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Biomedical subjects

A Coffey

Publications and source records attributed to A Coffey.

35 records · Page 2Linked to original sources
PubMed1996

The incidence of bacteremia after orthodontic banding.

This investigation assessed the incidence of bacteremia after orthodontic banding. Thirty adult volunteers with good oral health, who were not at risk from bacterial endocarditis, were included in this study. An orthodontic band was placed on a first molar of each subject. Venous blood samples were taken before, and 1 to 2 minutes after the molar band was fitted. Microbiologic tests performed on the blood samples revealed a comparatively low incidence of bacteremia (10%) after orthodontic banding.

Adult↗
PubMed1996

Influence of environmental parameters on phosphatidylcholine phospholipase C production in Listeria monocytogenes: a convenient method to differentiate L. monocytogenes from other Listeria species.

The ability to produce phosphatidylcholine phospholipase C (lecithinase) is associated with virulence in pathogenic species of Listeria. Levels of production vary greatly among members of the genus, and this virulence factor is not readily detectable in many members of the pathogenic species on conventional agar media containing egg yolk, a common substrate for the enzyme. In this study, the influence of a variety of environmental parameters, including temperature, pH, and salt concentration, on the production of lecithinase by a number of strains was evaluated. Lecithinase production by Listeria monocytogenes LO28 in brain heart infusion medium was optimal at 1.75 to 2.0% NaCl; pH 7.0 to 7.3, and 37 to 40 degrees C, and the presence of oxygen had no effect. In a chemically defined medium, the optimal NaCl concentration and temperature were lower at 0.75 to 1.0% NaCl and 33.5 degrees C. As detection of virulence factors is useful to assist in the identification and differentiation of Listeria species, this report shows that lecithinase activity can conveniently be detected within 36 h on a relatively inexpensive medium. Under the conditions described, L. monocytogenes could be distinguished from other members of the genus as a result of distinct lecithin degradation which was not evident in L. innocua, L. seeligeri, L. ivanovii, L. welshimeri, or L. murrayi/grayi.

Culture Media, Serum-Free↗
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↗
PubMed1995

Dental anxiety and the absorption of orally administered erythromycin stearate.

Erythromycin stearate is an acid labile antibiotic, therefore fear and apprehension, which are known to affect gastric motility, may produce erratic absorption resulting in lower serum levels. The mean (SD) serum erythromycin concentration 75 minutes after a 1.5 gm oral dose of erythromycin stearate to 45 patients was 8.7 (4.8) mg/L and ranged widely from 0.4 to 20.5 mg/L. The serum concentration of erythromycin was below therapeutic levels (1.0 mg/L) in two patients. No significant association was found between anxiety and serum levels of erythromycin when age, gender, and gastric distress were taken into account. It is concluded that dental anxiety may indirectly influence the uptake of oral erythromycin stearate; but this relationship is complex, and there is no evidence from this study that increased dental anxiety decreases the uptake of the drug.

Adult↗
PubMed1995

A feasibility study on the use of direct light silver stain compared with dark field microscopy for differential counting of subgingival plaque.

The purpose of the present study was to compare direct light microscopy using a silver stain, with dark field microscopy for differential counting of subgingival plaque samples from patients with periodontitis. The feasibility of using the staining method was assessed on subgingival plaque samples which were collected at 34 sites from patients with untreated adult periodontitis. Differential counts of plaque morphotypes assessed by both methods showed close agreement. The proportions of spirochaetes assessed by both methods were significantly associated with probing depth. The silver stain proved a simple, rapid and inexpensive method for differential counting of plaque composition. This method is suitable for possible use in general dental practice where smears could be made at the chair-side and allowed to dry ready for staining and counting at the dentist's convenience using a simple light microscope. A permanent record is also produced which could allow for comparison of samples from before and after treatment and could be used as an aid to patient motivation in suitable cases.

