Algorithms for automated oximetry along the retinal vascular tree from dual-wavelength fundus images

We present an automated method to perform accurate, rapid, and objective measurement of the blood oxygen saturation over each segment of the retinal vascular hierarchy from dual-wavelength fundus images. Its speed and automation (2 s per entire image versus 20 s per segment for manual methods) enables detailed level-by-level measurements over wider areas. An automated tracing algorithm is used to estimate vessel centerlines, thickness, directions, and locations of landmarks such as bifurcations and crossover points. The hierarchical structure of the vascular network is recovered from the trace fragments and landmarks by a novel algorithm. Optical densities (OD) are measured from vascular segments using the minimum reflected intensities inside and outside the vessel. The OD ratio (ODR=OD600/OD570) bears an inverse relationship to systemic HbO2 saturation (SO2). The sensitivity for detecting saturation change when breathing air versus pure oxygen was calculated from the measurements made on six subjects and was found to be 0.0226 ODR units, which is in good agreement with previous manual measurements by the dual-wavelength technique, indicating the validity of the automation. A fully automated system for retinal vessel oximetry would prove useful to achieve early assessments of risk for progression of disease conditions associated with oxygen utilization.     

Syndrome resembling PSP after surgical repair of ascending aorta dissection or aneurysm

Seven patients, after seemingly uncomplicated surgery for ascending aorta aneurysm or dissection, with or without aortic valve replacement, developed an unusual and fairly stereotyped biphasic neurologic disorder without imaging evidence of related cerebral ischemia or infarct. The initial phase was mild, nonprogressive, or receding. The latent and progressive phase closely resembled a progressive supranuclear palsy phenotype. The disorder may prove to be self-limiting but leaves the patients with considerable neurologic deficits.     

Polypoid endobronchial Hodgkin lymphoma with an initial response to photodynamic therapy

Endobronchial presentation of Hodgkin lymphoma is rare and can be confused clinically and radiographically with pulmonary small cell carcinoma. We present a case of an obstructive endobronchial presentation of nodular sclerosing classic Hodgkin lymphoma, initially misdiagnosed as small cell carcinoma, with endobronchial vasculitis and associated hemoptysis. Photodynamic therapy relieved the obstruction before induction of tumor-specific therapy. This case demonstrates the successful use of photodynamic therapy in obstructive endobronchial Hodgkin lymphoma.     

Oxidative DNA damage in vitamin C-supplemented guinea pigs after intratracheal instillation of diesel exhaust particles

The health effects of diesel exhaust particles (DEP) are thought to involve oxidative damage. We have investigated the effect of intratracheal DEP instillation to guinea pigs in three groups of 12 animals each given 0, 0.7, or 2.1 mg. Five days later guinea pigs exposed to DEP had increased levels of oxidized amino acids (gamma-glutamyl semialdehyde), DNA strand breaks, and 7-hydro-8-oxo-2'-deoxyguanosine (8-oxodG) in the lung. Bulky DNA ad- ducts were not significantly elevated in the lung. The antioxidant enzyme activity of glutathione reductase was increased in the lung of DEP-exposed guinea pigs, whereas glutathione peroxidase and superoxide dismutase enzyme activities were unaltered. There was no difference in DNA strand breaks in lymphocytes or urinary excretion of 8-oxodG at the two doses tested. Protein oxidations in plasma and in erythrocytes were not altered by DEP exposure. The concentrations of ascorbate in liver, lung, and plasma were unaltered by the DEP exposure. The results indicate that in guinea pigs DEP causes oxidative DNA damage rather than bulky DNA adducts in the lung. Guinea pigs, which are similar to humans with respect to vitamin C metabolism, may serve as a new model for the study of oxidative damage induced by particulate matter.     

A study of the photo-degradation kinetics of nifedipine by multivariate curve resolution analysis

A multivariate curve resolution method based on the combination of Kubista approach and iterative target transformation method of Gemperline has been proposed. This method is a soft model and need no information about the spectrum of the product and mechanism of the reaction. The method was used to study the degradation kinetics of nifedipin, 1,4-dihydro-2,6-dimethyl-4-(2-nitrophenyl)-3,5-pyridine dicarboxilic acid dimethyl ester, upon exposure to the light of a 40 W tungsten lamp. The spectra of the nifedipine, collected at different lighting times, were subjected to the factor analysis and two chemical components were detected in the reaction system. Pure spectra of the components involved and their concentration profiles were obtained. The results revealed that the photodecomposition kinetics of nifedipine is zero-order at the beginning of the reaction. However, when the reaction preceded more than 50%, the kinetics of reaction changed to a first-order manner. The rate constants for the zero-order and first order regions were estimated as regions (4.96+/-0.13) x 10(-9) M(-1) s(-1) and (6.22+/-0.10) x 10(-5) s(-1), respectively.     

Penetrating keratoplasty in young children with congenital hereditary endothelial dystrophy

