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Biomedical subjects

D B Cook

Publications and source records attributed to D B Cook.

At least 19 recordsLinked to original sources
PubMed2001

Moderate-intensity muscle pain can be produced and sustained during cycle ergometry.

PURPOSE: The aim of this experiment was to determine whether moderate-intensity quadriceps muscle pain could be produced and sustained during cycle ergometry. METHODS: 12 women volunteers completed a peak cycle ergometry test during which quadriceps muscle pain-intensity ratings were obtained using a 0-10 scale. On a subsequent day, participants cycled for 20 min beginning at the power output associated with quadriceps muscle pain threshold during the peak test. Participants manipulated power output during the first 10 s of each minute to produce and sustain moderate-intensity quadriceps muscle pain. During the last 20 s of each minute, VO2, ratings of quadriceps muscle pain intensity, and ratings of perceived exertion (Borg 6-20) were obtained. RESULTS: Moderate-intensity quadriceps pain ratings were achieved within 4 min, during which time the average power output was increased from 124 to 138 W. Pain-intensity ratings were unchanged from minutes 4 to 20 (F = 0.94; df = 16, 176; P = 0.52; eta2 = 0.079). Quadriceps RPE responses mimicked the pain responses. To sustain a moderate-intensity quadriceps pain participants reduced power output significantly (F = 7.75; df = 16, 176; P < 0.001; eta2 = 0.413) and in a linear fashion by 21.7 W (15.7%). The changes in % VO2peak were similar in pattern to the changes in power output but smaller in magnitude. CONCLUSIONS: 1) College women can produce and sustain a moderate-intensity quadriceps muscle pain during cycle ergometry, 2) moderate-intensity quadriceps muscle pain is sustained by reducing power output, and 3) sustaining moderate-intensity quadriceps muscle pain during short duration cycling is associated with a "hard" perceptual effort and 69-74% VO2peak.

Adult↗
PubMed2001

Relationship of brain MRI abnormalities and physical functional status in chronic fatigue syndrome.

Chronic Fatigue Syndrome (CFS) is an unexplained illness that is characterized by severe fatigue. Some have suggested that CFS is a "functional somatic syndrome" in which symptoms of fatigue are inappropriately attributed to a serious illness. However, brain magnetic resonance imaging (MRI) data suggest that there may be an organic abnormality associated with CFS. To understand further the significance of brain MRI abnormalities, we examined the relationship between MRI identified brain abnormalities and self-reported physical functional status in 48 subjects with CFS who underwent brain MR imaging and completed the Medical Outcomes Study SF-36. Brain MR images were examined for the presence of abnormalities based on 5 general categories previously shown to be sensitive to differentiating CFS patients from healthy controls. There were significant negative relationships between the presence of brain abnormalities and both the physical functioning (PF) (rho=-.31, p=.03), and physical component summary PCS (rho=-.32, p=.03) subscales of the SF-36. CFS patients with MRI identified brain abnormalities scored significantly lower on both PF (t(1,46) =2.3, p=.026) and the PCS (t(1,41) =2.4, p=.02) than CFS subjects without an identified brain abnormality. When adjusted for age differences only the PF analysis remained significant. However, the effect sizes for both analyses were large indicating meaningful differences in perceived functional status between the groups. These results demonstrate that the presence of brain abnormalities in CFS are significantly related to subjective reports of physical function and that CFS subjects with MRI brain abnormalities report being more physically impaired than those patients without brain abnormalities.

Adult↗
PubMed2000

Muscle pain perception and sympathetic nerve activity to exercise during opioid modulation.

