PMCC PMCC

Search tips
Search criteria

Advanced
Results 1-6 (6)
 

Clipboard (0)
None

Select a Filter Below

Journals
Year of Publication
Document Types
1.  The Tumor Targeted Superantigen ABR-217620 Selectively Engages TRBV7-9 and Exploits TCR-pMHC Affinity Mimicry in Mediating T Cell Cytotoxicity 
PLoS ONE  2013;8(10):e79082.
The T lymphocytes are the most important effector cells in immunotherapy of cancer. The conceptual objective for developing the tumor targeted superantigen (TTS) ABR-217620 (naptumomab estafenatox, 5T4Fab-SEA/E-120), now in phase 3 studies for advanced renal cell cancer, was to selectively coat tumor cells with cytotoxic T lymphocytes (CTL) target structures functionally similar to natural CTL pMHC target molecules. Here we present data showing that the molecular basis for the anti-tumor activity by ABR-217620 resides in the distinct interaction between the T cell receptor β variable (TRBV) 7-9 and the engineered superantigen (Sag) SEA/E-120 in the fusion protein bound to the 5T4 antigen on tumor cells. Multimeric but not monomeric ABR-217620 selectively stains TRBV7-9 expressing T lymphocytes from human peripheral blood similar to antigen specific staining of T cells with pMHC tetramers. SEA/E-120 selectively activates TRBV7-9 expressing T lymphocytes resulting in expansion of the subset. ABR-217620 selectively triggers TRBV7-9 expressing cytotoxic T lymphocytes to kill 5T4 positive tumor cells. Furthermore, ABR-217620 activates TRBV7-9 expressing T cell line cells in the presence of cell- and bead-bound 5T4 tumor antigen. Surface plasmon resonance analysis revealed that ABR-217620 binds to 5T4 with high affinity, to TRBV7-9 with low affinity and to MHC class II with very low affinity. The T lymphocyte engagement by ABR-217620 is constituted by displaying high affinity binding to the tumor cells (KD approximately 1 nM) and with the mimicry of natural productive immune TCR-pMHC contact using affinities of around 1 µM. This difference in kinetics between the two components of the ABR-217620 fusion protein will bias the binding towards the 5T4 target antigen, efficiently activating T-cells via SEA/E-120 only when presented by the tumor cells.
doi:10.1371/journal.pone.0079082
PMCID: PMC3806850  PMID: 24194959
2.  Both Acute and Chronic Placental Inflammation Are Overrepresented in Term Stillbirths: A Case-Control Study 
Objective. To elucidate differences in the frequency and severity of acute chorioamnionitis (CAM) and chronic villitis in placentas from stillborns compared with liveborns at term and to evaluate other risk factors and placental findings. Design. Case-control study. Setting. All delivery wards in major Stockholm area. Population or Sample. Placentas from stillborn/case (n = 126) and liveborn/control (n = 273) neonates were prospectively collected between 2002 and 2005. Methods. CAM was assessed on a three-grade scale based on the presence and distribution of polymorphonuclear leucocytes in the chorion/amnion. The presence of vasculitis and funisitis was recorded separately. Chronic villitis was diagnosed by the presence of mononuclear cells in the villous stroma. Relevant clinical data were collected from a specially constructed, web-based database. The statistic analyses were performed using multivariable logistic regression. Results. CAM (especially severe, AOR: 7.39 CI: 3.05–17.95), villous immaturity (AOR: 7.17 CI: 2.66–19.33), villitis (<1 % AOR: 4.31 CI: 1.16–15.98; ≥1 %, AOR: 3.87 CI: 1.38–10.83), SGA (AOR: 7.52 CI: 3.06–18.48), and BMI >24.9 (AOR: 2.06 CI: 1.21–3.51) were all connected to an elevated risk of term stillbirth. Conclusions. We found that CAM, chronic villitis, villous immaturity, SGA, and maternal overweight, but not vasculitis or funisitis are independently associated with risk for stillbirth at term.
doi:10.1155/2012/293867
PMCID: PMC3433132  PMID: 22966214
3.  Study circles improve the precision in nutritional care in special accommodations 
Food & Nutrition Research  2009;53:10.3402/fnr.v53i0.1950.
Background
Disease-related malnutrition is a major health problem in the elderly population, but it has until recently received very little attention, especially are management issues under-explored. By identifying residents at the risk of undernutrition (UN), appropriate nutritional care can be provided.
Objective
To investigate if study circles and policy documents improve the precision in nutritional care and decrease the prevalence of low or high body mass index (BMI).
