Spin-Momentum Locking and Ultrafast Spin-Charge Conversion in Ultrathin Epitaxial Bi1 - x Sbx Topological Insulator.

The helicity of three-dimensional (3D) topological insulator surface states has drawn significant attention in spintronics owing to spin-momentum locking where the carriers' spin is oriented perpendicular to their momentum. This property can provide an efficient method to convert charge currents into spin currents, and vice-versa, through the Rashba-Edelstein effect. However, experimental signatures of these surface states to the spin-charge conversion are extremely difficult to disentangle from bulk state contributions. Here, spin- and angle-resolved photo-emission spectroscopy, and time-resolved THz emission spectroscopy are combined to categorically demonstrate that spin-charge conversion arises mainly from the surface state in Bi1 - x Sbx ultrathin films, down to few nanometers where confinement effects emerge. This large conversion efficiency is correlated, typically at the level of the bulk spin Hall effect from heavy metals, to the complex Fermi surface obtained from theoretical calculations of the inverse Rashba-Edelstein response. Both surface state robustness and sizeable conversion efficiency in epitaxial Bi1 - x Sbx thin films bring new perspectives for ultra-low power magnetic random-access memories and broadband THz generation.

[Liuwei Dihuang Pills alleviates postmenopausal osteoporosis and fatigue in rats by inhibiting the epigenetic regulatory molecule BRD4 pathway].

OBJECTIVE: To explore the role of epigenetic signal molecule bromodomain protein 4 (BRD4) in mediating the therapeutic effect of Liuwei Dihuang (LWDH) Pills on postmenopausal osteoporosis (PMOP) and fatigue. METHODS: Thirty rat models of PMOP induced by bilateral ovariectomy were randomized equally into two groups for treatment with normal saline (model group) or LWDH Pills (385.7 mg/kg), with another 15 sham-operated rats as the sham operation group. After 12 weeks of treatment, femoral samples were taken to determine the bone density and BRD4 protein expression. The weight-bearing exhaustive swimming time of the rat models was recorded, and serum levels of cyclic adenosine monophosphate (cAMP) and cyclic guanosine monophosphate (cGMP) were measured using enzyme-linked immunosorbent assay. In cultured primary osteoblasts the changes in the expressions of BRD4, MAPK and NF-κB proteins were detected by immunofluorescence staining following treatment with LWDH Pills. RESULTS: The rat models of PMOP showed significantly up-regulated expression of BRD4 protein in the femoral tissue (P < 0.05), which was obviously lowered by treatment with LWDH Pills. The rats treated with LWDH Pills also showed significant improvement of fatigue. Immunofluorescent staining of the osteoblasts showed that treatment with LWDH Pills significantly decreased the protein expressions of BRD4, MAPK and NF-κB. Analysis of the GSE56116 dataset revealed that that patients with kidney-yin deficiency had significantly higher BRD4 expression than those in the kidney-yang-deficiency group and non-kidney-deficiency group (P < 0.05). The upregulation of BRD4 expression involved multiple signaling pathways including neural ligand receptor response, cytoskeleton rearrangement, cytokine interaction, and granulocyte colony-stimulating factor chemotaxis pathways. CONCLUSION: LWDH can alleviate PMOP and fatigue by decreasing BRD4 signaling pathway, suggesting that potential of BRD4 as a promising therapeutic target for PMOP.

[Improving the management of chronic Pseudomonas aeruginosa infection in lower respiratory tract].

Pseudomonas aeruginosa is one of the most important pathogens causing chronic lower respiratory tract infections in patients with chronic lung diseases such as cystic fibrosis, bronchiectasis and chronic obstructive pulmonary disease. The poor prognosis of these diseases has been found to be associated with chronic Pseudomonas aeruginosa infection in lower respiratory tract, which can be a consequence or a cause of the disease progression depending on different circumstances. Optimizing the management of chronic Pseudomonas aeruginosa infection is of great significance to improve the prognosis of these chronic lung diseases. Unlike the therapy of acute pneumonia due to Pseudomonas aeruginosa, the goals of the management for chronic Pseudomonas aeruginosa infection are not only to control infection, but also to reduce symptoms, prevent exacerbations, stop the disease progression and improve the quality of life. In addition to systemic anti-pseudomonas therapy during exacerbations, long-term multiple measures including anti-inflammatory therapy, immunomodulatory therapy,airway clearance techniques, mucoactive therapy, etc. should also be given to the patients with chronic lower respiratory tract infection due to Pseudomonas aeruginosa.

