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Biomedical subjects

A Murray

Publications and source records attributed to A Murray.

At least 343 records · Page 19Linked to original sources
PubMed1986

Antigenic specificity of human antibody to chlamydia in trachoma and lymphogranuloma venereum.

An understanding of the molecular basis of the humoral immune response to chlamydial infections in man requires the identification of target antigens to which antibodies are directed. The antigenic specificity of antibody from patients with lymphogranuloma venereum (LGV) or trachoma was therefore assessed by Western blotting. Surface polypeptides were first identified using purified chlamydial outer membrane complex as antigen. Antibodies in sera from patients with LGV but not from control negative sera reacted with a wide range of chlamydial surface polypeptides with molecular masses of 19, 29, 41, 58, 63 and 65 kDa. The major component of the antibody response detected by both immunoblotting and immunoprecipitation assay was directed against the major outer membrane protein (MOMP). Antibody to MOMP was species-specific on Western blotting, whereas antibody to several other polypeptides recognized common immunodeterminants on polypeptides of C. psittaci Cal-10 of equivalent molecular mass. Immunologically C. psittaci Cal-10 was more closely related to LGV strains of C. trachomatis than a guinea pig inclusion conjunctivitis strain of C. psittaci. Trachoma sera collected from a village in southern Iran showed predominantly type-specific antibody on micro-immunofluorescence to serotype A or B trachoma agents. These sera showed a weak immune response to MOMP, a pronounced response to a polypeptide of 36 kDa and much less widespread reactivity with other chlamydial polypeptides. The lack of an immune response to SDS-stable immunodeterminants on MOMP might contribute to the susceptibility of trachoma patients to repeated cycles of ocular infection with chlamydiae.

Antibodies↗
PubMed1986

Monitoring EEG frequency and amplitude during cardiac surgery.

Changes in the electroencephalograms of patients undergoing cardiac surgery with cardiopulmonary bypass were studied. An analysis technique with a simple display of amplitude and frequency within the traditional bands was used. During the course of an operation, there can be dramatic changes in frequency contribution with little or no change in overall EEG amplitude. Evaluation of the results shows that this technique clearly draws attention to periods of EEG change, and examples are given.

Cardiac Surgical Procedures↗
PubMed1985

Comparison of EEG monitoring techniques: an evaluation during cardiac surgery.

A single channel EEG recording was made in 25 patients undergoing cardiac surgery and analysed using 5 different techniques--amplitude, cerebral function monitor, Fourier, Hjorth, and zero-crossing analyses. The results of the analyses were plotted as trend information on paper. These trends were studied for changes in the EEG during surgery. In the majority of cases changes were noted simultaneously by all 5 techniques. There were, however, some cases in which an amplitude-only technique showed no changes while frequency contributions were changing, and a frequency-only technique showed no changes while amplitudes were changing. The conclusion drawn is that major EEG changes are observed with any of the techniques studied, but that for improved sensitivity a technique analysing both frequency and amplitude information should be used.

Brain↗
PubMed1985

Potential use of ultrasound in place of X-ray fluoroscopy in urodynamics.

A moving picture can be obtained using an ultrasonic scanning probe in the rectum to provide information about the bladder and urethra in the same projection as for lateral cystography. The method has potential as a substitute for cinecystography but there are a number of problems still to be overcome.

Cough↗
PubMed1984

Automatic analysis of ambulatory ECG records.

Fully automatic or semi-automatic analysis of ambulatory ECG records is a method of dealing with the enormous processing problems posed by 24 h surface ECG recording. Successful automation of 'book-keeping' and event detection has been realized, but automation of event diagnosis and presentation of the final report remains problematic. To date, the reliable detection of ventricular ectopic complexes has received much emphasis, but many other features which may reflect the arrhythmia substrate are not routinely analysed. Future developments may require consideration of this area. Regardless of the recording and analysis system, and regardless of the application, human involvement with data interpretation remains indispensable.

Ambulatory Care↗
PubMed1984

Delayed ventricular depolarization--correlation with ventricular activation and relevance to ventricular fibrillation in acute myocardial infarction.

Signal averaging to detect abnormalities in the terminal phase of ventricular depolarization has been performed in several groups of patients with various manifestations of ischaemic heart disease. Late potentials were common in patients with VT and in a group of patients having cardiac surgery. Findings in the surgical group highlighted the close correlation of late potentials with delayed, fragmented epicardial activation supporting the hypothesis that late potentials reflect a myocardial substrate which would support re-entrant VT. The findings in the surgical group allowed a definition of late potentials which could be applied to other patients in the study, and also demonstrated a spectrum of late depolarization abnormalities. Signal averaging is technically feasible in the noisy CCU environment but late potentials were detected in few patients early in AMI. Late potentials were also rarely seen in patients with VF and therefore cannot be construed as a predictive index of this arrhythmia.

Adult↗
PubMed1984

Control mechanisms governing the infectivity of Chlamydia trachomatis for HeLa cells: the role of calmodulin.

