Effect of chronic restraint stress on immune status of male Sprague Dawley rats.

OBJECTIVE: To determine the effect of chronic restraint stress on immune status of Sprague Dawley rats by comparing total leukocyte count (TLC), total lymphocyte count and levels of serum immunoglobulins A, E, G and M of the rats exposed to chronic restraint stress with that of healthy control rats. STUDY DESIGN: Quasi-experimental study. PLACE AND DURATION OF STUDY: Centre of Research in Experimental and Applied Medicine (CREAM), Army Medical College, Rawalpindi, in collaboration of National Institute of Health (NIH), Islamabad, from June 2008 to June 2009. METHODOLOGY: Sixty healthy male Sprague Dawley rats were obtained from NIH. Rats were divided into two groups, each having 30 rats. The rats of group-I were not exposed to chronic restraint stress, while rats of group-II were exposed to chronic restraint stress in meshwire restrainer for 6 hours daily for 15 days. Estimation of total lymphocyte count and serum immunoglobulins (IgG, IgA, IgM and IgE) was carried out and compared between the groups. RESULTS: TLC, lymphocyte count and serum IgA, IgE, IgG and IgM levels were found significantly lower in rats exposed to chronic restraint stress as compared to the rats which were not exposed to stress (p < 0.001). CONCLUSION: Chronic restraint stress compromises immune status of rats by decreasing the levels of immunoglobulins and lymphocyte count.

Effect of ascorbic acid and alpha tocopherol on immune status of male Sprague Dawley rats exposed to chronic restraint stress.

BACKGROUND: The immune system provides protection against infectious diseases or other insults. Psychological stress may alter antibody production through neurobiological pathways. Antioxidant supplementation is thought to improve immune status and thereby reduce infectious morbidity. The aim of this study was to determine the preventive effect of ascorbic acid and alpha tocopherol on immune status of rats exposed to chronic restraint stress. METHODS: A total of 150 healthy male Sprague Dawley rats were included in the study. They were divided into 5 groups, each comprised of 30 rats. Group I was the control group on normal diet. Group II rats were exposed to chronic restraint stress for 6 hours daily for 15 days, without antioxidant supplementation, whereas rats of groups III, IV and V were given supplementation of ascorbic acid or alpha tocopherol or both respectively, for one month prior to exposure of rats to chronic restraint stress. Total leukocyte count (TLC) and lymphocyte counts was done, and serum immuno-globulins (IgG, IgA, IgM, and IgE) levels were estimated using ELISA. RESULTS: Total leukocyte and lymphocyte counts and serum IgA, IgE, IgG, and IgM levels were found significantly (p 0.001) decreased in rats exposed to chronic restraint stress compared to the rats not exposed to the restraint stress. The combined supplementation of ascorbic acid and alpha tocopherol significantly (p 0.001) prevented the decline in total leukocyte and lymphocyte counts and serum immuno-globulins compared to the administration of either of the two antioxidants. CONCLUSION: Antioxidants (ascorbic acid and alpha tocopherol) given in combination produce greater beneficial effect in improving the immune status of rats exposed to chronic stress than individual supplementation of either ascorbic acid or alpha tocopherol.

Variable response to inhaled nitric oxide in postoperative patients of mitral stenosis with pulmonary hypertension.

BACKGROUND: This study was carried out to determine the vasodilator response of inhaled nitric oxide in patients with pulmonary hypertension (PH) after valve replacement surgery for mitral valve disease. METHOD: This Quesi experimental study was carried out at the intensive care unit of Armed Forces Institute of Cardiology (AFIC) in collaboration with Department of Physiology, Army Medical College, Rawalpindi from March 2004 to February 2006. Thirty patients with systolic Pulmonary Artery Pressure (PAP) > 50 mmHg on pre-operative echocardiography were inducted. Swan Ganz catheter was inserted to record baseline pulmonary artery pressure and pulmonary capillary wedge pressure (PCWP), while cardiac output (CO) was recorded through lithium dilution method. Pulmonary Vascular Resistance (PVR) was calculated with the help of a formula. Inhaled nitric oxide (iNO) was administered after the surgery and the same parameters were recorded again after one hour. RESULTS: The majority of patients were females (73%), while males were only 27%. Out of 30, 21 had isolated mitral stenosis and 9 had mixed mitral and aortic valve disease. 22 patients responded significantly to iNO therapy with > or = 40.0% reduction in their baseline PVR while 8 patients showed insignificant improvement in their PVR (663 +/- 233 dynes.sec.cm(-5) to 605 +/- 222 dynes.sec.cm(-5)). CONCLUSION: Significant improvement in pulmonary vascular resistance in the responders and maintenance of high pressures despite iNO therapy in non-responders indicate that apart from some abnormality in nitric oxide pathway, some other factors may be a contributing in the causation of PH secondary to mitral stenosis in adults, which warrant further studies.

