Mastitis and Mammary Abscess Management Audit (MAMMA) in the UK and Ireland

BACKGROUND

The aim of this multicentre prospective audit was to describe the current practice in the management of mastitis and breast abscesses in the UK and Ireland, with a specific focus on rates of surgical intervention.

METHODS

This audit was conducted in two phases from August 2020 to August 2021; a phase 1 practice survey and a phase 2 prospective audit. Primary outcome measurements for phase 2 included patient management pathway characteristics and treatment type (medical/radiological/surgical).

RESULTS

A total of 69 hospitals participated in phase 2 (1312 patients). The key findings were a high overall rate of incision and drainage (21.0 per cent) and a lower than anticipated proportion of ultrasound-guided aspiration of breast abscesses (61.0 per cent). Significant variations were observed regarding the rate of incision and drainage (range 0-100 per cent; P < 0.001) and the rate of needle aspiration (range 12.5-100 per cent; P < 0.001) between individual units. Overall, 22.5 per cent of patients were admitted for inpatient treatment, out of whom which 72.9 per cent were commenced on intravenous antibiotics. The odds of undergoing incision and drainage for a breast abscess or being admitted for inpatient treatment were significantly higher if patients presented at the weekend compared with a weekday (P ≤ 0.023). Breast specialists reviewed 40.9 per cent of all patients directly, despite the majority of patients (74.2 per cent) presenting within working hours on weekdays.

CONCLUSIONS

Variation in practice exists in the management of mastitis and breast abscesses, with high rates of incision and drainage in certain regions of the UK. There is an urgent need for a national best-practice toolbox to minimize practice variation and standardize patient care.

Geriatric Oncology as an Unmet Workforce Training Need in the United Kingdom-A Narrative Review by the British Oncology Network for Undergraduate Societies (BONUS) and the International Society of Geriatric Oncology (SIOG) UK Country Group

Cancer is a disease associated with ageing. Managing cancer in older adults may prove challenging owing to pre-existing frailty, comorbidity, and wider holistic needs, as well as the unclear benefits and harms of standard treatment options. With the ongoing advances in oncology and the increasing complexity of treating older adults with cancer, the geriatric oncology field must be a priority for healthcare systems in education, research, and clinical practice. However, geriatric oncology is currently not formally taught in undergraduate education or postgraduate training programmes in the United Kingdom (UK). In this commentary, we outline the landscape of geriatric oncology undergraduate education and postgraduate training for UK doctors. We highlight current challenges and opportunities and provide practical recommendations for better preparing the medical workforce to meet the needs of the growing population of older adults with cancer. This includes key outcomes to be considered for inclusion within undergraduate and postgraduate curricula.

Challenges in Geriatric Oncology—A Surgeon’s Perspective

As our global population ages, we will see more cancer diagnoses in older adults. Surgery is an important treatment modality for solid tumours, forming the majority of all cancers. However, the management of older adults with cancer can be more complex compared to their younger counterparts. This narrative review will outline the current challenges facing older adults with cancer and potential solutions. The challenges facing older adults with cancer are complex and include lack of high-level clinical trials targeting older adults and selection of the right patient for surgery. This may be standard surgical treatment, minimally invasive surgery or alternative therapies (no surgery) which can be local or systemic. The next challenge is to identify the individual patient’s vulnerabilities to allow them to be maximally optimised for treatment. Prehabilitation has been shown to be of benefit in some cancer settings but uniform guidance across all surgical specialties is required. Greater awareness of geriatric conditions amongst surgical oncologists and integration of geriatric assessment into a surgical clinic are potential solutions. Enhanced recovery programmes tailored to older adults could reduce postoperative functional decline. Ultimately, the greatest challenge an older adult with cancer may face is the mindset of their treating clinicians—a shared care approach between surgical oncologists and geriatricians is required.

EP.TH.275The role of amino acid transporters SLC1A5 and SLC3A2 in primary breast cancer in older women

Aims

Breast cancer in older women has more favourable biology, compared to younger women. Increased glutamine metabolism is a hallmark of cancer. The prognostic role of amino acid transporters involved with glutamine flux, SLC1A5 and SLC3A2, has been shown in breast cancer in younger women. This study aimed to investigate the role of SLC1A5 and SLC3A2 in breast cancer in older women as possible prognostic markers.

Methods

Surgical specimens were obtained from an existing series of 1,758 older women (≥70 years) with primary breast cancer, treated in a single institution with long-term (37+ years) follow-up. Of this cohort, 813 had primary surgical treatment. As part of previous work, it was possible to construct good quality tissue microarrays (TMAs) in 575 cases.

Immunohistochemical staining for SLC1A5 and SLC3A2 was performed. H-score was considered as a continuous variable as well as using positivity cut-offs of ≥ 45 for SLC1A5 and ≥15 for SLC3A2, using X-tile software.

Association between H-score and tumour size, grade, ER status, local-recurrence-free-survival (LRFS), overall survival (OS) and breast-cancer-specific-survival (BCSS) was investigated.

Results

No correlation was seen between neither marker and LRFS, OS, or BCSS in older women with breast cancer. Both markers were associated with high tumour grade and negative ER status (both p &lt; 0.001).

Conclusions

These findings are contrary to those found in younger women, where these amino acid transporters are associated with shorter BCSS. This may suggest that breast cancer in older women is less reliant on glutamine metabolism, which is consistent with an overall less aggressive phenotype.

