Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0851184 (thinning)
 11,252 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

We recently reported that mice treated with 1,25-dihydroxyvitamin D3 ( 1,25-(OH)2D3) or 19-nor-1,25-(OH)2D2 experienced a severe loss of their thymocytes and decreased proliferation in response to concanavalin A mitogen. The present study investigated the effect of short-term treatment with 1,25-(OH)2D3 on the thymic architecture and thymocyte subsets. Daily treatment with 1,25-dihydroxyvitamin D3 at 20 ng per mouse for 4 days induced significant involution of thymic tissue. The atrophy was predominantly observed in the cortical component. Flow cytometric analysis of thymocyte subsets showed that the CD4 + CD8 + population was the primary target. Since the treated mice experienced profound hypercalcemia, we studied the effect of 1,25-(OH)2D3 on animals fed a vitamin D-deficient, low calcium diet or the same diet containing vitamin D for 25 days prior to treatment. The low calcium fed mice showed severe hypocalcemia and slight thinning of thymic cortex. Treatment with 1,25-(OH)2D3 moderately improved the hypocalcemia but had no further effect on the thymus of these animals. On the other hand, hypercalcemia and thymic atrophy were found in the animals fed the diet containing vitamin D. Overall, the atrophy effect on the thymus caused by 1,25-(OH)2D3 treatment was prevented by eliminating the hypercalcemia observed in + D + Ca treated animals. Thus, thymic atrophy probably resulted from hypercalcemia and not from 1,25-(OH)2D3 itself.
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PMID:Effect of 1,25-dihydroxyvitamin D3 on mouse thymus: role of extracellular calcium. 860 Sep 85

Although granulocyte colony-stimulating factor (G-CSF) was originally isolated as an activity for the growth and differentiation of cells in granulocytic lineage, it has been gradually accepted that G-CSF may have a function on a wide variety of cells besides granulocytes. To elucidate the function of G-CSF on bone cells in vivo, we examined the bone tissue of transgenic mice that overexpress G-CSF. Transgenic mice express human G-CSF at an elevated level (1041 +/- 242 pg/ml in sera) under the direction of SRalpha promoter. We performed radiographic, routine histologic, and histomorphometric analyses of the bone tissue and serum biochemical assay. Nontransgenic littermates were examined as age-matched, wild-type controls in all experiments. Radiographic analysis revealed cortical thinning accompanied by enlarged bone marrow cavities in both vertebral bodies and long bones. Histologically, a decreased number and thickness of trabecular bones and cortical thinning were observed in lumber vertebrae as well as in femur specimens. The enlarged bone marrow cavities exhibited an increased number of mature neutrophilic granulocytes without apparent changes in other types of cells. The static and dynamic parameters reflecting bone resorption were found to be significantly increased in the transgenic mice. By contrast, no significant differences were detected in the parameters reflecting bone formation. Transgenic mice and littermate controls had similar serum calcium, phosphorous, and alkaline phosphatase levels. However, the serum osteocalcin level was significantly higher in transgenic mice. These findings indicate that G-CSF-expressing transgenic mice developed osteoporosis because of increased osteoclastic activity. Collectively, G-CSF could have a negative influence on bone homeostasis in vivo.
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PMID:Overexpression of the granulocyte colony-stimulating factor gene leads to osteoporosis in mice. 860 92

Calcium phosphate ceramic coatings with a hydroxyapatite chemistry applied on the surface of dental implants eliminate the need for initial mechanical retention and decrease the time necessary for bonding the implants to the bone. Hydroxyapatite-coated implants retrieved from patients were found to be compatible and to have bonded strongly to the bone, but the coatings showed thinning because of partial or total loss of coating material. This study compared the behavior in bone of newly developed fluorapatite and heat-treated hydroxyapatite coatings, with the clinically used hydroxyapatite coatings used as controls in experimental studies in dogs. The biologic responses to fluorapatite and heat-treated hydroxyapatite coatings were the same as those to hydroxyapatite coatings, and bone condensation around all coatings was histologically evident. However, the coating thickness of the fluorapatite and heat-treated hydroxyapatite coatings remained stable with only minor changes during the observation period of 24 months.
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PMID:Behavior of calcium phosphate coatings with different chemistries in bone. 863 37

