A relatively small but influential economics literature is devoted to financial abuse in Medicare... more A relatively small but influential economics literature is devoted to financial abuse in Medicare. Much of that literature focuses on upcoding/no upcoding for inpatient hospital care in Medicare Part A, where reimbursements requested are greater/the same as justified by the cost of care provided. Analysis of Medicare claims data from 1985 -- 1996 suggested that upcoding was a substantial issue. We used a different approach to examine this issue from 2011 -- 2019, analyzing audit data from the Comprehensive Error Rate Testing program (CERT). Upcoding represented less than 0.5% of all Medicare fee-for-service reimbursements, a small fraction of improper bills for hospitalization, and was not significantly correlated with diagnosis related group (DRG) weights. Audit data does not discriminate between intentional (fraudulent) and unintentional upcoding. We therefore used Office of the Inspector General reports, showing that of all cases successfully prosecuted for healthcare fraud from 2013 -- 2019, only 0.39% were for upcoding of hospital admissions, or 7.2% of all prosecutions for hospitals. Other forms of improper billing/fraud constituted more than 90% of all cases, both for hospital admissions and for Medicare Part B, paid on a fee-for-service basis.
Academic medicine : journal of the Association of American Medical Colleges, Jan 7, 2018
To identify the factors associated with total Hospital-Acquired Condition Reduction Program (HACR... more To identify the factors associated with total Hospital-Acquired Condition Reduction Program (HACRP) score and with receiving a Centers for Medicare and Medicaid Services (CMS) penalty (1% reduction in payment to those hospitals in the lowest-performing quartile of HACRP scores) for fiscal years (FYs) 2015-2017 with a particular focus on trends over this period. The authors evaluated the following variables: (1) type of hospital (teaching vs. nonteaching); (2) disproportionate patient percentage; (3) case mix index (CMI); (4) number of staffed beds; (5) length of stay (LOS); (6) gross patient revenue; and (7) region, using data from CMS and the American Hospital Directory. They conducted multivariate linear and logistic regressions. A total of 2,249 hospitals were included. The mean total HACRP scores across hospitals for FY15, FY16, and FY17 were 5.38, 5.35, and 5.18, respectively. In FY15, 21.2% (476/2,249) of hospitals received a penalty compared to 22.6% (508/2,249) in FY16 and 3...
Microbial Surface Components and Toxins in Relation to Pathogenesis, 1991
Lipopolysaccharide (LPS) is an important virulence determinant of gram-negative bacteria. It is c... more Lipopolysaccharide (LPS) is an important virulence determinant of gram-negative bacteria. It is comprised of three regions: the O-antigenic polysaccharide chain, the R-specific core polysaccharide, and the lipid A region, which exerts, when soluble, all the endotoxic activities of LPS.
The club-shaped rhoptries in Apicomplexan parasites are one of the most unusual secretory organel... more The club-shaped rhoptries in Apicomplexan parasites are one of the most unusual secretory organelles among the eukaryotes, containing unusual lipid and protein cargo that is specialized for intracellular parasitism. Rhoptries have traditionally been viewed strictly as regulated secretory granules. We discuss in this article recent data on the cargo, function and biogenesis of rhoptries in two parasitic model systems, Toxoplasma and Plasmodium. Current findings suggest that rhoptries receive products from both biosynthetic and endocytic pathways and, therefore, they are most analogous to secretory lysosomal granules found in mammalian cells.
Intracellular parasites of the phylum Apicomplexa contain specialized rhoptry secretory organelle... more Intracellular parasites of the phylum Apicomplexa contain specialized rhoptry secretory organelles that have a crucial function in host-cell invasion and establishment of the parasitophorous vacuole. Here we show that localization of the Toxoplasma gondii rhoptry protein ROP2 is dependent on a YEQL sequence in the cytoplasmic tail that binds to micro-chain subunits of T. gondii and mammalian adaptors, and conforms to the YXXstraight phi mammalian sorting motif. Chimaeric reporters, containing the transmembrane domains and cytoplasmic tails of the low-density lipoprotein receptor and of Lamp-1, are sorted to the Golgi or the trans-Golgi network (TGN), and partially to apical microneme organelles of the parasite, respectively. Targeting of these reporters is mediated by YXXstraight phi- and NPXY-type signals. This is the first demonstration of tyrosine-dependent sorting in protozoan parasites, indicating that T. gondii proteins may be targeted to, and involved in biogenesis of, morphologically unique organelles through the use of evolutionarily conserved signals and machinery.