The care of older cancer patients in the United Kingdom

The ageing population poses new challenges globally. Cancer care for older patients is one of these challenges, and it has a significant impact on societies. In the United Kingdom (UK), as the number of older cancer patients increases, the management of this group has become part of daily practice for most oncology teams in every geographical area. Older cancer patients are at a higher risk of both under- and over-treatment. Therefore, the assessment of a patient’s biological age and effective organ functional reserve becomes paramount. This may then guide treatment decisions by better estimating a prognosis and the risk-to-benefit ratio of a given therapy to anticipate and mitigate against potential toxicities/difficulties. Moreover, older cancer patients are often affected by geriatric syndromes and other issues that impact their overall health, function and quality of life. Comprehensive geriatric assessments offer an opportunity to identify and address health problems which may then optimise one’s fitness and well-being. Whilst it is widely accepted that older cancer patients may benefit from such an approach, resources are often scarce, and access to dedicated services and research remains limited to specific centres across the UK. The aim of this project is to map the current services and projects in the UK to learn from each other and shape the future direction of care of older patients with cancer.

Integrated Analysis of Key Differentially Expressed Genes Identifies DBN1 as a Predictive Marker of Response to Endocrine Therapy in Luminal Breast Cancer

Endocrine therapy is the mainstay of adjuvant treatment for patients with luminal breast cancer. Despite ongoing advances in endocrine therapy to date, a proportion of patients ultimately develop endocrine resistance, resulting in failure of therapy and poor prognosis. Therefore, as part of the growing concept of personalised medicine, the need for identification of predictive markers of endocrine therapy response at an early stage, is recognised. The METABRIC series was used to identify differentially expressed genes (DEGs) in term of response to adjuvant endocrine therapy. Drebrin 1 (DBN1) was identified as a key DEG associated with response to hormone treatment. Next, large, well-characterised cohorts of primary luminal breast cancer with long-term follow-up were assessed at the mRNA and protein levels for the value of DBN1 as a prognostic marker in luminal breast cancer, as well as its potential for predicting the benefit of endocrine therapy. DBN1 positivity was associated with aggressive clinicopathological variables and poor patient outcomes. Importantly, high DBN1 expression predicted relapse patients who were subject to adjuvant endocrine treatment. Our results further demonstrate that DBN1 is an independent prognostic marker in luminal breast cancer. Its association with the response to endocrine therapy and outcome provides evidence for DBN1 as a potential biomarker in luminal breast cancer, particularly for the benefit of endocrine treatment. Further functional investigations into the mechanisms underlying sensitivity to endocrine therapy is required.

Cytoplasmic cyclin E independently predicts recurrence in older patients with primary breast cancer

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Background: Primary breast cancer in the older ( > 70 years) population has distinct biological characteristics associated with favourable outcome, such as higher rate of estrogen receptor (ER) positivity. Due to comorbidities, older patients with primary breast cancer are more likely to die of non-breast cancer-related causes compared to their younger counterparts. Biomarkers that may influence treatment strategy therefore require interpretation in the specific biological and clinical context of older women. Cyclin E regulates cell cycle transition from G1 to S phase, and its deregulation is implicated in breast cancer pathogenesis. Tumour-specific isoforms of cyclin E localise to the cytoplasm. Expression of cytoplasmic cyclin E (c-cyclin E) is linked with poor clinical outcome. We now present multivariate analysis of breast cancer-specific survival (BCSS) by c-cyclin E and clinical markers of disease biology from a cohort of older women. The primary outcome, BCSS, excludes deaths from competing causes and is used as a surrogate for tumour biology. Methods: Between 1973 and 2010, 813 older women underwent initial surgery for early breast cancer and were followed up in a dedicated clinic in Nottingham. Excised tumours from 517 of these patients were successfully incorporated into a tissue microarray (TMA). Expression of c-cyclin E was assessed by IHC using an assay developed at MDACC, along with a panel of 24 biomarkers. Of these, ER, progesterone receptor (PR), human epidermal growth factor 2 (HER2) and Ki67 are in current clinical use and are analysed alongside c-cyclin E. Grade was assessed from the primary tumour. Multivariate analysis of BCSS was performed by Cox proportional hazard test. Results: In multivariate analysis alongside markers of disease biology currently used in the clinic (ER, PR, HER2, Ki67 and grade), c-cyclin E is the only factor that independently predicts BCSS in this cohort of older women (HR 5.0, 95% CI 2.1 – 12.0; p< 0.001). Conclusions: In the older population with primary breast cancer, c-cyclin E expression is the only independent biological marker of BCSS. Patients with low c-cyclin E expression are unlikely to die of breast cancer. These data have potential to influence treatment strategy in older patients. For example, patients with ER+, c-cyclin E negative disease plus multiple co-morbidities may be suitable for primary endocrine therapy. This hypothesis warrants prospective clinical evaluation.

Intensive care utilization and outcomes after high-risk surgery in Scotland: a population-based cohort study

BACKGROUND

The optimal perioperative use of intensive care unit (ICU) resources is not yet defined. We sought to determine the effect of ICU admission on perioperative (30 day) and long-term mortality.

METHODS

This was an observational study of all surgical patients in Scotland during 2005-7 followed up until 2012. Patient, operative, and care process factors were extracted. The primary outcome was perioperative mortality; secondary outcomes were 1 and 4 yr mortality. Multivariable regression was used to construct a risk prediction model to allow standard-risk and high-risk groups to be defined based on deciles of predicted perioperative mortality risk, and to determine the effect of ICU admission (direct from theatre; indirect after initial care on ward; no ICU admission) on outcome adjusted for confounders.

RESULTS

There were 572 598 patients included. The risk model performed well (c-index 0.92). Perioperative mortality occurred in 1125 (0.2%) in the standard-risk group (n=510 979) and in 3636 (6.4%) in the high-risk group (n=56 785). Patients with no ICU admission within 7 days of surgery had the lowest perioperative mortality (whole cohort 0.7%; high-risk cohort 5.3%). Indirect ICU admission was associated with a higher risk of perioperative mortality when compared with direct admission for the whole cohort (20.9 vs 12.1%; adjusted odds ratio 2.39, 95% confidence interval 2.01-2.84; P<0.01) and for high-risk patients (26.2 vs 17.8%; adjusted odds ratio 1.64, 95% confidence interval 1.37-1.96; P<0.01). Compared with direct ICU admission, indirectly admitted patients had higher severity of illness on admission, required more organ support, and had an increased duration of ICU stay.

