Safe management of surgical smoke in the age of COVID-19.

BACKGROUND: The COVID-19 global pandemic has resulted in a plethora of guidance and opinion from surgical societies. A controversial area concerns the safety of surgically created smoke and the perceived potential higher risk in laparoscopic surgery. METHODS: The limited published evidence was analysed in combination with expert opinion. A review was undertaken of the novel coronavirus with regards to its hazards within surgical smoke and the procedures that could mitigate the potential risks to healthcare staff. RESULTS: Using existing knowledge of surgical smoke, a theoretical risk of virus transmission exists. Best practice should consider the operating room set-up, patient movement and operating theatre equipment when producing a COVID-19 operating protocol. The choice of energy device can affect the smoke produced, and surgeons should manage the pneumoperitoneum meticulously during laparoscopic surgery. Devices to remove surgical smoke, including extractors, filters and non-filter devices, are discussed in detail. CONCLUSION: There is not enough evidence to quantify the risks of COVID-19 transmission in surgical smoke. However, steps can be undertaken to manage the potential hazards. The advantages of minimally invasive surgery may not need to be sacrificed in the current crisis.

Incidence and treatment of positive pelvic sidewall lymph nodes in patients with rectal cancer.

AIM: The involvement of pelvic sidewall (PSW) lymph nodes in rectal cancer is a marker of locally advanced disease and poor prognosis. Eastern countries generally advocate lateral lymph node dissection (LLND) over the Western approach of neoadjuvant chemoradiotherapy and more limited surgery. The aim of this study was to evaluate how these advanced cancers were treated in three UK Health Boards. METHODOLOGY: This was a retrospective review of three colorectal multidisciplinary team meetings from 2008 to 2016. All patients with rectal cancer and suspicious PSW lymph nodes on pretreatment MRI were included. RESULTS: There were 153 (6.2%) patients who met the inclusion criteria from a total of 2461 diagnosed rectal cancers. There was significant variability between the three centres with surgical intervention ranging from 59.2% to 84.4%, P = 0.015. There were 81 patients who had neoadjuvant chemoradiotherapy prior to surgery; of these 67 (82.7%) still had positive PSW nodes on the restaging MRI, but only 13 (19.4%) had LLND. There was no difference in local recurrence (15.3% vs 11.8%, P = 0.66), 5-year overall survival (69.2% vs 80.1%, P = 0.16) or 5-year disease-free survival (69.2% vs 79.4%, P = 0.72) between patients having LLND and those receiving standard neoadjuvant treatment followed by total mesorectal excision surgery. CONCLUSIONS: This study has demonstrated that rectal cancer patients with PSW positive nodal disease have advanced disease, mostly of the lower rectum, and receive a highly heterogeneous spectrum of therapies, even within a relatively small geographical area. Greater accuracy in our preoperative staging is needed to select those patients who will benefit from LLND surgery.

Telephone outreach by community workers to improve uptake of NHS Health Checks in more deprived localities and minority ethnic groups: a qualitative investigation of implementation.

BACKGROUND: NHS Health Checks is a national cardiovascular risk assessment and management programme in England. To improve equity of uptake in more deprived, and Black, Asian and minority ethnic (BAME) communities, a novel telephone outreach intervention was developed. The outreach call included an invitation to an NHS Health Check appointment, lifestyle questions, and signposting to lifestyle services. We examined the experiences of staff delivering the intervention. METHODS: Thematic analysis of semi-structured interviews with 10 community Telephone Outreach Workers (TOWs) making outreach calls, and 5 Primary Care Practice (PCP) staff they liaised with. Normalization Process Theory was used to examine intervention implementation. RESULTS: Telephone outreach was perceived as effective in engaging patients in NHS Health Checks and could reduce related administration burdens on PCPs. Successful implementation was dependent on support from participating PCPs, and tensions between the intervention and other PCP priorities were identified. Some PCP staff lacked clarity regarding the intervention aim and this could reduce the potential to capitalize on TOWs' specialist skills. CONCLUSIONS: To maximize the potential of telephone outreach to impact equity, purposeful recruitment and training of TOWs is vital, along with support and integration of TOWs, and the telephone outreach intervention, in participating PCPs.

