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PubMedDate not supplied

Involvement of human small fragment nuclease in the resistance of human cells to UV-C-induced cell death.

Human small fragment nuclease (Sfn) is one of the cellular proteins that were reported to degrade small, single-stranded DNA and RNA. However, the biological role of Sfn in cellular response to various stressors such as UV-C (mainly 254 nm wavelength ultraviolet ray) remains unclear. We have examined whether modulation of human SFN gene expression affects cell survival capacity against UV-C-induced cell death, analyzing colony survival ability in UV-C-sensitive human RSa cells treated with short double-stranded RNA (siRNA) specific for SFN messenger RNA (mRNA). The expression levels of SFN mRNA in the siRNA-treated RSa cells decreased to about 15% compared with those in the control siRNA-treated cells. The siRNA-treated RSa cells showed lower colony survival and higher activity of caspase-3 after UV-C irradiation than the control siRNA-treated RSa cells. Furthermore, the removal capacity of cyclobutane pyrimidine dimers (CPD) in the siRNA-treated RSa cells decreased compared with the control siRNA-treated RSa cells. There was no difference in the colony survival and CPD removal capacity after UV-C irradiation between the control siRNA-treated RSa cells and mock-treated RSa cells. These results suggest that SFN expression is involved in resistance of RSa cells to UV-C-induced cell death through the roles it plays in the DNA repair process.

14-3-3 Proteins↗
PubMedDate not supplied

Pyrimidine (6-4) pyrimidone photoproduct mapping after sublethal UVC doses: nucleotide resolution using terminal transferase-dependent PCR.

UVC irradiation of genomic DNA induces two main types of potentially mutagenic base modifications: cyclobutane pyrimidine dimers (CPDs) and the less frequent (15-30% of CPD levels) pyrimidine (6-4) pyrimidone photoproducts (6-4PP). Ligation-mediated PCR (LMPCR), a genomic sequencing technique, allows CPD mapping at nucleotide resolution following irradiation with sublethal doses of UVB or UVC for most cell types. In contrast, a dose of 80 J/m(2) of UVC that is lethal for the majority of cell types is necessary to map 6-4PP by the LMPCR technique. This compromises the use of LMPCR to study the repair of 6-4PP. To date, no other techniques have been developed to study 6-4PP repair at nucleotide resolution. We have therefore adapted a recently developed technique for the mapping of 6-4PP: terminal transferase-dependent PCR (TDPCR). TDPCR is in many ways similar to LMPCR. This technique is more sensitive and allows the mapping of 6-4PP at UVC doses as low as 10 J/m(2) in genomic DNA and in living cells.

Binding Sites↗
PubMedDate not supplied

Photoreactivation in Paramecium tetraurelia under conditions of various degrees of ozone layer depletion.

Photoreactivation (PR) is an efficient survival mechanism that helps protect cells against the harmful effects of solar-ultraviolet (UV) radiation. The PR mechanism involves photolyase, just one enzyme, and can repair DNA damage, such as cyclobutane-pyrimidine dimers (CPD) induced by near-UV/blue light, a component of sunlight. Although the balance of near-UV/blue light and far-UV light reaching the Earth's surface could be altered by the atmospheric ozone layer's depletion, experiments simulating this environmental change and its possible effects on life have not yet been performed. To quantify the strength of UVB in sunlight reaching the Earth's surface, we measured the number of CPD generated in plasmid DNA after UVB irradiation or exposure to sunlight. To simulate the increase of solar-UV radiation resulting from the ozone layer depletion, Paramecium tetraurelia was exposed to UVB and/or sunlight in clear summer weather. PR recovery after exposure to sunlight was complete at a low dose rate of 0.2 J/m2 x s, but was less efficient when the dose rate was increased by a factor of 2.5 to 0.5 J/m2 x s. It is suggested that solar-UV radiation would not influence the cell growth of P. tetraurelia for the reason of high PR activity even when the ozone concentration was decreased 30% from the present levels.

