The accuracy of standard multiple sclerosis MRI brain sequences for the diagnosis of optic neuropathy.

BACKGROUND: Detection of optic neuropathy on MRI has potential implications for the diagnosis and management of Multiple Sclerosis (MS). OBJECTIVE: This study assessed the accuracy of T2 sagittal MRI brain for detection of optic neuropathy, compared to coronal STIR orbit. METHODS AND MATERIALS: Retrospective single-center blinded diagnostic accuracy study of 100 consecutive patients who underwent both T2 sagittal brain and coronal STIR orbit MRI. All were performed on 1.5T scanners. T2 sagittal slice thickness was 4 mm for the first 50 patients (group1) and 3 mm for the second 50 (group2). The MRIs were reviewed in a blinded fashion to determine the presence of optic neuropathy. Coronal STIR orbit sequences were considered the diagnostic reference standard. RESULTS: The sensitivity of T2 sagittal brain imaging for ON was 44% in group 1 and 85% in group 2 (p = 0.007). The specificities were 98% and 97% respectively (p = 0.9). Sensitivity was poorest for evaluation of the intraorbital nerve segment (56% grp1, 69% grp2, p = 0.4). CONCLUSION: T2 sagittal MRI brain has high specificity for the detection of optic neuropathy when compared to coronal STIR orbit. Sensitivity is increased when slice thickness is reduced, but remains poor for evaluation of the intraorbital segment.

The Diagnostic Accuracy of Contrast-Enhanced CT of the Neck for the Investigation of Sialolithiasis.

BACKGROUND AND PURPOSE: Sialolithiasis is a common benign pathology affecting the salivary glands but it is unclear if contrast-enhanced CT, which is commonly used for investigation of head and neck pathology, can identify calculi as accurately as noncontrast CT. The aim of this study was to assess the diagnostic accuracy of contrast-enhanced CT of the neck in the diagnosis of sialolithiasis compared with noncontrast CT of the neck used as the criterion standard. MATERIALS AND METHODS: This was a retrospective, case-control study of 92 consecutive cases in 90 patients who underwent both noncontrast CT of the neck and contrast-enhanced CT of the neck in 2 tertiary referral centers from January 2011 to December 2015 for investigation of sialolithiasis. Axial 3-mm-section images were assessed by a fellowship-trained diagnostic neuroradiologist and diagnostic neuroradiology fellow in consensus. Blinded assessment of the contrast-enhanced CT of the neck was performed first, followed by noncontrast CT of the neck after a 2-week interval. The presence or absence of a stone and stone location and size were documented. Statistical analysis was undertaken to assess the agreement between CT protocols and calculate the sensitivity and specificity of contrast-enhanced CT of the neck. RESULTS: Fifty calculi were identified on noncontrast CT of the neck in 31 cases; and 48 calculi, in 31 cases on contrast-enhanced CT of the neck. No calculi were identified in the remaining 61 cases. The sensitivity and specificity of contrast-enhanced CT of the neck in the detection of sialolithiasis was 96% (95% CI, 86.3%-99.5%) and 100% (95% CI, 94.1%-100%), respectively. The positive predictive value of contrast-enhanced CT of the neck was 100% (95% CI, 92.6%-100%), and the negative predictive value was 96.8% (95% CI, 89%-99.6%). The accuracy of contrast-enhanced CT of the neck in diagnosing the presence or absence of salivary calculi was 98%. CONCLUSIONS: Contrast-enhanced CT of the neck is accurate in the detection of sialolithiasis, with no difference in diagnostic accuracy compared with noncontrast CT of the neck.

A critical review of the potential impacts of marine seismic surveys on fish & invertebrates.

