Magnetic nanoscaled Fe(3)O(4)/CeO(2) composite was prepared by the impregnation method and characterized as a heterogeneous Fenton-like catalyst for 4-chlorophenol (4-CP) degradation. The catalytic activity was evaluated in view of the effects of various processes, pH value, catalyst addition, hydrogen peroxide (H(2)O(2)) concentration, and temperature, and the pseudo-first-order kinetic constant of 0.11 min(-1) was obtained for 4-CP degradation at 30 °C and pH 3.0 with 30 mM H(2)O(2), 2.0 g L(-1) Fe(3)O(4)/CeO(2), and 0.78 mM 4-CP. The high utilization efficiency of H(2)O(2), calculated as 79.2%, showed a promising application of the catalyst in the oxidative degradation of organic pollutants. The reusability of Fe(3)O(4)/CeO(2) composite was also investigated after six successive runs. On the basis of the results of metal leaching, the effects of radical scavengers, intermediates determination, and X-ray photoelectron spectroscopic (XPS) analysis, the dissolution of Fe(3)O(4) facilitated by CeO(2) played a significant role, and 4-CP was decomposed mainly by the attack of hydroxyl radicals (•OH), including surface-bound •OH(ads) generated by the reaction of Fe(2+) and Ce(3+) species with H(2)O(2) on the catalyst surface, and •OH(free) in the bulk solution mainly attributed to the leaching of Fe.

The era of biologic medical therapies provides new options for patients with treatment-resistant inflammatory eye disease. In this review, the authors summarize current published experience in a rapidly progressing clinical field, including the use of biologics, such as the tumour necrosis factor blockers, daclizumab and rituximab, and related agents, interferons and intravenous immunoglobulin, for the treatment of uveitis, scleritis and orbital inflammation. Reports of dramatic recoveries in patients with recalcitrant ocular inflammation who have received such therapies must be balanced against the high cost of biologics and the potential for serious, and at times unanticipated, complications of this treatment.

One-dimensional (1D) metal-oxide nanostructures are ideal systems for exploring a large number of novel phenomena at the nanoscale and investigating size and dimensionality dependence of nanostructure properties for potential applications. The construction and integration of photodetectors or optical switches based on such nanostructures with tailored geometries have rapidly advanced in recent years. Active 1D nanostructure photodetector elements can be configured either as resistors whose conductions are altered by a charge-transfer process or as field-effect transistors (FET) whose properties can be controlled by applying appropriate potentials onto the gates. Functionalizing the structure surfaces offers another avenue for expanding the sensor capabilities. This article provides a comprehensive review on the state-of-the-art research activities in the photodetector field. It mainly focuses on the metal oxide 1D nanostructures such as ZnO, SnO(2), Cu(2)O, Ga(2)O(3), Fe(2)O(3), In(2)O(3), CdO, CeO(2), and their photoresponses. The review begins with a survey of quasi 1D metal-oxide semiconductor nanostructures and the photodetector principle, then shows the recent progresses on several kinds of important metal-oxide nanostructures and their photoresponses and briefly presents some additional prospective metal-oxide 1D nanomaterials. Finally, the review is concluded with some perspectives and outlook on the future developments in this area.

Animal feeding operations (AFOs) and wastewater treatment plants (WWTPs) are potential sources of antibiotic resistance genes (ARGs) in rivers and/or antibiotics that may select for ARGs in native river bacteria. This study aimed to identify ARG distribution patterns that unambiguously distinguish putative sources of ARG from a native river environment. Such molecular signatures may then be used as tracers of specific anthropogenic sources. Three WWTPs, six AFO lagoons, and three sites along a pristine region of the Cache la Poudre (Poudre) River were compared with respect to the frequency of detection (FOD) of 11 sulfonamide and tetracycline ARGs. Principle-component and correspondence analyses aided in identifying the association of tet(H), tet(Q), tet(S), and tet(T) (tet group HQST) with AFO environments and tet(C), tet(E), and tet(O) (tet group CEO) with WWTPs. Discriminant analysis indicated that both tet group HQST and tet group CEO correctly classified the environments, but only the tet group HQST provided a significant difference in FOD among the environments (p < 0.05). Sul(I) was detected in 100% of the source environments but just once in the pristine Poudre River, which was dominated by tet(M) and tet(W). Tet(W) libraries generated from the pristine Poudre River, WWTPs, and AFO lagoons were also discernible based on restriction fragment length polymorphism and phylogenetic analysis. Thus, a novel approach was developed and demonstrated to be effective for the model river system, taking an important step in advancing the fundamental understanding of ARG transport in the environment.

