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Biomedical subjects

E Elliott

Publications and source records attributed to E Elliott.

At least 19 recordsLinked to original sources
PubMed1995

Paraformaldehyde fixation of neutrophils for immunolabeling of granule antigens in cryoultrasections.

Paraformaldehyde (PFA) fixation was optimized to facilitate the immobilization and labeling of multiple granule antigens, using short fixation regimens and cryoultramicrotomy of unembedded neutrophils (PMNs). In the optimal protocol, extraction of azurophil granule antigens (especially of the abundant elastase) was obviated by manipulating the polymeric state of PFA, and hence its rate of cross-linking, by altering its concentration and pH in a multistep process. Primary fixation conditions used (4% PFA, pH 8.0, 5 min) favor fixative penetration and rapid cross-linking. Stable cross-linking of the antigen was achieved in a secondary fixation step using conditions that favor larger, more cross-linking polymeric forms of PFA (8% PFA, pH 7.2, 15 min). Immobilization of granule antigens was enhanced by flotation of cut sections on fixative (8% PFA, pH 8.0) before labeling and by using post-labeling fixation with 1% glutaraldehyde. The optimized protocol facilitated immobilization and immunolabeling of elastase, myeloperoxidase, lactoferrin, and cathepsin D in highly hydrated, unembedded PMNs.

Antibodies↗
PubMed1994

Modulation of host response to Escherichia coli o157:H7 infection by anti-CD18 antibody in rabbits.

BACKGROUND/AIMS: Escherichia coli O157:H7 infection induces diarrhea, severe colitis, and colonic electrolyte transport abnormalities characterized by decreased Na absorption and Cl secretion. The aim of this study was to examine the role of the host inflammatory response in inducing distal colonic transport changes during infection with E. coli O157:H7. METHODS: New Zealand white rabbits aged 10 days were infected with E. coli O157:H7 strain EDL933 (plasmid+, verotoxin 1+, verotoxin 2+). Studies were performed daily from day 1 to day 5 postinfection and compared with uninfected controls (10 days old). Distal colonic ion transport was studied in vitro under short-circuited conditions in Ussing chambers, and tissue inflammation was assessed by mucosal myeloperoxidase activities and mucosal neutrophil (polymorphonuclear neutrophil [PMN]) counts. In a second study, PMN infiltration was inhibited by an anti-CD18 (leukocyte adhesion molecule) monoclonal antibody, IB4, and histology and transport were studied on day 5 postinfection. RESULTS: Infection with O157:H7 induced diarrhea and inhibition of Na absorption by day 3. CI secretion occurred on day 5, coincident with tissue infiltration with PMN. Pretreatment with IB4 prevented histological damage and tissue infiltration with PMN, and it inhibited the transport abnormalities induced by infection alone. CONCLUSIONS: Infection with O157:H7 reduces Na absorption and stimulates Cl secretion in the distal colon. Disruption of the epithelium and changes in colonic electrolyte transport during enterohemorrhagic E. coli are mediated by the host inflammatory response.

Animals↗
PubMed1994

Regulation of glucose transport and expression of GLUT3 transporters in human circulating mononuclear cells: studies in cells from insulin-dependent diabetic and nondiabetic individuals.

We have previously shown that human circulating mononuclear cells (CMCs) respond to physiological concentrations of insulin with a rapid increase in glucose transport rate. The responding cells were found to be the monocytes, and cells derived from individuals with insulin-dependent diabetes mellitus (IDDM) had lower basal and insulin-stimulated glucose transport rates. Of interest, both cell types were found to express the GLUT1 but not the typical insulin-responsive GLUT4 transporter isoform. To further study the mechanisms responsible for stimulation of transport in these cells, we investigated (1) the response to insulin-like growth factor-I (IGF-I) and insulin-mimetic agents, and (2) the expression of other glucose transporter isoforms in CMCs of nondiabetic and IDDM individuals. The time course of insulin-stimulated glucose uptake in CMCs was rapid, reaching a plateau within 30 minutes. CMCs showed a dose-dependent and highly sensitive increase in glucose uptake to IGF-I (maximal response reached at 0.1 to 0.5 nmol/L IGF-I). The IGF-I dose-response curve was similar for CMCs of control and IDDM individuals, but both the basal and maximal response to IGF-I were lower in the diabetic group (P < .01). CMCs did not respond to vanadate, lithium, hydrogen peroxide, or short incubation (1 hour) with metformin, but glucose uptake increased in response to peroxides of vanadate and longer-duration (14 hours) metformin incubations. The glucose transporter isoforms of separated monocytes and lymphocytes were further investigated by Northern blotting of total RNA with a GLUT3-specific cDNA probe and by Western blotting of total membranes using GLUT3-specific antiserum.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1994

