Accessory submandibular duct sialolithiasis identified during sialendoscopy

We describe a unique case of a 62-year-old patient with recurrent right submandibular sialadenitis. He initially appeared to have extensive sialolithiasis of the right submandibular duct on computed tomography imaging and examination, but sialendoscopy demonstrated a normal-appearing right submandibular duct. An accessory duct posterior and parallel to the normal duct was identified at the time of sialendoscopy and was found to have extensive sialolithiasis, which required removal by both an endoscopic and intraoral technique. To the best of our knowledge, this is the first report of sialolithiasis of an accessory submandibular duct identified at the time of sialendoscopy; the other few reported cases in the literature are based primarily on findings from traditional sialography or magnetic resonance sialography. Identification of accessory salivary ducts requires intraoperative consideration of this entity during sialendoscopy. Open approaches to sialolithiasis, however, may be aided by appropriate preoperative imaging.

The effects of nasal closure on quality of life in patients with hereditary hemorrhagic telangiectasia

Introduction

Epistaxis is the most common symptom of hereditary hemorrhagic telangiectasia (HHT). Complete nasal closure is one of the treatment options for patients with severe, intractable epistaxis. In our experience, this surgery can be life changing in a positive sense; but many patients as well as their physicians understandably fear that such a procedure will diminish certain aspects of quality of life (QOL).

Methods

Case-control study of HHT patients treated at the University of Utah HHT Center of Excellence with and without nasal closure from January 2005 to January 2016. Patients were matched according to epistaxis severity. Each included patient was issued three surveys: Epistaxis Severity Score (ESS), the Pittsburg Sleep Quality Index (PSQI), and the Nasal Obstruction Symptom Evaluation (NOSE).

Results

After treatment, the mean PSQI and NOSE scores were not significantly different between the two groups. However, the mean ESS score in the nasal closure group was significantly lower at 1.10 compared to the severe epistaxis group with a mean score of 3.99 (P = .027).

Conclusion

The results of this study demonstrate that nasal closure significantly improves epistaxis severity without having a significant effect on sleep or nasal obstruction as they relate to QOL. These findings suggest that nasal closure should be considered for HHT patients with chronic severe epistaxis.

Level of Evidence

4.

An evaluation of the severity and progression of epistaxis in hereditary hemorrhagic telangiectasia 1 versus hereditary hemorrhagic telangiectasia 2

OBJECTIVES/HYPOTHESIS

Hereditary hemorrhagic telangiectasia (HHT) is an autosomal dominant vascular dysplasia whose hallmark symptom is spontaneous recurrent epistaxis. Two major genetic subtypes of this syndrome are HHT1 and HHT2. Severity of epistaxis ranges from occasional low-volume bleeding to frequent large-volume hemorrhage. This study evaluated the severity and progression of epistaxis in HHT1 versus HHT2.

STUDY DESIGN

Retrospective cohort study.

METHODS

A retrospective chart review was performed for 183 genotyped HHT patients seen at our center from 2010 to 2013. Data collected included epistaxis severity score (ESS), age of epistaxis onset, number and type of treatments, age at which treatments were sought, complete blood count values, ferritin, number of telangiectases, blood transfusions, iron therapy history, and patient demographics.

RESULTS

115 subjects with HHT2 were compared to 68 with HHT1. Subjects with HHT2 had a higher ESS compared to HHT1 (P = .043) and a later age of onset of epistaxis (P = .005). HHT2 subjects were more likely to use oral iron (P = .032) and were more likely to seek interventions to control their epistaxis (P = .029).

CONCLUSIONS

HHT2 is associated with more severe epistaxis and a subsequent higher rate of interventions, requiring more aggressive therapy as compared to HHT1.

LEVEL OF EVIDENCE

4.

Tumor Biomarkers in Spindle Cell Variant Squamous Cell Carcinoma of the Head and Neck

OBJECTIVE

To determine biomarkers of recurrence and survival in patients with spindle cell variant squamous cell carcinoma (SpSCC) of the head and neck.

STUDY DESIGN

Retrospective case control study.

SETTING

Tertiary academic center.

SUBJECTS AND METHODS

Thirty-two SpSCC patients (mean age, 68.8) between 1987 and 2009 were identified and reviewed. A tissue microarray (TMA) was constructed from tumor specimens. Tumor biomarkers under study included p16, epidermal growth factor receptor (EGFR), p53, EZH2, cyclin D1, CD104, HGFa, p21, and cMET. An additional TMA was constructed from patients with non-SpSCC oral cavity squamous cell carcinoma for comparative purposes. The main outcomes were overall survival (OS), disease-specific survival (DSS), and recurrence-free survival (RFS).

RESULTS

In the SpSCC cohort, tumors positive for cMet had worse OS (P < .001). Patients positive for cMet (P = .007), cyclin D1 (P = .019), and p16 (P = .004) had worse DSS. Recurrence-free survival was also worse in patients with tumors positive for cMet (P = .037), cyclin D1 (P = .012), and p16 (P < .001). Compared with the oral cavity cohort, there was a significantly larger proportion of patients in the SpSCC group with tumors staining positive for cMet and a lower proportion of tumors positive for cyclin D1.

CONCLUSION

cMet, cyclin D1, and p16 are predictive tumor biomarkers for risk of recurrence and worse DSS in patients with SpSCC.

Treatment of severe refractory epistaxis in hereditary hemorrhagic telangiectasia using a two-flap nasal closure method

BACKGROUND

Nasal closure has been shown to effectively manage severe epistaxis refractory to other treatments in patients with hereditary hemorrhagic telangiectasia (HHT). The nasal closure procedure may be underutilized because of its surgical complexity and flap breakdown.

