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PubMed2003

Analysis of IgG subclasses and IgE antibodies across the clinical spectrum of bancroftian filariasis in an endemic area.

Analysis of immune response in individuals with different clinical manifestations living in filaria endemic area will be of interest to understand the immunological events associated with the disease development in filaria infected endemic population. The levels of four IgG subclasses and IgE antibodies against Brugia malayi microfilarial excretory-secretory (Bm mf ES) antigen as well as circulating filarial antigen level were evaluated in 84 individuals belonging to different groups in an endemic area for bancroftian filariasis. Microfilaraemics showed significantly elevated levels of IgG4 and IgG3 antibodies compared to endemic normals (P < 0.02). As many as 70% of this group were positive for IgG4 & IgG3 antibodies. While Acute filarial cases had pronounced IgG1 antibodies(P < 0.001), the Grade I chronic cases showed higher levels of IgG3 and IgG4 antibodies (P < 0.02), Occult filarial cases had higher levels of IgG4 and IgG3 (P < 0.02) and also of IgG4 antibodies (P < 0.001). IgE antibodies were found to be elevated in microfilaraemics as well as other clinical filarial groups. Circulating filarial antigen was detected in 95% of microfilaraemics, 60% of acute cases, 75% to 90% of different grades of chronic filarial cases, 100% of occult cases and none of the endemic normals.

Animals↗
PubMed1980

Analysis of brain weight. II. Adult brain weight in relation to body height, weight, and surface area.

Analysis of 1,261 adult subjects, ages 25 to 80 years, showed that there is a positive relationship between the brain weight and the body dimensions. The brain weight, however, increases at a slower rate than the body dimensions. There is indication that only a small portion of the brain varies with variation in the body dimensions. Among parameters, the brain weight correlates best with the body surface area, followed by the body height and body weight. The brain weight is related to the body weight partly because it increases with increasing height. When adjusted to body dimensions, the brain weight is greater for white men than for black men and for white women than for black men. Our study also shows that the loss of brain mass proceeds at a slightly faster rate than loss of body mass.

Adult↗
PubMed1989

The extremal quotient in small-area variation analysis.

This article reviews the current small-area variation analysis (SAVA) approach to population-based rates of surgery, and describes a new method for ascertaining variance based on the beta-binomial probability distribution of small-area rates. The critical review of the current SAVA approach focuses (1) on how incidence rates are calculated, and (2) on how the significance of the observed magnitude between the largest and smallest rates (i.e., the external quotient) is ascertained. While reducing the problems of calculating rates by considering only certain operative procedures, the new method addresses the current inadequacies of ascertaining significant differences among small areas. Not only does it correctly assess likelihood of an extermal quotient, it also can determine the particular area's rate, producing an unlikely extermal quotient. The method evaluates the probability that the observed magnitude of the extremal quotient is due solely to chance and study design effects, and tables of these probabilities are available for the method's application. A mathematical model, based on a combination of the binomial and beta distributions, uses (1) the sample size, (2) the average of the areas' rates, (3) the variance among the rates, and (4) a specific quotient level to determine the probability of observing the quotient by chance. After computerizing this calculation, probability tables for reasonable values of these four parameters are generated. In addition to looking at just one quotient for each sample, the probability tables facilitate the easy examination of intermediate quotients when the extremal quotient is unlikely due to chance. By alternatively ignoring the highest and lowest rates, two new quotients can be produced and tested. Given that one of these two quotients is likely due to chance, the excluded rate (i.e., producing the unlikely extremal quotient) can be classified as an outliner, and the associated small area should be the focus of more detailed investigation. The probability tables reveal that the external quotient is not the appropriate statistic to be applied in studies where many small areas are to be included. The probability of seeing even a "large" extremal quotient simply by chance rapidly approaches one as the sample size increases. However, an extremal quotient modeled from a beta-binomial distribution can be useful for studies with small sample sizes (e.g., six counties). The use of this beta-binomial model for small-area rates provides a new method of designing and evaluating small-area studies where costs or domain limit the number of areas under consideration.(ABSTRACT TRUNCATED AT 400 WORDS)

Analysis of Variance↗
PubMed1996

Practical issues in conducting small-area variation analysis.

