Multianalyte Prognostic Signature Including Circulating Tumor DNA and Circulating Tumor Cells in Patients With Advanced Pancreatic Adenocarcinoma

PURPOSE

Pancreatic ductal adenocarcinoma (PDAC) is associated with a poor prognosis. Multianalyte signatures, including liquid biopsy and traditional clinical variables, have shown promise for improving prognostication in other solid tumors but have not yet been rigorously assessed for PDAC.

MATERIALS AND METHODS

We performed a prospective cohort study of patients with newly diagnosed locally advanced pancreatic cancer (LAPC) or metastatic PDAC (mPDAC) who were planned to undergo systemic therapy. We collected peripheral blood before systemic therapy and assessed circulating tumor cells (CTCs), cell-free DNA concentration (cfDNA), and circulating tumor KRAS (ctKRAS)-variant allele fraction (VAF). Association of variables with overall survival (OS) was assessed in univariate and multivariate survival analysis, and comparisons were made between models containing liquid biopsy variables combined with traditional clinical prognostic variables versus models containing traditional clinical prognostic variables alone.

RESULTS

One hundred four patients, 40 with LAPC and 64 with mPDAC, were enrolled. CTCs, cfDNA concentration, and ctKRAS VAF were all significantly higher in patients with mPDAC than patients with LAPC. ctKRAS VAF (cube root; 0.05 unit increments; hazard ratio, 1.11; 95% CI, 1.03 to 1.21; P = .01), and CTCs ≥ 1/mL (hazard ratio, 2.22; 95% CI, 1.34 to 3.69; P = .002) were significantly associated with worse OS in multivariate analysis while cfDNA concentration was not. A model selected by backward selection containing traditional clinical variables plus liquid biopsy variables had better discrimination of OS compared with a model containing traditional clinical variables alone (optimism-corrected Harrell's C-statistic 0.725 v 0.681).

CONCLUSION

A multianalyte prognostic signature containing CTCs, ctKRAS, and cfDNA concentration outperformed a model containing traditional clinical variables alone suggesting that CTCs, ctKRAS, and cfDNA provide prognostic information complementary to traditional clinical variables in advanced PDAC.

Phase II Study of Maintenance Rucaparib in Patients With Platinum-Sensitive Advanced Pancreatic Cancer and a Pathogenic Germline or Somatic Variant in BRCA1, BRCA2, or PALB2

PURPOSE

Olaparib, a poly (ADP-ribose) polymerase (PARP) inhibitor (PARPi), is approved as maintenance therapy for patients with advanced pancreatic cancer (PC) and a germline BRCA1 or BRCA2 pathogenic variant (PV). This investigator-initiated, single-arm phase II study assessed the role of the PARPi rucaparib as maintenance therapy in advanced PC with germline or somatic PV in BRCA1, BRCA2, or PALB2.

PATIENTS AND METHODS

Eligible patients had advanced PC; germline (g) or somatic (s) PVs in BRCA1, BRCA2, or PALB2, and received at least 16 weeks of platinum-based chemotherapy without evidence of platinum resistance. Chemotherapy was discontinued and patients received rucaparib 600 mg orally twice a day until progression. The primary end point was the progression-free survival (PFS) rate at 6 months (PFS6). Secondary end points included safety, ORR, disease control rate, duration of response, and overall survival.

RESULTS

Of 46 enrolled patients, 42 were evaluable (27 gBRCA2, seven gBRCA1, six gPALB2, and two sBRCA2). PFS6 was 59.5% (95% CI, 44.6 to 74.4), median PFS was 13.1 months (95% CI, 4.4 to 21.8), and median overall survival was 23.5 months (95% CI, 20 to 27). The PFS at 12 months was 54.8%. ORR of the 36 patients with measurable disease was 41.7% (3 complete responses; 12 partial responses; 95% CI, 25.5 to 59.2), and disease control rate was 66.7% (95% CI, 49.0 to 81.4). Median duration of response was 17.3 months (95% CI, 8.8 to 25.8). Responses occurred in patients with gBRCA2 (41%, 11 out of 27), gPALB2 (50%, 3 out of 6), and sBRCA2 (50%, 1 out of 2). No new safety signals were noted.

