Achievement of Target Gain Larger than Unity in an Inertial Fusion Experiment

On December 5, 2022, an indirect drive fusion implosion on the National Ignition Facility (NIF) achieved a target gain G_{target} of 1.5. This is the first laboratory demonstration of exceeding "scientific breakeven" (or G_{target}>1) where 2.05 MJ of 351 nm laser light produced 3.1 MJ of total fusion yield, a result which significantly exceeds the Lawson criterion for fusion ignition as reported in a previous NIF implosion [H. Abu-Shawareb et al. (Indirect Drive ICF Collaboration), Phys. Rev. Lett. 129, 075001 (2022)PRLTAO0031-900710.1103/PhysRevLett.129.075001]. This achievement is the culmination of more than five decades of research and gives proof that laboratory fusion, based on fundamental physics principles, is possible. This Letter reports on the target, laser, design, and experimental advancements that led to this result.

Lawson Criterion for Ignition Exceeded in an Inertial Fusion Experiment

For more than half a century, researchers around the world have been engaged in attempts to achieve fusion ignition as a proof of principle of various fusion concepts. Following the Lawson criterion, an ignited plasma is one where the fusion heating power is high enough to overcome all the physical processes that cool the fusion plasma, creating a positive thermodynamic feedback loop with rapidly increasing temperature. In inertially confined fusion, ignition is a state where the fusion plasma can begin "burn propagation" into surrounding cold fuel, enabling the possibility of high energy gain. While "scientific breakeven" (i.e., unity target gain) has not yet been achieved (here target gain is 0.72, 1.37 MJ of fusion for 1.92 MJ of laser energy), this Letter reports the first controlled fusion experiment, using laser indirect drive, on the National Ignition Facility to produce capsule gain (here 5.8) and reach ignition by nine different formulations of the Lawson criterion.

Measurements of pressure-induced Kβ line shifts in ramp compressed cobalt up to 8 Mbar

We report measurements of K-shell fluorescence lines induced by fast electrons in ramp-compressed Co targets. The fluorescence emission was stimulated by fast electrons generated through short-pulse laser-solid interaction with an Al target layer. Compression up to 2.1× solid density was achieved while maintaining temperatures well below the Fermi energy, effectively removing the thermal effects from consideration. We observed small but unambiguous redshifts in the Kβ fluorescence line relative to unshifted Cu Kα. Redshifts up to 2.6 eV were found to increase with compression and to be consistent with predictions from self-consistent models based on density-functional theory.

Dietary patterns of university students in the UK: a cross-sectional study

Background

University represents a key transition into adulthood for many adolescents but there are associated concerns about health and behaviours. One important aspect relates to diet and there is emerging evidence that university students may consume poor quality diets, with potential implications for body weight and long-term health. This research aimed to characterise dietary patterns of university students in the UK and their sociodemographic and lifestyle antecedents.

Methods

An online, cross-sectional survey was undertaken with a convenience sample of 1448 university students from five UK universities (King’s College London, Universities of St Andrews, Southampton and Sheffield, and Ulster University). The survey comprised a validated food frequency questionnaire alongside lifestyle and sociodemographic questions. Dietary patterns were generated from food frequency intake data using principal components analysis. Nutrient intakes were estimated to characterise the nutrient profile of each dietary pattern. Associations with sociodemographic variables were assessed through general linear modelling.

Results

Dietary analyses revealed four major dietary patterns: ‘vegetarian’; ‘snacking’; ‘health-conscious’; and ‘convenience, red meat & alcohol’. The ‘health-conscious’ pattern had the most favourable micronutrient profile. Students’ gender, age, year of study, geographical location and cooking ability were associated with differences in pattern behaviour. Female students favoured the ‘vegetarian’ pattern, whilst male students preferred the ‘convenience, red meat & alcohol’ pattern. Less healthful dietary patterns were positively associated with lifestyle risk factors such as smoking, low physical activity and take-away consumption. The health-conscious pattern had greatest nutrient density. The ‘convenience, red meat & alcohol’ pattern was associated with higher weekly food spending; this pattern was also identified most consistently across universities. Students reporting greater cooking ability tended towards the ‘vegetarian’ and ‘health-conscious’ patterns.

Conclusions

Food intake varied amongst university students. A substantial proportion of students followed health-promoting diets, which had good nutrient profiles obviating a need for dietary intervention. However, some students consumed poor diets, incurred greater food costs and practised unfavourable lifestyle behaviours, which may have long-term health effects. University policy to improve students’ diets should incorporate efforts to promote student engagement in cooking and food preparation, and increased availability of low cost healthier food items.

Electronic supplementary material

The online version of this article (10.1186/s12937-018-0398-y) contains supplementary material, which is available to authorized users.

Alzheimer's disease pathogenesis: Is there a role for folate?

