[Neoadjuvant strategy for locally advanced colorectal cancer based organ preservation]

Neoadjuvant therapy for locally advanced colorectal cancer has made great progress in the past 20 years, but there are still limitations such as side effects, organ dysfunction and unsatisfactory control of metastasis. In recent years, with the improvement of surgical techniques and further development of molecular research, how to further improve local control, reduce distant metastasis, and even avoid surgery according to clinical remission to achieve organ preservation, is the current demand and research goal. With the advancement of molecular research, colorectal cancer has different treatment strategies based on microsatellite status. For patients with microsatellite instability locally advanced colorectal cancer, immune checkpoint inhibitor therapy significantly increased the pathologic complete response rate, reduced the incidence of adverse events and improved organ function compared with conventional chemoradiotherapy. For patients with microsatellite stable locally advanced colon cancer, neoadjuvant therapy is still in the exploratory stage. The standard of care is surgery combined with perioperative chemotherapy. For microsatellite stable locally advanced rectal cancer, the complete response rate is improved by enhancing neoadjuvant therapy, which helps to preserve organs. On the other hand, selective radiotherapy preserves organ function and improves quality of life. This article reviews the neoadjuvant treatment strategies for locally advanced colorectal cancer based on organ-sparing strategies.

[Pathogenic mechanisms of impaired neuronal autophagy flux after ischemic stroke]

Autophagy is a metabolic process in which damaged organelles, obsolete proteins, excess cytoplasmic components, and even pathogens are presented to lysosomes for degradation via autophagosomes. It includes 4 processes: the initiation of autophagy, the formation of autophagosomes, the fusion of autophagosomes with lysosomes, and the degradation and removal of autophagic substrates within autophagic lysosomes. When these processes are continuous, it is called autophagy flux. Blockage of one or certain steps in the autophagy/lysosome signaling pathway can lead to impaired autophagy flux. Numerous studies have shown that impaired autophagy flux is an important cause of neuronal damage in the ischemic penumbra after stroke. This paper summarized research progress in the pathological mechanisms that cause impaired neuronal autophagy flux after ischemic stroke and discusses methods to improve neuronal autophagy flux, in order to provide a reference for an in-depth investigation of the pathological injury mechanisms after stroke.

Berberine Alleviates Ischemic Brain Injury by Enhancing Autophagic Flux via Facilitation of TFEB Nuclear Translocation

Berberine has been demonstrated to alleviate cerebral ischemia/reperfusion injury, but its neuroprotective mechanism has yet to be understood. Studies have indicated that ischemic neuronal damage was frequently driven by autophagic/lysosomal dysfunction, which could be restored by boosting transcription factor EB (TFEB) nuclear translocation. Therefore, this study investigated the pharmacological effects of berberine on TFEB-regulated autophagic/lysosomal signaling in neurons after cerebral stroke. A rat model of ischemic stroke and a neuronal ischemia model in HT22 cells were prepared using middle cerebral artery occlusion (MCAO) and oxygen-glucose deprivation (OGD), respectively. Berberine was pre-administered at a dose of 100[Formula: see text]mg/kg/d for three days in rats and 90[Formula: see text][Formula: see text]M in HT22 neurons for 12[Formula: see text]h. 24[Formula: see text]h after MCAO and 2[Formula: see text]h after OGD, the penumbral tissues and OGD neurons were obtained to detect nuclear and cytoplasmic TFEB, and the key proteins in the autophagic/lysosomal pathway were examined using western blot and immunofluorescence, respectively. Meanwhile, neuron survival, infarct volume, and neurological deficits were assessed to evaluate the therapeutic efficacy. The results showed that berberine prominently facilitated TFEB nuclear translocation, as indicated by increased nuclear expression in penumbral neurons as well as in OGD HT22 cells. Consequently, both autophagic activity and lysosomal capacity were simultaneously augmented to alleviate the ischemic injury. However, berberine-conferred neuroprotection could be greatly counteracted by lysosomal inhibitor Bafilomycin A1 (Baf-A1). Meanwhile, autophagy inhibitor 3-Methyladenine (3-MA) also slightly neutralized the pharmacological effect of berberine on ameliorating autophagic/lysosomal dysfunction. Our study suggests that berberine-induced neuroprotection against ischemic stroke is elicited by enhancing autophagic flux via facilitation of TFEB nuclear translocation in neurons.

