NRT1.1B mediates rice plant growth and soil microbial diversity under different nitrogen conditions

Interactions between microorganisms and plants can stimulate plant growth and promote nitrogen cycling. Nitrogen fertilizers are routinely used in agriculture to improve crop growth and yield; however, poor use efficiency impairs the optimal utilization of such fertilizers. Differences in the microbial diversity and plant growth of rice soil under different nitrogen application conditions and the expression of nitrogen-use efficiency-related genes have not been previously investigated. Therefore, this study investigates how nitrogen application and nitrogen-use efficiency-related gene NRT1.1B expression affect the soil microbial diversity and growth indices of two rice varieties, Huaidao 5 and Xinhuai 5. In total, 103,463 and 98,427 operational taxonomic units were detected in the soils of the Huaidao 5 and Xinhuai 5 rice varieties, respectively. The Shannon and Simpson indices initially increased and then decreased, whereas the Chao and abundance-based coverage estimator indices decreased after the application of nitrogen fertilizer. Nitrogen fertilization also reduced soil bacterial diversity and richness, as indicated by the reduced abundances of Azotobacter recorded in the soils of both rice varieties. Nitrogen application initially increased and then decreased the grain number per panicle, yield per plant, root, stem, and leaf nitrogen, total nitrogen content, glutamine synthetase, nitrate reductase, urease, and root activities of both varieties. Plant height showed positive linear trends in response to nitrogen application, whereas thousand-grain weights showed a negative trend. Our findings may be used to optimize nitrogen fertilizer use for rice cultivation and develop crop-variety-specific strategies for nitrogen fertilizer application.

High temperature stress induced oxidative stress, gut inflammation and disordered metabolome and microbiome in tsinling lenok trout

Tsinling lenok trout (Brachymystax lenok tsinlingensis Li) is a species of cold-water salmon that faces serious challenges due to global warming. High temperature stress has been found to damage the gut integrity of cold-water fish, impacting their growth and immunity. However, limited research exists on the causal relationship between gut microbial disturbance and metabolic dysfunction in cold-water fish induced by high temperature stress. To address this gap, we conducted a study to investigate the effects of high temperature stress (24 °C) on the gut tissue structure, antioxidant capacity, gut microorganisms, and metabolome reactions of tsinling lenok trout. Our analysis using 16 S rDNA gene sequencing revealed significant changes in the gut microbial composition and metabolic profile. Specifically, the abundance of Firmicutes and Gemmatimonadetes decreased significantly with increasing temperature, while the abundance of Bacteroidetes increased significantly. Metabolic analysis revealed a significant decrease in the abundance of glutathione, which is synthesized from glutamate and glycine, under high temperature stress. Additionally, there was a notable reduction in the levels of adenosine, inosine, xanthine, guanosine, and deoxyguanosine, which are essential for DNA/RNA synthesis. Conversely, there was a significant increase in the abundance of D-glucose 6 P. Furthermore, high temperature stress adversely affects intestinal structure and barrier function. Our findings provide valuable insights into the mechanism of high temperature stress in cold-water fish and serve as a foundation for future research aimed at mitigating the decline in production performance caused by such stress.

Outcomes of Consolidative Thoracic Radiation within First-Line Chemoimmunotherapy in Extensive-Stage Small-Cell Lung Cancer: Results from a Single Cancer Center

PURPOSE/OBJECTIVE(S)

Thoracic radiation (TRT) benefits local control undoubtedly and survival with some minor controversy in extensive-stage small-cell lung cancer (ES-SCLC) patients undergoing radiotherapy in the chemoradiotherapy era. However, whether TRT could further enhance the benefit of immune checkpoint inhibitors (ICIs) maintenance on outcomes in the immunotherapy era is still unclear. This study aims to investigate the role of consolidative TRT in ES-SCLC patients receiving first-line chemoimmunotherapy followed by immunotherapy maintenance.

MATERIALS/METHODS

Outcomes of patients who were treated with first-line chemo-immunotherapy followed by ICIs maintenance for ES-SCLC were reviewed. Based on TRT or not, patients were allocated to TRT group or non-TRT group. Progression-free survival (PFS), overall survival (OS) and local-recurrence free survival (LRFS) were calculated by the Kaplan-Meier method and compared by log-rank test.

RESULTS

A total of 100 patients with no progressive disease after 4 cycles of chemotherapy were retrospectively analyzed between January 2020 and December 2021 and were allocated into TRT group (n = 47) and non-TRT group (n = 53). The median follow-up time was 20.3 months. The median PFS and OS in TRT were 9.1 months and 21.8 months, versus 8.8 months (p = 0.93) and 24.3 months (p = 0.63), respectively, in non-TRT. ICIs agents consisted of Durvalumab (59.0%) and Atezolizumab (41.0%). The median dose of TRT is 50 Gy (IQR: 45 - 54), while the median interval time from chemotherapy completion to TRT was 31 days (IQR: 12 - 44.5). Only 10 (21.3%) patients terminated ICIs in the period of TRT. The rate of intrathoracic progression after the first-line therapy in TRT significantly decreased compared to that with non-TRT (20.0% versus 55.9%, p = 0.003). The median LRFS time in TRT was not reached, but significantly longer than 10.8 months in non-TRT (HR = 0.27, p < 0.01). Second-line chemotherapy significantly prolonged survival compared to that with chemo-free patients (mOS: 24.5 vs. 21.4 months, p = 0.026). The subgroup analysis showed a trend of patients with brain metastases benefit from TRT (21.8 versus 13.7 months, HR 0.61, p = 0.38) while liver metastases did not (13.3 versus 15.0 months, HR 1.80, p = 0.21). Of 47 patients with TRT, only 10.6% of patients experienced grade 3 radiation-induced pneumonitis, while no grade 4 or 5 adverse events occurred. None of patients experienced grade ≥ 3 treatment-related cardiac events.

