Feasibility of Cognitive-Sparing Stereotactic Radiosurgery for Brain Metastases: Initial Report of Phase II COG-SRS Trial

PURPOSE/OBJECTIVE(S)

Radiotherapy at high doses leads to white matter (WM) and hippocampal injury which can cause cognitive decline. We designed the first, to our knowledge, evidence-based cognitive sparing brain SRS trial for patients with limited brain metastases. In this report we analyze feasibility of cognitive-sparing SRS, utilizing dose constraints for eloquent WM tracts and bilateral hippocampi.

MATERIALS/METHODS

This is a single-institution phase II NCI-funded clinical trial (NCT04343157) of cognitive-sparing brain SRS; eloquent regions of interest (ROI) and associated cognitive domains are outlined in Table 1. Patients underwent high-resolution quantitative diffusion and volumetric MRI at baseline and post-SRS follow-up. Comprehensive neurocognitive assessment was performed at baseline and 3 months post-SRS by a neuropsychologist evaluating different neurocognitive domains (Table 1). Clinical processing/workflow was largely automated with robust, validated segmentation tools of eloquent WM tracts and the hippocampi. Single fraction dose constraints to WM tracts were 12 Gy Dmax and 8.4 Gy to hippocampi with 3 and 5 fraction equivalent doses, based on our prior NTCP studies. Patient accrual, follow up imaging and neurocognitive testing is still active.

RESULTS

To date, n = 59 patients and 114 lesions have been treated with cognitive-sparing Linac-based SRS on trial. Median age is 63 years. Lung cancer was the most common primary (35.6%), along with breast cancer (23.7%) and melanoma (15.3%). Patients had 1-4 brain metastases; median prescription dose was 24 Gy/1, 27 Gy/3, or 30 Gy/5 depending on target volume. Most patients were treated < 7 business days from MRI. Cognitive endpoints have been collected on 89.5% of patients. Cognitive sparing constraints were met in 79.3% of plans while maintaining standard clinical SRS plan indices and coverage benchmarks. 38.9% of the plans that failed to meet the Dmax constraint kept D0.03cc under constraints. Plans going over constraints had tumors overlying or within 1 mm of eloquent ROIs. Local control for treated lesions at 6 months was 97.9% and 95.7% at 12 months. Distant intracranial control was 68.1% at 6 and 12 months. Median OS was 18 months.

CONCLUSION

Cognitive-sparing SRS treatment planning was successfully implemented for the majority of treated lesions with excellent local control. Mitigation of damage to eloquent structures has potential to further reduce cognitive decline after SRS. Full neurocognitive outcomes will be reported after accrual and testing are complete.

Evidence-Based Multivariate Normal Tissue Complication Probability (NTCP) Study of Domain-Specific Cognitive Decline after Partial Brain RT

PURPOSE/OBJECTIVE(S)

Beyond the hippocampus, there are no evidence-based dose constraints for eloquent brain structures which subserve memory and attention/processing speed. We performed a multivariate normal tissue complication probability analysis of post-RT neurocognitive decline, examining dosimetric predictors of eloquent brain regions.

MATERIALS/METHODS

Data were analyzed from a prospective longitudinal clinical trial. Patients (n = 78) with primary brain tumors receiving fractionated RT complete a comprehensive neurocognitive evaluation and high-resolution volumetric and diffusion MRI at baseline and 6 months post-RT. Image processing using robust, validated automated segmentation parcellated individual WM tracts, cortical regions, and hippocampi. Well-validated neurocognitive tests including Delis-Kaplan Executive Function System and Wechsler Adult Intelligence Scale-IV coding (attention/processing), Boston Naming Test (language) and Hopkins Verbal Learning Test and Brief Visuospatial Memory Test (verbal/visuospatial memory) were assessed. Reliable change indices adjusted for practice effects (RCI-PE) were calculated for each patient between baseline and 6 months; a negative RCI-PE was scored as decline. Univariate logistic regression was performed with mean and max dose to structures of interest as well as clinical variables. Multivariate model building was performed using automated bootstrapped logistic regression, LASSO and random forest modeling.

