Limbal stem cell deficiency secondary to systemic paclitaxel (Taxol) for breast cancer: a case report.

BACKGROUND: Paclitaxel (PTX) is an antineoplastic drug widely used in treatments for ovarian, breast, and small-cell lung cancer. Although ocular effects associated with PTX have been previously described, very few studies have specifically reported systemic PTX as a contributing factor for limbal stem cell deficiency (LSCD), which is characterized by the loss of stem cell and barrier function of the limbus leading to progressive pain and reduction in visual acuity. Described here is a unique case where a patient was diagnosed with LSCD secondary to PTX use for the treatment of breast cancer, at doses of PTX far lower than what is reported in current literature. CASE PRESENTATION: A 73-year-old woman with a previous diagnosis of breast cancer with liver metastasis presented with a complaint of increasing pain in the left eye more than the right, along with decreasing visual acuity in both eyes following 3 months of PTX therapy for recurrent liver metastases. Upon examination, best-corrected visual acuity was 20/100 in the right eye and counting fingers on the left. Peripheral neovascularization, stromal scarring, and features of limbal stem cell deficiency (LSCD) were noted on the right cornea. A central neurotrophic ulcer with thinning to 50% and 360 degrees of conjunctivalization were noted on the left. After the discontinuation PTX with doxorubicin as the substitute, there was no further progression of her LSCD, and stabilization of her ocular surface was achieved. CONCLUSION: Although chemotherapy induced LSCD is a relatively rare adverse event, it is essential for clinicians starting new chemotherapy agents to consider the potential ocular toxicities that may result in their use. Ophthalmology review is recommended for patients after starting PTX therapy to assess for signs of LSCD, particularly in patients where drug toxicity can be aggravated due to impaired hepatic function.

Molecular analyses of circadian gene variants reveal sex-dependent links between depression and clocks.

An extensive literature links circadian irregularities and/or sleep abnormalities to mood disorders. Despite the strong genetic component underlying many mood disorders, however, previous genetic associations between circadian clock gene variants and major depressive disorder (MDD) have been weak. We applied a combined molecular/functional and genetic association approach to circadian gene polymorphisms in sex-stratified populations of control subjects and case subjects suffering from MDD. This approach identified significant sex-dependent associations of common variants of the circadian clock genes hClock, hPer3 and hNpas2 with major depression and demonstrated functional effects of these polymorphisms on the expression or activity of the hCLOCK and hPER3 proteins, respectively. In addition, hCLOCK expression is affected by glucocorticoids, consistent with the sex-dependency of the genetic associations and the modulation of glucocorticoid-mediated stress response, providing a mechanism by which the circadian clock controls outputs that may affect psychiatric disorders. We conclude that genetic polymorphisms in circadian genes (especially hClock and hPer3, where functional assays could be tested) influence risk of developing depression in a sex- and stress-dependent manner. These studies support a genetic connection between circadian disruption and mood disorders, and confirm a key connection between circadian gene variation and major depression.

Modified Miyake-Apple camera: illustration of deep anterior lamellar keratoplasty pearls learned from simultaneous anterior and posterior corneal imaging.

PURPOSE: The aim of this study was to demonstrate surgical pearls in big-bubble deep anterior lamellar keratoplasty using a modified Miyake-Apple camera system and to correlate these findings with histology. METHODS: This was a wet laboratory-based pilot study. Cadaveric human corneal tissue consented for research and not suitable for transplantation was fixed to a glass slide and assembled into the modified Miyake-Apple camera system. Dissections were performed and recorded. Selected specimens were submitted for light microscopy. RESULTS: Key points illustrated by video analysis included the entry of air into the artificial anterior chamber through the trabecular meshwork without Descemet membrane perforation, the contrast of this event with frank perforation, the potential of viscoelastic injection as a salvage maneuver, and the modes of air passage during the procedure. Histological correlation confirmed the air passage through the trabecular meshwork and demonstrated the appearance of pneumatized corneal stroma in the setting of a failed big-bubble and corneal "white-out." CONCLUSIONS: We present the video analysis that correlated with the histology of air behavior during big-bubble deep anterior lamellar keratoplasty. The chief points illustrated include signs associated with air entry into the eye in the presence and absence of Descemet perforation.

Modification of the Miyake-Apple technique for simultaneous anterior and posterior video imaging of wet laboratory-based corneal surgery.