[Construction of a risk assessment indicator system for re-establishment of imported malaria].

OBJECTIVE: To create a risk assessment indicator system for re-establishment of imported malaria. METHODS: The risk assessment indicator system for re-establishment of imported malaria was preliminarily constructed through literature review and thematic discussions. A total of 26 malaria control experts were selected to carry out a two-round Delphi consultation of the indicator system. The active coefficient, authority coefficient and coordination coefficient of the experts and the coefficient of variation on each indicator were calculated for indicator screening and the weight of each indicator was calculated. The reliability of the indicator system was evaluated using Cronbach's coefficient α, and the content validity of the indicator system was evaluated using the authority coefficient of the expert, while the structural validity of the indicator system was evaluated using Kaiser-Meyer-Olkin (KMO) test and factor analysis. RESULTS: Two rounds of Delphi expert consultations were completed by 23 malaria control experts, and a risk assessment indicator system for re-establishment of imported malaria was constructed, including 3 primary indicators, 7 secondary indicators, and 21 tertiary indicators. The active coefficient (100.00% vs. 88.46%; P < 0.01) and coordination coefficient of the expert (0.372 vs. 0.286; P < 0.01) were significantly greater in the second round of the Delphi expert consultation than in the first round. After the second round of the Delphi expert consultation, the authority coefficient of the experts ranged from 0.757 to 0.930 on each indicator, and the coefficients of variation were 0.098 to 0.136, 0.112 to 0.276 and 0.139 to 0.335 for the primary, secondary and tertiary indicators, respectively. The overall Cronbach's coefficient α of the indicator system was 0.941, and there were significant differences in the KMO values for primary (KMO value = 0.523; χ2 = 18.192, P < 0.05), secondary (KMO value = 0.694, χ2 = 51.499, P < 0.01) and tertiary indicators (KMO value = 0.519; χ2 = 477.638, P < 0.01), while the cumulative contribution rate of six principal components in the tertiary indicators was 84.23%. The normalized weights of three primary indicators of the source of infection, transmission condition and control capability were 0.337, 0.333 and 0.329, and the three secondary indicators with the greatest normalized weights included the number of imported cases and malaria parasite species (0.160), introduction of imported cases in China and medical care seeking (0.152), vector species and density (0.152), while the five tertiary indicators with the greatest normalized weights included the malaria parasite species of imported cases (0.065), vector populations (0.064), and the time interval from onset to medical care seeking (0.059), number of imported cases (0.056), and the time interval from medical care seeking to definitive diagnosis (0.055). CONCLUSIONS: A risk assessment indicator system for re-establishment of imported malaria is successfully created, which provides insights into the assessment of the risk of re-establishment of imported malaria and management of key high-risk factors in malaria-eliminated areas.

Grading of Pediatric Intracranial Tumors: Are Intravoxel Incoherent Motion and Diffusional Kurtosis Imaging Superior to Conventional DWI?

