Some indirect estimates of fertility from 1980 census data in Kuwait.
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Age Factors↗
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Results for “Indirect Estimation Technics”
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Maternal mortality in rural Zambia.
OBJECTIVE: To assess maternal mortality. DESIGN: Sisterhood method survey and hospital data. SETTING: Communities in Kalabo District, a very remote rural area in western Zambia; Kalabo District Hospital. RESULTS: The number of respondents in the sisterhood method survey was 1,978. The estimated maternal mortality ratio derived from this survey was 1,238 per 100,000 live births. The hospital study involved 2,474 deliveries of 2,374 live babies. The official number of maternal deaths was 13. Further investigation of files revealed an additional 15 maternal deaths, bringing the institutional maternal mortality rate from 548 to 1,179 per 100,000 live births. The major causes of direct maternal deaths were obstructed labor and sepsis. In 71% of all cases substandard care factors contributed. CONCLUSIONS: Maternal mortality in rural Zambia is among the highest as reported in the world. Official hospital data tend to underestimate maternal mortality in the community due to underreporting. The sisterhood method survey is an efficient indirect method to assess maternal mortality in rural areas of developing countries.
Adolescent↗
[Indirect estimation of the maximal aerobic power of a male and female population from Brussels aged 6 to 23 years. Comparison with a direct technic for measuring maximal oxygen consumption].
Validation of the maximal multistage 20 m shuttle run test with 1 min steps has been compared with a stepwise load increase on a bicycle ergometer among 201 male and female subjects ranging from 14 to 30 years. A slight underestimation of VO2 max (5.2%) amounting to 2.71 ml . min-1 . kg-1 was observed for the multistage shuttle test as compared to the bicycle test (r = 0.72). The analysis of the biological values collected after exercise does not show major differences between the two tests (plasma lactate, urinary total protein and albumin, creatinine). The renal handling of plasma proteins appears to be equally disturbed under the influence of exhaustive exercise. Maximal aerobic power regularly increases with age in both sexes, being more pronounced however for boys (1.16 to 3.37 l . min-1) than for girls (1.17 to 2.43 l . min-1) from 6 to 20 years old. Boys nearly sustain 50 ml . min-1 . kg-1 throughout childhood. On the contrary, from 8 years on girls progressively reduce their VO2 max down to 37.1 ml . min-1 . kg-1 at the age of 19. The decrease is more pronounced during the 11-16 years period. The present results constitute tentative norms on 1,025 brussels male and female subjects ranging from 6 to 23 years.
Adolescent↗
Quantitative assessment of Ascaris lumbricoides infection in school children from a slum in Visakhapatnam, south India.
An epidemiological study was conducted on 217 school children aged between 7-13 years, from Relliveedhi a slum in Visakhapatnam, Andhra Pradesh, south India, during August 1993 to August 1994. The children belonged to a socioeconomically backward community-parental occupation being fishing or waged labor. Intensity and prevalence estimations for Ascaris lumbricoides were done indirectly by formalin-ethyl-acetate sedimentation technic and directly by worm expulsions following albendazole administration at a single oral dose of 400 mg/child. Prevalence rate was 73% while the intensity of infection ranged between low to moderate. Boys had severe infection than girls due to their outdoor activities and behavioral habits. Nine year old children had the highest prevalence rates. Mean Ascaris worm intensity was 2.2 (+/-1.91) with an over-dispersed distribution of the parasite in the host population. Reinfection study over a period of nine month showed that the prevalence rates exceeded the pre-intervention level but the intensity of infection was very low. Dual species intensity correlation between Ascaris and Trichuris was consistently strong.
Adolescent↗
Estimating the employment and earnings costs of mental illness: recent developments in the United States.
Substantial attention has recently been focused on both the prevalence and consequences of mental illness. Generally, public interest in the costs of mental illness has been limited to the direct costs of treating the mentally ill. In this paper, we consider the magnitude and importance of a major component of the indirect costs of mental illness: employment and earnings losses. We first describe the technical difficulties involved in estimating these costs. We then describe new data and recent advances in the United States that have improved our ability to make such estimates. Our conclusions from the recent research are that each year in the United States 5-6 million workers between the ages of 16 and 54 lose, fail to seek, or cannot find employment as a consequence of mental illness. Among those who do work, we estimate that mental illness decreases annual income by an amount between $3,500 and $6,000. We then discuss an emerging challenge to the traditional method for arriving at such estimates: the friction cost approach. We describe both the conceptual and technical differences between the friction cost method and the traditional human capital approach. We conclude that while economic context has much to do with whether one relies on human capital or friction cost estimates, each can offer useful information about labor market losses due to mental illness.
