Childhood-Onset Lupus Nephritis in the Childhood Arthritis and Rheumatology Research Alliance Registry: Short-Term Kidney Status and Variation in Care

OBJECTIVE

The goal was to characterize short-term kidney status and describe variation in early care utilization in a multicenter cohort of patients with childhood-onset systemic lupus erythematosus (cSLE) and nephritis.

METHODS

We analyzed previously collected prospective data from North American patients with cSLE with kidney biopsy-proven nephritis enrolled in the Childhood Arthritis and Rheumatology Research Alliance (CARRA) Registry from March 2017 through December 2019. We determined the proportion of patients with abnormal kidney status at the most recent registry visit and applied generalized linear mixed models to identify associated factors. We also calculated frequency of medication use, both during induction and ever recorded.

RESULTS

We identified 222 patients with kidney biopsy-proven nephritis, with 64% class III/IV nephritis on initial biopsy. At the most recent registry visit at median (interquartile range) of 17 (8-29) months from initial kidney biopsy, 58 of 106 patients (55%) with available data had abnormal kidney status. This finding was associated with male sex (odds ratio [OR] 3.88, 95% confidence interval [95% CI] 1.21-12.46) and age at cSLE diagnosis (OR 1.23, 95% CI 1.01-1.49). Patients with class IV nephritis were more likely than class III to receive cyclophosphamide and rituximab during induction. There was substantial variation in mycophenolate, cyclophosphamide, and rituximab ever use patterns across rheumatology centers.

CONCLUSION

In this cohort with predominately class III/IV nephritis, male sex and older age at cSLE diagnosis were associated with abnormal short-term kidney status. We also observed substantial variation in contemporary medication use for pediatric lupus nephritis between pediatric rheumatology centers. Additional studies are needed to better understand the impact of this variation on long-term kidney outcomes.

Intraarticular steroids as DMARD-sparing agents for juvenile idiopathic arthritis flares: Analysis of the Childhood Arthritis and Rheumatology Research Alliance Registry

BACKGROUND

Children with juvenile idiopathic arthritis (JIA) who achieve a drug free remission often experience a flare of their disease requiring either intraarticular steroids (IAS) or systemic treatment with disease modifying anti-rheumatic drugs (DMARDs). IAS offer an opportunity to recapture disease control and avoid exposure to side effects from systemic immunosuppression. We examined a cohort of patients treated with IAS after drug free remission and report the probability of restarting systemic treatment within 12 months.

METHODS

We analyzed a cohort of patients from the Childhood Arthritis and Rheumatology Research Alliance (CARRA) Registry who received IAS for a flare after a period of drug free remission. Historical factors and clinical characteristics and of the patients including data obtained at the time of treatment were analyzed.

RESULTS

We identified 46 patients who met the inclusion criteria. Of those with follow up data available 49% had restarted systemic treatment 6 months after IAS injection and 70% had restarted systemic treatment at 12 months. The proportion of patients with prior use of a biologic DMARD was the only factor that differed between patients who restarted systemic treatment those who did not, both at 6 months (79% vs 35%, p < 0.01) and 12 months (81% vs 33%, p < 0.05).

CONCLUSION

While IAS are an option for all patients who flare after drug free remission, it may not prevent the need to restart systemic treatment. Prior use of a biologic DMARD may predict lack of success for IAS. Those who previously received methotrexate only, on the other hand, are excellent candidates for IAS.

National audit of non-melanoma skin cancer excisions performed by plastic surgery in the UK

A national, multi-centre audit of non-melanoma skin cancer excisions by plastic surgery.

Paroxysmal atrial fibrillation ablation with a novel flexible tip radiofrequency catheter incorporating contact force sensing: acute results of the TactiFlex AF IDE trial

Background

Catheter ablation is an established therapy for paroxysmal atrial fibrillation (PAF). The TactiFlex™ Ablation Catheter, Sensor-Enabled™ (TactiFlex SE) is a next-generation radiofrequency ablation catheter incorporating highly accurate fiber optics-based contact force sensing technology with a flexible, laser-cut tip.

Purpose

To demonstrate that ablation with TactiFlex SE is safe and effective for the treatment of drug refractory, symptomatic PAF.

Methods

The TactiFlex AF IDE is a prospective, non-randomized, multi-center clinical study which enrolled 355 subjects worldwide. Enrollment in the main study began on June 26, 2020 and completed on June 18, 2021. Subjects underwent de novo Pulmonary Vein Isolation (PVI) and, if indicated, a Cavotricuspid Isthmus ablation (CTI line) for CTI-dependent atrial flutter.

Results

Subjects were divided into two as treated subgroups: High Standard Power (HSP, n=189), defined as subjects with 100% of left atrial lesions ablated at ≥40 W, and Low Standard Power (LSP, n=119), defined as subjects with at least one left atrial lesion ablated at &lt;40W. First pass success, defined as isolation of all pulmonary veins (PVs) confirmed after a minimum 20 min waiting period was achieved in 93.5% (175/186) and 84.5% (98/116) of HSP and LSP subjects, respectively (p=0.0104). Significant decreases in the HSP versus LSP procedures were also seen in total procedure time (112.0 min [89.0, 139.5] and 149.0 [115.0, 182.0], respectively [p&lt;0.001]), total RF time for PV ablation (14.0 min [11.0, 19.0] and 29.0 [19.0, 41.0], respectively [p&lt;0.0001]), total fluoroscopy time (4.0 min [0.0, 11.0] and 8.0 [3.0, 17.0], respectively [p&lt;0.0001]) and irrigation fluid volume (378.0 mL [310.0, 466.0] and 636.0 [476.0, 829.0], respectively [p&lt;0.0001]) (values given as Median [Q1, Q3]), see Figure 1. Both HSP and LSP subjects had a low rate of repeat procedures (1.6% [3/182] and 4.3% [5/115], respectively [p=0.2684]) and primary safety endpoint events (4.8% [9/189] and 4.2% [5/119], respectively [p=0.8182]) through 90 days post-index procedure.

Conclusion

The acute data on the TactiFlex SE catheter demonstrates safe and effective treatment of PAF using either a HSP or LSP ablation strategy. Ablation procedures performed using a HSP strategy were shorter and required less irrigation fluid and fluoroscopy. It is anticipated these results will be reflected in the 12-month safety and effectiveness primary endpoints.

Funding Acknowledgement

Type of funding sources: Private company. Main funding source(s): Abbott

Acute results of a novel flexible tip radiofrequency catheter incorporating contact force sensing

Funding Acknowledgements

Type of funding sources: Private company. Main funding source(s): Abbott

Background

Catheter ablation is an established therapy for paroxysmal atrial fibrillation (PAF). The TactiFlex Ablation Catheter, Sensor-Enabled (TactiFlex SE) is a next-generation radiofrequency ablation catheter incorporating highly accurate fiber optics-based contact force sensing technology with a flexible, laser-cut tip. This is the first report of results from the TactiFlex IDE clinical study.

