Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “CPD”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 901 records · Page 50Linked to original sources
PubMed1989

[Comparison of five modes of dialysis in neurosurgical patients with renal failure].

In neurosurgical patients with renal failure, dialysis entails specific problems, chief of which is increased intracranial pressure and progressive brain edema as a result of rapid lowering of the serum osmolality. Another major problem is a tendency to hemorrhage, in response to either systemic heparinization or insufficient dialysis. The authors describe the results obtained with hemodialysis (HD), continuous arteriovenous hemofiltration (CAVH), continuous ambulatory peritoneal dialysis (CAPD), continuous peritoneal dialysis (CPD), and intermittent peritoneal dialysis (IPD). Nine patients were treated with HD, one with CAVH, five with CAPD or CPD, and two with IPD. Three of the six patients treated with continuous dialysis (CAVH, CAPD, and CPD) died, whereas intermittent dialysis (HD and IPD) carried an 82% mortality rate (nine of 11 patients). The causes of death were progressive brain edema in three cases, intracranial hemorrhage in three, gastrointestinal bleeding in three, overhydration due to insufficient dialysis in one, septicemia in one, and rupture of a cerebral aneurysm in one. Continuous dialysis appeared to be superior to intermittent dialysis in these neurosurgical patients in that it produced less brain edema and was less often associated with hemorrhage due to insufficient dialysis. In HD and CAVH, systemic heparinization was also thought to account for the high incidence of hemorrhage. However, CAVH with short half-life anticoagulants may be useful in patients who have abdominal complications and are therefore not suitable candidates for peritoneal dialysis.

Adult↗
PubMed1990

Quantity and characteristics of microorganisms associated with ruminal fluid or particles.

An experiment was conducted to 1) determine quantity of microbial CP and DM associated with undigested feed particles, 2) quantify the amount of microorganisms removed from ruminally incubated forages and 3) compare forage disappearances (D) corrected for microbial contamination, using diaminopimelic acid (DAPA) ratios obtained from particle-associated or fluid-associated microorganisms. Samples of alfalfa hay, bermudagrass hay and orchardgrass hay placed in dacron bags were incubated via ruminal cannula for 6 and 12 h. Whole ruminal contents (WRC) were sampled at the time of bag removal and partitioned into fluid- and particle-associated microorganisms. Particle-associated microorganisms were further divided into loosely-associated (LA) and firmly associated (FA) microorganisms. Percentage microbial CP and DAPA, quantities of OM, CP (mg) and DAPA (micrograms), microbial contamination and microbial contribution to ruminal contents were not affected by time (P greater than .05). The highest concentrations of CP and DAPA were found in fluid and LA, respectively (P less than .01). The total amount (content) of OM, CP and DAPA were highest in FA and lowest in microbes in the fluid fraction. Firmly-associated microorganisms constituted 54.1% of the particle-associated population. Corrected DMD were higher (P less than .01) based on FA than on fluid and LA microbe compositions. Corrected CPD were similar (P greater than .10) between populations except at 6 h, when LA corrected CPD were lower. Theoretically, using FA microorganisms should give the most accurate correction for microbial contamination. However, results indicate that, although the three populations differed in composition, fluid and FA corrected CPD were similar. Corrections based on composition of any of these three populations will yield higher estimates of disappearance compared with uncorrected values.

Animal Feed↗
PubMed2001

Clostridial antibody response from injection-site lesions in beef cattle, long-term response to single or multiple doses, and response in newborn beef calves.

