Evolutionarily Young African Rhinoceros Gammaretroviruses.

High-throughput sequences were generated from DNA and cDNA from four Southern white rhinoceros (Ceratotherium simum simum) located in the Taronga Western Plain Zoo in Australia. Virome analysis identified reads that were similar to Mus caroli endogenous gammaretrovirus (McERV). Previous analysis of perissodactyl genomes did not recover gammaretroviruses. Our analysis, including the screening of the updated white rhinoceros (Ceratotherium simum) and black rhinoceros (Diceros bicornis) draft genomes identified high-copy orthologous gammaretroviral ERVs. Screening of Asian rhinoceros, extinct rhinoceros, domestic horse, and tapir genomes did not identify related gammaretroviral sequences in these species. The newly identified proviral sequences were designated SimumERV and DicerosERV for the white and black rhinoceros retroviruses, respectively. Two long terminal repeat (LTR) variants (LTR-A and LTR-B) were identified in the black rhinoceros, with different copy numbers associated with each (n = 101 and 373, respectively). Only the LTR-A lineage (n = 467) was found in the white rhinoceros. The African and Asian rhinoceros lineages diverged approximately 16 million years ago. Divergence age estimation of the identified proviruses suggests that the exogenous retroviral ancestor of the African rhinoceros ERVs colonized their genomes within the last 8 million years, a result consistent with the absence of these gammaretroviruses from Asian rhinoceros and other perissodactyls. The black rhinoceros germ line was colonized by two lineages of closely related retroviruses and white rhinoceros by one. Phylogenetic analysis indicates a close evolutionary relationship with ERVs of rodents including sympatric African rats, suggesting a possible African origin of the identified rhinoceros gammaretroviruses. IMPORTANCE Rhinoceros genomes were thought to be devoid of gammaretroviruses, as has been determined for other perissodactyls (horses, tapirs, and rhinoceros). While this may be true of most rhinoceros, the African white and black rhinoceros genomes have been colonized by evolutionarily young gammaretroviruses (SimumERV and DicerosERV for the white and black rhinoceros, respectively). These high-copy endogenous retroviruses (ERVs) may have expanded in multiple waves. The closest relative of SimumERV and DicerosERV is found in rodents, including African endemic species. Restriction of the ERVs to African rhinoceros suggests an African origin for the rhinoceros gammaretroviruses.

Carbon nanoparticles neutralize carbon dioxide (CO2) in cytotoxicity: Potent carbon emission induced resistance to anticancer nanomedicine and antibiotics.

Excessive carbon emissions, especially CO2 release, have been a global concern. Few studies applied nanotechnology to relieve the ecotoxicity of CO2. Here, we applied carbon dots (CDs) to neutralize the CO2. We found CO2 induced the aggregation of CDs, which is of significance for CDs in enhanced fluorescence intensity but decreased CDs function in nanozyme activity, and reduced CDs toxicity to bacteria and cancer cells. Our data suggest the concern of CO2 release in global health in CDs mediated anticancer drug delivery and antibiotics resistance. However, enhanced fluorescence in cells which can be applied for bioimaging or CO2 sensing as simulated investigation by static charged attraction of positively charged CDs with negatively charged soluble HCO3-. Thus, CO2 abrogates the nanomedicine efficacy in cancer cells and antibacterial and may induce drug resistance for patients undergoing chemotherapy or antibiotics therapy. To overcome the resistance, we may apply the CDs for a neutralization of CO2 for impact on anticancer nanomedicine and antibiotics and reducing the ecotoxicity in biological systems.

Capacity Reconceptualized: From Assessment Tool to Clinical Intervention.

Capacity evaluation has become a widely used assessment device in clinical practice to determine whether patients have the cognitive ability to render their own medical decisions. Such evaluations, which might be better thought of as "capacity challenges," are generally thought of as benign tools used to facilitate care. This paper proposes that such challenges should be reconceptualized as significant medical interventions with their own set of risks, side effects, and potentially deleterious consequences. As a result, a cost-benefit analysis should be implemented prior to imposing such capacity challenges, and efforts should be made to minimize such challenges in situations where they are unlikely to alter the course of treatment.

Extensive Health Care Utilization and Costs of an Early Liver Transplantation Program for Alcoholic Hepatitis.

