Effect of cold storage on platelet glycoprotein Ib and vesiculation

BACKGROUND: During storage of platelet concentrates at 22 degrees C, changes occur in surface glycoproteins, and membranous vesicles appear in the supernatant plasma. The extent of these changes during refrigerated storage is not known. STUDY DESIGN AND METHODS: Membranous microparticles and changes in surface or total glycoprotein Ib (GPIb) were studied in platelet concentrates divided into aliquots stored at either 4 degrees C or 22 degrees C for 5 days. RESULTS: The refrigerated platelets showed greater loss of total GPIb, slightly less binding of monoclonal antibodies to surface GPIb, and reduced aggregation response to ristocetin relative to the paired platelet controls at 22 degrees C. Moreover, the platelets stored at 4 degrees C produced 45-percent more microparticles and 64-percent more platelet factor 3 activity in the supernatant plasma than were produced by the controls. These differences were augmented by warming both 4 degrees C- and 22 degrees C-stored platelets at 37 degrees C for 1 to 4 hours. CONCLUSION: Storage of platelets at 4 degrees C causes increased membrane vesiculation and accelerated loss of GPIb. The magnitude of these differences was small, but it may contribute to marked reductions in platelet survival in circulation.     

Analysis of antibodies against components of the autonomic nervous system in diabetes mellitus

Antibodies to autonomic nervous system structures have previously been detected using a complement fixation immunofluorescence test in the sera of patients with insulin-dependent diabetes mellitus (IDDM) and non-insulin dependent diabetes mellitus (NIDDM). These antibodies might play a role in the aetiology of autonomic neuropathy. Sera from 45 IDDM, 40 NIDDM and 52 control subjects were tested by immunofluorescence for antibodies to human sympathetic ganglia, human adrenal medulla and rabbit vagus nerve. The use of human sympathetic ganglia was compared with rabbit tissue for the detection of sympathetic ganglia antibodies; the results for these autonomic nervous system antibodies were also compared with results using an ELISA. There was no relationship between the presence of antibodies detected by ELISA and those detected by immunofluorescence, but of 14 IDDM patients with thyroid antibodies, 12 had autonomic nervous system antibodies detected by either immunofluorescence or ELISA (p < 0.005 compared to patients without thyroid antibodies). To further characterize the autoantigen(s), immunoblotting was performed. An adrenal antigen corresponding to 74 kDa was detected in sera from three patients, only one of whom had antibodies detectable by ELISA and immunofluorescence. One IDDM serum showed specific binding to a vagus nerve antigen corresponding to 33 kDa. No specific binding to sympathetic ganglia antigen was demonstrated. Antibodies against autonomic nervous system antigens are an inconsistent feature of diabetes, and appear more associated with coincidental autoimmunity against other organs such as the thyroid.      

Assessing diagnosis in heart failure: which features are any use?

We assessed the value of symptoms, past history, medications and signs in the evaluation of patients who might have heart failure secondary to left ventricular systolic dysfunction. An open-access echocardiography service was set up to help identify patients with left ventricular systolic dysfunction who might benefit from treatment with an angiotensin-converting-enzyme inhibitor. History and examination were recorded for each of these patients. The patients were divided into groups according to whether left ventricular systolic function was preserved or not and whether various clinical features were present or not. Of 259 consecutive patients studied, 41 had impairment of left ventricular systolic function as assessed by echocardiography. Past history of myocardial infarction and displaced apex beat were the best single predictors of left ventricular systolic dysfunction as assessed by echocardiography. The combination of past history of myocardial infarction and displaced apex had the best positive predictive value of all. Patients with such clinical features or combinations of clinical features may not need echocardiography, and where access to this resource is limited, it could be reserved for patients without such diagnostic features.      

Polyclonal antibodies against the NB1-bearing 58- to 64-kDa glycoprotein of human neutrophils do not identify an NB2-bearing molecule

The neutrophil-specific NB antigen system has been serologically characterized with human alloantisera. Two alleles, NB1 and NB2, have been described; however, there may be important quantitative or qualitative variation in the expression of NB1 and NB2. Human alloantibodies have been used to identify the 58- to 64-kDa glycoprotein (GP) on which NB1 antigen is located, but an NB2 antigen- bearing molecule has not yet been identified. To identify the NB2 molecule, human alloantibody to NB1 was used to isolate the 58- to 64- kDa NB1 GP, and rabbits were immunized with this GP. Two rabbit antisera were produced. Both antisera immunoblotted and immunoprecipitated the 58- to 64-kDa GP on which NB1 is located, but neither identified the molecule on which NB2 is located. The inability of two rabbit polyclonal antibodies specific for the NB1 molecule to react with the NB2-bearing molecule suggests that considerable differences may exist between these two molecules or that NB2 as currently defined is not related to NB1.     

