Cerebrovascular Manifestations of Neurosarcoidosis: An Underrecognized Aspect of the Imaging Spectrum

Involvement of the central nervous system by sarcoidosis, also referred to as neurosarcoidosis, is seen clinically in about 5% of patients with systemic disease. CNS involvement most frequently affects the leptomeninges and cranial nerves, though the ventricular system, brain parenchyma, and pachymeninges may also be involved. Even though the involvement of the intracranial vascular structures is well-known on postmortem studies, there is scant literature on imaging manifestations secondary to the vessel wall involvement, being confined mostly to isolated case reports and small series. The authors present a review of various cerebrovascular manifestations of neurosarcoidosis, along with a brief synopsis of the existing literature.

Blunt Cerebrovascular Injuries: Advances in Screening, Imaging, and Management Trends

Blunt cerebrovascular injury is a relatively uncommon but sometimes life-threatening injury, particularly in patients presenting with ischemic symptoms in that vascular territory. The decision to pursue vascular imaging (generally CT angiography) is based on clinical and imaging findings. Several grading scales or screening criteria have been developed to guide the decision to pursue vascular imaging, as well as to recommend different treatment options for various injuries. The data supporting many of these guidelines and options are limited however. The purpose of this article is to review and compare these scales and criteria and the data supporting clinical efficacy and to make recommendations for future research in this area.

Short EpiData course: do participants use the data entry tool two years post-training?

SETTING

Training courses on data entry are few and far between compared to analysis. To address this gap, we conducted a short 2-day course on quality-assured data capture using EpiData for public health professionals in Bangalore and Puducherry, India, in 2013.

OBJECTIVE

To determine the proportion of participants who used EpiData and taught the software to others during the 2-years after training and explore the reasons for doing/not doing so.

DESIGN

Cross-sectional study with self-administered, semi-structured questionnaire developed using web-based Google Forms. We performed a manual thematic analysis to identify the major reasons for using/not using EpiData.

RESULTS

Of 46 participants, 38 (83%) responded. Of 31 participants involved in research, 17 (55%) had used EpiData, of whom 6 (35%) had performed double entry and validation. Of the 14 who did not use EpiData, 11 had used MS Excel or SPSS/Epi Info for data entry. Of the 38 respondents, 29 (76%) had taught EpiData to other colleagues and students. Reasons for using EpiData included its user-friendliness, its being open access and the ease in preventing data entry errors. Reasons for not performing double entry included lack of time and manpower.

CONCLUSION

The short course on EpiData was effective in knowledge transfer and provides a scalable model for incorporation into the teaching curricula of medical schools and research institutions.

Is energy drink safe? A cross sectional study on the effects of energy drink on medical students from a medical school of Nepal

Background: Energy drinks that contain caffeine, taurine, vitamins, herbal supplements, sugar or sweeteners are marketed to improve energy, weight loss, stamina, athletic performance and concentration. Recently some of energy drink has been banned in different countries like Saudi Arabia. In Nepal none of the studies has been done to report the effect of energy drink on health. The main objective of the study was to find out the effect of energy drink on health of medical students. Materials and Methods:  It was a cross sectional questionnaire based study done at Manipal College of Medical Sciences, Pokhara, Nepal on November 2013. Results: Out of 206 students 202 completed the questionnaire completely and their responses were evaluated which gives an overall response rate of 98.05%%. Out of 202 students, 88 (43.56%) students were found consuming energy drinks. The research finding revealed that most of the students who consumed energy drink were male 58%. Most of the students felt energetic after consuming energy drink. The majority of the students were from the second year 79.5%. The majority of the students, 71.6% consumed < 5 cans/week. Among the CNS manifestations students felt energetic, insomnia, euphoria, anxiety, dizziness, hallucination, headache and seizure disorder. Most of the students suffered from palpitation among the CVS manifestations. Other GIT and CVS Manifestations were discomfort, nausea, vomiting, diarrhoea, abdominal pain, constipation, weight loss and chest pain. ANS and miscellaneous manifestations were also seen among the students among which increased stamina , micturation, dry mouth, sweating, burning sensation in the throat, allergic reactions, breathlessness were noted by the students. Headache and insomnia was found more prevalent in males [OR 1.836 95% (CI 0.458, 7.367)] and [OR 1.214, 95 %(CI 0.517, 2.852)], respectively as compared to female students. However, in the case of GIT manifestations viz. abdominal pain and constipation revealed that it was more prevalent among male students [OR 2.292, 95 %(CI( 0.343, 13.638)] and [OR 1.836, 95 %(CI 0.458, 7.367)]. Conclusion:  It is concluded that energy drink gives energy and increases the stamina but it produces neurologic, psychiatric, cardiovascular and gastrointestinal complications on health. Further studies are required on the same field to find out its effect on health in Nepalese population. 

