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1.
Spinal Cord ; 55(9): 823-827, 2017 Sep.
Article in English | MEDLINE | ID: mdl-28462932

ABSTRACT

STUDY DESIGN: This was a cross-sectional questionnaire survey. OBJECTIVES: The objective of this study was to identify the care-seeking behavior of persons with spinal cord injury (SCI) with respect to the various health care providers and ascertain circumstances that lead to situations where required care was not received. SETTING: This study was conducted in the entire country of Switzerland. METHODS: Statistical analysis of frequency of annual visits to health care providers by 17 specialties, and description of situations where health care was required but not received, in persons with chronic SCI living in the community. RESULTS: Main medical contact person was the general practitioner (GP; visited by 88% during last 12 months). The physiotherapist (visited by 72%) was the health care provider with the most visits (average of 30 visits in 12 months). GPs, physiotherapists, urologists and spinal medicine specialists were often contacted in combination, by many participants, often for check-up visits. A situation where care was required but not received was reported by 53 (11%) of participants, with a substantially higher rate in migrants (29%). Main problems why care was not received were bladder and bowel problems and main reasons of care not received were regional or temporal unavailability. CONCLUSIONS: Individuals with SCI are frequent users of medical services. There is no group of medical specialists that covers all needs of persons with SCI, what emphasizes health care provision from a comprehensive perspective including a wide array of services. Instances with care required but not received appeared to be rare and more likely in participants with migration background.


Subject(s)
Ambulatory Care/statistics & numerical data , Patient Acceptance of Health Care , Spinal Cord Injuries/therapy , Chronic Disease , Complementary Therapies/statistics & numerical data , Cross-Sectional Studies , Female , Humans , Independent Living , Male , Middle Aged , Self Report , Spinal Cord Injuries/epidemiology , Switzerland
2.
Spinal Cord ; 55(9): 828-833, 2017 Sep.
Article in English | MEDLINE | ID: mdl-28462934

ABSTRACT

STUDY DESIGN: Cross-sectional survey. OBJECTIVES: To investigate annual rates and geographic variation of health care utilization in persons with spinal cord injury (SCI), and to identify factors associated with health care utilization. SETTING: Community setting, entire country of Switzerland. METHODS: Annual rates of planned and emergency visits to the general practitioner (GP), planned and emergency outpatient clinic visits and in-patient hospitalizations were compared between individuals with chronic SCI, over 16 years of age residing in Switzerland between late 2011 and early 2013 and a population sample (2012) of the Swiss general population. Risk factors for increased health service utilization were identified by means of regression models adjusted for spatial variation. RESULTS: Of 492 participants (86.2% response rate), 94.1% visited a health care provider in the preceding year, with most persons visiting GPs (88.4%) followed by outpatient clinics (53.1%) and in-patient hospitals (35.9%). The increase in utilization as compared with the general population was 1.3-, 4.0- and 2.9-fold for GP, outpatient clinic and in-patient hospital visit, respectively. GP utilization was highest in persons with low income (incidence rate ratio (IRR) 1.85) and old age (IRR 2.62). In the first 2 years post injury, health service visits were 1.7 (GP visits) to 5.8 times (emergency outpatient clinic visits) more likely compared with those later post injury. CONCLUSIONS: People with SCI more frequently use health services as compared with the general population, across all types of medical service institutions. GP services were used most often in areas where availability of specialized outpatient clinic services was low.


Subject(s)
Patient Acceptance of Health Care , Spinal Cord Injuries/epidemiology , Spinal Cord Injuries/therapy , Adolescent , Adult , Age Factors , Aged , Ambulatory Care/statistics & numerical data , Chronic Disease , Cross-Sectional Studies , Emergency Medical Services/statistics & numerical data , Female , Geography, Medical , Hospitalization , Humans , Male , Middle Aged , Regression Analysis , Risk Factors , Switzerland , Young Adult
3.
J Neurol ; 262(6): 1533-40, 2015 Jun.
Article in English | MEDLINE | ID: mdl-25904208