CONCLUSION

Maintenance rucaparib is a safe and effective therapy for platinum-sensitive, advanced PC with a PV in BRCA1, BRCA2, or PALB2. The finding of efficacy in patients with gPALB2 and sBRCA2 PVs expands the population likely to benefit from PARPi beyond gBRCA1/2 PV carriers.

Abstract CT234: A Phase II, single arm study of maintenance rucaparib in patients with platinum-sensitive advanced pancreatic cancer and a pathogenic germline or somatic mutation in BRCA1, BRCA2 or PALB2

Background: PARP inhibitors have activity in multiple BRCA-related malignancies and have recently demonstrated dramatic efficacy as a maintenance strategy for platinum-sensitive ovarian cancer. Between 5-8% of patients with pancreatic cancer (PC) have a pathogenic mutation in BRCA1, BRCA2 or PALB2. Therefore, we initiated a single arm phase II clinical trial of maintenance monotherapy rucaparib in patients with advanced PC and a pathogenic germline or somatic BRCA or PALB2 mutation, whose cancer had not progressed following at least four months of platinum-based chemotherapy (NCT 03140670).

Methods: Patients were enrolled and treated with rucaparib 600mg PO BID until disease progression or unacceptable toxicity. The primary endpoint is progression free survival (PFS). Patients have previously received >4 months of platinum-based chemotherapy without evidence of disease progression. However, patients with a medical contraindication to receiving the full four months of platinum have been permitted to enroll at the discretion of the primary investigator. Responses were determined using RECIST v1.1.

Results: As of December 31st, 2018, we have enrolled 24 of the planned 42 patients, of which 19 are evaluable for PFS at the time of this interim analysis. For these patients, the mutational distribution includes: 13 germline BRCA2, 3 germline BRCA1, 2 germline PALB2, 1 somatic BRCA2. Patients were predominantly female (84.2%) with a median age of 61 years (range: 35-81). Patients had received a median of four months (range 0.5-32 months) of prior platinum therapy for advanced disease. All patients were evaluable for toxicity. Overall, treatment with rucaparib was well tolerated without dose limiting toxicities. The most common adverse events that were at least possibly related to treatment included nausea (grade 1, 41.6%; grade 2, 4.2%), dysgeusia (grade 1, 33.3%) and fatigue (grade 1, 25%). One patient required dose reduction for nausea. The median PFS was 9.1 months from the start of rucaparib therapy with an ORR of 36.8% (six PRs; one CR). Disease control rate (CR + PR + SD) was 89.5% for at least eight weeks. Two patients (10.5%) had progressive disease at first follow-up scan two months after beginning treatment. Eight patients have been on rucaparib for >6 months and two patients remain on treatment for >1 year (13 months and 15 months). The seven responding patients include those with germline BRCA2 mutations (4 patients), germline PALB2 mutations (2 patients) and somatic BRCA2 mutation (1 patient).

Conclusions: Based on these early data, maintenance rucaparib following induction with platinum-based chemotherapy shows encouraging disease control with minimal toxicity in patients with platinum-sensitive advanced PC and a pathogenic mutation in BRCA1, BRCA2 or PALB2.

Citation Format: Kim A. Reiss Binder, Rosemarie Mick, Mark O'Hara, Ursina Teitelbaum, Thomas Karasic, Charles Schneider, Peter J. O'Dwyer, Erica Carpenter, Austin Pantel, Mehran Makvandi, David Mankoff, Katherine Nathanson, Kara Maxwell, Stacy Cowden, Mary Jane Fuhrer, Janae Romeo, Gregory L. Beatty, Susan Domchek. A Phase II, single arm study of maintenance rucaparib in patients with platinum-sensitive advanced pancreatic cancer and a pathogenic germline or somatic mutation in BRCA1, BRCA2 or PALB2 [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr CT234.

Combining Machine Learning and Nanofluidic Technology To Diagnose Pancreatic Cancer Using Exosomes

Circulating exosomes contain a wealth of proteomic and genetic information, presenting an enormous opportunity in cancer diagnostics. While microfluidic approaches have been used to successfully isolate cells from complex samples, scaling these approaches for exosome isolation has been limited by the low throughput and susceptibility to clogging of nanofluidics. Moreover, the analysis of exosomal biomarkers is confounded by substantial heterogeneity between patients and within a tumor itself. To address these challenges, we developed a multichannel nanofluidic system to analyze crude clinical samples. Using this platform, we isolated exosomes from healthy and diseased murine and clinical cohorts, profiled the RNA cargo inside of these exosomes, and applied a machine learning algorithm to generate predictive panels that could identify samples derived from heterogeneous cancer-bearing individuals. Using this approach, we classified cancer and precancer mice from healthy controls, as well as pancreatic cancer patients from healthy controls, in blinded studies.