PURPOSE: The aim of this study was to describe a modification of the Miyake-Apple posterior video analysis for the simultaneous visualization of the anterior and posterior corneal surfaces during wet laboratory-based deep anterior lamellar keratoplasty (DALK). METHODS: A human donor corneoscleral button was affixed to a microscope slide and placed onto a custom-made mounting box. A big bubble DALK was performed on the cornea in the wet laboratory. An 11-diopter intraocular lens was positioned over the aperture of the back camera of an iPhone. This served to video record the posterior view of the corneoscleral button during the big bubble formation. An overhead operating microscope with an attached video camcorder recorded the anterior view during the surgery. RESULTS: The anterior and posterior views of the wet laboratory-based DALK surgery were simultaneously captured and edited using video editing software. The formation of the big bubble can be studied. CONCLUSIONS: This video recording camera system has the potential to act as a valuable research and teaching tool in corneal lamellar surgery, especially in the behavior of the big bubble formation in DALK.

Evolving indications for and trends in keratoplasty in British Columbia, Canada, from 2002 to 2011: a 10-year review.

PURPOSE: The aim of this study was to report the evolving indications for keratoplasty and the shift in the type of keratoplasty performed in British Columbia, Canada, over a 10-year period from 2002 to 2011. METHODS: This was a retrospective database review of all the records of corneal transplant tissues at the Eye Bank of British Columbia, Canada, from January 2002 to December 2011. The patient demographics, indications, and types of transplant performed were analyzed. RESULTS: A total of 4843 corneal transplants were performed in 3742 patients (1968 male and 1774 female) from January 2002 to December 2011. The number of keratoplasties performed ranged from 420 in 2008 to 578 in 2011. The top 4 indications over the 10-year period were Fuchs endothelial dystrophy (FED; 18.9%), aphakic/pseudophakic bullous keratopathy (17.4%), regraft (17.1%), and keratoconus (15.5%). Penetrating keratoplasty (PKP) accounted for 86.5% (4191 transplants) of all keratoplasties performed. Since the introduction of Descemet stripping automated endothelial keratoplasty (DSAEK) in 2007, there was a significant increase in the number of DSAEKs (P < 0.0001) performed and a statistical decline in the number of PKPs (P < 0.0001) performed. Despite only 30 deep anterior lamellar keratoplasties being performed, an increasing trend was observed after 2008 (P = 0.0087). A decreasing trend in PKPs and an increasing trend in DSAEKs were observed for surgeries performed for FED, aphakic/pseudophakic bullous keratopathy, and regraft. CONCLUSIONS: FED has become the top indication for performing a keratoplasty over the 10-year period. There was a shift from PKP to DSAEK performed for endothelial failure. Although the number of deep anterior lamellar keratoplasty surgeries was small, there was a significant increasing trend.

Intention to engage in preventive behaviors in response to the A/H1N1 pandemic among university entrants in four Chinese cities.

This study examined the factors influencing the uptake of A/H1N1-related preventive behaviors among Chinese university students. During the 2009 A/H1N1 pandemic, a survey was administered to 2882 university students across 4 Chinese cities. We found greater self-efficacy and a stronger belief in the benefits of preventive behaviors to be associated with the intended adoption of preventive behaviors. However, knowledge about the transmission of A/H1N1 was not associated with the intent to engage in preventive behaviors. These results may be used to inform pandemic prevention campaigns for university students in the region.

Topography-guided laser refractive surgery.

PURPOSE OF REVIEW: Topography-guided laser refractive surgery regularizes the front corneal surface irregularities to achieve the desired refractive outcome. This is particularly applicable in highly aberrated corneas, where wavefront aberrometry is often not possible. This article aims to review the recently published results of topography-guided ablations in normal regular corneas, highly aberrated corneas, and its application in conjunction with collagen cross-linking (CXL) in cases of keratectasia. RECENT FINDINGS: Topography-guided laser ablation is increasingly used with good efficacy and safety outcomes in highly aberrated corneas with irregular astigmatism. These include eyes with refractive surgery complications including postlaser in-situ keratomileusis ectasia, decentered ablation, small optical zones, asymmetrical astigmatism, and postradial keratectomy astigmatism. Further indications are for postkeratoplasty astigmatism and keratoconus. Simultaneous topography-guided ablations with CXL in keratectasia have been promising, both in addressing the surface irregularities and progressive nature of the conditions. SUMMARY: Topography-guided laser refractive surgery is proving to be effective and well tolerated in the visual rehabilitation of highly aberrated eyes, with increasing predictability based on the recent research.

Clinical results of topography-based customized ablations in highly aberrated eyes and keratoconus/ectasia with cross-linking.

