Supply of care by dental therapists and emergency dental consultations in Alaska native communities in the Yukon-Kuskokwim delta: a mixed methods evaluation.

OBJECTIVES: Examine the relationship between supply of care provided by dental therapists and emergency dental consultations in Alaska Native communities. METHODS: Explanatory sequential mixed-methods study using Alaska Medicaid and electronic health record (EHR) data from the Yukon-Kuskokwim Health Corporation (YKHC), and interview data from six Alaska Native communities. From the Medicaid data, we estimated community-level dental therapy treatment days and from the EHR data we identified emergency dental consultations. We calculated Spearman partial correlation coefficients and ran confounder-adjusted models for children and adults. Interview data collected from YKHC providers (N=16) and community members (N=125) were content analysed. The quantitative and qualitative data were integrated through connecting. Results were visualized with a joint display. RESULTS: There were significant negative correlations between dental therapy treatment days and emergency dental consultations for children (partial rank correlation = -0.48; p⟨0.001) and for adults (partial rank correlation = -0.18; p=0.03). Six pediatric themes emerged: child-focused health priorities; school-based dental programs; oral health education and preventive behaviors; dental care availability; healthier teeth; and satisfaction with care. There were four adult themes: satisfaction with care; adults as a lower priority; difficulties getting appointments; and limited scope of practice of dental therapy. CONCLUSIONS: Alaska Native children, and to a lesser extent adults, in communities served more intensively by dental therapists have benefitted. There are high levels of unmet dental need as evidenced by high emergency dental consultation rates. Future research should identify ways to address unmet dental needs, especially for adults.

Survey of infection control and antimicrobial stewardship practices in Australian residential aged-care facilities.

This study assessed infection prevention and antimicrobial stewardship (AMS) practices in Australian residential aged-care facilities (RACF). Two hundred and sixty-five surveys (15.6%) were completed with all states represented and the majority (177 (67.3%)) privately run. Only 30.6% RACF had infection control trained staff on site. Few facilities had AMS policies, only 14% had antimicrobial prescribing restrictions. Most facilities offered vaccination to residents (influenza vaccination rates >75% in 73% of facilities), but pneumococcal vaccination was poor.

Effect of weight loss on mortality in overweight and obese nursing home residents during a 5-year follow-up.

BACKGROUND/OBJECTIVES: The objective of this study was to ascertain the effect of weight loss over the course of 1 year on 5-year mortality in old nursing home (NH) residents in different classes of body mass index (BMI). SUBJECTS/METHODS: A longitudinal study was conducted on 161 NH residents aged ⩾ 70 years at the Istituto di Riposo per Anziani, Padova, Italy. Data were collected using a comprehensive geriatric assessment at baseline and at a 1-year follow-up visit. Mortality was recorded over a 5-year follow-up. We divided our sample into four groups using as cutoffs a BMI of 25 and a weight gain or loss of 5% at 1 year (BMI ⩾ 25 and weight stable/gain, BMI ⩾ 25 and weight loss, BMI<25 and weight stable/gain and BMI <25 and weight loss). RESULTS: People with a BMI ⩾ 25 and weight loss suffered the worst decline in activities of daily living, whereas those with a BMI <25 and weight loss had the most significant decline in nutritional status, which coincided with the worst decline in the Multidimensional Prognostic Index among the groups whose weight changed. Compared with those with a BMI ⩾ 25 and weight stable/gain (reference group), those with a BMI <25 were at the highest risk of dying (in association with weight loss: hazard ratio HR=3.60, P=0.005; in association with weight stable/gain: HR=2.45, P=0.01), and the mortality risk was also increased in people with a BMI ⩾ 25 and weight loss (HR=1.74, P=0.03). CONCLUSIONS: In conclusion, weight loss increases the mortality risk in frail, disabled NH residents, even if they are overweight or obese.

School-age children's safety attitudes, cognitions, knowledge, and injury experiences: how do these relate to their safety practices?

