Correlation between CT-estimated tumor volume, pathologic tumor volume, and final pathologic specimen weight in children with Wilms' tumor

OBJECTIVE

To evaluate the relationship of Wilms' tumor (WT) volume to weight, and evaluate computed tomography (CT) scan-derived final pathologic specimen weight estimation models.

METHODS

We retrospectively reviewed WT patients from 2003 to 2011 who had a pre-operative CT scan, final pathologic specimen weight, and tumor dimensions. A partial nephrectomy tumor cohort (n = 12) was used derive WT density. A radical nephrectomy cohort (n = 45) was used to develop a simplified estimation equation of final pathologic specimen weight, and analysis of all known estimation models was performed.

RESULTS

Fifty-two patients were identified. WT volume and weight were not equivalent (p = 0.0410). WT density was 1.3091 g/cm(3). WT volume and final pathologic specimen weight were not significant (p = 0.0007). Our model (p = 0.9983) and CT estimated ellipsoidal volume (p = 0.0741) were able to estimate final pathologic specimen weight in all tumors. However, CT-estimated ellipsoidal volume failed to estimate final pathologic specimen weight in specimens < 250 g (p = 0.0066).

CONCLUSION

Pathologic WT volume is not equivalent to final pathologic specimen weight. Final pathologic specimen weight can be estimated from a pre-operative CT scan, which suggests that it may be used to improve pre-operative surgical planning and to reduce treatment morbidity.

Asymptotic and numerical analysis of electrohydrodynamic flows of dielectric liquid

We perform an asymptotic analysis of electrohydrodynamic (EHD) flow of nonpolar liquid subjected to an external, nonuniform electric field. The domain of interest covers the bulk as well as the thin dissociation layers (DSLs) near the electrodes. Outer (i.e., bulk) equations for the ion transport in hierarchical order of perturbation parameters can be expressed in linear form, whereas the inner (i.e., DSL) equations take a nonlinear form. We derive a simple formula in terms of various parameters which can be used to estimate the relative importance of the DSL-driven flow compared with the bulk-driven flow. EHD flow over a pair of cylindrical electrodes is then solved asymptotically and numerically. It is found that in large geometric scale and high ion concentration the EHD flow is dominated by the bulk-charge-induced flow. As the scale and concentration are decreased, the DSL-driven slip velocity increases and the resultant flow tends to dominate the domain and finally leads to flow reversal. We also conduct a flow-visualization experiment to verify the analysis and attain good agreement between the two results with parameter tuning. We finally show, based on the comparison of experimental and numerical solutions, that the rate of free-ion generation (dissociation) should be less than the one predicted from the existing formula.

The post-synaptic density of human postmortem brain tissues: an experimental study paradigm for neuropsychiatric illnesses

Recent molecular genetics studies have suggested various trans-synaptic processes for pathophysiologic mechanisms of neuropsychiatric illnesses. Examination of pre- and post-synaptic scaffolds in the brains of patients would greatly aid further investigation, yet such an approach in human postmortem tissue has yet to be tested. We have examined three methods using density gradient based purification of synaptosomes followed by detergent extraction (Method 1) and the pH based differential extraction of synaptic membranes (Methods 2 and 3). All three methods separated fractions from human postmortem brains that were highly enriched in typical PSD proteins, almost to the exclusion of pre-synaptic proteins. We examined these fractions using electron microscopy (EM) and verified the integrity of the synaptic membrane and PSD fractions derived from human postmortem brain tissues. We analyzed protein composition of the PSD fractions using two dimensional liquid chromatography tandem mass spectrometry (2D LC-MS/MS) and observed known PSD proteins by mass spectrometry. Immunoprecipitation and immunoblot studies revealed that expected protein-protein interactions and certain posttranscriptional modulations were maintained in PSD fractions. Our results demonstrate that PSD fractions can be isolated from human postmortem brain tissues with a reasonable degree of integrity. This approach may foster novel postmortem brain research paradigms in which the stoichiometry and protein composition of specific microdomains are examined.

