[Clinical features and outcomes: analysis of 9 cases of HIV-negtive plasmablastic lymphoma]

Objective: To evaluate the clinical features and outcomes of HIV-negtive plasmablastic lymphoma (PBL). Methods: Nine patients with HIV-negtive PBL were diagnosed and treated between January 2006 and January 2016. The clinical and follow-up data were analyzed retrospectively. Results: The median age was 56 years (range 30-77 years) with a male-to-female ratio of 2∶1. Nobody had underlying diseases associated with immunosuppression. Primary extra nodal diseases were observed in 7 cases and only 1 patient had oral involvement. Two patients were in earlystage and 7 in advanced stage by the Ann Arbor stage system. Ki-67 index was 60%-90% in the 9 cases, and 80% or higher in 7 cases. Epstein-Barr virus-encoded RNA expression (EBER) was detected in 4 cases, and 2 of them were positive. Chemotherapy was documented in 9 patients, from which 8 received the cyclophosphamide, doxorubicin, vincristine, prednisone (CHOP)-like regimens as the first-line chemotherapy and responses were observed in 5 (1 complete, 4 partial responses). Three elderly patients were treated with CHOP combined with thalidomide, and 2 of them achieved partial responses. One patient, failed three chemotherapy regimens, accepted thalidomide combined with etopside and achieved stable disease for 10 months. One patient with early stage had disease-free survival of 61.9 months after treatment. The other eight patients experienced recurrence or progression after the first-line chemotherapy, and 6 of them died of disease progression within 2 years after the diagnosis. Conclusion: The HIV-negative PBL patients in this study did not have an apparent association with immunosuppression. Primary extra nodal diseases were common, but only 1 patient had oral involvement. Most patients had advanced stage and poor prognosis. Effectiveness of thalidomide in the treatment of PBL deserves further investigation.

[Clinical features and prognosis of CD20-positive classical Hodgkin lymphoma]

OBJECTIVE

To explore the clinical characteristics and prognosis of CD20-positive classical Hodgkin lymphoma (CHL).

METHODS

Data from CHL patients with CD20 immunohistochemical staining result who were treated in Cancer Hospital of Chinese Academy of Medical Sciences between September 2007 and March 2014 were reviewed. The relationship of CD20 expression in Reed-Sternberg(R-S)cells with CHL subtypes, clinical characteristics, and prognosis were analyzed. Fisher test was used to analyze the differences between groups and Kaplan-Meier for survival analysis.

RESULTS

A total of 263 patients were included in this study. Among the 263 patients, 74 (28.1%) were CD20-postitive. CD20-positive cases showed significantly higher proportions of Epstein-Barr virus (EBV) infection-related, mixed cellularity, and lymphocyte-rich CHL subtypes compared with CD20-negeative patients [52.8% (28/53) vs 19.0% (22/116), 37.9% (25/66) vs 31.6% (54/171), 22.7% (15/66) vs 3.5% (6/171), all P<0.05]. Univariate analysis identified EBV infection, age (≥ 40 years, especially ≥ 60 years), and Ⅲ-Ⅳ stage were correlated with reduced 3-year progression-free survival (PFS) and overall survival (OS) (PFS: 70.3 vs 87.7%, 79.2% vs 89.8%, 56.8% vs 91.5%, 70.4% vs 93.2%; OS: 81.0% vs 100%, 92.1% vs 99.4%, 75.4% vs 99.2%, 90.3% vs 100%; all P<0.05); and CD20-positive and not receiving local radiotherapy were associated with reduced PFS (79.7% vs 90.6%, 68.8% vs 90.6%, both P<0.05), not with OS (92.4% vs 98.3%, 94.0% vs 99.4%, both P>0.05). Patients positive in both CD20 expression and EBV-encoded small RNAs (EBER) showed low PFS.

CONCLUSIONS

CD20 expression in R-S cells in CHL may be closed related with EBV infection. EBV infection is associated with unfavorable prognosis. The effect of CD20-postitive on prognosis may be mediated by the prognostic effect of EBV infection.

The application of clinical pathways in laparoscopic cholecystectomy

BACKGROUND

Laparoscopic cholecystectomy (LC) is one of the most frequent abdominal surgical procedures. The present meta-analysis aimed to estimate the clinical effects of implementing a clinical pathway for LC compared with standard medical care by evaluating the length of hospital stay, costs, and the outcomes of patients undergoing LC.

