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PubMed1988

Comparison of coronary stenosis quantitation results from on-line digital and digitized cine film images.

To examine the effects of digital image acquisition mode and subtraction techniques on the results of coronary stenosis quantitation, 100 discrete lesions from 45 patients undergoing routine diagnostic angiography were analyzed in each of 3 image types: direct on-line digital, electrocardiogram-gated digital subtraction and digitized cine film images. For the geometric measurements (minimal lumen diameter and percent diameter stenosis) correlation coefficients for 2-way comparisons among the image types ranged from 0.90 to 0.96. Linear regression slopes ranged from 0.93 to 1.00, with intercepts from 0.03 to 0.07 mm for minimal diameter and -0.5 to 4.4% for percent diameter stenosis. For the videodensitometric percent area stenosis data, the correlation coefficients ranged from 0.80 to 0.89, with linear regression slopes from 0.84 to 0.89 and intercepts from 8.3 to 12.8%. Thus, the results of quantitative geometric measurements of coronary stenosis severity were not strongly affected by image acquisition mode (on-line versus cine film digitization) or by electrocardiogram-gated digital subtraction, while densitometric data correlated less well when on-line digital and digitized cine film acquisition methodology were compared.

Angiography↗

PubMed1998

Enhancement of radiation response by paclitaxel in mice according to different treatment schedules.

PURPOSE: The aim of our study was to determine if paclitaxel could be used as a radiosensitizer in vivo. MATERIALS AND METHODS: Paclitaxel was tested as a single agent and combined with an X-ray treatment. Paclitaxel was administered i.p. in doses from 30 to 120 mg/kg b.w. to (C3D2F1) mice bearing spontaneous mammary carcinoma. Tumor growth delay (TGD) or tumor control dose (TCD50, radiation dose needed to induce local tumor control in 50% of irradiated animals) and moist desquamation dose (MDD50, radiation dose needed to induce serious moist desquamation in 50% of the non-tumor-bearing feet) were the endpoints. DNA flow cytometric analysis was performed. RESULTS: DNA analysis demonstrated a G2/M block of tumor cells and a depletion of cells in S phase, with a maximum at 24 h from paclitaxel administration. Administering paclitaxel, in graded doses, 15 min before a 10-Gy X-ray treatment resulted in a linear regression line, almost parallel to that with paclitaxel alone, with a growth delay of about 6 days. In contrast, varying the X-ray dose with a constant paclitaxel injection (45 mg/kg b.w.) treatment showed some degree of synergism as the linear regression curves diverged. Interval time and sequence between paclitaxel administration and a 10 Gy X-ray treatment did not influence TGD. Protocols with paclitaxel at 30, 45, or 60 mg/kg were combined with radiation treatments at various doses (from 10 to 65 Gy). Values of TCD50 varied from 50.8 Gy for X-ray alone to 31.8 Gy for paclitaxel 60 mg/kg + X-ray. No differences were observed among MDD of different protocols. CONCLUSIONS: These results suggest that, under some conditions, paclitaxel combined with radiation can show superadditive effects and this result combined with the lack of severe normal tissue damage indicate that a favorable therapeutic gain can be obtained.

Animals↗

PubMed2000

Poor prediction of blood transfusion requirements in adult liver transplantations from preoperative variables.

STUDY OBJECTIVE: To assess the ability of preoperative information to predict intraoperative blood transfusion requirements in adult orthotopic liver transplantation. DESIGN: Retrospective review. SETTING: Liver transplantation program in a referral center. PATIENTS: 583 sequential adult patients undergoing orthotopic liver transplantation. MEASUREMENTS: Preoperative variables with a previously demonstrated relationship to intraoperative transfusion were identified from the literature. These variables were then collected retrospectively from 583 consecutive liver transplantations. Relationships between these and intraoperative blood transfusion requirements were examined by both univariate analyses and multiple linear regression analysis. RESULTS: Univariate analysis revealed significant associations between blood transfused and the following preoperative variables: age, gender, diagnosis, presence of grade 3 or 4 encephalopathy, pseudocholinesterase, creatinine, bilirubin, mean pulmonary artery pressure, activated partial thromboplastin time, and platelet count. Multiple linear regression analysis with correction for diagnosis identified age, creatinine, bilirubin, and pseudocholinesterase as independent predictors; for the final model r(2) = 0.22. CONCLUSION: Preoperative variables are poor predictors of intraoperative transfusion requirements even when significant associations exist, identifying a small proportion of the variability observed. A predictive approach based on this method would be too inaccurate to be of clinical use. The majority of the variability in transfusion requirements during liver transplantation most likely results from intraoperative and donor organ factors.