BACKGROUND: A variety of factors affect the safety and risk practices of school-age children, but rarely have multiple factors been considered simultaneously. OBJECTIVE: To examine children's safety attitudes and cognitions more thoroughly and assess how these factors, along with children's safety knowledge and injury experiences, relate to children's safety practices. METHODS: Over several classroom sessions, boys and girls in two age groups (7-9, 10-12 years) completed a psychometrically sound questionnaire that indexes their behaviors, attitudes, cognitions, knowledge, and injury experiences. RESULTS: Fewer safety practices were reported by older than younger children and boys than girls. Children's attitudes, cognitions, knowledge, and injury experiences each correlated with safety practices, but only safety attitudes and injury experiences predicted practices in a multivariate model. CONCLUSION: Exploring the relative influence of numerous factors on safety practices highlights the important role that attitudes play in predicting children's safety practices. Implications of these results for injury prevention programming are discussed.

Detection of naphthenic acids in fish exposed to commercial naphthenic acids and oil sands process-affected water.

Naphthenic acids are a complex mixture of carboxylic acids that occur naturally in petroleum. During the extraction of bitumen from the oil sands in northeastern Alberta, Canada, naphthenic acids are released into the aqueous phase and these acids become the most toxic components in the process-affected water. Although previous studies have exposed fish to naphthenic acids or oil sands process-affected waters, there has been no analytical method to specifically detect naphthenic acids in fish. Here, we describe a qualitative method to specifically detect these acids. In 96-h static renewal tests, rainbow trout (Oncorhynchus mykiss) fingerlings were exposed to three different treatments: (1) fed pellets that contained commercial naphthenic acids (1.5mg g(-1) of food), (2) kept in tap water that contained commercial naphthenic acids (3mg l(-1)) and (3) kept in an oil sands process-affected water that contained 15mg naphthenic acids l(-1). Five-gram samples of fish were homogenized and extracted, then the mixture of free fatty acids and naphthenic acids was isolated from the extract using strong anion exchange chromatography. The mixture was derivatized and analyzed by gas chromatography-mass spectrometry. Reconstructed ion chromatograms (m/z=267) selectively detected naphthenic acids. These acids were present in each fish that was exposed to naphthenic acids, but absent in fish that were not exposed to naphthenic acids. The minimum detectable concentration was about 1microg naphthenic acids g(-1) of fish.

An unusual beta-ketoacyl:acyl carrier protein synthase and acyltransferase motifs in TaK, a putative protein required for biosynthesis of the antibiotic TA in Myxococcus xanthus.

The antibiotic TA of Myxococcus xanthus is produced by a type-I polyketide synthase mechanism. Previous studies have indicated that TA genes are clustered within a 36-kb region. The chemical structure of TA indicates the need for several post-modification steps, which are introduced to form the final bioactive molecule. These include three C-methylations, an O-methylation and a specific hydroxylation. In this study, we describe the genetic analysis of taK, encoding a specific polyketide beta-ketoacyl:acyl carrier protein synthase, which contains an unusual beta-ketoacyl synthase and acyltransferase motifs and is likely to be involved in antibiotic TA post-modification. Functional analysis of this beta-ketoacyl:acyl carrier protein synthase by specific gene disruption suggests that it is essential for the production of an active TA molecule.

Penetration of the coral-bleaching bacterium Vibrio shiloi into Oculina patagonica.

Inoculation of the coral-bleaching bacterium Vibrio shiloi into seawater containing its host Oculina patagonica led to adhesion of the bacteria to the coral surface via a beta-D-galactose receptor, followed by penetration of the bacteria into the coral tissue. The internalized V. shiloi cells were observed inside the exodermal layer of the coral by electron microscopy and fluorescence microscopy using specific anti-V. shiloi antibodies to stain the intracellular bacteria. At 29 degrees C, 80% of the bacteria bound to the coral within 8 h. Penetration, measured by the viable count (gentamicin invasion assay) inside the coral tissue, was 5.6, 20.9, and 21.7% of the initial inoculum at 8, 12, and 24 h, respectively. The viable count in the coral tissue decreased to 5.3% at 48 h, and none could be detected at 72 h. Determination of V. shiloi total counts (using the anti-V. shiloi antibodies) in the coral tissue showed results similar to viable counts for the first 12 h of infection. After 12 h, however, the total count more than doubled from 12 to 24 h and continued to rise, reaching a value 6 times that of the initial inoculum at 72 h. Thus, the intracellular V. shiloi organisms were transformed into a form that could multiply inside the coral tissue but did not form colonies on agar medium. Internalization of the bacteria was accompanied by the production of high concentrations of V. shiloi toxin P activity in the coral tissue. Internalization and multiplication of V. shiloi are discussed in terms of the mechanism of bacterial bleaching of corals.