PURPOSE: To report results of a series of highly aberrated corneas treated with a topography-guided excimer laser ablation. METHODS: Retrospective, nonrandomized, consecutive series of eyes treated with topography-guided photorefractive keratectomy (TG-PRK) with the customized topographical neutralization technique (TNT). Cases included postoperative refractive surgery decentered ablations, optical zone enlargement, asymmetrical astigmatism, postoperative radial keratotomy (RK), postoperative keratoplasty, keratoconus combined with collagen cross-linking (CXL), and postoperative LASIK ectasia combined with CXL. Uncorrected distance visual acuity (UDVA), corrected distance visual acuity (CDVA), and manifest refraction were analyzed preoperatively and 6 months postoperatively. RESULTS: In decentered ablation cases, 94% of 37 eyes were within 1.00 diopter (D) of the attempted refractive outcome, with 76% within 0.50 D. Mean topographic, central, optical zone of uniform (monodioptric) power increased from 3.5 to 5.2 mm in 25 eyes. Thirty-one eyes treated for asymmetrical astigmatism showed improvement in cylinder from mean 1.31 to 0.52 D. Ten of 11 eyes treated for previous RK astigmatism achieved postoperative UDVA 20/40 or better. Twenty-seven eyes with postoperative keratoplasty astigmatism were treated, with 7 (25.9%) eyes gaining > or = 2 lines and 12 (44.4%) eyes gaining > or = 1 line of CDVA. Of eyes with keratoconus that were treated using TG-PRK with CXL, 42 (58%) eyes had UDVA 20/40 or better, and 66 (92%) eyes had CDVA 20/40 or better. Twelve (71%) of 17 eyes treated for postoperative LASIK ectasia using TG-PRK with CXL had UDVA 20/40 or better. Nine (53%) eyes gained > or = 2 lines of CDVA. CONCLUSIONS: Topography-guided laser treatment with custom TNT, combined with CXL in keratoconus and ectasia, is an effective, safe, and increasingly predictable option for highly aberrated corneas.

Larval settlement preference maximizes genetic mixing in an inbreeding population of a simultaneous hermaphrodite (Bugula stolonifera, Bryozoa).

Conspecific aggregations in terrestrial and aquatic organisms can have a significant effect on an individual's survival, growth and reproductive fitness, particularly if these aggregations are composed of closely related individuals. Such aggregations can form passively, as a consequence of dispersal, or actively, as a consequence of kin recognition. In this study, we investigated the genetic composition of individuals in conspecific aggregations in the simultaneous hermaphroditic marine bryozoan Bugula stolonifera. Conspecific larvae routinely metamorphose on adult colonies; the possibility that larvae select or avoid their maternal colony was investigated utilizing 10 newly developed polymorphic microsatellite loci. Adult colonies were collected from Eel Pond, Woods Hole, Massachusetts and inspected for the presence of attached individuals. Adult colonies and their attached individuals were genotyped and compared to assess genetic relatedness within and among these groups relative to the overall genetic variability of the sampling site. Overall, the population of B. stolonifera at this site was found to be outside Hardy-Weinberg equilibrium because of significant levels of inbreeding. No significant genetic differentiation, however, was found between any groups, documenting that a group containing an adult colony and its attached individuals had as much genetic variability as was found for the entire sampling site. Parentage-exclusion analyses showed that the vast majority of attached individuals (>93%) could not have derived from the colony on which they were attached. Kinship analyses showed that the majority of attached individuals (≈63%) shared less than a half-sibling relationship. These results suggest that a colony's nearest neighbours are not composed of siblings, and thus, larval settlement preference can maximize outcrossing in this inbreeding population.

Integrated HPLC-MS and (1)H-NMR spectroscopic studies on acyl migration reaction kinetics of model drug ester glucuronides.

Acyl glucuronides (AGs) are common, chemically reactive metabolites of acidic xenobiotics. Concerns about the potential of this class of conjugate to cause toxicity in man require efficient methods for the determination of reactivity, and this is commonly done by measuring transacylation kinetics. High-performance liquid chromatography-mass spectrometry (HPLC-MS) and nuclear magnetic resonance (NMR) spectroscopy were applied to the kinetic analysis of AG isomerization and hydrolysis for the 1-beta-O-AGs of ibufenac, (R)- and (S)-ibuprofen, and an alpha,alpha-dimethylated ibuprofen analogue. Each AG was incubated in either aqueous buffer at pH 7.4 or human plasma at 37 degrees C. Aliquots of these samples, taken throughout the reaction time course, were analysed by HPLC-MS and (1)H-NMR spectroscopy and the results compared. For identification of the AGs incubated in pH 7.4 buffer and for analysis of kinetic rates, (1)H-NMR spectroscopy generally gave the most complete set of data, but for human plasma the use of (1)H-NMR spectroscopy was impractical and HPLC-MS was more suitable. HPLC-MS was more sensitive than (1)H-NMR spectroscopy, but the lack of suitable stable-isotope labelled internal standards, together with differences in response between glucuronides and aglycones, made quantification problematic. Using HPLC-MS a specific 1-beta-O-AG-related ion at m/z 193 (the glucuronate fragment) was noted enabling selective determination of these isomers. In buffer, transacylation reactions predominated, with relatively little hydrolysis to the free aglycone observed. In human plasma incubations the observed rates of reaction were much faster than for buffer, and hydrolysis to the free aglycone was the major route. These results illustrate the strengths and weaknesses of each analytical approach for this class of analyte.