CONCLUSIONS

Indirect ICU admission was associated with increased mortality and increased requirement for organ support.

TRIAL REGISTRATION

UKCRN registry no. 15761.

4th symposium on primary breast cancer in older women. Theme: putting personalized care into practice (Held: 3 March 2017)

Following the inception in 2010, the University of Nottingham hosted the 4th Symposium on Primary Breast Cancer in Older Women, under the auspices of the International Society of Geriatric Oncology, in March 2017, at East Midlands Conference Centre.  This is the only meeting of its kind in the UK, now held biennially, aiming at a multidisciplinary audience, including patients, their carers and advocates.  With a theme on ‘Putting personalising care into practice’, this Symposium included sessions on ‘local and systemic therapies’, ‘new ideas’, ‘patients and carers’, and ‘challenging areas’, covered by an international and local faculty, interviewing patients and carers, and abstract presentations.  Topics covered were practical and wide-ranging, including selectng for chemotherapy, radiotherapy and breast reconstruction, treating HER2-positive disease, and the roles of the geriatrician and geriatric oncology nurse.

Appearance of Powdery Mildew of Wheat Caused by Blumeria graminis f. sp. tritici on Pm17-Bearing Cultivars in North Carolina

Pm17 is a gene for resistance to powdery mildew caused by Blumeria graminis (DC.) E.O. Speer f. sp. tritici. The gene was first confirmed in the wheat-rye translocation cultivar Amigo (1). In Amigo, the translocation is T1AL-1RS and the 1RS arm has the gene Pm17. In the mid-Atlantic United States, at least two widely deployed soft red winter wheat (Triticum aestivum L.) cultivars, McCormick (2) and Tribute (3), possess Pm17 inherited from Amigo. Before 2009, low frequencies of mostly intermediate virulence to Pm17 were detected among isolates from research plots of highly susceptible cultivars (4), but Pm17-bearing cultivars remained immune to mildew in the field. In April 2009, moderately severe powdery mildew was observed for the first time throughout plots of McCormick, Tribute, and other cultivars in both Kinston and Raleigh, NC. At Kinston, Pm17 virulence was observed at two research sites, separated by approximately 10 km, throughout plots of Amigo, McCormick, Tribute, and the hard red winter wheat cultivar TAM 303, which also contains Pm17. In the same month, virulence to Pm17 was observed in Raleigh throughout rows and plots of Amigo and TAM 303. In Kinston and Raleigh, ratings of powdery mildew severity on the Pm17-containing cultivars were 4 or 5 on a scale of 0 to 9, with 0 being the absence of mildew pustules and 9 the most severe mildew infection. Mildew was observed on leaves of all ages. Mildewed leaves were collected from field plots of all four Pm17-bearing cultivars, and an assay to confirm Pm17 virulence was conducted in the laboratory. Mixed-isolate cultures were derived from the leaves and a detached-leaf assay was performed using Amigo, which is the standard Pm17 differential (4). All tested cultures were fully to moderately virulent on Pm17 and all were fully virulent on the susceptible control Chancellor. In the field, chasmothecia (sexual fruiting bodies) were observed on Pm17-bearing cultivars. Together with the quantitatively varying Pm17 virulence detected in the laboratory assay, this suggests that multiple strains of Pm17-virulent B. graminis f. sp. tritici may be present in the field, although that has not yet been demonstrated. Pm17 has protected wheat from powdery mildew over a substantial area in the mid-Atlantic United States. The loss of Pm17 is the most important virulence shift in the U.S. wheat powdery mildew population since Pm4a became ineffective around 2002. Isolates virulent to Pm17 can be expected to appear and multiply in wheat-producing states of the mid-Atlantic United States, including Delaware, Maryland, Virginia, North Carolina, South Carolina, and Georgia. Thus, the urgency of developing and releasing wheat cultivars with other sources of effective mildew resistance is heightened. References: (1) B. Friebe et al. Euphytica 91:59, 1996. (2) C. A. Griffey et al. Crop Sci. 45:416, 2005. (3) C. A. Griffey et al. Crop Sci. 45:419, 2005. (4) R. Parks et al. Plant Dis. 92:1074, 2008.

Guidelines on the management of common bile duct stones (CBDS)

The last 30 years have seen major developments in the management of gallstone-related disease, which in the United States alone costs over 6 billion dollars per annum to treat. Endoscopic retrograde cholangiopancreatography (ERCP) has become a widely available and routine procedure, whilst open cholecystectomy has largely been replaced by a laparoscopic approach, which may or may not include laparoscopic exploration of the common bile duct (LCBDE). In addition, new imaging techniques such as magnetic resonance cholangiography (MR) and endoscopic ultrasound (EUS) offer the opportunity to accurately visualise the biliary system without instrumentation of the ducts. As a consequence clinicians are now faced with a number of potentially valid options for managing patients with suspected CBDS. It is with this in mind that the following guidelines have been written.

The Objective Structured Clinical Examination and student collusion: marks do not tell the whole truth

OBJECTIVE

To determine whether the marks in the third year Objective Structured Clinical Examination (OSCE) were affected by the collusion reported by the students themselves on an electronic discussion board.

DESIGN

A review of the student discussion, examiners' feedback and a comparison of the marks obtained on the 2 days of the OSCE.

PARTICIPANTS

255 third year medical students.

SETTING

An OSCE consisting of 15 stations, administered on three sites over 2 days at a UK medical school.

