Cardiovascular Comorbidities Do Not Impact Prostate Artery Embolisation (PAE) Outcomes: Retrospective Analysis of the National UK-ROPE Registry

PURPOSE

Prostate artery embolisation (PAE) is a key treatment for the management of symptomatic benign prostatic hyperplasia (BPH). Common cardiovascular risk factors might be associated with suboptimal outcomes and thus influence patient treatment selection. The aim of the study was to evaluate whether cardiovascular comorbidities affect PAE outcomes.

METHODS

Retrospective subset analysis of the UK Registry of Prostate Artery Embolisation (UK-ROPE) database was performed with patients who had a full documented past medical histories including hypertension, diabetes, coronary artery disease (CAD), diabetes and smoking status as well as international prostate symptom score (IPSS) at baseline and at 12 months. Multiple regression was performed to assess for any significant predictors.

RESULTS

Comorbidity data were available for 100/216 patients (mean age 65.8 ± 6.4 years), baseline IPSS 20.9 ± 7.0). Regression analysis revealed that the presence of hypertension (53.7% IPSS reduction vs. absence 51.4%, p = 0.94), diabetes (52.6% vs. absence 52.1%, p = 0.6), CAD (59.2% vs. absence 51.4%, p = 0.95), no comorbidities (49.8% vs. any comorbidity present 55.3%, p = 0.66), smoking status (non-smoker, 52.6%, current smoker, 61.5%, ex-smoker, 49.8%, p > 0.05), age (p = 0.52) and baseline Qmax (p = 0.41) did not significantly impact IPSS reduction at 12 months post-PAE. Baseline prostate volume significantly influenced IPSS reduction (≥ 80 cc prostates, 58.9% vs. < 80 cc prostates 43.2%, p < 0.05).

CONCLUSION

The presence of cardiovascular comorbidities/smoking history does not appear to significantly impact PAE symptom score outcomes at 12 months post procedure. Our findings suggest that if the prostatic artery can be accessed, then clinical success is comparable to those without cardiovascular comorbidities.

The Effect of Protective Coil Embolization of Penile Anastomoses during Prostatic Artery Embolization on Erectile Function: A Propensity-Matched Analysis

PURPOSE

To explore whether coil embolization of penile collateral arteries to prevent nontarget embolization during prostatic artery embolization (PAE) negatively affects erectile function.

MATERIALS AND METHODS

Retrospective analysis was performed on a prospectively maintained multicenter PAE database on all patients with benign prostatic hyperplasia (January 2014 to July 2016). International Index of Erectile Function (IIEF-5) scores were collected at baseline and within 12 months after the procedure. A logistic regression and nearest neighbor propensity-matched analysis (matched for age, baseline IIEF-5 scores, and use of 5α-reductase inhibitors) and paired t test were used to evaluate for differential impact on IIEF-5 scores between the group of patients who underwent (unilateral) penile collateral coil embolization and a matched control group of patients who did not.

RESULTS

Of a total of 216 patients, 26 underwent coil protection of an accessory pudendal vessel/penile collateral. After exclusions, 22 propensity-matched pairs were identified. The mean IIEF-5 score at baseline for the coil-embolized group was 14.8 ± 8.3 (out of a possible score of 30) and that for the matched control group was 14.0 ± 7.8. At the 12-month follow-up after the procedure, the mean follow-up IIEF-5 score was 15.5 ± 8.0 for the coil-embolized group and 14.2 ± 8.2 for the matched control group. The change in IIEF-5 scores after PAE was not significantly different between the 2 groups (0.66 ± 3.8 vs 0.20 ± 2.0; P = .64; 95% CI, -1.53 to 2.44).

CONCLUSIONS

When penile collateral arteries were identified, protective coil embolization of penile collateral/accessory pudendal vessels during PAE was unlikely to affect erectile function negatively.

The impact on Anti-Mullerian Hormone (AMH), uterine fibroid size and uterine artery patency following Uterine Fibroid Embolization (UFE) with a resorbable embolic agent

The effect of Uterine Fibroid Embolization on fertility and ovarian reserve remains uncertain. We assessed the impact of a new resorbable, spherical particle (Gelbead) on concentration of Anti-Mullerian (AMH) hormone, fibroid volume and uterine artery patency. This prospective cohort study recruited consecutive patients from July 2017 to June 2018. Serum AMH, fibroid and uterine volume, UFS-QOL (uterine fibroid score-quality of life) scores were measured prior to and at 1 month and/or 3 months post embolization. Twenty-four participants were enrolled (median age 44 years, uterine volume 484 cm³, initial dominant fibroid volume 167 cm³). One patient was lost to follow-up. AMH (median ± SD) immediately prior to embolization was 3.2 ± 13.7 pmol/L. At 1-month postembolization, AMH was 4.1 ± 8.6 pmol/L and at 3 months 4.4 ± 8.6 pmol/L. We found no significant difference in AMH levels between baseline and at 1 month (p = 0.58) or baseline and 3 months (p = 0.17). The median dominant uterine fibroid volume decreased (167 to 64 cm³, p < 0.001). At 3 months post-embolization, 17/23 patients had patent uterine arteries bilaterally (73.9%). UFE with Gel-bead did not significantly affect AMH at 3 months post embolization, whilst maintaining a high rate of uterine artery patency.

Comprehensive Review on Current Controversies and Debate in Prostate Artery Embolization

Prostate artery embolization is emerging as one of the most effective therapies amidst a new era of mini- mally invasive benign prostate hyperplasia treatment and technology. However, several current controver- sies remain unanswered which could impact the widespread adoption of this novel and unique transarterial(rather than transurethral) intervention. This is reflected in the differences between the UK (NICE), European (EAU), and American (AUA) guidelines, the latter of which only recommends the use of prostate arteryembolization in a clinical trial setting. The main issues include questions over the duration of symptom response, cost-effectiveness, mechanism of action, patient selection, and other procedural technical consid- erations. These factors are the most pressing faced by proponents of prostate artery embolization, and we seek to highlight why their resolution is important to ensure men with benign prostate hyperplasia seeking a minimally invasive solution are optimally informed and most effectively managed.

