Postoperative outcomes in oesophagectomy with trainee involvement

BACKGROUND

The complexity of oesophageal surgery and the significant risk of morbidity necessitates that oesophagectomy is predominantly performed by a consultant surgeon, or a senior trainee under their supervision. The aim of this study was to determine the impact of trainee involvement in oesophagectomy on postoperative outcomes in an international multicentre setting.

METHODS

Data from the multicentre Oesophago-Gastric Anastomosis Study Group (OGAA) cohort study were analysed, which comprised prospectively collected data from patients undergoing oesophagectomy for oesophageal cancer between April 2018 and December 2018. Procedures were grouped by the level of trainee involvement, and univariable and multivariable analyses were performed to compare patient outcomes across groups.

RESULTS

Of 2232 oesophagectomies from 137 centres in 41 countries, trainees were involved in 29.1 per cent of them (n = 650), performing only the abdominal phase in 230, only the chest and/or neck phases in 130, and all phases in 315 procedures. For procedures with a chest anastomosis, those with trainee involvement had similar 90-day mortality, complication and reoperation rates to consultant-performed oesophagectomies (P = 0.451, P = 0.318, and P = 0.382, respectively), while anastomotic leak rates were significantly lower in the trainee groups (P = 0.030). Procedures with a neck anastomosis had equivalent complication, anastomotic leak, and reoperation rates (P = 0.150, P = 0.430, and P = 0.632, respectively) in trainee-involved versus consultant-performed oesophagectomies, with significantly lower 90-day mortality in the trainee groups (P = 0.005).

CONCLUSION

Trainee involvement was not found to be associated with significantly inferior postoperative outcomes for selected patients undergoing oesophagectomy. The results support continued supervised trainee involvement in oesophageal cancer surgery.

Doing the right thing and getting it right: professional perspectives in social work on supporting parents from gender diverse communities

BACKGROUND

Despite significant shifts in legislative, political, cultural and social contexts, which have improved our understanding of diverse gender identities and family life, this remains under-explored within social work and social care. Trans and non-binary (TNB) parenting experiences are marginalized within mainstream professional practice and action is required to address these inequalities.

AIMS

This study explored the practices and meaning of 'parenting' and 'caring' for care professionals in families with parents with diverse gender identities in the UK. It aimed to capture a snapshot of the current state of practice knowledge and perceived practice challenges.

METHODS

A qualitative study design involving thematic analysis from detailed consultation with twenty-five relevant stakeholders in the proxy roles identified from a systematic review on what is known about trans parenting from the research evidence.

RESULTS

The complexity of systems for supporting families creates barriers to change, with a lack of training and development in the knowledge and skills of the workforce. Intersecting these themes was a strong values framework and examples of best practice provided, which social workers can use to navigate, understand, and support TNB parents and their experiences, particularly at an individual level, as a means to effect change.

DISCUSSION

Focusing on human rights, tailoring work to the specific needs of individuals and families, and affirming the diversity of family life requires professionals to take active responsibility and be more accountable in educating themselves and others on these rights. Professionals also need to reach out to the TNB community to include them in improving services as well as being active in their own organizations to ensure these are inclusive and responsive.

What do we know about transgender parenting?: Findings from a systematic review

Transgender issues are under-explored and marginalised within mainstream social work and social care professional practice. The experience of gender transition has a profound impact on the individuals who have diverse gender identities and their family members. We present findings from a systematic review of studies concerning the experiences of transgender parenting conducted during January-September 2017. We took a life course approach, examining the research studies that investigated the experience of people identifying as transgender, who were already parents at the time of their transition or who wished to be parents following transition. The review evaluated existing findings from empirical research on transgender parenting and grandparenting to establish how trans people negotiate their relationships with children following transition, and sought to consider the implications for professional practice with trans people in relation to how best to support them with their family caring roles. We used the Preferred Reporting Items for Systematic Review and Meta-Analyses (PRISMA) method. Empirical studies published from 1 January 1990 to 31 April 2017 in the English language, and which had transgender parenting as a significant focus, were included in the review. Twenty-six studies met the criteria. Key themes reported are: how trans people negotiate their relationships with children following disclosure and transition; the impact of parental transitioning on children; relationships with wider families; trans people's desires to be parents; and the role of professional practice to support trans families. We discuss how the material from the review can inform social work education and practice, including to help identify future research, education and practice priorities in this area.

The development of an instrument to measure global dimensions of maternal care in rhesus macaques (Macaca mulatta)

One of the strongest predictors of healthy child development is the quality of maternal care. Although many measures of observation and self-report exist in humans to assess global aspects of maternal care, such qualitative measures are lacking in nonhuman primates. In this study, we developed an instrument to measure global aspects of maternal care in rhesus monkeys, with the goal of complementing the individual behavioral data collected using a well-established rhesus macaque ethogram during the first months postpartum. The 22 items of the instrument were adapted from human maternal sensitivity assessments and a maternal Q-sort instrument already published for macaques. The 22 items formed four dimensions with high levels of internal reliability that represented major constructs of maternal care: (1) Sensitivity/Responsivity, (2) Protectiveness, (3) Permissiveness, and (4) Irritability. These dimensions yielded high construct validity when correlated with mother-infant frequency and duration behavior that was collected from focal observations across the first 3 postnatal months. In addition, comparisons of two groups of mothers (Maltreating vs. Competent mothers) showed significant differences across the dimensions suggesting that this instrument has strong concurrent validity, even after controlling for focal observation variables that have been previously shown to significantly differentiate these groups. Our findings suggest that this Instrument of Macaque Maternal Care has the potential to capture global aspects of the mother-infant relationship that complement individual behaviors collected through focal observations.

Interactive Methods for Teaching Action Potentials, an Example of Teaching Innovation from Neuroscience Postdoctoral Fellows in the Fellowships in Research and Science Teaching (FIRST) Program

Acquiring a faculty position in academia is extremely competitive and now typically requires more than just solid research skills and knowledge of one's field. Recruiting institutions currently desire new faculty that can teach effectively, but few postdoctoral positions provide any training in teaching methods. Fellowships in Research and Science Teaching (FIRST) is a successful postdoctoral training program funded by the National Institutes of Health (NIH) providing training in both research and teaching methodology. The FIRST program provides fellows with outstanding interdisciplinary biomedical research training in fields such as neuroscience. The postdoctoral research experience is integrated with a teaching program which includes a How to Teach course, instruction in classroom technology and course development and mentored teaching. During their mentored teaching experiences, fellows are encouraged to explore innovative teaching methodologies and to perform science teaching research to improve classroom learning. FIRST fellows teaching neuroscience to undergraduates have observed that many of these students have difficulty with the topic of neuroscience. Therefore, we investigated the effects of interactive teaching methods for this topic. We tested two interactive teaching methodologies to determine if they would improve learning and retention of this information when compared with standard lectures. The interactive methods for teaching action potentials increased understanding and retention. Therefore, FIRST provides excellent teaching training, partly by enhancing the ability of fellows to integrate innovative teaching methods into their instruction. This training in turn provides fellows that matriculate from this program more of the characteristics that hiring institutions desire in their new faculty.

