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Biomedical subjects

H R Hill

Publications and source records attributed to H R Hill.

At least 19 recordsLinked to original sources
PubMed1999

Comparison of capillary zone and immunosubtraction with agarose gel and immunofixation electrophoresis for detecting and identifying monoclonal gammopathies.

Capillary zone electrophoresis (CZE) and immuno-subtraction electrophoresis (ISE) were evaluated for ability to detect and immunotype monoclonal proteins, compared with agarose gel electrophoresis (AGE) and immunofixation electrophoresis (IFE), respectively. Six hundred seventeen serum samples were analyzed with CZE and AGE to determine sensitivity and specificity in detecting IFE-confirmed monoclonal gammopathies. Both techniques detected all monoclonal spikes due to IgM (n = 8), IgG (n = 38), and free light chains (n = 3). Agarose gel electrophoresis, however, detected only 11 of 14 (79%) IgA monoclonal spikes detected with CZE. In a second study, 78 serum samples, 48 of which had a monoclonal gammopathy confirmed with IFE, were evaluated with ISE. Only 60% to 75% of the monoclonal gammopathies were correctly immunotyped with ISE by 4 readers blinded to the IFE immunotype. Thus CZE was more sensitive than AGE in detecting low concentrations of monoclonal proteins, but ISE is less accurate than IFE in determining the immunotype of the monoclonal gammopathy.

Autoanalysis↗
PubMed1999

Comparison of three different methods for measuring classical pathway complement activity.

The complement system plays an important role in host defense against infection and in most inflammatory processes. The standard 50% hemolytic complement (CH50) assay is the most commonly used method of screening patient sera for functional activity of the classical complement pathway. Our objective in this study was to compare two newer methods (the enzyme immunoassay and the liposome immunoassay) to a commercial CH50 assay for measuring total classical complement activity. We conclude that both newer methods compare well with a CH50 assay and are equally sensitive in screening routine clinical sera.

Adult↗
PubMed1999

Heterophile antibodies to bovine and caprine proteins causing false-positive human immunodeficiency virus type 1 and other enzyme-linked immunosorbent assay results.

Heterophile antibodies are a well-recognized cause of erroneous results in immunoassays. We describe here a 22-month-old child with heterophile antibodies reactive with bovine serum albumin and caprine proteins causing false-positive results to human immunodeficiency virus type 1 and other infectious serology testing.

Animals↗
PubMed1998

Comparison of an inhalant allergy immunoassay with allergen specific IgE determinations in human serum.

The diagnosis of inhalant allergy can be elusive, with symptoms resembling viral or bacterial infection, as well as immunologic deficiency. In this study an inhalant allergy immunoassay was investigated as a possible screen to rule in or out respiratory inhalant allergy in patients with allergic-type symptoms. The results of this screen were compared in 192 serum specimens submitted to our laboratory for specific IgE allergy testing and 73 blood bank samples. When the discrepant results of the inhalant allergy immunoassay were resolved by Western blot, a final sensitivity of 94.7% and specificity of 97.5% was calculated. We have found this inhalant allergy immunoassay to be an effective screen for detecting inhalant allergies, and believe it to be a useful tool for the primary care physician or non-allergist trying to differentiate inhalant allergens from chronic sinusitis or other causes of sinopulmonary congestion.

Allergens↗
PubMed1998

The face of Job.

We evaluated facial features in 9 patients from 7 kindreds with Job syndrome. Consistent features included prominent forehead with deep-set eyes, increased width of the nose, a full lower lip, and thickening of the nose and ears. The mean alar width (Z score = +3.9) and outer canthal distance (Z score = +2.2) were significantly increased. A recognizable face of Job syndrome exists.

Adolescent↗
PubMed1998

The effect of lactic acid on mononuclear cell secretion of proinflammatory cytokines in response to group B streptococci.

This study found that lactate alone had a stimulatory effect (207.1 +/- 16.3%; P = .001) on tumor necrosis factor (TNF)-alpha production by human mononuclear cells with the most profound secretion being at pathologic concentrations of 4-8 mM lactate. Furthermore, exposure of these mononuclear cells to group B streptococci (GBS, 10(5) cfu) resulted in TNF-alpha production of up to 621.1 +/- 42% of control; the combination of lactic acid and GBS increased TNF-alpha production up to 1019.3 +/- 16.1% (P = .001). The combination of GBS and lactate also enhanced the secretion of interleukin (IL)-1beta and IL-6. Lactate in pathologic concentrations, therefore, likely enhances the secretion of these inflammatory mediators and contributes to septic shock and meningitis caused by GBS.