A nonessential signal peptidase II (Lsp) of Myxococcus xanthus might be involved in biosynthesis of the polyketide antibiotic TA.

Myxococcus xanthus is a gram-negative soil bacterium that produces the polyketide antibiotic TA. In this study, we describe the analysis of an M. xanthus gene which encodes a homologue of the prolipoprotein signal peptidase II (SPase II; lsp). Overexpression of the M. xanthus SPase II in Escherichia coli confers high levels of globomycin resistance, confirming its function as an SPase II. The M. xanthus gene encoding the lsp homologue is nonessential for growth, as determined by specific gene disruption. It has been mapped to the antibiotic TA gene cluster, and the disrupted mutants do not produce the antibiotic, indicating a probable involvement in TA production. These results suggest the existence of more than one SPase II protein in M. xanthus, where one is a system-specific SPase II (for TA biosynthesis).

Aromatic and basic residues within the EVH1 domain of VASP specify its interaction with proline-rich ligands.

Short contiguous peptides harboring proline-rich motifs are frequently involved in protein-protein interactions, such as associations with Src homology 3 (SH3) and WW domains. Although patches of aromatic residues present in either domain interact with polyprolines, their overall structures are distinct, suggesting that additional protein families exist that use stacked aromatic amino acids (AA domains) to bind polyproline motifs [1] [2] [3]. A polyproline motif (E/DFPPPPTD/E in the single-letter amino-acid code), present in the ActA protein of the intracellular bacterial pathogen Listeria monocytogenes, serves as a ligand for the Ena/VASP protein family --the vasodilator-stimulated phosphoprotein (VASP), the murine protein Mena, Drosophila Enabled (Ena) and the Ena/VASP-like protein Evl [4] [5] [6] [7]. These share a similar overall structure characterized by the two highly conserved Ena/VASP homology domains (EVH1 and EVH2) [5]. Here, using three independent assays, we have delineated the minimal EVH1 domain. Mutations of aromatic and basic residues within two conserved hydrophilic regions of the EVH1 domain abolished binding to ActA. Binding of an EVH1 mutant with reversed charges could partially be rescued by introducing complementary mutations within the ligand. Like SH3 domains, aromatic residues within the EVH1 domain interacted with polyprolines, whereas the ligand specificity of either domain was determined by reciprocally charged residues. The EVH1 domain is therefore a new addition to the AA domain superfamily, which includes SH3 and WW domains.

Mutations in the Saccharomyces cerevisiae gene SAC1 cause multiple drug sensitivity.

Wild-type yeast Saccharomyces cerevisiae are surprisingly resistant to a wide range of drugs and agents. We had previously isolated novobiocin-sensitive mutants to aid the study of the intracellular target for this drug. Characterization of one of these mutants, mds1, revealed that it was sensitive not only to novobiocin but also to a wide range of drugs. The nature of this multiple drug-sensitive phenotype was shown to be different from that of previously isolated multiple drug-sensitive mutants. We have shown that the multiple drug-sensitivity of mds1 is due to mutations within the gene SAC1 and have identified a variety of mutations within the gene from the Mds1 strain. SAC1 encodes a protein which has been previously implicated in the correct function of the actin cytoskeleton, in inositol metabolism, in ATP transport in the endoplasmic reticulum and in Sec14p (PI-TP) function. We have shown that multiple drug-sensitivity is a new phenotype seen in some, but not all, of the previously characterized sac1 mutants. Based on our findings, we propose a mechanism by which Sac1p could affect drug resistance and also mediate other effects on cell growth.

Paucity of retinoic acid receptor alpha (RAR alpha) nuclear immunostaining in gliomas and inability of retinoic acid to influence neural cell adhesion molecule (NCAM) expression.

