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Biomedical subjects

J Ferguson

Publications and source records attributed to J Ferguson.

At least 127 records · Page 7Linked to original sources
PubMed1998

Respiratory infections in the community. A concise update.

BACKGROUND: The decision to institute antibiotic therapy is often empirical and based on historical precedent. As respiratory tract infections are the commonest reason for prescribing antibiotics and bacterial resistance to many drugs is increasing, it is important to look at the evidence for using antibiotics. OBJECTIVE: This article reviews the various components of the respiratory tree addressing the indications for instituting antibiotic therapy and the most appropriate antibiotic. DISCUSSION: The information contained in this article is based on the 10th edition of the Therapeutic Guidelines: Antibiotics. It is acknowledged that the decision of when and which antibiotics to prescribe must be made on an individual basis, however, by considering the broader ramifications of antibiotic use and the evidence of outcome studies, the decision can be based on a more rational approach.

Adult↗
PubMed1997

Risk stratification after myocardial infarction using signal-averaged electrocardiographic criteria adjusted for sex, age, and myocardial infarction location.

BACKGROUND: The objectives were to investigate the factors influencing signal-averaged ECGs (SAECGs) recorded in patients after myocardial infarction (MI) and to develop criteria for predicting arrhythmic events (AEs) that account for these factors. METHODS AND RESULTS: SAECGs were recorded 5 to 15 days after MI in 2461 patients without bundle-branch block. The duration (QRSd), terminal potential (VRMS), and terminal duration (LAS) of the filtered QRS were measured. During follow-up (17 +/- 8 months), AEs (arrhythmic death; ventricular tachycardia, VT; ventricular fibrillation, VF) occurred in 80 patients (3.3%). Receiver operating characteristic curves showed that QRSd discriminated patients with all types of AEs, but VRMS and LAS discriminated only VT patients; QRSd minus LAS also discriminated AE patients. Sex, age, and MI location significantly affected the SAECG; survivors without VT or VF were divided into subgroups (2 sex x 4 age x 2 MI), and QRSd values exceeding the 70th percentile in each subgroup predicted AEs with a sensitivity of 65.4%. An unadjusted QRSd criterion showed the same overall sensitivity and specificity but with less uniform values for each subgroup. A Cox model was constructed by use of multiple prognostic indicators, and in rank order, QRSd, previous MI, and Killip class were predictive of AEs. CONCLUSIONS: SAECG adjustments for sex, age, and MI location did not improve sensitivity and specificity but produced a more uniform predictive performance. The proposed criteria are based only on QRSd, because late potentials (VRMS and LAS) did not discriminate patients with sudden death. Duration of high-level activity during QRS (QRSd-LAS) can predict AEs, suggesting that the arrhythmogenic substate involves a large mass of myocardium.

Age Factors↗
PubMed1997

Phototoxicity in quinolones: comparison of ciprofloxacin and grepafloxacin.

Skin photosensitizing reactions have been reported during treatment with fluoroquinolone antibiotics. The incidence and severity of such reactions, however, appear to differ between agents. The photosensitizing effect of grepafloxacin 400 and 600 mg once daily was compared with that of ciprofloxacin 500 mg bd and placebo in a double-blind trial involving 32 healthy subjects. Skin photosensitivity, expressed as the minimal erythemal dose (MED), was measured before treatment and towards the end of the 7 day treatment period. Grepafloxacin showed a mild photosensitizing effect comparable to that of ciprofloxacin, with significant reductions in MED at 335+/-30 and 365+/-30 nm. However, few subjects showed MEDs outside the normal range, and MEDs consistently returned to baseline values within 1 week of stopping treatment. No significant differences between the effects of grepafloxacin and ciprofloxacin could be observed. It is concluded that grepafloxacin has a weak, UVA-dependent and rapidly reversible photosensitizing effect.

Adolescent↗
PubMed1997

Dimensions of pain and analgesic administration associated with coronary artery bypass grafting in an Australian intensive care unit.

This descriptive correlation study evaluated the pain intensity, pain distress and morphine consumption in patients recovering from coronary artery bypass grafting (CABG) surgery in an Australian intensive care unit (ICU) and compared patients' pain intensity ratings with ratings of the nursing staff. Forty-three patients and their attending nurses rated patients' pain intensity and pain distress levels at 8-hourly intervals throughout their stay in ICU. A maximum of five assessments was obtained in the first 48 post-operative hours from patients and their nurses. Pain intensity and pain distress were measured using separate 10-point numerical rating scales (NRS). Patients' worst pain intensity scores increased over time in ICU; the amount of opioids they received was small and decreased over time. Significant differences occurred between patients' and nurses' average pain intensity scores at each time point and, except for worst pain intensity measures at the first assessment, nurses consistently underestimated patients' pain. These results indicate that patients in ICU following CABG can experience considerable pain, which is not always relieved. The application of regular systematic pain assessment and improved communication, together with the administration of adequate pain relief are necessary if nurses are to manage patients' pain effectively.

Analgesics, Opioid↗
PubMed1997

Is patch testing necessary in vulval vestibulitis?