RESULTS

On univariate analysis mean and max dose to multiple regions of the corpus callosum (CC) were correlated with attention/processing speed decline; most significantly in WAIS coding, including Dmax to the anterior CC (p = 0.011) and central CC (p = 0.010), and Dmax and Dmean to the mid anterior CC (p = 0.006 and 0.010). Mean dose to the left fornix was associated with decline in memory (p = 0.023, cutoff 12.9 Gy), as were increasing age and both concurrent and adjuvant chemotherapy. On multivariate analysis for attention, automated bootstrapped logistic regression showed the most frequently selected variable was mean dose to the mid anterior CC. Performance at nested cross-validation by AUC was 0.80 (0.75-0.84); LASSO model performance by AUC was 0.76 (0.72-0.81) with Dmean to the mid anterior CC being the most frequent variable. The top five most important variables in the Random Forest as ranked by mean decrease in Gini coefficient were mean dose to mid anterior CC, all white matter, combined CC and max dose to CC and posterior CC. Model performance by AUC was 0.66 (0.60-0.71).

CONCLUSION

Here, we present the first, to our knowledge, NTCP model for decline in attention/processing speed, along with dosimetric predictors of memory decline beyond the hippocampus. We found that after partial brain RT, dose to several ROIs significantly correlated with post-RT impairment. These data can guide future cognitive-sparing strategies for brain RT.

Association between sustained virological response and clinical outcomes in patients with hepatitis C infection and hepatocellular carcinoma

Background

Sustained viral response (SVR) improves survival for patients with hepatitis C (HCV) and hepatocellular carcinoma (HCC) after curative treatment; however, the benefit of SVR in those with active HCC with a significant competing risk of mortality is unknown. This study aimed to evaluate the association between SVR and outcomes in patients with active HCC.

Methods

The authors performed a multicenter, retrospective cohort study including consecutive adults with HCV cirrhosis and treatment‐naive HCC diagnosed between 2014 and 2018. Patients were stratified into two groups: active viremia (n = 431) and SVR before HCC diagnosis (n = 135). All patients underwent nonsurgical therapy as their initial treatment and were followed until liver transplantation, last follow‐up, or death. The primary outcome was incident or worsening hepatic decompensation within 6 months and the secondary outcome was overall survival. All analyses used inverse probability of treatment weights (IPTW) to account for differences between the nonrandomized cohorts.

Results

Post‐SVR patients had significantly lower odds of hepatic decompensation compared to viremic patients (odds ratio [OR], 0.18; 95% confidence interval [CI], 0.06–0.59). Results were consistent among subgroups of patients with Child Pugh A cirrhosis (OR, 0.22; 95% CI, 0.04–0.77), Barcelona Clinic Liver Cancer stage B/C HCC (OR, 0.20; 95% CI, 0.04–0.65), and those receiving nonablative HCC therapies (OR, 0.21; 95% CI, 0.07–0.67). However, in IPTW multivariable Cox regression, SVR was not associated with improved survival (hazard ratio, 0.79; 95% CI, 0.56–1.12).

Conclusions

Patients with HCV‐related HCC and SVR are less likely to experience hepatic decompensation than viremic patients, suggesting patients with HCC who are undergoing nonsurgical therapies may benefit from DAA treatment.

Hepatitis C virus‐related hepatocellular carcinoma remains prevalent in clinical practice, however, whether treatment of hepatitis C improves outcomes is unknown. The authors have shown an association between hepatitis C sustained virological response and decreased risk of hepatic decompensation in patients with hepatocellular carcinoma, across stages of disease and types of therapy received. See also pages 000–000.

Cupriavidus spp and other waterborne organisms in healthcare water systems across the United Kingdom

BACKGROUND

Cupriavidus pauculus is a rare clinical pathogen with cases having been linked to contaminated hospital water systems. An outbreak of three cases of C. pauculus and other waterborne organisms was reported in a Glasgow hospital in 2018.

