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Biomedical subjects

Philip E Johnson

Publications and source records attributed to Philip E Johnson.

10 recordsLinked to original sources
PubMed2006

Changes in reimbursement rates and rules associated with the Medicare Prescription Drug Improvement and Modernization Act. Introduction.

PURPOSE: Future trends in the Medicare population and drug expenditures, the organizational structure of the Medicare program, and recent changes in Medicare rules and rates for pharmaceutical reimbursement are described. SUMMARY: Large increases in the number of Medicare beneficiaries and drug spending are anticipated in the future. Medicare Part A provides insurance benefits for hospital inpatients, nursing home patients, home health care patients, and hospice care patients. Part B provides benefits for physician services, durable medical equipment, oral chemotherapy, and end-stage renal disease services. For hospitals, Part B rules are followed for ambulatory services, but these services are administered through the Part A Outpatient Prospective Payment System. The average sales price plus 6% is now used for pharmaceutical reimbursement, although physician-owned clinics may participate in a competitive acquisition program under Part B. Payments are the same for generic drugs and brand name products, although they differed in the past. Pharmaceutical reimbursement is available for uses listed in compendia approved by the Centers for Medicare & Medicaid Services and possibly some other authoritative sources. CONCLUSION: Medicare rules and rates for pharmaceutical reimbursement have undergone substantial changes in recent years and will continue to change in the future, with a potentially large impact on health systems and patients.

Aged↗
PubMed2006

Patient assistance programs and patient advocacy foundations: alternatives for obtaining prescription medications when insurance fails.

PURPOSE: The role of patient assistance programs and patient advocacy foundations as a safety net for Americans without health insurance or with inadequate insurance, the financial impact of 14 years of experience promoting enrollment in such programs at a cancer treatment center, and resources and strategies that pharmacists can use to increase patient enrollment and access to needed medications are discussed. SUMMARY: Various patient assistance programs and patient advocacy foundations offer financial and other support for patients who need help obtaining prescription medications because they lack health insurance or their insurance fails to meet their needs. Patients must complete an application and provide personal financial information. Efforts by a pharmacist at a cancer treatment center to enroll patients in such programs produced a marked reduction in write-offs over a 14-year period. Pharmacists can promote patient enrollment in assistance programs by screening for costly drugs and patients who are likely to have difficulty obtaining these drugs. These patients include those who exceed Medicaid coverage or for whom Medicaid coverage is pending, patients without any health insurance, patients without a prescription drug benefit, patients for whom the planned drug therapy is not covered by insurance, and patients enrolled in charity programs. CONCLUSION: Patient assistance programs and patient advocacy foundations provide a valuable safety net to ensure that Americans without health insurance or with inadequate coverage receive needed prescription medications.

Cancer Care Facilities↗
PubMed2006

RNA recognition by the Vts1p SAM domain.

The putative yeast post-transcriptional regulator Vts1p and its related protein Smaug, from Drosophila melanogaster, each use a sterile alpha motif (SAM) domain to bind an RNA hairpin termed the Smaug recognition element (SRE). Here, we present the NMR structures of the Vts1p-SRE complex and the free SRE. Structural highlights include the direct recognition of a guanine base and the formation or stabilization of a base pair in the SRE loop.

Base Pairing↗
PubMed2005

The NMR and X-ray structures of the Saccharomyces cerevisiae Vts1 SAM domain define a surface for the recognition of RNA hairpins.

The SAM domain of the Saccharomyces cerevisiae post-transcriptional regulator Vts1 has a high affinity towards RNA hairpins containing a CUGGC pentaloop. We present the 1.6 Angstroms X-ray crystal structure of the Vts1 SAM domain in its unliganded state, and the NMR solution structure of this domain in its RNA-bound state. Both structures reveal a canonical five helix SAM domain flanked by additional secondary structural elements at the N and C termini. The two structures are essentially identical, implying that no major structural rearrangements occur upon RNA binding. Amide chemical shift changes map the RNA-binding site to a shallow, basic patch at the junction of helix alpha5 and the loop connecting helices alpha1 and alpha2.

Crystallography, X-Ray↗
PubMed2005

Assembly PCR oligo maker: a tool for designing oligodeoxynucleotides for constructing long DNA molecules for RNA production.