We evaluated the radiological, biochemical and growth hormone (GH)/insulin-like growth factor-I (IGF-I) changes in 10 children with severe protein-energy malnutrition (PEM) who had rachitic manifestations (group 1), 10 children with severe PEM without clinical signs of rickets (group 2), and 10 children with normal body weight-for-length and -age, suffering from vitamin-D-deficiency with signs of florid rickets (group 3) and 10 normal age-matched children (group 4). Serum calcium (Ca2+), phosphorus (PO4), and albumin concentrations were markedly decreased in the two groups with PEM. Malnourished children with rickets had significantly higher serum alkaline phosphatase (ALP) concentrations compared to the malnourished group without rachitic manifestations. Radiological evaluation of the two groups who had rachitic manifestations revealed demineralization of long bones, thinning of the bony cortex, increased formation of osteoid tissue, and metaphyseal changes including cupping, fraying, and flaring. The incidence of these radiological findings did not differ among the well-nourished and the malnourished groups with clinical signs of rickets. However, the incidence of fracture of the shaft was higher (40 per cent) in the malnourished group compared to the well-nourished group (10 per cent) with rickets. In the malnourished group without clinical evidence of rickets, demineralization and cortical thinning was detected in 40 per cent without significant metaphyseal changes. Basal concentrations of GH and peak GH response to clonidine were significantly elevated and IGF-I concentrations were significantly depressed in the malnourished groups v. the other two groups. There were no significant differences in the fasting and the clonidine provoked GH levels or IGF-I concentrations between the rachitic children (group 3) and the normal children. These data suggest that in rachitic children there is not a major role for circulating GH (and by implication IGF-I) on bone mineralization. However, during malnutrition decreased IGF-I production can slow or stop epiphyseal growth and might contribute to the demineralization of the cortex of long bones.
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PMID:Radiological, biochemical, and hormonal changes in malnourished children with rachitic manifestations. 882 Jun 18

Hip fractures in men account for one third of all hip fractures and have a higher mortality than in women. The public health burden will increase as the increase in the numbers of elderly men in the community increases. In addition, the age-specific incidence of hip fractures may be increasing in some, but not all, countries. Vertebral fractures may be a public health problem as recent studies suggest that the prevalence in the community is 20-30%, similar to that reported in women. Forearm fractures should probably not be regarded as a public health problem. Peak bone mass is higher in men than women because men have bigger bones. Peak bone mineral density is the same. The amount of trabecular bone lost at the spine and iliac crest during ageing is similar in men and women. Cortical bone loss is less in men because endocortical resorption is less and periosteal formation is greater. Bone loss accelerates in elderly men because endocortical resorption and increasing cortical porosity increase the surface available for resorption. Bone fragility is less in men than women because: (a) the cross-sectional surface of the bone is larger; (b) trabecular bone loss is less as a percentage of the higher peak bone mass; (c) trabecular bone loss occurs by thinning rather than perforation; and (d) periosteal appositional growth compensates for endocortical resorption by maintaining the bending strength of bone. Reduced BMD in men with fractures may be due to reduced peak bone size and mass, and bone loss. Bone loss occurs by reduced bone formation. Whether men with fractures have increased bone fragility due to reduced periosteal appositional growth during ageing is unknown. The age-related decline in testosterone, adrenal androgens, growth hormone, and insulin-like growth factor 1 may contribute to reduced bone formation and bone loss. Men with vertebral fractures often have hypogonadism or illnesses with few clinical features that should be considered with a high index of suspicion (alcoholism, myeloma, malabsorption, primary hyperparathyroidism, haemochromatosis, Cushing's disease). Secondary hyperparathyroidism may contribute to bone loss by activating bone turnover and so increasing the number of bone remodelling units with impaired bone formation in each. There is no proven treatment for osteoporosis in men because there have been no trials using anti-fracture efficacy as an end point. Testosterone replacement should be considered in men with proven hypogonadism and vitamin D deficiency should be corrected if present. Calcium supplements and bisphosphonates are reasonable options given the lack of information.
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PMID:Osteoporosis in men. 936 40

