Determination of Spin-Parity Quantum Numbers of X(2370) as 0^{-+} from J/ψ→γK_{S}^{0}K_{S}^{0}η^{'}

Based on (10087±44)×10^{6}  J/ψ events collected with the BESIII detector, a partial wave analysis of the decay J/ψ→γK_{S}^{0}K_{S}^{0}η^{'} is performed. The mass and width of the X(2370) are measured to be 2395±11(stat)_{-94}^{+26}(syst)  MeV/c^{2} and 188_{-17}^{+18}(stat)_{-33}^{+124}(syst)  MeV, respectively. The corresponding product branching fraction is B[J/ψ→γX(2370)]×B[X(2370)→f_{0}(980)η^{'}]×B[f_{0}(980)→K_{S}^{0}K_{S}^{0}]=(1.31±0.22(stat)_{-0.84}^{+2.85}(syst))×10^{-5}. The statistical significance of the X(2370) is greater than 11.7σ and the spin parity is determined to be 0^{-+} for the first time. The measured mass and spin parity of the X(2370) are consistent with the predictions of the lightest pseudoscalar glueball.

Observation of Structures in the Processes e^{+}e^{-}→ωχ_{c1} and ωχ_{c2}

We present measurements of the Born cross sections for the processes e^{+}e^{-}→ωχ_{c1} and ωχ_{c2} at center-of-mass energies sqrt[s] from 4.308 to 4.951 GeV. The measurements are performed with data samples corresponding to an integrated luminosity of 11.0  fb^{-1} collected with the BESIII detector operating at the Beijing Electron Positron Collider storage ring. Assuming the e^{+}e^{-}→ωχ_{c2} signals come from a single resonance, the mass and width are determined to be M=(4413.6±9.0±0.8)  MeV/c^{2} and Γ=(110.5±15.0±2.9)  MeV, respectively, which is consistent with the parameters of the well-established resonance ψ(4415). In addition, we also use one single resonance to describe the e^{+}e^{-}→ωχ_{c1} line shape and determine the mass and width to be M=(4544.2±18.7±1.7)  MeV/c^{2} and Γ=(116.1±33.5±1.7)  MeV, respectively. The structure of this line shape, observed for the first time, requires further understanding.

Observation of D^{+}→K_{S}^{0}a_{0}(980)^{+} in the Amplitude Analysis of D^{+}→K_{S}^{0}π^{+}η

We perform for the first time an amplitude analysis of the decay D^{+}→K_{S}^{0}π^{+}η and report the observation of the decay D^{+}→K_{S}^{0}a_{0}(980)^{+} using 2.93  fb^{-1} of e^{+}e^{-} collision data taken at a center-of-mass energy of 3.773 GeV with the BESIII detector. As the only W-annihilation-free decay among D to a_{0}(980) pseudoscalar, D^{+}→K_{S}^{0}a_{0}(980)^{+} is the ideal decay in extracting the contributions of the W-emission amplitudes involving a_{0}(980) and to study the final-state interactions. The absolute branching fraction of D^{+}→K_{S}^{0}π^{+}η is measured to be (1.27±0.04_{stat}±0.03_{syst})%. The branching fractions of intermediate processes D^{+}→K_{S}^{0}a_{0}(980)^{+} with a_{0}(980)^{+}→π^{+}η and D^{+}→π^{+}K[over ¯]_{0}^{*}(1430)^{0} with K[over ¯]_{0}^{*}(1430)^{0}→K_{S}^{0}η are measured to be (1.33±0.05_{stat}±0.04_{syst})% and (0.14±0.03_{stat}±0.01_{syst})%, respectively.

Observation of Significant Flavor-SU(3) Breaking in the Kaon Wave Function at 12<Q^{2}<25 GeV^{2} and Discovery of the Charmless Decay ψ(3770)→K_{S}^{0}K_{L}^{0}

We present cross sections for the reaction e^{+}e^{-}→K_{S}^{0}K_{L}^{0} at center-of-mass energies ranging from 3.51 to 4.95 GeV using data samples collected in the BESIII experiment, corresponding to a total integrated luminosity of 26.5  fb^{-1}. The ratio of neutral-to-charged kaon form factors at large momentum transfers (12 Collapse

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Investigation of the ΔI=1/2 Rule and Test of CP Symmetry through the Measurement of Decay Asymmetry Parameters in Ξ^{-} Decays

Using (10087±44)×10^{6}  J/ψ events collected with the BESIII detector, numerous Ξ^{-} and Λ decay asymmetry parameters are simultaneously determined from the process J/ψ→Ξ^{-}Ξ[over ¯]^{+}→Λ(pπ^{-})π^{-}Λ[over ¯](n[over ¯]π^{0})π^{+} and its charge-conjugate channel. The precisions of α_{Λ0} for Λ→nπ^{0} and α[over ¯]_{Λ0} for Λ[over ¯]→n[over ¯]π^{0} compared to world averages are improved by factors of 4 and 1.7, respectively. The ratio of decay asymmetry parameters of Λ→nπ^{0} to that of Λ→pπ^{-}, ⟨α_{Λ0}⟩/⟨α_{Λ-}⟩, is determined to be 0.873±0.012_{-0.010}^{+0.011}, where the first and the second uncertainties are statistical and systematic, respectively. The ratio is smaller than unity more than 5σ, which signifies the existence of the ΔI=3/2 transition in Λ for the first time. Besides, we test for CP symmetry in Ξ^{-}→Λπ^{-} and in Λ→nπ^{0} with the best precision to date.

Signature of quantum criticality in cuprates by charge density fluctuations

The universality of the strange metal phase in many quantum materials is often attributed to the presence of a quantum critical point (QCP), a zero-temperature phase transition ruled by quantum fluctuations. In cuprates, where superconductivity hinders direct QCP observation, indirect evidence comes from the identification of fluctuations compatible with the strange metal phase. Here we show that the recently discovered charge density fluctuations (CDF) possess the right properties to be associated to a quantum phase transition. Using resonant x-ray scattering, we studied the CDF in two families of cuprate superconductors across a wide doping range (up to p = 0.22). At p* ≈ 0.19, the putative QCP, the CDF intensity peaks, and the characteristic energy Δ is minimum, marking a wedge-shaped region in the phase diagram indicative of a quantum critical behavior, albeit with anomalies. These findings strengthen the role of charge order in explaining strange metal phenomenology and provide insights into high-temperature superconductivity.

