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Biomedical subjects

J J Grady

Publications and source records attributed to J J Grady.

33 records · Page 2Linked to original sources
PubMed1998

Trail Making Test: issues in normative data selection.

The Trail Making Test (TMT) is one of the most frequently administered neuropsychological instruments, having been used in the evaluation of cognitive dysfunction for over 50 years. Despite the measure's extensive clinical use and proliferation of research, no comprehensive review of the adult TMT normative literature is available. This report examines the available TMT normative reports and provides a summary of the sample characteristics. Significant variability between studies precludes the use of metanorms. Clinically, these findings indicate that biased results may be obtained if the most appropriate normative data set is not used and underscore the importance of identifying the normative comparison group that approximates the relevant patient characteristics. To assist the clinician, selected normative reports (based on certain exclusionary parameters) have been compiled for three nonclinical comparison groups: (a) an adolescent and young adult group (ages 15-24), (b) an adult group (ages 20-54), and (c) an older adult group (ages 55-85). Results are discussed in terms of the influence of moderator variables on TMT performance and other factors, such as procedural differences in administration, that may account for the significant variability between normative samples.

Journal Article↗
PubMed1997

Efficacy of hypertonic 7.5% saline and 6% dextran-70 in treating trauma: a meta-analysis of controlled clinical studies.

BACKGROUND: Individual trials of small-volume resuscitation of 7.5% NaCl (HS) with and without 6% dextran 70 (HSD) for the treatment of trauma have failed to provide convincing evidence of efficacy. We performed a meta-analysis to evaluate the effects of HS and HSD on survival until discharge or for 30 days. We identified eight double-blinded, randomized controlled trials of HSD and six trials of HS. In all cases, administration of 250 ml of HSD or HS was compared with a control group administration of 250 ml of isotonic crystalloid for the treatment of hypotension either in the field or at admission to the emergency department. METHODS: A fixed-effects meta-analysis was performed with the Mantel-Haenszel method of combining results from multiple studies. RESULTS: Overall, HS was not effective in improving survival with a weighted mean difference in survival of the HS group versus the isotonic control group equal to 0.6%. The results with HSD were more positive, with an increase in survival in seven of eight trials. The mean difference in survival rates favoring HSD (n = 615) over controls (n = 618) was 3.5% (p = 0.14, two-tailed; p = 0.07, one-tailed). The odds ratio was estimated to be 1.20 in favor of HSD with a 95% confidence interval of 0.94 to 1.57. CONCLUSIONS: The meta-analysis of the available data shows that HS is not different from the standard of care and that HSD may be superior.

Controlled Clinical Trials as Topic↗
PubMed1997

Individual patient cohort analysis of the efficacy of hypertonic saline/dextran in patients with traumatic brain injury and hypotension.

BACKGROUND: Resuscitation with hypertonic saline/dextran (HSD) has been suggested to be efficacious in patients who have traumatic brain injury and are hypotensive. We undertook a cohort analysis of individual patient data from previous prospective randomized double-blinded trials to evaluate improvements in survival at 24 hours and discharge after initial treatment with HSD in patients who had traumatic brain injury (head region Abbreviated Injury Score > or = 4) and hypotension (systolic blood pressure < or = 90 mm Hg). METHODS: All variables and end points were defined before initiation of data handling. Investigators were blind as to the treatment. Case report forms were received from six studies. Of these, 223 patients met the inclusion for traumatic brain injury. Comparisons between HSD and standard of care were made using stratified analysis and logistic regression to assess efficacy, confounding, and interaction. Potential confounding variables of pre-fluid treatment, Glasgow Coma Scale score (3-8 vs. 9-15), injury type, and systolic blood pressure can be considered a priori factors that were known before randomization. Effects of the various trials was also considered. RESULTS: Treatment with HSD resulted in a survival until discharge of 37.9% (39 of 103) compared with 26.9% (32 of 119) with standard of care (p = 0.080). Using logistic regression, adjusting for trial and potential confounding variables, the treatment effect can be summarized by the odds ratio of 2.12 (p = 0.048) for survival until discharge. CONCLUSIONS: Patients who have traumatic brain injuries in the presence of hypotension and receive HSD are about twice as likely to survive as those who receive standard of care.