Purpose

To demonstrate that ablation with TactiFlex SE is safe and effective for the treatment of drug refractory, symptomatic PAF.

Methods

The TactiFlex IDE (NCT04356040) is a prospective, non-randomized, multi-center clinical study which enrolled 305 subjects worldwide in the main study. Enrollment in the main study began on June 26, 2020 and completed on June 8, 2021. Subjects underwent de novo Pulmonary Vein Isolation (PVI) and, if indicated, a Cavotricuspid Isthmus ablation (CTI line) for CTI-dependent atrial flutter.

Results

Acute procedural success was achieved in 98.6% (274/278) of the main study cohort who underwent an ablation procedure using the TactiFlex SE. First pass success, defined as isolation of all pulmonary veins (PVs) confirmed after a minimum 20 min waiting period was achieved in 89.6% (249/278) of subjects. This was a significant improvement versus the TactiSense IDE trial (TactiCath Ablation Catheter, Sensor-Enabled). Significant decreases were also seen in total procedure time (123 min [101.0, 163.5]), total PV ablation time (55.5 min [35.0, 81.0]), total fluoroscopy time (6.0 min [0.0, 13.0]) and irrigation fluid volume (450.0 mL [346.0, 636.0]) (values given as Median [Q1, Q3]), see FIGURE. All subjects have completed at least 90 days of follow-up. Only 2.6% (7/271) of subjects required a repeat procedure during the 90-day blanking period. The primary safety and effectiveness endpoints will be evaluated at 12-months. At 90 days, 4.3% (12/281) subjects had experienced a primary safety endpoint event.

Conclusions

The acute data from the TactiFlex IDE clinical study demonstrate safety and effectiveness of the TactiFlex SE catheter in the treatment of PAF. Ablation procedures performed using the next-generation TactiFlex SE catheter were shorter and had improved acute clinical effectiveness outcomes versus the TactiSense IDE. It is anticipated these results will also be reflected in the 12-month safety and effectiveness endpoints.

Social determinants of health influence disease activity and functional disability in Polyarticular Juvenile Idiopathic Arthritis

BACKGROUND

Social determinants of health (SDH) greatly influence outcomes during the first year of treatment in rheumatoid arthritis, a disease similar to polyarticular juvenile idiopathic arthritis (pJIA). We investigated the correlation of community poverty level and other SDH with the persistence of moderate to severe disease activity and functional disability over the first year of treatment in pJIA patients enrolled in the Childhood Arthritis and Rheumatology Research Alliance Registry.

METHODS

In this cohort study, unadjusted and adjusted generalized linear mixed effects models analyzed the effect of community poverty and other SDH on disease activity, using the clinical Juvenile Arthritis Disease Activity Score-10, and disability, using the Child Health Assessment Questionnaire, measured at baseline, 6, and 12 months.

RESULTS

One thousand six hundred eighty-four patients were identified. High community poverty (≥20% living below the federal poverty level) was associated with increased odds of functional disability (OR 1.82, 95% CI 1.28-2.60) but was not statistically significant after adjustment (aOR 1.23, 95% CI 0.81-1.86) and was not associated with increased disease activity. Non-white race/ethnicity was associated with higher disease activity (aOR 2.48, 95% CI: 1.41-4.36). Lower self-reported household income was associated with higher disease activity and persistent functional disability. Public insurance (aOR 1.56, 95% CI 1.06-2.29) and low family education (aOR 1.89, 95% CI 1.14-3.12) was associated with persistent functional disability.

CONCLUSION

High community poverty level was associated with persistent functional disability in unadjusted analysis but not with persistent moderate to high disease activity. Race/ethnicity and other SDH were associated with persistent disease activity and functional disability.

Comparison of geographic workflow preferences with real-time dynamic regional mapping data during catheter ablation

Funding Acknowledgements

Type of funding sources: None.

Introduction

The clinical benefit of multielectrode high-density (HD) mapping during catheter ablation has been an area of active research. One advantage of HD mapping is improved sensitivity which can lead to better visualization and substrate delineation during the procedure. In addition to the advantages offered by the multielectrode grid mapping catheter (HD Grid), a novel software enable the display of beat-to-beat, dynamic regional mapping data from the current location of HD Grid in real-time (LiveView). The optimal settings and workflows to incorporate the dynamic data into routine ablation procedures have not been explored.

Purpose

To examine the common settings and workflow patterns among operators from different geographies when using dynamic mapping.

Methods

Observational procedural data including procedure time, total RF time, workflow preference, and fluoroscopy time, were prospectively collected from operators across Europe, the U.S., and Asia Pacific countries from May to September 2020. Cases from both catheter ablation of atrial and ventricular arrhythmias were included in the analysis.

Results

A total of 754 cases were collected (428, 133, and 193 cases from Europe, the U.S., and the Asia Pacific region, respectively). The most commonly reported indication across all three geographies was de novo paroxysmal atrial fibrillation (223/754, 30.0%). A steerable sheath was more frequently used with the mapping catheter in Europe and U.S. compared to Asia Pacific countries. Contrary to cases from the U.S. and Asia Pacific countries where the double transseptal approach was the preferred technique for left atrial procedures (78.8% and 55.3%, respectively), the single transseptal approach was more commonly observed in European cases (233/428, 54.4%). Visualization of real-time mapping data after creation of traditional full-chamber maps were commonly observed in all three geographies. Regardless of geography, the CS catheter was commonly used a reference electrode; and the most common map appearance settings for interior projection, exterior projection, and interpolation was 7, 7, and 7 respectively. Voltage cutoff of 0.1 mV, range from 0.01 to 1.5 mV, was most frequently observed for delineating scar in atrial arrhythmia cases analyzed in this dataset.

Conclusions

While there is a geographical difference in ablation workflow, common settings and patterns can be observed in all three regions. This data suggests that minimal workflow changes are required to incorporate the use of dynamic data into routine procedures. Adaptation of LiveView can help improve procedure efficiency and efficacy by reducing the need for full chamber maps, identifying areas that were under ablated, and confirming ablation endpoints. Further control study examining procedure efficiency and efficacy associated with dynamic mapping may be warranted.

0032 Timing of Daily Rhythm of Cardiac Autonomic Control Contributes to Weight Loss Resistance, Independent of Daily Energy Intake and Physical Activity Level

Introduction

Obesity is a major health problem. Many treatments have been designed to help overweight/obese people to lose weight, but their effectiveness is highly variable. The same treatments may work for some persons while others have no responses — weight loss resistance. We tested whether the daily rhythm of cardiac autonomic control contributes to weight loss resistance.

