bluuebunny/crossref_metadata_2025_split huggingface dataset:
Systematic measurement errors involved in over‐refraction using an autorefractor (Grand‐Seiko WV‐500): is measurement of accommodative lag through spectacle lenses valid?
Authors: Kimura Shuhei , Hasebe Satoshi , Ohtsuki Hiroshi 
Published: May 2007

AbstractPurpose:  Lags of accommodation in ametropic children are often evaluated through spectacle lenses (over‐refraction). This study investigated the validity of over‐refraction when using an autorefractor.Methods:  Using an autorefractor (Shin‐Nippon SRW‐500/Grand‐Seiko WV‐500), refractive readings were obtained in 25 cyclopleged eyes (mean ± S.D. refraction: −3.44 ± 3.56 D, range: from −10.56 to +0.25 D) while placing spherical lenses of different power (from −5.00 to +5.00 D) in front of the eye at a vertex distance of 12 mm. Based on the refractive readings with and without the lens, and the lens power, measurement errors were estimated. Similarly, the measurement errors were estimated also in model eyes of −10.00, −4.75, 0.00 and +10.00 D. The results were compared with ray‐tracing simulations based on the internal specifications of the autorefractor.Results:  Measurement errors were found unless the power of the spectacle lens was equal to the refractive error of the eye. When the spectacle lens power was greater (less myopic or more hyperopic) than the refraction of the eye, the measurement error was negative in sign and greater than −0.3 D. It follows that, when an accommodative response is measured in myopic subjects, the refractive reading usually becomes more myopic than the refraction of the eye including the accommodative response; hence, the accommodative response is overestimated, and the lag of accommodation is underestimated.Conclusions:  The autorefraction through spectacle lenses involved systematic measurement errors. The extent of the errors is usually small but needs to be taken into account in a comparative study of accommodative responses among different refractive groups.
Technical Note: The effect of refractive blur on colour vision evaluated using the Cambridge Colour Test, the Ishihara Pseudoisochromatic Plates and the Farnsworth Munsell 100 Hue Test
Authors: Thyagarajan Sri , Moradi Philip , Membrey Luke , Alistair D. , Laidlaw H. 
Published: May 2007

AbstractThe results of a prospective study examining the effect of refractive blur on colour vision performance in normal subjects measured with three different colour vision tests are reported. The Farnsworth Munsell 100 Hue (FM100) and Cambridge Colour Test (CCT) results were significantly affected at +6 D of spherical refractive blur, whereas those from the Ishihara Pseudoisochromatic Plate (IPP) test were not. In a clinical setting, correction of refractive error up to 3 D for colour vision testing with these tests may not be required. Poor colour vision should not be attributed solely to refractive causes of poor visual acuity (Snellen equivalent: >6/36). Fastest test times were achieved using IPP, followed by CCT.
Does prior instillation of a topical anaesthetic alter the pupillary mydriasis produced by tropicamide (0.5%)?
Authors: Haddad David E. , Rosenfield Mark , Portello Joan K. , Krumholz David M. 
Published: May 2007

AbstractPurpose:  It is common clinical practice to instill a topical anaesthetic prior to the instillation of a mydriatic agent into the eye. The main rationale for using the anaesthetic is to increase corneal permeability, so that more of the mydriatic agent reaches the receptor sites within the anterior chamber. It addition, as mydriatics generally cause stinging, prior use of an anaesthetic should reduce the degree of discomfort. The aim of the present study was to determine whether the efficacy of mydriasis produced by an antimuscarinic agent is enhanced by prior instillation of a topical anaesthetic.Method:  The study was performed using a double‐masked protocol on 20 healthy young subjects. One drop of either proparacaine (proxymetacaine) (0.5%) or isotonic saline was instilled into the eye, followed by one drop of tropicamide (0.5%). Pupil diameter was measured using a customized photographic device at 0, 10, 20, 30 and 60 min following drug instillation. Additionally, subjects were asked to rate the degree of discomfort following the instillation of each drop on a scale from 0 (no discomfort) to 10 (agony).Results:  There was no significant difference in either the rate of onset of mydriasis, or the maximum pupil diameter achieved between the two conditions. The mean change in pupil diameter produced by tropicamide after the instillation of saline or proparacaine was 2.31 and 2.28 mm, respectively. The mean discomfort scores following instillation of saline and proparacaine were 1.15 and 1.65, respectively, while mean discomfort scores following the instillation of tropicamide after saline or proparacaine were 4.00 and 0.85, respectively.Conclusions:  Instillation of a topical anaesthetic does significantly reduce the degree of discomfort produced by the instillation of tropicamide. However, it does not produce any significant increase in either the magnitude or rate of onset of mydriasis.
Refractive, biometric and topographic changes among Portuguese university science students: a 3‐year longitudinal study
Authors: Jorge J. , Almeida J. B. , Parafita M. A. 
Published: May 2007