BACKGROUND AND OBJECTIVES: This paper provides a detailed examination of the conduct of a small-area variation analysis (SAVA) health services research project to aid other researchers in performing and interpreting such projects. STUDY CONDUCT: SAVA was performed on hospital admissions with suspected acute cardiac ischemia in the state of Michigan, and the details of each of the steps are presented. The study team consisted of the principal investigator, a biostatistician, a health economist, a medical geographer, and a systems analyst. Data were obtained from the state hospital association and from a commercial demographics source. Small areas for analysis were defined by a patient origin clustering method. Crude area rates were adjusted for age and gender composition of small areas. Multivariate Poisson regression that included sociodemographic variables was performed on adjusted rates. Issues in interpretation of SAVA and practical barriers to primary care SAVA are discussed.

Data Collection↗
PubMed1998

A partial area difference analysis for estimating elimination rate constants and distribution volumes of metabolites.

The true elimination rate constant of a metabolite is calculated using a partial area difference analysis. A linear pharmacokinetic model which describes clearances of parent and metabolite is developed. The model makes no restrictions on the route of administration of the parent but requires time-invariant kinetics for both parent and metabolite. Carbamazepine (CBZ), an antiepileptic, is metabolized to the 10,11-epoxide (CBZE), which is further hydrated to the trans-dihydrodiol (CBZD). Plasma data of the metabolites after a 200-mg single oral dose of Tegretol chewable tablets is used to demonstrate the applicability of the method. Elimination rate constants calculated using partial area analysis are 0.087 +/- 0.015 (h-1) and 0.056 +/- 0.014 (h-1) for CBZE and CBZD, respectively. These correspond to an average half-life of 8.0 h for CBZE and 12.4 h for CBZD, which suggest elimination-rate-limited disappearance of CBZD. The elimination rate constants for CBZE and CBZD calculated using partial areas are comparable to those in the literature determined after oral administration of CBZE. Volumes of distribution of CBZE and CBZD are also estimated to be 0.57 +/- 0.11 L/kg and 0.76 +/- 0.24 L/kg, respectively. The higher values observed with CBZD volumes of distribution are attributed to the higher plasma free fraction of the diol relative to CBZE.

Adult↗
PubMed1993

Small area variation analysis. Methods for comparing several diagnosis-related groups.

In small-area variation analysis, the variation of health care utilization rates, e.g., admission rates, among small areas is calculated. Frequently, the variation of one diagnosis, diagnosis-related group (DRG), or procedure is compared with the variation of another. Unfortunately, the methods generally used to make these comparisons are not consistent. They differ on whether they 1) adjust for the prevalence of the DRGs, 2) distinguish between variation among areas and variation within areas, 3) weight all areas equally, and 4) adjust for multiple admissions per person. None has an associated confidence interval. These discrepancies occur in part because there is no statistical model of small area variation. Without such a model, it is not known how to measure variation, and thus, it is not known how to compare different DRGs. Here, the authors use data on 473 DRGs from 28 counties in Washington state to study the nature of variability. The variation was higher for the more prevalent DRGs, suggesting that adjusting for prevalence may be reasonable. The true coefficient of variation appears to be a "natural" measure of variation, but the usual small area variation statistics do not provide good estimates of the true coefficient of variation. A new estimate is proposed that can be used to compare and test the variability of several DRGs.

Analysis of Variance↗
PubMed1996

Area-metric analysis of dye leakage for evaluation of sealing ability of root canal obturation techniques.

Root canal sealing ability of obturation techniques has been assessed in vitro with various methods. The majority of the methods employ microleakage tracers and particularly dyes. In vitro measurements of dye penetration are either linear or volumetric. Area-metric analysis is a three dimensional registration method of dye leakage. The purpose of the present study was to evaluate in cleared teeth area-metric analysis as opposed to linear analysis of dye penetration. Forty freshly extracted single rooted human teeth were used. Instrumentation was carried out using Hedstroem files with a step back technique. The root canals were obturated using Roth sealer and qutta-percha cones and lateral condensation technique. The roots were then subjected to dye leakage tests under vacuum of 50 mmHg for 20 min. India ink was used as the tracer. The roots were randomly divided in two groups. In Group A the roots were cleared and linear measurements of the dye penetration were recorded The roots in Group B were ground stepwise transversally and subjected to area metric analysis. The results showed that area-metric analysis enabled sufficient recordings of the dye leakage patterns and the volume of the dye penetration could also be calculated.

Coloring Agents↗
PubMedDate not supplied

Bayesian small area cluster analysis of neural tube defects in Newfoundland.

