Eustachian tube dysfunction symptoms after endonasal skull base surgery

KEY POINTS

ETD symptoms are present in 16% patients with underlying skull base pathology. Preoperative ETD symptoms improve following surgical treatment of skull base pathology. ETD symptoms may worsen in patients with central, posterior, or malignant skull base pathology.

Surgical Correction of Nasal Obstruction and Its Effect on Eustachian Tube Dysfunction Symptoms

OBJECTIVES

To investigate how eustachian tube dysfunction symptoms change following surgical treatment of nonsinusitis-related nasal obstruction.

STUDY DESIGN

Retrospective chart review.

SETTING

Single academic center.

METHODS

We assessed patients who underwent septoplasty, turbinate reduction, or both for nasal obstruction. Chronic sinusitis patients were excluded. Eustachian tube dysfunction (ETD) symptoms were studied using the Eustachian Tube Dysfunction Questionnaire (ETDQ-7), collected preoperatively and postoperatively (1 week, 1 month, 3 months, 6 months postop). Patients with preoperative ETDQ-7 > 14.5 were considered to have clinically significant symptoms. Sinonasal outcomes test scores were also assessed. Pre- and postoperative ETDQ-7 scores were compared using t test. Multivariate linear regression analysis identified factors associated with ETDQ-7 change.

RESULTS

We analyzed 259 patients. Preoperatively, 37.5% of patients with nasal obstruction had clinically significant ETD symptoms. These patients exhibited significant improvement in ETDQ-7 at all postoperative timepoints from 23.3 ± 7.6 at baseline to 19.1 ± 9.1 at 1 week, 16.5 ± 8.0 at 1 month, 16.2 ± 7.8 at 3 months, and 16.7 ± 10.4 at 6 months (all P < .01). In patients without baseline ETD symptoms, (baseline ETDQ-7: 9.1 ± 2.3) ETDQ-7 scores did not change significantly at postoperative timepoints, except for an acute worsening at 1 week postoperatively (10.7 ± 5.1, P < .001). Regression analysis showed that higher preoperative ETDQ-7 score (β = -0.84, 95% confidence interval [CI]: -1.10 to -0.59) and postoperative antihistamine spray usage (β = -8.70, 95% CI: -14.20 to -3.20) were associated with ETDQ-7 improvement, while comorbid GERD (β = 7.50, 95% CI: 3.42-11.58) and asthma (β = 5.62, 95% CI: 0.80-10.45) were negatively associated with improvement.

CONCLUSION

Surgical correction of nasal obstruction may improve ETD symptoms.

Environmental Risk Factors for Pediatric Epistaxis vary by Climate Zone

INTRODUCTION AND OBJECTIVE

Prior studies have provided variable results regarding environmental risk factors for epistaxis. These studies were conducted in varying climate zones, which may explain discrepancies in results. The objective of this study is to investigate correlations between season, temperature, and humidity on frequency of pediatric epistaxis across climate zones.

METHODS

Children seen in the outpatient setting for epistaxis were identified from the 2007-2010 IBM MarketScan database. Climate zones were assigned according to International Energy Conservation Code (IECC) classification, where temperature zones in the United States and territories were assigned on an ordinal scale from 1 (tropical) to 8 (subarctic), and humidity zones were categorized as moist, dry, or marine. The control population was a sample of all well-child visits matched by age and county.

RESULTS

We identified 184,846 unique children seen for epistaxis and 1,897,012 matched controls. Moderate temperature zones were associated with lower odds of epistaxis compared with the hottest and coldest zones. Humidity was associated inversely with epistaxis rates in moderate temperature zones but was not a significant predictor of epistaxis in climates with extreme heat. Additionally, summer was associated with lower odds of epistaxis compared to winter. Interestingly, however, there were significantly higher rates of cautery procedures during summer months, driven largely by increased procedures performed in clinic, as opposed to the operating room or emergency room.

CONCLUSIONS

Environmental risk factors for epistaxis vary by climate zone. The model presented reconciles prior reports and may allow for more personalized clinical management based on regional climate.

LEVEL OF EVIDENCE

3 Laryngoscope, 134:1450-1456, 2024.

An Exploratory Analysis of the Chronic Rhinosinusitis Online Support Community

Objective

To characterize the users of the largest chronic rhinosinusitis (CRS) online support communities (OSCs), describe the perceived benefits of OSCs for their users, and understand how patient medical decision making is affected by membership in OSCs.

Study Design

Cross-sectional online survey.

Setting

Online.

Methods

A cross-sectional online survey was adapted from the existing literature on patient support groups and modified for CRS patients. The survey was posted on multiple Facebook/Reddit groups aimed at providing support toward patients with CRS. Survey data was collected over 3 months and analyzed thereafter.

Results

There were 127 total participants. The majority were female (65.35%), white (76.98%), and the median age was 38 years. Just under half of patients had nasal polyps (48.67%) and 54.54% had undergone surgery. Many participants (69.42%) reported engaging in the OSC at least multiple times per month. The most common reason for joining an OSC was to learn tips on how to manage CRS (89.7%) and the most achieved goal from membership was hearing from others undergoing a similar experience (79.5%). Involvement in an OSC impacted knowledge of CRS in 87.41% of participants. Most users (81.1%) would recommend membership in an OSC and 54.33% reported the OSC influenced their medical decision-making.

Conclusion

A majority of patients with CRS who frequently engage in an OSC for CRS have a positive experience. OSCs are a resource that CRS patients utilize to manage their disease.

Social Media Utilization in Otolaryngology: A Scoping Review

OBJECTIVE

Social media (SM) is an increasingly popular medium for the medical community to engage with patients, trainees, and colleagues. This review aimed to identify reported uses of SM in otolaryngology-head and neck surgery (OHNS), assess the quality of evidence supporting these uses, and identify gaps in the literature. With the relative lack of regulatory guidelines for the development of SM content, we hypothesized that the quality of content available on SM would be highly variable.

DATA SOURCES AND METHODS

A scoping review was performed of English-language peer-reviewed studies published to date discussing SM use in any form within OHNS. Three reviewers independently screened all abstracts. Two reviewers independently extracted data of interest from the full text of articles identified from the preliminary abstract screen.

RESULTS

171 studies were included, with 94 (54.9%) studies published between 2020 and 2022. 104 (60.8%) studies were conducted in the US. 135 (78.9%) used cross-sectional or survey-based methodology; only 7 (4.1%) were controlled studies. SM was most commonly employed for professional networking (n = 37 [21%]), and within subspecialties of otology (n = 38 [22%]) and rhinology/allergy (n = 25 [15%]). Facebook was most frequently used for study recruitment (n = 23 [13.5%]), YouTube for patient education (n = 15 [14.6%]), and Twitter for professional networking (n = 16 [9.4%]).

