A novel toxin-antitoxin system swpAB alters gene expression patterns and reduces virulence expression in enterohemorrhagic Escherichia coli

Toxin-antitoxin (TA) systems are found widely among many bacteria, including enterohemorrhagic Escherichia coli (EHEC), but their functions are still poorly understood. In this study, we identified and characterized a novel TA system belonging to the relBE family, classified as a type II TA system, found in EHEC. The protein encoded by the toxin gene is homologous to RelE ribonuclease. Using various conditions for increasing the toxin activity, high-level induction of a toxin gene, and repression of an antitoxin gene in wild-type EHEC, we showed that the TA system, named swpAB (switching of gene expression profile), is involved in selective repression of a set of genes, including some virulence genes, and in the reduction of adherence capacity, rather than in suppression of bacterial growth. A detailed analysis of the profiles of RNA levels along sequences at 15 min after high expression of swpA revealed that two virulence genes, espA and tir, were direct targets of the SwpA toxin. These results suggested that the swpAB system can alter gene expression patterns and change bacterial physiological activity without affecting bacterial growth.

SlyA regulates virulence gene expressions through activation of pchA regulatory gene in enterohemorrhagic Escherichia coli

SlyA is a DNA-binding protein that alters the nucleoid complex composed of histone-like nucleoid-structuring protein (H-NS) and activates gene expression. In enterohemorrhagic Escherichia coli (EHEC), the expression of virulence genes is repressed by H-NS but is upregulated in response to environmental factors by releasing a nucleoid complex. In this study, we examined the effect of slyA deletion mutation in EHEC and discovered that the production of LEE (locus of enterocyte effacement)-encoded EspB and Tir, as well as cell adherence ability, was reduced in the mutant compared to wild type. The promoter activity of the LEE1 operon, including the regulatory gene, ler, was reduced by slyA mutation, but tac promoter-controlled expression of pchA, which is a regulatory gene of LEE1, abolished the effect. The promoter activity of pchA was downregulated by the slyA mutation. Furthermore, the coding region was required for its regulation and was bound to SlyA, which indicates the direct regulation of pchA by SlyA. However, the slyA mutation did not affect the butyrate-induced increase in pchA promoter activity. Additionally, pchA promoter activity was increased via induction of lrp, a regulatory gene for butyrate response, in the slyA mutant and, conversely, by introducing high copies of slyA into the lrp mutant. These results indicate that SlyA is a positive regulator of pchA and is independent of the Lrp regulatory system. SlyA may be involved in virulence expression in EHEC, maintaining a certain level of expression in the absence of butyrate response. This article is protected by copyright. All rights reserved.

Global Guidelines in Dermatology Mapping Project (GUIDEMAP): a scoping review of dermatology clinical practice guidelines

BACKGROUND

Clinical practice guidelines (CPGs) play a critical role in standardizing and improving treatment outcomes based on the available evidence. It is unclear how many CPGs are available globally to assist clinicians in the management of patients with skin disease.

OBJECTIVES

To search for and identify CPGs for dermatological conditions with the highest burden globally.

METHODS

We adapted a list of 12 dermatological conditions with the highest burden from the Global Burden of Disease (GBD) study 2019. A systematic literature search was done to identify CPGs published between October 2014 to October 2019. The scoping review was conducted and reported in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) framework.

RESULTS

A total of 226 CPGs were included. Melanoma had the greatest representation in the CPGs, followed by dermatitis and psoriasis. Skin cancers had a relatively high CPG representation but with lower GBD disease burden ranking. There was an uneven distribution by geographical region, with resource-poor settings being under-represented. The skin disease categories of the CPGs correlated weakly with the GBD disability-adjusted life-years metrics. Eighty-nine CPGs did not have funding disclosures and 34 CPGs were behind a paywall.

