Dental plaque pH and ureolytic activity in children and adults of a low caries population.

OBJECTIVES: The aim of this study was to evaluate the plaque pH level and ureolytic activity among children and adults of Karen Hill tribes. METHODS: Thirty-four children aged 6-10 years and 46 adults aged 20-38 years were interviewed regarding oral hygiene practices, sucrose intake and betel chewing. Caries experience (DMFT and DT), calculus, bleeding on probing (BoP) and Plaque index (PlI) were registered. Ureolytic activity in supragingival plaque was tested at two interproximal sites (11/12 and 41/42) with the rapid urease test (RUT). Registration of plaque pH was performed at two interproximal sites (15/16 and 31/41) before, during and 30 min after rinsing with an urea solution (0.25%). Four interproximal plaque samples (one from each quadrant) per individual were collected to test the bacterial composition using the checkerboard technique. RESULTS: Children and adults had similarly low DMFT and DT values. Children had a higher baseline pH and a higher ureolytic activity in the maxilla (p < 0.05) compared with adults. A significant correlation (r (2) = 0.63) was found between baseline pH and urease activity in the mandibular anterior teeth. Caries-free individuals had a higher baseline pH compared with caries active individuals in the anterior mandibular region (p < 0.01). The microbiological composition was characterized by an anaerobic low acidiogenic microbiota. CONCLUSIONS: Dental plaque pH is related to the ureolytic activity, which explains the low acidogenic plaque microflora and the low caries levels in the Karen population.

Depressive Symptoms Are Not Associated with Predementia Cerebrospinal Fluid Amyloid Pathology.

Introduction: Depressive symptoms are associated with Alzheimer's disease (AD), but their neurobiological and neuropsychological correlates remain poorly understood. We investigate if depressive symptoms are associated with amyloid (Aß) pathology and cognition in predementia AD. Methods: We included subjective cognitive decline (SCD, n = 160) and mild cognitive impairment (MCI, n = 192) from the dementia disease initiation cohort. Depressive symptoms were assessed using the Geriatric Depression Scale (GDS-15). Aß pathology was determined using cerebrospinal fluid (CSF) Aß42/40 ratio. Associations between depressive symptoms and cognition were assessed with logistic regression. Results: Only the Aß negative MCI group (MCI-Aß-) was associated with depressive symptoms (odds ratio [OR] = 2.65, p = 0.005). Depressive symptoms were associated with worse memory in MCI-Aß- (OR = 0.94, p = 0.039), but with better performance in MCI-Aß+ (OR = 1.103, p = 0.001). Conclusion: Our results suggest that depressive symptoms in MCI are neither associated with Aß pathology, nor AD-associated memory impairment. However, memory impairment in non-AD MCI may relate to depressive symptoms.

Cerebrospinal fluid markers for synaptic function and Alzheimer type changes in late life depression.

To explore markers for synaptic function and Alzheimer disease (AD) pathology in late life depression (LLD), predementia AD and normal controls (NC). A cross-sectional study to compare cerebrospinal fluid (CSF) levels of neurogranin (Ng), Beta-site amyloid-precursor-protein cleaving enzyme1 (BACE1), Ng/BACE1 ratio and Amyloid-ß 42/40 ratio, phosphorylated-tau and total-tau in LLD with (LLD AD) or without (LLD NoAD) AD pathology, predementia AD and normal controls (NC). We included 145 participants (NC = 41; predementia AD = 66 and LLD = 38). LLD comprised LLD AD (n = 16), LLD NoAD (n = 19), LLD with non-AD typical changes (n = 3, excluded). LLD AD (pADJ < 0.05) and predementia AD (pADJ < 0.0001) showed significantly higher Ng than NC. BACE1 and Ng/BACE1 ratio were altered similarly. Compared to LLD NoAD, LLD AD showed significantly higher Ng (pADJ < 0.001), BACE1 (pADJ < 0.05) and Ng/BACE1 ratio (pADJ < 0.01). All groups had significantly lower Aß 42/40 ratio than NC (predementia AD and LLD AD, p < 0.0001; LLD NoAD, p < 0.05). Both LLD groups performed similarly on tests of memory and executive function, but significantly poorer than NC. Synaptic function in LLD depended on AD pathology. LLD showed an association to Amyloid dysmetabolism. The LLD groups performed poorer cognitively than NC. LLD AD may be conceptualized as "predementia AD with depression".