Broad-spectrum respiratory tract pathogen identification using resequencing DNA microarrays

The exponential growth of pathogen nucleic acid sequences available in public domain databases has invited their direct use in pathogen detection, identification, and surveillance strategies. DNA microarray technology has offered the potential for the direct DNA sequence analysis of a broad spectrum of pathogens of interest. However, to achieve the practical attainment of this potential, numerous technical issues, especially nucleic acid amplification, probe specificity, and interpretation strategies of sequence detection, need to be addressed. In this report, we demonstrate an approach that combines the use of a custom-designed Affymetrix resequencing Respiratory Pathogen Microarray (RPM v.1) with methods for microbial nucleic acid enrichment, random nucleic acid amplification, and automated sequence similarity searching for broad-spectrum respiratory pathogen surveillance. Successful proof-of-concept experiments, utilizing clinical samples obtained from patients presenting adenovirus or influenza virus-induced febrile respiratory illness (FRI), demonstrate the ability of this approach for correct species- and strain-level identification with unambiguous statistical interpretation at clinically relevant sensitivity levels. Our results underscore the feasibility of using this approach to expedite the early surveillance of diseases, and provide new information on the incidence of multiple pathogens.     

Autoimmunity as an aetiological factor in vitiligo

Vitiligo is a common dermatological disorder characterized by the presence on the skin of depigmented macules resulting from the destruction of cutaneous melanocytes. Autoimmunity is an important hypothesis with regard to vitiligo aetiology and the evidence for autoimmune responses being involved in the pathogenesis of this disorder will be discussed in the present review. All immune system compartments, including innate and adaptive immunity have been implicated in vitiligo development. Particularly relevant are autoantibodies and autoreactive T cells in vitiligo patients that have cytotoxic effects upon pigment cells. Furthermore, predisposition to vitiligo appears to be associated with certain alleles of the major histocompatibility complex class II antigens as well as with other autoimmune-susceptibility genes. Moreover, the association of vitiligo with autoimmune disorders, the animal models of the disease, and the positive response to immunosuppressive therapeutic agents emphasize the role of autoimmunity in the development of this disorder.     

Endoscopic retrograde cholangiopancreatography in the treatment of intraoperatively demonstrated choledocholithiasis

INTRODUCTION

The aim of this study was to determine the efficacy and complications of postoperative endoscopic retrograde cholangiopancreatography (ERCP) in confirming and treating choledocholithiasis found at intraoperative cholangiography during laparoscopic cholecystectomy.

METHODS

Patients who had undergone ERCP following a cholecystectomy between 2008 and 2011 with an indication of intraoperative cholangiography findings consistent with choledocholithiasis were identified from a prospectively collected database of a single endoscopist. Deep biliary access rate, confirmation of choledocholithiasis, clearance rate of bile duct stones, delay between cholecystectomy and postoperative ERCP, and the complication rates following the procedure were analysed.

RESULTS

The median age of the 41 patients (16 male, 25 female) was 42 years (range: 18–82 years). Sixteen surgeons performed the operations with a median delay of 6 days (range: 1–103 days) between cholecystectomy and postoperative ERCP. Common bile duct access was achieved in 100% of the patients, with ERCP taking a median time of 16 minutes (range: 6–40 minutes). Initial ERCP confirmed the presence of a stone in 30 patients (73%) and successful stone removal occurred in 28 of these 30 patients (93%) during the first ERCP and in the remaining 2 on a subsequent ERCP. Following ERCP, two patients (4.9%) experienced extended hospital stays for four and eight days owing to complications, including one patient (2.4%) with mild acute pancreatitis.

CONCLUSIONS

This study demonstrates that postoperative ERCP is highly effective in both confirming and treating choledocholithiasis. However, there is a significant risk of short-term complications that must be taken into consideration when deciding management.