10-year experience of Paediatric varicocele embolization in a tertiary centre with long-term follow-up

INTRODUCTION

Paediatric varicocele embolization has many benefits over surgical ligation, but lacks published long-term data. We investigated technical and clinical outcomes in this under reported patient group.

OBJECTIVE

To evaluate technical success, complications and recurrence rates following varicocele embolization in paediatric patients.

MATERIALS AND METHODS

A single-centre retrospective review of procedural data and electronic notes of consecutive patients referred for varicocele embolization over a 10-year period was performed (February 2010-March 2020). The primary outcomes were technical success and clinical efficacy (lack of symptom recurrence). Secondary outcomes included complications, testicular vein size reduction and procedural parameters including radiation exposure. Chi-square analysis was used to identify predictors of clinical success. Follow-up involved outpatient clinical assessment and telephone interview.

RESULTS

40 patients (median age 15) were referred for left-sided symptomatic varicocele. Technical embolization success was achieved in 36/40 patients (90%), with 4 procedures abandoned (inaccessible vein). Embolization technique was platinum-based coils ± sclerosant. There were no immediate or long-term procedural complications. 32/36 patients completed short term follow-up at a median interval of 2.8 months. 30/32 (93.78%) experienced early clinical success. We found a significant reduction in peritesticular vein size following embolization (pre-3.70 vs post-2.56 mm, p = 0.00017) and a significant relationship between varicocele grade and early clinical success (χ2 = 4.2, p = 0.04), but not pre-treatment peritesticular vein size (χ2 = 0.02, p = 0.88). 33/36 patients completed long-term follow-up (median 4.2 years, range 0.36-9.9 years) producing a late clinical success rate of 93.9% (31/33). No post procedural complications including hydroceles were identified.

DISCUSSION

This study demonstrates technical success, matching rates described in adult patients which is reassuring and in support of embolization in the younger patient cohort. More importantly, the overall clinical success rate is comparable with previous embolization studies. Reassuringly, all symptom recurrences occurred early in follow-up, and there is a cogent argument for a single follow-up appointment at this juncture. Our long-term average follow-up duration, primarily gained via telephone interview, exceeds other studies. Although our study has the longest follow-up for varicocele embolization in children, it is limited by a few patients being lost to early and long-term follow-up. This is a recognised issue faced by studies attempting to follow-up benign conditions with a high clinical success rate.

CONCLUSION

Paediatric varicocele embolization is a successful alternative to surgical ligation, with no complications and good clinical outcomes over a long-term follow-up.

Comprehensive Imaging Characterization of Colorectal Liver Metastases

Colorectal liver metastases (CRLM) have heterogenous histopathological and immunohistochemical phenotypes, which are associated with variable responses to treatment and outcomes. However, this information is usually only available after resection, and therefore of limited value in treatment planning. Improved techniques for in vivo disease assessment, which can characterise the variable tumour biology, would support further personalization of management strategies. Advanced imaging of CRLM including multiparametric MRI and functional imaging techniques have the potential to provide clinically-actionable phenotypic characterisation. This includes assessment of the tumour-liver interface, internal tumour components and treatment response. Advanced analysis techniques, including radiomics and machine learning now have a growing role in assessment of imaging, providing high-dimensional imaging feature extraction which can be linked to clinical relevant tumour phenotypes, such as a the Consensus Molecular Subtypes (CMS). In this review, we outline how imaging techniques could reproducibly characterize the histopathological features of CRLM, with several matched imaging and histology examples to illustrate these features, and discuss the oncological relevance of these features. Finally, we discuss the future challenges and opportunities of CRLM imaging, with a focus on the potential value of advanced analytics including radiomics and artificial intelligence, to help inform future research in this rapidly moving field.

1-year cost-utility analysis of prostate artery embolization (PAE) versus transurethral resection of the prostate (TURP) in benign prostatic hyperplasia (BPH)

Objective

To determine whether prostate artery embolization (PAE) is a cost-effective alternative to transurethral resection of the prostate (TURP) in the management of benign prostate hyperplasia (BPH) after 1-year follow-up.

Design, setting and main outcome measures

A retrospective cost-utility analysis over a 12-month time period was conducted to compare the two interventions from a National Health Service perspective. Effectiveness was measured as quality-adjusted life years (QALYs) derived from data collected during the observational UK Register of Prostate Embolisation (UK-ROPE) Study. Costs for both PAE and TURP were derived from University Hospital Southampton, a tertiary referral centre for BPH and the largest contributor to the UK-ROPE. An incremental cost-effectiveness ratio (ICER) was derived from cost and QALY values associated with both interventions to assess the cost-effectiveness of PAE versus TURP. Further sensitivity analyses involved a decision tree model to account for the impact of patient-reported complications on the cost-effectiveness of the interventions.

Results

The mean patient age for TURP (n=31) and PAE (n=133) was 69 and 65.6 years, respectively. In comparison to TURP, PAE was cheaper due to shorter patient stays and the lack of necessity for an operating theatre. Analysis revealed an ICER of £64 798.10 saved per QALY lost when comparing PAE to TURP after 1-year follow-up.

Conclusion

Our findings suggest that PAE is initially a cost-effective alternative to TURP for the management of BPH after 1-year follow-up. Due to a higher reintervention rate in the PAE group, this benefit may be lost in subsequent years.

Trial registration number

NCT02434575.

Prostatic Artery Embolization (PAE) and Transurethral Resection of the Prostate (TURP) have a Differential Impact on Lower Urinary Tract Symptoms (LUTS): Retrospective Analysis of the Multicentre UK-ROPE (UK Register of Prostate Embolization) Study

PURPOSE

To compare the relative IPSS (International Prostate Symptom Score) improvement in storage and voiding symptoms between prostatic artery embolization (PAE) and transurethral resection of the prostate (TURP).