Lipoteichoic acids (LTAs) belong to the immunostimulatory class of molecules of gram-positive bac... more Lipoteichoic acids (LTAs) belong to the immunostimulatory class of molecules of gram-positive bacteria (GPB). Previous investigations showed that the macrophage scavenger receptor (SR), a glycosylated trimeric transmembrane protein, binds directly to many GPB, possibly via LTA. SR binding to other ligands is dependent upon the spatial characteristics of the repeating negative charge of the ligand. We therefore investigated SR recognition of LTA species with various charge densities and distributions by determining the capacity of these LTAs to compete with the binding of metabolically labeled SR to beads coated with the known SR ligand polyguanylic acid. Staphylococcus aureus LTA, a classical LTA type (unbranched 1,3-linked polyglycerophosphate chain covalently bound to a membrane diacylglyceroglycolipid), had a 50% inhibitory concentration (IC50) for inhibition of SR binding of 0.84 microg/ml. When the S. aureus LTA was rendered more negatively charged by removal of ester-linked al...
We explored the interaction of human recombinant mannose-binding protein and lipoteichoic acids (... more We explored the interaction of human recombinant mannose-binding protein and lipoteichoic acids (LTAs) by enzyme-linked immunosorbent assay. The best ligand was Micrococcus luteus lipomannan, followed by Enterococcus spp. LTA containing mono-, di-, and oligoglucosyl substituents. LTAs lacking terminal sugars (those of Streptococcus pyogenes and Staphylococcus aureus) or containing galactosyl substituents (those of Listeria spp. and Lactococcus spp.) were poor ligands. These results are consistent with known structural requirements for binding through the mannose-binding protein carbohydrate recognition domain.
The survival of Salmonella montevideo during serum treatment depends on the presence of an O anti... more The survival of Salmonella montevideo during serum treatment depends on the presence of an O antigen (O-Ag) associated with the lipopolysaccharide molecule. In this organism, the O antigen is a polysaccharide composed of 0 to more than 55 subunits, each containing 4 mannose residues together with glucose and n-acetylglucosamine. We used a mutant strain of S. montevideo that requires exogenous mannose for the synthesis of O-Ag. Lipopolysaccharide (LPS) was prepared from these cells grown under three different conditions where the availability of exogenous mannose was regulated such that the average number of O-Ag units per LPS molecule, the percentage of LPS molecules bearing long O-Ag side chains, and the percentage of lipid A cores bearing O-Ag were all varied. These changes in LPS profiles were monitored on sodium dodecyl sulfate-polyacrylamide gels, and cells with different LPS profiles were tested for their ability to survive treatment with pooled normal human serum. Survival in...
ABSTRACT An inverse relationship exists between the sialic acid content of a particle and its abi... more ABSTRACT An inverse relationship exists between the sialic acid content of a particle and its ability to activate the alternative complement pathway. The present studies were performed to determine if the neuraminidase (NANase) activities of different mumps virus strains could influence the ability of mumps virus infected cells to activate the alternative pathway. CV-1 cells were infected with three different mumps virus strains (RW, O'Take, and Kilham) and after 24 hours, 10 percent guinea pig serum (GPS) treated with EGTA/MgCl2 or GPS lacking the 4th component of complement (C4DGPS) was added to the cell monolayers. After 30 minutes, the percentage C3 consumed was determined by a functional hemolytic assay. Cells infected with RW (high NANase) consumed significantly more C3 (23.2 per cent) than cells infected with Kilham (5.7 percent, low NANase). Cells infected with O'Take were intermediate in their ability to activate C3. The degree of C3 deposition on the surface of infected cells, detected by fluorescence microscopy, was also greater for cells infected with the RW than the Kilham strain of mumps virus. These studies suggest that the NANase activity of mumps virus can influence the ability of infected cells to activate the alternative pathway and thereby, the ability of complement to participate in host defense against mumps virus infection.