[Predictive value of stress-induced hyperglycemia on 28 d risk of all-cause death in intensive care patients]

OBJECTIVE

To investigate the relationship between stress glucose elevation and the risk of 28 d all-cause mortality in intensive care unit (ICU) patients, and to compare the predictive efficacy of different stress glucose elevation indicators.

METHODS

ICU patients who met the inclusion and exclusion criteria in the Medical Information Mart for Intensive Care Ⅳ (MIMIC-Ⅳ) database were used as the study subjects, and the stress glucose elevation indicators were divided into Q1 (0-25%), Q2 (>25%- 75%), and Q3 (>75%-100%) groups, with whether death occurred in the ICU and the duration of treatment in the ICU as outcome variables, and demographic characteristics, laboratory indicators, and comorbidities as covariates, Cox regression and restricted cubic splines were used to explore the association between stress glucose elevation and the risk of 28 d all-cause death in ICU patients; and subject work characteristics [receiver operating characteristic (ROC) and the area under curve (AUC)] were used to evaluate the predictive efficacy of different stress glucose elevation indicators, The stress hyperglycemia indexes included: stress hyperglycemia ratio (SHR1, SHR2), glucose gap (GG); and the stress hyperglycemia index was further incorporated into the Oxford acute severity of illness score (OASIS) to investigate the predictive efficacy of the improved scores: the AUC was used to assess the score discrimination, and the larger the AUC indicated, the better score discrimination. The Brier score was used to evaluate the calibration of the score, and a smaller Brier score indicated a better calibration of the score.

RESULTS

A total of 5 249 ICU patients were included, of whom 7.56% occurred in ICU death. Cox regression analysis after adjusting for confounders showed that the HR (95%CI) for 28 d all-cause mortality in the ICU patients was 1.545 (1.077-2.217), 1.602 (1.142-2.249) and 1.442 (1.001-2.061) for the highest group Q3 compared with the lowest group Q1 for SHR1, SHR2 and GG, respectively, and The risk of death in the ICU patients increased progressively with increasing indicators of stressful blood glucose elevation (P_trend < 0.05). Restricted cubic spline analysis showed a linear relationship between SHR and the 28 d all-cause mortality risk (P>0.05). the AUC of SHR2 and GG was significantly higher than that of SHR1: AUC_SHR2=0.691 (95%CI: 0.661-0.720), AUC_GG=0.685 (95%CI: 0.655-0.714), and AUC_SHR1=0.680 (95%CI: 0.650-0.709), P < 0.05. The inclusion of SHR2 in the OASIS scores significantly improved the discrimination and calibration of the scores: AUC_OASIS=0.820 (95%CI: 0.791-0.848), AUC_OASIS+SHR2=0.832 (95%CI: 0.804-0.859), P < 0.05; Brier score_OASIS=0.071, Brier score_OASIS+SHR2=0.069.

CONCLUSION

Stressful glucose elevation is strongly associated with 28 d all-cause mortality risk in ICU patients and may inform clinical management and decision making in intensive care patients.

[Neoadjuvant immunotherapy in microsatellite stability or mismatch repair proficient colorectal cancer]

