Comparative analysis of thermal indices for modeling cold and heat stress in US dairy systems

Quantifying the impact of thermal stress on milk yields is essential to effectively manage present and future risks in dairy systems. Despite the existence of numerous heat indices designed to communicate stress thresholds, little information is available regarding the accuracy of different indices in estimating milk yield losses from both cold and heat stress at large spatio-temporal scales. To address this gap, we comparatively analyzed the performance of existing thermal indices in capturing US milk yield response to both cold and heat stress at the national scale. We selected four commonly used thermal indices: the Temperature and Humidity Index (THI), Black Globe Humidity Index (BGHI), Adjusted Temperature and Humidity Index (THIadj), and Comprehensive Climate Index (CCI). Using a statistical panel regression model with observational and reanalysis weather data from 1981-2020, we systematically compared the patterns of yield sensitivities and statistical performance of the four indices. We found that the US state-level milk yield variability was better explained by the THIadj and CCI, which combine the effects of temperature, humidity, wind, and solar radiation. Our analysis also reveals a continuous and nonlinear responses of milk yields to a range of cold to heat stress across all four indices. This implies that solely relying on fixed thresholds of these indices to model milk yield changes may be insufficient to capture cumulative thermal stress. Cold extremes reduced milk yields comparably to those impacted by heat extremes on the national scale. Additionally, we found large spatial variability in milk yield sensitivities, implying further limitations to the use of fixed thresholds across locations. Moreover, we found decreased yield sensitivity to thermal stress in the most recent two decades, suggesting adaptive changes in management to reduce weather-related risks.

A meta-analysis of the relationship between milk protein production and absorbed amino acids and digested energy in dairy cattle

Milk protein production is the largest draw on AA supplies for lactating dairy cattle. Prior NRC predictions of milk protein production have been absorbed protein (MP)-based and utilized a first-limiting nutrient concept to integrate the effects of energy and protein, which yielded poor accuracy and precision (root mean squared error (RMSE) > 21%). Using a meta-data set gathered, various alternative equation forms considering MP, absorbed total essential AA (EAA), absorbed individual EAA, and digested energy (DE) supplies as additive drivers of production were evaluated, and all were found to be superior in statistical performance to the first limitation approach (RMSE = 14-15%). Inclusion of DE intake and a quadratic term for MP or absorbed EAA supplies were found to be necessary to achieve intercept estimates (non-productive protein use) that were similar to the factorial estimates of NASEM. The partial linear slope for MP was found to be 0.409, which is consistent with the observed slope bias of -0.34g/g when a slope of 0.67 was used for MP efficiency in a first-limiting nutrient system. Replacement of MP with the supplies of individual absorbed EAA expressed in g/d and a common quadratic across the EAA resulted in unbiased predictions with improved statistical performance as compared with MP-based models. Based on Akaike's Information Criterion (AIC) and biological consistency, the best equations included absorbed His, Ile, Lys, Met, Thr, the non-essential AA, and individual DE intakes from fatty acids, neutral detergent fiber, residual organic matter, and starch. Several also contained a term for absorbed Leu. These equations generally had RMSE of 14.3% and a concordance correlations (CCC) of 0.76. Based on the common quadratic and individual linear terms, milk protein response plateaus were predicted at approximately 320 g/d of absorbed His, Ile, and Lys; 395 g/d of absorbed Thr; 550 g/d of absorbed Met; and 70 g/d of absorbed Leu. Therefore, responses to each except Leu are almost linear throughout the normal in vivo range. De-aggregation of the quadratic term and parsing to individual absorbed EAA resulted in non-biological estimates for several EAA indicating over-parameterization. Expression of the EAA as g/100 g of total absorbed EAA or as ratios of DE intake and using linear and quadratic terms for each EAA resulted in similar statistical performance, but the solutions had identifiability problems and several non-biological parameter estimates. The use of ratios also introduced nonlinearity in the independent variables which violates linear regression assumptions. Further screening of the global model using absorbed EAA expressed as g/d with a common quadratic using an all-models approach, and exhaustive cross-evaluation indicated the parameter estimates for body weight, all 4 DE terms, His, Ile, Lys, Met, and the common quadratic term were stable, while estimates for Leu and Thr were known with less certainty. Use of independent and additive terms and a quadratic expression in the equation results in variable efficiencies of conversion. The additivity also provides partial substitution among the nutrients. Both of these prevent establishment of fixed nutrient requirements in support of milk protein production.

