Characterization of parotid gland tumors using diffusion-relaxation correlation spectrum imaging: a preliminary study

AIM

To assess the performance of diffusion-relaxation correlation spectrum imaging (DR-CSI) in the characterization of parotid gland tumors.

MATERIALS AND METHODS

Twenty-five pleomorphic adenomas (PA) patients, 9 Warthin's tumors (WT) patients and 7 malignant tumors (MT) patients were prospectively recruited. DR-CSI (7 b-values combined with 5 TEs, totally 35 diffusion-weighted images) was scanned for pre-treatment assessment. Diffusion (D)-T2 signal spectrum summating all voxels were built for each patient, characterized by D-axis with range 0∼5 × 10-3 mm2/s, and T2-axis with range 0∼300ms. With boundaries of 0.5 and 2.5 × 10-3 mm2/s for D, all spectra were divided into three compartments labeled A (low D), B (mediate D) and C (high D). Volume fractions acquired from each compartment (VA, VB, VC) were compared among PA, WT and MT. Diagnostic performance was assessed using receiver operating characteristic analysis and area under the curve (AUC).

RESULTS

Each subtype of parotid tumors had their specific D-T2 spectrum. PA showed significantly lower VA (8.85 ± 4.77% vs 20.68 ± 10.85%), higher VB (63.40 ± 8.18% vs 43.05 ± 7.16%), and lower VC (27.75 ± 8.51% vs 36.27 ± 11.09) than WT (all p<0.05). VB showed optimal diagnostic performance (AUC 0.969, sensitivity 92.00%, specificity 100.00%). MT showed significantly higher VA (21.23 ± 12.36%), lower VB (37.09 ± 6.43%), and higher VC (41.68 ± 13.72%) than PA (all p<0.05). Similarly, VB showed optimal diagnostic performance (AUC 0.994, sensitivity 96.00%, specificity 100.00%). No significant difference of VA, VB and VC was found between WT and MT.

CONCLUSIONS

DR-CSI might be a promising and non-invasive way for characterizing parotid gland tumors.

[Health economic evaluation of telemedicine diabetic retinopathy examination using a non-mydriatic fundus camera in China]

Objective: To perform a health economic evaluation of telemedicine diabetic retinopathy (DR) examination with a non-mydriatic fundus camera in China and to investigate the optimal examination interval. Methods: Based on 18 peer-reviewed articles related to epidemiology, clinical trial, and health economic evaluation of DR, surveys from 9 ophthalmologists in 3 tertiary hospitals in China, price lists for medical services in each province, and the negotiated price in 2021, a Markov model was conducted to evaluate the cost utility of telemedicine eye examination for diabetes mellitus patients aged 45 and older from the health system perspective. Separate analyses were performed for no examination and for examination intervals of every 1 to 5 years to predict the lifetime health gain, including cumulative days of blindness, cumulative life years, and quality-adjusted life years (QALYs), and costs for unilateral and bilateral direct medication with a 3.5% discount rate. Results: The cumulative days of blindness in the absence of a DR screening were 2 375.00 days, and ranged from 701.00 to 738.00 days for five different DR screening interval programs. The cumulative life years for no screening and five DR screening programs ranged from 27.120 34 to 28.005 00 years, with QALYs ranging from 9.502 96 to 9.875 02. The direct medication costs in the absence of a DR screening program were 72 785.00 yuan for both unilateral and bilateral scenarios. For the five DR screening intervals, the direct medication costs ranged from 52 065.00 to 52 408.00 yuan for unilateral and 79 100.00 to 79 603.00 yuan for bilateral. Comparing the incremental cost-effectiveness ratios between the DR screening intervals and no screening, the 1-to 5-year intervals were dominant in the unilateral scenario (between -56 368.54 and -55 523.75 yuan/QALY). In the bilateral scenario, the ratios ranged from 17 469.07 to 18 325.15 yuan/QALY. Using a willingness-to-pay threshold equal to the per capita GDP (80 976 yuan/QALY), the 1-year DR screening interval had an 85.9% probability of being cost-effective and a 55.2% probability of being dominant in the unilateral scenario. In the bilateral scenario, the 2-year interval held a 61.4% probability of being cost-effective. Conclusions: Analyses on the remote fundus consultation in diabetic patients and health economics based on the Markov model indicate that telemedicine DR examination through a non-mydriatic fundus camera can be effectively employed for diabetes mellitus patients in China. DR examination every two years is recommended for general diabetic patients, and DR examination every year may be chosen in developed areas.

