Social inequality in tooth loss: separate and joint effects of household income and dental visits.

OBJECTIVE: The aim of the study was to investigate the separate and joint effects of household income and dental visits on tooth loss. BASIC RESEARCH DESIGN: Participants from the Social Inequality in Cancer Cohort (SIC) were followed in registers for household income (2000), dental visits (2002-2009) and tooth loss (2010-2016). Logistic regression was used to assess the effect of household income and dental visits on tooth loss, and linear models were applied to assess the separate and joint effects of household income and dental visits. RESULTS: In total, 10.8% of the participants had tooth loss (⟨15 teeth present). Low household income and irregular dental visits showed significantly higher odds ratios for tooth loss. Compared to regular dental visits, irregular dental visits accounted for 923 (95% CI 840 - 1,005) extra cases of tooth loss per 10,000 persons, and compared to high household income, low household income accounted for 1,294 (95% CI 1,124 - 1,464) additional cases of tooth loss per 10,000 persons. Further, due to household income-dental visit interaction, we observed 581 (95% CI 233 - 928) extra cases of tooth loss per 10,000 persons. CONCLUSION: Low household income and irregular dental visits are important in relation to social inequality in tooth loss. Irregular dental visits are associated with higher risk of tooth loss among persons with low household income compared to persons with high household income. Such interaction may be explained by differences in susceptibility to tooth loss across household income groups.

Factors influencing GPs' perception of specialised palliative homecare (SPHC) importance - results of a cross-sectional study.

BACKGROUND: General Practitioners (GPs) are the main providers of primary palliative care (PPC). At the same time they are the main initiators of specialised palliative homecare (SPHC). In Germany, little is known about factors which influence GPs in their involvement of SPHC. Aim of our study is to identify factors that drive GPs to give value to and involve SPHC. METHODS: A cross-sectional survey was performed. In 2018, questionnaires were mailed to 6000 randomly selected GPs from eight German federal states, focusing on the extent of GPs' palliative care activities and their involvement of SPHC. RESULTS: With a response rate of 19.4% and exclusion of GPs working in SPHC-teams, n = 1026 questionnaires were appropriate for analysis. GPs valued SPHC support as the most "important/very important" for both "technical/invasive treatment measures" (95%) and availability outside practice opening hours (92%). The most relevant factor influencing perceived SPHC-importance was GPs' self-reported extent of engagement in palliative care (ß = - 0.283; CI 95% = - 0.384;-0.182), followed by the perceived quality of utilised SPHC (ß = 0.119; CI 95% = 0.048;0.190), involvement in treatment of palliative patients after SPHC initiation (ß = 0.088; CI 95% = 0.042;0.134), and conviction that palliative care should be a central part of GPs' work (ß = - 0.062; CI 95% = - 0.116;-0.008). Perceived SPHC-importance is also associated with SPHC-referrals (ß =0.138; p < 0.001). The lower the engagement of GPs in palliative care, the more they involve SPHC and vice versa. CONCLUSIONS: GPs with low reported activity in palliative care are more likely to initialise SPHC for palliative care activities they do not deliver themselves for various reasons, which might mean that the involvement of SPHC is substitutive instead of complementary to primary palliative care. This finding and its interpretation should be given more attention in the future policy framework for (specialised) palliative homecare. TRIAL REGISTRATION: German Clinical Trials Register DRKS00014726 , 14.05.2018.

Work assignments, delegation of tasks and job satisfaction among Danish dental hygienists.

