The empty pelvis syndrome: a core data set from the PelvEx collaborative

BACKGROUND

Empty pelvis syndrome (EPS) is a significant source of morbidity following pelvic exenteration (PE), but is undefined. EPS outcome reporting and descriptors of radicality of PE are inconsistent; therefore, the best approaches for prevention are unknown. To facilitate future research into EPS, the aim of this study is to define a measurable core outcome set, core descriptor set and written definition for EPS. Consensus on strategies to mitigate EPS was also explored.

METHOD

Three-stage consensus methodology was used: longlisting with systematic review, healthcare professional event, patient engagement, and Delphi-piloting; shortlisting with two rounds of modified Delphi; and a confirmatory stage using a modified nominal group technique. This included a selection of measurement instruments, and iterative generation of a written EPS definition.

RESULTS

One hundred and three and 119 participants took part in the modified Delphi and consensus meetings, respectively. This encompassed international patient and healthcare professional representation with multidisciplinary input. Seventy statements were longlisted, seven core outcomes (bowel obstruction, enteroperineal fistula, chronic perineal sinus, infected pelvic collection, bowel obstruction, morbidity from reconstruction, re-intervention, and quality of life), and four core descriptors (magnitude of surgery, radiotherapy-induced damage, methods of reconstruction, and changes in volume of pelvic dead space) reached consensus-where applicable, measurement of these outcomes and descriptors was defined. A written definition for EPS was agreed.

CONCLUSIONS

EPS is an area of unmet research and clinical need. This study provides an agreed definition and core data set for EPS to facilitate further research.

Evaluation of prognostic risk models for postoperative pulmonary complications in adult patients undergoing major abdominal surgery: a systematic review and international external validation cohort study

BACKGROUND

Stratifying risk of postoperative pulmonary complications after major abdominal surgery allows clinicians to modify risk through targeted interventions and enhanced monitoring. In this study, we aimed to identify and validate prognostic models against a new consensus definition of postoperative pulmonary complications.

METHODS

We did a systematic review and international external validation cohort study. The systematic review was done in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. We searched MEDLINE and Embase on March 1, 2020, for articles published in English that reported on risk prediction models for postoperative pulmonary complications following abdominal surgery. External validation of existing models was done within a prospective international cohort study of adult patients (≥18 years) undergoing major abdominal surgery. Data were collected between Jan 1, 2019, and April 30, 2019, in the UK, Ireland, and Australia. Discriminative ability and prognostic accuracy summary statistics were compared between models for the 30-day postoperative pulmonary complication rate as defined by the Standardised Endpoints in Perioperative Medicine Core Outcome Measures in Perioperative and Anaesthetic Care (StEP-COMPAC). Model performance was compared using the area under the receiver operating characteristic curve (AUROCC).

FINDINGS

In total, we identified 2903 records from our literature search; of which, 2514 (86·6%) unique records were screened, 121 (4·8%) of 2514 full texts were assessed for eligibility, and 29 unique prognostic models were identified. Nine (31·0%) of 29 models had score development reported only, 19 (65·5%) had undergone internal validation, and only four (13·8%) had been externally validated. Data to validate six eligible models were collected in the international external validation cohort study. Data from 11 591 patients were available, with an overall postoperative pulmonary complication rate of 7·8% (n=903). None of the six models showed good discrimination (defined as AUROCC ≥0·70) for identifying postoperative pulmonary complications, with the Assess Respiratory Risk in Surgical Patients in Catalonia score showing the best discrimination (AUROCC 0·700 [95% CI 0·683-0·717]).

INTERPRETATION

In the pre-COVID-19 pandemic data, variability in the risk of pulmonary complications (StEP-COMPAC definition) following major abdominal surgery was poorly described by existing prognostication tools. To improve surgical safety during the COVID-19 pandemic recovery and beyond, novel risk stratification tools are required.

FUNDING

British Journal of Surgery Society.

1046 STANDARDIZING THE APPROACH TO POSTURAL HYPOTENSION: A QUALITY IMPROVEMENT PROJECT

Background & Aims

Falls in the older population cause significant morbidity and mortality, and can be a catalyst for deconditioning and a decrease in functional baseline. In the long-term, this results in higher levels of care needs and health issues. As orthostatic hypotension is a common cause for falls in the elderly, our QIP aims to develop a standardized approach to postural hypotension assessment.