Animals↗
PubMed2004

Decreased levels of (6-4) photoproduct excision repair in hybrid fish of the genus Xiphophorus.

Selected hybridization in the fish genus Xiphophorus has been used for many years to study the genetics of malignant melanoma. Because DNA damage caused by ultraviolet radiation is implicated in the etiology of sunlight-induced melanoma, the heritability of mechanisms that mitigate DNA damage is a matter of some interest. We examined nucleotide excision repair of the two major types of DNA-damage induced by sunlight; the cyclobutane pyrimidine dimer (CPD) and the pyrimidine(6-4)pyrimidone dimer [(6-4)PD]. In most cases, removal of the (6-4)PD was more rapid than the CPD, and in many cases, the F1 hybrid showed reduced repair efficiency compared with the parental species. These data demonstrate reduced function in multienzyme hybrid systems and provide molecular support for potential reduced fitness in hybrid fish under conditions of environmental stress.

Animals↗
PubMed2002

Contrast sensitivity to radial frequencies modulated by Jn and jn Bessel profiles.

We measured human contrast sensitivity to radial frequencies modulated by cylindrical (Jo) and spherical (jo) Bessel profiles. We also measured responses to profiles of jo, j1, j2, j4, j8, and j16. Functions were measured three times by at least three of eight observers using a forced-choice method. The results conform to our expectations that sensitivity would be higher for cylindrical profiles. We also observed that contrast sensitivity is increased with the j n order for n greater than zero, having distinct orderly effects at the low and high frequency ends. For n = 0, 1, 2, and 4 sensitivity tended to occur around 0.8-1.0 cpd while for n = 8 and 16 it seemed to shift gradually to 0.8-3.0 cpd. We interpret these results as being consistent with the possibility that spatial frequency processing by the human visual system can be defined a priori in terms of polar coordinates and discuss its application to study face perception.

Adult↗
PubMed2006

Detection of genes encoding virulence factors and bacteriocins in fecal enterococci of poultry in Portugal.

Seventy-six Enterococcus isolates (43 E. faecalis, 30 E. faecium, two E. durans, and one E. hirae) recovered from fecal samples of poultry in a slaughterhouse (one isolate per fecal sample and one fecal sample per lot of animals) were studied for bacteriocin production and for the presence of genes encoding bacteriocins and virulence factors. The presence of genes encoding virulence factors (cpd, geE, fsr, ace, agg, and esp) and bacteriocins (entA, entB, entP, entQ, entAS-48, entL50A/B, cyl, and bac31) were studied by polymerase chain reaction in all enterococci. At least two virulence genes were detected in all 43 E. faecalis isolates, cpd and gelE being the most frequently detected genes (97.7%) followed by ace (62.8%), agg (39.5%), fsr (27.9%), and esp (2.3%). No virulence genes were detected in the other enterococcal species with the exception of one E. faecium and one E. durans isolates that harbored the gelE gene. Antimicrobial activity against eight indicator bacteria (including Listeria monocytogenes) was assayed in the enterococci, and 23 (30.3%) showed inhibitory activity against L. monocytogenes, the other 22 enterococci showing activity against indicator bacteria other than L. monocytogenes. Only the entA, entB, and cyl genes were detected in our study (entA + entB in nine E. faecium isolates and the cyl gene in seven E. faecalis isolates). A wide variety of virulence genes have been detected in fecal E. faecalis isolates from poultry, but not in the other enterococcal species. However, the presence of known bacteriocin structural genes is associated more with the E. faecium species.

Animals↗
PubMed1996

Sexual experience of the chronic peritoneal dialysis patient.