CONCLUSION

Consolidative TRT in the period of immunotherapy maintenance followed first-line chemo-immunotherapy did not prolong OS and PFS but increased LRFS in ES-SCLC.

[Diagnosis and treatment of blunt high-grade pancreatic trauma]

The clinical data of 20 patients with blunt high-grade pancreatic trauma who were admitted to the Department of Hepatobiliary and Pancreatic Surgery of Changhai Hospital Affiliated to Naval Military Medical University from December 2003 to February 2022 were retrospectively analyzed. There were 15 males and 5 females with a median age of 39 years (range: 14-54 years). The degree of pancreatic injury was graded according to the American Association for the Surgery of Trauma (AAST) scale, including 10 cases of grade Ⅲ (50%), 8 cases of grade Ⅳ (40%), and 2 cases of grade Ⅴ (10%). Then, the strategy of diagnosis and treatment for blunt high-grade pancreatic trauma was summarized. The diagnostic rate of CT was 78.9%. Finally, 17 cases (85%) were cured and 3 cases (15%) died. Among the 10 patients with grade Ⅲ pancreatic injury, 7 cases received distal pancreatectomy and splenectomy, 1 case received distal pancreatectomy with spleen preserved, 1 case received pancreatic duct stent placement under endoscopic retrograde cholangiopancreatography (ERCP) and percutaneous catheter drainage (PCD), and 1 case received only PCD. Among 8 cases of grade Ⅳ, 3 cases underwent Roux-en-Y pancreaticojejunostomy, 1 case received distal pancreatectomy and splenectomy, 1 case underwent distal pancreatectomy with spleen preserved, 2 cases received necrotic tissue removal+external drainage of pancreatic duct+abdominal drainage, and 1 case received exploratory laparotomy and gauze packing hemostasis. For 2 cases of grade Ⅴ, 1 underwent pylorus preserving pancreaticoduodenectomy, and the other case underwent pancreaticoduodenectomy combined with right hemicolectomy and splenectomy. Therefore, the treatment of blunt high-grade pancreatic trauma should follow the individualized treatment strategy, pay attention to the control of bleeding, extensive external drainage, appropriate debridement and resection and rational application of damage control surgery, select appropriate patients for conservative treatment, and ultimately benefit the patient.

On the correspondence of deviances and maximum-likelihood and interval estimates from log-linear to logistic regression modelling

Consider a set of categorical variables P where at least one, denoted by Y, is binary. The log-linear model that describes the contingency table counts implies a logistic regression model, with outcome Y. Extending results from Christensen (1997, Log-linear models and logistic regression, 2nd edn. New York, NY, Springer), we prove that the maximum-likelihood estimates (MLE) of the logistic regression parameters equals the MLE for the corresponding log-linear model parameters, also considering the case where contingency table factors are not present in the corresponding logistic regression and some of the contingency table cells are collapsed together. We prove that, asymptotically, standard errors are also equal. These results demonstrate the extent to which inferences from the log-linear framework translate to inferences within the logistic regression framework, on the magnitude of main effects and interactions. Finally, we prove that the deviance of the log-linear model is equal to the deviance of the corresponding logistic regression, provided that no cell observations are collapsed together when one or more factors in P ∖ { Y } become obsolete. We illustrate the derived results with the analysis of a real dataset.

Genetic Profiling of Breast Cancer with and Without Preexisting Metabolic Disease

Breast cancer is the most commonly diagnosed cancer and the leading cause of cancer death among women. Various mechanisms are involved in the initiation and progression of breast cancer. Metabolic dysregulation has been associated with increasing breast cancer incidence and mortality. However, little is known about how metabolic disease regulates the development and progression of breast cancer at the molecular level. Here, using a hybridization capture-based panel including 124 cancer-associated genes, we performed targeted next-generation sequencing of tumor tissues and matched blood samples from 20 postmenopausal patients with primary breast cancer, in which 6 cases suffered from preexisting metabolic disorders including hypertension, type 2 diabetes, and coronary heart disease. We took only the protein-altering variants and identified 170 somatic mutations of 59 genes. Among these, 40 mutated genes were found in the metabolic disease group, and 33 mutated genes were found in the non-metabolic disease group. Importantly, nonsynonymous mutations of 26 genes (MSH3, BRAF, MLH3, MTOR, DDR2, ALK, etc.) were uniquely present in the metabolic disease group. Gene ontology (GO) and Kyoto Encyclopedia of Genes and Genomes enrichment analysis were performed to investigate biological functions and key pathways of somatic mutations. TP53, PIK3CA, and PTEN were the top three commonly mutated genes at a higher frequency compared with the Cancer Genome Atlas (TCGA) data, and several novel but infrequent mutations in other genes were also found. Although further studies are required to validate these variants, our results are the first to suggest a specific molecular profile of breast cancer with preexisting metabolic disease.

