Digital Dementia Registry Bavaria-digiDEM Bayern: study protocol for a multicentre, prospective, longitudinal register study

INTRODUCTION

Dementia is one of the most relevant widespread diseases, with a prevalence of currently 50 million people with dementia worldwide. The care of people with dementia will be one of the major challenges for healthcare systems worldwide. Digitalisation offers new possibilities to improve both dementia healthcare and health outcomes research as a fundament for national healthcare planning. The 'Digital Dementia Registry Bavaria-digiDEM Bayern' aims to improve the understanding of the complexity and long-term progression of dementia and the current care situation in Bavaria. Moreover, by offering digital services, digiDEM will actively contribute to improving the care situation in Bavaria. METHODS AND ANALYSIS: digiDEM will recruit people with dementia and their family caregivers in all administrative regions of Bavaria. All participants will undergo dementia screening prior to study inclusion in order to identify people with mild cognitive impairment and mild-to-moderate dementia. Participants will be followed up over a period of three years. Sociodemographic data, type of dementia, symptoms, diagnosis, cognitive trajectories, activities of daily living, behavioural and psychological symptoms, falls, resource utilisation, caregiver burden, quality of life, needs of people with dementia and their caregivers, mobility, use of media and sources of information will be assessed. The project will implement a digital web-based platform for data collection. Data will be collected by means of standardised online or face-to-face interviews.

ETHICS AND DISSEMINATION

The study obtained ethical approval from the Ethics Committee of the Medical Faculty of Friedrich-Alexander-University Erlangen-Nürnberg (FAU) (application number: 253_20 B). Findings will be used for evidence-based decision-making for health decision-makers in order to optimise dementia healthcare in the state of Bavaria. Specific analyses will be conducted for the participating research partners. Results of the study will be published in peer-reviewed journals.

Nucleobindin 1 (NUCB1) is a Golgi-resident marker of neurons

Nucleobindin 1 (NUCB1; also known as CALNUC or NUC) is a putative DNA- and calcium-binding protein and exhibits significant structural homology with the protein nucleobindin 2 (NUCB2; also known as nesfatin). While NUCB2 has been mapped in detail in the brain and implicated in the hypothalamic control of energy metabolism, no study has to date addressed the presence of NUCB1 in the central nervous system. Here we have explored the expression and distribution of NUCB1 in the rat brain and spinal cord, using RT-PCR, immunofluorescence and in situ hybridization. NUCB1 mRNA and protein was found to be present in all brain regions, extending to the spinal cord and dorsal root ganglia. Double-staining for NUCB1 and NeuN, glial fibrillary acidic protein and myelin basic protein revealed that NUCB1 is exclusively found in neurons, and not in glial or ependymal cells. Notably, NUCB1-immunoreactivity was observed in all neurons examined, making no distinction between previously identified glutamatergic and GABAergic populations, including those that are known not to stain for NeuN. This included the markedly more restricted population of NUCB2-expressing neurons in the brain. The protein was detected in cell somata and proximal dendrites, but not in axons or terminal structures. Further examination of the subcellular distribution of NUCB1 using organelle-specific markers revealed its consistent presence in the Golgi apparatus. These findings identify NUCB1 as a novel pan-neuronal marker. Along with the recent demonstration of broad expression of the protein in endocrine cells, the present results suggest that NUCB1 may play a role in spatiotemporal calcium handling in signaling cells.

Altersabhängige Ansteuerung der Muskulatur im Stand bei Patienten mit Hämophilie

The haemophilic arthropathy affects the function of the knee joint muscles. The aim of this study was to investigate the myoelectrical signal of knee joint muscles in different age stages during upright standing. Surface EMG (SEMG) amplitudes of quadriceps, hamstrings and gastrocnemii were measured in 191 patients with severe haemophilia A (n=164) and B (n=27) while standing on an even surface. After an age-based classification of patients into the subgroups HA: 17–29 (n = 37), HB: 30–39 (n = 50), HC: 40–49 (n = 61), HD: 50–70 in years (n = 43) the clinical WFH score for the ankle and knee joint was determined. To normalize the SEMG values amplitude ratios (percentage of cumulated activity) were calculated with respect to the specific limb. With increasing age, the patient showed descriptively a deterioration of the joint situation. The extensors of the knee joint reached significantly higher absolute and percentage levels in the muscle activity with increasing age (p < 0.05). The absolute amplitude values of the Mm. gastrocnemii showed no differences in the age groups while the relative levels were decreased.

The present study shows that patients with increasing age and degree of haemophilic arthro pathy deve lop a modified control strategy during upright standing, in the form of a shift from the plantar flexors to the extensors of the knee joint.

Reciprocal effects of Interferon-γ and IL-4 on differentiation to osteoclast-like cells by RANKL or LPS

OBJECTIVE

LPS can induce differentiation to osteoclast-like cells independent of RANKL. In comparison with RANKL, the effects of Th1 and Th2 cytokines on LPS-induced osteoclastogenesis have not been extensively studied. In this study, we investigated the effects of IFN-γ and IL-4 on RANKL- or LPS-induced osteoclastogenesis.

MATERIALS AND METHODS

RAW 264.7 cells were induced to differentiate into osteoclast-like cells by RANKL or LPS, in the absence or presence of IFN-γ or IL-4. The number of TRAP-positive, multinucleated (≥ 3 nuclei) cells (MNCs) was counted. mRNA and protein levels of TRAP and cathepsin K were determined by quantitative RT-PCR and Western immunoblot, respectively. Expression of other genes implicated in osteoclast and macrophage differentiation and inflammation was also quantitated and was subsequently assessed in bone marrow-derived macrophages (BMMs). Phagocytic capacity of differentiated RAW264.7 was investigated by the uptake of pHrodo S. aureus bioparticles conjugates.

RESULTS

In contrast to the RANKL-treated cell population that gained more macrophage-like properties at the level of gene and protein expression as well as phagocytosis in the presence of IFN-γ or IL-4, the LPS-induced population gained more osteoclast-like properties by the addition of the same factors.

CONCLUSION

These data suggest that the adaptive immune system, through either Th1 or Th2 cytokines, is able to modify the differentiation process of osteoclasts in inflammatory situations. Moreover, the study provides an example of different regulation of osteoclast differentiation during physiological and inflammatory conditions.

