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Biomedical subjects

J Flynn

Publications and source records attributed to J Flynn.

At least 55 records · Page 3Linked to original sources
PubMed1996

The dynamics of microbial colonization of barrier membranes for guided tissue regeneration.

The microbial colonization of expanded polytetrafluoroethylene membrane by putative periodontopathogens at 3 minutes of intraoral manipulation was determined in 42 patients with 42 mandibular posterior two- to three-wall defects. Twenty patients exhibited no periodontal pockets of > or = 5 mm, other than the study site, and low levels of pathogens (group A). Twenty-two patients revealed multiple periodontal pockets of 5 mm or more and numerous pathogens (group B). Within the preceding 3 months of regenerative surgery, group A patients had received apically positioned flap surgery with osseous recontouring (except for the study site), and group B patients had been enrolled in a non-surgical maintenance program. The subgingival microbiota was examined prior to regenerative therapy, and the membrane microbiota was examined at 3 minutes and at the time of removal at 6 weeks by culture, DNA probes, and phase-contrast microscopy. The mean initial defect depth was 7.4 mm for group A and 7.2 mm for group B. At 6 months, the difference in mean clinical attachment gain was statistically significant (P < 0.001; group A: 3.4 mm; group B: 1.4 mm). At 3 minutes, putative pathogens were detected in seven (16.7%) membranes in group B (group Binfected), and the associated sites gained only 0.6 mm in clinical attachment at 6 months. Clinical attachment gain was modeled as a linear function of the explanatory variables (r2 = 86%). The presence of Porphyromonas gingivalis detected by DNA probe at 3 minutes was associated with 1.5 mm less expected gain (P = 0.0002). Total microbial counts and the percentage of Peptostreptococcus micros and Capnocytophaga species at baseline, and of motile rods on the membrane surface facing the gingiva at 6 weeks, were statistically significant negative predictors of clinical attachment. For each week the membrane remained covered, an additional 0.5 mm gain could be expected (P = 0.002); and for every 10 sites that exhibited bleeding on probing, the clinical attachment gain was 0.6 mm less at the site of regeneration (P < 0.0001). The present results showed that putative pathogens may colonize membranes within 3 minutes of intraoral manipulation. The patient group treated with periodontal osseous surgery revealed the lowest levels of periodontal pathogens in the membranes and exhibited the most gain in clinical attachment.

Adult↗
PubMed1995

Purification and stabilization of mouse DNA methyltransferase.

Cytosine methylation within DNA has been implicated in genetic imprinting, X-chromosome inactivation, regulation of tissue-specific gene expression, aging, and cancer. Unfortunately, DNA (cytosine-5)-methyltransferases (EC 2.1.1.37) from various mammalian sources have been difficult to isolate and stabilize, precluding investigations of these critical enzymes. We describe a novel FPLC purification of the 190,000 Mr DNA methyltransferase from mouse Friend erythroleukemia cells. The homogeneous 190 kD Mr form of the enzyme is the only polypeptide detected at various stages of cell growth and has not undergone detectable N-terminal proteolysis.

Amino Acid Sequence↗
PubMed1995

Evaluation of a PCR based method for identification of mycobacterial isolates.

In recent years an increasing number of mycobacterial species have been described as causing disease in humans. Identification of isolates to the species level is essential for evaluation of the significance of an isolate. Conventional methods for identification based on selective inhibitors of growth and biochemical reactions are slow. We have evaluated a novel method, PCR restriction enzyme pattern analysis (PRA), for identification of mycobacterial isolates. Fifty three cultures including a mixed culture of M. tuberculosis and M. avium and four mycobacterial cultures contaminated with rapidly growing organisms of other genera were studied. The method permits identification of most isolates within 1 to 2 days, including some contaminated cultures, and results were generally in accordance with those obtained by conventional methods.

Bacteriological Techniques↗
PubMed1995

Evaluation of a PCR assay for detection of Mycobacterium tuberculosis in clinical specimens.