[Clinical analysis of 26 children with postoperative residual or recurrent fibrosarcoma]

Objective: To evaluate the long-term outcomes and prognostic factors of postoperative residual or recurrent fibrosarcoma in children. Methods: Clinical data of 26 patients continually admitted to Shanghai Children's Medical Center between April 2004 and February 2019 with postoperative residual or recurrent fibrosarcoma were analyzed retrospectively. All patients were treated with Shanghai Children's Medical Center-rhabdomyosarcoma-1999 (SCMC-RS-99) regimen and timely radical tumor resection. Before chemotherapy, according to the surgery and imaging examination, 26 patients were divided into 2 groups: postoperative residual group and postoperative recurrent group. Clinical features and long-term follow-up results of patients were summarized. Kaplan-Meier analysis was used to evaluate the overall survival (OS) and event-free survival (EFS) rates, Log-Rank test and Cox proportional hazards models were used for univariate and multivariate prognostic analysis of factors including age (<3 years or 3-18 years old), gender, primary tumor site, postoperative stage, disease status, ETS variant 6 (ETV6) gene and chemotherapy drugs. Results: Among 26 cases, 13 were male and 13 were female, 17 cases were in postoperative residual group and 9 cases were in postoperative recurrent group. Until the last follow-up at December 31, 2019, the median follow-up time was 73 months (ranged from 10 to 188 months).The 5-year OS and EFS rates were (86±7)% and (77±9)%. Univariate analysis showed that, the 5-year EFS rate of postoperative residual group was significantly higher than that of the postoperative recurrent group ((94±5)% vs.(63±16)%,χ(2)=5.106,P=0.024), the 5-year EFS rate of patients <3 years old was significantly higher than that of patients 3-18 years old ((94±5)% vs. (62±17)%, χ(2)=6.507, P=0.011). Gender (χ(2)=0.445), primary tumor site (χ(2)=0.258), postoperative stage (χ(2)=3.046), ETV6 gene (χ(2)=1.496), and whether doxorubicin-containing drugs in chemotherapy (χ(2)=1.692) did not exhibit significant impact on 5-EFS rate (all P>0.05). Age, postoperative stage and disease status were included in COX proportional risk model for multivariate analysis, which showed that age >3 years old (HR=8.95, 95%CI 0.73-109.50, P=0.086), stage Ⅲ-Ⅳ (HR=16.50, 95%CI 0.84-321.40, P=0.065) and postoperative recurrence (HR=10.60, 95%CI 0.84-134.30, P=0.068) had no significant impact on EFS rate. Conclusion: Children with postoperative residual or postoperative recurrent fibrosarcoma still had good remission rate and long-term survival, especially young children without recurrence have a significant survival advantage.

[Relationship between expression level of sex-determining region Y box 9 and metastasis of oral squamous cell carcinoma]

