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Schick B, Kronsbein H, Loewenhardt B. [Unusual submandibular tumor transformation. Myoepithelial carcinoma in a pleomorphic adenoma of the submandibular gland]. HNO 2000; 48:784-5. [PMID: 11103354 DOI: 10.1007/s001060050661] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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77
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Schick B, Brors D, Arps H. [Bilateral laryngeal pouch tumor. Localized amyloidosis of the larynx]. HNO 2000; 48:152-3. [PMID: 10663065 DOI: 10.1007/s001060050024] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
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78
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Schick B, el Rahman el Tahan A, Brors D, Kahle G, Draf W. Experiences with endonasal surgery in angiofibroma. Rhinology 1999; 37:80-5. [PMID: 10416254] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/13/2023]
Abstract
Surgery is the most common treatment for angiofibromas, but the approach is still a major point of discussion. Five cases of angiofibroma with typical localisation were treated surgically by an endonasal approach at the Fulda Academic Teaching Hospital from 1994 to 1997. This article presents an analysis of the clinical findings, computer tomography and magnetic resonance imaging, preoperative embolization, operative technique and complications. Endoscopic and radiologic follow-up ranging from 5 to 39 months excluded any residual tumour or recurrence. The endonasal microendoscopic approach with adequate preoperative embolization should be considered as an useful technique for removing tumours with considerable size without using an external incision.
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Relic A, Schick B, Kronsbein H, Kahle G, Draf W. [Bone neogenesis in a rare space-occupying lesion of the inner ear canal]. HNO 1999; 47:563-8. [PMID: 10427527 DOI: 10.1007/s001060050425] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/28/2022]
Abstract
Hemangiomas of the skull base are rare neoplasms and are easily misdiagnosed as acoustic neuromas when occurring in the internal auditory canal. Among these tumors, ossifying hemangiomas are characterized histologically be newly formed bone tissue within their substance. We describe a 26-year old female patient who presented with left-sided sensorineural hearing loss and tinnitus. T2-weighted magnetic resonance imaging demonstrated a bright space-occupying lesion of the internal auditory canal with extension to the geniculate ganglion. Bony erosions of the internal auditory canal were proved by high-resolution computed tomography. A hemangioma was suspected preoperatively and was resected via a middle cranial fossa approach. Histologically, new bone formations were found in a cavernous hemangioma. In general, radiologic findings can suggest a hemangioma of the internal auditory canal and help to differentiate it from acoustic neuroma. Based on the histological findings of intratumoral bone formation, the hemangioma in our patient was classified as an ossifying hemangioma. However, reactive bone formation at the borders of a tumor in the internal auditory canal can also be mistaken as new intratumoral bone formation.
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Weber R, Keerl R, Radziwill R, Schick B, Jaspersen D, Dshambazov K, Mlynski G, Draf W. Videoendoscopic analysis of nasal steroid distribution. Rhinology 1999; 37:69-73. [PMID: 10416252] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/13/2023]
Abstract
Topical corticosteroids are one of the main pillars in the treatment of nasal polyps. The exact topography of their intranasal deposition has not yet been adequately visualised. The intranasal distribution of a 1% sodium fluorescein solution applied with original Pulmicort Topinasal (budesonide) metered pump bottles was analysed by videoendoscopy. The study group included eight healthy subjects and ten patients who had undergone endonasal sinus surgery. Videoendoscopy was performed in the study group within the first minute after application of the fluorescein solution. Additionally the deposition pattern of Pulmicort Topinasal was analyzed using a nasal model. The examination showed that the majority of the substance is deposited on the anterior portion of the nasal septum and the head of the inferior turbinate. Only a small fraction actually reaches the middle meatus. The distribution is improved by application during the decongested phase of the nasal cycle, after use of vasoconstricting nasal drops and maintaining a spraying angle of 45 degrees upwards. The development of new delivery techniques and systems could improve the efficacy of intranasally administered corticosteroids and reduce the complication rate.
