IRC +10 216 in 3-D: morphology of a TP-AGB star envelope.

During their late pulsating phase, AGB stars expel most of their mass in the form of massive dusty envelopes, an event that largely controls the composition of interstellar matter. The envelopes, however, are distant and opaque to visible and NIR radiation: their structure remains poorly known and the mass-loss process poorly understood. Millimeter-wave interferometry, which combines the advantages of longer wavelength, high angular resolution and very high spectral resolution is the optimal investigative tool for this purpose. Mm waves pass through dust with almost no attenuation. Their spectrum is rich in molecular lines and hosts the fundamental lines of the ubiquitous CO molecule, allowing a tomographic reconstruction of the envelope structure. The circumstellar envelope IRC +10 216 and its central star, the C-rich TP-AGB star closest to the Sun, are the best objects for such an investigation. Two years ago, we reported the first detailed study of the CO(2-1) line emission in that envelope, made with the IRAM 30-m telescope. It revealed a series of dense gas shells, expanding at a uniform radial velocity. The limited resolution of the telescope (HPBW 11″) did not allow us to resolve the shell structure. We now report much higher angular resolution observations of CO(2-1), CO(1-0), CN(2-1) and C4H(24-23) made with the SMA, PdB and ALMA interferometers (with synthesized half-power beamwidths of 3″, 1″ and 0.3″, respectively). Although the envelope appears much more intricate at high resolution than with an 11″ beam, its prevailing structure remains a pattern of thin, nearly concentric shells. The average separation between the brightest CO shells is 16″ in the outer envelope, where it appears remarkably constant. Closer to the star (< 40″), the shell pattern is denser and less regular, showing intermediary arcs. Outside the small (r < 0.3″) dust formation zone, the gas appears to expand radially at a constant velocity, 14.5 km s-1, with small turbulent motions. Based on that property, we have reconstructed the 3-D structure of the outer envelope and have derived the gas temperature and density radial profiles in the inner (r < 25″) envelope. The shell-intershell density contrast is found to be typically 3. The over-dense shells have spherical or slightly oblate shapes and typically extend over a few steradians, implying isotropic mass loss. The regular spacing of shells in the outer envelope supports the model of a binary star system with a period of 700 years and a near face-on elliptical orbit. The companion fly-by triggers enhanced episodes of mass loss near periastron. The densification of the shell pattern observed in the central part of the envelope suggests a more complex scenario for the last few thousand years.

Circumstellar chemistry of Si-C bearing molecules in the C-rich AGB star IRC+10216.

Silicon carbide together with amorphous carbon are the main components of dust grains in the atmospheres of C-rich AGB stars. Small gaseous Si-C bearing molecules (such as SiC, SiCSi, and SiC2) are efficiently formed close to the stellar photosphere. They likely condense onto dust seeds owing to their highly refractory nature at the lower temperatures (i.e., below about 2500 K) in the dust growth zone which extends a few stellar radii from the photosphere. Beyond this region, the abundances of Si-C bearing molecules are expected to decrease until they are eventually reformed in the outer shells of the circumstellar envelope, owing to the interaction between the gas and the interstellar UV radiation field. Our goal is to understand the time-dependent chemical evolution of Si-C bond carriers probed by molecular spectral line emission in the circumstellar envelope of IRC+10216 at millimeter wavelengths.

The growth of carbon chains in IRC +10216 mapped with ALMA.

