Fluorescent-guided surgery and the use of indocyanine green sentinel lymph node mapping in the pediatric and young adult oncology population

BACKGROUND

Technetium-99 (99m Tc) lymphoscintigraphy with blue dye injection is an accepted method for sentinel lymph node (SLN) mapping, but blue dye has known adverse effects, and injection of 99m Tc may increase time under anesthesia for pediatric patients. Indocyanine green (ICG) may serve as an adjunct to assist with visibility and identification of SLNs. We hypothesized that sensitivity of ICG was similar to blue dye in SLN biopsies.

METHODS

Thirty patients (36 procedures with 96 total specimens) underwent preoperative intradermal injection of 99m Tc, followed by intradermal injection of isosulfan blue and ICG. Test characteristics of blue dye, ICG, and 99m Tc included sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV).

RESULTS

ICG had a sensitivity of 87% and PPV of 83% for detection of 99m Tc-hot lymph nodes; blue dye had a sensitivity of 44% and PPV of 97%. For detection of pathologically confirmed lymph nodes, ICG had a sensitivity of 84% and a positive predictive value (PPV) of 91%. 99m Tc had a sensitivity of 82% and a PPV of 94%. ICG had no significant difference in odds of being positive in pathology-confirmed lymph nodes compared to 99m Tc (odds ratio [OR], 0.818; 95% confidence interval [CI], 0.3-2.172; p = .823) and had higher odds than isosulfan blue (OR, 0.025, 95% CI, 0.001-0.148; p < .001).

CONCLUSION

This study established the efficacy of ICG as an adjunct to SLNB in the pediatric and young adult population. ICG was safe, more efficacious than blue dye, and may obviate the need for lymphoscintigraphy in selected patients resulting in reduced time under anesthesia.

Incidence and Management of Pleural Effusions in Patients with Wilms Tumor: A Pediatric Surgical Oncology Research Collaborative Study

Wilms tumor (WT) is the most common renal malignancy in children. Children with favorable histology WT achieve survival rates of over 90%. Twelve percent of patients present with metastatic disease, most commonly to the lungs. The presence of a pleural effusion at the time of diagnosis of WT may be noted on staging imaging; however, minimal data exist regarding the significance and prognostic importance of this finding. The objectives of this study are to identify the incidence of pleural effusions in patients with WT, and to determine the potential impact on oncologic outcomes. A multi-institutional retrospective review was performed from January 2009 to December 2019, including children with WT and a pleural effusion on diagnostic imaging treated at Pediatric Surgical Oncology Research Collaborative (PSORC) participating institutions. Of 1,259 children with a new WT diagnosis, 94 (7.5%) had a pleural effusion. Patients with a pleural effusion were older than those without (median 4.3 vs 3.5 years; p=0.004), and advanced stages were more common (local stage III 85.9% vs 51.9%; p<0.0001). Only 14 patients underwent a thoracentesis for fluid evaluation; 3 had cytopathologic evidence of malignant cells. Event-free and overall survival of all children with WT and pleural effusions was 86.2% and 91.5%, respectively. The rate and significance of malignant cells present in pleural fluid is unknown due to low incidence of cytopathologic analysis in our cohort; therefore, the presence of an effusion does not appear to necessitate a change in therapy. Excellent survival can be expected with current stage-specific treatment regimens.

Interhospital variability in localization techniques for small pulmonary nodules in children: A pediatric surgical oncology research collaborative study

BACKGROUND

Pulmonary nodules that are deep within lung parenchyma and/or small in size can be challenging to localize for biopsy. This study describes current trends in performance of image-guided localization techniques for pulmonary nodules in pediatric patients.

METHODS

A retrospective review was performed on patients < 21 years of age undergoing localization of pulmonary nodules at 15 institutions. Localization and resection success, time in interventional radiology (IR), operating room (OR) and total anesthesia time, complications, and technical problems were compared between techniques.

RESULTS

225 patients were included with an average of 1.3 lesions (range 1-5). Median nodule size and depth were 4 mm (range 0-30) and 5.4 mm (0-61), respectively. The most common localization techniques were: wire + methylene blue dye (MBD) (28%), MBD only (25%), wire only (14%), technetium-99 only (11%), coil + MBD (7%) and coil only (5%). Localization technique was associated with institution (p < 0.01); technique and institution were significantly associated with mean IR, OR, and anesthesia time (all p < 0.05). Comparing techniques, there was no difference in successful IR localization (range 92-100%, p = 0.75), successful resection (94-100%, p = 0.98), IR technical problems (p = 0.22), or operative complications (p = 0.16).

CONCLUSIONS

Many IR localization techniques for small pulmonary nodules in children can be successful, but there is wide variability in application by institution and in procedure time.

LEVEL OF EVIDENCE

Retrospective review, Level 3.

HDAC1-Dependent Repression of Markers of Hepatocytes and P21 Is Involved in Development of Pediatric Liver Cancer

BACKGROUND & AIMS

Epigenetic regulation of gene expression plays a critical role in the development of liver cancer; however, the molecular mechanisms of epigenetic-driven liver cancers are not well understood. The aims of this study were to examine molecular mechanisms that cause the dedifferentiation of hepatocytes into cancer cells in aggressive hepatoblastoma and test if the inhibition of these mechanisms inhibits tumor growth.

METHODS

We have analyzed CCAAT/Enhancer Binding Protein alpha (C/EBPα), Transcription factor Sp5, and histone deacetylase (HDAC)1 pathways from a large biobank of fresh hepatoblastoma (HBL) samples using high-pressure liquid chromatography-based examination of protein-protein complexes and have examined chromatin remodeling on the promoters of markers of hepatocytes and p21. The HDAC1 activity was inhibited in patient-derived xenograft models of HBL and in cultured hepatoblastoma cells and expression of HDAC1-dependent markers of hepatocytes was examined.

RESULTS

Analyses of a biobank showed that a significant portion of HBL patients have increased levels of an oncogenic de-phosphorylated-S190-C/EBPα, Sp5, and HDAC1 compared with amounts of these proteins in adjacent regions. We found that the oncogenic de-phosphorylated-S190-C/EBPα is created in aggressive HBL by protein phosphatase 2A, which is increased within the nucleus and dephosphorylates C/EBPα at Ser190. C/EBPα-HDAC1 and Sp5-HDAC1 complexes are abundant in hepatocytes, which dedifferentiate into cancer cells. Studies in HBL cells have shown that C/EBPα-HDAC1 and Sp5-HDAC1 complexes reduce markers of hepatocytes and p21 via repression of their promoters. Pharmacologic inhibition of C/EBPα-HDAC1 and Sp5-HDAC1 complexes by Suberoylanilide hydroxamic acid (SAHA) and small interfering RNA-mediated inhibition of HDAC1 increase expression of hepatocyte markers, p21, and inhibit proliferation of cancer cells.

CONCLUSIONS

HDAC1-mediated repression of markers of hepatocytes is an essential step for the development of HBL, providing background for generation of therapies for aggressive HBL by targeting HDAC1 activities.

Total pancreatectomy with islet autotransplantation reduces resource utilization in pediatric patients

BACKGROUND

Chronic pancreatitis (CP) is associated with poor quality of life. Total pancreatectomy with islet autotransplantation (TPIAT) has traditionally been reserved for patients with refractory disease. We hypothesized TPIAT would lead to decreased costs and resource utilization after operation in children.

METHODS

Retrospective review of 39 patients who underwent TPIAT at a single children's hospital was performed. All inpatient admissions, imaging, endoscopic procedures, and operations were recorded for the year prior to and following operation. Costs were determined from Centers for Medicare and Medicaid Services.

RESULTS

Median hospital admissions before operation was 5 (IQR:2-7) and decreased to 2 (IQR:1-3) after (p < 0.01). Median total cost for the year before operation was $36,006 (IQR:$19,914-$47,680), decreasing to $24,900 postoperatively (IQR:$17,432-$44,005, p = 0.03). Removing cost of TPIAT itself, total cost was further reduced to $10,564 (IQR:$3096-$29,669, p < 0.01).

CONCLUSION

In children with debilitating CP, TPIAT has favorable impact on cost reduction, hospitalizations, and invasive procedures. Early intervention at a specialized pancreas center of excellence should be considered to decrease future resource utilization and costs among children.

Lack of National Adoption of Evidence-Based Treatment for Resectable Gastric Adenocarcinoma

BACKGROUND

Level 1 evidence for multimodal treatment of resectable gastric adenocarcinoma from the Intergroup 0116 (2001) and MAGIC (2006) trials demonstrated survival benefit of adjuvant chemoradiation (CRT) and perioperative chemotherapy, respectively. We evaluated the adoption of evidence-based treatment in the post-MAGIC era and its impact on survival.

