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Biomedical subjects

M O'Regan

Publications and source records attributed to M O'Regan.

At least 19 recordsLinked to original sources
PubMed1998

Antimony in blood and urine of infants.

AIM: To establish a reference range for antimony in the serum and urine of infants in the first year of life. METHODS: 100 infants were selected randomly from the population. Each infant had a single blood and urine sample taken. Antimony was assayed using inductively coupled plasma mass spectrometry. RESULTS: The reference range for antimony in the serum of infants in the first year of life was established as 0.09-0.25 microgram/l. The upper 95% centile for urinary antimony, corrected for creatinine, in the same population was 2.6 ng/mg creatinine. There was a very weak correlation between the serum and urine concentrations. CONCLUSIONS: This study confirms the presence of low concentrations of antimony in the serum and urine of healthy infants.

Age Factors↗
PubMed1997

Reconstructive surgery of the urethra: a pilot study in the rabbit on the use of hyaluronan benzyl ester (Hyaff-11) biodegradable grafts.

We investigated the outcome of reconstructive surgery of the urethra through guides composed of a novel biodegradable and highly biocompatible polymer, Hyaff-11. A tract of about 1.5 cm of the rabbit pendulous urethra was totally resected and replaced by a Hyaff-11 tubular graft. Eleven animals were analysed at each of the time points ranging from 7 days to 4 weeks following surgery. Histological and radiological evaluation showed a satisfactory remodelling of the neo-urethra around the implant. The regenerated connective tissue connected both urethral stumps within the first 7 days. On postoperative week 3, the Hyaff-11 guide had disappeared. At the 4-week time point the retrograde urethrogram showed a good distensibility of the neourethra. The regenerated stroma consisted of fibroblastic cells, and collagenous and elastic fibres. The neo-epithelium was pluristratified and exhibited cells of the cuboidal type.

Animals↗
PubMed1996

Improved delivery of biocontrol Pseudomonas and their antifungal metabolites using alginate polymers.

Alginate polymer was evaluated as a carrier for seed inoculation with a genetically modified strain Pseudomonas fluorescens F113LacZY, which protects sugar-beet against Pythium-mediated damping-off. F113LacZY survived in alginate beads at 5 log10 CFU/bead or higher counts for 8 weeks of storage, regardless of the conditions of incubation. In plant inoculation experiments, colonisation of the growing area of the root by F113LacZY, derived from alginate beads placed in the soil next to the seed or from an alginate coating around the seeds, was improved compared with application of just free cells of the strain. F113LacZY trapped in alginate beads was an effective producer of antifungal phloroglucinols as indicated by direct HPLC quantification of phloroglucinols and in vitro inhibition of both the indicator bacterium Bacillus subtilis A1 and the pathogenic fungus Pythium ultimum. Alginate polymer represents a promising carrier for the delivery of biocontrol inoculants for root colonisation and production of antifungal metabolites.

Alginates↗
PubMed1996

Quantitative assessment of the tissue response to films of hyaluronan derivatives.

The aim of this study was to evaluate the in vivo response following implantation into a rat model of three innovative hyaluronan derivatives for clinical use: HYAFF 7, HYAFF 11 and HYAFF 11p75 (respectively, the 100% ethyl ester, 100% and 75% benzyl esters). The tissue reaction evoked by films of these new biomaterials implanted into the dorsolumbar musculature of rats was assessed quantitatively using a well established technique based upon an image analysis system. The number of inflammatory cells present and the patterns of cell distribution around the implant up to a distance of 642 microns were examined at different time periods after implantation. Since a well-delineated tissue-material interface was needed for this type of investigation, it was not possible to apply image analysis to sections once dissolution of the implanted materials had begun. Films of both the total esters, HYAFF 7 and HYAFF 11, were found to undergo a slow dissolution process and, after a month, films of these materials were still present at the site of implantation. Differences in response to the two materials were observed only during the first two weeks, particularly with respect to neutrophil distribution and total cellularity. HYAFF 7 was found to be more reactive, with higher numbers of neutrophils near the surface of the implant than HYAFF 11. Thereafter, the differences between the two materials were minimal and owing mainly to a faster dissolution of HYAFF 7 films. After 3 and 5 months, considerable degradation of films of both total esters had occurred. Significant quantities of material appeared inside numerous macrophages with an ED1-positive phenotype. Only a very thin layer of fibrous connective tissue, indicative of low reactivity, was found to surround the site of implantation, separating the dissolved material and the phagocytic cells from healthy muscular tissue. ED2-positive macrophages were primarily confined within the lining connective tissue. The partial benzyl ester, HYAFF 11p75, showed a different behaviour. In fact, evidence of film dissolution was already present a week after the implantation. After two weeks, the implanted films were completely dissolved and numerous ED1-positive macrophages phagocytosing the material were observed at the site of implantation. Therefore, in agreement with previous in vitro studies, which showed a greater susceptibility to degradation of hyaluronan derivatives with lower percentage of esterification, HYAFF 11p75 underwent resorption faster than the corresponding total ester.

