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Biomedical subjects

J M Walsh

Publications and source records attributed to J M Walsh.

At least 19 recordsLinked to original sources
PubMed2003

The effect of investment material and ceramming regime on the surface roughness of two castable glass-ceramic materials.

OBJECTIVE: To assess the surface roughness (R(a)) of two castable glass-ceramic materials, cast using four different investment materials and employing different ceramming regimes. METHODS: Forty discs, each 12 mm diameter and 2 mm thick were produced from two castable glass-ceramic materials, one a glass ionomer derivative based on 1.5SiO(2)-1Al(2)O(3)-0.53P(2)O(5)-1CaO-0.67CaF(2) (LG112), the other a fluorcanasite material based on 0.60SiO(2)-0.05K(2)O-0.10Na(2)O-0.15CaO-0.10CaF(2) (SG3). The discs were made using four dental investments, two gypsum-bonded (Whip-Mix Cristobalite (WMC), Degussa California (DC)) and two phosphate-bonded (Fujivest Super (FS), Techceram Glass (TG)). A Ni-Cr metal/ceramic alloy (Wiron 99) was also used as a control. Each investment was used to produce 10 discs for each glass-ceramic material, five left in the as-cast, glass state, the other five cerammed. Ceramming was carried out either within the investment mold or after de-vesting from the investment mold. The discs had their surface roughness values measured using a stylus, surface contact measuring instrument. RESULTS: For the Ni-Cr alloy the phosphate-bonded investments produced discs significantly smoother than those produced by the two gypsum-bonded investments (p<0.05). The FS investment produced the smoothest discs (p<0.05), but there was no significant difference between the discs produced by the two gypsum-bonded investments (p>0.05). For the SG3 material no significant differences were seen between the as-cast glass and cerammed discs (p>0.05), with the WMC investment producing the smoothest discs (p<0.05), and the TG investment the roughest (p<0.05). The LG112 material showed a significant difference between glass and cerammed discs for the gypsum-bonded investments (p<0.05) but not when using phosphate-bonded investments (p>0.05). With LG112 the WMC investment produced smoother discs than the DC and TG investments (p<0.05). The DC investment produced rougher discs than the two phosphate-bonded investments (p<0.05). SIGNIFICANCE: The selection of investment material can have a significant effect on the as-cast surface finish of castable glass-ceramic materials. A gypsum-bonded investment material gave smoother surface finishes compared to phosphate-bonded investments. The ceramming process significantly increases surface roughness.

Analysis of Variance↗
PubMed2002

Comparing first and subsequent suprapubic catheter change: complications and costs.

Urologic and continence nursing advanced significantly during the 1990s. Today's health care environment emphasizes careful rationalizing of hospital-based resources. This trend is more or less responsible for the demise of medically managed suprapubic catheter (SPC) change. The results of this study indicate that first change of SPC, performed in the patient's home or outpatient clinic by appropriately skilled registered nurses, is a cost-effective practice with no increased risk of complication to the patient.

Cost-Benefit Analysis↗
PubMed2001

The cost of on-site versus off-site workplace urinalysis testing for illicit drug use.

Workplace drug testing has become standard business practice in America. With increasing costs, however, many corporations look for more cost-effective testing alternatives. The study compared the cost of two testing strategies: urinalysis at the work site versus testing that occurs elsewhere. Employees from seven company locations were tested for illicit drugs. Four sites conducted the initial screening test at the workplace and three sites performed testing off site. On-site testing was found to have significantly lower variable costs, and total costs were lower once a threshold of 27 employees tested was attained. On-site testing also provided immediate access to negative test results, thereby facilitating personnel decisions.

Contract Services↗
PubMed2001

Predictors of physical activity in community-dwelling elderly white women.

