Loop mediated isothermal amplification (LAMP) for the detection and subtyping of human papillomaviruses (HPV) in oropharyngeal squamous cell carcinoma (OPSCC).

BACKGROUND: Human papillomavirus (HPV)-related oropharyngeal squamous cell carcinoma (OPSCC) is a growing problem that presents a significant challenge to Otolaryngologist-Head and Neck Surgeons. Knowledge of HPV status yields critical prognostic information, with potential for treatment selection based on tumour HPV status. The current gold standard of diagnosis, PCR, is expensive, demanding and time consuming. Alternatives such as p16 immunohistochemistry are subjective and potentially inaccurate. Loop-mediated isothermal amplification (LAMP) is a rapid, robust and inexpensive molecular diagnostic technique. OBJECTIVES: Our aim was to verify LAMP as a potential bedside diagnostic assay for subtyping of HPV in OPSCC. STUDY DESIGN: DNA from 72 formalin-fixed paraffin embedded (FFPE) OPSCC patient samples was tested. PCR and LAMP were then performed to specifically identify HPV 16, 18, 31, 33 and 35. RESULTS AND CONCLUSIONS: For these high-risk subtypes, LAMP had an overall sensitivity of 99.4% and specificity of 93.2% relative to PCR. LAMP is a promising technology that can accurately diagnose high-risk HPV infection.

MRI texture analysis predicts p53 status in head and neck squamous cell carcinoma.

BACKGROUND AND PURPOSE: Head and neck cancer is common, and understanding the prognosis is an important part of patient management. In addition to the Tumor, Node, Metastasis staging system, tumor biomarkers are becoming more useful in understanding prognosis and directing treatment. We assessed whether MR imaging texture analysis would correctly classify oropharyngeal squamous cell carcinoma according to p53 status. MATERIALS AND METHODS: A cohort of 16 patients with oropharyngeal squamous cell carcinoma was prospectively evaluated by using standard clinical, histopathologic, and imaging techniques. Tumors were stained for p53 and scored by an anatomic pathologist. Regions of interest on MR imaging were selected by a neuroradiologist and then analyzed by using our 2D fast time-frequency transform tool. The quantified textures were assessed by using the subset-size forward-selection algorithm in the Waikato Environment for Knowledge Analysis. Features found to be significant were used to create a statistical model to predict p53 status. The model was tested by using a Bayesian network classifier with 10-fold stratified cross-validation. RESULTS: Feature selection identified 7 significant texture variables that were used in a predictive model. The resulting model predicted p53 status with 81.3% accuracy (P < .05). Cross-validation showed a moderate level of agreement (κ = 0.625). CONCLUSIONS: This study shows that MR imaging texture analysis correctly predicts p53 status in oropharyngeal squamous cell carcinoma with ∼80% accuracy. As our knowledge of and dependence on tumor biomarkers expand, MR imaging texture analysis warrants further study in oropharyngeal squamous cell carcinoma and other head and neck tumors.

Health care delivery for head-and-neck cancer patients in Alberta: a practice guideline.

BACKGROUND: The treatment of head-and-neck cancer is complex and requires the involvement of various health care professionals with a wide range of expertise. We describe the process of developing a practice guideline with recommendations about the organization and delivery of health care services for head-and-neck cancer patients in Alberta. METHODS: Outcomes of interest included composition of the health care team, qualification requirements for team members, cancer centre and team member volumes, infrastructure needs, and wait times. A search for existing practice guidelines and a systematic review of the literature addressing the organization and delivery of health care services for head-and-neck cancer patients were conducted. The search included the Standards and Guidelines Evidence (sage) directory of cancer guidelines and PubMed. RESULTS: One practice guideline was identified for adaptation. Three additional practice guidelines provided supplementary evidence to inform guideline recommendations. Members of the Alberta Provincial Head and Neck Tumour Team (consisting of various health professionals from across the province) provided expert feedback on the adapted recommendations through an online and in-person review process. Selected experts in head-and-neck cancer from outside the province participated in an external online review. SUMMARY: The recommendations outlined in this practice guideline are based on existing guidelines that have been modified to fit the Alberta context. Although specific to Alberta, the recommendations lend credence to similar published guidelines and could be considered for use by groups lacking the resources of appointed guideline panels. The recommendations are meant to be a guide rather than a fixed protocol. The implementation of this practice guideline will depend on many factors, including but not limited to availability of trained personnel, adequate funding of infrastructure, and collaboration with other associations of health care professionals in the province.

The prognostic impact of a combined carbonic anhydrase IX and Ki67 signature in oral squamous cell carcinoma.

