PubMed Health⌕ Search

Biomedical subjects

Feng Ling

Publications and source records attributed to Feng Ling.

35 records · Page 2Linked to original sources
PubMed2004

[Aging study of event-related potential on visual spatial attention precued by Chinese words].

OBJECTIVE: Based on the visual experimental paradigm "precue-target", the search range should be affected by different Chinese characters and the dynamic mechanisms of aging in the brain on the visual attention were investigated. METHOD: 16 young and 16 old subjects participated the experiment. Cue was comprised of three Chinese words "Large", or "Median" or "Small." The letter "T" was designed as the target stimulus. When the cue was the "large", "T" may appear within 3 circles. When the cue was the "median", "T" may appear within either the median and small circles. When the cue was small, the target "T" may appear only within the small circle. RESULT: The reaction time (RT) of the two groups of subjects became quick with the reduction of the cue size, while amplitudes of the P1 and N1 component of ERPs increased with the decrease of the cue scale. Old subjects showed longer RT than younger subjects did. The posterior P1 was enhanced significantly and the N1 was inhibited obviously in the old group. The P2 was manifested as significantly inhibitory effect not only in the amplitude but also in the abnormal and unstable waveform. CONCLUSION: The cognitive function of elderly subjects declined in the task of visual spatial attention. We demonstrated for the first time that the P2 was manifested as significantly inhibitory effect, which suggested that the age-related reduction could lead to dysfunction in the anterior scalp to visual spatial attention (voluntary attention).

Adult↗
PubMed2004

[Expression of pituitary tumor transforming gene, endostatin, and basic fibroblast growth factor mRNAs in invasive pituitary adenomas].

OBJECTIVE: To investigate the effect of the expression of pituitary tumor transforming gene (PTTG), endostatin and basic fibroblast growth factor (bFGF) in invasive pituitary adenomas. METHODS: Reverse transcription-polymerase chain reaction (RT-PCR) was used to detect the expression of PTTG, endostatin, and bFGF mRNA in invasive and non-invasive pituitary adenomas. RESULTS: The expression of PTTG and bFGF significantly increased in the invasive pituitary adenomas (all P < 0.01) compared with those in the non-invasive pituitary adenomas. However, the expression of endostatin significantly decreased in the invasive pituitary adenomas compared with the non-invasive pituitary adenomas (P < 0.01). CONCLUSION: Increased expression of human PTTG and bFGF, and decreased expression of endostatin may be related to the genesis of tumor invasiveness. The feasible mechanism may be related to that the increased expression of PTTG plays a role in pituitary tumor invasiveness by altering the balance of tumor angiogenesis.

Adenoma↗
PubMed2003

Mhr1p-dependent concatemeric mitochondrial DNA formation for generating yeast mitochondrial homoplasmic cells.

Mitochondria carry many copies of mitochondrial DNA (mtDNA), but mt-alleles quickly segregate during mitotic growth through unknown mechanisms. Consequently, all mtDNA copies are often genetically homogeneous within each individual ("homoplasmic"). Our previous study suggested that tandem multimers ("concatemers") formed mainly by the Mhr1p (a yeast nuclear gene-encoded mtDNA-recombination protein)-dependent pathway are required for mtDNA partitioning into buds with concomitant monomerization. The transmission of a few randomly selected clones (as concatemers) of mtDNA into buds is a possible mechanism to establish homoplasmy. The current study provides evidence for this hypothesis as follows: the overexpression of MHR1 accelerates mt-allele-segregation in growing heteroplasmic zygotes, and mhr1-1 (recombination-deficient) causes its delay. The mt-allele-segregation rate correlates with the abundance of concatemers, which depends on Mhr1p. In G1-arrested cells, concatemeric mtDNA was labeled by [14C]thymidine at a much higher density than monomers, indicating concatemers as the immediate products of mtDNA replication, most likely in a rolling circle mode. After releasing the G1 arrest in the absence of [14C]thymidine, the monomers as the major species in growing buds of dividing cells bear a similar density of 14C as the concatemers in the mother cells, indicating that the concatemers in mother cells are the precursors of the monomers in buds.

