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R R Clark

Publications and source records attributed to R R Clark.

At least 19 recordsLinked to original sources
PubMed2006

Pollicisation of the index metacarpal based on the first dorsal metacarpal artery.

We present our experience of two cases in which we carried out pollicisation of the index metacarpal based on the first dorsal metacarpal artery and venae comitans. Both cases were complex severe hand injuries where the initial injury was the result of a firework exploding while held in the hand. In both cases the radial side of the superficial palmar arch was destroyed by the injury. In both cases there was virtually complete loss of the thumb ray and amputation of the index through the base of the proximal phalanx. A useful opposition post has been created from vascularised index metacarpal with free flap soft tissue reconstruction.

Amputation, Traumatic↗
PubMed2001

Ductal lavage for detection of cellular atypia in women at high risk for breast cancer.

BACKGROUND: Breast cancer originates in breast epithelium and is associated with progressive molecular and morphologic changes. Women with atypical breast ductal epithelial cells have an increased relative risk of breast cancer. In this study, ductal lavage, a new procedure for collecting ductal cells with a microcatheter, was compared with nipple aspiration with regard to safety, tolerability, and the ability to detect abnormal breast epithelial cells. METHODS: Women at high risk for breast cancer who had nonsuspicious mammograms and clinical breast examinations underwent nipple aspiration followed by lavage of fluid-yielding ducts. All statistical tests were two-sided. RESULTS: The 507 women enrolled included 291 (57%) with a history of breast cancer and 199 (39%) with a 5-year Gail risk for breast cancer of 1.7% or more. Nipple aspirate fluid (NAF) samples were evaluated cytologically for 417 women, and ductal lavage samples were evaluated for 383 women. Adequate samples for diagnosis were collected from 111 (27%) and 299 (78%) women, respectively. A median of 13,500 epithelial cells per duct (range, 43-492,000 cells) was collected by ductal lavage compared with a median of 120 epithelial cells per breast (range, 10-74,300) collected by nipple aspiration. For ductal lavage, 92 (24%) subjects had abnormal cells that were mildly (17%) or markedly (6%) atypical or malignant (<1%). For NAF, corresponding percentages were 6%, 3%, and fewer than 1%. Ductal lavage detected abnormal intraductal breast cells 3.2 times more often than nipple aspiration (79 versus 25 breasts; McNemar's test, P<.001). No serious procedure-related adverse events were reported. CONCLUSIONS: Large numbers of ductal cells can be collected by ductal lavage to detect atypical cellular changes within the breast. Ductal lavage is a safe and well-tolerated procedure and is a more sensitive method of detecting cellular atypia than nipple aspiration.

Adult↗
PubMed2001

Clinical service standards at academic health centers.

OBJECTIVE: To describe the content and variability for clinical service standards related to quality of care among a convenience sample of academic health centers. DESIGN: We used the membership of the University HealthSystem Consortium, an alliance of academic health centers in the United States for clinical services, to survey electronically 53 of these centers regarding clinical service standards. The survey evaluated service standards in four areas; general communications, communications between physicians, ambulatory and inpatient clinical services and administrative standards. RESULTS: Thirty-four institutions responded to the survey (64%). Of these, 16 (47%) had clinical service standards, while the remaining 18 (53%) had not established formal standards. A few of the centers had established standards for patient communications, such as policies for answering telephones by staff. More had developed standards for communications between physicians and most centers had established standards for appointment availability, especially for urgent visits. However, clinical service standards were less typical for inpatient consultative or diagnostic services. A small number of the academic health centers had standards for hours of operation and for handling administrative matters, such as patient complaints. For many clinical service standards at the centers, there were notable variations (e.g. non-urgent primary care visits ranged 3-14 days). CONCLUSION: Some academic health centers have developed and implemented patient-centered clinical service standards for diverse areas of practice, however, the standards used appear to vary for some aspects of care, but not for others.

Academic Medical Centers↗
PubMed2000

New equations improve NIR prediction of body fat among high school wrestlers.