AIMS

The aim of this study was to determine whether Cupriavidus spp are present in hospital water systems elsewhere in Scotland and the UK and to ascertain the optimal laboratory methodology for detection. We also sought to establish where in the water system these organisms are detected and whether a selective media could be developed for isolation. In addition, we tested water samples for the presence of other Gram negative waterborne organisms.

METHODS

Water samples were received from ten UK NHS hospitals and from various parts of the water system. Isolates were plated on to TSA and Pseudomonas Isolation Agar and further identified using MALDI-TOF and 16S PCR FINDINGS: Cupriavidus spp. were detected in four of ten hospitals tested and all five isolates were from the periphery of the water system. All hospitals had evidence of other OPPPs. Cupriavidus spp. were identified using TSA, with some isolates growing on Pseudomonas isolation agar; as such they may be inadvertently be detected when testing water specifically for Pseudomonas aeruginosa.

CONCLUSION

This study demonstrates that isolation of Cupriavidus spp. was not unique to the Glasgow incident, these bacteria being present in hospital water systems elsewhere in the UK. We therefore recommend water testing in response to clinical cases. Consideration should also be given to water testing following bacteraemias due to other rare and unusual water borne pathogens.

A systematic review and meta-analysis of the diagnostic accuracy of biparametric prostate MRI for prostate cancer in men at risk

INTRODUCTION

Multiparametric magnetic resonance imaging (mpMRI), the use of three multiple imaging sequences, typically T2-weighted, diffusion weighted (DWI) and dynamic contrast enhanced (DCE) images, has a high sensitivity and specificity for detecting significant cancer. Current guidance now recommends its use prior to biopsy. However, the impact of DCE is currently under debate regarding test accuracy. Biparametric MRI (bpMRI), using only T2 and DWI has been proposed as a viable alternative. We conducted a contemporary systematic review and meta-analysis to further examine the diagnostic performance of bpMRI in the diagnosis of any and clinically significant prostate cancer.

METHODS

A systematic review of the literature from 01/01/2017 to 06/07/2019 was performed by two independent reviewers using predefined search criteria. The index test was biparametric MRI and the reference standard whole-mount prostatectomy or prostate biopsy. Quality of included studies was assessed by the QUADAS-2 tool. Statistical analysis included pooled diagnostic performance (sensitivity; specificity; AUC), meta-regression of possible covariates and head-to-head comparisons of bpMRI and mpMRI where both were performed in the same study.

RESULTS

Forty-four articles were included in the analysis. The pooled sensitivity for any cancer detection was 0.84 (95% CI, 0.80-0.88), specificity 0.75 (95% CI, 0.68-0.81) for bpMRI. The summary ROC curve yielded a high AUC value (AUC = 0.86). The pooled sensitivity for clinically significant prostate cancer was 0.87 (95% CI, 0.78-0.93), specificity 0.72 (95% CI, 0.56-0.84) and the AUC value was 0.87. Meta-regression analysis revealed no difference in the pooled diagnostic estimates between bpMRI and mpMRI.

CONCLUSIONS

This meta-analysis on contemporary studies shows that bpMRI offers comparable test accuracies to mpMRI in detecting prostate cancer. These data are broadly supportive of the bpMRI approach but heterogeneity does not allow definitive recommendations to be made. There is a need for prospective multicentre studies of bpMRI in biopsy naïve men.