Immunotherapy has become an important treatment option for microsatellite instability-high (MSI-H) and mismatch repair deficient (dMMR) colorectal cancer. From late-line to first-line treatment, and even in neoadjuvant setting for early stage colorectal cancer, promising efficacy was observed with immunotherapy. In microsatellite stability (MSS) or mismatch repair proficient (pMMR) colorectal cancer, the researches of neoadjuvant immunotherapy have been conducted constantly. This paper focuses on the recent researches and progress of neoadjuvant immunotherapy for MSS or pMMR colorectal cancer. Neoadjuvant immunotherapy alone led to a good pathological response in a subset of patients. Studies of induction or consolidation immunotherapy before or after neoadjuvant chemoradiotherapy or concurrent immunotherapy during radiotherapy showed higher pathological complete remission (pCR) rates as compared to standard chemoradiotherapy. Studies on sequential dual immunotherapy after radiochemotherapy and targeted therapy combined with neoadjuvant immunotherapy are ongoing. At present, most of these are pilot studies with small sample size. More researches and long-term follow-up are needed to prove the efficacy of neoadjuvant immunotherapy in MSS or pMMR colorectal cancer.

[Application of aMAP score to assess the risk of hepatocarciongenesis in population of chronic liver disease in primary hospitals]

Objective: The aMAP score is a hepatocellular carcinoma (HCC) risk prediction model based on an international cooperative cohort, which can be applied to various liver diseases. The aim of this study is to use the aMAP score to stratify the risk of HCC in patients with chronic liver disease (combined or non-combined metabolic diseases) admitted to People's Hospital of Yudu County, Ganzhou City, Jiangxi Province, in order to guide personalized HCC screening. Methods: The demographic information, laboratory test results (platelets, albumin, and total bilirubin) and combined disease information of patients with chronic liver disease who were admitted to People's Hospital of Yudu from January 2016 to December 2020 were collected, and the aMAP score was calculated to stratify HCC risk in this population. Results: A total of 3629 cases with chronic liver disease were included in the analysis, including 3 452 (95.1%) cases with hepatitis B virus (HBV) infection, 177 (4.9%) cases with fatty liver, and 22 (0.6%) cases with HBV infection and fatty liver. There were 2 679 (73.8%) male and the median age was 44 (35, 54). In the overall population, low, medium and high risk of HCC accounted for 52.6%, 29.0%, and 18.4% respectively. In the HBV-infected population, the proportion of high risk of HCC was significantly higher than that of fatty liver (18.9% vs. 9.6%, P = 0.001). The proportion of chronic liver disease patients with combined hypertension or diabetes was significantly higher than that of those with non-combined metabolic diseases (combined hypertension: 32.3% vs. 17.9%, P < 0.001; combined diabetes: 36.5% vs. 18.1%, P < 0.001). Moreover, the proportion of high-risk population with two metabolic diseases was significantly higher than that with one and no metabolic diseases (40.9% vs. 31.8% vs. 17.7%, P < 0.001). Conclusion: The aMAP score can be used as a simple tool for HCC screening and management of chronic liver disease in primary hospitals, and it is helpful to improve the personalized follow-up management system of chronic liver disease population. Chronic liver disease patients with metabolic diseases have a higher risk of HCC, and people with high risk of HCC should be given special priority in follow-up visits, so as to improve the rate of HCC early diagnosis and reduce the mortality rate.

Enriched environment boosts the post-stroke recovery of neurological function by promoting autophagy

Autophagy is crucial for maintaining cellular homeostasis, and can be activated after ischemic stroke. It also participates in nerve injury and repair. The purpose of this study was to investigate whether an enriched environment has neuroprotective effects through affecting autophagy. A Sprague-Dawley rat model of transient ischemic stroke was prepared by occlusion of the middle cerebral artery followed by reperfusion. One week after surgery, these rats were raised in either a standard environment or an enriched environment for 4 successive weeks. The enriched environment increased Beclin-1 expression and the LC3-II/LC3-I ratio in the autophagy/lysosomal pathway in the penumbra of middle cerebral artery-occluded rats. Enriched environment-induced elevations in autophagic activity were mainly observed in neurons. Enriched environment treatment also promoted the fusion of autophagosomes with lysosomes, enhanced the lysosomal activities of lysosomal-associated membrane protein 1, cathepsin B, and cathepsin D, and reduced the expression of ubiquitin and p62. After 4 weeks of enriched environment treatment, neurological deficits and neuronal death caused by middle cerebral artery occlusion/reperfusion were significantly alleviated, and infarct volume was significantly reduced. These findings suggest that neuronal autophagy is likely the neuroprotective mechanism by which an enriched environment promotes recovery from ischemic stroke. This study was approved by the Animal Ethics Committee of the Kunming University of Science and Technology, China (approval No. 5301002013855) on March 1, 2019.

