Histological assessment of microtia cartilage, a potential source of autograft tissue in ear reconstruction

Cartilage is a strong and flexible connective tissue that has many forms and functions in our body. While cartilage exhibits some forms of limited repair, for the most part, it is not particularly regenerative. Thus, in situations where patients require cartilage reconstruction, surgeons may use autografts to replace missing or damaged tissue. Cartilage tissues from different regions of the body exhibit histological differences and are in limited supply. Thus, it is important to characterize these differences to determine the most appropriate autograft source. In the case of microtia, a congenital deformity where the pinna is underdeveloped, reconstruction commonly utilizes cartilage sourced from a patient's own costal cartilage. This presents a potential morbidity risk. In this study, we evaluate the histological characteristics of microtia cartilage compared with normal auricular and costal cartilage obtained from human patients undergoing surgical resection. Histochemistry was used to evaluate cellularity, lipid content, and ECM content. Using a Bayesian statistical approach, we determined that while costal cartilage is the standard tissue donor, the microanatomy of microtia cartilage more closely reflects normal auricular cartilage than costal cartilage. Therefore, microtia cartilage may serve as an additional reservoir for cartilage during reconstruction.

Salvage of Infected Alloplastic Ear Reconstructions via Negative Pressure Wound Therapy

This is the first description of Negative Pressure Wound Therapy (NPWT) use in rescuing alloplastic ear reconstructions. Previously considered a sign of certain impending failure, severe infections with frank purulence can be salvaged. As a more recently developed technique, porous polyethylene (PPE) ear reconstruction provides benefits when compared to rib techniques. Increasing surgeon awareness of complication management may lead to further adoption of the technique and improve reconstructive results. Described herein are two cases of draining infections following PPE ear reconstruction that were salvaged with satisfactory results. Laryngoscope, 2024.

Endoscopic-Indocyanine Green Angiography Assisted Microtia Reconstruction

Described herein is an innovative, minimally-invasive technique to harvest temporoparietal fascia flap used in implant-based ear reconstruction for children with microtia. This technique utilizes a never previously described application of intra-operative Indocyanine Green Angiography to optimize flap viability and minimizing the risk of facial nerve injury. Laryngoscope, 133:3615-3618, 2023.

Minimally Invasive Techniques for Facial Rejuvenation Utilizing Polydioxanone Threads

Cosmetic procedures to combat the effects of aging are increasing in demand. Surgical interventions, such as rhytidectomy, have long been the standard method of providing a more youthful appearance. However, these procedures are costly, often require general anesthesia, and have potential risks such as scarring and prolonged recovery. A safe, effective, alternative to surgery is the nonsurgical thread-lift. Nevertheless, proper patient selection is critical for optimal outcomes and for patient and provider satisfaction. Over the past decade, these treatments have gained significant popularity for patients to achieve a more rejuvenated appearance with less complications and minimal downtime.

Dual Option Microtia Clinic: A Comparison of Outcomes in Microtia Reconstruction Using Autologous Rib or Porous Polyethylene Implant

Introduction: Auricular reconstruction techniques most frequently utilize either autologous costal cartilage or alloplastic porous polyethylene (PPE) implant. Objectives: To compare the aesthetic outcomes, number of surgeries, and complications in children who underwent microtia reconstruction with either rib or PPE implant by blinded photograph review. Methods: This retrospective cohort study included consecutive pediatric patients who underwent auricular reconstruction with either autologous cartilage or PPE between November 2017 and February 2022. Blinded observers rated each postoperative ear through a web-based survey. Data on patient characteristics, operative time, length of admission, and complications were collected, bivariate analyses were performed using chi-square or Fisher's exact tests for categorical variables and Wilcoxon rank-sum test for continuous variables. Results: Forty-four ears were included, 28 of which (63.6%) were reconstructed with cartilage. Median patient age was 8 years (range 4-18 years) and 29 (65.9%) were male. The cartilage group had more surgeries (median 2.5 vs. 1.0, p < 0.001), and total operating time across all surgeries did not differ significantly. Conclusion: The two groups in our study had similar rates of complications and aesthetic scores, and aesthetic scores were worse for ears with wound complications requiring unplanned revisions.

Patient Perception of Education, Care Coordination, and Psychological Distress After Developing Facial Paralysis: A Qualitative Study

Importance

The management of vestibular schwannoma may include observation, microsurgical resection, or radiation of a tumor near the facial nerve. Injury to the facial nerve can result in facial paralysis with major functional, social, and psychological sequelae, and the experiences of patients after paralysis are not well studied.

Objective

To (1) identify patient preparedness for developing facial paralysis and how well their care is coordinated following its development and (2) present in their own words outcomes of facial paralysis in terms of physical health, emotional health, self-perception, and social interactions.

Design, Setting, and Participants

A qualitative observational study was performed using semistructured interviews at a tertiary care academic medical center. Semistructured interviews were conducted between January 1, 2018, and June 30, 2019, with adults aged 25 to 70 years who developed facial paralysis after treatment for vestibular schwannoma. Data were analyzed from July 2019 to June 2020.

Main Outcomes and Measures

Perceptions of the educational and emotional experiences of individuals who developed complete facial paralysis after surgical treatment of vestibular schwannoma.

Results

Overall, 12 participants were interviewed (median age, 54 years [range, 25-70 years]; 11 were female). Saturation was achieved after 12 interviews, indicating that no further information could be elicited from additional interviews. Four major themes were identified: (1) lack of sufficient patient education about the diagnosis of facial paralysis; (2) lack of appropriate care coordination related to facial paralysis; (3) changes in physical and emotional health following facial paralysis; and (4) changes in social interactions and external support following facial paralysis.

Conclusions and Relevance

It is well-known that patients with facial paralysis have reduced quality of life, severe psychological and emotional sequelae. However, little is currently done to help prepare patients for this undesirable outcome. In this qualitative study of facial paralysis, patients express, in their own words, their feeling that the education and management of facial paralysis by their clinicians was inadequate. Before patients undergo surgery, and certainly after injury to the facial nerve, clinicians should consider the patient's goals, preferences, and values to ensure that a comprehensive educational program and psychosocial support system are implemented. Facial reanimation research has not adequately captured these key patient factors associated with the quality of communication.

Microtia Reconstruction and Erector Spinae Block in Children: A Case Series With Chart Review

OBJECTIVES

Autologous reconstruction of microtia is advantageous due to its inherent biocompatibility and long-term stability, but postoperative pain associated with costal harvest is a significant issue. A well-planned pain management approach is imperative. Our objective is to introduce the novel application of erector spinae block anesthesia in pediatric microtia reconstruction and evaluate its impact on pain scores, use of opioids, and hospital length of stay.

