The nuclear transport factor CSE1 drives macronuclear volume increase and macronuclear node coalescence in Stentor coeruleus

Stentor coeruleus provides a unique opportunity to study how cells regulate nuclear shape because its macronucleus undergoes a rapid, dramatic, and developmentally regulated shape change. We found that the volume of the macronucleus increases during coalescence, suggesting an inflation-based mechanism. When the nuclear transport factor, CSE1, is knocked down by RNAi, the shape and volume changes of the macronucleus are attenuated, and nuclear morphology is altered. CSE1 protein undergoes a dynamic relocalization correlated with nuclear shape changes, being mainly cytoplasmic prior to nuclear coalescence, and accumulating inside the macronucleus during coalescence. At the end of regeneration, CSE1 protein levels are reduced as the macronucleus returns to its pre-coalescence volume. We propose a model in which nuclear transport via CSE1 is required to increase the volume of the macronucleus, thereby decreasing the surface-to-volume ratio and driving coalescence of the nodes into a single mass.

Modular, cascade-like transcriptional program of regeneration in Stentor

The giant ciliate Stentor coeruleus is a classical model system for studying regeneration and morphogenesis in a single cell. The anterior of the cell is marked by an array of cilia, known as the oral apparatus, which can be induced to shed and regenerate in a series of reproducible morphological steps, previously shown to require transcription. If a cell is cut in half, each half regenerates an intact cell. We used RNA sequencing (RNAseq) to assay the dynamic changes in Stentor’s transcriptome during regeneration, after both oral apparatus shedding and bisection, allowing us to identify distinct temporal waves of gene expression including kinases, RNA -binding proteins, centriole biogenesis factors, and orthologs of human ciliopathy genes. By comparing transcriptional profiles of different regeneration events, we identified distinct modules of gene expression corresponding to oral apparatus regeneration, posterior holdfast regeneration, and recovery after wounding. By measuring gene expression after blocking translation, we show that the sequential waves of gene expression involve a cascade mechanism in which later waves of expression are triggered by translation products of early-expressed genes. Among the early-expressed genes, we identified an E2F transcription factor and the RNA-binding protein Pumilio as potential regulators of regeneration based on the expression pattern of their predicted target genes. RNAi-mediated knockdown experiments indicate that Pumilio is required for regenerating oral structures of the correct size. E2F is involved in the completion of regeneration but is dispensable for earlier steps. This work allows us to classify regeneration genes into groups based on their potential role for regeneration in distinct cell regeneration paradigms, and provides insight into how a single cell can coordinate complex morphogenetic pathways to regenerate missing structures.

Determining protein polarization proteome-wide using physical dissection of individual Stentor coeruleus cells

Cellular components are non-randomly arranged with respect to the shape and polarity of the whole cell.^1-4 Patterning within cells can extend down to the level of individual proteins and mRNA.^5,6 But how much of the proteome is actually localized with respect to cell polarity axes? Proteomics combined with cellular fractionation^7-11 has shown that most proteins localize to one or more organelles but does not tell us how many proteins have a polarized localization with respect to the large-scale polarity axes of the intact cell. Genome-wide localization studies in yeast^12-15 found that only a few percent of proteins have a localized position relative to the cell polarity axis defined by sites of polarized cell growth. Here, we describe an approach for analyzing protein distribution within a cell with a visibly obvious global patterning-the giant ciliate Stentor coeruleus.^16,17 Ciliates, including Stentor, have highly polarized cell shapes with visible surface patterning.^1,18 A Stentor cell is roughly 2 mm long, allowing a "proteomic dissection" in which microsurgery is used to separate cellular fragments along the anterior-posterior axis, followed by comparative proteomic analysis. In our analysis, 25% of the proteome, including signaling proteins, centrin/SFI proteins, and GAS2 orthologs, shows a polarized location along the cell's anterior-posterior axis. We conclude that a large proportion of all proteins are polarized with respect to global cell polarity axes and that proteomic dissection provides a simple and effective approach for spatial proteomics.

An evaluation of patient outcomes following transcatheter pulmonary valve implantation: a meta-analysis

Background

Transcatheter pulmonary valve implantation has emerged as an effective alternative to surgery in patients with congenital Right Ventricular Outflow Tract Dysfunction (RVOT). There is demonstrable evidence that Percutaneous Pulmonary Valve Implantation (PPVI) effectively restores conduit graft viability with a consequent improvement in right ventricular pressures.

Aim

The objective of this study was to perform a meta-analysis of all previously published studies examining the outcome of PPVI and the associated early and late peri-procedural factors in patients with RVOT dysfunction. Data from procedures performed within our own centre have also been included.