A polymerase chain reaction (PCR) assay for detection of M. tuberculosis was optimized for application to clinical specimens, which were prepared for amplification by boiling in buffer. The buffer contained a synthetic DNA fragment to determine if DNA amplification from the individual prepared specimens was subject to inhibition because of substances present in the specimen, or by the process of specimen preparation or storage. The PCR test was less sensitive than direct microscopy (75% as against 87.5%) and had a specificity of 97%. Invalid results due to inhibition of amplification occurred in 12% of specimens. Incorporation of the internal standard into the specimen preparation buffer ensures that any step in the process which inhibits DNA amplification is detected in the failure of amplification of the internal standard. The use of internal standard in this way should be considered in developing diagnostic protocols.

Base Sequence↗
PubMed1995

Major influences on maternal responsiveness to infants.

Thirty healthy, middle-class mothers were interviewed during their postpartum hospital stay to identify major influences on mothers' responses to their infants. Sullivan's theorem of tenderness served as a guide for exploring maternal responsiveness. Three major categories, infant tenderness needs, maternal perception, and maternal needs, and their related properties, were described. Support persons were viewed as very important. Mothers also believed that some infant needs were more important than others. Finally, mothers felt that they were constantly faced with priorities, and that the emotional state of the mother and infant often influenced their interaction.

Adult↗
PubMed1995

Effects of nitric oxide synthase inhibitors on murine infection with Mycobacterium tuberculosis.

We have recently demonstrated that the macrophage L-arginine-dependent cytotoxic pathway effectively kills the virulent Erdman strain of Mycobacterium tuberculosis in vitro via the generation of toxic reactive nitrogen intermediates by the enzyme nitric oxide synthase. This report demonstrates that two distinct inhibitors of nitric oxide synthase (aminoguanidine and NG-monomethyl-L-arginine) render similar deleterious effects on tuberculous infection in mice, as assessed by mortality, bacterial burden, and pathological tissue damage, thus confirming the importance of reactive nitrogen intermediates in resistance against M. tuberculosis.

Amino Acid Oxidoreductases↗
PubMed1995

Multiplex PCR for identifying mycobacterial isolates.

AIMS: To develop a multiplex polymerase chain reaction (PCR) method to facilitate identification of mycobacterial isolates. METHODS: Type strains of 14 species of mycobacteria and 56 clinical isolates were lysed by boiling in TE Triton. The lysate (5 microliters) was used directly in a PCR reaction incorporating three pairs of PCR primers expected to amplify fragments from the genome of (a) all mycobacteria, (b) Mycobacterium tuberculosis complex only and (c) M avium only. PCR products were visualised by electrophoresis on agarose gels. RESULTS: Multiplex PCR applied to 14 type strains yielded patterns on electrophoresis which permitted identification of the mycobacterial isolates as M tuberculosis complex, M avium or as mycobacteria other than the former. The identification of 56 clinical isolates by multiplex PCR was consistent with other methods and was accomplished in less than one working day. CONCLUSIONS: This method may facilitate rapid and convenient identification of most clinical isolates of mycobacteria by PCR and gel electrophoresis. Further evaluation is warranted.

Base Sequence↗
PubMed1994

PCR based fingerprinting of Enterobacter cloacae.

An outbreak of lower respiratory tract infection with Enterobacter cloacae occurred in an intensive care unit in a university teaching hospital. Random amplification of polymorphic DNA (RAPD) was used to assist in the investigation of the outbreak. The technique was readily applied to this organism and permitted differentiation between strains which had identical biochemical profiles and antibiograms. The versatility of this technique makes it attractive for use in hospitals where fingerprinting of any one of the many Gram-negative rods associated with nosocomial infection may be required from time to time.

Cross Infection↗
PubMed1994

Experimental approaches to mechanisms of protection and pathogenesis in M. tuberculosis infection.