Association of cellular influences and physical and chemical properties were examined for 24 kinds of industrial metal oxide nanoparticles: ZnO, CuO, NiO, Sb(2)O(3), CoO, MoO(3), Y(2)O(3), MgO, Gd(2)O(3), SnO(2), WO(3), ZrO(2), Fe(2)O(3), TiO(2), CeO(2), Al(2)O(3), Bi(2)O(3), La(2)O(3), ITO, and cobalt blue pigments. We prepared a stable medium dispersion for each nanoparticle and examined the influence on cell viability and oxidative stress together with physical and chemical characterizations. ZnO, CuO, NiO, MgO, and WO(3) showed a large amount of metal ion release in the culture medium. The cellular influences of these soluble nanoparticles were larger than insoluble nanoparticles. TiO(2), SnO(2), and CeO(2) nanoparticles showed strong protein adsorption ability; however, cellular influences of these nanoparticles were small. The primary particle size and the specific surface area seemed unrelated to cellular influences. Cellular influences of metal oxide nanoparticles depended on the kind and concentrations of released metals in the solution. For insoluble nanoparticles, the adsorption property was involved in cellular influences. The primary particle size and specific surface area of metal oxide nanoparticles did not affect directly cellular influences. In conclusion the most important cytotoxic factor of metal oxide nanoparticles was metal ion release.

Oocyte development is characterized by impressive changes in chromatin structure and function in the germinal vesicle (GV) that are crucial in conferring to the oocyte meiotic and developmental competence. During oogenesis, oocyte and follicular cells communicate by paracrine and junctional mechanisms. In cow, cumulus-enclosed oocytes (CEOs) isolated from early antral follicles have uncondensed chromatin (GV0), functionally open gap junction (GJ)-mediated communications, and limited meiotic competence. The aim of the present study was to analyze the role of GJ communications on the chromatin remodeling process during the specific phase of folliculogenesis that coincides with the transcriptional silencing and the sequential acquisition of meiotic and developmental capability. CEOs were cultured in a follicle-stimulating hormone-based culture system that sustained GJ coupling and promoted oocyte growth and transition from GV0 to higher stages of condensation. When GJ functionality was experimentally interrupted, chromatin rapidly condensed, and RNA synthesis suddenly ceased. These effects were prevented by the addition of cilostamide, a phosphodiesterase 3 inhibitor, indicating that the action of GJ-mediated communication on chromatin structure and function is mediated by cAMP. Prolonging GJ coupling during oocyte culture before in vitro maturation enhanced the ability of early antral oocytes to undergo meiosis and early embryonic development. Altogether, the evidence suggests that GJ-mediated communication between germinal and somatic compartments plays a fundamental role in the regulation of chromatin remodeling and transcription, which in turn are related to competence acquisition.

In women, type 1 diabetes is associated with an increased risk of poor prenatal outcomes such as congenital anomalies and early miscarriage. In murine models of type 1 diabetes, impaired oocyte meiotic maturation, abnormal oocyte metabolism, and increased granulosa cell apoptosis have been noted. because gap junction communication is critical for the regulation of oocyte growth and meiotic maturation, we investigated the level of communication between the oocyte and surrounding cumulus cells in a streptozotocin-induced type 1 diabetic B6SJL/F1 mouse model and the expression of gap junction proteins known as connexins. Fluorescence recovery after photobleaching analyses of cumulus cell-enclosed oocytes (CEOs) from diabetic mice showed a 60% decrease in communication as compared with CEOs from nondiabetic mice. Real-time RT-PCR analyses confirmed the presence of Cx26, Cx37, and Cx57 mRNA and revealed a significant decrease in Cx37 mRNA expression in oocytes from diabetic mice compared with nondiabetic mice. Western analyses detected Cx26 expression in CEO but not denuded oocyte (DO) samples, and Cx37 in DO samples. Cx26 protein levels were decreased by 78% in CEOs from diabetic mice, and Cx37 protein levels were decreased 36% in DOs from diabetic mice. This decrease in connexin expression and gap junction communication in CEOs from diabetic mice may be responsible for the impaired oocyte meiotic maturation and poor pregnancy outcomes.

