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Biomedical subjects

L Hyde

Publications and source records attributed to L Hyde.

At least 19 recordsLinked to original sources
PubMed2003

Extracellular MUC3 mucin secretion follows adherence of Lactobacillus strains to intestinal epithelial cells in vitro.

BACKGROUND: Mucins are large complex glycoproteins that protect intestinal mucosal surfaces by limiting access of environmental matter to their epithelial cells. Several mucin genes have been described, including MUC3 that is a membrane associated mucin of the small intestine. Increased MUC3 mRNA transcription is induced by incubation of intestinal epithelial cells with a Lactobacillus strain known to be adherent to them. AIMS: To determine whether increased epithelial cell MUC3 mucin expression in response to Lactobacillus strains results in increased extracellular secretion of MUC3 mucins and the importance of epithelial cell adherence in modulation of MUC3 mucin expression. METHODS: HT29 cells grown to enhance expression of MUC3 mucins were incubated with selected Lactobacillus strains. Spent cell culture medium was collected for detection of secreted MUC3 mucins using dot blot immunoassay with a generated MUC3 antibody. Post-incubation HT29 cell RNA was collected for analysis of MUC3 expression by northern blot analysis using a MUC3 cDNA probe. In vitro binding studies using Lactobacillus strains incubated alone or coincubated with enteropathogenic Escherichia coli strain E2348/69 were used for adherence and inhibition of adherence studies, respectively. RESULTS: Lactobacillus strains with minimal ability to adhere to HT29 cells failed to induce upregulation of mucin gene expression. There was a direct correlation between upregulation of MUC3 mucin mRNA expression and extracellular secretion of MUC3 mucin. The same Lactobacillus strains that increased extracellular secretion of MUC3 mucin led to reduced adherence of enteropathogen E coli E2348/69 during coincubation experiments. CONCLUSION: Probiotic microbes induce MUC3 mucin transcription and translation with extracellular secretion of the MUC3 mucins. Epithelial cell adherence enhances the effects of probiotics on eukaryotic mucin expression.

Bacterial Adhesion↗
PubMed2000

Performance of the ImmunoCard STAT! E. coli O157:H7 test for detection of Escherichia coli O157:H7 in stools.

ImmunoCard STAT! E. coli O157:H7 (Meridian Diagnostics, Inc., Cincinnati, Ohio) is a novel rapid (10-min) test for the presence of Escherichia coli O157:H7 in stools. The test may be performed either directly on stool specimens or on an overnight broth culture of stool. In a multicenter prospective study, 14 of 14 specimens positive by culture for E. coli O157:H7 were positive by the ImmunoCard STAT! O157:H7 test, and there were no false positives from 263 culture-negative specimens. In a retrospective study, the test was positive in 339 (81%) of 417 stored culture-positive specimens and the specificity was 95% (98 of 103 specimens). No false positives were associated with alternate stool pathogens. The ImmunoCard STAT! O157:H7 test has high sensitivity and specificity.

Enzyme-Linked Immunosorbent Assay↗
PubMed2000

Altered activity, social behavior, and spatial memory in mice lacking the NTAN1p amidase and the asparagine branch of the N-end rule pathway.

The N-end rule relates the in vivo half-life of a protein to the identity of its N-terminal residue. N-terminal asparagine and glutamine are tertiary destabilizing residues, in that they are enzymatically deamidated to yield secondary destabilizing residues aspartate and glutamate, which are conjugated to arginine, a primary destabilizing residue. N-terminal arginine of a substrate protein is bound by the Ubr1-encoded E3alpha, the E3 component of the ubiquitin-proteasome-dependent N-end rule pathway. We describe the construction and analysis of mouse strains lacking the asparagine-specific N-terminal amidase (Nt(N)-amidase), encoded by the Ntan1 gene. In wild-type embryos, Ntan1 was strongly expressed in the branchial arches and in the tail and limb buds. The Ntan1(-/-) mouse strains lacked the Nt(N)-amidase activity but retained glutamine-specific Nt(Q)-amidase, indicating that the two enzymes are encoded by different genes. Among the normally short-lived N-end rule substrates, only those bearing N-terminal asparagine became long-lived in Ntan1(-/-) fibroblasts. The Ntan1(-/-) mice were fertile and outwardly normal but differed from their congenic wild-type counterparts in spontaneous activity, spatial memory, and a socially conditioned exploratory phenotype that has not been previously described with other mouse strains.

