Regular follow-up with cervical cytology is of questionable value following surgical treatment of microinvasive cervical cancer

OBJECTIVES

To assess the follow-up smears and their outcomes of patients with conservatively managed early-stage cervical cancer as per UK guidelines within our service. To evaluate whether intensive follow-up can detect pre-cancer early compared to the standard 3 yearly follow-up.

STUDY DESIGN

Retrospective review.

METHODS

All patients treated for early stage (stage 1A1 and 1A2) with cervical cancer from 01/2002 to 01/2020 at University Hospitals of Derby and Burton were included. Patients who had initial hysterectomy were excluded from our analysis. Review conducted using electronic patient records for treatment, histology, and follow-up smears. Number of abnormal follow-up smears and number of recurrent cervical cancers were considered the main outcome measures.

RESULTS

98 cases were identified. 81 (82.65 %) were stage 1A1 and 17 (17.35 %) were stage 1A2. 74 (75.51 %) patients had squamous histology and 24 (24.49 %) had adenocarcinomas. Median follow-up was 11.08 years (4043 days). 510 follow-up smears were performed, of which 33 (6.47 %) were abnormal. 5 of these abnormal smears showed low grade dyskaryosis (0.98 %) and 2 smears showed high grade dyskaryosis (0.39 %). The positive predictive value of follow-up smears to detect pre-cancerous changes was 5.71 %. There were no recurrent cancers detected.

CONCLUSIONS

Microinvasive cervical cancer is effectively managed with conservative surgery. There were no recurrent cancers detected in our cohort during follow-up and there were only 2 high grade dyskaryoses detected (n = 2/510, 0.39 %). We therefore believe that reducing the intensity of follow up of these patients should be considered.

Neo-adjuvant chemotherapy does not reduce surgical complexity nor the accuracy of intra-operative visual assessment of disease in advanced ovarian cancer

AIM

Compare the surgical complexity and histological accuracy of visual inspection of disease in patients undergoing primary debulking (PDS) versus delayed debulking surgery (DDS) following neo-adjuvant chemotherapy (NACT) for advanced ovarian cancer (AOC).

MATERIALS AND METHODS

All patients undergoing PDS or DDS for stage III / IV AOC at a UK cancer centre between January 2014-October 2021 were included. Retrospective data was collected accessing an electronic gynaecological oncology database, operation and histology records. Comparative frequencies of surgical procedures performed were calculated for primary versus delayed cohorts; and correlation between intra-operative suspicion of disease and specimen histology at PDS and DDS compared.

RESULTS

N=232. PDS was performed in 45.3% and DDS in 54.7% of patients; achieving complete cytoreduction in 77.2%. Appendicectomy, pelvic and para-aortic nodal dissection were undertaken significantly more often at primary surgery; whilst right diaphragm stripping, pelvic peritonectomy, splenectomy and cholecystectomy were more likely following NACT. We found no variation in bowel resection rates between cohorts. For the majority of specimens, there was no difference in correlation between intra-operative suspicion of disease and final histopathology - with a significantly lower positive predictive value for visual assessment demonstrated only for liver capsule and pelvic peritoneum at DDS.

CONCLUSION

NACT does not appear to reduce the complexity of surgery, including rates of bowel resection; nor accuracy of intra-operative visual assessment of disease. We therefore caution against both deferring to NACT to facilitate less radical delayed debulking; and any presumption that macroscopically abnormal tissue at DDS may represent inert post-NACT 'burn-out', mitigating indication for excision. We instead suggest reservation of the neo-adjuvant pathway for patients with poor PS and radiologically-confirmed surgical stopping points; and advocate equivalent and maximal cytoreductive effort to remove all visibly abnormal tissue in both the upfront and delayed surgical settings.

Evaluation of changes to work patterns in multidisciplinary cancer team meetings due to the COVID-19 pandemic: A national mixed-method survey study

BACKGROUND

It is not well understood the overall changes that multidisciplinary teams (MDTs) have had to make in response to the COVID-19 pandemic, nor the impact that such changes, in addition to the other challenges faced by MDTs, have had on decision-making, communication, or participation in the context of MDT meetings specifically.

METHODS

This was a mixed method, prospective cross-sectional survey study taking place in the United Kingdom between September 2020 and August 2021.

RESULTS

The participants were 423 MDT members. Qualitative findings revealed hybrid working and possibility of virtual attendance as the change introduced because of COVID-19 that MDTs would like to maintain. However, IT-related issues, slower meetings, longer lists and delays were identified as common with improving of the IT infrastructure necessary going forward. In contrast, virtual meetings and increased attendance/availability of clinicians were highlighted as the positive outcomes resulting from the change. Quantitative findings showed significant improvement from before COVID-19 for MDT meeting organisation and logistics (M = 45, SD = 20) compared to the access (M = 50, SD = 12, t(390) = 5.028, p = 0.001), case discussions (M = 50, SD = 14, t(373) = -5.104, p = 0.001), and patient representation (M = 50, SD = 12, t(382) = -4.537, p = 0.001) at MDT meetings.

DISCUSSION

Our study explored the perception of change since COVID-19 among cancer MDTs using mixed methods. While hybrid working was preferred, challenges exist. Significant improvements in the meeting organisation and logistics were reported. Although we found no significant perceived worsening across the four domains investigated, there was an indication in this direction for the case discussions warranting further 'live' assessments of MDT meetings.

Right ventricular and left ventricular diameters are independent predictors of death or cardiopulmonary resuscitation in intermediate and high-risk pulmonary embolisms

Background

Increased right ventricular (RV) dilation measured by the ratio of RV diameter (RVD) to left ventricular (LV) diameter (LVD) (RV:LV) is associated with pulmonary embolism (PE) severity and mortality. Data regarding the individual contributions of RVD and LVD are limited.

Purpose

To examine RVD and LVD as independent contributors to death or need for cardiopulmonary resuscitation (CPR) in intermediate- or high-risk PEs treated with surgical or catheter-based strategies

Methods

We measured basal RVD and LVD on presenting transthoracic echocardiograms (TTE) using the diastolic 4-chamber view on 127 PEs managed with surgical embolectomy (n=95, 75%), extracorporeal membrane oxygenation (n=23, 18%), or catheter-directed embolectomy (n=9, 7%) for intermediate- (64%) or high-risk (36%) PE (based on European Society of Cardiology criteria) between 2005 and 2022. The primary outcome was the composite of death (n=2) or survivors requiring CPR (n=10).

