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Background: Covid-19 toll is disproportionate in Blacks although the mechanisms remain incompletely understood. From a biological perspective, several host proteins have received most attention as logical susceptibility targets. Specifically, angiotensin-converting enzyme 2 (ACE2) serves as the epithelial cell receptor and acts in concert with transmembrane protease serine 2 (TMPRSS2). Intriguingly, ACE2 can also suppress the inflammatory response and therefore may impact the severity of Covid-19 infections (from the exuberant immune response a.k.a. “cytokine storm”). We, therefore, assessed expression of ACE2 and TMPRSS2 in Blacks versus Whites. Methods: Archived mucosal biopsies from colonoscopic biopsies of visually normal rectal mucosa without concurrent neoplasia or inflammation were used for this study. Total mRNA was isolated and subjected to real-time polymerase chain reaction for ACE2, and TMPRSS2 was assessed from non-Hispanic Blacks (n= 45) and non-Hispanic Whites (n= 38). GAPDH and beta-actin were used for normalization. Multivariable analysis was performed using Analyse-IT software. Results: ACE2 and TMPRSS2 levels were not altered by gender, BMI, or age. ACE2 levels were lower in Blacks than Whites achieving statistical significance in multivariable (0.51-fold, p= 0.03) but not quite in univariable (p= 0.07) analysis. This downregulation was mirrored in TMRPSS2 in both univariable (p= 0.03) and multivariable analyses (0.41-fold, p= 0.02). Moreover, there was a strong correlation between ACE2 and TMPRSS2 levels (r-squared = 0.78). Conclusions: To our knowledge, this is the first report on racial differences inACE2 and TMPRSS2 mucosal expression. This may provide potential biological underpinnings for the disproportionately higher mortality of Covid-19 in Blacks and should spur future studies.

Patients hospitalized with COVID-19 suffer thrombotic complications. Risk factors for poor outcomes are shared with coronary artery disease.

Calcium carbonate limestone filler is used as a partial replacement for clinker in cements to reduce carbon dioxide emissions and fill the voids in the cement paste. However, concrete durability conditions depend on the composition and the water/cement ratio, one of the major origin of concrete´s porosity. The objective of this study was to evaluate physical and chemical effects of calcium carbonate limestone filler in mortar pastes subjected to accelerated carbonation. Composite formulations were elaborated with three proportions of filler substitution (15%, 25% and 35%) and three water/cement ratios (0.42, 0.50 and 0.58). Physical, chemical and mineral characterizations were performed on Portland cement PC V and calcium carbonate limestone. The resulting mortar paste formulations were evaluated with respect to mechanical strength and capillary water absorption both for samples without carbonation and with accelerated exposure conditions. In the latter, carbonation depth penetration was also ascertained. Carbonation effects were determined from X-ray diffraction and thermogravimetric analysis. Results on compression strength and water absorption determined that a 25% filler substitution achieved the best performance with 40.72 MPa and an absorption of up to 7% for the water/cement ratio of 0.42. The carbonation coefficient was primarily affected by the water/cement ratio rather than substitution level. Thermal and mineral analysis indicated that carbonation consumed portlandite and formed calcite. Further calcium carbonate polymorphs were identified after 28 days of accelerated carbonation as a result so far unreported in studies of Portland cement.

ABSTRACTDocumented treatment rates for Hepatitis C virus (HCV) infection are low. Within this cohort of HCV-infected patients (N = 373), participants who were not actively injecting drugs or not co-infected with HIV were most likely to initiate HCV treatment. Persons of white race and HIV-infected participants with a CD4 count above 200 were also more likely to have initiated HCV treatment. We defined five factors as potentially modifiable, and found almost all (90%) of the cohort had at least one such factor. Participants with more than one of these factors were least likely to initiate treatment. The proportion of patients receiving treatment increased as their number of modifiable risk factors decreased (p < 0.01, for trend). Focused strategies to overcome these potentially modifiable factors may be indicated to increase HCV treatment in affected populations.