Systematic review and meta-analysis of the methionine utilization efficiency in piglets receiving different methionine sources

Methionine (Met) is an essential amino acid that can be supplied in different chemical forms: DL-Met, L-Met, and OH-Met. This study aimed (i) to model and compare the utilization efficiency of Met for protein deposition (PD) from all sources and (ii) to determine the efficacy and efficiency of these three free Met sources in average daily gain (ADG) of post-weaning pigs fed at or below the Met requirement. A systematic review of the literature resulted in 1 898 papers being screened for title and abstract, with 24 papers meeting the inclusion criteria. The resulting database containing 208 treatment means was used. Prior to model development, the standardized ileal digestible (SID) Met requirements in percentage in the diet were determined using initial and final BW according to the NRC (2012). Data from piglets fed above the SID Met requirements were excluded from the database prior to statistical analysis. Linear mixed-effects regression models predicting ADG as a function of free Met source and SID methionine intake (Meti) or methionine + cysteine intake (Met + cysi) were used to evaluate the efficacy and efficiency of free Met source for weight gain. Moreover, Met retention was modeled assuming that 16% of ADG is deposited as PD, and that Met accounts for 2% of PD. Met utilization efficiency was calculated as Meti after maintenance divided by Met retained in PD. Met utilization efficiency was 77% for the basal diet, decreased (P < 0.01) as Meti increased, and was equal among the three free Met sources. The mixed-effects models showed no difference in ADG for three free Met sources evaluated (P > 0.05). However, the efficacy (ADG per unit of SID Meti) of free Met sources for weight gain differed between piglets fed L and DL-Met (P < 0.05), while there was no difference (P > 0.05) between piglets fed DL and OH-Met or OH and L-Met. On average, piglets fed L-Met gained 40.3 g/d more weight per unit of increase in SID Meti than those fed DL-Met (model 4; P = 0.05). The efficacy of free Met sources for ADG was also compared using SID Met + cysi as covariable. Piglets fed L- (+11.7 g/d; P = 0.02) or OH-Met (+11.5 g/d; P = 0.04) gained more weight per gram of SID Met + cysi compared to those fed DL-Met. In conclusion, although the efficacy of DL- and L-Met for ADG differed, the efficiency for PD of L-, DL-, and OH-Met were not different in piglets fed at or below Meti requirement.

Modeling the relationship between heat stress, feed intake, and day relative to calving in nonlactating dairy cows

Heat stress (HS) during the dry period can affect animal welfare, health, dry matter intake (DMI), and milk production in the subsequent lactation, which will negatively affect the profitability of dairy farms. In this study, the objective was to model the changes in DMI in pregnant nonlactating heat-stressed dairy cows with or without access to evaporative cooling systems. A database was built, composed of individual DMI records from 244 pregnant nonlactating dairy cows from an average -29.3 d (range: -42 to -21 d; SD: ±7.54 d) to -1 d relative to calving (DRC) and housed in environmental conditions in which temperature-humidity index (THI) ranged from 58.4 to 83.3, with or without access to evaporative cooling systems. Generalized additive mixed-effects models were used to describe the relationships of DMI with HS and DRC. Changes in DMI with the increase in THI and the progression of pregnancy in cows with or without evaporative cooling systems were estimated using differential equations. On average, cows housed in barns without evaporative cooling systems had a reduction in DMI of 1.30 kg/d and increased rectal temperature in 0.22°C in relation to those housed in barns with evaporative cooling systems. Dry matter intake decreased as THI increased, but the reduction was greater for noncooled cows as THI values increased. In addition, regardless of the THI, DMI started to decrease at -14 DRC for cooled cows, whereas for noncooled cows it already started at -30 DRC, relative to the previous days evaluated. The intensity of the reduction was lesser for cows that had access to evaporative cooling systems or were in the dry period in May to June as compared with those that were in the dry period in July to August or September to October. The models generated in this study, which include environmental variables, should lead to more accurate predictions of DMI during HS that can be used to formulate diets to meet the needs of the late pregnant cow because it is possible to predict changes in DMI as the heat load and DRC change. Such models are also expected to help dairy nutritionists to decide when and how to apply the dietary strategies available to attenuate the reductions in DMI with the intensity of HS and progression of pregnancy.

