O desempenho e as respostas fisiológicas ao teste de elevação do calcanhar bipodal são influenciados pela cadência e posição dos tornozelos / Bilateral heel-rise test performance and physiological response are influenced by cadence and ankle position

INTRODUÇÃO: Diferentes protocolos do teste de elevação do calcanhar (TEC) têm sido utilizados, sendo necessário analisar o impacto das variações nas respostas do teste. OBJETIVO: Comparar o desempenho e respostas de oxigenação muscular (OM) e frequência cardíaca (FC) de adultos em diferentes protocolos do TEC bipodal. MATERIAIS E MÉTODOS: Este foi um estudo transversal do tipo cruzado. Trinta participantes (23,1±2,9 anos; 16 homens) realizaram quatro protocolos do TEC bipodal, variando cadenciamento (autocadenciado e cadenciado externamente) e posição dos tornozelos (neutra e dorsiflexão). Para a OM, analisamos a saturação tecidual de oxigênio (StO2 ) e variação da concentração de oxihemoglobina (∆[O2 Hb]) e calculamos a variação entre os menores valores e os valores finais (∆Nadir-Final) e área sob a curva (AUC). Para a FC, calculamos a variação dos valores iniciais e finais (∆FC) e constante de tempo (τ). O teste de Friedman foi utilizado para comparar as variáveis entre os protocolos. A ANOVA de dois fatores foi utilizada para identificar o impacto da cadência e/ou posição dos tornozelos. RESULTADOS: O número de repetições e o tempo de execução foram maiores nos protocolos em posição neutra e cadenciado externamente (p<0,001 para ambos). ∆Nadir-Final (StO2: p<0,001; ∆[O2Hb]: p=0,005) e AUC (StO2: p<0,001; ∆[O2Hb]: p<0,001) dea mbas as variáveis de OM foram maiores nos protocolos em posição neutra. Protocolos autocadenciados apresentaram maior aumento da FC e τ mais rápida (p=0,006 e p=0,046). CONCLUSÃO: O TEC realizado em posição neutra e cadenciamento externo gera maiores repetições e tempo de execução. A dorsiflexão promoveu menor reperfusão muscular e o autocadenciamento, maior e mais rápido aumento da FC.

INTRODUCTION: Different heel-rise test (HRT) protocols have been used, possibly leading to varied responses. It is necessary to analyse the impact of protocol variation on test responses. PURPOSE: To compare the performance, muscle oxygenation (MO), and heart rate (HR) responses of adults in bilateral HRT protocols. METHODS: This was a cross-sectional crossover study. Thirty participants (23.1±2.9 years; 16 men) performed four bilateral HRT protocols with varying cadence (self-cadenced; externally cadenced) and ankle position (neutral; dorsiflexion). For MO responses, we analysed tissue oxygen saturation (StO2) and oxyhemoglobin concentration variation (∆[O2Hb]) and calculated the variation between the smallest and final values (∆Nadir-Final) and the area under the curve (AUC). The variation between the initial and final HR values (∆HR) and the time constant (τ) were calculated. Friedman's test was used to compare the variables among the protocols. Two-way ANOVA was used to identify the impact of cadence and/or ankle position. RESULTS: The number of repetitions and execution time were higher in the neutral position and externally cadenced protocols (p<0.001 for both). ∆Nadir-Final (StO2: p<0.001;∆[O2Hb]: p=0.005) and AUC (StO2: p<0.001; ∆[O2Hb]: p<0.001) of both MO variables were higher in the neutral position protocols. Selfcadenced protocols presented higher HR increase and faster τ (p=0.006 and p=0.046). CONCLUSION: Bilateral HRT performed in a neutral position, and external cadence promotes more repetitions and a longer execution time. Dorsiflexion promotes lower muscle reperfusion, and self-cadence higher and faster HR increase.

