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Biomedical subjects

S Gallagher

Publications and source records attributed to S Gallagher.

At least 19 recordsLinked to original sources
PubMed2004

Comparison of myocardial gated single photon emission computerised tomography, planar radionuclide ventriculography and echocardiography in evaluating left ventricular ejection fraction, wall thickening and wall motion.

Left ventricular ejection fraction (LVEF) and wall thickening are fundamental aspects of cardiac function. Recently, gated single photon emission computerised tomography (GSPECT) and anatomical M-mode echocardiography are new techniques, which have been introduced for the evaluation of left ventricular wall thickening and ejection fraction. These, however, have not been evaluated against established techniques, including equilibrium radionuclide ventriculography (ERNV), which remains the current gold standard for the evaluation of LVEF. We examined the concordance between LVEF, wall motion and wall thickening scores derived from GSPECT, echocardiography and ERNV, in a group of 16 patients with suspected ischaemic heart disease. Estimated ejection fraction correlated better between ERNV and gated SPECT (R2 = 0.93) than between echocardiography and either gated SPECT (R2 = 0.62) or ERNV (R2 = 0.71). There was poor correlation between gated SPECT and anatomical M-mode echocardiography in the assessment of wall thickening (83/150, 56%; kappa= 0.31, p < 0.05) and similar correlation (100/150, 66%; kappa = 0.29, p < 0.01) for wall motion analysis. In conclusion, estimations of ejection fraction by all the three studied modalities agreed to a degree sufficient for routine clinical practice. However, estimates of wall thickening from echocardiography cannot be used interchangeably with those derived from gated myocardial perfusion SPECT.

Adult↗
PubMed2001

Identification of a null allele of CYP2C9 in an African-American exhibiting toxicity to phenytoin.

Cytochrome P450 (CYP) 2C9 is the principal enzyme responsible for the metabolism of numerous clinically important drugs. Two polymorphic alleles CYP2C9*2 and CYP2C9*3 have been documented which affect the metabolism and clinical toxicity of drugs such as phenytoin, warfarin, glipizide, and tolbutamide. The present study reports the first example of a null polymorphism in CYP2C9. This mutation dramatically affects the half-life and clinical toxicity of phenytoin. The study subject was a female African-American presented to the emergency department with phenytoin toxicity evidenced by mental confusion, slurred speech, memory loss and the inability to stand. She exhibited extremely poor clearance of phenytoin with an elimination half-life of approximately 13 days. Genotyping studies demonstrated that the patient did not possess any known variant CYP2C9 alleles. Phenytoin is metabolized to a minor extent by the polymorphic CYP2C19, but this individual did not possess any variant CYP2C19 alleles. Sequencing studies revealed that the individual was homozygous for a new CYP2C9 allele (CYP2C9*6) with the deletion of an adenine at base pair 818 of the cDNA. The clearance of phenytoin in this individual is estimated to be approximately 17% of that observed in normal patients. The frequency of this allele was 0.6% (95% confidence limits of 0.1 to 3.5%) in 79 African-Americans and 0% (95% confidence limits of 0 to 1.1%) in 172 Caucasians. The study also demonstrates the severe clinical consequences to patients with a null mutation in CYP2C9 after treatment with normal doses of phenytoin.

Administration, Oral↗
PubMed2001

Effects of response disparity on stimulus and reinforcer control in human detection tasks.

In two detection experiments, university students reported whether the second of two sequentially presented tones was longer or shorter than the first by responding to stimuli presented on a touch screen. Stimulus disparity and response disparity were manipulated to compare their effects on measures of discrimination and response bias when the reinforcement ratio for correct responses was asymmetric. Choice stimuli consisted of squares filled with different pixel densities. Response disparity was manipulated by varying the difference in density between the two choice stimuli. In both experiments, decreasing stimulus disparity reduced discrimination but had no consistent effect on bias. Decreasing response disparity also reduced discrimination in both experiments, and often reduced estimates of bias. The effects of response disparity on bias were most clear in Experiment 2, in which a greater overall level of response disparity was arranged. The data show that, like corresponding research with pigeons, detection performance of human subjects can be conceptualized as discriminated operants.

Adolescent↗
PubMed2001

HypnoBirthing.

Explore the source record for details and available documents.

Delivery, Obstetric↗
PubMed1998

Hand-mouth coordination, congenital absence of limb, and evidence for innate body schemas.