CONCLUSION

SM use within OHNS is increasing rapidly, with applications including patient education, professional networking, and study recruitment. Despite myriad articles, there remains a paucity of well-controlled studies. As SM becomes integrated into healthcare, particularly for applications directly impacting patient care, higher levels of evidence are needed to understand its true impact. Laryngoscope, 133:2447-2456, 2023.

Development of a shortwave infrared sinuscope for the detection of cerebrospinal fluid leaks

Significance

Cerebrospinal fluid (CSF) rhinorrhea (leakage of brain fluid from the nose) can be difficult to identify and currently requires invasive procedures, such as intrathecal fluorescein, which requires a lumbar drain placement. Fluorescein is also known to have rare but significant side effects including seizures and death. As the number of endonasal skull base cases increases, the number of CSF leaks has also increased for which an alternative diagnostic method would be highly advantageous to patients.

Aim

We aim to develop an instrument to identify CSF leaks based on water absorption in the shortwave infrared (SWIR) without the need of intrathecal contrast agents. This device needed to be adapted to the anatomy of the human nasal cavity while maintaining low weight and ergonomic characteristics of current surgical instruments.

Approach

Absorption spectra of CSF and artificial CSF were obtained to characterize the absorption peaks that could be targeted with SWIR light. Different illumination systems were tested and refined prior to adapting them into a portable endoscope for testing in 3D-printed models and cadavers for feasibility.

Results

We identified CSF to have an identical absorption profile as water. In our testing, a narrowband laser source at 1480 nm proved superior to using a broad 1450 nm LED. Using a SWIR enabling endoscope set up, we tested the ability to detect artificial CSF in a cadaver model.

Conclusions

An endoscopic system based on SWIR narrowband imaging can provide an alternative in the future to invasive methods of CSF leak detection.

Implementation of a Standardized Perioperative Pain Management Protocol to Reduce Opioid Prescriptions in Otolaryngologic Surgery

OBJECTIVE

To evaluate the efficacy of implementing a standardized multimodal perioperative pain management protocol in reducing opioid prescriptions following otolaryngologic surgery.

STUDY DESIGN

Retrospective cohort study.

SETTING

County hospital otolaryngology practice.

METHODS

A perioperative pain management protocol was implemented in adults undergoing otolaryngologic surgery. This protocol included preoperative patient education and a postoperative multimodal pain regimen stratified by pain level: mild, intermediate, and high. Opioid prescriptions were compared between patient cohorts before and after protocol implementation. Patients in the pain protocol were surveyed regarding pain levels and opioid use.

RESULTS

We analyzed 210 patients (105 preprotocol and 105 postprotocol). Mean ± SD morphine milligram equivalents (MMEs) prescribed decreased from 132.5 ± 117.8 to 53.6 ± 63.9 (P < .05) following protocol implementation. Mean MMEs prescribed significantly decreased (P < .05) for each procedure pain tier: mild (107.4 to 40.5), intermediate (112.8 to 48.1), and high (240.4 to 105.0). Mean MMEs prescribed significantly decreased (P < .05) for each procedure type: endocrine (105.6 to 44.4), facial plastics (225.0 to 50.0), general (160.9 to 105.7), head and neck oncology (138.6 to 77.1), laryngology (53.8 to 12.5), otology (77.5 to 42.9), rhinology (142.2 to 44.4), and trauma (288.0 to 24.5). Protocol patients reported a mean 1-week postoperative pain score of 3.4, used opioids for a mean 3.1 days, and used only 39% of their prescribed opioids.

CONCLUSION

Preoperative counseling and standardization of a multimodal perioperative pain regimen for otolaryngology procedures can effectively lower amount of opioid prescriptions while maintaining low levels of postoperative pain.

Venous thromboembolism rates and risk factors following endoscopic skull base surgery

BACKGROUND

Venous thromboembolism (VTE) is a potentially fatal perioperative complication. The objective of this study was to assess the rate and risk factors for VTE in endoscopic skull base surgery (ESBS).

METHODS

This was a retrospective review of adults undergoing ESBS at a tertiary academic center. Incidence of VTE in the 30-day postoperative period was recorded. Logistic regression analyses identified factors associated with VTE.

RESULTS

1122 ESBS cases between 2009 and 2019 were studied. Almost no cases (96.1%) employed perioperative VTE chemoprophylaxis. The overall incidence of VTE was 2.3% (26/1122). Malignant pathologies had a higher rate of VTE compared to nonmalignant pathologies (4.5% vs 2.0%, OR 2.85, 95%CI 1.22-6.66). Factors associated with an increased risk of VTE included a Caprini score greater than 5 (OR 1.53, 95% CI 1.28-1.83); multiple preoperative endocrinopathies such as the syndrome of inappropriate antidiuretic hormone secretion (SIADH) (OR 22.48, 95% CI 3.93-128.70), adrenal insufficiency (OR 5.24, 95% CI 1.82-15.03), hypercortisolism (OR 4.46, 95% CI 1.47-13.56), and hypothyroidism (OR 3.69, 95% CI 1.66-8.20), each 10-hour increment of lumbar drain duration (OR 1.16, 95%CI 1.08-1.25), and each 10-hour increment for duration of hospitalization (OR 1.05, 95% CI 1.03-1.06).

CONCLUSIONS

The incidence of VTE following ESBS is relatively low. Factors with a higher association with VTE include malignancy, preoperative endocrinopathies, higher Caprini score, prolonged lumbar drain duration, and prolonged hospitalization. Further study is needed to validate these findings and to refine clinical decision making around perioperative VTE prophylaxis. This article is protected by copyright. All rights reserved.

Long-Term Outcomes of Inferior Meatus Augmentation Procedure to Treat Empty Nose Syndrome

OBJECTIVES/HYPOTHESIS

We sought to report the long-term, symptom-focused, prospective outcomes in empty nose syndrome (ENS) patients after undergoing inferior meatus augmentation procedure (IMAP) through use of four validated questionnaires: Empty Nose Syndrome 6-Item Questionnaire (ENS6Q), 22-item Sino-Nasal Outcome Test (SNOT-22), Generalized Anxiety Disorder 7-Item Scale (GAD-7), and Patient Health Questionnaire-9 (PHQ-9).

STUDY DESIGN

Prospective case series.

METHODS

A single-center prospective case series was performed for patients diagnosed with ENS who underwent IMAP between July 2017 and February 2020. Diagnosis of ENS was based on the following criteria: 1) reported discomfort with nasal breathing and/or paradoxical nasal obstruction after inferior turbinate reduction, 2) a positive ENS6Q score of at least 11, and 3) a positive cotton test. Questionnaire responses were recorded prior to surgery as well as 1, 3, 6, and 12 months postoperatively.