STUDY DESIGN

Case series with chart review.

SETTING

Patients undergoing stage 1 microtia reconstruction at a tertiary pediatric hospital.

METHODS

Data collected included demographics, opioid amounts, Wong-Baker FACES Pain Rating Scale scores, opioid-related side effects, and hospital length of stay. We used generalized estimating equations to examine the effect of erector spinae block use on total opioid use and pain scores and a linear regression model to assess the effect on hospital stay.

RESULTS

Forty-seven patients were included: 14 in the erector spinae block group and 33 in the continuous wound pump group. The mean age was 8.3 years (SD, 2; range, 6-13), and 13 (32%) were female. Patients in the erector spinae block group had a 65.44% decrease in adjusted total opioid use (95% CI, -79.72% to -41.10%; P < .0001), a decrease in length of hospital stay (β = -1.69 [95% CI, -2.11 to -1.26], P < .0001), and no difference in reported pain scores when compared with patients in the continuous wound pump group.

CONCLUSIONS

This study demonstrates that early experience with an erector spinae block resulted in decreased opioid use and shorter hospital stay as compared with continuous wound infiltration with local anesthetic.

Intranasal dexmedetomidine for attenuation of hemodynamic response to laryngoscopy and intubation in adults

Background : To evaluate effectiveness of intranasal dexmedetomidine for attenuation of hemo-dynamic response to laryngoscopy and intubation in adults. Design and setting : This prospective randomized study included 90 American Society of Anesthesiologists (ASA) status I, adult patients of either sex, aged between 18-60 years, and undergoing elective surgery under general anesthesia requiring endotracheal intubation. Methods : Patients were randomly assigned to one of three groups of 30 each, to receive either intranasal saline (Group C), intranasal dexmedetomidine 1µg/kg (Group D 1 ) or intranasal dexmedetomidine 2µg/kg (Group D 2) , administered 30 minutes before the induction of anesthesia. Anesthesia technique was standardized for all patients taking part in the study. Main outcome measures : Primary outcome studied was attenuation of hemodynamic response to laryngoscopy and intubation. Secondary parameters studied were sedation score and dose of propofol required at induction. Results : There was a statistically significant rise in heart rate and systolic, diastolic and mean arterial pressures at 1, 3, and 5 minutes of intubation in group C as compared to groups D 1 and D 2 . Sedation score was significantly higher in groups D 1 and D 2 (p<0.0001). Propofol requirement was significantly lower in groups D 1 and D 2 (p<0.0001). Intranasal dexmedetomidine 2µg/kg was associated with higher a incidence of bradycardia. Conclusion : Intranasal dexmedetomidine (1µg/kg and 2µg/kg) effectively diminishes hemodynamic changes associated with laryngoscopy and intubation in adult patients undergoing elective surgery. Intranasal dex-medetomidine 2µg/kg is associated with significant bradycardia. Intranasal dexmedetomidine also provides effective preoperative sedation and decreases the dose of propofol required for induction of anesthesia.

Trends in Operative Complex Middle and Upper Maxillofacial Trauma: A 17-Year Study

OBJECTIVES/HYPOTHESIS

Over 3 million incidents of facial trauma occur each year in the United States. This study aims to determine trends in operative middle and upper maxillofacial trauma in one of the largest US cities.

STUDY DESIGN

Retrospective case-control study.

METHODS

Retrospective chart review of all operative middle and upper maxillofacial trauma from July 1993 to July 2010 presenting to Los Angeles County Hospital, a Level I Trauma Center. Data included demographics, mechanism of injury, and fracture characteristics.

RESULTS

Analysis was performed for a total of 4,299 patients and 5,549 facial fractures. Mean patient age was 34.6, and most patients were male (88%). Between the two time periods (1993-2001 and 2002-2010), there was a 42% reduction in operative maxillofacial trauma (3,510 to 2,039). Orbital floor and zygomaticomaxillary complex fractures were the most prevalent types of fractures. Panfacial fractures demonstrated the largest reduction in number of fractures (325 to 5, P<0.01). Assault and motor vehicle accidents (MVA) were the two most common mechanisms of injury. Operative fractures due to MVAs decreased (390 to 214, P = .74), whereas fractures due to assault increased (749 to 800, P<0.01). Compared to adults, pediatric facial trauma (age < 18) were caused by a higher percentage of MVAs (27% vs. 13%), auto versus pedestrian (9% vs. 5%), and gunshot wounds (8% vs. 4%) (P<0.01).

CONCLUSIONS

Operative middle and upper maxillofacial trauma decreased over a 17-year period. Assault was the most significant mechanism of trauma overall. These trends suggest that focusing future prevention strategies on curtailing interpersonal violence may more effectively address the burden of facial trauma.

LEVEL OF EVIDENCE

3 Laryngoscope, 131:1985-1989, 2021.

ERAS for Head and Neck Tissue Transfer Reduces Opioid Usage, Peak Pain Scores, and Blood Utilization

OBJECTIVES

We implement a novel enhanced recovery after surgery (ERAS) protocol with pre-operative non-opioid loading, total intravenous anesthesia, multimodal peri-operative analgesia, and restricted red blood cell (pRBC) transfusions. 1) Compare differences in mean postoperative peak pain scores, opioid usage, and pRBC transfusions. 2) Examine changes in overall length of stay (LOS), intensive care unit LOS, complications, and 30-day readmissions.

METHODS

Retrospective cohort study comparing 132 ERAS vs. 66 non-ERAS patients after HNC tissue transfer reconstruction. Data was collected in a double-blind fashion by two teams.

RESULTS

Mean postoperative peak pain scores were lower in the ERAS group up to postoperative day (POD) 2. POD0: 4.6 ± 3.6 vs. 6.5 ± 3.5; P = .004) (POD1: 5.2 ± 3.5 vs. 7.3 ± 2.3; P = .002) (POD2: 4.1 ± 3.5 vs. 6.6 ± 2.8; P = .000). Opioid utilization, converted into morphine milligram equivalents, was decreased in the ERAS group (POD0: 6.0 ± 9.8 vs. 10.3 ± 10.8; P = .010) (POD1: 14.1 ± 22.1 vs. 34.2 ± 23.2; P = .000) (POD2: 11.4 ± 19.7 vs. 37.6 ± 31.7; P = .000) (POD3: 13.7 ± 20.5 vs. 37.9 ± 42.3; P = .000) (POD4: 11.7 ± 17.9 vs. 36.2 ± 39.2; P = .000) (POD5: 10.3 ± 17.9 vs. 35.4 ± 45.6; P = .000). Mean pRBC transfusion rate was lower in ERAS patients (2.1 vs. 3.1 units, P = .017). There were no differences between ERAS and non-ERAS patients in hospital LOS, ICU LOS, complication rates, and 30-day readmissions.

