[Metagenomic data-analysis reveals enrichment of lipopolysaccharide synthesis in the gut microbiota of atrial fibrillation patients]

Objective: To investigate the functional changes of key gut microbiota (GM) that produce lipopolysaccharide (LPS) in atrial fibrillation (AF) patients and to explore their potential role in the pathogenesis of AF. Methods: This was a prospective cross-sectional study. Patients with AF admitted to Beijing Chaoyang Hospital of Capital Medical University were enrolled from March 2016 to December 2018. Subjects with matched genetic backgrounds undergoing physical examination during the same period were selected as controls. Clinical baseline data and fecal samples were collected. Bacterial DNA was extracted and metagenomic sequencing was performed by using Illumina Novaseq. Based on metagenomic data, the relative abundances of KEGG Orthology (KO), enzymatic genes and species that harbored enzymatic genes were acquired. The key features were selected via the least absolute shrinkage and selection operator (LASSO) analysis. The role of GM-derived LPS biosynthetic feature in the development of AF was assessed by receiver operating characteristic (ROC) curve, partial least squares structural equation modeling (PLS-SEM) and logistic regression analysis. Results: Fifty nonvalvular AF patients (mean age: 66.0 (57.0, 71.3), 32 males(64%)) were enrolled as AF group. Fifty individuals (mean age 55.0 (50.5, 57.5), 41 males(82%)) were recruited as controls. Compared with the controls, AF patients showed a marked difference in the GM genes underlying LPS-biosynthesis, including 20 potential LPS-synthesis KO, 7 LPS-biosynthesis enzymatic genes and 89 species that were assigned as taxa harbored nine LPS-enzymatic genes. LASSO regression analysis showed that 5 KO, 3 enzymatic genes and 9 species could be selected to construct the KO, enzyme and species scoring system. Genes enriched in AF group included 2 KO (K02851 and K00972), 3 enzymatic genes (LpxH, LpxC and LpxK) and 7 species (Intestinibacter bartlettii、Ruminococcus sp. JC304、Coprococcus catus、uncultured Eubacterium sp.、Eubacterium sp. CAG:251、Anaerostipes hadrus、Dorea longicatena). ROC curve analysis revealed the predictive capacity of differential GM-derived LPS signatures to distinguish AF patients in terms of above KO, enzymatic and species scores: area under curve (AUC)=0.957, 95%CI: 0.918-0.995, AUC=0.940, 95%CI 0.889-0.991, AUC=0.972, 95%CI 0.948-0.997. PLS-SEM showed that changes in lipopolysaccharide-producing bacteria could be involved in the pathogenesis of AF. The key KO mediated 35.17% of the total effect of key bacteria on AF. After incorporating the clinical factors of AF, the KO score was positively associated with the significantly increased risk of AF (OR<0.001, 95%CI:<0.001-0.021, P<0.001). Conclusion: Microbes involved in LPS synthesis are enriched in the gut of AF patients, accompanied with up-regulated LPS synthesis function by encoding the LPS-enzymatic biosynthesis gene.

[The clinical application of mobile internet remote guidance platform for vestibular rehabilitation]

Objective: To guide the patients with vertigo who are suitable for vestibular rehabilitation therapy (VRT), and to evaluate the curative effect through a remote guidance platform based on mobile internet. Methods: Adult outpatients, who were diagnosed as vestibular disorders and required VRT, were selected and conducted baseline evaluation and formulated vestibular rehabilitation plan according to their symptoms, diagnosis and vestibular function examination results. These patients downloaded and installed the mobile internet remote guidance platform app for VRT, and then registered and uploaded medical records. According to the VRT plan formulated by clinicians for patients, the platform launched corresponding exercise guidance videos to guide them to complete 4-week VRT exercise at home. Before and after VRT, the patients were scored with Visual Analogue Scale (VAS), Activities-specific Balance Confidence (ABC), Dizziness Handicap Inventory (DHI) and Self-rating Anxiety Scale (SAS). The rehabilitation effects were statistically analyzed by SigmaStat 4.0 software. Results: From October 2019 to October 2021, 233 patients with vertigo completed the registration of vestibular rehabilitation guidance platform, of whom 187 patients insisted on 4-week rehabilitation training and completed the scale evaluation. Among 187 patients, 65 were male and 122 were female; Age was (49.8±16.0) years; The medical history ranged from one to 192 months, with a median of eight months. Compared with that before rehabilitation exercise, the subjective feeling of vertigo in 170 patients was improved, and the overall effective rate was 90.9% (170/187). The subjective symptoms of vertigo were basically improved after rehabilitation training in patients with unilateral vestibular dysfunction, vestibular neuritis, sudden deafness with vertigo, Hunt syndrome and acoustic neuroma. There were significant differences in ABC, DHI and SAS scores before and after VRT (P<0.05). Of those patients with Meniere's disease in the intermittent period and the patients with Meniere's disease who underwent surgical treatment, more than 90% of their subjective symptoms of vertigo or dizziness improved after VRT, and there were significant differences in the scores of ABC, DHI and SAS before and after VRT exercise (P<0.05). In patients with vestibular migraine, 36.7% (11/30) had no improvement or even aggravation of subjective symptoms of vertigo after VRT, however, the DHI score after rehabilitation exercise was lower than that before exercise, and the difference was statistically significant (P<0.05). In patients with bilateral vestibular dysfunction, although most (6/8) subjective symptom scores were improved compared with those before exercise, there was no significant difference in ABC, DHI and SAS scores before and after rehabilitation (P>0.05). Conclusion: VRT with the help of vestibular rehabilitation mobile internet remote guidance platform can effectively improve the subjective symptoms of vertigo, balance ability and anxiety in patients with unilateral vestibular lesions.

[Epidemiological characteristics of influenza and characteristics of hemagglutinin gene of B-Victoria strains in Hebei Province from 2018 to 2019]

Objective: To understand the epidemiological characteristics of influenza in Hebei Province from 2018 to 2019, and to analyze the characteristics and variation of hemagglutinin(HA) gene of influenza B-Victoria(BV) strains. Methods: Throat swab specimens of influenza-like cases within 3 days of fever were collected from 28 sentinel hospitals in Hebei province, meanwhile, The surveillance data was collected by the Chinese National Influenza Surveillance Network from April 2018 to March 2019, Throat swab specimens were collected from patients with influenza-like symptoms in sentinel hospitals, and tested by RT-PCR and virus isolation. 14 influenza B-Victoria strains from different regions were selected to sequence HA gene, Phylogenetic tree and the molecular characteristics were analyzed by DNASTAR 7.0 and Mega-X software. Results: From 2018 to 2019, A total of 99 266 cases of influenza-like illness (ILI) were detected from 4 689 103 cases by 28 influenza sentinel hospitals in Hebei Province, the visit percentage of ILI was 2.12%. During the period, 18 730 samples were detected, and 2 752(14.69%) samples were positive tested by RT-PCR, the peak was in the third week of 2019(44.92%), In the early stage of epidemic season, Influenza A(H1N1)pdm09 virus was the main type, while BV virus was the main type in the late stage. HA gene sequence analysis showed that the 14 BV viruses belonged to 162-164 amino acid deletion strains, the amino acid homology between HA sequences was 97.16%-100.00%, and 97.16%-98.95% compared with the vaccine strain B/Colorado/06/2017 recommended by WHO. Compared with the vaccine strains, 14 strains involved 11 amino acid site mutations. Conclusion: Influenza was prevalent in winter and spring in Hebei province from 2018 to 2019, Multiple mutations in antigenic sites of BV viruses might be related to the outbreaks.

