Search PubMed⌕ Search

Biomedical subjects

A P Yim

Publications and source records attributed to A P Yim.

At least 19 recordsLinked to original sources
PubMed2001

Place of video-thoracoscopy in thoracic surgical practice.

The advent of video-endoscopy revolutionizes the practice of surgery. Within a short span of time, video-assisted thoracic surgery (VATS) has become an acceptable approach to a wide range of thoracic procedures. The use of VATS as a diagnostic modality is now well established. For therapeutic procedures, VATS has also been generally accepted for the treatment of such conditions as primary spontaneous pneumothorax, loculated effusions, thoracodorsal sympathectomy, and resection of simple mediastinal cysts. Its roles in more complex procedures such as thymectomy and anatemic lung resections, however, remain poorly defined at present, even though the existing intermediate-term results are encouraging. VATS is still in evolution. Miniaturization of instruments promises to reduce access-induced trauma even further. On the other hand, attention to cost-containment is essential if VATS is to be applicable to patients in developing countries. Technology will continue to change. Carefully conducted clinical trials should precede the general acceptance of any new technology, no matter how attractive it may appear initially.

Humans↗
PubMed2001

Direct measurement of nitric oxide release from saphenous vein: abolishment by surgical preparation.

BACKGROUND: Surgical preparation (distension) of the saphenous vein (SV) is applied routinely during harvesting in coronary artery bypass grafting (CABG). However, mechanical distension may impair the endothelium, which plays an important role in long-term patency. The present study investigated the effect of surgical preparation of the SV on nitric oxide (NO) release from the endothelium by direct measurement of NO. METHODS: Saphenous vein segments taken from CABG patients were cut open longitudinally and placed in an organ chamber. An NO-sensitive electrode and NO meter were used to directly measure NO release induced by acetylcholine (ACh) and bradykinin (BK) from the surgically prepared veins (PV) compared with the control (nondistended) veins. RESULTS: The basal release of NO in the PV group was significantly lower than that in the control group (3.4 +/- 1.4 nM, n = 9 versus 9.9 +/- 2.8 nM, n = 13, p = 0.002). The maximum concentrations of NO release induced by ACh and BK in the PV group were also significantly lower than those in the control veins (for ACh 10(-6) mol/L: 9.6 +/- 3.1 nM, n = 8 versus 41.9 +/- 11.2 nM, n = 12, p = 0.005; for BK 10(-8) mol/L: 8.3 +/- 3.7 nM, n = 7 versus 37.9 +/- 6.1 nM, n = 9, p = 0.003). Further, the duration of NO release in the PV group was significantly shorter than that in control veins (1.5 +/- 1.3 minutes, n = 8 versus 8.1 +/- 1.9 minutes, n = 8, p < 0.001). CONCLUSIONS: Surgical preparation almost abolishes NO release by the SV and this may significantly contribute to the low long-term patency rate of the vein graft.

Endothelium, Vascular↗
PubMed2001

Effects of potassium channel opener aprikalim on the receptor-mediated vasoconstriction in the human internal mammary artery.