METHODS

A total of 7058 patients with resectable gastric adenocarcinoma undergoing definitive surgical resection between 2004 and 2015 were analyzed using the National Cancer Database.

RESULTS

Over the study period, the proportion of patients receiving adjuvant CRT decreased from 19.1% to 9.1%, while perioperative chemotherapy increased from 1.9% to 28.6%. Utilization of perioperative chemotherapy surpassed adjuvant CRT in 2011. Evidence-based treatment (either perioperative chemotherapy or adjuvant CRT) had better overall survival (OS) than other treatments for clinical stage II-III patients (p < 0.05). On multivariate analysis of the whole study period, evidence-based treatments were associated with better OS (HR 0.67 [0.60-0.74], p < 0.05). Only 360/1262 (28.5%) patients in the perioperative chemotherapy group completed postoperative therapy, which was associated with improved OS (p < 0.05). For clinical stage III patients (n = 2402), only 806 (33.6%) received evidence-based treatment, while 487 (22.2%) underwent surgery alone. On multivariate analysis of these patients between 2010 and 2015, both perioperative chemotherapy (HR 0.49 [0.35-0.68]) and adjuvant CRT (HR 0.31 [0.21-0.44]) were associated with better OS than surgery alone (p < 0.05).

CONCLUSIONS

Since the INT-0116 and MAGIC trials, utilization of evidence-based treatments for resectable gastric adenocarcinoma has increased, with perioperative chemotherapy surpassing adjuvant CRT as the preferred practice. However, overall utilization of these regimens remains quite low nationally despite association with improved OS.

Molecular signatures of aggressive pediatric liver cancer

Liver masses account for 5 to 6% of pediatric cancer, which includes hepatoblastoma (HBL) along with rare cases of hepatocellular carcinoma (HCC). The most dangerous form of pediatric liver cancer is aggressive HBL, which can be characterized by chemo-resistance and multiple nodules or metastases at diagnosis, all correlating with worse clinical prognosis. Despite intensive studies and a significant improvement in overall outcomes, very little is known about the key molecular pathways which determine the aggressiveness of pediatric liver cancer. Although genetic mutations have been reported in aggressive HBL, they represent a low level (1.9% per case) and are found mainly in two genes CTNNB1 and NRF2. Over the past 5 years, our liver biology and tumor group at Cincinnati Children's Hospital Medical Center has investigated molecular signatures of aggressive HBL by examination of fresh tissue specimens, which were studied immediately after surgery to preserve the integrity of key biochemical pathways. Summarization of these high quality HBL samples discovered several critical pathways that are specific for aggressive pediatric liver cancer. These pathways include three characteristics: Conversion of tumor suppressor proteins (TSPs) by posttranslational modifications into oncogenesActivation of specific chromosomal regions, i.e., Aggressive Liver Cancer Domains (ALCDs) within many oncogenes, resulting in increased expression of oncogenesPotential epigenetic mechanisms that open chromatin structure of oncogenes via ALCDs. This commentary summarizes our key findings and discusses development of potential ALCD-based therapeutic approaches.

PSII-18 Dietary Strategy for Gilt Development

The objective was to determine a dietary strategy for gilt development that would improve reproductive performance. One thousand eighty-three gilts (DNA) were blocked by weight (average initial weight = 27.5 ± 4.8 kg) and allocated to one of four dietary treatments (267-273 gilts per treatment). Treatments included: 1) standard grower/finisher (SGF) diet; 2) maximize bone growth (MB) diet with increased available P and Ca; 3) maximize growth (MG) diet with increased energy and AA levels, or 4) maximize both bone and growth (MBG) diet. Each treatment had five phases with all gilts fed a common gestation diet after insemination. At 20 weeks of age, gilts fed MG and MBG diets were heavier (P &lt; 0.05) than gilts fed other diets. Gilts fed the MG diet were heavier (116.9 kg; P &lt; 0.05) at 23 weeks (start of boar exposure) than gilts fed other diets (SGF, 112 kg; MB, 110.3 kg; MBG, 114.6 kg). Gilts fed the MG diet were heavier (143.8 kg; P &lt; 0.05) at mating (29 weeks of age) than gilts fed other diets (SGF, 139.0 kg; MB, 136.8 kg; MBG, 139.6 kg). Upon entering farrowing stalls, gilts fed the MG diet continued to be heavier (P &lt; 0.05). More gilts farrowed (P &lt; 0.05) when fed the MG diet (MG, 89.8%; MBG, 86.8%; MB, 82.2%; SGF, 81.9%). Dietary treatment had no impact on number of pigs born alive per litter, total pigs born per litter, or piglet birth and weaning weights. There was a tendency (P &lt; 0.10) for gilts to remain in the sow herd to farrow their second litter when fed either the MG or MBG diet. Overall, feeding higher energy and AA levels to maximize growth increased gilt development weights, improved the number of gilts that farrowed, and tended to increase sow retention.

273 Impact of either high energy or high SID Lys:ME on Parity 1 performance in lactation

Primiparous sows may have difficulty consuming sufficient feed during lactation to account for energy lost in milk production, development, and body maintenance. Addition of higher energy and/or higher standardized ileal digestible (SID) Lys may improve gilt and litter performance. One hundred seventy-two primiparous DNA F1 females were randomly allotted within breeding/farrowing group, previous treatment, and entry weight at farrowing to one of four dietary treatments. Treatments were arranged in a 2 x 2 factorial with energy (3186 and 3332 kcal/kg ME) and SID lysine (1.15 and 1.30%). Sows were weighed upon entry and exit of the farrowing room. Feed disappearance was calculated as the total amount of feed provided to the sow during lactation. A post-farrow weight model was utilized to assess true weight loss in lactation. Litters were standardized within 24 h of birth, and individual pig birth and weaning weights were recorded. The wean to estrus interval was also measured. Data were analyzed as a randomized complete block design with the fixed effect of treatment and the random effect of replicate. Addition of high energy and/or high lysine did not impact (P &gt; 0.10) piglet wean weight or sow average daily feed intake. High energy diets reduced (P &lt; 0.05) sow weight loss post-farrow by 15.5% from 8.75 to 7.39 kg. High SID lysine diets reduced (P &lt; 0.05) number of sows not expressing estrus by day 9 post-wean from 13.0 to 7.7% of sows eligible for insemination. The high SID lysine diets targeted 70 g/d and led to an increase (P &lt; 0.05) of 10.3% of sows displaying estrus on day 4 and 5. These data show that higher levels of SID lysine to target 70 g/d in lactation can improve wean to estrus interval, and potentially decrease non-productive sow days.

Natural Course of Pediatric Portal Hypertension

The etiology of portal hypertension (pHTN) in children differs from that of adults and may require different management strategies. We set out to review the etiology, management, and natural history of pHTN at a pediatric liver center. From 2008 to 2018, 151 children and adolescents with pHTN were identified at a free‐standing children’s hospital. Patients were stratified by etiology of pHTN (intrahepatic disease [IH], defined as cholestatic disease and fibrotic or hepatocellular disease; extrahepatic disease [EH], defined as hepatic vein obstruction and prehepatic pHTN). Patients with EH were more likely to undergo an esophagoduodenscopy for a suspected gastrointestinal bleed (77% vs. 41%; P < 0.01). Surgical interventions differed based on etiology (P < 0.01), with IH more likely resulting in a transplant only (65%) and EH more likely to result in a shunt only (43%); 30% of patients with IH and 47% of patients with EH did not undergo an intervention for pHTN. Kaplan‐Meier analysis revealed a significant increase in mortality in the group that received no intervention compared to shunt, transplant, or both and lower mortality in patients with prehepatic pHTN compared to other etiologies (P < 0.01 each). Multivariate analysis revealed increased odds of mortality in patients with refractory ascites (odds ratio [OR], 4.34; 95% confidence interval [CI], 1.00, 18.88; P = 0.05) and growth failure (OR, 13.49; 95% CI, 3.07, 58.99; P < 0.01). Conclusion: In this single institution study, patients with prehepatic pHTN had better survival and those who received no intervention had higher mortality than those who received an intervention. Early referral to specialized centers with experience managing these complex disease processes may allow for improved risk stratification and early intervention to improve outcomes.

National Trend of Axillary Management in Clinical T3/T4 N0 Patients Having Breast Conserving Therapy

BACKGROUND

The ACOSOG Z0011 trial has essentially eliminated axillary lymph node dissection (ALND) in breast conserving therapy (BCT) patients with clinical T1/T2 and 1-2 positive sentinel lymph nodes (SLNs). Currently, ALND is recommended for positive SLNs unless ACOSOG Z0011 criteria are applicable. We aimed to assess the national trends and axillary management before and after the publication of ACOSOG Z0011 for larger tumors.