Novel features of tumors that secrete both growth hormone and prolactin in acromegaly.

The most prominent previously reported clinical features of growth hormone (GH) and prolactin (PRL)-secreting pituitary adenomas associated with acromegaly have included the high incidence of galactorrhea in women and a generally more favorable response to dopamine agonist therapy. The authors analyzed a consecutive series of 62 acromegalic patients treated with transsphenoidal microsurgery. GH-PRL tumors were found in 30% of the patients. There was a significant difference in sex distribution between acromegalics with the GH-PRL tumor subtype and all other acromegalics. Women represented 73% of the GH-PRL immunostain subtype, as compared with the overall sex distribution of 33 women (53%) and 29 men (47%) for the entire series of acromegalic patients. Individuals with the GH-PRL subtype had significantly higher postoperative GH levels than those with the GH subtype, and significantly higher postoperative GH levels when compared with all other acromegalics with a variety of immunostain subtypes. Linear regression analysis of the pre- and postoperative GH data revealed that the increased postoperative GH levels in the GH-PRL immunostain subtype were independent of the invasiveness of the tumor and of sex of the subject. When the same linear regression technique was used, lower preoperative levels of thyroxine and thyroid-stimulating hormone were observed in the GH-PRL subtype. These data suggest inherent differences characteristic of tumors that secrete both growth hormone and prolactin.

Acromegaly↗
PubMed1993

Cancer epidemiology among styrene-butadiene rubber workers.

The standardized mortality ratios for some cancers of the lymphohaematopoietic system were high in an early cohort analysis. Since the presence of large numbers of unexposed workers could conceal risks within a cohort, a case-control study was designed to examine the relationship between estimated exposures and the occurrence of these cancers. The results suggested that the risk for leukaemia was associated with exposure to butadiene and with work in specific areas. Modelling, using rank scores, indicated an increase in the risk for leukaemia with increasing exposure score. Use of cases validated by review of hospital records and selection of a new set of controls did not change the findings. The data indicated that comparison of scores within the same time frame improved the model and increased the estimated odds ratio, suggesting that exposure time or dose rate may prove to be the important variable for risk. Exact measurements from the companies involved showed significant correlations between assigned ranks and level of exposure derived from personal monitoring for butadiene but not for styrene. Thus, use of the measured values might be expected to show an association between leukaemia and exposure to butadiene. The standardized mortality ratio for leukaemia among long-term workers hired before 1960 who had worked in the three plants where the geometric mean butadiene level was three to five times higher than those in the other plants is 1.8 times higher than that of the US population. An appropriate algorithm for comparing cases and controls on the bases of the measured samples is being developed.

Butadienes↗
PubMed1992

Improving memory and control beliefs through cognitive restructuring and self-generated strategies.

Memory problems are a major source of concern among older adults. The goal of this research was to evaluate methods for improving memory performance and beliefs about memory ability and control. Men and women between the ages of 60 and 85 were randomly assigned to one of five treatment groups: (1) cognitive restructuring to promote adaptive beliefs about memory, (2) memory skills training, (3) combined cognitive restructuring and memory skills training, (4) practice on memory tasks, and (5) a no-contact control group. Beliefs about memory (ability and control) and memory performance (working memory, recall of text materials, categorizable word list, and names and faces) were assessed at a pretest and two posttests. As predicted, those receiving the combined treatment showed the greatest increases in their sense of control and perceived ability to improve memory. Results indicated that all groups improved equally on the memory tasks, although those who had received memory training were more likely to report at the second posttest that they had begun using new strategies for remembering things.