Design
Pre and post-intervention study.
Setting
Special accommodations (nursing homes) within six municipalities were involved.
Participants
In 2005, 1,726 (90.4%) of 1,910 residents agreed to participate and in 2007, 1,526 (81.8%) of 1,866 residents participated.
Intervention
Study circles in one municipality, having a policy document in one municipality and no intervention in four municipalities.
Measurements
Risk of UN was defined as involving any of: involuntary weight loss; low BMI; and/or eating difficulties. Overweight was defined as high BMI.
Results
In 2005 and 2007, 64% and 66% of residents, respectively, were at the risk of UN. In 2007, significantly more patients in the study circle municipality were accurately provided protein and energy enriched food (PE-food) compared to the no intervention municipalities. There was a decrease between 2005 and 2007 in the prevalence of low BMI in the study circle municipality, but the prevalence of overweight increased in the policy document municipality.
Conclusions
Study circles improve the provision of PE-food for residents at the risk of UN and can possibly decrease the prevalence of low BMI. It is likely that a combination of study circles and implementation of a policy document focusing on screening and on actions to take if the resident is at UN risk can give even better results.
doi:10.3402/fnr.v53i0.1950
PMCID: PMC2754113  PMID: 19798421
education; malnutrition; undernutrition; overweight; special accommodation; quality improvement
4.  An evaluation of classification systems for stillbirth 
Background
Audit and classification of stillbirths is an essential part of clinical practice and a crucial step towards stillbirth prevention. Due to the limitations of the ICD system and lack of an international approach to an acceptable solution, numerous disparate classification systems have emerged. We assessed the performance of six contemporary systems to inform the development of an internationally accepted approach.
Methods
We evaluated the following systems: Amended Aberdeen, Extended Wigglesworth; PSANZ-PDC, ReCoDe, Tulip and CODAC. Nine teams from 7 countries applied the classification systems to cohorts of stillbirths from their regions using 857 stillbirth cases. The main outcome measures were: the ability to retain the important information about the death using the InfoKeep rating; the ease of use according to the Ease rating (both measures used a five-point scale with a score <2 considered unsatisfactory); inter-observer agreement and the proportion of unexplained stillbirths. A randomly selected subset of 100 stillbirths was used to assess inter-observer agreement.
Results
InfoKeep scores were significantly different across the classifications (p ≤ 0.01) due to low scores for Wigglesworth and Aberdeen. CODAC received the highest mean (SD) score of 3.40 (0.73) followed by PSANZ-PDC, ReCoDe and Tulip [2.77 (1.00), 2.36 (1.21), 1.92 (1.24) respectively]. Wigglesworth and Aberdeen resulted in a high proportion of unexplained stillbirths and CODAC and Tulip the lowest. While Ease scores were different (p ≤ 0.01), all systems received satisfactory scores; CODAC received the highest score. Aberdeen and Wigglesworth showed poor agreement with kappas of 0.35 and 0.25 respectively. Tulip performed best with a kappa of 0.74. The remainder had good to fair agreement.
Conclusion
The Extended Wigglesworth and Amended Aberdeen systems cannot be recommended for classification of stillbirths. Overall, CODAC performed best with PSANZ-PDC and ReCoDe performing well. Tulip was shown to have the best agreement and a low proportion of unexplained stillbirths. The virtues of these systems need to be considered in the development of an international solution to classification of stillbirths. Further studies are required on the performance of classification systems in the context of developing countries. Suboptimal agreement highlights the importance of instituting measures to ensure consistency for any classification system.
doi:10.1186/1471-2393-9-24
PMCID: PMC2706223  PMID: 19538759
5.  Crystal Structure of a Yeast Aquaporin at 1.15 Å Reveals a Novel Gating Mechanism 
PLoS Biology  2009;7(6):e1000130.
Atomic-resolution X-ray crystallography, functional analyses, and molecular dynamics simulations suggest a novel mechanism for the regulation of water flux through the yeast Aqy1 water channel.