Abbreviated Injury Scale↗
PubMed1996

Altered kinetics and extent of urinary daidzein and genistein excretion in women during chronic soya exposure.

Soybean consumption may be protective for breast cancer, possibly due in part to the presence of the isoflavones daidzein and genistein, which are weakly estrogenic. The metabolism and disposition of these phytoestrogens during chronic soya exposure were studied on a metabolic unit. Six healthy 22- to 29-year-old women consumed an unrestricted hospital diet for most of the study and ingested 12 oz of soymilk with each meal for one month. At two-week intervals, excretion of isoflavones in urine was studied, during which time the subjects consumed a constant basal diet for three to four days, ingested the full daily 36-oz portion of soymilk within 30 minutes each day for one to two days, and collected urine continuously. Urinary recovery of genistein [initially 23.9 +/- 17.3% (SD) of ingested genistin + genistein], daidzein (initially 66.2 +/- 23.5% of ingested daidzin + daidzein), and equol (initially 28% of the ingested precursors daidzin + daidzein in 1 subject and < 1% in 5 subjects) decreased progressively over four weeks of daily soya ingestion by 42% for genistein (p < 0.05) and 31% for daidzein (p < 0.01) but increased by 3- to 100-fold for equol (4 subjects, p < 0.05). Total amounts excreted and peak levels were similarly affected. The absorption half-lives (t 1/2) for genistein and daidzein were initially 2.7 +/- 0.8 and 1.6 +/- 0.5 hours, respectively, and during four weeks of soymilk ingestion decreased to 2.0 +/- 0.6 (p = 0.04) and 1.4 +/- 0.2 hours (p = 0.06), respectively, suggesting more rapid absorption. The appearance t 1/2 of equol can be estimated for only one subject initially (2.9 hrs), but during four weeks of soya ingestion it could be estimated for three more subjects (4.7 +/- 2.3 hrs). The excretion t 1/2 values for genistein and daidzein were initially 6.7 +/- 0.8 and 4.4 +/- 0.7 hours, respectively, and during four weeks of soymilk ingestion decreased to 4.2 +/- 1.2 (p = 0.005) and 3.2 +/- 1.1 hours (p = 0.005), respectively, suggesting more rapid excretion. For equol, the excretion t 1/2 was initially 9.1 hours (1 subject), and after two and four weeks of soymilk ingestion it was 13.4 +/- 9.7 and 5.5 +/- 1.6 hours (4 subjects, p = 0.046, 2 wks vs. 4 wks), respectively. These results indicate that metabolism and disposition of ingested isoflavones are altered during chronic soya ingestion in women, perhaps from increased metabolic degradation to formation of nonisoflavone metabolites. Increased production of the longer- and stronger-acting estrogenic equol in some women during chronic soymilk ingestion may alter the estrogenic potency of dietary soya isoflavones.

Absorption↗
PubMed1996

Effects of soya consumption for one month on steroid hormones in premenopausal women: implications for breast cancer risk reduction.