RESULTS

40 students contributed to the discussion on the electronic discussion board. The main points raised were perceived inequity between students who did, or did not, have prior knowledge of the station content, and the lack of honesty and professionalism of their peers. Most contributors claimed to have received, or knew of others receiving, prior knowledge, but none confessed to passing on information. No significant difference (p = 0.16) was observed in the overall mark for the OSCE on day 1 (mean 390 (SD 37)) and day 2 (mean 397 (38)). On day 2, marks were considerably greater for four stations and markedly lower for three stations. It was not obvious why collusion should affect these station marks. A clear indication of the effects of collusion could only be obtained from a single subsection of an individual station (pathology) where 82 students on day 2 incorrectly gave the diagnosis from day 1.

CONCLUSION

Marks do not provide a sound inference of student collusion in an OSCE and may mask the aspects of professional development of students.

Improvement in activities of daily living in elderly following treatment for post-bereavement depression

OBJECTIVE

To determine if elderly bereaved depressed subjects display difficulty with activities of daily living (ADL) and if their ADL difficulty improves with psychopharmacologic intervention.

METHOD

The Assessment of Motor and Process Skills (AMPS), an ADL assessment measuring ADL motor and ADL process skills, was administered to a pilot sample of elderly persons with post-bereavement depression prior to psychopharmacologic intervention and subsequently during treatment response.

RESULTS

In the pretreatment phase, subjects displayed difficulty with ADL motor and ADL process skills that significantly improved during the treatment response phase.

CONCLUSION

Results suggest that elderly bereaved depressed individuals demonstrated ADL difficulty that responds positively to psychopharmacologic intervention.

Development of a FLP/frt system for generating helper-dependent adenoviral vectors

Helper-dependent (HD) adenoviral vectors devoid of all viral coding sequences have a large cloning capacity and have been reported to provide long-term transgene expression in vivo with negligible toxicity, making them attractive vectors for gene therapy. Currently, the most efficient means of generating HD vectors involves co-infecting 293 cells expressing Cre with the HD vector and a helper virus bearing a packaging signal flanked by loxP sites. Cre-mediated excision of the packaging signal renders the helper virus genome unpackageable but still able to replicate and to provide helper functions for HD vector propagation. HD vector titer is increased by serial co-infections. Typically, helper virus contamination is < or =1% pre- and < or =0.1% postpurification by CsCl banding. While these contamination levels are low, further reduction is desirable. Alternative methods of selection against the helper virus may achieve this goal, especially when combined with Cre/loxP. We describe the development of a system for generating HD vectors based on site-specific recombination between frt sites catalyzed by FLP recombinase and show by direct comparison that the FLP/frt and Cre/loxP systems are equivalent with respect to HD vector amplification efficiency and helper virus contamination levels. Availability of a second recombinase system for HD vector production will enhance the utility and flexibility of HD vectors.

Characterization and mechanisms of chromosomal alterations induced by benzene in mice and humans

Elevated frequencies of chromosomal aberrations have been observed in the lymphocytes of benzene-exposed workers. Similar changes occurring in the bone marrow may play an important role in the development of leukemia. The objective of this research has been to characterize chromosomal alterations induced by benzene in mice and humans and to investigate the potential role of inhibition of topoisomerase II in the myelotoxic effects of benzene. The research is presented in three sections corresponding to the specific aims of the project: genotoxicity studies in the mouse, topoisomerase II studies, and initial studies using a new fluorescence in situ hybridization (FISH) approach to detect chromosome alterations in benzene-exposed workers. The results of the mouse experiments indicate that both chromosome breakage and aneuploidy are induced in the bone marrow of B6C3F1 mice following benzene administration. Chromosome breakage is the predominant effect, and this occurs primarily in the mouse euchromatin. Significant breakage within the mouse heterochromatin was also observed, as was aneuploidy. Breakage in the mouse bone marrow erythrocytes increased as a function of both dose and duration of benzene administration. The aneuploidy resulting from benzene exposure in mice was a relatively infrequent event, with increases of both chromosome loss and hyperdiploidy being observed. In the topoisomerase studies, benzene or its metabolites were shown to inhibit topoisomerase II enzyme activity in an isolated enzyme system, in a human bone marrow-derived leukemia cell line, and in vivo in the bone marrow of treated mice. The decreased activity was probably due to the rapid degradation of the topoisomerase II protein in the treated cells. In the human biomonitoring studies, the feasibility of using FISH with tandem DNA probes to detect chromosome alterations in interphase granulocytes and lymphocytes of benzene-exposed workers was demonstrated. The results from the two worker studies were somewhat inconsistent, however. In the study of Estonian workers, characterized by lower exposures and a smaller sample size, the benzene-exposed workers exhibited elevated frequencies of breakage in the lq12 region as compared with those seen in controls. A suggestive trend toward increased hyperdiploidy was also seen, although the frequencies in the exposed workers were low and within the range of our laboratory's historical control frequencies. In the larger study of more highly exposed Chinese workers, no increase in breakage affecting the 1q12 region was seen among the exposed workers. A trend toward increased hyperdiploidy of chromosome 1 was seen in the exposed workers when the concentration of urinary benzene metabolites was used in conjunction with the frequency of hyperdiploidy observed in the lymphocytes of the individual workers. The results of these studies indicate that benzene exposure is characterized by chromosome breakage, primarily within the euchromatin, and modest increases in aneuploidy. These findings also provide the first direct evidence that benzene is capable of inhibiting the enzymatic activity of topoisomerase II in vivo, providing additional support for the hypothesis that inhibition of topoisomerase II contributes to benzene-induced toxicity and leukemogenesis.