Marine seismic surveys produce high intensity, low-frequency impulsive sounds at regular intervals, with most sound produced between 10 and 300Hz. Offshore seismic surveys have long been considered to be disruptive to fisheries, but there are few ecological studies that target commercially important species, particularly invertebrates. This review aims to summarise scientific studies investigating the impacts of low-frequency sound on marine fish and invertebrates, as well as to critically evaluate how such studies may apply to field populations exposed to seismic operations. We focus on marine seismic surveys due to their associated unique sound properties (i.e. acute, low-frequency, mobile source locations), as well as fish and invertebrates due to the commercial value of many species in these groups. The main challenges of seismic impact research are the translation of laboratory results to field populations over a range of sound exposure scenarios and the lack of sound exposure standardisation which hinders the identification of response thresholds. An integrated multidisciplinary approach to manipulative and in situ studies is the most effective way to establish impact thresholds in the context of realistic exposure levels, but if that is not practical the limitations of each approach must be carefully considered.

Comparative Effectiveness of Imaging Modalities for the Diagnosis of Intestinal Obstruction in Neonates and Infants:: A Critically Appraised Topic.

RATIONALE AND OBJECTIVES: The purpose of this study was to critically appraise and compare the diagnostic performance of imaging modalities that are used for the diagnosis of upper and lower gastrointestinal (GI) tract obstruction in neonates and infants. METHODS: A focused clinical question was constructed and the literature was searched using the patient, intervention, comparison, outcome method comparing radiography, upper GI contrast study, and ultrasound in the detection of upper GI tract obstruction such as duodenal atresia and stenosis, jejunal and ileal atresia, and malrotation and volvulus. The same methods were used to compare radiography and contrast enema in the detection of lower GI tract obstruction such as meconium plug syndrome, meconium ileus, Hirschsprung disease, and imperforate anus. Retrieved articles were appraised and assigned a level of evidence based on the Oxford University Centre for Evidence-Based Medicine hierarchy of validity for diagnostic studies. RESULTS: There were no sensitivities/specificities available for the imaging diagnosis of duodenal atresia or stenosis, jejunal or ileal atresias, meconium plug, and meconium ileus or for the use of cross-table lateral radiography for the diagnosis of rectal pouch distance from skin in imperforate anus. The retrieved sensitivity for the detection of malrotation on upper GI contrast study is 96%, and the sensitivity for the diagnosis of midgut volvulus on upper GI contrast study is 79%. The retrieved sensitivity and specificity for the detection of malrotation with volvulus on ultrasound were 89% and 92%, respectively. The retrieved sensitivity and specificity for the detection of Hirschsprung disease on contrast enema were 70% and 83%, respectively. The retrieved sensitivity of invertogram for the diagnosis of rectal pouch distance from skin in imperforate anus is 27%. The retrieved sensitivities of perineal ultrasound and colostography for the diagnosis of rectal pouch distance from skin in imperforate anus were 86% and 100%, respectively. CONCLUSIONS: There is limited evidence for the imaging diagnosis of duodenal atresia and stenosis, jejunal and ileal atresias, meconium plug, meconium ileus, and imperforate anus, with recommended practice based mainly on low-quality evidence or expert opinion. The available evidence supports the use of upper GI contrast study for the diagnosis of malrotation and volvulus, with ultrasound as an adjunct to diagnosis. Contrast enema is useful in the investigation of suspected Hirschsprung disease, but a negative study does not outrule the condition. Colostography is the investigation of choice for the work-up of infants with complex anorectal malformations before definitive surgical repair.

Spatial patterns and recruitment processes of coral assemblages among contrasting environmental conditions in the southwestern lagoon of New Caledonia.

We investigated the spatial distribution of adult and juvenile coral assemblages in the southwestern lagoon of New Caledonia, from disturbed fringing reefs within bays, to oceanic barrier reefs. Generic richness, abundance, and percent cover were highly variable at this scale, but no clear cross-shelf gradient was found. Rather, community composition was more related to reef biotopes. Correlations and canonical correspondence analyses revealed that composition and abundance of coral assemblages were related to substrate types (cover of turf algae and cover of encrusting coralline algae), but not to water quality or metal concentrations in sediments. We found a strong relationship between juvenile and adult distribution for all dominant genera, which suggests that recruitment processes are also a major factor structuring these populations. The densities of juveniles and their proportion in the coral assemblages were relatively low, which implies that replenishment capacities and potential for recovery are probably limited for these reefs.

First Report of Black Root Rot Caused by Thielaviopsis basicola on Soybean (Glycine max) in Arkansas.