Analysis of Variance↗

PubMed2006

Regulatory effect of amino acids on the pasting behavior of potato starch is attributable to its binding to the starch chain.

The binding of an amino acid, glycine (Gly), alanine (Ala), epsilon-aminocaproic acid (-AC), monosodium glutamate (GluNa), or lysine (Lys), to starch was examined by a biomolecular interaction analyzer (IAsys). A starch sample (ATS) hydrolyzed to an extent of 1% hydrolysis rate with 15% sulfuric acid was used as a model starch for the binding examination. The reducing end of ATS was oxidized by the Somogyi reagent, and the conversion of the reducing end to the carboxyl group of ATS was confirmed by a carboxylic acid fluorescence labeling reagent. The oxidized ATS was immobilized to the amino group of a sensor cuvette by using water-soluble carbodiimide and N-hydroxysuccinimide through an amide bond. The IAsys examination showed that Gly, Ala, and epsilon-AC scarcely bound to the immobilized starch chains but that GluNa and Lys favorably bound with their increasing concentrations. The relative binding index (RBI) of each amino acid was defined by the ratio of the slope of the linear regression equation between the binding response and the concentration for each amino acid to that for Gly. Because the relationships between the RBI and the pasting characteristics (pasting temperature, peak viscosity, breakdown, and swelling index) could each be expressed by a linear regression equation with a high correlation coefficient, it is concluded that the regulation of the pasting behavior of starch with an amino acid is caused by binding of the amino acid to the starch chains.

Amino Acids↗

PubMed2000

Influence of age on the steady state disposition of drugs commonly used for the eradication of Helicobacter pylori.

BACKGROUND: The success of eradication therapy for Helicobacter pylori might be affected by the age of patients. AIM: To investigate whether disposition of drugs commonly used for H. pylori eradication is age-dependent. METHODS: Trough steady state serum levels of lansoprazole or ranitidine, amoxycillin, clarithromycin and metronidazole were monitored in 232 patients during the last dosing interval of a 5-day quadruple H. pylori eradication regimen. Detailed pharmacokinetic analysis was performed in 28 patients. RESULTS: Linear correlations between age and trough serum levels were observed with lansoprazole (r=0.25; P=0.002), ranitidine (r=0. 38; P=0.001) and clarithromycin (r=0.36; P < 0.0001). These associations were also inversely dependent of creatinine clearance for ranitidine (r=0.36; P=0.001) and clarithromycin (r=0.30; P < 0. 0001). Multiple linear regression revealed age as an important factor influencing trough serum levels of lansoprazole, clarithromycin and ranitidine. There were significant inverse relationships between creatinine clearance and area under curve of ranitidine (r=0.88; P < 0.0001) and amoxycillin (r=0.56; P=0.002). Multiple linear regression revealed serum creatinine as the most important factor influencing the area under curve of ranitidine, clarithromycin and amoxycillin. CONCLUSIONS: Age per se has little influence on pharmacokinetics of amoxycillin and ranitidine, which depend more on age-dependent decline in renal function. The influence of age, but not renal function was established for lansoprazole. Age and renal function have independent impacts on clarithromycin disposition.

2-Pyridinylmethylsulfinylbenzimidazoles↗

PubMed2003

Variation of pH, conductivity and potential values in chromium (VI) removal by wool.

Variation of pH, conductivity and potential values in chromium (VI) removal by wool was investigated in this study. In addition to chromium (VI) concentrations, pH, conductivity and potential values were also traced during the experimental studies. After applying linear regression to experimental data, it was seen that there was a relationship between pH, conductivity, potential values and chromium (VI) concentrations in the aqueous solution after treatment with wool. This relationship was evaluated in the light of the analyses of the linear regression. Kinetic data and adsorption isotherms for chromium (VI) adsorption by wool were also determined.