Allergic contact dermatitis has been suggested as a possible cause of vulval vestibulitis, a condition of unknown aetiology characterized by burning, stinging and dyspareunia, with symptoms localised to the vestibule. To examine this relationship, 30 women with vulval vestibulitis were patch tested using a standard series of contact allergens and a special series relevant to perianal and vulval disorders. Other potential allergens identified by the patients as causing aggravation were also included. There were 5 positive reactions, 4 to nickel and 1 to fragrance mix, though none of these reactions were considered relevant. Our results suggest that allergic contact dermatitis is unlikely to be a primary factor in the development or persistence of vulval vestibulitis. Patch testing patients with vulval vestibulitis cannot routinely be recommended.

Administration, Cutaneous↗
PubMed1997

Prolonged benefit following ultraviolet A phototherapy for solar urticaria.

Two patients with severe idiopathic solar urticaria, previously resistant to a variety of therapies including plasma exchange, benefited from springtime courses of ultraviolet A (UVA) monotherapy. Sites which are normally exposed to sunlight were treated, in a cabinet fitted with Philips R-UVA lamps (emitting UVA and visible wavelengths, with peak at 350 nm), twice daily for 2-3 weeks. One patient has been treated in this way for 3, and the other for 2, consecutive years. Repeat monochromator phototesting 3 months after their latest courses of UVA showed a persistent reduction in severity of abnormal photosensitivity. Both patients describe a sustained improvement in their condition lasting over 6 months after treatment.

Adult↗
PubMed1996

Insertion and orientation of a synthetic peptide representing the C-terminus of the A1 domain of Shiga toxin into phospholipid membranes.

Shiga toxin is a bacterial protein composed of one A and five B subunits. Its A chain possesses a protease sensitive loop (Cys-242-Cys-261) that is cleaved to produce an enzymatically active A1 domain and an A2 fragment associated with its B subunit pentamer. The proposed mode of action of the toxin is linked to its retrograde transport to the ER lumen followed by the translocation of its catalytic A1 chain to the cytoplasmic side of the ER membrane. A signal sequence-like domain (residues 220-246) which constitutes the C-terminus of the A1 chain precedes a region within the protease sensitive loop (residues 247-258) that contains known and putative cleavage sites. Two peptides corresponding to this C-terminus (residues 220-246) were chemically synthesized to investigate if this signal sequence-like domain can interact with membranes. Such a property may provide a clue to the mechanism of translocation of the A1 domain across the ER membrane. The first peptide represented the native sequence, which includes a naturally occurring cysteine at position 242 and provided a thiol moiety for the attachment of a spinlabel. A second peptide was designed to contain a single tryptophan residue (Ile232Trp) located within the hydrophobic core of the sequence which served as an intrinsic fluorescence probe. The interactions of both peptides with lipid vesicles were analyzed by circular dichroism, fluorescence, and EPR spectroscopy. The peptides lack structure in aqueous buffers and adopted an alpha-helical geometry when bound to negatively charged lipid vesicles. The addition of lipid vesicles to a solution of the tryptophan-containing peptide results in a blue shift in the wavelength of its fluorescence maxima as well as an increase in fluorescence intensity at 335 nm, suggesting that the hydrophobic core of this A1 peptide relocated to a nonpolar environment. EPR measurements of a proxyl-labeled analog of the peptide (introduced at Cys-242) indicated a decreased mobility of a fraction of the proxyl probe in the presence of lipid vesicles. At pH 7, the membrane-bound probe was completely reduced by ascorbate trapped inside vesicles but only partially reduced by ascorbate added outside the vesicles, suggesting that the C-terminal region of the peptide traversed the membrane bilayer or relocated close to the surface of its inner lipid leaflet. Finally, the peptide was shown to insert into lipid vesicles, causing the release of calcein at a high peptide:lipid ratio. These results suggest that the C-terminal tail of the A1 chain may anchor this domain into the ER membrane.

Amino Acid Sequence↗
PubMed1996

Pharmacodynamics of torsemide administered as an intravenous injection and as a continuous infusion to patients with congestive heart failure.

The natriuretic and diuretic effects of a 100-mg dose of torsemide administered as a continuous infusion of torsemide and as a single bolus were compared in a group of patients with stable mild-to-moderate congestive heart failure (CHF). Patients received in random order 100 mg of torsemide as an intravenous bolus and as a 75-mg infusion over 24 hours started simultaneously with a 25-mg loading bolus. Administration of torsemide to patients with CHF as a continuous infusion was an effective dosing regimen, resulting in 24-hour diuresis and natriuresis that was numerically but not statistically greater than that observed with bolus administration. The response with continuous infusion occurred with less torsemide in the urine, resulting in a significantly greater efficiency of torsemide with this regimen. The effectiveness of torsemide as a continuous infusion does not mean that this mode of administration should be used in all patients. The response to 100 mg of torsemide in patients with mild-to-moderate CHF is the same whether administered as an intravenous bolus, a continuous intravenous infusion, or by mouth. This is consistent with the high bioavailability demonstrated in previous studies. The mode of therapy used should be dictated by each individual patient's needs. This study shows that continuous infusion is a viable option for administration of torsemide, and dosing guidelines for use of such a strategy are presented.

Adult↗