Biomedical subjects

Bakhtiar Yamini

Publications and source records attributed to Bakhtiar Yamini.

11 recordsLinked to original sources

PubMed2007

Correction of sagittal craniosynostosis using a novel parietal bone fixation technique: results over a 10-year period.

Isolated sagittal synostosis is a common form of craniosynostosis affecting roughly 1 in 5,000 children at birth. This results in a scaphocephalic head shape with a characteristically elongated anterior-posterior dimension and narrowed biparietal diameter. We present our experience with the correction of scaphocephaly due to sagittal synostosis using cranial vault reconstruction with a novel form of parietal bone fixation in 21 patients over 10 years. The medial fixation results in a hinging effect whereby transverse brain growth at the squamoid suture is enhanced. This results in excellent cosmetic results that are immediate and durable without the need for postoperative molding helmets. Furthermore, the complications associated with this procedure are limited.

Bone Wires↗

PubMed2006

Intradural spinal Wilm's tumor metastasis: case report.

OBJECTIVE: Wilm's tumor metastasis to the central nervous system (especially the spine) is rare. We present a case of a lumbosacral intradural drop metastasis in a male child with a remote history of intracerebral Wilm's tumor metastases. CLINICAL PRESENTATION: A 7-year-old boy with known metastatic Wilm's tumor was discovered to have left frontal and parietal metastases. He subsequently underwent craniotomy and gross total resections of those lesions. Four years later, he developed low back pain and lower extremity weakness and was found to have an intradural lumbosacral lesion without intracranial recurrence. INTERVENTION: The patient underwent lumbar laminectomy for resection of the intradural lesion. The tumor was found to be in the subarachnoid space and displaced the nerve roots of the cauda equina to the periphery of the thecal sac. The nerve roots were matted and encased within tumor tissue, thereby limiting the surgery to biopsy only. Postoperatively, the patient received radiation to the lesion. Unfortunately, follow-up imaging 4 months later revealed little tumor regression, and the patient's neurological condition did not improve significantly. CONCLUSION: Spinal intradural Wilm's tumor metastases are rare. This is the only reported case in the literature of a probable drop metastasis from an intracerebral source. Although the optimal treatment for intra- or extradural Wilm's tumor spine metastases is not known, our patient did not make significant neurological improvement with radiation therapy.

Brain Neoplasms↗

PubMed2006

Craniopharyngiomas: an update.

Craniopharyngiomas have been challenging practitioners for over 100 years. These benign cystic tumors are thought to be a part of a continuum of ectodermal cystic lesions found in the suprasellar region. They are rare tumors found in both the adult and pediatric populations. Patients most often present with findings associated with ventricular outflow obstruction causing hydrocephalus, optic chiasm compression resulting in visual dysfunction or hypothalamic/pituitary compression leading to endocrinopathy. The mainstay of treatment involves a combination of radical or limited surgery followed by radiotherapy. Other adjunctive strategies include cyst fenestration, Ommaya catheter implantation and brachytherapy. Patients in general have high long-term survival but can have significant tumor- and treatment-associated morbidity requiring a lifetime of medical and psychological management.

Craniopharyngioma↗

PubMed2005

Chemo-inducible gene therapy.

Chemo-inducible cancer gene therapy is a potential new treatment for solid tumors that may in part enhance the anti-tumor effects of chemotherapy while minimizing toxicity. This approach combines viral vectors expressing cytotoxic transgenes that can be transcriptionally activated by DNA-damaging agents. The development of chemo-inducible gene therapy has numerous implications for the treatment of both localized and metastatic disease in patients with solid tumors.

Antineoplastic Agents↗

PubMed2005

Surgery for low-grade gliomas: current evidence and controversies.

Despite decades of studies, the surgical management of cerebral low-grade gliomas remains quite controversial. Recommendations range from observation with biopsy to radical resection. This controversy arises from several factors, chief of which is the lack of prospective, randomized studies specifically addressing the issue of resection. Nevertheless, the available data, with its inherent inadequacies, must be used to help guide the care of these patients. This article reviews the current literature on the role of surgery for these tumors and attempts to put forward reasonable treatment options in an area where even the American Association of Neurological Surgeons can find no standard management to recommend aside from biopsy prior to the onset of therapy.