BACKGROUND AND PURPOSE: An accurate evaluation of the World Health Organization grade is critical in pediatric intracranial tumors. Our aim was to explore the correlations between parameters derived from conventional DWI, intravoxel incoherent motion, and diffusional kurtosis imaging with histopathologic features to evaluate the accuracy of diffusion parameters for grading of pediatric intracranial tumors. MATERIALS AND METHODS: Fifty-four pediatric patients with histologically proved intracranial tumors who underwent conventional DWI, intravoxel incoherent motion, and diffusional kurtosis imaging were recruited. The conventional DWI (ADC), intravoxel incoherent motion (pure diffusion coefficient [D], pseudodiffusion coefficient [D*], perfusion fraction [f], diffusional kurtosis imaging [K], and diffusion coefficient [Dk]) parameters in the solid component of tumors were measured. The cellularity, Ki-67, and microvessel density were measured. These parameters were compared between the low- and high-grade pediatric intracranial tumors using the Mann-Whitney U test. Spearman correlations and receiver operating characteristic analysis were performed. RESULTS: The ADC, D, and Dk values were lower, whereas the K value was higher in high-grade pediatric intracranial tumors than in low-grade tumors (all, P < .001). The K value showed positive correlations (r = 0.674-0.802; all, P < .05), while ADC, D, and Dk showed negative correlations with cellularity and Ki-67 (r = -0.548 to -0.740; all, P < .05). The areas under the curve of ADCVOI, DVOI, DkVOI, and KVOI were 0.901, 0.894, 0.863, and 0.885, respectively, for differentiating high- from low-grade pediatric intracranial tumors. The area under the curve difference in grading pediatric intracranial tumors was not significant (all, P > .05). CONCLUSIONS: Intravoxel incoherent motion- and diffusional kurtosis imaging-derived parameters have similar performance compared with conventional DWI in predicting pediatric intracranial tumor grade. The diffusion metrics may potentially reflect tumor cellularity and Ki-67 in pediatric intracranial tumors.

[A prospective multi-center clinical investigation of HIV-negative pulmonary cryptococcosis in China].

Objective: To investigate the current status of the diagnosis and treatment of pulmonary cryptococcosis in respiratory medicine and improve the understanding of the clinical characteristics of HIV-negative pulmonary cryptococcosis in China. Methods: A prospective multi-center open cohort study was designed to screen for pulmonary cryptococcosis in the general wards and intensive care units of the Department of Respiratory Diseases in 22 hospitals. The HIV-negative patients with positive cryptococcal etiological diagnosis based on smear culture, antigen detection and histopathology were enrolled in the study. The clinical data of enrolled patients were collected and analyzed. Results: A total of 457 cases of pulmonary cryptococcosis were enrolled, among which 3.28% (15/457) were disseminated infections. The case fatality rate was 0.88% (4/457). The majority of the cases were diagnosed by histopathological examinations (74.40%, 340/457) and cryptococcus antigen detection (37.64%, 172/457). Patients with pulmonary cryptococcosis accounted for 2.04‰ (457/223 748) of the total hospitalized patients in the Department of Respiratory Diseases during the same period, and the ratio was the highest in south and east China. Meanwhile, 70.24% (321/457) of the patients had no underlying diseases, while 87.75% (401/457) were found to have immunocompetent status. Cough and expectoration were the most common clinical symptoms in patients with pulmonary cryptococcosis. However, 25.16% (115/457) of the patients had no clinical symptom or physical signs. In terms of imaging features on pulmonary CT, multiple pulmonary lesions were more common than isolated lesions, and there were more subpleural lesions than perihilar or medial lesions. Morphologically, most of the lesions were middle-sized nodules (1-5 cm) or small-sized nodules (3 mm to 1 cm). The sensitivity of serum cryptococcus antigen test was 71.99% (203/282). Moreover, antigen-positive patients differed from antigen-negative patients in terms of basic immune status, clinical symptoms, imaging features and infection types. Meanwhile, immunocompromised patients differed from immunocompetent patients in terms of clinical symptoms, physical signs, infection-related inflammation indicator levels, imaging features, serum cryptococcus antigen positive rate and prognosis. Conclusions: The majority of cases of HIV-negative pulmonary cryptococcosis in China had no underlying disease or immunocompromised status, and the overrall prognosis was favorable. However, early diagnosis of HIV-negative pulmonary cryptococcosis remains challenging due to the complicated manifestations of the disease.

[Enterobius vermicularis infection in Guiyang City, Guizhou Province: a case report].

The report presents a case with Enterobius vermicularis infections in Guiyang City, Guizhou Province, aiming to strengthen the attention to parasitic infections.

[The application of next-generation sequencing in the diagnosis of Pneumocystis pneumonia in non-HIV infected patients].