A magnetic micropore chip for rapid (<1 hour) unbiased circulating tumor cell isolation and in situ RNA analysis

The use of microtechnology for the highly selective isolation and sensitive detection of circulating tumor cells has shown enormous promise. One challenge for this technology is that the small feature sizes - which are the key to this technology's performance - can result in low sample throughput and susceptibility to clogging. Additionally, conventional molecular analysis of CTCs often requires cells to be taken off-chip for sample preparation and purification before analysis, leading to the loss of rare cells. To address these challenges, we have developed a microchip platform that combines fast, magnetic micropore based negative immunomagnetic selection (>10 mL h^-1) with rapid on-chip in situ RNA profiling (>100× faster than conventional RNA labeling). This integrated chip can isolate both rare circulating cells and cell clusters directly from whole blood and allow individual cells to be profiled for multiple RNA cancer biomarkers, achieving sample-to-answer in less than 1 hour for 10 mL of whole blood. To demonstrate the power of this approach, we applied our device to the circulating tumor cell based diagnosis of pancreatic cancer. We used a genetically engineered lineage-labeled mouse model of pancreatic cancer (KPCY) to validate the performance of our chip. We show that in a cohort of patient samples (N = 25) that this device can detect and perform in situ RNA analysis on circulating tumor cells in patients with pancreatic cancer, even in those with extremely sparse CTCs (<1 CTC mL^-1 of whole blood).

Crop row detection in maize fields inspired on the human visual perception

This paper proposes a new method, oriented to image real-time processing, for identifying crop rows in maize fields in the images. The vision system is designed to be installed onboard a mobile agricultural vehicle, that is, submitted to gyros, vibrations, and undesired movements. The images are captured under image perspective, being affected by the above undesired effects. The image processing consists of two main processes: image segmentation and crop row detection. The first one applies a threshold to separate green plants or pixels (crops and weeds) from the rest (soil, stones, and others). It is based on a fuzzy clustering process, which allows obtaining the threshold to be applied during the normal operation process. The crop row detection applies a method based on image perspective projection that searches for maximum accumulation of segmented green pixels along straight alignments. They determine the expected crop lines in the images. The method is robust enough to work under the above-mentioned undesired effects. It is favorably compared against the well-tested Hough transformation for line detection.

Associations of physical activity and fitness with adipocytokines in adolescents: the AFINOS Study

BACKGROUND AND AIMS

Adipocytokines may have a key role in the development of atherosclerosis and type 2 diabetes. The purpose of this study was to examine the independent and joint associations of physical activity (PA), cardiorespiratory fitness (CRF) and muscular fitness (MF) with adiponectin and leptin in adolescents.

METHODS AND RESULTS

A sample of 198 adolescents (96 girls), aged 13-17-year, was selected. Participants completed anthropometric measurements (height, weight, and waist circumference) and percentage of body fat (%BF) was estimated by bioelectrical impedance. PA was measured by accelerometer for 7-day. The 20-m shuttle-run test was used to assess CRF and two MF tests (handgrip strength and standing broad jump) were used to create an MF score. A cluster score of health status (0-3 risks) was created. Serum adiponectin and plasma leptin were also determined. Regression analyses controlling for age, sex, pubertal status and waist circumference showed that PA was not significantly associated with adiponectin and vigorous PA showed a significant inverse association with leptin. Both CRF and MF were significantly and inversely associated with adiponectin and leptin. Further analyses revealed that the 'healthy' group (0 risks) had significantly lower adiponectin and leptin than 'medium-healthy' (1 risk) and 'unhealthy' (2-3 risks) status groups.

CONCLUSIONS

PA, CRF and MF are inversely and jointly associated with adiponectin and leptin concentrations in adolescents.

Daily consumption of milk enriched with fish oil, oleic acid, minerals and vitamins reduces cell adhesion molecules in healthy children

BACKGROUND AND AIMS

Several studies have suggested that polyunsaturated fatty acids, vitamins and minerals have beneficial effects on lipid profile and systemic inflammation in adults.