Methodology

We undertook two rounds of retrospective data collection on the ward focusing on LSBP as part of the assessment that should be completed on every patient who presents with a fall. In between we undertook an intense period of small group education sessions. We involved a nurse and an HCA in delivering this teaching to ensure sustained change. We also created cards demonstrating the correct technique of doing a LSBP and attached these to all BP machines. Finally, we introduced a midday board round which allowed for more effective communication between the MDT.

Results

In cycle 1, 26% of patients presenting with a fall had a LSBP done prior to discharge whilst in cycle 2, 56% of patients did. We significantly improved the technique and documentation on our electronic system from 0% in the first cycle to 95% in the second. However, this increase in LSBP comes from increased nursing staff completion and documentation as opposed to more doctors requesting a LSBP as part of the falls assessment, with only 63% of patients having documented requests in both cycles.

Conclusion

Our results were encouraging but also highlighted further areas for development in this area. Moving forward, we have extended the project to increase doctors’ awareness of the falls assessment. We have presented at the departmental meeting and included multifactorial falls assessment teaching in the induction handbook to allow for sustained change.

Experimental pain phenotyping in community-dwelling individuals with knee osteoarthritis

Pain among individuals with knee osteoarthritis (OA) is associated with significant disability in older adults, and recent evidence demonstrates enhanced experimental pain sensitivity. Although previous research showed considerable heterogeneity in the OA clinical pain presentation, less is known regarding the variability in responses to experimental pain. The present study included individuals with knee OA (n = 292) who participated in the Understanding Pain and Limitations in Osteoarthritic Disease study and completed demographic and psychological questionnaires followed by a multimodal quantitative sensory testing (QST) session. Quantitative sensory testing measures were subjected to variable reduction procedures to derive pain sensitivity index scores, which in turn were entered into a cluster analysis. Five clusters were significantly different across all pain sensitivity index variables (P < 0.001) and were characterized by: (1) low pain sensitivity to pressure pain (N = 39); (2) average pain sensitivity across most modalities (N = 88); (3) high temporal summation of punctate pain (N = 38); (4) high cold pain sensitivity (N = 80); and (5) high sensitivity to heat pain and temporal summation of heat pain (N = 41). Clusters differed significantly by race, gender, somatic reactivity, and catastrophizing (P < 0.05). Our findings support the notion that there are distinct subgroups or phenotypes based on experimental pain sensitivity in community-dwelling older adults with knee OA, expanding previous findings of similar cluster characterizations in healthy adults. Future research is needed to further understand the pathophysiological mechanisms underlying pain within these subgroups, which may be of added value in tailoring effective treatments for people with OA.

Evaluation of menstrual cycle effects on morphine and pentazocine analgesia

Studies have demonstrated menstrual cycle influences on basal pain perception, but direct evidence of menstrual cycle influences on analgesic responses has not been reported in humans. Our aim was to determine whether the magnitude of morphine and pentazocine analgesia varied across the menstrual cycle. Sixty-five healthy women, 35 taking oral contraceptives (OC) and 30 normally cycling (NOC), underwent experimental pain assessment both before and after intravenous administration morphine (0.08mg/kg) or pentazocine (0.5mg/kg) compared to saline placebo. Both active drug and placebo were administered once during the follicular phase and once during the luteal phase. Measures of heat, ischemic, and pressure pain sensitivity were obtained before and after drug administration. Change scores in pain responses were computed to determine morphine and pentazocine analgesic responses, and medication side effects were recorded. The data were analyzed using mixed-model analyses of variance. NOC women showed slightly greater heat pain sensitivity in the follicular vs luteal phase, while the reverse pattern emerged for OC women (P=0.046). Also, OC women showed lower pressure pain thresholds compared to NOC women (P<0.05). Regarding analgesic responses, NOC women showed greater morphine analgesia for ischemic pain during the follicular vs the luteal phase (P=0.004). Likewise, side effects for morphine were significantly higher in NOC women in the follicular phase than in the luteal phase (P=0.02). These findings suggest that sex hormones may influence opioid responses; however, the effects vary across medications and pain modalities and are likely to be modest in magnitude. Limited menstrual cycle effects on baseline pain responses were observed; however, morphine analgesia and side effects were greater during the follicular phase.