CONCLUSIONS

The global production of dermatology CPGs showed wide variation in geographical representation, article accessibility and reporting of funding. The number of skin disease CPGs were not commensurate with its disease burden. Future work will critically appraise the methodology and quality of dermatology CPGs and lead to the production of an accessible online resource summarizing these findings.

Enterohaemorrhagic Escherichia coli activates nitrate respiration to benefit from the inflammatory response for initiation of microcolony-formation

Background

For successful colonization, enterohaemorrhagic Escherichia coli (EHEC) injects virulence factors, called effectors, into target cells through the type three secretion system (T3SS), which is composed of a needle and basal body. Under anaerobic conditions, the T3SS machinery remains immature and does not have a needle structure. However, activation of nitrate respiration enhances the completion of the T3SS machinery. Because nitric oxide released by the host inflammatory response increases nitrate concentration, we sought to determine the effect of the inflammatory response on initiation of EHEC microcolony-formation.

Results

The colony-forming capacity was increased in accordance with the increase of nitrate in the medium. The addition of the nitric oxide-producing agent NOR-4 also enhanced the adherence capacity, which was dependent on nitrate reductase encoded by the narGHJI genes. Culture supernatant of epithelial cells, which was stimulated by a cytokine mixture, enhanced the colony-forming capacity of wild-type EHEC but not of the narGHJI mutant. Finally, colony formation by wild-type EHEC on epithelial cells, which were preincubated with heat-killed bacteria, was higher than the narGHJI mutant, and this effect was abolished by aminoguanidine hydrochloride, which is an iNOS (inducible nitric oxide synthase) inhibitor.

Conclusions

These results indicate that the inflammatory response enhances EHEC adherence by increasing nitrate concentration.

Is psoriasis associated with dementia or cognitive impairment? A Critically Appraised Topic

CLINICAL QUESTION

Is psoriasis associated with dementia or cognitive impairment?

BACKGROUND

Psoriasis is a multisystemic inflammatory disorder that has an unclear association with cognitive dysfunction.

OBJECTIVES

To conduct a Critically Appraised Topic that synthesizes the results from relevant observational studies.

METHODS

A systematic literature search of PubMed and Embase was conducted on 12 July 2019 to identify case-control, cross-sectional or cohort studies that investigated the association between psoriasis and cognitive impairment or dementia. Risk of bias was assessed for each study, and the results presented in a narrative synthesis.

RESULTS

Eleven studies were included for critical appraisal. Of the 11 studies, 10 compared a total of 16 574 psoriasis cases with over 45 078 controls for risk of dementia or cognitive impairment. One of the 11 studies evaluated 7118 patients with dementia for odds of psoriasis compared with 21 354 controls. Six studies were assessed to have higher risk of bias. Nine of the 11 included studies found a significant positive association between the two diseases, one study a null association, and one study an inverse association.

DISCUSSION AND RECOMMENDATION

Most of the 11 included studies found a positive association between psoriasis and either mild cognitive impairment or dementia. Brief cognitive assessments have been suggested to screen older patients with psoriasis who present with subjective cognitive complaints.

Serum homocysteine, folate and vitamin B12 levels in patients with psoriasis: a systematic review and meta-analysis

BACKGROUND

Patients with psoriasis are at increased risk for cardiovascular comorbidities. Previous studies examined the possible contribution of serum homocysteine, folate and vitamin B₁₂ to cardiovascular risks in patients with psoriasis but had conflicting conclusions.

OBJECTIVES

To perform a systematic review and meta-analysis of studies on serum homocysteine, folate and vitamin B₁₂ levels in patients with psoriasis.

METHODS

Online databases were searched on 15 February 2018 to include studies comparing serum homocysteine, folate and vitamin B₁₂ levels between patients with psoriasis and controls. A random effects model was adopted to estimate odds ratios for dichotomous data and standardized mean differences (SMDs) for continuous data.