INTRODUCTION: Recent legislation in Denmark has made it possible for dentists to delegate their tasks to dental hygienists. Previous studies have shown that Danish dental hygienists primarily were performing assignments within their own work field. These assignments include prophylaxis or instructing patients in oral health care. However, studies have also shown that Danish dental hygienists performed dental nurse assignments such as chair-side assistance, unit cleaning and disinfection of instruments. OBJECTIVES: The objectives of this study were to investigate (i) the range of work assignments performed by Danish dental hygienists, (ii) the types of dentist tasks performed by Danish dental hygienists and (iii) job satisfaction among Danish dental hygienists. DESIGN: Dental hygienists graduating in 2004-2007 were invited to participate in this study. METHODS: Participants answered an email-distributed questionnaire. The questionnaire consisted of questions regarding job satisfaction, assignments performed, postgraduate course attendance, receiving assistance from a dental nurse and which work assignments Danish dental hygienists wish to perform in the future. RESULTS: The results of this study showed that 90% of Danish dental hygienists were satisfied with their job and 52% were performing dentists' tasks. Among dentists' tasks performed by Danish dental hygienists, invasive caries therapy was the most frequently performed task. CONCLUSION: The type of assignments performed by Danish dental hygienists today appears to be changing compared to previous studies. From initially performing prophylaxis and chair-side assistance for the dentist, Danish dental hygienists today are performing a wider range of tasks which includes dentists' tasks.

The effect of alcohol consumption on periodontitis in older Danes.

OBJECTIVES: To examine the association of alcohol consumption measured at different points in time and periodontitis at 20 years follow-up and to investigate whether long-term alcohol consumption is related to periodontitis in old age. DESIGN: Participants aged 65 years or older in 2003, from the longitudinal study Copenhagen City Heart Study (CCHS), were invited to participate in the Copenhagen Oral Health Senior Study. METHODS: Clinical periodontal attachment loss was calculated to determine the progress of periodontitis. Alcohol consumption was measured at CCHS follow-ups in 1981-1983, 1991-1994 and 2001-2003, using a standard questionnaire. Alcohol consumption was defined as light, moderate and heavy drinking and used individually for each follow-up. The three follow-ups were summarized into long-term alcohol consumption. Logistic regression analysis was used to estimate the relation between alcohol consumption measured at different points in time and periodontitis and to assess the effect of long-term alcohol consumption on periodontitis. RESULTS: The results show that heavy drinkers in 1981-1983 had a higher odds ratio for having periodontitis compared to light drinkers (OR = 4.64 95% CI = [1.1; 19.42]). CONCLUSION: Early consumption of alcohol may increase the odds of having periodontitis 20 years later. There is a need for further studies including larger populations to investigate both alcohol consumption measured at different points in time, and long-term alcohol consumption and periodontitis progression over time.

Yield improvement of heterologous peptides expressed in yps1-disrupted Saccharomyces cerevisiae strains.

Heterologous protein expression levels in Saccharomyces cerevisiae fermentations are highly dependent on the susceptibility to endogenous yeast proteases. Small peptides, such as glucagon and glucagon-like-peptides (GLP-1 and GLP-2), featuring an open structure are particularly accessible for proteolytic degradation during fermentation. Therefore, homogeneous products cannot be obtained. The most sensitive residues are found at basic amino acid residues in the peptide sequence. These heterologous peptides are degraded mainly by the YPS1-encoded aspartic protease, yapsin1, when produced in the yeast. In this article, distinct degradation products were analyzed by HPLC and mass spectrometry, and high yield of the heterologous peptide production has been achieved by the disruption of the YPS1 gene (previously called YAP3). By this technique, high yield continuous fermentation of glucagon in S. cerevisiae is now possible.

The role of leaders in intracellular transport and secretion of the insulin precursor in the yeast Saccharomyces cerevisiae.

