Current practice and provision of oncoplastic breast-conserving surgery in the UK: results of the ANTHEM national practice questionnaire

PURPOSE

Oncoplastic breast-conserving surgery (OPBCS) may be a better option than mastectomy ± immediate breast reconstruction (IBR) for women with breast cancer but studies directly comparing the techniques are lacking. We surveyed UK breast units to determine the current practice of OPBCS to inform the design of a future comparative study.

METHODS

An electronic survey was developed to explore the current practice of OPBCS. This included the local availability of volume displacement and/or replacement techniques; number of cases performed; contraindications and approach to contralateral symmetrisation. Summary data for each survey item were calculated and overall provision of care examined.

RESULTS

58 UK centres completed the survey, including 43 (74%) stand-alone breast and 15 (26%) combined breast/plastics units. Over 40% of units (n = 24) treated more than 500 cancers/year. Most units offered volume displacement techniques (TMs) (97%). Over two-thirds (n = 39. 67%) of units offered local perforator flaps (LPF). Approximately a half of units (10/19) not performing LPF were planning to introduce them in the next 12-24 months. A third (n = 19, 33%) of units routinely performed simultaneous contralateral symmetrisation mostly with two-surgeon operating. There were limited oncological restrictions to OPBCS with no contraindications for multifocal cancers in most centres; 65% of units (36/55) offered OPBCS for multicentric disease. Extensive DCIS was a contraindication in a minority of units.

CONCLUSIONS

OPBCS is widely available in the UK but contraindications and approaches to contralateral symmetrisation were variable. Work is now needed to prospectively evaluate the outcomes of OPBCS vs mastectomy ± IBR to support informed decision-making.

Protocol for a mixed-method study to inform the feasibility of undertaking a large-scale multicentre study comparing the clinical and patient-reported outcomes of oncoplastic breast conservation as an alternative to mastectomy with or without immediate breast reconstruction in women unsuitable for standard breast-conserving surgery (the ANTHEM Feasibility Study)

INTRODUCTION

Approximately 40% of the 55 000 women diagnosed with breast cancer each year in the UK undergo mastectomy because they are considered unsuitable for standard breast-conserving surgery (BCS) due to tumour size or multiple tumour foci. Mastectomy can significantly impact women's quality of life, and only one in four women currently undergo immediate breast reconstruction (IBR).Level 2 oncoplastic breast-conserving surgery (OPBCS) combines removing the cancer with a range of plastic surgical volume replacement (eg, local perforator flaps) and volume displacement techniques (eg, therapeutic mammaplasty) that can extend the role of BCS and may allow some women not suitable for standard BCS to avoid mastectomy. High-quality research to determine whether OPBCS offers a safe and effective alternative to mastectomy±IBR is currently lacking. Preliminary work is needed to ensure a future large-scale study is feasible and well designed and addresses questions important to patients and the National Health Service.

METHODS AND ANALYSIS

Mixed methods will be used to inform feasibility and design of a future large-scale study comparing the clinical effectiveness and cost-effectiveness of OPBCS and mastectomy±IBR. It will have four parts: (1) a National Practice Questionnaire to determine current practice and provision of oncoplastic breast and reconstructive surgery in the UK; (2) a pilot multicentre prospective cohort study to explore the proportion of patients choosing OPBCS versus mastectomy, the proportion in OPBCS is successful and clinical and patient-reported outcomes of different techniques at 3 and 12 months postsurgery; (3) a qualitative interview study to explore patients' attitudes to different procedures, rationale for decision-making and perceptions of outcomes; and (4) design of the future study.All centres offering OPBCS and mastectomy in the UK will be invited to participate. Recruitment is planned to commence winter 2020 and continue for 12 months.

ETHICS AND DISSEMINATION

The study has ethical approval from the Wales Research Ethics Committee 6 National Research Ethics Service (REC Ref 20/WA/0225). Results will be presented at national and international meetings and published in peer-reviewed journals. We will work with patients to develop lay summaries and share these through patient groups and breast cancer charities.

