Etiological spectrum of hypokalemic paralysis: A retrospective analysis of 29 patients

Background:

Hypokalemic paralysis is characterized by episodes of acute muscle weakness associated with hypokalemia. In this study, we evaluated the possible etiological factors in patients of hypokalemic paralysis.

Materials and Methods:

We reviewed the records of 29 patients who were admitted with a diagnosis of hypokalemic paralysis. Modified Guillain-Barre´ Syndrome disability scale was used to grade the disability.

Results:

In this study, 15 (51.7%) patients had secondary causes of hypokalemic paralysis and 14 patients (42.3%) had idiopathic hypokalemic paralysis. Thyrotoxicosis was present in six patients (20.6%), dengue infection in four patients (13.7%), distal renal tubular acidosis in three patients (10.3%), Gitelman syndrome in one patient (3.4%), and Conn''s syndrome in one patient (3.4%). Preceding history of fever and rapid recovery was seen in dengue infection-induced hypokalemic paralysis. Approximately 62% patients had elevated serum creatinine phosphokinase. All patients had recovered completely following potassium supplementation. Patients with secondary causes were older in age, had significantly more disability, lower serum potassium levels, and took longer time to recover.

Conclusion:

In conclusion, more than half of patients had secondary causes responsible for hypokalemic paralysis. Dengue virus infection was the second leading cause of hypokalemic paralysis, after thyrotoxicosis. Presence of severe disability, severe hypokalemia, and a late disease onset suggested secondary hypokalemic paralysis.     

In vivo contribution of nestin‐ and GLAST‐lineage cells to adult hippocampal neurogenesis

Radial glia‐like cells (RGCs) are the hypothesized source of adult hippocampal neurogenesis. However, the current model of hippocampal neurogenesis does not fully incorporate the in vivo heterogeneity of RGCs. In order to better understand the contribution of different RGC subtypes to adult hippocampal neurogenesis, we employed widely used transgenic lines (Nestin‐CreER^T2 and GLAST::CreER^T2 mice) to explore how RGCs contribute to neurogenesis under basal conditions and after stimulation and depletion of neural progenitor cells. We first used these inducible fate‐tracking transgenic lines to define the similarities and differences in the contribution of nestin‐ and GLAST‐lineage cells to basal long‐term hippocampal neurogenesis. We then explored the ability of nestin‐ and GLAST‐lineage RGCs to contribute to neurogenesis after experimental manipulations that either ablate neurogenesis (i.c.v. application of the anti‐mitotic AraC, cytosine‐β‐D‐arabinofuranoside) or stimulate neurogenesis (wheel running). Interestingly, in both ablation and stimulation experiments, labeled RGCs in GLAST::CreER^T2 mice appear to contribute to neurogenesis, whereas RGCs in Nestin‐CreER^T2 mice do not. Finally, using NestinGFP reporter mice, we expanded on previous research by showing that not all RGCs in the adult dentate gyrus subgranular zone express nestin, and therefore RGCs are antigenically heterogeneous. These findings are important for the field, as they allow appropriately conservative interpretation of existing and future data that emerge from these inducible transgenic lines. These findings also raise important questions about the differences between transgenic driver lines, the heterogeneity of RGCs, and the potential differences in progenitor cell behavior between transgenic lines. As these findings highlight the possible differences in the contribution of cells to long‐term neurogenesis in vivo, they indicate that the current models of hippocampal neurogenesis should be modified to include RGC lineage heterogeneity. © 2013 Wiley Periodicals, Inc.     

Effective use of simple computer programmes and clay models to demonstrate the planning and operative steps for teaching and presentations

Background:Presenting and demonstrating a surgical procedure in the current era is difficult without good intraoperative pictures and videos. A long, complex, multi-staged surgery is better illustrated by detailed intraoperative images at various stages. Although desirable, it may be difficult due to various reasons.Results:It is a simple technique with a moderate learning curve. Once familiar with technique, one can effectively use the technique to convey the details in much more clear manner.Conclusion:It is a simple and effective way of communicating through digital images, and gives the audience a 3 dimensional idea about the concept.KEY WORDS: Clay models in plasticine surgery, photography, presentations in plastic surgery, teaching and patient education, use of clay models for presentations     