Objective: To evaluate the clinical value of next-generation sequencing in the diagnosis of Pneumocystis pneumonia in non-HIV infected patients. Methods: A retrospective study was conducted on the diagnosis and treatment of Pneumocystis pneumonia in 5 non-HIV patients in the Fourth Medical Center of the General Hospital of the PLA from September 1, 2017 to September 1, 2018. Next-generation sequencing of BALF were compared with the traditional laboratory microbiological test, and the advantages of the next-generation sequencing in the diagnosis of Pneumocystis pneumonia in non-HIV infected patients were analyzed. Results: There were 3 males and 2 females, with a mean age (48±6) years. Three patients had membranous nephropathy, a patient had tuberculous meningitis, and a patient had esophageal cancer after radiotherapy and chemotherapy. All patients had glucocorticoid medication history before. The clinical manifestations were fever, cough and dyspnea. The chest CT mainly showed bilateral lung ground glass shadows. All the results of 1, 3-ß-D-glucan test were more than 1 000 ng/L. Bronchoalveolar lavage was performed in the 5 cases, and Pneumocystis cysts were found in 1 BALF by Gomori's methenamine silver nitrate staining, and the DNAs of Pneumocystis and human herpesvirus were detected in 5 BALFs by next-generation sequencing. All patients were treated with sulfamethoxazole/trimethoprim (orally, 1.44 g, q8 h) for 23 to 72 days (median 33 days), and with ganciclovir(Ⅳ, 250 mg q12 h) for 6 to 22 days (median 15 days). The chest CT manifestations and symptoms were improved after treatment, without death. Conclusions: The next-generation sequencing of BALF is more specific and sensitive in the diagnosis of Pneumocystis pneumoniae in non-HIV patients. It is faster, more comprehensive and more accurate than the traditional laboratory test, and could be widely used as a PCP diagnosis technique.

MR Imaging Features of Anaplastic Pleomorphic Xanthoastrocytoma Mimicking High-Grade Astrocytoma.

BACKGROUND AND PURPOSE: Anaplastic pleomorphic xanthoastrocytoma, which has been recently defined as a distinct entity in the 2016 World Health Organization classification, may exhibit aggressive clinical behavior and relatively worse prognosis than pleomorphic xanthoastrocytoma. This study aimed to investigate whether there were any differences in MR imaging characteristics between these 2 tumors. MATERIALS AND METHODS: This retrospective study included 9 patients with anaplastic pleomorphic xanthoastrocytoma and 10 patients with pleomorphic xanthoastrocytoma who underwent MR imaging before an operation. DWI was performed in 17 patients (8 with anaplastic pleomorphic xanthoastrocytoma, 9 with pleomorphic xanthoastrocytoma); and DSC-PWI, in 9 patients (5 with anaplastic pleomorphic xanthoastrocytoma, 4 with pleomorphic xanthoastrocytoma). Demographics, conventional imaging characteristics (location, size, cystic degeneration, enhancement, peritumoral edema, and leptomeningeal contact), minimum relative ADC ratio, and maximum relative CBV ratio were evaluated between the anaplastic pleomorphic xanthoastrocytoma and pleomorphic xanthoastrocytoma groups. RESULTS: Anaplastic pleomorphic xanthoastrocytoma was more likely to demonstrate high-grade features than pleomorphic xanthoastrocytoma, including greater maximum tumor diameter (4.7 ± 0.6 cm versus 3.1 ± 1.1 cm, P = .001), more frequent heterogeneous contrast enhancement of solid portions (88.9% versus 20.0%, P = .01), more obvious peritumoral edema (2.3 ± 0.9 cm versus 1.0 ± 0.9 cm, P = .008), lower minimum relative ADC on DWI (1.0 ± 0.2 versus 1.5 ± 0.4, P = .008), and higher maximum relative CBV on DSC-PWI (2.6 ± 0.8 versus 1.6 ± 0.2, P = .036). CONCLUSIONS: Anaplastic pleomorphic xanthoastrocytomas often have more aggressive MR imaging features mimicking high-grade astrocytomas than pleomorphic xanthoastrocytomas. DWI and DSC-PWI might be useful in the characterization and differentiation of anaplastic pleomorphic xanthoastrocytoma and pleomorphic xanthoastrocytoma.