In the present study, we have utilized a streptozotocin-induced diabetic mouse model to examine how the diabetic condition and different glucose concentrations affect several parameters of reproductive physiology. We report that oocyte maturation is altered under all experimental conditions examined. In cumulus cell-enclosed oocytes (CEO) from diabetic mice, spontaneous maturation was accelerated but the FSH-mediated delay of spontaneous maturation was suppressed. Higher glucose levels in the culture medium suppressed spontaneous maturation but did not influence the transient arrest mediated by FSH. Meiotic arrest in CEO by hypoxanthine and dibutyryl cAMP (dbcAMP) was less effective at higher glucose concentrations. In addition, both FSH-induced maturation in vitro and hCG-induced maturation in vivo were reduced by the diabetic condition. The ovulation rate was lowered by about 50% in diabetic mice and fewer ovulated ova had reached metaphase II. Despite the decreased number of ova at metaphase II, in vitro cultures showed the oocytes were capable of completing meiotic maturation at control levels. Insulin treatment reversed the detrimental effects of diabetes on meiotic induction, ovulation, and completion of meiotic maturation. Cultures of pronuclear-staged embryos confirmed a negative effect of diabetes and hyperglycemia on development to the blastocyst stage. These data suggest that defects in meiotic regulation brought about by the diabetic condition are due to decreased communication between the somatic and germ cell compartments, and it is concluded that such conditions may contribute to postfertilization developmental abnormalities.

Clinical and Experimental Optometry, in conjunction with Optometrists Association Australia and Professor Shaun P Collin of the University of Queensland, announce the launch of a web-based archive of previously published topographic maps of retinal cell distribution in vertebrates. At present, the archive boasts more than 770 different maps of the distribution of retinal neurons (for example, photoreceptors, bipolar cells, amacrine cells, horizontal cells and ganglion cells) in nearly 200 species within all vertebrate classes (Cephalospidomorpha, Actinopterygii, Sarcopterygii, Amphibia, Reptilia, Aves and Mammalia). The distribution of retinal neurons has been studied for more than 100 years and has become a powerful means of predicting the spatial resolving power of the eye and the retinal regions containing specialisations, such as areae centrales, horizontal streaks and foveae, where increased densities of neurons define the way in which a species visually samples its environment. The location of these retinal specialisations thereby identifies the part(s) of the visual field of critical importance for localising food and mates and for predator surveillance. The distribution of sampling elements even reflects the symmetry of a species' ecological habitat. The archive is a unique collection of most of the currently available retinal maps, which also presents relevant information, where known, about eye size, retinal cell density, retinal orientation, cell number, spatial resolving power and the type of specialisation, in addition to basic physical parameters of each species (body size, weight, sex and developmental stage). The archive is accessible at http://www.optometrists.asn.au/ceo/retinalsearch and will be updated regularly. The powerful database is interactive and freely available, providing the opportunity to upload both published and unpublished topographic maps. Following a review process, previously unpublished maps will be 'published' and available online worldwide. It is hoped that this comprehensive new resource will provide not only an up-to-date method of accessing maps of the distribution of retinal neurons in individual species but also allow broader evolutionary comparisons of the visual capabilities, ecology, development and the type(s) of retinal specialisations found in vertebrates.

