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T F Murphy

Publications and source records attributed to T F Murphy.

17 recordsLinked to original sources
PubMed1992

Recurrent otitis media with non-typable Haemophilus influenzae: the role of serum bactericidal antibody.

The effect of serum bactericidal antibody on colonization with non-typable Haemophilus influenzae (NTHI) was studied in 26 children. Serum bactericidal antibody did not prevent colonization with NTHI in the nasopharynx. Antibody was present in 53% before, 91% during and 100% after documented colonization of the nasopharynx with NTHI. In addition, 5 children with recurrent otitis media with effusion (OME) due to NTHI were observed for bactericidal serum antibody during a 4-year period. Bactericidal antibody against the causative NTHI strain was not detected in the acute sera of any patient during each episode, but was observed in the convalescent sera of all of the patients. The bactericidal antibody in the convalescent serum did not appear to be protective against colonization and recurrence of disease by a different heterologous strain of NTHI. However, bactericidal antibody was augmented in some cases by a heterologous infection with NTHI. We confirmed the emergence of new strains of NTHI with DNA fingerprinting and outer membrane protein (OMP) analysis. The data suggest that the immune response to NTHI in OME is usually strain-specific, and furthermore, the results demonstrate that strain-specific bactericidal antibody does not prevent colonization in the nasopharynx with the homologous or heterologous bacterial strains. In general, bactericidal antibody is not cross-protective against heterologous strains of NTHI causing a second or third episode of otitis media with NTHI.

Antibodies, Bacterial↗
PubMed1992

Outer membrane protein P6 of Haemophilus influenzae binds to its own gene.

Outer membrane protein P6 is an important antigen expressed on the surface of all strains of Haemophilus influenzae. The predicted amino acid sequence of P6 contains a region of alpha helices that shares sequence identity with a family of helix-turn-helix DNA-binding proteins. A search for sequence-specific binding sites that resemble an operator region within the gene revealed a sequence with striking homology to the consensus operator sequence for lambda Cro and repressor. To test the hypothesis that P6 binds its own gene, purified P6 on nitrocellulose was probed with plasmid DNA containing the P6 gene. P6 bound the P6 gene in this Southwestern blot assay. To further test the observation, gel shift analysis was performed. Gel shift assays using a P6-specific monoclonal antibody demonstrated that P6 in crude cell extracts binds to the region of the gene containing the putative binding site. Competition with a synthetic oligonucleotide corresponding to the putative binding site inhibited binding of P6 to the P6 gene on nitrocellulose and in the gel shift assay. In addition, this oligonucleotide bound directly to P6 on nitrocellulose. Finally, DNase footprinting confirmed that P6 bound specifically to the same region of the P6 gene. These results indicate that P6 binds to a sequence-specific site within its own gene, suggesting that P6 regulates its own expression. This represents the first example of a Gram-negative outer membrane protein binding to its own gene and has potentially important implications as a mechanism for regulation of expression of outer membrane antigens.

Amino Acid Sequence↗
PubMed1992

Molecular analysis of the P2 porin protein of nontypeable Haemophilus influenzae.

The P2 porin protein is the most abundant outer membrane protein (OMP) of nontypeable Haemophilus influenzae (NTHI) and shows extensive antigenic heterogeneity among strains. To study the molecular basis of this heterogeneity, the DNA sequences of the genes encoding the P2 proteins of three unrelated strains of NTHI were determined, and restriction fragment length polymorphisms around the P2 genes of 35 strains were analyzed. The deduced amino acid sequences of the P2 genes from the three strains of NTHI revealed four major (12 to 35 amino acids long) and several smaller (2 to 7 amino acids) hypervariable regions in each protein. The major variations occurred in identical portions of the genes, and these regions showed a high antigenic index and surface exposure probability in computer modeling analysis. Differences in the molecular mass of the P2 protein correlate with differences in the size of the variable region in each strain. Oligonucleotide primers suitable for amplification of the P2 genes by polymerase chain reaction were developed. Restriction fragment length polymorphism analysis showed marked heterogeneity in and around the ompP2 locus of 35 NTHI strains. These results contrast with the high degree of conservation of the P2 genes in H. influenzae type b strains. We conclude that the molecular mass and antigenic heterogeneity of the P2 molecule of NTHI is due to variations in gene sequence that are clustered primarily in four large hypervariable regions of the gene.

Amino Acid Sequence↗
PubMed1992

Characterization of an antigenically conserved heat-modifiable major outer membrane protein of Branhamella catarrhalis.

