Development of new lateral-flow immunochromatographic strip using colloidal gold and mesoporous silica nanoparticles for rapid diagnosis of active schistosomiasis

Objective: To develop a new sandwich based lateral flow immunochromatographic strip for rapid detection of circulating Schistosoma mansoni antigen in serum and urine samples of patients with active schistosomiasis. Methods: This lateral flow immunochromatographic strip was prepared by using anti-Schistosoma mansoni soluble egg antigen monoclonal antibody conjugated gold nanoparticles (MAb-AuNPs) as antigen-detecting antibody, while crystalline material (MCM)-41-MAb bioconjugate was immobilized at the test line as antigen-capturing antibody. Both antigen capturing and detecting antibodies formed sandwich complexes with circulating Schistosoma mansoni antigen in the positive samples. Sandwich complexes immobilized at the test line gave distinct red color. The assay reliability was examined by using urine and serum samples of 60 Schistosoma mansoni infected patients, 20 patients infected with parasites other than Schistosoma, and 20 healthy individuals as negative controls. Results were compared with those obtained via sandwich enzyme linked immunosorbent assay (ELISA). Results: The detection limit of circulating Schistosoma mansoni antigen by lateral flow immunochromatographic strip was lower (3 ng/mL) than the detection limit by ELISA (30 ng/mL). The sensitivity and specificity of lateral flow immunochromatographic strip in urine samples were 98.3% and 97.5%, respectively compared to 93.5% and 90.0% by ELISA. In serum samples, they were 100.0% and 97.5%, respectively compared to 97.0% and 95.0% by ELISA. The strip test took approximately 10 min to complete. Conclusions: This new lateral flow immunochromatographic strip offers a sensitive, rapid, and field applicable technique for diagnosis of active schistosomiasis.

Monoclonal Antibody-Based Dipstick Assay: A Reliable Field Applicable Technique for Diagnosis of Schistosoma mansoni Infection Using Human Serum and Urine Samples

A field applicable diagnostic technique, the dipstick assay, was evaluated for its sensitivity and specificity in diagnosing human Schistosoma mansoni infection. A monoclonal antibody (mAb) against S. mansoni adult worm tegumental antigen (AWTA) was employed in dipstick and sandwich ELISA for detection of circulating schistosome antigen (CSA) in both serum and urine samples. Based on clinical and parasitological examinations, 60 S. mansoni-infected patients, 30 patients infected with parasites other than schistosomiasis, and 30 uninfected healthy individuals were selected. The sensitivity and specificity of dipstick assay in urine samples were 86.7% and 90.0%, respectively, compared to 90.0% sensitivity and 91.7% specificity of sandwich ELISA. In serum samples, the sensitivity and specificity were 88.3% and 91.7% for dipstick assay vs. 91.7% and 95.0% for sandwich ELISA, respectively. The diagnostic efficacy of dipstick assay in urine and serum samples was 88.3% and 90.0%, while it was 90.8% and 93.3% for sandwich ELISA, respectively. The diagnostic indices of dipstick assay and ELISA either in serum or in urine were statistically comparable (P>0.05). In conclusion, the dipstick assay offers an alternative simple, rapid, non-invasive technique in detecting CSA or complement to stool examinations especially in field studies.

Use of dexamethasone in cerebral oedema

Dexamethasone is prescribed routinely to reduce cerebral oedema in neurosurgical patients undergoing craniotomy for tumour .Dexamethasone, however, has been shown to cause hyperglycaemia. We describe a case of hyperglycaemic crisis, cerebral oedema secondary to dexamethasone in a patient with a Right temporal meningioma. We highlight the risks of pre-operative dexamethasone and discuss the diagnosis, treatment and complications of hyperglycaemic crises and diabetic ketoacidosis

Mediastinal ganglioneuroblastoma-secreting vasoactive intestinal peptide causing secretory diarrhea

In this case report we describe a case of mediastinal ganglioneuroblastoma-secreting vasoactive intestinal peptide [VIP], causing secretory diarrhoea in an 18-month-old child. An 18-month-old girl presented with a 2-month history of diarrhoea, abdominal distension and weight loss. Investigations revealed secretory diarrhoea with hypokalaemia, hyponatraemia and hypochloraemia and metabolic acidosis. Her stool output was 2.5-3.1 day[-1] with increased stool sodium. VIP levels were strikingly high with normal glucagon and gastrin levels. X-ray of the chest revealed a well-defined mass in the right upper zone with tracheal shift, which was confirmed with computed tomography [CT] of the chest. The mass was resected and the patient became asymptomatic. This case shows that secretory diarrhoea caused by VIP and produced by ganglioneuroblastoma indicates a favourable prognosis, provided it is resectable

Immunodiagnosis of human Wuchereria bancrofti infection using a pair of monoclonal antibodies against worm antigen

This study was designed to prepare monoclonal antibodies [MAbs] against filarial worm antigen [FWA] with immunodiagnostic potential for human filariasis. These MAbs were initially screened and then tested for their specificities against different parasite antigens [S.mansoni SEA, Echinococus granulosus and Fasciola hepatica] by ELISA. From a panel of anti-filarial antigen MAbs; a pair of MAbs [9F/10B and 5F1 611], highly reactive with filarial antigen and showing no cross reactivity against other parasites antigens were selected and characterized. The pair was found to be of IgG1 subclass. Identification of target antigens recognized by MAbs was performed using immunoelectrophoresis, SDS-polyacrylamid gel electrophoresis and enzyme-linked immunoelectrotransfer blot techniques. Both MAbs recognized one band with 88 kDa molecular weight by western blots. Chemical nature of MAbs target antigens was identified by periodate treatment method and proved to be glycoprotein in nature. The pair of MAbs was employed in sandwich ELISA for the defection of circulating filarial antigen [CFA]; one MAb [9F/10B] was used as antigen capturing antibody and the other [5F/6H] as peroxidase-conjugated antigen detecting antibody. The assay reached a lower detection limit of 125 ng/ml of filarial antigen. CFA levels were measured in serum samples from 71 filariasis patients [47 with microfilaraemia and 24 with elephantiasis], 45 patients with other parasites including schistosomiasis, fascioliasis and echinococcosis and 39 healthy individuals as negative control. CFA levels were detected in sera of 68 out of 71 filariasis patients showing an overall sensitivity of 95.8% [91.7% sensitivity for microfilaraemia group and 100% sensitivity for elephantiasis group]. All negative control sera were negative for CFA, while 3 patients out of the other parasite group were positive for CFA giving an overall specificity of 96.4%. These findings suggest that [9F/IOB] MAb and [5F/6H] MAb could be used as a reliable diagnostic indicator for the activity of human filariasis and as a cure monitor particularly in control programs for endemic areas