Collaborative meta-analysis finds no evidence of a strong interaction between stress and 5-HTTLPR genotype contributing to the development of depression.

The hypothesis that the S allele of the 5-HTTLPR serotonin transporter promoter region is associated with increased risk of depression, but only in individuals exposed to stressful situations, has generated much interest, research and controversy since first proposed in 2003. Multiple meta-analyses combining results from heterogeneous analyses have not settled the issue. To determine the magnitude of the interaction and the conditions under which it might be observed, we performed new analyses on 31 data sets containing 38 802 European ancestry subjects genotyped for 5-HTTLPR and assessed for depression and childhood maltreatment or other stressful life events, and meta-analysed the results. Analyses targeted two stressors (narrow, broad) and two depression outcomes (current, lifetime). All groups that published on this topic prior to the initiation of our study and met the assessment and sample size criteria were invited to participate. Additional groups, identified by consortium members or self-identified in response to our protocol (published prior to the start of analysis) with qualifying unpublished data, were also invited to participate. A uniform data analysis script implementing the protocol was executed by each of the consortium members. Our findings do not support the interaction hypothesis. We found no subgroups or variable definitions for which an interaction between stress and 5-HTTLPR genotype was statistically significant. In contrast, our findings for the main effects of life stressors (strong risk factor) and 5-HTTLPR genotype (no impact on risk) are strikingly consistent across our contributing studies, the original study reporting the interaction and subsequent meta-analyses. Our conclusion is that if an interaction exists in which the S allele of 5-HTTLPR increases risk of depression only in stressed individuals, then it is not broadly generalisable, but must be of modest effect size and only observable in limited situations.

NHS health checks: a cross- sectional observational study on equity of uptake and outcomes.

BACKGROUND: The National Health Checks programme aims to reduce the incidence of cardiovascular diseases and health inequalities in England. We assessed equity of uptake and outcomes from NHS Health Checks in general practices in Bristol, UK. METHODS: A cross-sectional study using patient-level data, from 38 general practices. We descriptively analysed the socioeconomic status (SES) of patients invited and the SES and ethnicity of those attending. Logistic regression was used to test associations between invitation and attendance, with population characteristics. RESULTS: Between June 2010 to October 2014, 31,881 patients were invited, and 13,733 NHS Health Checks completed. 47% of patients invited from the three least and 39% from the two most-deprived index of multiple deprivation quintiles, completed a Check. Proportions of invited patients, by ethnicity were 64% non-black and Asian and 31% black and Asian. Men were less likely to attend than women (OR 0.73, 95% confidence interval 0.67 to 0.80), as were patients ≤ 49 compared to ≥ 70 years (OR 0.40, 95% confidence interval 0.65 to 0.83). After controlling for SES and population characteristics, compared to patients with low CVD risk, high risk patients were more likely to be prescribed cardiovascular drugs (OR 6.2, 95% confidence interval 4.51 to 8.40). Compared to men, women (OR 01.18, 95% confidence interval 1.03 to 1.35) were more likely to be prescribed cardiovascular drugs, as were those ≤ 49 years (50-59 years, OR 1.42, 95% confidence intervals 1.13-1.79, 60-69 years, OR 1.60, 95% confidence intervals, 1.22-2.10, ≥ 70 years, OR 1.64, 95% confidence intervals, 1.14 to 2.35). Controlling for population characteristics, the following groups were most likely to be referred to lifestyle services: younger women (OR 2.22, 95% CI 1.69 to 2.94), those in the most deprived IMD quintile (OR 3.22, 95% CI 1.63 to 6.36) and those at highest risk of CVD (OR, 2.77, 95% CI 1.91 to 4.02). CONCLUSIONS: We found no statistically significant evidence of inequity in attendance for an NHS Health Check by SES. Being older or a woman were associated with better attendance. Targeting men, younger patients and ethnic minority groups may improve equity in uptake for NHS Health Checks.

