[Clinical analysis of retropharyngeal lymph node metastasis in patients with hypopharyngeal squamous cell carcinoma]

Objective: To analyze the incidence and the related risk factors of retropharyngeal lymph node metastasis in patients with hypopharyngeal squamous cell carcinoma, evaluate the accuracy of preoperative enhanced CT in judging retropharyngeal lymph node metastasis, and investigate the impact of retropharyngeal lymph node metastasis on the prognosis. Methods: Retrospective analyses were made on 398 patients with hypopharyngeal squamous cell carcinoma who underwent surgery as the primary therapy and accepted retropharyngeal lymph node exploration and clearance during surgery in Shandong Provincial ENT Hospital from January 2014 to December 2019. Multivariate logistic regression analysis was used to clarify the related risk factors of retropharyngeal lymph node metastasis. Multivariate Cox regression analysis was used to investigate the impact of retropharyngeal lymph node metastasis on prognosis. The retropharyngeal lymph nodes of 218 cases with available preoperative enhanced CT images were evaluated by two experienced radiologists and compared with postoperative pathological results. Results: Retropharyngeal lymph node metastasis were confirmed in 54 of 398 (13.6%) cases according to postoperative pathology. The sensitivity and specificity of preoperative enhanced CT in the diagnosis of retropharyngeal lymph node metastasis were 34.6% and 91.1%, respectively, and the overall accuracy was 84.4%. Multivariate logistic regression analysis showed that the site of the primary lesion and pathological N stage were independent risk factors for retropharyngeal lymph node metastasis in hypopharyngeal squamous cell carcinoma. Patients with primary lesion located in the posterior wall of hypopharynx (OR=4.83, 95% CI: 1.27-18.40), N2 stage (OR=6.30, 95% CI: 2.25-17.67), and N3 stage (OR=26.89, 95% CI: 5.76-125.58) were prone to retropharyngeal lymph node metastasis. The 5-year overall survival rate of the 398 patients was 50.4%, and the 5-year disease-free survival rate was 48.3%. Multivariate Cox regression analysis showed that T stage, N stage, retropharyngeal lymph node metastasis, and radiotherapy were independent influencing factors for overall survival (T stage: HR=1.28, 95% CI: 1.06-1.54; N stage: HR=1.26, 95% CI: 1.14-1.40; retropharyngeal lymph node metastasis: HR=2.13, 95% CI: 1.47-3.08; radiotherapy: HR=0.54, 95% CI: 0.38-0.76) and disease-free survival of patients with hypopharyngeal squamous cell carcinoma (T stage: HR=1.26, 95% CI: 1.06-1.51; N stage: HR=1.25, 95% CI: 1.13-1.37; retropharyngeal lymph node metastasis: HR=2.24, 95% CI: 1.56-3.21; radiotherapy: HR=0.55, 95% CI: 0.40-0.77). Conclusions: Metastasis of retropharyngeal lymph nodes in hypopharyngeal squamous cell carcinoma is not rare. Enhanced CT is of low accuracy and limited value in diagnosing retropharyngeal lymph node metastasis. Primary lesions located in the posterior wall of the hypopharyngx, N2 stage, and N3 stage are independent high-risk factors for retropharyngeal lymph node metastasis. The prognosis of hypopharyngeal cancer patients with retropharyngeal lymph node metastasis is worse, and active surgical exploration and clearance can effectively reduce the mortality caused by retropharyngeal lymph node metastasis.

Long noncoding RNA BBOX1-AS1 increased radiotherapy sensitivity in colorectal cancer by stabilizing and activating PFK1

PURPOSE

Our study explored the effect of long noncoding RNA BBOX1-AS1 on colorectal cancer (CRC) radiosensitivity in vivo and in vitro.

METHODS

Differentially expressed lncRNAs in CRC were screened using a bioinformatics database and an online prediction website. The expression of BBOX1-AS1 in tissue samples was analyzed via real-time quantitative PCR (RT-qPCR). Subcellular localization of BBOX1-AS1 in CRC cells was analyzed using fluorescence in situ hybridization (FISH). The correlation between BBOX1-AS1 and PFK1 expression levels in CRC tissues was analyzed via Pearson's correlation coefficient. The effect of BBOX1-AS1 on PFK1 stability was investigated using RNA and protein stability testing. RNA Binding Protein Immunoprecipitation (RIP) and RNA pull-down assays were used to confirm the binding of BBOX1-AS1 to PFK1.

RESULTS

BBOX1-AS1 was highly expressed in CRC and associated with poor prognosis. Similarly, it was highly expressed in CRC tissues and CRC cell lines. In addition, BBOX1-AS1 promoted the proliferation, invasion, migration, and glycolysis of CRC cells and inhibited apoptosis. RIP and RNA pull-down experiments confirmed that BBOX1-AS1 bound to PFK1. RNA stability and protein stability experiments showed that BBOX1-AS1 affected the stability of PFK1 mRNA and protein. Furthermore, we confirmed that BBOX1-AS1 increased radiation resistance through the regulation of PFK1 expression.

CONCLUSIONS

BBOX1-AS1 promoted the proliferation, invasion, migration, and glycolysis of CRC cells through stabilization of the expression of PFK1. BBOX1-AS1 also inhibited CRC cell apoptosis and increased radiotherapy resistance in CRC cells.

[Efficacy of surgical comprehensive therapy for 456 cases of hypopharyngeal carcinoma]

Objective: To retrospectively analyse the efficacy of surgerical comprehensive treatment for hypopharyngeal cancer. Methods: Four hundred and fifty-six cases of hypopharyngeal squamous cell carcinoma treated from Jan 2014 to Dec 2019 were analyzed retrospectively, including 432 males and 24 females, aged 37-82 years old. There were 328 cases of pyriform sinus carcinoma, 88 cases of posterior pharyngeal wall carcinoma, and 40 cases of postcricoid carcinoma. According to American Joint Committe on Cancer(AJCC) 2018 criteria, 420 cases were of stage Ⅲ or Ⅳ; 325 cases were of T3 or T4 stage. Treatment methods included surgery alone in 84 cases, preoperative planned radiotherapy plus surgery in 49 cases, surgery plus adjuvant radiotherapy or concurrent chemoradiotherapy in 314 cases, and inductive chemotherapy plus surgery and adjuvant radiotherapy in 9 cases. The primary tumor resection methods included transoral laser surgery in 5 cases, partial laryngopharyngectomy in 74 cases, of them 48 cases (64.9%) presented with supracricoid hemilaryngopharyngectomy, total laryngectomy with patial pharyngectomy in 90 cases, total laryngopharyngectomy or with cervical esophagectomy in 226 cases, and total laryngopharyngectomy with total esophagectomy in 61 cases. Among 456 cases, 226 cases received reconstruction surgery with free jejunum transplantation, 61 cases with gastric pull-up, and 32 cases with pectoralis myocutaneous flaps. All patients underwent retropharyngeal lymph node dissection, and high-definition gastroscopy was performed during admission and follow-up. SPSS 24.0 software was used to analyze the data. Results: The 3-year and 5-year overall survival rates were respectively 59.8%, and 49.5%. The 3-year and 5-year disease specific survival rates were respectively 69.0% and 58.8%. Total metastasis rate of retropharyngeal lymph nodes was 12.7%. A total of 132 patients (28.9%) suffered from simultaneous and metachronous multiple primary carcinoma of the hypopharynx. Multivariate Logistic regression analysis showed that T3-4 disease, cervical lymph node metastasis, retropharyngeal lymph node metastasis and postoperative adjuvant radiotherapy were independent factors affecting the prognosis of patients (all P<0.05). As of April 30, 2022, a total of 221 patients died during follow-up, of 109 (49.3%) with distant metastases, which were the main cause of death. Conclusions: The efficacy of comprehensive treatment for hypopharyngeal cancer can be improved by accurate preoperative evaluation, improved surgical resection, active retropharyngeal lymph node dissection and full process intervention of the second primary cancer.

[The effect of cervical lymph node metastasis density on prognosis of hypopharyngeal carcinoma]

Objective: To investigate the relationship between the cervical lymph node density (LND) and the prognosis of hypopharyngeal carcinoma. Methods: The clinical and pathological data of 241 patients with hypopharyngeal carcinoma who underwent surgery in Shandong Provincial ENT Hospital from January 2014 to December 2017 were retrospectively analyzed, including 229 males and 12 females, aged 37-81 years. The LND was calculated, i.e. the ratio of the number of lymph nodes with metastasis to the total number of lymph nodes removed. The patients were divided into low LND group and high LND group based on the cutoff value of LND determined by receiver operating characteristic curve (ROC curve). The univariate and multivariate analyses of the disease-free survival (DFS) and the overall survival (OS) were performed in two groups. Results: With the cutoff value of 0.068, 165 patients were in the low LND group (<0.068) and 76 patients in the high LND group (≥0.068). T stage, N stage, maximum lymph node diameter, extracellular invasion of lymph node, and postpharyngeal lymph node metastasis were associated with LND (statistical values were -3.15, -6.82, 23.37, 20.44, and 30.18, respectively, all P values were<0.05). The univariate analysis showed that age, T stage, N stage, maximum diameter of cervical lymph nodes, extracapsular invasion, retropharyngeal lymph node metastasis and LND were the main factors affecting the patients' DFS (χ²=9.31, 7.30, 20.09, 15.30, 9.04, 19.44, 50.27, all P values<0.05) and OS (χ² were 5.02, 12.94, 18.28, 15.91, 7.95, 16.88, 49.45, all P values<0.05). Multivariate analysis showed that patients with age≤60 years old and LND≥0.068 had reduced DFS [HR values were 0.61 (95%CI 0.43-0.88) and 2.23 (95%CI 1.44-3.45), both P values<0.05]; patients with advanced T stage and LND≥0.068 had reduced OS [HR values were 1.73 (95%CI 1.02-2.93) and 2.39 (95%CI 1.51-3.80), both P values<0.05]. Conclusion: LND is a prognostic factor for patients with hypopharyngeal carcinoma after surgery, with worse prognosis in patients with LND≥0.068.

