The two-back task leads to activity in the left dorsolateral prefrontal cortex in schizophrenia patients with predominant negative symptoms: a fNIRS study and its implication for tDCS

Transcranial direct current stimulation (tDCS) over left dorsolateral prefrontal cortex (DLPFC) has shown some potential as an adjunctive intervention for ameliorating negative symptoms of schizophrenia, but its efficacy requires optimization. Recently, 'functional targeting' of stimulation holds promise for advancing tDCS efficacy by coupling tDCS with a cognitive task where the target brain regions are activated by that task and further specifically polarized by tDCS.The study used 48-channel functional near infra-red spectroscopy (fNIRS) aiming to determine a cognitive task that can effectively induce a cortical activation of the left DLPFC in schizophrenia patients with predominant negative symptoms before running a tDCS trial. Sixty schizophrenia patients with predominant negative symptoms completed measures of clinical and psychosocial functioning characteristics and assessments across cognitive domains. Hemodynamic changes during n-back working memory tasks with different cognitive loads (1-back and 2-back) and verbal fluency test (VFT) were measured using fNIRS. For n-back tasks, greater signal changes were found when the task required elevated cognitive load. One sample t-test revealed that only 2-back task elicited significant activation in left DLPFC (t = 4.23, FDR-corrected p = 0.0007). During VFT, patients failed to show significant task-related activity in left DLPFC (one sample t-test, t = -0.25, FDR-corrected p > 0.05). Our study implies that 2-back task can effectively activate left DLPFC in schizophrenia patients with predominant negative symptoms. This neurophysiologically-validated task is considered highly potential to be executed in conjunction with high-definition tDCS for "functional targeting" of the left DLPFC to treat negative symptoms in a double-blind randomized sham-control trial, registered on ClinicalTrials.gov Registry (ID: NCT05582980).

Resting-State EEG Connectivity at High-Frequency Bands and Attentional Performance Dysfunction in Stabilized Schizophrenia Patients

Background and Objectives: Attentional dysfunction has long been viewed as one of the fundamental underlying cognitive deficits in schizophrenia. There is an urgent need to understand its neural underpinning and develop effective treatments. In the process of attention, neural oscillation has a central role in filtering information and allocating resources to either stimulus-driven or goal-relevant objects. Here, we asked if resting-state EEG connectivity correlated with attentional performance in schizophrenia patients. Materials and Methods: Resting-state EEG recordings were obtained from 72 stabilized patients with schizophrenia. Lagged phase synchronization (LPS) was used to measure whole-brain source-based functional connectivity between 84 intra-cortical current sources determined by eLORETA (exact low-resolution brain electromagnetic tomography) for five frequencies. The Conners' Continuous Performance Test-II (CPT-II) was administered for evaluating attentional performance. Linear regression with a non-parametric permutation randomization procedure was used to examine the correlations between the whole-brain functional connectivity and the CPT-II measures. Results: Greater beta-band right hemispheric fusiform gyrus (FG)-lingual gyrus (LG) functional connectivity predicted higher CPT-II variability scores (r = 0.44, p < 0.05, corrected), accounting for 19.5% of variance in the CPT-II VAR score. Greater gamma-band right hemispheric functional connectivity between the cuneus (Cu) and transverse temporal gyrus (TTG) and between Cu and the superior temporal gyrus (STG) predicted higher CPT-II hit reaction time (HRT) scores (both r = 0.50, p < 0.05, corrected), accounting for 24.6% and 25.1% of variance in the CPT-II HRT score, respectively. Greater gamma-band right hemispheric Cu-TTG functional connectivity predicted higher CPT-II HRT standard error (HRTSE) scores (r = 0.54, p < 0.05, corrected), accounting for 28.7% of variance in the CPT-II HRTSE score. Conclusions: Our study indicated that increased right hemispheric resting-state EEG functional connectivity at high frequencies was correlated with poorer focused attention in schizophrenia patients. If replicated, novel approaches to modulate these networks may yield selective, potent interventions for improving attention deficits in schizophrenia.

Online Left-Hemispheric In-Phase Frontoparietal Theta tACS Modulates Theta-Band EEG Source-Based Large-Scale Functional Network Connectivity in Patients with Schizophrenia: A Randomized, Double-Blind, Sham-Controlled Clinical Trial

EEG studies indicated that schizophrenia patients had increased resting-state theta-band functional connectivity, which was associated with negative symptoms. We recently published the first study showing that theta (6 Hz) transcranial alternating current stimulation (tACS) over left prefrontal and parietal cortices during a working memory task for accentuating frontoparietal theta-band synchronization (in-phase theta-tACS) reduced negative symptoms in schizophrenia patients. Here, we hypothesized that in-phase theta-tACS can modulate theta-band large-scale networks connectivity in schizophrenia patients. In this randomized, double-blind, sham-controlled trial, patients received twice-daily, 2 mA, 20-min sessions of in-phase theta-tACS for 5 consecutive weekdays (n = 18) or a sham stimulation (n = 18). Resting-state electroencephalography data were collected at baseline, end of stimulation, and at one-week follow-up. Exact low resolution electromagnetic tomography (eLORETA) was used to compute intra-cortical activity. Lagged phase synchronization (LPS) was used to measure whole-brain source-based functional connectivity across 84 cortical regions at theta frequency (5-7 Hz). EEG data from 35 patients were analyzed. We found that in-phase theta-tACS significantly reduced the LPS between the posterior cingulate (PC) and the parahippocampal gyrus (PHG) in the right hemisphere only at the end of stimulation relative to sham (p = 0.0009, corrected). The reduction in right hemispheric PC-PHG LPS was significantly correlated with negative symptom improvement at the end of the stimulation (r = 0.503, p = 0.039). Our findings suggest that in-phase theta-tACS can modulate theta-band large-scale functional connectivity pertaining to negative symptoms. Considering the failure of right hemispheric PC-PHG functional connectivity to predict improvement in negative symptoms at one-week follow-up, future studies should investigate whether it can serve as a surrogate of treatment response to theta-tACS.