Results

A total of 127 patients were analyzed. Subjects were 57±14 years, 38% women, BMI 34±8. Mean RVD and LVD were 4.4±0.9 cm and 3.9±0.8 cm respectively. All presented with severe RV dysfunction on TTE and elevated cardiac biomarkers (Troponin-I or B-type natriuretic peptide). Mean RV:LV was 1.2±0.3 (range 0.7 to 2.8). Using logistic regression, higher RV:LV was associated with increased odds of death or CPR (odds ratio (OR) 15 [95% confidence interval (CI): 2.5, 82] per 1-unit increase, p=0.002. RV:LV >1.2 was the cutoff most associated with death or CPR, OR 7.2 [95% CI: 1.5, 34.5], p=0.01. Increasing RVD [OR 3.8 (95% CI: 1.1, 12.8), p=0.03] and decreasing LVD [OR 4.9 (95% CI: 1.3, 16.9), p=0.02] were independent predictors of death or CPR. RVD >5.0 cm (OR 5.9 [95% CI: 1,5, 23.2], p 0.01) and LVD <3.6 cm (OR 7.0 [95% CI: 1.7, 27.9], p=0.006) were the cutoff values most associated with the primary outcome. These cutoff values remained significant predictors even after adjustment for body surface area. Other parameters or RV size and function (diastolic area, systolic area and fractional area change) did not predict death or CPR. All of the subjects meeting the primary outcome had high-risk PE.

Discussion

In addition to RV:LV greater than 1.2, RVD and LVD were independently associated with death or CPR among high- or intermediate risk PEs. The independent contribution of declining LVD on PE mortality is a novel finding and highlights PE associatient LV pathophysiology (hyperdynamic and underfilled) antecedent to hemodynamic collapse. PE literature focuses on RV dilation as a predictor of PE mortality. LVD may represent a useful measure to risk stratify PE patients and predict hemodynamic decompensation.

Funding Acknowledgement

Type of funding sources: None.

Does the character of the hospital of primary management influence outcomes in patients treated for presumed early stage endometrial cancer and atypical endometrial hyperplasia: a comparison of outcomes from a cancer unit and cancer centre

A retrospective study from 2015 to 2020 comparing overall survival (OS) outcomes of a cancer unit and centre for presumed early stage endometrial cancers is presented. Cancer centres manage these presumed early endometrial cancer (EC) in situations of complex co-morbidities, surgical challenges as well as their own local unit patients. Our analysis compares 138 patients at KMH (unit) and 282 patients at RDH (centre) on OS, patient demographics, grading histology and final histology. Patients with presumed early stage EC can be reassured regarding no difference in OS between the cancer unit and centre management (p = .05). However, rates of minimal access surgery were higher at the cancer centre compared to the unit (93.2% versus 68.1%). The rates of upstaged disease were 4% and 8.8% at the cancer unit and centre respectively (p = .096). Sentinel node biopsy and genomic assessment may change future thresholds for centre-level management due to rates of upstaged disease.Impact StatementWhat is already known on this subject? Presumed lower risk endometrial cancers (endometrioid grades 1 and 2) have a rate of occult nodal involvement of only 1.4%. The BGCS does not recommend lymphadenectomy for low-risk endometrial cancers. These low-risk endometrial cancers should be managed with a hysterectomy and bilateral salpingo-ophrectomy via minimal access surgery. In view of the low rates of occult nodal involvement in low-risk endometrial cancer, surgery can be offered at a cancer unit.What do the results of this study add? Our study demonstrates there is no disadvantage in overall survival in the surgical management of presumed low-risk endometrial cancers at cancer units and centres. However, cancer centres have higher rates of minimal access to surgery despite managing a more elderly population. Our rates of upstaged disease of 4% and 8.8% at the cancer unit and centre indicate a potential benefit of pelvic lymph node assessment.What are the implications of these findings for clinical practice and/or further research? Sentinel lymph node biopsy does not have the surgical morbidity associated with systematic lymph node dissection. Therefore, when applied to presumed early stage endometrial cancer, there are potential changes in the threshold for centre-level management to improve overall survival.

Cancer multidisciplinary team meetings: impact of logistical challenges on communication and decision-making

Background

Multidisciplinary teams (MDTs) are widely used in cancer care. Recent research points to logistical challenges impeding MDT decision-making and dissatisfaction among members. This study sought to identify different types of logistical issues and how they impacted team processes.

Methods

This was a secondary analysis of a cross-sectional observational study. Three cancer MDTs (breast, colorectal, and gynaecological) were recruited from UK hospitals. Validated observational instruments were used to measure decision-making (Metrics of Observational Decision-making, MDT-MODe), communication (Bales' Interaction Process Analysis, Bales' IPA), and case complexity (Measure of Case Discussion Complexity, MeDiC), including logistical challenges (Measure of Case Discussion Complexity, MeDiC), across 822 case discussions from 30 videoed meetings. Descriptive analysis and paired samples t tests were used to identify and compare frequency of different types of logistical challenges, along with partial correlations, controlling for clinical complexity of cases, to understand how such issues related to the MDT decision-making and communication.

Results

A significantly higher frequency of administrative and process issues (affecting 30 per cent of cases) was seen compared with the frequency of equipment issues (affecting 5 per cent of cases; P < 0.001) and the frequency of the attendance issues (affecting 16 per cent of cases; P < 0.001). The frequency of the attendance issues was significantly higher than the frequency of equipment issues (P < 0.001). Partial correlation analysis revealed that administrative and process issues, including attendance, were negatively correlated with quality of information (r = −0.15, P < 0.001; r = −0.11, P < 0.001), and equipment issues with the quality of contribution to meeting discussion (r = −0.14, P < 0.001). More questioning and answering by MDT members was evident with the administrative and process issues (r = 0.21, P < 0.001; r = 0.19, P < 0.001). Some differences were observed in teams' socioemotional reactions to the administrative and process issues with the gynaecological MDT showing positive correlation with positive socioemotional reactions (r = 0.20, P < 0.001), and the breast cancer MDT with negative socioemotional reactions (r = 0.17, P < 0.001).

Conclusion

Administrative and process issues were the most frequent logistical challenges for the studied teams. Where diagnostic results were unavailable, and inadequate patient details provided, the quality of decision-making was reduced.

Lactate Is a Reliable Predictor of ICU Length of Stay Following Ultra-radical Ovarian Cancer Surgery

BACKGROUND/AIM

With a greater proportion of women with advanced ovarian cancer (AOC) successfully undergoing radical cytoreductive surgery, the demand on peri-operative resources - including intensive care (ICU) beds - is also on the rise. Extended post-operative ICU length of stay (LOS) confers increased patient morbidity and mortality. Several variables associated with prolonged ICU LOS following AOC surgery have been identified. We aimed to evaluate the predictive value of serum lactate levels.

PATIENTS AND METHODS

All patients undergoing ultra-radical surgery for AOC in a large cancer centre over a 34-month period between 2018-2021 were identified via the institution tumour registry. Data were collected retrospectively via electronic care and operating records; biochemistry, radiology, and histopathology databases.