METHODS AND RESULTS

We examined the effects of a daily intake of milk enriched with longchain polyunsaturated fatty acids, oleic acid, carbohydrates, vitamins, minerals and low in saturated fatty acids (SFAs) for 5 months, on several cardiovascular (CVD) risk biomarkers in healthy children aged 8-14 years. In a randomized double-blind placebo-controlled trial, a total of 107 children of both genders were assigned to two study groups: 1) a supplemented group (SG, n=53) who consumed 0.6 L/day of an enriched dairy product, and 2) a control group (CG, n=54) who consumed 0.6 L/day of standard whole milk. Both groups consumed the dairy drinks for 5 months, in addition to their usual diet. Serum levels of adhesion molecules as indices of vascular endothelial cell activation were assessed in both groups at 0 and 5 months as well as white blood cell counts, lipid profile, serum proteins, total serum calcium, 25-OH vitamin D, glucose, insulin and adiponectin. In the enriched dairy drink supplemented group, adhesion molecules E-selectin and ICAM-1 as well as lymphocyte levels decreased while plasma docosahexaenoic acid (DHA) and serum calcium concentrations increased. In the control group, serum total protein, transferrin, total cholesterol, HDL-cholesterol and adiponectin concentrations decreased.

CONCLUSION

The consumption of a milk enriched with fish oil, oleic acid, minerals and vitamins reduced indices of endothelial cell activation in the studied group of healthy children.

Immunomodulatory effect of fibres, probiotics and synbiotics in different life-stages

Chronic diseases associated to modern lifestyle habits are usually related to immune system malfunction. In this context, since diet is very well-known to modulate host resistance to infectious and inflammatory processes, the consumption of fibre and probiotics seems to be a promising nutritional tool for immune system modulation in different populations. Health effects of dietary fibres and probiotics have been extensively documented in numerous epidemiological and intervention studies, especially their beneficial effect on intestinal microbiota with important clinical implications in the prevention and/or treatment of infectious and inflammatory diseases. Mechanisms may include modulation of the functional properties of the microbiota, epithelial cells, dendritic cells and immune cell types. Prebiotics have been extensively reported to affect the composition of the gut microbiota, stimulating directly or indirectly putative beneficial gut commensals other than lactic acid bacteria, opening promising areas of research for the discovery of new probiotic strains and synbiotic combinations. Age-related changes in gut physiology, microbiota and mucosal immune response are well established. Moreover, exposure to different challenges during life such as early encounter of environmental insults in the newborn, infant formula feeding, antibiotic treatment, gastrointestinal diseases and stress, also interferes with the normal development and balance of the healthy gut microbiota. Therefore, the current short review gives an overview of today's main aspects of the effect of fibres, probiotics and synbiotics on the immune system in different life-stages.

Is soft drink consumption associated with body composition? A cross-sectional study in Spanish adolescents

OBJECTIVES

Published data about the association between the consumption of sweetened soft-drinks (SSD) and obesity in childhood are controversial and still inconsistent. In addition, data are lacking in the Spanish population. The purpose of this study was therefore, to explore the cross-sectional association between body composition-related parameters and SSD consumption in Spanish adolescents.

SUBJECTS AND METHODS

A representative sample of 1,523 adolescents (768 boys and 755 girls), with complete dietary data as well as anthropometric measurements, were included in this study. Weight, height, waist circumferences, and 6 skinfolds were measured, and BMI and percentage body fat were calculated. From a 24h dietary recall the subjects were grouped in 3 groups according to their SSD consumption: 1) Non-consumers (0 g of SSD consumption); 2) Moderate consumption (< 336 g/day of SSD, equivalent to the average SSD portion size); and 3) High consumption (> 336 g/day of SSD).

RESULTS

67% males and 75% females did not consume any SSD the day before the dietary recall interview. Males consumed more SSD than females. Regarding the association between SSD consumption and measures of obesity, no difference was observed between the three groups of SSD consumption in any of the anthropometric measurement, BMI or body fat.

CONCLUSION

As no association was present between SSD consumption and obesity in our cross-sectional study we suggest that dietary patterns and habits as well as lifestyle factors such as physical activity should be present when examining cross-sectional or longitudinal relationships with obesity. Multidisciplinary intervention studies are crucial when trying to develop solutions against the increasing obesity epidemic.

