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Biomedical subjects

J McCarthy

Publications and source records attributed to J McCarthy.

At least 199 records · Page 11Linked to original sources
PubMedDate not supplied

Use of firefly luciferase for ATP measurement: other nucleotides enhance turnover.

Firefly luciferase utilizes only ATP and a few closely related nucleotides as substrates for the formation of luciferyl adenylate which is an intermediate in the bioluminescent reaction sequence that oxidizes firefly luciferin. The enzyme shows two different time courses of light production depending on ATP concentration used: a flash with high concentrations of ATP (> 8 microM) or a fairly constant production of light with lower concentrations of ATP (< 1 microM). Many nucleotides, nucleotide-containing substances and other compounds, when added either prior to or 1 min after the addition of ATP, change the time course of light production. When added before ATP, these compounds yield a reaction mixture in which light production is fairly constant (at the level characteristic of the flash observed with that ATP concentration). When the compounds are added after ATP addition, light production is markedly stimulated and the higher rate of light production is maintained for several minutes. There is an increase in quanta of light produced per luciferase dimer from 1 to 5/min with the addition of any of several nucleotide analogues. These results are consistent with a stimulated release of the inhibitory product oxyluciferin, allowing turnover of the enzyme. This enzyme turnover permits more light output at high ATP concentrations, thus enhancing the sensitivity of enzyme determination.

Adenine Nucleotides↗
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Putting research into practice.

Two nursing units at the James A. Haley Veterans' Hospital in Tampa, FL, used a model directed toward translating research outcomes into clinical knowledge for use in a practice setting. Each unit developed its own unique subjects, based on problem identification by the nursing staff. The clinical areas followed different courses, and the results varied. Many differences between the two units became apparent, such as mode of delivery of nursing care (primary versus team nursing) and differences in staffing patterns. These differences had an impact on successful implementation of the model. This article describes the Conduct and Utilization of Research in Nursing (CURN) model as a process that guides nursing staff in integrating research and clinical practice.

Humans↗
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Composition and stress analysis in Si structures using micro-raman spectroscopy.

Strained silicon (Si) technology enables improvements in complementary metal oxide semiconductor (CMOS) performance and functionality via replacement of the bulk, cubic-crystal Si substrate with an Si substrate that contains a tetragonally distorted, biaxially strained Si thin film at the surface. Here we use Raman spectroscopy to allow us to characterise growth processes of strained si, and to characterise the resulting level of strain/stress in the si and the effect it has on the underlying layer of graded SiGe.

Journal Article↗
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Cyclic AMP mediated arrhythmias induced in the ischaemic pig heart.

Ligation of the anterior descending coronary artery two-thirds from its origin in the pig was found to precipitate ventricular arrhythmias and fibrillation, starting approximately 20 min post-ligation, which were associated with regional accumulation of myocardial cAMP in the ischaemic area. When the arrhythmias stopped, cyclic AMP levels in the ischaemic zone were decreased. Arrhythmias could then be induced by subepicardial infusion (10 microliter/min) close to the visible edge of ischaemia of cAMP analogues [N6-monobutyryl cAMP, N6,O2'-dibutyryl cAMP (5.10(-2) M each)] or agents which increase the myocardial contents of cAMP. These agents were: isoproterenol (10(-6) M), noradrenaline, adrenaline (10(-5) M each), glucagon, histamine (10(-3) M each), theophylline and caffeine (5.10(-2) M each). Also active were dopamine (10(-3) M), ouabain (10(-5) M) and aconitine (10(-6) M). The arrhythmias induced by infusion of catecholamines were dependent on Ca2+ and were abolished by beta-adrenoceptor blocking agents (pindolol, 10(-6) M) and calcium antagonists (isoptin, D 600, 10(-4) M each). Infusion of 150 mM sodium chloride or 100 mM sodium butyrate did not precipitate arrhythmias. It is concluded that myocardial cAMP may play an important role in the genesis of ventricular arrhythmias in the ischaemic heart, probably by augmenting the slow calcium inward current.

