[Adhesive capsulitis]

BACKGROUND

Adhesive capsulitis (CA; also called Frozen shoulder) is a common, usually unilateral disease of the shoulder joint primarily affecting middle-aged women. Primary, idiopathic, and secondary forms are distinguished. Painful active and passive movement restriction are the clinically leading symptoms.

COURSE OF THE DISEASE

The disease usually progresses in three successive stages: freezing phase, frozen phase, and thawing phase.

CLINICAL DIAGNOSIS AND IMAGING

CA is primarily diagnosed clinically, with imaging being used to assess or exclude differential diagnoses. Radiography as part of basic diagnostics allows exclusion of common differential diagnoses such as osteoarthritis of the shoulder or calcific tendinitis. Native magnetic resonance imaging (MRI) and MR arthrography (MRA) reveal pathomorphologies typical of CA. Intravenously administered gadolinium increases the sensitivity of MRI. Sonography may be used as a complementary diagnostic modality or as an alternative in case of contraindications to MRI. Fluoroscopy-guided arthrography has been replaced by MRI because of its invasiveness. Computed tomography (CT) has no role in diagnostics due to its radiation exposure and significantly lower sensitivity and specificity compared to MRI.

TREATMENT

Therapy of CA is stage-adapted and includes conservative measures such as analgesics and physiotherapy and surgical procedures such as arthroscopic arthrolysis. The therapeutic spectrum is supplemented by new, innovative procedures such as transarterial periarticular embolization.

PROGNOSIS

CA is self-limiting and usually persists for 2-3 years. However, the patients may even suffer from pain and limited range of motion beyond this time.

Are Population-Level Approaches to Dementia Risk Reduction Under-Researched? A Rapid Review of the Dementia Prevention Literature

Dementia is forecast to become increasingly prevalent, particularly in low- and middle-income countries, and is associated with high human and economic costs. Primary prevention of dementia -preventing risk factors leading to disease development - is an emerging global public health priority. Primary prevention can be achieved in two ways: individual-level or population-level. In this rapid review, we quantify the proportion of contributing interventional evidence to the dementia primary prevention literature that is concerned with either approach. We searched Medline, the National Institute for Health and Care Excellence, Cochrane, the World Health Organization, and Google to identify systematic reviews that described primary prevention interventions for dementia. We used search terms related to dementia risk reduction, intervention/policy, and review. We analysed reference lists of included dementia prevention reviews to identify contributing primary prevention evidence, and categorised these as either individual-level or population-level. Additionally, we examined search strategies to investigate the likelihood of reviews identifying available population-level interventions. We included twelve of the 527 articles retrieved. Population-level evidence was summarised by only two reviews. In these two reviews, <2.5% of the interventions described where population-level interventions. Most search strategies were weighted towards identifying individual-level evidence. Existing systematic reviews of dementia primary prevention interventions include almost no population-level evidence. Correction of this imbalance is needed to ensure that dementia prevention policies can achieve meaningful reductions in the prevalence of, and inequalities in, dementia.

Impact of postoperative baseline MRI on diagnostic confidence and performance in detecting local recurrence of soft-tissue sarcoma of the limb

OBJECTIVE

To evaluate the impact of a postoperative baseline (PB) MRI on diagnostic confidence and performance in detecting local recurrence (LR) of soft-tissue sarcoma (STS) of the limb.

MATERIALS AND METHODS

A total of 72 patients (8 with LR, 64 without LR) with primary STS of the limb were included. Routine follow-up MRI (1.5 T) at 6 and approximately 36 months (meanLR: 39.7 months; meanno LR: 34.9 months) after multimodal therapy or at time of LR were assessed by three independent readers using a 5-point Likert scale. Furthermore, the following imaging parameters were evaluated: presence of a mass, signal characteristics at T2- and T1-weighted imaging, contrast enhancement (CE), and in some of the cases signal intensity on the apparent diffusion coefficient (ADC). U-test, McNemar test, and ROC-analysis were applied. Interobserver reliability was calculated using Fleiss kappa statistics. A p value of 0.05 was considered statistically significant.

RESULTS

The presence of a PB MRI significantly improved diagnostic confidence in detecting LR of STS (p < 0.001) and slightly increased specificity (mean specificity without PE 74.1% and with presence of PB MRI 81.2%); however, not to a significant level. The presence of a mass showed highest diagnostic performance and highest interreader agreement (AUC [%]; κ: 73.1-83.6; 0.34) followed by T2-hyperintensity (50.8-66.7; 0.08), CE (52.4-62.5; 0.13), and T1-hypointensity (54.7-77.3; 0.23). ADC showed an AUC of 65.6-96.6% and a κ of 0.55.

CONCLUSION

The presence of a PB MRI increases diagnostic confidence in detecting LR of STS of the limb.

The Clinical Presentation of Endometriosis and Its Association to Current Surgical Staging

(1) Despite its high prevalence, the diagnostic delay of endometriosis is still estimated to be about 7 years. The objective of the present study is to understand the symptomatology of endometriosis in patients across various countries and to assess whether the severity of symptoms correlates with the diagnosed stage of disease. (2) An international online survey collected self-reported responses from 2964 participants from 59 countries. Finalization of the questionnaire and its distribution was achieved by cooperation with various organizations and centers around the globe. (3) Chronic pain presentation remarkably increased between Stage 1 and 2 (16.2% and 32.2%, respectively). The prevalence of pain only around and during menstruation was negatively correlated to the stage, presenting with 15.4% and 6.9% in Stages 1 and 4, respectively. Atypical presentation of pain was most commonly reported in stage 4 (11.4%). Pain related solely to triggering factors was the most uncommon presentation of pain (3.2%). (4) Characteristics of pain and quality of life tend to differ depending on the reported stage of the endometriosis. Further research may allow a better stage estimation and identification of patients with alarming symptomatic presentation indicative of a progressive stage, even those that are not yet laparoscopically diagnosed.

Reducing health inequalities through general practice in the UK: a realist review (EQUALISE)

Background

In the UK, chronic conditions such as cancer, heart disease, stroke, and chronic obstructive pulmonary disease are driving health inequalities in life expectancy and were responsible for two-thirds of premature mortality in 2017. Voices that stress the importance of primary care in reducing health inequalities have been strengthening during the last decade. However, defining the most effective strategies to reduce health inequalities through general practice remains a challenge.

Aims

This study examines the evidence on interventions in primary care that are likely to decrease inequalities in NCDs and especially cancer, diabetes, cardiovascular and chronic obstructive pulmonary disease and will provide healthcare organisations with guiding principles on what should be commissioned.