Modeling the effects of heat stress in animal performance and enteric methane emissions in lactating dairy cows

Heat stress (HS) negatively affects dry matter intake (DMI), milk yield (MY), feed efficiency (FE), and free water intake (FWI) in dairy cows, with detrimental consequences to animal welfare, health, and profitability of dairy farms. Absolute enteric methane (CH₄) emission, yield (CH₄/DMI), and intensity (CH₄/MY) may also be affected. Therefore, the goal of this study was to model the changes in dairy cow productivity, water intake, and absolute CH₄ emissions, yield, and intensity with the progression (days of exposure) of a cyclical HS period in lactating dairy cows. Heat stress was induced by increasing the average temperature by 15°C (from 19°C in the thermoneutral period to 34°C) while keeping relative humidity constant at 20% (temperature-humidity index peaks of approximately 83) in climate-controlled chambers for up to 20 d. A database composed of individual records (n = 1,675) of DMI and MY from 82 heat-stressed lactating dairy cows housed in environmental chambers from 6 studies was used. Free water intake was also estimated based on DMI, dry matter, crude protein, sodium, and potassium content of the diets, and ambient temperature. Absolute CH₄ emissions was estimated based on DMI, fatty acids, and dietary digestible neutral detergent fiber content of the diets. Generalized additive mixed-effects models were used to describe the relationships of DMI, MY, FE, and absolute CH₄ emissions, yield, and intensity with HS. Dry matter intake and absolute CH₄ emissions and yield reduced with the progression of HS up to 9 d, when it started to increase again up to 20 d. Milk yield and FE reduced with the progression of HS up to 20 d. Free water intake (kg/d) decreased during the exposure to HS mainly because of a reduction in DMI; however, when expressed in kg/kg of DMI it increased modestly. Methane intensity also reduced initially up to d 5 during HS exposure but then started to increase again following the DMI and MY pattern up to d 20. However, the reductions in CH₄ emissions (absolute, yield, and intensity) occurred at the expense of decreases in DMI, MY, and FE, which are not desirable. This study provides quantitative predictions of the changes in animal performance (DMI, MY, FE, FWI) and CH₄ emissions (absolute, yield, and intensity) with the progression of HS in lactating dairy cows. The models developed in this study could be used as a tool to help dairy nutritionists to decide when and how to adopt strategies to mitigate the negative effects of HS on animal health and performance and related environmental costs. Thus, more precise and accurate on-farm management decisions could be taken with the use of these models. However, application of the developed models outside of the ranges of temperature-humidity index and period of HS exposure included in this study is not recommended. Also, validation of predictive capacity of the models to predict CH₄ emissions and FWI using data from in vivo studies where these variables are measured in heat-stressed lactating dairy cows is required before these models can be used.

Far from urban areas: plastic uptake in fish populations of subtropical headwater streams

This study investigated the occurrence of plastic particles in the digestive tracts of fish from headwater streams in a human-thinly populated region of the subtropical Sinos River basin in southern Brazil. In total, 258 individuals from 17 species were collected using electric fishing. Thirty-eight percent (38%) of the specimens contained plastic particles. All of them were fibers, with a maximum count of 43 per individual. Plastic fibers were the fourth most abundant food category. Results showed that the uptake of these plastic particles was proportional to the number of ingested food items. Fiber counts in the guts correlated with the uptake of Trichoptera, which are invertebrates using plastic particles to construct their protective cases. No significant difference in plastic uptake was detected between benthic and water column fish. No evidence of bioaccumulation of plastic particles was found in the intestines. The distance from urban areas was not related to the number of ingested plastic particles, concluding that plastics are ubiquitous and available to biota, even in remote locations. The most probable source of these particles is residences close to the streams which discharge the sewage of washing machines without any treatment.

Post-COVID-19 tomographic abnormalities

BACKGROUND: The prevalence of persistent respiratory symptoms tends to be low in patients with a longer recovery time after COVID-19. However, some patients may present persistent pulmonary abnormalities.OBJECTIVE: To evaluate the prevalence of tomographic abnormalities 90 days after symptom onset in patients with COVID-19 and compare two chest high-resolution computed tomography (HRCT) analysis techniques.METHODS: A multicentre study of patients hospitalised with COVID-19 having oxygen saturation <93% on room air at hospital admission were evaluated using pulmonary function and HRCT scans 90 days after symptom onset. The images were evaluated by two thoracic radiologists, and were assessed using software that automatically quantified the extent of pulmonary abnormalities.RESULTS: Of the 91 patients included, 81% had at least one pulmonary lobe with abnormalities 90 days after discharge (84% were identified using the automated algorithm). Ground-glass opacities (76%) and parenchymal bands (65%) were the predominant abnormalities. Both chest HRCT technical assessments presented high sensitivity (95.9%) and positive predictive value (92%), with a statistically significant correlation at baseline (R = 0.80) and after 90 days (R = 0.36).CONCLUSION: The prevalence of pulmonary abnormalities on chest HRCT 90 days after symptom onset due to COVID-19 was high; both technical assessments can be used to analyse the images.