Adrenergic beta-Antagonists↗
PubMedDate not supplied

The first 20 years of heart transplantation in Ireland.

BACKGROUND: The first Irish heart transplant was performed on the 10th of September 1985. Over the next 20 years, 229 transplants were performed in 228 recipients. AIMS: To evaluate the success of the first generation of cardiac transplantation in Ireland. METHODS: Analysis of clinical outcomes and survival statistics for patients undergoing heart transplantation in Ireland and comparison with international standards. RESULTS: There has been a steady improvement in transplant outcome over this time and survival figures for recipients between 2000 and 2004 show a hospital, 1-year and 5-year survival rate of 85.7%, 84.1% and 76.8% respectively. Thirty-eight of the 99 heart transplants performed between 1985 and 1994 are still alive more than 10 years later and the longest survivor is now 19 years post transplantation. CONCLUSIONS: The results compare favourably with international figures. Heart transplantation offers excellent longterm survival and quality of life but remains challenged by a shortage of suitable donor organs.

Adolescent↗
PubMedDate not supplied

Computed tomographic demonstration of colonic carcinoma metastatic to the spleen.

Metastasis to the spleen is a very uncommon medical entity. The author reports on unusual case of splenic metastasis originating from carcinoma of the colon demonstrated by computed tomography of the abdomen. The metastases appear as low density space occupying lesions which is a characteristic appearance seen in other metastases to the spleen.

Adenocarcinoma↗
PubMedDate not supplied

Preliminary experience with endoscopic stent placement in benign pancreatic diseases.

We treated 35 patients with endoscopic stent placement across the major or minor papilla in an attempt to relieve suspected partial obstruction to pancreatic duct drainage in patients with pancreatitis. The patients subsequently have been followed for periods ranging from 6 months to 3 years (mean, 14 months). Endoscopic stents were successfully placed across the minor papilla in 19 of 22 patients with pancreas divisum associated with acute recurrent pancreatitis (19) and severe abdominal pain (3). 17 patients had symptomatic improvement manifested by a decrease in frequency of attacks of pain and emergency admission. Stents were placed through the major papilla in 14 of 15 patients with recurrent pancreatitis related to a variety of causes. 8 of the 14 patients improved during the follow-up period, including 4 of 5 patients with alcoholic pancreatitis complicated by a segmental stricture.

Cholangiopancreatography, Endoscopic Retrograde↗
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Adequacy of disposable biopsy forceps for gastrointestinal endoscopy: a direct comparison with reusable forceps.

Disposable plastic biopsy forceps were compared prospectively to reusable stainless steel forceps. Thirty consecutive patients underwent a total of 249 biopsies, 124 with the disposable forceps, and 125 with reusable forceps. Biopsy locations included the esophagus, stomach, small intestine, colon, and common bile duct. Specimens were compared microscopically to determine overall surface area, depth, adequacy, and diagnostic result. The disposable biopsy forceps yielded specimens which were 37% smaller when compared with the reusable forceps. In five of the comparisons, minor differences in histological findings were noted between the two groups of biopsy specimens, but these differences did not alter the pathological diagnosis. However, in three cases in which superficial specimens were obtained, an underlying carcinoma was missed with the disposable forceps. Our study documents the utility of disposable biopsy forceps for mucosal lesions. In addition, there were 11 mechanical failures in 38 biopsy attempts with the plastic biopsy forceps. These forceps appear to be limited in their capacity to obtain adequate specimens from firm tissue or when submucosal biopsy samples are required, and they will require refinements in design to duplicate specimen quality obtained by traditional reusable forceps. Disposable forceps are particularly suitable for biopsy of mucosal lesions in patients with possible communicable disease, and they should help to reduce cross-contamination in the gastroenterology laboratory.

Biopsy↗
PubMedDate not supplied

Topological disorder in peripheral vision.