RESULTS

Seventeen eligible patients were included. Mean ENS6Q scores were significantly reduced at all postoperative time points (p < .0001, p < .0001, p < .0001, p = .0003). Of the six ENS6Q subdomains, five (suffocation, dryness, sense of diminished airflow, nasal crusting, and nasal burning) were significantly reduced 1-year postoperatively (p < .0001, p = .0004, p = .0136, p = .0114, p = .0080, respectively). SNOT-22 scores were significantly reduced at all time points (p = .0021, p = .0227, p = .0004, and p = .0025). Of the SNOT-22 subdomains, the sleep subdomain was significantly reduced 1-year postoperatively (p = .0432). Low baseline GAD-7 and PHQ-9 scores were recorded at 7 and 9.4, respectively, and although scores at all postoperative time points were reduced, there was no statistical significance.

CONCLUSION

IMAP via implant of cadaveric rib cartilage provides significant, long-term improvements in ENS-specific and general sinonasal symptoms.

LEVEL OF EVIDENCE

4 Laryngoscope, 131:E2736-E2741, 2021.

Oral Corticosteroids Following Endoscopic Sinus Surgery for Chronic Rhinosinusitis Without Nasal Polyposis: A Randomized Clinical Trial

Importance

Although oral corticosteroids are commonly prescribed following endoscopic sinus surgery (ESS) for chronic rhinosinusitis (CRS) without nasal polyposis, there are little data to suggest that this is a beneficial practice.

Objective

To assess the efficacy of oral corticosteroids following ESS in CRS without polyps.

Design, Setting, and Participants

This prospective double-blinded, placebo-controlled, randomized noninferiority clinical trial conducted in a single academic tertiary rhinology practice included adults with CRS without polyps undergoing ESS. Of 81 patients recruited, 72 completed the study.

Interventions

Patients were randomized into 2 treatment groups: a 12-day postoperative taper of oral prednisone vs matched placebo tablets. All study patients also received a uniform 2-week postoperative regimen of oral antibiotics, fluticasone nasal spray, and saline rinses.

Main Outcomes and Measures

The primary outcome measures were Sinonasal Outcome Test-22 (SNOT-22) scores and Lund-Kennedy endoscopy scores, collected preoperatively and postoperatively at 1 week, 1 month, 3 months, and 6 months. Scores were compared between treatment groups at each time point using longitudinal difference between treatment groups and analyzed using 2-way, repeated measures analysis of variance. Secondary outcome measures included treatment-related adverse effects.

Results

Overall, 72 patients (mean [SD] age, 49.4 [14.9] years; 36 men, 36 women) completed the study, with 33 in the prednisone arm and 39 in the placebo arm. When comparing longitudinal differences between treatment groups, there was no clinically meaningful difference observed in SNOT-22 total (F[4254] = 1.71, η2 = 0.01 [95% CI, 0.00-0.05]) or Lund-Kennedy scores (F[4247] = 1.23, η2 = 0.02 [95% CI, 0.00-0.50]). In SNOT-22 subdomain analyses, there was no clinically meaningful difference between treatment groups for rhinologic, extranasal rhinologic, ear/facial, or sleep subdomains. However, the prednisone group had worse longitudinal scores for psychological dysfunction compared with the placebo group (F[4254] = 3.18, η2 = 0.05 [95% CI, 0.02-0.09]). Reported adverse effects were similar between the 2 treatment groups.

Conclusions and Relevance

In this randomized clinical trial of patients with CRS without polyps, oral prednisone following ESS conferred no additional benefit over placebo in terms of SNOT-22 total scores, SNOT-22 rhinologic subscores, or Lund-Kennedy endoscopy scores up to 6 months after surgery. Patients receiving prednisone, however, did demonstrate worse SNOT-22 psychologic subdomain scores. These results suggest that the risks of oral corticosteroids may outweigh the benefits; thus use of oral corticosteroids after ESS for CRS without polyps should be carefully considered.

Trial Registration

ClinicalTrials.gov Identifier: NCT02748070.

A functional genomics screen identifying blood cell development genes in Drosophila by undergraduates participating in a course-based research experience

Undergraduate students participating in the UCLA Undergraduate Research Consortium for Functional Genomics (URCFG) have conducted a two-phased screen using RNA interference (RNAi) in combination with fluorescent reporter proteins to identify genes important for hematopoiesis in Drosophila. This screen disrupted the function of approximately 3500 genes and identified 137 candidate genes for which loss of function leads to observable changes in the hematopoietic development. Targeting RNAi to maturing, progenitor, and regulatory cell types identified key subsets that either limit or promote blood cell maturation. Bioinformatic analysis reveals gene enrichment in several previously uncharacterized areas, including RNA processing and export and vesicular trafficking. Lastly, the participation of students in this course-based undergraduate research experience (CURE) correlated with increased learning gains across several areas, as well as increased STEM retention, indicating that authentic, student-driven research in the form of a CURE represents an impactful and enriching pedagogical approach.

The Effect of Endoscopic Sinus Surgery on Eustachian Tube Dysfunction Symptoms

OBJECTIVE

We assessed how eustachian tube dysfunction (ETD) changed with endoscopic sinus surgery (ESS) and identified factors associated with improvement.

STUDY DESIGN

Retrospective chart review.

SETTING

Academic center.

SUBJECTS AND METHODS

Patients undergoing ESS for chronic rhinosinusitis with and without nasal polyposis (CRSwNP, CRSsNP) or recurrent acute rhinosinusitis (RARS) completed the Eustachian Tube Dysfunction Questionnaire 7 (ETDQ-7) preoperatively and postoperatively at 2 weeks, 6 weeks, 3 months, and 6 months. Included in analyses were demographics, comorbidities, Sinonasal Outcome Test 22 (SNOT-22), radiographic score, endoscopy score, procedure, and medication use. Regression analysis identified factors associated with improvement, defined as ΔETDQ-7 >3.5.

RESULTS

In total, 302 patients were studied. ETD prevalence was 68% in CRSsNP, 48% in CRSwNP, and 88% in RARS. Patients with ETD had a mean baseline ETDQ-7 of 25.8 ± 8.0 and improved postoperatively at 2 weeks (19.9 ± 8.1, P < .001), 6 weeks (17.8 ± 9.3, P < .001), 3 months (16.8 ± 8.5, P < .001), and 6 months (16.4 ± 7.9, P < .001). At 6 months, ETD improved in 89% of patients with CRSsNP, 68% with CRSwNP, and 78% with RARS. On multivariate analysis, ETD improvement was associated with higher preoperative ETDQ-7 score (adjusted odds ratio [aOR], 1.12; 95% confidence interval [CI], 1.04-1.22; P = .030), higher preoperative SNOT-22 score (aOR, 1.02; 95% CI, 1.02-1.08; P = .001), higher preoperative SNOT-22 ear subscore (aOR, 1.27; 95% CI, 1.02-1.65; P = .034), posterior ethmoidectomy (aOR, 1.59; 95% CI, 1.22-4.92; P = .025), and postoperative corticosteroid spray use (aOR, 1.57; 95% CI, 1.17-1.66; P = .008).