TRIAL REGISTRATION NUMBER

ISRCTN18238549.

Changing practice: moving to a specialist nurse-led service for BRCA gene testing

Some 5–10% of all breast cancers are associated with a pathogenic variant in a breast cancer-associated gene (BRCA1/BRCA2). Historically, with referral to the Nottingham University Hospitals NHS Trust's clinical genetics department for genetic testing, waiting times were on average 12–14 weeks for an initial appointment and 4–6 months to obtain results from the date of testing. A specialist, nurse-led mainstreaming cancer genetics (MCG) service was set up in the trust's Nottingham Breast Institute (NBI) to: reduce waiting times for the initial consultation, counselling, consent and obtaining results for BRCA1/BRCA2 gene testing; and to ensure appropriate patients with breast cancer were offered genetic testing. Two breast clinical nurse specialists were trained so they could counsel, consent and give results for the BRCA1/BRCA2 gene testing directly to patients. Average waiting times for results from the time of testing were reduced to 35.8 days under the nurse-led service, which enabled oncologists and patients to consider individual treatment options at an earlier time. The MCG service reduced waiting times, resulting in an improved, more streamlined service for patients undergoing genetic testing. The MCG service extended the scope of practice of the breast nurse clinical specialists, embedded an expert advanced nursing role in the breast multidisciplinary team and developed nurse mentoring opportunities.

Surgical management of ductal carcinoma in situ of the breast: A large retrospective study from a single institution

BACKGROUND

Management of breast ductal carcinoma in situ (DCIS) has various approaches with distinct institutional specific practice. Here, we review DCIS management in a single institution with emphasize on re-operation rates and outcome.

METHODS

Breast ductal carcinoma in situ cases diagnosed at the Nottingham Breast Institute between 1987 and 2017 were identified (n = 1249). Clinicopathological data were collected. Cases were histologically reviewed, and different factors associated with primary operation selection, re-excision, presence of residual tumor in the re-excision specimens, use of radiotherapy and ipsilateral recurrences were analyzed.

RESULTS

34% of DCIS patients were initially treated by mastectomy and were more frequently symptomatic, of high nuclear tumor grade, size >40 mm, and associated with comedo necrosis and Paget's disease of the nipple. Further surgery was due to involved or narrow surgical margins. Residual tumor tissue was detected in 53% of the re-excision specimens. Re-excision rates of patients treated with breast-conserving surgery (BCS) were reduced from approximately 70% to 23%, and the final mastectomy rates decreased from 60% to 20%. Changes in surgical practice with acceptance of smaller excision margins and more frequent use of local radiotherapy have led to a significant decrease not only in the re-excision rate but also in the final mastectomy rate together with non-significant reduction in 5- and 10-year local recurrence rates.

CONCLUSION

Although BCS is increasingly the preferred primary surgical option for DCIS management, a proportion of low-risk DCIS patients continue to undergo re-excision surgery or completion mastectomy. Despite acceptance of smaller margins, recurrence rate is decreasing.

Prepectoral implant-based breast reconstruction: a joint consensus guide from UK, European and USA breast and plastic reconstructive surgeons

Advances in implantable biologic and synthetic products over the last decade have enabled surgeons to replace traditional submuscular implant-based breast reconstruction techniques with a prepectoral or muscle-sparing technique. Prepectoral breast reconstruction is becoming increasingly popular among surgeons and patients due to the preservation of normal chest wall anatomy, with the restoration of body image with minimal morbidity. In this article, we have described a guide to prepectoral or muscle-sparing breast reconstruction with a particular emphasis on patient selection, technique and postoperative outcomes. Hence, a joint consensus guide from European and USA breast and plastic reconstructive surgeons has been agreed, and a crowd-writing method has been adopted to produce this guide.

Evaluation of mammographic surveillance services in women aged 40-49 years with a moderate family history of breast cancer: a single-arm cohort study

BACKGROUND

Women with a significant family history of breast cancer are often offered more intensive and earlier surveillance than is offered to the general population in the National Breast Screening Programme. Up to now, this strategy has not been fully evaluated.

