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PubMed1986

Regional platelet concentration in blood flow through capillary tubes.

Platelet concentration was measured in samples from the various components of a bloodflow circuit, including the reservoir, the tube (with i.d. between 50 and 210 micron), and the discharge. The tube sample was collected by halting the flow and then flushing out a length of tube; thus, this sample collected equally from all radial locations. As the discharge sample was well mixed, it reflected the velocity field in the tube. Each reservoir sample was a traditional bulk collection. To ensure that the results represented the physical effects of flow on regional platelet concentration and could be interpreted with simple mass balance relationships, strong anticoagulation (sodium citrate and heparin) and platelet inhibition (prostaglandin E1) were used. Results for all tube diameters and for reservoir hematocrits from 5.5 to 77% and wall shear rates from 80 to 8000 sec-1 show that tubular platelet concentration is greater than reservoir or discharge platelet concentrations, which are equal. For platelet-rich plasma the tubular platelet concentration is decreased compared to the reservoir or discharge values. Mass balances show that the elevated tubular platelet concentration is due to an excess of platelets in radial locations with below average speeds; coupled with the need for red cells, this suggests that excess platelets have a near-wall location. Nonparametric statistical tests show that wall shear rate is a significant variable at a 0.05 confidence level; inner diameter is not found to be a significant variable, probably because of the limited diameter range studied and the experimental errors involved in determining platelet concentrations.

Blood Flow Velocity↗
PubMed1996

Outcomes of severely abnormal umbilical artery doppler velocimetry in structurally normal singleton fetuses.

OBJECTIVE: To construct a management guide for preterm pregnancies complicated by severely abnormal umbilical artery Doppler velocimetry. METHODS: A retrospective chart review was conducted on all cases of absent or reversed end-diastolic flow umbilical artery Doppler velocimetry identified through an ultrasound data base. Maternal and perinatal outcome variables were retrospectively reviewed and analyzed using both parametric and nonparametric statistical techniques. Seventy-one cases were identified over a 5-year period. After excluding multiple gestations, anomalous fetuses, and two cases that were terminated before 24 weeks' gestation, 56 singleton gestations remained for analysis. RESULTS: Among the 56 subjects, there were 45 survivors and 11 deaths (five fetal and six neonatal deaths). Nonsurvivors had a significantly lower gestational age at diagnosis and delivery. Nonsurviving live-born neonates had lower Apgar scores and were significantly smaller; however, there were no differences in proportion or severity of fetal growth restriction in survivors and nonsurvivors. There were no differences in last biophysical profile before delivery or interval from diagnosis of reversed end-diastolic flow to delivery. Predictors of nonsurvival were the presence of reversed end-diastolic flow and oligohydramnios. Perinatal mortality for reversed end-diastolic flow was 333/1000 and 94/1000 for absent end-diastolic flow. Risk for perinatal death was highly gestational age dependent. For delivery at less than 26 weeks, survival was one of four; at 26-27.9 weeks, survival was seven of 12; and at 28 weeks or greater, survival was 37 of 40. CONCLUSION: Whereas severely abnormal umbilical artery blood flow poses significant risk for pregnancy, perinatal mortality is dominated by gestational age at diagnosis and delivery. This may reflect the severity of the disease or the low survival of very immature gestations. Interventions on behalf of the fetus at very early gestational ages should be undertaken with caution.

Female↗
PubMed1989

Results of the flow cytometry ACTG quality control program: analysis and findings.

The AIDS Clinical Trial Group's (ACTG) Immunology Committee was charged with initiating a quality control program for all laboratories participating in the ACTG program reporting flow cytometry data. Forty-one laboratories were evaluated. This report defines the goals of this program and the subsequent findings after 19 send-outs were made. Both HIV positive volunteer donors and normal age-matched donors were used. Sample sets included both heparin and EDTA anticoagulated bloods. Laboratories were asked to report hematologic parameters as well as flow cytometry data both in percentages and absolute numbers. Results were evaluated using nonparametric statistical analysis. Robust CVs and interquartile ranges were used to define the performance of individual laboratories for each CD subset analyzed. Intralaboratory reproducibility was analyzed by paired sample sets. All laboratories were found to be able to define normal samples as normal. Seventy-five percent of the laboratories were able to define abnormal samples as abnormal. Twenty-five percent could not identify two abnormal samples as abnormal. Forty percent of the labs were found unable to reproduce paired samples within an absolute of +/- 5%. EDTA was found slightly superior to heparin in bloods evaluated by flow cytometry within 30 hr of collection. The analysis of specific histograms, questionnaires, and data analysis led to a specific set of recommendations for performance of flow cytometry studies.

