Interplay of Oxidative Stress and Nitric Oxide Synthase Gene Expression on Cardiovascular Responses in Preeclampsia / Interação do estresse oxidativo e da expressão dos genes das óxido nítrico sintases nas respostas cardiovasculares na pré-eclâmpsia

Abstract Objective To assess the influence of oxidative stress on the gene expression of nitric oxide synthases (NOS 3 and NOS 2) and, hence, the cardiovascular responses in preeclampsia. Methods This was a case control study in which patients with preeclampsia (PE group) and normal pregnancy controls (NP group) were included according to the guidelines of the American College of Obstetricians and Gynecologists (ACOG). The serum levels of malondialdehyde (MDA), total antioxidant capacity, and nitric oxide (NO) were estimated, and the heart rate andmean arterial pressure were recorded. The gene profiling of NOS3 and NOS2 was performed through real-time polymerase chain reaction (RT-PCR). The statistical analysis was performed using the Student t-test, and values of p<0.05 were considered statistically significant. Results The serum levels of malondialdehyde were increased (p<0.0001), and the total antioxidant capacity was reduced in the PE group (p=0.034), indicating oxidative stress. In the PE group, themean arterial pressure was significantly higher (p<0.0001), but the serum levels of NO did not show a statistically significant reduction (p=0.20). The gene expression profiling of NOS3 and NOS2 revealed a down regulation in the PE group by 8.49 and 51.05 times respectively. Conclusion Oxidative stress may lead to endothelial dysfunction, which could result in increased mean arterial pressure. Nitric oxide may play a role in this mechanism, but interactions with other vasoactive /biological substances cannot be overlooked, as the gene expression of NOS3 and NOS2 has been reduced.

Resumo Objetivo Avaliar a influência do estresse oxidativo na expressão genética das óxido nítrico sintases (nitric oxide synthases, NOS, em inglês; NOS 3 e NOS 2) e, consequentemente, nas respostas cardiovasculares na pré-eclâmpsia. Métodos Este foi um estudo caso-controle no qual pacientes com pré-eclâmpsia (grupo PE) e controles comgravidez normal (grupo GN) foramincluídos de acordo com as diretrizes do American College of Obstetricians and Gynecologists (ACOG). Foram estimados os níveis séricos de malondialdeído (MDA) da capacidade antioxidante total, e de óxido nítrico (nitric oxide, NO, em inglês). A frequência cardíaca e a pressão arterial média foram registradas. O perfil genético da NOS3 e da NOS2 foi feito por reação em cadeia de polimerase em tempo real (real-time polymerase chain reaction, RT-PCR, em inglês). A análise estatística foi feita utilizando-se o teste t de Student, e valores de p<0,05 foram considerados estatisticamente significativos. Resultados Os níveis séricos de malondialdeído sérico estavam aumentados (p<0,0001), e a capacidade antioxidante total, reduzida no grupo PE (p=0,034), o que indicava estresse oxidativo. No grupo PE, a pressão arterial média era significativamente maior (p<0,0001), mas os níveis séricos de NO não demostraram redução estatisticamente significativa (p=0,20). O perfil de expressão genética da NOS3 e da NOS2 revelou uma regulação negativa no grupo PE de 8,49 e 51,05 vezes, respectivamente. Conclusão O estresse oxidativo pode levar à disfunção endotelial, o que pode resultar em aumento da pressão arterialmédia. O NO pode desempenhar umpapel neste mecanismo, mas as interações com outras substâncias vasoativas/biológicas não podem ser negligenciadas, uma vez que a expressão genética da NOS3 e da NOS2 foi reduzida.

Interplay of Oxidative Stress and Nitric Oxide Synthase Gene Expression on Cardiovascular Responses in Preeclampsia.