A method for controlling the contact of cell-surface receptors with immobilized ligands has been developed. Cells are trapped in an asymmetric liquid film that can be quantitatively thinned by reducing the film's capillary pressure. Ligands adsorbed to the liquid-solid interface are forced into increasingly tighter contact with the cells as the air-liquid interface is drawn down. Controlling the degree of thinning allows study of repulsive forces, and controlling its time course produces a definite time 0 for analyzing signal transduction. This system was tested by examining the time course of calcium mobilization in T cells upon activation with anti-CD3 antibody at different dilutions and ionic strengths. The averaged calcium transient of the responding cells was essentially the same for each condition. However, the fraction of responding cells decreased with anti-CD3 dilution, and indicated that the critical ligand density for T cell activation lies between approximately 35 and 70 molecules of anti-CD3 per microm2. Decreasing the medium's ionic strength from the normal value of 157 mM to 57 mM did not affect either the average calcium response profile or the fraction of responding cells, but strongly affected receptor-ligand contact, decreasing the percent of spontaneous activation from 38% to 5%. Such an imposed decrease sets the stage for film thinning to impose much greater control of receptor-ligand contact.
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PMID:Controlling receptor-ligand contact to examine kinetics of T cell activation. 939 52

Minoxidil is the most used drug with proved effects in the treatment of androgenetic alopecia (AGA), but little is known about its pharmacological activity and target cells in hair follicles. As AGA is characterized by follicle atrophy, accelerated hair cycles and hair fiber thinning, we postulated that keratinocyte proliferation/differentiation is affected and we tested Minoxidil's effects on those parameters. Normal human keratinocytes (NHK) of follicular or epidermal origin were cultured in the presence of Minoxidil (0, 0.1, 1, 10, 100, 1,000 microM) during 5-8 days in various media (high-/low-calcium content, with or without serum). Proliferation was assessed by mitochondrial dehydrogenase activity (XTT), BrdU incorporation, lysosome numeration (neutral red incorporation) and total protein dosage. Drug-induced cytotoxicity was measured by lactate dehydrogenase release in culture supernatant, and pro-differentiating effects were evaluated by relative involucrin expression (ELISA dosage). On this basis, we showed that Minoxidil had biphasic effects on the proliferation and differentiation of NHK: Minoxidil stimulated NHK proliferation at micromolar doses, while antiproliferative, pro-differentiative and partially cytotoxic effects were observed with millimolar concentrations. We can hypothesize that Minoxidil hypertrichotic activity in vivo is possibly mediated by the maintenance of proliferative potential in follicular keratinocytes precociously committed to differentiation.
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PMID:Biphasic effects of minoxidil on the proliferation and differentiation of normal human keratinocytes. 941 95

