Biomedical subjects

A M Rojiani

Publications and source records attributed to A M Rojiani.

33 records · Page 2Linked to original sources

PubMed1995

Delayed occurrence of cerebellar pleomorphic xanthoastrocytoma after supratentorial pleomorphic xanthoastrocytoma removal. Case report.

The authors report the case of a 36-year-old woman who underwent gross total resection of a right cerebellar pleomorphic xanthoastrocytoma with atypical features. She had undergone surgery 16 years previously for what was thought to be a right frontal glioblastoma multiforme. In retrospect, based on the histopathology and the clinical course, both lesions were considered to represent atypical variants of pleomorphic xanthoastrocytoma. This report examines the histological and clinical characteristics of this posterior fossa lesion, which exhibited histologically malignant features but has run a relatively indolent course.

Adult↗

PubMed1994

Electrolyte-induced demyelination in rats. 1. Role of the blood-brain barrier and edema.

The blood-brain barrier (BBB) was studied in rats with electrolyte-induced demyelination (EID), an experimental model for central pontine myelinolysis. Intravenously injected peroxidase was extravasated at 3 h post hypertonic saline injection (PHS) into regions frequently involved in EID. Increased pinocytotic activity and focal interendothelial gaps were seen at 3 h PHS and less frequently at 48 h PHS. Measurement of total cerebral water content revealed an increase during the hyponatremic phase. This was followed by a marked increase at 3 h PHS with continued increment at 48 h PHS. Intracellular edema with accumulation of fluid within neurites and astrocytic processes was noted during the hyponatremic phase, whereas extracellular edema developed after hypertonic saline injection. The implications of disrupted BBB and its role in the pathogenesis of EID are discussed.

Animals↗

PubMed1994

Electrolyte-induced demyelination in rats. 2. Ultrastructural evolution.

This study presents the electron microscopic evolution of lesions in electrolyte-induced demyelination (EID) in rats, a lesion which bears striking histological and clinical similarity to central pontine myelinolysis. The earliest change was observed during the hyponatremic phase and consisted of minimal intracellular edema present throughout the brain. Following the injection of hypertonic saline, additional changes were observed which were restricted to sites previously reported to be frequently involved in EID. Early dilatation of the inner tongue of oligodendrocyte cytoplasm in myelinated nerve fibers was observed at 3 h post hypertonic saline injection (PHS). This was followed, at 48 h PHS, by the appearance of degenerative changes consistent with dying oligodendrocytes. Well-delineated, vacuolar and spongy lesions, seen by light microscopy, were present by 48 h PHS at the same sites as above. Electron microscopically, this appearance was found to be due to striking intramyelinic edema. By 96 h PHS, macrophages containing myelin and other cellular debris were frequently present at these sites. Concomitantly, myelin sheaths underwent vesicular disruption and disintegration. This sequence of events suggests a lesion of the oligodendrocyte-myelin complex, secondary to initial blood-brain barrier damage and edema.

Animals↗

PubMed1994

Early-onset respiratory failure caused by severe congenital neuromuscular disease.

Two unrelated infants with low Apgar scores, pneumothoraces, and severe pulmonary hypertension were treated with extracorporeal membrane oxygenation while receiving chemical sedation and neuromuscular paralysis. After decannulation from extracorporeal membrane oxygenation, hypotonia and hypoventilation persisted. Neurologic evaluation confirmed that both infants had a congenital myopathy.

Extracorporeal Membrane Oxygenation↗

PubMed1991

Hepatic hemangioblastoma. An unusual presentation in a patient with von Hippel-Lindau disease.

We report a case of multiple capillary hemangioblastomas of the liver occurring in a patient with von Hippel-Lindau disease and a history of previous cerebellar and spinal hemangioblastomas. Although rare examples of this tumor have previously been recorded in the pancreas, kidney, and urinary bladder, this appears to be the first recorded case with hepatic involvement. The histology and immunohistochemical appearance of this neoplasm are identical with those of the cerebellar tumor. We believe it represents a separate primary neoplasm rather than metastatic disease.

Adult↗

PubMed1987

Protective effect of steroids in electrolyte-induced demyelination.

Electrolyte-induced demyelination (EID), an experimental model for central pontine myelinolysis was produced in rats by inducing hyponatremia followed by hypernatremia. There was a marked reduction in the number and size of lesions developing in animals that were bled repeatedly by tail transection during induction of the disease. Subsequently a similar protective effect was produced in animals by injecting a single dose of dexamethasone, one hour before the induction of hypernatremia. These findings suggest that steroids may be useful in preventing central pontine myelinolysis from developing in high risk patients requiring urgent correction of hyponatremia.

