Hyperon Polarization along the Beam Direction Relative to the Second and Third Harmonic Event Planes in Isobar Collisions at sqrt[s_{NN}]=200 GeV

The polarization of Λ and Λ[over ¯] hyperons along the beam direction has been measured relative to the second and third harmonic event planes in isobar Ru+Ru and Zr+Zr collisions at sqrt[s_{NN}]=200  GeV. This is the first experimental evidence of the hyperon polarization by the triangular flow originating from the initial density fluctuations. The amplitudes of the sine modulation for the second and third harmonic results are comparable in magnitude, increase from central to peripheral collisions, and show a mild p_{T} dependence. The azimuthal angle dependence of the polarization follows the vorticity pattern expected due to elliptic and triangular anisotropic flow, and qualitatively disagrees with most hydrodynamic model calculations based on thermal vorticity and shear induced contributions. The model results based on one of existing implementations of the shear contribution lead to a correct azimuthal angle dependence, but predict centrality and p_{T} dependence that still disagree with experimental measurements. Thus, our results provide stringent constraints on the thermal vorticity and shear-induced contributions to hyperon polarization. Comparison to previous measurements at RHIC and the LHC for the second-order harmonic results shows little dependence on the collision system size and collision energy.

Measurements of the Elliptic and Triangular Azimuthal Anisotropies in Central ^{3}He+Au, d+Au and p+Au Collisions at sqrt[s_{NN}]=200 GeV

The elliptic (v_{2}) and triangular (v_{3}) azimuthal anisotropy coefficients in central ^{3}He+Au, d+Au, and p+Au collisions at sqrt[s_{NN}]=200  GeV are measured as a function of transverse momentum (p_{T}) at midrapidity (|η|<0.9), via the azimuthal angular correlation between two particles both at |η|<0.9. While the v_{2}(p_{T}) values depend on the colliding systems, the v_{3}(p_{T}) values are system independent within the uncertainties, suggesting an influence on eccentricity from subnucleonic fluctuations in these small-sized systems. These results also provide stringent constraints for the hydrodynamic modeling of these systems.

Observation of Directed Flow of Hypernuclei _{Λ}^{3}H and _{Λ}^{4}H in sqrt[s_{NN}]=3 GeV Au+Au Collisions at RHIC

We report here the first observation of directed flow (v_{1}) of the hypernuclei _{Λ}^{3}H and _{Λ}^{4}H in mid-central Au+Au collisions at sqrt[s_{NN}]=3  GeV at RHIC. These data are taken as part of the beam energy scan program carried out by the STAR experiment. From 165×10^{6} events in 5%-40% centrality, about 8400 _{Λ}^{3}H and 5200 _{Λ}^{4}H candidates are reconstructed through two- and three-body decay channels. We observe that these hypernuclei exhibit significant directed flow. Comparing to that of light nuclei, it is found that the midrapidity v_{1} slopes of _{Λ}^{3}H and _{Λ}^{4}H follow baryon number scaling, implying that the coalescence is the dominant mechanism for these hypernuclei production in the 3 GeV Au+Au collisions.

Beam Energy Dependence of Triton Production and Yield Ratio (N_{t}×N_{p}/N_{d}^{2}) in Au+Au Collisions at RHIC

We report the triton (t) production in midrapidity (|y|<0.5) Au+Au collisions at sqrt[s_{NN}]=7.7-200  GeV measured by the STAR experiment from the first phase of the beam energy scan at the Relativistic Heavy Ion Collider. The nuclear compound yield ratio (N_{t}×N_{p}/N_{d}^{2}), which is predicted to be sensitive to the fluctuation of local neutron density, is observed to decrease monotonically with increasing charged-particle multiplicity (dN_{ch}/dη) and follows a scaling behavior. The dN_{ch}/dη dependence of the yield ratio is compared to calculations from coalescence and thermal models. Enhancements in the yield ratios relative to the coalescence baseline are observed in the 0%-10% most central collisions at 19.6 and 27 GeV, with a significance of 2.3σ and 3.4σ, respectively, giving a combined significance of 4.1σ. The enhancements are not observed in peripheral collisions or model calculations without critical fluctuation, and decreases with a smaller p_{T} acceptance. The physics implications of these results on the QCD phase structure and the production mechanism of light nuclei in heavy-ion collisions are discussed.

Hemorrhagic morbidity in nulliparous patients with placenta previa without placenta accrete spectrum disorders

Background

Placental adhesion spectrum (PAS) is a disease in which the trophoblast invades the myometrium, and is a well-known high-risk condition associated with placental previa.

Aim

The morbidity of nulliparous women with placenta previa without PAS disorders is unknown.

Patients and Methods

The data from nulliparous women who underwent cesarean delivery were collected retrospectively. The women were dichotomized into malpresentation (MP) and placenta previa groups. The placenta previa group was categorized into previa (PS) and low-lying (LL) groups. When the placenta covers the internal cervical os, it is called placenta previa, when the placenta is near the cervical os, it is called the low-lying placenta. Their maternal hemorrhagic morbidity and neonatal outcomes were analyzed and adjusted using multivariate analysis based on univariate analysis.

Results

A total of 1269 women were enrolled: 781 women in the MP group and 488 women in the PP-LL group. Regarding packed red blood cell transfusion, PP and LL had adjusted odds ratio (aOR) of 14.7 (95% confidence interval (CI): 6.6 - 32.5), and 11.3 (95% CI: 4.9 - 26) during admission, and 51.2 (95% CI: 22.1 - 122.7) and 10.3 (95% CI: 3.9 - 26.6) during operation, respectively. For intensive care unit admission, PS and LL had aOR of 15.9 (95% CI: 6.5 - 39.1) and 3.5 (95% CI: 1.1 - 10.9), respectively. No women had cesarean hysterectomy, major surgical complications, or maternal death.

Conclusion

Despite placenta previa without PAS disorders, maternal hemorrhagic morbidity was significantly increased. Thus, our results highlight the need for resources for those women with evidence of placenta previa including a low-lying placenta, even if those women do not meet PAS disorder criteria. In addition, placenta previa without PAS disorder was not associated with critical maternal complications.