Dysbindin-1 is a synaptic and microtubular protein that binds brain snapin

Variations in the gene encoding the novel protein dysbindin-1 (DTNBP1) are among the most commonly reported genetic variations associated with schizophrenia. Recent studies show that those variations are also associated with cognitive functioning in carriers with and without psychiatric diagnoses, suggesting a general role for dysbindin-1 in cognition. Such a role could stem from the protein's known ability to affect neuronal glutamate release. How dysbindin-1 might affect glutamate release nevertheless remains unknown without the discovery of the protein's neuronal binding partners and its subcellular locus of action. We demonstrate here that snapin is a binding partner of dysbindin-1 in vitro and in the brain. Tissue fractionation of whole mouse brains and human hippocampal formations revealed that both dysbindin-1 and snapin are concentrated in tissue enriched in synaptic vesicle membranes and less commonly in postsynaptic densities. It is not detected in presynaptic tissue fractions lacking synaptic vesicles. Consistent with that finding, immunoelectron microscopy showed that dysbindin-1 is located in (i) synaptic vesicles of axospinous terminals in the dentate gyrus inner molecular layer and CA1 stratum radiatum and in (ii) postsynaptic densities and microtubules of dentate hilus neurons and CA1 pyramidal cells. The labeled synapses are often asymmetric with thick postsynaptic densities suggestive of glutamatergic synapses, which are likely to be derived from dentate mossy cells and CA3 pyramidal cells. The function of dysbindin-1 in presynaptic, postsynaptic and microtubule locations may all be related to known functions of snapin.

Altered neuregulin 1-erbB4 signaling contributes to NMDA receptor hypofunction in schizophrenia

Recent molecular genetics studies implicate neuregulin 1 (NRG1) and its receptor erbB in the pathophysiology of schizophrenia. Among NRG1 receptors, erbB4 is of particular interest because of its crucial roles in neurodevelopment and in the modulation of N-methyl-D-aspartate (NMDA) receptor signaling. Here, using a new postmortem tissue-stimulation approach, we show a marked increase in NRG1-induced activation of erbB4 in the prefrontal cortex in schizophrenia. Levels of NRG1 and erbB4, however, did not differ between schizophrenia and control groups. To evaluate possible causes for this hyperactivation of erbB4 signaling, we examined the association of erbB4 with PSD-95 (postsynaptic density protein of 95 kDa), as this association has been shown to facilitate activation of erbB4. Schizophrenia subjects showed substantial increases in erbB4-PSD-95 interactions. We found that NRG1 stimulation suppresses NMDA receptor activation in the human prefrontal cortex, as previously reported in the rodent cortex. NRG1-induced suppression of NMDA receptor activation was more pronounced in schizophrenia subjects than in controls, consistent with enhanced NRG1-erbB4 signaling seen in this illness. Therefore, these findings suggest that enhanced NRG1 signaling may contribute to NMDA hypofunction in schizophrenia.

Mechanisms of pathogenicity of influenza A (H5N1) viruses in mice

Avian-like H5N1 influenza viruses isolated from humans in 1997 were shown to have two distinct pathogenic phenotypes in BALB/c mice, after intranasal inoculation and without prior adaptation to this host. To further understand the mechanisms of H5N1 pathogenicity, we investigated the consequences of the mute of viral inoculation on morbidity and mortality, viral replication in pulmonary and systemic organs, and lymphocyte depletion. This study demonstrates the importance of extrapulmonary spread and replication, particularly in the brain, for the lethality of H5N1 viruses.

Neurological manifestations of avian influenza viruses in mammals

The H5N1 viruses isolated from humans in Hong Kong directly infected both mice and ferrets without prior adaptation to either host. Two representative viruses, A/Hong Kong/483/97 (HK/483) and A/Hong Kong/486/97 (HK/486) were equally virulent in outbred ferrets but differed in their virulence in inbred mice. Both HK/483 and HK/486 replicated systemically in ferrets and showed neurologic manifestations. In contrast, intranasal infection of mice with HK/483, but not HK/486, resulted in viral spread to the brain, neurologic signs, and death. However, HK/486 was able to replicate in the brain and induce lethal disease following direct intracerebral inoculation.