A relatively small but influential economics literature is devoted to financial abuse in Medicare... more A relatively small but influential economics literature is devoted to financial abuse in Medicare. Much of that literature focuses on upcoding/no upcoding for inpatient hospital care in Medicare Part A, where reimbursements requested are greater/the same as justified by the cost of care provided. Analysis of Medicare claims data from 1985 -- 1996 suggested that upcoding was a substantial issue. We used a different approach to examine this issue from 2011 -- 2019, analyzing audit data from the Comprehensive Error Rate Testing program (CERT). Upcoding represented less than 0.5% of all Medicare fee-for-service reimbursements, a small fraction of improper bills for hospitalization, and was not significantly correlated with diagnosis related group (DRG) weights. Audit data does not discriminate between intentional (fraudulent) and unintentional upcoding. We therefore used Office of the Inspector General reports, showing that of all cases successfully prosecuted for healthcare fraud from 2013 -- 2019, only 0.39% were for upcoding of hospital admissions, or 7.2% of all prosecutions for hospitals. Other forms of improper billing/fraud constituted more than 90% of all cases, both for hospital admissions and for Medicare Part B, paid on a fee-for-service basis.
Academic medicine : journal of the Association of American Medical Colleges, Jan 7, 2018
To identify the factors associated with total Hospital-Acquired Condition Reduction Program (HACR... more To identify the factors associated with total Hospital-Acquired Condition Reduction Program (HACRP) score and with receiving a Centers for Medicare and Medicaid Services (CMS) penalty (1% reduction in payment to those hospitals in the lowest-performing quartile of HACRP scores) for fiscal years (FYs) 2015-2017 with a particular focus on trends over this period. The authors evaluated the following variables: (1) type of hospital (teaching vs. nonteaching); (2) disproportionate patient percentage; (3) case mix index (CMI); (4) number of staffed beds; (5) length of stay (LOS); (6) gross patient revenue; and (7) region, using data from CMS and the American Hospital Directory. They conducted multivariate linear and logistic regressions. A total of 2,249 hospitals were included. The mean total HACRP scores across hospitals for FY15, FY16, and FY17 were 5.38, 5.35, and 5.18, respectively. In FY15, 21.2% (476/2,249) of hospitals received a penalty compared to 22.6% (508/2,249) in FY16 and 3...
Microbial Surface Components and Toxins in Relation to Pathogenesis, 1991
Lipopolysaccharide (LPS) is an important virulence determinant of gram-negative bacteria. It is c... more Lipopolysaccharide (LPS) is an important virulence determinant of gram-negative bacteria. It is comprised of three regions: the O-antigenic polysaccharide chain, the R-specific core polysaccharide, and the lipid A region, which exerts, when soluble, all the endotoxic activities of LPS.
The club-shaped rhoptries in Apicomplexan parasites are one of the most unusual secretory organel... more The club-shaped rhoptries in Apicomplexan parasites are one of the most unusual secretory organelles among the eukaryotes, containing unusual lipid and protein cargo that is specialized for intracellular parasitism. Rhoptries have traditionally been viewed strictly as regulated secretory granules. We discuss in this article recent data on the cargo, function and biogenesis of rhoptries in two parasitic model systems, Toxoplasma and Plasmodium. Current findings suggest that rhoptries receive products from both biosynthetic and endocytic pathways and, therefore, they are most analogous to secretory lysosomal granules found in mammalian cells.
Intracellular parasites of the phylum Apicomplexa contain specialized rhoptry secretory organelle... more Intracellular parasites of the phylum Apicomplexa contain specialized rhoptry secretory organelles that have a crucial function in host-cell invasion and establishment of the parasitophorous vacuole. Here we show that localization of the Toxoplasma gondii rhoptry protein ROP2 is dependent on a YEQL sequence in the cytoplasmic tail that binds to micro-chain subunits of T. gondii and mammalian adaptors, and conforms to the YXXstraight phi mammalian sorting motif. Chimaeric reporters, containing the transmembrane domains and cytoplasmic tails of the low-density lipoprotein receptor and of Lamp-1, are sorted to the Golgi or the trans-Golgi network (TGN), and partially to apical microneme organelles of the parasite, respectively. Targeting of these reporters is mediated by YXXstraight phi- and NPXY-type signals. This is the first demonstration of tyrosine-dependent sorting in protozoan parasites, indicating that T. gondii proteins may be targeted to, and involved in biogenesis of, morphologically unique organelles through the use of evolutionarily conserved signals and machinery.