Measurement of Sequential ϒ Suppression in Au+Au Collisions at sqrt[s_{NN}]=200 GeV with the STAR Experiment

We report on measurements of sequential ϒ suppression in Au+Au collisions at sqrt[s_{NN}]=200  GeV with the STAR detector at the Relativistic Heavy Ion Collider (RHIC) through both the dielectron and dimuon decay channels. In the 0%-60% centrality class, the nuclear modification factors (R_{AA}), which quantify the level of yield suppression in heavy-ion collisions compared to p+p collisions, for ϒ(1S) and ϒ(2S) are 0.40±0.03(stat)±0.03(sys)±0.09(norm) and 0.26±0.08(stat)±0.02(sys)±0.06(norm), respectively, while the upper limit of the ϒ(3S) R_{AA} is 0.17 at a 95% confidence level. This provides experimental evidence that the ϒ(3S) is significantly more suppressed than the ϒ(1S) at RHIC. The level of suppression for ϒ(1S) is comparable to that observed at the much higher collision energy at the Large Hadron Collider. These results point to the creation of a medium at RHIC whose temperature is sufficiently high to strongly suppress excited ϒ states.

Determining the gluonic gravitational form factors of the proton

The proton is one of the main building blocks of all visible matter in the Universe¹. Among its intrinsic properties are its electric charge, mass and spin². These properties emerge from the complex dynamics of its fundamental constituents-quarks and gluons-described by the theory of quantum chromodynamics^3-5. The electric charge and spin of protons, which are shared among the quarks, have been investigated previously using electron scattering². An example is the highly precise measurement of the electric charge radius of the proton⁶. By contrast, little is known about the inner mass density of the proton, which is dominated by the energy carried by gluons. Gluons are hard to access using electron scattering because they do not carry an electromagnetic charge. Here we investigated the gravitational density of gluons using a small colour dipole, through the threshold photoproduction of the J/ψ particle. We determined the gluonic gravitational form factors of the proton^7,8 from our measurement. We used a variety of models^9-11 and determined, in all cases, a mass radius that is notably smaller than the electric charge radius. In some, but not all cases, depending on the model, the determined radius agrees well with first-principle predictions from lattice quantum chromodynamics¹². This work paves the way for a deeper understanding of the salient role of gluons in providing gravitational mass to visible matter.

Beam Energy Dependence of Fifth- and Sixth-Order Net-Proton Number Fluctuations in Au+Au Collisions at RHIC

We report the beam energy and collision centrality dependence of fifth and sixth order cumulants (C_{5}, C_{6}) and factorial cumulants (κ_{5}, κ_{6}) of net-proton and proton number distributions, from center-of-mass energy (sqrt[s_{NN}]) 3 GeV to 200 GeV Au+Au collisions at RHIC. Cumulant ratios of net-proton (taken as proxy for net-baryon) distributions generally follow the hierarchy expected from QCD thermodynamics, except for the case of collisions at 3 GeV. The measured values of C_{6}/C_{2} for 0%-40% centrality collisions show progressively negative trend with decreasing energy, while it is positive for the lowest energy studied. These observed negative signs are consistent with QCD calculations (for baryon chemical potential, μ_{B}≤110  MeV) which contains the crossover transition range. In addition, for energies above 7.7 GeV, the measured proton κ_{n}, within uncertainties, does not support the two-component (Poisson+binomial) shape of proton number distributions that would be expected from a first-order phase transition. Taken in combination, the hyperorder proton number fluctuations suggest that the structure of QCD matter at high baryon density, μ_{B}∼750  MeV at sqrt[s_{NN}]=3  GeV is starkly different from those at vanishing μ_{B}∼24  MeV at sqrt[s_{NN}]=200  GeV and higher collision energies.

Evidence for Nonlinear Gluon Effects in QCD and Their Mass Number Dependence at STAR

The STAR Collaboration reports measurements of back-to-back azimuthal correlations of di-π^{0}s produced at forward pseudorapidities (2.6<η<4.0) in p+p, p+Al, and p+Au collisions at a center-of-mass energy of 200 GeV. We observe a clear suppression of the correlated yields of back-to-back π^{0} pairs in p+Al and p+Au collisions compared to the p+p data. The observed suppression of back-to-back pairs as a function of transverse momentum suggests nonlinear gluon dynamics arising at high parton densities. The larger suppression found in p+Au relative to p+Al collisions exhibits a dependence of the saturation scale Q_{s}^{2} on the mass number A. A linear scaling of the suppression with A^{1/3} is observed with a slope of -0.09±0.01.

Measurements of Proton High-Order Cumulants in sqrt[s_{NN}]=3 GeV Au+Au Collisions and Implications for the QCD Critical Point

We report cumulants of the proton multiplicity distribution from dedicated fixed-target Au+Au collisions at sqrt[s_{NN}]=3.0  GeV, measured by the STAR experiment in the kinematic acceptance of rapidity (y) and transverse momentum (p_{T}) within -0.5<y<0 and 0.4<p_{T}<2.0  GeV/c. In the most central 0%-5% collisions, a proton cumulant ratio is measured to be C_{4}/C_{2}=-0.85±0.09 (stat)±0.82 (syst), which is 2σ below the Poisson baseline with respect to both the statistical and systematic uncertainties. The hadronic transport UrQMD model reproduces our C_{4}/C_{2} in the measured acceptance. Compared to higher energy results and the transport model calculations, the suppression in C_{4}/C_{2} is consistent with fluctuations driven by baryon number conservation and indicates an energy regime dominated by hadronic interactions. These data imply that the QCD critical region, if created in heavy-ion collisions, could only exist at energies higher than 3 GeV.

Measurements of _{Λ}^{3}H and _{Λ}^{4}H Lifetimes and Yields in Au+Au Collisions in the High Baryon Density Region

We report precision measurements of hypernuclei _{Λ}^{3}H and _{Λ}^{4}H lifetimes obtained from Au+Au collisions at sqrt[s_{NN}]=3.0  GeV and 7.2 GeV collected by the STAR experiment at the Relativistic Heavy Ion Collider, and the first measurement of _{Λ}^{3}H and _{Λ}^{4}H midrapidity yields in Au+Au collisions at sqrt[s_{NN}]=3.0  GeV. _{Λ}^{3}H and _{Λ}^{4}H, being the two simplest bound states composed of hyperons and nucleons, are cornerstones in the field of hypernuclear physics. Their lifetimes are measured to be 221±15(stat)±19(syst)  ps for _{Λ}^{3}H and 218±6(stat)±13(syst)  ps for _{Λ}^{4}H. The p_{T}-integrated yields of _{Λ}^{3}H and _{Λ}^{4}H are presented in different centrality and rapidity intervals. It is observed that the shape of the rapidity distribution of _{Λ}^{4}H is different for 0%-10% and 10%-50% centrality collisions. Thermal model calculations, using the canonical ensemble for strangeness, describes the _{Λ}^{3}H yield well, while underestimating the _{Λ}^{4}H yield. Transport models, combining baryonic mean-field and coalescence (jam) or utilizing dynamical cluster formation via baryonic interactions (phqmd) for light nuclei and hypernuclei production, approximately describe the measured _{Λ}^{3}H and _{Λ}^{4}H yields. Our measurements provide means to precisely assess our understanding of the fundamental baryonic interactions with strange quarks, which can impact our understanding of more complicated systems involving hyperons, such as the interior of neutron stars or exotic hypernuclei.