RESULTS

In total, 63 patients were identified. Elevated intra-operative serum lactate levels were associated with significantly longer length of ICU post-operative stay. Longer time for hyperlactaemia to normalise following surgery also conferred significantly longer ICU, high dependency and total hospital LOS. Greater blood loss, higher surgical complexity and peritoneal carcinomatosis score, and longer operating time were associated with higher - and persistently elevated - peri-operative lactate levels.

CONCLUSION

Serum lactate in the context of ultra-radical surgery for AOC represents an accessible and inexpensive marker with potential to not only reliably predict LOS, but also to serve as a dynamic prompt for early targeted intervention. Early recognition and correction of hyperlactaemia following AOC may reduce ICU LOS limiting both the resource pressure and patient morbidity/mortality sequelae.

Poor anaerobic threshold and VO2 max recorded during cardiopulmonary exercise testing (CPET) prior to cytoreductive surgery in advanced (stage 3/4) ovarian cancer (AOC) is associated with suboptimal cytoreduction but does not preclude maximum effort cytoreduction

This study assessed Cardiopulmonary Exercise Testing (CPET) in predicting oncological outcomes, post-operative recovery and complications in advanced ovarian cancer (AOC) cytoreductive surgery. We reviewed all patients who had CPET prior to AOC cytoreductive surgery with evidence of upper abdominal disease on preoperative imaging at the University Hospitals of Derby and Burton (UHDB) between August 2016 and July 2019. Patients were stratified by AT and maximum VO₂ levels. 43 patients were identified. AT showed no relationship with major complications. 100% of patients in the AT ≥11 group received R0 (n = 21, 91.30%), or R1 (n = 2, 8.70%) cytoreduction, whereas in the AT <11 group, only 75.00% achieved and R0 or R1 resection (p = .02). Surgical complexity was higher in the AT ≥11 group (p = .001) and the VO₂ ≥15 group (p = .0006). No other correlations were seen between AT or VO₂ max and complications or readmissions. No difference in overall survival was seen if R0 resection was achieved.IMPACT STATEMENTWhat is already known on this subject? CPET testing allows pre-operative assessment of functional capacity to generate variables that can be used as a risk-stratification tool for major surgery. Whilst CPET testing has been shown to predict morbidity in non-gynaecological surgery, it remains unproven in cytoreductive surgery for ovarian cancer surgery despite being increasingly utilised.What do the results of study add? Our data suggest that CPET testing does not predict complication rates or survival in AOC. Patients with poor CPET performance are more likely to receive suboptimal cytoreductive outcomes from surgery.What are the implications of these findings for clinical practice and/or further research? CPET results should not be used to discount patients from cytoreductive surgery further research should address the interplay with nutrition, haematological markers, neoadjuvant chemotherapy and CPET performance.

Does the Performance of Splenectomy as Part of Cytoreductive Surgery Carry a Worse Prognosis Than in Patients Not Receiving Splenectomy? A Propensity Score Analysis and Review of the Literature

BACKGROUND & OBJECTIVES

Ultra-radical (UR) procedures, including splenectomy, are utilized to increase complete cytoreduction rates during Cytoreductive Surgery (CRS) performed with the aim of complete macroscopic clearance of disease. The purpose of this study was to investigate if splenectomy negatively impacts survival when undertaken during CRS for advanced ovarian cancer (AOC) and compare published splenectomy and cytoreduction rates.

METHODS

A retrospective review of all consecutive patients who underwent cytoreductive surgery for AOC between 16/05/2013-28/01/2019. Survival, baseline patient characteristics, complications and surgical parameters were recorded. Propensity scored matching (PSM) was performed to reduce bias.

RESULTS

154 patients identified over 71 months. 97 underwent standard, 57 underwent UR surgery, 27 patients received splenectomy (17.5%) No difference was seen in overall survival (OS) between all patients (median OS 34 months (95%CI 25.9-41.1) and patients who underwent splenectomy (median OS not yet reached) (p = >0.05). After PSM for various baseline covariates, no significant difference in splenectomy versus non-splenectomy patients (3-year survival 54% compared to 56%) (P > 0.05). Three splenectomy specific complications occurred; one each of pancreatic tail injury, left pleural effusion and streptococcal pharyngitis during chemotherapy. We found wide variation in utilization of splenectomy in published case series; from 9% to 35%.

CONCLUSIONS

Splenectomy performed as part of CRS is not detrimental to survival in AOC. There is a wide variation in utilization of splenectomy in published case series with little correlation with cytoreduction rates.

A multicentre cross-sectional observational study of cancer multidisciplinary teams: Analysis of team decision making

BACKGROUND

Multidisciplinary teams (MDT) formulate expert informed treatment recommendations for people with cancer. We set out to examine how the factors proposed by the functional perspective of group decision making (DM), that is, interaction process, internal factors (factors emanating from within the group such as group size), external circumstances (factors coming from the outside of the team), and case-complexity affect the quality of MDT decision making.

METHODS

This was a cross-sectional observational study. Three cancer MDTs were recruited with 44 members overall and 30 of their weekly meetings filmed. Validated observational instruments were used to measure quality of DM, interactions, and complexity of 822 case discussions.

RESULTS

The full regression model with the variables proposed by the functional perspective was significant, R2  = 0.52, F(20, 801) = 43.47, P < .001, adjusted R2  = 0.51. Positive predictors of DM quality were asking questions (P = .001), providing answers (P = .001), team size (P = .007), gender balance (P = .003), and clinical complexity (P = .001), while negative socioemotional reactions (P = .007), gender imbalance (P = .003), logistical issues (P = .001), time-workload pressures (P = .002), and time spent in the meeting (P = .001) were negative predictors. Second half of the meetings also saw significant decrease in the DM quality (P = .001), interactions (P = .001), group size (P = .003), and clinical complexity (P = .001), and an increase in negative socioemotional reactions (P = .001) and time-workload pressures (P = .001).

DISCUSSION

To the best of our knowledge, this is the first study to attempt to assess the factors proposed by the functional perspective in cancer MDTs. One novel finding is the effect of sociocognitive factors on team DM quality, while another is the cognitive-catch 22 effect: while the case discussions are significantly simpler in the second half of the meeting, there is significantly less time left to discuss the remaining cases, further adding to the cognitive taxation in teams who are now rapidly attempting to close their time-workload gap. Implications are discussed in relation to quality and safety.

Gaps and Overlaps in Cancer Multidisciplinary Team Communication: Analysis of Speech

Guided by the principles of conversation analysis, we examined the communication practices used to negotiate levels of participation in cancer multidisciplinary team meetings and their implications for patient safety. Three cancer teams participated. Thirty-six weekly meetings were video recorded, encompassing 822 case reviews. A cross-section was transcribed using Jefferson notation. We found a low frequency of gaps between speakers (3%), high frequency of overlaps (24%), and no-gaps-no-overlaps (73%), suggesting fast turn transitions. Securing a turn to speak is challenging due to a systematic reduction in turn-taking opportunities. We contribute to group research with the development of a microlevel methodology for studying multidisciplinary teams.

