ABO compatibility can influence the results of platelet transfusion. Results of a randomized trial

Sixty consecutive patients with untreated acute leukemia alternately received either ABO-matched or ABO-mismatched random-donor platelet transfusions prepared from pooled platelet concentrate stored for 1 to 3 days. Patients were assigned randomly to receive matched or mismatched platelets as their first transfusion, and the first four transfusions were analyzed. In 40 evaluable patients, there was no significant difference (paired t test) between the 10-minute posttransfusion corrected count increments (CCI) of the initial transfusions of matched and mismatched platelets. In contrast, the second matched transfusion was significantly better than the second mismatched transfusion. This effect of ABO compatibility was particularly pronounced in a subset of patients. Six patients in whom mismatched transfusions were consistently inferior to matched transfusions had either a significant increase in anti-A or -B isoagglutinin titers following the first transfusion or elevated titers before or at the conclusion of the study. Conversely, in five patients in whom there was no apparent effect of ABO mismatching, only one had an increase in isoagglutinin titer. Platelet survival was not altered as the ratio of 18-hour to 10-minute posttransfusion CCl was 0.6 for both matched and mismatched platelet transfusions. These data demonstrate that ABO compatibility can affect the results of random-donor platelet transfusions and that patients who experience poor increments from ABO-mismatched platelets may benefit from a trial of ABO-compatible platelets before the initiation of HLA-matched platelet transfusion.     

PRIMARY MENINGOCOCCAL CONJUNCTIVITIS IN CHILDREN

SUMMARY Four cases of primary meningococcal conjunctivitis in children are reported. This represents an incidence of 2% of patients presenting with conjunctivitis to a paediatric A&E department. All were initially treated with topical chloramphenicol, followed by systemic rifampicin once the diagnosis had been established. No ocular or systemic complications developed, nor recolonisation of the conjunctiva or colonisation of the nasopharynx at follow-up (1–2 years).     

Total radical trapping antioxidant potential (TRAP) and exercise

The relationship between physical activity, physical fitness and total radical trapping antioxidant potential (TRAP) was examined in the Northern Ireland Health and Activity Survey. This was a cross-sectional population study (n = 1600) using a two-stage probability sample of the population. TRAP was calculated using the sum of the individual serum antioxidant concentrations (urate, protein thiols, ascorbate, alpha tocopherol and bilirubin) multiplied by their respective stoichiometric values. Physical fitness was determined by estimation of VO2max by extrapolation from submaximal oxygen uptake, and physical activity was recorded by computer-assisted interview. Mean serum TRAP concentrations were significantly higher in males (653 +/- 8.2 mumol/l, mean +/- SEM) compared to females (564 +/- 8.0 mumol/l) (p < 0.0001). Both male and female smokers had significantly lower TRAP values than non-smokers (males p < 0.0001, females p = 0.02). In females, there was a positive relationship of TRAP with age (p < 0.001) and body mass index (p < 0.001) but a negative relationship with physical fitness (p < 0.05). The known beneficial effects of exercise and activity do not appear to be directly mediated through increased antioxidant status.      

A study of confidential unit exclusion

The effectiveness of the confidential unit exclusion (CUE) procedure recommended by the Food and Drug Administration has been questioned by the blood banking community. The purpose of this study was to determine whether donors were informing the blood center correctly regarding the disposition (transfuse or do not transfuse) of their donated blood. A letter explaining the confidential study and requesting permission to send the participant a questionnaire noting his or her self-exclusion choice was mailed to 230 donors who had chosen transfuse and 276 donors who had chosen do not transfuse. After consent was obtained, participants were sent a second packet and asked to indicate whether they had chosen correctly and, if not, to identify reasons for that incorrect choice. A seven-word terminology quiz made up of words from the CUE form was also enclosed. All participants who had chosen transfuse indicated that this was the correct choice. Approximately 50 percent of those who had chosen do not transfuse indicated that this was an incorrect choice; the most common reason was that "I was not paying attention." The most frequently misunderstood term was "confidential." Donors who chose do not transfuse had a significantly higher rate of error on the terminology quiz (p less than 0.01) than did those who chose transfuse.     

