Qualification of a 17β-estradiol (E2) Assay in Sprague Dawley Rat Serum

Introduction/Objective

Significant technical issues are associated with methods used for the measurement of estradiol.The objective of this study was to qualify an electrochemiluminescent (ECL) assay for the quantification of 17β-estradiol (E2) in rat serum. Hemolysis has been identified as a factor that interferes with accurate measurement.The impact of hemolysis was also assessed.

Methods

Approximately 1.0 mL of whole blood was collected from male and female rats into separate red top tubes and processed to serum.

The LoQ for E2 was evaluated by analyzing the low calibrator or at least 6 serum samples diluted to produce a value at the low end of the reportable range 8 times in the same run.The mean, standard deviation, and %CV were calculated for each sample.The data set was analyzed by plotting the data and determining the concentration at the intersection of the precision profile curve.

Linearity of dilution was performed using commercially available calibration verification material and E2 stripped rat serum.The correlation coefficient, the slope, and the % Nominal were calculated.

Intra assay precision was evaluated by analyzing 8 consecutive times in a single run one rat serum sample that was not diluted or spiked. This analysis was performed during the evaluation of the LoQ.The mean, SD and %CV were calculated.

The interference of hemolysis with the E2 assay was tested by analyzing at least 5 rat serum samples/pools spiked with hemolyzed rat serum at different hemoglobin concentrations.The %RE was calculated.

Results

The LoQ assays were acceptable. For all samples tested, the % CV was less than or equal to 25%.The LoQ was verified to be 8.50 pg/mL. The %CV was 15.6%. For samples with estradiol concentrations below the LoQ, a value of 4.25 pg/ml was reported.

Linearity of dilution for E2 was acceptable.The correlation coefficients were greater than or equal to 0.9000, the slopes were between 0.7500 and 1.2500, and the % nominals for each level were between 75-125%.

The intra-assay precision was considered acceptable with a %CV of 8.6%.

There was no hemolysis interference in the assay when samples were spiked with hemoglobin concentrations of up to 70 mg/dL, based on the %RE of less than or equal to 25% of non-hemolyzed samples.

Conclusion

Qualification of the ECL method, demonstrates the assay is suitable for the determination of E2 in serum samples from rats and absence of hemolysis interference up to 70 mg/dL of hemoglobin concentration.

Effective encapsulation and biological activity of phosphorylated chemotherapeutics in calcium phosphosilicate nanoparticles for the treatment of pancreatic cancer

Drug resistant cancers like pancreatic ductal adenocarcinoma (PDAC) are difficult to treat, and nanoparticle drug delivery systems can overcome some of the limitations of conventional systemic chemotherapy. In this study, we demonstrate that FdUMP and dFdCMP, the bioactive, phosphorylated metabolites of the chemotherapy drugs 5-FU and gemcitabine, can be encapsulated into calcium phosphosilicate nanoparticles (CPSNPs). The non-phosphorylated drug analogs were not well encapsulated by CPSNPs, suggesting the phosphate modification is essential for effective encapsulation. In vitro proliferation assays, cell cycle analyses and/or thymidylate synthase inhibition assays verified that CPSNP-encapsulated phospho-drugs retained biological activity. Analysis of orthotopic tumors from mice treated systemically with tumor-targeted FdUMP-CPSNPs confirmed the in vivo up take of these particles by PDAC tumor cells and release of active drug cargos intracellularly. These findings demonstrate a novel methodology to efficiently encapsulate chemotherapeutic agents into the CPSNPs and to effectively deliver them to pancreatic tumor cells.

