Although vaccination rates have increased, problems still remain in the storage and handling of vaccines. This study focused on inspecting actual vaccine storage status and awareness, and comparing them before and after education was provided.
In the primary inspection, a status survey checklist was completed by visual inspection. A questionnaire on the awareness of proper vaccine storage and handling was also administered to vaccine administrators in private medical institutions in 4 regions in Gyeongsangbuk-province. One-on-one education was then carried out, and our self-produced manual on safe vaccine storage and management methods was provided. In the secondary inspection, the investigators visited the same medical institutions and used the same questionnaire and checklist used during the primary inspection. The results before and after education were compared, by treating each appropriate answer as 1 point.
The average checklists score was 9.74 (out of 15 points), which increased significantly after education was provided (by 0.84, p<0.001). The participants demonstrated improved practices in recording storage temperatures (p=0.016), storing vaccines in the center of the refrigerator (p=0.004), storing vaccines with other medication and non-medical items (p=0.031) after education. The average score calculated from the questionnaires was 10.48 (out of 14 points), which increased after education (by 1.03, p<0.001).
This study suggests that vaccine storage practices and awareness are inadequate, but can be partially improved by providing relevant education. Repetitive education and policy-making are required to store vaccines safely because one-off education and unenforced guidelines offer limited efficacy.
Awareness; Checklist; Education; Questionnaires; Vaccines
Platelets are central players in inflammation and are an important component of the innate immune response. The ability to visualize platelets within the live host is essential to understanding their role in these processes. Past approaches have involved adoptive transfer of labelled platelets, non-specific dyes, or the use of fluorescent antibodies to tag platelets in vivo. Often, these techniques result in either the activation of the platelet, or blockade of specific platelet receptors. In this report, we describe two new methods for intravital visualization of platelet biology, intravenous administration of labelled anti-CD49b, which labels all platelets, and CD41-YFP transgenic mice, in which a percentage of platelets express YFP. Both approaches label endogenous platelets and allow for their visualization using spinning-disk confocal fluorescent microscopy. Following LPS-induced inflammation, we were able to measure a significant increase in both the number and size of platelet aggregates observed within the vasculature of a number of different tissues. Real-time observation of these platelet aggregates reveals them to be large, dynamic structures that are continually expanding and sloughing-off into circulation. Using these techniques, we describe for the first time, platelet recruitment to, and behaviour within numerous tissues of the mouse, both under control conditions and following LPS induced inflammation.
More than 2 million persons are incarcerated in the United States. Most are young minority men, soon to reenter the community. The majority are also lifelong smokers with high rates of health-related problems. As prisons implement smoking bans, it is not known whether health behavior change that is mandated, rather than selected, can be maintained. The Wisconsin Department of Corrections smoking ban is a unique opportunity to investigate determinants of smoking behavior after release from prison.
A convenience sample of 49 incarcerated men near release participated in two interviews (1-month prerelease, in prison, and 1-month postrelease via telephone). Descriptive analyses and multivariate modeling were conducted to determine associations with postrelease smoking.
Participants had a mean age of 36.7 years, 12.4 years of education, and a 2.3-year incarceration; 47% were Black and 41% White. They had smoked 14.5 years. Most (67%) believed that their health was improved after the smoking ban. Paired t tests revealed decreases in Positive and Negative Affect Scale negative affect (p = .001) and Patient Health Questionnaire-8 depression (p = .009) postrelease. Univariate analysis showed correlations of intent to smoke upon release with smoking relapse postrelease (p = .001), White race with smoking relapse postrelease (p = .045), and perceived better health since the prison smoking ban with nonsmoking on release (p = .01). There was a trend toward use of alcohol with smoking relapse on release (p = .061).
Prerelease smoking intention predicted postrelease behavior. Belief in improved health after the prison smoking ban correlated with nonsmoking on release. Targeted relapse prevention interventions are needed for people reentering the community.