Measurement of the neutron electric to magnetic form factor ratio at Q2=1.58 GeV2 using the reaction 3He[over →](e[over →],e'n)pp

A measurement of beam helicity asymmetries in the reaction 3He[over →](e[over →],e'n)pp is performed at the Mainz Microtron in quasielastic kinematics to determine the electric to magnetic form factor ratio of the neutron GEn/GMn at a four-momentum transfer Q2=1.58  GeV2. Longitudinally polarized electrons are scattered on a highly polarized 3He gas target. The scattered electrons are detected with a high-resolution magnetic spectrometer, and the ejected neutrons are detected with a dedicated neutron detector composed of scintillator bars. To reduce systematic errors, data are taken for four different target polarization orientations allowing the determination of GEn/GMn from a double ratio. We find μnGEn/GMn=0.250±0.058(stat)±0.017(syst).

Bone repair using periodontal ligament progenitor cell-seeded constructs

The success of tissue-engineering therapies is dependent on the ability of scaffolds to guide differentiation of progenitor cells. Here we present a new approach using a biomimetic construct composed of hydroxyapatite modified with an in vitro-derived extracellular matrix (HA-ECM) and seeded with periodontal ligament progenitor cells (PDLCs). The study aimed to investigate the effect of HA-ECM on osteogenic differentiation of PDLCs and in vivo evaluation of the PDLC-seeded HA-ECM constructs using a rat calvarial critical-sized defect model. After flow-cytometric phenotyping of PDLCs for typical mesenchymal stem cell markers, the PDLCs were cultured on HA-ECM or HA alone in osteogenic media and assessed by MTT, alkaline phosphatase (ALP) assays, and real-time qPCR at different time intervals after seeding. New bone formation induced by PDLC-seeded constructs was assessed by histomorphometric analysis at 12 weeks post-operatively. The PDLCs seeded on HA-ECM showed significantly higher ALP activity and up-regulation of bone-related genes. The treatment with PDLC-seeded HA-ECM significantly improved calvarial bone repair, with the highest amount of newly formed bone elicited by cell-seeded constructs cultured for 14 days. Our results highlight the PDLC-seeded HA-ECM constructs as a promising tool for craniofacial bone regeneration.

High-definition imaging of circulating tumor cells and associated cellular events in non-small cell lung cancer patients: a longitudinal analysis

Sampling circulating tumor cells (CTCs) from peripheral blood is ideally accomplished using assays that detect high numbers of cells and preserve them for downstream characterization. We sought to evaluate a method using enrichment free fluorescent labeling of CTCs followed by automated digital microscopy in patients with non-small cell lung cancer. Twenty-eight patients with non-small cell lung cancer and hematogenously seeded metastasis were analyzed with multiple blood draws. We detected CTCs in 68% of analyzed samples and found a propensity for increased CTC detection as the disease progressed in individual patients. CTCs were present at a median concentration of 1.6 CTCs ml⁻¹ of analyzed blood in the patient population. Higher numbers of detected CTCs were associated with an unfavorable prognosis.

Characterization of circulating tumor cell aggregates identified in patients with epithelial tumors

Circulating tumor cells (CTCs) have been implicated as a population of cells that may seed metastasis and venous thromboembolism (VTE), two major causes of mortality in cancer patients. Thus far, existing CTC detection technologies have been unable to reproducibly detect CTC aggregates in order to address what contribution CTC aggregates may make to metastasis or VTE. We report here an enrichment-free immunofluorescence detection method that can reproducibly detect and enumerate homotypic CTC aggregates in patient samples. We identified CTC aggregates in 43% of 86 patient samples. The fraction of CTC aggregation was investigated in blood draws from 24 breast, 14 non-small cell lung, 18 pancreatic, 15 prostate stage IV cancer patients and 15 normal blood donors. Both single CTCs and CTC aggregates were measured to determine whether differences exist in the physical characteristics of these two populations. Cells contained in CTC aggregates had less area and length, on average, than single CTCs. Nuclear to cytoplasmic ratios between single CTCs and CTC aggregates were similar. This detection method may assist future studies in determining which population of cells is more physically likely to contribute to metastasis and VTE.

Fluid biopsy for circulating tumor cell identification in patients with early-and late-stage non-small cell lung cancer: a glimpse into lung cancer biology

Circulating tumor cell (CTC) counts are an established prognostic marker in metastatic prostate, breast and colorectal cancer, and recent data suggest a similar role in late stage non-small cell lung cancer (NSCLC). However, due to sensitivity constraints in current enrichment-based CTC detection technologies, there are few published data about CTC prevalence rates and morphologic heterogeneity in early-stage NSCLC, or the correlation of CTCs with disease progression and their usability for clinical staging. We investigated CTC counts, morphology and aggregation in early stage, locally advanced and metastatic NSCLC patients by using a fluid-phase biopsy approach that identifies CTCs without relying on surface-receptor-based enrichment and presents them in sufficiently high definition (HD) to satisfy diagnostic pathology image quality requirements. HD-CTCs were analyzed in blood samples from 78 chemotherapy-naïve NSCLC patients. 73% of the total population had a positive HD-CTC count (>0 CTC in 1 mL of blood) with a median of 4.4 HD-CTCs mL⁻¹ (range 0-515.6) and a mean of 44.7 (±95.2) HD-CTCs mL⁻¹. No significant difference in the medians of HD-CTC counts was detected between stage IV (n = 31, range 0-178.2), stage III (n = 34, range 0-515.6) and stages I/II (n = 13, range 0-442.3). Furthermore, HD-CTCs exhibited a uniformity in terms of molecular and physical characteristics such as fluorescent cytokeratin intensity, nuclear size, frequency of apoptosis and aggregate formation across the spectrum of staging. Our results demonstrate that despite stringent morphologic inclusion criteria for the definition of HD-CTCs, the HD-CTC assay shows high sensitivity in the detection and characterization of both early- and late-stage lung cancer CTCs. Extensive studies are warranted to investigate the prognostic value of CTC profiling in early-stage lung cancer. This finding has implications for the design of extensive studies examining screening, therapy and surveillance in lung cancer patients.

[Analysis of muscle function with kinetic superficial EMG in children with haemophilia - recognizing subclinical changes, establishing individual therapy, quality control]

Electromyography (EMG) measures muscle electricity. It depends on muscle contraction and central motor control. Muscles react very sensitive on external signals (e. g. bleeding), The resulting changes can be shown in EMG.

PATIENTS, METHODS

A first study included 51 children and young adults from Costa Rica. They underwent a clinical examination and EMG of the hip, knee and ankle joints. Resting muscle tone, maximal isometric contraction and three typical isotonic movements of the joints were measured. First step of analysis was to characterize typical pathogenic changes in the muscles and to find a corresponding physical therapy to minimize these changes.