Experiments were conducted to compare clostridial antibody response of beef heifers that do and do not develop injection-site lesions, evaluate long-term antibody response of a single- and multiple-dose toxoid, and evaluate the ability of a clostridial toxoid to elicit an active antibody response in newborn calves. In Exp. 1, 37 weaned heifers were vaccinated (d 0) with a clostridial vaccine (Alpha-7, 2 mL, s.c.). Serum samples were collected on d 0, 28, 56, 84, and 112 to determine clostridial antibody titers. On d 28, heifers were visually inspected and palpated for injection-site lesions. The percentage of heifers that developed lesions was 64.9%. Lesioned heifers had elevated antibody titers for Clostridium chauvoei (CC) on d 28 (P < 0.08) and 84 (P < 0.07) compared with non-lesioned heifers. Clostridium sordellii (CS) and perfringens type D (CPD) antibody titers were greater in lesioned heifers than in non-lesioned heifers on d 28 and 56. In Exp. 2, long-term antibody response of Alpha-7 (A7) and Ultrabac 7 (UB7) was investigated in stocker heifers. The A7 heifers (n = 15) received one 2-mL vaccination (d 0), and the UB7 heifers (n = 15) received a 5-mL vaccination on d 0 and 28. Blood samples were collected on d 0, 28, 56, 84, 112, 140, and 180. Clostridium chauvoei, CPD, and Cl. novyi (CN) antibody titers from the A7 heifers were greater than those from the UB7 heifers on d 28. Due to the second UB7 injection, CC, CS, CN, and Cl. perfringens type C (CPC) antibody titers were greater in UB7 heifers than in A7 heifers on d 56. By d 112, titers were not different, and by d 140 all antibody titers were below detectable levels. In Exp. 3, 58 pregnant, mature, crossbred cows were vaccinated with A7 before calving. At birth, calves were carefully observed to ensure consumption of colostrum. Calves were blocked according to parturition date, and calves in each block were randomly allocated to receive A7 (s.c. at 3 +/- 3 d of age) or remain unvaccinated controls. Calves were bled at the time of vaccination (d 0) and on d 28, 56, 84, and 112. Antibody titers for CC, CPC, and CPD were elevated on d 0 and decreased throughout the experimental period (P < 0.01), but no titer differences (P > 0.10) were detected between treatment groups on any of the days sampled. These data indicated that antibody titers against clostridial diseases are enhanced when injection-site lesions develop. One injection of Alpha-7 seemed to provide the same length of protection as two injections of Ultrabac 7.

Animal Husbandry↗
PubMed1998

Relationship between contrast sensitivity and metabolic control in diabetics with and without retinopathy.

Contrast sensitivity was studied in diabetic adolescents and young adults with and without retinopathy in order to evaluate their central vision, to analyze the relationship of metabolic control to the presence and severity of retinopathy, and to re-evaluate the response to this test after a significant improvement in metabolic control. Twenty adolescent and young adult diabetics without retinopathy and 40 diabetics with retinopathy of varying degree were enrolled in the study; 20 healthy age and sex-matched subjects served as controls. Contrast sensitivity was assessed with a CSV-1000 contrast testing instrument, testing for four spatial frequencies, 3, 6, 12 and 18 cycles per degree (cpd). Diabetics with no retinopathy showed a weak but significant difference at 18 cpd compared with controls (P = 0.04), while diabetics with background retinopathy showed a significant reduction of contrast sensitivity at 12 and 18 cpd when compared with controls (P < 0.001). In patients with preproliferative/proliferative retinopathy a highly significant reduction of contrast sensitivity at all frequencies was found compared with controls. Furthermore, these patients had a significantly lower mean contrast sensitivity than patients without retinopathy. The patients were re-evaluated after a significant amelioration of metabolic control. An improvement in contrast sensitivity was found in diabetics without retinopathy and with background retinopathy, while there was no change observed in diabetics with severe retinopathy. These results show that diabetic adolescents and young adults with and without signs of retinopathy observed by fluorescein angiography have a reduced contrast sensitivity, which is more severe in patients with preproliferative/proliferative retinopathy. A significant amelioration of metabolic control is associated with an improvement of contrast sensitivity in all patients with the exception of those patients who had signs of preproliferative/proliferative retinopathy observed by fluorescein angiography. In summary, this longitudinal study provides the first evidence that reduced contrast sensitivity is reversible in diabetics with or without background retinopathy only.

Adolescent↗
PubMed1998

An audit of personal logs--1997.