DATA SOURCES

Data were extracted from the following databases: PubMed, EMBASE, the Cochrane Central Register of Controlled Trials, Chinese Medical Citation Index (CMCI), Chinese Medical Current Contents (CMCC), and China BioMedical Literature Database (CBM). We also searched the reference lists of the relevant articles and conference articles. Only randomized controlled trials and controlled clinical trials published from 1980 to 2013 were included. We did not set restrictions on language and country of publications. All of the data were evaluated and analyzed by two reviewers independently with RevMan software (version 5.0).

RESULTS

A total of 7 trials with 1187 patients were included. The patients who underwent LC with clinical pathway had shorter hospital stay [weighted mean difference=-1.90, 95% CI: -2.65 to -1.16, P<0.00001], lower cost [standard mean difference=-0.69, 95% CI: -0.82 to -0.56, P<0.00001], and better questionnaires based satisfaction with the medical services.

CONCLUSIONS

The applications of the clinical pathway for LC effectively reduced hospital stay and total costs. However, there was insufficient evidence for proving the differences in postoperative complications. Future research should focus on patient outcomes and identify the mechanisms underlying the effect of the clinical pathway.

Glass-like recovery of antiferromagnetic spin ordering in a photo-excited manganite Pr₀.₇Ca₀.₃MnO₃

Electronic orderings of charges, orbitals and spins are observed in many strongly correlated electron materials, and revealing their dynamics is a critical step toward undertsanding the underlying physics of important emergent phenomena. Here we use time-resolved resonant soft x-ray scattering spectroscopy to probe the dynamics of antiferromagnetic spin ordering in the manganite Pr₀.₇Ca₀.₃MnO₃ following ultrafast photo-exitation. Our studies reveal a glass-like recovery of the spin ordering and a crossover in the dimensionality of the restoring interaction from quasi-1D at low pump fluence to 3D at high pump fluence. This behavior arises from the metastable state created by photo-excitation, a state characterized by spin disordered metallic droplets within the larger charge- and spin-ordered insulating domains. Comparison with time-resolved resistivity measurements suggests that the collapse of spin ordering is correlated with the insulator-to-metal transition, but the recovery of the insulating phase does not depend on the re-establishment of the spin ordering.

Characterization of microsatellite loci in the lesser dawn bat (Eonycteris spelaea)

We constructed a genomic DNA library enriched for CA repeat motifs in Eonycteris spelaea. Nine microsatellite loci were isolated and tested on a population of 39 samples from Yunnan Province, China. These nine loci had three to 22 alleles per locus. Observed and expected heterozygosity values ranged from 0.079 to 0.963 and from 0.078 to 0.959. Two loci revealed significant departure from Hardy-Weinberg equilibrium and no linkage disequilibrium was found between loci pairs. These microsatellites can be a powerful molecular tool for population-level studies of E. spelaea.

Real-time manifestation of strongly coupled spin and charge order parameters in stripe-ordered La(1.75)Sr(0.25)NiO(4) nickelate crystals using time-resolved resonant x-ray diffraction

We investigate the order parameter dynamics of the stripe-ordered nickelate, La(1.75)Sr(0.25)NiO(4), using time-resolved resonant x-ray diffraction. In spite of distinct spin and charge energy scales, the two order parameters' amplitude dynamics are found to be linked together due to strong coupling. Additionally, the vector nature of the spin sector introduces a longer reorientation time scale which is absent in the charge sector. These findings demonstrate that the correlation linking the symmetry-broken states does not unbind during the nonequilibrium process, and the time scales are not necessarily associated with the characteristic energy scales of individual degrees of freedom.

Meta-analysis of robotic and laparoscopic surgery for treatment of rectal cancer

AIM: To conduct a meta-analysis to determine the relative merits of robotic surgery (RS) and laparoscopic surgery (LS) for rectal cancer.

METHODS: A literature search was performed to identify comparative studies reporting perioperative outcomes for RS and LS for rectal cancer. Pooled odds ratios and weighted mean differences (WMDs) with 95% confidence intervals (95% CIs) were calculated using either the fixed effects model or random effects model.