RNA editing activity is associated with splicing factors in lnRNP particles: The nuclear pre-mRNA processing machinery

Multiple members of the ADAR (adenosine deaminases acting on RNA) gene family are involved in A-to-I RNA editing. It has been speculated that they may form a large multicomponent protein complex. Possible candidates for such complexes are large nuclear ribonucleoprotein (lnRNP) particles. The lnRNP particles consist mainly of four spliceosomal subunits that assemble together with the pre-mRNA to form a large particle and thus are viewed as the naturally assembled pre-mRNA processing machinery. Here we investigated the presence of ADARs in lnRNP particles by Western blot analysis using anti-ADAR antibodies and by indirect immunoprecipitation. Both ADAR1 and ADAR2 were found associated with the spliceosomal components Sm and SR proteins within the lnRNP particles. The two ADARs, associated with lnRNP particles, were enzymatically active in site-selective A-to-I RNA editing. We demonstrate the association of ADAR RNA editing enzymes with physiological supramolecular complexes, the lnRNP particles.

IL-13-induced airway hyperreactivity during respiratory syncytial virus infection is STAT6 dependent

Airway damage and hyperreactivity induced during respiratory syncytial virus (RSV) infection can have a prolonged effect in infants and young children. These infections can alter the long-term function of the lung and may lead to severe asthma-like responses. In these studies, the role of IL-13 in inducing and maintaining a prolonged airway hyperreactivity response was examined using a mouse model of primary RSV infection. Using this model, there was evidence of significant airway epithelial cell damage and sloughing, along with mucus production. The airway hyperreactivity response was significantly increased by 8 days postinfection, peaked during days 10-12, and began to resolve by day 14. When the local production of Th1- and Th2-associated cytokines was examined, there was a significant increase, primarily in IL-13, as the viral response progressed. Treatment of RSV-infected mice with anti-IL-13 substantially inhibited airway hyperreactivity. Anti-IL-4 treatment had no effect on the RSV-induced responses. Interestingly, when IL-13 was neutralized, an early increase in IL-12 production was observed within the lungs, as was a significantly lower level of viral Ags, suggesting that IL-13 may be regulating an important antiviral pathway. The examination of RSV-induced airway hyperreactivity in STAT6(-/-) mice demonstrated a significant attenuation of the response, similar to the anti-IL-13 treatment. In addition, STAT6(-/-) mice had a significant alteration of mucus-producing cells in the airway. Altogether, these studies suggest that a primary factor leading to chronic RSV-induced airway dysfunction may be the inappropriate production of IL-13.

A third member of the RNA-specific adenosine deaminase gene family, ADAR3, contains both single- and double-stranded RNA binding domains

Members of the double-stranded RNA- (dsRNA) specific adenosine deaminase gene family convert adenosine residues into inosines in dsRNA and are involved in A-to-I RNA editing of transcripts of glutamate receptor (GluR) subunits and serotonin receptor subtype 2C (5-HT(2C)R). We have isolated hADAR3, the third member of this class of human enzyme and investigated its editing site selectivity using in vitro RNA editing assay systems. As originally reported for rat ADAR3 or RED2, purified ADAR3 proteins could not edit GluR-B RNA at the "Q/R" site, the "R/G" site, and the intronic "hot spot" site. In addition, ADAR3 did not edit any of five sites discovered recently within the intracellular loop II region of 5-HT(2C)R RNAs, confirming its total lack of editing activity for currently known substrate RNAs. Filter-binding analyses revealed that ADAR3 is capable of binding not only to dsRNA but also to single-stranded RNA (ssRNA). Deletion mutagenesis identified a region rich in arginine residues located in the N-terminus that is responsible for binding of ADAR3 to ssRNA. The presence of this ssRNA-binding domain as well as its expression in restricted brain regions and postmitotic neurons make ADAR3 distinct from the other two ADAR gene family members, editing competent ADAR1 and ADAR2. ADAR3 inhibited in vitro the activities of RNA editing enzymes of the ADAR gene family, raising the possibility of a regulatory role in RNA editing.