RESULTS

A comprehensive literature search identified 24 studies eligible for inclusion. Compared with controls, patients with psoriasis had a significantly higher serum homocysteine level [SMD 0·41, 95% confidence interval (CI) 0·21-0·61; I² = 76·7%, 18 studies], a higher prevalence of hyperhomocysteinaemia (odds ratio 3·48, 95% CI 2·08-5·83; I² = 41·1%, seven studies) and a lower serum folate level (SMD -0·94, 95% CI -1·49 to -0·40; I² = 95·6%, 14 studies). However, there was no difference in serum vitamin B₁₂ levels between patients with psoriasis and the control group (SMD 0·004, 95% CI -0·49 to 0·50; I² = 92%, 11 studies). Metaregression analysis revealed a significant inverse correlation between the SMD of homocysteine levels and folate levels.

CONCLUSIONS

Patients with psoriasis might have higher serum homocysteine and lower folate levels than control patients without psoriasis. However, due to significant heterogeneity and other limitations, the associations require further examinations in more studies.

Activation of lpxR gene through enterohaemorrhagic Escherichia coli virulence regulators mediates lipid A modification to attenuate innate immune response

During the course of infection, pathogens must overcome a variety of host defence systems. Modulation of lipid A, which is a strong stimulant for host immune systems, is one of the strategies used by microorganisms to evade the host response. The lpxR gene, which encodes a lipid A 3'-O-deacylase, is commonly found in several pathogens and has been shown to reduce the inflammatory response. Here, we demonstrated that the lpxR gene of enterohaemorrhagic Escherichia coli (EHEC) was positively regulated by two virulence regulators, Pch and Ler, and that this regulation was coordinated with the locus of enterocyte effacement genes, which encode major virulence factors for colonisation. The lpxR promoter was repressed by the binding of H-NS, but the competitive binding of both regulators resulted in transcription activation. Next, we showed that lipid A from the lpxR mutant was more stimulatory of the inflammatory response in macrophage-like cells than lipid A from wild-type EHEC. Furthermore, phagocytic activity and phagosome maturation in host cells infected with the lpxR mutant were increased in a p38 mitogen-activated protein kinase-dependent manner in comparison with wild-type EHEC infection. Finally, we demonstrated that the pch mutant, which is deficient in activation of the locus of enterocyte effacement genes, was phagocytised more efficiently than the wild type. Thus, EHEC modulates lipid A to dampen the host immune response when activating virulence genes for colonisation.

Alcohol intake and risk of nonmelanoma skin cancer: a systematic review and dose-response meta-analysis

Nonmelanoma skin cancer (NMSC) comprises mainly basal cell carcinoma (BCC) and cutaneous squamous cell carcinoma (cSCC). The association between alcohol intake and NMSC has been inconclusive; therefore the objective of this study is to quantify the relationship between alcohol intake and NMSC using meta-analyses. A systematic literature search of PubMed and Embase was performed on 30 October 2016. Eligible articles were case-control or cohort studies that examined alcohol intake and risk of BCC or cSCC and reported relative risks (RRs) with 95% confidence intervals (CIs). Of the 307 articles identified, 13 case-control and cohort studies were included in the systematic review, including 95 241 NMSC cases (91 942 BCC and 3299 cSCC cases). A random-effects model was used to obtain summary RRs and 95% CIs for dose-response meta-analyses. For every 10-gram increase in ethanol intake per day, a positive association was found for both BCC (summary RR of 1·07; 95% CI 1·04-1·09) and cSCC (summary RR of 1·11; 95% CI 1·06-1·16). While there was evidence suggesting a nonlinear association for BCC, it may be due to the sparse data at higher alcohol intake levels. This meta-analysis found evidence that alcohol drinking is positively associated with both BCC and cSCC risk in a dose-dependent manner. These results should be interpreted with caution due to potential residual confounding. Nonetheless, because alcohol drinking is a prevalent and modifiable behaviour, it could serve as an important public health target to reduce the global health burden of NMSC.