BACKGROUND: Tumour hypoxia is associated with impaired apoptosis, resistance to therapy and poor prognosis. We previously reported that high stromal expression of the endogenous marker of hypoxia, carbonic anhydrase IX (CAIX), is associated with significantly reduced survival in oral squamous cell carcinoma (OSCC). In addition to hypoxia, CAIX expression is regulated by proliferation-associated signalling. We hypothesised that incorporating Ki67, a proliferation marker, into our existing CAIX-based stratification of OSCC would identify patients with the least favourable prognosis. METHODS: Surgically resected tumours from 60 OSCC patients were analysed for CAIX, Ki67 and BAX expression using fluorescence immunohistochemistry and automated quantitative analysis (AQUA). RESULTS: In patients expressing high stromal CAIX (sCAIX), stratification by tumour Ki67 expression revealed significantly distinct survival outcomes (P=0.005). In our OSCC cohort, below-median Ki67 and top-quartile sCAIX expression (Ki67(lo)sCAIX(hi)) were associated with significantly worse disease-specific survival in univariate (HR 7.2 (2.5-20.4), P=0.001) and multivariate (HR 4.2 (1.4-12.8), P=0.011) analyses. Hypoxia is associated with decreased BAX expression; the Ki67(lo)sCAIX(hi) group was more strongly associated with low BAX expression than high sCAIX alone. CONCLUSION: These data suggest that combined analysis of tumour Ki67 and sCAIX expression may provide a more clinically relevant assessment of tumour hypoxia in OSCC.

Investigation of skeletal muscle denervation and reinnervation using magnetic resonance spectroscopy.

OBJECTIVE: To determine changes in skeletal muscle metabolism after nerve transection and repair and to correlate metabolic changes with functional recovery. STUDY DESIGN AND SETTING: Male Wistar rats were divided into 6 experimental groups plus a control group. The posterior tibial nerve was transected and reapproximated. At varying times after surgery (1, 2, 4, 6, or 8 weeks) animals were sacrificed, the gastrocnemius muscle was harvested, and proton nuclear magnetic resonance (NMR) spectroscopy was performed. Functional recovery was measured using the sciatic function index. RESULTS: Animals undergoing nerve repair all showed functional recovery whereas the nonrepaired nerve group did not. Concentration of glucose and lactate increased after denervation and then returned toward normal. Choline concentration decreased and then returned toward normal. In animals not undergoing nerve repair, the metabolic abnormalities persisted and showed no sign of recovery over the 8-week observation period. CONCLUSIONS: 1H NMR spectroscopy is a potentially useful tool to study changes in skeletal muscle metabolism after motor nerve injury. SIGNIFICANCE: NMR spectroscopy is rapidly developing into a clinically useful tool. High-field magnets have improved resolution and data acquisition. Basic experiments, such as those described here, will help guide the use of NMR spectroscopy in clinical medicine and will also lead to a better understanding of basic mechanisms of nerve injury and repair.

Intraoperative magnetic resonance imaging for skull base surgery.

OBJECTIVES/HYPOTHESIS: Skull base surgery has evolved over the past several decades. Major improvements in the imaging of skull base pathology led to better target localization and better surgical planning. The objectives of this study were to assess the use of intraoperative magnetic resonance (MR) imaging in the management of a series of patients with skull base pathology. We hypothesized that high-quality intraoperative MR imaging would have an impact on surgery in this patient group. STUDY DESIGN: Prospective, non-randomized, cohort study. METHODS: Thirty-one patients with skull base lesions underwent surgery in a 1.5-Tesla intraoperative MR suite. The concepts of a moving magnet, high magnetic field strength, and radiofrequency coil design are presented. RESULTS: Eleven of 31 patients had the course of surgery significantly altered by the information acquired from the images obtained during surgery. CONCLUSIONS: Intraoperative MR imaging is a valuable adjunct to skull base surgery. One third of patients had altered surgery as a result of this adjunct. Intraoperative MR imaging is of particular value in the treatment of pituitary adenomas and benign skull base tumors.

Screening for cerebellopontine angle tumours: conventional MRI vs T2 fast spin echo MRI.

BACKGROUND: Unilateral audiovestibular symptoms are commonly seen in clinical practice and are rarely caused by retrocochlear pathology. However, clinicians are often required to rule out potentially serious causes of these unilateral symptoms. Gadolinium enhanced magnetic resonance imaging (GdMRI) is the most accurate test for detecting small cerebellopontine angle lesions and also screens the adjacent CNS structures. Its main disadvantage is the cost of the procedure. METHODS: We studied 100 consecutive patients with both GdMRI and a newer MRI screening study utilizing unenhanced T2-weighted fast spin echo (fse) MRI. Acquired images were randomly assessed by a panel of three neuro-radiologists. RESULTS: We found that the screening (fse) MRI was as sensitive and specific when detecting cerebellopontine angle tumors. CONCLUSIONS: We conclude that T2-weighted fse MRI is a safe and cost-effective alternative to GdMRI and offers better diagnostic utility when compared to auditory brain stem response (ABR) and CT scans.