Early liver transplantation (LT) for severe alcoholic hepatitis (AH) is a rescue therapy for highly selected patients with favorable psychosocial profiles not responding to medical therapy. Given the expected increase of AH candidate referrals requiring complex care and comprehensive evaluations, increased workload and cost might be expected from implementing an early LT program for AH but have not been determined. Some centers may also view AH as a strategy to expeditiously increase LT volume and economic viability. The aim of this study was to determine the health care use and costs of an early LT program for AH. Analyses of prospective databases of AH, interhospital transfers, and the hospital accounting system at a single center were performed from July 2011 to July 2016. For 5 years, 193 patients with severe AH were evaluated at our center: 143 newly referred transfers and 50 direct admissions. Annual increases of 13% led to 2 to 3 AH transfers/month and AH becoming the top reason for transfer. There were 169 (88%) nonresponders who underwent psychosocial evaluations; 15 (9%) underwent early LT. The median cost of early LT was $297,422, which was highly correlated with length of stay (r = 0.83; P < 0.001). Total net revenue of the program from LT admission to 90 days after LT was -$630,305 (-5.0% revenue), which was inversely correlated with MELD score (r = -0.70; P = 0.004) and yielded lower revenue than a contemporaneous LT program for acute-on-chronic liver failure (ACLF; $118,168; 1.4% revenue; P = 0.001). The health care use and costs of an early LT program for AH are extensive and lifesaving with marginally negative net revenue. Significantly increasing care of severe AH patients over 5 years resulted in increased LT volume, but at a lower rate than ACLF, and without improving economic outcomes due to high MELD and prolonged length of stay.

Molecular evidence of tick-borne pathogens in Hyalomma anatolicum ticks infesting cattle in Xinjiang Uygur Autonomous Region, Northwestern China.

Although tick-borne pathogens have been widely reported in ticks in China, there is little information available on the prevalence of information in Hyalomma ticks from cattle. This study aims to determine the occurrence of pathogens in Hyalomma anatolicum collected from cattle in Xinjiang Uygur Autonomous Region, China, by PCR, sequencing and phylogenetic analysis. Borrelia burgdorferi s.s., Rickettsia massiliae and Anaplasma bovis were identified, whereas DNA of Ehrlichia species and an Anaplasma platys-like pathogen were also detected. Our findings highlight the risk of infection of animals and humans with these pathogens in north-western China.

Preadmission Screening and Resident Review (PASRR) regulation and its implications for patients, hospitals, nursing homes, and the taxpayers.

BACKGROUND: This study assessed the impact of the revision of the Preadmission Screening and Resident Review (PASRR) regulation changes in September 2011, which increased the turnaround time for PASRR evaluations from 3 to 5 days to 2 to 3 weeks. METHODS: From January 2013 to March 2013, we tracked all patients' charts in a 25-bed inpatient geriatric psychiatric unit in New York where PASRR evaluations were requested. The turnaround time and related issues were analyzed. RESULTS: There were 27 patients who had PASRR requests during the study period; 9 patients were not included in the study because of incomplete data. The average turnaround time for the 18 patients was 14.89 days and the additional hospital bed cost per patient was $11,911.11. CONCLUSIONS: Although PASRR has played a positive role in identifying persons with serious mental illness and the need to provide the services they need, the recent revision of the PASRR regulation in 2011 has significantly increased the hospital bed costs.

Fifteen-minute consultation: structured approach to management of a child with recurrent croup.

Recurrent croup is a distinct clinical entity from viral croup. It is not a specific diagnosis and its presence should alert the clinician to explore the underlying cause. We discuss an evidence-based structured approach to management of a child with recurrent croup.

Recurrent Severe Burns Due to Cannabinoid Hyperemesis Syndrome.

Cannabinoid hyperemesis syndrome (CHS) is one of the health outcomes of cannabis use that is showing an increase in the number of reported cases since it first emerged in the medical literature. It is a condition that is now frequently seen by many specialists, including consultation-liaison psychiatrists. CHS is a diagnosis of exclusion that is characterized by the presence of a prolonged history of daily cannabis use, cyclic episodes of nausea and vomiting, and frequent compulsive hot baths. It will be fairly argued that with the surge in the number of marijuana users and frequency of use since the legalization of marijuana in the United States, a proportionate rise in CHS cases is expected over time. In this case report, we present a unique case of a 36-year-old female diagnosed with CHS, and the compensatory behavior of compulsive hot baths led to repeated episodes of severe burns, sepsis, and intensive care unit (ICU) hospitalizations. To the authors' knowledge, this is the first published case of severe burns and sepsis as complications of cannabinoid hyperemesis syndrome.