Methods

The study is a realist review following Pawson's model. Based on a programme theory, we screened systematic reviews of interventions delivered in primary care and through their references, we identified primary studies reporting on inequalities across PROGRESS-Plus criteria. The data were analysed in light of the initial program theory and organised in a model informed by Collins’ Domains of Power framework.

Results

Out of 251 included reviews we retrieved 6,555 primary studies which resulted in 333 studies for data extraction. We found that there are five guiding principles operating simultaneously across four different domains which can reduce health inequalities in General Practice. The principles include flexibility, continuity, inclusivity, intersectionality, and community and operate simultaneously across the domains of structures and policies; narratives and ideas; rules and practices; and relationships and experience.

Conclusions

Flexibility, continuity, inclusivity, intersectionality, and community are the five principles which should guide the design and delivery of General Practice for the reduction of health inequalities.

Key messages

• Flexibility, continuity, inclusivity, intersectionality, and community are the five principles which should guide the design and delivery of General Practice for the reduction of health inequalities.

• Action to reduce health inequalities should be taken simultaneously across the domains of structures and policies; narratives and ideas; rules and practices; and relationships and experience.

Community-oriented actions by food retailers to support community well-being: a systematic scoping review

OBJECTIVES

Growing inequalities, austerity public funding, and the COVID-19 pandemic have contributed to heightened interest in mobilising the assets and resources within communities to support health and well-being. We aimed to identify the type of actions or initiatives by food retail stores intended to support local communities and contribute to well-being.

STUDY DESIGN

A Scoping Review.

METHOD

A scoping review was conducted in Scopus, Web of Science, and of grey literature to identify the extent of study of food retail stores in supporting community well-being, types and outcomes recorded from community-oriented actions. Data extraction included: population targeted, the content of initiative/action, outcomes recorded and key insights. Studies were grouped into broad categories relating to their actions and objectives.

RESULTS

Actions were associated with either strengthening communities or public health prevention or promotion. Few studies reported clearly on impact, and most accounts of impact on well-being and broader community outcomes were narrative accounts rather than objectively measured. Although rigorous capture of outcomes was absent, there were consistent themes around partnership and community insights that are relevant to the development and implementation of future actions in communities.

CONCLUSIONS

This is an under-researched area that may nevertheless hold potential to support the broader public health effort in communities. To provide clear recommendations for specific investments, there is merit in identifying a subset of health and well-being outcomes most likely to be associated with food retailer community actions in order to assess and capture impact in future. We propose that the theoretical underpinning associated with asset-based approaches, which take account of context and community conditions, would be a useful framework for future study.

The consequences of hyperphagia in people with Prader-Willi Syndrome: A systematic review of studies of morbidity and mortality

Prader-Willi Syndrome (PWS) is a multi-system genetically determined neurodevelopmental disorder and the commonest cause of syndromal obesity. The development of hyperphagia in early childhood is part of the phenotype arising as a result of an impaired neural response to food intake and the inability to regulate food intake in line with energy needs. Severe obesity develops if access to food is not controlled. In this review we evaluate the evidence for increased morbidity and mortality in PWS in order to establish the extent to which it is directly related to the obesity; a consequence of the eating behaviour itself independent of obesity; or associated with other characteristics of the syndrome. Medline, Cochrane, PsychINFO, CINAHL, Web of Science and Scopus databases were used to systematically identify published material on PWS and hyperphagia and syndrome-related morbidity and mortality. One hundred and ten key papers were selected. Data on 500 people with PWS indicated that the average age of death was 21 years and obesity was, as expected, a significant factor. However, the behaviour of hyperphagia itself, independent of obesity, was also important, associated with choking, gastric rupture, and/or respiratory illness. Other syndrome-related factors increased the risk for, and seriousness of, co-morbid illness or accidents. We conclude that improving life-expectancy largely depends on managing the immediate non-obesity and obesity-related consequences of the hyperphagia, through improved support. The development of new treatments that significantly reduce the drive to eat are likely to decrease morbidity and mortality improving quality of life and life expectancy.

Training in the use of intrapartum electronic fetal monitoring with cardiotocography: systematic review and meta‐analysis

Background

Sub‐optimal classification, interpretation and response to intrapartum electronic fetal monitoring using cardiotocography are known problems. Training is often recommended as a solution, but there is lack of clarity about the effects of training and which type of training works best.

Objectives

Systematic review of the effects of training healthcare professionals in intrapartum cardiotocography (PROSPERO protocol: CRD42017064525).

Search strategy

CENTRAL, Cochrane Library, MEDLINE, EMBASE, PsycINFO, British Nursing Database, CINAHL, ERIC, Scopus, Web of Science, ProQuest, grey literature and ongoing clinical trials were searched.

Selection criteria

Primary studies that reported impact of training healthcare professionals in intrapartum cardiotocography. Title/abstract, full‐text screening and quality assessment were conducted in duplicate.

Data collection and analysis

Data were synthesised both narratively and using meta‐analysis. Risk of bias and overall quality were assessed with the Mixed Methods Appraisal Tool and GRADE.

Main results

Sixty‐four studies were included. Overall, training and reporting were heterogeneous, the outcomes evaluated varied widely and study quality was low. Five randomised controlled trials reported that training improved knowledge of maternity professionals compared with no training, but evidence was of low quality. Evidence for the impact of cardiotocography training on neonatal and maternal outcomes was limited, showed inconsistent effects, and was of low overall quality. Evidence for the optimal content and method of delivery of training was very limited.

Conclusions

Given the scale of harm and litigation claims associated with electronic fetal monitoring, the evidence‐base for training requires improvement. It should address intervention design, evaluation of clinical outcomes and system‐wide contexts of sub‐optimal practice.

Tweetable abstract

Training in fetal monitoring: systematic review finds little evidence of impact on neonatal outcomes.

Training in fetal monitoring: systematic review finds little evidence of impact on neonatal outcomes.

Communicating diagnostic uncertainty in the acute and emergency medical setting: A systematic review and ethical analysis of the empirical literature

BACKGROUND

diagnostic uncertainty is ubiquitous. Its communication to patients requires further investigation.

AIMS

To determine: 1) What is known about how and why diagnostic uncertainty is communicated in acute care; 2) evidence of the effects of (not) communicating diagnostic uncertainty in the acute setting; 3) associated ethical issues.

METHODS

systematic review of Medline, Web of Science and SCOPUS for (acute or emergency care) AND (diagnostic uncertainty) AND (ethics OR behaviours). Critical interpretive synthesis and ethical analysis were conducted.