Affibody molecule-mediated depletion of HSA and IgG using different buffer compositions: a 15 min protocol for parallel processing of 1-48 samples.

High-abundant plasma proteins pose a challenge in a large number of proteomics-based technologies. Depletion of these high-abundant proteins has proven to be a fruitful strategy to circumvent masking of lower-abundant proteins that could serve as valuable biomarker candidates. However, current strategies often do not meet the throughput requirements of large-scale proteomic studies. In the present paper, a flexible and parallelized method for the depletion of high-abundant proteins is described, allowing the removal of the two most abundant proteins from 48 blood-derived samples in less than 15 min using Affibody molecules as affinity ligands. A sample-processing platform like this should be suitable for a number of proteomics technologies; its flexibility in buffer composition allows for different types of downstream applications.

Amyloid Plaques and Symptoms of Depression Links to Medical Help-Seeking due to Subjective Cognitive Decline.

BACKGROUND: Subjective cognitive decline (SCD) is associated with an increased risk of Alzheimer's disease (AD). However, patients reporting SCD to their general practitioner are not always referred to a memory clinic. OBJECTIVE: To investigate whether prior history of medical help-seeking is associated with AD biomarker abnormality, worse cognitive performance, and/or depressive symptoms in SCD. METHODS: We compared levels of cerebrospinal fluid (CSF) Aß1 - 42, cognitive performance, and depressive symptoms (15-item Geriatric Depression Scale, GDS-15) between healthy controls (n = 88), SCD with a history of medical help seeking (SCD-HS, n = 67), and SCD non help-seekers (SCD-NHS, n = 44). Cases with evidence of amyloid plaques (CSF Aß1 - 42 ≤708 ng/l) and symptoms of depression (GDS-15≥6) were determined in both SCD groups. RESULTS: The SCD-HS group had lower CSF Aß1 - 42 (p < 0.01), lower word list learning and memory recall (p < 0.0001), and an increased level of depressive symptoms (p < 0.0001) compared to controls and SCD-NHS cases. The SCD-HS group had more cases with symptoms of depression (n = 12, 18%) and amyloid plaques (n = 18, 27%) compared to SCD-NHS (n = 1, 2% and n = 7, 16%, respectively). None of the SCD-HS cases and only one SCD-NHS case had concurrent symptoms of depression and amyloid plaques. The SCD-HS cases showed equal word list learning and memory performance regardless of amyloid status or symptoms of depression. CONCLUSION: Medical help-seeking in SCD is associated with an increased risk of AD pathology or symptoms of depression. However, subtle memory deficits are seen in SCD help-seekers, also without amyloid plaques or symptoms of depression.

In Brief Neuropsychological Assessment, Amnestic Mild Cognitive Impairment (MCI) Is associated with Cerebrospinal Fluid Biomarkers for Cognitive Decline in Contrast to the Prevailing NIA-AA MCI Criterion.

BACKGROUND: In the care of persons with cognitive problems, it is important to use a valid mild cognitive impairment (MCI) criterion that discriminates well between normal and pathological aging. OBJECTIVE: To find the brief neuropsychological screening criterion that best correlates with cerebrospinal fluid (CSF) biomarkers for cognitive decline and dementia in persons seeking help for cognitive problems. METHODS: 452 consecutively recruited patients (age 40-80 years) from memory-clinics in the Norwegian national multicentre longitudinal study Dementia Disease Initiation were included. CSF data as well as full data from brief neuropsychological screening were available for all patients. RESULTS: Amnestic MCI, including at least one memory test below T-score 40, outperformed the conventional US National Institute on Aging-Alzheimer's Association (NIA-AA) MCI criterion. Only amnestic MCI was significantly associated with biomarker pattern of NIA-AA stage 2 (low CSF Aß42 concentrations and elevated tau) in multivariate regression analysis. CONCLUSIONS: The finding that amnestic MCI based on brief neuropsychological assessment is significantly associated with CSF biomarkers for cognitive decline and Alzheimer's disease is in accordance with longitudinal studies that find memory impairment; both in itself and especially in combination with other cognitive deficit to constitute a risk factor for subsequent cognitive decline and dementia. The prevalence of pathological biomarkers for Alzheimer's disease is common in the elderly and the clinical significance of present findings depend on longitudinal validation.