METHOD

Retrospective analysis of the UK-ROPE (UK Register of Prostate Embolization) multicentre database was conducted with inclusion of all patients with full IPSS questionnaire score data. The voiding and storage subscore improvement was compared between interventions. Student's t-test (paired and unpaired) and ANOVA (Analysis of variance) were used to identify significant differences between the groups.

RESULTS

146 patients (121 PAE, 25 TURP) were included in the analysis. Storage symptoms were more frequently the most severe symptom ('storage' in 75 patients vs 'voiding' in 17 patients). Between groups, no significant difference was seen in raw storage subscore improvement (TURP 4.9 vs PAE 4.2; p = 0.34) or voiding subscore improvement (TURP 8.4 vs PAE 6.7; p = 0.1). ANOVA demonstrated a greater proportionate reduction (relative to total IPSS) towards voiding symptoms in the TURP group (27.3% TURP vs 9.9% PAE, p = 0.001).

CONCLUSION

Although both TURP and PAE improve voiding symptoms more than storage, a significantly larger proportion of total symptom reduction is due to voiding in the TURP cohort, with PAE providing a more balanced improvement between voiding and storage.

A retrospective cohort study comparing a novel, spherical, resorbable particle against five established embolic agents for uterine fibroid embolisation

AIM

To evaluate the effectiveness of a novel, resorbable, spherical embolic agent compared with other established agents, by studying percentage fibroid infarction (the best indicator of long-term symptom improvement) in patients undergoing uterine fibroid embolisation (UFE).

MATERIALS AND METHODS

This retrospective cohort study examined six different embolic agents used for fibroid embolisation, including a new gelatin-based, fully resorbable, spherical agent. The primary effectiveness outcomes were magnetic resonance imaging (MRI)-determined dominant fibroid infarct percentage (DF%) and all fibroid percentage infarct (AF%) at 3 months post-embolisation. MRI-determined uterine artery patency rate was the secondary outcome. Chi-squared test (χ²), relative risk (RR) calculation (primary outcomes), and analysis of variance (ANOVA) (secondary outcome) were the statistical tests employed.

RESULTS

One hundred and twenty patients were treated with six embolic agents (20 consecutive patients per group, overall mean age 44.8±6.4, initial uterine volume 570±472 ml, dominant fibroid volume 249±324 ml). Fibroid infarctrates were similar between the cohorts with no significant difference between the new gelatin-based resorbable particle and other embolics in either DF% (χ²=3.92, p=0.56) or AF% (χ²=2.83, p=0.73). Complete DF% RR=1.07 (0.90-1.27) and AF% RR=1.09 (0.85-1.41) suggest non-inferiority of the resorbable particle (d=0.67, p<0.05). A favourable uterine artery patency rate was demonstrated for the resorbable particle compared with gelatin slurry (82.5% versus 27.5%, p<0.001 after Bonferroni adjustment).

CONCLUSIONS

This new gelatin-based, fully resorbable particle is an effective embolic agent for fibroid embolisation and achieves an infarct rate non-inferior to established embolics.

Does Prostate Artery Embolization (PAE) Improve Voiding Symptoms, Storage Symptoms, or Both?

INTRODUCTION

Many studies have looked at global changes in the International Prostate Symptom Score (IPSS) following PAE; however, no studies have examined the breakdown between storage and voiding symptoms. We aimed to explore the extent to which PAE improves storage symptoms in relation to voiding symptoms.

METHOD

This single-center, prospective cohort study recruited consecutive patients undergoing PAE from June 2012 to June 2016. The IPSS breakdown was recorded pre-PAE, at 3 months and 12 months post-PAE. Planned statistical analysis included the paired t test.

RESULTS

A total of 43 patients were recruited (mean age 64.72 ± 6.27, prostate volume 88.65 ± 37.23 cm³, IPSS 23.02 ± 5.84, QoL 4.98 ± 1.01, PSA 4.2 ± 2.8). Storage symptoms were more frequently the most severe symptom (58.1%). Voiding score (13.35-5.39, p < 0.001) and storage score (9.67-5.08, p < 0.001) both improved; however, voiding improved to a greater extent (1.9 vs. 1.5 mean per question, p = 0.023). PAE was most consistent when improving storage symptoms ('Urgency' improved in 86% patients, 'Frequency' and 'Nocturia' 77%).

CONCLUSION

Storage symptoms are a significant problem for patients with benign prostatic obstruction. PAE is an effective treatment for both storage and voiding symptoms. More research is needed to evaluate how this compares with surgical techniques.

Prostate artery embolization: a new, minimally invasive treatment for lower urinary tract symptoms secondary to prostate enlargement

Prostate artery embolization (PAE) is emerging as a safe and efficacious treatment which approaches benign prostatic obstruction (BPO) from a unique perspective. This brings with it distinct advantages and solutions, which we discuss along with cost, evidence, complications and disadvantages.

Drugs in pregnancy. Renal disease

The management of pregnant women with renal impairment presents a major challenge to obstetricians, nephrologists, and ultimately paediatricians. As renal failure progresses there is an increase in both maternal and fetal complications. Often these women have intercurrent medical conditions and, prior to conception, are receiving a broad range of prescribed medications. A successful obstetric outcome relies upon careful pre-pregnancy counselling and planning, obsessive monitoring during pregnancy, and close liaison between different specialist teams. Experience is mounting in the management of pregnant transplant recipients, but the introduction of newer immunosuppressive agents which have great promise in prolonging graft survival present new problems for those recipients of a kidney transplant who are planning to conceive. We review drug prescription for pregnant patients with renal impairment, end-stage renal failure, or a kidney transplant.