RESULTS

It showed that EMG is a good marker for muscle condition. It helps to individualize therapy and improve effectivity of physical and physiotherapeutic treatment of the locomotive system of children and young adults with hemophilia. It can help to recognize early subclinical changes and to control the outcome of therapeutic modalities.

Abstract 4151: High definition circulating tumor cells in patients with non-small cell lung cancer

Circulating tumor cell (CTC) counts are an established prognostic marker in metastatic prostate, breast, and colorectal cancer. However, there is little knowledge about CTC incidence rates and morphologic heterogeneity in non-small cell lung cancer (NSCLC) and their correlation to disease progression and usability for clinical staging. Here, we present a fluid phase biopsy approach that identifies CTCs without surface receptor-based enrichment, and presents them in sufficiently high definition (HD) to satisfy diagnostic pathology image quality requirements. The HD-CTC assay will be used to monitor HD-CTC counts and morphology in early stage, locally advanced, and metastatic NSCLC patient over time. 150 newly diagnosed NSCLC patients are being enrolled for this project. At the time of diagnosis 50 of the patients will have early stage cancers (stage I-II); 50 patients will have locally advanced (stage III) cancers, and 50 will be patients presenting with metastatic (stage IV) disease. Blood samples from each patient will be obtained at the time of diagnosis and 6 months later. We present here an interim data set that shows an incidence rate of 78% at baseline with a median CTC count of 19.5/ml of blood (range 0-441.6). Our preliminary data demonstrates that, despite stringent morphologic inclusion criteria for the definition of HD-CTCs, our HD-CTC assay shows high sensitivity in the detection of lung cancer CTCs.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr 4151. doi:10.1158/1538-7445.AM2011-4151

Abstract 5225: Quantification of circulating tumor cell aggregates in breast cancer patient blood using an enrichment-free detection method

Circulating tumor cells (CTCs) have been implicated as a potential population of cells that may seed metastasis in cancer patients. In order to characterize and understand this population of cells, an enrichment-free immunofluorescence detection method was developed by our lab. This method take whole patient blood and classifies cells based on cytokeratin (CTCs) and CD45 (WBCs) antibody staining. Using this CTC detection method, a population of cells residing in tumor cell aggregates was observed in blood draws from Stage IV breast cancer patients. It was previously observed in ex vivo mouse experiments that homotypic aggregate formation of tumor cells may increase metastatic efficiency (Glinsky, et al., Cancer Research, 2003). In this work, we seek to determine if a significant proportion of CTCs reside in homotypic aggregates in patient blood by enumerating CTC aggregates from the blood draws of 23 Stage IV breast cancer patients and 16 healthy donor patients. Preliminary analysis measuring associations of CTCs with other nucleated cells found in patient blood draws revealed that ∼43% of cytokeratin-positive (CK+) cells found in breast cancer patient samples localize with either other CK+ or white blood cells (WBCs) versus 14% in healthy donor patient samples. Furthermore, ∼19% of WBCs were found to be associated with either CK+ or other WBCs in breast cancer patient samples versus ∼7% in healthy donor patient samples. Pathological review confirming CK+ cells as CTCs revealed that of the CTCs detected in patient blood after pathological review, ∼2% of CTCs were found as homotypic aggregates versus ∼0.07% in healthy donor samples (p=0.0005). Four breast cancer patients were found to have no CTC aggregates. Two breast cancer patients had significantly higher than average CTC aggregate percentages (∼6% and ∼7%). Patients will continue to be monitored to measure any differences in disease outcome of patients with high incidence of CTC aggregates versus patients with low incidence of CTC aggregates and healthy donors.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr 5225. doi:10.1158/1538-7445.AM2011-5225

Muskelfunktionsmessung mit kinetischem Oberflächen-EMG bei Kindern mit Hämophilie

Electromyography (EMG) measures muscle electricity. It depends on muscle contraction and central motor control. Muscles react very sensitive on external signals (e. g. bleeding), The resulting changes can be shown in EMG.

Patients, methods A first study included 51 children and young adults from Costa Rica. They underwent a clinical examination and EMG of the hip, knee and ankle joints. Resting muscle tone, maximal isometric contraction and three typical isotonic movements of the joints were measured. First step of analysis was to characterize typical pathogenic changes in the muscles and to find a corresponding physical therapy to minimize these changes.

Results It showed that EMG is a good marker for muscle condition. It helps to individualize therapy and improve effectivity of physical and physiotherapeutic treatment of the locomotive system of children and young adults with hemophilia. It can help to recognize early subclinical changes and to control the outcome of therapeutic modalities.

Regulatory T cells control macrophage accumulation and activation in lymphoma

Strategies of manipulating immunosuppressive regulatory T cells (Treg) in cancer patients are currently evaluated in clinical trials. Treg suppress immune responses of tumor-specific T cells; yet, relatively little is known about the impact of Treg on innate immune cells in tumor models in vivo. Many tumors lose expression of MHC class I. Therefore, our study aimed at defining strategies to strengthen immune responses against a high tumor burden of the MHC class I-deficient mouse lymphoma RMA-S. We demonstrate that Treg depletion in mice led to tumor rejection that was dependent on T cells, NK cells and IFN-gamma. In the absence of Treg elevated levels of IFN-gamma were produced by tumor-infiltrating T cells and NK cells. Tumor rejection observed in the absence of Treg correlated with a substantial IFN-gamma-dependent increase in the numbers of tumor-infiltrating leukocytes. The most abundant cell population in the tumors was macrophages. Tumor-infiltrating macrophages from Treg-depleted mice expressed increased amounts of MHC class II, produced highly enhanced levels of pro-inflammatory cytokines and inhibited tumor cell proliferation. It was reported that tumor-infiltrating macrophages have multi-faceted functions promoting or counteracting tumor growth. In our study, high numbers of macrophages infiltrating RMA-S tumors in the absence of Treg correlated with tumor rejection suggesting that macrophages are additional targets for Treg-mediated immune suppression in cancer.

