- Email: [email protected]
22. The osteogenic potential of bone marrow fibroblasts and adipocytes
Abstracts
from the Bone and Tooth Society Meeting,
September
V. Eve&l, J.M. Delaissez, W. Korperl, A. Niehofl, G. Vaes2 and W. Beersten’. ‘Exper. Oral Biology Group, Lab. ofCell Biology and Histology, Uniuersitu of Amsterdam, The Netherlands; -‘Laborutoire de Chimie Physiolog&e, Uniuersite de Louzlain and 10, UCL 75.39, Brussels, Belgium. Cysteine-proteinases (CP) and collagenase (matrix metalloproteinase 1, MMP 1) are known to participate in bone resorption. In the present study, their role was investigated at the level of the osteoclast resorption zone by evaluating the effects of selective proteinase inhibitors on the ultrastructure of that zone. Calvaria from 5 day old mice were cultured (up to 72 hr) in Medium 199 + 2.5% FCS with or without I’TH (1 U/ml), calcitonin (0.9 U/ml), the CP inhibitor E-64 (42 PM) and the MMP inhibitor Cl-l (40 PM). The explants were processed for microscopic (LM and EM) examination and morphometric analysis. In the presence of each of the two proteinase inhibitors a large area of bone matrix free of mineral was seen adjacent to the ruffled border of the osteoclasts. This area proved to be IO-times larger in inhibitortreated explants than controls (p
19. Demonstration of osteoclasts at different stages of the bone remodelling cycle: A histological and in situ biochemical study of adult human bone. R.A. Dodds, I.E. James, S. Walsh and M. Gowen. Bath Institute for Rheumatic Diseases, Trim Bridge, Bath BAZ IHD and Uniztersity of Bath. &i& studies of adult human bone are restricted by the very nature of the tissue: a hard mineralised matrix and relatively few cells per area of bone. We describe a human tissue in which there is sufficiently high bone turnover to allow the in study of human osteoclast activity at different stages of the bone remodelling cycle. Tartrate resistant acid phosphatase (TRAP) is used as a cytochemical marker of osteoclas&. Using an in biochemical method TRAP activity was measured in individual osteoclasts in cryostat sections by microdensitometry, and correlated with the location of the osteoclast within the tissue. Osteoclasts not associated with bone resorption showed two distinct populations: one with high (66.0 +/- 3.9 ; MIExlOO mean +/- SD. n=16) and one with lo’w (33.6 +/- 12.3. n=154) activity. Osteoclasts loosely associated with the bone surface but present in areas of active bone resorption demonstrated a broad spectrum of activity (49.3 +/13.1. n=128). Osteoclasts actively resorbing bone within Howship’s lacunae and often showing distinct localisation of enzyme activity towards the bone surface showed high activity (62.0 +/- 9.9. n=162). Thus we have demonstrated differential TRAP activity associated with osteoclast function at different stages of the resorptive cycle. This novel approach may therefore allow us to correlate expression of specific proteins within osteoclasts with the various stages of the osteoclast lite cycle.
20. Requirements for the differentiation of bone cells. S. Fitton Jackson and S. Bord. Strangezuays Research Laboratory, Cambridge CBl 4RN. Organ cultures of tibia1 rudiments taken from 14d chicken embryos are being used to investigate parameters involved in the differentiation of bone cells. Conditioned medium (CM) collected from feeder cultures grown in chemically- defined medium without serum over 9 days, during which numerous layers of osteogenic tissue develop to cover the underlying bone lamellae
1990
295
while osteoblasts and osteoid fill the lacunae, is being used to test the effects of CM on shafts at various stages of culture as judged by histology and measurements for alkaline phosphatase activity, SHthymidine and “5Ca uptake and the amount of calcium present. Gel electrophoresis of the CM taken at different time points shows that nearly 50% of the products from phase 1 (O-3d) are less than ZOkDa, as compared with 20-23% in CM from phases II and 111(3-6 and 69d resp:) where a dominant doublet in the 30kDa region is present. When shafts are grown for 6d in CM from either phases 11or III more osteoid is laid down and alkaline phosphatase activity is elevated by 25% (p=O.O5) over those grown in phase I CM. These results indicate that products present in CM from older cultures promote the rate of osteoblastic maturation.