1. The focus of this review is the effects and mechanism of action of p,p'-DDE on eggshell formation in birds. Inhibition of prostaglandin synthesis in the eggshell gland mucosa is a probable mechanism for p,p'-DDE-induced eggshell thinning. 2. The duck is sensitive to p,p'-DDE-induced eggshell thinning but the domestic fowl is not, and studies comparing the two species in regard to the calcium and prostaglandin metabolism of the eggshell gland have shown that eggshell thinning induced by p,p'-DDE in ducks is accompanied by reduced activity of prostaglandin synthetase, reduced levels of prostaglandin E2, and reduced uptake of 45Ca by the eggshell gland mucosa. The content of calcium, bicarbonate, chloride, sodium, and potassium are also reduced in the eggshell gland lumen in ducks exhibiting eggshell thinning. None of these effects are seen in the domestic fowl. 3. Inhibition of prostaglandin synthesis is a specific effect of p,p'-DDE. The detrimental effects of p,p'-DDE on the eggshell gland seem to be unique when comparing the compound with structurally related substances, i.e., similar treatment regimens with o,p'-DDE, p,p'-DDT, o,p'-DDT, and p,p'-DDD do not cause eggshell thinning in ducks. Neither do they inhibit prostaglandin synthesis in the eggshell gland mucosa. 4. Administration of other compounds that do inhibit prostaglandin synthesis, e.g., indomethacin, does cause the same effects as those seen with p,p'-DDE, i.e., eggshell thinning and the described effects on the calcium and prostaglandin metabolism of the eggshell gland.
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PMID:DDE-induced eggshell thinning in birds: effects of p,p'-DDE on the calcium and prostaglandin metabolism of the eggshell gland. 949 Jan 82

Bone thinning causing both fractures and severe pain not associated with fractures has been recognized in patients with chronic liver diseases. The patients most commonly affected are those with primary or secondary biliary cirrhosis, but those with alcoholic liver disease and cirrhosis after active chronic hepatitis may also be involved. Chronic liver disease has also been recognized as an important cause of osteoporosis in both sexes, with the mechanism thought to be a combination of calcium and/or vitamin D. The 9.1% patients with chronic active hepatitis accompanied with osteodystrophy. But 50% cirrhotic patients accompanied with osteodystrophy. Bone densitometry was determined by Digital Image Processing Method (Osteodystrophy < mean-2SD: age- and sex-matched normal value). Serum levels of osteocalcin (BGP) and parathyroid hormone (PTH) in patients of hepatic cirrhosis without osteodystrophy were lower than those with osteodystrophy. These results were suggested that hepatic osteodystrophy was rapidly turnover osteodystrophy. To function physiologically, vitamin D must be hydroxylation in liver to 25-(OH)-D and subsequently by the kidney to 1 alfa, 25-(OH)2-D. Osteodystrophy associated with hepatic cirrhosis is due to a defect in the 1 alfa-hydroxylation by the kidney rather than a hepatic hydroxylation defect. 1 alfa OH-D3 is very useful for treatment for hepatic osteodystrophy.
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PMID:[Hepatic osteodystrophy]. 964 89

Pregnancy and lactation make demands on maternal calcium homeostasis which may affect bone strength. Recently, changes in cancellous architecture have been described in iliac crest bone biopsies from normal pregnant women but the rarity of such human material means an animal model is essential. The microanatomy of cancellous bone was compared in uniparous and multiparous rats using undecalcified histological sections of lumbar and caudal vertebrae and also proximal femora. An automated trabecular analysis system (TAS) measured a comprehensive range of structural variables including the trabecular number, connectivity and width. In the first pregnancy cycle an early stimulation of bone formation (which quadrupled at some sites) was indicated by an increase in the skeletal uptake and spacing of double calcein labels and the immediate generation of thicker more numerous and interconnected trabeculae. A 40% increase in cancellous bone volume was observed in the lumbar spine in comparison with age-matched virgin controls. In contrast, a rapid succession of 3 pregnancy cycles (including lactation) culminated in cancellous atrophy of 15% at the same site, with a loss in trabecular number ranging from 20% (caudal vertebra) to 30% (lumbar vertebrae). In comparison, the proximal femur lost 40% of its struts but, nevertheless, uniquely sustained its cancellous bone volume. When lactation was excluded the number of struts lost was halved although trabecular thinning then took place which was sufficient to maintain the previous 15% deficit in bone volume. It was concluded that a single pregnancy strengthens the cancellous component of the maternal skeleton while a quick succession of pregnancies weakens it. Lactation influences the pattern of bone loss but not its amount.
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PMID:The impact of mammalian reproduction on cancellous bone architecture. 1038 78


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