ABSTRACT

The causes of weight loss in Huntington's disease (HD) are not entirely clear. The aim was to identify risk factors that are associated with a loss of metabolically active tissues, i.e. fat-free mass. A consecutive cohort of non-diabetic HD participants (manifest HD, n = 43; CAG: mean 43.6.0 ± 3.6; preHD, n = 10; CAG: mean 41.4 ± 1.4) and 36 healthy controls was recruited. Twenty-five HD participants were early-stage HD (UHDRS Total Functional Capacity [TFC] stages I and II), 12 mid-stage HD (TFC stage III), and 6 participants were in late-stage HD (TFC stages IV and V). Food intake, basic metabolic rate and glucose homeostasis were assessed. In addition, fat-free mass was determined using bioelectric impedance analysis, and leptin, insulin and ghrelin as key metabolic regulators. Sex ratio and age were similar in HD participants (71 % women; age 50.6 ± 10.9) and controls (66 % women; age 46.4 ± 14.5). Body mass index (BMI) was lower in HD participants than controls (median 24.1 vs. 25.9, p = 0.04). However, fat-free mass and basic metabolic rate were not statistically different between groups and showed no association with disease burden. In controls and HD participants, leptin was the most important predictor of fat-free mass. While BMI was lower in HD participants, fat-free mass was similar to controls with leptin as its most important predictor. Leptin levels and fat-free mass measurements using bioelectric impedance analysis may be good screening tools to identify HD patients at risk for weight loss.


Subject(s)
Body Mass Index , Fats/metabolism , Huntington Disease/diagnosis , Huntington Disease/metabolism , Adult , Body Composition , Cell Count , Dietary Supplements , Electric Impedance , Female , Humans , Huntingtin Protein , Huntington Disease/genetics , Lymphocytes/pathology , Male , Middle Aged , Nerve Tissue Proteins/genetics , Nutrition Assessment , Predictive Value of Tests , Trinucleotide Repeats/genetics
4.
Minerva Anestesiol ; 81(12): 1338-45, 2015 Dec.
Article in English | MEDLINE | ID: mdl-25479469

ABSTRACT

BACKGROUND: Restrictions on visiting hours in the intensive care unit (ICU) are usually adopted worldwide. Current knowledge shows that these limitations are not necessary. In order to identify potential variables that are associated with restricted visiting times we carried out an observational study on visiting policy. METHODS: We conducted a questionnaire-based nationwide survey among all certified adult Swiss ICUs. An electronic questionnaire was sent by e-mail between May and June 2012 to all chief nurses. Length of permitted visiting time was taken as main endpoint to assess the association with different potential predictor variables using simple and multiple linear regression analysis. RESULTS: Response rate was 73 of 75 ICUs (97%). Only two ICUs (3%) have an unrestricted visiting policy. Median daily visiting time was 8 hours (range: 1.5 to 24 hours; interquartile range: 6-10 hours). Simple and multiple linear regression analysis demonstrated a significant effect in visiting hours between Italian- and French-speaking parts of Switzerland with 4.0 hours longer visiting hours in the former (P=0.039) without identifying other predictors. CONCLUSION: Swiss ICUs have less restrictive visiting policies compared to other Western countries; nevertheless very few Swiss ICUs have unrestricted visitations. Neither medical type of ICU, nor ICU infrastructure was determining the visiting policy in Swiss intensive care setting. Cultural factors, as captured by the linguistic areas are the only identified predictors of visiting hours. Since the current policy is not justified by clinical outcomes but based only on cultural settings, it needs to be definitively reconsidered and unrestricted visiting policies must become the rule rather than the exception.


Subject(s)
Intensive Care Units/organization & administration , Visitors to Patients , Appointments and Schedules , Health Care Surveys , Humans , Policy , Surveys and Questionnaires , Switzerland
5.
Psychol Med ; 44(15): 3151-64, 2014 Nov.
Article in English | MEDLINE | ID: mdl-25066766

ABSTRACT

BACKGROUND: To summarize the available evidence on the effectiveness of psychological interventions for patients with post-traumatic stress disorder (PTSD). METHOD: We searched bibliographic databases and reference lists of relevant systematic reviews and meta-analyses for randomized controlled trials that compared specific psychological interventions for adults with PTSD symptoms either head-to-head or against control interventions using non-specific intervention components, or against wait-list control. Two investigators independently extracted the data and assessed trial characteristics. RESULTS: The analyses included 4190 patients in 66 trials. An initial network meta-analysis showed large effect sizes (ESs) for all specific psychological interventions (ESs between -1.10 and -1.37) and moderate effects of psychological interventions that were used to control for non-specific intervention effects (ESs -0.58 and -0.62). ES differences between various types of specific psychological interventions were absent to small (ES differences between 0.00 and 0.27). Considerable between-trial heterogeneity occurred (τ²= 0.30). Stratified analyses revealed that trials that adhered to DSM-III/IV criteria for PTSD were associated with larger ESs. However, considerable heterogeneity remained. Heterogeneity was reduced in trials with adequate concealment of allocation and in large-sized trials. We found evidence for small-study bias. CONCLUSIONS: Our findings show that patients with a formal diagnosis of PTSD and those with subclinical PTSD symptoms benefit from different psychological interventions. We did not identify any intervention that was consistently superior to other specific psychological interventions. However, the robustness of evidence varies considerably between different psychological interventions for PTSD, with most robust evidence for cognitive behavioral and exposure therapies.