OBJECTIVE

To evaluate the benefit of mammographic surveillance for women aged 40-49 years at moderate risk of breast cancer due to family history. The study is referred to as FH01.

DESIGN

This was a single-arm cohort study with recruitment taking place between January 2003 and February 2007. Recruits were women aged < 50 years with a family history of breast or ovarian cancer conferring at least a 3% risk of breast cancer between ages 40 and 49 years. The women were offered annual mammography for at least 5 years and observed for the occurrence of breast cancer during the surveillance period. The age group 40-44 years was targeted so that they would still be aged < 50 years after 5 years of surveillance.

SETTING

Seventy-four surveillance centres in England, Wales, Scotland and Northern Ireland.

PARTICIPANTS

A total of 6710 women, 94% of whom were aged < 45 years at recruitment, with a family history of breast cancer estimated to imply at least a 3% risk of the disease between the ages of 40 and 50 years.

INTERVENTIONS

Annual mammography for at least 5 years.

MAIN OUTCOME MEASURES

The primary study end point was the predicted risk of death from breast cancer as estimated from the size, lymph node status and grade of the tumours diagnosed. This was compared with the control group from the UK Breast Screening Age Trial (Age Trial), adjusting for the different underlying incidence in the two populations.

RESULTS

As of December 2010, there were 165 breast cancers diagnosed in 37,025 person-years of observation and 30,556 mammographic screening episodes. Of these, 122 (74%) were diagnosed at screening. The cancers included 44 (27%) cases of ductal carcinoma in situ. There were 19 predicted deaths in 37,025 person-years in FH01, with an estimated incidence of 6.3 per 1000 per year. The corresponding figures for the Age Trial control group were 204 predicted deaths in 622,127 person-years and an incidence of 2.4 per 1000 per year. This gave an estimated 40% reduction in breast cancer mortality (relative risk = 0.60; 95% confidence interval 0.37 to 0.98; p = 0.04).

CONCLUSIONS

Annual mammography in women aged 40-49 years with a significant family history of breast or ovarian cancer is both clinically effective in reducing breast cancer mortality and cost-effective. There is a need to further standardise familial risk assessment, to research the impact of digital mammography and to clarify the role of breast density in this population.

TRIAL REGISTRATION

National Research Register N0484114809.

FUNDING

This project was funded by the NIHR Health Technology Assessment programme and will be published in full in Health Technology Assessment; Vol. 17, No. 11. See the HTA programme website for further project information.

The prognostic significance of early stage lymph node positivity in operable invasive breast carcinoma: number or stage

AIM

The earlier detection of breast cancer through mammographic screening has resulted in a shift in stage distribution with patients who are node-positive tending to present with a lower number of positive lymph nodes (LN). This study aims to assess the prognostic value of absolute number of positive nodes in the pN1 TNM stage (1-3 positive LN) and whether the prognostic value of the number of nodes in this clinically important stage justifies its consideration in management decisions.

METHODS

This study is based on a large and well-characterised consecutive series of operable breast cancer (3491 cases), treated according to standard protocols in a single institution, with a long-term follow-up.

RESULTS

LN stages and the absolute number of LN are associated with both breast cancer specific survival (BCSS) and distant metastasis free survival (DMFS). In the pN1 stage, patients with three positive LN (14% of pN1) show shorter BCSS (HR=1.9, (95% CI 1.3 to 2.6)) and shorter DMFS (HR=2.2, (95% CI 1.6 to 2.9)) when compared with one and/or two positive nodes. This effect is noted in the whole series as well as in different subgroups based on tumour size (pT1c and pT2), histological grade (grade 2 and 3), vascular invasion and oestrogen receptor status (both positive and negative). Multivariable analyses showed that three positive LN, compared with one and two positive LN, are an independent predictor of shorter BCSS and DMFS.

CONCLUSION

The number of LN in the pN1 stage yielded potentially informative risk assignments with three positive LN providing an independent predictor of poorer outcome.

