Birth weight and cognitive function in early adulthood: the Australian Aboriginal birth cohort study.

It has been suggested that in addition to genetic factors, fetal and post-natal growth influence cognition in early adulthood. However, most studies have been in developed populations, so it is unclear if the same findings would be seen in other, less developed, settings, and have used testing tools not applicable to an Australia Aboriginal population. This study investigated the relationships between cognitive function in early adulthood and birth weight and contemporary height. Simple reaction time (SRT), choice reaction time (CRT) and working memory (WM) were assessed using the CogState battery. A significant association was seen between birth weight and SRT in early adulthood, but not with the other two cognitive measures. Urban dwellers had significantly shorter SRT and CRT than their remote counterparts. Contemporary body mass index and maternal age were associated with CRT. Only fetal growth restriction was associated with WM, with greater WM in those with restricted growth. No associations were seen with contemporary height. These results suggest that fetal growth may be more important than the factors influencing post-natal growth in terms of cognition in early adulthood in this population, but that the associations may be inconsistent between cognitive outcomes. Further research is required to identify whether similar associations are seen in other, similar, populations and to assess why differences in cognitive outcome measures are seen.

Associations between oral health and height in an indigenous Australian birth cohort.

OBJECTIVE: Evidence suggests that taller individuals have better health than their shorter counterparts. This study aimed to test the hypothesis that shorter participants in wave-3 of the Aboriginal Birth Cohort (ABC) study, a prospective longitudinal investigation of Indigenous Australian individuals born 1987-1990 at an Australian regional hospital, would have more caries and periodontal disease experience than their taller counterparts. METHODS: Data were collected through oral clinical examinations, anthropometric measures and self-report questionnaires. The outcome variables were participants' caries (mean DMFT) and periodontal disease experience (moderate or severe periodontal disease as defined by the Centre for Disease Control), with height as an explanatory variable. Antecedent anthropometric, socio-demographic, sugar consumption frequency, dental behaviour and substance use variables were used as possible confounders. Linear regression was used in the analysis of caries experience, while adjusted prevalence ratios were used for prevalence of moderate or severe periodontal disease. RESULTS: Higher DMFT was found among participants in the shortest tertile (B=1.02, 95% CI=0.02-2.02) and those who consumed sweets every day or a few days a week (B=1.08, 95% CI=0.11-2.05), while lower DMFT was found among those owning a toothbrush (B=0.80, 95% CI=-0.22-1.82). Periodontal disease was positively associated with the shortest tertile (adjusted PR=1.39, 95% CI=0.96-1.82) and negatively associated with toothbrush ownership (adjusted PR=0.50, 95% CI=0.34-0.66). CONCLUSION: The hypothesis that shorter participants in wave-3 of the ABC study would have higher levels of caries and periodontal disease was confirmed.

Associations between area-level disadvantage and DMFT among a birth cohort of Indigenous Australians.

BACKGROUND: Individual-level factors influence DMFT, but little is known about the influence of community environment. This study examined associations between community-level influences and DMFT among a birth cohort of Indigenous Australians aged 16-20 years. METHODS: Data were collected as part of Wave 3 of the Aboriginal Birth Cohort study. Fifteen community areas were established and the sample comprised 442 individuals. The outcome variable was mean DMFT with explanatory variables including diet and community disadvantage (access to services, infrastructure and communications). Data were analysed using multilevel regression modelling. RESULTS: In a null model, 13.8% of the total variance in mean DMFT was between community areas, which increased to 14.3% after adjusting for gender, age and diet. Addition of the community disadvantage variable decreased the variance between areas by 4.8%, indicating that community disadvantage explained one-third of the area-level variance. Residents of under-resourced communities had significantly higher mean DMFT (ß = 3.86, 95% CI 0.02, 7.70) after adjusting for gender, age and diet. CONCLUSIONS: Living in under-resourced communities was associated with greater DMFT among this disadvantaged population, indicating that policies aiming to reduce oral health-related inequalities among vulnerable groups may benefit from taking into account factors external to individual-level influences.