CONCLUSION

ETD symptoms often improve following ESS. Factors associated with improvement include higher preoperative disease burden, posterior ethmoidectomy, and postoperative corticosteroid spray.

LEVEL OF EVIDENCE

4.

Hemodynamic changes in patients undergoing office-based sinus procedures under local anesthesia

BACKGROUND

The objective of this study is to characterize changes in hemodynamics, pain, and anxiety during office-based endoscopic sinus procedures performed under local anesthesia.

METHODS

We conducted a prospective study of adults undergoing in-office endoscopic sinus procedures under local anesthesia. Patients with American Society of Anesthesiologists (ASA) Physical Status Classification System class 1 or 2 were included. Anesthesia was administered by topical 4% lidocaine/oxymetazoline and submucosal injection of 1% lidocaine/1:200,000 epinephrine. Vital signs and pain were measured at baseline, postinjection, and 5-minute intervals throughout the procedure. Anxiety levels were scored using the State-Trait Anxiety Inventory (STAI). Univariate and multivariate regression analyses were performed to identify factors significantly associated with changes in each hemodynamic metric.

RESULTS

Twenty-five patients were studied. This cohort was 52% male, mean age of 57.8 ± 14.4 years, and Charlson Comorbidity Index (CCI) median of 2. Mean procedure duration was 25.0 ± 10.3 minutes. Mean maximal increase in systolic blood pressure (SBP) was 24.6 ± 17.8 mmHg from baseline. Mean maximal heart rate increase was 22.8 ± 10.8 beats per minute (bpm) from baseline. In multivariate regression analysis, when accounting for patient age, cardiac comorbidity, CCI, and ASA, older age was significantly associated with an increase of >20 mmHg in SBP (p = 0.043). Mean pain score during procedures was 1.5 ± 1.3 with a mean maximum of 4.0 ± 2.6. STAI anxiety scores did not change significantly from preprocedure to postprocedure (32.8 ± 11.6 to 31.0 ± 12.6, p = 0.46). No medical complications occurred.

CONCLUSION

Although patients appear to tolerate office procedures well, providers should recognize the potential for significant fluctuations in blood pressure during the procedure, especially in older patients.

Cryosurgical ablation for treatment of rhinitis: A prospective multicenter study

Objective

To assess the efficacy and safety of cryoablation of the posterior nasal nerve (PNN) for treatment of chronic rhinitis.

Methods

This was a prospective single‐arm trial of 98 adult patients at six U.S. centers with chronic allergic and nonallergic rhinitis. PNN cryoablation was performed in‐office under local anesthesia using a handheld device. Patients discontinued use of intranasal ipratropium 3 days prior to treatment and throughout the study period. Reflective Total Nasal Symptom Score (rTNSS) was measured at pretreatment baseline and posttreatment at 1 month, 3 months, 6 months, and 9 months. The Rhinoconjunctivitis Quality of Life Questionnaire (RQLQ) was completed at pretreatment and 3 months posttreatment. Adverse effects and postprocedure medication usage were recorded.

Results

Ninety‐eight procedures (100%) were successfully completed. rTNSS significantly improved over pretreatment baseline (6.1 ± 1.9) at 1 month (2.9 ± 1.9, P < 0.001), 3 months (3.0 ± 2.3, P < 0.001), 6 months (3.0 ± 2.1, P < 0.001), and 9 months (3.0 ± 2.4, P < 0.001) postprocedure. Nasal congestion and rhinorrhea subscores improved significantly at all time points (P < 0.001). Both allergic and nonallergic rhinitis subcohorts showed improvement (P < 0.001), with a comparable degree of improvement between groups. RQLQ significantly improved over pretreatment baseline (3.0 ± 1.0) at 3 months (1.5 ± 1.0, P < 0.001), and all RQLQ subdomains demonstrated improvement. Of 54 patients using intranasal medication at baseline, 19 (35.2%) were able to discontinue use. Twenty‐nine adverse effects were reported, including headache, epistaxis, and sinusitis.

Conclusion

Cryoablation of the PNN for chronic rhinitis is safe and can result in relief of nasal symptoms and improvements in quality of life.

Level of Evidence

4 Laryngoscope, 130: 1877–1884, 2020

Operative Management of Vocal Fold Avulsion Following Pediatric Laryngotracheal Separation

Laryngotracheal disruption in children is rare but life-threatening, and endolaryngeal injuries may go overlooked. We present the case of a 10-year-old boy who sustained near-complete laryngotracheal separation, multiple laryngeal fractures, and arytenoid and vocal fold avulsion following blunt cervical trauma. These injuries were not identified radiographically and only became apparent intraoperatively. Following surgical repair, the patient was successfully decannulated, eating a normal diet, and had a serviceable speaking voice within 2 months. In children, the diagnosis of severe endolaryngeal injuries may be elusive and therefore require high degree of clinical suspicion. Surgical success requires accurate diagnosis and prompt intervention.

The 50 Most Cited Articles in Facial Plastic Surgery

Bibliometric analysis is a common method to determine the most influential articles in medical specialties, as it is an objective measure of peer recognition of scientific work. This study is the first bibliometric analysis of the literature in facial plastic surgery, to determine the most cited papers in the field. Bibliometric analysis was performed using the Science Citation Index from the Institute for Scientific Information, accessed through the Web of Science™. Filter terms relevant to the field of facial plastic surgery were used to identify the 50 most cited journal articles between 1900 and 2016. The median number of citations was 150 (range 116-1091). The articles spanned a wide range of topics in the field, with the most common topics being free flap reconstruction (n = 10), nasal surgery (n = 9), and rhytidectomy (n = 6). The majority of these articles (n = 29) presented findings supported by level IV or V evidence. This analysis provides an overview of the most cited articles in facial plastic surgery, many of which introduced some of the most fundamental principles and techniques in the field. These landmark articles represent important educational points that should be reviewed by all clinicians and trainees in this field. Level of Evidence III This journal requires that authors assign a level of evidence to each article. For a full description of these Evidence-Based Medicine ratings, please refer to the Table of Contents or the online Instructions to Authors www.springer.com/00266 .