Racial Disparities in Psychiatric Decisional Capacity Consultations.

OBJECTIVE: In this study, the authors examined potential disparities and biases in the placement and outcomes of decisional capacity evaluations across races, controlling for patient characteristics. METHODS: The authors reviewed 181 patient decisional capacity consultations requested for the consultation-liaison psychiatry service at a tertiary care medical center from 2018 to 2019. The racial distribution of patients in these consultations was compared with the racial distribution of hospital inpatient admissions from 2018 to 2019. The authors analyzed patient outcomes by using logistic regression that controlled for race, gender, age, education, primary insurance, type of capacity assessment, and psychiatric diagnosis. RESULTS: Decisional capacity consultations were placed disproportionately for Black (43% of consultations vs. 18% of total admissions) and Hispanic patients (26% of consultations vs. 21% of admissions) compared with White and Asian patients. Among 130 patients with a capacity determination, 95 (53% of total sample) were determined not to have capacity, an outcome that did not differ by race but was more likely to occur among patients diagnosed as having delirium. Sixty-seven patients with no capacity (37% of total sample) experienced a change in treatment, an outcome that was less likely to occur among Hispanic patients in the univariable analysis. CONCLUSIONS: Significant racial disparities were observed during the placement of a decisional capacity consultation. These findings reveal the potential biases introduced with both the initial challenge to a patient's capacity and the subsequent outcomes of the consultation. As such, the balance of risk versus benefit or utility of these consultations in certain populations must be carefully considered.

Ethical considerations for the use of artificial intelligence in medical decision-making capacity assessments.

The rapid advancement of artificial intelligence (AI) and machine learning are providing new tools to clinicians. AI tools have the potential to process vast amounts of data in a short amount of time, providing new insights and changing how we approach complicated healthcare problems. AI has the potential to assist clinicians in medical decision-making capacity assessments by providing additional insights to an evaluation process that currently lacks universal objective standards. However, despite the promise of AI in this setting, there remain significant concerns making it unlikely to replace human evaluators anytime soon. AI remains highly susceptible to biased inputs and thus biased decisions, raises questions about autonomy, and creates uncertainty for who is accountable for the ultimate decision of capacity. In this paper we explore these ethical considerations of using AI for capacity assessments. While we acknowledge AI may not be ready to replace physicians in determining patient medical-decision making capacity, these new technologies have significant near-term potential as a tool to screen patients, uncover physician biases, and guide next steps after a capacity determination has been made.

An Assessment of the Psychosocial Evaluation for Early Liver Transplantation in Patients With Acute Alcoholic Hepatitis in the Context of Alcohol Use Disorder, a Case-Control Study.

Background: Severe acute alcoholic hepatitis (AAH) has an extremely poor prognosis with a high short term mortality rate. As a result, many centers, including our own, have allowed transplant patients to be listed for transplantation prior to achieving 6-months of sobriety. Several scoring systems, designed to target patients with a minimal period of sobriety, have been proposed to identify patients with alcohol use disorder (AUD), who would be predisposed to relapse after liver transplantation. We investigated whether these scoring systems corroborated the results of the non-structured selection criteria used by our center regarding decision to list for transplant. Methods: We conducted a retrospective case-control study of 11 patients who underwent early liver transplantation for AAH matched with 11 controls who were declined secondary to low insight into AUD. Blinded raters confirmed the severity of the diagnosis of DSM-5 and scored the patients on a variety of structured psychometric scales used to predict alcohol relapse. These included the High Risk for Alcohol Relapse Scale (HRAR), Stanford Integrated Psychosocial Assessment Tool (SIPAT), Alcohol Relapse Risk Assessment (ARRA), Hopkins Psychosocial Scale (HPSS), Michigan Alcoholism Prognosis Score (MAPS), Alcohol Use Disorders Identification Test -Consumption (AUDIT-C), and Sustained Alcohol Use Post-Liver Transplant (SALT) scales. All patients who underwent transplantation were followed for harmful and non-harmful drinking until the end of the study period. Results: The transplant recipients had significantly favorable MAPS, HRAR, SIPAT, ARRA, and HPSS scores with cutoffs that matched their previous research. The SALT and AUDIT-C scores were not predictive of our selection of patients for transplantation. Despite an expedited evaluation and no significant period of sobriety, our case cohort had a 30% relapse to harmful drinking after an average of 6.6 years (5-8.5 years) of follow-up. Discussion: Despite the rapid assessment and the short to no period of sobriety, the patient cohort demonstrated a 30% relapse to harmful drinking, consistent with the 20% to 30% relapse to drinking rate reported after liver transplantation for all forms of alcoholic liver disease. Average scores from MAPS, HRAR, SIPAT, ARRA, and HPSS corroborated our current stratification procedures, with lower mean risk scores found in the transplanted group. Conclusion: Patients with AUD and severe AAH who obtain new insight into their disease and posses other favorable psychosocial factors have low rates of AUD relapse post-liver-transplantation. The psychosocial selection criteria for patients with alcoholic hepatitis in our institution are consistent with 4 of the 5 scoring systems investigated in their prediction of sobriety post-transplant.