METHODS

This work is a retrospective review of 13 HHT patients treated for severe epistaxis with nasal closure between 2005 and 2013. Operating room (OR) time, need for revision surgery, preprocedure, and postprocedure epistaxis severity score (ESS), complete blood count values, and Glasgow Benefit Inventory (GBI) questionnaire results were collected for each patient. The technique is described. We characterize a typical nasal closure patient and compare outcomes based on our experience with the traditional 3-flap closure and a simplified 2-flap nasal closure procedure.

RESULTS

The average candidate for nasal closure in this series had an ESS of 7.88, hemoglobin (Hgb) of 8.3 g/dL, and received multiple transfusions, iron therapy, and cautery/coagulation procedures. Average ESS subsequent to nasal closure using the 2-flap method is 0.92 and mean GBI score is 56.3. Comparison of 5 patients who underwent the traditional 3-flap nasal closure procedure and 8 patients receiving the 2-flap nasal closure showed no significant difference in postoperative ESS or GBI metrics. Mean operating room times of the traditional and simplified methods were 3.12 hours and 1.44 hours (p = 0.0001). Mean time to first revision for 8 nasal closure patients was 21.5 months.

CONCLUSION

In short-term follow-up, the 2-flap procedure showed comparable effectiveness with significantly reduced complexity and operative time compared to the traditional nasal closure method.

Complex nontuberculous mycobacterial cervicofacial lymphadenitis: What is the optimal approach?

OBJECTIVES/HYPOTHESIS

Assess the role of combined antimicrobial and surgical therapy for difficult-to-treat nontuberculous mycobacteria (NTM) lesions of the head and neck in children.

STUDY DESIGN

Retrospective cohort.

METHODS

Retrospective review of pediatric head and neck NTM lesions at a tertiary children's hospital from 1999 to 2012.

RESULTS

Seventy-one children were diagnosed with NTM lesions. Age of presentation ranged between 7 and 204 months of age. Most patients (62%) had multiple lesions. Treatments included incision and drainage, curettage, antibiotics, excision, and any combination of surgery and antibiotics. Upon initial presentation, the most common treatment was surgical excision alone (n = 34) with a high complication rate (50%). In 18 cases, patients were initially treated with a combination of antibiotics and surgical excision due to the extent or location of the lesion(s). Complication rate in these patients was also high (67%). The most common complications in surgically excised NTM lesions included temporary or persistent facial nerve dysfunction (24.6%), poor wound healing/scarring (10.8%), and Frey's syndrome (6.2%).

CONCLUSIONS

Surgical excision with or without medical therapy for NTM cervicofacial lymphadenitis in high-risk regions commonly resulted in marginal mandibular nerve dysfunction (24.6%). Postoperative facial nerve weakness generally resolved within a year. High rates of complications and a lack of proven best approaches suggest tailoring the approach to address the potential risks in that particular patient based on location and severity.

LEVEL OF EVIDENCE

4 Laryngoscope, 126:1677-1680, 2016.

Diagnosis of asthma: clinical assessment

BACKGROUND

Asthma is a common condition that presents with varied symptomatology and exam findings. The diagnosis of asthma is made through a combination of clinical assessment and diagnostic testing.

METHODS

A literature review was conducted through PubMed, focusing on systematic reviews and practice parameters. The highest-quality studies and those including the highest number of patients were included. References were reviewed for additional relevant articles.

RESULTS

Patients with asthma present with the symptoms of cough, dyspnea, and wheezing. The physical exam can demonstrate hyperinflation, wheezing, and increased work of breathing, but most patients will present with a normal pulmonary exam because they are between episodes. The symptoms and examination of patients with asthma varies greatly from patient to patient and within the same patient over time. The diagnosis of asthma in the pediatric population may be more difficult because the classic symptoms may not be present in many of those patients.

CONCLUSION

The diagnosis of asthma is made in the setting of clinical history, physical exam, and diagnostic testing. The astute physician will rely on all 3 of these factors when making the diagnosis.

Improving Patient Satisfaction in the Outpatient Otolaryngology Clinic

Objectives:

(1) Determine patient and provider factors associated with patient dissatisfaction in an otolaryngology clinic. (2) Identify strategies to improve the patient experience.

Methods:

Patient satisfaction surveys were prospectively collected in an academic otolaryngology clinic from January 2011 through March 2013. Patient variables (age, insurance type, established vs new patient, diagnosis, and treatability of condition) and provider variables (years in practice, subspecialty, and clinic wait time) were retrospectively analyzed to determine factors associated with patient dissatisfaction. “Treatability” was graded on a scale of 1 to 5, with diagnoses having a clear treatment option (ie, tonsillectomy for chronic tonsillitis) = 1, and diagnoses with no therapeutic options available (ie, tinnitus) = 5.

Results:

The cohort included 820 patient satisfaction surveys and charts. Stepwise linear regression analysis identified no single patient or provider variable associated with poor satisfaction scores. Cluster analysis evaluating the interplay between variables identified 5 unique clusters of patients. Satisfaction scores in 4 of the clusters were in the 99th percentile, while the remaining cluster ranked in the 10th percentile. This cluster consisted of a higher proportion of new patients with difficult-to-treat otologic conditions who described their wait time as excessive and were more likely to be self-pay.

Conclusions:

Several factors influence patient satisfaction in an otolaryngology clinic. In this study, variables associated with lower patient satisfaction scores included patients with longer clinic wait times, “difficult to treat” otologic diagnoses, and new patients. Addressing the issues common in this population to better meet their needs and expectations may improve overall patient satisfaction.