Probing the Gluonic Structure of the Deuteron with J/ψ Photoproduction in d+Au Ultraperipheral Collisions

Understanding gluon density distributions and how they are modified in nuclei are among the most important goals in nuclear physics. In recent years, diffractive vector meson production measured in ultraperipheral collisions (UPCs) at heavy-ion colliders has provided a new tool for probing the gluon density. In this Letter, we report the first measurement of J/ψ photoproduction off the deuteron in UPCs at the center-of-mass energy sqrt[s_{NN}]=200  GeV in d+Au collisions. The differential cross section as a function of momentum transfer -t is measured. In addition, data with a neutron tagged in the deuteron-going zero-degree calorimeter is investigated for the first time, which is found to be consistent with the expectation of incoherent diffractive scattering at low momentum transfer. Theoretical predictions based on the color glass condensate saturation model and the leading twist approximation nuclear shadowing model are compared with the data quantitatively. A better agreement with the saturation model has been observed. With the current measurement, the results are found to be directly sensitive to the gluon density distribution of the deuteron and the deuteron breakup process, which provides insights into the nuclear gluonic structure.

Ruling out Color Transparency in Quasielastic ^{12}C(e,e^{'}p) up to Q^{2} of 14.2 (GeV/c)^{2}

Quasielastic ^{12}C(e,e^{'}p) scattering was measured at spacelike 4-momentum transfer squared Q^{2}=8, 9.4, 11.4, and 14.2  (GeV/c)^{2}, the highest ever achieved to date. Nuclear transparency for this reaction was extracted by comparing the measured yield to that expected from a plane-wave impulse approximation calculation without any final state interactions. The measured transparency was consistent with no Q^{2} dependence, up to proton momenta of 8.5  GeV/c, ruling out the quantum chromodynamics effect of color transparency at the measured Q^{2} scales in exclusive (e,e^{'}p) reactions. These results impose strict constraints on models of color transparency for protons.

Gamma Aminobutyric Acid Increases Absorption of Glycine-Bound Iron in Mice with Iron Deficiency Anemia

Iron deficiency is a leading cause of anemia. Amino acids are known to promote the absorption of both soluble and insoluble iron. The bioavailability of organic iron is higher than that of inorganic iron. Therefore, the aim of this study was to evaluate the iron absorption of glycine-bound iron (an organic iron) and a combination of glycine-bound iron and gamma aminobutyric acid (GABA) in mice with iron deficiency anemia (IDA). Mice were fed an iron-deficient diet for 3 weeks, followed by oral administration of GABA, inorganic iron, glycine-bound iron, or GABA plus glycine-bound iron for 5 weeks. Ferritin storage in the spleen was measure by immunohistochemistry (IHC). Iron deposition in the liver and spleen tissues was analyzed using atomic absorption spectrometry. Expression levels of iron absorption-related genes were measured by quantitative real-time polymerase chain reaction (qPCR). Iron absorption was enhanced in the glycine-bound iron-treated group compared with the inorganic iron-treated group. Hemoglobin, serum Fe, ferritin, and liver iron levels did not increase in mice treated with GABA alone. However, mice administered GABA in combination with glycine-bound iron showed higher iron absorption than those administered organic iron alone. Our results indicate that glycine-bound iron in combination with GABA might exert a synergistic effect on iron absorption and bioavailability, suggesting that the addition of GABA to existing iron supplements might increase their effectiveness for treating IDA.

Enzyme-Treated Zizania latifolia Ethanol Extract Protects from UVA Irradiation-Induced Wrinkle Formation via Inhibition of Lysosome Exocytosis and Reactive Oxygen Species Generation

Ultraviolet A (UVA) is a risk factor for photoaging and wrinkle formation. Zizania latifolia is an herbaceous perennial plant. It contains many bioactive compounds such as tricin that show antioxidative and anti-inflammatory effects. The aim of this study was to investigate the antiwrinkle effect of a mixture of hydrolytic enzyme (cellulase, hemicellulase and pectinase)-treated Z. latifolia extract (ZLE) and tricin on UVA-irradiated human dermal fibroblasts (HDFs) and SKH-1 hairless mice. Treatment of UVA-irradiated HDF cells with ZLE and tricin significantly decreased UVA induced-plasma membrane rupture, generation of ROS, expression levels of total and secreted lysosomal associated membrane protein (LAMP-1), cathepsin B and metalloproteinases (MMPs) and inhibited NF-κB activation. In the animal study, UVA-damaged epidermal and dermal tissues were repaired by the ZLE and tricin treatments. Administration of ZLE or tricin to UVA-irradiated animals recovered skin surface moisture and collagen fiber in dermal tissue. Treatment of ZLE or tricin decreased wrinkle formation, secretion of MMPs and expression levels of vascular endothelial growth factor (VEGF) and cathepsin B, and increased the expression level of collagen-1 in UVA-irradiated animals. Overall, the ZLE and tricin treatments decreased the skin damage induced by UVA irradiation via inhibition of lysosomal exocytosis and ROS generation. Therefore, ZLE and tricin are promising as antiwrinkle and antiphotoaging agents.

Pregnancy and patients with preexisting lupus nephritis: 15 years of experience at a single center in Korea

We investigated obstetric outcomes and comorbidities during pregnancy in females with preexisting lupus nephritis (LN) and identified predictors for renal flare. In cases of renal flare during pregnancy, we assessed the long-term post-delivery renal outcome. We performed a retrospective analysis of 183 systemic lupus erythematosus (SLE) pregnancies including blood chemistry, urinalysis, urinary protein, and disease activity recorded at prepregnancy, during pregnancy, and at one month, six months, and one year post-delivery. Pregnancies with preexisting LN had a greater frequency of adverse obstetric outcomes and maternal comorbidity. Renal flares occurred in 50.7% of pregnancies with preexisting LN, 89.2% of which were reactivations. Renal flare among pregnancies with SLE was predicted based on preexisting lupus nephritis (OR 17.73; 95% CI, 5.770–54.484), an active disease prior to pregnancy (OR 2.743; 95% CI, 1.074–7.004), and prepregnancy eGFR < 90 ml/min/1.73 m2 (OR 11.151; 95% CI, 3.292–37.768).