Adolescent↗
Mathematical models and their application in body composition research.
Mathematical models are a means of formalizing the knowledge on living systems obtained in clinical physiology and theoretical biophysics. They allow the actual processes in living systems to be described and the mechanisms of these systems to be evaluated. The study of body composition strives to quantitatively evaluate intrinsic body compartments and to obtain important information on the nutritional and energy requirements of healthy persons and those with various pathologies. Although there has been great progress in the development of sophisticated instruments for body composition research, it is not always possible to directly measure certain body compartments (e. g. intracellular water and fat mass) because of either technical difficulties or for ethical reasons. Therefore, mathematical models, which can potentially estimate these compartments indirectly, may be a viable alternative. In this paper, we describe the various advances in the use of mathematical models for body composition research.
Body Composition↗
Estimation of available energy of dietary fibres by indirect calorimetry in rats.
BACKGROUND: Knowledge of energetic availability of dietary fibres is important for human nutrition. But up to now results are often different and depend on the methods used. Estimation of metabolisable energy of dietary fibres (mainly by balance technique) is a time-consuming procedure and needs special technical effort. AIM OF THE STUDY: Validation of the experimental design for short-term studies by using indirect calorimetry with feeding below maintenance requirement to evaluate the energetic availability of dietary fibres and their influence on absorption velocity of carbohydrates (CHO). METHODS: Energy expenditure and CHO oxidation (including short-chain fatty acids as fermentation products) were estimated in Wistar rats over 23 h after being fed a basal diet for the first day (300 KJ/kg0.75, 20% protein, 3% fat, 77% CHO) followed by supplementation with either microcrystalline cellulose, the soluble rye fibre arabinoxylan, apple pectin, amylomaize starch (with 48% of resistant starch) or gelatinised wheat starch (200 KJ/kg0.75 each) as control for the following days. Energetic availability was determined by comparing the increase of CHO oxidation after addition of gelatinised wheat starch with that of the dietary fibres tested. RESULTS: In comparison to wheat starch (100%), the following energetic availability of the dietary fibres was found: microcrystalline cellulose 14%, arabinoxylan 33%, pectin 39%, amylomaize starch 62%. The time-course of CHO oxidation indicated that microcrystalline cellulose enhances, whereas the soluble rye fibre slows down the velocity of CHO absorption due to the different consistency of the intestinal contents modified by the kind and properties of the used dietary fibres. After intake of arabinoxylan or pectin, CHO oxidation remained at a higher level during the experimental period elucidating an increased activity of fermentation to short-chain fatty acids. CONCLUSIONS: Short-term experiments in rats using indirect calorimetry are a suitable method for comparative estimation of the energetic availability of dietary fibres. Results are partly in agreement with values estimated by long-term in vivo methods.
Animals↗
Prevalence rates of Borrelia burgdorferi sensu lato in host-seeking Ixodes ricinus ticks in Europe.
Borrelia burgdorferi sensu lato spirochetes have been found in all examined Ixodes ricinus (L.) populations in Europe. The overall mean proportions of unfed I. ricinus infected with B. burgdorferi s.l. were 1.9% (range 0-11%), 10.8% (2-43%) and 17.4% (3-58%) for larvae (n = 5699), nymphs (n = 48,804) and adults (n = 41,666), respectively. However, the results varied according to the method used. Cultivation in BSK medium is the least sensitive technique (an average of 11% adult ticks found infected), whereas polymerase chain reaction detecting spirochetal DNA is probably the most sensitive method (29% adults found infected). Microscopic methods (dark field, phase contrast, direct or indirect fluorescence) are generally comparable to each other (17-20% adults found infected) and should be regarded as standard procedures because they also make possible a quantitative estimation of spirochetes in the vector. Some technical problems of these methods are discussed.
Animals↗
[Demonstration of human spermatozoa chromosomes in a heterospecific system: technical difficulties].
The incidence of chromosomal abnormalities at conception has been estimated to be very high about 40%; these estimations have been made on indirect evidence provided by karyotyping spontaneous abortions products. Now direct evidence is available, consisting in sperm chromosome analysis by using fertilization of zona-free eggs of the golden hamster. In our experience 175 assays have been performed with modifications of the technique described by Martin et al. (1982) and by Brandriff et al. (1984). Consistent results are obtained since the last 30 assays, using for the first time an R banding technique. Chromosomal analysis of 48 spermatozoa from 7 normal males is reported. The frequency of abnormal sperm complements (21%) is higher than reported by previous reports.