Brain Neoplasms↗

PubMed2004

Transcriptional targeting of adenovirally delivered tumor necrosis factor alpha by temozolomide in experimental glioblastoma.

Temozolomide is an oral alkylating agent shown to have modest efficacy in the treatment of glioblastoma multiforme. Tumor necrosis factor alpha (TNF-alpha) is a polypeptide cytokine with synergistic antitumor activity in combination therapy with alkylating agents. We investigated the combined use of Ad.Egr-TNF, a replication-defective adenoviral vector encoding the cDNA for TNF-alpha under the control of chemo-inducible elements of the egr1 gene promoter, and intraperitoneal temozolomide in an intracranial human malignant glioma model. In hind limb U87MG xenografts, temozolomide produced a 6.4-fold greater induction of TNF-alpha after infection with Ad.Egr-TNF compared with Ad.Egr-TNF alone at 96 hours (P < 0.02). TNF-alpha and temozolomide combination leads to a synergistic decrease in U87 cell viability at 72 hours compared with either treatment alone (P < 0.001). Median survival for animals treated with Ad.Egr-TNF alone, temozolomide alone, and Ad.Egr-TNF/temozolomide was 21, 28, and 74 days, respectively (P < 0.001 by log-rank). Flow cytometric assessment of apoptosis revealed a synergistic increase in U87 cell apoptosis in vitro at 72 hours (P < 0.05), and terminal deoxynucleotidyl transferase-mediated dUTP-biotin nick end-labeling (TUNEL) evaluation of tumor sections revealed significantly increased TUNEL-positive cells after combination treatment compared with either treatment alone (P < 0.05). In conclusion, combination treatment with transcriptionally activated intratumoral TNF-alpha and systemic temozolomide significantly prolongs survival in an experimental glioblastoma multiforme model.

Adenoviruses, Human↗

PubMed2004

Pseudotumor cerebri patients with shunts from the cisterna magna: clinical course and telemetric intracranial pressure data.

OBJECTIVE: Shunting of cerebrospinal fluid (CSF) to an extracranial site is the mainstay of treatment of absorptive hydrocephalus and pseudotumor cerebri. On occasion, both lateral ventricles and the lumbar space become unsuitable for placement of a functioning CSF drainage catheter. We have encountered several such patients and describe our strategy of shunting from the cisterna magna to the pleural space or cardiac atrium. METHODS: We report a retrospective review of the clinical course of five patients with cisternal shunts and intracranial pressure telemonitoring devices. RESULTS: Cisternal shunting was able to successfully drain CSF to a normal pressure in all five patients. CSF pressure data collected from those patients indicate that the CSF pressure dynamics in cisternal shunts is similar to that of ventricular shunts. However, the cisternal shunting and subsequent high revision rate did result in a significant number of complications and two shunt infections. CONCLUSION: Shunting CSF from the cisterna magna in the absence of another suitable drainage site does result in acceptable reduction of elevated intracranial pressure. However, the technique is associated with a high complication rate that may reflect the population of patients in whom this technique is required.

Adult↗

PubMed2004

Initial endoscopic management of pineal region tumors and associated hydrocephalus: clinical series and literature review.

OBJECT: The authors report their experience in six patients with pineal tumors and associated hydrocephalus who underwent an endoscopic biopsy procedure and third ventriculocisternostomy (ETVC) in a single sitting. METHODS: The ETVC was successfully performed without complication in all patients; however, a ventriculoperitoneal shunt was eventually required in four. Histological diagnosis was successfully established in four patients. The authors also reviewed the literature to assess reports involving ETVC and tumor biopsy sampling in patients with pineal tumors and hydrocephalus. A total of 54 cases, including those in this study, have been reported. Fifteen percent of the patients eventually required placement of a ventricular shunt. The transient complication rate was 15% with no death. A positive tissue diagnosis was established in 89% of the cases overall. CONCLUSIONS: The authors conclude that the endoscopic management of patients with pineal region masses and hydrocephalus may be a preferred initial strategy.

Adolescent↗

PubMed2002

Nitric oxide inactivation in brain by a novel O2-dependent mechanism resulting in the formation of nitrate ions.