Studies of phantom limb in cases of congenital (aplasic) absence of limb have provided inadequate evidence concerning the innate neurological substrate responsible for the phantom. In this study we review evidence from ultrasonic and behavioral studies of hand-mouth coordination in utero and in early infancy, neurobiological studies in primates, and studies of neural reorganization following amputation. We suggest two complementary hypotheses to explain aplasic phantoms. First, aplasic phantoms are based on the existence of specific neural circuitry associated with innate motor schemas, such as the neural matrix responsible for early hand-mouth coordination. Second, aplasic phantoms are modified by mechanisms that involve a reorganization of neural representations of the missing limb within a complex network involving both cortical and subcortical structures.

Adolescent↗
PubMed1998

Quality care for cardiology patients.

To evaluate outcome measures in a cardiology unit, patient satisfaction was measured. Patients consistently related problems in two areas: pain management and the waiting period before their procedure. After a major system change, patient satisfaction increased 16% and 29% respectively.

Heart Diseases↗
PubMed1997

Trunk extension strength and muscle activity in standing and kneeling postures.

STUDY DESIGN: A split-plot experimental design was used to evaluate the influence of posture, trunk angle, and rotational velocity on peak torque output and myoelectric activity during maximal trunk extension maneuvers. OBJECTIVES: To determine whether the kneeling posture alters extension torque capabilities in isometric and isokinetic exercises as compared with standing. Also, to ascertain whether recruitment of trunk muscles is modified by such a postural change. SUMMARY OF BACKGROUND DATA: Factors such as workplace geometry may force workers to adopt awkward or unusual postures in the performance of manual tasks. An understanding of the limitations placed on strength in unconventional working postures is crucial to the proper design of jobs. METHODS: Twenty-one healthy male subjects (mean age = 36 years +/- 7 SD) performed 12 trunk extension exertions in standing and kneeling postures. Isometric tests were performed at 22.5 degrees, 45 degrees, and 67.5 degrees of trunk flexion. Isokinetic tests were done at three velocities: 30 degrees/sec, 60 degrees/sec, and 90 degrees/sec. Electromyographic data were collected from eight trunk muscles to assess muscle recruitment under each condition. A priori orthogonal contrasts were specified for analysis of both torque and electromyographic data. RESULTS: The kneeling posture was associated with a 15% decrease in peak torque output when contrasted with standing: however, no concomitant change in trunk muscle activity was evident. Trunk hyperflexion (isometric tests) and increasing rotational velocity (isokinetic tests) were associated with reduced torque in both postures. Trunk muscle activity was primarily affected by changes in trunk angle and velocity of contraction. CONCLUSIONS: A reduced extensor capability exists in the kneeling posture, despite equivalent trunk muscle activity. The similar activation patterns in both postures suggest that the strength deficit does not result from alterations in trunk muscle function. Rather, it may be the consequence of a reduced capability to rotate the pelvis in the kneeling posture, due to a disruption of the biomechanical linkage of the leg structures.

Adult↗
PubMed1997

Surviving redesign: basic concepts of patient-focused care and their application to WOC nursing.

The concept of patient-focused care continues to gain popularity in health care delivery throughout the United States. In an effort to compete more effectively in today's market, health care institutions have adopted strategies from industry to control rising costs. WOC nurses in every practice setting are feeling the effects of one such strategy, patient-focused care. The purpose of this article is to describe basic concepts of patient-focused care, a redesign technique that was born out of continuous quality improvement, and to present strategies tailored to strengthen WOC nursing practice in this changing and challenging environment.

Case Management↗
PubMed1997

Measurement of nucleic acid concentrations using the DyNA Quant and the GeneQuant.

Molecular biology is now a routine tool in almost all biological research fields. With the exponential growth in the number of molecular biological techniques, there is a recognizable need for sensitive, accurate and precise quantitation of nucleic acids. We present here two complementary instruments designed for the quantitation of nucleic acids, the GeneQuant II and the DyNA Quant 200 Fluorometer. The GeneQuant II can rapidly determine the UV absorbance of a solution and display the calculated DNA, RNA or protein concentration. In addition, the GeneQuant can display calculated melting temperatures for a given DNA oligonucleotide base sequence, a useful feature for primer design. The DyNA Quant 200 quantitates DNA on the basis of the fluorescent Hoechst 33258 dye/double-stranded (ds)DNA assay. Upon binding to dsDNA, the spectral properties of the dye change such that it becomes highly fluorescent at 460 nm when excited at 365 nm. The assay has proven to be a specific and sensitive alternative method for DNA quantitation, particularly for unpurified DNA samples. Together, the GeneQuant II and the DyNA Quant 200 are a cost-effective and convenient solution to the routine protein and nucleic acid quantification needs of the molecular biologist.

Bisbenzimidazole↗
PubMed1996

Coronary restenosis.