Subject(s)
Psychotherapy/standards , Stress Disorders, Post-Traumatic/therapy , Treatment Outcome , Humans
6.
Clin Exp Allergy ; 41(11): 1579-86, 2011 Nov.
Article in English | MEDLINE | ID: mdl-21729179

ABSTRACT

BACKGROUND: Experimental studies suggest that glutathione S-transferase (GST) genotypes modify nasal allergen responses induced by secondhand smoke (SHS) exposure. OBJECTIVE: We aimed to investigate whether GSTs affected systemic IgE and allergic rhinitis (AR) in SHS-exposed individuals from a population-based cohort. METHODS: Analyses comprised 2309 never-smokers from the Swiss study on air pollution and health in adults cohort, reporting SHS status at baseline and 11 years later. Outcomes were defined by total serum IgE≥100 kU/L, specific serum IgE determined by Phadiatop® ≥0.35 kU/L and self-reported AR. GSTP1 Ile105Val, GSTM1 and GSTT1 gene deletion genotypes were identified at the follow-up survey. RESULTS: After adjustment for relevant covariates, the homozygous GSTP1 105-Val genotype was negatively associated with high total IgE and high-specific IgE by Phadiatop®, notably in subjects persistently exposed to SHS (OR: 0.20, 95% CI 0.05-0.75; P=0.02, for high total IgE and OR: 0.29, 95% CI 0.10-0.89; P=0.03, for high specific IgE by Phadiatop®). Carrying at least one copy of the GSTM1 gene (non-null) showed a similar association for high specific IgE by Phadiatop® (OR: 0.41, 95% CI 0.22-0.76; P=0.004). No significant associations were found between GSTs and rhinitis. CONCLUSION AND CLINICAL RELEVANCE: In this large cohort, homozygosity for GSTP1 105-Val or carrying the GSTM1 non-null genotype decreased the risk of high total IgE or high specific IgE using Phadiatop® by nearly half in subjects exposed to SHS, as compared with subjects carrying opposite alleles. These findings underline the value of genetic susceptibility when evaluating the effects of environmental exposure on allergic illness. The potential long-term effects of persistent SHS exposure in genetically vulnerable individuals may be of public health relevance.


Subject(s)
Genotype , Glutathione Transferase/genetics , Hypersensitivity, Immediate/genetics , Rhinitis/genetics , Tobacco Smoke Pollution/adverse effects , Adult , Cohort Studies , Female , Humans , Hypersensitivity, Immediate/etiology , Immunoglobulin E/blood , Immunoglobulin E/immunology , Male , Middle Aged , Polymorphism, Genetic , Rhinitis/etiology
7.
Eur Respir J ; 35(5): 1088-97, 2010 May.
Article in English | MEDLINE | ID: mdl-19897550

ABSTRACT

The current study aimed to investigate incidence, prevalence and regional distribution of sarcoidosis in Switzerland with respect to environmental exposures. All sarcoidosis patients hospitalised between 2002 and 2005 were identified from the Swiss hospital statistics from the Swiss Federal Office for Statistics (Neuchâtel, Switzerland). Regional exposure characteristics included the regional distribution of different industrial sectors, agriculture and air quality. Co-inertia analysis, as well as a generalised linear model, was applied. The prevalence of "ever-in-life" diagnosed sarcoidosis, currently active sarcoidosis and sarcoidosis requiring hospitalisation was 121 (95% CI 93-149), 44 (95% CI 34-54) and 16 (95% CI 10-22) per 100,000 inhabitants, respectively. The mean annual incidence of sarcoidosis was 7 (95% CI 5-11) per 100,000 inhabitants. The regional workforce in the metal industry, water supply, air transport factories and the area of potato production, artificial meadows (grassland) and bread grains were positively associated with the frequency of sarcoidosis. The prevalence of sarcoidosis was higher than assumed based on former international estimates. Higher frequency was found in regions with metal industry and intense agriculture, especially production of potatoes, bread grains and artificial meadows.


