Isolation of Salmonella spp. from Animal Feed

The isolation of Salmonella from feed is challenging and adjustments need to be made in order to accurately isolate the pathogen from feed. This is due to the complex nature of the feed matrix, which is both porous and fibrous. The outlined method below contains the essential components of a successful Salmonella methodology for the analysis of feed that overcomes the limitations of currently available methods.

Lrig1+ gastric isthmal progenitor cells restore normal gastric lineage cells during damage recovery in adult mouse stomach

OBJECTIVE

Lrig1 is a marker of proliferative and quiescent stem cells in the skin and intestine. We examined whether Lrig1-expressing cells are long-lived gastric progenitors in gastric glands in the mouse stomach. We also investigated how the Lrig1-expressing progenitor cells contribute to the regeneration of normal gastric mucosa by lineage commitment to parietal cells after acute gastric injury in mice.

DESIGN

We performed lineage labelling using Lrig1-CreERT2/+;R26R-YFP/+ (Lrig1/YFP) or R26R-LacZ/+ (Lrig1/LacZ) mice to examine whether the Lrig1-YFP-marked cells are gastric progenitor cells. We studied whether Lrig1-YFP-marked cells give rise to normal gastric lineage cells in damaged mucosa using Lrig1/YFP mice after treatment with DMP-777 to induce acute injury. We also studied Lrig1-CreERT2/CreERT2 (Lrig1 knockout) mice to examine whether the Lrig1 protein is required for regeneration of gastric corpus mucosa after acute injury.

RESULTS

Lrig1-YFP-marked cells give rise to gastric lineage epithelial cells both in the gastric corpus and antrum, in contrast to published results that Lgr5 only marks progenitor cells within the gastric antrum. Lrig1-YFP-marked cells contribute to replacement of damaged gastric oxyntic glands during the recovery phase after acute oxyntic atrophy in the gastric corpus. Lrig1 null mice recovered normally from acute gastric mucosal injury indicating that Lrig1 protein is not required for lineage differentiation. Lrig1+ isthmal progenitor cells did not contribute to transdifferentiating chief cell lineages after acute oxyntic atrophy.

CONCLUSIONS

Lrig1 marks gastric corpus epithelial progenitor cells capable of repopulating the damaged oxyntic mucosa by differentiating into normal gastric lineage cells in mouse stomach.

p120-Catenin is an obligate haploinsufficient tumor suppressor in intestinal neoplasia

p120-Catenin (p120) functions as a tumor suppressor in intestinal cancer, but the mechanism is unclear. Here, using conditional p120 knockout in Apc-sensitized mouse models of intestinal cancer, we have identified p120 as an "obligatory" haploinsufficient tumor suppressor. Whereas monoallelic loss of p120 was associated with a significant increase in tumor multiplicity, loss of both alleles was never observed in tumors from these mice. Moreover, forced ablation of the second allele did not further enhance tumorigenesis, but instead induced synthetic lethality in combination with Apc loss of heterozygosity. In tumor-derived organoid cultures, elimination of both p120 alleles resulted in caspase-3-dependent apoptosis that was blocked by inhibition of Rho kinase (ROCK). With ROCK inhibition, however, p120-ablated organoids exhibited a branching phenotype and a substantial increase in cell proliferation. Access to data from Sleeping Beauty mutagenesis screens afforded an opportunity to directly assess the tumorigenic impact of p120 haploinsufficiency relative to other candidate drivers. Remarkably, p120 ranked third among the 919 drivers identified. Cofactors α-catenin and epithelial cadherin (E-cadherin) were also among the highest scoring candidates, indicating a mechanism at the level of the intact complex that may play an important role at very early stages of of intestinal tumorigenesis while simultaneously restricting outright loss via synthetic lethality.

LRIG1 Regulates Ontogeny of Smooth Muscle-Derived Subsets of Interstitial Cells of Cajal in Mice

BACKGROUND & AIMS

Interstitial cells of Cajal (ICC) control intestinal smooth muscle contraction to regulate gut motility. ICC within the plane of the myenteric plexus (ICC-MY) arise from KIT-positive progenitor cells during mouse embryogenesis. However, little is known about the ontogeny of ICC associated with the deep muscular plexus (ICC-DMP) in the small intestine and ICC associated with the submucosal plexus (ICC-SMP) in the colon. Leucine-rich repeats and immunoglobulin-like domains protein 1 (LRIG1) marks intestinal epithelial stem cells, but the role of LRIG1 in nonepithelial intestinal cells has not been identified. We sought to determine the ontogeny of ICC-DMP and ICC-SMP, and whether LRIG1 has a role in their development.

METHODS

Lrig1-null mice (homozygous Lrig1-CreERT2) and wild-type mice were analyzed by immunofluorescence and transit assays. Transit was evaluated by passage of orally administered rhodamine B-conjugated dextran. Lrig1-CreERT2 mice or mice with CreERT2 under control of an inducible smooth muscle promoter (Myh11-CreERT2) were crossed with Rosa26-LSL-YFP mice for lineage tracing analysis.