Amidohydrolases↗
PubMed1998

Sensitivities and specificities of premier E. coli O157 and premier EHEC enzyme immunoassays for diagnosis of infection with verotxin (Shiga-like toxin)-producing Escherichia coli. The SYNSORB Pk Study investigators.

This study describes the performance of two rapid enzyme immunoassays, Premier E. coli O157 and Premier EHEC (Meridian Diagnostics Inc., Cincinnati, Ohio) for the detection in stools of Escherichia coli O157 and verotoxins (Shiga-like toxins), respectively. Both tests were performed on stools from 876 children presenting to eight emergency departments with diarrhea. Standard culture, including E. coli O157:H7 isolation, was performed, and paired sera were taken for anti-O157-lipopolysaccharide antibody determination. Stools from patients enrolled in the study, and those yielding discordant results, were sent to a reference laboratory for repeat testing and further investigation, including cytotoxicity and non-O157 verotoxin-producing E. coli culture. Results were classified as field results (obtained in the eight site laboratories) and resolved results (obtained after repeat testing in the central laboratory). The "gold standard" for sensitivity of both tests and for specificity of Premier E. coli O157 was isolation of E. coli O157:H7 or a fourfold anti-O157 antibody rise. Specimens positive by the Premier EHEC test and negative for E. coli O157 culture were examined for non-O157 verotoxin-producing E. coli. The field sensitivity of Premier E. coli O157 was 86%, that of Premier EHEC was 89%, and the specificity of Premier E. coli O157 was 98%. Ten of 13 discordant Premier E. coli O157 results were reassigned as true results after repeat testing. Ten non-O157 verotoxin-producing E. coli isolates were recovered from Premier EHEC-positive, E. coli O157 culture-negative stools. Only one specimen gave an unequivocally false-positive Premier EHEC result. Both tests are highly sensitive and are specific if correctly performed. The Premier EHEC test will be particularly valuable as a practical routine test for the detection of non-O157 verotoxin-producing E. coli.

Antibodies, Bacterial↗
PubMed1996

Sending a copy of the letter to the general practitioner also to the parents in a child development centre: does it work?

Following concerns that a considerable extra workload would be involved in sending a copy of the GP outpatient letter to parents following a medical consultation, 100 consecutive letters from the CDC were analysed to see if they could be sent to parents. Changes would have been necessary in 11, of which 6 would need an extra letter to the GP conveying additional specific information. Letters were generally intelligible, but it was recommended that they could be written in a more simple way for parents. Following these recommendations, copies of letters to the GP were sent to parents and the practice reviewed 2 years later. GP letters from 100 consecutive patients who had just visited the Centre were analysed and found to have been sent in 94. Of the remaining six, five were not sent because they contained information specific to the GP. It was felt that this could be rectified fairly easily. An anonymous questionnaire, sent to those receiving a copy of the letter, indicated that it had been very well received. It was felt that this policy was most helpful to the parents and justified a small additional workload.

Child↗
PubMed1993

Reconstitution of a purified mu-opioid binding protein in liposomes: selective, high affinity, GTP gamma S-sensitive mu-opioid agonist binding is restored.

An opioid binding protein (OBP) purified to homogeneity from bovine striatal membranes has been reconstituted in liposomes. The liposomes were produced by PEG-precipitation of OBP in the presence of a CHAPS extract of bovine striatum, devoid of opioid binding. High affinity mu-agonist binding was restored. The binding was selective for mu-agonists, stereospecific and inhibited by GTP gamma S. These results demonstrate that there is recoupling of OBP with G-protein and confirm our earlier evidence that the purified OBP is a mu-opioid binding site.