The actual and desired frequency of intercourse was studied in 68 randomly selected chronic peritoneal dialysis (CPD) patients. The results were correlated with standard measures of depression (Beck Depression inventory), anxiety (Patient Related Anxiety Scale), physical symptoms (Kupfer-Detre System 2), adequacy of dialysis (KT/Vurea) and nutrition (serum albumin level). In addition, patients assessed their quality of life (PAQOL) using an 1 to 10 analog scale. The mean +/- SD age of all patients studied was 54 +/- 11 yr, the mean dialysis duration was 24 +/- 24 months; 46% of the patients were female, and 34% were diabetic. Sixty-three percent of the patients reported never having intercourse (Group 1), 19% reported having intercourse < or = two times per month (Group II), and 18% reported having intercourse > two times per month (Group III). Dialysis duration, serum albumin level, KT/Vurea, and age were not significantly different among the three groups. Nearly 50% of patients in Group I desired to have intercourse, and 54% of the patients in Group II desired to have intercourse more frequently, Group I patients had significantly higher depression and anxiety scores, more physical symptoms, a poorer overall PAQOL, and less satisfaction with their sexual activity than Group III patients. These results suggest that there is a high prevalence of sexual difficulties in CPD patients. Patients not having intercourse have a poorer quality of life and higher degree of depression and anxiety than patients having intercourse more than two times per month.

Adult↗
PubMed2003

Management of peritonitis in children receiving chronic peritoneal dialysis.

Bacterial peritonitis is a major threat to long-term peritoneal membrane function in pediatric patients receiving chronic peritoneal dialysis (CPD). This review summarizes the demographics, risk factors, and current recommendations regarding diagnostic procedures, management, and prevention of peritonitis in children. Albeit decreasing in incidence, bacterial peritonitis remains a major cause of technique failure in children with endstage renal disease receiving CPD. The use of standardized diagnostic procedures, efficacious antibacterial treatment, and objective response criteria are crucial in improving the outcome of this complication. Current guidelines recommend combining a first- and third-generation cephalosporin for empiric therapy in uncomplicated cases. The initial use of a glycopeptide/third-generation cephalosporin combination should be restricted to patients with risk factors for severe disease, as defined by clinical presentation, young age (<2 years), and recent infection with a methicillin resistant micro-organism. Several risk factors for primary or relapsing peritonitis have been identified, some of which are amenable to preventive measures. These relate to catheter design and implantation technique, connection methodology, early catheter removal in refractory or relapsing peritonitis, and eradication of Staphylococcus aureus from the catheter exit site and/or nasal reservoirs in patients and their caregivers.

Anti-Bacterial Agents↗
PubMed1994

Effects of energy density and protein source on diet digestibility and performance of calves after arrival at the feedlot.

Sixty Angus crossbred steers (initial BW, 237 kg) were used in a 2 x 2 factorial experiment to determine the effects of energy density and protein source in receiving diets on steers performance and total tract nutrient digestion. The factors compared were energy density (1.80 vs 1.48 Mcal/kg of NEm, referred to as high-energy and low-energy, respectively) and protein source (ring-dried blood meal [BM] vs soybean meal [SBM]). Diets containing BM resulted in a 10.6% greater (P < .09) ADG and a 7.6% improvement (P < .05) in efficiency of feed utilization compared with those containing SBM. High-energy diets resulted in an 8.7% improvement (P < .05) in feed efficiency vs low-energy diets. Dry matter digestibility (DMD), NDF digestibility (NDFD), and CP digestibility (CPD) were exceptionally high during wk 1, when DMI was approximately 1.5 kg/d. Nutrient digestibility declined during wk 2 and 3, as intake increased, before stabilizing between wk 4 and 6. Additionally, NDFD was not consistently lower (P > .10) during this study for high-energy diets than for low-energy diets. The results of the overall performance data indicate that, compared to SBM, feeding BM may improve ADG and feed efficiency during the receiving period when dietary CP is approximately 13%. Additionally, DMD, NDFD, and CPD were higher on d 7 than at any other time, indicating that by d 7 ruminal function was not adversely affected. Therefore, it seems that the reduced feed intake and growth rate normally seen during the first 2 wk in the feedlot is not caused by a reduction in diet digestibility.

