[Measurement of sulcus fluid as a diagnostic measure in periodontal diseases. (I). Presence, composition and measurement methods of sulcus fluid].
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Examined the predictive validity and construct equivalence of the three major procedures used to measure assertive behavior: Self-report, behavioral role-playing, and in-vivo assessment. Seventy-five Ss, who spanned the range of assertiveness, completed two self-report measures of assertiveness, the Rathus Assertiveness Scale (RAS) and the College Self-Expression Scale (CSES); two scales from the Endler S-R Inventory of General Trait Anxiousness, the interpersonal and general anxiety scales; eight role-playing situations that involved the expression of positive and negative assertiveness; and a telephone in-vivo task. In general, the study revealed the following: (1) assertiveness measures are task-dependent in that there was more overlap within task than between tasks; (2) there is a moderate degree of correspondence between self-report and role-playing measures, although this was true only for negative assertion; (3) positive and negative assertion do not appear to have the same topography of responding; and (4) there appears to be no consistent relationship between the in-vivo measure and any other type of assertiveness measure.
A novel quasi-continuous on-line measuring technique for shaken microtiter plates is presented. Light scattering as well as intracellular and/or protein fluorescence (e.g. NADH, YFP) is measured during the shaking procedure, thus allowing a process monitoring of 96 different simultaneous cultures in a microtiter plate. In contrast to existing measurement techniques, the shaking process does not have to be stopped to take the measurements, thus avoiding the corresponding interruption of the cultures' oxygen supply and any unpredictable effects on the cultures. Experiments were conducted with E. coli in LB, TB, and MOPS minimal medium and V. natriegens in modified LB and TB media. Intensity curves of scattered light and NADH fluorescence were used to distinguish different lag phases, growth velocities, or inoculation densities. Data from this new method corresponded well to the off-line measured optical densities and to the oxygen transfer rates of cultures run in simultaneously conducted shake flask experiments at equivalent oxygen transfer capacities. With the aid of yellow fluorescence protein fused to interleukin-6 the optimal induction time of an expressing E. coli strain could be determined by on-line monitoring of product formation. Thus, this measuring technique enables the researcher to evaluate and to discriminate different cultures on a screening level and to improve screening conditions, process development and scale-up.
The incorporation of informal care into economic evaluations of health care is troublesome. The debate focuses on the valuation of time spent on informal caregiving, while time measurement, a related and may be even a more important issue, tends to be neglected. Valid time measurement is a necessary condition for the valuation of informal care. In this paper, two methods of time measurement are compared and evaluated: the diary, which is considered the gold standard, and the recall method, which is applied more often. The main objective of this comparison is to explore the validity of the measurement of time spent on providing informal care. In addition, this paper gives empirical evidence regarding the measurement of joint production and the separation between 'normal' housework and additional housework due to the care demands of the care recipients. Finally, the test-retest stability for the recall method is assessed. A total of 199 persons giving informal care to a heterogeneous population of care recipients completed the diary and the recall questionnaire. Corrected for joint production, informal caregivers spent almost 5.8 h a day on providing informal care. If one assumes that respondents take into account joint production when completing the recall questionnaire, the recall method is a valid instrument to measure time spent on providing informal care compared to the diary. Otherwise, the recall method is likely to overestimate the time spent on providing informal care. Moreover, the recall method proves to be unstable over time. This could be due to learning effects from completing a diary.
Measurements of variceal pressure with a noninvasive endoscopic pressure gauge and by direct variceal puncture were performed in 20 cirrhotic patients with portal hypertension in the course of the first session of therapeutic sclerotherapy following an episode of variceal bleeding. Endoscopic gauge measurements of the pressure of esophageal varices gave similar values (15.5 +/- 2.7 mm Hg) than measurements by variceal puncture (15.4 +/- 2.4 mm Hg; not statistically significant), and there was a highly significant linear correlation between both measurements (r = 0.9, p less than 0.001). Azygos blood flow, that was markedly increased in these patients (852 +/- 399 ml per min), was directly related to variceal pressure (r = 0.73, p less than 0.01). Variceal pressure was significantly lower than portal pressure (18.8 +/- 5.0 mm Hg) (p less than 0.05), indicating that measurements of variceal pressure cannot substitute measurements of portal pressure. The study demonstrates that the noninvasive endoscopic gauge technique allows an accurate estimation of variceal pressure in patients with portal hypertension. This technique may provide additional useful information in the evaluation of portal hypertension as well as on the mechanism of variceal bleeding.