OBJECTIVE: To assess the influence of oxidative stress on the gene expression of nitric oxide synthases (NOS 3 and NOS 2) and, hence, the cardiovascular responses in preeclampsia. METHODS: This was a case control study in which patients with preeclampsia (PE group) and normal pregnancy controls (NP group) were included according to the guidelines of the American College of Obstetricians and Gynecologists (ACOG). The serum levels of malondialdehyde (MDA), total antioxidant capacity, and nitric oxide (NO) were estimated, and the heart rate and mean arterial pressure were recorded. The gene profiling of NOS3 and NOS2 was performed through real-time polymerase chain reaction (RT-PCR). The statistical analysis was performed using the Student t-test, and values of p < 0.05 were considered statistically significant. RESULTS: The serum levels of malondialdehyde were increased (p < 0.0001), and the total antioxidant capacity was reduced in the PE group (p = 0.034), indicating oxidative stress. In the PE group, the mean arterial pressure was significantly higher (p < 0.0001), but the serum levels of NO did not show a statistically significant reduction (p = 0.20). The gene expression profiling of NOS3 and NOS2 revealed a down regulation in the PE group by 8.49 and 51.05 times respectively. CONCLUSION: Oxidative stress may lead to endothelial dysfunction, which could result in increased mean arterial pressure. Nitric oxide may play a role in this mechanism, but interactions with other vasoactive /biological substances cannot be overlooked, as the gene expression of NOS3 and NOS2 has been reduced.

OBJETIVO: Avaliar a influência do estresse oxidativo na expressão genética das óxido nítrico sintases (nitric oxide synthases, NOS, em inglês; NOS 3 e NOS 2) e, consequentemente, nas respostas cardiovasculares na pré-eclâmpsia. MéTODOS: Este foi um estudo caso-controle no qual pacientes com pré-eclâmpsia (grupo PE) e controles com gravidez normal (grupo GN) foram incluídos de acordo com as diretrizes do American College of Obstetricians and Gynecologists (ACOG). Foram estimados os níveis séricos de malondialdeído (MDA) da capacidade antioxidante total, e de óxido nítrico (nitric oxide, NO, em inglês). A frequência cardíaca e a pressão arterial média foram registradas. O perfil genético da NOS3 e da NOS2 foi feito por reação em cadeia de polimerase em tempo real (real-time polymerase chain reaction, RT-PCR, em inglês). A análise estatística foi feita utilizando-se o teste t de Student, e valores de p < 0,05 foram considerados estatisticamente significativos. RESULTADOS: Os níveis séricos de malondialdeído sérico estavam aumentados (p < 0,0001), e a capacidade antioxidante total, reduzida no grupo PE (p = 0,034), o que indicava estresse oxidativo. No grupo PE, a pressão arterial média era significativamente maior (p < 0,0001), mas os níveis séricos de NO não demostraram redução estatisticamente significativa (p = 0,20). O perfil de expressão genética da NOS3 e da NOS2 revelou uma regulação negativa no grupo PE de 8,49 e 51,05 vezes, respectivamente. CONCLUSãO: O estresse oxidativo pode levar à disfunção endotelial, o que pode resultar em aumento da pressão arterial média. O NO pode desempenhar um papel neste mecanismo, mas as interações com outras substâncias vasoativas/biológicas não podem ser negligenciadas, uma vez que a expressão genética da NOS3 e da NOS2 foi reduzida.

PowerPoint presentation in learning physiology by undergraduates with different learning styles.

PowerPoint presentations (PPTs) have become routine in medical colleges because of their flexible and varied presentation capabilities. Research indicates that students prefer PPTs over the chalk-and-talk method, and there is a lot of debate over advantages and disadvantages of PPTs. However, there is no clear evidence that PPTs improve student learning/performance. Furthermore, there are a variety of learning styles with sex differences in classrooms. It is the responsibility of teacher/facilitator and student to be aware of learning style preferences to improve learning. The present study asked the following research question: do PPTs equally affect the learning of students with different learning styles in a mixed sex classroom? After we assessed students' predominant learning style according to the sensory modality that one most prefers to use when learning, a test was conducted before and after a PPT to assess student performance. The results were analyzed using Student's t-test and ANOVA with a Bonferroni post hoc test. A z-test showed no sex differences in preferred learning styles. There was significant increase in posttest performance compared with that of the pretest in all types of learners of both sexes. There was also a nonsignificant relationship among sex, learning style, and performance after the PPT. A PPT is equally effective for students with different learning style preferences and supports mixed sex classrooms.

Correlation Between Haemoglobin Level and Electrocardiographic (ECG) Findings in Anaemia: A Cross-Sectional Study.