[Analysis of prognostic factors for hyperamylasemia following pancreaticoduodenectomy]

Objective: To investigate the prognostic factors of hyperamylasemia following pancreaticoduodenectomy (PD) . Methods: Clinical data of 359 patients were collected prospectively who underwent PD by the same group at Changhai Hospital of Navy Medical University from January 2017 to June 2018.There were 212 males and 147 females.The median age was 63 years old (range: 23 to 82 years old) .According to whether the patient's serum amylase was greater than 120 U/L at 0 or 1 day after surgery,the patients were divided into hyperamylasemia group and non-hyperamylasemia group. Univariate analysis and multivariate analysis were used to find out the prognostic factors of hyperamylasemia after PD. Results: Of the 359 patients, 238 cases (66.3%) developed hyperamylasemia.The incidence rate of clinically related pancreatic fistula (15.1% vs.2.5%, P<0.01) , grade B/C post pancreatectomy hemorrhage (8.8% vs. 2.5%, P<0.01) , and surgical site infection (9.2% vs. 3.3%, P=0.04) was significantly higher in the hyperamylasemia group.The severity of complications (CD grade≥Ⅲ: 11.3% vs.4.1%, P=0.023) and postoperative hospital stay (11 days vs. 9 days, P=0.001) were higher in the hyperamylasemia group.In the multivariate analysis, the main pancreatic duct diameter (MPD) ≤3 mm (OR=4.469, 95% CI: 2.563-7.793, P<0.01) , pathological type of disease (pancreatic cancer or pancreatitis) (OR=0.230, 95% CI: 0.122-0.436, P<0.01) and soft texture of pancreas (OR=3.297, 95%CI: 1.930-5.635, P<0.01) were independent prognostic factors for hyperamylasemia. Conclusions: Post-PD hyperamylasemia increased the incidence and severity of postoperative complications after PD.MPD≤3 mm, soft texture of pancreas and pathological type of disease were independent prognostic factors of hyperamylasemia.

Interferon-stimulated gene 15 expression in systemic lupus erythematosus : Diagnostic value and association with lymphocytopenia

BACKGROUND

The aim of this study was to (a) assess the relationship between interferon-stimulated gene 15 (ISG15) expression and clinical manifestations of systemic lupus erythematosus (SLE) and (b) investigate the diagnostic value of ISG15 in SLE.

PATIENTS AND METHODS

The study comprised 28 patients newly diagnosed with SLE, 10 patients with undifferentiated connective tissue disease, and 22 healthy volunteers. Of the SLE patients, 14 were chosen randomly to be followed up for 4 weeks. ISG15 expression in whole blood cells was determined by quantitative polymerase chain reaction. Clinical and laboratory parameters were recorded at baseline and after treatment.

RESULTS

The ISG15 mRNA level was higher in whole blood cell counts of SLE patients when compared with the disease control and healthy control groups. Moreover, it was correlated with SLE disease activity as assessed via the SLE disease activity index, serositis, and anemia at baseline. ISG15 expression correlated with lymphocytopenia in active SLE patients before treatment. On receiver operating characteristic curve analysis, the area under the curve for ISG15 expression was 0.826 (p = 0.000015).

CONCLUSION

ISG15 expression is relatively high in SLE patients and correlates with disease activity before treatment. ISG15 expression is higher in SLE patients with lymphocytopenia before treatment.

Clofazimine improves clinical outcomes in multidrug-resistant tuberculosis: a randomized controlled trial

OBJECTIVES

We carried out a randomized multicentre study in China to investigate whether the clofazimine would improve the efficacy of the standardized regimen in patients with multidrug-resistant tuberculosis (MDR-TB).

METHODS

Patients with MDR-TB managed in 17 TB specialist hospitals in China between September 2009 and September 2011 were randomly assigned to the treatment groups at enrolment. In the intervention group, 100 mg clofazimine per day was added to the standardized regimen. The primary outcome was the proportion of patients with successful outcomes.

RESULTS

From the 156 patients that were screened, 74 were assigned to the control group and 66 to the clofazimine group. Of the 66 cases analysed for clinical outcome in the clofazimine group, 36 patients were cured, and seven completed treatment, yielding a favourable outcome rate of 65.1%. The proportion of patients with favourable outcomes receiving the control regimen was 47.3% (35/74), which was significantly lower than that in the clofazimine group (p 0.034, relative risk 0.661, 95% CI 0.243-0.949).

CONCLUSIONS

The addition of clofazimine to the standard regimen improved the treatment of MDR-TB.

