The ‘three-legged stool’

Many hospitals do not have a structured process of consent, the attainment of which can often be rather ‘last-minute’ and somewhat chaotic. This is a surprising state of affairs as spinal surgery is a high-risk surgical specialty with potential for expensive litigation claims. More recently, the Montgomery ruling by the United Kingdom Supreme Court has placed the subject of informed consent into the spotlight.

There is a paucity of practical guidance on how a consent process can be achieved in a busy clinical setting. The British Association of Spinal Surgeons (BASS) has convened a working party to address this need. To our knowledge this is the first example of a national professional body, representing a single surgical specialty, taking such a fundamental initiative.

In a hard-pressed clinical environment, the ability to achieve admission reliably on the day of surgery, in patients at ease with their situation and with little likelihood of late cancellation, will be of great benefit. It will reduce litigation and improve the patient experience.

Cite this article: Bone Joint J 2016;98-B:1427–30.

Canonical Wnt signaling negatively regulates platelet function

Wnts regulate important intracellular signaling events, and dysregulation of the Wnt pathway has been linked to human disease. Here, we uncover numerous Wnt canonical effectors in human platelets where Wnts, their receptors, and downstream signaling components have not been previously described. We demonstrate that the Wnt3a ligand inhibits platelet adhesion, activation, dense granule secretion, and aggregation. Wnt3a also altered platelet shape change and inhibited the activation of the small GTPase RhoA. In addition, we found the Wnt-beta-catenin signaling pathway to be functional in platelets. Finally, disruption of the Wnt Frizzled 6 receptor in the mouse resulted in a hyperactivatory platelet phenotype and a reduced sensitivity to Wnt3a. Taken together our studies reveal a novel functional role for Wnt signaling in regulating anucleate platelet function and may provide a tractable target for future antiplatelet therapy.

Differential stimulation of monocytic cells results in distinct populations of microparticles

BACKGROUND

Microparticles (MPs), small vesicles shed from stimulated cells, permit cross-talk between cells within a particular environment. Their composition is thought to reflect their cell of origin, and differs according to whether they are produced by stimulation or by apoptosis. Whether MP properties vary according to stimulus is not yet known.

METHODS

We studied the characteristics of MPs produced from monocytic THP-1 cells upon stimulation with lipopolysaccharide or a soluble P-selectin chimera, using proteomics, flow cytometry, western blotting, and electron microscopy.

RESULTS

Utilizing a novel criterion of calcein-AM staining to define MPs, we found that MP populations were similar with respect to size, presence and organization of cytoskeleton, and expression of certain antigens. The MPs shared the same level of procoagulant activity. We found that MPs also have distinct characteristics, depending on stimuli. These include differences in phosphatidylserine expression and expression of proteins from specific subcellular locations such as the mitochondria, and of unique antigens such as leukocyte-associated immunoglobin-like-receptor (LAIR)-1, which was found only upon stimulation with the soluble P-selectin chimera.

CONCLUSION

We found that the properties of MPs depend on the stimulus that produced them. This supports the concept that monocytic MPs differentially modulate thrombosis, inflammation and immune regulation according to stimulus.

Recent advances in the characterisation of the platelet membrane system by proteomics

Platelets are the principle effectors of cellular haemostasis and key mediators in the pathogenesis of thrombosis. A variety of membrane receptors determine platelet reactivity with numerous agonists and adhesive proteins, and therefore represent key targets for the development of antiplatelet drug therapy. Here, we summarise recent advances in the analysis of the complex platelet membrane system achieved through the integration of platelet biology and proteomics.

Bioinformatic discovery of novel bioactive peptides

Short synthetic oligopeptides based on regions of human proteins that encompass functional motifs are versatile reagents for understanding protein signaling and interactions. They can either mimic or inhibit the parent protein's activity and have been used in drug development. Peptide studies typically either derive peptides from a single identified protein or (at the other extreme) screen random combinatorial peptides, often without knowledge of the signaling pathways targeted. Our objective was to determine whether rational bioinformatic design of oligopeptides specifically targeted to potentially signaling-rich juxtamembrane regions could identify modulators of human platelet function. High-throughput in vitro platelet function assays of palmitylated cell-permeable oligopeptides corresponding to these regions identified many agonists and antagonists of platelet function. Many bioactive peptides were from adhesion molecules, including a specific CD226-derived inhibitor of inside-out platelet signaling. Systematic screens of this nature are highly efficient tools for discovering short signaling motifs in molecular signaling pathways.

