Predicting the Influence of Streamflow on Migration and Spawning of a Threatened Diadromous Fish, the Australian Grayling Prototroctes Maraena.

The development of effective strategies to restore the biological functioning of aquatic ecosystems with altered flow regimes requires a detailed understanding of flow-ecology requirements, which is unfortunately lacking in many cases. By understanding the flow conditions required to initiate critical life history events such as migration and spawning, it is possible to mitigate the threats posed by regulated river flow by providing targeted environmental flow releases from impoundments. In this study, we examined the influence of hydrological variables (e.g., flow magnitude), temporal variables (e.g., day of year) and spatial variables (e.g., longitudinal position of fish) on two key life history events (migration to spawning grounds and spawning activity) for a threatened diadromous fish (Australian grayling Prototroctes maraena) using data collected from 2008 to 2015 in the Bunyip-Tarago river system in Victoria. Our analyses revealed that flow changes act as a cue to downstream migration, but movement responses differed spatially: fish in the upper catchment showed a more specific requirement for rising discharge to initiate migration than fish in the lower catchment. Egg concentrations peaked in May when weekly flows increased relative to the median flow during a given spawning period. This information has recently been incorporated into the development of targeted environmental flows to facilitate migration and spawning by Australian grayling in the Bunyip-Tarago river system and other coastal systems in Victoria.

Breast cancer mortality and diet in the United States.

Internationally, breast cancer mortality is correlated with intestinal lactase sufficiency and dairy product consumption beyond childhood. Within the United States, age-adjusted breast cancer mortality is positively associated with consumption of milk, butter, and total milk fat in regional analyses, and it is associated with milk demand in state-based analyses. Breast cancer mortality is also positively associated with demand for total calories, protein, fat, beef, and table fats (butter and margarine), and it is negatively associated with egg demand. Only the associations with milk and egg demand, however, survive when the Southern states are eliminated from the analyses or when either age of first marriage or income is controlled. The associations with milk and egg demand persist despite multiple controls for other dietary and demographic variables, although the association with milk demand loses statistical significance in some second- and third-order partial correlations. The inverse correlation with egg demand is strong but in the opposite direction from what might have been expected from previous studies. The correlation between milk demand and breast cancer mortality, although weaker, is consistent with results from previous studies, and it suggests a possible special role for dairy products in the etiology of breast cancer.

Decreased insulin secretion and increased insulin resistance are independently related to the 7-year risk of NIDDM in Mexican-Americans.

The relative importance of insulin resistance and abnormal insulin secretion as risk factors for the development of non-insulin-dependent diabetes mellitus (NIDDM) is still controversial. Few data are available on insulin secretion as a risk factor for the development of NIDDM, especially in subjects with normal glucose tolerance. We examined the relation of fasting insulin (as a marker of insulin resistance) and the ratio of change in insulin to change in glucose during the first 30 min after glucose ingestion (delta I30/delta G30) (as a marker of insulin secretion) as predictors of the 7-year development of NIDDM in 714 initially nondiabetic Mexican-Americans. NIDDM developed in 99 subjects. The relative risk of NIDDM increased with higher quartiles of fasting insulin (quartile 1 [low], 1.0; quartile 2, 1.5; quartile 3, 2.0; and quartile 4 [high], 3.7; P < 0.0001) and lower delta I30/delta G30 (quartile 1 [low], 6.9; quartile 2, 1.9; quartile 3, 1.1; quartile 4 [high], 1.0; P < 0.001). Subjects with both increased fasting insulin and decreased delta I30/delta G30 had independent increases in NIDDM incidence (P < 0.001). Further, when we stratified subjects by baseline glucose tolerance, both increased fasting insulin and decreased delta I30/delta G30 significantly predicted NIDDM in subjects with both impaired and normal glucose tolerance at baseline. We conclude that both decreased insulin secretion (as assessed by low delta I30/delta G30) and increased insulin resistance (as assessed by fasting insulin) predict the development of NIDDM in Mexican-Americans, a group previously characterized as having hyperinsulinemia and insulin resistance.(ABSTRACT TRUNCATED AT 250 WORDS)

Prevalence of diabetes in Mexican Americans. Relationship to percent of gene pool derived from native American sources.