Primary and Interval Debulking Surgery Provide Similar Survival and Platinum Sensitivity Outcomes in Advanced Ovarian Cancer: A Retrospective Study

BACKGROUND/AIM

CHORUS and EORTC55971 trials demonstrated that neoadjuvant chemotherapy followed by interval debulking surgery (IDS) or primary debulking surgery (PDS) offered the same survival rates. These trials have since been criticised due to poor surgical complexity. We compared overall (OS), progression free (PFS), and platinum sensitivity in advanced ovarian cancer (AOC) patients undergoing IDS or PDS, who had received either intermediate or high complexity surgery to achieve complete cytoreduction.

PATIENTS AND METHODS

All patients with AOC treated between February 2014 and May 2019 obtaining complete cytoreduction with intermediate/high surgical complexity were included. Recurrence was defined according to GCIG criteria on radiological findings and/or CA125 levels.

RESULTS

Seventy-one patients (38 PDS and 33 IDS) with full recurrence data were identified. No statistical difference was seen between groups in OS, PFS or platinum sensitive interval.

CONCLUSION

PDS or IDS were both acceptable treatment options for AOC, showing similar survival and platinum sensitivity outcomes in patients undergoing intermediate or high complexity surgery.

Experiences of enhanced recovery after surgery in general gynaecology patients: An interpretative phenomenological analysis

There is little qualitative research exploring non-cancer gynaecology patients’ experiences of enhanced recovery after surgery (ERAS) protocols. Seven women participated in audio-recorded interviews, discussing their experiences of enhanced recovery after surgery for gynaecological surgery. Data were transcribed and analysed using interpretative phenomenological analysis. Three themes were identified: meeting informational needs, taking control of pain, and mobilising when feeling fragile. Control emerged as a key element throughout the themes and was supported by provision of factual information. While participants were generally satisfied with their experience, topics such as concerns about analgesic use, the informal role of staff in mobilisation, and the expressed desire for more experiential information for participants require further research.

Comparing the experience of enhanced recovery programme for gynaecological patients undergoing laparoscopic versus open gynaecological surgery: a prospective study

Background

Enhanced recovery has been shown to improve patients’ experience after surgery. There are no previous studies comparing patients’ experience between those undergoing laparoscopic and open gynaecological surgery. Therefore, the aim of this prospective study is to compare patients’ functional recovery based on milestones set by the enhanced recovery programme and patients’ satisfaction between the two groups.

Methods

All eligible patients undergoing gynaecological surgery within an enhanced recovery after surgery (ERAS) programme from March to August 2014 were involved in this study. All patients received the questionnaires on admission which were then collected prior to discharge. They were followed up by telephone within 7 days.

Results

Two hundred sixty-three patients were involved. One hundred forty-four questionnaires were returned (54% response rate). Fifty-one percent (n = 74) were from the laparoscopic group and 49% (n = 70) were from the laparotomy group. In terms of achieving milestones, more patients in the laparotomy group performed the deep breathing exercises (laparoscopic versus open; 66.2% versus 87.1% (p = 0.003). The laparoscopic group were more able to eat on day 0, but by day 1, there was no difference between the groups. Both groups were similar in their ability to drink (p = 0.98), mobilise (p = 0.123) and sit out in a chair (p = 0.511). In the laparoscopic group, the patients’ experience was better for pain control (p < 0.0001) and nausea control (p = 0.003) from recovery to day 1, and they were more able to put on their own clothes (p = 0.001) and were more confident in mobilising (p < 0.0001) and in going home (p < 0.0001). The laparoscopic group had greater patient satisfaction with their pain always being well controlled (p < 0.0001) whilst more patients in the laparotomy group reported being satisfied to very satisfied with their overall care on the gynaecology ward (p = 0.04). Both groups were equally satisfied with their care from nursing staff (p = 0.709) and doctors (p = 0.431).

Conclusion

The two groups were in general equally able to achieve the majority of the milestones despite differences in symptoms such as pain, nausea and confidence in mobilising and going home. Pre-operative education can empower patients to engage in their recovery. There is a high level of patient satisfaction in both groups.

"I'm 100% for it! I'm a convert!": women's experiences of a yoga programme during treatment for gynaecological cancer; an interpretative phenomenological analysis

OBJECTIVES

To explore patients' experiences of taking part in a yoga intervention while undergoing treatment for gynaecological cancer.

DESIGN

Sixteen women (age range 31-79 years; mean age 60) participated in focus groups based on a semi-structured question schedule. Resulting discussions were audio-recorded, transcribed verbatim and analysed using interpretative phenomenological analysis (IPA).

SETTING

Royal Derby Hospital, UK.

INTERVENTIONS

Patients took part in a 10-week course of Hatha yoga, where they participated in a one hour long class per week.

RESULTS

Three themes emerged from the data: applying breathing techniques, engaging in the physicality of yoga and finding a community. The first theme was particularly important to the patients as they noted the breadth and applicability of the techniques in their day-to-day lives. The latter two themes reflect physical and social perspectives, which are established topics in the cancer and yoga literature and are contextualised here within the women's experiences of cancer treatment.

CONCLUSIONS

The women's perceptions of the programme were generally positive, providing a previously unseen view of the patient experience of participating in a yoga intervention. The difference between the women's prior expectations and lived experiences is discussed.

Exploring the experience of an enhanced recovery programme for gynaecological cancer patients: a qualitative study

BACKGROUND

Perioperative enhanced recovery programmes (ERPs), identified as initiatives that improve care and save money, have been adopted by NHS Improvement and are currently being rolled out across many surgical departments within the NHS. To date, five papers have specifically explored patients' experiences of ERPs; none, however, has explored the gynaecological cancer patient experience.

METHODS

In total, 14 women (mean age, 66 years) participated in an audio-recorded face-to-face or telephone interview in which they discussed their experience of taking part in an ERP. The resulting data were transcribed verbatim and analysed using interpretative phenomenological analysis.

RESULTS

Two main themes emerged from the analysis. The first, 'Taking part in the programme', highlights two important aspects of the ERP: being given an opportunity to receive information and, following this, to build knowledge about the programme. The theme also explores the challenges associated with the programme, particularly around getting mobile and complying with its demands - the women report experiencing a constant battle between intuition and instruction. The second theme, 'Home', focuses on the role home plays in motivating the patients to aim for an early discharge from hospital. Patients describe their need to return to a suitable home and the need for support from others. They also discuss the importance of the follow-up phone call.