Animals↗
Comparison of three methods of determining oxygen consumption and resting energy expenditure.
Resting energy expenditure (REE) in intensive care unit patients was evaluated by three methods--indirect calorimetry (REE-IC), Fick equation (REE-F), and estimation from the Harris-Benedict equation (REE-HB). The mean REE-IC and REE-F values did not differ significantly. However, both values were significantly higher than the REE-HB. The present study indicates that a reasonably accurate estimate of the REE can be obtained from data available by Swan-Ganz catheterization. The Fick method is technically simpler to perform and less expensive than indirect calorimetry. The invasive nature of Swan-Ganz catheterization is a major disadvantage. However, right-sided heart catheterization frequently is required for the management of intensive care unit patients. For them, REE-F appears to be a reasonable alternative.
Aged↗
[Comparison of Narula's technic of direct and estimated sinoatrial conduction at increasing rates in normal subjects].
Twenty eight normal subjects in sinus rhythm underwent direct measurement of sinoatrial conduction time (SACTD) by sinus node potential recordings (SNP) and indirect evaluation by Strauss (SACTS) and Narula's methods (SACTN) using the extrastimulus technique. Stimulation in Narula's method was undertaken at three different rates, 3, 6 and 9 beats per minute faster than the spontaneous rate of the subject (SACTN3, SACTN6, SACTN9). The mean values (+/- SD) were as follows: SACTD 84 +/- 18, SACTN3 85 +/- 29, SACTN6 96 +/- 33, SACTN9 101 +/- 36. The mean value of the SACTD was significantly lower than that of the SACTN9 (p less than 0,01) but there were no significant differences between SACTD and SACTN3 and SACTN6. The three values of the SACTN were closely related to each other but not to the values of the SACTD.
Action Potentials↗
The detection of double stranded DNA antibody using human metaphase chromosomes.
Double stranded native DNA (dsDNA) antibody detection is important in the diagnosis and management of patients with Systemic Lupus Erythematosus (SLE). Current radioimmunoassay and haemagglutination assays for DNA antibodies are technically complicated or show considerable inter-laboratory variation. A simple inexpensive indirect immunofluorescence method using fixed human metaphase chromosomes for DNA antibody estimation is described. The method has been compared with the Farr radioimmunoassay and Crithidia luciliae techniques. The metaphase test showed 100% correlation with a positive Farr assay in 38 of 373 routine DNA antibody estimations. Simultaneous testing using Crithidia showed 84% correlation, indicating greater sensitivity of the metaphase method. Enzyme treatment of metaphase and Crithidia substrate abolished reactivity on DNAase treated substrate alone, and DNA specific fluorescent staining further confirmed metaphase substrate specificity. The metaphase test appears simple, specific, of greater sensitivity, easily read, and can be utilized in large or small laboratories to determine DNA antibodies and their subclasses.
Antibodies, Antinuclear↗
Indirect calorimetry.
Indirect calorimetry can be a useful tool to define nutritional status, determine nutritional requirements, and assess response to nutritional interventions. Measurements of oxygen consumption and carbon dioxide production may be used to determine cardiac output and work of breathing, and estimate the components of minute ventilation. An understanding of the potential technical and physiological pitfalls is necessary to obtain meaningful and useful information.
Acid-Base Equilibrium↗
The use of IgH fingerprinting and ASO-dependent PCR for the investigation of residual disease (MRD) in ALL.
In acute lymphoblastic leukaemia (ALL), investigation of minimal residual disease by conventional morphology and immunology fails to detect levels of residual disease of < 1 leukaemic in 10-100 normal cells. The use of polymerase chain reaction (PCR) to exploit the diversity of the complementarity determining region (CDR) and immunoglobulin variable heavy chain (VH) family specific usage has greatly improved the sensitivity up to one leukaemic cell in 10(5)-10(6) normal bone marrow cells. Here we report on a prospective study of 14 patients with ALL of B-cell lineage by using a combined PCR approach which estimates levels of disease between 1:10(3) and 1:10(5). The sequential use of allele-specific oligoprimer (ASO) independent tests (using framework 1. FR1 and 3, FR3 primers with a JH consensus primer, sensitivity up to 1:5 x 10(3)) and ASO-dependent PCR (sensitivity up to 1:10(5)) assays were applied to 64 bone marrow (BM) follow-up samples in a sequential array of tests. Results presented in this study indicate high concordance of MRD among different tests for samples with level of residual disease > 1:5 x 10(3). Consequently, samples positive by the FR1 and FR3 fingerprinting tests were confirmed by the more sensitive ASO-dependent tests, as expected. However, the ASO-dependent assays revealed levels of disease undetected by the FR1 and FR3 test. Although a higher level of sensitivity is provided by the ASO-dependent tests, the FR1 and FR3 fingerprinting tests allow MRD investigation in patients with oligoclonal B cell proliferations, CDR3 region of size < 15 bp or with ASO primers unsuitable for PCR investigation on technical grounds (i.e. background signal). If a sequential order of investigation from less (e.g. FR1 and FR3 fingerprinting) to more sensitive tests (ASO-dependent) is applied, an indirect estimate of MRD is obtained for patients with level of disease < 1:10(3).
