Biomedical subjects

P A McDonnell

Publications and source records attributed to P A McDonnell.

18 recordsLinked to original sources

PubMed2003

Giardia duodenalis trophozoites isolated from a parrot (Cacatua galerita) colonize the small intestinal tracts of domestic kittens and lambs.

This study examines the ability of Giardia duodenalis trophozoites, isolated from a wild bird, to colonize the intestinal tracts of companion animals (kittens) and domestic ruminants (lambs). Trophozoites colonized the intestinal tracts of intraduodenally inoculated animals as demonstrated by increasing parasite burdens within the duodenum and jejunum and by fecal passage of cysts within 4 days post-inoculation. The pathogenesis of the trophozoites was further investigated in kittens. In these animals, infection significantly reduced jejunal brush border microvillous length and density, which resulted in a loss of overall epithelial brush border surface area. This injury was associated with the production of diarrhea in four of five infected kittens. These findings indicate that some bird species may carry G. duodenalis that represent a possible health threat to companion animals and livestock. Our results describe the first successful colonization of avian-derived G. duodenalis trophozoites in the small intestines of domestic kittens and lambs.

Animals↗

PubMed2001

National health expenditures, 1999.

The health care spending share of gross domestic product (GDP) remained steady between 1993 and 1999 as moderate-to-strong economic growth coincided with a rapid shift to managed care. This shift, along with decelerating growth in Medicare spending, appears to have generated a mostly one-time saving that lowered aggregate health expenditure growth.

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PubMed1999

Using affinity capillary electrophoresis to study the interaction of the extracellular binding domain of erythropoietin receptor with peptides.

We have shown that affinity capillary electrophoresis (ACE) can be utilized to screen peptides that bind to the extracellular binding domain of the erythropoietin receptor (EBP). The comparison of the cyclic peptides GGTYSCHFGPLTWVCKPQGG (EMP1) GGTYSCHFGPLTAVCKPQGG (EMP13), and LGRKYSCHFGPLTWVCQPAKKD (EMP37) with the linear peptides HFGPLTWV (EMP26) and FMRF as ACE buffer additives were investigated. When EMP1 and EMP37 were the buffer additives, an abrupt change in the electrophoretic mobility of EBP was observed in the electropherogram. When EMP13, EMP26, and FMRF were examined under identical ACE conditions as EMP1 and EMP37, no significant change in the electrophoretic mobility of EBP was observed. These results correlate well with previously reported IC50 competitive binding data; that is, EMP1 and EMP37 bind to EBP while EMP13 and EMP26 bind very weakly. These observations strongly infer that peptide.EBP dimerization were induced by EMP1, and EMP37 but not by EMP13, EMP26 or FMRF. This ACE method provides a rapid tool for the detection of small peptides or drugs that bind to EBP.

Amino Acid Sequence↗

PubMed1999

National health expenditures, 1998.

In 1998, national health care expenditures reached $1.1 trillion, an increase of 5.6 percent from the previous year. This marked the fifth consecutive year of spending growth under 6 percent. Underlying the stability of the overall growth, major changes began taking place within the Nation's health care system. Public payers felt the initial effects of the Balanced Budget Act of 1997 (BBA), and private payers experienced increased health care costs and increased premium growth.

Budgets↗

PubMed1998

Using capillary electrophoresis/frontal analysis to screen drugs interacting with human serum proteins.

We have used capillary electrophoresis in the frontal analysis mode (CE/FA) to determine the binding capacity of beta-adrenoceptor blocking drugs to individual serum proteins, serum protein mixtures and human serum. The free drug concentration was directly measured from the height of the frontal peak and used to calculate the bound drug concentration. From the bound drug concentration, the percentage of drug bound to the serum proteins alpha1-acid glycoprotein (AGP) and human serum albumin (HSA) was then determined. In addition to determining the percent of a drug bound to a protein, the drug-protein association constant (Ka) was determined for AGP binding to beta-blockers. The data-estimated association constants were consistent with literature values. The CE/FA studies on the beta-adrenoceptor blocking drugs and the serum proteins indicated that HSA, AGP, high density lipoprotein (HDL), and low density lipoprotein (LDL) were the main contributors to serum binding for this series of compounds. The serum-drug binding data sorted the beta-adrenoceptor blocking drugs into high and low binding categories. The protein mixture (AGP + HSA + HDL + LDL) resulted in dividing the beta-blockers into the same high/low rankings. The protein mixture (AGP + HSA + HDL + LDL) was amenable to automation, did not autoaggregate, and had constant concentrations for the proteins.

