Applications of Extensions of Bivariate Rank Sum Statistics to the Crossover Design to Compare Two Treatments Through Four Sequence Groups

Summary This article describes applications of extensions of bivariate rank sum statistics to the crossover design with four sequence groups for two treatments. A randomized clinical trial in ophthalmology provides motivating background for the discussion. The bilateral design for this study has four sequence groups T:T, T:P, P:T, and P:P, respectively, for T as test treatment or P as placebo in the corresponding order for the left and right eyes. This article describes how to use the average of the separate Wilcoxon rank sum statistics for the left and right eyes for the overall comparison between T and P with the correlation between the two eyes taken into account. An extension of this criterion with better sensitivity to potential differences between T and P through reduction of the applicable variance has discussion in terms of a conceptual model with constraints for within‐side homogeneity of groups with the same treatment and between‐side homogeneity of the differences between T and P. Goodness of fit for this model can have assessment with test statistics for its corresponding constraints. Simulation studies for the conceptual model confirm better power for the extended test statistic with its full invocation than other criteria without this property. The methods summarized here are illustrated for the motivating clinical trial in ophthalmology, but they are applicable to other situations with the crossover design with four sequence groups for either two locations for two treatments at the same time for a patient or two successive periods for the assigned treatments for a recurrent disorder. This article also notes that the methods based on its conceptual model can have unsatisfactory power for departures from that model where the difference between T and P via the T:T and P:P groups is not similar to that via the T:P and P:T groups, as might occur when T has a systemic effect in a bilateral trial. For this situation, more robust test statistics have identification, but there is recognition that the parallel groups design with only the T:T and P:P groups may be more useful than the bilateral design with four sequence groups.     

Proton magnetic resonance relaxation studies on the structure of mixed micelles of Triton X-100 and dimyristoylphosphatidylcholine.

Proton magnetic resonance and gel chromatographic studies on mixtures of phospholipid and the nonionic surfactant Triton X-200 have shown that at temperatures above the thermotropic phase transition of the phospholipid and below the cloud point of Triton, mixed micelles are present at molar ratios above about 2:1 Triton/phospholipid. Proton T1 and T2 (from line widths) relaxation times are reported for protons in Triton micelles and in mixed micelles of Triton and dimyristoylphosphatidylcholine at a molar ratio of 3:1 Triton/phospholipid. The T1 values and their temperature dependence and the activation energies of the various Triton proton groups appear to reflect internal motions of the Triton molecules in the micelle. Measurements of the T1/T2 ratio and frequency dependence (55-220 MHz) suggest that the hydrophobic tert-butyl group in Triton is observed under extreme narrowing conditions. The T1 and T2 values of Triton are unchanged in the presence of phosphatidylcholine. The T1 values of various protons of dimyristoylphosphatidylcholine in mixed micelles are similar to those reported for the phospholipid in sonicated vesicles, which are used as membrane models, and presumably the same coupled trans-gauche motions dominate. The T2 values for the terminal methyl and choline methyl protons in the phospholipid are longer than those reported for these groups in vesicles. Hence, the motion of the phospholipid in the mixed micelles appears to be less restricted than in vesicles. T1 measurements in H20/D20 mixtures are consistent with the idea that water does not penetrate the hydrophobic core of the mixed micelles, while water does solvate the polar oxyethylene and choline methyl groups. Titration with Mn2+ confirms that the oxyethylene and choline methyl groups are on the exterior of the mixed micelle while the hydrophobic groups are located in the micellar interior.     

The characterization of Chilean and Bolivian Trypanosoma cruzi stocks from Triatoma infestans by isoelectrofocusing

Culture forms of 12 Chilean and 9 Bolivian Trypanosoma cruzi stocks were compared isoenzymatically by the following enzymes: non-specific esterase, phosphoglucomutase, glucose-6-phosphate dehydrogenase, glucosephosphate isomerase, and alcohol dehydrogenase. On the basis of the electrophoretic mobility of these enzymes the stocks were classified into two main groups. Ten Chilean stocks were characterized as group II; two stocks showed enzyme patterns of group I. In contrast, five Bolivian stocks were classified as belonging to group I, the other four to group II. The results show that the two groups of T. cruzi overlap in Triatoma infestans suggesting that both groups of T. cruzi are infective for man. The classification of stocks into two groups is discussed in the light of published results of Brazilian T. cruzi stocks. A strong association of groups with the transmission cycles as it seems to be in Brazil does not exist in Chile and Bolivia.     

