Using machine learning techniques to predict the risk of osteoporosis based on nationwide chronic disease data

Osteoporosis is a major public health concern that significantly increases the risk of fractures. The aim of this study was to develop a Machine Learning based predictive model to screen individuals at high risk of osteoporosis based on chronic disease data, thus facilitating early detection and personalized management. A total of 10,000 complete patient records of primary healthcare data in the German Disease Analyzer database (IMS HEALTH) were included, of which 1293 diagnosed with osteoporosis and 8707 without the condition. The demographic characteristics and chronic disease data, including age, gender, lipid disorder, cancer, COPD, hypertension, heart failure, CHD, diabetes, chronic kidney disease, and stroke were collected from electronic health records. Ten different machine learning algorithms were employed to construct the predictive mode. The performance of the model was further validated and the relative importance of features in the model was analyzed. Out of the ten machine learning algorithms, the Stacker model based on Logistic Regression, AdaBoost Classifier, and Gradient Boosting Classifier demonstrated superior performance. The Stacker model demonstrated excellent performance through ten-fold cross-validation on the training set and ROC curve analysis on the test set. The confusion matrix, lift curve and calibration curves indicated that the Stacker model had optimal clinical utility. Further analysis on feature importance highlighted age, gender, lipid metabolism disorders, cancer, and COPD as the top five influential variables. In this study, a predictive model for osteoporosis based on chronic disease data was developed using machine learning. The model shows great potential in early detection and risk stratification of osteoporosis, ultimately facilitating personalized prevention and management strategies.

[Correlation of MYB/NFIB gene fusion with the grade and prognosis of head and neck adenoid cystic carcinoma and the concordance of two detection methods]

Objective: To explore the correlation between MYB/NFIB gene fusion and clinicopathological features such as tumor grade and prognosis of head and neck adenoid cystic carcinoma (ACC), and to assess the concordant rate of fluorescent in situ hybridization (FISH) with MYB and NFIB immunohistochemistry. Methods: FISH detection of MYB/NFIB gene fusion was performed on 48 head and neck ACC cases and 15 non-ACC salivary gland tumors at National Cancer Center/National Clinical Research Center for Cancer/Cancer Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China during April 2014 and January 2020. ACC cases were divided into grade Ⅰ-Ⅱ, grade Ⅲ and high-grade transformation, according to pathological grading criteria. Prognosis, FISH results and other clinicopathological characteristics were analyzed. MYB and NFIB immunohistochemistry was performed on the 48 ACC and 15 non-ACC cases. The diagnostic accuracy of FISH and immunohistochemistry was compared. Results: FISH detected MYB/NFIB gene fusion in 41.7% (20/48) of the ACC. Its positive rate was inversely correlated with higher pathological grades (P=0.036). The higher histological grade was linked to worse progression-free survival (P=0.024), whereas there was no correlation between the status of gene fusion detected by FISH and progression-free survival (P=0.536). FISH didnot detect MYB/NFIB gene fusion in 15 non-ACC salivary gland tumors The specificity of diagnosing ACC is 100% for both FISH detection of gene fusion and immunohistochemical detection of MYB expression. However, the sensitivity for both methods was only about 41.7%, respectively. By combining FISH and MYB immunohistochemistry, the sensitivity for diagnosing ACC was increased to 66.7%. Conclusions: MYB/NFIB gene fusion has a lower detection rate in grade Ⅲ ACC and high-grade transformation ACC. Meanwhile gene fusion status is not correlated with prognosis. The sensitivity for diagnosing ACC can be improved by combining FISH and MYB immunohistochemistry.

Machine learning for the prediction of postoperative nosocomial pulmonary infection in patients with spinal cord injury

PURPOSE

The purpose of this study was to establish the best prediction model for postoperative nosocomial pulmonary infection through machine learning (ML) and assist physicians to make accurate diagnosis and treatment decisions.

METHODS

Patients with spinal cord injury (SCI) who admitted to a general hospital between July 2014 and April 2022 were included in this study. The data were segmented according to the ratio of seven to three, 70% were randomly selected to train the model, and the other 30% were used for testing. We used LASSO regression to screen the variables, and the selected variables were used in the construction of six different ML models. Shapley additive explanations and permutation importance were used to explain the output of the ML models. Finally, sensitivity, specificity, accuracy and area under receiver operating characteristic curve (AUC) were used as the evaluation index of the model.

RESULTS

A total of 870 patients were enrolled in this study, of whom 98 (11.26%) developed pulmonary infection. Seven variables were used for ML model construction and multivariate logistic regression analysis. Among these variables, age, ASIA scale and tracheotomy were found to be the independent risk factors for postoperative nosocomial pulmonary infection in SCI patients. Meanwhile, the prediction model based on RF algorithm performed best in the training and test sets. (AUC = 0.721, accuracy = 0.664, sensitivity = 0.694, specificity = 0.656).

CONCLUSION

Age, ASIA scale and tracheotomy were the independent risk factors of postoperative nosocomial pulmonary infection in SCI. The prediction model based on RF algorithm had the best performance.

Metabolism and senescence in the immune microenvironment of osteosarcoma: focus on new therapeutic strategies

Osteosarcoma is a highly aggressive and metastatic malignant tumor. It has the highest incidence of all malignant bone tumors and is one of the most common solid tumors in children and adolescents. Osteosarcoma tissues are often richly infiltrated with inflammatory cells, including tumor-associated macrophages, lymphocytes, and dendritic cells, forming a complex immune microenvironment. The expression of immune checkpoint molecules is also high in osteosarcoma tissues, which may be involved in the mechanism of anti-tumor immune escape. Metabolism and senescence are closely related to the immune microenvironment, and disturbances in metabolism and senescence may have important effects on the immune microenvironment, thereby affecting immune cell function and immune responses. Metabolic modulation and anti-senescence therapy are gaining the attention of researchers as emerging immunotherapeutic strategies for tumors. Through an in-depth study of the interconnection of metabolism and anti- senescence in the tumor immune microenvironment and its regulatory mechanism on immune cell function and immune response, more precise therapeutic strategies can be developed. Combined with the screening and application of biomarkers, personalized treatment can be achieved to improve therapeutic efficacy and provide a scientific basis for clinical decision-making. Metabolic modulation and anti- senescence therapy can also be combined with other immunotherapy approaches, such as immune checkpoint inhibitors and tumor vaccines, to form a multi-level and multi-dimensional immunotherapy strategy, thus further enhancing the effect of immunotherapy. Multidisciplinary cooperation and integrated treatment can optimize the treatment plan and maximize the survival rate and quality of life of patients. Future research and clinical practice will further advance this field, promising more effective treatment options for patients with osteosarcoma. In this review, we reviewed metabolic and senescence characteristics in the immune microenvironment of osteosarcoma and related immunotherapies, and provide a reference for development of more personalized and effective therapeutic strategies.

