Continuous to intermittent flows in growing granular heaps.

If a granular material is poured from above on a horizontal surface between two parallel, vertical plates, a sand heap grows in time. For small piles, the grains flow smoothly downhill, but after a critical pile size X_{c}, the flow becomes intermittent: sudden avalanches slide downhill from the apex to the base, followed by an "uphill front" that slowly climbs up, until a new downhill avalanche interrupts the process. By means of experiments, controlling the distance between the apex of the sandpile and the container feeding it from above, we show that X_{c} grows linearly with the input flux, but scales as the square root of the feeding height. We explain these facts from a phenomenological model based on the experimental observation that the flowing granular phase forms a "wedge" on top of the static one, differently from the case of stationary heaps. Moreover, we demonstrate that our controlled experiments allow to predict the value of X_{c} for the common situation in which the feeding height decreases as the pile increases in size.

Sink versus tilt penetration into shaken dry granular matter: The role of the foundation.

We study the behavior of cylindrical objects as they sink into a dry granular bed fluidized due to lateral oscillations. Somewhat unexpectedly, we have found that, within a large range of lateral shaking powers, cylinders with flat bottoms sink vertically, while those with a "foundation" consisting of a shallow ring attached to their bottom, tilt besides sinking. The latter scenario seems to dominate independently from the nature of the foundation when strong enough lateral vibrations are applied. We are able to explain the observed behavior by quasi-2D numerical simulations, which also demonstrate the influence of the intruder's aspect ratio. The vertical sink dynamics is explained with the help of a Newtonian equation of motion for the intruder. Our findings may shed light on the behavior of buildings and other manmade structures during earthquakes.

Peptidic biofunctionalization of laser patterned dental zirconia: A biochemical-topographical approach.

A dual approach employing peptidic biofunctionalization and laser micro-patterns on dental zirconia was explored, with the aim of providing a flexible tool to improve tissue integration of restorations. Direct laser interference patterning with a femtosecond Ti:Sapphire laser was employed, and two periodic grooved patterns were produced with a periodicity of 3 and 10 µm. A platform containing the cell-adhesive RGD and the osteogenic DWIVA peptides was used to functionalize the grooved surfaces. Topography and surface damage were characterized by confocal laser scanning (CLSM), scanning electron and scanning transmission electron microscopy techniques. The surface patterns exhibited a high homogeneity and subsurface damage was found in the form of nano-cracks and nano-pores, at the bottom of the valleys. Accelerated tests in water steam were carried out to assess hydrothermal degradation resistance, which slightly decreased after the laser treatment. Interestingly, the detrimental effects of the laser modification were reverted by a post-laser thermal treatment. The attachment of the molecule was verified trough fluorescence CLSM and X-ray photoelectron spectroscopy. Finally, the biological properties of the surfaces were studied in human mesenchymal stem cells. Cell adhesion, morphology, migration and differentiation were investigated. Cells on grooved surfaces displayed an elongated morphology and aligned along the patterns. On these surfaces, migration was greatly enhanced along the grooves, but also highly restricted in the perpendicular direction as compared to flat specimens. After biofunctionalization, cell number and cell area increased and well-developed cell cytoskeletons were observed. However, no effects on cell migration were found for the peptidic platform. Although some osteogenic potential was found in specimens grooved with a periodicity of 10 µm, the largest effects were observed from the biomolecule, which favored upregulation of several genes related to osteoblastic differentiation in all the surfaces.

Rolling away from the Wall into Granular Matter.

The sedimentation of solid objects into granular matter near boundaries is an almost virgin field of research. Here we describe in detail the penetration dynamics of a cylindrical object into a quasi-2D granular medium. By tracking the trajectory of the cylinder as it penetrates the granular bed, we characterize two distinct kinds of motion: its center of mass moves horizontally away from the lateral wall, and it rotates around its symmetry axis. While the repulsion is caused by the loading of force chains between the intruder and the wall, the rotation can be associated to the frictional forces between the grains and the intruder. Finally, we show the analogies between the sedimentation of twin intruders released far from any boundaries, and that of one intruder released near a vertical wall.

