Diet, weight, cytokines and bone health in postmenopausal women.

OBJECTIVES: To investigate diet and nutrition-related factors associated with bone loss in a group of postmenopausal (PM) women. Nutritional intake, inflammatory markers and body composition (weight, body mass index, fat/lean mass) were analysed for associations with bone mineral density (BMD). DESIGN: A cross sectional study examining correlations between BMD (Duel-energy X ray absorptiometry; (DXA) and dietary intake (3-day diaries), body composition and plasma bone and inflammatory markers: C-terminal telopeptide of type I collagen (CTX) and procollagen type I N propeptide (P1NP), C- reactive protein (CRP), interleukin 6 and 10 (IL-6, IL-10), tumour necrosis factor (TNF) and osteoprotegerin (OPG). SETTING: Community dwelling women from the Auckland, Hawke's Bay and Manawatu regions in New Zealand. PARTICIPANTS: 142 healthy, PM women aged 50-70 years. RESULTS: OPG (per kilogram fat mass) was increased in women with osteoporosis (p<0.001) compared to groups classified with normal BMD and osteopenia. Protein, vitamin B12, zinc, potassium and dairy intake were all positively correlated with higher BMD while dairy and potassium intakes also inversely correlated with CTX. Body composition (weight, BMI and fat/lean mass) had strong positive associations with BMD. Multiple regression analysis showed body weight, potassium and dairy intake were predictors of increased BMD in PM women and explained 39% (r2=0.39, p< 0.003) of variance. CONCLUSION: BMD was negatively correlated with OPG and positively with weight, dairy and potassium intake. This study highlights the importance of maintaining adequate body weight and emphasising dairy and potassium predominantly sourced from fruit/vegetables to reduce bone loss at midlife.

Immunohistochemical determination of complement activation in joint tissues of patients with rheumatoid arthritis and osteoarthritis using neoantigen-specific monoclonal antibodies.

Murine monoclonal antibodies specific for neoepitopes expressed by C9 incorporated into membrane attack complexes and by membrane-bound C3b and iC3b have been prepared and characterised. These reagents were used to determine the extent and locus of complement activation in synovial-tissues obtained from patients with rheumatoid arthritis and osteoarthritis. In the four rheumatoid arthritis patients there was extensive deposition of C3 activation products and C5b-9 complexes onto the synovial membrane and the pattern of deposition of both neoantigens in serial tissue sections was very similar. There was less extensive staining for C3 and, particularly, C9 neoepitopes on the apical surface of vessel endothelia. In two of four osteoarthritic patients a similar pattern of C3 and C9 neoepitope deposition was found; in the remaining patients no C5b-9 could be located. Synovial vessel walls, but not synovial cells, from both groups of patients stained extensively for the complement regulatory protein CD59. In synovial membranes from patients with osteoarthritis, C9 appeared to be present predominantly in SC5b-9 complexes whereas in rheumatoid arthritis patients no evidence of S-protein incorporation into membrane attack complexes could be demonstrated, suggesting that in rheumatoid arthritis there is damage to the synovial membrane as a result of complement activation and C5b-9 deposition.

Identification of an encephalitogenic determinant of myelin proteolipid protein for the rabbit.

A late onset, demyelinating form of experimental allergic encephalomyelitis (EAE) was induced in New Zealand White rabbits following immunisation with a synthetic peptide representing the amino acid sequence 91-110 of bovine myelin proteolipid protein (PLP). Histologically, disease was associated with varying degrees of central nervous system (CNS) inflammation, which in six of seven animals was accompanied by axonal degeneration and secondary demyelination. Primary demyelination with axonal sparing was generally absent in this model of EAE. Immunohistochemical and immunoelectron microscopic analysis of CNS tissue indicate that B cell epitopes within this encephalitogenic PLP sequence are not exposed at the surface of the myelin sheath, but are sequestered within compact multilamellar myelin. Furthermore, no correlation was observed between the anti-PLP antibody titer induced by the peptide and either the clinical severity or histopathology of the disease. These observations suggest that the B cell response to epitopes within the PLP sequence 91-110 does not play a primary role in the immunopathogenesis of PLP-induced EAE.