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Abstract
Beckwith-Wiedemann syndrome is a rare genetic overgrowth syndrome presenting with organomegaly, abdominal wall defects, macroglossia, and postnatal hypoglycemia. Head and neck manifestations of this abnormality include flame nevus of the forehead and characteristic sulci of the ear lobe. We present a 7-year-old child with Beckwith-Wiedemann syndrome and a rare finding of conductive hearing loss on both sides due to congenital malleus and stapedial fixation. Small fenestra stapedotomy and mobilization of malleus fixation in the epitympanum improved the child's hearing. The bony fixation of the malleus and stapes is explained as atavism of the processus anterior mallei and peripheral lamina stapedialis in embryological development.
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Abstract
Hemangiopericytomas are mesenchymal tumors and account for about 1% of all CNS tumors. Aggressive growth, tendency to local recurrence and relatively frequent metastases are the clinical features of these tumors. Histological characteristics are marked cellularity, vascularity and a dense net of reticular fibers. This case presents a patient with a local recurrence of a right temporal, atypical meningioma that had been operated on and irradiated elsewhere. After embolization large parts of the tumor were removed palliatively. Histological aspects of the resected tumor were consistent with a diagnosis of an atypical meningioma. Not until hepatic metastases from this tumor were found was the diagnosis re-examined and corrected to a malignant meningeal hemangiopericytoma. Surgical resection of primary tumor with frequent controls and, if needed, postoperative radiation therapy is the treatment of choice. Furthermore metastasizing atypical meningiomas should be examined critically to determine if a hemangiopericytoma is present.
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Einarson A, Phillips E, Mawji F, D'Alimonte D, Schick B, Addis A, Mastroiacova P, Mazzone T, Matsui D, Koren G. A prospective controlled multicentre study of clarithromycin in pregnancy. Am J Perinatol 1999; 15:523-5. [PMID: 9890248 DOI: 10.1055/s-2007-994053] [Citation(s) in RCA: 77] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
Abstract
Clarithromycin is a relatively new macrolide antibiotic with an action spectrum similar to that of erythromycin. Its main indications for use are for upper and lower respiratory and skin and soft tissue infections. Little is known about its safety in pregnancy, although animal reproductive studies found an increased rate of cardiovascular anomalies, cleft palate, and embryonic loss. Human data, limited to case reports and one small uncontrolled study, cannot allow evidence based counseling of pregnant women who were exposed to the drug before finding out they were pregnant. Pregnant women who had been counseled on the use of clarithromycin by five centers, were matched for age, smoking, and alcohol use with a control group of pregnant women who were exposed to nonteratogenic antibiotics. A total of 157 women were followed up. Of these, 122 were exposed to the drug in the first trimester. There were no significant differences found between the two groups in the rates of major and minor malformations; 2.3 versus 1.4% for major (p = 0.86) and 5.4 versus 4.9% for minor (p = 0.96). Spontaneous abortion rates in the exposed group was significantly different, higher (14%) than in the control group (7%) (p = 0.04). This first prospective controlled study of exposure to clarithromycin in pregnancy suggests that this agent does not increase the rate of major malformations above the baseline risk of 1-3%. The higher rate of reported spontaneous abortions, although still within the expected baseline rate, may warrant further study.
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85
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Schick B, Williams K, Bolster L. Skill levels of educational interpreters working in public schools. JOURNAL OF DEAF STUDIES AND DEAF EDUCATION 1999; 4:144-155. [PMID: 15579883 DOI: 10.1093/deafed/4.2.144] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
The Educational Interpreter Performance Assessment, or EIPA, is an evaluation tool designed specifically for educational interpreters. An evaluation using the EIPA considers the child's grade level, the sign language or sign system that the interpreter is using as well as any other child-specific factors. Fifty-nine educational interpreters were evaluated using the EIPA. They had different backgrounds and training, and used different types of sign language or sign language or sign systems. The results show that not all of the educational interpreters were qualified to provide a child with an adequate interpretation of classroom discourse. Less than half of the educational interpreters assessed in this study performed at a level considered minimally acceptable. These data also show that sign vocabulary skills were significantly better than grammatical skills. Eighteen interpreters were evaluated twice in order to test-retest reliability, which showed that scores were not significantly different between the two evaluations. The picture that emerges from these data is that many deaf children receive an interpretation of classroom discourse that may distort and inadequately represent the information being communicated.