Light-emitting diode flashlights as effective and inexpensive light sources for fluorescence microscopy.

Light-emitting diodes (LEDs) are becoming more commonly used as light sources for fluorescence microscopy. We describe the adaptation of a commercially available light-emitting diode flashlight for use as a source for fluorescence excitation. This light source is long-lived, inexpensive and is effective for excitation in the range of 440-600 nm.

Bacterial circadian programs.

Twenty years ago, it was widely believed that prokaryotes were too "simple" to have evolved circadian programs. Since that time, however, the cyanobacterial circadian system has progressed from a curiosity to a major model system for analyzing clock phenomena. In addition to globally regulating gene expression, cyanobacteria are one of the only systems in which the adaptive fitness of a circadian system has been rigorously evaluated. Moreover, cyanobacteria are the only clock system in which all essential proteins of the core oscillator have been crystallized and structurally determined, namely, the KaiA, KaiB, and KaiC proteins. A biochemical oscillator can be reconstituted in vitro with these three purified Kai proteins and displays the key properties of temperature-compensated rhythmicity. This result spectacularly demonstrates that a strictly posttranslational clock is sufficient to elaborate circadian phenomena and that a transcription-translation feedback loop is not obligatory. The conjunction of structural information on essential clock proteins with a defined system that reconstitutes circadian oscillations in vitro leads to a turning point whereby biophysical and biochemical approaches bring analyses of circadian clock-work to an unprecedented level of molecular detail.

Chlorine inactivation of spores of Encephalitozoon spp.

This report is an extension of a preliminary investigation on the use of chlorine to inactivate spores of Encephalitozoon intestinalis and to investigate the effect of chlorine on two other species, E cuniculi and E. hellem, associated with human infection. The 50% tissue culture infective doses of these three species were also determined. On the basis of the results obtained, it appears that chlorination of water is an effective means of controlling spores of these organisms in the aquatic environment.

Reconstruction after extirpation of the auricle.

The purpose of this study is to introduce the procedure and results of a combined free flap reconstruction with an external ear prosthesis after tumor extirpation from the lateral side of the head. Over the last 3 years, four patients have undergone total auricle extirpation for varying tumor processes. Each was reconstructed with a radial forearm flap, preserving the external auditory meatus. After primary healing and adjuvant therapy, a prosthetic pinna was applied. Combined use of microsurgical techniques with a prosthetic ear has produced an aesthetically superior result for large soft-tissue defects of the side of the head. This combined technique is able to provide the best aspects of both microsurgical and prosthetic reconstructions for a superior result for the patient.

Circadian programming in cyanobacteria.

Prokaryotic cyanobacteria express robust circadian (daily) rhythms under the control of a timing mechanism that is independent of the cell division cycle. This biological clock orchestrates global regulation of gene expression. Competition experiments demonstrate that fitness is enhanced when the circadian period is consonant with the period of the environmental cycle. Mutational analyses have identified three clock genes in the organism, one of which is related to DNA recombinases and helicases. We propose a new model for the core 'clockwork' that implicates rhythmic changes in the status of the chromosome that underly the rhythms of gene expression.

A clock- and light-regulated gene that links the circadian oscillator to LHCB gene expression.

We have identified and characterized a novel tobacco gene, called ZGT (from the Chinese phrase zhong guang tiaokong, or clock and light controlled), that is regulated by the circadian clock and light. ZGT transcripts have alternate forms that are differentially expressed in different tissues. ZGT is expressed rhythmically in light/dark cycles and in constant light. Constitutive expression of ZGT sustains the expression of the clock-controlled LHCB1*1 gene in constant darkness, when it would normally dampen, but does not affect LHCB1*1 expression in constant light. ZGT expression is induced rapidly by light, and overexpression of ZGT increases the sensitivity of the circadian oscillator to brief light pulses. The ZGT promoter includes a G-box motif that is found in many light-regulated promoters in plants and is the same as the E box described for rhythmically regulated promoters of animal circadian clock genes. The ZGT promoter also includes "evening element" motifs that are correlated with circadian control of plant genes. We postulate that light- and clock-regulated expression of ZGT acts as a coupling agent between the central circadian oscillator and rhythmic LHCB1*1 expression and that it may function as a component in plant phototransduction pathways.