Epigenetic modifications, including changes in DNA methylation, have been implicated in a wide range of diseases including neurological diseases such as Alzheimer's. The role of dietary folate in providing methyl groups required for maintenance and modulation of DNA methylation makes it a nutrient of interest in Alzheimer's. Late onset Alzheimer's disease is the most common form of dementia and at present its aetiology is largely undetermined. From epidemiological studies, the interactions between folate, B-vitamins and homocysteine as well as the long latency period has led to difficulties in interpretation of the data, thus current evidence exploring the role of dietary folate in Alzheimer's is contradictory and unresolved. Therefore, examining the effects at a molecular level and exploring potential epigenetic mechanisms could increase our understanding of the disease and aetiology. The aim of this review is to examine the role that folate could play in Alzheimer's disease neuropathology and will focus on the effects of folate on DNA methylation which link to disease pathology, initiation and progression.

Methyl Donor Status Influences DNMT Expression and Global DNA Methylation in Cervical Cancer Cells

BACKGROUND

Methyl donor status influences DNA stability and DNA methylation although little is known about effects on DNA methyltransferases. The aim of this study was to determine whether methyldonor status influences DNA methyltransferase (Dnmt) gene expression in cervical cancer cells, and if so, whether there are associated effects on global DNA methylation.

MATERIALS AND METHODS

The human cervical cancer cell line, C4 II, was grown in complete medium and medium depleted of folate (FM+) and folate and methionine (FM). Growth rate, intracellular folate, intracellular methionine and homocysteine in the extracellular medium were measured to validate the cancer cell model of methyl donor depletion. Dnmt expression was measured by qRT PCR using relative quantification and global DNA methylation was measured using a flow cytometric method.

RESULTS

Intracellular folate and methionine concentrations were significantly reduced after growth in depleted media. Growth rate was also reduced in response to methyl donor depletion. Extracellular homocysteine was raised compared with controls, indicating disturbance to the methyl cycle. Combined folate and methionine depletion led to a significant downregulation of Dnmt3a and Dnmt3b; this was associated with an 18% reduction in global DNA methylation compared with controls. Effects of folate and methionine depletion on Dnmt3a and 3b expression were reversed by transferring depleted cells to complete medium.

CONCLUSIONS

Methyl donor status can evidently influence expression of Dnmts in cervical cancer cells, which is associated with DNA global hypomethylation. Effects on Dnmt expression are reversible, suggesting reversible modulating effects of dietary methyl donor intake on gene expression, which may be relevant for cancer progression.

[Guidelines for gastroenteropancreatic neuroendocrine tumors--what is new? What should be incorporated in daily therapeutic decisions?]

Neuroendocrine neoplasias are seldom, but increasing. This holds true for the incidence but even more for the prevalence, since patients are able to live with their disease for quite a long time. The European Neuroendocrine Tumor Society (ENETS) as well as other societies (NANETS: North American Neuroendocrine Tumor Society; NCCN: National Comprehensive Cancer Network; ESMO: European Society of Medical Oncology) have published diagnostic and therapeutic guidelines that we present in this review. We aim to summarize those actual guidelines in a practice-based diagnostic and therapeutic algorithm, but also wish to point to open questions that have to be discussed in a multidisciplinary approach.

Use of radiometric (234/238U and 228/226Ra) and mass spectrometry (87/86Sr) methods for studies of the stability of groundwater reservoirs in Central Poland

The uranium (²³⁴U/²³⁸U) and radium (²²⁸Ra/²²⁶Ra) activity ratios and ⁸⁷Sr/⁸⁶Sr isotopic ratio in thermal groundwater, subsurface water (groundwater) and river water from Poddebice and Uniejow were determined. The uranium and radium activity ratios and strontium isotopic ratio varied from 0.629 to 1.471, from 0.396 to 4.961 and from 0.708438 to 0.710344, respectively. The results for the thermal groundwater samples showed that the radiometric method together with mass spectrometry stable strontium isotope ratio measurements can be used for underground water transport studies. On the basis of the uranium and radium activity and the strontium isotopic ratio differences in subsurface water (groundwater) and in river water, any possible water influx between these adjacent reservoirs can be observed. The obtained results exclude any water transport from surface and subsurface water to thermal ground water reservoirs in this region of Poland.

Lack of prolidase causes a bone phenotype both in human and in mouse

The degradation of the main fibrillar collagens, collagens I and II, is a crucial process for skeletal development. The most abundant dipeptides generated from the catabolism of collagens contain proline and hydroxyproline. In humans, prolidase is the only enzyme able to hydrolyze dipeptides containing these amino acids at their C-terminal end, thus being a key player in collagen synthesis and turnover. Mutations in the prolidase gene cause prolidase deficiency (PD), a rare recessive disorder. Here we describe 12 PD patients, 9 of whom were molecularly characterized in this study. Following a retrospective analysis of all of them a skeletal phenotype associated with short stature, hypertelorism, nose abnormalities, microcephaly, osteopenia and genu valgum, independent of both the type of mutation and the presence of the mutant protein was identified. In order to understand the molecular basis of the bone phenotype associated with PD, we analyzed a recently identified mouse model for the disease, the dark-like (dal) mutant. The dal/dal mice showed a short snout, they were smaller than controls, their femurs were significantly shorter and pQCT and μCT analyses of long bones revealed compromised bone properties at the cortical and at the trabecular level in both male and female animals. The differences were more pronounce at 1 month being the most parameters normalized by 2 months of age. A delay in the formation of the second ossification center was evident at postnatal day 10. Our work reveals that reduced bone growth was due to impaired chondrocyte proliferation and increased apoptosis rate in the proliferative zone associated with reduced hyperthrophic zone height. These data suggest that lack of prolidase, a cytosolic enzyme involved in the final stage of protein catabolism, is required for normal skeletogenesis especially at early age when the requirement for collagen synthesis and degradation is the highest.