CONCLUSION

Our ERAS pathway reduced postoperative pain, opioid usage, and pRBC transfusions after HNC reconstruction. These benefits were obtained without an increase in hospital or ICU LOS, complications, or readmission rates.

LEVEL OF EVIDENCE

3 Laryngoscope, 131:E792-E799, 2021.

Enhanced Recovery After Surgery-Based Perioperative Protocol for Head and Neck Free Flap Reconstruction

Objectives

Evaluate an enhanced recovery after surgery (ERAS)–based free flap management protocol implemented at our center.

Study Design

Prospective cohort study of patients after implementation of an ERAS-based perioperative care protocol for patients undergoing free flap reconstruction of the head and neck as compared with a historical control group.

Setting

Tertiary care academic medical center.

Participants and Methods

All patients undergoing free flap reconstruction were prospectively enrolled in the ERAS protocol group. A retrospective control group was identified by randomly selecting an equivalent number of patients from a records search of those undergoing free flap surgery between 2009 and 2015. Blood transfusion, complications, 30-day readmission rates, intensive care unit (ICU) and hospital length of stay, and costs of hospitalization were compared.

Results

Sixty-one patients were included in each group. Patients in the ERAS group underwent less frequent flap monitoring by physicians and had lower rates of intraoperative (70.5% vs 86.8%, P = .04) and postoperative (49.2% vs 27.2%, P = .026) blood transfusion, were more likely to be off vasopressors (98.3% vs 50.8%, P < .01) and ventilator support (63.9% vs 9.8%, P < .01) at the conclusion of surgery, and had shorter ICU stays (2.11 vs 3.39 days, P = .017). Length of stay, readmissions, and complication rates did not significantly differ between groups.

Conclusion

ERAS-based perioperative practices for head and neck free flap reconstruction can reduce time on the ventilator and in the ICU and the need for vasopressors, blood transfusions, and labor-intensive flap monitoring, without adverse effects on outcomes.

Physiology and Medical Treatments for Alopecia

Androgenetic alopecia (AGA) is the most common hair loss disorder in men and women. The characteristic and reproducible balding pattern in AGA negatively affects self-image and the external perceptions of the balding patient. The phenotypical changes are driven by dihydrotestosterone (DHT) and its precursor testosterone. DHT induces follicle miniaturization and hair cycle changes until resulting hairs no longer extrude through the skin surface. AGA is inherited in a polygenetic pattern and is susceptible to epigenetic and environmental factors. Currently, minoxidil, finasteride, and photolaser therapy are the only Food and Drug Administration-approved medical treatments for AGA.

Emerging Trends in Nasal Surgery: What Is the Impact of a Bioabsorbable Nasal Implant?

BACKGROUND

A bioabsorbable nasal valve implant (NVI) was introduced in 2016 as a minimally invasive solution to nasal valve collapse. Historically the introduction of less invasive procedures performable in-office has resulted in an increase in volume. Our objective is to evaluate this trend as it relates to nasal vestibular repair, and its impact on healthcare utilization.

METHODS

We interrogated the Medicare Part B national database for nasal vestibular repair (CPT code: 30465), Unlisted nasal procedure (30999) and septoplasty (30520) from 2010 to 2017. Septoplasty was used as a surrogate for overall nasal procedural rate. Linear regression modeling was used to examine the changes in reported vestibular repair rate adjusting for septoplasty rate.

RESULTS

In the Medicare population, the rate of septoplasty was stable from 2010 to 2017, increasing from 26,962 to 30,194 at an annual rate of 1.5%. Coding for unlisted nasal procedure increased from 272 to 333 at an adjusted annual rate of 1.1% over this time period. Coding for nasal vestibular repair increased from 2026 to 5331 over this interval at an adjusted annual rate of 0.9% from 2010 to 2016 but significantly increased to 5% between 2016 to 2017 (P < .0001).

CONCLUSION

The reported volume of nasal vestibular repair increased significantly in the year following Food and Drug Administration approval of NVIs. In the absence of a corresponding increase in septoplasty, this temporal relationship suggests that the introduction of NVIs impacted the utilization of this procedural code.

LEVEL OF EVIDENCE

N/A Laryngoscope, 2020.

A descriptive study of mental health and wellbeing of doctors and medical students in the UK

Doctors and medical students are working in a system which is affecting their mental wellbeing and their ability to provide the best possible care for patients. The British Medical Association conducted an online survey of doctors and medical students in October 2018. In total, 4347 responses were received and analysed. Doctors working the longest hours appear to be most vulnerable to psychological and emotional disturbance. Older and more senior doctors are most likely to report that their working environment has impacted on their condition. Medical students and junior doctors report the highest rate of having a formally diagnosed mental health condition in the last 12 months. This may be because they are in the vulnerable age group when psychiatric disorders start. Junior doctors were least likely to be aware of how to access help or support. Older doctors, those working as SAS (Staff, Associate Specialists and Specialty) doctors and overseas qualified doctors are most likely to say they have asked for support in managing a problem from their employer but that no support was provided. It is important to recognize that doctors, in spite of stress and poor wellbeing, continue to work hard, which has both advantages and disadvantages. These findings highlight that the environment in which doctors work, train, and study affects their mental health, and for this reason careful consideration needs to be given to the type and level of support provision available to them, as well as the ease of access and awareness of such support.

Analysis of the operative utilization of concurrent rhinoplasty and endoscopic sinus surgery

OBJECTIVES/HYPOTHESIS

To quantify and analyze the concurrent performance of rhinoplasty (RP) (with or without septoplasty) and functional endoscopic sinus surgery (FESS).

STUDY DESIGN

Cross-sectional analysis.

METHODS

Current Procedural Terminology codes were used to extract cases of RP (n = 22,360), FESS (n = 99,173), and concurrent RP with FESS (RP + FESS) (n = 1,321) within the State Ambulatory Surgery Databases of California, Florida, Maryland, and New York from 2009 to 2011. Patient demographics, surgeon volume, charge, concurrent nasal procedures, and operating room (OR) time were compared.