Using multiple indicators to predict the risk of surgical site infection after ORIF of tibia fractures: a machine learning based study

Objective

Surgical site infection (SSI) are a serious complication that can occur after open reduction and internal fixation (ORIF) of tibial fractures, leading to severe consequences. This study aimed to develop a machine learning (ML)-based predictive model to screen high-risk patients of SSI following ORIF of tibial fractures, thereby aiding in personalized prevention and treatment.

Methods

Patients who underwent ORIF of tibial fractures between January 2018 and October 2022 at the Department of Emergency Trauma Surgery at Ganzhou People's Hospital were retrospectively included. The demographic characteristics, surgery-related variables and laboratory indicators of patients were collected in the inpatient electronic medical records. Ten different machine learning algorithms were employed to develop the prediction model, and the performance of the models was evaluated to select the best predictive model. Ten-fold cross validation for the training set and ROC curves for the test set were used to evaluate model performance. The decision curve and calibration curve analysis were used to verify the clinical value of the model, and the relative importance of features in the model was analyzed.

Results

A total of 351 patients who underwent ORIF of tibia fractures were included in this study, among whom 51 (14.53%) had SSI and 300 (85.47%) did not. Of the patients with SSI, 15 cases were of deep infection, and 36 cases were of superficial infection. Given the initial parameters, the ET, LR and RF are the top three algorithms with excellent performance. Ten-fold cross-validation on the training set and ROC curves on the test set revealed that the ET model had the best performance, with AUC values of 0.853 and 0.866, respectively. The decision curve analysis and calibration curves also showed that the ET model had the best clinical utility. Finally, the performance of the ET model was further tested, and the relative importance of features in the model was analyzed.

Conclusion

In this study, we constructed a multivariate prediction model for SSI after ORIF of tibial fracture through ML, and the strength of this study was the use of multiple indicators to establish an infection prediction model, which can better reflect the real situation of patients, and the model show great clinical prediction performance.

[Current situation and problems of the clinical application of completely digital workflow in fixed prosthodontics]

Compared with traditional prosthodontic methods, digital prosthodontic technology greatly simplifies the treatment process of patients and improves the accuracy of prosthesis. The fully digital workflow is becoming an important direction of the development of fixed prosthodontics. It can not only effectively improve the efficiency, accuracy and predictability of prosthodontics, but also help the cooperation between multiple disciplines to ensure the systematic treatment. This article systematically discusses the concept process, key technology, material progress and application of completely digital prosthodontic process, as well as the remaining problems, in order to provide reference for its clinical application.

[Value of direct immunohistochemical staining in assisting intraoperative frozen diagnosis of bronchiolar adenoma]

Objective: To explore the feasibility and application value of intraoperative direct immunohistochemical (IHC) staining in improving the diagnosis accuracy in difficult cases of bronchiolar adenoma (BA). Methods: Nineteen cases with single or multiple pulmonary ground-glass nodules or solid nodules indicated by imaging in Cancer Hospital of Chinese Academy of Medical Sciences from January to July 2021 and with difficulty in differential diagnosis at frozen HE sections were selected. In the experimental group, direct IHC staining of cytokeratin 5/6 (CK5/6) and p63 was performed on frozen sections to assist the differentiation of BA from in situ/micro-invasive adenocarcinoma/adenocarcinoma/invasive mucinous adenocarcinoma. In the control group, two pathologists performed routine frozen HE section diagnosis on these 19 cases. The diagnostic results of paraffin sections were used as the gold standard. The sensitivity and specificity of BA diagnosis, consistency with paraffin diagnosis and time used for frozen diagnosis were compared between the experimental group and the control group. Results: The basal cells of BA were highlighted by CK5/6 and p63 staining. There were no basal cells in the in situ/microinvasive adenocarcinoma/adenocarcinoma/invasive mucinous adenocarcinoma. In the experimental group, the sensitivity and specificity with aid of direct IHC staining for BA were 100% and 86.7%, respectively, and the Kappa value of frozen and paraffin diagnosis was 0.732, and these were significantly higher than those in the control group (P<0.05). The average time consumption in the experimental group (32.4 min) was only 7 min longer than that in the control group (25.4 min). Conclusions: Direct IHC staining can improve the accuracy of BA diagnosis intraoperatively and reduce the risk of misdiagnosis, but require significantly longer time. Thus frozen direct IHC staining should be restricted to cases with difficulty in differentiating benign from malignant diseases, especially when the surgical modalities differ based on the frozen diagnosis.

[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.

Prediction of bone metastasis in non-small cell lung cancer based on machine learning

Objective

The purpose of this paper was to develop a machine learning algorithm with good performance in predicting bone metastasis (BM) in non-small cell lung cancer (NSCLC) and establish a simple web predictor based on the algorithm.

Methods

Patients who diagnosed with NSCLC between 2010 and 2018 in the Surveillance, Epidemiology and End Results (SEER) database were involved. To increase the extensibility of the research, data of patients who first diagnosed with NSCLC at the First Affiliated Hospital of Nanchang University between January 2007 and December 2016 were also included in this study. Independent risk factors for BM in NSCLC were screened by univariate and multivariate logistic regression. At this basis, we chose six commonly machine learning algorithms to build predictive models, including Logistic Regression (LR), Decision tree (DT), Random Forest (RF), Gradient Boosting Machine (GBM), Naive Bayes classifiers (NBC) and eXtreme gradient boosting (XGB). Then, the best model was identified to build the web-predictor for predicting BM of NSCLC patients. Finally, area under receiver operating characteristic curve (AUC), accuracy, sensitivity and specificity were used to evaluate the performance of these models.

Results

A total of 50581 NSCLC patients were included in this study, and 5087(10.06%) of them developed BM. The sex, grade, laterality, histology, T stage, N stage, and chemotherapy were independent risk factors for NSCLC. Of these six models, the machine learning model built by the XGB algorithm performed best in both internal and external data setting validation, with AUC scores of 0.808 and 0.841, respectively. Then, the XGB algorithm was used to build a web predictor of BM from NSCLC.

Conclusion

This study developed a web predictor based XGB algorithm for predicting the risk of BM in NSCLC patients, which may assist doctors for clinical decision making.

A practical dynamic nomogram model for predicting bone metastasis in patients with thyroid cancer

PURPOSE

The aim of this study was to established a dynamic nomogram for assessing the risk of bone metastasis in patients with thyroid cancer (TC) and assist physicians to make accurate clinical decisions.

