Enhancing classical swine fever virus identification: the advantages of Field-LAMP testing

Classical swine fever virus (CSFV) identification has witnessed significant advancements with the development of rapid reverse-transcription loop-mediated isothermal amplification (RT-LAMP) assays. However, conventional RT-LAMP assays for CSFV diagnosis are hindered by a laborious RNA extraction step. Moreover, the need for thermal incubators and expensive micropipettes has limited their application in field settings. Addressing these challenges, our study presents a groundbreaking solution-an electro-free and point-of-care (POC) tool known as the field-LAMP assay-for the rapid clinical detection of CSFV. By eliminating the RNA extraction requirement, advancing the colorimetric read-out and lyophilized reaction reagents, our field-LAMP assay streamlines the diagnostic process, saving valuable time and effort. This novel approach also overcomes the dependency on electric-dependent thermal incubators and expensive micropipettes, making it practical and accessible for use in the field. The successful development of the field-LAMP assay marks a significant milestone in CSFV detection. This electro-free and POC tool offers several advantages, including its ability to deliver rapid results without compromising accuracy, facilitating prompt response and containment measures.

Efficacy of DYRK1A inhibitors in novel models of Down syndrome acute lymphoblastic leukemia

Not available.

Biomedical doctoral students' research practices when facing dilemmas: two vignette-based randomized control trials

Our aim was to describe the research practices of doctoral students facing a dilemma to research integrity and to assess the impact of inappropriate research environments, i.e. exposure to (a) a post-doctoral researcher who committed a Detrimental Research Practice (DRP) in a similar situation and (b) a supervisor who did not oppose the DRP. We conducted two 2-arm, parallel-group randomized controlled trials. We created 10 vignettes describing a realistic dilemma with two alternative courses of action (good practice versus DRP). 630 PhD students were randomized through an online system to a vignette (a) with (n = 151) or without (n = 164) exposure to a post-doctoral researcher; (b) with (n = 155) or without (n = 160) exposure to a supervisor. The primary outcome was a score from - 5 to + 5, where positive scores indicated the choice of DRP and negative scores indicated good practice. Overall, 37% of unexposed participants chose to commit DRP with important variation across vignettes (minimum 10%; maximum 66%). The mean difference [95%CI] was 0.17 [- 0.65 to 0.99;], p = 0.65 when exposed to the post-doctoral researcher, and 0.79 [- 0.38; 1.94], p = 0.16, when exposed to the supervisor. In conclusion, we did not find evidence of an impact of postdoctoral researchers and supervisors on student research practices.Trial registration: NCT04263805, NCT04263506 (registration date 11 February 2020).

Individual-level permethrin exposure biomarkers in U.S. army soldiers: comparison of two treatment formulations for military uniforms

BACKGROUND

Evidence suggests that wearing permethrin-treated military uniforms is not associated with current adverse health conditions. However, exposure through this route results in permethrin biomarker concentrations considerably higher than those in the U.S.

POPULATION

The U.S. Army is exploring different methods of uniform treatment that reduce exposure while maintaining effective protection from insect vector-borne diseases.

OBJECTIVE

To compare permethrin exposure when wearing two types of permethrin-treated military uniforms.

METHODS

Eight male soldiers participated in a 32-day crossover design study to compare permethrin exposure when wearing the current Army uniform (CurrU) and a uniform with a new applied fabric treatment (NewU). Each soldier wore the uniforms for designated 8 h/day time periods over 3 consecutive days separated by a 'wash-out' week of no exposure. Permethrin exposure was assessed from the urinary concentrations of 3-phenoxybenzoic acid (3-PBA) and of the sum of cis- and trans-3-(2,2-dichlorovinyl)-2,2-dimethylcyclopropane-1-carboxylic acid (∑DCCA). Estimated dose was determined based on ∑DCCA concentrations.

RESULTS

Permethrin exposure biomarkers were 21% (3-PBA, p = 0.025) and 35% (∑DCCA, p < 0.001) lower when wearing the NewU compared to the CurrU; the dose was 33% lower (p = 0.05).

SIGNIFICANCE

Findings suggest the new treatment reduces human permethrin exposure biomarkers resulting from wearing-treated military uniforms.

Increasing sample diversity in psychiatric genetics - Introducing a new cohort of patients with schizophrenia and controls from Vietnam - Results from a pilot study

OBJECTIVES

Genome-Wide Association Studies (GWAS) of Schizophrenia (SCZ) have provided new biological insights; however, most cohorts are of European ancestry. As a result, derived polygenic risk scores (PRS) show decreased predictive power when applied to populations of different ancestries. We aimed to assess the feasibility of a large-scale data collection in Hanoi, Vietnam, contribute to international efforts to diversify ancestry in SCZ genetic research and examine the transferability of SCZ-PRS to individuals of Vietnamese Kinh ancestry.

METHODS

In a pilot study, 368 individuals (including 190 SCZ cases) were recruited at the Hanoi Medical University's associated psychiatric hospitals and outpatient facilities. Data collection included sociodemographic data, baseline clinical data, clinical interviews assessing symptom severity and genome-wide SNP genotyping. SCZ-PRS were generated using different training data sets: (i) European, (ii) East-Asian and (iii) trans-ancestry GWAS summary statistics from the latest SCZ GWAS meta-analysis.

RESULTS

SCZ-PRS significantly predicted case status in Vietnamese individuals using mixed-ancestry (R² liability = 4.9%, p = 6.83 × 10^-8), East-Asian (R² liability = 4.5%, p = 2.73 × 10^-7) and European (R² liability = 3.8%, p = 1.79 × 10^-6) discovery samples.

DISCUSSION

Our results corroborate previous findings of reduced PRS predictive power across populations, highlighting the importance of ancestral diversity in GWA studies.

Evaluation of Undiagnosed HIV Estimates Computed from the CD4 Depletion Model in a Rural, Medium-low HIV Prevalence State

The CD4 depletion model estimates diagnosis delays by approximating infection date from CD4 T-cell count at diagnosis, and back-calculation can compute the proportion of undiagnosed PLWHA. The model assumes the immigration of PLWHA to the U.S. is negligible and counts as a transmission event, which may be impractical outside high prevalence states. Duration of U.S. residency among foreign-born PLWHA and diagnosis delays were compared. The impact on estimates of undiagnosed PLWHA was tested through simulation with different proportions of foreign-born people assumed to have acquired HIV abroad. In 67% of foreign-born people, the mean (SD) years of delay (9.9 (6.3)) exceeded the duration of U.S. residency (2.0 (1.9)). Additionally, inaccuracies in the estimates for proportions of undiagnosed PLWHA were pronounced when foreign-born people who acquired HIV abroad comprised 30% of diagnoses. The CD4 model inadvertently misclassified some diagnoses as in-state transmission events. Consequently, simulated results demonstrated inaccuracies and unstable calculations.

Feasibility, safety and long term outcomes of complex left main bifurcation treatment using the nano inverted t stenting: a multicentre registry

Background

The role of double stenting techniques in distal bifurcation left main (LM) disease has gaining interest over the latest years.

Purpose

We present the 3-year multicentre registry outcomes of dual stenting using ultra-thin strut stents and the Nano Inverted-T (NIT) technique in complex unprotected true LM bifurcation disease.

Methods

We analysed the procedural and medical data of consecutive patients enrolled between 1st January 2014 and 1st December 2019 in a multicentre registry for complex LM bifurcation disease treated with the double stenting technique called NIT due contraindications and/or refusal to surgical treatment. Target lesion failure (TLF) was defined as the composite of cardiovascular death, target-vessel MI (TVMI) and clinically driven target lesion revascularization (TLR).

Results

Among two hundred-ninety-five patients (138 males, mean age 70.3±12.8 years), post-operative success was achieved in 100% of cases. Contrast volume, procedural time, and radiation exposure were 139.2±23.4 ml, 15.3±4.9 min, and 1080±1034 cGy/m2 (Figure), respectively. At a mean follow-up of 39.5±0.6 months TLF rate was 6.1% (n=18) while TLR and cardiovascular mortality rates were 3.0 (n=9) and 2.6% (n=8), respectively. Clinically driven angiographic follow-up was available in 26.4% of patients at a mean time from the procedure of 7.5±0.4 months. Clinically restenosis rate was 3.3%.

