Publications by authors named "Yüksel Sahin"

15 Publications

  • Page 1 of 1

1,2-Diborolanes with strong donor substituents: Synthesis and high antimicrobial activity.

Bioorg Chem 2021 Jan 21;106:104494. Epub 2020 Nov 21.

Department of Physics, Faculty of Science, Dokuz Eylül University, 35160 İzmir, Turkey.

1,2-diborolanes with strong and without strong donor substituents have been described, and are also referred to as 1,2-diboracyclopentane. The 1,2-diaryl/alkyl-amino-1,2-diboracyclopentanes 2, 3, and 4 were obtained in good yield after the reaction of 1,2-dichloro-1,2-diboracyclopentane 1 with ArNHLi and MeSi-NR. The structures of these new derivatives were characterized by nuclear magnetic resonance spectroscopy. The molecular structures of 2b, 2c, 2e, 4, and 5f were also determined by single-crystal X-ray diffraction. The newly synthesized 1,2-borolanes are stable in air and showed particularly high activity against some Gram-positive bacteria.
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http://dx.doi.org/10.1016/j.bioorg.2020.104494DOI Listing
January 2021

Neutral cyclic sp-sp and sp-sp diboranes from ,'-dicyclohexylcarbodiimide insertion into 1,2-dichlorodiboranes(4).

Chem Commun (Camb) 2020 Aug;56(68):9807-9810

Department of Chemistry, Science and Art Faculty, Aydın Adnan Menderes University, Aydın, Turkey.

We report the synthesis and structural characterization of new neutral cyclic sp2-sp3 and sp3-sp3 diboranes from the reaction of N,N'-dicyclohexylcarbodiimide with 1,2-dichlorodiboranes(4) at room temperature. The present study is the first example of an insertion reaction of carbodiimide into diborane(4).
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http://dx.doi.org/10.1039/d0cc03454aDOI Listing
August 2020

One of the giants of neurological surgery left us more than a decade ago, and neurosurgical literature did not show much interest.

Neurol Neurochir Pol 2011 Jan-Feb;45(1):63-7

Tophane Mahallesi, Laleli Sok, Yilmaz Apt 14/3, 53100 Merkez-Rize, Turkey.

One of the giants of neurological surgery left us over a decade ago. Charles George Drake died September 15, 1998 in London, Ontario after an extended bout with lung cancer. Although he will always be identified with taking posterior fossa aneurysm surgery from the realm of the daring to the domain of the routine, his contributions were much broader. Clinical neurosciences have been blessed in the past century by the life and works of Drake. In the neurosurgical world, the achievements of Drake are very well known and have been well recorded. Unfortunately, in the past decade since his passing, only one paper has been published about him and his contributions to neurosurgery. This is a historical paper regarding Charles George Drake that attempts to (1) remember Drake as a pioneer; (2) to evaluate lessons that we have learned from him; and (3) to address the question 'What made him great?'. As per Drake's teachings, this paper is meant to articulate the unique perspectives Charlie provided with respect to how we learn our craft, maintain the integrity of reporting, and implement suggestions as to how we may progress into the future. In conclusion, it is our hope that this paper will bring to life the unique character of Drake and his unprecedented blend of genius, creativity, technical skill, introspection, and ever-present humility for all international neurosurgeons to appreciate.
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http://dx.doi.org/10.1016/s0028-3843(14)60061-xDOI Listing
September 2011

A practical synthesis of novel α-dibromoalkyl- and trimethylsilylmethyl-aminoboranes and derivatives.

Spectrochim Acta A Mol Biomol Spectrosc 2011 Mar 24;78(3):1139-42. Epub 2010 Dec 24.

Adnan Menderes University, Department of Chemistry, Aydın, Turkey.

Addition of LDA to a mixture of trimethylborate and dibromomethane in THF at a temperature of -78°C leads to the formation of dibromomethyllithium and its capture by borate ester. ClB(OMe)(2) converts the resulting borate salt to dimethoxy(dibromomethyl)borane 2. N,N-Dimethylamino(methoxy)(dibromomethyl)borane 3 and N,N-bis(dimethylamino)(dibromomethyl)borane 4 were prepared by an amination reaction between N,N-dimethylaminotrimethylsilane and dimethoxy(dibromomethyl)borane 2. To obtain dichlorotrimethylsilylmethylborane 7 not containing the α-halomethyl group, N,N-bis(dimethylamino)(trimethylsilylmethyl)borane 5 was first obtained from the reaction of ClB(NMe(2))(2) with an organolithium reagent. Dimethoxy(trimethylsilylmethyl)borane 6 was then prepared by methoxylation of compound 5. Finally, compound 7 was prepared by chlorination of 6 using BCl(3). The chemical structures of these compounds were determined using (13)C, (1)H, (11)B NMR and GC/MS/MS techniques.
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http://dx.doi.org/10.1016/j.saa.2010.12.066DOI Listing
March 2011

Isolated posterior spinal artery aneurysm causing intracranial acute subarachnoidal hemorrhage.