[Effects of duodenal ligation on gastroesophageal reflux and bleomycin-induced pulmonary fibrosis in rats]

Objective: To investigate the effects of duodenal ligation on gastroesophageal reflux and bleomycin-induced pulmonary fibrosis in rats. Methods: Wistar rats were randomized into the control (Ctrl) group, bleomycin (BLM) group, duodenal ligation (GER) group and duodenal ligation plus bleomycin treatment (BLM+GER) group. At day 0 (d0), duodenum ligation was performed in the GER and the BLM+GER group through an open-abdomen surgery at 1.0 cm below the pylorus by about 30% of the circumference. Meanwhile, sham operation was performed in the Ctrl and the BLM group with similar procedures to the above without ligation of the duodenum. At day 14, bleomycin solution (5 mg/kg, for the BLM and BLM+GER groups) or saline (for the Ctrl and GER groups) was intratracheally instilled. Rats were sacrificed at d28 or at d42. HE, Masson's trichrome or TUNEL staining was performed on lung sections of the groups. The levels of hyrdoxyproline (HYP) or malondialdehyde (MDA) were measured respectively by alkaline hydrolysis or thiobarbituric acid colorimetry. The levels of pepsin and cytokines in bronchoalveolar lavage fluid (BALF) samples were assessed by ELISA. Western blot or RT-PCR was used to quantify relative lung expression of proteins or mRNA, respectively. Results: Lungs of the GER group rats were presented with mild inflammatory cell infiltration. Alveolitis and lung fibrosis was prominent in the BLM group but even more severe in the BLM+GER group. Of the Ctrl, GER, BLM and BLM+GER group, the average numbers of apoptotic cells per each magnified field (×200) on d28 lung sections was (5.6±3.0), (6.4±5.3), (15.4±5.3) and (18.4±9.1), respectively (P=0.008); the proportion (%) of blue-stained area under Masson's trichrome at d42 was (21.5±2.8), (23.4±2.5), (34.0±5.8) and (41.3±2.9) (P<0.05); the HYP contents (mg/L) at d42 of each group was (0.77±0.01), (1.26±0.01), (2.02±0.01) and (2.39±0.01) (P<0.01); the BALF levels of MDA (μmol/L) at d42 were (0.51±0.09), (0.87±0.12), (1.40±0.31) and (1.71±0.12) (P<0.001), and differences of these three indices at d42 reached statistical significance when comparing the Ctrl or GER group with the BLM or BLM+GER group (all P<0.05). The levels of pepsin, pH, interleukin (IL)-1β, transforming growth factor (TGF)-β1 and HYP at d28 and d42 were statistically different between the GER group and the Ctrl group (all P<0.05). As compared with the BLM group, the values of TGF-β1, HYP, p-Smad3, vimentin, p-ERK1/2 and cleaved caspase-3 at d28 and d42 were different in the BLM+GER group (all P<0.05). At both d28 and d42, the BALF levels of pepsin and pH were statistically different between the BLM and the Ctrl group, or between the BLM+GER group and the GER group (all P<0.05). Conclusions: Gastroesophageal reflux is induced through duodenal ligation, which activates proinflammatory and profibrotic signals in the lungs and significantly aggravates bleomycin-induced lung injury and fibrosis. In addition, pulmonary fibrosis may induce or worsen the extent of reflux.

[Progress in the diagnosis and treatment of oropharyngeal cancer]

SummaryIn recent years，human papillomavirus has been proved to be closely related to the occurrence and prognosis of oropharyngeal cancer.The treatment of oropharyngeal cancer has evolved from the primary radiotherapy to the corresponding treatment according to different tumor stages.For patients with advanced oropharyngeal cancer，the treatment strategy is mostly surgery + postoperative concurrent chemoradiotherapy.Patients are often accompanied by large defects in the surgical area after surgery.With the improvement of head and neck surgical repair technology and the progress of free flap technology，various repair methods can be adopted to repair and reconstruct.

[Diagnosis and treatment of cervical migratory foreign bodies caused by sharp esophageal foreign bodies]

Objective:Imaging findings and treatment of sharp foreign bodies penetrating the esophagus to migrate in the neck were collected. Method:All of 9 cases were determined by CT imaging. The foreign bodies were removed in 8 cases through the lateral cervical approach. The last case was taken out by bronchoscope. Eight cases successfully removed the foreign bodies. No definite foreign body was found in 1 case. Result:There were no postoperative complications in 8 patients that successful removed of foreign bodies. All patients begin to eat normally after operation and were discharged from hospital in 7 days. Tracheoesophageal fistula occurred that happened to the patient that no foreign body was found in operation. So gastric tube was retained for 7 days. Conclusion:CT imaging should be performed to determine whether there is the possibility of foreign body penetrating out of the esophagus, for the patients who had explicit history but the foreignbodies could not be found by barium meal examination. If necessary, three-dimensional CT reconstruction of the neck should be performed to locate the foreign body. Surgical exploration should be done as soon as possible to avoid aimless migration of foreign bodies, and it is difficult to find it during operation.

[Relationship between gH genotyping and clinical characteristics of children with congenital cytomegalovirus infection]

Objective: To study the relationship between human cytomegalovirus (HCMV) envelope glycoprotein gene H and clinical features of children with congenital cytomegalovirus infection. Methods: A cohort study was conducted. Newborns diagnosed with congenital cytomegalovirus infection, hospitalized in the Department of Neonatology and Neonatal Intensive Care Unit (NICU) of the Children's Hospital, Zhejiang University School of Medicine, were included from July 2013 to December 2015.HCMV-DNA gH typing in urine, sputum or blood was conducted. Patients then were divided into gH1 group and gH2 group according to gH genotypes. Patients' data during hospitalization in newborn and 3-5 years of follow-up were collected.The relationships between gH genotype and clinical manifestations, laboratory examinations, hearing loss and neurological prognosis were analyzed by chi-square test, t test and non-parametric test. Results: A total of 21 cases were enrolled as congenital HCMV infection and followed-up for 3-5 years. Among them, 14 (67%) were gH1 type and 7 (33%) were gH2 type. No mixed infection was found. In the two groups, there were no significant differences in the ratio of males (9/14 vs. 3/7,P=0.397), or birth weight ((2 609±686) vs. (3 021±451) g, t=-1.436, P=0.167). Gestational age of gH1 group was younger than that of gH2 group (38 (29-40) vs. 39(38-40) weeks, Z=-2.18, P=0.029). Moderate to severe hearing loss detected by neonatal auditory brainstem response were found in 40 ears (20 cases). It was higher in gH1 group than that in gH2 group (4/22 vs.0/18, χ(2)=5.145, P=0.023). In the imaging examination of the nervous system, the Alarcon score of gH1 group was lower than that of gH2 group (0.4±0.3 vs. 1.3±1.1, t=-2.459,P=0.024).No significant statistical difference was found in the probability of motor or language development lag in gH2 group and gH1 group (4/7 vs.4/14, P=0.346). Conclusions: Compared with gH2 infection, gH1 infection in children has a younger gestational age. The major type of hearing loss in neonatal period is gH1 infection. Children with gH2 congenital infections are more likely to suffer from nervous systems damage.