TGF-beta/extracellular matrix interactions in dentin matrix: a role in regulating sequestration and protection of bioactivity

TGF-beta isoforms sequestrated in dentin matrix potentially provide a reservoir of bioactive molecules that may influence cell behavior in the dentin-pulp complex following tissue injury. The association of these growth factors with dentin matrix and the influence of such associations on the bioactivity of growth factors are still unclear. We used surface plasmon resonance technology in the BIAcore 3000 system to investigate the binding of TGF-beta isoforms 1 and 3 to purified decorin, biglycan, and EDTA soluble dentin matrix components. TGF-beta isoforms 1 and 3 were immobilized on sensorchips CM4 through amine coupling. For kinetic studies of protein binding, purified decorin and biglycan, isolated EDTA soluble dentin matrix, and dentin matrix immunodepleted of decorin and/or biglycan were injected over TGF-beta isoforms and allowed to interact. Programmed kinetic analysis software provided sensorgrams for each concentration of proteoglycan or dentin matrix extract injected. Purified decorin and biglycan and dentin matrix extract bound to the TGF-beta isoforms. However, the association with TGF-beta3 was much weaker than that with TGF-beta1. After immunoaffinity depletion of the dentin matrix extract, the level of interaction between the dentin matrix extract and TGF-beta was significantly reduced. These results suggest isoform-specific interactions between decorin/biglycan and TGF-beta isoforms 1 and 3, which may explain why TGF-beta3 is not detected in the dentin matrix despite being expressed at higher levels than TGF-beta1 in odontoblasts. These proteoglycans appear to play a significant role in TGF-beta/extracellular matrix interactions and may be important in the sequestration of these growth factors in the dentin matrix.

Natural killer cell accumulation in tumors is dependent on IFN-gamma and CXCR3 ligands

Several studies have correlated high numbers of tumor-infiltrating natural killer (NK) cells with a good prognosis for cancer patients. Our study aimed at identifying factors controlling intratumoral NK cell accumulation in s.c. injected NK cell sensitive tumor models and at studying their effect on survival time of recipient mice. We observed that fewer NK cells infiltrated the tumors in IFN-gamma receptor knockout (IFN-gammaR(-/-)) mice compared with wild-type controls that correlated with decreased survival rate. Exogenous application of IFN-gamma in the tumor augmented levels of ligands of the chemokine receptor CXCR3, increased NK cell accumulation, and prolonged survival. Furthermore, our data show that CD27(high) NK cells, which under steady-state conditions express CXCR3, preferentially accumulated in the tumor tissue. Accordingly, significantly lower numbers of tumor-infiltrating NK cells were detected in CXCR3(-/-) mice, and the capacity of adoptively transferred CXCR3(-/-) NK cells to accumulate in the tumor was severely impaired. Finally, exogenous application of the CXCR3 ligand CXCL10 in the tumor or ectopic expression of CXCL10 by tumor cells increased the numbers of NK cells in the tumors and prolonged NK cell-dependent survival. Our results identify IFN-gamma and the expression of CXCR3 on NK cells as prerequisites for NK cell infiltration into tumors. Exploiting strategies to augment NK cell accumulation in the tumor might lead to the development of effective antitumor therapies.

Adenosine A1 and A2 receptor agonists reduce endotoxin-induced cellular energy depletion and oedema formation in the lung

BACKGROUND AND OBJECTIVE

Tissue depletion of adenosine during endotoxaemia has previously been described in the lung. Therapeutic approaches to prevent adenosine depletion and the role of A1 and A2 receptor agonists, however, have not been investigated until now.

METHODS

In isolated and ventilated rabbit lungs, it was tested whether pretreatment with adenosine A1 agonist 2-chloro-N6-cyclopentyladenosine (CCPA; 10(-7) mol, n = 6) or A2 receptor agonist 5'-(N-cyclopropyl)-carboxyamido adenosine (CPCA; 10(-7) mol, n = 6) prior to injection of lipopolysaccharide (LPS) (500 pg mL-1) influenced pulmonary artery pressure (PAP), pulmonary energy content and oedema formation as compared with controls, solely infused with LPS (n = 6). Release rates of adenosine and uric acid were determined by high-performance liquid chromatography. Pulmonary tissue concentrations of high-energy phosphates were measured and the adenine nucleotide pool, adenosine 5'-triphosphate (ATP)/adenosine 5'-diphosphate (ADP) ratio and adenylate energy charge of the pulmonary tissue were calculated.

RESULTS

Administration of LPS induced increases in PAP within 2 h up to 20.8 +/- 2.9 mmHg (P < 0.01). While pretreatment with the A1 agonist merely decelerated pressure increase (13.8 +/- 1.1 mmHg, P < 0.05), the A2 agonist completely suppressed the pulmonary pressure reaction (9.6 +/- 1.0 mmHg, P < 0.01). Emergence of lung oedema after exclusive injection of LPS up to 12.0 +/- 2.9 g was absent after A1 (0.6 +/- 0.5 g) and A2 (-0.3 +/- 0.2 g) agonists. These observations were paralleled by increased adenosine release rates compared with LPS controls (P < 0.05). Moreover, tissue concentrations of ADP, ATP, guanosine 5'-diphosphate, guanosine 5'-triphosphate, nicotinamide-adenine-dinucleotide and creatine phosphate were significantly reduced after LPS. Consequently, the calculated tissue adenine nucleotide pool and the adenylate energy charge increased after adenosine receptor stimulation (P = 0.001).

CONCLUSIONS

Adenosine A1- and A2-receptor agonists reduced LPS-induced vasoconstriction and oedema formation by maintenance of tissue energy content. Thus, adenosine receptor stimulation, in particular of the A2 receptor, might be beneficial during acute lung injury.

Expression of HMGB1 during tooth development

High mobility group box 1 (HMGB1) is a nuclear and cytosolic protein that can act as a transcription factor, a growth factor, or a cytokine. To elucidate a possible role for HMGB1 in tooth development, we have studied the expression of HMGB1 and its receptor RAGE (receptor for advanced glycation end-products) during the late fetal and early postnatal period of rat by using light- and electron-microscopic immunohistochemistry. Low HMGB1 protein expression was observed during fetal and newborn stages of tooth development. However, from postnatal day 5 (P5) onward, a marked increase occurred in the levels of the protein in most dental cell types. Expression was particularly high in ameloblasts and odontoblasts at regions of ongoing mineralization. Although most HMGB1 immunoreactivity was confined to cell nuclei, it was also present in odontoblast cytoplasm. At P5, ameloblasts and odontoblasts also showed RAGE immunoreactivity, and reverse transcription-polymerase chain reaction demonstrated both HMGB1 and RAGE mRNA in human dental pulp cells in vitro. Immunoblots performed on extracts from bovine dentin demonstrated a principal band at approximately 27 kDa, indicating that HMGB1 participates in tooth mineralization. The expression of both ligand and receptor suggests an autocrine/paracrine HMGB1 signalling axis in odontoblasts.