Combined Physical Training Increases Plasma Brain-Derived Neurotropic Factor Levels, But Not Irisin in People Living with HIV/AIDS

This study evaluated plasma levels of brain-derived neurotropic factor (BDNF), irisin, and lactate in people living with HIV/AIDS who completed a combined physical training program. Nineteen HIV+ participants (age: 39.60 ± 10.96 years; carrier time: 7.75 ± 7.88 years; time of ART: 6.41 ± 5.93 years) performed strength/aerobic training (combined physical training) in the same session for 8 weeks and levels of BDNF, irisin, and lactate were assessed. BDNF (pg/mL) was higher post-CPT (Pre: 1258.73 ± 372.30; Post: 1504.17 ± 322.30; p < 0.001). Irisin (ng/mL) showed no change (Pre: 115.61 ± 72.41; Post: 125.87 ± 81.14; p = 0.973). There was positive correlation between irisin and lactate (mmol/L) pre (r = 0.55, p = 0.04), and lactate values were higher in the group with the highest value of irisin (3.65 ± 0.69 × 2.82 ± 0.59, p = 0.02). Combined physical training results in increased basal BDNF in people living with HIV/AIDS, this finding suggests that increased concentration of BDNF may be associated with decreased chances of developing cognitive disorders or HIV-associated dementia. Further studies involving molecular mechanisms on this subject are necessary.

Predicting ruminally undegraded and microbial protein flows from the rumen

The objectives of the present work were (1) to identify the cause of the linear bias in predictions of rumen-undegradable protein (RUP) content of feeds, and devise methods to remove the bias from prediction equations, and (2) to further explore the impact of rumen-degradable protein (RDP) on microbial N (MiN) outflow from the rumen. The kinetic model used by NRC (2001), which is based on protein fractionation and rates of degradation (Kd) and passage (Kp), displays considerable slope bias (-0.30 kg/kg), indicating parameter or structural problems. Regressing Kp by feed class and a static adjustment factor for the in situ-derived Kd on observed RUP flows completely resolved the slope bias problem, and the model performed significantly better than models using unadjusted Kd and marker-based Kp. The Kd adjustment was 3.82%/h, which represents approximately a 50% increase in rates of degradation over the in situ values, indicating that in situ analyses severely underestimate true rates of protein degradation. The Kp for concentrate-derived protein was 5.83%/h, which was slightly less than the marker-predicted rate of 6.69%/h. However, the derived forage protein rate was 0.49%/h, which was considerably less than the marker-based rate of 5.07%/h. Compartmental analysis of data from a single study corroborated the regression analysis, indicating that a 25% reduction in the overall passage rate and an 87% increase in the rate of degradation were required to align ruminal N pool sizes and the extent of protein degradation with the observed data. Therefore, one must conclude that both the in situ-derived degradation rates and the marker-based particle passage rates are biased relative to protein passage and cannot be used directly to predict RUP outflow from the rumen. The effects of RDP supply on microbial nitrogen (MiN) flow were apparent when intakes of individual nutrients were offered but not when DM intake and individual nutrient concentrations were offered, due to collinearity problems. Microbial N flow from the rumen was found to be linearly related to ruminally degraded starch, ruminally degraded neutral detergent fiber (NDF), RDP, and forage NDF intakes; and quadratically related to residual OM intake. More complicated models containing 2- and 3-way interactions among nutrients were also supported by the data. Independent MiN responses to RDP, ruminally degraded starch, and ruminally degraded NDF aligned with the expected responses to each of those nutrients. Nonlinear representations of MiN were found to be inferior to the linear models. Despite using unbiased predictions of RUP and MiN as drivers of AA flows, predictions of Arg, His, Ile, and Lys flow exhibited linear slope bias relative to the observed data, indicating that representations of the AA composition of the proteins may be biased or the observed data are biased. This is an improvement over the NRC (2001) predictions, where bias adjustments were required for all of the essential AA. Despite the bias for 4 AA flows, the revised prediction system was a substantial improvement over the prior work.