Soybean consumption is associated with reduced rates of breast, prostate, and colon cancer, which is possibly related to the presence of isoflavones that are weakly estrogenic and anticarcinogenic. We examined the effects of soya consumption on circulating steroid hormones in six healthy females 22-29 years of age. Starting within 6 days after the onset of menses, the subjects ingested a 12-oz portion of soymilk with each of three meals daily for 1 month on a metabolic unit. Daily isoflavone intakes were approximately 100 mg of daidzein (mostly as daidzin) and approximately 100 mg of genistein (mostly as genistin). Serum 17 beta-estradiol levels on cycle days 5-7, 12-14, and 20-22 decreased by 31% (P = 0.09), 81% (P = 0.03), and 49% (P = 0.02), respectively, during soya feeding. Decreases persisted for two or three menstrual cycles after withdrawal from soya feeding. The luteal phase progesterone levels decreased by 35% during soya feeding (P = 0.002). Dehydroepiandrosterone sulfate levels decreased progressively during soya feeding by 14-30% (P = 0.03). Menstrual cycle length was 28.3 +/- 1.9 days before soymilk feeding, increased to 31.8 +/- 5.1 days during the month of soymilk feeding (P = 0.06), remained increased at 32.7 +/- 8.4 days (P = 0.11) at one cycle after termination of soymilk feeding, and returned to pre-soya diet levels five to six cycles later. These results suggest that consumption of soya diets containing phytoestrogens may reduce circulating ovarian steroids and adrenal androgens and increase menstrual cycle length. Such effects may account at least in part for the decreased risk of breast cancer that has been associated with legume consumption.

Adult↗
PubMed1995

Model selection techniques for the covariance matrix for incomplete longitudinal data.

In longitudinal studies with incomplete data, where the number of time points can become numerous, it is often advantageous to model the covariance matrix. We describe several covariance models (for example, mixed models, compound symmetry, AR(1)-type models, and combination models) that offer parsimonious alternatives to unstructured sigma. We evaluate each covariance model with longitudinal data concerning cholesterol as the repeated outcome measure. We discuss strategies for deciding the 'best' model and show a graphical technique for judging goodness-of-fit of covariance models.

Cholesterol↗
PubMed1995

Altered time course of urinary daidzein and genistein excretion during chronic soya diet in healthy male subjects.

Soybean consumption is associated with reduced rates of prostate and other cancers, possibly due in part to the presence of isoflavones. The metabolism and disposition of these soya-derived phytoestrogens after chronic soya exposure were studied on a metabolic unit in six healthy males (21-35 yrs of age) who consumed an unrestricted hospital diet and a 12-oz portion of soymilk with each meal for one month. The daily isoflavone intake was about 100 mg of daidzein (mostly as diadzin) and about 100 of mg of genistein (mostly as genistin). At two-week intervals, excretion of isoflavones in urine was studied, during which time the subjects consumed a constant basal diet for three to four days, ingested the full daily 36-oz portion of soymilk within 30 minutes each day for one to two days, and collected urine continuously. The urinary recovery of ingested diadzin plus daidzein (46.9 +/- 15.2%, mean +/- SD) and genistin plus genistein (14.6 +/- 9.2%) did not change with prolonged soya ingestion. The absorption half-lives (t1/2) for daidzein and genistein and the appearance t1/2 for equol (1 subject) were initially 1.5 +/- 0.4, 1.9 +/- 0.6, and 2.2 hours, respectively, and 2.5 +/- 1.1 (p = 0.06 compared with baseline) 1.4 +/- 0.9 (p = 0.03) compared with baseline), and 4.2 hours, respectively, during one month of soymilk ingestion. The excretion t1/2 for daidzein, genistein, and equol were initially 2.9 +/- 0.5, 3.8 +/- 0.7, and 5.2 hours, respectively, and 3.9 +/- 1.2 (p - 0.03), 5.5 +/- 1.6 (p = 0.02), and 9.7 hours, respectively, during one month of soymilk ingestion. These results indicate that chronic soya exposure did not induce significant changes in the metabolic pathways of isoflavones but altered the time courses of daidzein and genistein excretion. Thus chronic exposure to soya might prolong the tissue exposure to the presumed biologically active free and unconjugated forms of these isoflavones and thereby enhance their oncoprotective effects.

Absorption↗
PubMed1994

The effects of carrier gas composition on the performance of the Tec 6 desflurane vaporizer.