Acquired Immunodeficiency Syndrome↗
PubMed1994

Common measures of asthma severity lack association for describing its clinical course.

BACKGROUND AND OBJECTIVE: To address the problems of increasing asthma morbidity and mortality rates, reliable severity measures must be identified. Accordingly, we compared three measures and their relationship to beclomethasone compliance. METHODS: Three clinical measures (symptom scores, morning peak expiratory flow rates, and number of as needed albuterol inhalations with Nebulizer Chronologs [Forefront Technologies, Inc., Lakewood, Colo.]) were assessed daily in 13 adults with asthma for 8.9 +/- 2.1 weeks. The relationships among these three variables were analyzed in terms of Pearson correlation coefficients. These were evaluated for each of the three possible pairs of the three clinical measures for each of the 13 patients. The relationship between inhaled beclomethasone compliance and the pairwise correlations was studied with the use of nonparametric statistical procedures. RESULTS: In four of the 13 patients, no pairwise correlations between any of the three severity measures were observed. The peak expiratory flow rate-symptom score relationship was observed in eight patients, whereas peak expiratory flow rate-albuterol use and albuterol use-symptom score correlations were each seen in four patients. Mean beclomethasone compliance was 64% and was greatest in those patients whose albuterol use increased concurrently with symptom scores (94% vs 50%, p = 0.02). CONCLUSIONS: The commonly used measures of asthma severity, symptom scores, peak flow rate, and beta-agonist use may not be interchangeable in describing the clinical course. Patients whose beta-agonist use is driven by symptoms tend to be more compliant with use of inhaled corticosteroids.

Administration, Inhalation↗
PubMed1980

Nonparametric analysis of response curves.

Many experimental designs in the behavioral sciences and neurosciences yield for each subject a response curve defined by number of correlated measurements. The common parametric and nonparametric statistical tests assume independent measurements and cannot be used in this context. After reviewing contemporary approaches to this problem, procedures for the cases of two independent samples and two matched samples of response curves are proposed. Each curve is approximated by an orthogonal polynomial. In the case of two independent samples the polynomial coefficients are compared by a multivariate median test while in the case of matched samples a multivariate sign test is used. The methods are illustrated by real data sets.

Adult↗
PubMed1981

Cerebrospinal fluid amine metabolites, tryptophan and clinical parameters in depression. Part 2. Psychopathological symptoms.

The group of 33 severely depressed female patients was divided into 3 equally large subgroups, separately according to their CSF 5-HIAA, HVA, tryptophan and total plasma tryptophan, and the severity of 17 operationally defined psychopathological symptoms was compared between the subgroups containing the highest and lowest biochemical values. Nonparametric statistical testing yielded significant results on several symptoms, when the subgroups were formed from CSF 5-HIAA and HVA. There was only one significant symptom difference between subgroups separated by CSF tryptophan and a few other differences by plasma tryptophan level. The results indicate that lumbar CSF metabolites correlate more with certain individual symptoms than with the global severity of depression.

Anxiety↗
PubMed1982

Comparison of cerebellar Purkinje cell simple spike discharges in adult rats after undernutrition during the suckling period and nutritionally normal rats.

The spontaneous activity of cerebellar Purkinje cells was compared in 100- to 130-day-old rats undernourished during the suckling period (i.e. 0-21 days) and subsequently nutritionally rehabilitated (PU rats), with that in rats of the same strain and of similar age fed normally (age controls), and in normally fed rats of the same strain but approximately one month younger (weight controls). Simple spike activity of single cells was recorded with extracellular microelectrodes in pentothal-anaesthetized animals. The discharge patterns were assessed by on-line computer analysis of the interspike interval distributions with subsequent transformation of the data to enable the results to be evaluated by an analysis of variance. In addition, the distribution of the mean interval, the percentage of intervals less than 30 ms, the percentage of intervals greater than or equal to 150 ms, and the time spent in intervals greater than 150 ms, were compared for the PU rats and pooled controls by a nonparametric statistical test on the untransformed data. None of the results indicated that there were any significant differences between the simple spike activity of Purkinje cells from age- and weight- control rats nor between that in PU rats and the control groups. These results are discussed in relation to the previously reported deficits of granule cells in the cerebella of PU rats.

Action Potentials↗
PubMed1993

Design and analysis of veterinary vaccine efficacy trials.

