Identification of selective Lyn inhibitors from the chemical databases through integrated molecular modelling approaches.

In the current study, the Asinex and ChEBI databases were virtually screened for the identification of potential Lyn protein inhibitors. Therefore, a multi-steps molecular docking study was carried out using the VSW utility tool embedded in Maestro user interface of the Schrödinger suite. On initial screening, molecules having a higher XP-docking score and binding free energy compared to Staurosporin were considered for further assessment. Based on in silico pharmacokinetic analysis and a common-feature pharmacophore mapping model developed from the Staurosporin, four molecules were proposed as promising Lyn inhibitors. The binding interactions of all proposed Lyn inhibitors revealed strong ligand efficiency in terms of energy score obtained in molecular modelling analyses. Furthermore, the dynamic behaviour of each molecule in association with the Lyn protein-bound state was assessed through an all-atoms molecular dynamics (MD) simulation study. MD simulation analyses were confirmed with notable intermolecular interactions and consistent stability for the Lyn protein-ligand complexes throughout the simulation. High negative binding free energy of identified four compounds calculated through MM-PBSA approach demonstrated a strong binding affinity towards the Lyn protein. Hence, the proposed compounds might be taken forward as potential next-generation Lyn kinase inhibitors for managing numerous Lyn associated diseases or health complications after experimental validation.

Spiral formation at the microscale by µ-pyro-electrospinning.

Spiral shapes occur frequently in nature as in the case of snail shells or the cochlea - the auditory portion of the inner ear. They also inspire many technological devices that take advantage of this geometry. Here we show that µ-pyro-electrospinning is able to control whipping instabilities in order to form spiralling fibres (down to 300 nm thick) directly on a support with true microscale regularity. The results show that polymer concentration plays a key role in producing reliable and long spirals. We investigate the cell response to these spiral templates that, thanks to their true regularity, would be useful for developing innovative cochlea regeneration scaffolds.

Observation of standing waves of electron-hole sound in a photoexcited semiconductor.

Three-dimensional multicomponent plasmas composed of species with very different masses support a new branch of charge-density fluctuations known as acoustic plasmons. Here, we report on an ultrafast optical method to generate and probe coherent states of acoustic plasmons in a slab of GaAs, which relies on strong photoexcitation to create a large population of light electrons and heavy holes. Consistent with the random-phase-approximation theory, the data reveal standing plasma waves confined to these slabs, similar to those of conventional sound but with associated velocities that are significantly larger.

Spontaneous assembly of carbon-based chains in polymer matrixes through surface charge templates.

Stable chains of carbon-based nanoparticles were formed directly in polymer matrixes through an electrode-free approach. Spontaneous surface charges were generated pyroelectrically onto functionalized ferroelectric crystals, enabling the formation of electric field gradients that triggered the dipole-dipole interactions responsible for the alignment of the particles, while embedded in the polymer solution. The phenomenon is similar to the dielectrophoretic alignment of carbon nanotubes reported in the literature. However, here the electric fields are generated spontaneously by a simple heat treatment that, simultaneously, aligns the particles and provides the energy necessary for curing the host polymer. The result is a polymer sheet reinforced with well-aligned chains of carbon-based particles, avoiding the invasive implementation of appropriate electrodes and circuits. Because polymers with anisotropic features are of great interest for enhancing the thermal and/or the electrical conductivity, the electrode-free nature of this technique would improve the scaling down and the versatility of those interconnections that find applications in many fields, such as electronics, sensors, and biomedicine. Theoretical simulations of the interactions between the particles and the charge templates were implemented and appear in good agreement with the experimental results. The chain formation was characterized by controlling different parameters, including surface charge configuration, particle concentration, and polymer viscosity, thus demonstrating the reliability of the technique. Moreover, micro-Raman spectroscopy and scanning electron microscopy were used for a thorough inspection of the assembled chains.

Improving fatigue damage resistance of alumina through surface grading.

Porcelain-veneered alumina crown restorations often fail from bulk fracture resulting from radial cracks that initiate at the cementation surface with repeated flexure of the stiffer crown layers on the soft dentin support. We hypothesized that bulk fracture may be substantially mitigated by grading the elastic modulus at the crown surfaces. In this study, we fabricated graded structures by infiltrating glass into dense alumina plates, resulting in a diminished modulus at the surface layers. The plates were then bonded to polycarbonate substrates and subjected to fatigue loading in water. Tests were terminated when fracture occurred at the cementation tensile surface or at the fatigue endurance limit (1 million cycles). Infiltrated specimens showed a significant increase in fatigue fracture loads over non-infiltrated controls. Our results indicate that controlled elastic gradients at the surface could be highly beneficial in the design of fracture-resistant alumina crowns.