Persistent LN one year after delivery was observed in 33.3% of pregnancies. The median follow-up time after delivery was 5.9 (3.1–9.7) years and chronic kidney disease (CKD) occurred in 21.4% of pregnancies with renal flare. In patients with renal flare, failing to achieve a ≥ 50% reduction in urine protein levels within six months, longer total duration of renal flare, and acute kidney injury at renal flare was associated with CKD development. Females with preexisting LN should achieve remission before pregnancy. When patients experience renal flares during pregnancy, it is important to reduce the proteinuria level by >50% within six months and to achieve early remission for excellent long-term renal outcomes.

Hydroxychloroquine and pregnancy on lupus flares in Korean patients with systemic lupus erythematosus

We investigated the clinical and laboratory characteristics of pregnancies with systemic lupus erythematosus (SLE) and identified lupus flare predictors during pregnancy. Additionally, we examined lupus activity and pregnancy outcomes in SLE patients who continued, discontinued or underwent no hydroxychloroquine (HCQ) treatment during pregnancy. We retrospectively analyzed 179 pregnancies in 128 SLE patients at Seoul St. Mary’s Hospital, Korea, between 1998 and 2012 and then assessed the clinical profiles and maternal and fetal outcomes. Overall, 90.5% of pregnancies resulted in a successful delivery and were divided into two groups: those who experienced lupus flares (80 pregnancies, 44.7%) and those who did not (99 pregnancies, 55.3%). Increased preeclampsia, preterm births, low birth weight, intrauterine growth restriction (IUGR), and low 1-minute Apgar scores occurred in pregnancies with lupus flares compared to pregnancies in quiescent disease. Lupus flares were predicted by HCQ discontinuation, a history of lupus nephritis, high pre-pregnancy serum uric acid and low C4 levels. Our study indicates that achieving pre-pregnancy remission and continuing HCQ treatment during pregnancy are important for preventing lupus flares.

Electron tunneling in carbon nanotube composites

Nanocomposites, such as polymer blending with carbon nanotubes (CNTs), have been shown to have a drastic reduction in the resistivity and become conductive when the CNTs concentration has reached a certain percolation threshold. The reduction could be more than a millionth of the original polymer material. This has been realized as the formation of an infinite cluster of connected CNTs or pathways. Therefore, the conductivity of a nanocomposite should follow that of CNTs. Here we show that the resistivity of a nanocomposite is not governed by the interconnected CNTs, but the polymer between neighboring CNTs. That is, polymer-CNTs exhibit the nature of a conducting polymer, which can be explained as the tunneling of electrons one by one from the first CNT electrode to the next-nearest CNT electrode, forming a CNT/polymer pathway. A conduction model based on the tunneling of electrons passing, one by one, through the polymer gap between two neighboring CNT electrodes is formulated and derived. This model can accurately predict the significant reduction of the polymer-CNTs' resistivity with the addition of CNTs. The temperature effect can be readily incorporated to account for resistivity variation with the temperature of this nanocomposites.

Piezoresistive characteristics of MWNT nanocomposites and fabrication as a polymer pressure sensor

Polyimide (PI)-carbon nanotube composites were fabricated by in situ polymerization using multi-wall carbon nanotubes (MWNT) as fillers. The composite film was characterized by some analytical instruments to ensure its structure and good dispersion of the MWNTs in the composites. The electrical resistivity of this composite was found to vary significantly with both the temperature and the stress in the material. The PI-MWNT composites possess a very linear piezoresistive nature which can be used as a good pressure sensor material, provided with proper temperature compensation. Fabrication of a micropolymer pressure sensor using this nanocomposite sensing material is demonstrated and sensor performance is evaluated. The sensor has a higher sensitivity than a polysilicon sensor, rapid response, and is thermally stable. The sensor is suitable for mass production, and can be widely applied or integrated in a microfluidic system or biochip where pressure information is required.

Investigation of the association between 677C>T and 1298A>C 5,10-methylenetetra- hydrofolate reductase gene polymorphisms and normal-tension glaucoma

PURPOSE

Homozygous polymorphism of the 5,10-methylenetetrahydrofolate reductase (MTHFR) gene and resultant hyperhomocysteinaemia have been established as an independent risk factor for vascular diseases. There are evidences that vascular abnormalities are involved in the pathogenesis and progression of normal-tension glaucoma (NTG). In the present study, we were to find out the associations between 677C>T and 1298A>C polymorphisms of the MTHFR gene and NTG.

METHODS

This was a retrospective, case-controlled study enrolling 78 NTG patients and 100 controls. DNA from peripheral blood lymphocytes was extracted and the genotypes of polymorphisms (677C>T and 1298A>C) in the MTHFR gene were determined using PCR followed by restriction enzyme digestion. The frequencies of the polymorphic genotypes in the patients with NTG and controls were compared.

RESULTS

The frequencies of the polymorphisms of the MTHFR gene (677C>T and 1298A>C) in the NTG patients were not significantly different from those of controls. But the younger NTG patients (age at diagnosis < or = 45 years) showed significantly higher prevalence of 677C>T polymorphism than the older NTG patients (age at diagnosis > 45 years) (TT genotype, 38.9 vs 11.9%, P=0.006, OR=4.71, 95% CI=1.49-14.9) and than the younger control subgroup (TT genotype, 38.9 vs 6.1%, P=0.001, OR=9.86, 95% CI=2.23-42.4).

CONCLUSIONS

The 677C>T polymorphism was significantly associated with NTG in the younger patients, while 1298A>C polymorphism was not. This suggests that 677C>T polymorphism of the MTHFR gene can be a genetic risk factor of NTG in Korean population.

Negative Endoskopie sowie Mehrzeilendetektor-CT bei Patienten mit akuter unterer Gastrointestinalblutung

PURPOSE

To evaluate the clinical use of (99m)Tc red blood cell imaging (RBC imaging) in patients presenting with acute lower gastrointestinal (GI) bleeding and negative endoscopy and multislice computed tomography (MSCT) findings.

PATIENTS AND METHODS

In 31 consecutive patients with acute lower GI bleeding in whom the endoscopy findings were negative or the procedure was not feasible, dual-phase MSCT of the abdomen was performed [collimation 4x1 mm (arterial phase), 4x2.5 mm (venous phase)]. MSCT was followed by a (99m)Tc red blood cell scan in patients in whom no active bleeding was visible by CT. Images were created within 24 h after administration of the tracer, depending on the clinical symptoms. The results of the imaging modalities were correlated with clinical course and surgical treatment.