Adsorption↗

PubMed1995

A statewide surveillance system for antimicrobial-resistant bacteria: New Jersey.

OBJECTIVES: To determine the validity of an active, hospital laboratory isolate-based surveillance system in estimating rates of infection and to evaluate the use of surveillance data in describing institutional risk factors for increased rates of infection. Methicillin-resistant Staphylococcus aureus (MRSA) was chosen as the prototype organism for these evaluations. DESIGN: Correlation Study: linear regression analysis and Student's t test were used to evaluate the correlation between number of MRSA isolates and number of MRSA infections in acute-care hospitals. Cross-Sectional Study: Student's t test, analysis of variance, and multiple linear regression analysis were used to evaluate the association between mean annual rate of MRSA blood isolates and institutional risk factors for increased rates of infection. SETTING: Acute-care hospitals, New Jersey. RESULTS: The number of MRSA blood isolates was significantly correlated with MRSA blood infections (R, 0.78; P < .01) and provided a good proxy measure for number of infections. Multivariate analysis demonstrated hospital location in the inner city (P = .02) and number of occupied beds (P < .01) to be independently associated with increased mean annual rates of MRSA blood isolates in acute-care hospitals. CONCLUSIONS: This surveillance system is a valid tool for the estimation of institutional rates of infection and for the determination of institutional risk factors for increased rates of infection. It is ideal for further population-based investigations of antimicrobial-resistant bacteria.

Acute Disease↗

PubMed1987

Comparison of arterial blood gas with continuous intra-arterial and transcutaneous PO2 sensors in adult critically ill patients.

We compared the partial pressure of oxygen directly via a continuous intra-arterial probe (PiaO2) and indirectly using a transcutaneous device (PtcO2) with simultaneously obtained arterial blood PaO2. The PiaO2 values were measured using a bipolar oxygen sensor placed through an 18-ga arterial catheter. The PtcO2 values were measured using a transcutaneous O2-CO2 sensor placed on the abdomen. Seven critically ill, hemodynamically stable, ventilator-dependent adult patients were studied. Measurements were obtained at varying concentrations (0.25 to 1.0) of inspired oxygen after a 10-min stabilization. A total of 78 simultaneous values were obtained; by linear regression: PiaO2 = 0.91 PaO2 + 1.39 (r = .98, standard errors of the estimate [SEE] = 18.6); PtcO2 = 0.39 PaO2 + 36.2 (r = .89, SEE = 14.1). To assess these instruments as trend monitors, we compared the changes in simultaneous PaO2, PiaO2, and PtcO2 values; by linear regression: delta PiaO2 = 0.90 delta PaO2 + 3.88 (r = .96, SEE = 27.7); delta PtcO2 = 0.43 delta PaO2 + 5.6 (r = .94, SEE = 15.2). We conclude that, although these instruments correlate highly with the PaO2, the SEE was substantial and therefore may limit their clinical reliability in adults. Any acute or clinically significant change in PiaO2 or PtcO2 should be confirmed with a blood gas PaO2.

Adult↗

PubMed2005

Preoperative risk factors and surgical complexity are more predictive of costs than postoperative complications: a case study using the National Surgical Quality Improvement Program (NSQIP) database.

