Effortful swallow and the Mendelsohn maneuver are two common strategies to improve disordered swallowing. We used high-resolution manometry (HRM) to quantify the effects of these maneuvers on pressure and timing characteristics. Fourteen normal subjects swallowed multiple, five ml water boluses using three techniques: normal swallow; effortful swallow; and Mendelsohn maneuver. Maximum pressure, rate, duration, area integral, and line integral were determined for the velopharynx and tongue base. Minimum pressure, duration of pressure-related change, duration of nadir pressure, maximum pre-opening and post-closure pressure, area integral, and line integral were recorded for the upper esophageal sphincter (UES). Area and line integrals of the velopharyngeal pressure curve significantly increased with the Mendelsohn maneuver; the line integral increased with the effortful swallow. Pre-opening UES pressure decreased significantly for the Mendelsohn, while post-closure pressure tended to increase insignificantly for both maneuvers. UES area and line integrals as well as nadir UES pressure duration increased with both maneuvers. Maneuver-dependent changes were observed primarily at the velopharynx and UES. These regions are critical to safe swallowing, as the velopharynx provides positive pressure at the bolus tail while the UES allows a bolus to enter the esophagus without risk of regurgitation. Integrals were more responsive than maximum pressure or duration and should be investigated further.
pharyngeal pressure; swallowing maneuver; high-resolution manometry; deglutition; deglutition disorder
Parasympathetic nerves are a vital component of the progenitor cell niche during development, maintaining a pool of progenitors for organogenesis. Injured adult organs do not regenerate after parasympathectomy, and there are few treatments to improve organ regeneration, particularly after damage by therapeutic irradiation. Here we show that restoring parasympathetic function with the neurotrophic factor neurturin increases epithelial organ regeneration after damage. We use mouse salivary gland explant culture containing fluorescently-labeled progenitors, and injure the tissue with irradiation. The progenitors survive, parasympathetic function is diminished, and epithelial apoptosis reduces expression of neurturin, which increases neuronal apoptosis. Treatment with neurturin reduces neuronal apoptosis, restores parasympathetic function, and increases epithelial regeneration. Furthermore adult human salivary glands damaged by irradiation also have reduced parasympathetic innervation. We propose that neurturin will protect the parasympathetic nerves from damage and improve organ regeneration. This concept may be applicable for other organs where parasympathetic innervation influences their function.
There is debate concerning the mechanism of Eustachian tube (ET) ventilation. While a mechanism of complete opening has been advocated previously, sequential contraction of the levator veli palatini and medial pterygoid muscles followed by the tensor veli palatini and lateral pterygoid muscles may produce a transient sequential opening mechanism, allowing an air bolus to traverse the ET. This may explain confusion surrounding sonotubometry reports that not every swallow leads to sound passage in normal subjects. We hypothesize that the ET may not need to open completely when ventilating the middle ear; rather, a discrete air bolus can pass through it.
Subjects and Methods
Five normal and five disordered subjects underwent low-radiation dose cine computed tomography (CT) scans of the ET. Sixteen contiguous 2.5 mm slice locations were chosen through a 4 cm area in the nasopharynx that were parallel to and encompassed the entire ET. Twelve images were acquired at each slice over 4.8 seconds during swallowing and other tasks. Serial images were analyzed.
An air bolus was observed passing through the ET in the normal subjects, but not the subject with ET dysfunction. Medial and lateral pterygoid contractions were also observed.
A new hypothetical mechanism of transient sequential ET ventilation is presented. This is not a definitive conclusion, as the number of scans taken and maneuvers used was limited. Improved understanding of ET ventilation may facilitate management of middle ear disease as treatment evolves from ventilatory tube placement to ET manipulation.
Eustachian tube ventilation; Eustachian tube dysfunction; patulous Eustachian tube
To use contemporary labor data to examine the labor patterns in a large, modern obstetric population in the United States.
Data were from the Consortium on Safe Labor, a multicenter retrospective study that abstracted detailed labor and delivery information from electronic medical records in 19 hospitals across the United States. A total of 62,415 parturients were selected who had a singleton term gestation, spontaneous onset of labor, vertex presentation, vaginal delivery, and a normal perinatal outcome. A repeated-measures analysis was used to construct average labor curves by parity. An interval-censored regression was used to estimate duration of labor stratified by cervical dilation at admission and centimeter by centimeter.