Braking of expiratory airflow in obese pigs during wakefulness and sleep.

Braking of expiratory airflow is a phenomenon prominently seen in neonates where it is thought to defend end-expiratory lung volume. This paper describes pronounced expiratory braking in an adult animal, the obese Vietnamese pot-bellied pig. Three obese pigs were chronically instrumented for recording of intrapleural pressure and bioelectric signals related to sleep. Airflow was measured by a pneumotachograph attached to a facemask. Expiratory airflow resistance was calculated for 10 consecutive expirations during wakefulness, NREM, and REM sleep. All animals demonstrated a biphasic expiratory flow pattern characterized by an initial plateau in flow at a low value followed by a rapid increase later in expiration. Airflow resistance during early expiration was on average four-fold higher than during late expiration. A striking observation was the maintenance of pronounced expiratory braking during NREM and REM sleep. Expiratory braking in these animals is likely due to laryngeal mechanisms and may serve to preserve end-expiratory lung volume or improve hemodynamics.

Screening strategies for neonatal hearing loss: which test is best?

OBJECTIVE: The objective of this study was to evaluate the accuracy and cost effectiveness of three different methods of hearing screening in newborns. DESIGN: A prospective, randomized cohort design was used. One hundred and five newborns were tested in this preliminary study. SETTING: The study was conducted in a tertiary care hospital setting in both the well baby and special care nurseries. METHODS: Consenting subjects had their hearing tested using automated auditory brainstem response (AABR), distortion-product otoacoustic emissions, and click-evoked otoacoustic emissions. The time to perform the tests was recorded and the cost of each test was calculated. MAIN OUTCOME MEASURES: The main outcomes measured were the time taken to perform each test, the pass/fail rate for each test, and the estimated cost of the tests. RESULTS: In this small cohort of patients, we found that AABR was the most accurate test, but it took longer to perform and was more expensive than either of the otoacoustic emission tests. However, the sensitivity and specificity of otoacoustic emissions were less than that of AABR. Test time decreased as the examiner gained experience, and we anticipate that experience will also result in better accuracy for the otoacoustic emission tests. CONCLUSIONS: Hearing screening in a hospital-based newborn population is both feasible and cost effective. Although AABR was more expensive, its better accuracy must be considered. As technology improves, the cost of all three tests will diminish. More robust conclusions cannot be made based on this small patient population.

Monitoring respiratory function and sleep in the obese Vietnamese pot-bellied pig.

Development of drug treatments for obstructive sleep-disordered breathing has been impeded by the lack of animal models. The obese pig may be a suitable animal model, as it has been reported to experience sleep-disordered breathing resembling human obstructive sleep apnea. The purpose of this paper is to describe in detail techniques for chronic instrumentation of the obese Vietnamese pot-bellied pig and to study respiratory function during sleep. Under general anesthesia, four obese pigs were instrumented for long-term recording of intrapleural and tracheal pressures, genioglossal EMG, and bioelectric signals related to sleep. A custom-fitted face mask was used to record respiratory variables including airflow, snoring, and expired CO(2). Most chronic instrumentation provided robust signals for up to 6 wk after installation. All pigs displayed sleep-disordered breathing characterized by increased resistance to airflow, snoring, inspiratory flow limitation, and possible sleep disruption. Apneas and hypopneas were not a feature of breathing during sleep in these animals. Nonetheless, this animal preparation may be useful for exploring possible drug treatments for obstructive sleep-disordered breathing.

Fine needle aspiration biopsy findings in lymphoepithelial carcinoma of salivary gland.

OBJECTIVE: To study the fine needle aspiration cytology of lymphoepithelial carcinoma of salivary gland (LECSG). STUDY DESIGN: Needle aspirates from five primary and two metastatic LECSGs were reviewed. RESULTS: Three aspirates showed very scant cellularity with rare tumor cells originally misinterpreted as lymphohistiocytic cells. Six fine needle aspiration biopsies (FNABs) contained medium to large polygonal and spindled cells with one or more prominent nucleoli. Five aspirates also displayed a heterogeneous population of lymphoid cells, while a sixth had much necrotic debris and only a few lymphocytes admixed with tumor cells. CONCLUSION: In the clinical setting of an Inuit or Chinese patient with a salivary gland mass, an FNAB with these features should suggest the possibility of LECSG.

Asymmetric hearing loss: toward cost-effective diagnosis.