OBJECTIVE: To describe patterns of physical activity and to determine factors associated with engaging in regular exercise, especially walking, in elderly white women. DESIGN: Cross-sectional study of 9,442 independently living elderly white women aged 65 years and over participating in the Study of Osteoporotic Fractures. MEASUREMENTS AND MAIN RESULTS: We studied the association between lifestyle habits, social factors, health status and self-reported physical activity (assessed by modified Paffenbarger scale) during the past twelve months. Walking was the most common form of exercise: 4,837 (51%) women reported doing so a mean of 12 (SD = 10) blocks per day, 3.9 (SD = 2.9) times per week. Other common activities were gardening (35%), swimming (16%), and bicycling (13%). Less than a third of women reported engaging in medium- or high-intensity exercise in the past year. In a multivariate age-adjusted analysis, factors independently (P < .01) associated with walking for exercise included greater than high school education (52% vs 48%), history of physical activity for exercise at ages 30 years (51% vs 46%) and 50 years (51% vs 45%), and stronger social network (51% vs 47%). Women who were current smokers, obese, or depressed were less likely to take walks for exercise. Marital status, self-reported arthritis, current estrogen use, and a history of falls in the past year were not independently associated with taking walks for exercise. CONCLUSIONS: In this healthy cohort, walking for exercise is associated with other positive health behaviors. Given the mounting evidence about the health benefits of walking, and since many of these community dwelling women can and do walk for exercise, but rarely engage in other common prescribed physical activities, clinicians might best focus their efforts on encouraging walking.

Aged↗
PubMed2000

Testicular hormones modulate circadian rhythms of the diurnal rodent, Octodon degus.

Sex differences have been identified in a variety of circadian rhythms, including free-running rhythms, light-induced phase shifts, sleep patterns, hormonal fluctuations, and rates of reentrainment. In the precocial, diurnal rodent Octodon degus, sex differences have been found in length of free-running rhythm (tau), phase response curves, rates of reentrainment, and in the use of social cues to facilitate reentrainment. Although gonadal hormones primarily organize circadian rhythms during early development, adult gonadal hormones have activational properties on various aspects of circadian rhythms in a number of species examined. Gonadectomy of adult female O. degus did not influence tau, phase angle of entrainment, or activity patterns in previous experiments. The present experiment examined the role of gonadal hormones in adult male degus' circadian wheel-running rhythms. We predicted that male gonadal hormones would have an activational effect on some aspects of circadian rhythms, particularly those in which we see sex differences. Phase angles of entrainment, tau, length of the active period (alpha), maximum and mean activity levels, and activity amplitude were examined for intact and castrated males housed in LD 12:12. Responses to light pulses while housed in constant darkness (DD) were also compared. Castration had no significant effect on tau or light-induced phase shifts. However, castration significantly increased phase angle of entrainment and decreased activity levels. The data indicate that adult gonadal steroids are not responsible for the sex differences in endogenous circadian mechanisms of O. degus (tau, PRC), although they influence activity level and phase angle of entrainment. This is most likely due to masking properties of testosterone, similar to the activity-increasing effects of estrogen during estrus in O. degus females.

Animals↗
PubMed2000

Effect of furnace type and ceramming heat treatment conditions on the biaxial flexural strength of a canasite glass-ceramic.

OBJECTIVE: To assess the effect of different heat treatment conditions when using two different furnace types on the biaxial flexural strength (BFS) of a fluorcanasite castable glass-ceramic. METHODS: Two furnace types, one a programmable furnace (PF), the other a dental laboratory burnout furnace (DLF), were used with various ceramming times to determine their effect on the BFS of a fluorcanasite castable glass-ceramic. The glass-ceramic material was cast to produce discs of 12 mm diameter and 2 mm thickness using the lost wax casting process (n = 80). After casting, both furnace types were used to ceram the discs. Half the discs were not de-vested from the casting ring before ceramming but cerammed in situ (DLF) and half were de-vested before ceramming (PF). All the discs were given a nucleation heat treatment at 520 degrees C for 1 h and then cerammed at 860 degrees C using four heat soak times (0.5, 1, 2 and 3 h). The DLF furnace had a rate of climb of 13 degrees C/min and the PF furnace had a rate of climb of 5 degrees C/min to 520 degrees C and 3 degrees C/min to 860 degrees C. After ceramming the discs were de-vested and the BFS determined using a Lloyd 2000R tester. RESULTS: The maximum BFS values seen for both furnace types were almost identical (280 MPa), but were achieved at different heat soak times (1 h DLF, and 2 h PF). The only significant differences in BFS values for the two furnaces were between the 0.5 and 2 h heat soak times (p < or = 0.05). Individual differences were seen between results obtained from each furnace type/heat soak times evaluated (p < or = 0.05). SIGNIFICANCE: Already available dental laboratory burnout furnaces can be used to ceram fluorcanasite glass-ceramic castings to the same BFS values as more expensive and slower specialist programmable furnaces.

