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Biomedical subjects

N Sadeghi

Publications and source records attributed to N Sadeghi.

At least 19 recordsLinked to original sources
PubMed2003

[Role of new MRI techniques in neuroradiologic practice].

Magnetic Resonance Imaging (MRI) has been introduced in clinical practice in the mid-eighties. However, MRI is an ever evolving imaging technique with constant new developments allowing broadening of clinical applications. In particular, angio-MRI involves many different acquisition techniques that will guide their clinical use. On the other hand, clinical applications of the following techniques are briefly discussed: diffusion, perfusion, tractography and diffusion tensor imaging, spectroscopy and functional imaging.

Brain Diseases↗
PubMed2002

Unusual CT features of dermoid cyst in the posterior fossa.

A dermoid cyst of the posterior fossa in a 73-year-old man is reported. The presentation of the cyst was unusual because of the age of the patient, the spontaneously hyperdense aspect of the mass on CT, the partial rim enhancement of the lesion, and the presence of perilesional edema. On pathologic examination, the cyst contained small amount of fat, hairs, necrosis, and small areas of hemorrhage. The amount of hemorrhage found could not explain the spontaneous hyperdensity of the lesion found on CT. The hyperdensity may be related to high protein content of the lesion.

Aged↗
PubMed2002

Stereologic assessment of the total cortical volume occupied by amyloid deposits and its relationship with cognitive status in aging and Alzheimer's disease.

Although the presence of amyloid deposits is required to establish the neuropathologic diagnosis of Alzheimer's disease, from a clinical point of view, a direct contribution of these cerebral lesions to cognitive deficits is still controversial. The development and standardization of quantitative and accurate biochemical and neuropathologic methods may be critical to improve the postmortem diagnosis and clinicopathologic correlations. Here, we used a point counting method, based on the Cavalieri principle, to estimate the volume occupied by amyloid deposits in a discrete region of the prefrontal cortex and in the hippocampal formation, in brains from patients with cognitive status ranging from normal to severely demented. We demonstrate that the assessment of the total volume occupied by the amyloid deposits in the entorhinal cortex and subiculum can be considered an effective predictor of dementia severity. We also reveal the existence of a high degree of regional and interindividual heterogeneity in amyloid distribution and relative volume. Our data suggest that even though a correlation was observed between the stereologic point counting method and a non-stereologic random field thresholding approach, in most cases non-stereologic methods may not provide adequate samples of the tissue and may lead to unreliable estimates of amyloid burden due to the inhomogeneous distribution of amyloid in the cerebral cortex and the large variability among brains.

Aged↗
PubMed2002

[The medical imaging and radiology department].

Technological developments arising from research have affected the whole wide spectrum of medical endeavor and have made a very significant impact on clinical practice and especially on imaging sciences. Ultrasonography brought spectacular advances, but CT and MRI became important landmark techniques. A further important development, which greatly increased the involvement of radiologists in direct patient management, was the growth of interventional and therapeutic techniques, called interventional radiology. Some statistics: approximately 155,000 patients per year including 19,000 CT Scans, 10,000 MRI exams, 21,000 ultrasound examinations and 1,000 therapeutic procedures. Some research activities: CT quantification of pulmonary emphysema, respiratory mechanics, MR and CT angiography, antenatal diagnosis of congenital and genetic diseases of the fetus, quantification of portal haemodynamics, MR imaging of bile and pancreatic ducts, morphologic and functional imaging of the brain, radiology of bone trauma, MR characterization in hepatic lesions.

Belgium↗
PubMed2001

Hereditary angio-edema involving the gastrointestinal tract: CT findings.

We report a case of hereditary angio-edema in a young man presenting with recurrent abdominal pain for many years. The diagnosis was suspected on the basis of abdominal CT performed during an abdominal attack and was then confirmed by the measurement of serum concentration of C1 esterase inhibitor (C1-INH). To our knowledge, this is the first case reported of the hereditary form of angio-edema with isolated abdominal pain and in which the diagnosis was suggested by abdominal CT findings.

Abdominal Pain↗
PubMed2001

Thermal blockage of viruslike particle formation for the yeast retrotransposon Ty3 reveals differences in the cellular stress response.

The long terminal repeat (LTR) retrotransposons of the yeast Saccharomyces cerevisiae are similar in their structures and life cycles to animal retroviruses. The yeast LTR retrotransposon Ty3 does not transpose under conditions where the cellular stress response is activated. During stress, mature Ty3 proteins, indicative of the formation of intracellular Ty3 viruslike particles (VLPs), do not accumulate. In order to examine the role of stress proteins in Ty3 transposition, a sensitive genetic assay was developed to measure VLP formation. The assay employs a Ty3 element marked with a mutant allele of the yeast HIS3 gene (his3AI). To create a stable His+ phenotype, Ty3 must form VLPs, reverse transcribe Ty3 RNA into cDNA, and then insert the cDNA into either chromosomal or plasmid DNA. Using this assay, thermal inhibition of Ty3 transposition was evident at temperatures as low as 30 degrees C. The level of production of mature Ty3 proteins parallels the transposition frequency. Although overexpression of the yeast UBP3 gene allows VLPs to form and transposition to occur in the constitutively stressed ssa1 ssa2 strain, it does not alleviate the inhibition of these processes during stress induced by heat or ethanol. This suggests that the genetic and physical modes of stress response induction are not equivalent.

Endopeptidases↗
PubMed2001

Bilateral chylothorax following neck dissection: a new method of treatment.