Animals↗

PubMedDate not supplied

CT findings of retroperitoneal malignant mesenchymoma.

Malignant mesenchymoma (MM) is a rare mesenchymal neoplasm which, by definition, demonstrates at least two distinct types of malignant mesenchymal differentiation. We present the computed tomographic (CT) findings of a 42-year-old female with a pathologically proven retroperitoneal MM consisting of osteoid production combined with foci of liposarcoma and Kaposi sarcoma. MM should be considered along with extraosseous osteosarcoma and teratoma in the differential diagnosis for unusual large heterogeneous retroperitoneal masses with massive calcification.

Adult↗

PubMedDate not supplied

Immunohistochemical localization of erythropoietin and its receptor in the developing human brain.

We have previously shown erythropoietin (Epo) and its receptor (Epo-R) to be present in the fetal human central nervous system (CNS), and Epo to be present in the spinal fluid of normal preterm and term infants. To investigate the cellular specificities and developmental patterns of expression of these polypeptides in the human brain-areas that have not been well researched-we designed the following study. Human brains ranging in maturity from 5 weeks post-conception to adult were preserved at the time of elective abortion, surgical removal (tubal pregnancy, or removal for temporal lobe epilepsy), or autopsy. Immunohistochemistry was used to localize Epo and Epo-R reactivity in brains of different stages of development. Astrocytes, neurons, and microglia were identified in sequential tissue sections by specific antibodies. At 5 to 6 weeks post-conception, both Epo and Epo-R localized to cells in the periventricular germinal zone. At 10 weeks post-conception, Epo immunoreactivity was present throughout the cortical wall, with the most intense immunoreactivity present in the ventricular and subventricular zones. Epo-R, in contrast, was localized primarily to the subventricular zone, with little staining evident in the ventricular zone. In late fetal brains, Epo-R reactivity was most prominent in astrocytic cells, although modest reactivity was observed in certain neuron populations. In contrast, Epo staining localized primarily to neurons in fetal brains, although a subpopulation of astrocytes was also immunoreactive. In postnatal brains, both astrocyte and neuron populations were immunoreactive with antibodies to Epo-R and Epo. From these results it is clear that Epo and its receptor are present in the developing human brain as early as 5 weeks post-conception, and each protein shows a specific distribution that changes with development. We speculate that Epo is important in neurodevelopment, and that it also plays a role in brain homeostasis later in life, functioning in an autocrine or paracrine manner.

Adult↗

PubMedDate not supplied

Ruptured intracranial aneurysm presenting as cerebral infarction in a young child.

We describe a 15-month-old girl who presented with an acute hemiplegia. The sequence of events appears to have been clinically silent subarachnoid hemorrhage, vasospasm, infarction and a second lethal hemorrhage 3 months later. The old infarction was seen on computed tomography during her second illness. Autopsy confirmed the presence of a recent rupture of an intracranial aneurysm and old hemorrhage. In addition there was an unusual fibroblastic proliferation in the aneurysm wall. This case demonstrates that clinically silent subarachnoid hemorrhage, vasospasm and infarction can occur as complications of aneurysms, even in very young children.

Brain↗

PubMedDate not supplied

Congenital CNS primitive neuroectodermal tumor: case report and review of the literature.

A 30-week gestational age male fetus was found to have a congenital neoplasm involving the posterior cranial fossa, identified by fetal ultrasound examination in utero. Histological and immunohistochemical examination confirmed a diagnosis of primitive neuroectodermal tumor (PNET) of the posterior fossa, also referred to as medulloblastoma. Although PNETs have been well documented, there are relatively few reports of these occurring as congenital neoplasms. We present a case of an in utero, congenital PNET with a review of the literature and discussion of the criteria defining congenital tumors.

Adolescent↗

PubMedDate not supplied

CD44 expression and MMP-2 secretion by mouse glioma cells: effect of interferon and anti-CD44 antibody.

