The orange light emitting luciferase from the rare Euryopa clarindae adult railroadworm (Coleoptera:Phengodidae): structural/functional and evolutionary relationship with green and red emitting luciferases.

Railroadworms luciferases emit the widest range of bioluminescence colors among beetles, ranging from green to red, being model enzymes to investigate the structure and bioluminescence colors relationships. Only three active railroadworms luciferases from the larval stage have been cloned and investigated: the Phrixothrix hirtus head lanterns red-emitting luciferase (PhRE); the Phrixothrix vivianii lateral lanterns green emitting luciferases (PvGR) and the Phengodes sp. dorsal lanterns yellow-green emitting luciferase (Ph). No active luciferase emitting in the yellow-orange region, however, has been cloned yet. Here we report the cloning and characterization of the orange emitting luciferase from the adult males of a rare Brazilian Cerrado railroadworm, Euryopa clarindae, and the transcriptional identification of two isozymes from the Amazon forest Mastinomorphus sp. railroadworm. The luciferase of E. clarindae has 548 residues, emits orange bioluminescence (600 nm), and displays intermediate kinetic values [KM(luciferin) = 50 µM, KM(ATP) ~ 170 µM] between those reported for green-emitting lateral lanterns and red emitting head lanterns luciferases. It displays 74-78% identity with the lateral lanterns luciferases of other railroadworms and 70% with the head lantern PhRE luciferase, and 96% with the larval Mastinomorphus sp. Mast-1, suggesting that this larva could be from the Euryopa genus. The phylogenetic analysis and kinetic/functional properties, place this orange-emitting enzyme as an intermediate form between the green-emitting lateral lanterns and red-emitting head lanterns luciferases. Major structural differences that could be associated with bioluminescence color determination are a relatively larger cavity size, and substitutions in the loops 223-235 and 311-316, especially N/C/T311, and their interactions which may help to close the bottom of LBS.

Genetic divergence through joint analysis of morphoagronomic and molecular characters in accessions of Jatropha curcas.

The aim of this study was to investigate the genetic divergence between accessions of Jatropha curcas through joint analysis of morphoagronomic and molecular characters. To this end, we investigated 11 morphoagronomic characters and performed molecular genotyping, using 23 inter-simple sequence repeat (ISSR) primers in 46 accessions of J. curcas. We calculated the contribution of each character on divergence using analysis of variance. The grouping among accessions was performed using the Ward-MLM (modified location model) method, using morphoagronomic and molecular data, whereas the cophenetic correlation was obtained based on Gower's algorithm. There were significant differences in all growth-related characteristics: number of primary and secondary branches per plant, plant height, and stem diameter. For characters related to grain production, differences were found for number of fruit clusters per plant and number of inflorescence clusters per plant and average number of seeds per fruit. The greatest phenotypic variation was found in plant height (59.67- 222.33 cm), whereas the smallest variation was found in average number of seeds per fruit (0-2.90), followed by the number of fruit clusters per plant (0-8.67). In total, 94 polymorphic ISSR fragments were obtained. The genotypic grouping identified six groups, indicating that there is genetic divergence among the accessions. The most promising crossings for future hybridization were identified among accessions UFRB60 and UFVJC45, and UFRB61 and UFVJC18. In conclusion, the joint analysis of morphoagronomic characters and ISSR markers is an efficient method to assess the genetic divergence in J. curcas.

Vascular endothelial growth factor as an angiogenesis biomarker for the progression of autosomal dominant polycystic kidney disease.