Animal Feed↗
PubMed1995

Visual evoked potentials generator model derived from different spatial frequency stimuli of visual field regions and magnetic resonance imaging coordinates of V1, V2, V3 areas in man.

Visual evoked potentials (VEPs) to pattern reversal vertical bar stimuli were recorded from 24 scalp derivations (including zygomatic and inion) referenced to digitally linked earlobes in 50 controls. 1, 2 and 4 cpd patterns were presented as full field (FF) stimuli, on Upper Hemifields (UHF) and Lower Hemifields (LHF), upper and lower quadrants and with the occlusion of central and peripheral UHF and LHF. VEPs to octant stimuli were also recorded with 2 cpd patterns. N1, P1 and N2 components were recorded from posterior and inion derivations with FF stimuli, from posterior derivations with LHF stimuli, only from inion leads with UHF stimuli, from derivations ipsilateral to stimuli with quadrants and octants, and consistently from midline derivations only with lower quadrants. Polarity inverted sequences (iN1-iP1-iN2) were recorded from the other scalp derivations, with similar latency and spatial frequency sensitivity as N1-P1-N2. Single Equivalent Dipole (ED) calculations were performed on N1 and P1 recorded in the different stimulus conditions. Our findings contradict previous hypotheses on VEP generators and contradict the predictions of VEPs polarity and distribution based on the "cruciform model" of VEPs generators. In order to explain the distribution of VEPs to upper and lower half fields and to quadrant and octants, we propose a model based on the position of the medial and occipito-polar surface of visual cortex in man.

Adult↗
PubMed1986

The effect of refractive error on pattern electroretinograms in primates.

The effect of optical blur on the steady-state (6, 8, 10 Hz) counterphase pattern electroretinogram (PERG) was measured in three normal cynomolgus monkeys. Blur was induced using lenses of -8.00 to +12.00 diopters, and monocular PERGs were recorded at a viewing distance of 0.32 meters. A substantial decrease in PERG amplitude occurred with a 0.51 cpd grating when +4.00 diopters of blur or greater were used. PERG amplitude to a 1.25 cpd grating decreased with lenses greater than +2.00 diopters. Minus lenses caused a steep decline in PERG amplitude of both spatial frequency gratings. These results indicate that refractive state has a significant effect upon the PERG and should be carefully considered in electrophysiologic testing of the primate visual system.

Accommodation, Ocular↗
PubMed1987

Additive solutions for better blood preservation.

For several decades the standard blood preservative solution consisted of citrate, dextrose, and, later, phosphate (ACD and CPD). In 1978 a new solution containing adenine (CPDA-1) was introduced to permit extension of red cell shelf life from 21 to 35 days. The success of CPDA-1 and the high percentage of blood units processed into components (estimated 87% in 1983) have stimulated a burst of research and development activity to develop improved red cell preservation systems. Most of these systems have taken the form of "additive solutions" in which the blood is drawn in CPD or CP2D and processed into components. Then the packed red cells are stored by addition of a solution customized for their preservation. This review evaluates these additive solutions in detail. Innovative systems for pH control (buffers and resins) have also been explored. Our review concludes with discussion of the safety aspects of new preservative solutions and the methodological problems of evaluating these solutions.

Blood Preservation↗
PubMed1993

The relationship between the location of the breakpoint within the M-bcr and clinical parameters.

The Philadelphia chromosome (t9;22)(q34;q11) is a characteristic abnormality in chronic myeloid leukemia. In greater than 95% of the cases, the breakpoint occurs with the M-bcr region of the BCR gene on chromosome 22. Several studies have attempted to correlate the location of the breakpoint within the M-bcr with a clinical parameter. The majority of studies have examined the relationship between the site of breakpoint and the median chronic phase duration (CPD). Some studies have reported a correlation, with 5' breakpoint patients who have a longer median CPD than patients with a 3' breakpoint. However, other groups have reported that no correlation exists. Furthermore, data from some of the latter groups have suggested that a correlation may exist with the lineage of blast crisis which developed and 3' breakpoint patients had a higher than expected number of lymphoid blast crisis. A correlation between high platelet counts at diagnosis and patients with a 3' breakpoint or those who expressed a b3-a2 BCR-ABL mRNA has also been described. No consistent conclusion from any of these studies can be drawn. This may due, in part, to some degree of patient and sample selection, although environmental, genetic or life-style factors may also contribute.

