Search PubMed⌕ Search

Biomedical subjects

M Matheson

Publications and source records attributed to M Matheson.

27 records · Page 2Linked to original sources
PubMed1993

Isolation of a putative fimbrial adhesin from Bordetella pertussis and the identification of its gene.

We report the purification of a minor Bordetella pertussis fimbrial subunit, designated FimD, and the identification of its gene (fimD). FimD could be purified from the bulk of major fimbrial subunits by exploiting the fact that major subunit-subunit interactions are more stable in the presence of SDS than minor-major subunit interactions. To locate the gene for FimD, internal peptides of FimD were generated, purified and sequenced. Subsequently, an oligonucleotide probe, based on the primary sequence of one peptide, was used to clone fimD. The primary structure of FimD, derived from the DNA sequence of its gene, showed homology with a number of fimbrial adhesins. Most pronounced homology was observed with MrkD, a fimbrial adhesin derived from Klebsiella pneumoniae. These observations suggest that FimD may represent a B. pertussis fimbrial adhesin. With a fimD-specific probe we detected the presence of a fimD homologue in Bordetella parapertussis and Bordetella bronchiseptica but not in Bordetella avium. Cloning and sequencing revealed that the B. parapertussis and B. bronchiseptica fimD product differed from the B. pertussis fimD product in 20 and 1 amino acid residues, respectively. Since B. bronchiseptica is normally not a human pathogen, but causes respiratory disease in a wide range of non-human mammalian species, this may suggest that FimD recognizes a receptor that is well conserved in mammalian species. An in-frame deletion in fimD completely abolished FimD expression and also affected the expression of the major subunits Fim2 and Fim3 suggesting that, in contrast to other adhesins that are minor components of fimbriae, FimD is required for formation of the fimbrial structure.

Amino Acid Sequence↗
PubMed1981

Coexistence of sick sinus rhythm and atrial flutter-fibrillation.

A 58-year-old man with hypertensive cardiovascular disease and atrial flutter underwent electrophysiologic studies, including multiple intra-atrial recordings and atrial stimulation. Although the surface ECG suggested the presence of atrial flutter, intra-atrial recordings demonstrated the presence of (1) sinus-like rhythm localized to an area of approximately 5 mm in and around the region of the sinus node, which was protected by entrance block; (2) flutter and/or fibrillation of the remaining parts of the right atrium; (3) fibrillation of the left atrium; and (4) transient degeneration of flutter into fibrillation at right atrial sites, with predominant flutter activity. Although a major part of the right atrium was in flutter and/or fibrillation, we could assess sinus node function by overdrive stimulation of the area of sinus node-activity. Sinus node function studied revealed an underlying sick sinus syndrome.

Atrial Fibrillation↗
PubMed1980

Computed tomography of fetal specimens.

Computed tomography has been used to provide cross-sectional images of fetal specimens. This technique allows us to gain information on anatomic malformations and in general is a useful tool for research and teaching.

Abortion, Therapeutic↗
PubMed1980

Prediction of late ischemic complications after cerebral aneurysm surgery by the intraoperative measurement of cerebral blood flow.

The response of cerebral blood flow (CBF) to drug-induced hypotension was measured in 20 patients who underwent craniotomy for clipping of a cerebral aneurysm following subarachnoid hemorrhage. A modified intravenous xenon-133 injection technique was used to monitor CBF. In 15 patients, CBF increased significantly with hypotension, and only one developed a late neurological deficit. In five patients, CBF fell with halothane-induced hypotension, and four developed delayed neurological deficits. Measurement of the intraoperative CBF response to halothane-induced hypotension may reveal those patients at greatest risk of developing late neurological deficits and who require more intensive postoperative monitoring and early use of the induced hypertension technique.

Blood Pressure↗
PubMed1979

Accuracy of ventricular volume estimation.

Sources of error in the estimation of ventricular volume from CAT scans are discussed and the accuracy of the measurement assessed. Two methods of calculating ventricular volume from an intraventricular injection of radioisotope are described and compared. Finally, the CAT scan and isotope methods are compared and contrasted. The error associated with a single measurement of volume by any of these techniques is between 20% and 30%. In patients with no ventricular catheter there is no choice other than to use CAT scanning, but if intraventricular injection is possible this method offers a potentially more accurate volume determination because of his higher signal-to-noise ratio.

Cerebral Ventricles↗
PubMed1976

Three cases of granulomatous arachnoiditis after myelography.

Arachnoiditis occurring after myelography is well recognized and the mechanism is understood. Three cases of arachnoiditis caused by oily myelographic contrast media are presented. This complication of myelography may occur even if recognized precautions are observed. The general problem of encystment of dye with a chronic inflammatory process, fibrosis and granuloma formation is described.

Adult↗
PubMedDate not supplied

Asthma management: how effective is it in the community?

BACKGROUND: The National Asthma Campaign (NAC) was launched in Australia in 1989 with the major objective of improving asthma management through the implementation of a six-step asthma management plan. AIM: The objective of the present study was to analyse the management of asthma in a cohort of adults with self-reported asthma 10 years after the commencement of the NAC. METHODS: The subjects were participants in the laboratory phase of a cross-sectional epidemiological study conducted in Melbourne in 1999-2000. Participants completed the detailed European Community Respiratory Health Survey, which included specific questions about their asthma management. Participants were included in this analysis if they had a positive response to the question 'Have you ever had asthma?'. This resulted in a total of 435 subjects. RESULTS: Of the subjects with self-reported asthma, over half of the participants reported that a doctor had ever measured their breathing (52.9%). However, only 10.1% of participants reported that they owned a peakflow meter (PFM) and only 13.3% reported that they had ever been given a written action plan. In comparison with data reported from 1993, doctor measurement of lung function has decreased significantly (P < 0.000 1), as has PFM ownership (P < 0.0001) and, importantly, possession of a written action plan (P = 0.0004). CONCLUSIONS: Asthma management among adults still falls well short of NAC guidelines. The decline in some key features over recent years suggests that new management and dissemination strategies are required.

Adult↗
PubMedDate not supplied

Group B streptococcus (GBS) colonisation among expectant Irish mothers.

Group B streptococci (GBS) have been recognised for more than three decades as a serious cause of perinatal morbidity and neonatal mortality. The aim of this study was to accurately determine the prevalence of GBS carriage and the serotype distribution among pregnant Irish women. 504 women attending antenatal clinics had two swabs (one perianal and one low vaginal) taken in the last four weeks of their pregnancy. These were placed in Todd Hewitt broth and then subcultured onto solid media. Serotyping of the isolates was performed by the Central Public Health Laboratory, London. GBS colonised women were treated with prophylactic antibiotics in labour and their infants received prophylaxis for 48 hours. 129 women (25.6%) were found to be asymptomatically colonised with GBS. Dual site screening (low-vaginal and perianal) identified 5% more GBS carriers than one site would have done. Serotypes identified included types I (30%), II (17%), III (30%), IV (1%) and V (9%). GBS colonisation is very common in Irish pregnant women and therefore a strategy for management in pregnancy ought to be developed in order to reduce the recognised occurrence of neonatal morbidity and mortality caused by this organism.

Adolescent↗