Outcomes of an enhanced recovery after radical cystectomy program in a prospective multicenter study: compliance and key components for success.

OBJECTIVE: To investigate the effect of an Enhanced Recovery After Surgery (ERAS) program on complications and length of stay (LOS) after radical cystectomy (RC) and to assess if the number and type of components of ERAS play a key role on the decrease of surgical morbidity. MATERIALS AND METHODS: We analyzed the data of 277 patients prospectively recruited in 11 hospitals undergoing RC initially managed according to local practice (Group I) and later within an ERAS program (Group II). Two main outcomes were defined: 90-day complications rate and LOS. As secondary variables we studied 90-day mortality, 30-day readmission and transfusion rate. RESULTS: Patients in Group II had a higher use of ERAS measures (98.6%) than those in Group I (78.2%) (p < 0.05). Patients in Groups I and II experienced similar complications (70.5% vs. 66%, p = 0.42). LOS was not different between Groups I and II (12.5 and 14 days, respectively, p = 0.59). The risk of having any complication decreases for patients having more than 15 ERAS measures adopted [RR = 0.815; 95% confidence interval (CI) 0.667-0.996; p = 0.045]. Avoidance of transfusion and nasogastric tube, prevention of ileus, early ambulation and a fast uptake of a regular diet are independently associated with the absence of complications. CONCLUSIONS: Complications and LOS after RC were not modified by the introduction of an ERAS program. We hypothesize that at least 15 measures should be applied to maximize the benefit of ERAS.

Note: "Lock-in accelerometry" to follow sink dynamics in shaken granular matter.

Understanding the penetration dynamics of intruders in granular beds is relevant not only for fundamental physics, but also for geophysical processes and construction on sediments or granular soils in areas potentially affected by earthquakes. While the penetration of intruders in two dimensional (2D) laboratory granular beds can be followed using video recording, this is useless in three dimensional (3D) beds of non-transparent materials such as common sand. Here, we propose a method to quantify the sink dynamics of an intruder into laterally shaken granular beds based on the temporal correlations between the signals from a reference accelerometer fixed to the shaken granular bed, and a probe accelerometer deployed inside the intruder. Due to its analogy with the working principle of a lock-in amplifier, we call this technique lock-in accelerometry.

Quantitative real-time reverse transcription: polymerase chain reaction of prostate-specific antigen (PSA) for detection of circulating prostatic cells in patients with clinically localized prostate cancer.

OBJECTIVE: To evaluate the clinical utility of using the real-time reverse transcriptase-polymerase chain reaction (RT-PCR) to quantify prostate-specific antigen (PSA) mRNA in peripheral blood samples from patients with prostate cancer as a predictor of extraprostatic extension of the disease and to assess any correlations with known predictive markers of this condition. METHODS: Immediately before radical prostatectomy, peripheral blood samples were taken from 42 men with clinically localized prostate cancer and analysed for PSA and 18S ribosomal (endogenous control) genes using real-time RT-PCR (with gene expression assays and the comparative CT-cycle threshold-method for quantifying). A total of 30 healthy male blood donors aged <50 y was taken as a control group. The relationships between PSA mRNA values, pathological and clinical features were analysed. PSA mRNA value, PSA level and biopsy Gleason score were then compared as predictors of extraprostatic extension. RESULTS: PSA gene expression was 3.73 times significantly higher in patients with clinically localized prostate cancer than in healthy men (P<0.05). There was no relationship between PSA real-time RT-PCR values and pathological stage pT2 or pT3 (P=0.5), and no association between PSA mRNA value and serum PSA level (P=0.9) or the Gleason score of the preoperative biopsy (P=0.9). CONCLUSION: There was no significant advantage in using the real-time RT-PCR assay of PSA mRNA before surgery to stage prostate cancer and to discriminate between organ-confined and extraprostatic extension.

The clinical utility of the prostate specific membrane antigen reverse-transcription/polymerase chain reaction to detect circulating prostate cells: an analysis in healthy men and women.

