Unrepairable DNA double-strand breaks initiate cytotoxicity with HSV-TK/ganciclovir.

The herpes simplex virus thymidine kinase (HSV-TK) is the most widely used suicide gene in cancer gene therapy due to its superior anticancer activity with ganciclovir (GCV) compared with other HSV-TK substrates, such as 1-ß-D-arabinofuranosyl thymine (araT). We have evaluated the role of DNA damage as a mechanism for the superiority of GCV. Using γ-H2AX foci as an indicator of DNA damage, GCV induced ≥ sevenfold more foci than araT at similar cytotoxic concentrations. The number of foci decreased after removal of either drug, followed by an increase in Rad51 foci indicating that homologous recombination repair (HRR) was used to repair this damage. Notably, only GCV produced a late and persistent increase in γ-H2AX foci demonstrating the induction of unrepairable DNA damage. Both drugs induced the ATR damage response pathway, as evidenced by Chk1 activation. However, GCV resulted in greater activation of ATM, which coincided with the late induction of γ-H2AX foci, demonstrating the presence of DNA double-strand breaks (DSBs). The increase in DSBs after Rad51 induction suggested that they occurred as a result of a failed attempt at HRR. These data demonstrate that the late and unrepairable DSBs observed uniquely with GCV account for its superior cytotoxicity and further suggest that inhibition of HRR will enhance cytotoxicity with HSV-TK/GCV.

Competition intensity at local versus regional spatial scales.

Studies of competition intensity over natural (i.e. topographic) gradients often contradict the results from studies where artificial (i.e. fertilizer) gradients have been used. Why should the type of gradient matter? To explore the possibilities, we performed experiments to measure competition intensity experienced by tree seedlings from grass competitors across a natural resource gradient, and simultaneously across artificial soil nutrient (fertiliser) gradients. We measured various functional traits (i.e. specific leaf area, leaf area, leaf nitrogen content, delta(15)N, delta(13)C, RGR) to gain mechanistic insight into the nature of competition across these gradients. Competition intensity increased with increasing resource availability, unequivocally at the local scale (i.e. with fertilizer application) but not at the regional scale (i.e. across the natural productivity gradient). Our measurements of plant traits were generally consistent with measurements of competition intensity, and demonstrate that competition occurs even when resource levels are low. Competition mainly acted to reduce the growth of Eucalyptus seedlings. Functional (physiological) traits in the Eucalyptus seedlings were not strongly affected by competitors, with the possible exception of delta(15)N, which may effectively integrate information on soil nutrient, moisture and leaf processes.

Population based epidemiology and prognosis of mesothelioma in Leeds, UK.

INTRODUCTION: Malignant mesothelioma is a fatal neoplasm, which is rapidly increasing in incidence throughout Western Europe. To date there have been no studies reporting on the natural history and interventional practices on a comprehensive unselected population, as opposed to reports from referral institutions or compensation claimants. We present a population based study capturing data on all patients with mesothelioma presenting within a defined geographical area over a 4 year period in the UK. METHOD: Data of all cases occurring in Leeds with a population of 750 000 were collected retrospectively from 2002 to 2003 and prospectively from 2004 to 2005. All patients' hospital records and the Trust histology database were reviewed, as well as coroner's reports on all patients with a post mortem diagnosis of mesothelioma. RESULTS: Over the 4 year study period, there were a total of 146 cases in Leeds; 77% were male. Median age was 74 years (range 36-93). Median survival from diagnosis was 8.9 months. 92% and 8% had histological or cytological confirmation, respectively. 85% had documented evidence of definite or probable exposure to asbestos. 110/146 (75%) had symptomatic pleural effusions at presentation. Twice the number of patients (42 vs 17) were managed with surgical rather than bedside pleurodesis and these had a lower recurrence rate (14% vs 47%; p = 0.02). 122 patients had video assisted thoracoscopic surgery/cutting CT biopsies or chest drains. 73/122 (60%) had prophylactic radiotherapy to these sites. There were seven cases (5%) of tract invasion by tumour and six of these had received prophylactic radiotherapy. Median time to seeding was 174 days. 92/146 (63%) had a performance status of 2 or better at diagnosis but only 54/146 were considered fit for chemotherapy. Of these, 28 (52%) declined chemotherapy; the overall uptake of chemotherapy or entry into a trial was 18%. No patient had radical surgery. CONCLUSION: This comprehensive population based audit has shown that the median age at presentation of malignant mesothelioma is increasing and baseline performance status and survival is worse than in selected series. 37% of patients were considered suitable for palliative chemotherapy but less than 20% accepted this offer. Thorascopic pleurodesis appears to be associated with fewer recurrences. The role of prophylactic radiotherapy to chest drain and biopsy sites needs reappraisal.