Chylothorax is a serious condition with a high rate of morbidity that may lead to death. Although it is encountered more frequently with certain thoracic procedures, it is considered to be a rare complication of neck dissection. Different forms of management have been postulated; however, no consensus of treatment has been achieved. A case of severe bilateral chylothorax that developed after bilateral neck dissection in a patient with laryngeal carcinoma is presented. Somatostatin injection was successful after total parenteral nutrition failed to control the chylothorax. On the basis of this case and the review of the literature discussed here, we advocate the use of somatostatin with other conservative measures in the management of chylothorax.

Aged↗
PubMed2000

MultiDimensional Voice Program analysis in children with vocal cord nodules.

Computer-assisted voice analysis has recently been introduced as a noninvasive approach to the management of paediatric dysphonia. The aim of this study was to determine which parameters of voice analysis distinguish vocal cord nodules from normal patterns. Following diagnosis by flexible nasolaryngoscopy, 12 male children with vocal cord nodules, aged 7 to 12, underwent voice analysis by MultiDimensional Voice Program (MDVP; Kay Elemetrics, Lincoln Park, NJ, USA). These subjects were divided into two age groups (7-9 years, n = 5; 10-12 years, n = 7) and compared to age-matched controls. Results suggest that across all age groups, subjects with vocal cord nodules had statistically significant (p < .01) elevations in absolute jitter, jitter percent, relative average perturbation, pitch period perturbation quotient, smoothed amplitude perturbation quotient, and fundamental frequency variation. Further studies are required to assess the role of MDVP in the diagnosis of other voice pathologies and the monitoring of voice therapy.

Child↗
PubMed1999

Cell cycle control of reverse transcriptase activity for the yeast retrotransposon Ty3.

Retroviruses and retrotransposons depend on their host cells to complete their replication cycles. In many cases, the viral step of reverse transcription is blocked when host cells are arrested in their cell cycle and this block is only released when the host cell resumes division. It has previously been shown that a retrotransposon found in Saccharomyces cerevisiae, Ty3, is unable to produce full-length double-stranded DNA, the product of reverse transcription, when the host cells are arrested in G1. In this study we show that, although Ty3 viruslike particles are produced at equivalent levels in arrested and nonarrested cells, the reverse transcriptase enzyme is inactive in arrested cells. The enzyme activity is restored when the arrested cells are permitted to resume cell division. These data suggest that a host factor regulates the activity of Ty3 reverse transcriptase in the cell cycle, which represents a novel cellular control of retroelements.

G1 Phase↗
PubMed1999

Right diaphragmatic rupture and hepatic hernia: an indirect sign on computed tomography.

We report a case of blunt traumatic right diaphragm rupture with hepatic hernia. The diagnosis was first suggested by an abnormal hepatic location depicted on axial CT. This finding can be considered as a potentially new indirect sign of right diaphragm rupture in patients with blunt trauma. The diagnosis was then confirmed by reformatted CT and MR images.

Accidents, Traffic↗
PubMed1997

Generation of therapeutic T cells from draining lymph nodes in a murine model of head and neck squamous cell carcinoma.

OBJECTIVES: To study immunotherapy for advanced head and neck squamous cell carcinoma using AT-84, a spontaneously arising murine tumor. We examined the draining lymph nodes (DLNs) for generation of potential therapeutic lymphocytes in head and neck squamous cell carcinoma. DESIGN: Experimental randomized control trial. INTERVENTION: Therapeutic T cells from DLNs were generated by the sequential activation of the in vivo-primed DLN cells with 2C11, and anti-CD3 antibody, and interleukin-2 (IL-2). Immunotherapy of mice bearing lung metastases was carried out in various experiments with low-dose systemic IL-2 and activated DLN cells. Using a 4-hour radioactive chromium Cr 51 release assay, in vitro cytotoxicity of these cells also was examined. RESULTS: Mice immunized with this tumor failed to reject the growth of a subsequent challenge with the tumor. Immunotherapy with low-dose systemic IL-2 resulted in a mean reduction of 79% in the number of lung metastases. Adoptive immunotherapy with activated DLN cells was effective in all experiments, with a mean reduction of 59% in the number of metastases in immunodeficient mice. However, DLN cells were not directly cytotoxic to the tumor cells in in vitro assays, unlike control lymphokine-activated killer cells. CONCLUSIONS: AT-84 is a nonimmunogenic tumor similar to many human malignant neoplasms, making this a suitable model for immunotherapy. Low-dose systemic IL-2 was effective in reduction of established metastasis in this model. Activated DLN cells show reproducible in vivo therapeutic efficacy despite lack of in vitro cytotoxicity. Use of DLN cells as sources of therapeutic T cells in patients with head and neck squamous cell carcinoma deserves exploration because they are readily obtainable and because conventional treatment is of limited benefit.

Animals↗
PubMed1996

Primary biliary cirrhosis and bone changes.

Two cases of primary biliary cirrhosis with bone lesions are reported. In one case radiographic findings in the hands and right shoulder are found to be characteristic of primary biliary cirrhosis rather than other concomitant diseases present in the patient which are also susceptible to produce bone lesions. The second case is an example of less specific bone changes which may be attributed to primary biliary cirrhosis or other rheumatoid disease.

Aged↗
PubMed1996

Parotidectomy for the treatment of chronic recurrent parotitis.

OBJECTIVE: To assess the success of superficial parotidectomy in the treatment of chronic parotitis (a potentially debilitating disease heralded by recurrent painful swellings) and purulent sialorrhea. DESIGN: A retrospective review. METHODS: Ten patients who were managed by superficial parotidectomy after failure of all conservative measures at the Department of Otolaryngology, McGill University were studied. RESULTS: Eight had complete resolution of their disease, and two had minor persistence on follow-up. None of them had permanent facial nerve injury. CONCLUSION: We therefore advocate superficial parotidectomy for this condition on failure of conservative measures.

Adolescent↗