BACKGROUND: Arterial grafts for coronary artery bypass grafting such as the internal mammary artery (IMA) may develop spasm perioperatively. The purpose of this study was to investigate the effects of the potassium channel opener, aprikalim, on the receptor-mediated vasoconstriction in the human IMA in vitro. METHODS: We studied 160 IMA rings taken from coronary artery surgery in organ baths. The interaction between aprikalim and four vasoconstrictors 5-hydroxytryptamine (5-HT), norepinephrine (NE), endothelin-1 (ET-1), and angiotensin II (AII) was investigated in two ways. RESULTS: Aprikalim relaxed IMA rings precontracted by the vasoconstrictors to 66.40 +/- 5.9% for 5-HT (EC50: -6.78 +/- 0.26 LogM), 57.40 +/- 5.5% for NE (-6.54 +/- 0.39 LogM), 81.00 +/- 6.7% for ET-1 (-6.58 +/- 0.26 LogM), and 93.90 +/- 2.5% for AII (-7.80 +/- 0.23 LogM). The relaxation in endothelium-denuded rings contracted by AII was similar to that in the endothelium-intact rings. The relaxation was attenuated by glibenclamide (3 microM) in 5-HT or NE-precontracted IMA. Pretreatment with aprikalim at 1 microM depressed AII-induced contraction (33.20 +/- 7.5% versus 59.70 +/- 7.3%, p < 0.01) but only shifted the curves rightward for 5-HT or NE (EC50 3.1 or 4.3-folds higher, p < 0.05), whereas at 30 microM it also significantly depressed the maximal contraction for 5-HT (35.70 +/- 4.9% versus 103.30 +/- 9.8%, p < 0.001) and NE (90.60 +/- 15.6% versus 125.60 +/- 7.9%, p < 0.05). In contrast, aprikalim did not significantly depress the contraction induced by ET-1 (p > 0.05). CONCLUSIONS: We conclude that aprikalim has vasorelaxant effects on IMA and the effect is vasoconstrictor-selective and endothelium-independent. Aprikalim may provide clinically useful vasorelaxant effects in coronary bypass surgery.

Angiotensin II↗
PubMed2001

ATP-sensitive potassium channel openers may mimic the effects of hypoxic preconditioning on the coronary artery.

BACKGROUND: This study was designed to investigate the effects of the potassium channel opener KRN4884 in mimicking hypoxic preconditioning on coronary arteries and to explore the possible mechanisms. METHODS: In the organ chamber, porcine coronary artery rings (n = 96) were studied in 6 groups (n = 16 in each group): I. CONTROL: normoxia (pO2 > 200 mmHg); II. Hypoxia-reoxygenation: 60-minute hypoxia (pO2 < 15 mmHg) followed by 30-minute reoxygenation; III. Preconditioning: 5-minute hypoxia followed by 10-minute reoxygenation prior to hypoxia-reoxygenation; IV. KRN4884-pretreatment: KRN4884 (30 microM) was added into the chamber 20 minutes before hypoxia-reoxygenation; V. 5-HD-pretreatment: sodium 5-hydroxydecanoate (5-HD, 10 microM) was given 20 minutes prior to KRN4884-pretreatment; and VI. GBC-pretreatment: glibenclamide (GBC, 3 microM) was added 20 minutes prior to KRN4884-pretreatment. Concentration-contraction curves for U46619 (n = 8 in each group) were constructed. Concentration-relaxation curves for bradykinin (n = 8 in each group) related to endothelium-derived hyperpolarizing factor (EDHF) were established in the rings precontracted with U46619 (30 microM) in the presence of Nomega-nitro-L-arginine (L-NNA, 300 microM) and indomethacin (7 microM). RESULTS: The maximal relaxation induced by bradykinin was reduced in hypoxia-reoxygenation (54.6 +/- 4.3% versus 85.2 +/- 5.7% in control, p = 0.001). This reduced relaxation was recovered in KRN4884-pretreatment (78.9 +/- 3.7%, p = 0.014) or preconditioning (79.9 +/- 3.7%, p = 0.009). 5-HD- but not GBC-pretreatment abolished the effect of KRN4884-pretreatment (78.9 +/- 3.7% versus 53.5 +/- 4.7%, p = 0.009). CONCLUSIONS: Hypoxia-reoxygenation reduces the relaxation mediated by EDHF in the coronary artery. This function can be restored by either hypoxic preconditioning or the potassium channel opener KRN4884. The mechanism of such effect is mainly related to the mitochondrial ATP-sensitive K+ channels.

Adenosine Triphosphate↗
PubMed2001

Macro-porosity is necessary for the reduction of neointimal and medial thickening by external stenting of porcine saphenous vein bypass grafts.