Analysis of Variance↗
PubMed2000

Detection, evaluation, and treatment of eating disorders the role of the primary care physician.

OBJECTIVE: To describe how primary care clinicians can detect an eating disorder and identify and manage the associated medical complications. DESIGN: A review of literature from 1994 to 1999 identified by a MEDLINE search on epidemiology, diagnosis, and therapy of eating disorders, including anorexia nervosa and bulimia nervosa. MEASUREMENTS AND MAIN RESULTS: Detection requires awareness of risk factors for, and symptoms and signs of, anorexia nervosa (e.g., participation in activities valuing thinness, family history of an eating disorder, amenorrhea, lanugo hair) and bulimia nervosa (e.g., unsuccessful attempts at weight loss, history of childhood sexual abuse, family history of depression, erosion of tooth enamel from vomiting, partoid gland swelling, and gastroesophageal reflux). Providers must also remain alert for disordered eating in female athletes (the female athlete triad) and disordered eating in diabetics. Treatment requires a multidisciplinary team including a primary care practitioner, nutritionist, and mental health professional. The role of the primary care practitioner is to help determine the need for hospitalization and to manage medical complications (e.g., arrhythmias, refeeding syndrome, osteoporosis, and electrolyte abnormalities such as hypokalemia). CONCLUSION: Primary care providers have an important role in detecting and managing eating disorders.

Anorexia Nervosa↗
PubMed2000

Lipid screening in women.

Evidence of the benefits of lowering cholesterol in various populations continues to grow, but questions persist about screening and treatment of lipid disorders in women. In this paper, we review the distinct features of the epidemiology of lipids and coronary heart disease in women and data from recent long-term treatment trials specific to women. Although data from primary prevention trials in women remain sparse, recent trials demonstrating benefits of cholesterol reduction across a broad range of cholesterol levels and cardiac risk in men and women bolster the conclusion that benefits may extend to asymptomatic women who are otherwise at high risk for coronary disease. Periodic lipid screening beginning in middle age will identify most women who are at high enough risk to merit drug therapy or more intensive individual lifestyle interventions. More detailed consideration of age, diabetes, blood pressure, specific lipid levels, or the ratio of total cholesterol to high-density lipoprotein cholesterol, and other risk factors can more accurately estimate individual risk of coronary heart disease and identify high-risk women most likely to benefit from lipid reduction. Advice about healthy diet, weight control, and physical activity can benefit all women, but authorities differ on the benefits of routine lipid screening in low-risk younger women.

Adult↗
PubMed1999

Exercise counseling by primary care physicians in the era of managed care.

BACKGROUND: Recommendations from the Centers for Disease Control and Prevention (CDC) and the American College of Sports Medicine (ACSM) advise all adults to accumulate at least 30 minutes of moderate intensity physical activity on most, if not all, days of the week, but many U.S. adults engage in no leisure-time physical activity. Since primary care providers can play an important role in exercise counseling and prescription, we wanted to assess the proportion of primary care physicians from four hospitals who asked about exercise habits, counseled about exercise, and prescribed exercise; and the factors that were associated with their counseling and prescription habits. DESIGN: Survey of 326 internists, family practitioners, and internal medicine and family practice residents. RESULTS: One hundred seventy-five physicians completed the questionnaire (54% response rate). Two thirds of physicians reported asking more than half of their patients about exercise, 43% counseled more than half of their patients about exercise, but only 14% prescribed exercise for more than half of their patients. Only 12% of physicians were familiar with the new ACSM recommendations. Physicians aged 35 and over were more likely than physicians less than 35 year old to ask about (82% versus 60%), counsel about (58% versus 37%), and prescribe (30% versus 8%) exercise. Family practitioners were more likely to ask about (85% versus 62%) and counsel about (59% versus 39%) exercise than internists. Physicians who felt they had adequate exercise knowledge were more likely to ask about (72% versus 49%) and counsel about (48% versus 29%) exercise than those who felt their knowledge was inadequate. Finally, physicians who felt that they were successful in changing behavior were more likely to ask about and counsel about exercise. The most important barriers to exercise counseling were not having enough time and needing more practice in effective counseling techniques. CONCLUSION: Many primary care physicians are not asking about, counseling about, or prescribing exercise for their patients. Since primary care physicians are in the best position to provide individualized exercise prescriptions for their patients, future research should focus on training physicians in effective counseling techniques that can be done as brief interventions.