Conclusions

Revascularization of complex LM bifurcation disease using the NIT double stenting technique resulted feasible and safe with a low incidence of TLF, excellent survival rate and no stent thrombosis. Figure 1.The NIT technique is based on the use of ultra-thin strut (≤80 micron) stents and double stenting starting with side branch stenting frst. The side branch stent is precisely positioned with one possibly only strut protruding into the main vessel which is balloon crushed before the implantation of the main branch stenting. The Proximal optimization technique (POT)–snuggle kissing–POT sequence is mandatory to ensure the coverage of the side branch ostium by both side branch and main branch stents. Snuggle kissing was performed placing the LCX balloon with the proximal marker at the middle rather than at the proximal marker of the LM-LAD balloon, in order to minimize the elliptical deformation of the LM stent.

Funding Acknowledgement

Type of funding sources: None. Figure 1

New species and new genus of Pseudohaploporinae (Digenea): Pseudohaploporus pusitestis sp. n. and Parahaploporus elegantus n. g., sp. n. (Digenea: Pseudohaploporinae) from Vietnamese mullet fish

Two new species of Pseudohaploporinae, Pseudohaploporus pusitestis sp. n. and Parahaploporus elegantus n. g., sp. n., are described from intestines of the Vietnamese mullet fish Moolgarda seheli and Osteomugil cunnesius, respectively. Pseudohaploporus pusitestis sp. n. differs from two known Pseudohaploporus species, P. vietnamensis and P. planiliza, by the absence of a diverticulate hermaphroditic duct and muscular sphincters at the proximal end of the hermaphroditic sac. Metrically, P. pusitestis sp. n. is close to P. vietnamensis and differs from this species and from P. planilizum by lower maximum sizes of most parameters. Parahaploporus elegantus n. g., sp. differs from representatives of Pseudohaploporus by the presence of a single testis and the armament of hermaphroditic duct and is morphologically close to trematodes of the genus Haploporus. However, P. elegantus n. g differs from all known Haploporus species from mugilids of the Indo-West Pacific by the structure of the armament of the hermaphroditic duct and also by size of body, organs and eggs. The validity of designating two new species and a new genus of trematodes is supported by ITS and 28S rDNA sequence data. Phylogenetic reconstructions showed that the new trematodes belong to the Pseudohaploporinae, which formed a well-supported cluster within the monophyletic Haploporidae.

Decorin age-related variations in the distribution of pig extracellular matrix meniscus

Menisci act like shock absorbers and transmit load across the tibiofemoral joint by increasing congruency during movements or body weight load. This leads to decreasing the resultant stress on the articular cartilages. The meniscus has a dense extracellular matrix (ECM) composed of water, different types of collagens, and proteoglycans, such as decorin, aggrecan and biglycan. Decorin (DCN) regulates collagen fibrillogenesis acting on collagen fibrils diameter and fibrils orientation to achieve the proper assembly of its network. This work investigates the spatial disposition of this fundamental protein in pig meniscus' matrix by immunohistochemistry and western blot analysis. DCN shows an increasing trend, moving from neonatal to adult pig menisci. Adult meniscus, in porcine species, is the only one that could be considered fully mature and functional, and, even if an increasing trend is seen, no precise phenotypical switch points are seen in the age stages considered in this study.

Characterization of different in vitro culture conditions to induce a fibro-chondrogenic differentiation of swine adipose-derived stem cells

Meniscus repair is still a challenge for orthopaedic surgeons as this tissue has a scarce healing potential due to the limited vascularization and to the lack of progenitor cells. Lately, several tissue engineering strategies combining cells and scaffolds have been developed. Adipose-derived stem cells (ASCs) represent a novel cell source for meniscus repair as they are easy to harvest, and they possess an intrinsic chondrogenic potential. The aim of our study was to analyze and compare the chondrogenic differentiation of swine ASCs cultured in vitro with different supplemented media. We isolated ASCs from swine adipose tissue and we placed in pellet cultures supplemented with either Bone Morphogenetic Protein (BMP)-2 and Transforming Growth Factor (TGF)-β3 or with Bone Morphogenetic Protein (BMP)-7 and Transforming Growth Factor (TGF)-β1. Samples were analyzed after 7, 14 or 21 days of culture by biochemical, histological and gene expression analysis. Our preliminary results show that BMP-2 and TGF-β3 are stronger inducers of chondrogenesis.

Animal models for cartilage repair

Cartilage lesions still represent an unsolved problem: despite the efforts of the basic and translational research, the regeneration of this tissue is far from being reached (1-3). Articular cartilage lesions can be divided in two main groups: superficial or partial defects and full-thickness defects (4, 5). Partial lesions are not able to self-heal because multipotent cells from the bone marrow cannot reach the area leading to a progressive degeneration of the tissue (6). Conversely, full-thickness injuries possess greater chances to heal because subchondral bone involvement allows for the migration of mesenchymal cells, which fill the damaged area (7, 8). However, healing occurs through the formation of a fibrocartilaginous tissue, which has different biomechanical and biological properties (9). Native hyaline cartilage has indeed specific biomechanical properties, which confer resistance to compressive and shear stresses; the reparative fibrocartilaginous tissue lacks these abilities, therefore, the surrounding healthy cartilage progressively degenerates. In the past years, several therapeutic strategies have been developed to restore the damaged cartilage, bone marrow stimulation (chondroabrasion, drilling, micro- or nano-fractures) and more recently, tissue engineering approaches (10-14). Some of these latter procedures have already been applied in clinical practice such as matrix-induced autologous chondrocyte implantation (MACI) (15) or osteochondral scaffold implantation (16). Generally, tissue engineering approaches are based on the combination of three main elements: cells (i.e. primary chondrocytes or multipotent mesenchymal cells), biocompatible scaffolds (i.e. polymers, composites, ceramics) and signaling molecules (i.e. growth factors). Moreover, several culture conditions (i.e. static or dynamic cultures) and biomechanical stimuli can be applied during the in vitro culture to promote tissue maturation (17-19). However, an in vivo culture is mandatory to validate a new engineered construct as the in vitro phase lacks the essential in vivo environmental stimuli and because the in vivo culture allows for the testing of the biocompatibility and safety of a new material (18, 19). Moreover, preclinical animal models are crucial to understand the molecular mechanisms of cartilage lesions favoring the development of new regenerative strategies (20, 21). in vivo studies on animal models should focus on the analysis of the cellular component, analyzing the maintenance of the cellular phenotype and the tumorigenicity; on the evaluation of the biocompatibility, toxicity and degradation of the biomaterial and on the assessment of the engineered construct. In this manuscript, we will review the most common preclinical animal models, which are used to understand cartilage biology and therefore to develop new tissue engineering strategies. We will focus on both small and large animal models highlighting their peculiarities, advantages and drawbacks.

Validity, reliability, and responsiveness to change of the "Osteoporosis and You" knowledge scale

We studied the Osteoporosis and You knowledge scale in 7749 participants enrolled in a clinical trial. Results confirmed its psychometric properties in a diverse audience. Baseline scores were associated with better recall of bone mineral density test results at follow-up; however, the scale was not responsive to knowledge change.

INTRODUCTION

The goal of this study was to confirm the measurement properties of the Osteoporosis and You (O&Y) knowledge scale using classic test theory methods in the 7749 men and women participating in the Patient Activation After DXA Result Notification (PAADRN) randomized controlled trial. We hypothesized a simple factor structure that would reflect the four-factor model previously published.

METHODS

We conducted psychometric analyses which included item analysis, internal consistency reliability, construct validity using exploratory and confirmatory factor analysis (EFA and CFA), comparing knowledge levels across pre-specified groups, and responsiveness to change.

