Calcium oxalate crystal adherence to hyaluronan-, osteopontin-, and CD44-expressing injured/regenerating tubular epithelial cells in rat kidneys

Retention of crystals in the kidney is an essential early step in renal stone formation. Studies with renal tubular cells in culture indicate that hyaluronan (HA) and osteopontin (OPN) and their mutual cell surface receptor CD44 play an important role in calcium oxalate (CaOx) crystal binding during wound healing. This concept was investigated in vivo by treating rats for 1, 4, and 8 d with ethylene glycol (0.5 and 0.75%) in their drinking water to induce renal tubular cell damage and CaOx crystalluria. Tubular injury was morphologically scored on periodic acid-Schiff-stained renal tissue sections and tissue repair assessed by immunohistochemical staining for proliferating cell nuclear antigen. CaOx crystals were visualized in periodic acid-Schiff-stained sections by polarized light microscopy, and renal calcium deposits were quantified with von Kossa staining. HA was visualized with HA-binding protein and OPN and CD44 immunohistochemically with specific antibodies and quantified with an image analyzer system. Already after 1 d of treatment, both concentrations of ethylene glycol induced hyperoxaluria and CaOx crystalluria. At this point, there was neither tubular injury nor crystal retention in the kidney, and expression of HA, OPN, and CD44 was comparable to untreated controls. After 4 and 8 d of ethylene glycol, however, intratubular crystals were found adhered to injured/regenerating (proliferating cell nuclear antigen positive) tubular epithelial cells, expressing HA, OPN, and CD44 at their luminal membrane. In conclusion, the expression of HA, OPN, and CD44 by injured/regenerating tubular cells seems to play a role in retention of crystals in the rat kidney

Cholesterol feeding accentuates the cyclosporine-induced elevation of renal plasminogen activator inhibitor type 1

Cholesterol feeding accentuates the cyclosporine-induced elevation of renal plasminogen activator inhibitor type 1. Long-term cyclosporine (CsA) therapy is accompanied by the occurrence of hypercholesterolemia and renal interstitial fibrosis. The present study investigates the effect of dietary cholesterol on CsA-induced lipid disturbances in the rat and on CsA nephrotoxicity. Since plasminogen activator inhibitor type 1 (PAI-1) is a major inhibitor of matrix degradation and elevated plasma PAI-1 levels are reported to be associated with increased low-density lipoprotein (LDL) cholesterol, PAI-1 was examined in the kidneys of rats fed a sodium-deficient diet, with or without cholesterol. After nine weeks, both diet groups were subdivided into a CsA-treated group and a vehicle-treated group. Although cholesterol feeding significantly aggravated CsA-induced renal function impairment, CsA-induced histological lesions were comparable in both diet groups. Cholesterol feeding significantly decreased high-density lipoprotein (HDL) cholesterol irrespective of the treatment, while CsA treatment significantly elevated serum triglycerides irrespective of the diet. Cholesterol feeding alone did not increase the number of infiltrating cells in the renal interstitium. In contrast, in both diet groups CsA treatment caused a significant influx of macrophages, while combined treatment with CsA and cholesterol additionally elevated the number of T-helper cells in the cortex. In all rats, PAI-1 immunostain-ing was found mainly in intracellular vesicles (lysosomes) in proximal tubules, which stained most intensely in fibrotic areas of kidneys from CsA-treated rats. Cholesterol feeding enhanced the CsA-induced elevation of renal PAI-1 immunostaining to a significant level. These results show that, although serum creatinine, PAI-1 staining and cell influx were significantly increased in the cholesterol-fed CsA-treated group compared to the other groups, renal CsA-induced histological lesions were not influenced by cholesterol feeding after short-term (3 weeks) CsA administration. To what extent the more pronounced proximal tubular PAI-1 (inhibitor of matrix degradation) immunostaining in fibrotic areas in the cortex of cholesterol-fed CsA-treated rats contributes to the progression of CsA-induced renal fibrosis remains to be determined

Radiolocalisation and imaging of stably HPLAP-transfected MO4 tumours with monoclonal antibodies and fragments.