RESULTS: Eight studies matched the selection criteria and reported on 661 subjects, of whom 268 underwent RS and 393 underwent LS for rectal cancer. Compared the perioperative outcomes of RS with LS, reports of RS indicated favorable outcomes considering conversion (WMD: 0.25; 95% CI: 0.11-0.58; P = 0.001). Meanwhile, operative time (WMD: 27.92, 95% CI: -13.43 to 69.27; P = 0.19); blood loss (WMD: -32.35, 95% CI: -86.19 to 21.50; P = 0.24); days to passing flatus (WMD: -0.18, 95% CI: -0.96 to 0.60; P = 0.65); length of stay (WMD: -0.04; 95% CI: -2.28 to 2.20; P = 0.97); complications (WMD: 1.05; 95% CI: 0.71-1.55; P = 0.82) and pathological details, including lymph nodes harvested (WMD: 0.41, 95% CI: -0.67 to 1.50; P = 0.46), distal resection margin (WMD: -0.35, 95% CI: -1.27 to 0.58; P = 0.46), and positive circumferential resection margin (WMD: 0.54, 95% CI: 0.12-2.39; P = 0.42) were similar between RS and LS.

CONCLUSION: RS for rectal cancer is superior to LS in terms of conversion. RS may be an alternative treatment for rectal cancer. Further studies are required.

Ferromagnetic enhancement of CE-type spin ordering in (Pr,Ca)MnO3

We present resonant soft x-ray scattering results from small bandwidth manganites (Pr,Ca)MnO(3), which show that the CE-type spin ordering (SO) at the phase boundary is stabilized only below the canted antiferromagnetic transition temperature and enhanced by ferromagnetism in the macroscopically insulating state (FM-I). Our results reveal the fragility of the CE-type ordering that underpins the colossal magnetoresistance effect in this system, as well as an unexpected cooperative interplay between FM-I and CE-type SO which is in contrast to the competitive interplay between the ferromagnetic metallic state and CE-type ordering.

Quantum criticality and nodal superconductivity in the FeAs-based superconductor KFe2As2

The in-plane resistivity rho and thermal conductivity kappa of the FeAs-based superconductor KFe2As2 single crystal were measured down to 50 mK. We observe non-Fermi-liquid behavior rho(T) approximately T{1.5} at H{c{2}}=5 T, and the development of a Fermi liquid state with rho(T) approximately T{2} when further increasing the field. This suggests a field-induced quantum critical point, occurring at the superconducting upper critical field H{c{2}}. In zero field, there is a large residual linear term kappa{0}/T, and the field dependence of kappa_{0}/T mimics that in d-wave cuprate superconductors. This indicates that the superconducting gaps in KFe2As2 have nodes, likely d-wave symmetry. Such a nodal superconductivity is attributed to the antiferromagnetic spin fluctuations near the quantum critical point.

Etoposide 1.0 g/m2 or 1.5 g/m2 combined with granulocyte colony-stimulating factor for mobilization of peripheral blood stem cells in patients with malignancy: efficacy and toxicity

BACKGROUND

The purpose of this study was to observe the efficacy and toxicity of etoposide at two dose levels for peripheral blood stem cell (PBSC) mobilization and disease debulking in patients with malignancy. Simultaneously, factors affecting the yield of CD34+ cells were explored.

METHODS

Thirty-eight patients received etoposide 1.0 g/m2 (group A) or 1.5 g/m2 (group B) followed by granulocyte colony-stimulating factor (G-CSF) 300 microg/day for PBSC mobilization in a non-randomized manner. Each group had 19 patients.

RESULTS

The median number of CD34+ cells collected was 17.33 x 10(6)/kg (range 4.85-89.00 x 10(6)/kg) in group A and 26.54 x 10(6)/kg (range 1.85-108.00 x 10(6)/kg) in group B. Altogether, 34/38 (89.5%) patients obtained the target total collection of at least 4 x 10(6) CD34+ cells/kg by a single leukapheresis. Vomiting was the most common grade 3/4 non-hematologic toxicity. For 19 evaluable patients, partial response was achieved in four (21.1%), stable disease in 11 (57.8%) and progressive disease in four (21.1%) patients. All parameters between the two groups did not reach a significant level. With multivariate analysis, the most predictive factor for CD34+ yield of the first leukapheresis was the percentage of CD34+ CD38(-) cells in peripheral blood.

CONCLUSION

These results indicate that etoposide combined with G-CSF is an effective and tolerable regimen for PBSC mobilization, given at a dose of either 1.0 g/m2 or 1.5 g/m2.

