyroid hormone in mediating nocturnal and age-related increases in bone resorption. 759 43

We describe the synthesis of a new, porous, modified bioactive glass for use as a template for bone formation in vitro. The porosity of the glass was 36.4%; the pore size ranged from 10-160 mm, and there was no incipient devitrification. Prior to seeding the glass with cells, it was necessary to condition the disks. Optimum conditioning was achieved by immersing the templates in a tris buffer at pH 6.8 for 48 h and then treating the glass with tissue culture medium for 1 h at 37 degrees C. The conditioned glass disks were seeded with 10(6) neonatal rat calvaria osteoblast-like cells; cells on the substrate were maintained in culture for 3-7 days. To prevent pH shifts due to corrosion of the conditioned glass, the medium:glass ratio was maintained at 90 ml/g. We found that the templates were rapidly invaded by cells which maintained the osteoblast phenotype; thus, they exhibited high alkaline phosphatase activity and synthesized type I collagen and osteocalcin. SEM-EDAX showed that the cells elaborated substantial amounts of extracellular matrix and a bonelike tissue was present throughout the entire template thickness. FTIR analysis of material formed in the glass indicated that the mineral phase was a biologic hydroxyapatite. Controls (cells without substrate and substrate without cells) exhibited none of these features. Results of the study suggest that this porous glass can function as a template for generating bone in vitro.
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PMID:Bioactive material template for in vitro synthesis of bone. 761 87

A total of 126 gingival crevicular fluid (GCF) samples were collected from 20 adults using paper strips. Patients were divided into a periodontitis-affected group (13 subjects) and a periodontitis-free group (7 subjects) by pocket depth and radiological bone loss. 4 subjects from the periodontitis-affected group received a single episode of periodontal treatment (scaling, root planing and curettage) and GCF samples were collected 2, 5, 10, 20 and 40 days after treatment. Type I collagen carboxyterminal telopeptide (ICTP) in GCF was extracted into saline solution and determined by a radioimmunological method. Mean GCF ICTP concentration was 425 micrograms/l (SEM 45) in periodontitis patients and 148 micrograms/l (SEM 25) in periodontitis-free subjects, i.e., GCF ICTP concentrations were about 100 x higher than serum reference values. Significant positive correlations were found between GCF ICTP total amount per site and plaque index (R = 0.362), papilla bleeding index (R = 0.259), pocket depth (R = 0.464) and radiological bone loss (R = 0.418). Periodontal treatment decreased GCF ICTP concentration to the level seen in healthy subjects. However, large variations were seen between subjects and sites. ICTP levels below the detection limit were often found in deep pockets, as well as high values in periodontitis-free subjects. It was concluded that GCF ICTP reflects the local type I collagen degradation in periodontal tissues, and probably gives information about the tissue destruction process beyond the reach of the clinical parameters.
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PMID:Type I collagen carboxyterminal telopeptide in human gingival crevicular fluid in different clinical conditions and after periodontal treatment. 803 76

Type I collagen makes up more than 90% of bone matrix. Therefore, analysis of antigens related to collagen formation and degradation in bone should provide good and specific estimates of both bone resorption and bone formation rates. In this study we measured serum levels of the pyridinoline cross-linked telopeptide domain of type I collagen (ICTP) as a marker of bone resorption and serum carboxy-terminal propeptide of type I procollagen (PICP) as a marker of bone formation. Serum levels of the two antigens were correlated to histomorphometric indices of bone resorption and bone formation calculated from iliac crest bone biopsies in a group of 18 individuals with high- and low-turnover bone disease (myxedema, primary hyperparathyroidism, and thyrotoxicosis). After logarithmic transformation the regression of S-ICTP on volume-referent resorption rate (BRs/R/BV) was significant (r = 0.61, p < 0.01, SEM/Y = 56%). S-ICTP also showed a significant regression on the volume-referent cancellous bone balance (r = -0.45, p < 0.05, SEM/Y = 412%). S-PICP was significantly correlated to the mineral appositional rate (r = 0.53, p < 0.05) and volume-referent bone formation rate (r = 0.61, p < 0.01, SEM/Y = 48%). The correlation to bone turnover as expressed in the activation frequency was also highly significant (r = 0.61, p < 0.01, SEM/Y = 51%). No significant correlation with wall thickness or bone balance was demonstrable per remodeling cycle. Thus, assays employing antigens that reflect collagen formation and degradation are useful instruments for the evaluation of rates of bone remodeling in metabolic bone disease.
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PMID:Serum markers of type I collagen formation and degradation in metabolic bone disease: correlation with bone histomorphometry. 844 31


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