Adult↗
PubMed1995

The use of tranexamic acid to reduce postoperative bleeding following cardiac surgery: a double-blind randomized trial.

Bleeding during the first 24 hours following cardiac surgery using cardio-pulmonary bypass (CPB) is a serious complication. Attempts to modify the degree of postoperative bleeding with pharmacologic therapy have met with limited success. Tranexamic acid, a potent inhibitor of plasminogen, may decrease the amount of mediastinal bleeding following surgery utilizing CPB. We assigned 30 patients who were about to undergo cardiac surgery to a double-blind randomized trial. The treatment group received tranexamic acid, given intravenously as 10 mg/kg over 30 minutes, at the time of skin incision, followed by a 1 mg/kg/hr infusion for 12 hours. The control group received a placebo (saline) of equal volume. Measurements of shed mediastinal blood and transfused homologous blood were made at 6, 12, and 24 hours postoperatively. Mediastinal blood loss in the treatment and control groups was 382 mL versus 594 mL at 6 hours (P = 0.08), 502 mL versus 848 mL at 12 hours (P = 0.04), and 711 mL versus 1160 mL at 24 hours (P = 0.02). The mean transfusion volumes after 24 hours were 356 mL in the treatment group and 528 mL in the placebo group (P = NS). Prophylactic tranexamic acid infusion decreases mediastinal blood loss following cardiopulmonary assisted cardiac surgery.

Blood Transfusion↗
PubMed1994

A 6.5-Mb yeast artificial chromosome contig incorporating 33 DNA markers on the human X chromosome at Xq22.

The Xq22 region of the human X chromosome contains genes for a number of inherited disorders. Sixty-nine yeast artificial chromosome clones have been isolated and assembled into a 6.5-Mb contig that contains 33 DNA markers localized to this region. This contig extends distally from DXS366 to beyond DXS87 and includes the genes involved in X-linked agammaglobulinemia (btk), Fabry disease (GLA), and Pelizaeus-Merzbacher disease (PLP). The order of markers in this contig is consistent with the known genetic and physical mapping information of Xq22. This cloned material provides a source from which to isolate other genes located in this part of the X chromosome.

Adult↗
PubMed1994

Nucleotide sequence and structural organization of the small, broad-host-range plasmid pCI411 from Leuconostoc lactis 533.

The nucleotide sequence of the Leuconostoc lactis 533 cryptic plasmid pCI411 (2926 bp) was determined. Analysis revealed the presence of three open reading frames (ORFs). ORF 1 was capable of encoding a 24.9 kDa peptide which shared homology with the replication initiation protein (RepB) from a number of Gram-positive rolling circle plasmids. ORF 2 could encode a peptide of 6.6 kDa which was homologous to the RepC protein of the lactococcal plasmid pWV01. A function could not be assigned to ORF 3, which was capable of encoding a 12.1 kDa peptide. Transcription-translation analysis indicated the presence of three peptides of the predicted molecular masses. A putative double strand origin of replication (DSO) was identified which showed strong similarity with the DSO of a number of Gram-positive plasmids including pE194 from Staphylococcus. Structural analysis identified a number of direct and indirect repeats in addition to putative recombination-specific sites (RSA and RSB) in the non-coding region of pCI411. The observed characteristics suggest that this plasmid replicates using the rolling circle mechanism. pCI411, which could be introduced into Leuconostoc, Lactococcus, Streptococcus, Lactobacillus and Bacillus is the first plasmid from the genus Leuconostoc to be characterized in such detail.

Amino Acid Sequence↗
PubMed1994

Effect of genetically modifying the lactococcal proteolytic system on ripening and flavor development in cheddar cheese.