Salivary gland disorders

Salivary gland disorders include inflammatory, bacterial, viral, and neoplastic etiologies. The presentation can be acute, recurrent, or chronic. Acute suppurative sialadenitis presents as rapid-onset pain and swelling and is treated with antibiotics, salivary massage, hydration, and sialagogues such as lemon drops or vitamin C lozenges. Viral etiologies include mumps and human immunodeficiency virus, and treatment is directed at the underlying disease. Recurrent or chronic sialadenitis is more likely to be inflammatory than infectious; examples include recurrent parotitis of childhood and sialolithiasis. Inflammation is commonly caused by an obstruction such as a stone or duct stricture. Management is directed at relieving the obstruction. Benign and malignant tumors can occur in the salivary glands and usually present as a painless solitary neck mass. Diagnosis is made by imaging (e.g., ultrasonography, computed tomography, magnetic resonance imaging) and biopsy (initially with fine-needle aspiration). Overall, most salivary gland tumors are benign and can be treated with surgical excision.

Conditioning the cochlea to facilitate survival and integration of exogenous cells into the auditory epithelium

The mammalian auditory epithelium (AE) cannot replace supporting cells and hair cells once they are lost. Therefore, sensorineural hearing loss associated with missing cells is permanent. This inability to regenerate critical cell types makes the AE a potential target for cell replacement therapies such as stem cell transplantation. Inserting stem cells into the AE of deaf ears is a complicated task due to the hostile, high potassium environment of the scala media in the cochlea, and the robust junctional complexes between cells in the AE that resist stem cell integration. Here, we evaluate whether temporarily reducing potassium levels in the scala media and disrupting the junctions in the AE make the cochlear environment more receptive and facilitate survival and integration of transplanted cells. We used sodium caprate to transiently disrupt the AE junctions, replaced endolymph with perilymph, and blocked stria vascularis pumps with furosemide. We determined that these three steps facilitated survival of HeLa cells in the scala media for at least 7 days and that some of the implanted cells formed a junctional contact with native AE cells. The data suggest that manipulation of the cochlear environment facilitates survival and integration of exogenously transplanted HeLa cells in the scala media.

Treatment of Oral Cavity Venous Malformations with the Nd:YAG Laser Using the Underwater Technique

Mucosal involvement of venous malformations can cause bleeding, pain, and functional impairment. Treatment options include surgery, sclerotherapy, or laser therapy. Neodymium:yttrium aluminum garnet (Nd:Yag) laser therapy has been used to treat mucosal disease, but few studies have focused purely on the oral cavity. We present a retrospective review of 4 patients (5 subsites) with oral cavity venous malformations treated with the Nd:YAG laser using an underwater technique. Photographs of the venous malformations before and after treatment were evaluated by 2 blinded physicians. A visual analog scale was used to rate the treatment. The medical record was reviewed to assess change in symptoms and to note complications. Four sites were rated as having “significant improvement” and 1 site as “some improvement.” Our study demonstrates that the Nd:YAG laser can be a feasible option in the treatment of venous malformations of the oral cavity.

Tympanoplasty with intact canal wall mastoidectomy for cholesteatoma: long-term hearing outcomes

OBJECTIVES/HYPOTHESIS

To review long-term hearing results after intact canal wall mastoidectomy with tympanoplasty for treatment of cholesteatoma and to identify factors associated with improved hearing outcomes.

STUDY DESIGN

A retrospective analysis of all cases of cholesteatoma treated with intact canal wall mastoidectomy at a single institution by the senior author over a period of 9 years, for which at least 2 years of follow-up data exist.

METHODS

Patient and disease information was collected retrospectively and analyzed.

RESULTS

There were 148 patients with 156 affected ears treated and followed for a median of 5.3 years (interquartile range, 3.6-7.4 years). The majority of the operations (144/156, 92%) were staged. Hearing data were available for 150 ears. The overall postoperative mean air-bone gap was ≤ 20 dB in 64% of patients. This was maintained long term in most patients, with 59% of patients still with an air-bone gap ≤ 20 dB at a median follow-up of 5.3 years. The presence of an intact stapes did not affect initial hearing outcomes, but the group with an intact stapes had improved long-term hearing results compared to those without an intact stapes (71% vs. 42% air-bone gap ≤ 20 dB, P < .001). The presence of a malleus handle also led to superior long-term hearing outcomes (72% vs. 48% air-bone gap ≤ 20 dB, P = .005).

CONCLUSIONS

Long-term hearing results from intact canal wall mastoidectomy with tympanoplasty are excellent, with the majority of patients maintaining a small air-bone gap long term. The presence of a stapes and/or malleus handle confers improved long-term hearing outcomes.

Perioperative strategies to improve sinus surgery outcomes in patients with cystic fibrosis: a systematic review

OBJECTIVES

Review the literature for intraoperative techniques and postoperative practices after functional endoscopy sinus surgery (FESS) that may improve outcomes in patients with cystic fibrosis (CF).

DATA SOURCES

PubMed and the Cochrane Library.

REVIEW METHODS

A systematic review of the literature was performed. Articles from 1990 to 2012 were searched using the terms sinus surgery and cystic fibrosis with studies limited to the English language and human subjects. Abstracts were reviewed to identify relevant original manuscripts. Bibliographies of relevant articles were examined to identify additional manuscripts.