Noninvasive Assessment of IDH Mutational Status in World Health Organization Grade II and III Astrocytomas Using DWI and DSC-PWI Combined with Conventional MR Imaging.

BACKGROUND AND PURPOSE: Isocitrate dehydrogenase (IDH) has been shown to have both diagnostic and prognostic implications in gliomas. The purpose of this study was to examine whether DWI and DSC-PWI combined with conventional MR imaging could noninvasively predict IDH mutational status in World Health Organization grade II and III astrocytomas. MATERIALS AND METHODS: We retrospectively reviewed DWI, DSC-PWI, and conventional MR imaging in 42 patients with World Health Organization grade II and III astrocytomas. Minimum ADC, relative ADC, and relative maximum CBV values were compared between IDH-mutant and wild-type tumors by using the Mann-Whitney U test. Receiver operating characteristic curve and logistic regression were used to assess their diagnostic performances. RESULTS: Minimum ADC and relative ADC were significantly higher in IDH-mutated grade II and III astrocytomas than in IDH wild-type tumors (P < .05). Minimum ADC with the cutoff value of ≥1.01 × 10-3 mm2/s could differentiate the mutational status with a sensitivity, specificity, positive predictive value, and negative predictive value of 76.9%, 82.6%, 91.2%, and 60.5%, respectively. The threshold value of <2.35 for relative maximum CBV in the prediction of IDH mutation provided a sensitivity, specificity, positive predictive value, and negative predictive value of 100.0%, 60.9%, 85.6%, and 100.0%, respectively. A combination of DWI, DSC-PWI, and conventional MR imaging for the identification of IDH mutations resulted in a sensitivity, specificity, positive predictive value, and negative predictive value of 92.3%, 91.3%, 96.1%, and 83.6%. CONCLUSIONS: A combination of conventional MR imaging, DWI, and DSC-PWI techniques produces a high sensitivity, specificity, positive predictive value, and negative predictive value for predicting IDH mutations in grade II and III astrocytomas. The strategy of using advanced, semiquantitative MR imaging techniques may provide an important, noninvasive, surrogate marker that should be studied further in larger, prospective trials.

[IgG4-related lung disease: analysis of 8 cases and literature review].

Objective: To improve the understanding and treatment of IgG4-related lung disease (IgG4-RLD). Methods: The clinical characteristics, serum IgG4 levels, pathological features, chest CT, therapy and prognosis of 8 patients with IgG4-RLD were retrospectively analyzed. These patients were admitted to the People's Liberation Army General Hospital and the pathological diagnosis was made between December 2005 and March 2016. Relevant literatures were reviewed. Results: The 8 patients with IgG4-RLD included 4 men and 4 women, with an average age of (59±4) years (range, 37-74). The respiratory symptoms included shortness of breath, cough, and expectoration. Extra-pulmonary symptoms included abdominal pain, facial edema, and fever. Extrapulmonary organs were involved in 7 cases. Serum IgG4 levels were elevated in 8 cases, with an average concentration of(17±6)g/L. Chest CT showed solid lung nodules in 6, alveolar-interstitial infiltration in 5, bronchovascular lesions in 3 and ground glass shadows in 2 cases. PET/CT was performed in 2 cases and it showed multiple organ involvement with higher radioactivity uptake(SUVmax2.9-4.2). The pathological examination found lymphocyte and plasma cell infiltration in 7, fibrous tissue hyperplasia in 5, and occlusive vasculitis in 2 cases. On immunohistochemical staining, the ratio of IgG4-positive plasma cells to IgG-positive plasma cells was higher than 40%in 3 cases. The number of IgG4-positive plasma cells was 10-50/HP in 8 cases. The misdiagnosis rate was 100% before the final diagnosis was made. Three cases received glucocorticoids with immunosuppressant therapy, 2 received surgery combined with glucocorticoid therapy, 2 received glucocorticoid therapy alone, and 1 only received surgery. The follow-up time was 4-132 months, with remission in 7 cases, and disease progression in 1 case, but no death. A total of 195 cases of IgG4-RLD were reviewed from the literature, among whom 111 cases were admitted with respiratory symptoms, 144 with extra-pulmonary involvement. Serum IgG4 levels were detected in 179 cases, with an average concentration of 5.408 g/L. The nodular type was predominant, accounting for 36.9%. Of these cases, 178 received glucocorticoid treatment with disease remission. Conclusions: The major clinical manifestations of IgG4-RLD were shortness of breath, cough and expectoration. Multiple organ lesions were common. The misdiagnosis rate was extremely high. The diagnosis could be made based on pathological features and IgG4 serum levels . Glucocorticoid treatment was effective.

