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S Behari

Publications and source records attributed to S Behari.

At least 19 recordsLinked to original sources
PubMed2001

Observation of B --> J/psi K(1)(1270).

We report the first observation of the exclusive decay process B-->J/psi K(1)(1270) using a sample of 11.2M BB macro meson pairs collected in the Belle detector at the KEKB asymmetric energy e(+)e(-) collider. We measure branching fractions of B[B(0)-->J/psi K(0)(1)(1270)] = (1.30+/-0.34+/-0.32) x 10(-3) and B[B(+)-->J/psi K(+)(1)(1270)] = (1.80+/-0.34+/-0.39) x 10(-3), where the first error is statistical and the second is systematic. These modes constitute approximately 15% of the total number of B-->J/psi X decays. No evidence is seen for B-->J/psi K(1)(1400) and we set an upper limit for this branching fraction.

Journal Article↗
PubMed2001

Observation of Cabibbo suppressed B --> D(*)K- decays at Belle.

We report observations of the Cabibbo suppressed decays B-->D((*))K- using a 10.4 fb(-1) data sample accumulated at the Upsilon(4S) resonance with the Belle detector at the KEKB e(+)e(-) storage ring. We find that the ratios of Cabibbo suppressed to Cabibbo favored branching fractions are B(B--->D0K-)/B(B--->D0pi(-)) = 0.079+/-0.009+/-0.006, B(B(0)-->D+K-)/B(B(0)-->D+pi(-)) = 0.068+/-0.015+/-0.007, B(B--->D(*0)K-)/B(B--->D(*0)pi(-)) = 0.078+/-0.019+/-0.009, and B(B(0)-->D(*+)K-)/B(B(0)-->D(*+)pi(-)) = 0.074+/-0.015+/-0.006. These are the first observations of the B-->D+K-, D(*0)K-, and D(*+)K- decay processes.

Journal Article↗
PubMed2001

Observation of large CP violation in the neutral B meson system.

We present a measurement of the standard model CP violation parameter sin2 phi(1) based on a 29.1 fb(-1) data sample collected at the Upsilon(4S) resonance with the Belle detector at the KEKB asymmetric-energy e(+)e(-) collider. One neutral B meson is fully reconstructed as a J/psi K(S), psi(2S)K(S), chi(c1)K(S), eta(c)K(S), J/psi K(L), or J/psi K(*0) decay and the flavor of the accompanying B meson is identified from its decay products. From the asymmetry in the distribution of the time intervals between the two B meson decay points, we determine sin2 phi(1) = 0.99+/-0.14(stat)+/-0.06(syst). We conclude that we have observed CP violation in the neutral B meson system.

Journal Article↗
PubMed2001

Measurement of B(0)(d)-B_(0)(d) mixing rate from the time evolution of dilepton events at the upsilon(4S).

We report a determination of the B(0)(d)-&B_(0)(d) mixing parameter Deltam(d) based on the time evolution of dilepton yields in Upsilon(4S) decays. The measurement is based on a 5.9 fb(-1) data sample collected by the Belle detector at KEKB. The proper-time difference distributions for same-sign and opposite-sign dilepton events are simultaneously fitted to an expression containing Deltam(d) as a free parameter. Using both muons and electrons, we obtain Deltam(d) = 0.463+/-0.008 (stat)+/-0.016 (syst) ps(-1). This is the first determination of Deltam(d) from time evolution measurements at the Upsilon(4S). We also place limits on possible CPT violations.

Journal Article↗
PubMed2001

Measurement of the CP violation parameter sin2 phi(1) in B(0)(d) meson decays.

We present a measurement of the standard model CP violation parameter sin2 phi(1) (also known as sin2beta) based on a 10.5 fb(-1) data sample collected at the Upsilon(4S) resonance with the Belle detector at the KEKB asymmetric e(+)e(-) collider. One neutral B meson is reconstructed in the J/psiK(S), psi(2S)K(S), chi(c1)K(S), eta(c)K(S), J/psiK(L), or J/psipi(0) CP-eigenstate decay channel and the flavor of the accompanying B meson is identified from its charged particle decay products. From the asymmetry in the distribution of the time interval between the two B-meson decay points, we determine sin2 phi(1) = 0.58(+0.32)(-0.34)(stat)+0.09-0.10(syst).