Methods

We studied 39 overweight/obese Caucasian women (BMI&gt;25; age: 21–62 years old) who completed (1) an obesity dietary treatment of up to 30 weeks with weekly assessments of body weight, and (2) ambulatory monitoring of electrocardiogram (ECG) for up to 3.5 days. Heartbeat intervals were derived from ECG. Cardiac autonomic control was assessed in each 1-h bin by examining the temporal correlation in heartbeat fluctuations — a nonlinear measure that quantifies the delicate dynamic interplay between sympathetic and vagal outflows. Daily rhythm was estimated using the cosinor analysis.

Results

Weight loss was highly variable (range: 0.68%-21.78 % of initial body weight). The correlation in heartbeat fluctuations displayed a 24-h rhythm (p&lt;0.0001) with fewer correlations (more random) during the nighttime. The phase (peak timing) of the rhythm was highly variable, i.e., 10AM to 8PM for most participants, and after midnight in four participants. Weight loss evolution depended on the phase (p=0.006) in a nonlinear manner. Specifically, participants with the phase between 2PM-8PM lost weight faster than those with phases before 2PM and those after 8PM. The effect was independent of total energy intake, physical activity level, and sleep/wake schedules.

Conclusion

Cardiac autonomic control in overweight/obese women displayed a daily rhythm. The timing of the rhythm had previously un-identified contributions to weight loss. The inter-individual differences in the timing may reflect different circadian regulation of autonomic function and its interaction with the daily behavioral cycle.

Support

This work was supported by NIH grants R01AG048108, RF1AG059867, RF1AG064312, R01AG017917, and R01NS078009.

A case–control study analyzing mannitol dosing for prevention of cisplatin-induced acute nephrotoxicity

Background

Mannitol is an osmotic diuretic given routinely as part of cisplatin regimens to prevent nephrotoxicity, but there are limited data on the ideal dosage. At our center, three different doses of mannitol are used: 12, 20, and 40 g per cycle for cisplatin doses of ≥50 mg/m2. The primary objective was to determine if variations in mannitol dosing significantly influence the incidence of cisplatin-induced acute nephrotoxicity.

Methods

A case–control study was performed. Electronic records of 1462 consecutive outpatients who received cisplatin at ≥ 50 mg/m2 per cycle between January 2010 and December 2014 were reviewed. Patients experiencing nephrotoxicity of any grade within 30 days of last cisplatin dose, as defined by NCI CTCAE 4.0, were matched to a minimum of two and maximum of five controls based on the following criteria: age ± 5 years, baseline estimated glomerular filtration rate ± 10 ml/min/1.73 m2, cisplatin dose per cycle, and presence of diabetes. Conditional logistic regression was used to identify baseline predictors of cisplatin-induced acute nephrotoxicity.

Results

Of the 1245 included patients, 237 had nephrotoxicity and 1008 were matched controls. Median baseline estimated glomerular filtration rate for cases and controls were 83 and 80 ml/min/1.73 m2, respectively. A total of 3.8% of cases experienced ≥ grade 3 nephrotoxicity. Univariable analysis showed that diabetes, lymphoma, low baseline estimated glomerular filtration rate, and low baseline magnesium level were significantly associated with nephrotoxicity, whereas mannitol dosing did not show any association (odds ratio 1.08; p = 0.29). In multivariable analysis, diabetes and lymphoma retained statistical significance, but baseline estimated glomerular filtration rate and baseline magnesium level showed nonsignificant associations with nephrotoxicity.

Conclusions

Cisplatin-induced acute nephrotoxicity remains common in patients with good baseline renal function despite preventive measures. Diabetes and lymphoma are predictors of nephrotoxicity, whereas mannitol dosing has no significant influence, suggesting that doses may be standardized across cisplatin regimens.

The antenatal urinary tract dilation classification system accurately predicts severity of kidney and urinary tract abnormalities

BACKGROUND

Urinary tract dilation (UTD) is a commonly diagnosed prenatal condition; however, it is currently unknown which features lead to benign and resolving or pathologic abnormalities. A consensus UTD classification system (antenatal UTD classification, UTD-A) was created by Nguyen et al. in 2014 [1], but has not yet been validated.

OBJECTIVE

To evaluate the ability of the UTD-A system to identify kidney and urinary tract (KUT) abnormalities, assess whether UTD-A can predict severity of KUT conditions, and perform a cost analysis of screening ultrasound (US).

METHODS

A retrospective single-center study was conducted at an academic medical center. Inclusion criteria were: neonates in the well or sick nursery who had a complete abdominal or limited renal US performed in the first 30 days of life between January 01, 2011 and December 31, 2013. Data were collected on prenatal US characteristics from which UTD-A classification was retrospectively applied, and postnatal data were collected up to 2 years following birth.

RESULTS

A total of 203 patients were identified. Of the 36 abnormal postnatal KUT diagnoses, 90% were identified prenatally as UTD A1 or UTD A2-3. The remaining 10% developed postnatal KUT abnormalities due to myelomeningocele, such as VUR or UTD, which were not evident prenatally. Overall sensitivity and specificity of the UTD-A system was 0.767 (95% CI 0.577, 0.901) and 0.836 (95% CI 0.758, 0.897), respectively, when resolved UTD was counted as a normal diagnosis. Postnatal diagnoses differed by UTD-A classification as shown in the Summary fig. Of all the obstructive uropathies, 90.9% occurred in the UTD A2-3 class and none occurred in UTD-A Normal. Rate of postnatally resolved UTD was significantly higher in the UTD A1 group (78%) compared with UTD A2-3 (31%) or UTD-A Normal (12%, all P < 0.001). There was a notable trend towards more UT surgeries, UTI, and positive VUR among UTD A2-3 patients, but statistical significance was limited by a small number of patients.

CONCLUSIONS

This study found that the UTD-A classification system revealed important differences in the severity of UTD abnormalities. With repeated validation in larger cohorts, the UTD-A classification may be used to offer a prognosis for parents regarding prenatally diagnosed KUT conditions. Larger prospective studies should be designed to validate whether the UTD-A system can predict postnatal events related to UTD morbidity such as need for UT-related surgery or UTI.

The Picture Multiple: Figuring, Thinking, and Knowing in Descartes's Essais (1637)

Throughout his Essais (1637), Descartes appropriated the visual language of practical mathematics in order to forge a new natural philosophy. This article argues that by grafting geometric line onto descriptive figure, the philosopher and his illustrator, Frans van Schooten Jr., underscored doubts about a natural philosophy based on qualities, all the while situating his new epistemology in the 17th-century present and exercising a deep attention to the differences between nature seen, nature pictured, and nature understood.