The reversed Kenner linker: a new safety-catch linker for the preparation of N-alkyl sulfonamides

A new strategy for the solid-phase synthesis of sulfonamides is described. The Kenner safety-catch strategy has been modified such that the carboxylic acid component remains attached to the solid support while the sulfonamide portion is released into solution. An initial demonstration of the scope of this strategy is presented, along with an analysis of the cleavage characteristics and extension to more elaborate products via Suzuki reaction and thiazolidinone synthesis. Reaction: see text.

Honest assessments of automatic learning algorithm performance

OBJECTIVE

To compare methods of evaluating probabilistic predictors in systems that learn from examples.

STUDY DESIGN

The performance of four automatic learning algorithms, representing current machine learning technology, were assessed using four methodologies in the task of separating normal squamous intermediate cervical cells from all other segmented objects in digital images. Two of the methodologies were carefully constructed to model sources of variation associated with the choice of training and test sets. These assessments were statistically compared with assessments using both standard and a modified version of cross-validation.

RESULTS

The investigation illustrates the tradeoffs involved in obtaining statistical rigor as compared with the cost of collecting data. While cross-validation makes frugal use of data, it can produce misleading assessments of algorithm performance in terms of both bias and variance. The modified version produces more reliable assessments but in some cases may also be misleading.

CONCLUSION

We suggest that users of learning algorithms should exercise judicious care in evaluating learning algorithm performance in order to avoid unnecessary bias and large variance in their assessments.

Adenosine concentrations in the interstitium of resting and contracting human skeletal muscle

BACKGROUND

Adenosine has been proposed to be a locally produced regulator of blood flow in skeletal muscle. However, the fundamental questions of to what extent adenosine is formed in skeletal muscle tissue of humans, whether it is present in the interstitium, and where it exerts its vasodilatory effect remain unanswered.

METHODS AND RESULTS

The interstitial adenosine concentration was determined in the vastus lateralis muscle of healthy humans via dialysis probes inserted in the muscle. The probes were perfused with buffer, and the dialysate samples were collected at rest and during graded knee extensor exercise. At rest, the interstitial concentration of adenosine was 220+/-100 nmol/L and femoral arterial blood flow (FaBF) was 0.19+/-0.02 L/min. When the subjects exercised lightly, at a work rate of 10 W, there was a markedly higher (1140+/-540 nmol/L; P<0.05) interstitial adenosine concentration and a higher FaBF (2.22+/-0.18 L/min; P<0.05) compared with at rest. When exercise was performed at 20, 30, 40, or 50 W, the concentration of adenosine was moderately greater for each increment, as was the level of leg blood flow. The interstitial concentrations of ATP, ADP, and AMP increased from rest (0.13+/-0.03, 0.07+/-0.03, and 0.07+/-0.02 micromol/L, respectively) to exercise (10 W; 2.00+/-1.32, 2.08+/-1.23, and 1.65+/-0.50 micromol/L, respectively; P<0.05).

CONCLUSIONS

The present study provides, for the first time, interstitial adenosine concentrations in human skeletal muscle and demonstrates that adenosine and its precursors increase in the exercising muscle interstitium, at a rate associated with intensity of muscle contraction and the magnitude of muscle blood flow.

Encoded combinatorial chemistry: synthesis and screening of a library of highly functionalized pyrrolidines

The application of a new encoding technology for drug discovery is described. A combinatorial library of mercaptoacyl pyrrolidines has been prepared on a beaded polymeric support. Each polymer bead carries one library constituent in association with an oligomeric "tag," the structure of which is a record of the specific reagents from which that library member was prepared. After the ligands were solubilized, an array of such beads was screened for angiotensin-converting enzyme inhibitory activity, and the structures of active pyrrolidines were deduced by analysis of the associated tags at sub-picomole levels. Several extremely potent enzyme inhibitors were identified, many from multiple beads. The most potent inhibitor was found to have a Ki of 160 pM, approximately 3-fold more active than captopril in the same assay. Direct comparison with iterative deconvolution shows that the encoded screening strategy is a much more efficient means for extracting information from such compound collections, producing more data on a larger number of active structures.

Substitution of D-Trp32 in NPY destabilizes the binding transition state to the Y1 receptor site in SK-N-MC cell membranes

The retention rate of the spin label 3-isothiocyanto methyl-2,2,5,5-tetramethyl-1-pyrrolidinyl oxyl spin label (proxyl) attached to the porcine N-acetyl-NPY peptide and the porcine N-acetyl-D-Trp32-NPY peptide at Lys4 was investigated using SK-N-MC neuroblastoma cell membranes containing the Y1 receptor. The release rate of the spin labeled peptides was monitored by electron spin resonance and the KD was determined by a direct radiolabeled NPY displacement binding assay. The analyses show that for the porcine [Ac-Tyr1N epsilon 4-proxyl]-NPY, the KD was 8 x 10(-10) M and koff was 2.7 x 10(-4) sec-1 yielding a value for kon of 3.3 x 10(5) sec-1 M-1. The [Ac-Tyr1, N epsilon 4-proxyl,-D-Trp32]-NPY antagonist ligand had a value of KD equal to 1.35 x 10(-7) M and koff was 1.7 x 10(-4) sec-1 leading to a value for kon of 1.2 x 10(3) sec-1 M-1. The difference in the kon rates of two orders of magnitude is interpreted as demonstrating the N-acetyl-N epsilon 4 proxyl-D-Trp32-NPY ligand binding transition state to be of higher energy then for the unmodified NPY amino acid sequence.