Immunotargeting of PLAP-expressing tumours was studied for two radioiodinated, highly specific anti-PLAP monoclonal antibodies, 7E8 and 17E3, differing 10-fold in affinity, as well as for 7E8 F(ab')2 fragments. An anti-CEA monoclonal antibody or anti-CD3 F(ab')2 fragments were used as controls. Specific and non-specific targeting was examined in nude mice simultaneously grafted with PLAP-positive tumours derived from MO4 1-4 cells, and CEA-positive tumours, derived from 5583-S cells. Results indicated that (1) MO4 1-4 tumours, with a stable expression of PLAP on the plasma membrane, represent a useful new in vivo model for immunodirected tumour targeting; (2) differences in antibody affinity for PLAP in vitro are not reflected in antibody avidity for tumour cells in vivo; and (3) excellent selective and specific localisation of the PLAP-positive tumours is achieved when 7E8 F(ab')2 fragments are used. The high tumour/blood ratios (10.7 +/- 3.9 at 46 h after injection) were due to a much faster blood clearance of 7E8 F(ab')2 fragments. At this time point, the mean tumour/non-tumour tissue ratio was as high as 34.5, and the mean specific localisation index was 29.0. As expected, the F(ab')2 fragments provided high tumour imaging efficiency on gamma camera recording. These data imply important potentials of the PLAP/anti-PLAP system for immunolocalisation and therapy in patients, but also emphasise that in vitro criteria alone are not reflected in in vivo tumour localisation capacities of antibodies

Oxidative modification of low-density lipoproteins and the outcome of renal allografts at 11/2 years

Oxidative modification of low-density lipoproteins and the outcome of renal allografts at 11/2 years.BackgroundPrevious studies reported a significant association between hyperlipidemia of the recipient and chronic allograft nephropathy (CAN). However, the nature and the pathogenic mechanism of circulating lipid abnormalities in CAN remain unclear.MethodsIn a prospective study of 50 consecutive adult recipients of a cadaveric renal allograft, we investigated the impact of lipid abnormalities on the outcome of the graft at 11/2 years. Besides morphometric analysis of implantation and protocol biopsies, clinical and biochemical variables were studied at three-month intervals. Plasma concentrations of oxidized low-density lipoprotein (OxLDL) were determined by means of enzyme-linked immunosorbent assay. Immunohistochemical staining for OxLDL and macrophages was performed on paired renal biopsies. Study end points were the fractional interstitial volume and the 24-hour creatinine clearance at 11/2 years.ResultsHigh-density lipoprotein (HDL) cholesterol of the recipient ≤47 mg/dL was a risk factor for the functional (RR = 1.56; 95% CI, 0.978 to 2.497) and the morphological (RR = 2.75; 95% CI, 1.075 to 7.037) outcome of the graft, mainly in patients without acute rejection (RR = 2.03; 95% CI, 1.13 to 3.65, and RR = 4.67; 95% CI, 1.172 to 18.582, respectively). Interstitial accumulation of OxLDL was inversely associated with HDL cholesterol (R = -0.476, P = 0.019), and was associated with a higher density of tubulointerstitial macrophages (R = 0.656, P = 0.001) and a higher fractional interstitial volume at 11/2 years (P = 0.049).ConclusionDecreased HDL cholesterol levels of the recipient adversely affect the outcome of renal allografts through the accumulation of OxLDL in the renal interstitium of the graft. Interstitial accumulation of OxLDL was associated with the presence of macrophages and the development of interstitial fibrosis