Autosomal dominant polycystic kidney disease (ADPKD) is a hereditary nephropathy characterized by abnormal growth of epithelial cells. Genetic factors, including the vascular endothelial growth factor (VEGF) gene, play an important role in its progression. The main aim of this study was to evaluate the influence of VEGF-C936T polymorphism in the development and progression of ADPKD. In total, 302 individuals were studied and divided into two groups: G1 (73 patients with ADPKD) and G2 (229 individuals without the disease). Among the patients, 46 (63%) progressed to end-stage renal disease (ESRD), and required hemodialysis and/or renal transplant. These patients were re-grouped into G1-A for progression analysis. A peripheral blood sample was obtained from all subjects; the DNA was extracted and the VEGF-C936T polymorphism analyzed using polymerase chain reaction/restriction fragment length polymorphism. The significance level was set at P < 0.05. The homozygous wild-type genotype (C/C) was predominant in G1 (78%) and G2 (79%; P = 0.9249). We observed a significant reduction in the mean age of patients with the risk allele (C/T + T/T = 44.3 ± 13.4 years) compared to the C/C genotype (52.2 ± 9.6 years; P = 0.047) in G1-A. In conclusion, the VEGF-C936T polymorphism does not discriminate patients from controls. However, the presence of the T allele appears to accelerate the progression of ADPKD, anticipating ESRD, thereby suggesting its importance in the prognosis of the disease. However, the importance role played by VEGF gene variants in different populations and larger sample sizes must be verified.

Amlodipine reduces blood pressure during dynamic resistance exercise in hypertensive patients.

This study investigated the effect of the dihydropyridine calcium channel antagonist, amlodipine, on blood pressure (BP) during resistance exercise performed at different intensities in hypertensives. Eleven hypertensives underwent 4 weeks of placebo and amlodipine (random double-blinded crossover design). In each phase, they performed knee extension exercise until exhaustion following three protocols: one set at 100% of 1 RM (repetition maximum), three sets at 80% of 1 RM, and three sets at 40% of 1 RM. Intraarterial BP was measured before and during exercise. Amlodipine reduced maximal systolic/diastolic BP values achieved at all intensities (100% = 225 ± 6/141 ± 3 vs. 207 ± 6/130 ± 6 mmHg; 80% = 289 ± 8/178 ± 5 vs. 273 ± 10/169 ± 6 mmHg; 40% = 289 ± 10/176 ± 8 vs. 271 ± 11/154 ± 6 mmHg). Amlodipine blunted the increase in diastolic BP that occurred during the second and third sets of exercise at 40% of 1RM (+75 ± 6 vs. +61 ± 5 mmHg and +78 ± 7 vs. +64 ± 5 mmHg, respectively). Amlodipine was effective in reducing the absolute values of systolic and diastolic BP during resistance exercise and in preventing the progressive increase in diastolic BP that occurs over sets of low-intensity exercise. These results suggest that systemic vascular resistance is involved in BP increase during resistance exercise, and imply that hypertensives receiving amlodipine are at lower risk of increased BP during resistance exercise than non-medicated patients.

Proximal tibia fracture in a patient with incomplete spinal cord injury associated with robotic treadmill training.

STUDY DESIGN: One case report of proximal tibia fracture in a patient with incomplete spinal cord injury (SCI) associated with robotic treadmill training. OBJECTIVE: To raise the awareness that bone densitometry may be recommended before starting the robotic treadmill therapy, as well as the active vigilance of symptoms after therapy. SETTING: Institute of Physical and Rehabilitation Medicine, Lucy Montoro Institute for Rehabilitation, Hospital das Clínicas, School of Medicine, University of São Paulo, São Paulo, Brazil. CASE REPORT: The patient, female gender, with a fracture of vertebra T12 and arthrodesis from T9 to L1 (American Spinal Injury Association Classification (ASIA-C)). Training on Lokomat consisted of five 30-min weekly sessions, under the supervision of a qualified professional. At the beginning of the 19th session, the patient complained of pain in the anterior region of the left knee. Lokomat and any other body support therapy were discontinued. Magnetic resonance imaging (MRI) evidenced a transverse, oblique, metaphyseal proximal anterior and medial tibial fracture. CONCLUSION: Fractures are among the chronic complications of a SCI, affecting 34% and many times arising from minimal traumas. Lokomat resembles physiological walking, and more studies show its benefits. Many studies encourage the use of robotic devices for the rehabilitation of lower limbs, but there are still several unanswered questions. However, there are not enough studies to show whether there is a higher risk of fracture incidence in patients with osteopenia or osteoporosis who trained on the Lokomat.