Vaccination-challenge tests that involve all-or-none responses and do not require a direct comparison between vaccinates and controls can be completely characterized by the binomial distribution. Consumer and producer risks associated with binomial distribution based tests can be adjusted by altering the number of animals involved and the criterion for acceptance. Clinical signs or other outcomes measured on an ordinal or ranking scale should generally be analyzed by nonparametric statistical procedures. Parametric statistical tests are the most appropriate for data measured on an interval scale if the necessary assumptions are met concerning the population sampled. The use of in vitro potency tests in quality control procedures for inactivated vaccines depends on the demonstration of a significant dose-response efficacy relationship in the host animal.

Analysis of Variance↗
PubMed1991

Electrical stimulation of the auditory nerve in deaf kittens: effects on cochlear nucleus morphology.

The present study examines the effects of long-term electrical stimulation of the auditory nerve on the morphology of neurons in the cochlear nucleus in young, sensorineural deaf animals. Kittens, systemically deafened using kanamycin and ethacrynic acid, received bilateral cochlear implants and were stimulated unilaterally for periods of up to four months. After sacrifice, cross-sectional areas of neuron somata were measured with an image-analysis system and compared using nonparametric statistics. The areas of cell somata within the anteroventral cochlear nucleus (AVCN) on the stimulated side were significantly larger than those of corresponding somata on the control, unstimulated side (P less than 0.001). However, there was no statistically significant difference among dorsal cochlear nucleus (DCN) neurons. These results indicate that long-term electrical stimulation of the auditory nerve can at least partially negate some effects of early postnatal auditory deprivation at the level of the cochlear nucleus.

Animals↗
PubMed1993

The efficacy and acceptability of using a jet injector in performing digital blocks.

This prospective, nonblinded study, comparing jet injection with needle-syringe injection of lidocaine in performing digital blocks, tested the hypothesis that jet injection can be used effectively as a less painful way to perform digital blocks. Twenty-four adult patients with injuries of the middle or distal phalanges of the fingers received digital blocks using a jet injector on one side of the finger and a needle-syringe on the other side; pain was assessed at 0, 1, 3, 6, 12, and 24 hours using visual analog scales. Differences in pain scores for the two procedures (jet injector vs needle) were tested at each time period using nonparametric statistical procedures for paired or matched data (paired Wilcoxon). At the time of injection (time 0) and at 12 hours, the jet had a significantly lower pain score than the needle. Comparisons made at the other points were statistically nonsignificant at .05. The anesthesia achieved using the jet injector was considered adequate in 23 of 24 patients. We conclude that the jet injector can be used effectively in performing digital blocks and is less painful than standard needle-syringe methods.

Adult↗
PubMedDate not supplied

Effect of crowd size on patient volume at a large, multipurpose, indoor stadium.

A prediction of patient volume expected at "mass gatherings" is desirable in order to provide optimal on-site emergency medical care. While several methods of predicting patient loads have been suggested, a reliable technique has not been established. This study examines the frequency of medical emergencies at the Syracuse University Carrier Dome, a 50,500-seat indoor stadium. Patient volume and level of care at collegiate basketball and football games as well as rock concerts, over a 7-year period were examined and tabulated. This information was analyzed using simple regression and nonparametric statistical methods to determine level of correlation between crowd size and patient volume. These analyses demonstrated no statistically significant increase in patient volume for increasing crowd size for basketball and football events. There was a small but statistically significant increase in patient volume for increasing crowd size for concerts. A comparison of similar crowd size for each of the three events showed that patient frequency is greatest for concerts and smallest for basketball. The study suggests that crowd size alone has only a minor influence on patient volume at any given event. Structuring medical services based solely on expected crowd size and not considering other influences such as event type and duration may give poor results.

Emergency Medical Services↗
PubMed2005

Electrochemical characterization of cast Ti-Hf binary alloys.

This study characterized the electrochemical behavior of Ti-Hf binary alloys in a simulated oral environment. Ti-Hf alloys (10, 20, 25, 30, 35 and 40 mass% Hf) were prepared by arc-melting titanium sponge and hafnium sponge. Specimens of each alloy (n = 4) were prepared using a dental titanium casting system with a MgO-based investment. Specimens were inspected with X-ray radiography to ensure minimal internal porosity. Castings (n = 4) made from pure titanium and commercially pure titanium were used as controls. The ground flat surface (10 mm x 10 mm) on each specimen where approximately 30 microm was removed was used for the characterization. Sixteen-hour open-circuit potential (OCP) measurement, linear polarization and potentiodynamic cathodic polarization were performed sequentially in aerated (air + 10% CO2) MTZ synthetic saliva at 37 degrees C. Potentiodynamic anodic polarization was conducted in the same medium but deaerated (N2 + 10% CO2) 2 h before and during testing. Polarization resistance (R(P)) and Tafel slopes were determined, as were corrosion current density (I(CORR)) and passive current density (I(PASS)). Results were subjected to nonparametric statistical analysis (alpha = 0.05). The OCP stabilized (mean values -229 mV to -470 mV vs. SCE) for all specimens after the 16-h immersion. Similar passivation was observed for all the metals on their anodic polarization diagrams. The Kruskal-Wallis test showed significant differences in OCP among the test groups (p = 0.006). No significant differences were found in R(P), I(CORR) or I(PASS) among all the metals (p>0.3). Results indicate that the electrochemical behavior of the Ti-Hf alloys examined resembles that of pure titanium.