Sex pheromone production and perception in European corn borer moths is determined by both autosomal and sex-linked genes

Inheritance patterns for sex pheromone production in females, pheromone detection on male antennal olfactory receptor cells, and male pheromone behavioral responses were studied in pheromonally distinct populations of European corn borers from New York State. Gas chromatographic analyses of pheromone glands, single sensillum recordings, and flight tunnel behavioral analyses were carried out on progeny from reciprocal crosses, as well as on progeny from subsequent F(2) and maternal and paternal backcrosses. The data show that the production of the female pheromone blend primarily is controlled by a single autosomal factor, that pheromone-responding olfactory cells are controlled by another autosomal factor, and that behavioral response to pheromone is controlled by a sex-linked gene. F(1) males were found to possess olfactory receptor cells that give spike amplitudes to the two pheromone isomers that are intermediate to those of the high and low amplitude cells of the parent populations. Fifty-five percent of the F(1) males tested responded fully to pheromone sources ranging from the hybrid (E)-11-tetradecenyl acetate/(Z)-11-tetradecenyl acetate (E/Z) molar blend of 65:35 to the E/Z molar blend of 3:97 for the Z morph parents, but very few responded to the E/Z molar blend of 99:1 for the E morph parents. Data on the inheritance patterns support speculation that the Z morph is the ancestral and that the E morph is the derived European corn borer population.

Cluster analysis of multiple experimental pain modalities

Identifying individual differences in pain is an important topic; however, little is known regarding patterns of responses across various experimental pain modalities. This study evaluated subgroups emerging from multiple experimental pain measures. One hundred and eighty-eight individuals (59.0% female) completed several psychological instruments and underwent ischemic, pressure, and thermal pain assessments. Thirteen separate pain measures were obtained by using three experimental pain modalities with several parameters tested within each modality. The pain ratings and scores were submitted to factor analysis that identified four pain factors from which Pain Sensitivity Index (PSI) scores were computed: heat pain (HP), pressure pain (PP), ischemic pain (IP), and temporal summation of heat pain (TS). Cluster analyses of PSI scores revealed four distinct clusters. The first cluster demonstrated high overall pain sensitivity, the second cluster revealed high TS, the third cluster showed particular insensitivity to IP and low sensitivity across pain modalities except PP, and the fourth cluster demonstrated low sensitivity to PP. Significant correlations were found between psychological measures and Index scores and those differed by sex. Cluster membership was associated with demographic variables of ethnicity and sex as well as specific psychosocial variables, although cluster differences were only partially explained by such factors. These analyses revealed that groups respond differently across varied pain stimuli, and this was not related solely to demographic or psychosocial factors. These findings highlight the need for future investigation to identify patterns of responses across different pain modalities in order to more accurately characterize individual differences in responses to experimental pain.

Characterization of human homologs of the Drosophila seven in absentia (sina) gene

Studies of Drosophila photoreceptor development have illustrated the means by which signal transduction events regulate cell fate decisions in a multicellular organization. Development of the R7 photoreceptor is best understood, and its formation is dependent on the seven in absentia (sina) gene. We have characterized two highly conserved human homologs of sina, termed SIAH1 and SIAH2. SIAH1 maps to chromosome 16q12 and encodes a 282-amino-acid protein with 76% amino acid identity to the Drosophila SINA protein. SIAH2 maps to chromosome 3q25 and encodes a 324-amino-acid protein that shares 68% identity with Drosophila SINA and 77% identity with human SIAH1. SIAH1 and SIAH2 were expressed in many normal and neoplastic tissues, and only subtle differences in their expression were noted. However, one of three murine homologs, Siah1B, was strongly induced in fibroblasts undergoing apoptotic cell death. While a previous study suggested that SINA was a nuclear protein, epitope-tagged SINA and SIAH1 proteins were found in the cytoplasm of Drosophila and mammalian cells. Their substantial evolutionary conservation, role in specifying cell fate, and activation in apoptotic cells suggest the SIAH proteins have important roles in vertebrate development. Furthermore, given the role of sina in Drosophila photoreceptor development, SIAH2 is a candidate for the Usher syndrome type 3 gene at chromosome 3q21-q25.

Demethylation of repetitive DNA sequences in neuroblastoma

Altered genomic methylcytosine content has been described for a number of tumor types, including neuroblastoma. However, it remains to be determined for different tumor types whether specific loci or chromosomal regions are affected by a methylation change or whether the change is random. We have implemented a computer-based approach for the analysis of two-dimensional separations of human genomic restriction fragments. Through the use of methylation-sensitive restriction enzymes, methylation differences in genomic DNA between tumor and normal tissues can be detected. We report the cloning and sequencing of two fragments detectable in two-dimensional separations of genomic DNA of neuroblastomas. These fragments were found to be a part of repetitive units that exhibited demethylation in neuroblastoma relative to other tumor types. Our finding of a distinct pattern of methylation of repetitive units in neuroblastoma suggests that altered methylation at certain loci may contribute to the biology of this tumor.