Physiology of Bone

Bone serves three main physiological functions: its mechanical nature provides support for locomotion and offers protection to vulnerable internal organs, it forms a reservoir for the storage of calcium and phosphate in the body, and it provides an environment for bone marrow production and haematopoietic cell development. The traditional view of bone as a passive tissue that responds to hormonal and dietary influences has changed over the past half century to one of bone as a dynamic adaptive tissue that responds to mechanical demands. This chapter gathers together some recent advances in bone physiology and molecular cell biology and discusses the potential application of the functional adaptation of bone to loading to enhance bone strength during childhood and adolescence.

Vandetanib therapy in medullary thyroid cancer

The U.S. Food and Drug Administration (FDA) approved vandetanib in April 2011 for the treatment of unresectable, locally advanced or metastatic medullary thyroid cancer (MTC). In Europe it was approved in March 2012, but only for the treatment of aggressive and symptomatic MTC. This small molecule is a tyrosine kinase inhibitor of several growth factors involved in cellular proliferation and angiogenesis, including the epidermal growth factor receptor (EGFR) and the vascular endothelial growth factor receptors 2 and 3 (VEGFR-2, VEGFR-3). In addition, vandetanib is an inhibitor of the RET (rearranged during transfection) gene, a proto-oncogene often mutated in familial MTC. Since MTC is a rare disease, for which no previous medical therapies are approved, vandetanib is the first drug shown to be effective in a large phase III trial treating patients with metastatic or locally advanced MTC. Common adverse events are diarrhea, nausea, hypertension, headache and QT prolongation that are manageable and are commonly outweighed by the benefits of vandetanib in terms of delaying disease progression and inducing tumor response.

ZM447439, a novel promising aurora kinase inhibitor, provokes antiproliferative and proapoptotic effects alone and in combination with bio- and chemotherapeutic agents in gastroenteropancreatic neuroendocrine tumor cell lines

BACKGROUND

Therapeutic approaches to gastroenteropancreatic neuroendocrine tumors (GEP-NETs) are still not satisfactory. A new direction in treatment options could be the novel aurora kinase inhibitor ZM447439, which was previously reported to interfere with the mitotic spindle integrity checkpoint and chromosome segregation, but does not interfere with other kinases when used up to 5 muM.

METHODS

We evaluated the antineoplastic effects of ZM447439 on growth and apoptosis of the GEP-NET cell lines BON, QGP-1 and MIP-101, representing the different malignant tumor types, using standard cell biological tests as crystal violet assays, caspase activation, DNA fragmentation and cell cycle analysis.

RESULTS

ZM447439 dose-dependently inhibited proliferation of all three cell lines with IC(50) values in the nanomolar to low micromolar range. Moreover, aurora kinase inhibition by ZM447439 potently induced apoptosis, which was accompanied by DNA fragmentation and caspase 3 and 7 activation. Furthermore, we observed cell cycle arrest at G(0)/G(1) phase as well as a block in G(2)/M transition. In addition, combined treatment with the chemotherapeutic agents streptozocin and cisplatin augmented significantly the antiproliferative effects of those agents.

CONCLUSION

Aurora kinase inhibition by ZM447439 seems to be a promising new therapeutic approach in GEP-NETs, which should be evaluated in further clinical trials.

Cetuximab plus cisplatin-5-fluorouracil versus cisplatin-5-fluorouracil alone in first-line metastatic squamous cell carcinoma of the esophagus: a randomized phase II study of the Arbeitsgemeinschaft Internistische Onkologie

BACKGROUND

This study assessed the activity of the mAb cetuximab in combination with cisplatin and 5-fluorouracil (5-FU) in advanced esophageal squamous cell carcinoma.

PATIENTS AND METHODS

For a maximum of six 29-day cycles, patients received cisplatin 100 mg/m(2), day 1, plus 5-FU 1000 mg/m(2), days 1-5 (CF), either alone or in combination with cetuximab (CET-CF; 400 mg/m(2) initial dose followed by 250 mg/m(2) weekly thereafter). The primary end point was tumor response. Tumor material was obtained for analysis of KRAS mutation status.