Linear carbon chains are common in various types of astronomical molecular sources. Possible formation mechanisms involve both bottom-up and top-down routes. We have carried out a combined observational and modeling study of the formation of carbon chains in the C-star envelope IRC +10216, where the polymerization of acetylene and hydrogen cyanide induced by ultraviolet photons can drive the formation of linear carbon chains of increasing length. We have used ALMA to map the emission of λ 3 mm rotational lines of the hydrocarbon radicals C2H, C4H, and C6H, and the CN-containing species CN, C3N, HC3N, and HC5N with an angular resolution of ~1″. The spatial distribution of all these species is a hollow, 5-10″ wide, spherical shell located at a radius of 10-20″ from the star, with no appreciable emission close to the star. Our observations resolve the broad shell of carbon chains into thinner sub-shells which are 1-2″ wide and not fully concentric, indicating that the mass loss process has been discontinuous and not fully isotropic. The radial distributions of the species mapped reveal subtle differences: while the hydrocarbon radicals have very similar radial distributions, the CN-containing species show more diverse distributions, with HC3N appearing earlier in the expansion and the radical CN extending later than the rest of the species. The observed morphology can be rationalized by a chemical model in which the growth of polyynes is mainly produced by rapid gas-phase chemical reactions of C2H and C4H radicals with unsaturated hydrocarbons, while cyanopolyynes are mainly formed from polyynes in gas-phase reactions with CN and C3N radicals.

13-Year experience in external fixation of the pelvis: complications, reduction and removal.

PURPOSE: To evaluate the complications associated with anterior pelvic external fixation and the success of this device in maintaining reduction when used in conjunction with sacroiliac screws. METHODS: Through a retrospective clinical study at an academic Level I Trauma Center, 129 patients fit the criteria for inclusion with a mean duration of anterior pelvic external fixation of 62 days and mean follow-up of 360 days. Charts were reviewed for complications postoperatively. The symphysis diastasis, vertical displacement and posterior displacement of each hemipelvis were quantified from pelvic radiographs. RESULTS: Of the 129 patients receiving anterior pelvic external fixation, 14 (10.9 %) presented to an emergency department for problems with their anterior pelvic external fixation. Of these 14 patients, 7 (5.4 %) required readmission, all for infectious concerns necessitating IV antibiotics. 6 (4.7 %) required formal operative debridement and device removal. 13 patients (10.1 %) had superficial pin site infections successfully treated with oral antibiotics. Reduction was maintained (rated as fair, good or excellent) in all patients with radiographic follow-up (n = 74, average radiographic follow-up of 216 days) following removal of their anterior pelvic external fixation. 38 patients (30.4 %) had their anterior pelvic external fixation removed in clinic, while 87 (69.6 %) had formal removal in the operating room. CONCLUSION: While previous data suggest high complication rates in definitive anterior pelvic external fixation, we present the largest cohort of patients receiving anterior pelvic external fixation and sacroiliac screws, demonstrating a low complication rate while maintaining reduction of the pelvic ring. In addition, we found that these devices could be reliably removed in a clinic setting.

Discovery of SiCSi in IRC +10216: A missing link between gas and dust carriers of Si-C bonds.

We report the discovery in space of a disilicon species, SiCSi, from observations between 80 and 350 GHz with the IRAM 30m radio telescope. Owing to the close coordination between laboratory experiments and astrophysics, 112 lines have now been detected in the carbon-rich star CW Leo. The derived frequencies yield improved rotational and centrifugal distortion constants up to sixth order. From the line profiles and interferometric maps with the Submillimeter Array, the bulk of the SiCSi emission arises from a region of 6″ in radius. The derived abundance is comparable to that of SiC2. As expected from chemical equilibrium calculations, SiCSi and SiC2 are the most abundant species harboring a Si-C bond in the dust formation zone and certainly both play a key role in the formation of SiC dust grains.

Peripheral administration of prokineticin 2 potently reduces food intake and body weight in mice via the brainstem.