RESULTS

Among the 1,321 RP + FESS combination cases, a majority involved primary rhinoplasty (n = 697, 52.8%), followed by nasal valve repair (n = 563, 42.6%) and revision rhinoplasty (n = 61, 4.6%). High-volume (n > 30), medium-volume (n = 10-30), and low-volume rhinoplasty surgeons (n ≤ 9) were observed to perform a similar number of FESS + RP combination surgeries (153, 152, and 155, respectively). A majority of RP + FESS involved two or fewer sinuses (65%). Mean OR time for RP + FESS was 189.4 ± 4.2 minutes, approximately 50 minutes shorter than the sum of standalone RP performed individually (138.8 ± 1.0 minutes) and standalone FESS (102.9 ± 0.4 minutes).

CONCLUSIONS

RP + FESS more frequently involved fewer sinuses (compared with FESS alone) and was also less likely to involve revision rhinoplasty (compared with rhinoplasty alone); therefore, these cases may be selected for lower sinus disease burden and less complex rhinoplasty compared to standalone procedures. Procedures combining rhinoplasty and sinus surgery had a reduction in OR time compared to the hypothetical sum of two standalone procedures.

LEVEL OF EVIDENCE

NA Laryngoscope, 130:E311-E319, 2020.

Platelet-Rich Plasma for the Aesthetic Surgeon

Platelet-rich plasma (PRP) is an autogenously harvested blood plasma containing concentrated levels of platelets and growth factors. PRP has been identified as a promising treatment for enhancing wound healing and has been used for decades in multiple medical specialties including cardiac surgery, oral surgery, ophthalmology, and orthopedic surgery. Growing evidence for multiple aesthetic surgery applications has recently been developed, particularly for hair restoration and skin rejuvenation. The goal of this article is to review the current medical literature on PRP and identify promising applications that may be integrated into a modern aesthetic surgery practice. The evidence for the use of PRP technology is rapidly expanding as a powerful therapy for select cosmetic surgery patients.

Transposition of the Intratemporal Facial to Hypoglossal Nerve for Reanimation of the Paralyzed Face: The VII to XII TranspositionTechnique

IMPORTANCE

The hypoglossal nerve has long been an axonal source for reinnervation of the paralyzed face. In this study, we report our experience with transposition of the intratemporal facial nerve to the hypoglossal nerve for facial reanimation.

OBJECTIVES

To determine the feasibility and outcomes of the transposition of the infratemeporal facial nerve for end-to-side coaptation to the hypoglossal nerve for facial reanimation.

DESIGN, SETTINGS, AND PARTICIPANTS

A case series of 20 patients with facial paralysis who underwent mobilization and transposition of the intratemporal segment of the facial nerve for an end-to-side coaptation to the hypoglossal nerve (the VII to XII technique). Participants were treated between January 2007 and December 2014 at a tertiary care center.

MAIN OUTCOMES AND MEASURES

Outcome measures include paralysis duration, facial tone, facial symmetry at rest, and with smile, oral commissure excursion, post-reanimation volitional smile, and synkinesis.

METHODS

Demographic data, the effects of this technique on facial tone, symmetry, oral commissure excursion and smile recovery were evaluated. Preoperative and postoperative photography and videography were reviewed. Facial symmetry was assessed with a facial asymmetry index. Smile outcomes were evaluated with a visual smile recovery scale, and lip excursion was assessed with the MEEI-SMILE system.

RESULTS

All 20 patients had adequate length of facial nerve mobilized for direct end-to-side coaptation to the hypoglossal nerve. The median duration of facial paralysis prior to treatment was 11.4 months. Median follow-up time was 29 months. Three patients were excluded from functional analysis due to lack of follow-up. Facial symmetry at rest and during animation improved in 16 of 17 patients. The median (range) time for return of facial muscle tone was 7.3 (2.0-12.0) months. A significant reduction in facial asymmetry index occurred at rest and with movement. The MEEI FACE-gram software detected a significant increase in horizontal, vertical, overall lip excursion and smile angle. No patient developed significant tongue atrophy, impaired tongue mobility, or speech or swallow dysfunction.

CONCLUSIONS AND RELEVENCE

Mobilization of the intratemporal segment of the facial nerve provides adequate length for direct end-to-end coaptation to the hypoglossal nerve and is effective in restoring facial tone and symmetry after facial paralysis. The resulting smile is symmetric or nearly symmetric in the majority of patients with varying degree of dental show. The additional length provided by utilizing the intratemporal segment of the facial nerve reduces the deficits associated with complete hypoglossal division/splitting, and avoids the need for interposition grafts and multiple coaptation sites.

LEVEL OF EVIDENCE

4.

White adipose tissue inflammation and cancer-specific survival in patients with squamous cell carcinoma of the oral tongue

BACKGROUND

Obesity is associated with increased adipose tissue in the tongue. Chronic white adipose tissue (WAT) inflammation commonly occurs in the obese. We investigated whether WAT inflammation in the tongue impacts survival in patients with squamous cell carcinoma (SCC) of the oral tongue.

METHODS

In a retrospective cohort study, patients with T1 and T2 SCC of the oral tongue who underwent curative-intent resection were included. Tongue WAT inflammation was defined by the presence of dead or dying adipocytes surrounded by macrophages forming crown-like structures. The primary and secondary endpoints were disease-specific survival (DSS) and overall survival (OS), respectively. Subgroup analyses were carried out in patients without lymph node involvement for whom adjuvant therapies were not indicated.

RESULTS

Archived tissue was available from 125 patients. The median follow-up was 55 months (range, 3-156 months). Overall, 49 of 125 patients (39%) had tongue WAT inflammation, which was associated with higher body mass index, increased tumor thickness, and vascular invasion (P < .05). The 3-year DSS rate for patients with tongue WAT inflammation was 59% (95% confidence interval [CI], 46%-76%) versus 82% (95% CI, 73%-92%) for those without inflammation. For patients without lymph node involvement for whom adjuvant therapy was not indicated (N = 70), tongue WAT inflammation was associated with shortened DSS and OS (P < .05). When adjusted for body mass index and potential prognostic covariates, the hazard ratio for DSS and OS was 5.40 (95% CI, 1.20-24.26) and 2.97 (95% CI, 1.02-8.65), respectively.

CONCLUSIONS

Tongue WAT inflammation is associated with worse DSS and OS in patients who have early stage SCC of the oral tongue. Cancer 2016;122:3794-3802. © 2016 American Cancer Society.

