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PubMed1994

Deuterium equilibration time in infant's body water.

OBJECTIVE: Equilibration time of deuterium oxide was studied in infants with no restriction of food intake, as in field work stringent conditions have to be relaxed. SUBJECTS: Ten children recovering from marasmatic undernutrition in an Infant Nutrition Centre (CONIN). METHODS: Four males and six females [mean 253 +/- 38 (SD) days old] exclusively bottle-fed were administered a deuterium dose in their first morning feed and followed for a 12 day period. The intercept method was used as the reference to validate the isotope equilibration time within the body water pool calculated with the plateau method. Mean equilibration was found to be 291 +/- 78 (SD) (4.85 +/- 1.3 h). RESULTS: Total body water (TBW) values calculated with both methods differed only by 0.6%, confirming that the deuterium oxide was homogeneously distributed within the body water pool at the plateau equilibration time (4.85 +/- 1.3 h). This period is much larger than the one commonly utilized, 120-180 min (2-3 h). CONCLUSION: Regarding TBW measurements, the intercept method provides the same information as the plateau method. However, the intercept method seems more suitable for field studies when working conditions cannot be controlled. The plateau method can be useful for specific short studies providing a faster assessment of the body water pool in infants.

Age Factors↗
PubMed1993

[Antifertility effects of mifepristone and epostane alone and in combination in rats].

A complete interceptive action on pregnancy was shown after ig mifepristone (RU-486) 16 mg.kg-1 or epostane 96 mg.kg-1 on d 10 of pregnancy in rats. The ig ED50 (95% fiducial limits) of RU-486 when given alone and in combination with epostane 12 mg.kg-1 were found to be 7.8 (5.3-10.0) and 2.6 (2.0-3.3) mg.kg-1, respectively (P < 0.05), while those of epostane when given alone and in combination with RU-486 4 mg.kg-1 were 25.5 (19.4-33.6) and 5.6 (4.7-7.4) mg.kg-1, respectively (P < 0.05). An absorption promotor, sodium dodecyl sulfate 24 mg.kg-1 ig, when given in combination with RU-486 8 mg.kg-1 or epostane 24 mg.kg-1, induced complete interceptive action on pregnancy. Levels of plasma progesterone declined significantly when epostane 12 mg.kg-1 was given in combination with RU-486 4 mg.kg-1 as compared with epostane 12 mg.kg-1 alone (P < 0.05). Results showed that drug combination therapy was of benefit both to RU-486 and epostane in their interceptive actions.

Abortifacient Agents, Steroidal↗
PubMed1994

First-pass ventricular ejection fraction using a single-crystal nuclear camera.

UNLABELLED: The purpose of the study was to evaluate the reliability of ejection fractions obtained from first-pass radionuclide ventriculography with a large field-of-view tomographic single-crystal gamma camera. METHODS: A SPECT camera had its electronics redesigned to improve counting efficiency and was equipped with an experimental ultra-high sensitivity collimator. Left ventricular ejection fraction (LVEF) was measured in 28 patients by 30 degrees RAO first-pass imaging and by "best septal view" LAO planar equilibrium radionuclide ventriculography on a conventional small field of view Anger camera. For 28 other patients, first-pass ejection fractions were compared to multicrystal gamma camera values. Visual analysis was performed to judge clinical acceptability of first-pass images for identification of wall-motion abnormalities. RESULTS: Linear regression analysis of first-pass against equilibrium ejection fraction demonstrated good correlation (r = 0.92; slope = 0.90; intercept = 3.8; s.e.e. = 6.4%). First-pass ejection fraction values also correlated linearly with multicrystal camera values for the left ventricle (r = 0.94; slope = 1.05; intercept = 1.3; s.e.e. = 5.3%). For a subgroup of 19 patients, single-crystal camera right ventricle ejection fraction demonstrated good correlation with multicrystal camera values (r = 0.82; slope = 1.15; intercept = 1.3; s.e.e. = 6.1%). Interobserver variability correlated as r = 0.99 for LVEF ejection fraction and r = 0.92 for RVEF. Chi-square analysis of single-crystal first-pass image visual scores versus those from the gated equilibrium acquisitions showed close agreement (p < 10(-8)). CONCLUSIONS: The evaluated camera/collimator system measured left and right ventricular ejection fraction accurately. Lung frame correction and dual regions were superior to paraventricular background correction and a fixed end-diastolic region.

Feasibility Studies↗
PubMed1996

Comparison of technetium-99m-HMPAO and xenon-133 measurements of regional cerebral blood flow by SPECT.