Enterohaemorrhagic Escherichia coli produces outer membrane vesicles as an active defence system against antimicrobial peptide LL-37

Antimicrobial peptides (AMPs) are important components of the innate immune system. Enterohaemorrhagic Escherichia coli (EHEC), a food-borne pathogen causing serious diarrheal diseases, must overcome attack by AMPs. Here, we show that resistance of EHEC against human cathelicidin LL-37, a primary AMP, was enhanced by butyrate, which has been shown to act as a stimulant for the expression of virulence genes. The increase of resistance depended on the activation of the ompT gene, which encodes the outer membrane protease OmpT for LL-37. The expression of the ompT gene was enhanced through the activation system for virulence genes. The increase in ompT expression did not result in an increase in OmpT protease in bacteria but in enhancement of the production of OmpT-loaded outer membrane vesicles (OMVs), which primarily contributed to the increase in LL-37-resistance. Furthermore, a sublethal dosage of LL-37 stimulated the production of OMVs. Finally, we showed that OMVs produced by OmpT-positive strains protect the OmpT-negative strain, which is susceptible to LL-37 by itself more efficiently than OMVs from the ompT mutant. These results indicate that EHEC enhances the secretion of OmpT-loaded OMVs in coordination with the activation of virulence genes during infection and blocks bacterial cell attack by LL-37.

Modulation of the Inflammasome Signaling Pathway by Enteropathogenic and Enterohemorrhagic Escherichia coli

Innate immunity is an essential component in the protection of a host against pathogens. Enteropathogenic and enterohemorrhagic Escherichia coli (EPEC and EHEC, respectively) are known to modulate the innate immune responses of infected cells. The interference is dependent on their type III secretion system (T3SS) and T3SS-dependent effector proteins. Furthermore, these cytosolically injected effectors have been demonstrated to engage multiple immune signaling pathways, including the IFN/STAT, MAPK, NF-κB, and inflammasome pathways. In this review, recent work describing the interaction between EPEC/EHEC and the inflammasome pathway will be discussed.

Enteropathogenic Escherichia coli Uses NleA to Inhibit NLRP3 Inflammasome Activation

Enteropathogenic and enterohemorrhagic Escherichia coli (EPEC and EHEC) are related strains capable of inducing severe gastrointestinal disease. For optimal infection, these pathogens actively modulate cellular functions through the deployment of effector proteins in a type three secretion system (T3SS)-dependent manner. In response to enteric pathogen invasion, the Nod-like receptor pyrin domain containing (NLRP) inflammasome has been increasingly recognized as an important cytoplasmic sensor against microbial infection by activating caspase-1 and releasing IL-1β. EPEC and EHEC are known to elicit inflammasome activation in macrophages and epithelial cells; however, whether the pathogens actively counteract such innate immune responses is unknown. Using a series of compound effector-gene deletion strains of EPEC, we screened and identified NleA, which could subdue host IL-1β secretion. It was found that the reduction is not because of blocked NF-κB activity; instead, the reduction results from inhibited caspase-1 activation by NleA. Immunostaining of human macrophage-like cells following infection revealed limited formation of inflammasome foci with constituents of total caspase-1, ASC and NLRP3 in the presence of NleA. Pulldown of PMA-induced differentiated THP-1 lysate with purified MBP-NleA reveals that NLRP3 is a target of NleA. The interaction was verified by an immunoprecipitation assay and direct interaction assay in which purified MBP-NleA and GST-NLRP3 were used. We further showed that the effector interacts with regions of NLRP3 containing the PYD and LRR domains. Additionally, NleA was found to associate with non-ubiquitinated and ubiquitinated NLRP3 and to interrupt de-ubiquitination of NLRP3, which is a required process for inflammasome activation. Cumulatively, our findings provide the first example of EPEC-mediated suppression of inflammasome activity in which NieA plays a novel role in controlling the host immune response through targeting of NLRP3.

