Female Surgical Ergonomics in Otolaryngology: A National Survey Study

OBJECTIVE

To assess the nature and impact surgical ergonomic challenges experienced by female otolaryngologists.

STUDY DESIGN

National survey study.

SETTING

Female otolaryngology residents, fellows and attendings recruited via social media posting and email distribution.

METHODS

We distributed a survey study to female otolaryngologists throughout the United States. The height and glove size of participants reporting difficulties with equipment and instruments were compared to those not reporting difficulties.

RESULTS

Ninety-six female otolaryngologists participated in our study, comprised of 43% residents, 10% fellows, and 47% attendings. Ninety percent of participants reported difficulties using equipment and 77% of participants reported difficulty with instruments, the most common being nasal endoscopic instruments (28%). The vast majority of participants reported pain during and (or) after the operation (92%). Head and neck (53%) and rhinology (44%) were identified as particularly challenging specialities, but only 25% of participants reported that ergonomics affected their career plans. Participants felt that adjustable equipment (60%), a variety of sizes of instruments (43%), and more discussion around ergonomics (47%) would help. Respondents reported adjusting the operating room to accommodate their size took extra time (44%) and was a mental burden (39%). Participants reporting difficulties with operating room equipment were significantly shorter than those without difficulties (64 inches vs 67 inches, P = .037), and those reporting difficulties with instruments had a smaller median glove size (6 vs 6.5, P = .018).

CONCLUSION

Surgical ergonomics represent a challenge for female otolaryngologists, particularly those with smaller hands and shorter height. Partnering with industry, we must address the needs of an increasingly diverse workforce to ensure that all surgeons can operate effectively and comfortably.

Propensity score matched analysis and risk stratification of donors with G6PD deficiency in living donor liver transplantation

INTRODUCTION

Glucose 6 phosphate dehydrogenase (G6PD) deficiency (G6PDd) can trigger hemolysis following surgical stress. Differentiating G6PDd-related post-operative hemolytic episodes (PHE) and post-hepatectomy liver failure may be challenging especially in living donors where donor safety is paramount. We analysed outcomes of our cohort of G6PDd liver donors.

METHODS

G6PDd individuals with no evidence of hemolysis were considered as living donors if there was no alternative family donor. Outcomes of G6PDd donors undergoing left lateral/left lobe donation (Group LL) and right lobe donation (Group RL) were compared with non-G6PDd donors matched in a 1:3 ratio using propensity score matching.

RESULTS

59 G6PDd donors (5.8% of 1011) underwent living donor hepatectomy (LiDH) during the study period. LL-G6PDd donors (22.37%) had higher post-operative peak bilirubin level compared to matched controls, but no difference in morbidity or need for post-operative blood transfusion.RL-G6PDd donors (37.63%) had higher peak bilirubin level, morbidity (16.2% vs. 3.6%, p = 0.017) and more post-operative blood transfusion (21.6% vs. 6.4%, p = 0.023) as compared to matched non-G6PDd cohort. Four RL-G6PDd donors (10.8%) developed PHE. Low G6PD activity (15% vs. 40%, p = 0.034) and lower future liver remnant (FLR) (34.3% vs. 37.8%, p = 0.05) were identified as risk factors for PHE.

CONCLUSION

We report the largest to-date series of G6PDd individuals undergoing LiDH and confirm the safety of LL donation in G6PDd. Our analysis identifies specific risk factors for PHE and suggests that right lobe LiDH be avoided in individuals with less than 25% G6PD activity when the FLR is less than 36%.

More Than 1 Way to Put in A T-Tube: A Review of Different Techniques Used in Insertion of Montgomery T-Tubes

OBJECTIVE

The Montgomery T-tube is a commonly used device initially designed as a temporary airway stent, but also used as a long-term airway solution for stenosis. For patients undergoing either endoscopic or open airway procedures, proper techniques for inserting these tubes are well documented. This review compiles the techniques used for insertion of the Montgomery T-tube stent.

METHODS

The NCBI Pubmed database was queried using the keywords: "stent," "Montgomery," "T-tube," "stenosis," "technique." A total of 33 papers were reviewed with 12 papers selected for the study. Papers were selected based on inclusion criteria of English language and whether the paper described a technique for insertion of a Montgomery T-tube into the airway. Papers were excluded if they did not describe the technique of insertion of Montgomery T-tubes or dealt with another aspect of T-tube management.

RESULTS

The 12 selected papers each described a different technique for insertion of a Montgomery T-tube stent. Though nearly all the selected studies described using a modified Seldinger technique for insertion of the T-tube, there were discrepancies and a wide array of different instruments used. The instrument and/or technique that was selected was often determined by the individual need of the patient. Several studies addressed the challenge of interrupting ventilation while inserting or exchanging a T-tube in the operating room. These studies described attaching the T-tube to the endotracheal tube to pass the T-tube into the airway while allowing for continuous ventilation. Yet other studies used optical forceps or rigid bronchoscopes to allow placement of the T-tube with direct visualization.

CONCLUSION

There are many techniques used for the insertion of a Montgomery T-tube. Nearly all studies described using a modified Seldinger technique and all the studies agreed on the necessity of a team approach for placement of the Montgomery T-tube.

Chronic Refractory Cough: Long-Term Outcomes Following Cough Suppression Therapy

OBJECTIVE

This study aimed to determine the long-term outcomes of patients with chronic refractory cough (CRC) following treatment for cough suppression therapy (CST). Currently, there is a lack of objective data regarding the long-term outcome of behavioral treatment for CRC.

METHODS

From the charts of 106 adult patients diagnosed with CRC, 24 patients were identified as having long-term data at least 3 months post-CST in the form of otolaryngologic examination, Voice Handicap Index-10 (VHI-10), and Cough Severity Index (CSI) scores. Patients underwent otolaryngologic evaluation and completed the VHI-10 and CSI assessments during pretreatment, posttreatment, and long-term follow-up visits. Patients were also divided into two groups based on their number of comorbidities.

RESULTS

Twenty of the 24 patients had significant reduction in cough severity after completing CST (P < 0.001). A significant difference was also found in CSI scores from pretherapy to the long-term follow-up visits (P = 0.001). No significant difference was found in CSI scores from posttherapy to long-term follow-up visits (P = 0.93). No significant difference was found in VHI-10 scores over time (P = 0.83). No correlation was found between changes in cough and voice severity and number of comorbidities at the tested level.