METHODS

An IRB-approved study evaluated the National Cancer Database from 2006 to 2016. Women with clinical T3/T4, N0 who otherwise fit ACOSOG Z0011 criteria were included. Neoadjuvant systemic therapy or known nodal disease was excluded. Clinicopathologic data were compared between two timeframes based on ACOSOZ Z0011 publication and by axillary management. Patients were categorized into SLNB alone (1-5 lymph nodes examined) and ALND (≥10 lymph nodes examined) groups.

RESULTS

A total of 230 women fit inclusion criteria, of whom 36% underwent ALND. ALND use decreased from 54% in 2006 to 14% in 2016 (P < 0.01). Comparing ALND to SLNB alone within the pre-Z0011 era, comprehensive community cancer programs had higher proportions of ALND, whereas academic centers had higher rates of SLND alone (P = 0.03). Comparing similar axillary management between eras, SLNB-alone patients in the post-Z0011 era had higher pT and pN stages, were less likely to be Her2 positive, and were more likely to receive systemic treatment.

CONCLUSIONS

There is a national trend to forgo ALND in women who have tumors larger than those included in the Z0011 criteria without any clear clinicopathologic indications.

Surgical management of primary pancreatic neuroendocrine tumors

Pancreatic neuroendocrine tumors (PanNETs) are the second most common malignancy of the pancreas, and their incidence is increasing. PanNETs are a diverse group of diseases which range from benign to malignant, can be sporadic or associated with genetic mutations, and be functional or nonfunctional. In as much, the treatment and management of PanNETs can vary from a "Wait and See" approach to orthotopic liver transplantation (OLT). Despite this, surgical resection is still the primary treatment modality to achieve cure. This review focuses on the surgical management of PanNETs.

Effect of numbers of sperm and timing of a single, post-cervical insemination on the fertility of weaned sows treated with OvuGel®

Variability in estrus and ovulation requires multiple inseminations during estrus to ensure one AI occurs close to ovulation. Induction of ovulation after weaning improves synchrony of ovulation and allows for fixed time AI. However, the interaction between number of sperm in the AI dose and the timing of insemination has not been fully investigated. The objective of this study was to determine the effects of sperm numbers used in a single post-cervical insemination (PCAI) and the timing of insemination following induced ovulation in weaned sows. The experiment was performed using sows (n = 641) allotted by parity (1-6) and lactation length (19.5 d) to receive a single PCAI using 1.5 or 2.5 billion motile sperm at either 22, 26, or 30 h following administration of a GnRH agonist, triptorelin acetate (OvuGel^®) at 96 h post-weaning. Sows received boar contact once daily 3-6 d following weaning. A sub-population of the sows (n = 499) were assessed for follicle size and ovulation utilizing ultrasound at 8 h intervals. There was no interaction of number of sperm and timing of insemination for any response measure (P > 0.10). Wean to estrus interval (4.8 d), duration of estrus (1.9 d), and expression of estrus (88.0%), were not different among treatments (P > 0.10). Of sows scanned by ultrasound at the time of OvuGel^®, 88.2% had large follicles, 10.9% had small, medium or cystic sized follicles, and 0.9% had corpora lutea. The proportion of sows that ovulated averaged 94%, and differed by time of AI (P ≤ 0.05) but not by number of sperm. Pregnancy rate and farrowing rate tended to be affected by dose (P ≤ 0.10), while time of insemination affected pregnancy rate and tended to influence farrowing rate (P ≤ 0.10). Farrowing rate was greater (P < 0.0001) with use of 2.5 than 1.5 billion sperm and insemination at 22 and 26 h compared to 30 h after OvuGel^® (P ≤ 0.10). Farrowing rate was also affected by parity, estrus expression, ovulation and ovarian abnormalities (P < 0.05). Of the 12% of weaned sows that did not exhibit estrus, approximately 50% farrowed a litter. Total born and born alive were affected by dose (P < 0.05) but not time of insemination with both measures increased with 2.5 compared to 1.5 billion sperm (P < 0.05). The results of this study indicate that induction of ovulation in weaned sows resulted in 88% of sows ovulating within a 24 h period. Fertility was improved with a single, fixed time AI using 2.5 compared to 1.5 billion motile sperm and insemination at 22-26 h after OvuGel^® compared to 30 h.

Prophylactic feeding tubes for patients with locally advanced head-and-neck cancer undergoing combined chemotherapy and radiotherapy-systematic review and recommendations for clinical practice

GOALS

This work aimed to determine the benefits and risks of prophylactic feeding tubes for adult patients with squamous cell carcinoma of the head and neck who receive combined chemotherapy and radiotherapy with curative intent and to make recommendations on the use of prophylactic feeding tubes and the provision of adequate nutrition to this patient population.

METHODS

A national multidisciplinary panel conducted a systematic review of the evidence and formulated recommendations to guide clinical decision-making. The draft evidence summary and recommendations were distributed to clinicians across Canada for their input.

MAIN RESULTS

No randomized controlled trials have directly addressed this question. Evidence from studies in the target population was limited to seven descriptive studies: two with control groups (one prospective, one retrospective) and five without control groups. Results from ten controlled studies in patients treated with radiotherapy alone were also reviewed.

CONCLUSIONS

The available evidence was insufficient to draw definitive conclusions about the effectiveness of prophylactic feeding tubes in the target patient population or to support an evidence-based practice guideline. After review of the evidence, of guidelines from other groups, and of current clinical practice in Canada, the multidisciplinary panel made consensus-based recommendations regarding comprehensive interdisciplinary clinical care before, during, and after cancer treatment. The recommendations are based on the expert opinion of the panel members and on their understanding of best clinical practice.

Impact of lactation length and piglet weaning weight on long-term growth and viability of progeny

A total of 1,034 pigs produced by breeding PIC sows to 2 different PIC terminal sires were used to create 3 distinct weaning weight populations so that postweaning growth to 125 kg could be studied. The rearing strategies resulted in BW that ranged from 4.1 to 11.5 kg by 20 d of age. Sows and corresponding litters were allocated to 3 treatments: sow reared (SR; n = 367) for 20 d, sow reared for 14 d (14W; n = 330), and sow reared for 2 d (2W; n = 337). Sows were removed from 2W and 14W groups, but progeny remained in the crates and received milk replacer ad libitum (for 18 and 6 d, respectively) until the contemporary SR pigs were weaned at 20 d of age. The SR pigs (6.49 +/- 0.15 kg) weighed 1.01 kg less than 14W pigs (7.5 +/- 0.14 kg) and 2.26 kg less than 2W pigs (8.75 +/- 0.14 kg; P < 0.05). The 14W pigs weighed 1.25 kg less than 2W pigs (P < 0.05). Nursery ADG for the 2W group (547 g/d) was 35 g/d less (P < 0.05) than 14W pigs. The 14W pigs (165 d) required 3 fewer (P < 0.05) days to reach 125 kg of BW compared with SR pigs. The SR and 14W pigs gained BW 24 and 20 g/d faster (P < 0.05) in the postnursery period when compared with 2W pigs. The SR and 2W pigs consumed 0.10 and 0.12 kg/d less (P < 0.05) during this period when compared with 14W pigs (2.32 kg/d). Gain:feed of SR was improved (P < 0.05) when compared with the 14W and 2W pigs over 167 d of age (0.44 vs. 0.42 and 0.42, respectively). Lean percentage was 0.7% greater (P < 0.05) in carcasses from SR pigs (55.0%) compared with carcasses from 2W pigs (54.3%) when adjusted to a constant HCW. A study of the effect of weaning weight on days to 125 kg was limited to SR and 14W groups because maternal deprivation compromised the 2W group postweaning growth. Six weaning-weight groups were defined using a normal distribution: 4.6, 5.5, 6.4, 7.3, 8.2, and 9.5 kg. Pigs weighing 5.5 kg at 20 d of age were able to reach 125 kg 8 d sooner (168.8 d) than those weighing 4.6 kg (176.8 d). There was a linear relationship (P < 0.05) between weaning weight and ADG in the postnursery phase of growth. We conclude that 1) a weaning weight of less than 5.0 kg imposes the greatest marginal loss in production output for a 20-d weaning and 2) lactation length influences long-term growth, composition of growth, and viability of progeny.