Enteropathogenic Escherichia coli (EPEC) and enterohemorrhagic E. coli (EHEC) cause severe intestinal dysfunction, including watery diarrhea or severe bloody diarrhea, and acute kidney failure (hemolytic uremic syndrome). Transmitted through ingestion of contaminated food, these pathogens colonize and disrupt the linings of intestinal epithelial cells. EPEC and EHEC interrupt many cellular functions, including the inflammation response, to increase their chances of proliferation and survival in the intestine. Upon detection of the invasion, epithelial cells and immune cells secrete inflammatory cytokines to further boost the immune response for efficient clearance of the pathogens. IL-1β is an important inflammatory cytokine, and its secretion is regulated by a multimeric protein complex, termed the inflammasome, in host cells. In this study, we discovered that EPEC injects a bacterial effector protein, NleA, to inhibit the secretion of IL-1β. Exploring the potential mechanisms, we found that NleA does so by directly associating with NLRP3 (Nod-Like Receptor 3), one of the three basic components of the inflammasome, and that the presence of NleA interrupts the de-ubiquitination of NLRP3, which is a prerequisite for the assembly of the inflammasome. As a result, NleA reduces the formation of the NLRP3 inflammasome and negatively regulates the secretion of IL-1β.

LeuO enhances butyrate-induced virulence expression through a positive regulatory loop in enterohaemorrhagic Escherichia coli

Enterohaemorrhagic Escherichia coli (EHEC) causes bloody diarrhoea and other severe symptoms such as haemorrhagic uraemic syndrome. The expression of virulence genes on the locus for enterocyte effacement (LEE) and associated genes is regulated by a variety of factors, including transcriptional regulators and environmental signals. Butyrate, one of the major short-chain fatty acids present in the intestine, enhances expression of LEE genes and flagella biosynthesis genes in EHEC O157:H7, resulting in increased bacterial adherence and motility. Here, we show that expression of the leuO gene, which encodes a LysR-type transcriptional regulator, is enhanced by butyrate via Lrp, which is also necessary for butyrate-induced responses of LEE genes. LeuO expression induces prolonged activation of the promoter of LEE1 operon, including the ler gene, as well as virulence mechanisms such as microcolony formation. Activation of the LEE1 promoter by LeuO depends on another regulator, called Pch. The response of the leuO promoter to butyrate requires two virulence regulators, Pch and Ler, in addition to Lrp. Pch, Ler and Lrp bind the upstream region of the leuO promoter. Thus, leuO is involved in butyrate-enhanced expression of LEE genes through a positive feedback mechanism, but its expression and action on the LEE1 promoter are dependent on the virulence regulators Pch and Ler.

Antisense transcription regulates the expression of the enterohemorrhagic Escherichia coli virulence regulatory gene ler in response to the intracellular iron concentration

Enteric pathogens, such as enterohemorrhagic E. coli (EHEC) O157:H7, encounter varying concentrations of iron during their life cycle. In the gastrointestinal tract, the amount of available free iron is limited because of absorption by host factors. EHEC and other enteric pathogens have developed sophisticated iron-responsive systems to utilize limited iron resources, and these systems are primarily regulated by the Fur repressor protein. The iron concentration could be a signal that controls gene expression in the intestines. In this study, we explored the role of iron in LEE (locus for enterocyte effacement) virulence gene expression in EHEC. In contrast to the expression of Fur-regulated genes, the expression of LEE genes was greatly reduced in fur mutants irrespective of the iron concentration. The expression of the ler gene, the LEE-encoded master regulator, was affected at a post-transcription step by fur mutation. Further analysis showed that the loss of Fur affected the translation of the ler gene by increasing the intracellular concentration of free iron, and the transcription of the antisense strand was necessary for regulation. The results indicate that LEE gene expression is closely linked to the control of intracellular free iron homeostasis.