21. The osteogenic ootential of neonatal porcine bone-marrow stromal cells Tn vivo. B.M. Thomusonl, N. Loverideel, M.C. Meikle*, 1. Bennett’ and 1. Triffit’. ’ ‘Bone Growth and Metabolism Unit, Rowett Research Institute, Aberdeen, lstrangeways Research Laboratory, Cambridge, ‘MRC Bone Research Laboratory, Nuffield Orthopaedic Centre, Oxford. As an alternative tissue source for skeletal research, diffusion chambers containing porcine bone-marrow fibroblasts or marrow cell suspensions (107cells/chamber) were implanted into the peritoneal cavities of nude mice for 75 days, fixed and prepared for histology. Transverse sections revealed the consistent formation of partially mineralised, cartilaginous bands (250-750pm), located next to the filters but separated from them by a thin fibrous layer. These bands gave typical metachromatic, perilacunar staining with toluidine blue and safronin-0. Mineralisation (van Kossa) was found in defined regions immediately adjacent to the membrane filter and, less frequently, in the body of the chamber, an area predominantly occupied by amorphous, acellular material. Alkaline phosphatase activity was localised both to cell layers lining between tissue types, and to isolated cells within the matrix but was not always present beside areas of mineralisation. No cells had acid phosphatase activity. oil red-0 stained occasional cells scattered throughout the chamber suggesting the existence of functional adipocytes. These results extend our observation that neonatal porcine bone marrow fibroblasts form mineralised, alkaline phosphatase positive nodules in the presence of dexamethasone and D-glycerophosphate and confirm that these cells are a valid model for investigating the mechanisms of skeletogenesis.
22. The osteogenic potential of bone marrow fibroblasts and adipocytes. J.H. Bennett, J.T. Triffitt and M.E. Owen. MRC Bone Research Laboratory, Nulfield Orthapaedrc Centre, Oxford OX3 7LD. Foetal calf serum (FCS) encourages the growth of fibroblastic colonies in marrow cell cultures. Conditions under which the adipocytic phenotype is clonally expressed in cultures of rabbit marrow cells are determined in the present study. Cloned cell populations from marrow adipocytic colonies are compared with those derived from marrow fibroblastic colonies, in terms of their potential for differentiation, by using the in culture diffusion chamber assay. 2 x 10: irradiated autologous marrow cells were used as feeder layers in medium containing FCS to obtain well spaced fibroblastic colonies suitable for ring cloning. Single adipocytic colonies were obtained by first removing non-adherent cells, washing the cultures twice and culturing the remaining adherent cells with autologous rabbit plasma as supplement. Adipocytic colonies (21) and fibroblastic colonies (28) were isolated and expanded. Eight colonies from each group provided enough cells (2 x 10s to 2 x 100) for separate implantation and culture within diffusion chambers m. Three of the eight colonies of each group formed a mixture of bone, cartilage and fibrous tissues in the
Abstracts from the Bone and Tooth Society Meeting,
296
diffusion chambers, with the rest containing fibrous tissue only or no detectable tissue. These results support the hypothesis that adipocytic, fbroblastic and osteogenic cells present in bone marrow, have a common precursor.