RESULTS

The initial PubMed search identified 169 articles. One additional article was identified through the Cochrane Library. After reviewing the abstracts, 41 selected studies were examined in further detail, and 22 articles were ultimately selected for suitability for this review. The bibliographies of these articles were reviewed and no additional articles were identified. Perioperative strategies included postoperative medical therapies, intraoperative techniques and image guidance, intranasal corticosteroid injection, dornase alfa, gene therapy, and second-look procedures. Most studies were limited to case series with relatively small numbers of patients. Very few randomized controlled studies were identified.

CONCLUSION

Despite the prevalence of recurrent sinonasal disease after FESS in patients with CF, evidence for definitive perioperative management in this population is lacking. Most recommendations are based on small case series. Multicenter studies to evaluate perioperative strategies that improve FESS outcomes in patients with CF are warranted.

Tympanoplasty with Intact Canal Wall Mastoidectomy for Cholesteatoma

Objective

With different mastoidectomy approaches available to the surgeon for treatment of cholesteatoma, we review long-term outcomes of intact canal wall (ICW) mastoidectomy with tympanoplasty.

Study Design

Case series with chart review.

Setting

Academic medical center.

Subjects and Methods

All cases of cholesteatoma treated with ICW mastoidectomy by the senior author over a period of 9 years for which at least 2 years of follow-up data exist. Patient and disease information was collected retrospectively and analyzed.

Results

One hundred forty-eight patients with 156 affected ears were treated and followed for a median of 5.3 years (range, 2.1-14.8). The majority of the operations (144/156, 92%) were staged. Of those that were staged, 51/144 (35%) had residual cholesteatoma at the second stage. Thirteen patients (8%) had recurrence of their cholesteatoma, of which 6 required a subsequent canal wall down (CWD) mastoidectomy.

Conclusions

ICW mastoidectomy with tympanoplasty continues to be a successful treatment for cholesteatoma. We found a substantial residual rate at the second stage, justifying the necessity of staging in most cases. Recurrence rate of cholesteatoma using this technique is low, as is the progression to CWD mastoidectomy.

Assessment of Otolaryngic Knowledge in Primary Care Residents

Objectives

(1) Determine the amount of exposure to otolaryngology in medical training of non-otolaryngology residents. (2) Evaluate the general otolaryngic knowledge in these residents.

Study Design

Cross-sectional survey.

Setting

Academic medical center.

Subjects and Methods

A 10-question multiple-choice quiz was given to residents in family practice, pediatrics, emergency medicine, and internal medicine during scheduled educational conferences. Residents were also asked if they ever participated in an otolaryngology rotation during medical school or residency. Medical students and otolaryngology residents completed the quiz to act as controls.

Results

A total of 98 examinations were analyzed (49 non-otolaryngology residents, 10 otolaryngology residents, and 39 second-year medical students). Only 24% of the non- otolaryngology residents had an otolaryngology rotation during medical school. The same amount (24%) had a rotation during residency. The average percentage correct on the quiz was 48%, 56%, and 92% for medical students, non-otolaryngology, and otolaryngology residents, respectively ( P < 0.05). Questions with surprising results included one with an endoscopic image of the middle turbinate and examinees asked to identify the structure (non-otolaryngology residents = 18% correct). A laryngectomy stoma was shown and participants asked what would happen if the stoma was occluded for 10 minutes (non-otolaryngology residents = 20% correct).

Conclusion

In this sample of non-otolaryngology residents, a minority experienced a clinical rotation in otolaryngology during medical school or residency. This nonvalidated questionnaire also suggested significant deficiencies in basic otolaryngic knowledge in these residents. Identifying mechanisms to improve exposure to otolaryngology in the medical training curriculum is needed.

General Otolaryngology Knowledge in Primary Care Residents

Objective: 1) Determine the amount of exposure to otolaryngology in medical training of nonotolaryngology residents (NOR). 2) Evaluate the general otolaryngology-related knowledge in these residents.

Method: A 10-question multiple-choice quiz was given to residents in family practice, pediatrics, emergency medicine, and internal medicine during scheduled educational conferences. Residents were also asked if they ever participated in an otolaryngology rotation during medical school or residency. Medical students and otolaryngology residents completed the quiz to act as controls.

Results: A total of 49 NOR and 44 medical students answered the questionnaire. Only 24% of the NOR had an otolaryngology rotation during medical school. The same amount (24%) had a rotation during residency. The average percentage correct on the quiz was 49%, 57%, and 91% for medical students, NOR, and otolaryngology residents respectively ( P < .05). Questions with surprising results included one with an endoscopic image of the middle turbinate, and examinees were asked to identify the structure (NOR = 18% correct). A laryngectomy stoma was also shown, and participants were asked what would happen if the stoma was occluded for 10 minutes (NOR = 20% correct).

Conclusion: In this sample of nonotolaryngology residents, a minority experienced a clinical rotation in otolaryngology during medical school or residency. This nonvalidated questionnaire also suggested significant deficiencies in basic otolaryngology knowledge in these residents. Identifying mechanisms to improve exposure to otolaryngology in the medical training curriculum is needed.

Clinical and pathologic predictors of recurrence and survival in spindle cell squamous cell carcinoma

OBJECTIVE

To determine clinicopathologic predictors of recurrence and survival in patients with spindle cell squamous cell carcinoma (SpSCC).

STUDY DESIGN

Historical cohort study.

SETTING

Tertiary care hospital.

SUBJECTS AND METHODS

Forty-eight patients (mean age, 65.2 years; 35 men, 13 women) who underwent definitive treatment for pathologically confirmed SpSCC between 1987 and 2009 were identified and reviewed. The main outcome measures were time to recurrence and overall survival, while controlling for clinical and pathologic parameters (age, sex, TNM classification, stage, tumor subsite, smoking status, treatment modality, margin status).