The prognostic significance of lymphovascular invasion in invasive breast carcinoma

BACKGROUND

Although lymphovascular invasion (LVI) has been associated with a poor outcome in patients with breast cancer, it is not included in most internationally recognized staging systems, including the American Joint Committee on Cancer tumor, lymph node, metastasis (TNM) classification. This is mainly because it remains unclear whether the presence of LVI is an independent, high-risk criterion in clinically relevant staging subgroups.

METHODS

The current study was based on a large and well characterized consecutive series of patients who had operable (pathologic T1 [pT1]-pT2, pathologic N0 [pN0]-pN3, M0) breast cancer (3812 informative cases) who were treated according to standard protocols at a single institution and who had long-term follow-up to assess the prognostic value of definite LVI in clinically and molecularly relevant staging subgroups.

RESULTS

LVI was strongly associated with both breast cancer-specific survival (BCSS) and distant metastasis-free survival (DMFS) in the entire series and in different subgroups. Multivariate analyses identified LVI as an independent predictor of both BCSS and DMFS in patients with operable breast cancer overall; in the TNM clinical subgroups pT1a-pT1c/pN0 and pT2/pN0; and in the molecular classes estrogen receptor (ER)-positive, ER-negative, human epidermal growth factor 2 [HER2]-negative, and triple-negative. In patients who had lymph node-negative tumors, LVI could be used as a high-risk criterion providing survival disadvantage equivalent to that provided by 1 or 2 involved lymph nodes (pN0 to pN1) and to that provided by 1 size category (pT1 to pT2). The use of immunohistochemistry for detecting an endothelial-specific marker contributed to the prognostic significance of LVI when applied to routine LVI negative/possible cases.

CONCLUSIONS

LVI provided a strong predictor of outcome in patients with invasive breast cancer and should be incorporated into breast cancer staging systems.

The phospholipase C inhibitor U-73122 inhibits Ca(2+) release from the intracellular sarcoplasmic reticulum Ca(2+) store by inhibiting Ca(2+) pumps in smooth muscle

BACKGROUND AND PURPOSE

The sarcoplasmic reticulum (SR) releases Ca(2+) via inositol 1,4,5-trisphosphate receptors (IP(3)R) in response to IP(3)-generating agonists. Ca(2+) release subsequently propagates as Ca(2+) waves. To clarify the role of IP(3) production in wave generation, the contribution of a key enzyme in the production of IP(3) was examined using a phosphoinositide-specific phospholipase C (PI-PLC) inhibitor, U-73122.

EXPERIMENTAL APPROACH

Single colonic myocytes were voltage-clamped in whole-cell configuration and cytosolic Ca(2+) concentration ([Ca(2+)](cyto)) measured using fluo-3. SR Ca(2+) release was evoked either by activation of IP(3)Rs (by carbachol or photolysis of caged IP(3)) or ryanodine receptors (RyRs; by caffeine).

KEY RESULTS

U-73122 inhibited carbachol-evoked [Ca(2+)](cyto) transients. The drug also inhibited [Ca(2+)](cyto) increases, evoked by direct IP(3)R activation (by photolysis of caged IP(3)) and RyR activation (by caffeine), which do not require PI-PLC activation. U-73122 also increased steady-state [Ca(2+)](cyto) and slowed the rate of Ca(2+) removal from the cytoplasm. An inactive analogue of U-73122, U-73343, was without effect on either IP(3)R- or RyR-mediated Ca(2+) release.

CONCLUSIONS AND IMPLICATIONS

U-73122 inhibited carbachol-evoked [Ca(2+)](cyto) increases. However, the drug also reduced Ca(2+) release when evoked by direct activation of IP(3)R or RyR, slowed Ca(2+) removal and increased steady-state [Ca(2+)](cyto). These results suggest U-73122 reduces IP(3)-evoked Ca(2+) transients by inhibiting the SR Ca(2+) pump to deplete the SR of Ca(2+) rather than by inhibiting PI-PLC.