A comparison of the rheologic properties of an adipose-derived extracellular matrix biomaterial, lipoaspirate, calcium hydroxylapatite, and cross-linked hyaluronic acid

IMPORTANCE

Acquired soft-tissue injury with resultant volume loss may cause significant deformity in size, shape, and body or facial contour. Current autologous fat transfer techniques have several limitations, including availability, donor site morbidity, and unpredictable rates of resorption. We present an extracellular matrix (ECM) biomaterial derived from human adipose tissue as an off-the-shelf alternative for soft-tissue volume restoration and compare clinically relevant rheologic properties.

OBJECTIVES

To determine the rheologic properties of adipose-derived ECM and to compare it with lipoaspirate, calcium hydroxylapatite, and cross-linked hyaluronic acid.

DESIGN, SETTING, AND PARTICIPANTS

Adipose-derived ECM (n = 4), lipoaspirate acquired from aesthetic liposuction (n = 4), calcium hydroxylapatite (n = 4), and cross-linked hyaluronic acid (n = 4) were obtained to determine the viscoelastic properties.

INTERVENTIONS

Dynamic frequency oscillation measurements were conducted using a rheometer (ARES-G2; TA Instruments). All injections were performed using a 20-gauge needle, and all measurements were performed using serrated 25-mm parallel-plate geometry with a 1.0-mm gap at 37°C.

MAIN OUTCOMES AND MEASURES

Oscillation measurements for storage modulus, a measure of the elastic properties, and complex viscosity were obtained over an angular frequency range of 0.01 to 100 rad/s.

RESULTS

At 1 Hz, adipose-derived ECM had a mean (SD) storage modulus of 713.2 (42.9) Pa and a mean (SD) complex viscosity of 115.8 (6.9) Pa/s. Lipoaspirate had a mean (SD) storage modulus of 382.1 (66.8) Pa and a mean (SD) complex viscosity of 61.5 (10.7) Pa/s. Calcium hydroxylapatite had a mean (SD) storage modulus of 1122.1 (67.1) Pa and a mean (SD) complex viscosity of 207.2 (11.6) Pa/s. Cross-linked hyaluronic acid had a mean (SD) storage modulus of 63.9 (3.0) Pa and a mean (SD) complex viscosity of 10.9 (0.5) Pa/s.

CONCLUSIONS AND RELEVANCE

Of the 4 materials tested, calcium hydroxylapatite has the highest mean storage modulus and mean complex viscosity, and hyaluronic acid has the lowest. The viscoelastic properties of adipose-derived ECM are most similar to those of lipoaspirate, suggesting that it may be an ideal candidate for soft-tissue reconstruction.

Tobacco smoke-induced immunologic changes may contribute to oral carcinogenesis

OBJECTIVE

The objective of this study was to determine if tobacco smoke (TS), a risk factor for cancers of the aerodigestive tract, may contribute to oral carcinogenesis, in part, by suppressing local immunity.

METHODS

Mice were placed in Plexiglas holders in which they breathed TS through the nose and mouth for 1 hour daily for 21 days. Control mice breathed room air in the same manner. One day after the last exposure, mice were immunized by application of oxazolone to each buccal mucosa. Control mice were mock immunized by application of vehicle alone. Five days later, all mice were challenged on the ears with oxazolone, and 24-hour ear swelling assessed as contact hypersensitivity.

RESULTS

Mice exposed to TS had a significantly smaller contact hypersensitivity response compared with controls. When subsequently reimmunized on the glabrous skin, mice originally primed through TS-exposed mucosa could not be fully immunized, indicating induction of immunologic tolerance by exposure to hapten through TS-perturbed mucosa. Immunocompetent mice exposed to TS in this manner and challenged by submucosal placement of a syngeneic malignant tumor had significantly increased tumor growth over time compared with controls. No difference in growth rate was observed when the experiment was performed with natural killer cell-deficient, SCID (severe combined immunodeficiency) mice. In addition, exposure of epidermal Langerhans cells in vitro to an aqueous extract of TS impaired their ability to undergo maturation and to present antigen to responsive T cells.

CONCLUSIONS

Immunologic changes induced in the oral cavity by exposure to TS may play a role in the development of oral cancers.

p53 modulates Hsp90 ATPase activity and regulates aryl hydrocarbon receptor signaling

The aryl hydrocarbon receptor (AhR), a client protein of heat shock protein 90 (Hsp90), is a ligand-activated transcription factor that plays a role in polycyclic aromatic hydrocarbon (PAH)-induced carcinogenesis. Tobacco smoke activates AhR signaling leading to increased transcription of CYP1A1 and CYP1B1, which encode proteins that convert PAHs to mutagens. Recently, p53 was found to regulate Hsp90 ATPase activity via effects on activator of Hsp90 ATPase (Aha1). It is possible, therefore, that AhR-dependent expression of CYP1A1 and CYP1B1 might be affected by p53 status. The main objective of this study was to determine whether p53 modulated AhR-dependent gene expression and PAH metabolism. Here, we show that silencing p53 led to elevated Aha1 levels, increased Hsp90 ATPase activity, and enhanced CYP1A1 and CYP1B1 expression. Overexpression of wild-type p53 suppressed levels of CYP1A1 and CYP1B1. The significance of Aha1 in mediating these p53-dependent effects was determined. Silencing of Aha1 led to reduced Hsp90 ATPase activity and downregulation of CYP1A1 and CYP1B1. In contrast, overexpressing Aha1 was associated with increased Hsp90 ATPase activity and elevated levels of CYP1A1 and CYP1B1. Using p53 heterozygous mutant epithelial cells from patients with Li-Fraumeni syndrome, we show that monoallelic mutation of p53 was associated with elevated levels of CYP1A1 and CYP1B1 under both basal conditions and following treatment with benzo[a]pyrene. Treatment with CP-31398, a p53 rescue compound, suppressed benzo[a]pyrene-mediated induction of CYP1A1 and CYP1B1 and the formation of DNA adducts. Collectively, our results suggest that p53 affects AhR-dependent gene expression, PAH metabolism, and possibly carcinogenesis.

Tobacco smoke-induced immunologic changes may contribute to oral carcinogenesis

OBJECTIVE

The objective of this study was to determine if tobacco smoke (TS), a risk factor for cancers of the aerodigestive tract, may contribute to oral carcinogenesis, in part, by suppressing local immunity.

METHODS

Mice were placed in Plexiglas holders in which they breathed TS through the nose and mouth for 1 hour daily for 21 days. Control mice breathed room air in the same manner. One day after the last exposure, mice were immunized by application of oxazolone to each buccal mucosa. Control mice were mock immunized by application of vehicle alone. Five days later, all mice were challenged on the ears with oxazolone, and 24-hour ear swelling assessed as contact hypersensitivity.

