Activation of type IV procollagenases by human tumor-associated trypsin-2

Increased production of proteinases, such as matrix metalloproteinases (MMPs), is a characteristic feature of malignant tumors. Some human cancers and cell lines derived from them also express trypsinogen, but the function of the extrapancreatic trypsin has remained unclear. In this study we cloned and sequenced trypsinogen-2 cDNA from human COLO 205 colon carcinoma cells and characterized the ability of the enzyme to activate latent human type IV procollagenases (proMMP-2 and proMMP-9). As shown by cloning and N-terminal amino acid sequencing, the amino acid sequence of tumor-associated trypsin-2 is identical to that of pancreatic trypsin-2. We found that both pancreatic trypsin-2 and tumor cell-derived trypsin-2 are efficient activators of proMMP-9 and are capable of activating proMMP-9 at a molar ratio of 1:1000, the lowest reported so far. Human trypsin-2 was a more efficient activator than widely used bovine trypsin and converted the 92-kDa proMMP-9 to a single 77-kDa product that was not fragmented further. The single peptide bond cleaved by trypsin-2 in proMMP-9 was Arg87-Phe88. The generation of the 77-kDa species coincided with the increase in specific activity of MMP-9. In contrast, trypsin-2 only partially activated proMMP-2. Trypsin-2 cleaved the Arg99-Lys100 peptide bond of proMMP-2 generating 62-65-kDa MMP-2 species. Trypsin-2-induced proMMP-2 and -9 conversions were inhibited by tumor-associated trypsin inhibitor added either prior to or during activation indicating that proMMPs were not activated autocatalytically. Trypsin-2 also activated proMMPs associated with tissue inhibitor of matrix metalloproteinases, the complexes of which are thought to be the major MMP forms in vivo. The ability of human tumor cell-derived trypsin-2 to activate latent MMPs suggests a role for trypsin-2 in initiating the proteinase cascade that mediates tumor invasion and metastasis formation.     

Prediction of posttraumatic stress disorder by immediate reactions to trauma: a prospective study in road traffic accident victims

Road traffic accidents often cause serious physical and psychological sequelae. Specialists of various medical faculties are involved in the treatment of accident victims. Little is known about the factors which might predict psychiatric disorders, e.g. Posttraumatic Stress Disorder (PTSD) after accidents and how psychological problems influence physical treatment. In a prospective study 179 unselected, consecutively admitted road traffic accident victims were assessed a few days after the accident for psychiatric diagnoses, severity of injury and psychopathology. All were inpatients and had to be treated for bone fractures. At 6-months follow-up assessment 152 (85%) of the patients were interviewed again. Of the patients, 18.4% fulfilled the criteria for Posttraumatic Stress Disorder (DSM-III-R) within 6 months after the accident. Patients who developed PTSD were injured more severely and showed more symptoms of anxiety, depression and PTSD a few days after the accident than patients with no psychiatric diagnosis. Patients with PTSD stayed significantly longer in the hospital than the other patients. Multiple regression analysis revealed that the length of hospitalization was due mainly to a diversity of factors such as severity of injury, severity of accident, premorbid personality and psychopathology. Posttraumatic stress disorder is common after road traffic accidents. Patients with PTSD at follow-up can be identified by findings from early assessment. Untreated psychological sequelae such as PTSD cause longer hospitalization and therefore more costs than in non-PTSD patients.     

Early views of the martian surface from the Mars Orbiter Camera of Mars Global Surveyor

High-resolution images of the martian surface at scales of a few meters show ubiquitous erosional and depositional eolian landforms. Dunes, sandsheets, and drifts are prevalent and exhibit a range of morphology, composition (inferred from albedo), and age (as seen in occurrences of different dune orientations at the same location). Steep walls of topographic depressions such as canyons, valleys, and impact craters show the martian crust to be stratified at scales of a few tens of meters. The south polar layered terrain and superposed permanent ice cap display diverse surface textures that may reflect the complex interplay of volatile and non-volatile components. Low resolution regional views of the planet provide synoptic observations of polar cap retreat, condensate clouds, and the lifecycle of local and regional dust storms.     

Chloride conduction of nasal fibroblasts in polyposis patients with cystic fibrosis and in patients without cystic fibrosis. Relevance for the ENT physician]

Cystic fibrosis (CF) is a complex systemic disease that has pathological alterations in the upper airways, including the recurrent formation of nasal polyps. Although the fibroblast is the predominant cell type in nasal stroma and nasal polyps, little is known about the electrophysiological properties of nasal fibroblasts. We investigated whether fibroblasts possess a cAMP-regulated chloride conductance which is impaired in patients with CF. Thus far the few studies concerning conductance in fibroblasts have been performed on skin fibroblasts using indirect methods and have yielded conflicting results. Therefore we studied chloride conductance in fused nasal fibroblasts by employing conventional microelectrodes. We have demonstrated that a cAMP-regulated chloride conductance is present in fibroblasts. However, this chloride conductance cannot be activated in fibroblasts from CF-patients. Thus, we present direct evidence that the impairment of the cAMP-regulated chloride conductance in CF is not confined to epithelial cells but also affects the fibroblast. We discuss how this conductance might modulate fibroblast proliferation to produce polyp formation.     