Acclimation potential of Arctic cod (Boreogadus saida) from the rapidly warming Arctic Ocean

As a consequence of the growing concern about warming of the Arctic Ocean, this study quantified the thermal acclimation responses of Boreogadus saida, a key Arctic food web fish. Physiological rates for cardio-respiratory functions as well as critical maximum temperature (T_c,max) for loss of equilibrium (LOE) were measured. The transition temperatures for these events (LOE, the rate of oxygen uptake and maximum heart rate) during acute warming were used to gauge phenotypic plasticity after thermal acclimation from 0.5°C up to 6.5°C for 1 month (respiratory and T_c,max measurements) and 6 months (cardiac measurements). T_c,max increased significantly by 2.3°C from 14.9°C to 17.1°C with thermal acclimation, while the optimum temperature for absolute aerobic scope increased by 4.5°C over the same range of thermal acclimation. Warm acclimation reset the maximum heart rate to a statistically lower rate, but the first Arrhenius breakpoint temperature during acute warming was unchanged. The hierarchy of transition temperatures was quantified at three acclimation temperatures and was fitted inside a Fry temperature tolerance polygon to better define ecologically relevant thermal limits to performance of B. saida We conclude that B. saida can acclimate to 6.5°C water temperatures in the laboratory. However, at this acclimation temperature 50% of the fish were unable to recover from maximum swimming at the 8.5°C test temperature and their cardio-respiratory performance started to decline at water temperatures greater than 5.4°C. Such costs in performance may limit the ecological significance of B. saida acclimation potential.

Understanding the interaction between physicians and pharmacists as a method of quality improvement

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Background: Pharmacists and pharmacy technicians are essential to safe medication delivery. Filling prescriptions can be time consuming when the prescription is not complete or clear and requires inter-professional communication. To improve the quality and efficiency of dispensing medication we performed an audit of callbacks to physicians in the outpatient pharmacy associated with our cancer center with a focus on oral chemotherapy. Methods: The Princess Margaret is one of the largest cancer centers in the world, with an outpatient pharmacy on the premises that fills over 70,000 prescriptions a year. The pharmacists have access to the hospital’s Health Information System and chemotherapy prescribing system. A Prescription Audit Form was developed to track the mode of oral chemotherapy prescription (handwritten, preprinted, computerized physician order entry (CPOE), verbal) and reason for callback. The form was implemented from February 10th until March 7th, 2014 with coded data collection. The form was incorporated into the normal workflow of the outpatient pharmacy and concurrently used to document pharmacy interactions for billing purposes. Results: A total of 5,546 prescriptions were filled with 1,166 prescriptions for oral chemotherapy. Nine percent of prescriptions for oral chemotherapy required a callback to a physician and accounted for 32% of the total callbacks made to physicians. Of the 1,166 oral chemotherapy prescriptions; 39% were refills, 34% were handwritten, 22% were CPOE, 4% were verbal, 1% were preprinted, and 1% were not documented. The top two reasons for callbacks were; drug interaction (32%) and incorrect dose (24%). In the 9% of cases where the physician was contacted to clarify a prescription, the prescription was changed 43% of the time. Conclusions: Understanding the reasons for callbacks can be used to determine optimal data fields required in oral chemotherapy prescribing. Ensuring that prescriptions are appropriately completed will reduce the number of callbacks to physicians - significantly impacting the workflow and efficiency of the pharmacy. Reducing unnecessary callbacks will allow the pharmacy team to deliver timely, safe and effective patient centered care.

Stakeholder perspectives on transitions of nursing home residents to hospital emergency departments and back in two Canadian provinces

Major gaps exist in our understanding of transitions in care for older persons living in nursing homes. The purpose of the study was to identify key elements, from multiple stakeholder perspectives, that influence the success of transitions experienced by nursing home residents when they required transfer to a hospital emergency department. This interpretive descriptive study was conducted in two cities in the Canadian provinces of British Columbia and Alberta. Data were collected from 71 participants via focus groups and individual interviews with nursing home residents, family members, and professional healthcare providers working in nursing homes, emergency departments, and emergency medical services. Transcripts were analyzed using constant comparison. The elements contributing to the success of transitions reflected a patient- and family-centered approach to care. Transitions were influenced by the complex interplay of multiple elements that included: knowing the resident; critical geriatric knowledge and skilled assessment; positive relationships; effective communication; and timeliness. When one or more of the elements was absent or compromised, the success of the transition was also compromised. There was consistency about the importance of all the identified elements across all stakeholder groups whether they are residents, family members, or health professionals in nursing homes, emergency departments or emergency medical services. Aspects of many of these elements are modifiable and suggest viable targets for interventions aimed at improving the success of transitions for this vulnerable population.

Effect of Misalignment between Hospital and Provincial Formularies on Medication Discrepancies at Discharge: PPITS (Proton Pump Inhibitor Therapeutic Substitution) Study

BACKGROUND

Medication discrepancies may occur on admission, transfer, or discharge from hospital. Therapeutic interchange within a drug class is a common practice in hospitals, and orders for specific proton pump inhibitors (PPIs) are often substituted with the hospital's formulary PPI through therapeutic interchange protocols. Rabeprazole is the PPI on the formulary of the British Columbia PharmaCare program. However, different PPIs may appear on the formularies of the province's hospitals. This misalignment and use of therapeutic interchange may lead to increased rates of medication discrepancies at the time of discharge.

OBJECTIVE

To evaluate the effect of formulary misalignment for PPIs between St Paul's Hospital in Vancouver and the British Columbia PharmaCare program and use of therapeutic interchange on the occurrence of medication discrepancies at discharge.

METHODS

A cohort chart review was performed to compare discharge discrepancy rates for PPI orders between 2 periods: June 2006 to June 2008, when the same PPI appeared on the hospital and provincial formularies, and July 2008 to July 2010, when the designated PPIs differed between the hospital and provincial formularies. Data for the first study period were used to establish the baseline discharge discrepancy rate, and data for the later period represented the discharge discrepancy rate in the presence of misalignment between the hospital and PharmaCare formularies.

RESULTS

The discharge discrepancy rate for PPIs was 27.3% (24/88) when the 2 formularies were aligned and 49.1% (81/165) when the formularies were misaligned. This represents an absolute increase of 21.8 percentage points in the risk of discharge discrepancies (95% confidence interval 9.8-33.9 percentage points; p < 0.001) when the hospital and provincial formularies were misaligned and the hospital's therapeutic interchange protocol was used.

CONCLUSIONS

Misalignment between the PPIs specified in the hospital and provincial formularies, combined with use of therapeutic interchange, was associated with a significant increase in medication discrepancies at discharge.