Effect of plasmon-enhancement on photophysics in upconverting nanoparticles

Surface plasmon polaritons (SPP) waves have been shown to significantly affect the near-field photophysical phenomenon. In particular, strong Coulombic interactions can enhance nearby non-linear optics and energy transfer process, while SPP waves also affect other photophysical processes like quenching observed in fluorescent and excitonic systems. Here, using different plasmonic substrates, we show the effect of plasmon-enhancement on quenching, phonon-assisted non-radiative decay, weak Purcell effect or electromagnetic field enhancement, and energy transfer rates of upconverting doped-lanthanide nanoparticles. While the resonant plasmons enhance the local electromagnetic field and the rate of energy transfer leading to enhanced upconversion photoluminescence of infrared radiation to visible light, it can also increase the quenching and non-radiative decay rates of photoexcited electron-hole pairs leading to losses and lower efficiency. These results can guide the design of optimized substrate geometry for using surface plasmons to modulate the photophysics in other applications too.

Eosinophilic ascites. A rare presentation of eosinophilic gastroenteritis

EGED is a rare entity; it should be kept in mind in patient of unexplained abdominal symptoms. Any age group and any part of GI tract can be involved. Eosinophillia may be absent in the peripheral smear and biopsy may be negative in up to 10% of the cases. Here we are reporting a 40 years old male who presented to us with eosinophilic ascites, a rare presentation of serosal variant of eosinophilic gastroenteritis (EGED).

AXR2 encodes a member of the Aux/IAA protein family

The dominant gain-of-function axr2-1 mutation of Arabidopsis causes agravitropic root and shoot growth, a short hypocotyl and stem, and auxin-resistant root growth. We have cloned the AXR2 gene using a map-based approach, and find that it is the same as IAA7, a member of the IAA (indole-3-acetic acid) family of auxin-inducible genes. The axr2-1 mutation changes a single amino acid in conserved domain II of AXR2/IAA7. We isolated loss-of-function mutations in AXR2/IAA7 as intragenic suppressors of axr2-1 or in a screen for insertion mutations in IAA genes. A null mutant has a slightly longer hypocotyl than wild-type plants, indicating that AXR2/IAA7 controls development in light-grown seedlings, perhaps in concert with other gene products. Dark-grown axr2-1 mutant plants have short hypocotyls and make leaves, suggesting that activation of AXR2/IAA7 is sufficient to induce morphological responses normally elicited by light. Previously described semidominant mutations in two other Arabidopsis IAA genes cause some of the same phenotypes as axr2-1, but also cause distinct phenotypes. These results illustrate functional differences among members of the Arabidopsis IAA gene family.

Independent action of ELF3 and phyB to control hypocotyl elongation and flowering time

Light regulates various aspects of plant growth, and the photoreceptor phytochrome B (phyB) mediates many responses to red light. In a screen for Arabidopsis mutants with phenotypes similar to those of phyB mutants, we isolated two new elf3 mutants. One has weaker morphological phenotypes than previously identified elf3 alleles, but still abolishes circadian rhythms under continuous light. Like phyB mutants, elf3 mutants have elongated hypocotyls and petioles, flower early, and have defects in the red light response. However, we found that elf3 mutations have an additive interaction with a phyB null mutation, with phyA or hy4 null mutations, or with a PHYB overexpression construct, and that an elf3 mutation does not prevent nuclear localization of phyB. These results suggest that either there is substantial redundancy in phyB and elf3 function, or the two genes regulate distinct signaling pathways.

Isolation and characterization of a cDNA clone from Arabidopsis thaliana with partial sequence similarity to integrins

An Arabidopsis thaliana cDNA, called At14a, was isolated by immunoscreening an expression library with an anti-integrin antibody. The At14a cDNA is 1459 nucleotides and has an open reading frame encoding a protein of 385 amino acids and a predicted molecular weight of 43kDa. At14a has a small domain that has sequence similarities to integrins from fungi, insects and humans. Transcripts of At14a are found in all Arabidopsis tissues examined, and when expressed as an epitope tagged fusion protein in transgenic plants, At14a localizes partly to the plasma membrane.