Veneer vs. core failure in adhesively bonded all-ceramic crown layers.

Joining a brittle veneer to a strong ceramic core with an adhesive offers potential benefits over current fabrication methods for all-ceramic crowns. We tested the hypothesis that such joining can withstand subsurface radial cracking in the veneer, from enhanced flexure in occlusal loading, as well as in the core. Critical conditions to initiate fractures were investigated in model crown-like layer structures consisting of glass veneers epoxy-joined onto alumina or zirconia cores, all bonded to a dentin-like polymer base. The results showed a competition between critical loads for radial crack initiation in the veneers and cores. Core radial cracking was relatively independent of adhesive thickness. Zirconia cores were much less susceptible to fracture than alumina, attributable to a relatively high strength and low modulus. Veneer cracking did depend on adhesive thickness. However, no significant differences in critical loads for veneer cracking were observed for specimens containing alumina or zirconia cores.

In vitro assessment of the efficacy of thermal therapy in human benign prostatic hyperplasia.

The successful management of BPH with minimally invasive thermal therapies requires a firm understanding of the temperature-time relationship for tissue destruction. In order to accomplish this objective, the present in vitro study assesses the cellular viability of human BPH tissue subjected to an experimental matrix of different temperature-time combinations. Hyperplastic prostate tissue was obtained from 10 radical prostatectomy specimens resected for adenocarcinoma. A portion of hyperplastic tissue from the lateral lobe of each prostate was sectioned into multiple 1 mm thick tissue strips, placed on a coverslip and thermally treated on a controlled temperature copper block with various temperatures (45-70 degrees C) for various times (1-60 min). After heat treatment, the tissue slices were cultured for 72 h and viability was assessed using two independent assays: histology and dye uptake for stromal tissue and using histology alone for the glandular tissue. The hyperplastic human prostate tissue showed a progressive histological increase in irreversible injury with increasing temperature-time severity. The dye uptake and histology results for stromal viability were similar for all temperature-time combinations. In vitro thermal injury showed 85-90% stromal destruction (raw data) of human BPH for temperature-time combinations of 45 degrees C for 60 min, 50 degrees C for 30 min, 55 degrees C for 5 min, 60 degrees C for 2 min and 70 degrees C for 1 min. Apoptosis was also identified in the control and milder treated tissues with the degree of glandular apoptosis (about 20%) more than that seen in the stromal regions (< 5%). The Arrhenius model of injury was fitted to the data for conditions leading to a 90% drop in viability (normalized to control) obtained for stromal tissue. The activation energies (E) were 40.1 and 38.4 kcal/mole for the dye uptake study and histology, respectively, and the corresponding frequency factors (A) were 1.1 x 10(24) and 7.78 x 10(22)/s. This study presents the first temperature-time versus tissue destruction relation for human BPH tissue. Moreover, it supports the concept that higher temperatures can be used for shorter durations to induce tissue injury comparable with the current clinically recommended lower temperature-longer time treatments (i.e. 45 degrees C for 60 min) for transurethral microwave thermotherapy of the prostate.

In vitro thermal therapy of AT-1 Dunning prostate tumours.

To advance the utility of prostate thermal therapy, this study investigated the thermal thresholds (temperature-time) for prostate tissue destruction in vitro. The AT-1 Dunning prostate tumour model was chosen for the study. Three hundred micron thick sections were subjected to controlled temperature-time heating, which ranged from low (40 degrees C, 15 min) to high thermal exposures (70 degrees C, 2 min) (n = 6). After subsequent tissue culture at 37 degrees C, the sections were evaluated for tissue injury at 3, 24 and 72 h by two independent methods: histology and dye uptake. A graded increase in injury was identified between the low and high thermal exposures. Maximum histologic injury occurred above 70 degrees C, 1 min with >95% of the tissue area undergoing significant cell injury and coagulative necrosis. The control and 40 degrees C, 15 min sections showed histologic evidence of apoptosis following 24 and 72 h in culture. Similar signs of apoptosis were minimal or absent at higher thermal histories. Vital-dye uptake quantitatively confirmed complete cell death after 70 degrees C, 2 min. Using the dye data, Arrhenius analysis showed an apparent breakpoint at 50 degrees C, with activation energies of 135.8 kcal/mole below and 4.7 kcal/mole above the threshold after 3 h in culture. These results can be used as a conservative benchmark for thermal injury in the cancerous prostate. Further characterization of the response to thermal therapy in an animal model and in human tissues will be important in establishing the efficacy of the procedure

Sublethal temperature stress in juvenile Labeo rohita (Ham-Buch.) and Rita rita (Ham.): some physiological changes.