Experiences of patients and healthcare professionals of NHS cardiovascular health checks: a qualitative study.

BACKGROUND: NHS Health Checks are a national cardiovascular risk assessment and management programme in England and Wales. We examined the experiences of patients attending and healthcare professionals (HCPs) conducting NHS Health Checks. METHODS: Interviews were conducted with a purposive sample of 28 patients and 16 HCPs recruited from eight general practices across a range of socio-economic localities. Interviews were audio recorded, transcribed, anonymized and analysed thematically. RESULTS: Patients were motivated to attend an NHS Health Check because of health beliefs, the perceived value of the programme, a family history of cardiovascular and other diseases and expectations of receiving a general health assessment. Some patients reported benefits including reassurance and reinforcement of healthy lifestyles. Others experienced confusion and frustration about how results and advice were communicated, some having a poor understanding of the implications of their results. HCPs raised concerns about the skill set of some staff to competently communicate risk and lifestyle information. CONCLUSIONS: To improve the satisfaction of patients attending and improve facilitation of lifestyle change, HCPs conducting the NHS Health Checks require sufficient training to equip them with appropriate skills and knowledge to deliver the service effectively.

Primary closure or rhomboid excision and Limberg flap for the management of primary sacrococcygeal pilonidal disease? A meta-analysis of randomized controlled trials.

AIM: Sacrococcygeal pilonidal disease is a common condition afflicting the young male working and student population, resulting in considerable pain, embarrassment and loss of work days. Controversy surrounds the most appropriate surgical approach to achieve low recurrence rates whilst minimizing morbidity and permitting an early return to work. This study aims to review the published literature comparing excision followed by either primary suture or rhomboid flap repair. METHODS: PubMed, EMBASE, MEDLINE and The Cochrane Library were systematically reviewed, by two independent investigators, for relevant randomized controlled trials. Keywords and MeSH terms included 'pilonidal disease', 'primary suture/repair', 'rhomboid flap' and 'limberg/modified Limberg flap'. 'Related study' function and manuscript bibliographies were searched for further relevant studies. Study quality was assessed using the Jadad score. Meta-analysis was performed on pooled data, utilizing a random effects model when heterogeneity was high and a fixed effects model when heterogeneity was low. The primary end-point assessed was disease recurrence. Secondary end-points included wound dehiscence, pain scores, hospital stay and return to work. RESULTS: Six studies were eventually included for pooled analysis following exclusion of randomized controlled trials with poor methodology. Two studies compared 'off-midline' (Karydakis) primary suture with the Limberg flap repair. Six hundred and forty-one patients were included (331 flap repairs). Rhomboid flap excision demonstrated a trend towards less disease recurrence (P = 0.07), lower wound infection (P = 0.001) and dehiscence (P = 0.01). However, no significant difference was found for pain scores, hospital stay or return to work. CONCLUSION: The current published literature supports the use of the rhomboid flap excision and the Limberg flap-repair procedures over primary midline suture techniques for the elective management of primary pilonidal disease. Further high-quality studies are necessary to compare flap with off-midline repairs.

Association of measures of fetal and childhood growth with non-clinical psychotic symptoms in 12-year-olds: the ALSPAC cohort.

BACKGROUND: Previous studies have suggested that impaired fetal and childhood growth are associated with an increased risk of schizophrenia, but the association of pre-adult growth with non-clinical psychotic symptoms (psychosis-like symptoms) in children is not known. AIMS: To explore the associations of body size at birth and age 7.5 years with childhood psychosis-like symptoms. METHOD: Prospective cohort of children followed up from birth to age 12: the ALSPAC cohort. RESULTS: Data on 6000 singleton infants born after 37 weeks of gestation. A one standard deviation increase in birth weight was associated with an 18% reduction in the risk of definite psychosis-like symptoms after adjusting for age and gestation (Odds ratio (OR) = 0.82, 95% CI = 0.73-0.92, P = 0.001). This association was partly confounded by maternal anthropometry, smoking during pregnancy, socioeconomic status and IQ. A similar association was seen for birth length and psychosis-like symptoms, which disappeared after controlling for birth weight. There was little evidence for an association of 7-year height or adiposity with psychosis-like symptoms. CONCLUSIONS: Measures of impaired fetal, but not childhood, growth are associated with an increased risk of psychosis-like symptoms in 12-year-olds.