RESULTS

Of 48 patients, there were 25 oral cavity, 15 laryngeal, 7 oropharyngeal, and 1 maxillary sinus tumors. Treatment included surgery in 32, radiation in 9, and concurrent chemoradiation in 7 patients. The 3-year overall survival for the cohort was 62% with a median follow-up of 59 months; 52.1% (25/48) of patients developed a recurrence, and 88% (22/25) recurred locally or locoregionally. Recurrence occurred within 2 years in 72% (18/25) of patients. Age, sex, initial T and N classification, overall stage, tumor subsite, smoking status, treatment modality, and margin status were not predictive of recurrence or overall survival.

CONCLUSION

Patients with SpSCC are at high risk of developing locoregional recurrence, but no measured clinical or pathologic parameter was predictive of survival. Although overall survival is similar to that of patients with conventional SCC, closer follow-up should be considered in these patients to allow earlier detection and treatment of these locally aggressive tumors.

Orbitocranial approach for treatment of adenoid cystic carcinoma of the lacrimal gland

OBJECTIVES

Multiple treatment options exist for management of adenoid cystic carcinoma of the lacrimal gland. Our objective was to perform an analysis of outcomes in a cohort of patients with adenoid cystic carcinoma of the lacrimal gland treated identically with an orbitocranial approach.

METHODS

We performed a retrospective review of 7 consecutive patients who presented to a tertiary care academic medical center between 1995 and 2009 with adenoid cystic carcinoma of the lacrimal gland.

RESULTS

All patients were treated with an orbitocranial approach to tumor resection followed by postoperative radiotherapy. The mean and median follow-up times were 39 and 19 months, respectively (range, 7 to 138 months). Six patients had orbital reconstruction using free tissue transfer, and 1 patient had a split-thickness skin graft to line the orbital cavity. Two patients developed distant metastases 18 months and 29 months after surgery and ultimately died with disease. Five patients are alive without disease.

CONCLUSIONS

The orbitocranial approach followed by postoperative irradiation achieves excellent local and regional control rates for adenoid cystic carcinoma of the lacrimal gland, although patients remain at risk long-term for distant metastases. Orbital bone removal to obtain adequate margins should be a routine part of tumor resection for these malignancies.

Manure Nutrient Excretion by Lactating Cows Fed Exogenous Phytase and Cellulase

The effect of an exogenous phytase and cellulase-containing enzyme formulation on nutrient digestibility and excretion was evaluated in 24 Holstein cows. Cows were fed corn silage- and alfalfa silage-based diets with or without a cellulase-phytase blend for 31 d in a continuous random design. Treatment groups were balanced for parity, days in milk, and mature-equivalent projected milk yield. Diets contained 37% forage, 18.3% crude protein, 35.4% neutral detergent fiber, 18% acid detergent fiber, and 0.42% P (no supplemental P). Cows were fed once daily in Calan doors and milked 2 times daily. Body weight and milk yield were recorded at each milking. Milk samples were collected on d 28 to 31 at 8 consecutive milkings. On d 28 to 31, fecal grab samples were collected every 8 h, with sampling times advanced by 2 h each day. Feces samples were pooled by cow. Feed and feces samples were analyzed for acid detergent lignin (used as an internal marker) and for N, P, neutral detergent fiber, and acid detergent fiber. Days in milk were similar between treatments, and body weight and milk yield were unaffected by treatment. Cows fed the enzyme formulation had reduced fecal dry matter, neutral detergent fiber, and acid detergent fiber excretion and reduced fecal excretion of N and P. Apparent digestibility of dry matter, acid detergent fiber, neutral detergent fiber, and N tended to increase with the enzyme formulation. Addition of an exogenous phytase and cellulase enzyme formulation to diets for lactating cows reduced fecal nutrient excretion.

Cdc42 stimulates RNA splicing via the S6 kinase and a novel S6 kinase target, the nuclear cap-binding complex

Cdc42 is a low molecular weight GTP-binding protein that plays a key regulatory role in a variety of cellular activities. The importance of the coordination of different cell functions by Cdc42 is underscored by the fact that a constitutively active Cdc42 mutant induces cellular transformation. In this study, we describe a novel function for Cdc42: its ability to stimulate pre-messenger RNA splicing. This activity is dependent on cysteine 37 in the effector loop of Cdc42 but is not dependent on cell growth. A likely candidate protein for mediating the Cdc42 effects on pre-mRNA splicing is the nuclear RNA cap-binding complex (CBC), which plays a key role in an early step of cap-dependent RNA splicing. Activation of the CBC by Cdc42 can be inhibited by rapamycin. Additionally, phosphatidylinositol 3-kinase and the Cdc42 effector, pp70 S6 kinase, stimulate the RNA cap-binding activity of the CBC. S6 kinase may directly target the CBC in vivo as it can phosphorylate the 80-kDa subunit of the CBC, CBP80, at residues that are subject to a growth factor-dependent and rapamycin-sensitive phosphorylation in vivo. Together these data suggest the involvement of a Cdc42-S6 kinase pathway in the regulation of RNA splicing, mediated by an increase in capped RNA binding by the CBC, as well as raise the possibility that the effects of Cdc42 on cell growth may be due in part to its regulation of RNA processing.