A retrospective longitudinal study of caries development in an Australian Aboriginal birth cohort.

There are a limited number of longitudinal investigations that examine the progression of dental disease in an indigenous population. Dental examinations of a cohort of indigenous Australians born in Darwin (Australia) between 1987 and 1990 were conducted at ages 6-8 and 11-13 years as part of the Child Dental Health Survey, and 18-20 years as part of the longstanding prospective Aboriginal Birth Cohort (ABC) study. Data was available at all ages for 145 participants. The percent DMFT >0 increased from 17.2 to 44.1 to 81.4%, representing a linear trajectory, whereas mean DMFT increased from 0.3 to 1.0 to 5.6, representing an exponential trajectory. Both trends were significant. At age 18-20 years, the percent DMFT >0 among ABC study participants was 1.2 times that of their counterparts at a national level. The differences were more marked when dental caries severity was considered, with mean DMFT among 18- to 20-year-old ABC study participants being 1.7 times that of similarly aged adults at a national level. Most of this disparity was constituted by the decayed component, with ABC study participants having eight times the mean DT of their national-level counterparts. The findings indicate that Aboriginal young adults in this birth cohort experience a disproportionate amount of dental disease relative to their non-indigenous counterparts, and that this pattern is consistent across the life course.

Dental caries risk indicators among Australian Aboriginal young adults.

OBJECTIVES: To determine dental caries risk indicators among a birth cohort of Australian Aboriginal young adults (n=442). METHODS: Data were from the Aboriginal Birth Cohort study, a prospective longitudinal investigation of Aboriginal individuals born 1987-1990 at an Australian regional hospital. Models representing demographic, socioeconomic, behavioural, dental service utilization and clinical oral health variables were tested using multivariate regression. RESULTS: The percent DT>0 was 72.9 (95% CI 68.7-77.1), mean DT was 4.19 (95% CI 3.8-4.6), percent DMFT>0 was 77.4 (95% CI 73.5-81.3) and mean DMFT was 4.84 (95% CI 4.4-5.3). After controlling for other covariates, risk indicators for percent DT>0 included soft drink consumption every day or a few times a week (PR 1.25, 95% CI 1.08-1.45), not consuming milk every day or a few times a week (PR 1.16, 95% CI 1.04-1.30) and sweet consumption every day or a few times a week (PR 1.18, 95% CI 1.04-1.33). Risk indicators for mean DT included sweet consumption every day or a few times a week (B=1.14, 95% CI 0.27-2.02), nonownership of a toothbrush (B=0.91, 95% CI 0.10-1.87) and presence of plaque (B=2.46, 95% CI 0.96-3.96). Those with 4 + occupants in their house the previous night had 1.2 times the prevalence of having DMFT>0 than their counterparts with less household occupants (95% CI 1.01-1.49). Percent DMFT>0 was also associated with consumption of soft drink every day or a few times a week (PR 1.18, 95% CI 1.04-1.34) and consumption of sweets every day or a few times a week (PR 1.23, 95% CI 1.10-1.37). Mean DMFT was higher among those who consumed sweets every day or a few times a week (B = 0.13, 95% CI 0.05-0.22) and who had dental anxiety (B=0.10, 95% CI 0.01-0.19). CONCLUSIONS: In an Australian Aboriginal young adult cohort, risk indicators for dental caries included social determinants such as household size, dietary behaviours such as regular consumption of soft drink and sweets, dental behaviour such as nonownership of a toothbrush and dental anxiety.

Efficacy of a tart cherry juice blend in preventing the symptoms of muscle damage.