OBJECTIVE: To evaluate the overall specificity of nested reverse transcriptase-polymerase chain reaction (RT-PCR) to detect prostate-specific membrane antigen (PSM) mRNA in peripheral blood samples of healthy donors. SUBJECTS AND METHODS: Peripheral blood samples were taken from 60 healthy blood-donors (30 men and 30 women aged < 50 years) and analysed for PSM-mRNA using nested RT-PCR (in 'hot-start' conditions and confirmed using nested EcoRI restriction enzyme). Intron-spanning primer pairs specific for human PSM were deduced from the GenBank sequence (M99487) using gene software. The outer primer pair for PSM was: fwd: 1368 5'-TCACCGGGACTCATGGGTGT-3'; reverse: 1860 5'-GCCTGAAGCAATTCCAAGTCGG-3'. Inner primer pair for PSM was: fwd: 1480 5'-AAGGAAGGGTGGAGACCTAG-3'; reverse: 5-ACTGAACTCTGGGGAAGGAC-3'. The integrity of cDNAs was checked using primer pairs specific for the housekeeping gene beta-actin. The specificity and false-positive rate were calculated assuming that the underlying prostate cancer incidence was nil. RESULTS: The first PCR was negative for all samples (100% specificity; 0% false-positive rate). The nested PCR detected 23 positive samples (23/60, 38%) with an overall specificity of 62% (false positive rate, 38%). CONCLUSION: Nested RT-PCR of PSM-mRNA in peripheral blood is highly unspecific. Its clinical utility in the management of prostate cancer must be low. Further development is needed of quantitative RT-PCR, primers that identify prostatic PSM or another prostate-specific marker gene to differentiate PSM mRNA from circulating prostate cells and from non-prostatic tissues.

Prostate specific antigen density. Is there a role for this parameter when screening for prostate cancer?

The objective of this paper is to validate prostate specific antigen (PSA) density (PSAD) routine use to enhance PSA specificity in men with normal digital rectal examination and intermediate PSA values. It is a retrospective study of 235 men from a prostate cancer (PCa) screening program. All of them presented PSA values between 4 and 10 ng/ml, normal digital rectal examination, and a transrectal ultrasound (TRUS) guided biopsy available (PSA>/=4 ng/ml as the sole criterion for biopsy). Multivariate analysis failed to demonstrate higher PSAD values in men with PCa. PSAD cutoff points higher than 0.07 ng/ml per cc were considered as unacceptable, with less than 95% sensitivity. When a cutoff point of 0.15 was considered, as many as 30.6% of the cancers were missed. In conclusion we cannot recommend the use of this parameter for the above mentioned purpose.Prostate Cancer and Prostatic Diseases (2001) 4, 146-149.

Detecting circulating prostate cells in patients with clinically localized prostate cancer: clinical implications for molecular staging.

OBJECTIVE: To evaluate the clinical utility of using the reverse transcriptase-polymerase chain reaction (RT-PCR) to detect prostate-specific antigen (PSA) mRNA in peripheral blood samples from patients with prostate cancer, as a predictor of extraprostatic disease, and to assess any correlations with known predictive markers of this condition. PATIENTS AND METHODS: Immediately before radical prostatectomy, peripheral blood samples were taken from 25 men with clinically localized prostate cancer and analysed for PSA mRNA using RT-PCR (in 'hot-start' conditions and confirmed using ClaI restriction enzyme). The relationships between PSA mRNA positivity, pathological and clinical features were analysed; PSA mRNA positivity, PSA level and biopsy Gleason score were then compared as predictors of extraprostatic disease. RESULTS: There was no relationship between PSA mRNA positivity and pathological stage (pT2 or pT3), and no association between PSA mRNA positivity and serum PSA level, PSA density, the findings on a digital rectal examination or transrectal ultrasonography, and perineural invasion in the prostatic biopsy. However, there was a significant correlation between the Gleason score of the preoperative biopsy and PSA mRNA positivity. The best predictors of extraprostatic disease were the biopsy Gleason score and the PSA level. CONCLUSION: There was no significant advantage in using the RT-PCR assay of PSA mRNA before surgery to stage prostate cancer and to discriminate between organ-confined and extraprostatic neoplasms.

Role of autonomic innervation in rat prostatic structure maintenance: a morphometric analysis.

