Cystatin C, and inhibitor of bone resorption produced by osteoblasts

Spermatozoa embedded in the outer perivitelline layer and points of hydrolysis (holes) produced by spermatozoa in the inner perivitelline layer of chicken and turkey eggs were found to be evenly distributed and linearly correlated (r = 0.80 for both species) throughout the layers from most regions of the egg, except from those directly over the germinal disc, in which there were more holes. In turkey eggs there appeared to be relatively fewer perivitelline spermatozoa, since many had degenerated beyond recognition. In eggs from both species, there were approximately 25 times more holes mm-2 in the inner perivitelline layer from over the germinal disc region than that from other regions of the egg. The relationship between these two frequencies could also be described as linear (r = 0.81 for chicken and 0.78 for turkey eggs), although there was some evidence for a saturation effect for holes over the germinal disc. The fertile status of eggs was shown to be a function of all of the above parameters. Eggs from both species had a 50% probability of being fertile when around 3 spermatozoa penetrated the inner perivitelline layer over the germinal disc and showed maximum fertility when more than 6 spermatozoa penetrated this region. Spermatozoa in the outer perivitelline layer and holes in the inner perivitelline layer from regions other than over the germinal disc could also be used to predict fertility, although with less certainty. Since the number of spermatozoa interacting with the egg reflects the numbers of those stored in the uterovaginal sperm storage tubules, the relationships derived in this work should be useful for understanding how fertility in chickens and turkeys is a function of oviducal sperm storage and transport.     

Absorption: Nature, assessment, and correlates.

This article reviews theoretical and empirical work on absorption and the relationship of absorption with selected variables. Absorption is defined as a characteristic that involves an openness to experience emotional and cognitive alterations across a variety of situations. The nature and assessment of absorption and the relationship of absorption with (a) hypnosis and hypnotizability, (b) imagery, daydreaming, and consciousness, and (c) attentional processing and psychophysiological responding are considered. Conceptual and methodological issues are examined, and directions for future research are specified. Absorption is argued to be central to an understanding of the nature of subjective experience as well as to aspects of cognition and behavior. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Contrast medium resorption in ERCP

During this study the absorption rates of two contrast media were measured in double-blind design. 33 patients received lopamidol (Solutrast 300), and 30 patients Meglumine iothalamate (Conray 60). A regular absorption of the contrast media during ERC, ERP and ERCP could be stated. With reference to the absorption rates a slight, but for statistically not significant advantage for the contrast medium lopamidol could be ascertained. During ERC the absorption rates ranged from 0.4 to 30%, during ERP from 2.2 to 18.8% and during ERCP from 1.0 and 30.0%. Consequently the endoscopist always has to take into account an anaphylactoid reaction due to the systemic absorption of contrast media which, compared to other examinations with contrast media, happens relatively seldom.     

Phosphorus deficiency, parathyroid hormone and bone resorption in the growing rat

Sham-operated and parathyroidectomized (PTX) rats were divided into two pair-fed groups, one on a normal mineral intake (0.5% Ca, 0.3% P), the other on a regimen low in phosphorus (0.5% Ca, 0.03% P). P depletion led to a drop in plasma P and urine P, a rise in plasma Ca and a marked rise in urine Ca, a drop in serum magnesium and a rise in urine Mg. The changes were more pronounced in the PTX animals, but final values were the same in both groups. Parallel bone-seeking isotope (85Sr, 177Lu, 237Np) studies in nonablated animals revealed an increase in the urinary nuclide output and in the urine/tibia ratio in P-deficient animals. Normal and primary bone osteocytes decreased and enlarged osteocytes increased as a result of P deficiency; osteoclasts and osteoblasts also increased. Bone composition showed a drop in ash content and a rise in water, with a light decrease in both Ca and P, and a corresponding rise in hydroxyproline and nitrogen in the P-deficient animals. The results are interpreted to mean that P-deficiency in the young growing rat leads to an increase in bone resorption which occurs also in the absence of parathyroid hormone (PTH). The fact that final values were similar in the control and PTX P-deficient animals suggests that steady-state regulation can also occur without PTH. Because P-deficiency leads to rapid hypercalcemia and rapid marked hypercalciuria, there may exist a mechanism for phosphate regulation which would then supersede Ca homeostasis. The change in serum and urine Mg levels may reflect a decrease in tubular Ca and Mg reabsorption associated with P-deficiency.     

Effects of hormone replacement therapy in bone resorption, in post-menopausal women

BACKGROUND: The effects of different therapies on bone loss rate can be measured using biochemical markers of bone resorption such as urinary hydroxyproline. AIM: To study the effects of hormone replacement therapy on urinary hydroxyproline in postmenopausal women. PATIENTS AND METHODS: Eighty three postmenopausal women without hormone replacement therapy, 54 postmenopausal women receiving hormone replacement therapy and 16 premenopausal women (considered as the control group) were studied. Hydroxyproline was measured in an early morning urine sample, after one day of diet without meat or gelatin. RESULTS: Urinary hydroxyproline in premenopausal women was 33.7 +/- 7.9 mg/g creatinine. The figure for postmenopausal women with hormonal replacement therapy was 33.7 +/- 5.9 mg/g creatinine. Postmenopausal women without replacement therapy had an urinary hydroxyproline of 47.4 +/- 8.5 mg/g creatinine, significantly higher than that of premenopausal and supplemented women. In 21 postmenopausal women, hydroxyproline was measured before and after three months of replacement therapy, values decreased 35.5 +/- 11% in this period and there was a direct correlation between initial values and the degree of reduction (r = 0.69, p < 0.001). CONCLUSIONS: Postmenopausal women receiving hormone replacement therapy have a urinary hydroxyproline excretion similar to that of premenopausal women.     