Biomarkers, Tumor↗
PubMedDate not supplied

Assessment of visual acuity in children with trisomy 18.

Although 90% of children with trisomy 18 (Edwards syndrome) die in the first year of life, a small proportion survive into the second and third decade. Many do not have associated ocular abnormalities that might affect vision. Measurable visual acuity has not been reported in these profoundly developmentally delayed individuals. Five children with trisomy 18, aged six months to eight years, underwent complete eye examination including assessment of binocular grating acuity with Teller acuity cards and assessment of binocular vernier acuity with vernier cards. All children were nonverbal with profound developmental delay. Binocular grating acuity ranged from 0.9 cycles per degree (cpd) to 2.2 cpd. This represents a reduction of 1.9 to 5.1 octaves (mean 3.5 octaves, SD 1.3 octaves) compared to age matched norms. None of the children responded to any of the vernier offsets, including the largest of 64 minutes of arc. All children with trisomy 18 demonstrated a measurable grating acuity that was well below normal for age, consistent with profound developmental delay.

Child↗
PubMed2004

Reflections upon the trends of education and research in small animal reproduction in Europe.

An open questionnaire-based survey was performed among 86 institutions of veterinary education in 32 European countries: 15 within the European Union (EU) and 17 outside the EU, in Central and Eastern Europe and the European Free Trade Association (EFTA). The survey aimed to provide a view of the general status of education and research in small animal reproduction (SAR) in Europe. It further aimed to disclose whether ongoing trends in organization (e.g., from the classical animal reproduction discipline orientation [DO] toward a species-oriented [SO] organization) among veterinary colleges responsible for undergraduate education and research in SAR have affected the provision of clinical services, continuing professional development (CPD), specialization, post-graduate education, and research. Response rates reached 80% among EU institutions and 48.4% in other countries (overall response rate = 68.6%). A clear, significant majority of institutions (> 60%) were DO, with a well-defined comparative subject in the veterinary curriculum. No differences were reported for either orientation in their ability to provide undergraduate education or clinical services in SAR. However, more DO institutions reported active research in SAR than their SO counterparts. Similar (and stronger) differences were seen for post-graduate education, CPD, and participation in specialization programs (national or European). Finally, more DO than SO institutions provided assisted reproductive technologies (ARTs), such as AI with frozen semen, to customers. The analysis of the data emanating from the respondents' perceptions, supports the advantages of the more classical, DO-based approach. The results highlight the need for caution when institutions abandon the comparative benefits of the classical DO animal reproduction subject for a SO approach, which tends to prioritize clinical specialized service rather than research and research education. In the author's opinion, in the absence of the data generated by comparative research and used in research education and the development of new technologies in SAR, there is a risk that sound science-based academic preparation for undergraduates and candidates for post-graduate research education is constrained. To counteract these negative trends, SAR must be recognized as a very important branch of the department of animal reproduction. Access to resources, personnel for teaching and research, and curriculum space should be made available in order to provide the basis for relevant post-graduate training, specialization, and research.

Animals↗
PubMed1992

Spatial-frequency-contingent color aftereffects: adaptation with one-dimensional stimuli.