CONCLUSIONS

Findings of no significant change in CRC over the long term compared to posttherapy measures suggest that patients were able to maintain improvement in cough over the long term despite various comorbidities. The current results suggest that CST represents a satisfactory approach to treating CRC and provides patients with an ongoing tool to maintain reduced cough severity. No significant correlations between number of comorbidities and mean CSI or VHI-10 scores were found over the long term.

The Diagnosis and Time of Onset of Voice Disorders in Patients with Chronic Cough

OBJECTIVES

Chronic cough is a complaint of up to 46% of patients referred to specialist clinics. Patients with cough often report hoarseness at the time of the cough diagnosis. When the cough fails to resolve with standard medications, referrals to other specialists including otolaryngologists are made. This is the first study to report the specific diagnosis and length of time it took to obtain a specific voice disorder diagnosis in patients with chronic cough.

STUDY DESIGN

Case Series METHODS: The charts of 105 patients referred to the Loma Linda Voice and Swallowing Center were reviewed. The first complaint of cough and/or hoarseness and the specific voice disorder diagnosis following otolaryngologic evaluation were identified. Voice disorders were divided into neurogenic or other/functional disorders and common comorbidities were identified. Statistical analysis between diagnostic groups, gender, and age were obtained.

RESULTS

The specific voice disorders in the cohort were identified. There was a high prevalence of neurogenic voice disorders (n = 85, 81%). There were significant relationships between chronic cough and the two most common neurogenic voice disorders, vocal fold paresis and vocal fold atrophy. The average length of time between complaint of hoarseness and the specific voice disorder diagnosis was 32.3 months. Most patients (86%) complained of voice problems after diagnosis of chronic cough. A significant association was found in prevalence of asthma (OR = 4.52, P = 0.02) and dyspnea (OR = 4.24, P = 0.02) in the cohort who presented first with voice complaints and later developed chronic cough.

CONCLUSIONS

There is a high incidence of neurogenic voice disorders accompanying patients with chronic cough. Understanding the relationship between chronic cough and hoarseness provides the clinician with specific diagnostic information in the treatment of both disorders.

Replenishment of myeloid-derived suppressor cells (MDSCs) overrides CR-mediated protection against tumor growth in a murine model of triple-negative breast cancer

Caloric restriction (CR) is the leading non-pharmacological intervention to delay induced and spontaneous tumors in pre-clinical models. These effects of CR are largely attributed to canonical inhibition of pro-growth pathways. However, our recent data suggest that CR impairs primary tumor growth and cancer progression in the murine 4T1 model of triple negative breast cancer (TNBC), at least in part, through reduced frequency of the myeloid-derived suppressor cells (MDSC). In the present study, we sought to determine whether injection of excess MDSCs could block regression in 4T1 tumor growth and metastatic spread in BALB/cJ female mice undergoing daily CR. Our findings show that MDSC injection impeded CR-mediated protection against tumor growth without increasing lung metastatic burden. Overall, these results reveal that CR can slow cancer progression by affecting immune suppressive cells.Impact statement: Inoculation of MDSCs from donor mice effectively impedes the ability of calorie restriction to protect against primary tumor growth without impacting lung metastatic burden in recipient animals.

Expiratory Muscle Strength Treatment for Refractory Chronic Cough: A Short-term Single Exercise Program

OBJECTIVES

Patients with chronic cough are some of the most challenging to treat. This preliminary study is the first to examine the effects of a single exercise muscle strength training program to reduce cough severity in patients who failed other treatments.

METHODS

A total of 19 females were included in this study, ranging from age 24 to 80. The maximum phonation time (MPT), laryngeal airway resistance (LAR), maximum inspiratory pressure (MIP) and maximum expiratory pressure (MEP), Voice Handicap Index-10, (VHI-10) and the Cough Severity Index (CSI) values were obtained pre- and post-treatment. ANOVA two-factor without replication was used to compare values pre- and post-treatment.

RESULTS

MIP (Mean of 62.00 to a mean of 78.53) and MEP (Mean of 90.00 to a mean of 112.16) showed significant increase post-treatment. In addition, LAR (Mean of 73.30 to a mean of 60.67) and CSI (Mean of 19.37 to a mean of 15.00) significantly decreased post-treatment. General changes in pre- and post-treatment values were identified with MPT (Mean of 14.89 to a mean of 16.17) and VHI-10 (Mean of 8.00 to a mean of 6.76). A follow-up questionnaire indicated that the majority of patients felt their cough was better after 4 weeks.

CONCLUSIONS

Muscle strength training provides a tool to aid in the control of cough for patients who are refractory to medical and other behavioral treatments. Improvement in cough may be associated with a reduction in subglottic pressure and increased air flow resulting in lower laryngeal airway resistance.

Recent Laryngology Fellowship Graduates: Where Are They Now?

OBJECTIVES

Over the past 30 years laryngology fellowships have grown in number and diversity. This study investigated the career trajectories of recent laryngology fellowship graduates with the purpose of informing residents considering fellowship.

STUDY DESIGN

Cross-sectional survey.

SETTING

Academic medical center.

METHODS

The directors of all 27 US laryngology fellowships that graduated/recruited fellows from 2010 to 2019 were contacted, and a list of former fellows was compiled. A short survey was administered in person or via email or phone. Additional data was gathered through internet searches.

RESULTS

One hundred eighty-three fellows were identified having completed American laryngology fellowships between 2010 and 2019 (100M:83F). Fifteen percent now practice internationally and 68% are in academic practice. A higher proportion of women than men enter laryngology fellowship after otolaryngology residency. One hundred twenty-nine fellows responded to our survey. Two-thirds of former fellows report current participation in laryngology research. Seventy-two percent of former fellows are still in their first job after fellowship and 53% believe they have their ideal practice. Women were more likely to enter academics than men after laryngology fellowship. Responders were overwhelmingly satisfied with their fellowship experience, with 95% saying they would choose to pursue fellowship training again.

CONCLUSIONS

Most former laryngology fellows enter academia, contribute to laryngology research, practice away from their training institution, and believe they have found their ideal practice. The results of this study may be useful to residents considering fellowship training, centers considering establishing laryngology fellowships, and practices recruiting fellowship graduates.

Esophageal stenosis in head and neck cancer patients: Imaging's accuracy to predict dilation response

OBJECTIVES

The primary goal of this study was to examine how well findings of cervical esophageal stenosis on modified barium swallow (MBS) and esophagram correlate with clinical improvement following dilation in patients with a history of head and neck (H&N) cancer.