Characterization of Y3 receptor-mediated synaptic inhibition by chimeric neuropeptide Y-peptide YY peptides in the rat brainstem

1. Neuropeptide Y (NPY) and peptide YY (PYY) act at receptors referred to as Y1 and Y2, while the Y3 receptor is specific to NPY and does not recognize PYY. The effects of NPY, its related peptides and a series of newly constructed chimeric NPY-PYY peptides were examined on excitatory and inhibitory postsynaptic currents (e.p.s.cs and i.p.s.cs, respectively) in rat dorsomedial nucleus tractus solitarius (NTS) neurones recorded in coronal brainstem slices. Monosynaptic activity was evoked by electrical stimulation in the region of the tractus solitarius. 2. NPY (5-500 nM) inhibited e.p.s.cs and i.p.s.cs in a concentration-dependent manner. In contrast, PYY (500 nM) failed to affect either e.p.s.cs or i.p.s.cs. The N- and C-terminal parts of a series of chimeric NPY-PYY peptides were joined at positions where NPY and PYY sequences differ. In binding experiments the chimeric peptides were all about equipotent with NPY and PYY in displacing [125I]-PYY from Y1 and Y2 binding sites on SK-N-MC cells and rat hippocampus respectively. 3. In the whole cell voltage clamp recordings of NTS neurones, NPY(1-23)-PYY(24-36) and NPY(1-14)-PYY(15-36) evoked a concentration-dependent inhibition of e.p.s.cs and i.p.s.cs, while NPY(1-7)-PYY(8-36) and NPY(1-3)-PYY(4-36) were inactive. The only differences in amino acid residues between NPY(1-14)-PYY(15-36) and NPY(1-7)-PYY(8-36) reside in positions 13 and 14. 4. Furthermore, [Pro34]NPY (500 nM) was equivalent in potency to NPY itself at inhibiting monosynaptic transmission in NTS, while [Leu31,Pro34]NPY and pancreatic polypeptide (both at 500 nM) failed to affect synaptic transmission. 5. The present study has shown that NPY acts at Y3 receptors to suppress both excitatory and inhibitory currents in the NTS. The different efficacy of the chimeric NPY-PYY peptides suggests that positions 13 and 14 are of great importance for Y3 receptor recognition. Finally, this receptor type readily recognizes [Pro34]NPY, but not [Leu31,Pro34]NPY.

Combinatorial modification of natural products: preparation of unencoded and encoded libraries of Rauwolfia alkaloids

We report the preparation of combinatorial libraries which consist of derivatives of the stereoisomeric alkaloids yohimbine and rauwolscine-members of the Rauwolfia genus. The chemistry was performed on solid support using the divide-and-pool method, and involved the derivatization of the E-ring carboxylates and hydroxyls of these alkaloids with 36 amino acids and 22 carboxylic acids, respectively, to afford 792 bifunctionalized derivatives. The rauwolscine library was prepared using an encoding strategy in which the identity of each incorporated amino acid was recorded by cosynthesizing chemically inert tags prior to the pooling step. The general strategy for library synthesis exploits existing functionality present on the natural products, and should be applicable to other families of secondary metabolites.

Versatile approach to encoding combinatorial organic syntheses using chemically robust secondary amine tags

Encoded combinatorial organic synthesis has recently emerged as a powerful tool for the discovery of biologically active compounds from complex chemical libraries. This report describes a new encoding methodology that uses chemically robust secondary amines as tags. These amines are incorporated into an N-[(dialkylcarbamoyl)methyl]glycine-coding oligomer through simple chemistry that is compatible with a wide range of polymer-supported transformations useful in combinatorial synthesis. In the decoding process acidic hydrolysis of the tagging polymer regenerates the secondary amines, which after dansylation are resolved and detected at sub-picomole levels by reversed-phase HPLC. The versatility of this strategy is demonstrated here by encoded syntheses of members of several representative heterocyclic compound classes, including beta-lactams, 4-thiazolidinones, and pyrrolidines.

A double-blind comparison of bisoprolol and atenolol in patients with essential hypertension

We compared the beta 1-selective adrenoceptor antagonists bisoprolol and atenolol in a double-blind, randomized crossover study. After 4 weeks placebo phase, 59 patients with essential hypertension received either 10 mg bisoprolol or 50 mg atenolol once daily for 8 weeks, increased if necessary (target BP < or = 150/90 mmHg) to 20 and 100 mg, respectively, after 4 weeks. After a second placebo phase, crossover occurred to the alternative drug. We measured resting systolic and diastolic blood pressures and heart rate at 24 h post-dose baseline and after 4 and 8 weeks treatment. Both drugs significantly lowered systolic and diastolic blood pressures and heart rate at 8 weeks compared to baseline (all p < 0.05). Bisoprolol reduced heart rate significantly more than atenolol (p < 0.01), but systolic and diastolic blood pressure changes were not different between the two drugs. There was no difference in patient acceptability of the drugs as assessed by visual analogue scale. Despite theoretical and circumstantial evidence to suggest superiority of bisoprolol over atenolol, no significant difference between the two was found except for greater heart rate reduction with bisoprolol.

A survey of magnetic fields in the dental operatory

Recently, there has been growing concern regarding the biological effects of occupational exposure to weak time-varying magnetic fields, especially those in the extremely low-frequency range (0.1-100.0 Hz). This study examined some potential sources and intensities of 60 Hz magnetic fields produced in the dental environment. A random sample of general dental offices and selected specialty offices was visited, and the magnetic fields associated with ultrasonic scalers, amalgamators, composite light curing units, X-ray view boxes and chair lights were measured. The median 60 Hz field strengths measured at various running speeds (off, standby, low and high) and the distances from the equipment (0, 15 and 30 cm) ranged from 1.2 to 2,225 milligauss (mG). Field strengths fell off quickly with distance, but were less affected by the running speed of the equipment. They also varied among the five types of equipment tested. This was likely due to variations in the make, model and age of the equipment. The 60 Hz magnetic field strengths recorded in the dental operatory were comparable to those reported from measurements of common household appliances. However, in view of recent concerns with respect to the possible effects of magnetic fields, it is suggested that exposures be minimized and the concept of prudent avoidance be employed.