Methodology

We performed a meta-analysis of all observational studies investigating early and late outcomes following PPVI. Risk ratios and risk differences were pooled in a random-effects model. The I2 statistic was used to quantify heterogeneity between studies. We searched EMBASE, MEDLINE, CINAHL, PsychInfo and Cochrane databases from their inception until 2021. Studies were included if they reported any comparative data regarding study endpoints. Primary endpoint was mean RVOT gradient. Secondary end points include pulmonary regurgitation fraction, left and right ventricular end-diastolic and systolic volume indexes, and left ventricular ejection fraction. Complication rates were considered a safety endpoint.

Results

A total of 23 studies with 1501 participants enrolled were included in the final meta-analysis. The RVOT gradient decreased significantly [weighted mean difference (WMD) = −20.32 mmHg; 95% confidence interval (CI): −22.15, −19.11; p<0.001]. Mean right ventricular (RV) systolic pressures fell significantly [(WMD)= −18.4 mmHg; 95% CI: −16.4, −20.2; p<0.001) and RV diastolic pressures decreased significantly [(WMD) = −6.3 mmHg, 95% CI: −4.3, −8.9; p<0.001). Pulmonary regurgitation fraction (PRF) also decreased notably (WMD = −24.38%, 95% CI: −28.27, −17.32; p<0.001).The incidence of infective endocarditis was 1.8% (95% CI: 0.7–3.8).

Conclusion

PPVI is an effective and safe strategy in relieving right ventricular remodelling and improving haemodynamic and clinical outcomes in patients with RVOT dysfunction. Multi-centre collaborations are essential to further determine the long-term effects of PPVI on cardiac function, exercise tolerance and quality of life in RVOT dysfunction.

Funding Acknowledgement

Type of funding sources: None.

Predictors of response to pulmonary rehabilitation in stable chronic obstructive pulmonary disease patients: A prospective cohort study

Context:

Pulmonary rehabilitation (PR) has become a standard of care in the management of chronic obstructive pulmonary disease (COPD). However, a significant proportion of the patients do not show benefit after the PR program.

Aims:

The study was planned to find different patient- and/or disease-related factors that may predict response to PR in stable COPD.

Subjects and Methods:

A total of 102 stable COPD patients were prospectively enrolled. Baseline evaluation and investigations, including spirometry, arterial blood gas analysis, and bone mineral density assessment, were done. Thereafter, all patients underwent an 8-week comprehensive outpatient PR program that consisted of exercise training, education, nutritional, and psychological counseling. The response to PR was dichotomously (yes/no) defined by the combined improvement in exercise tolerance (6-min walk distance [6MWD] +54 m) and quality of life (St. George's Respiratory Questionnaire [SGRQ] score - 4 points) measured before and after the program. Thereafter, different predefined factors were analyzed for their possible association with the PR response.

Results:

A total of 80 patients (78.4%) completed the PR program and were subjected for analysis. Out of them, 42 (52.5%) showed improvement in both 6MWD and SGRQ score (46 in 6MWD and 54 in SGRQ score). After application of multivariate logistic regression analysis, forced expiratory volume in 1 s <50% predicted (odds ratio [OR]: 2.9; 95% confidence interval [CI]: 1.1–8.3; P = 0.04) and osteoporosis (OR: 0.26; 95% CI: 0.13–0.53; P < 0.001) were found as independent factors predicting PR efficacy.

Conclusions:

Poor baseline lung function predicts a short-term improvement in exercise capacity and quality of life in COPD patients, whereas osteoporosis is a negative predictor of PR response. Active search for these factors may help in better patient selection, thus leading to improved outcome after PR.

Microfluidic guillotine for single-cell wound repair studies

Wound repair is a key feature distinguishing living from nonliving matter. Single cells are increasingly recognized to be capable of healing wounds. The lack of reproducible, high-throughput wounding methods has hindered single-cell wound repair studies. This work describes a microfluidic guillotine for bisecting single Stentor coeruleus cells in a continuous-flow manner. Stentor is used as a model due to its robust repair capacity and the ability to perform gene knockdown in a high-throughput manner. Local cutting dynamics reveals two regimes under which cells are bisected, one at low viscous stress where cells are cut with small membrane ruptures and high viability and one at high viscous stress where cells are cut with extended membrane ruptures and decreased viability. A cutting throughput up to 64 cells per minute-more than 200 times faster than current methods-is achieved. The method allows the generation of more than 100 cells in a synchronized stage of their repair process. This capacity, combined with high-throughput gene knockdown in Stentor, enables time-course mechanistic studies impossible with current wounding methods.

Non-model model organisms

Model organisms are widely used in research as accessible and convenient systems to study a particular area or question in biology. Traditionally only a handful of organisms have been widely studied, but modern research tools are enabling researchers to extend the set of model organisms to include less-studied and more unusual systems. This Forum highlights a range of 'non-model model organisms' as emerging systems for tackling questions across the whole spectrum of biology (and beyond), the opportunities and challenges, and the outlook for the future.