The immune response to myelin proteolipid protein in the Lewis rat: identification of the immunodominant B cell epitope.

The polyclonal antibody response of the Lewis rat to bovine myelin proteolipid protein (PLP) has been investigated following immunisation with either the purified protein or bovine central nervous system myelin. In both situations, the carboxyl-terminal sequence of PLP was identified as the immunodominant domain of this protein and epitope mapping demonstrated that the carboxyl-terminal amino acid, phenylalanine276, was a critical requirement for antibody recognition of this epitope. This single epitope accounted for approximately 78% and 56% of the antibody response to PLP in rats immunised with PLP or bovine myelin, respectively. Polyclonal rat antibodies specific for this carboxyl terminal epitope of PLP were also obtained following immunisation with a synthetic 20 amino acid oligopeptide analogue of the carboxyl-terminal sequence of PLP. Western blotting demonstrated this antibody response was specific for the PLP and DM-20 components of mammalian central nervous system myelin. In contrast, no major PLP epitopes were detected within the PLP amino acid sequences 35-58 and 91-150, the other major hydrophilic domains of this protein.

DQA2 U allele: a genetic marker for relapse of Graves' disease.

The association of HLA-DR3 with Graves' disease in Caucasoids is well established but its significance is unclear and its clinical value as a predictive parameter for relapse after a course of antithyroid drug therapy is controversial. We have further investigated the predictive value at the genomic level in 51 patients with Graves' disease who were treated with a 6-month course of carbimazole and followed up for 2 years. Using DNA-restriction fragment length polymorphism (DNA-RFLP) allogenotyping, (i) complete concordance of HLA-DR assignment was observed between serological and DNA-RFLP analysis of all but one of 51 patients with Graves' disease; (ii) the DR beta 17(1)-DQ alpha 2-DQ beta 2a (a DNA-RFLP allogenotype of the classical Northern European haplotype of HLA-B8 DR3) was significantly (corrected P = Pcorr less than 0.02) associated with Graves' disease particularly in patients who relapsed (Pcorr less than 0.005); (iii) HLA-DR3 was highly associated with DQA2 U allele (chi 2 = 18.53, d.f.2, P less than 0.0005); (iv) a strong correlation between the DQA2 U allele and the outcome of the disease was observed. Relapse occurred in 91% (10/11) of the patients who were homozygous for the DQA2 U allele whilst only 65% (15/23) and 41% (7/17) of patients who were hetero or homo-zygous for the DQA2 L allele (DQA2 U/L and DQA2 L/L) relapsed within the same period of follow-up (chi 2 = 7.18, d.f.2, P less than 0.05). Though the relapse rate in patients with the DQA2 U/U genotype was not significantly higher than the relapse rate in patients with the DQA2 U/L genotype, it was significantly higher than the relapse rate in patients with DQA2 L/L genotype (P less than 0.0001) with a relative risk of 14.3.

The production and characterization of monoclonal antibodies to the human thyroid microsome.

By suitable immunization of mice and fusion of their spleen cells with a non-secretor mouse myeloma line, monoclonal antibodies have been produced which react with the human thyroid microsomal (M) antigen. These monoclonal antibodies showed no reactivity by enzyme-linked immunoassay with liver microsomes or thyroglobulin and their specificity was confirmed by immunolocalization studies, in which they showed the staining characteristics of human M antibodies. All four monoclonal antibodies tested were immunoglobulin M; three were cytotoxic to thyroid cell monolayers. The lack of cytotoxicity with the fourth monoclonal supports the concept that certain epitopes of the M antigen may be partially or completely absent at the thyroid cell surface. These monoclonal antibodies should permit further characterization of the thyroid M antigen in view of their absence of cross-reactivity with thyroglobulin.