Sequence specificity in the recognition of the epidermal growth factor receptor by the abl Src homology 2 domain

The transforming activity of the abl gene product requires a functional src homology 2 (SH2) domain. An assay was developed to evaluate this function by examining binding of a bacterially-expressed abl SH2 domain to the activated EGF receptor, used as a surrogate tyrosine phosphorylated protein. The sequence specificity of this interaction has been explored with a series of point mutants of EGF receptor. Analysis of equilibrium binding reveals that substitution of Tyr1086 for Phe in the EGF receptor produced a 10-fold reduced affinity for abl SH2 domain binding as compared to the wildtype receptor. Moreover, a phosphorylated peptide modeled on the sequences surrounding Tyr1086 specifically inhibits abl SH2 binding, with an IC50 of approximately 10 microM. Evaluation of a series of additional peptides, modeled on the Tyr1086 sequence, revealed that the carboxy terminal residues directly next to the phosphotyrosine were particularly critical to this binding. Molecular modeling studies of the pTyr1086 peptide revealed the potential hydrophobic, ionic and hydrogen bonding interactions involved in the functions of the abl SH2 domain.

Protein tyrosine phosphatase substrate specificity: size and phosphotyrosine positioning requirements in peptide substrates

The structural requirements of substrates for two recombinant protein tyrosine phosphatases (PTPases) are probed using various-sized synthetic phosphotyrosine (pY)-containing peptides corresponding to the autophosphorylation site in EGF receptor (EGFR) at Y992. The peptide EGFR988-998 (DADEpYLIPQQG) is chosen as a template due to its favorable kinetic constants. The contribution of individual amino acids on both sides of pY to binding and catalysis was assessed by kinetic analysis using a continuous, spectrophotometric assay. For both Yersinia PTPase and a soluble recombinant mammalian PTPase of 323 amino acid residues (rat PTP1), efficient binding and catalysis required six amino acids including the pY residue, i.e., four residues N-terminal to pY and one residue C-terminal to pY. Thus, PTPase substrate specificity is primarily dictated by residues to the N-terminal side of pY. The pY moiety and the rest of the peptide interact with PTPases in a cooperative manner. The presence of pY in the peptide substrate is necessary but not sufficient for high-affinity binding, since phosphotyrosine and other simple aryl phosphates exhibit weak binding, and dephosphorylated peptides do not bind to PTPases. Two variations on the pY moiety are also examined in order to assess their utility in PTPase inhibitor design. It is demonstrated that the thiophosphoryl analog in which one of the phosphate oxygens is replaced by sulfur can be hydrolyzed by PTPases, whereas the phosphonomethylphenylalanine analog in which the tyrosyl oxygen is replaced by a CH2 group is a competitive and nonhydrolyzable inhibitor, with Ki values of 18.6 and 10.2 microM, respectively, for the Yersinia PTPase and the rat PTP1.

Combination therapy with amlodipine and captopril for resistant systemic hypertension

This study was conducted to assess the therapeutic utility of combining amlodipine with captopril in patients with moderate-to-severe hypertension. Patients had hypertension of WHO grades I-III, with initial mean sitting and standing diastolic blood pressure of 100-119 mm Hg (phase V) after 2-4 weeks on placebo, and had remained uncontrolled (diastolic blood pressure > 95 mm Hg) despite a further 4 weeks on low-dose captopril. Twenty-nine patients entered the computer-randomized, double-blind, placebo-controlled, 2-way crossover comparison of either amlodipine 10 mg once daily or matching placebo added to continued therapy with captopril 25 mg twice daily for 4 weeks. Patients then acted as their own control and received the alternative amlodipine/placebo treatment plus their continued captopril therapy for another 4 weeks. Once-daily amlodipine was shown to be effective when combined with captopril. Mean baseline supine systolic blood pressure decreased from 167 to 149 mm Hg and standing systolic blood pressure from 167 to 144 mm Hg. Mean supine diastolic blood pressure decreased from 105 to 92 mm Hg, and standing diastolic blood pressure decreased from 110 to 96 mm Hg. The placebo-corrected amlodipine differences in mean changes from captopril baseline were -18/-12.2 mm Hg for supine and -20.1/-11.9 mm Hg for standing systolic and diastolic blood pressures, respectively (p < 0.001 for all 4 measurements). The most common side effects encountered with amlodipine were flushing and pedal edema. The combination of amlodipine and captopril was well tolerated, and no patient discontinued therapy. No significant treatment-related effects on biochemical and hematologic parameters were noted.

Measurement and management of cardiovascular risk factors--is screening worthwhile?

Coronary heart disease has been described as Scotland's national disease and ways of reducing its incidence are therefore of paramount importance especially in younger males. A recent British Medical Journal paper has indicated that general practitioners can make little impact on patients' lifestyles. This paper shows that a cohort of Scottish men (Social Class III-V) responded well (80%) to offers of screening for risk factors of CHD, continued to attend for review and showed highly significant changes in their risk factor profiles. A committed enthusiastic primary care team have shown the potential for reducing coronary risk factors in so-called healthy men.

The incidence of first-dose hypotension with quinapril in patients with mild to moderate hypertension

A total of 2242 patients with mild to moderate hypertension (diastolic pressure 95-120 mmHg) were randomised on a double-blind basis to receive a single dose of placebo, 5 mg quinapril or 10 mg quinapril. Patients were identified who: (a) met the blood pressure (BP) criteria for first-dose hypotension (sitting or standing systolic BP < 100 mmHg, or a fall in systolic BP > or = 20 mmHg on standing); (b) had symptoms suggestive of hypotension; and (c) met the BP criteria and had symptoms. In all three classifications there were no statistically significant differences between the incidences in placebo and combined active treatment groups, or between those in the two quinapril groups. No associated serious adverse events were reported. In the low-risk population studied, it would appear that the incidence of first-dose hypotension with quinapril is similar to placebo and is not dose-related.