Subject(s)
Environmental Exposure/adverse effects , Sarcoidosis/epidemiology , Female , Hospitalization/statistics & numerical data , Humans , Incidence , Linear Models , Male , Middle Aged , Monte Carlo Method , Prevalence , Risk Factors , Switzerland/epidemiology
8.
Swiss Med Wkly ; 139(5-6): 70-5, 2009 Feb 07.
Article in English | MEDLINE | ID: mdl-19204839

ABSTRACT

BACKGROUND: Ambrosia artemisiifolia (short name = Ambrosia common ragweed) pollen is a potent allergen and has recently been found in Switzerland, spreading from the southwest of the country. The aim of this study is to describe Ambrosia sensitisation rates in the population-based SAPALDIA cohort (Swiss Study on Air Pollution And Lung Diseases In Adults) and to test whether an increase in these rates could be observed. METHODS: Among the 6345 participants from 8 areas who provided blood samples in 1991 and 2002, 5823 had valid results for specific IgE against common inhalant allergens tested with Phadiatop. In 2002 Ambrosia sensitisation was measured and positive tests were analysed for Artemisia vulgaris (mugwort). Blood samples taken in 1991 in Ticino and Geneva were also tested for Ambrosia. RESULTS: Sensitisation rate (Phadiatop) did not increase significantly between the two surveys and sensitisation was found in 30% of the participants. A proportion of 7.9% showed specific IgE to Ambrosia pollen. The sensitisation rate in Lugano and Geneva had not changed substantially since 1991. Among those sensitised to Ambrosia 82% also showed specific IgE against Artemisia, suggesting a high rate of cross-reactivity. Only 1.3% were sensitized to Ambrosia alone. The incidence of asthma or hay fever in participants with specific IgE to Ambrosia pollen was not higher than in the general study population. CONCLUSION: Currently Ambrosia pollen does not appear to be an important cause of inhalant allergies in Switzerland. Sensitisation rates are low and have not increased since 1991. Due to cross-reactivity Ambrosia sensitisation may be a consequence of primary sensitisation to Artemisia. Elimination of Ambrosia plants is nevertheless mandatory to avoid a future increase.


Subject(s)
Ambrosia/immunology , Rhinitis, Allergic, Seasonal/epidemiology , Adult , Artemisia/immunology , Asthma/epidemiology , Cross Reactions/immunology , Humans , Immunization , Immunoglobulin E/immunology , Middle Aged , Public Health , Switzerland/epidemiology
9.
Am J Epidemiol ; 163(3): 289-97, 2006 Feb 01.
Article in English | MEDLINE | ID: mdl-16357113

ABSTRACT

Geographic mapping of the distribution of malaria is complicated by the limitations of the available data. The most widely available data are from prevalence surveys, but these surveys are generally carried out at arbitrary locations and include nonstandardized and overlapping age groups. To achieve comparability between different surveys, the authors propose the use of transmission models, particularly the Garki model, to convert heterogeneous age prevalence data to a common scale of estimated entomological inoculation rates, vectorial capacity, or force of infection. They apply this approach to the analysis of survey data from Mali, collected in 1965-1998, extracted from the Mapping Malaria Risk in Africa database. They use Bayesian geostatistical models to produce smooth maps of estimates of the entomological inoculation rates obtained from the Garki model, allowing for the effect of environmental covariates. Again using the Garki model, they convert kriged entomological inoculation rates values to age-specific malaria prevalence. The approach makes more efficient use of the available data than do previous malaria mapping methods, and it produces highly plausible maps of malaria distribution.


Subject(s)
Bayes Theorem , Cluster Analysis , Malaria/epidemiology , Malaria/transmission , Population Surveillance/methods , Adolescent , Adult , Aged , Child , Child, Preschool , Databases as Topic , Disease Transmission, Infectious , Endemic Diseases , Female , Geography , Humans , Male , Mali/epidemiology , Maps as Topic , Middle Aged , Prevalence
10.
Trop Med Int Health ; 10(1): 11-8, 2005 Jan.
Article in English | MEDLINE | ID: mdl-15655009