AbstractPurpose:  The aim of this study was to investigate the changes in refractive, biometric and topographic ocular parameters among university students in Portugal during a 3‐year period.Methods:  A 3‐year longitudinal study comprised 118 Portuguese university students from the School of Science (34 males and 84 females; mean age 20.6 ± 2.3 years). Ocular refraction, corneal curvature (CR) and eccentricity, and A‐scan biometry were conducted under cycloplegia. The sphero‐cylindrical refractive results were converted into vector representations (M, J0 and J45) for statistical analysis. Myopia was defined as M ≤ −0.50 D, emmetropia as M > −0.50 D and < +0.50 D and hyperopia as M ≥ +0.50 D.Results:  At the beginning of the study sphero‐cylindrical refraction (M) ranged from −6.75 to +3.00 D, with a mean value of 0.23 ± 1.46 D [mean ± standard deviation (S.D.)]. Eighty‐three students presented astigmatism with a mean value (±S.D.) of −0.52 ± 0.41 D, and a maximum of −2.25 D. After 3 years the mean refractive change for the M component was −0.29 ± 0.38 D (p < 0.001) and non‐significant changes of 0.02 ± 0.16 D (p = 0.281) for the J0 component and 0.01 ± 0.09 D (p = 0.784) for the J45 component. Prevalence of myopia increased by 5.1%, while the prevalence of hyperopia decreased by 9.4%. Myopia progression ≥0.5 D was observed in 22% of the population. Axial length, vitreous chamber depth and lens thickness increased significantly while anterior chamber depth and central CR did not change significantly.Conclusions:  This study shows a change in refraction towards myopia accompanied by a vitreous chamber elongation in a Portuguese population comprising science students during the first three years of their university course. Younger students were more likely to show clinically significant myopia progression.
Reaching and grasping with restricted peripheral vision
Authors: González‐Alvarez Carmen , Subramanian Ahalya , Pardhan Shahina 
Published: May 2007

AbstractAim:  To investigate how prehensile movements, such as reaching and grasping, are affected by different fields of view when both haptic and visual information are available.Methods:  Ten volunteers with normal vision (mean age 24.5 years) participated. Subjects picked up an object with a full monocular field of view (FOV) and with two different sizes of pinholes which simulated a central FOV of 23° and 11° respectively. The Vicon motion analysis system was used to record and reconstruct the 3D‐kinematic data. The kinematic parameters measured were total time of the movement, maximum velocity, time to maximum velocity, deceleration time, maximum grip aperture, time to maximum grip aperture and time taken after maximum grip aperture.Results:  Restricting the FOV affected both the transport and grasp components of the movement. The maximum velocity decreased (p = 0.008) and the maximum grip aperture increased (p = 0.003) with both restricted FOV when compared with the full field. The execution or on‐line control of both reach and grasp components were also longer (p = 0.005 and p = 0.002 respectively) for the 11° FOV only.Conclusions:  Reducing the FOV to 11° (an absence of peripheral vision) affects the planning and execution of the reach and the grasp component of the movement. Restricting the FOV to 23° of central vision (with some peripheral cues present) affects only the planning of the reach and grasp component of the movement. Peripheral visual cues are therefore more important for the on‐line control than for the planning of the movement. The findings of this study have important clinical implications in patients who suffer from ocular diseases in which peripheral vision gradually decreases.
Conversion of statistics calculated from the coordinates of the power matrix to those of principal meridional representation of power
Authors: Abelman H. , Abelman S. 
Published: May 2007

AbstractPrincipal meridional powers of thick astigmatic systems, like the eye, are not necessarily at right angles. The consequence is a class of phenomena included in the category commonly described as irregular astigmatism. The conventional principal meridional representation of power, however, is unsuited to quantitative analysis. The coordinates of the power matrix are scalars well suited to quantitative analysis. In a sizeable sample of such data it would be tedious to contemplate all the individual observations to obtain knowledge of the material. A standard summary in a manageable form is needed for concise reliable description to deal with all of the data. This paper is concerned with measures of dispersion of a data sample of coordinates of the power matrix, conversion to dispersion of principal meridional representation of power (or any other clinical or scientific power representation), and the nature of the dispersion.
Effect of Critical Access Hospital Conversion on Patient Safety
Authors: Li Pengxiang , Schneider John E. , Ward Marcia M. 
Published: May 2007