Factors Influencing the Prevalence of Animal Cruelty During Adolescence

Adolescents' interactions with animals are of increasing interest and their beneficial developmental outcomes are well known. However, negative interactions such as perpetrating cruelty toward animals during childhood and adolescence have been related with child abuse, domestic violence, and later interpersonal violence. Cruelty toward animals by adolescents has been reported predominately in criminal and clinical samples, and links have been made between animal cruelty and interpersonal violence. However, studies often lack a clear definition of animal cruelty and the animal involved. The present study addresses methodological shortcomings by providing a clear definition of the cruelty acts and the animals involved and the time frame within which cruelty acts have been taken place. Therefore, we investigated the prevalence of animal cruelty of 979 British adolescents (419 male, 497 female, M_age = 15.1 ± 1.57 years) by means of a survey questionnaire administered in school. Animal cruelty was investigated encompassing deliberate and nondeliberate cruelty acts, a clear definition of the target animals was included and a time frame was provided. Furthermore, acceptability of animal cruelty, engaging in antisocial behavior, and family affluence were investigated. Results show high reliabilities for the measures applied. Exploratory factor analysis reveals different types of animal cruelty. Gender differences were observed for deliberate and accidental cruelty acts, with boys reporting higher levels than girls. Younger adolescents reported higher accidental cruelty acts than older ones. Acceptance of animal cruelty played a significant role in predicting animal cruelty, together with antisocial behaviors and place of living. The present study shows for the first time the importance of distinguishing between different types of animal cruelty and defining the animals involved.

Perioperative intravenous contrast administration and the incidence of acute kidney injury after major gastrointestinal surgery: prospective, multicentre cohort study

BACKGROUND

This study aimed to determine the impact of preoperative exposure to intravenous contrast for CT and the risk of developing postoperative acute kidney injury (AKI) in patients undergoing major gastrointestinal surgery.

METHODS

This prospective, multicentre cohort study included adults undergoing gastrointestinal resection, stoma reversal or liver resection. Both elective and emergency procedures were included. Preoperative exposure to intravenous contrast was defined as exposure to contrast administered for the purposes of CT up to 7 days before surgery. The primary endpoint was the rate of AKI within 7 days. Propensity score-matched models were adjusted for patient, disease and operative variables. In a sensitivity analysis, a propensity score-matched model explored the association between preoperative exposure to contrast and AKI in the first 48 h after surgery.

RESULTS

A total of 5378 patients were included across 173 centres. Overall, 1249 patients (23·2 per cent) received intravenous contrast. The overall rate of AKI within 7 days of surgery was 13·4 per cent (718 of 5378). In the propensity score-matched model, preoperative exposure to contrast was not associated with AKI within 7 days (odds ratio (OR) 0·95, 95 per cent c.i. 0·73 to 1·21; P = 0·669). The sensitivity analysis showed no association between preoperative contrast administration and AKI within 48 h after operation (OR 1·09, 0·84 to 1·41; P = 0·498).

CONCLUSION

There was no association between preoperative intravenous contrast administered for CT up to 7 days before surgery and postoperative AKI. Risk of contrast-induced nephropathy should not be used as a reason to avoid contrast-enhanced CT.

Low Vision Bicycling

This article considers bicycling as a means of transportation, not recreation, for selected individuals with low vision, and examines the skills needed to operate a bicycle in a safe and responsible manner.

Analysis of HIV Integrase Resistance in Black Men Who Have Sex with Men in the United States

Resistance to reverse transcriptase and protease inhibitors was frequently detected in HIV from black men who have sex with men (MSM) enrolled in the HIV prevention trials network (HPTN) 061 study. In this study, integrase strand transfer inhibitor (INSTI) resistance was analyzed in black MSM enrolled in HPTN 061 (134 infected at enrollment and 23 seroconverters) and a follow-up study, HPTN 073 (eight seroconverters). The ViroSeq HIV-1 Integrase Genotyping Kit (Abbott Molecular) was used for analysis. Major INSTI resistance mutations were not detected in any of the samples. HIV from 14 (8.4%) of the 165 men, including 4 (12.9%) of 31 seroconverters, had accessory or polymorphic INSTI-associated mutations. The most frequently detected mutation was E157Q. These findings are promising because INSTI-based regimens are now recommended for first-line antiretroviral treatment and because long-acting cabotegravir is being evaluated for pre-exposure prophylaxis.

Sexual Networks and HIV Risk among Black Men Who Have Sex with Men in 6 U.S. Cities

BACKGROUND

Sexual networks may place U.S. Black men who have sex with men (MSM) at increased HIV risk.