Pulse-chase analysis of folded and misfolded insulin precursor (IP) expressed in Saccharomyces cerevisiae was performed to establish the requirements for intracellular transport and the influence of the secretory pathway quality control mechanisms on secretion. Metabolic labelling of the IP expressed in S. cerevisiae showed that the effect of a leader was to stabilise the IP in the endoplasmic reticulum (ER), and facilitate intracellular transport of the fusion protein and rapid secretion. The first metabolically labelled IP appeared in the culture supernatant within 2-4 min of chase, and most of the secreted IP appeared within the first 15 min of chase. After enzymatic removal of the leader in a late Golgi apparatus compartment, the IP followed one of two routes: (1) to the plasma membrane and hence to the culture supernatant, or (2) to a Golgi or post-Golgi compartment from which secretion was restricted. Combined secretion and intracellular retention of the IP reflected either saturation of a Golgi or post-Golgi compartment and secretion as a consequence of overexpression, or competition between secretion and intracellular retention. IP which was misfolded, either due to amino acid substitution or because disulphide bond formation had been prevented with dithiothreitol (DTT), was transported from the ER to the Golgi apparatus but then retained in a Golgi or post-Golgi compartment and not exported to the culture supernatant.

Secretory expression and characterization of insulin in Pichia pastoris.

The yeasts Pichia pastoris and Saccharomyces cerevisiae have similar overall features regarding the secretory expression of insulin. The S. cerevisiae mating factor alpha (alpha-factor) prepro-leader facilitated the secretion of an insulin precursor, but not proinsulin expressed in P. pastoris. Synthetic prepro-leaders developed for the secretory expression of the insulin precursor in S. cerevisiae also facilitated the secretion of the insulin precursor expressed in P. pastoris. In contrast with S. cerevisiae, only insulin precursor and no unprocessed hyperglycosylated alpha-factor pro-leader/insulin precursor fusion protein was secreted from P. pastoris. A spacer peptide in the fusion protein increased the fermentation yield of the insulin precursor in P. pastoris. A synthetic prepro-leader, but not an alpha-factor prepro-leader lacking N-glycosylation sites, facilitated the secretion of the insulin precursor in P. pastoris. P. pastoris has a capacity for secretory expression of the insulin precursor that is equal to or better than that of S. cerevisiae. Peptide mapping and MS indicated a structure of the insulin precursor expressed in P. pastoris identical with that of human insulin.

alpha-Factor pro-peptide N-linked oligosaccharides facilitate secretion of the insulin precursor in Saccharomyces cerevisiae.

To evaluate the possible relationship between N-linked glycosylation of the Saccharomyces cerevisiae alpha-factor pro-peptide and transport of the alpha-factor pro-peptide/insulin precursor fusion protein through the Saccharomyces cerevisiae secretory pathway, we analysed secretion of insulin precursor facilitated by alpha-factor pro-peptides with one or more of the three N-linked glycosylation sites removed. Mutation of the three alpha-factor pro-peptide N-linked glycosylation sites drastically decreased insulin precursor secretion. The three alpha-factor pro-peptide N-linked glycosylation sites differ in their ability to facilitate secretion of the insulin precursor. The two alpha-factor pro-peptide N-linked glycosylation sites localized closest to the insulin precursor contributed significantly to secretion, whereas the most N-terminally linked glycosylation site did not appear to facilitate secretion. Only correctly folded insulin precursor was found in the culture supernatant, regardless of the pro-peptide used for secretion, indicating that alpha-factor pro-peptide N-linked oligosaccharide chains are not necessary for correct folding of the insulin precursor. Thus, N-linked glycosylation facilitates intracellular transport of the alpha-factor propeptide/insulin precursor fusion protein through the Saccharomyces cerevisiae secretory pathway and secretion of the insulin precursor. N-linked glycosylation per se is not sufficient to facilitate secretion of the insulin precursor; the position of the N-linked oligosaccharide chain on the alpha-factor pro-peptide is important for facilitating efficient secretion.

Prepro-leaders lacking N-linked glycosylation for secretory expression in the yeast Saccharomyces cerevisiae.