PURPOSE: To report the visual results and success rate of penetrating keratoplasty (PKP) in a series of young children with congenital hereditary endothelial dystrophy (CHED). METHODS: This is a retrospective study on twenty-four eyes of 15 patients (seven male and eight female) operated on for CHED. Children less than 12 years of age at the time of surgery who were followed for at least 6 months were recalled. Characteristics of the patients, indications for PKP, final visual outcome, and graft clarity were evaluated. The following tests were employed: McNemmar test for evaluating visual results, Kaplan-Meyer analysis for determination of graft survival, and Mann-Whitney U test for evaluating the relationship between visual outcome and age at PKP. RESULTS: Patients' age at diagnosis and at initial PKP was 6.5 +/- 3.6 and 8.1 +/- 2.5 years, respectively. Follow-up period was 35.5 +/- 36.2 months. Visual acuity could be evaluated by Snellen chart in 19 eyes. Preoperative visual acuity was less than 20/80 in all of these. Postoperatively, visual acuity was less than 20/80 in nine eyes (47.4%) (P < 0.002). Visual acuity improved in 18 (94.7%) of 19 eyes. There was no relationship between age at initial PKP and final visual outcome (P = 0.35). At the last examination (24 grafts), 19 were clear (79.1%), two were hazy (8.3%), and three were opaque (12.5%). Allograft rejection was seen in 10 eyes (43.4%), seven of which were endothelial. Excluding one case of trauma, all graft failures resulted from endothelial rejection. The probability of primary graft survival was 88% at 3 years and 74% at 5 years. CONCLUSION: Regarding the difficulties in pediatric keratoplasty and the absence of a relationship between postoperative visual outcome and age at keratoplasty, a conservative approach and careful risk-benefit ratio evaluation are recommended in patients with CHED.     

Evaluation of the effect on outcomes of the route of administration of corticosteroids in acute Vogt-Koyanagi-Harada disease

PURPOSE: To compare the effect on outcomes of the route of administration of corticosteroids in acute Vogt-Koyanagi-Harada disease. DESIGN: Retrospective comparative interventional case series. METHODS: SETTINGS: Nine international uveitis specialty clinics. STUDY POPULATION: Forty-eight patients presenting over a three-year period to a study center with acute Vogt-Koyanagi-Harada disease. INTERVENTION: Initial treatment with corticosteroid either orally (Oral only group) or intravenously followed by an oral taper (IV+Oral group). MAIN OUTCOME MEASURES: Change in visual acuity with treatment; development of ocular complications, including visually significant cataract, choroidal neovascularization, subretinal fibrosis, fundus pigment migration, nummular hypopigmented lesions, and diffuse fundus depigmentation; use of immunosuppressive therapy. RESULTS: The Oral only group comprised 15 patients (31%) and the IV+Oral group 33 patients (69%). Median follow-up was 15 months. There was no difference in duration of follow-up between groups (P = .234). There was no difference in the change in visual acuity between groups, adjusting for initial visual acuity (P = .402). There were no differences in the rates of development of visually significant cataract, fundus pigmentary changes, or in the rate of use of subsequent immunosuppressive therapy between treatment groups. No patients developed choroidal neovascularization or subretinal fibrosis over the study period. CONCLUSIONS: Route of administration of corticosteroid had no detectable effect on change in visual acuity nor on the development of visually significant complications over the study period. Prospective trials are necessary to address speed of resolution and definitively answer outcome questions.     

Decomposing socioeconomic inequality in infant mortality in Iran

BACKGROUND: Although measuring socioeconomic inequality in population health indicators like infant mortality is important, more interesting for policy purposes is to try to explain infant mortality inequality. The objective of this paper is to quantify for the first time the determinants' contributions of socioeconomic inequality in infant mortality in Iran. METHODS: A nationally representative sample of 108 875 live births from October 1990 to September 1999 was selected. The data were taken from the Iranian Demographic and Health Survey (DHS) conducted in 2000. Households' socioeconomic status was measured using principal component analysis. The concentration index of infant mortality was used as our measure of socioeconomic inequality and decomposed into its determining factors. RESULTS: The largest contributions to inequality in infant mortality were owing to household economic status (36.2%) and mother's education (20.9%). Residency in rural/urban areas (13.9%), birth interval (13.0%), and hygienic status of toilet (11.9%) also proved important contributors to the measured inequality. CONCLUSIONS: The findings indicate that socioeconomic inequality in infant mortality in Iran is determined not only by health system functions but also by factors beyond the scope of health authorities and care delivery system. This implies that in addition to reducing inequalities in wealth and education, investments in water and sanitation infrastructure and programmes (especially in rural areas) are necessary to realize improvements of inequality in infant mortality across society. These findings can be instrumental for the recent 5 year Economic, Social and Cultural Development Plan of Iran, which identified the reduction of inequalities in social determinants of health.     

Fruits, vegetables and risk of renal cell carcinoma: a prospective study of Swedish women

Findings of epidemiologic studies on the relationship between fruit and vegetable consumption and renal cell carcinoma (RCC) risk have been inconclusive. To study the association between fruits and vegetables and risk of RCC in a population-based prospective cohort study of Swedish women, we collected dietary information from 61,000 women age 40-76 years by a food-frequency questionnaire. During 13.4 years of follow-up 122 women developed RCC. Cox proportional hazards models were used to estimate relative risks (RR) with 95% confidence interval (CI). Women consuming 5 or more servings of fruit and vegetables daily had a relative risk of 0.59 (95% CI = 0.26-1.34) in comparison to them consuming less than once daily. When fruits and vegetables were examined separately, those who consumed more than 75 servings per month of fruits or vegetables had multivariate relative risk of 0.59 (95% CI = 0.27-1.25) and 0.60 (95% CI = 0.31-1.17) respectively, compared to those consuming 11 or less servings per month. Within the group of fruits, the strongest inverse association was observed for banana (p = 0.07 by Wald test). The risk of RCC increased monotonically with increasing intake frequencies of fruit juice (p-value for trend = 0.10). Within the group of vegetables, the strongest inverse association was observed for root vegetables (p = 0.03 by Wald test). The risk of RCC decreased with increasing consumption frequencies of white cabbage (p for trend = 0.07). Frequent consumption of salad vegetables (once or more per day) decreased the risk by 40% (RR = 0.60; 95% CI = 0.30-1.22), in comparison to no consumption. Our results suggested that high consumption of fruits and vegetables might be associated with reduced risk of RCC.