A New Framework for Interpreting the Outcomes of Imperfectly Blinded Controlled Clinical Trials

It is well known that the outcome of an intervention is affected both by the inherent effects of the intervention and the patient''s expectations. For this reason in comparative clinical trials an effort is made to conceal the nature of the administered intervention from the participants in the trial i.e. to blind the trial. Yet, in practice perfect blinding is impossible to ensure or even verify post hoc. The current clinical standard is to follow up the trial with an auxiliary questionnaire, which allows trial participants to express in closed form their belief concerning the intervention, i.e. trial group assignment (treatment or control). Auxiliary questionnaire responses are then used to compute the extent of blinding in the trial in the form of a blinding index. If the estimated extent of blinding exceeds a particular threshold the trial is deemed sufficiently blinded; otherwise, the strength of evidence of the trial is brought into question. This may necessitate that the trial is repeated. In this paper we make several contributions. Firstly, we identify a series of problems of the aforesaid clinical practice and discuss them in context of the most commonly used blinding indexes. Secondly, we formulate a novel approach for handling imperfectly blinded trials. We adopt a feedback questionnaire of the same form as that which is currently in use, but interpret the collected data using a novel statistical method, significantly different from that proposed in the previous work. Unlike the previously proposed approaches, our method is void of any ad hoc free parameters and robust to small changes in the participants'' feedback responses. Our method also does not discard any data and is not predicated on any strong assumptions used to interpret participants'' feedback. The key idea behind the present method is that it is meaningful to compare only the corresponding treatment and control participant sub-groups, that is, sub-groups matched by their auxiliary responses. A series of experiments on simulated trials is used to demonstrate the effectiveness of the proposed approach and its superiority over those currently in use.     

Mechanical Signaling on the Single Protein Level Studied Using Steered Molecular Dynamics

Efficient communication between the cell and its external environment is of the utmost importance to the function of multicellular organisms. While signaling events can be generally characterized as information exchange by means of controlled energy conversion, research efforts have hitherto mainly been concerned with mechanisms involving chemical and electrical energy transfer. Here, we review recent computational efforts addressing the function of mechanical force in signal transduction. Specifically, we focus on the role of steered molecular dynamics (SMD) simulations in providing details at the atomic level on a group of protein domains, which play a fundamental role in signal exchange by responding properly to mechanical strain. We start by giving a brief introduction to the SMD technique and general properties of mechanically stable protein folds, followed by specific examples illustrating three general regimes of signal transfer utilizing mechanical energy: purely mechanical, mechanical to chemical, and chemical to mechanical. Whenever possible the physiological importance of the example at hand is stressed to highlight the diversity of the processes in which mechanical signaling plays a key role. We also provide an overview of future challenges and perspectives for this rapidly developing field.     

Patients' satisfaction with prosthetic devices

The purpose of the paper was to ascertain the factors which affect the satisfaction of patients with the prosthetic therapy. The purpose of the paper was also to ascertain if there are common factors characteristic for patients dissatisfied with the prosthetic therapy although the specialist appraises it as objectively successful. 52 patients of the Clinical Institute for Rehabilitation and Orthopedic Devices were participating in the research, to which, after unsuccessful surgical-prosthetic rehabilitation, reamputation and prosthetic provision was carried out, which was appraised successful by the doctor. It was endeavored to appraise to what extent the appraisal by the doctor corresponds to patient's satisfaction. On the basis of the questionnaire elaborated specifically for this research and the statistical processing, it was concluded that where the doctor appraised the prosthetic therapy as successful, the same opinion was shared by the majority of the patients (92.3%). Patients are similarly satisfied with the function and the esthetic quality of the prosthesis (73%). The reason why 7.7% of patients are dissatisfied in cases when the doctor considers that there are no objective reasons for that should be sought in non-medical factors. The age, the education, the marital status, the income state, the size of the residence and the regional affiliation do not have a significant influence on the satisfaction of patients with the prosthesis (p > 0.05). Patients with a minor handicap achieve satisfaction with the prosthetic therapy faster, as well as the right-handed persons if the prosthesis on the right-hand extremity is in question (p < 0.05). This investigation showed that the responsibility of not wearing prosthetic aids, both orthopedic, and dental prostheses, couldn't be only neuroticism by prosthetic patients, because that connection is not statistically significant (p < 0.09).     

Denture repairs in different regions of Croatia in relation to prosthodontic teams

The purpose of this paper is to evaluate the incidence of denture repairs in different districts of Croatia through the year of 2002. and to analyse the percentage of different repairs (relinings, simple repairs up to 2 elements and complicated repairs-more than 2 elements) in relation to prosthodontic teams. Data on the number of dentures, and the number and types of denture repairs delivered in the Croatian regions of Zagreb, Rijeka, Split and Karlovac were obtained from the Croatian Institute for Health Insurance for the whole of the year 2002. Information of the number of prosthodontic teams operating in those regions was also obtained. Proportionally more denture repairs were carried out in Karlovac (18%) than Split (5%). The smallest percantage of dentures that required relining was registered in Split and the highest in Rijeka (chi2 = 36.7, p < 0.01). The smallest percentage of simple repairs was registered in Rijeka and the highest in Split (chi2 = 24.3, p < 0.01). The smallest percentage of complicated repairs was registered in Split and the highest in Karlovac. In each region the proportion of denture repairs and types of repairs were correlated with a number of prosthodontic teams in that region. Karlovac had the smallest percentage of specialistic prosthodontic teams and the highest rate of denture repairs.     