Adrenergic beta-Antagonists↗

PubMed1998

Virulent Avian Giardia duodenalis Pathogenic for Mice.

Early in 1995, a sulphur-crested cockatoo captured in the wild died along with several other cage mates, apparently of an overwhelming, acute infection of Giardia. Trophozoites isolated from the dead bird and established in traditional Giardia axenic medium were infective to mice and established chronic infections associated with weight gain impairment. Genetically and morphologically, the Giardia isolated from the bird belonged to the duodenalis group. Here, Jacqui Upcroft, Ann McDonnell and Peter Upcroft present data on pathogenic avian Giardia with he potential to contaminate watersheds and discuss the implications.

Journal Article↗

PubMed1998

Giardia infection in budgerigars.

Budgerigars (Melopsittacus undulatus) from two different breeding colonies were found to have Giardia infection. Light microscopy, scanning electron microscopy and in-vitro and in-vivo studies confirmed the species was G psittaci. Chicks were clinically affected and showed signs of retarded growth, dehydration and diarrhoea. The faeces of adult birds treated with metronidazole in drinking water were negative for Giardia 5 days after treatment. Megabacteria were also found in adult birds but were not treated. This study extends the known host range for Giardia in Australia to include budgerigars.

Animals↗

PubMed1998

National health expenditures, 1997.

In 1997 health spending in the United States increased just 4.8 percent to $1.1 trillion. As a share of gross domestic product (GDP), national health expenditures (NHE) absorbed 13.5 percent of the country's output in 1997--a share that has remained relatively constant for 5 years. Despite the relative stability in recent years, signs of changing trends are emerging.

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PubMed1997

Protein structure determination using a combination of comparative modeling and NMR spectroscopy. Application to the response regulator protein, Spo0F.

A practical combination of comparative modeling and NMR spectroscopy was used to generate a three-dimensional structure of the response regulator protein, Spo0F. The backbone structure obtained compares to the Spo0F Y13S mutant X-ray structure with an rmsd of 2.0 A. We provide results which suggest that structures obtained by this method are suitable for drug discovery. The results of the GRID and DOCK methods as applied to the model and X-ray structures of Spo0F are remarkably similar and tend to suggest the same design conclusions. This trend is illustrated by these same techniques applied to two experimentally derived structures of the analogous protein, CheY, which exhibit a pairwise rmsdBB on the same order as that found for the two Spo0F structures.

Amino Acid Sequence↗

PubMed1997

Lethal Giardia from a wild-caught sulphur-crested cockatoo (Cacatua galerita) established in vitro chronically infects mice.

An axenic culture of Giardia was established from a sample of infected intestine obtained following autopsy of a sulphur-crested cockatoo (Cacatua galerita). The cockatoo recently captured in the wild and with good muscle tone died along with several other cage mates, apparently of an overwhelming, acute infection of Giardia. Trophozoites which established in the traditional, axenic Giardia medium (TYI-S-33 with supplementary bile) were morphologically identical to G. duodenalis. When outbred Quackenbush Swiss neonatal mice were infected with trophozoites a chronic infection was established and parasites were still present at 38 days post-inoculation. Weight gain by infected mice was reduced by 20%, thus mimicking failure-to-thrive syndrome in children, and maximum parasite load was more than 3-fold higher in comparison with other G. duodenalis strains. Analysis of the electrophoretic karyotype, rDNA and hybridization studies together with Giemsa- and trichrome-stained samples, and scanning electron microscopy indicated that the bird-derived Giardia belonged to the duodenalis group. This is the first report of infection of mammals with Giardia isolated from a bird. These data may have potentially serious implications for contamination of watersheds and establishment of zoonotic infections.

Animals↗

PubMed1997

National health expenditures, 1996.

The national health expenditures (NHE) series presented in this report for 1960-96 provides a view of the economic history of health care in the United States through spending for health care services and the sources financing that care. In 1996 NHE topped $1 trillion. At the same time, spending grew at the slowest rate, 4.4 percent, ever recorded in the current series. For the first time, this article presents estimates of Medicare managed care payments by type of service, as well as nursing home and home health spending in hospital-based facilities.

Drug Prescriptions↗

PubMed1996

National health expenditures, 1994.