P2-14-10: Are There Variations in Invasive Tumour Characteristics between Different Ethnic Groups?

Introduction: Studies have shown that ethnic minorities with breast cancer are more likely to present at a younger age and with more aggressive tumours. The aim of this study was to examine the variation in tumour characteristics and surgical outcomes in different ethnic groups in our breast unit over a 12-month period.

Methods: A retrospective study was performed on all patients with a new diagnosis of breast cancer, either screen-detected or symptomatic, between January to December 2009. Using our Trust databases, data on patient demographics, tumour characteristics, and ethnicity were collected. Where ethnicity was not documented, patients were contacted by telephone to complete the database. Those unable to be contacted were excluded from the study. Other exclusion criteria include those with recurrent ipsilateral breast cancer.

Results: A total of 270 patients (265 females) were included in our study, of which 235 (87%) had invasive cancers (ductal carcinoma, lobular carcinoma, tubular carcinoma, mucinous carcinoma, cribriform carcinoma, papillary carcinoma, sarcoma) and the remaining 35 patients (13%) had non-invasive cancers (ductal carcinoma in-situ, lobular carcinoma in-situ, papilloma, columnar cell hyperplasia).

We were unable to contact 23 (8.5%) patients to ascertain their ethnicity, and therefore these have been excluded from our results.

Potential use of the anti-inflammatory drug, sulfasalazine, for targeted therapy of pancreatic cancer

Pancreatic cancer is an aggressive, drug-resistant disease; its first-line chemotherapeutic, gemcitabine, is only marginally effective. Intracellular depletion of glutathione, a major free-radical scavenger, has been associated with growth arrest and reduced drug resistance (chemosensitization) of cancer cells. In search of a new therapeutic approach for pancreatic cancer, we sought to determine whether specific inhibition of the plasma membrane x(c) (-) cystine transporter could lead to reduced uptake of cysteine, a key precursor of glutathione, and subsequent glutathione depletion. Sulfasalazine (approximately 0.2 mmol/L), an anti-inflammatory drug with potent x(c) (-)-inhibitory properties, markedly reduced l¹⁴C]-cystine uptake, glutathione levels, and growth and viability of human MIA PaCa-2 and PANC-1 pancreatic cancer cells in vitro. These effects were shown to result primarily from inhibition of cystine uptake mediated by the x(c) (-) cystine transporter and not from inhibition of nuclear factor kappaB activation, another property of sulfasalazine. The efficacy of gemcitabine could be markedly enhanced by combination therapy with sulfasalazine both in vitro and in immunodeficient mice carrying xenografts of the same cell lines. No major side effects were observed in vivo.The results of the present study suggest that the x(c) (-) transporter plays a major role in pancreatic cancer by sustaining or enhancing glutathione biosynthesis, and as such, represents a potential therapeutic target. Sulfasalazine, a relatively nontoxic drug approved by the U.S. Food and Drug Administration, may, in combination with gemcitabine, lead to more effective therapy of refractory pancreatic cancer.

High rate of increased carotid intima-media thickness and atherosclerotic plaques in Chinese asymptomatic subjects with central obesity

Both central obesity and increased carotid intima-media thickness (IMT) are markers of atherosclerosis and associated with cardiovascular diseases (CVD). Information of IMT in Chinese subjects with central obesity is limited. This study was performed to assess the rate of atherosclerosis and abnormal IMT in asymptomatic Chinese subjects with central obesity, and to investigate the association between IMT values and CVD risk factors including hypertension, hyperglycaemia and dyslipidaemia. We studied 122 centrally obese adults who had good past health. IMT measurements on carotid arteries were performed and fasting blood taken for plasma glucose and lipid profiles. Abnormal IMT was defined as > 0.9 mm. Atherosclerosis was defined as the presence of one or more visible plague. Of the 122 subjects, the mean (±SD) age was 59.4 ± 5.8 years (median [range]: 59.0 [45-75] years). The median IMT value was 0.70 mm (range: 0.53-1.19 mm) [men vs. women: 0.74 mm vs. 0.66 mm, P-value: < 0.001]. IMT values and the rate of atherosclerosis increased with age and the number of CVD risk factors (P-value for trend: < 0.05). Using binary logistic regression to predict the presence of atherosclerosis with the presence of abnormal IMT, age, gender, and other CVD risk factors as independent variables, age (OR [95% CI] = 1.13 [1.03, 1.23], P = 0.009) and abnormal IMT (OR [95% CI] = 4.05 [1.09, 15.03], P = 0.037) were independently associated with atherosclerosis. In conclusion, among Hong Kong Chinese asymptomatic subjects with central obesity, there was a high rate of CVD risk factors. We found that 19% of these subjects had carotid atherosclerotic plaques and 10% of them had abnormal IMT (>0.9 mm). Carotid IMT study may serve as an appropriate screening tool to diagnose atherosclerosis in the centrally obese middle-aged population.

The xc- cystine/glutamate antiporter: a mediator of pancreatic cancer growth with a role in drug resistance

The x_c⁻ cystine transporter enhances biosynthesis of glutathione, a tripeptide thiol important in drug resistance and cellular defense against oxidative stress, by enabling cellular uptake of cystine, a rate-limiting precursor. Because it is known to regulate glutathione levels and growth of various cancer cell types, and is expressed in the pancreas, we postulate that it is involved in growth and drug resistance of pancreatic cancer. To examine this, we characterised expression of the x_c⁻ transporter in pancreatic cancer cell lines, MIA PaCa-2, PANC-1 and BxPC-3, as subjected to cystine-depletion and oxidative stress. The results indicate that these cell lines depend on x_c⁻-mediated cystine uptake for growth, as well as survival in oxidative stress conditions, and can modulate x_c⁻ expression to accommodate growth needs. Immunohistochemical analysis showed that the transporter was differentially expressed in normal pancreatic tissues and overexpressed in pancreatic cancer tissues from two patients. Furthermore, gemcitabine resistance of cells was associated with elevated x_c⁻ expression and specific x_c⁻ inhibition by monosodium glutamate led to growth arrest. The results suggest that the x_c⁻ transporter by enhancing glutathione biosynthesis plays a major role in pancreatic cancer growth, therapy resistance and represents a potential therapeutic target for the disease.