[Risk factors analyses for lateral neck lymph node metastasis in papillary thyroid carcinoma]

Objective:To study the risk factors for the lateral neck lymph node metastasis(LNM) in patients with papillary thyroid carcinoma(PTC).Method:Total 145 cases of papillary thyroid carcinoma patients were reviewed. These patients were divided into the following 2 groups: a lateral LNM-positive group and a lateral LNM-negative group.Clinical factors and tumor ultrasound characteristics were recorded, and the final pathology results were recorded as well. Result: Univariate and multivariate analyses indicated that primary tumor size(pathological diameter) >1.0 cm, upper portion location and lymph node metastasis in central neck were the three risk factors for lateral LNM of PTC(OR=6.250,4.881,5.222,P<0.05). The lymph node metastasis in the lateral neck was not correlated obviously with gender, age, capsuleinvasion, multifocality and tumor ultrasonic characteristics(including illdefined and irregular in shape, calcification, hypervascularized). The probability of lateral LNM was then calculated according to the number of risk factors present in each of the 145 patients, using the three factors. When two or more factors were present, the probability increased up to 38.1 %(95%CI23-53).Conclusion: The present study provides that lateral LNM occurs mainly in patients, with a tumor size(pathological diameter) diameter>1.0 cm, with the primary tumor located in the upper part of the lobe and positive central compartment lymph node metastasis. The risk increased up when at least two of the three factors were present. So it needs to pay attention to the high risk factors seriously which effect lateral neck lymph node metastasis in patients with PTC, combined with ultrasonic characteristics of lateral cervical lymph node or more meticulous evaluations, to establish the lymph node dissection individually.

[Clinical analysis of 234 esophageal foreign bodies]

Objective: To explore the clinical characteristics and treatment methods of esophageal foreign body. Method: The clinical data of 234 patients with esophageal foreign bodies admitted to our department from January 2015 to August 2018 were retrospectively analyzed, including course time, foreign body types, surgical methods, imaging manifestations and treatment related complications. Result: The diagnosis of esophageal foreign bodies was confirmed by esophageal CT or esophageal barium meal X-ray examination before operation in 234 patients. Course time varied from 3 hours to 7 days, and the jujube nucleus was the most common food-borne foreign body.223 patients underwent esophagoscopic exploration and foreign body removal under general intravenous anesthesia, 11 of them had no definite esophageal foreign body, 22 had esophageal perforation and periesophagitis. After removal of foreign body, the nasogastric feeding tube was inserted. About 10 days later, the nasogastric feeding tube was removed when they got healthy. Nine cases underwent cervical abscess incision and drainage under general anesthesia. The average postoperative hospital day was 11 days. Conclusion: The rigid esophagoscopy is a safe and effective method for the esophageal foreign bodies. And neck abscess incision must be necessary,when they suffered from esophageal perforation with neck abscess and other serious complications.

[The diagnosis and treatment of neck abscess and mediastinal abscess following esophageal perforation induced by esophageal foreign body]

Objective:The aim of this study is to discuss the clinical presentation, imaging examination and treatment of neck abscess and mediastinal abscess following esophageal perforation induced by esophageal foreign body. Method:Six patients all underwent lateral neck incision and drainage of neck abscess. Simultaneously, mediastinal abscess drainage was performed in 3 cases with mediastinal abscess. Result:All 6 patients were cured. The median time of extraction of gastric tube was 11 days (7-30 days). All patients were not treated with tracheotomy. Conclusion:Neck and chest CT should be done as soon as possible for suspected patients to definite the location of foreign body and the relationship between foreign body and surrounding structures. Patient who were suspected with neck abscess and mediastinal abscess should undergo surgery to remove foreign body and drain the infectious deep neck and mediastinal spaces as early as possible.

[Nasal glioma in sphenoid sinus: a case report and literature review]

Nasal glioma is a rare congenital malformation in maxillofacial region. It is sluggish, benign, non-tumorous and with low recurrence rate. It is important to evaluate whether there is any intracranial connection before the operation through CT or MRI to avoid the serious intracranial complications. We reported a case of a adult with a nasal glioma in sphenoid sinus, and discuss clinical characteristics, diagnosis, and pathology.

[Comparative study of cone-beam CT and spiral CT in measuring the length of styloid process]

Objective: To compare the difference of measuring the length of styloid process between spiral CT with high resolution and cone-beam CT(CBCT). Methods: Five specimens (including 5 pairs of styloid processes) were selected randomly from the Anatomy Laboratory of Otolaryngology Department, all the specimens underwent spiral CT with high resolution and cone-beam CT retrospectively.With the original DICOM data, the styloid processes were shown in one plate by multiple plate reconstruction technique, and later the length of styloid processes of each specimen were measured separately by software NNT Viewer (to CBCT) or Osrix (to spiral CT with high resolution). Results: The length of styloid processes measured by CBCT and spiral CT was (26.8±5.5) mm and (27.1±5.4) mm respectively, and there was no statistical difference between the two groups. Conclusion: In respect of measuring the length of styloid process, the CBCT has the same value in clinical practice comparing to spiral CT with high resolution.

[Retroperitoneal laparoscopic with renal pedicle rotation for partial nephrectomy of ventro-renal tumor]

OBJECTIVE

Retro-laparoscopic partial nephrectomy is a challenge for ventro-renal tumors, especially hilar tumors. The tumors are partial or entirely out of operative field and there is blind space for operation. To solve this problem, a set of techniques including renal pedicle rotation is developed.

METHODS

A set of techniques including renal pedicle rotation, double-layer suture, early artery unclamping for retro-laparoscopic nephrectomy for ventro-renal tumors, especially hilar tumors were developed. Hilar tumors were located anteriorly to the angle of the renal and renal arteries and in contact with the anterior surface of the renal artery. The evaluation of the outcomes included the operation time, warm ischemia time, estimated haemorrhage, surgical margin, renal function after operation, and complications. This study reviewed the data of 28 patients with ventro-renal tumor, including 15 patients with complex hilar tumors.

RESULTS

The average tumor size was (3.8±0.5) cm. The average R.E.N.A.L score was 8 (ranging from 7 to 9). The average warm ischemia time was (23.8±4.7) min, and suture time was (26.2±6.5) min, and operation time was (124.1±12.1) min. The median hospital stay was 4 days and the average estimated haemorrhage was (139.1±54.0) mL. All the surgeries were operated under laparoscope and no surgery switched to open surgery. Seven patients developed Clavien Dindo I-II complications after operation. Three patients (10.7%) developed collective system damage and received repair of collective system in time and three patients (10.7%) developed slightly gross hematuria (Clavien-Dindo I). Two patients developed wound infection (Clavien-Dind II). Three patients (10.7%) got renal vein clamped because of capillary hemorrhage from basilar part of tumors. There were 14 patients received early unclamping of renal artery, and no obvious renal vessel damage was found. There were statistically significant differences between the serum creatinine levels (P<0.05) and the estimated glomerular filtration rates (P=0.02) before and after surgery. All the patients' serum creatinine levels were in normal range and no patient needed regular dialysis. There was no positive surgical margin and the median follow-up was 7 months without local recurrence or distant metastasis.

CONCLUSION

It is safe and effective to apply renal pedicle rotation technique in retro-laparoscopic partial nephrectomy for ventro-renal tumors. The short-term follow-up results are optimistic, but long follow-up is required.