The purpose of this experiment was to examine the effects of the endogenous opioid system on forearm muscle pain and muscle sympathetic nerve activity (MSNA) during dynamic fatiguing exercise. Twelve college-age men (24 +/- 4 yr) performed graded (1-min stages; 30 contractions/min) handgrip to fatigue 1 h after the ingestion of either 60 mg codeine, 50 mg naltrexone, or placebo. Pain (0-10 scale) and exertion (0-10 and 6-20 scales) intensities were measured during the last 15 s of each minute of exercise and every 15 s during recovery. MSNA was measured continuously from the peroneal nerve in the left leg. Pain threshold occurred earlier [1.8 +/- 1, 2. 2 +/- 1, 2.2 +/- 1 J: codeine, naltrexone, and placebo, respectively] and was associated with a lower rating of perceived exertion (RPE) (2.7 +/- 2, 3.6 +/- 2, 3.8 +/- 2: codeine, naltrexone, and placebo, respectively) in the codeine condition compared with either the naltrexone or placebo conditions. There were no main effects (i.e., drugs) or interaction (i.e., drugs x time) for either forearm muscle pain or RPE during exercise [pain: F (2, 22) = 0.69, P = 0.51]. There was no effect of drug on MSNA, heart rate, or blood pressure during baseline, exercise, or recovery. Peak exercise MSNA responses were 21 +/- 1, 21 +/- 2.0, and 21 +/- 2.0 bursts/30 s for codeine, naltrexone, and placebo conditions, respectively. Peak mean arterial pressure responses were 135 +/- 4, 131 +/- 3, and 132 +/- 4 mmHg for codeine, naltrexone, and placebo conditions, respectively. It is concluded that neither 60 mg codeine nor 50 mg naltrexone has an effect on forearm muscle pain, exertion, or MSNA during high- intensity handgrip to fatigue.

Adolescent↗
PubMed1998

A sandwich hybridization assay employing enzyme amplification for termination of specific ribosomal RNA from unpurified cell lysates.

We have employed the power of the cyclic NAD-based enzyme amplification system to the determination of 16S rRNA. This generally applicable system employs two oligonucleotide probes, one of which is captured on a microtiter well surface and the other labeled with alkaline phosphatase. The detection of very low levels of hybridization of the capture probe is then achieved by the means of the ultrasensitive enzyme-amplified assay system, resulting in a highly sensitive, convenient, and rapid technology which can be directly employed on unpurified samples. We have been able to demonstrate the detection of 20 amol (10(7) molecules) of pure rRNA, and specific signals from as few as 2000 bacterial cells have also been demonstrated. The total procedural time can be short-5 to 18 h-depending on the dynamic range and sensitivity required. RNA target in the range of 10(12)-10(8) molecules can be assayed within 5 h. Extending the substrate incubation time enables between 10(11) and 10(7) molecules to be determined within 18 h. The system has great potential use with respect to studying the distribution and physiological states of cellular organisms.

Enzymes↗
PubMed1998

Anxiolytic and blood pressure effects of acute static compared to dynamic exercise.

This experiment tested whether state anxiety and blood pressure responses to exercise were influenced by the type of muscular contraction performed. On testing day 1, 11 volunteers completed one-repetition maximums (1-RMs) separately for the right and left limbs: arm extension, arm flexion, leg extension and leg flexion (8 total exercises). On two subsequent days, which were randomly ordered, subjects completed 24 minutes of either static or dynamic exercise. Both the static and dynamic exercise conditions involved eight 3-min exercise periods performed at an intensity equal to 10% of 1-RM and separated by a 1-min rest period. In the dynamic exercise condition, exercise was performed at a rate of 20 contractions x min(-1). State anxiety and blood pressure were assessed immediately before as well as 3, 13, and 23 minutes following exercise. Heart rate was assessed continuously during exercise, and overall ratings of perceived exertion were obtained during the last 15 seconds of each 3-min exercise period. Two-way repeated measures ANOVAs revealed that state anxiety and systolic blood pressure were reduced to a similar degree following both static and dynamic exercise. It is concluded that anxiety and systolic blood pressure responses to acute exercise are not mediated by the type of muscle contraction performed.

Adult↗
PubMed1998

Sex differences in naturally occurring leg muscle pain and exertion during maximal cycle ergometry.

This investigation examined the role of sex in perceptions of leg muscle pain during exercise. Males (N = 26; age = 23.2 +/- 3.9) and females (N = 26; age = 21.9 +/- 3.5) matched on weekly energy expenditure completed a ramped maximal cycle ergometry test. Leg muscle pain thresholds were determined and pain intensity ratings as well as ratings of perceived exertion were obtained during and after exercise. The power output at pain threshold was lower in females (129.9 +/- 46.5 watts) compared to males (148.2 +/- 56.6 watts). Peak power output and peak pain intensity ratings were lower (P < 0.001) in females (211.3 +/- 39.1 watts; 5.5 +/- 2.9) compared to males (303.6 +/- 27.5 watts; 8.5 +/- 2.3). A Sex X Relative Intensity (i.e., % peak power output) ANOVA revealed that females reported lower pain ratings at each relative intensity examined (F = 17.7; df = 1.50; p < 0.001). The primary conclusion of this investigation is that females rate naturally occurring leg muscle pain as less intense than males when data are relativized to peak power output.