RESULTS

PAADRN participants were predominantly college educated, White females with low bone density, and a moderate level of 10-year fracture risk. EFA revealed four domains closely matching those in two previous reports. While overall scale reliability was minimally acceptable at 0.68, the reliabilities of the domain subscales were unacceptably low (0.59, 0.64, 0.45, and 0.36 for the Biological, Lifestyle, Consequences, and Prevention and Treatment subscales). CFA revealed the data fit the hypothesized model reasonably well with the items loading on their expected latent variable. The scale was not responsive to change, but although not significant, improved knowledge indicated better DXA result recall at 12 and 52 weeks.

CONCLUSIONS

In the PAADRN population, the O&Y knowledge scale had psychometric properties similar to those previously reported. Over 12 and 52 weeks, participants did not demonstrate significant changes in knowledge, but those with higher knowledge at baseline were more likely to accurately recall their baseline DXA result.

Relationship of galectin-3 with obesity, IL-6, and CRP in women

PURPOSE

To evaluate the association of galectin-3 (Gal3) with obesity and inflammatory status in a cohort of metabolically healthy, predominantly African-American women with varying cardiovascular disease (CVD) risk as determined by CRP levels.

METHODS

We assessed the association between BMI and serum levels of Gal3, IL-6, CRP, and adiponectin in metabolically healthy women (N = 97) to determine the overall association between Gal3, obesity, and inflammation in groups at different CVD risk.

RESULTS

Obese women had significantly higher serum Gal3 compared to non-obese participants (P = 0.0016), although Gal3 levels were comparable among different classes of obesity. BMI (R ² = 0.1406, P = 0.0013), IL-6 (R ² = 0.0689, P = 0.035), and CRP (R ² = 0.0468, P = 0.0419), but not adiponectin, positively predicted the variance of Gal3 levels in the total study population. However, the predicting effect of BMI (R ² = 0.2923, P = 0.0125) and inflammation (R ² = 0.3138, P = 0.038) on Gal3 was only present in women at low/moderate risk of CVD (CRP ≤ 3 µg/mL).

CONCLUSIONS

Gal3 is positively correlated with obesity and inflammation in women, while the presence of elevated CVD risk may disturb the strength of Gal3 as a biomarker of inflammation.

Distinct neurobiological signatures of brain connectivity in depression subtypes during natural viewing of emotionally salient films

BACKGROUND

Establishing an evidence-based diagnostic system informed by the biological (dys)function of the nervous system is a major priority in psychiatry. This objective, however, is often challenged by difficulties in identifying homogeneous clinical populations. Melancholia, a biological and endogenous subtype for major depressive disorder, presents a canonical test case in the search of biological nosology.

METHOD

We employed a unique combination of naturalistic functional magnetic resonance imaging (fMRI) paradigms - resting state and free viewing of emotionally salient films - to search for neurobiological signatures of depression subtypes. fMRI data were acquired from 57 participants; 17 patients with melancholia, 17 patients with (non-melancholic) major depression and 23 matched healthy controls.

RESULTS

Patients with melancholia showed a prominent loss of functional connectivity in hub regions [including ventral medial prefrontal cortex, anterior cingulate cortex (ACC) and superior temporal gyrus] during natural viewing, and in the posterior cingulate cortex while at rest. Of note, the default mode network showed diminished reactivity to external stimuli in melancholia, which correlated with the severity of anhedonia. Intriguingly, the subgenual ACC, a potential target for treating depression with deep brain stimulation (DBS), showed divergent changes between the two depression subtypes, with increased connectivity in the non-melancholic and decreased connectivity in the melancholic subsets.

CONCLUSION

These findings reveal neurobiological changes specific to depression subtypes during ecologically valid behavioural conditions, underscoring the critical need to respect differing neurobiological processes underpinning depressive subtypes.

Role of nitrification in the biodegradation of selected artificial sweetening agents in biological wastewater treatment process

The biodegradation of the six artificial sweetening agents including acesulfame (ACE), aspartame (ASP), cyclamate (CYC), neohesperidindihydrochalcone (NHDC), saccharin (SAC), and sucralose (SUC) by nitrifying activated sludge was first examined. Experimental results showed that ASP and NHDC were the most easily degradable compounds even in the control tests. CYC and SAC were efficiently biodegraded by the nitrifying activated sludge, whereas ACE and SUC were poorly removed. However, the biodegradation efficiencies of the ASs were increased with the increase in initial ammonium concentrations in the bioreactors. The association between nitrification and co-metabolic degradation was investigated and a linear relationship between nitrification rate and co-metabolic biodegradation rate was observed for the target artificial sweeteners (ASs). The contribution of heterotrophic microorganisms and autotrophic ammonia oxidizers in biodegradation of the ASs was elucidated, of which autotrophic ammonia oxidizers played an important role in the biodegradation of the ASs, particularly with regards to ACE and SUC.

Measurement of numicro and nue events in an off-axis horn-focused neutrino beam

We report the first observation of off-axis neutrino interactions in the MiniBooNE detector from the NuMI beam line at Fermilab. The MiniBooNE detector is located 745 m from the NuMI production target, at 110 mrad angle (6.3 degrees) with respect to the NuMI beam axis. Samples of charged-current quasielastic numicro and nue interactions are analyzed and found to be in agreement with expectation. This provides a direct verification of the expected pion and kaon contributions to the neutrino flux and validates the modeling of the NuMI off-axis beam.

Unexplained excess of electronlike events from a 1-GeV neutrino beam

The MiniBooNE Collaboration observes unexplained electronlike events in the reconstructed neutrino energy range from 200 to 475 MeV. With 6.46x10;{20} protons on target, 544 electronlike events are observed in this energy range, compared to an expectation of 415.2+/-43.4 events, corresponding to an excess of 128.8+/-20.4+/-38.3 events. The shape of the excess in several kinematic variables is consistent with being due to either nu_{e} and nu[over ]_{e} charged-current scattering or nu_{mu} neutral-current scattering with a photon in the final state. No significant excess of events is observed in the reconstructed neutrino energy range from 475 to 1250 MeV, where 408 events are observed compared to an expectation of 385.9+/-35.7 events.

Stage-specific effects of the osmolarity of a culture medium on the development of parthenogenetic diploids in the pig

The objective of this study was to investigate the effects of osmolarity of culture media on the development of porcine parthenogenetic diploids. Oocyte-cumulus-granulosa cell complexes were collected from ovaries and then in vitro-cultured for 48 h. The mature oocytes were subjected to a single electro-stimulation (El-St; 100 micros, 1500 V/cm), treated with 5.0 microg/ml Cytochalasin B for 4h and then cultured under various conditions as described below. In Experiment 1, the diploids were cultured for 168 h after El-St in modified Whitten's medium with 256 mOsmol (mWM256), mKRB with 309 mOsmol, and mWM with 309 mOsmol (mWM309), in which the osmolarity was adjusted by addition of NaCl or mannitol, or by reduction of distilled water. In Experiment 2, the diploids were cultured in the five media used in Experiment 1 for the first 48 h, and then in mWM256 until 168 h after El-St. In Experiment 3, the diploids were cultured for the first 48 h in mWM with osmolarity adjusted from 256 to 330 mOsmol by addition of NaCl for the first 48 h and then in mWM256 until 168 h after El-St. In Experiment 4, the diploids were cultured in mWM with 290 mOsmol (mWM290) for the first period of 24, 48, or 72 h, and then in mWM256 until 168 h after El-St. In Experiment 5, after diploids were cultured in mWM290 for the first 48 h, the obtained 4-cell diploids were transferred to mWM with osmolarity adjusted from 200 to 310 mOsmol by addition of NaCl, then cultured until 168 h after El-St. All media were supplemented with 0.5mg/ml hyaluronic acid and 4.0mg/ml bovine serum albumin. The results obtained in Experiments 1-5 indicate that the osmolarity of a medium, but not the Na(+)/K(+) ratio, exerts effects on the development of diploids to the blastocyst stage. The change of osmolarity of the culture media after the 4-cell stage increased the rate of expanded blastocyst formation in porcine diploids. The optimal osmolarities of culture medium for the first 48 h after El-St (before the 4-cell stage) were 290 and 280-320 mOsmol, and those for the later period (after the 4-cell stage) were 256 and 220-270 mOsmol, respectively.