The dietary valine requirement for prolific lactating sows does not exceed the National Research Council estimate

Two studies were conducted to determine the effect of increasing the valine:lysine (V:L) ratio in diets of lactating sows above the minimum proposed by the NRC (1998). The first experiment involved 189 PIC, Camborough product sows (parity 1 to 4) that were allotted to 1 of 3 dietary treatments. Diets were formulated to achieve total dietary V:L ratios of 0.90, 1.05, or 1.25:1, respectively, and were corn and soybean meal-based. The second experiment involved 279 PIC, Camborough sows (parity 1 to 5) that were allotted to 1 of 4 treatments. Diets 1 and 3 were formulated using corn and a fixed inclusion of soybean meal (16.7%), with 0.27% L-lysine HCl. The V:L ratios in diets 1 and 3 were 0.73 and 1.25:1, respectively. Diets 2 and 4 were typical corn-soybean meal diets containing 0.05% L-lysine HCl, with a fixed inclusion of soybean meal (22.7%). The V:L ratios in diets 2 and 4 were 0.86 and 1.25:1, respectively. In both experiments, each litter was standardized to a minimum of 10 pigs, which achieved litter growth rates of 2.22 and 2.56 kg/d in Exp. 1 and 2, respectively. In Exp. 1, increasing the dietary V:L ratio beyond 0.90:1 did not improve (P > 0.10) the number of pigs weaned, survival rate, or piglet growth rate, even though sows were nursing more than 10 pigs per litter for 19 d. In Exp. 2, total lysine intake was similar among treatments and ranged from 52.1 to 55.3 g/d. Valine intake increased as the diet valine concentration increased (diet 1 vs. 3 and diet 2 vs. 4, P < 0.001), ranging from 40.0 to 66.1 g/d. Litter gain tended to improve (P = 0.14) when the 0.27% L-lysine HCl control (0.73 V:L) was supplemented with valine to achieve a 1.25:1 V:L ratio. In contrast, no aspect of sow or litter response was improved when the practical control diet containing 0.05% L-lysine HCl (0.86 V:L) was supplemented with valine to achieve a 1.25:1 V:L ratio. Collectively, this research shows that a V:L ratio in excess of 0.86 does not conserve maternal tissue loss or improve piglet growth rate, but a V:L ratio of 0.73 may compromise litter growth rate.

Phosphorus requirements of growing-finishing pigs reared in a commercial environment

The objective of this study was to identify available phosphorus (aP) requirements of pigs reared in commercial facilities. In a preliminary study, 600 gilts (PIC) were allotted randomly to low (0.30%) or high (0.37%) dietary aP from 43 to 48 kg BW, and later to 0.19 or 0.27% aP from 111 to 121 kg BW. No differences were observed (P = 0.42 to 0.88) in ADG, but G:F from 43 to 48 kg tended to improve (P = 0.07) for pigs fed low aP. Results suggested that the aP requirement was at or below 0.30 and 0.19%. These concentrations were used to titrate aP requirements in Exp. 1 and 2. In Exp. 1, 1,260 gilts (initially 33.8 kg) were allotted randomly to one of five dietary treatments containing 0.18, 0.22, 0.25, 0.29, or 0.32% aP, corresponding to 0.5, 0.6, 0.7, 0.8, or 0.9 g of aP/Mcal of ME. There were 28 pigs per pen and nine pens per treatment. From d 0 to 14, increasing aP increased ADG (linear, P = 0.03) and G:F (quadratic, P = 0.07), with the greatest response observed as aP increased from 0.18 to 0.22% (G:F breakpoint = 0.22%). However, from d 0 to 26, no differences (P = 0.12 to 0.81) were observed for any growth traits. Pooled bending moment of the femur, sixth rib, and third and fourth metatarsals increased (linear, P = 0.007) with increasing aP. In Exp. 2, 1,239 gilts (initially 88.5 kg BW) were randomly allotted to one of five dietary treatments containing 0.05, 0.10, 0.14, 0.19, or 0.23% aP, equivalent to 0.14, 0.28, 0.39, 0.53, or 0.64 g of aP/Mcal of ME. The diet with 0.05% aP contained no added inorganic P. From d 0 to 14, increasing aP increased (linear, P = 0.008 to 0.02) ADG and G:F; however, from d 0 to 28, increasing aP had no effect (P = 0.17 to 0.74) on growth performance. Increasing aP increased (linear, P < 0.001 to 0.04) metacarpal bone ash percent and bending moment. Results suggest that 33- to 55-kg pigs require approximately 0.22% aP, which corresponds to 0.60 g of aP/Mcal of ME or 3.30 g of aP/d to maximize ADG and G:F compared with NRC (1998) estimates of 0.23%, 0.70 g of aP/Mcal of ME, and 4.27 g of aP/d for 20- to 50-kg pigs. Finishing pigs (88 to 109 kg) require at least 0.19% aP, corresponding to 0.53 g of aP/Mcal of ME or 4.07 g aP/d compared with NRC (1998) estimates of 0.15%, 0.46 g of aP/Mcal of ME and 4.61 g of aP/d for 80- to 120-kg pigs. However, the percentage of bone ash and bending moment continued to increase with increasing aP. These data also suggest that complete removal of supplemental P in diets for finishing pigs (>88 kg) will decrease ADG and G:F.

Chemotherapy for recurrent epithelial ovarian cancer previously treated with platinum--a systematic review of the evidence from randomized trials

PURPOSE

To evaluate the chemotherapeutic options for women with recurrent epithelial ovarian cancer who have received platinum-based chemotherapy.

METHODS

A systematic search of the Medline, CancerLit and Cochrane Library databases was performed for the period from 1984 to June 2001 to find randomized trials comparing second- or higher-line chemotherapy regimens in patients with recurrent platinum-pretreated epithelial ovarian cancer.

RESULTS

Seven randomized trials have failed to demonstrate the clear superiority of any one chemotherapy regimen in terms of improvements in long-term survival, quality of life or response rate. One trial detected a statistically significant difference between treatments in progression-free survival, which was longer with cyclophosphamide/doxorubicin/cisplatin than with paclitaxel in women with platinum-sensitive ovarian cancer. Another trial did not show a difference between liposomal doxorubicin and topotecan overall in women with recurrent ovarian cancer but a subgroup analysis detected a significant survival advantage for liposomal doxorubicin over topotecan in women with platinum-sensitive disease.

CONCLUSION

The evidence available does not support firm conclusions about the preferred chemotherapy regimen for recurrent ovarian cancer. Randomized trials that compare new drugs with current standard treatments are needed.

Effects of computer-based clinical decision support systems on clinician performance and patient outcome. A critical appraisal of research

OBJECTIVE

To review the evidence from controlled trials of the effects of computer-based clinical decision support systems (CDSSs) on clinician performance and patient outcomes.

DATA SOURCES

The literature in the MEDLARS, EMBASE, SCISEARCH, and INSPEC databases was searched from 1974 to the present. Conference proceedings and reference lists of relevant articles were reviewed. Evaluators of CDSSs were asked to identify additional studies.

STUDY SELECTION

793 citations were examined, and 28 controlled trials that met predefined criteria were reviewed in detail.

DATA EXTRACTION

Study quality was assessed, and data on setting, clinicians and patients, method of allocation, computer system, and outcomes were abstracted and verified using a structured form. Separate summaries were prepared for physician and patient outcomes. Within each of these categories, studies were classified further according to the primary purpose of the CDSS: drug dose determination, diagnosis, or quality assurance.

RESULTS

Three of 4 studies of computer-assisted dosing, 1 of 5 studies of computer-aided diagnosis, 4 of 6 studies of preventive care reminder systems, and 7 of 9 studies of computer-aided quality assurance for active medical care that assessed clinician performance showed improvements in clinician performance using a CDSS. Three of 10 studies that assessed patient outcomes reported significant improvements.

CONCLUSIONS

Strong evidence suggests that some CDSSs can improve physician performance. Additional well-designed studies are needed to assess their effects and cost-effectiveness, especially on patient outcomes.

Performances of 27 MEDLINE systems tested by searches with clinical questions

OBJECTIVE

To compare the performances of online and compact-disc (CD-ROM) versions of the National Library of Medicine's (NLM) MEDLINE database.

DESIGN

Analytic survey.

INTERVENTION

Clinical questions were drawn from 18 searches originally conducted spontaneously by clinicians from wards and clinics who had used Grateful Med Version 4.0. Clinicians' search strategies were translated to meet the specific requirements of 13 online and 14 CD-ROM MEDLINE systems. A senior librarian and vendors' representatives constructed independent searches from the clinicians' questions. The librarian and clinician searches were run through each system, in command mode for the librarian and menu mode for clinicians, when available. Vendor searches were run through the vendors' own systems only.

MAIN MEASUREMENTS

Numbers of relevant and irrelevant citations retrieved, cost (for online systems only), and time.

