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Biomedical subjects

C Daly

Publications and source records attributed to C Daly.

At least 55 records · Page 3Linked to original sources
PubMed1998

Insertion element IS3-based PCR method for subtyping Escherichia coli O157:H7.

An Escherichia coli O157:H7 subtyping method based on PCR amplification of variable DNA sequences between the repetitive element IS3 was developed. Template DNA was prepared by boiling cells in Chelex. Two separate IS3 PCR amplifications were performed for each isolate: one with a single primer (primer IS3A) and one with two primers (primers IS3A and IS3B). The IS3 PCR subtyping method was applied to 35 epidemiologically related and unrelated E. coli O157:H7 isolates that had been previously characterized by pulsed-field gel electrophoresis (PFGE). PFGE identified 25 different subtypes (difference of one or more bands). PCR with single primer IS3A and primer pair IS3A-IS3B identified 6 and 14 different subtypes, respectively. By combining the results of the two PCR amplifications, 15 different IS3 PCR subtypes were identified. While not as sensitive as PFGE, IS3 PCR subtyping grouped all outbreak-related isolates. IS3 PCR banding patterns were reproducible between amplifications and between subcultures. IS3 PCR could serve as a simple, rapid screening method for the identification of unrelated E. coli O157:H7 isolates.

Bacterial Typing Techniques↗
PubMed1997

Post-transcriptional regulation of synaptic vesicle protein expression and the developmental control of synaptic vesicle formation.

The regulated expression of synaptic vesicle (SV) proteins during development and the assembly of these proteins into functional SVs are critical aspects of nervous system maturation. We have examined the expression patterns of four SV proteins in embryonic hippocampal neurons developing in culture and have found that increases in the levels of these proteins result primarily from post-transcriptional regulation. Synaptotagmin I, vamp 2, and synapsin I proteins are synthesized at nearly constant rates as the neurons develop. However, these proteins are relatively unstable at early times in culture and undergo a progressive increase in half-life with time, possibly as a result of an increase in the efficiency with which they are incorporated into SVs. In contrast, synaptophysin is synthesized at a very low rate at early times in culture, and its rate of synthesis increases dramatically with time. The increase in synaptophysin synthesis is not simply the result of an increase in mRNA level, but is largely attributable to an increase in the rate of translational initiation. Despite the nearly constant rates of synthesis of synaptotagmin I, vamp 2, and synapsin I, we show that the number of SVs in these developing neurons increases, and that SV proteins are more efficiently targeted to SVs at later times in culture. Our results suggest that SV production during development is not limited by the rates of transcription of genes encoding the component proteins, thus allowing control of this process by cytoplasmic mechanisms, without signaling to the nucleus.

Animals↗
PubMed1997

Personality disorder and drug use: a review.

The concept of personality disorder (PD) is more relevant in the clinical management of drug users than other approaches to personality assessment. A problem in diagnosis is separating behaviours inherent in the activity of drug misuse from true evidence of PD, especially the anti-social type (ASPD), and rating instruments vary in their ability to do this. Nevertheless, the available evidence suggests that approximately two-thirds of drug users in treatment have PD, with ASPD the most common. Studies have mainly been in opiate users, while the prevalence of PD may be lower across the range of drugs, and in non-treatment settings. PD has been found to be associated with a range of complications and adverse outcomes in drug use, including psychiatric problems, poor social functioning, dropout from treatment, and increased HIV risk behaviours and infection rates. Outcomes for ASPD individuals in methadone maintenance treatment appear reasonable, however, and it may be that early recourse to such treatment is the most practical option for many PD opiate users, a potential criticism being that this does not directly address the PD problems.

Journal Article↗
PubMed1997

Bacteraemia caused by periodontal probing.