METHODS

The clinical data of patients with TC admitted to the First Affiliated hospital of Nanchang University from January 2006 to November 2016 were included in this study. Demographic and clinicopathological parameters of all patients at primary diagnosis were analyzed. Univariate and multivariate logistic regression analysis was applied to build a predictive model incorporating parameters. The discrimination, calibration, and clinical usefulness of the nomogram were evaluated using the C-index, ROC curve, calibration plot, and decision curve analysis. Internal validation was evaluated using the bootstrapping method.

RESULTS

A total of 565 patients were enrolled in this study, of whom 25 (4.21%) developed bone metastases. Based on logistic regression analysis, age (OR=1.040, P=0.019), hemoglobin (HB) (OR=0.947, P<0.001) and alkaline phosphatase (ALP) (OR=1.006, P=0.002) levels were used to construct the nomogram. The model exhibited good discrimination, with a C-index of 0.825 and good calibration. A C-index value of 0.815 was achieved on interval validation analysis. Decision curve analysis showed that the nomogram was clinically useful when intervention was decided at a bone metastases possibility threshold of 1%.

CONCLUSIONS

This dynamic nomogram, with relatively good accuracy, incorporating age, HB, and ALP, could be conveniently used to facilitate the prediction of bone metastasis risk in patients with TC.

Using Machine Learning Methods to Predict Bone Metastases in Breast Infiltrating Ductal Carcinoma Patients

Breast cancer (BC) was the most common malignant tumor in women, and breast infiltrating ductal carcinoma (IDC) accounted for about 80% of all BC cases. BC patients who had bone metastases (BM) were more likely to have poor prognosis and bad quality of life, and earlier attention to patients at a high risk of BM was important. This study aimed to develop a predictive model based on machine learning to predict risk of BM in patients with IDC. Six different machine learning algorithms, including Logistic regression (LR), Naive Bayes classifiers (NBC), Decision tree (DT), Random Forest (RF), Gradient Boosting Machine (GBM), and Extreme gradient boosting (XGB), were used to build prediction models. The XGB model offered the best predictive performance among these 6 models in internal and external validation sets (AUC: 0.888, accuracy: 0.803, sensitivity: 0.801, and specificity: 0.837). Finally, an XGB model-based web predictor was developed to predict risk of BM in IDC patients, which may help physicians make personalized clinical decisions and treatment plans for IDC patients.

Application of Machine Learning Techniques to Predict Bone Metastasis in Patients with Prostate Cancer

Objective

This study aimed to develop and validate a machine learning model for predicting bone metastases (BM) in prostate cancer (PCa) patients.

Methods

Demographic and clinicopathologic variables of PCa patients in the Surveillance, Epidemiology and End Results (SEER) database from 2010 to 2017 were retrospectively analyzed. We used six different machine learning algorithms, including Decision tree (DT), Random forest (RF), Multilayer Perceptron (MLP), Logistic regression (LR), Naive Bayes classifiers (NBC), and eXtreme gradient boosting (XGB), to build prediction models. External validation using data from 644 PCa patients of the First Affiliated Hospital of Nanchang University from 2010 to 2016. The performance of the models was evaluated using the area under receiver operating characteristic curve (AUC), accuracy score, sensitivity (recall rate) and specificity. A web predictor was developed based on the best performance model.

Results

A total of 207,137 PCa patients from SEER were included in this study. Of whom, 6725 (3.25%) developed BM. Gleason score, Prostate-specific antigen (PSA) value, T, N stage and age were found to be the risk factors of BM. The XGB model offered the best predictive performance among these 6 models (AUC: 0.962, accuracy: 0.884, sensitivity (recall rate): 0.906, and specificity: 0.879). An XGB model-based web predictor was developed to predict BM in PCa patients.

Conclusion

This study developed a machine learning model and a web predictor for predicting the risk of BM in PCa patients, which may help physicians make personalized clinical decisions and treatment strategy for patients.

Machine learning for the prediction of bone metastasis in patients with newly diagnosed thyroid cancer

OBJECTIVES

This study aimed to establish a machine learning prediction model that can be used to predict bone metastasis (BM) in patients with newly diagnosed thyroid cancer (TC).

METHODS

Demographic and clinicopathologic variables of TC patients in the Surveillance, Epidemiology, and End Results database from 2010 to 2016 were retrospectively analyzed. On this basis, we developed a random forest (RF) algorithm model based on machine-learning. The area under receiver operating characteristic curve (AUC), accuracy score, recall rate, and specificity are used to evaluate and compare the prediction performance of the RF model and the other model.

RESULTS

A total of 17,138 patients were included in the study, with 166 (0.97%) developed bone metastases. Grade, T stage, histology, race, sex, age, and N stage were the important prediction features of BM. The RF model has better predictive performance than the other model (AUC: 0.917, accuracy: 0.904, recall rate: 0.833, and specificity: 0.905).

CONCLUSIONS

The RF model constructed in this study could accurately predict bone metastases in TC patients, which may provide clinicians with more personalized clinical decision-making recommendations. Machine learning technology has the potential to improve the development of BM prediction models in TC patients.

Inducing secondary metabolite production of Aspergillus sydowii through microbial co-culture with Bacillus subtilis

Background

The co-culture strategy which mimics natural ecology by constructing an artificial microbial community is a useful tool to activate the biosynthetic gene clusters to generate new metabolites. However, the conventional method to study the co-culture is to isolate and purify compounds separated by HPLC, which is inefficient and time-consuming. Furthermore, the overall changes in the metabolite profile cannot be well characterized.

Results

A new approach which integrates computational programs, MS-DIAL, MS-FINDER and web-based tools including GNPS and MetaboAnalyst, was developed to analyze and identify the metabolites of the co-culture of Aspergillus sydowii and Bacillus subtilis. A total of 25 newly biosynthesized metabolites were detected only in co-culture. The structures of the newly synthesized metabolites were elucidated, four of which were identified as novel compounds by the new approach. The accuracy of the new approach was confirmed by purification and NMR data analysis of 7 newly biosynthesized metabolites. The bioassay of newly synthesized metabolites showed that four of the compounds exhibited different degrees of PTP1b inhibitory activity, and compound N2 had the strongest inhibition activity with an IC₅₀ value of 7.967 μM.

Conclusions

Co-culture led to global changes of the metabolite profile and is an effective way to induce the biosynthesis of novel natural products. The new approach in this study is one of the effective and relatively accurate methods to characterize the changes of metabolite profiles and to identify novel compounds in co-culture systems.

