Dynamics of the expression of intermediate filaments vimentin and desmin during myofibroblast differentiation after corneal injury

Previous studies have suggested that abnormal corneal wound healing in patients after photorefractive keratectomy (PRK) is associated with the appearance of myofibroblasts in the stroma between two and four weeks after surgery. The purpose of this study was to examine potential myofibroblast progenitor cells that might express other filament markers prior to completion of the differentiation pathway that yields a-smooth muscle actin (SMA)-expressing myofibroblasts associated with haze localized beneath the epithelial basement membrane after PRK. Twenty-four female rabbits that had -9 diopter PRK were sacrificed at I week, 2 weeks, 3 weeks or 4 weeks after surgery. Corneal rims were collected, frozen at -80 degrees C, and analyzed by immunocytochemistry using anti-vimentin, anti-desmin, and anti-SMA antibodies. Double immunostaining was performed for the co-localization of SMA with vimentin or desmin with SMA. An increase in vimentin expression in stromal cells is noted as early as 1 week after PRK in the rabbit cornea. As the healing response continues at two or three weeks after surgery, many stromal cells expressing vimentin also begin to express desmin and SMA. By 4 weeks after the surgery most, if not all, myofibroblasts express vimentin, desmin and SMA. Generalized least squares regression analysis showed that there was strong evidence that each of the marker groups differed in expression over time compared to the other two (p < 0.01). Intermediate filaments - vimentin and desmin co-exist in myofibroblasts along with SMA and may play an important role in corneal remodeling after photorefractive keratectomy. The earliest precursors of myofibroblasts destined to express SMA and desmin are detectible by staining for vimentin at I week after surgery. (C) 2009 Elsevier Ltd. All rights reserved.

Abdominal compartment syndrome in trauma resuscitation

Purpose of review Swelling is inexorably linked to shock and resuscitation in trauma. In many forms, swelling complicates and interacts with traumatic injury to raise pressures in the abdomen, resulting in intraabdominal hypertension, which may overtly manifest as abdominal compartment syndrome (ACS) driving multiple organ failure. Despite renewed clinical interest in posttraumatic intraabdominal pressure, there remains a chiasm between knowledge of the risks and clinical interventions to mitigate them. This review provides a concise overview of definitions, risk factors, diagnosis and management using an illustrative trauma case. Recent findings Intraabdominal pressure commonly increases following trauma, wherein ACS may manifest earlier than generally appreciated and complicate other insults such as shock and hemorrhage. Contemporary resuscitation strategies may exacerbate intraabdominal hypertension, particularly massive crystalloid resuscitation. Although unproven, the recent transition to crystalloid restriction and high plasma resuscitation strategies may influence the prevalence of ACS. Nonetheless, aggressive intraabdominal pressure monitoring should be mandatory in the critically ill. Despite potential nonoperative options, decompressive laparotomy remains the only definitive but often morbid treatment. Summary ACS results from many dysfunctions acting in concert with each other in self-propagating vicious cycles. Starting with greater awareness, it is imperative that the growing knowledge should be translated into clinical practice.

The association of prevalent medial meniscal pathology with cartilage loss in the medial tibiofemoral compartment over a 2-year period