METHODS

A retrospective review was performed at an academic hospital. The study population included H&N cancer patients with a history of neck dissection surgery who underwent esophageal dilation from 2010 to2018. Pre and postdilation swallowing function was assessed. The Functional Outcomes Swallowing Scale (FOSS) and Functional Oral Intake Scale (FOIS) were used as outcome measures.

RESULTS

The 95 patients were included. All patients had imaging prior to dilation. Post-dilation FOSS and FOIS scores were significantly improved (P < .001). In identifying the patients that would have improvement from dilation, esophagram and MBS had average sensitivities of 81% and 82%, respectively. The negative predictive value (ie, the ability of a normal esophagram or normal MBS to exclude patients that would not improve with dilation) was only 46% and 38%, respectively. When the specific finding of aspiration on MBS was considered, the positive predictive value (PPV) (ie, the ability of an MBS positive for aspiration to predict that a patient would benefit from dilation) was 87% (P = .03). When only the specific finding of stenosis on esophagram was considered, the PPV of improvement post-dilation was 58% (P = .97). The delay in time from imaging to dilation was significantly longer in those who had an unidentified stenosis (false negative) on imaging when compared to those who did not (46.8 ± 35.2 days vs 312.6 ± 244.1 days, P < .001).

CONCLUSION

In high risk patients for cervical esophageal stenosis, such as those with a history of H&N cancer and open neck surgery with or without radiation, MBS and esophagram appear to have mixed reliability as predictors of response to esophageal dilation. In these patients, a "negative" result on MBS and esophagram may not be diagnostically accurate enough to exclude patients from consideration of dilation.

LEVEL OF EVIDENCE

IIb.

Effects of Cough Suppression Therapy on Voice Disorder Severity

OBJECTIVES//HYPOTHESIS

To determine changes in voice severity when treating chronic cough refractory to medical treatment with cough suppression therapy (CST) in patients with chronic cough and voice complaints. Chronic cough has been reported to be refractory to medical treatment and frequently co-occurs with voice disorders. The possible effects of CST on self-assessed changes in chronic cough and voice disorders have not been demonstrated.

STUDY DESIGN

Retrospective analysis of the effects of cough suppression therapy (CST) on self-assessed changes in chronic cough and voice disorder severity in patients with both chronic cough and voice disorders.

METHODS

Forty-three adult patients with the primary complaint of chronic refractory cough underwent pre- and post-treatment diagnostic examinations, completed pre- and post-treatment Voice Handicap Index-10 (VHI-10) and Cough Severity Index assessments, and were treated by a licensed speech-language pathologist using CST. Twenty-seven subjects were assigned to the cough (C) group and 16 to the cough-voice (CV) group based on the severity of their VHI-10 scores.

RESULTS

Post-test analysis showed significant improvement in cough severity for both groups and significant improvement in voice severity for the CV group. The VHI-10 scores for the C group did not change significantly. The median number of treatment sessions was 3, with a range of 1-13 sessions. Correlation between changes in severity and number of treatment sessions was not found to be significant at the tested level.

CONCLUSIONS

CST represents a unifying approach for treatment of patients with CRC and comorbid voice disorders. CST offered cross-over effects to the voice when subjects were treated for their primary complaint of chronic cough. This treatment of the primary complaint improves function in systems that share a common pathway.

LEVEL OF EVIDENCE

IV Laryngoscope, 2021.

Assessment of Clinical and Social Characteristics That Distinguish Presbylaryngis From Pathologic Presbyphonia in Elderly Individuals

Importance

An aging population experiences an increase in age-related problems, such as presbyphonia. The causes of pathologic presbyphonia are incompletely understood.

Objective

To determine what distinguishes pathologic presbyphonia from presbylaryngis.

Design, Setting, and Participants

This was a cohort study at an outpatient otolaryngology subspecialty clinic of a tertiary academic referral center. Participants were consecutive consenting adults older than 74 years without laryngeal pathologic abnormalities who visited the clinic as participants or companions. Patient questionnaires, otolaryngologic, video stroboscopic, and voice examinations were compiled. Patients were divided into groups based on whether they endorsed a voice complaint. Three blinded authors graded stroboscopic examinations for findings consistent with presbylaryngis (vocal fold bowing, vocal process prominence, glottic insufficiency).

Main Outcomes and Measures

Voice Handicap Index-10, Reflux Symptom Index, Cough Severity Index, Dyspnea Index, Singing Voice Handicap Index-10 , Eating Assessment Tool -10, Voice-Related Quality of Life (VRQOL), and Short-Form Health Survey; face-sheet addressing social situation, work, marital status, education, voice use, transportation; acoustic and aerodynamic measures; and a full otolaryngologic examination, including videostroboscopic imaging.

Results

A total of 31 participants with dysphonia (21 were female; their mean age was 83 years [range, 75-97 years]) and 26 control participants (16 were female; their mean age was 81 years [range, 75-103 years]) completed the study. Presbylaryngis was visible in 27 patients with dysphonia (87%) and 22 controls (85%). VHI-10 and VRQOL scores were worse in patients with pathologic presbyphonia (median [range] VHI-10 scores, 15 (0-40) vs 0 (0-16) and median VRQOL score, 19 [0-43] vs 10 [10-23]). All other survey results were indistinguishable, and no social differences were elucidated. Acoustic measures revealed that both groups averaged lower than normal speaking fundamental frequency (mean [SD], 150.01 [36.23] vs 150.85 [38.00]). Jitter was 3.44% (95% CI, 2.46%-4.61%) for pathologic presbyphonia and 1.74% (95% CI, 1.35%-2.14%) for controls (d = 0.75). Shimmer means (95% CI) were 7.8 2 (6.08-10.06) for the pathologic presbyphonia group and 4.84 (3.94-5.72) for controls (d = 0.69). Aerodynamic measures revealed an odds ratio of 3.03 (95% CI, 0.83-11.04) for patients with a maximum phonation time of less than 12 seconds who had complaints about dysphonia.

Conclusions and Relevance

Presbylaryngis is present in most ambulatory people older than 74 years. Some will endorse pathologic presbyphonia that has a negative effect on their voice and quality of life. Pathologic presbyphonia seems to be influenced by respiratory capacity and sex. Further study is required to isolate other social, physiologic, and general health characteristics that contribute to pathologic presbyphonia.