We describe a computer program, Assembly PCR Oligo Maker, created to automate the design of oligodeoxynucleotides for the PCR-based construction of long DNA molecules. This program is freely available at http://publish.yorku.ca/~pjohnson/AssemblyPCRoligomaker.html and has been specifically designed to aid in the construction of DNA molecules that are to be used for the production of RNA molecules by in vitro synthesis with T7 RNA polymerase. The input for Assembly PCR Oligo Maker is either the desired DNA sequence to be made or an RNA sequence. If RNA is the input, the program first determines the DNA sequence necessary to produce the desired RNA molecule. The program then determines the sequences of all the oligodeoxynucleotides necessary for a two-step assembly PCR-based synthesis of the desired DNA molecule. The oligodeoxynucleotide sequences outputted are designed to have a uniform melt temperature and are checked for regions of overlap outside of the desired priming regions necessary for the PCR reaction. The validity of the program was verified experimentally by synthesizing a 191-nt long DNA molecule using the DNA sequences suggested by the program.

DNA↗
PubMed2003

A low-starch barley mutant, risø 16, lacking the cytosolic small subunit of ADP-glucose pyrophosphorylase, reveals the importance of the cytosolic isoform and the identity of the plastidial small subunit.

To provide information on the roles of the different forms of ADP-glucose pyrophosphorylase (AGPase) in barley (Hordeum vulgare) endosperm and the nature of the genes encoding their subunits, a mutant of barley, Risø 16, lacking cytosolic AGPase activity in the endosperm was identified. The mutation specifically abolishes the small subunit of the cytosolic AGPase and is attributable to a large deletion within the coding region of a previously characterized small subunit gene that we have called Hv.AGP.S.1. The plastidial AGPase activity in the mutant is unaffected. This shows that the cytosolic and plastidial small subunits of AGPase are encoded by separate genes. We purified the plastidial AGPase protein and, using amino acid sequence information, we identified the novel small subunit gene that encodes this protein. Studies of the Risø 16 mutant revealed the following. First, the reduced starch content of the mutant showed that a cytosolic AGPase is required to achieve the normal rate of starch synthesis. Second, the mutant makes both A- and B-type starch granules, showing that the cytosolic AGPase is not necessary for the synthesis of these two granule types. Third, analysis of the phylogenetic relationships between the various small subunit proteins both within and between species, suggest that the cytosolic AGPase single small subunit gene probably evolved from a leaf single small subunit gene.

Adenosine Diphosphate Glucose↗
PubMed2002

Export of acyl chains from plastids isolated from embryos of Brassica napus (L.).

We report the first measurements of the kinetics of transmembrane transport of acyl chains in plants. This was achieved by separating the period of in vitro synthesis of fatty acids from their export and by making use of acyl-CoA-binding protein (ACBP), which specifically binds long-chain acyl-CoAs. In the absence of added CoA but in the presence of ACBP, newly synthesised acyl chains accumulated as free fatty acids (FFAs) in plastids isolated from embryos of oilseed rape (Brassica napus L.). When CoA was added to plastids that had accumulated FFAs, the acyl chains were converted to acyl-CoAs that, in the presence of ACBP, were exported to the incubation medium. The rate of export was dependent on the CoA concentration and, at a saturating CoA concentration, was similar to the rate at which the fatty acids had been synthesised prior to CoA addition.

Acyl Coenzyme A↗
PubMed2002

Characterization of the genes encoding the cytosolic and plastidial forms of ADP-glucose pyrophosphorylase in wheat endosperm.

In most species, the synthesis of ADP-glucose (Glc) by the enzyme ADP-Glc pyrophosphorylase (AGPase) occurs entirely within the plastids in all tissues so far examined. However, in the endosperm of many, if not all grasses, a second form of AGPase synthesizes ADP-Glc outside the plastid, presumably in the cytosol. In this paper, we show that in the endosperm of wheat (Triticum aestivum), the cytosolic form accounts for most of the AGPase activity. Using a combination of molecular and biochemical approaches to identify the cytosolic and plastidial protein components of wheat endosperm AGPase we show that the large and small subunits of the cytosolic enzyme are encoded by genes previously thought to encode plastidial subunits, and that a gene, Ta.AGP.S.1, which encodes the small subunit of the cytosolic form of AGPase, also gives rise to a second transcript by the use of an alternate first exon. This second transcript encodes an AGPase small subunit with a transit peptide. However, we could not find a plastidial small subunit protein corresponding to this transcript. The protein sequence of the purified plastidial small subunit does not match precisely to that encoded by Ta.AGP.S.1 or to the predicted sequences of any other known gene from wheat or barley (Hordeum vulgare). Instead, the protein sequence is most similar to those of the plastidial small subunits from chickpea (Cicer arietinum) and maize (Zea mays) and rice (Oryza sativa) seeds. These data suggest that the gene encoding the major plastidial small subunit of AGPase in wheat endosperm has yet to be identified.

Amino Acid Sequence↗