Investigating whether adverse prenatal and perinatal events are associated with non-clinical psychotic symptoms at age 12 years in the ALSPAC birth cohort.

BACKGROUND: Non-clinical psychosis-like symptoms (PLIKS) occur in about 15% of the population. It is not clear whether adverse events during early development alter the risk of developing PLIKS. We aimed to examine whether maternal infection, diabetes or pre-eclampsia during pregnancy, gestational age, perinatal cardiopulmonary resuscitation or 5-min Apgar score were associated with development of psychotic symptoms during early adolescence. METHOD: A longitudinal study of 6356 12-year-old adolescents who completed a semi-structured interview for psychotic symptoms in the Avon Longitudinal Study of Parents and Children (ALSPAC) birth cohort. Prenatal and perinatal data were obtained from obstetric records and maternal questionnaires completed during pregnancy. RESULTS: The presence of definite psychotic symptoms was associated with maternal infection during pregnancy [adjusted odds ratio (OR) 1.44, 95% confidence interval (CI) 1.11-1.86, p=0.006], maternal diabetes (adjusted OR 3.43, 95% CI 1.14-10.36, p=0.029), need for resuscitation (adjusted OR 1.50, 95% CI 0.97-2.31, p=0.065) and 5-min Apgar score (adjusted OR per unit decrease 1.30, 95% CI 1.12-1.50, p<0.001). None of these associations were mediated by childhood IQ score. Most associations persisted, but were less strong, when including suspected symptoms as part of the outcome. There was no association between PLIKS and gestational age or pre-eclampsia. CONCLUSIONS: Adverse events during early development may lead to an increased risk of developing PLIKS. Although the status of PLIKS in relation to clinical disorders such as schizophrenia is not clear, the similarity between these results and findings reported for schizophrenia indicates that future studies of PLIKS may help us to understand how psychotic experiences and clinical disorders develop throughout the life-course.

Human papillomavirus (HPV) and its vaccine: awareness and opinions of clinical dental students in a UK dental school.

Introduction: Dental clinicians are in a position to educate their patients on the subject of HPV as part of a primary healthcare multidisciplinary team and to detect HPV-related disease. Attention needs to be paid to dental undergraduate teaching on the topic. This study aims to ascertain awareness and opinions of our dental undergraduate students about HPV, its relation to oral health and its vaccine. Method: A questionnaire was distributed to undergraduate dental students in clinical years 3, 4 and 5 of the BDS programme at Bristol Dental School. Results: Dental students demonstrated an understanding of HPV and oropharyngeal cancer and expressed that they felt dentists should play a role in health promotion in relation to oropharyngeal cancers. They also wished for more teaching on the subject and suggested topic areas that they wished to know more about. Conclusion: New teaching strategies on the topic of HPV should be considered for inclusion into undergraduate dental programmes and encompass both knowledge and communication skills training to prepare future dentists for their role in confronting this preventable disease.

Complications of inguinal herniotomy are comparable in term and premature infants.