RESULTS

Mice exposed to TS had a significantly smaller contact hypersensitivity response compared with controls. When subsequently reimmunized on the glabrous skin, mice originally primed through TS-exposed mucosa could not be fully immunized, indicating induction of immunologic tolerance by exposure to hapten through TS-perturbed mucosa. Immunocompetent mice exposed to TS in this manner and challenged by submucosal placement of a syngeneic malignant tumor had significantly increased tumor growth over time compared with controls. No difference in growth rate was observed when the experiment was performed with natural killer cell-deficient, SCID (severe combined immunodeficiency) mice. In addition, exposure of epidermal Langerhans cells in vitro to an aqueous extract of TS impaired their ability to undergo maturation and to present antigen to responsive T cells.

CONCLUSIONS

Immunologic changes induced in the oral cavity by exposure to TS may play a role in the development of oral cancers.

Impact of obesity on the survival of patients with early-stage squamous cell carcinoma of the oral tongue

BACKGROUND

Although obesity increases risk and negatively affects survival for many malignancies, the prognostic implications in squamous cell carcinoma (SCC) of the oral tongue, a disease often associated with prediagnosis weight loss, are unknown.

METHODS

Patients with T1-T2 oral tongue SCC underwent curative-intent resection in this single-institution study. All patients underwent nutritional assessment prior to surgery. Body mass index (BMI) was calculated from measured height and weight and categorized as obese (≥ 30 kg/m(2) ), overweight (25-29.9 kg/m(2) ), or normal (18.5-24.9 kg/m(2) ). Clinical outcomes, including disease-specific survival, recurrence-free survival, and overall survival, were compared by BMI group using Cox regression.

RESULTS

From 2000 to 2009, 155 patients (90 men, 65 women) of median age 57 years (range, 18-86 years) were included. Baseline characteristics were similar by BMI group. Obesity was significantly associated with adverse disease-specific survival compared with normal weight in univariable (hazard ratio [HR] = 2.65, 95% confidence interval [CI] = 1.07-6.59; P = .04) and multivariable analyses (HR = 5.01; 95% CI = 1.69-14.81; P = .004). A consistent association was seen between obesity and worse recurrence-free survival (HR = 1.87; 95% CI = 0.90-3.88) and between obesity and worse overall survival (HR = 2.03; 95% CI = 0.88-4.65) though without reaching statistical significance (P = .09 and P = .10, respectively) in multivariable analyses.

CONCLUSIONS

In this retrospective study, obesity was an adverse independent prognostic variable. This association may not have been previously appreciated due to confounding by multiple factors including prediagnosis weight loss.

Hospital-acquired conditions in head and neck cancer surgery

OBJECTIVES/HYPOTHESIS

The Centers for Medicare and Medicaid Services has identified 10 hospital-acquired conditions (HACs) for which they will not reimburse care. We sought to determine the incidence of HACs in head and neck cancer (HNCA) surgery and the association with in-hospital mortality, complications, length of hospitalization, and costs.

STUDY DESIGN

Retrospective cross-sectional study.

METHODS

Discharge data from the Nationwide Inpatient Sample for 123,662 patients who underwent an ablative procedure for a malignant oral cavity, laryngeal, hypopharyngeal, or oropharyngeal neoplasm during 2001-2008 were analyzed using cross-tabulations and multivariate regression modeling.

RESULTS

HACs occurred in <1% of cases, with vascular catheter-associated infection comprising >70% of all HACs. The occurrence of HACs was significantly associated with urgent or emergent admission (odds ratio [OR]=2.0, P=.004), major surgical procedures (OR=2.3, P<.001), flap reconstruction (OR=3.5, P<.001), and advanced comorbidity (OR=2.0, P<.001). There was no association between HACs and hospital size, location, ownership, volume status, or safety-net burden. HACs were significantly associated with in-hospital mortality (OR=3.8, P=.001), surgical complications (OR=4.9, P<.001), and medical complications (OR=5.6, P<.001). After controlling for all other variables, HACs were associated with significantly increased length of hospitalization and hospital-related costs, with vascular catheter-associated infection and foreign object after surgery associated with the greatest increase in length of stay and costs.

CONCLUSIONS

HACs are uncommon events in HNCA surgical patients. Because prediction of HACs is poor and the potential for human error crosses demographic, geographic, and structural boundaries, universal innovative measures to reduce the occurrence of HACs are needed.

Impact of obesity on survival in patients (pts) with early-stage squamous cell carcinoma (SCC) of the oral tongue

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Background: Obesity is a risk factor for several malignancies and an independent predictor of worse outcomes. In contrast, low body mass index (BMI) has been associated with increased risk of oropharyngeal cancers and poorer prognosis. In tongue SCC, impaired nutrition, smoking, and alcohol use impact BMI, and pre-diagnosis weight (wgt) loss negatively affects survival. The prognostic effect of obesity in tongue cancer is unknown. Methods: We conducted a single-institution, retrospective study of pts who underwent resection of T1/T2 SCC of the oral tongue. All pts underwent nutritional assessment prior to surgery. BMI was calculated from measured height and wgt at surgery and categorized as obese (≥30), overwgt (25-29.9), or normal (18.5-24.9). The association between BMI and the primary endpoint, disease specific survival (DSS), was evaluated by Cox regression. The effect of BMI on the secondary endpoints, recurrence free survival (RFS) and overall survival (OS), was also assessed. Results: From 2000 to 2005, 155 pts (90 men, 65 women) of median age 57 (range 18-86) were included. Clinicopathologic characteristics were similar by BMI group. Obesity was significantly associated with adverse DSS compared with normal wgt in univariable (Table) and multivariable analyses (HR 2.87; 95% CI, 1.08-7.67; p=0.04). Obesity was also significantly associated with adverse RFS (HR 2.53; 95% CI, 1.12-5.74; p=0.03). Overwgt subjects may also have worse RFS (HR 1.74; 95% CI, 0.85-3.55; p=0.13). In pts without pre-diagnosis wgt loss (n=94), obesity was significantly associated with adverse OS (HR 2.70; 95% CI, 1.12-6.54; p=0.03). Conclusions: These data suggest that obesity is associated with a worse prognosis in tongue cancer, which may not have previously been appreciated due to confounding by pre-diagnosis wgt loss. [Table: see text]

Carnosol, a constituent of Zyflamend, inhibits aryl hydrocarbon receptor-mediated activation of CYP1A1 and CYP1B1 transcription and mutagenesis

