Hemostatic plug formation in normal and von Willebrand pigs: the effect of the administration of cryoprecipitate and a monoclonal antibody to Willebrand factor

Hemostatic plug (HP) formation was investigated in the ear bleeding time incision in normal and von Willebrand pigs. HP volume was calculated by integrating the areas of serial sections. In normal pigs (n = 11), platelets immediately formed a layer on the surface of the cut channel. Platelet aggregates formed at the ends of transected vessels and gradually enlarged. Finally, all transected vessels were occluded by HP and bleeding stopped. In contrast, large HPs were formed in the incision in von Willebrand's disease (vWD) pigs (n = 4); these HPs did not cover the ends of the transected vessels, which continued to bleed, allowing the formation of large hemostatically ineffective platelet aggregates in the incision. Canals traversed these HPs, and bleeding from the open vessels may have continued through them. After infusion of cryoprecipitate into a vWD pig, the bleeding time shortened, and the morphological findings of the HPs were similar to those of normal pigs. In normal pigs (n = 3) infused with an anti- Willebrand factor monoclonal antibody, which prolonged the bleeding time, a large HP formed in the incision, similar to that observed in the vWD pig. The volume of the normal and vWD HPs increased with time. These in vivo findings suggest that Willebrand factor is involved in the localization of the HP to the damaged vessel and may also play a role in platelet-platelet interaction. A computerized morphometric technique was used for measuring the volume of the hemostatic plugs and the distance of sequential points on the perimeter of the HP from the center of selected bleeding vessels.     

Selecting Constant Work Rates for Endurance Testing in COPD: The Role of the Power-Duration Relationship

Constant work rate (CWR) exercise testing is highly responsive to therapeutic interventions and reveals physiological and functional benefits. No consensus exists, however, regarding optimal methods for selecting the pre-intervention work rate. We postulate that a CWR whose tolerated duration (t_lim) is 6 minutes (WR₆) may provide a useful interventional study baseline. WR₆ can be extracted from the power-duration relationship, but requires 4 CWR tests. We sought to develop prediction algorithms for easier WR₆ identification using backward stepwise linear regression, one in 69 COPD patients (FEV₁ 45 ± 15% pred) and another in 30 healthy subjects (HLTH), in whom cycle ergometer ramp incremental (RI) and CWR tests with t_lim of ～6 minutes had been performed. Demographics, pulmonary function, and RI responses were used as predictors. We validated these algorithms against power-duration measurements in 27 COPD and 30 HLTH (critical power 43 ± 18W and 231 ± 43W; curvature constant 5.1 ± 2.7 kJ and 18.5 ± 3.1 kJ, respectively). This analysis revealed that, on average, only corrected peak work rate ( = WR_peak–1 min × WR_slope) in RI was required to predict WR₆ (COPD SEE = 5.0W; HLTH SEE = 5.6W; R² > 0.96; p < 0.001). In the validation set, predicted and actual WR₆ were strongly correlated (COPD R² = 0.937; HLTH 0.978; p < 0.001). However, in COPD, unlike in HLTH, there was a wide range of t_lim values at predicted WR₆: COPD 8.3 ± 4.1 min (range 3.6 to 22.2 min), and HLTH 5.5 ± 0.7 min (range 3.9 to 7.0 min). This analysis indicates that corrected WR_peak in an incremental test can yield an acceptable basis for calculating endurance testing work rate in HLTH, but not in COPD patients.     

Fundamentals of randomized clinical trials in wound care: Reporting standards

In wound care research, available high‐level evidence according to the evidence pyramid is rare, and is threatened by a poor study design and reporting. Without comprehensive and transparent reporting, readers will not be able to assess the strengths and limitations of the research performed. Randomized clinical trials (RCTs) are universally acknowledged as the study design of choice for comparing treatment effects. To give high‐level evidence the appreciation it deserves in wound care, we propose a step‐by‐step reporting standard for comprehensive and transparent reporting of RCTs in wound care. Critical reporting issues (e.g., wound care terminology, blinding, predefined outcome measures, and a priori sample size calculation) and wound‐specific barriers (e.g., large diversity of etiologies and comorbidities of patients with wounds) that may prevent uniform implementation of reporting standards in wound care research are addressed in this article. The proposed reporting standards can be used as guidance for authors who write their RCT, as well as for peer reviewers of journals. Endorsement and application of these reporting standards may help achieve a higher standard of evidence and allow meta‐analysis of reported wound care data. The ultimate goal is to help wound care professionals make better decisions for their patients in clinical practice.     