Journal Article↗
PubMed2001

Thoracic myelopathy secondary to ossified ligamentum flavum.

BACKGROUND: Focal ossification of the ligamentum flavum (OLF) forms one of the rare causes of thoracic myelopathy. The lower thoracic spine is most frequently affected and the patients present with initial posterior column disturbances followed by progressively increasing spastic paraparesis. The pathogenesis of OLF has not been conclusively established. METHOD: Five patients with thoracic myelopathy due to OLF underwent decompressive laminectomy and excision of the ligamentum flavum. Their MRI delineated a linear or beak like excrescence, uniformly hypo-intense on T1 and T2 weighted images, situated posterior to the thecal sac. A comparison between the preoperative neurological status and the status at follow-up was done using Harsh's myelopathic grading. FINDING: Decompressive laminectomy followed by the drilling of the OLF and its excision, occasionally along with the adherent outer layer of the dura, resulted in significant improvement in motor weakness and tingling sensations. However, at the last available follow-up, none of the patients had retained their ability to run briskly (grade I) and all of them had residual spasticity. INTERPRETATION: OLF may significantly contribute to a spatial reduction of the thoracic spinal canal resulting in paraparesis. The T2 weighted sagittal image of the magnetic resonance imaging (MRI) is the modality of choice for screening of the longitudinal extent of the OLF. A rapid neurological improvement occurs following decompressive laminectomy and excision of the OLF. However, the persistence of residual spasticity at follow-up may be due to irreversible changes within the cord by the significant thecal compression and the delay between the onset of initial symptoms and signs and surgical decompression.

Adult↗
PubMed2001

Extended frontobasal approach to the skull base.

The extended frontobasal approach provides an adequate midline exposure from the anterior cranial fossa to the sphenoclival region. Between November 1991 and August 1999, 13 patients with extensive anterior and anterolateral skull base tumours extending to supra and parasellar regions, cavernous sinus and sphenoclival regions were operated upon using this approach alone (7 patients) or in combination with subtemporal -infratemporal (4 patients) or transfacial (2 patients) approaches. Gross total excision was performed in 8 patients while in 4 patients with malignant tumours and in a patient with extensive skull base fungal granuloma, only partial excision was possible. Basal repair was performed using pedicled pericranium, temporalis muscle or fascia lata. The complications included increase in the cranial nerve paresis, endophthalmitis, facial oedema, CSF leak, frontal haematoma and internal carotid artery injury. This study reviews the operative technique, the indications and the complications of extended frontobasal approach.

Adult↗
PubMed2000

Extradural meningioma en-plaque of the cervical cord.

A rare case of cervical extradural en-plaque meningothelial meningioma is reported. The magnetic resonance imaging revealed an extradural sheet of tumor encasing the cervical cord from anterior, posterior and right lateral aspects and emerging from the right C3-4 intervertebral foramina. Though a differential diagnosis of lymphoma and tubercular granulation tissue were considered, its isointense intensity patterns on T1 and T2 weighted images and the intratumoral calcification on intrathecal contrast computed tomographic scan suggested a meningioma. At surgery, the lesion was fibrous, avascular and densely adherent to the dura. The radiological features and management options of the lesion are discussed.

Adult↗
PubMed2000

C1-C2 rotary subluxation following posterior stabilization for congenital atlantoaxial dislocation.

The authors report a rare complication of C1-C2 rotary subluxation in two children following posterior stabilization for congenital atlantoaxial dislocation (AAD). A patient, with mobile AAD, underwent Brook's C1-C2 fusion while the other, with fixed AAD, underwent transoral decompression followed by Jain's occipitocervical fusion. A pre-existing ligamentous laxity associated with an asymmetrical wire tightening or slippage of the wires due to rotation of the neck in the former, and the drilling of the C1-C2 lateral joints during the transoral procedure in the latter, could have contributed to the rotary subluxation. Both patients presented with persistent torticollis due to fusion in an asymmetrical position with dislocated facet joints. Rotary C1-C2 subluxation, when coexisting with anterior dislocation, has the potential to cause severe and occasionally fatal cord compression. Well defined criteria to diagnose this entity by conventional radiology exist, however, due to the overlap of anatomy, the condition is often overlooked. In the present study, three dimensional reconstruction images using helical computerized tomography were very useful in delineating the subluxation and in planning its surgical reduction and arthrodesis.