Case-control study of long-term survivors of glioblastoma

e13021

Background: Survival of patients with glioblastoma (GBM) remains poor. However, a small percentage of GBM patients live ≥ 3 years. Relatively little is known about the patterns of care and outcomes of these long term survivors relative to GBM patients with standard or short-term survival. Methods: Nested case-control study of long term survivors (≥ 36 months), short term survivors (≤ 6 months) and standard survivors (> 6 months but < 36 months). Pathology was confirmed in all study subjects by a single neuropathologist. Each long term survivor (LTS) was matched to a short term survivor (STS) and 3 standard survivors (SS) by the well-established prognostic factors, age and postoperative Karnofsky Performance Status. Clinical characteristics, treatment regimens and outcomes were reviewed. Conditional logistic regression models were used to assess potential associations between baseline factors and the probability of long or short term survival. Results: Matching yielded 23 LTS with 23 STS and 69 SS. Patient characteristics are summarized in the table below. Conclusions: Controlling for the well-established prognostic factors of age and performance status, long-term GBM survivors differed significantly from short-term GBM survivors based on tumor location and extent of resection. However, there were no significant differences in baseline factors between long-term survivors versus standard survivors in this analysis. Short-term GBM survivors differed from standard survivors by tumor location and extent of resection. Molecular factors are being assessed in these groups as potential contributors to these survival differences.

[Table: see text]

[Table: see text]

Serotonin transporter gene variation, infant abuse, and responsiveness to stress in rhesus macaque mothers and infants

A functional polymorphism in the promoter region of the serotonin transporter (5-HTTLPR) gene has been associated with variation in anxiety and hypothalamus-pituitary-adrenal (HPA) axis function in humans and rhesus macaques. Individuals carrying the short allele are at a higher risk for developmental psychopathology, and this risk is magnified in short allele carriers who have experienced early life stress. This study investigated the relationship between 5-HTTLPR allelic variation, infant abuse, and behavioral and hormonal responses to stress in rhesus macaques. Subjects were 10 abusive mothers and their infants, and 10 nonabusive mother-infant pairs. Mothers and infants were genotyped for the rh5-HTTLPR, and studied in the first 6 months of infant life. For mothers and infants, we measured social group behavior, behavioral responses to handling procedures, and plasma concentrations of ACTH and cortisol under basal conditions and in response to stress tests. The proportion of individuals carrying the short rh5-HTTLPR allele was significantly higher among abusive mothers than controls. Among mothers and infants, the short allele was associated with higher basal cortisol levels and greater hormonal stress responses in the infants. In addition, infants who carried the short rh5-HTTLPR allele had higher anxiety scores than infants homozygous for the long allele. The rh5-HTTLPR genotype also interacted with early adverse experience to impact HPA axis function in the infants. These results are consistent with those of previous studies which demonstrate associations between serotonergic activity and anxiety and stress reactivity, and add additional evidence suggesting that genetic variation in serotonergic function may contribute to the occurrence of abusive parenting in rhesus macaques and modulate emotional behavior and HPA axis function.

Systematic review of the effectiveness of preventing and treating Staphylococcus aureus carriage in reducing peritoneal catheter-related infections

OBJECTIVES

To determine the clinical effectiveness and cost-effectiveness of (1) alternative strategies for the prevention of Staphylococcus aureus carriage in patients on peritoneal dialysis (PD) and (2) alternative strategies for the eradication of S. aureus carriage in patients on PD.

DATA SOURCES

Major electronic databases were searched up to December 2005 (MEDLINE Extra up to 6 January 2006).

REVIEW METHODS

Electronic searches were undertaken to identify published and unpublished reports of randomised controlled trials and systematic reviews evaluating the effectiveness of preventing and treating S. aureus carriage on peritoneal catheter-related infections. The quality of the included studies was assessed and data synthesised. Where data were not sufficient for formal meta-analysis, a qualitative narrative review looking for consistency between studies was performed.

RESULTS

Twenty-two relevant trials were found. These fell into several groups: the first split is between prophylactic trials, aiming to prevent carriage, and trials which aimed to eradicate carriage in those who already had it; the second split is between antiseptics and antibiotics; and the third split is between those that included patients having the catheter inserted before dialysis started and people already on dialysis. Many of the trials were small or short-term. The quality was often not good by today's standards. The body of evidence suggested a reduction in exit-site infections, but this did not seem to lead to a significant reduction in peritonitis, although to some extent this reflected insufficient power in the studies and a low incidence of peritonitis in them. The costs of interventions to prevent or treat S. aureus carriage are relatively modest. For example, the annual cost of antibiotic treatment of S. aureus carriage per identified carrier of S. aureus was estimated at 179 pounds (73 pounds screening and 106 pounds cost of antibiotic). However, without better data on the effectiveness of the interventions, it is not clear whether such costs are offset by the cost of treating infections and averting changes from peritoneal dialysis to haemodialysis. Although treatment is not expensive, the lack of convincing evidence of clinical effectiveness made cost-effectiveness analysis unrewarding at present. However, consideration was given to the factors needed in a hypothetical model describing patient pathways from methods to prevent S. aureus carriage, its detection and treatment and the detection and treatment of the consequences of S. aureus (e.g. catheter infections and peritonitis). Had data been available, the model would have compared the cost-effectiveness of alternative interventions from the perspective of the UK NHS, but as such it helped identify what future research would be needed to fill the gaps.

CONCLUSIONS

The importance of peritonitis is not in doubt. It is the main cause of people having to switch from peritoneal dialysis to haemodialysis, which then leads to reduced quality of life for patients and increased costs to the NHS. Unfortunately, the present evidence base for the prevention of peritonitis is disappointing; it suggests that the interventions reduce exit-site infections, but not peritonitis, although this may be due to trials being in too small numbers for too short periods. Trials are needed with larger numbers of patients for longer durations.

Maternal care patterns and behavioral development of rhesus macaque abused infants in the first 6 months of life

We investigated the maternal care patterns of rhesus macaque mothers who physically abuse their infants, and compared their infants' behavior to that of nonabused infants. Parametric and multidimensional scaling analyses indicated that abusive mothers have a distinct parenting style characterized by high rates of rejection and contact-breaking from their infants. Compared to control infants, abused infants exhibited signs of delayed independence from their mothers including higher rates of distress calls and anxiety, lower rates of contact-breaking, and differences in play. Several aspects of the abused infants' behavior were correlated with rates of abuse received during the first month, or with other maternal behaviors. These findings provide a more comprehensive characterization of the parenting styles of abusive mothers and the early behavioral development of their infants than previously available. Detailed knowledge of the early experience of abused infants is crucial for understanding possible pathological alterations in behavior and neuroendocrine function later in life.