RESULTS

In 20 of 31 patients MSCT showed no active bleeding and a (99m)Tc red blood cell scan was performed. In 8 of 20 patients RBC imaging was also negative. Of these eight patients five were stable and did not require further diagnostic work-up; in the other three bleeding persisted and these patients required surgical treatment. In 12 of 20 patients active bleeding was demonstrated using a (99m)Tc red blood cell scan. Of 12 patients with positive RBC scintigraphy findings, 8 underwent surgery, where the site of bleeding was confirmed.

CONCLUSION

In patients with acute lower GI bleeding with negative or nondiagnostic endoscopy or MSCT findings, (99m)Tc red blood cell imaging is a useful tool in an emergency algorithm, improving the overall bleeding detection rate.

Mitochondrial DNA content is decreased in autosomal dominant optic atrophy

BACKGROUND

Autosomal dominant optic atrophy (ADOA) is the commonest form of inherited optic neuropathy. Mutations in the OPA1 gene encoding a dynamin-related mitochondrial protein underlie ADOA and may perturb the biogenesis and maintenance of mitochondria.

OBJECTIVE

To investigate the mutation spectrum of the OPA1 gene and assess alterations in mitochondrial content caused by OPA1 mutations.

METHODS

Sixteen Korean patients with clinically suspected ADOA were studied. The mutation spectrum of the OPA1 gene was analyzed by PCR single-strand conformation polymorphism and sequencing, and mitochondrial DNA (mtDNA) content was quantified by real-time PCR.

RESULTS

Eight different mutations were found, including five novel mutations. Quantitative real-time PCR analysis showed excellent linearity and precision for the determination of mtDNA copy numbers. The number of mtDNA copies per cell in patients with OPA1 gene mutations (ages 7 to 40) was significantly lower than those in all normal control subjects (p = 0.037), particularly lower than in normal control subjects ages 10 to 39 (p = 0.022).

CONCLUSION

The mutation spectrum of the OPA1 gene disclosed marked genetic heterogeneity and the mitochondrial DNA content was found to be lower in autosomal dominant optic neuropathy, which provides direct evidence for a pathogenetic role of mutations of the OPA1 gene.

[Localization of bleeding using 4-row detector-CT in patients with clinical signs of acute gastrointestinal hemorrhage]

PURPOSE

There is no gold-standard regarding the diagnostic work-up and therapy of an acute gastrointestinal (GI) hemorrhage. In most cases endoscopy provides the diagnosis but in a low percentage this modality is not feasible or negative. Purpose of this study was to evaluate the role of multi-phase Multi-Slice-Computertomography (MSCT) as a modality to diagnose and locate the site of acute GI hemorrhage in case of unfeasible or technically difficult endoscopy.

MATERIALS AND METHODS

58 patients, presenting with clinical signs of lower GI hemorrhage, were examined through a 24-month period. Preliminary endoscopy was either negative or unfeasible. Images were obtained with a four-detector row CT with an arterial (4 x 1 mm collimation, 0.8 mm increment, 1.25 mm slice width, 120 kV, 165 mAs) and portal venous series (4 x 2,5 mm collimation, 2 mm increment, 3 mm slice width, 120 kV, 165 mAs). Time interval between endoscopy and CT varied between 30 minutes and 3 hours. The results of the MSCT were correlated with clinical course and surgical or endoscopical treatment.

RESULTS

20 of the 58 patients (34 %) undergoing MSCT had a bleeding site identified, thus providing decisive information for the following intervention. In case of a following therapeutic intervention there was 100 % correlation regarding the bleeding site. In 38 of the 58 patients (66 %), a bleeding site was not identified by MSCT. Twenty of these 38 patients (53 %) were stable and required no further treatment. In 18 of these 38 patients further interventional therapy was required due to continuing hemorrhage and in all of those patients the bleeding site was detected by intervention.

CONCLUSION

Compared to other diagnostic methods MSCT is a fast, widely-available and low-risk technique for the localization of active GI hemorrhage. The clinical use seems to be justified since in more than one third of the patients, MSCT demonstrates the site of bleeding and provides decisive information for further interventional therapy. Concerning those patients, in whom MSCT is negative (38 out of 58 patients), only every second patient requires any additional diagnostic work-up.

[MRI-morphology and staging of congenital mesoblastic nephroma: evaluation of a collection with 20 patients]

PURPOSE

To differentiate classic and cellular type of congenital mesoblastic nephroma (CMN) in MRI and to evaluate MRI for staging according to the Societe Internationale de Oncologie Pediatrique (SIOP).

MATERIAL AND METHODS

MRI examinations of 20 children with CMN (age 1st to 16th months, classic type n = 11, cellular type n = 7, mixed type n = 2) were analyzed retrospectively. Cysts, necrosis, hemmorhage in the tumor, signal intensity, tumor structure, thrombosis and dilatation of renal vein, crossing of the body midline, peripheral contrast-enhancement, tumor volume and existence of a tumor pseudocapsule in contrast to the residual kidney were described. The radiologic stage was compared with the histopathologic stage (infiltration of perirenal fat and infiltration of the renal sinus).

RESULTS

Tumors of the classic type (mean volume 67.9 ml) had necrosis in 1 case, crossed the midline in 1 case, had no cysts or bleeding, and had a peripheral contrast-enhancement in 1 case, and were heterogeneous in 9 cases. The cellular type (mean volume 302.8 ml) had tumor necrosis in 6 cases, bleeding in 3 cases, cysts in 3 cases, crossed the midline in 4 cases, and peripheral contrast enhancement in 2 cases, and was predominantly heterogeneous. Mixed tumor types (7 ml and 202 ml) had tumor necrosis in 1 case and crossed the midline in 1 case, a peripheral contrast enhancement in 2 cases and a homogenous structure in 1 case. The signal intensity in T1 w and T2 w images was not specific. The renal vein was inconspicuous in all children. The evaluation of the infiltration in perirenal fatty tissue was true positive in 1 case, true negative in 10 cases, false negative in 4 cases and false positive in 5 cases. The infiltration of the renal hilus was true positive in 10 children, false positive in 8 cases and true negative in 2 cases.

CONCLUSION

A typical finding of CMN in MRI is a heterogeneous tumor without demarcation from the rest of the kidney parenchyma by a pseudocapsule. The cellular type of CMN tends to have a higher tumor volume and shows more necrosis, bleeding and cysts than the classic type in MRI. A peripheral contrast-enhancement in MRI is not characteristic for any type of CMN. Local tumor staging is not possible with MRI.