UNLABELLED: This study compares 99mTc-HMPAO count ratios and derived regional cerebral blood flow (rCBF) to 133Xe rCBF ratios and true rCBF (ml/min/100 g), respectively. METHODS: Technetium-99m-HMPAO distribution was evaluated in 14 patients and 5 normal control subjects. Immediately after 133Xe SPECT, subjects received 22 +/- 4mCi 99mTc-HMPAO, and images were acquired 15 min after injection. rCBF (ml/min/100 g, 133Xe) or regional count density (99mTc-HMPAO) were extracted from 24 ROI located 6 cm above the cantho-meatal line. These data were also normalized to global cerebral blood flow (gCBF) for 133Xe or to global count density (gCD) for 99mTc-HMPAO. Technetium-99m-HMPAO ROI data also were expressed in units of ml/min/100 g by relating gCD to gCBF. Comparisons between 133Xe and 99mTc-HMPAO were evaluated using a Bonferroni-corrected paired t-test and by linear regression analysis. RESULTS: Profile plots demonstrated agreement in the pattern of relative distribution between rCBF ratios (133Xe) and count density ratios (99mTc-HMPAO). Regression analysis indicated a significant correlation (r = 0.78), with a modest slope (0.52) and a large intercept (0.48). A closer correlation (r = 0.92) was found for the comparison between rCBF (133Xe) and derived 99mTc-HMPAO rCBF. The slope was closer to one (0.82) and the intercept closer to zero. This relationship was also examined during high rCBF after a subset of these subjects (n = 7) was injected intravenously with 1 g acetazolamide. Again, profile plots and regression analysis demonstrated agreement in the pattern of distribution (ratios) between 133Xe and 99mTc-HMPAO (r = 0.66). However, the slope was reduced and the intercept increased relative to resting data. Absolute flow correlations showed some improvement relative to the ratio data (r = 0.77). CONCLUSION: The distribution of 99mTc-HMPAO is linearly related to rCBF measured by 133Xe SPECT, although our data suggest that 99mTc-HMPAO mildly underestimates rCBF above 80 ml/min/100 g. These results are similar to our previous comparison of 99mTc-ECD and 133Xe.

Adult↗
PubMed1979

The use of muscle forces by simple orthodontic appliances.

Orthodontic appliances of simple construction have been described. They are valuable in intercepting the deforming action of perioral muscle function or malfunction. The same muscles that have the deforming potential may be enlisted to correct dental malocclusions. Early interception often prevents a problem of considerably greater magnitude at a later date.

Acrylic Resins↗
PubMed2005

The effectiveness of phase I orthodontic treatment in a Medicaid population.

BACKGROUND: The effectiveness of early orthodontic treatment for Medicaid-enrolled children in the mixed dentition was assessed and compared with results in a population of private-pay patients. MATERIAL: Pre- and posttreatment casts from 196 subjects treated with interceptive orthodontics in the mixed dentition were evaluated by using the peer assessment rating (PAR) index and the index of complexity, outcome, and need (ICON). Ninety-six of the patients were treated at Odessa Brown Community Clinic in Seattle; their treatment was paid by Medicaid. One hundred private-pay patients were treated at the University of Washington graduate orthodontic clinic. The Medicaid and private-pay populations were comparable with respect to initial severity of malocclusion, as assessed by both indexes. RESULTS: PAR and ICON scores fell by similar amounts in the Medicaid (44.1% and 37.5%, respectively) and private-pay (46.8% and 37.3%, respectively) populations. Thus, the groups exhibited similar degrees of improvement with interceptive orthodontic treatment. According to the PAR and ICON, midline discrepancy, overjet, and esthetics exhibited the greatest improvement. The Medicaid population missed significantly more appointments and had poorer oral hygiene than the private-pay group, but these factors did not appear to worsen the outcomes, as measured by the 2 indexes. An appliance with 2 bands and 4 brackets was the most commonly used, and it produced the most significant treatment effect. CONCLUSIONS: Phase I orthodontic treatment significantly reduces malocclusion severity in Medicaid and private-pay populations. There was no difference in initial severity or final outcome, as assessed by the PAR and ICON, between Medicaid and private-pay populations. The degree of improvement in PAR scores did not appear to be associated with compliance.

Analysis of Variance↗
PubMed1989

The system of prosthetic treatment for CLAP patients.