Adolescent↗
The analysis of driving mode influence on energy dissipation in pneumatic artificial heart chambers.
The energy dissipated in blood or on a total artificial heart (TAH) chamber's elements directly or indirectly decreases the biological or technical safety of the TAH's work. The energetic analysis of the Polish total artificial heart (POLTAH) external work with the objective of estimating the valve and membrane roles in energy dissipation has been performed. The simulation of left and right artificial heart chamber work under physiological conditions using a self-constructed physical model of the circulatory system has been performed for the full systole percent and frequency range and for different valves. The total energy dissipated on valves equals 15-30% of the chambers' work value. Energy losses on valves are influenced by the driving mode. The usage of inappropriate systolic and diastolic times increases the value of the energy dissipated on the membrane and on valves in the overall energy balance. The absolute value of the energy dissipated on the valves increases with the increase of the cycle time and depends on the valve type. The energy dissipated on the outlet valve decreases with the frequency (if the remaining driving parameters are kept constant) and for 150 bpm is nearly 3 times lower than that for 30 bpm. The energy dissipated on the membrane equals 10-50% of the TAH's work during systole, depending on the driving parameters. The filling process is assisted by the pressure from the atrium, and a great amount of energy during the diastolic period is consumed by the start of the membrane movement. We have also estimated the influence of the driving parameters on the valves' functions, measuring the acoustic wave intensity. The conclusions drawn are of a general character; they are applicable to all membrane, pneumatically powered blood pumps.
Acoustics↗
On problems of calculating energy expenditure and substrate utilization from respiratory exchange data.
Indirect calorimetry based on respiratory exchange measurement has been successfully used from the beginning of the century to obtain an estimate of heat production (energy expenditure) in human subjects and animals. The errors inherent to this classical technique can stem from various sources: 1) model of calculation and assumptions, 2) calorimetric factors used, 3) technical factors and 4) human factors. The physiological and biochemical factors influencing the interpretation of calorimetric data include a change in the size of the bicarbonate and urea pools and the accumulation or loss (via breath, urine or sweat) of intermediary metabolites (gluconeogenesis, ketogenesis). More recently, respiratory gas exchange data have been used to estimate substrate utilization rates in various physiological and metabolic situations (fasting, post-prandial state, etc.). It should be recalled that indirect calorimetry provides an index of overall substrate disappearance rates. This is incorrectly assumed to be equivalent to substrate "oxidation" rates. Unfortunately, there is no adequate golden standard to validate whole body substrate "oxidation" rates, and this contrasts to the "validation" of heat production by indirect calorimetry, through use of direct calorimetry under strict thermal equilibrium conditions. Tracer techniques using stable (or radioactive) isotopes, represent an independent way of assessing substrate utilization rates. When carbohydrate metabolism is measured with both techniques, indirect calorimetry generally provides consistent glucose "oxidation" rates as compared to isotopic tracers, but only when certain metabolic processes (such as gluconeogenesis and lipogenesis) are minimal or / and when the respiratory quotients are not at the extreme of the physiological range. However, it is believed that the tracer techniques underestimate true glucose "oxidation" rates due to the failure to account for glycogenolysis in the tissue storing glucose, since this escapes the systemic circulation. A major advantage of isotopic techniques is that they are able to estimate (given certain assumptions) various metabolic processes (such as gluconeogenesis) in a noninvasive way. Furthermore when, in addition to the 3 macronutrients, a fourth substrate is administered (such as ethanol), isotopic quantification of substrate "oxidation" allows one to eliminate the inherent assumptions made by indirect calorimetry. In conclusion, isotopic tracers techniques and indirect calorimetry should be considered as complementary techniques, in particular since the tracer techniques require the measurement of carbon dioxide production obtained by indirect calorimetry. However, it should be kept in mind that the assessment of substrate oxidation by indirect calorimetry may involve large errors in particular over a short period of time. By indirect calorimetry, energy expenditure (heat production) is calculated with substantially less error than substrate oxidation rates.