DNA, Concatenated↗
PubMed2003

[Complications of stent-assistant angioplasty of symptomatic intracranial artery stenosis].

OBJECTIVE: To discuss the safety of intracranial stenting for refractory symptomatic intracranial artery stenosis. METHODS: Forty-eight patients with symptomatic intracranial artery stenosis were treated by transluminal stent-assistant angioplasty. Of them, 40 cases were selected because they had recurrent TIAs or mild stroke despite of antiplatelet or anticoagulation therapy; 8 cases with high-grade stenosis after acute cerebral artery theromblysis. Lesions involved MCA (17/48); Basilar artery (8/48); intracranial vertebral artery (18/18); and distal ICA (5/18). RESULTS: For 46 of 48 cases the flexible coronary stent were successfully deployed. The average stenosis reduced from 83% to 5%, short-term follow-up showed good clinical improvement. Complications include vessel rupture (1/18); acute thrombosis within stent (1/48); perforation of cortical artery (1/18) and perforate vessel occlusion (1/18). CONCLUSION: Stent-assistant angioplasty are effective for treatment of symptomatic intracranial stenosis, the higher rate of complications may be because of the limited experiences of this technique. it need further practise and long term follow-up study.

Adult↗
PubMed2003

[Combined intraarterial thrombolysis and intra-cerebral stent for acute ischemic stroke institute of brain vascular diseases].

OBJECTIVE: To test feasibility, safety and efficacy of combined intraarterial thrombolysis and intra-cerebral stent for acute ischemic stroke. METHODS: From 2001-5 to 2002-8, 19 patients with acute onset of stroke were treated with intraaterial thrombolysis followed by intra-cerebral stent. 9 located in middle cerebral artery (MCA), 10 located in basal artery (BA). For each patient, intraarterial thrombolysis of MCA or BA was applied at first, stent angioplasty was applied at the stenosis left after the thrombolysis by using the stent for coronary artery. RESULTS: All the 19 patients left stenosis after intraaterial thrombolysis, and the average stenosis was 85% in diameter. After the operation of stent, the images showed the vascular is smooth and had no stenosis left. The symptoms were disappeared or improved. Thrombus formation in the stent occurred on 1 patient 24 hours after the operation. TIA never occurred in the left 18 patients then. TCD follow up showed blood flow is normal. CONCLUSIONS: It is feasibility of intraaterial thrombosis followed by intra-cerebral stent. And it is valid for preventing occlusion again of the vessel and decreasing the rate of TIA occurring.

Acute Disease↗
PubMed2003

[Diagnosis and treatment of spinal dural arteriovenous fistulas: 110 cases report].

OBJECTIVE: To discuss the diagnosis, treatment and prognosis of spinal dural arteriovenous fistulas (SDAVF). METHODS: The clinical and following-up date from 110 patients with SDAVF diagnosed by spinal MRI and spinal angiography were analyzed retrospectively. RESULTS: Draining vein between fistula and spinal cord was interrupted by laminectomy approach as first choice in 61 patients, by hemi-laminectomy approach in 37, and by endovascular embolization in 12, and re-operation due to recurrence after embolization in 3. Anticoagulation, hydration and early rehabilitation were used postoperatively. Complete disappearance of SDAVF was confirmed in all 106 patients who received postoperative spinal angiography. The para-medullary tortuous flow voids fully disappeared in 74 patients and partly disappeared in 15 on postoperative T(2)-weighted MRI. Follow up of 98 patients showed complete recovery in 54 patients, improvement in 34, and no change in 10. Three of the 10 patients were reoperated on because of recurrence 1 to 5 years after embolization. CONCLUSIONS: SDAVF can produce good outcome after early diagnosis and treatment. Interruption of the draining vein between fistula and spinal cord by hemi-laminectomy approach is the first choice for the treatment of SDAVF.

Adult↗
PubMed2003

Direct intratumoral embolization of hypervascular tumors of the head and neck.