CONCLUSION

Overall, the patients in this study positively assessed the individual aspects of the ERP, in particular, information resources, the availability of the physiotherapist and the delivery of follow-up phone calls. These findings highlight the importance of developing and maintaining individual aspects of ERPs over time, to ensure their sensitivity and responsiveness to patient needs.

Expression and prognostic significance of the oncogenic K2P potassium channel KCNK9 (TASK-3) in ovarian carcinoma

BACKGROUND/AIMS

The TWIK-related acid sensitive K(+) channel-3 (TASK-3) is an oncogenic potassium channel. We investigated the expression of TASK-3 in human ovaries, examined its prognostic significance, and determined effects of TASK-3 blockers on cell proliferation and apoptosis.

MATERIALS AND METHODS

Immunofluorescence and western blotting were used to investigate TASK-3 expression in two ovarian cancer cell lines, normal ovarian surface epithelium and cancer. Immunohistochemistry quantified expression in an ovarian cancer tissue microarray. The effect of TASK-3 blocking agents on cell proliferation was investigated with the CellTiter 96® Aqueous Non-Radioactive Cell Proliferation assay and on apoptosis with flow cytometry.

RESULTS

TASK-3 expression was confirmed by immunofluorescence in the SKOV-3 and OVCAR-3 cell lines, normal ovaries (n=4) and ovarian tumours (n=4) and by western blotting in normal ovaries (n=6) and ovarian tumours (n=22). Immunohistochemistry demonstrated immunostaining in 99% of tumours (n=230). Increased immunostaining conferred a survival advantage (p=0.002; median survival of >24 months). TASK-3 blockers caused a significant reduction in cell proliferation and an increase in apoptosis in the SKOV-3 and OVCAR-3 cell lines.

CONCLUSION

TASK-3 is expressed in epithelial ovarian cancer, conferring a significant survival advantage on patients with increased expression. TASK-3-modulating agents have a significant effect on cell proliferation and apoptosis. Based on these results, we propose that TASK-3 could prove to be both a novel tumour marker and a new therapeutic target in ovarian cancer, but further investigation is required.

Thermoelectric properties of Bi-added Co4Sb12 skutterudites

Void filling in (I) Bi(x)-added Co(4)Sb(12) or (II) Sb/Bi substitution of Co(4)Sb(12-x)Bi(x) has been investigated for structural and thermoelectric properties evaluation. X-ray powder data Rietveld refinements combined with electron probe microanalyses showed a polycrystalline and practically Bi-free CoSb(3) skutterudite phase as the major constituent as well as a secondary Bi phase in the grain boundaries. For series I alloys, the electrical conductivity, Seebeck coefficient and thermal conductivity were measured as a function of temperature in the range from 450 to 750 K. The electrical conductivity of all the samples increased with increasing temperature, showing a semiconducting nature with smaller values of the Seebeck coefficient for higher Bi fractions. Conduction over the entire temperature range was found to arise from a single p-type carrier. Thermal conductivity showed a reduction with Bi added in all the samples, except for Bi(0.75)Co(4)Sb(12), and the lowest lattice thermal conductivity was found for a Bi-added fraction of 0.5. The maximum zT value of 0.53 at 632 K is higher than that of Co(4)Sb(12).

Preoperative platelet lymphocyte ratio as an independent prognostic marker in ovarian cancer

INTRODUCTION

Ovarian cancer is associated with high mortality due to presentation at advanced stage and high recurrence following treatment with chemotherapy. Most of the prognostic variables in ovarian cancer, including stage and residual disease, are amenable for assessment only after surgery. Currently there are no established preoperative markers including, CA-125, that can predict overall survival in patients with ovarian cancer. The aim of our study was to evaluate the prognostic significance of the preoperative haematological markers platelet lymphocyte ratio (PLR) and neutrophil lymphocyte ratio (NLR) in patients with ovarian cancer.

METHOD

Preoperative PLR and NLR were evaluated in 235 patients undergoing surgery for ovarian cancer. The prognostic significance of both markers was then determined by both uni- and multivariate analytical methods.

RESULTS

High preoperative PLR (p < 0.001) and NLR (p = 0.001) were significantly associated with poor survival using univariate Cox survival analysis. The median overall survival in patients with a PLR of < 300 was 37.4 months (95% CI 26.1-48.7) and 14.5 months (95% CI 11.7-17.2) in those with a PLR of > 300. PLR (p = 0.03) but not NLR (p = 0.575) retained its significance as a prognostic marker on multivariate Cox's regression analysis, along with stage (p < 0.001) and residual disease (p = 0.015).

CONCLUSION

We have shown for the first time that PLR is a novel independent prognostic marker in patients with ovarian cancer.

Synovial sarcoma of the vulva: a case report

Introduction

Contrary to its name, synovial sarcoma does not arise from the synovial membrane but from multipotent stem cells and can present in any part of the body. Very few cases of vulval synovial sarcoma have been reported in the literature; we report on such a presentation. These tumors can present as painless lumps, which must be completely excised to give the best prognosis. Therefore the diagnosis of synovial sarcoma should always be kept in mind in the management of vulval masses, especially in young patients.

Case presentation

We report the case of a 28-year-old Caucasian woman with synovial sarcoma of the vulva. Complete excision was possible in this case.

Conclusion

We have presented a rare case of synovial sarcoma of the vulva, which can be easily confused with lipoma of the vulva. The management of this tumor requires referral to a cancer centre, with a multidisciplinary approach.

The role of Eag and HERG channels in cell proliferation and apoptotic cell death in SK-OV-3 ovarian cancer cell line

BACKGROUND

The voltage gated potassium (K+) channels Eag and HERG have been implicated in the pathogenesis of various cancers, through association with cell cycle changes and programmed cell death. The role of these channels in the onset and progression of ovarian cancer is unknown. An understanding of mechanism by which Eag and HERG channels affect cell proliferation in ovarian cancer cells is required and therefore we investigated their role in cell proliferation and their effect on the cell cycle and apoptosis of ovarian cancer cells.

METHODS

The presence of Eag and HERG was determined in SK-OV-3 cells using immunofluorescence and western blotting. The effect of the Eag blockers (imipramine and clofilium) and HERG blockers (E-4031 and ergtoxin) on cell proliferation was assessed using the MTS assay with further investigation of their role in the cell cycle and apoptosis determined by flow cytometry.

RESULTS

Eag and HERG channels were present in the cytoplasm and nuclei of SK-OV-3 cells. There was significant inhibition of proliferation of SK-OV-3 cells by imipramine (P < 0.001) and ergtoxin (P < 0.05) at 72 hours of culture. Incubation of cells with ergtoxin led to the accumulation of cells in the S and G2/M phase, while cells accumulated in S phase after incubation with E-4031, with no effect on apoptosis. Imipramine did not affect the cell cycle but increased the proportion of SK-OV-3 cells undergoing early apoptosis.