METHODS

Self-reported egocentric sexual network data from the prior six months were collected from 1,349 community-recruited Black MSM in HPTN 061, a multi-component HIV prevention intervention feasibility study. Sexual network composition, size, and density (extent to which members are having sex with one another) were compared by self-reported HIV serostatus and age of the men. GEE models assessed network and other factors associated with having a Black sex partner, having a partner with at least two age category difference (age difference between participant and partner of at least two age group categories), and having serodiscordant/serostatus unknown unprotected anal/vaginal intercourse (SDUI) in the last six months.

RESULTS

Over half had exclusively Black partners in the last six months, 46% had a partner of at least two age category difference, 87% had ≤5 partners. Nearly 90% had sex partners who were also part of their social networks. Among HIV-negative men, not having anonymous/exchange/ trade partners and lower density were associated with having a Black partner; larger sexual network size and having non-primary partners were associated with having a partner with at least two age category difference; and having anonymous/exchange/ trade partners was associated with SDUI. Among HIV-positive men, not having non-primary partners was associated with having a Black partner; no sexual network characteristics were associated with having a partner with at least two age category difference and SDUI.

CONCLUSIONS

Black MSM sexual networks were relatively small and often overlapped with the social networks. Sexual risk was associated with having non-primary partners and larger network size. Network interventions that engage the social networks of Black MSM, such as interventions utilizing peer influence, should be developed to address stable partnerships, number of partners, and serostatus disclosure.

Hoop stress and the conical connection

Dental implant-abutment connection design has developed into the use of a conical, shank and socket connection between the implant abutment and fixture. The connection between these two elements is, in effect, a conical wedge that may exert lateral forces under load that may result in fracture of the coronal implant socket fixture walls. This study evaluated the axial loading on a conical connection and found that axial loads were well tolerated but off-axial loads were not. Fracture of the implant coronal socket fixture wall occurred under off-axial loading.

β-Arrestin-2 knockout prevents development of cellular μ-opioid receptor tolerance but does not affect opioid-withdrawal-related adaptations in single PAG neurons

BACKGROUND AND PURPOSE

Tolerance to the behavioural effects of morphine is blunted in β-arrestin-2 knockout mice, but opioid withdrawal is largely unaffected. The cellular mechanisms of tolerance have been studied in some neurons from β-arrestin-2 knockouts, but tolerance and withdrawal mechanisms have not been examined at the cellular level in periaqueductal grey (PAG) neurons, which are crucial for central tolerance and withdrawal phenomena.

EXPERIMENTAL APPROACH

μ-Opioid receptor (MOPr) inhibition of voltage-gated calcium channel currents (ICa ) was examined by patch-clamp recordings from acutely dissociated PAG neurons from wild-type and β-arrestin-2 knockout mice treated chronically with morphine (CMT) or vehicle. Opioid withdrawal-induced activation of GABA transporter type 1 (GAT-1) currents was determined using perforated patch recordings from PAG neurons in brain slices.

KEY RESULTS

MOPr inhibition of ICa in PAG neurons was unaffected by β-arrestin-2 deletion. CMT impaired coupling of MOPrs to ICa in PAG neurons from wild-type mice, but this cellular tolerance was not observed in neurons from CMT β-arrestin-2 knockouts. However, β-arrestin-2 knockouts displayed similar opioid-withdrawal-induced activation of GAT-1 currents as wild-type PAG neurons.

CONCLUSIONS AND IMPLICATIONS

In β-arrestin-2 knockout mice, the central neurons involved in the anti-nociceptive actions of opioids also fail to develop cellular tolerance to opioids following chronic morphine. The results also provide the first cellular physiological evidence that opioid withdrawal is not disrupted by β-arrestin-2 deletion. However, the unaffected basal sensitivity to opioids in PAG neurons provides further evidence that changes in basal MOPr sensitivity cannot account for the enhanced acute nociceptive response to morphine reported in β-arrestin-2 knockouts.