Portal vein erosion and acute abdominal hemorrhage as a complication of acute pancreatitis

The case of a 35-year-old male with portal vein erosion and acute life-threatening abdominal hemorrhage as a complication of acute pancreatitis is reported. Erosion of arterial walls is the most common complication of pancreatitis and pancreatic pseudocysts, and erosion of the portal vein leading to a fistula between the pancreas and the portal vein is very rare. Diagnosis was made by multislice spiral computed tomography, and nonsurgical treatment was elected, leading to complete recoverage.

Head-column field-amplified sample stacking in capillary electrophoresis for the determination of cimetidine, famotidine, nizatidine, and ranitidine-HCl in plasma

In this study, low concentrations of histamine2-receptor (H2-)antagonists were effected across a water plug, with separation taking place in a binary buffer comprising ethylene glycol and NaH2PO4 (pH 5.0), and detection at 214 nm. Liquid-liquid extraction with ethyl acetate- isopropanol is shown to provide extracts that are sufficiently clean. The calibration curves were linear over a concentration range of 0.1-2.00 microg/mL cimetidine, 0.2-5.0 microg/mL ranitidine-HCl, 0.3-5.0 microg/mL nizatidine, and 0.1-3.0 microg/mL famotidine. Mean recoveries were > 82%, while the intra- and interday relative standard deviations (RSDs) and relative errors (REs) were all < 13%. The method is sensitive with a detection limit of 3 ng/mL cimetidine, 30 ng/mL ranitidine HCl, 50 ng/mL nizatidine and 10 ng/mL famotidine (S/N = 3, electric-driven injection 90 s). This newly developed capillary electrophoresis (CE) method was applied for the determination of analytes extracted from plasma taken from a volunteer dosing a cimetidine, ranitidine, and nizatidine tablet simultaneously. These three H2-antagonists can be detected in real samples by this method, excluding the low dosing of famotidine tablet.

Simultaneous determination of cimetidine, famotidine, nizatidine, and ranitidine in tablets by capillary zone electrophoresis

A simple capillary zone electrophoresis (CZE) method is described for the simultaneous determination of cimetidine (CIM), famotidine (FAM), nizatidine (NIZ), and ranitidine (RAN). The analysis of these drugs was performed in a 100 mM phosphate buffer, pH 3.5. Several parameters were studied, including wavelength for detection, concentration and pH of phosphate buffer, and separation voltage. The quantitative ranges were 100-1,000 microM for each analyte. The intra- and interday relative standard deviations (n = 5) were all less than 4%. The detection limits were found to be about 10 microM for CIM, 20 microM for RAN, 20 microM for NIZ, and 10 microM for FAM (S/N = 3, injection 1 s) at 214 nm. All recoveries were greater than 92%. Applications of the method to the assay of these drugs in tablets proved to be feasible.

Hypoxia decreases proteins involved in epithelial electrolyte transport in A549 cells and rat lung

Fluid reabsorption from alveolar space is driven by active Na reabsorption via epithelial Na channels (ENaCs) and Na-K-ATPase. Both are inhibited by hypoxia. Here we tested whether hypoxia decreases Na transport by decreasing the number of copies of transporters in alveolar epithelial cells and in lungs of hypoxic rats. Membrane fractions were prepared from A549 cells exposed to hypoxia (3% O(2)) as well as from whole lung tissue and alveolar type II cells from rats exposed to hypoxia. Transport proteins were measured by Western blot analysis. In A549 cells, alpha(1)- and beta(1)-Na-K-ATPase, Na/K/2Cl cotransport, and ENaC proteins decreased during hypoxia. In whole lung tissue, alpha(1)-Na-K-ATPase and Na/K/2Cl cotransport decreased. alpha- and beta-ENaC mRNAs also decreased in hypoxic lungs. Similar results were seen in alveolar type II cells from hypoxic rats. These results indicate a slow decrease in the amount of Na-transporting proteins in alveolar epithelial cells during exposure to hypoxia that also occurs in vivo in lungs from hypoxic animals. The reduced number of transporters might account for the decreased transport activity and impaired edema clearance in hypoxic lungs.

Total hip reconstruction in the anatomically distorted hip. Cemented versus hybrid total hip arthroplasty

Recent reports in the literature strongly support the idea that cement is the optimum form of fixation of the femoral component in total hip replacement. For hybrid total hip arthroplasty, we used a cemented cup instead of an uncemented cup since this was inevitable in cases of poorly developed acetabulum. The uncemented cone femoral component is also beneficial in cases of extremely narrow and cylindrical configuration of the medullary cavity of untreated congenital dislocation of the hips (CDH) and tuberculosis or septic arthritis in childhood. We reviewed the clinical result of a consecutive series of patients with cemented total hip arthroplasty (THA) compared with recent studies on hybrid reconstruction using survivorship analysis. This subsequent study involved a hybrid uncemented Wagner cone femoral component and a cemented acetabular component with roof reinforcement by additional impacted cancellous allograft with hydroxyapatite (HA). We believe that early failure of the cemented components was due to an adverse effect of thin cement mantles around cemented femoral stems as well as the cemented cup in THA. In addition, 8 patients who received our modification of the Charnley CDH component had poor results even though we reduced the stem geometry and thickness. Furthermore, intraoperative fracture and splitting of the proximal femur was a major complication during implantation. Contrary to expectations, the results of these hybrid reconstructions were extremely encouraging (average follow-up period of 2-4.5 years). In addition to our experience of the cemented versus hybrid THA involving the uncemented Wagner femoral component, we have determined positive indications for the untreated and severely distorted anatomy of bilateral CDH for which surgical interventions for reconstruction were not recommended before.

Tomographic identification of gas bubbles in two-phase flows with the combined use of the algebraic reconstruction technique and the genetic algorithm

Combined use of the algebraic reconstruction technique (ART) and the genetic algorithm (GA) shows highly accurate and efficient tomographic reconstruction of line-of-sight projection images of two-phase flows compared with reconstructions obtained by separate use of these methods. A modified GA-based tomography uses the ART reconstruction result as preliminary information on the number, shapes, and sizes of bubbles to be reconstructed. This combined use of the two methods exploits faster convergence of the ART to the approximate solution space and more robust and accurate optimization of the GA to the ultimate solution space. In the investigation a computer-synthesized phantom field that consisted of five elliptical gas bubbles in liquid or solid surroundings was used.