It has, for many years, been widely assumed that the fundamental mechanism of protection in tuberculosis infection is a CD4 T cell response producing lymphokines that activate macrophages to kill or restrict the intracellular growth of M. tuberculosis. Just as certain cytokines, e.g. IFN-gamma, are currently perceived to be important for protection, others, particularly tumor necrosis factor (TNF), are thought to be responsible for much of the tissue destruction associated with the disease. Yet there are remarkably few critical experimental or clinical data that have defined the immunological requirements for protection and pathogenesis. One of the initial stimuli to the work we have undertaken has been careful reflection on the results of the many prospective trials of BCG against tuberculosis. Two aspects have impelled us to reconsider conventional wisdom. The first, of course, is the wide discrepancy in the degree of protection imparted, ranging from 0% in South India to 77% in the British MRC trial (1, 2). The second is that, in all trials that examined them, skin test conversions to tuberculin positivity were 85% or greater, indicating a disparity between the presence of delayed hypersensitivity to tuberculin and protection. We and others have argued (1, 2) that there are multiple possible explanations for this discrepancy, the principal one being protection caused by infection with environmental mycobacteria. But, the general point raised is whether cell mediated immunity as manifested by CD4+ cell production of lymphokines and macrophage activation is a sufficient mechanism for protection against M. tuberculosis infection.

Animals↗
PubMed1994

A complex bilateral polysyndactyly disease locus maps to chromosome 7q36.

We demonstrated that the gene responsible for a congenital limb deformity (polysyndactyly) maps to chromosome 7q36 in a large family. Pre- and postaxial anomalies of the extremities are inherited in this family as an autosomal dominant trait. The disease locus is closely linked to D7S550 (maximum lod score = 6.85, theta = 0). This region is homologous to a segment of mouse chromosome 5, where the mutations hammer toe (HM) and hemimelic extra toes (HX) have been mapped. These data suggest that human chromosome 7q36 and the homologous region of mouse chromosome 5 contain genes involved in limb pattern formation.

Base Sequence↗
PubMed1994

Left ventricular dysfunction and acute lung injury induced by continuous administration of endotoxin in sheep.

Sixteen sheep were surgically prepared for chronic study. Seven days later, Escherichia coli endotoxin (10 ng/kg/min, lipopolysaccharide (LPS) group, n = 10) or an equivalent amount of 0.9% NaCl (Control group n = 6) was administered. Between 1 and 8 h post-LPS, there was a hypodynamic state with low cardiac index (CI, LPS 5.0 +/- 0.2; sham 6.3 +/- 0.4 liters/min/m2 at 4 h). During this period, the left ventricular end-systolic pressure-diameter relationship (ESPDR), a sensitive index of myocardial contractility, was also lower (LPS 10.4 +/- 1.2; sham 17.2 +/- 0.8 mmHg/mm). Mean pulmonary arterial pressure (PAP) and pulmonary vascular resistance index (PVRI) were remarkably increased 1 h after the administration of LPS (PAP:LPS 37.5 +/- 1.9; sham 21.8 +/- 0.9 mmHg, PVRI: LPS 600 +/- 58; sham 158 +/- 23 dynes x s x cm-5 x m2). The early changes in cardiopulmonary function occurred concomitantly with an elevation in tumor necrosis factor (LPS 1221 +/- 520; sham 0 +/- 0 pg/ml) and thromboxane B2 (LPS 1382 +/- 266; baseline 82 +/- 20 pg/ml) in arterial blood. Following this first phase, the sheep presented a persistent hyperdynamic state characterized by a significant increase in CI. The ESPDR continued to fall. By 24 h post-LPS the CI was 10.1 +/- 0.5 liters/min/m2 (sham, 6.3 +/- 0.3) but the ESPDR had fallen to 8.2 +/- 2.3 mmHg/mm (sham 16.0 +/- 3.0). The pulmonary hypertension was maintained for the duration of the LPS infusion.(ABSTRACT TRUNCATED AT 250 WORDS)

Acute Disease↗
PubMed1994

Molecular detection of Bacteroides forsythus in human periodontitis.