Objective: To investigate the effects of sex-detemining region Y box9 (SOX9) expression levels on the proliferation, migration and metastasis in oral squamous cell carcinoma (OSCC). Methods: A total of 74 OSCC pathological specimens were collected from Shanghai OSCC Tissue and Biological Informations Bank, and clinicopathological information of these specimens were collected. Immunohistochemistry assay was used to examine the expression levels of SOX9 in OSCC and to analyze their relationship with clinicopathological features. Cell counting kit-8 assay and cloning formation was used to observe the relationship between the expression levels of SOX9 and the proliferation of OSCC. Transwell experiment and scratch test were used to detect the difference of the ability of OSCC in cell lines with different expression levels of SOX9. Results: The risk of lymph node metastasis in patients with high expression of SOX9 was significantly increased (P=0.010). In the Transwell experiment, the number of HN6 cells (671.0±57.4, P=0.000) migrated to the lower chamber more than that of CAL27 cells (172.0±13.9). In the scratch experiment, HN6 cells [0 h: (93.7±2.1) μm; 6 h: (56.7±2.5) μm; 12 h: (29.7±3.1) μm] migrated faster than CAL27 [0 h: (93.7±1.5) μm; 6 h: (78.0±2.0) μm; 12 h: (42.0±3.0) μm](P<0.05). The migration ability of the cell line (HN6) with high-expression of SOX9 was significantly higher than that in cell line (CAL27) with low-expression SOX9 (P<0.05). The expression levels of SOX9 in OSCC were no significant on cell proliferation (P>0.05). Conclusions: High expression of SOX9 can promote the migration and lymph node metastasis of OSCC. SOX9 is a candidate gene target for the diagnosis and intervention of lymph node metastasis in OSCC.

[A long-term follow-up report of pediatric relapsed Wilms tumor after retreatment]

Objective: To investigate the long-term efficacy and prognostic factors of pediatric relapsed Wilms tumor (WT) after retreatment. Method: Sixteen children in Shanghai Children's Medical Center with relapsed Wilms tumor were enrolled consecutively in this study between April 2006 and June 2016. All patients were diagnosed according to pathology, imaging and medical and surgical oncologist's assistance. Relapse treatment included surgical excision, chemotherapy and selective radiation therapy. The clinical features, long-term outcomes and prognostic factors of patients were analyzed retrospectively.Survival data were analyzed by Kaplan-Meier.Log-Rank analysis was used for univariate analysis. Result: One case was excluded because of giving up the therapy even though no disease progress was identified. A total of 15 cases (5 males and 10 females) were included in this study. The median age at diagnosis was 3.8 years (range 0.5-9.1 years). The tumor staging at diagnosis included one case of stageⅠ, 7 cases of stageⅡand 7 cases of stage Ⅲ. Among cases of stage Ⅲ, 6 cases had radiation therapy history. The pathology of all patients' recurrent tumor was favorable histology (FH). The median follow-up time was 34.6 months (range 12.5-132.7 months) until March 21, 2017. The time from initial diagnosis to relapse was 7.9 months (range 3.1-17.9 months). Four cases experienced local recurrence, 9 cases relapsed with metastases (6 cases in lungs, 2 in livers, 1 in mediastinum) and 2 cases relapsed in both local site and with metastases. Except to 2 cases received irregular retreatment, 13 cases received regimen I (doxorubicin, vincristine, epoposide and cyclophosphamide for 25 weeks) as relapsed chemotherapy. Five cases received autologous bone marrow transplantation (ABMT). Until the last follow-up, 8 cases achieved continuous complete remission (range 6.7-104.3 months), 3 cases had relapse again or progressing and 4 cases died. The estimated 5-year overall survival (OS) rate and event free survival (EFS) rate were (70±15)% and (52±15)%. According to whether received ABMT or not, the 5-year EFS rate were 51% and 53%. According to whether relapsed within 6 months after diagnosis or not, the 5-year EFS rate were 38% and 56% respectively. Conclusion: The 5-year EFS rate of pediatric relapsed FH WT have reached above 50% by multi-disciplinary treatment in our experience and we encourage patients and doctors to receive retreatment.

