Output relations of humeral circumflex arteries and its variations / Relaciones de las arterias circunflejas humerales y sus variaciones

A large range of variability marks the branching pattern of the axillary artery. The knowledge of the anatomical variations and this pattern is essential to diagnostic and therapeutic approaches, including surgery, of the axillary region. The aim of this study was to observe the different possible origins of circumflex humeral arteries and to measure the length and diameter of each vessel. In our study, 24 armpits from adult cadavers (fixed in tamponed formalin 10%) were dissected. The data were analyzed with a digital caliper and the results expressed as Mean ± SD. In majority of specimens, posterior circumflex humeral artery (PCHA) arose from subscapular artery (SSA) (54.16%) and had an average diameter of 3.92±0.41 mm. The anterior circumflex humeral artery was a branch from axillary artery (AA) in the majority of the specimens (62.5%) with an average diameter of 1.83±0.68 mm. Circumflex humeral arteries can arise from SSA, deep brachial artery and AA. The result of this study is an interesting data for origin, length and diameter of these vessels, contributing to the knowledge of these variations occurrence.

Una amplia gama de variabilidad marca el patrón de ramificación de la arteria axilar. El conocimiento de las variaciones anatómicas de este patrón es esencial para enfoques de diagnóstico y terapéuticos, incluyendo la cirugía de la región axilar. El objetivo fue observar los diferentes orígenes posibles de arterias circunflejas humerales y medir la longitud y el diámetro de cada vaso. En el estudio se disecaron 24 axilas de cadáveres adultos (fijados en formalina tamponada al 10%). Los datos se analizaron con un calibrador digital y los resultados se expresaron como Media ± DS. En la mayoría de los especímenes, la arteria circunfleja humeral posterior surgió de la arteria subescapular (ASE) (54,16%) con un diámetro medio de 0,41±3,92 mm. En la mayoría de los especímenes (62,5%), la arteria circunfleja humeral anterior era una rama de la arteria axilar (AA) con un diámetro medio de 0,68±1,83 mm. Las arterias circunflejas humerales pueden surgir de la ASE, de la arteria braquial profunda y AA. El resultado de este estudio es un dato interesante para el origen, la longitud y el diámetro de los vasos, lo que contribuye al conocimiento de la ocurrencia de estas variaciones.

Does prefrontal cortex transcranial direct current stimulation influence the oxygen uptake at rest and post-exercise?

The study evaluated the effect of transcranial direct current stimulation (tDCS) applied over prefrontal cortex on the oxygen uptake (V˙ O2) at rest and during post-exercise recovery. The V˙ O2 was assessed in eleven healthy subjects before, during tDCS (sham or anodal tDCS, 2 mA, 20 min), and 30-min following isocaloric aerobic exercise (~200 kcal). During tDCS, no changes were observed on V˙ O2 compared to baseline (P=0.95) and sham condition (P=0.85). The association between isocaloric exercise and anodal tDCS increased the V˙ O2 throughout 30-min recovery compared to sham condition (P<0.001). Therefore, the energy expenditure within the excess post-exercise oxygen consumption (EPOC) period, after anodal tDCS was approximately 19% higher compared to the sham condition (P<0.05). In conclusion, anodal tDCS applied on the prefrontal cortex combined with submaximal aerobic exercise increased the EPOC, enhancing the V˙ O2 and energy expenditure at least for 30-min of recovery.

The relationship between rating of perceived exertion and muscle activity during exhaustive constant-load cycling.

The aims of this study were to verify the relationship between rating of perceived exertion (RPE) and electromyography (EMG) increases during exhaustive constant-load cycling bouts and, to compare and to correlate the power outputs corresponding to perceived exertion threshold (PET) and neuromuscular fatigue threshold (NFT). 11 men completed 3-4 different exhaustive constant-load cycling bouts on a cycle ergometer, being RPE and EMG measured throughout the bouts. The linear regression of the RPEslope and EMGslope against the power output identified the PET and NFT intensity, respectively. There was a significant relationship between RPEslope and EMGslope (R(2)=0.69; P<0.01). However, the linearity of RPEslope (R(2)=0.93±0.07) was significantly higher (P<0.001) than EMGslope (R(2)=0.63±0.25). In addition, the RPEslope and EMGslope were related to time to exhaustion (r=-0.59 and r=-0.60; P<0.001). There was no significant difference (P=0.42) between PET (201.5±27.9W) and NFT (210.3±22.6W) and they were significantly correlated (r=0.78; P=0.005). Therefore, the RPE and EMG increases during exhaustive constant-load cycling bouts are related and, PET and NFT intensities are similar and closely associated.