Solvodynamic Printing As A High Resolution Printing Method

Printing techniques are becoming increasingly prevalent in modern manufacturing. However, its biggest drawback is the limit in printing resolution. In this paper, we present solvodynamic printing as a novel printing system which aims to improve print resolution by incorporating an additional immiscible carrier solvent into the ink delivery system. The resolution is improved due to the solvent-solvent interactions between the ink and the carrier solvent which alter the contact angle of the ink on the substrate and limit the printed feature size. We demonstrate the proof of concept of solvodynamic printing by printing silver nanoparticle inks on a polyethylene naphthalate substrate. Silver nanoparticle tracks with widths of 35.2 ± 7.0 μm were achieved using a 300 μm nozzle. This is equivalent to 11.7 ± 2.3% of the nozzle diameter. The result shows great potential in solvodynamic printing as not many modern printing techniques can achieve such nozzle to feature size ratios.

[Application of closed negative pressure irrigation and suction device in the treatment of high perianal abscess]

Objective: To explore the efficacy of closed negative pressure irrigation and suction device (Patent number: Z200780013509.8) in the treatment of high perianal abscess. Methods: From January 2015 to December 2016, ≥18-year-old patients with primary high perianal abscess who were treated at our department were prospectively enrolled. Exclusion criteria: (1) recurrent perianal abscess; (2) complicated with anal fistula formation; (3) preoperative, intraoperative or postoperative physical therapy, and curettage treatment, negative pressure irrigation; (4) Crohn's disease-related perianal abscess; (5) with immunosuppressive status, such as transplant recipients; (6) co-existence of malignant tumors, such as leukemia; (7) with diabetes; (8) those who could not receive long-term follow-up and were not suitable to participate in this study. According to the random number table method, the patients were randomly divided into negative pressure irrigation and suction group and routine drainage group. All patients were clearly diagnosed and the location and size of the perianal abscess were marked before surgery. These two groups were treated as follows: (1) Negative pressure irrigation and suction group: the skin was incised at a diameter of 1-2 cm at the site where the abscess fluctuated most obviously. After the abscess was removed, a closed negative pressure irrigation and suction device was installed and the pressure of -200 to -100 mmHg (1 mmHg=0.133 kPa) was maintained to keep the abscess cavity collapsed. Generally, the irrigation was stopped 5 days later or when the drainage was clear. The closed vacuum suction was maintained for 2 additional days, before the wound was sutured. (2) Conventional drainage group: conventional incision and drainage was carried out. The skin was cut at a diameter of 8 to 10 cm at the site of abscess with most obvious fluctuation. After the abscess was removed, normal saline gauze was used for dressing. Dressing was changed regularly until the wound healed. The efficacy, operative time, intraoperative bleeding, incision length, frequency of dressing change, pain index (visual analogue score, VAS score), postoperative healing time, complications, recurrence rate of perianal abscess, anal fistula formation rate were observed. The t test and χ² test were used for comparison between the 2 groups. Results: There were both 40 patients in the negative pressure irrigation and suction group and the conventional drainage group. There were 28 males and 12 females in negative pressure irrigation and suction group with a mean age of (38.3±12.0) years and mean disease course of (6.6±2.1) days. The abscess in pelvic-rectal space accounted for 50.0% (20/40) and the mean diameter of abscess was (8.0±3.7) cm. There were 26 males and 14 females in the conventional drainage group with a mean age of (37.1±11.8) years and mean disease course of (6.4±2.5) days. The abscess in pelvic-rectal space accounted for 55.0% (22/40) and the diameter of abscess was (8.2±3.5) cm. The differences in baseline data between two groups were not statistically significant (all P>0.05). Both groups successfully completed the operation. There was no significant difference in operative time between two groups (P>0.05). As compared to conventional drainage group, intraoperative blood loss in negative pressure irrigation and suction group was less [(12.1±5.5) ml vs. (18.3±4.4) ml, t=5.606, P<0.001], incision length was shorter [(2.3±0.8) cm vs. (7.6±1.7) cm, t=17.741, P<0.001], postoperative VAS pain scores at 1-, 3-, 7-, and 14-day after operation were lower [3.7±1.4 vs. 7.6±1.8, t=10.816, P<0.001; 3.0±1.3 vs. 6.8±1.6, t=11.657, P<0.001; 2.7±0.9 vs. 5.1±1.1, t=10.679, P<0.001; 1.2±0.3 vs. 1.6±0.4, t=5.060, P=0.019], the dressing change within 7 days after operation was less (3.5±1.2 vs. 12.6±2.7, t=19.478, P<0.001), postoperative healing time was shorter [(10.4±3.0) d vs. (13.5±3.8) d, t=4.049, P<0.001] and postoperative complication rate was lower [17.5% (7/40) vs. 2.5% (1/40), χ²=5.000, P=0.025]. During follow-up of 12 to 36 (24±5) months, the recurrence rate of perianal abscess within 1 year after operation and anal fistula formation rate in negative pressure irrigation and suction group were lower than those in conventional drainage group [5.0% (2/40) vs. 20.0% (8/40), χ²=4.114, P=0.042 and 2.5% (1/40) vs. 17.5% (7/40), χ²=5.000, P=0.025, respectirely]. The one-time cure rate of negative pressure irrigation and suction group and conventional drainage group was 92.5% (37/40) and 62.5%(25/40), respectirely (χ²=10.323, P=0.001). Conclusions: The application of the negative pressure irrigation and suction device in the treatment of high perianal abscess can improve the efficiency of one-time cure, reduce postoperative pain, accelerate healing time, decrease the morbidity of postoperative complication and the rates of abscess recurrence and anal fistula formation, indicating an improvement of the treatment.

[Suture under tension across cartilage in the application of the crooked nose surgery]

Objective:Observing the effect of maintain tension across suture between cartilages to fix new nasal structure on balance the asymmetric strength of the two sides of the cartilage and the recurrence of the postoperative crooked nose.Method:A L-shaped struct made of the nasal septum cartilage were fixed to maintain tension across structure between cartilage during rhinoplasty in 39 patients with crooked nasal deformity. Of 21 cases were type I deviation, of 12 cases were C-shaped deviation,and of 6 cases were S-shaped deviation.Result:A 1-5 years follow-up were performed. The effects were divided into three degrees: 30 cases excellent (76.92%), 6 cases good (15.38%) and 3 cases acceptable (7.69%).The rate of excellent and good was 92.31%(36/39). The type I improvement rate was 80.3%,the rate of type C was 83.6% and the improvement rate of type S was 84.1%,the overall improvement rate was about 81.9%.Conclusion:Suture under tension across cartilage can fix reconstruction of nasal structure effectively,improve the postoperative effect, reduce recurrence of crooked nose. The operation is simple and is an essential part of the nasal deformity correction technique.