OBJECTIVE: This single-center study tested the hypothesis that preoperative risk factors and surgical complexity predict more variation in hospital costs than complications. BACKGROUND: Complications after surgical operations have been shown to significantly increase hospital cost. The impact on complication-related costs of preoperative risk factors is less well known. METHODS: The National Surgical Quality Improvement Program (NSQIP) preoperative risk factors, surgical complexity, and outcomes, along with hospital costs, were analyzed for a random sample of 5875 patients on 6 surgical services. Operation complexity was assessed by work RVUs (Centers for Medicare and Medicaid Services Resource Based Relative Value Scale). The difference in mean hospital costs associated with all variables was analyzed. Multiple linear regression was used to determine the cost variation associated with all variables separately and combined. RESULTS: Fifty-one of 60 preoperative risk factors, work RVUs, and 22 of 29 postoperative complications were associated with higher variable direct costs (P < 0.05). Linear regressions showed that risk factors predicted 33% (P < 0.001) of cost variation, work RVUs predicted 23% (P < 0.001), and complications predicted 20% (P < 0.001). Risk factors and work RVUs together predicted 49% of cost variation (P < 0.001) or 16% more than risk factors alone. Adding complications to this combined model modestly increased prediction of costs by 4% for a total of 53% (P < 0.001). CONCLUSION: Preoperative risk factors and surgical complexity are more effective predictors of hospital costs than complications. Preoperative intervention to reduce risk could lead to significant cost savings. Payers and regulatory agencies should risk-adjust hospital cost assessments using clinical information that integrates costs, preoperative risk, complexity of operation, and outcomes.

Databases as Topic↗

PubMed1982

Noninvasive cardiac output determination using inhaled oxygen-15-labeled carbon dioxide.

Inhaled oxygen-15-labeled carbon dioxide (CO2*) is hydrated in the alveolar capillary blood to produce oxygen-15-labeled water (H2O*). This allows noninvasive delivery of a traceable indicator into the pulmonary circulation. Removal of oxygen-15 marker from the lung is a function of pulmonary perfusion. Two techniques were evaluated for computing cardiac output (CO) following single bolus inhalation of CO2*: 1) continuous monitoring of arterial blood activity through an external detector and 2) noninvasive positron imaging of oxygen-15-label washout from the chest and simultaneous emergence of activity in arterial blood. In seven mongrel dogs studied using technique 1, 46 determinations of CO were made from 1.2 to 8.0 l/min and compared with simultaneous indocyanine green dye-dilution determination. Correlation coefficient was 0.90 with slope of linear regression of 1.05. In 12 mongrel dogs studied using technique 2, 23 determinations of CO were made from 0.9 to 9.2 l/min and compared with simultaneous indocyanine green dye determination. Correlation coefficient was 0.985 (P less than 0.001) with slope of linear regression of 0.898. This noninvasive technique (2) for determination of CO is independent of assumptions regarding regional ventilation or perfusion of the lung and appears valid in animal studies.

Animals↗

PubMed1996

Differences between patients' and physicians' evaluations of outcome after total hip arthroplasty.

The purpose of this study was to compare patients' and physicians' evaluations of the results of 147 total hip arthroplasties. The patients and physicians independently evaluated pain and over-all satisfaction with the outcome of the procedure using a 10.0-centimeter visual-analog scale. They also answered a questionnaire with which they assessed general health, functional ability, and pain. The mean (and standard deviation) analog rating for pain (with 0.0 centimeters indicating no pain and 10.0 centimeters, severe pain) was 1.7 +/- 2.6 centimeters as assessed by the patients and 1.1 +/- 1.8 centimeters as assessed by the physicians (p < 0.001, paired t test). The mean analog rating for over-all satisfaction (with 0.0 centimeters indicating poor and 10.0 centimeters, excellent) was 8.6 +/- 2.1 centimeters as assessed by the patients and 8.8 +/- 1.7 centimeters as assessed by the physicians (p = 0.07, paired t test). There was a marked disparity between the patients' and the physicians' scores when the patients assigned a low score to a particular area. For the thirty patients who rated the pain as more than 4.0 centimeters, the mean analog rating was 6.8 +/- 2.1 centimeters according to the patients, while it was 3.6 +/- 2.7 centimeters according to the physicians (p < 0.001, linear regression). The mean analog rating for over-all satisfaction according to the nineteen patients who rated this parameter as less than 7.0 centimeters was 3.8 +/- 2.0 centimeters, while the mean rating according to the physicians 6.5 +/- 2.8 centimeters (p < 0.001, linear regression). The patients' and physicians' evaluations were similar regarding the results of the total hip arthroplasty when the patients had little or no pain and were satisfied with the result. However, the disparity increased as the patients' ratings for pain increased and their ratings for over-all satisfaction decreased. This study highlights a discrepancy between patients' and physicians' evaluations of the results of total hip arthroplasty. This discrepancy increased when the patient was not satisfied with the outcome. The use of patients' self-administered questionnaires as well as traditional physician-generated assessments may provide a more complete evaluation of the results of total hip arthroplasty.