The new Tec 6 desflurane vaporizer is an electrically heated, pressurized, electromechanically coupled dual-circuit blender. We hypothesized that carrier gas viscosity should affect the electromechanical coupling of the fresh gas and vapor circuits, and that desflurane output should vary with different carrier gases. In the first portion of the study, the performance of eight vaporizers was evaluated using a constant dial setting of 10% desflurane with four different carrier gases and three different fresh gas flow rates. In the second portion of the study, the carrier gas flow rate was maintained at 1, 5, or 10 L/min, and vaporizer output was analyzed at all integer dial settings from 1% to 18%. Vaporizer output was highest when oxygen was the carrier gas and lowest when nitrous oxide was the carrier gas. This effect was accentuated at low fresh gas flow rates and correlated with carrier gas viscosity. At a flow rate of 1.0 L/min with a constant dial setting of 10%, the averaged output from vaporizers was 10.3 +/- 0.66, 9.4 +/- 0.58, 8.7 +/- 0.52, and 8.1 +/- 0.44 vol% for 100% oxygen, air, 30% oxygen plus 70% nitrous oxide, and 100% nitrous oxide, respectively. With 100% nitrous oxide as the carrier gas at a flow rate of 1.0 L/min, the vaporizer delivered 2 vol% less than the dial setting at dial settings in excess of 12%. Differences between the analyzed concentration and the dial setting were most pronounced with high concentrations of nitrous oxide at low fresh gas flow rates.

Anesthetics↗
PubMed1993

Torque and pullout analysis of six currently available self-tapping and "emergency" screws.

Insertional torque (IT), stripping torque (ST), and uniaxial pullout tests were performed to evaluate the effectiveness of six screw systems (Wurzburg, Techmedica, Synthes, Timesh, Steinhouser, Luhr) in thin porcine rib. The Timesh 2.2-mm self-tapping screw produced the largest insertional and stripping torque of all systems tested as well as the largest difference between the insertional and stripping torque. The Timesh emergency screw also had the largest insertional and stripping torque as well as the largest difference between the insertional and stripping torque. In pullout tests, the Timesh screw was found to be the most retentive. The overall data indicated that the ideal self-tapping screw should have the largest difference possible between drill size and external diameter, a channel, and at least three self-tapping threads for maximum retention.

Animals↗
PubMed1993

Comparison between uniaxial pull-out tests and torque measurement of 2.0-mm self-tapping screws.

This study investigates the retentive capacity of 2.0-mm self-tapping screws in porcine rib utilizing axial pull-out tests as well as torque measurements of insertion and stripping. These techniques have been performed independently; this analysis assesses the association between pull-out and torque values. The Goodman-Kruskel correlation coefficient between pull-out and insertional torque is 0.13, while the correlation between pull-out and stripping torque is 0.21. Partial correlation indexes control the thickness of bone, a confounding factor. Nonparametric analysis of covariance showed no significant difference between insertion of screws and pull-out of the screws, but stripping versus pull-out test was significant. Given these findings, it appears that insertional torque may be used as an alternative technique for screw retention analysis. Because insertional torque tests can be conducted in the operating room, results of clinical studies can be compared to laboratory analyses.

Analysis of Variance↗
PubMed1993

Evaluation of emergency screws in nonstripped pilot holes in bone.

Clinicians continue to search for a rigid internal fixation system that will remain stable in thin bone, such as that found in the lateral walls of the maxilla. Insertion of a large-diameter screw in a pilot hole has been suggested to improve screw retention. This study evaluates insertional and stripping torque of six emergency screw systems placed in nonstripped pilot holes of porcine rib (thickness < or = 2 mm). The Timesh and Synthes emergency screws did not properly fit into the nonstripped pilot holes. The Techmedica emergency screw was the most retentive. The Luhr, Wurzburg, and Steinhouser emergency screws were less retentive. The Techmedica emergency screw had the greatest stripping torque in nonstripped pilot holes, but it was not significantly greater when compared to the stripping torque of identical screws placed in 2.0-mm stripped holes. The Luhr, Wurzburg, and Steinhouser emergency screws placed in 1.5-mm pilot holes had significantly less stripping torque when compared to identical screws placed in 2.0-mm stripped holes. It appears the Luhr, Wurzberg, and Steinhouser 2.0-mm self-tapping screws have a greater stripping torque than the corresponding emergency screw when placed in 1.5-mm pilot holes.