RESULTS

Systems varied substantially for all searches, and for librarian and clinician searches separately, with respect to the numbers of relevant and irrelevant citations retrieved (p < 0.001 for both) and the cost per relevant citation (p = 0.012), but not with respect to the time per search. Based on combined rankings for the highest number of relevant and the lowest number of irrelevant citations retrieved, the SilverPlatter CD-ROM MEDLINE clinical journal subset performed best for librarian searches, while the PaperChase online system worked best for clinician searches. For cost per relevant citation retrieved, Dialog's Knowledge Index performed best for both librarian and clinician searches.

CONCLUSIONS

There were substantial differences in the performances of competing MEDLINE systems, and performance was affected by search strategy, which was conceived by a librarian or by clinicians.

The effects of porcine somatotropin and dietary lysine on growth performance and carcass characteristics of finishing swine fed to 105 or 127 kilograms

One hundred twenty barrows (initially 59 kg) were used to determine the effects of dietary lysine and porcine somatotropin (pST) on growth performance and carcass characteristics of finishing pigs fed to heavy market weights (127 kg). Pigs were injected daily with either 4 mg of pST or a placebo and fed diets containing either .8, 1.0, 1.2, or 1.4% lysine in a 2 x 4 factorial arrangement. Performance data were collected and evaluated for the weight ranges: 59 to 105, 105 to 127, and 59 to 127 kg. In addition, daily accretion rates of protein (DPA), lipid (DLA), moisture, and ash were determined by slaughtering six randomly selected pigs at the start of the experiment, then one pig per pen when pigs reached mean weights of 105 and 127 kg. Pigs injected with pST had greater (P < .05) ADG than control pigs at all weight ranges. Increased dietary lysine had no effect (P > .20) on ADG during the entire trial (59 to 127 kg). Although control pigs showed no increase in ADG with increasing lysine, ADG of pST-treated pigs tended to increase. This resulted in a pST x lysine interaction (P < .07) for ADG from 59 to 127 kg. Feed consumption decreased (P < .05) in pigs from 59 to 105 kg and 59 to 127 kg with pST treatment and with increasing dietary lysine. Feed conversion (G/F) was improved (P < .01) by pST administration and a tendency for a pST x lysine interaction (P < .12) was observed. At 105 kg, average backfat thickness, kidney fat, longissimus muscle area, and DPA were unaffected by dietary lysine but were improved by pST treatment (P < .01). At a slaughter weight of 127 kg, average backfat thickness decreased and DPA increased (linear, P < .05) with increasing dietary lysine and pST treatment (P < .01). Longissimus muscle area was increased and DLA was decreased (P < .01) by injections of pST but both were unchanged by dietary lysine. These data indicate that growth performance and carcass characteristics at 105 and 127 kg were improved by daily administration of 4 mg of pST. At both slaughter weights, increasing dietary lysine resulted in increased carcass leanness (increased carcass protein and decreased carcass lipid). Although increasing lysine did not improve overall (59 to 127 kg) ADG and feed efficiency, pST-treated pigs showed a greater response to increasing dietary lysine. The data indicate that pST-treated pigs (4 mg/d) require approximately 28 g/d of lysine.

A program to enhance clinical use of MEDLINE. A randomized controlled trial

OBJECTIVE

To determine if a preceptor and individualized feedback improves the performance of physicians in searching MEDLINE in clinical settings.

DESIGN

Randomized controlled trial with 2 to 10 months follow-up.

SETTING

A 300-bed teaching hospital.

PARTICIPANTS

All 392 physicians and physicians-in-training from 6 major clinical departments were invited to participate if they made patient-care decisions during the study period; 79.4% agreed.

INTERVENTIONS

All participants were given 2 hours of basic training, then randomized to a control group (no further intervention) or an intervention group in which each person chose a clinical preceptor experienced in MEDLINE searching and received individualized feedback from a study librarian on each of their 1st 10 searches.

MAIN OUTCOME MEASURES

The number and proportion of relevant and irrelevant references retrieved for 1st, 4th, and 8th searches of participants were compared with independent librarian searches on the same topics.

RESULTS

Intervention group members did not search more often than controls (5.9 searches per month versus 4.7, respectively; P = 0.26) and there were no significant differences in the quality of searches. Rather, search performance for both groups improved, with the average number of relevant references retrieved per search increasing from 4.5 to 7.4 (P < 0.01). The librarian retrieved more relevant citations than participants for the 1st search (P = 0.001) but not for the 4th (P = 0.60) or 8th (P = 0.76) searches.

CONCLUSIONS

A program of assigning preceptors and providing feedback on individual searches did not enhance the quantity or quality of searches. Soon after a basic introduction to searching, however, clinicians in both groups improved their search performance.

Effect of problem-based, self-directed undergraduate education on life-long learning

OBJECTIVE

To compare how well graduates of a self-directed, problem-based undergraduate curriculum (at McMaster University [MU], Hamilton, Ont.) and those of a traditional curriculum (at the University of Toronto [UT]) who go on to primary care careers keep up to date with current clinical practice guidelines.

DESIGN

Analytic survey. Management of hypertension was chosen as an appropriate topic to assess guideline adherence. An updated version of a previously validated questionnaire was mailed to the participants for self-completion.

SETTING

Private primary care practices in southern Ontario.

PARTICIPANTS

A random sample of 48 MU graduates and 48 UT graduates, stratified for year of graduation (1974 to 1985) and sex, who were in family or general practice in Ontario; 87% of the eligible subjects in each group responded.

MAIN OUTCOME MEASURES

Overall and component-specific scores; analysis was blind to study group.

RESULTS

The overall mean scores were 56 (68%) of a possible 82 for the MU graduates and 51 (62%) for the UT graduates (difference between the means 5, 95% confidence interval 1.9 to 8.2; p < 0.01). Multivariate linear regression analysis of seven factors that might affect questionnaire scores revealed that only the medical school was statistically significant (p < 0.01). The MU graduates had significantly higher mean scores than the UT graduates for two components of the questionnaire: knowledge of recommended blood pressures for treatment (p < 0.05) and successful approaches to enhance compliance (p < 0.005). The trends were similar for the other components but but were not significant.

CONCLUSIONS

The graduates of a problem-based, self-directed undergraduate curriculum are more up to date in knowledge of the management of hypertension than graduates of a traditional curriculum.

Depression, problem-solving ability, and problem-solving appraisals

Behavioral analytic methods were used to create a college student version of the Means Ends Problem Solving Procedure (MEPS). This instrument then was administered with measures of perceived problem-solving ability to depressed and nondepressed students to determine whether differences exist in both problem-solving ability and problem-solving appraisal. Analyses revealed that depressed subjects had more negative expectations and lower appraisals of their problem-solving ability. However, the groups did not differ in terms of the actual quality of their behavioral solutions to interpersonal, intrapersonal, and emotional problem situations. The results are interpreted as support for the role of cognitive factors in depression and problem-solving across a range of problem-solving situations.

Increases in knowledge and use of information technology by entering medical students at McMaster University in successive annual surveys

OBJECTIVE

To determine self-reported microcomputer and information technology competency, access, and usage by entering medical students and their perceptions of the need for training in additional applications.

DESIGN

Cross-sectional surveys of successive classes.

SETTING

McMaster University Faculty of Health Sciences Medical Undergraduate Program, which has a 33-month, problem-based, self-directed learning curriculum and a high applicant-to-student ratio.

PARTICIPANTS

Medical school classes entering in 1987, 1988, and 1989. Response rates were 80%, 90%, and 86% respectively.

MEASURES

A self-report questionnaire was sent to each student, with up to two follow-up letters to prompt a response.

RESULTS

There was a progressive rise in reported information technology access and use for the three years. For the classes starting in 1987, '88, and '89 respectively, computer access was 29%, 49%, and 49% (P < 0.002 for linear trend), and, among those with computer access, modem access was 17%, 29% and 50% (P = 0.012). Self-service MEDLINE use on CD-ROM at the Health Sciences Library was 65%, 75%, and 89% respectively (P < 0.001) for all respondents within the first few months of starting medical school. Over 50% of each class stated they would take courses, if available, on clinical applications software, office management, online searching, filing, and CD-ROM searching.

CONCLUSIONS

Half of the most recent entering students already had access to a personal computer and most wished to learn computer applications that would assist them with patient management, and with information access and organization. Medical schools need to address which applications they will teach or make available and how to bring all students to acceptable competency in their use.

Performance appraisal of online MEDLINE access routes

OBJECTIVE

To compare the performance and cost of 11 online MEDLINE systems with MEDLINE at Elhill.

