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Biomedical subjects

D Hughes

Publications and source records attributed to D Hughes.

At least 55 records · Page 3Linked to original sources
PubMed2001

Phylogenetic characterization of epibiotic bacteria in the accessory nidamental gland and egg capsules of the squid Loligo pealei (Cephalopoda:Loliginidae).

Sexually mature female squid Loligo pealei harbour dense bacterial communities in their accessory nidamental glands (ANGs) and in their egg capsules (ECs). This study describes a molecular approach using the 16S rRNA gene (rDNA) to identify bacterial populations within the ANG and the ECs of the North Atlantic squid species L. pealei. Fluorescent in situ hybridization (FISH) and 16S rDNA analysis showed that predominantly alpha- and, to a lesser extent, gamma-proteobacteria were the predominant components of the ANG and EC bacterial communities. Sequencing results showed the presence of alpha-proteobacterial populations affiliated with the Roseobacter group and additional deep-branching alpha-proteobacterial lineages. In contrast, isolates from the ANG and ECs contained only a few alpha-proteobacteria of the Roseobacter group compared with several gamma-proteobacterial isolates, mostly Shewanella and Pseudoalteromonas species. Most of the ANG-associated bacterial populations were also found within the ECs of L. pealei. The molecular approach allowed the visualization of alpha-proteobacteria as major constituents of a bacterial symbiosis within the reproductive system of the Loliginidae.

Anaerobiosis↗
PubMed2001

Intrathecal ropivacaine or bupivacaine with fentanyl for labour.

Combined spinal-epidural (CSE) is widely used to provide pain relief in labour while minimizing motor blockade. Aiming to further reduce associated motor weakness, we compared ropivacaine 2.5 mg in the intrathecal injection with a standard bupivacaine CSE in a double-blind study. Forty women were randomized to receive either bupivacaine 2.5 mg or ropivacaine 2.5 mg intrathecally, both with fentanyl 0.025 mg. There were no significant differences between the groups regarding the onset, duration or quality of analgesia or the level of sensory block attained. Forty per cent of the women (8/20) receiving bupivacaine developed detectable motor block compared with only 5% (1/20) in the ropivacaine group (P<0.05). Vibration sense was impaired in one woman in each group. Adverse effects did not differ between groups. We conclude that intrathecal ropivacaine 2.5 mg in combination with fentanyl 0.025 mg as part of a CSE technique provides rapid and safe analgesia for labour as effective as that achieved with bupivacaine 2.5 mg and with significantly less motor block.

Adolescent↗
PubMed2001

Targeting expression of hsp70i to discrete neuronal populations using the Lmo-1 promoter: assessment of the neuroprotective effects of hsp70i in vivo and in vitro.

Transgenic technology provides a powerful means of studying gene regulation and specific gene function with complex mammalian systems. In this study, the authors exploited the specific and discrete neuronal expression pattern mediated by promoter 1 of the Lmo-1 gene to study the neuroprotective effects of the inducible form of heat shock protein 70kD (hsp70i) in primary hippocampal cultures in a mouse model of global cerebral ischemia. Targeting expression of hsp70i to hippocampal neurons protected these cells significantly from toxic levels of glutamate and oxidative stress (for example, exposure to 10 micromol/L free iron produced a 26% increase in lactate dehydrogenase release from neurons cultured from wild-type mice, but a 7% increase in neurons cultured from hsp70i transgenic mice). Bilateral carotid occlusion (25 minutes) produced significantly less neuronal damage in the caudate nucleus and posterior thalamus in hsp70i transgenic mice than in wild-type littermates (for example, 21% +/- 9.3% and 12.5% +/- 9.0% neuronal damage in lateral caudate nucleus of wild-type and hsp70i transgenic mice, respectively, P < 0.05). The current study highlights the utility of targeted expression of transgenes of interest in cerebral ischemia and demonstrates that expression of hsp70i alone is sufficient to mediate the protection of primary neurons from denaturing stress and that expression of human hsp70i in vivo plays crucial role in determining the fate of neurons after ischemic challenge.

Animals↗
PubMed2001

Disappointing sensitivity of endoscopic markers for villous atrophy in a high-risk population: implications for celiac disease diagnosis during routine endoscopy.

OBJECTIVE: Endoscopic markers of duodenal villous atrophy (VA) can facilitate diagnosis of celiac disease during routine upper GI endoscopy. We studied their sensitivity for VA in a large series of patients undergoing GI endoscopy specifically for duodenal biopsy. Poor sensitivity in this setting would have significant and adverse implications for their performance during routine endoscopy. METHODS: All patients with VA on duodenal biopsy performed for positive serum endomysial antibody (EmA) and/or clinical features suggestive of celiac disease were included. The second part of duodenum was inspected carefully for endoscopic markers using videogastroscopes. RESULTS: Of 129 patients studied, 99 (77%) had at least one endoscopic markers. The most commonly seen marker were a mosaic pattern mucosa (68 patients, 53%) and scalloping of duodenal folds (74 patients, 57%). The prevalence of markers was significantly lower for partial VA (15 of 26 patients, 58%) than for subtotal or total VA (84 of 103 patients, 82%) (p < 0.02). CONCLUSIONS: Endoscopic markers have disappointing sensitivity even in a population at high risk of celiac disease, particularly for partial VA. Their performance may be even poorer in an unselected dyspeptic population. Although they may help improve diagnosis rates among patients with nonspecific dyspeptic symptoms, many patients, particularly those with milder enteropathy, will be missed. As celiac disease is an important cause of dyspepsia, consideration should be given to serological screening to further improve diagnosis rates, as few centers will have the resources to routinely biopsy all patients.