Genetic modifiers of the Kv beta2-null phenotype in mice

Shaker-type potassium (K+) channels are composed of pore-forming alpha subunits associated with cytoplasmic beta subunits. Kv beta2 is the predominant Kv beta subunit in the mammalian nervous system, but its functions in vivo are not clear. Kv beta2-null mice have been previously characterized in our laboratory as having reduced lifespans, cold swim-induced tremors and occasional seizures, but no apparent defect in Kv alpha-subunit trafficking. To test whether strain differences might influence the severity of this phenotype, we analyzed Kv beta2-null mice in different strain backgrounds: 129/SvEv (129), C57BL/6J (B6) and two mixed B6/129 backgrounds. We found that strain differences significantly affected survival, body weight and thermoregulation in Kv beta2-null mice. B6 nulls had a more severe phenotype than 129 nulls in these measures; this dramatic difference did not reflect alterations in seizure thresholds but may relate to strain differences we observed in cerebellar Kv1.2 expression. To specifically test whether Kv beta1 is a genetic modifier of the Kv beta2-null phenotype, we generated Kv beta1.1-deficient mice by gene targeting and bred them to Kv beta2-null mice. Kv beta1.1/Kv beta2 double knockouts had significantly increased mortality compared with either single knockout but still maintained surface expression of Kv1.2, indicating that trafficking of this alpha subunit does not require either Kv beta subunit. Our results suggest that genetic differences between 129/SvEv and C57Bl/6J are key determinants of the severity of defects seen in Kv beta2-null mice and that Kv beta1.1 is a specific although not strain-dependent modifier.

Laparoscopic surgery for inguinal hernia repair: systematic review of effectiveness and economic evaluation

OBJECTIVES

To determine whether laparoscopic methods are more effective and cost-effective than open mesh methods of inguinal hernia repair, and then whether laparoscopic transabdominal preperitoneal (TAPP) repair is more effective and cost-effective than laparoscopic totally extraperitoneal (TEP).

DATA SOURCES

Electronic databases. Conference proceedings. Manufacturers' submissions to the National Institute for Clinical Excellence (NICE) were reviewed.

REVIEW METHODS

Selected studies were rigorously assessed. Dichotomous outcome data were combined using the relative risk method and continuous outcomes were combined using the Mantel-Haenszel weighted mean difference method. Time to return to usual activities was described using hazard ratios derived from individual patient data reanalysis. A review of economic evaluations undertaken by NICE in 2001 was updated and an economic evaluation was performed. The estimation of cost-effectiveness focused on the comparison of laparoscopic repair with open flat mesh. A Markov model incorporating the data from the systematic review was used to estimate cost-effectiveness for a time horizon up to 25 years.

RESULTS

Thirty-seven randomised control trials (RCTs) and quasi-RCTs met the inclusion criteria on effectiveness. Fourteen studies were included in the review of economic evaluations. Laparoscopic repair was associated with a faster return to usual activities and less persisting pain and numbness. There also appeared to be fewer cases of wound/superficial infection and haematoma. However, operation times are longer and there appears to be a higher rate of serious complications in respect of visceral (especially bladder) injuries. Mesh infection is very uncommon with similar rates noted between the surgical approaches. There is no apparent difference in the rate of hernia recurrence. Laparoscopic repair was more costly to the health service than open repair, with an estimated extra cost from studies conducted in the UK of about 300-350 pounds per patient. The point estimates of cost provided by the economic model also suggest that the laparoscopic techniques are more costly (approximately 100-200 pounds more per patient after 5 years). From the review of economic evaluations, the estimates of incremental cost per additional day at usual activities were between 86 pounds and 130 pounds. Where productivity costs were included, they eliminated the cost differential between laparoscopic and open repair. Additional analysis incorporating new trial evidence suggested that TEP was associated with significantly more recurrences than open mesh but these data did not greatly influence cost-effectiveness.

CONCLUSIONS

For the management of unilateral hernias, the base-case analysis and most of the sensitivity analysis suggest that open flat mesh is the least costly option but provides less quality adjusted life years (QALYs) than TEP or TAPP. TEP is likely to dominate TAPP (on average TEP is estimated to be less costly and more effective). It is likely that, for management of symptomatic bilateral hernias, laparoscopic repair would be more cost-effective as differences in operation time (a key cost driver) may be reduced and differences in convalescence time are more marked (hence QALYs will increase) for laparoscopic compared with open mesh repair. When possible repair of contralateral occult hernias is taken into account, TEP repair is most likely to be considered cost-effective at threshold values for the cost per additional QALY above 20,000 pounds. The increased adoption of laparoscopic techniques may allow patients to return to usual activities faster. This may, for some people, reduce any loss of income. For the NHS, increased use of laparoscopic repair would lead to an increased requirement for training and the risk of serious complications may be higher. Chronic pain should now be addressed prospectively using standard definitions and allowing assessment of the degree of pain. More evidence is required on the loss of utility caused by persisting pain and numbness, as well as serious complications resulting from minor surgery. Prospective population-based registries of new surgical procedures may be the best way to address this, as a complement to randomised trials assessing effectiveness. Further research relating to whether the balance of advantages and disadvantages changes when hernias are recurrent or bilateral is also required as current data are limited. Methodologically sound RCTs are needed to consider the relative merits and risks of TAPP and TEP. Further methodological research is required into the complexity of laparoscopic groin hernia repair and the improvement of performance that accompanies experience.

Transabdominal pre-peritoneal (TAPP) versus totally extraperitoneal (TEP) laparoscopic techniques for inguinal hernia repair: a systematic review

BACKGROUND

The choice of approach to the laparoscopic repair of inguinal hernia is controversial. There is a scarcity of data comparing the laparoscopic transabdominal preperitoneal (TAPP) approach with the laparoscopic totally extraperitoneal (TEP) approach, and questions remain about their relative merits and risks.

METHODS

Electronic databases were searched to identify reports of trials comparing laparoscopic TAPP with laparoscopic TEP. In addition, selected conference proceedings were hand-searched, websites consulted, reference lists of all included papers were scanned, and experts contacted for other potentially eligible reports. All published and unpublished randomised controlled trials and quasi-randomised controlled trials comparing laparoscopic TAPP with laparoscopic TEP for inguinal hernia repair were eligible for inclusion. Large non-randomised prospective studies were also eligible for inclusion to provide further comparative evidence of complications and serious adverse events. Two reviewers independently extracted data and assessed study quality. Statistical analyses were performed using the fixed effects model and the results expressed as relative risk (RR) for dichotomous outcomes and weighted mean difference (WMD) for continuous outcomes with 95% confidence intervals (CI).

RESULTS

The search identified one RCT which reported no statistically significant difference between TAPP and TEP when considering duration of operation, haematoma, length of stay, time to return to usual activities, and recurrence. The eight non-randomised studies suggest that TAPP is associated with higher rates of port-site hernias and visceral injuries whilst there appear to be more conversions with TEP. Vascular injuries and deep/mesh infections were rare and there was no obvious difference between the groups. No studies reporting economic evidence were identified.

CONCLUSIONS

There is insufficient data to allow conclusions to be drawn about the relative effectiveness of TEP compared with TAPP. Efforts should be made to start and complete adequately-powered randomised controlled trials (RCTs), which compare the different methods of laparoscopic repair.