PURPOSE: Inguinal hernias are common, and prevalence is highest in premature males. Recognised complications include recurrence, iatrogenic cryptorchidism and testicular atrophy. We reviewed complication rates following inguinal herniotomy (IH), comparing premature (gestation <36 weeks) and term infants. METHODS: A retrospective case note review of infants aged 0-12 months undergoing IH between January 2006 and December 2010. Data collected included demographics, side of hernia, incarceration, complications, duration of follow-up and need for further surgery. Comparison was made using unpaired student t test and Fishers exact test. RESULTS: Four hundred and eight patients underwent IH (365 male, 42 female, 1 complete androgen insensitivity); 197 were premature (prem), mean weight 3.81 kg (1.02-9.4); 211 were term (gestation ≥36 weeks), mean weight 5.85 kg (2.4-11.7), p = 0.0001 versus prem. Total herniotomies performed = 472 (131 Left, 213 Right, 64 bilateral); 89 hernias were incarcerated at presentation (60 prem vs. 29 term, p = 0.0001). Bowel resection was required in six patients (5 prem vs. 1 term, p = 0.1109), and 14 had simultaneous orchidopexy (12 prem vs. 2 term, p = 0.0049). Early post-operative complication rate 2.8 % (8 prem vs. 5 term; p = 0.4037). Two hundred and forty patients attended follow-up; 58.8 % (125 prem, 115 term). This group accounted for 279 IH (264 male, 15 female). Mean follow-up = 5 months (0.5-36). Complication rates: recurrence 2.7 %, metachronous hernia 7.5 %, iatrogenic cryptorchidism 3.8 % and testicular atrophy 0.7 %. CONCLUSION: No significant difference was found in complication rates between premature and term infants despite significantly more premature infants presenting with incarcerated hernias.

Physiotherapy management of joint hypermobility syndrome--a focus group study of patient and health professional perspectives.

OBJECTIVE: To develop an understanding of patient and health professional views and experiences of physiotherapy to manage joint hypermobility syndrome (JHS). DESIGN: An explorative qualitative design. Seven focus groups were convened, audio recorded, fully transcribed and analysed using a constant comparative method to inductively derive a thematic account of the data. SETTING: Four geographical areas of the U.K. PARTICIPANTS: 25 people with JHS and 16 health professionals (14 physiotherapists and two podiatrists). RESULTS: Both patients and health professionals recognised the chronic heterogeneous nature of JHS and reported a lack of awareness of the condition amongst health professionals, patients and wider society. Diagnosis and subsequent referral to physiotherapy services for JHS was often difficult and convoluted. Referral was often for acute single joint injury, failing to recognise the long-term multi-joint nature of the condition. Health professionals and patients felt that if left undiagnosed, JHS was more difficult to treat because of its chronic nature. When JHS was treated by health professionals with knowledge of the condition patients reported satisfactory outcomes. There was considerable agreement between health professionals and patients regarding an 'ideal' physiotherapy service. Education was reported as an overarching requirement for patients and health care professionals. CONCLUSIONS: Physiotherapy should be applied holistically to manage JHS as a long-term condition and should address injury prevention and symptom amelioration rather than cure. Education for health professionals and patients is needed to optimise physiotherapy provision. Further research is required to explore the specific therapeutic actions of physiotherapy for managing JHS.

Hughes Abdominal Repair Trial (HART) - Abdominal wall closure techniques to reduce the incidence of incisional hernias: study protocol for a randomised controlled trial.

BACKGROUND: Incisional hernias are common complications of midline closure following abdominal surgery and cause significant morbidity, impaired quality of life and increased health care costs. The 'Hughes Repair' combines a standard mass closure with a series of horizontal and two vertical mattress sutures within a single suture. This theoretically distributes the load along the incision length as well as across it. There is evidence to suggest that this technique is as effective as mesh repair for the operative management of incisional hernias; however, no trials have compared the Hughes Repair with standard mass closure for the prevention of incisional hernia formation following a midline incision. METHODS/DESIGN: This is a 1:1 randomised controlled trial comparing two suture techniques for the closure of the midline abdominal wound following surgery for colorectal cancer. Full ethical approval has been gained (Wales REC 3, MREC 12/WA/0374). Eight hundred patients will be randomised from approximately 20 general surgical units within the United Kingdom. Patients undergoing open or laparoscopic (more than a 5-cm midline incision) surgery for colorectal cancer, elective or emergency, are eligible. Patients under the age of 18 years, those having mesh inserted or undergoing musculofascial flap closure of the perineal defect in abdominoperineal wound closure, and those unable to give informed consent will be excluded. Patients will be randomised intraoperatively to either the Hughes Repair or standard mass closure. The primary outcome measure is the incidence of incisional hernias at 1 year as assessed by standardised clinical examination. The secondary outcomes include quality of life patient-reported outcome measures, cost-utility analysis, incidence of complete abdominal wound dehiscence and C-POSSUM scores. The incidence of incisional hernia at 1 year, assessed by computerised tomography, will form a tertiary outcome. DISCUSSION: A feasibility phase has been completed. The results of the study will be used to inform current and future practice and potentially reduce the risk of incisional hernia formation following midline incisions. TRIAL REGISTRATION NUMBER: ISRCTN 25616490 . Registered on 1 January 2012.