Correlating 2-MIB and microcystin concentrations with environmental parameters in two reservoirs in South Taiwan

Cyanobacteria are present in many drinking water reservoirs in Taiwan, and some of them may produce off-flavour compounds and natural toxins. To investigate the correlation among two groups of cyanobacterial metabolites, microcystins and 2-methylisoborneol (2-MIB), and other environmental parameters, approximately 22 water quality and meteorological parameters were monitored for two source waters (Moo-Tan and Tseng-Wen reservoirs) in south Taiwan from August 2003 to April 2005. Monitoring results showed that the two groups of cyanobacterial metabolites were present in the source waters. Concentrations of 2-30 ng/L of 2-MIB was observed for the two reservoirs, while that of the total concentrations of the five microcystin congeners measured were between 30 and 340 ng/L. The concentration of both 2-MIB and microcystins showed higher concentrations in warmer seasons. A stepwise regression technique was employed to correlate 2-MIB and microcystins concentrations with all the corresponding water quality and meteorological parameters. Correlations among 2-MIB concentration, microcystin concentration, water temperature and air temperature were found in the water samples collected from both reservoirs. The correlations may provide a simple means for the water utility to anticipate the two groups of cyanobacterial metabolites in the two source waters.

Multipotential differentiation ability of GATA-1-null erythroid-committed cells

GATA-1, a zinc finger transcription factor, has been believed to be indispensable for the survival of proerythroblasts. However, we found that GATA-1-null proerythroblasts could survive and proliferate on OP9 stroma cells in the presence of erythropoietin. Furthermore, myeloid and mast cells were induced from the GATA-1-null proerythroblasts by the stimulation of granulocyte-macrophage colony-stimulating factor (GM-CSF) and interleukin-3 (IL-3), respectively, but lymphoid differentiation was not achieved by in vivo transfer. Thus, without activity of the transcription factor required for terminal differentiation, even relatively mature and committed cells proliferate continuously with the differentiation capacity to other lineages. Our data suggest that GATA-1 is a critical transcription factor to fix erythroid progenitors to the erythroid lineage.

Redirecting differentiation of hematopoietic progenitors by a transcription factor, GATA-2

GATA-2 is a zinc finger transcription factor essential for differentiation of immature hematopoietic cells. We analyzed the function of GATA-2 by a combined method of tetracycline-dependent conditional gene expression and in vitro hematopoietic differentiation from mouse embryonic stem (ES) cells using OP9 stroma cells (OP9 system). In the presence of macrophage colony-stimulating factor (M-CSF), the OP9 system induced macrophage differentiation. GATA-2 expression in this system inhibited macrophage differentiation and redirected the fate of hematopoietic differentiation to other hematopoietic lineages. GATA-2 expression commencing at day 5 or day 6 induced megakaryocytic or erythroid differentiation, respectively. Expression levels of PU.1, a hematopoietic transcription factor that interferes with GATA-2, appeared to play a critical role in differentiation to megakaryocytic or erythroid lineages. Transcription of PU.1 was affected by histone acetylation induced by binding of GATA-2 to the PU.1 promoter region. This study demonstrates that the function of GATA-2 is modified in a context-dependent manner by expression of PU.1, which in turn is regulated by GATA-2.

Analysis of the ethylene response in the epinastic mutant of tomato

Ethylene can alter plant morphology due to its effect on cell expansion. The most widely documented example of ethylene-mediated cell expansion is promotion of the "triple response" of seedlings grown in the dark in ethylene. Roots and hypocotyls become shorter and thickened compared with controls due to a reorientation of cell expansion, and curvature of the apical hook is more pronounced. The epinastic (epi) mutant of tomato (Lycopersicon esculentum) has a dark-grown seedling phenotype similar to the triple response even in the absence of ethylene. In addition, in adult plants both the leaves and the petioles display epinastic curvature and there is constitutive expression of an ethylene-inducible chitinase gene. However, petal senescence and abscission and fruit ripening are all normal in epi. A double mutant (epi/epi;Nr/Nr) homozygous for both the recessive epi and dominant ethylene-insensitive Never-ripe loci has the same dark-grown seedling and vegetative phenotypes as epi but possesses the senescence and ripening characteristics of Never-ripe. These data suggest that a subset of ethylene responses controlling vegetative growth and development may be constitutively activated in epi. In addition, the epi locus has been placed on the tomato RFLP map on the long arm of chromosome 4 and does not demonstrate linkage to reported tomato CTR1 homologs.