Effects of Transient and Continuous Wheel Running Activity on the Upper and Lower Limits of Entrainment to Light‐Dark Cycles in Female Hamsters

The entrainment limits to light‐dark cycles can be modified by the experimental conditions under which they are tested. Among the factors that may influence entrainment is the amount of wheel running exerted by the animal. In the present work, the effects of transitory and continuous wheel running on entrainment to light‐dark cycles were tested using a range of T cycles at the entrainment limits. Four groups of female hamsters were submitted to 1 h stepwise changes in T cycles. Two groups were exposed to T cycles of which the period was shortened at the lower limit from T22 to T18, and the other two groups were exposed to cycles that lengthened at the upper limit from T27 to T32. One of the groups at the lower limit and one at the upper limit had continuous access to a running wheel, while the others had the wheel locked, except at certain T when a lack of period control by T cycle appeared. The study demonstrates that access to running wheel widens the limits of entrainment to LD cycles. Specifically, the following observations were made: the effects of wheel running for entrainment were more evident in the groups with continuous access to wheel, as they did entrain to T19 and T32; continuous access to a wheel produced aftereffects only after T19, but not under T32; and when animals without a wheel showed relative coordination, unlocking the wheel favored entrainment in all the animals at T31, but in only 1 out 6 at T19. All of these indicate a different effect of the wheel running on the upper and lower limits of entrainment.     

Effects of transient and continuous wheel running activity on the upper and lower limits of entrainment to light-dark cycles in female hamsters

The entrainment limits to light-dark cycles can be modified by the experimental conditions under which they are tested. Among the factors that may influence entrainment is the amount of wheel running exerted by the animal. In the present work, the effects of transitory and continuous wheel running on entrainment to light-dark cycles were tested using a range of T cycles at the entrainment limits. Four groups of female hamsters were submitted to 1 h stepwise changes in T cycles. Two groups were exposed to T cycles of which the period was shortened at the lower limit from T22 to T18, and the other two groups were exposed to cycles that lengthened at the upper limit from T27 to T32. One of the groups at the lower limit and one at the upper limit had continuous access to a running wheel, while the others had the wheel locked, except at certain T when a lack of period control by T cycle appeared. The study demonstrates that access to running wheel widens the limits of entrainment to LD cycles. Specifically, the following observations were made: the effects of wheel running for entrainment were more evident in the groups with continuous access to wheel, as they did entrain to T19 and T32; continuous access to a wheel produced aftereffects only after T19, but not under T32; and when animals without a wheel showed relative coordination, unlocking the wheel favored entrainment in all the animals at T31, but in only 1 out 6 at T19. All of these indicate a different effect of the wheel running on the upper and lower limits of entrainment.     

First record in South America of Didymosulcus palati and Didymosulcus philobranchiarca (Digenea, Didymozoidae) with new hosts records and pathological alterations

Two species of Didymozoidae, Didymosulcus palati (Yamaguti 1970) and Didymosulcus philobranchiarca (Yamaguti 1970) were reported for the first time in South America, Atlantic Ocean, parasitizing three different tuna species from the coast of Rio de Janeiro, Brazil: Thunnus atlanticus (Lesson), Thunnus albacares (Bonnaterre) and Thunnus obesus (Lowe). Pairs of D. philobranchiarca were found on gill arches of T. albacares and T. obesus, in longitudinal rows of yellow cysts located inside grooves in the hard denticle palate (new site) of the three hosts species studied, and as disperse groups of cysts in the operculum (new site) and gill arches of T. atlanticus (new host record). D. palati occurred as disperse groups of encysted worm pairs in the gill arches of T. albacares and T. obesus and in gill arches and operculum of T. atlanticus (new host record). The pathological alterations induced by D. philobranchiarca in the palate of T. atlanticus are described for the first time. Original measurements and figures are presented.     