BACKGROUND AND PURPOSE: Prokineticin 2 (PK2) has recently been shown to acutely reduce food intake in rodents. We aimed to determine the CNS sites and receptors that mediate the anorectic effects of peripherally administered PK2 and its chronic effects on glucose and energy homeostasis. EXPERIMENTAL APPROACH: We investigated neuronal activation following i.p. administration of PK2 using c-Fos-like immunoreactivity (CFL-IR). The anorectic effect of PK2 was examined in mice with targeted deletion of either prokineticin receptor 1 (PKR1) or prokineticin receptor 2 (PKR2), and in wild-type mice following administration of the PKR1 antagonist, PC1. The effect of IP PK2 administration on glucose homeostasis was investigated. Finally, the effect of long-term administration of PK2 on glucose and energy homeostasis in diet-induced obese (DIO) mice was determined. KEY RESULTS: I.p. PK2 administration significantly increased CFL-IR in the dorsal motor vagal nucleus of the brainstem. The anorectic effect of PK2 was maintained in mice lacking the PKR2 but abolished in mice lacking PKR1 and in wild-type mice pre-treated with PC1. DIO mice treated chronically with PK2 had no changes in glucose levels but significantly reduced food intake and body weight compared to controls. CONCLUSIONS AND IMPLICATIONS: Together, our data suggest that the anorectic effects of peripherally administered PK2 are mediated via the brainstem and this effect requires PKR1 but not PKR2 signalling. Chronic administration of PK2 reduces food intake and body weight in a mouse model of human obesity, suggesting that PKR1-selective agonists have potential to be novel therapeutics for the treatment of obesity.

Birth of a relativistic outflow in the unusual γ-ray transient Swift J164449.3+573451.

Active galactic nuclei, which are powered by long-term accretion onto central supermassive black holes, produce relativistic jets with lifetimes of at least one million years, and the observation of the birth of such a jet is therefore unlikely. Transient accretion onto a supermassive black hole, for example through the tidal disruption of a stray star, thus offers a rare opportunity to study the birth of a relativistic jet. On 25 March 2011, an unusual transient source (Swift J164449.3+573451) was found, potentially representing such an accretion event. Here we report observations spanning centimetre to millimetre wavelengths and covering the first month of evolution of a luminous radio transient associated with Swift J164449.3+573451. The radio transient coincides with the nucleus of an inactive galaxy. We conclude that we are seeing a newly formed relativistic outflow, launched by transient accretion onto a million-solar-mass black hole. A relativistic outflow is not predicted in this situation, but we show that the tidal disruption of a star naturally explains the observed high-energy properties and radio luminosity and the inferred rate of such events. The weaker beaming in the radio-frequency spectrum relative to γ-rays or X-rays suggests that radio searches may uncover similar events out to redshifts of z ≈ 6.

Cerebellin1 is a novel orexigenic peptide.

AIM: Cerebellin1 (Cbln1) is highly expressed in the hypothalamus, a region of the brain involved in appetite regulation. However, the effects of Cbn1 on food intake are not known. The present study aimed to investigate the effect of Cbln1 on appetite regulation in rats. METHODS: We determined the effect of (i) intracerebroventricular (ICV) injection of Cbln1 on food intake, behaviour and plasma pituitary hormone levels in male Wistar rats; (ii) Cbln1 on the release of hypothalamic neuropeptides known to modulate food intake from hypothalamic explants and (iii) fasting on hypothalamic Cbln1 mRNA expression. RESULTS: (i) ICV administration of Cbln1 significantly increased food intake in rats and caused no adverse behaviours. ICV administration of Cbln1 significantly reduced plasma thyroid stimulating hormone (TSH) levels 10 min postinjection in rats. (ii) Cbln1 significantly increased the release of neuropeptide Y (NPY) from hypothalamic explants. (iii) Cbln1 mRNA expression levels were increased in the ventromedial nucleus of the hypothalamus in fasted rats. CONCLUSIONS: These data suggest that Cbln1 is a novel orexigenic peptide, which may mediate its effects via hypothalamic NPY.

Developmentally spliced PKCbetaII provides a possible link between mTORC2 and Akt kinase to regulate 3T3-L1 adipocyte insulin-stimulated glucose transport.