The Macronuclear Genome of Stentor coeruleus Reveals Tiny Introns in a Giant Cell

The giant, single-celled organism Stentor coeruleus has a long history as a model system for studying pattern formation and regeneration in single cells. Stentor [1, 2] is a heterotrichous ciliate distantly related to familiar ciliate models, such as Tetrahymena or Paramecium. The primary distinguishing feature of Stentor is its incredible size: a single cell is 1 mm long. Early developmental biologists, including T.H. Morgan [3], were attracted to the system because of its regenerative abilities-if large portions of a cell are surgically removed, the remnant reorganizes into a normal-looking but smaller cell with correct proportionality [2, 3]. These biologists were also drawn to Stentor because it exhibits a rich repertoire of behaviors, including light avoidance, mechanosensitive contraction, food selection, and even the ability to habituate to touch, a simple form of learning usually seen in higher organisms [4]. While early microsurgical approaches demonstrated a startling array of regenerative and morphogenetic processes in this single-celled organism, Stentor was never developed as a molecular model system. We report the sequencing of the Stentor coeruleus macronuclear genome and reveal key features of the genome. First, we find that Stentor uses the standard genetic code, suggesting that ciliate-specific genetic codes arose after Stentor branched from other ciliates. We also discover that ploidy correlates with Stentor's cell size. Finally, in the Stentor genome, we discover the smallest spliceosomal introns reported for any species. The sequenced genome opens the door to molecular analysis of single-cell regeneration in Stentor.

Commercially available immunoglobulins contain virus neutralizing antibodies against all major genotypes of polyomavirus BK

Neutralizing antibodies (NAbs) form the basis of immunotherapeutic strategies against many important human viral infections. Accordingly, we studied the prevalence, titer, genotype-specificity, and mechanism of action of anti-polyomavirus BK (BKV) NAbs in commercially available human immune globulin (IG) preparations designed for intravenous (IV) use. Pseudovirions (PsV) of genotypes Ia, Ib2, Ic, II, III, and IV were generated by co-transfecting a reporter plasmid encoding luciferase and expression plasmids containing synthetic codon-modified VP1, VP2, and VP3 capsid protein genes into 293TT cells. NAbs were measured using luminometry. All IG preparations neutralized all BKV genotypes, with mean EC50 titers as high as 254 899 for genotype Ia and 6,666 for genotype IV. Neutralizing titers against genotypes II and III were higher than expected, adding to growing evidence that infections with these genotypes are more common than currently appreciated. Batch to batch variation in different lots of IG was within the limits of experimental error. Antibody mediated virus neutralizing was dose dependent, modestly enhanced by complement, genotype-specific, and achieved without effect on viral aggregation, capsid morphology, elution, or host cell release. IG contains potent NAbs capable of neutralizing all major BKV genotypes. Clinical trials based on sound pharmacokinetic principles are needed to explore prophylactic and therapeutic applications of these anti-viral effects, until effective small molecule inhibitors of BKV replication can be developed.

Behavioral and hormonal pattern of repeat breeder cows around estrus

Repeat breeder (RB) cows were compared with normal (CTRL) ones with respect to behavioral estrus intensity, endocrine patterns and concentrations of plasma estradiol, progesterone and LH around estrus, and ovulation timing. A total of 27 and 31 cycles in 12 RB and 18 CTRL cows, respectively, were synchronized by means of the Ovsynch protocol followed by a single PG injection after 7 days. Behavioral estrus and ovulation were observed in 81.5 and 83.8% of the synchronized cycles in the RB and CTRL cows respectively. The RB and CTRL groups had similar estrus durations of 21.4 and 19.6 h respectively, but estrus was more intense in the RB, as indicated by numerically higher overall activity indexes and higher peak neck activity. The interval from PG injection to estrus onset (considered as proestrus) was 8.2 h shorter in RB than in CTRL cows, at 47.9 and 56.1 h respectively (P<0.007), but the average preovulatory follicle size was similar. The estradiol concentration at peak was numerically higher (21%) and the AUC tended to be higher in the RB cows than in the CTRL cows. LH secretion during the period from 18 to 3 h before the LH peak was also lower in RB than in CTRL cows: 2.5 and 4.6 ng/ml respectively (P<0.01). In conclusion, the behavioral estrus was more intense in the RB cows; nevertheless, short proestrus and subdued LH concentrations before the LH peak, which could impair oocyte competence and development, were first reported in RB cows.