High-Frequency Transcranial Random Noise Stimulation Modulates Gamma-Band EEG Source-Based Large-Scale Functional Network Connectivity in Patients with Schizophrenia: A Randomized, Double-Blind, Sham-Controlled Clinical Trial

Schizophrenia is associated with increased resting-state large-scale functional network connectivity in the gamma frequency. High-frequency transcranial random noise stimulation (hf-tRNS) modulates gamma-band endogenous neural oscillations in healthy individuals through the application of low-amplitude electrical noises. Yet, it is unclear if hf-tRNS can modulate gamma-band functional connectivity in patients with schizophrenia. We performed a randomized, double-blind, sham-controlled clinical trial to contrast hf-tRNS (N = 17) and sham stimulation (N = 18) for treating negative symptoms in 35 schizophrenia patients. Short continuous currents without neuromodulatory effects were applied in the sham group to mimic real-stimulation sensations. We used electroencephalography to investigate if a five-day, twice-daily hf-tRNS protocol modulates gamma-band (33-45 Hz) functional network connectivity in schizophrenia. Exact low resolution electromagnetic tomography (eLORETA) was used to compute intra-cortical activity from regions within the default mode network (DMN) and fronto-parietal network (FPN), and functional connectivity was computed using lagged phase synchronization. We found that hf-tRNS reduced gamma-band within-DMN and within-FPN connectivity at the end of stimulation relative to sham stimulation. A trend was obtained between the change in within-FPN functional connectivity from baseline to the end of stimulation and the improvement of negative symptoms at the one-month follow-up (r = -0.49, p = 0.055). Together, our findings suggest that hf-tRNS has potential as a network-level approach to modulate large-scale functional network connectivity pertaining to negative symptoms of schizophrenia.

[Clinical study on the relationship between the exosomes in bronchoalveolar lavage fluid and plasma and the severity of lung injury and outcome in early acute respiratory distress syndrome patients]

Objective: To investigate the relationship between the levels of exosomes in bronchoalveolar lavage fluid (BALF) and plasma and the severity of lung injury and its outcome in patients with acute respiratory distress syndrome (ARDS). Methods: Patients who were admitted to the Department of Critical Care Medicine, Zhongda Hospital Affiliated to Southeast University and received invasive mechanical ventilation were selected from August 2020 to April 2021, and they were divided into ARDS group and non-ARDS group. Finally, 33 ARDS patients were included, including 18 males and 15 females, aged (65.5±15.5) years; 10 non-ARDS patients, 8 males and 2 females, aged (57.2±15.3) years. The BALF and plasma of the two groups of patients were collected within 24 hours after enrollment, and the total exosomes of the samples were collected by ultracentrifugation. Nanoparticle tracking analysis (NTA) was used to detect and compare the differences in exosome content between the two groups. Correlation of content with the severity and prognosis of lung injury in ARDS patients. Results: There was no significant difference in gender and age between ARDS group and non-ARDS group (both P>0.05). The exosome in plasma of ARDS group was significantly higher than that of non-ARDS group [(25.3±1.2)/ml vs (24.2±1.6)/ml, P=0.031], while the exosomes in BALF of ARDS group was also higher than that of non-ARDS group [(26.5±1.6)/ml vs (24.6±1.1)/ml, P=0.001]. The exosomes in BALF of patients with ARDS caused by intrapulmonary causes was higher than that in ARDS group caused by extrapulmonary causes [(26.9±1.5)/ml vs (25.2±0.9)/ml, P=0.01], and the infection caused by bacterial shows that the highest exosome level in BALF. The exosomes in the BALF of the mild ARDS group was significantly lower than that of the severe ARDS group [(25.7±1.3)/ml vs (27.2±1.5)/ml, P=0.038]; the exosomes in BALF of ARDS patients was negatively correlated with P/F ratio (r=-0.38, P=0.03); and it was positively correlated with Murray lung injury score (r=0.47, P=0.01). However, the static compliance levels, length of hospital stay, duration of mechanical ventilation, and 28-day outcome were not associated with the exosomes in BALF. Conclusion: Compared with non-ARDS patients, ARDS patients have significantly higher levels of exosomes in BALF and plasma, there is a certain correlation between exosomes derived from BALF and the severity of lung injury in ARDS.