Mapping of genes controlling aluminum tolerance in rice: comparison of different genetic backgrounds

Aluminum toxicity is the main factor limiting the productivity of crop plants in acid soils, particularly in the tropics and subtropics. In this study, a doubled-haploid population derived from the rice ( Oryza sativa L.) breeding lines CT9993 and IR62266 was used to map genes controlling Al tolerance. A genetic linkage map consisting of 280 DNA markers (RFLP, AFLP and SSR) was constructed to determine the position and nature of quantitative trait loci (QTLs) affecting Al tolerance. Three characters - control root length (CRL), Al-stressed root length (SRL) and root length ratio (RR) - were evaluated for the DH lines and the parents at the seedling stage in nutrient solution. A total of 20 QTLs controlling root growth under Al stress and control conditions were detected and distributed over 10 of the 12 rice chromosomes, reflecting multigenic control of these traits. The two QTLs of largest effect, qALRR-1-1 and qALRR-8 for root length ratio (a measurement of Al tolerance) were localized on chromosomes 1 and 8, respectively. Three other QTLs in addition to qALRR-8 were apparently unique in the CT9993 x IR62266 mapping population, which may explain the high level of Al tolerance in CT9993. Comparative mapping identified a conserved genomic region on chromosome 1 associated with Al tolerance across three rice genetic backgrounds. This region provides an important starting point for isolating genes responsible for different mechanisms of aluminum tolerance and understanding the genetic nature of this trait in rice and other cereals.

Truncated equine LH beta and asparagine(56)-deglycosylated equine LH alpha combine to produce a potent FSH antagonist

Hybrid hormone preparations were prepared by combining intact and Asn(56)-deglycosylated (N(56)dg) equine (e) LH or FSH alpha subunit preparations with truncated, des(121-149)eLH beta (eLH beta t), immunopurified, intact eLH beta or equine chorionic gonadotropin beta (eCG beta) preparations, and eFSH beta. The LH receptor-binding potencies of N(56)dg-eLH alpha:eLH beta t and N(56)dg-eFSH alpha:eLH beta t hybrids were equivalent to that of eLH; however, both N(56)dg-alpha preparations were only 3-4% as active as eLH in the rat testis Leydig cell bioassay. In the granulosa cell FSH bioassay, eLH alpha:eLH beta t stimulated progesterone synthesis and induced aromatase activity, while N(56)dg-eLH alpha:eLH beta t was completely inactive at doses up to 5 microg. N(56)dg-eLH alpha:eLH beta t inhibited progesterone production and aromatase induction elicited by 0.3 ng eFSH or 2 ng human (h) FSH. The inhibitory activities of N(56)dg-eLH alpha:eLH beta and N(56)dg-eCG alpha:eLH beta t were only 10% that of N(56)dg-eLH alpha:eLH beta t. N(56)dg-eLH alpha:eCG beta did not inhibit progesterone synthesis stimulated by eFSH at all and appeared to further stimulate aromatase induction at the highest dose tested. Preincubation of N(56)dg-eLH alpha:eLH beta and N(56)dg-eLH alpha:eLH beta t for 72 h at 37 C resulted in no loss of FSH receptor-binding activity. Preincubation resulted in 50% loss of receptor-binding activity by the eFSH preparation due to subunit dissociation, while 88% of N(56)dg-eLH alpha:eFSH beta activity was lost following 72 h, 37 C preincubation. While alpha Asn(56) oligosaccharide had no effect on eLH beta hybrid stability, it did contribute to the stability of the eFSH heterodimer.

A receptor-mediated mechanism of nicotine toxicity in oral keratinocytes

Smoking and smokeless tobacco cause morbidity that originates from the epithelium lining of the skin and upper digestive tract. Oral keratinocytes (OKC) express nicotinic acetylcholine receptors (nAChRs) that bind nicotine (Nic). We studied the mechanism of the receptor-mediated toxicity of tobacco products on OKC. Preincubation of normal human OKC with Nic altered the ligand-binding kinetics of their nAChRs, suggesting that the nAChRs underwent structural changes. This hypothesis was confirmed by the finding that exposure of OKC to Nic causes transcriptional and translational changes. Through RT-PCR and immunoblotting, we found a 1.5- to 2.9-fold increase in the mRNA and protein levels of alpha3, alpha5, alpha7, beta2, and beta4 nAChR subunits. Exposure of OKC to Nic also changed the mRNA and protein levels of the cell cycle and cell differentiation markers Ki-67, PCNA, p21, cyclin D1, p53, filaggrin, loricrin, and cytokeratins 1 and 10. The nicotinic antagonist mecamylamine prevented these changes, which indicates that the Nic-induced changes in the expression of both the nAChR and the cell cycle and cell differentiation genes resulted from pharmacologic stimulation of nAChRs with Nic. To establish the relevance of these findings to the pathobiologic effects of tobacco products in vivo, we studied the above parameters in the oral tissue of rats and mice after their exposure for 3 weeks to environmental cigarette smoke or drinking water containing equivalent concentrations of Nic that are pathophysiologically relevant. The changes of the nAChRs and the cell cycle and cell differentiation genes were similar to those found in vitro. The results of indirect immunofluorescence assay of tissue specimens validated these findings. Thus, some pathobiologic effects of tobacco products in oral tissues may stem from Nic-induced alterations of the structure and function of keratinocyte nAChRs responsible for the physiologic regulation of the cell cycle by the cytotransmitter acetylcholine.

7SK small nuclear RNA binds to and inhibits the activity of CDK9/cyclin T complexes

The transcription of eukaryotic protein-coding genes involves complex regulation of RNA polymerase (Pol) II activity in response to physiological conditions and developmental cues. One element of this regulation involves phosphorylation of the carboxy-terminal domain (CTD) of the largest polymerase subunit by a transcription elongation factor, P-TEFb, which comprises the kinase CDK9 and cyclin T1 or T2 (ref. 1). Here we report that in human HeLa cells more than half of the P-TEFb is sequestered in larger complexes that also contain 7SK RNA, an abundant, small nuclear RNA (snRNA) of hitherto unknown function. P-TEFb and 7SK associate in a specific and reversible manner. In contrast to the smaller P-TEFb complexes, which have a high kinase activity, the larger 7SK/P-TEFb complexes show very weak kinase activity. Inhibition of cellular transcription by chemical agents or ultraviolet irradiation trigger the complete disruption of the P-TEFb/7SK complex, and enhance CDK9 activity. The transcription-dependent interaction of P-TEFb with 7SK may therefore contribute to an important feedback loop modulating the activity of RNA Pol II.

Chronic stavudine exposure induces hepatic mitochondrial toxicity in adult Erythrocebus patas monkeys

OBJECTIVES

To understand the mitochondrial mechanisms underlying the lactic acidosis and hepatic steatosis seen in some HIV-1-infected individuals after long-term stavudine (d4T) exposure, we have explored mitochondrial integrity in adult monkeys (Erythrocebus patas) given a daily human equivalent dose of d4T for 78 days.

STUDY DESIGN/METHODS

Three Erythrocebus patas (patas) monkeys were given 3 mg d4T orally twice daily (total 6 mg d4T), or approximately 1.2 mg d4T/kg body weight per day, for 78 days and compared with 3 unexposed animals. Blood taken from controls and from treated monkeys before and after drug exposure was subjected to a complete clinical chemistry profile. Liver and skeletal muscles were examined for oxidative phosphorylation enzyme specific activities, mitochondrial deoxyribonucleic acid (mtDNA) quantity by slot blot, and mtDNA integrity by Southern blot.

RESULTS

Clinical chemistry assays demonstrated few significant differences; however, one d4T-exposed monkey had a serum lactate of 8.1 mmol/L after 78 days of oral d4T ingestion. Specific activities of oxidative phosphorylation Complexes I, II, and IV were significantly altered in both livers and skeletal muscles from the d4T-exposed animals, compared with the controls (p < or = 0.05). Significant depletion of mitochondrial DNA was observed in livers of drug-exposed monkeys, but not in skeletal muscle (p < or = 0.05). Further examination of liver DNA by Southern blot confirmed hepatic mtDNA depletion in drug exposed animals.

