Susceptibility to Osteoporotic Fracture is Determined by Allelic Variation at the Sp1 Site, Rather than Other Polymorphic Sites at the COL1A1 Locus

Previous studies have identified an association between osteoporotic fracture and a polymorphism affecting a Sp1 binding site in the first intron of the collagen type I alpha 1 gene (COL1A1). It is currently unclear, however, whether this association is direct or the result of linkage disequilibrium with other polymorphisms situated nearby. In this study we analyzed the relationship between four well-characterized single-nucleotide polymorphisms at the COL1A1 locus and osteoporotic fracture in 93 patients with vertebral fracture and 88 age-matched controls randomly selected from the community. We studied a Msp I polymorphism 26 kb upstream of the COLIA1 gene, the Sp1 binding site polymorphism in intron 1, a Rsa I polymorphism in intron 5 and a Mnl I polymorphism in exon 52. The Sp1 and Rsa I polymorphisms were in strong linkage disequilibrium (χ²=77.87, p<0.001) and weaker linkage disequilibrium was detected between the Sp1 and Mnl I polymorphisms (χ²=5.54, p<0.025). There was a significant association between COL1A1 haplotypes that included the Sp1 and Rsa I polymorphisms and fracture (p<0.05–0.001), but no association with haplotypes that included only the Msp I and Mnl I polymorphisms. This association with fracture was strongest when haplotypes were grouped by Sp1 alleles (χ²=11.15, d.f. = 1; p= 0.001). Furthermore, logistic regression analysis showed that of all the polymorphisms tested, only the Sp1 binding site polymorphism acted as an independent predictor of fracture: odds ratio [95% CI] = 2.26 [1.09–4.69]. These data suggest that it is the Sp1 polymorphism rather than other polymorphisms at the COL1A1 locus which act as a marker for osteoporotic fractures. Received: 1 July 1999 / Accepted: 28 September 1999     

Ultraviolet irradiation of blood prevents transfusion-induced sensitization and marrow graft rejection in dogs

In a canine model using DLA-identical littermate pairs, we have shown that a regimen of three transfusions of donor blood given 24, 17, and 10 days before transplant uniformly leads to marrow graft rejection, presumably due to sensitization to minor (non-DLA) histocompatibility antigens. Untransfused dogs uniformly achieve sustained engraftment. In the present study, we investigated whether the exposure of blood to ultraviolet (UV) light (220-300 nm) prior to transfusion prevented sensitization of the recipient and allowed for successful marrow engraftment. Ten dogs were each given three pretransplant transfusions from the marrow donor. Each transfusion consisted of 50 mL of whole blood exposed in vitro to UV light for a total of 1.35 J/cm2. All ten dogs achieved engraftment. In contrast, all four dogs that had received sham-exposed transfusions rejected their grafts. In vitro studies revealed that although cell viability was not affected, leukocytes contained in UV-exposed blood were unable to function as stimulator cells in mixed leukocyte cultures or as accessory cells in mitogen- stimulated cultures. These data are consistent with the hypothesis that accessory cells are involved in transfusion-induced sensitization. We conclude that in vitro exposure of blood to UV light before transfusion prevents sensitization and allows for subsequent marrow engraftment.     

Fluid loading with whole blood or Ringer's lactate solution during CPR in dogs

The influence of fluid loading during CPR on oxygen uptake and blood flow was investigated in 18 dogs (12-26 kg). Blood flows were measured with radioactive microspheres at 5 (control CPR), 13 and 20 min after the initiation of ventricular fibrillation and CPR. After 10 min, 9 dogs received a rapid infusion of whole blood (11 ml/kg, i.v.) and 9 dogs received Ringer's solution (11 ml/kg, i.v.). Oxygen uptake was not significantly altered by fluid loading with either whole blood or Ringer's solution. Fluid loading increased cardiac output 34% over the 5 min control value. However, left ventricular perfusion decreased to 74% and brain flow decreased to 65% of control. At 20 min, cardiac output and brain flow returned to near control values, while left ventricular flow remained low. Changes in organ perfusion can be explained in part by the concurrent changes in blood pressures. Central venous diastolic pressure increased significantly (from 9 to 14 mmHg) after fluid load. However, central arterial diastolic pressure did not rise proportionately (from 32 to 34 mmHg). Hence, the central A-V diastolic pressure difference decreased. Although fluid loading during CPR improved cardiac output, flow to the heart and brain decreased. Further, there was no increase in oxygen consumption, indicating that fluid loading did not improve metabolic status.     

Fine structure of the spinothalamic projections to the central lateral nucleus of the rat thalamus

The fine structure of labelled spinothalamic terminals in the central lateral nucleus has been studied in the rat following injection of wheat germ agglutinin-horseradish peroxidase into the spinal cord. Myelinated axons gave rise to the labelled terminals, which were large profiles which contained round vesicles, numerous mitochondria, and formed asymmetrical contacts with large dendrites or dendritic protrusions. These profiles are similar to those described in other somatosensory thalamic nuclei, and in many other nuclei of the thalamus.     