BACKGROUND: Numerous antioxidant and anti-inflammatory agents have been identified in tart cherries. OBJECTIVE: To test the efficacy of a tart cherry juice blend in preventing the symptoms of exercise induced muscle damage. METHODS: This was a randomised, placebo controlled, crossover design. Fourteen male college students drank 12 fl oz of a cherry juice blend or a placebo twice a day for eight consecutive days. A bout of eccentric elbow flexion contractions (2 x 20 maximum contractions) was performed on the fourth day of supplementation. Isometric elbow flexion strength, pain, muscle tenderness, and relaxed elbow angle were recorded before and for four days after the eccentric exercise. The protocol was repeated two weeks later with subjects who took the placebo initially, now taking the cherry juice (and vice versa). The opposite arm performed the eccentric exercise for the second bout to avoid the repeated bout protective effect. RESULTS: Strength loss and pain were significantly less in the cherry juice trial versus placebo (time by treatment: strength p<0.0001, pain p = 0.017). Relaxed elbow angle (time by treatment p = 0.85) and muscle tenderness (time by treatment p = 0.81) were not different between trials. CONCLUSIONS: These data show efficacy for this cherry juice in decreasing some of the symptoms of exercise induced muscle damage. Most notably, strength loss averaged over the four days after eccentric exercise was 22% with the placebo but only 4% with the cherry juice.

Force recovery after eccentric exercise in males and females.

In this study we investigated force loss and recovery after eccentric exercise, and further characterized profound losses in muscle function (n = 192 subjects--98 males, 94 females; population A). Maximal voluntary contractile force (MVC) was assessed before, immediately after, and at 36 and 132 h after eccentric exercise. Two groups were then established (A1 and A2). Group A1 demonstrated a > 70% reduction in MVC immediately after exercise, but were recovering at 132 h after exercise. These subjects performed a follow-up MVC 26 days later (n = 32). Group A2 demonstrated a > 70% reduction in MVC immediately post-exercise, but still exhibited a > 65% reduction in force at 132 h post-exercise; these subjects also performed a follow-up MVC every 7 days until full recovery was established (n = 9). In population A, there was a 57% reduction in MVC immediately post-exercise and a 67% recovery by 132 h post-exercise (P < 0.01), with no significant gender differences (P > 0.05). In group A1, although more females (two-thirds) showed large force losses after exercise, these females demonstrated greater %MVC recovery at 132 h post-exercise (59% vs 44%) and at 26 days post-exercise (93% vs 81%) compared to the males. In group A2, MVC recovery occurred between 33 and 47 days post-exercise. In conclusion, 21% of all subjects showed a delayed recovery in MVC after high-force eccentric exercise. Although there were no significant gender differences in force loss, a disproportionately larger number of females demonstrated force reductions of > 70%. However, their recovery of force was more rapid than that observed for the males who also demonstrated a > 70% force loss.

Effect of ketoprofen on muscle function and sEMG activity after eccentric exercise.

PURPOSE: This study examined whether ketoprofen, a nonsteroidal anti-inflammatory drug, attenuated muscle soreness (SOR), improved maximal isometric force (MIF) recovery, and/or altered myoelectric activity after high-force eccentric exercise. METHODS: 48 subjects were randomly assigned to one of four groups: CON: no exercise/no drug (N = 12); PLA: exercise + placebo (N = 12); TRT-100: exercise + 100 mg oral ketoprofen (N = 12); and TRT-25: exercise + 25 mg oral ketoprofen (N = 12). PLA, TRT-100, and TRT-25 were administered in a double-blind fashion. Baseline measurements of SOR, MIF, and surface electromyographic (EMG) amplitude were taken, and PLA, TRT-100, and TRT-25 performed 50 maximal eccentric contractions of the elbow flexors; 36 h later, subjects reporting moderate soreness were given ketoprofen or placebo and SOR measures were taken hourly for 8 h. EMG amplitude was assessed during MIF before dosing and again 8 h later and during submaximal contractions of 5%, 10%, and 20% of MIF before dosing and hourly for 8 h. RESULTS: Eccentric exercise increased myoelectric activity during submaximal force measurements in PLA, TRT-100, and TRT-25 in all conditions. Ketoprofen had no effect on reducing this increase in EMG activity. Ketoprofen attenuated perceived SOR (P < 0.05) and enhanced MIF recovery (P < 0.05) compared with placebo. TRT-100 and TRT-25 demonstrated 10% and 19% reductions in SOR, respectively, and 16% and 9% increases in MIF, respectively, whereas PLA demonstrated a 1% increase in SOR and 9% decrease in MIF over 8 h. CONCLUSION: Ketoprofen treatment after muscle damaging exercise reduces muscle soreness and improves force recovery.