Cells, Cultured↗
PubMed1997

Analysis of phage MS2 coat protein mutants expressed from a reconstituted phagemid reveals that proline 78 is essential for viral infectivity.

A full-length cDNA copy of the RNA genome of bacteriophage MS2 was assembled by the in-frame ligation of the central portion of the genome into a plasmid containing the 5' and 3' ends. Upon transformation of the ligation reaction into Escherichia coli, infectious phage particles were released into the medium. The plaquing ability of the phage produced from the cDNA construct was assessed against various bacterial strains confirming that the bacteriophage produced were male-specific. Sensitivity to RNase in agar overlay was used to confirm that the phage contained RNA. In addition, the phage were unable to infect piliated cells overexpressing MS2 coat protein, a resistance conferred by the binding of recombinant coat protein to the infecting strand of RNA at the replicase initiation region, thus preventing translation of the replicase gene. The phage capsids were visualised after negative staining by transmission electron microscopy, and appeared as spherical particles of approximately 25 nm diameter. The capsid proteins were examined by Western blotting, confirming the presence of a single protein of approximately 14 kDa, which bound anti-MS2 coat protein antibodies. The genomic RNA from single plaques was analysed by reverse transcription-PCR and the presence of the MS2 coat protein gene confirmed by DNA sequencing. The production of replicative MS2 phage from cDNA fragments was used to assess the viability of MS2 coat protein mutants, which had previously been shown to assemble into T = 3 capsid-like particles when expressed in vivo from a bacterial vector. The E76D mutation did not appear to affect phage viability, whilst replacement of the completely conserved P78 residue with asparagine abolished the production of infectious particles, suggesting that P78 may be involved in interactions with the phage maturation protein.

Base Sequence↗
PubMed1997

Detection of Epstein-Barr viral DNA in serum using rapid-cycle PCR.

Our study describes the comparison of a rapid nested PCR assay to standard serology techniques for the detection of Epstein-Barr virus (EBV) in serum. The sera of 81 patients with suspected EBV infection were analyzed; 54 were positive for one or more of the standard serology markers, i.e., IgM viral capsid antigen (VCA), IgG-VCA, Epstein-Barr nuclear antigen 1 (EBNA-1), and early antigen (EA), and 27 were negative for all serology markers. The sera from 15 normal healthy blood donors were also included. No EBV DNA was detected in any of the 15 blood donor samples or in any of the 27 samples with negative serology results. Eleven samples (20%) of the 54 with positive EBV serology results were positive for EBV DNA. Of these samples, 9 were EBV IgM-VCA positive and anti-EBNA negative, suggesting acute infection. One of the 11 samples had high titers of IgM-VCA, IgG-VCA, anti-EBNA, and anti-EA. The last of the 11 samples was from a patient with acute infectious mononucleosis without sufficient sample volume for EBV serology testing. Seventeen of the total 96 samples from the study were IgM-VCA positive and anti-EBNA negative and 9 of these 17 samples (53%) tested positive for EBV DNA. These data suggest that the detection of EBV DNA by PCR in serum may be a useful indicator of active infection rather than latent virus.

Antibodies, Viral↗
PubMed1997

Regulation of decidual cell chemokine production by group B streptococci and purified bacterial cell wall components.

OBJECTIVE: Our purpose was to determine whether cultured human decidual cells produce chemokines in response to different strains of group B streptococci and purified bacterial cell wall components. STUDY DESIGN: Human decidual cells were cultured from term placentas by standard techniques. Different strains of group B streptococci were isolated from neonates with early-onset group B streptococci sepsis. Confluent cell monolayers were incubated with these different strains of group B streptococci and various concentrations of purified bacterial cell wall components (including lipoteichoic acid, sialic acid, lipopolysaccharide, and lipid A) for 16 hours at 37 degrees C. Culture supernatants were collected and assayed for macrophage inflammatory protein-1 alpha and interleukin-8. Statistical analysis was by analysis of variance. RESULTS: We found that cultured human decidual cells produced significant amounts of the two chemokines macrophage inflammatory protein-1 alpha and interleukin-8 in a strain-specific fashion to the various different strains of group B streptococci tested, from 215% to 421% over baseline production (p < 0.05 by analysis of variance). Also, we found that incubation of decidual cells with various concentrations of lipoteichoic acid, sialic acid, lipopolysaccharide, and lipid A resulted in significant concentration-dependent increases in decidual cell macrophage inflammatory protein-1 alpha and interleukin-8 production (p < 0.05.) CONCLUSIONS: Decidual cells produced significant amounts of the chemokines macrophage inflammatory protein-1 alpha and interleukin-8 in response to intact group B streptococci in a strain-specific fashion and in response to various concentrations of different bacterial cell wall components. Because chemokines are important mediators signaling migration of different immune effector cells into areas of inflammation, we suggest that decidual cell chemokine production in response to bacteria and bacterial cell wall components may be a key early event in the pathogenesis of infection-associated preterm labor.

