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Biomedical subjects

B H Gray

Publications and source records attributed to B H Gray.

At least 37 records · Page 2Linked to original sources
PubMed1995

Sputum peroxidase activity correlates with the severity of lung disease in cystic fibrosis.

Patients with cystic fibrosis (CF) of the same age differ significantly in their degree of pulmonary disease. Based on preliminary observations, we postulated that the activity of myeloperoxidase would be significantly increased in patients with greater structural lung damage than in those with less lung damage. Acid extracts of weighed sputum samples were assayed for lactoferrin concentrations by ELISA. Activities of peroxidase, cathespsin G, and elastase (with and without proteinase 3) were determined by kinetic analysis using chromogenic substrates. The patients were divided into quartiles based on their Brasfield chest-radiograph score. Patients in the first quartile (least amount of structural lung abnormality) were compared to those in the fourth quartile. The concentration of lactoferrin, a specific (secondary) granule protein of neutrophils, did not differ between the two patient groups. However, the activities of the neutrophil primary granule proteins, peroxidase, elastase, and elastase plus proteinase 3, were significantly elevated in the group with the most structural lung abnormality. Sputum albumin concentration was used to estimate leakages of plasma proteins into the airways. Peroxidase activity, but not the activity of cathepsin G, of elastase, or of elastase plus proteinase 3, correlated significantly with albumin/g sputum in both quartile groups. To confirm the association of sputum peroxidase activity with differences in lung structure and to test its correlation with lung function, spirometry was performed in a second group of patients during the week prior to the time of sputum sampling. In this second group, increased sputum peroxidase activity was associated with worse Brasfield scores and with decreased percent-predicted forced expiratory volume in 1 sec.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1995

Peptide derivatives of three distinct lipopolysaccharide binding proteins inhibit lipopolysaccharide-induced tumor necrosis factor-alpha secretion in vitro.

BACKGROUND: Bactericidal permeability increasing protein (BPI), Limulus anti-lipopolysaccharide factor (LALF), and lipopolysaccharide binding protein (LBP) are three distinct proteins that bind to lipopolysaccharide (LPS). Intriguingly, binding of BPI and LALF to LPS results in neutralization of LPS activity, whereas the binding of LBP to LPS creates a complex that results in augmentation of LPS activity. Despite their different effector functions, we hypothesized that peptides based on the sequences of the proposed LPS-binding motif from each protein would neutralize LPS in vitro. METHODS: Three peptide sequences, each 27 amino acids in length, of the proposed LPS-binding motif of BPI (BG38), LALF (BG42), and LBP (BG43) were synthesized. These peptides were then tested for their: (1) ability to inhibit macrophage secretion of TNF-alpha after stimulation by LPS derived from Escherichia coli, Klebsiella pneumoniae, Pseudomonas aeruginosa, and Serratia marcescens; and (2) bactericidal activity against these same four gram-negative bacteria in vitro. RESULTS: Synthetic peptides BG38 (BPI-derived), BG42 (LALF-derived), and BG43 (LBP-derived) but not control peptide significantly inhibited LPS-induced tumor necrosis factor-alpha secretion by macrophages and mediated the lysis of gram-negative bacteria in vitro. In addition, preincubation of LPS with peptide BG38 mediated complete protection subsequent to lethal endotoxin challenge. CONCLUSIONS: These data demonstrate that small peptides derived from BPI, LALF, and LBP retained significant endotoxin-neutralizing and bactericidal activity against many different gram-negative bacteria in vitro. Identification of this conserved LPS-binding region within each protein may aid in the development of new immunomodulatory reagents for use as adjuvant therapy in the treatment of gram-negative bacterial sepsis.

Acute-Phase Proteins↗
PubMed1995

Medical sociology and health policy: where are the connections?

The attempt to assess the impact of medical sociology on health policy encounters operational difficulties regarding what should be counted. After reviewing these difficulties, we argue that there is potential interest among policymakers for sociological contributions to policy debates, but that policy impact has been limited by sociologists' ambivalence, academic career considerations, and by health research becoming a distinct field of research. Suggestions for increasing sociologists' policy impact include attending to policy relevance in both the design of studies and the dissemination of results and by sociologists' becoming more oriented to the field of health policy research.

Health Planning↗
PubMed1994

Bactericidal activity of synthetic peptides based on the structure of the 55-kilodalton bactericidal protein from human neutrophils.