To investigate the feasibility of using a record linkage method for identifying vaccine attributable adverse events, computerized hospital admissions and vaccination records from South East Kent district were linked and checked for accuracy. Records for 90% of children under 2 years of age admitted to hospital over a 2-year period were matched with vaccination records using a computer algorithm based on name, date of birth, sex, and post-code supplemented by visual inspection. Relative to this gold standard, matching on date of birth, sex and postcode alone had a sensitivity of 60% and an incorrect match rate of 0.2% after matches to more than one vaccine recipient were excluded. Manual checking of a sample of admissions showed that only 4% had been assigned incorrect International Classification of Disease (ICD) codes. Routine record linkage of ICD admission codes to vaccination records therefore yields data of good quality which may be used for surveillance purposes.
Although most researchers agree that platelet-rich plasma (PRP) is a good source of autogenous growth factors, its effect on bone regeneration is still controversial. The purpose of this study was to evaluate whether increasing angiogenic factors in the human PRP to enhance new bone formation through rapid angiogenesis.
MATERIAL AND METHODS
In vitro, the human platelets were activated with application of shear stress, 20 µg/ml collagen, 2 mM CaCl2 and 10U thrombin/1 × 109 platelets. Level of vascular endothelial growth factor (VEGF) and platelet microparticle (PMP) in the activated platelets were checked. In the animal study, human angiogenic factors-enriched PRP was tested in 28 athymic rat's cranial critical bone defects with β-TCP. Angiogenesis and osteogenesis were evaluated by laser Doppler perfusion imaging, histology, dual energy X-ray densinometry, and micro-computed tomography.
In vitro, this human angiogenic factors-enriched PRP resulted in better cellular proliferation and osteogenic differentiation. In vivo, increasing angiogenic potential of the PRP showed significantly higher blood perfusion around the defect and enhanced new bone formation around acellular bone graft material.
Angiogenic factor-enriched PRP leads to faster and more extensive new bone formation in the critical size bone defect. The results implicate that rapid angiogenesis in the initial healing period by PRP could be supposed as a way to overcome short term effect of the rapid angiogenesis.
Platelet-rich plasma; Angiogenesis; Human; Athymic rat; Cranial defect
The study of platelet aggregation is essential to assess in vitro platelet function by different platelet activation pathways.
To assess aggregation and biochemical parameters of random platelet concentrates produced at the Fundação HEMOAM using the quality control tests defined by law.
Whole blood samples from 80 donors and the respective platelet concentrate units were tested. Platelet concentrates were tested (platelet count, aggregation and pH) on days 1, 3 and 5 of storage. Additionally a leukocyte count was done only on day 1 and microbiological tests on day 5 of storage. Collagen and adenosine diphosphate were used as inducing agonists for platelet aggregation testing.
Donor whole blood had normal aggregation (aggregation with adenosine diphosphate = 67% and with collagen = 78%). The median aggregation in platelet concentrates with adenosine diphosphate was low throughout storage (18% on day 1, 7% on day 3 and 6% on day 5) and the median aggregation with collagen was normal only on day 1 and low thereafter (54.4% on day 1, 20.5% on day 3 and 9% on day 5).
Although the results were within the norms required by law, platelet concentrates had low aggregation rates. We suggest the inclusion of a functional assessment test for the quality control of platelet concentrates for a more effective response to platelet replacement therapy.
Hemostasis; Quality control; Collagen; Blood component transfusion; Blood banks; Platelet aggregation
The interaction of group A streptococcal lipoteichoic acid (LTA) with mammalian cell membranes was studied in human platelets. The binding of LTA to platelets was platelet concentration and time dependent. Binding approached a maximum within 10 min of incubation. The bound LTA could be displaced by adding a 50-fold excess of unlabeled LTA. An association constant of 1.9 X 10(-7) M was calculated, and only one population of binding sites was detected. Immuno-ferritin labeling of LTA-treated platelets demonstrated a patchy distribution of LTA binding sites on the platelet surface. LTA inhibited collagen- and alpha1 chain-induced platelet aggregation, but not the platelet release reaction, suggesting that the LTA and collagen binding sites on human platelets are distinct. Apparently, LTA binds to platelets and interferes with collagen-induced aggregation although collagen is still able to attach to binding sites to trigger the release reaction.