Matrix-assisted laser desorption ionization time-of-flight mass spectrometry for the rapid identification of yeasts causing bloodstream infections

Few studies have systematically standardised and evaluated matrix-assisted laser desorption ionization time-of-flight mass spectrometry (MALDI-TOF MS) for identification of yeasts from bloodstream infections. This is rapidly becoming pertinent for early identification of yeasts and appropriate antifungal therapy. We used 354 yeast strains identified by polymerase chain reaction (PCR) sequencing for standardisation and 367 blind clinical strains for validation of our MALDI-TOF MS protocols. We also evaluated different sample preparation methods and found the on-plate formic acid extraction method as most cost- and time-efficient. The MALDI-TOF assay correctly identified 98.9% of PCR-sequenced yeasts. Novel main spectrum projections (MSP) were developed for Candida auris, C. viswanathii and Kodamaea ohmeri, which were missing from the Bruker MALDI-TOF MS database. Spectral cut-offs computed by receiver operating characteristics (ROC) analysis showed 99.4% to 100% accuracy at a log score of ≥ 1.70 for C. tropicalis, C. parapsilosis, C. pelliculosa, C. orthopsilosis, C. albicans, C. rugosa, C. guilliermondii, C. lipolytica, C. metapsilosis, C. nivariensis. The differences in the species-specific scores of our standardisation and blind validation strains were not statistically significant, implying the optimal performance of our test protocol. The MSPs of the three new species also were validated. We conclude that MALDI-TOF MS is a rapid, accurate and reliable tool for identification of bloodstream yeasts. With proper standardisation, validation and regular database expansion, its efficiency can be further enhanced.

A diabetes scorecard does not improve HbA(1c), blood pressure, lipids, aspirin usage, exercise and diabetes knowledge over 9 months: a randomized controlled trial

AIMS

To test (1) whether a diabetes scorecard can improve glycaemic control, blood pressure control, LDL cholesterol, aspirin usage and exercise; (2) if the scorecard will motivate and/or educate patients to improve their scores for subsequent visits; and (3) whether the scorecard will improve rates of clinical inertia.

METHODS

Five physicians enrolled 103 patients ≥ 40 years old with uncontrolled Type 2 diabetes [HbA(1c) ≥ 64 mmol/mol (8.0%)] to randomly receive either a diabetes scorecard or not during four clinical visits over a 9-month period. The population was predominantly urban with a disproportionately higher percentage of black people than the general population. Our scorecard assigned points to six clinical variables, with a perfect total score of 100 points corresponding to meeting all targets. The primary outcomes were total scores and HbA(1c) in the scorecard and control groups at 9 months.

RESULTS

There were no significant differences between the control and scorecard groups at visits 1 and 4 in total score, HbA(1c) , blood pressure, LDL cholesterol, aspirin usage, exercise or knowledge about diabetic targets. By visit 4 both the control and scorecard groups had statistically significant improvements with their mean total score (9 and 7 points, respectively), HbA(1c) [-9 mmol/mol (-0.8%) and -15 mmol/mol (-1.4%), respectively] and aspirin usage (33% increase and 16% increase, respectively). Rates of clinical inertia were low throughout the study.

CONCLUSIONS

A diabetes scorecard did not improve glycaemic control, blood pressure control, LDL cholesterol, aspirin usage, exercise or diabetic knowledge in an urban population with uncontrolled Type 2 diabetes.

Stochastic de-repression of Rhodopsins in single photoreceptors of the fly retina

The photoreceptors of the Drosophila compound eye are a classical model for studying cell fate specification. Photoreceptors (PRs) are organized in bundles of eight cells with two major types – inner PRs involved in color vision and outer PRs involved in motion detection. In wild type flies, most PRs express a single type of Rhodopsin (Rh): inner PRs express either Rh3, Rh4, Rh5 or Rh6 and outer PRs express Rh1. In outer PRs, the K₅₀ homeodomain protein Dve is a key repressor that acts to ensure exclusive Rh expression. Loss of Dve results in de-repression of Rhodopsins in outer PRs, and leads to a wide distribution of expression levels. To quantify these effects, we introduce an automated image analysis method to measure Rhodopsin levels at the single cell level in 3D confocal stacks. Our sensitive methodology reveals cell-specific differences in Rhodopsin distributions among the outer PRs, observed over a developmental time course. We show that Rhodopsin distributions are consistent with a two-state model of gene expression, in which cells can be in either high or basal states of Rhodopsin production. Our model identifies a significant role of post-transcriptional regulation in establishing the two distinct states. The timescale for interconversion between basal and high states is shown to be on the order of days. Our results indicate that even in the absence of Dve, the Rhodopsin regulatory network can maintain highly stable states. We propose that the role of Dve in outer PRs is to buffer against rare fluctuations in this network.

