Hereditary pancreatitis in the children of West Virginia.
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Abdominal Pain↗
Biomedical subjects
J A Hunt
Publications and source records attributed to J A Hunt.
Detection and characterization of transposable elements.
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Amino Acid Sequence↗
Image analysis in the evaluation of biomaterials.
An examination regime, based on a computer-aided image analysis system, has been developed for the quantitative evaluation of the local tissue response to biomaterials. This procedure involves the immunoenzymic staining of tissue sections using monoclonal antibodies specific for certain inflammatory cell types. An avidin-biotin-horseradish peroxidase staining method is used to identify antibody binding sites and the sections are assayed using a computer-aided image analysis system. This regime facilitates the rapid and accurate measurement of 30 cell related parameters in sections stained for macrophages, polymorphonuclear leucocytes, and other cells.
Animals↗
Quantitative in vivo assessment of the tissue response to dermal sheep collagen in abdominal wall defects.
We quantified the tissue response, tissue organization and patency of biodegradable patches for the repair of abdominal wall defects. We used dermal sheep collagen, cross-linked with hexamethylenediisocyanate in a model. The collagen patches were implanted either untreated or plasma polymerized with tetrafluoroethylene (TFE), to improve the properties of the patch for bowel adhesion and rate of degradation. The implants with surrounding tissue were retrieved after 3 d, 1, 2, 4, 6 and 8 wk, then sectioned and stained specifically for macrophages, neutrophils, T-lymphocytes and endothelium. Only macrophages and neutrophils were observed in the implant and surrounding tissue, with different antigen expression in the macrophages. This was found to be dependent on whether the macrophages were found within the implant or in the surrounding tissue. The neutrophils and macrophages were assessed using image analysis techniques to quantify the tissue responses to treated and untreated collagen, enabling comparison of the respective tissue responses. No significant differences were found between the two forms of this collagen. Infection played a key role in the severity of the tissue response around both types of implants, resulting in large variations in cell counts at each time period. Treating the collagen with TFE did not significantly improve its performance in this application.
Abdominal Muscles↗
Human neutrophil chemokinesis and polarization induced by hyaluronic acid derivatives.
Neutrophils and macrophages are known to undergo significant modifications in their morphology and basal metabolism in response to chemical factors, in particular changes in the shape, movement, phagocytic activity and degranulation. These phenomena often involve an increase in chemokinesis and cellular secretory activity, usually expressed in antimicrobial activity. Once activated, the cells can move quickly towards the source of the stimulus, where they produce and release great amounts of enzymes (e.g. proteases, hydrolases, lysozyme) and reactive oxygen metabolites (e.g. O2-., H2O2, OH.). This study has examined the ability of surfaces of selected biomaterials to influence neutrophil morphology and locomotion. The surface of two films derived from hyaluronic acid derivatives were compared with that of glass. The two hyaluronic acid derivatives, despite having a similar chemical structure, were shown to interact with human neutrophils in different ways. A hyaluronic acid ethyl ester stimulated the whole population of neutrophils to take up a non-spherical morphology (polarize) and to move with a velocity similar to that of N-formyl-methionine-leucine-phenylalanine-stimulated cells on a glass surface. In contrast, only 44% of the examined cells on the surface of hyaluronic acid benzyl ester were polarized and their mean speed was only slightly higher with respect to that found with non-stimulated cells on glass. Moreover, while on the benzyl ester and on glass a correlation between neutrophil circularity (i.e. the shape of the cell) and cell speed was found, the ethyl ester did not show any correlation.
Biocompatible Materials↗
Non-invasive magnetic resonance imaging of the soft tissue response to a biomaterial.
Magnetic resonance imaging (MRI) has been employed to visualize the tissue response to hydrogel implants in rats. High contrast MR images of the implant site were obtained. Distinct tissue variations in the MR images have been observed. These can be attributed to either the surgical procedure or the application of a tissue irritant to produce inflammation and have been verified histologically. This study demonstrates that MRI is potentially a useful tool for the non-invasive in-vivo evaluation of biomaterials.