Synthetic prepro-leaders lacking consensus N-linked glycosylation sites confers secretion competence of correctly folded insulin precursor expressed in the yeast species Saccharomyces cerevisiae with a yield comparable to, or better than the alpha-factor prepro-leader. In contrast, the S. cerevisiae alpha-factor prepro-leader's three N-linked oligosaccharide chains are necessary for the ability to facilitate secretion of the insulin precursor from S. cerevisiae (T. Kjeldsen et al., Biotechnol. Appl. Biochem. 27, 109-115, 1998). Synthetic prepro-leader lacking both N-glycosylation and the dibasic Kex2 endoprotease processing site also efficiently facilitated secretion of a pro-leader/insulin precursor fusion protein in which the insulin precursor was correctly folded. The unprocessed pro-leader/insulin-precursor fusion protein was purified from culture medium and matured in vitro to desB30 insulin by Achromobacter lyticus lysyl-specific protease providing an alternative yeast expression system not dependent on the Kex2 endoprotease. The synthetic prepro-leader lacking N-linked glycosylation provides the opportunity for secretory expression in yeast utilizing either in vivo Kex2 endoprotease maturation of the fusion protein during secretion or in vitro maturation of the purified fusion protein with a suitable enzyme.

Alanine scanning mutagenesis of insulin.

Alanine scanning mutagenesis has been used to identify specific side chains of insulin which strongly influence binding to the insulin receptor. A total of 21 new insulin analog constructs were made, and in addition 7 high pressure liquid chromatography-purified analogs were tested, covering alanine substitutions in positions B1, B2, B3, B4, B8, B9, B10, B11, B12, B13, B16, B17, B18, B20, B21, B22, B26, A4, A8, A9, A12, A13, A14, A15, A16, A17, A19, and A21. Binding data on the analogs revealed that the alanine mutations that were most disruptive for binding were at positions TyrA19, GlyB8, LeuB11, and GluB13, resulting in decreases in affinity of 1,000-, 33-, 14-, and 8-fold, respectively, relative to wild-type insulin. In contrast, alanine substitutions at positions GlyB20, ArgB22, and SerA9 resulted in an increase in affinity for the insulin receptor. The most striking finding is that B20Ala insulin retains high affinity binding to the receptor. GlyB20 is conserved in insulins from different species, and in the structure of the B-chain it appears to be essential for the shift from the alpha-helix B8-B19 to the beta-turn B20-B22. Thus, replacing GlyB20 with alanine most likely modifies the structure of the B-chain in this region, but this structural change appears to enhance binding to the insulin receptor.

Synthetic leaders with potential BiP binding mediate high-yield secretion of correctly folded insulin precursors from Saccharomyces cerevisiae.

Secretion leaders are essential for expression of many heterologous proteins including insulin in yeast. The function of secretion leaders and their interaction with the secretory pathway is not clear. To determine what constitutes functional pre-pro-leader sequences in Saccharomyces cerevisiae, synthetic leader sequences for secretion of the insulin precursor were developed by a combination of rational design and stepwise systematic optimization. The synthetic leaders efficiently facilitate secretion of the insulin precursor from S. cerevisiae when compared with the alpha-factor leader, leading to a high yield of correctly folded insulin precursor in the culture supernatant. The synthetic leaders feature two potential N-linked glycosylation sites which are efficiently glycosylated during secretion. Pulse-chase analysis indicates that the synthetic leaders/insulin precursor fusion protein have a prolonged residence in the endoplasmic reticulum compared to the alpha-factor leader/insulin precursor fusion protein. The longer transition time in the endoplasmic reticulum mediated by the synthetic leaders might provide additional time for correct folding of the insulin precursor and account for the increased fermentation yield.

A removable spacer peptide in an alpha-factor-leader/insulin precursor fusion protein improves processing and concomitant yield of the insulin precursor in Saccharomyces cerevisiae.