RESULTS

In immunofluorescence assays, ICC-DMP and ICC-SMP were found to express LRIG1. Based on lineage tracing, ICC-DMP and ICC-SMP each arose from LRIG1-positive smooth muscle progenitors. In Lrig1-null mice, there was loss of staining for KIT in DMP and SMP regions, as well as for 2 additional ICC markers (anoctamin-1 and neurokinin 1 receptor). Lrig1-null mice had significant delays in small intestinal transit compared with control mice.

CONCLUSIONS

LRIG1 regulates the postnatal development of ICC-DMP and ICC-SMP from smooth muscle progenitors in mice. Slowed small intestinal transit observed in Lrig1-null mice may be due, at least in part, to loss of the ICC-DMP population.

Using a new Lrig1 reporter mouse to assess differences between two Lrig1 antibodies in the intestine

Lrig1 is an intestinal stem cell marker important for epithelial homeostasis. However, the position of the Lrig1(+) population in the intestinal crypt has been debated, largely due to discrepant staining patterns using two Lrig1 antibodies. Here, we set out to decipher the differences between these Lrig1 antibodies to clarify their use for Lrig1-related studies. We confirmed that the commercially available Lrig1-R&D antibody stained the bottom third of the colonic crypt, whereas an independently generated Lrig1-VU antibody recognized a subset of anti-Lrig1-R&D(+) cells. Biochemically, we found that anti-Lrig1-VU recognized a non-glycosylated form of Lrig1; in contrast, anti-Lrig1-R&D recognized both glycosylated and non-glycosylated forms of Lrig1. In addition, we generated a reporter mouse (Lrig1-Apple) as an independent readout of Lrig1 transcriptional activity. Flow cytometry of isolated colonic epithelial cells from Lrig1-Apple mice demonstrated anti-Lrig1-R&D recognized mostly RFP-hi cells, while anti-Lrig1-VU recognized cells that were largely RFP-mid. Of note, by qRT-PCR, Lgr5 was expressed in the RFP-hi population, but not in the RFP-mid population. We conclude that anti-Lrig1-R&D appears to recognize all Lrig1(+) cells, while anti-Lrig1-VU recognizes a subpopulation of Lrig1(+) cells.

Inducible loss of one Apc allele in Lrig1-expressing progenitor cells results in multiple distal colonic tumors with features of familial adenomatous polyposis

Individuals with familial adenomatous polyposis (FAP) harbor a germline mutation in adenomatous polyposis coli (APC). The major clinical manifestation is development of multiple colonic tumors at a young age due to stochastic loss of the remaining APC allele. Extracolonic features, including periampullary tumors, gastric abnormalities, and congenital hypertrophy of the retinal pigment epithelium, may occur. The objective of this study was to develop a mouse model that simulates these features of FAP. We combined our Lrig1-CreERT2/+ mice with Apcfl/+ mice, eliminated one copy of Apc in leucine-rich repeats and immunoglobulin-like domains protein 1 (Lrig1)-positive (Lrig1(+)) progenitor cells with tamoxifen injection, and monitored tumor formation in the colon by colonoscopy and PET. Initial loss of one Apc allele in Lrig1(+) cells results in a predictable pattern of preneoplastic changes, culminating in multiple distal colonic tumors within 50 days of induction, as well as the extracolonic manifestations of FAP mentioned above. We show that tumor formation can be monitored by noninvasive PET imaging. This inducible stem cell-driven model recapitulates features of FAP and offers a tractable platform on which therapeutic interventions can be monitored over time by colonoscopy and noninvasive imaging.

Excess PLAC8 promotes an unconventional ERK2-dependent EMT in colon cancer

The epithelial-to-mesenchymal transition (EMT) transcriptional program is characterized by repression of E-cadherin (CDH1) and induction of N-cadherin (CDH2), and mesenchymal genes like vimentin (VIM). Placenta-specific 8 (PLAC8) has been implicated in colon cancer; however, how PLAC8 contributes to disease is unknown, and endogenous PLAC8 protein has not been studied. We analyzed zebrafish and human tissues and found that endogenous PLAC8 localizes to the apical domain of differentiated intestinal epithelium. Colon cancer cells with elevated PLAC8 levels exhibited EMT features, including increased expression of VIM and zinc finger E-box binding homeobox 1 (ZEB1), aberrant cell motility, and increased invasiveness. In contrast to classical EMT, PLAC8 overexpression reduced cell surface CDH1 and upregulated P-cadherin (CDH3) without affecting CDH2 expression. PLAC8-induced EMT was linked to increased phosphorylated ERK2 (p-ERK2), and ERK2 knockdown restored cell surface CDH1 and suppressed CDH3, VIM, and ZEB1 upregulation. In vitro, PLAC8 directly bound and inactivated the ERK2 phosphatase DUSP6, thereby increasing p-ERK2. In a murine xenograft model, knockdown of endogenous PLAC8 in colon cancer cells resulted in smaller tumors, reduced local invasion, and decreased p-ERK2. Using MultiOmyx, a multiplex immunofluorescence-based methodology, we observed coexpression of cytosolic PLAC8, CDH3, and VIM at the leading edge of a human colorectal tumor, supporting a role for PLAC8 in cancer invasion in vivo.

