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.

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.

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.

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.

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.

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.

Endoscopic and electroporation therapy of paranasal sinus tumors

The purpose of this article is to introduce the concept of endoscopic and electroporation therapy for the treatment of sinonasal carcinomas. Electroporation therapy is a technique that combines intralesional injection of bleomycin combined with application of high-voltage square wave electrical impulse into the tumor. A transient increase in cell membrane permeability allows intracellular entry of bleomycin, with subsequent cytotoxicity. Two cases of sinonasal cancer were treated with this technique. One patient had complete response and is free of disease at 20 months. The other had partial response with control of the disease up to a year. Endoscopic electroporation therapy is potentially a minimally invasive method for the treatment of sinonasal malignancies in an experimental setting where other treatment options do not exist. Phase II/III national clinical trials have been initiated to study the efficacy of electroporation therapy.

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.

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.

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.

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.