Activity and immobilization after eccentric exercise: I. Recovery of muscle function.

PURPOSE: The purpose of the present study was to determine whether activity would affect the recovery of muscle function after high-force eccentric exercise of the elbow flexors. METHODS: Twenty-six male volunteers were randomly assigned to one of three groups for a 4-d treatment period: immobilization (N = 9), control (N = 8), and light exercise (N = 9). Relaxed arm angle (RANG), flexed arm angle (FANG), maximal isometric force (MIF), and perceived muscle soreness (SOR) were obtained for 3 consecutive days pre-exercise (baseline), immediately post-exercise, and for 8 consecutive days after the 4-d treatment period (recovery). During the treatment period, the immobilization group had their arm placed in a cast and supported in a sling at 90 degrees. The control group had no restriction of their arm activity. The light exercise group performed a daily exercise regimen of 50 biceps curls with a 5-lb dumbbell. RESULTS: All subjects showed a prolonged decrease in RANG, increase in FANG, loss in MIF, and increase in SOR in the days after eccentric exercise. During recovery, there was no significant interaction observed among groups over time in RANG (P > 0.05) or FANG (P > 0.05), but there was a significant interaction observed among groups over time in both MIF (P < 0.01) and SOR (P < 0.01). Recovery of MIF was facilitated by light exercise and immobilization, whereas recovery from SOR was facilitated by light exercise and delayed by immobilization. CONCLUSIONS: The recovery of MIF in both the light exercise and immobilization groups suggests that more than one mechanism may be involved in the recovery of isometric force after eccentric exercise.

Activity and immobilization after eccentric exercise: II. Serum CK.

PURPOSE: The purpose of the present study was to examine the effect of muscle activity level on serum creatine kinase (CK) activity after high-force eccentric exercise of the elbow flexors. METHODS: Twenty-six male volunteers were randomly assigned to one of three groups for a 4-d treatment period after exercise: immobilization (N = 9), control (N = 8), and light exercise (N = 9). During the treatment period, the immobilization group had their arm casted and supported in a sling at 90 degrees. The control group had no restriction of their arm activity. The light exercise group performed a daily exercise regimen of 50 biceps curls with a 5-lb dumbbell. Serum CK activity was obtained by venipuncture for three consecutive days before eccentric exercise and during the 4-d treatment period. To quantify activity of the arm, CSA (Computer Science and Applications, Inc.) activity-monitoring devices were worn. RESULTS: Serum CK measurements revealed that there was a significant group by time interaction in the analysis of variance (P < 0.05). Peak serum CK activity of the immobilized group (668 IU) was lower than either the control (4230 IU) or light exercise (2740 IU) group. During the treatment period, activity level among the three groups was significantly different from each other (P < 0.001): 529 counts x min(-1) for the immobilization group, 944 counts x min(-1) for the control group, and 1334 counts x min(-1) for the light exercise group. CONCLUSIONS: These results suggest that immobilization of exercised damaged muscle during recovery significantly blunted serum CK activity, which may be due to attenuated removal of CK from the muscle and/or decrease lymphatic transport.

Adverse events associated with eccentric exercise protocols: six case studies.