Value of updating a systematic review in surgery using individual patient data

BACKGROUND

Previous research has highlighted the advantages of individual patient data (IPD) meta-analyses. However, they are resource intensive and take considerable time to complete. The aim of this study was to determine whether the extra investment is justified by greater accuracy or usefulness by means of a case study in surgery.

METHODS

An updated review using IPD, where possible, was compared with an earlier version based on aggregate published data to determine whether there were statistically significant changes in estimates of effectiveness for hernia recurrence and persisting pain. Differences related to the type of laparoscopic repair, the type of open repair and methodological quality were also explored.

RESULTS

The results for hernia recurrence changed little. However, the IPD update led to divergent conclusions for persisting pain. The published data implied a statistically significant benefit in favour of open repair, whereas the IPD result implied a statistically significant benefit in favour of laparoscopic repair (P < 0.001). Methodological quality did not account for this difference.

CONCLUSION

Updating of systematic reviews using IPD can be conducted successfully in surgery. This example led to little change in estimates of effectiveness for hernia recurrence but yielded qualitatively different estimates for persisting pain, an outcome rarely included in the published reports.

Systematic review of the clinical effectiveness and cost-effectiveness of tension-free vaginal tape for treatment of urinary stress incontinence

OBJECTIVES

To evaluate the effectiveness and cost-effectiveness of tension-free vaginal tape (TVT) in comparison with the standard surgical interventions currently used.

DATA SOURCES

Literature searches were carried out on electronic databases and websites for data covering the period 1966--2002. Other sources included references lists of relevant articles; selected experts in the field; abstracts of a limited number of conference proceedings titles; and the Internet.

REVIEW METHODS

A systematic review of studies including comparisons of TVT with any of the comparators was conducted. Alternative treatments considered were abdominal retropubic colposuspension (including both open and laparoscopic colposuspension), traditional suburethral sling procedures and injectable agents (periurethral bulking agents). The identified studies were critically appraised and their results summarised. A Markov model comparing TVT with the comparators was developed using the results of the review of effectiveness and data on resource use and costs from previously conducted studies. The Markov model was used to estimate costs and quality-adjusted life-years for up to 10 years following surgery and it incorporated a probabilistic analysis and also sensitivity analysis around key assumptions of the model.

RESULTS

Based on limited data from direct comparisons with TVT and from systematic reviews, laparoscopic colposuspension and traditional slings have broadly similar cure rates to TVT and open colposuspension, whereas injectable agents appear to have lower cure rates. TVT is less invasive than colposuspension and traditional sling procedures, and is also usually performed under regional or local anaesthesia. The principal operative complication is bladder perforation. There are currently no randomised controlled trial (RCT) data beyond 2 years post-surgery, and long-term effects are therefore currently not known reliably. TVT was more likely to be considered cost-effective compared with the other surgical procedures. Increasing the absolute probability of cure following TVT reduced the likelihood that TVT would be considered cost-effective.

CONCLUSIONS

The long-term performance of TVT in terms of both continence and unanticipated adverse effects is not known reliably at the moment. Despite relatively few robust comparative data, it appears that in the short to medium term TVT's effectiveness approaches that of alternative procedures currently available, and is of lower cost. As TVT is a less invasive procedure, it is possible that some women who would currently be managed non-surgically will be considered eligible for TVT. Increased adoption of TVT will require additional surgeons proficient in the technique. It is likely that some of the higher rates of complications, e.g. bladder perforation, reported for TVT are associated with a 'learning curve'. Appropriate training will therefore be needed for surgeons new to the operation, in respect of both the technical aspects of the procedure and the choice of women suitable for the operation. Further research suggestions include unbiased assessments of longer term performance from follow-up of controlled trials or population-based registries; more data from methodologically sound RCTs using standard outcome measures; a surveillance system to detect longer term complications, if any, associated with the use of tape; and rigorous evaluation before extending the use of TVT to women who are currently managed non-surgically.

Laparoscopic techniques versus open techniques for inguinal hernia repair

BACKGROUND

Inguinal hernia repair is the most frequently performed operation in general surgery. The standard method for inguinal hernia repair had changed little over a hundred years until the introduction of synthetic mesh. This mesh can be placed by either using an open approach or by using a minimal access laparoscopic technique. Although many studies have explored the relative merits and potential risks of laparoscopic surgery for the repair of inguinal hernia, most individual trials have been too small to show clear benefits of one type of surgical repair over another.

OBJECTIVES

The objective of this review was to compare minimal access laparoscopic mesh techniques with open techniques. Comparisons of open mesh techniques versus open non-mesh techniques have been considered in a separate Cochrane review.

SEARCH STRATEGY

We searched MEDLINE, EMBASE, and The Cochrane Central Controlled Trials Registry for relevant randomised controlled trials. The reference list of identified trials, journal supplements, relevant book chapters and conference proceedings were searched for further relevant trials. Through the EU Hernia Trialists Collaboration (EUHTC) communication took place with authors of identified randomised controlled trials to ask for information on any other recent and ongoing trials known to them. Specialists involved in research on the repair of inguinal hernia were contacted to ask for information about any further completed and ongoing trials. The world wide web was also searched.

SELECTION CRITERIA

All published and unpublished randomised controlled trials and quasi-randomised controlled trials comparing laparoscopic groin hernia repair with open groin hernia repair were eligible for inclusion. Trials were included irrespective of the language in which they were reported.

DATA COLLECTION AND ANALYSIS

Individual patient data were obtained, where possible, from the responsible trialist for all eligible studies. All reanalyses were cross-checked by the reviewers and verified by the trialists before inclusion. Where IPD were unavailable additional aggregate data were sought from trialists and published aggregate data checked and verified by the trialists. IPD were available for 25 trials, additional aggregated data for seven and published data only for nine. Where possible, time to event analysis for hernia recurrence and return to usual activities were performed on an intention to treat principle. The main analyses were based on all trials. Sensitivity analyses based on the data source and trial quality were also performed. Pre-defined subgroup analyses based on recurrent hernias, bilateral hernias and femoral hernias were also carried out.

MAIN RESULTS

41 published reports of eligible trials were included involving 7161 participants. Sample sizes ranged from 38 to 994, with follow-up from 6 weeks to 36 months. Duration of operation was longer in the laparoscopic groups (WMD 14.81 minutes, 95% CI 13.98 to 15.64; p<0001). Operative complications were uncommon for both methods but more frequent in the laparoscopic group for visceral (Overall 8/2315 versus 1/2599) and vascular (Overall 7/2498 versus 5/2758) injuries. Length of hospital stay did not differ between groups (WMD -0.04 days, 95% CI -0.08 to 0.00; p=0.05, but return to usual activity was earlier for laparoscopic groups (HR 0.56, 95%CI 0.51 to 0.61; p<0.0001 - equivalent to 7 days). The data available showed less persisting pain (Overall 290/2101 versus 459/2399; Peto OR 0.54, 95% CI 0.46 to 0.64; p<0.0001), and less persisting numbness (Overall 102/1419 versus 217/1624; Peto OR 0.38, 95% CI 0.4286 to 0.49; p<0.0001) in the laparoscopic groups. In total, 86 recurrences were reported amongst 3138 allocated laparoscopic repair and 109 amongst 3504 allocated to open repair (Peto OR 0.81, 95% CI 0.61 to 1.08; p = 0.16). The use of mesh during laparoscopic hernia repair is associated with a reduction in the risk of hernia recurrence, significantly so for the transabdominal preperitoneal repair (TAPP) versus open non-mesh repair (overall 26/1440 versus preperitoneal repair (TAPP) versus open non-mesh repair (overall 26/1440 versus 47/1119; Peto OR 0.45, 95% CI 0.28 to 0.72; p=0.0009). However, no difference was detected when comparing laparoscopic methods with open mesh methods of hernia repair.