Since 1991 all registered members of the Royal College of Speech and Language Therapists (RCSLT) have made a personal commitment to continuing education and continuing professional development (CPD). To support this commitment individual members have been required each year to complete a personal log of appropriate activities. The 1996-97 Department for Education and Employment (DfEE)/RCSLT 'Lifetime Learning Project' aimed to enhance and develop CPD services for members. One strand of the project was to make more use of the data available through and audit of members' personal logs. The range of CPD activities recorded were examined in relation to the type of practive, location, grade and work setting of respondents.

Education, Continuing↗
PubMed2001

Direction repulsion in unfiltered and ring-filtered Julesz textures.

Perceived directions of motion were measured for each of two superposed two-dimensional dynamic random patterns consisting of unfiltered or ring-filtered dense random-check (Julesz) textures. One pattern always moved in a cardinal direction (up, down, left, or right), and the other texture always moved in an oblique direction separated from the cardinal component by 20 degrees-80 degrees. Several cardinal/oblique speed ratios were tested. In Experiment 1, the textures were unfiltered. In Experiment 2, the textures were ring filtered and had the same center frequency (1, 2, or 4 cpd). In Experiment 3, a 1-cpd ring-filtered texture was paired with a 2-, 4-, or 8-cpd texture. Subjects consistently misperceived the directions of component motion in these experiments; the angular separation of movement of the two textures was perceptually exaggerated, a phenomenon referred to as direction repulsion (Marshak & Sekuler, 1979). The results show that (1) direction repulsion occurs across at least a fourfold range of spatial frequencies and a sixfold range of speed ratios, (2) direction repulsion varies systematically with speed ratio, and (3) across most conditions, direction repulsion is anisotropic--direction repulsion is more evident in the oblique directions than in the cardinal directions. These findings suggest that the spatiotemporal range of inhibitory interactions involved in motion transparency is much greater than previously appreciated.

Acceleration↗
PubMed1989

Spatial and temporal frequency in figure-ground organization.

Figure-ground organization of an ambiguous pattern can be manipulated by the spatial and temporal frequency content of the two regions of the pattern. Controlling for space-averaged luminance and perceived contrast, we tested patterns in which the two regions of the ambiguous pattern contained sine-wave gratings of 8, 4, 1, or 0.5 cycles per degree (cpd) undergoing on:off flicker at the rates of 0, 3.75, 7.5, or 15 Hz. For a full set of combinations of temporal frequency differences, with each spatial frequency the higher temporal frequency was seen as background for more of the viewing time. For two spatial frequency combinations, 1 and 4 cpd, and 1 and 8 cpd, tested under each of the four temporal frequencies, the lower spatial frequency region was seen as the background for more of the viewing time. When the effects of spatial and temporal frequency were set in opposition, neither was predominant in determining perceptual organization. It is suggested that figure-ground organization may parallel the sustained-transient response characteristics of the visual system.

Attention↗
PubMed1989

Spatial frequencies and the cerebral hemispheres: contrast sensitivity, visible persistence, and letter classification.

The hypothesis that the two cerebral hemispheres are specialized for processing different visual spatial frequencies was investigated in three experiments. No differences between the left and right visual fields were found for: (1) contrast-sensitivity functions measured binocularly with vertical gratings ranging from 0.5 to 12 cycles per degree (cpd); (2) visible persistence durations for 1- and 10-cpd gratings measured with a stimulus alternation method; and (3) accuracy (d') and reaction times to correctly identify digitally filtered letters as targets (L or H) or nontargets (T or F). One significant difference, however, was found: In Experiment 3, a higher decision criterion (beta) was used when filtered letters were identified in the right visual field than when they were identified in the left. The letters were filtered with annular, 1-octave band-pass filters with center spatial frequencies of 1, 2, 4, 8, and 16 cpd. Combining four center frequencies with three letter sizes (0.5 degrees, 1 degree, and 2 degrees high) made some stimuli equivalent in distal spatial frequency (cycles per object) and some equivalent in proximal spatial frequency (cycles per degree). The effective stimulus in the third experiment seemed to be proximal spatial frequency (cycles per degree) not distal (cycles per object). We conclude that each cerebral hemisphere processes visual spatial frequency information with equal accuracy but that different decision rules are used.