Assessment of left atrial function and dyssynchrony by real time three-dimensional echocardiography predicts recurrence of paroxysmal atrial fibrillation after radiofrequency ablation

OBJECTIVE

Left atrial volume and function are associated with recurrence of paroxysmal atrial fibrillation (AF) after radiofrequency ablation. A relationship between left atrial mechanical dyssynchrony and AF recurrence is presently unclear. The aim of this study was to investigate whether left atrial volume, function, and dyssynchrony were associated with AF recurrence in patients with normal left ventricular function, and normal or mildly enlarged left atrium, if assessed by the Real-time three-dimensional echocardiography (3DE).

PATIENTS AND METHODS

We included 88 patients with AF who had their first pulmonary vein isolation. There were 67 patients without and 21 patients with AF recurrence after radiofrequency ablation. Real-time 3DE was performed in the sinus rhythm the day before radiofrequency ablation. Left atrial volumes (maximum, minimum and preA), functions (passive, active and reservoir) and dyssynchrony were calculated. The latter was quantified by the standard deviation of time to minimum systolic volume (Tmsv-SD) from the end-diastole.

RESULTS

There was no difference between left atrial volume and function in patients with or without AF recurrence. However, significant differences in left atrial Tmsv-SD were observed in patients with AF recurrence.

CONCLUSIONS

In patients with normal left ventricular function, and normal/mildly enlarged left atrium, left atrial Tmsv-SD assessment by Real-time 3DE is a useful predictor of AF recurrence after radiofrequency ablation.

[Epidemic situation of imported malaria in Chengdu City from 2012 to 2016]

Objective To understand the malaria epidemic situation in Chengdu City, so as to provide the evidence for effectively carrying out the malaria elimination work. Methods The data of imported malaria in Chengdu City from 2012 to 2016 were collected from the Disease Surveillance Information Reporting System of Chinese Center for Disease Control and Prevention and analyzed respectively. Results A total of 240 imported malaria cases were reported in Chengdu City from 2012 to 2016. In detail, 68.75% of the cases were falciparum malaria cases, 20.41% were vivax malaria cases, 2.50% were quartan malaria cases, 6.25% were ovale malaria cases, and 2.08% were mixed Plasmodium infections. Among them three patients died, with a mortality of 1.25%. All of the cases were infected overseas, among which 224 patients returned from Africa and 16 patients from Southeast Asia. The annual average morbidity was 0.28/100 000, and there was a significantly difference among annual average morbidities (χ² = 23.87, P < 0.001). There were malaria cases reported in every month, and no significantly difference among seasons (χ² = 0.833, P > 0.05). Conclusion The number of overseas imported malaria in Chengdu City increases year by year. The effective measures to control the overseas imported malaria should be strengthened to consolidate the achievements of malaria elimination.

Phylogenetic relationships and divergence dates of softshell turtles (Testudines: Trionychidae) inferred from complete mitochondrial genomes

The softshell turtles (Trionychidae) are one of the most widely distributed reptile groups in the world, and fossils have been found on all continents except Antarctica. The phylogenetic relationships among members of this group have been previously studied; however, disagreements regarding its taxonomy, its phylogeography and divergence times are still poorly understood as well. Here, we present a comprehensive mitogenomic study of softshell turtles. We sequenced the complete mitochondrial genomes of 10 softshell turtles, in addition to the GenBank sequence of Dogania subplana, Lissemys punctata, Trionyx triunguis, which cover all extant genera within Trionychidae except for Cyclanorbis and Cycloderma. These data were combined with other mitogenomes of turtles for phylogenetic analyses. Divergence time calibration and ancestral reconstruction were calculated using BEAST and RASP software, respectively. Our phylogenetic analyses indicate that Trionychidae is the sister taxon of Carettochelyidae, and support the monophyly of Trionychinae and Cyclanorbinae, which is consistent with morphological data and molecular analysis. Our phylogenetic analyses have established a sister taxon relationship between the Asian Rafetus and the Asian Palea + Pelodiscus + Dogania + Nilssonia + Amyda, whereas a previous study grouped the Asian Rafetus with the American Apalone. The results of divergence time estimates and area ancestral reconstruction show that extant Trionychidae originated in Asia at around 108 million years ago (MA), and radiations mainly occurred during two warm periods, namely Late Cretaceous-Early Eocene and Oligocene. By combining the estimated divergence time and the reconstructed ancestral area of softshell turtles, we determined that the dispersal of softshell turtles out of Asia may have taken three routes. Furthermore, the times of dispersal seem to be in agreement with the time of the India-Asia collision and opening of the Bering Strait, which provide evidence for the accuracy of our estimation of divergence time. Overall, the mitogenomes of this group were used to explore the origin and dispersal route of Trionychidae and have provided new insights on the evolution of this group.

Primary cilia integrate hedgehog and Wnt signaling during tooth development

Many ciliopathies have clinical features that include tooth malformations but how these defects come about is not clear. Here we show that genetic deletion of the motor protein Kif3a in dental mesenchyme results in an arrest in odontogenesis. Incisors are completely missing, and molars are enlarged in Wnt1(Cre+)Kif3a(fl/fl) embryos. Although amelogenesis and dentinogenesis initiate in the molar tooth bud, both processes terminate prematurely. We demonstrate that loss of Kif3a in dental mesenchyme results in loss of Hedgehog signaling and gain of Wnt signaling in this same tissue. The defective dental mesenchyme then aberrantly signals to the dental epithelia, which prompts an up-regulation in the Hedgehog and Wnt responses in the epithelia and leads to multiple attempts at invagination and an expanded enamel organ. Thus, the primary cilium integrates Hedgehog and Wnt signaling between dental epithelia and mesenchyme, and this cilia-dependent integration is required for proper tooth development.

