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Biomedical subjects

R Farrell

Publications and source records attributed to R Farrell.

At least 19 recordsLinked to original sources
PubMed1998

Claudication on mastication following bilateral external carotid artery ligation for posterior epistaxis.

This case highlights a potentially disabling complication of intermittent claudication in the region of the masseter muscles on mastication, following bilateral external carotid artery ligation for epistaxis. Although there have been few reports of this complication this may be a reflection of the fact that the operation is rarely performed, and not because the complication is rare. Its potentially disabling nature, and its possible common occurrence after this procedure make awareness of it by surgeons who may carry out this procedure important.

Carotid Artery, External↗
PubMed1997

The clinical role of shoulder ultrasound.

BACKGROUND: Rotator cuff surgery is facilitated by accurate pre-operative information regarding the presence and size of cuff tears, and the extent of any cuff retraction or lamination. METHODS: A total of 117 consecutive patients who underwent shoulder ultrasound followed by surgical management were assessed, and the pre-operative ultrasound diagnoses were correlated with the operative findings. RESULTS: Ultrasound was found to be reliable for the detection of full-thickness cuff tears (positive predictive value 96%). In the assessment of partial thickness tears, ultrasound produced few false positives, but failed to diagnose a significant proportion of these lesions. Lamination and other interstitial cuff pathology were not reliably detected by ultrasound. In the diagnosis of subacromial impingement, ultrasound produced few false positives (positive predictive value 95%), but did produce a significant number of false negative results (negative predictive value 66%). CONCLUSIONS: Ultrasound is cheaper than MRI and arthrography, and is both non-invasive and 'dynamic'. It is reliable in the diagnosis of full-thickness cuff tears and is a useful adjunct in the diagnosis of cuff impingement and partial thickness tears, but is very much operator-dependent.

Adolescent↗
PubMed1995

Levels of superoxide dismutase mRNA in rat lens: effect of aging.

Superoxide dismutase, the enzyme catalyzing the dismutation of O2.- to H2O2 is known to be present in various ocular and nonocular tissues. In this communication we have determined the gene expression of this enzyme in rat lenses. The investigations have been conducted as a function of age using RNase protection assay. These in vitro assays for the corresponding mRNA suggested that the transcription of the gene is age variant, increasing as a function of age. The levels were significantly lower in the young lenses in comparison to the older lenses.

Aging↗
PubMed1993

Protocols for college health nurses: alive and well in the 1990s.

This article seeks to assist college health nurses in developing appropriate protocols for patient care. In addition, the authors outline factors influencing protocol content, design, and development and describe steps in creating individualized protocols by practice setting. To provide college health nurses with a basic understanding of protocols, the authors offer definitions and examples of appropriate and inappropriate use, and show how protocols can influence the delivery of patient care. Although protocols may provide college health nurses with directives for managing specific health problems, they require a sophisticated level of judgment and skill in their implementation.

Female↗
PubMed1985

Heparin and dihydroergotamine prophylaxis against thrombo-embolism after hip arthroplasty.

A prospective study involving 500 consecutive patients undergoing hip replacement was performed to find out whether a combination of heparin and dihydroergotamine was effective in preventing postoperative fatal and non-fatal emboli. Deep-vein thrombosis was demonstrated in 131 cases (26.2%), in 99 of whom thrombi were confined to the ipsilateral (operated) limb and in 13 to the contralateral limb; 19 patients developed bilateral thrombi. Nine patients (1.8%) died during the first four weeks after operation, before they were discharged from hospital; in one, major emboli were demonstrated in the right pulmonary artery. Three of the 500 patients developed non-fatal pulmonary emboli. Excessive bleeding occurred in 21 (4.2%) and in 19 of these prophylaxis was discontinued. Wound haematomas developed in 25 patients (5.0%); only six required evacuation but in none of these six did deep infection occur while in hospital; in three patients, however, the wound haematoma prolonged the stay in hospital. Thus the combination of heparin and dihydroergotamine proved an effective prophylaxis against pulmonary embolism in patients undergoing total hip replacement. The risk of bleeding complications is wholly acceptable when balanced against the advantages of the therapy.

Aged↗
PubMed1985

Free radicals appear to affect survival of hepatocytes at 4 degrees C.

1) Rat hepatocytes, stored in a simple salts medium for 24 h at 4 degrees C, retain more than 80% of their capacity to synthesize glucose from lactate. 2) The combination of NH4Cl with oleate is cytotoxic during storage and during subsequent incubation of hepatocytes from 48 h starved rats, but not to hepatocytes from fed rats. 3) Protection against cytotoxicity is afforded by albumin and by a number of other compounds, notably polyols and glycerol. 4) These compounds appear to exert their effects by scavenging free radicals and, in the case of polyols and glycerol, by supplying reducing equivalents to maintain the redox state of the cell in the face of increased flux through glutathione peroxidase.