Cyclic adenosine monophosphate (cAMP) has been implicated as an important regulator of meiotic maturation in mammalian oocytes. A decrease in cAMP, brought about by the action of cAMP phosphodiesterase (PDE), is thought to initiate germinal vesicle breakdown (GVB) by the inactivation of cAMP-dependent protein kinase. However, the product of PDE activity, 5'-AMP, is a potent activator of an important regulatory enzyme, AMP-activated protein kinase (AMPK). The aim of this study was to evaluate a possible role for AMPK in meiotic induction, using oocytes obtained from eCG-primed, immature mice. Alpha-1 and -2 isoforms of the catalytic subunit of AMPK were detected in both oocytes and cumulus cells. When 5-aminoimidazole-4-carboxamide 1-beta-d-ribofuranoside (AICA riboside), an activator of AMPK, was tested on denuded oocytes (DO) and cumulus cell-enclosed oocytes (CEO) maintained in meiotic arrest by dbcAMP or hypoxanthine, GVB was dose-dependently induced. Meiotic induction by AICA riboside in dbcAMP-supplemented medium was initiated within 3 h in DO and 4 h in CEO and was accompanied by increased AMPK activity in the oocyte. AICA riboside also triggered GVB when meiotic arrest was maintained with hypoxanthine, 8-AHA-cAMP, guanosine, or milrinone, but was ineffective in olomoucine- or roscovitine-arrested oocytes, indicating that it acts upstream of maturation-promoting factor. Adenosine monophosphate dose-dependently stimulated GVB in DO when meiotic arrest was maintained with dbcAMP or hypoxanthine. This effect was not mimicked by other monophosphate or adenosine nucleotides and was not affected by inhibitors of ectophosphatases. Combined treatment with adenosine and deoxycoformycin, an adenosine deaminase inhibitor, stimulated GVB in dbcAMP-arrested CEO, suggesting AMPK activation due to AMP accumulation. It is concluded that phosphodiesterase-generated AMP may serve as a transducer of the meiotic induction process through activation of AMPK.

Nanoparticles (NPs) are reported to be a potential environmental health hazard. For organisms living in the aquatic environment, there is uncertainty on exposure because of a lack of understanding and data regarding the fate, behavior, and bioavailability of the nanomaterials in the water column. This paper reports on a series of integrative biological and physicochemical studies on the uptake of unmodified commercial nanoscale metal oxides, zinc oxide (ZnO), cerium dioxide (CeO(2)), and titanium dioxide (TiO(2)), from the water and diet to determine their potential ecotoxicological impacts on fish as a function of concentration. Particle characterizations were performed and tissue concentrations were measured by a wide range of analytical methods. Definitive uptake from the water column and localization of TiO(2) NPs in gills was demonstrated for the first time by use of coherent anti-Stokes Raman scattering (CARS) microscopy. Significant uptake of nanomaterials was found only for cerium in the liver of zebrafish exposed via the water and ionic titanium in the gut of trout exposed via the diet. For the aqueous exposures undertaken, formation of large NP aggregates (up to 3 mum) occurred and it is likely that this resulted in limited bioavailability of the unmodified metal oxide NPs in fish.

Three studies examined the relationships among anger, gender, and status conferral. As in prior research, men who expressed anger in a professional context were conferred higher status than men who expressed sadness. However, both male and female evaluators conferred lower status on angry female professionals than on angry male professionals. This was the case regardless of the actual occupational rank of the target, such that both a female trainee and a female CEO were given lower status if they expressed anger than if they did not. Whereas women's emotional reactions were attributed to internal characteristics (e.g., "she is an angry person,""she is out of control"), men's emotional reactions were attributed to external circumstances. Providing an external attribution for the target person's anger eliminated the gender bias. Theoretical implications and practical applications are discussed.

Modified-live (ML) infectious laryngotracheitis (ILT) vaccine viruses, both tissue-culture-origin (TCO) and chicken-embryo-origin (CEO), were passaged 20 times in specific-pathogen-free chickens. After serial bird-to-bird passage, increased virulence was observed for CEO virus but not TCO virus. Increased mortality and increased severity and duration of respiratory disease were observed in chickens inoculated with chicken-passaged CEO viruses; only mild respiratory disease (no mortality) occurred in chickens inoculated with chicken-passaged TCO viruses. These findings suggest that ML ILT vaccine viruses may increase in virulence after bird-to-bird passage.