We have estimated the prevalence of non-insulin-dependent diabetes mellitus (NIDDM) in Mexican Americans and Anglos in three San Antonio neighborhoods. The age-adjusted NIDDM rates (both sexes pooled) for Mexican Americans were 14.5%, 10%, and 5% for residents of a low-income barrio, a middle-income transitional neighborhood, and a high-income suburb, respectively. In Mexican American women, though not in men, obesity also declined from barrio to suburbs. We have previously shown, however, that, although obesity is an important cause of NIDDM in Mexican Americans, there is a two- to fourfold excess in the rate of NIDDM in this ethnic group over and above that which can be attributed to obesity. We therefore speculated that genetic factors might also contribute to excess NIDDM in this ethnic group. The percent native American admixture of Mexican Americans as estimated from skin color measurements was 46% in the barrio, 27% in the transitional neighborhood, and 18% in the suburbs. The NIDDM rates in Mexican Americans thus paralleled the proportion of native American genes. Furthermore, the San Antonio Mexican American rates were intermediate between the NIDDM rates of "full-blooded" Pima Indians (49.9%), who presumably have close to 100% native American genes, and the San Antonio Anglo population (3.0%) and the predominantly Anglo HANES II population (3.1%), both of which presumably have few if any native American genes. The association of genetic admixture with NIDDM rates suggests that much of the epidemic of NIDDM in Mexican Americans is confined to that part of the population with a substantial native American heritage.

Metabolic precursors of hypertension. The San Antonio Heart Study.

BACKGROUND: The relation of possible metabolic precursors (especially insulin resistance) to hypertension has been controversial. In addition, these associations may differ by level of obesity or ethnicity. METHODS: We followed up 1039 initially nondiabetic, nonhypertensive subjects from the San Antonio Heart Study for 7 years. RESULTS: Hypertension developed in 93 subjects. Age, body mass index, waist-to-hip ratio, and fasting insulin and triglyceride levels predicted the development of hypertension in univariate analyses. After adjustment for age, body mass index, waist-to-hip ratio, gender, ethnicity, and fasting glucose levels, higher levels of triglyceride and fasting insulin predicted the development of hypertension. Body mass index and fasting insulin and triglyceride levels predicted the development of hypertension in Mexican Americans and non-Hispanic whites. In addition, fasting insulin levels predicted the development of hypertension in lean and obese subjects. Increased insulin secretion (as judged by the 30-minute insulin increment) on an oral glucose tolerance test also predicted the development of hypertension. CONCLUSIONS: A cluster of atherogenic changes may precede the development of hypertension, and increased fasting insulin concentration predicts hypertension in important subgroups of subjects.

Rapid rise in the incidence of type 2 diabetes from 1987 to 1996: results from the San Antonio Heart Study.

BACKGROUND: The prevalence of type 2 diabetes has increased in the early part of the 20th century, particularly in developing countries. There is now evidence that the prevalence also continues to increase in developed countries, including the United States. However, it is unknown whether this increase is due to a rise in the incidence of diabetes or to decreasing diabetic mortality or both. METHODS: Participants in the San Antonio Heart Study, who were nondiabetic at baseline and who returned for a 7- to 8-year follow-up examination, were examined for secular trends in the incidence of type 2 diabetes. Risk factors for diabetes, such as obesity, were also examined. Patients were enrolled in the San Antonio Heart Study from 1979 to 1988 and 7- to 8-year incidence of diabetes was determined from 1987 to 1996. RESULTS: A significant secular trend in the 7- to 8-year incidence of type 2 diabetes was observed in Mexican Americans (5.7% for participants enrolled in 1979 to 15.7% for participants enrolled in 1988). In non-Hispanic whites, the incidence increased from 2.6% for participants enrolled in 1980 to 9.4% for participants enrolled in 1988 (P = .07) . After adjusting for age and sex, the secular trend remained significant in Mexican Americans and borderline significant in non-Hispanic whites. This indicates that between 1987 and 1996 the 7- to 8-year incidence of type 2 diabetes approximately tripled in both ethnic groups. The overall secular trend also remained significant after adjusting for additional risk factors for diabetes, such as obesity. A rising secular trend in obesity was also observed. CONCLUSIONS: There has been a significant increasing secular trend in the incidence of type 2 diabetes in Mexican Americans and a borderline significant trend in non-Hispanic whites participating in the San Antonio Heart Study. Unlike other cardiovascular risk factors such as lipid levels, cigarette smoking, and blood pressure, which are either declining or under progressively better medical management and control, and unlike cardiovascular mortality, which is also declining, obesity and type 2 diabetes are exhibiting increasing trends. Thus, obesity and diabetes could easily become the preeminent US public health problem.

