Role of Double Inversion Recovery Sequence in Neuro-imaging on 3 Tesla MRI.

Double Inversion Recovery (DIR) is a robust sequence designed to suppress fat and water signals using two 180° inversion pulses to produce prominent gray matter contrast with high spatial resolution. It has proven to be more sensitive in delineating white matter signal abnormalities than conventional MR techniques. In our study, the highest image contrast with lesion load was observed using DIR over FLAIR and T2 weighted imaging. DIR is evidently valuable for the detection of demyelinating lesions observed in multiple sclerosis (MS), malignancies, epileptogenic foci, and cortical anomalies. Hence this pictorial review is intended to assess the diagnostic efficacy of DIR modality in clinical Neuro-imaging.

Brunneroma: A Rare Cause of Duodeno-duodenal Intussusception.

Brunner gland hamartoma (brunneroma) is a rare benign tumor of the duodenum. It is usually asymptomatic and detected incidentally by endoscopy or other imaging modality. The definitive diagnosis is based on histopathological findings. These may mimic tumors of other natures, such as gastrointestinal stromal tumors (GIST), carcinoids, lipomas, and leiomyomas. Here, we present a case of duodenal polyp presenting with abdominal pain and obstructive symptoms that caused duodenal intussusception. It was surgically removed and found to be a brunneroma on histopathology. HOW TO CITE THIS ARTICLE: Patankar AM, Wadhwa AM, Bajaj A, Ingule A, Wagle P. Brunneroma: A Rare Cause of Duodeno-duodenal Intussusception. Euroasian J Hepato-Gastroenterol 2016;6(1):84-88.

Differential elicitation of two processing proteases controls the processing pattern of the trypsin proteinase inhibitor precursor in Nicotiana attenuata.

Trypsin proteinase inhibitors (TPIs) of Nicotiana attenuata are major antiherbivore defenses that increase dramatically in leaves after attack or methyl jasmonate (MeJA) elicitation. To understand the elicitation process, we characterized the proteolytic fragmentation and release of TPIs from a multidomain precursor by proteases in MeJA-elicited and unelicited plants. A set of approximately 6-kD TPI peptides was purified from leaves, and their posttranslational modifications were characterized. In MeJA-elicited plants, the diversity of TPI structures was greater than the precursor gene predicted. This elicited structural heterogeneity resulted from differential fragmentation of the linker peptide (LP) that separates the seven-domain TPI functional domains. Using an in vitro fluorescence resonance energy transfer assay and synthetic substrates derived from the LP sequence, we characterized proteases involved in both the processing of the TPI precursor and its vacuolar targeting sequence. Although both a vacuolar processing enzyme and a subtilisin-like protease were found to participate in a two-step processing of LP, only the activity of the subtilisin-like protease was significantly increased by MeJA elicitation. We propose that MeJA elicitation increases TPI precursor production and saturates the proteolytic machinery, changing the processing pattern of TPIs. To test this hypothesis, we elicited a TPI-deficient N. attenuata genotype that had been transformed with a functional NaTPI gene under control of a constitutive promoter and characterized the resulting TPIs. We found no alterations in the processing pattern predicted from the sequence: a result consistent with the saturation hypothesis.

Manipulation of endogenous trypsin proteinase inhibitor production in Nicotiana attenuata demonstrates their function as antiherbivore defenses.