Metal to insulator transition in epitaxial graphene induced by molecular doping

The capability to control the type and amount of charge carriers in a material and, in the extreme case, the transition from metal to insulator, is one of the key challenges of modern electronics. By employing angle-resolved photoemission spectroscopy we find that a reversible metal to insulator transition and a fine-tuning of the charge carriers from electrons to holes can be achieved in epitaxial bilayer and single layer graphene by molecular doping. The effects of electron screening and disorder are also discussed. These results demonstrate that epitaxial graphene is suitable for electronics applications, as well as provide new opportunities for studying the hole doping regime of the Dirac cone in graphene.

NS-398 enhances the efficacy of gemcitabine against lung adenocarcinoma through up-regulation of p21WAF1 and p27KIP1 protein

Gemcitabine is a chemotherapeutic drug widely used in the treatment of non-small cell lung carcinoma, especially in advanced lung adenocarcinoma. However, many patients with advanced lung adenocarcinoma show a resistance to gemcitabine. Overexpression of COX-2 has been found in human non-small cell lung cancer tissues and itA s cell lines. Evidences show that COX-2 is involved in drug resistance of tumor. However, It is unknown whether COX-2 inhibitor can augment the efficacy of gemcitabine against lung adenocarcinoma. In this study, A549 cells were treated with gemcitabine and/or NS-398. The cell viability was examined by MTT assay. The cell cycle distribution and apoptotic ratio were tested by flow cytometry. The levels of p21WAF1, p27KIP1, p16INK4a and p15INK4b expression were detected by western blotting. After the cells were treated with gemcitabine along with NS-398, more cells were arrested in G1 phase and went to apoptosis. The levels of p21WAF1 and p27KIP1 protein were elevated, while the levels of p16INK4a and p15INK4b protein were not changed. It can be concluded that NS-398 enhances the efficacy of gemcitabine against lung adenocarcinoma and the efficacy is associated with up-regulation of p21WAF1 and p27KIP1protein.

Substrate-induced bandgap opening in epitaxial graphene

Graphene has shown great application potential as the host material for next-generation electronic devices. However, despite its intriguing properties, one of the biggest hurdles for graphene to be useful as an electronic material is the lack of an energy gap in its electronic spectra. This, for example, prevents the use of graphene in making transistors. Although several proposals have been made to open a gap in graphene's electronic spectra, they all require complex engineering of the graphene layer. Here, we show that when graphene is epitaxially grown on SiC substrate, a gap of approximately 0.26 eV is produced. This gap decreases as the sample thickness increases and eventually approaches zero when the number of layers exceeds four. We propose that the origin of this gap is the breaking of sublattice symmetry owing to the graphene-substrate interaction. We believe that our results highlight a promising direction for bandgap engineering of graphene.

Revealing charge density wave formation in the LaTe2 system by angle resolved photoemission spectroscopy

We present the first direct study of charge density wave (CDW) formation in quasi-2D single layer LaTe2 using high-resolution angle resolved photoemission spectroscopy and low energy electron diffraction. CDW formation is driven by Fermi surface (FS) nesting, however, characterized by a surprisingly smaller gap ( approximately 50 meV) than seen in the double layer RTe2 compounds, extending over the entire FS. This establishes LaTe2 as the first reported semiconducting 2D CDW system where the CDW phase is FS nesting driven. In addition, the layer dependence of this phase in the tellurides and the possible transition from a stripe to a checkerboard phase is discussed.

Universal high energy anomaly in the angle-resolved photoemission spectra of high temperature superconductors: possible evidence of spinon and holon branches

A universal high energy anomaly in the single particle spectral function is reported in three different families of high temperature superconductors by using angle-resolved photoemission spectroscopy. As we follow the dispersing peak of the spectral function from the Fermi energy to the valence band complex, we find dispersion anomalies marked by two distinctive high energy scales, E1 approximately 0.38 eV and E2 approximately 0.8 eV. E1 marks the energy above which the dispersion splits into two branches. One is a continuation of the near parabolic dispersion, albeit with reduced spectral weight, and reaches the bottom of the band at the Gamma point at approximately 0.5 eV. The other is given by a peak in the momentum space, nearly independent of energy between E1 and E2. Above E2, a bandlike dispersion reemerges. We conjecture that these two energies mark the disintegration of the low-energy quasiparticles into a spinon and holon branch in the high Tc cuprates.