Branhamella catarrhalis is a common cause of otitis media in children and of respiratory infections in adults with chronic bronchitis. Little is known about the antigenic structure of the outer membrane proteins (OMPs). In this study, two murine monoclonal antibodies, 7D6 and 5E8, were developed and used to characterize the major heat-modifiable OMP (OMP C/D) of B. catarrhalis. Immunoblot assays indicated that OMP C/D is heat modifiable, having a molecular mass of 55 kDa at room temperature and a mass of 60 kDa when heated under reducing conditions. Expression of the epitopes is independent of growth phase and growth media. Both epitopes are present in 51 of 51 strains of B. catarrhalis tested and are highly specific for Branhamella strains, being absent from a variety of other gram-negative species. Antibody 5E8 recognizes an epitope which is expressed on the surface of the intact bacterium. We conclude that OMP C/D is a major, heat-modifiable OMP antigen that expresses at least one stable, conserved epitope on the surface of B. catarrhalis. Future studies should focus on the role of OMP C/D in pathogenesis and on its potential role as a vaccine antigen.

Animals↗
PubMed1992

Neonatal, urogenital isolates of biotype 4 nontypeable Haemophilus influenzae express a variant P6 outer membrane protein molecule.

The P6 outer membrane protein is a highly conserved molecule which is present on the surface of all strains of Haemophilus influenzae. Sixty strains of nontypeable H. influenzae which caused invasive disease or colonized the female urogenital tract were studied with monoclonal antibodies 7F3 and 4G4, which recognize different surface-exposed epitopes on the P6 molecule. All 60 strains expressed the epitope recognized by 4G4, whereas 47 of 60 strains expressed the epitope recognized by antibody 7F3. The 7F3-nonreactive strains were all biotype 4 and were recovered from the blood of neonates or postpartum women or from the female urogenital tract. The P6 genes from two 7F3-nonreactive strains were cloned, and the nucleotide sequences were determined. Analysis of amino acid sequences, immunoassays with synthetic peptides, and site-directed mutation of the P6 gene indicate that the epitope recognized by antibody 7F3 is conformational and that the sequence Asp-Ile-Thr is critical in maintaining the conformation of the epitope. We conclude that the unusually virulent clone family of biotype 4 strains of nontypeable H. influenzae express a variant P6 molecule which has an alteration in a highly conserved surface-exposed epitope.

Antibodies, Monoclonal↗
PubMed1992

Freud and sexual reorientation therapy.

Contrary to certain psychoanalytic interpretations, Freud himself generally resisted the possibility or desirability of sexual reorientation therapy. Yet his understanding of the origins and nature of homoeroticism does not suggest that conversion therapy is impossible. Although he did not believe homoeroticism to be an inherent impediment to human accomplishment and fulfillment neither did he see it as having the full value of heteroeroticism. For these reasons he did not altogether rule out the desirability or possibility of conversion therapy for some individuals even if he did not believe that it could be psychoanalysis alone that could redirect sexual orientation.

Female↗
PubMed1992

Hemorrhagic shock inhibits lipopolysaccharide-induced myelopoiesis in both germ-free and conventional rats.

BACKGROUND: Bacterial translocation has been implicated in the alteration of the immune response after shock and trauma. This study examined the effect of bacterial translocation on myelopoiesis after hemorrhagic shock in germ-free and conventional rats. METHODS: Awake, unrestrained germ-free and conventional rats were bled to a mean arterial pressure of 30 mm Hg until the animal required infusion of 10% of the shed blood. Rats were resuscitated with shed blood and crystalloid. Sham rats were catheterized but not bled. Twenty-four hours after shock or sham, rats were administered lipopolysaccharide 100 micrograms or saline intraperitoneally. Twenty-four hours later, bone marrow cells were cultured for growth of granulocyte-macrophage colony-stimulating factor (CFU-GM). RESULTS: Lipopolysaccharide increased the number of CFU-GM/femur in sham germ-free rats (801 +/- 129 versus 455 +/- 110; p less than 0.05) and conventional rats (1458 +/- 200 versus 492 +/- 59; p less than 0.05) compared with saline-treated rats. In contrast, hemorrhagic shock inhibited lipopolysaccharide-induced CFU-GM growth in both germ-free and conventional rats. Shock, itself, was a stimulus for CFU-GM growth in germ-free but not conventional rats. Bone marrow white blood cell counts were unaffected by shock, lipopolysaccharide administration, or the germ-free state. CONCLUSIONS: Hemorrhagic shock inhibited lipopolysaccharide-induced CFU-GM proliferation independent of the germ-bearing status of the rat, and bacterial translocation exerted no influence on myelopoietic dysfunction after hemorrhagic shock.

Animals↗
PubMed1992

Intracranial and extracranial complications of acute mastoiditis: evaluation with computed tomography.

The incidence of acute mastoiditis has decreased significantly because we can effectively treat otitis media with oral antibiotics. Inadequate or delayed treatment of otitis predisposes to the development of mastoiditis and more serious, life-threatening complications. Extension of the infectious process beyond the mastoid system can lead to a variety of intracranial and extracranial complications including meningitis, epidural and intracerebral abscesses, vascular thrombosis, osteomyelitis, and abscesses deep within the neck. Signs of clinical deterioration in a patient with otitis media should indicate to the general practitioner that a more serious condition is evolving and surgical intervention may be necessary. Computed tomography is considered the imaging modality of choice for patients with acute mastoiditis because it can define clearly the regional anatomy and provide important diagnostic information.