[Does beer have an impact on weight gain? Effects of moderate beer consumption on body composition]

BACKGROUND

The effects of alcohol consumption on body weight have been evaluated in a large number of studies suggesting to be inversely as well as positively related to body weight and body fat.

OBJECTIVE

This study examined the relationships between moderate beer consumption and anthropometrical parameters in Spanish healthy adults.

METHOD

After a 30 day alcohol abstemious period, 58 healthy volunteers were submitted to a daily moderate consumption of beer during the following 30 days. Weight, height, skinfolds and circumferences were measured at three points: (a) basal; (b) abstemious and (c) after moderate consumption of beer.

RESULTS

Biceps skinfold (mm) increased (p < 0.05) in men after moderate beer consumption in regard to abstinence period (5.74 +/- 1.70 vs. 6.23 +/- 1.74). No significant differences were observed in the rest of anthropometrical parameters studied in both women and men along the study intervention.

CONCLUSION

Moderate beer consumption during one month did not mostly change weight and weight-related parameters in healthy adults.

Two-stage treatment with preoperative endoscopic retrograde cholangiopancreatography (ERCP) compared with single-stage treatment with intraoperative ERCP for patients with symptomatic cholelithiasis with possible choledocholithiasis

BACKGROUND AND STUDY AIMS

An ideal treatment for choledocholithiasis in the laparoscopic era has not been established. The objective of this study was to elucidate whether a treatment strategy of performing intraoperative endoscopic retrograde cholangiopancreatography (ERCP) during laparascopic cholecystectomy (when choledocholithiasis is confirmed by intraoperative cholangiography) is better for patients with suspected common bile duct stones than the current strategy (preoperative ERCP followed by laparoscopic cholecystectomy).

PATIENTS AND METHODS

This was a prospective randomized study to evaluate which of these two approaches was most benefit- and cost-effective for patients with intermediate risk of choledocholithiasis. Patients underwent either preoperative ERCP followed by a laparoscopic cholecystectomy a few weeks later (the "preoperative ERCP" group) or intraoperative ERCP (the "intraoperative ERCP" group). Intraoperative ERCP was performed using the rendezvous technique.

RESULTS

There were 64 patients in the preoperative ERCP group and 59 patients in the intraoperative ERCP group. The demographic and clinical characteristics of the two groups were similar, except that the bilirubin and gamma-glutamyl transferase (GGT) levels and the number of patients treated on an inpatient basis were higher in the preoperative ERCP group. Success rates were similar (96.6 % in the preoperative ERCP group vs. 90.2 % in the intraoperative ERCP group in the per-protocol study). Total morbidity, post-ERCP morbidity, and post-ERCP acute pancreatitis rates were higher in the preoperative ERCP group, but there were no differences between the two groups in the frequency of residual common bile duct stones, the conversion rate to open cholecystectomy, or surgical morbidity. The length of hospital stay and costs were lower in the intraoperative ERCP group despite the longer surgical times in this group. Univariate analysis did not find any relationship between morbidity and total bilirubin or GGT. Logistic regression analysis confirmed that morbidity was related only to the treatment group and the time spent in the operating room: the relative risk (RR) was 4.37 for morbidity and 1.015 for the time spent in the operating room); the RR for papillotomy was 5.49.

CONCLUSIONS

Both treatment approaches were equally effective but the intraoperative ERCP group had less morbidity, a shorter hospital stay, and reduced costs. The lower morbidity in the intraoperative ERCP group resulted from the lower rate of papillotomy and lower rates of post-ERCP pancreatitis and cholecystitis. Total morbidity was principally related to the type of treatment approach used.

[Contribution to the intake of macro and micro nutrients exerted by moderate beer consumption]

OBJECTIVE

Moderate beer consumption can be part of a healthy diet, like the Mediterranean diet. The aim of the present study was to analyse the contribution a moderate beer consumption makes to energy and nutrient intake in Spanish healthy adults.

MATERIAL AND METHODS

As part of a larger intervention study, dietary intake was measured by means of a 7-day food dietary record in 24 men and 22 women (age 34.18 +/- 5.80 years) twice: during the last week of the 30 days of complete alcohol abstinence and during the last week of 30 days of moderate beer consumption. Energy and nutrient content of food was analysed by means of the GEA program, based on the Spanish food composition tables.

