A novel ELISA for quantification of glycoprotein in human rabies vaccines using a clinically proven virus neutralizing human monoclonal antibody.

Global efforts on the replacement of the in vivo rabies vaccine potency test (NIH method) with in vitro methods for quantification of immunodominant glycoprotein (GP) in rabies vaccine have made significant progress. We report here, a sandwich ELISA method based on the use of a neutralizing rabies GP site III directed human monoclonal antibody (RAB-1) and a polyclonal GP specific antibody recognizing the intact form of viral GP. The method was shown to be robust, specific, linear, precise and accurate in the quantification of intact GP in vaccine samples. The assay was able to differentiate between potent and sub-potent vaccine samples. The assay was shown to be linear over the range of 0.07-2.25 IU/mL with LOD and LLOQ values of 0.035 and 0.070 IU/mL, respectively. The assay was able to quantify the GP content of rabies vaccines derived from rabies vaccine strains, e.g., Pittman-Moore, Pasteur and Flury LEP with acceptable precision (CV < 20%) and also showed good agreement with NIH potency estimates. The binding kinetics of RAB-1 with intact and modified vaccine samples were also characterized using biolayer interferometry (BLI). The developed method may be used as an alternative to the NIH method in quality control testing of human rabies vaccines.

Magnitude of peripheral neuropathy in cirrhosis of liver patients from central rural India.

CONTEXT: Cirrhosis of liver is an important cause of morbidity and mortality and if associated with peripheral neuropathy (PN) it also poses a huge financial, psychological burden for the patients and their families. AIM: The aim of the present study was to study the magnitude of PN among subjects with cirrhosis of liver presenting to tertiary care teaching hospital in central rural India. SETTINGS AND DESIGN: A cross-sectional study was performed in a tertiary care teaching hospital. MATERIALS AND METHODS: In all patients of cirrhosis of liver irrespective of etiology, aged 15 and above, undergone clinical assessment for peripheral nervous systems damage and confirmed by nerve conduction studies. STATISTICAL ANALYSIS USED: We used chi square test to study associations. P value ≤0.05 was considered as significant. Crude odds ratios were computed to assess the strength of association between independent variables and dependent variables along with their 95% confidence intervals. RESULTS: We included 207 of cirrhosis of liver patients admitted in medicine department from November 2010 through November 2013. Nearly 83% patients were male and 63.2% patients were under the age of 45 years. Common features in these patients were ascites (71%) splenomegaly (63.3%) pedal edema (61.4%) icterus (46.4%) tingling (44.9%) gastrointestinal bleeding(39.1%), ataxia (26.6%), numbness(26.6%), distal motor weakness (21.7%) and paresthesia(20.8%). Among the manifestation of peripheral nerve involvement, loss of ankle reflex was the most common feature in 51.7%, followed by loss of temperature sense 29.5%, loss of vibration sense 20.8%, loss of touch 16.4%, loss of position sense 14.5% and loss of pain in 6.3% of the patients. Peripheral neuropathy was found in 53.6% [95% CI: 46.58- 60.56] study subjects on electrophysiological study. CONCLUSIONS: Analysis of electrophysiological study shows that the PN is very common in study subjects with cirrhosis of liver, especially in male subjects, during the middle age group.

The study of diagnostic efficacy of nerve conduction study parameters in cervical radiculopathy.

BACKGROUND: Cervical Radiculopathy (CR) is a neurologic condition characterised by dysfunction of a cervical spinal nerve, the roots of the nerve, or both. Diagnostic criteria for CR are not well defined, and no universally accepted criteria for its diagnosis have been established. Clinical examination, radiological imaging and electrophysiologic evaluation are the different modalities to diagnose CR. The incidence of Cervical Spondylosis and related conditions is increasing in the present scenario and the use of radiologic examination is time consuming and uneconomical for the common Indian setup. Thus, there is a definite need to establish a cost effective, reliable, and accurate means for establishing the diagnosis of cervical radiculopathy. Electrodiagnostic tests are the closest to fulfill these criteria. AIM: To evaluate diagnostic utility of various motor and sensory nerve conduction study parameters in cervical radiculopathy. SETTING AND DESIGN: It was a cross-sectional study conducted on 100 subjects of age > 40 years. MATERIAL AND METHODS: The consecutive patients clinically diagnosed to have cervical radiculopathy, referred from department of Orthopaedics were prospectively recruited for the motor and sensory nerve conduction study using RMS EMG EP Mark-II. Parameters studied were Compound Muscle Action Potential (CMAP), Distal Motor Latency (DML) and Conduction Velocity (CV) for motor nerves and Sensory Nerve Action Potential (SNAP) and CV for sensory nerves. STATISTICAL ANALYSIS: Study observations and results were analysed to find the Specificity, Sensitivity, Positive Predictive Value and Negative Predictive Value using SPSS 16.0. RESULTS: Among various motor nerve conduction parameters CMAP was found to be more sensitive with high positive predicative value. CV was found to have greater specificity and DML had least negative predictive value. Sensory nerve conduction parameters were found to have less sensitivity but higher specificity as compared to motor parameters. CONCLUSION: Nerve conduction studies are useful supportive diagnostic tool for suspected cervical radiculopathy as they are found to have reliable sensitivity and specificity.