OBJECTIVE

Patients presenting with presumed infective keratitis were studied to determine predisposing factors, the current susceptibilities of the bacterial isolates to a range of relevant antibiotics, the success rate of topical antibiotic treatment of keratitis and predictors of failure of topical therapy.

METHODS

Corneal scrapings taken from patients who presented between January 2002 and December 2003 to the Sydney Eye Hospital Emergency Department with keratitis were cultured. The minimum inhibitory concentration of selected antibiotics was determined for each bacterial isolate using an agar dilution technique.

RESULTS

One hundred and twelve consecutive patients presented with corneal ulcers. Forty-seven of the 112 (42%) patients had a growth from the corneal scraping. Potential predisposing factors were identified in 64% of patients, most frequently contact lens wear (36% of patients). Coagulase-negative staphylococci were the most common species isolated. Other common organisms isolated include Pseudomonas aeruginosa, Corynebacterium spp., Staphylococcus aureus and Streptococcus spp.

CONCLUSIONS

Most microorganisms isolated from patients with bacterial keratitis showed susceptibility to ciprofloxacin and aminoglycosides. Cephalothin plus aminoglycoside constituted an effective initial broad-spectrum antibiotic combination. The success rate of topical antibiotic treatment of corneal abscess is 89%. Predictors of failure include older age group, medium or large ulcer, culture-negative keratitis, hypopyon and poor visual acuity.

Biotransformation is a critical factor that may modify the toxicity, behavior, and fate of engineered nanoparticles in the environment. CeO(2) nanoparticles (NPs) are generally recognized as stable under environmental and biological conditions. The present study aims to investigate the biotransformation of CeO(2) NPs in plant systems. Transmission electron microscopy (TEM) images show needlelike clusters on the epidermis and in the intercellular spaces of cucumber roots after a treatment with 2000 mg/L CeO(2) NPs for 21 days. By using a soft X-ray scanning transmission microscopy (STXM) technique, the needlelike clusters were verified to be CePO(4). Near edge X-ray absorption fine structure (XANES) spectra show that Ce presented in the roots as CeO(2) and CePO(4) while in the shoots as CeO(2) and cerium carboxylates. Simulated studies indicate that reducing substances (e.g., ascorbic acids) played a key role in the transformation process and organic acids (e.g., citric acids) can promote particle dissolution. We speculate that CeO(2) NPs were first absorbed on the root surfaces and partially dissolved with the assistance of the organic acids and reducing substances excreted by the roots. The released Ce(III) ions were precipitated on the root surfaces and in intercellular spaces with phosphate, or form complexes with carboxyl compounds during translocation to the shoots. To the best of our knowledge, this is the first report confirming the biotransformation and in-depth exploring the translocation process of CeO(2) NPs in plants.

This study examined the effects of three different cellular stresses on oocyte maturation in meiotically arrested mouse oocytes. Cumulus-cell enclosed oocytes (CEO) or denuded oocytes (DO) from immature, eCG-primed mice were cultured for 17-18 h in dbcAMP-containing medium plus increasing concentrations of the metabolic poison, sodium arsenite, or the free radical-generating agent, menadione. Alternatively, oocytes were exposed to osmotic stress by pulsing with sorbitol and returned to control inhibitory conditions for the duration of culture. Arsenite and menadione each dose-dependently induced germinal vesicle breakdown (GVB) in both DO and CEO. DO, but not CEO, pulsed for 60 min with 500 mM sorbitol were stimulated to resume maturation. The lack of effect in CEO suggests that the cumulus cells may be playing a protective role in osmotic stress-induced GVB. The AMP-activated protein kinase (PRKA; formerly known as AMPK) inhibitors, compound C and araA, completely blocked the meiosis-stimulating effects of all the tested stresses. Western blots showed that acetyl-CoA carboxylase, an important substrate of PRKA, was phosphorylated before GVB, supporting a role for PRKA in stress-induced maturation. Together, these data show that a variety of stresses stimulate GVB in meiotically arrested mouse oocytes in vitro and suggest that this effect is mediated through activation of PRKA.