A multi-component spectrophotometric method for simultaneous determination of total bilirubin, oxyhemoglobin, and methemalbumin in human sera

A new multi-component spectrophotometric method was developed experimentally and theoreticallyto determine the accurate serum concentrations of the total bilirubin (TB), oxyhemoglobin (HbO2), andmethemalbumin (Mha) in healthy human adults and neonates with hemolytic jaundice. With respect to theexperimental technique, the method of preparation of serum solution has been developed, like the use ofdistilled water as a solvent and centrifugation of serum solutions to clear the sample turbidity. The resultsof TB were compared to the diazo-assay. Theoretically, the formulas used for the calculation of the majorcomponents (TB, HbO2, and Mha) in human sera have been derived based on the theory of multi-componentspectrophotometric analysis and the mathematical Gaussian elimination method for matrix calculation. Themethod of multi-component spectrophotometry, suggested in this study for determination of TB, showed% error (3.1%–4.9%), indicating the high accuracy of the method. The small coefficients of variation(CV = 3.65%–5.1%) indicate the high precision of the method. The results showed higher values of serum TB(p < 0.00005), HbO2 (p < 0.001), and Mha concentrations (p < 0.00005) in neonates, when compared to adults.The method is highly sensitive and accurate. It is inexpensive, precise, reproducible, and has the advantages ofsimplicity, speed, and can be computerized.

Rattlesnake Crotalus molossus nigrescens venom induces oxidative stress on human erythrocytes

Background Globally, snake envenomation is a well-known cause of death and morbidity. In many cases of snakebite, myonecrosis, dermonecrosis, hemorrhage and neurotoxicity are present. Some of these symptoms may be provoked by the envenomation itself, but others are secondary effects of the produced oxidative stress that enhances the damage produced by the venom toxins. The only oxidative stress effect known in blood is the change in oxidation number of Fe (from ferrous to ferric) in hemoglobin, generating methemoglobin but not in other macromolecules. Currently, the effects of the overproduction of methemoglobin derived from snake venom are not extensively recorded. Therefore, the present study aims to describe the oxidative stress induced by Crotalus molossus nigrescens venom using erythrocytes. Methods Human erythrocytes were washed and incubated with different Crotalus molossus nigrescens venom concentrations (0-640 μg/mL). After 24 h, the hemolytic activity was measured followed by attenuated total reflectance-Fourier transform infrared spectroscopy, non-denaturing PAGE, conjugated diene and thiobarbituric acid reactive substances determination. Results Low concentrations of venom (<10 μg/mL) generates oxyhemoglobin release by hemolysis, whereas higher concentrations produced a hemoglobin shift of valence, producing methemoglobin (>40 μg/mL). This substance is not degraded by proteases present in the venom. By infrared spectroscopy, starting in 80 μg/mL, we observed changes in bands that are associated with protein damage (1660 and 1540 cm−1) and lipid peroxidation (2960, 2920 and 1740 cm−1). Lipid peroxidation was confirmed by conjugated diene and thiobarbituric acid reactive substance determination, in which differences were observed between the control and erythrocytes treated with venom. Conclusions Crotalus molossus nigrescens venom provokes hemolysis and oxidative stress, which induces methemoglobin formation, loss of protein structure and lipid peroxidation.(AU)

Rattlesnake Crotalus molossus nigrescens venom induces oxidative stress on human erythrocytes

Abstract Background Globally, snake envenomation is a well-known cause of death and morbidity. In many cases of snakebite, myonecrosis, dermonecrosis, hemorrhage and neurotoxicity are present. Some of these symptoms may be provoked by the envenomation itself, but others are secondary effects of the produced oxidative stress that enhances the damage produced by the venom toxins. The only oxidative stress effect known in blood is the change in oxidation number of Fe (from ferrous to ferric) in hemoglobin, generating methemoglobin but not in other macromolecules. Currently, the effects of the overproduction of methemoglobin derived from snake venom are not extensively recorded. Therefore, the present study aims to describe the oxidative stress induced by Crotalus molossus nigrescens venom using erythrocytes. Methods Human erythrocytes were washed and incubated with different Crotalus molossus nigrescens venom concentrations (0640 g/mL). After 24 h, the hemolytic activity was measured followed by attenuated total reflectance-Fourier transform infrared spectroscopy, non-denaturing PAGE, conjugated diene and thiobarbituric acid reactive substances determination. Results Low concentrations of venom ( 10 g/mL) generates oxyhemoglobin release by hemolysis, whereas higher concentrations produced a hemoglobin shift of valence, producing methemoglobin (>40 g/mL). This substance is not degraded by proteases present in the venom. By infrared spectroscopy, starting in 80 g/mL, we observed changes in bands that are associated with protein damage (1660 and 1540 cm1) and lipid peroxidation (2960, 2920 and 1740 cm1). Lipid peroxidation was confirmed by conjugated diene and thiobarbituric acid reactive substance determination, in which differences were observed between the control and erythrocytes treated with venom. Conclusions Crotalus molossus nigrescens venom provokes hemolysis and oxidative stress, which induces methemoglobin formation, loss of protein structure and lipid peroxidation.