Two-dimensional separation and cloning of chromosome 1 NotI-EcoRV-derived genomic fragments

The two-dimensional (2-D) separation of genomic digests has provided the means to analyze over 2000 unique restriction fragments simultaneously in a single gel, for genetic variation as well as for genomic alterations in cancer. By utilizing different combinations of restriction enzymes or different electrophoretic conditions, the number of analyzable fragments in multiple 2-D patterns can be augmented. We have previously shown the feasibility of distinguishing between spot intensities representing fragments from one allele and from two alleles and have implemented approaches for the cloning of fragments of interest in 2-D gels. In this study, the 2-D separation and cloning of chromosome 1 NotI-EcoRV-derived genomic fragments was performed. Three hundred forty-six NotI fragments in whole genomic preparations were assigned to chromosome 1. To verify the reliability of the assignment, two of the NotI fragments attributed to chromosome 1 were cloned and sequenced. The fragments that contained CpG islands were mapped by FISH to 1p35-p36.1 and to 1p13.3-p21, respectively. Our study indicates the feasibility of analyzing 2-D separations of whole genomic digests for the detection of alterations in specific chromosomes. The large number of restriction fragments attributed to chromosome 1 provides the means to screen 2-D patterns for chromosome 1 deletions and amplifications with a high marker density.

A methylated human 9-kb repetitive sequence on acrocentric chromosomes is homologous to a subtelomeric repeat in chimpanzees

We have implemented an approach for the detection of DNA alterations in cancer by means of computerized analysis of end-labeled genomic fragments, separated in two dimensions. Analysis of two-dimensional patterns of neuroblastoma tumors, prepared by first digesting DNA with the methylation-sensitive restriction enzyme Not I, yielded a multicopy fragment which was detected in some tumor patterns but not in normal controls. Cloning and sequencing of the fragment, isolated from two-dimensional gels, yielded a sequence with a strong homology to a subtelomeric sequence in chimpanzees and which was previously reported to be undetectable in humans. Fluorescence in situ hybridization indicated the occurrence of this sequence in normal tissue, for the most part in the satellite regions of acrocentric chromosomes. A product containing this sequence was obtained by telomere-anchored PCR using as a primer an oligonucleotide sequence from the cloned fragment. Our data suggest demethylation of cytosines at the cloned Not I site and in neighboring DNA in some tumors, compared with normal tissue, and suggest a greater similarity between human and chimpanzee subtelomeric sequences than was previously reported.

Hypothesis: "Rogue cell"-type chromosomal damage in lymphocytes is associated with infection with the JC human polyoma virus and has implications for oncopenesis

The hemagglutination inhibition antibody titers against the JC and BK polyoma viruses (JCV and BKV, respectively) are significantly elevated in individuals exhibiting "rogue" cells among their cultured lymphocytes. However, the elevation is so much greater with respect to JCV that the BKV elevation could readily be explained by cross reactivity to the capsid protein of these two closely related viruses. The JCV exhibits high sequence homology with the simian papovavirus, simian virus 40 (SV40), and inoculation of human fetal brain cells with JCV produces polyploidy and chromosomal damage very similar to that produced by SV40. We suggest, by analogy with the effects of SV40, that these changes are due to the action of the viral large tumor antigen, a pluripotent DNA binding protein that acts in both transcription and replication. The implications of these findings for oncogenesis are briefly discussed.

Farnesyltransferase inhibitors block the neurofibromatosis type I (NF1) malignant phenotype