From seed germination to flowering, light controls plant development via the pigment phytochrome

Plant growth and development are regulated by interactions between the environment and endogenous developmental programs. Of the various environmental factors controlling plant development, light plays an especially important role, in photosynthesis, in seasonal and diurnal time sensing, and as a cue for altering developmental pattern. Recently, several laboratories have devised a variety of genetic screens using Arabidopsis thaliana to dissect the signal transduction pathways of the various photoreceptor systems. Genetic analysis demonstrates that light responses are not simply endpoints of linear signal transduction pathways but are the result of the integration of information from a variety of photoreceptors through a complex network of interacting signaling components. These signaling components include the red/far-red light receptors, phytochromes, at least one blue light receptor, and negative regulatory genes (DET, COP, and FUS) that act downstream from the photoreceptors in the nucleus. In addition, a steroid hormone, brassinolide, also plays a role in light-regulated development and gene expression in Arabidopsis. These molecular and genetic data are allowing us to construct models of the mechanisms by which light controls development and gene expression in Arabidopsis. In the future, this knowledge can be used as a framework for understanding how all land plants respond to changes in their environment.

A role for brassinosteroids in light-dependent development of Arabidopsis

Although steroid hormones are important for animal development, the physiological role of plant steroids is unknown. The Arabidopsis DET2 gene encodes a protein that shares significant sequence identity with mammalian steroid 5 alpha-reductases. A mutation of glutamate 204, which is absolutely required for the activity of human steroid reductase, abolishes the in vivo activity of DET2 and leads to defects in light-regulated development that can be ameliorated by application of a plant steroid, brassinolide. Thus, DET2 may encode a reductase in the brassinolide biosynthetic pathway, and brassinosteroids may constitute a distinct class of phytohormones with an important role in light-regulated development of higher plants.

Signal-transduction pathways controlling light-regulated development in Arabidopsis

All metazoan cells are able to make decisions about cell division or cellular differentiation based, in part, on environmental cues. Accordingly, cells express receptor systems that allow them to detect the presence of hormones, growth factors and other signals that manipulate the regulatory processes of the cell. In plants, an unusual signal-light-is required for the induction and regulation of many developmental processes. Past physiological and molecular studies have revealed the variety and complexity of plant responses to light but until recently very little was known about the mechanisms of those responses. Two major breakthroughs have allowed the identification of some photoreceptor signalling intermediates: the identification of photoreceptor and signal transduction mutants in Arabidopsis, and the development of single-cell microinjection assays in which outcomes of photoreceptor signalling can be visualized. Here, we review recent genetic advances which support the notion that light responses are not simply endpoints of linear signal transduction pathways, but are the result of the integration of a variety of input signals through a complex network of interacting signalling components.

Mutations in the gene for the red/far-red light receptor phytochrome B alter cell elongation and physiological responses throughout Arabidopsis development

Phytochromes are a family of plant photoreceptors that mediate physiological and developmental responses to changes in red and far-red light conditions. In Arabidopsis, there are genes for at least five phytochrome proteins. These photoreceptors control such responses as germination, stem elongation, flowering, gene expression, and chloroplast and leaf development. However, it is not known which red light responses are controlled by which phytochrome species, or whether the different phytochromes have overlapping functions. We report here that previously described hy3 mutants have mutations in the gene coding for phytochrome B (PhyB). These are the first mutations shown to lie in a plant photoreceptor gene. A number of tissues are abnormally elongated in the hy3(phyB) mutants, including hypocotyls, stems, petioles, and root hairs. In addition, the mutants flower earlier than the wild type, and they accumulate less chlorophyll. PhyB thus controls Arabidopsis development at numerous stages and in multiple tissues.

Suppression of the ndv mutant phenotype of Rhizobium meliloti by cloned exo genes

The ndvA and ndvB genes of Rhizobium meliloti are involved in the export and synthesis, respectively, of the small cyclic polysaccharide beta(1,2)glucan. We have previously shown that spontaneous symbiotic pseudorevertants of ndv mutants do not produce periplasmic beta(1,2)glucan. Here we show that the pseudorevertants also do not produce extracellular beta(1,2)glucan, but do show alterations in the amount of the major acidic exopolysaccharide produced. This exopolysaccharide is not detectably different from that produced by the wild type or by the ndv mutants. A cosmid which suppresses the symbiotic defect of both ndvA and ndvB mutants was isolated from a gene bank prepared from DNA of an ndvA pseudorevertant. This cosmid contains a number of exo genes, including exoH and exoF. Subcloning and Tn5 mutagenesis were used to show that the widely separated exoH and exoF genes are both involved in suppression of the ndv mutant phenotype and that the 3.5 kb DNA fragment which contains the exoH gene does not carry the mutation responsible for second site suppression.