Enhanced myeloid differentiation factor 88 promotes tumor metastasis via induction of epithelial-mesenchymal transition in human hepatocellular carcinoma

Metastasis is the leading cause of death in patients with hepatocellular carcinoma (HCC) after curative resection. Therefore, it is critical to understand the mechanisms underlying tumor metastasis in HCC. We have previously shown that elevated expression of myeloid differentiation factor 88 (MyD88) may promote tumor growth and metastasis in HCC. In this study, we reported that enhanced expression of MyD88 promoted epithelial–mesenchymal transition (EMT) properties and tumor-initiating capabilities in HCC cells. MyD88 was found to be able to interact with p85, a regulatory subunit of phosphoinositide 3-kinase (PI3-K), independent of TLR/IL-1R-mediated response and caused PI3-K/v-akt murine thymoma viral oncogene homolog (Akt) activation, which resulted in subsequent phosphorylation of glycogen synthase kinase-3β and stabilization of Snail, a critical EMT mediator. Consistently, we observed a significant correlation between MyD88 expression and p-Akt levels in a cohort of HCC patients, and found that the combination of these two parameters have better prognostic value for HCC patients. Taken together, these results suggest that elevated MyD88 may facilitate HCC metastasis by promoting EMT properties and tumor-initiating capabilities via PI3–K/Akt pathway.

gamma-secretase inhibitor induces adipogenesis of adipose-derived stem cells by regulation of Notch and PPAR-gamma

OBJECTIVE

To determine the inhibitory effect and mechanism of Notch signalling on adipogenesis of mouse adipose-derived stem cells (mASCs).

MATERIALS AND METHODS

Varied concentrations of N-[N-(3,5-difluorophenacetyl)-l-alanyl]-S-phenylglycine t-butylester (DAPT) were added to mASCs 3 days before adipogenic induction with insulin-containing differentiation medium. The process of adipogenesis and ability of lipid droplet accumulation were analysed using oil red-O staining. The Notch signalling pathway (Notch-1, -2, -3, -4, Hes-1 and Hey-1) and adipogenesis-related factors (PPAR-gamma, DLK-1/Pref-1 and Acrp) were tested using real-time PCR, Western blot analysis and immunofluorescence staining assays.

RESULTS

We demonstrated that Notch-2-Hes-1 signalling pathway was inhibited dose-dependently by DAPT in mASCs. In addition, transcription of PPAR-gamma was promoted by DAPT before adipogenic induction, while inhibitor of adipogenesis DLK-1/Pref-1 was further depressed. At early stages of differentiation (2-4 days), adipogenesis in mASCs was advanced and significantly enhanced in 5 and 10 mum DAPT pre-treated cases. On day 4, in differentiated mASCs cases with DAPT pre-treatment, we also found promotion of activation of de-PPAR-gamma and depression of HES-1, DLK-1/Pref-1 mRNA and protein expression.

CONCLUSIONS

We conclude that blocking Notch signalling with DAPT enhances adipogenesis of differentiated mASCs at an early stage. It may be due to depression of DLK-1/Pref-1 and promotion of de-PPAR-gamma activation, which work through inhibition of Notch-2-Hes-1 pathway by DAPT.

Identification of osteo-adipo progenitor cells in fat tissue

OBJECTIVES

In this study, a group of cells that expressed both osteogenic and adipogenic characters was identified from murine adipose stromal cells.

MATERIALS AND METHODS

These cells could be enriched in the Sca-1-1 population and express both osteogenic and adipogenic genes. Osteogenic induction enhanced expression of osteogenic genes and inhibited expression of adipogenic genes, while adipogenic induction enhanced expression of adipogenic genes and inhibited expression of osteogenic genes. These cells have been called osteo-adipo progenitors (OAPs).

RESULTS

OAPs expressed transcription factor runt-related transcription factor 2 (RUNX2) and peroxisome proliferator-activated receptor-gamma (PPAR-gamma) proteins in cytoplasm. When OAPs were cultured in adipogenic medium, PPAR-gamma moved to the nucleus and the cells differentiated into adipocytes, while the RUNX2 remained in the cytoplasm. In contrast, when OAPs were cultured in osteogenic medium, RUNX2 moved to the nucleus and the cells differentiated to osteocytes, while the PPAR-gamma remained in the cytoplasm.

CONCLUSIONS

These experiments suggest that osteoblasts and adipocytes share a common predecessor, the OAP, in murine adipose stromal cells.