LINKED ARTICLES

This article is part of a themed section on Opioids: New Pathways to Functional Selectivity. To view the other articles in this section visit http://dx.doi.org/10.1111/bph.2015.172.issue-2.

Trigeminal ganglion neuron subtype-specific alterations of Ca(V)2.1 calcium current and excitability in a Cacna1a mouse model of migraine

Familial hemiplegic migraine type-1 (FHM1), a monogenic subtype of migraine with aura, is caused by gain-of-function mutations in Ca(V)2.1 (P/Q-type) calcium channels. The consequences of FHM1 mutations on the trigeminovascular pathway that generates migraine headache remain largely unexplored. Here we studied the calcium currents and excitability properties of two subpopulations of small-diameter trigeminal ganglion (TG) neurons from adult wild-type (WT) and R192Q FHM1 knockin (KI) mice: capsaicin-sensitive neurons without T-type calcium currents (CS) and capsaicin-insensitive neurons characterized by the expression of T-type calcium currents (CI-T). Small TG neurons retrogradely labelled from the dura are mostly CS neurons, while CI-T neurons were not present in the labelled population. CS and CI-T neurons express Ca(V)2.1 channels with different activation properties, and the Ca(V)2.1 channels are differently affected by the FHM1 mutation in the two TG neuron subtypes. In CI-T neurons from FHM1 KI mice there was a larger P/Q-type current density following mild depolarizations, a larger action potential (AP)-evoked calcium current and a longer AP duration when compared to CI-T neurons from WT mice. In striking contrast, the P/Q-type current density, voltage dependence and kinetics were not altered by the FHM1 mutation in CS neurons. The excitability properties of mutant CS neurons were also unaltered. Congruently, the FHM1 mutation did not alter depolarization-evoked CGRP release from the dura mater, while CGRP release from the trigeminal ganglion was larger in KI compared to WT mice. Our findings suggest that the facilitation of peripheral mechanisms of CGRP action, such as dural vasodilatation and nociceptor sensitization at the meninges, does not contribute to the generation of headache in FHM1.

Subcutaneous anthrax in three intravenous drug users: a new clinical diagnosis

Anthrax is extremely rare in the western world but is endemic to areas of south and central Asia. In early 2010 an outbreak was identified in heroin-injecting intravenous drug users in the United Kingdom and Europe. Afghanistan is currently the principal source of heroin which reaches the United Kingdom. When anthrax occurs, cutaneous disease accounts for over 95% of cases. At least 47 cases with 13 deaths have been confirmed so far. We present three cases presenting during this time with marked swelling, one resulting in compartment syndrome but all with an absence of the expected cutaneous appearances. We suggest that rather than cutaneous anthrax, these patients represent a new subcutaneous presentation of anthrax.

Lessons from eleven primary health care nursing innovations in New Zealand

INTRODUCTION

In New Zealand in 2003, 11 primary health care (PHC) nursing innovation projects and an evaluation of the initiative were funded by the Ministry of Health to develop and explore the ways new models of nursing practice could help address health inequalities and contribute to PHC.

DESIGN AND METHODS

A research-and-development approach was used in the evaluation. Data were gathered from interviews with national stakeholders, workshops with personnel from all projects, visits to each project site and case studies of four projects. Analysis involved assessing each project individually as well as the projects as a whole.

CONTEXT

The initiative was one of many international and local PHC developments in this period designed to reduce health inequalities and improve patient care and health outcomes.

FINDINGS

Each project was developed from a different starting point; was located in different parts of the health system; and had different levels of funding. Some were principally focused on leading nursing development; others focused on developing nursing practice. Each involved influencing or providing nursing services, nurse education, leadership and service integration. Most projects progressed well, but some had limited success.

LESSONS

Lessons are on many levels, and include those related to: developing successful innovation; the importance of nursing leadership; developing the nursing workforce; and advancing nursing practice.

CONCLUSION

The funding of the innovative projects enabled nurses to pioneer developments. Such funding is important, as it paves the way for change and provides an opportunity for reflection and new learnings.