[Long-term mesh-related complications after total pelvic reconstruction surgery with tension-free transvaginal mesh]

Objective: To investigate the long-term mesh-related complications and treatment outcome of total pelvic reconstruction surgery with tension-free transvaginal mesh (PROSIMA^TM pelvic floor repair system). Methods: From July 2010 to June 2012, 48 patients with severe pelvic organ prolapse(POP)who underwent PROSIMA^TM were enrolled and treated in Peking Union Medical College Hospital. 29 patients (60.4%) were followed up periodically for at least 3 years to observe the occurrence of long-term mesh-related complications, and the clinical characteristics, classification of complications and treatment outcome of these cases were summarized. Results: The 29 cases with an average age of (65.1±5.2) years were followed up for an average of (71.6±21.2) months. The last follow-up was 36-105 months after treatment. The long-term success rate of the treatment was 79.3% (n=23). There were 18 cases of mesh exposure (18/48, 37.5%), of which 10 cases (55.6%) were new and persistent. 4 cases (4/18) had symptoms; the rest were found by pelvic examination. Ten patients (10/18) were positive for vaginal swab culture. As for treatment outcome, one case suffered from mesh erosion into the bladder. 4 patients (6.9%) complained of postoperative pain. Twenty-nine patients were divided into the exposure group (n=18) and the non-exposure group (n=11) according to mesh exposure occurrence. There was a significant difference in the proportion of positive swab culture results between the two groups (P=0.019), but no significant difference in the incidence of postoperative pain (P=0.566). Conclusion: The incidence of long-term mesh exposure in PROSIMA^TM is not low, and most of patients with which had no symptoms.

[Effect of the pessary treatment on anxiety disorder in patients with symptomatic pelvic organ prolapse]

Objective: To evaluate the effect of the pessary treatment on general anxiety disorder in patients with symptomatic pelvic organ prolapse (POP). Methods: Between December 2018 and January 2020, 213 patients who received the pessary treatment for symptomatic POP in the Peking Union Medical College Hospital (PUMCH) were enrolled in this prospective observational study. Accepting the pessary successfully means that the patient keeping the pessary for 2 weeks were satisfied with it and willing to use it afterwards, or means that the patient having changed a new pessary and keeping it for 2 weeks were satisfied with it and willing to use it afterwards. The questionnaire General Anxiety Disorder-7 (GAD-7) was used to assess the anxiety state of POP patients, including 163 patients who accepted the pessary treatment successfully and 50 patients who failed, before and after the pessary treatment. A score of 10 or more was considered as the moderate or severe anxiety and defined as the anxiety disorder. Patients who accepted the pessary treatment successfully were followed up for 3 months. Results: Before the treatment, the prevalence of anxiety disorders was 20.9% (34 out of 163) for those patients accepting the pessary and that was 20.0% (10 out of 50) for those patients who failed in keeping the pessary, the difference of which were not statistically significant (P=0.896). The difference of demographic data and clinical characteristics between the anxiety disorder group and the non-anxiety disorder group were not statistically significant (P>0.05). After 3 months of the pessary treatment for those patients using the pessary treatment, the prevalence of anxiety disorders dropped to 3.7% (6/163) from 20.9% (P<0.001). The GAD-7 score of patients with anxiety disorders decreased from a median of 16.0 (12.5, 21.0) before the treatment to 1.0 (0, 4.0) after the treatment, and the difference was statistically significant (P<0.001). Conclusion: Around 20% POP patients receiving pessary treatment had the moderate or severe general anxiety disorder. After 3 months of using the pessary treatment, the prevalence of anxiety disorders in POP patients had dropped significantly.

A higher degree of insight impairment in stabilized schizophrenia patients is associated with reduced cardiac vagal tone as indexed by resting-state high-frequency heart rate variability

Varying degrees of impaired clinical insight in schizophrenia differentially impact medication adherence and clinical outcomes, prompting in-depth investigations of the deficits. Research is scarce on the differences in peripheral physiological markers between varying degrees of impaired insight. The aims of this study were to examine the differences in (1) resting-state high-frequency heart rate variability (HF-HRV) and (2) crucial clinical outcomes between schizophrenia patients with varying degrees of insight impairment as measured by the Positive and Negative Syndrome Scale (PANSS) item G12 (lack of judgment and insight). The study recruited a sample of 95 stabilized schizophrenia patients with insight impairment. Patients were divided into 2 groups of either minimal insight impairment (n = 25, PANSS G12 = 2-3) or moderate-to-severe insight impairment (n = 70, PANSS G12 ≥ 4). Patients with moderate-to-severe insight impairment displayed lower HF-HRV, clinician-rated psychosocial function, medication adherence, and working memory capacity, and higher self-reported psychosocial function and life quality, but comparable cognitive insight compared to those with minimal insight impairment. A logistic regression model predicted moderate-to-severe insight impairment based on HF-HRV values at the optimal cut-off point of 3.655, with the sensitivity and specificity 84% and 72%, respectively. HF-HRV seems a peripheral marker sensitively reflecting central pathophysiology implicated in insight impairment of schizophrenia.

[Application of diffusion tensor imaging combined with virtual reality three-dimensional reconstruction in the operation of gliomas involved eloquent regions]

OBJECTIVE

To investigate the values of diffusion tensor imaging (DTI) and virtual reality (VR) techniques in design surgery program of gliomas near eloquent regions.

METHODS

In this study, 35 cases were retrospectively analyzed with gliomas involved language areas or rolandic regions operated in Department of Neurosurgery, Peking University Third Hospital from January 2015 to January 2019. Surgery programs were performed by Dextroscope virtual reality system. The pre-operative data, such as the magnetic resonance imaging (MRI), magnetic resonance arteriography (MRA) and DTI was transferred into the VR computer for restitution,Tumors, neural fiber tracts and blood vessels were reconstructed to simulate operation and design individual surgical plan. Neurological function was evaluated 1 week, 1 month and 3 months after operation.