BACKGROUND: The incidence of neural tube defects (NTDs) is declining worldwide due to the implementation of folic acid supplementation programs. Such a program was implemented over 1996-97 in Newfoundland and Labrador, Canada. The geographical distribution of birth incidence was studied prior to and after the implementation of the program to identify regions of residual high incidence. Excess residual cases may potentially be due to genetic causes or incomplete supplementation program implementation. METHODS: Maternal place of residence for all provincial live birth and stillbirth notifications, provincial maternal-fetal medicine referrals, provincial rehabilitation referrals, and all provincial hospitals with NTDs or terminations for NTDs was obtained from 1975 to 2002 for near complete case ascertainment. Bayesian small area analysis was separately performed on cases from 1975-1996 and 1997-2002. The two time periods were compared. RESULTS: Birth incidence of NTDs was noted to decline after 1996, from 5.54/1000 live births to 1.08/1000 live births. 592 cases were found from 1975-1996 and 34 cases from 1997-2002. Relative risk of birth incidence was 0.93-1.18 (95% CI) for 1975-1996 and 0.97-1.02 for 1997-2002 after Bayesian smoothing. One region had an excess of residual cases greater than 34%. CONCLUSIONS: The implications of this observation to the management of the public health initiative imply that overall response to the decrease in cases tends to be uniform across the province, with potentially one area of interest where extra efforts may be devoted.

Bayes Theorem↗
PubMed1992

Evaluation of right ventricular function by regional wall motion analysis in patients after correction of tetralogy of Fallot. Comparison of transventricular and nontransventricular repairs.

Right ventricular function was assessed by regional wall motion analysis and by global function in 62 patients after repair for tetralogy of Fallot. Its relation to surgical procedures, with special attention to right ventriculotomy, was investigated. Patients were classified as follows: group Ia (n = 17), transpulmonary-transatrial repair without right ventriculotomy; group Ib (n = 22), transpulmonary-transatrial repair with minimal right ventriculotomy and small transannular patch; and group II (n = 23), transventricular repair with or without transannular patch. For regional wall motion analysis, fractional area change was used for three anterior parts obtained from hemiaxis area analysis of the lateral right ventriculogram. Ejection fractions were used for global right ventricular function. Functional assessment was done both at rest and during isoproterenol infusion, which is a stress test to evaluate cardiac functional reserve. At rest, group Ia showed better right ventricular anterior wall motion as well as global ejection fraction than did group II. Group Ib showed a global ejection fraction comparable to group Ia, with better regional wall motion in the middle anterior part of the right ventricle despite the depressed upper and lower anterior parts of the right ventricle. Group II showed depressed wall motion of the middle anterior part and the resultant impaired global ejection fraction. During isoproterenol infusion, group Ia showed significant increase in fractional area change of all anterior parts and in global ejection fraction. Group Ib showed significant increases in fractional area change at the middle and lower parts and in global ejection fraction comparable with group Ia. Otherwise, group II showed no significant change in fractional area change, or in global ejection fraction, at the upper and middle parts. These results indicated that transpulmonary-transatrial repair for tetralogy of Fallot provided better postoperative global right ventricular function and its reserve, with less impaired regional wall motion, than did the transventricular repair.

Cardiac Catheterization↗
PubMed1999

Pharmacokinetic and adrenal interactions of IL-10 and prednisone in healthy volunteers.

The pharmacokinetic and adrenal interactions of recombinant human interleukin-10 and prednisolone were examined in this open-label, randomized, four-way crossover study in 12 healthy adult male volunteers. Single doses of IL-10 (8 micrograms/kg s.c.), IL-10 with prednisone (15 mg p.o.), placebo with prednisone, or placebo were administered on four separate occasions with at least 3-week interceding washout periods. Measurements included plasma prednisone, prednisolone and cortisol, unbound prednisolone, and serum IL-10 concentrations. Pharmacokinetic parameters were determined using noncompartmental and model-fitting analysis, while area analysis and an indirect response model were used to assess cortisol dynamics. IL-10 exhibited prolonged serum concentrations owing to dual-absorption processes that were largely unaffected by prednisone. The Cmax values were about 3 ng/mL, while the tmax occurred at 7 to 9 hours. Prednisolone exhibited rapid systemic kinetics with a Cmax of 235 ng/mL, tmax at 1.11 hours, and t1/2 of 2.54 hours with no significant alterations owing to IL-10. Both prednisolone and prednisolone/IL-10 caused marked suppression of cortisol concentrations with similar magnitude and IC50 values; however, IL-10 alone significantly increased the 24-hour AUC of cortisol by 20%. Thus, IL-10 and prednisolone do not interact in disposition or adrenal suppression to a clinically significant degree.