OBJECTIVE: To evaluate a devascularization technique for hypervascular tumors of the head and neck by direct intratumoral puncture. METHODS: Six cases of hypervascular tumor of the head and neck were reviewed, focusing on findings from digital subtraction angiography and preoperative direct intratumoral embolization and their effects after the operation. RESULTS: Total devascularization by complete embolization was achieved in 2 cases: 1 nasopharyngeal angiofibroma and 1 spongiform tumor, both of which were completely excised endoscopically with blood loss of 60 ml. Incomplete devascularization through 80% - 90% embolization was achieved in the other 4 cases: 1 paraganglioma was totally removed with 800 ml of blood loss, 1 hemangioblastoma was not completely excised with 400 ml of blood loss and 2 nasopharyngeal angiofibromas involving the intracranial region were partially eliminated with a total blood loss of 1600 ml. CONCLUSION: The new technique of preoperative embolization of hypervascular tumors of the head and neck by direct intratumoral puncture, which can decrease blood loss during the accompanying tumor resection and increase the possibility of complete tumor removal, is feasible, convenient, safe, and effective.

Adolescent↗
PubMed2003

Initial comparison of intracranial aneurysm embolization with mechanical detachable spirals and with Guglielmi detachable coils.

OBJECTIVE: To compare the embolization effects of intracranial aneurysm with mechanical detachable spirals (MDS) and with Guglielmi detachable coils (GDC). METHODS: One hundred and twenty cases with 125 intracranial aneurysms were embolized in Beijing Hospital from March 1995 to July 1999. Sixty-six aneurysms in 64 cases were embolised with MDS, 51 in 48 with GDC, and 8 in 8 with both MDS and GDC. Clinical data including sex, age, subarachnoid hemorrhage (SAH), Hunt & Hess grading, diameter and neck width of aneurysms, number and length of coils used per aneurysm, occlusive ratio, and complications were compared between MDS and GDC groups. RESULTS: MDS and GDC group were comparable (t-test or chi2-test, all P value > 0.10) in terms of age, sex, diameter of aneurysms [(8.46 +/- 3.42) mm vs. (7.38 +/- 3.45) mm], neck width [(3.49 +/- 1.50) mm vs. (3.26 +/- 1.52) mm], coils number [(4.65 +/- 3.01) vs. (4.24 +/- 2.65)] and their length [(460.2 +/- 398.5) mm vs. (422.9 +/- 387.1) mm] used per aneurysm, occlusive ratio in aneurysms embolized > or = 80% [(95.00% +/- 6.32%) vs. (94.19% +/- 7.63%)], mortality and permanent complications (7.8% vs. 4.2%). CONCLUSIONS: MDS and GDC are all materials for embolization of intracranial aneurysms. MDS is less expensive, but more difficult to control and of propensity to complications while GDC is more compliant, easier to be used, safer, and have many alternative types for use as well a more extensive indications.

Adult↗
PubMed2002

Recombination-dependent mtDNA partitioning: in vivo role of Mhr1p to promote pairing of homologous DNA.

Yeast mhr1-1 was isolated as a defective mutation in mitochondrial DNA (mtDNA) recombination. About half of mhr1-1 cells lose mtDNA during growth at a higher temperature. Here, we show that mhr1-1 exhibits a defect in the partitioning of nascent mtDNA into buds and is a base-substitution mutation in MHR1 encoding a mitochondrial matrix protein. We found that the Mhr1 protein (Mhr1p) has activity to pair single-stranded DNA and homologous double-stranded DNA to form heteroduplex joints in vitro, and that mhr1-1 causes the loss of this activity, indicating its role in homologous mtDNA recombination. While the majority of the mtDNA in the mother cells consists of head-to-tail concatemers, more than half of the mtDNA in the buds exists as genome-sized monomers. The mhr1-1 deltacce1 double mutant cells do not maintain any mtDNA, indicating the strict dependence of mtDNA maintenance on recombination functions. These results suggest a mechanism for mtDNA inheritance similar to that operating in the replication and packaging of phage DNA.