CONCLUSION

Both Eag and HERG channels are expressed in SK-OV-3 ovarian cancer cells and have a role in cell proliferation. HERG channels affect the cell cycle while Eag channels are implicated in the inhibition of apoptosis of ovarian cancer cells. The family of Eag channels may represent a new therapeutic target for the treatment of ovarian cancer.

Eag and HERG potassium channels as novel therapeutic targets in cancer

Voltage gated potassium channels have been extensively studied in relation to cancer. In this review, we will focus on the role of two potassium channels, Ether à-go-go (Eag), Human ether à-go-go related gene (HERG), in cancer and their potential therapeutic utility in the treatment of cancer. Eag and HERG are expressed in cancers of various organs and have been implicated in cell cycle progression and proliferation of cancer cells. Inhibition of these channels has been shown to reduce proliferation both in vitro and vivo studies identifying potassium channel modulators as putative inhibitors of tumour progression. Eag channels in view of their restricted expression in normal tissue may emerge as novel tumour biomarkers.

The Eag potassium channel as a new prognostic marker in ovarian cancer

Background

Ovarian cancer is the second most common cancer of the female genital tract in the United Kingdom (UK), accounting for 6% of female deaths due to cancer. This cancer is associated with poor survival and there is a need for new treatments in addition to existing chemotherapy to improve survival. Potassium (K⁺) channels have been shown to be overexpressed in various cancers where they appear to play a role in cell proliferation and progression.

Objectives

To determine the expression of the potassium channels Eag and HERG in ovarian cancer tissue and to assess their role in cell proliferation.

Methods

The expression of Eag and HERG potassium channels was examined in an ovarian cancer tissue microarray. Their role in cell proliferation was investigated by blocking voltage-gated potassium channels in an ovarian cancer cell line (SK-OV-3).

Results

We show for the first time that high expression of Eag channels in ovarian cancer patients is significantly associated with poor survival (P = 0.016) unlike HERG channel expression where there was no correlation with survival. There was also a significant association of Eag staining with high tumour grade (P = 0.014) and presence of residual disease (P = 0.011). Proliferation of SK-OV-3 cells was significantly (P < 0.001) inhibited after treatment with voltage gated K⁺ channel blockers.

Conclusion

This novel finding demonstrates a role for Eag as a prognostic marker for survival in patients with ovarian cancer.

Pre-treatment white blood cell subtypes as prognostic indicators in ovarian cancer

OBJECTIVE

Inflammatory cells can both suppress and stimulate tumour growth and their influence on clinical outcome in cancer patients has been studied in various cancer types. Here we have investigated their influence on outcome in primary epithelial ovarian cancer.

STUDY DESIGN

Serum white blood cell numbers according to subtype were recorded prior to treatment in 136 patients with primary epithelial ovarian cancer. Their correlation with overall survival and disease-free survival was analysed using both univariate and multivariate analysis adjusting for the known prognostic factors (age, stage and debulking status).

RESULTS

Multivariate analysis demonstrated that a lower lymphocyte fraction of total white blood cells was significantly associated with mortality (p<0.01). On univariate analysis (p=0.0027, HR=1.15), and multivariate analysis of those patients who were optimally debulked (p=0.036, HR=1.17), a higher monocyte count was significantly associated with recurrence. On multivariate analysis amongst those who were suboptimally debulked, a higher eosinophil count was predictive of both recurrence (p=0.0037, HR=1.77) and mortality (p=0.033, HR=1.73).

CONCLUSION

High monocyte counts amongst those who were optimally debulked independently predict adverse outcome in primary epithelial ovarian cancer.

A distinct molecular profile associated with mucinous epithelial ovarian cancer

Mucinous epithelial ovarian cancers (MOC) are clinically and morphologically distinct from the other histological subtypes of ovarian cancer. To determine the genetic basis of MOC and to identify potential tumour markers, gene expression profiling of 49 primary ovarian cancers of different histological subtypes was performed using a customised oligonucleotide microarray containing >59 000 probesets. The results show that MOC express a genetic profile that both differs and overlaps with other subtypes of epithelial ovarian cancer. Concordant with its histological phenotype, MOC express genes characteristic of mucinous carcinomas of varying epithelial origin, including intestinal carcinomas. Differences in gene expression between MOC and other histological subtypes of ovarian cancer were confirmed by RT–PCR and/or immunohistochemistry. In particular, galectin 4 (LGALS4) was highly and specifically expressed in MOC, but expressed at lower levels in benign mucinous cysts and borderline (atypical proliferative) tumours, supporting a malignant progression model of MOC. Hence LGALS4 may have application as an early and differential diagnostic marker of MOC.

Cyclin D1, p53, and p21Waf1/Cip1 expression is predictive of poor clinical outcome in serous epithelial ovarian cancer

PURPOSE

Dysregulation of cell cycle control, in particular G(1)-S-phase transition, is implicated in the pathogenesis of most human cancers, including epithelial ovarian cancer (EOC). However, the prognostic significance of aberrant cell cycle gene expression in EOC remains unclear.

EXPERIMENTAL DESIGN

The expression of selected genes from the pRb pathway that regulates G(1)-S-phase progression, including cyclin D1, p16(Ink4a), cyclin E, p27(Kip1), p21(Waf1/Cip1), and p53, was examined in a consecutive series of 134 serous EOC using immunohistochemistry and the results correlated to disease outcome.

RESULTS

Molecular markers predictive of reduced overall survival in univariate analysis were overexpression of cyclin D1 (P = 0.03) and p53 (P = 0.03) and reduced expression of p27(Kip1) (P = 0.05) and p21(Waf1/Cip1) (P = 0.02), with the latter three also being prognostic for a shorter progression-free interval. In addition, patients displaying overexpression of p53 with concurrent loss of p21(Waf1/Cip1) had a significantly shorter overall (P = 0.0008) and progression-free survival (P = 0.0001). On multivariate analysis, overexpression of cyclin D1 and combined loss of p21(Waf1/Cip1) in the presence of p53 overexpression were independent predictors of overall survival. Similarly, the combination of p21(Waf1/Cip1) loss and p53 overexpression was independently predictive of a shorter progression-free interval. Overexpression of p53 and cyclin E and reduced expression of p27(Kip1) and p21(Waf1/Cip1) were significantly associated with increasing tumor grade.

CONCLUSIONS

This study confirms that dysregulation of cell cycle genes is common in EOC, and that aberrant expression of critical cell cycle regulatory proteins can predict patient outcome in serous EOC.

Central pelvic recurrence 7 years after radical vaginal trachelectomy

BACKGROUND

We report a case of central pelvic recurrence 7 years after radical vaginal trachelectomy for adenocarcinoma of the cervix.