The aryl hydrocarbon receptor (AhR), a ligand-activated member of the basic helix-loop-helix family of transcription factors, plays a significant role in polycyclic aromatic hydrocarbon (PAH)-induced carcinogenesis. In the upper aerodigestive tract of humans, tobacco smoke, a source of PAHs, activates the AhR leading to increased expression of CYP1A1 and CYP1B1, which encode proteins that convert PAHs to genotoxic metabolites. Inhibitors of Hsp90 ATPase cause a rapid decrease in levels of AhR, an Hsp90 client protein, and thereby block PAH-mediated induction of CYP1A1 and CYP1B1. The main objective of this study was to determine whether Zyflamend, a polyherbal preparation, suppressed PAH-mediated induction of CYP1A1 and CYP1B1 and inhibited DNA adduct formation and mutagenesis. We also investigated whether carnosol, one of multiple phenolic antioxidants in Zyflamend, had similar inhibitory effects. Treatment of cell lines derived from oral leukoplakia (MSK-Leuk1) and skin (HaCaT) with benzo[a]pyrene (B[a]P), a prototypic PAH, induced CYP1A1 and CYP1B1 transcription, resulting in enhanced levels of message and protein. Both Zyflamend and carnosol suppressed these effects of B[a]P. Notably, both Zyflamend and carnosol inhibited Hsp90 ATPase activity and caused a rapid reduction in AhR levels. The formation of B[a]P-induced DNA adducts and mutagenesis was also inhibited by Zyflamend and carnosol. Collectively, these results show that Zyflamend and carnosol inhibit Hsp90 ATPase leading to reduced levels of AhR, suppression of B[a]P-mediated induction of CYP1A1 and CYP1B1, and inhibition of mutagenesis. Carnosol-mediated inhibition of Hsp90 ATPase activity can help explain the chemopreventive activity of herbs such as Rosemary, which contain this phenolic antioxidant.

Imaging correlation of children with DFNB1 vs non-DFNB1 hearing loss

OBJECTIVES

To evaluate temporal bone CT findings in GJB2-related deafness (DFNB1) hearing loss and non-DFNB1 hearing loss children.

STUDY DESIGN

Case-control series.

SUBJECTS AND METHODS

Children with nonsyndromic hearing loss diagnosed as DFNB1 or non-DFNB1 after screening GJB2 allele variants and the large GJB6 deletion. Temporal bone CT images compared in a cohort of nine DFNB1 children with 10 non-DFNB1 children. Visual criteria and absolute measurements were compared against established normative values.

RESULTS

Visual inspection failed to identify two patients with abnormalities identified by using absolute measurements. Only one of nine DFNB1 children had an ear anomaly versus seven of 10 non-DFNB1 (odds ratio 16.33; 95% CI, 1.35, 197.78; P = 0.050). The non-DFNB1 group had a mean vestibule width that was significantly larger, and a mean lateral semicircular canal island width and vestibular aqueduct that were significantly smaller than the DFNB1 group.

CONCLUSIONS

Visual inspection of temporal bone CT images alone may not identify all anomalies and should be used with absolute CT measurements. Abnormal temporal bone CT findings are significantly less likely in children with DFNB1 compared with non-DFNB1 children despite similar age and degree of hearing loss.

SIX1 mutation screening in 247 branchio-oto-renal syndrome families: a recurrent missense mutation associated with BOR

Branchio-oto-renal syndrome (BOR) is a clinically heterogeneous autosomal dominant form of syndromic hearing loss characterized by variable hearing impairment, malformations of the pinnae, the presence of branchial arch remnants, and various renal abnormalities. Both EYA1 and SIX1 are expressed in developing otic, branchial and renal tissue. Consistent with this expression pattern, mutations in both genes cause BOR syndrome. Mutations in EYA1 are found in approximately 40% of patients with the BOR phenotype, however, the role of SIX1 is much lower. To date only three different SIX1 mutations have been described in BOR patients. The current screen of 247 BOR families detected five novel SIX1 mutations (c.50T>A, c.218A>C, c.317T>G, c.329G>A, c.334C>T) and one previously reported mutation (c.328C>T) seen in 5 unrelated families. All mutations are within the protein-binding Six domain. Phenotypic variability was high in these BOR families. Seven of the eight known SIX1 mutations are missense and the one in frame deletion is predicted to be functionally similar. The wide phenotypic variability precludes making genotype-phenotype correlations at this time.

Branchio-oto-renal syndrome

Branchio-oto-renal syndrome, a phenotype consisting of hearing loss, auricular malformations, branchial arch remnants, and renal anomalies is now recognized as one of the more common forms of autosomal dominant syndromic hearing impairment. Three loci known to be associated with the BOR phenotype have been identified and two genes that act in a regulatory network have been cloned, EYA1 and SIX1. EYA1 and SIX1 are homologous to genes involved in Drosophila eye development, eyes absent gene (eya), and sine oculis (so), respectively. EYA1, a transcriptional co-activator has a conserved, 271-amino acid, C-terminal known as the Eya Domain (ED). SIX1 has two highly conserved domains; a homeodomain (HD) and a specific Six-domain (SD) whose products function as transcription factors with specific DNA-binding activity that are crucial for protein-protein interaction. To determine the molecular basis for the organ defects that occur in BOR syndrome, many studies have focused on the effects of mutations to EYA and effects of mutations of the EYA-SIX regulatory system. However, over 60% of BOR syndrome patients do not have known mutations in EYA1 and relatively little is known about mutations to SIX1. Further evaluation of SIX1 and its related target genes may provide a better understanding of the pathophysiology of BOR syndrome and offer greater clues to the disease mechanisms.

Clinical aspects of hereditary hearing loss

Hearing loss is an etiologically diverse condition with many disease-related complications and major clinical, social, and quality of life implications. As the rate of acquired hearing loss secondary to environmental causes decreases and improvements in the diagnosis of abnormalities occur, the significance of genetic factors that lead to deafness increases. Advancements in molecular biology have led to improved detection and earlier intervention in patients with hearing loss. Subsequently, earlier implementation of educational services and cochlear implant technology in patients with profound hearing loss now results in superior communication skills and enhanced language development. The aim of this review is to provide a comprehensive framework underlying the causes of hearing impairment and to detail the clinical management for patients with hereditary hearing loss.