Amino Acid Substitution↗
PubMed2002

[Stent-assisted angioplasty in treatment of symptomatic intracranial artery stenosis].

OBJECTIVE: To investigate the indications, safety and effectiveness of intracranial deployment of stents in treatment of systematic intracranial artery stenosis. METHODS: Stent-assisted angioplasty was performed upon 7 consecutive patients with symptoms of intracranial artery stenosis unresponsive to anticoagulant therapy and antiplatelet therapy. The lesions involved the middle cerebral artery in 3 cases, distal end of internal carotid artery in one case, basilar artery in one case, and intracranial section of vertebral artery in 2 cases. Short-term clinical and angiographic data were obtained. RESULTS: Symptoms of procedure-related intracranial hemorrhage and intracranial haematoma developed later were found in one patient. Emergency craniotomy was performed 5 hours after the stenosis-assisted angioplasty. The remaining patients experienced alleviation of symptoms without transient ischemic attack and apoplexy during the short-term follow-up. Angiography showed that the stenosis degree reduced from 83% to 5%. 0 - 3 months of follow-up by transcranial Doppler showed good patency of stented lesions. CONCLUSION: Stent-assisted angioplasty effectively treats atherosclerotic intracranial stenosis lesions. Long-term follow-up and further clinical/technical research are still needed.

Adult↗
PubMed2002

[Computer aided intracranial aneurysm embolization with GDC].

OBJECTIVE: To establish an expert system that automatically generates optimal GDC selection program for the embolization of intracranial aneurysm. METHODS: Twenty highly cost-effective cases of intracranial aneurysm embolized with GDC dense packing were collected. Each of them contains information including aneurysm's volume measured by three-dimension digital subtraction angiography (3D DSA), aneurysm's location, maximum transverse diameter, maximum length diameter, and GDC selection program. An expert system made up of a case base, a mathematical model simulating experts' experience (established with the help of data mining techniques combining multi-layer perceptron network with polyhedrons in high dimensional space), and data envelopment analysis (DEA), was implemented. RESULTS: When the user inputted four required parameters (volume, location, maximum transverse diameter, and maximum length diameter) into the expert system and clicked the "program design" button, candidate GDC selection program(s) would be presented in the result box. CONCLUSION: Case base, data mining techniques, and DEA can be used to establish the expert system that automatically generates optimal GDC selection program for the embolization of intracranial aneurysm. Its clinical value needs to be further evaluated.

Adult↗
PubMed2002

[Spinal dural arteriovenous fistulae associated with perimedullary arteriovenous fistulae: imaging characteristics and surgical treatment].

OBJECTIVE: To enhance the clinical doctors' cognizance of atypical spinal dural arteriovenous fistulae (SDAVFs) associated with perimedullary anteriovenous fistulae (PMAVFs). METHODS: The clinical imaging and surgical therapy of 3 patients with PMAVFs were analyzed retrospectively. RESULTS: The clinical presentations of the 3 patients were not significantly different from those of typical SDAVFs. They were verified by repeated spinal angiography that the anterior spinal artery (ASA) is supplied to the drainage-vein. The 3 patients were treated surgically. First two operations were performed to eliminate the supply of ASA and dural branch, then the supply of the dural branch was amputated, and finally both the ASA and dural branch supplies were excised successfully. Clinical symptoms of the 3 patients were improved after treatment. CONCLUSIONS: It is necessary to perform thorough spinal angiography in patients with SDAVFs to exclude another fistula. The key point in the treatment of such patients is successfully to terminate both the spinal feeder and dural branch feeder.

Adult↗
PubMed2002

[Diagnosis and treatment of spinal cord cavernous angioma].

OBJECTIVE: To investigate the diagnosis and treatment of patients with spinal cord cavernous angioma. METHODS: Clinical data on 23 patients with intramedually cavernous angiomas were analyzed. The function of the spinal cord was evaluated before and after treatment using the Aminoff & Logue scale. RESULTS: All patients underwent resection of spinal cord cavernous angioma except two patients who refused surgical treatment. Complete removal was achieved in 18 patients, and subtotal removal in 3. Twenty-one patients with spinal cavernous angioma were confirmed pathologically. The postoperative neurological status was improved in 15 patients, remained unchanged in 4, and aggravated in 2. No deaths occurred. CONCLUSIONS: MRI is specific in diagnosis of intramedually cavernous angioma. The outcome of surgical treatment is better. Surgical treatment is suitable for patients with symptoms.