Blebbistatin-Loaded Poly(d,l-lactide-co-glycolide) Particles For Treating Arthrofibrosis

Joint immobility is a debilitating complication of articular trauma that is characterized by thickening and stiffening of the joint capsule and the formation of fibrotic lesions inside joints. Capsule release surgery can temporarily restore mobility, but contraction often recurs due to the contractile activities of fibroblasts, which exert tension on the capsule ECM via nonmuscle myosin II. Based on these findings we hypothesized that blebbistatin, a drug that reversibly inhibits the activity of this protein, would relax ECM tension imposed by fibroblasts and reduce fibrosis. In this study, we characterized the effectiveness of blebbistatin as an anticontractile treatment. Given that sustained suppression of contractile activity may be required to achieve capsule release and reduce fibrosis, we compared the effects on fibroblast-mediated collagen ECM displacement of blebbistatin-loaded poly(lactide-co-gylcolide) (PLGA) particles versus bolus blebbistatin dosing. Time-lapse imaging of fluorescent microspheres embedded in collagen gels confirmed that PLGA/blebbistatin inhibited force generation and reduced both gel displacement and rate of displacement. In addition, collagen production at 10 days was significantly reduced. Taken together, these data indicate that blebbistatin-loaded PLGA particles can be used to inhibit fibroblast force-generation and reduce collagen production and lay the foundation for optimization of drug delivery technology for treating arthrofibrosis.

Undetectable pregnancy-associated plasma protein-A in antenatal serum Down's syndrome screening: a case of assay interference

Serum pregnancy-associated plasma protein-A (PAPP-A) is measured in Down's syndrome screening, routinely offered to women in pregnancy. We present the case of an undetectable pregnancy-associated plasma protein-A concentration on the PerkinElmer AutoDELFIA system where immunoassay interference was suspected. Investigations performed, including dilution and recovery studies and antibody-blocking tube incubations, all yielded serum pregnancy-associated plasma protein-A concentrations of <25 mU/L. Pregnancy-associated plasma protein-A was also undetectable on two alternative pregnancy-associated plasma protein-A assays. An experimental manual Delfia procedure suggested the site of interference was between the secondary antibody and the pregnancy-associated plasma protein-A molecule. This case of negative interference in the PerkinElmer pregnancy-associated plasma protein-A assay produced a falsely high Down's syndrome risk that might have led to an unnecessary invasive procedure with the potential for fetal loss. This highlights the need for Down's syndrome screening laboratories to be vigilant to immunoassay interference due to the significant impact of the results on patient decision outcome.

Assessment of Bradykinesia in Parkinson's disease patients through a multi-parametric system

The aim of this paper is to describe and present the results of the automatic detection and assessment of bradykinesia in motor disease patients using wireless, wearable accelerometers. The current work is related to a module of the PERFORM system, a FP7 project from the European Commission, that aims at providing an innovative and reliable tool, able to evaluate, monitor and manage patients suffering from Parkinson's disease. The assessment procedure was carried out through a developed C# library that detects the activities of the patient using an activity recognition algorithm and classifies the data using a Support Vector Machine trained with data coming from previous test phases. The accuracy between the output of the automatic detection and the evaluation of the clinician both expressed with the Unified Parkinson's disease Rating Scale, presents an average value of [68.3 ± 8.9]%. A meta-analysis algorithm is used in order to improve the accuracy to an average value of [74.4 ± 14.9]%. Future work will include a personalized training of the classifiers in order to achieve a higher level of accuracy.

Cytoskeletal dissolution blocks oxidant release and cell death in injured cartilage

The mechanisms by which articular surface impact causes post-traumatic osteoarthritis are not well understood, but studies of cartilage explants implicate the mitochondrial electron transport chain as a source of oxidants that cause chondrocyte death from mechanical injury. The linkage of mitochondria to the cytoskeleton suggests that they might release oxidants in response to mechanical strain, an effect that disrupting the cytoskeleton would prevent. To test this we investigated the effects of agents that promote the dissolution of microfilaments (cytochalasin B) or microtubules (nocodazole) on oxidant production and chondrocyte death following impact injury. Osteochondral explants treated with cytochalasin B or nocodazole for 4 h were impacted (7 J/cm(2)) and stained for oxidant production directly after impact and for cell viability 24 h after impact. Surfaces within and outside impact sites were then imaged by confocal microscopy. Both agents significantly reduced impact-induced oxidant release (p < 0.05); however, cytochalasin B was more effective than nocodazole (>60% reduction vs. 40% reduction, respectively). Both agents also prevented impact induced cell death. Dissolution of the cytoskeleton by both drugs was confirmed by phalloidin staining and confocal microscopy. These findings show that chondrocyte mortality from impact injury depends substantially on mitochondrial-cytoskeletal linkage, suggesting new approaches to stem mechanically induced cartilage degeneration.