Applications of functional near-infrared spectroscopy in clinical pediatric / 中华实用儿科临床杂志

Functional near-infrared spectroscopy is a non-invasive optical brain function detection technology,which can do multi-point measurement of changes on cerebral cortical area corresponding to the oxygenation of the blood hemoglobin and deoxygenated hemoglobin concentration,and then reflect the state of brain cortex function.Its greatest advantage is to allow the subjects head moving in a certain range,especially suitable for children.At present this technology could be applied to clinical pediatric,such as epilepsy,autism,attention deficit/hyperactivity disorder,neonatal disease,neurosurgery and cardiovascular surgery,etc.Functional near-infrared spectroscopy technology will have more applications in the field of research on brain function.

Effects of sildenafil on autonomic nervous function during sleep in obstructive sleep apnea

OBJECTIVE: To evaluate the effects of sildenafil on the autonomic nervous system in patients with severe obstructive sleep apnea. METHODS: Thirteen male patients with severe obstructive sleep apnea (mean age 43±10 years with a mean body mass index of 26.7±1.9 kg/m²) received a single 50-mg dose of sildenafil or a placebo at bedtime. All-night polysomnography and heart rate variability were recorded. Frequency domain analysis of heart rate variability was performed for the central five-minute sample of the longest uninterrupted interval of slow wave and rapid eye movement sleep, as well as for one-minute samples during apnea and during slow wave and rapid eye movement sleep after resumption of respiration. RESULTS: Compared to the placebo, sildenafil was associated with an increase in the normalized high-frequency (HFnu) components and a decrease in the low/high-frequency components of the heart rate variability ratio (LF/HF) in slow wave sleep (p<0.01 for both). Differences in heart rate variability parameters between one-minute post-apnea and apnea samples (Δ= difference between resumption of respiration and apnea) were assessed. A trend toward a decreasing magnitude of ΔLF activity was observed during rapid eye movement sleep with sildenafil in comparison to placebo (p=0.046). Additionally, Δ LF/HF in SWS and rapid eye movement sleep was correlated with mean desaturation (sR= -0.72 and -0.51, respectively, p= 0.01 for both), and Δ HFnu in rapid eye movement sleep was correlated with mean desaturation (sR= 0.66, p= 0.02) and the desaturation index (sR= 0.58, p = 0.047). CONCLUSIONS: The decrease in arousal response to apnea/hypopnea events along with the increase in HFnu components and decrease in LH/HF components of the heart rate variability ratio during slow wave sleep suggest that, in addition to worsening sleep apnea, sildenafil has potentially immediate cardiac effects in patients with severe obstructive sleep apnea.

The development of an OxyHb animal model in mice and the study on OxyHb-induced apoptosis of mouse brain cells in vivo / 药物分析学报

Objective On the basis of developing a new animal model for oxyhemoglobin (OxyHb) injection into subarachnoid space in mice, this research was to explore the temporal dependence and spatial distribution of OxyHb- induced apoptosis in the mouse brain cells in vivo and the mechanism of neurocyte injury induced by OxyHb. Methods The animal model for OxyHb injection into subarachnoid space in mice was developed. Mice were divided randomly into the experimental group (n=40) and the control group (n= 35). The control group received saline injection (50 μL ) and the experimental group received OxyHb injection (50 μL ), both into the subarachnoid space. The mice of the two groups were subdivided according to different postoperative time (3 h, 6 h, 12 h, 24 h and 48 h). The apoptosis or necrosis of cells was distinguished with microscopy (HE staining), transmission electron microscopy and TUNEL method. Results The distribution of apoptosis was mainly in the ipsilateral neocortex and bilateral hippocampal gyrus. The apoptotic mouse brain cells showed morphological changes in the experimental group by HE staining and transmission electron microscopy. The count of TUNEL-positive cells showed substantial increase in the experimental group, and there was a significant difference between the control and experimental groups, and the number of OxyHb- induced apoptotic cells decreased with time. Conclusion OxyHb in subarachnoid space in mice can induce apoptasis, but not necrosis of mouse brain cells in viro. The apoptotic brain cells show the pattern of temporal dependence and spatial distribution. It is suggested that the early treatment should be the method of first choice for treating the hemorrhagic brain injury.