Thielaviopsis basicola (Berk. & Broome) Ferraris (synonym Chalara elegans Nag Raj & Kendrick) is a soilborne plant-pathogenic fungus reported in many parts of the world. In Arkansas, T. basicola is found commonly in cotton fields (4). This fungus colonizes cortical tissue of seedlings under cool wet conditions, causing a dark brown or black discoloration of the roots and hypocotyls, resulting in stunted, slow-developing plants (4). In 2008, large areas of stunted soybean plants with shortened internodes were reported in a field in Phillips County, AR, where cotton had previously been produced. Soybean was planted in this field in early April when cool soil temperatures (~21 to 24°C) prevailed. Soybean plants at the v3 to v5 growth stages were observed to have extensive areas of black cortical root necrosis. Plant samples were collected and roots were excised, washed, and surface disinfested in a 10% NaOCl solution. Root segments were incubated on the carrot-based selective medium TB-CEN (3). T. basicola was isolated from incubated segments after 2 weeks at 21°C in the dark. Chlamydospore chains (44.8 to 56.0 × 8.4 to 11.2 µm) consisting of an average of six spores and endoconidia (8 to 30 × 3 to 5 µm) were observed with a compound microscope. In addition to plant tissue, soil was assayed and confirmed to be positive for T. basicola by the pour plate technique (3) with the medium TB-CEN. Greenhouse trials were conducted to confirm field observations. Soil from the Phillips County field was sterilized and reinfested with 100 CFU of chlaymdospore suspension per gram (dry weight) of soil. Fifty soybean seeds (cv. Schillinger 457) were planted in infested and sterilized soil and grown for 29 days. Results showed that 38% of plants germinated and survived in the T. basicola-infested soil compared with 71% in the sterile soil treatment. Fifteen of the nineteen plants that survived in the infested soil were positive for T. basicola, while all plants in the sterilized soil were negative for the fungus. Soybean has previously been reported to be a host of T. basicola worldwide, but North American reports have been confined to Canada and Michigan, where cool soil temperatures persist for longer periods during the early part of the growing season (1,2). To our knowledge, this is the first report of T. basicola being important in the growth of soybean in warmer latitudes where the pathogen has been observed frequently on cotton and tobacco. In areas where cotton has historically suffered seedling damage from T. basicola, black root rot may become important on soybean as production of the latter crop increases. Since the initial field observation and confirmation in 2008, multiple soybean fields in 10 Arkansas counties have been documented with black root rot, with an estimated 5 to 30% of plants in each field infected. References: (1) T. R. Anderson. Can. J. Plant Pathol. 6:71, 1984. (2) J. L. Lockwood et al. Plant Dis. Rep. 54:849, 1970. (3) L. P. Specht and G. J. Griffin. Can. J. Plant Pathol. 7:438, 1985. (4) N. R. Walker et al. Phytopathology 89:613, 1999.

Latent transforming growth factor beta1 activation in situ: quantitative and functional evidence after low-dose gamma-irradiation.

The biological activity of transforming growth factor beta1 (TGF-beta) is controlled by its secretion as a latent complex in which it is noncovalently associated with latency-associated peptide (LAP). Activation is the extracellular process in which TGF-beta is released from LAP, and is considered to be a primary regulatory control. We recently reported rapid and persistent changes in TGF-beta immunoreactivity in conjunction with extracellular matrix remodeling in gamma-irradiated mouse mammary gland. Our hypothesis is that these specific changes in immunoreactivity are indicative of latent TGF-beta activation. In the present study, we determined the radiation dose response and tested whether a functional relationship exists between radiation-induced TGF-beta and collagen type III remodeling. After radiation exposures as low as 0.1 Gy, we detected increased TGF-beta immunoreactivity in the mammary epithelium concomitant with decreased LAP immunostaining, which are events consistent with activation. Quantitative image analysis demonstrated a significant (P=0.0005) response at 0.1 Gy without an apparent threshold and a linear dose response to 5 Gy. However, in the adipose stroma, loss of LAP demonstrated a qualitative threshold at 0.5 Gy. Loss of LAP paralleled induction of collagen III immunoreactivity in this tissue compartment. We tested whether TGF-beta mediates collagen III expression by treating animals with TGF-beta panspecific monoclonal antibody, 1D11.16, administered i.p. shortly before irradiation. Radiation-induced collagen III staining in the adipose stroma was blocked in an antibody dose-dependent manner, which persisted through 7 days postirradiation. RNase protection assay revealed that radiation-induced elevation of total gland collagen III mRNA was also blocked by neutralizing antibody treatment. These data provide functional confirmation of the hypothesis that radiation exposure leads to latent TGF-beta activation, support our interpretation of the reciprocal shift in immunoreactivity as evidence of activation, and implicate TGF-beta as a mediator of tissue response to ionizing radiation. The sensitivity of activation to low radiation doses points to a potential role for TGF-beta in orchestrating tissue response to oxidative stress. As such, radiation may be useful as a probe to delineate the consequences of latent TGF-beta activation in situ.

