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Biomedical subjects

J Loehr

Publications and source records attributed to J Loehr.

At least 19 recordsLinked to original sources

Evidence for cryptic glacial refugia from North American mountain sheep mitochondrial DNA.

The separation of populations by ice sheets into large refugia can account for much of the genetic diversity found in present day populations. The evolutionary implications of small glacial refugia have not been as thoroughly explored. To examine refugial origins of North American mountain sheep Ovis spp., we analyzed a 604 bp portion of the mitochondrial DNA (mtDNA) control region from 223 O. dalli and O. canadensis. Major refugia were identified in eastern Beringia and southern North America, and we found evidence for two smaller refugia situated between the Laurentide and Cordilleran glaciers. Our results are the first to demonstrate support for survival of any organism in the latter two refugia. These refugia also appear to have conserved a genetic signal that confirms past hybridization of O. dalli and O. canadensis.

Altitude↗

The Sony Ericsson WTA Tour 10 year age eligibility and professional development review.

Concerns have long existed over the participation of adolescent athletes in professional sports. In 2004, the Sony Ericsson WTA Tour (WTA Tour) commissioned a Professional Development Advisory Panel (PDAP) to evaluate the WTA Tour's age eligibility rule (AER) and professional development programmes (PDPs) for female tennis players since their inception in 1995. More than 75% of the 628 respondents supported the principles of the AER, and 90% indicated a need for PDPs. Statistical analysis of WTA Tour players' careers found that premature retirements (players leaving the Tour at or before age 21) decreased significantly from 7% before the AER to less than 1% afterward, and median career length increased by 43%. The PDAP recommends that the WTA Tour continues a phased-in, developmentally appropriate AER, enhances the PDPs, and works with other sport governing bodies to coordinate rules and programmes at earlier ages to aid the transition of adolescents into adult sports.

Adolescent↗

The making of a corporate athlete.

Management theorists have long sought to identify precisely what makes some people flourish under pressure and others fold. But they have come up with only partial answers: rich material rewards, the right culture, management by objectives. The problem with most approaches is that they deal with people only from the neck up, connecting high performance primarily with cognitive capacity. Authors Loehr and Schwartz argue that a successful approach to sustained high performance must consider the person as a whole. Executives are, in effect, "corporate athletes." If they are to perform at high levels over the long haul, they must train in the systematic, multilevel way that athletes do. Rooted in two decades of work with world-class atheletes, the integrated theory of performance management addresses the body, the emotions, the mind, and the spirit through a model the authors call the performance pyramid. At its foundation is physical well-being. Above that rest emotional health, then mental acuity, and, finally, a spiritual purpose. Each level profoundly influences the others, and all must be addressed together to avoid compromising performance. Rigorous exercise, for instance, can produce a sense of emotional well-being, clearing the way for peak mental performance. Rituals that promote oscillation--the rhythmic expenditure and recovery of energy-link the levels of the pyramid and lead to the ideal performance state. The authors offer case studies of executives who have used the model to increase professional performance and improve the quality of their lives. In a corporate environment that is changing at warp speed, performing consistently at high levels is more necessary than ever. Companies can't afford to address employees' cognitive capacities while ignoring their physical, emotional, and spiritual well-being.

Adaptation, Psychological↗

Alpine and cross-country skiing after total hip replacement: 2 cohorts of 50 patients each, one active, the other inactive in skiing, followed for 5-10 years.

2 groups of 50 patients each, matched for age, weight, height, gender and type of implant, were clinically and radiographically examined after THR. Group A regularly carried out alpine skiing and/or cross-country skiing, while group B did no winter sports. At 5 years, no signs of loosening were found in group A, whereas 5/60 implants in group B had signs of loosening, mostly of the femoral component (p < 0.05). At 10 years, 30 patients remained in group A and 27 in group B. No new cases of loosening were found in group B, but 2/30 cases in group A. There was a higher (p < 0.05) average wear rate in group A (2.1 mm) than in group B (1.5 mm). The wear rate was particularly high (3-4 mm) in physically very active patients in group A with localized osteolysis at the interface. It seems likely that in an even longer follow-up, the number of cases of aseptic loosening would be greater in group A than group B. Our findings, combined with the results of previously-published biomechanical studies, do not provide any evidence that controlled alpine and/ or cross-country skiing has a negative effect on the acetabular or femoral component of hip replacements. The results of the biomechanical studies indicate, however, that it is advantageous to avoid short-radius turns on steep slopes or moguls.