RESULTS AND CONCLUSION

Nine studies (primarily surveys and interviews) were identified. Doctors are not trained in communicating diagnostic uncertainty and perceive it to have negative effects on patients; however not communicating diagnostic uncertainty can disempower patients, resulting in delayed/missed diagnoses or inappropriate use of resource.

Community exchange and time currencies: a systematic and in-depth thematic review of impact on public health outcomes

OBJECTIVES

Austerity in government funding, and public service reform, has heightened expectations on UK communities to develop activities and resources supportive of population health and become part of a transformed place-based system of community health and social care. As non-monetary place-based approaches, Community Exchange/Time Currencies could improve social contact and cohesion, and help mobilise families, neighbourhoods, communities and their assets in beneficial ways for health. Despite this interest, the evidence base for health outcomes resulting from such initiatives is underdeveloped.

STUDY DESIGN

A systematic review.

METHODS

A literature review was conducted to identify evidence gaps and advance understanding of the potential of Community Exchange System. Studies were quality assessed, and evidence was synthesised on 'typology', population targeted and health-related and wider community outcomes.

RESULTS

The overall study quality was low, with few using objective measures of impact on health or well-being, and none reporting costs. Many drew on qualitative accounts of impact on health, well-being and broader community outcomes. Although many studies lacked methodological rigour, there was consistent evidence of positive impacts on key indicators of health and social capital, and the data have potential to inform theory.

CONCLUSIONS

Methodologies for capturing impacts are often insufficiently robust to inform policy requirements and economic assessment, and there remains a need for objective, systematic evaluation of Community Exchange and Time Currency systems. There is also a strong argument for deeper investigation of 'programme theories' underpinning these activities, to better understand what needs to be in place to trigger their potential for generating positive health and well-being outcomes.

Withdrawal of anticancer therapy in advanced disease: a systematic literature review

Background

Current guidelines set out when to start anticancer treatments, but not when to stop as the end of life approaches. Conventional cytotoxic agents are administered intravenously and have major life-threatening toxicities. Newer drugs include molecular targeted agents (MTAs), in particular, small molecule kinase-inhibitors (KIs), which are administered orally. These have fewer life-threatening toxicities, and are increasingly used to palliate advanced cancer, generally offering additional months of survival benefit. MTAs are substantially more expensive, between £2-8 K per month, and perceived as easier to start than stop.

Methods

A systematic review of decision-making concerning the withdrawal of anticancer drugs towards the end of life within clinical practice, with a particular focus on MTAs. Nine electronic databases searched. PRISMA guidelines followed.

Results

Forty-two studies included. How are decisions made? Decision-making was shared and ongoing, including stopping, starting and trying different treatments. Oncologists often experienced ‘professional role dissonance’ between their self-perception as ‘treaters’, and talking about end of life care. Why are decisions made? Clinical factors: disease progression, worsening functional status, treatment side-effects. Non-clinical factors: physicians’ personal experience, values, emotions. Some patients continued treatment to maintain ‘hope’, often reflecting limited understanding of palliative goals. When are decisions made? Limited evidence reveals patients’ decisions based upon quality of life benefits. Clinicians found timing withdrawal particularly challenging. Who makes the decisions? Decisions were based within physician-patient interaction.

Conclusions

Oncologists report that decisions around stopping chemotherapy treatment are challenging, with limited evidence-based guidance outside of clinical trial protocols. The increasing availability of oral MTAs is transforming the management of incurable cancer; blurring boundaries between active treatment and palliative care. No studies specifically addressing decision-making around stopping MTAs in clinical practice were identified. There is a need to develop an evidence base to support physicians and patients with decision-making around the withdrawal of these high cost treatments.

Electronic supplementary material

The online version of this article (doi:10.1186/s12885-015-1862-0) contains supplementary material, which is available to authorized users.

High-performance liquid chromatography method for rapid assessment of viral particle number in crude adenoviral lysates of mixed serotype

Accurate adenovirus (Ad) quantification requires labor- and time-intensive viral stock purification. While crude viral lysates can be titered by plaque assay, this cell-based assay is neither rapid nor accurate. Consequently, a method for quantification of crude, unpurified viral culture lysates is needed. Given growing interest in alternative Ad serotypes (different from well-studied and characterized serotype Ad5) for basic research and for therapeutic applications, such a method should also apply to alternative serotypes. Using a Q Sepharose XL (QSXL) column-based method, we describe a robust quantification method resulting in efficient retention of viral particles of all serotypes, while non-viral components of crude infected cultures remain largely in the flow-through. The high-performance liquid chromatography-QSXL method allows rapid, accurate adenoviral quantification in crude lysates as well as identification of the various serotypes present in mixed-serotype crude lysates. We also report on conditions that efficiently strip and regenerate the column, extending its functional life.

Biochemical fingerprinting of Vibrio parahaemolyticus by the PhenePlate system: comparison between pandemic and non-pandemic serotypes

During recent years a pandemic clone of Vibrio parahaemolyticus has emerged. Isolates of this clone are distributed among several serotypes, but are genotypically related. In the present study, a phenotyping method (biochemical fingerprinting) was used to characterize pandemic and non-pandemic isolates belonging to V. parahaemolyticus. It was found that the pandemic isolates showed a high level of phenotypic homogeneity and a majority of the pandemic isolates belonged to the same biochemical phenotype, whereas non-pandemic V. parahemolyticus isolates were more heterogeneous. In conclusion, biochemical fingerprinting of V. parahaemolyticus can be used as a first screening method to differentiate between pandemic and non-pandemic isolates of V. parahaemolyticus.

A randomised placebo controlled trial of pegylated interferon alpha in active ulcerative colitis

BACKGROUND

Pilot studies of interferon alpha (IFN-alpha) suggest a high remission rate in the treatment of active ulcerative colitis. We evaluated the safety of pegylated interferon alpha (PegIFN) and its role in induction of remission in patients with active ulcerative colitis, in a multicentre placebo controlled trial.

METHODS

Sixty patients with a clinical activity score (CAI) of >6 were randomised to receive placebo (n=20), PegIFN 0.5 microg/kg (n=19), or PegIFN 1.0 microg/kg body weight (n=21) once weekly (PegIntron; Schering-Plough, USA) over 12 weeks. Patients receiving 5-aminosalicylates, steroids, and/or azathioprine in stable dosages were included.