Return of angina within 6 months of a catheter-based treatment of coronary artery disease usually reflects restenosis due to an overly aggressive local healing response to the procedure-related arterial injury. The restenotic lesion should be treated aggressively. Patients with preexisting diabetes mellitus, renal failure requiring hemodialysis, and left anterior descending artery lesions should be considered to be at exceedingly high risk for clinically significant restenosis. Exercise testing is indicated for all patients who experience a return of their angina within 6 months of an interventional procedure. Nurse practitioners in the primary care setting may be the first clinicians to hear of the return of angina. Patients should always be reassured that repeat intervention is almost always possible and is generally effective in providing long-term relief. New devices (in particular the Palmaz-Schatz stent) may help reduce the likelihood of restenosis, to the extent that they provide a large acute post-treatment lumen diameter that is more tolerant of intimal hyperplasia without producing significant narrowing. Until adjunctive drug therapy is found that effectively reduces the local tissue response to interventional therapy, all clinicians involved in caring for patients following such procedures will need to be vigilant and knowledgeable about recognizing and treating restenosis.

Angioplasty, Balloon, Coronary↗
PubMed1995

Marketing a hospital-based specialty program.

The 1980s were a time of growth and opportunity for hospital-based specialty programs. ET nurses developed a variety of highly valued clinics and services. Because of current trends toward downsizing, otherwise strong programs and services are undergoing unusual scrutiny. The purpose of this article is to offer the ET nurse ideas for strengthening hospital-based specialty programs through a marketing approach.

Enterostomy↗
PubMed1994

Retroperitoneal hematoma after cardiac catheterization: prevalence, risk factors, and optimal management.

PURPOSE: Retroperitoneal hematoma is an unusual, but potentially serious, complication after cardiac catheterization. The predisposing factors, typical presentation, and clinical course of this iatrogenic complication are identified, and the role of surgery in its treatment is defined. METHODS: A retrospective review of 9585 femoral artery catheterizations over a 5-year period allowed identification and evaluation of all patients with retroperitoneal hemorrhage. RESULTS: Retroperitoneal hematoma developed in 45 patients (overall prevalence 0.5%), with the highest frequency after coronary artery stenting (3%). In the group of patients who underwent coronary artery stenting, statistically significant predictors of this complication included protocol for sheath removal, female sex, nadir platelet count, and excessive anticoagulation. Signs and symptoms included suprainguinal tenderness and fullness in 100%, severe back and lower quadrant pain in 64%, and femoral neuropathy in 36%. Most patients were treated successfully with transfusion alone. Seven patients (16%) required operation; in four, hypotension unresponsive to volume resuscitation developed early after catheterization; and, in three, a progressive fall in hematocrit level led to surgery 24 to 72 hours after catheterization. CONCLUSIONS: Retroperitoneal hematoma after cardiac catheterization can usually be treated by transfusion alone. A small subset of patients who have development of hypotension unresponsive to volume resuscitation require urgent operation.

Aged↗
PubMed1994

Dynamic biomechanical modelling of symmetric and asymmetric lifting tasks in restricted postures.

This article describes investigations of dynamic biomechanical stresses associated with lifting in stooping and kneeling postures. Twelve subjects volunteered to participate in two lifting experiments each having two levels of posture (stooped or kneeling), two levels of lifting height (350 or 700 mm), and three levels of weight (15, 20, or 25 kg). One study examined sagitally symmetric lifting, the other examined an asymmetric task. In each study, subjects lifted and lowered a box every 10 s for a period of 2 min in each treatment combination. Electromyography (EMG) of eight trunk muscles was collected during a specified lift. The EMG data, normalized to maximum extension and flexion exertions in each posture, was used to predict compression and shear forces at the L3 level of the lumbar spine. A comparison of symmetric and asymmetric lifting indicated that the average lumbar compression was greater in sagittal plane tasks; however, both anterior-posterior and lateral shear forces acting on the lumbar spine were increased with asymmetric lifts. Analysis of muscle recruitment indicated that the demands of lifting asymmetrically are shifted to ancillary muscles possessing smaller cross-sectional areas, which may be at greater risk of injury during manual materials handling (MMH) tasks. Model estimates indicated increased compression when kneeling, but increased shear forces when stooping. Increasing box weight and lifting height both significantly increased compressive and shear loading on the lumbar spine. A multivariate analysis of variance (MANOVA) indicated complex muscle recruitment schemes--each treatment combination elicited a unique pattern of muscle recruitment. The results of this investigation will help to evaluate safe loads for lifting in these restricted postures.

Adult↗