Labor may take over 6 hours to progress from 4 to 5 cm and over 3 hours to progress from 5 to 6 cm of dilation. Nulliparas and multiparas appeared to progress at a similar pace before 6 cm. However, after 6 cm labor accelerated much faster in multiparas than in nulliparas. The 95th percentile of the 2nd stage of labor in nulliparas with and without epidural analgesia was 3.6 and 2.8 hours, respectively. A partogram for nulliparas is proposed.
In a large, contemporary population, the rate of cervical dilation accelerated after 6 cm and progress from 4 to 6 cm was far slower than previously described. Allowing labor to continue for a longer period before 6 cm of cervical dilation may reduce the rate of intrapartum and subsequent repeat cesarean deliveries in the United States.
Disordered voices are often associated with abnormal changes in aerodynamic parameters of subglottal pressure and airflow. Phonation instability pressure (PIP) has been previously proposed to evaluate subglottal pressure at the onset of chaotic phonation. We propose the concept of and measure phonation instability flow (PIF), the airflow at which phonation becomes chaotic. Phonation flow range (PFR), PIF minus phonation threshold flow (PTF), is proposed to assess the range over which normal vocal fold vibration occurs.
Repeated measures with each ex vivo larynx serving as its own control.
Pressure and airflow were measured at phonation onset and chaos onset in seven excised canine larynges under three experimental conditions: 0% elongation with no glottal gap; 20% elongation with no glottal gap; 20% elongation with a 3 mm posterior glottal gap. Paired t-tests were performed to determine if experimental measurements differed between elongations (0% and 20%) or degrees of abduction (20% elongation with and without a 3 mm glottal gap).
Both PIF and PFR were dependent on abduction but not elongation. PIP was not significantly dependent on either condition. PIF and PFR showed greater differences for abduction than either phonation threshold pressure (PTP) or PTF.
PIF and PFR may be useful parameters in the experimental or clinical settings, particularly when evaluating disorders characterized by a glottal gap such as vocal fold paralysis and presbylaryngis.
phonation instability flow; phonation flow range; phonation instability pressure; phonation threshold flow; subglottal pressure; excised larynx
To investigate the effect of vocal fold injury location on vibratory amplitude and lateral phase difference.
Repeated measures with each excised canine larynx serving as own control.
Basic science study conducted in university laboratory.
Vocal fold vibration of excised canine larynges was recorded with a high speed camera before and after inducing vocal fold injury at one of five locations: anterior, middle, posterior, medial, or superior. Medial and superior injuries were created within the middle third of the vocal fold. Five larynges were used for each of the five injury locations. Kymography was performed at the midpoint of the vocal folds for each video. Pre- and post-injury vibratory amplitude and lateral phase difference were compared for each location.
The anterior and medial injuries produced consistent decreases in vibratory amplitude. Middle and posterior injuries may slightly decrease amplitude. Superior injuries seemed to have no effect on amplitude. Anterior and medial injuries induce phase asymmetry between the right and left vocal folds. Middle injuries appeared to affect phase difference slightly, whereas posterior and superior injuries had no effect.
Injury to the anterior or medial portions of the vocal fold may be most likely to cause abnormal vocal fold vibration. Using caution in these locations during phonosurgery may favor superior post-operative vocal outcomes.
vocal fold scarring; videokymography; mucosal wave; vibratory amplitude; phase difference
We present an algorithm developed in MATLAB which can be applied to both normal and disordered swallowing to automatically extract a wide array of measurements from the spatiotemporal plots produced by high resolution manometry (HRM) of the pharyngeal swallow. The algorithm was developed from data from twelve normal and three disordered subjects swallowing 5 ml water boluses. Automated extraction was compared to manual extraction for a subset of seven normal and the three disordered subjects to evaluate algorithm accuracy. Area and line integrals, pressure wave velocity, and pressure gradients during upper esophageal sphincter opening were also measured. Automated extraction showed strong correlations with manual extraction, producing high correlation coefficients in both normal and disordered subjects for maximum velopharyngeal pressure and maximum tongue base pressure. Timing data were also strongly correlated for all variables, including velopharyngeal pressure duration, tongue base pressure duration, and total swallow duration. Preliminary descriptive data on area and line integrals are presented. Our results indicate that the algorithm can effectively extract data automatically from HRM spatiotemporal plots. The efficiency of the algorithm makes it a valuable tool to supplement clinical and research use of HRM.