Tubular carcinoma of the breast: further evidence to support its excellent prognosis

PURPOSE Although tubular carcinoma (TC) is known to have a favorable prognosis, it is still unknown whether this subtype represents a distinct type of breast carcinoma or whether it behaves like other low-grade luminal A-type breast carcinomas. METHODS In this study, we performed a retrospective analysis of a large well-characterized series of breast cancers (2,608 carcinomas) to assess the clinicopathologic and molecular features and prognostic value of TC compared with grade 1 ductal carcinomas of the breast. Results When compared with grade 1 ductal carcinoma (n = 212), TC (n = 102) was more likely to be detected on mammographic screening, had smaller median size, and less frequently showed lymphovascular invasion. Compared with grade 1 ductal carcinoma, TC was associated with longer disease-free survival (chi(2) = 13.25, P < .001) and breast cancer-specific survival (chi(2) = 8.8, P = .003). In this study, none of the patients with TC developed distant metastasis or died from the disease without an intervening recurrence as invasive carcinoma of different histologic type. CONCLUSION We conclude that the biologic behavior of TC is excellent and is more favorable than that of grade 1 ductal carcinoma. Patients with TC may be at risk of developing second primary carcinomas in the contralateral breast, which may be of higher grade and poorer potential prognostic outcome. In addition, patients with TC seem to have a close to normal life expectancy, and as a consequence, adjuvant systemic therapy may not be justified in their routine management.

Factors associated with breast cancer-specific distress in younger women participating in a family history mammography screening programme

This multi-centre study examined factors associated with breast cancer-specific distress in 2321 women under 50 who are on a mammographic screening programme on account of their family history. Women were recruited from 21 UK centres, and completed a questionnaire one month before their screening appointment. The transactional theory of stress, appraisal, and coping provided the theoretical framework for the study. Factors measured included screening history, family history, perceived risk, cognitive appraisals, coping, optimism, and cancer worry. The findings indicate that the majority of women appraise their family history as being relevant and somewhat threatening to personal well-being, but something they can deal with emotionally. Acceptance was the most commonly used coping strategy. Hierarchical regression analysis identified that the factors most significantly associated with distress were an appraisal of high relevance and threat, increased risk perception, low dispositional optimism, and the use of both avoidant and task-orientated coping strategies. Women with children and those with relatives who have died from breast cancer were also more distressed. To conclude, most women appraised their situation positively but there is a potential profile of risk factors which may help clinicians identify those women who need extra psychological support as they progress through screening.

Turning subjective into objective: The BCCT.core software for evaluation of cosmetic results in breast cancer conservative treatment

Twelve expert observers from nine different countries convened in a workshop to evaluate the validity of the Breast Cancer Conservative Treatment. Cosmetic results (BCCT.core) software, an objective method for the aesthetic evaluation of breast cancer conservative treatment. Experts were initially asked to subjectively classify the aesthetic results of 30 photographed cases submitted to breast cancer conservative treatment according to the four-point Harris scale. It was pre-established that if at least two-thirds [Cardoso MJ, Cardoso J, Santos AC, Barros H, Oliveira MC. Interobserver agreement and consensus over the esthetic evaluation of conservative treatment for breast cancer. Breast 2005] of participants provided the same classification this would be considered a consensual evaluation for that case. For cases where such agreement was not reached, consensus was obtained using a nominal group technique. Experts then individually performed objective evaluation of the same set of photographs using the BCCT.core software. This provides an automatic rating of aesthetic results, once scale and reference points in the photograph have been chosen. Agreement between observers, between each observer and the consensus, for computer evaluation obtained by the different participants and between software and consensus was calculated using multiple kappa (k) and weighted kappa (wk) statistics. In the subjective assessment, first-round consensus was achieved in 17 (57%) cases. Overall interobserver agreement was fair to moderate (k=0.40, wk=0.57). In the objective assessment there was a higher level of concordance between participants (k=0.86, wk=0.90). Agreement between software and consensus classification was fair (k=0.34, wk=0.53), but was higher in the 17 cases that reached first-round consensus (k=0.60, wk=0.73). Merging the two middle classes of the Harris scale, to form a three-point scale, led to an improvement of all non-weighted measures of agreement. These results show that the BCCT.core software provides consistent evaluation of cosmesis. It has the potential to become a gold standard method for assessment of breast cosmesis in clinical trials, as it can be used simultaneously by a panel of observers from different parts of the world to provide more reliable assessments than has been possible previously.