[Effect of enterostomy on analgesic pattern in patients with advanced digestive tract cancer]

Objective: To explore the effect of enterostomy on analgesic pattern in advanced digestive tract cancer. Methods: A retrospective cohort study was carried out, which was approved by the Ethics Committee of the Sixth Affiliated Hospital of Sun Yat-sen University (E2018026). Inclusion criteria were as follows: (1)age and gender were not limited; (2) all the gastrointestinal malignancies were confirmed histologically, and local recurrence or metastasis were confirmed by CT or MR; (3) numerical rating scale (NRS) ≥4 points, opioid analgesic drugs were required; (4) informed consents were signed by patients of their own. Exclusion criteria were as follows: (1) malignancies of early stage; (2) suspicious adverse mental states which might lead to poor administration compliance; (3) hypersensitivity or allergic reactions to opioids. Clinical data of patients with advanced gastrointestinal cancer receiving comprehensive treatment at the Medical Oncology Department of the Sixth Affiliated Hospital of Sun Yat-sen University from September 2016 to April 2017 were retrospectively collected. The patients were divided into the stoma group and the non-stoma group. The clinical findings of two groups were analyzed, including age, sex, ostomy status, pain location, presence or absence of intestinal obstruction, pain characteristics, selection of opioid analgesic agents, treatment of side effects of analgesics. Pain was assessed using brief pain inventory(BPI) table and NRS score. Strong opioids were prescribed for patients of NRS ≥4. Patients who were intolerant to opioids required opioid titration. The titration drugs included oral or IV morphine and oxycodone. After achievement of adequate pain control, long-acting opioids were administered, which included sustained-release morphine tablets, controlled release oxycodone and transdermal fentanyl. Criteria for pain relief included NRS≤3, breakthrough pain <3 times/day and duration of adequate pain control >3 days. The χ(2) test and the Wilcoxon signed rank sum test (nonparametric test) were used to analyze the clinical features of patients in the stoma and non-stomach groups. In order to find the factors associated with maintenance therapy and the use of laxatives, the variables were compared as well as in multivariate analysis with multiple regression models. For all the statistical tests, a value of P<0.05 in a two-tailed test was established as the alpha significance level. Result: A total of 123 patients were enrolled in this study, including 79 males (64.2%) and 44 females (35.8%) with a median age of 51 years. Fifty-two patients were in stoma group, including 30 (24.4%) of ileostomy and 22 (17.9%) of colostomy, and 71 patients were in non-stoma group. Pain of 40 (76.9%) patients in stoma group located in abdomenopelvic site while the pain of 44 (62.0%) patients in non-stoma group located in other sites. Compared with non-stoma group, cases in stoma group complained more abdominopelvic pain (73% vs. 62.0%, P<0.001).The median NRS pain score before treatment in the stoma group and the non-stoma group was 5.7 and 5.6, respectively, without statistically significant difference (P=0.741). After analgesic management, the above scores reduced to 2.1 and 2.3, respectively, without statistically significant difference as well (P=0.092). Analgesic treatment was effective in 111 cases (90.2%), including 49 cases (94.2%) in the stoma group, and 62 cases (87.3%) in the non-stoma group, and there was no statistically significant difference between the two groups (P=0.202). There was more application of fentanyl transdermal patch [34.6%(18/52) vs. 9.8%(7/71)] in the stoma group, while more application of lactulose laxative [78.9%(56/71) vs. 61.5%(32/52)](χ(2)=10.023, P=0.002) in the non-stoma group. Multivariate analysis revealed that ostomy (OR=0.290, 95%CI: 0.102-0.824, P=0.009) and pain site (OR=5.691, 95%CI:1.709-18.948, P=0.005) were independent factors affecting the choice of the first line opioid sustained release agent. Of the 123 patients with maintaining analgesia, 98 had available data of laxative use, of whom 46 used laxatives to prevent or treat constipation, and the proportion of laxatives in stoma group (21.2%, 11/52) was significantly lower than that in non-stoma group (49.3%, 35/71) (χ(2)=6.957, P=0.008). Multivariate analysis of the application of laxative use showed that age (OR=0.281, 95% CI: 0.123-0.684, P=0.010) and ostomy (OR=2.621, 95% CI: 1.033-6.687, P=0.045) were independent factors affecting the use of lactulose laxatives. Conclusions: Enterostomy may affect the analgesic pattern in advanced digestive tract cancer. Patients with stoma are more likely to use fentanyl transdermal patches and younger patients with stoma do not need prophylactic use of laxatives.