Adolescents in the age of AIDS: myths, misconceptions, and misunderstandings regarding sexually transmitted diseases

The purpose of this study is twofold: to evaluate the extent of knowledge possessed by young people residing in an urban sexually transmitted disease (STD) and AIDS epicenter about STDs, including AIDS; and to determine whether knowledge levels varied by age, gender, race/ ethnicity, and/or previous health instruction. A total of 867 adolescents (472 females and 395 males) attending a large public high school in New York City completed a self-administered survey. Levels of knowledge about AIDS transmission and prevention were high (mean percentage correct = 91.8%). Nonetheless, adolescent respondents locked awareness about the prevalence of common STDs, had limited understanding of the ways in which these diseases can be transmitted and prevented, and were unaware of potentially serious sequelae resulting from exposure to infectious agents (e.g., infertility from chlamydial infections). Young people who had taken a health education course in which STDs were discussed did slightly better on the knowledge survey than did their peers. While the prevention of HIV infection is, and should be, a national priority, more concerted efforts are needed to better educate young people about other STDs in the overall context of sexual health.

Institutional variability in red blood cell conservation practices for coronary artery bypass graft surgery. Institutions of the MultiCenter Study of Perioperative Ischemia Research Group

OBJECTIVE

To assess whether substantial institutional variability exists in red blood cell conservation practices associated with coronary artery bypass graft (CABG) surgery.

DESIGN

Prospective, randomized patient enrollment and data collection.

SETTING

Twenty-four U.S. academic institutions participating in the Multicenter Study of Perioperative Ischemia.

PARTICIPANTS

A well-defined subset of primary CABG surgery patients (n = 713) expected to be at low risk for bleeding and exposure to allogeneic transfusion.

INTERVENTIONS

None (observational study).

MEASUREMENTS AND MAIN RESULTS

Frequency of use of red blood cell conservation techniques was determined among institutions. Correlation was determined between use of each technique and transfusion of allogeneic red blood cells and between use of each technique and median institutional blood loss. Significant variability (p < 0.01) was detected in institutional transfusion practice with respect to the use of predonated autologous whole blood, normovolemic hemodilution, red cell salvage, and reinfusion of shed mediastinal blood. The frequency of institutional use of these techniques was not associated with allogeneic transfusion (r2 < 0.15) or blood loss (r2 < 0.10) in the low-risk population of patients examined.

CONCLUSIONS

Institutions vary significantly in perioperative blood conservation practices for CABG surgery. Further study to determine the appropriate use of these techniques is warranted.

Chromosome damage and aneuploidy detected by interphase multicolour FISH in benzene-exposed shale oil workers

A multicolour tandem-labelling fluorescence in situ hybridization (FISH) procedure was used to detect chromosome alterations in peripheral blood cells of a group of Estonian petrochemistry workers. Twelve workers employed in benzene production and five cokery workers, together with eight unexposed rural controls, were enrolled in the study. The methodology employed, based on the in situ hybridization of adjacent centromeric and pericentromeric regions, allowed the simultaneous detection of both chromosome breakage, involving damage-prone pericentromeric regions, and hyperploidy in interphase cells. Blood smears from all subjects were hybridized with chromosome 1 specific probes, in order to detect genotoxic damage in circulating lymphocytes and granulocytes. Moreover, lymphocyte cultures were established, harvested 48 h following mitogen stimulation and hybridized with the tandem chromosomes 1 and 9 probes. No significant difference in the incidence of breakage was detected in the nucleated cells of blood smears of exposed vs. control subjects. In contrast, modest but significantly increased frequencies of breakage affecting both chromosomes 1 and 9 were observed in the cultured lymphocytes of the benzene-exposed workers compared to the unexposed controls, suggesting an expression of premutagenic lesions during the S-phase in vitro. Across the entire study group, the frequencies of breakage affecting chromosomes 1 and 9 in the stimulated lymphocytes were highly intercorrelated (p < 0.001). No significant difference was found in the incidence of hyperploidy among the study groups, although a tendency to higher values was observed in benzene-exposed workers. Although the relatively small size of the study groups does not allow firm conclusions on the role of occupational exposure, the observed patterns are suggestive of effects in the benzene-exposed workers. This work also shows that tandem labelling FISH can be usefully applied in human biomonitoring, allowing the simultaneous detection of both hyperploidy and chromosome breakage at interphase in different cell types.

Use of helper-dependent adenoviral vectors of alternative serotypes permits repeat vector administration

We have developed a new helper adenovirus (Ad) based on serotype 2, Ad2LC8cCARP, for use in the Cre/loxP system (Parks et al. Proc Natl Acad Sci USA, 1996; 93: 13565-13570) to generate Ad vectors deleted of all protein coding sequences (helper-dependent Ad vectors (hdAd)). A comparison of Ad2LC8cCARP and our original helper virus (based on serotype 5, Ad5LC8cluc) showed that the two helper viruses amplified hdAd with a similar efficiency, and resulted in a similar yield and purity after large-scale preparation of vector. In vitro, the resulting hdAd2 had a similar transduction efficiency and expression kinetics of transgene (beta-gal) as the hdAd5. An important feature of the helper-dependent system is that all virion components, except the virion DNA, derive from the helper virus. Consequently, vectors produced with help from Ad2LC8cCARP were not neutralized by antibodies against Ad5, and vectors produced with Ad5 helper were resistant to neutralizing antibodies against Ad2. Analysis of transgene expression in mouse liver after intravenous injection of the Ad2-based hdAd showed that the vector could efficiently transduce the liver, and produce high levels of a foreign transgene, similar to those expressed by the hdAd generated with the Ad5 helper virus. Mice immunized with hdAd2 produced Ad2-neutralizing antibodies, which did not cross-react with hdAd5. To determine if successful repeat Ad vector administration could be achieved by sequential use of alternative Ad serotypes, we injected mice with hdAd2 (hSEAP) followed 3 months later by a lacZ-expressing hdAd of either the same or different serotype. Repeated administration of hdAd2 resulted in a 30- to 100-fold reduction in transgene expression compared with naive animals. In contrast, no decrease in transgene expression was observed when the second vector was of a different serotype. These results demonstrate that effective vector readministration can be achieved by the sequential use of hdAds based on alternative serotypes.