23. A sequence of adaptive change following mechanical loading in bone organ cultures. G. Zaman, S.L. Minter, M.J. Pead, M.J. Morgan and L.E. Lanyon. Department of Veterinary Basic Sciences, The Royal Veterinay College, University of London. Cyclic mechanical loads, producing physiological strains, were applied to 17 day embryonic chick tibiae in organ culture. The effect of loading on RNA synthesis, glucose 6-phosphate dehvdroeenase (G6PD) activity and production of type I collagen mI&A w”as investigated. Imkediateiy following Zdminutes 07 loading, there was a load magnitude-related increase in G6PD activity in periosteal osteoblasts and osteocytes. This effect was blocked bv indomethacin (IO-fiM). 24 hours following a similar period of loading there was a load magnitude-relate8 increase in the incorporation of ?H-uridine into extracted RNA. In situ hybridization studies demonstrated that 18 hours after loading type I collagen mRNA expression was increased in alkaline phosphatase positive cells. The effect was not detectable at 4 hours. The load-related increase in type 1 Collagen mRNA indicates that this model may exhibit all the steps between loading and its “osteogenic” response. Load-related increases in G6PD activity and RNA synthesis, which can be blocked by indomethacin, have previously been demonstrated in vivo and in vitrol’,2,91 and may form part of this pathway. Pead M.J. et al (1988) C&if. Mm
Res. 4: 783.788,
lissue
ht.
43: 92-96, Skerry
El Haj et al (1990) J. Bone & Mm
Both chicken and rat CGRP (c and r-CGRI’) promote plasma clearance of simultaneously administered 4iCa in chicks (1) and cCGRP promotes &Ta upta&e into bone in (2). We now report uoon the effects of r-CGRP in the chick. In 22hr fasted chicks (<00+5g), r-CGRP (1.71nMol/lOOg body wt, iv.) significantly increased bone ‘SCa uptake, peak responses 10 min after injection, were sternum (129%) and femur (118%) of control values. In a dose-resoonse curve the most effective dose at IOmin was l.l4nMdl/lUOg, while a higher dose (4,65nMol/lOOg) gave partial reversal. Bv contrast, in continuouslv fed chicks, r-CGRP (l.l4nMol?lOOg) significantly reduced label deposition into sternum (85.7%) and femur (91 .l%) of controls. Surprisingly, in 22hr fasted chicks, salmon calcitonin (4.56nMol/lOOg body wt) significantly reduced 4jCa uptake, the greatest responses, as a percentage of control values, were calvarium (82.6%), femur (64.5%) and sternum (62%). We conclude that r-CGRP, like c-CGRP, promotes h’luptake into chick bone in the heterologous peptide appears to be more potent. CGRP is also hypercalcaemic in chicks, suggesting a complex action consisting of at least two opposing effects. Regulatory
Peptides
(In press),
1990
ntzd *ICI Phnrmncelrticnls, Meresidr, Alderle!y Pnrk, Mncclesfirld. Cheshire, SK10 4TG. In man, retinoids induce adverse long bone effects including thinning, remodelling and premature epiphyseal closure. We examin:d long bonesfrom*TRA-treated rat; to quantify aspects of these effects. Twentv-five male Wistar rats were divided into 5 groups. On day (d) b, 5 rats were PM’d, the remainder being dosed orally with TRA daily at 0, lo,20or 30 mg/kg until PM (d37). The femur, tibia, fibula, humerous, radius and ulna were measured using callipers and weighed. Diaphyses were sectioned transversely in 3 positions for medullary cavity diameter and cortical bone thickness measurement. TRA did not affect body weight or bone length but induced a dose-related weight reduction in all bones. TRA also induced a dose-related reduction in diameter at mid-shaft but the effect was less marked towards the epiphyses. Although cortical bone thickness was comparable in all parts at d37, TRA induced dose-related reductions in medullary cavity diameters of all bones. The degree of this latter effect varied between bones and along their length. In all rats, diaphysis diameter generally increased from d0 to d37, but with higher levels of TRA the extent to this increase was reduced. These results show that TRA reduced periosteal depositionand increased endosteal deposition in a dose-related manner. However, there were no adverse effects on bone length increases.
26. Dietary acid-base balance and bone metabolism. H. Abu Damir, W. Buchan, J. Milne, N. Loveridge and D. Scott Rowett Research Institute, Greenburn Road, Aberdeen AB2 9SB. Scotland.
et al (1989) J. Bone &
Res. (In press).