Adult↗
PubMed1998

The effect of casting conditions on the biaxial flexural strength of glass-ceramic materials.

OBJECTIVE: To assess the effect of mould and glass casting temperatures on the biaxial flexural strength (BFS) of two different types of castable glass-ceramic, using existing laboratory equipment and techniques. METHODS: Two castable glass-ceramic materials were evaluated. One glass (LG3) is based on SiO2-Al2O3-P2O5-CaO-CaF2, and is similar in composition to glasses used in the manufacture of glass-ionomer cements. The other glass (SG3) is based on SiO2-K2O-Na2O-CaO-CaF2, and is a canasite-based material. Both materials were used to produce discs of 12 mm diameter and 2 mm thickness using the same lost-wax casting process as used for metal castings. Mould temperatures of between 500 degrees C and 1000 degrees C and glass casting temperatures of between 1100 degrees C and 1450 degrees C were evaluated. The cast discs were cerammed and the biaxial flexural strength determined with a Lloyd 2000 R tester. RESULTS: A significant difference was found for the BFS in the range of mould temperatures evaluated, with the optimum investment mould temperature being 590 degrees C for LG3 and 610 degrees C for SG3 (p = 0.0002 and p = 0.019, respectively). No significant differences were seen between any of the glass casting temperatures evaluated. SIGNIFICANCE: The mould temperature for castable glass-ceramic materials produced using the lost-wax casting process can have a significant effect on BFS. The optimum mould temperature may differ slightly depending on the type of material being used. The glass casting temperature of these materials does not appear to have a significant effect on BFS.

Analysis of Variance↗
PubMed1998

Evaluation of the accuracy of on-site multi-analyte drug testing devices in the determination of the prevalence of illicit drugs in drivers.

A principal goal of this research was to conduct a field evaluation of "on-site" multi-analyte drug testing devices to determine the most accurate, efficient, and cost-effective device available for the purpose of rapidly detecting drivers under the influence of drugs. Four on-site kits were selected and evaluated for accuracy and efficiency for the detection of tetrahydrocannabinol (THC), the cocaine metabolites (COC), and opiates (OPI). From 16 December 1995 to 17 March 1996, 303 voluntary urine specimens were collected by law enforcement officers from persons arrested for driving-under-the-influence (DUI). These specimens were tested using the four selected kits and aliquots of the specimens were sent to a DHHS certified lab for "gold standard" comparison testing by immunoassay and Gas Chromatography/Mass Spectrometry. On-site kit sensitivity ranged from 82.9% to 100% for THC, 82.5% to 100% for COC, and all were at 100% for OPI. Specificity, and positive and negative predictive values were also determined. Accuracy ranged from 94.0% to 98.3% for THC, 97.4% to 98.0% for COC, and 99.7% to 100% for OPI. All four kits were in very close agreement on prevalence: 15.5% to 15.8% for THC, all were at 13.2% for COC, and all were at 0.7% for OPI. For law enforcement purposes, sensitivity may be the most important indicator in these kits.

Automobile Driving↗
PubMed1998

Cervical cancer: developments in screening and evaluation of the abnormal Pap smear.