CONCLUSIONS

The data suggest that direct examination of the liver may be required to elucidate clinical d4T-induced hepatotoxicity related to mitochondrial damage.

Immunological aspects of microglia: relevance to Alzheimer's disease

Alzheimer's disease (AD) is a progressive dementing neurologic illness, and the most frequent cause of dementia in the elderly. Neuritic plaques are one of the main neuropathological findings in AD, and the major protein component is the beta-amyloid protein (A beta). Another striking feature of neuritic plaques is the presence of activated microglia, cytokines, and complement components, suggestive of "inflammatory foci" within AD brain. In this review, we will examine the mechanisms by which microglia become activated in AD, emphasizing the role in the A beta protein and proinflammatory cytokines. As well, pathways for suppression of microglial activation by immunosuppressive cytokines will be described. Inflammation mediated by activated microglia is an important component of AD pathophysiology, and strategies to control this response could provide new therapeutic approaches for the treatment of AD.

Esophageal cancer prevention in zinc-deficient rats: rapid induction of apoptosis by replenishing zinc

BACKGROUND

Nutritional zinc deficiency in rats increases esophageal cell proliferation and the incidence of N-nitrosomethylbenzylamine (NMBA)-induced esophageal tumors. Replenishing zinc with a zinc-sufficient diet reduces these effects in zinc-deficient (ZD) rats. We investigated whether apoptosis was involved in the reduction of NMBA-induced esophageal tumors when ZD rats consumed a zinc-sufficient diet.

METHODS

Weanling rats were fed a ZD diet (zinc at 3-4 ppm) for 5 weeks to establish esophageal cell proliferation, then treated once with NMBA (2 mg/kg body weight), and divided into the following five groups (47-100 per group). One ZD group was fed the ZD diet, and four zinc-replenished (ZR) groups, ZR(1), ZR(24), ZR(72), and ZR(432), were fed a zinc-sufficient diet (zinc at 74-75 ppm) beginning 1, 24, 72, and 432 hours, respectively, after NMBA treatment. From 24 hours to 2 weeks after beginning a zinc-sufficient diet, esophagi from all ZR groups were analyzed for apoptosis and cell proliferation; ZD esophagi were the controls. Tumor incidence was determined 15 weeks after zinc replenishment. All statistical tests were two-sided.

RESULTS

Zinc replenishment initiated shortly after NMBA treatment effectively reduced esophageal tumorigenesis; 8% (three of 37) of ZR(1), 14% (five of 37) of ZR(24), 19% (five of 26) of ZR(72), and 48% (19 of 40) of ZR(432) rats developed esophageal tumors compared with 93% (14 of 15) of ZD animals (all P<.001). Importantly, 24 and 30 hours after zinc replenishment, esophagi had numerous apoptotic cells (% apoptotic cells: 0 hour = 2.9%, 95% confidence interval [CI] = 2.5% to 3.3%; 24 hours = 9.4%, 95% CI = 8.2% to 10.6%), and the expression of the proapoptotic Bax protein doubled. Within 48 hours, the ZR(1) epithelium was three to five cell layers thick compared with 10-20 layers before zinc replenishment.

CONCLUSIONS

Zinc replenishment of NMBA-treated ZD rats rapidly induces apoptosis in esophageal epithelial cells and thereby substantially reduces the development of esophageal cancer.

Characterization of human FSH isoforms reveals a nonglycosylated beta-subunit in addition to the conventional glycosylated beta-subunit

Human FSH consists of a mixture of isoforms that can be separated on the basis of differences in negative charge conferred by variations in the numbers of sialic acid residues that terminate oligosaccharide branches. Western analysis of human FSH isoforms separated by chromatofocusing revealed the presence of two human FSHbeta isoforms that differed in size. A low mol wt human FSHbeta isoform was associated with all FSH isoform fractions. A high mol wt human FSHbeta isoform was associated with the more acidic fractions and increased in relative abundance as the pI decreased. Characterization of representative human FSHbeta isoforms by mass spectrometry and automated Edman degradation revealed a low mol wt isoform that was not glycosylated. A high mol wt isoform was N-glycosylated at Asn residues 7 and 24. These results indicate that pituitary human FSH consists of two classes of molecules: those that possess a nonglycosylated beta-subunit and those that possess a glycosylated beta-subunit. Glycoprotein hormones are known to be elliptical molecules, and the beta-subunit oligosaccharides project outward from the short diameter, thereby increasing it. It is interesting to speculate that this change in shape might affect ultrafiltration rates, leading to differences in delivery rates to target tissues and elimination by filtration in the kidney.

The epidemiology and disease burden of rotavirus in Vietnam: sentinel surveillance at 6 hospitals

The disease burden of rotavirus diarrhea in Vietnam was assessed by surveillance of children <5 years old who were hospitalized for diarrhea at 3 centers in the north and 3 centers in the south. Rotavirus was identified in 56% (range, 47%-60%) of the 5768 patients surveyed between July 1998 and June 2000. G-typing of the first 224 strains indicated that only 2% were non-typeable, 9% were in mixed infections, and the remainder were of the common serotypes G1, G2, G3, G4, and G9. In Vietnam, diarrhea accounts for 9880 deaths per year, which is approximately 15% of all deaths among children <5 years old, or 6.5 deaths per 1000 children. If even 50% of these diarrhea-related deaths in Vietnam were due to rotavirus, the number would represent 4%-8% of all deaths among children <5 years old, 2700-5400 rotavirus-related deaths per year, and 1 death per 280-560 children during the first 5 years of life. Thus, the disease burden of rotavirus in Vietnam is substantial, and programs to encourage the use of oral rehydration should be encouraged while efforts to develop vaccines continue.

Programmed cell death of keratinocytes culminates in apoptotic secretion of a humectant upon secretagogue action of acetylcholine

The programmed cell death of the stratified squamous epithelial cells comprising human epidermis culminates in abrupt transition of viable granular keratinocytes (KC) into dead corneocytes sloughed by the skin. The granular cell-corneocyte transition is associated with a loss in volume and dry cell weight but the mechanism for and biological significance of this form of keratinocyte apoptosis remain obscure. We show that terminally differentiated KC extrude into the intercellular spaces of living epidermis the cytoplasmic buds containing randomly congregated components of the cytosol as well as filaggrin, a precursor of the natural moisturizing factor. The discharge of secretory product is reminiscent of holocrine secretion, suggesting the term ‘apoptotic secretion’ for this novel, essential step in the process of cornification. The secretory product may become a part of the glycocalyx (a.k.a. ‘intercellular cement substance’ of epidermis) and serve as a humectant that counterbalances the osmotic pressure imposed by the natural moisturizing factor located in the stratum corneum comprised by corneocytes. The apoptotic secretion commences upon secretagouge action of acetylcholine which is synthesized and released by KC. A combination of a cholinergic nicotinic agonist and a muscarinic antagonist which increases intracellular calcium levels is required to trigger the apoptotic secretion. Analysis of the relative amounts of cholinergic enzymes and receptors expressed by KC capable of secretion and the pharmacological profiles of secretion regulation revealed an upward concentration gradient of free acetylcholine in epidermis which may provide for its unopposed secretagogue action via the m1 muscarinic and the (α)7, and (α)9 nicotinic receptor types expressed by KC at the latest stage of their development in the epidermis.

