Insights into Membrane Curvature Sensing and Membrane Remodeling by Intrinsically Disordered Proteins and Protein Regions.

Cellular membranes are highly dynamic in shape. They can rapidly and precisely regulate their shape to perform various cellular functions. The protein's ability to sense membrane curvature is essential in various biological events such as cell signaling and membrane trafficking. As they are bound, these curvature-sensing proteins may also change the local membrane shape by one or more curvature driving mechanisms. Established curvature-sensing/driving mechanisms rely on proteins with specific structural features such as amphipathic helices and intrinsically curved shapes. However, the recent discovery and characterization of many proteins have shattered the protein structure-function paradigm, believing that the protein functions require a unique structural feature. Typically, such structure-independent functions are carried either entirely by intrinsically disordered proteins or hybrid proteins containing disordered regions and structured domains. It is becoming more apparent that disordered proteins and regions can be potent sensors/inducers of membrane curvatures. In this article, we outline the basic features of disordered proteins and regions, the motifs in such proteins that encode the function, membrane remodeling by disordered proteins and regions, and assays that may be employed to investigate curvature sensing and generation by ordered/disordered proteins.

HEALTH AND PERFORMANCE OF MILITARY PERSONNEL IN COLD CLIMATIC ENVIRONMENT OF THE WESTERN HIMALAYAS.

Indian Armed Forces are constrained to deploy a large number of troops in the western Himalayas in the interest of national security and territorial integrity. The region represents extremely rugged, arid and cold climatic conditions. The altitude ranges from 8000 to 23000 feet with winter temperatures ranging from -35°C to - 55°C in some regions. Low environmental humidity, hypo-baric hypoxia and high solar ultra-violet radiation with its attendant problems further compound the hardships faced by the troops in these climatic conditions. The role of the Armed Forces medical personnel is extremely challenging, as they have to ensure maintenance of health and physical fitness of the troops to ensure optimal performance during peace and during operations. These considerations include nutrition, physical fitness programmes suitable for the terrain and climatic conditions, protection against cold and hypoxia induced health problems, clothing and shelter taking into consideration the ergonomic factors, human waste disposal and prompt medical attention and evacuation in case of illness. An overview of the effects of cold hypoxic environment on health and performance of Indian troops, measures employed by the Armed Forces to maintain health of troops including psychological factors and the incidence of various cold induced health problems during peace time compared to operational period over the last 10 years is presented in this paper.

ELECTRON MICROSCOPY IN LUPUS NEPHRITIS (A Case Report).

A female patient aged 8 years presented with mild proteinuria and microscopical haematuria, The serological markers and histological findings in renal needle biopsy were inconclusive. Ultrastructural study revealed features of lupus nephritis. Case is presented to elucidate value of electron microscopy in such cases.

MICROWAVE STIMULATED FIXATION AND RAPID PROCESSING OF TISSUE FOR HISTOPATHOLOGY.

A rapid method for obtaining high quality paraffin sections is described. This method enables preparation of paraffin blocks in about 20 minutes and is based on microwave stimulated tissue fixation and processing. A total of 200 tissues were processed. Tissue blocks of size 1×1×0.5 were found ideal for processing. Three protocols were evaluated for tissue processing using different timings of exposure to graded alcohols, chloroform and wax. It was observed that utilizing an additional step of exposure to 70 per cent alcohol during tissue dehydration resulted in preparation of paraffin blocks which were light microscopically excellent and highly comparable to conventional methods.

HYPOFIBRINOGENEMIA (A Report of Two Cases).

Hypofibrinogenemia is an uncommon bleeding disorder. Two siblings with mild bleeding diathesis were investigated and diagnosed as suffering from this disorder. The cases are discussed keeping in view of their rarity.

HORMONAL MARKERS IN THE STUDY OF PITUITARY ADENOMAS.

Twenty pituitary adenomas were studied using light microscopy, immunohistochemistry and electron microscopy. Based on clinical manifestations of hormonal hypersecretion they were divided into two groups, i.e. group-I (12 patients) with no endocrine dysfunction and group-II (8 patients) with endocrine dysfunction. Group-I could be further sub-divided into two groups based on IHC : group LA in which no hormone could be localised in the tissue (null cell adenomas) and group IB where hormones could be localised in the tissue (1). Tumours in group II, with light microscopy, were acidophil (n=5), basophil (n=1) or mixed (n=2) adenomas. Eight of these 20 cases were plurihormonal. Growth hormone, and prolactin were the commonest combination. This study has helped in the reclassification of the pituitary adenomas according to the hormone they produce.

IMMUNOPHENOTYPING OF ACUTE LEUKAEMIAS : A CRITICAL ANALYSIS OF 35 CASES.

Accurate classification of acute leukaemias is essential for proper case management. The utility of monoclonal antibodies in the diagnosis and classification of acute leukaemias is well established. This diagnostic utility relates primarily to two points : firstly the distinction between acute myeloid leukaemia and acute lymphoblastic leukaemia and secondly to subtypes of acute lymphoblastic leukaemia. Leukaemic cells were immunophenotyped using the alkaline phosphatase antialkaline phosphatase techniques. The monoclonal antibodies were very useful in distinguishing cases of acute myeloid leukaemia from acute lymphoblastic leukaemia. Cases of acute lymphoblastic leukaemia with CD10 positivity showed a better prognosis. T-cell acute lymphoblastic leukaemia was uncommon and was associated with unfavourable prognosis. The alkaline phosphatase antialkaline phosphatase technique served as a reliable and convenient method for immunophenotyping of leukaemias.

High frequency embryoid and plantlet formation from tissue cultures of the Finger millet-Eleusine coracana (L.) Gaertn.

Compact nodulated embryogenic callus differentiated from cultured seeds of Eleusine coracana (Finger Millet) on Murashige and Skoog (1962) basal medium with 2,4-dichlorophenoxyacetic acid (1.0, 3.0 mg (l)). This embryogenic callus was maintained on a medium with a lower level of 2,4 - dichlorophenoxyacetic acid. At every subculture the embryogenic callus had some preexisting embryoids in it. With this method of subculture the callus has retained its morphogenic potential for four years. Following transfer to media with different levels of auxins and cytokinins, the callus showed varied patterns of growth and morphogenesis. Embryoids could be germinated in profusion to form plantlets which could be transferred to the field. Shoot buds also differentiated from the whole surface of the embryoid or from the flattened meristemoids.