Meta-analysis comparing impact of age, sex and renal function on the efficacy and safety of new oral anticoagulants vs. vitamin K antagonists for the treatment of acute venous thromboembolisms

Background

New direct oral anticoagulants (NOACs), as a preferable treatment option for acute venous thromboembolism (VTE) have been recommended with practical advantages as compared to Vitamin K antagonists (VKAs) in clinical practice.

Purpose

In our study, we performed a meta-analysis to determine the efficacy and safety of NOACs vs. VKAs in patients with different age, sex and renal function for the treatment of VTE.

Methods

Electronic databases (accessed October 2019) were systematically searched to identify RCTs evaluating apixaban, dabigatran, edoxaban, and rivaroxaban versus VKAs for the treatment of acute venous thromboembolism.

Results

NOACs was associated with a borderline higher efficacy in female (OR 0.79, 95% CI 0.62–1.02), and a significantly higher efficacy in patients with age more than 75 (OR 0.51, 95% CI 0.32–0.80) and creatinine clearance less than 50 mL/min (OR 0.57, 95% CI 0.32–0.99). NOACs also show advantage in terms of major or clinically relevant non-major bleeding in male (OR 0.72, 95% CI 0.60–0.86), and patients with creatinine clearance more than 50 mL/min (OR 0.75, 95% CI 0.67–0.84).

Conclusions

NOACs have exhibited clinical preference among patients with acute VTE as compared to VKA with significantly decreased thrombosis events and lower bleeding complications, especially in patients with age more than 75 and creatinine clearance less than 50 mL/min.

Funding Acknowledgement

Type of funding source: Public Institution(s). Main funding source(s): This study was supported by the National Natural Science Foundation of China (81800390) and the Natural Science Foundation of Shaanxi province (2018KW067).

Piperine, a functional food alkaloid, exhibits inhibitory potential against TNBS-induced colitis via the inhibition of IκB-α/NF-κB and induces tight junction protein (claudin-1, occludin, and ZO-1) signaling pathway in experimental mice

BACKGROUND

Inflammatory bowel disease is a chronic immunoinflammatory disease of the gastrointestinal tract. Piperine, an alkaloid, has been reported to possess antioxidant, anti-inflammatory, antiapoptotic, and antiulcer potential.

AIM

To elucidate the plausible mechanisms of action of piperine on experimental trinitrobenzenesufonic acid (TNBS)-induced colitis by assessing various biochemical, molecular, histological, and ultrastructural modifications.

METHODS

Colitis was induced in male Sprague-Dawley rats via intrarectal instillation of TNBS. Then, the rats were treated with piperine (10, 20, and 40 mg/kg, p.o.) for 14 days.

RESULTS

TNBS induced significant (p < 0.05) colonic damage, which was assessed by disease activity index, macroscopic score, and stool consistency. The administration of piperine (20 and 40 mg/kg) significantly inhibited (p < 0.05) these damages. Treatments with piperine (20 and 40 mg/kg) notably inhibited (p < 0.05) the TNBS-induced elevation of oxido-nitrosative stress (superoxide dismutase, glutathione, malondialdehyde, and nitric oxide), 5-hydroxytryptamine, and hydroxyproline content in the colon. Furthermore, colonic inducible nitric oxide synthase (iNOs), tumor necrosis factor-alpha (TNF-α), interleukin (IL)-1β, IL-6, interferon-gamma, and cyclooxygenase-2 (COX-2) messenger RNA (mRNA) expressions were upregulated after TNBS instillation and piperine (20 and 40 mg/kg) significantly attenuated (p < 0.05) these elevated mRNA expressions. TNBS decreased the expressions of tight junction (TJ) protein (claudin-1, occludin, and zonula occludens-1 (ZO-1)) and increased the expressions of proapoptotic (caspase-1) protein. These expressions were markedly inhibited (p < 0.05) by piperine treatment. Histological and ultrastructural studies of transmission electron microscopy suggested that piperine significantly ameliorated (p < 0.05) TNBS-induced colonic aberrations.

CONCLUSION

Piperine ameliorated the progression of TNBS-induced colitis by modulating the nuclear factor of kappa light polypeptide gene enhancer in B-cells inhibitor-alpha/nuclear factor-kappa B signaling pathway, thus inhibiting the overexpression of proinflammatory cytokines (TNF-α and IL's), COX-2, iNOs, oxido-nitrosative stress, and proapoptotic proteins (caspase-1) that may improve the expression of TJ protein (claudin-1, occludin, and ZO-1).

[Renal clear cell carcinoma transferred to infratemporal fossa and pterygopalatine fossa: A case report]

SummaryRenal clear cell carcinoma is prone to distant metastasis, especially in the head and neck, but it is rare to transfer to infratemporal fossa and pterygopalatine fossa. We reported a 62-year-old male patient with complains of numbness and burning sensation on the left side of the face for more than 3 months. Left kidney removal was performed 8 years ago due to renal cancer. Preoperative enhancement CT showed a large blood-rich occupation in the left nasopharyngeal and pterygopalatine with adjacent paranasal sinus and skull base bone destruction. Under the general anesthesia, the anterior lacrimal recess approach was used for tumor resection. Preoperative interventional embolization of the feeding artery, intraoperative pathology, frozen section showed metastasis of renal cell carcinoma, and postoperative immunohistochemical examination, confirmed metastatic renal clear cell carcinoma（infratemporal fossa and pterygopalatine fossa）. The patients were transferred to the oncology department for further radiotherapy and chemotherapy.