Simple fundoplication versus additional vagotomy and pyloroplasty in neurologically impaired children--a single centre experience.

BACKGROUND AND AIMS: Gastrooesophageal reflux disease (GERD) is a significant problem in children with neurological impairment (NI) with high failure rates for fundoplication. Fundoplication with vagotomy and pyloroplasty (FVP) can improve the outcome by altering the sensory or motor dysfunction associated with the reflux. We report our comparative outcomes for simple fundoplication (SF) and FVP in NI children. METHODS: Case records of all patients having fundoplication under a single consultant at a tertiary UK paediatric surgical centre between January 1997 and December 2012 were retrospectively assessed for recurrent symptoms and redo surgery. The data were collected using a Microsoft Excel database and analysed on Graphpad prism software program. Data are median (range). P value<0.05 was considered significant. RESULTS: Data were available for 244 out of 275 patients who underwent fundoplication during this period (157 SF and 87 FVP). Neurological disease or known syndromes were recorded in 158 patients. Thirty-five children had congenital anatomical abnormalities. Laparoscopic fundoplication was done in 37 cases. Revisional surgery for recurrent symptoms was performed in 22 patients. In the neurologically normal children, all of whom had SF, the revision rate was 6.5%. In the NI children the revision rates were 18.5% for SF and 3.9% for FVP, respectively (Fisher's exact, P<0.05). The median time to redo surgery was 10 (1-63) months, and the median time to follow up was 19.5 (2-177) months. CONCLUSIONS: There appears to be a significantly lower need for redo surgery following FVP than SF in children with NI.

Urodynamics for Prostate Surgery Trial; Randomised Evaluation of Assessment Methods (UPSTREAM) for diagnosis and management of bladder outlet obstruction in men: study protocol for a randomised controlled trial.

BACKGROUND: Lower urinary tract symptoms (LUTS) comprise storage symptoms, voiding symptoms and post-voiding symptoms. Prevalence and severity of LUTS increase with age and the progressive increase in the aged population group has emphasised the importance to our society of appropriate and effective management of male LUTS. Identification of causal mechanisms is needed to optimise treatment and uroflowmetry is the simplest non-invasive test of voiding function. Invasive urodynamics can evaluate storage function and voiding function; however, there is currently insufficient evidence to support urodynamics becoming part of routine practice in the clinical evaluation of male LUTS. DESIGN: A 2-arm trial, set in urology departments of at least 26 National Health Service (NHS) hospitals in the United Kingdom (UK), randomising men with bothersome LUTS for whom surgeons would consider offering surgery, between a care pathway based on urodynamic tests with invasive multichannel cystometry and a care pathway based on non-invasive routine tests. The aim of the trial is to determine whether a care pathway not including invasive urodynamics is no worse for men in terms of symptom outcome than one in which it is included, at 18 months after randomisation. This primary clinical outcome will be measured with the International Prostate Symptom Score (IPSS). We will also establish whether inclusion of invasive urodynamics reduces rates of bladder outlet surgery as a main secondary outcome. DISCUSSION: The general population has an increased life-expectancy and, as men get older, their prostates enlarge and potentially cause benign prostatic obstruction (BPO) which often requires surgery. Furthermore, voiding symptoms become increasingly prevalent, some of which may not be due to BPO. Therefore, as the population ages, more operations will be considered to relieve BPO, some of which may not actually be appropriate. Hence, there is sustained interest in the diagnostic pathway and this trial could improve the chances of an accurate diagnosis and reduce overall numbers of surgical interventions for BPO in the NHS. The morbidity, and therapy costs, of testing must be weighed against the cost saving of surgery reduction. TRIAL REGISTRATION: Controlled-trials.com - ISRCTN56164274 (confirmed registration: 8 April 2014).