RESULTS

Sixty-two eligible patients were included, 32 receiving CET-CF and 30 CF. Cetuximab did not exacerbate grade 3/4 toxicity, except for rash (6% versus 0%) and diarrhea (16% versus 0%). The overall response rate according to RECIST criteria was 19% and 13% and the disease control rate 75% and 57% for the CET-CF and CF arms, respectively. With a median follow-up of 21.5 months, the median progression-free survival was 5.9 and 3.6 months and median overall survival 9.5 and 5.5 months for CET-CF and CF, respectively. No KRAS codon 12/13 tumor mutations were identified in 37 evaluated samples.

CONCLUSION

Cetuximab can be safely combined with CF chemotherapy and may increase the efficacy of standard CF chemotherapy.

Physiology of bone

Bone serves three main physiological functions. Its mechanical nature provides support for locomotion and offers protection to vulnerable internal organs, it forms a reservoir for storage of calcium and phosphate in the body, and it provides an environment for bone marrow and for the development of haematopoietic cells. The traditional view of a passive tissue responding to hormonal and dietary influences has changed over the past half century to one of a dynamic adaptive tissue responding to mechanical demands. This chapter gathers together some recent advances in bone physiology and molecular cell biology and discusses the potential application of the bone's functional adaptation to loading in enhancing bone strength during childhood and adolescence.

The peroxisome proliferator activator receptor alpha/delta agonists linoleic acid and bezafibrate upregulate osteoblast differentiation and induce periosteal bone formation in vivo

We showed previously that some actions of prostaglandin E(2) (PGE(2)) on bone are caused by its degradation product, PGA(2), which mediates its effects via a class of nuclear receptors known as the peroxisome proliferator activator receptors (PPARs), suggesting that the PPARs may be involved in the regulation of bone formation. The aims of this study were to determine the effects of PPARalpha/delta agonists on bone in vitro and in vivo. PPAR agonists were examined in vitro using the fibroblastic colony-forming unit (CFU-f) assay. The PPARalpha/delta agonists linoleic acid (LA) and bezafibrate (Bez) were then administered to intact male rats by daily s.c. injection for 12 weeks with either vehicle (10% dimethyl sulfoxide), LA (0.3 mg/kg), or Bez (1 mg/kg). CFU-f assays were performed on stromal cells ex vivo. Bone mineral density (BMD) and serum markers of formation and resorption were measured. Bone histomorphometry was performed at cancellous and cortical bone sites. PPARalpha/delta agonists increased significantly the number of osteoblastic colonies as demonstrated by increased alkaline phosphatase activity, collagen production, and calcification. This increase was typically equal to or greater than that achieved with the known bone anabolic agent PGE(2). In intact male rats, LA and Bez increased metaphyseal BMD by 7% and 11%, respectively. Increased BMD was associated with an increase in total bone area, although no changes were observed in bone formation rate within the trabecular compartment. Serum osteocalcin and osteoprogenitor numbers were increased, whereas there was no change in either tartrate-resistant acid phosphatase 5b or osteoclast number. Both LA and Bez increased cortical bone area by approximately 38%, periosteal perimeter by 15%, and periosteal bone formation by 221% and 140%, respectively. There was no effect on medullary cavity area or endocortical perimeter. These data suggest that PPARalpha/delta may have roles in bone anabolism, specifically in the regulation of periosteal bone formation. They are potential therapeutic targets for osteoporosis therapy.

Osteoclast-poor human osteopetrosis due to mutations in the gene encoding RANKL

Autosomal recessive osteopetrosis is usually associated with normal or elevated numbers of nonfunctional osteoclasts. Here we report mutations in the gene encoding RANKL (receptor activator of nuclear factor-KB ligand) in six individuals with autosomal recessive osteopetrosis whose bone biopsy specimens lacked osteoclasts. These individuals did not show any obvious defects in immunological parameters and could not be cured by hematopoietic stem cell transplantation; however, exogenous RANKL induced formation of functional osteoclasts from their monocytes, suggesting that they could, theoretically, benefit from exogenous RANKL administration.

Ungewöhnlicher Fall einer akuten oberen gastrointestinalen Blutung: PEG-Implantationsmetastase eines Ösophaguskarzinoms - Fallbericht und Literaturübersicht

We present the case of a patient with an esophageal squamous cell carcinoma, who was treated primarily by radiotherapy. Due to dysphagia, the patient received a percutaneous endoscopic gastrostomy (PEG) without any sign of tumour at that time. Five months later the patient presented with an upper GI bleeding from a gastric ulcer, which histologically turned out to be a metastasis of the previously diagnosed squamous cell carcinoma. So-called "implantation metastases" at the percutaneous endoscopic gastrostomy site are rare and most of the cases have been described in patients with head and neck tumours. Moreover, the presentation as an upper GI bleed is very uncommon and needs the attention of both endoscopists as well as gastrointestinal oncologists. Clinicopathological features of this case with a brief review of the literature are presented.