DETECTION OF LACTOBACILLI IN MONTHLY MAIL-IN STOOL SAMPLES FROM 3-18 MONTHS OLD INFANTS AT GENETIC RISK FOR TYPE 1 DIABETES

The feasibility to detect lactobacilli in mail-in infant stools collected monthly from 3-18 months old children was investigated. The aim was to determine total lactobacilli and Lactobacillus plantarum (L. plantarum) content (ng/g feces) in 50 infants each from Colorado (648 samples), Finland (624 samples) and Sweden (685 samples) who participated in the TEDDY (The Environmental Determinants of Diabetes in the Young) study. Total lactobacilli content varied markedly between 5 and 16,800 ng/g feces in the three clinical sites within and between individuals especially in infants. L.plantarum also varied markedly intra- and inter-individually from <0.5 - 736 ng/g feces. A higher variability of total lactobacilli was found before 10 months of age than after in the three different clinical sites. Sweden had the lowest total lactobacilli content compared to Colorado and Finland while the L.plantarum content was higher in Sweden. Mail-in stool samples from infants should prove useful in analyzing probiotics in childhood.

Stress failure plays a major role in the development of high-altitude pulmonary oedema in rats

Hypoxia and exertion are considered as the two main factors in the development of high-altitude pulmonary oedema (HAPE), however its pathophysiology remains unclear. Therefore, we established a model in which 32 Sprague-Dawley rats were randomly assigned to normoxic rest, hypoxic rest, normoxic exercise and hypoxic exercise. An altitude of 4,700 m was simulated using hypobaric hypoxia, while exercise consisted 48 h walk with 15-20 min breaks every 4 h. Arterial blood gas, bronchoalveolar lavage (BAL), lung wet-to-dry weight (W/D) ratio and histological measurements were conducted on each animal. In rats exercising in hypoxia, BAL protein and lung W/D ratio were significantly increased but no changes in BAL leukotriene B(4) and immunoglobulin M were observed. In the same group, lung histology showed typical haemorrhagic lung oedema and disruption of both alveolar epithelium and capillary endothelium while hypoxia or exertion alone only induced slight endothelium and epithelium swelling/disruption. Our study established a direct link between histological and physiological evidence of HAPE-like symptoms and we demonstrated that hypoxia and exertion can synergistically induce HAPE-like symptoms in Sprague-Dawley rats without inducing lung inflammation. We therefore propose that alveolar epithelium and capillary endothelium stress failure play a major role in the development of HAPE.

Improving auscultatory blood pressure measurement with electronic and computer technology: the visual auscultation method

BACKGROUND

The auscultatory method is used as the reference standard in all prevalent protocols for validation of noninvasive blood pressure measuring devices, and a validation study is essentially based on the comparison between the device and observer measurements. Thus, the objectivity and accuracy of observer measurements are crucial to the validation result.

METHODS

To provide observers with more objective information about an auscultatory measurement so that sufficient information to make measurements with greater potential objectivity and accuracy can be available, a computerized data acquisition and analysis system has been developed. It cannot only acquire and store Korotkoff sound, cuff pressure, and oscillometric pulse signals, as well as the sphygmomanometer image, but it also can display the waveforms of the three signals and the sphygmomanometer video while playing the synchronous Korotkoff sounds. With this system, observers can make their measurements via the visual auscultation method, that is to say, by watching those waveforms, instead of the sphygmomanometer, while listening for synchronized Korotkoff sounds. The system was validated according to the International Protocol (IP).

RESULTS

The result showed that all the differences between system measurements by the visual auscultation method and observer measurements by the conventional auscultatory method were within 4 mm Hg.

CONCLUSIONS

The visual auscultation method achieved a high degree of accuracy, and human observers can be replaced by the system in the validation study of blood pressure measuring devices.

Early chronic aluminium exposure impairs long-term potentiation and depression to the rat dentate gyrus in vivo

As an important neurotoxin, aluminium can cause cognitive dysfunctions and mental diseases. Previous studies have reported that aluminium impaired long-term potentiation (LTP) in vivo and in vitro. Here, we utilise two models of synaptic plasticity, LTP and long-term depression (LTD) to study the effects of aluminium on synaptic plasticity in vivo. Neonatal Wistar rats were chronically exposed to aluminium from birth to weaning via the milk of dams fed with 0.3% aluminium chloride solution. Excitatory postsynaptic potential (EPSP) and population spikes (PS) were recorded from the dentate gyrus (DG) of adult rats by electrically stimulating the perforant path. THE FOLLOWING RESULTS WERE OBTAINED: (1) The input/output function indicated that, as compared to controls, aluminium increased the baseline amplitude of the PS, but decreased the baseline slope of EPSP. (2) Aluminium significantly prevented LTD in PS (controls: 77.36+/-6.7%, n=7; aluminium-exposed: 102.01+/-9.1%, n=7; P<0.05) and decreased the LTD amplitude in EPSP (controls: 76.61+/-4.1%, n=7; aluminium-exposed: 94.31+/-7.9% n=7, P<0.05). (3) Aluminium reduced the amplitude of LTP in both PS (controls: 190+/-16.1%, n=7; aluminium-exposed: 135+/-9.7%, n=7; P<0.05) and EPSP (control: 132+/-9.3%, n=7; aluminium-exposed: 115+/-10.6%, n=7; P<0.05). As for LTD and LTP, PS was impaired more seriously than EPSP in aluminium-exposed rats. (4) Aluminium exposure decreased the paired-pulse facilitation (PPF) of PS at 30-150 ms interpulse interval (IPI), and reduced 93.5% of PPF at 80 ms IPI in PS (controls: 243.4+/-39.8%, n=7; aluminium-exposed: 149.9+/-12.3%, n=7). There was no significant difference in EPSP of PPF. From these results we conclude that aluminium exposure in neonatal rats thus reduces the amplitude of LTP and PPF and blocks the induction of LTD in the DG. We suggest that aluminium affects both presynaptic and postsynaptic mechanisms of synaptic transmission.