Strong and complex electron-lattice correlation in optimally doped Bi2Sr2CaCu2O8+delta

We discuss the nature of electron-lattice interaction in optimally doped Bi_{2}Sr_{2}CaCu_{2}O_{8+delta} samples, using the isotope effect (IE) in angle resolved photoemission spectroscopy (ARPES) data. The IE in the ARPES linewidth and the IE in the ARPES dispersion are both quite large, implying a strong electron-lattice correlation. The strength of the electron-lattice interaction is "intermediate," i.e., stronger than the Migdal-Eliashberg regime but weaker than the small polaron regime, requiring a more general picture of the ARPES kink than the commonly used Migdal-Eliashberg picture. The two IEs also imply a complex interaction, due to their strong momentum dependence and their differing sign behaviors. In sum, we propose an intermediate-strength coupling of electrons to localized lattice vibrations via charge density fluctuations.

Elastic scattering susceptibility of the high temperature superconductor Bi2Sr2CaCu2O(8+delta): a comparison between real and momentum space photoemission spectroscopies

The joint density of states of Bi2Sr2CaCu2O(8+delta) is calculated by evaluating the autocorrelation of the single particle spectral function A(k, omega) measured from angle resolved photoemission spectroscopy (ARPES). These results are compared with Fourier transformed (FT) conductance modulations measured by scanning tunneling microscopy (STM). Good agreement between the two experimental probes is found for two different doping values examined. In addition, by comparing the FT-STM results to the autocorrelated ARPES spectra with different photon polarization, new insight on the form of the STM matrix elements is obtained. This shines new light on unsolved mysteries in the tunneling data.

Morphological brain changes associated with Schneider's first-rank symptoms in schizophrenia: a MRI study

BACKGROUND

Schneider's first-rank symptoms involve an alienated feature of the sense of one's own mental or physical activity. To clarify the brain morphological basis for the production of these symptoms, volumes of the frontal and medial temporal regions and their clinical correlates were examined in patients with schizophrenia.

METHOD

Twenty-two patients with schizophrenia and 44 age- and gender-matched healthy control subjects were included. All patients were in their psychotic episodes with definite Schneiderian symptoms, rated by using the Scale for Assessment of Positive Symptoms. Volumetric measurements of high-resolution magnetic resonance imaging were performed in the prefrontal area, cingulate gyrus, and precentral gyrus, and the medial temporal structures such as the amygdala, hippocampus, and parahippocampal gyrus.

RESULTS

Patients had significantly decreased volumes in the cingulate gray matter and the amygdala compared to controls. In the patient group, Schneiderian symptom severity showed significant inverse correlations with volumes of the right posterior cingulate gray matter and of the left anterior parahippocampal gyrus.

CONCLUSIONS

Schneiderian symptoms may be associated with morphological abnormalities in the limbic-paralimbic regions such as the cingulate gyrus and parahippocampal gyrus, which possibly serve the self-monitoring function and the coherent storage and reactivation of information.

An unusual isotope effect in a high-transition-temperature superconductor

In conventional superconductors, the electron pairing that allows superconductivity is caused by exchange of virtual phonons, which are quanta of lattice vibration. For high-transition-temperature (high-T(c)) superconductors, it is far from clear that phonons are involved in the pairing at all. For example, the negligible change in T(c) of optimally doped Bi2Sr2CaCu2O8+delta (Bi2212; ref. 1) upon oxygen isotope substitution (16O --> 18O leads to T(c) decreasing from 92 to 91 K) has often been taken to mean that phonons play an insignificant role in this material. Here we provide a detailed comparison of the electron dynamics of Bi2212 samples containing different oxygen isotopes, using angle-resolved photoemission spectroscopy. Our data show definite and strong isotope effects. Surprisingly, the effects mainly appear in broad high-energy humps, commonly referred to as 'incoherent peaks'. As a function of temperature and electron momentum, the magnitude of the isotope effect closely correlates with the superconducting gap--that is, the pair binding energy. We suggest that these results can be explained in a dynamic spin-Peierls picture, where the singlet pairing of electrons and the electron-lattice coupling mutually enhance each other.