Clinical, biochemical, and radiographic effects of aminohydroxypropylidene bisphosphonate treatment in rheumatoid arthritis.

A placebo controlled, double blind study of aminohydroxypropylidene bisphosphonate (APD), given by monthly intravenous infusion, was conducted in 40 patients with rheumatoid arthritis. Biochemical markers of increased bone resorption, such as fasting urinary calcium/creatinine ratio and hydroxyproline/creatinine ratio, were suppressed significantly in the APD group to approximately 50% and 60% of the pretreatment level respectively, and serum calcium fell transiently after the first APD infusion. There was no significant effect on disease activity in either the APD or placebo groups as judged by clinical (grip strength, morning stiffness, visual analogue score) or laboratory (haemoglobin, platelet count, erythrocyte sedimentation rate, C reactive protein) criteria. An exception was the articular index which improved to a similar degree in both groups, falling from (mean (SEM] 13.8 (1.8) to 7.2 (2.2) in the APD group and from 13.7 (1.9) to 6.8 (1.5) in the placebo group. Radiological progression occurred to a similar degree in both groups as assessed by the Sharp index (mean (SEM) 86 (13.1) v 95 (12.9)-APD group; 103 (15.1) v 110 (15.8)-placebo group), but there was no significant change in the Larsen index in either group (mean (SEM) 53 (4.2) v 57 (3.8)-APD; 62 (5.8) v 63 (5.6)-placebo). The lack of effect on radiological progression in the APD group indicates that focal erosive disease may either have progressed as the result of a non-osteoclast related mechanism, or that the intensity of bone resorption was too great to be inhibited by the doses of APD used. The biochemical response to APD presumably reflected inhibition of bone resorption at other sites, suggesting that further studies of the effects of bisphosphates on periarticular and systemic osteoporosis in rheumatoid arthritis may be of the interest.     

Inhibition of bone resorption in vitro and prevention of ovariectomy-induced bone loss in vivo by flurbiprofen nitroxybutylester (HCT1026)

OBJECTIVE: Inhibitors of prostaglandin production, such as nonsteroidal antiinflammatory drugs (NSAIDs), and pharmacologic nitric oxide (NO) donors, such as organic nitrates, have been suggested to protect against bone loss in both humans and experimental animals. Recently, a new class of nitrosylated NSAID (known as NO-NSAIDs) has been developed, which combines the properties of a NO donor with those of a cyclooxygenase (COX) inhibitor. This study investigated the effects of one of these compounds, flurbiprofen nitroxybutylester (HCT1026), on bone metabolism in vitro and in vivo. METHODS: The effects of HCT1026 on osteoclast formation and resorption were determined in vitro using cocultures of primary mouse osteoblasts and osteoclasts. The effect of HCT1026 in vivo was assessed using a mouse model of ovariectomy-induced bone loss. RESULTS: HCT1026 was significantly more efficacious than the parent compound, flurbiprofen, at inhibiting osteoclast formation and bone resorption in vitro, and these effects could not be reproduced by combinations of flurbiprofen with a variety of NO donors. Studies in vivo showed that HCT1026 protected against ovariectomy-induced bone loss by inhibiting osteoclastic bone resorption, whereas flurbiprofen at similar concentrations was ineffective. CONCLUSION: These data indicate that HCT1026 is a potent inhibitor of bone resorption in vitro and protects against ovariectomy-induced bone loss in vivo by a novel mechanism that appears to be distinct from its NO donor properties and from its inhibitory effects on COX activity. We conclude that HCT1026 may be of clinical value in the prevention and treatment of inflammatory diseases such as rheumatoid arthritis, which are characterized by joint inflammation as well as periarticular and systemic bone loss.     

A UK Consensus Group on management of glucocorticoid-induced osteoporosis: an update

Abstract. Eastell R, Reid DM, Compston J, Cooper C, Fogelman I, Francis RM, Hosking DJ, Purdie DW, Ralston SH, Reeve J, Russell RGG, Stevenson JC, Torgerson DJ (University of Sheffield Medical School, Sheffield; University of Aberdeen, Aberdeen; University of Cambridge School of Clinical Medicine, Addenbrooke's Hospital, Cambridge; Southampton General Hospital, Southampton; Guy's Hospital, London; Freeman Hospital, Newcastle upon Tyne; Nottingham City Hospital, Nottingham; Hull Royal Infirmary, Hull; Wynn Institute for Metabolic Research, London; and the University of York, York, UK). A UK Consensus Group on management of glucocorticoid-induced osteoporosis: an update (Review). J Intern Med 1998; 244: 271–292.
In the UK, over 250 000 patients take continuous oral glucocorticoids (GCs), yet no more than 14% receive any therapy to prevent bone loss, a major complication of GC treatment. Bone loss is rapid, particularly in the first year, and fracture risk may double. This review, based wherever possible on clinical evidence, aims to provide easy-to-use guidance with wide applicability. A treatment algorithm is presented for adults receiving GC doses of 7.5 mg day⁻¹ or more for 6 months or more. General measures, e.g. alternative GCs and routes of administration, and therapeutic interventions, e.g. cyclical etidronate and hormone replacement, are recommended.