Neural cell adhesion molecule (NCAM) is down-regulated during periods of embryological cell migration and may be important in local tumor migration or metastases. Conflicting information exists in the literature about NCAM expression in human glial tumors and little is known about its expression in human brain metastases. We immunohistochemically stained a panel of 43 primary human brain tumors and their cultured counterparts for NCAM including glioblastoma multiformes, anaplastic astrocytomas, oligodendrogliomas, and contrasted their staining with a panel of 3 meningiomas, 11 brain metastases, and 5 normal brain samples utilizing the monoclonal antibody NKH-1. Most gliomas and metastatic melanomas and lung carcinomas showed a high percentage of cells positive for NCAM expression while NCAM staining was negative for other carcinomas. No difference was seen between intensity or percentage of cells that were NCAM positive, based on tumor grade or type. In glioma cell lines, NCAM expression was lost upon passage. In 15 glioma cell lines we also determined NCAM isoform expression by reverse transcription/polymerase chain reaction (RT/PCR) and found that 6 of 15 had message for NCAM 180, 8 of 15 for NCAM 140, and only 3 of 15 had message for NCAM 120. Normal brains always contained message for the 180 isoform and usually had mRNA for all 3 isoforms. Using monoclonal antibodies for retinoic acid receptor alpha (RAR alpha), we found nuclear staining in melanomas and lung carcinomas metastatic to brain and only rarely in gliomas. Neither the relative antigen density of NCAM nor the percent of NCAM-positive cells appreciably changed upon incubation with retinoic acid (RA), as measured by flow cytometry. RAR alpha was not found at a level measurable by immunohistochemistry in nuclei of most glial tumors, providing an explanation for why RA might not induce NCAM expression. Whether paucity of RAR alpha on primary gliomas might also correlate with results from clinical trials showing limited efficacy of RA in treatment of human gliomas awaits further study.

Cloning and characterization of a Myxococcus xanthus cytochrome P-450 hydroxylase required for biosynthesis of the polyketide antibiotic TA.

The antibiotic TA, a complex macrocyclic polyketide of Myxococcus xanthus, is produced, like many other polyketides, through successive condensations of acetate by a type I polyketide synthase (PKS) mechanism. The chemical structure of this antibiotic and the mechanism by which it is synthesized indicate the need for several post-modification steps, such as a specific hydroxylation at C-20. Previous studies have shown that several genes, essential for TA biosynthesis, are clustered in a region of at least 36kb, which was subsequently cloned and analyzed. In this study, we report the analysis of a DNA fragment, containing a specific cytochrome P-450 hydroxylase, presumably responsible for the sole non-PKS hydroxylation at position C-20. Functional analysis of the cytochrome P-450 hydroxylase gene through specific gene disruption confirms that it is essential for the production of an active TA molecule.

The first gene in the biosynthesis of the polyketide antibiotic TA of Myxococcus xanthus codes for a unique PKS module coupled to a peptide synthetase.

The polyketide antibiotic TA is synthesized by the Gram negative bacterium Myxococcus xanthus in a multi-step process in which a unique glycine-derived molecule is used as a starter unit and elongated through the condensation of 11 acetate molecules by polyketide synthases (PKSs). Analysis of a 7.2 kb DNA fragment, encoding the protein that carries out the first condensation step, revealed that the fragment constitutes a single open reading frame, referred to as Ta1, which lacks the 5' and 3' ends and displays two regions of similarity to other proteins. The first 1020 amino acid residues at the N terminus of the polypeptide are similar to sequences of the large family of enzymes encoding peptide synthetases. They are followed by a second region displaying a high degree of similarity to type I PKS genes. The genetic analysis of this open reading frame is compatible with the proposed chemical structure of TA. The data indicate that the genes encoding TA have a modular gene organization, typical of a type I PKS system. The unusual feature of Ta1 is that the first PKS module of TA resides on the same polypeptide as the peptide synthetase functional unit.

A NusG-like transcription anti-terminator is involved in the biosynthesis of the polyketide antibiotic TA of Myxococcus xanthus.

The antibiotic TA of Myxococcus xanthus is synthesized through a type I polyketide synthase mechanism. Previous studies have indicated that several genes essential for TA production are clustered within a 40-kb region and are transcriptionally co-regulated. In this study, we report the genetic analysis of the first gene in the TA gene cluster, identified as a NusG-like transcription anti-terminator. Functional analysis of this NusG-like anti-terminator gene by specific gene disruption confirms that it is essential for TA production but not for normal growth and development.

Overexpression of a transmembrane isoform of neural cell adhesion molecule alters the invasiveness of rat CNS-1 glioma.