Adaptive differentiation of murine lymphocytes. IV. (Responder × Nonresponder) F(1) T cells can be taught to preferentially help nonresponder,rather than responder, B cells

Responses to the synthetic terpolymer L-glutamic acid, L-lysine, L-tyrosine (GLT) in the mouse are controlled by H-2-1inked Ir-GLTgenes. (Responder × nonresponder) F(1) hybrid mice, themselves phenotypic responders, can be primed with GLT to develop specific helper cells capable of interacting with 2,4-dinitrophenyl hapten (DNP)-primed F(1) B cells in response to DNP-GLT. Unlike the indiscriminant ability of F(1) helper T cells for conventional antigens (i.e. not Ir gene-controlled), which can help B cells of either parental type (as well as F(1)) equally well, GLT-primed F(1) T cells can only provide help under normal circumstances for B lymphocytes of responder parent origin; they are unable to communicate effectively with nonresponder parental B cells (1, and the present studies). The present studies reveal, however, that the induction of a parental cell-induced allogeneic effect during priming of F(1) mice to GLT actually dictates the direction of cooperating preference that will be displayed by such F(1) helper cells for B cells of one parental type or the other. Thus, F(1) T cells, primed to GLT under the influence of an allogeneic effect induced by parental BALB/c cells, develop into effective helpers for nonresponder A/J B cells, but fail to develop effective helpers for responder BALB/c B cells, and vice-versa. In contrast, F(1) T cells, primed to GLT under the influence of an allogeneic effect induced by either parental type, display significantly enhanced levels of helper activity for B cells derived from F(1) donors. These results are interpreted to reflect the existence of two interdependent events provoked by the allogeneic effect: one event augments the differentiation of GLT-specific helper T cells belonging to the subset corresponding to the opposite parental type; this would explain the development of increased helper activity provided to partner B cells of opposite parental type (as well as of F(1) origin). The second event, we postulate, involves the production of responses against the receptors which normally self-recognize native cell interaction determinants; this form of anti-idiotype response is restricted against self- recognizing receptors of the same parental type used for induction of the allogeneic effect, hence explaining diminished helper activity of such F(1) cells for partner B lymphocytes of corresponding parental type.     

Non-Muscle Myosin IIA Differentially Regulates Intestinal Epithelial Cell Restitution and Matrix Invasion