The diagnosis of caries lesions is still a matter of concern in dentistry. The diagnosis of dental caries by digital radiography has a number of advantages over conventional radiography; however, this method has not been explored fully in the field of paediatric dentistry. This in vitro research evaluated the accuracy of direct digital radiography compared with visual inspection and conventional radiography in the diagnosis of occlusal caries lesions in primary molars.
50 molars were selected and evaluated under standardized conditions by 2 previously calibrated examiners according to 3 diagnostic methods (visual inspection, conventional radiography and direct digital radiography). Direct digital radiographs were obtained with the Dixi3 system (Planmeca, Helsinki, Finland) and the conventional radiographs with InSight film (Kodak Eastman Co., Rochester, NY). The images were scored and a reference standard was obtained histologically. The interexaminer reliability was calculated using Cohen's kappa test and the specificity, sensitivity and accuracy of the methods were calculated.
Examiner reliability was good. For lesions limited to the enamel, visual inspection showed significantly higher sensitivity and accuracy than both radiographic methods, but no significant difference was found in specificity. For teeth with dentinal caries, no significant differences were found for any parameter when comparing visual and radiographic evaluation.
Although less accurate than the visual method for detecting caries lesions confined to the enamel, the direct digital radiographic method is as effective as conventional radiographic examination and visual inspection of primary teeth with occlusal caries when the dentine is involved.
direct digital radiography; conventional radiography; dental caries; primary teeth
Platelet gel is being ever more frequently used to promote healing of cutaneous ulcers. However, the factors that determine the often variable clinical outcome of this procedure are still incompletely understood.
The aims of this study were to demonstrate that platelet gel, even when obtained under strictly controlled conditions, produces highly variable outcomes in patients with cutaneous ulcers and to propose a method for in vitro standardisation of the biological properties of platelet gel.
Material and methods.
Patients were enrolled on the basis of a pre-defined protocol. Platelet concentrate was produced with standard methods, with a variability in platelet count among the different samples of less than 10%. The platelet gel for clinical use was obtained, under strictly standardized conditions, by adding thrombin and calcium gluconate to the concentrates. For in vitro studies, platelet gel, obtained from platelet-rich plasma from four donors, was frozen and thawed twice so as to increase gel contraction. The supernatant was used to modify cell proliferation, protein synthesis, and the expression of selected genes in cultures of human diploid fibroblasts.
Seventeen patients (aged 44–78 years) with ulcers (4 diabetic, 11 vascular, 1 post-traumatic, 1 decubitus) were treated with platelet gel (4 autologous, 13 homologous). Complete re-epithelialisation of four ulcers (1 diabetic, 1 post-traumatic, 2 vascular) was obtained after applications of platelet gel (2 autologous, 2 homologous); in 11 other cases there was a greater than 50% reduction in the size of the ulcer. Two patients had no benefit. The supernatant of the platelet gel was able to promote dose-dependent proliferation and changes in gene expression as well as in metabolic activities related to protein synthesis.
Although the use of platelet gel in the treatment of cutaneous ulcers is increasing, and conditions for its production are better standardised, very considerable variability of clinical outcomes is still observed, even within single centres, suggesting that there are differences in biological properties of platelet concentrates from individual patients which cannot be readily controlled with current techniques. The biological effects of the platelet gel supernatant described in this article may provide the basis for a simple biological validation of platelet preparations before their clinical use, so as to reduce this potentially important source of variability.
platelet gel; fibroblasts; ulcers; cell proliferation
Manufacturing defects of endotracheal tube (ETT) are still encountered in anesthesia practice. Many such defects go unnoticed during routine inspection prior to their use. Such defects in ETT may lead to partial or complete airway obstruction in an intubated patient. We report a case of partial airway obstruction with a prepacked, single use, uncuffed ETT due to a manufacturing defect in the form of a plastic meniscus at the distal end of the tube. This case report highlights the significance of standard monitoring of ventilation and the role of a vigilant clinician in detecting such defects in avoiding critical events as can arise from the use of such defective ETTs. It also emphasizes the need for double checking ETTs prior to their use.