RESULTS

Virtual reality three-dimensional images of the 35 cases were successfully achieved, including neural fiber tracts,blood vessels and the lesions. The displacement and destruction of fiber tracts, the anatomic relationship between tumor and important fiber bundle, artery and vein could be shown clearly. Surgical simulation and surgery program of VR of the 35 patients were successfully performed. The 3D images obtained from virtual reality near to the real surgery. Ten of the 35 cases were defined as rolandic regions tumors, 14 of the 35 cases were defined as language areas tumors and 11 of the 35 cases involved both language areas and rolandic regions. Complete resection of enhancing tumor (CRET) was achieved in 30 cases (85.7%), subtotal resection in 5 cases (14.3%), neurological function improved in 34 cases (97.1%) after operation,and 1 case had no improvement compared with that before(2.9%). Thirteen cases without neurological deficit pre-operation, showed transient neurological deficit ,which were recovered about 10 days post-operation, 12 of 22 cases with pre-operative neurologic deficit, improved one week postoperation, 9 of 22 cases with pre-operative neurologic deficit improved one month after operation, the rest 1 case was recurrent with glioblastoma with aggravated hemiplegia symptom after operation, who died of cerebral hernia 2 months later.

CONCLUSION

Dextroscope virtual reality system can clearly expose and quantify the 3D anatomic relationship of tumors, neural fiber tracts and blood vessels surrounding gliomas near eloquent regions, which is helpful to design the best individualized surgery program, to improve surgical effect.

[Early surgical treatment of multi-segmet intramedullary cervical spinal cord ependymoma]

OBJECTIVE

To investigate the early clinical treatment and prognosis of multi-segment intramedullary cervical ependymoma.

METHODS

Twenty patients with multi-segment (more than 3 segments) intramedullary spinal ependymoma (McCormic grade I) were microsurgically treated with assistance of intraoperative neuroelectrophysiological monitoring. None of them received postoperative radiotherapy. Preoperatively all the patients underwent MRI examination and their neurologically function was assessed by McCormic classification method. They were followed up for an average of 2.7 years (The follow-up ranged from 3 months to 4 years). All the patients underwent review of the MRI examination and their postoperative neurological function was assessed by McCormic classification method again. Evaluation was accomplished according to the results of the follow-up.

RESULTS

All tumors were intramedullary. The length of the tumor body varied from 3 to 8 vertebral segments with an average of 4.2 vertebral segments. Gross total removal was achieved in all the 20 patients through one-stage operation. The pathology of these patients was ependymoma (WHO grades I to II ). Two cases were lost during the follow-up due to the change of contact, but the hospital records of them showed that they recovered well at discharge. Eighteen cases were followed up constantly after operation. A case which ran through the whole cervical spinal cord had short-term mild motor dysfunction after operation, which manifested as weakness of the left side muscle strength to grade IV (which recovered to grade V during the follow-up period). Results of the follow-up showed that these 18 patients recovered well. Preoperative symptoms, such as limb numbness and painness were significantly alleviated. There was no obvious motor dysfunction. The bowel and bladder function of these 18 patients were almost normal. The McCormic scores of these 18 patients remained in grade I. No recurrence was found on review of the MRI examination. The main complications were a certain degree of deep sensory disturbance of lower extremities. The operation did not significantly affect the patient's life and work.

CONCLUSION

Aggressive surgical therapy is a good treatment strategy for early multi-segment intramedullary cervical ependymoma. There is nearly no recurrence after operation and no postoperative radiotherapy is needed after gross total removal of tumors.

Surgical and Functional Outcomes Following Buried Penis Repair With Limited Panniculectomy and Split-thickness Skin Graft

OBJECTIVE

To report surgical and functional outcomes of buried penis surgery.

METHODS

Outcomes following buried penis surgery at the University of Washington were assessed from June 1, 2005 to June 1, 2016. Patient demographic and surgical data were abstracted from a retrospective chart review. All patients were attempted to be contacted by phone for long-term follow-up. Uni- and multivariate analysis was performed to evaluate for association with any complication.

RESULTS

A total of 42 men underwent buried penis repair surgery (mean short-term follow-up 8.1 months). There was an overall 33% 90-day complication rate (21 events). In univariate analysis, body mass index (BMI; P = .02) and no history of gastric bypass (P = .03) were significant predictors of any complication. In multivariate analysis, only BMI remained significant (odds ratio 1.1 for each increase in unit of BMI, 95% confidence interval 1.01-1.27). Twenty-seven patients were reached for long-term follow-up (mean 39 months). Patients reported improvements in every functional domain that was assessed. Of the patients, 85% reported they would undergo buried penis surgery again, 74% that surgery led to a positive change in their lives, and 85% that the surgery had remained a long-term success.

CONCLUSION

Surgical correction of buried penis with penile split-thickness skin graft and limited panniculectomy is well tolerated and results in functional, long-term improvements. BMI is associated with an increased likelihood of a complication following surgery.