DESIGN

Comparative study. SYSTEMS: Eleven online daytime systems commercially available in North America offering the MEDLINE database.

MEASURES

Number of relevant citations, number of irrelevant citations, proportion of searches producing no relevant citations and cost per relevant citation were analyzed for each system. Relevance and cost for each system were compared with direct searching of MEDLINE through NLM for librarian and clinician search strategies for 18 clinical questions. The citations retrieved by both strategies were pooled and rated for relevance on a 7-point scale.

RESULTS

Numbers of relevant and irrelevant citations and cost per relevant citation were higher for clinician searches than librarian searches, reflecting the higher total number of citations retrieved by the clinician approaches. A lower proportion of clinician searches produced no relevant citations than librarian searches.

CONCLUSIONS

Eleven daytime MEDLINE systems performed similarly in terms of retrieval and cost within similar searching groups. Clinicians, however, tended to capture larger overall retrievals resulting in higher numbers of relevant and irrelevant citations than librarians.

A study to enhance clinical end-user MEDLINE search skills: design and baseline findings

OBJECTIVE

To determine if a preceptor and timely, individualized feedback improves the performance of physicians in searching MEDLINE using GRATEFUL MED in clinical settings.

DESIGN

Randomized controlled trial.

SETTING

A 300 bed primary to tertiary care teaching hospital. Computers were installed in wards and clinics of 6 major clinical services, and the emergency room, intensive care and neonatal intensive care units.

SUBJECTS

All physicians and physicians-in-training from the departments of Medicine, Family Medicine, Surgery, Psychiatry, Pediatrics, and Obstetrics and Gynecology were included if they made patient care decisions for at least 8 weeks during the study period.

INTERVENTION

All participants were given a 1-hour training class and 1 hour of individualized searching with 1 of the 2 study librarians. After training, participants were randomized to a control group who received no further intervention or to an intervention group in which each person chose a clinical preceptor experienced in MEDLINE searching and received individualized feedback by a study librarian on their first 10 searches, indicating search quality and providing suggestions for improvement. Feedback was mailed the first week day after the search was done.

MAIN MEASURES

Baseline characteristics by study group, department and level of training, study participation rates, and searching rates.

MAIN RESULTS

308 of 392 eligible physicians joined the study. Participation was almost 80% with some variation by department and level of training. Excellent balance in the baseline characteristics was achieved for the 2 groups, as well as for the number who did first searches. Intervention group participants searched MEDLINE more often than did controls (3.5 searches per month vs 2.5 per month for controls, P = 0.046). The recall and precision for first searches for both groups was significantly less than that of librarians. The analysis of study data will be completed by September 1991.

CONCLUSIONS

Clinicians are willing to do self-service searching of MEDLINE in clinical settings but their precision and recall are less than a trained librarian at baseline. Search skills enhancements are needed and the effect of feedback and preceptors is being tested.

SOURCE OF FUNDING

U.S. National Library of Medicine and Ontario Ministry of Health.

Effect of select menhaden fish meal in starter diets for pigs

Two trials were conducted to evaluate a select menhaden fish meal (SMFM) as a protein source in starter diets for 390, 3-wk-old weaned pigs. Initial weights averaged 4.8 and 5.5 kg in Trials 1 and 2, and trials were conducted for 5 and 4 wk, respectively. Diets in Trial 1 were formulated by substituting levels of 0, 4, 8, 12, 16 or 20% SMFM for soybean meal plus corn on a protein basis. The 20% fish meal diet contained no soybean meal; all diets contained between 19.8 and 20.2% CP, between 1.34 and 1.40% lysine and 25% dried whey. Replacement of soy protein with fish meal elicited a quadratic improvement (P = .01) in cumulative ADG and average daily feed intake (ADFI) by the end of wk 5. The diet containing 8% SMFM resulted in the maximum observed ADG; however, the maximum ADFI occurred in pigs fed the diet containing 12% SMFM. Breakpoint analysis indicated that 4.5 and 9.3% SMFM maximized ADG and ADFI, respectively. Addition of SMFM did not affect efficiency of feed utilization (F/G). In Trial 2, a 2 X 3 factorial with two levels of dried whey (10 or 20%) and three levels of SMFM (0, 4 or 8%), a SMFM X dried whey interaction (P less than .05) was observed for cumulative ADG and F/G by the of wk 4 with greater benefit from SMFM with 10% than with 20% dried whey.(ABSTRACT TRUNCATED AT 250 WORDS)

Adenosine transport systems on dissociated brain cells from mouse, guinea-pig, and rat

The kinetics and sodium dependence of adenosine transport were determined using an inhibitor-stop method on dissociated cell body preparations obtained from mouse, guinea-pig and rat brain. Transport affinity (KT) values for the high affinity adenosine transport systems (KT(H] were significantly different between these three species; mean +/- SEM values were 0.34 +/- 0.1 in mouse, 0.9 +/- 0.2 in rat, and 1.5 +/- 0.5 microM in guinea-pig. The KT values for the low affinity transport system (KT(L) were not different between the three species. Brain cells from rat displayed a significantly greater maximal capacity to accumulate [3H]adenosine (Vmax) than did mouse or guinea-pig for the high affinity system, or than did mouse for the low affinity system. When sodium chloride was replaced in the transport medium with choline chloride, the KT(H) values for guinea-pig and rat were both increased by approximately 100%; only in rat did the change reach statistical significance. The sodium-dependence of adenosine transport in mouse brain was clearly absent. The differences between KT(H) values in mouse and those in guinea-pig or rat were accentuated in the absence of sodium. The differences in kinetic values, ionic requirements, and pharmacological characteristics between adenosine transporters in CNS tissues of mouse, guinea-pig and rat may help account for some of the variability noted among species in terms of their physiological responses to adenosine.

HLA class I-related impairment in IL-2 production and lymphocyte response to microbial antigens in reactive arthritis

The contribution of certain Gram-negative bacteria and host HLA class I Ag to the development of reactive arthritis (ReA)3 has strong epidemiologic support but the pathogenesis of the arthritis is unknown. An outbreak of Salmonella typhimurium afforded the opportunity to compare the immune response to the organism between those who developed ReA (ReA+, n = 11) with those who did not (ReA-, n = 12). Of the 11 ReA+ patients, 4 were B27-positive and 6 were B7-positive; of the ReA- patients none was B27- or B7-positive. The causative pathogen S. typhimurium phage 22 was used to examine PBL proliferation by [3H]thymidine incorporation. Impairment in lymphocyte response to S. typhimurium in ReA+ compared with ReA- was demonstrated by: i) lower stimulation index (1.9 +/- 0.3 for ReA+, 5.7 +/- 0.6 for ReA-, p less than 0.01); ii) lower in vitro Ig production; and iii) lower Ag-induced IL-2 production. Mixing experiments did not demonstrate a soluble suppressor factor in ReA+ supernatants. Thus, after infection with S. typhimurium there is an impairment in cellular immunity that has correlates in immunogenetic and clinical features of the infected population.

HLA class I-related impairment in IL-2 production and lymphocyte response to microbial antigens in reactive arthritis

The contribution of certain Gram-negative bacteria and host HLA class I Ag to the development of reactive arthritis (ReA)3 has strong epidemiologic support but the pathogenesis of the arthritis is unknown. An outbreak of Salmonella typhimurium afforded the opportunity to compare the immune response to the organism between those who developed ReA (ReA+, n = 11) with those who did not (ReA-, n = 12). Of the 11 ReA+ patients, 4 were B27-positive and 6 were B7-positive; of the ReA- patients none was B27- or B7-positive. The causative pathogen S. typhimurium phage 22 was used to examine PBL proliferation by [3H]thymidine incorporation. Impairment in lymphocyte response to S. typhimurium in ReA+ compared with ReA- was demonstrated by: i) lower stimulation index (1.9 +/- 0.3 for ReA+, 5.7 +/- 0.6 for ReA-, p less than 0.01); ii) lower in vitro Ig production; and iii) lower Ag-induced IL-2 production. Mixing experiments did not demonstrate a soluble suppressor factor in ReA+ supernatants. Thus, after infection with S. typhimurium there is an impairment in cellular immunity that has correlates in immunogenetic and clinical features of the infected population.