Lipoteichoic acids (LTAs) belong to the immunostimulatory class of molecules of gram-positive bac... more Lipoteichoic acids (LTAs) belong to the immunostimulatory class of molecules of gram-positive bacteria (GPB). Previous investigations showed that the macrophage scavenger receptor (SR), a glycosylated trimeric transmembrane protein, binds directly to many GPB, possibly via LTA. SR binding to other ligands is dependent upon the spatial characteristics of the repeating negative charge of the ligand. We therefore investigated SR recognition of LTA species with various charge densities and distributions by determining the capacity of these LTAs to compete with the binding of metabolically labeled SR to beads coated with the known SR ligand polyguanylic acid. Staphylococcus aureus LTA, a classical LTA type (unbranched 1,3-linked polyglycerophosphate chain covalently bound to a membrane diacylglyceroglycolipid), had a 50% inhibitory concentration (IC50) for inhibition of SR binding of 0.84 microg/ml. When the S. aureus LTA was rendered more negatively charged by removal of ester-linked al...
We explored the interaction of human recombinant mannose-binding protein and lipoteichoic acids (... more We explored the interaction of human recombinant mannose-binding protein and lipoteichoic acids (LTAs) by enzyme-linked immunosorbent assay. The best ligand was Micrococcus luteus lipomannan, followed by Enterococcus spp. LTA containing mono-, di-, and oligoglucosyl substituents. LTAs lacking terminal sugars (those of Streptococcus pyogenes and Staphylococcus aureus) or containing galactosyl substituents (those of Listeria spp. and Lactococcus spp.) were poor ligands. These results are consistent with known structural requirements for binding through the mannose-binding protein carbohydrate recognition domain.
The survival of Salmonella montevideo during serum treatment depends on the presence of an O anti... more The survival of Salmonella montevideo during serum treatment depends on the presence of an O antigen (O-Ag) associated with the lipopolysaccharide molecule. In this organism, the O antigen is a polysaccharide composed of 0 to more than 55 subunits, each containing 4 mannose residues together with glucose and n-acetylglucosamine. We used a mutant strain of S. montevideo that requires exogenous mannose for the synthesis of O-Ag. Lipopolysaccharide (LPS) was prepared from these cells grown under three different conditions where the availability of exogenous mannose was regulated such that the average number of O-Ag units per LPS molecule, the percentage of LPS molecules bearing long O-Ag side chains, and the percentage of lipid A cores bearing O-Ag were all varied. These changes in LPS profiles were monitored on sodium dodecyl sulfate-polyacrylamide gels, and cells with different LPS profiles were tested for their ability to survive treatment with pooled normal human serum. Survival in...
ABSTRACT An inverse relationship exists between the sialic acid content of a particle and its abi... more ABSTRACT An inverse relationship exists between the sialic acid content of a particle and its ability to activate the alternative complement pathway. The present studies were performed to determine if the neuraminidase (NANase) activities of different mumps virus strains could influence the ability of mumps virus infected cells to activate the alternative pathway. CV-1 cells were infected with three different mumps virus strains (RW, O'Take, and Kilham) and after 24 hours, 10 percent guinea pig serum (GPS) treated with EGTA/MgCl2 or GPS lacking the 4th component of complement (C4DGPS) was added to the cell monolayers. After 30 minutes, the percentage C3 consumed was determined by a functional hemolytic assay. Cells infected with RW (high NANase) consumed significantly more C3 (23.2 per cent) than cells infected with Kilham (5.7 percent, low NANase). Cells infected with O'Take were intermediate in their ability to activate C3. The degree of C3 deposition on the surface of infected cells, detected by fluorescence microscopy, was also greater for cells infected with the RW than the Kilham strain of mumps virus. These studies suggest that the NANase activity of mumps virus can influence the ability of infected cells to activate the alternative pathway and thereby, the ability of complement to participate in host defense against mumps virus infection.
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Papers by Keith Joiner