Guidelines for resuscitation and transfer of patients with serious head injury

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Substrate specificity of the protein tyrosine phosphatases

The substrate specificity of a recombinant protein tyrosine phosphatase (PTPase) was probed using synthetic phosphotyrosine-containing peptides corresponding to several of the autophosphorylation sites in epidermal growth factor receptor (EGFR). The peptide corresponding to the autophosphorylation site, EGFR988-998, was chosen for further study due to its favorable kinetic constants. The contribution of individual amino acid side chains to the binding and catalysis was ascertained utilizing a strategy in which each amino acid within the undecapeptide EGFR988-998 (DADEpYLIPQQG) was sequentially substituted by an Ala residue (Ala-scan). The resulting effects due to singular Ala substitution were assessed by kinetic analysis with two widely divergent homogeneous PTPases. A "consensus sequence" for PTPase recognition may be suggested from the Ala-scan data as DADEpYAAPA, and the presence of acidic residues proximate to the NH2-terminal side of phosphorylation is critical for high-affinity binding and catalysis. The Km value for EGFR988-998 decreased as the pH increased, suggesting that phosphate dianion is favored for substrate binding. The results demonstrate that chemical features in the primary structure surrounding the dephosphorylation site contribute to PTPase substrate specificity.

A continuous spectrophotometric and fluorimetric assay for protein tyrosine phosphatase using phosphotyrosine-containing peptides

Two continuous assays for protein tyrosine phosphatases (PTPases) have been developed using phosphotyrosine containing peptide substrates. These assays are based on the marked differences in the spectra of the peptide before and after the removal of the phosphate group. The increase in the absorbance at 282 nm or the fluorescence at 305 nm of the peptide upon the action of PTPase can be followed continuously and the resulting progress curve (time course) can be analyzed directly using the integrated form of the Michaelis-Menten equation. The procedure is convenient and efficient, since both kcat and Km values can be obtained in a single run. The difference absorption coefficient (delta epsilon) at 282 nm is relatively insensitive to the pH of the reaction media. These techniques were applied to two homogeneous recombinant PTPases employing six phosphotyrosine-containing peptides. Km and kcat values obtained from the progress curve analysis were similar to those determined by the traditional initial rate inorganic phosphate assay. The peptides corresponding to autophosphorylation sites in Neu, p56lck, and p60src proteins show distinct behavior with the Yersinia PTPase, Yop51*, and the mammalian PTPase (PTP1U323). In both cases, the kcat values were relatively constant for all the peptides tested whereas the Km values were very sensitive to the amino acid sequence surrounding the tyrosine residue, especially in the case of Yop51*. Thus, both Yop51* and PTP1U323 show differential recognition of the phosphotyrosyl residues in the context of distinct primary structure of peptide substrates.

Cough and enalapril: assessment by spontaneous reporting and visual analogue scale under double-blind conditions

The incidence and prevalence of cough related to enalapril was assessed by spontaneous reporting and a visual analogue scale during a 6 month random double-blind parallel-group study comparing enalapril with nifedipine. Cough was reported spontaneously by 6.2% of enalapril-treated patients, and by none on nifedipine (NS). No patient had to discontinue enalapril because of cough. After 24 weeks treatment increases in visual analogue scale scores for cough frequency greater than or equal to 8 mm were more common for enalapril than nifedipine (difference 21.5%, 95% CI 7.3-35.7%). Increased cough frequency by visual analogue scale was present throughout the study in women, but less consistently in men. High scores for cough were not related to the dose of enalapril. Cough with enalapril was not an important problem during the 6 months of treatment. However increased cough frequency could be detected by visual analogue scale, with a frequency consistent with that observed in open clinic-based studies of longer duration. These findings suggest that ACE inhibitor-induced cough may increase in severity over time, and that even a period of 6 months treatment is too short to evaluate this side-effect adequately.

Doxazosin in 'resistant' hypertension

A study of doxazosin added to baseline therapy with a beta-adrenoceptor blocker plus a diuretic in the treatment of patients 'resistant' to the baseline therapy, showed that it was effective and generally well tolerated. The study was, however, open-label and lacked comparison with other third-line drugs.

Enalapril and nifedipine in the treatment of mild to moderate essential hypertension: a 6 month comparison

1. In a double-blind, randomised, parallel group study, 128 patients with sitting diastolic blood pressure between 95 and 125 mm Hg (Phase V) after 2-4 weeks run-in on placebo, received enalapril 10-40 mg once daily (65 patients) or nifedipine retard 10-40 mg twice daily (63 patients), utilising a double dummy technique. Dual target blood pressures were less than 150 mm Hg systolic and less than 90 mm Hg sitting diastolic. Inadequate responders had hydrochlorothiazide 12.5-50 mg once daily added. 2. The 3 h post-dose sitting blood pressures were lowered by 18/14 mm Hg (enalapril) and 20/14 mm Hg (nifedipine), but nifedipine gave greater standing reductions (16/13 mm Hg enalapril, 22/17 mm Hg nifedipine). The dual target blood pressures were achieved by 45% of those taking enalapril monotherapy and 43% of those taking nifedipine monotherapy. At the end of the hydrochlorothiazide phase the dual target pressures were achieved by 63% of the enalapril group and 56% of the nifedipine group. 3. Overall, 17 patients reported adverse events during the placebo run-in. During the active treatment-periods, 42 patients in the enalapril group experienced adverse events, as did 49 of those on nifedipine. Orthostatic effects were confined to those taking enalapril, whereas flushing/erythema, oedema and palpitations were more common in the nifedipine group. 4. Five patients in the enalapril and 14 in the nifedipine groups were withdrawn because of adverse events. One of those withdrawn on enalapril had angioneurotic oedema.(ABSTRACT TRUNCATED AT 250 WORDS)

Comparison of once daily atenolol, nitrendipine and their combination in mild to moderate essential hypertension