Characterization of the Bacillus subtilis spore morphogenetic coat protein CotO

Bacillus spores are protected by a structurally and biochemically complex protein shell composed of over 50 polypeptide species, called the coat. Coat assembly in Bacillus subtilis serves as a relatively tractable model for the study of the formation of more complex macromolecular structures and organelles. It is also a critical model for the discovery of strategies to decontaminate B. anthracis spores. In B. subtilis, a subset of coat proteins is known to have important roles in assembly. Here we show that the recently identified B. subtilis coat protein CotO (YjbX) has an especially important morphogenetic role. We used electron and atomic force microscopy to show that CotO controls assembly of the coat layers and coat surface topography as well as biochemical and cell-biological analyses to identify coat proteins whose assembly is CotO dependent. cotO spores are defective in germination and partially sensitive to lysozyme. As a whole, these phenotypes resemble those resulting from a mutation in the coat protein gene cotH. Nonetheless, the roles of CotH and CotO and the proteins whose assembly they direct are not identical. Based on fluorescence and electron microscopy, we suggest that CotO resides in the outer coat (although not on the coat surface). We propose that CotO and CotH participate in a late phase of coat assembly. We further speculate that an important role of these proteins is ensuring that polymerization of the outer coat layers occurs in such a manner that contiguous shells, and not unproductive aggregates, are formed.

Clinical, genetic, and cellular analysis of 49 osteopetrotic patients: implications for diagnosis and treatment

BACKGROUND

Osteopetrosis, a genetic disease characterised by osteoclast failure, is classified into three forms: infantile malignant autosomal recessive osteopetrosis (ARO), intermediate autosomal recessive osteopetrosis (IRO), and autosomal dominant osteopetrosis (ADO).

METHODS

We studied 49 patients, 21 with ARO, one with IRO, and 27 with type II ADO (ADO II).

RESULTS

Most ARO patients bore known or novel (one case) ATP6i (TCIRG1) gene mutations. Six ADO II patients had no mutations in ClCN7, the only so far recognised gene implicated, suggesting involvement of yet unknown genes. Identical ClCN7 mutations produced differing phenotypes with variable degrees of severity. In ADO II, serum tartrate resistant acid phosphatase was always elevated. Bone alkaline phosphatase (BALP) was generally low, but osteocalcin was high, suggesting perturbed osteoblast differentiation or function. In contrast, BALP was high in ARO patients. Elevated osteoclast surface/bone surface was noted in biopsies from most ARO patients. Cases with high osteoclasts also showed increased osteoblast surface/bone surface. ARO osteoclasts were morphologically normal, with unaltered formation rates, intracellular pH handling, and response to acidification. Their resorption activity was greatly reduced, but not abolished. In control osteoclasts, all resorption activity was abolished by combined inhibition of proton pumping and sodium/proton antiport.

CONCLUSIONS

These findings provide a rationale for novel therapies targeting pH handling mechanisms in osteoclasts and their microenvironment.

Prognostic value of nuclear survivin expression in oesophageal squamous cell carcinoma

Survivin, a new member of the family of apoptosis inhibitors, is expressed almost exclusively in proliferating cells, above all in cancers. Subcellular localisation and prognostic implications of the survivin protein have not yet been determined in oesophageal squamous cell carcinoma. The survival of 84 patients with oesophageal squamous cell carcinomas was correlated with the extent of immunohistochemical survivin expression in tumour cell nuclei. Tumours were scored positive when >5% cells stained positive. Patients were followed up for at least 5 years or until death. In normal oesophageal squamous cell epithelium, some cytoplasmic survivin expression was detected in the basal cells, whereas proliferating cells showed nuclear staining of survivin. Nuclear expression of survivin was also detected in 67 cancers (80%). The mean survival for patients of this group (28 months, range 20-36) was significantly less than that for patients without survivin expression in the tumour cell nuclei (108 months, range 62-154, P=0.003). Using univariate analysis, nuclear survivin expression (P=0.003), tumour depth (P=0.001), lymph node metastasis (P=0.003) and stage (P<0.001) were the best predictors of survival. In contrast, cytoplasmic survivin staining was noted in 53 (63%) tumours and had no prognostic relevance. In conclusion, the analysis of nuclear survivin expression identifies subgroups in oesophageal squamous cell cancer with favourable (survivin(-)) or with poor prognosis (survivin(+)). We suggest that the determination of nuclear survivin expression could be used to individualise therapeutic strategies in oesophageal squamous cell cancer in the future.

Expression of dopamine receptors and transporter in neuroendocrine gastrointestinal tumor cells

C-11- or F-18-DOPA positron emission tomography (DOPA PET) is a new sensitive imaging technique for small neuroendocrine gastrointestinal tumors which evaluates the decarboxylase activity. To further characterize the dopaminergic system in neuroendocrine gastrointestinal tumor cells, we investigated the expression of both dopamine receptors and the transmembrane dopamine transporter (DAT) in the human neuroendocrine pancreatic cell line BON and in the neuroendocrine gut cell line STC-1. Both BON and STC-1 cells expressed mRNA of the dopamine receptors D2-D5 and DAT. mRNA of the dopamine receptor D1 was detected in BON cells only. Both in BON and STC-1 cells, expression of D2 and D5 receptors and DAT was also demonstrated immunocytochemically. For functional receptor characterization intracellular cAMP levels ([cAMP]i) were determined. Whereas in STC-1 cells dopamine and the D1-like (D1/D5) receptor agonist SKF 38393 increased [cAMP]i, [cAMP]i was decreased by dopamine or the D2-like (D2-D4) receptor agonist quinpirole in BON cells. Functional DAT activity was, however, not detected in either cell line. The presence of both dopamine receptors and of the DAT suggests an autocrine and/or paracrine function of dopamine in neuroendocrine gastrointestinal tumor cells. Yet neither the transmembrane dopamine transporter nor dopamine receptors are likely to contribute to positive DOPA PET imaging of neuroendocrine gastrointestinal tumors. However, these molecules may be of diagnostic importance when applying other dopaminergic system tracers.