PURPOSE: Rhabdomyolysis is a condition characterized by muscle damage and degeneration of muscle cells after strenuous, overexertion exercise. Although the incidence of severe rhabdomyolysis is rare, this condition can be dangerous and even fatal. Eccentric exercise protocols are currently being used to induce and study mild forms of muscle damage. However, serious adverse events can occur in these laboratory investigations. The purpose of this report was to expose some of the adverse events resulting from performance of eccentric exercise protocols to study muscle damage in humans. METHODS: The following case studies involved an eccentric exercise protocol where two sets of 25 maximal eccentric actions of the elbow flexors were performed, separated by a 5-min rest period. RESULTS: Case reports are presented that reveal prolonged losses in the ability of the muscle to generate force lasting 43-47 d, extreme swelling of the exercised arm lasting several weeks, and greatly elevated serum creatine kinase levels. CONCLUSIONS: Although adverse events resulting from eccentric exercise are rare, our laboratory has observed a 3% incidence rate during the past year. Investigators should be knowledgeable of the sequelae of events that are associated with muscle damage after high-force eccentric exercise and take appropriate precautions.

Etiology of exercise-induced muscle damage.

Muscle damage is caused by strenuous and unaccustomed exercise, especially exercise involving eccentric muscle contractions, where muscles lengthen as they exert force. Damage can be observed both directly at the cellular level and indirectly from changes in various indices of muscle function. Several mechanisms have been offered to explain the etiology of the damage/repair process, including mechanical factors such as tension and strain, disturbances in calcium homeostasis, the inflammatory response, and the synthesis of stress proteins (heat shock proteins). Changes in muscle function following eccentric exercise have been observed at the cellular level as an impairment in the amount and action of transport proteins for glucose and lactate/H+, and at the systems level as an increase in muscle stiffness and a prolonged loss in the muscle's ability to generate force. This paper will briefly review factors involved in the damage/repair process and alterations in muscle function following eccentric exercise.

Animal models of spinal cord contusion injuries.

BACKGROUND AND PURPOSE: Traumatic spinal cord injury causes initial mechanical disruption of tissue, leading to a complex secondary sequence of pathophysiologic changes and neurologic impairment. These sequelae depend on the impact force delivered to the spinal cord at the time of injury. Successful clinical evaluation of the efficacy of any therapeutic regimen depends on the reliability and reproducibility of an experimental animal model. We describe a trauma device and the biomechanical parameters required to induce severe or moderate spinal cord contusion injury in cats and rats. METHODS: Recovery after injury was determined by behavioral, electrophysiologic, and histologic evaluations. RESULTS: Behavioral and electrophysiologic tests after injury clearly identified the experimental groups. A stable severe paraplegic state (defined as 6 months for cats and 8 weeks for rats), without evidence of behavioral or electrophysiologic recovery, was induced by a 65-Newton (N) load for cats and a 35-N load for rats. Moderate spinal cord contusion injury, from which cats and rats partially recovered after approximately 3 months and 4 weeks, respectively, was induced by a 45- and 25-N load, respectively. CONCLUSION: Use of these injury conditions provides reliable animal models for studies designed to evaluate potential therapeutic regimens for spinal cord injury.

Cross-validation of three jump power equations.