BACKGROUND: Anaemia affects the body by decreased oxygen (O2) carrying capacity of the blood. There is growing evidence that anaemia contributes to cardiac disease and death. It causes O2 supply - demand myocardial mismatch causing myocardial ischemia. There is diversity of opinion available in literature on reports of electrocardiographic (ECG) changes in anaemia. AIM: To study the ECG changes in anemic population and to correlate ECG changes seen with increasing severity of anaemia. MATERIALS AND METHODS: In hundred anemic adults, haemoglobin level and resting ECG were recorded. They were grouped according to haemoglobin level. ECG findings and varying severity of haemoglobin (Hb) level of each group were correlated using Pearson 's co-relation co-efficient and association was calculated using Chi-square test. RESULTS: ECG changes in patients with Hb level of 0-5gm% showed ST segment depression in 50-75%, T wave changes in 29-50% and Left Ventricular Hypertrophy (LVH) in 25-30% of patients. Less percentage of patients with 5-7gm% Hb showed such changes, and patients with 7-8gm% Hb, showed no changes. As the Hb level decreased there was more percentage of patients having tachycardia and ECG changes. There was a strong negative correlation between Hb level and tachycardia and ECG changes. CONCLUSION: Diagnosing anaemia in critical care can be supported by ECG changes like ST depression, T wave changes, with/without associated QRS abnormalities to avoid misdiagnosis and also as dramatic clinical and ECG recovery can be achieved with anaemia correction.

Effect of yogic bellows on cardiovascular autonomic reactivity.

CONTEXT: Yoga is an ancient science, which originated in India. Pranayama has been assigned a very important role in yogic system of exercises. It is known that regular practice of breathing exercises (pranayama) increases parasympathetic tone, decreases sympathetic activity, and improves cardiovascular functions. Different types of breathing exercises alter autonomic balance for good by either decrease in sympathetic or increase in parasympathetic activity. Mukh Bhastrika (yogic bellows), a type of pranayama breathing when practiced alone, has demonstrated increase in sympathetic activity and load on heart, but when practiced along with other types of pranayama has showed improved cardiac performance. AIM: The present study was conducted to evaluate the effect of long term practice of fast pranayama (Mukh Bhastrika) on autonomic balance on individuals with stable cardiac function. SETTINGS AND DESIGN: This interventional study was conducted in the department of physiology. MATERIALS AND METHODS: 50 healthy male subjects of 18 - 25 years age group, fulfilling the inclusion and exclusion criteria underwent Mukh Bhastrika training for 12 weeks. Cardiovascular autonomic reactivity tests were performed before and after the training. STATISTICAL ANALYSIS USED: The parameters were analyzed by Student t test. RESULTS: This study showed an increase in parasympathetic activity i.e., reduced basal heart rate, increase in valsalva ratio and deep breathing difference in heart rate; and reduction in sympathetic activity i.e., reduction in fall of systolic blood pressure on posture variation. CONCLUSION: It can be concluded that Mukh Bhastrika has beneficial effect on cardiac autonomic reactivity, if practiced for a longer duration.

Effect of short-term pranayama and meditation on cardiovascular functions in healthy individuals.

CONTEXT: Asana, pranayama, and meditation are three main techniques of yoga practiced in India over thousands of years to attain functional harmony between the body and mind. Recent studies on long-term yogic practices have shown improvements in cardiovascular functions. AIM: The present study was conducted to ascertain if a short-term practice of pranayama and meditation had improvements in cardiovascular functions in healthy individuals with respect to age, gender, and body mass index (BMI). SETTINGS AND DESIGN: This interventional study was conducted in the Department of physiology of S.N. Medical College, Bagalkot. PATIENTS AND METHODS: Fifty healthy subjects (24 males and 26 females) of 20-60 years age group, fulfilling the inclusion and exclusion criteria underwent two hours daily yoga program for 15 days taught by a certified yoga teacher. Pre and post yoga cardiovascular functions were assessed by recording pulse rate, systolic blood pressure, diastolic blood pressure, and mean blood pressure. STATISTICAL ANALYSIS USED: The parameters were analyzed by Student's t test. RESULTS: There was significant reduction in resting pulse rate, systolic blood pressure, diastolic blood pressure, and mean arterial blood pressure after practicing pranayama and meditation for 15 days. The response was similar in both the genders, both the age groups, <40 yrs and >40 yrs and both the groups with BMI, <25 kg/m(2) and >25 kg/m(2). CONCLUSION: This study showed beneficial effects of short term (15 days) regular pranayama and meditation practice on cardiovascular functions irrespective of age, gender, and BMI in normal healthy individuals.