Andrographolide enhanced radiosensitivity by downregulating glycolysis via the inhibition of the PI3K-Akt-mTOR signaling pathway in HCT116 colorectal cancer cells

Objective

Radiotherapy plays an important role in the treatment of colorectal cancer (CRC). However, some patients benefit minimally from radiotherapy because of radioresistance. This study investigated the effects of andrographolide on radiosensitivity in HCT116 CRC cells and examined its mechanism of action.

Methods

Cell survival, proliferation, apoptosis, and migration were evaluated using MTT, colony formation, flow cytometry, and Transwell cell invasion assays, respectively. Glycolysis-related indicators were measured to examine cell glycolytic activity. The expression of related proteins was detected by western blotting.

Results

After andrographolide treatment, the expression of phosphoinositide 3-kinase (PI3K)-Akt-mammalian target of rapamycin (mTOR) signaling pathway-related proteins, glycolytic activity, and cell survival and invasion rates were decreased in HCT116 cells. Andrographolide plus irradiation increased apoptosis and decreased survival, invasion, and colony formation compared with the effects of irradiation alone.

Conclusion

Andrographolide enhanced radiosensitivity by downregulating glycolysis via inhibition of the PI3K-Akt-mTOR signaling pathway in HCT116 cells.

SiRNA targeting PFK1 inhibits proliferation and migration and enhances radiosensitivity by suppressing glycolysis in colorectal cancer

PURPOSE

This study explored the effects of phosphofructokinase-1 (PFK1) on the radiosensitivity of colorectal cancer (CRC) in vivo and in vitro and the underlying mechanisms.

METHODS

Tissue samples from 48 patients with rectal cancer who had received neoadjuvant radiotherapy followed by surgery were analyzed. The expression of PFK1 in tissue samples was semi-quantitated by immunohistochemistry, and its relationship with clinicopathological features was analyzed. The effects of PFK1 knockdown on the survival, apoptosis, migration, and radiosensitivity of CRC cells were evaluated. Glycolysis-related indicators were used to examine glycolytic activity. The effects of PFK1 on the radiosensitivity of CRC in vivo were assessed by measuring tumor formation in nude mice.

RESULTS

PFK1 was overexpressed in rectal cancer and was higher in radiation-resistant tumors than in radiation-sensitive tumors. SiRNA-induced PFK1 silencing increased apoptosis and inhibited migration and proliferation of CRC cells. Knockdown of PFK1 made the CRC cells sensitive to ionizing radiation in vivo. Oligomycin partially restored the expression of PFK1, enhanced glycolysis, and reversed the enhanced radiosensitivity of CRC cells induced by siRNA-PFK1. Downregulation of PFK1 combined with irradiation inhibited growth of nude mice xenografts, which was related to an increase in apoptosis.

CONCLUSIONS

Our study indicates that high expression of PFK1 is negatively correlated with radiosensitivity in CRC and likely accelerates the proliferation and migration of CRC cells. Downregulation of PFK1 may enhance the radiosensitivity of CRC cells in vivo and in vitro by inhibiting glycolysis.

[The oncologic and functional outcomes of supracricoid partial laryngectomy for the treatment of laryngeal cancer]

Objective: To evaluate the oncologic and functional outcomes of laryngeal squamous cell carcinomas treated by supracricoid laryngectomy. Methods: The clinical data of 134 patients with laryngeal cancer who underwent supracricoid laryngectomy with cricohyoidoepiglottopexy (CHEP) or cricohyoidopexy (CHP) between July 2005 and April 2014 at Shandong Provincial ENT Hospital were retrospectively reviewed. Ninety-one patients including 31 cases of stage Ⅰ, 36 of stage Ⅱ, 18 of stage Ⅲ and 6 of stage Ⅳ underwent CHEP and 43 patients underwent CHP. Two patients received CHEP due to recurrence after open surgery and laser surgery. Three patients received CHP due to the recurrence of disease after open surgery and postradiotherapy persistence of disease. The Kaplan-Meier method was used to calculate the 3-year and 5-year survival rates. The Chi-square test was used to compare the survival rates between different surgical procedures. Results: All 91 patients who underwent CHEP had successful removals of PEG tubes, and 88 (96.7%) of them had tracheostomy tube decannulation. Among 43 patients with CHP, 42(97.6%) cases removal of PEG tubes(97.6%), including and 40(93.0%) cases with tracheostomy tube decannulation. There was one patient with local recurrence in all cases. In CHEP group, 3-year local control rate was 98.2%; 3-year and 5-year overall survival rate were 94.5% and 93.9%, respectively. In CHP group, 3-year local control rate was 97.6%; 3-year and 5-year overall survival rates were 86.0% and 83.3%, respectively. Pharyngeal fistula appeared in 2 cases of CHEP group and 4 cases of CHP group, and all of them were cured by conservative treatment. Conclusion: Supracricoid laryngectomy shows excellent oncologic and functional results for treatment of laryngeal cancer while maintaining laryngeal functions, especially in terms of local control rate and tracheostomy tube decannulation.

[Treatment and prognosis of 264 patients with hypopharyngeal carcinoma]

Objective: To investigate the key factors influencing the prognosis of hypopharyngeal carcinoma and the therapeutic methods improving the efficacy of treatments for hypopharyngeal carcinoma. Methods: Two hundred and sixty-four cases of hypopharyngeal squamous cell carcinoma treated from May 2010 to May 2015 were analyzed retrospectively. There were 211 cases of pyriform sinus carcinoma, 37 cases of posterior pharyngeal wall carcinoma, and 16 cases of postcricoid carcinoma. According to UICC 2002 criteria, 2 cases were for stage Ⅰ, 14 for stage Ⅱ, 32 for stage Ⅲ and 216 for stage Ⅳ. Postoperative circumferential defects existed in 112 (42.4%) cases, and 86 of them were reconstructed with free jejunum transplantation. Among all cases, 54 patients (20.5%) had the preservation of laryngeal functions after surgery and 210 patients (79.5%) with total laryngectomy; 238 cases (90.2%) underwent bilateral cervical lymph node dissection and 203 patients received posterior pharyngeal lymph node exploration and dissection, with positive metastases for posterior pharyngeal lymph nodes in 36 cases (17.7%). Eight cases with cervical lymph node metastasis extensively involving the soft tissue, prevertebral fascia or encases carotid artery received preoperative radiotherapy of 50 Gy. After surgery 13 patients received concurrent radiotherapy and chemotherapy, 337 underwent adjuvant radiotherapy with a dose of 50-60 Gy each, and 14 patients did not receive radiotherapy or did not completed their radiotherapy programs. SPSS 13.0 saftware was used to analyze the data. Results: All patients were followed up for more than 2 years. With Kaplan-Meier method, the 2-, 3- and 5-years survival rates were 69.6%, 62.8% and 51.3%, respectively. There were significant differences in 3-year survival rates between T1-2 group (75.5%) and T3-4 group (59.2%) (χ(2)=4.282 P=0.039), N0 group (81.6%) and N+ group (58.2%) (χ(2)=6.802 P=0.009), laryngeal functions preserved (81.8%) and unpreserved group (58.9%) (χ(2)=5.314 P=0.021). Multivariate Logistic regression analysis showed that cervical lymph node metastasis was an independent prognostic factor (P=0.027). The success rate of free jejunum transplantation was 98.8%. Local recurrence, cervical lymph node recurrence, second primary cancer, and distant metastasis accounted respectively for 11.2%, 18.8%, 12.5% and 45.0% of death cases. Conclusions: The prognosis-associated factors for hypopharyngeal carcinoma should be taken into account, including the evaluation of the carcinogenesis of the mucosal area, early screening of premalignant lesion or second primary cancer in the esophagus and dissection of the posterior pharyngeal lymph nodes, which will help to improve the local control rate and recent survival rate in patients with hypopharyngeal cancer.