Animals↗
Measurement of low calcium concentrations in cryosectioned cells by parallel-EELS mapping.
Electron energy loss spectroscopy (EELS) in the scanning transmission electron microscope provides a high sensitivity for microanalysis of certain important biological elements such as calcium whose physiological concentrations in cells are rather low. Application of parallel-EELS mapping to the analysis of freeze-dried cryosections of rapidly frozen tissue provides a means of detecting small amounts of calcium in structures with diameter approximately 50 nm. Detector pattern noise due to channel gain variations can be reduced by acquiring difference spectra at each pixel. By segmenting nitrogen maps that reflect the structure through the protein distribution it is possible to sum spectra from specific compartments. These are then processed by fitting reference spectra for the Ca L23-edge and the carbon background. It has been found that useful data can be collected at 100 keV beam energy from freeze-dried cryosections of cerebellar cortex cut to nominal thickness of 100 nm. The analysis results in a sensitivity of +/- 0.4 mmol Ca/kg dry weight with a total acquisition time of 400 s, a significant improvement over that achievable with energy-dispersive X-ray spectroscopy.
Animals↗
Phylogenetic relationships in Drosophila: a conflict between molecular and morphological data.
Grimaldi's recent cladistic classification of genera in the family Drosophilidae, based on adult morphological characters, is evaluated for those taxa for which alcohol dehydrogenase DNA sequences are also available. These data allow us to look at relationships of the Drosophila subgenera Sophophora and Drosophila with the Hawaiian Drosophila (Idiomyia) and with Scaptomyza, when Scaptodrosophila is used as an outgroup. The molecular data give strong support for the broad relationships hypothesized by Throckmorton, who contended that the subgenus Sophophora is a sister group to the remaining ingroup taxa. The Drosophila subgenus Engiscaptomyza, which Throckmorton regarded as intermediate between the Idiomyia (Hawaiian Drosophila) and Scaptomyza, is shown to be much more closely allied with Scaptomyza, in agreement with Grimaldi's results from adult morphology. The Hawaiian taxa, both Idiomyia and Scaptomyza, are firmly located as a sister group to the subgenus Drosophila, and these in turn all form a sister group to the subgenus Sophophora. Grimaldi's classification of these taxa is quite different and places the Hawaiian Drosophila (Idiomyia) as sister group to the remaining ingroup taxa (Scaptomyza and the subgenera Sophophora and Drosophila). Our results show that Grimaldi's new classification of these taxa results in paraphyletic groups, just as does the traditional classification under Throckmorton's interpretation of relationships. Additional data are required to produce a robust classification of this huge paraphyletic genus.
Alcohol Dehydrogenase↗
An example of an ecologic fallacy.
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Body Composition↗
Characterization of the thromboxane receptor mediating prostacyclin release from cultured endothelial cells.
The thromboxane A2 (TXA2) mimetic, 9,11-dideoxy-11,9-epoxymethano-prostaglandin F 2 alpha (U46619), mobilized calcium in the bovine aortic endothelial cell line AG4762 and stimulated release of prostacyclin from these cells. The U46619-stimulated release of prostacyclin could be inhibited by TXA2 antagonists with the order of potency [Is-[1 less than a, 2 less than b(5z), 3 less than b, 4 less than a]]-7-[3-[[2-[(phenylamino)carbonyl]hydrazino]methyl]-7-oxabicyclo- [2.2.1]hept-2-yl]-5- heptenoic acid (SQ29548) greater than 4-[2-(4-chlorobenzene-sulphonamido) ethyl]phenylacetic acid (BM13505) greater than 4-[2-(phenylsulphonamido)-ethyl]phenoxyacetic acid (BM13177), which was consistent with release being mediated by a TXA2 (TP) receptor. The TP receptor ligands, [3H]SQ29548 and 9,11-dimethylmethano-16(3-[125I]iodo-4-hydroxyphenyl)-13,14-dih ydr o-13-aza- 15-omega-o-tetranor-thromboxane ([125I]-PTA-OH), both appeared to bind to a homogenous population of sites in AG4762 cell membranes. The affinities of [3H]SQ29548 and [125I]PTA-OH were approximately 10 nM and approximately 0.3 nM, respectively, and the density of sites labelled by either ligand was approximately 25 fmol/mg protein. Under conditions where equilibrium was approached, the specific binding of [3H] SQ29548 or [125I]PTA-OH was displaced by SQ29548, BM13505 and BM13177 with the same order of potency and similar apparent affinities as in the functional assay, suggesting that these binding sites represent bona fide TP receptors.