Anthropometry and physical fitness in individuals with family history of type-2 diabetes mellitus: A comparative study.

CONTEXT: The risk of becoming a diabetic for an individual with a positive family history of diabetes increases by two- to fourfold. AIM: To record the anthropometric indices and the physical fitness in individuals with family history of type-2 diabetes mellitus and compare these results with those of controls. SETTINGS AND DESIGN: This is a comparative study done in the department of physiology. MATERIALS AND METHODS: Thirty-two apparently healthy medical students with family history of type-2 Diabetes Mellitus were chosen for the study and matched with equal number of controls. Anthropometric measurements (height, weight, waist circumference, hip circumference, thigh circumference, upper segment and lower segment) were recorded. Body mass index (BMI), waist-hip ratio (WHR), waist-thigh ratio (WTR), and upper to lower segment ratio (US/LS ratio) were calculated. Blood pressure and heart rate were measured. Physical fitness was evaluated using Queen's College step test protocol. Rate Pressure Product (RPP) and Physical Fitness Index (PFI) were calculated before and after exercise. STATISTICAL ANALYSIS: Statistical analysis was done using SPSS software. RESULTS: BMI, WHR, US/LS ratio, and RPP at rest were significantly higher (P < 0.05), whereas WTR, PFI, and RPP after exercise lower (P > 0.05) in cases as compared to controls. CONCLUSIONS: It can be concluded that apparently healthy individuals with family history of type-2 diabetes mellitus have higher anthropometric values and lower physical fitness than the controls.

Suboccipital retrosigmoid surgical approach for internal auditory canal--a morphometric anatomical study on dry human temporal bones.

Suboccipital retrosigmoid craniotomy with removal of posterior wall of internal auditory canal is preferred by many surgeons operating on acoustic neuromas, as it is a simple and safe approach. To study the topographic landmarks of the posterior surface of the temporal bone. We studied the surgical anatomy of 224 dry adult human temporal bones, measured the various distances on posterior wall of petrous bone relevant for suboccipital surgical approach to internal auditory canal. The internal auditory canal (IAC) lies within 32-44 mm from posterior wall of sigmoid sulcus and within 3-8 mm from the superior border of petrous bone. The point corresponding to highest point of jugular bulb was found between 4 and 9 mm away from the inferior border of IAC. The maximum distance found between bony orifice of vestibular aqueduct and IAC was 14 mm and the minimum distance was 6 mm.The vertical diameter of IAC ranged between 3 and 7 mm. These parameters may help the surgeons for better exposure of internal auditory canal and for avoiding damage to vital surrounding structures.

A study of electrocardiographic changes in congenital deaf school children.

BACKGROUND: There is evidence of cardiac abnormalities in congenital deaf school children, together called as Jervel Lange Nielsen syndrome or Long QT syndrome. AIM: The main aim was to study the electrocardiographic changes in congenital deaf children. MATERIALS AND METHODS: Fifty congenital deaf children aged 6-18 years were selected. ECG was taken in lead II, at rest and after exercise, as some are known to exhibit the abnormality after exercise. The child was made to run on the Tread mill till exhaustion. Corrected QT interval (QTc) was Calculated by Bazett's formula QTc = QT/ √R-R. ECG was also analyzed for other abnormalities like Twave changes, ST depression, rhythm abnormalities etc. RESULTS: Out of 50, 2 children showed resting QTc of 0.45 sec which is diagnostically high. Mean value of QTc in deaf children(Cases) before exercise was 0.4111 ± 0.0271 sec and in controls 0.379 ± 0.020 sec. Mean value of QTc after exercise in deaf(cases) was 0.403 ± 0.028 sec and in controls 0.376 ± 0.021 sec. Eight deaf children showed ST depression and 2 biphasic T and 2 notched T waves. Thirty-three deaf children's parents had consanguineous marriage. CONCLUSION: The results were explained on the basis of ion channellopathy in heart and inner ear which predisposes to sensorineural hearing loss and cardiac abnormality.