[Assessment of surgical treatment of olecranon fractures by tension-band wiring. About 63 cases]

The purpose of this work is to estimate our anatomical and functional results of the surgical technique based on the AO principle of tension band wiring. We led a retrospective continuous study on the basis of 70 files brought together from January, 1999 till December, 2006. We had included all the patients who presented a recent fracture of the olecranon treated by tension band wiring and having a follow-up more than 6 month. Seven (7) files were excluded giving to the study one population of 63 patients. The fracture was classified according to the classification of Mayo clinic and the associated hurts were noted. The tension band wiring was the exclusive treatment. The evaluation looked for the complications and appreciated the radiological and functional results according to the score of Mayo Elbow Performance Score. We had found 48 fractures of type II and 15 fractures of type III. There were 5 cases of cutaneous punctiforme opening, a fracture of the ipsilateral forearm in 3 cases, a fracture of the thighbone in 1 case and a dislocation of the elbow associated with a fracture of the humerus in 1 case. The consolidation was obtained at 60 patient's at the end of 4 months on average (extremes: 3 and 6 months). There were 3 cases of non union and 5 cases of pins migrations. On the functional plan, we obtained 15 very good results, 26 good results, 19 average results and 3 bad results. The most frequent and the most common fractures of the elbow, the olecranon fractures treated by tension band wiring give good results.

[Myorelaxant and antispasmodic activity of ethanolic total extract's fractions of roots of Cassia sieberiana D.C. (Caesalpiniaceae) on isolated wistar rat ileum]

INTRODUCTION

Cassia sieberiana DC (CAESALPINIACEAE) is a plant which grows in Southern Senegal. Its roots are used by traditional medicinal practitioners for its s pasmolytic and antiparasitic properties. The objective of our study was to investigate the myorelaxant and antispasmodic activity of the roots of C. sieberiana on the isolated Wistar rat ileum.

MATERIAL AND METHODS

The powder of the roots of C. sieberiana was treated in a soxhlet with ethanol at 90 degrees. After dry evaporation, the extract was dissolved into water before successive treatments with ethyl acetate and butanol. Ethyl acetate, butanolic and aqueous residual fractions as well as the ethanolic total extract were tested on isolated rat ileum.

RESULTS

The mean of inhibition Percentage (MIP) of the basal tonus of rat ileum after the total ethanolic extract (75 microg/ml) treatment was 50.51 +/- 10.18% (p < 0.05, n=5). Ethyl acetate and butanolic fractions were significantly more active on the ileal basal tonus to the one of total ethanolic extract. At 37.5 microg/ml, it decreased the ileal basal tonus with MIP respectively to 70.46 +/- 5.18% and 60.61 +/- 1.5% (p < 0.05, n=5). In contrast, the residual aqueous fraction was not active at all. After intestine precontracted with acetylcholine, the total ethanolic extract (MIP=52 +/- 20.49%) as well as the butanolic (MIP = 73 +/- 6.09%) and the ethyl acetate (MIP = 71 +/- 4.07 %) (p < 0.05, n=5) fractions induced a significant decrease of spasms (p < 0.05) (n=5).

CONCLUSION

the butanolic and ethyl acetate fractions of the roots of C. sieberiana were more potent than the total ethanolic extract to induce myorelaxant a nd antispasmodic activity on isolated rat ileum. This study provides a pharmacological basis for a rational use of the roots of C. sieberiana in traditional medicine to treat gastro-intestinal disorders.

Display of polarization information by coherently moving dots

It is known that human eyes are effectively polarization-blind. Therefore, in order to display the polarization information in an image, one may require exhibiting such information using other visual cues that are compatible with the human visual system and can be easily detectable by a human observer. Here, we present a technique for displaying polarization information in an image using coherently moving dots that are superimposed on the image. Our examples show that this technique would allow the image segments with polarization signals to "pop out" easily, which will lead to better target feature detection and visibility enhancement.

Hepatic over-expression of peroxisome proliferator activated receptor gamma2 in the ob/ob mouse model of non-insulin dependent diabetes mellitus

Studies of the molecular basis of insulin resistance have focused on the peroxisome proliferator activated receptor gamma (PPARgamma, gamma1 and gamma2). The aim of this study was to determine whether the insulin resistance in liver of diabetic animals is associated with abnormal expression of these receptors. PPARgamma mRNA and protein expression levels were quantified in liver of 9-week-old male ob/ob mice as a model of diabetes and compared to age- and gender-matched wild type control animals of the same genetic background. Semi-quantitative reverse transcription-polymerase chain reaction, using 18S rRNA as an internal standard, indicated that PPARgamma2 mRNA was significantly upregulated in ob/ob liver vs. that in wild type mice. Western blotting revealed greater immunoreactivity of PPARgamma2 in liver from ob/ob mice relative to that in wild type mice. An index of insulin resistance (product of serum glucose and insulin concentration) was correlated with liver PPARgamma2 mRNA expression (r = 0.776; p < 0.001). The findings that liver PPARgamma2 expression is (1) significantly elevated in the ob/ob model of diabetes and (2) positively associated with an index of insulin resistance, suggests a possible compensatory response through which type II diabetic and obese organisms strive to maintain insulin sensitivity of the liver.

Salt sensitivity in genetically hypertensive rats of the Lyon strain

BACKGROUND

Genetically hypertensive (LH) rats of the Lyon strain exhibit a blunted pressure-natriuresis function when compared, in acute conditions, with their normotensive (LN) and low blood pressure (LL) controls. The present work was aimed to determine whether LH rats were salt sensitive in chronic conditions. In addition, a protocol was developed to determine the renal function curve in freely moving rats.

METHODS

Fourteen-week-old rats either untreated or orally treated since weaning with perindopril (3 mg/kg/24 h), an angiotensin-converting enzyme inhibitor, or with valsartan (15 mg/kg/24 h), an angiotensin II subtype 1 receptor antagonist, so as to eliminate the influence of endogenous changes in angiotensin formation were used. Blood pressure (BP) and urinary sodium excretion were measured before, during an oral salt load (2% NaCl in drinking water), and during a two-week aldosterone infusion (50 microg/kg/24 h subcutaneously).

RESULTS

NaCl induced a greater BP increase in untreated LH rats than in LN and LL controls. Perindopril normalized the BP of LH rats but not its elevation during a salt load. Aldosterone slightly increased BP in LH and LL rats either untreated or treated with valsartan. Finally, the combination of telemetric BP measurement with 24-hour urine collection when salt was added to drinking water allowed accurate determination of the slope of the chronic renal function curve in freely moving rats.

CONCLUSION

The present work demonstrates that LH rats are salt sensitive. This characteristic manifests despite the lack of an active renin-angiotensin system and is not explained by a hypersensitivity to aldosterone.

