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Biomedical subjects

A Jones

Publications and source records attributed to A Jones.

At least 541 records · Page 30Linked to original sources
PubMed1988

Oral toxicity of a bloom of the Cyanobacterium microcystis Aeruginosa administered to mice over periods up to 1 year.

Cyanobacterial blooms in lakes have been reported causing livestock deaths and liver injury to human populations. In this study bloom material consisting of Microcystis aeruginosa was collected from a farm water storage after the death of sheep drinking from it. The cyanobacterial cells were lysed and a cell-free extract was provided to mice at a series of dilutions as their only source of drinking water. Mice of both sexes, with controls, were killed at intervals up to 1 yr of administration. Autopsies, histopathological examination, and analyses of plasma lactate dehydrogenase and alanine aminotransferase were carried out. Increased mortality was observed, particularly among males, together with chronic active liver injury and elevated alanine aminotransferase in blood. In control mice and those receiving lower concentrations of extract, hepatic amyloidosis with neutrophil infiltration, and bronchopneumonia, were seen with increasing age. The bronchopneumonia appeared earlier among mice receiving cyanobacterial extract. Four tumors were seen in 71 mice receiving a high concentration of extract for up to 1 yr, none in 150 mice receiving lower concentrations, and 2 in 73 control mice. No effects on male or female fertility, embryonic mortality, neonatal viability, or skeletal development were observed, but 7 out of 73 neonatal mice born to parents given cyanobacterial extract showed reduced brain size. No cases were seen in controls. We conclude that the major toxicity exhibited is liver injury. Further attention is needed for evaluation of carcinogenicity and embryonic damage.

Administration, Oral↗
PubMed1988

Procoagulant induction by human lymphokine and interferon gamma/PMA on a myelomonocytic cell line, RC2a.

The human myelomonocytic cell line RC2a expressed procoagulant activity following stimulation with human lymphokine (LK) prepared by stimulating peripheral blood mononuclear cells with either mitogens (Concanavalin A, phytohaemagglutinin or antigen (tuberculin). Induction was rapid, with optimal activity observed between 6 and 8 h, was decreased in cultures containing serum and was not inhibited by actinomycin D or cycloheximide. The LK activity was not inhibited by an anti-interferon gamma (IFN gamma) antibody. IFN gamma and phorbol myristate acetate (PMA) had no activity but acted in synergy to induce procoagulant expression; interferon alpha plus PMA were without effect. In contrast to the LK-induced response, procoagulant induced by IFN gamma/PMA was not detected for up to 8 h and steadily rose over 24-48 h culture and was dependent on new protein and RNA synthesis. Bacterial lipopolysaccharide, a potent inducer of thromboplastin on normal human monocytes, failed, either alone or in combination with LK, IFN gamma, PMA or IFN gamma plus PMA, to activate procoagulant expression on RC2a cells. Both LK and IFN gamma/PMA-induced procoagulant had properties of thromboplastin expressed both intracellularly and on intact, viable cells. This study shows that RC2a cells are responsive to factors produced as the result of an activated cell-mediated immune response which may therefore contribute to the coagulopathies common to this form of malignancy.

Blood Coagulation Factors↗
PubMed1988

Kinetics of the bronchoalveolar leucocyte response in rats during exposure to equal airborne mass concentrations of quartz, chrysotile asbestos, or titanium dioxide.

The kinetics of the bronchoalveolar response was assessed in rats exposed, at equal airborne mass concentration (10 mg/m3), to titanium dioxide--a non-pathogenic dust--and the two pathogenic mineral dusts quartz and chrysotile asbestos. Rats were killed at intervals over a 75 day exposure period and groups of rats exposed for 32 and 75 days after recovery for two months. Bronchoalveolar lavage was carried out and the lavage fluid characterised for cellular content, macrophage activation, and concentrations of free total protein, lactate dehydrogenase, and N-acetyl-beta-D-glucosaminidase. Inhalation exposure to the two pathogenic dusts resulted in an increased number of leucocytes, macrophage activation, and increased levels of free enzymes and total protein. The pattern and magnitude of the responses to quartz and chrysotile differed. Chrysotile caused less inflammation than quartz, and the main cellular response peaked around the middle of the period of dust exposure whereas the highest levels of enzymes occurred towards the end. The difference in timing suggests that macrophages were not available for lavage towards the end of the exposure, owing to their playing a part possibly in deposition of granulation tissue. Quartz caused a greater cellular and enzyme response than chrysotile, particularly towards the end of the dust exposure phase. There was a noticeable progression of inflammation in the quartz exposed groups left to recover for two months, but not in the chrysotile recovery groups.

Animals↗
PubMed1988

Acute abdominal pain in children.

This preliminary communication describes the initial results of a further special study investigating the disease spectrum and clinical presentation in a total of 1080 children admitted to hospital with acute abdominal pain (677 from the Children's Hospital, Sheffield, England, and the remaining 403 from hospitals in Paris, Oslo, Copenhagen, and Deventer). The disease spectrum in children differs radically from that in adults, well over 90% of cases being due to either acute appendicitis or non-specific abdominal pain (NSAP). The clinical presentation of both appendicitis and NSAP was found to differ from that in older age groups. These findings imply clearly that the use of the existing OMGE database for computer-aided diagnosis--using data drawn from cases of all ages--may not be optimal in children. A fresh database (using only children's data) was therefore created and tested. Its sensitivity for appendicitis was equivalent to that of inexperienced clinicians (79.6% versus 77.3%). The computer's specificity (over 70%) was higher than that of clinicians (52.7%). The findings also re-emphasise the value of disciplined data collection, and the implications for teaching are discussed.