One of the most striking properties of the mammalian visual system is that it is only the central part of the visual field, the fovea, where vision is most acute. The superiority of the fovea is particularly evident in tasks requiring accurate spatial localization. It is currently thought that peripheral spatial uncertainty is a simple consequence of the decreased sampling grain of the peripheral field. We show that the topological fidelity of the afferent projection declines with eccentricity away from the fovea and that it is this rather than the sampling grain that underlies the poorer performance of the periphery in tasks involving spatial localization. The combination of normal sampling and a disordered topology results in the periphery having good sensitivity for detection but poor sensitivity for object recognition.

Fovea Centralis↗
PubMedDate not supplied

Immunoadsorption for coagulation factor inhibitors.

Inhibitors to coagulation factors are among the most difficult problems in the management of coagulation disorders. Most presently available therapy does not assure hemostasis. An extracorporeal immunoadsorption system, which selectively binds IgG, was used to lower inhibitor levels in eight patients on 10 occasions. In this system, separated plasma is delivered to two staphylococcal protein A-Sepharose columns, which are coupled to an elution monitor. Columns are eluted sequentially and regenerated to maximize IgG removal. Successful removal of the inhibitor was accomplished in all six hemophiliacs on seven occasions, as well as in a patient with acquired von Willebrand disease. All patients whose inhibitors were lowered to less than 10 Bethesda units achieved measurable factor levels when factor concentrate replacement was given. Immunoadsorption facilitates efficient removal of inhibitors, which allows factor replacement therapy.

Adult↗
PubMedDate not supplied

Quantitative urine drug monitoring in methadone programs: potential clinical uses.

An on-site clinical laboratory in a methadone program can provide semiquantitative urine drug monitoring by using fluorescence polarization immunoassay (FPIA) technology. This report documents a wide range of urine drug levels from threshold to near 2,000,000 ng/ml in this patient population, suggesting how laboratory measures can assist in assessing the severity of addiction. Urine drug level data are reported for drugs of abuse (opioid, amphetamines, cocaine) as well as therapeutic drugs (benzodiazepines and methadone). Clinical uses of quantitation illustrated include screening of all admissions prior to induction on methadone, identification of unusually heavy users, monitoring drug washout, and assessing compliance with prescribed benzodiazepine and methadone regimens. The Clinical Laboratory Improvement Act (CLIA88) has set national certification standards for moderate complexity laboratories using immunoassays and set up a mechanism for monitoring quality in such clinic-based laboratories.

Amphetamine↗
PubMedDate not supplied

Aeromedical trauma sonography by flight crews with a miniature ultrasound unit.

BACKGROUND: While ultrasound has become an established diagnostic modality in trauma care, no study has evaluated its use in the prehospital setting. OBJECTIVE: To examine the use of the focused abdominal sonography for trauma (FAST) exam in the prehospital setting. METHODS: After a three-hour training session in the FAST exam, the nonphysician flight team of an emergency medical services (EMS) helicopter program attempted a FAST exam on trauma patients to determine the feasibility of such an intervention. RESULTS: The majority (83%) of the 71 patients entered suffered blunt trauma. FAST exams could not be performed in 34 patients (48%) due to insufficient time (67%), inadequate patient access, or combativeness. Technical difficulties (difficult screen visualization due to ambient lighting, battery failure, and machine malfunction) prevented scanning in seven (19%) of the 37 in whom it was attempted. In those in whom scanning was successful, the pelvic view was most commonly obtained followed by the right upper quadrant (RUQ) and left upper quadrant (LUQ). CONCLUSION: Significant advances in training, technology, and/or patient access will be necessary for aeromedical FAST to be feasible.

Abdominal Injuries↗
PubMedDate not supplied

Increased glycolysis during ischaemia mediates the protective effect of glucose and insulin in the isolated rat heart despite the presence of cardiodepressant exogenous substrates.