Milk urea nitrogen variation explained by differences in urea transport into the gastrointestinal tract in lactating dairy cows

Milk urea nitrogen (MUN) and blood urea nitrogen are correlated with nitrogen balance and nitrogen excretion; however, there is also a genetic component to MUN concentrations that could be associated with differences in urea transport. It was hypothesized that a portion of the variation in MUN concentrations among cows is caused by variation in gastrointestinal and kidney urea clearance rates. Eight lactating cows with varying MUN concentrations while fed a common diet were infused with [¹⁵N¹⁵N]urea to determine urea N entry rate (UER), gastrointestinal entry rate, returned to ornithine cycle, urea N used for anabolism, urea N excretion in feces and urine. Urea clearance rates by the kidneys and gastrointestinal tract were calculated from isotopic enrichment of urea excretion in urine and gut entry rate, respectively, and plasma urea N concentrations (PUN). Over the course of the experiment, animals weighed an average of 506 ± 62 kg and produced 26.3 ± 4.39 kg of milk/d, with MUN concentrations ranging from 11.6 to 17.3 mg/dL (average of 14.9 ± 2.1 mg/dL). Plasma urea N was positively correlated with UER, urea N excretion in urine, and urea N used for anabolism. Plasma urea N and MUN were negatively correlated with gut clearance rates and ratio of gastrointestinal entry rate to UER. This relationship supports the hypothesis that differences in gut urea transport activity among animals causes variation in PUN and MUN concentrations, and that cows with high PUN and MUN are less efficient at recycling PUN to the gastrointestinal tract and thus may be more susceptible to ruminal N deficiencies when fed low RDP diets. Such biological variation in urea metabolism necessitates an adequate safety margin when setting regulations for maximal MUN levels as an indicator of herd N efficiency.

Habitual dietary intake and mediators of the inflammaging process in Brazilian older women

AIM

This study aimed to assess whether the habitual intake of macronutrients by older women associates with circulating levels of important inflammaging mediators by means of a cross-sectional design with 229 Brazilian elderly women.

METHODS

Laboratory tests determined serum IL1α, IL1β, IL6, IL8, IL10, IL12 and TNFα by specific immunoassays. Food records of three alternate days were decomposed into usual intake of carbohydrates, proteins and lipids (and fractions), as well as total energy value (TEV) per patient. Moreover, the study has identified and controlled results for metabolic conditions known to influence the inflammatory profile: hypercholesterolemia, hypertension and diabetes.

RESULTS AND DISCUSSION

Pearson's correlation test revealed that log10IL8 expressed a positive association with levels of saturated fatty acid (FA) (r = 0.173; p = 0.009) and total cholesterol intake (r = 0.223; p = 0.001). Similar analysis of the other mediators revealed no association with dietary intake.

CONCLUSION

Higher intakes of total cholesterol and saturated FA seem to correlate with increased serum IL8 levels, being a possible mechanism by which this pro-atherogenic intake pattern may increase the risk of age-related chronic diseases with important inflammatory contribution.

Relationship between sarcopenic obesity-related phenotypes and inflammatory markers in postmenopausal women

Ageing is associated with changes in body composition that may result in sarcopenic obesity (SO). Interleukin-6 (IL-6) and C-reactive protein (CRP) are important inflammatory markers related to ageing. SO has been examined as an important public health problem, but its association with inflammatory markers has yet to be investigated. The aim of this study was to investigate the association between SO-related phenotypes and inflammatory markers in postmenopausal women. A total of 130 women (66·7 ± 5·2 years) underwent body composition evaluation using dual-energy X-ray absorptiometry. Volunteers were classified according to a SO definition previously described in the literature. Waist circumference (WC) and handgrip strength (HG) were also measured. Blood samples were collected for CRP, tumour necrosis factor and IL-6 measurements. All the inflammatory markers were higher in SO individuals when compared to non-SO; however, only IL-6 reached statistical significance (median 3·34 versus 1·37 pg ml^-1 ; P<0·05). Also, CRP was significantly correlated (P<0·01) with body mass index (r_s  = 0·34), fat mass (FM; r_s  = 0·25) and WC (r_s  = 0·33). Similarly, IL-6 levels were significantly correlated (P<0·05) to age (r_s  = 0·19), FM (r_s  = 0·19) and WC (r_s  = 0·17). HG was found to be significantly reduced among subjects with higher IL-6 levels (P = 0·02). In summary, the combination of reduced muscle mass and excess body fat (i.e. SO) is associated with elevated inflammatory markers in postmenopausal women. Moreover, CRP and IL-6 are associated with SO-related phenotypes in this population.