[Evaluation of drug-drug interactions between yimitasvir phosphate capsules with sofosbuvir tablets, omeprazole magnesium enteric-coated tablets, and rosuvastatin calcium tablets]

Objective: To evaluate the drug-drug interactions and the tolerability of combined medication between yimitasvir phosphate capsules with sofosbuvir tablets, omeprazole magnesium enteric-coated tablets, and rosuvastatin calcium tablets in healthy volunteers. Methods: A randomized, open, and continuous administration design was used in trial 1 (yimitasvir phosphate capsules with sofosbuvir tablets). 28 subjects were randomly divided into two groups. A non-randomized, open design was used in trial 2 (yimitasvir phosphate capsules with omeprazole magnesium enteric-coated tablets), and included 42 subjects divided into three groups. The open design method was used in trial 3 (yimitasvir phosphate capsules with rosuvastatin calcium tablets), and included 14 subjects. The plasma concentrations of yimitasvir phosphate, sofosbuvir and their main metabolites GS-331007, omeprazole and rosuvastatin were validated by a liquid chromatography/tandem mass spectrometry (LC-MS/MS). The pharmacokinetic parameters were calculated by Phoenix winNonlin software. Results: (1) in trial 1, after single and co-administration, the 90% CI of sofosbuvir C(max) and AUC(0-tau) geometric mean ratio (GMR) were 152.0% (118.0% ~ 197.0%) and 230.0% (184.0% ~ 287.0%), with an increase of 52.0% and 130.0% compared to single dose of sofosbuvir, respectively. The 90% CI of GS-331007 C(max) GMR was 74.0% (67.5% ~ 81.2%) and reduced by 26% compared to single dose of sofosbuvir. (2) in trial 2, the 90% CI of C(max) GMR after yimitasvir single or co-administration at the same time, with a 4-hours interval, or with a 12- hours interval were 68.9% (44.5% ~ 106.7%) , 64.0% (43.8% ~ 93.6%) and 56.4%(38.9% ~ 81.9%), and the 90% CI of AUC(0-t) GMR were 68.6% (46.5% ~ 101.2%), 68.3% (47.6% ~ 98.0%) and 60.5% (41.8% ~ 87.5%), respectively. Compared with single dose of yimitasvir, the C(max) and AUC(0-t) were decreased by 31.1% and 31.4%, 36.0% and 31.7%, 43.6% and 39.5%, respectively. (3) In trial 3, after single and co-administration, the 90% CI of rosuvastatin C(max) and AUC(0-72) GMR were 172.4% (153.6% ~ 193.5%) and 158.0% (144.3% ~ 172.9%), respectively, with an increase of 74.9% and 60.5% compared to single dose of rosuvastatin. There were no serious adverse events and adverse events leading to withdrawal from the trial. Conclusion: Yimitasvir phosphate capsules have drug-drug interactions with sofosbuvir tablets, omeprazole magnesium enteric-coated tablets, and rosuvastatin calcium tablets.

Large Polarons as Key Quasiparticles in SrTiO_{3} and SrTiO_{3}-Based Heterostructures

Despite its simple structure and low degree of electronic correlation, SrTiO_{3} (STO) features collective phenomena linked to charge transport and, ultimately, superconductivity, that are not yet fully explained. Thus, a better insight into the nature of the quasiparticles shaping the electronic and conduction properties of STO is needed. We studied the low-energy excitations of bulk STO and of the LaAlO_{3}/SrTiO_{3} two-dimensional electron gas (2DEG) by Ti L_{3} edge resonant inelastic x-ray scattering. In all samples, we find the hallmark of polarons in the form of intense dd+phonon excitations, and a decrease of the LO3-mode electron-phonon coupling when going from insulating to highly conducting STO single crystals and heterostructures. Both results are attributed to the dynamic screening of the large polaron self-induced polarization, showing that the low-temperature physics of STO and STO-based 2DEGs is dominated by large polaron quasiparticles.

Enhanced Electron-Phonon Coupling for Charge-Density-Wave Formation in La_{1.8-x}Eu_{0.2}Sr_{x}CuO_{4+δ}

Charge density wave (CDW) correlations are prevalent in all copper-oxide superconductors. While CDWs in conventional metals are driven by coupling between lattice vibrations and electrons, the role of the electron-phonon coupling (EPC) in cuprate CDWs is strongly debated. Using Cu L_{3} edge resonant inelastic x-ray scattering, we study the CDW and Cu-O bond-stretching phonons in the stripe-ordered cuprate La_{1.8-x}Eu_{0.2}Sr_{x}CuO_{4+δ}. We investigate the interplay between charge order and EPC as a function of doping and temperature and find that the EPC is enhanced in a narrow momentum region around the CDW ordering vector. By detuning the incident photon energy from the absorption resonance, we extract an EPC matrix element at the CDW ordering vector of M≃0.36  eV, which decreases to M≃0.30  eV at high temperature in the absence of the CDW. Our results suggest a feedback mechanism in which the CDW enhances the EPC which, in turn, further stabilizes the CDW.

Dynamical charge density fluctuations pervading the phase diagram of a Cu-based high-T c superconductor

Charge density modulations have been observed in all families of high-critical temperature (T _c) superconducting cuprates. Although they are consistently found in the underdoped region of the phase diagram and at relatively low temperatures, it is still unclear to what extent they influence the unusual properties of these systems. Using resonant x-ray scattering, we carefully determined the temperature dependence of charge density modulations in YBa₂Cu₃O_7-δ and Nd_{1+ x} Ba_{2- x} Cu₃O_7-δ for several doping levels. We isolated short-range dynamical charge density fluctuations in addition to the previously known quasi-critical charge density waves. They persist up to well above the pseudogap temperature T*, are characterized by energies of a few milli-electron volts, and pervade a large area of the phase diagram.

[The prevalence and related factors of HBV infection among adults in Mianyang]

Objective: To analyze the prevalence and related factors of HBV infection among people aged 18 years old and above in Mianyang city. Methods: A total of 260 950 residents, living in Mianyang city more than 6 months, aging 18 years old and above were employed by multi-stage random sampling method from November 2014 to September 2015. Questionnaire survey was conducted on participants using a self-designed questionnaire, including general demographic characteristics, family history of Hepatitis B, history of Hepatitis B vaccination and history of present illness, etc. 5ml blood was collected from all participants, and the blood samples were detected for HBsAg by enzyme-linked immunosorbent assay (ELISA). The multivariate unconditional logistic regression was performed to identify the related factors of positive HBsAg. Results: Among the 260 950 subjects, 113 184 were males (43.37%), 147 766 were females (56.63%), and the average age was (47.68±17.36) years old. The positive rate of HBsAg was 6.10%(15 822 cases). Subjects who were 25-34 years old (OR=1.23), 35-44 years old (OR=1.26), 45-54 years old (OR=1.23), and 55-64 years old (OR=1.34) were more likely to be HBsAg positive,65 years and older (OR=0.88) were less likely to be, compared with subjects aging 18-24 years old; males were more likely to be HBsAg positive compared with females (OR=1.35); people living in Fucheng district were more likely to be HBsAg positive compared with who living in Jiangyou district(OR=1.91); married people were more likely to be HBsAg positive compared with unmarried ones (OR=1.36); medical staff were less likely to be HBsAg positive compared with non-medical staff (OR=0.61); subjects with a surgery history were more likely to HBsAg positive compared with who without (OR=1.13); subjects with trauma history were more likely to HBsAg positive compared with who without (OR=1.13); people with history of Hepatitis B were more likely to HBsAg positive compared with who without (OR=4.21); people with Hepatitis B vaccination history were less likely to be HBsAg positive compared with who without (OR=0.48); all the P values above were less than 0.05. Conclusion: The positive rate of HBsAg among adults in Mianyang city was very high, and we should pay more attention to people aging between 25 and 64 years old, male, medical staff, with surgery history, trauma history, and a family history of Hepatitis B and Hepatitis B vaccination history.