Neonatal anthropometry, including timed skinfold measurements, was performed on 55 products of selected pregnancies. These skinfold measurements were compared with published standards of measurements obtained by similar techniques. Values outside the 3rd percentile to 97th percentile range were overlaid on the birth weight/menstrual age relationship of these subjects. Seven of 10 subjects with the lowest midtriceps skinfolds weighed more than 2500 g at birth (2 more than 3500 g) and 2 of 4 with the largest midtriceps skinfold had birth weights less than 4000 g. This comparison emphasizes the imprecision of birth weight as a measure of quality of fetal growth. Since skinfold thickness measurement is cumbersome for clinical use, other neonatal measures that may be more readily available to the clinician were examined for correlation with skinfolds. Simple birth weight/crown-heel length ratio was found to have the closest relationship of the parameters examined. Although estimated fetal weight was found to be the ultrasonography-derived parameter best correlated with skinfold thickness, ultrasonography discriminated poorly between babies with normal and low skinfolds. Low skinfold thickness predicted thermal vulnerability in the nursery better than did birth weight.
Changes in cerebral blood flow (CBF) induced by Acetazolamide (ACZ) were measured using dynamic susceptibility contrast MRI (DSC-MRI) with both spin echo (SE) EPI and gradient echo (GE) EPI, and related to changes in internal carotid artery (ICA) flow measured by phase-mapping. Also examined was the effect of repeated bolus injections. CBF, cerebral blood volume (CBV), and mean transit time (MTT) were calculated by singular value decomposition (SVD) and by deconvolution using an exponential function as kernel. The results showed no dependency on calculation method. GE-EPI measured a significant increase in CBF and CBV in response to ACZ, while SE-EPI measured a significant increase in CBV and MTT. CBV and MTT change measured by SE-EPI was sensitive to previous bolus injections. There was a significant linear relation between change in CBF measured by GE-EPI and change in ICA flow. In conclusion, GE-EPI under the present condition was superior to SE-EPI in monitoring cerebral vascular changes.
In the foregoing we have tried to give a broad survey of the parameters which are of importance for irradiation experiments and which can be measured by NMR. Since it is the temperature change during irradiation that is of immediate interest, we have tried to emphasize the ways in which this quantity can be measured. This has shown that temperature measurement by means of the chemical shift has experimental limits as well as the fact that overlapping signals may cause problems. Hence, more experiments must be carried out in order to clarify the possibilities of its use. Although experimentally this is no easy task, it is feasible. In particular, the possibility of determining the temperature by external markers introduced into the tissue should be studied. The development of new nontoxic thermometric compounds with greater sensitivity would be a great step forward. The possibility of determining the temperature through the relaxation times of water represents a real alternative, especially since this can be carried out by low-resolution NMR. Additional experiments are necessary in order to see whether the sensitivity attainable is satisfactory. Chemical exchange processes and changes in metabolite concentration could also be used to measure the temperature or the effect of an irradiation experiment. In conclusion, one can say that the measurement of control parameters (especially for irradiation experiments by means of NMR) represents a difficult experimental problem. It does not promise success in all cases but probably represents the only noninvasive measurement possibility. For this reason, wide-ranging experiments should be initiated in order to obtain definitive results.