Animals↗
PubMed1996

Overexpression, one-step purification and characterization of UDP-glucose dehydrogenase and UDP-N-acetylglucosamine pyrophosphorylase.

Two enzymes of the Leloir pathway, UDP-GlcNAc pyrophosphorylase and UDP-Glc dehydrogenase, which are involved in the synthesis of activated sugar nucleotides have been cloned, overexpressed in Escherichia coli, and purified to homogeneity in only one step by chelation-affinity chromatography. The gene KfaC of E. coli K5 was thus demonstrated to encode UDP-Glc DH. Some properties of the cloned enzymes, such as stability, pH dependence, and substrate kinetics, were studied in order to facilitate the use of these enzymes in carbohydrate synthesis, especially in the synthesis of hyaluronic acid.

Amino Acid Sequence↗
PubMed1996

Antioxidant effects of hyaluronan and its alpha-methyl-prednisolone derivative in chondrocyte and cartilage cultures.

OBJECTIVE: To compare hyaluronan and its alpha-methyl prednisolone derivative (HYC-141) with respect to their potential to directly cause tissue damage and to protect tissues from attack by reactive oxygen species. METHODS: Cartilage samples and chondrocytes were isolated from 15-day chick embryos and were exposed to enzyme-based and activated inflammatory cell-free radical generating systems in the presence of varying concentrations of alpha-methyl prednisolone, hyaluronan, and HYC-141. Tissue and cell vitality was measured by determining the incorporation of radioactive sulphate into newly synthesized glycosaminoglycans. RESULTS: Only alpha-methyl prednisolone caused a significant decrease in biosynthetic activity. All the tested substances were capable, to some extent, of protecting tissues and cells from damage by reactive oxygen species; HYC-141 demonstrated the greatest protective effect. CONCLUSION: These data suggest that HYC-141 may possess certain advantages over the individual component molecules in the local treatment of arthropathies.

Animals↗
PubMed1996

Quality of life following percutaneous transluminal angioplasty for claudication.

OBJECTIVE: To determine quality of life in claudicants before and after percutaneous transluminal angioplasty (PTA). DESIGN: Prospective study using EuroQuol questionnaire and visual analogue scales. SETTING: District general hospital. MATERIAL: Twenty-nine patients undergoing successful PTA. RESULTS: Before PTA patients showed a significantly lower EuroQuol score compared with the normal population. There was also marked impairment of patients usual activities, mobility and perceived health state. Following successful PTA the EuroQuol score, perceived health state, mobility, usual activities, pain and discomfort and mental state were all significantly improved. CONCLUSIONS: Intermittent claudication impairs quality of life. Following successful PTA there is significant improvement in symptoms and in general health.

Aged↗
PubMed1995

Oral versus intravenous antibiotics for community acquired lower respiratory tract infection in a general hospital: open, randomised controlled trial.