Callus formation and remodeling at titanium implants.

Titanium is biocompatible with bone tissue, and during the healing process bone makes intimate contact with the implant surface. Although much is known about the long-term healing of implants, less is known about the callus formation at implants. In this study, the histology of bone healing was studied during the period between 4 and 14 days. Incisions were made in rat tibia. Some incisions were simply left to heal, while in others titanium discs were implanted. Smooth implants as well as implants with different porosities were used. After 4, 7, and 14 days of healing, the sites of bone incisions were retrieved, decalcified, sectioned, and stained. The aim was to compare normal fracture healing with implant healing and to see whether implant properties influenced the short-term healing process. Similarities between fracture healing and implant healing were evident. In both cases, inflammation, soft and hard callus formation, and remodeling had taken place during the period investigated. Between 7 and 14 days substantial bone resorption occurred around the implants. While after 14 days the marrow was almost completely reconstituted during normal wound healing, at the implants a thin layer of bone remained in close contact with the surface. Results from bone-implant contact measurements indicate that the surface properties of the implants do not have a significant influence on the early bone formation, since there were no significant differences between the smooth surface and any of the porous surfaces.

A well-being programme in severe mental illness. Reducing risk for physical ill-health: a post-programme service evaluation at 2 years.

INTRODUCTION: Cardiovascular disease is more prevalent in patients with severe mental illness (SMI) than in the general population. METHOD: Seven geographically diverse centres were assigned a nurse to monitor the physical health of SMI patients in secondary care over a 2-year period in the "Well-being Support Programme" (WSP). A physical health screen was performed and patients were given individual weight and lifestyle advice including smoking cessation to reduce cardiovascular risk. RESULTS: Nine hundred and sixty-six outpatients with SMI >2 years were enrolled. The completion rate at 2 years was 80%. Significant improvements were observed in levels of physical activity (p<0.0001), smoking (p<0.05) and diet (p<0.0001). There were no changes in mean BMI although 42% lost weight over 2 years. Self-esteem improved significantly. Low self-esteem decreased from 43% at baseline to 15% at 2 years (p<0.0001). At the end of the programme significant cardiovascular risk factors remained, 46% of subjects smoked, 26% had hypertension and 81% had BMI >25. CONCLUSION: Physical health problems are common in SMI subjects. Many patients completed 2 years follow up suggesting that this format of programme is an acceptable option for SMI patients. Cardiovascular risk factors were significantly improved. Interventions such as the Well-being Support Programme should be made widely available to people with SMI.

Implantation of hydrophilic and hydrophobic titanium discs in rat tibia: cellular reactions on the surfaces during the first 3 weeks in bone.

In a previous study, a method for evaluation of short-time (1-8 days) healing of titanium implants in rat tibiae was described (J. Biomed. Mater. Res. 66A(3) (2003) 662). The implants were disc-shaped and cells and tissue on the surface were investigated, not the adjacent tissue. In this study healing during the first 3 weeks in bone was examined and the healing response between hydrophilic and hydrophobic titanium was compared. Immunofluorescence techniques were used to detect signs of bone formation on the surfaces. Cell viability, alkaline phosphatase (ALP) activity, presence of osteocalcin and cells positive for bone morphogenetic protein-2 (BMP-2) and vascular endothelial growth factor (VEGF) were investigated. Both viable and non-viable cells were found on both surfaces during the first week. Only initially was there a difference between them; 4% viable cells on hydrophilic discs compared to 56% on hydrophobic ones. More BMP-2 positive cells were found on hydrophilic discs than on hydrophobic ones after 1 week. VEGF was detected after 8 days on both surfaces. Osteocalcin positive cells were found from 2 weeks. ALP positive cells were found after 8 days, while at 2-3 weeks ALP positive tissue was abundant on both surfaces. In conclusion, signs of bone formation were detected during the period investigated. Surface energy appeared to be of more importance initially, with higher surface energy resulting in more rapid cell activation and differentiation than lower.