Animals↗
Indirect calorimetry in critically ill patients: clinical applications and practical advice.
Indirect calorimetry is the method by which metabolic rate and substrate utilization are estimated in human beings starting from respiratory gas exchange measurements and urinary nitrogen excretion. This method is based on some models and assumptions that must be known and taken into consideration to correctly interpret the results obtained. Recent advances in technology and the availability of precise and portable metabolic carts have made this technique practical at the beside even in critically ill patients. It must be considered that, particularly in the ICU, there may be several sources of error and many technical difficulties in applying this methodology. Taking into account the relevant clinical studies related to the outcomes of critically ill patient, this article defines when the assessment of energy expenditure by indirect calorimetry may provide useful and valid information. Review of the literature suggests that the clinical application of indirect calorimetry in critically ill patients, although promising, requires further evaluation. Currently, the potential useful clinical applications of indirect calorimetry in this category of patients can be summarized as follows: (1) assessment of energy expenditure in patients who fail to adequately respond to the estimated nutritional needs; (2) assessment of energy expenditure in patients with single- or multiple-organ dysfunction who need prolonged ICU care and artificial nutritional support; (3) assessment of the effects induced by artificial nutrition on the cardiocirculatory and respiratory systems in mechanically ventilated patients with acute respiratory failure; and (4) monitoring of VO2 during weaning from mechanical ventilation.
Calorimetry, Indirect↗
Carotid arterial ultrasound scan imaging: A direct approach to stenosis measurement.
PURPOSE: Management decisions regarding carotid artery disease are critically dependent on stenosis but have been made difficult because of conflicting methods used to determine such stenosis. The increasing use of duplex ultrasound scanning has conventionally depended on Doppler velocity measurement, an indirect method for calculating carotid stenosis. Recent technical advances have improved the quality of B-mode/color-flow ultrasound scan imaging (USI). We tested prospectively whether USI was clinically effective as the primary criterion for estimating carotid stenosis. METHODS: Transverse and longitudinal USI, Doppler velocity, and arteriography data were obtained sequentially and independently for 713 carotid bifurcations. The internal carotid artery (ICA) residual lumen, the local outer diameter at the stenotic site, and the diameter distal to the bulb were measured in a representative USI longitudinal section. The peak systolic velocity and the end diastolic velocity (EDV) were measured at the stenosis. Local stenosis as determined with USI was compared with the x-ray arteriographic clinical radiology interpretation (XRI). As the primary method, radiologists compared the residual lumen with the distal ICA diameter, as recommended by the North American Symptomatic Carotid Endarterectomy Trial and the Asymptomatic Carotid Atherosclerosis Study. Analysis was by means of the USI positive predictive value (PPV) and negative predictive value (NPV) of the XRI findings, with the assumption that 80%, 70%, and 60% local stenosis with USI related to 70%, 60%, and 50% stenosis with XRI, respectively. RESULTS: All 56 ICA occlusions as determined with USI were confirmed with XRI. When the USI showed 80% to 99% stenosis, the PPV of the XRI showing 70% to 99% stenosis was 94% (116/123). Two ICAs that were shown to be severely diseased with USI appeared to be occluded with XRI. For <50% stenosis shown with USI, the prediction of <50% stenosis shown with XRI was 94% (253/269). For borderline stenosis in the 50% to 79% range with USI, the addition of velocity criteria to USI data improved both the PPV and the NPV. In the range of 70% to 79% stenosis with USI, the PPV improved from 82% (76/93) to 91% (53/58) for the subgroup with an EDV of more than 80 cm/s. For the range of 60% to 69% stenosis with USI, the PPV improved from 75% (71/95) to 95% (21/22) for the subgroup with an EDV of more than 80 cm/s. In the range of 50% to 59% stenosis with USI, the NPV improved from 69% (53/77) to 93% (14/15) for the subset with a peak systolic velocity of less than 100 cm/s. CONCLUSION: On the basis of the USI data alone, a prediction of arteriographic findings was possible at the 95% level for occlusion and severe stenosis and for ruling out hemodynamically significant stenosis. The addition of velocity data improved prediction in borderline degrees of stenosis. USI was effective for quantifying clinically significant degrees of stenosis.
Adult↗