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Biomedical subjects

Q G Forrest

Publications and source records attributed to Q G Forrest.

4 recordsLinked to original sources

Mass confusion.

A patient is reported who presented to the hospital with a benign arrhythmia and what was initially believed to be a benign intracardiac tumour as imaged by transthoracic echocardiography and a first transesophageal echocardiogram. Comprehensive assessment with a second transesophageal echocardiogram revealed extensive extra- and intracardiac involvement by masses with many malignant-appearing features, including compression of vascular structures in the mediastinum. Peripheral biopsy yielded a diagnosis of high-grade lymphoma. The clinical, echocardiographic and radiological findings are discussed, as are the expected features of myxomae, and by comparison, common features of malignancy. The ability of transesophageal echocardiography, when comprehensively performed, to define the location and extent of mass lesions, and their physiological impact, such as compression of the pulmonary vasculature, by two-dimensional imaging and spectral Doppler are emphasized.

Diagnosis, Differential↗

Effects of 3 analgesic regimens on the perception of pain after removal of femoral artery sheaths.

BACKGROUND: Effective pain management after removal of femoral artery sheaths after percutaneous transluminal coronary angioplasty is highly individualized and requires frequent, accurate assessment and administration of analgesics as needed. OBJECTIVE: To determine which of 3 analgesic regimens is most effective in decreasing patients' perception of pain with the fewest side effects after removal of a femoral artery sheath. SAMPLE: 130 adult who had undergone percutaneous transluminal coronary angioplasty and were in an 8-bed cardiac short-stay unit in a 1400-bed acute care hospital. METHOD: Patients were randomized to receive either intravenous morphine, intravenous fentanyl, subcutaneous lidocaine around the sheath site, or an intravenous placebo before sheath removal. Rescue analgesia (intravenous fentanyl) was made available to all groups. Patients used a visual analog scale to assess pain within 10 minutes before, 1 minute after, and 20 minutes after sheath removal. Pain levels, frequency of side effects, and use of rescue analgesia were compared among groups. RESULTS: Age, sex, number of stents, and frequency of hematomas did not differ significantly among groups. Pain ratings, use of rescue analgesia, and side effects (nausea, vomiting, or vasovagal symptoms) were not significantly different among treatment groups. Ratings of pain were slightly higher immediately after sheath removal in all groups. CONCLUSION: For most patients, removal of femoral artery sheaths and manual compression for hemostasis are relatively pain-free. Pain scores among patients given analgesia with subcutaneous lidocaine, intravenous morphine, or intravenous fentanyl were not significantly different from pain scores among control patients.

Adult↗

Non-uniform ion distributions and electrical potentials in sarcoplasmic regions of skeletal muscle fibres.

We report here electrophysiological and ion distribution results obtained with mechanically skinned skeletal muscle fibres which indicate that a Donnan equilibrium, characterized by large ionic concentration and electrical potential differences, is established between the myofibrillar space and the rest of the sarcoplasm surrounding the myofibrils. The more negative electrical potential within the myofibrils (-15 to -29 mV for conditions similar to those in vivo) can strongly influence: (1) intracellular Ca2+ movements associated with contraction; (2) the location of sarcoplasmic enzymes, their substrates and products of reaction; (3) measurements of the electrical potential difference between the extra- and intracellular space and estimation of relative membrane permeabilities for certain ions.

Animals↗

Different isometric force - [Ca2+] relationships in slow and fast twitch skinned muscle fibres of the rat.

Skinned muscle fibres prepared from fast and slow twitch muscles of rat have been activated in Ca2+-buffered solutions using a new activation procedure (Moisescu, D.G. and Thieleczek, R. (1978) J. Physiol. 275, 241--262). The results indicate that (i) the Ca2+ activation curve is less steep for slow fibres, (ii) physiologically relevant force levels are attained considerably faster at constant [Ca2+] in fast fibres, and (iii) active force becomes noticeable at lower [Ca2+], but reaches saturation at higher [Ca2+] for slow fibres.

Animals↗