Effects of diabetes and level of glycemia on all-cause and cardiovascular mortality. The San Antonio Heart Study.

OBJECTIVE: Although the level of hyperglycemia is clearly a risk factor for microvascular complications in diabetic patients, its role in macrovascular complications remains controversial. We followed 4,875 subjects (65% Mexican-American) for 7-8 years to investigate the effects of diabetes and hyperglycemia on all-cause and cardiovascular disease (CVD) mortality. These end points were also analyzed according to quartiles of baseline fasting plasma glucose among diabetic participants. RESEARCH DESIGN AND METHODS: The Cox proportional hazards model was used to estimate the relative risks (RRs) for all-cause and CVD mortality. RESULTS: Diabetes was significantly associated with increased all-cause mortality (RR [95% CI] = 2.1 [1.3-3.5] in men; 3.2 [1.9-5.4] in women) and increased CVD mortality (3.2 [1.4-7.1] in men; 8.5 [2.8-25.2] in women). Among diabetic subjects, those in quartile 4 had a 4.2-fold greater risk of all-cause mortality (P < 0.001) and a 4.7-fold greater risk of CVD mortality (P = 0.01) than those in quartiles 1 and 2 combined. After further adjustment for other potential risk factors, subjects in quartile 4 had a 4.9-fold greater risk of all-cause mortality and a 4.9-fold greater risk of CVD mortality than those in quartiles 1 and 2. In addition, hypertension, current smoking, and cholesterol > 6.2 mmol/l were significant predictors of CVD mortality using Cox models. CONCLUSIONS: We conclude that diabetes is a predictor of both all-cause and CVD mortality in the general population and that both hyperglycemia and common CVD risk factors are important predictors of all-cause and CVD mortality in diabetic subjects.

Reversion from type 2 diabetes to nondiabetic status. Influence of the 1997 American Diabetes Association criteria.

OBJECTIVE: To determine the incidence and the rate of reversion of type 2 diabetes to a nondiabetic status in the 7- to 8-year follow-up of the San Antonio Heart Study, and to determine the influence of the recent 1997 American Diabetes Association (ADA) criteria for diabetes on these rates. Individuals who revert have been problematic for those developing criteria for the diagnosis of type 2 diabetes. Few studies have addressed this issue using 1979 National Diabetes Data Group/1980 World Health Organization (WHO) criteria. RESEARCH DESIGN AND METHODS: We studied 3,682 Mexican-American and non-Hispanic white men and nonpregnant women who completed both the baseline and follow-up examination of the San Antonio Heart Study. Incidence and reversion rates were calculated using both the 1980 WHO and the 1997 ADA criteria. Risk factors for reversion were identified, and the best fitting model using multiple logistic regression was determined using both the 1980 WHO and the 1997 ADA criteria. RESULTS: Using the 1997 ADA criteria, the age-adjusted incidences of type 2 diabetes for Mexican-American men and women were 10.8 and 12.2%, respectively. For non-Hispanic white men and women, the age-adjusted incidence rates were 5.5 and 5.1%, respectively. Similar age-adjusted incidences were recorded using the 1980 WHO criteria. The reversion rate for individuals with type 2 diabetes was 11.5% using the 1980 WHO criteria and 12.5% using the 1997 ADA criteria. These rates were not significantly different. Numerous risk factors for reversion were identified. The best fitting model, after controlling for age, sex, and ethnicity, included baseline 2-h glucose level, baseline HDL cholesterol, and previous diagnosis of diabetes. The models were the same for both the 1980 WHO and the 1997 ADA criteria. CONCLUSIONS: There was no significant difference in the incidence or the reversion rates for diabetic subjects using either 1980 WHO or 1997 ADA criteria. In addition, the risk factors for reversion were very similar using either set of criteria. The revision of the ADA criteria did not have a significant influence on reversion in this study.