[A follow-up report of childhood hepatoblastoma from 74 cases in a single center]

Objective: To investigate the efficacy and the prognostic factors in pediatric hepatoblastoma according to the standard diagnostic and therapeutic regimen. Method: Eighty-four consecutive patients were enrolled in this study between June 2000 and June 2015. Diagnosis and staging was decided by the multi-disciplinary team including oncologists, surgeons, pathologists and sub-specialized radiologists refering to protocol of Children's Oncology Group(COG) and International Society of Pediatric Oncology Liver Tumor Study Group (SIOPEL) in a case observational study. Univariate analysis was tested by the log-rank and multivariate analysis by COX regression. All consecutive cases were divided into low risk group and high risk group according to grouping criteria. Complete remission was defined as both imaging negative and α fetoprotein (AFP) normalization. Retrospective analysis was performed in clinical features, long-term outcomes and prognostic factors. Result: Ten patients were excluded because of giving up after less than or equal to three cycles of treatment. A total of 74 cases were included in this study; 45 males and 29 females. The median age at diagnosis was 1.7 years(range 0.2-14.8 years). Untill August 30, 2016, the median follow-up time was 24.2 months (range 4.1-135.3 months); 59 cases achieved complete remission.The estimated five years overall survival (OS) and event free survival(EFS) were 90%(68/74)and 72%(58/74). AFP could be normalized after 5 circles of treatment or 2 circles of postoperation.In univariate analysis , the five years OS and EFS in low risk group were both 100%(18/18), and those in high risk group were 88%(50/56)and 68%(40/56), respectively. The five years OS rates were 75%(15/19) and 95%(53/55) in patients with or without distant metastasis (P=0.016). After 3 cycles of chemotherapy post tumor resection, we divided these patients into 2 groups according to AFP recover or not, the five years OS were 100%(43/43)and 81%(22/26), respectively (P=0.011). Conclusion: The result of this protocol is reasonable when comparing with other worldwide research. Except for staging, metastasis, pathological subtypes, postoperative AFP recover or not is a prognostic factor after 3 cycles of chemotherapy.

[Clinical analysis of 51 cases with rare childhood soft tissue sarcomas]

Objective: To analyze the clinical characteristics and prognosis of rare soft tissue sarcomas. Method: Clinical data of 51 patients with rare soft tissue sarcomas including fibrosarcoma, synovial sarcoma, extrarenal rhabdoid tumor, alveolar soft part sarcoma, desmoplastic small round cell tumor and undifferentiated sarcoma in children and adolescents, diagnosed at Shanghai Children's Medical Center from June 1998 to December 2013, were retrospectively analyzed. All types were treated with the same strategy and chemotherapy regimens. Their clinical features, treatment and prognosis were discussed. Result: Seventeen patients with fibrosarcoma, 10 with synovial sarcoma, 9 with extrarenal rhabdoid tumor, 6 with alveolar soft part sarcoma, 3 with desmoplastic small round cell tumor and 6 with undifferentiated sarcoma were included. The mean age at initial diagnosis was 5 years(range from 1 month to 13.5 years). The most common primary site of tumors was limbs, followed by the thoracic and abdominal cavity, accounting for 41% and 24% respectively. Twelve cases presented distant tissue or organ involvement in which bone metastases occupied the first place. Seven cases(accounting for 14%)were at stage Ⅰ, 13 cases were at stage Ⅱ(accounting for 25%), 19 cases were at stage Ⅲ(accounting for 37%) and 12 cases were at stage Ⅳ(accounting for 24%). The median follow-up period was 36 months(range from 1 month to 123 months). Forty-four patients achieved complete remission and 3 patients achieved partial remission after initial treatment, the overall response rate was 92%. Subsequent follow-up showed 29 patients remained relapse-free while 13 patients had relapsed disease. Overall survival and event-free survival at 2 years were 88% and 57%.Postoperative surgical staging was the main prognostic factors. Patients with stage Ⅲ+ Ⅳ had poorer results than those with Ⅰ+ Ⅱ (χ²=4.909, P=0.027). Conclusion: These 6 types of soft tissue sarcomas are rare in children and adolescents. The tumor can occur anywhere in the body but commonly presents in the extremities. Complete resection of tumor remains the most important modality of treatment and is directly related to prognosis. Neoadjuvant chemotherapy helps improve the resection rate of some unresectable tumors at diagnosis. Radiation therapy is primarily adopted for focal tumor control.