Adrenal Glands↗
PubMed1985

Experimental diabetic neuropathy: impairment of slow transport with changes in axon cross-sectional area.

Analysis of slow axonal transport in the sciatic and primary visual systems of rats with streptozotocin-induced diabetes of 4-6 weeks duration showed impairment of the transport of neurofilament subunits, tubulin, actin, and a 30- and a 60-kDa polypeptide in both systems. The degree of impairment was not uniform. Transport of polypeptide constituents of the slow component b, such as the 30- and 60-kDa polypeptides, appeared to be more severely affected than the transport of constituents of the slow component a, such as neurofilaments. Morphometric analysis of sciatic axons revealed a proximal increase and a distal decrease of axonal cross-sectional area. It is proposed that impairment of axoplasmic transport and changes of axonal size are related. Transport impairment results in a larger number of neurofilaments, microtubules, and other polypeptides in the proximal region of the axon, which increases in size, whereas fewer neurofilaments, microtubules, and other polypeptides reach the distal axons that show a size decrease. Such changes in axonal transport and area are likely to occur in other diabetic animal models and in human diabetes.

Actins↗
PubMed1982

Lung cancer excess in an abandoned lead-zinc mining and smelting area.

Analysis of cancer mortality in whites has revealed a significant excess in both males and females in an old lead/zinc mining and smelting area. This area consists of three rural contiguous counties: Cherokee County, Kansas, Jasper County, Missouri, and Ottawa County, Oklahoma. The lung cancer excess has persisted for at least 28 years for males and 5 years for females. A pilot case/control study is underway in Cherokee County to assess the influence of cigarette smoking, occupation, and residence on the lung cancer excess. Analysis will incorporate the histologic findings. From an environmental perspective, there are numerous mine tailings containing lead, zinc, cadmium, sulfur, germanium, and other chemicals. Considerable dust is airborne. Numerous openings (sink holes and bore holes) connect the old mines with the surface. Radium 226 has been detected in the untreated groundwater.

Carcinogens, Environmental↗
PubMed2001

Assessment of cardiovascular dynamics by pressure-area relations in pediatric patients with congenital heart disease.

OBJECTIVES: It is particularly useful to separately quantify the ventricular contractility and loading conditions for a better understanding of the cardiovascular dynamics in congenital heart disease, where abnormalities in chamber and loading properties may coexist. Furthermore, ventricular contractility and loading conditions may alter independently or simultaneously with disease progression and therapeutic intervention. The objectives of the present study were (1) to test whether ventricular pressure-area analysis can provide such quantitation among patients with various forms of congenital heart disease, (2) to reveal basal cardiovascular interaction in congenital heart disease by means of pressure-area analysis, and (3) to test the feasibility of this method in a simplified and less invasive form to further enhance its clinical value. METHODS: We constructed pressure-area loops during caval occlusion by using transthoracic echocardiographic automated border detection combined with ventricular pressure recordings in 59 pediatric patients with congenital heart disease and in 7 normal control subjects. RESULTS: Area measurements obtained by automated border detection were highly reproducible, and area changes reflected volume changes. The pressure-area data provided load-independent measures of contractility, which were consistently increased by use of dobutamine (P <.05). End-systolic and arterial elastance individually quantified simultaneous changes in ventricular contractility and loading with milrinone infusion and predicted net cardiac performance. The pressure-area analysis better characterized the ventricular contractile states under a variety of loading conditions in congenital heart disease, whereas predominant load dependence of conventional indices confounded them. Furthermore, pressure-area relations were reasonably estimated from a single beat and from aortic pressure data during abdominal compression. CONCLUSIONS: Pressure-area analysis should provide a useful modality with which to assess cardiovascular dynamics in pediatric patients with congenital heart disease in more detail and should thus help improve the management of patients with this disease.

Adolescent↗
PubMed2006

A distinct anatomical network of cortical areas for analysis of motion in far peripheral vision.

