Advanced glycation end product (AGE) accumulation on Bruch's membrane: links to age-related RPE dysfunction.

PURPOSE: Advanced glycation end products (AGEs) accumulate during aging and have been observed in postmortem eyes within the retinal pigment epithelium (RPE), Bruch's membrane, and subcellular deposits (drusen). AGEs have been associated with age-related dysfunction of the RPE-in particular with development and progression to age-related macular degeneration (AMD). In the present study the impact of AGEs at the RPE-Bruch's membrane interface was evaluated, to establish how these modifications may contribute to age-related disease. METHODS: AGEs on Bruch's membrane were evaluated using immunohistochemistry. A clinically relevant in vitro model of substrate AGE accumulation was established to mimic Bruch's membrane ageing. Responses of ARPE-19 growing on AGE-modified basement membrane (AGE-BM) for 1 month were investigated by using a microarray approach and validated by quantitative (q)RT-PCR. In addition to identified AGE-related mRNA alterations, lysosomal enzyme activity and lipofuscin accumulation were also studied in ARPE-19 grown on AGE-BM. RESULTS: Autofluorescent and glycolaldehyde-derived AGEs were observed in clinical specimens on Bruch's membrane and choroidal extracellular matrix. In vitro analysis identified a range of dysregulated mRNAs in ARPE-19 exposed to AGE-BM. Altered ARPE-19 degradative enzyme mRNA expression was observed on exposure to AGE-BM. AGE-BM caused a significant reduction in cathepsin-D activity in ARPE-19 (P

Archaeological and Palaeoecological investigations of a Middle Bronze Age settlement at Ballyarnet Lake, Co. Derry

Excavations at Ballyarnet Lake, Co Derry, have identified a Middle Bronze Age settlement site at the margins of the lake. The site is characterised by a palisaded enclosure surrounding a structure containing a hearth. Finds include a large quantity of Cordoned Urn ware, lithics and a faience bead. Palaeoenvironmental studies, including pollen, plant macrofossil and beetle analyses, provide insights into the environmental background of the settlement. The site is considered in terms of the broader context of Middle Bronze Age settlement.

Tuberculosis among Iron Age individuals from Tyva, South Siberia: palaeopathological and biomolecular findings

The study focuses on the evidence for tuberculosis apparent in an Iron Age population recovered from the cemetery of Aymyrlyg, Tyva (Tuva), South Siberia. A recent wholly molecular study of five of the cases confirmed the presence of Mycobacterium tuberculosis (MTB) complex DNA in four of the individuals. In all cases the disease was caused by strains of Mycobacterium bovis rather than Mycobacterium tuberculosis and represents the first positive identification of the bovine form of the disease in archaeological human remains. Details of the palaeopathological characteristics of the cases are provided in the current paper, while the molecular observations are extended to include a quantitative evaluation of the surviving mycobacterial DNA using real-time PCR. The observation that bovine tuberculosis was the pathogen responsible is discussed in terms of current understanding of the evolution of the MTB complex as well as the implications for future ancient DNA studies in this area.

Age-dependent accumulation of lipofuscin in perivascular and subretinal microglia in experimental mice

Fundus autofluorescence (AF) imaging by confocal scanning laser ophthalmoscopy has been widely used by ophthalmologists in the diagnosis/monitoring of various retinal disorders. It is believed that fundus AF is derived from lipofuscin in retinal pigment epithelial (RPE) cells; however, direct clinicopathological correlation has not been possible in humans. We examined fundus AF by confocal scanning laser ophthalmoscopy and confocal microscopy in normal C57BL/6 mice of different ages. Increasingly strong AF signals were observed with age in the neuroretina and subretinal/RPE layer by confocal scanning laser ophthalmoscopy. Unlike fundus AF detected in normal human subjects, mouse fundus AF appeared as discrete foci distributed throughout the retina. Most of the AF signals in the neuroretina were distributed around retinal vessels. Confocal microscopy of retinal and choroid/RPE flat mounts demonstrated that most of the AF signals were derived from Iba-1+ perivascular and subretinal microglia. An age-dependent accumulation of Iba-1+ microglia at the subretinal space was observed. Lipofuscin granules were detected in large numbers in subretinal microglia by electron microscopy. The number of AF+ microglia and the amount of AF granules/cell increased with age. AF granules/lipofuscin were also observed in RPE cells in mice older than 12 months, but the number of AF+ RPE cells was very low (1.48 mm-2 and 5.02 mm-2 for 12 and 24 months, respectively) compared to the number of AF+ microglial cells (20.63 mm-2 and 76.36 mm-2 for 6 and 24 months, respectively). The fluorescence emission fingerprints of AF granules in subretinal microglia were the same as those in RPE cells. Our observation suggests that perivascular and subretinal microglia are the main cells producing lipofuscin in normal aged mouse retina and are responsible for in vivo fundus AF. Microglia may play an important role in retinal aging and age-related retinal diseases.

In Vivo Age Dependency of Unfractionated Heparin in Infants and Children

Introduction
Unfractionated Heparin (UFH) is used widely in paediatrics. Paediatric specific recommendations for UFH therapy are few, with the majority of recommendations being extrapolated from adult practice. In vitro studies have shown that this practice may be suboptimal. This study aimed to improve the understanding of the impact of age upon UFH response in vivo.

Materials and Methods
This prospective, observational study, conducted in the Paediatric Intensive Care Unit (PICU), included: patients 16 years or younger; treated with UFH of at least 10 U/Kg/hr. Laboratory analysis included: Antithrombin, APTT, Anti-Xa, Anti-IIa and thrombin generation expressed as the Endogenous Thrombin Potential. Results were grouped according to patient age (i.e. < 1, 1-5, 6-10 and 11-16 years).

Results
85 patients received an equivalent mean UFH dose with a median duration of 3 days. Antithrombin levels were decreased compared to age-related norms in children up to 11 years of age. APTT results were comparable across the age-groups. The Anti-Xa results using two different assays showed a trend for lower values in younger children. All children less than one year old recorded Anti-Xa values outside the therapeutic range for heparin therapy, for both assays. There was a trend for decreased Anti-IIa activity in younger children. Endogenous Thrombin Potential showed a significant trend for increased inhibition in older children. In vitro Antithrombin supplementation did not change the Anti-Xa or thrombin generation.

Conclusions
This study confirms that, in vivo, for the same dose of UFH, the anti Xa and anti IIa effect, as well as the inhibition of endogenous thrombin potential is age dependent and that these differences are not purely AT dependent. The implication is that the anticoagulant and antithrombotic effect of a given dose of UFH differs with age. Clinical outcome studies to determine the optimal dosing for each age group are warranted.

Abbreviations
UFH, Unfractionated Heparin; ETP, Endogenous Thrombin Potential; AT, Antithrombin; APTT, Activated Partial Thromboplastin Time