Complex networks of genetic interactions govern the development of multicellular organisms. One of the best-characterized networks governs the development of the fruit-fly retina, a highly organized, three-dimensional organ composed of a hexagonal grid of eight types of photoreceptor neurons. Each photoreceptor responds to a particular wavelength of light depending on the Rhodopsin protein it expresses. We present novel computational methods to quantify cell-specific Rhodopsin levels from confocal microscopy images. We apply these methods to study the effect of the loss of a key repressor that ensures each photoreceptor expresses only one Rhodopsin. We show that this perturbation has cell-specific effects. Our measurement of the cell-type specific Rhodopsin distributions reveals differences between photoreceptor cells, which could not otherwise be detected. Using mathematical models of gene expression, we attribute this variability to stochastic events that activate Rhodopsin production.

Interlocked feedforward loops control cell-type-specific Rhodopsin expression in the Drosophila eye

How complex networks of activators and repressors lead to exquisitely specific cell-type determination during development is poorly understood. In the Drosophila eye, expression patterns of Rhodopsins define at least eight functionally distinct though related subtypes of photoreceptors. Here, we describe a role for the transcription factor gene defective proventriculus (dve) as a critical node in the network regulating Rhodopsin expression. dve is a shared component of two opposing, interlocked feedforward loops (FFLs). Orthodenticle and Dve interact in an incoherent FFL to repress Rhodopsin expression throughout the eye. In R7 and R8 photoreceptors, a coherent FFL relieves repression by Dve while activating Rhodopsin expression. Therefore, this network uses repression to restrict and combinatorial activation to induce cell-type-specific expression. Furthermore, Dve levels are finely tuned to yield cell-type- and region-specific repression or activation outcomes. This interlocked FFL motif may be a general mechanism to control terminal cell-fate specification.

Acute renal failure caused by pheniramine maleate induced rhabdomyolysis: an unusual case

Antihistamines are easily available over-the-counter medications, which are frequently involved in overdoses. The usual course is accompanied by the anticholinergic effects of these agents. We report a case of a suicide attempt in a young male, where ingestion of antihistamine pheniramine maleate was complicated by nontraumatic rhabdomyolysis and oliguric acute renal failure. Rhabdomyolysis and acute renal failure is a rarely reported but potentially serious complication among patients who present to the emergency after intentional overdoses making recognition and prompt intervention essential. We also describe the potential mechanism of muscle injury in antihistamine overdose.

Skunk and psychosis in South East London

Background:

Epidemiological studies have reported that the increased risk of developing psychosis in cannabis users is dose related. In addition, experimental research has shown that the active constituent of cannabis responsible for its psychotogenic effect is Delta-9-Tetrahydrocannabinol (THC) (Murray et al, 2007). Recent evidence has suggested an increased in potency (% TCH) in the cannabis seized in the UK (Potter et al, 2007).

Hypothesis:

We predicted that first episode psychosis patients are more likely to use higher potency cannabis and more frequently than controls.

Methods:

We collected information concerning socio-demographic, clinical characteristics and cannabis use (age at first use, frequency, length of use, type of cannabis used) from a sample of 191 first-episode psychosis patients and 120 matched healthy volunteers. All were recruited as part of the Genetic and Psychosis (GAP) study which studied all patients who presented to the South London and Maudsley Trust.

Results:

There was no significant difference in the life-time prevalence of cannabis use or age at first use between cases and controls. However, cases were more likely to be regular users (p=0.05), to be current users (p=0.04) and to have smoked cannabis for longer (p=0.01). Among cannabis users, 86.8% of 1st Episode Psychosis Patients preferentially used Skunk/Sinsemilla compared to 27.7% of Controls. Only 13.2 % of 1st Episode psychosis Patients chose to use Resin/Hash compared to 76.3% of controls. The concentration of TCH in these in South East London, ranges between 8.5 and 14 % (Potter et al, 2007). Controls (47%) were more likely to use Hash (Resin) whose average TCH concentration is 3.4% (Potter et al, 2007).

Conclusions:

Patients with first episode psychosis have smoked higher potency cannabis, for longer and with greater frequency, than healthy controls.

Pharmaceutical development, quality control, stability and compatibility of a parenteral lyophilized formulation of the investigational polymer-conjugated platinum antineoplastic agent AP5346

AP5346 is a low molecular weight polymer-conjugated platinum antineoplastic agent. The lyophilized drug product has completed a phase I clinical trial. In order to guarantee a constant quality of AP5346 pharmaceutical products, quality control and analysis of the drug substance and final product were performed. The identity of AP5346 was confirmed using 1H NMR, 195Pt NMR and IR spectroscopy. Furthermore, the free platinum content, platinum release characteristics, molecular size and size distribution were established. With the selected analytical techniques, AP5346 could be distinguished very well from its polymeric analogues, such as AP5280 and AP5279. Stability experiments revealed that AP5346 final product is stable for 12 months at 5 degrees C, in the dark. For administration to patients, AP5346 final product is reconstituted with 5% w/v dextrose and diluted in infusion containers. To investigate the influence of container materials, the stability of AP5346 after reconstitution and dilution in infusion containers was determined. The infusion containers investigated were composed of glass, polyvinyl chloride (PVC, intraflex) and low density polyethylene (LD-PE, Ecoflac). AP5346 was shown to be stable after reconstitution and dilution with 5% w/v dextrose in these infusion containers for at least 96 h at 2-8 degrees C in the dark and at room temperature with ambient light conditions.