The paper reports the development of an electronic system of milk temperature measurement and the results of investigations into the influence of milk yield, milk flow and ambient temperature on milk temperature. The milk and body temperatures of randomly selected multiparous Friesian cows were recorded at afternoon milkings. Temperature was measured by bead thermistors housed in perspex probes from which a digital read-out with an accuracy of +/- 0.1 degree C was obtained. Milk temperature was measured at four sites: the short milk tube (SMT), claw piece (CT), and the beginning (BLT) and end of the long milk tube (ELT) with readings being taken every 30 s from the commencement of milking. Body temperature measured with a probe in the vagina (VT) 38.85 +/- 0.02 degrees C) was significantly higher than milk temperature at any of the four sites although a significant positive correlation existed between milk and body temperature. Milk temperature measured at each site decreased with distance from the cows (SMT: 38.64 +/- 0.03 degrees C, ELT: 37.92 +/- 0.04 degrees C). The difference between body and milk temperature was greatest in cows in which milk flow rates were below average (less than 1.37 kg/min) and/or milk yields were below average (less than 7.82 kg/milking). Milk temperature sites SMT and CT were least affected by variation in milk yield or flow, and showed the closest relationship between maximum milk temperature and body temperature. Milk temperature measurement was most reliable when taken during the full flow of milk.
The accuracy of indirect oscillometric blood pressure measurements has been evaluated in 32 infants up to 11 months of age undergoing heart surgery. In a number of 1029 simultaneous measurements the indirect blood pressure was compared with the direct value obtained from a radial artery catheter. Cuffs of different sizes were applied. The main results were as follows: Regarding the ratio of cuff width to arm circumference, the best correlation between oscillometric and direct blood pressure measurements was obtained with a ratio of 0.38-0.41. The value of indirect blood pressure measurements depends on the absolute height of the blood pressure. In low blood pressure there is a tendency to underestimate and in high blood pressure there is a tendency to overestimate by the oscillometric blood pressure measurement. By applying an appropriate cuff size and by using our diagrams it should be possible to derive a direct value for the blood pressure on the basis of indirect oscillometric blood pressure measurements.
Tissue hardness is related to tissue composition, and this is often changed by disease. It is therefore of interest to measure the hardness in an objective and non-invasive way. A tactile sensor based on a vibrating piezoelectric ceramic element in a feedback loop is described. When the sensor touches an object it produces a frequency shift related to the hardness of the object. The aim of this study was to develop an in vitro hardness measurement method using a catheter type version of the sensor. The method was evaluated in an established silicone tissue model and on human prostate tissue in vitro. A linear relationship was found with a high degree of explanation (R2 = 0.98) between a cone penetration hardness standard (DIN ISO 2137) applied to the silicone model and the corresponding frequency shift. The results from measurements on a human prostate tissue sample, fixed with formalin, showed that the relative hardness measured with the tactile sensor correlated (R = -0.96, p < 0.001, N = 60) with the proposed hardness related to the histological composition of the prostate tissue. The results indicated that hardness of prostate tissue, and maybe hardness of human tissue in general, can be expressed according to the cone penetration standard and that the hardness can be measured with this tactile sensory system. These findings hold the promise of further development of a non-invasive tool for hardness measurement in a clinical situation.
Previous studies comparing axial and appendicular skeleton have shown that trabecular bone loss is greater than cortical bone loss. However, whether the same difference exists between the trabecular and the cortical compartments of the vertebral body remains to be determined. In this study, we used quantitative computer tomography (QCT) to simultaneously measure the cortical rim of the vertebral body as well as trabecular bone. In 99 Caucasian women (mean age 53.8 +/- 13.0 years, range 26-79 years) we found a significant correlation between cortical mineral content (BMCC) and both single (SE) and dual energy (DE) trabecular mineral content (BMCT) (r = 0.62, P less than 0.0001 for both regressions). The cross-sectional rates of bone loss per year were 1.32%, 1.16%, and 0.59% for SE-BMCT, DE-BMCT, and BMCC, respectively. BMCC decreased at a rate that was 45-51% that of SE-BMCT and DE-BMCT, respectively. Our results indicate that (1) QCT may provide a useful means to selectively measure cortical density in vertebral bodies; (2) the decrease of cortical density over time in the spine appears to have been underestimated previously by extrapolation from appendicular bone measurements; (3) because measurements of the entire vertebral body (exclusive of the posterior elements) may provide information that is more representative of spine changes with age, a measurement that includes both areas might be more useful than one measuring only the trabecular region.