Ammonium Chloride↗
PubMed1983

Measurement of steady state protein degradation in cultured human muscle cells.

Double label techniques for measurement of protein turnover in cultured cells are described. In the isotope withdrawal method protein in cultured muscle is labeled with two isotopes of the same amino acid for 24 to 100 h, followed by exposure to fresh medium containing one isotope only at the same specific activity for an additional 24 to 48 h. In the isotope addition method the order of addition of single and double-labeled media is reversed. After incubation the ratio of the two isotopes in the cell protein is a function of the incubation time and the degradation rate constant KD; KD can readily be calculated using a graphical or iterative method. In mixed cultures of human muscle with initial incubation ranging 24 to 159 h, the KD's obtained from various incubation times were similar. Both the isotope withdrawal and the isotope addition methods gave a KD value of 0.018 h-1 similar to values obtained by two different single isotope methods which monitor the appearance of free isotope in the medium of previously labeled cells. There were no differences of KD values obtained in cultures of muscle from normal patients and those with denervation, inflammatory myopathies, or nonspecific myopathic biopsy changes. When proteins were separated by gel electrophoresis, those of molecular weight greater than 60,000 had higher average KD values as compared to lower molecular weight proteins. The double isotope labeling method has the advantage of being easily applied to cultures with small numbers of cells and is potentially useful in obtaining the degradation rates of individual cellular proteins. The major disadvantages are (1) in their present form the methods can be used only in steady state cultures and (2) they require rather long (24 h) labeling times.

Cells, Cultured↗
PubMed1983

Effect of starvation and refeeding on polyamine concentrations and ornithine decarboxylase antizyme in mammary gland of lactating rats.

Starvation caused a marked increase in putrescine content in mammary gland of lactating rats, together with a marked decrease in activity of ornithine decarboxylase and appearance of measurable ornithine decarboxylase antizyme. 2. Refeeding for 5 h caused disappearance of free antizyme and ornithine decarboxylase activity returned to the value in fed animals. Putrescine concentration remained elevated. 3. There was no significant change in nucleic acid content of mammary gland from starved rats, but spermidine and spermine contents increased significantly. 4. Refeeding for 5 h returned the spermidine content of mammary glands to 'fed' values, and significantly decreased the content of spermine, although it did not reach control values. Thus changes in polyamine content of mammary gland in starved rats are clearly dissociated from changes in either RNA content or activities of polyamine-synthetic decarboxylases. 5. Starvation caused a fall in the content of spermidine in liver, with no change in spermine content. Refeeding for 5 h returned the spermidine content to 'fed' values.

Animals↗
PubMed1982

Effects of inhibition of protein synthesis by cycloheximide on lipogenesis in mammary gland and liver of lactating rats.

1. Administration of cycloheximide (an inhibitor of protein synthesis) to lactating rats raised the concentrations of amino acids, and in particular, the branched-chain amino acids (valine, leucine and isoleucine) in blood, liver and mammary gland. 2. Inhibition of protein synthesis increased the incorporation in vivo of L-[U-14C]leucine into lipids of mammary gland and liver. 3. Cycloheximide treatment caused no immediate change in the overall rate of lipogenesis in vivo (measured with 3H2O) in mammary gland but increased the rate in liver 3-fold; this latter effect also occurred in livers of virgin rats. 4. The increased rate of hepatic lipogenesis was not accompanied by significant changes in the plasma insulin concentration or the activity of acetyl-CoA carboxylase. 5. Although cycloheximide decreased the entry of total triacylglycerol into the circulation it did not alter the rate of secretion of newly synthesized saponifiable lipid. 6. Cycloheximide slightly stimulated lipogenesis from endogenous substrates in isolated hepatocytes, but this effect was abolished when lactate was the exogenous substrate. 7. Administration of cycloheximide to virgin rats decreased liver glycogen and increased the hepatic content of glucose 6-phosphate, pyruvate and lactate. 8. It is concluded that (a) there is no short-term link between the rate of protein synthesis and lipogenesis in the lactating mammary gland and (b) the increased rate of hepatic lipogenesis in cycloheximide-treated rats is mainly due to stimulation of glycogenolysis, glycolytic flux and consequent increased availability of pyruvate.

Animals↗
PubMed1981

Brain site variations in effects of morphine on electrical self-stimulation.