Falcipain-1, a Plasmodium falciparum cysteine protease with vaccine potential

Cysteine proteases (falcipains) of Plasmodium falciparum are potential targets for antimalarial chemotherapy, since they have been shown to be involved in important cellular functions such as hemoglobin degradation and invasion/rupture of red blood cells during parasite life cycle. The role of falcipain-1 at the asexual blood stages of the parasite still remains uncertain. This is mainly due to a lack of methods to prepare this protein in an active form. In order to obtain biologically active falcipain-1, a number of falcipain-1 constructs were designed and a systematic assessment of the refolding conditions was done. We describe here the expression, purification, and characterization of a falcipain-1 construct encoding mature falcipain-1 and 35 amino acids from the C-terminal of the pro domain. Recombinant falcipain-1 was overexpressed in the form of inclusion bodies, solubilized, and purified by Ni²⁺-nitrilotriacetic acid affinity chromatography under denaturing conditions. A systemic approach was then followed to optimize refolding parameters. An optimum refolding condition was obtained, and the yield of the purified refolded falcipain-1 was ~1 mg/liter. Activity of the protein was analyzed by fluorometric and gelatin degradation assays. Immunolocalization studies using anti-falcipain-1 sera revealed a distinct staining at the apical end of the P. falciparum merozoites. Previous studies using falcipain-1-specific inhibitors have suggested a role of falcipain-1 in merozoite invasion. Based on its localization and its role in invasion, we analyzed the immunogenicity of falcipain-1 in mice, followed by heterologous challenge with Plasmodium yoelii sporozoites. Our results suggest a possible role of falcipain-1 in merozoite invasion.     

Comparison of smear cytology with histopathology of the CT guided stereotactic brain biopsy

The study was undertaken to determine the accuracy of cytological diagnosis of CNS lesions by comparing it with the final histopathological diagnosis of CT guided stereotactic brain biopsy. Squash preparations were prepared from 25 cases of CNS lesions operated in two years. These included 18 astrocytomas, 1 metastatic deposits, 1 epidermoid cyst, 1 Toxoplasmosis, 1 granulomatous inflammation and 3 cases showing normal brain parenchyma. The cytological diagnosis was available to the neurosurgeon within 10 minutes. The cytohistological correlation with paraffin block sections worked out to be 92%. Thus, this proved to be a fairly reliable and rapid method for immediate intra-operative diagnosis.     

Sound localization during homotopic and heterotopic bilateral cooling deactivation of primary and nonprimary auditory cortical areas in the cat

Although the contributions of primary auditory cortex (AI) to sound localization have been extensively studied in a large number of mammals, little is known of the contributions of nonprimary auditory cortex to sound localization. Therefore the purpose of this study was to examine the contributions of both primary and all the recognized regions of acoustically responsive nonprimary auditory cortex to sound localization during both bilateral and unilateral reversible deactivation. The cats learned to make an orienting response (head movement and approach) to a 100-ms broad-band noise stimulus emitted from a central speaker or one of 12 peripheral sites (located in front of the animal, from left 90 degrees to right 90 degrees , at 15 degrees intervals) along the horizontal plane after attending to a central visual stimulus. Twenty-one cats had one or two bilateral pairs of cryoloops chronically implanted over one of ten regions of auditory cortex. We examined AI [which included the dorsal zone (DZ)], the three other tonotopic fields [anterior auditory field (AAF), posterior auditory field (PAF), ventral posterior auditory field (VPAF)], as well as six nontonotopic regions that included second auditory cortex (AII), the anterior ectosylvian sulcus (AES), the insular (IN) region, the temporal (T) region [which included the ventral auditory field (VAF)], the dorsal posterior ectosylvian (dPE) gyrus [which included the intermediate posterior ectosylvian (iPE) gyrus], and the ventral posterior ectosylvian (vPE) gyrus. In accord with earlier studies, unilateral deactivation of AI/DZ caused sound localization deficits in the contralateral field. Bilateral deactivation of AI/DZ resulted in bilateral sound localization deficits throughout the 180 degrees field examined. Of the three other tonotopically organized fields, only deactivation of PAF resulted in sound localization deficits. These deficits were virtually identical to the unilateral and bilateral deactivation results obtained during AI/DZ deactivation. Of the six nontonotopic regions examined, only deactivation of AES resulted in sound localization deficits in the contralateral hemifield during unilateral deactivation. Although bilateral deactivation of AI/DZ, PAF, or AES resulted in profound sound localization deficits throughout the entire field, the cats were generally able to orient toward the hemifield that contained the acoustic stimulus, but not accurately identify the location of the stimulus. Neither unilateral nor bilateral deactivation of areas AAF, VPAF, AII, IN, T, dPE, nor vPE had any effect on the sound localization task. Finally, bilateral heterotopic deactivations of AI/DZ, PAF, or AES yielded deficits that were as profound as bilateral homotopic cooling of any of these sites. The fact that deactivation of any one region (AI/DZ, PAF, or AES) was sufficient to produce a deficit indicated that normal function of all three regions was necessary for normal sound localization. Neither unilateral nor bilateral deactivation of AI/DZ, PAF, or AES affected the accurate localization of a visual target. The results suggest that hemispheric deactivations contribute independently to sound localization deficits.