Fine-needle aspiration of a metaplastic breast carcinoma with extensive melanocytic differentiation: a case report

Metaplastic carcinomas of the breast are uncommon breast tumors with aberrant cellular differentiation, most commonly showing ductal, squamous, and mesenchymal components. A breast carcinoma composed of both epithelial and melanocytic differentiation is rare, with only four previously reported cases in the literature. We present the fifth reported case, where the diagnosis was suggested by fine-needle aspiration (FNA) and later confirmed after the surgical specimen was excised. Histologically, this neoplasm revealed multidirectional differentiation, consisting primarily of squamous and melanocytic cell types, with focal glandular and osseous metaplasia. Based on the morphologic, immunohistochemical, and ultrastructural findings, we conclude that such tumors fall within the spectrum of metaplastic carcinomas of the breast. We believe that this case will further contribute to the understanding of this enigmatic tumor.

[Karyotype analysis of Carpesium cernuum]

The paper reported the chromosome number, karyotype and chromosome volume of Carpesium cernuum. The normal diploid was 2n = 40, karyotype formula based on Levan's publication was k(2n) = 40 = 24 m + 12 sm + 2 st + 2T. According to the method of S. R. Kuo, the chromosome relative length was 2n = 40 = 8L + 6M2 + 16M1 + 10S, which belong to "2B" type according to the Stebbins' karyotype classification. The AS.K% was 62.35% from Arano's method. The total volume of chromosome groups was 13.76 microns 3.

Retroperitoneal ganglioneuroma: a report of diagnosis by fine-needle aspiration cytology

Ganglioneuroma is a rare benign tumor composed of nerve fibers and mature ganglion cells. Because it shares morphologic features with other neural tumors, both benign and malignant, accurate preoperative diagnosis is often difficult, but nonetheless, critical for proper management. The use of fine-needle aspiration (FNA) cytology in the diagnosis of ganglioneuroma has been rarely documented. In this report, a 25-yr-old man presented with a large retroperitoneal ganglioneuroma that was initially diagnosed by FNA cytology. This case illustrates the utility of FNA cytology in the diagnosis of ganglioneuroma and supports the routine incorporation of FNA cytology in the evaluation of retroperitoneal masses.

[Karyotype analysis on Iris lactea ssp. chinensis]

In this paper, the chromosome number, karyotype and chromosome volume of Iris lactea ssp. chinensis were reported. The normal diploid was 2n = 32. Karyotype formula was based on Levan's publication in 1964, k (2n) = 32 = 22 m + 8 sm + 2T. According to the method of Kuo SR, the species chromosome based on the relative length was 2n = 32 = 6L + 4 M2 + 18 M1 + 4 S which belong to "2A" type according to the Stebbins' karyotype classification. The AS.K% was 62.5% from Arano's method. The total volume of chromosome groups was 34.95 micron 3.

Amino acid residues in both the protein splicing and endonuclease domains of the PI-SceI intein mediate DNA binding