[Study on weight gain in different stages of pregnancy and pregnancy outcomes]

Objective: By investigating the relationship of pregestational body mass index(BMI), trimester-specific gestational weight gain (rate) during the first, second, third and total trimesters of pregnancy with adverse pregnant outcomes, to evaluate the effects of different pregestational BMI, trimester-specific gestational weight gain on pregnant outcomes, and to provide evidences for gestational weight control. Methods: From April 2015 to January 2016, 964 pregnant women in Zhejiang Taizhou First People's Hospital and Taizhou Huangyan Maternal & Child Care Service Center were enrolled in random for prospective study and were divided into groups according to the Institute of Medicine 2009 guidelines[IOM2009]. (1)They were divided into four groups according to pregestational BMI: low body mass, normal body mass, over body mass and obese group.(2)They were divided into three groups according to trimester-specific gestational weight gain (rate): normal gestational weight gain, insufficient gestational weight gain and excessive gestational weight gain.(3)The gestational weight gain and pregnant outcomes were recorded by using self-made information table, including the incidence rates of gestational diabetes mellitus (GDM), neonatal birth weight (BW), hypertensive disorders complicating pregnancy (HDCP), cesarean section, pliers delivery, shoulder dystocia, fetal macrosomia, small for gestational age (SGA), premature rupture of membranes, neonatal asphyxia, and neonatal hypoglycemia. Results: (1)In this study, 964 pregnant women were enrolled, no significant differences were found in terms of age, culture level, pregnancy times and delivery times of the different pregestational BMI groups (P>0.05). (2)The incidences of GDM, HDCP, premature rupture of membranes, cesarean section, pliers delivery, shoulder dystocia, fetal macrosomia, SGA, neonatal asphyxia and neonatal hypoglycemia were as dependent variables and trimester-specific gestational weight gain (rate) was as independent variable.Multivariate Logistic regression analysis showed that the pregnancy obesity was associated with increased risks of GDM and HDCP, the OR values were 6.63 and 2.60 (P<0.05). The excessive gestational weight gain (rate) of the total trimester of pregnancy was associated with increased risks of GDM, fetal macrosomia and cesarean section, the OR values were 2.05, 1.36 and 1.60, (P<0.05). There was no statistical significance in other groups (P>0.05). (3)Compared to the normal groups, the pregnancy obesity and excessive gestational weight gain of the first, second, third and total trimesters of pregnancy were all associated with an increased risk of GDM, the OR values were 7.36, 1.61, 1.81, 2.20 and 2.4 (P<0.05), respectively.The incidences of HDCP, cesarean section and neonatal hypoglycemia in pregnant women with GDM were higher than those in normal pregnant women (P<0.05). Conclusion: There is a significant correlation among pregestational BMI, gestational weight gain (rate) during the first, second, third and total trimesters of pregnancy with adverse pregnant outcomes, and it suggested that we could reduce the incidence of adverse pregnant outcomes by pre-pregnancy BMI and gestational weight control, and the focus should be placed on pre-pregnancy BMI control.

Three-dimensional collective charge excitations in electron-doped copper oxide superconductors

High-temperature copper oxide superconductors consist of stacked CuO₂ planes, with electronic band structures and magnetic excitations that are primarily two-dimensional^1,2, but with superconducting coherence that is three-dimensional. This dichotomy highlights the importance of out-of-plane charge dynamics, which has been found to be incoherent in the normal state^3,4 within the limited range of momenta accessible by optics. Here we use resonant inelastic X-ray scattering to explore the charge dynamics across all three dimensions of the Brillouin zone. Polarization analysis of recently discovered collective excitations (modes) in electron-doped copper oxides^5-7 reveals their charge origin, that is, without mixing with magnetic components^5-7. The excitations disperse along both the in-plane and out-of-plane directions, revealing its three-dimensional nature. The periodicity of the out-of-plane dispersion corresponds to the distance between neighbouring CuO₂ planes rather than to the crystallographic c-axis lattice constant, suggesting that the interplane Coulomb interaction is responsible for the coherent out-of-plane charge dynamics. The observed properties are hallmarks of the long-sought 'acoustic plasmon', which is a branch of distinct charge collective modes predicted for layered systems^8-12 and argued to play a substantial part in mediating high-temperature superconductivity^10-12.

Re-entrant charge order in overdoped (Bi,Pb)2.12Sr1.88CuO6+δ outside the pseudogap regime

In the underdoped regime, the cuprate high-temperature superconductors exhibit a host of unusual collective phenomena, including unconventional spin and charge density modulations, Fermi surface reconstructions, and a pseudogap in various physical observables. Conversely, overdoped cuprates are generally regarded as conventional Fermi liquids possessing no collective electronic order. In partial contradiction to this widely held picture, we report resonant X-ray scattering measurements revealing incommensurate charge order reflections for overdoped (Bi,Pb)_2.12Sr_1.88CuO_6+δ (Bi2201), with correlation lengths of 40-60 lattice units, that persist up to temperatures of at least 250 K. The value of the charge order wavevector decreases with doping, in line with the extrapolation of the trend previously observed in underdoped Bi2201. In overdoped materials, however, charge order coexists with a single, unreconstructed Fermi surface without nesting or pseudogap features. The discovery of re-entrant charge order in Bi2201 thus calls for investigations in other cuprate families and for a reconsideration of theories that posit an essential relationship between these phenomena.

Modelling of focused ion beam induced increases in sample temperature: a case study of heat damage in biological samples

Ion beam induced heat damage in soft materials and biological samples is not yet well understood in Focused Ion Beam systems (FIBs). The work presented here discusses the physics behind the ion beam - sample interactions and the effects which lead to increases in sample temperature and potential heat damage. A model by which heat damage can be estimated and which allows parameters to be determined that reduce/prevent heat damage was derived from Fourier's law of heat transfer and compared to finite element simulations, numerical modelling results and experiments. The results suggests that ion beam induced heat damage can be prevented/minimised by reducing the ion beam current (local dose rate), decreasing the beam overlap (reduced local ion dose) and by introducing a blur (increased surface cross-section area, reduced local dose) while sputtering, patterning or imaging soft material and nonresin-embedded biological samples using FIBs.

LAY DESCRIPTION

FIB/SEMs, which combine a scanning electron microscope with a focused ion beam in a single device, have found increasing interest biological research. The device allows to cut samples at precisely selected areas and reveal sub surface information as well as preparing transmission electron microscope samples from bulk materials. Preparing biological samples has proven to be challenging due to the induced heat damage. This work explores the physics behind the sample cutting and proposes a model and a method, based on physical principles which allows the user to estimate the induced heat during the cutting process and to select cutting parameters which avoid heat damage in the sample.