Juveniles of fish L. rohita and R. rita subjected to a rapid (5 min) sublethal temperature increase from 28 to 35 degrees C showed significant increase in cortisol and decrease in interrenal ascorbic acid. Hypercholesterolemia, hyperglycemia and hyperlactemia were also evident accompanied by increased blood haemoglobin and haematocrit and stable protein levels. Compensatory responses were initiated within 72 hr in both the fishes. R. rita recovered more quickly indicating it to be more resistant to the heat stress than L. rohita. Hence fishes subjected to sublethal temperature stress should be given a metabolic recovery period of 72 hr prior to further stress being applied.

Hereditary gingival fibromatosis and growth retardation.

OBJECTIVE: To describe two patients with hereditary gingival fibromatosis (HGF) and growth hormone deficiency and to review the literature on HGF and related endocrine abnormalities. METHODS: We present case reports of two patients (first cousins)-an 8-year-old girl and a 13-year-old boy-with an existing diagnosis of HGF, who were assessed because of presumed growth failure. Both patients underwent growth hormone stimulation testing and more in-depth endocrine evaluation, including measurement of morning cortisol, adrenocorticotropic hormone (ACTH), and prolactin levels as well as thyroid function tests. An ACTH stimulation test was also performed. Radiologic evaluation included assessment of bone age and magnetic resonance imaging of the brain. RESULTS: In addition to HGF, both patients had short stature, subnormal growth velocity, and delayed bone age but no abnormalities on magnetic resonance imaging of the brain. Serum prolactin levels and results of thyroid function tests were normal. Subnormal growth hormone response was noted during hypoglycemia and pharmacologic stimuli with clonidine and levodopa. The female patient, who also had recurrent hypoglycemic episodes, had a suboptimal cortisol and ACTH response during hypoglycemia. On the ACTH stimulation test, she showed an inadequate cortisol response at 30 minutes but a normal response at 60 minutes. The male patient had normal morning cortisol and ACTH levels plus a normal response to ACTH stimulation. Both patients are responding well to treatment with growth hormone. The girl is also receiving cortisol replacement and has had no further episodes of hypoglycemia. CONCLUSION: Although HGF has been described as an isolated finding, it can occur as part of a syndrome, including infrequent endocrine abnormalities such as growth hormone insufficiency. The cause of the growth hormone deficiency remains unclear in these two patients. We believe that patients with HGF should be monitored carefully for a prolonged period for growth as well as other endocrine abnormalities.

Evaluation of thermal therapy in a prostate cancer model using a wet electrode radiofrequency probe.

PURPOSE: To determine the temperature-time threshold of local cell death in vivo for thermal therapy in a prostate cancer animal model and to use this value as a benchmark to quantify global tissue injury. MATERIALS AND METHODS: Two studies were designed in the Dunning AT-1 rat prostate tumor hind limb model. For both studies, a wet electrode radiofrequency (RF) probe was used to deliver 40 W of energy for 18 to 62 seconds after a 30-second infusion of hypertonic saline/Hypaque through the RF antenna. Thermal history measurements were obtained in tumors from at least two Fluoroptic probes placed radially 5 mm from the axis of a RF probe and 10 mm below the surface of the tissue. In study 1, the thermal history required for irreversible cell injury was experimentally determined by comparing the predicted injury accumulation (omega) with cell viability at the fluoroptic probe locations using an in vivo-in vitro assay. The omega value was calculated from the measured thermal histories using an Arrhenius damage model. In study 2, RF energy was applied for 40 seconds in all cases. At 1, 3, and 7 days after thermal therapy, triphenyltetrazolium chloride dye (TTC) and histologic analyses were performed to assess global tissue injury within a 5-mm radius from the axis of the RF probe. RESULTS: Study 1 showed that cell survival dropped to 0 for 0.42 < omega < 0.7. This result was the basis for selection of 40 seconds of RF thermal therapy in study 2, which yielded omegaave = 0.5 in the tissue 5 mm from the probe axis. Both TTC and histology analysis showed that sham-treated tissue was not irreversibly injured. However, there was an inherent heterogeneity present in the tumor that accounted for as much as 15% necrosis in control or sham-treated tissue. In contrast, at 1, 3, and 7 days after therapy, significantly less enzyme activity was observed by TCC in thermally treated tissue compared with sham-treated tissue (35 v 85%; P < 0.001). Histologic analysis of thermally treated tissues revealed a gradual increase in the percent of coagulative necrosis (47%-70%) with a concomitant decrease in the percentage of shocked cells (53%-28%). At day 7, <3% viability was observed in treated tumors compared with 90% viability in sham-treated tissue. CONCLUSION: The threshold of cellular injury in vivo corresponded to omega > 0.7 (> or =48 degrees C for 40 seconds). Global tissue injury could be conservatively predicted on the basis of local thermal histories during therapy.