Altered G protein-coupling functions of RNA editing isoform and splicing variant serotonin2C receptors

Different isoforms of serotonin subtype 2C receptor (5-HT(2C)R) with altered G protein-coupling efficacy are generated by RNA editing, which converts genomically encoded adenosine residues into inosines. In combination, editing of five sites all located within the second intracellular loop region of 5-HT(2C)R mRNA changes the gene-encoded Ile, Asn, and Ile at positions 156, 158, and 160, respectively. We analyzed the G protein-coupling functions of previously unreported editing isoform receptors. An approximately 13-fold reduction in the agonist potency for G protein-coupling stimulation as well as a significantly reduced basal level activity was observed with the thalamus-specific isoform carrying Ile156, Gly158, and Val160 (5-HT(2C)R-IGV). In contrast, the agonist was four- to five-fold less potent with 5-HT(2C)R-MSV and -IDV, detected in the amygdala and choroid plexus, respectively, indicating a dominant role for the amino acid residue at position 158 in receptor functions. We also identified a splicing variant receptor with a truncated C terminus that displayed no ligand binding capacity or G protein-coupling activity. Examination of the alternatively spliced RNA encoding this truncated receptor suggests that editing of this variant RNA occurs after completion of splicing, resulting in complete editing at all five sites.

Alterations of p53 gene in primary gastric cancer tissues

This study was conducted to investigate the p53 gene alterations in 25 surgically-resected gastric adenocarcinomas in the Korea Cancer Center Hospital by polymerase chain reaction single-strand conformation polymorphism analysis (PCR-SSCP) for exons 4-8 and immunohistochemical staining (IHCS) with anti-p53 antibody, DO-7. p53 mutations were detected in nine (36%) out of 25 cancer tissues by PCR-SSCP in exon 4-8: 0,1,1,6 and 1 mutations in exons 4,5,6,7 and 8, respectively. All tissues were also tested by IHCS, and positive staining was observed in 11 cases (44%). A discrepancy of the results between the two methods was observed in four cases. In one which showed positivity by PCR-SSCP a negative reaction by IHCS, the two base deletion was observed in exon 7. On the other hand, in three cases the mutation was detected only in IHCS but not in PCR-SSCP. The exact mechanism by which this discrepancy develops is not clear at present, although it may be due to the mutation of other exons not tested in this study or the relatively low sensitivity of the PCR-SSCP method. The incidence of p53 gene mutations was analysed according to pathologic stage and histological differentiation, but no significant difference was observed between the p53 alterations and these factors. By combined use of PCR-SSCP and IHCS, 48% of the 25 primary gastric cancer were considered to have mutations of the p53 gene. These results suggest that p53 mutation is not an infrequent event in primary gastric cancer and the p53 gene plays an important role in the carcinogenesis process of gastric cancer.

Deletion of a single-copy tRNA affects microtubule function in Saccharomyces cerevisiae

rts1-1 was identified as an extragenic suppressor of tub2-104, a cold-sensitive allele of the sole gene encoding beta-tubulin in the yeast, Saccharomyces cerevisiae. In addition, rts1-1 cells are heat sensitive and resistant to the microtubule-destabilizing drug, benomyl. The rts1-1 mutation is a deletion of approximately 5 kb of genomic DNA on chromosome X that includes one open reading frame and three tRNA genes. Dissection of this region shows that heat sensitivity is due to deletion of the open reading frame (HIT1). Suppression and benomyl resistance are caused by deletion of the gene encoding a tRNA(Arg)AGG (HSX1). Northern analysis of rts1-1 cells indicates that HSX1 is the only gene encoding this tRNA. Deletion of HSX1 does not suppress the tub2-104 mutation by misreading at the AGG codons in TUB2. It also does not suppress by interfering with the protein arginylation that targets certain proteins for degradation. These results leave open the prospect that this tRNA(Arg)AGG plays a novel role in the cell.

Dosimetry and biodistribution of an iodine-123-labeled somatostatin analog in patients with neuroendocrine tumors