Endotracheal tube; ventilation; monitoring; intubation
Maintaining data quality and integrity is important for research studies involving prospective data collection. Data must be entered, erroneous or missing data must be identified and corrected if possible, and an audit trail created.
Using as an example a large prospective study, the Missouri Lower Respiratory Infection (LRI) Project, we present an approach to data management predominantly using SAS software. The Missouri LRI Project was a prospective cohort study of nursing home residents who developed an LRI. Subjects were enrolled, data collected, and follow-ups occurred for over three years. Data were collected on twenty different forms. Forms were inspected visually and sent off-site for data entry. SAS software was used to read the entered data files, check for potential errors, apply corrections to data sets, and combine batches into analytic data sets. The data management procedures are described.
Study data collection resulted in over 20,000 completed forms. Data management was successful, resulting in clean, internally consistent data sets for analysis. The amount of time required for data management was substantially underestimated.
Data management for prospective studies should be planned well in advance of data collection. An ongoing process with data entered and checked as they become available allows timely recovery of errors and missing data.
From June 2006 to December 2007, 3,648 clinical specimens consecutively received for mycobacterial culture were investigated. Each processed sample was inoculated into Bactec MGIT 960 liquid medium and a Löwenstein-Jensen slant. Tubes that were flagged as positive by the instrument as well as those determined to be negative after 42 days of incubation were removed, visually inspected for growth, and checked for the presence of acid-fast bacilli. Three hundred sixty-nine mycobacterial strains were recovered; of the 44 Mycobacterium xenopi isolates recovered by MGIT medium, only 13 were detected by the instrument (P < 0.0001). Most tubes yielding M. xenopi exhibited a peculiar pattern of growth characterized by a scant number of round, yellow-pigmented granules instead of the fine, evenly dispersed clumps usually observed for mycobacteria. It is suggested to check all individual tubes discarded by the MGIT 960 system at the end of the incubation period to prevent a significant amount of previously undetected growth from being missed.
The oxidation of proteins by endogenously generated free radicals causes structural modifications in the molecules that lead to generation of neo-antigenic epitopes that have implications in various autoimmune disorders, including rheumatoid arthritis (RA). Collagen induced arthritis (CIA) in rodents (rats and mice) is an accepted experimental model for RA.
Hydroxyl radicals were generated by the Fenton reaction. Collagen type II (CII) was modified by •OH radical (CII-OH) and analysed by ultraviolet-visible (UV-VIS), fluorescence and circular dichroism (CD) spectroscopy. The immunogenicity of native and modified CII was checked in female Lewis rats and specificity of the induced antibodies was ascertained by enzyme linked immunosorbent assay (ELISA). The extent of CIA was evaluated by visual inspection. We also estimated the oxidative and inflammatory markers in the sera of immunized rats. A slight change in the triple helical structure of CII as well as fragmentation was observed after hydroxyl radical modification. The modified CII was found to be highly arthritogenic and immunogenic as compared to the native form. The CII-OH immunized rats exhibited increased oxidative stress and inflammation as compared to the CII immunized rats in the control group.
Neo-antigenic epitopes were generated on •OH modified CII which rendered it highly immunogenic and arthritogenic as compared to the unmodified form. Since the rodent CIA model shares many features with human RA, these results illuminate the role of free radicals in human RA.
Salvianolic acid B (SB) is an active component isolated from Danshen, a traditional Chinese medicine widely used for the treatment of cardiovascular disorders. Previous study suggested that SB might inhibit adhesion as well as aggregation of platelets by a mechanism involving the integrin α2β1. But, the signal cascades in platelets after SB binding are still not clear.