Short (10- to 11-mer) hydrophilic peptides based on the structure of the 55-kDa bactericidal protein (BP55, B/PI, and CAP57) from human neutrophil granules were identified from the hydropathy plot of the 456-amino-acid sequence predicted from the nucleotide sequences of cDNA clones for BP55 and B/PI. Peptides corresponding to amino acid residues 90 to 99 (peptide #90-99), 86 to 99, or 90 to 102 of BP55 were bactericidal toward 5 x 10(6) Pseudomonas aeruginosa cells at 0.6 x 10(-5) to 1.5 x 10(-5) M and killed an Escherichia coli rough strain at 3 x 10(-5) M. The #90-99 peptide with a cysteine added at the amino terminus (C#90-99) was approximately 10 times more active than #90-99, killing P. aeruginosa at 1.5 x 10(-6) M. Peptides representing amino acid residues 27 to 37, 118 to 127, and 160 to 170 and the first 10 amino acids of the signal sequence for BP55 were not bactericidal. When coupled to either keyhole limpet hemocyanin or ovalbumin protein carriers through the thiol group, the C#90-99 peptide was not diminished on a molar basis in its capacity for killing of P. aeruginosa. Two other relatively hydrophilic peptides with an added amino-terminal cysteine, peptides C#227-236 and C#418-427, were not bactericidal at 1.2 x 10(-4) M or at 100 times the effective bactericidal concentration of C#90-99. The C#90-99 peptide killed E. coli at 1.5 x 10(-5) M, or at 10 times the concentration required to kill an equal number of P. aeruginosa cells. Although Pseudomonas cepacia and Staphylococcus aureus were resistent to killing by the parent BP55 molecule, they were susceptible to the C#90-99 and #90-99 peptides in the same concentration range as was E. coli. When all peptides were compared for the ability to neutralize E. coli O55:B5 endotoxin in a Limulus amoebocyte lysate assay, the C#227-236, C#418-427, and #160-170 peptides completely inhibited gelation at a 10(-4) M concentration. All other synthetic peptides, including bactericidal peptide #90-99 and its congeners, lacked endotoxin-neutralizing activity at the highest concentration tested (4.5 x 10(-4) M). A hybrid of the C#227-236 and #90-99 peptides (CHybrid) was identical to the C#227-236 peptide component in effectiveness for carrying out endotoxin neutralization and was fivefold better than the #90-99 peptide in its capacity for killing P. aeruginosa.

Amino Acid Sequence↗
PubMed1994

The proteinase-antiproteinase balance in alpha-1-proteinase inhibitor-deficient lung transplant recipients.

We examined the proteinase-antiproteinase balance in the bronchoalveolar lavage (BAL) fluid from alpha-1-proteinase inhibitor (alpha 1PI)-deficient lung transplant recipients to determine whether they would derive benefit from intravenous augmentation therapy with alpha 1PI. BAL fluid from 11 alpha 1PI-deficient lung transplant recipients and eight control subjects was assayed for free neutrophil elastase activity, immunoreactive alpha 1PI, and elastase inhibitory capacity. Samples were obtained during intervals of health and respiratory illness. BAL fluid from healthy alpha 1PI-deficient lung transplant recipients had minimal or unmeasurable free elastase activity, which was not different from that of control subjects. alpha 1PI concentrations in BAL fluid from alpha 1PI-deficient lung transplant recipients were reduced when compared with those of control subjects. Despite this observation, all but one alpha 1PI-deficient patient had the ability to inhibit exogenous elastase. During respiratory illness, however, three of seven alpha 1PI-deficient lung transplant recipients had measurable free elastase activity, which was inhibited ex vivo by addition of alpha 1PI. We conclude that alpha 1PI-deficient lung transplant recipients demonstrate free elastase activity in BAL fluid during severe lower respiratory tract inflammation, which is not present during health. Intravenous supplementation of alpha 1PI-deficient lung transplant recipients with exogenous alpha 1PI during respiratory tract inflammation may be indicated to inhibit elastase-mediated injury to the transplanted lung.

Adult↗
PubMed1993

Interaction of secretory leukocyte protease inhibitor with proteinase-3.

Secretory leukocyte protease inhibitor (SLPI) is a 12 kD nonglycosylated serine antiproteinase secreted by cells of mucosal surfaces. In human lung, SLPI is present in the respiratory epithelium. It is the major barrier to tissue destruction mediated by the polymorphonuclear leukocyte (PMN) serine proteinases, elastase and cathepsin G, within the upper respiratory tract. We have recently described a third PMN serine proteinase, proteinase-3, that like elastase causes lung matrix destruction and experimental emphysema. The current studies examine interactions between SLPI and proteinase-3. The results show that: (1) SLPI and its reactive-site variants have no or minimal inhibitory activity against proteinase-3; (2) native SLPI does not complex with proteinase-3; (3) proteinase-3 selectively degrades both native and oxidized SLPI; (4) the cleavage of SLPI by proteinase-3 occurs at the peptide bond COOH-terminal to Ala-16 in the NH2-terminal domain of SLPI.