BACKGROUND: Exogenous insulin is known to protect against ischaemia-reperfusion injury of the myocardium. We investigated whether these benefits of insulin could be explained by increased glycolysis during the ischaemic period, even in the presence of potentially cardiodepressant substrates such as fatty acids and lactate. Increased cardiac output during post-ischaemic reperfusion was used as a marker of protection by insulin. METHODS: Isolated hearts from fasted rats were subjected to 5 minutes of Langendorff perfusion followed by a 15-minute working heart pre-ischaemic perfusion with glucose (11 mmol/l), followed by a 30-minute 0.2 ml/min low-flow Langendorff ischaemic period, using glucose(11 mmol/l) or glucose plus fatty acids (1 mmol/l), or lactate (10 mmol/l), or lactate plus glucose as substrates. During reperfusion, the hearts were again perfused with glucose. Insulin (1 mU/ml), when added, was present throughout the experimental protocol. RESULT: Post-ischaemic reperfusion cardiac output recovery was depressed in hearts perfused with glucose plus fatty acids or with lactate alone, when compared with glucose alone (p<0.01). In each case, cardiac output improved (p < 0.01) with insulin pre-treatment despite added fatty acids, or in hearts perfused with lactate alone during ischaemia. Improved cardiac output could be linked to improved glucose uptake (p < 0.05) during ischaemia and increased pre-ischaemic glycogen stores (p < 0.01). In hearts perfused with lactate alone, increased glycolysis occurred via glycogen breakdown as confirmed by increased cardiac tissue lactate levels at the end o the ischaemic period. CONCLUSION: Insulin treatment before ischaemia and throughout ischaemia and reperfusion, abolished the depressant effects of fatty acids added to glucose or of lactate alone, on reperfusion cardiac output. The consistent feature common to the protective effects of insulin in the various conditions tested was increased glycolysis, whether achieved by increased glucose uptake during the ischaemic period or by glycogen preloading. Increased glycolysis could also explain the protective effect of glucose added to lactate in the absence of insulin.

Analysis of Variance↗
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A framework for analyzing the determinants of maternal mortality.

Hundreds of thousands of women in developing countries die each year from complications of pregnancy, attempted abortion, and childbirth. This article presents a comprehensive and integrated framework for analyzing the cultural, social, economic, behavioral, and biological factors that influence maternal mortality. The development of a comprehensive framework was carried out by reviewing the widely accepted frameworks that have been developed for fertility and child survival, and by reviewing the existing literature on maternal mortality, including the results of research studies and accounts of intervention programs. The principal result of this exercise is the framework itself. One of the main conclusions is that all determinants of maternal mortality (and, hence, all efforts to reduce maternal mortality) must operate through a sequence of only three intermediate outcomes. These efforts must either (1) reduce the likelihood that a woman will become pregnant; (2) reduce the likelihood that a pregnant woman will experience a serious complication of pregnancy or childbirth; or (3) improve the outcomes for women with complications. Several types of interventions are most likely to have substantial and immediate effects on maternal mortality, including family planning programs to prevent pregnancies, safe abortion services to reduce the incidence of complications, and improvements in labor and delivery services to increase the survival of women who do experience complications.

Family Planning Services↗
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BSI certification.

Explore the source record for details and available documents.

Biomedical Engineering↗
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Contraceptive knowledge and practices in Ilorin, Nigeria: 1983-88.

This report describes changes in knowledge and use of contraceptives in Ilorin, Nigeria between 1983 and 1988, a period marked both by dramatic changes in Nigeria's economic climate, as a result of the decline in the value of oil exports, and by considerable increases in public programs aimed at promoting the use of family planning and reducing fertility. The report is based on the analysis of two surveys of married women aged 15-35 years who lived in the city of Ilorin. By 1988, knowledge of modern methods of contraception had become virtually universal in Ilorin, even among women with no education and among those living in the poorest areas of the city. Current use of contraceptives had also increased considerably since 1983, reaching prevalence rates of 15 percent among women with primary education, 20 percent among those with secondary education, and 40 percent among those with postsecondary education. Each of these groups of women experienced at least a doubling of contraceptive prevalence between 1983 and 1988. Although use among uneducated women was still low in absolute terms (prevalence of 4.5 percent), these women also experienced a substantial relative increase in use.

Adolescent↗