Background. The Medicare Rural Hospital Flexibility Program of the 1997 Balanced Budget Act allowed hospitals meeting certain criteria to convert to critical access hospitals (CAH) and changed their Medicare reimbursement mechanism from prospective payment system (PPS) to cost‐based.Objective. To examine the impact of CAH conversion on hospital patient safety.Data Source. Secondary data on hospital patient safety indicators (PSIs), hospital CAH status, patient case‐mix, and market variables, for 89 Iowa rural hospitals during 1997–2004.Study Design. We employed quasi‐experimental designs that use both control groups and pretests. The hospital‐year was the unit of analysis. We used generalized estimating equations logit and random‐effects Tobit models to assess the effects of CAH conversion on hospital patient safety. The models were adjusted for patient case‐mix and market variables. Sensitivity analyses, which varied by sample and statistical model, were used to examine the robustness of our findings.Data Extraction Methods. PSIs were computed from Iowa State Inpatient Databases (SIDs) using Agency for Healthcare Research and Quality indicators software. Hospital CAH status was extracted from Iowa Hospital Association. Patient case‐mix variables were extracted from Iowa SIDs. Market variables came from Area Resource File (ARF).Principal Findings. CAH conversion in Iowa rural hospitals was associated with better performance of risk‐adjusted rates of iatrogenic pneumothorax, selected infections due to medical care, accidental puncture or laceration, and composite score of four PSIs, but had no significant impact on the observed rates of death in low‐mortality diagnosis‐related groups (DRGs), foreign body left during procedure, risk‐adjusted rate of decubitus ulcer, or composite score of six PSIs.Conclusion. CAH conversion is associated with enhanced performance of certain PSIs.
Neuropsychological function in Greek patients with chronic hepatitis C
Authors: Karaivazoglou Katerina , Assimakopoulos Konstantinos , Thomopoulos Konstantinos , Theocharis George , Messinis Lambros , Sakellaropoulos George , Labropoulou‐Karatza Chryssoula 
Published: May 2007

AbstractBackground: Research has shown that hepatitis C virus (HCV) infection is associated with subclinical neuropsychological deficits in the absence of hepatic encephalopathy.Methods: The current study assessed 32 Greek HCV patients without hepatic encephalopathy using standardized neuropsychological measures and compared them with 20 healthy controls and 29 hepatitis B virus (HBV)‐infected patients. Patients and controls did not differ on age, educational level, depression or fatigue severity. Moreover, strict criteria were used to exclude any risk factor for cognitive impairment.Results: Chronic HCV patients performed significantly worse than healthy controls on verbal learning and memory (P=0.029). However, hepatitis C and hepatitis B patients were similarly impaired in cognitive function, suggesting that the observed abnormalities are not HCV specific. HCV patients' cognitive capacity was further associated with liver disease severity as indicated by fibrosis stage (r=−0.602, P=0.011). In contrast, cognitive decline did not correlate with patients' psychological distress, indicating that biological mechanisms might be implicated in its pathogenesis. Finally, after controlling for age and educational level, cirrhotic and non‐cirrhotic patients appeared to be equally impaired.Conclusions: In conclusion, this study confirmed previous findings and added further to the existing literature concerning the negative influence of HCV infection on cognition.
Evaluation of hepatic steatosis by ultrasound in patients with chronic hepatitis C virus infection
Authors: Hirche T. O. , Ignee A. , Hirche H. , Schneider A. , Dietrich C. F. 
Published: May 2007