Safety and efficacy of shed mediastinal blood transfusion after cardiac surgery: a multicenter observational study. Multicenter Study of Perioperative Ischemia Research Group

OBJECTIVE

To examine the efficacy and safety of shed mediastinal blood (SMB) transfusion in preventing allogenic red blood cell (RBC) transfusion.

DESIGN

An observational clinical study.

SETTING

Twelve US academic medical centers.

PARTICIPANTS

Six hundred seventeen patients undergoing elective primary coronary artery bypass grafting.

INTERVENTIONS

Patients were administered SMB transfusion or not, according to institutional and individual practice, without random assignment.

MEASUREMENTS AND RESULTS

The independent effect of SMB transfusion on postoperative RBC transfusion was examined by multivariable modeling. Potential complications of SMB transfusion, such as bleeding and infection, were examined. Three hundred twelve of the study patients (51%) received postoperative SMB transfusion (mean volume, 554 +/- 359 mL). Patients transfused with SMB had significantly lower volumes of RBC transfusion than those not receiving SMB (0.86 +/- 1.50 v 1.08 +/- 1.65 units; p < 0.05). However, multivariable analysis showed that SMB transfusion was not predictive of postoperative RBC transfusion. Demographic factors (older age, female sex), institution, and postoperative events (greater chest tube drainage, lower hemoglobin level on arrival to the intensive care unit, and use of inotropes) were significant predictors of RBC transfusion. The volume of chest tube drainage on the operative day (707 +/- 392 v 673 +/- 460 mL; p = 0.30), reoperation for hemorrhage (3.1% v2.5%; p = 0.68), and overall frequency of infection (5.8% v 6.6%; p = 0.81) were similar between patients receiving and not receiving SMB, respectively. However, in patients who did not receive allogenic RBC transfusion, there was a significantly greater frequency of wound infection in the SMB group (3.6% v0%; p = 0.02).

CONCLUSION

These data suggest that SMB is ineffective as a blood conservation method and may be associated with a greater frequency of wound infection.

Preoperative serum potassium levels and perioperative outcomes in cardiac surgery patients. Multicenter Study of Perioperative Ischemia Research Group

CONTEXT

Although potassium is critical for normal electrophysiology, the association between abnormal preoperative serum potassium level and perioperative adverse events such as arrhythmias has not been examined rigorously.

OBJECTIVE

To determine the prevalence of abnormal preoperative serum potassium levels and whether such abnormal levels are associated with adverse perioperative events.

DESIGN AND SETTING

Prospective, observational, case-control study of data collected from 24 diverse US medical centers in a 2-year period from September 1, 1991, to September 1, 1993.

PATIENTS

A total of 2402 patients (mean [SD] age, 65.1 [10.3] years; 24% female) undergoing elective coronary artery bypass grafting who were not enrolled in another protocol. The study population was identified using systematic sampling of every nth patient, in which n was based on expected total number of procedures at that center during the study period.

MAIN OUTCOME MEASURES

Intraoperative and postoperative arrhythmias, the need for cardiopulmonary resuscitation (CPR), cardiac death, and death due to any cause prior to discharge, by preoperative serum potassium level.

RESULTS

Perioperative arrhythmias occurred in 1290 (53.7%) of 2402 patients, with 238 patients (10.7%) having intraoperative arrhythmias, 329 (13.7%) having postoperative nonatrial arrhythmias, and 865 (36%) having postoperative atrial flutter or fibrillation. The incidence of adverse outcomes was 3.6% for death, 2.0% for cardiac death, and 3.5% for CPR. Serum potassium level less than 3.5 mmol/L was a predictor of serious perioperative arrhythmia (odds ratio [OR], 2.2; 95% confidence interval [CI], 1.2-4.0), intraoperative arrhythmia (OR, 2.0; 95% CI, 1.0-3.6), and postoperative atrial fibrillation/flutter (OR, 1.7; 95% CI, 1.0-2.7), and these relationships were unchanged after adjusting for confounders. The significant univariate association between increased need for CPR and serum potassium level less than 3.3 mmol/L (OR, 3.3; 95% CI, 1.2-9.5) and greater than 5.2 mmol/L (OR, 3.0; 95% CI, 1.1-8.7) became nonsignificant after adjusting for confounders.

CONCLUSIONS

Perioperative arrhythmia and the need for CPR increased as preoperative serum potassium level decreased below 3.5 mmol/L. Although interventional trials are required to determine whether preoperative intervention mitigates these adverse associations, preoperative repletion is low cost and low risk, and our data suggest that screening and repletion be considered in patients scheduled for cardiac surgery.

Gut barrier dysfunction in obstructive jaundice. The Purce Lecture 1997

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Variability in transfusion practice for coronary artery bypass surgery persists despite national consensus guidelines: a 24-institution study. Institutions of the Multicenter Study of Perioperative Ischemia Research Group

BACKGROUND

An estimated 20% of allogeneic blood transfusions in the United States are associated with cardiac surgery. National consensus guidelines for allogeneic transfusion associated with coronary artery bypass graft (CABG) surgery have existed since the mid- to late 1980s. The appropriateness and uniformity of institutional transfusion practice was questioned in 1991. An assessment of current transfusion practice patterns was warranted.

METHODS

The Multicenter Study of Perioperative Ischemia database consists of comprehensive information on the course of surgery in 2,417 randomly selected patients undergoing CABG surgery at 24 institutions. A subset of 713 patients expected to be at low risk for transfusion was examined. Allogeneic transfusion was evaluated across institutions. Institution as an independent risk factor for allogeneic transfusion was determined in a multivariable model.