Biomechanics of the first ray. Part III. Consequences of Lapidus arthrodesis on peroneus longus function: a three-dimensional kinematic analysis in a cadaver model.

It has long been proposed that first metatarsocuneiform joint (FMCJ) arthrodesis, also known as Lapidus arthrodesis, can realign the first ray and permanently lock the FMCJ to control hypermobility. Left unanswered is the functional consequence of peroneus longus (PL) after such a procedure. In this study, the effects of PL on the medial column of the foot before and after metatarsocuneiform arthrodesis were evaluated. Seven fresh-frozen cadaver specimens with an intact foot and ankle were mounted on a custom-made acrylic frame and loaded to 400 N while midstance motor function was simulated with pneumatic actuators. Three-dimensional radiowave tracking transducers were attached to the first metatarsal, medial cuneiform, navicular, and talus to measure osseous movements while tensile loads of 0% to 100% of PL predicted force was applied. Simulated arthrodesis of the metatarsocuneiform joint and then additionally the intercuneiform 1-2 joint was achieved with titanium pins and then retested to determine any change in effect from PL. Significant frontal plane eversion of the medial cuneiform (p = .016) and dorsiflexion of the talus (p = .045) occurred after Lapidus arthrodesis was achieved. This suggests that arthrodesis at the first metatarsocuneiform joint increases the efficiency of PL stabilizing action on the medial column.

The fate of free flaps used to reconstruct defects in recurrent head and neck cancers.

The purpose of this study was to assess free-flap viability in patients treated for recurrent head and neck cancers. A 10-year retrospective review identified 121 patients who had had prior head and neck cancers extirpated for cure, who subsequently presented with documented recurrent cancers that were removed, and who then underwent reconstruction with free flaps. The charts of these patients were reviewed for patient demographics, tumor types, location, flaps used for reconstruction, size of area requiring reconstruction, length of operation, previous radiation, and all postoperative morbidity and mortality. The time to recurrence ranged from 21/2 months to 21 years. The majority of tumors treated were squamous cell carcinomas (n = 82). Most of them were located intraorally (n = 75). Radiation therapy had been delivered to 88 patients before their free-flap reconstructions. In this series, 31 percent of all patients required additional surgery for complications, 14 percent of free flaps were lost, and 4 percent of patients died within 30 days of their operation. The significant findings were that a flap that was >4 cm in diameter was related to flap loss (p = 0.03 by the chi2 method) and that flap loss was related to operative times greater than 11 hours (p = 0.03 by the chi2 method). It was concluded that recurrent head and neck cancers with large postextirpation defects that required prolonged operative times yielded a significantly high tendency toward flap failure.

Independence of circadian timing from cell division in cyanobacteria.

In the cyanobacterium Synechococcus elongatus, cell division is regulated by a circadian clock. Deletion of the circadian clock gene, kaiC, abolishes rhythms of gene expression and cell division timing. Overexpression of the ftsZ gene halted cell division but not growth, causing cells to grow as filaments without dividing. The nondividing filamentous cells still exhibited robust circadian rhythms of gene expression. This result indicates that the circadian timing system is independent of rhythmic cell division and, together with other results, suggests that the cyanobacterial circadian system is stable and well sustained under a wide range of intracellular conditions.

Endogenous timekeepers in photosynthetic organisms.

Circadian and photoperiodic timing mechanisms were first described in photosynthetic organisms. These organisms depend upon sunlight for their energy, so adaptation to daily and seasonal fluctuations in light must have generated a strong selective pressure. Studies of the endogenous timekeepers of photosynthetic organisms provide evidence for both a fitness advantage and for selective pressures involved in early evolution of circadian clocks. Photoperiodic timing mechanisms in plants appear to use their circadian timers as the ruler by which the day/night length is measured. As in animals, the overall clock system in plants appears to be complex; the system includes multiple oscillators, several input pathways, and a myriad of outputs. Genes have now been isolated from plants that are likely to encode components of the central clockwork or at least that act very close to the central mechanism. Genetic and biochemical analyses of the central clockwork of a photosynthetic organism are most highly advanced in cyanobacteria, where a cluster of clock genes and interacting factors have been characterized.