Phenotypic and Genetic Analysis of det2, a New Mutant That Affects Light-Regulated Seedling Development in Arabidopsis

The greening phenotypes produced by recessive mutations in a gene designated de-etiolated-2 (DET2) are described. Recessive mutations in the DET2 gene uncouple light signals from a number of light-dependent processes. det2 mutations result in dark-grown Arabidopsis thaliana seedlings with many characteristics of light-grown plants, including hypocotyl growth inhibition, cotyledon expansion, primary leaf initiation, anthocyanin accumulation, and derepression of light-regulated gene expression. In contrast to these morphological and gene expression changes, however, the chloroplast development program is not initiated in the dark in det2 mutants, suggesting that light-regulated gene expression precedes the differentiation of etioplasts to chloroplasts. det2 mutations thus reveal at least two classes of downstream light-regulated responses that differ in their timing and control mechanisms. Homozygous det2 mutations also affect photoperiodic responses in light-grown plants, including timing of flowering, dark adaptation of gene expression, and onset of leaf senescence. The phenotype of det1 det2 double mutants is additive, implying that DET1 and DET2 function in distinct pathways that affect downstream light-regulated genes. Furthermore, these pathways are not utilized solely during early seedling development but must also be required to regulate different aspects of the light developmental program during later stages of vegetative growth.

Phenotypic and Genetic Analysis of det2, a New Mutant That Affects Light-Regulated Seedling Development in Arabidopsis

The greening phenotypes produced by recessive mutations in a gene designated de-etiolated-2 (DET2) are described. Recessive mutations in the DET2 gene uncouple light signals from a number of light-dependent processes. det2 mutations result in dark-grown Arabidopsis thaliana seedlings with many characteristics of light-grown plants, including hypocotyl growth inhibition, cotyledon expansion, primary leaf initiation, anthocyanin accumulation, and derepression of light-regulated gene expression. In contrast to these morphological and gene expression changes, however, the chloroplast development program is not initiated in the dark in det2 mutants, suggesting that light-regulated gene expression precedes the differentiation of etioplasts to chloroplasts. det2 mutations thus reveal at least two classes of downstream light-regulated responses that differ in their timing and control mechanisms. Homozygous det2 mutations also affect photoperiodic responses in light-grown plants, including timing of flowering, dark adaptation of gene expression, and onset of leaf senescence. The phenotype of det1 det2 double mutants is additive, implying that DET1 and DET2 function in distinct pathways that affect downstream light-regulated genes. Furthermore, these pathways are not utilized solely during early seedling development but must also be required to regulate different aspects of the light developmental program during later stages of vegetative growth.

Symbiotic pseudorevertants of Rhizobium meliloti ndv mutants

Nodule development (ndv) mutants of Rhizobium meliloti cannot invade alfalfa to establish a nitrogen-fixing symbiosis and instead induce the formation of small, white, unoccupied nodules on alfalfa roots. Such mutants also fail to produce the unusual cyclic oligosaccharide beta-(1----2)-glucan and show defects in several aspects of vegetative growth and function. Here we show that ndv mutants are severely reduced, although not totally deficient, in the ability to attach to and initiate infection threads on alfalfa seedlings, and we demonstrate that the symbiotic deficiency can be separated from the rest of the mutant phenotype by isolating second-site pseudorevertants. Pseudorevertants selected for restoration of motility, a vegetative property, regained a substantial amount of attachment capability but only slight infection thread initiation and symbiotic ability. Such strains also regained partial tolerance to growth at low osmolarity, even though they did not recover the ability to synthesize periplasmic beta-(1----2)-glucan. Pseudorevertants selected on alfalfa for restoration of symbiosis were unrestored for beta-(1----2)-glucan production or any other vegetative property and regained little or no attachment or infection thread initiation capability. We take these data to indicate that wild-type R. meliloti normally has considerable excess capability for both attachment and infection thread initiation and that the symbiotic block in ndv mutants lies further along the developmental pathway than either of these processes, probably at the level of infection thread extension. Further, the fact that neither type of pseudorevertant recovered the ability to produce periplasmic beta-(1----2)-glucan raises the possibility that this oligosaccharide is not directly required for nodule development.

Multiple chromosomes of Azotobacter vinelandii

The number of copies of the genes leuB, nifH, nifD, and nifK per cell of Azotobacter vinelandii has been determined to be about 80. A beta-lactamase gene was integrated into the A. vinelandii chromosome by single-point crossover. Subsequently, we have been able to detect nearly 80 copies of this beta-lactamase gene per cell of A. vinelandii when cultured for a large number of generations in the presence of ampicillin. The multiple copies of the beta-lactamase gene do not seem to be present on a single chromosome, as evident from the fragment obtained by digestion of cellular DNA with the appropriate restriction endonuclease. The kinetics of renaturation of DNA of A. vinelandii is suggestive of complexity similar to that of Escherichia coli. The DNA content of A. vinelandii, however, is 40 times that of E. coli. All these indicate the presence of multiple chromosomes, possibly as many as 80, in A. vinelandii.