Adult↗
PubMed1991

Visual field effects in the discrimination of sine-wave gratings.

The time needed to decide whether the second of two successively presented sinusoidal gratings was of a higher or lower spatial frequency than the first was measured for spatial frequencies of 1, 2, 4, 8, and 12 cycles per degree (cpd) presented in either the left visual field (LVF) or right visual field (RVF). A LVF advantage was found for discriminating within the low-spatial-frequency range (i.e., 1 and 2 cpd), whereas a RVF advantage was found for discriminating within the high-spatial-frequency range (i.e., 4-12 cpd). These findings support the conclusion that hemispheric asymmetries in the processing of gratings arise when comparisons are made between the output of spatial-frequency channels.

Adult↗
PubMed2005

Predictive factors of low HCO3- levels in peritoneal dialysis patients.

BACKGROUND: Metabolic acidosis is a major metabolic abnormality in end-stage renal disease (ESRD) and alkali is provided with dialysis treatment to patients on chronic peritoneal dialysis (CPD) to keep their acid-base balance within normal serum HCO3- levels. METHODS AND RESULTS: We examined the levels of venous serum HCO3- in 163 patients on CPD and the predictive factors for HCO3- levels low enough to indicate metabolic acidosis. The mean value for HCO3- was 26+/-2.4 mmol/l and for anion gap was 13.1+/-3.1 mEq/l. A serum bicarbonate concentration of less than 24 mmol/l, compatible with metabolic acidosis, was observed in 13.5% of the patients. In a multivariate analysis HCO3- levels were directly correlated with older age and use of CaCO3- as phosphate binders, and inversely associated with serum potassium, the use of sevelamer and low lactate dialysis solutions. Higher serum urea levels, the use of low lactate solutions and sevelamer instead of CaCO3 were significantly predictive factors for HCO3- levels < 24 mmol/l. CONCLUSIONS: Venous HCO3- and anion gap values were within the normal ranges in stable CPD patients. In 13.5% of them, however, chronic metabolic acidosis was observed based on venous HCO3- levels < 24 mmol/l. Dietary protein intake, the use of sevelamer and low (35 mmol/l) concentration of lactate in dialysis solutions are important predictive factors for chronic metabolic acidosis in these patients.

Acidosis↗
PubMed2000

Nicotine patch therapy in 101 adolescent smokers: efficacy, withdrawal symptom relief, and carbon monoxide and plasma cotinine levels.

OBJECTIVES: To determine the efficacy of nicotine patch therapy in adolescents who want to stop smoking and to assess biochemical markers of smoking and nicotine intake. DESIGN: Nonrandomized, open-label trial using a 15 mg/16 h patch. SETTING: Two midwestern cities. SUBJECTS: One hundred one adolescents aged 13 through 17 years smoking at least 10 cigarettes per day (cpd). INTERVENTION: Six weeks of nicotine patch therapy and follow-up visits at 12 weeks and 6 months. MAIN OUTCOME MEASURES: Self-reported smoking abstinence verified by expired-air carbon monoxide (CO) level of no more than 8 ppm, nicotine withdrawal symptoms, and plasma cotinine level. RESULTS: Forty-one participants were female (mean [+/- SD] age, 16.5 [+/- 1.1] years). Median baseline smoking rate was 20.0 cpd (range, 10-40 cpd). Biochemically confirmed point prevalence smoking abstinence was 10.9% (11/101) at 6 weeks and 5.0% (5/101) at 6 months. The mean (+/- SD) plasma cotinine level at baseline was 1510.9 +/- 732.7 nmol/L; for nonsmoking subjects at weeks 3 and 6, 607.8 +/- 386.2 and 710.0 +/- 772.5 nmol/L, respectively. Plasma cotinine levels were correlated with CO levels at baseline (r = 0.27; P = .006), week 3 (r = 0.34; P = .004), and week 6 (r = 0.26; P = .03) and with mean cigarettes smoked per day during weeks 3 (r = 0.24; P = .04) and 6 (r = 0.30; P = .02). Mean smoking rates decreased significantly during the study, an effect that lessened at 12 weeks and 6 months. CONCLUSIONS: Nicotine patch therapy plus minimal behavioral intervention does not appear to be effective for treatment of adolescent smokers. Plasma cotinine and CO levels appear to be valid measures of smoking rates during the cessation process, but not at baseline. Smoking rates were reduced throughout the study. Additional pharmacological and behavioral treatments should be considered in adolescent smokers.