BACKGROUND: placing external non-restrictive macro-porous stents around porcine vein grafts prevents neointima formation and medial thickening in both the short and long term. Whether the porosity of the stent material influences this effect, however, has not been determined. Therefore, the effect on neointimal and medial thickening of external macro-porous (polyester) and micro-porous (polytetrafluorethylene) stents of equal diameter were compared. The effect on expression of platelet-derived growth factor (PDGF), a potent mediator of vascular smooth muscle cell migration and proliferation and its receptors was also investigated. METHODS AND RESULTS: saphenous vein-carotid artery interposition grafting was performed in Landrace pigs with external placement of 8 mm diameter macro- and micro-porous stents contralaterally. One month after surgery, graft wall dimensions, PDGF and PDGF receptor expression and cell proliferation using proliferating cell nuclear antigen (PCNA) were measured on histological sections. Macro-porous stents significantly reduced neointimal and medial thickening compared with micro-porous stents (0.1+/-0.02 vs. 0.25+/-0.03 mm, P<0.002, and 0.10+/-0.02 vs. 0.17+/-0.02 mm, P<0.014, respectively). Macro-porous stents significantly reduced the percentage of cells expressing PDGF and PCNA, compared with micro-porous stents (36+/-9 vs. 80+/-7, P < 0.002, and 11+/-3 vs. 21+/-2, P < 0.02, respectively). The percentage of cells expressing PDGF receptors was similar with both the stent types. Adventitial microvessel formation occurred across macro-porous stents but was markedly suppressed by micro-porous stents. CONCLUSIONS: porosity is crucial to the efficacy of external stents in reducing neointima formation in porcine vein grafts. Decreases in PDGF expression and cell proliferation accompany the reduction in neointima formation. In addition, macro-porous stents allow adventitial microvessels to connect with the vasculature outside the stent, thereby potentially improving oxygenation. Although external stenting is highly effective in reducing neointima formation after vein grafting, the properties of the stent material necessary for this effect have not been defined. This study establishes that macro-porosity is one essential feature required to reduce PDGF expression cell proliferation and neointima formation.

Animals↗
PubMed2001

Vascular endothelial growth factor-mediated endothelium-dependent relaxation is blunted in spontaneously hypertensive rats.

The vasodilatory effect of VEGF has not been characterized in the setting of hypertension. This study investigated the in vitro vasorelaxant effects of VEGF in organ chambers in the aorta of the adult (12-week-old) spontaneously hypertensive rats (SHR), young (4-week-old) SHR without hypertension, and age-matched Wistar-Kyoto (WKY) rats compared with acetylcholine (ACh). Cumulative concentration-relaxation curves were established for VEGF (approximately 10(-12)-10(-8.5) M) and ACh (approximately 10(-10)-10(-5) M) in U46619 (10(-8) M)-induced contraction. VEGF induced endothelium-dependent relaxation that was significantly reduced in the adult SHR compared with the age-matched WKY control (87.8 +/- 2.8 versus 61.4 +/- 8.6%, P = 0.01). These responses were significantly attenuated by pretreatment with N(omega)-nitro-L-arginine (L-NNA, 300 microM) alone (SHR: 25.1 +/- 1.9%; WKY: 21.0 +/- 2.6%; P = 0.01) or indomethacin (7 microM) + L-NNA (SHR: 30.2 +/- 2.1%; WKY: 35.0 +/- 2.9%; P = 0.01). Further addition of oxyhemoglobin (20 microM) abolished the residual relaxation and reduced the relaxation induced by nitroglycerin. ACh induced similar responses to VEGF. In contrast, pretreatment with indomethacin alone enhanced VEGF- or ACh-induced relaxations and the effect was greater in the adult SHR than in WKY rats. In contrast to the adult SHR versus WKY rats, there were no significant differences of VEGF- or ACh-induced relaxations between young SHR and WKY rats. The results demonstrate that VEGF induces endothelium- or nitric oxide-dependent relaxation, which is blunted in the adult SHR. The mechanism of this impairment may be related to decreased release of NO although increased release of contracting factors from the dysfunctional endothelium may also be involved.

Acetylcholine↗
PubMed2000

Follicular dendritic cell sarcoma of the neck: report of two cases complicated by pulmonary metastases.