OBJECTIVE: To see whether there is a difference in outcome between patients treated with oral and intravenous antibiotics for lower respiratory tract infection. DESIGN: Open controlled trial in patients admitted consecutively and randomised to treatment with either oral co-amoxiclav, intravenous followed by oral co-amoxiclav, or intravenous followed by oral cephalosporins. SETTING: Large general hospital in Dublin. PATIENTS: 541 patients admitted for lower respiratory tract infection during one year. Patients represented 87% of admissions with the diagnosis and excluded those who were immunocompromised and patients with severe life threatening infection. MAIN OUTCOME MEASURES: Cure, partial cure, extended antibiotic treatment, change of antibiotic, death, and cost and duration of hospital stay. RESULTS: There were no significant differences between the groups in clinical outcome or mortality (6%). However, patients randomised to oral co-amoxiclav had a significantly shorter hospital stay than the two groups given intravenous antibiotic (median 6 v 7 and 9 days respectively). In addition, oral antibiotics were cheaper, easier to administer, and if used routinely in the 800 or so patients admitted annually would lead to savings of around 176,000 pounds a year. CONCLUSIONS: Oral antibiotics in community acquired lower respiratory tract infection are at least as efficacious as intraveous therapy. Their use reduces labour and equipment costs and may lead to earlier discharge from hospital.

Administration, Oral↗
PubMed1995

Population biology of Pomphorhynchus laevis in brown trout from two lakes in the west of Ireland.

Since Ireland is the only country in which Pomphorhynchus laevis (Acanthocephala) uses brown trout (Salmo trutta) as its preferred definitive host, the population biology of the parasite in this host was investigated thus enabling a comparison to be made with data collected on P. laevis from other hosts, particularly the cyprinids, chub and barbel. Over a period of 12 months, 549 brown trout were caught from two lakes, Lough Feeagh and Bunaveela Lake, in the Burrishoole River system, Co. Mayo, Ireland. The parasite component community was dominated by a single species, P. laevis. Fifty eight percent of the trout sample were infected with the acanthocephalan and the mean abundance (+/- SD) was 3.1 +/- 5.1 The relationships between the prevalence and abundance of P. laevis and season and site of host capture and host age and sex were explored. As single factors one of these parameters emerged as significant contributions to changes in parasite abundance although some interaction terms proved to the significant. A random sample of over 700 P. laevis parasites were subjected to further investigation and their size, position in the intestine and maturity status are described. Parasites attained an average weight of 7 mg and occupied the posteriad positions within the fish intestine (77%). Parasites from this sample of Irish brown trout attained a similar average size to those found in chub and barbel from England. 42.3% of the total parasites examined contained ovarian balls only and 17% contained fully mature acanthors. Therefore only a moderate proportion of female worms contained mature acanthors in these trout whereas the majority of worms recovered from a sample of chub were gravid. Utilizing a logistic regression model, parasite size, season, and site of host capture emerged as particularly significant factors which contribute to whether a parasite contains mature eggs.

Acanthocephala↗
PubMed1994

Molecular mechanisms and genetics of hyaluronan biosynthesis.

Hyaluronan is an extremely important polysaccharide from both the biological and commercial points of view. This review summarizes the present state of the art concerning the polymer and our understanding of the molecular mechanisms of its synthesis with emphasis on the implications of this understanding for polysaccharide engineering of hyaluronan.

Bacterial Proteins↗
PubMed1994

The comparison of type of incision for transperitoneal abdominal aortic surgery based on postoperative respiratory complications and morbidity.

Equal access to the abdominal aorta can be attained through midline and transverse abdominal incisions. The surgical literature suggests that transverse incisions cause less postoperative pain and morbidity. Fifty patients (10 females and 40 males, mean age 67 years) undergoing abdominal aortic surgery were randomised to a midline (n = 25) or transverse (n = 25) incision. All patients were evaluated preoperatively and postoperatively for seven days. Changes in pulmonary function (FVC and FEV1), time to open and close the incision, analgesia used (morphine mg/kg/h), clinical or X-ray evidence of chest infection, and the duration of ICU stay were recorded. In the transverse group there was a reduction in the incidence of chest complications (20% vs. 28%, p = ns) and these incisions took longer to open (13.9 +/- 4.6 vs. 9.9 +/- 5.1, p < 0.05), but overall there was no significant difference between any other parameter in the two groups. Our results show no statistically significant difference in morbidity or analgesia consumption following transverse or midline abdominal incisions and we conclude that the type of incision used can be left to the surgeon's preference.