The usefulness of a digoxigenin-labeled genomic DNA probe for the detection of subgingival Bacteroides forsythus was examined. In addition, the arbitrarily primed polymerase chain reaction (AP-PCR) was used to delineate the genetic diversity of B. forsythus periodontal isolates. The DNA probe detected 10(3) B. forsythus cells and yielded a strong signal at 10(4) cells. It reacted with B. forsythus ATCC 43037T and 44 clinical isolates and showed no detectable reactivity with 75 strains of 24 other oral microbial species. In comparison to culture, the DNA probe in a dot-blot method demonstrated a sensitivity of 88.8% and a specificity of 38.4% (accuracy, 72.5%). By colony-blotting on primary plates, a sensitivity of 98.1% and a specificity of 53.8% (accuracy, 82.5%) were obtained. B. forsythus was detected in 449 (73.1%) of 614 periodontitis patients. The occurrence of the organism was closely associated with Porphyromonas gingivalis, both species being present in 54.8% and absent in 22.2% of 270 study samples. AP-PCR identified 24 B. forsythus genotypes among 27 test strains. This study demonstrated the utility of a non-radioactive genomic probe for direct detection of B. forsythus in subgingival specimens. The species showed a considerable degree of genetic diversity. DNA analysis may help to determine the role of B. forsythus in periodontal disease and its mode of transmission among exposed individuals.

Adolescent↗
PubMed1994

Gender, race, and perception of environmental health risks.

This paper reports the results of a national survey in which perceptions of environmental health risks were measured for 1275 white and 214 nonwhite persons. The results showed that white women perceived risks to be much higher than did white men, a result that is consistent with previous studies. However, this gender difference was not true of nonwhite women and men, whose perceptions of risk were quite similar. Most striking was the finding that white males tended to differ from everyone else in their attitudes and perceptions--on average, they perceived risks as much smaller and much more acceptable than did other people. These results suggest that socio-political factors such as power, status, alienation, and trust are strong determiners of people's perception and acceptance of risks.

Data Collection↗
PubMed1993

A comparison of antimicrobial sensitivities of urinary pathogens for the years 1980 and 1990.

Urinary tract infection is a major cause of morbidity in both the hospital and community which often requires empirical therapy. We have retrospectively studied laboratory diagnosed urinary tract infections for the years 1980 and 1990 to document the common pathogens and antimicrobial susceptibility patterns. In 1990 a significantly lower proportion of specimens yielded Proteus sp. or Klebsiella sp. than was the case in 1980. This was true of specimens from both the hospital and the community. There was an increase in the proportion of specimens yielding Pseudomonas sp. and coagulase negative Staphylococci (CNS). Significant changes in the antimicrobial susceptibility of urinary pathogens are also noted. In particular a greater proportion of isolates from the community were sensitive to cephalothin in 1990, while fewer isolates were sensitive to nalidixic acid and gentamicin. A greater proportion of isolated from hospital practice were sensitive to ampicillin, to cephalothin and to trimethoprim in 1990 while fewer isolates were sensitive to gentamicin. In relation to nitrofurantoin no significant change was noted. In respect of isolates from both community and hospital practice the agents ofloxacin, co-amoxiclav (not available in 1980) and gentamicin are those which are most consistently active.

Anti-Bacterial Agents↗
PubMed1992

Tuberculosis in the west of Ireland 1986-1990.

A review of mycobacteria isolated from clinical samples from the Western Health Board Area (WHBA) for the years 1986 to 1990 was performed to establish the pattern of mycobacterial infection. The incidence of microbiologically proven cases of tuberculosis (13.3/100,000) and of sputum smear positive cases (6.2/100,000) was determined and correlated with notification data. M. bovis accounts for 6.3% of cases of microbiologically confirmed tuberculosis in this area. Resistance to one or more of the first line anti-tuberculous drugs was noted in 5.3% of isolates (excluding pyrazinamide resistance in M. bovis). Clinically significant isolates of mycobacteria other than tuberculosis (MOTT) were rare throughout the five year period. The overall incidence of microbiologically proven cases of tuberculosis is relatively high and M. bovis and drug resistant isolates of M. tuberculosis are relatively common.

Drug Resistance, Microbial↗