Cell-type-specific signatures of microRNAs on target mRNA expression

Although it is known that the human genome contains hundreds of microRNA (miRNA) genes and that each miRNA can regulate a large number of mRNA targets, the overall effect of miRNAs on mRNA tissue profiles has not been systematically elucidated. Here, we show that predicted human mRNA targets of several highly tissue-specific miRNAs are typically expressed in the same tissue as the miRNA but at significantly lower levels than in tissues where the miRNA is not present. Conversely, highly expressed genes are often enriched in mRNAs that do not have the recognition motifs for the miRNAs expressed in these tissues. Together, our data support the hypothesis that miRNA expression broadly contributes to tissue specificity of mRNA expression in many human tissues. Based on these insights, we apply a computational tool to directly correlate 3' UTR motifs with changes in mRNA levels upon miRNA overexpression or knockdown. We show that this tool can identify functionally important 3' UTR motifs without cross-species comparison.

A genome-wide map of conserved microRNA targets in C. elegans

BACKGROUND

Metazoan miRNAs regulate protein-coding genes by binding the 3' UTR of cognate mRNAs. Identifying targets for the 115 known C. elegans miRNAs is essential for understanding their function.

RESULTS

By using a new version of PicTar and sequence alignments of three nematodes, we predict that miRNAs regulate at least 10% of C. elegans genes through conserved interactions. We have developed a new experimental pipeline to assay 3' UTR-mediated posttranscriptional gene regulation via an endogenous reporter expression system amenable to high-throughput cloning, demonstrating the utility of this system using one of the most intensely studied miRNAs, let-7. Our expression analyses uncover several new potential let-7 targets and suggest a new let-7 activity in head muscle and neurons. To explore genome-wide trends in miRNA function, we analyzed functional categories of predicted target genes, finding that one-third of C. elegans miRNAs target gene sets are enriched for specific functional annotations. We have also integrated miRNA target predictions with other functional genomic data from C. elegans.

CONCLUSIONS

At least 10% of C. elegans genes are predicted miRNA targets, and a number of nematode miRNAs seem to regulate biological processes by targeting functionally related genes. We have also developed and successfully utilized an in vivo system for testing miRNA target predictions in likely endogenous expression domains. The thousands of genome-wide miRNA target predictions for nematodes, humans, and flies are available from the PicTar website and are linked to an accessible graphical network-browsing tool allowing exploration of miRNA target predictions in the context of various functional genomic data resources.

Sclerotinia Root Rot: A New Threat to Buckwheat Seedlings in India

In the temperate regions of India, buckwheat (Fagopyrum esculentum Moench and F. tataricum Gaertn.) is produced extensively. During the first week of June in 2001 and 2002, a severe incidence of root rot (35% seedling mortality) was observed in the Sangla Valley of Himachal Pradesh when the crop was at the seedling stage. The disease was more severe on F. tataricum, resulting in a poor crop stand. The disease appeared as water-soaked areas on the upper portion of the root, which turned brown. The brown patches gradually proceeded downward covering the whole root system. The above ground foliage wilted and died. The disease spread rapidly with cloudy, humid weather and day temperatures ranging from 15 to 20°C. Mycelium of the causal fungus was inter- and intracellular type with hyaline, branched, and septate hyphae. Sclerotia were pink but later turned black, measuring 3.0 to 3.5 mm in diameter. The pathogenicity of the causal fungus was proved following Koch's postulates. The pathogen was identified as Sclerotinia sclerotiorum (Lib.) de Bary (2). In Japan, the association of S. libertiana on buckwheat has been reported (1). To our knowledge, this is the first report of Sclerotinia root rot on buckwheat from India. References: (1) H. Singh and T. A. Thomas. Indian Counc. Agric. Res. New Delhi, India, 1978. (2) H. J. Willets and J. A. L. Wong, Bot. Rev. 46:101,1980.

Brain abscess due to Xylohypha bantiana

A case of brain abscess due to Xylohypha bantiana without any obvious predisposing factors and with the uncommon clinical feature of seizures is presented.

Mitral valve endocarditis following balloon mitral valvotomy

The case of a patient who developed fungal valve endocarditis due to Candida albicans following balloon mitral valvotomy is presented. The patient did not have any obvious predisposing factors which led to the development of fungal endocarditis.