Gossypiboma: a ghastly find

A gossypiboma is a mass within a patient's body comprising a cotton matrix surrounded by a foreign body granuloma. We describe an unusual presentation of a gossypiboma presenting in a 32-year-old man with acute epigastric pain and haematemesis. His surgical history revealed an emergency laparotomy following a road traffic accident 16 years ago. Initial gastroscopy showed extrinsic stomach compression. An abdominal ultrasound scan followed by a CT scan evidenced a large, well-defined, predominantly cystic mass with some solid areas occupying the left hypochondrium. Conservative management with insertion of a percutaneous drain proved to be inefficient. A laparotomy was performed; intraoperatively, the cyst was found to be ruptured and within it, a large surgical gauze was found. This was removed but required a distal pancreatectomy and gastrectomy for complete excision. He was discharged on day 74 of admission with outpatient follow-up.

Esophagram findings in cervical esophageal stenosis: A case-controlled quantitative analysis

OBJECTIVE

Cervical esophageal stenosis is often diagnosed with a qualitative evaluation of a barium esophagram. Although the esophagram is frequently the initial screening exam for dysphagia, a clear objective standard for stenosis has not been defined. In this study, we measured esophagram diameters in order to establish a quantitative standard for defining cervical esophageal stenosis that requires surgical intervention.

STUDY DESIGN

Single institution case-control study.

METHODS

Patients with clinically significant cervical esophageal stenosis defined by moderate symptoms of dysphagia (Functional Outcome Swallowing Scale > 2 and Functional Oral Intake Scale < 6) persisting for 6 months and responding to dilation treatment were matched with age, sex, and height controls. Both qualitative and quantitative barium esophagram measurements for the upper, mid-, and lower vertebral bodies of C5 through T1 were analyzed in lateral, oblique, and anterior-posterior views.

RESULTS

Stenotic patients versus nonstenotic controls showed no significant differences in age, sex, height, body mass index, or ethnicity. Stenosis was most commonly at the sixth cervical vertebra (C 6) lower border and C7 upper border. The mean intraesophageal minimum/maximum ratios of controls and stenotic groups in the lateral view were 0.63 ± 0.08 and 0.36 ± 0.12, respectively (P < 0.0001). Receiver operating characteristic analysis of the minimum/maximum ratios, with a <0.50 ratio delineating stenosis, demonstrated that lateral view measurements had the best diagnostic ability. The sensitivity of the radiologists' qualitative interpretation was 56%. With application of lateral intraesophageal minimum/maximum ratios, we observed improved sensitivity to 94% of the esophagram, detecting clinically significant stenosis.

CONCLUSION

Applying quantitative determinants in esophagram analysis may improve the sensitivity of detecting cervical esophageal stenosis in dysphagic patients who may benefit from surgical therapy.

LEVEL OF EVIDENCE

IIIb. Laryngoscope, 128:2022-2028, 2018.

Treating laryngopharyngeal reflux: Evaluation of an anti-reflux program with comparison to medications

OBJECTIVE

To determine if an anti-reflux induction program relieves laryngopharyngeal reflux (LPR) symptoms more effectively than medication and behavioral changes alone.

STUDY DESIGN

Retrospective study.

SETTING

Tertiary care academic center.

SUBJECTS AND METHODS

A database was populated with patients treated for LPR. Patients were included in the study group if they completed a two-week anti-reflux program (diet, alkaline water, medications, behavioral modifications). Patients were included in the control group if they completed anti-reflux medications and behavioral modifications only. Patients completed the voice handicap index (VHI), reflux symptom index (RSI), cough severity index (CSI), dyspnea index (DI) and eating assessment tool (EAT-10) surveys and underwent laryngoscopy for examination and reflux finding score (RFS) quantification.

RESULTS

Of 105 study group patients, 96 (91%) reported subjective improvement in their LPR symptoms after an average 32-day first follow-up and their RSI and CSI scores improved significantly. No significant differences were found in VHI, DI, or EAT-10 scores. Fifteen study patients who had previously failed adequate high-dose medication trials reported improvement and their CSI and EAT-10 scores improved significantly. Ninety-five percent of patients with a chief complaint of cough reported improvement and their CSI scores improved significantly from 12.3 to 8.2. Among 81 controls, only 39 (48%) patients reported improvement after an average 62-day first follow-up. Their RSI scores did not significantly change.

CONCLUSION

The anti-reflux program yielded rapid and substantial results for a large cohort of patients with LPR. It compared favorably with medication and behavioral modification alone. It was effective in improving cough and treating patients who had previously failed medications alone.

Microbiome diversity in the sputum of patients with pulmonary tuberculosis

TB is a worldwide pandemic. India has the highest burden of TB, with WHO statistics for 2013 giving an estimated incidence figure of 2.1 million cases for India out of a global incidence of 9 million. Microbiota have been shown to be associated with many disease conditions; however, only few studies have been reported for microbiota associated with TB infection. For the first time, we characterized the composition of microbiota of TB patients of India, using high-throughput 16S rRNA gene sequencing and compared it with healthy controls. Phylum-level analysis showed that the relative abundance of Firmicutes and Actinobacteria was significantly higher in TB samples and Neisseria and Veillonella were two dominant genera after Streptococcus. In our study, significantly different core genera in TB and normal population were found as compared with the reported studies. Also, the presence of diverse opportunistic pathogenic microbiota in TB patients increases the complexity and diversity of sputum microbiota. Characterization of the sputum microbiome is likely to provide important pathogenic insights into pulmonary tuberculosis.

Medicolegal Aspects of Iatrogenic Dysphonia and Recurrent Laryngeal Nerve Injury

Objective

To examine aspects of litigation involving iatrogenic dysphonia and injury to the recurrent laryngeal nerve in the adult population.

Study Design

Legal database review.

Setting

Medicolegal judicial system.

Subjects and Methods

Jury verdicts and settlement reports listing voice impairment or recurrent laryngeal nerve dysfunction as a primary injury in adult patients were identified in the Westlaw Database. Reports were examined for plaintiff demographics, defendant specialty, procedure performed, rates of settlements and verdicts, monetary awards, primary plaintiff symptoms, and common allegations.