Genomic analyses, gene expression and antigenic profile of the trans-sialidase superfamily of Trypanosoma cruzi reveal an undetected level of complexity

The protozoan parasite Trypanosoma cruzi is the etiologic agent of Chagas disease, a highly debilitating human pathology that affects millions of people in the Americas. The sequencing of this parasite's genome reveals that trans-sialidase/trans-sialidase-like (TcS), a polymorphic protein family known to be involved in several aspects of T. cruzi biology, is the largest T. cruzi gene family, encoding more than 1,400 genes. Despite the fact that four TcS groups are well characterized and only one of the groups contains active trans-sialidases, all members of the family are annotated in the T. cruzi genome database as trans-sialidase. After performing sequence clustering analysis with all TcS complete genes, we identified four additional groups, demonstrating that the TcS family is even more heterogeneous than previously thought. Interestingly, members of distinct TcS groups show distinctive patterns of chromosome localization. Members of the TcSgroupII, which harbor proteins involved in host cell attachment/invasion, are preferentially located in subtelomeric regions, whereas members of the largest and new TcSgroupV have internal chromosomal locations. Real-time RT-PCR confirms the expression of genes derived from new groups and shows that the pattern of expression is not similar within and between groups. We also performed B-cell epitope prediction on the family and constructed a TcS specific peptide array, which was screened with sera from T. cruzi-infected mice. We demonstrated that all seven groups represented in the array are antigenic. A highly reactive peptide occurs in sixty TcS proteins including members of two new groups and may contribute to the known cross-reactivity of T. cruzi epitopes during infection. Taken together, our results contribute to a better understanding of the real complexity of the TcS family and open new avenues for investigating novel roles of this family during T. cruzi infection.     

Postparturitional testosterone surge in male offspring of rats stressed and/or fed ethanol during late pregnancy

Male offspring of rats exposed to restraint stress and/or alcohol during late pregnancy show aberrant patterns of sexual behavior masculinization and defeminization that vary as a function of treatment. The impact of these treatments on the postparturitional testosterone (T) surge that contributes to sexual behavior differentiation was investigated. Plasma T was measured using radioimmunoassay in individual males sampled on day 21 of gestation within 10 min of cesarean delivery or 1, 2, or 4 h thereafter. Neonatal T in the group exposed only to stress did not differ from that in the control group. T was lower than control levels at birth in both alcohol groups. The magnitude of the T surge that occurred during the first hour of birth in the control group was diminished by 50% in both alcohol groups, whose T pattern was very similar. There was no common alteration in postparturitional T associated with the increased lordotic behavior potential that males in all three treatment groups typically share, nor were there idiosyncratic endocrine abnormalities linked to the very different male copulatory pattern each exhibits. Exposure to an abnormal T milieu during fetal as well as neonatal ontogeny may underlie the etiology of the different sexual behavior patterns exhibited by males exposed to stress and/or alcohol. Possible unique effects each treatment exerts on perinatal plasma T and it's aromatization to estradiol in hypothalamic targets are discussed.     

Zwitterionic polysaccharides stimulate T cells by MHC class II-dependent interactions

Polysaccharides of pathogenic extracellular bacteria commonly have negatively charged groups or no charged groups at all. These molecules have been considered classic T cell-independent Ags that do not elicit cell-mediated immune responses in mice. However, bacterial polysaccharides with a zwitterionic charge motif (ZPSs), such as the capsular polysaccharides of many strains of Bacteroides fragilis, Staphylococcus aureus, and Streptococcus pneumoniae type 1 elicit potent CD4(+) T cell responses in vivo and in vitro. The cell-mediated response to ZPS depends on the presence of both positively charged and negatively charged groups on each repeating unit of the polysaccharide. In this study, we define some of the requirements for the presentation of ZPS to CD4(+) T cells. We provide evidence that direct interactions of T cells with APCs are essential for T cell activation by ZPS. Monocytes, dendritic cells, and B cells are all able to serve as APCs for ZPS-mediated T cell activation. APCs lacking MHC class II molecules do not support this activity. Furthermore, mAb to HLA-DR specifically blocks ZPS-mediated T cell activation, while mAbs to other MHC class II and class I molecules do not. Immunoprecipitation of lysates of MHC class II-expressing cells following incubation with ZPS shows binding of ZPS and HLA-DR. Electron microscopy reveals colocalization of ZPS with HLA-DR on the cell surface and in compartments of the endocytic pathway. These results indicate that MHC class II molecules expressing HLA-DR on professional APCs are required for ZPS-induced T cell activation. The implication is that binding of ZPS to HLA-DR may be required for T cell activation.     