Thrombin, kallikrein and complement C5b-9 adsorption on hydrophilic and hydrophobic titanium and glass after short time exposure to whole blood.

Hydrophilic and hydrophobic titanium and glass were exposed to capillary whole blood between 5s and 24h. The time-sequence for adsorption of thrombin, kallikrein and complement C5b-9, and their relationship with adherent platelets and polymorphonuclear granulocyte (PMN) activation were investigated. Adsorbed thrombin and kallikrein were measured by cleavage of specific chromogenic substances, S-2238 and S-2303, respectively. Complement C5b-9 and expression of CD11b, CD66b, CD62P and Pan-platelets were measured by immunofluorescence. Thrombin and kallikrein were present on the surfaces during the whole investigated periods. Platelet adhesion and PMN cell adhesion and activation on all surfaces and activation of platelets on hydrophobic surfaces showed a similar pattern to thrombin adsorption. Kallikrein adsorption had a different pattern on each surface. C5b-9 was detected between 32min and 24h of blood exposure and a varying pattern of C5b-9 coverage was observed on each surface. In conclusion, our results indicate that the interaction between material and blood coagulation and kinin-activating proteins regulate the adhesion and activation of blood cells, whereas after longer time the coagulation and kallikrein-kinin system play minor roles and the complement system is decisive for mediating and elongating the inflammatory process.

Novel in vivo method for evaluation of healing around implants in bone.

A material implanted in bone is always inserted into coagulating blood. Protein and cell interactions during this initial implantation time will govern later healing. Many studies have focused on the tissue surrounding implants. We have developed a method for evaluation of healing around implants in bone by studying cells adhering to the implant surface. Hydrophilic titanium discs were inserted into rat tibiae. Samples were retrieved after 1, 2, 4, and 8 days of implantation and were analyzed by fluorescence microscopy techniques and scanning electron microscopy. Both proliferating and apoptotic cells were found on the surface. Generally, cells closest to the implant surface were nonviable whereas cells in the fibrin network a distance from the surface were viable. Bone morphogenetic protein-2 (BMP-2) is an osteogenic substance. An increase in BMP-2-positive cells was seen during the implantation period, and a population of large BMP-2-positive cells appeared on the surface after 4 days of implantation. The method developed here is a suitable tool for rapid evaluation of the initial healing around implant material.

Origins and biological accumulation of small plastic particles in fur seals from Macquarie Island.

One hundred and sixty four plastic particles (mean length 4.1 mm) recovered from the scats of fur seals (Arctocephalus spp.) on Macquarie Island were examined. Electron micrographs of 41 of the plastic particles showed that none could be identified as plastic pellet feedstock from their shapes. Commonly, such pellets are cylindrical and spherical. Instead, all the 164 plastic particles from the seal scats were angular particles of 7 colors (feedstock particles are normally opaque or white) and could be classified into 2 categories: i) fragmented along crystal lines and likely to be the result of UV breakdown; and ii) worn by abrasion (where striations were clearly visible) into irregular shapes with rounded corners. White, brown, green, yellow and blue were the most common colors. In composition, they came from 5 polymer groups; polyethylene 93%, polypropylene 4%, poly(1-Cl-1-butenylene) polychloroprene 2%, melamine-urea (phenol) (formaldehyde) resin 0.5%, and cellulose (rope fiber) 0.5%. The larger groups are buoyant with a specific gravity less than that of seawater. These small plastic particles are formed from the breakdown of larger particles (fragments). Their origin seems to be from the breakdown of user plastics washed ashore and ground down on cobbled beaches. Certainly most particles (70%) had attained their final form by active abrasion. It is hypothesized that the plastic particles were washed out to sea and then selected by size and consumed by individuals of a pelagic fish species, Electrona subaspera, who in turn were consumed by the fur seals. Thus, the particles were accumulated both by the fish and the seals in the usual process of their feeding.