Aged↗
PubMed1994

Chorionic villous haemorrhage is associated with retroplacental haemorrhage.

OBJECTIVE: To examine the frequency of occurrence of chorionic villous haemorrhage in placentas with retroplacental haemorrhage, and to discuss the pathogenesis of these conditions. DESIGN: A retrospective study using histological sections of formalin-fixed, paraffin-embedded placental tissue stained with haematoxylin and eosin. SETTING: Department of Histopathology, Rotunda Hospital, Dublin. SUBJECTS: Sixty cases of retroplacental haemorrhage, 34 cases of chorioamnionitis, and 24 histologically normal placentas. MAIN OUTCOME MEASUREMENT: Presence or absence of chorionic villous haemorrhage. RESULTS: Chorionic villous haemorrhage was present in 31 of 60 cases of retroplacental haemorrhage (51%), one of 34 cases of chorioamnionitis (2.9%) and in no normal placentas. CONCLUSIONS: It is postulated that chorionic villous haemorrhage reflects a disturbance of fetal vascular dynamics and precedes retroplacental haemorrhage. Such a disturbance could trigger the events leading to abruption.

Chorioamnionitis↗
PubMed1993

Hyaluronate synthase: cloning and sequencing of the gene from Streptococcus sp.

The complete nucleotide sequence of hyaluronate synthase from Streptococcus sp. and its flanking regions is presented. The gene locus was designated has. Southern-blotting results suggested that the gene was conserved in hyaluronate-producing streptococci. A putative translation-initiation codon was identified and the open reading frame consists of 1566 bp, specifying a protein of 56 kDa. Sequences resembling the promoter and ribosome-binding site of Gram-positive organisms are found upstream of the synthase. The predicted amino-acid sequence reveals the presence of a 35-residue signal peptide. The sequence has some similarity to bacterial peptide-binding proteins.

Amino Acid Sequence↗
PubMed1993

A quantitative study of the perikaryon and the basal dendritic tree in rat hippocampus (CA1) pyramids following different experimental procedures.

A quantitative study of perikaryon and basal dendritic branching of hippocampal (CA1) neurons in male Wistar rats, in three experimental groups is reported. The groups of animals were exposed to treatment with either a tricyclic antidepressant, or a saline control injection or no handling. The hippocampal tissue was studied following Golgi-Kopsch impregnation and comparative measurements made using semi-automatic image analysis and light microscopy. Measurements of the extent of basal dendritic branching showed a significant difference (p < 0.01) between the saline-injected and unhandled control groups. The drug-injected and saline-injected groups had similar values although the drug-injected group did not prove to be significantly different from the unhandled controls. No statistical difference was noted in the perikaryon size of the three experimental groups. These results are discussed with reference to the effects of sensory stimulation on neuronal plasticity.

Animals↗
PubMed1993

Effect of pre-operative antibiotic treatment on the bacterial content of the tonsil.

The impact of 7 days pre-tonsillectomy antibiotics on the aerobic bacterial content of the tonsil was studied in 70 consecutive patients. One group received no antibiotic, one group received pre-operative amoxycillin and the final group, pre-operative cefaclor. The qualitative bacteriology was similar in the three groups Haemophilus influenzae was the predominant isolate present in the centre ('core') of the resected tonsil. Similar numbers of beta-lactamase producers including H. influenzae and Straphylococcus aureus were found in all three groups. Quantitative bacteriology of the tonsil core demonstrated that there was a significant reduction in core tonsil pathogens associated with antibiotic therapy. The most statistically significant difference was between the untreated control group and the cefaclor treated group. We conclude that in patients with established recurrent acute tonsillitis, oral antibiotics penetrate the diseased tonsil and influence the predominant core aerobic microflora.

Adolescent↗