REVIEWER'S CONCLUSIONS

The use of mesh during laparoscopic hernia repair is associated with a relative reduction in the risk of hernia recurrence of around 30-50%. However, there is no apparent difference in recurrence between laparoscopic and open mesh methods of hernia repair. The data suggests less persisting pain and numbness following laparoscopic repair. Return to usual activities is faster. However, operation times are longer and there appears to be a higher risk of serious complication rate in respect of visceral (especially bladder) and vascular injuries.

Metal on metal hip resurfacing arthroplasty. An economic analysis

This paper explores the cost utility of metal-on-metal hip resurfacing arthroplasty (MOM) as an alternative intervention to total hip replacement or 'watchful waiting' for patients with advanced hip disease. Early implant failure among younger and more active elderly patients can mean that the use of total hip replacement (THR) is delayed, with patients managed through 'watchful waiting', a combination of pain control and other non-surgical interventions. Information on costs is combined with evidence on effectiveness from a systematic review in a Markov model in order to estimate the incremental cost per quality adjusted life year (QALY) of MOM relative to THR and 'watchful waiting'.

Open mesh versus non-mesh for repair of femoral and inguinal hernia

BACKGROUND

Inguinal hernia repair is the most frequent operation in general surgery. Until recently the standard procedure has been open musculo-aponeurotic repair using sutures under tension to close the defect but 'tension-free' repair using prosthetic mesh is becoming increasingly common in many countries.

OBJECTIVES

The purpose of this review is to evaluate open mesh techniques in comparison with open non-mesh techniques for the surgical repair of groin hernia.

SEARCH STRATEGY

Electronic databases were searched and further trials were sought from the reference lists of reports of known trials. Through the EU Hernia Trialists Collaboration authors of identified randomised controlled trials were asked for information on any other trials known to them. There was no language restriction.

SELECTION CRITERIA

Studies were eligible for inclusion if they were randomised or quasi-randomised trials comparing either a) open mesh with open non-mesh repair of groin hernia or b) open flat mesh repair with plug and mesh repair of groin hernia.

DATA COLLECTION AND ANALYSIS

For each outcome the results were derived using data from the best available source. The majority of data for this review came from individual patient data (IPD) supplied by the trialists. When these were unavailable data came from additional aggregated information or from published trial reports. All trials were analysed using the 'intention to treat' principle.

MAIN RESULTS

Twenty trials comparing open mesh with open non-mesh repair were identified. Open mesh methods, on average, took 7-10 minutes less to perform than Shouldice procedures, but took 1-4 minutes longer than other non-mesh methods. There were no clear differences between mesh and non-mesh groups for haematomas, seromas or wound/superficial infections. Three serious operative complications were reported after open mesh repair and three following non-mesh repair. Overall, those in the mesh groups had a shorter length of hospital stay and quicker return to usual activities, but this pattern was not observed for all trials. There was a suggestion that persisting pain was less frequent after mesh repair than after non-mesh repair but this result was dependent on one trial and data were not available for 11 trials. There was no evidence of a difference between the groups with respect to persisting numbness. Fewer hernia recurrences were reported after mesh repair (Peto OR: 0.37, 95% CI: 0.26 to 0.51). There were too few data to reliably address differential effects for patients with recurrent, bilateral or femoral hernias. Two trials comparing flat mesh with plug and mesh were identified. There was no clear evidence of differences between the groups.

REVIEWER'S CONCLUSIONS

There is evidence that the use of open mesh repair is associated with a reduction in the risk of recurrence of between 50% and 75%. Although the trials were heterogeneous there is also some evidence of quicker return to work and of lower rates of persisting pain following mesh repair.

Methodological issues using household budget survey expenditure data for individual food availability estimation: Irish experience in the DAFNE pan-European project. DAta Food NEtworking

OBJECTIVE

Irish participation in the EU-supported DAta Food NEtworking (DAFNE) project required compliance with the overall aims and objectives. The Irish Household Budget Survey (HBS) expenditure data had to be transformed into a format compatible with the collaborative effort, by converting them into quantities of foodstuffs available per person per day.

SETTING

The Irish 1987 HBS expenditure data on all commodities for 7705 households in the Republic of Ireland, collected using a 14-day diary kept by all members of the household aged 15 years and over.

DESIGN

Following identification of 188 food items in the HBS dataset, retail prices per unit weight were sought for each food. Adjustment of prices, collected from a number of different sources, was made to those of 1987 using the Consumer Price Index. Simple models were used to estimate household food availability through application of the adjusted retail prices per unit weight to the expenditure data. The household level data were converted to food availability per person per day. An internal validation of quantities estimated using the retail prices was made using the 12 foodstuffs for which the Irish HBS collects expenses and quantities.

RESULTS

The comparison of quantities published by the Irish Central Statistics Office for 12 foodstuffs in the Irish 1987 Household Budget Survey with the quantities estimated using equivalent expenditure data and corresponding retail prices showed agreement, with less than a 10% margin of error for 10 of the foods.

CONCLUSION

In spite some difficulty in converting HBS food expenditure data into food availability per person per day, the DAFNE approach is potentially useful for Irish nutrition surveillance purposes and for facilitating comparisons of the Irish HBS food data with those of other European countries.

Light therapy for seasonal affective disorder in primary care: randomised controlled trial

BACKGROUND

Studies of light therapy have not been conducted previously in primary care.

AIMS

To evaluate light therapy in primary care.

METHOD

Fifty-seven participants with seasonal affective disorder were randomly allocated to 4 weeks of bright white or dim red light. Baseline expectations for treatment were assessed. Outcome was assessed with the Structured Interview Guide for the Hamilton Depression Scale, Seasonal Affective Disorder Version.

RESULTS

Both groups showed decreases in symptom scores of more than 40%. There were no differences in proportions of responders in either group, regardless of the remission criteria applied, with around 60% (74% white light, 57% red light) meeting broad criteria for response and 31% (30% white light, 33% red light) meeting strict criteria. There were no differences in treatment expectations.

CONCLUSIONS

Primary care patients with seasonal affective disorder improve after light therapy, but bright white light is not associated with greater improvements.

Assay of topically administered ibuprofen using a model of post-injury hypersensitivity. A randomised, double-blind, placebo-controlled study

OBJECTIVE

To develop a reliable assay for quantifying the analgesic efficacy of non-steroidal anti-inflammatory drugs (NSAIDs) using a model that is accepted as a paradigm of clinical pain.