Adult↗
PubMed1997

Naturally occurring muscle pain during exercise: assessment and experimental evidence.

The objectives were: (i) to present a method for assessing muscle pain during exercise, (ii) to provide reliability and validity data in support of the measurement tool, (iii) to test whether leg muscle pain threshold during exercise was related to a commonly used measure of pain threshold pain during test, (iv) to examine the relationship between pain and exertion ratings, (v) to test whether leg muscle pain is related to performance, and (vi) to test whether a large dose of aspirin would delay leg muscle pain threshold and/or reduce pain ratings during exercise. In study 1, seven females and seven males completed three 1-min cycling bouts at three different randomly ordered power outputs. Pain was assessed using a 10-point pain scale. High intraclass correlations (R from 0.88 to 0.98) indicated that pain intensity could be rated reliably using the scale. In study 2, 11 college-aged males (age 21.3 +/- 1.3 yr) performed a ramped (24 W.min-1) maximal cycle ergometry test. A button was depressed when leg muscle pain threshold was reached. Pain threshold occurred near 50% of maximal capacity: 50.3 (+/- 12.9% Wmax), 48.6 (+/- 14.8% VO2max), and 55.8 (+/- 12.9% RPEmax). Pain intensity ratings obtained following pain threshold were positively accelerating function of the relative exercise intensity. Volitional exhaustion was associated with pain ratings of 8.2 (+/- 2.5), a value most closely associated with the verbal anchor "very strong pain." In study 3, participants completed the same maximal exercise test as in study 2 as well as leg cycling at 60 rpm for 8 s at four randomly ordered power outputs (100, 150, 200, and 250 W) on a separate day. Pain and RPE ratings were significantly lower during the 8-s bouts compared to those obtained at the same power outputs during the maximal cycle test. The results suggest that noxious metabolites of muscle contraction play a role in leg muscle pain during exercise. In study 4, moderately active male subjects (N = 19) completed two ramped maximal cycle ergometry tests. Subjects drank a water and Kool-Aid mixture, that either was or was not (placebo) combined with a 20 mg.kg-1 dose of powdered aspirin 60 min before exercise. Paired t-tests revealed no differences between conditions for the measures of exercise intensity at pain threshold [aspirin vs placebo mean (+/- SD)]: power output: 150 (+/- 60.3 W) versus 153.5 (+/- 64.8 W); VO2: 21.3 (+/- 8.6 mL.kg-1.min-1) versus 22.1 (+/- 10.0 mL.kg-1.min-1); and RPE: 10.9 (+/- 3.1) versus 11.4 (+/- 2.9). Repeated measures ANOVA revealed no significant condition main effect or condition by trial interaction for pain responses during recovery or during exercise at 60, 70, 80, 90, and 100% of each condition's peak power output. It is concluded that the perception of leg muscle pain intensity during cycle ergometry: (i) is reliably and validly measured using the developed 10-point pain scale, (ii) covaries as a function of objective exercise stimuli such as power output, (iii) is distinct from RPE, (iv) is unrelated to performance of the type employed here, and (v) is not altered by the ingestion of 20 mg.kg-1 acetylsalicylic acid 1 h prior to the exercise bout.

Adolescent↗
PubMed1997

Body image in adulthood: a projective approach.

A sample of 210 persons varying by age (young adults, middle-aged, older adults), gender, and relationship status (single or involved) were administered the Holtzman Inkblot Technique (HIT) and Geriatric Draw-A-Person (G-DAP) to ascertain projectively assessed aspects of body image in adulthood. Results suggested that both the HIT and G-DAP were sensitive to the effects of age and gender, wherein young adults scored higher on both HIT Barrier and Penetration than both middle-aged or older adults. In addition, G-DAP scores favored young adults. HIT Penetration scores varied by both age and relationship status.

Adolescent↗
PubMed1996

Advances in immunoassay technology.