Administration, Cutaneous↗
PubMed1998

Continuous cycler therapy, manual peritoneal dialysis therapy, and peritonitis.

An increasing number of patients are prescribed a continuous-cycling regimen because standard manual peritoneal-dialysis exchanges alone are not sufficient in achieving adequate dialysis as defined by the Dialysis Outcome Quality Initiative. Consequently, the number of patients on continuous-cycler therapy is increasing. There is controversy as to whether there are differences in the development of peritonitis between patients maintained on manual therapy and those on continuous cycling therapy. As a result, we retrospectively reviewed the charts of all cycler peritoneal dialysis (CPD) patients maintained on either manual peritoneal dialysis (Baxter UltraBag; Group I) or continuous cycler peritoneal dialysis (Baxter HomeChoice Cycler; Group II) between 1 June 1994 and 31 December 1996. A total of 239 patients were in Group I and 106 in Group II. Both groups were similar in age, race, gender, and presence of diabetes mellitus, coronary artery disease, peripheral vascular disease, and gastrointestinal disease. There was no difference in the overall rate of peritonitis between the two groups of patients [1 episode in 10.4 patient-months (Group I) vs. 1 in 10.0 patient-months (Group II); -0.01843 to 0.02619]. The rates of Staphylococcus aureus peritonitis [1 episode in 48.5 patient-months (Group I) vs. 1 in 141.8 patient months (Group II); -0.06152 to -1.1689]; polymicrobial peritonitis [1 episode in 278.8 patient-months (Group I) vs. 1 in 1134 patient months (Group II): -0.0079 to -0.0478], and fungal peritonitis (1 episode in 202.7 patient-months (Group I) vs. no episodes (Group II); 0.00202 to 0.00785] were significantly lower among patients maintained on the Baxter HomeChoice Cycler. The rate of gram-negative peritonitis was higher among patients maintained on the Baxter HomeChoice Cycler, but this difference was not statistically significant [1 episode in 82.6 patient-months (Group I) vs. 1 episode in 45.4 patient months (Group II); 0.4723 to -0.0248]. We conclude that individual rates of peritonitis were different for patients maintained on either manual or continuous CPD therapy, while the overall rate of peritonitis was found to be similar for both groups of patients. The finding that there may be a difference with the gram-negative peritonitis rate is important since gram-negative peritonitis has been shown to have a more severe outcome in terms of morbidity, mortality, and patient dropout from CPD therapy. A larger, randomized, multicenter study comparing the rates of gram-positive, gram-negative, fungal, and polymicrobial peritonitis is warranted.

Female↗
PubMed1998

Hyperparathyroidism: a seven-year follow-up.