In order for nitric oxide (NO) to function as a biological messenger it has to be inactivated, but little is known of how this is achieved. In cells from the brain, we have recently shown the existence of a powerful NO sink that 'shapes' NO signals for targeting its receptor, soluble guanylate cyclase, whilst simultaneously preventing NO rising to toxic concentrations [Griffiths and Garthwaite (2001) J. Physiol. (Cambridge, U.K.) 536, 855-862]. In the present study, the properties of this sink were investigated further. Inactivation of NO was preserved in rat brain homogenates. In both cerebellar cell suspensions and brain homogenates, NO inactivation required O(2) and, from measurements in homogenates, the principal end-product was NO(-)(3), which is also the main product of endogenously formed NO in vivo. Direct chemical reaction with O(2), superoxide anions or haemoglobin was not responsible. Consumption of NO was, however, inhibited by heat or protease treatment. Pharmacological tests were negative for several candidate enzymes, namely cytochrome c oxidase, H(2)O(2)-dependent haem peroxidases, prostaglandin H synthase, 12/15-lipoxygenase and a flavohaemoglobin-like NO dioxygenase. The capacity of the NO sink in cells was limited because regeneration of the activity was slow (2 h). It is concluded that NO is consumed in the brain through a novel protein, ultimately forming NO(-)(3), and that the slow regeneration of the activity provides a scenario for NO to become toxic.

5,8,11,14-Eicosatetraynoic Acid↗

PubMed2002

Lumboperitoneal shunting as a treatment for slit ventricle syndrome.

OBJECTIVE: Slit ventricle syndrome (SVS) has been described in hydrocephalus patients who continue to have shunt malfunction-like symptoms in the presence of a functioning shunt system and small ventricles on imaging studies. These symptoms usually present years after shunt placement or revision and can consist of headache, nausea and vomiting, lethargy and decreased cognitive skills. Treatments offered range from observation, medical therapy (migraine treatment) and shunt revision to subtemporal decompression or cranial vault expansion. We describe a subset of patients with SVS who were symptomatic with high intracranial pressure (ICP) as measured by sedated lumbar puncture and whose symptoms completely resolved after lumboperitoneal shunt (LPS) placement. METHODS: Seven patients with a diagnosis of SVS underwent lumboperitoneal shunting. The age at shunting ranged from 3 to 18 years. Most had undergone recent ventriculoperitoneal shunt (VPS) revisions for presentation of shunt malfunction-like symptoms. Despite this, all remained symptomatic and underwent a sedated lumbar puncture to measure opening pressure (OP). All had high OP in spite of a functional VPS and underwent LPS placement. RESULTS: All 7 patients had a prolonged period of overdrainage symptoms after lumboperitoneal shunting that resolved completely over several weeks. The initial etiology of hydrocephalus was reported to include trauma, aqueductal stenosis and intraventricular hemorrhage of prematurity. Two patients required revision of their LPS, after which their symptoms again resolved. CONCLUSION: In a certain subset of patients with SVS who are symptomatic from increased ICP, placement of an LPS is an effective treatment option. It appears that this subgroup of patients previously treated with ventriculoperitoneal shunting behave in a fashion similar to pseudotumor cerebri patients and respond well to lumboperitoneal shunting.

Adolescent↗

PubMedDate not supplied

Endoscopic cyst fenestration outcomes in children one year of age or less.

The use of endoscopic fenestration (EF) is becoming an increasingly common treatment for symptomatic intracranial cysts. Very little data exist regarding outcomes for this procedure in children 1 year of age or younger. We retrospectively reviewed the clinical outcomes of 8 children 1 year of age or less treated at our institution with endoscopic cyst fenestration. The mean follow-up was roughly 2.5 years. These data were combined with 17 other cases obtained from the published literature. EF was successful in rendering patients shunt-free or minimizing the number of ventricular catheters in 18 of 26 operations. There were 8 outright failures -- two in 1 patient. Given the risks and complications of cerebrospinal fluid shunting in children less than 1 year of age, we advocate the consideration of EF as initial treatment of symptomatic intracranial cysts.

Brain↗