Investigators have found that dual-energy X-ray absorptiometry (DXA) of areal bone mineral density (BMD) values in HIV-1 infected children and adolescents are reduced. Volumetric bone density (BD) measured by quantitative computed tomography (CT) in this population has not been studied. This study was designed to evaluate bone measurements in HIV-1 infected children and adolescents using DXA and CT. Fifty-eight children and adolescents (32 females and 26 males with a mean age +/- SD of 12.0+/-3.9 years, age range 5.0-19.4 years) with perinatally acquired HIV-1 infection underwent simultaneous bone area and density evaluation by DXA and CT. Height and weight measurements as well as pubertal assessment were performed on the same day. All but four subjects were receiving highly active antiretroviral therapy (HAART). Subjects were matched with healthy children and adolescents for age, gender, and ethnicity. HIV-1 infected children were significantly shorter (P <0.001), lighter (P <0.005), and had delayed puberty (P <0.001) compared to controls. Using DXA, HIV-1 infected subjects had significantly less bone area (P <0.001), bone mineral content (BMC) (P <0.005), and BMD (P <0.05) at the vertebral level compared to controls. In addition, bone area (P <0.001), BMC (P <0.001), and BMD (P <0.005) of the whole body were also reduced relative to controls. In contrast, using CT, HIV-1 infected subjects had similar vertebral BD compared to controls, but smaller vertebral height and cross-sectional area (CSA) (P =0.01 and P <0.005, respectively). DXA Z-scores provided values significantly lower than CT Z-scores in the HIV-1 infected population (P <0.01). After accounting for weight and vertebral height, stepwise multiple regression demonstrated that the prediction of CT BD values of L1 to L3 from DXA values of these vertebrae was significantly improved. HIV-1 infected children and adolescents have lower vertebral and whole body BMC and BMD DXA measures. In contrast, vertebral BD measurements by CT are normal. The lower bone measurements were primarily due to the decreased bone and body size of the HIV-1 subjects.
The performance of quantitative ultrasound (QUS) measurements of the tibia and calcaneus was studied in 109 elderly people (age range 65-87 years). Broadband ultrasound attenuation (BUA) and speed of sound (SOS) were measured at the calcaneus and SOS was assessed at the tibia. Short-term precision of tibial QUS was studied in 16 volunteers. The coefficient of variation (CV) was 0.4% and the standardized CV (sCV) was 4.4%. We compared the calcaneal and tibial QUS measurements with bone mineral density (BMD) measurements of the lumbar spine, femoral neck, trochanter and total body assessed by dual-energy X-ray absorptiometry (DXA). Calcaneal QUS correlated better with BMD at various skeletal sites than tibial QUS. Calcaneal BUA showed higher correlations with BMD values of the lumbar spine, femoral neck, trochanter and total body than calcaneal and tibial SOS (r = 0.48-0.64, r = 0.30-0.47, r = 0.35-0.47, respectively; p < 0.001). Body weight modified the relationships between calcaneal and tibial QUS and BMD measurements of the hip. Higher body weight was associated with higher BMD values at the femoral neck and trochanter for the same calcaneal and tibial QUS values. After adjustments for body weight correlations of tibial and calcaneal QUS with BMD improved and were very similar. This suggests that correction for body weight is important and could add to the predictive value of QUS measurements.
PURPOSE: The aim of the study was to compare the accuracy and the reproducibility of scotopic pupil measurements using two different methods. PATIENTS AND METHODS: We developed a simple test to measure scotopic pupil diameters using a narrow slit of light through a green filter of the Haag-Streit slitlamp. A total of 100 eyes from 50 refractive surgery candidates were prospectively examined by 2 independent investigators using both the Colvard pupilometer (Oasis/USA) and Sekundo's slitlamp green light test. Results were compared using all pairwise multiple comparison procedures (Student-Newman-Keuls method, SigmaStat/Jandel Scientific). The mean age of the patients was 36.3 years with a male:female ratio of 16:34. The colour of the iris was considered blue for 36 individuals and brown for the remainder. RESULTS: Reproducibility: the right eye mean pupil diameter using Sekundo's method was 6.4 mm (+/-0.9) measured by both the first (Slit 1R) and the second (Slit 2R) investigator. The left eye mean pupil diameter was 6.5 mm (+/-1) (Slit 1L) and 6.35 mm (+/-1) (Slit 2L), respectively. The following measurements were obtained with the Colvard pupillometer: (Colv1R)=6.25+/-0.85 mm, (Colv2R)=5.99+/-1 mm, (Colv1L)=6.15+/-0.91 mm, (Colv2L)=6.05+/-0.9 mm. There were no statistically significant differences between the two investigators within the same method of examination. Comparability:The data of both investigators were combined to form 4 groups: (Slit R)=6.4+/-0.96 mm, (Slit L)=6.4+/-1 mm, (Colv R)=6.05+/-0.9 mm, (Colv L)=6.1+/-0.93 mm. There was a significant difference ( p=0.024) between the two methods for both right and left eyes. Particularly for large pupils, the slitlamp green light measurements were significantly higher (up to 0.35 mm) than those with Colvard's device. CONCLUSIONS: The slitlamp green light test provides similar reproducibility for the measurement of the scotopic pupil diameter as the commercially available Colvard pupilometer.