Aged↗

[Not Available].

Explore the source record for details and available documents.

Journal Article↗

Issues of sexuality in older women.

The aim of this exploratory research study was to investigate the attitudes of women over 60 toward sexuality and intimacy, to elicit which issues concerning sexuality and intimacy are important to them, and to gather their perceptions of how issues of sexuality and intimacy are addressed by the medical profession. Fourteen women aged 60-85 participated in three focus group interviews organized in Kingston, Ontario, Canada. We qualitatively measured recurring themes in attitudes about sexuality. Although they grew up in a generation when sex and sexuality were rarely discussed, these older women did not have any problem talking about sex, sexuality, and their attitudes towards these topics within the focus group setting. The participants felt on the whole, that sexuality is, and will continue to be, an important part of their lives. There was consensus that they would feel comfortable talking to their family doctor about their own or their partner's problems if asked but might not volunteer the information. Sex and sexuality are important issues to these older women. Male impotence is the most common problem that affects these older women's sex lives. They need more information about normal changes with aging that affect sexuality of older women and men. These women have rarely been afforded the opportunity to discuss sexuality with their physician. The small sample size of this pilot study provided useful information but is not definitive in its conclusions. Further research is needed to determine physician attitudes and practices concerning sex and sexuality in this age group.

Aged↗

Levels of the mitochondrial endonuclease during rat cardiac development implicate a role for the enzyme in repair of oxidative damage in mitochondrial DNA.

Mammalian heart mitochondria (MT) contain a potent Mg(2+)-dependent DNA endonuclease that becomes soluble once isolated mitochondria are disrupted using detergent. The level of this endonuclease was previously found to be markedly elevated in adult rat heart compared to other adult rat tissues. Among tissues, the level of the MT endonuclease does not appear to be correlated with the rate of MT DNA replication but rather with the rate of oxidative metabolism [Houmiel, K.L., Gerschenson, M. and Low, R.L., 1991. Biochimica Biophysica Acta 1079: 197-202]. In the present study, the level of the endonuclease has been quantitated both during rat cardiac development, from gestational day 18 through adulthood, and in cultured rat heart myoblasts. Surprisingly, the specific activity of the MT endonuclease in fetal and newborn mitochondria is high. The values are greater than 50% of that seen in the adult even though the mitochondria at this period of heart development are few and structurally disorganized. Remarkably, there is a burst of endonuclease activity at day 2 which accompanies a similar, transient elevation of respiratory complex I and IV activities. At later times, the endonuclease activity gradually increases until adulthood and correlates with steady increases in MT DNA and DNA polymerase-gamma. In cultured myoblasts, the level of the endonuclease increases about seven-fold as the growing cells reach confluency and differentiate into myotubes. These variations in the specific activity of the endonuclease, when considered along with other properties of the enzyme suggest that the endonuclease may serve a role in the removal of oxidative damage in MT DNA incurred from respiration.

Animals↗

Isolated dislocation of the radial head.

Fifty-four patients (12 bilateral) with isolated dislocations of the radial head were encountered over a 20-year period. The congenital varieties (26 patients) included isolated unilateral, familial, synostosis-related, and syndrome-related. The acquired types (28 patients) involved trauma, neuromuscular impairment, or adaptive dislodgments. Acute, traumatic dislocation (17 patients) was the most common presentation. Others were diagnosed incidentally, or associated with discomfort, dysfunction, or deformity. Closed reduction of an acute traumatic dislocation was generally successful (16 of 17 patients). Realignment attempts (three cases) on late diagnosed traumatic cases and isolated congenital types were invariably unsuccessful, eventually requiring radial head excision. Four patients underwent excision of the head of the radius as primary treatment.