Of the more than 50 million Pap smears performed annually in the United States, about 5% of them are abnormal. Although the need for treatment of high-grade lesions is clear, the appropriate management of low-grade lesions remains controversial. New methods of screening for cervical cancer have become available, including testing for the human papilloma virus and improved methods of administering and evaluating the Pap smear. This review addresses new developments in cervical cancer screening and management strategies for when an abnormality is detected.

Epithelial Cells↗
PubMed1995

Treatment of hyperlipidemia in women.

OBJECTIVE: To assess the evidence that lipid lowering prevents coronary heart disease (CHD) events in women. DATA SOURCES: English-language literature assessing the effects of cholesterol lowering with dietary and/or drug interventions as primary or secondary prevention on CHD events in women. MAIN OUTCOME MEASURES: Coronary heart disease and total mortality were the primary outcomes assessed. Angiographic regression of coronary atherosclerosis was a secondary outcome. STUDY SELECTION, DATA EXTRACTION, AND DATA SYNTHESIS: All nine of the identified studies that met the criteria were included. Relative risks for CHD and total mortality were calculated from available data. Summary relative risks were calculated using meta-analytic techniques. CONCLUSIONS: There is no evidence from primary prevention trials that cholesterol lowering affects total mortality in healthy women, although the available data are limited. Limited evidence suggests that treatment of hypercholesterolemia in women with coronary disease may decrease CHD mortality. Future research should address the role of dietary and other nondrug treatment of hypercholesterolemia in women at high risk for CHD.

Adult↗
PubMed1995

Influence of isometric loading on biceps EMG dynamics as assessed by linear and nonlinear tools.

The summed electrical discharges generated by a contracting skeletal muscle constitute a dynamic system conveying electromyographic (EMG) information indicative of muscle physiological status. "Steady states" of activity can be achieved with light loads, but with heavy loads the dynamic system experiences continuous status transitions that culminate in task failure. The present study was designed to assess the applicability of two mathematical tools, one linear and the other nonlinear, in addressing the time course of EMG alterations under different loading challenges. Surface EMGs of the biceps brachii muscle were recorded from 14 healthy human volunteers during light and heavy loadings, and task failure occurred at varying times among the subjects. Digitized EMG signals were analyzed by linear spectral analysis (fast Fourier transform) and nonlinear recurrence-plot analysis. With light loading, computed variables from both analyses gave "quasi-steady-state" values over time, with recurrence-plot analysis having the higher variance. With heavy loading, the nonlinear variable (%determinism) increased sooner and exhibited larger changes from control values than decreases in the linear variable (spectral center frequency). Experimental results support the conclusion that both analyses can be combined to give a fuller assessment of the biceps EMG during light or heavy loading. Implications for the detection of muscular fatigue are discussed.

Adult↗
PubMed1995

Reduced transplant lung volumes after single lung transplantation for chronic obstructive pulmonary disease.

Single lung transplantation is now an extremely successful option for the treatment of end-stage chronic obstructive pulmonary disease (COPD). This procedure involves placing a normal sized lung in a hyperinflated hemithorax. Preliminary observations of these patients suggest that the transplanted lung volume is smaller than expected and often the native (COPD) lung increases in volume. The purpose of this investigation was to quantify the volume contributions of the transplant and native lung to the total lung capacity. In seven patients who underwent single lung transplant for end-stage COPD the transplant and native lung volumes were measured by computer-analyzed planimetry immediately after transplant and the following 6 mo post-transplant. The transplant lung volume was smaller than predicted immediately after transplant at only 33 +/- 5% (mean +/- SD) of predicted TLC. This did not change significantly over the next 6 mo. Native lung volume increased following transplant to 74 +/- 19% predicted TLC at 1 mo and 80 +/- 16% at 6 mo. Five of the seven patients subsequently underwent measurement of pleural pressures at TLC. The mean static pleural pressure at TLC was low at -16 +/- 5.1 cm H2O. In summary, following single lung transplantation for COPD the transplanted lung is significantly restricted. We conclude that the likely mechanism of this restriction is due to low transpulmonary pressure generation.

Female↗