Mammary gland development in early pubertal female macaques

Ductal morphogenesis of the mammary gland occurs largely in the early pubertal period under the influence of ovarian sex hormones. In this study we characterized developing ductal structures in breast tissue of 14 female prepubertal or early pubertal rhesus monkeys (average age, 2.6 +/- 0.1 years). Serum estradiol concentrations ranged from < 5.0 to 61.2 pg/ml, while progesterone concentrations were low in all animals (< 0.6 ng/ml). No corpora lutea were seen on ovarian histology. The most immature mammary glands contained multilayered ducts frequently ending in distinctive terminal end bud structures. Transitional ducts had variably stratified columnar epithelium, often with prominent rounded myoepithelial cells and loose periductal stroma. Mature ducts had simple cuboidal luminal epithelium, flattened myoepithelium, and associated lobular development, typical of the premenopausal breast. Expression of estrogen receptor alpha was significantly higher in immature ducts compared to mature ducts, while progesterone receptor expression, epithelial proliferation, and cytokeratin expression did not show a relationship to the maturity of the ducts. These findings identify dynamic morphologic changes occurring in the primate breast during early puberty and suggest that estradiol (rather than progesterone) is the predominant hormonal stimulus for early ductal and lobular development.     

The use of toxicokinetic data in preclinical safety assessment: a toxicologic pathologist perspective

Collection of toxicokinetic data has become a routine practice during the last 15 years in most general toxicity studies on pharma. It enables the correlation of pathological changes with the plasma concentration of drugs and/or their metabolites. This overview summarizes the use of the toxicokinetic data from the perspective of the toxicologic pathologist.     

The toxicity of very prolonged courses of PEGasparaginase or Erwinia asparaginase in relation to asparaginase activity,with a special focus on dyslipidemia

We prospectively studied the incidence and clinical course of hypertriglyceridemia and hypercholesterolemia during very prolonged use of asparaginase in relation to levels of asparaginase activity in children with acute lymphoblastic leukemia. We also evaluated the incidence of pancreatitis, thrombosis, hyperammonemia and central neurotoxicity and their association with asparaginase activity levels. Eighty-nine patients were treated according to the Dutch Childhood Oncology Group Acute Lymphoblastic Leukemia 10 medium-risk intensification protocol, which includes 15 doses of PEGasparaginase (2,500 IU/m²) over 30 weeks. Erwinia asparaginase (20,000 IU/m²) was administered when allergy to or silent inactivation of PEGasparaginase occurred. Triglyceride, cholesterol and ammonia levels increased rapidly in children treated with PEGasparaginase and remained temporarily elevated, but normalized after administration of the last asparaginase dose. Among the patients treated with PEGasparaginase, hypertriglyceridemia and hypercholesterolemia (grade 3/4) were found in 47% and 25%, respectively. The correlation between PEGasparaginase activity levels and triglyceride levels was strongest at week 5 (Spearman correlation coefficient=0.36, P=0.005). The triglyceride levels were higher in children ≥10 years old than in younger patients (<10 years old) after adjustment for type of asparaginase preparation: median 4.9 mmol/L versus 1.6 mmol/L (P<0.001). In patients receiving Erwinia asparaginase, triglyceride levels increased in the first weeks as well, but no grade 3/4 dyslipidemia was found. Hyperammonemia (grade 3/4) was only found in patients treated with Erwinia asparaginase (9%). Thrombosis occurred in 4.5%, pancreatitis in 7%, and central neurotoxicity in 9% of patients using either of the two agents; these toxicities were not related to levels of asparaginase activity or to triglyceride levels. In conclusion, severe dyslipidemia occurred frequently, but was temporary and was not associated with relevant clinical events and should not, therefore, be considered a reason for modifying asparaginase treatment. Dyslipidemia was the only toxicity related to levels of asparaginase activity.     

Competencies of specialised wound care nurses: a European Delphi study

Health care professionals responsible for patients with complex wounds need a particular level of expertise and education to ensure optimum wound care. However, uniform education for those working as wound care nurses is lacking. We aimed to reach consensus among experts from six European countries as to the competencies for specialised wound care nurses that meet international professional expectations and educational systems. Wound care experts including doctors, wound care nurses, lecturers, managers and head nurses were invited to contribute to an e‐Delphi study. They completed online questionnaires based on the Canadian Medical Education Directives for Specialists framework. Suggested competencies were rated on a 9‐point Likert scale. Consensus was defined as an agreement of at least 75% for each competence. Response rates ranged from 62% (round 1) to 86% (rounds 2 and 3). The experts reached consensus on 77 (80%) competences. Most competencies chosen belonged to the domain ‘scholar’ (n = 19), whereas few addressed those associated with being a ‘health advocate’ (n = 7). Competencies related to professional knowledge and expertise, ethical integrity and patient commitment were considered most important. This consensus on core competencies for specialised wound care nurses may help achieve a more uniform definition and education for specialised wound care nurses.