Results

A total of 123 jury verdict and settlement reports were identified. General surgeons (24%), otolaryngologists (20%), and anesthesiologists (18%) were involved in the majority of cases. The procedure causing the alleged injury was primarily thyroidectomy (34%), followed by intubation (18%) and spinal instrumentation (10%). The majority of cases (70%) were decided in favor of the defendant. Where monetary awards were recorded, settlements and jury verdicts in favor of the plaintiff ranged between $4250 and $3,000,000, with a mean of $788,713. In addition to voice disturbances, complaints of dyspnea and dysphagia were commonly listed alleged injuries. The only factors associated with plaintiff verdicts were general surgery specialty (odds ratio, 6.3; 95% confidence interval, 1.7-23.2) and claims of loss of consortium (odds ratio, 8.5; 95% confidence interval, 1.2-60.7).

Conclusion

Dysphonia is a common complication in a number of procedures across multiple specialties. Although the majority of cases are decided in favor or the defendant, payments awarded can be considerable. Awareness of factors involved in these medical malpractice cases can help limit physician liability.

Prospective investigation of nimodipine for acute vocal fold paralysis

INTRODUCTION

Nimodipine has been shown to be beneficial for recovery from acute vocal fold paralysis (AVFP) in an animal model.

METHODS

prospective, open-label trial of patients with AVFP was performed using nimodipine. Consecutive patients were evaluated and offered nimodipine therapy.

RESULTS

Fifty-three patients were considered for treatment with nimodipine. Thirteen did not qualify for inclusion, 5 were lost to follow-up, and 7 had side effects requiring cessation of treatment. Thus 28 patients (30 paralyzed vocal folds) were analyzed. Eighteen of the paralyzed vocal folds experienced recovery of purposeful motion (60%). Historical controls and laryngeal electromyography meta-analysis suggest no more than a 20% recovery rate from AVFP.

CONCLUSIONS

This open label study using nimodipine for treatment of AVFP demonstrates tripling of the recovery rate of vocal fold motion compared with historical controls. Further study in a randomized, controlled manner is warranted.

The effects of decorin and HGF-primed vocal fold fibroblasts in vitro and ex vivo in a porcine model of vocal fold scarring

OBJECTIVES

Vocal fold injury can be irreversible, leading to vocal fold scarring, with permanent functional effects and no optimal treatment. A porcine model of vocal fold scarring was used to test effects of decorin and primed vocal fold fibroblasts in vitro using a cell migration assay and immunoblotting, and by using functional measurements of porcine larynges and excised porcine vocal folds.

METHODS

In vitro: primary pig vocal fold fibroblasts (PVFFs) were subjected to cell migration assays (scratch) and treated with decorin 20 μg/mL, hepatocyte growth factor (HGF) 200 ng/mL, epidermal growth factor (EGF) 1 nM, or transforming growth factor-β1 10 ng/mL. Cells also underwent decorin dose response testing. Scratch assays were analyzed in MetaMorph® Imaging; cell lysates were processed for MMP-8 and type I collagen content. Eleven pigs underwent unilateral vocal fold stripping procedures. At day 3 postoperatively, subjects underwent superficial injection into the affected vocal fold either with decorin 20 μg/mL or 1 × 10(6) HGF-primed fibroblasts. Larynges were harvested and either used for ex vivo laryngeal testing or for rheological testing.

RESULTS

Scratch assay indicated significantly reduced cell migration in PVFFs treated with decorin or HGF. MMP-8 production was increased (P <0.01) and collagen was decreased in cells treated with decorin at increasing doses. Viscoelastic measurements suggested somewhat increased stiffness for decorin treated samples. Ex vivo aerodynamic testing suggested improved vocal efficiency scores in decorin-treated larynges.

CONCLUSIONS

Decorin has a noticeable effect on PVFF migration in vitro and appears to increase vocal fold stiffness but either does not change or slightly increases vocal efficiency.

Lack of CXC chemokine receptor 3 signaling leads to hypertrophic and hypercellular scarring

CXC chemokine receptor 3 (CXCR3) signaling promotes keratinocyte migration while terminating fibroblast and endothelial cell immigration into wounds; this signaling also directs epidermal and matrix maturation. Herein, we investigated the long-term effects of failure to activate the "stop-healing" CXCR3 axis. Full-thickness excisional wounds were created on CXCR3 knockout((-/-)) or wild-type mice and examined at up to 180 days after wounding. Grossly, the CXCR3(-/-) mice presented a thick keratinized scar compared with the wild-type mice in which the scar was scarcely noticeable; histological examination revealed thickening of both the epidermis and dermis. The dermis was disorganized with thick and long collagen fibrils and contained excessive collagen content in comparison with the wild-type mice. Interestingly, the CXCR3(-/-) wounds presented lower tensile/burst strength, which correlates with decreased alignment of collagen fibers, similar to published findings of human scars. Persistent Extracellular matrix turnover and immaturity was shown by the elevated expression of proteins of the immature matrix as well as expression of matrix metallopeptidase-9 MMP-9. Interestingly, the scars in the CXCR3(-/-) mice presented evidence of de novo development of a sterile inflammatory response only months after wounding; earlier periods showed resolution of the initial inflammatory stage. These in vivo studies establish that the absence of CXCR3(-/-) signaling network results in hypertrophic and hypercellular scarring characterized by on-going wound regeneration, cellular proliferation, and scars in which immature matrix components are undergoing increased turnover resulting in a chronic inflammatory process.

Effects of transforming growth factor-beta1 on human vocal fold fibroblasts

OBJECTIVES

We studied the effect of transforming growth factor (TGF)-beta on immortalized human vocal fold fibroblasts.

METHODS

Normal human vocal fold fibroblasts were subjected to sequential lentiviral transduction with genes for human telomerase (hTERT) and SV40 large T antigen in order to produce an "immortalized" cell line of normal phenotype. After confirmation of vocal fold fibroblast transfection, these cells, referred to as HVOX, were treated with various concentrations of exogenous TGF-beta1 and assayed for collagen secretion, migration, and proliferation. In addition, components of the TGF-beta signaling pathway were examined in this cell line.

RESULTS

TGF-beta stimulated collagen secretion and migration without altering proliferation of HVOX. HVOX constitutively expressed type I and II TGF-beta receptors, as well as messenger RNA for the Smad signaling proteins and for all TGF-beta isoforms. Exogenous TGF-beta1 induced temporally dependent alterations in Smad2 and Smad3 gene expression. TGF-beta increased Smad7 expression at both 4 and 24 hours. Prolonged exposure to TGF-beta decreased TGF-beta1 gene expression.