[Detection the mutated protein aggregation and mitochondrial function in fibroblasts from amyotrophic lateral sclerosis patients with SOD1 gene mutations]

OBJECTIVES

To explore mutant superoxide dismutase (SOD)1 protein expression and mitochondrial function in amyotrophic lateral sclerosis (ALS) patients' fibroblasts carrying different SOD1 mutations.

METHODS

SOD1 gene mutation was detected using PCR and direct sequencing. Skin fibroblasts of three familial ALS patients with mutations and age/gender matched controls obtained by a punch skin biopsy were cultured. We performed immunofluorescence staining and quantitative detection of SOD1 proteins and mitochondrial membrane potential. Also, we detected the intracellular ROS by flow cytometry.

RESULTS

We found that fibroblasts from familial ALS patients carried SOD1-V14M, SOD1-G16A, SOD1-C111Y mutation, respectively. The cytoplasm abnormal SOD1 protein aggregates appeared in ALS patients carrying SOD1 mutations. And the cytoplasmic/nuclear ratio of SOD1 aggregates increased 2.54, 2.80, 3.25-fold for each mutations, respectively, compared to the control group. Three SOD1 mutant groups showed loss of mitochondrial membrane potential and the ratio of red / green fluorescence intensity decreased by 36%, 124%, 142%, respectively, compared to the control group. The intracellular ROS levels also increased 3.33, 3.65, and 6.87-fold respectively.

CONCLUSIONS

This work highlights that ALS alters SOD1 protein expression, mitochondrial function, and increases the ROS level even in peripheral tissues outside the central nervous system. Fibroblasts might therefore represent a powerful and minimally invasive tool to investigate ALS pathogenic mechanisms, which might translate into considerable advances in clinical management of the disease.

Students' Motivational Profiles in the Physical Education Context

The purpose of the current study is to test the self-determination theory (SDT) continuum hypothesis of motivation using latent profile analysis (LPA). A total of 3,220 school students took part in the study. We compared LPA solutions estimated using the four motivation types versus the two higher-order dimensions to assess their degree of correspondence to the SDT continuum hypothesis. To examine the concurrent validity of the profiles, we also verified their associations with three predictors (age, gender, perception of physical education teachers' autonomy-supportive behaviors) and two outcomes variables (perceived competence and intentions to be physically active). The results showed that profiling using the four motivation types provides more differentiated and meaningful description of responses to the Perceived Locus of Causality Scale, compared with profiling using two higher-order factors. In general, the results of the current study were consistent with the SDT continuum hypothesis of human motivation.

Gentamicin-loaded strontium-containing hydroxyapatite bioactive bone cement--an efficient bioactive antibiotic drug delivery system

Modified strontium-containing hydroxyapatite (Sr-HA) bone cement was loaded with gentamicin sulfate to generate an efficient bioactive antibiotic drug delivery system for treatment of bone defects. Gentamicin release and its antibacterial property were determined by fluorometric method and inhibition of Staphylococcus aureus (S. aureus) growth. Gentamicin was released from Sr-HA bone cement during the entire period of study and reached around 38% (w/w) cumulatively after 30 days. Antibacterial activity of the gentamicin loaded in the cements is clearly confirmed by the growth inhibition of S. aureus. The results of the amount and duration of gentamicin release suggest a better drug delivery efficiency in Sr-HA bone cement over polymethylmethacrylate bone cement. Bioactivity of the gentamicin-loaded Sr-HA bone cement was confirmed with the formation of apatite layer with 1.836 ± 0.037 μm thick on day 1 and 5.177 ± 1.355 μm thick on day 7 after immersion in simulated body fluid. Compressive strengths of the gentamicin-loaded Sr-HA cement reached 132.60 ± 10.08 MPa, with a slight decrease from the unloaded groups by 4-9%. Bending moduli of Sr-HA cements with and without gentamicin were 1.782 ± 0.072 GPa and 1.681 ± 0.208 GPa, respectively. On the contrary, unloaded Sr-HA cement obtained slightly larger bending strength of 35.48 ± 2.63 MPa comparing with 33.00 ± 1.65 MPa for loaded cement. No statistical difference was found on the bending strengths and modulus of gentamicin-loaded and -unloaded Sr-HA cements. Sr-HA bone cement loaded with gentamicin was proven to be an efficient drug delivery system with uncompromised mechanical properties and bioactivity.

A longitudinal study of students' academic self-concept in a streamed setting: The Singapore context

BACKGROUND

Although several studies support the existence of a negative stream effect on lower-ability stream students' academic self-concept, there is not enough longitudinal research evidence to preclude the possibility that the stream effect may only be temporary. In addition, not much is known about the effect of streaming on changes in students' academic self-concept over time.

AIMS

The main aims of the study were to examine the effect of streaming on (a) the students' academic self-concept immediately after the streaming process, and at yearly intervals for 3 consecutive years, and (b) the changes in students' academic self-concept over a 3 year period.

SAMPLE

The sample comprised 495 Secondary 1 students (approximate age 13) from three government coeducational schools in Singapore.

METHOD

A longitudinal survey using a self-reported questionnaire.

RESULTS

Results showed that the lower-ability stream students had a more negative academic self-concept than the higher-ability stream students immediately after streaming, but they had a more positive academic self-concept 3 years after being streamed. In addition, it was established that the students' academic self-concept declined from Secondary 1 to Secondary 3. Nonetheless, the decline was more pronounced for the higher-ability stream students than the lower-ability stream students.

CONCLUSIONS

Streaming may have a short-term negative impact on lower-ability stream students' academic self-concept. However, in the long run, being in the lower-ability stream may not be detrimental to their academic self-concept.

An Investigation of Working Memory Rehearsal in Multiple Sclerosis Using fMRI

The present study examined patterns of cerebral activation during a working memory (WM) rehearsal task in individuals diagnosed with multiple sclerosis (MS) and in healthy adults. BOLD functional magnetic resonance imaging (fMRI) was performed using a 1.5 T GE scanner to assess activation during a WM task adapted from the Sternberg paradigm (Sternberg, 1969). Participants included 8 individuals diagnosed with MS, and 5 healthy controls (HCs) matched for age and education. Task difficulty was manipulated by increasing the length of time that strings of letters were to be rehearsed. Findings revealed increased right prefrontal cortex activation and increased right temporal lobe activation in individuals diagnosed with MS compared to HCs. The potential explanations for increased right hemisphere activation in persons with MS are discussed.