Reduced oxidative-stress response in red blood cells from p45NFE2-deficient mice

p45NF-E2 is a member of the cap 'n' collar (CNC)-basic leucine zipper family of transcriptional activators that is expressed at high levels in various types of blood cells. Mice deficient in p45NF-E2 that were generated by gene targeting have high mortality from bleeding resulting from severe thrombocytopenia. Surviving p45nf-e2(-/-) adults have mild anemia characterized by hypochromic red blood cells (RBCs), reticulocytosis, and splenomegaly. Erythroid abnormalities in p45nf-e2(-/-) animals were previously attributed to stress erythropoiesis caused by chronic bleeding and, possibly, ineffective erythropoiesis. Previous studies suggested that CNC factors might play essential roles in regulating expression of genes that protect cells against oxidative stress. In this study, we found that p45NF-E2-deficient RBCs have increased levels of reactive oxygen species and an increased susceptibility to oxidative-stress-induced damage. Deformability of p45NF-E2-deficient RBCs was markedly reduced with oxidative stress, and mutant cells had a reduced life span. One possible reason for increased sensitivity to oxidative stress is that catalase levels were reduced in mutant RBCs. These findings suggest a role for p45NF-E2 in the oxidative-stress response in RBCs and indicate that p45NF-E2 deficiency contributes to the anemia in p45nf-e2(-/-) mice. (Blood. 2001;97:2151-2158)

Stress-induced, tissue-specific enrichment of hsp70 mRNA accumulation in Xenopus laevis embryos

In this study, we have employed whole-mount, in situ hybridization to study the spatial pattern of hsc70 and hsp70 mRNA accumulation in normal and heat shocked embryos during Xenopus laevis development. Our findings revealed that hsc70 mRNA was constitutively present in a global fashion throughout the embryo and was not heat inducible. Accumulation of hsp70 mRNA, however, was detected only in heat shocked embryos. Furthermore, hsp70 mRNA accumulation was enriched in a tissue-specific manner in X. laevis tailbud embryos within 15 minutes of a 33 degrees C heat shock. Abundant levels of heat shock-induced hsp70 mRNA were detected in the head region, including the lens placode, the cement gland, and in the somitic region and proctodeum. Preferential heat-induced accumulation of hsp70 mRNA was first detected at a heat shock temperature of 30 degrees C. Placement of embryos at 22 degrees C after a 1-hour, 33 degrees C heat shock resulted in decreased hsp70 mRNA with time, but the message persisted in selected tissues, including the lens placode and somites. Treatment of tailbud embryos with either sodium arsenite or zinc chloride induced a tissue-specific enrichment of hsp70 mRNA in the lens placode and somitic region. These studies reveal the complex nature of the heat shock response in different embryonic tissues and suggest the presence of regulatory mechanisms that lead to a stressor-induced, tissue-specific enrichment of hsp70 mRNA.

Renin-angiotensin system in two genetically normotensive strains of Lyon rats

Compared to the Lyon normotensive (LN) controls, adult Lyon hypertensive rats (LH) exhibit a renin-angiotensin system (RAS) dependent hypertension despite a low renin secretion. This discrepancy could be explained by the elevated slow pressor response to angiotensin II (AII) found in LH rats compared to LN controls. To evaluate more precisely the pathophysiological importance of this increased response, the present work aimed at determining whether the characteristics of the RAS were identical in LN and low blood pressure (LL) rats, the other normotensive control strain simultaneously selected with LH rats. Plasma and kidney renin and prorenin were measured in 11-week-old LN and LL rats. Aortic blood pressure (BP) was recorded at 15 weeks of age in freely moving rats of both strains either untreated or having received an angiotensin converting enzyme inhibitor, perindopril (3 mg/kg/day orally) since the age of 3 weeks. Acute dose-response curves were constructed for AII and norepinephrine (NE). The long-term pressor effects of AII (200 ng/kg/ min) and NE (1000 ng/kg/min) were measured after chronic infusions in perindopril-treated LN and LL rats. LN and LL rats exhibited similar mean BP level before (114 +/- 2 and 117 +/- 2 mm Hg, respectively) and after perindopril treatment (91 +/-3 and 93 +/- 1 mm Hg, respectively). Plasma and kidney renin and prorenin were decreased in LL rats. In acute conditions, LL rats exhibited an unspecific hypersensitivity to AII and NE. Chronically given AII exerted a greater pressor effect in LL than in LN rats after 4 weeks (113 +/- 3 v 97 +/- 5 mm Hg in LL and LN rats respectively, P < .05) and, even more, after 8 weeks of infusion (144 +/- 9 v 124 +/- 4 mm Hg in LL and LN rats respectively, P < .05). The NE was devoid of chronic pressor effects. In conclusion, 1) the increased slow pressor response to AII may not be a critical pathogenetic factor in the development of hypertension, as it also exists in normotensive LL rats; 2) LN and LL rats have the same normal BP despite marked differences in their RAS, thus suggesting that there could be several forms of normotension as known for hypertension; and 3) the simple comparison between one genetically hypertensive strain and one single normotensive control strain does not allow one to conclude that a phenotypic difference is of pathophysiological significance.

11beta-hydroxysteroid dehydrogenase and corticosteroid action in lyon hypertensive rats

Adrenocorticosteroid activity in Lyon hypertensive (LH) and low blood pressure (LL) rat strains differ in several respects. Abnormal activity of 11beta-hydroxysteroid dehydrogenase enzymes (11beta-HSD1 and 11beta-HSD2), which interconvert corticosterone and inactive 11-dehydrocorticosterone, might contribute to the LH phenotype by regulating corticosteroid hormone access to receptors. 11beta-HSD2 (expressed in kidney but not liver) prevents endogenous glucocorticoids from binding to mineralocorticoid receptors. 11beta-HSD1 (expressed in liver and kidney) favors active glucocorticoid formation from 11-dehydrocorticosterone. 11beta-HSD properties in LH and LL have been compared by several approaches: (1) 11betaHSD activities have been measured in vitro as corticosterone dehydrogenation and in vivo as interconversion of injected cortisol and cortisone; (2) the effects of cortisol and cortisone on urine electrolytes and volume have been measured; and (3) 11beta-HSD mRNA expression has been measured by in situ hybridization. 11beta-HSD2 enzyme activities in LH and LL rats were similar and urinary cortisone:cortisol ratios were not different after cortisol injection. Cortisol caused a natriuresis and kaliuresis in both strains, with a slightly reduced response in LH rats. Renal 11beta-HSD2 mRNA expression was slightly lower in LH rats. 11beta-HSD1 was less active in LH than LL rats: enzyme activities were lower in tissue extracts; urinary cortisone:cortisol was lower in LL rats after cortisone injections; cortisone increased urine volume in LL but not LH rats; and mRNA levels tended to be lower in LH tissues. We conclude that 11beta-HSD1 is impaired in LH rats. The LH phenotype of heavier adrenals, raised corticosterone, and reduced thymus weight is similar to that described for 11beta-HSD1 knockout mice.