Candidemia in neonatal intensive care unit

The present study was conducted over a period of 6 months to determine the Candida species causing candidemia in a neonatal intensive care unit and to analyse the risk factors associated with acquisition of significant fungemia. Speciation of the 19 isolated Candida spp was done by the standard techniques. Antimicrobial susceptibility of these isolates was determined by disc diffusion method against Amphotericin B, Fluconazole, Ketoconozole and 5-Flucytosine. Candida glabrata was the most common species involved (42.1%). Other species isolated were C. tropicalis (31.6%). Calbicans (21.1%) and C.parapsilosis (5.2%). All the isolates were sensitive to Amphotericin B. Resistance to other antigungal agents was seen only in C. globrata. Significant candidemia was seen in 14/19 (72.6%) of neonates. Risk factors found to be associated with significant candidemis in these neonates included intake of multiple broad-spectrum antibiotics (p<0.0001), use of total parenteral nutrition (p<0.045) and ventilators (p<0.0001).

Potential infection hazards of stethoscopes

This study was conducted to assess the bacterial flora carried on stethoscopes used by medical personnel and to study the effect of disinfection of stethoscopes on the flora. In the 106 stethoscopes sampled, Gram-positive organisms were the most (60%) frequently isolated. Among them, Staphylococcus aureus accounted for 15.8% of the flora of which 21% were resistant to methicillin. The rate of isolation of S aureus and methicillin resistant S aureus (MRSA) was higher in critical care units. Disinfection was found to significantly reduce the bacterial count.

Malingering and symptom magnification: a case report illustrating the limitations of clinical judgement

Malingering and symptom embellishment are of concern to specialists in pain medicine. Valid criteria to identify malingering individuals suffering chronic pain do not exist. We present a case of a patient on worker's compensation identified as a malingerer by six different physicians who had evaluated the patient for her chronic complaints. Ultimately, she was found to have a lesion that explained all of her subjective complaints. Physicians should exercise caution in labeling patients suffering intractable pain as malingerers.

Postantibiotic effect of a combination of antimicrobial agents on pseudomonas aeruginosa

Treatment of severe Pseudomonas infections often calls for multidrug therapy. Combinations of aminoglycosides, beta-lactams and/or quinolones are generally administered, the effect of which may be additive, synergistic or indifferent. The present in vitro study was designed to find out the exact outcome of the postantibiotic effect (PAE). The minimal inhibitory concentrations and the PAE of three antibiotics (amikacin, ceftazidime and ciprofloxacin) were determined both singly and in combination. Ceftazidime alone exhibited a negative PAE but a synergistic effect was observed for the combination of ceftazidime with amikacin. The combination of ceftazidime with ciprofloxacin and ciprofloxacin with amikacin however gave an indifferent PAE. This synergistic PAE of amikacin with ceftazidime has a significant effect on designing optimal dosage regimens.

Comparison of Vitek Yeast Biochemical Card with conventional methods for speciation of Candida

The ability of the Vitek Yeast Biochemical Card to identify yeast isolates was compared with conventional methods. Of the fifty yeast isolates tested same species identification was obtained in thirty-four isolates. The Vitek yeast biochemical card identified 13 isolates which could not be identified by the conventional tests. Though the Vitek Yeast biochemical card gave a good rapid identification the high cost of each test severely limits its routine use in most of the laboratories.

Central nervous system abnormalities in complex regional pain syndrome (CRPS): clinical and quantitative evidence of medullary dysfunction

OBJECTIVE

Sensory and motor abnormalities are common among patients with complex regional pain syndrome (CRPS). The purpose of the present study was to define and characterize these abnormalities and to develop a hypothesis regarding the area of the central nervous system from which they derive.

DESIGN

Data were acquired from study subjects using clinical examination and quantitative assessment of neurological function. Subjects were divided into four groups. CRPS patients were differentiated into two groups based on the presence or absence of sensory deficit on the face to clinical examination. The other two groups were composed of patients with other chronic pain syndromes and normal individuals without chronic pain or disability. Clinical and quantitative data were compared between groups.

PATIENTS

One hundred forty-five CRPS patients, 69 patients with other pain conditions, and 26 normal individuals were studied.

RESULTS

A high incidence of trigeminal hypoesthesia was observed in CRPS patients. CRPS patients with trigeminal hypoesthesia manifested bilateral deficits of sensory function, with a predominant hemilateral pattern. These patients also manifested bilateral motor weakness with a more prominent hemiparetic pattern. Both sensory and motor deficits were greatest ipsilateral to the painful side of the body. These features differed significantly from those of CRPS patients lacking clinical trigeminal deficit, other pain patients, and normals. A lower cranial nerve abnormality (sternocleidomastoid weakness) and a myelopathic feature (Hoffman's reflex) were more common in CRPS patients with trigeminal hypoesthesia.