We defined cortical areas involved in the analysis of motion in the far peripheral visual field, a poorly understood aspect of visual processing in primates. This was accomplished by small tracer injections within and around the representations of the monocular field of vision ('temporal crescents') in the middle temporal area (MT) of marmoset monkeys. Quantitative analyses demonstrate that the representation of the far periphery receives specific connections from the retrosplenial cortex (areas 23v and prostriata), as well as comparatively stronger inputs from the primary visual area (V1) and from areas surrounding MT (in particular, the medial superior temporal area, MST). In contrast, the far peripheral representation receives little or no input from most other extrastriate areas, including the second visual area (V2), the densely myelinated areas of the dorsomedial cortex, and ventral stream areas; these areas are shown to have robust projections to other parts of MT. Our results demonstrate that the responses of cells in different parts of a same visual area can be determined by different combinations of synaptic inputs, in terms of areas of origin. They also suggest that the interconnections responsible for motion processing in the far periphery of the visual field convey information that is crucial for rapid-response aspects of visual function such as orienting, postural and defensive reactions.

Afferent Pathways↗
PubMed1991

Further issues in small area variations analysis.

In this article, I examine Wennberg's "practice style" hypothesis and the literature on variations among small areas. According to Wennberg, geographic variations in rates of per capita use for many clinical procedures arise mainly from differences over what constitutes appropriate care. I show, however, that the role of practice style in explaining variations among areas has not been clearly demonstrated. I also argue that the practice style hypothesis can neither be established nor refuted by the methods traditionally used to study small areas and, moreover, that inferences about practice style variations cannot be drawn from differences among areas in their rates of use. I thus conclude that more research at the micro level in the practice patterns of the individual physician is needed before major health care initiatives based on small area methodology are undertaken.

Health Policy↗
PubMed1990

Trends in perinatal mortality attributed to congenital malformations in England and Wales during 1974-81: a study of the variations among regional health authority areas.

Analysis of perinatal mortality attributed to congenital malformations in England and Wales, using data from birth and death registration over the years 1974-81 showed significant declines in England and Wales as a whole and in the individual Regional Health Authority (RHA) areas. A greater decrease in death rate from congenital malformations, particularly central nervous system malformations, was seen among stillbirths than among early neonatal deaths. There were marked regional differences in perinatal mortality due to central nervous system malformations over the period but not in cardiovascular system malformations or in other malformations. The highest mortality rates due to central nervous system malformations occurred in the North, North-West, West and South-West of England and in Wales, and the lowest rates in the South and South-East. The larger percentage reductions in the mortality rates were found in most of the regions which had had the highest rates. Possible explanations for the decline in regional rates are suggested.

Cause of Death↗
PubMed1984

Study of the feline and canine populations in the greater Las Vegas area.

Analysis of household dogs and cats, based on age-distribution data and on age-specific birth and survival rates, as well as on pet source, indicated that the dog and cat populations are stable and not increasing in size (lambda congruent to 1). Roaming dogs and cats euthanatized at the pound represented about 5.7% and 8.1% of the estimated dog and cat populations, respectively. The death at the pound seems to be effective in checking pet population growth. Among pets acquired, 84% were less than 1 year of age for dogs as compared with 88% for cats. Breeders and pet shops supplied about 7% of cats and 17% of dogs. About 10% of cats and 10% of dogs were acquired at the pound, while 6.4% of dogs and 14% of cats were acquired as stray. About 45% of dogs and 41% of cats were acquired from pet owners. Some dogs (12.46%) and cats (12%) were imported from outside the Las Vegas area. Of dogs and cats below 2 months of age, 33% and 19.5%, respectively, came from breeders or pet shops or were imported from outside the area. Seventeen percent of unspayed female dogs and 16% of unspayed female cats reproduced. The percentages of spayed females were 77 for dogs and 86 for cats. Forty-five percent of the dogs and 48% of the cats were males. Among dogs at the shelter, 2% were neutered and 26% spayed. At the pound, 24% of dogs were small breeds, 24% medium size breeds, and 52% large breeds.(ABSTRACT TRUNCATED AT 250 WORDS)

Age Factors↗
PubMed2004

Spindle regulation: Mps1 flies into new areas.

Analysis of a mutation in the Drosophila Mps1 ortholog further demonstrates the universality of Mps1 function in the spindle checkpoint, but suggests Mps1 function in centrosome duplication might not be so conserved. The work also contributes new additions to a list of Mps1 functions that continues to grow with each new study.

Animals↗