Amelotin--a Novel Secreted, Ameloblast-specific Protein

We aimed to analyze the differential gene expression in various murine dental tissues, expecting to find novel factors that are involved in tooth formation. We here describe the identification of a novel ameloblast-specific gene, amelotin (AMTN), by differential display polymerase chain-reaction (DD-PCR) analysis of microdissected ameloblasts, odontoblasts, dental pulp, and alveolar bone cells of 10-day-old mouse incisors. The conceptually translated protein sequence was unique and showed significant homology only with its human orthologue. The amelotin genes from mouse and human displayed a similar exon-intron structure and were expressed from loci on chromosomes 5 and 4, respectively, which have been associated with various forms of amelogenesis imperfecta. Expression of amelotin mRNA was restricted to maturation-stage ameloblasts in developing murine molars and incisors. Amelotin protein was efficiently secreted from transfected cells in culture. Taken together, our findings suggest that amelotin is a novel factor produced by ameloblasts that plays a critical role in the formation of dental enamel.

The hyalectan degrading ADAMTS-1 enzyme is expressed by osteoblasts and up-regulated at regions of new bone formation

During bone formation, there are numerous pivotal changes in the interrelationships between osteoblasts and molecules of the extracellular matrix (ECM). Consequently, the mechanisms that underlie the temporal and spatial distribution of ECM molecules in bone are of considerable interest in understanding its formation. A subfamily of a disintegrin and metalloproteinase (ADAMs) has been identified, which contain thrombospondin-like motifs (ADAMTS), and can break down several ECM molecules. Using reversed transcribed PCR, we identified ADAMTS-1, -4 and -5 mRNA expression in cultures of rat osteoblasts treated with ascorbic acid, beta-glycerophosphate and dexamethasone, molecules known to drive osteoblast differentiation. Of these, ADAMTS-1 followed most closely the osteogenic marker osteocalcin during in vitro mineralisation. Consequently, we studied, in detail, protein expression of ADAMTS-1 during in vitro osteogenesis together with ADAMTS-1 immunohistochemistry staining of sections from 2- and 10-day-old rat femur. Western analysis of osteoblast proteins showed ADAMTS-1 products that correspond well with both full-length and furin-processed species. In the ECM laid down by osteoblasts, only the mature secreted protein (approximately 90 kDa) and its accumulation during the later stages of osteogenesis in vitro were noticed. Furthermore, immunostaining with an antibody recognising ADAMTS-1 demonstrated strong expression around mineralised nodules and intense focal staining of putative new areas of nodule formation in vitro. Finally, immunohistochemistry of 2- and 10-day-old rat femur localised ADAMTS-1 protein to regions associated with osteogenesis. These data show that ADAMTS-1 protein accumulates in osteoblast ECM during differentiation. Furthermore, the focalised expression of ADAMTS-1 in regions of osteogenesis, both in vitro and in vivo, implicates this multifunctional protein to be involved in mineralised nodule and bone formation.

Nucleobindin--a Ca2+-binding protein present in the cells and mineralized tissues of the tooth

Nucleobindin, a Ca2+-binding protein, has been previously identified within the nucleus and endoplasmic reticulum, and in association with the Golgi membrane. In addition, nucleobindin has been shown to be a minor constituent of bone extracellular matrix and has been postulated to play a role in mineralization. In the current investigation, we report the expression and localization of nucleobindin within odontoblasts and the dentin matrix. Nucleobindin mRNA transcripts were detected in the tooth, and in situ hybridization analysis substantiated the findings, showing nucleobindin expression within mature odontoblasts and within the cells of surrounding developing alveolar bone. Western blot analysis of tooth protein extracts demonstrated the presence of a 63 kDa protein, which showed immunologic affinity for a rat nucleobindin peptide antibody. The distribution of the protein was shown in mature odontoblasts by using immunohistochemistry. Moreover, immunogold labeling of nucleobindin and subsequent ultrastructural analysis demonstrated a similar pattern of distribution. Nucleobindin was identified within odontoblast cellular compartments: the nucleus, endoplasmic reticulum, and mitochondria. Of interest, nucleobindin localization was observed within the surrounding dentin extracellular matrix, and immunogold labeling was shown to accumulate with tissue development toward the cusp. The study clearly demonstrated the presence of nucleobindin within dental tissues. In consideration of the known functional properties of nucleobindin, it may be postulated that nucleobindin may contribute to the accumulation and transport of Ca2+ ions to the mineralization front prior to hydroxyapatite deposition.

Ultrastructural distribution of osteoadherin in rat bone shows a pattern similar to that of bone sialoprotein

Osteoadherin (OSAD) is a keratan sulfate proteoglycan recently isolated from bovine and rat bone. Based on results obtained from in vitro experiments, the protein was shown to bind osteoblasts via the integrin receptor alpha v beta 3. Due to OSAD's capacity to bind hydroxyapatite crystals, a role for the protein in the mineralization process has also been suggested. To test these hypotheses in an in vivo model, the ultrastructural localization of OSAD in bone, tibial (metaphyses and diaphyses), and calvarial samples from normal 10 to 12-day-old rats were examined by immunohistochemical techniques at the ultrastructural level. In addition to the qualitative studies, quantitative measurements of OSAD marker density were performed in relevant compartments. Immunolabeling for OSAD was located to the mineralized bone matrix, with highest concentration of marker at the border between bone and cartilage remnants in the metaphyseal trabeculi. Intracellular labeling was low and no systemic accumulation of OSAD markers was observed at the cell-matrix interface. The observed distribution pattern of OSAD is strikingly similar to that of bone sialoprotein (BSP), confirmed by double labeling. The results of the current study support a role for OSAD in the mineralization process. In this process BSP is assumed to be a nucleator of hydroxyapatite crystals, and OSAD could work in concert with BSP to regulate nucleation. However, the mechanisms involved remain to be elucidated.

Recurrent peritoneal mesothelioma with long-delayed recurrence

Peritoneal mesothelioma is a rare malignancy with a poor prognosis. Etiology is unclear and presentation of this disease is often atypical. There are very few cases of long-term survival in patients with peritoneal mesothelioma. We report the case of a patient with peritoneal mesothelioma of 19 years' duration. To the best of our knowledge, there have been no reports of recurrent peritoneal mesothelioma with such long-delayed recurrence and survival. Recurrent peritoneal mesothelioma in the current patient was confirmed by comparing the biopsies of omentum taken in 1979 with that taken in 1997. An extensive literature search was undertaken to look for previous reports of recurrent peritoneal mesothelioma. Aggressive and intensive chemotherapy appeared to provide a longer survival time. Our patient had paraneoplastic manifestations that included paraneoplastic hepatopathy and a wasting syndrome. Peritoneal mesothelioma is a rare malignancy with one to two cases per million in the United States. It is known to exhibit unusual paraneoplastic manifestations, including paraneoplastic hepatopathy. Treatment is often unsuccessful, with a median survival time of approximately 18 months from diagnosis. A better understanding and aggressive management of this disease appear to help prolong survival.