Enrichment of phosphotyrosine proteome of human platelets by immunoprecipitation

Proteomics offers the opportunity to comprehensively investigate the anucleate platelet. Here, we present a detailed procedure for enrichment by immunoprecipitation, using the monoclonal antibody 4G10, of the dynamic phosphotyrosine proteome of human platelets. Such an approach offers the possibility of capturing the dynamic tyrosine phosphorylation events that occur upon platelet activation and aggregation, with an aim to identify novel signaling proteins.

Meta-analysis of sentinel lymph node biopsy after preoperative chemotherapy in patients with breast cancer

BACKGROUND

Women with breast cancer are more frequently being treated with preoperative neoadjuvant chemotherapy. The reliability of sentinel lymph node biopsy (SLNB) following chemotherapy has not been determined. This was a meta-analysis of studies that examined the results of SLNB after preoperative chemotherapy.

METHODS

Included articles had to meet two criteria. First, patients had to have had operable breast cancer and to have undergone SLNB after preoperative chemotherapy and, second, patients had to have undergone subsequent axillary lymph node dissection. Meta-analyses were performed in which Bayesian hierarchical models were created to estimate the identification rate (IR) and sensitivity of SLNB in this setting.

RESULTS

Twenty-one studies were identified that included a total of 1273 patients. The IRs reported ranged from 72 to 100 per cent, with a pooled estimate of 90 per cent. The sensitivity of SLNB ranged from 67 to 100 per cent, with a pooled estimate of 88 (95 per cent confidence interval 85 to 90) per cent. Meta-analyses performed using Bayesian modelling resulted in (posterior) estimates for IR and sensitivity of 91 (95 per cent credible interval 88 to 94) and 88 (95 per cent credible interval 84 to 91) per cent respectively.

CONCLUSION

SLNB is a reliable tool for planning treatment after preoperative chemotherapy.

Using proteomics to identify potential therapeutic targets in platelets

Proteomics has provided powerful new insights into the complex events of the anucleate platelet and has revealed many potential protein targets in the search for suitable agents for thrombotic disease. In the present study, we summarize recent proteomic approaches to analyse specific platelet subproteomes, such as the platelet releasate, the platelet phosphotyrosine proteome and characterization of the proteins associated with membrane lipid rafts.

Treatments used in women with interstitial cystitis: the interstitial cystitis data base (ICDB) study experience. The Interstitial Cystitis Data Base Study Group

OBJECTIVES

To evaluate the frequency and types of treatments reported at baseline in women who entered the Interstitial Cystitis Data Base (ICDB) cohort study.

METHODS

From 1993 to 1997, 581 women were enrolled and followed in the ICDB. All treatments reported at study entry, including those prescribed for interstitial cystitis (IC) and concomitant medications, were reviewed. The number and types of treatments were evaluated with respect to baseline factors such as prior diagnosis of IC and symptom severity.

RESULTS

One hundred five (18%) women were receiving no therapy at baseline. Single-mode therapy was reported by 195 (34%) women, and a combination of two treatments was reported by 119 (21%) women. Three or more treatments were reported in 162 (28%) women. A total of 183 different types of therapies were recorded. The five most commonly used therapies for IC symptoms were cystoscopy and hydrodistention, amitriptyline, phenazopyridine, special diet, and intravesical heparin. Because most patients entered the ICDB before the approval of oral pentosan polysulfate sodium (PPS), only 6% of women reported oral PPS use at baseline. There were statistically significant associations between the number and types of treatments and clinical center, a prior diagnosis of IC, and symptom severity.

CONCLUSIONS

The diversity of IC therapies underscores the lack of understanding about the treatment of this syndrome. Further research in IC is essential to develop and to evaluate rational therapies and treatment algorithms. These algorithms should be "evidence based" and should be revised as the underlying etiology and pathophysiology of IC is delineated.