Basal phenotype identifies a poor prognostic subgroup of breast cancer of clinical importance

BACKGROUND

Breast cancer is recognised to be a heterogeneous disease with a range of morphological appearances and behaviours. The recently recognised basal phenotype (BP) is associated with poor survival, but the clinical implications of this class of breast cancers remain to be adequately defined.

METHODS

We have examined a well-characterised series of 1872 invasive breast carcinomas with a long term follow-up to assess the clinical significance of BP.

RESULTS

A pragmatic definition of the BP as immunophenotypic evidence of basal cytokeratins CK5/6 and/or CK14 expression was used. These tumours were associated with shorter overall survival and disease-free interval in our series as a whole and in both the lymph node (LN) negative and LN positive subgroups. When stratified by histological grade, BP was of highly significant prognostic value in grade 3 but not in grades 1 or 2 tumours. Similarly, it was associated with poor survival in the moderate group of the Nottingham prognostic Index but not in the other groups. In a subgroup comprising LN negative grade 3 tumours, BP was the most powerful prognostic marker followed only by tumour size, while the other variables were non-significant. Patients with BP were more likely to respond to chemotherapy than those with non-basal tumours.

CONCLUSIONS

Our results provide robust evidence that BP is an important class of breast cancers with a particularly aggressive behaviour in patients with LN negative grade 3 disease. We recommend routine identification of BP in breast cancer and the development of effective adjuvant treatment strategies. These are important observations as these tumours typically lack hormone receptor and HER-2 overexpression limiting the range of relevant adjuvant therapies.

High-throughput protein expression analysis using tissue microarray technology of a large well-characterised series identifies biologically distinct classes of breast cancer confirming recent cDNA expression analyses

Recent studies on gene molecular profiling using cDNA microarray in a relatively small series of breast cancer have identified biologically distinct groups with apparent clinical and prognostic relevance. The validation of such new taxonomies should be confirmed on larger series of cases prior to acceptance in clinical practice. The development of tissue microarray (TMA) technology provides methodology for high-throughput concomitant analyses of multiple proteins on large numbers of archival tumour samples. In our study, we have used immunohistochemistry techniques applied to TMA preparations of 1,076 cases of invasive breast cancer to study the combined protein expression profiles of a large panel of well-characterized commercially available biomarkers related to epithelial cell lineage, differentiation, hormone and growth factor receptors and gene products known to be altered in some forms of breast cancer. Using hierarchical clustering methodology, 5 groups with distinct patterns of protein expression were identified. A sixth group of only 4 cases was also identified but deemed too small for further detailed assessment. Further analysis of these clusters was performed using multiple layer perceptron (MLP)-artificial neural network (ANN) with a back propagation algorithm to identify key biomarkers driving the membership of each group. We have identified 2 large groups by their expression of luminal epithelial cell phenotypic characteristics, hormone receptors positivity, absence of basal epithelial phenotype characteristics and lack of c-erbB-2 protein overexpression. Two additional groups were characterized by high c-erbB-2 positivity and negative or weak hormone receptors expression but showed differences in MUC1 and E-cadherin expression. The final group was characterized by strong basal epithelial characteristics, p53 positivity, absent hormone receptors and weak to low luminal epithelial cytokeratin expression. In addition, we have identified significant differences between clusters identified in this series with respect to established prognostic factors including tumour grade, size and histologic tumour type as well as differences in patient outcomes. The different protein expression profiles identified in our study confirm the biologic heterogeneity of breast cancer and demonstrate the clinical relevance of classification in this manner. These observations could form the basis of revision of existing traditional classification systems for breast cancer.