Objective: To investigate the association of different types of magnetic resonance imaging (MRI)-detected medial meniscal pathology with subregional cartilage loss in the medial tibiofemoral compartment. Methods: A total of 152 women aged >= 40 years, with and without knee osteoarthritis (OA) were included in a longitudinal 24-month observational study. Spoiled gradient recalled acquisitions at steady state (SPGR) and T2-weighted fat-suppressed MRI sequences were acquired. Medial meniscal status of the anterior horn (AH), body, and posterior horn (PH) was graded at baseline: 0 (normal), 1 (intrasubstance meniscal signal changes), 2 (single tears), and 3 (complex tears/maceration). Cartilage segmentation was performed at baseline and 24-month follow-up in various tibiofemoral subregions using computation software. Multiple linear regression models were applied for the analysis with cartilage loss as the outcome. In a first model, the results were adjusted for age and body mass index (BMI). In a second model, the results were adjusted for age, BMI and medial meniscal extrusion. Results: After adjusting for age, BMI, and medial meniscal extrusion, cartilage loss in the total medial tibia (MT) (0.04 mm, P=0.04) and the external medial tibia (eMT) (0.068 mm, P=0.04) increased significantly for compartments with grade 3 lesions. Cartilage loss in the total central medial femoral condyle (cMF) (0.071 mm, P=0.03) also increased significantly for compartments with grade 2 lesions. Cartilage loss at the eMT was significantly related to tears of the PH (0.074 mm; P=0.03). Cartilage loss was not significantly increased for compartments with grade 1 lesions. Conclusion: The protective function of the meniscus appears to be preserved in the presence of intrasubstance meniscal signal changes. Prevalent single tears and meniscal maceration were found to be associated with increased cartilage loss in the same compartment, especially at the PH. (C) 2009 Osteoarthritis Research Society International. Published by Elsevier Ltd. All rights reserved.

Upregulation of intermediate calcium-activated potassium channels counterbalance the impaired endothelium-dependent vasodilation in stroke-prone spontaneously hypertensive rats

Endothelial dysfunction has been linked to a decrease in nitric oxide (NO) bioavailability and attenuated endothelium-derived hyperpolarizing factor (EDHF)-mediated relaxation. The small (SK(Ca)) and intermediate (IK(Ca)) calcium-activated potassium channels play a key role in endothelium-dependent relaxation. Because the repressor element 1-silencing transcription factor (REST) negatively regulates IK(Ca) expression, we hypothesized that augmented REST and decreased IK(Ca) expression contributes to impaired endothelium-dependent vasodilation associated with hypertension. Acetylcholine (ACh) responses were slightly decreased in small mesenteric arteries from male stroke-prone spontaneously hypertensive rats (SHRSPs) versus arteries from Wistar Kyoto (WKY) rats. Incubation with N-nitro-L-arginine methyl ester (L-NAME; 100 mu mol/L) and indomethacin (100 mu mol/L) greatly impaired ACh responses in vessels from SHRSP. lberiotoxin (0.1 mu mol/L), which is a selective inhibitor of large-conductance K(Ca) (BK(Ca)) channels, did not modify EDHF-mediated vasodilation in SHRSP or WKY. UCL-1684 (0.1 mu mol/L.), which is a selective inhibitor of SKCa channels, almost abolished EDHF-mediated vasodilation in WKY and decreased relaxation in SHRSP. 1-((2-chlorophenyl)diphenylmethyl)-1H-pyrazole (TRAM-34; 10 mu mol/L) and charybdotoxin (0.1 mu mol/L), which are both IKCa inhibitors, produced a small decrease of EDHF relaxation in WKY but completely abrogated EDHF vasodilation in SHRSP. EDHF-mediated relaxant responses were completely abolished in both groups by simultaneous treatment with UCL-1684 and TRAM-34 or charybdotoxin. Relaxation to SK(Ca)/IK(Ca) channels agonist NS-309 was decreased in SHRSP arteries. The expression of SK(Ca) was decreased, whereas IK(Ca) was increased in SHRSP mesenteric arteries. REST expression was reduced in arteries from SHRSP. Vessels incubated with TRAM-34 (10 mu mol/L) for 24h displayed reduced REST expression and demonstrated no differences in IK(Ca). In conclusion, IK(Ca) channel upregulation, via decreased REST, seems to compensate deficient activity of SK(Ca) channels in the vasculature of spontaneously hypertensive rats. (Translational Research 2009; 154:183-193)

Further studies on an intermediate host murine model showing that a primary Echinococcus granulosus infection is protective against subsequent oncospheral challenge