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Abstract
A rare case of an unusual sinus within the styloid process is described. The radiological appearance of this malformation is presented with CT-scans and a hypothesis for its development is presented. The malformation is designated as "Recessus processus styloidei" and this entity is considered to be a dysgenesis of the second branchial arch.
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87
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Abstract
The case of a 50-year-old man with an unusual sinus of the styloid process is presented. This anomaly caused recurrent otorrhea and repeated neck inflammation. The sinus was identified in the upper part of the styloid process and was resected completely as definitive treatment. Since the styloid process is formed by mesenchymal tissue of the second branchial arch, lack of chondrification and ossification was presumed to be the cause of the sinus found in the patient. In case of direct communication between the styloid process cavity and the middle ear space the term "styloid process recess" is suggested. This recess can act as a possible source for recurrent middle ear infections and neck inflammations.
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88
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Schick B, Brors D, Goedecke A, Prescher A, Draf W. Detection of an occult transclival cerebrospinal fluid fistula by CT and MRI. Neuroradiology 1998; 40:797-9. [PMID: 9877134 DOI: 10.1007/s002340050687] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
We describe an unusual occult transclival cerebrospinal fluid (CSF) fistula to the sphenoid sinus demonstrated by MRI. CT was performed because of a posterior cerebral infarct caused by cardiac arrhythmia. Axial sections showed fluid in the sphenoid sinus. High-resolution scans revealed a bony defect 3 mm in diameter of the posterior wall of the sphenoid sinus, and MRI showed a transclival CSF fistula. This occult lesion was confirmed by surgery and duraplasty was successfully performed via an endonasal approach.
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Schauss F, Schick B, Draf W. [Regional muscle flap-plasty and adjuvant measures for rehabilitation of the paralyzed face]. Laryngorhinootologie 1998; 77:576-81. [PMID: 9842522 DOI: 10.1055/s-2007-997029] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
Abstract
BACKGROUND The loss of facial nerve activity reduces the quality of life in regard to functional disturbances and to the appearance of the patient. As far as possible a reconstruction of the facial nerve should be advocated. Only this procedure allows the natural variety of differentiated facial expression. If reconstruction of the facial nerve is not indicated or turns out to be unsatisfactory, a dynamic muscle transposition should be considered. PATIENTS AND METHODS The patient records of the ENT-Departments in Fulda for the period from 1988 to 1995 and in Mönchengladbach from 1993 to 1995 were reviewed to survey the experience of secondary plastic rehabilitation of the paralysed face. Our special interest focussed on the oral region with dynamic muscle transfer. The techniques leading to rehabilitation of the lid region were included in this study. RESULTS Transfer of the temporalis muscle was performed 12 times and a masseter muscle flap 4 times to rehabilitate the oral region. Static rehabilitation (canthoplasty, tarsorrhaphy) of the lid was performed 8 times, implantation of a gold weight in the upper lid 5 times and dynamic rehabilitation of the lid region with a temporalis muscle transposition once. CONCLUSIONS Rehabilitation of the oral region is best managed with a temporalis muscle flap because of its favourable vector of tension and its broad, flat form. Masseter muscle transposition is particularly indicated if a temporalis muscle transfer is not possible or if resection of the facial nerve because of malignancy of the parotid gland has to be performed and nerve reconstruction is not advisable.
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90
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Schick B, Draf W, Kahle G. [Jugulotympanic paraganglioma: therapy concepts under development]. Laryngorhinootologie 1998; 77:434-43. [PMID: 9760423 DOI: 10.1055/s-2007-997004] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
Abstract
BACKGROUND The operative treatment and radiation therapy of jugulotympanic paragangliomas (JTP) are still a matter of controversial discussion. In spite of various improvements during the last 50 years, selecting the appropriate treatment modality (surgery, radiation, or observation) is still a challenge. PATIENTS During a 16-year period, 44 patients with 45 JTP (10 at level A/B and 35 at level C/D according to Fisch) were seen at the ENT-department in Fulda. Forty-one cases were treated surgically. RESULTS Complete resection was possible for level A/B in 100% of the patients (n = 10). Residual tumor was demonstrated for level C in 23% of the patients (5/22) and for level D in 40% (4/10) with a median follow-up time of 69 months. In two cases residual tumor was treated by radiation. Six patients with residual paraganglioma tissue were maintained under observation without any evidence of tumor progression (median follow-up time 39 months). We report one death after the attempt to resect a large residual paraganglioma that had already caused brain stem compression. A sufficient duraplasty could not be achieved following radiation therapy. CONCLUSIONS Complete tumor resection of jugulotympanic paragangliomas of levels A and B is often possible without injury to the cranial nerves. Extensive tumors present difficulties in complete tumor resection and increase the risk of cranial nerve injuries. Advanced paragangliomas therefore require an individualized therapeutic regime including surgery, radiation therapy, and observation of tumor growth.