Evidence of Resilience in Kidney Donors: A New York Statewide Cohort Analysis.

INTRODUCTION: Donor nephrectomy (DN) is a procedure performed to provide recipients with a kidney to treat end-stage renal disease. The following analysis evaluated depression diagnosis in DN patients compared to controls. METHODS: DN patients and matched controls were identified between 2000 and 2009 from the Statewide Planning and Research Cooperative System database. Cohorts were tracked for depression incidence. Multivariable logistic regression was used to determine independent predictors of a postoperative depression diagnosis. RESULTS: The total study cohort included 2108 DN cases and 2108 controls. In both donors and controls, the baseline rate of depression was 0.95% (n = 20). The 5-year incidence of depression diagnosis after exposure increased in both cohorts (donors: 2.5%, n = 53; controls: 7.2%, n = 152; P < .001). The 5-year relative risk for developing depression was 2.65 (CI 1.59-4.42, P = .0002) in donors and 7.60 (CI 4.79-12.07, P < .001) in controls. On multivariable regression, being a donor was associated with reduced risk of developing postoperative depression (OR = 0.322, CI 0.233-0.445, P < .001), and the greatest risk factor for postoperative depression was a prior depressive diagnosis (OR = 7.811, CI 3.814-15.997, P < .001). CONCLUSION: Our analysis shows that the strongest risk factor for depression was a prior diagnosis of depression. However, willingness to undergo donor nephrectomy is associated with less subsequent depression than the control population, suggesting that kidney donors may be a more resilient cohort.

Primary squamous cell carcinoma of the thyroid gland successfully treated with surgical resection and adjuvant chemoradiotherapy.

A 57-year-old woman presented with a 3-month history of an enlarging thyroid mass causing breathlessness and dysphagia. Cross-sectional imaging showed a thyroid tumour infiltrating the trachea and abutting the oesophagus. She underwent panendoscopy, total thyroidectomy and planned tracheal resection, but due to intraoperative findings, a staged procedure was planned instead. Histological analysis revealed a poorly differentiated squamous cell carcinoma (SCC) which was positive on paired box gene 8 (PAX8) immunostaining, suggesting a diagnosis of primary thyroid SCC. She subsequently underwent total laryngectomy and bilateral neck dissections followed by radiotherapy with concurrent cisplatin chemotherapy. The patient remains disease-free 22 months after treatment. Median overall survival is 10 months for macroscopically completely resected tumours. PAX8 immunostaining is a novel technique which helps with the diagnostic challenge of distinguishing between primary thyroid SCC and SCC metastatic to the thyroid from extrathyroidal sites. Complete surgical resection with adjuvant chemoradiotherapy may result in a favourable outcome despite conflicting reports in the literature.

Scoring systems to assess relapse risk in alcohol use disorder presenting for early liver transplantation: A systematic review.