Prevention of Fractures in Older People with Calcium and Vitamin D

The greatest cause of fracture in older people is osteoporosis which contributes to increased morbidity and mortality in older people. A number of meta-analyses have been performed assessing the effectiveness of calcium supplementation alone, vitamin D supplementation alone and the combined therapy on bone loss and fracture reduction in older people. The results of these meta-analyses indicate that vitamin D supplementation alone is unlikely to reduce fracture risk, calcium supplementation alone has a modest effect in reducing total fracture risk, but compliance with calcium supplements is poor in the long term. The combination of calcium supplementation with vitamin D supplementation, particularly in those at risk of marginal and low vitamin D status reduces total fractures, including hip fractures. Therefore older people would be recommended to consume adequate dietary calcium (>1100 mg/day) together with maintaining adequate vitamin D status (>60 nmol/L 25(OH)D) to reduce risk of fracture. It is a challenge to consume sufficient dietary calcium from dietary sources, but the increasing range of calcium fortified foods could assist in increasing the dietary calcium intake of older people. In addition to the usual dairy based food sources, vitamin D supplements are likely to be required for older people with reduced mobility and access to sunlight

Older Aboriginal Australians' Health Concerns and Preferences for Healthy Ageing Programs.

While there is strong evidence of the need for healthy ageing programs for older Aboriginal Australians, few are available. It is important to understand older Aboriginal Australians' perspectives on healthy ageing in order to co-design culturally-appropriate programs, including views on technology use in this context. Semi-structured interviews were conducted with 34 Aboriginal Australians aged 50 years and older from regional and urban communities to explore participants' health concerns, preferences for healthy ageing programs, and receptiveness to technology. Qualitative data were analyzed using a grounded theory approach. This study found that older Aboriginal Australians are concerned about chronic health conditions, social and emotional well-being, and difficulties accessing health services. A range of barriers and enablers to participation in current health programs were identified. From the perspective of older Aboriginal people, a successful healthy ageing program model includes physical and cognitive activities, social interaction, and health education. The program model also provides culturally safe care and transport for access as well as family, community, cultural identity, and empowerment regarding ageing well as central tenets. Technology could also be a viable approach for program delivery. These findings can be applied in the implementation and evaluation of culturally-appropriate, healthy ageing programs with older Aboriginal people

Complexity of global semianalytic sets in a real analytic manifold of dimension 2

Let X subset of R-n be a real analytic manifold of dimension 2. We study the stability index of X, s(X), that is the smallest integer s such that any basic open subset of X can be written using s global analytic functions. We show that s(X) = 2 as it happens in the semialgebraic case. Also, we prove that the Hormander-Lojasiewicz inequality and the Finiteness Theorem hold true in this context. Finally, we compute the stability index for basic closed subsets, S, and the invariants t and (t) over bar for the number of unions of open (resp. closed) basic sets required to describe any open (resp. closed) global semianalytic set

Reliability of retinal vessel calibre measurements using a retinal oximeter

Background: Summarised retinal vessel diameters are linked to systemic vascular pathology. Monochromatic images provide best contrast to measure vessel calibres. However, when obtaining images with a dual wavelength oximeter the red-free image can be extracted as the green channel information only which in turn will reduce the number of photographs taken at a given time. This will reduce patient exposure to the camera flash and could provide sufficient quality images to reliably measure vessel calibres. Methods: We obtained retinal images of one eye of 45 healthy participants. Central retinal arteriolar and central retinal venular equivalents (CRAE and CRVE, respectively) were measured using semi-automated software from two monochromatic images: one taken with a red-free filter and one extracted from the green channel of a dual wavelength oximetry image. Results: Participants were aged between 21 and 62 years, all were normotensive (SBP: 115 (12) mmHg; DBP: 72 (10) mmHg) and had normal intra-ocular pressures (12 (3) mmHg). Bland-Altman analysis revealed good agreement of CRAE and CRVE as obtained from both images (mean bias CRAE = 0.88; CRVE = 2.82). Conclusions: Summarised retinal vessel calibre measurements obtained from oximetry images are in good agreement to those obtained using red-free photographs