BACKGROUND

The Institute of Medicine has recommended establishing mandatory error reporting systems for hospitals and other health settings.

OBJECTIVE

To examine the opinions and experiences of hospital leaders with state reporting systems.

METHODS

Survey of chief executive and chief operating officers (CEOs/COOs) from randomly selected hospitals in 2 states with mandatory reporting and public disclosure, 2 states with mandatory reporting without public disclosure, and 2 states without mandatory systems in 2002-2003.

METHODS

Perceptions of the effects of mandatory systems on error reporting, likelihood of lawsuits, and overall patient safety; attitudes regarding release of incident reports to the public; and likelihood of reporting incidents to the state or to the affected patient based on hypothetical clinical vignettes that varied the type and severity of patient injury.

RESULTS

Responses were received from 203 of 320 hospitals (response rate = 63%). Most CEOs/COOs thought that a mandatory, nonconfidential system would discourage reporting of patient safety incidents to their hospital's own internal reporting system (69%) and encourage lawsuits (79%) while having no effect or a negative effect on patient safety (73%). More than 80% felt that the names of both the hospital and the involved professionals should be kept confidential, although respondents from states with mandatory public disclosure systems were more willing than respondents from the other states to release the hospital name (22% vs 4%-6%, P = .005). Based on the vignettes, more than 90% of hospital leaders said their hospital would report incidents involving serious injury to the state, but far fewer would report moderate or minor injuries, even when the incident was of sufficient consequence that they would tell the affected patient or family.

CONCLUSIONS

Most hospital leaders expressed substantial concerns about the impact of mandatory, nonconfidential reporting systems on hospital internal reporting, lawsuits, and overall patient safety. While hospital leaders generally favor disclosure of patient safety incidents to involved patients, fewer would disclose incidents involving moderate or minor injury to state reporting systems.

Many properties provided by supramolecular chemistry, nanotechnology and catalysis only appear in solids exhibiting large surface areas and regular porosity at the nanometre scale. In nanometre-sized particles, the ratio of the number of atoms in the surface to the number in the bulk is much larger than for micrometre-sized materials, and this can lead to novel properties. Here we report the preparation of a hierarchically structured mesoporous material from nanoparticles of CeO(2) of strictly uniform size. The synthesis involves self-assembly of these 5-nm CeO(2) pre-treated nanoparticles in the presence of a structure directing agent (poly(alkylene oxide) block polymer). The walls of this hexagonal structured CeO(2) material are formed from the primary nanoparticles. The material possesses large pore volumes, high surface areas, and marked thermal stability, allowing it to be easily doped after synthesis whilst maintaining textural and mechanical integrity. It also exhibits a photovoltaic response, which is directly derived from the nanometric particle size-normal CeO(2) does not show this response. We have constructed operational organic-dye-free solar cells using nanometric ceria particles (in both mesostructured or amorphous forms) as the active component, and find efficiencies that depend on the illuminating power.

BACKGROUND

Despite significant interest in the business case for quality improvement (QI), there are few evaluations of the impact of QI programs on outpatient organizations. The financial impact of the Health Disparities Collaboratives (HDC), a national QI program conducted in community health centers (HCs), was examined.

METHODS

Chief executive officers (CEOs) from health centers in two U.S. regions that participated in the Diabetes HDC (N = 74) were surveyed. In case studies of five selected centers, program costs/revenues, clinical costs/revenues, overall center financial health, and indirect costs/benefits were assessed.

RESULTS

CEOs were divided on the HDC's overall effect on finances (38%, worsened; 48%, no change; 14%, improved). Case studies showed that the HDC represented a new administrative cost ($6-$22/patient, year 1) without a regular revenue source. In centers with billing data, the balance of diabetes-related clinical costs/revenues and payor mix did not clearly worsen or improve with the program's start. The most commonly mentioned indirect benefits were improved chronic illness care and enhanced staff morale.