Castleman's disease: atypical manifestation in an 11-year-old girl.

Castleman's disease (angiofollicular lymphoid hyperplasia) is a rare lymphoproliferative disorder that can be found in both nodal and extranodal sites. It is classified histologically as the more common hyaline vascular variant, a plasma cell variant, or a mixed form. The hyaline vascular variant is typically characterized by a benign clinical course with no constitutional symptoms other than localized pressure from the mass. We report an atypical case of the hyaline vascular variant with constitutional symptoms that have been clinically associated with the aggressive plasma cell variant. Diagnosis was confirmed histopathologically after surgical resection, which was curative and resulted in resolution of all symptoms. This case broadens our understanding of Castleman's disease as a part of the spectrum of lymphoproliferative and inflammatory diseases. Furthermore, it supports recent studies suggesting that systemic pathogenicity is related to associated cytokine dysregulation and highlights the need to include Castleman's disease in the differential diagnosis of pediatric lymphoproliferative disorders.

Supraphysiological thermal injury in Dunning AT-1 prostate tumor cells.

To investigate the potential application of thermal therapy in the treatment of prostate cancer, the effects of supraphysiological temperatures (40-70 degrees C) for clinically relevant time periods (approximately 15 minutes) were experimentally studied on attached Dunning AT-1 rat prostate cancer cells using multiple assays. The membrane and reproductive machinery were the targets of injury selected for this study. In order to assess membrane injury, the leakage of calcein was measured dynamically, and the uptake of PI was measured postheating (1-3 hours). Clonogenicity was used as a measure of injury to the reproductive machinery 7 days post-injury after comparable thermal insults. Experimental results from all three assays show a broad trend of increasing injury with an increase in temperature and time of insult. Membrane injury, as measured by the fluorescent dye assays, does not correlate with clonogenic survival for many of the thermal histories investigated. In particular, the calcein assay at temperatures of < or = 40 degrees C led to measurable injury accumulation (dye leakage), which was considered sublethal, as shown by significant survival for comparable insult in the clonogenic assay. Additionally, the PI uptake assay used to measure injury post-thermal insult shows that membrane injury continues to accumulate after thermal insult at temperatures > or = 50 degrees C and may not always correlate with clonogenicity at hyperthermic temperatures such as 45 degrees C. Last, although the clonogenic assay yields the most accurate cell survival data, it is difficult to acquire these data at temperatures > or = 50 degrees C because the thermal transients in the experimental setup are significant as compared to the time scale of the experiment. To improve prediction and understanding of thermal injury in this prostate cancer cell line, a first-order rate process model of injury accumulation (the Arrhenius model) was fit to the experimental results. The activation energy (E) obtained using the Arrhenius model for an injury criterion of 30 percent for all three assays revealed that the mechanism of thermal injury measured is likely different for each of the three assays: clonogenics (526.39 kJ/mole), PI (244.8 kJ/mole), and calcein (81.33 kJ/mole). Moreover, the sensitivity of the rate of injury accumulation (d omega/dt) to temperature was highest for the clonogenic assay, lowest for calcein leakage, and intermediate for PI uptake, indicating the strong influence of E value on d omega/dt. Since the clonogenic assay is linked to the ultimate survival of the cell and accounts for all lethal mechanisms of cellular injury, the E and A values obtained from clonogenic study are the best values to apply to predict thermal injury in cells. For higher temperatures (> or = 50 degrees C) indicative of thermal therapies, the results of PI uptake can be used as a conservative estimate of cell death (underprediction). This is useful until better experimental protocols are available to account for thermal transients at high temperature to assess clonogenic ability. These results provide further insights into the mechanisms of thermal injury in single cell systems and may be useful for designing optimal protocols for clinical thermal therapy.

Pitfalls of conventional human chorionic gonadotropin stimulation test to detect hormonally functional cryptorchid testes in midchildhood.