Pathology of rodent models of intestinal cancer: progress report and recommendations

In October 2010, a pathology review of rodent models of intestinal neoplasia was held at The Jackson Laboratory. This review complemented 2 other concurrent events: a workshop on methods of modeling colon cancer in rodents and a conference on current issues in murine and human colon cancer. We summarize the results of the pathology review and the committee's recommendations for tumor nomenclature. A virtual high-resolution image slide box of these models has been developed. This report discusses significant recent developments in rodent modeling of intestinal neoplasia, including the role of stem cells in cancer and the creation of models of metastatic intestinal cancer.

Helicobacter pylori promotes the expression of Krüppel-like factor 5, a mediator of carcinogenesis, in vitro and in vivo

Helicobacter pylori is the strongest known risk factor for the development of gastric adenocarcinoma. H. pylori expresses a repertoire of virulence factors that increase gastric cancer risk, including the cag pathogenicity island and the vacuolating cytotoxin (VacA). One host element that promotes carcinogenesis within the gastrointestinal tract is Krüppel-like factor 5 (KLF5), a transcription factor that mediates key cellular functions. To define the role of KLF5 within the context of H. pylori-induced inflammation and injury, human gastric epithelial cells were co-cultured with the wild-type cag⁺ H. pylori strain 60190. KLF5 expression was significantly upregulated following co-culture with H. pylori, but increased expression was independent of the cag island or VacA. To translate these findings into an in vivo model, C57BL/6 mice were challenged with the wild-type rodent-adapted cag⁺ H. pylori strain PMSS1 or a PMSS1 cagE⁻ isogenic mutant. Similar to findings in vitro, KLF5 staining was significantly enhanced in gastric epithelium of H. pylori-infected compared to uninfected mice and this was independent of the cag island. Flow cytometry revealed that the majority of KLF5⁺ cells also stained positively for the stem cell marker, Lrig1, and KLF5⁺/Lrig1⁺ cells were significantly increased in H. pylori-infected versus uninfected tissue. To extend these results into the natural niche of this pathogen, levels of KLF5 expression were assessed in human gastric biopsies isolated from patients with or without premalignant lesions. Levels of KLF5 expression increased in parallel with advancing stages of neoplastic progression, being significantly elevated in gastritis, intestinal metaplasia, and dysplasia compared to normal gastric tissue. These results indicate that H. pylori induces expression of KLF5 in gastric epithelial cells in vitro and in vivo, and that the degree of KLF5 expression parallels the severity of premalignant lesions in human gastric carcinogenesis.

The pan-ErbB negative regulator Lrig1 is an intestinal stem cell marker that functions as a tumor suppressor

Lineage mapping has identified both proliferative and quiescent intestinal stem cells, but the molecular circuitry controlling stem cell quiescence is incompletely understood. By lineage mapping, we show Lrig1, a pan-ErbB inhibitor, marks predominately noncycling, long-lived stem cells that are located at the crypt base and that, upon injury, proliferate and divide to replenish damaged crypts. Transcriptome profiling of Lrig1(+) colonic stem cells differs markedly from the profiling of highly proliferative, Lgr5(+) colonic stem cells; genes upregulated in the Lrig1(+) population include those involved in cell cycle repression and response to oxidative damage. Loss of Apc in Lrig1(+) cells leads to intestinal adenomas, and genetic ablation of Lrig1 results in heightened ErbB1-3 expression and duodenal adenomas. These results shed light on the relationship between proliferative and quiescent intestinal stem cells and support a model in which intestinal stem cell quiescence is maintained by calibrated ErbB signaling with loss of a negative regulator predisposing to neoplasia.

Abstract 5188: Lrig1, a cell surface negative regulator of ErbB1-4, marks both proliferative and quiescent intestinal stem cells and acts as a tumor suppressor

Whether proliferative and quiescent intestinal stem cells coexist in normal and cancerous tissue is controversial. Due to heightened transcript expression in the intestinal epithelial stem cell compartment, detection in quiescent hair follicle stem cells and frequent loss in breast cancer, we hypothesized that Leucine-rich repeats and immunoglobulin-like domain protein 1 (Lrig1) would mark a novel population of intestinal stem cells and may be important for intestinal homeostasis and in cancer. To study this, we generated Lrig1-CreERT2/+; R26R-LacZ mice to study the role of Lrig1. One day after Lrig1-CreERT2/+; R26R-LacZ mice received a single injection of tamoxifen, 1-2 cells were labeled in the progenitor zone. Three months after injection, 10% of colonic crypts were entirely labeled and 8% of crypts contained singly labeled, non-proliferative, Lgr5-negative cells at the crypt-base. In a regenerative response to gut injury, these singly labeled cells proliferated and gave rise to clusters of labeled daughter cells, demonstrating the ability of these quiescent stem cells to become activated. Loss of Lrig1 resulted in heightened expression of ErbB1-3 in the normal intestine, duodenal adenomas and carcinoma, supporting a functional role for Lrig1 in the maintenance of intestinal epithelial homeostasis and its ability to act as a tumor suppressor. In addition, driving stochastic loss of Apc in Lrig1-expressing cells results in multiple, large distal colonic tumors and less frequent, smaller intestinal tumors, which are common features of human familial polyposis. In summary, we show that Lrig1, a cell surface negative regulator of ErbB1-4, marks both proliferative and quiescent intestinal stem cells and acts as a tumor suppressor.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr 5188. doi:10.1158/1538-7445.AM2011-5188