[Clinical application of endoscope combined with microscope for the microvascular decompression in hemifacial spasm]

Objective: To evaluate the effectiveness and safety of the endoscope combined with microscope for the microvascular decompression in hemifacial spasm. Methods: A total of 26 patients underwent endoscope combined with microscopic facial nerve microvascular decompression through retrolabyrinthine approach from January 2013 to December 2016 were retrospectively reviewed in Ear Institute, Shanghai Jiaotong University School of Medicine. Among them, 9 were male and 17 were female, with a mean age of (51.9±11.4) years;15 cases of left side and 11 of right side patients were followed up for 1-3 years. The pre-and post-operative Cohen Classification was used for hemifacial spasm, House-Brackmann Grade for facial nerve function, hearing level and complication rates were reviewed. SPSS 19.0 software was used to analyze the data. Results: All 26 patients were operated successfully. No recurrence was seen during 1-3 year follow-up. Post-operative Cohen Grade were as follows: 25 cases with Cohen Grade I and 1 case with Cohen Grade II. The difference in Cohen grade between pre-and post-operative was statistically significant (Z=-4.87, P<0.01). Post-operative facial nerve function was satisfactory in all patients (House-Brackmann Grade I-II in all patients). No hearing loss was observed. No facial paralysis and other lower cranial nerve dysfunction were observed. No postoperative complications such as cerebrospinal fluid leakage occurred. Conclusions: Using an angled endoscope combined with microscope in microvascular decompression in hemifacial spasmis is safe and effective.

Neuronal autophagy aggravates microglial inflammatory injury by downregulating CX3CL1/fractalkine after ischemic stroke

Ischemic stroke often induces excessive neuronal autophagy, resulting in brain damage; meanwhile, inflammatory responses stimulated by ischemia exacerbate neural injury. However, interactions between neuronal autophagy and microglial inflammation following ischemic stroke are poorly understood. CX3CL1/fractalkine, a membrane-bound chemokine expressed on neurons, can suppress microglial inflammation by binding to its receptor CX3CR1 on microglia. In the present study, to investigate whether autophagy could alter CX3CL1 expression on neurons and consequently change microglial inflammatory activity, middle cerebral artery occlusion (MCAO) was established in Sprague-Dawley rats to model ischemic stroke, and tissues from the ischemic penumbra were obtained to evaluate autophagy level and microglial inflammatory activity. MCAO rats were administered 3-methyladenine (autophagy inhibitor) or Tat-Beclin 1 (autophagy inducer). Western blot assays were conducted to quantify expression of Beclin-1, nuclear factor kappa B p65 (NF-κB), light chain 3B (LC3B), and CX3CL1 in ischemic penumbra. Moreover, immunofluorescence staining was performed to quantify numbers of LC3B-, CX3CL1-, and Iba-1-positive cells in ischemic penumbra. In addition, enzyme linked immunosorbent assays were utilized to analyze concentrations of tumor necrosis factor alpha (TNF-α), interleukin 6 (IL-6), interleukin 1 beta (IL-1β), and prostaglandin E2 (PGE2). A dry/wet weight method was used to detect brain water content, while 2,3,5,-triphenyltetrazolium chloride staining was utilized to measure infarct volume. The results demonstrated that autophagy signaling (Beclin-1 and LC3B expression) in penumbra was prominently activated by MCAO, while CX3CL1 expression on autophagic neurons was significantly reduced and microglial inflammation was markedly activated. However, after inhibition of autophagy signaling with 3-methyladenine, CX3CL1 expression on neurons was obviously increased, whereas Iba-1 and NF-κB expression was downregulated; TNF-α, IL-6, IL-1β, and PGE2 levels were decreased; and cerebral edema was obviously mitigated. In contrast, after treatment with the autophagy inducer Tat-Beclin 1, CX3CL1 expression on neurons was further reduced; Iba-1 and NF-κB expression was increased; TNF-α, IL-6, IL-1β, and PGE2 levels were enhanced; and cerebral edema was aggravated. Our study suggests that ischemia-induced neuronal autophagy facilitates microglial inflammatory injury after ischemic stroke, and the efficacy of this process may be associated with downregulated CX3CL1 expression on autophagic neurons.