[Study of bioequiavailability of paclitaxel for Injection (Albumin Bound) and abraxane and the efficacy of extension treatments in patients with metastatic breast cancer]

Objective: To compare the bioequiavailability of paclitaxel for injection (albumin bound) (PAB) and reference listed drug abraxane in the patients with metastatic breast cancer, and to investigate the safety and efficacy in the extension treatments of PAB. Methods: This study was random, two cycles, self-crossover control study in the bioequiavailability stage. PAB was the investigational drug T and Abraxane was the reference drug R. Patients were randomly assigned to two cycles therapy of either R→T or T→R(260 mg/m(2)/21d). Non-PD patients entered in the extension treatments of the investigational drug PAB(260 mg/m(2)/21d) until the disease progression or the intolerance toxicity. Results: From Mar 1, 2016 to May 24, 2016, we enrolled 40 patients. The blood concentration-time curve and the parameters of pharmacokinetics indicated the two drugs were the bioequivalent drug products in the initial two cycles crossover-therapy.The incidence of adverse drug reactions were 89.7% vs 97.4% in investigational drug vs reference drug and grade 3/4 toxicities were 20.5% vs 21.1%(P=1.000). Patients received a median of 7 treatment cycles(range 1-23) and a median of 260mg/m(2) actual drug dose (range 220-260 mg/m(2)). Seven patients (17.5%) had dose reductions because of toxicities (260 mg/m(2) reduce to 220 mg/m(2)). Twenty-two patients (55%) discontinued treatment prematurely because of toxicity.Overall response rates (ORR) were 40% (95% CI, 24.8%-55.2%). For patients who received PAB as first-line vs non-first-line therapy, the ORR were 43.8% vs 25%. For patients who taxane-naïve vs taxane-pretreated, the ORR were 45.5% vs 37.9%. Median PFS was 49 weeks(95% CI, 30weeks-NA). Conclusion: The paclitaxel for injection (albumin bound) (PAB) and reference listed drug abraxane are the bioequivalent drug products.The toxicity and efficacy of the PAB are similar with abraxane.The more therapy chances for Chinese patients will come by the research and development of domestic drugs.

Crossover from Collective to Incoherent Spin Excitations in Superconducting Cuprates Probed by Detuned Resonant Inelastic X-Ray Scattering

Spin excitations in the overdoped high temperature superconductors Tl_{2}Ba_{2}CuO_{6+δ} and (Bi,Pb)_{2}(Sr,La)_{2}CuO_{6+δ} were investigated by resonant inelastic x-ray scattering (RIXS) as functions of doping and detuning of the incoming photon energy above the Cu-L_{3} absorption peak. The RIXS spectra at optimal doping are dominated by a paramagnon feature with peak energy independent of photon energy, similar to prior results on underdoped cuprates. Beyond optimal doping, the RIXS data indicate a sharp crossover to a regime with a strong contribution from incoherent particle-hole excitations whose maximum shows a fluorescencelike shift upon detuning. The spectra of both compound families are closely similar, and their salient features are reproduced by exact-diagonalization calculations of the single-band Hubbard model on a finite cluster. The results are discussed in the light of recent transport experiments indicating a quantum phase transition near optimal doping.

Non-animal collagens as new options for cosmetic formulation

OBJECTIVE

To examine the potential of non-animal collagens as a new option for cosmetic applications.

METHODS

Non-animal collagens from three species, Streptococcus pyogenes, Solibacter usitatus and Methylobacterium sp 4-46, have been expressed as recombinant proteins in Escherichia coli using a cold-shock, pCold, expression system. The proteins were purified using either metal affinity chromatography or a simple process based on precipitation and proteolytic digestion of impurities, which is suitable for large-scale production. Samples were examined using a range of analytical procedures.

RESULTS

Analyses by gel electrophoresis and mass spectrometry were used to examine the purity and integrity of the products. Circular dichroism spectroscopy showed stabilities around 38°C, and calculated pI values were from 5.4 to 8.6. UV-visible light spectroscopy showed the clarity of collagen solutions. The collagens were soluble at low ionic strength between pH 5 and pH 8, but were less soluble under more acidic conditions. At lower pH, the insoluble material was well dispersed and did not form the fibrous associations and aggregates found with animal collagens. The materials were shown to be non-cytotoxic to cells in culture.

CONCLUSIONS

These novel, non-animal collagens may be potential alternatives to animal collagens for inclusion in cosmetic formulations.

Collective nature of spin excitations in superconducting cuprates probed by resonant inelastic X-ray scattering

We used resonant inelastic x-ray scattering (RIXS) with and without analysis of the scattered photon polarization, to study dispersive spin excitations in the high temperature superconductor YBa_{2}Cu_{3}O_{6+x} over a wide range of doping levels (0.1≤x≤1). The excitation profiles were carefully monitored as the incident photon energy was detuned from the resonant condition, and the spin excitation energy was found to be independent of detuning for all x. These findings demonstrate that the largest fraction of the spin-flip RIXS profiles in doped cuprates arises from magnetic collective modes, rather than from incoherent particle-hole excitations as recently suggested theoretically [Benjamin et al. Phys. Rev. Lett. 112, 247002 (2014)]. Implications for the theoretical description of the electron system in the cuprates are discussed.

The effects of recombinant human epithelialgrowth factor and protein-free calf blood extract for recovery of corneal mechanical epithelial defects healing and neovascularization

OBJECTIVE

This study was undertaken to investigate the effects of recombinant human epidermal growth factor (rhEGF) and protein-free calf blood extract on corneal wound healing and neovascularization.

MATERIALS AND METHODS

An rabbit central corneal wound and neovascularization model was established in rabbits. One eye of each group was chosen randomly for topical administration of protein-free calf blood extract, rhEGF, or NS (physiological saline), and variability in the area of corneal epithelial wound healing and neovascularization was observed.

RESULTS

On days 1 and 2, the healing rate of corneal epithelium was various among the protein-free calf blood extract group, rhEGF group and NS group (F=6.475, p=0.012). The healing rate of corneal epithelium in the rhEGF group was better than the protein-free calf blood extract group (p=0.004) and NS group (p=0.041) on day 1. The corneal neovascularization area in the protein-free calf blood extract group was less than that of rhEGF group (p=0.04) and NS group (p=0.008) on day 18.

CONCLUSIONS

rhEGF had better promotive effect on corneal epithelial wound healing than the protein-free calf blood extract in the advanced phase (within 2 days). Both rhEGF and protein-free calf blood extract were not found to promote.

Lower limb gangrene postcardiac surgery

A 67-year-old gentleman presented with a 1-day history of left foot pain. He had recently been discharged following a coronary artery bypass graft; during the admission, he had received an intravenous heparin infusion. Examination revealed black-purple discolouration of the first and second digits of the left foot with pitting oedema to the level of the knee. The posterior tibial and dorsalis pedis pulses were both shown to be patent. A new thrombocytopenia was noted. Ultrasound imaging revealed multiple deep vein thrombosis. The history of recent heparin exposure coupled with venous gangrene secondary to deep vein thrombosis was consistent with heparin-induced thrombocytopenia. He was treated acutely with intravenous danaparoid and later with warfarin. There was complete resolution of the venous gangrene at 1 month follow-up.