Fusion between Intestinal epithelial cells and macrophages in a cancer context results in nuclear reprogramming

The most deadly phase in cancer progression is attributed to the inappropriate acquisition of molecular machinery leading to metastatic transformation and spread of disease to distant organs. Although it is appreciated that metastasis involves epithelial-mesenchymal interplay, the underlying mechanism defining this process is poorly understood. Specifically, how cancer cells evade immune surveillance and gain the ability to navigate the circulatory system remains a focus. One possible mechanism underlying metastatic conversion is fusion between blood-derived immune cells and cancer cells. While this notion is a century old, in vivo evidence that cell fusion occurs within tumors and imparts genetic or physiologic changes remains controversial. We have previously demonstrated in vivo cell fusion between blood cells and intestinal epithelial cells in an injury setting. Here, we hypothesize that immune cells, such as macrophages, fuse with tumor cells imparting metastatic capabilities by transferring their cellular identity. We used parabiosis to introduce fluorescent-labeled bone marrow-derived cells to mice with intestinal tumors, finding that fusion between circulating blood-derived cells and tumor epithelium occurs during the natural course of tumorigenesis. Moreover, we identify the macrophage as a key cellular partner for this process. Interestingly, cell fusion hybrids retain a transcriptome identity characteristic of both parental derivatives, while also expressing a unique subset of transcripts. Our data supports the novel possibility that tumorigenic cell fusion may impart physical behavior attributed to migratory macrophages, including navigation of circulation and immune evasion. As such, cell fusion may represent a promising novel mechanism underlying the metastatic conversion of cancer cells.

Characterization of the intestinal cancer stem cell marker CD166 in the human and mouse gastrointestinal tract

BACKGROUND & AIMS

CD166 (also called activated leukocyte cell adhesion molecule [ALCAM]) is a marker of colorectal cancer (CRC) stem cells; it is expressed by aggressive tumors. Although the presence of CD166 at the tumor cell surface has been correlated with shortened survival, little is known about its function and expression in normal intestinal epithelia.

METHODS

We characterized the expression pattern of CD166 in normal intestinal tissue samples from humans and mice using immunohistochemisty, flow cytometry, and quantitative reverse-transcriptase polymerase chain reaction. Human and mouse intestinal tumors were also analyzed.

RESULTS

CD166 was expressed on the surface of epithelial cells within the stem cell niche and along the length of the intestine; expression was conserved across species. In the small intestine, CD166 was observed on crypt-based Paneth cells and intervening crypt-based columnar cells (putative stem cells). A subset of CD166-positive, crypt-based columnar cells coexpressed the stem cell markers Lgr5, Musashi-1, or Dcamkl-1. CD166 was located in the cytoplasm and at the surface of cells within human CRC tumors. CD166-positive cells were also detected in benign adenomas in mice; rare cells coexpressed CD166 and CD44 or epithelial-specific antigen.

CONCLUSIONS

CD166 is highly expressed within the endogenous intestinal stem cell niche. CD166-positive cells appear at multiple stages of intestinal carcinoma progression, including benign and metastatic tumors. Further studies should investigate the function of CD166 in stem cells and the stem cell niche, which might have implications for normal intestinal homeostasis. CD166 has potential as a therapeutic target for CRC.

Lessons from development: A role for asymmetric stem cell division in cancer

Asymmetric stem cell division has emerged as a major regulatory mechanism for physiologic control of stem cell numbers. Reinvigoration of the cancer stem cell theory suggests that tumorigenesis may be regulated by maintaining the balance between asymmetric and symmetric cell division. Therefore, mutations affecting this balance could result in aberrant expansion of stem cells. Although a number of molecules have been implicated in regulation of asymmetric stem cell division, here, we highlight known tumor suppressors with established roles in this process. While a subset of these tumor suppressors were originally defined in developmental contexts, recent investigations reveal they are also lost or mutated in human cancers. Mutations in tumor suppressors involved in asymmetric stem cell division provide mechanisms by which cancer stem cells can hyperproliferate and offer an intriguing new focus for understanding cancer biology. Our discussion of this emerging research area derives insight from a frontier area of basic science and links these discoveries to human tumorigenesis. This highlights an important new focus for understanding the mechanism underlying expansion of cancer stem cells in driving tumorigenesis.

Inflammation and proliferation act together to mediate intestinal cell fusion

Cell fusion between circulating bone marrow-derived cells (BMDCs) and non-hematopoietic cells is well documented in various tissues and has recently been suggested to occur in response to injury. Here we illustrate that inflammation within the intestine enhanced the level of BMDC fusion with intestinal progenitors. To identify important microenvironmental factors mediating intestinal epithelial cell fusion, we performed bone marrow transplantation into mouse models of inflammation and stimulated epithelial proliferation. Interestingly, in a non-injury model or in instances where inflammation was suppressed, an appreciable baseline level of fusion persisted. This suggests that additional mediators of cell fusion exist. A rigorous temporal analysis of early post-transplantation cellular dynamics revealed that GFP-expressing donor cells first trafficked to the intestine coincident with a striking increase in epithelial proliferation, advocating for a required fusogenic state of the host partner. Directly supporting this hypothesis, induction of augmented epithelial proliferation resulted in a significant increase in intestinal cell fusion. Here we report that intestinal inflammation and epithelial proliferation act together to promote cell fusion. While the physiologic impact of cell fusion is not yet known, the increased incidence in an inflammatory and proliferative microenvironment suggests a potential role for cell fusion in mediating the progression of intestinal inflammatory diseases and cancer.