Bradykinin↗
Recombinant basic fibroblast growth factor in red blood cell ghosts accelerates incisional wound healing.
The pharmacological manipulation of wound healing with locally applied growth factors is now a practical possibility. The effect of topical applications of recombinant basic fibroblast growth factor (bFGF) on the strength and cellularity of healing incisional rat skin wounds was investigated. Applications of bFGF in a simple vector (either a collagen suspension or saline) were not associated with any positive effects on wound breaking load at 7 days after injury in comparison with vector-treated control wounds; at the highest dose of 50 micrograms per wound, breaking loads were significantly decreased from a mean(s.e.m.) of 287(22) g/cm2 in controls to 201(23) g/cm2 (P < 0.005). Increasing doses of applied peptide were paralleled by increasing wound cellularity. Delay of bFGF release at the site of application was achieved by encapsulation into red blood cell ghosts. Wounds treated with bFGF in such ghosts were 50 per cent stronger than paired control wounds (388(27) versus 256(28) g/cm2, P < 0.002) 7 days after injury. Treated wounds were significantly more cellular at 4 days than paired control wounds. Topical applications of bFGF applied at the time of injury exert a positive effect on incisional wound strength only when a vector that delays release is used.
Administration, Topical↗
Stimulation of neutrophil movement by metal ions.
The interaction between corrosion products of metallic implants and the surrounding tissue is important in determining the biocompatibility of the implant, in particular the interaction of corrosion products with inflammatory cells such as neutrophils and macrophages. Such cells are capable of releasing enzymes and high-energy oxygen radicals which can damage the tissue. Clearly, any factors that influence cell movement to the implant site could influence the biocompatibility of the implant. The present study examined the influence that copper and nickel ions had on neutrophil locomotion. Both copper and nickel ions stimulated a proportion of the neutrophil population to take up a nonspherical morphology and to locomote. These metal ion stimulated cells have higher circularity values and move slower than neutrophils incubated with FMLP. For both FMLP and nickel ion stimulated cells, there is a correlation between the speed of neutrophil locomotion and neutrophil circularity; as the neutrophil circularity value decreases, the speed of locomotion increases.
Biocompatible Materials↗
A non-LTR retrotransposon from the Hawaiian Drosophila: the LOA element.
An interspersed sequence has been isolated from the genome of D. silvestris, a species endemic to the Hawaiian Islands. The LOA element is 7.7 kb long and its 3' end consists of (TAA)n tandem repeats. Five different LOA elements were isolated, of which three were truncated at their 5' ends. Large deletions within the elements were frequent. A consensus sequence of the LOA element has been constructed using the nucleotide sequence of three elements. Two overlapping open reading frames (ORF) are present in the LOA element. In ORF1 two 'cys' motifs characteristic for gag proteins are found. The protein translated from ORF2 has similarities with retroviral pol genes. A protein databank search revealed 22% to 25% identity with the reverse transcriptase domains of retrotransposons. This region also shows the pattern of invariant amino acid residues which are most conserved in retroviral reverse transcriptases. In ORF2 an integrase specific 'cys' motif and a conserved sequence of retroviral proteases were identified. Structural similarities with LINE-like elements suggest that the LOA element represents a new non-LTR retrotransposon.
Amino Acid Sequence↗
Evolution of the transposable element Uhu in five species of Hawaiian Drosophila.