Hyperparathyroidism (HPT) is a common finding in patients with end-stage renal disease (ESRD). Most chronic peritoneal dialysis (CPD) patients with HTP can be successfully managed with phosphate binders, calcium supplements, and calcitriol therapy. Noncompliance with diet, prescribed binder, or calcitriol therapy may also lead to HPT. We reviewed New Haven CAPD unit patients who failed medical therapy and required parathyroidectomy (PTX) for control of severe HPT [sustained immunoreactive parathyroid hormone (iPTH) level > 600 pg/mL]. From 1990 to 1997, 18 out of 620 patients (3.0%) required PTX. Time on dialysis prior to PTX was 44.8 +/- 17.5 (mean +/- SD) months with a range of 13 to 71 months. The mean age was 43.6 +/- 11.8 years with a range of 30 to 66 years. There were 10 females and 8 males. Of the 18 patients, 14 had total parathyroidectomy with arm implants, and 4 had subtotal PTX. Seven of 18 patients had iPTH levels of < 100 pg/mL at 1 year post-PTX (5 patients with arm implants, 2 with subtotal PTX). Three patients required partial arm implant PTX to correct recurrent HPT. Pulse oral calcitriol (POC) was prescribed in 10 patients post PTX to maintain iPTH at target levels. Parathyroidectomy was necessary to correct HPT in 18 of 620 CPD patients from 1990 to 1997. The majority of these patients had excellent results after their PTX. Intact PTH levels of < 100 pg/mL for 1 year or more were noted in 5 of 14 patients with arm implants, and 2 of 4 patients with subtotal PTX. The significance of a persistent iPTH of < 100 pg/mL has yet to be determined in CPD patients.

Adult↗
PubMed2000

Inhibition of transforming activity of the ret/ptc1 oncoprotein by a 2-indolinone derivative.

ret-derived oncogenes are frequently and specifically expressed in thyroid tumors. In contrast to the ret receptor, ret oncoproteins are characterized by ligand-independent tyrosine-kinase activity and tyrosine phosphorylation. In this study, novel synthetic arylidene 2-indolinone compounds were evaluated as inhibitors of the ret/ptc1 tyrosine kinase. Four compounds inhibited ret/ptc1 activity in immunokinase assay (IC50 27-42 microM) including one (1,3-dihydro-5,6-dimethoxy-3-[(4-hydroxyphenyl) methylene)-2H-indol-2-one) (Cpd 1) that selectively inhibited the anchorage-independent growth of NIH3T3 transformants expressing the ret/ptc1 gene (NIH3T3ptc1 cells). Following exposure to Cpd 1, the transformed phenotype of NIH3T3ptc1 cells was reverted, within 24 hr, to a normal fibroblast-like morphology in adherent-cell culture. In these cells, the constitutive tyrosine phosphorylation of ret/ptc1, of the transducing adaptor protein shc and of a series of co-immunoprecipitated peptides became much reduced, as demonstrated by immunoprecipitation/Western-blot analyses. Data presented provide additional evidence that ret/ptc1 is directly implicated in malignant transformation, and demonstrate the ability of Cpd 1 to interfere in the signal transduction pathway constitutively activated by the ret/ptc1 oncoprotein. These results confirm the interest of the arylidene 2-indolinone class of tyrosine-kinase inhibitors as tools for the study of ret signaling and the control of cell proliferation in ret- and ret/ptcs-associated diseases.

Animals↗
PubMed1999

Tidal peritoneal dialysis to achieve comfort in chronic peritoneal dialysis patients.

Patients with end-stage renal disease on chronic peritoneal dialysis (CPD) can usually tolerate continuous ambulatory peritoneal dialysis (CAPD) or continuous cycling peritoneal dialysis (CCPD) without abdominal discomfort or pain. In some patients, pain or discomfort occurs with complete drain of the peritoneal dialysis solution or upon initiation of dialysis filling when the peritoneal cavity is empty. We report on the use of tidal peritoneal dialysis (TPD) as a modality to alleviate this pain. Of 136 patients in our CPD unit, 18 (13%) were complaining of pain with complete drain or upon instillation of PD fluid. All were placed on TPD after other causes for abdominal pain were excluded. Six patients were placed on 25% TPD, and 12 patients on 50% TPD. The mean Kt/V of the patients on TPD was 2.46 +/- 0.68. With TPD, all patients had complete relief of abdominal discomfort. Patients who develop abdominal pain with complete drain or fill when the abdominal cavity is empty would benefit from TPD and be able to continue with CPD.

Female↗
PubMed1999

Once-daily intraperitoneal cefazolin and oral ciprofloxacin as empiric therapy for the treatment of peritonitis.