Development of a protocol for evaluation of mammographic surveillance services in women under 50 with a family history of breast cancer

BACKGROUND

Preliminary retrospective data suggest it is possible to identify impalpable breast cancer in women presenting with a family history of breast cancer under the age of 50, by using regular mammography. In consequence, this service is offered in a number of centres in the UK. The effectiveness of such a service, however, has not been fully evaluated.

METHODS

We propose to perform such an evaluation in a cohort of 20000 women under the age of 50 with a significant family history of breast cancer, given regular mammographic surveillance over 5 years. Comparison of surgical and pathological data with completed and ongoing population screening trials using analysis techniques of varying complexity will be performed to obtain an accurate prediction of future breast-cancer mortality reduction. The formal aims are: i) to estimate the difference in breast-cancer mortality in women under the age of 50 with a significant family history of breast cancer having regular mammography, compared with those not being screened; ii) to estimate the cost-effectiveness of regular mammography in this group of women, compared with no screening. The increase in health service resource use attributable to such a policy will be compared with no screening, and costed. Incremental cost-effectiveness ratios of implementing the standardised mammography strategy compared with no screening will be presented in terms of the additional cost per cancer detected, per life saved and per life-year saved.

Selective in vitro glycosylation of recombinant proteins: semi-synthesis of novel homogeneous glycoforms of human erythropoietin

BACKGROUND

A natural glycoprotein usually exists as a spectrum of glycosylated forms, where each protein molecule may be associated with an array of oligosaccharide structures. The overall range of glycoforms can have a variety of different biophysical and biochemical properties, although details of structure-function relationships are poorly understood, because of the microheterogeneity of biological samples. Hence, there is clearly a need for synthetic methods that give access to natural and unnatural homogeneously glycosylated proteins. The synthesis of novel glycoproteins through the selective reaction of glycosyl iodoacetamides with the thiol groups of cysteine residues, placed by site-directed mutagenesis at desired glycosylation sites has been developed. This provides a general method for the synthesis of homogeneously glycosylated proteins that carry saccharide side chains at natural or unnatural glycosylation sites. Here, we have shown that the approach can be applied to the glycoprotein hormone erythropoietin, an important therapeutic glycoprotein with three sites of N-glycosylation that are essential for in vivo biological activity.

RESULTS

Wild-type recombinant erythropoietin and three mutants in which glycosylation site asparagine residues had been changed to cysteines (His(10)-WThEPO, His(10)-Asn24Cys, His(10)-Asn38Cys, His(10)-Asn83CyshEPO) were overexpressed and purified in yields of 13 mg l(-1) from Escherichia coli. Chemical glycosylation with glycosyl-beta-N-iodoacetamides could be monitored by electrospray MS. Both in the wild-type and in the mutant proteins, the potential side reaction of the other four cysteine residues (all involved in disulfide bonds) were not observed. Yield of glycosylation was generally about 50% and purification of glycosylated protein from non-glycosylated protein was readily carried out using lectin affinity chromatography. Dynamic light scattering analysis of the purified glycoproteins suggested that the glycoforms produced were monomeric and folded identically to the wild-type protein.

CONCLUSIONS

Erythropoietin expressed in E. coli bearing specific Asn-->Cys mutations at natural glycosylation sites can be glycosylated using beta-N-glycosyl iodoacetamides even in the presence of two disulfide bonds. The findings provide the basis for further elaboration of the glycan structures and development of this general methodology for the synthesis of semi-synthetic glycoproteins.

The structure and growth of the statocyst in the Australian crayfish Cherax destructor

The morphology of the statocyst of the Australian crayfish Cherax destructor was examined using scanning electron microscopy. It resembles in general structure, size, and position the statocysts of crayfish described previously, and the size and distribution of the fields of setae on the floor of the capsule are similar but not the same. Over the size range examined, the relationship between the carapace length, the length of the basal antennular segment, the diameter of the statocyst capsule, and the total number of setae are all linear. The number and position of setae on the floor of the statocyst capsule were mapped for animals in two size classes (small, ca. 20 mm; large, ca. 50 mm) to test for changes in their arrangement during growth. The change in the ratio of setal number to statocyst size between the two size classes was about three times greater for the anterior setal field than for the other fields. We propose that differential development of the setal fields may be related to changes in the force-monitoring requirements of the animals as they increase in size, but this remains to be experimentally tested.