Abdomen, Acute↗
PubMed1987

Unfolding of iron and copper complexes of human lactoferrin and transferrin.

1. Human lactoferrin and transferrin are capable of binding two iron or copper ions into specific binding sites in the presence of bicarbonate. 2. Urea and several alkyl ureas have been effective in unfolding these metal-protein complexes. 3. Biphasic transitions are observed for the unfolding of each of the metal complexes of these proteins as determined by direct visible spectroscopy suggesting the release of iron(III) and Cu(II) ions from both of these metal-binding proteins during the unfolding process. 4. Greater stabilization and increased resistance to protein unfolding is observed for all iron(III) complexes compared to Cu(II) complexes of lactoferrin and transferrin as determined by isothermal unfolding and thermal denaturation. 5. Relative stabilization of the different metal-protein complexes investigated within this study were determined to be as follows: Lf-Fe(III) greater than Lf-Cu(II); Tf-Fe(III) greater than Tf-Cu(II), and Lf-Fe(III) greater than Tf-Fe(III); Lf-Cu(II) greater than Tf-Cu(II).

Circular Dichroism↗
PubMed1987

Interspecific characterization of several taeniid cestodes by isoenzyme analysis using isoelectric focusing in agarose.

Taenia cestodes were obtained from 5 different definitive host species in Kenya and 175 different samples were examined by classical morphological methods and by isoenzyme analysis using isoelectric focusing in agarose. Gels were stained for 17 different enzymes and 3 of these were used in the construction of isoenzyme profiles. The samples fell into 25 zymodemes, and no zymodeme contained more than 1 species of Taenia, indicating that isoenzyme analysis can reliably be used for the identification of species of this genus.

Animals↗
PubMed1987

Tumour necrosis factor in man: clinical and biological observations.

Eighteen patients with advanced cancer have been treated intravenously with human recombinant tumour necrosis factor (rhTNF). The drug produced febrile reactions at all doses although these were preventable by steroids and indomethacin. Doses at or above 9 x 10(5) units (400 micrograms)m-2 were associated with hypotension, abnormal liver enzymes, leucopenia and mild renal impairment in a substantial proportion of patients. RhTNF was cleared from plasma with a half life of approximately 20 minutes but non-linear pharmacokinetics lymphoma, improvements in their tumours were recorded. RhTNF was noted to produce rapid increases in serum C-reactive protein concentrations. Endogenous TNF levels were not found to be elevated in 72 cancer patients. TNF deserves further therapeutic evaluation and these observations support its biological importance as an endogenous pyrogen, mediator of acute phase protein responses, and a mediator of endotoxic shock.

Adolescent↗
PubMed1987

Abnormal expression and processing of keratins in pupoid fetus (pf/pf) and repeated epilation (Er/Er) mutant mice.

The pupoid fetus (pf) and repeated epilation (Er) mutations of mice result in a failure of epidermal differentiation in homozygotes. Expression of the epidermal keratins has been followed in pf/pf and Er/Er mice by two-dimensional gel electrophoresis, and by immunohistochemistry and Western blotting using polyclonal antibodies that are monospecific for individual keratin polypeptides. Our results show that expression of the differentiation-specific keratins (K1 and K10) is delayed in both the pf/pf and Er/Er mutants and that, when these keratins do appear later in development, they are localized in the deeper layers of the thickened mutant epidermis. Conversely, K6 and K16, two keratins found in low abundance in normal epidermis, are abundant in mutant epidermis. In newborn mutant epidermis, K6 and K16 are found to be most abundant in the outermost epidermal cells, a distribution opposite to that of K1 and K10. These findings suggest that the expression of these hyperplastic keratins in mutant mice may occur to the exclusion of the differentiation-specific keratins both during development and in newborn animals. Differentiation, and an apparently normal pattern of keratin expression, occur when whole pf/pf or Er/Er skin is grafted to normal mice. These results suggest that the pf and Er genes may be expressed systemically and that transfer of the mutant skin to a "normal" environment results in the recovery of a normal phenotype.

Animals↗
PubMed1987

The fate of embryonal-carcinoma cells in mouse blastocysts.

Double-labeled embryonal-carcinoma (ECa) cells were injected into blastocysts or incorporated into blastocysts by aggregation, and their fate after various periods of time in culture was investigated. ECa-247 cells labeled with fluorescent microscopheres were easily identified in whole blastocysts. These blastocysts were embedded in plastic, serially sectioned, and prepared for autoradiography. The 3H-thymidine label on the embryonal-carcinoma cells allowed precise localization of the cancer-derived cells. ECa-247 cells preferentially localized in the mural trophectoderm, with a few being seen in primitive endoderm and, even more rarely, in the inner cell mass. Selected autoradiograms were re-embedded and thin sectioned for transmission electron microscopy. The cancer-derived cells were found to have differentiated in accordance with their localization.

Animals↗
PubMed1987

"Campylobacter cinaedi" bacteremia: case report and laboratory findings.

"Campylobacter cinaedi" was isolated from the blood of a 29-year-old homosexual man with previously diagnosed acquired immune deficiency syndrome. Subculturing of the organism was achieved with the use of 7% lysed horse blood and 10% sheep blood agars at 37 degrees C in a microaerophilic atmosphere. Problems associated with the culturing of this organism are reviewed.

Acquired Immunodeficiency Syndrome↗