Adhesion of the obligate intracellular bacterium Chlamydia trachomatis to host cells is associated with a flux of Ca2+ across the cell membrane, and infection is enhanced by treatment of host cells with Ca2+ ionophore. The possibility that Ca2+ might interact with host cell Ca2+ regulatory proteins to promote chlamydial infection was investigated. Treatment of HeLa 229 cells with the calmodulin inhibitors pimozide, trifluoperazine, chlorpromazine, promethazine or haloperidol reduced chlamydial infectivity as measured by inclusion counting or the specific incorporation of [3H]threonine. The inhibitory effect was reversible, dose-related and shown to be associated with impairment of chlamydial adhesion and uptake by the host cells. This effect was clearly distinguished from the delayed maturation of chlamydiae due to continuous exposure to calmodulin inhibitors which may result from a decrease in the availability of high energy compounds from the host cells necessary for chlamydial growth. The possible mechanisms for calmodulin-mediated chlamydial endocytosis are discussed.

Adhesiveness↗
PubMed1984

Control mechanisms governing the infectivity of Chlamydia trachomatis for HeLa cells: mechanisms of endocytosis.

The mechanism by which Chlamydia trachomatis is endocytosed by host cells is unclear. Studies of the kinetics of chlamydial attachment and uptake in the susceptible HeLa 229 cell line showed that chlamydial endocytosis was rapid and saturable but limited by the slow rate of chlamydial attachment. To overcome this limitation and to investigate the mechanism of endocytosis, chlamydiae were centrifuged onto the host cell surface in the cold to promote attachment. Endocytosis of the adherent chlamydiae was initiated synchronously by rapid warming to 36 degrees C. Electron micrographs of chlamydial uptake 5 min after onset showed that chlamydial ingestion involves movement of the host cell membrane, leading to interiorization in tight, endocytic vacuoles which were not clathrin coated. Chlamydial ingestion was not inhibited by monodansylcadaverine or amantadine, inhibitors of receptor-mediated endocytosis and chlamydiae failed to displace [3H]sucrose from micropinocytic vesicles. Chlamydial endocytosis was markedly inhibited by cytochalasin D, an inhibitor of host cell microfilament function, and by vincristine or vinblastine, inhibitors of host cell microtubules. Hyperimmune rabbit antibody prevented the ingestion of adherent chlamydiae, suggesting that endocytosis requires the circumferential binding of chlamydial and host cell surface ligands. These findings were incompatible with the suggestion that chlamydiae enter cells by taking advantage of the classic mechanism of receptor-mediated endocytosis into clathrin-coated vesicles, used by the host cell for the internalization of beta-lipoprotein and other macromolecules, but were consistent with the hypothesis that chlamydiae enter cells by a microfilament-dependent zipper mechanism.

Cadaverine↗
PubMed1983

Incidence and prognostic importance of jaundice after cardiopulmonary bypass surgery.

In a prospective study of 248 consecutive patients undergoing cardiopulmonary bypass surgery, early postoperative "post-pump" jaundice (PPJ) developed in 49 (20%). Development of PPJ was strongly associated with a bad outcome; 25% of jaundiced patients and 1% of non-jaundiced patients died in the postoperative period. The jaundice was a conjugated hyperbilirubinaemia, and was detectable in 48 out of 49 patients by postoperative day 2. Hypotension, hypoxia, and hypothermia ("shocked liver") were not associated with the development of PPJ, nor was evidence of haemolysis or heart-failure. Although PPJ was significantly associated with multiple valve replacement, higher transfusion requirements, and longer cardiopulmonary bypass time, it also occurred in patients undergoing uncomplicated operations. It is suggested that PPJ is caused by a defect in hepatic excretion of bilirubin.

Bilirubin↗
PubMed1983

Comparative study of the sodium salts of iodamide and iothalamate in clinical urography.

In a comparative urographic study of the sodium salts of iodamide (Uromiro 300 Sodium) and iothalamate (Conray 420) the following conclusions have been made. (i) In subjects with radiologically normal kidneys and a creatinine clearance greater than 70 ml/min, nephrogram scores were significantly higher with iodamide (P less than 0.02). There were differences between the media in respect of total urogram scores and pyelogram scores but they were not statistically significant. (ii) In patients with radiologically normal kidneys and a spectrum of normal and abnormal renal function, performance scores for iothalamate showed no significant relationship with creatinine clearance. Results for iodamide, however, showed some relationship with creatinine clearance (nephrogram score r = 0.46, pyelogram score r = 0.38, total urogram score r = 0.49). A possible mechanism for this is proposed. (iii) Side-effects encountered in the study were mild and there were no significant differences between the contrast media in either the incidence or severity of the side-effects. (iv) Blood-pressure and pulse-rate profiles following iodamide were not significantly different from those following iothalamate. (v) Cardiac arrhythmias were mild and uncommon.

Adult↗