Community pharmacists' knowledge and dispensing recommendations for treatment of acute diarrhoea in Trinidad, West Indies

Using a hypothetical case presentation of a patient with acute diarrhoea, community pharmacists in Trinidad were asked about their knowledge and dispensing recommendations to manage acute diarrhoea. Oral rehydration salts (ORS) were recommended by 86% (79), but more pharmacists would recommend ORS as the first choice therapy alone, for children (70%) than adults (33%) (p < 0.01). Antimotility agents as a first choice therapy alone or with ORS would be given to more adults (60%) than children (10%) (p < 0.01), and more adults (59%) than children (33%) would receive cotrimoxazole. Pharmacists (93%) would counsel on preparation, storage and treatment schedule for ORS, but not on discontinuing (32%) or continuing ORS (4%). Despite 51 pharmacists knowing the WHO guidelines to treat acute diarrhoea, only 23 dispensed in accordance. Educational re-enforcement to manage acute diarrhoea and dispensing practices of medications are necessary for pharmacists who are the first patient contact in Trinidad.

Nucleotide sequence of psbQ gene for 16-kDa protein of oxygen-evolving complex from Arabidopsis thaliana and regulation of its expression

The psbQ gene encoding a 16-kDa polypeptide of the oxygen-evolving complex of photosystem II has been isolated from Arabidopsis thaliana and characterized. The gene consists of a 28 nucleotide long leader sequence, two introns and three exons encoding a 223-amino-acid precursor polypeptide. The first 75 amino acids act as a transit peptide for the translocation of the polypeptide into the thylakoid lumen. Expression studies show that the gene is light-inducible and expresses only in green tissues with high steady-state mRNA levels in leaves. Using this gene as a probe, restriction fragment length polymorphism between two ecotypes, Columbia and Estland, has also been detected.

The psbO gene for 33-kDa precursor polypeptide of the oxygen-evolving complex in Arabidopsis thaliana--nucleotide sequence and control of its expression

The 33-kDa polypeptide of the oxygen-evolving complex of photosystem II is nuclear-encoded. The single psbO gene of Arabidopsis thaliana, as suggested by Southern hybridization, has been isolated from the genomic library and sequenced. The sequence analysis has revealed that the psbO gene harbors two introns and encodes a precursor polypeptide of 332 amino acid residues; the first 85 amino acid residues represent the transit peptide and the following 247 amino acids constitute the mature polypeptide. The hydrophilic nature of the 33-kDa protein is confirmed by the presence of 27% charged residues. Northern analysis of the total RNA from Arabidopsis indicates that a 1.2-kb transcript represents the psbO gene. It is expressed in a tissue-specific manner -- the steady-state transcript levels being highest in the leaves and virtually undetectable in the roots. Also, expression of the psbO gene is development-dependent and regulated by light in young Arabidopsis seedlings. In a constitutively photomorphogenic mutant of Arabidopsis, pho2 (plumular hook open 2), the psbO gene is de-repressed in young, dark-grown seedlings, resulting in increased transcript abundance compared to the wild-type. These studies, thus, define the influence of at least one regulatory component for psbO expression.

Nucleotide sequence of the psbP gene encoding precursor of 23-kDa polypeptide of oxygen-evolving complex in Arabidopsis thaliana and its expression in the wild-type and a constitutively photomorphogenic mutant

The psbP gene encoding the precursor of 23-kDa polypeptide of the oxygen-evolving complex of photosystem II has been isolated from Arabidopsis thaliana genomic library and sequenced. The gene harbors three introns and encodes a mature polypeptide of 186 amino acid residues and a transit peptide of 77 amino acid residues. The deduced molecular mass of the mature polypeptide is 23.5-kDa and it contains 22.6% charged amino acid residues which may contribute to the hydrophilic nature of the protein. The transcript encoded by psbP gene of Arabidopsis is approximately 1.3-kb long. In wild-type Arabidopsis seedlings, its expression is organ-specific and is regulated by endogenous developmental cues, light and sucrose. In a constitutively photomorphogenic mutant of Arabidopsis, designated as pho1, the psbP gene is partly derepressed in young, dark-grown seedlings, resulting in a slightly higher level of the transcript. Additionally, the pho1 mutant shows slow accumulation of psbP transcript upon illumination of young, dark-grown seedlings. However, the derepression is not markedly displayed on dark-adaptation of pho1 plants grown in continuous light. These studies, therefore, define the activity of at least one cellular effector involved in regulation of psbP expression.

Presence of growth-stimulating fibrin degradation products containing fragment E in human atherosclerotic plaques

The key event in the formation of stenosing atherosclerotic lesions is widely thought to be smooth muscle cell proliferation, but the factors primarily responsible for initiating this remain uncertain. Previously we have shown that aqueous extracts of proliferative types of human atherosclerotic plaque stimulate cell proliferation in the chick chorioallantoic membrane (CAM). This has been attributed largely to the fibrin degradation products in the extracts, components removeable by affinity chromatography. We now demonstrate that the fibrinogen content of the extract, removeable by clotting out with thrombin, also makes a contribution to the activity by forming fibrin on the surface of the CAM. Affinity chromatography experiments using anti fragment D and E antisera indicate that activity resides in the E-containing fibrin fragments, consistent with previous work with FDP prepared in vitro.

Efficacy of LY233053, a competitive glutamate antagonist, in experimental central nervous system ischemia

Antagonists of excitatory amino acids appear to serve a neuroprotective role during ischemic conditions in a variety of in vivo and in vitro models. The usefulness of such agents in the clinical setting, however, may be limited by poor central nervous system (CNS) entry and intolerable side effects. The authors report high efficacy in reducing neurological damage and relatively limited side effects of LY233053, a novel competitive glutamate antagonist, in two models of experimental CNS ischemia in the rabbit.

Effect of protein kinase C modulation on outcome of experimental CNS ischemia

Protein kinase C (PKC) is an important intracellular regulator, and its activity may play a central role in the modulation of neuronal ischemic damage. Staurosporine and the compound H-7 are potent in vitro inhibitors of PKC, and 1,2-oleoylacetylglycerol (OAG) is an effective activator. We administered these compounds through a spinal subarachnoid catheter and demonstrated in vivo alteration of spinal cord PKC activity. We then tested the effects of altering PKC activity in a well-established rabbit model of reversible spinal cord ischemia. Animals within each experimental group were subjected to a range of spinal cord ischemic durations by temporary occlusion of the infrarenal abdominal aorta. Compared to control, both staurosporine and H-7 significantly shortened the duration of ischemia that the animals could tolerate, without developing permanent paraplegia. OAG resulted in an insignificant lengthening of the ischemic duration that the animals could withstand. The worsening of ischemic outcome by PKC inhibitors suggests that the enzyme is important for maintaining neurologic function under ischemic conditions, possibly secondary to modulation of intracellular calcium levels.