CONCLUSIONS

Insight into the underlying pathophysiology of vocal fold fibrosis is likely to yield improved therapeutic strategies to mitigate vocal fold scarring. Our data suggest that TGF-beta signaling may be both paracrine and autocrine in this vocal fold fibroblast cell line, and we therefore propose that TGF-beta may be a reasonable target for therapies to prevent and/or treat vocal fold fibrosis, given its putative role in both acute and chronic vocal fold injury, as well as its effects on vocal fold fibroblasts.

The effect of multifunctional polymer-based gels on wound healing in full thickness bacteria-contaminated mouse skin wound models

We determined whether a two-part space-conforming polyethylene glycol/dopa polymer-based gel promoted healing of contaminated wounds in mice. This silver-catalysed gel was previously developed to be broadly microbiocidal in vitro while being biocompatible with human wound cell functioning. Full-thickness wounds were created on the backs of mice. The wounds were inoculated with 10(4) CFU of each of four common skin wound contaminants, Staphylococcus aureus, Pseudomonas aeruginosa, Acinetobacter baumanii and Clostridium perfringens. The wounds were then treated with our multifunctional polymer-based gel, the commercially available NewSkin product, or left to heal untreated. The untreated wounds were overtly infected, and presented detectable bacterial loads over the entire 21-day healing period, while the gel and NewSkin groups presented significantly smaller rises in bacterial levels and were cleared of detectable colonies by the third week, with the gel group clearing the bacteria earlier. While all three groups healed their wounds, the polymer-based gel-treated group demonstrated significantly earlier re-epithelialization and dermal maturation (P<0.05). This was reflected in a quick regain of tensile strength. This accelerated dermal maturation and regain in strength was noted in mice treated with the polymer-based gel when compared to wound treated with the commercially available Aquacel-Ag dressing (P<0.05). What distinguishes the polymer-based gel from these other products is that it is incorporated within the healing wound. These preclinical studies show that the anti-microbial polymer gel not only supports but also accelerates healing of bacterially contaminated wounds.

Primed fibroblasts and exogenous decorin: potential treatments for subacute vocal fold scar

OBJECTIVE

To investigate hepatocyte growth factor (HGF) primed fibroblasts and decorin application on skin and vocal fold fibroblasts in vitro and in vivo in rabbit vocal fold scar model.

STUDY DESIGN AND SETTING

Vocal fold and skin fibroblasts underwent five in vitro treatment conditions: control, epidermal growth factor, HGF, both decorin and HGF, and decorin alone. Hyaluronic acid and collagen enzyme-linked immunosorbent assays were performed. In vivo, 12 rabbits underwent unilateral vocal fold stripping. Injured vocal folds were then injected with skin fibroblasts, HGF, HGF-primed fibroblasts and decorin, or decorin. Outcomes included histologic and lamina propria height analyses.

RESULTS

In vitro, HGF increased hyaluronic acid synthesis in vocal fold fibroblasts (P<0.001). HGF and decorin treatment diminished collagen secretion (P<0.01). In vivo, histologic findings indicated minimal difference in collagen amount between treatment groups.

CONCLUSION

HGF and decorin together may decrease collagen production by skin and vocal fold fibroblasts. Fibroblast transplantation into scarred vocal folds has equivocal benefit.

Operating Room Versus Office-Based Injection Laryngoplasty: A Comparative Analysis of Reimbursement

BACKGROUND

Injection laryngoplasty (IL) continues to evolve as new indications, techniques, approaches, and injection materials are developed. Although historically performed under local or general anesthesia in the operating room suite, IL is now increasingly being performed in an office-based setting. This report presents the results of a reimbursement analysis comparing office-based versus operative IL.

OBJECTIVE

The objective of this study was to compare the reimbursement of office-based injection laryngoplasty with the reimbursement of performing the same procedure in the operating room.

DESIGN

The authors conducted reimbursement and outcome analysis through retrospective office chart and hospital record review.

METHODS

A retrospective review was performed of the hospital records of patients having undergone injection laryngoplasty at the University of Pittsburgh Voice Center from July 1998 through March 2005. Group I included patients who underwent IL in the operating room, whereas group II included those who had office-based IL. A reimbursement analysis for both groups was then performed comparing surgeon fees, anesthesia, and hospital charges and reimbursement. The clinical efficacy of IL performed in either office versus operating room settings was measured by comparing the pre- and postintervention Voice Handicap Index-10 scores for all patients. A predictive model of potential cost savings is developed based on the results of the analysis.

RESULTS

Average reimbursement was 2,505 dollars for group I (n = 108) and 496 dollars for group II (n = 50). This reimbursement differential was preserved across the various insurance types examined. There was no significant difference in Voice Handicap Index-10 change after surgery between group I and II.

CONCLUSIONS

Office-based IL is both clinically and financially effective, providing patients with a convenient and flexible alternative to operating room-based intervention for glottal insufficiency.

Office-Based Arytenoid Palpation for Diagnosis of Disorders of Bilateral Vocal Fold Immobility

Bilateral vocal fold immobility is an uncommon but serious condition with many causes. Accordingly, accurate diagnosis is essential in order to treat patients promptly and avoid long-term sequelae. Historically, diagnosis has been performed in the operating room with the patient under general anesthesia. We present the case of a patient who was diagnosed with bilateral vocal fold immobility by in-office arytenoid palpation that required only topical anesthesia of the larynx. The patient subsequently underwent appropriate treatment. In our opinion, office-based arytenoid palpation is a simple, safe, and accurate procedure for diagnosing bilateral vocal fold immobility.

Office-based arytenoid palpation for diagnosis of disorders of bilateral vocal fold immobility

Bilateral vocal fold immobility is an uncommon but serious condition with many causes. Accordingly, accurate diagnosis is essential in order to treat patients promptly and avoid long-term sequelae. Historically, diagnosis has been performed in the operating room with the patient under general anesthesia. We present the case of a patient who was diagnosed with bilateral vocal fold immobility by in-office arytenoid palpation that required only topical anesthesia of the larynx. The patient subsequently underwent appropriate treatment. In our opinion, office-based arytenoid palpation is a simple, safe, and accurate procedure for diagnosing bilateral vocal fold immobility.