Hyperventilatory capacity--a predictor of altitude sickness.

BACKGROUND: The aim of the study was to document link between hyperventilatory capacity and risk for developing acute mountain sickness (AMS). METHODS: This study was carried out at Karakorum Mountain ranges (Northern areas of Pakistan) from March till July 2004. 54 healthy male subjects were enrolled in this study. Arterial oxygen saturation (SpO2) of the subjects was measured by the pulse oximeter at rest and after 1 minute of voluntary hyperventilation at an altitude of 2833 meters. Symptoms of acute mountain sickness (AMS) were recorded on a questionnaire by using the Lake Louise consensus scoring system 24 hours after ascent to high altitude. RESULTS: Mean pre hyperventilation oxygen saturation (SpO2) was 94.07 + 0.26% whereas SpO2 after 01 minute of hyperventilation was 98.61 + 0.14% that was significantly increased (p<0.001). The mean increase in percent oxygen saturation of hemoglobin after one minute of hyperventilation (hyperventilatory capacity) for the study group was 4.61 +/- 0.24 % while the mean symptom score was 2.06 +/- 0.26. It was noted that 19 (35.2%) subjects did not develop AMS whereas 34(63.0%) subjects had mild AMS and only one subject developed moderate AMS. There was no case of severe AMS. The data reveals significant (P<0.01) association between hyperventilatory capacity and development of the symptoms of AMS (r = -0.664). It is evident that individuals with greater hyperventilatory capacity manifest less number of symptoms of mountain sickness. CONCLUSION: It is concluded that post hyperventilation increase in oxygen saturation at lower altitude may help to predict the susceptibility of subjects to develop high altitude sickness.

Correlation of eosinophil cationic protein with severity of asthma.

BACKGROUND: Activated eosinophils play an important role in the pathogenesis of bronchial asthma. Upon activation eosinophils release their granular proteins. Eosinophil Cationic Protein (ECP) is a highly basic protein of ribonuclease-A family that is released from matrix of eosinophil granules. In the recent past a number of studies have shown increased levels of ECP in serum and induced sputum of asthmatics. We carried out this study to find out correlation of serum ECP with severity of asthma. METHODS: This study was carried out on 44 asthmatics and 44 matched controls at Department of Physiology, Army Medical College, Rawalpindi from June 2002 to December 2003. Lung function tests were done using spirometer (Vitalograph-Compact) and severity of asthma was graded into four classes, mild intermittent, mild persistent, moderate persistent and severe persistent. Serum was used to assess ECP by ELISA. Statistical correlation between ECP and severity of asthma as well as lung function tests was calculated. RESULTS: The asthmatics as compared with the controls had significantly more serum ECP. Serum ECP increased significantly with increase in severity of asthma (from mild intermittent to severe persistent). Serum ECP was negatively correlated with FEV1 and FEV1/FVC(r=-.823 and r=-.772. p<.001 respectively). There was a significant positive correlation between serum ECP and severity of asthma (r=0.947 p<0.001) CONCLUSIONS: We conclude from this study that serum ECP can be used as a useful laboratory investigation for severity of asthma.

Eosinophils and eosinophil products in asthma.

Eosinophils are known to be an indirect marker of airway inflammation in asthma. It is known since long that the total eosinophil count reflects asthmatic activity and is useful for regulating steroid dosage and for early detection of exacerbations. Eosinophils are currently regarded as the effector cells responsible for much of the pathology of asthma. Eosinophil-mediated damage to the respiratory epithelium is a major pathogenetic mechanism in asthma. This article is a review of the latest works about the relationship of eosinophil and eosinophil products with asthma.