Abscess↗
PubMed1991

Strain-specific and immunodominant surface epitopes of the P2 porin protein of nontypeable Haemophilus influenzae.

The P2 porin protein is the major outer membrane protein of nontypeable Haemophilus influenzae. Five monoclonal antibodies to P2 of four strains of nontypeable H. influenzae were developed by immunizing mice with whole bacterial cells. All five antibodies recognized epitopes on P2 in immunoblot assays of whole organism lysates, purified outer membrane, and purified P2. Competitive enzyme-linked immunosorbent assays and immunoblot assays of cyanogen bromide-digested P2 showed that two antibodies to the P2 protein of strain 1479 recognized different epitopes on the molecule. Immunofluorescence and immunoelectron microscopy demonstrated that each of the five antibodies recognized epitopes that were abundantly expressed on the bacterial surface. Analysis of 120 H. influenzae strains indicated that three of the five antibodies were reactive exclusively with the homologous strain. The remaining two antibodies were reactive with less than 3% of the strains. These studies indicate that the P2 protein expresses a highly strain-specific and immunodominant epitope on the bacterial surface. The expression of strain-specific and immunodominant epitopes on the bacterial surface may represent a mechanism by which the bacterium induces antibodies that will protect against recurrent infection by the homologous strain but will not protect against infection by heterologous strains.

Animals↗
PubMed1991

Molecular conservation of the P6 outer membrane protein among strains of Haemophilus influenzae: analysis of antigenic determinants, gene sequences, and restriction fragment length polymorphisms.

Infections caused by Haemophilus influenzae are a major worldwide health problem. In particular, nontypeable strains of H. influenzae are a common cause of otitis media in infants and children. A vaccine to prevent these infections would result in the prevention of substantial morbidity and cost savings. A problem in identifying an appropriate vaccine antigen has been the enormous antigenic heterogeneity among nontypeable strains of H. influenzae. The present study was undertaken to characterize the conservation of the P6 outer membrane protein (approximately 16,000 daltons) among strains of H. influenzae. A total of 20 type b strains and 20 nontypeable strains of diverse geographic and clinical origins was studied. Three approaches were taken. (i) Antigenic determinants recognized by monoclonal and polyclonal antibodies were present on P6 in all 40 strains tested. The molecular weight of P6 was identical in all strains. (ii) Comparison of the DNA sequences of the P6 genes from three epidemiologically and serologically unrelated strains demonstrated 100% homology at the amino acid level and 97 to 99% homology at the nucleotide level. (iii) Restriction fragment length polymorphism analysis demonstrated that the P6 gene and flanking sequences were highly conserved among all strains. These three independent series of experiments indicated that the P6 protein is highly conserved among strains of H. influenzae. P6 should receive serious consideration for inclusion in a vaccine to prevent infections caused by nontypeable H. influenzae.

Amino Acid Sequence↗
PubMed1990

Studies of the outer membrane proteins of Branhamella catarrhalis.

PURPOSE: Branhamella catarrhalis has emerged as an important human pathogen in the past several years. Therefore, studies of the outer membrane have been undertaken in order to identify virulence factors and begin to understand the immune response to infection. MATERIALS AND METHODS: The outer membrane of B. catarrhalis has been purified by sucrose density centrifugation. The outer membrane proteins (OMPs) of 50 strains from diverse sources were isolated by simpler methods and studied by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. Experiments were designed to identify OMPs that express determinants on the surface of the intact bacterium. RESULTS: Eight major OMPs have been identified (OMPs A through H). The OMP patterns from diverse strains were strikingly similar. OMP E (approximately 56,000 daltons) and OMP G (approximately 28,000 daltons) have determinants that are surface-exposed and these determinants are shared among a majority of strains of B. catarrhalis. CONCLUSION: These observations have important implications with regard to the immune response to infection and future vaccine development.

Bacterial Outer Membrane Proteins↗
PubMed1978

Bacteremia in 28 ambulatory children: relationship to pneumonitis and meningitis.

Bacteremia with known pathogens was documented in 28 acutely ill, febrile outpatients during a 29-month period. All of the children were previously healthy and were initially managed as outpatients. Eight patients presented with no identifiable focus of infection. Twenty patients had either otitis media or pneumonitis. An association between otitis media and bacteremia with H. influenzae type b was noted in 5 patients. Bacterial meningitis occurred subsequently in 7 patients (25%); 1 death occurred in this group. The blood culture, as an outpatient procedure, was helpful in establishing a bacterial etiology in selected children with either high fever (with or without otitis media), febrile seizures, or pneumonia. In addition, the positive blood culture was a vital aid in identifying the young child at risk for meningitis.

Ambulatory Care↗