Hearing Loss as the Initial Presentation of Creutzfeldt-Jakob Disease

Creutzfeldt-Jakob disease is a rare type of spongiform encephalopathy. Affected patients present with constitutional symptoms, which progress to severe mental deterioration and movement disorders. Dizziness is the most common early otologic symptom. Few reports in the literature describe patients with Creutzfeldt-Jakob disease who present with sudden-onset hearing loss as their primary symptom for seeking treatment. This paper discusses one such patient and reviews the clinical presentation, treatment options, and relevant literature.

Hearing loss as the initial presentation of Creutzfeldt-Jakob disease

Creutzfeldt-Jakob disease is a rare type of spongiform encephalopathy. Affected patients present with constitutional symptoms, which progress to severe mental deterioration and movement disorders. Dizziness is the most common early otologic symptom. Few reports in the literature describe patients with Creutzfeldt-Jakob disease who present with sudden-onset hearing loss as their primary symptom for seeking treatment. This paper discusses one such patient and reviews the clinical presentation, treatment options, and relevant literature.

Current practice patterns in tonsillectomy and perioperative care

OBJECTIVES

Tonsillectomy is one of the most commonly performed otolaryngologic procedures in the United States. Many options and controversies exist regarding techniques and peri-operative management. The purpose of the study was to examine current practice patterns among otolaryngologists regarding tonsillectomy.

METHODS

A 13 question survey regarding tonsillectomy techniques and peri-operative management was mailed to 10% of randomly selected board certified otolaryngologists of the AAO-HNS in the spring of 2002. Four hundred and eighteen anonymously completed questionnaires were returned, for a response rate of 58.5%. Statistical analysis of survey data was performed by means of cross tabulation and Pearson Chi-Square Calculation.

RESULTS

Monopolar electrocautery was the most common technique used among those surveyed (53.5%). There was a significant correlation between choice of monopolar electrocautery and the cited reason for choice of technique being decreased blood loss (P < 0.001). There was no relationship between pediatric fellowship training and choice of technique. 97.7% routinely admitted sleep apnea patients for post-operative observation. There was no significant correlation between practice setting (tertiary versus community) and type of post-operative monitoring for sleep apnea patients, with patients most commonly admitted to an intermediate care setting.

CONCLUSION

In our survey, the most common surgical technique for tonsillectomy was monopolar electrocautery, chosen for the reason of decreased blood loss.

Self-inflicted vocal cord paralysis in patients with vagus nerve stimulators. Report of two cases

Vagus nerve stimulation for treatment of epilepsy is considered safe; reports of severe complications are rare. The authors report on two developmentally disabled patients who experienced vocal cord paralysis weeks after placement of a vagus nerve stimulator. In both cases, traction injury to the vagus nerve resulting in vocal cord paralysis was caused by rotation of the pulse generator at the subclavicular pocket by the patient. Traumatic vagus nerve injury caused by patients tampering with their device has never been reported and may be analogous to a similar phenomenon reported for cardiac pacemakers in the literature. As the use of vagus nerve stimulation becomes widespread it is important to consider the potential for this adverse event.

Post-tonsillectomy bleeding: a meta-analysis

OBJECTIVE/HYPOTHESIS

To reconcile conflicting reports and opinions of the value of preoperative coagulation studies for patients undergoing tonsillectomy.

STUDY DESIGN

Meta-analysis: Articles were identified by MEDLINE search, references from review articles, textbook chapter, and retrieved reports. Independent observers selected prospective trials of patients undergoing tonsillectomy or adenoidectomy and tonsillectomy. Retrospective studies meeting other inclusion and exclusion criteria were included for sensitivity analyses of results.

METHODS

Data were abstracted from studies for an end point of bleeding with normal and abnormal coagulation tests. Four prospective studies met all inclusion and exclusion criteria. These four studies were used in the data synthesis. An additional eight retrospective studies met all other criteria and were used in the sensitivity analysis.

RESULTS

Pooled analysis of 3384 patients revealed a rate of 3.3% (95% confidence interval [CI], 2.5%-4.1%) for post-tonsillectomy bleeding in patients with normal coagulation studies. A rate of 8.7% (95% CI, 1.5%-15.9%) was obtained for bleeding in patients with abnormal coagulation studies. No significant rate difference in post-tonsillectomy bleeding was demonstrated.

CONCLUSION

There is no difference in the rate of post-tonsillectomy bleeding in patients with abnormal coagulation studies as compared with patients with normal coagulation studies obtained preoperatively.

The Hsp90 family of proteins in Arabidopsis thaliana

The 90-kDa heat shock protein (Hsp90) is an essential molecular chaperone in eukaryotic cells, with key roles in the folding and activation of proteins involved in signal transduction and control of the cell cycle. A search for Hsp90 sequences in the Arabidopsis thaliana genome revealed that this family includes 7 members. The AtHsp90-1 through AtHsp90-4 proteins constitute the cytoplasmic subfamily, whereas the AtHsp90-5, AtHsp90-6, and AtHsp90-7 proteins are predicted to be within the plastidial, mitochondrial, and endoplasmic reticulum compartments, respectively. The deduced amino acid sequences of each of the cytoplasmic proteins contains the highly conserved C-terminal pentapeptide MEEVD. All of the AtHsp90 sequences include a conserved adenosine triphosphate-binding domain, whereas only the cytoplasmic and endoplasmic reticulum-resident sequences include an adjacent charged linker domain that is common in mammalian and yeast sequences. The occurrence of multiple AtHsp90 proteins in the cytoplasm and of family members in other subcellular compartments suggests a range of specific functions and target polypeptides.

Hsp90-binding immunophilins in plants: the protein movers

Studies of cytoplasmic-nuclear trafficking of the glucocorticoid receptor in mammalian cells suggest that the hsp90/hsp70-based chaperone system and the hsp90-binding immunophilin FKBP52 are involved in targeted movement of the receptor along microtubule tracts. Over the past few years, plant cells have been found to possess a similar multiprotein chaperone machinery. Plant cells also contain high molecular weight FKBPs that bind to plant hsp90 via a conserved protein interaction involving tetratricopeptide repeat domains. The hsp90/hsp70-based machinery and the plant FKBPs might be used to target the trafficking of signalling proteins in plants.