Sodium-dependent uptake of nucleosides by dissociated brain cells from the rat

Sodium-dependent 3H-labeled nucleoside transport was studied using a mixed population of dissociated brain cells from adult rats. The accumulation of [3H]adenosine during brief (15-s) incubation periods was significantly greater in the presence of 110 mM Na+ than in its absence. This occurred at substrate concentrations that ranged from 0.25 to 100 microM. Similar findings were observed for the rapid accumulation of [3H]uridine. Kinetically, the rapid accumulation of [3H]adenosine in both the absence and the presence of Na+ was best described by a two-component system. In the presence of Na+, the KT and Vmax values for the high-affinity affinity component were 0.9 microM and 8.9 pmol/mg of protein/15 s, and those for the low-affinity component were 313 microM and 3,428 pmol/mg of protein/15 s, respectively. In the absence of Na+, the KT value for the high-affinity component was significantly higher (1.8 microM). [3H]Uridine accumulation was best described kinetically by a one-component system that in the presence of Na+ had KT and Vmax values of 1.0 mM and 2.6 nmol/mg of protein/15 s, respectively. As was found for [3H]adenosine, in the absence of Na+, the KT value was significantly higher (1.8 mM). The sodium-dependent transport of [3H]adenosine was inhibitable by ouabain and 2,4-dinitrophenol. Of the three nucleoside transport inhibitors tested, only nitrobenzylthioninosine demonstrated high affinity and selectivity in blocking the sodium component. Thus, high-affinity sodium-dependent nucleoside transport systems, in addition to facilitated diffusion systems, exist on brain cells from adult rats.

Postdysenteric reactive arthritis. A clinical and immunogenetic study following an outbreak of salmonellosis

Following an outbreak of foodborne gastroenteritis caused by Salmonella typhimurium, questionnaires were sent to affected individuals and then to the family physicians of any who experienced extra-enteric complications. Of 260 individuals infected with S typhimurium for whom adequate data were obtained, 19 patients developed joint disease (7.3%). All were men; the mean age +/- SD was 39.3 +/- 1.6 years. Among the 16 patients for whom this information was available, the interval from the onset of diarrhea to the onset of joint pain was less than 7 days in 7, 8-21 days in 2, and greater than 21 days in 7. There was a significantly longer duration of diarrhea in those patients with joint disease (mean +/- SEM 15.2 +/- 2.6 days) than in those without complications (10.0 +/- 1.1 days) (P less than 0.01). The joint disease was monarticular in 3 patients and polyarticular in 16. The joints most commonly affected were the elbow (47%), wrist (47%), knee (42%), low back (32%), and shoulder (32%). Six of the 19 patients had at least 1 extraarticular feature: ocular (5 patients), mucosal (1 patient), urethral (2 patients), or cutaneous (1 patient). Of these 19 patients, 11 were located and agreed to HLA typing. Four were positive for HLA-B27, 6 were HLA-B7 positive, and 1 had HLA-Bw60. Of the 4 B27 positive patients, 3 were DR1 positive; of the 6 B7 positive patients, 5 were DR2 positive.(ABSTRACT TRUNCATED AT 250 WORDS)

Pharmacological characterization of rapidly accumulated adenosine by dissociated brain cells from adult rat

Mechanically dissociated brain cells from adult rats were used to study biochemically and pharmacologically their capacity to accumulate rapidly [3H]adenosine. The assay, which used an inhibitor-stop method to prevent further uptake into cells, was characterized with respect to protein and optimal substrate concentrations, and incubation times that ranged from 5 to 180 s. The accumulation of [3H]adenosine using 15-s incubation periods, conditions under which less than 10% of accumulated [3H]adenosine was metabolized, was best described kinetically by a two-component system with Km and Vmax values for the high-affinity component of 0.8 microM and 6.2 pmol/mg protein/15 s and for the low-affinity component 259 microM and 2,217 pmol/mg protein/15 s, respectively. The potencies with which nucleosides, adenosine deaminase resistant adenosine receptor agonists, and nucleoside uptake inhibitors competed for these uptake components were determined. Of the nucleosides examined, adenosine was the "preferred" substrate for the uptake site. The Ki value of adenosine for the high-affinity component was 10.7 microM. Inosine and uridine competed for a single lower affinity uptake system: Ki values were 142 and 696 microM, respectively. Nucleoside uptake inhibitors--nitrobenzylthioinosine, dipyridamole, and dilazep--were the most potent inhibitors of [3H]adenosine accumulation tested: the Ki values for the high-affinity system were 0.11, 1.3, and 570 nM, respectively. The adenosine analogs S-phenylisopropyladenosine, R-phenylisopropyladenosine, and cyclohexyladenosine inhibited the high-affinity component with Ki values of 2.3, 9.3, and 14.5 microM, respectively. N-Ethylcarboxamidoadenosine competed for a single lower affinity uptake system: Ki, 292 microM.(ABSTRACT TRUNCATED AT 250 WORDS)

Clinical significance of common eye changes in older patients

The limbus is often affected by degenerative lesions, many associated with the aging process. Some degenerations may cause irritation, discomfort, and poor vision, thus requiring ophthalmological treatment, while a few require systemic evaluation and treatment. As the limbus is also subject to neoplasms and inflammatory processes, any limbal lesion whose identity is less than obvious should prompt an ophthalmologic consultation.

Successful treatment of the ocular ischemic syndrome with panretinal photocoagulation and cerebrovascular surgery

The ocular ischemic syndrome is a manifestation of chronic vascular insufficiency. The natural history is for progressive visual loss. The authors describe 12 patients (13 eyes) who presented with at least one asymmetric ocular finding, including midperipheral dot and blot hemorrhages (hypoperfusion retinopathy) (in 8), iris neovascularization (in 7), neovascular glaucoma (in 3) and vitreous hemorrhage (in 1). Cerebral angiography revealed stenosis or occlusion of the ipsilateral carotid artery in all cases. The treatment was panretinal photocoagulation (in four cases), cerebrovascular surgery (in three) or both (in six). All but one patient showed stabilization of visual acuity (20/60 or better in nine cases) and regression of proliferative retinopathy and of iris neovascularization. The results underline the importance of early recognition and treatment of the ocular ischemic syndrome.

Immunochemical analysis of immune response to Chlamydia trachomatis in Reiter's syndrome and nonspecific urethritis

Chlamydia trachomatis (Ct) has been proposed as a causative agent in Reiter's syndrome (RS) when an infection occurs in a susceptible host. To assess whether this susceptibility is reflected in a characteristic humoral immune response we compared patients with complicated (RS) and uncomplicated courses of nonspecific urethritis (NSU). Geometric mean titres of antibodies to C. trachomatis by immunofluorescence were 89.6 for RS, 80.0 for NSU and 16.0 for normals. 125I-Protein A probing of immunoblotted antigens of C. trachomatis revealed no band unique to RS. 125I-anti-IgA probing of immunoblots demonstrated reactivity with the 59,000 dalton antigen in 11/11 RS and 2/6 NSU. The major outer membrane protein of C. trachomatis (40,000 daltons) bound immunoglobulin nonspecifically. There was no clearly differentiating feature between HLA-B27-positive and B27-negative RS. One sequentially studied patient revealed an augmentation in synovial fluid IgA reactivity during the course of disease. No pattern of humoral immune response to C. trachomatis could be regarded as specific for RS nor for HLA B27-positivity. The study did not identify a Reiter's-specific antigen in C. trachomatis but demonstrates the usefulness of applying blotting techniques to population studies of HLA modulation of immune response to infectious agents.

Analysis of serum and synovial fluid IgA in Reiter's syndrome and reactive arthritis

The presumed antecedent infection which precedes Reiter's syndrome and reactive arthritis is frequently across a mucosal surface, and IgA immune responses may play a role in this process. Twelve of 29 patients with these conditions demonstrated elevation in serum IgA levels, and serum IgA levels in the postdysentery group (mean 3.21 g/liter +/- 1.27) were higher (P less than 0.01) than those in the posturethritis group (mean 2.40 g/liter +/- 0.80). In 10 of the 12 patients, IgA was the only immunoglobulin increased. There was no evidence of activation of complement in serum or synovial fluid. Using a complement-dependent assay, we were unable to demonstrate circulating IgA immune complexes. Sucrose density gradient ultracentrifugation analysis was used to assess IgA immune complexes in a non-complement-dependent manner. IgA of 11s was in fact demonstrated by this technique but appeared to be polymeric IgA on the basis of specific binding of secretory component and resistance to acid dissociation. IgA rheumatoid factor was not present. Synovial fluid revealed levels of polymeric IgA higher (mean 56.7% +/- 12.9) than did serum (23.7% +/- 13.9, P less than 0.001) despite higher levels of total IgA in serum than in synovial fluid (synovial fluid:serum ratio of IgA, mean 0.53 +/- 0.11). Although elevation in serum IgA in postdysenteric arthropathies suggests mucosal acquisition of antigen, the study does not implicate IgA circulating immune complexes in the pathogenesis of these diseases.