Matrix metalloproteinase (MMP)-9 type IV collagenase/gelatinase implicated in the pathogenesis of Sj?gren''s syndrome

Integrin-ligand binding generates many intracellular signals, including signals to initiate focal contact formation and to regulate cellular decisions concerning growth and differentiation. Oligomerization of the beta subunit cytoplasmic domain appears to be required for many of these events. In order to study these processes, we have generated a novel chimeric protein, consisting of the chicken integrin beta 1 cytoplasmic domain connected to the central rod domain of a neuronal intermediate filament, alpha-internexin. This chimeric protein, when expressed transiently in 293T cells, oligomerizes in a beta cytoplasmic domain-dependent manner. This oligomerization requires the membrane proximal amino acids LLMII of the beta 1 cytoplasmic domain, as demonstrated by deletion analysis. Therefore, the integrin beta cytoplasmic domain in this system contains an oligomerization function, which may provide some insight as to the function of intact integrins in vivo.     

Hematopoietic progenitor cell rolling in bone marrow microvessels: parallel contributions by endothelial selectins and vascular cell adhesion molecule 1

1,2-Naphthoquinones, such as beta-lapachone, 4-alkoxy-1,2-naphthoquinones, and tetrahydrofuran-1,2-naphthoquinones, react rapidly with 2-mercaptoethanol in benzene to give 1,4-, 1,2-, 1,3- and 1,6-Michael-type adducts that are formed by the addition of the thiol group to the quinone ring. Menadione (2-methyl-1,4-naphthoquinone) reacts with the thiol reagent very slowly under the same reaction conditions. Although the formation of the adducts can be followed by 1H-NMR, attempts to isolate the adducts failed due to their retroconversion to the starting products. On addition of a Lewis acid, however, the adducts undergo cyclization reactions that give stable derivatives that can be isolated and characterized. Determination of the structures of the derivatives allowed for the identification of the adducts from which they originated. Thus, beta-lapachone and 2,3-dinordunnione underwent 1,4- and 1,2-Michael type additions to the quinone ring, while 4-pentyloxy-1,2-naphthoquinone underwent two simultaneous Michael additions to the quinone ring of the naphthoquinone. Menadione underwent a single 1,3-addition. The alkylation rates of the thiol group of 2-mercaptoethanol by the naphthoquinones parallel the naphthoquinones efficiencies in inducing DNA cleavage through DNA-bound topoisomerase II. These results support our hypothesis that the cytotoxic effect of the naphthoquinones derive, at least in part, from their alkylation of exposed thiol residues on the topoisomerase II-DNA complex.     

Axial loading of the spine during CT and MR in patients with suspected lumbar spinal stenosis

PURPOSE: To evaluate the effect of compressive axial loading in imaging of the lumbar spine in patients with clinically suspected spinal stenosis. MATERIAL AND METHODS: A total of 84 patients were examined, 50 with CT (after intrathecal contrast administration) and 34 with MR. First the dural sac cross-sectional area (CSA) was determined with the patient in the supine psoas relaxed position (PRP). Then the CSA was determined during supine axial compression in slight extension (ACE), obtained with a specially designed loading device. A measurement error study was performed. RESULTS: A minimum difference in CSA of 15 mm2 between PRP and ACE was found to be significant. In 40/50 (80%) of CT-examined patients and in 26/34 (76%) of MR-examined patients a significant difference in CSA was found. In 25/84 (30%) of the patients there was a significant difference at more than one level. CONCLUSION: For an adequate evaluation of the CSA, CT or MR studies should be performed with axial loading in patients who have symptoms of lumbar spinal stenosis.     

Necessary and sufficient conditions for constraint satisfaction in switched systems using switch‐robust control invariant sets

This paper studies the control of constrained systems whose dynamics and constraints switch between a finite set of modes over time according to an exogenous input signal. We define a new type of control invariant sets for switched constrained systems, called switch–robust control invariant (switch‐RCI) sets, that are robust to unknown mode switching and exploit available information on minimum dwell‐time and admissible mode transitions. These switch‐RCI sets are used to derive novel necessary and sufficient conditions for the existence of a control‐law that guarantees constraint satisfaction in the presence of unknown mode switching with known minimum dwell‐time. The switch‐RCI sets are also used to design a recursively feasible model predictive controller (MPC) that enforces closed‐loop constraint satisfaction for switched constrained systems. We show that our controller is nonconservative in the sense that it enforces constraints on the largest possible domain, ie, constraints can be recursively satisfied if and only if our controller is feasible. The MPC and switch‐RCI sets are demonstrated on a vehicle lane‐changing case study.     

Fiber-optic ellipsoidal flextensional hydrophones

Calculations of circumferential strain, polar and equatorial displacement, lowest natural frequency, buckling pressure, and optical pressure sensitivity for an oblate-spheroidal-shell fiber optic hydrophone are presented using the theory for thin shells. Sample designs based on these calculations are compared to other fiber-optic hydrophone designs of similar dimensions and materials. A prolate-spheroidal-shell hydrophone design is also presented