Elastase of U-937 Monocytelike Cells: COMPARISONS WITH ELASTASES DERIVED FROM HUMAN MONOCYTES AND NEUTROPHILS AND MURINE MACROPHAGELIKE CELLS

As an approach to facilitating the understanding of proteinases associated with monocytes we have studied U-937 monocytelike cells. Elastase activity was identified in U-937 cell extracts and compared to monocyte elastase activity, neutrophil elastase, and the elastase activity from a continuous line of murine macrophagelike cells (P388D1). Serine proteinase activity which solubilized ¹⁴C-labeled elastin accounted for >90% of the neutral proteinase activity of both U-937 cells and monocyte extracts. U-937 cell and monocyte elastase activities were similar catalytically, resembling neutrophil elastase. U-937 cells and monocytes showed other similarities: (a) both had activities reacting with [³H]diisopropylfluorophosphate that migrated in sodium dodecyl sulfate (SDS) polyacrylamide gels at ~30,000 and 60,000 daltons and (b) both contained material that cross-reacted with antiserum raised to neutrophil elastase. Preliminary characterization of U-937 cell elastase activity by affinity chromatography and ion-exchange chromatography suggested the presence of at least two distinct elastases. Minimal elastase activity was found in U-937 cell-conditioned medium, indicating that the activity is not spontaneously released by the cells. In contrast to the elastase activity associated with U-937 cells and monocytes, the elastase activity associated with P388D1 cells was a metalloproteinase and was found principally in the culture medium. These results indicate (a) U-937 cells will be useful for further investigation of proteinases associated with normal monocytes; (b) monocytes and U-937 cells contain material with catalytic and immunologic similarities to neutrophil elastase; (c) monocyte elastase activity differs from elastase activity secreted by murine macrophages and murine macrophagelike cells of the P388D1 line.     

Interruption of the enterohepatic circulation of digitoxin by cholestyramine: II. Effect on metabolic disposition of tritium-labeled digitoxin and cardiac systolic intervals in man

Previous studies of digitalis glycoside metabolism and excretion have indicated that these compounds undergo a significant enterohepatic cycle in some species. It has been suggested that the existence of such a cycle in man contributes to the prolonged action of certain cardiac glycosides. Previous studies have demonstrated that cholestyramine binds digitoxin and digoxin in vitro and accelerates the metabolic disposition of digitoxin in rats and guinea pigs, presumably by interrupting the enterohepatic circulation.In order to assess the role of the enterohepatic circulation in the metabolism of digitalis glycosides in humans, maintenance doses of cholestyramine were administered to 7 of 15 normal human subjects beginning 8 hr after digitalization with 1.2 mg of digitoxin-(3)H. All subjects had frequent measurements of serum radioactivity, left ventricular ejection time (LVET), and electromechanical systole (QS(2)), the latter recorded as the interval from onset of Q wave to first major component of second heart sound. Measurement of the LVET and QS(2) intervals affords a sensitive index of the cardiac response to digitalis. In addition, chloroform extraction of serum was performed to separate unchanged digitoxin and active metabolites from cardioinactive metabolites of digitoxin. Cholestyramine treatment resulted in reduction in half-life to total serum radioactivity from 11.5 to 6.6 days, and in chloroform-extractable radioactivity from 6.0 to 4.5 days, as compared to controls. In addition, cholestyramine treatment was accompanied by more rapid return to base line values of digitoxin-induced changes in the LVET and QS(2) intervals. A significant positive correlation was found between QS(2) values and chloroform-extractable radioactivity, the latter reflecting unchanged digitoxin-H(3) (r=0.64; P=<0.01).The results indicate that administration of cholestyramine to digitalized human subjects accelerates the metabolic disposition of digitoxin and abbreviates the physiologic response to the glycoside. This effect is presumably mediated by interruption of the enterohepatic circulation of digitoxin by cholestyramine.     

In vivo imaging of radiation-induced tissue apoptosis by <Superscript>99m</Superscript>Tc(I)-his<Subscript>6</Subscript>-annexin A5

Objective  

A recombinant annexin A5 with the N-terminal extension of six histidine residues was labeled with ^99mTc(I)-tricarbonyl ion to produce the ^99mTc-labeled annexin A5, referred to ^99mTc(I)-his₆-annexin A5. We have explored the agent as an effective imaging probe for in vivo detecting the apoptosis of internal tissue subjected with high radiation doses in a γ-irradiated mouse model.     

POLYFUNCTIONAL DINITROPHENYL HAPTENS AS REAGENTS FOR ELICITATION OF IMMEDIATE TYPE ALLERGIC SKIN RESPONSES

Dinitrophenyl derivatives of differing molecular weights and degrees of substitution have been contrasted with respect to their ability to elicit immediate type allergic responses and their capacity to induce antibody formation in the guinea pig. In contradistinction to dinitrophenyl-proteins, bis-DNP-lysine and DNP-polylysines (including a 100,000 molecular weight derivative) failed to induce antibody detectable by guinea pig passive cutaneous anaphylaxis. Dinitrophenyl-polylysines evoked urticarial responses non-specifically, but after succinylation were about as effective as dinitrophenyl-proteins in eliciting specific cutaneous reactions. An important factor influencing the effectiveness of bis-DNP-lysine in evoking specific wheal-and-erythema responses is antibody affinity for the dinitrophenyl-lysyl determinant.     