SUBJECTS

Fifteen normal subjects, all of whom were volunteers from medical school staff, took part in the study.

METHODS

Capsaicin (20 microl) in solution (0.03 mg/ml) was applied to the volar surface of the forearm, and the skin was maintained at a constant temperature using a thermal stimulator. The magnitude of the surrounding area of mechanical allodynia to a brush stimulus (i.e. a clinical correlate of tenderness to touch) was assessed. Under double-blind, placebo-controlled conditions, the test was repeated using skin previously treated with ibuprofen gel or placebo.

RESULTS

A close linear relationship was observed between skin temperature over a range of 30 degrees C to 40 degrees C and the area of capsaicin-induced allodynia. Ibuprofen gel significantly reduced (P < 0.004) the area of touch-evoked allodynia at a constant skin temperature of 40 degrees C.

CONCLUSIONS

The thermal-facilitated adaptation of the capsaicin model described in this study represents an inexpensive and reliable assay for the effects of topical formulations of NSAID upon mechanical sensitivity. As such, it is a potential alternative to many clinical studies in which inherent confounding and bias can preclude a meaningful conclusion.

Comparative analgesic effects of H-wave therapy and transcutaneous electrical nerve stimulation on pain threshold in humans

OBJECTIVE

To assess the comparative analgesic efficacy of H-wave therapy (HWT) and transcutaneous electrical nerve stimulation (TENS) using a mechanical model of pain threshold measurement.

STUDY DESIGN

Forty-eight healthy human volunteers (24 women, 24 men) were recruited and randomly assigned into one of six experimental groups; control, HWT (placebo, 2Hz, or 60Hz), or TENS (placebo or 110Hz). For each subject, mechanical pain threshold (MPT) measurements were recorded at three standardized recording points marked on the dorsal web space of the dominant hand. Two MPT measurements were recorded at each point at the following time intervals: before treatment was initiated (baseline), after each of three consecutive 10-minute periods of stimulation (HWT or TENS), and at four intervals within 30 minutes after stimulation. In the control and placebo groups MPT measurements were recorded at similar time intervals.

RESULTS

Difference scores, calculated from patients' baseline values, were analyzed by ANOVA for each of the three recording points. Although results showed a significant increase in MPT levels in all three stimulation groups when compared with their relative placebo (indicating a hypoalgesic effect), no differences were observed between the different modalities or HWT frequencies. Significant hypoalgesia continued for 5 minutes after stimulation.

CONCLUSION

The findings showed that HWT and TENS provided localized hypoalgesia during stimulation and for up to 5 minutes after it. No frequency- or modality-specific effects were observed between the groups.

The effects of Shaker beta-subunits on the human lymphocyte K+ channel Kv1.3

The activation of T-lymphocytes is dependent upon, and accompanied by, an increase in voltage-gated K+ conductance. Kv1.3, a Shaker family K+ channel protein, appears to play an essential role in the activation of peripheral human T cells. Although Kv1.3-mediated K+ currents increase markedly during the activation process in mice, and to a lesser degree in humans, Kv1.3 mRNA levels in these organisms do not, indicating post-transcriptional regulation. In other tissues Shaker K+ channel proteins physically associate with cytoplasmic beta-subunits (Kvbeta1-3). Recently it has been shown that Kvbeta1 and Kvbeta2 are expressed in mouse T cells and that they are up-regulated during mitogen-stimulated activation. In this study, we show that the human Kvbeta subunits substantially increase K+ current amplitudes when coexpressed with their Kv1.3 counterpart, and that unlike in mouse, protein levels of human Kvbeta2 remain constant upon activation. Differences in Kvbeta2 expression between mice and humans may explain the differential K+ conductance increases which accompany T-cell proliferation in these organisms.

Transcutaneous electrical nerve stimulation: effect on peripheral nerve conduction, mechanical pain threshold, and tactile threshold in humans

OBJECTIVES

To investigate the effect of different transcutaneous electrical nerve stimulation (TENS) parameters on nerve conduction in the human superficial radial nerve and on peripheral mechanical pain threshold (MPT) and tactile threshold (TT), and to further the current knowledge of the neurophysiologic effects of TENS.

STUDY DESIGN

Fifty healthy human subjects were randomly allocated in equal numbers to a control group or one of four TENS groups to receive electrical stimulation consisting of four combinations of TENS pulse durations (50microsec and 200microsec) and frequencies (4Hz and 110Hz). In the TENS groups, TENS was applied under double-blind conditions for 15 minutes over the superficial radial nerve in the dominant forearm. Over a 1-hour period, compound action potentials, MPT readings, and TT readings were recorded bilaterally.

RESULTS

Only one combination of TENS parameters (110Hz, 200microsec) effected consistent changes in all of the variables assessed, ie, TENS produced a significant increase in negative peak latency while simultaneously increasing both MPT and TT.

CONCLUSION

The findings from this study suggest that at least part of TENS-mediated hypoalgesia is a consequence of a direct peripheral effect of TENS, although a "central" effect may not be excluded.

Localization of two potassium channel beta subunit genes, KCNA1B and KCNA2B

The gating properties and current amplitudes of mammalian voltage-activated Shaker potassium channels are modulated by at least two associated beta subunits (Kv beta 1.1 and Kv beta 1.2). The human Kv beta 1.1 gene (KCNA1B) resides on chromosome 3, as indicated by somatic cell hybrid mapping. More precise localization of KCNA1B to 3q26.1 was obtained with fluorescence in situ hybridization (FISH) and was corroborated by PCR screening of the CEPH YAC library. The human Kv beta 1.2 gene (KCNA2B) resides on chromosome 1, as indicated by somatic cell hybrid mapping, and has been localized by FISH to 1p36.3.

Alternative splicing of the human Shaker K+ channel beta 1 gene and functional expression of the beta 2 gene product

Mammalian voltage-activated Shaker K+ channels associate with at least three cytoplasmic proteins: Kv beta 1, Kv beta 2 and Kv beta 3. These beta subunits contain variable N-termini, which can modulate the inactivation of Shaker alpha subunits, but are homologous throughout an aldo-keto reductase core. Human and ferret beta 3 proteins are identical with rat beta 1 throughout the core while beta 2 proteins are not; beta 2 also contains a shorter N-terminus and has no reported physiological role. We report that human beta 1 and beta 3 are derived from the same gene and that beta 2 modulates the inactivation properties of Kv1.4 alpha subunits.

A characterization of the activating structural rearrangements in voltage-dependent Shaker K+ channels

In response to changes in membrane potential, voltage-dependent ion channel proteins undergo conformational rearrangements that lead to channel opening. These rearrangements move a net charge, measured as "gating current", across the membrane. Here we characterize the effects of the pharmacological blocker 4-aminopyridine on both the K+ and gating currents of wild-type and mutant Shaker K+ channels. Our results indicate that the activation of these channels involves two distinct types of structural rearrangement. In addition to independent Hodgkin and Huxley type rearrangements for each of the four subunits, which are responsible for most of the gating charge movement, Shaker channels interconvert between two quaternary conformations during activation. The transition between the two quaternary states moves about 10% of the total gating charge, and it is selectively blocked by 4-aminopyridine.