New thrombopoietin receptor agonists for platelet disorders

Since thrombopoietin (TPO) was cloned in 1994, TPO receptor (TPO-R) agonists have been developed which have shown significant clinical activity in various conditions characterized by thrombocytopenia. First-generation TPO-R agonists were recombinant forms of human TPO. The clinical development of these molecules was discontinued after one of them, pegylated recombinant human megakaryocyte growth and development factor, was associated with the development of neutralizing autoantibodies cross-reacting with endogenous TPO. Second-generation TPO-R agonists are now available, which present no sequence homology to endogenous TPO. Two of these new agents, romiplostim and eltrombopag, have been granted marketing authorization for use in patients with primary immune thrombocytopenia unresponsive to conventional treatments. Clinical trials with TPO-R agonists are also ongoing in other thrombocytopenias, such as hepatitis C virus-related thrombocytopenia and the myelodysplastic syndromes.

Recent developments in the use of adenoviruses and immunotoxins in cancer gene therapy

Despite setbacks in the past and apparent hurdles ahead, gene therapy is advancing toward reality. The past several years have witnessed this new field of biomedicine developing rapidly both in breadth and depth, especially for the treatment of cancer, thanks largely to the better understanding of molecular and genetic basis of oncogenesis and the development of new and improved vectors and technologies for gene delivery and targeting. This article is intended to provide a brief review of recent advances in cancer gene therapy using adenoviruses, both as vectors and as oncolytic agents, and some of the recent progress in the development of immunotoxins for use in cancer gene therapy.

Determination of isoflavones in red clover by capillary electrophoresis with electrochemical detection

Capillary electrophoresis with electrochemical detection (CE-ED) was employed to analyze isoflavones in red clover (Trifolium pratense). The effects of potential of working electrode, pH and concentration of running buffer, separation voltage and injection time on CE-ED were investigated. Operated in a wall-jet configuration, a 300 microm diameter carbon-disk electrode was used as the working electrode, which exhibits a good response at +0.85 V (versus saturated calomel electrode) for the analytes. The analytes could be separated in a 50 mmol/l borate buffer (pH 9.5) within 25 min. The response was linear over three orders of magnitude with detection limit (S/N=3) ranging from 2x10(-5) mg/ml to 5x10(-5) mg/ml for the analytes. This method has been used for the determination of daidzein, genistein and biochanin A in red clover with satisfactory results.

The antihypertensive and cardioprotective effects of (-)-MJ-451, an ATP-sensitive K(+) channel opener

ATP-sensitive K(+) (K(ATP)) channel openers have been shown to be a potential class of therapeutic agents for the control of cardiovascular diseases, including angina, arrhythmias, and hypertension. In this study, the pharmacological activity of 6-cyano-3S,4R-dihydro-2, 2-dimethyl-2H-3-hydroxy-4-[5S-(1-hydroxymethyl)-2-oxo-1-pyrrolidinyl] -1-benzopyran ((-)-MJ-451), a synthetic K(ATP) opener, was evaluated in anesthetized rat models and in isolated rat thoracic rings. Results demonstrated that intravascular injection of (-)-MJ-451 (0. 02, 0.05 and 0.1 mg/kg) produced an immediate, dose-related reduction in mean arterial blood pressure in anesthetized spontaneously hypertensive rats (SHR), which persisted for more than 3 h and was not accompanied by reflex tachycardia. The hemodynamic changes were completely abolished by pretreatment with glibenclamide (4 mg/kg, i.v. bolus), a selective K(ATP) channel blocker. In isolated thoracic aorta, (-)-MJ-451 (10 nM-3 microM) produced a concentration-dependent vasodilator effect on the phenylephrine (0.3 microM)-induced vasoconstriction. Moreover, (-)-MJ-451 relaxed the thoracic aorta contracted by low (5, 20 and 30 mM), but not high (40 and 60 mM) concentrations of extracellular potassium. In addition, (-)-MJ-451 showed cardioprotective effects in the rat model of 45-min left coronary artery occlusion followed by 1-h reperfusion. In myocardial ischemia, pretreatment with (-)-MJ-451 (2, 5 and 10 microg/kg, i.v. bolus) significantly reduced the incidence of ventricular fibrillation and the mortality, also reducing the total number of ventricular premature contractions, total duration of ventricular tachycardia and ventricular fibrillation. A significant reduction in infarct size was noted in three (-)-MJ-451 (2, 5 and 10 microg/kg)-treated groups. Also, the cardioprotective effects of (-)-MJ-451 were virtually abolished by pretreating the rats with glibenclamide (4 mg/kg, i.v. bolus). In conclusion, (-)-MJ-451, through opening the K(ATP) channel, exerted antihypertensive and cardioprotective effects. Therefore, it is suggested that (-)-MJ-451 has potential in the treatment of hypertension or acute myocardial infarction.

A four-compartment model for Ca2+ dynamics: an interpretation of Ca2+ decay after repetitive firing of intact nerve terminals

In the presynaptic nerve terminals of the bullfrog sympathetic ganglia, repetitive nerve firing evokes [Ca2+] transients that decay monotonically. An algorithm based on an eigenfunction expansion method was used for fitting these [Ca2+] decay records. The data were fitted by a linear combination of two to four exponential functions. A mathematical model with three intraterminal membrane-bound compartments was developed to describe the observed Ca2+ decay. The model predicts that the number of exponential functions, n, contained in the decay data corresponds to n-1 intraterminal Ca2+ stores that release Ca2+ during the decay. Moreover, when a store stops releasing or starts to release Ca2+, the decay data should be fitted by functions that contain one less exponential component for the former and one more for the latter than do the fitting functions for control data. Because of the current lack of a parameter by which quantitative comparisons can be made between two decay processes when at least one of them contained more than one exponential components, we defined a parameter, the overall rate (OR) of decay, as the trace of the coefficient matrix of the differential equation systems of our model. We used the mathematical properties of the model and of the OR to interpret effects of ryanodine and of a mitochondria uncoupler on Ca2+ decay. The results of the analysis were consistent with the ryanodine-sensitive store, mitochondria, and another, yet unidentified store release Ca2+ into the cytosol of the presynaptic nerve terminals during Ca2+ decay. Our model also predicts that mitochondrial Ca2+ buffering accounted for more than 86% of all the flux rates across various membranes combined and that there are type 3 and type 1 and/or type 2 ryanodine receptors in these terminals.