Comparison of electromyography fatigue threshold in lower limb muscles in trained cyclists and untrained non-cyclists.

The purpose of this study was to identify and compare the Electromyographic Fatigue Threshold (EMG(FT)) determined in the Vastus Lateralis (VL), Rectus Femoris (RF), Biceps Femoris (BF), Semitendinosus (ST) and Tibialis Anterior (TA) during stationary cycling in trained cyclists and non-cyclists. Using a cycle ergometer, 13 cyclists (28.4 +/- 6.9 years; 70.3 +/- 13 kg; 176.1 +/- 8.5 cm) and 11 non-cyclists (25.8 +/- 4 years; 73 +/- 9.1 kg; 175 +/- 6.4 cm), performed a maximum incremental test (ITmax) (90 rpm) to determine the (EMG(FT)). Maximal power output (W(PEAK)) reached by cyclists was higher than for non-cyclists (372.6 W and 248.9 W respectively) (P < 0.01). For the five muscles analyzed in cyclists, EMG(FT) occurred at 85.7% of cases in the VL, 92.9% in RE 78.6% in BE 78.6% in ST and 50% in TA, while in the non-cyclists group, this occurrence was 100% to muscle VL, 100% to RF, 92.6% to BF, 78.6% to ST, and 78.6% to TA. Analyzing the percentage corresponding to the power at EMG(FT) in relation to W(PEAK) reached, no differences between groups were observed for RF, BF and ST, however VL and TA, as well as the mean from all muscles were lower for cyclists than non-cyclists (P < 0.05). The present results showed that EMG(FT) is more easily identified in RF and VL muscles for both groups, and it may be an interesting method to evaluate the adaptive responses from aerobic and anaerobic metabolisms during cycling training programs.

Association between the electromyographic fatigue threshold and ventilatory threshold.

The objective of this study is to verify the coincidence between the occurrence of the electromyographic fatigue threshold (EMGth) and the ventilatory threshold (Vth) in an incremental test in the cyclosimulator, as well as to compare the calculation of the RMS from the EMG signal using different time windows. Thirteen male cyclists (73.7 +/- 12.4 kg and 174.3 +/- 6.2 cm) performed a ramp incremental test (TI) in a cyclosimulator until voluntary exhaustion. Before the start of each TI subjects had the active bipolar electrodes placed over the superficial muscles of the quadriceps femoris (QF) of the right leg: rectus femoris (RF), vastus medialis (VM) and vastus lateralis (VL). The paired student's t test, pearson's correlation coefficient and the analysis method described by Bland and Altman for the determination of the concordance level were used for statistical analysis. The significance level adopted was P < 0.05. Although no significant differences were found between Vth and the EMGth calculated from windows of 2, 5, 10, 30 and 60 seconds in the studied muscles, it is suggested that the EMGth values determined from the calculation of the RMS curve with windows of 5 and 10 seconds seem to be more appropriate for the calculation of the RMS curve and determination of EMGth from visual inspection.

The efficiency of pedaling and the muscular recruitment are improved with increase of the cadence in cyclists and non-cyclists.

The objective of this study was to compare the efficiency of pedaling (EP) and the electromyographic activity (EMG) between cyclists and non-cyclists during cycling in different cadences. Using a cyclosimulator, 12 cyclists (26.5 +/- 4.5 years; 68.2 +/- 10.5 kg; 175.6 +/- 8.2 cm) and 9 non-cyclists (25.1 +/- 4.3 years; 72.6 +/- 9.8 kg; 174.6 +/- 6.2 cm), performed a maximum incremental test (ITmax), and subsequently, two constant load tests (Tconst) in different cadences (60 and 90 rpm) at the intensity of the electromyographic fatigue threshold (EMGth) determined in ITmax. Before the Tconst, the subjects performed a maximum isometric voluntary contraction (MIVC) for the normalization of the EMG data of Tconst. During Tconst, the EMG of the studied muscles was recorded, as well as the EP Although there was a trend of higher values in all occasions for the cyclists, there were no statistical differences in EP and the EMG when compared in a same cadence between groups. However, when the EMG is compared in different cadences in the same group, there was a significant increase (p < 0.05) in the muscles that work during the recovery phase with the increase in cadence, in both groups, being more evident in the cyclists. In conclusion, the hypothesis that cyclists had better technique than non-cyclists was not confirmed statistically. However, it was found that the increase in cadence improves the EP and the recruitment in both groups.

