Synergistic Cu/Pd-Catalyzed Asymmetric Allenylic Alkylation of Azomethine Ylides for the Construction of α-Allene-Substituted Nonproteinogenic α-Amino Acids.

An unprecedented asymmetric allenylic alkylation of readily available imine esters, which was enabled by a synergistic Cu/Pd catalysis, has been developed. This dual catalytic system possesses good substrate compatibility, delivering a diverse array of nonproteinogenic α-allenylic α-mono- or α,α-disubstituted α-amino acids (α-AAs) with high yields and generally excellent enantioselectivities. Furthermore, the scalability and practicability of the current synthetic protocol were proven by performing gram-scale reactions and by the first catalytic asymmetric synthesis of naturally occurring (S)-γ-allenic α-amino acid, respectively.

Ag(I)-Catalyzed Kinetic Resolution of Cyclopentene-1,3-diones.

An efficient kinetic resolution of readily available racemic cyclopentene-1,3-diones has been developed via a Ag(I)-catalyzed asymmetric 1,3-dipolar cycloaddition of azomethine ylides. This methodology shows good functional-group tolerance, delivering an array of synthetically valuable cyclopentene-1,3-diones with excellent stereoselectivity and generally high resolution efficiency ( s = 48-226) accompanied by the biologically important fused pyrrolidine derivatives. Notably, this strategy allows facile access to the key intermediates for the synthesis of (+)-madindolines A and B.

Silver(I)-Catalyzed Atroposelective Desymmetrization of N-Arylmaleimide via 1,3-Dipolar Cycloaddition of Azomethine Ylides: Access to Octahydropyrrolo[3,4-c]pyrrole Derivatives.

A highly efficient Ag(I)-catalyzed atroposelective desymmetrization of N-(2-t-butylphenyl)maleimide via 1,3-dipolar cycloaddition of in situ generated azomethine ylides has been established successfully, affording a facile access to a series of biologically important and enantioenriched octahydropyrrolo[3,4-c]pyrrole derivatives in generally high yields (up to 99%) with excellent levels of diastereo-/enantioselectivities (up to 99% ee, >20:1 dr). Subsequent transformations led to fascinating 2H-pyrrole and polysubstituted pyrrole compounds without loss of stereoselectivity. The absolute configuration of the generated chiral axis has been unambiguously identified as (M) through single-crystal X-ray diffraction analysis. Furthermore, on the basis of the comprehensive experimental results and the absolute configuration of one of the cycloadducts, the origin of the stereoselectivity was proposed to be attributed to the steric congestion imposed by the bulky PPh2 group of the chiral ligand and the tert-butyl group of N-(2-t-butylphenyl)maleimide. The possible hydrogen bond interaction between the NH2 group of the chiral ligand and one of the carbonyl groups of N-(2-t-butylphenyl)maleimide is considered to facilitate stabilizing the transition state.

Silver(I)-Catalyzed Enantioselective Desymmetrization of Cyclopentenediones: Access to Highly Functionalized Bicyclic Pyrrolidines.

A highly enantioselective desymmetrization of prochiral cyclopentenediones via Ag(I)-catalyzed asymmetric 1,3-dipolar cycloaddition of azomethine ylide has been developed successfully. The methodology performs well over a broad scope of substrates, which provides facile access to a series of highly functionalized bicyclic pyrrolidine/cyclopentane derivatives in good to high yields with excellent stereoselectivities.

[Juvenile nasopharyngeal angiofibroma: endoscopic surgery and follow-up results].

OBJECTIVE: To present the changes of surgical approaches for the resection of juvenile nasopharyngeal angiofibromas (JNA) and the follow-up results. METHODS: The clinical records of 59 patients with JNA treated under endoscope between 2002 and 2009 were reviewed retrospectively. The patients were divided into two groups: Group A (Radkowski I a-II b) and Group B (Radkowsik II c-III b). The tumor stages, feeding vessels, operating time, complications and recurrence were observed and recorded. RESULTS: There were 7 patients with stage I a, 3 patients with stage I b, 5 patients with stage II a, 6 patients with stage II b, 4 patients with stage II c, 23 patients with stage III a, 11 patients with stage III b. The average age at diagnosis in Group A (21 cases) was 23.9 years old. The average operating time was (106.0 +/- 43.7) min. The follow-up ranged from 3 months to 74 months (median 36 months) except for 3 missing cases. The average age at diagnosis in Group B (38 cases) was 16.2 years old and the average operating time was (152.9 +/- 58.0) min. The follow-up ranged from 3 months to 87 months (median 25 months) except for 5 missing cases. During follow-up, 6 patients in group B recurred. Infarction of thalamencephalon happened in 1 patient in group B who recovered totally afterwards. The difference in operating time between two groups was statistically significant (t = -3.232, P = 0.002). The life table was used to evaluate the survival curves and Log-rank test showed that the difference of recurrent time between two groups was statistically significant (P = 0.03). CONCLUSIONS: The key techniques to remove tumor are bleeding control, drilling-out the bone that tumor invaded. Transpterygoid or posterolateral wall of maxillary sinus approach are recommended for tumors that extend to infratemporal fossa. Small and intermediate-sized JNA which have no deep invasion of skull base (RadkowskiIa-II b) have a low morbidity. JNA at Radkowski stage IIc and above have residual and recurrent risk.