The effects of a newly synthesized ATP-sensitive potassium channel opener, MJ-355, on blood pressure and myocardial ischemia-reperfusion injury in rats

ATP-sensitive potassium (K(ATP)) channel openers, exerting a potent vasodilatory action, are useful in the treatment of cardiovascular disorders; e.g., hypertension and angina pectoris. This study was designed to evaluate the effect of MJ-355 (6-cyano-3,4-trans-3,4-dihydro-2,2-dimethyl-2H-3-hydroxy-4-[2-oxo-5S-(1- ethoxyethoxymethyl)-1-pyrrolidinyl]-1-benzopyran), a newly synthesized K(ATP) channel opener, on hemodynamics in spontaneously hypertensive rats and on myocardial ischemia-reperfusion injury in a rat model of 45 min left coronary artery occlusion followed by 1-h reperfusion. Intravascular injection of MJ-355 (0.005, 0.05 and 0.1 mg/kg) produced a dose-related reduction in mean arterial blood pressure. The depressor effect started 10-15 min after the administration and persisted for more than 3 h and was not accompanied by a reflex tachycardia. In myocardial ischemia, pretreatment of MJ-355 (0.02 mg/kg) significantly reduced the total number of ventricular premature contractions and ventricular tachycardia, total duration of ventricular fibrillation and the mortality. Additionally, a significant reduction in infarct size was noted in all of the MJ-355-treated groups. The hemodynamic and cardioprotective effects of MJ-355 were virtually abolished by pretreating the rats with glibenclamide (4 mg/kg, i.v. bolus), a selective K(ATP) channel blocker. In conclusion, MJ-355, through the activation of K(ATP) channels, exhibited antihypertensive and cardioprotective effects. It is suggested that MJ-355 should be useful in the treatment of hypertension and/or acute myocardial infarction.

Caffeine and carbonyl cyanide m-chlorophenylhydrazone increased evoked and spontaneous release of luteinizing hormone-releasing hormone from intact presynaptic terminals

In bullfrog sympathetic ganglia, the ryanodine-sensitive Ca2+ store and mitochondria modulate [Ca2+] within nerve terminals. We used caffeine (10 mM) and carbonyl cyanide m-chlorophenylhydrazone (10 microM) to assess how these Ca2+ stores affect release of a neuropeptide, luteinizing hormone-releasing hormone, from these nerve terminals. Release of luteinizing hormone-releasing hormone was evoked by electrical stimulation to presynaptic nerves and was monitored as a late slow excitatory postsynaptic potential in ganglionic neurons. Caffeine increased release of luteinizing hormone-releasing hormone similarly whether the release was evoked by 4 or 20 Hz stimulations (by 2.7 +/- 1.1- and 3.2 +/- 0.9-fold, mean +/- S.E.M., n = 27, respectively). Carbonyl cyanide m-chlorophenylhydrazone augmented release of luteinizing hormone-releasing hormone evoked by 4 Hz stimulation much more strongly (by 11.8 +/- 1.8-fold) than it increased the release evoked by 20 Hz stimulation (by 3.6 +/- 1.3-fold, n = 25). We detected spontaneous release of luteinizing hormone-releasing hormone as a slow hyperpolarization in response to a brief application of an antagonist to the receptors for luteinizing hormone-releasing hormone in 65% (34 of 52) and 39% (11 of 28) of the ganglionic B and C neurons, respectively. Caffeine increased spontaneous release of luteinizing hormone-releasing hormone by 2.3 +/- 0.7-fold (n = 6) whereas carbonyl cyanide m-chlorophenylhydrazone increased this release by 4.27- and 1.76-fold (n = 2). Facilitation of Ca2+ release from the intracellular store by caffeine and inhibition of mitochondrial Ca2+ removal by carbonyl cyanide m-chlorophenylhydrazone increased spontaneous as well as evoked release of luteinizing hormone-releasing hormone. Moreover, caffeine increments of evoked release did not depend on the firing frequency of the nerve whereas carbonyl cyanide m-chlorophenylhydrazone augmentations of evoked release strongly depended on the firing frequency.

Dense-cored vesicles, smooth endoplasmic reticulum, and mitochondria are closely associated with non-specialized parts of plasma membrane of nerve terminals: implications for exocytosis and calcium buffering by intraterminal organelles

To determine whether there are anatomical correlates for intraterminal Ca2+ stores to regulate exocytosis of dense-cored vesicles (DCVs) and whether these stores can modulate exocytosis of synaptic vesicles, we studied the spatial distributions of DCVs, smooth endoplasmic reticulum (SER), and mitochondria in 19 serially reconstructed nerve terminals in bullfrog sympathetic ganglia. On average, each bouton had three active zones, 214 DCVs, 26 SER fragments (SERFs), and eight mitochondria. DCVs, SERFs and mitochondria were located, on average, 690, 624, and 526 nm, respectively, away from active zones. Virtually no DCVs were within "docking" (i.e., < or = 50 nm) distances of the active zones. Thus, it is unlikely that DCV exocytosis occurs at active zones via mechanisms similar to those for exocytosis of synaptic vesicles. Because there were virtually no SERFs or mitochondria within 50 nm of any active zone, Ca2+ modulation by these organelles is unlikely to affect ACh release evoked by a single action potential. In contrast, 30% of DCVs and 40% of SERFs were located within 50 nm of the nonspecialized regions of the plasma membrane. Because each bouton had at least one SERF within 50 nm of the plasma membrane and most of these SERFs had DCVs, but not mitochondria, near them, it is possible for Ca2+ release from the SER to provide the Ca2+ necessary for DCV exocytosis. The fact that 60% of the mitochondria had some part within 50 nm of the plasma membrane means that it is possible for mitochondrial Ca2+ buffering to affect DCV exocytosis.

Activation of nicotinic receptor-induced postsynaptic responses to luteinizing hormone-releasing hormone in bullfrog sympathetic ganglia via a Na+-dependent mechanism

Nicotine at very low doses (5-30 nM) induced large amounts of luteinizing hormone-releasing hormone (LHRH) release, which was monitored as slow membrane depolarizations in the ganglionic neurons of bullfrog sympathetic ganglia. A nicotinic antagonist, d-tubocurarine chloride, completely and reversibly blocked the nicotine-induced LHRH release, but it did not block the nerve-firing-evoked LHRH release. Thus, nicotine activated nicotinic acetylcholine receptors and produced LHRH release via a mechanism that is different from the mechanism for evoked release. Moreover, this release was not caused by Ca2+ influx through either the nicotinic receptors or the voltage-gated Ca2+ channels because the release was increased moderately when the extracellular solution was changed into a Ca2+-free solution that also contained Mg2+ (4 mM) and Cd2+ (200 microM). The release did not depend on Ca2+ release from the intraterminal Ca2+ stores either because fura-2 fluorimetry showed extremely low Ca2+ elevation (approximately 30 nM) in response to nicotine (30 nM). Moreover, nicotine evoked LHRH release when [Ca2+] elevation in the terminals was prevented by loading the terminals with 1,2-bis(2-aminophenoxy)ethane-N,N,N',N'-tetraacetic acid and fura-2. Instead, the nicotine-induced release required extracellular Na+ because substitution of extracellular NaCl with N-methyl-D-glucamine chloride completely blocked the release. The Na+-dependent mechanism was not via Na+ influx through the voltage-gated Na+ channels because the release was not affected by tetrodotoxin (1-50 microM) plus Cd2+ (200 microM). Thus, nicotine at very low concentrations induced LHRH release via a Na+-dependent, Ca2+-independent mechanism.