[Laryngeal undifferentiated soft-tissue sarcoma: a case report and review of literature]

Patient presented as a 74-year-old male complaining of hoarseness. Electronic laryngoscope showed a neoplasm whose size was about 1.0 cm×0.5 cm×0.5 cm at anterior commissure. A surgery was conducted to excise the neoplasm en bloc. The histopathological and immunohistochemistry examination suggested inflammatory myofibroblastic tumor. A month later, the patient presented with dyspnea and blood-stained sputum. CT scan of neck showed an occupation lesions under glottis. A tracheotomy and a CO₂ laser surgery was conducted due to patient's will. The histopathological and immunohistochemistry examination suggested undifferentiated sarcoma. We advised him keeping a tracheal cannula to receive further treatment such as radiotherapy or chemotherapy in oncology department, but the patient was not compliant with care instructions for personal reason. He was readmitted 2 months later for dyspnea after plugging the tube. Electronic laryngoscope showed a large neoplasm occupied the laryngeal vestibule, covering the glottis. CT and MRI scan showed the lesion involved spaces of supraglottic, glottic, subglottic and soft tissue around larynx. Hence, a total laryngotomy and bilateral functional neck dissection was conducted. The histopathological examination agreed with the former one. Three weeks later, the skin around his tracheal cannula swelled,ulcerated and pyorrheal. After 10 days of dressing change, patient died of uncontrolled infection.

[Risk factors of central neck lymph node metastasis in cN0 papillary thyroid carcinoma]

Objective:To investigate the risk factors of central neck lymph node metastasis (CNLNM) in cN0 papillary thyroid carcinoma. Method:Retrospective analysis of 114 patients with papillary thyroid carcinoma in stage of cN0 who underwent primary treatment. Collected the clinical and pathological data, used the univariate and multivariate analysis to investigate the risk factors of central neck lymph node metastasis and high volume central neck lymph node metastasis.Result:In the univariate analysis, age (48.2% in<45 years vs 27.6% in≥45 years), multifocal (51% with vs 27.7% without), nodular goiter (58.8% with vs 28.7% without), showed significant difference in prevalence of CNLNM. Age (14.3% in<45 years vs 1.7% in≥45 years), tumor size (19.2% >1 cm vs 4.5%≤1 cm) showed significant difference in prevalence of high volume CNLNM. Inmultivariate analysis, age (RR= 0.304), multifocal (RR= 3.637) and nodular goiter (RR= 4.132) showed the independent risk factor of CNLNM.Conclusion:For cN0 patients with thyroid papillary carcinoma, if the age is younger than 45 years old, the tumor is multifocal, or associatedwith nodular goiter, the surgery should be more aggressive in the prophylactic central neck dissection.

An assessment of the correlation between early postinfarction pyramidal tract Wallerian degeneration and nerve function recovery using diffusion tensor imaging

This study aimed to evaluate the clinical significance of diffusion tensor imaging (DTI) in the early diagnosis of pyramidal tract Wallerian degeneration (WD) and assessment of neurological recovery following cerebral infarction. This study included 23 patients with acute cerebral infarction and 10 healthy adult controls. All participants underwent both magnetic resonance imaging (MRI) and DTI scans. DTI images were analyzed using the Functional MRI of the Brain Software Library to determine the regions of interest (ROI) and obtain the mean diffusivity (MD) and fractional anisotropy (FA) value for each ROI. The correlation between FA or MD and postinfarction functional recovery of the nervous system was further analyzed to assess the feasibility of using a DTI scan in the evaluation of functional recovery of the nervous system in patients with cerebral infarction. DTI may be useful in detecting signals of early postinfarction pyramidal tract WD and is useful for the evaluation of postinfarction neurological recovery. Cerebral lesions were detected using MRI in all patients. It was found that in some patients, the FA value of the ipsilateral pyramidal tract on DTI was decreased as early as day 3 after the onset of infarction and in all patients by day 7. Subsequent correlation studies showed that the FA value of the ipsilateral pyramidal tract on day 13 was negatively correlated with the National Institutes of Health Stroke Scale score, but positively correlated with the Barthel Index, motricity index, and modified Rankin Scale scores.

[Primary neuroendocrine carcinoma of the tonsil: two case reports and review of the literature]

Neuroendocrine carcinoma(NEC) of the tonsil is extremely rare. Only a few cases of this tumor have been reported so far. In this article, we described two patients presented with abnormal sensation of throat or throat pain. The pathological examination were NEC. With review of the literatures, the clinical characteristics were summarized and therapeutic strategies were discussed.

[New advancement in diagnosis and treatment of head and neck lymphoma]

Malignant lymphomas are common malignant neoplastic of lymphatic hematopoietic system, and there are different clinic manifestation in different sites. Malignant lymphomas in the head and neck have characteristics in clinic features,pathologic types and the most common locations. This review is about the role of different clinic manifestation, pathologic types and the International Prognostic Idex(IPI)in the evaluation of prognosis in the head and neck lymphoma.

[Papillary thyroid microcarcinoma with huge lymph node metastasis and squamous cell cancerization:a case report]

We report a 75 years old woman with papillary thyroid microcarcinoma,and squamous cell cancer was found in her lymph node metastases.The patient was characterized by a cervical mass,which was diagnosed as papillary thyroid microcarcinoma by fine needle aspiration.Total thyroidectomy+right radical neck dissection+Ⅵ bilateral neck lymph node dissection were performed for the patient.

Evaluation of insertion-deletion markers suitable for genetic diversity studies and marker-trait correlation analyses in cultivated peanut (Arachis hypogaea L.)

Peanut is one of the most important oil crops worldwide. We used insertion-deletion (InDel) markers to assess the genetic diversity and population structure in cultivated peanut. Fifty-four accessions from North China were genotyped using 48 InDel markers. The markers amplified 61 polymorphic loci with 1 to 8 alleles and an average of 2.6 alleles per marker. The polymorphism information content values ranged from 0.0364 to 0.9030, with an average of 0.5038. Population structure and neighbor-joining (NJ) tree analyses suggested that all accessions could be divided into four clusters (A1-A4), using the NJ method. Likewise, four subpopulations (G1-G4) were identified using STRUCTURE analysis. A principal component analysis was also used and results concordant with the other analysis methods were found. A multi-linear stepwise regression analysis revealed that 13 InDel markers correlated with five measured agronomical traits. Our results will provide important information for future peanut molecular breeding and genetic research.

Formation of pH-responsive drug-delivery systems by electrospinning of vesicle-templated nanocapsule solutions

A novel nanofibrous membrane, which contains chitosan/sodium alginate nanocapsules constructed by vesicle systems, has been fabricated via an electrospinning process as a drug-delivery system.

Giant room temperature elastocaloric effect of PbTiO3 ferroelectric materials with 90° domain structure

The elastocaloric effect in PbTiO₃ with 90° domain structure under the applied stress field at room temperature has been studied. A negative ΔTσ of −7.2 K can be obtained by controlled polarization switching under the applied stress fields.