Signal transduction and post-transcriptional gene expression

Traditionally, growth factor-coupled signaling to the nucleus has been thought to be primarily directed toward transcriptional regulation. However, there are now increasing indications from a diversity of experimental systems that other aspects of RNA processing, including translation, lifetime and stability, and splicing are under strict growth factor control. In this review, we present the emerging evidence for growth factor signaling pathways that impact on these different RNA processing events. Particularly noteworthy is the realization that growth factor signaling through Ras can effect the regulation of two RNA cap-binding proteins, the cytosolic eIF-4E complex, which is necessary for initiating translation, and the nuclear cap-binding complex, the CBC, which plays a role in cap-dependent pre-mRNA splicing, U snRNA export and 3'-end processing. This, taken together with other findings that demonstrate the ability of stress response pathways and the small G protein, Cdc42, to activate the CBC, raises some interesting possibilities regarding how signaling to the two cellular RNA cap-binding protein complexes may coordinate the growth-coupled regulation of gene expression at the level of RNA processing.

The nuclear cap-binding complex is a novel target of growth factor receptor-coupled signal transduction

In an attempt to further understand how nuclear events (such as gene expression, nuclear import/export, and cell cycle checkpoint control) might be subject to regulation by extracellular stimuli, we sought to identify nuclear activities under growth factor control. Using a sensitive photoaffinity labeling assay that measured [alpha-32P]GTP incorporation into nuclear proteins, we identified the 20-kDa subunit of the nuclear cap-binding complex (CBC) as a protein whose binding activity is greatly enhanced by the extracellular stimulation of serum-arrested cells. The CBC represents a 20- and 80-kDa heterodimer (the subunits independently referred to as CBP20 and CBP80, respectively) that binds the 7-methylguanosine cap on RNAs transcribed by RNA polymerase II. This binding facilitates precursor messenger RNA splicing and export. We have demonstrated that the [alpha-32P]GTP incorporation into CBP20 was correlated with an increased ability of the CBC to bind capped RNA and have used the [alpha-32P]GTP photoaffinity assay to characterize the activation of the CBC in response to growth factors. We show that the CBC is activated by heregulin in HeLa cells and by nerve growth factor in PC12 cells as well as during the G1/S phase of the cell cycle and when cells are stressed with UV irradiation. Additionally, we show that cap-dependent splicing of precursor mRNA, a functional outcome of CBC activation, can be catalyzed by growth factor addition to serum-arrested cells. Taken together, these data identify the CBC as a nuclear target for growth factor-coupled signal transduction and suggest novel mechanisms by which growth factors can influence gene expression and cell growth.

Long-term effects of insulin-like growth factor (IGF)-I treatment on serum IGFs and IGF binding proteins in adolescent patients with growth hormone receptor deficiency

OBJECTIVE

The aim of this investigation was to study the effect of relatively high dose IGF-I therapy given for several months, on serum levels of IGF-I, IGF-II and IGFBP-3, and on IGF-I pharmacokinetics in patients with growth hormone insensitivity due to GH receptor dysfunction.

DESIGN AND PATIENTS

Two adolescent subjects from Ecuador were treated with recombinant IGF-I at a dosage of 120 micrograms/kg s.c. twice daily, in combination with a GnRH analogue for 8 months.

MEASUREMENTS

Serum was sampled at baseline and at 3-8 months, for determination of IGF-I, IGF-II and IGFBP-3 by radioimmunoassay, and for evaluation of IGFBPs and IGFBP-3 protease activity by Western ligand blot and protease assay, respectively.

RESULTS

Peak serum IGF-I levels ranged from 272 to 492 micrograms/l. Mean serum IGF-II levels were decreased concurrently with the increase in IGF-I. Serum IGFBP-3 levels failed to rise with prolonged IGF-I treatment. There was no apparent change in the half-life of IGF-I during the treatment period.

CONCLUSIONS

IGF-I administration does not increase serum levels of IGFBP-3 or significantly alter IGF-I pharmacokinetics.

Insulin-like growth factor binding protein-3 concentrations and insulin-like growth factor binding protein-3 protease activity in sera of patients with malignant solid tumors or leukemia

IGF binding proteins (IGFBP) regulate the bioavailability and bioactivity of IGF. The major IGFBP in serum is IGFBP-3. We investigated whether sera from children with malignancies show alterations in levels of IGFBP-3 as measured by Western ligand blot analysis (WLB) and RIA with alpha IGFBP-3gl, a specific rabbit polyclonal antibody. Furthermore, IGFBP-3 proteolysis was quantified by densitometric analysis of [125I]IGFBP-3 protease assays, and IGFBP-3 fragments were visualized by Western immunoblot with alpha IGFBP-3gl. We examined sera from 21 children with solid tumors, five patients with sarcoma who had reached complete remission, and 13 children with acute leukemia. Serum samples were collected at diagnosis, before initiation of therapy. Sera of 10 healthy children served as normal controls. Children with solid tumor or leukemia had significantly higher (p < 0.001) IGFBP-3 protease activity in serum than did normal controls or patients with sarcoma in complete remission. Corresponding to this finding, densitometry of WLB showed lower IGFBP-3 levels in sera of children with malignancies in comparison with normal controls. The negative correlation (p < 0.001, r = -0.80) between IGFBP-3 proteolysis, as measured by [125I]IGFBP-3 protease assay, and IGFBP-3 band density on WLB indicates that proteolysis is the probable reason for reduction of IGFBP-3 on WLB. IGFBP-3 concentrations measured by RIA were in the normal range for most patients, further indicating that differences in serum IGFBP-3 levels measured by WLB reflect protease activity.(ABSTRACT TRUNCATED AT 250 WORDS)

Effects of insulin-like growth factor I treatment on the molecular distribution of insulin-like growth factors among different binding proteins

The molecular distribution of insulin-like growth factor I (IGF-I) and IGF-II among the IGF binding proteins (IGFBPs) was studied before and during IGF-I therapy in Ecuadorean adults with growth hormone receptor deficiency (GHRD). Of the total circulating IGF-I and IGF-II, 70% was carried by the 150 kDa complex in normal subjects, while in patients with GHRD, 50% of serum IGF-I, but only 30-35% of serum IGF-II, was measured within the 150 kDa IGFBP-3 region. Administration of IGF-I altered the concentration of IGF-I and IGF-II, although the percentage of total IGF measured within each IGFBP region was not affected, as the increase in IGF-I and the decrease in IGF-II were proportional. Similarly, serum concentrations of IGFBP-3 and the acid-labile subunit, measured by radioimmunoassay, were unaltered. Thus, administration of IGF-I to patients with GHRD was unable to correct the aberrant distribution of IGFs among the IGFBPs.