OBJECTIVE: Unilateral audiovestibular symptoms are commonly seen in clinical practice, and the treating physician frequently considers retrocochlear disease in the differential diagnosis. These considerations often precipitate a lengthy and expensive battery of tests. This study was conducted to evaluate the diagnostic yield of the various tests available in the investigation of these symptoms and to recommend changes to practice patterns, if appropriate. METHODS: We examined a cohort of 310 patients with unilateral audiovestibular symptoms who were referred to our radiology department for investigation. All patients had complete auditory assessments, and 144 underwent auditory evoked potential testing (ABR). There were 258 contrast-enhanced CT (CECT) scans and 86 gadolinium-enhanced MRI (Gd-MRI) scans performed. RESULTS: A total of 12 cerebellopontine angle (CPA) tumours were diagnosed. CONCLUSIONS: MRI is the diagnostic tool of choice in patients with asymmetric sensory neural hearing loss (ASHL), but it is expensive and not always easily available. Analysis of diagnostic accuracy of CECT and ABR, both used as screening tests, demonstrate their limitations and reveals that CECT is no more accurate than ABR, although it is three times more costly. Based on these data, we have changed our diagnostic approach to patients with unilateral audiovestibular symptoms. Patients are either evaluated with MRI or are screened initially with ABR based on clinical suspicion. CECT is no longer routinely included in the evaluation of patients with ASHL. Finally, newer emerging MRI techniques promise faster and less expensive examinations with increased diagnostic accuracy.

Magnetic resonance imaging of the extratemporal facial nerve of the rat.

OBJECTIVE: Magnetic resonance imaging (MRI) is an evolving technology that is being investigated for application in the study of the facial nerve. At the present time the majority of investigators use paramagnetic contrast agents, and the clinical utility of MRI for evaluation of facial paralysis is unproved. This study investigated both normal and injured rat facial nerves without contrast enhancement. METHOD: Anatomic dissection and histologic studies were performed to better define the location of the facial nerve. A surface coil was used to improve image resolution. RESULTS: Proton-weighted images showed that the normal facial nerve was a solid structure while the injured facial nerve was bright on T2-weighted images. CONCLUSION: MRI is a potentially useful method of investigating patients with facial nerve dysfunction. Further research is needed to clarify its role.

Biochemical changes in denervated muscle identified by magnetic resonance spectroscopy.

OBJECTIVE: Magnetic resonance spectroscopy (MRS) has the potential to noninvasively delineate early biochemical changes in denervated muscle. In this study, we examine metabolic changes in denervated rat facial muscles using quantitative invitro 1H and 31P MRS. METHODS: Forty male Wistar rats were subjected to transection of the facial nerve trunk on the left and sham exposure on the right, and allowed to recover. The animals were then reoperated at 1, 2, 4, or 8 weeks after the initial procedure. EMG of the facial muscles and facial nerve conduction studies were performed at both time points, and facial muscles were harvested from normal and control sides at the second procedure. Perchloric acid extracts of facial muscles were then prepared for analysis using MRS. RESULTS: The results showed a progressive time-dependent decrease in Cr, PCr, Pi, ATP, and ADP all on the transected side. CONCLUSION: This study is an important step in the development of clinically relevant noninvasive methods of assessing and quantifying degeneration in nerve-muscle systems.

Posttraumatic macroglossia complicated by hyaluronidase injection.

A patient with posttraumatic macroglossia has been presented. A literature review reveals that this is a rare sequela of tongue injury and is usually of acute onset. The delayed symptom of swelling in this patient and the exacerbation of swelling in association with hyaluronidase suggest a causal relationship between the two events. Macroglossia has not been reported in association with hyaluronidase injection, and it is recommended that the drug not be used to treat swelling after tongue injury.

Nonmetallic foreign bodies of the skull base: a diagnostic challenge.

Cases of physical trauma have become more common in emergency departments, since life in modern society has become increasingly dangerous. Foreign bodies in the head and neck region are more common, therefore, and management principles are well-defined. Typically, these foreign bodies are metal, plastic, or glass and often easily diagnosed; however, wooden foreign bodies pose special problems for the physician and, therefore, warrant separate consideration. We present the case of a 21-year-old male who was stabbed in the submental region with a large wooden stake and discuss the surgical and follow-up treatment of this interesting case, including the roles and limitations of angiography, computerized tomography, and magnetic resonance imaging.

Unilateral vestibular deafferentation: a model of adaptation.

After acute loss of peripheral vestibular function, a centrally adaptive process takes place. Clinical measurements of vestibular adaptation are useful, both diagnostically and as a means of following patients after acute vestibular deficits. Ocular torsion is one measurement that can be used to follow these acutely disabled patients. The measurement is made from fundus photographs and is technically easy to perform and interpret. We present a pilot study from our Vestibular Disorders Clinic using fundus photography to measure the optic nerve head-foveal angle in six patients undergoing unilateral vestibular neurectomy, with subsequent analysis resulting in a speculative mathematical model of vestibular compensation in the roll plane. While the identification or selection of patients with significant ocular torsions from the vestibular population remains ill-defined, fundus photography remains an easy and useful method of following compensation in postoperative patients.