Analysis of Variance↗
PubMed1992

Accuracy of quantification of mandibular condyle displacement in digitally subtracted linear tomograms.

Using a TMJ skeletal phantom, we assessed validity and reliability of digitally subtracted linear tomographic images to quantify condylar position changes. Horizontally corrected frontal and lateral tomographic images were made with the condyle in a 'centred' position and displaced by 1, 2 and 3 mm increments in two of three directions (inferior, and posterior, or lateral). Film images were sequentially subtracted and then randomized so that observers were blinded to the amount and direction of condylar movement. Averages of three measurements of the dark bands representing condylar shifts were made using a digitizing tablet. The study utilized a nested design where the series of film images was subtracted twice and each subtraction was read twice by two examiners. We repeated the study with a second series of films treated in an identical manner. Average differences from expected values were similar for frontal and lateral techniques and all directions and increments of displacement. Typical average difference for any increment was less than 0.1 mm. Standard deviations in measures were similar across techniques and increments and were typically less than 0.1 mm. Significant variation in the absolute value of differences between measured and expected values by direction of condylar displacement was attributed to greater accuracy of registration on the vertical axis for frontal images. A significant source of variation in the study design element 'film set' was attributed to errors in repositioning the phantom.(ABSTRACT TRUNCATED AT 250 WORDS)

Analysis of Variance↗
PubMed1991

Digitally subtracted linear tomograms: three techniques for measuring condylar displacement.

Using digital subtraction enhancement, we compared the accuracy of three tomographic technique variations for quantifying small changes of condylar position. A phantom made of skeletal material and an adjustable mechanical stage provided 0.1 mm positioning accuracy of the condylar segment. Linear tomographic images were made with the condyle in a centered position and at each of three 1 mm increments of displacement in two of three directions (inferior, and posterior or lateral). Variations for frontal views included arbitrary (+20 degrees) and individualized (+10 degrees) horizontal correction of the condylar axis. Variations for lateral views included the arbitrary and individualized correction and a fully corrected vertical (+5 degrees) and horizontal (+10 degrees) adjustment. Blinded observers made repeated measurements on randomized subtraction images with a digitizing tablet. Film images were subtracted twice, and each subtraction was read twice by two examiners. The study was repeated with a second series of films treated in an identical manner. Mean values for measurements, standard deviations, and absolute values of differences between measured and expected values were calculated for each subtraction. Analysis of variance identified statistically significant sources of variation in repositioning the phantom and producing exact displacements of the condyle. Average absolute value of differences from expected values were similar for the three techniques and for frontal and lateral orientations and increments of displacement. Typical absolute value of difference for any technique was 0.2 mm for posterior, 0.2 mm for lateral, and 0.1 mm for inferior displacements. Significantly greater accuracy of inferior displacement measures was attributed to greater accuracy of registration of the fossa in its cranio-caudal dimension.(ABSTRACT TRUNCATED AT 250 WORDS)

Analysis of Variance↗
PubMed1990

Accuracy of student self-evaluations of dental sealants.

The purpose of this study was to (1) assess the accuracy of student self-evaluations of dental sealants through comparisons with faculty evaluations, and (2) determine if a difference in accuracy exists between dental and dental hygiene students. Dental (n = 17) and dental hygiene (n = 13) students from the University of North Carolina School of Dentistry at Chapel Hill placed and evaluated a total of 127 dental sealants on 29 patients in the undergraduate patient care system. Each student evaluated the placed sealant using criteria for the characteristics: area covered, quantity, porosity, and retention. The student self-evaluation was followed by an evaluation performed by two faculty examiners using the same criterion-referenced evaluation. The average of the two faculty evaluations was compared with the student's self-evaluation for analyses. Results indicated student scores were consistently higher than those given by the faculty. Additionally, dental and dental hygiene student scores correlated to about the same degree with the faculty average score.

Child↗