Gene expression analysis by massively parallel signature sequencing (MPSS) on microbead arrays

We describe a novel sequencing approach that combines non-gel-based signature sequencing with in vitro cloning of millions of templates on separate 5 microm diameter microbeads. After constructing a microbead library of DNA templates by in vitro cloning, we assembled a planar array of a million template-containing microbeads in a flow cell at a density greater than 3x10(6) microbeads/cm2. Sequences of the free ends of the cloned templates on each microbead were then simultaneously analyzed using a fluorescence-based signature sequencing method that does not require DNA fragment separation. Signature sequences of 16-20 bases were obtained by repeated cycles of enzymatic cleavage with a type IIs restriction endonuclease, adaptor ligation, and sequence interrogation by encoded hybridization probes. The approach was validated by sequencing over 269,000 signatures from two cDNA libraries constructed from a fully sequenced strain of Saccharomyces cerevisiae, and by measuring gene expression levels in the human cell line THP-1. The approach provides an unprecedented depth of analysis permitting application of powerful statistical techniques for discovery of functional relationships among genes, whether known or unknown beforehand, or whether expressed at high or very low levels.

Phase I clinical and pharmacokinetic study of S9788, a new multidrug-resistance reversal agent given alone and in combination with doxorubicin to patients with advanced solid tumors

PURPOSE

The objectives of this phase I study were to evaluate the toxic effects and the maximum tolerated dose (MTD) of S9788, a new modifier of multidrug resistance (MDR), when given alone and in combination with doxorubicin to patients with advanced solid tumors; to achieve a potentially active plasma concentration of S9788; and to study the pharmacokinetics of both drugs.

METHODS

A total of 26 patients (median age 58 years) entered the study. S9788 was given alone as a 30-min infusion at day 1 and in combination with a 50-mg/m2 bolus of doxorubicin at days 8 and 29. Dose levels of S9788 were escalated from 8 to 96 mg/m2 according to the modified Fibonacci scheme. Plasma samples were taken predose as well as during and up to 48 h after the beginning of infusion for S9788 and doxorubicin quantitation. Fractionated urine samples were also collected for up to 24 h for S9788 determination.

RESULTS

The dose-limiting side effects of S9788 consisted of bradycardia, sometimes associated with faintness or dizziness. The MTD of S9788 was 96 mg/m2. No enhancement of doxorubicin toxicity was observed. One partial response (duration 140 days) was observed at 96 mg/m2 in a patient with multiple lung metastases from a refractory urothelial carcinoma. Pharmacokinetic studies were performed in 24 patients. Since the mean apparent elimination half-life of S9788 was 46 +/- 23 h and the last plasma sampling time was 48 h, only model-independent parameters were considered. Plasma levels of S9788 were below the limit of quantitation (4 x 10[-3] microM) before each drug administration. S9788 plasma levels of up to 3.7 microM could be obtained with this administration schedule. The urinary elimination of the unchanged drug was negligible, whatever the collection period. In spite of the large inter- and intraindividual variability, plasma pharmacokinetics of S9788 given as a 30-min i.v. infusion were linear up to 96 mg/m2 and were not modified by doxorubicin administration. Doxorubicin pharmacokinetic parameters did not seem to be influenced by S9788 coadministration.

CONCLUSION

The dose-limiting toxicity of S9788 consisted of bradycardia or clinical symptoms suggesting a vasovagal impact such as faintness or dizziness. The MTD of S9788 was 96 mg/m2. The pharmacokinetic parameters of doxorubicin in this study were close to those usually described and were not influenced by escalation of the S9788 dose. No pharmacokinetic interaction was observed between S9788 and doxorubicin. The clinical tolerability of the combined treatment is in good agreement with the pharmacokinetic findings, since no enhancement of doxorubicin toxicity was observed.

Associations among cystoscopic and urodynamic findings for women enrolled in the Interstitial Cystitis Data Base (ICDB) Study

OBJECTIVES

Interstitial cystitis is a symptom complex characterized by pelvic pain, urinary urgency, urinary frequency, and nocturia. Patients with these symptoms, at the 5 clinical centers participating in the National Interstitial Cystitis Data Base (ICDB) Study, have been evaluated with history and physical exams, questionnaires, and urodynamic studies.

METHODS

Of the 388 female subjects entered in the study as of December 31, 1995, 150 women have undergone cystoscopy with hydrodistension. The data from the endoscopic procedures and the urodynamic studies were analyzed. The associations among cystoscopic and urodynamic findings were reviewed.