Measurement of Penile Hemodynamics with Laser Oximetry in Rabbit Model / 대한남성과학회지

PURPOSE: This study was designed to determine the validity and usefulness of laser oximetry in measuring changes in penile hemodynamics for assessment of erectile function. MATERIALS AND METHODS: Anesthetized male New Zealand White rabbits (3.5~4.0 kg) were divided into two groups and penile hemodynamics were assessed by either laser oximetry (total hemoglobin, oxyhemoglobin, deoxyhemoglobin concentration and oxygen saturation) or intracavernosal pressure (ICP) monitoring before, during and after penile erection induced by pelvic nerve stimulation (PNS) or intracavernosal administration of phentolamine (0.05~1.0 mg/kg), nitroprusside (1~30ng/kg), papaverine (0.1~1.0 mg/kg) or sildenafil (3~150ng/kg). ICP recordings were normalized to systemic systolic arterial pressure. RESULTS: PNS caused significant frequency-dependent increases in penile ICP. PNS also caused significant increases in penile tissue hemoglobin (total and oxy) concentrations and tissue oxygen saturation in a frequency-dependent manner. These changes were correlated with frequency-dependent increases in ICP. The duration of recorded responses (changes in hemoglobin concentration or ICP) increased with increasing frequency of nerve stimulation. Intracavernosal administration of phentolamine, nitroprusside, papaverine and sildenafil produced significant increases in ICP, tissue hemoglobin, oxygen saturation and duration of response as a function of increasing drug concentration. CONCLUSIONS: Laser oximetry permits reproducible and valid assessment of changes in penile hemodynamics comparable to classical intracavernosal pressure measurements. Thus, we consider laser oximetry a reliable technique in evaluating penile hemodynamics. Its sensitivity in detecting small changes in oxyhemoglobin concentration and its non-invasive nature makes it advantageous over invasive METHODS such as intracavernosal pressure monitoring and laser Doppler flowmetry.

Measurement of Plasma Hemoglobin in Hyperbilirubinemia / 대한진단검사의학회지

BACKGROUND: Plasma hemoglobin has usually been determined by the spectrophotometric method of Harboe. This method is known to show interference by bilirubin and turbidity, although the method is easy. In order to correct the spurious increase of plasma hemoglobin concentration caused by hyper-bilirubinemia, we compared plasma hemoglobin assays by using various spectrophotometry methods and tried to select the method of minimal interference. METHODS: We performed five plasma hemoglobin assays based on spectrophotometry (Harboe, Noe, Kahn, Fairbanks 1, and Fairbanks 2) and three bilirubin assays (Fairbanks 1, Fairbanks 2, and bilirubin oxidase) on 100 patients without hemolysis and lipemia. RESULTS: The method of Kahn, et al. and the method 2 of Fairbanks, et al. of the plasma hemoglobinassay seemed to minimally interfere with the bilirubin. Only plasma oxyhemoglobin was measured by the method of Kahn, et al .; on the other hand, plasma hemoglobin and bilirubin could be measured one at a time by the method 2 of Fairbanks, et al. Method 1 of Fairbanks, et al. seemed to interfere extremely with bilirubin. CONCLUSIONS: Method 2 of Fairbanks, et al. is the first choice for the plasma hemoglobin assay considering the interference with bilirubin.