Influence of perceived motivational climate on achievement goals in physical education: a structural equation mixture modeling analysis

The purpose of the current study was to examine the influence of perceived motivational climate on achievement goals in physical education using a structural equation mixture modeling (SEMM) analysis. Within one analysis, we identified groups of students with homogenous profiles in perceptions of motivational climate and examined the relationships between motivational climate, 2 x 2 achievement goals, and affect, concurrently. The findings of the current study showed that there were at least two distinct groups of students with differing perceptions of motivational climate: one group of students had much higher perceptions in both climates compared with the other group. Regardless of their grouping, the relationships between motivational climate, achievement goals, and enjoyment seemed to be invariant. Mastery climate predicted the adoption of mastery-approach and mastery-avoidance goals; performance climate was related to performance-approach and performance-avoidance goals. Mastery-approach goal had a strong positive effect while performance-avoidance had a small negative effect on enjoyment. Overall, it was concluded that only perception of a mastery motivational climate in physical education may foster intrinsic interest in physical education through adoption of mastery-approach goals.

Examining lactate in severe TBI using proton magnetic resonance spectroscopy

PRIMARY OBJECTIVE

Clinical management of acute traumatic brain injury (TBI) has emphasized identification of secondary mechanisms of pathophysiology. An important objective in this study is to use proton magnetic resonance spectroscopy (pMRS) to examine early metabolic disturbance due to TBI.

RESEARCH DESIGN

The current design is a case study with repeated measures.

METHOD AND PROCEDURE

Proton magnetic resonance imaging was used to examine neurometabolism in this case of very severe brain trauma at 9 and 23 days post-injury. MRI was performed on a clinical 1.5 Tesla scanner.

MAIN OUTCOMES AND RESULTS

These data also reveal that pMRS methods can detect lactate elevations in an adult surviving severe head trauma and are sensitive to changes in basic neurometabolism during the first month of recovery.

CONCLUSIONS

The current case study demonstrates the sensitivity of pMRS in detecting metabolic alterations during the acute recovery period. The case study reveals that lactate elevations may be apparent for weeks after severe neurotrauma. Further work in this area should endeavour to determine the ideal time periods for pMRS examination in severe TBI as well as the ideal locations of data acquisition (e.g. adjacent or distal to lesion sites).

Linking watershed and eutrophication modelling for the Shihmen Reservoir, Taiwan

The Shihmen Reservoir, located in northern Taiwan, features the second storage volume of impoundments on the island. The watershed of the Shihmen Reservoir has been subjected to serious pollutants due to anthropogenic interference. This study applies a watershed model, BASINS, to simulate the flow and nutrients loads from the watershed. BASINS then drives the CE-QUAL-W2 model for water quality predictions in the reservoir. The watershed modelling results are compared with field data. They reveal that significant nutrient loads were generated from the watershed during storms. The model calibration and verification were achieved with water surface elevation, temperature, and water quality constituents including nutrients, dissolved oxygen, and chlorophyll a in the reservoir using the eutrophication model.

Modelling the epidemiology of Verocytotoxin-producing Escherichia coli serogroups in young calves

We investigate the epidemiology of 12 Verocytotoxin-producing Escherichia coli (VTEC) serogroups observed in a calf cohort on a Scottish beef farm. Fitting mathematical models to the observed time-course of infections reveals that there is significant calf-to-calf transmission of VTEC. Our models suggest that 40% of all detected infections are from calf-to-calf transmission and 60% from other sources. Variation in the rates at which infected animals recover from infection by different VTEC serogroups appears to be important. Two thirds of the observed VTEC serogroups are lost from infected calves within 1 day of infection, while the rest persist for more than 3 days. Our study has demonstrated that VTEC are transmissible between calves and are typically lost from infected animals in less than 1 week. We suggest that future field studies may wish to adopt a tighter sampling frame in order to detect all circulating VTEC serogroups in similar animal populations.

Critical review on non-operative management of adolescent idiopathic scoliosis

There are a number of different non-operative interventions which aim to control moderate adolescent idiopathic scoliosis (AIS) from progression. Clinicians may find difficulties in the selection of appropriate interventions for AIS. A comprehensive literature review was carried out to study all contemporary non-operative interventions, it was noted that rigid spinal orthoses apparently give more curve control; however, it would compromise the patient's quality of life via those inevitable factors--physical constraint, poor acceptance and psychological disturbance. There is a trend to develop more effective, acceptable and user-friendly interventions. Under such an aspiration, the theories and clinical evidence of different interventions should be developed along the clinical pathway of early intervention with reliable indicators/predictors, patient's active participation, dynamic control mechanism, holistic psychological and psychosocial considerations, and effective and long-lasting outcome.

Therapeutic effect of pirenzepine for clozapine-induced hypersalivation: a randomized, double-blind, placebo-controlled, cross-over study

The objective of this study was to investigate the efficacy of pirenzepine in the treatment of clozapine-induced hypersalivation. Pirenzepine is reported to counteract hypersalivation by its selective antagonistic activity on the M4-muscarinic receptor, which is stimulated by clozapine. Twenty patients with clozapine-induced hypersalivation underwent a random-order, double-blind, placebo-controlled, cross-over trial which lasted 8 weeks each for the pirenzepine and placebo investigations, with a 4-week washout period in between. The severity of hypersalivation was assessed using an objective measure: saliva production monitored through the diameter of wetted surface on tissue paper placed over the patient's pillow. Our study showed that pirenzepine had no significant therapeutic effect on hypersalivation compared with placebo, suggesting that hypersalivation induced by clozapine might have a neurobiological basis other than the M4-muscarinic receptor.

Detection of circulating CEA molecules in human sera and leukopheresis of peripheral blood stem cells with E. coli expressed bispecific CEAScFv-streptavidin fusion protein-based immuno-PCR technique

In this study, a method called bispecific CEAScFv-streptavidin fusion protein-based immuno-PCR technique will be tested experimentally. The application of the bispecific fusion protein-based immuno-PCR technique has the significant advantage that it can be readily applied in the clinical setting, as well as tested as a potential screening tool in high-risk populations of certain types of cancer.

Functional magnetic resonance imaging of working memory impairment after traumatic brain injury

OBJECTIVES

To examine patterns of brain activation while performing a working memory task in persons with moderate to severe traumatic brain injury (TBI) and healthy controls. It is well established that working memory is an area of cognition that is especially vulnerable to disruption after TBI. Although much has been learned about the system of cerebral representation of working memory in healthy people, little is known about how this system is disrupted by TBI.

METHODS

Functional magnetic resonance imaging (fMRI) was used to assess brain activation during a working memory task (a modified version of the paced auditory serial addition test) in nine patients with TBI and seven healthy controls.