Bacteraemia of oral origin may result in infective endocarditis in susceptible individuals. The aim of this pilot study was to investigate the occurrence of bacteraemia due to periodontal probing. Thirty patients (15 male, 15 female; mean age 42.7 years) with untreated periodontitis were investigated. All were free of significant medical disorders and none had taken antibiotics in the previous month. Prior to and immediately following periodontal probing, 20 mL of venous blood were obtained from each patient and inoculated into aerobic and anaerobic blood culture bottles and incubated. Negative bottles were monitored continuously for three weeks before being discarded. Periodontal probing consisted of measuring pockets at six points around each tooth and recording the presence or absence of bleeding. A positive bacteraemia was recorded for three of the patients prior to probing. One patient exhibited Prevotella species whilst two exhibited skin commensals. Following probing, 13 patients (43 per cent) exhibited bacteraemia of oral origin. Viridans streptococci were the most common isolates (45 per cent). No significant correlations were found between bacteraemia and the severity of periodontitis or extent of bleeding on probing. The results indicate that periodontal probing can cause bacteraemia in patients with periodontitis. It would be advisable for patients considered at risk of developing infective endocarditis to receive antibiotic prophylaxis for periodontal probing if they have radiographic evidence of periodontitis.

Adult↗
PubMed1997

The analgesic efficacy of ibuprofen in periodontal surgery: A multicentre study.

The efficacy of a non-steroidal anti-inflammatory agent, ibuprofen, was evaluated in pain control following periodontal surgery. This type of agent acts peripherally by inhibiting the release of prostaglandins and minimizing the local inflammatory response. Thus there may be an advantage in pre-treatment administration of the drug so as to delay or even prevent postoperative pain. The study was multicentre, involving a Public Hospital Periodontal Unit, two specialist periodontal practices in Sydney, NSW, and two in Canberra, ACT. One hundred and twenty-seven patients who were to undergo periodontal surgery were randomly given either two 200 mg tablets of ibuprofen or two matching placebo tablets at least 30 minutes before administration of local anaesthesia. The procedure was double blind: neither the patient nor the clinician was aware of the tablet identity. Postoperatively, all patients were given labelled ibuprofen for pain relief, but were randomly divided into two groups: As directed who were instructed to take the drug regularly for two days postoperatively, and As required, who were to take the drug only if needed for pain relief. All patients completed a diary recording quantity and time of medication, and regular assessment of pain experience utilizing a visual analogue scale. The As directed group showed no significant difference in pain experience between pre-operative and post-operative only medication, but the As required group experienced significantly less pain and requirement for medication if the ibuprofen was administered pre-operatively.

Adolescent↗
PubMed1997

Immune responses of IL-5 transgenic mice to parasites and aeroallergens.

Eosinophils have long been thought to be effectors of immunity to helminths but have also been implicated in the pathogenesis of asthma. Patterns of cytokine production in the host may influence the pathogenesis of these diseases by regulating the activities of eosinophils and other components of the immune response. Mice which constitutively over-express IL-5 have profound and life-long eosinophilia in a restricted number of tissues. Although eosinophils from IL-5 transgenics are functionally competent for a number of parameters considered to be important in inflammation, untreated animals are overtly normal and free of disease. In addition, the responses of these animals when exposed to aeroallergens and helminths present a number of apparent paradoxes. Eosinophil accumulation in tissues adjacent to major airways is rapid and extensive in transgenics exposed to the aeroallergen, but even after treatment with antigen over many months these mice show no evidence of respiratory distress or pathology. Helminth-infected IL-5 transgenics and their non-transgenic littermates develop similar inflammatory responses at mucosal sites and are comparable for a number of T cell and antibody responses, but they differ considerably in their ability to clear some parasite species. The life-cycle of Nippostrongylus brasiliensis is significantly inhibited in IL-5 transgenics, but that of Toxocara canis is not. Our results also suggest that eosinophilia and/or over-expression of IL-5 may actually impair host resistance to Schistosoma mansoni and Trichinella spiralis. The pathogenesis of diseases in which eosinophils are involved may therefore be more complex than previously thought.

Allergens↗
PubMed1996

Molecular analysis of the replication origin of the Lactococcus lactis plasmid pCJ305.

The replication origin region, ori, of the Lactococcus lactis subsp. lactis plasmid pCI305 contains three-and-one-half directly repeated 22-bp sequences and two inverted repeat sequences, IR1 and IR2. These inverted repeat sequences overlap the promoter of the repB gene, which encodes a protein (RepB) essential for plasmid replication. Gel retardation assays, using lactococcal crude cell extracts in which RepB was overproduced, were used to demonstrate that the replication protein interacts with DNA sequences within the origin region. IR1 was identified as a RepB binding site. The -35 region of the repB promoter is contained within the loop of the potential stem-loop structure of IR1, suggesting autoregulation of repB. The pCI305 RepB failed to interact with DNA sequences within the minimal replicons of nine other members of the pCI305 family of plasmids and it was concluded that this DNA-protein interaction was replicon specific. In vivo studies were performed to determine the role of the three-and-one-half copies of the 22-bp sequences. When this sequence was provided in trans on a compatible vector, it resulted in the loss of pCI305 from the cell population (incompatibility).