RESULTS

Serious adverse events were seen in none of the placebo patients, in 3/19 patients in the PegIFN 0.5 microg/kg group (hospitalisation due to disease flare up n=3), and in 3/21 in the PegIFN 1.0 microg/kg group (hospitalisation due to disease flare up n=1; thrombosis n=1; grand mal seizure n=1). Otherwise, we observed only minor IFN-alpha side effects. Clinical remission rates at week 12 (CAI < or =4) were 7/20 (35%) in the placebo, 9/19 (47%) in the PegIFN 0.5 microg/kg group, and 7/21 (33%) in the PegIFN 1.0 microg/kg group (NS). Early withdrawal from the study was observed in 11/20 placebo patients, in 6/19 in the PegIFN 0.5 microg/kg group, and in 10/21 in the PegIFN 1.0 microg/kg group, mainly due to lack of efficacy. The higher PegIFN dose was associated with a significant decrease in levels of C reactive protein (p=0.003, day 0 v 85).

CONCLUSIONS

PegIFN is safe but not effective, at the dosages used, in patients with ulcerative colitis.

Treatment of Crohn's disease with recombinant human interleukin 10 induces the proinflammatory cytokine interferon gamma

BACKGROUND

Interleukin 10 (IL-10) exerts anti-inflammatory actions by counteracting many biological effects of interferon gamma (IFN-gamma).

AIMS

To investigate this in humans, we studied the effects of human recombinant IL-10 administration on IFN-gamma production by patient leucocytes. Furthermore, we assessed the IFN-gamma inducible molecule neopterin and nitrite/nitrate serum levels, which are indicative of endogenous nitric oxide formation.

METHODS

As part of two placebo controlled double blind studies, we analysed patients with chronic active Crohn's disease (CACD) who received either subcutaneous recombinant human IL-10 (n=44) or placebo (n=10) daily for 28 days, and patients with mild to moderate Crohn's disease (MCD) treated with either subcutaneous IL-10 (n=52) or placebo (n=16) daily for 28 days. Neopterin and nitrite/nitrate concentrations were measured in serum, and ex vivo IFN-gamma formation by lipopolysaccharide or phytohaemagglutinin (PHA) stimulated whole blood cells were investigated before, during, and after IL-10 therapy.

RESULTS

In patients with CACD, the highest dose of 20 microg/kg IL-10 caused a significant increase in serum neopterin on days +15 and +29 of therapy compared with pretreatment levels. No changes were observed for nitrite/nitrate levels under either condition. In MCD, treatment with 20 microg/kg IL-10 resulted in a significant increase in PHA induced IFN-gamma production.

CONCLUSIONS

High doses of IL-10 upregulate the production of IFN-gamma and neopterin. This phenomenon may be responsible for the lack of efficacy of high doses of IL-10 in the treatment of CACD and MCD.

Identification of AKT-regulated genes in inducible MERAkt cells

AKT/protein kinase B plays a critical role in the phosphoinositide 3-kinase (PI3-kinase) pathway regulating cell growth, differentiation, and oncogenic transformation. Akt1-regulated genes were identified by cDNA array hybridization analysis using an inducible AKT1 protein, MERAKT. Treatment of MERAkt cells with estrogen receptor ligands resulted in phosphorylative activation of MERAKT. Genes differentially expressed in MERAkt/NIH3T3 cells treated with tamoxifen, raloxifene, ICI-182780, and ZK955, were identified at 3 and 20 h. AKT activation resulted in the repression of c-myc, early growth response 1 (EGR1), transforming growth factor beta receptor III (TGF-betar III), and thrombospondin-1 (THBS1). Although c-myc induction is often associated with oncogenic transformation, the c-myc repression observed here is consistent with the anti-apoptotic function of AKT. Repression of THBS1 and EGR1 is consistent with the known pro-angiogenic functions of AKT. AKT-regulated genes were found to be largely distinct from platelet-derived growth factor-beta (PDGFbeta)-regulated genes; only T-cell death-associated gene 51 (TDAG51) was induced in both cases. In contrast to their repression by AKT, c-myc, THBS1, and EGR1 were induced by PDGFbeta, indicating negative interference between elements upstream and downstream of AKT1 in the PDGFbeta signal transduction pathway.

Carbon monoxide production from desflurane, enflurane, halothane, isoflurane, and sevoflurane with dry soda lime

BACKGROUND

Previous studies in which volatile anesthetics were exposed to small amounts of dry soda lime, generally controlled at or close to ambient temperatures, have demonstrated a large carbon monoxide (CO) production from desflurane and enflurane, less from isoflurane, and none from halothane and sevoflurane. However, there is a report of increased CO hemoglobin in children who had been induced with sevoflurane that had passed through dry soda lime. Because this clinical report appears to be inconsistent with existing laboratory work, the authors investigated CO production from volatile anesthetics more realistically simulating conditions in clinical absorbers.

METHODS

Each agent, 2.5 or 5% in 2 l/min oxygen, were passed for 2 h through a Dräger absorber canister (bottom to top) filled with dried soda lime (Drägersorb 800). CO concentrations were continuously measured at the absorber outlet. CO production was calculated. Experiments were performed in ambient air (19-20 degrees C). The absorbent temperature was not controlled.

RESULTS

Carbon monoxide production peaked initially and was highest with desflurane (507 +/- 70, 656 +/- 59 ml CO), followed by enflurane (460 +/- 41, 475 +/- 99 ml CO), isoflurane (176 +/- 2.8, 227 +/- 21 ml CO), sevoflurane (34 +/- 1, 104 +/- 4 ml CO), and halothane (22 +/- 3, 20 +/- 1 ml CO) (mean +/- SD at 2.5 and 5%, respectively).

CONCLUSIONS

The absorbent temperature increased with all anesthetics but was highest for sevoflurane. The reported magnitude of CO formation from desflurane, enflurane, and isoflurane was confirmed. In contrast, a smaller but significant CO formation from sevoflurane was found, which may account for the CO hemoglobin concentrations reported in infants. With all agents, CO formation appears to be self-limited.

In vivo effects of recombinant human interleukin-10 on lymphocyte phenotypes and leukocyte activation markers in inflammatory bowel disease

BACKGROUND

Interleukin-10 (IL-10) exhibits potent anti-inflammatory and immunosuppressive activities in vitro. Recent data indicate that treatment with recombinant human IL-10 (rHuIL-10) Crohn's disease is safe and may induce clinical and endoscopic remission. The present study investigates the in vivo immunomodulatory properties of rHuIL-10 in inflammatory bowel disease (IBD).