THREE BATCHES OF SIX CHEDDAR CHEESES WERE MANUFACTURED BY USING THE FOLLOWING LACTOCOCCAL STRAINS: (i) UC317 as a control; (ii) JL3601, a proteinase-negative derivative of UC317 transformed with high-copy-number plasmid pCI3601 containing the cloned proteinase gene complex from UC317; (iii) AM312, a proteinase-negative derivative of UC317 transformed with plasmid pMG36enpr containing the neutral proteinase gene from Bacillus subtilis; (iv) AC322, JL3601 transformed with pMG36enpr; (v) AC311, UC317 transformed with plasmid pNZ1120, which contains the aminopeptidase N (pepN) gene from Lactococcus lactis subsp. lactis MG1363; and (vi) AC321, JL3601 transformed with pNZ1120. Organoleptic and chemical analyses indicated that (i) the control cheeses, which were made with UC317, were of the highest quality; (ii) cheeses made with strains harboring pCI3601 in addition to either pMG36enpr (AC322) or pNZ1120 (AC321) did not ripen in a significantly different manner than cheeses made with AM312 (containing only pMG36enpr) or AC311 (containing only pNZ1120), respectively; (iii) cheeses made with strains that overproduce pepN did not have improved body, texture, and flavor characteristics; and (iv) cheeses made with strains harboring the neutral proteinase from B. subtilis (AM312 and AC322) underwent greatly accelerated proteolysis.

Journal Article↗
PubMed1991

Role of cAMP-phosphodiesterase isozymes in pathogenesis of murine nephrogenic diabetes insipidus.

To test the hypothesis that rapid adenosine 3',5'-cyclic monophosphate (cAMP) catabolism via cyclic 3',5'-nucleotide phosphodiesterase (PDE) is a cause of the unresponsiveness to vasopressin (VP) in mice with hereditary nephrogenic diabetes insipidus (NDI), we investigated properties of PDEs and other aspects of the VP-dependent cAMP-signaling system in segments of collecting ducts [inner medullary (IMCD), cortical (CCD), and outer medullary (OMCD) ducts] microdissected from control mice and mice with NDI. The activity of cAMP-PDE, but not of cGMP-PDE, was markedly higher in IMCD (+109%), and to a lesser degree in OMCD (+41%) and CCD (+27%), of NDI mice than in normal controls. The cAMP-PDE in IMCD of NDI mice was more sensitive to inhibition by the PDE isozyme-specific inhibitors rolipram and cilostamide, but not by 3-isobutyl-1-methylxanthine, than was the cAMP-PDE in controls. Levels of cAMP in intact IMCD and CCD from NDI mice completely failed to increase in response to 10(-6) M VP. Incubation with rolipram alone, but not with cilostamide alone, restored VP-dependent cAMP accumulation in IMCD of NDI mice to the levels found in control mice; addition of cilostamide further enhanced the effect of rolipram. Analogous (but quantitatively lesser) anomalies of the VP-dependent cAMP system, including the effects of PDE inhibitors, were observed also in CCD of NDI mice. However, the activity of VP-stimulated adenylate cyclase assayed in permeabilized IMCD did not differ in NDI and control mice. These results indicate that anomalously high activities of low-Km cAMP-PDE isozymes account for the failure of collecting ducts of NDI mice to increase cAMP levels in response in VP.(ABSTRACT TRUNCATED AT 250 WORDS)

3',5'-Cyclic-AMP Phosphodiesterases↗
PubMed1990

Bacteremia in children following dental extraction.

The incidence and intensity of bacteremia following tooth extraction in children were measured by blood culture. The effects on bacteremia of the number and type of teeth extracted, oral hygiene, gingival health, presence of abscess, and antibiotic prophylaxis were assessed. Antibiotic prophylaxis reduced the incidence of bacteremia from 63% to 35%. The intensity of bacteremia was 2 cfu/mL of blood or less in 80% of the children. An agar pour-plate method of blood culture was significantly more effective than broth in culturing the small volumes of inoculum. Of 83 bacterial strains characterized, 39 were strict anaerobes or micro-aerophilic, and the remainder mainly streptococci. S. mitior and S. sanguis were most commonly isolated, often in pure culture, and were generally sensitive to antibiotics. No direct association was demonstrated between the plaque and gingival indices and incidence of bacteremia or between the number of teeth extracted and the incidence or intensity of bacteremia. It is concluded that all children at risk from infective endocarditis require antibiotic prophylaxis prior to tooth extraction, since it is impossible for the likelihood or intensity of transient bacteremia to be clinically predicted.