Association of TNF -1031 C/C as a potential protection marker for leprosy development in Amazonas state patients, Brazil

Polymorphisms present in the TNF promoter region has shown to influence the gene transcription. Leprosy displays different clinical manifestations according to the immune responses of the individual infected with Mycobacterium leprae. In this study, we evaluated the single nucleotide polymorphisms (SNPs) -238 G/A (rs361525), -308 G/A (rs1800629), -857 C/T (rs1799724), -863 A/C (rs1800630) and -1031 T/C (rs1799964) in the promoter region of the TNF to see whether these SNPs influence host-susceptibility to leprosy and the different clinical manifestation. Nucleotide sequencing was performed with DNA samples from 108 leprosy patients and 253 control subjects. An association between -1031 C/C genotype and protection from leprosy was observed when leprosy patients were compared to controls (OR 0.11; 95% CI=0.01-0.82; p=0.012). The -857 C/T genotype may be associated with susceptibility to leprosy (OR=1.81; 95% CI=1.09-3.00; p=0.028). Similar genotype and allele frequencies for the SNPs -308 G/A and -238 G/A were observed between leprosy patients and control subjects. Altogether, TNF polymorphisms in the promoter region may be predictive of leprosy outcome.

Comparison of percentage body fat and body mass index for the prediction of inflammatory and atherogenic lipid risk profiles in elderly women

OBJECTIVE

To compare the clinical classification of the body mass index (BMI) and percentage body fat (PBF) for the prediction of inflammatory and atherogenic lipid profile risk in older women.

METHOD

Cross-sectional analytical study with 277 elderly women from a local community in the Federal District, Brazil. PBF and fat-free mass (FFM) were determined by dual energy X-ray absorptiometry. The investigated inflammatory parameters were interleukin 6 and C-reactive protein.

RESULTS

Twenty-five percent of the elderly women were classified as normal weight, 50% overweight, and 25% obese by the BMI. The obese group had higher levels of triglycerides and very low-density lipoproteins than did the normal weight group (P≤0.05) and lower levels of high-density lipoproteins (HDL) than did the overweight group (P≤0.05). According to the PBF, 49% of the elderly women were classified as eutrophic, 28% overweight, and 23% obese. In the binomial logistic regression analyses including age, FFM, and lipid profile, only FFM (odds ratio [OR]=0.809, 95% confidence interval [CI]: 0.739-0.886; P<0.0005) proved to be a predictor of reaching the eutrophic state by the BMI. When the cutoff points of PBF were used for the classification, FFM (OR=0.903, CI=0.884-0.965; P=0.003) and the total cholesterol/HDL ratio (OR=0.113, CI=0.023-0.546; P=0.007) proved to be predictors of reaching the eutrophic state.

CONCLUSION

Accurate identification of obesity, systemic inflammation, and atherogenic lipid profile is key to assessing the risk of cardiometabolic diseases. Classification based on dual energy X-ray absorptiometry measures, along with biochemical and inflammatory parameters, seems to have a great clinical importance, since it allows the lipid profile eutrophic distinction in elderly overweight women.

Lack of association between apolipoprotein E genotypes and cognitive performance in the non-demented elderly

AIM

The ε4 alelle of the apolipoprotein E gene is known to be a key genetic risk factor for Alzheimer's disease and possibly for other neurological disorders. Some evidence in the literature indicates that the ε4 allele interferes with human cognition independently of chronological age and diagnosis of Alzheimer's disease. The present study investigated the correlation of allelic variants of apolipoprotein E with the cognitive performance of elderly individuals without apparent cognitive impairment.

METHODS

This was a cross-sectional analysis that included 213 non-demented elderly individuals (age ≥60 years) from the Brazilian Federal District. The analysis assessed the subjects for cognitive domains including short- and long-term episodic memory, processing speed, and attention and executive functions. Sociodemographic and other clinical characteristics were gathered and analyzed as covariates.

RESULTS

Being sufficiently powered, the present study did not identify differential performance across apolipoprotein E genotypes. There was no influence of age, gender, marital status, schooling, depressive symptoms or use of central nervous system depressants when the analyses were controlled for such factors.

CONCLUSIONS

Our findings suggest that the ε4 allele does not contribute to detectable cognitive decline within the context of non-dementia.

The effect of aerobic exercise intensity on attenuation of postprandial lipemia is dependent on apolipoprotein E genotype

OBJECTIVE

To investigate the effect of aerobic exercise intensity on postprandial lipemia according to allelic variants of the apolipoprotein E gene.