[Proton nuclear magnetic resonance spectroscopy recognition of metabolic patterns in fecal extracts for early diagnosis of colorectal cancer]

Objective: To characterize the metabolic " fingerprint" of fecal extracts for diagnosis of early-stage colorectal cancer(CRC)using proton nuclear magnetic resonance spectroscopy(¹H-NMR)-based metabolomics coupled with pattern recognition. Methods: From January 2014 to December 2014, we collected fecal samples at the Second Affiliated Hospital of Shantou University Medical College, from 25 patients with colorectal adenomas(CR-Ad), 20 with stage Ⅰ/Ⅱ CRC, and 32 healthy controls(HCs). The patients were diagnosed by histopathology. No subjects had any complicating diseases. HCs showed no abnormalities from blood tests, endoscopic examination, diagnostic imaging, and/or medical interviews. We excluded participants who used antibiotics, NSAIDS, statins, or probiotics within two months of study participation, and any patients who underwent chemotherapy or radiation treatments prior to surgery. We used orthogonal partial least-squares-discriminant analysis(OPLS-DA)for pattern recognition(dimension reduction)on ¹H-NMR processed data(¹H frequency of 400.13 MHz), to find metabolic differences among CR-Ad, carcinoma and HC fecal samples; and receiver operating characteristic(ROC)analysis to determine the diagnostic value of the fecal metabolic biomarkers. Results: Fecal samples were collected from 20 patients with Stage Ⅰ/Ⅱ CRC(11 M, 9 F, median age(52±13)years), 25 with CR-Ad(14 M, 11 F, median age(53 ± 11)years)and 32 HCs(15 M, 17 F, median age(53 ± 14)years). OPLS-DA clearly distinguished CR-Ad and stage Ⅰ/Ⅱ CRC from HC samples, based on their metabolomic profiles. Relative signal intensities in HCs were significantly lower than in the cancer patients for butyrate(HC: 23.0±6.0; CR-Ad: 18.0±5.0; CRC: 14.0±6.0; Z=-2.07, P=0.008), acetate(HC: 45.0±11.0; CR-Ad: 31.0±11.0; CRC: 24.0±8.0; Z=- 2.32, P=0.011), propionate(HC: 26.0 ± 7.0; CR-Ad: 22.0 ± 6.0; CRC: 19.0 ± 5.0; Z=- 2.43, P=0.032), glucose(HC: 37.0±7.0; CR-Ad: 31.0±7.0; CRC: 26.0±8.0; Z=-2.07, P=0.044)and glutamine(HC: 4.5±2.0; CR-Ad: 4.9 ± 1.0; CRC: 5.4 ± 1.0; Z=2.21, P=0.044). However, relative signal intensities in HCs were significantly higher than in patients for lactate(HC: 4.8±1.0; CR-Ad: 6.9±2.0; CRC: 4.8± 1.0; Z=2.02, P= 0.038), glutamate(HC: 3.2 ± 2.0; CR-Ad: 4.9 ± 1.0; CRC: 3.2 ± 2.0; Z=2.21, P=0.044)and succinate(HC: 12.0±2.0; CR-Ad: 15.0±3.0; CRC: 12.0± 2.0; Z=2.25, P=0.011). Among the potential biomarkers, acetate at 1.92 ppm, and succinate at 2.41 ppm displayed relatively high area under ROC, with sensitivity and specificity both >90%, to distinguish early-stage CRC patients from HCs. Conclusion: Fecal metabolic profiles distinguish of HCs from patients with CRC patients, even in the early stages(stage Ⅰ/Ⅱ), highlighting the potential of NMR-based fecal metabolomic fingerprinting as tools for early CRC diagnosis.

Surgical management of primary non-small-cell carcinoma of lung with synchronous solitary brain metastasis: local experience

OBJECTIVE

To report the surgical experience in the management of patients with synchronous primary lung cancer and solitary brain metastasis.

DESIGN

Retrospective cohort study.

SETTING

Regional hospital, Hong Kong.

PATIENTS

Seventeen patients with synchronous primary lung cancer and solitary brain metastasis were treated by pulmonary resection and neurosurgical intervention between 1994 and 2007.

RESULTS

Median patient survival was 52 months (95% confidence interval, 9-95 months) and the 5-year survival was 27%. The univariate analysis yielded no significant prognostic factor. Four out of six patients who had lymph node metastases developed tumour recurrence.

CONCLUSION

In view of encouraging survival results, aggressive therapy including pulmonary resection and neurosurgical intervention should be recommended for patients with synchronous presentation with primary lung cancer and solitary brain metastasis.

Trans-phonon effects in ultra-fast nanodevices

We report a novel phenomenon in carbon nanotube based ultra-fast mechanical devices, the trans-phonon effect, which resembles the transonic effects in aerodynamics. It is caused by dissipative resonance of nanotube phonons similar to the radial breathing mode, and subsequent drastic surge of the dragging force on the sliding tube, and multiple phonon barriers are encountered as the intertube sliding velocity reaches critical values. It is found that the trans-phonon effects can be tuned by applying geometric constraints or varying chirality combinations of the nanotubes.

The short-to-midterm results of endovascular stent grafting for acute thoracic aortic diseases in Chinese patients

OBJECTIVE

To review the results of endovascular treatment of acute thoracic aortic diseases in a group of Chinese patients.

DESIGN

Retrospective study.

SETTING

A tertiary referral hospital with a cardiothoracic surgery service.