Adolescent↗
PubMed2001

Evaluation of a point-of-care coagulation analyzer for measurement of prothrombin time, activated partial thromboplastin time, and activated clotting time in dogs.

OBJECTIVE: To evaluate a point-of-care coagulation analyzer (PCCA) in dogs with coagulopathies and healthy dogs. ANIMALS: 27 healthy and 32 diseased dogs with and without evidence of bleeding. PROCEDURE: Prothrombin time (PT), activated partial thromboplastin time (aPTT), and activated clotting time (ACT) were determined, using a PCCA and standard methods. RESULTS: Using the PCCA, mean (+/- SD) PT of citrated whole blood (CWB) from healthy dogs was 14.5+/-1.2 seconds, whereas PT of nonanticoagulated whole blood (NAWB) was 10.4+/-0.5 seconds. Activated partial thromboplastin time using CWB was 86.4+/-6.9 seconds, whereas aPTT was 71.2+/-6.7 seconds using NAWB. Reference ranges for PT and aPTT using CWB were 12.2 to 16.8 seconds and 72.5 to 100.3 seconds, respectively. Activated clotting time in NAWB was 71+/-11.8 seconds. Agreement with standard PT and aPTT methods using citrated plasma was good (overall agreement was 93% for PT and 87.5% for aPTT in CWB). Comparing CWB by the PCCA and conventional coagulation methods using citrated plasma, sensitivity and specificity were 85.7 and 95.5% for PT and 100 and 82.9% for aPTT, respectively. Overall agreement between the PCCA using NAWB and the clinical laboratory was 73% for PT and 88% for aPTT. Using NAWB for the PCCA and citrated plasma for conventional methods, sensitivity and specificity was 85.7 and 68.4% for PT and 86.7 and 88.9% for aPTT, respectively. CONCLUSIONS AND CLINICAL RELEVANCE: The PCCA detected intrinsic, extrinsic, and common pathway abnormalities in a similar fashion to clinical laboratory tests.

Animals↗
PubMed2000

Evaluating genome dynamics: the constraints on rearrangements within bacterial genomes.

Inversions and translocations distinguish the genomes of closely related bacterial species, but most of these rearrangements preserve the relationship between the rearranged fragments and the axis of chromosome replication. Within species, such rearrangements are found less frequently, except in the case of clinical isolates of human pathogens, where rearrangements are very frequent.

Bacteria↗
PubMed2000

Structure of a mutant EF-G reveals domain III and possibly the fusidic acid binding site.

The crystal structure of Thermus thermophilus elongation factor G (EF-G) carrying the point mutation His573Ala was determined at a resolution of 2.8 A. The mutant has a more closed structure than that previously reported for wild-type EF-G. This is obtained by a 10 degrees rigid rotation of domains III, IV and V with regard to domains I and II. This rotation results in a displacement of the tip of domain IV by approximately 9 A. The structure of domain III is now fully visible and reveals the double split beta-alpha-beta motif also observed for EF-G domain V and for several ribosomal proteins. A large number of fusidic acid resistant mutations found in domain III have now been possible to locate. Possible locations for the effector loop and a possible binding site for fusidic acid are discussed in relation to some of the fusidic acid resistant mutations.

Amino Acid Motifs↗
PubMed2000

Hydrogen iodide-promoted reduction of beta-chlorovinamidinium salts

HI cleanly reduced chlorovinamidinium salts to the vinamidinium salt in essentially quantitative assay yield and 55-85% isolated yield following recrystallization. The reaction proceeds via protonation of the beta-carbon atom of the vinamidinium and dechlorination via the formation of I-Cl.

Journal Article↗
PubMed2000

Chronic atrophic gastritis and Helicobacter pylori infection among Japanese Americans in Seattle.

Gastric cancer is still a major cause of mortality due to cancer worldwide. The most common type of gastric cancer is intestinal type carcinoma, which usually occurs in stomachs containing chronic atrophic gastritis. Individuals with chronic atrophic gastritis are considered to be at increased risk for developing intestinal type carcinoma of the stomach. To examine the association between chronic atrophic gastritis and other gastric cancer risk factors, a cross-sectional study was conducted using serum samples and questionnaire information collected from 776 persons of full Japanese ancestry in the greater Seattle area in 1994. The presence of chronic atrophic gastritis and Helicobacter pylori infection was determined by measurement of serum pepsinogen levels and H. pylori antibodies, respectively. Based on multiple logistic regression, the significant predictors of chronic atrophic gastritis were age over 50 years, H. pylori infection, and 20 years or more lived in Japan. Alcohol consumption, smoking, prior peptic ulcer, and history of gastric cancer in parents were not significantly associated with chronic atrophic gastritis. The results imply that H. pylori infection since earlier life and other unknown exposure factors in Japan might have played an important role in the development of chronic atrophic gastritis.