Complete genome analysis of the mandarin fish infectious spleen and kidney necrosis iridovirus

The nucleotide sequence of the infectious spleen and kidney necrosis virus (ISKNV) genome was determined and found to comprise 111,362 bp with a G+C content of 54.78%. It contained 124 potential open reading frames (ORFs) with coding capacities ranging from 40 to 1208 amino acids. The analysis of the amino acid sequences deduced from the individual ORFs revealed that 35 of the 124 potential gene products of ISKNV show significant homology to functionally characterized proteins of other species. Some of the putative gene products of ISKNV showed significant homologies to proteins in the GenBank/EMBL/DDBJ databases including enzymes and structural proteins involved in virus replication, transcription, protein modification, and virus-host interaction. In addition, one major repeated sequence showing significant homology to the Red Sea bream iridovirus (RSIV) genome was identified. Based on the information obtained from biological properties (including histopathology, tissue tropisms, natural host range, and geographic distribution), physiochemical and physical properties, and genome analysis, we suggest that ISKNV, RSIV, sea bass iridovirus, grouper iridovirus, and African lampeye iridovirus may belong to a new genus of the Iridoviridae family and are tentatively referred to as cell hypertrophy iridoviruses.

Serotonin(2) receptors mediate respiratory recovery after cervical spinal cord hemisection in adult rats

The aim of the present study was to specifically investigate the involvement of serotonin [5-hydroxytryptamine (5-HT(2))] receptors in 5-HT-mediated respiratory recovery after cervical hemisection. Experiments were conducted on C(2) spinal cord-hemisected, anesthetized (chloral hydrate, 400 mg/kg ip), vagotomized, pancuronium- paralyzed, and artificially ventilated female Sprague-Dawley rats in which CO(2) levels were monitored and maintained. Twenty-four hours after spinal hemisection, the ipsilateral phrenic nerve displayed no respiratory-related activity indicative of a functionally complete hemisection. Intravenous administration of the 5-HT(2A/2C)-receptor agonist (+/-)-2,5-dimethoxy-4-iodoamphetamine hydrochloride (DOI) induced respiratory-related activity in the phrenic nerve ipsilateral to hemisection under conditions in which CO(2) was maintained at constant levels and augmented the activity induced under conditions of hypercapnia. The effects of DOI were found to be dose dependent, and the recovery of activity could be maintained for up to 2 h after a single injection. DOI-induced recovery was attenuated by the 5-HT(2)-receptor antagonist ketanserin but not with the 5-HT(2C)-receptor antagonist RS-102221, suggesting that 5-HT(2A) and not necessarily 5-HT(2C) receptors may be involved in the induction of respiratory recovery after cervical spinal cord injury.

Activation of a latent respiratory motor pathway by stimulation of neurons in the medullary chemoreceptor area of the rat

Previous studies have demonstrated that during respiratory stress (hypercapnia and hypoxia), a latent crossed respiratory pathway can be activated to produce hemidiaphragm recovery following an ipsilateral C2 spinal cord hemisection. The present study investigates the effects of ventral medullary chemoreceptor area stimulation by microinjection of (1S,3R)-aminocyclopentanedicarboxylic acid (ACPD), a glutamate metabotropic receptor agonist, on activating the latent pathway following left C2 spinal cord hemisection in rats in which end-tidal CO2 was maintained at a constant level. Experiments were conducted on anesthetized, vagotomized, paralyzed, and artificially ventilated rats in which phrenic nerve activity was recorded bilaterally. Before drug injection, the phrenic nerve contralateral to hemisection showed vigorous respiratory-related activity, but the phrenic nerve ipsilateral to hemisection showed no discernible respiratory-related activity. ACPD (1-100 nl, 1 mM) was injected directly into the region of the retrotrapezoid nucleus (RTN), a known medullary chemoreceptor area. Microinjection of ACPD into the right RTN increased respiratory-related activity in the right phrenic nerve (contralateral to hemisection). ACPD (>5 nl, 1 mM) microinjection also significantly induced respiratory recovery in the phrenic nerve ipsilateral to hemisection in a dose-dependent manner. The present study indicates that respiratory recovery can be achieved by stimulation of respiratory circuitry without increasing CO2 levels.

Delivery of glucocorticoid conjugate in rat gastrointestinal tract and its treatment for ulcerative colitis

AIM

To evaluate colonic delivery and therapeutic effect of the newly synthesized dexamethasone (DX)-dextran (500 000) conjugate (DXD50) in the rat.

