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Biomedical subjects

N K Mishra

Publications and source records attributed to N K Mishra.

At least 37 records · Page 2Linked to original sources
PubMed1997

Idiopathic hypertrophic pachymeningitis: spectrum of the disease.

Hypertrophic pachymeningitis is extremely rare. It is a fibrosing inflammatory process which involves the dura mater, including the tentorium. Numerous pathological entities produce thickening of the pachymeninges, so that idiopathic hypertrophic pachymeningitis is a diagnosis of exclusion. We describe four patients with idiopathic hypertrophic pachymeningitis who had varied clinical presentation. Imaging studies revealed diffuse thickening of the pachymeninges; in one patient there was extensive dural sinus thrombosis. Since no identifiable cause was found, the cases were labelled as idiopathic.

Adult↗
PubMed1997

Positional MRI: a technique for confirming the site of leakage in cerebrospinal fluid rhinorrhoea.

We report confirmation of the site of leakage in two patients with spontaneous cerebrospinal fluid (CSF) rhinorrhoea by demonstrating CSF leaking on MRI. Both patients had midline anterior cranial fossa floor (cribriform plate/fovea ethmoidalis) dural-bone defects with arachnoid herniation with or without brain herniation into the upper part of the nasal cavity on MRI, which was subsequently confirmed surgically. Corresponding to the history of postural induction or aggravation of the rhinorrhoea, the CSF leak was demonstrated by the appearance of or increase in the sinonasal fluid collection by imaging the patient in the position of maximum leakage following initial images in the supine position.

Cerebrospinal Fluid Rhinorrhea↗
PubMed1997

Intracerebral haematoma formation in herpes simplex encephalitis: a case report.

Acute viral encephalitides have a high mortality and morbidity in all age groups. Early institution of appropriate medical treatment can alter the prognosis dramatically. Imaging studies may be normal or may show a wide variety of subtle findings in the initial stages. Knowledge of the extremely varied clinical as well as radiological expression of the disease is essential to enable timely diagnosis. A case is presented here of histopathologically proven Herpes simplex encephalitis (HSE), wherein a large intracerebral haematoma was seen on imaging studies. Observation of the accompanying subtle findings and knowledge of the variability of expression of this disease helped in reaching the correct diagnosis.

Cerebral Hemorrhage↗
PubMed1997

MR imaging of tubercular spinal arachnoiditis.

OBJECTIVE: The purpose of our study was to examine the spectrum of abnormalities seen on MR imaging in patients with tubercular spinal arachnoiditis. MATERIALS AND METHODS: A retrospective analysis of MR findings in 22 cases of tubercular spinal arachnoiditis was carried out. The diagnosis had been established on the basis of clinical features, evidence of associated tubercular meningitis or of tubercular spondylitis, and CSF analysis. RESULTS: Nineteen (86%) patients had involvement of more than one spinal region, with the dorsal region being most commonly involved. CSF showed increased signal intensity on T1-weighted images in 17 (77%) patients, leading to complete loss of cord-CSF interface in seven patients and shaggy cord outline in 10 patients. As suggested by increased signal intensity on T2-weighted images, we saw cord involvement in 18 (82%) patients. Three of these patients had evidence of cord cavitation. Other findings seen on unenhanced images were CSF loculations in five patients, nodules in subarachnoid space in six patients, and clumping of cauda equina nerve roots in six patients. Contrast-enhanced studies were available in 20 patients. Meningeal enhancement was seen in 16 (80%) of 20 patients, and nerve root enhancement was seen in six (30%) patients. Cord enhancement was seen in four (20%) of 20 patients. Enhancement was observed along the surface of the cord in two of these patients, whereas the other two patients showed central enhancement. Associated findings were tubercular spondylitis in two patients, basal exudate in eight patients, and intracranial granulomas in five patients. CONCLUSION: MR imaging revealed several pathologic changes that occur in patients with tubercular spinal arachnoiditis and, hence, may play an important role in the diagnosis of this entity.

Adult↗
PubMed1997

Imaging appearance of pachymeningeal tuberculosis.