Activities of Daily Living↗

PubMedDate not supplied

[The application of the concise exposure index to repetitive movement tasks of the upper limbs in various production settings: preliminary experience and validation].

A summary of eight investigations is presented, which were carried out using standardised methods, for the purpose of quantifying exposure to tasks involving repetitive movements of the upper limbs, as well as quantifying the prevalence of Work Related Musculo Skeletal Disorders of the upper limbs in groups of exposed workers. A total of 462 exposed workers were examined, and the study also took into account the data pertaining to a matched control group comprising 749 workers not exposed to any specific occupational risk. Regarding the quantification of exposure to increased risk, use was made of a Concise Index (OCRA), proposed by the Authors in a previous publication. The data resulting from the eight investigations were used for the study of measurements and models of association among the exposure variables (mainly represented by the OCRA index), as well as the effect variables represented by the prevalence of the various WMSDs of the upper limbs taken both individually and jointly. Significant associations were reported between the OCRA index and an effect indicator represented by the prevalence of all the WSMDs of the upper limbs, calculated on the number of upper limbs at risk. When a logarithmic conversion of the relative exposure (OCRA) and injury indices was carried out, a simple linear regression model resulted which seems to provide a satisfactory predictive performance of the risk of WMSDs of the upper limbs, based on the exposure index. The study confirmed the efficacy of various other models designed to predict effects based on multiple linear regression functions, in which the independent variables are represented by both the OCRA exposure index and by parameters relative to the breakdown by sex and age of the groups of exposed workers.

Adult↗

PubMed2005

Aortic pulse wave velocity is associated with the presence and quantity of coronary artery calcium: a community-based study.

We investigated the relationship of aortic pulse wave velocity (aPWV), a measure of central arterial stiffness, with the presence and quantity of coronary artery calcium (CAC) in a community-based sample of adults without prior history of heart attack or stroke (n=401, mean age 59.8 years, 53% men). ECG-gated waveforms of the right carotid and right femoral artery were obtained by applanation tonometry, and aPWV was calculated using established methods. CAC was measured noninvasively by electron beam computed tomography, and CAC score was calculated. aPWV was significantly correlated with log(CAC +1; r=0.41; P<0.0001) and pulse pressure (r=0.47; P<0.0001). Multivariable logistic and linear regression models were used to identify independent predictors of the presence and quantity of CAC, respectively. In multivariable logistic regression analyses, aPWV was associated with the presence of CAC (P=0.011) after adjustment for age, male sex, total cholesterol, high-density lipoprotein cholesterol, diabetes, history of smoking, systolic blood pressure, body mass index, and use of hypertension and statin medications. In multivariable linear regression analyses, aPWV was significantly associated with log(CAC +1) after adjustment for the covariates enumerated above (P<0.0001). aPWV remained significantly associated with both the presence and quantity of CAC even after the additional adjustment for diastolic blood pressure. We conclude that aPWV is related to subclinical coronary atherosclerosis independent of conventional risk factors (including indices of blood pressure) and may be a biomarker of cardiovascular risk in asymptomatic individuals.

Adult↗

PubMed1994

Characteristics of vasopressin release during controlled reduction in arterial pressure.