Influence of vascular endothelial growth factor and alpha-fetoprotein on hepatocellular carcinoma.

We evaluated the influence of the vascular endothelial growth factor (VEGF) -C936T polymorphism on prognosis of hepatocellular carcinoma (HCC), cirrhosis, and hepatitis C virus (HCV) infection. Serum VEGF and alpha-fetoprotein (AFP) levels were determined and used to characterize sensitivity and specificity. A total of 285 subjects were studied: 68 HCC, 118 cirrhosis, 43 HCV, and 56 healthy controls. Prevalence of the VEGF -C936T polymorphism and serum levels of VEGF and AFP were analyzed by polymerase chain reaction-restriction fragment length polymorphism and enzyme-linked immunosorbent assay, respectively. The genotype CC (frequencies between 63.24 and 76.79%; P > 0.05) and the C allele (absolute frequencies from 0.816 to 0.884, P > 0.05) were prevalent in all groups. Higher VEGF levels in HCC patients (588.0 ± 501.0 pg/mL) were observed, particularly in patients with the T allele in VEGF -C936T (764.4 ± 571.7 pg/mL) compared to those in the other groups (P < 0.05). The same trend occurred with AFP levels (HCC = 8.522 ± 23.830; cirrhosis = 12.7 ± 59.3; HCV = 4.6 ± 4.7; control = 2.7 ± 1.8 ng/mL; P = 0.005). Levels of VEGF and AFP showed sensitivity of 65 and 28% and specificity of 85 and 99%, respectively, for HCC patients. In conclusion, the VEGF -C936T polymorphism is not associated with HCC but the mutant allele (T) increases VEGF levels in HCC patients. VEGF could be a potential biomarker for HCC, while AFP could be used to distinguish between patients with HCC and cirrhosis or HCV.

Effects of physical exercise on the P38MAPK/REDD1/14-3-3 pathways in the myocardium of diet-induced obesity rats.

Obesity is associated with myocardial insulin resistance and impairment of the mammalian target of rapamycin (mTOR) signaling pathway. The activation of the mTOR cascade by exercise has been largely shown in skeletal muscle, but insufficiently analyzed in myocardial tissue. In addition, little is known regarding the mTOR upstream molecules in the hearts of obese animals and even less about the role of exercise in this process. Thus, the present study was aimed to evaluate the effects of physical exercise on P38 Mitogen-Activated Protein Kinase (P38MAPK) phosphorylation and the REDD1 (regulated in development and DNA damage responses 1) and 14-3-3 protein levels in the myocardium of diet-induced obesity (DIO) rats. After achievement of DIO and insulin resistance, Wistar rats were divided in 2 groups: sedentary obese rats and obese rats performed treadmill running (50-min/day, 5 days per week velocity of 1.0 km/h for 2 months). Forty-eight hours after the final physical exercise, the rats were killed, and the myocardial tissue was removed for Western blot analysis. DIO increased the REDD1 protein levels and reduced the 14-3-3 protein levels and P38MAPK, mTOR, P70S6k (p70 ribosomal S6 protein kinase), and 4EBP1 (4E-binding protein-1) phosphorylation. Interestingly, physical exercise reduced the REDD1 protein levels and increased the 14-3-3 protein levels and P38MAPK, mTOR, P70S6k, and 4EBP1 phosphorylation. Moreover, exercise increased the REDD1/14-3-3 association in the heart. Our results indicate that the phospho-P38MAPK, REDD1, and 14-3-3 protein levels were reduced in the myocardium of obese rats and that physical exercise increased the protein levels of these molecules.

Genetic diversity and selection gain in the physic nut (Jatropha curcas).