Aetiologies and prognosis of Chinese patients with deep vein thrombosis of the lower extremities

Deep vein thrombosis (DVT) of the lower extremities is not frequently encountered in Oriental patients. We investigated its aetiology and prognosis in 143 patients (65 males, 78 females), presenting to the National Taiwan University Hospital over 4.3 years, diagnosed by colour Doppler ultrasonography. Swelling and pain of the lower extremities were the most frequent presenting symptoms. The left femoropopliteal veins were more frequently involved than other parts of the lower extremities. In these patients, malignancy with or without intravenous catheterization was the most frequent cause (39 patients, 27%). Other common aetiologies included coagulopathy (29 patients, 20%), immobilization (24 patients, 17%) and catheter-related (13 patients, 9%). No definite aetiology could be determined in 37 patients (26%). During follow-up, 27 patients (19%) died, mostly with malignancy. Pulmonary embolism was noted in 16 patients and was not significantly directly related to death. Compared to similar studies in Caucasian patients, there were significant differences in the aetiology of DVT, with malignancy and coagulopathy more common in these Chinese patients.

Effects of mitochondrion on calcium transients at intact presynaptic terminals depend on frequency of nerve firing

The rate and the total amount of Ca2+ elevation in the presynaptic terminals of bullfrog sympathetic ganglia depend on the firing frequency of the terminals. Carbonyl cyanide m-chlorophenylhydrazone (CCCP), a mitochondrial uncoupler, was used for testing whether mitochondrial Ca2+ uptake is one of the mechanisms that underlie this frequency dependence. Fura-2 fluorimetry was used for measurement of intraterminal Ca2+. When stimulations of different durations (30 and 1.5 s) and frequencies (4 and 20 Hz) evoked Ca2+ transients with similar peak amplitudes (264 +/- 22 nM vs. 251 +/- 18 nM, means +/- SE), CCCP augmented the responses to the 4-Hz stimulation 8.9 times more strongly than it did the responses to the 20-Hz stimulation (249.7 +/- 81.5% vs. 25.3 +/- 10.2%). When stimulations delivered at the two frequencies had the same durations (1.5, 3, 6, 10, 20, and 30 s), CCCP enlarged the responses to the 4-Hz stimulations up to 4.2 times more than it did the responses to the 20-Hz stimulations. When the same number of stimuli (120) was delivered at the two frequencies, the effects of CCCP on the responses evoked by the 4-Hz train were again 6.8 times stronger than its effects on the responses to the 20-Hz stimulation. Therefore neither the peak amplitudes of the responses nor the durations of the stimulations dictated the extent to which the mitochondria modulated the peak [Ca2+]i. Instead, the extent of the modulation was governed by the frequency of stimulation. Specifically, the less frequent the Ca2+ influx, the stronger the mitochondrial modulation. Also, during nerve firing Ca2+ release from the ryanodine-sensitive store had a higher potential to influence the [Ca2+]i transients than did Ca2+ removal by the mitochondria for the first 6 s of the responses. On cessation of stimulation, CCCP reduced the initial rapid rate of Ca2+ decay. Thus uptake by the mitochondria was an important mechanism for Ca2+ removal after repetitive firing at the presynaptic terminals.

Losartan attenuates myocardial ischemia-induced ventricular arrythmias and reperfusion injury in spontaneously hypertensive rats

To assess the efficacy of losartan (2-n-butyl-4-chloro-5-hydroxymethyl-1-[(2'-(1H-tetrazol-5-yl)biphe nyl-4-yl)methyl]imidazole, potassium salt), an angiotensin II receptor antagonist, on acute myocardial ischemia, 36 four-month-old spontaneously hypertensive rats were used. The animals underwent 45 min of left coronary artery occlusion and 1 h of reperfusion and were randomly assigned to control and losartan-treated groups (2, 5, and 10 mg/kg, intravenously). Losartan was administered 15 min before ischemia. Electrocardiograms (lead II) were monitored continuously throughout the experiment. To assess the anti-infarct effect of losartan, the area at risk was determined by methylene blue dye and the infarct size was determined by nitroblue tetrazolium chloride staining. The areas of risk and infarct were measured by computerized planimetry. Results demonstrated that the low and intermediate doses (2 and 5 mg/kg) of losartan significantly decreased the incidence of ventricular fibrillation and mortality during the ischemic period induced by left coronary artery occlusion. However, a significant reduction in infarct size, calculated as a percentage of the area at risk, was noted in all three losartan-treated groups (control: 41.5% +/- 5.2%, losartan, 2 mg/kg: 11.2% +/- 5.8%, 5 mg/kg: 8.5% +/- 2.7% and 10 mg/kg: 13.7% +/- 1.6%). The results suggest that losartan may be useful in the treatment of ventricular arrhythmias induced by acute myocardial infarction and attenuation of reperfusion injury in hypertension.

Chicken GnRH II-like peptides and a GnRH receptor selective for chicken GnRH II in amphibian sympathetic ganglia

Amphibia, like most vertebrate species, have two forms of GnRH, namely [Arg8]GnRH (mammalian GnRH) and [His5,Trp7,Tyr8] GnRH (chicken GnRH II). The differential distribution of the two peptides in the amphibian brain suggests that they may play different roles. Mammalian GnRH, which is found predominantly in the hypothalamus, is most likely the prime regulator of gonadotropin release, while chicken GnRH II, which occurs predominantly in the midbrain and hindbrain, may play a neuromodulatory role. In amphibian sympathetic ganglia, GnRH has been demonstrated to be a neurotransmitter where its release from the presynaptic nerve terminals reversibly inhibits M current, a time- and voltage-dependent potassium current. The occurrence of GnRH in sympathetic ganglia extracts from two amphibian species was investigated. Chicken GnRH II-like immunoreactivity was detected in extracts of bullfrog (Rana catesbeiana) and platanna (Xenopus laevis) sympathetic ganglia after high performance liquid chromatography. Under the chromatographic conditions used, a second unknown peptide co-eluted with synthetic mammalian GnRH, but showed no cross-reactivity with specific mammalian GnRH antisera. To test the possibility of the presence of a chicken GnRH II receptor in sympathetic ganglion neurones, competition binding of membranes extracted from the sympathetic ganglia of the two amphibian species was investigated with 125I-labelled GnRH agonists. The binding of 125-I-[His5,D-Arg6,Trp7,Tyr8]GnRH (a chicken GnRH II agonist) to membranes from the sympathetic ganglia of both amphibian species was specific and had a higher affinity than chicken GnRH II, mammalian GnRH and a mammalian GnRH agonist [D-Ala6,NMe-Leu7,Pro9-NHEt]GnRH. These findings suggest that endogenous chicken GnRH II may play a role in synaptic transmission in the sympathetic ganglia via a receptor specific for chicken GnRH II.