Macrophage activation results in bone resorption

Monocytes or macrophages from important accessory cells in the regulation of bone metabolism and destruction. Cells of the mononuclear phagocyte lineage form the precursor cells of the osteoclasts. Soluble products produced by activated macrophages regulate progenitor cell proliferation, recruitment, differentiation, and activity of osteoblasts and osteoclasts. After osteoclasts are removed from the resorption site, macrophages process bone surfaces and create a cement line before osteoblasts enter to form new bone. Although osteolysis associated with normal bone remodeling is seen as an osteoclast driven process, it may be that in chronic inflammation macrophage activation and vascular derangements lead to low pH, local bone demineralization (acid attack), and H+ mediated stimulation of the primary afferent nociceptive nerve fibers (bone pain). Osteoclasts are not able to attach to demineralized bone or to osteoid surfaces. However, if macrophages degrade the demineralized organic bone matrix, chemotactic factors and attachment sites for osteoclasts are produced. In such a scenario, the osteoclast-osteoblast mediated activation, resorption, and formation cycle would be secondarily activated. Such events may play a role in the most common orthopaedic problem related to macrophage activation, aseptic loosening of orthopaedic joint implants, which is secondary to a chronic foreign body reaction and to micromovement.     

Pharmacologic inhibition of particulate-induced bone resorption

The traditional hospital-based approach to Australian nurse education curricula was primarily based on the medical model and directed towards the preparation of nurses who were able to give care to individual clients. The major focus was on the needs of the individual. A notable absence in curricula was any consideration of the role or importance of families to individual and family health. This was despite the continuing involvement that nurses have in their practice with the families of their clients. This paper describes the experiences of introducing a family nursing subject in an undergraduate, preregistration nursing programme which focuses on the family as a unit of care. Educational strategies, clinical experiences, and evaluation of the unit of study are discussed.     

Absorption, excretion, and tissue deposition of titanium in sheep

Titanium metabolism was measured in three 18 kg lambs each fed 450 g chopped hay daily. Two of the lambs were dosed orally and one intravenously with 3 muCi titanium-44 each. Clearance of the intravenous dose was extremely slow; after oral administration, however, no titanium-44 was detected in blood plasma for 48 h. Over 96% of the oral dose was recovered in feces and digestive tract contents. Titanium-44 absorption, estimated from total carcass recovery and by comparison of concentrations in internal organs of orally and intravenously dosed lambs, was less than .5%. Fecal titanium could be a satisfactory index of soil ingestion by grazing ruminants.     

Effects of the bisphosphonate tiludronate on bone resorption, calcium balance, and bone mineral density

Bone resorption inhibitors, such as bisphosphonates, are potentially useful in treatments aimed at increasing bone mass. Among bisphosphonates, tiludronate has proven efficacious in preventing bone loss in postmenopausal women. However, it is not clearly established whether bisphosphonates are more potent when given intermittently or continuously. We investigated the effects of tiludronate on (1) retinoid-stimulated bone resorption in thyroparathyroidectomized rats, (2) calcium balance in intact rats, and (3) bone mineral density (BMD) as measured by dual-energy x-ray absorptiometry at the levels of the lumbar spine, tail, and tibia in 6-month-old rats made osteoporotic by ovariectomy (OVX), in which an intermittent cyclic schedule of treatment was compared to continuous administration. Tiludronate induced a dose-dependent decrease in retinoid-stimulated bone resorption. It increased the intestinal absorption and body retention of calcium. In OVX rats it caused a time- and dose-dependent increase in BMD at the level of the three investigated sites, the effects being maintained for at least 8 weeks after the end of therapy. Continuous and intermittent cyclic regimens appeared to induce similar increases in BMD. These results indicate that tiludronate is efficacious in decreasing bone resorption and increasing calcium balance and bone mineral density in rats.     

Diagnosis and treatment of extracanal invasive resorption

Extracanal invasive resorption is not a well-defined phenomenon. This article describes its clinical, radiographic, and histological characteristics. Treatment of affected teeth based on the location of the resorptive defect is also described.     

Participation of cathepsin L on bone resorption

The proteinase responsible for bone collagen degradation in osteo-resorption was examined. The bone pit formation induced by parathyroid hormone (PTH) was markedly suppressed by leupeptin, E-64 and cystatin A, while no inhibition was observed by CA-074, a specific inhibitor of cathepsin B. Pig leucocyte cysteine proteinase inhibitor (PLCPI), a specific inhibitor of cathepsin L, and chymostatin, a selective inhibitor of cathepsin L, completely inhibited the pit formation. Cathepsin L activity in osteoclasts was much higher than the other cathepsin activities. Serum calcium in rats placed on a low calcium diet was decreased by treatment of E-64 or cystatin A, but not by CA-074. These findings suggest that cathepsin L is the main proteinase responsible for bone collagen degradation.     