24. A comaarison of chicken and rat calcitonin gene-related peptide (eGRP1 upon bone Wa uptake in chic&. A.K. Ancill. Z.A. Bascal. G. Whitaker and C.G. Dacke Division of bharmacology; School of Pharmacy, Portsmouth Polytechnic, Portsmouth, Hants, PO1 2DT.
A.K. Ancill et
September
Z.A. Bascall
d
(1990) Bone
(In press).
In earlier studies, growing lambs retained less calcium on diets containing ammonium chloride (NH&I) than on those containing sodium bicarbonate (NaHCO,). This study investigates the possible mechanism for this difference. Lambs (25kg) were fed diets containing either NH,Cl (log/kg; n=6) or NaHCO, (20g/kg; n=6) for 9 weeks. Radiochemical and chemical calcium balance measurements over a final 8 day period showed similar dietary calcium absorption (3.59 vs 3.20g/day) but a reduction in calcium retention (1.45 vs 2.34g/day; ~~0.05) and increased urinary calcium loss (0.97 vs 0,05g/day; p
27. Correction of vitamin D deficiencv in elderly long-stay . . patients by sunlight exposure. ’ A.R. Webb’, G.A. CampbelP, MS. Steven’ and D.J. Hosking 4. lDepartment Meteorology, Reading University, Reading RG6 2AU, *Cambridge Health Authority, Department of Geriatirc Medicine, Addenbrookes Hospital, Hills Road, Cumbridge CB2 ZQQ, IDepartment of Geography, University Park, Nottingham NG7 2RD and 4Department Medicineand Health Care of the Elderly, University Hospital, Nottingham.
of
of
25. Long bone thinning and remodelling in the rat induced by all-mretinoic acid (TRA). A.T. Keene, G.B. Willars, M.J. Tucker* and J.A. Turton. Toxicology Unif, Department of Pharmacology, The School of Pharmacy, (Utriversity ofLondon), 29-39 Brunswick Square, London WCIN 1AX
It is generally accepted that ultraviolet-B (UVB) radiation is important in maintaining an adequate vitamin D status, Darticularlv if dietan, intake is low. However, the rate of production of vitamin D in vivo and the amount of sunlight required for health have yet to be quantified. In order to study the
from the Bone and Tooth Society Meeting,
September
V. Eve&l, J.M. Delaissez, W. Korperl, A. Niehofl, G. Vaes2 and W. Beersten’. ‘Exper. Oral Biology Group, Lab. ofCell Biology and Histology, Uniuersitu of Amsterdam, The Netherlands; -‘Laborutoire de Chimie Physiolog&e, Uniuersite de Louzlain and 10, UCL 75.39, Brussels, Belgium. Cysteine-proteinases (CP) and collagenase (matrix metalloproteinase 1, MMP 1) are known to participate in bone resorption. In the present study, their role was investigated at the level of the osteoclast resorption zone by evaluating the effects of selective proteinase inhibitors on the ultrastructure of that zone. Calvaria from 5 day old mice were cultured (up to 72 hr) in Medium 199 + 2.5% FCS with or without I’TH (1 U/ml), calcitonin (0.9 U/ml), the CP inhibitor E-64 (42 PM) and the MMP inhibitor Cl-l (40 PM). The explants were processed for microscopic (LM and EM) examination and morphometric analysis. In the presence of each of the two proteinase inhibitors a large area of bone matrix free of mineral was seen adjacent to the ruffled border of the osteoclasts. This area proved to be IO-times larger in inhibitortreated explants than controls (p
19. Demonstration of osteoclasts at different stages of the bone remodelling cycle: A histological and in situ biochemical study of adult human bone. R.A. Dodds, I.E. James, S. Walsh and M. Gowen. Bath Institute for Rheumatic Diseases, Trim Bridge, Bath BAZ IHD and Uniztersity of Bath. &i& studies of adult human bone are restricted by the very nature of the tissue: a hard mineralised matrix and relatively few cells per area of bone. We describe a human tissue in which there is sufficiently high bone turnover to allow the in study of human osteoclast activity at different stages of the bone remodelling cycle. Tartrate resistant acid phosphatase (TRAP) is used as a cytochemical marker of osteoclas&. Using an in biochemical method TRAP activity was measured in individual osteoclasts in cryostat sections by microdensitometry, and correlated with the location of the osteoclast within the tissue. Osteoclasts not associated with bone resorption showed two distinct populations: one with high (66.0 +/- 3.9 ; MIExlOO mean +/- SD. n=16) and one with lo’w (33.6 +/- 12.3. n=154) activity. Osteoclasts loosely associated with the bone surface but present in areas of active bone resorption demonstrated a broad spectrum of activity (49.3 +/13.1. n=128). Osteoclasts actively resorbing bone within Howship’s lacunae and often showing distinct localisation of enzyme activity towards the bone surface showed high activity (62.0 +/- 9.9. n=162). Thus we have demonstrated differential TRAP activity associated with osteoclast function at different stages of the resorptive cycle. This novel approach may therefore allow us to correlate expression of specific proteins within osteoclasts with the various stages of the osteoclast lite cycle.
