The efficacy of carbohydrate supplementation and chronic high- carbohydrate diets for improving endurance performance

Carbohydrate (CHO) is the body's most limited fuel and the most heavily metabolized during moderate-intensity exercise. For this reason it is recommended that endurance athletes consume a high-CHO diet (8-10 g CHO . kg body weight-1 . day-1) to enhance training and performance. A review of the literature supports the benefits of CHO supplementation on endurance performance. The benefits of chronic high-CHO diets on endurance performance are not as clear. Recent evidence suggests that a high-CHO diet may be necessary for optimal adaptations to training. However, the paucity of date in this area precludes any concrete conclusions. The practicality of high-CHO diets is not well understood. The available evidence would indicate that a high-CHO diet is the best dietary recommendation for endurance athletes.     

Is whole grain intake associated with reduced total and cause-specific death rates in older women? The Iowa Women's Health Study.

OBJECTIVES: This study sought to determine whether nutrient-rich whole grains reduce mortality risk. METHODS: The study included 38,740 Iowa women, aged 55 to 69 years. A food frequency questionnaire was used to obtain data on grain intake. RESULTS: Median whole grain intake quintiles ranged from a median of 0.2 to more than 3 servings per day. Women with higher intakes had healthier lifestyles and less baseline disease. The total death rate decreased in increasing quintiles, and the pattern repeated for cancer, cardiovascular disease, and other causes combined. Adjusted for lifestyle and baseline disease, the relative hazard rate ratio for total death was about 0.85 in daily consumers of whole grain. Findings persisted in strata of baseline healthy and diseased and were not explained by dietary fiber. Rates of total mortality, but not cardiovascular disease mortality, were higher among frequent consumers of refined grain. CONCLUSIONS: Total mortality risk was inversely associated with whole grain intake and positively associated with refined grain intake. Refined grains contributed more than 20% of energy intake, and whole grains contributed 1%. Substitution of whole for refined grain may reduce chronic disease risk in the United States.     

Dietary creatine monohydrate supplementation.

This paper summarizes and interprets the research published about physiological aspects of dietary supplementation with creatine monohydrate and the effects on physical performance. A nitrogenous molecule that occurs naturally in the flesh consumed by meat-eaters, creatine is also synthesized endogenously and is stored primarily in skeletal muscle. The research literature in which direct measurements of muscle creatine content have been reported indicates that most, but not all, subjects respond to "creatine loading" by increasing the total intramuscular concentration of creatine, including the concentration of phosphocreatine. The factors that affect muscle creatine stores are reviewed, as are the widely ranging results on physical performance. The mechanism of action by which increased intramuscular creatine could enhance performance is not yet clear. Original speculation was that increased phosphocreatine levels prior to commencing exercise, in conjunction with higher free creatine concentration, would prolong the time required until performance-limiting levels of phosphocreatine were reached during intense exercise. It was also speculated that restoration of phosphocreatine levels between bouts of such exercise would be more rapid. More recent studies question such speculation. This review includes a discussion of what is known about the health risks and side-effects associated with creatine loading. The paper concludes with speculation about the unprecedented attention given to creatine supplementation by recreational and competitive athletes and the media.     

Predictability of reformatted computed tomography for pre-operative planning of endosseous implants

OBJECTIVES: To determine the reliability of reformatted 2D-CT for pre-operative planning of implant placement. METHODS: One hundred consecutive partially or fully edentate patients underwent 2-D reformatted CT pre-operative planning and subsequent implant placement. The number, site and size of the implants, the available bone height and anatomical complications were recorded. The pre-operative planning and the outcome at surgery were compared statistically using a percentage agreement and Kendall's correlation coefficient. RESULTS: Agreement between the pre- and intra-operative data was good for the number of implants (60%) and the selected sites (70%). From a total of 416 implants planned, 21 implants could not be placed because of intra-operative findings. Agreement was relatively poor for implant size (44%) and anatomical complications (46%). Kendall's correlation coefficient was highest for the number of implants (0.80) and implant sites (0.81). It was much lower for implant sizes (0.51) and did not reach significance for anatomical complications (0.09). CONCLUSIONS: Reformatted 2D-CT is reliable for the pre-operative assessment of the number and sites of implants in the jaws. It is less predictable for the implant size needed and poor for anatomical complications.     