Because of the interruption of the descending sympathetic nervous pathways, individuals with cervical spinal cord injury experience orthostatic hypotension when in an upright posture. The changes in hemodynamic parameters that occur during upright posture can be closely monitored and quantitated during progressive head-up tilting on a tilt table. We have utilized this method to assess the response of vasopressin and other vasoactive hormones to gradual, progressive reductions in arterial pressure and to identify possible threshold responses to baroreceptor stimulation in human subjects. Studies were performed in 12 quadriplegic subjects, 3 paraplegic subjects, and 3 normal control subjects. Data from the studies in paraplegic and normal subjects did not differ and were pooled as control data. In quadriplegic subjects, mean arterial pressure (MAP) decreased from 93 +/- 4 mm Hg to 60 +/- 3 mm Hg in a closely correlated (r = 0.948, p < 0.002) linear relationship with increasing degrees of tilt, whereas in control subjects, MAP increased from 81 +/- 4 to 88 +/- 3 mm Hg. Plasma vasopressin concentrations (Pavp) increased minimally in quadriplegic subjects until MAP was reduced to levels that were 25% to 30% lower than MAP with subjects in the supine posture. Beyond this level of hypotension, Pavp increased markedly. Log-linear regression analysis of these data showed a highly significant correlation (r = 0.85, p < 0.0002) between in Pavp and MAP, which defines Pavp as an exponential function of decreasing MAP. Changes in Pavp in control subjects were minimal during incremental head-up tilting. In contrast, plasma renin activity (PRA) increased in both quadriplegic and control subjects. Log-linear regression analysis of these data showed highly significant correlates between in PRA and degree of tilt in both quadriplegic (r = 0.958, p < 0.0002) and control (r = 0.873, p < 0.0002) subjects. Plasma atrial natriuretic peptide concentrations decreased linearly with increasing degrees of tilt. The rate of decline in Panp was greater in quadriplegic than in control subjects. These studies provide additional evidence that Pavp increases exponentially as a function of decreasing MAP and suggest that a critical threshold level of hypotension exists at which vasopressin release accelerates rapidly in response to baroreceptor stimulation. At this level of reduced MAP, Pavp reaches levels that are potentially capable of exerting a pressor effect.

Adult↗

PubMed1996

Fixation strength of interference screw fixation in bovine, young human, and elderly human cadaver knees: influence of insertion torque, tunnel-bone block gap, and interference.

A failure analysis of interference screw fixation was performed to test the hypothesis that bovine and/or elderly human cadavers are appropriate models for bone-patellar tendon-bone anterior cruciate ligament (ACL) reconstruction fixation studies. Failure mode is an important criterion for validating experimental models. The bovine, young human, and elderly human failure loads were 799 +/- 261 N, 655 +/- 186 N, and 382 +/- 118 N, respectively, and the failure modes were 75%, 69%, and 30% tissue failures, respectively. The similarities between the bovine and young human models in failure loads and failure modes indicate that bovine models are appropriate for ACL reconstruction fixation studies. The statistically significant differences between the young human and elderly human models in failure loads and failure modes indicate that elderly human cadavers are not an appropriate model for ACL reconstruction fixation studies. The differences in failure modes are consistent with previous studies using elderly human cadavers in which the predominant failure mode was bone block pullout. The tissue failures observed in the bovine and young human models contradict previous studies suggesting fixation strength is the weakest link in bone-patellar tendon-bone ACL reconstruction. Results of linear regression modeling showed statistically significant correlations between insertion torque and failure load (R2 = 0.44, P < 0.0001) and interference (defined as the screw outer thread diameter minus the tunnel-bone block gap) and insertion torque (R2 = 0.18, P = 0.003) when data from all models was combined. Results for the bovine model multiple regression showed a statistically significant regression of insertion torque (linear) and interference (quadritic) versus failure load (R2 = 0.56, P = 0.02). Regression slopes for screw diameter (P = 0.52) and gap size (P = 1.00) were not statistically significant. These results indicate that insertion torque and interference are independent predictors of failure load and should be included in future interference screw studies in addition to bone block dimensions, tunnel size, gap size, and screw diameter. Clinicians may consider using insertion torque and interference as indicators of postoperative graft fixation regarding rehabilitation decisions.

Adult↗

PubMed2004

An ecological study of caries experience, school performance and material deprivation in 5-year-old state primary school children.