Adolescent↗
PubMed1999

Idiopathic hypertrophic cranial pachymeningitis: clinicoradiological spectrum and therapeutic options.

OBJECTIVE: Idiopathic hypertrophic cranial pachymeningitis is a rare disease, of undetermined pathogenesis, that is characterized by inflammation and fibrosis of the dura mater. METHODS: We encountered six patients with idiopathic hypertrophic cranial pachymeningitis and analyzed their clinical presentations, radiological findings, and treatment. RESULTS: In the six patients, the main manifestations were cranial nerve palsies and headache. Three associations were present, namely optic neuropathy, Tolosa-Hunt syndrome, and diabetes insipidus. Gadolinium-enhanced magnetic resonance imaging was diagnostic, showing intense dural enhancement in a linear or nodular pattern. The responses to corticosteroid therapy were better for patients who exhibited linear, rather than nodular, dural enhancement. For one patient, surgical decompression of the superior orbital fissure provided lasting relief. The course of the disease followed one of three patterns, i.e., sustained remission, relapse with corticosteroid independence, or relapse with corticosteroid dependence. Pulse corticosteroid therapy provided significant relief, while reducing the daily corticosteroid requirement and avoiding side effects, for a corticosteroid-dependent relapsing patient. CONCLUSION: Idiopathic hypertrophic cranial pachymeningitis exhibits varied clinical courses. It is important to prevent irreversible cranial neuropathy during the active phase of the disease, using daily administration of corticosteroids, pulse corticosteroid therapy, or surgical decompression.

Adrenal Cortex Hormones↗
PubMed1999

Extreme lateral transcondylar approach to the skull base.

In this study, the authors present their experience of using extreme later transcondylar approach (ELTC) for treating 7 patients with lesions in the anterolateral foramen magnum, upper cervical spine and cerebellopontine angle reaching upto jugular foramen. The tumours included meningiomas, neurofibromas (2 cases each), chondrosarcoma, epidermoid and aneurysmal bone cyst (one case each). The approach was used alone, in combination with retrolabyrinthine presigmoid approach in a patient with lower cranial nerve neurofibroma extending extracranially through the jugular foramen, or in combination with partial C1-C3 laminectomy in two patients with meningiomas situated anterolateral to the cord from the foramen magnum to C3. In two patients with extradural vertebral artery (VA) entrapment by a chondrosarcoma and aneurysmal bone cyst respectively, the vertebral artery was ligated distal to the tumour. The tumours were totally excised in five cases and partially in two. There was no preoperative mortality. The major complications included cerebrospinal fluid leak from the wound (3 cases) and increase in lower cranial nerve paresis (2 cases). At follow up, ranging from 6 months to 2 years, 5 patients showed no tumour recurrence. There was improvement in neurological status. One patient, with a partially excised aneurysmal bone cyst, showed no added deficits or increase in the tumour size. However, there was a massive regrowth in the patient with chondrosarcoma after 6 months. This technique provided a wide surgical exposure with direct visualization of the tumour-anterior cord interface, early proximal control of the VA and preservation of lower cranial nerves.

Adolescent↗
PubMed1999

Transoral decompression for craniovertebral osseous anomalies: perioperative management dilemmas.

The surgical outcome of 74 patients, who underwent transoral decompression (TOD) for ventral irreducible craniovertebral junction anomalies between January 1989 to September 1997, was studied to evaluate the perioperative complications and problems encountered. The indications for TOD included irreducible atlantoaxial dislocation (n=24), basilar invagination (n=16), and a combination of both (n=35). Following TOD, occipitocervical stabilization using Jain's technique was carried out in 50 (67.5%) and atlantoaxial fusion using Brooks' construct in 18 (24.3%) patients. The pre- and postoperative radiology was compared to assess the adequacy of decompression and stability. The major morbidity included pharyngeal wound sepsis leading to dehiscence (20.3%) and haemorrhage (4%), valopharyngeal insufficiency (8.1%), CSF leak (6.7%) and inadequate decompression (6.7%). Neurological deterioration occurred transiently in 17 (22.9%) and was sustained in 7 (9.4%) patients. The mortality in six cases was due to operative trauma, exanguination from pharyngeal wound (one each), postoperative instability and inability to be weaned off from the ventilator (two each). Of the 47 (63.5%) patients available at follow up ranging from 3 months to 2 years, 26 (55.3%) showed improvement from their preoperative status while 14 (29.8%) demonstrated stabilization of their neurological deficits. Seven (14.9%) of them deteriorated. Though TOD is logical and effective in relieving ventral compression due to craniovertebral junction anomalies, it carries the formidable risks of instability, incomplete decompression, neurological deterioration, CSF leak, infection and palatopharyngeal dysfunction.