Background: Coinfection of human immunodeficiency virus (HIV) and hepatitis C virus (HCV) is a substantial medical and public health concern due to its increasing prevalence and complex patient management. Alcohol use may worsen HCV‐related liver disease and interfere with adherence to antiretroviral therapy (ART) and medical care. We therefore studied the association between HCV infection and markers of HIV disease progression in adults with alcohol problems.

Pediatric management of complicated pleural effusion (CPE) remains controversial. Different approaches include antibiotics and chest tube drainage alone or the use of fibrinolitics, videothorascoscopy (VTC) and surgical decortication through thoracotomy.

Alcohol use and human immune deficiency virus (HIV) infection are both associated with accelerated progression of hepatitis C virus (HCV) disease and reduced response rates to interferon therapy. In this study, we assessed the prevalence of barriers to interferon treatment in a population of HIV/HCV-coinfected patients with current or past alcohol problems and the extent to which they received treatment to address the barriers.

The transmembrane mucin, MUC1, is overexpressed on many human carcinoma cells, increasing their metastatic potential through decreased cell-cell and cell-matrix adhesion. These cellular changes are mediated both through the altered physical properties of the mucin itself and through the role of the MUC1 cytoplasmic domain as a signaling molecule. The epidermal growth factor receptor (EGFR) is also overexpressed in many cancers and both it and MUC1 constitute important therapeutic targets. In the present study, expression of MUC1 was downregulated by treatment of KB carcinoma cells with a MUC1 small interfering RNA resulting in an inhibition of cell proliferation and colony formation and an increase in cell-cell aggregation. Surprisingly, suppression of MUC1 also inhibited expression of EGFR at both the mRNA and protein levels whereas the reciprocal effect was not observed. These results demonstrate a role for MUC1 in the regulation of EGFR expression and suggest that MUC1 gene silencing may represent a novel therapeutic approach in the treatment of a variety of human cancers.

Mucins are high molecular weight glycoproteins secreted by salivary glands and epithelial cells lining the digestive, respiratory, and reproductive tracts. These glyco-proteins, encoded in at least 13 distinct human genes, can be subdivided into gel-forming and membrane-associated forms. The gel-forming mucin MUC5B is secreted by mucous acinar cells in major and minor salivary glands, but little is known about the expression pattern of membrane-associated mucins. In this study, RT-PCR and Northern blotting demonstrated the presence of transcripts for MUC1 and MUC4 in both parotid and submandibular glands, and in situ hybridization localized these transcripts to epithelial cells lining striated and excretory ducts and in some serous acinar cells. The same cellular distribution was observed by immunohistochemistry. Soluble forms of both mucins were detected in parotid secretion after immunoprecipitation with mucin-specific antibodies. These studies have shown that membrane-associated mucins are produced in both parotid and submandibular glands and that they are expressed in different cell types than gel-forming mucins. Although the function of these mucins in the oral cavity remains to be elucidated, it is possible that they both contribute to the epithelial protective mucin layer and act as receptors initiating one or more intracellular signal transduction pathways.

The prevalence of clinical celiac disease has been shown to vary both across time and between genetically similar populations. Differences in wheat antigenicity and transglutaminase substrate properties are a possible explanation for these differences. This study assessed the antigenicity and transglutaminase substrate specificities of gliadins from regions of high and low celiac disease prevalence. Gliadin was extracted from three commercial US wheat sources and two Irish sources. SDS-PAGE and western blotting revealed minor, but significant variations in the gliadin extracts. However, ELISA showed no difference in the antigenicity of these gliadins. Transglutaminase pretreatment of gliadin resulted in no significant change in gliadin antigenicity and kinetic studies showed that the Kms of the various gliadins were very similar. Purified IgA and IgG had no effect on transglutaminase activity. In summary, minor variations in wheat gliadins are unlikely to explain the observed differences in disease expression across genetically similar populations.