Odontogenic tumours: a retrospective study of 1642 cases in a Chinese population

A total of 1642 odontogenic tumour cases retrieved from the files of the College of Stomatology, Sichuan University, China were retrospectively analyzed for gender, age, tumour site and relative frequency of various types, and the data compared with that of previous reports. The final diagnosis in each case was based on the WHO 2005 histopathological classification of odontogenic tumours. Of these tumours 1592 (97.0%) were benign and 50 (3.0%) were malignant. Ameloblastoma (40.3%) was the most frequent type, followed by keratocystic odontogenic tumour (35.8%), odontoma (4.7%) and odontogenic myxoma (4.6%). The mean age of the patients was 32.1, with a wide range (3-84 years). The male-female ratio and maxilla-mandible ratio were 1.4:1 and 1:4.0, respectively. Ameloblastoma and keratocystic odontogenic tumours, important indications of extensive surgical procedures, are not considered rare in this Chinese population, whereas odontoma is uncommon.

Prevalence of factor V Leiden and prothrombin G20210A mutations in Chinese patients with deep venous thrombosis and pulmonary embolism

Venous thromboembolism (VTE) is a common vascular disease that results in two major clinical manifestations: deep venous thrombosis (DVT) and pulmonary embolism (PE). Several genetic risk factors, especially factor V Leiden and prothrombin G20210A mutations have been reported to be related to VTE in Caucasians, but the relationship remains controversial in other populations. Thus, the objective of the present study was to compare the frequency of the two mutations and also to investigate whether acquired risk factors other than genetic mutations may play a different role in Chinese VTE patients. Thirty-five patients were diagnosed with DVT concomitant PE, 178 patients with DVT, 54 patients with PE and 102 control subjects were recruited. The mutation was determined by the polymerase chain reaction-restriction fragment length polymorphism method. Of all subjects, none was a carrier of factor V Leiden or prothrombin G20210A mutations. The frequency of surgery was significantly higher in the PE group than that in other groups. There was no significant difference among the three groups in other known risk factors. The data presented here indicate that factor V Leiden and prothrombin G20210A mutations are very rare in the Chinese population, and the genetic risk profile of VTE in the Chinese population is different from that in Caucasians.

Interactions of the antimicrobial peptide Ac-FRWWHR-NH2 with model membrane systems and bacterial cells

The acetylated and amidated hexapeptide FRWWHR (combi-2), previously identified by combinatorial chemistry methods, shows strong antimicrobial activity. The binding of the peptide to 1-palmitoyl-2-oleoyl-sn-glycero-3-[(phospho-rac-(1-glycerol)] (POPG) and 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphocholine (POPC) vesicles was studied using fluorescence spectroscopy and isothermal titration calorimetry (ITC). Differential scanning calorimetry (DSC) with dipalmitoylphosphatidylcholine (DPPC) and dipalmitoylphosphatidylglycerol (DPPG) multilamellar vesicles was performed to determine changes in the lipid phase behaviour upon binding the peptide. Two-dimensional proton nuclear magnetic resonance (NMR) spectroscopy, to solve the bound peptide structure, was performed in the presence of dodecylphosphatidylcholine (DPC) and sodium dodecyl sulphate (SDS) micelles. The fluorescence, ITC and DSC studies indicate that the peptide interacts preferentially with lipid vesicles containing negatively charged head groups. Conformational information determined using NMR indicate that the combi-2 peptide adopts a coiled amphipathic conformation when bound to SDS and DPC micelles. Leakage assays indicate that the peptide is not very efficient at causing leakage from calcein-filled large unilamellar vesicles comprised of POPG/POPC (1 : 1). The rapid passage of either the fluorescent-tagged peptides combi-2 or the previously studied peptide Ac-RRWWRF-NH(2) (combi-1) into Escherichia coli and Staphylococcus aureus suggests that instead of membrane disruption, the main bactericidal site of action of these peptides might be located inside bacteria.

The structure of the antimicrobial peptide Ac-RRWWRF-NH2 bound to micelles and its interactions with phospholipid bilayers

The hexapeptide Ac-RRWWRF-NH2 has earlier been identified as a potent antimicrobial peptide by screening synthetic combinatorial hexapeptide libraries. In this study, it was found that this peptide had a large influence on the thermotropic phase behavior of model membranes containing the negatively charged headgroup phosphatidylglycerol, a major component of bacterial membranes. In contrast, differential scanning calorimetry showed that it had little effect on model membranes containing the zwitterionic phosphatidylcholine headgroup, the main component of erythrocyte membranes. This behavior is consistent with its biological activity and with its affinity to these membranes as determined by titration calorimetry, implying that peptide-lipid interactions play an important role in this process. The structure of this peptide bound to membrane-mimetic sodium dodecyl sulfate (SDS) and dodecylphosphocholine micelles has been determined using conventional two-dimensional nuclear magnetic resonance methods. It forms a marked amphipathic structure in SDS with its hydrophobic residues on one side of the structure and with the positively charged residues on the other side. This amphipathic structure may allow this peptide to penetrate deeper into the interfacial region of negatively charged membranes, leading to local membrane destabilization. Knowledge about the importance of electrostatic interactions of Arg and the role of Trp residues as a membrane interface anchor will provide insight into the future design of potent antimicrobial peptidomimetics.