Differentiating Hemangioblastomas from Brain Metastases Using Diffusion-Weighted Imaging and Dynamic Susceptibility Contrast-Enhanced Perfusion-Weighted MR Imaging.

BACKGROUND AND PURPOSE: On DWI and DSC-PWI, hemangioblastomas and brain metastases may exhibit different signal intensities depending on their cellularity and angiogenesis. The purpose of this study was to evaluate whether a hemangioblastoma can be differentiated from a single brain metastasis with DWI and DSC-PWI. MATERIALS AND METHODS: We retrospectively reviewed DWI, DSC-PWI, and conventional MR imaging of 21 patients with hemangioblastomas and 30 patients with a single brain metastasis. Variables of minimum ADC and relative ADC were acquired by DWI and the parameter of relative maximum CBV, by DSC-PWI. Minimum ADC, relative ADC, and relative maximum CBV values were compared between hemangioblastomas and brain metastases by using the nonparametric Mann-Whitney test. The sensitivity, specificity, positive and negative predictive values, accuracy, and the area under the receiver operating characteristic curve were determined. RESULTS: Both the minimum ADC values and relative ADC ratios were significantly higher in hemangioblastomas compared with brain metastases (P < .001 for both minimum ADC values and relative ADC ratios). The same was true for the relative maximum CBV ratio (P < .002). The threshold value of ≥6.59 for relative maximum CBV provided sensitivity, specificity, and accuracy of 95.24%, 53.33%, and 70.59%, respectively, for differentiating hemangioblastomas from brain metastases. Compared with relative maximum CBV, relative ADC had high sensitivity (95.24%), specificity (96.67%), and accuracy (96.08%) using the threshold value of ≥1.54. The optimal threshold value for minimum ADC was ≥1.1 × 10-3 mm2/s. CONCLUSIONS: DWI and DSC-PWI are helpful in the characterization and differentiation of hemangioblastomas from brain metastases. DWI appears to be the most efficient MR imaging technique for providing a distinct differentiation of the 2 tumor types.

[The diagnosis and treatment strategy for patients with severemultispace abscesses in neck].

Objective:To analyze the clinical characteristics of patients with severe deep neck abscess,etiology,imaging,appropriate treatment selection in those patients,to improve the judgement and understanding of the disease.Method:Thirty cases of severe deep neck abscess treated from March 2010 to June 2015 were retrospectively reviewed,including the clinical characteristics,diagnosis and treatment strategy.Result:The sore throat,odynophagia,dysphagia,fever and difficulty breathing were the most common symptoms of severe deep neck abscess.The causes of deep neck abscess were tooth diseases(5 cases),foreign bodies in pharynx or esophagus(4 cases),the second branchial crack cyst with multiply abscess,uncertain cause(20 cases).Six of the above cases complicated with mediastinal abscess.Radiologic evaluation was performed on all of the patients to identify the most probable location of the abscess:parapharyngeal space,retropharyngeal space,masticator space,carotid space,etc.Twenty-five cases were treated by drainage via incising lateral neck and 4 patientsreceived abscess puncture aspiration.Life-threatening complications were developed in all cases,29 cases were cured but one case dead.Conclusion:The treatment of severe deep neck multispace abscesses should be mindful.Once deep neck abscesses are diagnosed,we should timely undertake surgical drainage via incising lateral neck.Emergency tracheostomy should be perform in some case like severe dyspnea,airway obstrucion.Antibiotics should be appropriately applied,and basic diseases and complications should be carefully controlled.

Differentiation of hemangioblastomas from pilocytic astrocytomas using 3-T magnetic resonance perfusion-weighted imaging and MR spectroscopy.