Repeated measurement of mechanical properties in viable osteochondral explants following a single blunt impact injury

The objective of this work was to develop a method for repeated same-site measurement of mechanical properties suitable for the detection of degenerative changes in a biologically active explant model after a single blunt impact injury. Focal blunt impact injuries to articular surfaces lead to local cartilage degeneration and loss of mechanical properties. We employed a repeated measurement methodology to determine variations in mechanical same-site properties before and after injury in living cartilage, with the hypothesis that normalization with initial mechanical properties may provide a clearer evaluation of impact effects and improve our understanding of the biologic responses to impact injury. Bovine osteochondral explants were cultured for up to 14 days after impact injury. Indentation tests were performed before and after impact injury to assess relative changes in mechanical properties. Creep strain increased significantly in impacted explants after 7 days and in both impacted and control explants after 14 days. Further analysis at 14 days revealed decreases in stretch factor beta, creep time constant and local compressive modulus. A repeated measures methodology reliably detected changes in the mechanical behaviour of viable osteochondral explants after a single impact injury.

Biomechanical disc culture system: feasibility study using rat intervertebral discs

A small-scale biomechanical disc culture system was designed to stimulate intervertebral disc (IVD) 'motion segment' in culture environment with load-controlled compression and combined load (compression+shear). After 7 days of diurnal mechanical loading, cell viability of discs stimulated with static compression load (0.25 MPa) and static combined load (compression (0.25 MPa)+shear (1.5N)) were similar (>90 per cent) to unloaded controls. Mechanically stimulated discs showed decrease in static/dynamic moduli, early stress relaxation, and loss of disc height after 7 days of diurnal loading. Histological data of discs indicated load-induced transformations that were not apparent in controls. The feasibility of studying the mechanobiology of intact IVD as a motion segment was demonstrated. Media conditioning (improve tissue stability in long-term culture) and application of biochemical gene expression assays (differential tissue response to types of mechanical stimulation) are proposed as future improvements. The study suggests that the limitations in studying mechanobiology of IVD pathology in vitro can be overcome and it is possible to understand the physiologically relevant mechanism of IVD pathology.

Rotenone prevents impact-induced chondrocyte death

Mechanical insult to articular cartilage kills chondrocytes, an event that may increase the risk of posttraumatic osteoarthritis. Recent reports indicate that antioxidants decrease impact-induced chondrocyte death, but the source(s) of oxidants, the time course of oxidant release, and the identity of the oxidative species generated in response to injury are unknown. A better understanding of these processes could lead to new treatments of acute joint injuries. To that end, we studied the kinetics and distribution of oxidant production in osteochondral explants subjected to a single, blunt-impact injury. We followed superoxide production by measuring the time-dependent accumulation of chondrocyte nuclei stained with the superoxide-sensitive probe dihydroethidium. The percentage of chondrocytes that were dihydroethidium-positive was 35% above baseline 10 min after impact, and 65% above baseline 60 min after impact. Most positive cells were found within and near areas contacted directly by the impact platen. Rotenone, an electron transport chain inhibitor, was used to test the hypothesis that mitochondria contribute to superoxide release. Rotenone treatment significantly reduced dihydroethidium staining, which remained steady at 15% above baseline for up to 60 min postimpact. Moreover, rotenone reduced chondrocyte death in impact sites by more than 40%, even when administered 2 h after injury (p < 0.001). These data show that much of the acute chondrocyte mortality caused by in vitro impact injuries results from superoxide release from mitochondria, and suggest that brief exposure to free radical scavengers could significantly improve chondrocyte viability following joint injury.

The effect of incongruent instructions and consequences on imitation in retarded children

Three retarded boys served as subjects in a 13-phase experiment. In eight of these phases, the instructions administered by the experimenter before demonstrating a behavior and the consequences for imitative behavior were incongruent (the consequences were not those indicated by the instructions). Consequences rather than instructions controlled imitative behavior when (a) subjects were instructed not to imitate but received reinforcers if they imitated; (b) subjects were instructed to imitate but were differentially reinforced for other behavior; (c) subjects were instructed to imitate but were verbally reprimanded for imitation. Although subjects were highly imitative at the beginning of the study, when there was no reinforcement for imitation subjects gradually stopped imitating when instructed not to imitate. Instructions seemed to control imitative behavior when there was no reinforcement for imitation and subjects were instructed to imitate. These results indicated a need for further investigation of antecedent and consequent variables in imitation experiments and pointed out that certain techniques may be more efficient than others in eliminating well-established responses.