Major developments continue to be reported in key areas of immunoassay technology. Following the development of excellent signal generation methods, attention has shifted to the development of immunochemical methods and instrumentation to provide convenient systems of high performance. Important advances have been made in the design of immunochemical approaches that permit the replacement of competitive format assays for small molecules, such as drugs, metabolites and pollutants, with non-competitive formats, bringing advantages previously seen only with large molecular analytes. Bispecific antibodies and recombinant proteins are also beginning to impact immunodiagnostics, with the promise of even more highly specified reagents. Improvements in automation have brought the facility of homogeneous systems to high-throughput and high-performance heterogeneous systems. Similarly, 'point of need' testing continues to progress. Through all of these advances, systems are evolving according to the needs of users in terms of operator convenience, accuracy, specificity, speed, robustness, and sensitivity.

Animals↗
PubMed1996

Post-exercise analgesia: replication and extension.

This study was designed to investigate whether post-exercise analgesia occurs following an ad lib exercise routine. All of the 17 male participants exercised on a regular basis. In an exercise setting (student gymnasium) they participated in 20 min of self-selected exercise, while in the neutral setting (laboratory) they rested quietly for 20 min. Pain was induced via the gross pressure device. Pain threshold and pain tolerance were measured twice, with an interval of 20 min, in both the exercise and the neutral setting. Pain threshold was stable in the exercise setting. A significant increase in pain tolerance followed the 20 min bout of exercise, indicating a post-exercise analgesic response. These results support the prediction that the analgesic effect of exercise is not limited to controlled experimental conditions, but generalizes to naturally occurring situations.

Analgesia↗
PubMed1996

Eating disorder symptoms in former female college gymnasts: relations with body composition.

The purpose of this investigation was to describe eating disorder symptoms in 36.6 +/- 3.8-y-old former college gymnasts as well as relations between body dissatisfaction and body composition. Former college gymnasts (n = 22) and age-(mean +/- SE difference: 0.05 +/- 0.26 y), height-(0.47 +/- 0.75 cm), and weight-matched (2.20 +/- 0.30 kg) control subjects (n = 22) participated. Current and past symptoms were assessed by using the Eating Disorders Inventory-2 (EDI-2) and visual analog scales. EDI-2 body-dissatisfaction scores were correlated with assessments of body composition by dual-energy X-ray absorptiometry. Weight preoccupation was stable across the life span for control subjects but was lower before former gymnasts had begun gymnastics training and higher for former gymnasts when they were participating in college gymnastics (P = 0.03). Current levels of body dissatisfaction were more strongly related to actual minus ideal body-weight discrepancy scores (r = 0.77) than to percentage fat (r = 0.50) for the former gymnasts whereas the opposite was true for the control subjects (r = 0.51 and 0.77, respectively). These results suggest that symptoms of eating disorders abate after retirement from gymnastics and that concerns about achieving an ideal body may be a more important determinant of body dissatisfaction than percentage body fat for gymnasts.

Absorptiometry, Photon↗
PubMed1993

Determination of one thousandth of an attomole (1 zeptomole) of alkaline phosphatase: application in an immunoassay of proinsulin.

Enzyme amplification has proved to be a highly sensitive quantification technique for immunoassays. We have shown that by using a fluorescent end-point, even more sensitive enzyme amplification assays can be generated than hitherto reported. We describe some general properties of this system and demonstrate its application in an assay for human proinsulin in plasma. The detection system can be used to measure less than one thousandth of an attomole (1 zeptomole) of alkaline phosphatase, equivalent to about 350 molecules of alkaline phosphatase per well of a microtiter plate. We have used this system to construct a proinsulin assay with a sensitivity of 0.017 pmol/L.

Alkaline Phosphatase↗
PubMed1992

Amplified enzyme-linked immunoassay of human proinsulin in serum (detection limit: 0.1 pmol/L).

We describe an amplified enzyme-linked immunoassay of human proinsulin in serum that detects intact proinsulin and both the 32/33 and 65/66 split forms. The method uses the IgG fraction of a polyclonal antibody raised in a guinea pig against intact proinsulin, which we used to coat plastic microtiter plates. A sandwich was formed with proinsulin by using a monoclonal antibody against C-peptide labeled with alkaline phosphatase. We quantified the reaction by using the enzyme amplification procedure, which detected as little intact proinsulin as 0.1 pmol/L. We found no cross-reactivity with C-peptide in the assay, and decreased recovery attributable to the presence of insulin could be demonstrated only with a 30-fold excess of this hormone over proinsulin.

Alkaline Phosphatase↗