We describe the use of a murine model to evaluate resistance against subsequent challenge following a primary infection with oncospheres of Echinococcus granulosus. Mice (Kunming strain) were infected with hatched oncospheres of Echinococcus granulosus; 21 days later a second challenge was given by a different route of infection. A primary infection by intraperitoneal (i.p.) injection stimulated 100 and 90.5% protection in terms of reduced cyst numbers against a secondary infection given subcutaneously (s.c.) or intravenously (i.v.) respectively. A primary infection given s.c. followed by i.p. or i.v. challenge resulted in 84.0 and 100% protection, respectively. Intravenous infection followed by i.p. or s.c. challenge resulted in 98.5 and 69.4% protection, respectively. With the i.v. route of infection, almost all resultant cysts were present in the lungs. The data show that a primary infection with oncospheres can induce total or a high degree of protection against a subsequent challenge and confirms that natural (concomitant) immunity can be stimulated in the intermediate host as the result of a primary infection. This may explain the decline in hydatid infection in sheep older than 2 years in hyper-endemic areas such as those found in Xingjiang, China. These older sheep may have been earlier infected and have subsequently self-cured, with the primary infection stimulating an immune response that protects the intermediate host animals from further infection. (C) 2001 Elsevier Science Ireland Ltd. All rights reserved.

Is the irritable bladder associated with anterior compartment relaxation? A critical look at the 'integral theory of pelvic floor dysfunction'

The 'integral theory of pelvic floor dysfunction', first proposed by Petros and Ulmsten in 1990, claims that anterior vaginal wall relaxation is associated with symptoms of urgency, frequency, nocturia and urge incontinence. A retrospective study was designed to test this hypothesis. Imaging data and urodynamic reports from 272 women suffering from symptoms of lower urinary tract dysfunction were evaluated. Opening of the retrovesical angle, bladder neck descent, urethral rotation and descent of a cystocele during Valsalva were used to quantify anterior vaginal wall laxity None of the tested parameters were associated with symptoms and signs of detrusor overactivity. On the contrary, patients with higher grades of urethral and bladder descent were less likely to suffer from nocturia and urge incontinence and were less likely to leave sensory urgency and detrusor instability diagnosed on urodynamic testing. The findings of this study therefore do not support this hypothesis of the 'integral theory'.

A novel 14-kilodalton protein interacts with the mitogen-activated protein kinase scaffold MP1 on a late endosomal/lysosomal compartment

We have identified a novel, highly conserved protein of 14 kD copurifying with late endosomes/lysosomes on density gradients. The protein, now termed p14, is peripherally associated with the cytoplasmic face of late endosomes/lysosomes in a variety of different cell types. In a two-hybrid screen with p14 as a bait, we identified the mitogen-activated protein kinase (MAPK) scaffolding protein MAPK/extracellular signal-regulated kinase (ERK) kinase (MEK) partner 1 (MP1) as an interacting protein. We confirmed the specificity of this interaction in vitro by glutathione S-transferase pull-down assays and by coimmunoprecipitation, cosedimentation on glycerol gradients, and colocalization. Moreover, expression of a plasma membrane-targeted p14 causes mislocalization of coexpressed MP1. In addition, we could reconstitute protein complexes containing the p14-MP1 complex associated with ERK and MEK in vitro. The interaction between p14 and MP1 suggests a MAPK scaffolding activity localized to the cytoplasmic surface of late endosomes/lysosomes, thereby combining catalytic scaffolding and subcellular compartmentalization as means to modulate MAPK signaling within a cell.