ABSTRACT

Randomized controlled trials have shown that insecticide-treated nets (ITNs) have an impact on both malaria morbidity and mortality. Uniformly high coverage of ITNs characterized these trials and this resulted in some protection of nearby non-users of ITNs. We have now assessed the coverage, distribution pattern and resultant spatial effects in one village in Tanzania where ITNs were distributed in a social marketing programme. The prevalence of parasitaemia, mild anaemia (Hb <11 g/dl) and moderate/severe anaemia (Hb <8 g/dl) in children under five was assessed cross-sectionally. Data on ownership of ITNs were collected and inhabitants' houses were mapped. One year after the start of the social marketing programme, 52% of the children were using a net which had been treated at least once. The ITNs were rather homogeneously distributed throughout the village at an average density of about 118 ITNs per thousand population. There was no evidence of a pattern in the distribution of parasitaemia and anaemia cases, but children living in areas of moderately high ITN coverage were about half as likely to have moderate/severe anaemia (OR 0.5, 95% CI: 0.2, 0.9) and had lower prevalence of splenomegaly, irrespective of their net use. No protective effects of coverage were found for prevalence of mild anaemia nor for parasitaemia. The use of untreated nets had neither coverage nor short distance effects. More efforts should be made to ensure high coverage in ITNs programmes to achieve maximum benefit.


Subject(s)
Bedding and Linens/supply & distribution , Insecticides/administration & dosage , Malaria/prevention & control , Mosquito Control/methods , Social Marketing , Anemia/epidemiology , Anemia/parasitology , Animals , Child, Preschool , Epidemiologic Methods , Female , Humans , Infant , Infant, Newborn , Insect Vectors , Malaria/epidemiology , Malaria/transmission , Male , Parasitemia/epidemiology , Parasitemia/prevention & control , Program Evaluation , Tanzania/epidemiology
11.
Am J Epidemiol ; 159(1): 64-72, 2004 Jan 01.
Article in English | MEDLINE | ID: mdl-14693661

ABSTRACT

A spatial analysis was carried out to identify factors related to geographic differences in infant mortality risk in Mali by linking data from two spatially structured databases: the Demographic and Health Surveys of 1995-1996 and the Mapping Malaria Risk in Africa database for Mali. Socioeconomic factors measured directly at the individual level and site-specific malaria prevalence predicted for the Demographic and Health Surveys' locations by a spatial model fitted to the Mapping Malaria Risk in Africa database were examined as possible risk factors. The analysis was carried out by fitting a Bayesian hierarchical geostatistical logistic model to infant mortality risk, by Markov chain Monte Carlo simulation. It confirmed that mother's education, birth order and interval, infant's sex, residence, and mother's age at infant's birth had a strong impact on infant mortality risk in Mali. The residual spatial pattern of infant mortality showed a clear relation to well-known foci of malaria transmission, especially the inland delta of the Niger River. No effect of estimated parasite prevalence could be demonstrated. Possible explanations include confounding by unmeasured covariates and sparsity of the source malaria data. Spatial statistical models of malaria prevalence are useful for indicating approximate levels of endemicity over wide areas and, hence, for guiding intervention strategies. However, at points very remote from those sampled, it is important to consider prediction error.


Subject(s)
Infant Mortality , Malaria/epidemiology , Models, Statistical , Adult , Child , Child Welfare , Child, Preschool , Demography , Endemic Diseases , Female , Health Surveys , Humans , Infant , Malaria/etiology , Male , Mali/epidemiology , Mothers/statistics & numerical data , Population Density , Prevalence , Risk Factors , Socioeconomic Factors
12.
Mol Microbiol ; 33(3): 590-8, 1999 Aug.
Article in English | MEDLINE | ID: mdl-10417649

ABSTRACT

Complex I is the site for electrons entering the respiratory chain and therefore of prime importance for the conservation of cell energy. It is generally accepted that the complex I-catalysed oxidation of NADH by ubiquinone is coupled specifically to proton translocation across the membrane. In variance to this view, we show here that complex I of Klebsiella pneumoniae operates as a primary Na+ pump. Membranes from Klebsiella pneumoniae catalysed Na+-stimulated electron transfer from NADH or deaminoNADH to ubiquinone-1 (0.1-0.2 micromol min-1 mg-1). Upon NADH or deaminoNADH oxidation, Na+ ions were transported into the lumen of inverted membrane vesicles. Rate and extent of Na+ transport were significantly enhanced by the uncoupler carbonylcyanide-m-chlorophenylhydrazone (CCCP) to values of approximately 0.2 micromol min-1 mg-1 protein. This characterizes the responsible enzyme as a primary Na+ pump. The uptake of sodium ions was severely inhibited by the complex I-specific inhibitor rotenone with deaminoNADH or NADH as substrate. N-terminal amino acid sequence analyses of the partially purified Na+-stimulated NADH:ubiquinone oxidoreductase from K. pneumoniae revealed that two polypeptides were highly similar to the NuoF and NuoG subunits from the H+-translocating NADH:ubiquinone oxidoreductases from enterobacteria.