[Significance of retropharyngeal node dissection in treatment of hypopharyngeal carcinoma]

Objective: investigate the incidence of retropharyngeal lymph node (RPLN) metastasis and the risk factors for RPLN metastasis in hypopharyngeal cancer, and the relationship of planned dissection of the RPLN with the survival and tumor control rates in patients with hypopharyngeal cancer. Methods: A total of 203 patients with hypopharyngeal squamous cell carcinoma who underwent radical surgery as initial treatment from February 2011 to July 2015 were analyzed retrospectively. There were 167 cases of pyriform sinus carcinoma, 23 cases of posterior pharyngeal wall carcinoma, and 13 cases of postcricoid carcinoma. Results: The incidence of RPLN metastasis in HPC was 17.7%, with a highest rate of 43.5% in pharyngeal wall carcinoma. The incidence of RPLN metastasis in T3-4 pyriform sinus carcinoma was 18.3%, which significantly higher than 2.8% in T1-2 cases(χ(2)=5.360, P=0.020). The rate of RPLN metastasis was 23.8% in N2b-3 and 8.6% in N0-2a, with a statistically significant difference(χ(2)=7.637, P=0.006). There was no statistically significant difference in overall survival rates between patients with and without RPLN metastasis(P>0.05). Data were analyzed by SPSS 13.0 software. Conclusions: RPLN metastasis is not rare in hypopharyngeal carcinoma. Planned dissection of the RPLN should be performed with the initial surgery in patients with advanced hypopharyngeal cancer, especially posterior pharyngeal wall carcinoma, T3-4 pyriform sinus carcinoma and staged N2b-3 disease, which can reduce the regional recurrence rate and provided with a better prognosis.

Reliable Radiation Technique to Minimize Ovarian Dose During Radiation Prophylaxis of Heterotopic Ossification

BACKGROUND/AIM

Scattered radiation during radiotherapy (RT) directed at the hip joint poses concerns about ovarian function in patients of reproductive age. Here, we report the impact of using a split-beam technique (SBT) and different photon energies on the total ovary dose during radiation prophylaxis of heterotopic ossification (HO).

PATIENTS AND METHODS

This was a single-institution, retrospective study of 32-patients with traumatic acetabular fractures (TAF). All underwent surgery followed by CT-based-RT within 72 h in a single fraction of 700 cGy. Ipsilateral (IL) and contralateral (CL) ovaries (OV) were contoured separately and dose volume histograms (DVH) generated. Additional planning trials were created for each patient by utilizing a SBT medially and by using different photon energies (6-18 MV) to investigate the difference in ovary dose among these maneuvers.

RESULTS

The median Mean-dose delivered to ILOV was 59 cGy and the median Max-dose was 177 cGy. CLOV median Mean-dose was 6 cGy and median Max-dose was 10 cGy. SBT at the medial edge of the field led to a 27% and 22% dose reduction in the median Mean and Max. doses, respectively, to ILOV; 9% and 5% reduction was seen in the median Mean and Max. doses, respectively, to CLOV. Higher photon energies (10-18 MV) led to an additional 28% and 16 % reduction in median Mean and Max. doses, respectively, to ILOV when compared to those from 6 MV. The CLOV median Mean dose was reduced by 18% and the Max. dose was reduced by 12%.

CONCLUSION

A biologically significant radiation dose is delivered to the ovaries during HO radiation prophylaxis at the hip joints. Ipsilateral ovarian dose could be reduced by half and contralateral by one-quarter by using CT-based treatment planning with a medial SBT and photon energies above 6 MV. We suggest using no more than 10 MV to minimize neutron contamination. Those techniques should be the standard of care as it provides a reliable method for minimizing the radiation dose to the ovaries, consequently, maximizing female fertility preservation during HO radiation prophylaxis. All female patients in childbearing age should be fully informed about ovarian radiation exposure and possible temporary alteration in ova production and morphology.

[Reconstruction with free jejuna flap for the defect after removal of hypopharyngeal and cervical esophageal caneer: clinical analyses of 103 cases]

Objective: To report our experience in reconstruction with free jejunal flap for circumferential defect following resection of hypopharygeal and cervical esophageal carcinoma. Methods: A retrospective analysis was conducted to evaluate the outcomes of reconstruction with free jejunal flaps for circumferential defects in 103 patients treated from Aug 2008 to Mar 2015. Among them, 84 were hypopharyngeal carcinoma and 19 were cervical esophageal carcinoma; 31 patients had total pharyngolaryngectomy, 70 had total pharyngolaryngectomy and cervical esophagectomy and 2 had laryngeal preservation. All patients underwent bilateral neck dissection and 84 underwent retropharyngeal lymph node dissection. Results: The 3 year overall survival rate was 51.6% and disease-specific survival rate was 50%. The 5 year overall survival rate was 39.1%. No in-hospital death, one patient had unsalvageable flap failure and underwent second reconstruction with free jejunal flap. The success rate for the free jejunal flaps was 99% (102/103). Pharyngocutanous fistula occurred in 3 patients and all healed with conservative treatment. Satisfactory oral intake was achieved in all patients. Conclusions: Oncological and functional outcomes of reconstruction with free jejunal flap for circumferential defects of hypopharynx and cervical esophagus were satisfying. Multidisciplinary cooperation is helpful to improve surgical success rate. Free jejunal flap is an ideal method for reconstruction of circumferential hypopharyngeal and cervical esophageal defects after removal of tumor.

Testicular Dose During Prophylaxis of Heterotopic Ossification with Radiation Therapy

AIM

A single-institution, retrospective study was performed to investigate potential techniques to minimize radiation exposure to the testicles during heterotopic ossification (HO) prophylaxis. We report the impact of split-beam technique (SBT) and different photon energies on the total dose of radiation received by the testicles during prophylaxis of HO.

MATERIALS AND METHODS

Between 2008 and 2010, we identified 64 patients with traumatic acetabular fractures who underwent surgery followed by radiation therapy (RT) without testicular shielding. Postoperative RT was delivered within 72 h in a single fraction of 700 cGy using 6-18 MV photons, without testicular shielding due to patient refusal. All patients underwent 3-D RT planning in which the testicles were contoured as a region of interest and dose-volume histograms (DVH) were generated. Additional treatment planning trials were created for each patient by utilizing a SBT medially and by using different photon energies (6, 10 and 18 MV) to study the effects of these maneuvers on the delivered dose to the testicles.

RESULTS

In reviewing the DVH, it was noted that the mean dose delivered to the testicles was 10 cGy (range=3-40). The maximum dose was 31 cGy (range=7-430). When SBT was utilized, a significant reduction in the mean (44%) and maximum (47%) doses delivered to the testicles was noted. Further reductions in the mean (26%) and maximum (14%) doses were achieved by using higher-energy (10-18 MV) beams. The radiation doses to the testicles from the CT simulation and the two portal images were estimated to be 4 and 1.5 cGy, respectively.

CONCLUSION

Low-dose prophylactic RT to prevent HO around the hip causes a low, but likely biologically meaningful, radiation dose to be delivered to the testicles. This dose could be further reduced by using a medial SBT and photon energies above 6 MV. Testicular shielding should be offered to all male patients receiving such RT. In addition, all patients should be informed about the consequences of testicular radiation as part of their informed consent.

Computerized tomography-based radiotherapy improves heterotopic ossification outcomes

PURPOSE

To report the impact of computerized tomography (CT) based radiotherapy (RT) on heterotopic ossification (HO) outcomes.

METHODS

This is a single institution, retrospective study of 532 patients who were treated for traumatic acetabular fractures (TAF). All patients underwent open-reduction internal-fixation (ORIF) of the TAF followed by RT for HO prophylaxis. Postoperative RT was delivered within 72h, in a single fraction of 7Gy. The patients were divided into 2 groups based on RT planning: CT (A) vs. clinical setup (B).

RESULTS

At a median follow up of 8years the incidence of HO was 21.6%. Multivariate regression analysis revealed that group (A) vs. (B) had HO incidence of 6.6% vs. 24.6% (p<0.001), respectively. Furthermore, HO Brooker grade ≥3 was observed in 2.2% vs. 10.8% (p=0.007) in group (A) vs. (B), respectively. Thus, the odds of developing HO and Brooker grades ≥3 were 4.7 and 4.5 times higher, respectively, in patients who underwent clinical setup.

CONCLUSION

Our data suggest that using CT based RT allowed more accurate delineation of the tissues and better clinical outcomes. Although CT-based RT is associated with additional cost the efficacy of CT-based RT reduces the risk of HO, thereby decreasing the need for additional surgical interventions.

Functional characterization of the recombinant HIV-neutralizing monoclonal antibody 2F5 produced in maize seeds

Monoclonal antibodies (mAbs) that neutralize human immunodeficiency virus (HIV) can be used as microbicides to help prevent the spread of HIV in human populations. As an industry standard, HIV-neutralizing mAbs are produced as recombinant proteins in mammalian cells, but the high manufacturing costs and limited capacity reduce the ability of target populations in developing countries to gain access to these potentially life-saving medicines. Plants offer a more cost-effective and deployable production platform because they can be grown inexpensively and on a large scale in the region where the products are required. Here we show that the maize-derived HIV-neutralizing mAb 2F5 is assembled correctly in planta and binds to its antigen with the same affinity as 2F5 produced in mammalian cells. Although 2F5 has been produced at high levels in non-plant platforms, the yield in maize seeds is lower than previously achieved with another HIV-neutralizing mAb, 2G12. This suggests that the intrinsic properties of the antibody (e.g. sensitivity to specific proteases) and the environment provided by the production host (e.g. the relative abundance of different proteases, potential transgene silencing) may combine to limit the accumulation of some antibodies on a case-by-case basis.