CNS-1 is a highly invasive neural cell adhesion molecule (NCAM)-positive rat glioma that exhibits similarities in its pattern of infiltration to human gliomas. To investigate whether increasing NCAM expression alters invasive behavior, retroviruses encoding human NCAM 140 and a cytoplasmic truncation of NCAM 140 were used to transduce a population of CNS-1 glioma cells that had a relatively low endogenous level of NCAM. Compared to cells transduced with a control virus, cells overexpressing either intact or truncated human NCAM 140 showed decreased invasion of a reconstituted basal lamina. Changes in growth rate or in key matrix metalloproteinase activities could not account for this result. In a migration assay on type IV collagen, cells exhibited a substrate concentration-dependent increase in the rate of migration; however, overexpression of NCAM 140 or truncated NCAM 140 inhibited motility at higher substrate concentrations. Consistent with these findings was the decreased spread of NCAM 140 overexpressers in vivo following instillation of cells into the right frontal cortex of rat brain. NCAM 140 overexpressers showed considerably more restricted perivascular and periventricular spread than cells transduced with a control virus. However, NCAM-140-overexpressing tumor exhibited a less cohesive pattern of growth near the site of tumor instillation and more individual cell infiltration of brain parenchyma with more pronounced perineuronal satellitosis. The stability of recombinant NCAM expression was confirmed by recovering tumor cells from tumor-bearing animals and measuring NCAM levels by flow cytometry. These observations show that overexpression of NCAM 140 decreases the long-range spread of CNS-1 glioma along basal lamina pathways but enhances local infiltration of neuropil.

Hypothesis: a possible role for mast cells and their inflammatory mediators in the pathogenesis of autoimmune encephalomyelitis.

Mast cells and their potent chemical mediators are known to initiate and modulate a number of important inflammatory cascades. With respect to the central nervous system, the role of mast cells as participants in the promotion and resolution of inflammation has been widely underestimated. Mast cell-derived histamine, serotonin, kallikreins, and tumor necrosis factor-alpha (TNF-alpha) can enhance microvascular permeability, leukocyte rolling, adhesion, and extravasation of inflammatory cells into the brain and spinal cord. Mast cell mediators may play an important role in autoimmune encephalomyelitis and multiple sclerosis by promoting the entry of autoreactive T cells and the recruitment of nonspecific monocytes across the blood:brain barrier.

Mast cell-derived histamine and tumour necrosis factor: differences between SJL/J and BALB/c inbred strains of mice.

Mast cells cultured from bone marrow of BALB/c and SJL/J inbred strains of mice using IL-3 showed distinct patterns of growth and marked differences in their content of TNF-alpha and histamine. Mast cells derived from SJL/J mice grew and matured at a faster rate than those from BALB/c bone marrow. SJL/J mast cells were found to contain more than twice the amount of histamine and TNF-alpha in their granules than BALB/c-derived cells. In addition, when triggered by anti-DNP IgE antibody and specific antigen (DNP-albumin), mast cells derived from SJL/J mice released more histamine and TNF-alpha than mast cells derived from BALB/c mice. These results confirm previous observations regarding a genetic basis for mouse strain differences in mast cell growth rates, and extend previous observations to document differences in mast cell mediator contents. These results are consistent with the concept that genetically controlled differences in the numbers of central nervous system (CNS)-associated mast cells and their vasogenic mediators may play an important role in modulating oedema and inflammation in CNS trauma and diseases in mice.

Molecular analysis of the Drosophila catalase gene.

The main objective of this study was to isolate and characterize the catalase gene and accompanying cis-regulatory regions in Drosophila melanogaster. Genomic clones were obtained on the basis of cross-hybridization to catalase cDNA and a 7-kb SalI-KpnI fragment encompassing the catalase gene was introduced into Drosophila by P element-mediated transformation. A single transgene, when placed in a catalase null background, was sufficient to restore resistance to H2O2 as well as reduce susceptibility to early death. DNA sequence of the catalase gene domain was obtained. This included 1365 bp of sequence upstream of the transcription initiation site and 1423 bp downstream of the termination codon. The Drosophila catalase gene is composed of 3 exons, encoding 19, 307, and 180 amino acids, which are separated by 3520- and 96-bp introns. Sequence analysis of the promoter domain is presented, revealing multiple sequence similarities between catalase and Cu,Zn superoxide dismutase promoter domains. Developmental RNA get analysis shows that peaks of catalase mRNA accumulation correspond roughly with major peaks of ecdysone titer during third instar and pupal stages. Candidate ecdysone response element sequences are noted downstream of the catalase polyadenylation site.