Functional adipocyte glucose disposal is a key component of global glucose homeostasis. PKCbetaII is involved in rat skeletal muscle cell ISGT. Western blot analysis and real-time PCR revealed 3T3-L1 cells developmentally regulated PKCbeta splicing such that PKCbetaI was downregulated and PKCbetaII was upregulated during the course of differentiation. An initial glucose uptake screen using PKC inhibitor LY379196 pointed to a PKC isozyme other than PKCzeta mediating 3T3-L1 adipocyte ISGT. Subsequent use of PKCbetaII inhibitor CGP53353 pointed to a role for PKCbetaII in ISGT. Western blot analysis showed that CGP53353 specifically inhibited phosphorylation of PKCbetaII Serine 660. Subcellular fractionation and immunofluorescence demonstrated that PKCbetaII regulates GLUT4 translocation. Further Western blot, immunofluorescence and co-immunoprecipitation analysis reveal that PKCbetaII inhibition does not affect mTORC2 activity yet abrogates phosphorylation of Akt Serine 473. PKCbetaII regulates GLUT4 translocation by regulating Akt phosphorylation and thus activity.

Functional involvement of protein kinase C-betaII and its substrate, myristoylated alanine-rich C-kinase substrate (MARCKS), in insulin-stimulated glucose transport in L6 rat skeletal muscle cells.

AIMS/HYPOTHESIS: Insulin stimulates phosphorylation cascades, including phosphatidylinositol-3-kinase (PI3K), phosphatidylinositol-dependent kinase (PDK1), Akt, and protein kinase C (PKC). Myristoylated alanine-rich C-kinase substrate (MARCKS), a PKCbetaII substrate, could link the effects of insulin to insulin-stimulated glucose transport (ISGT) via phosphorylation of its effector domain since MARCKS has a role in cytoskeletal rearrangements. METHODS: We examined phosphoPKCbetaII after insulin treatment of L6 myocytes, and cytosolic and membrane phosphoMARCKS, MARCKS and phospholipase D1 in cells pretreated with LY294002 (PI3K inhibitor), CG53353 (PKCbetaII inhibitor) or W13 (calmodulin inhibitor), PI3K, PKCbetaII and calmodulin inhibitors, respectively, before insulin treatment, using western blots. ISGT was examined after cells had been treated with inhibitors, small inhibitory RNA (siRNA) for MARCKS, or transfection with MARCKS mutated at a PKC site. MARCKS, PKCbetaII, GLUT4 and insulin receptor were immunoblotted in subcellular fractions with F-actin antibody immunoprecipitates to demonstrate changes following insulin treatment. GLUT4 membrane insertion was followed after insulin with or without CG53353. RESULTS: Insulin increased phosphoPKCbetaII(Ser660 and Thr641); LY294002 blocked this, indicating its activation by PI3K. Insulin treatment increased cytosolic phosphoMARCKS, decreased membrane MARCKS and increased membrane phospholipase D1 (PLD1), a protein regulating glucose transporter vesicle fusion resulted. PhosphoMARCKS was attenuated by CG53353 or MARCKS siRNA. MARCKS siRNA blocked ISGT. Association of PKCbetaII and GLUT4 with membrane F-actin was enhanced by insulin, as was that of cytosolic and membrane MARCKS. ISGT was attenuated in myocytes transfected with mutated MARCKS (Ser152Ala), whereas overproduction of wild-type MARCKS enhanced ISGT. CG53353 blocked insertion of GLUT4 into membranes of insulin treated cells. CONCLUSIONS/INTERPRETATION: The results suggest that PKCbetaII is involved in mediating downstream steps of ISGT through MARCKS phosphorylation and cytoskeletal remodelling.

The thyroid hormone derivative 3-iodothyronamine increases food intake in rodents.