RESULTS

Patients with TBI were able to perform the task, but made significantly more errors than healthy controls. Cerebral activation in both groups was found in similar regions of the frontal, parietal, and temporal lobes, and resembled patterns of activation found in previous neuroimaging studies of working memory in healthy persons. However, compared with the healthy controls, the TBI group displayed a pattern of cerebral activation that was more regionally dispersed and more lateralised to the right hemisphere. Differences in lateralisation were particularly evident in the frontal lobes.

CONCLUSIONS

Impairment of working memory in TBI seems to be associated with alterations in functional cerebral activity.

Serotonin 6 receptor polymorphism in schizophrenia: frequency, age at onset and cognitive function

The relative abundance of serotonin 6 receptor (5HT6) in some limbic regions and the high affinity of some antipsychotics for 5HT6 suggest that the 5HT6 gene might play a role in the pathogenesis of schizophrenic disorders. A recent study reported an association between a C267T polymorphism of the 5HT6 gene and schizophrenia. In order to test whether the 5HT6 gene plays a role in the pathogenesis of schizophrenic disorders, patients (n = 148) and control subjects (n = 160) were genotyped for 5HT6. We also investigated the relationship between genotypes and patients' age at onset and cognitive function in schizophrenic patients. Cognitive function in the patients was evaluated by the Mini-Mental State Examination (MMSE). The results demonstrated no significant differences in genotype or allele frequencies between controls and patients. In the patient group, age at onset and MMSE score did not differ significantly among the three 5HT6 genotpyes. The results of this study suggest that the 5HT6 C267T polymorphism plays no major role in susceptibility to the development of schizophrenia and is not related to cognitive impairment or age at onset in schizophrenic patients. Further studies of the relation between 5HT6 polymorphism and the symptoms and the therapeutic response in schizophrenic patients may help to elucidate the role of 5HT6 in the pathogenesis of schizophrenia.

A modeling study of water quality in main channel and estuarine wetland

A simple computation framework is applied to include estuarine wetland and their interaction with main channels in estuarine modeling. The concept and the model implementation of the scheme are explained using a vertical two-dimensional model of estuarine hydrodynamics and water quality. The model was applied to the Tanshui River estuary and Kuan-Du wetland. The model is calibrated and verified by the available measured data. Simulations are also conducted for various upstream freshwater discharges to predict water quality in the main channel and estuarine wetland. The results show that the inclusion of estuarine wetland in a water-quality model not only provides a framework for computing water-quality conditions but also accounts for the interaction between wetland and main channel. The model provides a useful tool for environmental planning, protection and proposed wetland restoration works.

Testosterone regulates alpha-synuclein mRNA in the avian song system

Alpha-synuclein is a small, highly conserved protein in vertebrates that has been linked to several neurodegenerative diseases. The avian song control system is one of the model systems in which the protein was independently discovered. Alpha-synuclein is dynamically regulated in the song system during song learning, a process in which sex steroids play a central role. We compared alpha-synuclein mRNA expression in the brains of 12 adult male chipping sparrows (Spizella passerina) treated with either testosterone or blank s.c. implants. We saw pronounced upregulation of alpha-synuclein mRNA in, as well as an increase in the volume of, the song control nucleus area X in response to exogenous testosterone. To our knowledge this is the first report of steroid regulation of synuclein gene expression in any model system.

Different mechanisms of radiation-induced loss of heterozygosity in two human lymphoid cell lines from a single donor

Allelic loss is an important mutational mechanism in human carcinogenesis. Loss of heterozygosity (LOH) at an autosomal locus is one outcome of the repair of DNA double-strand breaks (DSBs) and can occur by deletion or by mitotic recombination. We report that mitotic recombination between homologous chromosomes occurred in human lymphoid cells exposed to densely ionizing radiation. We used cells derived from the same donor that express either normal TP53 (TK6 cells) or homozygous mutant TP53 (WTK1 cells) to assess the influence of TP53 on radiation-induced mutagenesis. Expression of mutant TP53 (Met 237 Ile) was associated with a small increase in mutation frequencies at the hemizygous HPRT (hypoxanthine phosphoribosyl transferase) locus, but the mutation spectra were unaffected at this locus. In contrast, WTK1 cells (mutant TP53) were 30-fold more susceptible than TK6 cells (wild-type TP53) to radiation-induced mutagenesis at the TK1 (thymidine kinase) locus. Gene dosage analysis combined with microsatellite marker analysis showed that the increase in TK1 mutagenesis in WTK1 cells could be attributed, in part, to mitotic recombination. The microsatellite marker analysis over a 64-cM region on chromosome 17q indicated that the recombinational events could initiate at different positions between the TK1 locus and the centromere. Virtually all of the recombinational LOH events extended beyond the TK1 locus to the most telomeric marker. In general, longer LOH tracts were observed in mutants from WTK1 cells than in mutants from TK6 cells. Taken together, the results demonstrate that the incidence of radi-ation-induced mutations is dependent on the genetic background of the cell at risk, on the locus examined, and on the mechanisms for mutation available at the locus of interest.

The effect of brain tumors on BOLD functional MR imaging activation in the adjacent motor cortex: implications for image-guided neurosurgery

BACKGROUND AND PURPOSE

Functional MR (fMR) imaging data coregistered to a neurosurgical navigation system have been proposed as guides for the resection of brain tumor in or adjacent to eloquent cortices. The purpose of this study was to compare data obtained from the side of the brain affected by tumor with the contralateral side and to determine if there are physiological limitations of fMR imaging in accurately determining the location of the primary motor cortex.

METHODS

Ten patients with tumors in or directly adjacent to the motor cortex were studied with fMR imaging (finger-tapping paradigm). fMR imaging data were analyzed using multiple R values. These data were coregistered to a real-time intraoperative neurosurgical navigation system.

RESULTS

Significant variability of motor cortex activation patterns was noted among individual patients. The activation volumes on the side of the tumor were significantly smaller compared with the contralateral side for all tumors not previously resected (0.66+/-0.47). This was most pronounced in glioblastomas (0.27+/-0.21). We propose that these differences were caused by a loss of autoregulation in the tumor vasculature of glioblastomas and venous effects.

CONCLUSION

Notwithstanding the differences noted, the motor cortex was identified successfully in all patients. This was confirmed by intraoperative physiological identification of the motor cortex and a lack of postoperative neurologic deficit.