The use of efficient breeding methods depends on knowledge of genetic control of traits to be improved. We estimated genetic parameters, selection gain, and genetic diversity in physic nut half-sib families, in order to provide information for breeding programs of this important biofuel species. The progeny test included 20 half-sib families in 4 blocks and 10 plants per plot. The mean progeny heritability values were: 50% for number of bunches, 47% for number of fruits, 35% for number of seeds, 6% for stem diameter, 26% for number of primary branches, 14% for number of secondary branches, 66% for plant height, and 25% for survival of the plants, demonstrating good potential for early selection in plant height, number of branches, and number of fruits per plant. In the analysis of genetic diversity, genotypes were divided into 4 groups. Genotypes 18, 19, 20, and 8 clustered together and presented the highest means for the vegetative and production. Lower means were observed in the 17, 12, 13, and 9 genotypes from the same group. We detected genetic variability in this population, with high heritability estimates and accuracy, demonstrating the possibility of obtaining genetic gains for vegetative characters and production at 24 months after planting.

Reversion of steatosis by SREBP-1c antisense oligonucleotide did not improve hepatic insulin action in diet-induced obesity mice.

The literature has associated hepatic insulin action with NAFLD. In this sense, treatments to revert steatosis and improve hepatic insulin action become important. Our group has demonstrated that inhibition of Sterol Regulatory Element Binding Proteins-1c (SREBP-1c) reverses hepatic steatosis. However, insulin signals after NAFLD reversion require better investigation. Thus, in this study, we investigated if the reversal of NAFLD by SREBP-1c inhibitor results in improvement in the hepatic insulin signal in obesity mice. After installation/achievement of diet-induced obesity and insulin resistance, Swiss mice were divided into 3 groups: i) Lean, ii) D-IHS, diet-induced hepatic steatosis [no treatment with antisense oligonucleotide (ASO)], and iii) RD-IHS, reversion of diet-induced hepatic steatosis (treated with ASO). The mice were treated with ASO SREBP-1c as previously described by our group. After ASO treatment, one set of animals was anesthetized and used for in vivo test, and another mice set was anesthetized and used for histology and Western blot analysis. Reversion of diet-induced hepatic steatosis did not change blood glucose, glucose decay constant (k(ITT)), body weight, or serum insulin levels. In addition, results showed that the protocol did not improve insulin pathway signaling, as confirmed by the absence of changes in IR, IRS1, Akt and Foxo1 phosphorylation in hepatic tissue. In parallel, no alterations were observed in proinflammatory molecules. Thus, our results suggest that the inhibition of SREBP-1c reverts steatosis, but without improving insulin hepatic resistance.

Finger blood pressure during leg resistance exercise.

Blood pressure (BP) assessment during resistance exercise can be useful to avoid high BP, reducing cardiovascular risk, especially in hypertensive individuals. However, non-invasive accurate technique for this purpose is not available. The aim of this study was to compare finger photoplethysmographic (FPP) and intra-arterial BP values and responses during resistance exercise. Eight non-medicated hypertensive subjects (5 males, 30-60 years) were evaluated during pre-exercise resting period and during three sets of the knee extension exercise performed at 80% of 1RM until fatigue. BP was measured simultaneously by FPP and intra-arterial methods. Data are mean+/-SD. Systolic BP was significantly higher with FPP than with intra-arterial: at pre-exercise (157+/-13 vs. 152+/-10 mmHg; p<0.01) and the mean (202+/-29 vs. 198+/-26 mmHg; p<0.01), and the maximal (240+/-26 vs. 234+/-16 mmHg; p<0.05) values achieved during exercise. The increase in systolic BP during resistance exercise was similar between FPP and intra-arterial (+73+/-29 vs. +71+/-18 mmHg; p=0.59). Diastolic BP values and increases were lower with FPP. In conclusion, FPP provides similar values of BP increment during resistance exercise than intra-arterial method. However, it overestimates by 2.6+/-6.1% the maximal systolic BP achieved during this mode of exercise and underestimates by 8.8+/-5.8% the maximal diastolic BP.

Lipid peroxidation and antioxidant capacity of G6PD-deficient patients with A-(202G>A) mutation.