Inhibitory effects of sodium quercetin monosulfate on pig platelet aggregation induced by thrombin

AIM

To study the inhibitory effects of sodium quercetin monosulfate (SQMS) on pig platelet aggregation induced by thrombin.

METHODS

Platelet aggregation was analyzed by turbidimetry. Cytosolic free calcium concentration ([Ca2+]i) was determined by Fura-2 fluorescence. Activity of protein kinase C (PKC) was assayed by incubating PKC with histone III S and [gamma-32 P] ATP. The cytoskeletal proteins were precipitated by Triton X-100 and separated by SDS-PAGE.

RESULTS

SQMS inhibited the platelet aggregation induced by thrombin 500 U.L-1 with IC50 132 (50-347) mumol.L-1. SQMS inhibited Ca2+ influx in blood platelets induced by thrombin 500 U.L-1 in the presence of extracellular Ca2+ 1 mmol.L-1 with IC50 20 (9-46) mumol.L-1; SQMS inhibited the internal Ca2+ release in the absence of extracellular Ca2+. SQMS also decreased [Ca2+]i level in quiescent blood platelets. SQMS (10-160 mumol.L-1) inhibited the activity of cytosolic PKC from blood platelets in a concentration-dependent manner, but had no effect on membrane PKC. SQMS (20-80 mumol.L-1) inhibited the actin polymerization induced by thrombin 500 U.L-1 inblood platelets in a concentration-dependent manner.

CONCLUSION

SQMS inhibited pig platelet aggregation induced by thrombin and its mechanism might be due to its inhibitions of Ca2+ influx, internal Ca2- release, PKC activity, and actin polymerization.

Generation of antigen-specific cytotoxic T lymphocytes and regulation of cytokine production takes place in the absence of CD3zeta

The TCR-associated protein CD3zeta plays a major role in regulating the state of responsiveness to peptide-MHC complexes on the surface of antigen-presenting cells. In this paper the requirement of CD3zeta in the generation of cytotoxic T cells was compared with its requirement in cytokine gene activation in two mutant mice: ZKO mice with a disrupted CD3zeta gene and ZTG mice in which a truncated CD3zeta segment was expressed as a transgene on the ZKO background. Upon infection of ZTG mice with lymphocytic choriomeningitis virus (LCMV), antigen-specific cytotoxic T lymphocyte (CTL) responses were detected, identical to responses in wild-type mice. In addition, antigen-specific CTL responses to allogeneic class I and class II MHC in ZTG animals were indistinguishable from those in wild-type animals. However, CTL responses to the same major antigens were not detectable in ZKO mice. We conclude that the signal transduction pathways leading to CTL development and cytokine production can be triggered through TCR in the absence of functional CD3zeta, provided the remainder of the TCR-CD3 complex is expressed at high levels on the cell surface. Surprisingly, IFN-gamma production in response to LCMV followed the same kinetics in ZKO, ZTG and wild-type mice. However, in vitro studies showed that cytokine production in general was abnormally regulated in T lymphocytes from ZKO mice, in contrast to ZTG T cells. Taken together, these studies support the hypothesis that development of CTL can take place in the absence of functional CD3zeta. However, CTL development requires stronger TCR-initiated signal transduction events than induction of cytokine genes.

T lymphocyte development in the absence of CD3 epsilon or CD3 gamma delta epsilon zeta

CD3 gamma, delta, epsilon, and zeta proteins together with the pre-TCR alpha-chain (pT alpha) and a rearranged TCR beta-chain assemble to form the pre-TCR that controls the double negative (DN) to double positive (DP) stages of thymopoiesis. The CD3 proteins are expressed before pT alpha and TCR beta-chains in prothymocytes and are expressed intracellularly in precursor NK cells, suggesting that the CD3 complex may function independent of pT alpha and TCR beta. In this report, both the role of CD3 epsilon exclusively, and the role of CD3 proteins collectively, in thymocyte and NK cell development were examined. In a mouse strain termed E delta P, a neomycin cassette inserted within the CD3 epsilon promoter abolishes CD3 epsilon and delta expression and also abolishes CD3 gamma expression in all but a small minority (< or =1%) of prothymocytes. These prothymocytes became deficient in CD3 epsilon alone upon reconstitution of CD3 delta expression and were severely, but not completely, arrested at the DN stage, as small numbers of double positive thymocytes were detected. In de facto CD3 gamma delta epsilon zeta(null) mice generated by crossing the epsilon delta P mice with CD3 zeta-/- mice, thymopoiesis were arrested at the CD44-CD25+ DN stage as observed in RAG-/- mice, DJ and VDJ recombination at the TCR beta locus was functional, and normal numbers of NK cells were detected. Together, the findings demonstrate that during thymocyte development, the CD3 complex collectively is not essential until the critical CD44-CD25+ DN stage in which pre-TCR begins to function, whereas CD3 epsilon is critical for the assembly of pre-TCR. Moreover, CD3 proteins are dispensable for NK cell development.

