Nerve conduction study in young children suffering from cerebral palsy

Objectives: Cerebral palsy (CP) is a motor impairment syndrome leading to disorders of movement and posture. Screening of electrophysiological parameters Hoffman reflex (H-reflex and nerve conduction velocities) becomes a necessary for the early detection and management of the disease. The study aimed to assess the various electrophysiological parameters of nerve conduction velocity in CP and age-matched normal children. Matrials and Methods: The present cross-sectional study was performed between children suffering from CP and healthy control. A total of 27 children of 12–24 months of age of either sex were examined. Among them, six children were normal (with age match), seven were diagnosed with spastic CP and remaining 14 children were diagnosed with hypotonic CP The electrophysiological parameters were recorded in the right lower limb (posterior tibial nerve-soleus muscle) of all children. Results: In electrophysiological parameters, H-reflex latency in secs values was significantly decreased in all CP children. The maximum amplitudes of reflexly excitable motor neurons (Hmax) (mV) and Hmax/maximum amplitude of motor response ratio in the gastrocnemius-soleus muscle were significantly increased in spastic CPas compared to control. H-reflex conduction velocity (HRCV) was significantly higher than motor nerve conduction velocity (MNCV) in hypotonic CP children. Conclusion: The electrophysiological parameters were altered in spastic CP children. The electrophysiological parameters in hypotonic CP were within range, indicating they did not suppress the neuronal motor pool. However, HRCV was significantly more than MNCV in hypotonic CP, suggesting some myelination process defect/white matter injury in motor neurons. We concluded that the electrophysiological parameters of the nerve conduction study are a reliable test for the assessment of tone of muscles in children. Thus, it may help in the early initiation of the treatment and therapies in CP children.

Indomethacin Exacerbates Oleic Acid-Induced Acute Respiratory Distress Syndrome in Adult Rats.

Acute respiratory distress syndrome (ARDS) is an acute fulminant condition associated with acute lung injury and inflammation leading to hypoxemia, pulmonary edema and respiratory failure. Even though prostaglandins are inflammatory mediators, the role of prostaglandins in ARDS is still not clear. Therefore, we examined the involvement of prostaglandin in experimentally induced ARDS by using prostaglandin synthesis inhibitor, indomethacin. Experiments were conducted on anesthetized adult rats (total n=15). Cannulation of trachea, jugular vein and carotid artery was done in these rats. Recording of respiratory excursions (for respiratory frequency; RF), ECG (for heart rate; HR) and blood pressure, before and after lethal dose of oleic acid (75 µL i.v.) was done for 120 min or till death of the animals. Arterial blood sample was collected 15 min after oleic acid injection to determine PaO2/FiO2 ratio. Lungs were excised at the end of experiment for estimation of pulmonary water content. Administration of oleic acid produced progressive increase in the RF up to 45 min followed by decrease. Subsequently, the respiration stopped and all the animals died by 75 min (mean survival time = 64±8.2 min). HR and mean arterial pressure (MAP) exhibited an immediate decrease followed by an increase up to 45 min. Thereafter, the HR and MAP progressively decreased. PaO2/FiO2 ratio in this group was 182±2.6 mm Hg and pulmonary water content was significantly greater than saline control group. However in indomethacin pretreated rats, injection of oleic acid produced instantaneous decrease in RF and all the animals died within 10 min (mean survival time = 6.6±1.07 min). HR and MAP followed the same pattern as seen with RF. Pulmonary water content in indomethacin pretreated animals was also significantly greater than control group. These observations indicate that indomethacin exacerbates the OA-induced ARDS. Thus, prostaglandins play an important role in the pathophysiology of OA-induced ARDS.

Characterization of oleic acid-induced acute respiratory distress syndrome model in rat.

Animal studies using oleic acid (OA) model to produce acute respiratory distress syndrome (ARDS) have been inconsistent. Therefore, the present study was undertaken to establish an acute model of ARDS in rats using OA and to characterize its effect on cardio-respiratory parameters and lethality. The trachea, jugular vein and femoral artery of anesthetized adult rats were cannulated. A dose of OA (30-90 µL; iv) was injected in each animal and changes in respiratory frequency (RF), heart rate (HR) and mean arterial pressure (MAP) were recorded. Minute ventilation and PaO2/FiO2 (P/F) ratio were also determined. At the end, lungs were excised for determination of pulmonary water content and histological examination. At all doses of OA, there was immediate decrease followed by increase in RF, however at 75 and 90 µL of OA, RF decreased abruptly and the animals died by 63 ± 8.2 min and 19 ± 6.3 min; respectively. In all the groups, HR and MAP changes followed the respiratory changes. The minute ventilation increased in a dose-dependent manner while the values of P/F ratio decreased correspondingly. Pulmonary edema was induced at all doses. Histological examination of the lung showed alveolar damage, microvascular congestion, microvascular injury, infiltration of inflammatory cells, pulmonary edema and necrosis in a dose-dependent manner. With these results, OA can be used to induce different grades of ARDS in rats and OA doses of 50, 60 and 75 µL resemble mild, moderate and severe forms of ARDS respectively. Hence, OA model serves as a useful tool to study the pathophysiology of ARDS.

Aprotinin reverses ECG abnormalities induced by Mesobuthus tamulus concanesis, Pocock venom in adult rats.

The kinins are implicated in the pathogenesis of scorpion envenomation. Therefore, this study was carried out to examine the involvement of kinins for the ECG abnormalities induced by M. tamulus concanesis, (BT) venom in anaesthetized rats. ECG was recorded using needle electrodes with limb lead II configuration. The PR interval, QRS wave pattern, QRS duration, ST segment and heart rate were examined in saline only, venom alone, and venom after aprotinin groups. BT venom (5 mg/kg) produced heart block of varying degree and ischemia-like changes in ECG wave pattern and the animals died within 30 min after exposure to venom. In aprotinin pretreated animals, the initial ECG changes produced by venom persisted, but after 15 min the ECG pattern improved and the animals survived for the entire period of observation (120 min). The results indicate that aprotinin protected the rats against the cardiotoxicity induced by BT venom.