BACKGROUND: The thyroid hormone derivative 3-iodothyronamine (T(1)AM), an endogenous biogenic amine, is a potent agonist of the G protein-coupled trace amine-associated receptor 1 (TAAR1). T(1)AM is present in rat brain, and TAAR1 is expressed in hypothalamic nuclei associated with the regulation of energy homeostasis. AIM: The aim of this study was to determine the effects of T(1)AM on food intake in rodents. METHODS: We determined the effect of (i) intraperitoneal (i.p.) administration of T(1)AM on food intake, oxygen consumption (VO(2)) and locomotor activity in mice; (ii) intracerebroventricular (ICV) injection of T(1)AM on food intake in male rats; (iii) c-fos expression following ventricular administration of T(1)AM in male rats; and (iv) direct injection of T(1)AM into the arcuate nucleus (ARC) of male rats on food intake. RESULTS: (i) T(1)AM (4 nmol/kg) significantly increased food intake following i.p. injection in mice but had no effect on VO(2) or locomotor activity. (ii) ICV administration of T(1)AM (1.2 nmol/kg) significantly increased food intake in male rats. (iii) Intraventricular administration of T(1)AM significantly increased c-fos expression in the ARC of male rats. (iv) Direct administration of T(1)AM (0.12, 0.4 and 1.2 nmol/kg) into the ARC of male rats significantly increased food intake. CONCLUSION: These data suggest that T(1)AM is an orexigenic factor that may act through the ARC to increase food intake in rodents.

Comparative development and evaluation of topical gel and cream formulations of psoralen.

The aim of the present investigation is to develop topical gel and cream formulations of psoralen for enhancing its transport through the skin, with the goal to shorten the delay between drug application and UVA irradiation. In our first studies, oil-in-water (O/W) creams of psoralen (0.05% concentration) were prepared using Apifil (PEG-8 Beeswax) and Plurol Stearique WL 1009 as emulsifying agents and aqueous cream (British Pharmaceutical Codex) as the cream base material. In our second studies, hydroalcoholic transparent gel formulations of this drug in a 0.05% concentration were prepared using hydroxypropylcellulose (HPC) as the gelling agent. The physicochemical compatibility between psoralen and formulation excipients used in the cream and gel formulations was confirmed by using differential scanning calorimetry and Fourier transform infrared spectroscopy. All prepared cream and gel formulations were evaluated for drug content uniformity, viscosity, pH, stability, and limpidity. The release of psoralen from all formulations via dialysis through a cellulose membrane into phosphate buffer pH 6.8 at 37°C was studied. The penetration enhancing effect of menthol (0-12.5%, w/w) on the percutaneous flux of psoralen through excised rat epidermis from gel and cream formulations was also investigated. The release profile of psoralen from gel formulations was higher than that from cream formulations. The percutaneous flux and enhancement ratio of psoralen across rat epidermis was significantly enhanced by the addition of menthol in both gel and cream formulations as compared to gel and cream formulations prepared without menthol (p < 0.05).

Symptomatic refractures after vertebroplasty in patients with steroid-induced osteoporosis.

BACKGROUND AND PURPOSE: Refracture after percutaneous vertebroplasty in patients receiving oral glucocorticoid therapy has caused some patients and referring physicians to have negative perceptions concerning the efficacy of the initial vertebroplasty treatment. The purpose of this study was to analyze symptomatic refractures after vertebroplasty in patients on oral steroid therapy. We hypothesized that the higher refracture rate of patients on oral glucocorticoid therapy after percutaneous vertebroplasty is due not to an inadequacy of the procedure but rather to a naturally higher predisposition of these patients to refracture compared with patients with primary osteoporosis. METHODS: A retrospective analysis was performed on all osteoporosis patients having initial vertebroplasty from August 1999 to August 2003. The follow-up period was limited to 1 year after initial vertebroplasty session, with the last follow-up date ending in August 2004. Data were collected on 387 osteoporosis patients. RESULTS: Of the patients with primary osteoporosis, 20.6% patients refractured whereas 37.8% of the patients with steroid-induced osteoporosis had symptomatic refractures within 1 year of initial vertebroplasty. Relative risk of refracture within 1 year for the patients with steroid-induced osteoporosis was 1.84 compared with the patients with primary osteoporosis. In addition, the patients with steroid-induced osteoporosis were more likely to refracture after their second treatment session (within 1 year of initial vertebroplasty) than those with primary osteoporosis. CONCLUSION: Patients presenting on oral steroid therapy at their initial vertebroplasty are almost twice more likely to have symptomatic refractures than primary osteoporosis patients within 1 year of initial vertebroplasty.