CONCLUSIONS

Nearly half of CRPS patients had abnormalities of spinothalamic, trigeminothalamic, and corticospinal function that may represent dysfunction of the medulla. One-third of the remaining CRPS patients had neuroimaging evidence of spinal cord or brain pathology. The majority of CRPS patients in this study have measurable abnormalities of the sensory and motor systems or neuroimaging evidence of spinal cord or brain dysfunction.

Passive smoking, domestic fuels and lung function in north Indian children

A study was carried out in 200 school children from north India to find out the effects of passive smoking and exposure to domestic cooking fuels on their lung functions. Forced vital capacity and FEV1 were the lowest in boys whose households used biomass fuel (p < 0.05) and PEFR and FEF 25% and 50% were lowest in boys with their homes using kerosene as fuels. All these were the best for LPG fuel. However, in girls there was no significant difference in different parameters, although the values were lower in those using kerosene and biomass fuel. All parameters were lower in passive smokers irrespective of the type of fuel used although they were not statistically significant. However, FEF 50% was significantly less in passive smokers whose households used mixed fuels. The same was true for PEFR, PEFR %, and FEF 25% in cases of LPG fuel use.

Respiratory symptoms in Indian children exposed to different cooking fuels

Smoke emission from fuels is an important source of indoor air pollution. Children spend considerable time indoors. It is therefore important to determine whether air contaminants from indoor air sources affect incidence of respiratory illness, cause symptoms and changes in pulmonary function status in them. Two hundred children in the age group of 7-15 were selected randomly. They were stratified according to the fuel used in their homes and respiratory symptoms were inquired from them according to a questionnaire recommended by the American Thoracic Society. The most symptomatic children were those whose households used kerosene (52%) and mixed fuels (46%) although different symptoms were present in varying extent in all 4 groups of children. Cough, cold, congestion or phlegm for one week or more occurred more frequently with mixed fuel use followed by kerosene. The present study thus showed that mixed fuel and kerosene fuel had worst effects on respiratory system in children whose households used these fuels.

Characterization of the autophosphorylation of Era, an essential Escherichia coli GTPase

Era is an essential protein in Escherichia coli which binds both GTP and GDP and has an intrinsic GTPase activity. Studies on the role of GTP/GDP binding and GTPase activity in an attempt to understand its function lead to the observation that Era is autophosphorylated. The autophosphorylation reaction is specific for GTP and cannot use ATP as a phosphoryl group donor. The reaction velocity is of first order with respect to protein concentration, suggesting an intramolecular mechanism. Autophosphorylation occurs at serine and threonine residues. The major phosphorylated tryptic peptide isolated after autophosphorylation has been identified as ISITSR, from residue 33 to 38. The peptide contains the site of phosphorylation and two potential sites for serine and threonine phosphorylation. Subsequently, both the threonine residue at position 36 and the serine residue at position 37 were altered to alanine. The double mutant Era, but not individual single mutants, was unable to functionally complement the growth of an E. coli strain which cannot produce wild-type Era protein at high temperature. This suggests that either threonine 36 or serine 37 has to exist for the function of Era in vivo. In vivo phosphorylation of Era was also examined by two-dimensional gel electrophoresis. Era has been previously assigned two distinct positions having two different X-Y co-ordinates: one of the spots (H032.0) was identified as phosphorylated Era, indicating that a substantial portion of Era in the cell is indeed phosphorylated. Therefore, Era autophosphorylation is likely to play an important physiological role in the cell.(ABSTRACT TRUNCATED AT 250 WORDS)

Cold-sensitive growth and decreased GTP-hydrolytic activity from substitution of Pro17 for Val in Era, an essential Escherichia coli GTPase

A substitution mutation of Pro17 by Val (P17V) was constructed in the guanine nucleotide binding domain of Era, an essential protein in Escherichia coli. The mutation is analogous to the oncogenic activating allele at position 12 in the GTP-binding domain of p21ras. The phenotype of this mutant was analysed in a strain which exclusively expressed the mutant protein (Era-V17) in null allele chromosomal background (era1: :kan). The strain was found to be cold-sensitive for growth. Mutant Era-V17 purified from the strain was cold-sensitive for GTP-hydrolytic activity, suggesting that the GTPase activity of Era is required for cell growth since the P17V mutation resulted in both cold-sensitive growth of cells and cold-labile GTPase activity of the purified protein.

Epilepsy, myasthenia gravis, and effect of plasmapheresis on antiepileptic drug concentrations

A 28-year-old woman developed complex partial seizures at the age of 17 years and was treated with phenytoin sodium. Five years later she developed myasthenia gravis, and phenytoin was replaced by valproic acid and phenobarbital. She required plasmapheresis (PP). During one course of PP, total and unbound concentrations of valproic acid and phenobarbital were measured in serum sampled before, during, and after PP and in plasma removed by PP. It was determined that the magnitude of loss of valproic acid or phenobarbital by PP was small, and the changes of unbound/total ratio did not reach clinical importance.