The spinal actions of nonsteroidal anti-inflammatory drugs and the dissociation between their anti-inflammatory and analgesic effects

The traditional classification of nonsteroidal anti-inflammatory drugs (NSAIDs) as exclusively 'peripherally acting' agents is no longer valid. For many of these agents there is a growing body of evidence in favour of an additional central mechanism for their anti-inflammatory and analgesic effects. This view is further supported by the recent discovery that a substantial component of the hyperalgesia and allodynia that characterise postinjury hypersensitivity occurs in the CNS, notably the spinal dorsal horn. An important corollary is that inhibition of central nociceptive processing may represent an important analgesic mode of action for those NSAIDs that are effective in the management of pain after tissue injury. Historically, attempts to group this heterogeneous class of compounds into a single entity are largely derived from the observation that the majority of clinically useful NSAIDs are weak organic acids (pKa 3 to 5), bind extensively to plasma albumin (= 99%), and inhibit (to varying degrees) prostaglandin synthesis. However, the significance of these various unifying features is becoming increasingly obscure. While inhibition of prostaglandin synthesis apparently remains an important analgesic mode of action for NSAIDs both in the periphery and the CNS, other mechanisms should be considered. Some NSAIDs, in addition to their effects on prostaglandin synthesis, also affect the synthesis and activity of other neuroactive substances believed to have key roles in processing nociceptive input within the dorsal horn. It has been argued that these other actions, in conjunction with inhibition of prostaglandin synthesis, may synergistically augment the effects of NSAIDs on spinal nociceptive processing. Despite much effort, it remains a formidable task to assess the significance of these differential mechanisms upon clinical pain states. In the meantime, however, it may be possible, on the basis of in vivo studies, to evaluate the impact of putative spinal analgesic mechanisms that are unrelated to inhibition of prostaglandin synthesis. This approach has recently been extended to include the identification of pharmacokinetic and clinical correlates of these derived in vivo parameters, and in this way attempt to demonstrate clinical relevance.

Cerebral asymmetry and hypnosis: a signal-detection analysis of divided visual field stimulation

Brightness discriminations in a divided-field paradigm were examined with a signal-detection procedure in three sessions, the second with hypnosis. Practiced, hypnotically susceptible Ss were subdivided into high- (n = 6) and medium- (n = 5) susceptible groups on the basis of a susceptibility scale monitored throughout the hypnosis session. High-susceptible Ss showed increases in d' in the left visual field (right hemisphere) with hypnosis, whereas medium-susceptible Ss showed bilateral enhancements. Beta remained invariant in both groups across three sessions but was higher in the left visual field. The results provide evidence of altered brain function with hypnosis and an association of focal right hemispheric changes with high susceptibility and, through the invariance of beta, fail to support the attribution of perceptual changes to attitudinal, nonstate factors.

Substitution of a hydrophobic residue alters the conformational stability of Shaker K+ channels during gating and assembly

A leucine residue at position 370 (L370) in 29-4 Shaker K+ channels resides within two overlapping sequence motifs conserved among most voltage-gated channels: the S4 segment and a leucine heptad repeat. Here we investigate the effects observed upon substitution of L370 with many other uncharged amino acid residues. We find that smaller or more hydrophilic residues produce greater alterations in both activation and inactivation gating than does substitution with other large hydrophobic residues. In addition, subunits containing less conservative substitutions at position 370 are restricted in their assembly with wild-type subunits and are unlikely to form homomultimeric channel complexes. Consistent with the idea that L370 influences the tertiary structure of these channels, the results indicate that L370 undergoes specific hydrophobic interactions during the conformational transitions of gating; similar interactions may take place during the folding, insertion, or assembly of Shaker K+ channel subunits.

Cerebral asymmetry and hypnosis: a signal-detection analysis of divided visual field stimulation

Brightness discriminations in a divided-field paradigm were examined with a signal-detection procedure in three sessions, the second with hypnosis. Practiced, hypnotically susceptible Ss were subdivided into high- (n = 6) and medium- (n = 5) susceptible groups on the basis of a susceptibility scale monitored throughout the hypnosis session. High-susceptible Ss showed increases in d' in the left visual field (right hemisphere) with hypnosis, whereas medium-susceptible Ss showed bilateral enhancements. Beta remained invariant in both groups across three sessions but was higher in the left visual field. The results provide evidence of altered brain function with hypnosis and an association of focal right hemispheric changes with high susceptibility and, through the invariance of beta, fail to support the attribution of perceptual changes to attitudinal, nonstate factors.

Tandem linkage of Shaker K+ channel subunits does not ensure the stoichiometry of expressed channels

Shaker K+ channels are multimeric, probably tetrameric proteins. Substitution of a conserved leucine residue to valine (V2) at position 370 in the Drosophila Shaker 29-4 sequence results in large alterations in the voltage dependence of gating in the expressed channels. In order to determine the effects of this mutation in hybrid channels with a fixed stoichiometry of V2 and wild-type (WT) subunits we generated cDNA constructs of two linked-monomeric subunits similar to the tandem constructs previously reported by Isacoff, E. Y., Y. N. Jan, and L. Y. Jan. (1990. Nature (Lond.). 345:530-534). In addition, we constructed a tandem cDNA containing a wild-type subunit and a truncated nonfunctional subunit (Sh102) that suppresses channel expression. We report that the voltage-dependence of the channels produced with WT and V2 subunits varied significantly with the order of the subunits in the construct (WT-V2 or V2-WT), while the WT-Sh102 construct yielded currents that were much larger than expected. These results suggest that the tandem linkage of Shaker subunits does not guarantee the stoichiometry of the expressed channel proteins.

The size of gating charge in wild-type and mutant Shaker potassium channels

The high sensitivity of voltage-gated ion channels to changes in membrane potential implies that the process of channel opening is accompanied by large charge movements. Previous estimates of the total charge displacement, q, have been deduced from the voltage dependence of channel activation and have ranged from 4 to 8 elementary charges (e0). A more direct measurement of q in Drosophila melanogaster Shaker 29-4 potassium channels yields a q value of 12.3 e0. A similar q value is obtained from mutated Shaker channels having reduced voltage sensitivity. These results can be explained by a model for channel activation in which the equilibria of voltage-dependent steps are altered in the mutant channels.