20. Requirements for the differentiation of bone cells. S. Fitton Jackson and S. Bord. Strangezuays Research Laboratory, Cambridge CBl 4RN. Organ cultures of tibia1 rudiments taken from 14d chicken embryos are being used to investigate parameters involved in the differentiation of bone cells. Conditioned medium (CM) collected from feeder cultures grown in chemically- defined medium without serum over 9 days, during which numerous layers of osteogenic tissue develop to cover the underlying bone lamellae
1990
295
while osteoblasts and osteoid fill the lacunae, is being used to test the effects of CM on shafts at various stages of culture as judged by histology and measurements for alkaline phosphatase activity, SHthymidine and “5Ca uptake and the amount of calcium present. Gel electrophoresis of the CM taken at different time points shows that nearly 50% of the products from phase 1 (O-3d) are less than ZOkDa, as compared with 20-23% in CM from phases II and 111(3-6 and 69d resp:) where a dominant doublet in the 30kDa region is present. When shafts are grown for 6d in CM from either phases 11or III more osteoid is laid down and alkaline phosphatase activity is elevated by 25% (p=O.O5) over those grown in phase I CM. These results indicate that products present in CM from older cultures promote the rate of osteoblastic maturation.
21. The osteogenic ootential of neonatal porcine bone-marrow stromal cells Tn vivo. B.M. Thomusonl, N. Loverideel, M.C. Meikle*, 1. Bennett’ and 1. Triffit’. ’ ‘Bone Growth and Metabolism Unit, Rowett Research Institute, Aberdeen, lstrangeways Research Laboratory, Cambridge, ‘MRC Bone Research Laboratory, Nuffield Orthopaedic Centre, Oxford. As an alternative tissue source for skeletal research, diffusion chambers containing porcine bone-marrow fibroblasts or marrow cell suspensions (107cells/chamber) were implanted into the peritoneal cavities of nude mice for 75 days, fixed and prepared for histology. Transverse sections revealed the consistent formation of partially mineralised, cartilaginous bands (250-750pm), located next to the filters but separated from them by a thin fibrous layer. These bands gave typical metachromatic, perilacunar staining with toluidine blue and safronin-0. Mineralisation (van Kossa) was found in defined regions immediately adjacent to the membrane filter and, less frequently, in the body of the chamber, an area predominantly occupied by amorphous, acellular material. Alkaline phosphatase activity was localised both to cell layers lining between tissue types, and to isolated cells within the matrix but was not always present beside areas of mineralisation. No cells had acid phosphatase activity. oil red-0 stained occasional cells scattered throughout the chamber suggesting the existence of functional adipocytes. These results extend our observation that neonatal porcine bone marrow fibroblasts form mineralised, alkaline phosphatase positive nodules in the presence of dexamethasone and D-glycerophosphate and confirm that these cells are a valid model for investigating the mechanisms of skeletogenesis.