The CH3 N Diradical: Experimental and Theoretical Determinations of the Ionization Energies

Pyrolysis of CH3 N3 under the protection of NO generates a continuous methylnitrene CH3 N diradical beam that enables the ionization energies of different ionic states of the CH3 N diradical to be determined by HeI photoelectron spectroscopy (PES; see spectrum) and both ab initio and density functional theory (DFT) calculations. The ab initio and DFT results are in excellent agreement with the PES experiment and show that the CH3 N diradical has C3v symmetry and the ground state of the CH3 N radical cation is the (2) E state.

Stereotactic biopsy for intracranial space-occupying lesions: clinical analysis of 550 cases

OBJECT

To investigate the role of stereotactic biopsy in planning the optimal management of intracranial space-occupying lesions.

PATIENTS AND METHODS

Between December 1989 and December 1999, stereotactic biopsy was performed in 550 patients with intracranial mass lesions that were deep-seated or located in the functional area. There were 340 males and 210 females, and their ages ranged from 4 to 75 years. All the procedures were done under local anesthesia with a Leksell stereotactic system. A CT scan was used to determine the coordinates in the first 420 cases and the Aero Tech Stereotactic Surgical Plan System in the subsequent 130 patients.

RESULTS

Brain tumors were diagnosed pathologically in 475 patients (86.4%), inflammatory process in 44 (8.0%), other lesions in 12 (2.2%) and no conclusive diagnosis was found in 19 (3.4%). The overall positive rate of biopsy was 96.6%, and the positive rate for brain tumor was 86.4%. Intracranial hematomas after biopsy were found in 13 cases (2.4%). Seizures occurred during the operation in 7 cases (1.2%), and slight and transient neurological deficits were found in 23 cases (4.2%). There were no deaths or other serious complications.

CONCLUSIONS

The results suggest that the stereotactic biopsy is a reliable method to obtain histopathological diagnosis of intracranial mass lesions, and it is also of great help in selecting the appropriate management.

Dissection of the two transferase activities of the Pasteurella multocida hyaluronan synthase: two active sites exist in one polypeptide

Type A Pasteurella multocida, an animal pathogen, employs a hyaluronan [HA] capsule to avoid host defenses. PmHAS, the 972-residue membrane-associated hyaluronan synthase, catalyzes the transfer of both GlcNAc and GlcUA to form the HA polymer. To define the catalytic and membrane-associated domains, pmHAS mutants were analyzed. PmHAS1-703 is a soluble, active HA synthase suggesting that the carboxyl-terminus is involved in membrane association of the native enzyme. PmHAS1-650 is inactive as a HA synthase, but retains GlcNAc-transferase activity. Within the pmHAS sequence, there is a duplicated domain containing a short motif, Asp-Gly-Ser, that is conserved among many beta-glycosyltransferases. Changing this aspartate in either domain to asparagine, glutamate, or lysine reduced the HA synthase activity to low levels. The mutants substituted at residue 196 possessed GlcUA-transferase activity while those substituted at residue 477 possessed GlcNAc-transferase activity. The Michaelis constants of the functional transferase activity of the various mutants, a measure of the apparent affinity of the enzymes for the precursors, were similar to wild-type values. Furthermore, mixing D196N and D477K mutant proteins in the same reaction allowed HA polymerization at levels similar to the wild-type enzyme. These results provide the first direct evidence that the synthase polypeptide utilizes two separate glycosyltransferase sites.

A retrospective survey of mucocutaneous manifestations of HIV infection in Malaysia: analysis of 182 cases

A retrospective analysis of 182 HIV positive Malaysians was done in two centers, the University Hospital Kuala Lumpur (UHKL) and the General Hospital Kuala Lumpur (GHKL) from March 1997 to February 1998. Demographic and clinical data were analyzed. The analysis showed that 130 out of 182 patients had mucocutaneous disorders (71.4%). In the study there were 125 males (96.2%) and 5 females (3.8%). The majority of the patients were in the age group from 20 to 50 years. The patients who presented with mucocutaneous disease also had low CD4+ T lymphocyte counts, and most of them had AIDS defining illnesses. The number of cases with generalized hyperpigmentation was very high (35.7%), followed by papular eruptions (29.1%) and xerosis (27.5%). Seborrheic dermatitis was seen in 19.2% of the cases and psoriasis in 7.7%. The most common infections were oral candida 35.7%, tinea corporis and onychomycosis 9.9%, and herpes infection 4.3%. However, mucocutaneous manifestations of Kaposi's sarcoma were rare. The results suggested that mucocutaneous findings are useful clinical predictors of HIV infection or a sign of the presence of advanced HIV infection.

Mucocutaneous manifestations of HIV infection: a retrospective analysis of 145 cases in a Chinese population in Malaysia

BACKGROUND

Mucocutaneous lesions directly related to human immunodeficiency virus (HIV) infection usually present as initial manifestations of immune deficiency. The most common mucocutaneous lesions are Kaposi's sarcoma, histoplasmosis, oro-esophageal candidiasis, oral hairy leukoplakia, and, in Asia, Penicillium marneffei infection. Non-HIV-related skin lesions, such as psoriasis, seborrheic dermatitis, and nodular prurigo, may be the initial presentation among HIV infected patients attending outpatient clinics.