Animals↗
PubMed1991

Stilbene disulfonic acids. CD4 antagonists that block human immunodeficiency virus type-1 growth at multiple stages of the virus life cycle.

The stilbene disulfonic acids 4,4'-diisothiocyanatostilbene-2,2'-disulfonic acid (DIDS), 4,4'-diisothiocyanatodihydrostilbene-2,2'-disulfonic acid and, 4-acetamido-4'-isothiocyanatostilbene-2,2'-disulfonic acid bound the variable-1 immunoglobulin-like domain of CD4 on JM cells. The interaction blocked the binding of the anti-CD4 monoclonal antibody OKT4A and the envelope glycoprotein gp120 of the human immunodeficiency virus type-1 (HIV-1). DIDS inhibited the acute infection of CD4+ cells by HIV-1 with a potency (IC50 approximately 30 microM) similar to that which blocked gp120 binding (IC50 approximately 20 microM) to the cellular antigen. Pretreating uninfected CD4+ C8166 cells with DIDS blocked their fusion with chronically infected gp120+ cells. DIDS covalently and selectively modified lysine 90 of soluble CD4 and abolished the gp120-binding and antiviral properties of the recombinant protein. When added to cells productively infected with HIV-1, DIDS blocked virus growth and cleared cultures of syncytia without inhibiting cellular proliferation. The stilbene disulfonic acids are a novel class of site-specific CD4 antagonists that block multiple CD4-dependent events associated with acute and established HIV-1 infections.

4,4'-Diisothiocyanostilbene-2,2'-Disulfonic Acid↗
PubMed1985

The neonatal development of benzodiazepine receptor subtypes in the rat cerebral cortex and cerebellum.

The development of benzodiazepine receptor subtypes in the rat cerebral cortex and cerebellum was studied. The proportions of Type I (CL218872 sensitive binding sites) and Type II (CL218872 insensitive binding sites) in both regions of the neonatal brain were quite different from those of adult. In one day old rat cortex and cerebellum, about 95% of the benzodiazepine receptor were Type II receptor, while these receptors comprised about 50% and 15% of the total in the adult cortex and cerebellum, respectively. From 21 days onward, these ratios in both brain regions did not significantly change through adult age (over 55 days old). The proportion of receptor subtypes in the 21 day cortex (50% type I, 50% type II) was approximately equivalent to that seen in the cerebellum at the 9th day of age. The 3H-flunitrazepam specific binding sites in both brain regions increased markedly after birth, although Type II receptor binding sites did not show any notable gain. Type II receptor specific binding sites in the cortex were not significantly different between neonatal and adult, while these sites in the cerebellum to decrease after birth. These results suggest that Type I and Type II receptors seemed to develop independently during their embryogenesis.

Age Factors↗
PubMed1978

Combined chemotherapy for squamous cell carcinoma of the lung.

One hundred sixty-seven patients with extensive well-differentiated and 120 patients with extensive poorly differentiated squamous cell carcinoma of the lung received chemotherapy as part of a randomized study by the Veterans Administration Lung Group. Chemotherapy was administration at random using one of the following four regimens: (1) cyclophosphamide alone; (2) cyclophosphamide plus 1-(2-chloroethyl)-3-cyclohexyl-1-nitrosourea (CCNU); (3) doxorubicin (adriamycin) plus cyclophosphamide; and (4) doxorubicin plus CCNU. With data on survival as the criteria for evaluation, it has been shown that combined chemotherapy using doxorubicin plus cyclophosphamide achieves greater median survival for patients with squamous cell cancer of the lung than single-drug chemotherapy using cyclophosphamide, under the conditions of this study; however, prolongation of life is still minimal, and better treatment is required. About 20 percent of the patients receiving any of the four regimens developed serious toxic effects from therapy with the drugs.

Carcinoma, Squamous Cell↗