Evidence for impairment of behavioural inhibition in performance of operant tasks in tPA-/- mice.

We have previously shown that mice that lack the serine protease, tissue plasminogen activator (tPA), show over-responding on the active lever during time-out periods in an I.V. cocaine self-administration task. To investigate this effect further, tPA knockout mice (tPA-/-) were tested in a number of operant paradigms for a liquid food reinforcer. tPA-/- and wild-type (WT) control mice acquired a fixed ratio (FR) and a fixed interval (FI) task equally. However, extinction from the FR schedule resulted in a significant decrease in responses on the active and inactive levers in the WT mice whilst responding on the inactive lever remained high in the tPA-/- animals. In a differential reinforcement of low rate (DRL) task, tPA-/- mice acquired the task at a slower rate than WT animals. This was characterised by high levels of responding on the active lever during the first 15 sessions in the tPA-/- mice. Burst responding on the active lever (lever press rate with an inter-response time of less than 3 s) was especially high in these animals. This behaviour pattern resulted in the animals obtaining less reinforcers than the WT controls. Acute cocaine dose-dependently shifted the pattern of behaviour on the active lever towards shorter inter-response times. However, there was no difference between the tPA-/- and WT mice in their sensitivity to cocaine on this task. Repeated administration of a low dose of cocaine did not alter performance on this task in either set of animals. When the DRL task was modified to allow the tPA-/- and WT mice an equal number of reinforced trials per session there was no difference in the ability of the animals to perform the task. This would suggest that the tPA-/- mice have a tendency to over-respond but that this can be overcome when the task is modified to allow equal opportunity to learn.

Development and preliminary clinical tests of an impedance sensing VDD recording pacemaker for diagnosis and research.

Episodes of serious but infrequently occurring cardiac arrhythmias can be difficult to detect and analyse, even with modern Holter monitoring. A previous diagnostic pacemaker developed by this group provided VVI pacing therapy and recorded intracardiac ECG signals but had no atrial sensing or impedance measuring capability. A new external diagnostic pacemaker system is described that has been developed to assist in diagnosing intermittent arrhythmias by selectively recording intracardiac signals. Unlike other ambulatory monitors, in addition to recording ECG, the device combines VDD pacing therapy with the capability of monitoring and recording intracardiac impedance and pressure waveforms through a temporary intracardiac lead. A PCMCIA memory card allows storage of 48 arrhythmic events of 21 seconds each. Twelve seconds of waveform are retained before the event occurs and nine seconds after. Data retrieval and processing is performed with a PC which reconstructs each waveform for display. The ECG provides data on cardiac rhythm while cardiac function is inferred from the haemodynamic signals. During simulated trials, 14 event types were presented to the system. All events were successfully detected and recorded. During in vivo clinical tests 83 waveform recordings were made. Impedance fluctuations with typical peak-to-peak values of 64 ohms were successfully recorded.

Birth placement and child health.

The standards of health and health care for a sample of 1265 Christchurch children during the period birth to three years were examined. There was a systematic tendency for levels of health care and morbidity to vary with the child's birth placement: in general adopted children had the best standard of health care and the lowest rates of morbidity; children who entered single parent families at birth had the poorest standards of health care and the highest rates of morbidity. Statistical control for family social background including maternal age, education, ethnic status, family size and changes of residence tended to reduce the size of the observed differences. However, even when the results were controlled for these factors children in single parent families still has depressed levels of preventive health care and higher rates of hospital admission. Possible explanations of the differences are discussed.