Acta Neurochir (Wien) 2010 Apr 20;152(4):721-4. Epub 2009 Aug 20.

Clinic of Neurosurgery, Sişli Etfal Education and Research Hospital, Istanbul 34077, Turkey.

A case of an isolated posterior spinal artery aneurysm of the upper cervical spinal cord is presented. Spinal artery aneurysms that are not associated with other entities are extremely rare. Four cases have been reported in the literature to date. The patient developed symptoms and signs of intracranial subarachnoid hemorrhage. The aneurysm was successfully clipped. No other vascular abnormalities were seen.
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http://dx.doi.org/10.1007/s00701-009-0491-2DOI Listing
April 2010

Transsellar transsphenoidal rhino-oral encephalocele.

Turk Neurosurg 2007 Oct;17(4):264-8

Sişli Etfal Education and Research Hospital, Neurosurgery Clinic, Istanbul, Turkey.

Transsphenoidal encephaloceles are rare and the transsellar variety is the least common. We present a 1-year-old male patient with transsellar transsphenoidal encephalocele which herniated into the oral cavity through the congenital split palate. The patient was operated on using a combined transcranial and transpalatal approach without mortality or permanent morbidity. Clinical findings, imaging reviews, surgical repair techniques and postoperative morbidity are discussed with the relevant literature. We conclude that repair of a transsphenoidal encephalocele should be coordinated between a team of neurosurgeons and otorhinolaryngologists. Our surgical outcome supports a transcranial approach for the treatment of these difficult lesions, with transpalatal dissection and exposure.
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October 2007

Efficacy of unilateral laminectomy for bilateral decompression in lumbar spinal stenosis.

Turk Neurosurg 2007 Apr;17(2):100-8

Sişli Etfal Training and Research Hospital, Neurosurgery Clinic, Istanbul, Turkey.

Objective: We have conducted a prospective study to evaluate the results and effectiveness of bilateral decompression via a unilateral laminectomy in 50 patients with 98 levels of degenerative lumbar spinal stenosis without instability.

Methods: Clinical outcomes were assessed using the Visual Analog Scale, Oswestry Disability Index, Short Form-36, and subjective Satisfaction Measurement.

Results: Adequate decompression was achieved in all patients. The mean follow-up time was 22.8 months (range 19 - 47 months). Surgical decompression resulted in a dramatic reduction of overall pain in all patients (late postoperative VAS score was 2.16 +/- 0.81). The ODI scores decreased significantly in early and late follow-up evaluations and the SF-36 scores demonstrated significant improvement in late follow-up results in our series. Patient satisfaction rate was 94%, and its improvement rate was 96%.

Conclusion: For degenerative lumbar spinal stenosis with or without mild degenerative spondylolisthesis, the unilateral approach allowed sufficient and safe decompression of the neural structures and adequate preservation of vertebral stability, resulted in a highly significant reduction of symptoms and disability, and improved health-related quality of life.
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April 2007

The effects on prognosis of surgical treatment of hypertensive putaminal hematomas through transsylvian transinsular approach.

Surg Neurol 2003 Mar;59(3):176-83; discussion 183

Department of Neurosurgery, Sişli Etfal State Hospital, Göktürk Cad., Samat apt No: 46/14, Göktürk/Kemerburgaz, Istanbul, Turkey

Objective: Hypertensive putaminal hematoma (HPH) is a devastating type of stroke that mostly results in death or severe neurologic deficit. There seems to be no general agreement on the selection of treatment modality for individual patients. In this study a comparison has been made between conservative treatment and the results of surgical treatment through the transsylvian transinsular approach of HPH with 30 cc or more.

Methods: Sixty-six patients with 30 cc volume or over of HPH, who were admitted within 36 hours after ictus, have been included in this study. Selection of the patients was made primarily according to the computerized tomography scan (CT) findings on admission. Out of the 66 patients, 47 were operated for hematoma evacuation through transsylvian transinsular approach, and the remaining 19 were accepted as a control group to be treated conservatively after their relatives declined authorization for surgery. All patients' neurologic grades and CT findings on admission were classified according to the hypertensive intracerebral hemorrhage grading system, as proposed by the cooperative study in Japan. After 6 months the outcomes of both groups were assessed according to the Glasgow outcome scale (GOS).

Results: The statistical difference between the mortality rates was considerable (p < 0.05) with ratios of 34% and 63.1% in the surgically and conservatively treated groups, respectively. Good recovery, that is GOS score 5, was not observed in either group. In the group of surgically treated patients, 27.7% was eventually moderately disabled (GOS score 4); whereas this ratio was 5.3% among the conservatively treated group, giving a statistically significant difference (p < 0.05). Our results indicate that neurologic grades and CT findings on admission are good predictors of outcome, as the grades increase the outcome worsens. Furthermore, ventricular spread of hematoma is not a good prognostic factor.