METHODS

As part of two randomized, double-blinded, placebo-controlled trials, repeated flow cytometric analyses of lymphocyte phenotypes (CD3, CD4, CD8, CD16 + 56, CD19) and activity markers (human leukocyte antigen [HLA]-DR; intercellular adhesion molecule-1 [ICAM-1]; IL-2-receptor alpha [IL-2R alpha]; high affinity receptor for immunoglobulin G [IgG; Fc gamma RI]) on T cells, monocytes, and neutrophils were performed in 17 patients with IBD who received rHuIL-10 (5, 10, or 20 micrograms/kg) or placebo, administered subcutaneously, once daily for 28 days.

RESULTS

Minor changes were noted in CD3+, CD8+, and CD3+/CD16 + 56+ lymphocyte phenotypes, whereas absolute numbers of CD4+ lymphocytes and CD19+ cells increased. T-cell activation markers HLA-DR and IL-2R alpha were downregulated. rHuIL-10 did not influence HLA-DR expression on monocytes. ICAM-1 modulation on monocytes and neutrophils was mild and inconsistent. Fc gamma RI expression was upregulated on both neutrophils and monocytes.

CONCLUSIONS

These data indicate that the immunosuppressive effects of rHuIL-10 treatment are partly different from its in vitro observed actions. The increase of the cytotoxicity-mediating Fc gamma RI points to potential immunostimulating properties of this cytokine.

The effect of desflurane on liver function markers in infants and children. Report of a study and a pertinent case report

BACKGROUND

In an open-labelled clinical trial, the effect of desflurane anaesthesia on liver function markers in paediatric patients was monitored.

METHODS

Fifty infants and children, 37 male, scheduled for elective cleft plate surgery were included in the study. Median age was 0.57 (0.25-5.45) years (range), mean desflurane exposure was 2.29 +/- 0.75 MAC-h. Function markers were determined within 24 h prior to and within 24-48 h after anaesthesia. Complete data sets were available for total bilirubin 29, aspartate aminotransferase (ASAT) 36, alanine aminotransferase (ALAT) 35, and for alkaline phosphatase (AP) 28. Pre- and postanaesthetic function tests were compared by means of Wilcoxon's matched-pairs test.

RESULTS

Only for AP could a statistically significant reduction of the postanaesthetic values be observed, while the other parameters showed no significant changes. Postanaesthetic ASAT and ALAT were clearly reduced in three children who had unspecific highly elevated preanaesthetic values. After the study, this observation could be repeated in at least one child, who received a further anaesthesia with desflurane within 3 months.

CONCLUSION

The data suggest that desflurane does not affect excretory or structural liver integrity in infants and children.

Prevalence of enterotoxin genes in Aeromonas spp. isolated from children with diarrhea, healthy controls, and the environment

Aeromonads are causative agents of a number of human infections. Even though aeromonads have been isolated from patients suffering from diarrhea, their etiological role in gastroenteritis is unclear. In spite of a number of virulence factors produced by Aeromonas species, their association with diarrhea has not been clearly linked. Recently, we have characterized a heat-labile cytotonic enterotoxin (Alt), a heat-stable cytotonic enterotoxin (Ast), and a cytotoxic enterotoxin (Act) from a diarrheal isolate of Aeromonas hydrophila. Alt and Ast are novel enterotoxins which are not related to cholera toxin; Act is aerolysin related and has hemolytic, cytotoxic, and enterotoxic activities. We studied the distribution of the alt, ast, and act enterotoxin genes in 115 of 125 aeromonads isolated from 1, 735 children with diarrhea, in all 27 aeromonads isolated from 830 control children (P = 7 x 10(-4) for comparison of rates of isolation of aeromonads from cases versus those from controls), and in 120 randomly selected aeromonads from different components of surface water in Bangladesh. Aeromonas isolates which were positive only for the presence of the alt gene had similar distributions in the three sources; the number of isolates positive only for the presence of the ast gene was significantly higher for the environmental samples than for samples from diarrheal children; and isolates positive only for the presence of the act gene were not found in any of the three sources. Importantly, the number of isolates positive for both the alt and ast genes was significantly higher for diarrheal children than for control children and the environment. Thus, this is the first study to indicate that the products of both the alt and ast genes may synergistically act to induce severe diarrhea. In 26 patients, Aeromonas spp. were isolated as the sole enteropathogen. Analysis of clinical data from 11 of these patients suggested that isolates positive for both the alt and ast genes were associated with watery diarrhea but that isolates positive only for the alt gene were associated with loose stools. Most of the isolates from the three sources could be classified into seven phenospecies and eight hybridization groups. For the first time, Aeromonas eucrenophila was isolated from two children, one with diarrhea and another without diarrhea.

Developmental regulation of the cell division protein FtsZ in Anabaena sp. strain PCC 7120, a cyanobacterium capable of terminal differentiation

Heterocysts are terminally differentiated cells devoted to nitrogen fixation in the filamentous cyanobacterium Anabaena sp. strain PCC 7120. We show here that the cell division protein FtsZ is present in vegetative cells but undetectable in heterocysts. These results provide a first rational explanation for the inability of mature heterocysts to undergo cell division.

Pharmacokinetics of inhaled anaesthetics in a clinical setting: description of a novel method based on routine monitoring data

Pharmacokinetic parameters of inhaled anaesthetics have previously been assessed experimentally in healthy volunteers. In contrast, we developed a method to estimate pharmacokinetic parameters under clinical conditions. We obtained data from the continuous routine monitoring of fractional concentration and ventilation during anaesthesia with desflurane, isoflurane and sevoflurane. By simulation studies, we assessed the effects of several sources of variation, including the noise of measurement, the second gas effect and rounding errors or a limited number of displayed digits. Stable fits to a two-compartment model were obtained for both real and simulated data sets in all cases. The most stable parameter was the intercompartmental clearance, and the most sensitive parameter was the volume of distribution. The bias in pharmacokinetic parameters caused by adding errors to measured concentrations was similar for the different compounds. We conclude that the model allows the estimation of an alternative set of pharmacokinetic parameters that can reliably describe the behaviour of volatile anaesthetics under clinical conditions, and allow comparison between agents.

Pharmacokinetics of inhaled anaesthetics in a clinical setting: comparison of desflurane, isoflurane and sevoflurane

The pharmacokinetic characteristics of desflurane, isoflurane and sevoflurane (16 patients for each anaesthetic) were estimated from measurements of inspired and end-expired agent concentrations and ventilation, obtained during routine anaesthesia in patients undergoing maxillofacial surgery (mean age 38 yr, duration of anaesthesia approximately 2 h). A two-compartment model described the data adequately. Although isoflurane and sevoflurane have almost the same tissue/blood partition coefficients, significant differences between substances were observed for the peripheral volume of distribution (medians and ranges: desflurane, 612 (343-1850) mlvapour kgbw-1; isoflurane, 4112 (1472-9396) mlvapour kgbw-1; sevoflurane, 1634 (762-8843) mlvapour kgbw-1) and the transport clearance from the central to the peripheral compartment (desflurane, 7.0 (4.4-11.1) mlvapour kgbw-1 min-1; isoflurane, 30.7 (15.9-38.7) mlvapour kgbw-1 min-1; sevoflurane, 13.0 (9.8-22.4) mlvapour kgbw-1 min-1). Thus, during clinical anaesthesia the important characteristics of the compounds could be obtained and compared between substances from simple data.