Analysis of Variance↗
PubMed1997

A role for C5 and C5a-ase in the acute neutrophil response to group B streptococcal infections.

Congenic C5-deficient and C5-sufficient mice were infected with group B streptococci (GBS) to determine if the polymorphonuclear leukocyte (PMNL) chemoattractant C5a contributes to PMNL recruitment in GBS infection and if GBS C5a-ase reduces C5a-induced PMNL recruitment in vivo. PMNL accumulation was greater in the peritoneum and air spaces of C5-sufficient mice than in C5-deficient mice. Administration of human C5 to C5-deficient mice caused a significant increase in PMNL recruitment following infection with C5a-ase-negative GBS. GBS C5a-ase did not reduce PMNL accumulation in C5-sufficient mice but reduced PMNL recruitment in C5-deficient mice reconstituted with human C5. These data indicate that C5a is important for rapid PMNL recruitment to sites of GBS infection and that GBS C5a-ase inactivates human, but not murine, C5a in vivo. Reduction of the acute inflammatory response by C5a-ase likely contributes to GBS virulence in human neonates.

Adhesins, Bacterial↗
PubMed1997

Immunologic response to Bartonella henselae as determined by enzyme immunoassay and Western blot analysis.

Bartonella henselae is now regarded as the etiologic agent of cat-scratch disease and a cause of bacillary angiomatosis. We examined the human immune response to Bartonella henselae infection using a newly developed enzyme immunoassay (EIA) and a Western blot procedure using outer-membrane proteins. The EIA showed 98.6% and 91.4% agreement with an indirect fluorescence method (IFA) for detection of IgM and IgG antibodies, respectively. By using Western blot analysis, reactivity to an 8-kd band showed significant correlation with positive results by the IgM IFA and EIA. In contrast, reactivity to 209-, 208.5-, 208-, 116-, and 80-kd bands was identified only in positive IgG IFA serum samples. The EIA and Western blot should be useful tests in determining the antibody response to B. henselae infection and may also be important in determining the critical epitopes in the host-parasite interaction of this organism.

Adolescent↗
PubMed1997

Immunologic and clinical correlations in rheumatic fever and rheumatic heart disease.

The intimate relationship of Streptococcus pyogenes and rheumatic fever is well-established, but the precise pathogenesis of rheumatic fever and rheumatic heart disease continues to elude intense investigative efforts by students of the disease worldwide. Technologic advances in molecular biology, not thought possible two decades ago, have given additional insight into the immunologic aspects of the disease. On the clinical side echocardiography has proved to be a marvelous, non-invasive technique to evaluate cardiac anatomy and function. We are now able to gain a closer correlation of the clinical presentation and the autoimmune response. The increased understanding acquired both from the "bench" and the "bedside" are making this perplexing disease somewhat less mysterious. We seem tantalizingly close to grasping a complete understanding of the pathogenesis of rheumatic fever and rheumatic heart disease.

Antibodies↗
PubMed1997

Immunoglobulin A antibodies to Helicobacter pylori.

Serological testing for immunoglobulin G (IgG) antibodies to Helicobacter pylori has proven useful in supporting the diagnosis of infection with this organism, but the clinical value of IgA antibodies in H. pylori-related gastritis remains controversial. The purpose of our study was to determine the frequency of IgA-positive IgG-negative patients with symptoms of gastrointestinal (GI) disorders, thus assessing the clinical utility of IgA testing for H. pylori-related gastritis. It was found previously that the frequency of infected individuals in this category (IgA positive and IgG negative) is about 2%, but a large number of IgG-negative patients with GI disorders suggestive of H. pylori infection have not been investigated until now.

Antibodies, Bacterial↗
PubMed1996

Anti-glomerular basement membrane disease: role of enzyme-linked immunosorbent assays in diagnosis.

We compared two enzyme-linked immunosorbent assay (ELISA) tests with indirect immunofluorescence (IFA) for the measurement of anti-glomerular basement membrane (GBM) antibodies to study their sensitivity and specificity. The first ELISA test kit compared well to IFA (96.4% agreement, 93.3% sensitivity, 97.0% specificity). The second ELISA kit was much less sensitive (87.8% agreement, 63.3% sensitivity, 92.2% specificity). ELISA tests for the measurement of anti-GBM antibodies allow for quantitation and may have greater sensitivity than IFA. Sensitivity, however, may depend on the commercial test used.

Adolescent↗