Epithelial cell motility is critical for self-rejuvenation of normal intestinal mucosa, wound repair, and cancer metastasis. This process is regulated by the reorganization of the F-actin cytoskeleton, which is driven by a myosin II motor. However, the role of myosin II in regulating epithelial cell migration remains poorly understood. This study addressed the role of non-muscle myosin (NM) IIA in two different modes of epithelial cell migration: two-dimensional (2-D) migration that occurs during wound closure and three-dimensional (3-D) migration through a Matrigel matrix that occurs during cancer metastasis. Pharmacological inhibition or siRNA-mediated knockdown of NM IIA in SK-CO15 human colonic epithelial cells resulted in decreased 2-D migration and increased 3-D invasion. The attenuated 2-D migration was associated with increased cell adhesiveness to collagen and laminin and enhanced expression of β1-integrin and paxillin. On the 2-D surface, NM IIA-deficient SK-CO15 cells failed to assemble focal adhesions and F-actin stress fibers. In contrast, the enhanced invasion of NM IIA-depleted cells was dependent on Raf-ERK1/2 signaling pathway activation, enhanced calpain activity, and increased calpain-2 expression. Our findings suggest that NM IIA promotes 2-D epithelial cell migration but antagonizes 3-D invasion. These observations indicate multiple functions for NM IIA, which, along with the regulation of the F-actin cytoskeleton and cell-matrix adhesions, involve previously unrecognized control of intracellular signaling and protein expression.In the human intestine, a single layer of polarized epithelial cells creates a protective barrier that separates the body interior from the intestinal lumen. This barrier is capable of withstanding a variety of mechanical, chemical, and biological stressors and represents a dynamic self-renewing entity. The dynamic nature of the normal intestinal epithelium is illustrated by the fact that this epithelial sheet is constantly moving at a speed of 5 to 10 μm/h.¹ This movement plays a vital role in the normal life cycle of intestinal epithelial cells. Indeed, epitheliocytes that originate from stem cells at the bottom of intestinal crypts differentiate and migrate along the crypt-surface axis and eventually shed from the intestinal surface.² In addition to its role in normal intestinal homeostasis, epithelial cell migration significantly contributes to the pathophysiology of intestinal disorders such as inflammatory bowel disease and colorectal cancer. In the former disease, a collective movement of the epithelial sheet plays a major role in closure of mucosal wounds, which is known as epithelial restitution.^3,4 In the latter pathology, invasion of epithelial cancer cells into underlying tissues results in tumor dissemination.^5,6 Thus, epithelial cell motility is a fundamental feature of normal intestinal mucosal physiology, mucosal repair, and cancer metastasis.Cell migration is generally considered as a cyclic process initiated by extension of protrusions in the direction of migration and completed by the retraction of the trailing end of the cell.^7,8 Reorganization of actin filaments drives the entire migration cycle by generating forces to extend membrane protrusions and to move the cell body forward. This reorganization of filamentous (F)-actin is mediated by two major mechanisms: the so-called F-actin “treadmilling” that involves actin polymerization and depolymerization at opposite filament ends, and contraction of filaments driven by the myosin II motor.^7,8,9 Whereas F-actin treadmilling is known to mediate protrusions at the migrating cell front, the roles of myosin II in cell motility appear to be more diverse and involve regulation of protrusion dynamics, cell-matrix adhesions, and forward translocation of the cell body.^7,8,9,10 Therefore, myosin II-driven contractility can be considered as a key mechanism integrating different steps of cell migration.Myosin II is a motor protein that utilizes ATP to move actin filaments. This motor functions as a heterohexamer composed of two heavy chains and two pairs of light chains.^11,12 The heavy chain consists of a globular head that binds to actin and hydrolyzes ATP and an extended tail that coils together with another heavy chain tail to form a rigid rod-like structure. The tails of multiple myosin II molecules readily self-associate, creating bipolar myosin aggregates that are crucial for actin filament movement and bundling.^11,12 Epithelial cells express non-muscle myosin (NM) II, which is characterized by three different heavy chain isoforms: IIA, IIB, and IIC.^13,14 These isoforms possess a high degree (64% to 80%) of sequence similarity, but have different enzymatic/biochemical properties.^15,16 As a result, different NM II heavy chains may have either unique^{15,17,18,19,20} or interchangeable roles^21,22 in regulating cell shape, cell adhesion, cytokinesis, and vesicular traffic.Several recent studies have yielded conflicting data on the involvement of NM II in epithelial cell migration. Thus, pharmacological inhibition of NM II with blebbistatin was shown to attenuate migration of pancreatic and renal epithelial cells,^23,24 but reportedly did not affect motility of mammary and prostate epithelial cells.²⁵ In other studies, small interfering (si)RNA-mediated knockdown of the NM II heavy chain A isoform (hereafter referred to as NM IIA) was found to suppress migration of mammary epithelial cells²⁶ but enhanced the motility of lung epithelial cells.¹⁹ These contradictory data may reflect peculiar behavior of different cell lines, as well as different experimental conditions used to study cell migration.^24,27 Despite its biological importance, the role of NM II in migration of intestinal epithelial cells has not yet been studied.The present study was designed to investigate the role of NM IIA in intestinal epithelial cell migration. This myosin II isoform was shown to be a major generator of traction forces in motile cells¹⁷ and it is abundantly expressed in both well-differentiated epithelial cells¹⁵ and their embryonic precursors.²⁸ The role of NM IIA was examined by using two different models of cell migration: a two-dimensional (2-D or planar) wound closure assay and a three-dimensional (3-D) Matrigel invasion assay, resembling restitution of injured epithelial sheets, and metastatic dissemination of colorectal tumors, respectively. We report that inhibition of NM IIA oppositely affects epithelial cell restitution and invasion via multiple mechanisms that involve alterations in cell-matrix adhesion and F-actin organization, as well as profound changes in intracellular signaling and protein expression.     

在白色念珠菌URM3622中生产胶原酶

采用三种设计方案考察了白色念珠菌URM3622胞外分泌生产胶原酶的培养条件。首先进行26—2部分因子试验,结果表明转速和底物浓度对胶原酶的产量影响显著。根据以上结果,又设计了两次连续的23全因子分析,结果表明,在pH7．0、转速160r／min、底物浓度2％条件下培养白色念珠菌,发酵所得胶原酶活性最高。在pH8．2、45℃的环境中,胶原酶活性最大。所获胶原酶在pH7．2～8．2及28～45℃范围内稳定。     

JAM-related proteins in mucosal homeostasis and inflammation

Mucosal surfaces are lined by epithelial cells that form a physical barrier protecting the body against external noxious substances and pathogens. At a molecular level, the mucosal barrier is regulated by tight junctions (TJs) that seal the paracellular space between adjacent epithelial cells. Transmembrane proteins within TJs include junctional adhesion molecules (JAMs) that belong to the cortical thymocyte marker for Xenopus family of proteins. JAM family encompasses three classical members (JAM-A, JAM-B, and JAM-C) and related molecules including JAM4, JAM-like protein, Coxsackie and adenovirus receptor (CAR), CAR-like membrane protein and endothelial cell-selective adhesion molecule. JAMs have multiple functions that include regulation of endothelial and epithelial paracellular permeability, leukocyte recruitment during inflammation, angiogenesis, cell migration, and proliferation. In this review, we summarize the current knowledge regarding the roles of the JAM family members in the regulation of mucosal homeostasis and leukocyte trafficking with a particular emphasis on barrier function and its perturbation during pathological inflammation.