Amino Acid Sequence↗
PubMed1992

Deep venous thrombosis and pulmonary embolism. The importance of heightened awareness.

Left untreated, deep venous thrombosis and pulmonary embolism have a high rate of mortality and long-term morbidity. Physicians therefore must maintain a high index of suspicion for these conditions. Accurate diagnosis is facilitated by knowing the most common sites of thrombus formation, the likelihood of propagation, which patients are at greatest risk, signs and symptoms, and which tests to order. Prompt administration of anticoagulants and, in some cases, thrombolytic agents can minimize the consequences of these diseases. Interruption of the inferior vena cava, thrombectomy, and thromboembolectomy are other treatment options.

Heparin↗
PubMed1992

The legislative battle over health services research.

Budget reconciliation legislation in 1989 created the new Agency for Health Care Policy and Research (AHCPR), which folded in the National Center for Health Services Research and Health Care Technology Assessment, among the law's other provisions. The creation of the new agency represented a shift in priorities toward outcomes and effectiveness research in medical practice and made explicit the federal government's role in developing practice guidelines. The new agency was born in the midst of an extraordinary bipartisan budget negotiation process in late 1989; its becoming linked to the contentious issue of physician payment reform nearly killed the new agency before it appeared. The narrative of political wrangling that resulted in the creation of AHCPR spans Capitol Hill, the White House, the agencies of the Department of Health and Human Services, and renowed health services researchers on either coast and in Washington, D.C.

Health Policy↗
PubMed1992

Why nonprofits? Hospitals and the future of American health care.

The future of the nonprofit hospital depends on its relationship to the for-profit and governmental sectors of our economy. A decade ago, the primary challenge came from the growing investor-owned hospital companies. Nonprofit hospitals' responses--both competitive and imitative--led to new challenges from government regarding tax-exempt status. The reasons underlying this challenge include the growing commercialism of health care, the nation's failure to deal directly with the problem of the uninsured, and the lack of a coherent theory of tax exemption. Although hospitals are likely to retain exemptions from federal taxation, challenges to local tax exemptions are likely to continue. Strategies that hospitals pursue for competitive purposes may undercut their legitimacy as tax-exempt institutions, but several groups are working to address the issue.

Charities↗
PubMed1992

Nonsurgical restoration of pulsatile arterial flow.

Percutaneous transluminal angioplasty is an established method of revascularization in a variety of arterial stenotic conditions. When applied to specific morphologic and clinical indications, it can be very effective. It appears to be the procedure of choice for focal stenotic lesions of the iliac and femoropopliteal system. Its role in infrapopliteal atherosclerotic disease is less certain, but more optimistic, with recent reports. New methods for preventing restenosis and abrupt closure are currently being developed, and they appear to be promising as adjunctive therapy with mechanical catheter-directed intervention. The future of these adjunctive agents will likely improve the outcome and reduce the immediate failure rates of angioplasty. Other modalities, including thermal laser angioplasty and atherectomy, also appear to have a promising future. These methods, coupled with better endoluminal guidance, such as ultrasound, will help guide the interventional procedure more precisely and hopefully broaden the application and improve the outcome.

Angiography↗
PubMed1992

World blindness and the medical profession: conflicting medical cultures and the ethical dilemmas of helping.

This is an account of a thwarted humanitarian effort and the strategic and ethical issues that is raised. Between 14 and 17 million people in the world are blind with cataract, a condition readily corrected by surgery. In 1989 a proposal was developed to attack this problem by supplying volunteer ophthalmologists to the world's leading private voluntary organizations that carry out programs in less developed countries. The proposal was rejected. This article describes the proposal and the issues on which it foundered: cost effectiveness, appropriate technology, changing ideologies of assistance, and conflict between the cultures of medicine and public health. The account illustrates the far-flung consequences of technological change in medicine, as well as the practical and ethical questions facing organizations that carry out overseas assistance programs.

Altruism↗
PubMed1991

Characterization of proteinase-3 (PR-3), a neutrophil serine proteinase. Structural and functional properties.