CASE

A 30-year-old woman was treated by radical vaginal trachelectomy and bilateral pelvic lymph node dissection (a fertility sparing procedure) in 1996 for cervical cancer. Pathology demonstrated a well differentiated, stage 1B1 adenocarcinoma. She presented 7 years later with a central pelvic recurrence measuring 30 mm in width. She subsequently underwent radical hysterectomy for central clearance and did not require post-operative radiotherapy.

CONCLUSIONS

Should selected patients who were initially treated by radical trachelectomy for early stage cervical cancer, in particular those with adenocarcinoma (as 50% of recurrences have been reported in this group of patients), be offered hysterectomy once child bearing is complete?

Overexpression of the cell adhesion molecules DDR1, Claudin 3, and Ep-CAM in metaplastic ovarian epithelium and ovarian cancer

PURPOSE

A better understanding of the molecular pathways underlying the development of epithelial ovarian cancer (EOC) is critical to identify ovarian tumor markers for use in diagnostic or therapeutic applications. The aims of this study were to integrate the results from 14 transcript profiling studies of EOC to identify novel biomarkers and to examine their expression in early and late stages of the disease.

EXPERIMENTAL DESIGN

A database incorporating genes identified as being highly up-regulated in each study was constructed. Candidate tumor markers were selected from genes that overlapped between studies and by evidence of surface membrane or secreted expression. The expression patterns of three integral membrane proteins, discoidin domain receptor 1 (DDR1), claudin 3 (CLDN3), and epithelial cell adhesion molecule, all of which are involved in cell adhesion, were evaluated in a cohort of 158 primary EOC using immunohistochemistry.

RESULTS

We confirmed that these genes are highly overexpressed in all histological subtypes of EOC compared with normal ovarian surface epithelium, identifying DDR1 and CLDN3 as new biomarkers of EOC. Furthermore, we determined that these genes are also expressed in ovarian epithelial inclusion cysts, a site of metaplastic changes within the normal ovary, in borderline tumors and in low-grade and stage cancer. A trend toward an association between low CLDN3 expression and poor patient outcome was also observed.

CONCLUSIONS

These results suggest that up-regulation of DDR1, CLDN3, and epithelial cell adhesion molecule are early events in the development of EOC and have potential application in the early detection of disease.

The effect of the preemptive use of the NMDA receptor antagonist dextromethorphan on postoperative analgesic requirements

Both central sensitization after peripheral tissue injury and the development of opiate tolerance involve activation of N-methyl-D-aspartate receptors. In this double-blinded, randomized study, we investigated the preemptive versus postincisional effects of dextromethorphan, an N-methyl-D-aspartate receptor antagonist, on postoperative pain management. Sixty ASA I and II patients undergoing elective upper abdominal surgery were randomly allocated to three equally sized groups. The Preincisional group patients received dextromethorphan (120 mg) IM 30 min before skin incision and a placebo (isotonic saline) 30 min before the end of surgery. The Postincisional group received the same dose of dextromethorphan 30 min before the end of surgery and a placebo 30 min before skin incision, and the Control group received a placebo both 30 min before skin incision and 30 min before the end of surgery. A standard general anesthetic technique including fentanyl, propofol, isoflurane, and atracurium was used. Postoperative meperidine patient-controlled analgesia (PCA) was used. There were no significant group differences in the median pain scores except in the visual analog scale at 6 h both at rest and on movement; these were significantly lower in the Preincisional group than the other two groups (P < 0.05). The mean time to initiation of PCA was significantly longer in the Preincisional than in the Postincisional and Control groups (mean [SD]: 10.7 [2.2 h], 5.4 [2.1 h], and 3.7 [1.6 h], respectively; P < 0.001]. The 24-h PCA-meperidine consumption was significantly less in the Preincisional than in the Postincisional and Control groups (mean [SD]: 140 [60 mg], 390 [80 mg], and 570 [70 mg], respectively; P < 0.001]. The incidence of postoperative hypoxemia (SpO(2) < 90%) and nausea was significantly less in the Preincisional group (P < 0.05). In conclusion, preincisional IM 120 mg dextromethorphan compared with the same postincisional dose significantly reduced postoperative meperidine consumption.

IMPLICATIONS

IM administration of preincisional dextromethorphan (120 mg), allowing the use of a larger dose sufficient to block the central sensitization caused by activation of the N-methyl-D-aspartate receptors, provides preemptive analgesia and has a supportive role in postoperative pain relief, as shown by a significant decrease in 24-h meperidine consumption.

Blood meal identification by using Microdot ELISA in vector mosquitoes

The blood meals of five mosquito species which are vectors for malaria, J.E. and Filaria were determined by using Microdot ELISA technique, which is a rapid and sensitive method. A total of 4354 freshly fed mosquitoes comprising of Anopheles culicifacies, An stephensi, Culex quinquefasciatus, Cx. vishnui gp. and Cx. tritaeniorhynchus were tested. Results of the study reveal that highest proportion of An. culicifacies between 76-100% fed on bovine host followed by 0.3 to 24.2% on human. Cx. vishnui showed 1.9% feeding on human, 49-87.7% on bovine and 7.4-12.3% on the pigs. It has been observed that malaria vectors namely An. culicifacies and An. stephensi are still zoophilic in nature. Similarly, the vector of J.E. namely Culex vishnui gp. and Cx. tritaeniorhynchus also fed on cattle but some samples have indicated feeding of blood meal from pigs.

Molecular and immunological analysis of an ABC transporter complex required for cytochrome c biogenesis

The helABC genes are predicted to encode an ATP-binding cassette (ABC) transporter necessary for heme export for ligation in bacterial cytochrome c biogenesis. The recent discoveries of homologs of the helB and helC genes in plant mitochondrial genomes suggest this is a highly conserved transporter in prokaryotes and some eukaryotes with the HelB and HelC proteins comprising the transmembrane components. Molecular genetic analysis in the Gram-negative bacterium Rhodobacter capsulatus was used to show that the helABC and helDX genes are part of an operon linked to the secDF genes. To facilitate analysis of this transporter, strains with non-polar deletions in each gene, epitope and reporter-tagged HelABCD proteins, and antisera specific to the HelA and HelX proteins were generated. We directly demonstrate that this transporter is present in the cytoplasmic membrane as an HelABCD complex. The HelB and HelC but not HelD proteins are necessary for the binding and stability of the HelA protein, the cytoplasmic subunit containing the ATP-binding region. In addition we show that the HelA protein co-immunoprecipitates with either the HelC or HelD proteins. Thus, the HelABCD heme export complex is distinguished by the presence of four membrane-associated subunits and represents a unique subfamily of ABC transporters.