A modified method for the preparation of a radiolabeled analog of somatostatin (123I-octreotide) is described. The pharmacokinetics and dosimetry of this analog were evaluated in patients with neuroendocrine tumors. Thirty patients had multiple blood and urine samples and sequential anterior and posterior whole-body scintigraphy up to 40 hr postinjection of 123I-octreotide. Region of interest analysis of the whole-body images was used to determine organ and tumor doses. The 123I-octreotide was rapidly cleared from the blood with a T 1/2 of 10 min by the hepatobiliary system. By 40 hr, approximately 55% was eliminated in the feces. The gallbladder wall received the highest dose (0.48 rad/mCi), with other organs receiving doses of 0.12 rad/mCi or less. Tumors were identified in 25 of 28 satisfactory studies. Tumor doses ranged from 0.1 to 0.6 rad/mCi. Calculations with 131I instead of 123I indicated that the gallbladder wall would receive 2 rad/mCi, while average tumor doses would range from 0.9 to 5.0 rad/mCi. Iodine-123-octreotide is a useful agent for the visualization of neuroendocrine tumors. The rapid washout of this agent from tumors precludes the possibility of radiotherapy with 131I-octreotide in these patients.

Rapid radiotracer washout from the heart: effect on image quality in SPECT performed with a single-headed gamma camera system

Technetium-99m-teboroxime demonstrates high extraction and rapid washout from the myocardium. To evaluate the feasibility of performing SPECT with this agent using a single-headed gamma camera system, a series of phantom studies were performed that simulated varying degrees of washout from normal and "ischemic" regions of the myocardium. In the absence of ischemic regions, short axis profiles were relatively unaffected by washout of less than 50% of activity over the duration of a SPECT acquisition. However, significant corruption of the SPECT data was observed when large (greater than a factor of 2) differences existed in the washout of activity from normal and "ischemic" myocardium. This corruption was observed with 30%-40% washout of activity from normal regions of the heart. Based on published washout rates, these results indicate that clinical studies with 99mTc-teboroxime may need to be completed within 2-4 min to order to prevent degradation of image quality due to differential washout effects.

Essential activation of Na(+)-H+ exchange by [H+]i in HL-60 cells

The intracellular pH (pHi) dependence of the rate of Na(+)-H+ exchange was determined in undifferentiated promyelocytic HL-60 cells by measuring alkalinization rates using the fluorescent pHi indicator 2',7'-bis(2-carboxyethyl)-5,6-carboxyfluorescein (BCECF). BCECF was calibrated in the pH range from 5 to 7 using the nigericin technique of Thomas and co-workers (J. A. Thomas, R. N. Buchsbaum, A. Zimniak, and E. Racker. Biochemistry 18: 2210-2218, 1979). Exchange rate increases as pHi is lowered below pH 7.00. At low pH (pH below 6.3), the dependence of Na(+)-H+ exchange rate on intracellular proton activity is well fitted by the Michaelis-Menten equation with a maximum exchange velocity of 33.7 +/- 2.4 mmol H(+).1 cell water-1.min-1 and a half-saturation constant of 1.35 +/- 0.28 microM (corresponding to a minus log of the Michaelis constant of 5.89). However, a Hill plot reveals that the Hill coefficient changes gradually from one to two when pH is changed from 5 to 7, ruling out Michaelian kinetics. The dependence of exchange flux on internal protons is well fit in the full pH range from 5 to 7 by a simple kinetic model (essential activation) with modifier and transport sites for internal proton binding. At low pH, failure to correct BCECF measurement of pHi for contribution to fluorescence signal from extracellular dye and for quenching of intracellular BCECF leads to an artifactual increase in the measured Hill coefficient. These two findings (increase in Hill coefficient as pHi is increased and artifactual increase in Hill coefficient because of methodological reasons) provide a good explanation for the wide range of Hill coefficients reported in the literature.

Two functional psbD genes in the cyanobacterium Synechococcus sp. strain PCC 7942

The cyanobacterium Synechococcus sp. strain PCC 7942 has two copies of the psbD gene which encodes the D2 polypeptide of the photosystem II (PSII) reaction center. One of the genes, psbDI, overlaps the open reading frame of another photosystem II gene, psbC; the psbDII gene is monocistronic. Gene inactivation experiments had previously shown that psbDII is dispensable under normal laboratory growth conditions. However, similar experiments with psbDI never produced viable psbDI-inactivated mutants, presumably because psbC expression depends on transcription through psbDI. The experiments described here were designed to assess the need for psbDI independent of the need for expression of psbC. A strain, AMC027, was engineered in which a second copy of psbC was expressed from the psbDII locus. Northern (RNA) blot analysis confirmed that both psbDI and psbDII gave rise to dicistronic messages containing psbC sequences in AMC027. In this genetic background, it was possible to inactivate psbDI, creating strain AMC050 and indicating that the psbDII gene is functional. Western immunoblot analysis showed that the products of psbD and psbC, the PSII proteins D2 and CP43, respectively, were present in thylakoids of AMC050, but at reduced levels relative to the wild type, the mutant AMC027, and two psbDII-inactivated mutants. AMC050 consistently formed small colonies on plates and competed poorly in mixed-culture experiments. This suggested that, although not essential for viability, expression from the psbDI locus is required to produce sufficient D2 and CP43 for optimal growth.