[Five years of renal trauma in a paediatric trauma center: new tools in the diagnostic and therapeutic process]

INTRODUCTION

There is general agreement in the conservative management of most renal traumas, but questions like the role of angiography are still controversial. Our objective is to review the paediatric renal trauma characteristics, propose a therapeutic protocol and suggest new therapeutic tools.

MATERIAL AND METHODS

Retrospective review of clinical records (epidemiology, diagnostic methods, renal injury grade according to the AAST Organ Injury Scale, treatment and follow up) of the paediatric renal injuries at Vail d'Hebron Hospital in the last 5 years. Outline of a diagnostic-therapeutic protocol consistent with the literature.

RESULTS

Since 2001, 18 cases of paediatric renal trauma have been diagnosed. Median of age was 10 years (range 2-17). Renal injury grade was: I (4), II (5), III (4), IV (4), V (1). Main mechanisms of injury were car and motorcicle accidents (4), fall (3), bicycle (3) and sports (3). There were different severity associated injuries in 10 patients. Abdominal exploration was normal in 6 cases, and in 5 (including the grade V injury) hematuria was absent or was microscopic. Mean hematocrit and hemoglobine were 34.5% y 11.8 g/dl. Abdominal CT was performed in all cases, detecting injuries that were unnoticed with ultrasound exploration. Complications were: renal artery pseudoaneurism (1), urinoma (1), uretero-pelvic joint disruption (1), arterial hypertension (3), renal colic (1). Management was: conservative in 13 cases, angiography in 4 (2 embolizations of bleeding vessels, 1 pseudoaneurism embolization, 1 placement of endovascular stents in an injury of the arterial intima), delayed surgery in 2 (1 nefrectomy, 1 uretero-pyeloplasty). All of them received prophylactic antibiotics; 10 had self-limited fever with negative cultures. Only in 2 cases DMSA at 6 months was inferior to 20%. There were no deaths.

CONCLUSIONS

In paediatric patients, there can be severe renal injuries despite absence of hematuria and a normal physical exam and hemogram. Abdominal CT with endovenous contrast is the keystone of diagnosis, and identifies vascular injuries that might need immediate treatment, like renal ischemia. Angiography is an important tool to consider in case of persistent bleeding or renal infarctation.

Rate of acute adverse events for narrow-band UVB and Psoralen-UVA phototherapy

BACKGROUND

Ultraviolet (UV) radiation therapies are commonly used to treat a wide range of dermatological conditions. However, no published data exist regarding the rate of acute adverse events occurring within the different UV therapy modalities.

AIM

The aim of this study was to determine the rate of acute adverse events experienced by patients receiving narrow-band UVB or photochemotherapy in 3 neighboring dermatology units.

METHOD

Standardized adverse event forms from all 3 units were retrospectively analysed over a 12-month period between October 2003 and September 2004. The treatments included were narrow-band UVB and systemic, bath and hand/foot PUVA.

RESULTS

A total of 8784 treatments were given over the study period. The total number of acute adverse events recorded for all phototherapy treatments was 70 (0.8%). The rates of acute adverse events for each treatment modality were 0.6% for narrow-band UVB, 1.3% for systemic PUVA, 1.3% for bath PUVA and 0.8% for hand/foot PUVA. Adverse events were due to patient non-compliance with standard operating procedures in 15 cases (21%) and operator error in 2 (3%). Only 4 of the acute adverse events were considered to be severe, accounting for 0.05% of all treatments.

CONCLUSIONS

The rates of acute adverse events with phototherapy in this analysis were low, in particular the rate of severe adverse events. The highest rate was seen with both systemic and bath PUVA. The number of adverse events resulting from operator error was low. These published rates for adverse events associated with narrow-band UVB and PUVA may help other units when analyzing their own rate of adverse events.