The composition and distribution of insulin-like growth factors (IGFs) and IGF-binding proteins (IGFBPs) in the serum of growth hormone receptor-deficient patients: effects of IGF-I therapy on IGFBP-3

We have previously reported that adult GH receptor-deficient (GHRD) patients treated subcutaneously with recombinant human insulin-like growth factor (IGF)-I have increased serum IGF-I levels and decreased IGF-II levels, whereas IGF-binding protein-3 (IGFBP-3) levels were unchanged. To further investigate the effects of IGF-I administration upon the IGF-IGFBP axis in GHRD, we have examined: 1) the molecular distribution of IGF-I and IGF-II among the IGFBPs; 2) the composition and distribution of the IGFBPs, in particular IGFBP-3; and 3) the acid labile subunit (ALS). Serum samples from adult GHRD patients who were treated sc with recombinant human IGF-I (40 micrograms/kg, sc, twice a day) or from normal Ecuadorian adults were incubated with [125I]IGF-II and subjected to neutral size-exclusion chromatography. The fractions were then subjected to Western ligand blot, Western immunoblot, IGFBP-3 RIA, and IGF RIAs. Serum of healthy adults incorporated [125I]IGF-II into the 150- and 44-kilodalton (kDa) IGFBP region. The 150-kDa IGFBP region contained most of the circulating IGFBP-3, whereas the 44-kDa IGFBP region contained mainly IGFBP-1, 2, and 4. The 150-kDa region also contained a unique 28-kDa immunoreactive form of IGFBP-3, which was not detectable by Western ligand blot. Endogenous IGF-I and IGF-II were distributed equally in the 150- and 44-kDa IGFBP regions. Sera from GHRD patients mainly incorporated [125I]IGF-II into the 44-kDa IGFBP region. Similar to control sera, the 150-kDa IGFBP region contained IGFBP-3, albeit at lower concentrations. The 44-kDa IGFBP region contained all IGFBPs including 50% of the total immunoreactive IGFBP-3. The two immunoreactive forms of IGFBP 3 (40- to 45-kDa doublet and 28-kDa band) were present in both IGFBP regions. The IGF size-distribution study revealed that the 150-kDa IGFBP region carried half of the circulating endogenous IGF-I, but only 30% of the IGF-II. Concentrations of the ALS were consistently low. Administration of IGF-I to GHRD patients was unable to increase concentrations of the molecular forms of IGFBP-3, correct the aberrant distribution of IGFs among the IGFBPs, or increase serum concentrations of ALS. In conclusion, we have found two forms of IGFBP-3 associated with IGF and ALS, which are capable of forming the ternary 150-kDa complex in healthy adult serum. The ratio of these two forms of IGFBP-3 and their distribution in serum was different between GHRD and control patients.(ABSTRACT TRUNCATED AT 400 WORDS)

Insulin-like growth factors (IGFs) stimulate and dexamethasone inhibits IGF binding protein (BP)-5 expression in a mouse pituitary cell line

The mouse pituitary cell line AtT-20 was found to secrete two low MW IGFBPs into conditioned medium (CM). The major IGFBP migrated at approximately 29 kDa and a minor IGFBP of 24 kDa was also present on western ligand blots (WLB). Both IGFBPs were purified from CM by IGF-affinity chromatography followed by reverse phase-FPLC. N-terminal analysis revealed that the first 10 amino acids of the 29 kDa and the 24 kDa IGFBPs were homologous to corresponding sequences of both human and rat IGFBP-5 and IGFBP-4, respectively. The 24 kDa IGFBP also crossreacted with a new antiserum specific for rodent IGFBP-4. The concentrations of both IGFBPs were increased by the addition of IGF-I, IGF-II, or insulin to the cell cultures, with IGFBP-5 demonstrating the greatest hormonal stimulation. The effects of IGF-I on IGFBP-5 expression were both time and dose dependent, with IGF-I being more potent than IGF-II, and IGF-II more potent than insulin. The relative potencies of these hormones in stimulating IGFBP-5 production were consistent with the peptides acting through the type-I IGF receptor. Similarly, the IGF-II analog [Leu 27]-IGF-II, which has very low affinity for the type-I receptor, only slightly stimulated an increase in IGFBP-5. Addition of dexamethasone to the cultures decreased both basal and IGF-stimulated IGFBP-5 production. Northern blotting demonstrated that IGF-I increased the expression of the mRNA for IGFBP-5, whereas dexamethasone decreased it. Together, these data suggest that the IGFs can increase IGFBP-5 production at both the protein and mRNA level.