STUDY DESIGN: Methodologic study to derive prediction equations for percent body fat (%BF). OBJECTIVES: To develop valid regression equations using NIR to assess body composition among high school wrestlers. BACKGROUND: Clinicians need a portable, fast, and simple field method for assessing body composition among wrestlers. Near-infrared photospectrometry (NIR) meets these criteria, but its efficacy has been challenged. METHODS AND MEASURES: Subjects were 150 high school wrestlers from 2 Midwestern states with mean +/- SD age of 16.3 +/- 1.1 yrs, weight of 69.5 +/- 11.7 kg, and height of 174.4 +/- 7.0 cm. Relative body fatness (%BF) determined from hydrostatic weighing was the criterion measure, and NIR optical density (OD) measurements at multiple sites, plus height, weight, and body mass index (BMI) were the predictor variables. RESULTS: Four equations were developed with multiple R2s that varied from .530 to .693, root mean squared errors varied from 2.8% BF to 3.4% BF, and prediction errors varied from 2.9% BF to 3.1% BF. The best equation used OD measurements at the biceps, triceps, and thigh sites, BMI, and age. The root mean squared error and prediction error for all 4 equations were equal to or smaller than for a skinfold equation commonly used with wrestlers. CONCLUSION: The results substantiate the validity of NIR for predicting % BF among high school wrestlers. Cross-validation of these equations is warranted.

Adipose Tissue↗
PubMed1998

Glucose transporter expression in brain: relationship to cerebral glucose utilization.

Glucose is the principle energy source for mammalian brain. Delivery of glucose from the blood to the brain requires its transport across the endothelial cells of the blood-brain barrier and across the plasma membranes of neurons and glia, which is mediated by the facilitative glucose transporter proteins. The two primary glucose transporter isoforms which function in cerebral glucose metabolism are GLUT1 and GLUT3. GLUT1 is the primary transporter in the blood-brain barrier, choroid plexus, ependyma, and glia; GLUT3 is the neuronal glucose transporter. The levels of expression of both transporters are regulated in concert with metabolic demand and regional rates of cerebral glucose utilization. We present several experimental paradigms in which alterations in energetic demand and/or substrate supply affect glucose transporter expression. These include normal cerebral development in the rat, Alzheimer's disease, neuronal differentiation in vitro, and dehydration in the rat.

Aging↗
PubMed1997

Clomiphene citrate ovulation induction in combination with a timed intrauterine insemination: the value of urinary luteinizing hormone versus human chorionic gonadotropin timing.

OBJECTIVE: To evaluate the clinical pregnancy rates (PRs) in anovulatory, male factor, and unexplained infertility using clomiphene citrate (CC) with an IUI and to evaluate the difference in PRs between urinary LH testing and hCG administration for timing of the IUI. DESIGN: Retrospective clinical study. SETTING: Academic, tertiary care fertility center. PATIENT(S): One hundred thirty-eight couples (432 cycles) undergoing IUI with CC ovulation induction as a treatment for unexplained, anovulatory, or male factor infertility were selected. INTERVENTION(S): All women with unexplained or male factor infertility received CC at a dose of 50 mg/d, and those with anovulation received CC at a dose ranging from 50 to 200 mg/d. All women in the study received a single IUI either the morning after a urinary LH surge or 36 to 38 hours after an evening hCG injection. MAIN OUTCOME MEASURE(S): Clinical PR. RESULT(S): There were no differences in the clinical PRs between LH testing or hCG administration in any of the three groups. Clinical PRs were extremely low in the male factor infertility group regardless of the timing used. CONCLUSION(S): These data suggest that the success of IUI with CC is not dependent on the method used to establish the timing for the IUI. In couples undergoing IUI with CC, the use of urinary LH testing may result in lower costs by reducing patient visits and the midcycle ultrasound.

Adult↗
PubMed1995

An evaluation of instrumented tank rowing for objective assessment of rowing performance.

The aim of this study was to evaluate instrumented tank rowing for its ability to measure objectively the individual performance components of power output and rowing skill in a sample of collegiate rowers. The measuring system utilized strain gauges and a potentiometer to measure force on the oar and its angular position at each sampling interval. Power outputs were calculated for 13 collegiate rowers tested individually during a 30-s bout of maximal work. Results from this 'tank test' were compared with power measurements from both Concept II (CII) and Stanford rowing ergometers and from a Wingate test, using similar 30-s bouts of maximal work. Significant differences (P < 0.05) were found between the tank test and all other modes of testing except the Wingate test for average power. These differences can probably be attributed to the different methods of power measurement and to the different skill-dependence associated with the tests. For each subject, peak power and average power per stroke were measured from the rowing tests. The CII and Stanford test data for all subjects were correlated with their tank test data. Similar correlations were made between tank data and the peak and mean power from the Wingate test. The strongest correlation was in peak power measurements with the Wingate test (r = 0.92, P = 0.0001). Instrumented tank rowing provided objective information on individual power output unique from rowing and cycling ergometry. Of the various tests, the tank test appeared to provide better and more complete power data specific to rowing. This method also provided objective data for interpreting various aspects of rowing skill, including oar handling, technical efficiency, consistency, stroke frequency, stroke recovery ratio and stroke length. Instrumented tank rowing has substantial potential as a coaching tool or as a self-training device for improving rowing ability.