p53 oncogene mutations in three human prostate cancer cell lines.

p53 gene structure and chromosome 17p alleles were studied in the three human prostate cancer cell lines, LNCaP, DU-145, and PC-3. Our laboratory has two separate culture lines of the LNCaP human prostate cancer cells. One strain, LNCaP-GW, had a mutation in one of two alleles at position 273 (arg > his). This mutation could not be detected in a second strain of LNCaP, LNCaP-ATCC. Immunohistochemical staining for P53 protein in the cell lines indicated that protein overexpression in LNCaP was heterogeneous, even in clonal isolates derived from LNCaP-GW that contained the codon 273 mutation in every cell. We also performed in vitro and in vivo growth analysis to compare the LNCaP-GW and LNCaP-ATCC cells. LNCaP-GW grew more rapidly than LNCaP-ATCC in vitro. However, LNCaP-ATCC formed tumors efficiently when inoculated into nude mice, whereas LNCaP-GW formed tumors much less efficiently. Consideration must be given to the notion that some of these p53 mutations arose during in vitro passage. We also confirmed published findings with two other human prostate cancer cell lines. In DU-145, two mutations were found in the p53 gene. A mutation at codon 274 (pro > leu) and a second mutation at codon 223 (val > phe) were present. PC-3 cells were hemizygous for chromosome 17p. The single copy of the p53 gene had a base pair deletion at codon 138 that generated a frame shift and a new in-frame stop codon at position 169.

Small membrane-associated GTP-binding proteins of catecholamine-secreting cells.

1. Four GTP-binding proteins (23-27 kDa) were identified in membranes from PC12 cells by [alpha 32P]GTP binding to nitrocellulose blots of SDS-polyacrylamide gels. 2. The GTP-binding proteins remained associated with membranes during stimulation of intact cells by K(+)-depolarization or even after addition of Ca2+ to digitonin-permeabilized cells. 3. By two-dimensional gel electrophoresis, six GTP-binding proteins were resolved and based on their mobility, their phosphorylation state appeared independent of Ca2+. 4. Fractionation of PC12 membranes showed that these GTP-binding proteins were broadly distributed in post-nuclear membranes with the plasma membranes containing the highest specific GTP-binding activity. 5. Membrane fractions from bovine adrenal medulla contain similar GTP-binding proteins with GTP-binding intensity also being highest in the plasma membrane. 6. The GTP-binding proteins could be concentrated in the detergent-rich fraction upon Triton X-114 phase separation.

Hydrolysis-resistant GTP analogs stimulate catecholamine release from digitonin-permeabilized PC12 cells.