MALDI Imaging Mass Spectrometry-A Mini Review of Methods and Recent Developments.

As the only imaging method available, Imaging Mass Spectrometry (IMS) can determine both the identity and the distribution of hundreds of molecules on tissue sections, all in one single run. IMS is becoming an established research technology, and due to recent technical and methodological improvements the interest in this technology is increasing steadily and within a wide range of scientific fields. Of the different IMS methods available, matrix-assisted laser desorption/ionization (MALDI) IMS is the most commonly employed. The course at IMSC 2012 in Kyoto covered the fundamental principles and techniques of MALDI-IMS, assuming no previous experience in IMS. This mini review summarizes the content of the one-day course and describes some of the most recent work performed within this research field.

Diverse pathological implications of YKL-40: answers may lie in 'outside-in' signaling.

The developing paradigms about YKL-40, a member of the "mammalian chitinase-like proteins", from across the globe, project it as a vital parameter for the detection of disease onset and progression. It is expressed and secreted by cancer cells of different origins along with a variety of non-malignant cells including inflammatory and structural cells. Numerous studies demonstrate that YKL-40 over-expression is associated with increased patient mortality though the cellular receptors responsible for mediating these effects have not yet been identified. The putative YKL-40 ligands are thought to be carbohydrate structures, since it is capable of binding chitin, chito-oligosaccharides and heparin. Binding of collagen to YKL-40, identified it as the only non-carbohydrate extracellular matrix (ECM) ligand for YKL-40. Our broad understanding of YKL-40 as a versatile biomarker and its involvement in activating several signaling pathways make us anticipate that its specific receptors/binding partners may exist on the cell surface also. The cell surface heparan sulfate (HS) moieties seem to be the potential candidates for this role, suggesting that it could interact with HS-proteoglycans. It is recommended to clearly delineate YKL-40-mediated signaling mechanisms before promoting the YKL-40 know-how for translational research, in both diagnostic and therapeutic applications. The present review provides an overview of YKL-40 as a versatile biomarker, discussing the related pathological mechanisms and aims to reassess and unify the already proposed diverse hypotheses in YKL-40-regulated signaling mechanisms.

Daily accumulation rates of marine debris on sub-Antarctic island beaches.

The worlds' oceans contain a large but unknown amount of plastic debris. We made daily collections of marine debris stranded at two sub-Antarctic islands to establish (a) physical causes of strandings, and (b) a sampling protocol to better estimate the oceans' plastic loading. Accumulation rates at some beaches were dependent on tide and onshore winds. Most of the 6389 items collected were plastic (Macquarie 95%, Heard 94%) and discarded or lost fishing gear comprised 22% of those plastic items. Stalked barnacles (Lepas spp.) were a regular attachment on Macquarie debris but not at Heard Island. The daily accumulation rate of plastic debris on Macquarie Island was an order of magnitude higher than that estimated from monthly surveys during the same 4 months in the previous 5 years. This finding suggests that estimates of the oceans' plastic loading are an order of magnitude too low.

Targeted protein pullout from human tissue samples using competitive elution.

One commonly used strategy to gain information on the proteins in a cell is to isolate the proteins of interest by specific binders, often antibodies. Not only the specificity of the capturing antibodies but also the washing and elution conditions are crucial to avoid false-positive protein identifications. Eluting the target protein from the matrix, while avoiding the release of unrelated background proteins, should both provide more correct information on the target protein and its interaction partners, and minimize the effort to perform downstream analyses through the reduced number of eluted proteins. In this study, a novel approach for selective protein pullout is presented. Monospecific antibodies were used to selectively pullout target proteins from a complex biosample. Subsequently, the target proteins were competitively eluted from the affinity media with the recombinant antigen. To deplete the antigen from the eluted sample, IMAC spin columns were utilized to bind the N-terminal His-tag of the antigens. The competitive elution method was applied both to a model system, and for the extraction of a native human target protein. In the model system the recombinant target protein BBC7 was spiked into a protein extract of human liver, whereas an endogenously expressed target protein, cTAGE5, was extracted from the liver extract directly. SDS-PAGE analysis and mass spectrometry confirmed affinity isolation of expected target proteins. More selective elution was obtained using the competitive procedure as compared to elution at low pH. Competitive elution has thus been shown to offer an effective approach for wide-scale pullout experiments where proteins and their interaction partners are to be studied.