Bacterial Proteins↗
PubMed1996

Biotechnology of lactic acid bacteria with special reference to bacteriophage resistance.

Lactic acid bacteria play an important role in many food and feed fermentations. In recent years major advances have been made in unravelling the genetic and molecular basis of significant industrial traits of lactic acid bacteria. Bacteriophages which can infect and destroy lactic acid bacteria pose a particularly serious threat to dairy fermentations that can result in serious economic losses. Consequently, these organisms and the mechanisms by which they interact with their hosts have received much research attention. This paper reviews some of the key discoveries over the years that have led us to our current understanding of bacteriophages themselves and the means by which their disruptive influence may be minimized.

Bacteriophages↗
PubMed1996

mdr1 ribozyme mediated reversal of the multi-drug resistant phenotype in human lung cell lines.

An mdr1 hammerhead was introduced into two adriamycin-selected multi-drug resistant human lung cell lines both of which over-express p-glycoprotein. Expression of the ribozyme resulted in a decrease in mdr1 mRNA expression and an increase in drug sensitivity in both cell lines. This would suggest that the use of specific ribozymes may represent an effective and specific approach in order to restore cellular sensitivity towards anti-cancer drugs.

ATP Binding Cassette Transporter, Subfamily B, Mem↗
PubMed1996

AbiG, a genotypically novel abortive infection mechanism encoded by plasmid pCI750 of Lactococcus lactis subsp. cremoris UC653.

AbiG is an abortive infection (Abi) mechanism encoded by the conjugative plasmid pCI750 originally isolated from Lactococcus lactis subsp. cremoris UC653. Insensitivity conferred by this Abi manifested itself as complete resistance to phi 712 (936 phage species) with only partial resistance to phi c2 (c2 species). The mechanism did not inhibit phage DNA replication. The smallest subclone of pCI750 which expressed the Abi phenotype contained a 3.5-kb insert which encoded two potential open reading frames. abiGi (750 bp) and abiGii (1,194 bp) were separated by 2 bp and appeared to share a single promoter upstream of abiGi. These open reading frames showed no significant homology to sequences of either the DNA or protein databases; however, they did exhibit the typical low G+C content (29 and 27%, respectively) characteristic of lactococcal abi genes. In fact, the G+C content of a 7.0-kb fragment incorporating the abiG locus was 30%, which may suggest horizontal gene transfer from a species of low G+C content. In this context, it is notable that remnants of IS elements were observed throughout this 7.0-kb region.

Amino Acid Sequence↗
PubMed1996

Characteristics and outcome of anti-glomerular basement membrane disease: a single-center experience.

Over the last 16 years we have treated 40 patients with a renal pathological diagnosis of anti-glomerular basement membrane (anti-GBM) disease. The age of presentation ranged from 18 years to 76. Males and females were equally affected. The most common presenting symptoms were anorexia and uremia. Fifty percent of the patients were oliguric at presentation and required dialysis within 24 h, while the mean serum creatinine (Cr) at presentation was 5.1 +/- 6.8 mg/dL. Sixty-two percent of the patients demonstrated evidence of pulmonary involvement. Hematuria was universally present and was macroscopic in 35% of cases. Eight-two percent of the biopsies demonstrated greater than 80% crescents. Eight patients retained independent renal function after immunosuppression with cyclophosphamide, prednisone, and plasmapheresis. No patient who presented with a Cr greater than 5 mg/dL retained renal function. Using a logistic regression model the only clinical, biochemical, or pathological factors at presentation that significantly predicted eventual need for dialysis were the serum creatinine and percentage of glomeruli with crescents. Ten patients underwent cadaveric renal transplantation, and 7 have a functioning graft for a mean of 8.2 years. None have shown evidence of recurrence of anti-GBM disease in the graft. We conclude that anti-GBM disease is an important cause of renal failure and that its prognosis is directly related to the degree of renal failure at presentation. Efforts need to be made to diagnose this condition earlier in its natural history if its prognosis is to be improved.