OBJECTIVE: Early liver transplantation (LT) is considered for patients with alcohol use disorder (AUD) despite limited sober time when acute mortality risk from liver disease is high. The objective of this paper is to find psychosocial tools that do not rely on extended sober time and predict alcohol relapse post-LT. METHODS: We conducted a systematic review of Pubmed, Embase, and Scopus for studies testing psychosocial tools that used numeric scoring to predict post-LT alcohol relapse. Tools that afforded points for length of sobriety were excluded. Each study was analyzed for its clinical context, post-LT relapse outcomes and predictive validity. RESULTS: Five scoring systems across fourteen samples showed varied validity in predicting post-LT alcohol relapse. Relapse to any alcohol use after LT revealed an average relapse rate of 23%. Most scoring systems were understudied but four of five provided cut-off scores with high negative predictive values for relapse. CONCLUSION: Scoring systems may have a place in candidate selection but the data on cut-off scores and predictability are still lacking for their use alone in high stakes LT selection. Larger studies with prospective scoring and standardized follow ups for relapse post-LT will better allow the predictive validity of these psychosocial tools to be compared.

Poorly differentiated mucoepidermoid carcinoma of the thyroid.

Mucoepidermoid carcinomas (MECs) are the most common malignant tumour of the salivary glands. MECs have also been reported to occur in atypical sites. Primary MECs of the thyroid gland are extremely rare, accounting for 0.5% of thyroid malignancies with approximately 48 cases reported in the literature. In most cases, these are low-grade neoplasms with good long-term prognosis. We present the case of a 74-year-old patient with poorly differentiated MEC of the thyroid gland, which behaved aggressively resulting in rapid decline and death of the patient. The exact pathophysiology of the disease remains unclear and there is no consensus on the optimal treatment for this histological subtype. Recognition and diagnosis of this rare neoplasm are important as this can help guide optimal treatment, although in high-grade poorly differentiated cases, treatment options remain limited.

Identification of 12 Piroplasms Infecting Ten Tick Species in China Using Reverse Line Blot Hybridization.

Piroplasmosis, a disease of domestic and wild animals, is caused by tick-borne protozoa in the genera of Theileria and Babesia. There is limited information available about the prevalence of piroplasmosis in ticks in China, and to assess the potential threat of piroplasmosis in China, we investigated the infections of ovine and bovine Babesia and Theileria species in ticks collected from cattle, yaks, sheep, horses, and camels in several regions of China where tick-borne diseases have been reported. In total, 652 ticks were collected from the animals in 6 provinces of China. Babesia spp. and Theileria spp. were detected with a PCR-RLB method and identified by sequencing. Overall, 157 ticks (24.1%) were infected with 5 Babesia and 4 Theileria species. Among tested tick samples, 134 (20.6%) were single infections with 1 of 7 piroplasm species, with Theileria annulata (118/652, 18.1%) being dominant. Only 23 (3.5%) tick samples were double or triple infected, Theileria luwenshuni and Theileria sinensis (18/652, 2.8%) were frequently observed in co-infections. Some piroplasm species were carried by ticks that were not previously reported to be vectors.

Changes in teaching delivery by foundation doctors.

BACKGROUND: Contributing to the education of students as a junior doctor, with a busy rota, in an ever-evolving health care system can be challenging. METHODS: A 4-month timetable was organised to fit in with both the commitments of 60 foundation doctors and 120 final-year medical students. Using the already established online undergraduate timetable system, foundation doctors created regular sign-up teaching sessions for students to attend. Foundation doctors had their teaching assessed by senior colleagues, enabling work-based assessments to be completed and mapped to their curriculum. Feedback from both students and foundation doctors was collected using free-text answers and scale ratings. RESULTS: A total of 49 foundation doctors and 70 medical students were involved in the pilot teaching scheme. Using thematic analysis from the feedback, 76 per cent of foundation doctors reported an increased confidence in delivering teaching. In relation to the students, 75 per cent attended regular teaching sessions, 80 per cent found the teaching sessions relevant to their learning and preparation for final examinations, and 97 per cent would recommend this scheme to the next cohort of students. DISCUSSION: Teaching hospitals should encourage regular undergraduate teaching led by foundation trainees. Incorporating a flexible timetable and ensuring teacher availability can allow the delivery of high-quality teaching that is not only beneficial for the student but also for junior doctors keen to enhance their teaching ability. By being involved in regular teaching, junior doctors are able to build the skills, attitudes and practices of being competent clinical teachers, thereby preparing them to become the educators and trainers of the future.

Serious neonatal airway obstruction with massive congenital sublingual ranula and contralateral occurrence.