Understanding the challenges of service change - learning from acute pain services in the UK

OBJECTIVES

To explore organizational difficulties faced when implementing national policy recommendations in local contexts.

DESIGN

Qualitative case study involving semi-structured interviews with health professionals and managers working in and around acute pain services.

SETTING

Three UK acute hospital organizations.

MAIN OUTCOME MEASURES

Identification of the content, context and process factors impacting on the implementation of the national policy recommendations on acute pain services; insights into and deeper understanding of the generic obstacles to change facing service improvements.

RESULTS

The process of implementing policy recommendations and improving services in each of the three organizations was undermined by multiple factors relating to: doubts and disagreements about the nature of the change; challenging local organizational contexts; and the beliefs, attitudes and responses of health professionals and managers. The impact of these factors was compounded by the interaction between them.

CONCLUSIONS

Local implementation of national policies aimed at service improvement can be undermined by multiple interacting factors. Particularly important are the pre-existing local organizational contexts and histories, and the deeply-ingrained attitudes, beliefs and assumptions of diverse staff groups. Without close attention to all of these underlying issues and how they interact in individual organizations against the background of local and national contexts, more resources or further structural change are unlikely to deliver the intended improvements in patient care.

Wnt-reporter expression pattern in the mouse intestine during homeostasis

Background

The canonical Wnt signaling pathway is a known regulator of cell proliferation during development and maintenance of the intestinal epithelium. Perturbations in this pathway lead to aberrant epithelial proliferation and intestinal cancer. In the mature intestine, proliferation is confined to the relatively quiescent stem cells and the rapidly cycling transient-amplifying cells in the intestinal crypts. Although the Wnt signal is believed to regulate all proliferating intestinal cells, surprisingly, this has not been thoroughly demonstrated. This important determination has implications on intestinal function, especially during epithelial expansion and regeneration, and warrants an extensive characterization of Wnt-activated cells.

Methods

To identify intestinal epithelial cells that actively receive a Wnt signal, we analyzed intestinal Wnt-reporter expression patterns in two different mouse lines using immunohistochemistry, enzymatic activity, in situ hybridization and qRT-PCR, then corroborated results with reporter-independent analyses. Wnt-receiving cells were further characterized for co-expression of proliferation markers, putative stem cell markers and cellular differentiation markers using an immunohistochemical approach. Finally, to demonstrate that Wnt-reporter mice have utility in detecting perturbations in intestinal Wnt signaling, the reporter response to gamma-irradiation was examined.

Results

Wnt-activated cells were primarily restricted to the base of the small intestinal and colonic crypts, and were highest in numbers in the proximal small intestine, decreasing in frequency in a gradient toward the large intestine. Interestingly, the majority of the Wnt-reporter-expressing cells did not overlap with the transient-amplifying cell population. Further, while Wnt-activated cells expressed the putative stem cell marker Musashi-1, they did not co-express DCAMKL-1 or cell differentiation markers. Finally, gamma-irradiation stimulated an increase in Wnt-activated intestinal crypt cells.

Conclusion

We show, for the first time, detailed characterization of the intestine from Wnt-reporter mice. Further, our data show that the majority of Wnt-receiving cells reside in the stem cell niche of the crypt base and do not extend into the proliferative transient-amplifying cell population. We also show that the Wnt-reporter mice can be used to detect changes in intestinal epithelial Wnt signaling upon physiologic injury. Our findings have an important impact on understanding the regulation of the intestinal stem cell hierarchy during homeostasis and in disease states.

Exploring the relationship between senior management team culture and hospital performance

The purpose of this study was to explore relationships between senior management team culture and organizational performance in English hospital organizations (NHS trusts [National Health Service]). We used an established culture-rating instrument, the Competing Values Framework, to assess senior management team culture. Organizational performance was assessed using a wide variety of routinely collected measures. Data were gathered from all English NHS acute hospital trusts, a total of 197 organizations. Multivariate econometric analyses were used to explore the associations between measures of culture and measures of performance using regressions, ANOVA, multinomial logit, and ordered probit. Organizational culture varied across hospital organizations, and at least some of this variation was associated in consistent and predictable ways with a variety of organizational characteristics and measures of performance. The findings provide particular support for a contingent relationship between culture and performance.

Rhetoric and reality on acute pain services in the UK: a national postal questionnaire survey

BACKGROUND

The study aimed to explore the extent to which NHS acute pain services (APSs) have been established in accordance with national guidance, and to assess the degree to which clinicians in acute pain management believe that these services are fulfilling their role.

METHODS

A postal questionnaire survey addressed to the head of the acute pain service was sent to 403 National Health Service hospitals each carrying out more than 1000 operative procedures a year.

