Biomedical subjects
Publications and source records attributed to M R Macdonald.
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OBJECTIVE: To identify surface landmarks that can serve as reference points to the underlying musculature in the treatment of glabellar rhytids. METHODS: Fifty cadaver hemibrows were dissected to assess the location, disposition, and relationships of the brow muscles, along with their variations at each of several consistent locations. Particular attention was paid to the corrugator supercilii, frontal belly of the frontalis, and procerus muscles. CONCLUSIONS: The information gained here may be applied to the pharmacological or surgical treatment of glabellar rhytids. Knowledge of the frequent location of the muscles involved, relative to easily identifiable surface landmarks, allows a more precise approach.
BACKGROUND: The relationship between sinonasal inverted papilloma (IP) and various strains of human papilloma virus (HPV) has been examined previously. Yet there is little consensus regarding the incidence or role of HPV in IP. The possible role of Epstein-Barr virus (EBV), which, like HPV, is a DNA virus linked to human lymphoid and epithelial malignancies, was investigated. METHODS: The polymerase chain reaction (PCR) was used to detect EBV genomic sequences in surgical specimens of IP, in benign nasal polyps, and various control tissues. The IP specimens were similarly examined for the presence of HPV types 6, 11, 16, and 18. RESULTS: EBV DNA was found in 13 of 20 IP specimens (65%) and none of the 10 control tissues. Nine of the 20 specimens contained HPV DNA, and 5 of 20 specimens contained both EBV and HPV. CONCLUSIONS: These results imply a previously unsuspected role for Epstein-Barr virus in the pathogenesis of sinonasal inverted papilloma.
A recent case of ignition of a bismuth-subgallate pack during routine tonsillectomy prompted this investigation of local oxygen levels. Similar conditions were reproduced in the laboratory to determine their influence on the flammability of materials commonly used to aid in haemostasis. Cotton tonsil packs soaked in saline, adrenalin, or adrenalin and bismuth were compared. During spontaneous ventilation through an age-appropriate uncuffed endotracheal tube, an air leak rarely occurred. However, when assisted ventilation was used, an airway leak produced an elevated oxygen concentration in 8 of 10 children. This was associated with increased combustibility of the packs, regardless of solution mixture. The addition of bismuth further increased combustibility. Partially saturated packs appeared to be more combustible than fully saturated packs.
Carboplatin was introduced to the paediatric population as an alternative chemotherapeutic agent in the management of various malignant neoplasms, including sarcomas of the head and neck, in the hope that it would have fewer side effects than pre-existing agents. While many investigators have considered the ototoxicity of this drug only incidentally, others have presumed it to be of negligible importance. A recent animal model of its use has demonstrated damage to the inner hair cells of the cochlea, particularly at the basal turn, with a corresponding high incidence of hearing loss. Similarly, 11 of 22 patients who received this agent at the Hospital for Sick Children over the past 2 years demonstrated a sensorineural hearing loss in the 4 to 12 kHz range. This complication occurred as early as after the first dose and was generally progressively worse with subsequent doses. Consequently, we recommend careful audiologic monitoring of children receiving this agent.
An investigation of 10 critical care units recorded nurses' perceptions of the positive and negative aspects of their work settings.
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BACKGROUND: The patient with nasopharyngeal carcinoma (NPC) frequently is initially seen with regional node dissemination. Preliminary investigations suggest that the presence of Epstein-Barr virus (EBV) genomes in neck metastases from an occult primary may be diagnostic and predictive of NPC. The goal of this study was to test this proposition. METHODS: The polymerase chain reaction (PCR) was used to detect the presence of EBV DNA in fine-needle aspirate (FNA) samples obtained from malignant neck nodes. Control samples were obtained from other locations in the head and neck. PATIENTS: The patients in this study were evaluated at the Toronto Princess Margaret Hospital, a province-wide tertiary-care cancer treatment center. Of the 23 patients evaluated with malignant neck masses, 6 had NPC, 5 patients had metastatic squamous cell carcinoma of an unknown primary, and 12 patients served as controls with other known head and neck carcinomas. One of the patients initially diagnosed as an unknown primary later demonstrated NPC. FNA specimens were also obtained from 24 normal parotid, submandibular, or thyroid glands for comparison. RESULTS: In the samples with sufficient DNA for analysis, EBV was detected in 5 of 5 neck nodes from patients with known NPC. EBV was also detected in the neck node of a patient who went on to develop NPC and in a cervical node from 1 of 2 patients in whom the primary tumor remained unknown. None of the evaluable control neck nodes of FNA controls from other sites demonstrated EBV. CONCLUSIONS: These results demonstrate the utility of NPC-diagnostic EBV gene amplification in FNA samples of neck metastases and suggest that the presence of the EBV genome in FNA samples of neck nodes is predictive of the presence of NPC.
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