Antioxidants block cyclic loading induced chondrocyte death

Articular cartilage in congruous joints benefits from the moderate stresses and strains associated with normal cyclic loading. However, loading of joints with surface incongruities can lead to local stress and strain elevation at "step-off' sites where cartilage is not fully buttressed b ysurrounding matrix. Excessive stresses and strains predicted to occur at such sites may induce apoptosis, a process thought to promote cartilage degeneration and osteoarthritis (OA) through chondrocyte attrition. We hypothesized that the induction of apoptosis is mediated by oxidants, and that antioxidants can reduce elevated stress-induced chondrocyte attrition. To test this we exposed cylindrical cartilage explants from human articular cartilage to radially unconfined cyclic axial compression (3600 cycles, 1 Hz, 50% duty cycle) using two different physiologic loads (2MPa and 5 MPa). We found that 30% of chondrocytes in the superficial zone died within 24 hours of exposure to loading with 5 MPa axial compression, whereas mortality was limited to less than 15% with 2 MPa axial compression. Similarly, lactate accumulation in the medium was suppressed by compression with 5 MPa, but not 2 MPa. Approximately 80% of cell death induced by 5 MPa compression was blocked by pre-incubation of the explants in a variety of anti-oxidants including vitamin E, n-acetyl cysteine (NAC), and a superoxide dismutase mimetic (SOD). SOD and NAC also prevented the suppression of lactate secretion after 5 MPa compression. These observations support the hypothesis that the harmful effects of abnormal cyclic loading are mediated by oxidants and suggest that treatments to prevent OA may include methods of minimizing oxidative damage to chondrocytes.

Post-traumatic osteoarthritis: the role of stress induced chondrocyte damage

Post-traumatic osteoarthritis is the form of osteoarthritis (OA) that develops following joint injury. Although its end-stage is indistinguishable from idiopathic OA, many patients with post-traumatic OA are younger than those with idiopathic OA, and they have a well-defined precipitating insult. Clinical and experimental studies suggest that excessive acute impact energy or chronic mechanical overload cause the degeneration of the articular surface responsible for post-traumatic OA. Yet, the mechanisms by which excessive mechanical force causes OA remain unknown. For these reasons it has not been possible to develop effective methods of preventing or decreasing the risk of post-traumatic OA. We hypothesized that mechanical loading that exceeds the tolerance of the articular surface causes chondrocyte damage due to oxidative stress. Our in vitro tests of human articular cartilage samples showed that shear stress causes chondrocyte death and that anti-oxidants decrease the shear stress induced cell death. These observations suggest that specific patterns of loading are particularly damaging to articular surfaces and that improved treatments of joint injuries may include mechanical methods of minimizing shear stresses and biologic methods of minimizing oxidative damage.

What can adaptive optics do for a scanning laser ophthalmoscope ?

By compensating for the aberrations in the eye that cause blur, the adaptive optics scanning laser ophthalmoscope (AOSLO) yields high-magnification, high-resolution, real-time images of the living human retina. Features as small as single cone photoreceptors can be resolved, single leukocytes are recorded in real time as they pass through the smallest retinal capillaries, and the optical sectioning capability can be used to visualize independent layers of the retinal tissue ranging from the nerve fiber layer, through the blood vessels to the photoreceptors. The use of AO technology not only enhances the breadth of applications of conventional SLOs, but it facilitates a host of new applications. Here we provide an overview of AOSLO performance and its applications, including two clinical examples. Finally, we preview two novel applications; one where the AOSLO is used to present AO-corrected stimuli directly onto the retina while simultaneously recording their exact retinal position, and a second application where AOSLO videos are used to provide very precise, high-frequency measures of eye movements.