Pairs of bipolar electrodes were stereotaxically aimed at two of three sites: the locus coeruleus (LC), the substantia nigra, pars compacta (SNC), and the median forebrain bundle (MFB). Rats were shaped to bar-press for trains of intracranial electrical stimulation presented as pairs of monophasic pulses. The first pulse of a pair (the C, conditioning pulse) was followed by a second pulse (the T, test pulse) after a parametrically varied interval. The effects of chronic morphine administration were tested in a paradigm of 7 days saline, 7 days morphine, 1 day morphine+naloxone, and 6 days post-drug saline. High doses of morphine (5 mg/kg) depressed response rates for intracranial self-stimulation (ICSS). LC placements and those just lateral or ventral to the LC showed large increases in ICSS rates under morphine (2.5 mg/kg). This area was delimited on either side by tips that showed response rate depressions under morphine. MFB placements yielded response rate facilitations under morphine. Sites medial to the MFB and ventral within the MFB showed rate depressions under morphine. Dorsal substantia nigra placements showed facilitated rates, whereas placements ventral within the SNC and substantia nigra, pars reticulata (SNR) produced more variable results, with rates tending to be depressed by morphine. The ICSS procedure may be a useful animal model for detecting the abuse potential of drugs.

Animals↗
PubMed1980

The removal of infused leucine after injury, starvation and other conditions in man.

1. To investigate the effects of starvation, elective surgery, accidental injury and other clinical conditions on the metabolism of branched-chain amino acids in man, we have measured the basal concentration of leucine and the removal of metabolic effects of infused L-leucine. 2. The blood concentration of leucine as significantly increased by surgery, starvation and accidental injury, and decreased in cirrhosis. It tended to increase in diabetes and was unaffected by muscular dystrophy. 3. The half-life of infused leucine was nearly doubled by 4 days of complete starvation, unaltered by surgery and decreased by severe accidental injury, Infusion with Intralipid, which increased free fatty acid and ketone-body concentrations, had no effect on the removal of a leucine load. The clearance rate of infused leucine was reduced in diabetes and muscular dystrophy and increased in cirrhosis. 4. The effects of infused leucine on blood glucose and ketone bodies differed according to the groups studied. 5. Since the traumatized patients were given sufficient energy and nitrogen and disposed of a leucine load at a different rate from the starved patients, the causes of the increase in blood concentration of leucine in these two conditions are different.

Adolescent↗
PubMed1980

Corneal swelling at low atmospheric oxygen pressures.

Corneas of 28 human subjects were exposed to oxygen partial pressures, in a gas goggle, of either 6.9, 17.1, or 22.2 mm Hg, and the corneal swelling was measured by pachometry for 4 hr. Following an initial rise, the swelling stabilized after about 3 hr; in many subjects it was reversed, indicating an adaptation process. The average corneal swelling after 4 hr for the three oxygen partial pressures was 5.07%, 2.13%, and 1.66%, respectively. The average minimum oxygen requirement to prevent corneal swelling was at least 23 mm Hg and varied significantly among individuals. The variations in swelling responses were large enough to explain clinical differences in edema of patients wearing oxygen-permeable contact lenses, in the absence of adequate tear pumping.

Adaptation, Physiological↗
PubMed1977

Muscle-protein catabolism after injury in man, as measured by urinary excretion of 3-methylhistidine.

1. Urinary excretion of 3-methylhistidine, an index of the rate of muscle breakdown, has been measured during the first 7 days in patients after elective surgery or accidental injury. 2. There was no major difference between the mean daily excretion after skin grafting or total hip replacement, or in injured patients who were hyperketonaemic for the first 24 h after admission. 3. The group of injured patients who did not develop hyperketonaemia had a mean urinary 3-methylhistidine excretion which was twice that of the other groups. 4. It is concluded that increased breakdown of muscle protein makes a major contribution to the greater urinary nitrogen excretion in the normoketonaemic group of injured patients.

Adolescent↗
PubMed1976

Branched-chain amino acids, nitrogen excretion and injury in man.

1. Venous blood concentrations of the branched-chain amino acids, valine, leucine and isoleucine, and urinary nitrogen excretion have been measured in sixteen adult males, from 2 h to 7 days after injury, and in four adults after elective skin grafts. 2. In the injured group the concentrations of these amino acids rose significantly 24 h after injury and had doubled at 4 days and remained high; in contrast the skin-graft patients showed no significant change. 3. In those injured patients with initial hyperketonaemia, defined as more than 0-2 mmo1/1, the increase in concentrations of branched-chain amino acids at the fourth and seventh days after injury was significantly less than in those with normoketonaemia, and was accompanied by lower urinary nitrogen excretion throughout the whole period. 4. It is suggested that the changes in the concentration of branched-chain amino acids after injury indicate decreased uptake by muscle or excessive release due to an imbalance between protein synthesis and protein catabolism in this tissue.

Adolescent↗
PubMed1976

Colonoscopy associated bacteremia.

Fifty-two patients undergoing uneventful diagnostic colonoscopy with or without polypectomy and biopsy were evaluated for evidence of bacteremia during and after the procedure. In only two instances was bacteremia noted. Positive findings were noted in patients with carcinomatosis and severe liver involvement. These data suggest that routine prophylactic antibiotic coverage is unnecessary in uncompromised patients. Further studies are warranted when patients have either severe liver involvement or impairment of normal host defense mechanisms.

Adult↗