Evidence for the in planta defensive function of trypsin protease inhibitors (TPIs) comes from observations of enhanced herbivore resistance after heterologous TPI expression or the manipulation of signal cascades that activate numerous defense responses, including TPI production; no studies have altered the expression of an endogenous pi gene to examine defensive function. We isolated two genes with seven- and six-repeat TPI domains from Nicotiana attenuata from the potato (Solanum tuberosum) PI-II family. To determine whether endogenous TPIs in N. attenuata function defensively against the native herbivores, hornworm (Manduca sexta) and mirids (Tupiocoris notatus), we expressed 175 bp of the seven-domain pi from N. attenuata in an antisense orientation in a TPI-producing genotype to reduce TPI expression and expressed the full-length seven-domain pi in a sense orientation under control of a constitutive promoter to restore TPI activity in a natural genotype from Arizona unable to produce TPIs. Constitutive and inducible TPI production in two antisense lines were diminished by 80% to 90% and 33% to 52%, respectively, and sense expression restored 67% of the activity found in the TPI-producing genotype after caterpillar attack in the TPI-deficient A genotype. Hornworm larvae fed on genotypes with low or no TPI activity grew faster, had higher survivorship, and produced heavier pupae than those that fed on genotypes with high TPI activity. T. notatus showed higher preference for genotypes with low or no TPI activity than for genotypes with high TPI levels. We conclude that endogenous TPIs are an effective defense against these native herbivores.

Constitutive and inducible trypsin proteinase inhibitor production incurs large fitness costs in Nicotiana attenuata.

Plant trypsin proteinase inhibitors (TPIs) are potent herbivore- and jasmonate (JA)-induced defenses, but support for the commonly invoked explanation for their inducible expression, namely their associated fitness costs, has been elusive. To determine whether the expression of TPIs incurs fitness costs, we expressed 175 bp of the seven-domain pi from Nicotiana attenuata in an antisense orientation in a TPI-producing genotype (WT) of N. attenuata to reduce TPI expression. Moreover, we expressed the full-length seven-domain pi in a sense orientation under control of a constitutive promoter to restore TPI activity in a natural genotype unable to produce TPIs because of a mutation in its endogenous pi gene. Lifetime reproductive output was determined from high and low TPI-producing plants of the same genetic background with and without JA elicitation and grown in the same pot to simulate natural competitive and nutrient regimes. Transformants with either low or no TPI activity grew faster and taller, flowered earlier, and produced more seed capsules (25-53%) than did neighboring TPI-producing genotypes, and JA elicitation increased TPI production and decreased seed capsule production further. Growth under high light levels only marginally reduced these fitness costs. Results were similar regardless of whether TPI activity was suppressed or restored by transformation: the larger the difference in TPI activity between neighbors, the larger the difference in seed capsule production (R(2) = 0.57). TPI production is costly for a plant's components of fitness when grown under realistic competitive regimes and is consistent with the hypothesis that inducibility evolved as a cost-saving mechanism.

Bitter gourd proteinase inhibitors: potential growth inhibitors of Helicoverpa armigera and Spodoptera litura.

Proteinase inhibitors (PIs) from the seeds of bitter gourd (Momordica charantia L.) were identified as strong inhibitors of Helicoverpa armigera gut proteinases (HGP). Biochemical investigations showed that bitter gourd PIs (BGPIs) inhibited more than 80% HGP activity. Electrophoretic analysis revealed the presence of two major proteins (BGPI-1 and-2) and two minor proteins (BGPI-3 and-4) having inhibitory activity against both trypsin and HGP. The major isoforms BGPI-1 and BGPI-2 have molecular mass of 3.5 and 3.0 kDa, respectively. BGPIs inhibited HGP activity of larvae fed on different host plants, on artificial diet with or without added PIs and proteinases excreted in fecal matter. Degradation of BGPI-1 by HGP showed direct correlation with accumulation of BGPI-2-like peptide, which remained stable and active against high concentrations of HGP up to 3 h. Chemical inhibitors of serine proteinases offered partial protection to BGPI-1 from degradation by HGP, suggesting that trypsin and chymotrypsin like proteinases are involved in degradation of BGPI-1. In larval feeding studies, BGPIs were found to retard growth and development of two lepidopteran pests namely Helicoverpa armigera and Spodoptera litura. This is the first report showing that BGPIs mediated inhibition of insect gut proteinases directly affects fertility and fecundity of both H. armigera and S. litura. The results advocate use of BGPIs to introduce insect resistance in otherwise susceptible plants.