Alloys↗
PubMed2004

Manipulation of the pill-free interval in oral contraceptive pill users: the effect on follicular suppression.

OBJECTIVE: The purpose of this study was to compare follicular suppression that was produced by 3 different oral contraceptive regimens that differ by treatment in the pill-free interval. STUDY DESIGN: In a university setting, 54 women were assigned randomly to receive either 20 microg ethinyl estradiol+100 microg levonorgestrel followed by 7 pill-free days, 20 microg ethinyl estradiol+150 microg desogestrel followed by 2 days of placebo then 10 microg ethinyl estradiol for 5 days, or 28 days of 20 microg ethinyl estradiol plus 150 microg desogestrel. Follicular suppression was evaluated by serial ultrasound scans and by serum and urinary hormone levels during a 2-month study period. Data were analyzed by nonparametric statistical tests. RESULTS: There was a significant difference in follicle count among the 3 groups (P=.005). Women who were treated with a 7-day pill-free interval experienced the least suppression. Estrogen levels were more variable and led to an observation that overweight (body mass index, >25 kg/m(2)) was associated with reduced follicle suppression (relative risk, 1.6; 95% CI, 1.0, 2.7) and higher estrogen levels (relative risk, 5.3; 95% CI, 1.3, 21). CONCLUSION: Contraceptive pill users who were treated with a 7-day pill-free interval demonstrated less follicular suppression than women who were supplemented with either estrogen alone or estrogen plus progestin. Overweight women were less suppressed than women of normal weight.

Adult↗
PubMed2004

Levator ani thickness variations in symptomatic and asymptomatic women using magnetic resonance-based 3-dimensional color mapping.

OBJECTIVE: This study was undertaken to develop and test a 3-dimensional (3D) color thickness mapping technique on levator ani imaged with magnetic resonance imaging (MRI). METHODS: Supine MRI datasets from 30 women were studied: 10 asymptomatic, 10 with urodynamic stress incontinence, and 10 with pelvic organ prolapse. Levators were manually outlined, and thickness mapping applied. Three-dimensional models were colored topographically, reflecting levator thickness. Thickness and occurrences of absent levator substance (gaps) were compared across the 3 groups, using nonparametric statistical tests. RESULTS: Color thickness mapping was successful in all subjects. There were statistically significant differences in thickness and gap percentages among the 3 groups of women, with thicker, bulkier levators in asymptomatic women, compared with women with prolapse or urodynamic stress incontinence. CONCLUSION: Color thickness mapping is feasible. It may be used to compare levators in symptomatic and asymptomatic women, to study relationships between levator thickness and pelvic floor dysfunction. This technique can be used in larger studies for hypothesis testing.

Adult↗
PubMed2005

Progesterone receptor isoform (A/B) ratio of human fetal membranes increases during term parturition.

OBJECTIVE: The role of progesterone in the control of human parturition remains unsettled. Because there is no systemic progesterone withdrawal before the onset of labor, a 'functional progesterone withdrawal' has been proposed to be operative before human parturition. This may be accomplished by a change in the density of the progesterone receptor (PR) isoforms in myometrium and fetal membranes. The purpose of our study was to determine if spontaneous term labor is associated with changes of PR isoforms (PR-A and PR-B) in the fetal membranes. STUDY DESIGN: Fetal membranes were obtained from women undergoing elective cesarean delivery at term (not in labor group), and from women with a vaginal delivery (labor group). The expression of PR isoforms was assessed by Western blot analysis of amnion and chorio-decidua. Densitometric analysis of PR-A/PR-B ratio was performed. Immunohistochemistry with specific antibodies to PR-A and PR-B was done. Nonparametric statistics were used for analysis. RESULTS: 1) The predominant isoform of PR in women not in labor was PR-B, and PR-A in patients in labor. The ratio of PR-A/PR-B in fetal membranes was significantly higher in women in labor than in those not in labor (for amnion, median 4.3, range [0.9-8.4] vs median 0.4, range [0.3-2.6], P < .001; for chorio-decidua, median 2.0, range [1.1-19.2] vs median 1.2, range [0.1-2.0], P < .05). 2) Fetal membranes expressed both types of PR. 3) Immunohistochemistry showed the presence of PR-A and PR-B in the cytoplasm of amnion epithelial cells, chorion trophoblast, and decidual cells. CONCLUSION: Human parturition at term is associated with changes in PR isoforms in the fetal membranes and, thus, a local 'functional progesterone withdrawal' may operate in human parturition through this mechanism.