Alpha-difluoromethylornithine induction of apoptosis: a mechanism which reverses pre-established cell proliferation and cancer initiation in esophageal carcinogenesis in zinc-deficient rats

Alpha-difluoromethylornithine (DFMO) is an irreversible inhibitor of ornithine decarboxylase, the first enzyme in polyamine synthesis. Previous work showed simultaneous administration of DFMO and a zinc-deficient (ZD) diet to weanling rats from the beginning inhibited the onset of zinc-deficiency-induced esophageal cell proliferation by activating apoptosis and reduced the incidence of N-nitrosomethylbenzylamine (NMBA)-induced esophageal cancer. Because esophageal cancer initiation by NMBA is very rapid in ZD rats, this study determined whether DFMO is effective in preventing esophageal carcinogenesis when administered after the establishment of a carcinogenic environment. Weanling rats were given a ZD diet for 5 weeks to establish sustained increased esophageal cell proliferation and then an intragastric dose of NMBA. Thereafter, 20 rats were switched to DFMO-containing water while nine control ZD animals remained on deionized water; all of the animals continued on the ZD diet. Esophagi were collected 15 weeks later. The upper portion was processed for immunohistochemical analysis of cell proliferation, apoptosis, and expression of related genes, and the lower was processed for polyamine content. DFMO substantially reduces the levels of esophageal putrescine and spermidine and esophageal tumor incidence from 89 to 10% in ZD rats. Importantly, DFMO-treated ZD esophagi display increased rate of apoptosis accompanied by intense bax expression and greatly reduced cell proliferation by proliferating cell nuclear antigen expression. In addition, the p16(ink4a)/retinoblastoma control at G1 to S, deregulated in ZD esophagi, is restored after DFMO treatment. These results demonstrate that DFMO, a highly effective chemopreventive agent in esophageal carcinogenesis, reverses and counteracts esophageal cell proliferation/cancer initiation in ZD animals by way of stimulating apoptosis.

IFN-gamma regulation of class II transactivator promoter IV in macrophages and microglia: involvement of the suppressors of cytokine signaling-1 protein

The discovery of the class II transactivator (CIITA) transcription factor, and its IFN-gamma-activated promoter (promoter IV), have provided new opportunities to understand the molecular mechanisms of IFN-gamma-induced class II MHC expression. Here, we investigated the molecular regulation of IFN-gamma-induced murine CIITA promoter IV activity in microglia/macrophages. In the macrophage cell line RAW264.7, IFN-gamma inducibility of CIITA promoter IV is dependent on an IFN-gamma activation sequence (GAS) element and adjacent E-Box, and an IFN response factor (IRF) element, all within 196 bp of the transcription start site. In both RAW cells and the microglia cell line EOC20, two IFN-gamma-activated transcription factors, STAT-1alpha and IRF-1, bind the GAS and IRF elements, respectively. The E-Box binds upstream stimulating factor-1 (USF-1), a constitutively expressed transcription factor. Functionally, the GAS, E-Box, and IRF elements are each essential for IFN-gamma-induced CIITA promoter IV activity. The effects of the suppressors of cytokine signaling-1 (SOCS-1) protein on IFN-gamma-induced CIITA and class II MHC expression were examined. Ectopic expression of SOCS-1 inhibits IFN-gamma-induced activation of CIITA promoter IV and subsequent class II MHC protein expression. Interestingly, SOCS-1 inhibits the constitutive expression of STAT-1alpha and its IFN-gamma-induced tyrosine phosphorylation and binding to the GAS element in CIITA promoter IV. As well, IFN-gamma-induced expression of IRF-1 and its binding to the IRF element is inhibited. These results indicate that SOCS-1 may be responsible for attenuating IFN-gamma-induced CIITA and class II MHC expression in macrophages.

Classification, clinical manifestations, and immunopathological mechanisms of the epithelial variant of paraneoplastic autoimmune multiorgan syndrome: a reappraisal of paraneoplastic pemphigus

BACKGROUND

Recent studies suggest that paraneoplastic pemphigus (PNP) is a heterogeneous autoimmune syndrome involving several internal organs and that the pathophysiological mechanisms mediating cutaneous, mucosal, and internal lesions are not limited to autoantibodies targeting adhesion molecules.

OBJECTIVE

To classify the diverse mucocutaneous and respiratory presentations of PNP and characterize the effectors of humoral and cellular autoimmunity mediating epithelial tissue damage.

METHODS

We examined 3 patients manifesting the lichen planus pemphigoideslike subtype of PNP. A combination of standard immunohistochemical techniques, enzyme-linked immunosorbent assay with desmoglein (DSG) baculoproteins, and an immunoprecipitation assay were used to characterize effectors of humoral and cellular autoimmunity in patients with PNP and in neonatal wild-type and DSG3-knockout mice with PNP phenotype induced by passive transfer of patients' IgGs.

RESULTS

In addition to the known "PNP antigenic complex," epithelial targets recognized by PNP antibodies included 240-, 150-, 130-, 95-, 80-, 70-, 66-, and 40/42-kd proteins but excluded DSG1 and DSG3. In addition to skin and the epithelium lining upper digestive and respiratory tract mucosa, deposits of autoantibodies were found in kidney, urinary bladder, and smooth as well as striated muscle. Autoreactive cellular cytotoxicity was mediated by CD8(+) cytotoxic T lymphocytes, CD56(+) natural killer cells, and CD68(+) monocytes/macrophages. Inducible nitric oxide synthase was visualized both in activated effectors of cellular cytotoxicity and their targets. Keratin 14-positive basal epithelial cells sloughed from the large airways and obstructed small airways.

CONCLUSIONS

The paraneoplastic disease of epithelial adhesion known as PNP in fact represents only 1 manifestation of a heterogeneous autoimmune syndrome in which patients, in addition to small airway occlusion and deposition of autoantibodies in different organs, may display a spectrum of at least 5 different clinical and immunopathological mucocutaneous variants (ie, pemphiguslike, pemphigoidlike, erythema multiforme-like, graft-vs-host disease-like, and lichen planus-like). We suggest that the more encompassing term "paraneoplastic autoimmune multiorgan syndrome," or PAMS, be applied. The pathophysiological mechanisms of PAMS involve both humoral and cellular autoimmunity responses. Epithelial cell membrane antigens other than DSG1 or DSG3 are targeted by effectors of PAMS autoimmunity. Apoptosis of damaged basal cells mediates epithelial clefting, and respiratory failure results possibly from obstruction of small airways with sloughed epithelial cells.

Antibodies against keratinocyte antigens other than desmogleins 1 and 3 can induce pemphigus vulgaris-like lesions

Pemphigus is an autoimmune disease of skin adhesion associated with autoantibodies against a number of keratinocyte antigens, such as the adhesion molecules desmoglein (Dsg) 1 and 3 and acetylcholine receptors. The notion that anti-Dsg antibodies alone are responsible for blisters in patients with pemphigus vulgaris (PV) stems from the ability of rDsg1 and rDsg3 to absorb antibodies that cause PV-like skin blisters in neonatal mice. Here, we demonstrate that PV IgGs eluted from rDsg1-Ig-His and rDsg3-Ig-His show similar antigenic profiles, including the 38-, 43-, 115-, and 190-kDa keratinocyte proteins and a non-Dsg 3 130-kDa polypeptide present in keratinocytes from Dsg 3 knockout mouse. We injected into Dsg 3-lacking mice the PV IgGs that did not cross-react with the 160-kDa Dsg 1 or its 45-kDa immunoreactive fragment and that showed no reactivity with recombinant Dsg 1. We used both the Dsg3(null) mice with a targeted mutation of the Dsg3 gene and the "balding" Dsg3(bal)/Dsg3(bal) mice that carry a spontaneous null mutation in Dsg3. These PV IgGs caused gross skin blisters with PV-like suprabasal acantholysis and stained perilesional epidermis in a fishnet-like pattern, indicating that the PV phenotype can be induced without anti-Dsg 3 antibody. The anti-Dsg 1 antibody also was not required, as its presence in PV IgG does not alter the PV-like phenotype in skin organ cultures and because pemphigus foliaceus IgGs produce a distinct phenotype in Dsg3(null) mice. Therefore, mucocutaneous lesions in PV patients could be caused by non-Dsg antibodies.