BACKGROUND: Follicular dendritic cell (FDC) sarcoma is an uncommon neoplasm occurring primarily in lymph nodes but also in extranodal sites. A correct diagnosis can be difficult to make, especially in the latter sites. METHODS: Two patients with FDC sarcoma of the cervical soft tissues that metastasized to the lungs are reported. Both were initially misdiagnosed as having CASTLE (carcinoma showing a thymus-like element). Additional immunohistochemical stains were performed. RESULTS: The primary tumors showed jigsaw puzzle-like lobulation resembling thymic epithelial tumor and consisted of spindly cells arranged in fascicles, whorls, and a storiform pattern. The spindly cells had indistinct cell borders, vesicular nuclei, and distinct nucleoli. Perivascular spaces were present. Lymphocytes were sprinkled throughout the tumor in one case but were sparse in the other. The metastatic deposits in the lungs appeared 27 and 2 years, respectively, after the initial presentation and were histologically similar to the original tumors. The FDC nature of the primary and metastatic tumors was confirmed by positive staining with CD21/CD35 cocktail and CD23 and by negative staining for cytokeratin. In one case, in direct continuity with the main tumor, there was a lobulated lesion composed of small lymphocytes punctuated by large cells with vesicular nuclei, histologically reminiscent of thymoma. The large cells were shown by immunohistochemistry to represent FDCs forming complex interconnecting meshworks. It is unclear whether this contiguous mass represents a precursor lesion or an unusual-looking component of the neoplasm. CONCLUSIONS: FDC sarcoma can look deceptively like a thymic epithelial tumor histologically. A correct diagnosis requires a high index of suspicion and immunohistochemical evaluation. The tumor shows a propensity to metastasize to the lungs, which can be delayed until more than 20 years after initial presentation.

Adult↗
PubMed2000

Lack of expression for the suppressor PML in human small cell lung carcinoma.

The promyelocytic leukemia (PML) gene, which encodes a transformation and growth suppressor, was first identified at the chromosomal translocation break point t(15;17) in acute promyelocytic leukemia (PML). To determine if the PML gene might be involved in other neoplasias such as lung cancer, PML expression was analyzed by immunohistochemical staining and in situ hybridization. Considerable PML protein expression in the PML-oncogenic domain (POD) structure was found in adenocarcinomas (ADC) and squamous cell carcinomas (SCC) of the lung, but was almost completely absent in all the small cell lung carcinomas (SCLC) examined. In situ hybridization showed that both mRNA and DNA of PML were present in SCLC and in normal lung, suggesting that the decreased protein expression was due to either a defect in translation or protein instability, rather than the consequence of decreased transcription or gene deletion. Double staining showed that PML expression was inversely correlated with the proliferation marker Ki-67 and positively correlated with levels of apoptotic cells in these tumors. To determine if the precursor cells of SCLC, the neuroendocrine-producing cells, express PML, double labeling was performed with PML and chromogranin A, a bio-marker for neuroendocrine cells. Neuroendocrine cells from normal tissues were found to be PML positive, indicating that the lack of PML protein in SCLC is associated with the tumorigenic phenotype and is not the result of cell-lineage specificity. Thus, the decreased PML expression may play an important role in SCLC development.

Adenocarcinoma↗
PubMed2000

VATS lobectomy reduces cytokine responses compared with conventional surgery.

BACKGROUND: Video-assisted thoracic surgery (VATS) lobectomy for early lung cancer has been shown to be technically feasible. Comparative studies on laparoscopic versus open procedures indicate that laparoscopy may reduce inflammatory reactions as reflected by the lesser release of cytokines. We investigated the cytokine responses following VATS and conventional lobectomy for clinical stage I lung cancer. METHODS: Thirty-six patients with clinical stage I nonsmall cell lung cancer were studied. 18 patients underwent VATS lobectomy and the other 18 by conventional thoracotomy. There were no differences between the two groups with respect to age, gender, pulmonary function, smoking history, comorbidity, tumor size, and pathology. Plasma levels of tumor necrosis factor-alpha (TNF-alpha), interleukin (IL)-1beta, IL-6, IL-8, and an antiinflammatory cytokine IL-10 were measured before surgery, at the end of the procedure, and 4, 8, 24, and 48 hours thereafter in all patients. RESULTS: There was no mortality or major complication in either group. Analgesic requirement was significantly less in the VATS group. Although the release of TNF-alpha and IL-1beta were minimal after surgery in both groups, the levels of IL-6, IL-8, and IL-10 were elevated. IL-6 and IL-8 levels were significantly lower in the VATS group at the end of surgery than in the open group. In addition, reduced release of IL-10 was also observed in the VATS group shortly after surgery. CONCLUSIONS: VATS lobectomy is associated with reduced postoperative release of both proinflammatory and antiinflammatory cytokines compared with the open approach. The clinical significance of these findings remains to be fully elucidated.