Blotting, Western↗
PubMed2005

Expression of bone morphogenetic protein 2 in normal spontaneous labor at term, preterm labor, and preterm premature rupture of membranes.

OBJECTIVE: Genome-wide screening studies of the chorioamniotic membranes unexpectedly identified an increase in the expression of bone morphogenetic protein 2 in spontaneous labor at term. The objective of this study was to determine whether bone morphogenetic protein 2 messenger RNA and protein expression are altered in the chorioamniotic membranes of patients with term labor, preterm labor, and preterm premature rupture of membranes. STUDY DESIGN: Chorioamniotic membranes were obtained from patients at term (with and without labor), with preterm labor (with and without histologic chorioamnionitis), and with preterm premature rupture of membranes (with and without histologic chorioamnionitis). The expression of bone morphogenetic protein 2 was studied by real-time quantitative reverse transcriptase-polymerase chain reaction (n = 88) and immunohistochemistry (n = 124). Nonparametric statistics were used for analysis. Primary amnion cells obtained from women at term not in labor were treated with bone morphogenetic protein 2 to examine whether there was increased prostaglandin E2 expression. RESULTS: The median bone morphogenetic protein 2 messenger RNA and protein expression were significantly higher in the membranes of patients with spontaneous labor at term than in those of patients not in labor at term (P < .001 for both). Bone morphogenetic protein 2 messenger RNA and protein expression were increased in patients with preterm labor with histologic chorioamnionitis than in those without histologic chorioamnionitis (P < .05 and P < .001, respectively). There was no difference in bone morphogenetic protein 2 messenger RNA and protein expression in patients with preterm premature rupture of membranes, regardless of chorioamnionitis (P = .13 and P = .08, respectively). There was a correlation between bone morphogenetic protein 2 and cyclooxygenase 2 protein expression in chorioamniotic membranes (R = .34; P < .001). CONCLUSION: Bone morphogenetic protein 2 messenger RNA and protein expression are increased in the chorioamniotic membranes of patients with spontaneous labor at term and patients with preterm labor associated with histologic chorioamnionitis. Its expression pattern and biologic effects strongly suggest that bone morphogenetic protein 2 is involved in human parturition.

Amnion↗
PubMed2005

Maternal plasma osteoprotegerin concentration in normal pregnancy.

OBJECTIVE: Pregnancy is associated with major changes in calcium metabolism because the neonatal skeleton contains approximately 30 g of calcium, which are largely deposited in the third trimester. Osteoprotegerin (OPG) acts as a decoy receptor for the "Receptor Activator of Nuclear Factor-kappaB Ligand" (RANKL), which is an essential factor for bone remodeling. This study was conducted to determine whether there were changes in maternal plasma OPG concentration during normal pregnancy. STUDY DESIGN: A cross-sectional study was performed in 433 patients of reproductive age (40 nonpregnant and 393 pregnant). Pregnant patients were classified into 4 groups according to gestational age: group 1: 11 to 14 weeks (n = 100); group 2: 15 to 18 weeks (n = 99); group 3: 27 to 30 weeks (n = 100); and group 4: 37 to 42 weeks (n = 94). Plasma OPG concentrations were measured with the use of a sensitive and specific immunoassay. Nonparametric statistics were used for analysis. RESULTS: OPG was detected in the plasma of all women tested. The median OPG concentration was significantly higher in term patients than in those in early pregnancy (median: 6.63 pmol/L [range: 1.57-25.57] vs median: 3.98 pmol/L [range: 0.41-13.71], P < .001). There was no significant difference in plasma OPG concentrations between nonpregnant women and those in groups 1 or 2 (nonpregnant women median: 3.86 pmol/L [range: 1.64-15.29] vs group 1 median: 3.98 pmol/L [range: 0.41-13.71] vs group 2 median: 3.87 pmol/L [range: 1.14-69.83], P = .75). CONCLUSION: The median maternal plasma OPG concentration is higher in the third trimester than in the first trimester of pregnancy. OPG may be involved in the regulation of bone turnover during pregnancy.

Adult↗