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91
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Shuhaiber S, Pastuszak A, Schick B, Matsui D, Spivey G, Brochu J, Koren G. Pregnancy outcome following first trimester exposure to sumatriptan. Neurology 1998; 51:581-3. [PMID: 9710039 DOI: 10.1212/wnl.51.2.581] [Citation(s) in RCA: 64] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
We prospectively compared pregnancy outcome after exposure to sumatriptan with that of disease-matched controls and nonteratogen controls. There were no differences in the rates of live births, spontaneous abortions, therapeutic abortions, or major birth defects among the three groups. This first prospective report suggests that the use of sumatriptan during organogenesis is not associated with an apparent increased risk of major birth defects.
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92
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Schick B, Hendus J, el Tahan A, Draf W. [Reconstruction of the forehead region with tabula externa of the skull]. Laryngorhinootologie 1998; 77:474-9. [PMID: 9760428 DOI: 10.1055/s-2007-997009] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
Abstract
BACKGROUND Calvarial bone graft is often used in reconstructive cranio-facial surgery. As most common three different forms can be distinguished: outer-table bone, full thickness grafts and composite flaps (bone with a periostal or muscular pedicle). PATIENT AND METHOD An extensive fibrous dysplasia of the frontal region was removed in a 26 years old patient. Reconstruction was carried out with alloplastic material achieving a good esthetic result. Recurrent seroma and occurrence of a fistula demanded removal of the alloplastic material and en-bloc reconstruction of the forehead region was accomplished with a parietal outer-table graft. Within a follow-up time of one year a good esthetic and stable reconstruction has been achieved. CONCLUSION Split-thickness calvarial bone is still a versatile graft in reconstruction of the forehead region. Although a low rate of side effects in harvesting calvarial bone grafts are in general expected, one has to be aware of dural lesions occuring in the donor site during craniotomy.
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93
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Loebstein R, Addis A, Ho E, Andreou R, Sage S, Donnenfeld AE, Schick B, Bonati M, Moretti M, Lalkin A, Pastuszak A, Koren G. Pregnancy outcome following gestational exposure to fluoroquinolones: a multicenter prospective controlled study. Antimicrob Agents Chemother 1998; 42:1336-9. [PMID: 9624471 PMCID: PMC105599 DOI: 10.1128/aac.42.6.1336] [Citation(s) in RCA: 163] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
Concerns regarding the teratogenicity of fluoroquinolones have resulted in their restricted use during gestation. This is despite an increasing need for their use due to emerging bacterial resistance. The objectives of the present investigation were to evaluate pregnancy and fetal outcomes following maternal exposure to fluoroquinolones and to examine whether in utero exposure to quinolones is associated with clinically significant musculoskeletal dysfunctions. We prospectively enrolled and followed up 200 women exposed to fluoroquinolones (norfloxacin, ciprofloxacin, ofloxacin) during gestation. Pregnancy outcome was compared with that for 200 controls matched for age and for smoking and alcohol consumption habits. Controls were exposed to nonteratogenic, nonembryotoxic antimicrobial agents matched by indication, duration of therapy (+/- 3 days), and trimester of exposure. Rates of major congenital malformations did not differ between the group exposed to quinolones in the first trimester (2.2%) and the control group (2.6%) (relative risk, 0.85; 95% confidence interval, 0.21 to 3.49). Women treated with quinolones had a tendency for an increased rate of therapeutic abortions compared with the rate among women exposed to nonteratogens (relative risk, 4.50; 95% confidence interval, 0.98 to 20.57), resulting in lower live-birth rates (86 versus 94%; P = 0.02). The rates of spontaneous abortions, fetal distress, and prematurity and the birth weight did not differ between the groups. Gross motor developmental milestone achievements did not differ between the children of the mothers in the two groups. We concluded that the use of fluoroquinolones during embryogenesis is not associated with an increased risk of major malformations. There were no clinically significant musculoskeletal dysfunctions in children exposed to fluoroquinolones in utero. The higher rate of therapeutic abortions observed in quinolone-exposed women compared to that for their controls may be secondary to the misperception of a major risk related to quinolone use during pregnancy.