The McCollough effect was shown to be spatial-frequency selective by Lovegrove and Over (1972) after adaptation with vertical colored square-wave gratings separated by 1 octave. Adaptation with slide-presented red and green vertical square-wave gratings separated by 1 octave failed to produce contingent color aftereffects (CAEs). However, when each of these gratings was adapted alone, strong CAEs were produced. Adaptation with vertical colored sine-wave gratings separated by 1 octave also failed to produce CAEs, but strong effects were produced by adaptation with each grating alone. By varying the spatial frequency of the test sine wave, CAEs were found to be tuned for spatial frequency at 2.85 octaves after adaptation of 4 cycles per degree (cpd) and at 2.30 octaves after adaptation of 8 cpd. Adaptation of both vertical and horizontal sine-wave gratings produced strong CAEs, with bandwidths ranging from 1.96 to 2.90 octaves and with lower adapting contrast producing weaker CAEs. These results indicate that the McCollough effect is more broadly tuned for spatial frequency than are simple adaptation effects.

Adaptation, Ocular↗
PubMed1992

Spatial-frequency-contingent color aftereffects: adaptation with two-dimensional stimulus patterns.

The spatial-frequency theory of vision has been supported by adaptation studies using checkerboards in which contingent color aftereffects (CAEs) were produced at fundamental frequencies oriented at 45 degrees to the edges. A replication of this study failed to produce CAEs at the orientation of either the edges or the fundamentals. Using a computer-generated display, no CAEs were produced by adaptation of a square or an oblique checkerboard. But when one type of checkerboard (4 cpd) was adapted alone, CAEs were produced on the adapted checkerboard and on sine-wave gratings aligned with the fundamental and third harmonics of the checkerboard spectrum. Adaptation of a coarser checkerboard (0.80 cpd) produced CAEs aligned with both the edges and the harmonic frequencies. With checkerboards of both frequencies, CAEs were also found on the other type of checkerboard that had not been adapted. This observation raises problems for any edge-detector theory of vision, because there was no adaptation to edges. It was concluded that spatial-frequency mechanisms are operating at both low- and high-spatial frequencies and that an edge mechanism is operative at lower frequencies. The implications of these results are assessed for other theories of spatial vision.

Adaptation, Ocular↗
PubMedDate not supplied

Correlation of wavefront data and corneal asphericity with contrast sensitivity after laser in situ keratomileusis for myopia.

PURPOSE: To investigate the relationship between contrast sensitivity (CS), Zernike wavefront aberrations (WFA), and asphericity after laser in situ keratomileusis (LASIK) for myopia. METHODS: LASIK was performed using the Nidek EC-5000 excimer laser with custom aspheric transition zone (CATz) ablations. Total and high order (HO) WFA of 71 eyes (37 patients) undergoing LASIK in March 2003 were measured before and at 1 month postoperatively with the Nidek OPD-Scan aberrometer at a 4-mm pupil entrance; asphericity was measured at 6 mm (Q index). Preoperative and 1 to 3-month postoperative contrast sensitivity were evaluated with the Vector Vision CSV-1000 at 3, 6, 12, and 18 CPD; the Area Under the Log Contrast Sensitivity Function (AULCSF) was calculated. Uncorrected-visual acuity (UCVA) was evaluated. RESULTS: One month after LASIK, CS decreased significantly at 6 CPD and above (P<.05), then returned to normal at 3 months (P=.33). Postoperative AULCSF correlated with patient age (P=.04) but not with total WFA (P=.13), HO WFA (P=.50), or asphericity (P=.22). Postoperative Logmar UCVA correlated with postoperative total and HO WFA (P<.05). Postoperative total WFA correlated with spherical equivalent refraction (P<.0001); HO WFA correlated with Strehl ratio (P=.004) and asphericity (P=.03). The HO WFA increase was 0.065 microm (P<.05) and did not correlate with preoperative refraction (P=.40). Increase in asphericity correlated with corneal refractive change and was predicted by the parabolic Munnerlyn equation (P<.0001). CONCLUSIONS: After LASIK, AULCSF was not dependent on WFA, but mainly on patient age. WFA results correlated well with postoperative spherical equivalent refraction, asphericity, and Strehl ratio. These conclusions support a published hypothesis that postoperative low amount of WFA does not completely fit contrast sensitivity measurements.

Adult↗