Eosinophil-mediated killing of Haemonchus contortus larvae: effect of eosinophil activation and role of antibody, complement and interleukin-5

Eosinophils have previously been shown to accumulate around the tissue invasive (L3) stage of sheep gastrointestinal parasites in vivo. In this study, eosinophils obtained from mammary washes of sheep, were shown to immobilize and kill H. contortus larvae in vitro in the presence of antibody specific against a defined L3 surface antigen. Eosinophils obtained from sheep primed by repeated infusion of H. contortus larvae were more effective than eosinophils obtained after a single infusion of parasite extract in Fasciola hepatica infected ewes suggesting the former were activated in vivo. The level of larval immobilization in the presence of antibody was significantly increased when complement was added to cultures containing activated eosinophils. The addition of interleukin-5 to larval cultures containing antibody and complement resulted in a significant increase in larval immobilization with unactivated eosinophils suggesting that eosinophil effector function is enhanced following priming with this cytokine. Ultrastructural analysis of the eosinophil/larvae interaction at 6 h of incubation revealed degranulation of adhering eosinophils onto the surface of larvae. By 24 h of incubation, many larvae showed signs of damage and most eosinophils had degenerated. These results suggest that eosinophil-mediated killing may be an effector mechanism for the elimination of L3 H. contortus larvae in immune sheep.

The role of the muscle receptor organ in the control of abdominal extension in the crayfish, Cherax destructor

A platform was lowered from beneath suspended crayfish, Cherax destructor, to evoke slow abdominal extension. The movements were filmed and the length between segments plotted as a function of time. Unlike abdominal flexion, which starts posteriorly and progresses anteriorly, extension occurs at all joints simultaneously. Although the duration of extension varied from trial to trial for an individual, the movement was organised in a stereotyped manner: the abdomen achieved a consistent position for any given proportion of the time for complete extension. We examined the role of the abdominal muscle receptor organs (MROs) in extension by cutting the nerves of selected MROs to abolish their input. The extension movement was measured before and after nerve section for animals with either unloaded or loaded abdomens. Removal of MRO input had no significant effect on extension of the unloaded abdomen. In animals with a loaded abdomen, the extension at joints spanned by sectioned MROs was slowed, whereas that at joints with intact MROs was not. The findings are consistent with the hypothesis that the MRO is an error detector in a servo-loop controlling abdominal position. The results provide the first demonstration that this load-compensating reflex loop operates during naturally evoked extension of the abdomen under constant load.

Serotonin immunoreactivity in the ventral nerve cord of the primitive crustacean Anaspides tasmaniae closely resembles that of crayfish

Syncarid crustaceans, of which only a few living species remain, have articulated segments with well-developed appendages along the length of the body, an arrangement thought to resemble that of the earliest malacostracan crustaceans. Decapod malacostracans have fused thoracic segments and reduced abdominal appendages. Modern representatives of the two groups are separated by at least 300 million years of evolutionary history. The serotonin immunoreactivity of ganglia and connectives from the ventral nerve cord of the syncarid Anaspides tasmaniae was compared with that of serially homologous ganglia of the crayfish Cherax destructor. Both species show the serotonin-immunoreactive longitudinal fibre bundles described from other decapods and thought to be part of a neuromodulatory network. They also have in common a number of the cell bodies associated with this system. Each species has some serotonergic cells in the region examined that are not present, or that do not stain, in the other species.

Demanding an answer to the world's needs

The whole world is wrestling with a gigantic equation. It is no less than that old balancing act called supply and demand. Other elements intrude to compound the equation, cost and resources among them. How to measure demand? Does not demand beg the question of need? Both are limitless.

Problems of a geriatric mental health service

The sub-speciality of geriatric psychiatry is coming to be known as “psycho-geriatrics”, an abbreviation which is not a very happy one, but which seems to be becoming generally accepted.