AIM: To investigate whether measures of school performance and socioeconomic circumstances could be used as indicators of caries experience in 5-year-old Wandsworth state primary schoolchildren. DESIGN: An ecological study using aggregated caries data collected in the British Association for the Study of Community Dentistry (BASCD) Oral Health Survey of 5-year-old children (2001), Jarman scores generated from national census data and matched by school postcodes (1991), school performance results in English, mathematics and Linguistic Awareness of Reading Readiness test (LARR; literacy) and free school meals recipient data from the Local Education Authority, Research and Evaluation Unit (2001). SETTING: State primary schools in the London borough of Wandsworth, UK. SUBJECTS: All 55 Wandsworth state primary schools including 1968 5-year-old pupils. OUTCOME MEASURE: The school mean dmft score. RESULTS: Simple linear regression analysis demonstrated that school mean dmft was statistically significantly associated with all five explanatory variables: English (P = 0.001), mathematics (P = 0.002), LARR (P < 0.001), the percentage of children receiving free school meals (P < 0.001) and the school address Jarman score (P = 0.02). Stepwise multiple linear regression identified the LARR score and the percentage of children receiving free school meals as the strongest indicators of school mean dmft score explaining 41% of the variation in school mean dmft score. CONCLUSION: Early school performance results in English, mathematics and LARR, the percentage of children receiving free school meals and school address Jarman scores were good indicators of school mean dmft scores in 5-year-old children in the Wandsworth state primary schools.

Child, Preschool↗

PubMed2006

Functional field score: the effect of using a Goldmann V-4e isopter instead of a Goldmann III-4e isopter.

PURPOSE: To investigate the underestimation of field loss in functional field score (FFS) between the Goldmann isopters III-4e and V-4e in visually impaired patients, in order to develop a predictive model for the FFS(III-4e) based on FFS(v-4e) that adjusts for possible confounders. Although the visual field is generally evaluated using Goldmann isopter III-4e, it has the disadvantage that not all low-vision patients are able to see the stimulus corresponding to this isopter. METHODS: Goldmann visual fields were obtained from 58 patients with a variety of eye diseases. Eligibility criteria were age of 18 years or older and valid results of a Goldmann III-4e and V-4e visual field test in at least one eye. Linear regression was used to develop the model, setting FFS(III-4e) as the dependent variable and FFS(V-4e) as the independent one. RESULTS: The FFS(V-4e) was higher than the FFS(III-4e), the mean difference being 14.56 points (95% CI, 12.48 -16.64). Multiple linear regression analysis showed that age, functional acuity score, primary eye disease, and central-peripheral loss were not confounders for the prediction of FFS(III-4e). FFS(III-4e) was estimated with the following equation: FFS(III-4e) = -19.25 + 1.063 x FFS(V-4e). CONCLUSIONS: The relationship between FFS(III-4e) and FFS(V-4e) is linear, and the FFS(V-4e) can be used to estimate the FFS(III-4e). In practice, just subtracting 19.25 points of the value of FFS(V-4e) will be sufficient to estimate the value of FFS(III-4e). This model should give confidence about using the bigger isopter for determining the visual impairment of a person by the FFS.

Adult↗

PubMed2006

Premature rupture of the fetal membranes: is the amnion the major determinant?

OBJECTIVE: The objective of the study was to evaluate the relative contributions of amnion and chorion to the strength of fetal membranes and to correlate these findings with gestational age. STUDY DESIGN: Fetal membranes from 78 pregnancies were tested for biaxial puncture force using a blunt, instrumented probe with a low-force load cell connected through a load cell conditioner to an oscilloscope. The average of 2 to 4 tests performed on independent regions of the membrane was recorded. Means and SDs were calculated through the gestational age ranges of less than 32, 32 to 36, or 37 weeks or longer. Linear regression analysis was performed across gestational age after grouping data by labor and mode of delivery. RESULTS: There were trends toward decreasing puncture force with gestational age for both chorioamnion and amnion for both vaginal deliveries and cesarean sections. The trends were significant by linear regression for labored deliveries but not unlabored cesarean sections for both chorioamnion and amnion alone. There was no trend in chorion puncture force with either gestational age or delivery mode and the mean puncture force values were, on average, half those for the amnion. CONCLUSION: The amnion is significantly stronger than the chorion when subjected to biaxial strength testing. The amnion but not the chorion is significantly affected by the chemical and mechanical changes during gestation and the labor process. These data will help direct future studies on the effects of clinical and molecular modulators of inflammation on membrane rupture thresholds with special emphasis on the biochemical and structural changes in the amnion.

Adult↗