Broad expansion of optical frequency combs by self-Raman scattering in coupled-cavity self-mode-locked monolithic lasers

Broad expansion of optical frequency comb (OFC) by the self-Raman scattering is numerically analyzed and experimentally accomplished in a coupled-cavity self-mode-locked (SML) monolithic Yb:KGW laser. The gain medium is coated to achieve the monolithic SML operation and a partially reflective mirror is further exploited to form the coupled cavity and to multiply the repetition rate up to 128.9 GHz. With a coupled reflectivity of 95%, it is experimentally found that not only the first-order but also second-order stimulated Raman scattering (SRS) can be efficiently generated. The mode-locked OFC can be consequently expanded to reach approximately 8.4 THz, leading the pulse width to be as narrow as 53 fs. At the pump power of 8.7 W, the total output power for the fundamental and the first- and second-Stokes waves can be maintained at 1.6 W. The present exploration provides a promising way to generate the ultrahigh-repetition-rate broadband OFC via the simultaneous SML and SRS processes.

NOTCH1 and SOX10 are Essential for Proliferation and Radiation Resistance of Cancer Stem-Like Cells in Adenoid Cystic Carcinoma

PURPOSE

Although the existence of cancer stem cells (CSC) in adenoid cystic carcinoma (ACC) has been proposed, lack of assays for their propagation and uncertainty about molecular markers prevented their characterization. Our objective was to isolate CSC from ACC and provide insight into signaling pathways that support their propagation.

EXPERIMENTAL DESIGN

To isolate CSC from ACC and characterize them, we used ROCK inhibitor-supplemented cell culture, immunomagnetic cell sorting, andin vitro/in vivoassays for CSC viability and tumorigenicity.

RESULTS

We identified in ACC CD133-positive CSC that expressed NOTCH1 and SOX10, formed spheroids, and initiated tumors in nude mice. CD133(+)ACC cells produced activated NOTCH1 (N1ICD) and generated CD133(-)cells that expressed JAG1 as well as neural differentiation factors NR2F1, NR2F2, and p27Kip1. Knockdowns ofNOTCH1, SOX10, and their common effectorFABP7had negative effects on each other, inhibited spheroidogenesis, and induced cell death pointing at their essential roles in CSC maintenance. Downstream effects ofFABP7knockdown included suppression of a broad spectrum of genes involved in proliferation, ribosome biogenesis, and metabolism. Among proliferation-linked NOTCH1/FABP7 targets, we identified SKP2 and its substrate p27Kip1. A γ-secretase inhibitor, DAPT, selectively depleted CD133(+)cells, suppressed N1ICD and SKP2, induced p27Kip1, inhibited ACC growthin vivo, and sensitized CD133(+)cells to radiation.

CONCLUSIONS

These results establish in the majority of ACC the presence of a previously uncharacterized population of CD133(+)cells with neural stem properties, which are driven by SOX10, NOTCH1, and FABP7. Sensitivity of these cells to Notch inhibition and their dependence on SKP2 offer new opportunities for targeted ACC therapies.

Clinical and molecular insights into adenoid cystic carcinoma: Neural crest-like stemness as a target

OBJECTIVES

This review surveys trialed therapies and molecular defects in adenoid cystic carcinoma (ACC), with an emphasis on neural crest-like stemness characteristics of newly discovered cancer stem cells (CSCs) and therapies that may target these CSCs.

DATA SOURCES

Articles available on Pubmed or OVID MEDLINE databases and unpublished data.

REVIEW METHODS

Systematic review of articles pertaining to ACC and neural crest-like stem cells.

RESULTS

Adenoid cystic carcinoma of the salivary gland is a slowly growing but relentless cancer that is prone to nerve invasion and metastases. A lack of understanding of molecular etiology and absence of targetable drivers has limited therapy for patients with ACC to surgery and radiation. Currently, no curative treatments are available for patients with metastatic disease, which highlights the need for effective new therapies. Research in this area has been inhibited by the lack of validated cell lines and a paucity of clinically useful markers. The ACC research environment has recently improved, thanks to the introduction of novel tools, technologies, approaches, and models. Improved understanding of ACC suggests that neural crest-like stemness is a major target in this rare tumor. New cell culture techniques and patient-derived xenografts provide tools for preclinical testing.

CONCLUSION

Preclinical research has not identified effective targets in ACC, as confirmed by the large number of failed clinical trials. New molecular data suggest that drivers of neural crest-like stemness may be required for maintenance of ACC; as such, CSCs are a target for therapy of ACC.

Exploring transverse pattern formation in a dual-polarization self-mode-locked monolithic Yb: KGW laser and generating a 25-GHz sub-picosecond vortex beam via gain competition

Formation of transverse modes in a dual-polarization self-mode-locked monolithic Yb: KGW laser under high-power pumping is thoroughly explored. It is experimentally observed that the polarization-resolved transverse patterns are considerably affected by the pump location in the transverse plane of the gain medium. In contrast, the longitudinal self-mode-locking is nearly undisturbed by the pump position, even under the high-power pumping. Under central pumping, a vortex beam of the Laguerre-Gaussian LGp,l mode with p = 1 and l = 1 can be efficiently generated through the process of the gain competition with a sub-picosecond pulse train at 25.3 GHz and the output power can be up to 1.45 W at a pump power of 10.0 W. Under off-center pumping, the symmetry breaking causes the transverse patterns to be dominated by the high-order Hermite-Gaussian modes. Numerical analyses are further performed to manifest the symmetry breaking induced by the off-center pumping.

High rate of bilaterality in internal auditory canal metastases

PURPOSE

Presentation of three cases of metastatic carcinoma to the internal auditory canal bilaterally, as well as a systematic review of the literature regarding the characteristics of these lesions.

MATERIALS AND METHODS

Using a MEDLINE Ovid search (1946-2015), we identified and reviewed 102 cases of metastatic carcinoma to the internal auditory canal. Metrics recorded include: patient age, sex, tumor type, laterality, past oncologic history, co-occurring metastatic sites, clinical findings, radiographic findings, therapy received, and outcome. Cases of unilateral versus bilateral IAC were compared.

RESULTS

Remarkably, 52.9% reported cases of internal auditory canal metastases have bilateral occurrence. The most common primary tumor sites for internal auditory canal metastases were lung (21.2%), skin (18.6%), and breast (16.7%), with lung and skin cancers having the highest rates of bilateral metastasis. Meningeal metastasis occurred at a much higher rate in bilateral cases (47.2%) versus unilateral cases (8.5%). Brain parenchymal metastasis also occurred at a higher rate in bilateral cases (38.2%) versus unilateral cases (19.2%). Outcomes for cases of internal auditory canal metastases are generally poor, with 56.3% of unilateral cases and 86.1% of bilateral cases reporting patient death within 5 years from diagnosis.

CONCLUSIONS

In cases of internal auditory canal metastasis, clinicians should carefully assess for not only contralateral disease but also additional metastatic disease of the central nervous system. Rapid-onset hearing loss, tinnitus, vertigo, or facial palsy should raise suspicion for internal auditory canal metastasis, particularly in patients with a known oncologic history.