PATIENTS

All 15 patients presenting with acute thoracic aortic diseases between September 2001 and October 2005 inclusive, of whom eight had traumatic rupture, four had complicated acute dissections, two had mycotic aneurysms, and one an aneurysm with an aortobronchial fistula.

INTERVENTIONS

Thoracic aortic stent grafting.

MAIN OUTCOME MEASURES

Immediate success, 6-month and 1-year survival rates.

RESULTS

The median follow-up period was 20.6 months (range, 0-50.1 months). Stent grafts were deployed with immediate success in all patients. Two patients had ancillary bypass surgery for the supra-aortic branches. There were two in-hospital deaths. Four sustained access artery injury and needed graft repair. Computed tomography at 1 month showed complete thrombosis of the aneurysmal lumen or the thoracic aortic false lumen in 12 of 13 survivors. Computed tomography at 6 months showed complete thrombosis of the aneurysmal lumen or the false lumen in nine of 10 patients due for follow-up. Both 6-month and 1-year survival rates were 87%.

CONCLUSIONS

Thoracic aortic stent grafting for acute thoracic aortic disease is feasible and has a high success rate, with good short-to-midterm results. However, the large size of the stent graft introducer set imposes a high risk of access artery injury, for which further improvements are necessary.

Benign metastasising leiomyoma: a rare but possible cause of bilateral pulmonary nodules in Chinese patients

We report three cases of benign metastasising leiomyoma, which is a rare cause of multiple lung nodules, in three Hong Kong Chinese females. One patient presented with pleuritic chest pain, another was asymptomatic, while the last presented with haemoptysis. All three patients had previously undergone surgical resection of uterine leiomyomas. Multiple lung nodules mimicking lung metastases were demonstrated on chest radiographs, and all three diagnoses were obtained from lung biopsies. Hormonal therapy was given to two patients with variable responses. To the best of our knowledge, this is the first report of benign metastasising leiomyoma in Hong Kong Chinese population. It highlights the importance of considering this rare and benign disease in premenopausal females presenting with multiple lung nodules.

Vibration characteristics of composite piezoceramic plates at resonant frequencies: experiments and numerical calculations

The experimental measurement of the resonant frequencies for the piezoceramic material is generally performed by impedance analysis. In this paper, we employ an optical interferometry method called the amplitude-fluctuation electronic speckle pattern interferometry (AF-ESPI) to investigate the vibration characteristics of piezoceramic/aluminum laminated plates. The AF-ESPI is a powerful tool for the full-field, noncontact, and real-time measurement method of surface displacement for vibrating bodies. As compared with the conventional film recording and optical reconstruction procedures used for holographic interferometry, the interferometric fringes of AF-ESPI are produced instantly by a video recording system. Because the clear fringe patterns measured by the AF-ESPI method will be shown only at resonant frequencies, both the resonant frequencies and corresponding vibration mode shapes are obtained experimentally at the same time. Excellent quality of the interferometric fringe patterns for both the in-plane and out-of-plane vibration mode shapes are demonstrated. Two different configurations of piezoceramic/aluminum laminated plates, which exhibit different vibration characteristics because of the polarization direction, are investigated in detail. From experimental results, we find that some of the out-of-plane vibration modes (Type A) with lower resonant frequencies cannot be measured by the impedance analysis; however, all of the vibration modes of piezoceramic/aluminum laminated plates can be obtained by the AF-ESPI method. Finally, the numerical finite element calculations are also performed, and the results are compared with the experimental measurements. Excellent agreements of the resonant frequencies and mode shapes are obtained for both results.

Experimental and numerical investigations of resonant vibration characteristics for piezoceramic plates

Electronic speckle pattern interferometry (ESPI) is a full field, non-contact technique for measuring the surface displacement of a structure subjected to static loading or, especially, to dynamic vibration. In this article we employ an optical system called the amplitude-fluctuation ESPI with out-of-plane and in-plane measurements to investigate the vibration characteristics of piezoceramic plates. Two different configurations of piezoceramic plates, namely the rectangular and the circular plates, are discussed in detail. As compared with the film recording and optical reconstruction procedures used for holographic interferometry, the interferometric fringes of AF-ESPI are produced instantly by a video recording system. Because the clear fringe patterns will be shown only at resonant frequencies, both the resonant frequencies and the corresponding mode shapes are obtained experimentally at the same time by the proposed AF-ESPI method. Excellent quality of the interferometric fringe patterns for both the in-plane and out-of-plane vibration mode shapes is demonstrated. The resonant frequencies of the piezoceramic plates are also measured by the conventional impedance analysis. From experimental results, we find that the out-of-plane vibration modes (type A) with lower resonant frequencies cannot be measured by the impedance analysis and only the in-plane vibration modes (type B) will be shown. However, both the out-of-plane (bending) and in-plane (extensional) vibration modes of piezoceramic plates are obtained by the AF-ESPI method. Finally, the numerical finite element calculations are also performed, and the results are compared with the experimental measurements. It is shown that the numerical calculations and the experimental results agree fairly well for both the resonant frequencies and the mode shapes.