Exposure to Altered Gravity During Specific Developmental Periods Differentially Affects Growth, Development, the Cerebellum and Motor Functions in Male and Female Rats.

We previously reported that perinatal exposure to hypergravity affects cerebellar structure and motor coordination in rat neonates. In the present study, we explored the hypothesis that neonatal cerebellar structure and motor coordination may be particularly vulnerable to the effects of hypergravity during specific developmental stages. To test this hypothesis, we compared neurodevelopment, motor behavior and cerebellar structure in rat neonates exposed to 1.65 G on a 24-ft centrifuge during discrete periods of time: the 2(nd) week of pregnancy [gestational day (G) 8 through G15; group A], the 3(rd) week of pregnancy (G15 through birth on G22/G23; group B), the 1(st) week of nursing [birth through postnatal day (P) 6; group C], the 2(nd) and 3(rd) weeks of nursing (P6 through P21; group D), the combined 2(nd) and 3(rd) weeks of pregnancy and nursing (G8 through P21; group E) and stationary control (SC) neonates (group F). Prenatal exposure to hypergravity resulted in intrauterine growth retardation as reflected by a decrease in the number of pups in a litter and lower average mass at birth. Exposure to hypergravity immediately after birth impaired the righting response on P3, while the startle response in both males and females was most affected by exposure during the 2(nd) and 3(rd) weeks after birth. Hypergravity exposure also impaired motor functions, as evidenced by poorer performance on a rotarod; while both males and females exposed to hypergravity during the 2(nd) and 3(rd) weeks after birth performed poorly on P21, male neonates were most dramatically affected by exposure to hypergravity during the second week of gestation, when the duration of their recorded stay on the rotarod was one half that of SC males. Cerebellar mass was most reduced by later postnatal exposure. Thus, for the developing rat cerebellum, the postnatal period that overlaps the brain growth spurt is the most vulnerable to hypergravity. However, male motor behavior is also affected by midpregnancy exposure to hypergravity, suggesting discrete and sexually dimorphic windows of vulnerability of the developing central nervous system to environmental perturbations.

Sexual dimorphism in cerebellar structure, function, and response to environmental perturbations.

Sexual dimorphism of CNS structure and function has been observed in humans and animals, but remains relatively unrecognized in the context of the cerebellum. Recent research in our laboratory has examined whether these gender differences extend to cerebellar structure and function, as well as the impact of environmental factors on the developing cerebellum. Perinatal exposure to both chemical and physical perturbations in the environment (in our experiments, PCBs or hypergravity) affects growth, neurodevelopment, and motor coordination differently in males and females. These neurodevelopmental and behavioral effects are accompanied by sex-related changes in cerebellar mass and cerebellar protein expression. Exposure to chemical toxins (PCBs) resulted in more dramatic neurodevelopmental and behavioral changes in male neonates. It is possible that gender-related differences in male and female cerebellar structure and function are related to sex-specific development of the cerebellum and sex-specific distribution of specific receptors, local synthesis of trophic factors, and maturation of the pituitary hypophesial axis. These sex-related differences may underlie the sex-specific preponderance of certain neuropsychiatric disorders, and must be incorporated in the design of future basic and clinical investigations.

Photodynamic therapy with verteporfin for choroidal neovascularization in patients with diabetic retinopathy.

PURPOSE: To report the use of photodynamic therapy (PDT) with verteporfin in three patients with choroidal neovascularization (CNV) from age-related macular degeneration and underlying diabetic retinopathy. The level of diabetic retinopathy would have excluded these patients from participation in previously reported randomized clinical trials evaluating PDT with verteporfin due to a theoretic concern of damage to the overlying retinal vasculature. DESIGN: Retrospective interventional case series. METHODS: Three patients from a referral practice with at least severe nonproliferative diabetic retinopathy and a history of clinically significant macular edema developed loss of vision from concurrent choroidal neovascularization evaluated with fundus photography and fluorescein angiography before and after PDT with verteporfin to identify adverse retinal vascular events. RESULTS: Four eyes in three patients had PDT using verteporfin. Three eyes received two treatments. With short follow-up, visual acuity remained stable in two eyes, improved from 20/400 to 20/320 in one eye, and decreased from 20/200 to 20/400 in one eye. Fluorescein angiograms at intervals from 2 weeks to 3 months after PDT showed no damage to the retinal vasculature or progression of the diabetic retinopathy, but did show a decreased area of fluorescein leakage from CNV. One eye that had new subretinal hemorrhage following treatment appeared to show new vasculopathy on initial evaluation of the post-treatment angiogram. Retrospective review suggested that the subretinal hemorrhage provided increased contrast to more easily visualize vasculopathy that was present before the PDT. CONCLUSIONS: Three patients with diabetic retinopathy undergoing a total of seven PDT treatments with verteporfin in four eyes had no new retinal vascular abnormalities develop. No other atypical responses of CNV to PDT were noted except new subretinal hemorrhage, providing increased contrast of the overlying vasculature, which gave the false impression of the development of new vasculopathy in one eye. Patients with diabetic retinopathy who have concurrent CNV for which PDT with verteporfin is recommended should be cautioned regarding the theoretical concerns of harming the retinal vasculature. Periodic surveillance for such concerns seems warranted until more experience is obtained.

