Automatic resynchronisation of synchronous machines

Imperial Users onl

Cloning and characterisation of heat shock and wound-induced genes in pea (pisum sativum L.)

Plant productivity in many regions of the world is limited primarily as a result of environmental stresses. High temperature and wounding caused by pest and pathogen infection are among the main factors accounting for unpredictable and often severe yield losses worldwide. These stresses, force the plants to alter then gene expression in order to adapt to the changed environment. Attempts were made in the study to isolate and characterise the differentially expressed heat shocked and wound-induced genes to understand the underlying molecular mechanism of heat shock and wounding response. The isolation of the promoters and their use to derive the tissue-specific and high expression of the linked coding sequences will be proved practically more significant. A cDNA clone designated LP 19 was isolated from a differential screening of a cDNA library prepared from lignifying pods of pea line L59. Sequence homology analysis showed that LP19 belongs to the hsp70 gene family. Northern analysis of RNA from pods from pea lines of different genotypes, showing the presence or absence of pod lignification, showed that LP 19 expression was specifically associated with lignification. Several cDNA species derived from transcripts of the LP 19 gene were subsequently isolated, which showed varying positions of poly (A) addition to the 3' untranslated region. Southern blotting of genomic DNA indicated the presence of single gene corresponding to LP 19.The pea hsp70 gene corresponding to LP 19 was isolated from a pea genomic library using LP 19 as a probe. The pea hsp70(LP19) gene predicts an open reading frame encoding a polypeptide of 648 amino acid residues. This sequence is similar to other plant hsp70 proteins. However, unlike most other plant hsp70 genes, the pea hsp70(LP19) gene lacks an intron. 1.8 kb of 5' flanking sequence of hsp70(LP19) gene was also sequenced. The promoter region contains 6 putative consensus heat shock elements (HSEs) as well as 4 A-T rich sites upstream from TATA box. Induction of gene expression of the pea hsp70(LP19) was observed in all organs of the plant after heat shock; the highest level of expression was observed in root, followed by stem and least in leaves. A similar expression pattern for a corresponding gene was observed in chickpea (Cicer arietinum L.). Other stress conditions such as salt stress and wounding failed to induce the expression of hsp70LP(19) gene both in pea and chickpea. The pea hsp70(LP19) promoter region, including 1.8 kb 5'-flanking sequence, and the first 18 amino acids of the coding region, was fused with coding sequence for P- glucuronidase (GUS). Tobacco plants were transformed with this chimaeric gene in order to study tissue specific and developmental expression of the hsp70(LP19) promoter. Histological staining of GUS activity in transgenic tobacco plants showed that protein was present predominantly in the phloem tissue in stem, root and petioles In addition, developmental expression of the hsp70(LP19) gene promoter, without heat shock, was observed in petals, pollen grains, developing seeds as well as in germinating seeds and seedlings at different stages of growth. Quantitative assay of GUS activity by fluorometric assay was used to follow the time course of protein accumulation. Activity was detected within few minutes of the start of heat shock and increased to a maximum after 6 hrs. A high level of GUS activity was observed only in the heat shocked parts of the plant; no endogenous signal that spread systemically from the heat shocked areas to the rest of the plant was observed.Pea and chickpea plants showed a transient increase of polyphenol oxidase (PPO) with maximum level at 48 hrs after wounding. No systemic induction of PPO was observed in unwounded parts in response to both wounding and MeJA treatment. In order to isolate transcripts expressed differentially in response to wounding, a pea subtractive cDNA library was made. 21 subtracted cDNA clones were partially sequenced. Most of the subtracted cDNA clones showed homology with wound or pathogen induced sequences. Northern analysis of the genes corresponding to the subtracted cDNA clones (SC3, SC7, SC12, SC33, SC57 and SC58), indicated differential expression in response to wounding. Full length or nearly full length cDNAs corresponding to 4 subtracted cDNA clones, designated SC10, SC15, SC57 and SC58, were isolated and sequenced. These cDNA clones will be further studied and efforts will be made to isolate their promoters. The tissue-specific expression will be carried out by using promoter-reporter system. These isolated cDNA clones were partially characterised and will be available for further studies to isolate their respective promoters. The tissue specific expression will be carried out by using promoter-reporter system

Primary billiary cirrhosis (antimitochondrial antibody negative) leading to secondary amyloidosis

A 49 years old lady presented with low-grade fever (99-100degreesF) for 2 years. During this time she was extensively worked-up for pyrexia of unknown origin but no diagnosis could be established. Her Initial blood work-up was all negative except high alkaline phosphatase and gamma GT (374 IU and 195 IU respectively). She later presented to our tertiary care centre with facial swelling, flushing and bilateral pedal swelling for 3 months. Along with generalized body swelling she had frothy urine. She was diagnosed as nephrotic syndrome on the basis of nephrotic range proteinuria. Her Renal biopsy done for workup of nephrotic was positive for AA amyloid. Also, her gastrointestinal biopsy was suggestive of amyloidosis. As a workup for secondary amyloidosis, her liver biopsy was done which revealed features of primary billiary cirrhosis (PBC)

Molecular Basis for Pathogenesis of Steatohepatitis: Contemporary Understanding and New Insights