[Endoscopic nasal lateral wall dissection approach to maxillary sinus].

OBJECTIVE: To report a new approach to maxillary sinus without ablation of nasolacrimal duct and inferior turbinate by endoscopic nasal lateral wall dissection (ENLWD). The preliminary clinical application results, the operative technique and indications were discussed. METHODS: Twelve hospitalized patients, aged from 42 years to 68 years, were enrolled in this paper, 9 patients were male and 3 were female. Among the 12 patients, 8 were inverted papilloma (IP), 2 were nasal polyps, 1 was Kubo's postoperative cyst of maxillary sinus (MS) and 1 was recurrent bone cyst of maxilla. Two IP patients were excluded from this group for the follow-up time was less than 12 months. Preoperative nasal endoscopy and CT scan were done in all patients, 6 patients with tumor also received MRI examination. The operation began with a mucosal incision in front of inferior turbinate (IT) and then the lacrimal duct (LD) was dissected, thus a IT-LD flap was formed. The MS lesion was removed under endoscope when the flap was replaced medially. The inferior antrostomy was performed when the flap was repositioned. RESULTS: All 10 patients were unilateral lesion. Six MS IP patients were T3 Krouse stage. The tumor was found originating from the every part of the MS wall in the operation, especially from the anterior and medial wall. The same situation was seen in 2 patients with nasal polyps. The follow-up ranged from 7 months to 60 months (average 22 months). The shape of IT was good, and well-epithelized operative cavities were observed. Only 1 patients of IP had a local recurrence in its inferior antrostomy 6 months after operation and no recurrence was seen after local debridement. All of them had no epiphora and other complications. CONCLUSIONS: ENLWD is a new and minimally invasive approach not only to MS, in which the lesion can be thoroughly removed, but also to orbital floor and pterygopalatine fossa without ablation of lacrimal duct and IT.

[Characteristics of computed tomography of allergic fungal sinusitis].

OBJECTIVE: To sum up the characteristics of computed tomography of allergic fungal sinusitis (AFS) and to compare the CT changes with the findings in the operation. The diagnostic role of CT scan was discussed. METHODS: The CT scans of 21 patients diagnosed as AFS were analyzed. The patients ranged from 15 to 50 years old,there were 17 males and 4 females. The CT was scanned with both bony and soft tissue windows. The preoperative examinations included nasal endoscopy, skin prick test, total serum IgE and nasal secretion smear. The findings in the operation were compared with the preoperative CT scans. Histopathology and fungal smear were done postoperatively. RESULTS: Endoscopy showed that all patients had polyps with wasfy yellow or inspissated white secretion. Nine cases (11 sides) showed yellow-to-brown material similar to peanut butter in the nasal cavities. Nasal CT scan demonstrated unilateral lesion in 10 cases (10 sides) and bilateral lesions in 11 cases (22 sides), who were all pansinus diseases. CT scan demonstrated a sheet areas of high-attenuation like "ground glass" within sinuses coupled with soft tissue image around them. Bone erosion of anterior skull base was encountered in 3 cases (4 sides). One case showed the intracranial extension. Twenty cases had conceived nasal endoscopic sinus surgeries. One case underwent endoscopic sinus surgery combined with coronal approach. The yellow-to-brown material (allergic mucin) was detected in the cavities of 17 cases. Four cases had green-to-brown secretion like mud. After follow-up of 6 months to 7 years, 14 cases were cured, 7 cases improved. Among them, 3 cases had to get revision surgeries because of recurrence 2 years after surgery. CONCLUSIONS: The characteristic of a sheet area of high-attenuation like " ground glass" within sinuses coupled with soft tissue image around them in computed tomography of nasal sinus, accompanied with invasive expansion or bone erosion, has a diagnostic significance for AFS.

[Quality of life for adolescents and children with chronic sinusitis and its influencing factors].