Glucose-6-phosphate dehydrogenase (G6PD) deficiency is an enzymopathy in which reduced NADPH concentrations are not maintained, resulting in oxidative damage. We evaluated G6PD activity, oxidative stress levels and Trolox equivalent antioxidant capacity in individuals with the A-(202G>A) mutation for G6PD deficiency. Five hundred and forty-four peripheral blood samples were screened for G6PD deficiency; we also analyzed lipid peroxidation products measured as thiobarbituric acid reactive species and Trolox equivalent antioxidant capacity. Men with the A-(202G>A) mutation had lower G6PD activity than women with the same mutation. Individuals with the A-(202G>A) mutation also differed in mean Trolox equivalent antioxidant capacity values but not for thiobarbituric acid reactive species values. We concluded that A-(202G>A) mutation is associated with reduced G6PD activity and increased Trolox equivalent antioxidant capacity.

Edible mushroom Agaricus sylvaticus can prevent the onset of atheroma plaques in hipercholesterolemic rabbits.

Since the involvement of free radicals in the pathophysiology of atherosclerosis was proposed, antioxidant supplementation arose as a potential strategy for the management of this disease. Thus, we decided to investigate the potential benefit of a natural antioxidant--rich edible mushroom (Agaricus sylvaticus) on the prevention of atherosclerosis. New Zealand rabbits underwent atherosclerosis induction by feeding a cholesterol--enriched chow (Group A), while Group B simultaneously received edible mushroom A. sylvaticus water solution. Control group received standard rabbit chow only (Group C). At the end of 10 week treatment period serum samples were drawn for lipid profile, uric acid, thiobarbituric acid reactive substances (TBARS), and total antioxidant status (TAS). The area of aorta arteries taken by atheroma plaques was evaluated. Groups A and B presented higher cholesterol levels (p< 0.01) and reduced TAS (p<0.01), when compared to the Group C. However, TBARS and uric acid levels for Group B animals' were reduced, in comparison to Group A (p<0.05), and equals to group C. Moreover, animals from group A developed extensive atherosclerotic areas (47.0+/-14.0%), and that was prevented by the supplementation of A. sylvaticus (6.6+/-2.9%, p<0.01). Data suggested that A. sylvaticus can prevent the development of atherosclerosis in spite of hipercholesterolemia.

Relevance of apolipoprotein E4 for the lipid profile of Brazilian patients with coronary artery disease.

Apolipoprotein E (apoE - e2, e3, e4 alleles) plays a role in the regulation of lipid metabolism, with the e4 considered to be a risk factor for coronary artery disease (CAD). We aimed to evaluate the apoE polymorphisms in Brazilians with CAD and their influence on the lipid profile and other risk factors (hypertension, diabetes mellitus, smoking). Two hundred individuals were examined: 100 patients with atherosclerosis confirmed by coronary angiography and 100 controls. Blood samples were drawn to determine apoE polymorphisms and lipid profile. As expected, the e3 allele was prevalent in the CAD (0.87) and non-CAD groups (0.81; P = 0.099), followed by the e4 allele (0.09 and 0.14, respectively; P = 0.158). The e3/3 (76 and 78%) and e3/4 (16 and 23%) were the most common genotypes for patients and controls, respectively. The lipid profile was altered in patients compared to controls (P < 0.05), independently of the e4 allele. However, in the controls this allele was prevalent in individuals with elevated LDL-cholesterol levels only (odds ratio = 2.531; 95% CI = 1.028-6.232). The frequency of risk factors was higher in the CAD group (P < 0.05), but their association with the lipid profile was not demonstrable in e4 carriers. In conclusion, the e4 allele is not associated with CAD or lipid profile in patients with atherosclerosis. However, its frequency in the non-CAD group is associated with increased levels of LDL-cholesterol, suggesting an independent effect of the e4 allele on lipid profile when the low frequency of other risk factors in this group is taken into account.

Responses of skeletal muscle hypertrophy in Wistar rats to different resistance exercise models.