Aged↗
PubMed2000

Inhibition of vasoconstriction by angiotensin receptor antagonist GR117289C in arterial grafts.

BACKGROUND: Angiotensin II (AII) has been suggested to be one of the important factors for genesis of graft spasm in coronary artery bypass surgery. The aim of this work was to investigate the effects of the nonpeptide angiotensin receptor AT1 antagonist GR117289C on the contraction induced by AII and other vasoconstrictors in isolated human internal mammary artery (IMA) preparations. METHODS: Two hundred eight IMA rings taken from 64 patients undergoing coronary artery bypass grafting were studied in organ baths. The interaction between GR117289C and AII or the other vasoconstrictors (U46619, norepinephrine, endothelin-1, and potassium chloride) was investigated in two ways. RESULTS: GR117289C induced near-maximal relaxation (94.5% +/- 2.9%) in IMA rings precontracted by AII. In IMA rings incubated with 1 or 10 nmol/L GR117289C, contractile responses to AII were attenuated in a concentration-related manner, whereas the dose-response curve did not shift to the right when higher doses of AII were administered, suggesting that the AT1 receptor blockade was noncompetitive in nature. Moreover, GR117289C also induced significant relaxation (82.9% +/- 8.1%) in IMA rings precontracted by U46619, but no inhibitory responses to U46619 could be observed when IMA rings were incubated with GR117289C. GR117289C did not alter responses to potassium chloride, norepinephrine, and endothelin-1. CONCLUSIONS: These results indicate that GR117289C is a potent, selective, noncompetitive AT1 receptor antagonist that may have a possible antagonistic effect on the thromboxane A2 receptor. Because AII and thromboxane A2 are important vasoconstrictors in the genesis of graft spasm, GR117289C may become an alternative treatment to relieve graft spasm.

Aged↗
PubMed2000

'Needlescopic' video-assisted thoracic surgery for palmar hyperhidrosis.

OBJECTIVE: The video-assisted thoracic surgery (VATS) approach for thoracodorsal sympathectomy has been well accepted. We report the use of ultra-fine thoracoscopic equipment for this procedure, based on the experience from two centers in Asia. MATERIALS AND METHODS: Thirty-eight patients with palmar hyperhidrosis underwent bilateral VATS thoracodorsal sympathectomy using 2-mm instruments exclusively. General anesthesia with selective one lung ventilation was used. Carbon dioxide insufflation was used when lung collapse was found to be inadequate. In 11 patients, the sympathetic chain was excised (T2-T3 for palmar hyperhidrosis alone, extending to T4 for axillary hyperhidrosis), and in 27 patients, the chain was cauterized. The choice of procedure reflects the surgeon's preference. No chest drains were left after the procedure and no stitching of the wound was necessary. RESULTS: There was no mortality or major complications. A small pneumothorax was found in the postoperative chest X-ray in three patients. They all resolved without further intervention. Twenty-seven patients were discharged on the same day of admission, and 11 patients were discharged on postoperative day one. After an average follow-up of 16 months (range 5-28), there has been no recurrence of symptoms. Compensatory truncal hyperhidrosis was encountered in two patients, but the symptoms were not severe enough to interfere with lifestyle, and this required no further treatment. CONCLUSION: Thoracodorsal sympathectomy using 2-mm instruments is technically feasible and is associated with an excellent clinical outcome. Limitations of the equipment, however, exist (narrow field of vision, lower resolution and difficulty in maintaining fine control), and we are currently restricting its use to relatively simple procedures.