Adult↗
PubMed1995

The Wisconsin wrestling minimum weight project: a model for weight control among high school wrestlers.

In 1989, the Wisconsin Interscholastic Athletic Association implemented a project including new rules and an educational program, consistent with ACSM and AMA guidelines, to curtail "weight cutting" among high-school wrestlers. The project included skinfold estimates of body fatness to determine a minimum competitive weight, a limit on weekly weight loss, and presentation of nutrition education information to help wrestlers diet effectively. Implementation of the project has overcome a variety of obstacles and has received widespread endorsement from parents, teachers, wrestlers, and coaches. The success of this project offers a model for other states to emulate and should encourage clinicians in other sports to initiate interventions addressing these unhealthy weight loss behaviors.

Adipose Tissue↗
PubMed1994

Cross-validation of methods to predict body fat in African-American and Caucasian collegiate football players.

Eight skinfold (SF) equations and bioelectrical impedance analysis (BIA) were cross-validated in 71 Division IA college football players. Criterion percent body fat (%FAT) was determined by hydrostatic weighing (HW) and computed from body density (BD) for African Americans (n = 28) and Caucasians (n = 43). Results were analyzed by method, with position and race effects examined simultaneously using a two-way ANOVA. Analysis included computation of mean difference (MD), correlation (r), standard error of estimate (SEE), and total error (TE). Skinfolds had MDs ranging from -1.8 to 2.9%, correlations from .85 to .93, SEEs from 2.3 to 3.2%, and TEs from 2.3 to 4.2%. Bioelectrical impedance analysis was significantly different from HW and yielded the highest MD (3.8%), lowest correlation (r = .78), highest SEE (3.9%), and highest TE (5.4%). The Jackson and Pollock (1978) SF equation provided the most valid prediction of HW-determined %FAT in a racially mixed sample of college football players, demonstrating the highest correlation, lowest SEE and TE, and an intercept and slope not significantly different than 0.0 and 1.0, respectively.

Adipose Tissue↗
PubMed1994

Operative laparoscopy for the treatment of localized chronic pelvic-abdominal pain caused by postoperative adhesions.

One hundred fifty-six patients with chronic abdominal pain associated with postoperative adhesions were treated with laser laparoscopy. Eighty-eight percent of these patients had complete relief, 9% had satisfactory relief, and 3% required a second laparoscopy to lyse recurrent adhesions. It is concluded that chronic abdominal pain associated with adhesions can be treated successfully with laser laparoscopy.

Abdominal Pain↗
PubMed1993

A comparison of methods to predict minimal weight in high school wrestlers.

The purpose of this study was to compare the accuracy of body fat determinations and subsequent calculation of minimal weight (MW) by dual energy x-ray absorptiometry (DEXA), bioelectrical impedance (BIA), near-infrared photospectometry (NIR), and anthropometry (LOHMAN). Necessitated by mandatory state minimal weight testing, the methods were cross-validated on 95 Wisconsin high school wrestlers (mean +/- SD; age: 15.1 +/- 1.2 yr, height: 170.4 +/- 7.1 cm, weight: 63.4 +/- 9.8 kg). MW, defined as fat-free body/0.93, determined by hydrostatic weighing (HW) and residual volume via O2 dilution, served as the criterion. The validity of the four selected MW predictions were evaluated against HW by examining mean differences (MD), standard deviation differences (SDD), correlations (r), standard error of estimate (SEE), and total errors (TE). Statistically significant differences were shown between the methods and the criterion by t-tests; however, these were clinically small in Lohman (0.6 kg) and BIA (0.9 kg). TE ranged from 2.25 kg (Lohman) to 6.03 kg (NIR). The results indicated that Lohman skinfold equation provided the most accurate prediction of MW, demonstrating the highest correlation (0.972), lowest MD (0.6 kg), lowest SEE (2.12 kg), and lowest TE (2.25 kg) of the methods evaluated.