Analysis of breast milk to assess exposure to chlorinated contaminants in Kazakstan: high levels of 2,3,7, 8-tetrachlorodibenzo-p-dioxin (TCDD) in agricultural villages of southern Kazakstan

To assess levels of chlorinated contaminants in breast milk, we measured organochlorine pesticides, polychlorinated biphenyls, polychlorinated dibenzo-p-dioxins (PCDDs), and polychlorinated dibenzofurans (PCDFs) in breast milk samples collected in 1994 according to the World Health Organization protocol from 92 donors that were representative of regional populations in southern Kazakstan. High levels (10-120 pg/g fat) of 2,3,7, 8-tetrachlorodibenzo-p-dioxin (TCDD), the most toxic of the PCDD/PCDF congeners, were found in breast milk samples from an agricultural region. TCDD was the major contributor (75%) to the international toxicity equivalents of these samples. The same distinctive PCDD/PCDF congener pattern was found in 15 breast milk samples and 4 serum samples collected in 1996 in a follow-up study, and has now been confirmed by three analytical laboratories.

Expression of a CD3 epsilon transgene in CD3 epsilon(null) mice does not restore CD3 gamma and delta expression but efficiently rescues T cell development from a subpopulation of prothymocytes

The TCR-associated CD3 complex consists of four subunits, i.e. CD3 gamma, delta, epsilon and zeta, which are expressed very early in T cell development prior to the expression of the TCR and the pre-TCR alpha chain. It is unclear whether the expression of each CD3 protein is independent of, or is influenced by, other CD3 subunits. To study whether CD3 epsilon regulates expression of CD3 gamma and delta genes, we generated a strain of CD3 epsilon-deficient mice termed CD3 epsilon(delta P/delta P) (epsilon(delta P)), in which the promoter of CD3E was disrupted, and subsequently reconstituted these mice with a CD3 epsilon transgene. In the epsilon(delta P) mice, T cell development is arrested at the double-negative stage and targeting the CD3 epsilon gene caused severe inhibition of CD3 gamma and delta gene expression. Introduction of the CD3 epsilon transgene did not restore CD3 gamma and delta expression. However, a very small fraction of prothymocytes that expressed CD3 gamma and delta was rescued upon reconstitution of the CD3 epsilon transgene. Remarkably, this rescue led to a very efficient differentiation and maturation of thymocytes, resulting in a significant T cell population in the periphery. These results demonstrate that CD3 epsilon does not regulate expression of CD3 gamma and delta genes, and underscore the capacity of each prothymocyte to give rise to a large number of mature peripheral T cells.

Activation-induced apoptosis of mature T cells is dependent upon the level of surface TCR but not on the presence of the CD3 zeta ITAM

Activation-induced cell death (AICD) occurs primarily in recently activated T cells after a second TCR triggering. Since a threshold in the activation status may be critical for AICD, it is likely that the CD3 ITAM, docking sites for tyrosine kinases, regulate AICD. A 'threshold model' for AICD was tested by using two targeted mutant mouse strains lacking either the zeta chain (CD3zeta-/-) or the ITAM of the zeta chain (CD3zeta-/-:Tgzetadelta67-150). Although the T cells from the CD3zeta-/- mice express extremely low levels of surface TCR, a subpopulation (approximately 18%) of activated T cells could be induced to express TCR/FcepsilonRI gamma by using a powerful polyclonal activation protocol. These activated TCR/FcRI gamma T cells were capable of undergoing AICD, but its induction required 10 times as much anti-CD3epsilon mAb as that required for AICD of wild-type T cells. Thus, the intensity of AICD correlated with the level of CD3 expression and was less efficient with activated, CD3zeta(-/-)-derived T cells. By contrast, AICD of T cells from the CD3zeta-/-:Tgzetadelta67-150 mice could be induced with low doses of anti-CD3epsilon mAb and the extent of AICD was comparable to T cells from wild-type mice. The AICD induced in T cells from CD3-/-, CD3zeta-/-:Tgzetadelta67-150 and normal controls was specifically inhibited by Fas-Ig fusion proteins. Our data support the 'threshold model' of AICD by demonstrating that AICD is controlled by the strength of T cell activation.

Essential and partially overlapping role of CD3gamma and CD3delta for development of alphabeta and gammadelta T lymphocytes

CD3gamma and CD3delta are two highly related components of the T cell receptor (TCR)-CD3 complex which is essential for the assembly and signal transduction of the T cell receptor on mature T cells. In gene knockout mice deficient in either CD3delta or CD3gamma, early thymic development mediated by pre-TCR was either undisturbed or severely blocked, respectively, and small numbers of TCR-alphabeta+ T cells were detected in the periphery of both mice. gammadelta T cell development was either normal in CD3delta-/- mice or partially blocked in CD3gamma-/- mice. To examine the collective role of CD3gamma and CD3delta in the assembly and function of pre-TCR and in the development of gammadelta T cells, we generated a mouse strain with a disruption in both CD3gamma and CD3delta genes (CD3gammadelta-/-). In contrast to mice deficient in either CD3gamma or CD3delta chains, early thymic development mediated by pre-TCR is completely blocked, and TCR-alphabeta+ or TCR-gammadelta+ T cells were absent in the CD3gammadelta-/- mice. Taken together, these studies demonstrated that CD3gamma and CD3delta play an essential, yet partially overlapping, role in the development of both alphabeta and gammadelta T cell lineages.

Congener-specific analysis of PCBs in human milk from Kazakhstan

We have characterized the spectrum of PCB contaminants in human milk samples from 95 women in Kazakhstan using GC/MS congener specific analysis. In these samples, 12 PCBs comprised 83% of total PCB concentration, and were similar to the major PCBs reported in other published human milk studies. By summing concentration levels of 80 PCB congeners in the Kazakhstan samples, a mean total PCB concentration of 368 ng/g fat was obtained. This is lower than levels reported in human milk samples from Western Europe. Six indicator PCBs were summed in Kazakh milk samples; their aggregate value was similar to literature values published for human milk from the former Soviet Union. Using WHO's recent TEF scheme, the mean sum of PCDD/F, coplanar PCB, mono-ortho PCB, and di-ortho PCB TEQ is 42 pg TEQ/g fat.