In the present study, a differential proteomic analysis (two-dimensional electrophoresis) was conducted to check the protein expression profiles of rat platelets with or without treatment of SB. Proteins altered in level after SB exposure were identified by MALDI-TOF MS/MS. Treatment of SB caused regulation of 20 proteins such as heat shock-related 70 kDa protein 2 (hsp70), LIM domain protein CLP-36, copine I, peroxiredoxin-2, coronin-1 B and cytoplasmic dynein intermediate chain 2C. The regulation of SB on protein levels was confirmed by Western blotting. The signal cascades network induced by SB after its binding with integrin α2β1 was predicted. To certify the predicted network, binding affinity of SB to integrin α2β1 was checked in vitro and ex vivo in platelets. Furthermore, the effects of SB on protein levels of hsp70, coronin-1B and intracellular levels of Ca(2+) and reactive oxygen species (ROS) were checked with or without pre-treatment of platelets using antibody against integrin α2β1. Electron microscopy study confirmed that SB affected cytoskeleton structure of platelets.
Integrin α2β1 might be one of the direct target proteins of SB in platelets. The signal cascades network of SB after binding with integrin α2β1 might include regulation of intracellular Ca(2+) level, cytoskeleton-related proteins such as coronin-1B and cytoskeleton structure of platelets.
The results of a traditional visual mold inspection were compared to a mold evaluation based on the Relative Moldiness Index (RMI). The RMI is calculated from mold-specific quantitative PCR (MSQPCR) measurements of the concentration of 36 species of molds in floor dust samples. These two prospective mold evaluations were used to classify the mold condition in 271 homes of infants. Later, the development of respiratory illness was measured in the infants living in these homes and the predictive value of each classification system was evaluated.
The binary classification of homes as either moldy or non-moldy by on-site visual home inspection was not predictive of the development of respiratory illness (wheeze and/or rhinitis) (P = 0.27). Conversely, a method developed and validated in this paper, using the RMI index fit to a logistic function, can be used to predict the occurrence of illness in homes and allows stake-holders the choice among various levels of risk.
mold-specific quantitative PCR; mold; infants; wheezing; relative moldiness index
Noncompliance with medications may have major impacts on outcomes measured in research, potentially distorting the validity of controlled clinical trials. Riboflavin is frequently used in trials as a marker of adherence. It can be combined with study medication and is excreted in urine where it fluoresces under UV light. This study compares qualitative visual inspection of fluorescence to quantitative fluorometric analysis of riboflavin concentration in its ability to detect the presence of riboflavin in urine.
Twenty-four volunteers received 0 mg, 25 mg, and 50 mg doses of riboflavin under single-blind conditions, with 20 also receiving a 100 mg dose. Five serial urine samples were collected over the following 36 hours. Quantitative measurement of riboflavin by fluorometric analysis and qualitative assessment of each sample using visual inspection were performed.
The overall false positive rate for qualitative assessment was 53%. For quantitative assessment, a riboflavin concentration of 900 ng/mL was established to classify positive samples. More than 80% of samples were positive 2 to 24 hours following ingestion of 25 mg and 50 mg, and less than 80% were positive at 36 hours. At least 95% of observations for the 100 mg dose were above 900 ng/mL at all timepoints.
Quantitative fluorometric assessment is superior to qualitative visual inspection alone in determining medication adherence. The combination of 25–50 mg of daily riboflavin and a cut-off level of 900 ng/mL allows for the acceptable sensitivity of missing detection of non-compliant participants while preserving a high level of power to detect all cases of medication compliance.
adherence; quantitative; qualitative; riboflavin; tracer
Pharmaceuticals are an integral component of health care systems worldwide, thus, regulatory weaknesses in governance of the pharmaceutical system negatively impact health outcomes especially in developing countries . Nigeria is one of a number of countries whose pharmaceutical system has been impacted by corruption and has struggled to curtail the production and trafficking of substandard drugs. In 2001, the National Agency for Food and Drug Administration and Control (NAFDAC) underwent an organizational restructuring resulting in reforms to reduce counterfeit drugs and better regulate pharmaceuticals . Despite these changes, there is still room for improvement. This study assessed the perceived level of transparency and potential vulnerability to corruption that exists in four essential areas of Nigeria's pharmaceutical sector: registration, procurement, inspection (divided into inspection of ports and of establishments), and distribution.