Elevated levels of insulin-like growth factor-binding protein-2 in the serum of prostate cancer patients

We have previously documented the presence of specific insulin-like growth factor (IGF)-binding protein (IGFBPs) in seminal plasma and prostate epithelial cell-conditioned medium IGFBP-2 is the prevalent IGFBP in both fluids. To assess whether patients with prostate carcinoma have alterations in serum IGFP levels related to the production of IGFBPs by their tumors, we performed Western ligand blots (WLB) and IGFBP-2 RIA on serum samples from 32 patients with prostate carcinoma of various degrees of clinical severity and compared them to results in 16 healthy age-matched controls. We have also measured serum IGF-I and -II by RIA. The mean level of IGFBP-2 in the prostate cancer patients was 170% of control levels by WLB analysis and 195% of control levels by RIA (P < 0.01). The degree of elevation of IGFBP-2 was related to the stage of the tumor and the levels of the serum tumor marker, prostate-specific antigen. Serum IGFBP-3 levels determined by WLB and serum IGF-I and IGF-II levels measured by RIA after acid chromatography were not different among the subjects with cancer and the normal controls. We conclude that IGFBP-2, which is the main IGFBP produced by prostate epithelial cells, is elevated in the serum of patients with prostate carcinoma, and that the degree of this elevation is related to serum prostate-specific antigen levels and the stage of the tumor. We speculate that prostate-derived IGFBPs may be secreted by prostate tumors and could e of value in understanding the pathophysiology of prostatic tumor growth as well as provide potential diagnostic markers.

Measurement and characterization of insulin-like growth factor binding protein-3 in human biological fluids: discrepancies between radioimmunoassay and ligand blotting

The inability to detect insulin-like growth factor binding protein-3 (IGFBP-3) in some circumstances by Western ligand blot analysis has emphasized the need to characterize IGFBPs by both ligand binding and immunological techniques. In this study, we have: 1) characterized and quantified IGFBP-3 in nonpregnancy, pregnancy, and fetal cord serum, follicular, peritoneal, and amniotic fluid, seminal plasma, cerebrospinal fluid (CSF), and urine; 2) established a new IGFBP-3 RIA that detects both intact and fragments of IGFBP-3; 3) identified both intact and fragments of IGFBP-3 by Western immunoblot techniques; and 4) addressed the discordance between Western ligand blot analysis and RIA by assessing fluids for IGFBP proteolytic activity. All fluids examined, except pregnancy serum, CSF, and amniotic fluid, displayed a 44-34-kilodalton (kDa) IGFBP-3 doublet by Western ligand blot analysis. Western immunoblot analysis using specific IGFBP-3 antiserum showed a 44-34-kDa IGFBP-3 doublet and a 28-kDa fragment in nonpregnancy serum, fetal cord serum, follicular fluid, and peritoneal fluid. The immunoreactive 42-38-kDa doublet was faint in urine and seminal plasma. IGFBPs in CSF did not cross-react with IGFBP-3 antiserum. Pregnancy serum and amniotic fluid contained only the 28-kDa fragment when compared against equal volumes of nonpregnancy serum. With the development of an IGFBP-3 RIA, IGFBP-3 could be accurately measured; urine, CSF, and seminal plasma contained the lowest levels of IGFBP-3 at 27 +/- 3 ng/ml (mean +/- SEM), 110 +/- 26 ng/ml, and 209 +/- 56 ng/ml, respectively. In increasing concentration: fetal cord serum contained 753 +/- 101 ng/ml; peritoneal fluid, 1124 +/- 130 ng/ml; follicular fluid, 2356 +/- 211 ng/ml; nonpregnancy serum, 3556 +/- 508 ng/ml; pregnancy serum, 3718 +/- 842 ng/ml; and amniotic fluid, 5150 +/- 688 ng/ml. The measurable concentrations of IGFBP-3 in CSF and the high concentrations measured in pregnancy serum and amniotic fluid conflicted with Western blot analysis. Thus, fluids were assessed for IGFBP proteolytic activity by incubation with a source of IGFBP-3, either nonpregnancy serum or purified IGFBP-3. All fluids displayed some proteolytic activity with either assay. Fluids with little protease activity (nonpregnancy serum, follicular fluid, and urine) showed a close relationship between immunoassayable IGFBP-3 by RIA and IGFBP-3 band intensity by Western ligand blot. Fluids with high proteolytic activity (pregnancy serum, CSF, seminal plasma, peritoneal fluid, and amniotic fluid) gave discrepant IGFBP-3 values between RIA and Western ligand blot.(ABSTRACT TRUNCATED AT 400 WORDS)

Dendritic organization of class II (inter)neurons in the dorsal lateral geniculate nucleus of the tree shrew: observations based on Golgi, immunocytochemical, and biocytin methods

In this report we examine the dendritic organization of putative interneurons (class II cells) in different layers of the dorsal lateral geniculate nucleus of the tree shrew. The results show that there is considerable morphological diversity within this class, but that two broad groups can be identified: neurons whose dendrites remain within a layer or its adjacent interlaminar zones (intralaminar class II cells); and neurons whose dendrites cross into an adjacent layer(s) (interlaminar class II cells). The majority of class II cells in every layer have intralaminar dendrites, some of which are oriented along a particular axis, and others that are organized radially. The paired layers (1 and 2, 4 and 5) contain a particular group of intralaminar class II cells that have radially organized dendrites and elaborate claw-like appendages. The dendrites of interlaminar class II cells are organized along lines of projection and extend across as many as four layers. These cells often reside close to or within the interlaminar zones. Overall, the organization of class II cells seems to follow a pattern similar to the class I (relay) cells identified previously. Most have intralaminar dendrites, which presumably underlie the fidelity of signals transmitted from the retina to a particular layer. However, there are also a number of other cells whose processes cross laminar borders, presumably to affect integrative functions within the nucleus.