Molecular cloning, gene organization and expression of rainbow trout (Oncorhynchus mykiss) inducible nitric oxide synthase (iNOS) gene

A full-length inducible nitric oxide synthase (iNOS) gene has been sequenced for the first time outside the mammals, and the gene organization compared with that already determined for human iNOS. While there are some differences from the human gene, overall the exons show remarkable conservation in sequence and organization. As in human, the trout iNOS gene has 27 exons, with 18 of the trout exons being identical in size with the equivalent human exons. The cofactor-binding domains are found in the same exons and in some cases are absolutely conserved. Differences include the start of the ORF in exon 3 instead of exon 2, resulting in a deletion at the 5' end of the trout iNOS protein. Exon 27 also shows a large difference in size and although the trout exon is larger this is due to the length of the 3'-UTR. Several non-mammalian features are notable, and include a conserved potential glycosylation site in chicken and fish, and an insertion at the boundary of exons 20 and 21 in fish. The intron sizes in trout were generally much smaller than in human iNOS, making the trout iNOS gene approximately half the size of the human gene. Analysis of RNA secondary structure revealed two regions with complementarity, which could interfere with reverse transcription. Using a trout fibroblast cell line (RTG-2 cells), it was shown by reverse transcriptase (RT)-PCR that virus infection was a good inducer of iNOS expression. However, when using a combination of Superscripttrade mark II for reverse transcription and primers at the 5' end of the gene only very weak products were amplified, in contrast with the situation when primers at the 3' end of the gene were used, or ThermoScripttrade mark-derived cDNA was used. The impact of such results on RT-PCR analysis of iNOS expression in trout is discussed.

Neuroendocrine differentiation is a relevant prognostic factor in stage III-IV colorectal cancer

OBJECTIVE

To determine the prognostic relevance of neuroendocrine differentiation in colorectal cancer.

METHODS

The survival of 116 patients with colorectal cancer of stages III (n = 59) and IV (n = 57) was correlated with the extent of neuroendocrine differentiation. Chromogranin A and synaptophysin were used as neuroendocrine markers. Based on the degree of immunoreactivity for these markers, tumours were classified as 0 (no expression of neuroendocrine markers), 1 (< 2% cells staining positive for neuroendocrine markers) and 2 (> 2% cells staining positive for neuroendocrine markers). Patients were followed up for more than 5 years or until death.

RESULTS

Seven of 59 (11.8%) stage III cancers and 13/57 (22.8%) stage IV cancers belonged to group 2. The 96 patients of groups 0 and 1 lived for 48.9 months, whereas the 20 patients of group 2 survived for only 18.6 months (Kaplan-Meier survival curves, P < 0.001). The difference was most striking in stage III disease with 79.4 months' survival for combined groups 0 and 1, and 38.9 months' survival for group 2 (P < 0.01). Using the multivariate Cox regression model, the presence of more than 2% of cells with neuroendocrine differentiation was found to be an independent prognostic parameter for stage III and IV disease. No correlation was observed between neuroendocrine differentiation and tumour location, grade, depth of invasion or stage.

CONCLUSION

Neuroendocrine differentiation is often seen in colorectal cancer. It is an independent prognostic factor in stage III-IV colorectal cancer.

Expression of SIALYL-Le(x) antigen defined by MAb AM-3 is an independent prognostic marker in colorectal carcinoma patients

Expression of mucin-bound sialyl-Le(x) antigen during the progression of colorectal carcinoma and its potential prognostic value were analysed in sections of tumours from 182 patients with a documented follow-up by immunohistochemistry using the monoclonal antibody (MAb) AM-3. Two groups of colonic carcinomas with weak (n = 79) and strong (n = 103) sialyl-Le(x) expression were discerned. The percentage of strongly expressing tumours increased with the progression of the disease (UICC stage I = 10%, stage II = 46%, stage III = 63%, stage IV = 68%, p < 0.0001). Seventy-four percent of patients with carcinomas exhibiting a strong sialyl-Le(x) expression but only 34% of patients with weak sialyl-Le(x) expression died of the disease (p = 0.0026). In multivariate analysis, strong sialyl-Le(x) expression increased the relative risk of cancer-related death 3.8-fold (95% CI = 1.8-7.9, p = 0.00034). The separate analyses of patients in UICC stage II (n = 56), III (n =5 9) and IV (n = 57) revealed that strong sialyl-Le(x) expression was associated with a reduction of the 5-year overall survival rate in UICC stage II (84% vs. 54%, p = 0.0013) and in stage III patients (86% vs. 35%, p = 0.0008) after curative resection but was not relevant in patients with distant metastases. In conclusion, the strong expression of sialyl-Le(x) antigen defined by the MAb AM-3 in colorectal carcinomas is an independent unfavourable prognostic factor after curative resection in stage II and III patients. The predictive power of the sialyl-Le(x) expression may be helpful to define subgroups of patients at high risk for whom preventive adjuvant therapy can be selectively applied before the occurrence of detectable metastases.