IL-4-activated STAT-6 inhibits IFN-gamma-induced CD40 gene expression in macrophages/microglia

The antagonism between the cytokines IFN-gamma and IL-4 is well documented, but the mechanism by which IL-4 inhibits IFN-gamma-induced gene expression is not clearly understood. CD40 is a type I transmembrane protein that is critical for proper functioning of the immune system. We have previously shown that IFN-gamma is the most potent inducer of CD40 expression by macrophages and microglia. In this report, we describe the molecular mechanisms by which IL-4 inhibits IFN-gamma-induced CD40 expression. IL-4 suppresses IFN-gamma-induced CD40 gene expression in both macrophages and microglia, and such inhibition is dependent on the activation of STAT-6. Nuclear run-on and transfection studies indicate that IL-4-mediated repression is at the transcriptional level. Furthermore, IL-4 inhibition of IFN-gamma-induced CD40 expression is specific, since IL-4 does not inhibit IFN-gamma-induced IFN-responsive factor-1 gene expression. Site-directed mutagenesis studies demonstrate that two STAT binding sites, named proximal and distal IFN-gamma-activated sequences, in the human CD40 promoter are important for IL-4 inhibition of IFN-gamma-induced CD40 promoter activity. Moreover, EMSAs indicate that IL-4-activated STAT-6 binds to these two STAT binding sites. These results suggest that IL-4 inhibition of IFN-gamma-induced CD40 gene expression is mediated by direct STAT-6 binding to the CD40 promoter.

Novel human alpha9 acetylcholine receptor regulating keratinocyte adhesion is targeted by Pemphigus vulgaris autoimmunity

Pemphigus vulgaris (PV) is a potentially fatal autoimmune mucocutaneous blistering disease. It was assumed that PV is caused by anti-desmoglein (Dsg) 3 autoimmunity because absorption of PV sera with a chimeric baculoprotein containing the Dsg 3 and IgG1 portions, rDsg3-Ig-His, eliminated disease-causing antibodies. In this study we demonstrate that rDsg3-Ig-His adsorbs out autoantibodies to different keratinocyte antigens, including a non-Dsg 3 130-kd polypeptide. Because the pool of disease-causing PV IgGs contains antibodies against the keratinocyte acetylcholine receptor (AChR), we sought to identify the targeted receptor(s). Preincubation of monkey esophagus with PV antibodies blocked specific staining of the keratinocyte cell membrane with rabbit monoepitopic antibody to alpha9 AChR, indicating that this first of its kind AChR with dual, muscarinic and nicotinic pharmacology is targeted by PV autoimmunity. Anti-alpha9 antibody stained keratinocytes in a fishnet-like intercellular pattern, and visualized a single band at approximately 50 kd in Western blots of keratinocyte membrane proteins. Using step-by-step reverse transcription polymerase chain reactions with primers based on known alpha9 sequence regions, we identified the complete reading frame of human alpha9. Its amino acid sequence showed 85% similarity with rat alpha9. Treatment of keratinocyte monolayers with anti-alpha9 antibody induced pemphigus-like acantholysis, which could be reversed either spontaneously or by using the cholinergic agonist carbachol. We conclude that alpha9 is coupled to physiological regulation of keratinocyte adhesion, and its interaction with PV IgG may lead to blister development.

Pemphigus vulgaris antibody identifies pemphaxin. A novel keratinocyte annexin-like molecule binding acetylcholine

Because pemphigus vulgaris (PV) IgGs adsorbed on the rDsg3-Ig-His baculoprotein induced blisters in neonatal mice, it was proposed that anti-desmoglein 3 (Dsg 3) autoantibody causes PV. However, we found that rDsg3-Ig-His absorbs autoantibodies to different antigens, including a non-Dsg 3 keratinocyte protein of 130 kDa. This prompted our search for novel targets of PV autoimmunity. The PV IgG eluted from a 75-kDa keratinocyte protein band both stained epidermis in a pemphigus-like pattern and induced acantholysis in keratinocyte monolayers. Screening of a keratinocyte lambdagt11 cDNA library with this antibody identified clones carrying cDNA inserts encoding a novel molecule exhibiting approximately 40% similarity with annexin-2, named pemphaxin (PX). Recombinant PX (rPX-His) was produced in Escherichia coli M15 cells, and, because annexins can act as cholinergic receptors, its conformation was tested in a cholinergic radioligand binding assay. rPX-His specifically bound [(3)H]acetylcholine, suggesting that PX is one of the keratinocyte cholinergic receptors known to be targeted by disease-causing PV antibodies. Preabsorption of PV sera with rPX-His eliminated acantholytic activity, and eluted antibody immunoprecipitated native PX. This antibody alone did not cause skin blisters in vivo, but its addition to the preabsorbed PV IgG fraction restored acantholytic activity, indicating that acantholysis in PV results from synergistic action of antibodies to different keratinocyte self-antigens, including both acetylcholine receptors and desmosomal cadherins.

Early deregulation of the the p16ink4a-cyclin D1/cyclin-dependent kinase 4-retinoblastoma pathway in cell proliferation-driven esophageal tumorigenesis in zinc-deficient rats

The p16ink4a-cyclin D1/cyclin-dependent kinase 4 (Cdk4)-retinoblastoma (Rb) pathway has emerged as a critical target in oncogenesis. The zinc-deficient (ZD), N-nitrosomethylbenzylamine (NMBA)-induced rat esophageal cancer model provides a tool to study cell proliferation and cell cycle control in cancer initiation. Weanling rats were fed a ZD or zinc-sufficient (ZS) diet for 5 weeks, and then given a dose of NMBA. After 14 weeks, esophageal tumor incidence was 88% in ZD rats with highly proliferative esophagi versus 0% in ZS rats. Expression of p16ink4a, cyclin D1, Cdk4, and Rb in relation to that of proliferating cell nuclear antigen was characterized in esophagi by immunohistochemistry at 0, 24, and 48 h, and 1, 3, 7, 10, and 14 weeks after NMBA treatment. As early as 24 h, proliferating cell nuclear antigen-positive focal hyperplastic lesions were detected in the suprabasal layers of ZD esophagi. At the same time, overexpression of cyclin D1, Cdk4, and Rb was found in the corresponding lesion in adjacent esophageal sections. By contrast, p16ink4a expression was reduced or absent. At all time points, p16ink4a showed reduced nuclear staining in ZD esophagi compared with that in ZS esophagi. In addition, increased expression of the hyperphosphorylated forms of Rb was detected in ZD esophagi by immunoblotting. Importantly, tumors were consistently observed in ZD esophagi at very early time points. These data, obtained using a unique in vivo model for esophageal cancer with rapid tumor induction, provide strong evidence for a link between deregulation of the p16ink4a-cyclin D1/Cdk4-Rb pathway and the initiation of esophageal tumors.

Involvement of STAT-1 and ets family members in interferon-gamma induction of CD40 transcription in microglia/macrophages

Cluster of differentiation (CD)-40 is a cell surface receptor belonging to the tumor necrosis factor receptor family that plays a critical role in the regulation of immune responses. We have previously shown that the cytokine interferon (IFN)-gamma induces CD40 expression in microglia. Herein, we have elucidated the molecular mechanisms underlying IFN-gamma induction of CD40 gene expression in microglia/macrophages. IFN-gamma up-regulates CD40 expression at the transcriptional level, and this regulation involves the STAT-1alpha transcription factor. Microglia from STAT-1alpha-deficient mice were refractive to IFN-gamma induction of CD40 expression, illustrating the importance of STAT-1alpha in this response. Functional analysis of the CD40 promoter indicates that two gamma activated sequence elements as well as two Ets elements are involved in IFN-gamma induction of CD40 promoter activity. STAT-1alpha binds to the gamma activated sequence elements, whereas PU.1 and/or Spi-B bind to the Ets elements. The expression of PU.1 and Spi-B, in conjuction with STAT-1alpha activation, correlates with IFN-gamma inducibility of CD40 expression. Collectively, our data demonstrate the involvement of STAT-1alpha, PU.1, and Spi-B in IFN-gamma induction of CD40 gene expression in cells of the macrophage lineage.