Adolescent↗
PubMed1989

Small intestinal submucosa as a large diameter vascular graft in the dog.

Autogenous saphenous vein and synthetic materials, such as Dacron and expanded polytetrafluoroethylene, have been used extensively as vascular grafts with moderate success. Improved success rates for vascular graft surgery may be possible if superior graft material was available. We tested the use of autogenous small intestinal submucosa (SIS) as a large diameter (10 mm) vascular graft in the infrarenal aorta of 12 dogs. One dog died with graft thrombosis within 48 hr of surgery. Nine dogs were sacrificed at various times during a 52-week post-surgical period and showed patent grafts without infection, thrombosis, intimal hyperplasia, or adverse effects upon blood pressure. There was no ultrastructural evidence of endothelial cell growth on the luminal surface of the SIS graft which was composed of a dense, non-thrombogenic, organized collagenous connective tissue. The SIS material was approximately one order of magnitude less elastic than natural aorta and showed an immediate dilatation of approximately 18% after exposure to the systemic blood pressure. However, there was no progressive dilatation during the 52-week postsurgical period. Two dogs remain alive at 8 and 52 weeks post-surgery with patent grafts as determined by positive contrast radiography and Doppler studies. We conclude that autogenous small intestinal submucosa can be successfully used as a large diameter arterial graft in the dog and is worthy of further investigation.

Animals↗
PubMed1986

Capsulation of in vitro and in vivo grown Bacteroides species.

By centrifugation on a four step Percoll density gradient cells of Bacteroides species could be separated according to the size of extracellular structure. The difference in size was visible by both light and electron microscopy. Two structures were observed on Bacteroides fragilis by electron microscopy, namely a fibrous network and an electron dense layer. An electron dense layer was visible on Bacteroides ovatus only when stained with ruthenium red. B. fragilis cells grown in the mouse peritoneal cavity did not produce a large fibrous network. An electron dense layer was observed on some cells in the presence of ruthenium red stain and cells possessing this layer were phagocytosed in vivo.

Animals↗
PubMedDate not supplied

Advanced dietetic training in nutrition support and metabolism: the University of Pennsylvania Medical Center experience.

The dietetic fellowship at the University of Pennsylvania Medical Center is highly rewarding for the nutrition support dietitians, and the dietetic fellows have identified an increased self-confidence as one of the major benefits. Advanced training of this nature is very labor intensive. In the current environment of cost containment and down-sizing of staff, it is unlikely that this type of program will flourish due to the high labor cost involved and limited funding available.

Academic Medical Centers↗
PubMedDate not supplied

A new candidate region for the positional cloning of the XLP gene.

X-linked lymphoproliferative disease (XLP) is an inherited immunodeficiency characterised by selective susceptibility to Epstein-Barr virus and frequent association with malignant lymphomas chiefly located in the ileocecal region, liver, kidney and CNS. Taking advantage of a large bacterial clone contig, we obtained a genomic sequence of 197620 bp encompassing a deletion (XLP-D) of 116 kb in an XLP family, whose breakpoints were identified. The study of potential exons from this region in 40 unrelated XLP patients did not reveal any mutation. To define the critical region for XLP and investigate the role of the XLP-D deletion, detailed haplotypes in a region of approximately 20 cM were reconstructed in a total of 87 individuals from 7 families with recurrence of XLP. Two recombination events in a North American family and a new microdeletion (XLP-G) in an Italian family indicate that the XLP gene maps in the interval between DXS1001 and DXS8057, approximately 800 kb centromeric to the previously reported familial microdeletion XLP-D.

Base Sequence↗