BACKGROUND: The non-contact specular microscope has become the method of choice for a quick, accurate and non-invasive assessment of central corneal thickness (CCT), which is an important variable to monitor before and after refractive surgery. The consistency of the results produced by such widely used methods/equipment must be assessed to determine their reliability. The purpose of this study was to assess within- and between-observer repeatability of, and to determine if a systematic bias exists in the measurements made by, the Topcon SP2000P specular microscope. METHODS: The CCT of the right eyes of 70 adult subjects, divided equally between men and women, was assessed on two separate occasions (4-7 days apart) by each of two examiners using the low-intensity auto mode of the SP2000P specular microscope. RESULTS: The average CCT values for men and women, measured by one observer, were 0.52+/-0.03 mm (mean +/- SD) and 0.52+/-0.04 mm, respectively. The average for the entire sample was 0.52+/-0.04 mm. Within- and between-observer repeatability were assessed by plotting the mean difference (for each subject) between two readings made by the same observer or one each by both observers against the combined average CCT reading of both sessions; the mean difference between two sets of observations was not significantly different from zero (P<0.05). For the first observer, the 95% limits of repeatability were between -0.015 and 0.017 mm. For the second observer, the 95% limits of repeatability were between -0.018 and 0.018 mm. For the between-observer repeatability, the 95% limits of agreement were between -0.016 and 0.016 mm. For both within- and between-observer repeatability, we found no systematic bias of the mean difference with the average CCT reading. CONCLUSION: The within- and between-observer limits of agreement we found were similar to those previously reported for the Topcon SP2000P specular microscope; the range of the 95% limits of repeatability were within +/-1 SD of the average CCT reading for both sessions. We suggest that a technique be considered reliable if: (1) the mean difference between two measurements does not vary significantly from zero, (2) there is no systematic bias of the mean difference with the magnitude of the measured quantity and (3) the error inherent in a measurement technique is within +/-1 SD of the average measurement of the two sessions.
BACKGROUND: Multi-item health status measures can be lengthy, expensive, and burdensome to collect. Single-item measures may be an alternative. We compared measurement properties of two single-item, general self-rated health (GSRH) questions to assess how well they captured information in a validated, multi-item instrument. METHODS: We administered a general health survey (SF-12V) that included "standard" and "comparative" forms of a GSRH. We repeated the survey two weeks later to the same 75 medically stable outpatients to test for GSRH reproducibility, reliability, and validity using SF-12V Physical Functioning and Emotional Health subscales as a reference. RESULTS: At each survey administration, the two GSRH questions demonstrated good alternate forms reliability (first administration: r = 0.74, p < 0.001; second administration: r = 0.74, p < 0.001) and good reproducibility ("standard": ICC 0.69; "comparative": ICC 0.85). Both GSRH items correlated with physical functioning ("standard": r = 0.66; "comparative": r = 0.56) and emotional health measures ("standard": r = 0.65; "comparative": r = 0.59). Mean subscale measures associated with responses in each GSRH category were significantly different (ANOVA, p < 0.001), indicating strong discriminant scale performance. CONCLUSIONS: Our single-item, GSRH questions demonstrated good reproducibility, reliability, and strong concurrent and discriminant scale performance with an established health status measure.