A Rapid and Sensitive Cellular Enzyme-Linked Immunoabsorbent Assay (CELISA) for the Detection and Quantitation of Antibodies against Cell Surface Determinants II. Optimal Reagent Concentrations and Predictive Analysis

A cellular enzyme-linked immunosorbent assay (CELISA) was developed for the detection and quantification of antibodies elicited against allogeneic cell surface determinants. The technique uses a solid-phase cell matrix created by fixing cells with a mild formalin solution onto the bottom of a 96-well microtiter plate. A primary layer of alloantisera is first reacted against rat target cells. The secondary antibody, peroxidase conjugated antirat IgG, is then added to each well and serves as the second sandwich layer. Optimal reagent concentrations were determined by serial dilution analysis of various cell concentrations and secondary antibody dilutions. It was found that 200,000 cells per well was the optimal target cell concentration. However, 100,000 cells per well was also sufficient to run the assay with acceptable performance characteristics. Even lower cell concentrations of 10,000 and 20,000 cells/well, although not optimal, also produced acceptable results. Secondary antibody concentration with respect to the optimal cell concentration was determined to be 1:500. At 200,000 cells per well and a 1:500 secondary antibody dilution, the assay presented excellent coefficients of determination and high positive to negative ratios. The reaction was found to be very sensitive in yielding high antibody titers with low background levels and could be defined mathematically as a linear-log function. Titers of multiple unknown alloantibody samples were easily and accurately predicted in an automated manner by regression analysis form known standards. This immunoassay will be useful in studies of cell surface determinant expression and quantitation of antibodies reactive to such markers.

Fluoride levels in whole saliva of preschool children after brushing with 0.25 g (pea-sized) as compared to 1.0 g (full-brush) of a fluoride dentifrice

Concerns regarding an increased risk of dental fluorosis related to ingesting fluoride-containing toothpastes by preschool children have led to recommendations to reduce the amount of toothpaste used for young children to a pea-sized amount. The purpose of this study was to determine the effect on salivary fluoride levels of reducing the amount of toothpaste used in a preschool-age (4-5 years) population. Salivary fluoride concentrations were determined for 10 children whose teeth were brushed with both 0.25 g and 1.0 g of a fluoridated toothpaste on two separate days. Initial salivary fluoride levels following the use of 0.25 g of toothpaste were less than half of the salivary fluoride concentrations when 1.0 g of toothpaste was used, and levels returned to baseline more rapidly. The reduced salivary fluoride levels when less toothpaste is used may result in a reduced efficacy for caries prevention. However, any potential reduction in caries prevention may still be outweighed by the risk of increased fluoride ingestion with larger amounts of toothpaste in preschool children. The results of this study suggest that a reduction in the amount of a fluoridated toothpaste to a pea-sized amount be limited only to young children who are at risk of ingesting toothpaste.

A rapid and sensitive cellular enzyme-linked immunoabsorbent assay (CELISA) for the detection and quantitation of antibodies against cell surface determinants. I. A comparison of cell fixation and storage techniques

A solid phase cellular ELISA was designed and evaluated for the detection of antibodies specific for cell surface determinants. It was hypothesized that certain fixation and freezing procedures would result in stabilization of cell structures for prevention of antigen diffusion and extraction during washing procedures. This would assure assay accuracy and convenient sample management. It was hypothesized that fixation with certain reagents prior to analysis would not alter antigenicity of antibody targeted epitopes. In order to improve the preservation of the cells following cell binding to the solid phase matrix while still retaining antigenicity and morphology, a series of fixatives and storage procedures were screened to determine which were best suited for CELISA. Methanol, washing buffer (WB), Hanks' balanced salt solution (HBSS), and 0.5% formalin in HBSS were examined by comparing their relative cell binding capacity and the subsequent cell morphology. In consideration of all variables, fixation in 0.5% formalin provided the best maintenance of cell antigenicity, morphology, binding, and was associated with consistent results. Cells used immediately after fixation and fixed cells used after storage at -80 degrees C for up to 12 months were compared to determine if long term storage affected antigenicity. Since frozen cells and fresh cells demonstrated statistically identical positive to negative ratios and consistency of antibody binding, it was determined that long term frozen storage of formalin-fixed cells did not adversely affect antibody binding capacity to cell surface determinants.

Induction of the POU domain transcription factor Oct-2 during T-cell activation by cognate antigen

Oct-2 is a transcription factor that binds specifically to octamer DNA motifs in the promoters of immunoglobulin and interleukin-2 genes. All tumor cell lines from the B-cell lineage and a few from the T-cell lineage express Oct-2. To address the role of Oct-2 in the T-cell lineage, we studied the expression of Oct-2 mRNA and protein in nontransformed human and mouse T cells. Oct-2 was found in CD4+ and CD8+ T cells prepared from human peripheral blood and in mouse lymph node T cells. In a T-cell clone specific for pigeon cytochrome c in the context of I-Ek, Oct-2 was induced by antigen stimulation, with the increase in Oct-2 protein seen first at 3 h after activation and continuing for at least 24 h. Oct-2 mRNA induction during antigen-driven T-cell activation was blocked by cyclosporin A, as well as by protein synthesis inhibitors. These results suggest that Oct-2 participates in transcriptional regulation during T-cell activation. The relatively delayed kinetics of Oct-2 induction suggests that Oct-2 mediates the changes in gene expression which occur many hours or days following antigen stimulation of T lymphocytes.

Mechanism of bcl-2 activation in human follicular lymphoma

The t(14; 18) chromosomal translocation of human follicular lymphoma recombines the bcl-2 gene from chromosome 18 with the immunoglobulin heavy chain joining region. In the t(14; 18) translocation bearing cell line SU-DHL-6, this results not only in an inappropriately high rate of bcl-2 transcription for a mature B cell, but also in two potentially critical point mutations. To determine the relative importance of these mutations, we searched for their presence in DNA from the involved lymph nodes of 12 patients with t(14; 18) follicular lymphoma. bcl-2 genomic sequences were specifically amplified by the polymerase chain reaction technique and then directly sequenced. None of the 12 samples analysed revealed the codon 7 or codon 129 mutation detected in SU-DHL-6. We conclude that abnormal expression of bcl-2 rather than structural alterations at codon 7 or 129 play an important role in the disordered growth and differentiation of follicular B-cell lymphoma.