Adolescent↗
PubMed1999

Peduncular hallucinosis: an unusual sequel to surgical intervention in the suprasellar region.

Peduncular hallucinations are formed visual images often associated with sleep disturbance, and are caused by lesions in the midbrain, pons and diencephalon. In the present study, we report two patients who developed peduncular hallucinations following surgery in the suprasellar region. In one of these, the peduncular hallucinations were a sequel to endoscopic third ventriculostomy, while in the other, they were due to diencephalon and mid-brain compression by a postoperative clot following excision of a hypothalamic astrocytoma.

Astrocytoma↗
PubMed1997

Corpectomy for multi-level cervical spondylosis and ossification of the posterior longitudinal ligament.

The choice of a surgical approach for multi-level cervical spondylotic myelopathy (CSM) and ossification of the posterior longitudinal ligament (OPLL) is still a controversial issue. While most of the surgeons are still performing decompression by laminectomy, some are doing multi-level anterior decompression. Few neurosurgeons are performing decompression by corpectomy. We have treated 26 patients by median cervical corpectomy during the last 4 years. These patients were followed up for a mean period of 25 months. Twenty one (80%) patients had a good outcome, 2 patients remained unchanged and 3 expired. Review of the literature and our experience indicates that patients with CSM and OPLL should be operated by median cervical corpectomy (anterior approach).

Adult↗
PubMed1997

Multiple infected extradural parasellar hydatid cysts.

BACKGROUND: Intracranial hydatid disease constitutes 1%-2% of all cases of hydatid disease. Multiple, infected, extradural, parasellar hydatid cysts in a patient constitutes an extremely rare presentation. CASE REPORT: This 21-year-old man presented with a progressive left supraclavicular swelling of 3 years duration and raised intracranial pressure of 6 months duration with a past history of left-sided chronic suppurative otitis media that had resolved with antibiotics. On neurologic examination, he had bilateral deterioration of vision with optic atrophy; right temporal field defect; left III, IV, VI, VI, and V2 cranial nerves palsy; and left ear conductive deafness. The patient's E.S.R was raised. His computed tomography (CT) scan showed a hypodense, lobulated lesion in the middle cranial fossa with a hypodense, nonenhancing rim, septations, and focal calcification without perifocal edema. A purulent fluid was aspirated from the left supraclavicular swelling, which did not reveal any organism on staining and culture. Aspiration of the left temporal swelling showed whitish watery fluid, the cytology of which revealed an infected hydatid cyst. Excision of the left temporal extradural, hydatid cysts was done, except the portion of the capsule adherent to the dura, and albendazole was started. One month later, the supraclavicular hydatid cysts were removed. Six months later, a left mastoidectomy was performed for chronic suppurative otitis media. A repeat CT scan showed complete resolution of the hydatid cysts. There was no recurrence at 1 year follow-up. CONCLUSIONS: A rare case of multiple infected extradural hydatid cysts of the parasellar region is reported. The unusual CT picture of a hypodense lobulated mass with septations and a hyperdense rims is presented. The difficulties in its complete excision and successful management with long-term albendazole therapy are discussed.

Adult↗
PubMed1997

Problems in differentiating intradural lipoma from dermoid on magnetic resonance imaging.

Spinal intradural subpial lipomas are rare lesions. This case report emphasizes the role of MRI in diagnosing this lesion and in delineating its location. However, a dermoid cyst with a high lipid content of mixed triglycerides and unsaturated fatty acids without cholesterol may present the same appearance as an intradural lipoma and cannot be differentiated from it even with the use of short T1 inversion-recovery (STIR) images.

Adult↗
PubMed1996

Spinal segmental maldevelopment with a dermal sinus.

Segmental spinal dysgenesis is a rare form of spinal dysraphism. We report a case of segmental hypoplasia of the spinal cord extending from T6 to L1 vertebral levels, with a dorsal dermal sinus, diagnosed by spinal sonography and MRI and confirmed at surgery. The probable pathogenesis is suggested.

Diagnosis, Differential↗