METHODS

Three groups of 10 healthy men each were formed based genotyping of the APOE gene, rested or performed 500 Kcal tests in a random sequence separated by a minimum 48 h interval, as follows: (a) no exercise (control), (b) intense intermittent exercise, (c) moderate continuous exercise. Each test series was completed 30-min before ingestion of a high-fat meal (1 g fat/kg). Venous blood was collected before and at 1, 2, 3 and 4 h after the high-fat meal. Postprandial lipemia was assessed using the area under the curve approach as well as the kinetic profile of mean lipid variables. Statistical significance was adopted at P ≤ 0.05 level.

RESULTS

The main results show that, in the moderate continuous exercise, total postprandial cholesterolemia was higher in ɛ4 than in ɛ2 carriers, whereas under intense intermittent exercise, total and LDL cholesterolemia were higher in ɛ4 than in ɛ2 and ɛ3 carriers. There was no difference in the lipemic profile of the subjects across APOE genotypes at baseline.

CONCLUSION

Moderate and intense exercise were effective in attenuating PPL in both ɛ2 and ɛ3 subjects, with ɛ2 subjects being more susceptible to the lipid lowering effect of moderate training than ɛ3 subjects. Carriers of the ɛ4 allele, however, showed no attenuation of postprandial lipemia.

The influence of ACE genotype on cardiovascular fitness of moderately active young men

BACKGROUND

The angiotensin I-converting enzyme gene (ACE gene) has been broadly studied as for cardiorespiratory fitness phenotypes, but the association of the ACE genotype to middle-distance running has been poorly investigated.

OBJECTIVE

This study investigated the possible influence of Angiotensin-Converting Enzyme (ACE) genotype (I/D) on cardiovascular fitness and middle-distance running performance of Brazilian young males. The validity of VO(2max) to predict the ACE genotype was also analyzed.

METHODS

A homogeneous group of moderately active young males were evaluated in a 1,600 m running track test (V1600m; m.min(-1)) and in an incremental treadmill test for VO(2max) determination. Subsequently, the actual and the predicted [(0.177*V1600m) + 8.101] VO(2max) were compared to ACE genotypes.

RESULTS

The VO(2max) and V1600m recorded for DD, ID and II genotypes were 45.6 (1.8); 51.9 (0.8) and 54.4 (1.0) mL.kg(-1).min(-1) and 211.2 (8.3); 249.1 (4.3) and 258.6 (5.4) m.min(-1) respectively, and were significantly lower for DD carriers (p< 0.05). The actual and predicted VO(2max) did not differ from each other despite ACE genotype, but the agreement between actual and estimated VO(2max) methods was lower for the DD genotype.

CONCLUSION

It was concluded that there is a possible association between ACE genotype, cardiovascular fitness and middle-distance running performance of moderately active young males and that the accuracy of VO(2max) prediction may also depend on the ACE genotype of the participants.

Risk of glycemic disorder in elderly women adjusted by anthropometric parameters and cytokine genotypes

OBJECTIVE

The objective of the present study was to examine the association of glucose intolerance and type-2 diabetes mellitus with the -174 G > C and -308 G > A allelic variations of IL-6 and TNF-α, respectively, through anthropometric measurements and age strata.

METHODS

This is a cross-sectional study using data from 285 community dwelling elderly women who underwent physical, biochemical, and genetic examinations.

RESULT

Genotype-unadjusted analysis revealed that the risk of glucose intolerance and diabetes in elderly women with elevated BMI was 1.71 and 2.82 times higher, respectively, whereas age and conicity index did not show predictive value. Prevalence ratios for glucose intolerance and diabetes across allelic variants of IL-6 and TNF-α did not associate IL-6 with unbalanced glucose levels, despite adjustment for BMI, age, and conicity index. Conversely, carriers of the TNF-α A allele were 2.06 and 5.58 times more likely to exhibit glucose intolerance and diabetes, respectively, compared to GG homozygotes.

CONCLUSION

Our results suggest that bearing the A allele of the -308 G > A polymorphism of TNF-α predisposes to anthropometric measure-sensitive impaired glucose metabolism in older women.