Analysis of breast milk to assess exposure to chlorinated contaminants in Kazakstan: PCBs and organochlorine pesticides in southern Kazakstan

Organochlorine pesticides (OC) and polychlorinated biphenyls (PCBs) were measured in samples of breast milk taken from 92 donors representative of regional populations in southern Kazakstan. The World Health Organization protocol for assessing levels of chlorinated contaminants in breast milk was followed. The most prevalent OC residues were beta-hexachlorocyclohexane (beta-HCH), p,p'-DDE, p,p'-DDT, hexachlorobenzene, and alpha-HCH. The measured levels of beta-HCH were among the highest reported in the published literature. Data from Aralsk, near the Aral Sea, indicated continuing DDT exposure. Overall PCB-toxic equivalent levels (22 pg/g fat) were similar to those reported in industrialized European countries. PCBs were highest in Atyrau in the Caspian oilfields.

CD16-expressing CD8alpha alpha+ T lymphocytes in the intestinal epithelium: possible precursors of Fc gammaR-CD8alpha alpha+ T cells

T lymphocytes normally express their Ag receptors in association with the CD3 proteins, which include CD3zeta. In CD3zeta eta(null) mice thymic and peripheral T lymphocytes do not express the TCR/CD3 complex on their surface due to retention in the endoplasmic reticulum of the remaining polypeptide chains. However, intestinal intraepithelial lymphocytes (iIEL) of CD3zeta eta(null) mice do express surface TCR, because the Fc epsilonRI gamma chain replaced the CD3zeta chain in the TCR/CD3 complex. Here we report that in a subset of CD8alpha alpha+ iIEL the presence of the Fc epsilonRI gamma chain could be accounted for by the surface expression of the Fc gammaRIII(CD16) complex. Because in wild-type (wt) mice only CD16+ iIEL coexpressed Fc epsilonRI gamma and CD3zeta, we concluded that the presence of Fc epsilonRI gamma was dictated by its required participation of CD16 complex. CD8alpha alpha+ iIEL bearing CD16 and B220 were also detected in the intestinal mucosa of RAG-2(null) mice from 12 days after birth onward. Two independent experimental settings were used in an attempt to demonstrate that CD16+ iIEL matured into CD16- T cells. First, in the RAG-2(null) mice, iIEL responded to in vivo administration of an anti-CD3epsilon mAb by progression to a more mature stage of development, characterized by a loss of CD16 and B220. Secondly, a conversion to CD16- iIEL occurred upon transfer of wt CD16+ iIEL into RAG-2(null) mice. We conclude from these experiments that in both RAG-2(null) and wt mice, a precursor/progeny relationship may exists between CD16+ B220+ CD8alpha alpha+ and CD16- B220- CD8alpha alpha+ iIEL.

CD16-expressing CD8alpha alpha+ T lymphocytes in the intestinal epithelium: possible precursors of Fc gammaR-CD8alpha alpha+ T cells

T lymphocytes normally express their Ag receptors in association with the CD3 proteins, which include CD3zeta. In CD3zeta eta(null) mice thymic and peripheral T lymphocytes do not express the TCR/CD3 complex on their surface due to retention in the endoplasmic reticulum of the remaining polypeptide chains. However, intestinal intraepithelial lymphocytes (iIEL) of CD3zeta eta(null) mice do express surface TCR, because the Fc epsilonRI gamma chain replaced the CD3zeta chain in the TCR/CD3 complex. Here we report that in a subset of CD8alpha alpha+ iIEL the presence of the Fc epsilonRI gamma chain could be accounted for by the surface expression of the Fc gammaRIII(CD16) complex. Because in wild-type (wt) mice only CD16+ iIEL coexpressed Fc epsilonRI gamma and CD3zeta, we concluded that the presence of Fc epsilonRI gamma was dictated by its required participation of CD16 complex. CD8alpha alpha+ iIEL bearing CD16 and B220 were also detected in the intestinal mucosa of RAG-2(null) mice from 12 days after birth onward. Two independent experimental settings were used in an attempt to demonstrate that CD16+ iIEL matured into CD16- T cells. First, in the RAG-2(null) mice, iIEL responded to in vivo administration of an anti-CD3epsilon mAb by progression to a more mature stage of development, characterized by a loss of CD16 and B220. Secondly, a conversion to CD16- iIEL occurred upon transfer of wt CD16+ iIEL into RAG-2(null) mice. We conclude from these experiments that in both RAG-2(null) and wt mice, a precursor/progeny relationship may exists between CD16+ B220+ CD8alpha alpha+ and CD16- B220- CD8alpha alpha+ iIEL.

CD3-epsilon overexpressed in prothymocytes acts as an oncogene

BACKGROUND

Upon engagement of the T cell receptor for antigen, its associated CD3 proteins recruit signal transduction molecules, which in turn regulate T lymphocyte proliferation, apoptosis, and thymocyte development. Because some signal transducing molecules recruited by CD3-epsilon, i.e., p56lck and p59fyn, are oncogenic and since we previously found that overexpression of CD3-epsilon transgenes causes a block in T lymphocyte and NK cell development, we tested the hypothesis that aberrant CD3-epsilon signaling leads both to abnormal T lymphocyte death and lymphomagenesis.

MATERIALS AND METHODS

Ten independently derived transgenic mouse lines were generated with four different genomic CD3-epsilon constructs. Mice either homozygous or hemizygous for each transgene were analyzed for an arrest in T lymphocyte development and for the occurrence of T cell lymphomas.