Percutaneous Ultrasound-Guided Pancreas Allograft Biopsy: A Single-Center Experience

Percutaneous ultrasound-guided pancreas allograft biopsy is the preferred technique for evaluating pancreas allograft rejection. Experience from large centers has shown it to be safe and effective. We report our experience with 120 percutaneous allograft biopsies performed at a single center. Biopsy tissue was obtained in 54 patients. Thirty-three patients received simultaneous pancreas and kidney transplants, 14 received isolated pancreas transplants, and 7 received a pancreas transplant after kidney transplantation. Biopsies were performed by pancreas transplantation surgeons with the assistance of radiologists under ultrasound guidance using an Acuson XP 128/10 ultrasound machine. One hundred twenty allograft biopsies were performed in 54 patients. Twenty-seven (50%) patients underwent multiple biopsies. In 102 (85%) biopsies the specimens were adequate for examination. Eighteen (15%) biopsy samples had no pancreatic tissue and showed surrounding fat and small bowel. 1 (1.8%) patient bleeding developed that required transfusion of 3 units of packed red blood cells, but no surgical intervention was necessary. One (1.8%) patient had a pancreatic fistula, which healed with nonoperative management. Biochemical evidence of pancreatitis was noted in 5 (9.2%) patients, but none of these patients had clinical signs of pancreatitis. Percutaneous ultrasound-guided pancreas allograft biopsy is a safe procedure with a low complication rate and a high tissue yield for histopathologic examination.

Peristomal allergic contact dermatitis - case report and review of the literature

Allergic contact dermatitis (ACD) is a rare cause of peristomal skin problems. Only 23 cases have previously been reported in the literature. We report the case of a colostomy patient with a severe disabling blistering peristomal dermatitis. Patch testing to a British Contact Dermatitis Society standard series, medicaments and a plastics and glues series was negative. Patch testing to the patient's own products gave a positive reaction (+) at D2 and D4 to Dansac soft paste and Stomahesive paste. Further patch testing to the components of Dansac soft paste showed a positive (+) reaction at D2 and D4 to ester of polymethyl vinyl/maleic acid copolymer (Gantrez-ES) only. This is the first reported case of ACD due to Dansac soft paste. ACD to Gantrez has previously been reported but in different products. We also review the other previously reported cases of ACD causing peristomal dermatitis and stress the importance of patch testing in these cases, in particular to the patient's own products, as avoidance of identified allergens can have a large impact on the quality of life.

'Black henna' tattoos: an occult source of natural rubber latex allergy?

Temporary 'black henna' tattoos are an increasingly popular body decoration with a growing incidence of associated adverse events. We report the case of a 14 year old girl presenting with an acute allergic contact dermatitis to hair dyes. Some years previously she had a 'black henna' tattoo with prior application of a tacky transfer to the skin to outline the design followed some days later by an acute localised blistering reaction. Patch testing to an extended British Contact Dermatitis Society standard series showed relevant positive reactions to paraphenlyenediamine (PPD) and thiuram mix, as well as to several of the azo disperse dyes. We went on to perform prick testing to natural rubber latex (NRL), showing a positive reaction to the commercial HEP 100 concentration. We propose that through the initial acute reaction caused by PPD in the 'black henna' our patient was not only sensitized to PPD, but also to thiuram and natural rubber latex which may have been present in the tacky transfer applied prior to 'tattooing.' We would add that temporary 'black henna' tattoos may have more important consequences than previously thought on patients' future health by sensitization to NRL.

HIV infection presenting with duodenal tuberculosis

Extrapulmonary tuberculosis is a protean and often difficult to recognise infection. Gastrointestinal tuberculosis is a rare condition that mainly occurs in immunodeficient people. We report a case of duodenal tuberculosis, which presented with gastrointestinal symptoms, anaemia and hyponatraemia, in a patient with previously undiagnosed HIV infection.

Seventeen-year survivorship analysis of silastic metacarpophalangeal joint replacement

We reviewed the records and radiographs of 381 patients with rheumatoid arthritis who had undergone silastic metacarpophalangeal joint replacement during the past 17 years. The number of implants was 1336 in the course of 404 operations. Implant failure was defined as either revision or fracture of the implant as seen on radiography. At 17 years, the survivorship was 63%, although on radiographs two-thirds of the implants were seen to be broken. Factors which improved survival included soft-tissue balancing, crossed intrinsic transfer and realignment of the wrist. Surgery to the thumb and proximal interphalangeal joint had a deleterious effect and the use of grommets did not protect the implant from fracture.