Identification of the corticospinal tracts achieved using blood-oxygen-level-dependent and diffusion functional MR imaging in patients with brain tumors

Diffusion-weighted MR imaging was used to delineate the corticospinal tract (CST) successfully and to depict its relationship to adjacent brain tumors. The CST was defined by a method by which it seems possible to delimit the distance from the CST to the main tumor mass and to show displacement and infiltration of the tract by the neoplasia. This information cannot be gathered from routine anatomic MR imaging.

Design and optimization of a diode-pumped fiber-coupled yb:er glass waveguide laser

An adaptive simulated annealing optimization algorithm is used to derive laser rate equation and waveguiding models with which the best design for a diode-pumped fiber-coupled, Yb:Er glass waveguide laser can be determined. Material parameters that correspond to commercially available laser-glass and diode-pump sources are used in this study. Given a continuous-wave 300-mW pump at 977 nm, approximately 48 mW of power at 1540 nm can be coupled into the LP(01) mode of an optical fiber. Fabrication and alignment tolerance analyses are presented.

Functional magnetic resonance imaging and radiosurgical dose planning

OBJECTIVE

To assess the effect of functional magnetic resonance imaging (fMRI) on stereotactic radiosurgical (SRS) dose planning.

METHODS

Patients included those undergoing SRS whose lesions were in or near areas that could be identified with fMRI. After processing, an fMR scan was registered to the anatomic scan, and this dataset was registered to a stereotactic CT scan. The imaged functional areas were contoured along with standard anatomical targets. Dose planning was done at first with the functional volumes rendered invisible; the plans were then adjusted as needed using the functional targets. Doses were measured using a dose-volume histogram tool.

RESULTS

SRS was performed in 12 patients, 1 of whom also underwent SRT. Functional volumes studied included motor cortex in 8 patients, visual in 6 and language in 3; a total of 33 functional targets were imaged. Prescription doses ranged from 12 to 22.5 Gy (mean 19.5 Gy), and the maximum dose to functional volumes from 8 cGy to 18.5 Gy (mean 2.9 Gy). In 6 patients, arc adjustment using functional targets yielded a >50% reduction in dose to at least one functional volume; in all patients, the dose reduction to 50 and 75% of functional volumes averaged 4% (12 cGy) and 13% (30 cGy), respectively, while the reduction of maximal dose averaged 24% (50 cGy).

CONCLUSIONS

fMRI can be used in SRS to reduce irradiation of eloquent brain using standard prescription doses. Appropriate arc adjustment may allow for escalation of the dose to the targeted lesion.

Functional magnetic resonance image-guided surgery of tumors in or near the primary visual cortex

OBJECTIVE

To assess the accuracy of functional magnetic resonance imaging (fMRI) of the primary visual cortex in patients undergoing surgery for tumors in the occipital lobe.

METHODS

Two patients with nondominant occipital lobe tumors were studied, one with a solitary lung metastasis and another with radiation necrosis after radiosurgery for a low-grade astrocytoma. At surgery, visual evoked potentials (VEPs) were stimulated using Light-emitting-diode goggles and recorded using cortical grids placed immediately after brain exposure. The location of the peak VEP was compared to that predicted by the registered functional scan.

RESULTS

In each case, the epicenter of visual activation as represented on the registered fMRI corresponded to the site of peak VEP recording. Prediction error for the visual cortex, measured in patient 1, was 1.0 mm. Visual confirmation showed the registration in the second patient to be accurate as well.

CONCLUSION

As previously demonstrated for sensorimotor fMRI, visual fMRI accurately predicts the location of the primary visual cortex. Additional confirmation is expected with more clinical experience.

The effect of brain tumors on BOLD functional MR imaging activation in the adjacent motor cortex: implications for image-guided neurosurgery

BACKGROUND AND PURPOSE

Functional MR (fMR) imaging data coregistered to a neurosurgical navigation system have been proposed as guides for the resection of brain tumor in or adjacent to eloquent cortices. The purpose of this study was to compare data obtained from the side of the brain affected by tumor with the contralateral side and to determine if there are physiological limitations of fMR imaging in accurately determining the location of the primary motor cortex.

METHODS

Ten patients with tumors in or directly adjacent to the motor cortex were studied with fMR imaging (finger-tapping paradigm). fMR imaging data were analyzed using multiple R values. These data were coregistered to a real-time intraoperative neurosurgical navigation system.

RESULTS

Significant variability of motor cortex activation patterns was noted among individual patients. The activation volumes on the side of the tumor were significantly smaller compared with the contralateral side for all tumors not previously resected (0.66+/-0.47). This was most pronounced in glioblastomas (0.27+/-0.21). We propose that these differences were caused by a loss of autoregulation in the tumor vasculature of glioblastomas and venous effects.

CONCLUSION

Notwithstanding the differences noted, the motor cortex was identified successfully in all patients. This was confirmed by intraoperative physiological identification of the motor cortex and a lack of postoperative neurologic deficit.

Directional correlation in direct and sequential double ionization of model atoms

We discuss directional dependence in the time development of spatial wavefunctions, which includes jet formation, for two-electron model atoms exposed to intense laser fields. Two competing scenarios for double ionization are evident: (1) both electrons emerge simultaneously from the core region and on the same side of the nucleus, and (2) the electrons detach on opposite sides but not simultaneously. The importance of the electron-electron repulsion contribution to the competing processes is investigated for various laser intensities.

Functional magnetic resonance imaging aided radiation treatment planning

Functional MRI (magnetic resonance imaging) allows one to noninvasively identify various eloquent cortices in the brain. The integration of cortical activation information into radiosurgical treatment planning may provide an alternative to prevent or minimize radiation damage to eloquent cortex. A novel approach of directly integrating the fMRI (functional magnetic resonance imaging) brain map into treatment planning is proposed. Three brain tumor patients have been studied using this method with motor and/or visual paradigms. Brain activation was demonstrated in eloquent cortex at the precentral gyrus (motor area) and medial occipital lobe (visual area). The activation maps were transferred to a treatment planning workstation, (XKnife), and 3D (three-dimensional) activation maps were generated and co-registered to a 3D CT (computed tomography) anatomical data set, which provided the calibration localizer, for treatment planning. Radiosurgery was designed based on both functional and structural information by the medical team consisting of a radiation oncologist, a neurosurgeon and a physicist. The average maximum dose for the tumor was 2113 cGy. The average maximum dose for tissue surrounding the tumor was 1600 cGy. The average dose with fMRI information to the eloquent cortex was 163.4 cGy over three patients, while without fMRI information it was 240.5 cGy. The average percentage dose reduction over three patients is 32%. The results suggest that using this method can reduce the dose to the eloquent cortex. This approach provides the physician with additional information for treatment planning and may spare the patient unnecessary radiation exposure to adjacent eloquent cortices.