INTRODUCTION: Hemangioblastomas and pilocytic astrocytomas (PAs) present similar imaging features on conventional MR imaging, making differential diagnosis a challenge. The purpose of this study was to evaluate the usefulness of dynamic susceptibility-weighted contrast-enhanced perfusion-weighted imaging (DSC-PWI) and proton MR spectroscopic imaging in the differentiation of hemangioblastomas and PAs. METHODS: A 3.0-T MR imaging unit was used to perform DSC-PWI and conventional MR imaging on 14 patients with hemangioblastomas and 22 patients with PAs. Four patients with hemangioblastomas and 10 PA patients also underwent proton MR spectroscopy. Parameters of relative peak height (rPH) and relative percentage of signal intensity recovery (rPSR) were acquired by DSC-PWI and variables of N-acetylaspasrtate (NAA)/creatine (Cr), choline (Cho)/Cr, and lactate-lipid (Lac-Lip)/Cr by MR spectroscopy. The sensitivity, specificity, and the area under the receiver operating characteristic curve of all analyzed parameters at respective cutoff values were determined. RESULTS: Higher rPH but lower rPSR values were detected in hemangioblastomas compared to PAs. The NAA/Cr ratio was significantly lower in hemangioblastomas compared with PAs. The threshold values ≥3.2 for rPH provide sensitivity, specificity, positive predictive values, and negative predictive values of 85.7, 95.5, 92.3, and 91.3%, respectively, for differentiating hemangioblastomas from PAs. The optimal threshold values were ≤0.9 for rPSR and ≤1.5 for NAA/Cr ratios in tumor. CONCLUSION: Significantly higher rPH and lower NAA/Cr were seen in patients with hemangioblastomas when compared with PA patients, suggesting that DSC-PWI and proton MR spectroscopy are helpful in the characterization and differentiation of these two types of tumors.

Supratentorial hemangioblastomas: three case reports and review of the literature.

Hemangioblastoma (HBL) within the central nervous system is a benign vascular neoplasm that usually occurs in the cerebellum. Supratentorial occurrence of HBL is an extremely rare event. Till date, approximately 129 cases of supratentorial HBL have been reported in the literature. Here, we present three new cases of supratentorial hemangioblatomas, one of which was found to have the lesions in a unique location of the choroidal fissure. The clinical, histopathological, and neuroradiological characteristics, as well as management of this rare disease are discussed with a review of the pertinent literature.

Molecular cloning of a peptidase against N-acetylaspartylglutamate from a rat hippocampal cDNA library.

N-Acetylaspartylglutamate (NAAG) is the most prevalent peptide neurotransmitter in the mammalian nervous system. NAAG selectively activates the type 3 metabotropic glutamate receptor. It is inactivated by peptidase activity on the extracellular face of the plasma membrane of neurons and glia. The human gene that codes for prostate-specific membrane antigen (PSM) has been shown to produce peptidase activity against NAAG. We cloned the human PSM cDNA and used it to probe a rat hippocampal cDNA library. We identified a cDNA containing a complete coding region that possesses 83% homology with the PSM gene. The predicted 752-amino acid sequence has 85% identity and 91% similarity to the PSM sequence. CHO cells transfected with this cDNA expressed NAAG peptidase activity at a level similar to that obtained from rat brain membranes. The peptidase activity was inhibited by beta-NAAG, quisqualate, and pteroylglutamate but not aspartylglutamate or pteroic acid. In situ hybridization data demonstrated the widespread distribution of the peptidase mRNA in the brain, consistent with the distribution of peptidase activity. The highest levels of hybridization were detected in the hippocampus, dentate gyrus, piriform cortex, choroid plexus of the ventricles, pineal gland, anterior pituitary, and supraoptic nucleus. Three transcripts (estimated at 5, 3.4, and 2.9 kb) were identified in northern blots of rat brain, while in rat kidney the third transcript appeared slightly smaller than 2.9 kb. With use of reverse transcriptase PCR with primers for the 5' end, the central region, and the 3' end of the hippocampal cDNA, the expected amplification products were obtained from rat brain RNA. Spinal cord yielded an amplification product only with primers for the 5' end of the hippocampal cDNA.