Compliance in the measurement of CURB-65 in patients with community acquired pneumonia and potential implications for early discharge

The CURB-65 community-acquired pneumonia (CAP) severity score is a convenient 5-variable disease-specific tool validated to predict mortality and the decision to admit. This prospective study seeks to determine (a) the accuracy CAP diagnosis; (b) the degree to which the CURB-65 score was being documented; and (c) the degree to which CURB-65 was being utilised as an admission and early discharge tool in the A&E Department in the evaluation of patients presenting with CAP. Of 45 patients referred with an admitting diagnosis of CAP, 28 were subsequently found to satisfy the criteria of CAP, an over diagnosis of 38%. Documentation of CURB-65 was 7%; recording of core variables was 81% i.e. 4 out of 5 variables and confusion was the variable least likely to be documented. On re-scoring, 50% of patients had a score of 0 or 1 and a further 28% had a score of 2. We conclude that CAP is significantly overdiagnosed; that the CURB-65 severity score is not being utilised and that between 50 and 78% of patients with CAP may be admitted unnecessarily. This study raises important issues in the current management of CAP in the Irish Healthcare system.

Towards a receptor for nocistatin?

Nocistatin is a peptide derived from the pronociceptin precursor, the source of nociceptin, the endogenous ligand for the nociceptin (NOP or ORL1). Despite nocistatin showing activity in a wide range of assays for nociception and other CNS activities, there is a dearth of information regarding the cellular actions of this peptide in the brain, and no receptor for nocistatin has been identified. In a study published in this issue of the British Journal of Pharmacology, Fantin and colleagues demonstrate that nocistatin inhibits 5-HT release from cortical synaptosomes in a concentration-dependent and Pertussis toxin-sensitive manner. The actions of nocistatin are independent of activity at NOP receptors. This study represents the first unambiguous demonstration of nocistatin agonist actions in brain and, taken together with previous work in the spinal cord, provides strong evidence that there is an as yet unidentified G protein-coupled receptor for nocistatin.

The South African stroke risk in general practice study

BACKGROUND

Incidence of stroke is increasing in sub-Saharan Africa and stroke prevention is an essential component of successful stroke management. General practitioners (GPs) are well placed to manage stroke risk factors. To design appropriate strategies for risk factor reduction we need to know the risk factor prevalence in each of the population groups attending GPs. The aim of this study was to establish the prevalence of stroke risk factors in the South African general practice population.

METHOD

We conducted a multicentre, observational study of patients attending general practice in South Africa. Two hundred general practices were randomly selected from lists provided by pharmaceutical representatives. Each GP approached 50 consecutive patients aged 30 years and older. Patients completed an information sheet and the GP documented the patient's risk factors. The resulting sample is relevant if not necessarily representative in a statistical sense.

RESULTS

A total of 9 731 questionnaires were returned out of a possible 10,000. The mean age of particpants was 50.7 years. Seventy-six per cent had 1 or more risk factors and 40% had 2 or more risk factors. Hypertension was the commonest risk factor in all population groups (55%) but was highest in black patients (59%). Dyslipidaemia was commonest in whites (37%) and least common in blacks (5%). Diabetes was commonest in Asians (24%) but least common in whites (8%). Risk factors other than smoking increased with age.

CONCLUSION

This study provides unique data on the prevalence of stroke risk factors in a South African general practice population. Risk factors are common in all population groups, but differ in distribution among the groups. There is considerable opportunity to reduce the burden of stroke in South Africa through GP screening for and treatment of risk factors.