RESULTS

Completed questionnaires were received from 81% (325) of the hospitals, of which 83% (270) had an established acute pain service. Most of these (86%) described their service as Monday-Friday with a reduced service at other times; only 5% described their service as covering 24 hours, 7 days a week. In the majority of hospitals (68%), the on-call anaesthetist was the sole provider of out of hours services. Services were categorized by respondents as thriving (30%), struggling to manage (52%) or non-existent (17%). There was widespread agreement (> or =85%) on the principles that should underpin acute pain services, and similar agreement on the need for better organizational approaches (95%) rather than new treatments and delivery techniques (19%).

CONCLUSIONS

More than a decade since the 1990 report Pain after Surgery, national coverage of comprehensive acute pain services is still far from being achieved. Despite wide consensus about the problems, concrete solutions are proving hard to implement. There is strong support for a two-fold response: securing greater political commitment to pain services and using organizational approaches to address current deficits.

Using routine comparative data to assess the quality of health care: understanding and avoiding common pitfalls

Measuring the quality of health care has become a major concern for funders and providers of health services in recent decades. One of the ways in which quality of care is currently assessed is by taking routinely collected data and analysing them quantitatively. The use of routine data has many advantages but there are also some important pitfalls. Collating numerical data in this way means that comparisons can be made--whether over time, with benchmarks, or with other healthcare providers (at individual or institutional levels of aggregation). Inevitably, such comparisons reveal variations. The natural inclination is then to assume that such variations imply rankings: that the measures reflect quality and that variations in the measures reflect variations in quality. This paper identifies reasons why these assumptions need to be applied with care, and illustrates the pitfalls with examples from recent empirical work. It is intended to guide not only those who wish to interpret comparative quality data, but also those who wish to develop systems for such analyses themselves.

Nucleoside transporter subtype expression: effects on potency of adenosine kinase inhibitors

1. Adenosine kinase (AK) inhibitors can enhance adenosine levels and potentiate adenosine receptor activation. As the AK inhibitors 5' iodotubercidin (ITU) and 5-amino-5'-deoxyadenosine (NH(2)dAdo) are nucleoside analogues, we hypothesized that nucleoside transporter subtype expression can affect the potency of these inhibitors in intact cells. 3. Three nucleoside transporter subtypes that mediate adenosine permeation of rat cells have been characterized and cloned: equilibrative transporters rENT1 and rENT2 and concentrative transporter rCNT2. We stably transfected rat C6 glioma cells, which express rENT2 nucleoside transporters, with rENT1 (rENT1-C6 cells) or rCNT2 (rCNT2-C6 cells) nucleoside transporters. 3. We tested the effects of ITU and NH(2)dAdo on [(3)H]-adenosine uptake and conversion to [(3)H]-adenine nucleotides in the three cell types. NH(2)dAdo did not show any cell type selectivity. In contrast, ITU showed significant inhibition of [(3)H]-adenosine uptake and [(3)H]-adenine nucleotide formation at concentrations < or =100 nM in rENT1-C6 cells, while concentrations > or =3 microM were required for C6 or rCNT2-C6 cells. 4. Nitrobenzylthioinosine (NBMPR; 100 nM), a selective inhibitor of rENT1, abolished the effects of nanomolar concentrations of ITU in rENT1-C6 cells. 5. This study demonstrates that the effects of ITU, but not NH(2)dAdo, in whole cell assays are dependent upon nucleoside transporter subtype expression. Thus, cellular and tissue differences in expression of nucleoside transporter subtypes may affect the pharmacological actions of some AK inhibitors.

Reading and assessing qualitative research

What makes doctors burn out? What is it like to have epilepsy? Why do smokers not give up? Qualitative research makes it possible to look behind the statistics and to study health and health care from the inside: to find out what it is really like for the health professionals who provide the care and for the patients on the receiving end.

Variation of resorption rates in vivo of various bones in immature rats

The 3H-tetracycline method of measuring bone resorption in vivo was applied to the comparison of various whole bones in rats of two different ages. The rat was chosen because it grows via modelling processes and contains little, if any, cortical remodelling except for a small amount of trabecular remodelling. It was found that resorption rates in vivo are high and similar in almost all of the 18 bones measured between birth and 2 weeks of age. However, in weanling rats studied at 4-6 weeks of age, resorption rates in the skull and in the long bones had decreased significantly while remaining high in the vertebrae, scapula, sternum and pelvis. Bones of neonatal rats were quite alike in their rates of bone resorption, but the bones of the weanlings manifested significant heterogeneity in their rates. It is known that anatomic heterogeneity of metabolic turnover of various bones characterizes the mature state in humans and dogs as well. The present data are unique in that they reflect absolute resorption rates in vivo uncomplicated by the extensive re-utilization of calcium inherent in other isotopic or non-isotopic protocols.

Biology of cancellous bone grafts

Despite 30 years of experimental bone grafting research, the fresh cancellous bone graft remains the most osteogenic and reliable bone grafting material. Recent experimental data suggest that modification of the graft-host interaction by antigen matching or immune manipulation may allow increasingly successful use of allografts.