Fatal fat embolism after vertebroplasty: identification of the high-risk patient.

We report a rare complication of autopsy-proven fat and bone marrow embolization following percutaneous vertebroplasty in a patient who had no evidence of cement leakage. Cement injection was done during one patient encounter, covering 3 vertebral levels by using a unipedicular approach. Patients may have complications even without polymethylmethacrylate leakage.

Accurate axillary nodal staging can be achieved after neoadjuvant therapy for locally advanced breast cancer.

Lymph node status remains the most important prognostic indicator for breast cancer. Recent reports have established that the accuracy of assessing lymph node status is proportional to the number of nodes dissected. The accuracy of axillary staging following neoadjuvant chemotherapy has been cited as a technical concern due to limited node retrieval. The current study attempts to evaluate the ability to perform sentinel node biopsy (SNB) and formal axillary node dissection (AND) following neoadjuvant chemotherapy and to compare these results with non-neoadjuvant patients. One hundred sixteen consecutive patients undergoing SNB with simultaneous AND were retrospectively reviewed. Forty-two of these patients were treated with neoadjuvant chemotherapy prior to AND. Overall success rate in performing SNB in the neoadjuvant group was 95 per cent, and no false negatives have been noted to date. The overall SNB success rate in the non-neoadjuvant group was also 95 per cent with a false negative rate of 3 per cent. After AND in each group, a mean of 21 nodes were retrieved in the neoadjuvant group and 17.9 nodes in the non-neoadjuvant group (P = 0.018). In the neoadjuvant group, there were 19 node positive patients (42%) and 21 patients (28%) in the non-neoadjuvant group (P = 0.16). The mean number of positive nodes per patient was also similar between the two groups (2.9 in the neoadjuvant group vs 1.67 in the non-neoadjuvant group, P = 0.10). Following neoadjuvant therapy, accurate evaluation of the axilla is feasible. In this study, the mean number of nodes is significantly different in favor of the neoadjuvant group, but there is no significant difference in the number of node positive patients identified or in the mean number of positive nodes identified per patient. SNB is technically feasible with accuracy similar to that seen in patients with no history of neoadjuvant therapy. Neoadjuvant chemotherapy extends the use of breast-conserving therapy without sacrificing the ability to accurately stage the axilla either by use of standard axillary dissection or SNB.

Optical coherence tomographic elastography technique for measuring deformation and strain of atherosclerotic tissues.

OBJECTIVES: To evaluate optical coherence tomographic elastography as a method for assessing the elastic properties of atherosclerotic plaque and the parameters that influence interpretation. METHODS: Phantoms and aorta were examined in vitro to quantify speckle modulation and measure the displacement and strain maps. A correlation method was used as a speckle tracking technique for measuring axial and lateral displacement vectors and calculation of strain maps. The influence of correlation kernel size on accuracy of the method was evaluated. RESULTS: In terms of a percentage error between calculated and measured displacements, the best results for phantoms were obtained with a 41 x 41 kernel (1.88% error). For both phantom and aorta images, it was found that, with the increasing size of cross correlation kernel, the axial and lateral displacement maps are less noisy and the displacement vectors are more clearly defined. However, the large kernels tend to average out the differences in displacements of small particles in phantoms and decrease the ability of speckle tracking to make microstructural assessments. Therefore, it is important to select kernel size carefully, based on the image features. CONCLUSIONS: Optical tomographic elastography can be used to assess the microstructural properties of atherosclerotic tissue at micrometre scale resolution, but preselected analysis criteria must be understood in a critical interpretation of the results.

Neoadjuvant chemotherapy for locally advanced breast cancer results in alterations in preoperative tumor marker status.