The Phox Homology (PX) domain-dependent, 3-phosphoinositide-mediated association of sorting nexin-1 with an early sorting endosomal compartment is required for its ability to regulate epidermal growth factor receptor degradation

Recent studies have shown that phox homology (PX) domains act as phosphoinositide-binding motifs. The majority of PX domains studied show binding to phosphatidylinositol 3-monophosphate (Ptdlns(3)P), an association that allows the host protein to localize to membranes of the endocytic pathway. One issue, however, is whether PX domains may have alternative phosphoinositide binding specificities that could target their host protein to distinct subcellular compartments or allow their allosteric regulation by phosphoinositides other than PtdIns(3)P. It has been reported that the PX domain of sorting nexin 1 (SNX1) specifically binds phosphatidylinositol 3,4,5-trisphosphate (PtdIns(3,4,5)P-3) (Zhong, Q., Lazar, C. S., Tronchere, H., Sato, T., Meerloo, T., Yeo, M., Songyang, Z., Emr, S. D., and Gill, G. N. (2002) Proc. Natl. Acad. Sci. U. S. A. 99,6767-6772). In the present study, we have shown that whereas SNX1 binds PtdIns(3,4,5)P-3 in protein:lipid overlay assays, in liposomes-based assays, binding is observed to PtdIns(3)P and phosphatidylinositol 3,5-bisphosphate (PtdIns(3,5)P-2) but not to PtdIns(3,4,5)P-3. To address the significance of PtdIns(3,4,5)P-3 binding, we examined the subcellular localization of SNX1 under conditions in which plasma membrane PtdIns(3,4,5)P-3 levels were significantly elevated. Under these conditions, we failed to observe association of SNX1 with this membrane. However, consistent with the binding to PtdIns(3)P and PtdIns(3,5)P-2 being of more physiological significance was the observation that the association of SNX1 with an early endosomal compartment was dependent on a 3-phosphoinositide-binding PX domain and the presence of PtdIns(3)P on this compartment. Finally, we somal association of SNX1 is important for its ability to regulate the targeting of internalized epidermal growth factor receptor for lysosomal degradation.

Use of an accelerated chest pain assessment protocol in patients at intermediate risk of adverse cardiac events

Objective: To determine the feasibility, safety and effectiveness of a structured clinical pathway for stratification and management of patients presenting with chest pain and classified as having intermediate risk of adverse cardiac outcomes in the subsequent six months. Design: Prospective clinical audit. Participants and setting: 630 consecutive patients who presented to the emergency department of a metropolitan tertiary care hospital between January 2000 and June 2001 with chest pain and intermediate-risk features. Intervention: Use of the Accelerated Chest Pain Assessment Protocol (ACPAP), as advocated by the Management of unstable angina guidelines - 2000 from the National Heart Foundation and the Cardiac Society of Australia and New Zealand. Main outcome measure: Adverse cardiac events during six-month follow-up. Results: 409 patients (65%) were reclassified as low risk and discharged at a mean of 14 hours after assessment in the chest pain unit. None had missed myocardial infarctions, while three (1%) had cardiac events at six months (all elective revascularisation procedures, with no readmissions with acute coronary syndromes). Another 110 patients (17%) were reclassified as high risk, and 21 (19%) of these had cardiac events (mainly revascularisations) by six months. Patients who were unable to exercise or had non-diagnostic exercise stress test results (equivocal risk) had an intermediate cardiac event rate (8%). Conclusions: This study validates use of ACPAP. The protocol eliminated missed myocardial infarction; allowed early, safe discharge of low-risk patients; and led to early identification and management of high-risk patients.

Convex optimization framework for intermediate deadline assignment in soft and hard real-time distributed systems

It is generally challenging to determine end-to-end delays of applications for maximizing the aggregate system utility subject to timing constraints. Many practical approaches suggest the use of intermediate deadline of tasks in order to control and upper-bound their end-to-end delays. This paper proposes a unified framework for different time-sensitive, global optimization problems, and solves them in a distributed manner using Lagrangian duality. The framework uses global viewpoints to assign intermediate deadlines, taking resource contention among tasks into consideration. For soft real-time tasks, the proposed framework effectively addresses the deadline assignment problem while maximizing the aggregate quality of service. For hard real-time tasks, we show that existing heuristic solutions to the deadline assignment problem can be incorporated into the proposed framework, enriching their mathematical interpretation.