Incidence of nausea and vomiting in children after strabismus surgery following desflurane anaesthesia

In a prospective, randomized parallel study, 60 ASA I-III children aged 1-17 years, scheduled for elective strabismus surgery, were anaesthetized with desflurane without prophylactic antiemetic medication. The objective of the study was to determine the incidence of postoperative nausea and vomiting after general anaesthesia with desflurane. To decide whether nitrous oxide further influences these symptoms, the patients were randomly assigned to two groups of 30 patients each. One group received desflurane in oxygen/air and a second group received desflurane in oxygen/nitrous oxide. In all children, after intravenous induction and tracheal intubation, anaesthesia was administered as minimal flow anaesthesia with oxygen and nitrous oxide or air according to the random plan. The patients were observed for 48 postoperative hours until their discharge from the ward. The overall incidence of nausea was found to be 37%, and vomiting was seen in 32% of all patients. No statistical correlation was found between the incidence of postoperative emesis and the administration of nitrous oxide or the duration of general anaesthesia. Instead, the incidence of vomiting was 2.5-fold higher when surgery was performed on both eyes compared with one eye. The relatively low incidence of postoperative nausea and vomiting, as well as the quick recovery from anaesthesia, permitting an early discharge from the postoperative care unit to the ward, show desflurane to be a suitable volatile anaesthetic in strabismus surgery in children.

Characterization of the biotin biosynthesis pathway in Saccharomyces cerevisiae and evidence for a cluster containing BIO5, a novel gene involved in vitamer uptake

An engineered mutant of Saccharomyces cerevisiae affected in biotin biosynthesis has been isolated. This mutant allowed the characterization of a bio cluster (BIO3-4-5). We demonstrate that BIO3 (YNR058w) and BIO4 (YNR057c) encode, respectively, a 7, 8-diaminopelargonic acid aminotransferase and a dethiobiotin synthase, involved in the biotin biosynthesis pathway. A novel gene, BIO5 (YNR056c), is present immediately downstream from BIO4. This gene encodes Bio5p, a protein with 11 putative transmembrane regions. Uptake experiments performed with labeled 7-keto 8-aminopelargonic acid indicate that Bio5p is responsible for transport into the cell of 7-keto 8-aminopelargonic acid.

[Anti-bradycardia ventricle stimulation during the vulnerable phase of the heart cycle in ICD system with DDD cardiac pacemaker function]

We report a case of a 56-year-old white female with an ICD system (Ventak AV, CPI) implanted because of repeated episodes of ventricular fibrillation and preexisting intermittent total AV-block. Several times asynchronic stimulation could be observed in the case of ventricular extrasystole stimulating the ventricle during different times of depolarization. The reason for undersensing of the premature ventricular complexes was a blanking period of 66 ms after atrial stimulation. Therefore, the ICD was not able to sense the ventricular extrasytole and the stimulation of the ventricle occurred during the vulnerable period of the heart cycle. Induction of severe ventricular arrhythmia was not documented. Because of missing programmability of the ventricular blanking period, no possibility of a safety stimulation, and already maximal sensitivity of the ICD, the incidence of these events could only be reduced by increasing the lower rate limit of the pacemaker and suppression of the premature ventricular complexes by medication.

[Heat production from reaction of inhalation anesthetics with dry soda lime]

There are some case reports about excessive heat production in the absorbent canister when sevoflurane or enflurane are washed into a circle containing dried soda lime. This observation was often made in the DRAGER ISO 8 circle system with the gas inlet upstream of the soda lime canister with the gas-flow from bottom to top.

METHODS

The temperature in the center of an absorbent canister was measured 3.0 cm and 7.5 cm above the bottom. Soda lime (DRAGERSORB 800) was dried in an O2 stream for 2-3 days until there was no further loss in weight. 5 Vol% of desflurane, enflurane, isoflurane and sevoflurane in 2 1/min O2 or 4 Vol% of halothane in 2.5 I/min O2 were continuously fed into the canister. The concentration of the respective inhalational agents were measured after the soda lime canister using a DATEX Capnomac. Experiments were performed at ambient temperatures of 20-22 degrees C.

RESULTS

A considerable temperature increase was achieved with all anaesthetics. The highest temperatures were measured at the upper sensor with 56-58 degrees C for desflurane, 76-80 degrees C for enflurane and isoflurane, 84-88 degrees C for halothane and 126-130 degrees C for sevoflurane. IR-detection for some agents was considerably delayed or the time course indicated that other compounds might have formed which absorb at the wavelength monitored.

DISCUSSION

The high temperatures indicate the degradation rather than absorption of the volatile anaesthetics. CO is known to be degradation product of all currently used volatile anaesthetics except sevoflurane. Sevoflurane, however, produced the highest temperatures passing through dried soda lime. There are no reports about new specific breakdown products for sevoflurane on dried soda lime.

[The temperature-humidity profile of the PhysioFlex. Studies on a model]

Closed-system anaesthesia provides the best prerequisites for optimal warming and humidification of anaesthetic gases. The PhysioFlex anaesthesia machine fascilitates quantitative closed-system anaesthesia. Furthermore, its design may improve the climatization of the anaesthetic gases by revolving the system volume at 70 l/min, using a small soda-lime canister to allow optimal usage of the heat and moisture generated by CO2 absorption and by integrating all system components in thermally isolating housing. To determine the capacity of the PhysioFlex to climatize anaesthetic gases, we evaluated the heat and humidity profile at four characteristic places in the anaesthetic circuit under standardised conditions in a model.