Adult↗
PubMed2000

Long-term outcome after resection for bronchial carcinoid tumors.

OBJECTIVES: We sought to determine the long-term survival of patients treated for bronchial carcinoid tumors and whether lesser resections have had an effect on outcomes. METHODS: We conducted a retrospective, multi-institutional review of patients treated surgically for primary bronchial carcinoid tumors since 1980. Operative approach, pathologic stage, histology, surgical complications, tumor recurrence, and long-term survival were assessed. RESULTS: There were 50 men and 89 women with a mean age of 52.2+/-17.4 and 58.9+/-13.3 years, respectively (P=0.021). Men were more likely to be current or former smokers than were women. Operations included lobectomy or bilobectomy in 110, pneumonectomy in four, wedge resection in 22, and bronchial sleeve resection only in three patients; resection was performed thoracoscopically in six patients. One patient died postoperatively. Stages were I, 121; II, nine; III, six; and IV, three. Typical carcinoid tumors were stage I in 100 and more advanced (stages II-IV) in nine, whereas atypical carcinoid tumors were stage I in 18 and more advanced in eight (P=0. 002). Median follow-up was 43 months (range 1-149) during which 21 (15%) patients died (four from recurrent cancer) and 19 patients (14%) were lost to follow-up. Recurrent cancer developed in 2/98 patients with typical and 5/25 patients with atypical subtypes (P<0. 001; log-rank test). The likelihood of recurrence was related to histological subtype (relative risk 7.9 for atypical carcinoid; 95% confidence interval 1.4-43.5). Five-year survival was 88% for stage I patients and was 70% for patients with more advanced stages. When stratified by stage, survival was related to age (relative risk=1.9 for a 10 year increase in age; 95% confidence interval 1.2-2.9) and possibly to the histological subtype, but not to patient gender, year of operation, or type of operation performed. CONCLUSIONS: Either major lung resection or wedge resection is appropriate treatment for patients with early stage typical bronchial carcinoid tumors. Survival is favorable for early stage tumors regardless of histological subtype. Local recurrence is more common among patients with atypical subtypes, suggesting that a formal resection may improve long-term outcome.

Adolescent↗
PubMed2000

Therapeutic video-assisted thoracoscopic surgical resection of colorectal pulmonary metastases.

OBJECTIVE: Careful patient selection is vital when video-assisted thoracoscopic surgical (VATS) therapeutic pulmonary metastasectomy of colorectal carcinoma is considered. Complete resection of all metastatic disease remains a vital concept. We reviewed our VATS experience for therapeutic metastasectomy of peripheral colorectal pulmonary metastases. METHODS: Over 90 months, therapeutic VATS metastasectomy was accomplished upon 80 patients with colorectal metastases. Thin cut computed tomography (CT) was central in identifying lesions. The mean interval from primary carcinoma to VATS resection was 41 months (1-156 months; median, 33). A solitary lesion was resected in 60 patients and multiple (2-7) lesions resected in 20 patients. Statistics were obtained using the Student's t-test. RESULTS: No operative mortality or major postoperative complications occurred. The hospital stay was 4.5+/-2. 2 days (range, 1-13). All lesions were resected by VATS, with four conversions to thoracotomy to improve the margins. The mean survival of patients with one lesion was 34.8 months compared with 26.5 months for patients with multiple lesions (P=0.37). The mean survival was 20.5 months when metastases occurred <3 years vs. 28.1 months for >3 years from primary carcinoma resection (P=0.20). Twenty-five (31%) patients are disease free; with a mean interval of 38.7 (3-84; median, 35) months. Sixty-nine percent (55/80) of patients developed a recurrence: 6/80 (8%) local; 19/80 (24%) regional (same hemithorax away from resection); and 30/80 (38%) distant. The overall survival at 1 year was 81.2%, 48.4% at 3 years and 30.8% at 5 years. CONCLUSIONS: Therapeutic VATS resection of colorectal metastases appears efficacious. Preoperative CT can identify peripheral colorectal metastases amenable to VATS. Conversion to thoracotomy is indicated when none of the lesions identified by CT are found or when clear surgical margins are jeopardized.