Adaptation, Psychological↗
PubMed1992

Age-specific sero-prevalence of amoebiasis and giardiasis in southern Indian infants and children.

The age-specific sero-prevalence of amoebiasis and giardiasis was estimated in 91 pediatric diarrhoea and in 70 non-diarrhoeal cases from Southern India. Anti-amoeba/giardia IgG assays on 20 children with inflammatory bowel disease from the UK yielded base-line levels in a non-endemic symptomatic population. IgG, IgM, and IgA levels were estimated to E. histolytica and G. lamblia using an ELISA. Concomittant faecal examinations were done for the Indian children. There was a significant correlation between acquisition of sero-positivity and age. A rise in the IgG response to both organisms was evident between 38 and 47 and 13-24 months, respectively, in diarrhoeal and non-diarrhoeal cases. An appreciable IgM response occurred predominantly in diarrhoea cases and at a younger age (less than 24 months). IgA responses were low. Anti-protozoal IgG levels in the UK children were negligible. There was no relationship between faecal excretion and sero-positivity. The study shows an age-related antibody response to E. histolytica and G. lamblia.

Age Factors↗
PubMed1991

Anti-peptide antibodies to cathepsins B, L and D and type IV collagenase. Specific recognition and inhibition of the enzymes.

Anti-peptide antibodies were raised against synthetic peptides selected from the sequences of human cathepsins B and L, porcine cathepsin D and human type IV collagenase. Sequences were selected from the active site clefts of the cathepsins in the expectation that these would elicit immunoinhibitory antibodies. In the case of type IV collagenase a sequence unique to this metalloproteinase subclass and suitable for immunoaffinity purification, was chosen. Antibodies against the chosen cathepsin B sequence were able to recognize the peptide but were apparently unable to recognise the whole enzyme. Antibodies against the chosen cathepsin L sequence were found to recognise and inhibit the native enzyme and were also able to discriminate between denatured cathepsins L and B on Western blots. Antibodies against the chosen cathepsin D sequence recognised native cathepsin D in a competition ELISA, but did not inhibit the enzyme. Native type IV collagenase was purified from human leukocytes by immuno-affinity purification with the corresponding anti-peptide antibodies.

Amino Acid Sequence↗
PubMed1991

Serum antibody response in children with Giardia lamblia infection and identification of an immunodominant 57-kilodalton antigen.

Giardia lamblia antigens which react with sera from children with G. lamblia infection were investigated by sodium-dodecyl polyacrylamide gel electrophoresis and immunoblotting. Serum IgG, IgM and IgA response to the antigens were immunochemically characterized. Serum antibodies from all giardiasis patients, but none of the controls, was found to react with a 57-kilodalton antigen. The 57 kDa antigen elicited IgG and IgA but not IgM antibodies. The protein nature of the 57 kDa antigen was demonstrated by loss of antibody recognition after trypsin treatment of G. lamblia trophozoites. Subcellular fractionation of G. lamblia trophozoites followed by SDS-PAGE and immunoblotting showed that the 57 kDa antigen was probably not a component of the cytoskeleton.

Animals↗
PubMed1990

Analysis of colloidal gold probes by isoelectric focusing in agarose gels.

Colloidal gold particles of different size (3-20 nm in diameter) were prepared by tannic acid-citrate and citrate reduction methods. From these colloids, different probes were prepared using sheep anti-rabbit antiserum, sheep anti-rabbit IgG, bovine serum albumin, polyethylene glycol, and protein A as the primary stabilizers and polyethylene glycol and/or bovine serum albumin as secondary and tertiary stabilizers, in different combinations. The probes were analyzed by isoelectric focusing in agarose gels, which allow the migration of particles in the size range 3-20 nm. (P. Sewer and S. J. Hayes, 1986, Anal. Biochem. 158, 72-78). Isoelectric focusing revealed that the surface charge of colloidal gold probes is dependent upon the size of the gold particle, the reduction method used, the primary ligand, and the pH at which this is adsorbed, as well as upon the secondary and tertiary stabilizers used. It is proposed that such differences in surface charge may underlie the different results which may sometimes be observed in colloidal gold labeling, especially when novel ligands are used.