Mechanical filtering of sound in the inner ear.

We have studied the distortion generated by the cochlea to gain insight into the mechanisms responsible for the sharp tuning or 'frequency selectivity' of the inner ear. We used two stimulating tones of moderate intensity which are progressively separated in frequency, and measured the ear canal cubic distortion components which are generated as a consequence of the stimulus interaction in the cochlea. We inferred that the distortion is generated from the frequency region of the higher of the two stimulus tones and that it is then band-pass filtered by a structure which is tuned to a frequency just over half an octave below that of the high-frequency tone. We suggest that the structure responsible for this band-pass filtering is the tectorial membrane, and we conclude that our results support theories of cochlear mechanics in which resonances due to the tectorial membrane interact with those of the basilar membrane to enhance the frequency selectivity of the inner ear.

Giant bilateral xanthogranulomas in a child: case report.

Symptomatic xanthogranulomas are rare lesions that most commonly occur in adults. A case of giant bilateral xanthogranulomas in a 6-year-old boy, who remains without tumor recurrence 9 years after resection, is presented. The operative management of these unusually large lesions is discussed. The pathogenesis of xanthogranulomas is reviewed as it relates to the presentation of these lesions in the pediatric population.

Dividing attention within and between hemispheres: testing a multiple resources approach to limited-capacity information processing.

Two experiments tested the limiting case of a multiple resources approach to resource allocation in information processing. In this framework, the left and right hemispheres are assumed to have separate, limited-capacity pools of undifferentiated resources that are not mutually accessible, so that tasks can overlap in their demand for these resources either completely, partially, or not at all. We tested all three degrees of overlap in demand for left hemisphere supplies, using dual-task methodology in which subjects were induced to pay different amounts of attention to each task. Experiment 1 compared complete and partial overlap by combining a verbal memory load with a task in which subjects named nonsense syllables briefly presented to either the left or right visual field (LVF and RVF, respectively). Experiment 2 compared complete versus no overlap by using the same verbal memory load combined with a laterally presented same-different judgment task that did not require a spoken response. Decrements from single-task performance were always more severe when the visual field task stimulus was presented to the RVF. Further, subjects in Experiment 1 were able to trade performance between tasks on both LVF and RVF trials because there was always at least some overlap in left hemisphere demand. In Experiment 2, performance trade-offs were observed on RVF (complete overlap) trials, but not on LVF trials, where no overlap in demand existed. These results contradict a single-capacity model, but they support the idea that the hemispheres' resource supplies are independent and have implications for both cerebral specialization and divided attention issues.

Responses to training in cross-country skiers.

PURPOSE: This study evaluated whether cross-country skiers who did not respond positively to a training program consisting of high volume and low intensity would improve if high-intensity training volume was doubled during a subsequent training year. METHODS: During the first year of the study, cross-country skiers (N = 14) were evaluated for VO2max, VO2threshold, lactate response, max arm power, and competitive results after a standard training program. During the second year, the athletes were divided into a control group (athletes who had responded well to the training) and a treatment group (athletes who had responded poorly to the training). The control group (N = 7) repeated the previous year's training program. The treatment group (N = 7) was given a modified training program which increased high-intensity training time as a percentage of total training from < 17% to > 35% and decreased low-intensity training volume 22%. RESULTS: The treatment group, using the high-intensity training program, demonstrated significantly improved VO2max, VO2threshold, max arm power, and competitive results (P < 0.05). CONCLUSIONS: Increased volume of high-intensity training may improve competitive results in cross-country skiers who fail to respond to increased volume of low-intensity training.

Validity and reliability of combining three methods to determine ventilatory threshold.