Chronicity and instability of children's peer victimization experiences as predictors of loneliness and social satisfaction trajectories.

The present investigation was conducted to predict children's loneliness and social satisfaction growth curves from changes in their peer victimization status. Toward this aim, 388 children (193 boys, 195 girls) were interviewed at five points: as children entered kindergarten (in the fall) and spring of kindergarten through third grade. At each assessment, data were gathered on the frequency of children's peer victimization and degree of loneliness and social satisfaction. Groups were formed on the basis of timing and duration of children's victimization status. Hierarchical linear modeling was used to test several hypotheses regarding the nature of victimized children's growth curves. For instance, consistent with the Onset Hypothesis, the trajectories that emerged for children who moved from nonvictim to victim classification showed increasing levels of loneliness and decreasing social satisfaction. In contrast, findings for the Cessation Hypothesis were mixed, which suggests that children moving from victim to nonvictim status do not necessarily evidence significant improvements in loneliness or social satisfaction. The somewhat disparate trajectories that emerged for loneliness and social satisfaction are discussed.

Information visualization and analytical data mining in pharmaceutical R&D.

We review the recent literature in the area of data mining in large-scale databases, especially as applied by informatics professionals in pharmaceutical R&D. We focus on the combined use of analytical and visual approaches to data mining. Analytical methods result in simplified representations of data and facilitate understanding. Visual data mining approaches are a natural and necessary complement to the application of numerical methods, as they facilitate comprehension of data at any level. The combined use of visual and analytical methods is especially important for extracting information from large, complex datasets. That this is the case can be seen from the recent burgeoning use of information visualization in the pharmaceutical R&D literature, this coming after a decade-long 'ramp up' in the volume of data generated as a result of recent technological changes in the way research is conducted.

Parenting behaviors and parent-child relationships: correlates of peer victimization in kindergarten?

This study examined features of parenting behavior and the parent-child relationship as correlates of peer victimization in young children. A sample of 197 kindergartners (94 girls and 103 boys) and their primary caregivers were videotaped in their homes while engaging in multiple interactional tasks, and peer victimization data were gathered on children as they began kindergarten. The video-recorded interaction data were used to create measures of parenting behavior (e.g., intrusive demandingness, responsiveness) and relationship quality (i.e., intense closeness), which were examined as predictors of peer victimization. High intrusive demandingness and low responsiveness were associated with peer victimization in both boys and girls, and parent-child relationships characterized by intense closeness were associated with higher levels of peer victimization in boys. Results are discussed in terms of the role that caregiver socialization plays in the development of child behaviors that may increase children's risk for peer victimization.

Central nervous system nitric oxide synthase activity regulates insulin secretion and insulin action.