Arthritis, vasculitis, and cryoglobulinemia associated with relapsing hepatitis A virus infection

Hepatitis A virus, unlike hepatitis B virus, has rarely been associated with extrahepatic features. Two patients developed relapsing hepatitis A complicated by arthritis in both cases and cutaneous vasculitis in one. Both patients had cryoglobulinemia, with cryocrit values of 4.3% and 8.6%. Serologic studies showed that the cryoglobulin consisted of polyclonal IgM and IgG. The washed cryoglobulin was analyzed by sucrose density gradient ultracentrifugation under neutral (pH 7.4) and acidic (pH 2.8) conditions. Enzyme-linked immunosorbent assay techniques were used to characterize the native and dissociated cryoglobulin. The cryoglobulin contained acid-dissociable IgG complexes greater than 19S, and high molecular weight rheumatoid factors of both IgG and IgM isotypes that could be dissociated to 7S and 19S forms, respectively. Dissociation of the cryoglobulin augmented 7S anti-hepatitis A virus IgG 2.27-fold, but augmented total 7S IgG only 1.12-fold, suggesting enrichment of antiviral antibody in the cryoglobulin.

Molecular mimicry in Reiter's syndrome: cytotoxicity and ELISA studies of HLA-microbial relationships

The pathogenic links between HLA antigens, certain bacterial infections and arthritis have not yet been characterized. The hypothesis of cross-reactivity between HLA B27, the marker of disease susceptibility for these disorders, and the provocative microorganism has been suggested by studies of Klebsiella and ankylosing spondylitis. The present study examines the possibility of molecular mimicry between HLA B27 and two organisms implicated more directly in reactive arthritis, Yersinia enterocolitica and Chlamydia trachomatis. Antibodies against these organisms were obtained both from patients and from antisera raised in rabbits. Neither source of antibacterial antibody was specifically cytotoxic for HLA B27-positive lymphocytes, even when the target cells were derived from patients with recent infections due to these organisms. In addition, monoclonal antibodies against HLA B27 (M1 and M2) showed no reactivity with antigens from these organisms in an ELISA system. These data do not support the notion of molecular mimicry as being the basis of immunogenetic susceptibility to reactive arthritis and Reiter's syndrome following infections with Y. enterocolitica and C. trachomatis.

Hypertension control in two Canadian communities: evidence for better treatment and overlabelling

We evaluated the prevalence and control of hypertension in two Canadian cities without university medical centre facilities. A stratified multistage probability sample was selected, and we interviewed 6258 adults between the ages of 30 and 69 inclusive. Blood pressure measurements were obtained during home interviews. Up to two further visits were made to people with untreated blood pressure elevation. By a diagnostic criterion of 90 mmHg, the hypertension prevalence was 114/1000. Six per cent of the hypertensives were undetected, 6% detected but untreated, 17% treated but uncontrolled and 70% were being treated and controlled. Control was better in females and older subjects. These findings show no disadvantages to hypertensives living away from university medical centres. We found a hypertension prevalence of 143/1000 among people who reported being diagnosed as hypertensive but who had normal blood pressure while not on medication. These results suggest a problem with over-labelling of hypertensives.

Does a mailed continuing education program improve physician performance? Results of a randomized trial in antihypertensive care

Evidence is sparse concerning the value of the "educational" materials that physicians receive in the mail. We conducted a randomized trial of a mailed continuing education program on hypertension for primary care physicians. Although formal pretesting documented that the program led to significant improvements in physician knowledge over the short term, the current study showed no lasting effect on physician knowledge (mean scores on an end-of-study questionnaire were 50% and 52% for study and control physicians, respectively) and no influence on performance in lowering the blood pressures of patients referred from screening (mean blood pressure drop for study patients, 12.2/10.4 mm Hg vs 13.0/10.6 mm Hg for control patients). The chance that we missed a difference in diastolic blood pressure as great as 3 mm Hg is less than 5%. Resources spent on instructional materials mailed to physicians may be wasted.

Temporal desensitization of rat uteri for the decidual cell reaction is abolished by cholera toxin acting by a mechanism apparently not involving adenosine 3':5'-cyclic monophosphate

To determine if increased endometrial vascular permeability (a response which precedes decidualization) could be obtained in temporally nonsensitized uteri by treatments designed to increase endometrial adenosine 3':5'-cyclic monophosphate (cAMP) concentrations, cholera toxin (an activator of adenylate cyclase) was injected into the uterine lumen of immature rats treated to be at the equivalent of day 4, 5, or 6 of pseudopregnancy. In all experiments, the rats were pretreated with indomethacin to inhibit endogenous prostaglandin (PG) synthesis. Endometrial vascular permeability, determined using 125I-labeled bovine serum albumin, was assessed 8 h later. Cholera toxin increased endometrial vascular permeability to the same level in all groups. As determined by uterine weights 5 days after the intrauterine administration of cholera toxin or its vehicle, the toxin produced the same extent of decidualization in all groups. Cholera toxin had no detectable effect on uterine cAMP concentrations in rats sacrificed 15 min after intrauterine treatment. In contrast, intrauterine administration of PGE2 increased uterine cAMP concentrations at 15 min in all groups. These data suggest that the effects of cholera toxin and of PGE2 on endometrial vascular permeability and decidualization are not mediated by cAMP.

Giant retinal tears, retinal detachment and retinitis pigmentosa

A patient with retinitis pigmentosa and sensorineural deafness presented with bilateral giant retinal tears and a unilateral retinal detachment. The peripheral visual field loss could have been erroneously ascribed to the primary retinal dystrophy. A retinal detachment must be considered in patients with a sudden loss of visual acuity or field even if they have a primary retinal dystrophy.

Estrogen and uterine sensitization for the decidual cell reaction in the rat: role of prostaglandin E2 and adenosine 3':5'-cyclic monophosphate

The possibility that estrogen affects uterine sensitization for decidualization by altering the ability of E-series prostaglandins (PGs) to increase adenosine 3':5'-cyclic monophosphate (cAMP) concentrations was investigated. To determine if increased endometrial vascular permeability, a response which precedes decidualization, could be obtained in nonsensitized uteri by treatments designed to increase endometrial intracellular cAMP concentrations, cholera toxin, an activator of adenylate cyclase, was injected into the uterine lumen of immature rats pretreated with progesterone and either 0, 0.5 or 10 micrograms estrone with indomethacin to inhibit endogenous PG synthesis. Endometrial vascular permeability, determined using 125I-labeled bovine serum albumin, was assessed 8 h later. Cholera toxin produced a dose-dependent increase in endometrial vascular permeability in all groups; the uteri of rats pretreated with the optimal hormone regimen (0.5 micrograms estrone plus 2 mg progesterone) responded to a lower dose of the toxin. As determined by uterine weights and histologic examination 5 days after the intrauterine administration of cholera toxin or its vehicle, the toxin induced decidualization in rats pretreated with progesterone and 0 or 0.5 micrograms estrone, but not in those receiving 10 micrograms estrone. Cholera toxin had no detectable effect on uterine cAMP concentrations in animals sacrificed 15 min or 3 h after intrauterine treatment. The intrauterine injection of 8-Br-cAMP, with or without 3-isobutyl-1-methyl-xanthine, did not increase endometrial vascular permeability in indomethacin-treated animals pretreated with the different hormone regimens.(ABSTRACT TRUNCATED AT 250 WORDS)

Sexual behavior of group-housed stumptail macaques (Macaca arctoides): temporal, demographic and sociosexual relationships

A detailed quantitative analysis of sexual behavior in a social group of captive stumptail macaques was conducted. The distribution of copulations both over days and among animals, and the relationships between copulation and various sociosexual patterns were investigated. Copulations occurred erratically over days and were preferentially directed to a small minority of females. Most patterns of sociosexual behavior were at their highest rates during actual copulatory episodes, others occurred independent of ejaculation. It is suggested that the relationships between variables such as social rank, age and parity and sociosexual patterns are quite flexible and probably vary with the species, testing conditions and demographic make-up of the group.

Effects of labelling on income, work and social function among hypertensive employees

Two hundred and thirty hypertensive Canadian steelworkers were followed for 5 years after screening and referral. Data on income, absenteeism and measures of work and social function were collected on these men and on a matched group of 230 normotensive employees. In the fifth year after screening, hypertensive employees earned an average of Can. $1093 less than normotensive employees despite similar incomes in the year before screening. This adverse effect on income was observed regardless of awareness of hypertension at the time of screening or compliance with treatment. Illness-related absenteeism among hypertensives rose in the year following screening and remained elevated for 4 years after screening. Normotensive and hypertensive employees reported similar levels of physical ability and psychological well-being. These findings need verification in other settings before inclusion in cost-effectiveness analyses of the management of hypertension.