Novel CSF biomarkers for frontotemporal lobar degenerations

OBJECTIVE

To identify antemortem CSF diagnostic biomarkers that can potentially distinguish between the 2 main causes of frontotemporal lobar degeneration (FTLD), i.e., FTLD with TDP-43 pathology (FTLD-TDP) and FTLD with tau pathology (FTLD-tau).

METHODS

CSF samples were collected antemortem from 23 patients with FTLD with known pathology to form a autopsy cohort as part of a comparative biomarker study that additionally included 33 living cognitively normal subjects and 66 patients with autopsy-confirmed Alzheimer disease (AD). CSF samples were also collected from 80 living patients clinically diagnosed with frontotemporal dementia (FTD). Levels of 151 novel analytes were measured via a targeted multiplex panel enriched in neuropeptides, cytokines, and growth factors, along with levels of CSF biomarkers for AD.

RESULTS

CSF levels of multiple analytes differed between FTLD-TDP and FTLD-tau, including Fas, neuropeptides (agouti-related peptide and adrenocorticotropic hormone), and chemokines (IL-23, IL-17). Classification by random forest analysis achieved high sensitivity for FTLD-TDP (86%) with modest specificity (78%) in the autopsy cohort. When the classification algorithm was applied to a living FTD cohort, semantic dementia was the phenotype with the highest predicted proportion of FTLD-TDP. When living patients with behavioral variant FTD were examined in detail, those predicted to have FTLD-TDP demonstrated neuropsychological differences vs those predicted to have FTLD-tau in a pattern consistent with previously reported trends in autopsy-confirmed cases.

CONCLUSIONS

Clinical cases with FTLD-TDP and FTLD-tau pathology can be potentially identified antemortem by assaying levels of specific analytes that are well-known and readily measurable in CSF.

Distinct cerebral perfusion patterns in FTLD and AD

OBJECTIVE

We examined the utility of distinguishing between patients with frontotemporal lobar degeneration (FTLD) and Alzheimer disease (AD) using quantitative cerebral blood flow (CBF) imaging with arterial spin labeled (ASL) perfusion MRI.

METHODS

Forty-two patients with FTLD and 18 patients with AD, defined by autopsy or CSF-derived biomarkers for AD, and 23 matched controls were imaged with a continuous ASL method to quantify CBF maps covering the entire brain.

RESULTS

Patients with FTLD and AD showed distinct patterns of hypoperfusion and hyperperfusion. Compared with controls, patients with FTLD showed significant hypoperfusion in regions of the frontal lobe bilaterally, and hyperperfusion in posterior cingulate and medial parietal/precuneus regions. Compared with controls, patients with AD showed significant hypoperfusion in the medial parietal/precuneus and lateral parietal cortex, and hyperperfusion in regions of the frontal lobe. Direct comparison of patient groups showed significant inferior, medial, and dorsolateral frontal hypoperfusion in FTLD, and significant hypoperfusion in bilateral lateral temporal-parietal and medial parietal/precuneus regions in AD.

CONCLUSIONS

Doubly dissociated areas of hypoperfusion in FTLD and AD are consistent with areas of significant histopathologic burden in these groups. ASL is a potentially useful biomarker for distinguishing patients with these neurodegenerative diseases.

Multimodal predictors for Alzheimer disease in nonfluent primary progressive aphasia

OBJECTIVE

Alzheimer disease (AD) and frontotemporal lobar degeneration (FTLD) are hypothesized to cause clinically distinct forms of primary progressive aphasia (PPA) that predominantly affect expressive speech. AD is thought to cause logopenic progressive aphasia (LPA), and FTLD may cause progressive nonfluent aphasia (PNFA). We sought to determine the value of clinical characterization, neuropsychological analysis, and MRI atrophy in predicting pathology of LPA and PNFA.