Severe epistaxis due to aberrant vasculature in a patient with STAT-1 mutation

BACKGROUND

Signal transducer and activator 1 (STAT-1) mutations are rare and have been implicated in combined immunodeficiency, enhanced tumorigenesis, and vascular defects.

METHODS

A 60-year-old woman with a novel STAT-1 mutation and resulting immunodeficiency, squamous cell carcinoma, and vascular disease presented with profuse epistaxis secondary to rupture of an aberrant artery that she developed in part because of this mutation. After unsuccessful posterior packing, embolization was initiated but subsequently aborted because of a bovine origin carotid artery and a history of multiple carotid dissections.

RESULTS

After repeat posterior packing, hemostasis was achieved. No additional episodes of epistaxis occurred in the subsequent 13 months.

CONCLUSION

Vascular anomalies can present challenges in epistaxis management. In patients with conditions known to cause vascular anomalies, it is critical to obtain vascular imaging before intervention.

Dual-comb self-mode-locked monolithic Yb:KGW laser with orthogonal polarizations

The dependence of lasing threshold on the output transmission is numerically analyzed to find the condition for the gain-to-loss balance for the orthogonal Np and Nm polarizations with a Ng-cut Yb:KGW laser crystal. With the numerical analysis, an orthogonally polarized dual-comb self-mode-locked operation is experimentally achieved with a coated Yb:KGW crystal to form a monolithic cavity. At a pump power of 5.2 W, the average output power, the pulse repetition rate, and the pulse duration are measured to be 0.24 (0.6) W, 25.8 (25.3) GHz, and 1.06 (1.12) ps for the output along the Np (Nm) polarization.

Effectiveness of a segmental approach to climate policy

Resistance to adopting a cap on greenhouse gas emissions internationally, and across various national contexts, has encouraged alternative climate change mitigation proposals. These proposals include separately targeting clean energy uptake and demand-side efficiency in individual end-use sectors, an approach to climate change mitigation which we characterize as segmental and technology-centered. A debate has ensued on the detailed implementation of these policies in particular national contexts, but less attention has been paid to the general factors determining the effectiveness of a segmental approach to emissions reduction. We address this topic by probing the interdependencies of segmental policies and their collective ability to control emissions. First, we show for the case of U.S. electricity how the set of suitable energy technologies depends on demand-side efficiency, and changes with the stringency of climate targets. Under a high-efficiency scenario, carbon-free technologies must supply 60-80% of U.S. electricity demand to meet an emissions reduction target of 80% below 1990 levels by midcentury. Second, we quantify the enhanced propensity to exceed any intended emissions target with this approach, even if goals are set on both the supply and demand side, due to the multiplicative accumulation of emissions error. For example, a 10% error in complying with separate policies on the demand and supply side would combine to result in a 20% error in emissions. Third, we discuss why despite these risks, the enhanced planning capability of a segmental approach may help counteract growing infrastructural inertia. The emissions reduction impediment due to infrastructural inertia is significant in the electricity sectors of each of the greatest emitters: China, the U.S., and Europe. Commonly cited climate targets are still within reach but, as we show, would require more than a 50% reduction in the carbon intensity of new power plants built in these regions over the next decade.

Efficient continuous-wave self-Raman Yb:KGW laser with a shift of 89 cm⁻¹

We demonstrated a continuous-wave (CW) self-Raman laser with high conversion efficiency by using Yb:KGW as the Raman crystal. The first Stokes line of wavelength centered at 1095.2 nm with spectral bandwidth of 8 nm and the cascaded Raman conversion wavelength at 1109.5 nm with spectral bandwidth of 3.4 nm were observed with a Raman shift of 89 cm⁻¹ with respect to the fundamental laser wavelength at 1085.0 nm with spectral bandwidth of 10 nm. The CW Raman output power of 1.7 W was attained under the diode pump power of 7.8 W which corresponds to the slope efficiency and the diode-to-Stokes optical conversion efficiency of 26.6% and 21.8%, respectively.

High-power high-repetition-rate subpicosecond monolithic Yb:KGW laser with self-mode locking

We report on a high-power subpicosecond monolithic self-mode-locked Yb:KGW laser with the pulse repetition rate up to several tens of gigahertz. Experimental results reveal that not only the repetition rate but also the pulse width depend on the length of the laser crystal. Using a coated Yb:KGW crystal with a length of 3.36 mm, mode-locked pulses with pulse duration of 850 fs at the repetition rate of 22.4 GHz have been achieved. With an incident pump power of 10.5 W, an average output power of 3.6 W was achieved which corresponds to the optical conversion efficiency of 34.3%.

Biomechanical effects of simulated resorption cavities in cancellous bone across a wide range of bone volume fractions

Resorption cavities formed during bone remodeling may act as "stress risers" and impair cancellous bone strength, but biomechanical analyses of the effects of stress risers have been limited. To provide further insight, we assessed the theoretical biomechanical effects of virtually-added resorption cavities in cancellous bone specimens spanning a wide range of bone volume fraction (BV/TV = 0.05-0.36) and across different anatomic sites (hip and spine) and species (human and canine). Micro-CT scans of 40 cubes of cancellous bone were converted into nonlinear finite element models (voxel element size ∼ 20 µm) for strength assessment. In each model, uniform trench-like resorption cavities with nominal dimensions 500 µm (length) × 200 µm (width) × 40 µm (depth), were virtually added either at random locations throughout the specimen, or, preferentially at locations of high tissue-level strain. We found that cancellous bone strength (p < 0.0001) and its relation with BV/TV (p < 0.001) were both altered by the virtual addition of the resorption cavities. When the resorption cavities were added at random locations throughout the specimen, the reduction in strength did not depend on BV/TV or anatomic site or species. When the resorption cavities were instead added preferentially at locations of high tissue-level strain, the effect was accentuated and was greatest in low-BV/TV bone. We conclude that, in theory, uniform-sized resorption cavities can reduce cancellous bone strength over the full range of BV/TV and across species, and the effect is larger if the cavities occur at highly strained locations in low-BV/TV bone.

Quantifying interhospital patient sharing as a mechanism for infectious disease spread

BACKGROUND

Assessments of infectious disease spread in hospitals seldom account for interfacility patient sharing. This is particularly important for pathogens with prolonged incubation periods or carrier states.

METHODS

We quantified patient sharing among all 32 hospitals in Orange County (OC), California, using hospital discharge data. Same-day transfers between hospitals were considered "direct" transfers, and events in which patients were shared between hospitals after an intervening stay at home or elsewhere were considered "indirect" patient-sharing events. We assessed the frequency of readmissions to another OC hospital within various time points from discharge and examined interhospital sharing of patients with Clostridium difficile infection.