A structure-based model describing the interaction of the two-domain PI-SceI endonuclease with its 31-base pair DNA substrate suggests that the endonuclease domain (domain II) contacts the cleavage site region of the substrate, while the protein splicing domain (domain I) interacts with a distal region that is sufficient for high affinity binding. To support this model, alanine-scanning mutagenesis was used to assemble a set of 49 PI-SceI mutant proteins that were purified and assayed for their DNA binding and cleavage properties. Fourteen mutant proteins were 4- to >500-fold less active than wild-type PI-SceI in cleavage assays, and one mutant (T225A) was 3-fold more active. Alanine substitution at two positions in domain I reduces overall binding >60-fold by perturbing the interaction of PI-SceI with the minimal binding region. Conversely, mutations in domain II have little effect on binding, reduce binding to the cleavage site region only, or affect binding to both regions. Interestingly, substitutions at Lys301, which is part of the endonucleolytic active site, eliminate binding to the cleavage site region but permit contact with the minimal binding region. This experimental evidence demonstrates that the protein splicing domain as well as the endonuclease domain is involved in binding of a DNA substrate with the requisite length.

MCP-1-mediated chemotaxis requires activation of non-overlapping signal transduction pathways

Monocyte chemoattractant protein-1 (MCP-1) is a CC chemokine that attracts monocytes and T lymphocytes. Its receptor (CCR2) is a heptahelical G-protein-coupled receptor (GPCR) whose signal transduction pathways for chemotaxis have not been completely defined. Because other GPCRs stimulate the mitogen-activated protein kinase (MAPK) cascade, we examined this pathway's activity in response to MCP-1. MCP-1 induced rapid and transient activation of MAPK in human monocytes and in Chinese hamster ovary cells expressing CCR2B. This effect was largely insensitive to pertussis toxin and wortmannin, and was protein kinase C-dependent and protein tyrosine kinase-independent. PD 098059, an inhibitor of MEK activation, not only prevented MAPK activation but also inhibited MCP-1-induced chemotaxis. Because pertussis toxin and wortmannin also efficiently inhibit chemotaxis but do not completely inhibit MAPK activation, these data may define non-overlapping signal transduction pathways that all must be activated to produce chemokine-mediated chemotaxis.

[An immunocytochemical study of neuropeptide-like in a ciliated protozoan, Stylonychia mytilus]

An immunocytochemical investigation with both B-SA and ABC methods, under LM and EM, was carried out on Stylonychia mytilus by using 7 antisera to vertebrate neuropeptides, hormones and TH. The immunotests showed the presence of substance p-, neuropeptide y-, cck-8-, somatostatin-, beta-endorphin, adrenocorticotropic hormone-, and TH-like immunoreactive molecules in Stylonychia mytilus. The distributions of these immunoreactive substances in Stylonychia mytilus were described.

On-line sensors for coagulation proteins: concept and progress report

The assessment of blood damage and of the activation of the coagulation, complement and/or inflammatory systems by cardiovascular and extracorporeal devices is difficult at best. Immunoassay methods are now available for the measurement of many of the proteins, enzymes and peptides involved in coagulation, thrombosis, complement and inflammation. We present a long-range project and plan to develop an array of remote, on-line, semicontinuous immunosensors for selected coagulation proteins, based on fluoroimmunoassay principles. The free/bound separation step is performed optically. Excitation of fluorescence is performed via an evanescent wave produced by total internal reflection and waveguide optics. Fluorescence emission is collected only in the near field. Means to deliver fluorescently-labelled reagent and to modify the antigen-antibody binding constant are presented and discussed. The results of non-specific binding, plasma-blood fluorescence, and blood compatibility are also discussed.

Uterine contractility and oxytocin sensitivity in preterm, term, and postterm pregnancy

The records of 117 patients who had serial nonstress tests (N = 285) and oxytocin challenge tests (N = 268) were analyzed to determine whether baseline uterine contractility and/or oxytocin sensitivity changed with increasing gestational age. The results obtained in patients who were delivered before, at, and after term were compared. Uterine contractility and oxytocin sensitivity increased in all groups as gestational age progressed. No significant differences in uterine contractility were noted among groups; however, oxytocin sensitivity was significantly increased in the preterm group (p less than 0.001) and decreased in the postterm group (p less than 0.001). Our results suggest that the response of the uterus to oxytocin early in pregnancy may help to identify patients who will be delivered before or after term.