Proteinase 3 (PR-3) is a human polymorphonuclear leukocyte (PMNL) serine proteinase that degrades elastin in vitro and causes emphysema when administered by tracheal insufflation to hamsters (Kao, R. C., Wehner, N. G., Skubitz, K. M., Gray, B. H., and Hoidal, J. R. (1988) J. Clin. Invest. 82, 1963-1973). We have determined the primary structure of several PR-3 peptides and have analyzed catalytic properties of the enzyme. The enzyme has considerable amino acid sequence homology with two other well characterized PMNL neutral serine proteinases, elastase and cathepsin G. Furthermore, the NH2-terminal amino acid sequence of PR-3 is identical to that of the target antigen of the anti-neutrophil cytoplasmic autoantibodies associated with Wegener's granulomatosis. PR-3 degrades a variety of matrix proteins including fibronectin, laminin, vitronectin, and collagen type IV. It shows no or minimal activity against interstitial collagens types I and III, respectively. The analysis of peptides generated by PR-3 digestion of insulin chains and the activity profile against a panel of chromogenic synthetic peptide substrates show that PR-3 prefers small aliphatic amino acids (alanine, serine, and valine) at the P1 site. The elastase-like specificity of PR-3 is consistent with its striking sequence homology to elastase at substrate binding sites. PR-3 is inhibited by alpha 1-proteinase inhibitor (ka = 8.1 x 10(6) M-1 S-1; delay time = 25 ms) and alpha 2-macroglobulin (ka = 1.1 x 10(7) M-1 S-1; delay time = 114 ms) but not by alpha 1-anti-chymotrypsin. In contrast to elastase and cathepsin G, PR-3 is not inhibited by secretory leukoprotease inhibitor and is weakly inhibited by eglin c. Thus, PR-3 is distinct from the other PMNL proteinases.

Amino Acid Sequence↗
PubMed1991

Comparison of granule proteins from human polymorphonuclear leukocytes which are bactericidal toward Pseudomonas aeruginosa.

Killing of Pseudomonas aeruginosa by a 55-kDa bactericidal protein (BP 55), a 30-kDa protein (BP 30), cathepsin G, elastase, and proteinase 3 has been compared. P. aeruginosa was resistant to killing by elastase and proteinase 3. BP 55 at a 50% lethal dose (LD50) of 0.23 micrograms of protein per 5 x 10(6) bacteria per ml killed P. aeruginosa and was far more active than BP 30 and cathepsin G. The LD50s of BP 30 and cathepsin G were 16.9 and 28.3 micrograms of protein per 5 x 10(6) bacteria per ml, respectively. Preincubation of BP 55 or BP 30 with lipopolysaccharide (LPS) from P. aeruginosa inhibited bactericidal activity. The N-terminal amino acid sequence of BP 55 and BP 30 revealed no relationship between the two proteins. However, a monoclonal antibody (AHN-15) reacted with both proteins by Western immunoblot. The bactericidal activity of cathepsin G toward P. aeruginosa appeared to be dependent on the availability of the active site of the enzyme; bactericidal activity was inhibited by phenylmethylsulfonyl fluoride (PMSF) and by the specific cathepsin G inhibitor, Z-Gly-Leu-Phe-CH2Cl. The enzyme and bactericidal activities of cathepsin G were also inhibited by LPS from P. aeruginosa. LPS from P. aeruginosa was shown to be a competitive inhibitor of the enzyme activity of cathepsin G. Elastase enzyme activity was also inhibited noncompetitively by LPS, but the enzyme was not bactericidal. We have concluded that all three bactericidal proteins (BP 55, BP 30, and cathepsin G) may bind to the LPS of the outer membrane of P. aeruginosa. It appears that the enzyme active site must be available for cathepsin G to kill P. aeruginosa and that the active site may be involved in the binding of cathepsin G to P. aeruginosa.

Amino Acid Sequence↗
PubMed1991

Pseudomonas aeruginosa variants isolated from patients with cystic fibrosis are killed by a bactericidal protein from human polymorphonuclear leukocytes.

The susceptibility of paired mucoid and nonmucoid variants of Pseudomonas aeruginosa isolated from 13 patients with cystic fibrosis (CF) to killing by a 55,000-Da bactericidal protein (BP55) from human polymorphonuclear leukocytes was studied. Mucoid and nonmucoid variants were equally sensitive to killing by BP55 at both pH 5.6 and pH 7.2. Eleven of the isolates were resistant to the bactericidal activity of 10% normal human serum but were as sensitive as the serum-sensitive isolates to BP55. Similarly, the 15 isolates with lipopolysaccharides (LPS) containing O-polysaccharide side chains (smooth LPS) were as sensitive to BP55 as those isolates with rough LPS.P. aeruginosa isolates from patients in poor clinical condition were more likely to have LPS of the smooth type and to be resistant to killing by 10% human serum than the isolates from patients in good clinical condition. We have concluded that the susceptibility of the P. aeruginosa isolates from patients with CF to killing by BP55 does not correlate with mucoid or nonmucoid variations, with the presence or absence of smooth LPS, or with the sensitivity or resistance to killing by normal human serum.

Adolescent↗