RESULTS

In 2005, OC hospitals had 319,918 admissions. Twenty-nine percent of patients were admitted at least twice, with a median interval between discharge and readmission of 53 days. Of the patients with 2 or more admissions, 75% were admitted to more than 1 hospital. Ninety-four percent of interhospital patient sharing occurred indirectly. When we used 10 shared patients as a measure of potential interhospital exposure, 6 (19%) of 32 hospitals "exposed" more than 50% of all OC hospitals within 6 months, and 17 (53%) exposed more than 50% within 12 months. Hospitals shared 1 or more patient with a median of 28 other hospitals. When we evaluated patients with C. difficile infection, 25% were readmitted within 12 weeks; 41% were readmitted to different hospitals, and less than 30% of these readmissions were direct transfers.

CONCLUSIONS

In a large metropolitan county, interhospital patient sharing was a potential avenue for transmission of infectious agents. Indirect sharing with an intervening stay at home or elsewhere composed the bulk of potential exposures and occurred unbeknownst to hospitals.

Comparison of BiPAP nasal ventilation and ventilation via iron lung in severe stable COPD

The effects of noninvasive ventilators on COPD remain controversial because of their obscure mechanisms. A randomized crossover study, using iron lung and positive pressure nasal ventilation (BiPAP) each for 40 min, was performed in 11 stable patients with severe COPD. Throughout the study, we monitored surface EMGdi, EMGst, ECG, SaO2, ETCO2, and the movements of RC and AB. Afterwards the data were replayed to calculate VT, RR, PR, VT/TI, iEMG, and phase angle. No statistically significant improvement was found in view of the above parameters. However, the percentage of iEMGst change after 40-min BiPAP ventilation, compared with the baseline, was much more significant in patients with FEV1 below 0.55 L than those with FEV1 above 0.55 L (n = 4:7, delta iEMGst -62.93 percent +/- 23.27 percent vs 32.45 percent +/- 42.79 percent, p = 0.0056). delta iEMGst correlated significantly with FEV1 during BiPAP ventilation (p < 0.05, r = 0.59). We conclude that the iEMGst during short-term BiPAP ventilation correlates with the severity of the disease.

Study on the concentrations of cerebrospinal fluid immunoglobulin G and albumin in children

Concentrations of immunoglobulin G (IgG) and albumin in cerebrospinal fluid (CSF) and serum were measured in 118 "normal" Chinese children from birth to 15 years old to obtain the reference values for the evaluation of the blood-brain barrier (BBB) function. The values of the CSF/serum IgG ratio, CSF/serum albumin ratio and IgG index (IgG ratio/albumin ratio) were then calculated for each subject. A relation was found between the content of IgG in CSF and serum depending on age. The gradual decrease of CSF IgG and IgG ratio during the first 6 months indicated a postnatal impediment of the diffusion of IgG from the blood to the CSF. In the meanwhile the CSF/serum albumin ratio continued to drop until the age of one year. The slower slope of the decrement of the latter ratio further demonstrated the differential permeability of the BBB in favor of the shift of small molecular protein. The change of the protein permeability within the first year of life shows a characteristic of the maturational process of the BBB. Nevertheless, IgG index has no age-dependent variation throughout the childhood period. It remains constant in the absence of inflammation within the central nervous system.

A simple method for staining nuclei of mature and germinated maize pollen

A sugar acetocarmine staining technique has been developed for staining the sperm and vegetative nucleus of mature and germinated maize pollen grains. This procedure is simple, stable and highly repeatable. The physiological properties of the mature maize pollen grains are first adjusted by using an in vitro germinating culture solution. This solution is 15% sucrose and contains 360 ppm calcium chloride dihydrate, and 120 ppm boric acid. One part fresh pollen grains is uniformly mixed with nine parts of the solution and left at room temperature for at least 5 hr. One part of this solution is then mixed with two parts of regular acetocarmine stain and left overnight. The color of this mixture is pinkish red or raspberry. The sugar in the mixture helps to increase color contrast between the pollen cytoplasm (light pink) and the nuclei (reddish purple), decreases the frequency of burst pollen, increases pollen expansion, stabilizes pollen figures and automatically seals the coverglass.

Nucleotide sequence of Lymantria dispar nuclear polyhedrosis virus polyhedrin gene

The polyhedrin gene of the nuclear polyhedrosis virus of the gypsy moth (Lymantria dispar) (LdMNPV) was cloned and sequenced. A polyhedrin open reading frame of 735 nucleotides (nt) was identified which can code for a protein of 245 amino acids that demonstrates a high degree of similarity to other polyhedrins. The protein predicted from the nucleotide sequence shows differences in several regions to that previously sequenced from the LdMNPV polyhedrin protein. The consensus sequence AATAAGTATTTT found at the mRNA start site of baculovirus hyperexpressed genes was located 55 nt upstream from the translational start site.

Nuclear, Virescent Mutants of Zea mays L. with High Levels of Chlorophyll (a/b) Light-Harvesting Complex during Thylakoid Assembly

We have found nuclear, recessive mutants in Zea mays L. where assembly of the major chlorophyll (a/b) light-harvesting complex (LHC) was not delayed relative to most other thylakoid protein complexes during thylakoid biogenesis. This contrasts with the normal development of maize chloroplasts (NR Baker, R Leech 1977 Plant Physiol 60: 640-644). All four mutants examined were allelic and virescent, and displayed visibly higher yields of leaf Chl fluorescence during greening. Fully greened mutants had normal leaf Chl fluorescence yield and normal levels of LHC, and grew to maturity under field conditions. Therefore, delayed LHC assembly is not an obligate feature of thylakoid differentiation.Assigning the molecular basis for the mutation should provide information concerning reguation of LHC assembly. Several possibilities are discussed. The pleiotropic mutant phenotype is not attributable to defects in thylakoid glycerolipid synthesis. Thylakoids isolated from greening mutant leaf sections had elevated glycerolipid/Chl ratios. In addition, both the molar distribution and acyl composition of four major glycerolipids were normal for developing mutant thylakoids.

Comparison of three tests for virulent Yersinia enterocolitica

Magnesium oxalate agar was found to select against virulent types of Yersinia enterocolitica. Small colonies isolated from magnesium oxalate agar which were presumably virulent generally contained no detectable virulence-specific plasmids, did not agglutinate with virulence-specific antiserum, and exhibited various degrees of virulence in mice. Results indicate that the virulence potential of a Y. enterocolitica isolate cannot always be identified by these in vitro methods and suggest that virulence also involves other factors yet to be identified.