Distinct classes of human T-cell activation antigens

The characterization of three groups of antigens expressed by activated human T lymphocytes and detected by monoclonal antibodies is reported. Antigens defined by OKT19, OKT21, and OKT22 do not appear on in vitro activated T cells until increases in DNA synthesis become apparent and are not detected on most Interleukin 2 (IL-2)-independent cell lines and normal peripheral blood lymphocytes, monocytes, and granulocytes. Cell surface molecules reactive with the monoclonal antibodies OKT23 and OKT24 are displayed prior to any notable increase in DNA synthesis and are present on IL-2 independent cell lines, irrespective of lineage. T23 and T24 do not appear on peripheral blood cells and their distribution more closely resembles that of the T9 antigen (the receptor for transferrin) than antigens of the other groups. The third group of antigens, T14 and T20, have been classified as "early" antigens relative to DNA synthesis. They are expressed by distinct populations of normal lymphoid cells as well as by some IL-2-independent cell lines. Display of each group of activation antigens on T lymphocytes can be induced by either phytohemagglutinin, purified protein derivative from tuberculin, or allogeneic non-T cells, is not restricted to the OKT4+ or OKT8+ subsets, and is predominant on cells exhibiting the light-scattering properties of blast cells. The relative lack of expression of these antigens among normal peripheral blood cells make them attractive candidates for identifying changes in the status of immune activation.     

Thyroid function tests in children with congenital hypothyroidism on L-thyroxine treatment

The plasma levels of thyroxine (T4), triiodothyronine (T3), free T4 (FT4), free T3 (FT3), reverse T3 (rT3) and immunoradiometrically assayed thyrotropin (IRMA TSH) have been measured in 28 L-T4-treated children with congenital hypothyroidism as well as in a control group (group C). The patients were subdivided into 2 groups according to the nonsuppressed (group A) or suppressed (group B) TSH response to TSH-releasing hormone (TRH). Basal IRMA TSH correlated with the TSH increment after TRH and it was significantly lower in group B vs. groups A and C, while no difference was present between groups A and B in regard to T4, FT4 and rT3, all higher than in group C. FT3 levels were similar in the 3 groups. In children, as in adults, basal IRMA TSH seems to be a reliable index in monitoring overtreatment.     

城市垃圾堆肥对高羊茅生长及土壤性质的影响

采用盆栽实验方法,比较了在每盆施用130 g垃圾堆肥(T1)或1.5 g化肥(T2)以及130 g垃圾堆肥与1.5 g 化肥混合施用(T3)条件下高羊茅(Festuca arundinacea L)生长及土壤性质的变化.结果表明:T1和T3处理组的土壤容重显著低于对照(不施肥)和T2处理组,土壤中的阳离子代换量及有机质、碱解氮、速效磷和速效钾含量显著高于对照及T2处理组,且T3处理组的增加幅度更大;T1和T3处理组土壤中Pb、As、Cu、Cr和Cd含量均高于对照和T2处理组,且T1处理组土壤中Pb、As、Cu和Cd含量均显著高于仍处理组,但均小于土壤环境质量一级标准,不会造成土壤环境污染.T1和T3处理组高羊茅种子萌发率均明显低于T2处理组和对照,但随萌发时间的延长逐渐提高,表明垃圾堆肥对高羊茅种子萌发的抑制作用是暂时性的.施肥处理对高羊茅生长均有明显的促进作用;T1、T2和T3处理组高羊茅的株高、地上部分和根于质量、叶片N含量和叶绿素含量总体上均显著高于对照;其中T1处理组在栽培前期高羊茅的株高、地上部分干质量和叶片N含量低于T2处理组,但在后期显著高于T2处理组;而T3处理组高羊茅的各项指标总体上均最高.结果显示:使用垃圾堆肥能明显改善土壤性质、增加土壤肥力;垃圾堆肥具有缓释效应,能改善高羊茅的生长状况、提高草坪质量,与化肥混合施用效果更佳.     