Fixation, polyethylene wear, and pelvic osteolysis in primary total hip replacement

A multicenter retrospective review was performed analyzing 1081 primary total hip replacements in 944 patients using the Harris Galante-I cementless acetabular component with screw fixation. All patients were followed up for a minimum of 5 years with a mean followup of 81 months. Linear polyethylene wear averaged 0.11 mm/year (range, 0-0.86 mm/year). Pelvic osteolysis was seen in 25 patients (2.3%). Migration of the acetabular component was seen in four hips. A subgroup of patients was reanalyzed at a minimum followup of 10 years. The mean linear polyethylene wear rate remained 0.11 mm/year. In this group, only one socket had migrated. There was an association between wear rate and age. On average, younger patients had higher wear rates. The risk for having pelvic osteolysis develop and the need for revision surgery also was age-related. Twenty-two percent of hip replacements (15 hips) in patients younger than 50 years of age at the time of their index operation had pelvic osteolysis develop. In contrast, for patients older than 50 years of age at the time of surgery only 7.8% (eight hips) had osteolysis of the pelvis develop. For patients older than 70 years of age at the time of primary total hip replacement, none had pelvic osteolysis develop.     

The fate of stable cemented acetabular components retained during revision of a femoral component of a total hip arthroplasty

BACKGROUND: The decision as to whether to revise or retain a well fixed cemented acetabular component during revision of a femoral component is especially difficult; the rate of loosening of cemented acetabular components is high, whereas that of porous-coated acetabular components inserted during revision is low. However, removal of a well fixed cemented acetabular component can result in increased operative morbidity and cost and in loss of acetabular bone. Data that can be used to predict the long-term survival of retained well fixed cemented acetabular components are therefore needed. METHODS: We studied the five to thirteen-year clinical and radiographic results in a group of twenty-six consecutive patients in whom a well fixed cemented acetabular component had been retained during revision of a femoral component. Typical demographic data on the patients and information about the components were recorded, and the cemented acetabular components were graded as A through F, according to the system of Ranawat et al., at the time of the femoral revision. The average duration of follow-up was 8.4 years (range, 5.0 to 12.7 years). No patient was lost to follow-up. RESULTS: Four acetabular components (15 percent) had progressive radiolucency (at forty-eight, forty-eight, fifty-nine, and seventy-five months after the femoral revision) and were considered radiographically loose despite not being associated with symptoms. All four components were graded as either E or F at the time that they were retained during the femoral revision; radiographic loosening was significantly related to these two grades (p < 0.01). No acetabular component with a grade of A, B, C, or D loosened. The components that loosened had been in vivo for a relatively shorter, as opposed to longer, duration before the femoral revision compared with the components that did not loosen (p < 0.05). CONCLUSIONS: Retention of the well fixed cemented acetabular components was associated with good clinical results but with a 15 percent rate of loosening. Revision of a cemented acetabular component solely on the basis of the duration that it was in vivo or whether a previous revision had been done does not appear to be warranted. Our findings suggest that acetabular components with a grade of A, B, C, or D at the time of a femoral revision may be retained, as these components continued to function at the time of the five to thirteen-year follow-up in the current study.     

Experimental microgyri disrupt the barrel field pattern in rat somatosensory cortex

Transcranial freeze lesions in neonatal rat pups produce microgyri and adjacent epileptogenic regions of neocortex that can be used to model human polymicrogyria. The hypothesis that the presence of microgyri is associated with abnormal cortical organization occurring within as well as adjacent to the microgyri was tested by creating microgyri within the face representation of somatosensory cortex. Microgyri were associated with a widespread disruption of the stereotypic whisker barrel field pattern delineated with cytochrome oxidase (CO) staining. CO-stained patches resembling barrel hollows were absent within the microgyrus, and were abnormally shaped and distributed outside of the microgyrus. Adjacent Nissl- or acetylcholinesterase-stained sections demonstrated that both cell clusters and thalamocortical afferents contributed to the abnormally organized paramicrogyral zone identified in CO-stained sections. Field potential recordings showed that this region of heavy CO staining corresponded to the epileptogenic zone adjacent to the microgyrus. Results support our hypothesis that the epileptogenic paramicrogyral zone develops an abnormal organization of cell clusters and thalamocortical projections that could contribute to epileptogenesis in the paramicrogyral zone.     

Influence of traumatic grief on suicidal ideation among young adults

OBJECTIVE: The purpose of this study was to examine the influence of traumatic grief on suicidal ideation. METHOD: The Beck-Kovacs Scale for Suicidal Ideation was administered to 76 young adult friends of suicide victims. RESULTS: Traumatic grief was associated with a 5.08 times greater likelihood of suicidal ideation, after control for depression. Comorbid traumatic grief and depression were not associated with a greater likelihood of suicidal ideation. CONCLUSIONS: Syndromal traumatic grief heightens vulnerability to suicidal ideation.