RESULTS

Patient demographics of this subgroup show a predominance of Caucasians 139/150 (92.7%), with the average age being 43 (+/-13.2) years. Of the total, 17 patients (11.3%) had a Hunner's patch (HP). The prevalence by center varied from a low of 2/38 (5.3%) to a high of 3/9 (33.3%). Bloody effluent following hydrodistension was present in 113/150 (75.3%). Glomerulations appeared in varying degrees (mild, moderate, severe) in 91.3% of the 150 patients. There was a strong inverse relationship (P < 0.001) between bladder capacity under anesthesia and the presence of a HP (mean of 845 cc with HP absent versus a mean of 531 cc when present). The incidence of HP varied from 67.6% among women with a bladder capacity at hydrodistension of < 400 cc to 3.8% for those with a bladder capacity of at least 800 cc. The presence and increasing severity of glomerulations was positively associated (P < 0.003) with the presence of HP, ranging from 0/13 (0%) when glomerulations were not present to 6/31 (19.4%) when glomerulations were graded as severe. Of the patients with HP, 17/17 (100%) had glomerulations after hydrodistension. HP is more closely associated with the moderate to severe range of glomerulations (P < 0.01). Nearly half of the patients with HP or 8/17 (47.1%) had "moderate" glomerulations, while 6/17 (35.3%) had "severe" glomerulations. The volume at first sensation to void on urodynamics (mean 87 cc without HP versus 34.7 cc with HP) was highly inversely associated (P = 0.002) with the presence of HP, but not with any of the other cystoscopic findings. Of patients with HP, 94% had a volume at first sensation to void of < or = 50 cc where only 36% of patients without HP had a volume at first sensation to void of < or = 50 cc. The volume at maximum capacity on urodynamics was positively associated with the volume at hydrodistension (P < 0.001).

CONCLUSIONS

Overall, patients with HP had lower bladder capacities, lower volumes at first sensation to void, and more severe glomerulations. Thus, the presence of HP would imply a more severe case of interstitial cystitis. Logically, a higher bladder capacity on cystometrogram is associated with a higher volume at the time of hydrodistension, and bloody effluent is associated with more severe glomerulations.

Phase I study of RP 49532A, a new protein-synthesis inhibitor, in patients with advanced refractory solid tumors

Giroline (RP 49532A) is a new protein-synthesis inhibitor with broad antitumor activity in experimental models. In the present phase I study, Giroline was given by 24-h i.v. infusion every 3 weeks at doses ranging from 3 to 15 mg/m2 to 12 patients with advanced refractory solid tumors. The dose-limiting toxic effects were delayed hypotension and severe asthenia. The maximum tolerated dose (MTD) was 15 mg/m2. Transient nausea and vomiting during infusion were reported at all dose levels. Mild reversible prolongation of prothrombin time and activated partial thromboplastin time was observed in most patients at dose levels above 3 mg/m2. No antitumor activity was observed. The toxicity profile of Giroline precludes further evaluation in cancer patients.

Lack of association between patients' measured burden of disease and risk for hospital readmission

Identifying patients at increased risk for hospital readmission is important for clinicians, health policy-makers, hospital administrators, and researchers. We used a retrospective case-control design to compare the clinimetric properties of five validated indices that measure a patient's disease burden. The study was conducted on a random sample of patients discharged from the general medicine service at the Durham Department of Veterans Affairs Medical Center. Trained observers (two research assistants, one nurse, and two physicians) blinded to readmission status abstracted the required data elements from the medical record for three indices (Charlson, Kaplan-Feinstein, Index of Coexistent Disease). The hospital's computer provided data elements for two indices (Smith, adapted Charlson). Indices varied in the time required to complete, the ability to capture individual heterogeneity, and inter-observer variability. However, none of the indices discriminated among patients who did and those who did not have 6-month hospital readmissions. Factors other than summary scores derived from these indices should be used to identify patients at high risk for readmission.

The hamster hippocampal slice: II. Neuroendocrine modulation

The effects of exposing hamster hippocampal slices to the gonadal steroids estradiol and testosterone and to delta-9-tetra-hydrocannabinol (delta 9-THC) are described. At 10(-10)M estradiol and testosterone act as facilitatory neuromodulators on hippocampal slices obtained from male and diestrous female hamsters, respectively. At 10(-11)M, THC acts to facilitate responses in hippocampal slices from male animals. All three drugs displayed a rapid onset (less than 10 min), and responses were significantly greater than those of vehicle controls. These results will permit the use of the hamster in investigations of the biobehavioral role of steroid modulation of brain excitability.