Blood P50 Calculated from a Single Measurement of pH, PO2 and SO2 under General Anesthesia / 대한마취과학회지

BACKGROUND: The P50 which is the oxygen tension corresponding to 50% saturation at pH 7.40, PCO2 40 mmHg and temperature 37oC is an accepted and useful reference to characterize the oxygen affinity for hemoglobin. This study evaluated the accuracy of P50 calculated from a single measurement of pH, PO2 and SO2 compared with linear regression and sigmoid Emax model in patients undergoing general anesthesia. This study also compared P50 of just after anesthetic induction to P50 of 90 min later. METHODS: This study was conducted in 10 patients undergoing total abdominal hysterectomy. Just after induction of anesthesia, 20G catheter was indwelled at cephalic vein of forearm and venous return was occluded with a tourniquet. After 4 min, 6 blood samples were obtained every one minute. After 90 min, 6 blood samples were obtained with same method. All blood samples were analyzed with blood gas analyzer within 30 min after withdrawal. P50 was calculated from three methods of calculation, linear regression and sigmoid Emax model. The difference between the actural P50 and calculated P50 was evaluated. RESULTS: P50's calculated from three methods were 25.8+/-1.1, 26.1+/-1.1, 26.0+/-1.2 mmHg respectively. P50's 90min after anesthetic induction (26.1+/-1.3, 26.3+/-1.2, 26.2+/-1.2 mmHg) were significantly greater than P50's just after anesthetic induction (25.5+/-0.8, 25.8+/-1.0, 25.9+/-1.1 mmHg)(P90%). Sigmoidicity of oxygen dissociation curves from 10 patients with sigmoid Emax model was 2.78+/-0.13 (mean SD). CONCLUSIONS: The method calculating P50 from a single measurement of pH, PO2, SO2 was relatively reliable to estimate the change of oxygen dissociation curve of a patient. The affinity of hemoglobin to O2 was reduced during general anesthesia.

The Effects of Intravenous Administration of Nimodipine on Cerebral Pial Vessels Following the Injection of Autogenous Hemolytic Blood into Cisterna Magna in Rabbits

The reactions of cerebral pial vessels following the injection of normal saline(0.05cc, at 37 degrees C, pH7.4) and autogenous hemolytic blood(0.05cc, 0.1cc 0.2cc) into the cisterna magna of rabbits were tested in vivo. This experiment was performed in order to observe the effect of intravenous nimodipine(30 microgram/kg) injection at the maximally constricted time of the pial vessels, about 6 hours after intracisternal injection of autogenous hemolytic blood. The diameter changes of the pial vessels were measured under operating microscope through a cranial window on craniectomized area. Pial vessels were not significantly changed after an intracisternal injection of normal saline. But after intracisternal injection of autogenous hemolytic blood(0.05cc, 0.1cc, 0.2cc), pial vessels were maximally constricted at 6 hours and the constriction was continued during the experiments. Percentile constriction was increased as the amount of subarachnoid hemolytic blood increased. According to the results, pial vessels, especially small pial artery, were constricted by autogenous hemolytic blood containing oxyhemoglobin. Nimodipine, calcium antagonist, showed dilating effect on vasospasm after experimental subarachnoid hemorrhage with autogenous hemolytic blood in rabbits.

Nocturnal Arterial Oxygen Saturation Monitoring in Patients with Respiratory Disease / 결핵

To find out the predictors of nocturnal arterial oxygen desaturation in patients with respiratory diseases, transcutaneous oxygen saturation(StcO2) monitoring studies using a pulse oximeter were performed during sleep in 20 patients. StcO2 was decreased more than 4% from the baseline value in 18 patients(90%) and more than 10%('Desaturator') in 8(40%). Five of the seven patients(71.4%) with awake PaO2<60mmHg and three of the thirteen patients(23.1%) with awake PaO2≥60mmHg were 'desaturators'. The awake PaO2/FIO2 and PaO2/PAO2 could distinguish 'desaturator' from 'nondesaturator, and PaO2, SaO2 or StcO2 could not. These results suggest that the nocturnal oxygen desaturation depends on the severity of the underlying disease rather than the baseline PaO2. Anthropomorphic and lung function factors could not separate between 'desaturator' and 'non-desaturator', and about a quarter of patients with a wake PaO2≥60mmHg developed significant desaturation. Therefore, it is necessary to monitor the nocturnal arterial oxygen saturation in patients with respiratory diseases regardless of their severity of airflow obstruction or awake PaO2.