Metabolic adaptation of endothelial cells to substrate deprivation

Endothelial cells are known to be metabolicallyrather robust. To study the mechanisms involved, porcine aorticendothelial cells (PAEC), cultured on microcarrier beads, were perfusedwith glucose (10 mM) or with substrate-free medium. Substrate-free perfusion for 2 h induced an almost complete loss of nucleoside triphosphates (³¹P-NMR) anddecreased heat flux, a measure of total energy turnover, by >90% inparallel microcalorimetric measurements. Heat flux and nucleosidetriphosphates recovered after addition of glucose. Because proteinsynthesis is a major energy consumer in PAEC, the rate of proteinsynthesis was measured([¹⁴C]leucineincorporation). Reduction or blockade of energy supply resulted in apronounced reduction in the rate of protein synthesis (up to 80%reduction). Intracellular triglyceride stores were decreased by ~60%after 2 h of substrate-free perfusion. Under basal perfusionconditions, PAEC released ~30 pmol purine · mg protein¹ · min¹,i.e., 16% of the cellular ATP per hour, while ATP remained constant. Substrate deprivation increased the release of various purines andpyrimidines about threefold and also induced a twofold rise in purinede novo synthesis([¹⁴C]formate). Theseresults demonstrate that PAEC are capable of recovering from extendedperiods of substrate deprivation. They can do so by a massivedownregulation of their energy expenditure, particularly proteinsynthesis, while at the same time using endogenous triglycerides assubstrates and upregulating purine de novo synthesis to compensate forthe loss of purines.     

Delivery of a Chlamydial Adhesin N-PmpC Subunit Vaccine to the Ocular Mucosa Using Particulate Carriers

Trachoma, caused by the intracellular bacterium Chlamydia trachomatis (Ct), remains the world’s leading preventable infectious cause of blindness. Recent attempts to develop effective vaccines rely on modified chlamydial antigen delivery platforms. As the mechanisms engaged in the pathology of the disease are not fully understood, designing a subunit vaccine specific to chlamydial antigens could improve safety for human use. We propose the delivery of chlamydia-specific antigens to the ocular mucosa using particulate carriers, bacterial ghosts (BGs). We therefore characterized humoral and cellular immune responses after conjunctival and subcutaneous immunization with a N-terminal portion (amino acid 1–893) of the chlamydial polymorphic membrane protein C (PmpC) of Ct serovar B, expressed in probiotic Escherichia coli Nissle 1917 bacterial ghosts (EcN BGs) in BALB/c mice. Three immunizations were performed at two-week intervals, and the immune responses were evaluated two weeks after the final immunization in mice. In a guinea pig model of ocular infection animals were immunized in the same manner as the mice, and protection against challenge was assessed two weeks after the last immunization. N-PmpC was successfully expressed within BGs and delivery to the ocular mucosa was well tolerated without signs of inflammation. N-PmpC-specific mucosal IgA levels in tears yielded significantly increased levels in the group immunized via the conjunctiva compared with the subcutaneously immunized mice. Immunization with N-PmpC EcN BGs via both immunization routes prompted the establishment of an N-PmpC-specific IFNγ immune response. Immunization via the conjunctiva resulted in a decrease in intensity of the transitional inflammatory reaction in conjunctiva of challenged guinea pigs compared with subcutaneously and non-immunized animals. The delivery of the chlamydial subunit vaccine to the ocular mucosa using a particulate carrier, such as BGs, induced both humoral and cellular immune responses. Further investigations are needed to improve the immunization scheme and dosage.     

Weakly supervised learning and interpretability for endometrial whole slide image diagnosis

Fully supervised learning for whole slide image–based diagnostic tasks in histopathology is problematic due to the requirement for costly and time-consuming manual annotation by experts. Weakly supervised learning that utilizes only slide-level labels during training is becoming more widespread as it relieves this burden, but has not yet been applied to endometrial whole slide images, in iSyntax format. In this work, we apply a weakly supervised learning algorithm to a real-world dataset of this type for the first time, with over 85% validation accuracy and over 87% test accuracy. We then employ interpretability methods including attention heatmapping, feature visualization, and a novel end-to-end saliency-mapping approach to identify distinct morphologies learned by the model and build an understanding of its behavior. These interpretability methods, alongside consultation with expert pathologists, allow us to make comparisons between machine-learned knowledge and consensus in the field. This work contributes to the state of the art by demonstrating a robust practical application of weakly supervised learning on a real-world digital pathology dataset and shows the importance of fine-grained interpretability to support understanding and evaluation of model performance in this high-stakes use case.     

Five-years cumulative incidence of alcohol consumption in Croatian adult population: the CroHort study

Alcohol consumption is traditionally part of most human cultures, and with the onset of industrial revolution it was recognized as a health and social problem. The aim of this article is to investigate cumulative incidence of alcohol consumption in Croatia. Data were obtained from the Croatian Adult health Survey in 2003 followed by 2008. The cohort consisted of 3229 participants. Questions regarding alcohol consumption were calculated into two factors describing existence or non-existence of risk behavior. Results revealed higher incidence of risk alcohol consumption in man than in women and highest in the 35-65, age group. Due to the some study limitations results might be underestimated. Present problem of alcohol is alarming, even more so, in women's population it might be only the tip of the iceberg. Cultural and regional differences should be taken into account when educational programs are constructed, especially due to the different type of alcohol consumed.