AbstractObjective: To compare two alternative ultrasound parameters, hepatic vein flow (HVF) pattern and presence of focal hypoechoic areas (FHA) within the liver hilus, as non‐invasive predictors of liver steatosis in patients with chronic hepatitis C virus (HCV) infection.Design: In 122 consecutive patients with chronic HCV infection, the HVF pattern and presence of FHA within the liver hilus were assessed by Duplex–Doppler and B‐mode sonography. All patients underwent liver biopsy and the sonographic results were compared with a histological score of steatosis used as the gold standard for this purpose. Association of fatty infiltrations with clinical and sonographic features were evaluated by a stepwise logistic regression analysis.Results: Reduced HVF and FHA, but not standard clinical and laboratory parameters, strongly correlated with steatosis on histology (P<0.001). Both sonographic parameters made excellent predictions for the subgroup of patients with severe steatosis, particularly when both tests were combined [sensitivity (SE) 95%, specificity (SP) 96%, positive predictive value (pPV) 93%, negative predictive value (nPV) 97%, and accuracy 96%]. However, the sensitivity and accuracy of HVF pattern analysis were markedly reduced when all degrees of steatosis were defined as positive (SE 71%, SP 76%, pPV 81%, nPV 64%, and accuracy 73%). In contrast, the dichotomous parameter FHA remained a powerful indicator even under the latter conditions (SE 74%, SP 100%, pPV 100%, nPV 72%, and accuracy 84%). The combination of both sonographic tests resulted in improved sensitivity (82%), but significant loss of specificity (76%) and accuracy (80%) for prediction of liver steatosis.Conclusion: Sonographic evaluation of reduced HVF and FHA within the liver hilum is easy to perform, non‐invasive, and, when present, gives a high degree of confidence in the diagnosis of liver steatosis. However, the lack of sonographic evidence of steatosis cannot definitively exclude the presence of mild steatosis, as shown on biopsy.
Stronger Neo‐Minophagen C™, a glycyrrhizin‐containing preparation, protects liver against carbon tetrachloride‐induced oxidative stress in transgenic mice expressing the hepatitis C virus polyprotein
Authors: Hidaka Isao , Hino Keisuke , Korenaga Masaaki , Gondo Toshikazu , Nishina Sohji , Ando Miye , Okuda Michiari , Sakaida Isao 
Published: May 2007

AbstractBackground/Aim: Stronger Neo‐Minophagen C™ (SNMC), a glycyrrhizin‐containing preparation, has been used as a treatment for chronic hepatitis for more than 30 years in Japan, and shown to be effective in preventing the development of hepatocellular carcinoma in chronic hepatitis C patients, but its underlying mechanisms remain elusive. The aim of this study was to investigate if SNMC had an anti‐oxidative effect, as oxidative stress has been proposed to be one of the mechanisms of liver injury in hepatitis C virus (HCV)‐associated chronic liver diseases.Methods: The protective effect of SNMC against carbon tetrachloride (CCl4)‐induced liver injury was examined using transgenic mice expressing the HCV polyprotein.Results: A small dose of CCl4 (10 μl/kg of body weight) significantly increased the serum alanine aminotransferase (ALT) level and hepatic malondialdehyde content, decreased hepatic reduced glutathione (GSH) content and induced ultrastructural alterations of hepatic mitochondria in transgenic mice, but not in nontransgenic mice. A single SNMC treatment equivalent to a clinical dose significantly restored the serum ALT level and hepatic malondialdehyde and GSH contents, attenuated the ultrastructural alterations of hepatic mitochondria, and increased mRNA expression of γ‐glutamylcysteine synthetase (γ‐GCS).Conclusions: Transgenic mice expressing the HCV polyprotein are abnormally vulnerable to oxidative stress. SNMC protects hepatocytes against CCl4‐induced oxidative stress and mitochondrial injury in the presence of HCV proteins by restoring depleted cellular GSH.
Severe portal hypertension secondary to arterio‐portal fistula: salvage surgical treatment
Authors: Dumortier Jérôme , Pilleul Frank , Adham Mustapha , Vochelle Véronique , Hervieu Valérie , Bouffard Yves , Valette Pierre‐Jean , Scoazec Jean‐Yves , Boillot Olivier 
Published: May 2007