Cognitive predictors of adherence to malaria prophylaxis regimens on return from a malarious region: a prospective study

Cases of 'imported malaria' into countries where malaria is not endemic are increasing and evidence suggests that non-use of malaria prophylaxis and lack of adherence are contributing to this increase. Non-adherence may be especially likely because chemoprophylaxis regimens require travellers to continue to take medication for 4 weeks after their return from a malarious region. This study investigated the extent to which cognition measures specified by the theory of planned behaviour and the health belief model could distinguish between those who reported greater or lesser adherence after their return. Cognitions were measured using a brief questionnaire on the day of departure from the malarious region and reports of adherence were collected between 5 and 7 weeks later. Data from two longitudinal samples of UK tourists returning from The Gambia were analysed; 106 mefloquine users and 61 chloroquine and proguanil users. Results suggested that malaria prophylaxis adherence could be improved. 22.5% of mefloquine users and 31% of chloroquine and proguanil users reported adherence for 3 weeks or less. A model based on the theory of planned behaviour explained approximately 50% of the variance in reported adherence amongst mefloquine users and 40% amongst chloroquine and proguanil users, comparing favorably with other published applications of the theory. Findings suggest that targeting key cognitions could enhance adherence on return from malarious regions. Enhancing perceived control over adherence may be important as well as emphasising susceptibility to malaria infection. Reassuring mefloquine users concerning potential side effects of the drug may also encourage adherence on return. Implications for future research are discussed.

Provision of health information by British travel agents

A study to assess the frequency of health related advice provided by travel consultants to customers planning to travel to the tropics was undertaken. A total of 202 agencies throughout the UK were visited by covert researchers requesting a package holiday for 2 weeks to Kenya or a flight to India. In a face to face consultation, the researchers recorded any health related information provided. If none were forthcoming, the agent was prompted using a standardized prompt. Thirty per cent of the agencies were based in South-east England and London and the remainder in the North, the Midlands and the South-west. No spontaneous health warnings were given in 61% (123) of consultations for malarious destinations. After prompting, 71% of agents gave general health advice, 67% suggested seeking malaria advice from a general practitioner and 37% of agents brought up the need for malaria prophylaxis for the journey. 63% of consultations included a mention of malaria after being prompted. The study reveals that travel agents provide health advice inconsistently and mention health risks only when prompted. For travellers' safety and to meet new consumer regulations, the travel industry needs to draw attention to health risks associated with its products consistently and effectively.

CD59 and CD48 expressed by rat retinal pigment epithelial cells are major ligands for the CD2-mediated alternative pathway of T cell activation

The alternative CD2-mediated pathway of T cell activation, which is independent of MHC/peptide recognition by the TCR/CD3 complex, is dependent upon two signals being received by the CD2 molecule. The natural ligand for CD2 is CD58, but controversy exists over alternative or additional ligands that could deliver the second signal in vivo. We have used rat retinal pigment epithelial cells (RPE), which lack temperature-insensitive ligands for CD2 adhesion, to study Ag-independent T cell activation. Rat RPE cells expressed high levels of CD59 and low levels of another potential CD2 ligand, CD48, both in vitro and in the in vivo model of experimental autoimmune uveoretinitis. When increasing numbers of syngeneic T cells were added to microwell cultures of rat RPE cells, the T cells, even in the absence of any exogenous stimulant in the cultures, underwent spontaneous proliferation. This effect required metabolically active RPE cells, and was IL-2 driven and enhanced in the presence of indomethacin. Proliferation was modulated by phosphatidylinositol-phospholipase C treatment of the RPE, and blocked by mAbs to CD59. Ab cross-linking of CD48 but not CD59 on the RPE was found to induce messenger RNA expression for IL-1 beta, which together with constitutively expressed IL-6 are required costimulatory factors for T cell activation through CD2. This is the first demonstration in a fully syngeneic system that bi-directional signaling involving CD59 and CD48 molecules expressed by physiologically normal, nonhematopoietic, cells can trigger T lymphocyte activation and proliferation through autocrine IL-2 production in the absence of Ag.