The prosthetic treatment of CLAP patients is usually done in three phases: an interceptive treatment during two stages of orthodontics, the definitive prosthetic treatment and usually the secondary treatment. In the interceptive phase we use clasp-retained partials; the definitive treatment is achieved mostly by telescope-retained partials. There is seldom an indication for Maryland-bridges or for dental implants.

Cleft Lip↗
PubMed2002

Appropriateness of orthodontic referrals: self-perceived and normative treatment needs of patients referred for orthodontic consultation.

OBJECTIVES: The aims of this prospective study were to evaluate the self-perceived and normative orthodontic treatment needs of children referred for orthodontic consultation and to determine the proportion of children who were inappropriately referred. METHODS: The sample consisted of 257 children with a mean age of 12.0 years (SD = 2.4). An orthodontist assessed the children's normative treatment need using the dental health component (DHC) of the index of orthodontic treatment need (IOTN), and for patients in the mixed dentition the need for interceptive treatment was assessed. Questionnaires were answered by both the child and the parent to assess satisfaction with dental appearance and desire for treatment. RESULTS: The distribution of the IOTN grades showed that 73% of the children had definite need while 27% had borderline/no need for orthodontic treatment. Twenty-six per cent of children and 17% of parents did not express orthodontic concern, even though more than half of these children were in definite need of treatment as assessed by IOTN. The children's orthodontic concern was significantly related to the DHC scores. Out of the 103 children who were in the mixed dentition, only about 16% required interceptive treatment. CONCLUSIONS: The results indicated that a significant number of children were inappropriately referred for orthodontic treatment. Referring dentists need to assess the normative treatment needs of the children as well as the children's and parents' commitment and desire for orthodontic treatment before deciding on the need for referral.

Child↗
PubMedDate not supplied

Early detection and prevention of mandibular tooth transposition.

Distal migration of the mandibular permanent lateral incisor happens rarely and it can be discovered radiographically in the early mixed dentition. If unattended, the tooth may erupt ectopically, usually distal to its normal anatomical position and occlusal to the developing first premolar, and it can become transposed with the permanent canine. Early detection and immediate interceptive removal of the retained deciduous lateral incisor and canine, followed by uprighting the ectopic lateral incisor to its normal anatomical position in the arch, will intercept the problem and prevent the developing transposition.

Bicuspid↗
PubMed2005

Diagnosis and prevention of maxillary cuspid impaction.

Early diagnoses and prevention of maxillary cuspid impactions can save much time when treating patients orthodontically. Effective recognition and interception requires initial diagnosis at the dental age of about eight years. When a cuspid bulge is absent, diagnosis with oriented lateral and frontal radiographs is advocated and has been shown to aid in the positive recognition of lingually positioned unerupted maxillary cuspids at risk for impaction. Recommended treatment is early removal of maxillary deciduous cuspids and perhaps deciduous first premolars. Lateral and frontal radiographs should be taken at six-month intervals to follow the intra-bony eruptive movement of the permanent cuspids until they have entered the oral cavity. Failure to diagnose and intercept the potentially impacted cuspid often leads to serious malpositions that require extensive mechanical therapy for proper alignment and good function.

Child↗
PubMed1999

Noninvasive glucose monitoring: comprehensive clinical results. Cygnus Research Team.

CONTEXT: Intensive diabetes management using frequent blood glucose measurements to guide therapy has been shown to significantly improve short- and long-term outcomes. Development of a device that makes possible frequent, automatic, painless, and accurate measurements of glucose would facilitate intensive management. OBJECTIVE: To determine the accuracy of the GlucoWatch automatic glucose biographer (Cygnus Inc) compared with that of serial blood glucose measurements. DESIGN: Multicenter comparative study of the GlucoWatch biographer and the HemoCue blood glucose analyzer (Aktiebolaget Leo) performed between August 29 and October 17, 1998. Participants wore up to 2 biographers during the 15-hour study session and performed 2 fingersticks per hour for comparative blood glucose measurements. The biographers were calibrated with a single HemoCue measurement after a 3-hour warm-up period. Diet and insulin were manipulated to produce a broad glycemic range during the study. SETTING: Controlled clinical environment at 2 diabetes centers and 3 contract research organizations in the United States. PARTICIPANTS: A total of 92 subjects (mean [SD] age, 42.1 [15.1] years; 59.8% women) with type 1 or 2 diabetes requiring treatment with insulin. MAIN OUTCOME MEASURES: Mean error, mean absolute error, correlation, slope, and intercept using Deming regression, and clinical significance of differences between biographer readings and blood glucose measurements using the Clarke error grid. RESULTS: Results showed close tracking of blood glucose over a range of 2.2 to 22.2 mmol/L (40-400 mg/dL) for up to 12 hours using a single point calibration. The biographer readings lagged behind serial blood glucose values by a mean of 18 minutes. An analysis of 2167 data pairs shows a linear relationship (r = 0.88; slope = 1.03; intercept = -0.33 mmol/L [-6 mg/dL]) between biographer readings and serial glucose measurements. The mean absolute error between the 2 measurements was 15.6% (mean error [SD], -0.07 [1.82] mmol/L [-1 [33] mg/dL]), and 96.8% of the data fell in the therapeutically relevant regions of the error grid analysis. CONCLUSION: These results demonstrate close agreement between GlucoWatch biographer readings and blood glucose measurements using repeated fingerstick blood samples. The automatic, frequent, and noninvasive measurements obtained with the biographer provides more information about glucose levels than the current standard of care.