Background & Aims:Mucin has a central role in the pathogenesis of cholesterol gallstones, in part because of its ability to bind biliary lipids and accelerate cholesterol crystal appearance time. Previous studies have localized these properties to nonglycosylated mucin domains, and we have recently shown that these domains contain a series of 127−amino acid, cysteine-rich repeats. The aim of this study was to express a recombinant mucin polypeptide containing these repeats and investigate its lipid-binding and pronucleating properties. Methods:A recombinant mucin polypeptide was expressed as a glutathione S-transferase fusion protein in Escherichia coli,purified by affinity chromatography, and compared with native bovine gallbladder mucin in lipid-binding and cholesterol crystal appearance time assays. Results:The recombinant mucin polypeptide bound a hydrophobic fluorescent probe and cholesterol in a concentration-dependent manner. It accelerated the appearance of cholesterol crystals from lithogenic model bile, an effect that was both time and concentration dependent. Conclusions:The cysteine-rich repeats in the recombinant mucin polypeptide correspond to the protease-sensitive hydrophobic domains identified in earlier biochemical studies. Further delineation of the lipid-binding site(s) in these repeats will provide new insights into the mechanism of cholesterol crystal nucleation and stone growth.

The MUC5B mucin gene product is expressed in a wide variety of secretory epithelia including the gallbladder, salivary glands, trachea, and colon. Previous studies by us and others have described the C-terminal region as well as the central tandem repeating domain of this mucin. In an effort to understand the functional role of MUC5B in diverse human tissues, the sequence encoding the N-terminal region of this mucin was determined from the sequences of exons in three overlapping genomic clones. Primer extension mapped the site of transcription initiation 25 bp downstream from a putative TATA box element. The N-terminal region of MUC5B contained 1321 amino acids organized into a signal peptide, a short serine-threonine rich region, and three von Willebrand factor-like D domains. Comparison of this sequence with the N-terminal sequences of MUC2 and MUC5AC revealed a much higher degree of identity (46–59%) than that observed in the C-terminal regions of these mucins (33%). The N-terminal sequence of MUC5B also contains a number of sequence motifs common to several groups of extracellular ligand binding and adhesion proteins not previously recognized in mammalian gel-forming mucins. The N-terminal D domains in MUC5B are likely to have important roles in both mucin assembly and in the protective functions of the secreted mucin.

Recent advances in the study of gallstone pathogenesis have focused on alterations in biliary lipids and proteins and on models of biliary hypomotility. The importance of both the concentration and composition of phospholipids in solubilizing cholesterol has been investigated. Several biliary proteins that promote cholesterol crystal nucleation and growth, including gallbladder mucin, immunoglobulins, aminopeptidase N, and α1-acid glycoprotein have been further characterized. Animal models have provided increasing evidence for neuronal control of gallbladder motility. Studies in each of these areas have contributed to our still incomplete understanding of the mechanisms of cholesterol stone formation.

Gall bladder mucin has been shown to play a central role in the pathogenesis of cholesterol gallstone disease. While cloning and sequencing studies have provided a wealth of information on the structure of other gastrointestinal and respiratory mucins, nothing is known about the primary structure of human gall bladder mucin. In this study, we show that the tracheobronchial mucin MUC5B is a major mucin gene product expressed in the gall bladder. Antibodies directed against deglycosylated human gall bladder mucin were used to screen a gall bladder cDNA expression library, and most of the isolated clones contained repetitive sequences nearly identical with those in the tandem repeat region of MUC5B. An additional clone (hGBM2-3) contained an open reading frame coding for a 389 residue cysteine-rich sequence. The arrangement of cysteine residues in this sequence was very similar to that in the C-terminal regions of MUC2, MUC5AC and human von Willebrand factor. This cysteine-rich sequence was connected to a series of degenerate MUC5B tandem repeats in a 7.5 kb HincII genomic DNA fragment. This fragment, with ten exons and nine introns, contained MUC5B repeats in exon 1 and a 469 residue cysteine-rich sequence in exons 2–10 that provided a 152 nucleotide overlap with cDNA clone hGBM2-3. Interestingly, the exon–intron junctions in the MUC5B genomic fragment occurred at positions equivalent to those in the D4 domain of human von Willebrand factor, suggesting that these proteins evolved from a common evolutionary ancestor through addition or deletion of exons encoding functional domains.