METHODS

Patients with LPA (n = 19) and patients with PNFA (n = 19) were evaluated with neuropsychological assessments, structural MRI, CSF analysis, and neuropathologic examination.

RESULTS

Twelve of 19 patients with LPA (63%) and 6 of 19 patients with PNFA (32%) had neuropathologic findings or CSF biomarkers consistent with AD. Neuropsychological testing showed that naming was more impaired in patients with AD, and letter-guided fluency was more affected in patients with a non-AD disorder. Voxel-based morphometry analysis revealed that in patients with AD, patients with LPA and PNFA had significant posterior-superior temporal atrophy; in patients with non-AD, patients with LPA had peri-Sylvian atrophy and patients with PNFA had dorsolateral prefrontal and insular atrophy. Receiver operator characteristic curve analysis showed that combining neuropsychological testing with MRI atrophy pattern had 90% specificity for pathology or CSF biomarkers consistent with AD, and combining clinical features with neuropsychological analysis had 100% sensitivity for pathology or CSF biomarkers consistent with AD.

CONCLUSIONS

Neither PPA phenotyping nor imaging alone is a reliable predictor of pathology. Multimodal predictors, such as combining neuropsychological testing with MRI analysis, can improve noninvasive prediction of underlying pathology in nonfluent forms of PPA.

Abnormal TDP-43 immunoreactivity in AD modifies clinicopathologic and radiologic phenotype

BACKGROUND

TAR DNA-binding protein 43 (TDP-43) is one of the major disease proteins in frontotemporal lobar degeneration with ubiquitin immunoreactivity. Approximately one-fourth of subjects with pathologically confirmed Alzheimer disease (AD) have abnormal TDP-43 (abTDP-43) immunoreactivity. The aim of this study was to determine whether subjects with pathologically confirmed AD and abTDP-43 immunoreactivity have distinct clinical, neuropsychological, imaging, or pathologic features compared with subjects with AD without abTDP-43 immunoreactivity.

METHODS

Eighty-four subjects were identified who had a pathologic diagnosis of AD, neuropsychometric testing, and volumetric MRI. Immunohistochemistry for TDP-43 was performed on sections of hippocampus and medial temporal lobe, and positive cases were classified into one of three types. Neuropsychometric data were collated and compared in subjects with and without abTDP-43 immunoreactivity. Voxel-based morphometry was used to assess patterns of gray matter atrophy in subjects with and without abTDP-43 immunoreactivity compared with age- and sex-matched controls.

RESULTS

Twenty-nine (34%) of the 84 AD subjects had abTDP-43 immunoreactivity. Those with abTDP-43 immunoreactivity were older at onset and death and performed worse on the Clinical Dementia Rating scale, Mini-Mental State Examination, and Boston Naming Test than subjects without abTDP-43 immunoreactivity. Subjects with and without abTDP-43 immunoreactivity had medial temporal and temporoparietal gray matter loss compared with controls; however, those with abTDP-43 immunoreactivity showed greater hippocampal atrophy. Multivariate logistic regression adjusting for age at death demonstrated that hippocampal sclerosis was the only pathologic predictor of abTDP-43 immunoreactivity.

CONCLUSIONS

The presence of abnormal TDP-43 immunoreactivity is associated with a modified Alzheimer disease clinicopathologic and radiologic phenotype.

Progressive aphasia secondary to Alzheimer disease vs FTLD pathology

BACKGROUND

The pathology causing progressive aphasia is typically a variant of frontotemporal lobar degeneration, especially with ubiquitin-positive inclusions (FTLD-U). Less commonly the underlying pathology is Alzheimer disease (AD).

OBJECTIVE

To compare clinicopathologic and MRI features of subjects with progressive aphasia and AD pathology to subjects with aphasia and FTLD-U pathology and subjects with typical AD.