Adult↗
PubMed1996

The trypsin-induced leucostasis which leads to emphysema in the hamster is not due to contaminating endotoxins.

Intravenous injection of trypsin in the rat induces early lung leucostasis and emphysema of delayed onset. This report confirms that this emphysema is not rat-specific and that the leucostasis is not related to the presence of contaminating endotoxin in the trypsin. In hamsters (n = 37), leucostasis did not occur when they were injected with heat-treated trypsin, but numerous granulocytes were sequestered in the vessels of hamsters receiving a fresh solution of trypsin. In these hamsters, the number of granulocytes harvested by lavage increased significantly (1.87 x 10(6) per ml, P < 0.001) compared with hamsters injected with either heat-denatured trypsin (0.89) or saline (0.86), or compared with controls (0.86). Emphysema was inconstantly observed in hamsters 6 or 12 weeks after injection with trypsin for 1 h. It was frequently (17/20) present and always (20/20) well developed (intercept + 180 per cent) in the 2-h perfused hamsters whose lungs were abnormally heterogeneous (index + 100 per cent) relative to the seven controls and to the nine saline-injected hamsters. The efficiency of trypsin in triggering emphysema (percentage of hamsters having abnormal values of intercept) was dependent on the time of perfusion. This form of experimental emphysema is thus considered to be due to an endotoxin-independent leucostasis.

Animals↗
PubMedDate not supplied

Measuring cognitive change in a cohort of patients with Alzheimer's disease.

Annualized rates of cognitive change in Alzheimer's disease (AD), an important index of disease progression, show marked variability. To determine factors leading to such variability, we computed rates of change in a cohort of patients with AD tested annually with the Mini Mental State Examination (MMSE) and the more detailed Dementia Rating Scale (DRS). Estimates of rates of change (slopes) and intercepts were calculated using least squares and best linear unbiased predictors (BLUPs). Potential predictors of rates of change were examined using multivariate linear regression analysis. We found that the MMSE had more noise than the DRS. For the MMSE, slopes showed a moderate floor effect and a slight ceiling, depending on initial MMSE scores. These effects were less prominent for the DRS, for which slopes increased as intercepts decreased. In analyses of predictors of change, the MMSE was less useful than the DRS. In multiple linear regression models using DRS data, predictors showed statistically stronger effects and explained a greater extent of variation of slopes than did similar models using MMSE data. For example, among patients who died and underwent brain examination at autopsy, neuropathology of Lewy bodies plus AD (Lewy Body variant; LBV) was associated with significantly faster rates of cognitive decline compared to pure AD in analyses that used the DRS, but only trends were identified with the MMSE. The metric properties and longitudinal characteristics of cognitive tests and the statistical methods used to calculate change are key factors in obtaining reliable estimates of change in studying cohorts of patients with AD.

Aged↗
PubMed1982

Effect of bile acids on 1,2-dimethylhydrazine-induced colon cancer in rats.

The effects of intercepting a part of the enterohepatic circulation of bile acids by ileal resection or bypass on the quantitative and qualitative changes of fecal bile acids were investigated in rats, and the relationship of these changes to the development of DMH-induced colon cancer was studied. The daily fecal total bile acid level was increased in all intercepted groups, especially those with long resection and exclusion. Total bile acid levels played a greater role in the development of DMH-induced colon cancer than did primary or secondary bile acid levels individually. Our findings suggest that bile acid acts as a promoter in the development of colon cancer.

1,2-Dimethylhydrazine↗
PubMed2000

The chirality of the cholesteric phases of DNA and G-wires: its connection to their molecular structures.