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94
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Schick B, Kahle G, Draf W. [Vascular middle ear structure. Ectopic course of the internal carotid artery]. HNO 1998; 46:534-5. [PMID: 9647927 DOI: 10.1007/s001060050264] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
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95
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Schick B, Brors D, Draf W. [Experiences with hemangiopericytoma in cranial base surgery]. Laryngorhinootologie 1998; 77:256-63. [PMID: 9644672 DOI: 10.1055/s-2007-996971] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
BACKGROUND Haemangiopericytomas are rare vascular neoplasms which show either slow local tumour growth or aggressive progression in size with a high tendency of recurrence and metastasis. Manifestations of haemangiopericytomas in the area of the nose and sinuses are supposed to have a relatively benign course. To date clinical and histological parameters for prognosis are uncertain. Therefore in a quite large number of cases only the clinical course allows to evaluate the dignity of a haemangiopericytoma. PATIENTS AND RESULTS We present our experience with five haemanglopericytomas in contact with the skull base out of a total number of 457 skull base tumours. The site of origin of these five haemangiopericytomas were: nasal septum, pterygopalatine fossa, oronasopharynx, temporal bone, and parotid gland. All neoplasms showed primary or recurrent tumor in contact with the skull base and an intracranial extension was observed twice. One patient died postoperatively of a cerebral infarction. Three patients showed one or more recurrences which were treated surgically. In one case 5 recurrences occurred. Despite of 4 surgical procedures within a period of 15 months, the tumour could be controlled only for a short period of time, and the patient died 16 months after the first operation. CONCLUSION One has to consider that haemangiopericytomas of the head and neck show a potential malignant course. The vascular tumor may recur decades later. Adequate therapy and life-long follow-up are therefore mandatory in haemangiopericytomas. Complete surgical resection of the tumour is usually the treatment of choice, in spite of the high degree of surgical skill required, especially in advanced tumour and in case of recurrence.
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Schick B, Kahle G, Weber R, Draf W. [Experiences in diagnosis of occult traumatic dural lesions of the anterior cranial base]. Laryngorhinootologie 1998; 77:144-9. [PMID: 9577820 DOI: 10.1055/s-2007-996949] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
BACKGROUND Meningitis or cerebrospinal fluid rhinorrhea can occur years or even decades after trauma and can be the first indication of a previously unidentified dural lesion. In spite of being difficult, precise localization of an occult traumatic dural lesion is a necessary prerequisite for duraplasty. PATIENTS AND METHODS In a retrospective study covering a period of 17 years, we identified 27 patients with occult traumatic dural lesions. The dural lesions were localized by high-resolution CT, MRI, fluorescein nasal endoscopy, and CT cisternography. In all cases the expected dural lesion was demonstrated and treated surgically. RESULTS In 23 out of 27 patients (85%), the rhinobasal fistula was detected as a bony defect by CT. Furthermore MRI examination in 100% (5/5), a preoperative fluorescein nasal endoscopy in 50% (10/20) and CT cisternography in 56% (5/9) were able to localize the dural lesion. CONCLUSION We recommend high-resolution CT and MRI as diagnostic tools of choice in searching for occult dural lesions. Fluorescein nasal endoscopy and CT cisternography are justified as invasive techniques if CT and MRI are inconclusive but clinically CSF leakage is still suggested. The patient will remain at risk of potentially fatal meningitis until the lesion is appropriately repaired by duraplasty. Therefore modern clinical and radiological diagnostic methods should be used to search for an unknown dural lesion.