This study aimed to compare the effects of three different resistance exercise models on the quadriceps muscle cross-sectional area, as well as on mTOR phosphorylation and other pivotal molecules involved in the upstream regulation of mTOR. Twenty-four male Wistar rats were divided into untrained (control), endurance resistance training, strength resistance training, and hypertrophy resistance training (HRT) groups (n=6). After 12 weeks of training, the red portion of the quadriceps was removed for histological and Western blot analyses. The results showed that the quadriceps weight and cross-sectional areas in the exercised groups were higher than those of the untrained rats. However, the HRT group presented better results than the other two experimental groups. This same pattern was observed for mTOR phosphorylation and for the most pivotal molecules involved in the upstream control of mTOR (increase of PKB, 14-3-3, ERK, p38 MAPK, and 4E-BP1 phosphorylation, and reduction of tuberin, sestrin 2, REDD1, and phospho AMPK). In summary, our study showed that HRT leads to high levels of mTOR phosphorylation as well as of other proteins involved in the upstream regulation of mTOR.

Tissue transglutaminase crosslinks ataxin-1: possible role in SCA1 pathogenesis.

Transglutaminase type 2 (TG2) has recently been implicated in crosslinking of mutant huntingtin protein into aggregates. Here we show that TG2 also crosslinks spinocerebellar ataxia-1 (SCA1) gene product ataxin-1. HeLa cell lysates expressing GFP tagged ataxin-1 with 2, 30 or 82 glutamines showed covalent crosslinking of ataxin-1 when incubated with exogenously added TG2. This crosslinking was inhibited by TG2 inhibitor cystamine. SCA1 transgenic mice which overexpress the mutant ataxin-1 in cerebellar Purkinje cells showed elevated nuclear TG2 in the absence of ataxin-1 nuclear aggregates. The addition of purified TG2 to the nuclear extracts or addition of SCA1 nuclear TG2 to GFP-Q82 HeLa cell lysates resulted in the formation of insoluble aggregates. These data indicate that ataxin-1 is a substrate of TG2. Further, in SCA1 TG2 may translocate to the nucleus in response to nuclear accumulation of mutant ataxin-1 at early stages of the disease.

Intranasal administration of IGF-I improves behavior and Purkinje cell pathology in SCA1 mice.

Spinocerebellar ataxia type 1 (SCA1) is a neurodegenerative disease caused by the expansion of polyglutamine repeat within ataxin-1 protein. Cerebellar Purkinje cells are the primary targets of SCA1 pathology. These cells synthesize insulin-like growth factor-I (IGF-I) and express its receptors during their entire life. The aim of present study was to determine if intranasally administered IGF-I to SCA1 transgenic mice suppresses toxic effects of ataxin-1. Two-week old SCA1 heterozygous animals were randomly divided into two treatment groups of IGF-I (30 and 60 microg IGF-I/animal) and a vehicle-treated control group. The wildtype animals served as normal controls. IGF-I or vehicle was administered at 48 h intervals for the total of 10 doses. Animals were then subjected to rotarod test, sacrificed, brains removed and processed for immunohistochemical and Western blot analysis. Radiolabeled IGF-I and bioactive TAT peptide accumulated in the brains of SCA1 mice following intranasal administration validating the use of intranasal route. SCA1 mice showed SCA1 pathology with impaired motor function and downregulation of calcium binding proteins as compared to wildtype mice. However, 30 and 60 microg IGF-I-treated animals showed improved performance on the rotarod as compared to vehicle-treated SCA1 mice with significant improvement (p < 0.05) on day 3 in 60 microg IGF-I group. The immunohistochemical data further showed partial recovery in the expression of calbindin D28k and protein kinase C-gamma in Purkinje cells in IGF-I-treated SCA1 animals. Our results indicate that suppression of ataxin-1-mediated adverse effects by intranasal IGF-I treatment may be of a therapeutic value to treat SCA1.

Dynamic cardiomyoplasty in chronic Chagas' heart disease: clinicopathological data.

We report a 44-year-old man with chronic chagasic cardiomyopathy who underwent latissimus dorsi dynamic cardiomyoplasty and died 4 months later. The clinicopathological findings are discussed, and the literature is reviewed.

Mapping of bovine pericardium: physical and histopathologic tests.