Inhibition of Respiratory Burst Activity in Alveolar Macrophages by Bisbenzylisoquinoline Alkaloids: Characterization of Drug-Cell Interaction

The objective of this study was to investigate the effects of various bisbenzylisoquinoline (BBIQ) alkaloids on respiratory burst activity of alveolar macrophages and to characterize the interaction of these drugs with alveolar phagocytes. BBIQ alkaloids were chosen for study because they exhibit a wide range of antifibrotic potencies in a rat model, with tetrandrine being very effective and tubocurarine being ineffective. These drugs inhibited zymosan-stimulated oxygen consumption with a potency sequence of tetrandrine (TT) approximately fangchinoline (FA) > berbamine (BE) approximately cepharanthine (CE) approximately cycleanine (CY) >> tubocurarine (TU). This inhibition of respiratory burst activity could not be attributed to a drug-induced decline in the ATP content of these pneumocytes. Drug binding to alveolar macrophages was directly dependent on temperature and drug concentration. The sequence for binding capacity was FA > TT approximately BE approximately CY > CE >> TU. Therefore, there was no simple relationship between binding capacity and inhibitory potency. Binding capacity was not related to lipophilicity of these alkaloids. In addition, tetrandrine failed to bind to metabolically dead cells or sonicated macrophage preparations. These data suggest that the interaction of BBIQ alkaloids with phagocytes is not simply nonspecific binding to membrane lipids. Alteration of the cytoskeletal system with vinblastine, taxol, or cytochalasin B decreased tetrandrine binding by approximately 33% when added separately and by 93% when added jointly. Pre-exposure of alveolar macrophages to stimulants increased the ability of BBIQ alkaloids to inhibit both oxygen consumption and superoxide release. These data suggest that the mechanism by which BBIQ alkaloids inhibit activation of phagocytes involves microtubules and bules and microfilaments. Pre-exposure of macrophages to stimulants would change the conformation of cytoskeletal components and may make these structures more susceptible to drug interaction.

A single methionine residue dictates the kinetic mechanism of interprotein electron transfer from methylamine dehydrogenase to amicyanin

Amicyanin is a type 1 copper protein that is the natural electron acceptor for the quinoprotein methylamine dehydrogenase (MADH). A P52G amicyanin mutation increased the Kd for complex formation and caused the normally true electron transfer (ET) reaction from O-quinol MADH to amicyanin to become a gated ET reaction (Ma, J. K., Carrell, C. J., Mathews, F. S., and Davidson, V. L. (2006) Biochemistry 45, 8284-8293). One consequence of the P52G mutation was to reposition the side chain of Met51, which is present at the MADH-amicyanin interface. To examine the precise role of Met51 in this interprotein ET reaction, Met51 was converted to Ala, Lys, and Leu. The Kd for complex formation of M51A amicyanin was unchanged but the experimentally determined electronic coupling increased from 12 cm-1 to 142 cm-1, and the reorganization energy increased from 2.3 to 3.1 eV. The rate and salt dependence of the proton transfer-gated ET reaction from N-quinol MADH to amicyanin is also changed by the M51A mutation. These changes in ET parameters and rates for the reactions with M51A amicyanin were similar to those caused by the P52G mutation and indicated that the ET reaction had become gated by a similar process, most likely a conformational rearrangement of the protein ET complex. The results of the M51K and M51L mutations also have consequences on the kinetic mechanism of regulation of the interprotein ET with effects that are intermediate between what is observed for the reaction of the native amicyanin and M51A amicyanin. These data indicate that the loss of the interactions involving Pro52 were primarily responsible for the change in Kd for P52G amicyanin, while the interactions involving the Met51 side chain are entirely responsible for the change in ET parameters and conversion of the true ET reaction of native amicyanin into a conformationally gated ET reaction.

Correlation of rhombic distortion of the type 1 copper site of M98Q amicyanin with increased electron transfer reorganization energy

Mutation of the axial Met ligand of the type 1 copper site of amicyanin to Ala or Gln yielded M98A amicyanin, which exhibits typical axial type 1 ligation geometry but with a water molecule providing the axial ligand, and M98Q amicyanin, which exhibits significant rhombic distortion of the type 1 site (Carrell, C. J., Ma, J. K., Antholine, W. E., Hosler, J. P., Mathews, F. S., and Davidson, V. L. (2007) Biochemistry 46, 1900-1912). Despite the change of the axial ligand, the M98Q and M98A mutations had little effect on the redox potential of copper. The true electron transfer (ET) reactions from O-quinol methylamine dehydrogenase to oxidized native and mutant amicyanins revealed that the M98A mutation had little effect on kET, but the M98Q mutation reduced kET 45-fold. Thermodynamic analysis of the latter showed that the decrease in kET was due to an increase of 0.4 eV in the reorganization energy (lambda) associated with the ET reaction to M98Q amicyanin. No change in the experimentally determined electronic coupling or ET distance was observed, confirming that the mutation had not altered the rate-determining step for ET and that this was still a true ET reaction. The basis for the increased lambda is not the nature of the atom that provides the axial ligand because each uses an oxygen from Gln in M98Q amicyanin and from water in M98A amicyanin. Comparisons of the distance of the axial copper ligand from the equatorial plane that is formed by the other three copper ligands in isomorphous crystals of native and mutant amicyanins at atomic resolution indicate an increase in distance from 0.20 A in the native to 0.42 A in M98Q amicyanin and a slight decrease in distance for M98A amicyanin. This correlates with the rhombic distortion caused by the M98Q mutation that is clearly evident in the EPR and visible absorption spectra of the protein and suggests that the extent of rhombicity of the type 1 copper site influences the magnitude of lambda.

Generation of novel copper sites by mutation of the axial ligand of amicyanin. Atomic resolution structures and spectroscopic properties

Amicyanin from Paracoccus denitrificans is a type 1 copper protein with three strong equatorial copper ligands provided by nitrogens of His53 and His95 and the sulfur of Cys92, with an additional weak axial ligand provided by the sulfur of Met98. Met98 was replaced with either Gln or Ala. As isolated, the M98A and M98Q mutant proteins contain zinc in the active site. The zinc is then removed and replaced with copper so that the copper-containing proteins may be studied. Each of the mutant amicyanins exhibits a marked decrease in thermal stability relative to that of native amicyanin, consistent with the weaker affinity for copper. Crystal structures were obtained for the oxidized and reduced forms of M98A and M98Q amicyanins at atomic resolution (<or=1.0 A). The crystal structure of oxidized M98A amicyanin exhibits a type 1 ligation geometry but with the axial ligand provided by a water, which fills the void left by the mutation of Met to Ala. The protein undergoes a reversible switch in ligation geometry when going from the aqueous to the frozen state. The visible absorption spectrum in solution is characteristic of type 1 copper, consistent with the crystal structure. On freezing, the blue color is lost, and EPR spectroscopy reveals that the copper is primarily type 2. The crystal structure of reduced M98A amicyanin exhibits an unprecedented ligation geometry in which the His95-Cu coordination is broken, and copper is left with only two ligands from His53 and Cys92 in an almost linear coordination. The replacement of Met98 with Gln yielded a type 1 copper site with increased rhombicity evident from its EPR and visible absorption spectra, and an increase in distance from Cu to the trigonal equatorial plane seen in the crystal structure. Gln98 coordinates more strongly with copper than Met, and the oxidized and reduced forms each exhibit two alternate conformers. EPR and metal analysis of oxidized M98Q amicyanin indicate that a small population of the protein contains weakly bound type 2 copper, which may be removed by washing with EDTA. These results demonstrate that the identity as well as position and rigidity of the axial ligand of the type 1 copper site has a profound influence in the uptake specificity of metal ions, protein stability, and determination of the active site geometry and its spectroscopic properties.

Site-directed mutagenesis of proline 52 to glycine in amicyanin converts a true electron transfer reaction into one that is conformationally gated

Amicyanin is a type I copper protein that is the natural electron acceptor for the quinoprotein methylamine dehydrogenase (MADH). The conversion of Proline52 of amicyanin to a glycine does not alter the physical and spectroscopic properties of the copper binding site, but it does alter the rate of electron transfer (ET) from MADH. The values of electronic coupling (H(AB)) and reorganization energy (lambda) that are associated with the true ET reaction from the reduced O-quinol tryptophan tryptophylquinone (TTQ) of MADH to oxidized amicyanin are significantly altered as a consequence of the P52G mutation. The experimentally determined H(AB) increases from 12 to 78 cm(-1), and lambda increases from 2.3 to 2.8 eV. The rate and salt-dependence of the proton transfer-gated ET reaction from N-quinol MADH to amicyanin are also changed by the P52G mutation. Kinetic data suggests that a new common reaction step has become rate-limiting for both the true and gated ET reactions that occur from different redox forms of MADH. A comparison of the crystal structures of P52G amicyanin with those of native amicyanin free and in complex with MADH provided clues as to the basis for the change in ET parameters. The mutation results in the loss of three carbons from Pro52 and the movement of the neighboring residue Met51. This reduces the number of hydrophobic interactions with MADH in the complex and perturbs the protein-protein interface. A model is proposed for the ET reaction with P52G amicyanin in which the most stable conformation of the protein-protein complex with MADH is not optimal for ET. A new preceding kinetic step is introduced prior to true ET that requires P52G amicyanin to switch from this redox-inactive stable complex to a redox-active unstable complex. Thus, the ET reaction of P52G amicyanin is no longer a true ET but one that is conformationally gated by the reorientation of the proteins within the ET protein complex. This same reaction step now also gates the ET from N-quinol MADH, which is normally rate-limited by a proton transfer.