OBJECTIVE: The purpose of our study was to examine imaging findings in patients with pachymeningeal tuberculosis. Imaging studies of seven patients with pachymeningeal tuberculosis were retrospectively reviewed. The diagnosis had been established on the basis of histopathology in three patients and response to antitubercular treatment in four patients. CONCLUSION: Tuberculosis can lead to localized or diffuse involvement of the pachymeninges. Most of the focal lesions were seen as en plaque, homogeneous, uniformly enhancing, dural-based masses. The lesions appeared hyperdense on plain CT scans, isointense to brain parenchyma on T1-weighted MR images, and isointense to hypointense on T2-weighted MR images. One patient had diffuse sheet-like thickening of the pachymeninges in the right hemicranium, involving both the supratentorial and infratentorial compartments.

Adult↗
PubMed1997

Role of macrophage colony-stimulating factor in atherosclerosis: studies of osteopetrotic mice.

Previous in vitro and in vivo studies have suggested that macrophage colony-stimulating factor (M-CSF) plays a role in atherogenesis. To examine this hypothesis, we have studied atherogenesis in osteopetrotic (op/op) mice, which lack M-CSF due to a structural gene mutation. Atherogenesis was induced either by feeding the mice a high fat, high cholesterol diet or by crossing op mice with apolipoprotein E (apo E) knockout mice to generate mice lacking both M-CSF and apo E. In both the dietary and apo E knockout models, M-CSF deficiency resulted in significantly reduced atherogenesis. For example, in the apo E knockout model, homozygosity for the op mutation totally abolished aortic atherogenesis in male mice and reduced the size of the lesions approximately 97% in female mice. Mice heterozygous for the op mutation also exhibited a significant decrease in lesion size. Among apo E knockout mice, the frequency of atherosclerosis in aortic arch was 0/6 (op/op), 1/15 (op/+), and 12/16 (+/+). The effect of the M-CSF on atherosclerosis did not appear to be mediated by changes in plasma lipoproteins, as the op mice exhibited higher levels of atherogenic lipoprotein particles. The effects of the op mutation on atherogenesis may have resulted from decreased circulating monocytes, reduced tissue macrophages, or diminished arterial M-CSF.

Animals↗
PubMed1996

Cervical intramedullary lipoma with unusual MRI features: case report.

Intramedullary (subpial) lipomas not associated with spinal dysraphism are very unusual [1]. A confident preoperative diagnosis is usually possible with MRI. We present a case of an isolated cervical intramedullary lipoma with unusual imaging morphology and imaging characteristics (distinctly low-signal on T2-weighted images) on MRI. An explanation for these features is proposed.

Adult↗
PubMed1995

Comparison of the results of cemented, porous-ingrowth, and threaded acetabular cup fixation. A meta-analysis of the orthopaedic literature.

A meta-analysis of the orthopaedic literature was performed to evaluate the clinical performance of cementless, threaded acetabular cups. The hypothesis for the study was that the clinical performance of the cementless, threaded acetabular cup is equivalent to that of the cemented and porous-ingrowth acetabular cups. Ninety-five articles were included in the study. There were 1,269 cases in the threaded cup group, 1,979 in the porous control group, and 10,230 in the cemented control group. The primary outcome variable tested was the rate of aseptic loosening of the acetabular components as measured by the revision rates following the index total hip arthroplasty procedure. Other measures of acetabular component loosening that were analyzed included clinical rating scores, pain scores, frequency of radiolucencies according to location and size, frequency of radiolucencies as a separately defined outcome variable, progressive radiolucencies, and component migration. The threaded cup group was found to have a significantly higher rate of revision, clinical and pain score failures, progressive radiolucencies and migrations when compared with the cemented and porous control groups (P < .05). Despite the many limitations of meta-analyses and the poor state of the orthopaedic literature database, this study provides a reasonable comparison of the clinical performance of threaded acetabular cups with that of cemented and porous-ingrowth acetabular cups.

Acetabulum↗
PubMed1995

Transcriptional activation of the macrophage-colony stimulating factor gene by minimally modified LDL. Involvement of nuclear factor-kappa B.