Standardized questionnaires were adapted from the World Health Organization assessment tool and used in semi-structured interviews with key stakeholders in the public and private pharmaceutical system. The responses to the questions were tallied and converted to scores on a numerical scale where lower scores suggested greater vulnerability to corruption and higher scores suggested lower vulnerability.
The overall score for Nigeria's pharmaceutical system was 7.4 out of 10, indicating a system that is marginally vulnerable to corruption. The weakest links were the areas of drug registration and inspection of ports. Analysis of the qualitative results revealed that the perceived level of corruption did not always match the qualitative evidence.
Despite the many reported reforms instituted by NAFDAC, the study findings suggest that facets of the pharmaceutical system in Nigeria remain fairly vulnerable to corruption. The most glaring deficiency seems to be the absence of conflict of interest guidelines which, if present and consistently administered, limit the promulgation of corrupt practices. Other major contributing factors are the inconsistency in documentation of procedures, lack of public availability of such documentation, and inadequacies in monitoring and evaluation. What is most critical from this study is the identification of areas that still remain permeable to corruption and, perhaps, where more appropriate checks and balances are needed from the Nigerian government and the international community.
Human cyclic neutropenia is characterized by severe depression of blood neutrophil levels approximately every 21 days. To investigate the mechanism of cyclic neutropenia four patients were studied with daily complete blood counts, serial bone marrow examinations, marrow reserve testing, serum muramidase determinations, DF22P granulocytokinetic studies, and, in one patient, in vivo [3H]TdR labeling. Periodogram analysis of the serial blood counts in the latter patient and visual inspection of multiple cycles in the others revealed periodic fluctuations in the levels of blood neutrophils, monocytes, lymphocytes, reticulocytes, and platelets. Rhythmic changes in the morphologic and radioisotopic studies as well as the marrow reserve tests and muramidase measurements were consonant with a mechanism of periodic failure of marrow production rather than peripheral destruction. Human cyclic neutropenia is analogous to cyclic neutropenia in the grey collie dog and may be viewed as the consequence of cyclic hematopoiesis.
Platelet adhesion and aggregation at sites of vascular injury are essential for normal hemostasis but may also lead to pathological thrombus formation, causing diseases such as myocardial infarction or stroke. Heterodimeric receptors of the integrin family play a central role in the adhesion and aggregation of platelets. In resting platelets, integrins exhibit a low affinity state for their ligands, and they shift to a high affinity state at sites of vascular injury. It has been proposed that direct binding of the cytoskeletal protein talin1 to the cytoplasmic domain of the integrin β subunits is necessary and sufficient to trigger the activation of integrins to this high affinity state, but direct in vivo evidence in support of this hypothesis is still lacking. Here, we show that platelets from mice lacking talin1 are unable to activate integrins in response to all known major platelet agonists while other cellular functions are still preserved. As a consequence, mice with talin-deficient platelets display a severe hemostatic defect and are completely resistant to arterial thrombosis. Collectively, these experiments demonstrate that talin is required for inside-out activation of platelet integrins in hemostasis and thrombosis.