Adolescent↗
PubMed2002

[Three dimensional digital subtraction angiography in volume embolization ratio measurement of densely packing experimental aneurysms].

OBJECTIVE: To calculate the volume embolization ratio of densely packing experimental aneurysms by three dimensional digital subtraction angiography (3D-DSA). METHODS: Six experimental crotch aneurysms were created microsurgically in the common carotid artery of white rabbits. Two weeks later, each aneurysm's volume was measured with 3D-DSA surface shaded display(SSD) and the correction of lacteprene balloon calibration method. In the same time, the aneurysms were densely packed with electric detachable coils. The volume of coils that were used in each aneurysm was calculated separately. The ratio of coils volume and aneurysm volume was the volume embolization ratio (VER). RESULTS: The aneurysms volumes measured by 3D DSA SSD ranged from 0.037 to 0.087 ml. The VER ranged from 23.5% to 32.5% (average 27.4%). CONCLUSION: The minimum VER of densely packing experimental crotch aneurysms with electronic detachable coils was 23.5%.

Angiography, Digital Subtraction↗
PubMed2002

[Experience with transluminal stent-assisted angioplasty for intracranial vascular diseases].

OBJECTIVE: To assess the value of stent-assistant angioplasty for intracranial vascular diseases. METHODS: Thirteen patients with intracranial vascular diseases were treated consecutively by stent-assistant angioplasty for different purposes. Of these patients 7 had symptomatic intracranial artery stenosis, 3 intracranial wide-neck aneurysms, 2 intracranial pseudoaneurysms, and 1 bilateral transverse sinus stenosis. Clinical procedures and technical data of the patients were retrospectively analyzed. RESULTS: In the 7 patients, the degree of intracranial artery stenosis reduced from 83% to 5%. Three months after the operation they exhibited good patency of stented lesions. Intracranial wide neck aneurysms (with 2 pseudoaneurysms) were successfully embolized with GDC in 5 patients. The patients with bilateral transverse sinus stenosis were implanted a self-expanded stent in the right transverse sinus. One patient failed because of the tortuous configuration of the left jugular bulb, but the patient's symptoms were improved quickly after the procedure. CONCLUSION: Stent-assistant angioplasty is a useful technique for selected intracranial vascular diseases, and it needs further investigation.

Adult↗
PubMed1999

Balloon occlusion test and therapeutic occlusion on traumatic carotid cavernous fistulas.

OBJECTIVE: To evaluate the safety of the balloon occlusion test(BOT) and therapeutic occlusion of the internal carotid artery(ICA). METHODS: The data of 43 patients hospitalized consecutively with traumatic intractable carotid cavernous fistulas (TICCF) were analyzed. Therapeutic occlusion of ICA was performed on 39 cases and BOT was only performed on the remaining 4 cases. Our assessment consisted of: (1) angiographic evaluation of collateral circulation with or without BOT of ICA, and (2) evaluation of clinical tolerance to therapeutic occlusion of ICA with hypotensive challenge for 30 minutes. Complications of BOT and therapeutic occlusion of ICA were also analyzed retrospectively. RESULTS: Complications related to BOT occurred in 1 case (2.3%) without causing permanent deficits. Complications related to therapeutic occlusion of ICA occurred in 4 cases (10%), including 1 technical (2.5%), 2 temporary (5%) and 1 permanent (2.5%) deficit. There was no fistula recurrence or mortality. CONCLUSIONS: BOT of ICA is safe and economical. The reliability of the results is almost the same compared with that of other more complicated methods of assessing therapeutic occlusion of ICA. And it is easy to treat TICCF with therapeutic occlusion of ICA.

Journal Article↗