CONCLUSIONS

CEO perceptions of the overall financial impact of the HDC vary widely; the case studies illustrate the numerous factors that may influence these perceptions. Whether the identified balance of costs and benefits is generalizable or sustainable will have to be addressed to optimally design financial reimbursement and incentives.

BACKGROUND

The provision of family-centred services (FCS) emphasizes a partnership between parents and service providers so that families are involved in every aspect of services for their child. There is evidence that providing FCS is associated with improvements in parents' satisfaction with services, decreased parental stress, and positive child outcomes.

METHODS

The purpose of this study was to examine factors that are most important in determining parent perceptions of the family centredness of care and parent satisfaction with service. A cross-sectional survey was completed by 494 parents, 324 service providers, and 15 CEOs from 16 organizations delivering children's rehabilitation services. Analyses were completed using a structural equation modelling approach.

RESULTS

Survey return rates ranged from 77 to 94%. Findings indicate that the principal determinants of parent satisfaction with services are the family-centred culture at the organization and parent perceptions of FCS. Parent satisfaction with services was also influenced by the number of places where services were received and the number of health and development problems experienced by their child.

CONCLUSIONS

Parent satisfaction with services is strongly influenced by the perception that services are more family centred, fewer places where services were received and fewer health and development problems for their child. Ways in which organizations can improve satisfaction through carrying out family-centred behaviours are discussed.

The corneal epithelium is a self-renewing tissue and must, by definition, have a resident basal cell population necessary for homeostasis and wound healing. There is a substantial body of evidence, both experimental and clinical, pointing to the basal cells of the limbus as the location of corneal epithelial stem cells. However, in the absence of a definitive marker of limbal stem cells, the evidence remains largely circumstantial. Many markers such as p63 and integrin alpha9 are preferentially localized to the limbus but cannot be regarded as stem cell-specific. Other markers such as K3 and connexin 43 can be regarded as markers of corneal differentiation. The discovery of stem cell markers in other organ systems, such as the haematopoietic system, offers optimism that a marker of limbal stem cells will one day be found. Such a discovery will have far-reaching implications for the study of ocular surface biology and stratified squamous epithelia in general.

The effect of the different follicular cell types on resumption of meiosis was studied during stimulation with FSH. Cumulus enclosed oocytes (CEO), denuded oocytes (DO), and cumulus and mural granulosa cells were used. The resumption of meiosis and oocyte maturation were assessed by the determination of the germinal vesicle breakdown (GVBD) and polar body formation (PB) at the end of a 24 hr culture period in the presence of 4 mM hypoxanthine (HX). The effects of recombinant LH (r-LH) and hCG were also evaluated. Oocyte exposure to the gonadotrophins varied from 5 min to 24 hr (i.e., priming time). Oocytes were obtained from immature gonadotrophin-stimulated and -unstimulated mice. 1. FSH (1 IU/L-75 IU/L) provoked a dose-dependent increase in GVBD and PB in CEO, but not in DO, in stimulated and unstimulated mice. Eight IU/L was sufficient for inducing resumption of meiosis. In contrast, LH and hCG (both 1 IU/L-1500 IU/L) were without effect on GVBD and PB in CEO and DO of oocytes from stimulated and unstimulated mice. A combination of 8 IU/L FSH and 4-8 IU/L hCG produced an additive effect, whereas combinations with LH and higher concentrations of hCG had no such effect. 2. A 2 hr priming with FSH (8 IU/L-75 IU/L) induced a dose-dependent oocyte maturation in CEO. Thirty minutes of priming with FSH (75 IU/L) was sufficient for induction of meiotic resumption in CEO. 3. Priming CEO with FSH for 2 hr followed by the separation and repooling of oocytes and cumulus cells induced oocyte maturation. GVBD of new, unprimed DO added to cumulus cells of primed CEO increased slightly but was significant, whereas GVBD in DO isolated from the primed CEO only increased marginally. DO cocultured with FSH-primed cumulus masses seem to be prevented from resuming meiosis. 4. Priming a coculture of granulosa cells and DO with FSH for 2 hr caused a significant increase in GVBD compared to the control, evaluated after 24 hr. In contrast, a 24 hr FSH-priming of a coculture of granulosa cells and DO was without effect on GVBD. 5. A spent medium in which unstimulated cumulus cells or mural granulosa cells had grown was without effect on GVBD in DO. However, a small fraction of the DO resumed meiosis after culture in a spent medium derived from a 2 hr priming of CEO and spent media from 24 hr priming of CEO induced a 2-3 times higher GVBD frequency in the DO compared to the controls. Heat treatment of spent media (70 degrees C, 30 min) from a 24 hr FSH-priming of CEO still induced GVBD in naive DO. The results showed that FSH, in a concentration of as little as 8 IU/L, but not r-LH and hCG, induced within 30 minutes the cumulus cells to produce and after 2 hr to secrete a diffusible heat stable meiosis activating substance. This substance overcame, in a paracrine fashion, the inhibiting effect of HX and induced oocyte maturation directly in DO. The production of this substance, however, was dependent on the initial connection between the cumulus cells and the oocyte, indicating an important 2-way communication between these 2 cell types. The mural granulosa cells did not produce a meiosis inducing activity by stimulation with FSH, but significantly, more DO matured after coculture with the nonstimulated granulosa cells for 24 hr than for 2 hr. It is proposed that the heat stable meiosis activating component of the spent media from the FSH-stimulated CEO belongs to the meiosis activating sterols, MAS, previously isolated from human follicular fluid and from adult bull testes.