The World Health Organization has clearly indentified prevention and early detection as major objectives in the control of the oral cancer burden worldwide. At the present time, screening of oral cancer and its pre-invasive intra-epithelial stages, as well as its early detection, is still largely based on visual examination of the mouth. There is strong available evidence to suggest that visual inspection of the oral mucosa is effective in reducing mortality from oral cancer in individuals exposed to risk factors. Simple visual examination, however, is well known to be limited by subjective interpretation and by the potential, albeit rare, occurrence of dysplasia and early OSCC within areas of normal-looking oral mucosa. As a consequence, adjunctive techniques have been suggested to increase our ability to differentiate between benign abnormalities and dysplastic/malignant changes as well as to identify areas of dysplasia/early OSCC that are not visible to naked eye. These include the use of toluidine blue, brush biopsy, chemiluminescence and tissue autofluorescence. The present paper reviews the evidence supporting the efficacy of the aforementioned techniques in improving the identification of dysplastic/malignant changes of the oral mucosa. We conclude that available studies have shown promising results, but strong evidence to support the use of oral cancer diagnostic aids is still lacking. Further research with clear objectives, well-defined population cohorts, and sound methodology is strongly required.
Our everyday conscious experience of the visual world is fundamentally shaped by the interaction of overt visual attention and object awareness. Although the principal impact of both components is undisputed, it is still unclear how they interact. Here we recorded eye-movements preceding and following conscious object recognition, collected during the free inspection of ambiguous and corresponding unambiguous stimuli. Using this paradigm, we demonstrate that fixations recorded prior to object awareness predict the later recognized object identity, and that subjects accumulate more evidence that is consistent with their later percept than for the alternative. The timing of reached awareness was verified by a reaction-time based correction method and also based on changes in pupil dilation. Control experiments, in which we manipulated the initial locus of visual attention, confirm a causal influence of overt attention on the subsequent result of object perception. The current study thus demonstrates that distinct patterns of overt attentional selection precede object awareness and thereby directly builds on recent electrophysiological findings suggesting two distinct neuronal mechanisms underlying the two phenomena. Our results emphasize the crucial importance of overt visual attention in the formation of our conscious experience of the visual world.
Platelet-rich plasma (PRP) has been clinically used as an easily prepared growth factor cocktail that can promote wound healing, angiogenesis, and tissue remodeling. However, the therapeutic effects of PRP are still controversial, due partly to the lack of optimized and standardized preparation protocols. We used whole blood (WB) samples to optimize the preparation protocols for PRP, white blood cell-containing (W-PRP), platelet-concentrated plasma (PCP), and noncoagulating platelet-derived factor concentrate (PFC). PRP and W-PRP were most efficiently collected by 10 min centrifugation in a 15-mL conical tube at 230–270 g and 70 g, respectively. To prepare PCP, platelets were precipitated by centrifugation of PRP at >2300 g, 90% of supernatant plasma was removed, and the platelets were resuspended. For preparation of noncoagulating PFC, the supernatant was replaced with one-tenth volume of saline, followed by platelet activation with thrombin. Platelet (before activation) and platelet-derived growth factor (PDGF)-BB (after activation) concentrations in PCP were approximately 20 times greater than those in WB, whereas PFC contained a 20-times greater concentration of platelets before platelet activation and a 50-times greater concentration of PDGF-BB without formation of a fibrin gel after platelet activation than WB. Surprisingly, total PDGF-BB content in the PFC was twice that of activated WB, which suggested that a substantial portion of the PDGF-BB became trapped in the fibrin glue, and replacement of plasma with saline is crucial for maximization of platelet-derived factors. As an anticoagulant, ethylene di-amine tetra-acetic acid disodium inhibited platelet aggregation more efficiently than acid citrate dextrose solution, resulting in higher nonaggregated platelet yield and final PDGF-BB content. These results increase our understanding of how to optimize and standardize preparation of platelet-derived factors at maximum concentrations.