OBJECTIVE: To investigate the status of the quality of life for adolescents and children with chronic sinusitis and its influencing factors. METHODS: Eighty-six patients were measured with the General Information Questionnaire and Chronic Sinusitis Quality of Life Scale. Six months after operation, the Chronic Sinusitis Quality of Life Scale was retested. T-test and stepwise regression were used to study the improvement and influencing factors of quality of life. RESULTS: The preoperative and postoperative quality of life scores showed a significant difference ( all P < 0. 01 ). The main factors influencing the quality of life included symptom scores (P = 0. 003) , family economic status(P = 0. 003) , parents' attitude(P = 0. 009) , extents of pathological changes(P = 0. 019) , regional disparity ( P = 0. 010) and parents' educational level (P = 0. 048). CONCLUSION: The children's subjective symptoms should be viewed as an important aspect for surgery selection. The quality of life in adolescent and children was influenced significantly by family economic status, their parents' attitude and the difference of education.

[Endoscopic surgery for nasal septal perforation].

OBJECTIVE: To describe the relevant factors of endoscopic surgery in patients with nasal septal perforation. METHODS: Twenty-three patients with nasal septal perforation were treated under nasal endoscope. Four kinds of reconstruction materials were used to accomplish the closure of perforation: residual osseous septum or temporalis fascia, inverting septal mucoperichondrial flap, autologous connective tissue insert overlaid with mucous flaps and turbinate flap. The reconstructed septum was packed by moist dressing with silicone or plastic splints. RESULTS: Seven patients underwent direct closure. Inverting flap repair for five cases, shifting flap closure for ten cases, and repair with turbinate flap in one case. During the follow-up ranging from four weeks to seven months, the successful reconstruction was achieved in 19 cases (82.6%). The problems in the remaining four cases were: mucosal flap displacement, fascia flap shrank and so caused reperforation, two perforations present with only the larger one repaired, the mucosal flap was smaller in size than the perforation. CONCLUSIONS: Intranasal endoscopic reconstruction surgery is a reasonable management for nasal septal perforation.

[Modified intranasal endoscopic Lothrop procedure].

OBJECTIVE: To report the experience of modified endoscopic Lothrop procedure (MELP) in 6 cases and to discuss the operative technique and indications. METHODS: Six patients (four males and 2 females) aged from 6 to 63 years old with frontal sinus diseases were enrolled in this study, including 3 cases of frontal mucocele, 1 case of recurrent hemangioma, 1 case of recurrent inverted papilloma and 1 case of osteoma. All patients were underwent intranasal modified Lothrop procedure with the guidance of nasal endoscope. The image-guided navigational system was used for the location of frontal sinus in 2 cases. RESULTS: The operation was successful in all 6 patients without any operative and postoperative complications. The average operation time was 3.2 h. The endoscopic examination demonstrated the wide communicational frontal sinus openings and well epithelization after 6-40 months follow-up. The patients were asymptomatic up to now and no recurrence was found. CONCLUSIONS: The modified intranasal endoscopic Lothrop procedure is an ideal surgical approach for recalcitrant frontal sinus disorders on the basis of proper selection of surgical equipments and patients by the experienced surgeon.

[Relationship between allergic factors and chronic sinusitis with or without nasal polyps].

OBJECTIVE: To explore the effects of allergic factors in chronic sinusitis and nasal polyps. METHOD: Eosinophil in nasal secretions and allergen skin test of 1882 patients with chronic sinusitis and nasal polyps were examined before endoscopic sinus surgery. The occurrence ratios of allergic symptoms and syndromes were analyzed and compared with clinical stages of chronic sinusitis and nasal polyps. RESULTS: (1) Allergic symptoms (or syndromes) were presented in 60.4% (1137 cases) of patients in different degrees, 25.3% (477 cases) patients suffered from allergic rhinitis, 2.1% (39 cases) patients had asthma; (2) The morbidities of allergic rhinitis and asthma, the positive rates of eosinophil and allergen skin test, the occurrence rates of allergic symptoms were rising with the clinical stages in type I and type II, especially in type II stage 3; (3) There were 42.2% (795 cases) positive patients in allergen skin test, among them, 94% were sensitive to perennial allergens; (4) Allergic symptoms appeared in 26.3% (495 cases) patients, among them, 99.8% attacked perennially; (5) Of all patients, there were 38.9% (732 cases) had been operated cases before, among them 38.3% (280 cases) with allergy rhinitis. In chronic sinusitis with allergy rhinitis patients, 58.7% (477 cases) were suffered from operation. CONCLUSIONS: Allergic factors,especially perennial allergic rhinitis, are relative to clinical stages of chronic sinusitis and nasal polyps. Allergic rhinitis is an important factors in recurrence.