We have previously shown that AMP-activated protein kinase (AMPK) can induce the resumption of meiosis in mouse oocytes maintained in meiotic arrest in vitro. The present study was carried out to determine whether AMPK activation is involved in hormone-induced maturation. Follicle-stimulating hormone (FSH) and the EGF-like peptide, amphiregulin (AR), are potent inducers of maturation in cumulus cell-enclosed oocytes (CEO). Within 3 h of FSH treatment, phospho-acetyl CoA carboxylase (ACC) levels were increased in germinal vesicle (GV)-stage oocytes when compared to non-stimulated controls and remained elevated throughout 9 h of culture, indicating AMPK activation. A similar response to AR was observed after 6 h of culture. Using anti-PT172 antibody (binds only to activated AMPK), Western analysis demonstrated active AMPK in both FSH- or AR-treated GV-stage oocytes within 6 h. The AMPK inhibitors, compound C and adenine 9-beta-d-arabinofuranoside (araA), blocked FSH- or AR-induced meiotic resumption and ACC phosphorylation, further supporting a causal role for AMPK in hormone-induced meiotic resumption. Immunocytochemistry using anti-PT172-AMPK antibody showed an increased diffuse cytoplasmic staining and more intense punctate staining in the germinal vesicles of oocytes following treatment with the AMPK activator 5-aminoimidazole-4-carboxamide-1-beta-d-ribofuranoside (AICAR) or with FSH or AR, and this staining was eliminated by compound C or a blocking peptide for the anti-PT172 antibody. Staining of oocytes from hCG-stimulated mice with the anti-PT172 antibody also showed pronounced label in the germinal vesicles within 1-2 h. Furthermore, in oocytes from all groups, active AMPK was always observed in association with the condensed chromosomes of maturing oocytes. Taken together, these results support a role for AMPK in FSH and AR-induced maturation in vitro and hCG-induced maturation in vivo.

Researchers have theorized that innate personal traits are related to leadership success. Although links between psychological characteristics and leadership success have been well established, research has yet to identify any objective physical traits of leaders that predict organizational performance. In the research reported here, we identified leaders' facial structure as a specific physical trait that correlates with organizational performance. Specifically, we found that firms whose male CEOs have wider faces (relative to facial height) achieve superior financial performance. Decision-making dynamics within a firm's leadership team moderate this effect, such that the relationship between a given CEO's facial measurements and his firm's financial performance is stronger in firms with cognitively simple leadership teams.