Colloids↗
PubMed1989

Genetics and expression of the Q6 and Q8 genes. An LTR-like sequence in the 3' untranslated region.

A unique 2.2-kb mRNA is transcribed from the Q6 and Q8 genes of the mouse major histocompatibility complex. RNase protection experiments and DNA sequence analysis have mapped the 3' terminus to a site located 1110 bp downstream from exon 8. Comparison of the 3' sequence of Q8 to that of Q7 revealed that the two genes diverge from one another at a point located 200 bp into the untranslated domain. This finding explains the increased size of the transcript. RNase protection experiments involving twelve different strains of mice have revealed few sequence polymorphisms. A tissue distribution of the 2.2-kb transcript in B6 mice revealed that the highest quantities of message were present in the spleen with decreasingly lower amounts in the thymus, liver, kidney, testis, and brain. The H-2r haplotype appeared novel; it is phenotypically Qa-2-, yet expressed a 2.2-kb transcript which hybridizes to a Q8 probe. A comparison of a Qa-2hi expressor, B6, and a Qa-2low expressor, BALB/cFla, has established that these quantitative cell surface differences are reflected in mRNA differences. A homology search of the Genbank database has revealed that the 3' portion of Q8 contains extensive homology to a retrovirus-like long terminal repeat sequence that is characteristic of an embryonic-specific transposon (ETn).

Alleles↗
PubMed1988

Water, electrolyte, glucose, and glycine absorption in rat small intestinal transplants.

Water, electrolyte, glucose, and glycine absorption were studied in vivo in successful rat small intestinal transplants. Isolated bowel loops were transplanted from F1 hybrids into parental strain Lewis rats. A 7-day course of cyclosporin A was given for immunosuppression. Absorption was studied using a steady-state perfusion technique at either 9 or 21 days after transplantation. Histologic examination showed there was villus shortening with time but no evidence of rejection. When perfused with isotonic saline, both allografts and controls secreted water. However, allografts and denervated controls secreted chloride, whereas innervated controls absorbed chloride (p less than 0.05). There was a marked reduction in water and sodium absorption from 30 mM glucose-saline in transplanted loops and denervated controls, whereas glucose absorption was relatively preserved in these groups at 9 days (p less than 0.01). These changes could not be accounted for by rejection or ischemia. These studies demonstrate that denervation may be a major limiting factor in intestinal transplantation.

Animals↗
PubMed1987

Novel mRNA species from a Q-subregion class-I gene of the murine major histocompatibility complex.

A novel mRNA species is specified by the Q6/Q8 gene, a member of the Qa-2-determining family of class-I genes of the murine major histocompatibility complex. It is longer than all previously described class-I transcripts due to an extension at the 3' end of the mRNA past the predicted polyadenylation site. This mRNA was detected by Northern-blot analyses with single or low-copy-number probes to the 3' end of the Q6/Q8 gene. RNase protection experiments have confirmed this finding. The appearance of this mRNA in different strains of mice correlates with the synthesis of the Qa-2 molecule.

Animals↗
PubMed1985

Immediate free vascularized joint transfer from second toe to index finger proximal interphalangeal joint: a case report.

The results of treatment of severe injuries to the proximal interphalangeal joint are unsatisfactory. The methods of joint reconstruction are discussed, including fusion, implant arthroplasty, perichondrial grafting and vascularized joint transfer. A patient is presented with a severe crush injury to the dorsum of the index finger with loss of skin and extensor tendon and proximal interphalangeal joint disruption. Immediate reconstruction of the finger is described using a composite free flap of skin, extensor tendon and proximal interphalangeal joint from the second toe. Follow-up at two years is described, demonstrating proximal interphalangeal motion and finger function.

Adult↗