RESULTS

Significant variability in institutional transfusion practice was observed for allogeneic packed red blood cells (PRBCs) (27-92% of patients transfused) and hemostatic blood components (platelets, 0-36%; fresh frozen plasma, 0-36%; cryoprecipitate, 0-17% of patients transfused). For patients at institutions with liberal rather than conservative transfusion practice, the odds ratio for transfusion of PRBCs was 6.5 (95% confidence interval [CI], 3.8-10.8) and for hemostatic blood components it was 2 (95% CI, 1.2-3.4). Institution was an independent determinant of transfusion risk associated with CABG surgery.

CONCLUSIONS

Institutions continue to vary significantly in their transfusion practices for CABG surgery. A more rational and conservative approach to transfusion practice at the institutional level is warranted.

Dose-response studies of the induction of hyperdiploidy and polyploidy by diethylstilbestrol and 17beta-estradiol in cultured human lymphocytes using multicolor fluorescence in situ hybridization

Diethylstilbestrol (DES) and 17beta-estradiol (E2) are known inducers of aneuploidy and polyploidy in vivo and in vitro. Isolated human lymphocytes were treated with the stilbene estrogen DES (0.05-50 microM) and the steroid estrogen E2 (0.05-75 microM) in culture. Multicolor fluorescence in situ hybridization (FISH) with DNA probes for the centromere and adjacent heterochromatin regions of chromosomes 1, 9, and 16 was used to detect hyperdiploidy, polyploidy, and chromosomal breakage affecting these chromosomes. Using this FISH technique, significant nonlinear increases in hyperdiploidy were observed with both compounds, whereas no induction of chromosomal breakage affecting the pericentric heterochromatin regions of chromosomes 1, 9, and 16 could be detected. DES induced a maximum of approximately 13% hyperdiploid cells at 30 microM, whereas E2 showed its highest induction at 75 microM with 7% hyperdiploid cells. To distinguish hyperdiploidy from polyploidy, a FISH labeling strategy to detect multiple chromosomes simultaneously was established. Using this approach, we could show that most of the cells showing multiple hybridization regions after treatment with both chemicals were most likely the result of polyploidy rather than true hyperdiploidy. These results indicate that the induction of hyperdiploidy/polyploidy with DES and E2 show sublinear dose-response relationships with likely threshold concentrations in human lymphocytes and that FISH with multiple probes targeting different chromosomes can be used to estimate hyperdiploidy and polyploidy frequencies.

Role of the gut in the pathophysiology of extrahepatic biliary obstruction

BACKGROUND

Gram negative septic events are the commonest source of morbidity and mortality as a result of surgery in jaundiced patients. The large intestine provides the major source of Gram negative bacteria in mammals and is implicated in the pathogenesis of systemic endotoxaemia in obstructive jaundice. Bile salts have an important part in maintaining indigenous microecological homeostasis through their emulsifying properties.

AIMS

The aim was to investigate the effects of biliary obstruction and isolated external biliary diversion on gastro-intestinal structure and caecal bacterial flora in relation to bacterial translocation.

METHOD

Six groups of adult male Wistar rats were studied (no operation, sham operated, and bile duct ligated (BDL) for one and three weeks and a choledocho-vesical fistula (CDVF) for one week). At the end of the study period plasma was assayed for evidence of endotoxaemia and the animals were tested for bacterial translocation to the mesenteric lymph node complex (MLNC), liver, lungs, and spleen. Quantitative and qualitative bacteriological studies were performed on the caecal contents and segments of colon and terminal ileum were washed and prepared for histological assessment.

RESULTS

Bacterial translocation was significantly increased in the BDL1 (68.8%) and BDL3 (60%) groups compared with the sham1 (6.3%), sham3 (9.1%), No operation (0%), and CDVF1 (16.7%) groups. Although translocation was more pronounced in the BDL1 group, this was almost exclusively to the MLNC compared with the more widespread translocation to other organs in the BDL3 group. The BDL3 group was the only group with significantly raised concentrations of endotoxin and anticore glycolipid. The caecal Gram negative aerobic counts were significantly increased in the BDL1 and CDVF1 groups compared with all other groups. There was evidence of structural abnormalities in the terminal ileum of rats jaundiced for three weeks, but not in the other groups.

CONCLUSIONS

Biliary obstruction for one and three weeks promotes bacterial translocation although the mechanisms may be different. Absence of intralumenal bile results in a significant but self limiting increase in the Gram negative aerobic population, which may account for translocation in the early stages of biliary obstruction. As the duration of biliary obstruction increases systemic endotoxaemia is a consistent feature which, combined with factors such as immunological depression and physical disruption of gut barrier function, may promote bacterial translocation perpetuating systemic sepsis.

Atrial fibrillation following coronary artery bypass graft surgery: predictors, outcomes, and resource utilization. MultiCenter Study of Perioperative Ischemia Research Group

OBJECTIVE

To determine the incidence, predictors, and cost of atrial fibrillation and flutter (AFIB) following coronary artery bypass graft (CABG) surgery.

DESIGN

Prospective observational study (MultiCenter Study of Perioperative Ischemia).

SETTING

Twenty-four university-affiliated hospitals in the United States from 1991 to 1993.

SUBJECTS

A total of 2417 patients undergoing CABG with or without concurrent valvular surgery selected using a systematic sampling interval.

MEASUREMENTS

Detailed preoperative, intraoperative, and postoperative data collected on standardized reporting forms.

