Antineoplastic activity of plant-derived compounds mediated through inhibition of histone deacetylase: a review.

In the combat of treating cancer recent therapeutic approaches are focused towards enzymatic targets as they occupy a pivotal participation in the cascade of oncogenesis and malignancy. There are several enzymes that modulate the epigenetic pathways and chromatin structure related to cancer mutation. Among several epigenetic mechanisms such as methylation, phosphorylation, and sumoylation, acetylation status of histones is crucial and is governed by counteracting enzymes like histone acetyl transferase (HAT) and histone deacetylases (HDAC) which have contradictory effects on the histone acetylation. HDAC inhibition induces chromatin relaxation which forms euchromatin and thereby initiates the expression of certain transcription factors attributed with apoptosis, which are mostly correlated with the expression of the p21 gene and acetylation of H3 and H4 histones. Most of the synthetic and natural HDAC inhibitors elicit antineoplastic effect through activation of various apoptotic pathways and promoting cell cycle arrest at various phases. Due to their promising chemo preventive action and low cytotoxicity against normal host cells, bioactive substances like flavonoids, alkaloids, and polyphenolic compounds from plants have recently gained importance. Even though all bioactive compounds mentioned have an HDAC inhibitory action, some of them have a direct effect and others enhance the effects of the standard well known HDAC inhibitors. In this review, the action of plant derived compounds against histone deacetylases in a variety of in vitro cancer cell lines and in vivo animal models are articulated.

Dengue encephalitis with predominant cerebellar involvement: report of eight cases with MR and CT imaging features.

OBJECTIVES: CNS dengue infection is a rare condition and the pattern of brain involvement has not been well described. We report the MR imaging (MRI) features in eight cases of dengue encephalitis. MATERIALS AND METHODS: We retrospectively searched cases of dengue encephalitis in which imaging was performed. Eight cases (three men, five women; age range: 8-42 years) diagnosed with dengue encephalitis were included in the study. MR studies were performed on 3-T and 1.5-T MR clinical systems. Two neuroradiologists retrospectively reviewed the MR images and analysed the type of lesions, as well as their distribution and imaging features. RESULTS: All eight cases exhibited MRI abnormalities and the cerebellum was involved in all cases. In addition, MRI signal changes were also noted in the brainstem, thalamus, basal ganglia, internal capsule, insula, mesial temporal lobe, and cortical and cerebral white matter. Areas of susceptibility, diffusion restriction, and patchy post-contrast enhancement were the salient imaging features in our cohort of cases. CONCLUSION: A pattern of symmetrical cerebellar involvement and presence of microbleeds/haemorrhage may serve as a useful imaging marker and may help in the diagnosis of dengue encephalitis.

Demonstration of different histological layers of the pachygyria/agyria cortex using diffusion tensor MR imaging.

PURPOSE: Pachygyria/agyria are congenital brain malformations characterized by presence of a few broad, flat gyri with thickened cortex, resulting from arrest of neuronal migration in early gestation. We are hereby describing diffusion tensor imaging findings in different histological layers of lissencephaly cortex in two children. METHOD: DTI in addition to conventional MR imaging was performed in two children on a 3 T MRI and post-processed with vendor supplied software to generate the fractional anisotropy, mean diffusivity and trace maps. Tractography was also performed to identify presence of tracts in the thickened cortex. RESULTS: DTI demonstrated the dysplastic multilayered cortex in cases of pachygyria/agyria; the thickened fourth layer and superficial layer demonstrated high anisotropy on diffusion tensor imaging. CONCLUSION: DTI is a useful tool for identifying gross histological features of pachygyria-agyria complex. Superficial layer and thickened fourth layer demonstrate high anisotropy. Identification of anisotropy in the superficial layer has not been described in previous reports.

Tree-in-bud Appearance in the Brain: Fungal Granuloma on Contrast Magnetic Resonance Imaging.

We describe a case of dural-based homogenously enhancing fungal granuloma in a 29-year-old male who presented with 3 months history of headache. The peculiarity of the case was that there were streaky areas of enhancement around the lesion in the brain parenchyma which resembled tree-in-bud like appearance. The patient underwent surgery and histopathological analysis revealed numerous Aspergillus hyphae. To the best of our knowledge, this is the first case report of a fungal granuloma with atypical parenchymal enhancement pattern.

Infantile holocord cellular ependymoma with communicating hydrocephalus: unusual presentation of a rare case.

We present a case of infantile holocord ependymoma in a 4-month-old boy who presented with infection of ventriculoperitoneal shunt done elsewhere for a communicating hydrocephalus. On magnetic resonance imaging, a diffuse holocord T2-hyperintense, T1-hypointense intramedullary bulky lesion with syringomyelia in the cervical level was seen. To the best of our knowledge, this is the first case of infantile holocord ependymoma. As the extent of morbidity associated with a spinal cord tumor is high, an increased level of suspicion and the need for a complete spinal cord screening in a case of infantile hydrocephalus without obvious clinical and radiological evidence of intracranial abnormality is emphasized.

Unusual imaging findings in brain and spinal cord in two siblings with maple syrup urine disease.

Maple syrup urine disease (MSUD) is a rare metabolic disease affecting the neural tissue. While the brain abnormalities present on MRI are well known, spinal imaging features have not been studied. We herewith report an unusual finding of enlarged Virchow Robin spaces in brain and novel spinal cord changes in two biochemically diagnosed cases of MSUD. To the best of our knowledge, spinal MRI findings in cases of MSUD have not been previously reported. Knowledge of spinal MRI findings may be useful in diagnosis of this rare disorder.

Role of multidetector computed tomography in evaluating complications following endovascular repair of aortic aneurysm.

OBJECTIVE: To study the role of multidetector computed tomography (MDCT) in evaluating various complications following endovascular stenting of aortic aneurysms. MATERIALS AND METHODS: Over a period of 2 years (June 2005 to June 2007), 50 patients with aortic aneurysm on computed tomography (CT) angiogram were prospectively studied. Images were acquired on a 64 slice multidetector row CT scanner (GE-LightSpeed VCT) after intravenous administration of nonionic iodinated contrast. Nineteen patients underwent endovascular stent-graft repair based on their medical and surgical risk factors. Stent-graft related complications were recorded by CT angiography and analyzed using descriptive statistics. RESULTS: Most common complication related to the endovascular stent-graft placement was endoleak (44.4%), followed by puncture site hematoma (27.8%), thrombotic occlusion of a limb of the bifurcated stent graft, kinking of the stent-graft, and difficult catheterization with intimal tear in the common iliac artery were 5.6% each. Poststent diameter of the aneurysm was an important predictor of endoleaks. All the patients with either increase or no change in the aneurysm size had endoleaks. CONCLUSION: MDCT angiography is an important modality in identifying, describing, and following up the various complications following endovascular repair of aortic aneurysms, endoleaks being the most common complication. Decrease in the poststent diameter of the aneurysm suggested a good outcome.

Double aortic arches, esophageal atresia and tracheal compression.

We report a case of double aortic arch in a 12-month-old male infant well delineated on 64 slice computed tomography scan. It formed a complete vascular ring around the trachea compressing it. The symptoms resolved after surgical division of the ring.