Parallel production and verification of protein products using a novel high-throughput screening method.

Protein production and analysis in a parallel fashion is today applied in laboratories worldwide and there is a great need to improve the techniques and systems used for this purpose. In order to save time and money, a fast and reliable screening method for analysis of protein production and also verification of the protein product is desired. Here, a micro-scale protocol for the parallel production and screening of 96 proteins in plate format is described. Protein capture was achieved using immobilized metal affinity chromatography and the product was verified using matrix-assisted laser desorption ionization time-of-flight MS. In order to obtain sufficiently high cell densities and product yield in the small-volume cultivations, the EnBase® cultivation technology was applied, which enables cultivation in as small volumes as 150 µL. Here, the efficiency of the method is demonstrated by producing 96 human, recombinant proteins, both in micro-scale and using a standard full-scale protocol and comparing the results in regard to both protein identity and sample purity. The results obtained are highly comparable to those acquired through employing standard full-scale purification protocols, thus validating this method as a successful initial screening step before protein production at a larger scale.

Time-of-flight secondary ion mass spectrometric analysis of the interface between bone and titanium implants.

Implant healing into bone tissue is a process where the mature bone grows towards and eventually fuses with the implant. In this study we investigated implant healing during 4 weeks with focus on the implant-tissue interface. Our main interest was to study the mineralization process around the implant. Titanium discs were implanted in rat tibia for 2 and 4 weeks. After implantation cross sections of bone and implant were made using a low-speed saw equipped with a diamond wafering blade. One section from each sample was stained with basic fuchsin and micrographed by light microscopy (LM). The other section was analyzed with imaging time-of-flight secondary ion mass spectrometry (TOF-SIMS) using a Bi(3)(+) cluster ion source. This ion source has recently been shown to enable identification of high-mass hydroxyapatite (HA) fragment ions (m/z 291-653) in bone samples. The LM images were used to identify areas suitable for TOF-SIMS analysis. Three areas were selected for mass spectral analysis, corresponding to interface region, bone and soft tissue, from which positive ion spectra were recorded. In the areas identified as bone, high-mass HA fragments ions were found after both 2 and 4 weeks. In the soft tissue area, no high-mass ions were found after 4 weeks. However, after 2 weeks HA-related ions were identified in mineralized spots in areas defined as soft tissue. After 4 but not after 2 weeks, high-mass HA fragment ions were found in the interface region. In conclusion, differences were observed regarding mineralization between 2 and 4 weeks of implantation and between different regions surrounding the implants. Imaging TOF-SIMS analysis using a Bi(3)(+) cluster as ion source enables identification of high-mass HA fragment ions at implant-tissue interfaces in bone. This technique might therefore be useful for biocompatibility assessment and for studying the mineralization process at implant surfaces.

Analysis of bone minerals by time-of-flight secondary ion mass spectrometry: a comparative study using monoatomic and cluster ions sources.

Time-of-flight secondary ion mass spectrometry (TOF-SIMS) is an important tool for the analysis of bone minerals at implant surfaces. Most studies have been performed with monoatomic primary ion sources such as Ga(+) with poor secondary molecular ion production efficiency and only elemental distributions and minor fragments of bone minerals have been reported. By using cluster ion sources, such as Au(1-3) (+) and Bi(1-3) (+), identification of larger hydroxyapatite species at m/z 485, 541, 597 and 653, identified as Ca(5)P(3)O(12), Ca(6)P(3)O(13), Ca(7)P(3)O(14) and Ca(8)P(3)O(15), respectively, became possible. The ions appear to be fragments of the hydroxyapatite unit cell Ca(10)(PO(4))(6)(OH)(2). Each ion in the series is separated by 55.9 m/z units, corresponding to CaO, and this separation might reflect the columnar nature of the unit cell.