INDUCTION OF TUMORS IN DOMESTIC RABBITS WITH NUCLEIC ACID PREPARATIONS FROM PARTIALLY PURIFIED SHOPE PAPILLOMA VIRUS AND FROM EXTRACTS OF THE PAPILLOMAS OF DOMESTIC AND COTTONTAIL RABBITS

A deoxyribonucleic acid preparation which showed infectivity and tumorigenic activity in domestic rabbits was isolated from the papillomatous tissue of wild cottontail rabbits by phenolic deproteinization procedure. The activity of the preparation could be completely abolished by its exposure to a minute amount (0.02 µg/ml) of DNAase. Antisera against Shope papilloma virus did not block the tumorigenic activity of the preparation, and trypsin and chymotrypsin had no effect on it. The extraction with phenol of a partially purified virus preparation also yielded extracts with tumorigenic potency. Extracts obtained from the domestic rabbit papilloma and submitted to phenolic deproteinization also proved infective and tumorigenic in rabbits of this sort, although the level of "tumorigenicity" was much lower than that of the cottontail preparations. Tests for intact virus, carried out with half of the extracts yielded wholly negative findings.     

3D intra-operative ultrasound and MR image guidance: pursuing an ultrasound-based management of brainshift to enhance neuronavigation

Background

Brainshift is still a major issue in neuronavigation. Incorporating intra-operative ultrasound (iUS) with advanced registration algorithms within the surgical workflow is regarded as a promising approach for a better understanding and management of brainshift. This work is intended to (1) provide three-dimensional (3D) ultrasound reconstructions specifically for brain imaging in order to detect brainshift observed intra-operatively, (2) evaluate a novel iterative intra-operative ultrasound-based deformation correction framework, and (3) validate the performance of the proposed image-registration-based deformation estimation in a clinical environment.

Methods

Eight patients with brain tumors undergoing surgical resection are enrolled in this study. For each patient, a 3D freehand iUS system is employed in combination with an intra-operative navigation (iNav) system, and intra-operative ultrasound data are acquired at three timepoints during surgery. On this foundation, we present a novel resolution-preserving 3D ultrasound reconstruction, as well as a framework to detect brainshift through iterative registration of iUS images. To validate the system, the target registration error (TRE) is evaluated for each patient, and both rigid and elastic registration algorithms are analyzed.

Results

The mean TRE based on 3D-iUS improves significantly using the proposed brainshift compensation compared to neuronavigation (iNav) before (2.7 vs. 5.9 mm; \(p=0.001\)) and after dural opening (4.2 vs. 6.2 mm, \(p=0.049\)), but not after resection (6.7 vs. 7.5 mm; \(p=0.426\)). iUS depicts a significant (\(p=0.001\)) dynamic spatial brainshift throughout the three timepoints. Accuracy of registration can be improved through rigid and elastic registrations by 29.2 and 33.3%, respectively, after dural opening, and by 5.2 and 0.4%, after resection.

Conclusion

3D-iUS systems can improve the detection of brainshift and significantly increase the accuracy of the navigation in a real scenario. 3D-iUS can thus be regarded as a robust, reliable, and feasible technology to enhance neuronavigation.

     

CT-based automated planning of acetabular cup for total hip arthroplasty (THA) based on hybrid use of two statistical atlases

Purpose

This study describes the use of CT images in atlas-based automated planning methods for acetabular cup implants in total hip arthroplasty (THA). The objective of this study is to develop an automated cup planning method considering the statistical distribution of the residual thickness.

Methods

From a number of past THA planning datasets, we construct two statistical atlases that represent the surgeon’s expertise. The first atlas is a pelvis-cup merged statistical shape model (PC-SSM), which encodes global spatial relationships between the patient anatomy and implant. The other is a statistical residual thickness map (SRTM) of the implant surface, which encodes local spatial constraints of the anatomy and implant. In addition to PC-SSM and SRTM, we utilized the minimum thickness as a threshold constraint to prevent penetration.

Results

The proposed method was applied to the pelvis shapes segmented from CT images of 37 datasets of osteoarthritis patients. Automated planning results with manual segmentation were compared to the plans prepared by an experienced surgeon. There was no significant difference in the average cup size error between the two methods (1.1 and 1.2 mm, respectively). The average positional error obtained by the proposed method, which integrates the two atlases, was significantly smaller (3.2 mm) than the previous method, which uses single atlas (3.9 mm). In the proposed method with automated segmentation, the size error of the proposed method for automated segmentation was comparable (1.1 mm) to that for manual segmentation (1.1 mm). The average positional error was significantly worse (4.2 mm) than that using manual segmentation (3.2 mm). If we only consider mildly diseased cases, however, there was no significance between them (3.2 mm in automated and 2.6 mm in manual segmentation).

Conclusion

We infer that integrating PC-SSM and SRTM is a useful approach for modeling experienced surgeon’s preference during cup planning.

     

Risk factors for post-traumatic stress disorder symptoms following critical illness requiring mechanical ventilation: a prospective cohort study

Introduction  

Post-traumatic stress disorder (PTSD) has been identified in a significant portion of intensive care unit (ICU) survivors. We sought to identify factors associated with PTSD symptoms in patients following critical illness requiring mechanical ventilation.     

Extracorporeal liver support: a continuing challenge

Given that liver failure continues to pose an enormous clinical challenge, the concept of hepatic dialysis has enjoyed significant interest. In particular, many investigations have examined the therapeutic mechanisms and efficacy of artificial albumin dialysis based systems in acute on chronic liver failure, the results of which have been conflicting. Albumin dialysis systems do not appear to significantly decrease serum concentrations of inflammatory cytokines in severe acute on chronic liver failure. Thus, if these treatments do result in clinical improvement, then other therapeutic mechanisms must be involved.