Melanoides tuberculatus (Gastropoda: Thiaridae) as intermediate host of Heterophyidae (Trematoda: Digenea) in Rio de Janeiro metropolitan area, Brazil

In the late 1960s, Melanoides tuberculatus snails were introduced in Brazil from North/East Africa and Southeast Asia. The first records of specimens infected with cercariae were registered in Rio de Janeiro State in 2001. The present study reports the occurrence of M. tuberculatus infected with larval trematodes in Rio de Janeiro City. Bottom sediment was collected with dip nets and sieved through 0.25 inch-mesh screening. Snails were transported to the laboratory in vials with stream water, then measured and individually isolated in glass vials with distilled water. They were exposed to artificial light and temperature to induce cercarial emergence. The most actively emerging cercariae were processed by differential staining and silver nitrate impregnation methods. Negative snails were subsequently dissected. Approximately 700 snails were collected. Snail total lengths ranged from 1.2 to 3.3 cm. The prevalence rate was 15.76% although 53.76% of the snails were found infected in one of the sites. Infected snails were infected with rediae and pleurolophocercous cercariae. Cercarial morphology and chaetotaxy were consistent with those of the family Heterophyidae mostly due to the presence of median dorsal and ventral fins on the tail and the absence of CI dorsal sensory receptors.

Standard commercial education robotic platform: intermediate solution to teaching robotics

Teaching robotics to students at the beginning of their studies has become a huge challenge. Simulation environments can be an effective solution to that challenge where students can interact with simulated robots and have the first contact with robotic constraints. From our previous experience with simulation environments it was possible to observe that students with lower background knowledge in robotics where able to deal with a limited number of constraints, implement a simulated robotic platform and study several sensors. The question is: after this first phase what should be the best approach? Should the student start developing their own hardware? Hardware development is a very important part of an engineer's education but it can also be a difficult phase that could lead to discouragement and loss of motivation in some students. Considering the previous constraints and first year engineering students’ high abandonment rate it is important to develop teaching strategies to deal with this problem in a feasible way. The solution that we propose is the integration of a low-cost standard robotic platform WowWee Rovio as an intermediate solution between the simulation phase and the stage where the students can develop their own robots. This approach will allow the students to keep working in robotic areas such as: cooperative behaviour, perception, navigation and data fusion. The propose approach proved to be a motivation step not only for the students but also for the teachers. Students and teachers were able to reach an agreement between the level of demand imposed by the teachers and satisfaction/motivation of the students.

Indications of carbapenem resistance evolution through heteroresistance as an intermediate stage in Acinetobacter baumannii after carbapenem administration

We describe an in vivo evolution of an antimicrobial profile from susceptibility to full-resistance to carbapenems, with heteroresistance as an intermediate stage, in an Acinetobacter baumannii strain. Heteroresistance was characterized by the growth of sub-populations within the susceptibility halo in both disk-diffusion and Etest. PCRs for the main A. baumannii carbapenemases were negative. The exact resistance mechanism, diagnostic methods and clinical relevance of heteroresistance in A. baumannii warrant further investigations. This is the first description of such phenomenon in vivo and the second report of heteroresistance to carbapenems in A. baumannii.

Melanoides tuberculata (Mollusca: Thiaridae) as an intermediate host of Centrocestus formosanus (Trematoda: Heterophyidae) in Brazil

Pleurolophocercous cercariae emerged from naturally infected Melanoides tuberculata from Minas Gerais State, Brazil, were used to perform experimental infection of laboratory-reared Poecilia reticulata. Mature metacercariae were obtained from the gills of fishes and force-fed to Mus musculus. The adult parasites which recovered from small intestines of mice were identified as Centrocestus formosanus. This is the first report of M. tuberculata as intermediate host of this heterophyid in Brazil.