Identification of specific outer membrane polypeptides associated with virulent Yersinia enterocolitica

An antiserum (WA-SAA) that agglutinates specifically with mouse virulent but not avirulent strains of Yersinia enterocolitica was used to identify virulence-associated factors by Western blot techniques. Several outer membrane polypeptides were identified only in the virulent strains, which included serotypes O:8, O:3, O:9, O:4,32, O:5,27, and O:21. These included three, and possibly four, major outer membrane polypeptides. The prominent high-molecular-weight species was demonstrated by both sodium dodecyl sulfate-polyacrylamide gel electrophoresis and Western blot, whereas the others were only revealed by the Western blot technique. Expression of these polypeptides correlated with antiserum agglutination reaction and the presence of a 42- and/or 82-megadalton plasmid. These polypeptides were highly temperature dependent and only slightly affected by the inclusion of 10 mM Ca2+ in the growth medium. These polypeptides were produced during both the logarithmic and stationary phases of growth at 37 degrees C. We suggest that the production of these specific polypeptides and calcium dependency may be coded for by the plasmid(s) but are regulated by independent mechanisms. These polypeptides appear to be novel markers specific for virulent strains of Y. enterocolitica and may be important to the pathogenicity of this organism.

The effect of light on morphogenesis of Dictyostelium mucoroides

The effect of light on the production of macrocysts and sorocarps of Dictyostelium mucoroides, strain DM-7, has been studied with surface cultures grown on dilute lactose-peptone agar at 22 degrees C with Escherichia coli, strain B/r, as food bacteria. The production of sorocarps or macrocysts can be controlled by altering the light component of the environment. Far red light had no effect on macrocyst production, whereas visible light from 440 to 700 nm inhibited macrocyst production with production decreasing with increasing light intensity. Fluence response curves for macrocyst production were determined for twelve wavelengths of light between 400 and 700 nm. An action spectrum calculated from the fluence response curves shows a single major peak at about 425-430 nm.

The periodic synthesis of tubulin in the Physarum cell cycle. Characterization of Physarum tubulins by affinity for monoclonal antibodies and by peptide mapping

Polypeptides preferentially labeled in the G2 phase of the synchronous nuclear replication cycle of Physarum macroplasmodia were compared in electrophoretic mobility and peptide map with the tubulins enriched from Physarum myxamoebae. One major and one minor fluorographic species match the myxamoebal alpha and beta chains, respectively. Thus, tubulins are among the proteins of Physarum selectively synthesized before nuclear division. A third species P, prominently labeled in premitotic plasmodia, is distinct from the two myxamoebal tubulins even though it co-polymerizes with microtubules. The nature of P remains unknown. Two rat monoclonal antibodies directed against yeast tubulin were found to bind selectively to the alpha tubulin of porcine brain. These served to confirm the assignment of the 50,000-dalton Physarum myxamoebal tubulin as an alpha-like polypeptide.

Serological relatedness of mouse-virulent Yersinia enterocolitica

An antiserum (WA-SAA) was produced which agglutinated specifically with mouse-virulent but not with avirulent strains of Yersinia enterocolitica. Expression of the antigenic determinant(s) reaction with WA-SAA was temperature dependent; for growth temperatures of 20 to 40 degrees C, agglutination titers were lowest for cultures grown at 20 degrees C and highest for cultures grown at 35 to 40 degrees C. Addition of Ca2+ (2.5 to 10 mM) to the growth medium had little effect on the agglutination titer, and gel diffusion studies with monospecific anti-V serum indicated that V antigen was not likely to be the determinant reacting with WA-SAA. Immunohistological studies of Peyer's patches of mice infected with Y. enterocolitica WA revealed that the antigenic determinant(s) reacting with WA-SAA was expressed in vivo. The strong correlation of agglutination titer with mouse virulence and the expression in vivo of the antigenic determinant(s) reacting with WA-SAA suggest that the antigen(s) may be associated with the pathogenicity of Y. enterocolitica.

Mating types and macrocyst formation in Dictyostelium

Macrocysts have been found among strains of Dictyostelium rosarium Raper and Cavender (K. B. Raper and J. C. Cavender, J. Elisha Mitchell Sci. Soc. 84:31-47, 1968). Strains that exhibit mating capabilities could be classified into one of three mating types: A1, A2, or A3. Each mating type was self-incompatible but cross-compatible with the other two types in most cases. No self-fertile strain was observed. Wet conditions, darkness, and moderate nutrient particularly favored macrocyst production; opposite conditions generally favored asexual sorocarp formation. Macrocyst development followed the same morphogenetic pattern reported previously for other species of Dictyostelium. Cultures exposed to light in stages prior to precyst appearance could be switched from macrocyst to sorocarp development. In contrast, precysts always developed into macrocysts despite the presence of light. There appeared to be an "all-or-none" phenomenon in macrocyst production, suggesting that transformation to macrocysts occurred once certain light-sensitive critical factors had reached a threshold level. Intimate association of cells of mating pairs appeared to be essential for macrocyst formation, and no mating hormones were detected.

Periodic synthesis of microtubular proteins in the cell cycle of Physarum

Periodic polypeptide labeling over the naturally synchronous nuclear replication cycle of Physarum polycephalum was analyzed by fluorography of two-dimensional electropherograms. Two sets of polypeptides, denoted as P and Q, showed strong periodicity; they were maximally labeled just prior to mitosis. This periodicity was shown to reflect synthesis rather than turnover or recovery. Both P and Q copolymerized with porcine microtubular proteins and displayed electrophoretic properties similar to those of porcine tubulins. The significance of the periodic synthesis of these microtubular proteins is discussed as a possible component within the chain of events that establishes the high mitotic synchrony of Physarum syncytia.

Nucleoside Diphosphate Sugar-Starch Glucosyl Transferase Activity of wx Starch Granules

Starch granule preparations from the endosperm tissue of all waxy maize (Zea mays L.) mutants tested have low and approximately equal capability to incorporate glucose from adenosine diphosphate glucose into starch. As the substrate concentration is reduced, however, the activity of waxy preparations relative to nonmutant increases until, at the lowest substrate concentration utilized (0.1 muM), the activity of the waxy preparations is nearly equal to that of the nonmutant preparation. The apparent K(m) (adenosine diphosphate glucose) for starch granule preparations from wx-C/wx-C/wx-C endosperms was 7.1 x 10(-5) M, which is compared to 3 x 10(-3) M for preparations from nonwaxy endosperms. Starch granule preparations from three other waxy mutants of independent mutational origin have levels of enzymic activity approximately equal to wx-C at a given substrate concentration giving rise to similar apparent K(m) estimates. We conclude that there is in maize endosperm starch granules a second starch granule-bound glycosyl transferase, whose presence is revealed when mutation eliminates activity of the more active glucosyl transferase catalyzing the same reaction.