MATERIALS AND METHODS

In an air-conditioned room at 19-20 degrees C ambient temperature, the PhysioFlex was operated with a fresh gas flow of less than 500 ml/min, similar to quantitative closed-system anaesthesia in adults. With a respiratory rate of 10/min and a tidal volume of 600 ml, a humidifier was ventilated, that delivered humidity-saturated gas at 33-34 degrees C; 200 ml/min CO2 were added to the system at the humidifier to mimic the heat, moisture, and CO2 input of a patient into the anaesthetic circuit. A total of six series were performed, each starting with a cold and dry anaesthetic circuit. For 2 h the time-courses of temperature and humidity of the anaesthetic gases were measured at four distinct places: (1) in the soda-lime canister (M1); (2) at the outlet of the anaesthesia machine (M2); (3) at the inlet of the anaesthesia machine (M3); and (4) in the inspiratory limb close to the Y-piece (M4). Capacitive humidity sensors (VAISALA Type HMM 30 D without a protective cap) and very small thermocouples were used to measure relative humidity (rH) and temperature. The data were recorded at 5 min intervals. Due to the continuous gas stream in the system, the response time of the sensors, which is in the range of a few seconds, did not affect the accuracy of the measurement. With the temperature-dependent humidity content of 100% rH obtained from equation 1, absolute humidity was calculated.

RESULTS

The time courses of temperature and humidity at the different measuring points are depicted in Figs. 2 and 3, respectively. The steepest increase in temperature and humidity was observed at M1. Within 10 min 100% rH was achieved at all measuring points. Initially, there was a considerable temperature gradient between M1 and M2; this became gradually smaller, indicating system components with high heat capacities. There was only a small gradient between M2 and M4, indicating that there was only a small heat loss compared to the heat input. The recommended minimal climatization of the anaesthetic gases of 20 mg H2O/l [20] was obtained within 10 min at M4. During the whole measuring period heat and humidity increased in the system, reaching a maximum at M4 after 120 min with average values of more than 28 degrees C and 27 mg H2O/l, respectively.

CONCLUSION

With the PhysioFlex anaesthesia machine employing closed-system conditions, minimal climatization of anaesthetic gases was reached within 10 min. After a period of 120 min, the anaesthetic gases were nearly climatized to the extent recommended for long-term respiratory therapy. To date, no comparable temperature and humidity level has been reported with conventional anaesthesia machines. The time course of the gradient between M1 and M2 may give an opportunity for further optimising the system in reducing heat loss after the soda-lime canister, the active heat and moisture source in the circuit. At about 32 degrees C, the temperature in the soda-lime canister is 10-15 degrees C less than in conventional anaesthesia machines. Thus, the use of thermally instable volatile anaesthetics in the PhysioFlex under closed-system conditions may be less critical than in conventional anaesthesia machines under minimal-flow conditions.

[Effect of halothane, enflurane and isoflurane on the pharmacodynamics of mivacurium in children]

INTRODUCTION AND OBJECTIVE

Mivacurium is a new non-depolarising muscle relaxant with a relatively rapid onset and short duration of action. In children, intravenous injection of 0.2 mg/kg produces satisfactory relaxation. Because inhalational anaesthetics have been found to enhance the potency of muscle relaxants we determined if onset or recovery times following mivacurium are influenced by inhalation of halothane (HAL), enflurane (ENF) or isoflurane (ISO).

METHODS

After intramuscular induction, 36 surgical children (2-6 years, ASA I) were randomly assigned to inhale either HAL (n = 12); ENF (n = 12) or ISO (n = 12). The train-of four (TOF) response was determined electromyographically (Relaxograph, Datex) at 20-second time intervals. Following ten minutes of inhalation of either HAL, ENF or ISO (0,8; 1,2; 1,0 vol% respectively) in N2 O/O2 (2:1), 0.2 mg/kg of mivacurium was injected intravenously. Patients were intubated at maximal T1-suppression and the intubating conditions were judged according to a graded score. Upon recovery of T1 = 25%, six patients in each group were antagonised with 30 micrograms/kg of neostigmine and 15 micrograms/kg of atropine; the recovery indices were compared with those from non-antagonised patients. Differences between groups were tested with multifactorial analysis of variance (p < 0.05).

RESULTS

Intubating conditions were graded as "excellent" or "good" in all patients but one who showed moderate breath holding following the tube passage. Onset times of mivacurium were not different between patients receiving HAL: 2.4 min +/- 0.52 (+/ SD); ENF: 2.4 min +/- 0.55 or ISO: 2.6 min +/- 0.68. Time to T1 = 25% was 7.6 min +/- 2.91 (HAL); 7.9 min +/- 1.55 (ENF) and 8.6 min +/- 2.30 (ISO). Recovery indices were not significantly different between groups. Total duration of action in non-antagonised patients was 13.0 min +/- 3.32 (HAL); 14.3 min +/- 4.01 (ENF) and 19.6 min +/- 5.17 (ISO), whereas antagonised duration of action was 13.4 min +/- 5.11 (HAL); 13.3 min +/- 1.97 (ENF) and 15.6 min +/- 4.25 (ISO). The shorter total duration of action in patients receiving neostigmine (average 0.5-2 minutes) was statistically insignificant.

DISCUSSION AND CONCLUSION

Following injection of 0.2 mg/kg of mivacurium, no clinically relevant differences in onset or recovery times were found between children receiving halothane, enflurane or isoflurane. No differences in heart rate or blood pressure were found between groups. Compared to previous investigations with mivacurium, we noted a 30-60% longer mean onset time and a 30% shorter mean spontaneous recovery time. This may be explained by the lower mean age of our patients, which correlates with a relatively higher volume of distribution, resulting in lower plasma concentrations if the dose is calculated per kilogramme body weight. The reduction of the mean recovery time by 2 minutes following neostigmine injection seems to be clinically irrelevant. Similar to adult, a twofold ED95 produces satisfactory surgical muscle relaxation in children receiving mivacurium. Thus, its onset time is comparable to that of vecuronium or atracurium. The shorter duration of action offering a tighter control over relaxation may be of clinical advantage in this age group.

Oxidation of a specific methionine in thrombomodulin by activated neutrophil products blocks cofactor activity. A potential rapid mechanism for modulation of coagulation

Endothelial thrombomodulin (TM) plays a critical role in hemostasis as a cofactor for thrombin-dependent formation of activated protein C, a potent anticoagulant. Chloramine T, H2O2, or hypochlorous acid generated from H2O2 by myeloperoxidase rapidly destroy 75-90% of TM cofactor activity. Activated PMN, the primary in vivo source of biological oxidants, also rapidly inactivate TM. Oxidation of TM by PMN is inhibited by diphenylene iodonium, an inhibitor of NADPH oxidase. Both Met291 and Met388 in the six epidermal growth factor-like repeat domain are oxidized; however, only substitutions of Met388 lead to TM analogues that resist oxidative inactivation. We suggest that in inflamed tissues activated PMN may inactivate TM and demonstrate further evidence of the interaction between the inflammatory process and induction of thrombotic potential.