22. The osteogenic potential of bone marrow fibroblasts and adipocytes. J.H. Bennett, J.T. Triffitt and M.E. Owen. MRC Bone Research Laboratory, Nulfield Orthapaedrc Centre, Oxford OX3 7LD. Foetal calf serum (FCS) encourages the growth of fibroblastic colonies in marrow cell cultures. Conditions under which the adipocytic phenotype is clonally expressed in cultures of rabbit marrow cells are determined in the present study. Cloned cell populations from marrow adipocytic colonies are compared with those derived from marrow fibroblastic colonies, in terms of their potential for differentiation, by using the in culture diffusion chamber assay. 2 x 10: irradiated autologous marrow cells were used as feeder layers in medium containing FCS to obtain well spaced fibroblastic colonies suitable for ring cloning. Single adipocytic colonies were obtained by first removing non-adherent cells, washing the cultures twice and culturing the remaining adherent cells with autologous rabbit plasma as supplement. Adipocytic colonies (21) and fibroblastic colonies (28) were isolated and expanded. Eight colonies from each group provided enough cells (2 x 10s to 2 x 100) for separate implantation and culture within diffusion chambers m. Three of the eight colonies of each group formed a mixture of bone, cartilage and fibrous tissues in the
Abstracts from the Bone and Tooth Society Meeting,
296
diffusion chambers, with the rest containing fibrous tissue only or no detectable tissue. These results support the hypothesis that adipocytic, fbroblastic and osteogenic cells present in bone marrow, have a common precursor.
23. A sequence of adaptive change following mechanical loading in bone organ cultures. G. Zaman, S.L. Minter, M.J. Pead, M.J. Morgan and L.E. Lanyon. Department of Veterinary Basic Sciences, The Royal Veterinay College, University of London. Cyclic mechanical loads, producing physiological strains, were applied to 17 day embryonic chick tibiae in organ culture. The effect of loading on RNA synthesis, glucose 6-phosphate dehvdroeenase (G6PD) activity and production of type I collagen mI&A w”as investigated. Imkediateiy following Zdminutes 07 loading, there was a load magnitude-related increase in G6PD activity in periosteal osteoblasts and osteocytes. This effect was blocked bv indomethacin (IO-fiM). 24 hours following a similar period of loading there was a load magnitude-relate8 increase in the incorporation of ?H-uridine into extracted RNA. In situ hybridization studies demonstrated that 18 hours after loading type I collagen mRNA expression was increased in alkaline phosphatase positive cells. The effect was not detectable at 4 hours. The load-related increase in type 1 Collagen mRNA indicates that this model may exhibit all the steps between loading and its “osteogenic” response. Load-related increases in G6PD activity and RNA synthesis, which can be blocked by indomethacin, have previously been demonstrated in vivo and in vitrol’,2,91 and may form part of this pathway. Pead M.J. et al (1988) C&if. Mm
Res. 4: 783.788,
lissue
ht.
43: 92-96, Skerry
El Haj et al (1990) J. Bone & Mm
Both chicken and rat CGRP (c and r-CGRI’) promote plasma clearance of simultaneously administered 4iCa in chicks (1) and cCGRP promotes &Ta upta&e into bone in (2). We now report uoon the effects of r-CGRP in the chick. In 22hr fasted chicks (<00+5g), r-CGRP (1.71nMol/lOOg body wt, iv.) significantly increased bone ‘SCa uptake, peak responses 10 min after injection, were sternum (129%) and femur (118%) of control values. In a dose-resoonse curve the most effective dose at IOmin was l.l4nMdl/lUOg, while a higher dose (4,65nMol/lOOg) gave partial reversal. Bv contrast, in continuouslv fed chicks, r-CGRP (l.l4nMol?lOOg) significantly reduced label deposition into sternum (85.7%) and femur (91 .l%) of controls. Surprisingly, in 22hr fasted chicks, salmon calcitonin (4.56nMol/lOOg body wt) significantly reduced 4jCa uptake, the greatest responses, as a percentage of control values, were calvarium (82.6%), femur (64.5%) and sternum (62%). We conclude that r-CGRP, like c-CGRP, promotes h’luptake into chick bone in the heterologous peptide appears to be more potent. CGRP is also hypercalcaemic in chicks, suggesting a complex action consisting of at least two opposing effects. Regulatory