Dietary fat and apolipoprotein genotypes modulate plasma lipoprotein levels in Brazilian elderly women

Studies show that genetic polymorphisms in apolipoproteins, which are in charge of lipid transport, predispose to atherogenic dyslipidemia. This study aimed to investigate the impact of apolipoprotein E, A5, and B genotypes and dietary intake on lipid profile in a sample of elderly women in Brazil. Two hundred and fifty-two women (60 years or older) living in the outskirts of the Brazilian Federal District underwent clinical and laboratory assessments to characterize glycemic and lipidemic variables, and also to exclude confounding factors (smoking, drinking, hormone replacement, cognitive impairment, physical activity). Three-day food records were used to determine usual dietary intake, whereas genotypic evaluations were in accordance to established methodologies. Genotype frequencies were consistent with the Hardy-Weinberg equilibrium. Prior to adjustment, individuals carrying the epsilon2 allele showed higher serum levels of triglycerides (P<0.05) and VLDL (P<0.005) compared to epsilon4 carriers, whereas LDL levels were considerably elevated in epsilon4 compared to epsilon2 carriers. In the presence of high intake of total fat or a low ratio of polyunsaturated to saturated fatty acid, epsilon4 carriers lost protection against hypertriglyceridemia. There was no association of the apolipoprotein A5 and B genotypes with lipidemic levels independently of the fat intake regimen. Results are suggestive of a dysbetalipoproteinemic-like phenotype in postmenopausal women, with remarkable gene-diet interaction.

[Use of tissue plasminogen activator factor for acute ischemic stroke]

PURPOSE

To evaluate thrombolytic therapy with rt-PA for acute stroke within 6h of symptom onset, and assessment of neurologic outcome.

METHODS

We studied 6 patients, four women, mean age 63 +/- 18 years, with severe neurologic deficit within 6h of stroke onset, and with no spontaneous improvement. The stroke was embolic in 3, and thrombotic in the others. All patients were submitted to a head CT scan followed by either a cerebral angiography in 3 patients, or a transcranial Doppler, in the other 3 for assessment of arterial obstruction, and patency after thrombolytic therapy. We used 0.9 mg/kg of rt-PA, IV, over 60 min in 5 patients, and 0.5 mg/kg by intra-arterial infusion, over 60 min, in one. At the beginning a bolus of 10% of the total dose was delivered during 1 to 2 min. Head scan was repeated 24h and 7 days after treatment to detect ischemic areas and hemorrhagic complications.

RESULTS

Middle cerebral artery occlusion was observed in 5 patients and posterior cerebral artery occlusion in one. The obstruction was cleared in 4 patients with persistence of the patency after 24h. A complete neurologic recovery was found in one patient, and a partial recovery in three. In two patients there was failure of arterial recanalization with no neurologic recovery. Only one patient had hemorrhagic transformation of ischemic tissue, without neurologic worsening. Death occurred in one patient due to pulmonary infection.

CONCLUSION

Arterial patency with thrombolytic therapy was effective in 4 of our 6 patients. All 4 patients also disclosed a certain degree of neurologic improvement, rt-PA can be successfully used in selected patients up to 3h of the event onset, as shown in randomized studies.

Hemobilia: transcatheter occlusive therapy and long-term follow-up

Eight patients with life-threatening hemobilia were treated by percutaneous transcatheter occlusive therapy. The bleeding was caused by a traumatic pseudoaneurysm of the hepatic artery in 6 cases (auto accident in 4, surgery in 1, biliary drainage in 1) and a true aneurysm of the hepatic artery in 2 (unknown etiology in 1 and mycotic in 1). Arterial catheterization was used in all cases except for one in which a direct percutaneous puncture was performed. Gelfoam alone was used as embolic material in 3 patients. In 1 patient each, the material used was gelfoam plus coils, coils alone, blood clot, n-butyl-cyanoacrylate and an occluding balloon catheter. In all cases the bleeding stopped and did not recur during the follow-up period which ranged from 9 months to 14 years. This experience indicates that transcatheter occlusive therapy is an effective method for the treatment of severe hemobilia.

Dissociated effects of somatostatin analogs on arginine-induced insulin, glucagon and growth hormone release in acromegalic patients

Two analogs of somatostatin (Ala2,D-Trp8,D-Cys14-Somatostatin and L-5F-Trp8-Somatostatin) infused into acromegalics at the rate of 4.5 micrograms/min suppressed arginine-stimulated growth hormone release more strongly than 6 micrograms/min somatostatin (110 +/- 11% and 129 +/- 14%, respectively). Under the same conditions the two somatostatin analogs induced a much smaller inhibition of insulin (33 +/- 13% and 44 +/- 18%) and glucagon (28 +/- 10% and 45 +/- 17%, respectively) release than somatostatin did. Somatostatin analogs with dissociated actions could be promising for the treatment of diseases such as acromegaly, diabetes mellitus and some ectopic hormone syndromes.