The effect of the hydrolysis-resistant GTP analogs, guanosine 5'-O-(3-thiotriphosphate) (GTP gamma S) and guanylyl imidodiphosphate (GMPPNP), on norepinephrine (NE) secretion from digitonin-permeabilized rat pheochromocytoma cells, PC12, was examined. Although secretion in the presence of saturating Ca2+ (10 microM) was not affected by GTP gamma S or GMPPNP, secretion in the absence of Ca2+ was stimulated by these GTP analogs. Secretion induced by saturating concentrations of GTP gamma S or GMPPNP was approximately 80% of that induced by 10 microM Ca2+. Half-maximum stimulation was induced by 30 microM GTP gamma S or GMPPNP. Both Ca2(+)-stimulated and GTP gamma S-stimulated secretion were ATP dependent and inhibited by N-ethylmaleimide. The GTP gamma S-stimulated secretion of NE from permeabilized PC12 cells does not appear to result from either the release of Ca2+ or the activation of protein kinase C. Activation of protein kinase C by pretreatment of intact cells with 12-O-tetradecanoylphorbol 13-acetate caused a 50% increase in both Ca2(+)-stimulated and GTP gamma S-stimulated secretion. Cholera and pertussis toxins did not affect Ca2(+)-stimulated or GTP gamma S-stimulated NE secretion. Guanosine 5'-O-(2-thiodiphosphate) (GDP beta S) and GTP inhibited GTP gamma S-stimulated secretion but not Ca2(+)-stimulated secretion. The inability of GDP beta S to inhibit Ca2(+)-stimulated secretion indicates that the process affected by GTP gamma S is not an essential step in the Ca2(+)-stimulated pathway.

Protein kinase C phosphorylation of thymus myosin.

We have examined the effect of protein kinase C phosphorylation on the actin-activated ATPase activity and filament stability of calf thymus myosin. Protein kinase C phosphorylated thymus myosin regulatory light chains, LC20, on two sites which are different from the site phosphorylated by myosin light chain kinase. The light meromyosin part of the thymus myosin heavy chain was also phosphorylated by protein kinase C, but at a rate about 10% that of LC20. Under conditions where both unphosphorylated thymus and myosin light chain kinase-phosphorylated thymus myosin were filamentous and under conditions where myosin light chain kinase phosphorylation induces myosin filament formation, protein kinase C phosphorylation had little effect on the actin-activated ATPase activity or filament stability of unphosphorylated or myosin light chain kinase-phosphorylated myosin. In contrast, protein kinase C phosphorylation has been reported to inhibit the actin-activated ATPase activity of gizzard myosin.

Protein kinase C activity, protein phosphorylation and germinal vesicle breakdown in Spisula oocytes.

To test the possible role of protein kinase C (C-kinase) in regulating germinal vesicle breakdown (GVBD) in Spisula oocytes, we studied the effects of phorbol esters and antagonists of C-kinase on GVBD and protein phosphorylation. Responses to these agents were compared to those elicited by fertilization or increased extracellular K+. The tumor-promoting phorbol ester, 12-O-tetradecanoylphorbol-13-acetate (TPA), a potent agonist of C-kinase, elicited GVBD with half-maximal stimulation at 20 nM. By contrast, 4 alpha-phorbol-12,13-didecanoate, a phorbol ester which does not stimulate C-kinase, did not trigger GVBD. TPA accelerated GVBD when induced by excess K+, but it did not affect the time course of the process when initiated by fertilization. Three structurally different antagonists of C-kinase (W-7, H-7, and retinol) all blocked GVBD when induced by fertilization or TPA. When oocytes were preincubated with [32P]orthophosphate and then stimulated to undergo GVBD by fertilization, TPA, or 45 mM K+, protein phosphorylation was greatly increased, especially for a polypeptide(s) of about 45 kDa. Phosphorylation increased prior to GVBD. Retinol inhibited phosphorylation in activated eggs. C-kinase activity was demonstrated in oocyte extracts. These results strongly suggest that protein phosphorylation by C-kinase is involved in the pathway that regulates GVBD in Spisula oocytes.

An automated assay for adenylate cyclase using reversed-phase high-performance liquid chromatography.

An automated high-performance liquid chromatographic method for the assay of 3',5'-cyclic AMP was developed using octylsilica. Total analysis time was 10.1 min, with cAMP eluting at 3 min. As little as 10 pmol of cyclic AMP could be detected by absorption at 260 nm. Peak height and area were linearly related to cyclic AMP concentration over at least two orders of magnitude. The analytical procedure gave good results in the assay of crude microsomal preparations of adenylate cyclase from both bovine brain and sea urchin eggs. The method was used to demonstrate that sea urchin adenylate cyclase is a Ca2+-activated enzyme.