Adult↗
PubMed2000

Co-evolution of the tuf genes links gene conversion with the generation of chromosomal inversions.

The tufA and tufB genes in Salmonella typhimurium co-evolve by recombination and exchange of genetic material. A model is presented which predicts that co-evolution is achieved by gene conversions and chromosomal inversions. Analysis of recombinants reveals that conversion and inversion each occur with similar rates and each depends on RecBCD activity. The model predicts sequence structures for different classes of post-recombination tuf genes. Sequence analysis reveals the presence of each of these structures and classes, with a predicted bias in the absence of mismatch repair. An implication of these data is that co-evolution of gene families can be linked with the generation of chromosomal rearrangements.

Alleles↗
PubMed2000

Effects of environment on compensatory mutations to ameliorate costs of antibiotic resistance.

Most types of antibiotic resistance impose a biological cost on bacterial fitness. These costs can be compensated, usually without loss of resistance, by second-site mutations during the evolution of the resistant bacteria in an experimental host or in a laboratory medium. Different fitness-compensating mutations were selected depending on whether the bacteria evolved through serial passage in mice or in a laboratory medium. This difference in mutation spectra was caused by either a growth condition-specific formation or selection of the compensated mutants. These results suggest that bacterial evolution to reduce the costs of antibiotic resistance can take different trajectories within and outside a host.

Adaptation, Physiological↗
PubMed2000

A deletion on chromosome 4 cosegregates with the whirler deafness mutation: exclusion of Orm1 as a candidate.

Whirler (wi) mice display profound deafness and a head-tossing and circling phenotype, showing an autosomal recessive mode of inheritance. The wi mutation has been shown to map close to the Orm gene cluster on mouse Chromosome (Chr) 4. We have, therefore, investigated the Orm loci as candidates for the whirler gene. Detailed mapping and analysis of the Orm gene cluster in both normal and whirler mice indicates the presence of a <48-kb deletion in whirler mice that disrupts the Orm1 locus. The Orm1 locus is also deleted in the CE/J mouse strain, and we discuss the candidature of Orm1 for the whirler gene.

Animals↗
PubMed2000

Emergency vascular access.

Establishing and maintaining vascular access is often vital to the preoperative, intraoperative, and postoperative management of the small animal emergency surgical patient. Vascular access may be used for the delivery of crystalloids, colloids, blood components, medications, and anesthetic or sedative agents. It can also facilitate venous and arterial blood sampling and allow direct measurement of arterial and venous pressures. The small animal emergency and critical care veterinarian should have a thorough knowledge of vascular access techniques, including peripheral and central venous catheterization, intraosseous, and arterial access. Competence in percutaneous, percutaneous facilitative, and surgical cutdown approaches should ensure that vascular access can always be established in the critically ill patient.

Animals↗
PubMed2000

Diagnosis and management of peritonitis.

Peritonitis is a clinical syndrome rather than a definitive diagnosis and, as such, the underlying cause must be identified. Many potential causes exist, and peritonitis may be classified as primary or secondary, local or diffuse, acute or chronic, or according to the causative agent. Peritonitis is one of the most common initiators of the systemic inflammatory response syndrome faced by the small animal practitioner. Because systemic inflammatory response syndrome is such a devastating disease process, aggressive stabilization, rapid definitive diagnosis, and prompt surgical and medical treatment are vital for optimizing outcome.

Animals↗
PubMed2000

Talking contracts and taking care: managers and professionals in the British National Health Service internal market.

This paper draws on audio-recordings of a Health Authority's contract monitoring meetings with hospital providers to examine the nature of interactions between managers and clinical professionals in the British National Health Service internal market. It describes how managers and professionals arrive at a working division of labour, which acknowledges their respective spheres of expertise, but also leaves a space where definitions are contested. There is an interplay of competing managerial and professional discourses which construct problems and proposed solutions in fundamentally non-commensurable ways. Yet only rarely do managers or professionals mount challenges in ways that bring them on to the territory of the other group; rather each group seeks to frame problems to mesh with its special domain of competence. Managers seek to push back the boundaries of professional control by constructing a language and set of practices which will govern the contracting process. But they remain reliant on professionals to mediate between the requirements of contracting and the realities of clinical work. Clinical arguments continue to have high perceived legitimacy for managers, and will often be taken up by hospital managers in negotiations with their Health Authority counterparts. It is argued that the dependency of managers on professionals to make the contracting system work, taken together with the continued social and cultural authority of senior medical consultants, limits managers' ability to control professionals.

Contract Services↗