Conclusions: Surgical treatment via transsylvian transinsular approach of HPH with a volume of 30 cc or more results in improved outcome as compared to conservative treatment. Operation time within the first 36 hours after ictus did not affect the outcome.
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http://dx.doi.org/10.1016/s0090-3019(02)01043-1DOI Listing
March 2003

Triboracyclopropanates: two-electron double aromatic compounds with very short B-B distances.

Angew Chem Int Ed Engl 2002 Sep;41(18):3380-2

Fachbereich Chemie, Universität Marburg, Hans-Meerwein-Strasse, 35032 Marburg, Germany.

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http://dx.doi.org/10.1002/1521-3773(20020916)41:18<3380::AID-ANIE3380>3.0.CO;2-8DOI Listing
September 2002

Clinical and radiological results of lumbar microdiskectomy technique with preserving of ligamentum flavum comparing to the standard microdiskectomy technique.

Surg Neurol 2002 Jan;57(1):5-13; discussion 13-4

Sişli Etfal Hospital, Department of Neurosurgery, Istanbul, Turkey.

Background: The ligamentum flavum is the anatomic plane between the epidural and laminar-extralaminar spaces, which should be meticulously preserved for a possible reoperation. Preservation of the ligamentum flavum together with other epidural anatomic structures, such as epidural fat tissue and venous plexuses, and limited removal of the lamina are important components in preventing epidural fibrosis that may be the cause of failed back surgery syndrome.

Methods: One thousand five hundred patients underwent microdiskectomy with preservation of the ligamentum flavum over an 8-year period. This technique was performed with a small incision using an 18 mm-width mini Taylor retractor. The ligamentum flavum was released and preserved as a 3-sided flap. The disk content was totally removed and a pediculated fat graft was used to cover the root at the end. Four hundred patients operated on with the ligamentum flavum preserving technique were randomly selected for this study (Group 1). Their results were compared with those of 200 patients who were operated on with the standard microdiskectomy (Group 2). Standard microdiskectomy technique was performed with fenestration and foraminotomy and the ligamentum flavum was partially or totally excised. Early clinical outcome was classified as excellent, good, fair, poor, or failure. The clinical mean follow-up period in Group 1 was 36.8 months and in Group 2 it was 32.4 months. One hundred patients from each group had computed tomographic scans with contrast administration performed at least one year after the operation to examine late epidural fibrosis. A questionnaire was given to all patients at least 3 times during the late follow-up period. The questionnaire required patients to describe their relief of pain, job performance, and abstinence from narcotic analgesic use.

Results: Early clinical outcome (fourth postoperative week) in Group 1 was satisfactory in 96.75% of the patients, whereas it was satisfactory in only 81.5% in Group 2 (p < 0.001). The radiological examinations revealed fibrosis in 18% of the patients in Group 1 and 37% in Group 2 (p < 0.001). None of the patients in Group 1 were readmitted because of fibrosis-related symptoms. The reoperation rate in Group 1 was 4.5%. The recurrence rate was 1.75% and disc at another level was 2.5%. One patient was reoperated because of a suture granuloma. In Group 2, the reoperation rate was 9% (p < 0.05). The recurrence rate was 4.5%, disc at another level was 3.5% and extensive epidural fibrosis was 1%. Two patients who underwent surgery for epidural fibrosis in this group had disappointing outcomes. Overall success rate based on the questionnaire was 91% in Group 1 and 76% in Group 2 (p < 0.001).

Conclusions: The ligamentum flavum preserving technique is useful in achieving a favorable long-term outcome, and reoperation, if necessary, is easier and safer.
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http://dx.doi.org/10.1016/s0090-3019(01)00677-2DOI Listing
January 2002

Nonorthogonal Dilithium-1,3-biborataallenes Containing Planar-Tetracoordinate Carbon Atoms.

Angew Chem Int Ed Engl 2001 Jul;40(14):2662-2665

Fachbereich Chemie der Universität Marburg 35032 Marburg Fax: (+49) 6421-2828917.

Deviations of up to 36° from the orthogonality of the planes of the terminal B atoms of the allene skeleton and their neighbors (ipso-C atoms) are observed in tetraaryl-1,3-diborataallenes of contact-ion triples 1. The unusual geometries are caused by steric hindrance between ortho-methyl groups, which is induced by interactions of the lithium counterions with the π electrons of the aryl substituents, as well as by small barriers to planarization of 1,3-diborataallenes. Ar=for example, 2,3,5,6-tetramethylphenyl.
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http://dx.doi.org/10.1002/1521-3773(20010716)40:14<2662::AID-ANIE2662>3.0.CO;2-VDOI Listing
July 2001