Restoration of lymphoid populations in a murine model of X-linked severe combined immunodeficiency by a gene-therapy approach

X-linked severe combined immunodeficiency (XSCID) is a life-threatening syndrome in which both cellular and humoral immunity are profoundly compromised. This disease results from mutations in the IL2RG gene, which encodes the common cytokine receptor gamma chain, gamma(c). Previously, we generated gamma(c)-deficient mice as a murine model of XSCID. We have now used lethally irradiated gamma(c)-deficient mice to evaluate a gene therapeutic approach for treatment of this disease. Transfer of the human gamma(c) gene to repopulating hematopoietic stem cells using an ecotropic retrovirus resulted in an increase in T cells, B cells, natural killer (NK) cells, and intestinal intraepithelial lymphocytes, as well as normalization of the CD4:CD8 T-cell ratio and of serum Ig levels. In addition, the restored cells could proliferate in response to interleukin-2 (IL-2). Thus, our results provide added support that gene therapy is a feasible therapeutic strategy for XSCID. Moreover, because we used a vector directing expression of human gamma(c) to correct a defect in gamma(c)-deficient mice, these data also indicate that human gamma(c) can cooperate with the distinctive cytokine receptor chains such as IL-2Rbeta and IL-7Ralpha to mediate responses to murine cytokines in vivo.

Rift valley fever surveillance in the lower Senegal river basin: update 10 years after the epidemic

After the Rift valley fever (RVF) epidemic of 1987 in the Senegal River Basin, RVF surveillance based on serosurveys has been conducted for 10 years. Serum samples were obtained from 1336 persons and from sheep and goats in selected areas, and these were tested for IgG/IgM RVF antibodies by ELISA. After a period of regular decrease in RVF prevalence in domestic animals until 1993, an epizootic was observed in all herds in 1994-95 with increases in IgM levels and abortions. During the same period, no human cases or RVF IgM were detected. The RVF IgG prevalence significantly correlated with date of birth: children born after 1987 have a low prevalence (5%) in clear contrast to the older population (25.3%) in Podor district. A retrospective analysis of rainfall and RVF prevalence in small domestic animals over the last 10 years showed that the re-emergence correlated with heavy rainfall. A general analysis of the risk of re-emergence and the efficiency of this RVF surveillance system are presented.

Effects of fetal and neonatal renin-angiotensin system blockade in Lyon hypertensive rats

It has been shown that a brief period of angiotensin-converting enzyme (ACE) inhibition in growing spontaneously hypertensive rats (SHRs) induces long-term decrease of the blood pressure (BP) level. This study assessed whether persistent effects of ACE inhibition could be disclosed in Lyon genetically hypertensive (LH) rats treated from conception to age 3 weeks. ACE inhibition was obtained with captopril (100 mg/kg/24 h in the drinking water of the breeders) because this compound crosses the placental barrier. For each of the six treated pairs, the first litter was discarded, the second served as control, whereas the third and the fourth were obtained during captopril treatment. Six other pairs remained untreated. Aortic BP was beat-to-beat recorded in freely moving 14-week-old rats. It was observed that captopril reduced the number of newborns (42 in the second vs. 17 rats in the third litter of six LH pairs). BP and left ventricle weight did not differ between control and treated animals. It is concluded that, unlike SHRs, in LH rats, ACE inhibition is devoid of persistent effects on BP after cessation of the treatment.

The subtype 2 of angiotensin II receptors and pressure-natriuresis in adult rat kidneys

The present work examined the effects of the subtype 2 of angiotensin II (AT2) receptors on the pressure-natriuresis using a new peptide agonist, and the possible involvement of cyclic guanosine 3', 5' monophosphate (cyclic GMP) in these effects. In adult anaesthetized rats (Inactin, 100 mg kg(-1), i.p.) deprived of endogenous angiotensin II by angiotensin converting enzyme inhibition (quinapril, 10 mg kg(-1), i.v.), T2-(Ang II 4-8)2 (TA), a highly specific AT2 receptor agonist (5, 10 and 30 microg kg(-1) min(-1), i.v.) or its solvent was infused in four groups. Renal functions were studied at renal perfusion pressures (RPP) of 90, 110 and 130 mmHg and urinary cyclic GMP excretion when RPP was at 130 mmHg. The effects of TA (10 microg kg(-1) min(-1)) were reassessed in animals pretreated with PD 123319 (PD, 50 microg kg(-1) min(-1), i.v.), an AT2 receptor antagonist and the action of the same dose of PD alone was also determined. Increases in RPP from 90 to 130 mmHg did not change renal blood flow (RBF) but induced 8 and 15 fold increases in urinary flow and sodium excretion respectively. The 5 microg kg(-1) min(-1) dose of TA was devoid of action. The 10 and 30 microg kg(-1) min(-1) doses did not alter total RBF and glomerular filtration rate, but blunted pressure-diuresis and natriuresis relationships. These effects were abolished by PD. TA decreased urinary cyclic GMP excretion. After pretreatment with PD, this decrease was reversed to an increase which was also observed in animals receiving PD alone. In conclusion, renal AT2 receptors oppose the sodium and water excretion induced by acute increases in blood pressure and this action cannot be directly explained by changes in cyclic GMP.

Mechanisms of spontaneous baroreflex impairment in lyon hypertensive rats

This experiment aimed at 1) comparing the spontaneous baroreflex sensitivity (SBRS) in Lyon genetically hypertensive (LH), normotensive (LN), and low blood pressure (LL) rats and 2) assessing some aspects of the mechanisms of its impairment in LH rats. Baroreflex was studied in control animals after an early chronic converting enzyme inhibition with perindopril and after a 4-wk infusion of ANG II in perindopril-treated rats. The SBRS was determined with a previously validated method, using statistical dependence between blood pressure (BP) and heart rate values recorded in freely moving animals. LH rats exhibited high BP, cardiac hypertrophy, and decreased SBRS (LH, 1.3 +/- 0.2; LN, 2.5 +/- 0.4; LL, 2.2 +/- 0.4 beats . min-1 . mmHg-1). Perindopril prevented the development of hypertension and cardiac hypertrophy and normalized SBRS. BP rose in LH and LL rats after ANG II infusion, but only LH rats, which developed a cardiac hypertrophy, had an impaired SBRS (LH, 1.1 +/- 0.2; LN, 2.5 +/- 0.2; LL, 2.8 +/- 0.3 beats . min-1 . mmHg-1). This impairment was partially reversed by an acute ANG II blockade with losartan. These results demonstrate that high BP does not account for the decreased SBRS in LH rats. SBRS impairment could result either from cardiac hypertrophy or from the direct effect of ANG II on the baroreflex loop.