OBJECTIVE: To report two cases misdiagnosed as bilateral anorchism in midchildhood on the basis of multiple conventional human chorionic gonadotropin (HCG) stimulation tests and sonograms of the abdomen and pelvis. METHODS: In two young male patients with cryptorchidism who were considered to have anorchism, we describe the findings on clinical examination, the testosterone levels before and after standard HCG stimulation testing, and sonographic findings during the midchildhood period. In both cases, as the children approached puberty the diagnosis was found to be incorrect. RESULTS: Two boys, 8 and 91/2 years old, were seen in consultation in our Pediatric Endocrine Clinic with a presumed diagnosis of anorchism. In the first case, multiple conventional HCG stimulation tests were done. In the second case, a single stimulation test was performed during routine follow-up assessments. In both cases, testosterone levels before and after HCG stimulation were consistent with the diagnosis of absent functional testicular tissue. Sonograms of the abdomen and pelvis also failed to detect the testicles. Both patients were ultimately noted to be pubertal (at 14 1/2 and >13 1/2 years, respectively) and to have early pubertal testosterone levels. A testicle was detected in one patient by abdominal computed tomographic scan and in the other by palpation of the inguinal canal. CONCLUSION: Conventional dosing and duration of the HCG stimulation test, as widely recommended in standard textbooks and in articles in the medical literature, may not elicit positive HCG-induced testosterone responses during midchildhood for detection of functional testicular tissue. During the midchildhood period, which is characterized by low gonadotropin, low sex steroid production, and a highly sensitive hypothalamic-pituitary-gonadal axis to feedback inhibition, a prolonged HCG stimulation test-perhaps of 4 to 6 weeks' duration-may be necessary. In addition, other investigational modalities may need to be used to detect the presence of functional testicular tissue during this developmental period.

Midline posterior cervical cystic hygroma.

Cystic hygromas are among the most common congenital neck masses. They have a predilection for the left posterior triangle and manifest early in life. Although various locations of cystic hygromas are found in the literature, we believe our case of a 9-month-old girl represents the first reported occurrence of a posterior cervical midline cystic hygroma.

Response of a liver tissue slab to a hyperosmotic sucrose boundary condition: microscale cellular and vascular level effects.

Transport of a non-permeating CPA in liver tissue was studied by experimental and theoretical techniques. The system consisted of a 20 mm x 15 mm x 500 microns (thick) slab of liver tissue which was exposed to culture media and hyperosmotic sucrose (0.3 or 0.6 M) at the boundary. The volumetric changes of cell and vascular spaces within the tissue slab at 125 microns from one of the symmetric boundaries was studied by slam freezing followed by freeze substitution microscopy. The experimental data was then theoretically investigated using two models; one based on an effective diffusion coefficient for sucrose, and another which incorporated the convective flux of water out of the cells (and the tissue) while sucrose diffuses in. We estimate the effective diffusion of sucrose as 16-33% of the actual diffusivity of sucrose in bulk water. The role of convection of water out of the tissue is against the flow of sucrose and appears to be important in reducing the effective diffusivity of the sucrose. The role of vascular compliance, porosity and tortuosity are also discussed with respect to our results.

Management of multiple-antibody-mediated hyperthyroidism in children with Down's syndrome.

During a period of 7 years at our institution, four girls and one boy with Down's syndrome, ages 9 to 16 years, were examined and treated for hyperthyroidism. Two patients had Graves' disease and they responded to propylthiouracil (PTU) with a predictable clinical course resulting in remission within 4 years. The remaining three patients included in this report had hyperthyroid profiles similar to those of the two with Graves' disease except for their antibody panels. These patients, in addition to the elevated thyroid-stimulating immunoglobulin (TSI) level observed in Graves' disease, also had significantly elevated antimicrosomal antibody (AMA) and antithyroglobulin antibody (ATGA) at the time of diagnosis. Elevated TSI level was again present in two patients who had a recurrence of hyperthyroidism after PTU therapy was discontinued. Treatment of these three patients was best done with the continuation of PTU therapy at a lower dose and the addition of thyroxine as soon as mild hypothyroidism developed. Treatment with PTU and thyroxine was continued until the TSI level was no longer elevated. Levels of AMA and ATGA remained elevated long after the TSI level became normal. All three patients eventually had hypothyroidism and continue to require thyroxine replacement.

Neurologic syndrome with antiphospholipid antibodies : a case report.

We report a case of probable Antiphospholipid Antibody syndrome presenting with neurologic manifestations and high levels of IgG aCL antibodies.