Osteoadherin, a cell-binding keratan sulfate proteoglycan in bone, belongs to the family of leucine-rich repeat proteins of the extracellular matrix

Osteoadherin is a recently described bone proteoglycan containing keratan sulfate. It promotes integrin (alphav beta3)-mediated cell binding (Wendel, M., Sommarin, Y., and Heinegârd, D. (1998) J. Cell Biol. 141, 839-847). The primary structure of bovine osteoadherin has now been determined by nucleotide sequencing of a cDNA clone from a primary bovine osteoblast expression library. The entire translated primary sequence corresponds to a 49,116-Da protein with a calculated isoelectric point for the mature protein of 5.2. The dominating feature is a central region consisting of 11 B-type, leucine-rich repeats ranging in length from 20 to 30 residues. The full, primary sequence contains four putative sites for tyrosine sulfation, three of which are at the N-terminal end of the molecule. There are six potential sites for N-linked glycosylation present. Osteoadherin shows highest sequence identity, 42%, to bovine keratocan and 37-38% identity to bovine fibromodulin, lumican, and human PRELP. Unique to osteoadherin is the presence of a large and very acidic C-terminal domain. The distribution of cysteine residues resembles that of other leucine-rich repeat proteins except for two centrally located cysteines. Northern blot analysis of RNA samples from various bovine tissues showed a 4.5-kilobase pair message for osteoadherin to be expressed in bone only. Osteoadherin mRNA was detected by in situ hybridization in mature osteoblasts located superficially on trabecular bone.

Bone matrix proteins: isolation and characterization of a novel cell-binding keratan sulfate proteoglycan (osteoadherin) from bovine bone

A small cell-binding proteoglycan for which we propose the name osteoadherin was extracted from bovine bone with guanidine hydrochloride-containing EDTA. It was purified to homogeneity using a combination of ion-exchange chromatography, hydroxyapatite chromatography, and gel filtration. The Mof the proteoglycan was 85, 000 as determined by SDS-PAGE. The protein is rich in aspartic acid, glutamic acid, and leucine. Two internal octapeptides from the proteoglycan contained the sequences Glu-Ile-Asn-Leu-Ser-His-Asn-Lys and Arg-Asp-Leu-Tyr-Phe-Asn-Lys-Ile. These sequences are not previously described, and support the notion that osteoadherin belongs to the family of leucine-rich repeat proteins. A monospecific antiserum was raised in rabbits. An enzyme-linked immunosorbent assay was developed, and showed the osteoadherin content of bone extracts to be 0.4 mg/g of tissue wet weight, whereas none was found in extracts of various other bovine tissues. Metabolic labeling of primary bovine osteoblasts followed by immunoprecipitation showed the cells to synthesize and secrete the proteoglycan. Digesting the immunoprecipitated osteoadherin with N-glycosidase reduced its apparent size to 47 kD, thus showing the presence of several N-linked oligosaccharides. Digestion with keratanase indicated some of the oligosaccharides to be extended to keratan sulfate chains. In immunohistochemical studies of the bovine fetal rib growth plate, osteoadherin was exclusively identified in the primary bone spongiosa. Osteoadherin binds to hydroxyapatite. A potential function of this proteoglycan is to bind cells, since we showed it to be as efficient as fibronectin in promoting osteoblast attachment in vitro. The binding appears to be mediated by the integrin alphavbeta3, since this was the only integrin isolated by osteoadherin affinity chromatography of surface-iodinated osteoblast extracts.

Serine protease of hepatitis C virus expressed in insect cells as the NS3/4A complex

Hepatitis C virus (HCV) protease NS3 and its protein activator NS4A participate in the processing of the viral polyprotein into its constituent nonstructural proteins. The NS3/4A complex is thus an attractive target for antiviral therapy against HCV. We expressed the full-length NS3 and NS4A in insect cells as a soluble fusion protein with an N-terminal polyhistidine tag and purified the two proteins to homogeneity. Cleavage at the junction between HisNS3 and NS4A occurs during expression, producing a noncovalent complex between HisNS3 and NS4A with a subnanomolar dissociation constant. We purified the HisNS3/4A complex by detergent extraction of cell lysate and by metal chelate chromatography. We removed the His tag by thrombin cleavage and then further purified the complex by gel filtration. The purified NS3/4A complex is active in a protease assay using a synthetic peptide substrate derived from the NS5A-NS5B junction, with kcat/K(m) of 3700 (+/- 600) M-1 s-1, an order of magnitude above those previously reported for NS3 expressed by other strategies. This high protease activity implies that the full-length sequences of NS3 and NS4A are required for optimal activity of the NS3 protease domain. We examined the dependence of the NS3/4A protease activity on buffer conditions, temperature, and the presence of detergents. We find that, under most conditions, NS3 protease activity is dependent on the aggregation state of the NS3/4A complex. The monodisperse, soluble form of the NS3/4A complex is associated with the highest protease activity.

Mouse models for extracellular matrix diseases

Mutations of a number of genes encoding for extracellular matrix (ECM) proteins in mice have provided new insights regarding their role during development and disease. Many mouse strains have helped to verify the link between mutation and disease in humans, and others have produced unexpected phenotypes and identified new functions for ECM proteins. Finally, some null mutations in ECM genes provide no phenotypic alterations in mice, confronting the scientific community with a new challenge to search for their functions. This review lists all mouse strains with spontaneous and experimentally induced mutations in ECM genes. The phenotypes of these mice are discussed in comparison with the human diseases.