RESULTS

In women, moderate beer consumption increased significantly (p < 0.05) mean vitamin B6 (1.24 +/- 0.32 to 1.47 +/- 0.34 mg), B12 (3.87 +/- 1.46 to 5.58 +/- 2.76 microg), A (614.45 +/- 224.75 to 788.3 +/- 486.1 microg), and folate (139.5 +/- 39.88 to 168.25 +/- 56.32 microg) intake, whereas there was a decrease in mean iodine intake (327.1 +/- 148.4 to 281.2 +/- 135.02 microg). In men, mean vitamin B2 (1.64 +/- 0.62 to 1.91 +/- 0.46 mg), B6 (1.54 +/- 0.63 to 1.80 +/- 0.37 mg), niacin (30.01 +/- 8.13 to 34.78 +/- 6.26 mg) and folate (153.23 +/- 68.70 to 192.32 +/- 46.73 mg) intake also increased significantly. Energy, macronutrient and mineral intake had non-significant oscillations.

CONCLUSION

Moderate beer consumption can improve diet quality in regard to B vitamins in healthy adults.

Influence of alcohol consumption on immunological status: a review

The aim of this review is to present and discuss the effect of different levels of alcohol consumption on the immune system. Not only the amount consumed but also the type of alcoholic beverage have to be taken into account in order to determine the consequences on activity, number, distribution, balance, interaction and response of immunocompetent cells. The association between alcohol exposure and the risk of developing an alcohol-related disease is multifactorial. In fact, age, gender, smoking habits, dietary intake and exercise are involved among other factors. The evaluation of the host cellular and humoral immune responses has shown that alcohol may induce some benefits when consumption is moderate. Moreover, those alcoholic beverages that contain antioxidants, such as red wine, could be protectors against immune cell damage. According to the literature consulted, the daily consumption of 10-12 g and 20-24 g of alcohol for women and men, respectively, is considered to be a moderate intake; the type of beverage has been established not to be important when defining moderation. Particular attention is often focused on the U- or J-shaped curve which also suggests that light to moderate drinking produces a protective effect. Such an inverse relationship indicates a reduction of risk for both light and moderate consumers and a higher risk not only for hard drinkers, but also for non-consumers.

Limitation of Tat-associated transcriptional processivity in HIV-infected PBMC

The ability of HIV to match levels of viral mRNA to the activation state of the host cell may play a role in its ability to persist as well as to replicate. This linkage depends on the function of the viral transcriptional regulatory protein, Tat, which increases the efficiency of RNA elongation (transcriptional processivity) in response to cellular activation. To quantify levels of Tat function in vivo, a quantitative competitive RT-PCR assay was developed that reflects levels of TAR leader fragments (nonprocessive transcripts) and viral mRNA (processive transcripts), indicating low or high levels of Tat function, respectively. The abundance of these RNA species was measured in peripheral blood mononuclear cells (PBMC) of 22 HIV-1-positive individuals (CD4(+) T cell counts 63-934/mm3) and in established cell line models of HIV constitutive replication (H9IIIB) and reversible latency (U1 and ACH-2). In PBMC, the level of total viral transcripts ranged over four orders of magnitude; however, nonprocessive transcription predominated: 70% of PBMC samples had a ratio of processive to total transcripts of <0.3 and none of the samples had 100% processivity. The cell line studies revealed that, even in activated H9IIIB cells, nonprocessive transcription dominates and that latently infected cells can have different transcriptional responses to activation. This is the first study that enumerates degrees of transcriptional processivity in the circulating mononuclear cell compartment and the results suggest that limitation of Tat function may be a common phenotype throughout the course of the disease.

Understanding physicians' imaging test use in low back pain care: the role of focus groups

OBJECTIVE

To gain understanding about why a controlled intervention to reduce variability in lumbar spine imaging test use rates for low back pain patients was ineffective among internal medicine and family practice physicians in a large US health maintenance organization.

DESIGN

We retrospectively analyzed data from focus groups that had been conducted prior to the implementation of the intervention. The physicians were asked about the factors that influence their decisions to order such tests.