Peptides
(In press),
1990
ntzd *ICI Phnrmncelrticnls, Meresidr, Alderle!y Pnrk, Mncclesfirld. Cheshire, SK10 4TG. In man, retinoids induce adverse long bone effects including thinning, remodelling and premature epiphyseal closure. We examin:d long bonesfrom*TRA-treated rat; to quantify aspects of these effects. Twentv-five male Wistar rats were divided into 5 groups. On day (d) b, 5 rats were PM’d, the remainder being dosed orally with TRA daily at 0, lo,20or 30 mg/kg until PM (d37). The femur, tibia, fibula, humerous, radius and ulna were measured using callipers and weighed. Diaphyses were sectioned transversely in 3 positions for medullary cavity diameter and cortical bone thickness measurement. TRA did not affect body weight or bone length but induced a dose-related weight reduction in all bones. TRA also induced a dose-related reduction in diameter at mid-shaft but the effect was less marked towards the epiphyses. Although cortical bone thickness was comparable in all parts at d37, TRA induced dose-related reductions in medullary cavity diameters of all bones. The degree of this latter effect varied between bones and along their length. In all rats, diaphysis diameter generally increased from d0 to d37, but with higher levels of TRA the extent to this increase was reduced. These results show that TRA reduced periosteal depositionand increased endosteal deposition in a dose-related manner. However, there were no adverse effects on bone length increases.
26. Dietary acid-base balance and bone metabolism. H. Abu Damir, W. Buchan, J. Milne, N. Loveridge and D. Scott Rowett Research Institute, Greenburn Road, Aberdeen AB2 9SB. Scotland.
et al (1989) J. Bone &
Res. (In press).
24. A comaarison of chicken and rat calcitonin gene-related peptide (eGRP1 upon bone Wa uptake in chic&. A.K. Ancill. Z.A. Bascal. G. Whitaker and C.G. Dacke Division of bharmacology; School of Pharmacy, Portsmouth Polytechnic, Portsmouth, Hants, PO1 2DT.
A.K. Ancill et
September
Z.A. Bascall
d
(1990) Bone
(In press).
In earlier studies, growing lambs retained less calcium on diets containing ammonium chloride (NH&I) than on those containing sodium bicarbonate (NaHCO,). This study investigates the possible mechanism for this difference. Lambs (25kg) were fed diets containing either NH,Cl (log/kg; n=6) or NaHCO, (20g/kg; n=6) for 9 weeks. Radiochemical and chemical calcium balance measurements over a final 8 day period showed similar dietary calcium absorption (3.59 vs 3.20g/day) but a reduction in calcium retention (1.45 vs 2.34g/day; ~~0.05) and increased urinary calcium loss (0.97 vs 0,05g/day; p
27. Correction of vitamin D deficiencv in elderly long-stay . . patients by sunlight exposure. ’ A.R. Webb’, G.A. CampbelP, MS. Steven’ and D.J. Hosking 4. lDepartment Meteorology, Reading University, Reading RG6 2AU, *Cambridge Health Authority, Department of Geriatirc Medicine, Addenbrookes Hospital, Hills Road, Cumbridge CB2 ZQQ, IDepartment of Geography, University Park, Nottingham NG7 2RD and 4Department Medicineand Health Care of the Elderly, University Hospital, Nottingham.
of
of
25. Long bone thinning and remodelling in the rat induced by all-mretinoic acid (TRA). A.T. Keene, G.B. Willars, M.J. Tucker* and J.A. Turton. Toxicology Unif, Department of Pharmacology, The School of Pharmacy, (Utriversity ofLondon), 29-39 Brunswick Square, London WCIN 1AX
It is generally accepted that ultraviolet-B (UVB) radiation is important in maintaining an adequate vitamin D status, Darticularlv if dietan, intake is low. However, the rate of production of vitamin D in vivo and the amount of sunlight required for health have yet to be quantified. In order to study the