AbstractBackground: Arterio‐portal fistulas (APFs) are rare vascular disorders of various origins that can lead to severe portal hypertension. Even if surgery was initially the treatment of choice, more recently, interventional radiological procedures have been considered as the first line therapeutic option.Case Report: A man with no history of liver disease was admitted for abdominal pain and distension. Abdominal ultrasonography with Doppler, magnetic resonance imaging and computed tomography (CT) scan showed ascites, splenomegaly and a probable APF between the left branches of both the hepatic artery and portal vein, associated with hepatofugal portal flow. Upper gastrointestinal endoscopy revealed large oesophageal varices without bleeding. A celiac and mesenteric arteriography and a splenic arteriography were performed and confirmed the existence of multiple intrahepatic APFs. The initial treatment consisted of two sessions of percutaneous transcatheter endovascular embolization. Unfortunately, ascites worsened, and the patient did not respond to diuretic treatment. Therefore, a surgical treatment was considered to be the only suitable treatment because of the absence of improvement after embolization procedures. A left hepatectomy with hepatic artery ligation was performed. Clinical evolution was favourable; an improvement of ascites was obtained; control ultrasonography and CT scan disclosed no residual haemodynamic abnormality; and the portal vein was normal with a hepatopedal flow. Currently, 12 months after surgery, the clinical condition of the patient is good.Conclusion: Percutaneous treatment of portal hypertension by embolizing multiple large APF has been described to be an effective method. Nevertheless, failure of such conservative treatment is possible and must lead to a salvage surgery.
Risk factors for human immunodeficiency virus infection among blood donors in Sao Paulo, Brazil, and their relevance to current donor deferral criteria
Authors: De Almeida Neto Cesar , McFarland William , Murphy Edward L. , Chen Sanny , Nogueira Fatima Aparecida Hangai , Mendrone Alfredo , Salles Nanci Alves , Chamone Dalton Alencar Fischer , Sabino Ester Cerdeira 
Published: May 2007

BACKGROUND: The objective of this study was to investigate risk factors of human immunodeficiency virus (HIV)‐seropositive blood donors in Brazil and to determine if current donor deferral criteria are appropriate.STUDY DESIGN AND METHODS: Demographic and behavioral data among cases with confirmed HIV seropositivity (n = 272) were compared with those who had a false‐positive serology (n = 468) between January 1999 and December 2003 in a case‐control analysis with logistic regression.RESULTS: Risk factors that should have resulted in predonation deferral were reported by 48.9 percent of HIV‐positive and 9.4 percent of false‐positive donors. In multivariate analysis, male cases were significantly more likely to report male‐male sex (adjusted odds ratio [AOR], 26.2; 95% confidence interval [CI], 7.8‐87.4), a previous sexually transmitted disease diagnosis (AOR, 3.2; 95% CI, 1.5‐6.9), exchanging money for sex (AOR, 2.1; 95% CI, 1.0‐4.2), and at least two partners in the past 12 months (AOR, 2.3; 95% CI, 1.4‐3.6). HIV‐positive male donors were also more likely to be reactive for the presence of hepatitis C virus antibody (AOR, 4.0; 95% CI, 1.3‐12.0) and hepatitis B virus core antibody (AOR, 3.8; 95% CI, 1.9‐7.7). Female cases were more likely to report an intravenous drug user partner (AOR, 12.4; 95% CI, 1.3‐120.2), a sexual partner with multiple sex partners or who had a history of sex with a sex worker (AOR, 13.0; 95% CI, 2.7‐63.2), and at least two partners in the past 12 months (AOR, 2.2; 95% CI, 1.0‐5.3).CONCLUSION: A substantial number of HIV‐infected donors reported a risk factor that could have been identified in the predonation screening. Male‐male sexual behavior was still the strongest determinant of HIV status in the studied population.
Sterility testing of hematopoietic progenitor cell products: a single‐institution series of culture‐positive rates and successful infusion of culture‐positive products
Authors: Padley Douglas J. , Dietz Allan B. , Gastineau Dennis A. 
Published: May 2007

BACKGROUND: Administration of culture‐positive hematopoietic progenitor cells (HPCs) causing adverse events has been a hypothesized yet largely unmeasured risk of the clinical practice of HPC transplantation. To enhance patient safety, the FDA has issued regulations prohibiting the use of culture‐positive HPCs. Numerous studies have reported the infusion of culture‐positive HPCs; however, the low frequency of adverse events prevents accurate determination of this risk.STUDY DESIGN AND METHODS: Product culture results and clinical outcomes from January 1998 through March 2006 representing 7233 HPC collections for 2118 transplants at a single institution were reviewed.RESULTS: A total of 119 units of HPCs (1.6%) intended for 95 patients were culture‐positive. Of the 69 patients transplanted with culture‐positive HPCs, 5 received products with cultures pending, and 64 received products with the positive culture results known. One of 69 patients had a new positive blood culture 5 days after infusion with the same species as the product. There was not a clinically relevant difference in the rate of infusion‐related symptoms reported for patients who received culture‐positive products compared to all infusions. The survival of patients who received culture‐positive products (n = 69) was not different from all HPC recipients (n = 2046; p = 0.419).CONCLUSION: No infusion‐related risks of culture‐positive HPCs to patient safety were identified. Our data suggest that the decision to use culture‐positive HPCs must be made in the context of the global risks associated with transplants such as remobilization, replacement product availability, and the nature of the organism.