UNLABELLED: The vertical jump-and-reach score is used as a component in the estimation of peak mechanical power in two equations put forth by Lewis and Harman et al. PURPOSE: The purpose of the present study was to: 1) cross-validate the two equations using the vertical jump-and-reach test, 2) develop a more accurate equation from a large heterogeneous population, 3) analyze gender differences and jump protocols, and 4) assess Predicted Residual Sum of Squares (PRESS) as a cross-validation procedure. METHODS: One hundred eight college-age male and female athletes and nonathletes were tested on a force platform. They performed three maximal effort vertical jumps each of the squat jump (SJ) and countermovement jump (CMJ) while simultaneously performing the vertical jump-and-reach test. Regression analysis was used to predict peak power from body mass and vertical jump height. RESULTS: SJ data yielded a better power prediction equation than did CMJ data because of the greater variability in CMJ technique. The following equation was derived from SJ data: Peak Power (W) = 60.7x (jump height cm]) +45.3x(body mass [kg])-2055. This equation revealed greater accuracy than either the Lewis or previous Harman et al. equations and underestimated peak power by less than 1%, with a SEE of 355.0 W using SJ protocol. The use of one equation for both males and females resulted in only a slight (5% of power output) difference between genders. Using CMJ data in the SJ-derived equation resulted in only a 2.7% overestimation of peak power. Cross-validation of regression equations using PRESS reveals accurate and reliable R2 and SEE values. CONCLUSIONS: The SJ equation is a slightly more accurate equation than that derived from CMJ data. This equation should be used in the determination of peak power in place of the formulas developed by both Harman et al. and Lewis. Separate equations for males and females are unnecessary.

Diabetes patient education.

Not all medical practices are equipped to provide diabetes self-management training. Physicians can incorporate a team approach in their practice by establishing collaborative relationships with recognized diabetes education programs. The ADA's education recognition program has identified diabetes education programs that meet the National Standards for Diabetes Self-Management Education Programs. This list is available on the ADA's web site at http://www.diabetes.org/recognition and is printed twice a year in Diabetes Forecast. The National Certification Board for Diabetes Educators (NDEA) can provide a list of CDEs in your area. The South Carolina Model Diabetes Patient Education Program of DSC and SCDCP/DHEC is an excellent critical step towards obtaining ADA recognition.

Prevention of marital dysfunction: behavioral approaches and beyond.

Marital dysfunction is a significant problem in the U.S., with far-ranging effects on the mental health, physical health, and economic well-being of people who experience it. In addition, marital discord and divorce appear to have adverse effects on children. This review describes the historical roots of current prevention programs and critically reviews marriage preparation programs that have been examined in the peer-reviewed literature. The results of 13 studies suggest that behaviorally oriented, skills-based marriage preparation programs can lead to behavioral changes that may help prevent the emergence of marital dysfunction. Whereas there has been modest improvement in the methodology of the program evaluations, suggestions for continued improvements are made. Ways to enhance the effectiveness of marriage preparation programs using the principles of prevention are described.

Preparation of brain-derived neurotrophic factor- and neurotrophin-3-secreting Schwann cells by infection with a retroviral vector.

One reason that the central nervous system of adult mammals does not regenerate after injury is that neurotrophic factors are present only in low concentrations in these tissues. Recent studies have shown that the application of brain-derived neurotrophic factor (BDNF) and neurotrophin-3 (NT-3) acts to encourage the regrowth of motor and sensory fibers after spinal cord injury. Other studies have reported that the regrowth of axons after injury was enhanced by the implantation of Schwann cells, which normally secrete BDNF and NT-3. The purpose of the present study was to genetically modify Schwann cells to secrete increased amounts of BDNF or NT-3 by infection with a retroviral vector. Retroviral vectors were constructed by the ligation of BDNF or NT-3 cDNA to the LXSN vector. Viruses were generated from the plasmid forms of the vectors by transient transfection of PA317 amphotrophic retroviral packaging cells. Viruses were harvested and used to infect the human Schwann cell line designated NF-1T. Northern blot analysis of poly (A+) RNA prepared from Schwann cells that were infected with BDNF- or NT-3-containing virus showed the presence of BDNF or NT-3 mRNA. An enzyme-linked immunosorbent assay (ELISA) for BDNF and NT-3 was performed on media the cells were grown in, and on cellular extracts prepared from the BDNF- and NT-3-infected Schwann cells. The ELISA results demonstrated that the Schwann cells were secreting increased levels of immunologically active BDNF or NT-3. Immunocytochemical staining of these cells revealed the presence of these two neurotrophic factors located in perinuclear granules. These neurotrophic factor-secreting Schwann cells are currently being evaluated for their efficacy in the treatment of spinal cord injury.