A human protein specific for the immunoglobulin octamer DNA motif contains a functional homeobox domain

The homeobox domain is shared by Drosophila homeotic proteins, yeast mating type proteins, and some functionally uncharacterized mammalian proteins. A lymphoid-restricted human protein that binds to the immunoglobulin octamer regulatory motif was shown to contain an amino acid sequence that has 33% amino acid identity with the consensus sequence of the previously cloned homebox domains. This homeobox gene was localized to chromosome 19, thus mapping separately from other human homebox genes. A mutant protein containing amino acid substitutions within a putative helix-turn-helix motif in the homeobox domain did not bind DNA detectably. This human homeobox protein was shown to bind the same DNA sequence as the homeobox domains of the yeast mating type proteins and Drosophila homeotic protein, suggesting that homeobox proteins may have closely related DNA binding characteristics.

Consequences of the t(14;18) chromosomal translocation in follicular lymphoma: deregulated expression of a chimeric and mutated BCL-2 gene

The t(14;18) chromosomal translocation of human follicular lymphoma recombines the candidate transforming gene bcl-2, located at 18q21, with the immunoglobulin (Ig) H-chain joining region (JH) at 14q32. To elucidate the consequences of this translocation, we cloned bcl-2 cDNAs from a pre-B cell line (Nall-1) and a t(14;18) lymphoma cell line (SU-DHL-6) and compared these sequences with their genomic counterparts. These studies revealed the complexity of bcl-2 gene expression in which six potential polyadenylation signals in exon 3 and two different 5' exons (exons 1 and 2) and promoters are alternatively used to generate different sized bcl-2 mRNAs. A single open reading frame (ORF), at the junction of exons 2 and 3, predicts a 239 amino acid, 26 kD protein. Most chromosome 18 breakpoints cluster within a 150 bp region of exon 3. In SU-DHL-6 the t(14;18) translocation juxtaposes a truncated bcl-2 gene with J6 in a tail-to-head configuration, resulting in the deregulated expression of chimeric bcl-2/Ig transcripts. Importantly, the SU-DHL-6 bcl-2 cDNA also contained several point mutations in the ORF, two of which altered the primary amino acid sequence. The deregulated expression of an altered bcl-2 gene may play a critical role in the disordered growth and differentiation of follicular B cell lymphoma.

IgG and IgE antibody response following Pollinex-R immunotherapy

Specific antibodies to ragweed pollen antigens were studied in 22 patients given preseason Pollinex-R (glutaraldehyde-modified ragweed tyrosine-adsorbate) (PR), 17 without immunotherapy, and 8 on maintenance doses of aqueous ragweed extracts. The PR-group showed about fourfold increases in IgG antibodies in season when compared with pretreatment levels (P less than .001). IgG antibody changes from before season to season in other groups and IgE antibody changes in all three groups were not significant. Despite this, IgG antibodies in season had fallen from their peak achieved with PR. About one-third of PR-treated patients still manifested significant symptomatology irrespective of changes in IgG antibodies. We thus conclude that although changes in specific IgG may be an important correlate in PR-immunotherapy, additional mechanisms for clinical responsiveness remain to be clarified.

Serum thymosin-alpha 1: lack of association between elevated levels and HIV infection

Serum thymosin-alpha 1 levels as detected by radioimmunoassay (RIA) have been reported to be elevated in AIDS. We studied 143 individuals in two risk groups for AIDS (male homosexuals and haemophiliacs) for serum thymosin-alpha 1 and antibodies to HIV. RIA for thymosin-alpha 1 was performed in Dr A. Goldstein's laboratory at George Washington University, Washington DC. We found that similar proportions of seropositive and seronegative subjects within each risk group showed elevated thymosin-alpha 1 levels. Retesting after 6 months did not reveal significant increments over previous levels in seropositive subjects or in those developing HIV antibodies in the repeat samples. Thus, although elevated thymosin-alpha 1 levels might be a possible serum marker for AIDS, their association with HIV infection was not demonstrated. In addition, the male homosexuals we studied showed significantly lower thymosin-alpha 1 levels than haemophiliacs but this difference remains to be explained.

Evidence for a defect in "switch" T cells in patients with immunodeficiency and hyperimmunoglobulinemia M

Immunodeficiency with hyperimmunoglobulinemia M is a syndrome characterized by normal to elevated serum levels of IgM and low levels or absence of IgG and IgA. The defect in this syndrome is thought to reside within the B lymphocyte, which may be unable to undergo a "switch" in immunoglobulin class from IgM to IgG or IgA. To address this question more directly, we cultured B cells from nine patients with this syndrome with pokeweed mitogen and either "switch" T cells or normal control T cells. In cultures with normal T cells, only IgM was secreted, whereas in cultures with switch T cells, IgG as well as IgM, or IgM, IgG, and IgA were secreted. Furthermore, analysis of the immunoglobulin heavy-chain genes in these B cells by means of genetic probes of constant and switch regions revealed normal gene patterns. These data suggest that B cells from patients with hyperimmunoglobulinemia M may not be abnormal, as previously proposed, and that, at least in some patients with this syndrome, a defect in switch T cells may be pathogenic.

Responsiveness of human T-lymphocyte subpopulations in autologous mixed-lymphocyte reaction using xenoprotein-free separated cells: autologous reactivity lies chiefly in a low density T-cell fraction

The responsiveness in the autologous mixed-lymphocyte reaction (AMLR) by human T cells separated using two different methods not involving xenoantigen contract was examined. Although T cells from nylon-wool columns were active in AMLR, T cells separated by a Percoll gradient method responded poorly. Further separation of T cells from nylon-wool columns into low density (TL) and high density (TH) fractions by Percoll revealed that TL was enriched, while TH was depleted, in AMLR responsiveness. This difference could not be accounted for by differences in the helper or suppressor cells in the fractions. Moreover, TH responded well in secondary AMLR. Therefore the T cells reactive in AMLR reside chiefly, although not exclusively, in the low density fraction.

Dissociation of stimulatory capacity in mixed lymphocyte reaction and proliferative responses to pokeweed mitogen among peripheral blood non-T cells

The stimulatory capacity in mixed lymphocyte reaction (MLR) and responsiveness to pokeweed mitogen (PWM) by peripheral blood non-T cells were studied. E rosette- and adherent cell-depleted lymphocytes were divided into low, medium and high density populations using discontinuous Percoll gradient. Low density non-T cells were potent stimulators in both autologous and allogeneic MLR despite low proliferative response to PWM. In contrast, those with medium density showed weaker stimulation in autologous though not in allogeneic reactions and underwent strong blastogenesis in PWM cultures. Non-T cells with high density had low MLR-stimulatory capacity and yet manifested the highest stimulation indices on PWM stimulation. These findings suggest that functional characteristics of non-T cells may be separable on the basis of cell density.