1. The aim of the study was to compare the efficacy and the tolerability of treatment with atenolol (50-100 mg once daily), nitrendipine (20-40 mg once daily) and their combination (atenolol 50 mg + nitrendipine 20 mg) once daily in patients with mild to moderate essential hypertension. 2. The study was a randomised, double-blind, placebo controlled parallel groups design: blood pressures were measured at 'trough' effect (i.e. 24 h after dosing) to assess the adequacy of once-daily treatment. 3. Mean blood pressures (mm Hg) recorded on four occasions over 12 weeks of treatment were significantly lower both with atenolol (155/97 sitting: 155/104 standing) and with the combination of atenolol plus nitrendipine (153/96 sitting: 152/104 standing) than with placebo (169/108 sitting: 169/114 standing). Nitrendipine alone had no significant effect on blood pressure 24 h after dosing (165/104 sitting: 165/110 standing). 4. Withdrawals due to adverse effects were more common during treatment with nitrendipine: 7/32 of the patients experienced adverse effects attributable to intense systemic vasodilatation (e.g., flushing, erythema, headache). 2/37 patients taking atenolol were withdrawn: one because he developed a psoriatic rash and the other because of impaired peripheral circulation. Of the 35 patients taking combination treatment, two were withdrawn: one developed headaches and dyspnoea, and the other asthma. 5. The results suggest that once daily dosing with nitrendipine does not control blood pressure throughout the 24 h period in the majority of patients, and is associated with a considerable burden of adverse effects. Combination treatment was better tolerated but appeared to offer no advantages over atenolol alone in terms either of blood pressure control or adverse effects.

The effects of indomethacin and sulindac upon the blood pressures of individuals with untreated labile or mild hypertension

Twelve patients (mean age 48.8 years, 5 females) with untreated labile or mild essential hypertension completed a randomised, double-blind crossover study comparing the effects of two-week courses of indomethacin, sulindac and matching placebo upon sitting and standing blood pressure. Both indomethacin and sulindac significantly increased systolic BP when compared with placebo; indomethacin tended to have a greater pressor effect than sulindac. During treatment with indomethacin, the mean BP rose from 136/86 to 149/92 (sitting), and from 136/93 to 150/99 standing. The extent of the pressor response was unrelated to baseline BP. The results indicate that both non-steroidal anti-inflammatory drugs (NSAIDs) have a significant pressor effect in individuals with untreated labile or mild hypertension. The fact that sulindac had a pressor effect implies that this response may be unrelated to inhibition of renal prostaglandins, or that the renal-sparing effect of sulindac is only relative. Extra-renal prostaglandins may play a role in the control of BP in this population. Individuals with labile or mild hypertension do not appear to exhibit exaggerated pressor responses during treatment with these NSAIDs, as similar increases in BP have been reported in normal subjects.

Comparison of the efficacy and acceptability of nicardipine and propranolol, alone and in combination, in mild to moderate hypertension

1. We evaluated the relative efficacies and tolerability of various low-dose combinations of nicardipine and propranolol in patients with mild-moderate essential hypertension (DBP Phase V of greater than 90-125 mmHg; WHO Grades I and II) in order to select the best one. 2. Sixty patients completed the double-blind, balanced, randomised three-way cross-over protocol, with each phase lasting 4 weeks, and in which twice daily nicardipine 40 mg or propranolol 80 mg was compared with four twice daily combinations of nicardipine (20 or 30 mg) plus propranolol (40 or 80 mg). 3. At 'peak' effect time (i.e., 2 h post-dosing) all four treatment combinations were significantly more effective than propranolol, with effects ranging from 9-23 mmHg (systolic) and 5-15 mmHg (diastolic). Only the two 30 mg nicardipine combinations with propranolol were more effective than nicardipine monotherapy, further reducing BP by 8-13 mmHg (systolic) and 5-7 mmHg (diastolic); there were no significant differences between them. 4. 'Trough' diastolic pressures were not different between treatments and 'trough' BP control was sub-optimal on all treatments. 5. 70% of patients on nicardipine monotherapy, 33% of those on propranolol monotherapy and 30% of patients during the placebo run-in complained of symptoms. In terms of complaint rates, there was little to choose between the four combinations (27-33%). Serum potassium and creatinine levels were elevated following propranolol monotherapy by 0.19 mmol 1-1 and 6.5 mumol 1-1 respectively (P less than 0.01 for both) and following the nicardipine 30 mg/propranolol 80 mg combination. Nicardipine monotherapy elevated serum T4 levels by an average of 0.57 ng dl-1 (P less than 0.05). 6. The twice daily combination of nicardipine 30 mg plus propranolol 40 mg was therefore the optimum one in terms of its efficacy and tolerability. Further studies need to be performed to test the hypothesis that a higher dose of propranolol might ameliorate troublesome vasodilator side effects. However, none of the treatments studied was ideal for clinical use in the twice daily dosage used in this study.

Quinapril: a double-blind, placebo-controlled trial in essential hypertension

Quinapril HCl is a novel, nonsulfhydryl angiotensin-converting enzyme (ACE) inhibitor. The Study Group evaluated its efficacy (20, 40, 80 mg daily with forced dose titration determination at trough blood pressure) once daily versus twice daily versus placebo, as well as its tolerability and safety, in 270 patients with mild to moderate essential hypertension (WHO Stages I and II, sitting diastolic blood pressure [DPB] greater than or equal to 95 mm Hg), for twelve weeks. Reductions in DBP of up to 13 mm Hg were obtained, and in full dosage more than 65% of patients achieved a reduction in DBP of 10 mm Hg or more from baseline or reduced their DBP to 90 mm Hg or less. Quinapril was well tolerated, and reported adverse effects were scarcely more frequent than in the placebo group. Once daily doses of quinapril were as safe and effective as twice-daily doses. Quinapril is likely to exhibit good therapeutic utility in the management of essential hypertension.