[Phenotypic and genotypic features of twenty children with classic pantothenate kinase-associated neurodegeneration]

Objective: To explore the phenotypic and genotypic characteristics in Chinese children with classic pantothenate kinase-associated neurodegeneration (PKAN). Method: The clinical, radiographic and genetic data of all PKAN patients diagnosed at pediatric department of Peking University First Hospital from November 2006 to December 2016 were retrospectively collected and analyzed. Result: Twenty patients with classic PKAN were included in the study. The median age at onset was 3.5 years (ranging from 1.0 to 10.0 years), and the most common initial symptom was gait disturbance (16 cases). At the last evaluation, the clinical features were limbs dystonia (20 cases), dysarthria (16 cases), dysphagia (11 cases), pyramidal sign (7 cases), mental regression (3 cases) and pigmentary retinopathy (5 cases). For those classic PKAN patients, the median time from onset of disease to loss of independent ambulation was 6.9 years (ranging from 2.0 to 12.0 years). Imaging data showed, except "eye of tiger" in MRI (19 cases), globus pallidus calcification in CT was also found in four patients. In gene testing, 26 different mutations in PANK2 gene were identified, and 16 of 26 were novel mutations. Moreover, c. 1502T>C (p.Ile501Asn) was the most common mutation (4 cases). Conclusion: Dystonia is the major neurologic feature of classic PKAN. Disease progression is rapid, with loss of independent ambulation within 10 years after onset. Except "eye of tiger" in MRI, globus pallidus calcification in CT may be another imaging feature of PKAN.Sixteen novel mutations of PANK2 gene were identified in the study.

Eculizumab Therapy for Chronic Antibody-Mediated Injury in Kidney Transplant Recipients: A Pilot Randomized Controlled Trial

We hypothesized that de novo donor-specific antibody (DSA) causes complement-dependent endothelial cell injury in kidney transplants, as assessed by expression of endothelial cell-associated transcripts (ENDATs), that may be attenuated through complement inhibition. In total, 15 participants (five control, 10 treatment) with DSA and deteriorating renal function were enrolled. The treatment group received 6 mo of eculizumab followed by 6 mo of observation, whereas controls were observed. The primary end point was percentage change in estimated GFR (eGFR) trajectory over the treatment period. The treatment group had an improved eGFR trajectory versus control, based on our predetermined two-sided 0.10 significance level (p = 0.09). Within-subject analysis of treated participants at 6-mo intervals did not show significant change (p = 0.60). Modeling C1q status showed that C1q-positive patients had significantly higher mean eGFR than patients with negative C1q (p = 0.04). Biopsies revealed elevated renal ENDATs in most participants, but ENDATs were not reduced with complement inhibition. Our data suggest that eculizumab treatment may stabilize kidney function in patients with chronic persistent DSA based on our pilot a priori significance threshold. ENDAT expression predicative of acute humoral injury is not reduced with complement inhibition in this chronic setting. Further studies will be necessary to determine which patients may benefit from eculizumab.