Effect of melatonin on oncosis of myocardial cells in the myocardial ischemia/reperfusion injury rat and the role of the mitochondrial permeability transition pore

We aimed to evaluate the effect of melatonin on myo-cardial cell oncosis in the myocardial ischemia/reperfusion injury rat, and the role of the mitochondrial permeability transition pore (MPTP) therein. Sprague Dawley rats (N = 60) were randomly divided into five groups of 12 rats each: control, ischemia/reperfusion (I/R), melatonin treatment (MT), melatonin treatment + atractyloside (MT+ATR), and atractyloside (ATR). We prepared the myocardial ischemia/reperfusion model by reperfusion after the left anterior descending coronary artery was ligated for 30 min. The MT rats were given a 10 mg/kg MT intra-venous injection immediately thereafter; the MT+ATR rats were also given a 5 mg/kg ATR intravenous injection 15 min before the ischemia; the ATR rats were given the ATR injection only. After 2-h re-perfusion, myocardial tissue was extracted, the infarction size was determined, and myocardial ultrastructures were observed using electron microscopy. The expression level of the preoncosis receptor (porimin), which can induce membrane injury, was determined by western blot; the nicotinamide adenine dinucleotide (NAD(+)) content was determined spectrophotometrically. The four treatment groups showed upregulat-ed expression of myocardial porimin, increased myocardial infarction size, and reduced NAD(+) content (P < 0.05). Compared with the I/R and MT+ATR groups, MT rats showed downregulated expression of myo-cardial porimin, reduced myocardial infarct size, and increased myo-cardial cell NAD(+) content (P < 0.05). The above indices between the ATR and MT+ATR groups were not significantly different (P > 0.05). Thus, MT might protect myocardial ischemia/reperfusion rats by inhibiting MPTP opening and reducing myocardial cell oncosis.

Effects and toxicity of neoadjuvant chemotherapy preoperative followed by adjuvant chemoradiation in small cell neurdendocrine cervical carcinoma

OBJECTIVE

To determine the efficacy and toxicity of a combined-modality regimen of neoadjuvant chemotherapy (NACT) before primary radical surgery followed by adjuvant chemoradiation in small cell neuroendocrine cervical cancer (SCNEC) patients.

MATERIALS AND METHODS

The study was approved by the ethics committee of the present hospital. The records of 23 SCNEC patients who received NACT before primary radical surgery were reviewed at the Zhejiang Cancer Hospital between January 1998 and May 2010. All patients received one to four cycles of NACT and two to eight cycles of chemotherapy (NACT and adjuvant chemotherapy) on the basis of platinum, 17 (73.9%) patients received NACT using a regimen consisting of etoposide and cisplatin (EP). Eighteen (85.7%) patients received adjuvant chemotherapy using a regimen consisting of PE and EP. Kaplan-Meier and Cox regression methods were used for analyses.

RESULTS

Of the 23 eligible patients, 18 had Stages I-IIA, five had Stages IIB-IIIB disease. Twelve patients (52.2%) developed grade 3 and 4 neutropenia. Fourteen patients (60.9%) developed grade 3 and 4 anemia. The majority of grade 3 and 4 neutropenia and non-hematologic toxicities were usually self-limited. Three patients (13.0%) who postoperative pathology showed pathologic complete response (CR) had better prognosis than those did not show pathologic CR; the median survival was 69.5 months (range, 51.1-177.1), 54.5 months (range: 7.3-81.5), respectively. In univariate analysis, lymphovascular space invasion (LSI) (p = 0.013), and deep stromal invasion (DSI) (p = 0.001) were considered poor prognostic factors. With a median follow-up for surviving patients was 40.8 months (range, 7-177), 12 patients recurred, 11 of which had died. The estimated three- and five-year overall survival (OS) rates for all patients were 55.8% and 39.9%, respectively.

CONCLUSION

NACT before primary radical surgery followed by adjuvant chemoradiation or chemotherapy was well tolerated and seems to be effective for early stage SCNEC patients. Prospective clinical study is necessary and we hope that this research's results help to design a prospective clinical study.

First Report of Neocosmospora striata Causing Peanut Pod Rot in China

In 2008, an outbreak of pod rot of peanut (Arachis hypogaea L.) occurred on most of the peanut cultivars in the Old Yellow River drainage area, the largest peanut-growing region in China. Disease incidence reached as high as 90% in some fields, causing severe yield losses. The black rot of pods and blackened, nonrotting taproots is similar to symptoms of peanut black rot caused by Cylindrocladium parasiticum, but the reddish orange perithecia of C. parasiticum were not found on the taproots close to the surface of the soil. The foliage of affected plants was generally asymptomatic, but some plants turned greener. This pod rot disease was further investigated in 2008 and 2010. Twenty-three Fusarium-like isolates were obtained from symptomatic, surface-disinfested pods with a frequency of 82%. These isolates were fast growing, with flat, thin, and grayish white colonies when cultured on potato dextrose agar (PDA) at 28°C for 3 to 4 days. The hyaline, elongated to cylindrical conidia, aggregated in slimy heads on conidiogenous cells developed from undifferentiated hyphae when observed with the light microscope. The size of conidia (single celled or one septum) varied from 3 to 9 μm long and 1.5 to 3.5 μm wide on the basis of the measurement of 50 spores. Some conidia appeared slightly curved. Ascomata formed within 10 to 14 days, with a punctate appearance on the colony. The cerebriform ascomata were dark brown, pyriform, ostiolate, glabrous, 120 to 170 × 90 to 130 μm, and with necks 30 to 50 μm long. Asci measured 60 to 90 × 6 to 10 μm, were cylindrical to cylindric-clavate, thin walled, and had an apical ring. Ascospore arrangement was obliquely uniseriate or partially biseriate, very pale yellow to hyaline, ellipsoidal, and measured 8 to 12 × 4.5 to 6 μm. Some spores had a median transverse straight or curved septum and were slightly constricted at the septum, with 6 to 10 thin, transverse, hyaline flanges. Morphological characteristics of the isolates with ascomata dark brown and ascospores with 6 to 10 transverse hyaline flanges matched the description for Neocosmospora striata (1). The internal transcribed spacer (ITS) region of rDNA was amplified from extracted template DNA with primer pairs ITS4/ITS5 and sequenced. A 591-bp amplicon (GenBank Accession No. HM461900) had 99% sequence identity with Fusarium solani (HQ607968 and HQ608009) and N. vasinfecta (GU213063), which indicated that these fungi belong to the genus Neocosmospora or Fusarium, although there is no direct sequence evidence that they are N. striata. N. striata has only been previously reported in Japan (2). This species is unique because of the dark brown ascomata and there is no comparable species (1). Koch's postulates were completed by surface-disinfesting 80 peanut pods of cv. Jihua 9813 and soaking them in conidial suspensions (10⁵ conidia/ml) for 2 min. Another 80 other pods soaked in sterile water served as controls. All peanuts were incubated in moist petri dishes under darkness at 28°C. Symptoms similar to those originally observed in the field formed within 10 days on all inoculated peanut pods and not the controls. N. striata was reisolated from all affected peanut pods. To our knowledge, this is first report of N. striata causing peanut pod rot in China and the first description of the anamorph of the fungus. References: (1) P. F. Cannon et al. Trans. Br. Mycol. Soc. 82:673, 1984. (2) S. Udagawa et al. Trans. Mycol. Soc. Jpn. 16:340, 1975.

Metal-assisted electrochemical etching of silicon

In this paper the metal-assisted electrochemical etching of silicon is introduced. By electrochemical measurement and sequent simulation, it is revealed that the potential of the valence band maximum at the silicon/metal interface is more negative than that of the silicon/electrolyte interface. Accordingly, holes injected from the back contact are driven preferentially to the silicon/metal interface. Consequently, silicon below metal is electrochemically etched much faster than a naked silicon surface without metal coverage. Metals such as Ag and Cu have been utilized to catalyze the electrochemical etching. Feature sizes as small as 30 nm can be achieved by metal-assisted electrochemical etching. Meanwhile, the metal-assisted electrochemical etching method enables convenient control over the etching direction of non-(100) substrates, and facilitates the fabrication of orientation-modulated silicon nanostructures.