PURPOSE: This research was undertaken to validate a combination of methodologies to determine ventilatory threshold (VT). METHODS: Three methods were used individually and then combined to determine VT as follows: 1) ventilatory equivalencies, 2) excess CO2 production, and 3) a modified V-slope method. Three groups of participants-endurance athletes (N = 132), healthy, aerobically active adults (N = 31), and healthy, sedentary/low-active adults (N = 22)-were independently evaluated for VT and compared with the criterion standard lactate threshold (LT) defined as the first rise in blood lactate with increasing intensity of exercise. RESULTS: VT and LT were significantly correlated using the combined VT method within each study group (r = 0.98, 0.97, and 0.95, respectively; P < 0.001). Mean VO2 values at VT and LT were not significantly different between the three groups (P > 0.20). The combined method improved the determination rate of VT and reduced the standard deviation of the LT - VT difference by 80-170% over the individual methods. During test-retest procedures VO2lt and VO2vt determined by the combined method met criteria demonstrating further reliability. CONCLUSION: The combined method to determine VT is valid and reliable across a wide fitness range in healthy individuals and improves the determination rate and accuracy of VT determination over the use of single methods.

Familial resemblance in ventilatory threshold: the HERITAGE Family Study.

PURPOSE: This study investigates the familial resemblance of VO2 at the ventilatory threshold (VO2vt) from 199 nuclear families (100 White and 99 Black) participating in the HERITAGE Family Study. METHODS: VO2vt (mL x min(-1)) was determined in the sedentary state and again after 20 wk of aerobic cycle ergometer exercise training in 339 individuals (131 parents and 228 of their offspring), aged between 17 and 65 yr. VO2vt was adjusted for weight, age, fat mass, and fat-free mass by using regression methods. RESULTS: There was evidence for significant familial resemblance in the sedentary state for VO2vt (maximal heritability = 58% in White and 54% in Black families) and VO2vt/VO2max (maximal heritability = 38% in White and 39% in Black families). Spouse, sibling, and parent-offspring relationships for VO2vt were significant at baseline, suggesting that both genetic and shared environmental factors may contribute to the familial resemblance in the sedentary state. There was a moderate familial component in the response of VO2vt to aerobic exercise training in Whites (22%) and a larger component in Blacks (51%). In Blacks, the familial effect for VO2vt/VO2max appeared to be accounted for by fat and fat-free mass. CONCLUSION: These results show a strong familial contribution to VO2vt in the sedentary state and to the response of VO2vt to aerobic exercise training.

Physiological effects of technique and rolling resistance in uphill roller skiing.

OBJECTIVE: The double pole technique (DP) has been shown to be more economical than the V1 skate technique (V1 ) on flat terrain. The objective of the present study was to compare these two techniques during uphill roller skiing. In addition, the physiological effects of changing roller ski rolling resistance was examined for V1. METHODS: Five female and five male competitive cross-country skiers roller skied 4-min bouts on a 5.2% incline while physiological measurements were made. RESULTS: Oxygen uptake (VO2) values averaged 8% greater (P = 0.0004) with V1, whereas rating of perceived exertion (RPE) and blood lactate concentrations were higher (P < or = 0.002) with DP. Doubling the dynamic friction coefficient of the roller skis, which increased external power output by 16-17%, resulted in VO2 values with V1 that averaged 13% higher (P = 0.0006). This magnitude of change in roller ski rolling resistance did not cause a statistical change in the relationship of VO2 with RPE. CONCLUSIONS: These findings suggest that 1) grade has little effect on relative economies of DP and V1, possibly because of a lower effectiveness of force application with V1 when going uphill, and 2) large differences in roller ski rolling resistance should have no effect on the cardiovascular training adaptations that result from uphill roller skiing with V1.

Continuing medical education versus clinic-based STD and HIV education interventions for primary care service providers: replication and extension.

An evaluation of a 2-day sexually transmitted disease (STD) and HIV and AIDS curriculum for primary care providers is presented which compares large scale continuing medical education (CME) conferences with smaller clinic workshop (CW) models with regard to short-term (2-month) and long-term (10-month) program effects on STD and HIV knowledge, attitudes toward risk assessment, and frequency of both STD diagnosis and STD and HIV risk counseling. Data from interventions held in San Antonio, Texas (328 CME; 95 CW) replicate and extend earlier findings from a preliminary intervention, indicating nonsignificant CME-CW differences and dramatic and long-lasting gains from baseline among those with lower knowledge and experience levels preintervention. Similar program effect magnitudes were found for attitude and practice dimensions at 2 months postintervention, with the strongest consistent short and long-term program effects observed for STD and HIV knowledge among service providers.

Substrate utilization during arm and leg exercise relative to the ventilatory threshold in men.