pharyngeal manometry; high-resolution manometry; automated analysis; deglutition; deglutition disorders
The purpose of this study was to present a new procedure to treat symptomatic conjunctivochalasis (CCh) and to evaluate its efficacy. Forty-two patients with symptomatic CCh refractory to medical management were included on this study. Twenty-two patients (n = 32, eyes; n = 14 women and n = 8 men) underwent the new electrocoagulation procedure (Group I). Twenty patients (n = 27 eyes; n = 11 women and n = 9 men) underwent crescent-shaped conjunctiva resection (Group II). Ocular Surface Disease Index (OSDI) was used to evaluate ocular symptoms. There was a significant difference in mean and SD operation time between Group I (8.67 ± 2.07 minutes) and Group II (20.45 ± 3.98 minutes; P < 0.0001). OSDI scores (mean ± SD) were significantly lower in Group I (28.38 ± 3.14) than Group II (31.62 ± 3.17) at postoperative week 2 (P = 0.0004). No differences in OSDI scores were found between the 2 groups at postoperative week 4 (P = 0.1749) or 8 (P = 0.1483). OSDI scores were significantly lower at postoperative week 8 than at baseline in both Group I (P = 0.0002) and Group II (P = 0.0011). Electrocoagulation of the conjunctiva can successfully treat symptomatic CCh with earlier symptomatic attenuation and less operation time than traditional conjunctiva resection.
Conjunctivochalasis; Electrocoagulation; Conjunctiva
Extracellular microenvironments play crucial roles in modulating cell interactions during development. Here we discover that a conserved protein modification (O-glycosylation) influences extracellular matrix (ECM) composition during mammalian organogenesis, affecting integrin signaling and FGF-mediated cell proliferation. Specifically, mice deficient for an enzyme (Galnt1) that adds sugars to proteins during early stages of organogenesis resulted in intracellular accumulation of major basement membrane (BM) proteins and ER stress, with resultant effects on FGF signaling, epithelial cell proliferation and organ growth. Exogenous addition of BM components rescued FGF signaling and the growth defects in a β1-integrindependent manner. Our work demonstrates for the first time that O-glycosylation influences the composition of the ECM during mammalian organ development, influencing specific aspects of the ER stress response, cell signaling, cell proliferation and organ growth. Our work provides insight into the role of this conserved protein modification in both development and disease.
basement membrane; extracellular matrix; FGF signaling; integrin; ER stress; O-glycosylation; protein glycosylation; microenvironment; submandibular gland; development
A 58-year-old man presented with a six-month history of intermittent blood-stained posterior nasal discharge. Five years ago, he had a three-week episode of fitful light headaches. Nasal ventilation, olfactory sensation, and facial sensation were normal; there were no ophthalmological complaints. Coronal computed tomography (CT) scans revealed soft masses in the bilateral sphenoid sinuses with bone absorption. The patient underwent bilateral functional endoscopic sinus surgery and resection of right nasal papillary masses. Papillary masses and mucosa in both sphenoid sinuses were also removed. The mass in the left sphenoid sinus was diagnosed as two separate entities, one being a primary monophasic epithelial synovial sarcoma and the other an inverted papilloma, while the mass in the right sphenoid sinus was an inverted papilloma. After surgery, the patient underwent radiotherapy and chemotherapy. At the 50-month follow-up visit, there were no signs of recurrence.
We present three methods of performing pattern recognition on spatiotemporal plots produced by pharyngeal high-resolution manometry (HRM).
Classification models, including the artificial neural networks (ANNs) multilayer perceptron (MLP) and learning vector quantization (LVQ), as well as support vector machines (SVM), were evaluated for their ability to identify disordered swallowing. Data were collected from twelve normal and thirteen disordered subjects swallowing 5 ml water boluses. Following extraction of relevant parameters, a subset of the data was used to train the models and the remaining swallows were then independently classified by the networks.
All methods produced high average classification accuracies, with MLP, SVM, and LVQ achieving accuracies of 96.44%, 91.03%, and 85.39% respectively. When evaluating the individual contributions of each parameter and groups of parameters to the classification accuracy, parameters pertaining to the upper esophageal sphincter were most valuable.
Classification models show high accuracy in segregating HRM data sets and represent one method of facilitating application of HRM to the clinical setting by eliminating the time required for some aspects of data extraction and interpretation.
artificial neural network; classification model; pharyngeal manometry; high-resolution manometry; deglutition; dysphagia
To determine the effect of bolus volume on pharyngeal swallowing using high resolution manometry (HRM).
Repeated measures with subjects serving as own controls.