Linker insertion mutagenesis based on IS21 transposition: isolation of an AMP-insensitive variant of catabolic ornithine carbamoyltransferase from Pseudomonas aeruginosa

The bacterial insertion sequence IS21 when repeated in tandem efficiently promotes non-replicative cointegrate formation in Escherichia coli. An IS21-IS21 junction region which had been engineered to contain unique SalI and BglII sites close to the IS21 termini was not affected in the ability to form cointegrates with target plasmids. Based on this finding, a novel procedure of random linker insertion mutagenesis was devised. Suicide plasmids containing the engineered junction region (pME5 and pME6) formed cointegrates with target plasmids in an E.coli host strain expressing the IS21 transposition proteins in trans. Cointegrates were resolved in vitro by restriction with SalI or BglII and ligation; thus, insertions of four or 11 codons, respectively, were created in the target DNA, practically at random. The cloned Pseudomonas aeruginosa arcB gene encoding catabolic ornithine carbamoyltransferase was used as a target. Of 20 different four-codon insertions in arcB, 11 inactivated the enzyme. Among the remaining nine insertion mutants which retained enzyme activity, three enzyme variants had reduced affinity for the substrate ornithine and one had lost recognition of the allosteric activator AMP. The linker insertions obtained illustrate the usefulness of the method in the analysis of structure-function relationships of proteins.

Choline acetyltransferase, acetylcholinesterase, and nicotinic acetylcholine receptors of human gingival and esophageal epithelia

A non-neuronal cholinergic system that includes neuronal-like nicotinic acetylcholine receptors (nAChRs) has recently been described in epithelial cells that line the skin and the upper respiratory tract. Since the use of nicotine-containing products is associated with morbidity in the upper digestive tract, and since nicotine may alter cellular functions directly via nAChRs, we sought to identify and characterize a non-neuronal cholinergic system in the gingival and esophageal epithelia. mRNA transcripts for alpha3, alpha5, alpha7, and beta2 nAChR subunits, choline acetyltransferase, and the asymmetric and globular forms of acetylcholinesterase were amplified from gingival keratinocytes (KC) by means of polymerase chain-reactions. These proteins were visualized in the gingival and esophageal epithelia by means of specific antibodies. Variations in distribution and intensity of immunostaining were found, indicating that the repertoire of cholinergic enzymes and receptors expressed by the cells changes during epithelial maturation, and that an upward concentration gradient of free acetylcholine exists. Blocking of the nAChRs with mecamylamine resulted in reversible loss of cell-to-cell adhesion, and shrinking and rounding of cultured gingival KC. Activation of the receptors with acetylcholine or carbachol caused stretching and peripheral ruffling of the cytoplasmic aprons, and formation of new intercellular contacts. These results demonstrate that both the keratinizing epithelium of attached gingiva and the non-keratinizing epithelium lining the upper two-thirds of the esophageal mucosa possess a non-neuronal cholinergic system. The nAChRs expressed by these epithelia are coupled to regulation of cell adhesion and motility, and may provide a target for the deleterious effects of nicotine.

Regulated phosphorylation of the RNA polymerase II C-terminal domain (CTD)

The largest subunit of RNA polymerase II has an intriguing feature in its carboxyl-terminal domain (CTD) that consists of multiple repeats of an evolutionary conserved motif of seven amino acids. CTD phosphorylation plays a pivotal role in controlling mRNA synthesis and maturation. In exponentially growing cells, the phosphate turnover on the CTD is fast; it is blocked by common inhibitors of transcription, such as 5,6-dichloro-1-beta-D-ribofuranosylbenzimidazole and actinomycin D. Transcription-independent changes in CTD phosphorylation are observed at critical developmental stages, such as meiosis and early development.

Cytokine response to BCG infection in alcohol-fed mice

Alcoholics have increased susceptibility to infections including tuberculosis. Chronic alcohol treatment impairs host response to bovine mycobacterium infection from BCG. This study assesses the role of four cytokines (TNFalpha, IFNgamma, IL-4, and IL-10) in this impaired response. Twenty male C57BL/6 mice were pair-fed on the Lieber DiCarli control (LCD) or ethanol (LED) diets for 28 days. The LED treated subjects ate ad lib and consumed a mean of 13 g/kg/d of ethanol. After 14 days, based on body weight, subjects were randomly divided into four treatment groups of five each. Ten infected with 2x10(6) colony-forming units (CFU) of BCG by tail-vein. On day 28, the mice were sacrificed. Liver was cultured to determine the mycobacteria CFU/g tissue. Spleens were assayed for the levels of TNFalpha, IFNgamma, IL-4, and IL-10 mRNA relative to mRNA levels for a housekeeping gene using a quantitative reverse transcriptase PCR. Without BCG infection, only the mRNA for IFNgamma was increased by LED treatment, 51% (p = 0.0001). BCG infection significantly increased TNFalpha, IFNgamma, and IL-10 mRNA (p<0.0001). IL-4 mRNA decreased (p = 0.0006). Chronic LED plus BCG infection further increased TNFalpha (p = 0.002) and IFN-gamma (p = 0.04); IL-10 was unchanged, whereas IL-4 was marginally further decreased (p = 0.06). CFU/liver increased with LED (mean +/- SD, 72+/-33x10(5) vs. 39+/-17x10(5); p = 0.004). A significant direct correlation was observed between CFU and TNFalpha, r = 0.70, p = 0.03. In conclusion, BCG infection increases TNFalpha, IFNgamma, & IL-10 and decreases IL-4. CFU numbers correlate with mRNA for TNFalpha, and LED inhibits host containment of BCG infection as measured by liver CFU. This study could not identify cytokine alterations in either Th1- or Th2-type immune responses that might contribute to the impaired host response to the BCG infection.

The transcriptional inhibitors, actinomycin D and alpha-amanitin, activate the HIV-1 promoter and favor phosphorylation of the RNA polymerase II C-terminal domain

Actinomycin D and alpha-amanitin are commonly used to inhibit transcription. Unexpectedly, however, the transcription of the human immunodeficiency virus (HIV-1) long terminal repeats (LTR) is shown to be activated at the level of elongation, in human and murine cells exposed to these drugs, whereas the Rous sarcoma virus LTR, the human cytomegalovirus immediate early gene (CMV), and the HSP70 promoters are repressed. Activation of the HIV LTR is independent of the NFkappaB and TAR sequences and coincides with an enhanced average phosphorylation of the C-terminal domain (CTD) from the largest subunit of RNA polymerase II. Both the HIV-1 LTR activation and the bulk CTD phosphorylation enhancement are prevented by several CTD kinase inhibitors, including 5, 6-dichloro-1-beta-D-ribofuranosylbenzimidazole. The efficacies of the various compounds to block CTD phosphorylation and transcription in vivo correlate with their capacities to inhibit the CDK9/PITALRE kinase in vitro. Hence, the positive transcription elongation factor, P-TEFb, is likely to contribute to the average CTD phosphorylation in vivo and to the activation of the HIV-1 LTR induced by actinomycin D.

Class II transactivator and class II MHC gene expression in microglia: modulation by the cytokines TGF-beta, IL-4, IL-13 and IL-10

Microglia are the resident macrophages of the brain, and when activated, have functions including cytokine production, phagocytosis and antigen presentation. The class II MHC genes encode proteins that present antigenic peptides to helper T cells, leading to T cell activation and the development of an antigen-specific immune response. Class II MHC gene expression is strictly regulated by the class II transactivator (CIITA) transcription factor. In this study, we investigated the effects of various immunomodulatory cytokines on IFN-gamma induction of class II MHC and CIITA gene expression in microglia, both primary microglia and a murine microglial cell line, EOC 20. By flow cytometry analysis we show that IFN-gamma-induced surface expression of class II MHC molecules on EOC 20 cells can be inhibited by the cytokines TGF-beta1, IL-4 and IL-10, but not IL-13. Using a ribonuclease protection assay, we have found that TGF-beta1, IL-4 and IL-10 act by inhibiting the expression of IFN-gamma-induced CIITA mRNA and, in turn, class II MHC mRNA. TGF-beta1, IL-4, and IL-10 inhibition of IFN-gamma-induced CIITA mRNA accumulation was not due to destabilization of CIITA mRNA, suggesting an effect at the level of transcription. In primary murine microglia, IL-10 and TGF-beta1 inhibited IFN-gamma-induced CIITA and class II MHC expression. However, a discordant effect of IL-4 was noted in that IL-4 enhanced IFN-gamma-induced CIITA and class II MHC expression in primary microglia. Although some differences are observed between EOC 20 cells and primary microglia in terms of responsiveness to TGF-beta, IL-4 and IL-10, CIITA and class II MHC gene expression are coordinately modulated.