Adult↗
PubMed2000

Effects of potassium channel opener KRN4884 on human conduit arteries used as coronary bypass grafts.

AIMS: The effects of a new potassium channel opener KRN4884 on human arteries have not been studied. This study was designed to investigate the effects of KRN4884 on the human internal mammary artery (IMA) in order to provide information on possible clinical applications of KRN4884 for preventing and relieving vasospasm of arterial grafts in coronary artery bypass grafting. METHODS: IMA segments (n = 140) taken from patients undergoing coronary surgery were studied in the organ chamber. Concentration-relaxation curves for KRN4884 were established in the IMA precontracted with noradrenaline (NA), 5-hydroxytryptamine (5-HT), angiotensin II (ANG II), and endothelin-1 (ET-1). The effect of glibenclamide (GBC) on the KRN4884-induced relaxation was also examined in NA or 5-HT-precontracted IMA. Concentration-contraction curves for the four vasoconstrictors were constructed without/with pretreatment of KNR4884 (1 or 30 microM) for 15 min. RESULTS: KRN4884 induced less relaxation (P < 0.05) in the precontraction induced by ET-1 (72.9 +/- 5.5%) than by ANG II (94.2 +/- 3.2%) or NA (93.7 +/- 4.1%) with lower EC50 (P < 0.05) for ANG II (-8.54 +/- 0.54 log M) than that for NA (-6.14 +/- 0.15 log M) or ET-1 (-6.69 +/- 0.34 log M). The relaxation in the IMA pretreated with GBC was less than that in control (P < 0.05). KRN4884-pretreatment significantly reduced the contraction (P < 0.05) induced by NA (151.3 +/- 18.4% vs 82.7 +/- 8. 7%), 5-HT (82.7 +/- 12.2% vs 30.1 +/- 7.3%), and ANG II (24.3 +/- 6. 3% vs 5.4 +/- 1.6%), but did not significantly reduce the contraction induced by ET-1 (P > 0.05). CONCLUSION: KRN4884 has marked vasorelaxant effects on the human IMA contracted by a variety of vasoconstrictors and the effect is vasoconstrictor-selective.

Aged↗
PubMed2000

Thoracoscopic removal of intrathoracic neurogenic tumors: a combined Chinese experience.

OBJECTIVE: To review the surgical and clinical results of minimally invasive resection of intrathoracic neurogenic tumors using a video-assisted thoracoscopic technique. SUMMARY BACKGROUND DATA: Thoracoscopy has emerged as a possible means for diagnosing and managing various intrathoracic disorders. Benign intrathoracic tumors often are ideal lesions for resection using a video-assisted technique. The authors report on their combined experience with the thoracoscopic resection of 143 intrathoracic neurogenic tumors. METHODS: Between March 1992 and February 1999, 143 patients with intrathoracic neurogenic tumors were diagnosed and underwent resection using video-assisted thoracoscopic techniques in three teaching centers. Case selection, surgical technique, and clinical results were reviewed. RESULTS: The average age of the patients was 40.8 years; 57.3% were male. Thirty-eight patients (27%) had symptoms attributable to the masses. Seventy-two masses were neurofibromas, 33 were neurilemmomas, 7 were paragangliomas, and 31 were ganglioneuromas. All but seven tumors were located in the posterior mediastinum. The masses were on average 3.5 cm in greatest diameter. The mean surgical time was 40 minutes, and the average hospital stay was 4.1 days. There were no major postoperative complications or recurrences to date. Nine patients reported paresthesias over the chest wall during a mean follow-up of 29 months. CONCLUSIONS: Resection of intrathoracic neurogenic tumors using a thoracoscopic technique based on standard surgical indications would seem to be appropriate. Most of these masses are benign and readily removed. For dumbbell tumors, a combined thoracic and neurosurgical approach is mandatory.

Adult↗