Biomedical subjects

N S Radhakrishnan

Publications and source records attributed to N S Radhakrishnan.

8 recordsLinked to original sources

PubMed1998

Mitochondrial myopathies--a clinicopathological study.

Mitochondrial myopathies are heterogeneous group of clinical disorders that can affect multiple systems besides skeletal muscles. The mitochondrial abnormalities in the skeletal muscles are morphologically identified by the presence of characteristic Ragged-red fibers (RRF) in the cryostat sections of the muscle stained with modified Gomori's trichrome stain. In this retrospective study, clinical and histopathological features in six patients with mitochondrial myopathies have been analysed. The utility of histochemical methods in confirming the diagnosis of mitochondrial myopathy has been emphasised.

Adolescent↗

PubMed1995

Nucleolar organizer regions in pituitary adenomas.

In this study, thirty-two non-functional and eighteen functional pituitary adenomas were analysed for the presence of argyrophilic nucleolar organizer regions (Ag-NORs) in paraffin sections, using an one-step silver-colloidal staining method. Differences in the mean Ag-NOR numbers of functional pituitary adenomas were statistically significant than those of non-functional pituitary adenomas. It is being emphasised that evaluation of Ag-NOR count is a more reliable index than the presence of mitotic figures in predicting the proliferative activity as well as possibility of recurrence in a patient with pituitary adenoma.

Adenoma↗

PubMed1994

Utility of silver-colloidal staining method in the diagnosis of medulloblastoma.

Histopathological features of medulloblastomas are usually distinctive. However in rare instances, a distinction between the neoplastic cells of medulloblastoma and the neurones in the cerebellar internal granular layer becomes difficult at light microscopic level. In order to distinguish presence of argyrophilic Nucleolar Organizer Regions (Ag-NORs) was analysed in the paraffin sections of medulloblastoma as well as in the cerebellar internal granular layer. The neoplastic cells in medulloblastoma contained a mean 4.78 Ag-NOR per nucleus while the neurones in cerebellar internal granular layer contained a mean Ag-NOR 0.90 +/- 0.12 per nucleus. Compound Ag-NORs were present in the cells of medulloblastoma while they were absent in the neurones of cerebellar internal granular layer. The results of this study indicate that Ag-NOR technique may be useful in an uncommon situation, where a histopathological distinction between cells of medulloblastoma and neurones in the cerebellar internal granular layer becomes difficult.

Cerebellar Cortex↗

PubMed1993

Nucleolar organizer regions in meningiomas.

Paraffin sections of 305 meningeal tumours were analysed for the presence of nucleolar organizer region (Ag-NOR) in the neoplastic cells, using a one step silver-colloidal staining method. The mean (+/- SEM) Ag-NOR counts were 2.73 +/- 0.21 for atypical and 2.91 +/- 0.18 for papillary variants of meningioma. In meningotheliomatous and transitional variants of meningioma, the mean Ag-NOR counts were 1.41 +/- 0.34 and 1.38 +/- 0.31, respectively. The recurrence rates were significantly higher in atypical meningiomas than in other histopathological variants (p < 0.05). Differences in the mean Ag-NOR numbers between meningothelial and transitional variants in their primary and recurrent tumours were not significantly different (p > 0.05). The results of this study indicates that estimation of Ag-NORs can be applied in predicting the aggressive clinical behaviour of primary meningeal tumours.

Brain↗

PubMed1993

Application of silver colloidal staining method in the diagnosis of intracranial glioma.

A silver colloidal staining technique for the demonstration of argyrophilic nucleolar organizer regions (Ag-NORs) was used on the paraffin sections of reactive gliosis and grade I astrocytoma tissue. Quantitative as well as qualitative differences of Ag-NORs were found between the cells of reactive gliosis and grade I astrocytoma. In cases of reactive gliosis, the Ag-NOR counts averaged 1.19 +/- 0.16 per nucleus, while in grade I astrocytoma, Ag-NOR counts averaged 2.36 +/- 0.32 per nucleus (P < 0.05). Compound Ag-NORs were also seen in the nuclei of cells in grade I astrocytoma while they were not present in the nuclei of cells in cases of reactive gliosis. The results of the study indicate that Ag-NOR technique is an useful method and can be applied in situations where a distinction between grade I astrocytoma and reactive gliosis becomes difficult at the light microscopic level.

Astrocytoma↗

PubMed1993

Diagnostic utility of immunohistochemical techniques in intramedullary Schwann-cell tumours.

Histopathologic features in two intramedullary schwann-cell tumours, closely resembled with those of fibrillary astrocytoma and could not be differentiated from each other by the conventional histochemical stains. However application of tumour markers-Glial fibrillary acidic protein (GFAP) and S-100 protein were found to be useful in differentiating these two tumours and thus helped in making an accurate histopathological diagnosis in these two patients.

Astrocytoma↗

PubMed1991

Immunohistochemical demonstration of mycobacterial antigens in intracranial tuberculoma.

Mycobacterial antigens have been demonstrated immunohistochemically in the paraffin sections of 10 intracranial tuberculous granulomas and the results were compared with the detection of acid fast bacilli by conventional Ziehl-Neelsen method. In none of the 10 specimens, acid fast bacilli were demonstrated while mycobacterial antigens were characterised as diffusely staining granular brownish-pink material within the cytoplasm of giant cells and macrophages. In 14 specimens of granulomatous lesions due to non-tuberculous aetiology, immunohistochemical stains were negative for mycobacterial antigen. Thus demonstration of mycobacterial antigen will be not only useful in establishing mycobacterial aetiology of a caseating intracranial granuloma but also can be used as an alternative method to the conventional Ziehl-Neelsen method.

Antigens, Bacterial↗

PubMedDate not supplied

Diagnostic utility of polymerase chain reaction and immunohistochemical techniques for the laboratory diagnosis of intracranial tuberculoma.

In an attempt to establish a tuberculous etiology, polymerase chain reaction (PCR) and immunohistochemical (IHC) methods were undertaken in formalin-fixed paraffin sections of ten surgical specimens of intracranial tuberculoma. The control group included an equal number of intracranial fungal granuloma. Both PCR and IHC methods did not yield false-positive results in fungal granuloma. PCR was found to be less sensitive (60%) than IHC method (80%) in this study. IHC method definitely possesses several operational advantages over PCR and is more suited to laboratories in developing countries for establishing a tuberculous etiology particularly in those patients in whom the conventional bacteriological methods did not confirm the diagnosis of tuberculoma.

Adolescent↗