This article presents data on health care spending for the United States, covering expenditures for various types of medical services and products and their sources of funding from 1960 to 1994. Although these statistics for 1994 show the slowest growth in more than three decades, health spending continued to grow faster than the overall economy. The Federal Government continued to fund an increasing share of health care expenditures in 1994, offset by a falling share from out-of-pocket sources. Shares paid by State and local governments and by other private payers including private health insurance remained unchanged from 1993.

Ambulatory Care↗

PubMed1996

National health expenditures, 1995.

This article presents data on health care spending for the United States, covering expenditures for various types of medical services and products and their sources of funding from 1960 to 1995. In 1995, $988.5 billion was spent to purchase health care in the United States, up 5.5 percent from 1994. Growth in spending between 1993 and 1995 was the slowest in more than three decades, primarily because of slow growth in private health insurance and out-of-pocket spending. As a result, the share of health spending funded by private sources fell, reflecting the influence of increased enrollment in managed care plans.

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PubMed1996

Business, households, and government: health spending, 1994.

During the 1990s, growth in health care costs slowed considerably, helping to lessen the spending strain on business, government, and households. Although cost growth has slowed, the Federal Government continues to pay an ever-increasing share of the total health care bill. This article reviews important health care spending trends, and for the first time, provides separate estimates of the employer and employee share of the premium costs for employer-sponsored private health insurance. This article also highlights some of the emerging trends in the employer-sponsored insurance market, including managed care, cost-sharing, and employment shifts.

Data Collection↗

PubMed1994

National health spending trends, 1960-1993.

In 1993 the nation spent $884.2 billion on health care, a 7.8 percent increase from 1992. Although this spending growth was among the lowest rates of growth recorded since 1960, it is too soon to tell whether slower growth in health spending is a new trend or merely a temporary perturbation in the long-term trend. The portion of the economy devoted to health care increased from 13.6 percent in 1992 to 13.9 percent in 1993--a 0.3 percentage point increase that equaled the average rate of increase recorded since 1960. The federal government's share of the total health care bill rose between 1991 and 1993, the first significant change in the share of the nation's health care bill funded by the federal government since the early 1970s.

Capital Expenditures↗

PubMed1994

National health expenditures, 1993.

This article presents data on health care spending for the United States, covering expenditures for various types of medical services and products and their sources of funding from 1960 to 1993. Although these statistics show a slowing in the growth of health care expenditures over the past few years, spending continues to increase faster than the overall economy. The share of the Nation's health care bill funded by the Federal Government through the Medicaid and Medicare programs steadily increased from 1991 to 1993. This significant change in the share of health expenditures funded by the public sector has caused Federal health expenditures as a share of all Federal spending to increase dramatically.

Cost Allocation↗

PubMed1993

fd coat protein structure in membrane environments.

The membrane bound form of bacteriophage fd coat protein has a long hydrophobic membrane spanning helix and a shorter amphipathic helix in the plane of the bilayer. Residues near the N and C termini and in the turn connecting the two helices are mobile. The locations and orientations of the helical secondary structure elements and the protein backbone dynamics were characterized by combining results from multidimensional solution NMR experiments on protein samples in micelles and high resolution solid-state NMR experiments on protein samples in oriented and unoriented lipid bilayers. The coat protein is a monomer in micelles. The secondary structure of the membrane bound form of fd coat protein is very similar to that of the structural form found in the virus particles, since it is nearly all alpha helix. However, the membrane bound form of the protein differs from the structural form of the protein in virus particles in the arrangement of the secondary structure, since the membrane bound form of the protein has two distinct helical domains oriented perpendicular to each other and the structural form of the protein in the virus particles has a nearly continuous helix aligned approximately along the filament axis. In addition, there are substantial differences in the dynamics of residues in the bend between the two helices and near the C terminus, since they are mobile in the membrane bound form of the protein and not in the virus particles. Residues 1 to 5 at the N terminus are highly mobile and unstructured in both the membrane bound and structural forms of the coat protein.

Amides↗

PubMed1993

Business, households, and governments: health spending, 1991.

Governments have been thrust to the forefront of health care reform efforts as growth in government health care costs was faster than growth in all other sponsor sectors in 1991. In the business sector, real health care costs per worker have risen 65 times faster than real wages and salaries per worker during the past 26 years. Households continue to devote 5 percent of income after taxes to health care, the same percentage for the last 8 years. This article presents data supporting these findings, and an analysis of health care spending by each sponsor sector.

Commerce↗