The investigation of three-dimensional vibration for piezoelectric rectangular parallelepipeds using the AF-ESPI method

Electronic speckle pattern interferometry (ESPI) is a powerful tool for the full-field measurement of a deformed body. In this paper, a three-dimensional vibrating block that couples the out-of-plane and in-plane motions is investigated using the amplitude-fluctuation ESPI (AF-ESPI). This method demonstrates the advantages of combining high processing speed, such as in the subtraction method, with high fringe sensitivity, such as in the time-averaged method. The optical system for AF-ESPI is then employed to analyze the volume vibration of piezoelectric material for a rectangular parallelepiped configuration. Based on the fact that fringe patterns measured by the AF-ESPI method appear as a clear picture only at the resonant frequency, both the natural frequencies and the out-of-plane and in-plane vibration mode shapes are successfully obtained in this study. Finally, the impedance analysis as well as the finite element method (FEM) with three-dimensional model are also conducted to compare with the result obtained by AF-ESPI. It is shown that the numerical calculation and the experimental result agree fairly well for both the resonant frequency and the mode shape in three-dimensional configurations.

A pharmacodynamic assessment of the impact of antihypertensive non-adherence on blood pressure control

OBJECTIVES

To evaluate if antihypertensive regimens that conform to present FDA guidelines by maintaining > or = 50% of their peak effect at the end of the dosing interval protect patients during sporadic lapses in adherence.

METHODS

169 patients on monotherapy for high blood pressure underwent electronic adherence monitoring for 3 months. Blood pressures were measured during non-study office visits and were retrieved from automated medical records. Questionnaires were used to obtain other covariate information. The ratio of the dosing interval to the half-life of drug activity (I') was used to capture conformity with FDA guidelines. Data analysis focused on the interaction between I' and the impact on blood pressure of delayed dosing.

RESULTS

The average (+/- standard deviation) blood pressure during the study was 139.0(+/- 12.0)/85.0(+/- 6.9) mm Hg. Lisinopril followed by sustained-release verapamil, atenolol, and hydrochlorothiazide were the most frequently prescribed agents. The majority of regimens (99%) conformed to FDA dosing guidelines. Of the patients 23% missed a dose before their blood pressure check. Non-adherence, however, did not have a direct impact on blood pressure, and no interaction with I' of was detected.

CONCLUSIONS

Among patients with relatively mild hypertension on single-drug therapy, regimens that conform to current FDA dosing guidelines may prevent losses of blood pressure control during episodic lapses of adherence. These findings should be replicated in other patient populations with standardized blood pressure measurement to confirm their validity.

Thoracoscopic major lung resections: an Asian perspective

The application of video-assisted thoracic surgery (VATS) for major lung resection is controversial. We review our combined experience from three centers in Asia. From June 1993 through June 1997, 214 patients underwent VATS major resections (2 segmentectomies, 203 lobectomies, 6 bilobectomies, 3 pneumonectomies), mostly for primary malignancy. Stringent selection criteria were used to choose patients for this approach. We prefer a technique of not spreading ribs, using conventional thoracic instrument for dissection and routine use of wound protector for specimen retrieval. There was one postoperative surgical death and 47 non-fatal complications, which compare favorably with published series on open technique. Of the primary lung cancer patients, 93% are still alive after a mean follow-up of 26 months. We conclude that VATS major lung resection is technically feasible in selected patients and associated with favorable intermediate-term results.

Thoracoscopic lobectomy for benign diseases

The few reports in the literature on thoracoscopic anatomic lung resections were almost exclusively for early primary lung cancers. We report our combined experience on video-assisted thoracoscopic (VAT) lobectomy for benign diseases from two major hospitals in Hong Kong over a 20-month period. From August 1993 to March 1995, 66 VAT lobectomies were performed; of this number, 10 cases (15%) were for benign diseases (5 tuberculosis, 2 organized pneumonia, 1 bronchiectasis, 1 sclerosing hemangioma, 1 infected bronchogenic cyst). There was no mortality or incidence of intraoperative complications. Postoperative complications occurred in one patient with tuberculosis and consisted of persistent air leak and subsequent wound infection. There were no long-term complications after a mean follow-up of 11 months. The mean duration of chest tube drainage was 6.7 days and that of hospital stay was 9.8 days. These results were not statistically different from those achieved in VAT lobectomies performed for malignant tumors (5.0 days for drainage and 6.8 days for hospital stay) despite the fact that hilar dissection was sometimes more difficult in the former because of inflammatory changes. We conclude that VAT lobectomy for benign diseases is technically feasible even though its role in thoracic surgery remains to be defined.

Video-assisted thoracoscopic anatomic lung resections. The initial Hong Kong experience

We report our combined experience on video-assisted thoracoscopic (VAT) anatomic lung resections from two major hospitals in Hong Kong over a 17-month period. From August 1993 to December 1994, 82 cases of major lung resections were attempted using the VATS approach, of which 60 were successfully completed (55 lobectomies, 2 bilobectomies, 2 pneumonectomies, and 1 segmentectomy). Of these 60 cases, there were 43 men and 17 women with a mean age of 66 years (range, 37 to 85 years). The final pathologies were 52 primary lung cancers (37 adenocarcinoma, 11 squamous cell carcinoma, 2 bronchoalveolar carcinoma, 1 adenosquamous carcinoma, and 1 undifferentiated carcinoma); 1 pulmonary metastasis (from nasopharyngeal carcinoma); and 7 benign lesions (3 tuberculosis, 1 bronchiectasis, 1 sclerosing hemangioma, 2 organizing pneumonia). There was one postoperative death (mortality rate, 1.8%). Complications include persistent air leak over 10 days (four), wound infection (two), supraventricular tachycardia (three), and recurrence of tumor over the utility thoracotomy scar (one). All the patients were followed up from 8 weeks to 19 months (mean, 10 months). The mean duration of chest drainage was 5.4 days (range, 2 to 25 days). The mean hospital stay was 7.2 days (range, 4 to 35 days). The average postoperative parenteral narcotic (meperidine hydrochloride [Pethidine]) requirement by patient-controlled analgesia was 275 mg (range, 75 to 800 mg). This compared favorably with an age- and sex-matched historic group of patients who underwent posterolateral thoracotomy and had a hospital stay of 10.4 days (statistically non-significant) and narcotic requirement of 950 mg (statistically significant by paired t test). We conclude that VAT anatomic lung resection is technically feasible. However, there are some specific complications associated with major lung resection through minimal access. Refinement of our present technique and attention to details are important to improve our results.