Biocompatibilidade e comportamento de compósitos de hidroxiapatita em falha óssea na ulna de coelhos / Biocompatibility and behavior of hydroxyapatite on bone defect on rabbit's ulna

Avaliaram-se os compósitos de hidroxiapatita sintética e carbono (HAC) e hidroxiapatita sintética, carbono e fosfato biácido de sódio (HACF), ambos na forma sólida, como substituto ósseo em 36 coelhos adultos. Após protocolos anestésico e cirúrgico habituais, retirou-se um fragmento de aproximadamente 2cm de comprimento no terço médio da ulna esquerda. Os animais do grupo 1 receberam, em cada falha provocada, blocos de HAC e HACF, e os do grupo 2 somente HAC. Os do grupo 3 não receberam tratamento. Os animais foram submetidos a avaliações clínicas e radiológicas nos dias 8, 15, 30, 60, 120 e 180 de pós-operatório. Nas mesmas datas, dois animais de cada grupo foram sacrificados e deles colheu-se material para histologia. Observou-se evolução normal da regeneração óssea em todos os animais, sendo mais precoce nos dos grupos que receberam os compósitos. O uso de HAC e HACF na ulna de coelho mostrou-se um método eficiente, não apresentando sinais de infecção e nem evidência de rejeição.

Characterization of an immunoglobulin binding protein homolog in the maize floury-2 endosperm mutant.

The maize b-70 protein is an endoplasmic reticulum protein overproduced in the floury-2 (fl2) endosperm mutant. The increase in b-70 levels in fl2 plants occurs during seed maturation and is endosperm specific. We have used amino acid sequence homology to identify b-70 as a homolog of mammalian immunoglobulin binding protein (BiP). Purified b-70 fractions contain two 75-kilodalton polypeptides with pl values of 5.3 and 5.4. Both 75-kilodalton polypeptides share several properties with BiP, including the ability to bind ATP and localization within the lumen of the endoplasmic reticulum. In addition, both b-70 polypeptides can be induced in maize cell cultures with tunicamycin treatment. Like BiP, the pl 5.3 form of b-70 is post-translationally modified by phosphorylation and ADP-ribosylation. However, modification of the pl 5.4 species was not detected in vitro or in vivo. Although the b-70 gene is unlinked to fl2, b-70 overproduction is positively correlated with the fl2 gene and is regulated at the mRNA level. In contrast, the fl2 allele negatively affects the accumulation of the major endosperm storage proteins. The physical similarity of b-70 to BiP and its association with abnormal protein accumulation in fl2 endoplasmic reticulum may reflect a biological function to mediate protein folding and assembly in maize endosperm.

Increased expression of the maize immunoglobulin binding protein homolog b-70 in three zein regulatory mutants.

Plants carrying floury-2, Defective endosperm-B30, or Mucronate mutations overproduce b-70, a maize homolog of the mammalian immunoglobulin binding protein. During endosperm development in these mutants, levels of both b-70 protein and RNA increase dramatically between 14 days and 20 days after pollination. At later stages, b-70 RNA levels decline while protein levels remain high. The increase in b-70 RNA levels is endosperm specific and dependent on gene dosage in the floury-2 mutant. In all three mutants, the increases in b-70 RNA and protein levels are inversely proportional to changes in zein synthesis. Although b-70 polypeptides can be extracted from purified protein bodies, they carry a carboxy-terminal endoplasmic reticulum retention signal, HDEL. We propose that induction of b-70 in these mutants is a cellular response to abnormally folded or improperly assembled storage proteins and probably reflects its role as a polypeptide chain binding protein.