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Schick B, Kind M, Draf W, Weber R, Lackmann GM. Extranasopharyngeal angiofibroma in a 15-month-old child. Int J Pediatr Otorhinolaryngol 1998; 43:99-104. [PMID: 9596374 DOI: 10.1016/s0165-5876(98)00020-2] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Angiofibromas are usually characterized by typical location with involvement of the posterior nasal cavity and nasopharynx. They are most commonly found in adolescent males. Despite these facts, a case of an angiofibroma presented in a 15-month-old boy at an atypical site anterior and medial to the lacrimal sac. The tumor was resected via an endonasal, micro-endoscopic approach avoiding an external incision.
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98
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Vitali J, Schick B, Kester HC, Visser J, Jurnak F. The tree-dimensional structure of aspergillus niger pectin lyase B at 1.7-A resolution. PLANT PHYSIOLOGY 1998; 116:69-80. [PMID: 9449837 PMCID: PMC35189 DOI: 10.1104/pp.116.1.69] [Citation(s) in RCA: 69] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/15/1997] [Accepted: 09/19/1997] [Indexed: 05/22/2023]
Abstract
The three-dimensional structure of Aspergillus niger pectin lyase B (PLB) has been determined by crystallographic techniques at a resolution of 1.7 A. The model, with all 359 amino acids and 339 water molecules, refines to a final crystallographic R factor of 16.5%. The polypeptide backbone folds into a large right-handed cylinder, termed a parallel beta helix. Loops of various sizes and conformations protrude from the central helix and probably confer function. The largest loop of 53 residues folds into a small domain consisting of three antiparallel beta strands, one turn of an alpha helix, and one turn of a 3(10) helix. By comparison with the structure of Erwinia chrysanthemi pectate lyase C (PelC), the primary sequence alignment between the pectate and pectin lyase subfamilies has been corrected and the active site region for the pectin lyases deduced. The substrate-binding site in PLB is considerably less hydrophilic than the comparable PelC region and consists of an extensive network of highly conserved Trp and His residues. The PLB structure provides an atomic explanation for the lack of a catalytic requirement for Ca2+ in the pectin lyase family, in contrast to that found in the pectate lyase enzymes. Surprisingly, however, the PLB site analogous to the Ca2+ site in PelC is filled with a positive charge provided by a conserved Arg in the pectin lyases. The significance of the finding with regard to the enzymatic mechanism is discussed.
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Schick B, Kind M, Draf W, Weber R, Lackmann GM. Extranasopharyngeal angiofibroma in a 15-month-old child. Int J Pediatr Otorhinolaryngol 1997; 42:135-40. [PMID: 9692623 DOI: 10.1016/s0165-5876(97)00127-4] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
Angiofibromas are usually characterized by typical location with involvement of the posterior nasal cavity and nasopharynx. They are most commonly found in adolescent males. Despite these facts, a case of an angiofibroma presented in a 15-month-old boy at an atypical site anterior and medial to the lacrimal sac. The tumor was resected via an endonasal, micro-endoscopic approach avoiding an external incision.
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100
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Abstract
Angiofibromas are usually characterized by their occurrences in adolescent males with a typical localization and involvement of the posterior nasal cavity and nasopharynx. Even the suspicion of an extranasopharyngeal angiofibroma or an angiofibroma in young children must be viewed in general with skepticism, although reports of angiofibromas with atypical localizations and manifestations in young children have appeared in the literature. Three cases of this fibro-vascular neoplasm with manifestations in the first decade of life and atypical localizations are presented: (1) an angiofibroma medial to the left lacrimal sac in a 15-month old boy, (2) a right paranasal localization in a 9-year-old boy and (3) an angiofibroma limited to the right sphenoid sinus in a 6-year old boy. In all three cases the neoplasm was resected via an endonasal, micro-endoscopic approach that avoided an external incision. According to the literature and based on our own experiences with typical histological findings in all three cases, the clinician has to be aware that the rare angiofibroma can occur in preadolescent children with atypical localizations. The endonasal surgical approach is without any doubt the least traumatic one and in selected cases allows resection of a circumscribed tumor considering functional and aesthetic aspects.
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