Adolescent↗
PubMed1995

Characterization of specific DNA-binding factors activated by double-stranded RNA as positive regulators of interferon alpha/beta-stimulated genes.

Viral infection results in transcriptional activation of the cellular interferon alpha/beta-stimulated genes (ISGs) independent of the autocrine action of interferon alpha/beta (IFN-alpha/beta). Induction of ISG expression by virus appears to be mediated through production of viral double-stranded RNA (dsRNA). Previously, we identified two novel dsRNA-activated factors (DRAFs) that bind to the interferon-stimulated response element (ISRE), the DNA sequence that mediates transcriptional activation by IFN-alpha/beta. In this report we define sequences that flank the classical ISRE to be necessary for DRAF1 binding. More significantly, it is shown that the sequences required to bind DRAF1 correlate with the ability to mediate ISG induction by virus. These results strongly suggest that DRAF1 is a positive regulator of ISG transcription. DRAF1 is shown to bind selectively to the promoters of those ISGs which are strongly induced by viral infection, again suggesting the functional significance of this factor. UV cross-linking experiments indicate that DRAF1 and DRAF2 share a common DNA-binding subunit of approximately 70 kDa which is referred to as the DRAF binding component (DRAFB). DRAFB is shown to preexist in the cytoplasm of unstimulated cells. Consistent with this observation, both DRAF1 and DRAF2 are activated in the cytoplasm prior to nuclear translocation.

Base Sequence↗
PubMed1995

Identification and characterization of the type-IVA cyclic AMP-specific phosphodiesterase RD1 as a membrane-bound protein expressed in cerebellum.

An antiserum was generated against a dodecapeptide whose sequence is found at the C-terminus of a cyclic AMP (cAMP)-specific, type-IVA phosphodiesterase encoded by the rat 'dunc-like' cyclic AMP phosphodiesterase (RD1) cDNA. This antiserum identified a single approximately 73 kDa protein species upon immunoblotting of cerebellum homogenates. This species co-migrated upon SDS/PAGE with a single immunoreactive species observed in COS cells transfected with the cDNA for RD1. Native RD1 in cerebellum was found to be predominantly (approximately 93%) membrane-associated and could be found in isolated synaptosome populations, in particular those enriched in post-synaptic densities. Fractionation of lysed synaptosomes on sucrose density gradients identified RD1 as co-migrating with the plasma membrane marker 5'-nucleotidase. Laser scanning confocal and digital deconvolution immunofluorescence studies done on intact COS cells transfected with RD1 cDNA showed RD1 to be predominantly localized to plasma membranes but also associated with the Golgi apparatus and intracellular vesicles. RD1-specific antisera immunoprecipitated phosphodiesterase activity from solubilized cerebellum membranes. This activity had the characteristics expected of the type-IV cAMP phosphodiesterase RD1 in that it was cAMP specific, exhibited a low Km cAMP of 2.3 microM, high sensitivity to inhibition by 4-[3-(cyclopentoxyl)-4-methoxyphenyl]-2-pyrrolidone (rolipram) (Ki approximately 0.7 microM) and was unaffected by Ca2+/calmodulin and low concentrations of cyclic GMP. The phosphodiesterase activities of RD1 solubilized from both cerebellum and transfected COS cell membranes showed identical first-order thermal denaturation kinetics at 50 degrees C. Native RD1 from cerebellum was shown to be an integral protein in that it was solubilized using the non-ionic detergent Triton X-100 but not by either re-homogenization or high NaCl concentrations. The observation that hydroxylamine was unable to cause the release of RD1 from either cerebellum or COS membranes and that [3H]palmitate was not incorporated into the RD1 protein immunoprecipitated from COS cells transfected with RD1 cDNA, indicated that RD1 was not anchored by N-terminal acylation. The engineered deletion of the 25 residues forming the unique N-terminal domain of RD1 caused both a profound increase in its activity (approximately 2-fold increase in Vmax) and a profound change in intracellular distribution. Thus, immunofluorescence studies identified the N-terminal truncated species as occurring exclusively ion the cytosol of transfected COS cells. The cDNA for RD1 thus appears to encode a native full-length type-IVA phosphodiesterase that is expressed in cerebellum.(ABSTRACT TRUNCATED AT 400 WORDS)

3',5'-Cyclic-AMP Phosphodiesterases↗