Cartilage matrix macromolecules in lavage fluid of temporomandibular joints before and 6 months after diskectomy

The purpose was to investigate if antigenic fragments of aggrecan and cartilage oligomeric matrix protein (COMP) are detectable by enzyme-linked immunosorbent assay in lavage fluids from the temporomandibular joint (TMJ) and to examine if the relative content of these cartilage markers changes during development of osteoarthrosis (OA) after diskectomy. Lavage fluid was obtained at surgery and 6 months postoperatively in 13 patients. Computed tomography or magnetic resonance imaging was without evidence of hard-tissue changes prior to surgery in all patients. In 9 of the patients, sufficient material for analysis was obtained at both examinations. Aggrecan and COMP were detectable in all but 2 fluids, in which the COMP levels were below detection limit. The aggrecan/COMP ratio increased in all 9 patients during the 6-month period, indicating increased release of aggrecan relative to COMP fragments. The changed aggrecan/COMP ratio possibly reflects increased cartilage turnover during development of OA. Changes compatible with OA were present on computed tomography in all cases at the 6-month follow-up. This study shows that the lavage procedure is feasible for obtaining synovial fluid from the TMJ for immunochemical analyses of tissue-derived macromolecules.

Enhancement of hepatitis C virus NS3 proteinase activity by association with NS4A-specific synthetic peptides: identification of sequence and critical residues of NS4A for the cofactor activity

The NS3 proteinase of hepatitis C virus utilizes NS4A as a cofactor for cleavages at four sites (3/4A, 4A/4B, 4B/5A, and 5A/5B) in the nonstructural region of the viral polyprotein. To characterize NS4A for its role in modulating the NS3 proteinase activity at various cleavage sites, synthetic peptides spanning various parts of NS4A were synthesized and tested in a cell-free trans-cleavage reaction using purified NS3 proteinase domain and polyprotein substrates. The NS3 proteinase domain was expressed in Escherichia coli, purified, denatured, and refolded to an enzymatically active form. We found that a 12-amino-acid peptide containing amino acid residues 22 to 33 in NS4A (CVVIVGRIVLSG) was sufficient for cofactor activity in NS3-mediated proteolysis. The peptide enhanced the cleavage at the NS5A/5B site and was necessary for NS3-mediated cleavage at NS4A/4B and NS4B/5A. Sequential amino acid substitution within the designated peptide identified residues I29 and I25 as critical for potential cofactor activity. We provide evidence that the NS4A peptide and the NS3 catalytic domain form an enzymatically active complex. These data suggest that the central 12-amino-acid peptide (aa 22-33) of NS4A is primarily important for the cofactor activity through complex formation with NS3, and the interaction may represent a new target for antiviral drug development.

Isolation, characterization, and primary structure of a calcium-binding 63-kDa bone protein

A novel noncollagenous protein of the mineralized matrix of bovine bone was isolated by ion exchange and gel permeation chromatography. The apparent M(r) of the protein is 63,000 as determined by SDS-polyacrylamide gel electrophoresis. The protein is a rather minor constituent in bone and could not be detected in other connective tissues by enzyme-linked immunosorbent assay of guanidine HCl extracts. The 63-kDa protein was detected in the osteoid and around the osteocytes upon immuno-histochemical staining of bovine compact bone. The sequence of the 63-kDa protein was deduced from cDNA clones isolated from a rat calvaria lambda gt11 expression library. The protein contains two centrally located EF-hand Ca(2+)-binding domains. Seven heptad repeats are present indicating the ability of the protein for coiled-coil interactions. Ability to bind calcium was confirmed by 45Ca2+ binding to protein blotted onto nitrocellulose membrane. The protein was synthesized in calvaria explants as detected by immunoprecipitation of radiolabeled protein from the culture medium. Although the protein can be detected in biochemical amounts in bone only, varying amounts of mRNA for this protein were detected in several rat tissues by RNase protection assay with highest levels in rat calvaria. This extracellular protein corresponds to a mouse protein called nucleobindin.

Purification of a bone sialoprotein-binding protein from Staphylococcus aureus

Bone sialoprotein (BSP) is selectively bound by Staphylococcus aureus cells isolated from patients suffering from infections of bone and joint tissues [Rydén C., Maxe, I., Franzén, A., Ljungh, A., Heinegård, D. & Rubin, K. (1987) Lancet II, 515]. We now report on the purification of a cell-wall protein from Staphylococcus aureus, strain O24, that possesses affinity for bone sialoprotein. Staphylococcal cell-wall components with capacity to inhibit binding of 125I-labeled BSP to staphylococcal cells were solubilized with LiCl (1.0 M, pH 5.0). Preparative SDS/PAGE and protein-overlay experiments revealed that inhibitory activity present in LiCl extracts resided in a fraction of polypeptides with M(r) 75,000-110,000. Staphylococcal proteins solubilized with LiCl were chromatographed on a Mono-Q anion-exchange column. Inhibitory activity was eluted at 0.6-0.8 M NaCl and could be further purified by affinity chromatography on BSP-Sepharose. Elution of the affinity matrix with 0.1 M glycine, pH 3.0, specifically eluted inhibitory activity. Analysis by SDS/PAGE revealed a single M(r) 97,000 polypeptide in the eluate. The purified M(r) 97,000 protein bound BSP in protein-overlay experiments. LiCl extracts from S. aureus, strain E514 or Staphylococcus epidermidis, strain 7686, both lacking the capacity to bind BSP did not contain the M9r) 97,000 protein. Our data demonstrate the presence of a S. aureus cell-surface BSP-binding protein. This protein could be involved in bacterial tropism in osteomyelitis.

Dephosphorylation of osteopontin and bone sialoprotein by osteoclastic tartrate-resistant acid phosphatase. Modulation of osteoclast adhesion in vitro

The tartrate-resistant acid phosphatase (TRAP) of skeletal osteoclasts was found to partially dephosphorylate the bone matrix phosphoproteins osteopontin (OPN) and bone sialoprotein (BSP). TRAP also partially dephosphorylated metabolically [32P]PO4-labeled OPN as well as BSP, whereas comparable amounts of either alkaline phosphatase or prostatic acid phosphatase, at their respective pH optima, were ineffective, indicating a certain preference of TRAP for these phosphoprotein substrates. It has previously (Flores, M., Norgärd, M., Heinegård, D., Reinholt, F. P., and Andersson, G. (1992) Exp. Cell Res. 201, 526-530) been shown that osteoclasts bind to OPN as well as to BSP coated onto glass. We can now show that the partially dephosphorylated proteins no longer support osteoclast binding. These results indicate that the secretion of TRAP from osteoclasts into the resorption area could exert a regulatory influence on the attachment of the cells to the bone surface. This could imply roles in the development of ruffled borders and/or in the regulation of osteoclast motility on the bone surface.