An alpha-factor leader/insulin precursor fusion protein was produced in Saccharomyces cerevisiae and metabolically labeled in order to analyse the efficiency of maturation and secretion. A substantial fraction of the secreted material was found in a hyperglycosylated unprocessed form, indicating incomplete Kex2p endopeptidase maturation. Introduction of a spacer peptide (EAEAEAK) after the dibasic Kex2p site, creating a N-terminal extension of the insulin precursor, greatly increased the Kex2p catalytic efficiency and the fermentation yield of insulin precursor. The N-terminal extension features a Lys to allow subsequent proteolytic removal by trypsin or the Achromobacter lyticus Lys-specific protease. Dipeptidyl aminopeptidase A (DPAPA) activity removing Glu-Ala dipeptides from the extension was inhibited by adding a Glu N-terminally to the extension. Unexpectedly, this modified N-terminal extension (EEAEAEAK) was partially cleaved after the Lys during fermentation. This monobasic proteolytic activity was demonstrated to be associated with Yap3p. Yap3p cleavage could be prevented by insertion of a Pro before the Lys (EEAEAEAPK).

A single-chain insulin-like growth factor I/insulin hybrid binds with high affinity to the insulin receptor.

1. To investigate the structure/function relationship of the interaction between ligand and receptor in the insulin-like growth factor I (IGF-I) and insulin receptor systems we have prepared and characterized a single-chain insulin/IGF-I hybrid. The single-chain hybrid consists of the insulin molecule combined with the C domain of IGF-I. The single-chain hybrid was found to bind with high affinity to both truncated soluble insulin receptors and membrane-bound holoreceptors. The affinity for interacting with the soluble truncated insulin receptors was 55-94% relative to insulin, and affinity for membrane-bound insulin receptors was 113% of that of insulin. Furthermore we found that the affinity of the single-chain hybrid molecule for IGF-I receptors was 19-28% relative to IGF-I. 2. The affinity of the single-chain hybrid for chimeric insulin/IGF-I receptors exceeded that of either natural ligand. This indicates that coordinately changing domains of the receptors and the ligands can induce higher affinity of ligand for receptor, supporting the idea that these receptors have a common ligand-binding site [Kjeldsen, Andersen, Wiberg, Rasmussen, Schäffer, Balschmidt, Møller and Møller (1991) Proc. Natl. Acad. Sci. U.S.A. 88, 4404-4408]. 3. In contrast with what was generally assumed about the ligand structure required for binding to the insulin receptor we demonstrate the first single-chain insulin analogue that can bind with high affinity to the insulin receptor.

Determination by photoaffinity labelling of the hydrophobic part of the binding site for acyl-CoA esters on acyl-CoA-binding protein from bovine liver.

Acyl-CoA esters containing the photoreactive acids 12-(4'-azido-2'-nitrophenoxy)[1-14C]dodecanoic acid ([14C]AND-acid) or N-(4'-azido-2'-nitro-[3'-5'-3H]phenyl)-12-aminododecanoic acid ([3H]NANPA-acid) were synthesized. The photoreactive acyl-CoA esters could be bound to bovine acyl-CoA-binding protein (ACBP) and photocrosslinked to the protein. The photocrosslinked acyl-CoA-ACBP complex was separated from unlabelled ACBP on reverse-phase h.p.l.c. and the purified complex was digested with trypsin, Staphylococcus aureus V8 proteinase or endoproteinase Asp-N. By four independent peptide maps it was shown that the amino acids taking part in forming the hydrophobic binding site for acyl-CoA esters in bovine ACBP are located on the peptide segment from Asp21 to Asp38. Both photoreactive acyl-CoA esters used in this study labelled strongly in the segment from Tyr28 to Ala34. 12-(4'-Azido-2'-nitrophenoxy)[1-14C]-dodecanoyl-CoA ([14C]AND-CoA) also introduced a label at position Asp38, but o labelling was found before Ser29. In contrast, N-(4'-azido-2'-nitro[3',5'-3H]phenyl)-12-aminododecanoyl-CoA [3H]NANPA-CoA) also labelled the segment from Asp21 to Tyr28. The difference in labelling by the two photoreactive ligands is most likely caused by different mobility of the arylazido group when linked to the fatty acid either through a phenolic O- or an anilinic N- bond.