BACKGROUND AND AIMS OF THE STUDY: This study was performed to identify the physical and histopathologic characteristics of different sections of glutaraldehyde-tanned bovine pericardium. METHODS: Ten pericardial sacs were obtained from animals aged from 18 to 36 months. Physical tests included shrinkage and mechanical resistance (rupture, elongation, tenacity index). Collagen and elastic fibers were evaluated in Gomori's trichrome-stained sections, hematoxylin and eosin, by PAS and Verhoeff's method. Studied areas were proximal to the great arteries, and the right atrial, right ventricular, left ventricular and left atrial regions. RESULTS AND CONCLUSIONS: Results showed that bovine pericardium does not have enough regional differences to identify any single region for bioprosthesis manufacture. However, histopathology showed better preservation of collagen and elastic fibers in the right ventricular region, implying that this area is more adequate as bioprosthetic material.

Comparison of vastus medialis obliquus: vastus lateralis muscle integrated electromyographic ratios between healthy subjects and patients with patellofemoral pain.

The purpose of this study was to compare vastus medialis obliquus:vastus lateralis muscle (VMO:VL) integrated electromyographic (IEMG) ratios of healthy subjects and patients with unilateral patellofemoral pain (PFP) under isotonic and isometric quadriceps femoris muscle contraction conditions. Subjects ranging in age from 18 to 35 years (mean = 28.06, SD = 5.97) were assigned to one of three groups on the basis of type of knee condition. In group 1, which consisted of seven healthy control subjects with no history of knee pathology, both knees were tested. In group 2, which consisted of nine patients with unilateral PFP, only the painful knee was tested. In group 3, which consisted of the same nine patients who comprised group 2, only the nonpainful knee was tested. Nonnormalized and normalized VMO:VL IEMG ratios were computed for ascending stairs, descending stairs, submaximal isometric contraction, and maximal isometric contraction (nonnormalized only). A two-way analysis of variance for repeated measures indicated VMO:VL ratios for isotonic stair-climbing activities were significantly greater than VMO:VL ratios for isometric contractions. Nonnormalized VMO:VL ratios in group 1 were significantly greater than nonnormalized VMO:VL ratios in the other two groups. Patients with PFP may have abnormal VMO:VL activation patterns, and isotonic quadriceps femoris muscle exercise may elicit more favorable muscle activation patterns than isometric exercise for patients with PFP.

Chronic experimental myocardial infarction produces antinatriuresis by a renal nerve-dependent mechanism.

The present study focused on the role of sympathetic renal nerve activity, in mediating congestive heart failure-induced sodium retention following experimental chronic myocardial infarction. Groups of male Wistar rats (240-260 g) were studied: sham-operated coronary ligation (CON3W, N = 11), coronary ligation and sham-operated renal denervation (INF3W, N = 19), 3 weeks of coronary ligation and sympathetic renal nerve denervation (INF3WDX, N = 6), sham-operated coronary ligation (N = 7), and 16 weeks of coronary ligation (INF16W, N = 7). An acute experimental protocol was used in which the volume overload (VO; 5% of body weight) was applied for 30 min after the equilibration period of continuous iv infusion of saline. Compared to control levels, VO produced an increase (P < 0.01, ANOVA) in urine flow rate (UFR; 570%) and urinary sodium excretion (USE; 1117%) in CON3W. VO induced a smaller increase (P < 0.01) in USE (684%) in INF3W. A similar response was also observed in INF16W. In INF3WDX, VO produced an immediate and large increase (P < 0.01) in UFR (547%) and USE (1211%). Similarly, in INF3W VO increased (P < 0.01) UFR (394%) and USE (894%). Compared with INF3W, VO induced a higher (P < 0.01) USE in INF3WDX, whose values were similar to those for CON3W. These results suggest that renal sympathetic activity may be involved in sodium retention induced by congestive heart failure. This premise is supported by the observation that in bilaterally renal denervated INF3WDX rats myocardial infarction was unable to reduce volume expansion-induced natriuresis. However, the mechanism involved in urinary volume regulation seems to be insensitive to the factors that alter natriuresis.