The ligand geometry of copper determines the stability of amicyanin

Solution differential scanning calorimetry (DSC) of oxidized amicyanin, a Type I copper protein, at pH 7.5 reveals two thermal transitions. The major transition at 67.7 degrees C corresponds to the disruption of the Cys(92) thiolate to Cu(II) charge transfer as evidenced by a corresponding temperature-dependent loss of amicyanin visible absorbance. A minor transition at 75.5 degrees C describes the further irreversible protein unfolding. Reduced amicyanin exhibits a pH-dependent change of the copper ligand geometry. At pH 8.5 where the Type I tetrahedral geometry is maintained, DSC reveals two thermal transitions with T(m) values similar to that of oxidized amicyanin. At pH 6.2 where the Cu(I) coordination is trigonal planar, reduced amicyanin exhibits a single thermal transition with a lower T(m) of 64.0 degrees C. Apoamicyanin, from which copper has been removed, also exhibits a single thermal transition but with a much lower T(m) of 51.8 degrees C. Thus, the thermal stability of amicyanin is dictated both by the presence or absence of copper and its ligand geometry, but not its redox state. The physiological relevance of these data is discussed.

Effect of postmortem delay on imidazoline receptor-binding proteins in human and mouse brain

Immunoreactive proteins of 45-kD and 29/30-kD doublet bands are candidate imidazoline receptor binding proteins (IRBP) based on associations with I(1) or I(2) binding sites, respectively. It was reported that the density of cortical membrane 29/30-kD I(2) protein is diminished whereas a 45-kD I(1) protein is increased in depressed suicide victims versus controls. IRBP immunoreactive bands of similar size have been suggested to be breakdown products of the 170-kD protein known as IRAS (putative full-length I(1) receptor). This study compares nonpathologic human brains collected and frozen after postmortem delays of 13.4 hours +/- 1.7 (SEM) with brains of longer postmortem delays (26.1 hours +/- 1.2). The fresher human brains possessed more full-length IRAS (P = 0.05). In another study, the postmortem decay of IRBP bands in mouse brain was shown to be linear over time. The results are relevant to previous studies of IRBP bands in postmortem brains of depressed suicide victims.

IgG subclass responses in experimental silicosis

Silicosis is a crippling fibrotic lung disease induced by inhaling crystalline silica. In addition to fibrosis, silica inhalation by humans is associated with a number of immunological effects including increased levels of serum immunoglobulins (in particular IgG), increased prevalence of autoantibodies, and autoimmune disease. Recent studies using rodent models have shown that experimental silicosis is associated with a T-helper (TH)1 pattern of T-cell activation in the lungs and lung-associated lymph nodes after silica inhalation, which are also the sites of increased IgG production. We therefore hypothesized that the subclass distribution of IgG production occurring in experimental silicosis would suggest TH1 activation as the primary stimulus for IgG production. Using an ELISPOT assay, we found increased IgG-secreting spot-forming cells of all IgG subclasses in lung-associated lymph nodes taken from silica-exposed rats 3 to 4 months after aerosol exposure to silica. Neither TH1- nor TH2-dependent IgG subclass-secreting cells were selectively enhanced. Our findings suggest that TH1 activation alone does not account for increased production of IgG in experimental silicosis.

A pilot study on anticancer activities of Chinese leek

OBJECTIVES

To investigate the anticancer activities of Chinese leek (Allium tuberosum Rottler; [CL]).

DESIGN

Fresh CL was extracted and reconstituted in phosphate-buffered saline. The in vitro antiproliferation activities of the extract were tested with two murine cancer cell lines and four human cancer cell lines. The in vivo anticancer effects were tested in C57BL mice with lung metastases of B16-F10 melanoma. The mice were inoculated with B16-F10 melanoma cells by intravenous (IV) injection on day 1. CL extract was given on days 6-8 by either IV injection or oral gavage. The lung metastases were examined on day 16.

RESULTS

The extract inhibited the in vitro growth of all six cancer cell lines studied. The dose-response curves were sigmoidal with IC50 (50% inhibition concentrations) in the range of 2.5-13.0 mg of raw material per milliliter for the six cancer cell lines. At the CL concentration of 8-100 mg of raw material per milliliter, all the cells underwent apoptosis, and no live cells were left after being exposed to CL for 4-6 hours. Typical apoptosis-specific cell morphology changes were observed under a microscope. The induction of cancer cell apoptosis by CL extract was further verified by the DNA ladder assay. Treatment with a daily oral dose of the extract (equivalent to 2.5 or 12.5 mg of raw material per gram of body weight) reduced the B16-F10 melanoma lung metastatic colonies in mice by 40% (p < 0.03). IV injection of the extract (equivalent to 1.25 or 6.25 mg of raw material per gram of body weight) did not show any effect.

CONCLUSIONS

CL extract inhibited cancer cell growth and induced apoptosis in vitro. Oral administration of CL extract significantly reduced lung metastases in the present animal model.

Effect of exposure to diesel exhaust particles on the susceptibility of the lung to infection

There are at least three mechanisms by which alveolar macrophages play a critical role in protecting the lung from bacterial or viral infections: production of inflammatory cytokines that recruit and activate lung phagocytes, production of antimicrobial reactive oxidant species, and production of interferon (an antiviral agent). In this article we summarize data concerning the effect of exposure to diesel exhaust particles on these alveolar macrophage functions and the role of adsorbed organic chemicals compared to the carbonaceous core in the toxicity of diesel particles. In vitro exposure of rat alveolar macrophages to diesel exhaust particles decreased the ability of lipopolysaccharide (LPS), a bacterial product] to stimulate the production of inflammatory cytokines interleukin-1 (IL-1) and tumor necrosis factor-alpha (TNF-alpha). Methanol extract exhibited this potential but methanol-washed diesel particles did not. Exposure of rats to diesel exhaust particles by intratracheal instillation also decreased LPS-induced TNF-alpha and IL-1 production from alveolar macrophages. In contrast, carbon black did not exhibit this inhibitory effect. Exposure of rats to diesel exhaust particles by inhalation decreased the ability of alveolar macrophages to produce antimicrobial reactive oxidant species in response to zymosan (a fungal component). In contrast, exposure to coal dust increased zymosan-stimulated oxidant production. In vivo exposure to diesel exhaust particles but not to carbon black decreased the ability of the lungs to clear bacteria. Inhalation exposure of mice to diesel exhaust particles but not to coal dust depressed the ability of the lung to produce the antiviral agent interferon and increased viral multiplication in the lung. These results support the hypothesis that exposure to diesel exhaust particles increases the susceptibility of the lung to infection by depressing the antimicrobial potential of alveolar macrophages. This inhibitory effect appears to be due to adsorbed organic chemicals rather than the carbonaceous core of the diesel particles.

Diesel exhaust particles suppress macrophage function and slow the pulmonary clearance of Listeria monocytogenes in rats

In this study, we tested the hypothesis that exposure to diesel exhaust particles (DEP) may increase susceptibility of the host to pulmonary infection. Male Sprague-Dawley rats received a single dose of DEP (5 mg/kg), carbon black (CB, 5 mg/kg), or saline intratracheally. Three days later, the rats were inoculated intratracheally with approximately 5,000 Listeria monocytogenes and sacrificed at 3, 5, and 7 days postinfection, and we determined the number of viable Listeria in the left lobe of lungs. The remaining lungs underwent bronchoalveolar lavage (BAL) and the retrieved BAL cells were identified and counted. Luminol-dependent chemiluminescence, a measure of reactive oxygen species (ROS) formation, generated by BAL cells was monitored and the levels of nitric oxide and tumor necrosis factor (TNF)-[alpha] produced by macrophages in culture were determined. At 7 days postinfection, we excised the lung-draining lymph nodes and phenotyped the lymphocyte subpopulations. Exposure of rats to DEP, but not to CB, decreased the clearance of Listeria from the lungs. Listeria-induced generation of luminol-dependent chemiluminescence by pulmonary phagocytes decreased by exposure to DEP but not CB. Similarly, Listeria-induced production of NO by alveolar macrophages was negated at 3, 5, and 7 days after inoculation in DEP-exposed rats. In contrast, CB exposure had no effect on Listeria-induced NO production at 3 days after infection and had a substantially smaller effect than DEP at later days. Exposure to DEP or CB resulted in enlarged lung-draining lymph nodes and increased the number and percentage of CD4(+) and CD8(+) T cells. These results showed that exposure to DEP decreased the ability of macrophages to produce antimicrobial oxidants in response to Listeria, which may play a role in the increased susceptibility of rats to pulmonary infection. This DEP-induced suppression is caused partially by chemicals adsorbed onto the carbon core of DEP, because impaired macrophage function and decreased Listeria clearance were not observed following exposure to CB.