Structure-function studies of the epidermal growth factor domains of human thrombomodulin

Structure-function relationships in the 6 epidermal growth factor-like domains of human thrombomodulin (TME, residues 227-462) were studied by deletion mutagenesis. Purified and characterised proteins were used for kinetic studies. Deletion of EGF1, EGF2 and residues 310-332 in EGF3 had no effect on thrombin binding (Kd) or on kcat/KM for protein C activation by the thrombin-thrombomodulin complex. Deletion of the rest of EGF3 and the interdomain loop between EGF3 and EGF4 had no effect on Kd but decreased kcat/KM to 10% of TME. Deletion of residues 447-462 of EGF6 had no effect on kcat/KM but increased Kd for thrombin approximately 6-fold. Thus, the region 333-350 in EGF3-4 is critical for protein C activation by the thrombin-thrombomodulin complex and the region 447-462 in EGF6 is critical for thrombin binding.

Gastric potential difference measurement as a quantification of gastrointestinal tolerability comparing a buffered acetylsalicylic acid formulation versus plain acetylsalicylic acid

Two different acetylsalicylic acid (ASA, CAS 50-78-2) formulations (Aspirin) were compared regarding their gastric mucosal tolerability. After administration of plain ASA, buffered ASA and ASA placebo the decrease of gastric potential difference (GPD) was measured. Evaluation of the GPD parameters showed a better tolerability of buffered ASA than of plain ASA. It was therefore concluded that buffered ASA effects less gastric mucosal irritation than plain ASA.

Renal elimination of magnesium as a parameter of bioavailability of oral magnesium therapy

Magnesium is an important cation in human physiology, especially in the regulation of membrane proteins, as a cofactor for various enzyme systems and in neuromuscular transmission. Magnesium deficiency leads to severe impairment in muscle function, particularly in cardiovascular diseases. Classical bioavailability studies with magnesium cannot be carried out for several reasons. As the magnesium concentration in plasma is extraordinarily well regulated, renal elimination proves to be the best method to determine the absorption of orally administered magnesium. Magnesium pools must first be filled, and the saturation phase of renal elimination then equals the degree of absorption. This parameter of bioavailability shows the percentage of eliminated magnesium in comparison to the administered dose. Eighteen healthy male volunteers were included in this study to compare 5 mg magnesium-DL-hydrogen aspartate with magnesium-L-hydrogen aspartate. After a saturation phase, the test substances were administered in random order. Blood samples for determination of magnesium concentrations were taken, but no typical pharmacokinetic concentration curves were obtained. The areas under the concentration-time curves were equal for both formulations (x = 40.22 [mval*h/l]). The bioavailability of both substances was determined from the renal elimination. No significant difference was found between both treatments. Bioavailability of 5 mg magnesium-DL-hydrogen aspartate was 44.5% and for magnesium-L-hydrogen aspartate 41.7%. It is evident that this method of magnesium determination is practical, comfortable for volunteers and gives reliable results in comparing the absorption of magnesium formulations.

Iontophoresis--is there a future for clinical application?

Transdermal application of drugs is a field of great importance in medical therapy. The application is painless and may be controlled at any time. Iontophoresis is one method for transdermal application of substances, especially for larger or charged molecules which cannot be administered by a simple transdermal route. The problems arise from the complex equipment and the electrical properties of the skin. A better understanding of skin structure and electric transmission through human skin has led to renewed interest in iontophoresis as an administration mode. Iontophoresis is the method of choice in administration of certain local anesthetics and has had its greatest success in therapy of hyperhidrosis. New applications are to be expected, particularly in administration of peptide and protein drugs.

Vaccination against polyoma virus (PyV) tumors using vaccinia-PyV recombinants: a major tumor-specific transplantation antigen (TSTA) epitope resides within the C-terminal segment of middle-T protein

We previously reported that inoculation of rats with live vaccinia virus (VV) recombinants VVpyMT, VVpyLT expressing either the middle-T (MT) or large-T (LT) proteins of polyomavirus (PyV) can elicit immunity to challenge with syngeneic PyV-tumor cells. We now report the results of cross-vaccination studies. VVpyMT was ineffective against cells expressing LT protein but prevented development of MT-expressing cells. Conversely, the VVpyLT was ineffective against MT-expressing cells. In the two experiments performed, tumor growth enhancement rather than retardation was observed in VVpyLT-vaccinated animals receiving PyV-LT (FRLTI) challenge tumor cells. To determine the location of the major TSTA within MT, a further VV recombinant (VVpyMT/Cfr) was constructed that expresses only the unique C-terminal segment of MT. VVpyMT-Cfr and VVpyMT were equally effective in eliciting tumor immunity, indicating the presence of a major TSTA epitope within the unique C-terminal region of MT.

Characterization of a surface antigen of Eimeria tenella sporozoites and synthesis from a cloned cDNA in Escherichia coli

An antigenic surface protein of Eimeria tenella sporozoites has been identified that is the target of two neutralizing monoclonal antibodies Ptn 7.2A4/4 and Ptn 9.9D12. The antigen as isolated from the parasite is composed of a 17 kDa polypeptide and a 8 kDa polypeptide linked by a disulfide bridge. De novo synthesis of the antigen does not begin until approximately 16-20 h after the initiation of oocyst sporulation. A cDNA library was constructed using mRNA from sporulated oocysts and a clone encoding the antigen was isolated. The Ta4 gene encodes a single polypeptide of 25 kDa which contains the 17 and 8 kDa polypeptides. The protein has been synthesized in Escherichia coli either directly or as part of a beta-galactosidase fusion protein. The products synthesized in E. coli are single polypeptides and are not cleaved to two polypeptides as is seen in the parasite. The products accumulate in bacteria in an insoluble form which can be solubilized and renatured to an immunoreactive form.

Positive-selection vectors utilizing lethality of the EcoRI endonuclease

The construction and use of a series of positive-selection vectors are described. These plasmids encode EcoRI endonuclease, the synthesis of which is under the control of the lacUV5 promoter. The pKG2 plasmid encodes a wild-type EcoRI endonuclease. In the absence of EcoRI methylase, the endonuclease is lethal. Cloning into any of the unique restriction sites within the endonuclease-coding gene allows survival of the transformed EcoRI-methylase-less host. The pKGW and pKGS plasmids encode an altered EcoRI endonuclease which, when repressed in a lacIQ host, allows survival in the absence of the methylase. Induction with IPTG, however, results in cell death as a result of high-level EcoRI synthesis. Cloning into any of the unique restriction sites within the EcoRI gene of pKGW or pKGS allows survival of derepressed transformed cells. These vectors strongly select for cloning events which inactivate the endonuclease gene.