High molecular weight salivary mucin (MG1) is an important component of saliva, contributing to the lubricative and tissue-protective functions of this biological fluid. We have shown previously that the human mucin gene MUC5B is expressed at high levels in sublingual gland and is a significant constituent of MG1. Since many epithelia express multiple mucin genes, it seemed likely that MG1 in salivary secretions is also a heterogeneous mixture of mucin gene products. The aim of this study was to determine whether MUC4, a mucin shown in Northern blotting experiments to be expressed in salivary glands, was a significant protein component of MG1 in salivary secretions. Two cDNA clones containing MUC4 tandem repeats were isolated from a human submandibular gland cDNA library. In addition, recombinant MUC4 produced in a bacterial expression system cross-reacted with an antibody directed against deglycosylated MG1. This shows conclusively that human salivary mucin MG1 contains both MUC5B and MUC4 gene products suggesting that each mucin may perform distinct functions in the oral cavity.

Background Treatment eradication rates of Helicobacter pylori, a gastrointestinal infection, are 70% to 90% in clinical studies but lower in real-world settings. Potential barriers include multidrug regimen complexity or prescribing/administration errors. A pharmacist-managed H pyloritreatment service was implemented to address these barriers and optimize treatment outcomes. The clinical pharmacist provided 2 services: (1) treatment education and monitoring for treatment-naïve patients and (2) treatment initiation, education, and monitoring for treatment-experienced patients.Objective We aimed to evaluate the impact of a pharmacist-managed H pyloritreatment service within a gastroenterology clinic.Methods We conducted a retrospective observational cohort study of all patients referred to and seen in the pharmacist-managed H pyloritreatment service from July 10, 2019, to December 31, 2020. Patient demographics, prior treatment history, course(s) of treatment prescribed, frequency of follow-ups, and outcomes posttreatment were collected.Results The clinical pharmacist managed 60 referrals for 55 unique patients over a mean of 5 ± 2 visits. Five patients failed H pyloritreatment and were re-referred. Identified barriers included prescribing/dispensing and administration errors. Posttreatment, 38 referrals tested for H pylorieradication, of which 100% of treatment-naïve patients and 69% of treatment-experienced patients were cured, and 13 (22%) referrals were lost to follow-up.Conclusion and Relevance This study described and assessed the impact of a pharmacist-managed H pyloritreatment service in a gastroenterology clinic, in which various barriers were effectively addressed to optimize treatment outcomes. Future studies should focus on long-term outcome, impact on health care costs, and patient satisfaction with this service.

GASTROENTEROLOGY 1998;114:872

Human submandibular/sublingual gland secretions contain a multimeric high molecular weight mucin (MG1) and a monomeric low molecular weight mucin (MG2). MG2 is the product of the MUC7 gene, whereas the gene for MG1 has not been identified. Previously, we isolated a clone (pSM2–1) from a human sublingual gland cDNA expression library using an antibody against deglycosylated MG1 (Troxler et al., Biochem. Biophys. Res Commun., 217, 1112–1119, 1995). In order to identify the mucin gene from which pPM2–1 was derived, Northern blots of human submandibular and sublingual gland RNA were hybridized with a series of probes for tandem repeats found in the high molecular weight secreted mucins MUC2, MUC3, MUC4, MUC5AC, MUC5B, and MUC6. The only known mucin expressed at high levels in sublingual gland was MUC5B, and no known mucin was expressed at high levels in submandibular gland. A series of overlapping clones was obtained by rescreening the sublingual gland cDNA library and by reverse transcriptase-polymerase chain reaction. The resulting clones connected pSM2–1 to a series of MUC5B tandem repeats at the 3′ end of the repeat domain and provided the complete nucleotide and deduced amino sequence of the carboxyl terminal region of MG1. This region is enriched with respect to cysteine (∼10 mol %) and contained a D domain and a carboxyl terminal domain that could be aligned with the corresponding domains in human intestinal MUC2, human tracheobronchial MUC5AC, and human von Willebrand factor. The limited expression of known mucin genes, together with the considerable mucin synthesizing capacity of submandibular gland, suggests that a novel (previously not described) mucin gene is expressed in this gland and constitutes a portion of MG1 in salivary secretions.