Diesel exhaust particles suppress macrophage function and slow the pulmonary clearance of Listeria monocytogenes in rats

In this study, we tested the hypothesis that exposure to diesel exhaust particles (DEP) may increase susceptibility of the host to pulmonary infection. Male Sprague-Dawley rats received a single dose of DEP (5 mg/kg), carbon black (CB, 5 mg/kg), or saline intratracheally. Three days later, the rats were inoculated intratracheally with approximately 5,000 Listeria monocytogenes and sacrificed at 3, 5, and 7 days postinfection, and we determined the number of viable Listeria in the left lobe of lungs. The remaining lungs underwent bronchoalveolar lavage (BAL) and the retrieved BAL cells were identified and counted. Luminol-dependent chemiluminescence, a measure of reactive oxygen species (ROS) formation, generated by BAL cells was monitored and the levels of nitric oxide and tumor necrosis factor (TNF)-[alpha] produced by macrophages in culture were determined. At 7 days postinfection, we excised the lung-draining lymph nodes and phenotyped the lymphocyte subpopulations. Exposure of rats to DEP, but not to CB, decreased the clearance of Listeria from the lungs. Listeria-induced generation of luminol-dependent chemiluminescence by pulmonary phagocytes decreased by exposure to DEP but not CB. Similarly, Listeria-induced production of NO by alveolar macrophages was negated at 3, 5, and 7 days after inoculation in DEP-exposed rats. In contrast, CB exposure had no effect on Listeria-induced NO production at 3 days after infection and had a substantially smaller effect than DEP at later days. Exposure to DEP or CB resulted in enlarged lung-draining lymph nodes and increased the number and percentage of CD4(+) and CD8(+) T cells. These results showed that exposure to DEP decreased the ability of macrophages to produce antimicrobial oxidants in response to Listeria, which may play a role in the increased susceptibility of rats to pulmonary infection. This DEP-induced suppression is caused partially by chemicals adsorbed onto the carbon core of DEP, because impaired macrophage function and decreased Listeria clearance were not observed following exposure to CB.

A cell-based drug delivery system for lung targeting: II. Therapeutic activities on B16-F10 melanoma in mouse lungs

The in vitro and in vivo anticancer activities of doxorubicin-loaded B16-F10 murine melanoma cells (DLTC) were evaluated. DLTC showed similar growth-inhibitory effects against live B16-F10 cells with doxorubicin solution in cell culture system, with the IC50 of 0.11 microM and 0.17 microM, respectively. However, DLTC demonstrated higher effectiveness than the free solution in treating mouse lung cancer caused by live B16-F10 cells. Syngeneic C57BL mice were inoculated intravenously with live B16-F10 cells first, and then received daily treatment of intravenous injections of doxorubicin in either DLTC or free solution form. Compared with the control group treated with phosphate-buffered saline, DLTC eradicated almost all the lung cancer colonies (>99%), while the free solution form reduced the colonies by 61%, when the treatment was given at an early stage. If the treatment started after the establishment of micrometastatic colonies in the mouse lungs, DLTC and free solution treatment resulted in 85% and 30% cancer reduction, respectively. Additional experiments demonstrated that the reduction of lung cancer colonies by DLTC was related to the initial treatment time: the earlier the treatment, the greater the effect. In conclusion, DLTC showed better therapeutic outcomes than free solution form in treating lung cancer of our animal model.

A cell-based drug delivery system for lung targeting: I. Preparation and pharmacokinetics

A drug-loaded tumor cell (DLTC) system has been developed for lung metastasis-targeting drug delivery. Doxorubicin was loaded into B16-F10 murine melanoma cells (96 microg/10(6) cells). The loading process led to the death of all the carrier cells. The diameter of DLTC was 15.03+/-2.36 microm (mean +/- SD). The amount and rate of doxorubicin being released from the DLTC mainly depended on the drug loading and carrier cell concentration. Over a 6-month storage in phosphate buffered saline (PBS) at 4 degrees C, the decrease in intracellular drug concentration and the carrier cell number were less than 25% and 5%, respectively. After a bolus injection of 30 microg doxorubicin in either DLTC form or free solution into the mice tail veins, drug deposit in the lung from DLTC was 3.6-fold of that achieved by free drug solution. The latter resulted in higher drug content in liver and spleen. Extensive trypsinization of DLTC reduced its lung targeting effect by 30%, and the density of surface adhesion molecule GM3 on DLTC surface by 25%. In conclusion, this DLTC system demonstrated a lung-targeting activity that may be partially attributed to its specific surface characteristics.

Assembly and plasma membrane targeting of recombinant immunoglobulin chains in plants with a murine immunoglobulin transmembrane sequence

The cDNA encoding a full-length murine immunoglobulin gamma 1 heavy chain with its native leader sequence, transmembrane and intracellular domains was introduced into transgenic plants. Transformed plants expressed the recombinant polypeptide, but, in contrast to plants expressing the heavy chain without transmembrane sequence, the protein appeared to be associated with a plant cell membrane. Extraction of the membrane-associated heavy chain required the presence of a non-ionic detergent, and immunofluorescence studies of protoplasts demonstrated surface expression of membrane Ig heavy chain on up to 40% of the cells from a transgenic leaf. In plants expressing both the membrane Ig heavy chain and its partner light chain, functional antibody was also localised to the plant cell membrane and retention of the heavy chain at this site appeared to have no effect on the efficiency of antibody assembly. This approach of localising and accumulating recombinant antibody in cell membranes may have a number of applications, including passive immunisation against plant pathogens.

Immunoglobulin responses to experimental silicosis

Silicosis is a crippling fibrotic lung disease induced by inhalation of crystalline silica. One feature of silicosis is systemic and pulmonary immune dysfunction characterized in part by elevations in serum and bronchoalveolar lavage (BAL) immunoglobulins. A major specific aim of the current report was to demonstrate that an experimental model of silicosis previously well characterized for the development of pulmonary inflammation and fibrosis would also exhibit increased levels of serum and BAL IgG and IgM similar to those of human silicosis. We also sought to document the anatomic compartments responsible for these immunoglobulin responses. To address these specific aims, we compared levels of IgG and IgM in serum and BAL from rats with experimental silicosis induced by inhalation of silica with levels of these immunoglobulins in titanium dioxide (TiO(2))- and sham (air)-exposed controls. The ability of mononuclear cell populations from lung, lung-associated lymph node, and spleen to produce IgG and IgM ex vivo were also compared. We found that experimental silicosis was associated with elevated IgG and IgM levels in blood and BAL relative to the control groups. Our findings also suggested that draining lung-associated lymph nodes (LALN) were the most important sites for increased IgG and IgM production in experimental silicosis, with lungs contributing to a lesser degree. Increased production in the LALN appeared related to marked expansion in total numbers, but not relative proportion, of B lymphocytes.

Assembly, secretion, and vacuolar delivery of a hybrid immunoglobulin in plants

Secretory immunoglobulin (Ig) A is a decameric Ig composed of four alpha-heavy chains, four light chains, a joining (J) chain, and a secretory component (SC). The heavy and light chains form two tetrameric Ig molecules that are joined by the J chain and associate with the SC. Expression of a secretory monoclonal antibody in tobacco (Nicotiana tabacum) has been described: this molecule (secretory IgA/G [SIgA/G]) was modified by having a hybrid heavy chain sequence consisting of IgG gamma-chain domains linked to constant region domains of an IgA alpha-chain. In tobacco, about 70% of the protein assembles to its final, decameric structure. We show here that SIgA/G assembly and secretion are slow, with only approximately 10% of the newly synthesized molecules being secreted after 24 h and the bulk probably remaining in the endoplasmic reticulum. In addition, a proportion of SIgA/G is delivered to the vacuole as at least partially assembled molecules by a process that is blocked by the membrane traffic inhibitor brefeldin A. Neither the SC nor the J chain are responsible for vacuolar delivery, because IgA/G tetramers have the same fate. The parent IgG tetrameric molecule, containing wild-type gamma-heavy chains, is instead secreted rapidly and efficiently. This strongly suggests that intracellular retention and vacuolar delivery of IgA/G is due to the alpha-domains present in the hybrid alpha/gamma-heavy chains and indicates that the plant secretory system may partially deliver to the vacuole recombinant proteins expected to be secreted.

A murine monoclonal antibody produced in transgenic plants with plant-specific glycans is not immunogenic in mice

Previous studies have shown that the production of recombinant antibodies in plants is highly efficient and presents numerous therapeutic applications. It is, however, known that plant glycoproteins display different glycosylation patterns to those exhibited by mammalian glycoproteins. Thus, it is important to know if these plant recombinant antibodies could induce undesirable immune responses in mammals; and to date no report has documented the potential immunogenicity of parenterally administered plant recombinant antibodies in animals. In order to answer this question, mice were immunised subcutaneously with a recombinant mouse monoclonal antibody produced in tobacco plants, together with alum as adjuvant. Two control groups were immunised in the same way with either the original murine monoclonal antibody or horseradish peroxidase (a plant glycoprotein). Analyses by direct immunoassay, competition immunoassay and real-time surface plasmon resonance, showed undetectable levels of antibody directed against both the protein and the glycan part of the plant recombinant antibody. These results have a direct relevance for the application of plant recombinant proteins as therapeutic agents and vaccines in humans.

Detection of bacterial virulence genes associated with infective endocarditis in infected root canals

AIM

The aim of this study was to examine whether bacteria associated with root canals possess genes that might predispose to bacterial colonization of the endocardium.