Minimally modified LDL (MM-LDL), obtained by mild iron oxidation or prolonged storage at 4 degrees C, has been shown to induce the expression of macrophage-colony stimulating factor (M-CSF) in cultured aortic endothelial cells. To examine whether other cell types also respond to MM-LDL, we investigated its effect on the expression of M-CSF mRNA in mouse L-cells and human aortic smooth muscle cells. Both L-cells and human aortic smooth muscle cells showed increased levels of M-CSF mRNA in response to 10 to 200 micrograms/mL MM-LDL in a dose-dependent manner. This allowed us to use mouse L-cells as a model to study the mechanism involved in MM-LDL-mediated increase in M-CSF mRNA. Nuclear runon assays showed that M-CSF gene transcription was activated by MM-LDL. In the present study, we identified specific elements that conferred MM-LDL-mediated transcriptional activation of the human M-CSF gene. Chimeric constructs containing sequential deletions in the 5'-promoter region of the M-CSF gene linked to a reporter chloramphenicol acetyltransferase (CAT) gene were transfected into mouse L-cells. The human M-CSF promoter region extending upstream from the transcription start site to nucleotide -406 showed maximum induction of CAT activity by MM-LDL. Induction of CAT activity was drastically reduced, with a deletion plasmid lacking the promoter region -406 to -344. A functional nuclear factor (NF)-kappa B binding site present in this critical region was required for MM-LDL-mediated induction of CAT activity since an internal deletion construct lacking this element showed significant loss of transcriptional activation.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1993

Hemiplegia in posterior cerebral artery strokes.

Hemiplegia is an unusual presenting feature of posterior circulation strokes. We report five cases who presented with hemiplegia and in whom CT scans revealed evidence of infarcts in posterior cerebral artery territory.

Adult↗
PubMed1991

Mold flora and aflatoxin contamination of stored and cooked samples of pearl millet in the Paharia tribal belt of Santhal paragana, Bihar, India.

Stored and cooked samples of pearl millet (Pennesetum typhoides), which is regularly consumed as food by the Paharia tribe in the hilly regions of Santhal Pargana, Bihar State, India, that were harvested in January 1989 were analyzed for mold flora, natural occurrence of Aspergillus flavus and A. parasiticus, and incidence and levels of aflatoxin B1. Of the 22 fungal species isolated, A. flavus and A. parasiticus were the predominant species (63.8%) during the rainy season, followed by other species of Aspergillus, Penicillium, Fusarium, Rhizopus, Helminthosporium, and Curvularia. Screening of 169 A. flavus and A. parasiticus strains showed that 59 of them were toxigenic, producing various combinations of aflatoxins B1, B2, G1, and G2. The amounts of aflatoxin B1 ranged between 4 and 30 mg/100 ml of liquid medium. Analysis of stored and cooked samples also revealed a high incidence and alarming levels of naturally produced aflatoxin B1. Forty-nine of 75 stored and 16 of 38 cooked samples contained various combinations of aflatoxins. The levels of aflatoxin B1 ranged between 17 and 2,110 ppb in stored samples and 18 and 549 ppb in cooked samples. The correlation of insect damage with A. flavus and A. parasiticus incidence and quantity of aflatoxin B1 was found to be insignificant.

Aflatoxin B1↗
PubMed1991

Extensive CT scan abnormality in Wilson's disease.

A case of Wilson's disease with extensive white matter hypodensity, including in the basal ganglia, on CT scan is presented. Such extensive CT scan abnormality has not been described in Wilson's disease.

Adolescent↗
PubMed1990

Cytologic screening for the detection of cancer in the uterine cervix--a survey in Patna (India).

Cytologic screening of the uterine cervix of 10,012 married women of Patna (India) was conducted to find out precancerous and cancerous lesions in different age and parity groups. Of the "pap" smears, 80.1% were normal, 11.1% were inflammatory, 5.8% showed dyskaryosis and 2.8% had cellular profiles suggestive of malignancy. In higher age groups i.e., in 40-49 and 50-59 years, the percentage of inflammatory smears were increased to 15 and 35.8; and invasive carcinoma to 8.28 and 14.19, respectively. Higher parity groups (four and above) had greater incidence of invasive carcinoma (6.7%) than those of lower parity groups (1.88%).

Adult↗
PubMed1990

Pancerebellar syndrome in hyperpyrexia.

Two cases of pancerebellar syndrome following hyperpyrexia are described and the relevant literature reviewed. Cranial computed tomography demonstrated morphologic evidence of cerebellar degeneration while the patients were showing satisfactory clinical progress.

Adult↗