Vortex polarization states in nanoscale ferroelectric arrays

Two-dimensional arrays of ferroelectric lead zirconate titanate (PZT) nanodots were fabricated using pulsed laser deposition through ultrathin anodic aluminum oxide membrane stencil masks. The static distribution of polarization configurations was investigated using in- and out-of-plane piezoresponse force microscopy (PFM). The observed presence of an in-plane polarization component in nominally (001) oriented PZT suggests the existence of a significant deviation from the regular tetragonal structure that allows the formation of complex core-polarization states. Core-polarization states may indicate the presence of quasi-toroidal polarization ordering. The experimental results are compared with a theoretical model to determine the fingerprint of a vortex polarization state in PFM.

Periodic ZnO nanorod arrays defined by polystyrene microsphere self-assembled monolayers

We demonstrate a low-cost and effective method to fabricate hexagonally patterned, vertically aligned ZnO nanorod arrays. Selective wet-etching is used to develop the catalyzing gold particle hexagonal pattern with the aid of a polystyrene microsphere self-assembled monolayer. The gold particles have tunable sizes independent of the polystyrene microsphere's diameter and are inherently round in shape. Each ZnO rod is grown individually from a catalyzing site via catalyst-initiated epitaxy, and the original hexagonal periodicity is well-preserved. The rods have flat ends, and the diameters of the rods can be controlled well by the amount of source materials. This method provides a promising way to create ZnO one-dimensional nanostructures for applications as two-dimensional photonic crystal, sensor arrays, nanolaser arrays, and optoelectronic devices.

26 S proteasome-mediated degradation of topoisomerase II cleavable complexes

DNA topoisomerase II (TOP2) cleavable complexes represent an unusual type of DNA damage characterized by reversible TOP2-DNA cross-links and DNA double strand breaks. Many antitumor drugs and physiological stresses are known to induce TOP2 cleavable complexes leading to apoptotic cell death and genomic instability. However, the molecular mechanism(s) for repair of TOP2 cleavable complexes remains unclear. In the current studies, we show that TOP2 cleavable complexes induced by the prototypic TOP2 poison VM-26 are proteolytically degraded by the ubiquitin/26 S proteasome pathway. Surprisingly the TOP2beta isozyme is preferentially degraded over TOP2alpha isozyme. In addition, transcription inhibitors such as 5,6-dichlorobenzimidazole riboside and camptothecin can substantially block VM-26-induced TOP2beta degradation. These results are consistent with a model in which the repair of TOP2beta cleavable complexes may involve transcription-dependent proteolysis of TOP2beta to reveal the protein-concealed double strand breaks.

Nucleolytic cleavage of the mixed lineage leukemia breakpoint cluster region during apoptosis

VP-16 (etoposide) has recently been shown to induce topoisomerase II (TOP2)-mediated DNA cleavage within the mixed lineage leukemia (MLL) breakpoint cluster region (bcr), suggesting a role of TOP2 in MLL gene rearrangement. In our current studies, we have compared the induction of DNA cleavage within the MLL bcr in different cell lines after treatment with various anticancer drugs. All anticancer drugs tested including VP-16 (a TOP2-directed drug), camptothecin (a topoisomerase I-directed drug), 5-fluorouracil and methotrexate (antimetabolites), and vinblastine (a microtubule inhibitor) induced the same site-specific cleavage within the MLL bcr. This cleavage was shown to be nuclease-mediated but not TOP2-mediated by the following observations: 1) drug-induced cleavage within the MLL bcr was not protein-linked; 2) unlike TOP2-mediated cleavage, drug-induced DNA cleavage within the MLL bcr was kinetically slow and coincided with the formation of the apoptotic nucleosomal DNA ladder; 3) drug-induced cleavage within the MLL bcr was unaffected in cells with reduced nuclear TOP2; and 4) drug-induced cleavage within the MLL bcr was abolished by the caspase inhibitor, Z-Asp(OCH(3))-Glu(OCH(3))-Val-Asp(OCH(3))-FMK. The possibility that an apoptotic nuclease may be involved in cleavage of the MLL bcr and MLL gene translocation is discussed.

Ubiquitin/26S proteasome-mediated degradation of topoisomerase I as a resistance mechanism to camptothecin in tumor cells

Camptothecin (CPT) induces down-regulation of topoisomerase I (TOP1) via an ubiquitin/26S proteasome pathway. Studies using a panel of breast and colorectal cancer cell lines as well as primary nontransformed and oncogene-transformed cells have demonstrated that CPT-induced down-regulation exhibits a high degree of heterogeneity. In general, nontransformed cells are much more proficient in CPT-induced TOP1 down-regulation than their transformed counterparts. Among the breast and colorectal cancer cell lines, there was a general correlation between the extent of CPT-induced TOP1 down-regulation and CPT resistance. The breast cancer cell line ZR-75-1, the most sensitive to CPT, was completely defective in CPT-induced TOP1 down-regulation, whereas the breast cancer cell line BT474, the least sensitive to CPT, exhibited effective CPT-induced TOP1 down-regulation. The 26S proteasome inhibitor MG132 was shown to inhibit CPT-induced down-regulation of TOP1 in BT474 cells and selectively sensitized BT474 but not ZR-75-1 cells to CPT-induced cytotoxicity and apoptosis. In the aggregate, these results suggest that CPT-induced down-regulation of TOP1 could be an important parameter for determining CPT sensitivity/resistance in tumor cells. Analysis of the levels of TOP1 cleavable complexes, SUMO-1-TOP1 conjugates, and ubiquitin-TOP1 conjugates in ZR-75-1 and BT474 cells has suggested that the heterogeneity of CPT-induced down-regulation of TOP1 in tumor cells is at least in part attributable to altered regulation of a process(es) downstream from the TOP1 cleavable complex.

Factors associated with nursing home entry for older people in Taiwan, Republic of China

Taiwan is facing a rapid change in the composition of its population. As the population ages, a greater demand for long-term care services and, in particular, nursing homes is expected. Before deciding who really needs nursing home care, it is important for policy makers to understand the current pattern of utilisation and what factors are associated with entry. This research assesses the relative importance of predisposing, enabling and need factors that lie behind this. It is based on a survey of elderly people in registered nursing homes, a comparison with a national sample of elderly people in their own homes and interviews with the lucid elderly patients (i.e. could communicate with no problems) and their carers. It was found that nursing home entry was associated with advanced age, gender, educational level and dependency levels of elderly people. After controlling for age, need factors have the greatest impact on admission. Specific medical problems such as cardiovascular, neurological and skeletal muscular diseases were also major contributors. Although most elderly people in Taiwan are cared for in their own homes by their families, under certain circumstances entry to a nursing home seemed inevitable. Decisions about nursing home entry were mainly taken within a family context with adult children being the main players while professionals played a relatively minimal role.

Tumor cell death induced by topoisomerase-targeting drugs

DNA topoisomerases are double-edged swords. They are essential for many vital functions of DNA during normal cell growth. However, they are also highly vulnerable under various physiological and nonphysiological stresses because of their delicate act on breaking and rejoining DNA. These stresses (e.g. exposure to topoisomerase poisons, acidic pH, and oxidative stresses) can convert DNA topoisomerases into DNA-breaking nucleases, resulting in cell death and/or genomic instability. The importance of topoisomerase-mediated DNA cleavage in tumor cell death and carcinogenesis has been recognized. This review focuses on recent findings concerning the molecular mechanisms of the stress responses to topoisomerase-mediated DNA damage. The involvement of ubiquitin/26S proteasome and SUMO/UBC9 in these processes, as well as the role of topoisomerase cleavable complexes in apoptotic cell death are discussed.