Dynamic changes in neuronal autophagy and apoptosis in the ischemic penumbra following permanent ischemic stroke

The temporal dynamics of neuronal autophagy and apoptosis in the ischemic penumbra following stroke remains unclear. Therefore, in this study, we investigated the dynamic changes in autophagy and apoptosis in the penumbra to provide insight into potential therapeutic targets for stroke. An adult Sprague-Dawley rat model of permanent ischemic stroke was prepared by middle cerebral artery occlusion. Neuronal autophagy and apoptosis in the penumbra post-ischemia were evaluated by western blot assay and immunofluorescence staining with antibodies against LC3-II and cleaved caspase-3, respectively. Levels of both LC3-II and cleaved caspase-3 in the penumbra gradually increased within 5 hours post-ischemia. Thereafter, levels of both proteins declined, especially LC3-II. The cerebral infarct volume increased slowly 1–4 hours after ischemia, but subsequently increased rapidly until 5 hours after ischemia. The severity of the neurological deficit was positively correlated with infarct volume. LC3-II and cleaved caspase-3 levels were high in the penumbra within 5 hours after ischemia, and after that, levels of these proteins decreased at different rates. LC3-II levels were reduced to a very low level, but cleaved caspase-3 levels remained high 72 hours after ischemia. These results indicate that there are temporal differences in the activation status of the autophagic and apoptotic pathways. This suggests that therapeutic targeting of these pathways should take into consideration their unique temporal dynamics.

Immunogenicity and protective efficacy conferred by a novel recombinant Mycobacterium bovis bacillus Calmette-Guérin strain expressing interleukin-12p70 of human cytokine and Ag85A of Mycobacterium tuberculosis fusion protein

Mycobacterium bovis bacillus Calmette-Guérin (BCG) immunization provides protection against tuberculosis (TB) in infants, but the antituberculosis protective immunity wanes gradually after initial immunization and lasts less than 15 years. Therefore, more efficacious vaccines are urgently needed. In this study, we constructed a new tuberculosis vaccine of recombinant BCG strain (rBCG-IA), which could express IL-12p70 of human cytokine and Ag85A of M. tuberculosis fusion protein, and investigated its immunogenicity in BALB/c mice by measuring antibody titres, proliferation rate of splenocytes, ratios of CD4(+) T and CD8(+) T cells stimulated by specific antigens and levels of IFN-γ production in antigen-stimulated splenocyte cultures. Meanwhile, we evaluated its protective efficacy against M. tuberculosis H37Rv infection through detecting lung histopathology, organ bacterial loads and lung acid-fast stain. Immunogenicity experiments illustrated that from 2nd to 8th week after immunization, the rBCG-IA vaccine was able to induce the highest level of antibody titres, proliferation rate of splenocytes and IFN-γ production among groups and gained improved ratio of CD4(+) T and CD8(+) T cells from 6th to 8th week after vaccination. And from 2nd to 8th week after M. tuberculosis H37Rv infection, the score of pathology and bacterial loads in the rBCG-IA group were obviously lower than that in rBCG-I group, rBCG-A group or control group (PBST group), but similar to that in BCG group. This study suggested that rBCG-IA was able to elicit stronger humoral and cellular immune responses, but could only confer similar protective efficacy compared with its parental BCG vaccine.

Evaluation of protective efficacy conferred by a recombinant Mycobacterium bovis BCG expressing a fusion protein of Ag85A-ESAT-6

BACKGROUND

We previously constructed a recombinant bacille Calmette-Guérin (rBCG-AE) strain that could express a fused Ag85A-ESAT-6 protein. That study suggested that the rBCG-AE strain was able to induce a higher titer of antibody and elicit a more long-lived and stronger Th1-type cellular immune responses than the parental BCG strain, the rBCG-A strain (i.e., expressing Ag85A), or the rBCG-E strain (i.e., expressing ESAT-6).

METHODS

In the current study, we further investigated the strain's protective efficacy against Mycobacterium tuberculosis H37Rv infection in BALB/c mice through evaluating organ bacterial loads, lung histopathology, lung immunohistochemistry, and net weight gain or loss by using conventional BCG, rBCG-A, and rBCG-E as the controls.