While platelet adhesion to biomaterial surfaces is widely recognized to be related to adsorbed fibrinogen (Fg), it has remained controversial whether platelet adhesion is in response to the adsorbed amount or the adsorbed conformation of this protein. To address this issue, we designed a series of platelet adhesion studies to clearly separate these two factors, thus enabling us to definitively determine whether it is the amount or the conformation of adsorbed Fg that mediates platelet response. Fg was adsorbed to a broad range of surface chemistries from a wide range of solution concentrations, with the amount and conformation of adsorbed Fg determined by absorbance and circular dichroism (CD) spectropolarimetry, respectively. Platelet adhesion response was determined by lactate dehydrogenase (LDH) assay and scanning electron microscopy (SEM). Our results show that platelet adhesion is strongly correlated with the degree of adsorption-induced unfolding of Fg (r2 = 0.96) with essentially no correlation with the amount of Fg adsorbed (r2 = 0.04). Platelet receptor inhibitor studies using an RGDS peptide reduced platelet adhesion by only about 50%, and SEM results show that adherent platelets after RGDS blocking were much more rounded with minimal extended filopodia compared with the unblocked platelets. These results provide definitive proof that the conformation of adsorbed Fg is the critical determinant of platelet adhesion, not the amount of Fg adsorbed, with adsorption-induced unfolding potentially exposing two distinctly different types of platelet binding sites in Fg; one that induces platelet adhesion alone and one that induces both platelet adhesion and activation.
We conducted studies in Vanuatu to evaluate potential screening and treatment strategies to assist with control of cervical cancer. In a pilot study of 496 women, visual inspection and cytology were evaluated as screening tests for detection of CIN 2 or worse (CIN2+), observed in 21 of 206 subjects biopsied on the basis of abnormal visual inspection or cytology. Sensitivity of visual inspection with Lugol's Iodine for detection of CIN2+ on biopsy was 0.63, specificity was 0.32, and the positive predictive value was 0.09. For HSIL cytology, sensitivity was 0.99, specificity was 0.77, and the positive predictive value was 0.88. HSIL cytology was significantly more sensitive and had a significantly higher PPV for CIN 2+ than visual inspection (p<0.01). In a further study of 514 women, we compared testing for HR HPV and cytology as predictors of biopsy proven CIN 2+. Sensitivity of HSIL cytology for CIN2+ as established by loop excision of the cervix was 0.81, specificity was 0.94, and positive predictive value was 0.48. Sensitivity of a positive test for HR HPV for detection of CIN2+ was non-significantly different from cytology at 0.81, specificity was 0.94, and positive predictive value was 0.42. Combining the two tests gave a significantly lower sensitivity of 0.63, a specificity of 0.98, and a positive predictive value of 0.68. For women over 30 in a low resource setting without access to cytology, a single locally conduced test for high risk HPV with effective intervention could reduce cervical cancer risk as effectively as intervention based on cytology conducted in an accredited laboratory.
A number of medical journals have developed policies for accelerated publication of articles judged by the authors, the editors or the peer reviewers to be of special importance. However, the validity of these judgements is unknown. We therefore compared the importance of articles published on a “fast track” with those published in the usual way.
We identified 12 “case” articles — 6 articles from the New England Journal of Medicine that were prereleased on the journal's Web site before publication in print and 6 “fast-tracked” articles from The Lancet. We then identified 12 “control” articles matched to the case articles according to journal, disease or procedure of focus, theme area and year of publication. Forty-two general internists rated the articles, using 10-point scales, on dimensions addressing the articles' importance, ease of applicability and impact on health outcomes.
For each dimension, the mean score for the case articles was significantly higher than the mean score for the control articles: importance to clinical practice 7.6 v. 7.1 respectively (p = 0.001), importance from a public health perspective 6.5 v. 6.0 (p < 0.001), contribution to advancement of medical knowledge 6.2 v. 5.8 (p < 0.001), ease of applicability in practice 7.0 v. 6.5 (p < 0.001), potential impact on health outcomes 6.5 v. 5.9 (p < 0.001). Despite these general findings, in 5 of the 12 matched pairs of articles the control article had a higher mean score than the case article across all the dimensions.
The accelerated publication practices of 2 leading medical journals targeted articles that, on average, had slightly higher importance scores than similar articles published in the usual way. However, our finding of higher importance scores for control articles in 5 of the 12 matched pairs shows that current journal practices for selecting articles for expedited publication are inconsistent.