Subject(s)
Klebsiella pneumoniae/enzymology , NADH, NADPH Oxidoreductases/chemistry , Sodium/metabolism , Bacterial Outer Membrane Proteins/metabolism , Biological Transport , Carbonyl Cyanide m-Chlorophenyl Hydrazone/pharmacology , Detergents , Dimethylamines , Electron Transport , Electron Transport Complex I , Kinetics , NAD/metabolism , Peptide Fragments/chemistry , Potassium Chloride/pharmacology , Protons , Sequence Analysis , Sodium Chloride/pharmacology , Sodium-Potassium-Exchanging ATPase/metabolism
13.
Biochemistry ; 37(51): 17843-50, 1998 Dec 22.
Article in English | MEDLINE | ID: mdl-9922151

ABSTRACT

Here we show that scavenger receptor class B type I is present in the small-intestine brush border membrane where it facilitates the uptake of dietary cholesterol from either bile salt micelles or phospholipid vesicles. This receptor can also function as a port for several additional classes of lipids, including cholesteryl esters, triacylglycerols, and phospholipids. It is the first receptor demonstrated to be involved in the absorption of dietary lipids in the intestine. In liver and steroidogenic tissues, the physiological ligand of this receptor is high-density lipoprotein. We show that binding of high-density lipoprotein and apolipoprotein A-I to the brush border membrane-resident receptor inhibits uptake of cholesterol (sterol) into the brush border membrane from lipid donor particles. This finding lends further support to the conclusion that scavenger receptor BI catalyzes intestinal cholesterol uptake. Our findings suggest new therapeutic approaches for limiting the absorption of dietary cholesterol and reducing hypercholesterolemia and the risk of atherosclerosis.


Subject(s)
CD36 Antigens/physiology , Cholesterol, Dietary/pharmacokinetics , Intestinal Absorption , Intestinal Mucosa/metabolism , Membrane Proteins , Receptors, Immunologic , Receptors, Lipoprotein/physiology , Amino Acid Sequence , Animals , Apolipoprotein A-I/metabolism , Blotting, Northern , CD36 Antigens/genetics , Cholesterol, Dietary/antagonists & inhibitors , Detergents , Humans , Immunoblotting , Intestinal Mucosa/ultrastructure , Microscopy, Immunoelectron , Microvilli/metabolism , Microvilli/ultrastructure , Molecular Sequence Data , Protein Binding , Rabbits , Rats , Receptors, Lipoprotein/antagonists & inhibitors , Receptors, Scavenger , Scavenger Receptors, Class B , Solubility , Temperature
14.
Ophthalmic Surg Lasers ; 28(7): 582-9, 1997 Jul.
Article in English | MEDLINE | ID: mdl-9243662

ABSTRACT

BACKGROUND AND OBJECTIVES: Plasma and cavitation bubble formation during optical breakdown in aqueous media may produce hydroxyl (*OH) radicals. The authors' objectives were to detect *OH produced by a neodymium:yttrium-aluminum-garnet (Nd:YAG) laser photodisruptor and to determine *OH concentration in relation to laser energy. MATERIALS AND METHODS: *OH was assayed by measuring absorbance of triiodide (I3-) in a potassium iodide (KI) solution exposed to optical breakdown by an Nd:YAG laser. The concentration-dependent reduction of radical production in relation to cystamine concentration was evaluated. RESULTS: I3- concentration increased linearly with total irradiation energy and decreased exponentially with increasing cystamine concentration. *OH concentration was calculated using extinction coefficients of I3- and chemical equations relating I3- formation to *OH. CONCLUSIONS: The authors calculated that approximately 4 x 10(-12) moles of *OH are produced in a typical posterior capsulotomy of 100 mJ of total energy. This *OH concentration could produce strand breaks in approximately 0.4% of vitreous hyaluronic acid molecules, but is unlikely to produce clinical effects.


Subject(s)
Aqueous Humor/metabolism , Aqueous Humor/radiation effects , Lasers , Cystamine/metabolism , Cystamine/radiation effects , Free Radicals/metabolism , Free Radicals/radiation effects , Humans , Spectrophotometry
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