METHODOLOGY

Oligonucleotides were designed from DNA sequences encoding the functional binding regions of streptococcal fibronectin-binding protein (FnBP) and staphylococcal fibrinogen-binding protein (FgBP). The specificity and cross-reactivity of the oligonucleotide primers were investigated; streptococcal primers were tested for recognition of FnBP genes in other strains of streptococci, and the staphylococcal primers for detection of FgBP from other staphylococci. Interspecies specificity of these primers was also investigated. In a pilot clinical study, the pulp chambers of 16 nonvital teeth without sinus tracts, were opened aseptically. Root canal samples were collected, along with samples from the gingival sulcus and anterior nares. From these samples DNA was extracted, subjected to polymerase chain reaction (PCR) and analysed by agarose gel electrophoresis.

RESULTS

Using the streptococcal FnBP primers, PCR bands were amplified from eight root canal samples, eight gingival samples and three nasal samples. With the staphylococcal primers, PCR bands were amplified from seven root canals, 11 gingival and nine nasal samples. This study showed that PCR could be used to detect bacteria in root canals that possess genes with homology to functional regions of those encoding FnBP or FgBP.

CONCLUSIONS

If bacteria in root canals possess FnBP or FgBP, they may have the potential to cause infective endocarditis.

Characterization of proteolytic activities of pulmonary alveolar epithelium

Pulmonary alveolar type I epithelial cell and its progenitor, type II cell, present major transport and enzyme barriers for systemic delivery of pulmonary administered peptide drugs. The present study investigates the effect of cellular differentiation of type II to type I cells on their proteolytic activities, and evaluates the suitability of a continuous lung cell line, A549, for drug transport and degradation studies. High performance liquid chromatography was used to assess the degradation kinetics of two model peptide substrates, luteinizing hormone releasing hormone (LHRH) and [D-Ala(6)10-fold decrease in proteolytic activities for LHRH, as compared to type II cells. The continuous lung cell line A549 formed leaky monolayers and exhibited similar enzyme activities to the primary type II cells. The responsible enzymes for degradation of LHRH in type II and A549 cells were angiotensin converting enzyme (ACE), EP24.11, and EP24.15. In contrast, no EP24.15 or ACE activity was observed in type I-like pneumocytes and only a weak EP24.11 activity was detected. In all cell types, the degradation rate of [D-Ala(6)]-LHRH was about 3-8 times lower than that of LHRH. This peptide analog was resistant to degradation by EP24.15 and EP24.11, but was susceptible to ACE-mediated cleavage.

Effects of diesel exhaust particles (DEP), carbon black, and silica on macrophage responses to lipopolysaccharide: evidence of DEP suppression of macrophage activity

The effects of diesel exhaust particle (DEP) exposure on alveolar macrophage (AM) response to ex vivo and in vivo lipopolysaccharide (LPS) challenge were determined by monitoring LPS-stimulated production of interleukin-1 (IL-1) and tumor necrosis factor-alpha (TNF-alpha). The roles of the insoluble particulate and the organic compounds of DEP in altering pulmonary responses were evaluated by comparing the DEP-induced pulmonary responses to those of carbon black (CB), a carbonaceous particle with few adsorbed organic compounds, or to silica, a known pneumotoxic dust. Male Sprague-Dawley rats were exposed to a single intratracheal dose (5 or 35 mg/kg body weight) of DEP, CB, or silica, or to saline vehicle. Rats were sacrificed 1, 3, or 7 d postexposure. To study the responsiveness to the bacterial product LPS, AM isolated from particle-exposed rats were challenged ex vivo with LPS (0.1 microg/10(6) AM) and LPS-stimulated cytokine release was monitored. In addition, rats were exposed intratracheally to a single dose of DEP (5 mg/kg) and 3 d later exposed in vivo to 1 mg/kg LPS for 3 h prior to measurement of cytokine production by AM. DEP exposure resulted in neutrophil infiltration and elevated levels of albumin and lactate dehydrogenase (LDH) activity in the bronchoalveolar lavage fluid; these responses were not substantially different from those elicited by CB or silica exposure. AM from DEP-exposed rats showed increased spontaneous production of IL-1, but not TNF-alpha, while the opposite was true for CB or silica. Upon ex vivo challenge with LPS, AM from DEP-exposed rats showed a significant decrease in the secretion of TNF-alpha and, to a lesser extent, IL-1, compared to the sum of the DEP and LPS effects. In contrast, AM from CB- or silica-exposed rats did not show this decreased responsiveness to subsequent LPS challenge. This inhibitory action of DEP on LPS-stimulated AM production of IL-1 and TNF-alpha was further confirmed by the results obtained from rats exposed to both DEP and LPS in vivo. In summary, these results indicate that while DEP, CB, and silica all induce pulmonary inflammatory responses due to particle stimulation, only DEP suppress AM cytokine release in response to LPS stimulation. The contrasting cellular response with respect to DEP and CB exposures may be due to the presence of adsorbed organic compounds on DEP, which may contribute to the increased susceptibility of hosts to pulmonary infections after DEP exposure.

The caries vaccine: a growing prospect

A vaccine against dental caries, for so long a subject of purely academic research, is currently undergoing phase II clinical trials and could be available commercially within 5 to 6 years. The approach, which is safe, effective, and provides long-term protection for up to a year, is based on a topical application and does not require any injections. The development of this vaccine has been made possible by recent advances in molecular biology and genetic engineering. Perhaps one of the most intriguing aspects has been the use of green plants to produce the vaccine. This article describes a topical vaccine against Streptococcus mutans, which is the main cause of dental caries.

Use of tetrandrine to differentiate between mechanisms involved in silica-versus bleomycin-induced fibrosis

Animals exposed to silica or bleomycin (BLM) develop pulmonary fibrosis. Tetrandrine (TT) has been shown to inhibit stimulant-induced macrophage respiratory burst and effectively reduce silica-induced lung injury. The present study employed TT as a probe to assess the differences in mechanisms involved in silica- and BLM-induced pulmonary responses. Rats received a single intratracheal instillation of silica (40 mg/rat, sacrificed 4 wk postexposure) or BLM (1 mg/kg or approximately 0.25 mg/rat, sacrificed up to 2 wk postexposure). TT was administered orally at 18 mg/kg, 3 times/wk for desired time periods beginning 5 d before silica or BLM exposure. Both the silica and BLM exposures resulted in a significant increase in lung weight, total protein, lactate dehydrogenase (LDH), and phospholipids (PL) content in the acellular fluid from the first lavage, and hydroxyproline content in the lung tissue. Alveolar macrophages (AM) isolated from rats exposed to silica or BLM exhibited significant increases in secretion of interleukin-1 (IL-1), tumor necrosis factor alpha (TNF-alpha), and transforming growth factor beta (TGF-beta). TT treatment significantly lowered the silica- or BLM-induced increase in lung weight, while marginally reducing the release of IL-1 and TNF-alpha by AM. TT, however, markedly inhibited the silica-induced increase in the acellular protein, LDH and PL, hydroxyproline content, and the production of TGF-beta by AM but had no marked effect on these same parameters in BLM-exposed rats. Histological examination of rats exposed to BLM for 14 d showed pulmonary inflammation and fibrosis. TT treatment had only a small effect on limiting the extent of these lesions and did not significantly affect their severity. In summary, data indicate that many inflammatory and fibrotic effects of in vivo silica exposure are substantially attenuated by TT, whereas the stimulation by BLM is only marginally affected by this drug. Since TT acts to attenuate AM-mediated reactions, these results suggest that AM may play a pivotal role in silica-induced fibrotic development and may be less involved in the pathogenesis of BLM-induced fibrosis.

N-Glycosylation of a mouse IgG expressed in transgenic tobacco plants

Since plants are emerging as an important system for the expression of recombinant glycoproteins, especially those intended for therapeutic purposes, it is important to scrutinize to what extent glycans harbored by mammalian glycoproteins produced in transgenic plants differ from their natural counterpart. We report here the first detailed analysis of the glycosylation of a functional mammalian glycoprotein expressed in a transgenic plant. The structures of the N-linked glycans attached to the heavy chains of the monoclonal antibody Guy's 13 produced in transgenic tobacco plants (plantibody Guy's 13) were identified and compared to those found in the corresponding IgG1 of murine origin. Both N-glycosylation sites located on the heavy chain of the plantibody Guy's 13 are N-glycosylated as in mouse. However, the number of Guy's 13 glycoforms is higher in the plant than in the mammalian expression system. Despite the high structural diversity of the plantibody N-glycans, glycosylation appears to be sufficient for the production of a soluble and biologically active IgG in the plant system. In addition to high-mannose-type N-glycans, 60% of the oligosaccharides N-linked to the plantibody have beta(1, 2)-xylose and alpha(1, 3)-fucose residues linked to the core Man3GlcNAc2. These plant-specific oligosaccharide structures are not a limitation to the use of plantibody Guy's 13 for topical immunotherapy. However, their immunogenicity may raise concerns for systemic applications of plantibodies in human.

A synthetic peptide adhesion epitope as a novel antimicrobial agent

The earliest step in microbial infection is adherence by specific microbial adhesins to the mucosa of the oro-intestinal, nasorespiratory, or genitourinary tract. We inhibited binding of a cell surface adhesin of Streptococcus mutans to salivary receptors in vitro, as measured by surface plasmon resonance, using a synthetic peptide (p1025) corresponding to residues 1025-1044 of the adhesin. Two residues within p1025 that contribute to binding (Q1025, E1037) were identified by site-directed mutagenesis. In an in vivo human streptococcal adhesion model, direct application of p1025 to the teeth prevented recolonization of S. mutans but not Actinomyces, as compared with a control peptide or saline. This novel antimicrobial strategy, applying competitive peptide inhibitors of adhesion, may be used against other microorganisms in which adhesins mediate colonization of mucosal surfaces.