Detection of minimal residual disease in childhood acute lymphoblastic leukemia after termination of therapy

Using IgH and TCR gamma gene rearrangements as gene markers, we detected minimal residual disease (MRD) by means of the polymerase chain reaction (PCR) and restriction analysis. Of 18 children with acute lymphoblastic leukemia (ALL), MRDs were detected in 9 patients after termination of therapy. All 18 patients had been followed for 1.5 to 102 months after detection. Three of the nine MRD-positive patients relapsed within 3 to 6 months; none of the nine MRD-negative patients relapsed. We suggest that MRD negativity at the end of therapy might be an important factor for long-term disease-free survival, because the negative cases had a very low risk of relapse. Because the outcome for MRD-positive cases is more difficult to evaluate, patients with MRD after termination of therapy should be monitored.

Changes of nuclear DNA content in different types of nasopharyngeal epithelium

The unclear DNA content was measured with flow cytometry (FCM) in 167 specimens of normal nasopharyngeal epithelium (NE), adjacent tissue to carcinoma (ATC) and nasopharyngeal carcinoma (NPC). All 20 patients with NE showed diploid, whereas 38 (38%) of 101 patients with NPC, 7 (58%) of 12 patients with recurrent NPC, 6 (30%) of 20 patients with ATC and 2 (33%) of 6 patients with NE, positive to EBVCA-IgA test, showed nondiploid. In addition, cellular proliferation index (PI) of diploid NPC and diploid ATC, though differed nonsignificantly, was significantly increased as compared with that of NE (P < 0.01). The rate of cervical metastasis in nondiploid NPC was significantly higher than that in diploid NPC (P < 0.025).

Release of LHRH is linearly related to the time integral of presynaptic Ca2+ elevation above a threshold level in bullfrog sympathetic ganglia

To study the Ca2+ dependency of luteinizing hormone-releasing hormone (LHRH) release in the bullfrog sympathetic ganglia, a method was developed to fill the preganglionic nerve terminal boutons with membrane-impermeant fura-2. We found that as stimulation frequency increased from 0.5 to 40 Hz, the peak [Ca2+]i ([Ca2+]p) and the rate of rise in [Ca2+]i increased, the decay of [Ca2+]i transients followed up to three exponentials, and release of LHRH was linearly related to integral of ([Ca2+]i--[Ca2+]t)dt. The threshold level of [Ca2+]i for LHRH release for a given set of boutons on a C cell, [Ca2+]t, was estimated by the [Ca2+]p evoked by 0.5 Hz stimulation that does not induce LHRH release.

Photoradiation therapy of animal tumors and nasopharyngeal carcinoma

Both animal tumors and human nasopharyngeal carcinoma were submitted to a photoradiation therapy (PRT) trial in order to determine the efficacy and side effects of PRT, as well as to elucidate its mechanism of cytotoxicity. In animal tumors, the inhibition rate was 70%, and of 20 patients, eight achieved complete remission, and ten, significant remission, with an overall response rate of 90%. The blood picture and the values of serum IgG, IgM, IgA, and C3 all remained stable post-PRT. Only three patients developed mild generalized skin photosensitive reactions, and these did not affect subsequent treatment. There was no immunosuppressive effect as evidenced by a tritium-labeled thymidine-incorporated lymphocytoblast transformation assay performed both before and after PRT. Ultrastructural studies at different time intervals after PRT highly suggested that the mitochondria and rough endoplasmic reticulum were among the first organelles to be damaged.

Activation of GABAB receptors causes presynaptic inhibition at synapses between muscle spindle afferents and motoneurons in the spinal cord of bullfrogs

Baclofen, a specific GABAB receptor agonist, was used to study the functional role of activation of GABAB receptors in synaptic transmission between muscle spindle afferents and motoneurons in the isolated spinal cord of bullfrogs. (+/-)-Baclofen (5 microM) reversibly reduced the amplitude of the excitatory postsynaptic potential (EPSP) evoked by simulation of various brachial muscle nerves and recorded extracellularly from the ventral root by 47% without shortening the falling phase of the EPSP. Neither the time course nor the amplitude of the action potentials in the sensory afferents was affected. Thus, baclofen caused synaptic inhibition without reducing either the potential change occurring in the muscle sensory afferents or the motoneuronal membrane resistance. Quantal analysis, performed using a deconvolution technique, of the monosynaptic EPSPs in brachial motoneurons evoked by activity in single triceps muscle spindle afferents showed that transmission at these synapses was quantal, and baclofen lowered the quantal content without altering the quantal size. Furthermore, quantal analysis of the electrical component of these unitary EPSPs showed that it did not fluctuate in amplitude, either in normal saline or with baclofen. The inhibition produced by activation of GABAB receptors is therefore presynaptic but is not likely to be caused by conduction failures in the sensory terminals.

Activation of GABAA receptors causes presynaptic and postsynaptic inhibition at synapses between muscle spindle afferents and motoneurons in the spinal cord of bullfrogs

The functional role of GABAA receptors in inhibition of synaptic transmission between muscle spindle afferents and spinal motoneurons was studied in the isolated spinal cord of bullfrogs. Extracellular recording from the ventral root showed that activation of GABAA receptors by muscimol (primarily a GABAA receptor agonist) at 50 microM produced a 38% reduction in the amplitude of the excitatory postsynaptic potential (EPSP) evoked by stimulation of triceps muscle sensory afferents and a 66% reduction in the EPSP half-width, suggesting a large increase in the conductance of the motoneuronal membrane. Quantal analysis of unitary triceps EPSPs recorded intracellularly from motoneurons showed that muscimol reduced the quantal content of release (presynaptic inhibition). In addition, muscimol decreased the quantal size (postsynaptic inhibition) when the postsynaptic conductance change was large. Because the effects of muscimol were completely and reversibly blocked by 100 microM bicuculline (a specific GABAA receptor antagonist), both the pre- and the postsynaptic inhibition caused by muscimol were due to activation of GABAA receptors. Activation of GABAA receptors thus causes both pre- and postsynaptic inhibition of synaptic transmission between muscle afferents and spinal cord motoneurons in the frog.

Anatomical specificity of regenerated muscle sensory afferents in the spinal cord of the bullfrog

The specificity of central projections made by regenerated muscle sensory fibers in the brachial spinal cord was studied with anatomical tracing methods. Sensory fibers were interrupted by freezing dorsal roots in postmetamorphic bullfrogs. After several months, regenerated sensory fibers were labeled with horseradish peroxidase applied to the triceps brachii muscle nerve, and their arborizations within the spinal cord were reconstructed from serial cross sections. Most of the regenerated projections from triceps muscle sensory afferents ended in or near their normal terminal field. A few branched and appeared to terminate more dorsally than normal, however, sometimes within the region where cutaneous afferents normally terminate. In contrast to the normal pathway followed by muscle afferents within the spinal cord, many regenerated afferents grew along the circumference of the spinal cord, just under the pial surface, and then turned abruptly toward the midline and into their appropriate terminal region. This suggests that regenerating afferents may actively seek out their appropriate targets and are not simply passively guided to them.