Single or Combined Applications of Zinc and Multi-strain Probiotic on Intestinal Histomorphology of Broilers Under Cyclic Heat Stress

Two-hundred-eighty-day-old broiler chicks were divided into seven groups. The groups were designated as T1, thermoneutral zone; T2, heat stressed (HS); T3,     

Genetics of Treponema: relationship between Treponema pallidum and five cultivable treponemes.

Three genetically distinct groups of treponemes have been identified by saturation reassociation assays using 125I-labeled treponemal DNAs. The three groups are (i) virulent Treponema pallidum (Nichols strain), (ii) T. phagedenis and its biotypes Reiter and Kazan 5, and (iii) T. refringens biotypes Nichols and Noguchi. There is no detectable DNA sequence homology (less than 5%) among the three groups. The groups have distinct guanine + cytosine contents: 52.4 to 53.7% for T. pallidum, 41.5% for T. refringens, and 38 to 39% for T. phagedenis.     

Thyroxine induced stress and its possible prevention by catechin

Free radicals are all known to damage cell components. The present study was designed to evaluate the free radical generation in the testis and liver and also to determine the testicular and hepatic antioxidant enzyme activities with and without catechin administration in thyroxine induced male Sprague-Dawley rats. The experimental animals were divided into four groups, six on each division. L-thyroxine (T4) (0.3 mg/kg body weight) was administered to experimental groups for 15 days. Another group (CAT-T4) was administered with L-thyroxine (T4) in the dose as mentioned and catechin (100 mg/kg of body weight/day) simultaneously. Third group was administered only with catechin, and the remaining group was kept as control. Lipid peroxidation level (LPO) increased in L-thyroxine treated rats as compared to control, while LPO level was almost normal in L-thyroxine (T4) and catechin (CAT-T4) treated group. Superoxide dismutase (SOD) and catalase activities were increased in L-thyroxine (T4) treated rats as compared to control, where as there were almost at normal level in L-thyroxine (T4) and catechin (CAT-T4) treated groups. The results show that, thyroxine administration develops oxidative stress; the organism defends it against the effects of oxidative stress by increasing SOD and catalase activities as a protective mechanism and catechin, being an antioxidant, normalizes lipid peroxidation in testis and liver including SOD and catalase activities.     

Strength and power profiles of the lower and upper extremities in master throwers at different ages

Thirty-two master athletes (shot put, discus, and hammer throw) were divided into 4 groups according to their age (T40 [40 years of age], 50 [50 years of age], 60 [60 years of age], and 75 [75 years of age]). Twenty-eight age-matched men served as controls (C40 [40 years of age], 50 [50 years of age], 60 [60 years of age], and 75 [75 years of age]). The subjects were tested for maximal isometric strength of the lower and upper extremities. Power was measured by performing jump squats and bench press in the Smith machine with the load of 60% of 1 repetition maximum. Electromyographic (EMG) activity was recorded from 6 different muscles. The muscle thickness of vastus lateralis and intermedius (VL+VI) and triceps brachii (TB) was measured by ultrasound. Maximal strength differed (p < 0.05- 0.001) in all testing actions between T40 and T60 and T40 and T75 as well as between T and C groups. Both VL+VI and TB thickness in T40 was greater (p < 0.05-0.01) than in T60 and T75 and in T was larger than in C groups. Average force during the first 500 milliseconds (ms) was higher (p < 0.05-0.001) in T40 compared to T50, T60, and T75 in bilateral leg extension, biceps curl, and especially in unilateral knee flexion. T40 produced higher power than the other groups (p < 0.05-0.001). The relative agonist EMG activation (VL) in leg extension during the first 100 ms compared to maximum activation was lower (p < 0.05) in T50, T60, and T75, but not in T40. The present data indicate that maximal strength and muscle thickness as well as explosive strength and power characteristics decline with aging also in master athletes who carry out strength training and throwing exercises actively over several decades. Nevertheless, in master athletes, maximal strength and muscle mass as well as explosive force production of the upper and lower extremities seem to be at remarkably higher levels than those recorded for age-matched control men.