[Acute fulminant invasive fungal sinusitis].

OBJECTIVE: To discuss the clinical presentation, diagnostic criterion and treatment principle of acute fulminant invasive fungal rhinosinusitis (AFFS). METHODS: Six patients were diagnosed as AFFS based on history, nose, especially eye symptoms with or without fever, sinus CT and MRI, endoscopic and cytological findings in the nasal cavity. Surgical debridement was performed on 5 of 6 biopsy proven AFFS patients, one of them being amputated of the orbital content. With the original disease controlled simultaneously, 4 of 5 patients were prescribed with systemic amphotericin B or liposomal amphotericin B (1 case) and one with Itraconazole orally. One patient had not been involved with any of the anti-fungi measures. RESULT: Mucor (Zygomycetes) was identified on culture in 1 patient, Rhizopus species in 2, Aspergillus in 1, Alternaria in 1 and mixed Mucor and Rhizopus in 1. All patients were proved of tissue invasion histopathologically through biopsy. One patient died without any anti-fungi therapy on the 7th admission day, 3 patients survived for 88 days, 32 and 6 months respectively and died of original diseases (diabetes 1, leukaemia 2). One patient survived 9 months and lost for follow-up, 1 patient survived 11 months after treatment. CONCLUSION: A high index of suspicion and early endoscopic investigation through nasal cavity with fungal investigation should highly be strengthened for recognition of this disease. MRI findings should be considered as, or even more, important as that of CT scan on the early diagnoses. Extensive and aggressive surgical debridement, prompt and enough dosage of antifungal therapy intravenously, together with serious controlling of the underlying disease, all take important roles in the complete control of the disease.

[Long-term outcomes and analysis of its relative factors of nasal endoscopic sinus surgery in children].

OBJECTIVE: To evaluate the results of endoscopic sinus surgery (ESS) in children with chronic sinusitis. The long-term outcomes and the relative factors were analyzed retrospectively. MATERIALS AND METHODS: A total of 268 children (432 sides), 186 males and 82 females, aged 3 to 17 years (average, 14.3) were included in this study (underwent ESS). The postoperative follow-up time of 188 cases (305 sides, 70.1%) was over one year. The management during follow-up was adopted under nasal endoscope and local anesthesia. The postoperative treatment included cleaning operative cavity, nasal irrigation, antibiotics, steroid, immune regulator, etc. RESULTS: Overall cases included 89 cases (147 sides) of chronic sinusitis, 86 cases (142 sides) of nasal polyps and 13 cases (16 sides) of mucocele respectively. The cure rate was 70.2% (132 cases). 43 cases (22.9%) were improved, while other 13 cases were of no effect. Overall symptoms, 93.1% children with headache were improved, 85.1% children were free of nasal obstruction and 60.1% children gained a relief of purulent discharge. 11 cases had no change and 2 cases were worse compared with before surgery. 34 cases with anosmia were improved or recovered after ESS. The total effective rate of ESS was 93.1%. 8 cases received a revision ESS. CONCLUSIONS: ESS in children with chronic sinusitis and polyps has a good long-term outcomes. The reasonable reservation of mucosa during ESS must be emphasized. The quality of follow-up is an important factor affecting the results of ESS. Whether the disciplinary preoperative management was made or not is the hypothesis of ESS indications.

[Surgery of ossifying fibroma of the sinuses].

OBJECTIVE: To explore the different surgical choices for treating the ossifying fibroma of the sinuses. To summarize the management and characteristics of each surgical operation. METHODS: A retrospective evaluation of thirty-five patients with ossifying fibroma of the sinuses from August 1994 to July 2001 was presented. RESULTS: Among 22 patients operated by nasal endoscopic management, complete ossifying fibroma removed was achieved in 8 cases, and the majority part of tumor removed in 14 cases. Six patients were operated through a lateral rhinotomy with radical operation in 4 cases. Five ossifying fibromas were removed with a coronal incision. Two cases underwent Caldwell-Luc' surgery. The clinical symptoms, location of ossifying fibroma, and surgical procedures were analyzed. All patients outcomes were successful, no serious complication from the surgical technique occurred. Thirty-three cases were followed-up for 1 to 8 years with an average of three and half years. Fourteen patients had no recurrence, fourteen cases lived with the remains of ossifying fibroma, and five cases recurred. CONCLUSIONS: The choice of surgical operations on ossifying fibroma of the sinuses was mainly decided by the location of ossifying fibroma, in the meanwhile, the organ function, the cosmetology, the surgical degree of difficulty, and the doctor's experience were taken into account.