The complete DNA sequence of three independent isolates of Uhu, a member of the Tc1-like class of transposable elements from D. heteroneura (Uhu-1, Uhu-3, and Uhu-4), has been determined. These isolates have between 95 and 96.4% nucleotide sequence identity indicating that Uhu is well conserved within this species. A comparison of the DNA sequences of Uhu and the D. melanogaster Hb1 transposable element shows that the nucleotide substitution rate for Uhu is comparable to the synonymous rate for the Adh gene in these species. Uhu has been identified in four other species of endemic Hawaiian Drosophila, D. silvestris, D. differens, D. planitibia and D. picticornis, and nine Uhu elements were isolated from genomic libraries of these four species. A 444 base pair region from within the coding region of the Uhu element, with well conserved ends, was amplified by the polymerase chain reaction and used for sequence comparison of elements from different species. The analysis of the sequence similarities between the elements within and between the species shows a grouping of the two pairs of most closely related species (D. heteroneura and D. silvestris, and D. differens and D. planitibia), but shows a much larger variation within the most recently diverged species (D. heteroneura and D. silvestris) than expected. There are extensive nucleotide substitutions and deletions in the Uhu elements from D. picticornis showing that they are degenerating and being lost in this species. These observations indicate that the Uhu element has been transmitted vertically and that transposition may have been activated at the time of formation of each species as it colonized the newly formed islands of the Hawaiian archipelago.
Amino Acid Sequence↗
Pathways of coagulation activation in situ in rheumatoid synovial tissue.
Immunohistochemical techniques were applied to rheumatoid synovium in order to detect components of coagulation and fibrinolysis pathways within these tissues. These techniques revealed an intact coagulation pathway and plasminogen activator inhibitor-2 associated with macrophage-like cells that were present throughout these tissues, especially in subsurface areas. Cell-associated thrombin generation appeared to account for conversion of abundant fibrinogen to fibrin. Occasional macrophage-like cells also stained for urokinase but tissue-type plasminogen activator and plasminogen activator inhibitor-1 were restricted to vascular endothelium. Intense synovial fibrin deposition (with the limited evidence for associated fibrinolysis) may contribute to local inflammation and explain certain clinical features of rheumatoid arthritis. These findings suggest novel treatment hypotheses for this disease.
Arthritis, Rheumatoid↗
Evaluation of soft tissue response to a poly(urethane urea).
Variations in the performance of vascular prostheses constructed of polyurethanes, and some evidence which suggested that these variations could be due not to the properties of the polymer itself, but to differences in the cellular response to the various microstructures of porous polyurethanes require investigation. Experiments were performed to evaluate quantitatively the extent of the cell behaviour adjacent to a series of polyurethane samples. It was shown that, with Biomer, a polyurethane urea, the profile of cell behaviour as a function of distance from the implant surface and of time following implantation, the response of cells in general and macrophages in particular, varied considerably with different internal microstructure. This supports the suggestion that the cellular response to different structures and susceptibility to degradation are related.
Animals↗
Foot infections in diabetes are rarely due to a single microorganism.
The purpose of this study was to investigate the frequency with which multiple organisms can be isolated from severe foot infections in diabetic patients with carefully planned techniques of collection and processing of specimens. One hundred and seventy-seven organisms were isolated from 52 patient admissions (mean 3.4 per infection) at a district hospital. This was compared to a mean of 2.1 organisms per lesion at a local university hospital and 2.3 at a smaller community hospital. Staphylococcus aureus was isolated in about half of all lesions at the three hospitals, while anaerobic organisms were isolated from 30 at the district hospital, 10 at the university hospital, and 4 at the community hospital. This study concludes that, firstly, proper techniques for collection, transportation and examination of culture specimens are important in the isolation of multiple organisms from foot infections in diabetes, and secondly, Staphylococcus aureus is often absent while anaerobic organisms are common.
Aged↗
Heterotopic bone formation in abdominal incisions.
Heterotopic bone formation in vertical abdominal wounds is a not infrequent and sometimes disabling complication of abdominal surgery, occurring predominantly in males. Excision of the bone is indicated only for marked discomfort or pain, usually produced by an active lifestyle. Under these circumstances, recurrence of bone following excision, would be highly undesirable and the prophylactic use of etidronate disodium may well be indicated to prevent new bone formation, as demonstrated by one of our cases (Case 8).
Abdomen↗