Adolescent↗

Osteoblastoma of the cervical spine. Case report.

This case report demonstrates the importance of an exact workup in unclear neck pain. An osteoblastoma situated in the pedicule of C6 is described. During 36 months there was no diagnosis made. Only by a CT-scan a tumorous lesion in the pedicule of C6 with the histology of a benign osteoblastoma was found. The therapy consisted in excision of the tumor of C6. A fusion was added because important parts of the joint were involved.

Adult↗

[Arthroplasty of the elbow].

Elbow arthroplasty is still one of the less frequently performed joint replacement procedures. It is technically demanding, and numerous complications are possible. It is therefore indicated mainly in severely handicapped patients in whom all other alternatives have been attempted. A review of the literature relating to arthroplasties monitored over follow-up periods of more than 5 years shows that the results are now quite acceptable. They are far better than those seen following most resection arthroplasties. The results achieved with our GSB III prosthesis are compared with those obtained with other prosthetic devices in current use. It appears that in a large proportion of cases our prosthesis allows a good range of painfree motion, which we attribute in part to the operative approach used. The complication rate appears to be relatively low.

Adult↗

Semiconstrained elbow prostheses with special reference to the GSB III prosthesis.

Fully constrained metal-to-metal elbow prostheses are not used anymore because of a high loosening rate. Today semiconstrained or condylar prostheses are the two possibilities when replacement of a destroyed elbow joint is considered. A careful analysis of the most recent publications in the world literature reveals a high complication rate for both types of prostheses, each one having specific advantages and disadvantages. The Gschwend-Scheier-Bähler (GSB) III prosthesis is a semiconstrained prosthesis, requires little bone resection, and is therefore easily salvaged. The results in regard to pain relief and improvement in range of motion are satisfactory in a high percentage of patients. The rate of lasting complications is lower than with most of the other prostheses. The authors' transtricipital approach is also a factor that contributes to the high success rate. In case of a failed arthroplasty the authors' method of reconstructing the humeral condyles allows a better salvage.

Adult↗

Spontaneous rupture of the quadriceps tendon and patellar ligament during treatment for chronic renal failure.

The quadriceps tendon and patellar ligament rupture rarely, even when under great stress or trauma, but can rupture spontaneously in patients with chronic diseases such as gout, rheumatoid arthritis and renal disease. Several factors probably combine to weaken the tendon, including an impoverished local vascular supply, repeated microtrauma and secondary hypoparathyroidism with osteodystrophy. In the three cases reported here, one of which was bilateral, the patients were being treated for chronic renal disease; surgical repair of the tendons led to sound healing and a return to normal function of the joints.

Adult↗

Deoxythymidine sugars are not direct precursors of DNA-thymine.

A theoretical model for the kinetics of uptake of a putative precursor molecule into nucleotide pools and into replicating DNA has been developed. The relationship between the accumulation of radioactively labeled precursors in the pool and the appearance of radioactivity in DNA is then derived. Experiments have been carried out in bacteria to compare the uptake of radioactive thymine into deoxythymidine triphosphate, deoxythymidine diphosphate sugars, and DNA to test the suitability of either compound as the direct precursor of thymine in DNA. New one-dimensional, thin-layer chromatographic procedures were used to determine the specific activity of deoxythymidine triphosphate and deoxythymidine triphosphate and deoxythymidine diphosphate sugars in growing cultures of 32PO4-labeled Escherichia coli during pulse labeling with [3H]-thymine. A comparison of the experimental data with our theoretical model supports the hypothesis that deoxythymidine triphosphate, but not deoxythymidine sugar, is the direct precursor of thymine in normally replicating DNA in vivo.

DNA Replication↗