Enzymatic degradation of luteinizing hormone releasing hormone (LHRH)/[D-Ala6]-LHRH in lung pneumocytes

PURPOSE

To investigate the cellular proteolytic activities of various lung pneumocytes using luteinizing hormone releasing hormone (LHRH) and [D-Ala6]-LHRH as model peptide substrates.

METHODS

HPLC analysis was used to investigate the degradation kinetics of LHRH/[D-Ala6]-LHRH and to identify their degradation products in isolated lung pneumocytes.

RESULTS

Pulmonary macrophages exhibited the strongest proteolytic activity against LHRH)/[D-Ala6]-LHRH, followed by type II and type I-like pneumocytes. Three major degradation products of LHRH, namely LHRH 4-10, LHRH 6-10, and LHRH 7-10, were identified in macrophages and type II pneumocytes, whereas in type I-like pneumocytes only the LHRH 7-10 was found. Co-incubation of the cells with known enzyme inhibitors including captopril (an ACE inhibitor), thiorphan (an EP24.11 inhibitor), and EDTA (an EP24.15 inhibitor) inhibited the formation of LHRH 4-10, LHRH 7-10, and LHRH 6-10 respectively. In all cell types, the degradation rate of [D-Ala6]-LHRH was about 3-8 times lower than that of LHRH. This peptide analog was resistant to degradation by EP24.15 and EP24.11, but was susceptible to ACE.

CONCLUSIONS

ACE, EP24.11, and EP24.15 are the major enzymes responsible for the degradation of LHRH in macrophages and type II pneumocytes. The magnitude of peptidase activities in these cell types are: EP24.15 > EP24.11 approximately ACE. No EP24.15 or ACE activity was observed in type I-like pneumocytes and only a weak EP24.11 activity was detected.

Characterization of a recombinant plant monoclonal secretory antibody and preventive immunotherapy in humans

A functional comparison was made between a monoclonal secretory antibody generated in transgenic plants and its parent murine IgG antibody.The affinity constants of both antibodies for a Streptococcus mutans adhesion protein were similar. However the secretory antibody had a higher functional affinity due to its dimeric structure. In the human oral cavity, the secretory antibody survived for up to three days, compared with one day for the IgG antibody. The plant secretory antibody afforded specific protection in humans against oral streptococcal colonization for at least four months. We demonstrate that transgenic plants can be used to produce high affinity, monoclonal secretory antibodies that can prevent specific microbial colonization in humans. These findings could be extended to the immunotherapeutic prevention of other mucosal infections in humans and animals.

Effects of diesel exhaust particles on the release of interleukin-1 and tumor necrosis factor-alpha from rat alveolar macrophages

The effects of diesel exhaust particles (DEP) and their components (washed dust and methanol extracts) on the release of proinflammatory cytokines, interleukin-I (IL-1), and tumor necrosis factor-alpha (TNF-alpha) by alveolar macrophages (AM) were investigated. Rat AM were incubated with 0, 5, 10, 20, 50, or 100 micrograms/10(6) AM/mL of DEP, methanol-washed DEP, or equivalent concentrations of DEP methanol extracts at 37 degrees C for 24 h. AM-conditioned supernatants were collected and assayed for the activities of IL-1 and TNF-alpha. At high concentrations both DEP and DEP methanol extracts were shown to increase IL-I-like activity secreted by AM, whereas methanol-washed DEP had no effect. Neither DEP, methanol-washed DEP, nor DEP methanol extracts was found to stimulate the secretion of TNF-alpha. The effects of DEP on the release of IL-I and TNF-alpha by lipopolysaccharide (LPS)- or interferon-gamma (IFN-gamma)-primed AM were also studied. AM were preincubated with various concentrations of DEP for 2 h, then challenged with either 0.1 microgram/mL of LPS or 5 units/mL of IFN-gamma. DEP inhibited LPS-stimulated production of H-I and TNF-alpha. These inhibitory effects were attributed to the organic extracts of DEP. In contrast, stimulation of AM production of TNF-alpha by IFN-gamma was not affected by DEP exposure. In summary, evidence that DEP enhanced the production of IL-1 by AM in vitro suggests that this proinflammatory cytokine may play a role in the pulmonary response to DEP inhalation. The suppressive response of DEP-pretreated AM to LPS stimulation may be a contributing factor to the impairment of pulmonary defense system after prolonged DEP exposure.

Antisense inhibition of silica-induced tumor necrosis factor in alveolar macrophages

Tumor necrosis factor-alpha (TNFalpha) has been shown to play an important role in the pathogenesis of silicotic fibrosis. In this study, antisense oligonucleotides targeted to TNFalpha mRNA were used to inhibit silica-induced TNFalpha gene expression in alveolar macrophages. To achieve macrophage-specific oligonucleotide delivery, a molecular conjugate consisting of mannosylated polylysine that exploits endocytosis via the macrophage mannose receptor was used. Complexes were formed between the mannosylated polylysine and oligonucleotides and added to the cells in the presence of silica. Enzyme-linked immunoadsorbent assay showed that the complex consisting of the conjugate and antisense oligomer effectively inhibited TNFalpha production, whereas the oligomer alone had much less effect. Reverse transcriptase-polymerase chain reaction analysis revealed that the reduction in TNFalpha secretion was associated with specific ablation of targeted TNFalpha mRNA. The conjugate alone or conjugate complexed with inverted or sense sequence oligonucleotide had no effect. The promoting effect of the conjugate on antisense activity was shown to be due to enhanced cellular uptake of the oligomer via mannose receptor-mediated endocytosis. Cells lacking mannose receptors showed no susceptibility to the conjugate treatment. These results indicate that effective and selective inhibition of macrophage TNFalpha expression can be achieved using the antisense mannosylated polylysine system.

Studies on the mutagenicity of mild gasification products of coal and their subfractions by the Salmonella/microsomal assay

Mild gasification of coal is a technology being developed in the United States in order to upgrade lower rank coals and facilitate their use in coal-burning electric generation plants. Thirteen coal-derived mild gasification products from different coal sources and processing conditions have been examined for their potential biohazards. The mutagenicity of these samples was tested with the Ames Salmonella/microsomal assay. Two solvents, dimethyl sulfoxide (DMSO) and polyoxyethylene-sorbitan monooleate (Tween 80), were used to dissolve samples in a manner to facilitate their interaction with the test organisms. The results showed that 9 of the 13 samples displayed mutagenic activity in test strains TA98 and/or TA100 with or without metabolic activation, whether dissolved in Tween 80 or DMSO. Five mutagenic and two nonmutagenic samples were class-fractionated into basic, acidic, nonpolar, and polar neutral subfractions to examine their class-related mutagenic activities. Results of the testing of subfractions of the five mutagenic and one nonmutagenic samples showed mutagenic activity in at least the nonpolar neutral fraction. The subfractions of the another nonmutagenic sample did not display any mutagenic activity. Chemical characterization of the subfractions revealed the existence of aromatic hydrocarbons in certain subfractions, which may be responsible for the mutagenic activity of the coal-derived mild gasification products.

Reduction of lung dust burden in pneumoconiosis by whole-lung lavage

Pneumoconioses are characterized as irreversible, progressive respiratory diseases. No effective therapy exists to prevent progression of these diseases. Whole-lung lavage (WLL) might limit the rate of disease progression through the removal of dust, inflammatory cells, and cytokines. We performed WLL on a 54-year-old underground miner employed as a motorman and roof bolter and a 55-year-old driller at a surface coal mine. Both demonstrated normal lung function and chest radiographs showing ILO profusion category 2 nodular interstitial changes. From Subject 1, we recovered 5.24 x 10(8) cells (90% macrophages) from the right lung and 3.45 x 10(8) cells (94% macrophages) from the left lung. WLL removed 1.82 g of mineral dust (non-coal) on the right and 1.64 g on the left. From Subject 2, we recovered 7.49 x 10(8) cells (46% macrophages) from the right and 9.78 x 10(8) cells (69% macrophages) from the left lung. WLL removed 0.40 g of mineral dust on the right and 0.53 g on the left. Proinflammatory cytokines, growth factors, and cellular enzymes were also recovered. In cases of pneumoconiosis, WLL is capable of removing relatively large quantities of dust, cells, and soluble materials from the lungs. Only long-term follow-ups of individuals with progressive dust-induced disease who receive WLL therapy in the context of a clinical trial will provide information regarding the importance of removing mineral dust and inflammatory cells from the lung.

Antibody production and engineering in plants

Plants have always been important in the pharmaceutical industry, and plant biotechnology now offers new applications. The use of heterologous expression systems for production of recombinant proteins including antibodies is no longer novel. Attention has now turned towards the end-user, and specifically to engineering the antibody to precise requirements. In expanding the choice of production systems, plants offer unique alternatives for antibody users not only in the bulk production of antibody molecules but also in the ability to assemble full-length and complex, multimeric antibodies. Although the initial investment of time and effort is substantial compared to that of other expression systems, antibody production on an agricultural scale can be envisioned, and the economy of this approach opens many new areas for potential antibody applications in addition to their traditional research and pharmaceutical uses.