Distinct mutational spectrum of the p53 gene in lung cancers from Chinese women in Hong Kong

Accumulating evidence suggests that the p53 gene is a good target for molecular epidemiological studies to search for risk factors in carcinogenic events. The lung cancer incidence for females in Hong Kong is unusually high, ranking among the highest in the world despite a low percentage with a history of smoking. To gain insights into possible etiological risk factors responsible for this high incidence, we examined p53 mutations in 35 lung cancer specimens from Chinese females living in Hong Kong and compared them with 35 matched cases from Japanese women as well as previously reported p53 mutations in the world literature. p53 mutations in exons 5-8 were present in 20 and 31% of the Hong Kong and Japanese cases, respectively. Notably, single-base deletions within runs of identical bases were observed in 3 (43%) of the 7 mutations in the Hong Kong cases, in contrast to the absence of such mutations in the controls and the extreme scarcity in the literature, suggesting that distinct environmental and/or genetic factor(s) might be involved. Although the frequent occurrence of characteristic single-base deletions could be a reflection of mutator mutations leading to inefficient mismatch repair of slipped strand mispairings, none of the lung cancer specimens exhibited such microsatellite instabilities.

Primary lymphoepithelioma-like carcinoma of the lung. A clinicopathologic study of 11 cases

BACKGROUND

Lymphoepithelioma-like carcinoma (LELC), best known to occur in the nasopharynx, can arise in a variety of sites, such as the salivary gland, thymus, lung, stomach, and skin. Primary LELC of the lung is very rare, with only limited information in the literature.

METHODS

The clinicopathologic features of 11 patients with pulmonary LELC collected from two regional hospitals in Hong Kong are described.

RESULTS

The patients, all Chinese, were aged 38 to 73 years (median, 54 years), with equal sex incidence. Two of the 8 patients were smokers. Four presented with coin lesions incidentally discovered on chest X-ray, five with cough and blood-stained sputum, and two with pleural effusion. The tumor formed a discrete (9 patients) or an ill-defined (1 patient) nodule in the lung, or, rarely, showed extensive bilateral pulmonary involvement (1 patient). The major bronchi were not involved except in 1 patient. Three patients had lymph node metastasis at presentation; two of them had bone metastasis, one at presentation and one after 9 months. The tumors had pushing margins, and grew in the form of anastomosing islands and sheets, comprising syncytial-appearing large cells with vesicular nuclei and prominent nucleoli. They were infiltrated by an appreciable number of small lymphocytes and plasma cells. Intratumoral amyloid globules were found in one tumor. In five patients, the tumor showed intraepithelial growth within the small bronchi; this could represent either the in-situ phase of the tumor or pagetoid spread into the bronchial epithelium. The neoplastic cells of all patients harbored Epstein-Barr virus (EBV) as demonstrated by in situ hybridization for EBV-encoded small nuclear RNAs. All eight Asian patients with pulmonary LELC previously reported in the literature similarly have been EBV-positive, whereas the four reported Caucasian patients all have been EBV-negative.

CONCLUSION

Lymphoepithelioma-like carcinoma of lung occurring in Asians is an EBV-associated neoplasm; it also appears to occur at a higher frequency in Asians than Caucasians. It usually presents as a solitary subpleural nodule, and there is no strong association with cigarette smoking. Most patients have early stage disease at presentation. From the limited available data, the behavior of LELC of lung is highly variable, ranging from apparent curability by excision (particularly for localized disease) to highly aggressive, extensive disease at presentation.

[The efficacy of sonic and ultrasonic appliances on root canal debridement]

The purpose of this study was to compare the debridement efficacy of hand, sonic (MM-3000), and ultrasonic (Cavi-Endo) appliances, utilizing the same K-type files and a constant flow irrigation system, in the mesial root canals of extracted human mandibular 1st and 2nd molars. Only those roots with a canal curvature of between 10 and 30 degrees, by Schneider's method, were used in this study. The instrumentation time per mesial root canal for each treatment group was also evaluated. Following canal preparation and histological processing, the middle and apical cross-sections were examined to determine the percentage of canal and isthmus cleanliness, and the percentage of planed canal walls in the main canal area. Statistical analysis indicated no significant difference in canal and isthmus cleanliness at the middle and apical levels. All techniques achieved a high level of canal cleanliness. However, step-back hand instrumentation had the greatest percentage of planed canal walls in the main canal area at every portion of the root. Sonic instrumentation, in this study, was significantly faster than hand instrumentation in preparing the root canal system.