RESULTS

Aggressive clonal T cell lymphomas developed at very high frequencies in seven mouse lines with intermediate levels of copies of CD3-epsilon derived transgenes. However, these lymphomas were not found when high copy numbers of CD3-epsilon transgenes caused a complete block in early thymic development or when a transgene was used in which the exons coding for the CD3-epsilon protein were deleted. Analyses of a series of double mutant mice, tgCD3-epsilon x RAG-2null, indicated that lymphomagenesis was initiated in lineage-committed prothymocytes, i.e., before rearrangement of the T cell receptor genes. In addition, the transgene coding for the CD3-epsilon cytoplasmic domain and its transmembrane region induced a T cell differentiation signal in premalignant tgCD3-epsilon x RAG-2null mice.

CONCLUSION

The nonenzymatic CD3-epsilon protein acted as a potent oncogene when overexpressed early in T lymphocyte development. Lymphomagenesis was dependent on signal transduction events initiated by the cytoplasmic domain of CD3-epsilon.

Numerical simulation of collapsible-tube flows with sinusoidal forced oscillations

Collapsible-tube flow with self-excited oscillations has been extensively investigated. Though physiologically relevant, forced oscillation coupled with self-excited oscillation has received little attention in this context. Based on an ODE model of collapsible-tube flow, the present study applies modern dynamics methods to investigate numerically the responses of forced oscillation to a limit-cycle oscillation which has topological characteristics discovered in previous unforced experiments. A devil's staircase and period-doubling cascades are presented with forcing frequency and amplitude as control parameters. In both cases, details are provided in a bifurcation diagram. Poincaré sections, a frequency spectrum and the largest Lyapunov exponents verify the existence of chaos in some circumstances. The thin fractal structure found in the strange attractors is believed to be a result of high damping and low stiffness in such systems.

[Induced-expression of MHC-DR molecules on mice islet cells]

The correlation of induced-expression of MHC-DR molecules with insulin release in cultured mice islet cells has been studied. The results showed that, (1) No detectable induced-expression of MHC-DR molecules by TNF-alpha alone at the concentration of 50-100 U/ml has been assayed, but the induced-expression of MHC-DR molecules has been identified in a few islet cells (8.5 +/- 2.9%) with IFN-r alone at concentration of 50-100 U/ml. (2) The induced-expression of MHC-DR molecules has been detected in as high as 80% of cultured islet cells with TNF-alpha and IFN-r combined at different concentrations. (3) Insulin released from cultured islet cells was enhanced by IFN-r and TNF-alpha either alone or combined at different concentrations. These results suggest that the induced-expression of MHC-DR molecules themselves does not damage the function for insulin release in cultured islet cells.

Analysis of the effects of measurement errors on the evaluation of propagation coefficients, in rubber tubes and canine aorta in vivo

Published measurements of canine arterial propagation coefficients show large disparities in pulse wave attenuation and considerable variation with frequency, suggesting both random and systematic error. Here we devise methods of assessing the likely magnitude of each measurement error source, and calculate the individual and cumulative effects on the propagation coefficients derived using three different schemes to compensate for reflections: the three-point method (3PT), the total occlusion method (OCC) and the general iterative method applied to Cox's arrangement of four transducers (GEN). Results from measurements using impulse excitation in a latex tube show that each method accumulates error in a characteristic frequency pattern. The predicted error bands for OCC are very small except at the fundamental, and clearly exclude a significant further error component. The predicted 3PT error is large at low and at high frequency, and the error bands are better predictors of actual error than in the OCC case. Transducer position error is less than any one of the three pressure measurement errors. The predicted GEN error increases with frequency and when averaged across frequency is of magnitude intermediate between those for OCC and 3PT. Results for the OCC and GEN methods from the canine aorta in vivo generally confirm these trends, but the concentration of natural pulse wave energy at low frequencies acts to reduce low-frequency error and increase high-frequency error.

Composition of TCR-CD3 complex in human intestinal intraepithelial lymphocytes: lack of Fc epsilon RI gamma chain

Human intestinal intraepithelial lymphocytes (iIEL) are a unique population of predominantly CD8 alpha beta+, TCR alpha beta+ lymphocytes and, to a lesser extent, TCP gamma delta+ lymphocytes that proliferate poorly to anti-CD3 mitogenic signals but display significant cytolytic activity. Studies in mouse model systems have shown that the gamma chain of the high-affinity receptor for IgE (Fc epsilon RI gamma) may substitute for the zeta chain in the TCR-CD3 complex of iIEL. This has suggested that the functional properties of these cells may be associated with an altered composition of the TCR-CD3 complex. We therefore analyzed the TCR-CD3 complex of normal human iIEL. One- and two-dimensional non-reducing/reducing SDS-PAGE analysis of CD3 gamma, CD3 delta, CD3 epsilon, zeta and Fc epsilon RI gamma chain immunoprecipitates of cell surface radiolabeled proteins with subunit-specific antibodies revealed a TCR-CD3 complex without associated Fc epsilon RI gamma chains. Thus, normal human iIEL contain a TCR-CD3 complex that consists predominantly of zeta homodimers in association with the alpha beta TCR and CD3 gamma, delta and epsilon, similar to the majority of peripheral lymphocytes. This indicates that the distinct properties of human iIEL are not associated with substitutions of the Fc epsilon RI gamma chain in the TCR-CD3 complex.