METHODS

A retrospective analysis was performed on 145 HIV-positive Malaysians of Chinese descent from two centers at the University Hospital Kuala Lumpur (UHKL) and the General Hospital Kuala Lumpur (GHKL) from March 1997 to February 1998. Demographic data and clinical data were analyzed.

RESULTS

The analysis showed that 104 out of 145 patients had mucocutaneous disorders (71.7%). In the study, there were 100 men (96.2%) and four women (3.8%). The majority of patients were in the age group 20-50 years. The patients who presented with mucocutaneous disease also had low CD4+ T-lymphocyte counts and most had acquired immunodeficiency syndrome (AIDS) defining illness. The number of cases with generalized hyperpigmentation was very high in the group (35.9%), followed by nodular prurigo (29.7%) and xerosis (27.6%). Seborrheic dermatitis was seen in 20.7% of cases, with psoriasis in 8.3%. The most common infections were oral candidiasis (35.9%), tinea corporis and onychomycosis (9.7%), and herpes infection (5.5%); however, mucocutaneous manifestations of Kaposi's sarcoma were rare.

CONCLUSIONS

The results suggest that mucocutaneous findings are useful clinical predictors of HIV infection or signs of the presence of advanced HIV infection.

Measurement of neutrons produced in an intermediate energy heavy ion reaction using an activation technique

The fluence rate, energy, and angular distributions of neutrons produced by the reaction of 50 MeV/u 12C ions on a thick copper target around the experimental target in the physics experimental hall of Heavy Ion Research Facility of Lanzhou were studied. The neutrons were measured with threshold activation detectors. Aluminum, fluorine, carbon, aluminum, and indium activation samples were used to measure neutrons with energies greater than 7 MeV, 11 MeV, 20 MeV, 50 MeV, and thermal neutrons, respectively. The fluence rate, energy and angular distributions of neutrons, total neutron yield of 12C ions, and the emission rate in the forward direction of neutrons with energies over 11 MeV and 20 MeV were obtained.

Identification and molecular cloning of a unique hyaluronan synthase from Pasteurella multocida

Type A Pasteurella multocida, a prevalent animal pathogen, employs a hyaluronan [HA] polysaccharide capsule to avoid host defenses. We utilized transposon insertional mutagenesis to identify the P. multocida HA synthase, the enzyme that polymerizes HA. A DNA fragment from a wild-type genomic library could direct HA production in vivo in Escherichia coli, a bacterium that normally does not produce HA. Analysis of truncated plasmids derived from the original clone indicated that an open reading frame encoding a 972-residue protein was responsible for HA polymerization. This identification was confirmed by expression cloning in E. coli; we observed HA capsule formation in vivo and detected activity in membrane preparations in vitro. The polypeptide size was verified by photoaffinity labeling of the native P. multocida HA synthase with azido-UDP sugar analogs. Overall, the P. multocida sequence is not very similar to the other known HA synthases from streptococci, PBCV-1 virus, or vertebrates. Instead, a portion of the central region of the new enzyme is more homologous to the amino termini of other bacterial glycosyltransferases that produce different capsular polysaccharides or lipopolysaccharides. In summary, we have discovered a unique HA synthase that differs in sequence and predicted topology from the other known enzymes.

Hyaluronan synthase of chlorella virus PBCV-1

Sequence analysis of the 330-kilobase genome of the virus PBCV-1 that infects a chlorella-like green algae revealed an open reading frame, A98R, with similarity to several hyaluronan synthases. Hyaluronan is an essential polysaccharide found in higher animals as well as in a few pathogenic bacteria. Expression of the A98R gene product in Escherichia coli indicated that the recombinant protein is an authentic hyaluronan synthase. A98R is expressed early in PBCV-1 infection and hyaluronan is produced in infected algae. These results demonstrate that a virus can encode an enzyme capable of synthesizing a carbohydrate polymer and that hyaluronan exists outside of animals and their pathogens.

[The effect of alkalinity of methylation reagent on isomerization and degradation of polyunsaturated fatty acids with pyrolysis gas chromatography]

Simultaneous pyrolysis and methylation gas chromatography (SPM-GC) is a fast analytical method which was developed in recent years. However, the strong alkalinity of tetramethylammonium hydroxide (TMAH) may result in the isomerization and degradation of polyunsaturated fatty acids in oils and fats during analysis. This paper describes the application of SPM-GC to polyunsaturated fatty acids in soybean oil and the isomerization and degradation may be prevented by choosing the optimum proportion of TMAH to methanol which is 1:50 (pH 8.8). With this chosen optimum proportion there were no detectable isomerized and degraded peaks in the chromatograms. Pyrograms were obtained by interfacing a Curie-point pyrolyser to a Shimadzu GC-14A gas chromatograph equipped with a flame ionisation detector. A capillary column (FFAP) was used. All of the pyrolysis products were identified by mass spectrometry which was carried out with a Varian 3400 gas chromatograph interfaced to a Finnigan SSQ 710 mass spectrometer using electron impact ionisation (70 eV). This method is simpler and more convenient than both the methods "neutralization of acid" and "simultaneous injection of the sample and a short chain fatty acid methylester" reported in the previous papers.