Neoadjuvant therapy followed by breast-conserving surgery has become an acceptable option for patients with locally advanced breast cancer. Although a distinct survival benefit has not been demonstrated using this approach, several questions have been raised following such therapy including its effects on receptor status and tumor markers. The current study retrospectively reviews estrogen receptor (ER), progesterone receptor (PR), and HER2-neu status in 55 consecutive patients treated by neoadjuvant chemotherapy. Preoperative and postoperative tumor markers were available for 43 of the 55 patients (78%). The pathologic complete tumor response rate (pCR) for this group was 19 per cent (8/43). Of those patients who did not achieve a pCR (n = 35), a change in tumor markers was seen in 25.7 per cent (9/35) of patients. When compared to a control group not undergoing neoadjuvant therapy, a significantly higher percent change in marker expression was noted in the neoadjuvant group (25.7% vs 5.9%, P = 0.046). ER, PR, and HER2-neu status remain important prognostic indicators for breast cancer. Tumor markers are useful in planning adjuvant therapy regimens. In this review, nearly 19 per cent of patients achieved a pCR. In patients not achieving a pCR, one in four patients had at least one change in tumor marker status. This study demonstrates the importance of establishing receptor and marker status prior to neoadjuvant therapy, as many patients will achieve a pCR and make tumor analysis impossible. Postoperative marker studies should be performed given the possibility of a change in status. The clinical relevance of this data will require further long-term follow-up. Until such data becomes available, caution should be considered when basing adjuvant therapy regimens on preoperative tumor marker studies alone.

A new approach for assessing early osteoarthritis in the rat.

Several animal models have been developed to investigate osteoarthritis and potential disease-modifying therapeutics. However, early disease data from these models are limited by the resolution of current imaging modalities. In this in-vitro study, an optical coherence tomography (OCT) system with an axial resolution of 15 micro m was used to track sequential changes in osteoarthritic rat knees. Osteoarthritis was induced via transection of the medial collateral ligament and an artificial full thickness meniscal tear. Imaging occurred at one, two, and three weeks after surgery. OCT successfully detected early signs of osteoarthritic change, including alteration of the cartilage surface and disruption of the bone-cartilage interface. This study demonstrates that OCT, along with the induction of mechanical injury, provides an excellent model for monitoring the sequential changes of osteoarthritis.

New technology for assessing microstructural components of tendons and ligaments.

This study investigated the ability of optical coherence tomography (OCT), a recently developed technology with micron-scale resolution, to assess the microstructure of tendons and ligaments. In vitro structural- and polarization-sensitive OCT was performed on human ACL, Achilles tendon, and biceps tendon (obtained postmortem). Histology was performed on all imaged samples and compared to the corresponding OCT data. OCT images correlated well with histology. Most importantly, through polarization-sensitive OCT, the collagen in normal tissue was easily distinguished from the surrounding, supportive tissue due to the birefringent properties of organized collagen. Since the integrity of collagen is an important indicator of structural stability and pathologic state, the ability of OCT to assess collagen could be a powerful diagnostic tool in assessing tendon and ligament properties.

Dexamethasone affects cytokine-mediated adhesion of HL-60 human promyelocytic leukemia cells to cultured dermal microvascular endothelial cells.

Leukocyte endothelial adhesion (LEA) is the prelude to a complex cascade of reactions following an immunological challenge. Recently, LEA has been implicated in the molecular basis of several dermatological disorders. While the role of proinflammatory cytokines, such as interleukin-1 beta (IL-1beta) and tumor necrosis factor-alpha (TNF-alpha), in LEA has been investigated using nondermal models, limited data exist regarding their effects on LEA in dermal models. This study shows that cotreatment of cultured human dermal endothelial cells (CADMEC) with IL-1beta and TNF-alpha resulted in a marked increase in the adherence of human promyelocytic leukemia (HL-60) cells to CADMEC and an increase in expression of intercellular adhesion molecule-1 and E-selectin. Pretreatment of CADMEC with dexamethasone, a long-lasting glucocorticoid, resulted in a decrease in both HL-60 cell adhesion to CADMEC and adhesion molecule expression. Taken together, these data demonstrate that LEA may play a role in inflammatory skin conditions and in the mechanisms underlying the potential use of glucocorticoids as a treatment option.