Excretion of ammonium by a nifL mutant of Azotobacter vinelandii fixing nitrogen

A mutation in the gene upstream of nifA in Azotobacter vinelandii was introduced into the chromosome to replace the corresponding wild-type region. The resulting mutant, MV376, produced nitrogenase constitutively in the presence of 15 mM ammonium. When introduced into a nifH-lacZ fusion strain, the mutation permitted beta-galactosidase production in the presence of ammonium. The gene upstream of nifA is therefore designated nifL because of its similarity to the Klebsiella pneumoniae nifL gene in proximity to nifA, in mutant phenotype, and in amino acid sequence of the gene product. The A. vinelandii nifL mutant MV376 excreted significant quantities of ammonium (approximately 10 mM) during diazotrophic growth. In contrast, ammonium excretion during diazotrophy was much lower in a K. pneumoniae nifL deletion mutant (maximum, 0.15 mM) but significantly higher than in NifL+ K. pneumoniae. The expression of the A. vinelandii nifA gene, unlike that of K. pneumoniae, was not repressed by ammonium.

The product of the nitrogen fixation regulatory gene nfrX of Azotobacter vinelandii is functionally and structurally homologous to the uridylyltransferase encoded by glnD in enteric bacteria

We sequenced the nitrogen fixation regulatory gene nfrX from Azotobacter vinelandii, mutations in which cause a Nif- phenotype, and found that it encodes a 105-kDa protein (NfrX), the N terminus of which is highly homologous to that of the uridylyltransferase-uridylyl-removing enzyme encoded by glnD in Escherichia coli. In vivo complementation experiments demonstrate that the glnD and nfrX products are functionally interchangeable. A vinelandii nfrX thus appears to encode a uridylyltransferase-uridylyl-removing enzyme, and in this paper we report the first sequence of such a protein. The Nif- phenotype of nfrX mutants can be suppressed by a second mutation in a recently identified nifL-like gene immediately upstream of nifA in A. vinelandii. NifL mediates nif regulation in response to the N status in A. vinelandii, presumably by inhibiting NifA activator function as occurs in Klebsiella pneumoniae; thus, one role of NfrX is to modify, either directly or indirectly, the activity of the nifL product.

Effect of phospholipid structure on stability and survival times of liposomes in circulation

The phosphatidylcholine (PC) component of liposomes was structurally modified by replacing its C-1, or both C-1 and C-2, ester linkage(s) with an ether and/or carbamyl bond(s) or by changing its steric configuration. Small unilamellar liposomes were formed from PC, traces of the corresponding 14C-labeled PC and cholesterol in the presence of 6-carboxyfluorescein (02.M) by sonication, and purified by centrifugation. These liposomes were administered intravenously to rats, and their stability in blood as well as the rate of their clearance from the circulation were determined. Stability and survival times of liposomes were markedly increased by modifying both the C-1 and the C-2 ester linkages in PC. A similar but quantitatively smaller effect was observed when only the C-1 ester linkage was modified. However, the stability remained unaffected by changing the steric configuration of PC, but this modification influenced the clearance rate of liposomes from the circulation. These results demonstrate that both stability in blood and the clearance rate from circulation can be modulated by structurally modifying the ester linkages in the phospholipid component of liposomes.

Protection of mice against Plasmodium berghei infection by a tuftsin derivative

In Plasmodium berghei infections, the mortality rate and parasitaemias were significantly reduced and the mean survival time was considerably enhanced by pretreating the animals with a tuftsin derivative, Thr-Lys-Pro-ARg-NH-(CH2)2-NHCOC15H31. This effect of the modified tuftsin was further increased upon its incorporation in the liposome bilayer. These results indicate that tuftsin and its derivatives may prove useful in enhancing nonspecific host resistance against protozoan infections.

Influence of the phospholipid structure on the stability of liposomes in serum

The effect of serum on the structural integrity of liposomes consisting of ether and/or carbamyl analogs of 1,2-diester phosphatidylcholine (PC) has been evaluated by measuring both the efflux of the entrapped 6-carboxyfluorescein and the lipid transfer to serum proteins, and the results have been compared with the egg PC liposomes. Replacement of the C-1 ester bond in PC by an ether linkage did not significantly enhance the liposome stability, but it was markedly increased upon introducing further structural changes in the C-2 ester region of the resulting 1-ether-2-ester PC. However, the stability was not influenced by altering the steric configuration of the latter phospholipid. These results strongly suggest that lysis of liposomes in serum can be prevented by structurally modifying the ester bond(s) in the phospholipid component of liposomes.

Antibody-mediated targeting of liposomes to erythrocytes in whole blood

F(ab')2 fragments derived from anti-rat erythrocyte antibody or normal rabbit serum IgG were covalently attached to the surface of liposomes consisting of equimolar amounts of egg phosphatidylcholine and cholesterol. These liposomes were interacted with rat, monkey or mouse blood, and their binding to both red and white blood cells was determined. Results of these studies show that coupling of liposomes to anti-rat erythrocyte F(ab')2 considerably enhances their binding to erythrocytes in rat blood. However, no such increase in the binding was observed with rat leukocytes or monkey and mouse erythrocytes. Besides, the interactions between the liposomes and target cells did not affect the permeability properties of the liposome bilayer. These observations indicate that liposomes coupled to cell-specific antibodies may serve as highly useful carriers for homing of drugs/enzymes to specific cells in biophase.

Phase behavior of carbamyloxyphosphatidylcholine, a sphingolipid analogue

The phase behavior of two series of phosphatidylcholines (PC) possessing carbamyloxy-linked fatty acids has been studied by differential scanning calorimetry. These non-natural phosphatidylcholines are of interest because they possess the capability of forming interlipid hydrogen bonds via the carbamyloxy function and as such can serve as a model for sphingolipids, the phase behavior of which is thought to be dominated by interlipid hydrogen bonding. Furthermore, carbamyloxyphosphatidylcholines form unusually stable liposomes, and thus have potential in drug delivery. Carbamyloxyphosphatidylcholines of the type di-(CnH2n+1NHCOO)-PC, where n = 13, 15, or 17, exhibit metastable polymorphism. Cooling from the liquid crystalline state results in formation of a metastable low-temperature polymorph I, which must transform into a stable low-temperature polymorph II before the liquid crystalline state can be reached again. Carbamyloxyphosphatidylcholines of the type 1-C16:0-2-(CnH2n+1NHCOO)-PC exhibit similar metastable polymorphism. This metastability is similar to that exhibited by certain cerebrosides and sphingomyelins and indicates that the sphingosine backbone is not a prerequisite for this type of metastability. Furthermore, the carbamyloxy group is reversed in orientation compared with the amide of sphingolipids (-NHCO- versus -CONH-), suggesting that the intermolecular hydrogen bonding potential, rather than some highly specific steric or conformational constraint, is responsible for the observed metastability of sphingolipids.