The long-term fate of fresh and frozen orthotopic bone allografts in genetically defined rats

Fresh and frozen orthotopic iliac crest bone grafts in rats were studied histologically for determination of the long-term effects of histocompatibility matching and the freezing process on orthotopic bone graft incorporation. Grafts exchanged between groups of inbred rats, syngeneic or differing with respect to major or minor histocompatibility loci, were studied histologically at 20, 30, 40, 50, and 150 days after bone transplantation. A numerical histologic scoring system was developed and used by three observers for evaluation of coded hematoxylin and eosin sections. All frozen graft groups had the same fate regardless of histocompatibility relations between donors and recipients, and all grafts were inferior to fresh syngeneic grafts. Both fresh allograft groups received similar scores and initially at 20 and 30 days had scores similar to those of the fresh syngeneic groups. In the later intervals, however, the fresh allografts were inferior to the fresh syngeneic grafts and similar to the frozen groups. This is consistent with an older model describing two distinct phases of osteogenesis. In the long term, frozen syngeneic and fresh and frozen allografts across major and minor histocompatibility barriers were comparable, but all were significantly inferior to fresh syngeneic bone grafts.

Effects on bone of vascular interruption. Turnover and morphology in isotope-prelabelled rats

The effects of bone devascularization were evaluated histologically and metabolically in rats prelabelled with 45Ca, 3H-tetracycline and 3H-proline by quantifying cortical bone resorption and formation. The interruption of blood supply to bone without invading its integrity resulted in a marked increase in bone turnover (resorption and formation) during the first and second months. The stimulated increase in bone resorption and formation did not affect the resultant mass of collagen and calcium. Thus, the increase in bone resorption was compensated by an equivalent increase in bone formation.

Improved acceptance of frozen bone allografts in genetically mismatched dogs by immunosuppression

We studied the role of immunosuppressive therapy in improving the incorporation of frozen bone allografts exchanged across strong transplantation barriers in a canine cancellous ulnar segmental replacement model. Dogs receiving frozen bone from donors with major histocompatibility differences received one of three different immunosuppressive treatments. In two groups, azathioprine and prednisolone were administered for either twenty-eight or fifty-six days; anti-lymphocyte globulin was added for another twenty-eight-day group in a third regimen. Frozen bone was evaluated radiographically and histologically by criteria that quantified the biological characteristics of the bone itself and union between the graft and host at thirteen and twenty-six weeks after grafting. Graft incorporation in these animals was compared with graft acceptance in a similar group of untreated animals and in untreated animals in which bone was exchanged across weak transplantation barriers. Complications of immunosuppression included wound drainage, infection, weight loss, and falling white-blood-cell counts. Seven of the original thirty-seven animals died as a direct result of these complications. After twenty-six weeks the grafts in the recipients receiving immunosuppression appeared radiographically and histologically indistinguishable from those in the untreated, genetically closely matched group and from autografts. They were significantly better incorporated than identical allografts placed in untreated, genetically disparate recipients. There was no difference in the effectiveness of any of the immunosuppressive programs.

CLINICAL RELEVANCE

Immunosuppression improves the biological outcome of otherwise poorly performing frozen bone allografts in dogs. This finding suggests that treatments that modify the immunological response of the host without major side effects may be useful clinically in improving the success of massive frozen bone allografts.

The effect of histocompatibility matching on canine frozen bone allografts

The value of histocompatibility matching in frozen bone allografts was studied in a canine cancellous ulnar segmental-replacement model. Frozen bone that was exchanged across strong and weak transplantation barriers was evaluated histologically and radiographically at thirteen and twenty-six weeks after grafting. Histological grading criteria quantified the type of union at each end of the graft and the degree of remodeling of the marrow, spongiosa, and compacta. Radiographic grading criteria included the presence of union at each end of the graft and the degree of remodeling of the graft segment. In vitro studies for serum antibody and cell-mediated immunity were carried out by isotopic cytotoxicity methods at seven intervals during the twenty-six-week study period. Histologically, the strong-barrier allografts had fewer osseous unions and less reorganization of spongiosa and marrow when compared with autograft controls at both thirteen and twenty-six weeks. Radiographically, the strong-barrier allografts at thirteen weeks had fewer unions and marked resorption of grafts material when compared with autograft controls. There were no differences between weak transplantation-barrier grafts and control autografts radiographically or histologically at thirteen and twenty-six weeks after grafting. Frozen bone allografts did not elicit detectable serum antibody or lymphocytes that were cytotoxic for donor cells.

Cell populations in leucocyte adherence inhibition: requirement for T lymphocytes with IgG Fc receptors

The subset identity of T lymphocytes participating in the leucocyte adherence inhibition (LAI) reaction was investigated. Humans were immunized with keyhole limpet haemocyanin (KLH) and their cellular immunity was tested by means of the haemocytometer variant of the LAI method. Their lymphocytes were fractionated by rosetting methods employing neuraminidase-treated sheep erythrocytes and IgG- or IgM-coated ox erythrocytes. The T lymphocytes rosetted by IgG-coated ox cells (T gamma) reacted with KLH to give specific LAI reactions. Non-T gamma cells failed to react. The T gamma cells released a lymphokine which caused an LAI reaction of T lymphocytes from non-immunized donors. Immune non-T gamma cells, when incubated with KLH yielded inactive supernates. The normal cells which gave positive LAI responses to the lymphokine also proved to belong exclusively to the T gamma subclass. Cells positively selected with IgM-coated ox cells (T micro) were inactive while the non-T micro lymphocytes behaved like the T gamma cells. It was shown that the activity was confined to the T gamma subset throughout the time course of a primary immune response. Thus, LAI reactivity appears to be a property of a very small subclass of lymphocytes which communicate with each other by means of a soluble factor.