Dissociation between the antinociceptive and anti-inflammatory effects of the nonsteroidal anti-inflammatory drugs. A survey of their analgesic efficacy

The authors challenge the general view that the analgesic effect of the nonsteroidal anti-inflammatory drugs (NSAIDs) can be universally attributed to their inhibitory effects on the synthesis of peripherally formed prostaglandins. Analgesic activity by some of these compounds in the reduction of physiological pain elicited by a single noxious stimulus, or the treatment of acute pain which results from sudden trauma to otherwise healthy tissue, is better described as an antinociceptive effect. Single-dose studies in the dental pain model that have been conducted in double-blind conditions and included a placebo control group have been reviewed; those NSAIDs which are significantly superior to the reference compound aspirin 650mg and those which could represent real alternatives to the use of narcotics in certain situations for the management of acute pain have been identified. Azapropazone, diflunisal, naproxen, oxaprozin and tolmetin are all weak inhibitors of prostaglandin synthesis, yet they have been shown to be more effective than aspirin. In a model of joint pain, azapropazone 600mg has been shown to be as effective as pethidine (meperidine) 100mg despite being the weakest inhibitor of prostaglandin synthesis. Whether the antinociceptive effect of azapropazone acts at a peripheral or a central level, or both, is not clear; evidence for the effects of NSAIDs on the central nervous system (CNS) is discussed. Historically, the antinociceptive character of some NSAIDs is apparent in several studies in both animals and humans. More recently, experimental algesimetry models designed to distinguish the antinociceptive effects of NSAIDs include the use in humans of photoplethysmography and computer-supported infrared thermographic imaging.

A role for hydrophobic residues in the voltage-dependent gating of Shaker K+ channels

A leucine heptad repeat is well conserved in voltage-dependent ion channels. Herein we examine the role of the repeat region in Shaker K+ channels through substitution of the leucines in the repeat and through coexpression of normal and truncated products. In contrast to leucine-zipper DNA-binding proteins, we find that the subunit assembly of Shaker does not depend on the leucine heptad repeat. Instead, we report that substitutions of the leucines in the repeat produce large effects on the observed voltage dependence of conductance voltage and prepulse inactivation curves. Our results suggest that the leucines mediate interactions that play an important role in the transduction of charge movement into channel opening and closing.

Shaker K+ channel subunits from heteromultimeric channels with novel functional properties

A large number of related genes (the Sh gene family) encode potassium channel subunits which form voltage-dependent K+ channels by aggregating into homomulitimers. One of these genes, the Shaker gene in Drosophila, generates several products by alternative splicing. These products encode proteins with a constant central region flanked by variable amino and carboxyl domains. Coinjection of two Shaker RNAs with different amino or different carboxyl ends into Xenopus oocytes produces K+ currents that display functional properties distinct from those observed when each RNA is injected separately, indicating the formation of heteromultimeric channels. The analysis of Shaker heteromultimers suggests certain rules regarding the roles of variable amino and carboxyl domains in determining kinetic properties of heteromultimeric channels. Heteromultimers with different amino ends produce currents in which the amino end that produces more inactivation dominates the kinetics. In contrast, heteromultimers with different carboxyl ends recover from inactivation at a rate closer to that observed in homomultimers of the subunit which results in faster recovery. While this and other recent reports demonstrate that closely related Sh family proteins form functional heteromultimers, we show here that two less closely related Sh proteins do not seem to form functional heteromultimeric channels. The data suggest that sites for subunit recognition may be found in sequences within a core region, starting about 130 residues before the first membrane spanning domain of Shaker and ending after the last membrane spanning domain, which are not conserved between Sh Class I and Class III genes.

The amphiprotic character of azapropazone and its relevance to the gastric mucosa

Since most non-steroidal anti-inflammatory drugs (NSAIDs) contain only one obvious ionisable group at physiological pH levels then they may be easily identified as having either acidic or basic character. Basic NSAIDs are simply non-acidic NSAIDs capable of accepting a proton within the physiological pH range. Within this range, however, a few NSAIDs contain two obvious ionisable groups, one acidic and the other basic. Such compounds should be described as amphiprotic, and include NSAIDs such as 4- and 5-amino substituted salicylic acids, niflumic acid, amfenac, WY 18251, and azapropazone. The aqueous ionisation equilibrium of such compounds is complex and is described by two macroscopic ionisation constants. Evidence has accumulated during the last decade to support the view that the pharmacokinetic behaviour of NSAIDs contributes not only decisively to their therapeutic effects but also to the type and incidence of their side-effects. A priori, using a physicochemical argument, certain amphiprotic NSAIDs should be better tolerated by the gastric mucosa than the classical acidic compound. Of those NSAIDs commercially available in the United Kingdom azapropazone remains the only one for which amphiprotic behaviour has been described. Following our examination of available data for azapropazone we conclude that the use of amphiprotic compounds represents a logical approach towards solving the problem of NSAID-induced gastric mucosal damage.

Multiple hairy pacinian neurofibromas (nerve-sheath myxomas)

Pacinian neurofibromas are unusual tumors with components that resemble Vater-Pacini corpuscles and are probably a variant of nerve-sheath myxoma. Lesions composed predominantly of these structures have occurred on or near the buttocks in three previously reported cases; however, all were solitary and congenital. Two of these patients, with lesions that closely resembled mature Vater-Pacini corpuscles, had underlying skeletal anomalies. Our patient had multiple hairy pacinian neurofibromas (nerve-sheath myxomas) on the buttocks that were not associated with radiographic evidence of and underlying skeletal anomaly. Skeletal anomalies may be associated with "sacrococcygeal paciniomas" but probably not with true pacinian neurofibromas.

Classical absorption theory and the development of gastric mucosal damage associated with the non-steroidal anti-inflammatory drugs

Evidence has accumulated during the last decade to support the view that the pharmacokinetic behaviour of non-steroidal anti-inflammatory drugs (NSAIDs) contributes not only decisively to their therapeutic effects but also to the type and incidence of their side effects. It has been shown that NSAIDs reach particularly high concentrations in those compartments in which they cause effects and side effects. Specifically, the data reviewed herein indicate that the accumulation of NSAID within gastric mucosal cells a priori is a principal factor associated with the intervention of intracellular biochemical events and resultant gastric mucosal damage. To a large extent this behaviour is according to the precepts of classical absorption theory; in this respect the limitations of such theory are examined. Our survey further indicates that the failure of certain NSAIDs to significantly reduce gastric mucosal levels of prostaglandins (PG) in vivo may reflect pharmacokinetic differences between NSAIDs rather than tissue-specific differences in their potency as inhibitors of cyclo-oxygenase.

Prognostic indicators of tumor response to Staphylococcus aureus Cowan strain I plasma perfusion

Ten tumor-bearing dogs were treated with passage of autologous plasma over fixed Staphylococcus aureus Cowan strain I. Five similar dogs were treated identically except for the exposure to S. aureus. These animals have been assessed to identify positive and negative prognostic variables for response. Nonresponder treated animals had significantly larger chest wall tumor bulk than did the responder and control groups (P less than .01). Responder animals had fewer initial circulating immune complexes than did the nonresponders, though each group had similar reductions in immune complexes with therapy. Nonresponder animals had smaller volumes of plasma processed per kilogram of body weight per procedure than did controls (P = .016), whereas responder and control animals had similar volumes processed per kilogram of body weight per procedure (P = .84). These data suggest that the response observed in our original series was significantly related to the larger amount of plasma treated per procedure and suggest that a factor may be eluted from the S. aureus cartridge that mediates this response.