The Ad Hoc Advisory Committee on Peritonitis Management has recommended intraperitoneal (i.p.) cefazolin and an aminoglycoside as empiric therapy for the treatment of peritonitis. Because most of our patients are on continuous cycler therapy, we developed a strategy of once-daily i.p. cefazolin and oral ciprofloxacin as empiric therapy. All patients in our unit that developed peritonitis were given a once-daily 2 g load of i.p. cefazolin, plus 500 mg ciprofloxacin orally, twice daily. Ciprofloxacin was given two hours after any phosphate binder or iron supplement. The i.p. cefazolin was allowed to dwell for at least six hours. The dialysate was then drained and chronic peritoneal dialysis (CPD) resumed. Organisms sensitive to cefazolin were treated for 14 days with once-daily cefazolin alone; resistant organisms were treated with alternative antibiotics. A total of 40 patients were treated with this empiric regimen. Of these, 35 (88%) successfully continued CPD therapy, 1 (2%) transferred to hemodialysis, and 4 (10%) expired two weeks after the onset of peritonitis. A total of 22 patients (55%) were treated successfully with once-daily i.p. cefazolin. Although once-daily i.p. cefazolin and oral ciprofloxacin permitted continuation of CPD therapy in most patients in this study, the therapy was not optimal. While vancomycin may have provided better coverage, recent reports of vancomycin-resistant enterococci and Staphylococcus aureus present a major concern.

Administration, Oral↗
PubMed2000

Age-related changes of defocus-specific contrast sensitivity in healthy subjects.

To investigate the effect of defocus on contrast sensitivity as a function of age in healthy subjects, the through focus contrast sensitivity was measured in 100 healthy subjects aged 20-69. Defocus-specific changes in contrast sensitivity reflect age-related changes in the optics of the eye. Tests were performed in cycloplegic eyes varying artificial pupil size (2, 4 and 6 mm), defocus (-1 to +2 D), and spatial frequency (1-16 cpd). Integrated contrast sensitivity was taken as a measure for the total amount of visual information transferred by the optical media. At optimal focus, integrated contrast sensitivity and log contrast sensitivity at 8 cpd showed a significant age-related decline. The log contrast sensitivity at 1 cpd appeared to be independent of age. The depth of focus for a 4-mm pupil increased significantly with age, even though contrast sensitivity at +2 D defocus decreases with age too, but not as much as the contrast sensitivity at optimal focus. Our study indicates that the effect of defocus on contrast sensitivity decreases with age; this was attributed to age-related changes in the optical media.

Adult↗
PubMed2000

Green tea polyphenol treatment to human skin prevents formation of ultraviolet light B-induced pyrimidine dimers in DNA.

Cancer chemopreventive effects of polyphenols from green tea (GTP) in mouse models of photocarcinogenesis are established. The present study is extended from mouse model to human system in vivo to determine the effect of topical application of GTP to human individuals against UV light-induced DNA damage in the form of cyclobutane pyrimidine dimers (CPDs) in the skin. UVB-induced CPDs were detected by immunohistochemical technique using monoclonal antibodies to thymine dimers. With the gradual increase in UVB dose, both erythema response and CPD formation in the skin was increased. GTP treatment inhibited both UVB-induced erythema response as well as CPD formation. Topical treatment with GTP (approximately 1 mg/cm2 of skin area) 20 min before human buttock skin (sun-protected site) exposure to UVB inhibited CPD formation in epidermis by 81, 70, 60, and 60% at 0.5, 1.0, 2.0, and 4.0 minimal erythema dose of UV exposure, respectively. Treatment of human skin with varying doses of GTP (1-4 mg/2.5 cm2 of skin area) before a single dose of UVB exposure (4.0 minimal erythema dose) decreased dose dependently the formation of UVB-induced CPDs in both epidermis and dermis. The inhibition of UVB-induced CPDs by GTP treatment may be, at least in part, responsible for the inhibition of photocarcinogenesis. Our data suggest that GTP may be used as a novel chemopreventive candidate and possible strategy to reduce UV-induced skin cancer risk in the human population.

Adult↗