Systemic inhibition of nitric oxide synthase (NOS) with NG-monomethyl-L-arginine (L-NMMA) causes acute insulin resistance (IR), but the mechanism is unknown. We tested whether L-NMMA-induced IR occurs via NOS blockade in the central nervous system (CNS). Six groups of Sprague-Dawley rats were studied after chronic implantation of an intracerebroventricular (ICV) catheter into the lateral ventricle and catheters into the carotid artery and jugular vein. Animals were studied after overnight food deprivation, awake, unrestrained, and unstressed; all ICV infusion of L-NMMA or D-NMMA (control) were performed with artificial cerebrospinal fluid. ICV administration of L-NMMA resulted in a 30% rise in the basal glucose level after 2 h, while ICV D-NMMA had no effect on glucose levels. Insulin, epinephrine, and norepinephrine levels were unchanged from baseline in both groups. Tracer (3H-3-glucose)-determined glucose disposal rates during 2 h euglycemic hyperinsulinemic (300 microU/ml) clamps performed after ICV administration of L-NMMA were reduced by 22% compared with D-NMMA. Insulin secretory responses to a hyperglycemic clamp and to a superimposed arginine bolus were reduced by 28% in L-NMMA-infused rats compared with D-NMMA. In conclusion, ICV administration of L-NMMA causes hyperglycemia via the induction of defects in insulin secretion and insulin action, thus recapitulating abnormalities observed in type 2 diabetes. The data suggest the novel concept that central NOS-dependent pathways may control peripheral insulin action and secretion. This control is not likely to be mediated via adrenergic mechanisms and could occur via nonadrenergic, noncholinergic nitrergic neural and/or endocrine pathways. These data support previously published data suggesting that CNS mechanisms may be involved in the pathogenesis of some forms of insulin resistance and type 2 diabetes independent of adiposity.

Inhibition of preretinal and optic nerve head neovascularization in pigs by intravitreal triamcinolone acetonide.

PURPOSE: The authors tested the antiangiogenic properties of intravitreally administered triamcionolone acetonide in a pig model of preretinal neovascularization to determine the effectiveness of this therapy in preventing neovascularization. METHODS: In 14 eyes of seven pigs, branch retinal vein occlusions were created in a standardized manner using photodynamic thrombosis with rose bengal dye and thermal burns from the argon green laser. Intravitreal injection of approximately 4 mg of triamcinolone acetonide was performed in one eye of each animal, and eyes were followed clinically for 12 weeks with ophthalmoscopy and fundus photography. A standardized grading system was developed to permit masked assessment of disc proliferations from fundus stereophotographs. After death, all neovascularization was confirmed histopathologically and a final grade was assigned to each eye. Statistical analysis employed use of a nonparametric test of the paired data. RESULTS: Significant inhibition of neovascularization was observed in triamcinolone-treated eyes (P = 0.0156). Although none of the steroid-injected eyes demonstrated clinically evident new vessels, histopathologic and photographic analysis results demonstrated fine new vessels on the optic disc in four eyes. In all of the untreated eyes, neovascularization of a moderate (II) to high (III to IV) grade developed. CONCLUSIONS: Intravitreal triamcinolone acetonide effectively inhibited preretinal and optic nerve head neovascularization in the pig model. The grading system used permitted masked assessment of outcome and paired analysis allowed a conclusion to be drawn from a relatively small number of eyes. The mechanisms by which triamcinolone acetonide inhibits neovascularization remain to be elucidated.

Melanocytes and iris color. Electron microscopic findings.

OBJECTIVE: To quantitatively associate iris color with melanocyte pigment content. METHODS: Autopsy eyes were classified as uniform-blue, uniform-hazel, or uniform-brown or showing a darker peripupillary ring. Using electron microscopic images and computerized image analysis, area, number, and size of mature melanosomes within the perinuclear cytoplasmic area only or within perinuclear and peripheral cytoplasmic areas of the superficial stromal melanocytes combined were measured. RESULTS: Average melanosomal area per perinuclear cytoplasmic area (AMAC) and average number of melanosomes per perinuclear area (AMNC) significantly differed across iris color groups (overall P<.001). This result reflects the large difference between blue-uniform and all other color groups. A marginally significant (nominal) trend from blue-ring through brown-ring was also detected (P=.06 for AMAC and P=.07 for AMNC). The average perinuclear cytoplasmic area was larger in the central iris zone (within 1 mm around the pupillary margin) than in the intermediate iris zone (between 1 and 2 mm around the pupillary margin) (P=.002), but AMAC and AMNC did not significantly differ between zones. The average melanosome size did not differ significantly across color groups (P=.11). CONCLUSION: Differences in iris colors are at least partially attributed to variable AMNC and AMAC within superficial melanocytes.

Sibling incest aversion as an index of oedipal conflict.

This study examines sibling incest aversion as an index of the Oedipus complex. The scale's construction and its relation to presence of opposite sex siblings, guilt, and neuroticism is described. Males displayed less aversion and more variability in incest aversion than did females. There was a positive relation between aversion and having an opposite sex sibling for males, but not for females. For both sexes there was a positive relation between sex guilt and aversion. Compared to high or low incest aversion females, middle females displayed a mild obsessive-compulsive pattern, higher hostility guilt, more neurotic complaints, less extraversion and more sensitization. The high reliability and significant relations with relevant variables demonstrate the usefulness of this scale.