Reproductive and leptospiral studies on beef cattle in central Queensland.

The effect of rainfall on reproductive performance in beef cattle and the effects of rainfall and soil type on the prevalence of leptospirosis in beef cattle in inland central Queensland are described. Low annual rainfall produced a significant (P less than 0.05) decrease in calf branding rates. Leptospirosis (due to serovar hardjo) was serologically more prevalent after rain and on farms with high water holding capacity soils but there was no significant difference in branding rates between cattle on high or low water holding capacity soils. As a secondary mid-year rainfall peak is a feature of the area, leptospirosis due to serovar hardjo will tend to spread when most of the breeding herd is in the last trimester of pregnancy. The prevalence of leptospirosis due to serovar pomona is significantly lower in the region.

Possible involvement of calmodulin in maturation and activation of Chaetopterus eggs.

We report the isolation of calmodulin from oocytes of Chaetopterus pergamentaceus. The identification of this protein is based on (1) activation of beef heart cAMP phosphodiesterase, (2) heat stability, (3) sensitivity to chlorpromazine, and (4) electrophoretic mobility identical to that of porcine brain calmodulin after sodium dodecyl sulfate-polyacrylamide gel electrophoresis in the presence of either Ca2+ or EGTA. We treated oocytes with chlorpromazine and W-7 to investigate the involvement of calmodulin in meiosis initiation and egg activation. Very low concentrations of chlorpromazine inhibited germinal vesicle breakdown (GVBD). This effect was shown to be dependent upon bright indirect light, since the drug was much less effective at GVBD inhibition under conditions of very low illumination. Higher concentrations of chlorpromazine and W-7 (100 microM) inhibited GVBD and activated eggs with intact germinal vesicles as determined by fertilization envelope formation and the onset of ameboid activity. Neither egg activation nor inhibition of calmodulin stimulation of phosphodiesterase activity in vitro was affected by light. These results are consistent with a role for calmodulin in egg activation and GVBD, but suggest that chlorpromazine in bright light may prevent GVBD by some mechanism other than calmodulin inhibition.

Sequestered calcium triggers oocyte maturation in Chaetopterus.

In order to test the involvement of Ca2+ in maturation and activation of eggs, we have treated Chaetopterus eggs with ionophore A23187 and quercetin, an inhibitor of Ca2+-dependent ATPase. Ionophore A23187 induced rapid germinal vesicle breakdown (GVBD) and activated eggs as evidence by fertilization envelope elevation at a wide range of concentrations. Higher concentrations of A23187 induced GVBD in Ca2+-free artificial sea water, demonstrating the independence of GVBD in Chaetopterus from external Ca2+. At high concentrations of ionophore, eggs became ameboid and underwent the initial phases of differentiation without cleavage. Low concentrations of quercetin induced GVBD with or without external CA2+. This treatment did not activate eggs, but allowed them to be fertilized and undergo some development. The results of these experiments indicate 1) that Ca2+ fluxes regulate GVBD and activation in Chaetopterus, 2) that these fluxes can be internally generated, and 3) that Ca2+ sequestration by Ca2+-dependent ATPase may have a role in maintaining the intact germinal vesicle.

Effects of postovulatory aging on leucine uptake and incorporation in mouse eggs. A brief note.

In order to delineate biochemical alterations during gamete senescence leucine uptake and incorporation in aging mouse eggs were investigated. One hour after ovulation eggs were removed from the oviducts and labeled (unaged) or incubated for 24 hours before labeling (in vitro aged) with [3H]leucine. In vivo aged eggs were removed from the oviducts 25 hours after ovulation and incubated in medium containing [3H]leucine. Aging of eggs for 24 hours resulted in a significant increase in the accumulation of [3H]leucine. The observed increase was larger in ova aged in vitro than in vivo, indicating that culture conditions affect leucine accumulation. Comparison of in vitro aged and unaged eggs revealed no significant difference in net leucine incorporation in to acid-insoluble material. In addition to previously documented morphological alterations, the data presented herein describe some of the biochemical changes that accompany aging of the mouse ovum. These results are discussed in light of theories of aging proposed for somatic cells.