Aquaporins are transmembrane proteins that facilitate the flow of water through cellular membranes. An unusual characteristic of yeast aquaporins is that they frequently contain an extended N terminus of unknown function. Here we present the X-ray structure of the yeast aquaporin Aqy1 from Pichia pastoris at 1.15 Å resolution. Our crystal structure reveals that the water channel is closed by the N terminus, which arranges as a tightly wound helical bundle, with Tyr31 forming H-bond interactions to a water molecule within the pore and thereby occluding the channel entrance. Nevertheless, functional assays show that Aqy1 has appreciable water transport activity that aids survival during rapid freezing of P. pastoris. These findings establish that Aqy1 is a gated water channel. Mutational studies in combination with molecular dynamics simulations imply that gating may be regulated by a combination of phosphorylation and mechanosensitivity.
Author Summary
All living organisms must regulate precisely the flow of water into and out of cells in order to maintain cell shape and integrity. Proteins of one family, the aquaporins, are found in virtually every living organism and play a major role in maintaining water homeostasis by acting as regulated water channels. Here we describe the first crystal structure of a yeast aquaporin, Aqy1, at 1.15 Å resolution, which represents the highest resolution structural data obtained to date for a membrane protein. Using this structural information, we address an outstanding biological question surrounding yeast aquaporins: what is the functional role of the amino-terminal extension that is characteristic of yeast aquaporins? Our structural data show that the amino terminus of Aqy1 fulfills a novel gate-like function by folding to form a cytoplasmic helical bundle with a tyrosine residue entering the water channel and occluding the cytoplasmic entrance. Molecular dynamics simulations and functional studies in combination with site-directed mutagenesis suggest that water flow is regulated through a combination of mechanosensitive gating and post-translational modifications such as phosphorylation. Our study therefore provides insight into a unique mechanism for the regulation of water flux in yeast.
doi:10.1371/journal.pbio.1000130
PMCID: PMC2688079  PMID: 19529756
6.  Causes of death and associated conditions (Codac) – a utilitarian approach to the classification of perinatal deaths 
A carefully classified dataset of perinatal mortality will retain the most significant information on the causes of death. Such information is needed for health care policy development, surveillance and international comparisons, clinical services and research. For comparability purposes, we propose a classification system that could serve all these needs, and be applicable in both developing and developed countries. It is developed to adhere to basic concepts of underlying cause in the International Classification of Diseases (ICD), although gaps in ICD prevent classification of perinatal deaths solely on existing ICD codes.
We tested the Causes of Death and Associated Conditions (Codac) classification for perinatal deaths in seven populations, including two developing country settings. We identified areas of potential improvements in the ability to retain existing information, ease of use and inter-rater agreement. After revisions to address these issues we propose Version II of Codac with detailed coding instructions.
The ten main categories of Codac consist of three key contributors to global perinatal mortality (intrapartum events, infections and congenital anomalies), two crucial aspects of perinatal mortality (unknown causes of death and termination of pregnancy), a clear distinction of conditions relevant only to the neonatal period and the remaining conditions are arranged in the four anatomical compartments (fetal, cord, placental and maternal).
For more detail there are 94 subcategories, further specified in 577 categories in the full version. Codac is designed to accommodate both the main cause of death as well as two associated conditions. We suggest reporting not only the main cause of death, but also the associated relevant conditions so that scenarios of combined conditions and events are captured.
The appropriately applied Codac system promises to better manage information on causes of perinatal deaths, the conditions associated with them, and the most common clinical scenarios for future study and comparisons.
doi:10.1186/1471-2393-9-22
PMCID: PMC2706222  PMID: 19515228

Results 1-6 (6)