RESULTS

From the 3rd to 9th weeks after the challenge infection, the bacterial counts were significantly lower in tissues (e.g., spleen and lung tissues) in the mice immunized with rBCG-AE than in the control group, but were higher than the counts in the BCG group. The pathological damage in the lung tissues of the rBCG-AE group gradually improved from the 6th to 9th weeks after being infected with M. tuberculosis H37Rv, but the score of pathological changes in the rBCG-AE group was obviously higher than the score in the BCG group. There was no difference in the percentage of IFN-γ and iNOS positive cells in the lung tissues of the rBCG-AE and BCG groups.

CONCLUSION

The results suggest that rBCG-AE can not promote protective efficacy against M. tuberculosis H37Rv infection, compared to the BCG vaccine.

Improved immunogenicity of recombinant Mycobacterium bovis bacillus Calmette-Guérin strains expressing fusion protein Ag85A-ESAT-6 of Mycobacterium tuberculosis

Early secretory antigen target 6 (ESAT-6) is a dominant target for cell-mediated immunity in the early phase of tuberculosis (TB) in patients with TB, causing T-cell proliferation and gamma interferon (IFN-γ) production, which has been considered to be a protective antigen that can be used for future vaccine development. Ag85A is the most essential component for bacterial survival within macrophages and has been used in numerous vaccine preparations, which can induce strong cellular immune responses. In this study, we constructed a new recombinant bacilli Calmette-Guérin (BCG) strain (rBCG-AE) that could express fusion protein Ag85A-ESAT-6 of Mycobacterium tuberculosis and evaluated its immunogenicity in BALB/c mice. There was no evidence for increased virulence of this rBCG. Our experiments illustrated that the rBCG-AE was able to induce higher titer of antibody and elicit more long-lasting and stronger Th1 type cellular immune responses than the parental BCG strain, or rBCG-A (expressing Ag85A) strain, or rBCG-E (expressing ESAT-6) strain, which are characterized by the strong antibody response, the proliferation rate of splenocytes, the ratio of CD4(+) T and CD8(+) T cells stimulated by tuberculin-purified protein derivative and elevated levels of IFN-γ in antigen-stimulated splenocyte cultures. The results show that rBCG-AE is an improved TB vaccine for further study.

Pharmacokinetics and tissue distribution of zidovudine in rats following intravenous administration of zidovudine myristate loaded liposomes

Liposomes accumulating in the reticuloendothelial system (RES) appear to be a promising vehicle to improve the therapeutic index of anti-HIV drugs such as zidovudine (AZT). Since the entrapment efficiency of AZT in liposomes was found to be low and AZT leakage from liposomes is fast, zidovudine myristate (AZT-M) was synthesized as a prodrug, and AZT-M incorporated liposomes in a lyophilized form were prepared with an average diameter of 90 nm and an encapsulation efficiency of 98% after reconstitution. The pharmacokinetic profiles and tissue distribution of AZT after i.v. administration of AZT-M liposomes in rats were investigated, and the results were compared with those after i.v. administration of AZT solution. AZT levels in plasma were significantly higher following application of AZT-M liposomes compared with AZT solution, and AUC0_infinity increased from 5.0 +/- 0.7 micromol x min x ml(-1) to 8.2 +/- 1.7 micromol x min x ml(-1) accordingly. Tissue distribution studies also confirmed higher concentrations of AZT in organs of RES and brain, suggesting that AZT-M liposomes might be promising candidates for therapy of HIV infections.

[Synthesis, characterization and fluorescence property of europium ternary complex p-nitrophenylacetic acid and 1, 10-phenanthroline]

The europium ternary solid complex containing p-nitrophenylacetic acid and 1, 10-phenanthroline was synthesized in this work, and the chemical formula of this compound was determined to be EuL3 phen by elemental analysis. The complex has been characterized by analysis of molar conductivity, TG-DTA, IR and UV. The fluorescence spectra of this Eu3+ complex has been investigated also in this paper.