Nonalcoholic fatty liver disease (NAFLD) is characterized by a broad spectrum of clinical and histological presentations, ranging anywhere from simple steatosis to steatohepatitis. Of the patients with NAFLD, only a small fraction goes on to develop inflammation and fibrosis (i.e. NASH). Hence, understanding the underlying molecular mechanisms, which play part in progression of NAFLD and determine the disease severity, is extremely important. Almost two decades ago, Day and colleagues first described the “two-hit hypothesis” to explain progression of NAFLD. However, since then, the advances in field of molecular research have identified that NAFLD development and progression involves complex interplay of numerous determinants, including gut-derived signals, endoplasmic reticulum stress, adipose-derived adipokines, nutritional factors, hormonal imbalances and components of innate immunity which act in concert on genetically predisposed individuals to induce liver inflammation. This chapter reviews the different players of this “multiple-hit model”

Next big threat for Pakistan Hepatocellular Carcinoma (HCC)

In our country, world hepatitis day (28th May 2013) was observed as a liver cancer day to draw global attention on the global health menace caused by Hepatocellular carcinoma (HCC). This is the right time to write a review article to apprise the nation of this growing burden of HCC caused most commonly by viruses in our country. Pakistan is also recognized as one of the countries of the world where hepatitis C virus (HCV) is endemic. Recent large national surveys suggest an overall HCV prevalence of 4.8% and that of HBV as 2.5%. There are however communities where the sero-prevalence of HCV can be as high as 23%. No wonder that chronic liver disease is the fifth most common reason for morbidity and mortality in the country and Pakistan has been perhaps accurately called a cirrhotic state . Hence majority of such patients are at risk of developing HCC

Hereditary hemochromatosis.

Objective: To describe the clinical and laboratory features of hereditary hemochromatosis associated liver disease in a tertiary care hospital. Study Design: Observational study. Place and Duration of Study: The Aga Khan University Hospital, Karachi, from January 2002 to October 2012. Methodology: Charts of patients with Hereditary Hemochromatosis (HHC) were reviewed. Data collected and analyzedconsisting of clinical presentations, liver function tests, serum ferritin, transferrin saturation, hepatic imaging and histologyin patients with HHC. Results: A total of 22 patients were identified as having hemochromatosis. All subjects were men with a mean age of 53 ± 9.2 years at the time of diagnosis. The most common presentation was skin pigmentation seen in 17 (77%), followed by loss of libido/ impotence in 11 (50%) and then arthralgias in 10 (45%) and weakness in 6 (27%). Eleven (50%) subjects had diabetes mellitus and one subject had concomitant cardiac involvement. Patients with diabetes were diagnosed earlier as compared to those without it. Eighteen (81%) subjects had cirrhosis at the time of diagnosis. Serum iron was 164 ± 53 ug/dl, ferritin 3391 ± 1960 ug/L, TIBC 202 ± 61 ug/dl and transferrin saturation 76.8 ± 14%. Liver biopsy was done in 10(45%) and using Pearls\u27 stain histopathological features were consistent with hemochromatosis and none had carcinoma.Only 3 (14%) patients had regular phlebotomy. Conclusion: Hemochromatosis is not a rare disease in Pakistan and should be looked in those subjects whose liver function tests are deranged

Are we ready for a new epidemic of under recognized liver disease in South Asia especially in Pakistan? Non alcoholic fatty liver disease

Nonalcoholic fatty liver disease (NAFLD) is increasingly recognized as an important public health problem nowadays. NAFLD encompass a variety of liver pathologies including simple steatosis, NASH, fibrosis, cirrhosis and finally cancer. It is associated with obesity, metabolic syndrome, dyslipidaemia, Insulin resistance (IR) and type 2 diabetes. It is the most common chronic liver disease in USA and considered to be increasing in Asia Pacific region including South Asia however there is no community based study from Pakistan. Customarily NAFLD had been regarded as a benign disease; however clinical as well as epidemiological studies had contradicted this belief because approximately 20% of the patients with NAFLD had NASH which has propensity to develop cirrhosis and ultimately to HCC. The diagnosis of NAFLD is made most of the times incidentally on abdominal imaging which is done for other purposes. Despite its prevalence, treatment options are very limited. However modification of risk factors such as dyslipidemia, diabetes control and weight reduction does help in NAFLD. Fatty liver results due to lack of physical activity; hence foremost step to manage such patients would be to develop the healthy life style. We need population based studies in our country so that we can protect our population from a new epidemic

Diagnosis of Dengue Infection Using Conventional and Biosensor Based Techniques

Dengue is an arthropod-borne viral disease caused by four antigenically different serotypes of dengue virus. This disease is considered as a major public health concern around the world. Currently, there is no licensed vaccine or antiviral drug available for the prevention and treatment of dengue disease. Moreover, clinical features of dengue are indistinguishable from other infectious diseases such as malaria, chikungunya, rickettsia and leptospira. Therefore, prompt and accurate laboratory diagnostic test is urgently required for disease confirmation and patient triage. The traditional diagnostic techniques for the dengue virus are viral detection in cell culture, serological testing, and RNA amplification using reverse transcriptase PCR. This paper discusses the conventional laboratory methods used for the diagnosis of dengue during the acute and convalescent phase and highlights the advantages and limitations of these routine laboratory tests. Subsequently, the biosensor based assays developed using various transducers for the detection of dengue are also reviewed