[Preparation of a block copolymer-based temperature-responsive affinity chromatography stationary phase for antibody separation and purification].

Antibodies play an essential role in cancer diagnosis and treatment because of the specificity for target biomolecules and reduction of side effects. However, antibodies separation and purification still face some challenges. Antibody elution from columns using a low-pH aqueous solution leads to aggregation or loss of activity of the antibody drugs. In this paper, a block copolymer-based temperature-responsive affinity chromatography (TRAC) stationary phase, SiO2-P[NIPAM-b-4VP]-MEP using the block temperature-responsive copolymer poly(N-isopropylacrylamide-b-4-vinylpyridine) (P[NIPAM-b-4VP]) as the space arms and 4-mercaptoethyl pyridine (MEP) as the ligand was prepared for antibody separation. The TRAC column was tested using bovine serum albumin (BSA) and γ-globulin as model proteins, and the effects of salt concentration in the mobile phase and temperature on their separation were studied in detail. At 40 ℃, the TRAC stationary phase only selectively retained γ-globulin due to the specific affinity interaction between antibodies and the ligand MEP. At 5 ℃, γ-globulin can be eluted from the column with a mass recovery of 92.7% using a Tris-HCl buffer (pH 8.0) solution containing 0.6 mol/L NaCl. The adsorption capacity of γ-globulin on this stationary phase was (71.5 ±2.1) mg/g (n=3), which was twice that of a traditional temperature-sensitive affinity chromatography stationary phase SiO2-PNIPAM-MEP. The stationary phase was also used to separate and purify immunoglobulin (IgG) in human serum in one step by altering the temperature and ion strength of the mobile phase, resulting in a purity of 97.4%±0.7%. Thus, this new technology has specific selectivity for antibodies, as well as mild and green elution conditions, ultimately resolving the problem of traditional affinity chromatography using acid elution, which can lead to the antibodies aggregation/inactivation. This technology has great application potential for the industrial production of antibody drugs.

Reliability of the neurological scores for assessment of sensorimotor neuropathy in type 2 diabetics.

OBJECTIVE: To check the reliability of the commonly used neurological scoring systems taking the nerve conduction studies as the reference. METHODS: Diagnosed diabetics (n=60) were selected by purposive sampi ng Detection and grading of neuropathy were done according to Diabetic Neuropathy Symptom Score (DrNS), modified Neuropathy Symptom Score (NSS), Diabetic Neuropathy Examination (DNE) and modified Neuropathy Disability Score (NDS). For the nerve conduction studies, amplitudes, velocities and latencies of minimum two (Sural, Peroneal) and maximum six, i.e., three sensory (Sural, Ulnar, Median) and three motor (Peroneal, Ulnar, Tibial) nerves were checked. If the patient had 2 or more than two abnormal findings in any of the nerve he was labeled to have peripheral sensorimotor neuropathy. Later the sensitivity, specificity and diagnostic efficacy of each neurological score was checked taking nerve conduction studies as the gold standard. RESULTS: Taking the NCS as gold standard DNS, DNE, NSS and NDS had 64.1%, 17.95%, 82.05%, 92.31% sensitivity and 80.95%, 100%, 66.67%, 47.62% specificity, respectively. Diagnostic efficacy of DNS was 70%, DNE was 47%, NSS was 77% and NDS was 77%. CONCLUSIONS: Combining different scores gives better sensitivity and specificity. NDS is the most reliable neurological test for detecting and grading DPN.

Comparison of nerve conduction studies with diabetic neuropathy symptom score and diabetic neuropathy examination score in type-2 diabetics for detection of sensorimotor polyneuropathy.

OBJECTIVE: To compare the nerve conduction studies in clinically undetectable and detectable sensorimotor polyneuropathy in type 2 diabetics. METHODS: Diagnosed diabetics (n = 60) were divided in two groups. Group 1 (n1 = 30) with clinically undetectable and group 2 (n2 = 30) with clinically detectable Diabetic Polyneuropathy. Detection of the sensorimotor neuropathy was done according to Diabetic Neuropathy Symptom Score and Diabetic Neuropathy Examination scores. The simplified nerve conduction studies protocol was followed in recording amplitudes, velocities and latencies of minimum two (Sural, Peroneal) and maximum six i.e. three sensory (Sural, Ulnar, Median) and three motor (Peroneal, Ulnar, Tibial) nerves. RESULTS: The comparisons were done between different parameters of nerve conduction studies with the neurological scores in undetectable and detectable groups using Pearson's chi square test. The amplitudes, velocities, latencies, outcome and grading of neuropathy in nerve conduction studies when compared with neurological detection scores showed a significant relation in each group regarding evaluation (p = 0.005, p = 0.004, p = 0.05, p = 0.00001, p = 0.003 respectively). CONCLUSIONS: Diabetic Neuropathy Symptom Score and Diabetic Neuropathy Examination Score together can help in prompt evaluation of the diabetic sensorimotor polyneuropathy though nerve conduction study is more powerful test and can help in diagnosing subclinical cases.