Severe colitis in mice with aberrant thymic selection

Tg epsilon 26 mice display an arrest very early in T cell development that has a profound effect on the architecture of thymic stromal cells. We have recently demonstrated that transplantation of wild-type bone marrow cells restores the thymic microenvironment of fetal but not adult Tg epsilon 26 mice. Here, we report that T cell-reconstituted adult Tg epsilon 26 mice develop a spontaneous wasting syndrome characterized by extensive inflammation of the colon, resembling human ulcerative colitis. Colitis in these animals was marked by substantial infiltration of the colon by activated thymus-derived CD4+ T cells. Importantly, bone marrow-transplanted Tg epsilon 26 mice previously engrafted with a fetal Tg epsilon 26 thymus did not develop colitis. These results suggest that T cells selected in an aberrant thymic microenvironment contain a population of cells able to induce severe colitis that can be prevented by T cells that have undergone normal thymic development.

Dynamic characteristics of prosthetic heart valves

The relation between flow rate (Q) and transvalvular pressure-drop (DP) is of fundamental importance for a prosthetic heart valve tested in steady flow conditions. The Q-DP plot can thus be called the static characteristic of the valve. While in pulsatile flow, with time (t) as a parameter, the instantaneous Q(t)-DP(t) relation can also be obtained. The Q-DP relation forms a phase graph on an X-Y plane during a whole cardiac cycle, and can be regarded as the dynamic characteristic, which to our knowledge has never been systematically explored before. With in vitro experiment the Q(t)-DP(t) relations are presented for five different aortic valves. Properly modelling the characteristics of heart valves is a key link in modelling the interactions between the ventricle and arterial system. Treatments for valves, such as diode analogue and orifice area assumption governed by the Gorlin formula, are found unsatisfactory. A simple one-dimensional flow equation is used to further examine the Q-DP graph, and both the dynamic resistance characteristic and the dynamic flow characteristic can be obtained. It is found that the dynamic characteristic differs from the static one not only in the inertance effect but also in the transient process, which can be quite energy-consuming and therefore important. Geometric relations of these phase graphs with the transvalvular power loss are discussed. The method of dynamic characteristics provides a new way to evaluate the performance of a tested valve.

Over-expression of CD3 epsilon transgenes blocks T lymphocyte development

We have reported previously that mice carrying > 30 copies of the human CD3 epsilon transgene completely lose their T lymphocytes and NK cells (36). Here we demonstrate by immunohistology that in the most severely immunodeficient mouse, tg epsilon 26, the thymus is very small, has sizeable vacuoles and does not contain recognizable T lymphocytes except for a small percentage of Thy-1+ cells and B cells. Cell surface phenotyping and TCR alpha and -beta rearrangement studies confirm that the arrest in T lymphocyte development precedes the arrest in rag-1null, rag-2null and TCR beta nuli mice. Since the T cell progenitors in which the arrest occurred were absent in the transgenic mice, indirect approaches were taken to examine the causes of the block in T cell development. Analyses of 12 independently established mutant mouse lines, generated with five different transgenic constructs, revealed that the severity of the abrogation in T cell development was dependent on the number of copies of transgenes. Since the number of transgene copies generally correlated with the levels of expression of the transgenic CD3 epsilon proteins, we concluded that over-expression of the CD3 epsilon protein was the likely cause of the block in T lymphocyte development. The T cell immunodeficiency was caused by either the human or the murine CD3 epsilon protein. Since transgene coded mRNAs were found in significantly higher quantities than endogenous CD3 epsilon mRNAs in fetal thymi on days 13 and 14 of gestation, over-expression took place very early in development, probably prematurely. Over-expression of the CD3 epsilon transgene in thymocyte precursors may therefore affect T lymphocyte development in the absence of TCR and possibly in the absence of the other CD3 proteins. More importantly, over-expression of the CD3 epsilon protein in thymocytes of mice with a low copy number of transgenes had a significant effect on late thymic development. Over-expression of the CD3 epsilon protein in immature thymocytes mimicked the effects caused by exposure of CD4- CD8- thymocytes to anti-CD3 epsilon treatment: apoptosis and lack of TCR beta expression. We therefore speculate that in the homozygous tg epsilon 26 animals the arrest in T cell development was caused by excessive signal transduction events rather than by a toxic effect of the transgenic protein.

Selection of peripheral and intestinal T lymphocytes lacking CD3 zeta

The CD3 zeta chain of the TCR plays a pivotal role in the activation of T cell responses toward foreign antigen and in the selection of the T cell repertoire. T lymphocytes from mice deficient in CD3 zeta (CD3 zeta/eta-/- mice) express very few cell surface TCR-CD3 complexes, and these animals have poorly developed thymuses which lack single-positive CD8 and CD4 thymocytes. Nevertheless, a substantial number of single-positive CD4+ and CD8+ T lymphocytes are found in peripheral lymphoid organs of CD3 zeta/eta-/- animals. Using double-mutant mice, generated by breeding CD3 zeta/eta-/- mice with others deficient in the expression of either class I or class II MHC molecules, we demonstrate here that positive selection of peripheral CD4+ and CD8+ T lymphocytes can occur in the absence of CD3 zeta/eta molecules. Analysis of the intestinal intra-epithelial lymphocytes from CD3 zeta/eta-/- mice revealed a novel T cell population expressing high levels of an alternative TCR alpha beta, due to the replacement of CD3 zeta by Fc epsilon RI gamma. Developmentally, these cells also depend on class I MHC expression. In contrast, TCR gamma delta/Fc epsilon RI gamma+ T cells develop independently of MHC class I or class II molecules. These experiments demonstrate that the unique subset of intestinal TCR alpha beta/Fc epsilon RI gamma+ lymphocytes is developmentally dependent on MHC expression. The restricted expression of TCR alpha beta/Fc epsilon RI gamma+ cells in the intestinal mucosa (rather than the thymus or lymph nodes) supports the hypothesis that selection of these T cells occurs extrathymically.