METHODS

The amount of dexamethasone was measured in the contents from different parts of rat gastrointestinal tract and in plasma after ig conjugate. Therapeutic effect of conjugate and DX was tested in trinitrobenzenesulfonic acid-induced colitis in rat. Repair of colitis was assessed by measuring colonic ulceration area, colon weight, and colonic myeloperoxidase (MPO) activity. Systemic immunosuppression of DX was evaluated with weight of thymus and spleen and lymphocyte count in peripheral blood from rat with ulcerative colitis.

RESULTS

Dexamethasone released from conjugate was mainly distributed in contents of cecum and colon. When DXD50 and DX 0.25 micromol . kg-1 . d-1 were used ig to treat ulcerative colitis in rat, the ulcerative area of colon was reduced by 55.6 % and 33.3 %, respectively whereas colon weight was reduced by 17.9 % and 2.6 %, respectively. The conjugate had no effect on lymphocyte count in peripheral blood, spleen weight, and thymus weight of rat which could be reduced markedly by the same dose of DX (P < 0.05 vs control).

CONCLUSION

DXD50, which could specifically deliver DX to large intestine, is a promising agent in the treatment of human inflammatory bowel disease.

Distribution of Serotonin 2A and 2C Receptor mRNA Expression in the Cervical Ventral Horn and Phrenic Motoneurons Following Spinal Cord Hemisection

Cervical spinal cord injury leads to a disruption of bulbospinal innervation from medullary respiratory centers to phrenic motoneurons. Animal models utilizing cervical hemisection result in inhibition of ipsilateral phrenic nerve activity, leading to paralysis of the hemidiaphragm. We have previously demonstrated a role for serotonin (5-HT) as one potential modulator of respiratory recovery following cervical hemisection, a mechanism that likely occurs via 5-HT2A and/or 5-HT2C receptors. The present study was designed to specifically examine if 5-HT2A and/or 5-HT2C receptors are colocalized with phrenic motoneurons in both intact and spinal-hemisected rats. Adult female rats (250-350 g; n = 6 per group) received a left cervical (C2) hemisection and were injected with the fluorescent retrograde neuronal tracer Fluorogold into the left hemidiaphragm. Twenty-four hours later, animals were killed and spinal cords processed for in situ hybridization and immunohistochemistry. Using (35)S-labeled cRNA probes, cervical spinal cords were probed for 5-HT2A and 5-HT2C receptor mRNA expression and double-labeled using an antibody to Fluorogold to detect phrenic motoneurons. Expression of both 5-HT2A and 5-HT2C receptor mRNA was detected in motoneurons of the cervical ventral horn. Despite positive expression of both 5-HT2A and 5-HT2C receptor mRNA-hybridization signal over phrenic motoneurons, only 5-HT2A silver grains achieved a signal-to-noise ratio representative of colocalization. 5-HT2A mRNA levels in identified phrenic motoneurons were not significantly altered following cervical hemisection compared to sham-operated controls. Selective colocalization of 5-HT2A receptor mRNA with phrenic motoneurons may have implications for recently observed 5-HT2A receptor-mediated regulation of respiratory activity and/or recovery in both intact and injury-compromised states.

[Pharmacokinetics of site-specific delivery of dexamethasone-dextran prodrug in rat gastrointestinal tract]

AIM

To explore whether dexamethasone-dextran (260,000) has the characteristics of site-specific delivery in rat gastrointestinal tract.

METHODS

Dexamethasone prodrug and dexamethasone were administered to rat ig at the dose of 5 mumol.kg-1. The distribution of dexamethasone in the contents and mucosa of different parts of the rat GI tract at different time intervals and its concentration in plasma were determined by HPLC.

RESULTS

Dexamethasone was mainly released in the cecum and colon contents and mucosa after oral administration of dexamethasone prodrug. The absorption was reduced significantly. The peak time of the drug in plasma was 8.1 h, and the peak concentration was 32 micrograms.L-1. However, free dexamethasone was found mainly in the contents and mucosa of the stomach, proximal and distal small intestine. The peak time of the drug in plasma was 2.2 h, and the peak concentration was 2120 micrograms.L-1.

CONCLUSION

Dexamethasone can be specifically delivered to the large intestine by using dexamethasone-dextran (260,000). It appears that the prodrug has a potential in the treatment of inflammatory bowel disease.