Apical root resorption in orthodontically treated adults

This study analyzed the relationship in orthodontically treated adults between upper central incisor displacement measured on lateral cephalograms and apical root resorption measured on anterior periapical x-ray films. A multiple linear regression examined incisor displacements in four directions (retraction, advancement, intrusion, and extrusion) as independent variables, attempting to account for observed differences in the dependent variable, resorption. Mean apical resorption was 1.36 mm (sd +/- 1.46, n = 73). Mean horizontal displacement of the apex was -0.83 mm (sd +/- 1.74, n = 67); mean vertical displacement was 0.19 mm (sd +/- 1.48, n = 67). The regression coefficients for the intercept and for retraction were highly significant; those for extrusion, intrusion, and advancement were not. At the 95% confidence level, an average of 0.99 mm (se = +/- 0.34) of resorption was implied in the absence of root displacement and an average of 0.49 mm (se = +/- 0.14) of resorption was implied per millimeter of retraction. R2 for all four directional displacement variables (DDVs) taken together was only 0.20, which implied that only a relatively small portion of the observed apical resorption could be accounted for by tooth displacement alone. In a secondary set of univariate analyses, the associations between apical resorption and each of 14 additional treatment-related variables were examined. Only Gender, Elapsed Time, and Total Apical Displacement displayed statistically significant associations with apical resorption. Additional multiple regressions were then performed in which the data for each of these three statistically significant variables were considered separately, with the data for the four directional displacement variables. The addition of information on Elapsed Time or Total Apical Displacement did not explain a significant additional portion of the variability in apical resorption. On the other hand, the addition of information on Gender to the information on the four directional displacement variables yielded an R2 value of 0.35, which indicated that these variables taken together could account for approximately a third of the observed variability in apical resorption in this sample.     

Osteoid resorption by mononuclear cells in vitro

For the first time, mononuclear cell-mediated ingestion of osteoid in cultures of long bones of fetal rats is described and characterized. The mononuclear cells, located at sites of osteoid deposition, ingest collagen fibrils and clumps of mineral crystals which are segregated within cytoplasmic vacuoles or multivesicular bodies. The ingestion of osteoid continues in cultures treated with agents that normally inhibit osteoclastic bone resorption. Morphologically, the osteoid-containing cells are characterized by a moderate number of mitochondria and short-stranded rough endoplasmic reticulum, a modest Golgi apparatus and variable numbers of vesicles, vacuoles, and multivesicular bodies. The morphologic appearance of the mononuclear cell is consistent with that of a macrophage.     

Absorption, tissue distribution, and excretion of zinc acexamate in rats

AIM: The SRK II formula has been widely used for intraocular lens (IOL) power calculations. The predictability of this formula is evaluated in axial myopic patients. METHODS: Planned extracapsular cataract extraction and posterior chamber IOL implantation (PECCE + IOL) were performed on 98 eyes of 98 patients with axial length > 24.5 mm. Cases had no preoperative complications and postoperative visual acuity was at least 0.5 (Snellen). Corneal refractive power and axial length were measured preoperatively and emmetropic IOL power calculations were made using the SRK II formula. Long-term (mean 4.7 months) visual acuities and refractions were noted postoperatively. RESULTS: The absolute refractive error was < 1.00 Diopters (D) in 57 eyes (58.2%) and < 2.00 D in 83 eyes (84.7%). The mean absolute error of the SRK II formula in axial myopia was 1.16 D +/- 0.78 SD. CONCLUSIONS: The SRK II formula is not very accurate in axial myopic patients.     

Subattachment inflammatory root resorption: treatment strategies

Attempts have been made to classify root resorption according to its etiology in order to develop more efficient strategies for its treatment. This condition has been identified as resulting from damage to the protective attachment layer (predentin or precementum) of the root combined with inflammation adjacent to the root surface. This article demonstrates a series of treatment strategies focused on the reversal of each manifestation of subattachment root resorption, specifically emphasizing defects that extend apically and localized defects.     

Rapid bone resorption adjacent to hydroxyapatite-coated implants

This paper describes rapid bone resorption in the peri-implantitis of HA implants based on both our clinical observations of and histological research on extracted dense hydroxyapatite (HA) implants. The surfaces of extracted HA implants were rough, although they were smooth at fixture placement. Plaque formed on the necks of the implants, whereas little plaque was seen on the bottoms. The plaque consisted of cocci and rods, including filamentous bacteria. Few spirochetes were observed. Although surrounding bone was formed rapidly around the HA implant, bone thickness gradually decreased compared with the titanium implant. These facts suggest that the rigid biointegration of HA with the thin surrounding bone--that is, the overstressing of the bone--causes rapid bone resorption rather than plaque accumulation on HA.