While the handedness of the cholesteric phases formed by assembled guanosine derivatives (G-wires) follow the correlation right-handed helices-->right-handed cholesterics (left-handed -->left-handed), the cholesteric phase formed by B-DNA (right-handed helix) is left-handed. This apparent discrepancy is overcome by considering pitch (p) variations with temperature. Plots of p(-1) versus T(-1) have, in fact, the same trend (positive intercept and negative slope) in the case of right-handed G-wires and B-DNA, while for the left-handed G-wire of deoxyguanosine monophosphate (dGMP), the opposite behavior is observed (negative intercept and positive slope). Therefore, the relation between molecular handedness and cholesteric helicity cannot, in general, be assessed by using measurements based on a single temperature; hence the temperature variation of the cholesteric parameters should be investigated. In all cases there is no remarkable salt effect on the cholesteric parameters.

Animals↗
PubMed2004

Effects of data limitations when modeling fatal occupational injury rates.

BACKGROUND: Occupational fatal injury rate studies are often based upon uncertain and variable data. The numerator in rate calculations is often obtained from surveillance systems that can understate the true number of deaths. Worker-years, the denominator in many occupational rate calculations, are frequently estimated from sources that exhibit different amounts of variability. METHODS: Effects of these data limitations on analyses of trends in occupational fatal injuries were studied using computer simulation. Fatality counts were generated assuming an undercount. Employment estimates were produced using two different strategies, reflecting either frequent but variable measurements or infrequent, precise estimates with interpolated estimates for intervening years. Poisson regression models were fit to the generated data. A range of empirically motivated fatality rate and employment parameters were studied. RESULTS: Undercounting fatalities resulted in biased estimation of the intercept in the Poisson regression model. Relative bias in the trend estimate was near zero for most situations, but increased when a change in fatality undercounting over time was present. Biases for both the intercept and trend were larger when small employment populations were present. Denominator options resulted in similar rate and trend estimates, except where the interpolated method did not capture true trends in employment. CONCLUSIONS: Data quality issues such as consistency of conditions throughout the study period and the size of population being studied affect the size of the bias in parameter estimation.

Accidents, Occupational↗
PubMed1982

Relationships among ontogenetic, static, and evolutionary allometry.

The relationship between ontogenetic, static, and evolutionary levels of allometry is investigated. Extrapolation from relative size relationships in adults to relative growth in ontogeny depends on the variability of slopes and intercepts of ontogenetic vectors relative to variability in length of the vector. If variability in slopes and intercepts is low relative to variability in length, ontogenetic and static allometries will be similar. The similarity of ontogenetic and static allometries was tested by comparing the first principal component, or size vector, for correlations among 48 cranial traits in a cross-sectional ontogenetic sample of rhesus macaques from Cayo Santiago with a static sample from which all age- and sex-related variation had been removed. The vector correlation between the components is high but significantly less than one while two of three allometric patterns apparent in the ontogenetic component are not discernable in the static component. This indicates that there are important differences in size and shape relationships among adults and within ontogenies. Extrapolation from intra-or interspecific phenotypic allometry to evolutionary allometry is shown to depend on the similarity of genetic and phenotypic allometry patterns. Similarity of patterns was tested by comparing the first principal components of the phenotypic, genetic, and environmental correlation matrices calculated using standard quantitative genetic methods. The patterns of phenotypic, genetic, and environmental allometry are dissimilar; only the environmental allometries show ontogenetic allometric patterns. This indicates that phenotypic allometry may not be an accurate guide to patterns of evolutionary change in size and shape.

Aging↗
PubMed1993

Human positron emission tomographic [18F]fluorodopa studies correlate with dopamine cell counts and levels.

Postmortem counts of dopaminergic cell densities in the substantia nigra (5 subjects) and striatal levels of dopamine (DA) and its metabolites (6 subjects) were determined on 1 parkinsonian (PD), 3 progressive supranuclear palsy (PSP), 1 amyotrophic lateral sclerosis, and 1 Alzheimer's case who had been positron emission tomography scanned with 6-[18F]fluorodopa during life. [18F]Fluorodopa uptake rate constants, which presumably depend on the number of functioning striatal DA terminals, were strictly proportional to cell densities (significant correlation with zero intercept) and also correlated significantly with striatal DA levels but with an intercept indicating greater losses of DA than of terminals in PSP and PD. Postmortem data on 6 PD, 1 PSP, and 9 neuronally normal controls substantiated the significant correlation between cell counts and DA levels, with the latter being the more depressed in pathological cases.

Adult↗