STUDY PARTICIPANTS

Internal medicine and family practice physicians in the intervention group. MAIN STUDY FINDINGS: Most of the variability in physicians' imaging test ordering appeared to occur in the care of patients with back pain of non-traumatic origin who had no radicular symptoms. Within that clinical context, nonclinical factors such as patient age and work status, time constraints, access problems and ambiguity about internal referral processes were important factors in physicians' decisions. Especially relevant were tensions and conflicts the physicians face as they attempted to meet conflicting role obligations in the health maintenance organization. These tensions raised issues of patient trust in their physicians and in medical care organizations, and it appeared that imaging test orders sometimes served social and symbolic functions in resolving them.

CONCLUSION

Our findings suggest that gaining information from focus groups prior to designing physician behavior change interventions may aid the design of more effective interventions.

Primary care physicians' use of lumbar spine imaging tests: effects of guidelines and practice pattern feedback

OBJECTIVE

To reduce variability in primary care physicians' use of procedures for imaging the lumbar spine.

DESIGN

Controlled intervention using clinical practice guideline and practice pattern feedback.

STUDY SAMPLE

Sixty-seven internists and 28 family practitioners in a large, group-model HMO.

MEASUREMENTS AND MAIN RESULTS

Intervention group physicians received the clinical practice guideline for low back pain, followed after 4 months by three bimonthly feedback reports on their current use rates for lumber spine x-rays and computed tomography and magnetic resonance imaging scans of the lumbar spine. Control group physicians received neither the guideline nor the feedback reports. Automated radiology utilization data were used to compare intervention and control group physicians' changes in use rates and variability in use rates over the course of the study period. Neither the guideline alone nor the guideline plus feedback was associated with a significant decrease in use rates or in the variability in use rates for the lumbar spine imaging procedures under study.

CONCLUSIONS

Clinical practice guidelines and practice pattern feedback fail to achieve their goals when features of the practice setting and patient expectations and behavior are not identified and addressed.

Intracranial pressure and outcome in adult encephalitis

The relationship between intracranial pressure (ICP) and outcome was studied in 10 adults with encephalitis. Eight had biopsy-proven herpes simplex encephalitis, one had acute hemorrhagic leukoencephalitis, and in one case the cause of encephalitis was unknown. Monitoring of ICP was instituted because of clinical deterioration or computerized tomography evidence of brain swelling, and was begun a mean of 7 days after the onset of symptoms and continued for a mean of 9 days. All five survivors, but only one of the five fatalities, had an initial ICP of less than 12 mm Hg (p less than 0.05). Four patients with a mean daily ICP of less than 20 mm Hg survived, whereas five of six patients with higher ICP's died (p less than 0.05). Peak ICP did not occur until the 12th day of illness on average. The Glasgow Coma Scale score at the time the ICP monitor was inserted did not correlate with outcome. Intracranial pressure monitoring in severe encephalitis may be a useful adjunct for therapy and an indicator of prognosis.

Postcoital contraception with levonorgestrel during the peri-ovulatory phase of the menstrual cycle. Task Force on Post-ovulatory Methods for Fertility Regulation

The contraceptive efficacy and side effects of postcoital levonorgestrel used repeatedly during the peri-ovulatory period of one cycle was examined in 259 women. All subjects were of proven fertility in their present union and had ovulatory cycles as assessed from pre-treatment BBT charts. The mean number of coital acts during the treatment cycle was 7.5 (SD:2.6) and the mean number of 0.75 mg levonorgestrel tablets taken during the peri-ovulatory period was 4.0 (SD:1.2). Two pregnancies, both considered to be method failures, occurred, giving a failure rate of 0.8% per treated cycle. Although the overall effect of levonorgestrel on menstrual cycle length was small and insignificant, menstrual cycle disturbances were not uncommon. Intermenstrual bleeding or spotting occurred in 8.5% of the treated cycles and 12.5% of the cycles were less than 20 or more than 35 days. Other side effects, mainly nausea, headache and dizziness, were reported by about 20% of the subjects but the apparent incidence of these complaints varied markedly between the nine participating centres from 0% to just over 50%. The data suggest that repeated postcoital use of levonorgestrel is probably not a viable approach to fertility regulation for the majority of women who have regular intercourse and wish to limit the number of their pregnancies.

Stimulation of the growth and respiration of a methylotrophic bacterium by morphine

The growth of a pseudomonad on methanol was stimulated by the presence of morphine (or codeine) in the medium. The drug appeared to influence the amount of growth rather than its rate. Respiration of resting cells on a variety of substrates was stimulated by adding morphine. This report appears to be the first case of a microorganism whose growth and respiration is stimulated by an opiate.