Neurofibromatosis type I (NF1) is a hereditary tumor and developmental disorder whose defective gene was cloned previously. The protein product of the NF1 gene, neurofibromin, contains a domain that shows significant sequence homology to the known catalytic domains of mammalian Ras GTPase-activating proteins (GAP) and the yeast IRA1 and IRA2 proteins. This homologous region of neurofibromin has been shown to exhibit GAP activity toward Ras proteins. Malignant schwannoma cell lines from NF1 patients contain normal levels of GAP and nonmutated Ras proteins but barely detectable levels of neurofibromin, based on genetic mutations in the NF1 gene. Because these cells contain constitutively activated Ras.GTP, it has been proposed that neurofibromin may be the sole negative regulator of Ras in these cells. Overall, these results have implied an important role of the Ras signaling pathway in NF1 malignant schwannomas. Recently, several laboratories have developed small molecule inhibitors of Ras function that inhibit the enzyme farnesyltransferase (FT). FT-mediated post-translational farnesylation of Ras proteins is absolutely necessary for Ras function since this modification is required for the anchoring of Ras proteins to the plasma cell membrane. Although previous studies have shown that FT inhibitors can block the growth of tumor cells carrying mutant Ras proteins, it remained unclear how this class of inhibitors would affect tumor cells such as in NF1, whose malignant growth appears to be mediated by up-regulation of wild-type Ras activity. Thus, in the current study, we investigated whether BMS-186511, a bisubstrate analogue inhibitor of FT, would inhibit the malignant growth properties of a cell line established from malignant schwannoma of an NF1 patient. Our results indicate that the malignant growth properties of ST88-14 cells, the most malignant cell line among several well-characterized NF1 cells, are inhibited by BMS-186511 in a concentration-dependent manner. Following treatment with BMS-186511, ST88-14 cells became flat, nonrefractile, were contact-inhibited, and lost their ability to grow in soft agar. In the drug-exposed cells, Ras proteins were prevented from FT-mediated membrane association. BMS-186511 was found to specifically inhibit FT, but not geranylgeranyltransferase I, a closely related enzyme. Thus, it is conceivable that FT inhibitors may ultimately become the first generation of drugs against the malignant phenotype in NF1 based on rational insights into the mechanism of action of neurofibromin.

Mutations in L1-CAM in two families with X linked complicated spastic paraplegia, MASA syndrome, and HSAS

The suggestion that the three X linked syndromes X linked spastic paraplegia (MIM 312900), MASA syndrome (MIM 303350), and X linked hydrocephalus owing to stenosis of the aqueduct of Sylvius (MIM 307000) are variable clinical manifestations of mutations at the same locus at Xq28 was confirmed by the finding of mutations in the L1-CAM gene in the three syndromes. Recently, two families in which different subjects showed a clearly different phenotype within the same family of the three X linked syndromes were described. A reverse transcription PCR assay was developed for the analysis of the L1-CAM cDNA in two of the members of these families. RNA isolated from EBV transformed cell lines and a colon carcinoma derived cell line was used as a starting material. The L1-CAM cDNA of two male patients from each family was sequenced. We report two new mutations in the L1-CAM gene in these two families showing that the three different phenotypes observed in different generations within the same family are variable phenotypic expressions of the same mutation.

Precise localization of aphidicolin-induced breakpoints on the short arm of human chromosome 3

The common fragile site at 3p14.2 (FRA3B) has been described as the most active fragile site in the human genome. This locus may predispose chromosome 3 to specific losses due to deletions and translocations that have been associated with several malignancies, including hereditary renal cell carcinoma. We have previously described induction of breakage around FRA3B using aphidicolin in a somatic cell hybrid whose only human component was a single intact chromosome 3. That work led to the isolation of hybrids with breakpoints in the 3p13-p21.1 region with loss of all sequences distal to their respective breakpoints. In this report we describe the further characterization of the breakpoints in many of these cell lines using newly available molecular markers. We also report the identification of YAC clones that span the breakpoints present in many of these hybrids.

Clarification of chromosomal abnormalities associated with sexual ambiguity by studies with Y-chromosomal DNA sequences

Cases of gonadal dysgenesis, both Turner syndrome and mixed, were studied with Y centromeric and short-arm probes. The Y-centromeric alphoid repeat clone, Y97, allowed sensitive detection of Y-chromosomal material in marker chromosomes or mosaics by in situ analysis or Southern hybridization with purified DNA. The Y short-arm probe, p75/79, allowed detection of sequences normally associated with proximal Yp by Southern analysis. The presence of DNA fragments characteristic of Yp correlates well with partial male sexual differentiation in the cases of mixed gonadal dysgenesis. Thus, the combined use of molecular and cytogenetic techniques has proven to be a powerful approach to the analysis of chromosomal sex disorders.

Ultraviolet light induction of diphtheria toxin-resistant mutations in normal and DNA repair-deficient human and Chinese hamster fibroblasts

The role of unrepaired DNA lesions in the production of mutations is suspected of contributing to the initiation phase of carcinogenesis. Since the molecular basis of mutagenesis is not understood in eukaryotic cells, development of new genetic markers for quantitative in vitro measurement of mutations for mammalian cells is needed. Furthermore, mammalian cells, genetically deficient for various DNA repair enzymes, will be needed to study the role of unrepaired DNA lesions in mutagenesis. The results in this report relate to preliminary attempts (1) to characterize the diphtheria toxin resistance marker as a useful quantitative genetic marker in human cells and (2) to isolate and characterize various DNA repair-deficient Chinese hamster cells.