The electrodiagnosis of the carpal tunnel syndrome

The carpal tunnel syndrome is one of the most commonly discussed subjects among the public, as well as the medical community, these days. Even though this is a rather simple nerve compression, which can be easily corrected, the carpal tunnel syndrome can induce further complications, sometimes leading to total disability of the patient. Early, proper diagnosis and treatment is very vital. Unfortunately, the exact pathomechanism and proper diagnosis is yet to be seen. As electromyographers, the authors would like to re-visit this debatable carpal tunnel syndrome emphasizing the electrodiagnosis. Among the electrodiagnostic tests, comparison of distal motor or sensory latency of the median nerve to the ulnar nerve along with amplitude of the response, was found to be the most sensitive test. Also, the C6 cervical radiculopathy and the pronator syndrome can present similar clinical pictures and require a differentiation. After successful surgery many patients still complain of subjective residual symptoms. The electrophysiologic findings do not correspond to the clinical progress in many cases. The authors also experienced that most of the victims, following successful surgery, still would benefit from a proper exercise program including instruction for proper body mechanics before they return to their previous activities, to lessen the undesirable complications including the reflex sympathetic dystrophy.

Genetic relationship of two highly studied Synechococcus strains designated Anacystis nidulans

The cyanobacteria Synechococcus sp. strain PCC 7942 and Synechococcus sp. strain PCC 6301 are very closely related and both have been designated by the binomial Anacystis nidulans. The only established difference between the two strains is the superior transformation properties of strain PCC 7942. Significant homology between the rRNA genes of these strains was demonstrated by the ability of an rRNA operon from strain PCC 6301, interrupted by a spectinomycin and streptomycin resistance marker, to transform strain PCC 7942 by recombining with and replacing an endogenous rRNA operon. Restriction fragment length polymorphism data indicated that the chromosomes of the two strains were conserved around the three psbA loci, the two rRNA operons, and the psbDI locus. However, multiple polymorphisms were detected downstream of the psbDII locus, identifying a DNA rearrangement such as an inversion, insertion, or deletion within the chromosome. Analysis of genome structure by pulsed-field gel electrophoresis of large NotI restriction fragments showed only two bands that were visibly shifted between the chromosomes of the two strains. These data support their very close genetic relationship and the feasibility of studying genes derived from strain PCC 6301 in the highly transformable PCC 7942 strain.

Effects of taurodeoxycholate on in vivo water and solute transport in rat jejunum in absence and presence of calcium

Bile acids and fatty acids enhance the permeability of brush-border membrane vesicles for calcium. It has been postulated that increased influx of calcium into the enterocyte might be responsible for the fluid secretion induced by dihydroxy bile acids and fatty acids. During in vivo perfusion studies of the rat jejunum, 15 mM taurodeoxycholate induced secretion of electrolytes and water (P less than 0.001), reduced glucose absorption (P less than 0.001), and enhanced the absorption of mannitol (P less than 0.0125) and calcium (P less than 0.001). Calcium absorption continued to be enhanced during perfusion of a CaCl2-containing solution following the perfusion with taurodeoxycholate (P less than 0.05). In view of the previously demonstrated enhanced permeability of the apical brush-border membrane in the presence of bile acids, it is very likely that some calcium enters the enterocyte along the steep concentration gradient in the presence of taurodeoxycholate. In spite of enhanced calcium absorption, 15 mM CaCl2 had no effect on control absorption rates or on fluid secretion induced by taurodeoxycholate. The data indicate that the effects of bile acids on intestinal transport are not mediated by an influx of calcium into the enterocyte.