Giant cell reparative granuloma of the temporal bone

Giant cell reparative granuloma (GCRG) is an uncommon non-neoplastic lesion that typically occurs in the mandible and maxilla: however, its involvement with the temporal bone is rare. It is usually misdiagnosed as a giant cell tumor. Although regarded as a benign process, GCRG may be locally aggressive. In this paper, we describe two cases of GCRG of the temporal bone and review the pertinent literature published in English. The clinical course, histological evaluation, diagnosis, differential diagnosis, treatment and prognosis of GCRG of the temporal bone were investigated.

[Evaluation of the effects of hospital nurse retention programs in Taiwan]

The purpose of the study was to examine the effectiveness of current nursing retention programs in hospitals in Taiwan and the relationships between job satisfaction and intention to stay. A proportional multi-stratified random sampling technique was used to recruit nurses who were working in accredited district and regional hospitals in the years 1996 to 1998. Data were collected through a structured questionnaire from 471 nurses with 2 years of nursing experience, and analyzed by non-parametric and logistic regression. The results showed that a majority of the respondents positively recognized the importance of the DOH retention policy and were satisfied with its implementation. Nurses whose working hospital had a retention program had higher job satisfaction and intention to stay than those without a retention program. Based on the findings, nursing and hospital administrators could develop retrievable data gathered during an ongoing organizational retention policy and develop strategic planning for stabilizing their clinical nursing workforce.

Atp-bound topoisomerase ii as a target for antitumor drugs

Topoisomerase II (TOP2) poisons interfere with the breakage/reunion reaction of TOP2 resulting in DNA cleavage. In the current studies, we show that two different classes (ATP-sensitive and -insensitive) of TOP2 poisons can be identified based on their differential sensitivity to the ATP-bound conformation of TOP2. First, in the presence of 1 mm ATP or the nonhydrolyzable analog adenosine 5'-(beta,gamma-imino)triphosphate, TOP2-mediated DNA cleavage induced by ATP-sensitive TOP2 poisons (e.g. doxorubicin, etoposide, mitoxantrone, and 4'-(9-acridinylamino)methanesulfon-m-anisidide) was 30-100-fold stimulated, whereas DNA cleavage induced by ATP-insensitive TOP2 poisons (e.g. amonafide, batracylin, and menadione) was only slightly (less than 3-fold) affected. In addition, ADP was shown to strongly antagonize TOP2-mediated DNA cleavage induced by ATP-sensitive but not ATP-insensitive TOP2 poisons. Second, C427A mutant human TOP2alpha, which exhibits reduced ATPase activity, was shown to exhibit cross-resistance to all ATP-sensitive but not ATP-insensitive TOP2 poisons. Third, using ciprofloxacin competition assay, TOP2-mediated DNA cleavage induced by ATP-sensitive but not ATP-insensitive poisons was shown to be antagonized by ciprofloxacin. These results suggest that ATP-bound TOP2 may be the specific target of ATP-sensitive TOP2 poisons. Using Lac repressor-operator complexes as roadblocks, we show that ATP-bound TOP2 acts as a circular clamp capable of entering DNA ends and sliding on unobstructed duplex DNA.

Stimulation of topoisomerase II-mediated DNA damage via a mechanism involving protein thiolation

The breakage/reunion reaction of DNA topoisomerase II (TOP2) can be interrupted by DNA intercalators (e.g., doxorubicin), enzyme binders (e.g., etoposide), or DNA lesions (e.g., abasic sites) to produce TOP2-mediated DNA damage. Here, we demonstrate that thiol alkylation of TOP2 can also produce TOP2-mediated DNA damage. This conclusion is supported by the following observations using purified TOP2: (1) Thiol-reactive quinones were shown to induce TOP2-mediated DNA cleavage. (2) Thiol-reactive compounds such as N-ethylmaleimide (NEM), disulfiram, and organic disulfides [e.g., 2,2'-dithiobis(5-nitropyridine)] were also shown to induce TOP2-mediated DNA cleavage with similar reaction characteristics as thiol-reactive quinones. (3) TOP2-mediated DNA cleavage induced by thiol-reactive quinones was completely abolished using mutant yeast TOP2 with all cysteine residues replaced with alanine (cysteineless TOP2). These results suggest the possibility that cellular DNA damage could occur indirectly through thiolation of a nuclear protein, TOP2. The implications of this reaction in carcinogenesis and apoptotic cell death are discussed.

Mechanism of action of camptothecin

Camptothecin (CPT) class of compounds has been demonstrated to be effective against a broad spectrum of tumors. Their molecular target has been firmly established to be human DNA topoisomerase I (topo I). CPT inhibits topo I by blocking the rejoining step of the cleavage/religation reaction of topo-I, resulting in accumulation of a covalent reaction intermediate, the cleavable complex. The primary mechanism of cell killing by CPT is S-phase-specific killing through potentially lethal collisions between advancing replication forks and topo-I cleavable complexes. Collisions with the transcription machinery have also been shown to trigger the formation of long-lived covalent topo-I DNA complexes, which contribute to CPT cytotoxicity. Two novel repair responses to topo-I-mediated DNA damage involving covalent modifications of topo-I have been discovered. The first involves activation of the ubiquitin/26S proteasome pathway, leading to degradation of topo-I (CPT-induced topo-I downregulation). The second involves SUMO conjugation to topo-I. The potentials roles of these new mechanisms for repair of topo-I-mediated DNA damage in determining CPT sensitivity/resistance in tumor cells are discussed.

Anticancer activity evaluation of the solanum glycoalkaloid solamargine. Triggering apoptosis in human hepatoma cells

Solamargine, an herbal and molluscicidal medicine derived from Solanum incanum, is a steroidal alkaloid glycoside. To characterize the anticancer mechanism of solamargine on human hepatoma cells (Hep3B), changes of cell morphology, DNA content, and gene expression of cells after solamargine treatment were studied. The appearance in solamargine-treated cells of chromatin condensation, DNA fragmentation, and a sub-G(1) peak in a DNA histogram suggests that solamargine induces cell death by apoptosis. The maximum number of dead Hep3B cells was detected within 2 hr of incubation with constant concentrations of solamargine, and no further cell death was observed after an extended incubation with solamargine, indicating that the action of solamargine was irreversible. To determine the susceptibility of cell phases to solamargine-mediated apoptosis, Hep3B cells were synchronized at defined cell cycles by cyclosporin A, colchicine, and genistein, followed by solamargine treatment. The IC(50) values of solamargine for control, G(0)/G(1)-, M-, and G(2)/M-synchronized Hep3B cells were 5.0, > 10, 3.7, and 3.1 microg/mL, implying that cells in the G(2)/M phases are relatively susceptible to solamargine-mediated apoptosis. In addition, a parallel up-regulation of tumor necrosis factor receptor (TNFR)-I and -II on Hep3B cells was detected after solamargine treatment, and the solamargine-mediated cytotoxicity could be neutralized with either TNFR-I or -II specific antibody. Therefore, these results reveal that the actions of TNFR-I and -II on Hep3B cells may be independent, and both are involved in the mechanism of solamargine-mediated apoptosis.