We have previously reported that invasiveness of mouse glioma G-26, which expresses CD44 adhesion molecule, was inhibited in vitro following treatment with anti-CD44 antibody or mouse interferon alpha/beta (MuIFN alpha/beta). Here, we evaluated whether the expression of transmembrane CD44 adhesion molecule and/or secretion of extracellular matrix metalloproteinases (MMPs) were affected when glioma cell invasion was inhibited. Flow cytometric evaluation of CD44 adhesion molecule expression in G-26 glioma using anti-CD44 antibody, confirmed that G-26 cells were CD44+. Following 3-day treatment with MuIFN alpha/beta at 8 x 10(2) or 8 x 10(3) IU/ml of glioma cells, the expression of CD44 was not significantly affected as reflected by CD44+ cell number and fluorescence intensity. The pretreatment of glioma cells for 1 day with anti-CD44 antibody resulted in a 30-60% decrease of CD44 expression. This coincided with significantly (p < 0.05) lower cell activity as judged by MTT assay for mitochondrial activity. The zymographic evaluation of MMP activity in the G-26 glioma cell culture showed a high level of the active form of MMP-2. This level of MMP-2 was decreased following 3 day treatment of G-26 glioma cells with either 8 x 10(2) or 8 x 10(3) IU/ml of MuIFN alpha/beta but only the latter concentration produced statistically significant 55% decrease. However, following a 1 day treatment of G-26 glioma cells with anti-CD44 antibody, the level of active MMP-2 form was not significantly affected. These findings indicate that while the inhibitory effect of IFN on glioma invasion was accompanied by a decreased level of the active form of MMP-2 released extracellularly, the expression of the transmembrane CD44 adhesion molecule was not affected. Conversely, anti-CD44 antibody pretreatment of G-26 glioma, which led to the inhibition of glioma invasion, resulted in decreased CD44 expression and lower cell activity but had no effect on the MMP-2.

Animals↗

PubMedDate not supplied

Extensive replacement of spinal cord and brainstem by hemangioblastoma in a case of von Hippel-Lindau disease.

We report an extremely unusual case of von Hippel-Lindau disease, characterized by almost total replacement of the spinal cord and most of the medulla by capillary hemangioblastoma (CHB). A 34-year-old female presented 20 years earlier with signs of lower limb weakness. She developed progressive quadriplegia despite multiple surgical attempts to remove separate CHBs from the midthoracic and cervical spinal cord. Spinal cord lesions continued to develop as did multiple cerebellar CHBs. She eventually became respirator-dependent and died following severe upper gastrointestinal hemorrhage. At autopsy there was extensive replacement of spinal cord and medulla by CHB as well as multiple solid and cystic cerebellar tumors. Both kidneys were enlarged and largely replaced by renal cell carcinomas and simple cysts. Additionally she had small pancreatic cysts and microscopic pulmonary hamartomas were observed. There was no evidence of retinal lesions clinically or at autopsy. Light microscopic and immunohistochemical studies of the lesions are presented. The early onset of this disease in a female, with such extensive spinal cord involvement, in addition to other CNS and visceral manifestations of von Hippel-Lindau disease, is unusual and has not been previously reported.

Adult↗

PubMedDate not supplied

Extradural myxopapillary ependymoma: report of two cases and review of the literature.

The cauda equina is the most frequent location for ependymomas, particularly the myxopapillary variant, which generally arises from the filum terminale. These tumors have a characteristic histopathologic pattern and are usually easily recognized. The occurrence of these tumors in an extradural, sacrococcygeal, or subcutaneous location may prove challenging, particularly in the absence of any obvious central nervous system connection. We describe two such extradural cases, one with multiple regional and distant metastases and the other with multiple recurrences. The origin of these tumors from subcutaneous sacrococcygeal ependymal rests is postulated on the basis of earlier reports. Clinical and histopathological features are described and a review of the literature is presented.

Adult↗

PubMedDate not supplied

Primary intracranial germ cell tumors: clinicopathologic review of 32 cases.

Primary intracranial germ cell neoplasms are rare tumors and constitute a heterogeneous group. We have reviewed 32 cases, over a 21-year period, from the University of Florida. The cases include 22 germinomas, 6 mixed germ cell tumors, and 4 teratomas. The clinical presentations in these cases were more closely related to the location of the tumor, that is, pineal or suprasellar, rather than the histologic subtype. Neuroimaging evaluation was useful in distinguishing between germinomas, teratomas, and other mixed germ cell tumors (MGCTs), primarily by evaluation of cystic versus solid lesions (teratoma versus germinoma), contents of cysts (teratoma versus MGCT), and infiltrative nature of the tumors (MGCT), although cytologic-histopathologic confirmation remains necessary. Germinomas responded favorably to radiation therapy with survival periods of over 16 years; MGCTs were treated with combination chemotherapy and radiation, with a markedly poorer prognosis. This study underlines the critical significance of histopathologic evaluation of the tumor in determining therapeutic interventions as well as prognosis.

Adolescent↗

PubMedDate not supplied

Retrorectal cyst-hamartomas and sacral dysplasia: MR appearance.

Retrorectal cyst-hamartoma, an uncommon lesion, arises from hindgut embryonic remnants and may be associated with sacral anomalies. Such a lesion is presacral, multicystic, and lined with glandular or transitional epithelium. Malignant transformation of these lesions has been reported. We describe the clinical, pathologic, and imaging findings in an infant.

Cysts↗