BACKGROUND: The purpose of this study was to determine variations in substrate utilization in men during arm and leg exercise at 70 and 90% of mode specific ventilatory threshold (Tvent). METHODS: Ten males served as subjects. Limb total and muscle volumes were estimated in the right arm and leg with anthropometry. Ventilatory equivalence, excess CO2, and modified V-slope methods were used to determine Tvent. Subjects performed 15 min of exercise at 70 and 90%Tvent arm cranking (AC) exercise, and 70 and 90%Tvent leg cycling (LC) exercise. RESULTS: VO2, VE, and HR were higher during LC exercise at both intensities. However, arm and leg RPE were not different at 70 and 90%Tvent. There were no significant differences between modes at 70%Tvent in relative carbohydrate use (54.5+/-9.5 and 57.8+/-8.2% for AC and LC, respectively) and relative fat oxidation (45.5+/-9.5 and 42.2+/-8.2% for AC and LC, respectively). However, at 90%Tvent, relative carbohydrate oxidation was significantly higher during AC versus LC exercise (75.4+/-10.6 versus 68.6+/-9.0%, p<0.05). Energy expenditure (total kJ x min(-1) was significantly lower during AC exercise (14.5+/-2.9 and 18.4+/-3.4 for the 70 and 90%Tvent, respectively) versus LC exercise (27.1+/-3.3 and 34.8+/-4.1 for the 70 and 90%Tvent, respectively; p<0.05). CONCLUSIONS: These results indicate that substrate use during AC exercise is similar to LC exercise at 70%Tvent. However, as the exercise intensity increases, the smaller arm musculature becomes more dependent on carbohydrate utilization compared to the legs.

Improvement in upper extremity function and trunk control after selective posterior rhizotomy.

Selective posterior rhizotomy is being increasingly used in the treatment of spasticity associated with cerebral palsy. Anecdotal reports in the literature note that this procedure results in improved upper extremity function and trunk control. We present a systematic analysis of the results of selective posterior rhizotomy performed on patients with cerebral palsy at Santa Rosa Children's Hospital. Patients were video-taped before surgery and one year postoperatively. These videos were reviewed blind by an occupational therapist who graded patients' performance on three tasks: assumption of side sitting, maintenance of side sitting, and block building. Statistically significant improvements were noted in all three categories with p values of .0003, .0001, and .0044 respectively. These results support the anecdotal reports of improvement in upper extremity function and trunk control with selective posterior rhizotomy.

Caring: commitment to excellence or condemnation to conformity?

The art of caring to alleviate illness and to promote health is nursing's unique commitment to society and the health-care industry. How this practice is implemented dictates the success or failure of prescribed strategies. In addition, the way in which caring is implemented defines emotional maturity on both a personal and professional level. Several goals to rehabilitate the psychologically codependent person include: Developing an awareness of the origins of codependency and how early family experiences affect subsequent behavior and beliefs about oneself; Identifying the personal price and payoffs for continuing codependent behaviors; The ability to openly express personal needs, wishes, feelings, and opinions while respecting the rights of others; Learning to discriminate between loving/caring and the destructive control of codependency; and The ability to take responsibility for another rather than being responsible to another. Codependent behaviors are prevalent within professional nursing practice, as evidenced by examples provided from three specialty areas in nursing and the fact that women (who are traditionally assigned the cultural role of caring) constitute the majority of professional nurses. Therefore, it is a professional challenge to each nurse to ascertain whether practices are functional or dysfunctional: is the professional interpretation of caring a commitment to excellence or a condemnation to conformity in the unique delivery of health-care practice?

Selective posterior rhizotomy to treat spasticity associated with cerebral palsy: a critical review.

Selective posterior rhizotomy for the treatment of spasticity has become a widely used procedure. The historical evolution of this procedure is reviewed with an emphasis on the physiological basis for the procedure. The proper screening and selection criteria, perioperative management, operative technique, and postoperative therapy are discussed. Results from a series of 25 patients are reviewed. Ten of these patients were operated on for a goal of improved ease in caretaking and this was achieved. In seven patients, the goal was to improve independent functioning (ambulation was not considered possible) and this was achieved. Eight patients underwent the procedure to improve ambulation and this was achieved.