Distribution and synthesis of bone sialoprotein in metaphyseal bone of young rats show a distinctly different pattern from that of osteopontin

Bone sialoprotein (BSP) and osteopontin (OPN) are two phosphorylated and highly glycosylated cell-binding proteins in bone. Both proteins bind to hydroxylapatite. The cell binding is mediated via an Arg-Gly-Asp (RGD) sequence and previous work indicates that both proteins can bind to the vitronectin receptor (alpha v beta 3). The present work shows that a prevailing localization of BSP in metaphyseal bone of the young rat is at the interface between calcified cartilage and bone. Thus BSP shows a conspicuous enrichment in the osteoid laid down by the invading osteoblasts immediately next to the calcified cartilage. Furthermore, the most prominent amount of BSP mRNA was detected in cells at the epiphyseal/metaphyseal border. As opposed to OPN, no prominent accumulation of BSP immunoreactivity was observed at bone surfaces that face cells. Also the synthesis OPN was most pronounced at sites very different from those of BSP. Thus, the most prominent amount of OPN mRNA was observed in cells close to the metaphyseal/diaphyseal border, where osteoclastic bone resorption is particularly active. Indeed, message was often found in cells surrounding osteoclasts without any detectable message. The distinctly different patterns of synthesis and expression of the two proteins indicate different roles in bone turnover at this stage of development. Thus, it appears that BSP has a specific role during the initial phases of bone formation at the cartilage/bone interface. On the other hand, the pattern of OPN synthesis and expression support and extend our previous data showing OPN particularly enriched at attachment sites of osteoclasts resorbing bone.

A major non-collagenous 62 kDa protein from rat bone mineralized matrix is identical to pp63 a phosphorylated glycoprotein from liver

A protein present as a M(r) 62 k monomer and as several differently sized disulfide-bonded oligomers has been isolated from rat bone mineralized matrix. Its overall tissue distribution determined by ELISA immunoassays showed the protein present only in bone, tooth and in serum while aorta, cartilage, intestine, kidney, liver, muscle, skin, spleen and tendon were all negative. Despite that the 62 kDa protein was abundant and selectively found in bone, no positive cDNA clone could be identified in several rat bone libraries. Positive clones were, however, identified in a rat liver expression library. A cDNA clone of 1.3 kb hybridized in a Northern blotting assay to a 1.8 kb mRNA in rat liver. No hybridization signal was detected with RNA from bone, brain, lung, muscle, spleen and kidney. Sequence analysis of the isolated cDNA clone revealed a 50-bp untranslated region followed by an open reading frame of 357 amino acids. The open reading frame can be divided into a 17-amino acid signal peptide followed by the mature protein of 340 amino acids with alanine as its N-terminal amino acid. A short N-terminal amino acid sequence from the isolated 62-kDa bone protein verified the molecular identity of the cDNA clone. The primary structure of the 62-kDa liver protein was identical to a that of a 63-kDa phosphorylated glycoprotein (pp63) from liver.

Cartilage matrix proteins. An acidic oligomeric protein (COMP) detected only in cartilage

An Mr = 524,000 oligomeric protein was isolated from bovine cartilage and designated COMP (Cartilage Oligomeric Matrix Protein). The protein is composed of disulfide-bonded subunits with an apparent Mr of 100,000 each. It is markedly anionic, probably due to its high contents of aspartic acid and glutamic acid, as well as to its substitution with negatively charged carbohydrates. COMP was found in all cartilages analyzed, but could not be detected in other tissues by enzyme-linked immunosorbent assay of guanidine HCl extracts. Within a given cartilage, COMP shows a preferential localization to the territorial matrix surrounding the chondrocytes.

Regenerative response to membranous and enchondral lyophilized allogeneic bone in rabbit skull defects

The regenerative responses of inlays of lyophilized allogeneic bone of membranous (skull) and enchondral (tibia) origin were studied in an experimental cranioplasty model in rabbits. The lyophilized bone particles were also bioassayed for inductive bone production in an orthotopic critical size defect rat model. Three trephined calvarial defects were evaluated in each of 14 adult rabbits. The experimental materials were implanted into two of the defects and the third was left empty for control purposes. The implants disclosed no major structural divergences as assessed by scanning electron microscopy. Healing was evaluated by light microscopy and contact radiography after periods of four and 15 weeks. The lyophilized bone allografts of both embryonic origins displayed a similar fashion of bone regeneration, bone marrow reappearance, and volumetric density of trabecular bone substance and displayed no obvious differences between experimental groups or intervals. The two materials exhibited low osteoinductive potential.

Cartilage matrix proteins. A basic 36-kDa protein with a restricted distribution to cartilage and bone

A non-collagenous quantitatively prominent protein was purified from guanidine hydrochloride extracts of bovine tracheal cartilage. Purification was achieved by cesium chloride density gradient centrifugation and chromatography on DEAE-cellulose at pH 7.0 followed by CM-cellulose at pH 5.0. The protein has a marked tendency to form aggregates in denaturing solutions of high ionic strength, e.g. 6 M guanidine hydrochloride. The purified protein contains a single, Mr 36,000 polypeptide chain, with a particularly high content of leucine. It contains about 1% carbohydrate with a remarkable absence of hexosamines and sialic acid, whereas xylose, galactose, mannose, and fucose were identified in the preparation. The protein was identified in extracts of cartilage and bone and could be shown to be primarily extracellular. Tendon may contain trace amounts of the protein, whereas extracts of several other tissues showed no immunoreactivity in enzyme-linked immunosorbent assay.

The effect of yag laser iridotomy on the blood aqueous barrier in the rabbit

The effect of YAG laser iridotomy on the blood aqueous barrier in the rabbit was investigated in 21 eyes. In seven series, each containing three pigmented rabbits, the right eye received a YAG laser iridotomy in the upper nasal quadrant of the peripheral iris under standardized conditions utilizing the Mikroruptor II (Lasag Company, Thun/Switzerland). One of the parameters describing the blood aqueous barrier effects was the intraocular pressure, which was monitored at 10 min intervals. The iridotomy caused significant pressure increases in the treated eyes which was maintained up to 90 min following the laser procedure. The measurement of the protein concentration and the lactate dehydrogenase activity was done at equal time intervals after the iridotomy, on the basis of anterior chamber tapping of the treated eyes and the untreated control eyes. Over a period of 100 min after laser surgery, a positive correlation between time and protein concentration for the treated eyes (r = + 0.86) could be established. The activity of the enzyme lactate dehydrogenase in the treated eyes was increased within 5 min of the trauma, reaching a maximum 45 min after surgery, and the increase in activity level remained 150 min after surgery. The results indicate that the disturbance of the blood aqueous barrier with the YAG laser is not essentially different from that of the argon laser, although tissue damage may be more pronounced.