Topoisomerase I inhibition and cytotoxicity of 5-bromo- and 5-phenylterbenzimidazoles

Topoisomerase I is an enzyme that is essential for maintaining the three-dimensional structure of DNA during the processes of transcription, translation and mitosis. With the introduction of new clinical agents that are effective in poisoning topoisomerase I, this enzyme has proved to be an attractive molecular target in the development of anticancer drugs. Several terbenzimidazoles have been identified as potent topoisomerase I poisons. Structure-activity data on various terbenzimidazoles have revealed that the presence of lipophilic substituents at the 5-position of various terbenzimidazoles correlates with enhanced cytotoxicity. While the effect of having substituents at both the 5- and 6-positions had not been evaluated, previous studies did indicate that the presence of a fused benzo-ring at the 5,6-position results in a significant decrease in topoisomerase I poisoning activity and cytotoxicity. In the present study we investigated whether substituents at both the 5- and 6-positions of varied terbenzimidazoles would allow for retention of topo I poisoning activity. The 6-bromo, 6-methoxy, or 6-phenyl derivatives of both 5-bromo- and 5-phenylterbenzimidazole were synthesized and evaluated for topo I poisoning activity, as well as their cytotoxicity toward human lymphoblastoma cells. The data indicate that such derivatives do retain similar topo I poisoning activity and possess cytotoxicity equivalent to either 5-bromo- or 5-phenylterbenzimidazole. Significant enhancement in the topoisomerase I poisoning activity and cytotoxicity of 5-phenylterbenzimidazole is observed when the 2"-position is substituted with either a chloro or trifluoromethyl substituent. The influence of such substituents on the biological activity of 5.6-dibromoterbenzimidazole (6a) was also explored. In the case of either 2"-chloro-5,6-dibromoterbenzimidazole (6b) or 2"-trifluoromethyl-5,6-dibromoterbenzimidazole (6c), topoisomerase I poisoning was not enhanced relative to 6a. While cytotoxicity toward RPMI 8402 was also not significantly affected, comparative studies performed against several solid human tumor cell lines did reveal a significant increase in cytotoxicity observed for 6c as compared to 6a.

SUMO-1 conjugation to human DNA topoisomerase II isozymes

Topoisomerase I-mediated DNA damage induced by camptothecin has been shown to induce rapid small ubiquitin-related modifier (SUMO)-1 conjugation to topoisomerase I. In the current study, we show that topoisomerase II-mediated DNA damage induced by teniposide (VM-26) results in the formation of high molecular weight conjugates of both topoisomerase IIalpha and IIbeta isozymes in HeLa cells. Immunological characterization of these conjugates suggests that both topoisomerase IIalpha and IIbeta isozymes are conjugated to SUMO-1. The involvement of SUMO-1/UBC9 in the modification of topoisomerase II isozymes is also supported by the demonstration of physical interaction between topoisomerase II and SUMO-1/UBC9. Surprisingly, ICRF-193, which does not induce topoisomerase II-mediated DNA damage but traps topoisomerase II into a circular clamp conformation, is also shown to induce similar SUMO-1 conjugation to topoisomerase II isozymes. In addition, we show that both oxidative and heat shock stresses, which can cause protein damage, rapidly increase nuclear SUMO-1 conjugates. These studies raise the question on whether SUMO-1 conjugation to topoisomerases is an indirect result of a DNA damage response or a direct result because of protein conformational changes.

Site-specific topoisomerase I-mediated DNA cleavage induced by nogalamycin: a potential role of ligand-induced DNA bending at a distal site

Many DNA binding ligands (e.g., nogalamycin, actinomycin D, terbenzimidazoles, indolocarbazoles, nitidine, and coralyne) and various types of DNA lesions (e.g., UV dimers, DNA mismatches, and abasic sites) are known to stimulate topoisomerase I-mediated DNA cleavage. However, the mechanism(s) by which these covalent and noncovalent DNA interactions stimulate topoisomerase I-mediated DNA cleavage remains unclear. Using nogalamycin as a model, we have studied the mechanism of ligand-induced topoisomerase I-mediated DNA cleavage. We show by both mutational and DNA footprinting analyses that the binding of nogalamycin to an upstream site (from position -6 to -3) can induce highly specific topoisomerase I-mediated DNA cleavage. Substitution of this nogalamycin binding site with a DNA bending sequence (A(5)) stimulated topoisomerase I-mediated DNA at the same site in the absence of nogalamycin. Replacement of the A(5) sequence with a disrupted DNA bending sequence (A(2)TA(2)) significantly reduced the level of topoisomerase I-mediated DNA cleavage. These results, together with the known DNA bending property of nogalamycin, suggest that the nogalamycin-DNA complex may provide a DNA structural bend to stimulate topoisomerase I-mediated DNA cleavage.

Tyr115, gln165 and trp209 contribute to the 1, 2-epoxy-3-(p-nitrophenoxy)propane-conjugating activity of glutathione S-transferase cGSTM1-1

We investigated the epoxidase activity of a class mu glutathione S-transferase (cGSTM1-1), using 1,2-epoxy-3-(p-nitrophenoxy)propane (EPNP) as substrate. Trp209 on the C-terminal tail, Arg107 on the alpha4 helix, Asp161 and Gln165 on the alpha6 helix of cGSTM1-1 were selected for mutagenesis and kinetic studies. A hydrophobic side-chain at residue 209 is needed for the epoxidase activity of cGSTM1-1. Replacing Trp209 with histidine, isoleucine or proline resulted in a fivefold to 28-fold decrease in the k(cat)(app) of the enzyme, while a modest 25 % decrease in the k(cat)(app) was observed for the W209F mutant. The rGSTM1-1 enzyme has serine at the correponding position. The k(cat)(app) of the S209W mutant is 2. 5-fold higher than that of the wild-type rGSTM1-1. A charged residue is needed at position 107 of cGSTM1-1. The K(m)(app)(GSH) of the R107L mutant is 38-fold lower than that of the wild-type enzyme. On the contrary, the R107E mutant has a K(m)(app)(GSH) and a k(cat)(app) that are 11-fold and 35 % lower than those of the wild-type cGSTM1-1. The substitutions of Gln165 with Glu or Leu have minimal effect on the affinity of the mutants towards GSH or EPNP. However, a discernible reduction in k(cat)(app) was observed. Asp161 is involved in maintaining the structural integrity of the enzyme. The K(m)(app)(GSH) of the D161L mutant is 616-fold higher than that of the wild-type enzyme. In the hydrogen/deuterium exchange experiments, this mutant has the highest level of deuteration among all the proteins tested. We also elucidated the structure of cGSTM1-1 co-crystallized with the glutathionyl-conjugated 1, 2-epoxy-3-(p-nitrophenoxy)propane (EPNP) at 2.8 A resolution. The product found in the active site was 1-hydroxy-2-(S-glutathionyl)-3-(p-nitrophenoxy)propane, instead of the conventional 2-hydroxy isomer. The EPNP moiety orients towards Arg107 and Gln165 in dimer AB, and protrudes into a hydrophobic region formed by the loop connecting beta1 and alpha1 and part of the C-terminal tail in dimer CD. The phenoxyl ring forms strong ring stacking with the Trp209 side-chain in dimer CD. We hypothesize that these two conformations represent the EPNP moiety close to the initial and final stages of the reaction mechanism, respectively.