Leukocyte-adherence inhibition: a specific assay of cell-mediated immunity dependent on lymphokine-mediated collaboration between T lymphocytes

The leukocyte-adherence inhibition (LAI) assay was studied to determine its immunologic relevance and identify the cell populations on which it depends. Two systems were employed: peripheral blood leukocytes from humans immunized with KLH, and lymph node cells from rats immunized with DNP-BCG. In both cases, LAI responses appeared about 3 to 4 days after immunization, reached a peak about 3 to 4 weeks later, and diminished thereafter. Reimmunization resulted in a booster-like response. LAI analysis in both systems showed dose-response dependency. Responses could be elicited only with the immunizing antigen. Virtual depletion of phagocytic cells had no effect on the response. E-rosette-forming cells gave an excellent response to KLH and also produced an active supernatant (lymphokine). Cells not forming spontaneous E-rosettes were inactive and could not produce active supernatants. Only those nonimmune cells that formed E-rosettes could respond to active supernatants. Thus, the LAI response is a specific indicator of cell-mediated immunity. T lymphocytes probably are required both at the antigen-reactive stage and at the stage of responding to the T cell-dependent lymphokine.

The adoptive transfer of pregnancy-induced unresponsiveness to male skin grafts with thymus-dependent cells

A majority of C57BL/10Sn females pregnant six or more times by syngeneic males do not reject male skin grafts. The pregnancy induced tolerance of male skin grafts was transferred adoptively to virgin recipients by thymus-dependent cells from multiparous tolerant donors.

Specific responsiveness of leukocytes to soluble extracts of human tumors

The leukocyte adherence inhibition (LAI) method was studied with respect to its specificity in detecting responses to extracts of tumor tissues or normal lymphocytes. Responses of cells from normal persons were within 10% of each other whether incubation was carried out with culture medium alone or with any of the extracts. The same was true of cells from 78 cancer patients unless the cells were incubated with extracts of the same histologic type as their own. In the latter case, statistically significant responses occurred in 95% of the 110 analyses done. Negative responses were given by cells from 14 patients tentatively diagnosed as having breast carcinoma but whose lesions later proved benign. There was one positive response inconsistent with the diagnosis. Of 29 normal individuals known to have been exposed to tumors or tumor extracts, 11 responded positively and specifically to the relevant tumor extract. Cells from 12 of 30 multiparous female breast-cancer patients responded to extracts of pooled normal lymphocytes. The results establish that the LAI analysis is an extremely specific means of detecting systemic responses to malignant diseases. In addition, analyses have proven positive in 95% of the cases studied.

Modulation of lymphocytic responses by factors in human plasma. I. The effects on normal, stimulated lymphocytes of various normal plasmas in microplate culture

Mitogen-induced blast transformation of human peripheral blood lymphocytes was studied using a microplate culture technique. Cells and plasmas from normal individuals were interchanged to that sources of variation in the degree of transformation could be evaluated. Also evaluated was the normal range of plasma effects. It was found that the cells of different individuals vary considerably in their responses to mitogens in a given plasma, but the hierarchy of responses is fairly consistent from plasma to plasma. Furthermore, plasmas vary from donor to donor, but also settle into a fairly consistent hierarchy regardless of the cells employed. Finally, new hierarchies are established when materials from the same donors are collected after an interval of a week. It was shown that special, nonrandom interactions may occur which are not attributable simply to the average response of a given cell and the average response to the plasma used. The range of variation to be expected in a normal system, established here, should permit comparison of plasma effects in a more interpretable framework than previously was possible.

Immunologic differentiation of classic hemophilia (factor 8 deficiency) and von Willebrand's dissase, with observations on combined deficiencies of antihemophilic factor and proaccelerin (factor V) and on an acquired circulating anticoagulant against antihemophilic factor

Heterologous antiserum was prepared in rabbits against highly purified human antihemophilic factor (AHF, factor VIII). This antiserum blocked the clot-promoting properties of AHF and, when suitably absorbed, formed a single precipitin line against AHF upon immunoelectrophoresis. Material antigenically similar to normal AHF was detected in normal amounts in plasma concentrates in each of 22 patients with classic hemophilia, in a patient with an acquired circulating anticoagulant against AHF, and in a patient with deficiencies both of AHF and proaccelerin (factor V). AHF-like antigen was present in normal human serum. In contrast, material antigenically related to AHF was found in decreased amounts in the concentrates prepared from the plasma of 11 patients with von Willebrand's disease. The experiments described suggest that von Willebrand's disease is a disorder in which a true deficiency of AHF exists. Whether the AHF-like material found in classic hemophilia is nonfunctional through a defect in structure or through the intervention of an inhibitor has not been shown.