A block in both early T lymphocyte and natural killer cell development in transgenic mice with high-copy numbers of the human CD3E gene

A severe immunodeficiency involving a complete loss of T lymphocytes and natural killer cells was observed in independent lines of transgenic mice containing > 30 copies of the human CD3E gene (pL12). T-cell- natural killer (NK)- mice could also be generated by using a gene fragment pL12 delta 1 (without exons 4A and 5) coding for the CD3-epsilon transmembrane region and its 55-amino acid nonenzymatic cytoplasmic tail. The abnormally small thymus gland in the homozygous transgenic animals, which was approximately 1% the size of a wild-type thymus, contained only a few (2-4%) prethymocytes with a Thy-1+Pgp-1+IL-2R alpha- CD3-4-8- phenotype. In mice with lower copy numbers of the transgene thymocyte development was blocked at the Thy-1+Pgp-1-IL-2R alpha+CD3-4-8- stage, and normal NK activity was detected. Mice generated with high-copy numbers of a transgene pL12 delta 2 (pL12 delta 1 minus exons 6), coding for a truncated protein from which the CD3-epsilon extracellular domain, its transmembrane region, and most of its cytoplasmic region were absent, contained normal numbers of T lymphocytes and NK cells. These transgene effects suggested that recruitment of signal-transduction molecules by the cytoplasmic tail of this protein played an important role in the abrogation of both lineages. Taken together these observations support the notion that T lymphocytes and NK cells stemmed from a common precursor.

Abnormal T cell development in CD3-zeta-/- mutant mice and identification of a novel T cell population in the intestine

The T cell antigen receptor (TCR)-associated invariable membrane proteins (CD3-gamma, -delta, -epsilon and -zeta) are critical to the assembly and cell surface expression of the TCR/CD3 complex and to signal transduction upon engagement of TCR with antigen. Disruption of the CD3-zeta gene by homologous recombination resulted in a structurally abnormal thymus which primarily contained CD4- CD8- and TCR/CD3very lowCD4+CD8+ cells. Spleen and lymph nodes of CD3-zeta-/- mutant mice contained a normal number and ratio of CD4+ and CD8+ single positive cells that were TCR/CD3very low. These splenocytes did not respond to antibody cross-linking or mitogenic triggering. The V beta genes of CD4-CD8- and CD4+CD8+ thymocytes and splenic T cells were productively rearranged. These data demonstrated that (i) in the absence of the CD3-zeta chain, the CD4- CD8- thymocytes could differentiate to CD4+CD8+ TCR/CD3very low thymocytes, (ii) that thymic selection might have occurred, (iii) but that the transition to CD4+CD8- and CD4-CD8+ cells took place at a very low rate. Most strikingly, intraepithelial lymphocytes (IELs) isolated from the small intestine or the colon expressed normal levels of TCR/CD3 complexes on their surface which contained Fc epsilon RI gamma homodimers. In contrast to CD3-zeta containing IELs, these cells failed to proliferate after triggering with antibody cross-linking or mitogen. In comparison to thymus-derived peripheral T cells in the spleen and lymph nodes, the preferential expression of normal levels of TCR/CD3 in intestinal IELs suggested they mature via an independent extrathymic pathway.

Analysis of all possible combinations of four measurements determining true propagation in arteries

All possible combinations of four measurements of blood pressure, blood flow and vascular diameter are examined by transmission-line theory. It is found that only nine measurement combinations can give the attenuation coefficient gamma, reflection coefficient R and characteristic impedance Z0 simultaneously. At least one pressure measurement must be included. Their general expressions with arbitrary measuring locations are presented, together with some simplified forms which cover all the previous methods. A greater choice of method is thereby made available for use in practice. The results show that, regardless of the measurement locations, all combinations can be solved in the order gamma first, R second and Z0 last.

Labeling of adenine and guanine nucleotide-binding proteins in permeabilized cells with in situ periodate-oxidized nucleotides

A novel approach for identification of adenine and guanine nucleotide-binding proteins in permeabilized cells is described. Cells were incubated for various periods with alpha-32P-labeled nucleotides and then briefly treated with periodate. Condensation products formed in situ between the protein bound alpha-32P-labeled oxidized nucleotide (NTPoxi) and a lysine residue near the nucleotide-binding sites were rapidly stabilized by the addition of cyanoborohydride. Analysis by two-dimensional isoelectric focusing/sodium dodecylsulfate-poly-acrylamide gel electrophoresis showed that in the human leukemic T-cell line Jurkat a number of distinct intracellular proteins could be labeled with ATPoxi (M(r) 40,000-200,000) or GTPoxi (M(r) 19,000-80,000). Competition with deoxyribonucleotides confirmed the selectivity of these affinity labeling reactions. To test this method two classical GTP-binding proteins were further examined. First the alpha-subunits of the Gs and Gi-2 proteins were specifically labeled with [alpha-32P]GTPoxi but not with [alpha-32P]ATPoxi. Second, p21ras was crosslinked specifically to [alpha-32P]GTPoxi or to its bound endogenous ligand. Surprisingly, under optimized conditions 60% of the ras protein was specifically modified, demonstrating the high efficiency and sensitivity of the method. As a first step toward isolation of hitherto unidentified nucleotide-binding proteins, rabbit antisera specific for the modified amino acid residues were raised. The presented labeling method can be applied for identification of nucleotide-binding proteins in all eukaryotic cells.