Absorptiometry, Photon↗
PubMed1993

Prediction of percent body fat in adult males using dual energy x-ray absorptiometry, skinfolds, and hydrostatic weighing.

The purpose of this study was to compare the prediction of percent body fat (%FAT) by dual energy x-ray absorptiometry (DXA), skinfolds (SF), and hydrostatic weighing (HW) in adult males. Subjects were 35 adult male Caucasians (mean +/- SD; age: 39.1 +/- 14.0 yr, height: 180.6 +/- 5.3 cm, weight: 81.0 +/- 11.1 kg). %FAT, determined by HW with residual volume determined via O2 dilution, served as the criterion. DXA %FAT was determined by the Norland XR-26 (XR-26) bone densitometer and by the SF equations of Jackson and Pollock (JP) (1978), and Lohman (LOH) (1981). Criterion referenced validation included analyzing mean (+/- SD) %FAT values using a one-way ANOVA for significance, comparison of mean differences (MD), correlations (r), standard error of estimates (SEE), and total errors (TE). Significant differences were found between means of each method. The r (0.91) and SEE (3.0 %FAT) for DXA compare favorably with the established SF methods of JP and LOH for predicting %FAT; however, DXA demonstrated the largest MD (3.9 %FAT) and TE (5.2 %FAT). Regression analysis yields HW = 0.79* DXA + 0.56. The results do not support earlier research that found no significant difference between HW and DXA %FAT in males. The study suggests the density of the fat-free body (DFFB) is not constant, and that the variation in bone mineral content affects the DFFB, which contributes to the differences between DXA and HW %FAT. We recommend further research to identify inconsistencies between manufacturers of DXA equipment in prediction of %FAT in males.

Adipose Tissue↗
PubMed1988

Characteristics and performance of male citizen cross-country ski racers.

Forty-three male citizen or recreational cross-country (X-C) ski racers (aged 31 +/- 4.4 years) were tested to determine their weight (BW) and percent body fat (BF), maximal oxygen uptake (VO2max), quadriceps (Quad), hamstrings (Ham) and upper body (UBS) isokinetic strength (60 degrees, 180 degrees, 240 degrees/s), and Quad endurance. In addition, skiers filled out a questionnaire to determine their skiing experience and to see what other activities they participated in. All these variables were run through a stepwise regression procedure to see which characteristics best predicted performance in a 10 km X-C ski race. The relatively high VO2max of 56.6 ml O2/kg/min and low BF of 10.1% indicate this group to be a very fit subset of the general population. All the skiers were active in other sports on a year-round basis. Of the variables studied, UBS, VO2max, and Quad strength were all significant determinants of 10 km race performance, yielding a multiple R of 0.78. Quad endurance, Ham strength, BW, BF, and experience did not significantly contribute toward the prediction of performance. It is felt that a proper training program for the citizen X-C skier should strive to maximize upper body strength as well as one's aerobic capacity.

Adult↗
PubMed1979

Degradation of polychlorinated biphenyls by mixed microbial cultures.

Three different enriched mixed cultures capable of degrading polychlorinated biphenylas were isolated from two soil samples and a river sediment, respectively. The predominant organisms found in all three mixed cultures were Alcaligenes odorans, Alcaligenes dentrificans, and an unidentified bacterium. The polychlorinated biphenyl isomers that were more water soluble and had lower chlorination were not only degraded at a faster rate than those that were less water soluble and had higher chlorination, but were also more completely utilized by these mixed cultures. This resulted in the presence in the environment of polychlorinated biphenyl residues consisting mainly of higher-chlorinated isomers. A form of cometabolism of polychlorinated biphenyls was also found with these cultures in the presence of acetate as the cosubstrate.

Acetates↗
PubMed1978

Cigarette smoking in social interaction.

Studied behavior patterns by smokers and others in social interaction correlated with various behaviors comprising cigarette smoking. Field observation methods were used in observing 91 smokers in 117 social interaction settings. Settings were chosen to vary in degree of intimacy between participants in social interaction, and in degree of physical activity. Reliability of observations was established using independent field observers and raters of a videotape of one interaction. Findings generally were that smoking behaviors occur at points in the interaction when the smoker is relatively uninvolved and passive in the context of the social interaction. It is speculated that smoking is a form of self-involvement which is incompatible, on a momentary basis, with active social involvement.

Adolescent↗