RESULTS

The overall incidence of postoperative AFIB was 27 percent. Independent predictors of postoperative AFIB included advanced age (odds ratio [OR], 1.24 per 5-year increase; 95 percent confidence interval [CI], 1.18-1.31); male sex (OR, 1.41; 95 percent CI, 1.09-1.81); a history of AFIB (OR, 2.28; 95 percent CI, 1.74-3.00); a history of congestive heart failure (OR, 1.31; 95 percent CI, 1.04-1.64); and a precardiopulmonary bypass heart rate of more than 100 beats per minute (OR, 1.59; 95 percent CI, 1.00-2.55). Surgical practices such as pulmonary vein venting (OR, 1.44; 95 percent CI, 1.13-1.83); bicaval venous cannulation (OR, 1.40; 95 percent CI, 1.04-1.89); postoperative atrial pacing (OR, 1.27; 95 percent CI, 1.00-1.62); and longer cross-clamp times (OR, 1.06 per 15 minutes; 95 percent CI, 1.00-1.11) also were identified as independent predictors of postoperative AFIB. Patients with postoperative AFIB remained an average of 13 hours longer in the intensive care unit and 2.0 days longer in the ward when compared with patients without AFIB.

CONCLUSION

Postoperative AFIB is common after CABG surgery and has a significant effect on both intensive care unit and overall hospital length of stay. In addition to expected demographic factors, certain surgical practices increase the risk of postoperative AFIB. Randomized controlled trials are necessary to determine if modification of these surgical practices, especially in patients at high risk, would decrease the incidence of postoperative AFIB.

SFV topoisomerase: sequence specificity in a genetically mapped interval

Poxviral DNA topoisomerases are sequence-specific enzymes whose activities are thought to influence such diverse processes as transcription, DNA replication, and genetic recombination. To obtain further insights into the relatedness of these enzymes, and their influence on virus-mediated recombination, we have determined the target-specificity and other catalytic properties of the Shope fibroma virus (SFV) topoisomerase. SFV topoisomerase was expressed in Escherichia coli and purified as a glutathione S-transferase (GST) or (his)6-tagged fusion protein. The recombinant Leporipox-virus (SFV) enzyme displayed catalytic properties very similar to vaccinia topoisomerase. In particular SFV topoisomerase recognizes the same pentanucleotide motif [5'-(C/T)CCTT-3'] and promotes the same DNA relaxation, strand transfer, and strand cleavage reactions catalyzed by the Orthopoxviral (vaccinia) enzyme. The SFV enzyme can also efficiently cleave DNA 3' of the variant site 5'-CCCTG-3' in certain sequence contexts. These studies identified several sites where SFV topoisomerases interact with a recombinational substrate and permitted a comparison of recombination frequencies across intervals which did, or did not, span these sites. We failed to detect any effect of topoisomerase-recognition sites on recombination frequencies, except for a small (< 2-fold) stimulation seen when the substrates encoded a nearby poxviral promoter. This and other work shows that poxviral topoisomerases from several genera share common target specificities, but other enzymatic systems probably catalyze the high-frequency recombination seen in poxvirus-infected cells.

Comparison of the Standard Combined (Bidirectional) Radial Keratotomy Technique With the Undercut Technique in Human Donor Eyes

BACKGROUND

We evaluated the efficacy of a new radial keratotomy technique, using a diamond designed to undermine the central clear zone without incising superficial stroma.

METHODS

An 8-incision radial keratotomy at a 3-mm central clear zone was performed on nine pairs of human donor globes. One eye of each pair was incised using the standard combined (bidirectional) technique diamond and the contralateral eye, using the undercut bidirectional technique diamond. Paired t-tests were used to compare changes in central corneal curvature between these two groups. Microscopic analysis of incision morphology was performed on four eyes.

RESULTS

Corneal topography at the 1-, 3-, and 5-mm annular zones revealed corneal flattening of 7.70 +/- 1.50 diopters (D), 6.70 +/- 1.30 D, and 5.10 +/- 1.00 D, respectively, in the undercut bidirectional technique group versus 6.20 +/- 1.70 D, 5.30 +/- 1.50 D, and 4.00 +/- 1.20 D, respectively, in the standard bidirectional technique group (P < 0.01 for each annular zone). Light microscopy (serial sections) revealed an average incision depth of 80.9 +/- 3.9% in the undercut bidirectional technique group versus 72.7 +/- 4.5% in the combined group (P < 0.01). The undercut bidirectional technique incisions undermined the central clear zone for a distance of approximately 350 microns compared to about 140 microns for the standard bidirectional incisions.

CONCLUSIONS

In the human cadaver eye, the undercut technique of radial keratotomy provided greater flattening than the standard bidirectional technique. The greater amount of flattening may result from greater central extension of the undercut incisions beneath the central clear zone, from greater incision depth, or from a combination of both factors.

Alterations in brain phosphate metabolite concentrations in patients with human immunodeficiency virus infection

Human immunodeficiency virus (HIV)-infected individuals often demonstrate neuropsychiatric impairment; however, it is unclear how brain metabolism may be altered in such patients. We used in vivo phosphorus 31 magnetic resonance spectroscopy to noninvasively assess brain energy and phospholipid metabolism by measuring brain concentrations of adenosine triphosphate (ATP), phosphocreatine (PCr), and inorganic phosphate (Pi), as well as phospholipid compounds and intracellular pH. In study 1, 17 HIV-seropositive men with varying degrees of neuropsychiatric impairment and six control subjects were studied. Localized spectra were obtained from a heterogeneous 5 x 5 x 5-cm volume of interest (VOI). Patients with HIV infection had a significantly lower ATP/Pi ratio and a trend for a lower PCr/Pi ratio than did the control group. In addition, the ATP/Pi and PCr/Pi ratios were both significantly negatively correlated with overall severity of neuropsychiatric impairment. In study 2, three HIV-seropositive men with neuropsychiatric impairment were compared with 11 HIV-seronegative men. Localized phosphorus 31 magnetic resonance spectra were obtained from two relatively homogeneous VOIs: (1) a predominantly white matter VOI, and (2) a predominantly subcortical gray matter VOI. The three HIV-infected patients demonstrated significantly decreased ATP and PCr concentrations in the white matter VOI. These results suggest that HIV infection of the brain may impair brain cellular oxidative metabolism and that the degree of metabolic compromise may be related to the severity of neuropsychiatric impairment.