Restorative impact of rabeprazole on gastric mucus and mucin production impairment during naproxen administration: its potential clinical significance

Rabeprazole augments gastric mucus and mucin production in humans. However, its potential restorative impact on gastric mucus and mucin production impairment, resulting from administration of naproxen, remained to be explored. Therefore, we measured the content of mucus and mucin in gastric juice (GJ) before and after administration of naproxen with rabeprazole or placebo. The study was approved by HSC at KUMC and conducted in 21 asymptomatic, H. pylori-negative volunteers in a double-blind, placebo-controlled, crossover design. The content of gastric mucus in GJ, after exhaustive dialysis and complete lyophilization, was assessed gravimetrically, whereas the content of mucin was measured after its purification with equilibrium density-gradient ultracentrifugation in CsC1. Gastric mucus secretion during administration of naproxen with placebo declined significantly both in basal (by 44%; P < 0.001) and in pentagastrin-stimulated (by 35%; P < 0.001) conditions. Coadministration of rabeprazole significantly restored the naproxen-induced impairment in mucus production in basal conditions (by 47%; P < 0.01) and by 22% during stimulation with pentagastrin. Gastric mucin secretion during naproxen/placebo administration also declined significantly in both basal (by 39%; P < 0.01) and stimulated (by 49%; P = 0.003) conditions. Rabeprazole also significantly restored the naproxen-induced decline of gastric mucin output during pentagastrin-stimulated conditions (by 67%; P = 0.003) and by 40% in basal conditions (P = 0.05). The restorative capacity of rabeprazole on the quantitative impairment of gastric mucus and mucin during administration of naproxen may translate into a clinical benefit of protection of the upper alimentary tract from NSAID-related mucosal injury.

Vitrectomy and gas for inferior break retinal detachments: are the results comparable to vitrectomy, gas, and scleral buckle?

AIMS

To compare the success rates of vitrectomy and gas with vitrectomy, gas, and buckle in the treatment of inferior break retinal detachments.

METHODS

A retrospective case note review of 86 patients who presented with inferior break retinal detachments was carried out. An inferior break was defined as a horseshoe tear present between 4 and 8 o'clock. Patients were analysed in two groups; group A consisted of 41 patients who underwent a vitrectomy and gas, group B consisted of 45 patients who underwent a vitrectomy, gas, and scleral buckle. The features of the retinal detachment, peroperative and postoperative complications, and outcomes of treatment were recorded for each patient.

RESULTS

The primary anatomical success rate at 3 months was 89% in group A versus 73% in group B (p = 0.11). There was no statistical difference in the complication rate between the two groups (p = 0.819). The most common cause of treatment failure was proliferative vitreoretinopathy, 20% (n = 9) in group B compared with 5% (n = 2) in group A and this reached statistical significance (p = 0.0159). There was a higher rate of epiretinal membrane development in group B (p = 0.0004). The final attachment rate was not statistically different between the two groups, 95% (39) in group A and 93% (42) in group B (p = 1.0).

CONCLUSION

Vitrectomy and gas without the application of a scleral buckle may be used to safely treat inferior break retinal detachments. It may be used as an alternative to vitrectomy, gas, and buckle which has an increased risk of choroidal haemorrhage, requires a longer operating time, and has all the associated complications of a scleral buckle.

The life course prospective design: an example of benefits and problems associated with study longevity

Although the life course prospective study design has many benefits, and information from such studies is in increasing demand for scientific and policy purposes, it has potential inherent design problems associated with its longevity. These are in particular the fixed sample structure and the data collected in early life, which are each determined by the scientific principles of another time and the risk over time of increased sample loss and distortion through loss. The example of a national birth cohort in Britain, studied from birth so far to age 53 years is used to address these questions. Although the response rate is high, avoidable loss, which was low in childhood, increased in adulthood, and was highest in those in adverse socio-economic circumstances and those with low scores on childhood cognitive measures. Recent permanent refusal rate rises may be the result of better tracing and/or a response to increased requests for biological measurement. Nevertheless, the responding sample continues in most respects to be representative of the national population of a similar age. Consistency of response over the study's 20 data collections has been high. The size of the sample responding in adulthood is adequate for the study of the major costly diseases, and for the study of functional ageing and its precursors. This study's continuation has depended not only on scientific value but also policy relevance. Although the problems inherent in the prospective design are unavoidable they are not, in the study described, a barrier to scientific and policy value. That seems also likely in Britain's two later born national birth cohort studies that have continued into adulthood.