PURPOSE: To analyze the effects of major pelvic ganglion (MPG) excision on the structure of rat prostate. MATERIALS AND METHODS: We studied 80 Sprague-Dawley rats (300-350 gm. weight). Forty-two were anesthetized and the right MPG excised. After 28-30 days, the same-side prostatic ventral lobe (VL) was obtained for macroscopic, light (LM), and transmission electron microscopy (TEM) evaluation. A computerized morphometric analysis was performed on epithelial and muscle cells. Results were compared with 38 right VL of non-operated, same-aged rats. RESULTS: A 36.6% reduction (0.14 gm.) of VL fresh weight was found in the denervated group (p <0.001). Mean tissue proportions observed in the LM study were 27.9% (epithelial), 48.3% (stromal), and 51.8% (glandular) in the non-operated group, versus 14.8% (p <0.001), 55.7%, and 44.4% (not significant) respectively, after MPG excision. No difference was found regarding the vascular pattern. In the denervated rats, TEM analysis found a significant reduction in total and supranuclear cell height (change in cell polarity), as well as in cytoplasm, Golgi and endoplasmic reticulum areas. Secretory granule count, total area (p <0.001), and density of apical microvilli were also reduced. On the other hand, only an increase in the area of cytoplasm ribosomal aggregates was detected in the smooth muscle cell analysis. CONCLUSIONS: Our study demonstrated a rat prostatic VL atrophy in the denervated side, due to a shrinkage in the epithelial component of the gland. Ultrastructural findings also suggest an overall decrease of epithelial cell secretory activity. Finally, the increase of ribosomal aggregates found in stromal smooth muscle could reflect an activation of these cells after denervation.

Interleukin-1 beta stimulates sphingomyelin hydrolysis in cultured granulosa cells: evidence for a regulatory role of ceramide on progesterone and prostaglandin biosynthesis.

In granulosa cells labeled to isotopic steady-state with [3H]serine, addition of interleukin-1 beta (IL1 beta) or bacterial sphingomyelinase (SMase) induced a rapid decrease (approximately 60% by 10 min) in cellular [3H]Sphingomyelin content and a prolonged generation (up to 60 min) of [3H]ceramide, the immediate lipid-moiety generated in response to sphingomyelin hydrolysis. In FSH-treated cells, IL1 beta (0.3-30 ng/ml) inhibited progesterone biosynthesis in a dose-dependent manner, an effect that was also observed in cells exposed to increasing concentrations of bacterial SMase (0.003-0.3 U/ml) or the membrane-permeable ceramide analogue N-hexanoylsphingosine (C6-cer:0.1-10 microM). Abrogation of progesterone biosynthesis was not a sole consequence of inadequate cAMP biosynthesis because cyclic nucleotide levels remained elevated (3- to 4-fold over untreated cultures) after addition of IL1 beta, SMase, or two different cell permeable ceramide analogues (C2-cer and C6-cer) to gonadotropin-stimulated granulosa cells. Moreover, taken into account that exogenous SMase or C6-cer partially abolished progesterone biosynthesis induced by But2cAMP (0.5 mM) or cholera toxin (CTX: 1 microgram/ml), the above mentioned results support the notion that activation of the sphingomyelin pathway exerts its inhibitory effects on granulosa cell steroidogenic activity at site(s) of action both proximal and distal to cAMP generation. As determined by RT-PCR analysis, the inhibitory effect of IL1 beta, SMase, or C6-cer on gonadotropin-stimulated steroidogenesis was accompanied by arrested transcription of the mitochondrial cholesterol side chain cleavage enzyme (P450scc) and 3 beta-hydroxysteroid dehydrogenase/delta 5-4isomerase, the two FSH-inducible steps involved in progesterone biosynthesis. Although bacterial SMase or the ceramide analogue C6-cer alone did not exactly reproduce the effect of IL1 beta on granulosa cell prostaglandin E2 (PGE2) biosynthesis, both agents augmented net PGE2 production and messenger RNA levels of the inducible prostaglandin endoperoxide synthase/cyclooxygenase (PGHS-2) in cytokine-treated cells. Although the effect on PGHS-2 messenger RNA may account for the facilitatory role of ceramide on IL1 beta-induced PGE2 biosynthesis, neither SMase nor the membrane-permeant ceramide analogue were able to augment prostaglandin accumulation in the presence of exogenously added arachidonate precursor. Collectively, whereas these results show that ceramide triggers a negative-effector pathway that is both necessary and sufficient to reproduce the inhibitory effect of IL1 beta on FSH-stimulated granulosa cell steroidogenesis, they also support the notion that sphingomyelin hydrolysis may be important for cytokine-induced PGHS-2 expression but not sufficient to reproduce IL1 beta-stimulated PGE2 biosynthesis.