METHODS

We identified 5 subjects with aphasia and AD pathology and 5 with aphasia and FTLD-U pathology with an MRI from a total of 216 aphasia subjects. Ten subjects with typical AD clinical features and AD pathology were also identified. All subjects with AD pathology underwent pathologic reanalysis with TDP-43 immunohistochemistry. Voxel-based morphometry (VBM) was used to assess patterns of gray matter atrophy in the aphasia cases with AD pathology, aphasia cases with FTLD-U, and typical AD cases with AD pathology, compared with a normal control group.

RESULTS

All aphasic subjects had fluent speech output. However, those with AD pathology had better processing speed than those with FTLD-U pathology. Immunohistochemistry with TDP-43 antibodies was negative. VBM revealed gray matter atrophy predominantly in the temporoparietal cortices, with notable sparing of the hippocampus in the aphasia with AD subjects. In comparison, the aphasic subjects with FTLD-U showed sparing of the parietal lobe. Typical AD subjects showed temporoparietal and hippocampal atrophy.

CONCLUSIONS

A temporoparietal pattern of atrophy on MRI in patients with progressive fluent aphasia and relatively preserved processing speed is suggestive of underlying Alzheimer disease pathology rather than frontotemporal lobar degeneration with ubiquitin-only immunoreactive changes.

Effect of food on the pharmacokinetics of osmotic controlled-release methylphenidate HCl in healthy subjects

The effect of a high-fat meal on the pharmacokinetics of OROS(R) (methylphenidate HCl), an osmotic controlled-release formulation of methylphenidate HCl, was investigated in healthy subjects. Mean peak methylphenidate plasma concentrations occurred slightly later and peak methylphenidate plasma concentrations and AUC values were slightly higher (approximately 10-30%) in the presence of food than in the absence of food. There was no difference in the plasma elimination half-life of methylphenidate between the fed and fasted state. Similarly, peak concentrations and AUC values for alpha-phenyl-2-piperidine acetic acid (PPA; ritalinic acid), the major metabolite of methylphenidate, were slightly higher in the presence of food than in its absence. The 90% confidence interval (CI) for the treatment ratio (fed/fasted) for C(max) was 120.6%-140. 0% for the 18-mg dose and 105.4-119.3% for a 36-mg dose. The 90% CI for the treatment ratio for AUC(infinity) was 114.6-125.7% for the 18-mg dose and 115.1-124.6% for the 36-mg dose. PPA levels were measured following the 18-mg dose and the 90% CI of the treatment ratio was 106.8-115.4% for C(max) and 97.9-103.6% for AUC(infinity). These results indicate the absence of dose dumping from OROS (methylphenidate HCl) in the presence of food. Food does not impede drug absorption and OROS (methylphenidate HCl) may be administered in the fed or fasted state. There were no differences in the adverse event profile between the fed and fasted state.

[Research on hydrokinetics of self-intermittent vaccum root canal drainage]

A hydrokinetically simulated sucking was made to study the self-intermittent vacuum drainage of the root canal.Results showed that due to the shape difference between diameters at the upper and lower parts of the canal,the high-speed air-flow at the lower-end opening can drain the fluid below the opening out while the lower-speed air-flow at the upper opening is not likely to make the saliva and see page in the oral cavity reenter the root cavity.The above mentioned are in conformity with the Bernoulli's equation.

Compact, magneto-optic Q-switched, neodymium-doped bismuth germinate crystal (Nd:BGO) laser pumped by a laser diode

The magneto-optic Q-switched operation of a neodymium-doped bismuth germinate crystal (Nd:BGO) laser that is end pumped by a cw 500-mW laser diode is reported. The crystal is a new host for Nd lasers. Here it acts as a magneto-optic modulator as well as a laser medium. A pulse energy of 2 µJ with a FWHM of 100 ns has been obtained. The device operates at a repetition rate of 1 kHz, and the fluctuation of the shot-to-shot intensity is less than ±1%.