CD59 and CD48 expressed by rat retinal pigment epithelial cells are major ligands for the CD2-mediated alternative pathway of T cell activation

The alternative CD2-mediated pathway of T cell activation, which is independent of MHC/peptide recognition by the TCR/CD3 complex, is dependent upon two signals being received by the CD2 molecule. The natural ligand for CD2 is CD58, but controversy exists over alternative or additional ligands that could deliver the second signal in vivo. We have used rat retinal pigment epithelial cells (RPE), which lack temperature-insensitive ligands for CD2 adhesion, to study Ag-independent T cell activation. Rat RPE cells expressed high levels of CD59 and low levels of another potential CD2 ligand, CD48, both in vitro and in the in vivo model of experimental autoimmune uveoretinitis. When increasing numbers of syngeneic T cells were added to microwell cultures of rat RPE cells, the T cells, even in the absence of any exogenous stimulant in the cultures, underwent spontaneous proliferation. This effect required metabolically active RPE cells, and was IL-2 driven and enhanced in the presence of indomethacin. Proliferation was modulated by phosphatidylinositol-phospholipase C treatment of the RPE, and blocked by mAbs to CD59. Ab cross-linking of CD48 but not CD59 on the RPE was found to induce messenger RNA expression for IL-1 beta, which together with constitutively expressed IL-6 are required costimulatory factors for T cell activation through CD2. This is the first demonstration in a fully syngeneic system that bi-directional signaling involving CD59 and CD48 molecules expressed by physiologically normal, nonhematopoietic, cells can trigger T lymphocyte activation and proliferation through autocrine IL-2 production in the absence of Ag.

Rat retinal pigment epithelial cells express an inducible form of nitric oxide synthase and produce nitric oxide in response to inflammatory cytokines and activated T cells

In this report we show that rat retinal pigment epithelial (RPE) cells express an inducible form of nitric oxide synthase (iNOS) and secrete high levels of nitric oxide (NO.) when co-cultured with activated lymphocytes. We have previously shown that cultured rat RPE cells suppress syngeneic lymphocyte proliferation, an effect attributed to prostaglandin E2 (PGE2) secretion by the RPE cells. However supernatants from such co-cultures were also found to contain high levels of nitrite (NO2-), the stable end-product of NO. synthesis. RPE cell secretion of NO. was stimulated by the cytokines interferon-gamma (IFN-gamma) and tumour necrosis factor-alpha (TNF-alpha), an effect enhanced by endotoxin [lipopolysaccharide (LPS)], reduced by the competitive inhibitor of L-arginine metabolism, NG-monomethyl-L-arginine (L-NMMA) and inhibited by cycloheximide. These effects were dose dependent. Using reverse transcription (RT)/PCR a product of 1398 bp was amplified which showed sequence identity with iNOS cloned from rat vascular smooth muscle. Northern blot analysis of total RNA extracted from rat RPE before and after cytokine stimulation showed induction of a 4.5 kb (kilobase) transcript which hybridized with a 1398 bp (base pair) polymerase chain reaction (PCR)-generated cDNA probe derived from the sequence of rat RPE cell iNOS. These results indicate RPE cells express an inducible form of nitric oxide synthase (NOS) and that high levels of NO. may be produced locally in the eye by the RPE in the presence of activated lymphocytes. Given the cytostatic and cytotoxic properties of this molecule, NO. may play an important role as an inducible mediator of immunosuppressive mechanisms within the microenvironment of the eye at the site of lymphocyte activation.

Nitric oxide production by human proximal tubular cells: a novel immunomodulatory mechanism?

It is believed that human proximal tubular cells may possess immunological function and play an important role in a variety of renal disease states such as interstitial nephritis, allograft rejection and drug induced nephrotoxicity. The role of cytokines and nitric oxide in the human forms of these disease states is not clear. In this study we examined the effect of stimulation with the cytokines IL-1 beta. TNF-alpha and IFN-gamma, individually and in combination, upon primary cultures of human proximal tubular cells. Nitric oxide production increased significantly within 24 hours following cytokine stimulation. This response was inhibited, in a dose dependent manner, by L-NMMA. PCR amplification of mRNA extracted from control and cytokine stimulated human proximal tubular cells revealed a NOS product with a > 97% homology with human hepatocyte inducible nitric oxide synthase. The results of this study clearly show that human proximal tubular cells, in primary culture, are capable of producing nitric oxide in response to an immune challenge secondary to the induction of nitric oxide synthase.

Human thyroglobulin autoantibodies of subclasses IgG2 and IgG4 bind to different epitopes on thyroglobulin

IgG autoantibodies to thyroglobulin (Tg) in the serum of patients with autoimmune thyroid disease only recognize a very limited number of epitopes, probably between four and six (Nye, Pontes De Carvalho & Roitt, 1980) on the large Tg molecule (660,000 MW), but attempts to characterize the epitopes have been unsuccessful so far (Male et al., 1985). The distribution of Tg autoantibodies between the IgG subclasses also tends to be restricted and individual patients possess characteristic 'fingerprints' of high affinity IgG1 and/or IgG4 Tg antibodies with smaller amounts of IgG2 Tg antibody (McLachlan et al., 1987, 1988). We have therefore investigated the possibility that Tg autoantibodies of different IgG subclasses interact with different epitopes on Tg.