Ceramide mediates tumor necrosis factor effects on P450-aromatase activity in cultured granulosa cells.

In [3H]serine-labelled granulosa cells treatment with TNF alpha (10 ng/ml) resulted in a transient decrease in cellular [3H]sphingomyelin and generation of [3H]ceramide that remained elevated 60 min later. In cells labelled with [methyl-14C]choline, TNF alpha induced a similar reduction in [14C]sphingomyelin content that was accompanied by a sustained elevation in [14C]phosphorylcholine levels. In FSH-primed cells, TNF alpha inhibited P450-AROM activity in a dose-dependent manner, an effect that was also observed in cells treated with bacterial sphingomyelinase (SMase 0.003-0.3 U/ml) or increasing concentrations (0.1-10 microM) of N-acetylsphingosine (C2-cer) a membrane-permeable analogue of ceramide. These results support the notion that sphingomyelin degradation to a bioeffector molecule ceramide, may be an early event involved in TNF alpha-induced signal transduction in granulosa cells.

Effects of tetrandrine on Ca(2+)- and Na(+)-currents of single bullfrog cardiomyocytes.

Tetrandrine is a natural alkaloid classified as a calcium antagonist. However, its precise actions on Ca(2+)-currents in cardiac cells have not been fully characterized. In the present study, we have investigated the mechanism of action of tetrandrine on the Ca(2+)-currents of single bullfrog cardiac cells, using the patch-clamp technique. Tetrandrine slightly increased ICaL from negative holding potentials (-100 mV) at low concentrations (10 nM-1 microM) and inhibited it at higher concentrations. At depolarized holding potentials (-50 mV) only an enhanced inhibition was seen. Tetrandrine blockade of the L-type Ca(2+)-current (ICaL) was mostly tonic. This is similar to ICaL blockade by nifedipine but not by verapamil, the latter being mostly use-dependent. Use-dependent effects of tetrandrine and nifedipine were evident at high rates. Availability curves were shifted leftwards (10-12 mV) by tetrandrine (10 microM) and nifedipine (1 microM). The T-type Ca(2+)-current (ICaT), although less sensitive, was decreased by both agents in a voltage-independent way. Tetrandrine (10-30 microM) but not nifedipine (1-10 microM), depressed the Na(+)-current (INa) in tonic, use- and voltage-dependent manners. We conclude that tetrandrine and nifedipine share some common actions on cardiac Ca(2+)-channels, while showing differences in their actions on Na(+)-channels. The depression of INa by tetrandrine suggests it could be effective on supraventricular tachycardias.

The androgen receptor does not mediate progestin regulation of progesterone biosynthesis in cultured rat granulosa cells.

In the present investigation the influence of androgens and progestins on the FSH modulation of progesterone biosynthesis was studied in cultured rat granulosa cells. Cells obtained from the ovaries of immature estrogen treated rats were cultured for three days in serum free medium or in medium supplemented with FSH or CPA, with or without reduced androgen DHT or the synthetic progestin R5020 alone or in combination with the anti-androgen CPA. Treatment with FSH increased pregnenolone, progesterone and 20 alpha-OHP accumulation in the culture medium 20-, 14- and 7-fold, respectively. Furthermore FSH increased the activity of the enzyme 3 beta-HSD. Concurrent treatment with DHT or R5020 augmented the FSH stimulated steroidogenesis of cultured cells. The androgen enhancement of FSH stimulated steroidogenesis of cultured granulosa cells was blocked by concomitant treatment with CPA, whereas treatment of cultures with anti-androgen did not affect the stimulatory effect of the synthetic progestin R5020.