A glucosinolate mutant of Arabidopsis is thermosensitive and defective in cytosolic Hsp90 expression after heat stress

The TU8 mutant of Arabidopsis previously described to be deficient in glucosinolate metabolism and pathogen-induced auxin accumulation was found to be remarkably less tolerant upon exposure to elevated temperatures than wild-type plants. Although moderately increased temperature only affected shoot growth, exposure to severe heat stress led to a dramatic decay of mutant plants. By contrast, wild-type seedlings showed little or no damage under the same conditions. Analysis of different heat stress proteins (Hsps) in TU8 seedlings revealed that only expression of cytoplasmic Hsp90 was affected in these plants. Although Hsp90 was present under control conditions, its level declined in mutant plants at elevated temperatures. Northern-blot analysis indicated that the decrease in Hsp90 protein was accompanied with a reduction of hsp90 transcript levels. Transient expression of Hsp90 in mutant protoplasts increased their survival rate at higher temperatures to near equivalent that of wild-type protoplasts. These data suggest that the reduced level of Hsp90 in TU8 mutants may be the primary cause for the observed reduction in thermostability.

Pediatric hemorrhagic thyroid nodule: a case report

Hemorrhagic thyroid nodules are rare in the pediatric age group. They present as rapidly enlarging neck masses. Diagnostic modalities available are laboratory evaluation, ultrasound, radionuclide imaging, and fine needle aspiration. Depending on the pattern of growth of the lesion, one may observe or proceed with surgery. A rapidly enlarging thyroid mass raises the suspicion of malignancy, and hemorrhagic nodules, though rare, must be considered in the differential diagnosis.

Treatment with 24-epibrassinolide, a brassinosteroid, increases the basic thermotolerance of Brassica napus and tomato seedlings

Brassinosteroids are plant growth-promoting compounds that exhibit structural similarities to animal steroid hormones. Recent studies have indicated that brassinosteroids are essential for proper plant development. In addition to a role in development, several lines of evidence suggest that brassinosteroids exert anti-stress effects on plants. However, the mechanism by which they modulate plant stress responses is not understood. We show here that Brassica napus and tomato seedlings grown in the presence of 24-epibrassinolide (EBR) are significantly more tolerant to a lethal heat treatment than are control seedlings grown in the absence of the compound. Since a preconditioning treatment of seedlings was not required to observe this effect, we conclude that EBR treatment increases the basic thermotolerance of seedlings. An analysis of heat shock proteins (HSPs) in B. napus seedlings by western blot analysis indicated that the HSPs did not preferentially accumulate in EBR-treated seedlings at the control temperature. However, after heat stress, HSP accumulation was higher in EBR-treated than in untreated seedlings. The results of the present study provide the first direct evidence for EBR-induced expression of HSPs. The higher accumulation of HSPs in EBR-treated seedlings raises the possibility that HSPs contribute, at least in part, to thermotolerance in EBR-treated seedlings. A search for factors other than HSPs, which may directly or indirectly contribute to brassinosteroid-mediated increase in thermotolerance, is underway.

Mass spectral study of substituted allyl aryl and allyl alkyl selenides and some analogous sulfides

The electron impact (EI) mass spectra of allyl aryl selenides showed abundant molecular ions and many fragment ions containing the selenium atom. alpha-Cleavage is the dominant process in the fragmentation of selenides, and cleavage product ions are characteristic of the substituents. In the case of 3-methyl allyl and related aryl selenides, characteristic delta-hydrogen migration to the selenium atom is observed. A McLafferty-type rearrangement is found in benzyl allyl selenides and substituted alkyl allyl selenides. The charge on the rearrangement products preferably remains on the fragments containing the phenyl group. The [M - SeH](+), [M - CH(3)](+) and [M - C(2)H(4)](+) ions are found only in the EI mass spectrum of allyl phenyl selenide, and are attributed to a Claisen rearrangement in the source of the mass spectrometer. All structurally informative fragmentation processes are supported by collision induced dissociation spectra of molecular ions. The fragmentation patterns found in methane chemical ionization (CI) spectra of the selenides were significantly different from those observed in EI. The EI and CI mass spectra of analogous sulfides showed similar behaviour to that observed in the corresponding selenides. Copyright 1999 John Wiley & Sons, Ltd.

High-molecular-weight FK506-binding proteins are components of heat-shock protein 90 heterocomplexes in wheat germ lysate

In animal cell lysates the multiprotein heat-shock protein 90 (hsp90)-based chaperone complexes consist of hsp70, hsp40, and p60. These complexes act to convert steroid hormone receptors to their steroid-binding state by assembling them into heterocomplexes with hsp90, p23, and one of several immunophilins. Wheat germ lysate also contains a hsp90-based chaperone system that can assemble the glucocorticoid receptor into a functional heterocomplex with hsp90. However, only two components of the heterocomplex-assembly system, hsp90 and hsp70, have thus far been identified. Recently, purified mammalian p23 preadsorbed with JJ3 antibody-protein A-Sepharose pellets was used to isolate a mammalian p23-wheat hsp90 heterocomplex from wheat germ lysate (J.K. Owens-Grillo, L.F. Stancato, K. Hoffmann, W.B. Pratt, and P. Krishna [1996] Biochemistry 35: 15249-15255). This heterocomplex was found to contain an immunophilin(s) of the FK506-binding class, as judged by binding of the radiolabeled immunosuppressant drug [3H]FK506 to the immune pellets in a specific manner. In the present study we identified the immunophilin components of this heterocomplex as FKBP73 and FKBP77, the two recently described high-molecular-weight FKBPs of wheat. In addition, we present evidence that the two FKBPs bind hsp90 via tetratricopeptide repeat domains. Our results demonstrate that binding of immunophilins to hsp90 via tetratricopeptide repeat domains is a conserved protein interaction in plants. Conservation of this protein-to-protein interaction in both plant and animal cells suggests that it is important for the biological action of the high-molecular-weight immunophilins.

Brassica napus hsp90 can autophosphorylate and phosphorylate other protein substrates

A Brassica napus cDNA encoding the 90 kDa heat shock protein, hsp90, was modified to add 6 histidines at the C-terminus and expressed in insect cells to prepare a recombinant histidine-tagged hsp90. The recombinant protein was purified over Ni2+-NTA agarose columns and its identity was confirmed by Western blotting, using a plant hsp90-specific antiserum. Incubation of purified hsp90 with [gamma-32P] ATP in the presence of Mn2+ resulted in its autophosphorylation on serine residues. The purified hsp90 could also phosphorylate other protein substrates such as histones and casein in the presence of Mn2+. Analysis of phosphorylated casein revealed that serine residues are phosphorylated by hsp90. This is the first demonstration that a cytosolic hsp90 homolog can phosphorylate other protein substrates.