BACKGROUND: Congenital ranulas seldom occur, with bilateral presentation and prenatal diagnosis reported very rarely. We believe this is the first reported case of a neonate with a antenally diagnosed massive congenital ranula, who went on to develop a non-contiguous contralateral ranula, both contributing to obstruction in a complex paediatric airway. CASE REPORT: A female neonate was born to a non-primagravid mother via a planned elective caesarean section due to a lower facial defect and oral cyst. Antenatal aspiration of the pseudocyst was performed under ultrasound guidance with limited success. In the immediate post-natal period a poor airway was observed and the cyst was subsequently marsupialised. With the development of macroglossia secondary to oedema and tongue base collapse the airway was secured through surgical tracheostomy. A subsequent ultrasound scan revealed the presence of a second solitary cystic mass on the contralateral side. After careful excision of the contralateral pseudocyst, tongue function improved, with the resolution of a safe airway which permitted successful decannulation. A planned definitive procedure antenatally did not result in the anticipated improvement in function. However the subsequent development of a second non-contiguous pseudocyst and further surgical management resulted in a safe airway, improved masticator function and the ability to thrive. CONCLUSIONS: The prenatal diagnosis of congenital ranulas have been seldom reported, with no reported cases of contralateral occurrence and airway obstruction from an intraoral ranula. This rare case highlights the need for a well considered contingency plan when surgery is required for a neonatal airway at risk.

Genetic characterization and molecular survey of Babesia bovis, Babesia bigemina and Babesia ovata in cattle, dairy cattle and yaks in China.

BACKGROUND: Babesiosis is an important haemoparasitic disease, caused by the infection and subsequent intra-erythrocytic multiplication of protozoa of the genus Babesia that impacts the livestock industry and animal health. The distribution, epidemiology and genetic characterization of B. bigemina, B. bovis, and B. ovata in cattle in China as well as the prevalence of these protozoan agents were assessed. METHODS: A total of 646 blood specimens from cattle, dairy cattle and yaks from 14 provinces were collected and tested for the presence of the three Babesia species via a specific nested PCR assay based on the rap-1 and ama-1 genes. The PCR results were confirmed by DNA sequencing. Gene sequences and the genetic characterization were determined for selected positive samples from each sampling area. RESULTS: Of a total of 646 samples, 134 (20.7 %), 60 (9.3 %) and 10 (1.5 %) were positive for B. bovis, B. bigemina and B. ovata infections, respectively. Mixed infections were found in 7 of 14 provinces; 43 (6.7 %) samples were infected with B. bovis and B. bigemina. Three samples (0.5 %) exhibited a co-infection with B. bovis and B. ovata, and 6 (0.9 %) were infected with all three parasites. The rap-1a gene of B. bovis indicated a high degree of sequence heterogeneity compared with other published rap-1a sequences worldwide and was 85-100 % identical to B. bovis rap-1a sequences in Chinese isolates. B. bigemina rap-1c and B. ovata ama-1 genes were nearly identical, with 97.8-99.3 % and 97.8-99.6 % sequence identity, respectively, in GenBank. CONCLUSIONS: Positive rates of B. bovis and B. bigemina infection are somewhat high in China. The B. bovis infection in yaks was first reported. The significant sequence heterogeneity in different variants of the rap-1a gene from Chinese B. bovis isolates might be a great threat to the cattle industry if RAP-1a protein is used as immunological antigen against Babesia infections in China. The data obtained in this study can be used to plan effective control strategies against babesiosis in China.

Escherichia coli positive infratentorial subdural empyema secondary to mastoiditis and underlying cholesteatoma.

Infratentorial subdural empyema is a neurosurgical emergency that is associated with an alarmingly high morbidity and mortality if appropriate management is delayed. It is an important differential to consider when confronted with a patient with a reduced Glasgow Coma Scale, focal neurology and symptoms of raised intracranial pressure in the presence of a head and neck infection. It is also important that the primary team managing these patients is aware of the many pathogens that may be involved, including Escherichia coli. Early recognition, prompt diagnosis, timely involvement of the appropriate multidisciplinary teams, including neurosurgery, otorhinolaryngology, radiology and microbiology should be sought, and urgent intervention are imperative in avoiding a fatal outcome. This article presents a case of E coli-positive infratentorial subdural empyema secondary to mastoiditis due to underlying cholesteatoma, and a review of the pertinent literature.