Twelve subjects swallowed four bolus volumes in the neutral head position: saliva; 5 ml water; 10 ml water; and 20 ml water. Pressure measurements were taken along the length of the pharynx using a high resolution manometer, with emphasis placed on the velopharynx, tongue base, and upper esophageal sphincter (UES). Variables were analyzed across bolus volumes using three-way repeated measures analysis of co-variance (ANCOVA) investigating the effect of sex, bolus volume, and pharynx length. Pearson’s product moment tests were performed to evaluate how pharyngeal pressure and timing events changed across bolus volume.
Velopharyngeal duration, maximum tongue base pressure, tongue base pressure rise rate, UES opening duration, and total swallow duration varied significantly across bolus volume. Sex did not have an effect, while pharynx length appeared to affect tongue base pressure duration. Maximum velopharyngeal pressure and minimum UES pressure had a direct relationship with bolus volume, while maximum tongue base pressure had an inverse relationship. Velopharyngeal pressure duration, UES opening duration, and total swallow duration increased as bolus volume increased.
Differences in pharyngeal pressures and timing of key pressure events were detected across varying bolus volumes. Knowing the relationships between bolus volume and pharyngeal pressure activity can be valuable when diagnosing and treating dysphagic patients.
Level of evidence
Pharyngeal pressure; bolus volume; high-resolution manometry; swallowing physiology; deglutition
Maternal race/ethnicity, age, and socioeconomic status (SES) are important factors determining birth outcome. Previous studies have demonstrated that, teenagers, and mothers with advanced maternal age (AMA), and Black/Non-Hispanic race/ethnicity can independently increase the risk for a poor pregnancy outcome. Similarly, public insurance has been associated with suboptimal health outcomes. The interaction and impact on the risk of a pregnancy resulting in a NICU admission has not been studied. Our aim was, to analyze the simultaneous interactions of teen/advanced maternal age (AMA), race/ethnicity and socioeconomic status on the odds of NICU admission.
The Consortium of Safe Labor Database (subset of n = 167,160 live births) was used to determine NICU admission and maternal factors: age, race/ethnicity, insurance, previous c-section, and gestational age.
AMA mothers were more likely than teenaged mothers to have a pregnancy result in a NICU admission. Black/Non-Hispanic mothers with private insurance had increased odds for NICU admission. This is in contrast to the lower odds of NICU admission seen with Hispanic and White/Non-Hispanic pregnancies with private insurance.
Private insurance is protective against a pregnancy resulting in a NICU admission for Hispanic and White/Non-Hispanic mothers, but not for Black/Non-Hispanic mothers. The health disparity seen between Black and White/Non-Hispanics for the risk of NICU admission is most evident among pregnancies covered by private insurance. These study findings demonstrate that adverse pregnancy outcomes are mitigated differently across race, maternal age, and insurance status.
There are limited data on fluoroquinolone resistance and its impact on mortality in cases of E. coli bloodstream infection (BSI).
To determine risk factors for in-hospital mortality among patients with E. coli BSIs.
A retrospective case-control study
A 1250-bed tertiary academic medical center
Patients with fluoroquinolone-resistant E. coli BSI from January 1, 2000 through December 31, 2005 with 1:1 matched control patients with fluoro-quinolone sensitive E. coli BSI.
A total of 93 cases and 93 control patients were included. Compared to control patients, cases were more likely to be admitted from a long term care facility (35% vs. 9%; p<0.001) and to have a hospital-acquired bacteremia (54% vs. 33%; p=0.008). Crude mortality was 26% for cases and 8% for controls (p=0.002). On univariate analysis, predictors for in-hospital mortality included female gender, admission from a long term care facility, APACHE II score >10, Charlson comorbidity score >4, cardiac dysfunction, cirrhosis, renal dysfunction, treatment with corticosteroids, and a fluoroquinolone-resistant E. coli bacteremia. On multivariate analysis, independent risk factors for in-hospital mortality were cirrhosis [adjusted Odds Ratio (aOR) 7.2; CI (1.7, 29.8); p=0.007], cardiac dysfunction [aOR 3.9; CI (1.6, 9.4); p=0.003), and infection with a fluoroquinolone-resistant E. coli isolate [aOR 3.9; CI (1.5, 10.2); p=0.005].
After controlling for severity of illness and multiple comorbidities only fluoroquinolone resistance, cirrhosis, and cardiac dysfunction independently predicted mortality in patients with E. coli bacteremia.
Escherichia coli; bacteremia; fluoroquinolone; resistance; mortality
Salivary gland organogenesis involves the specification, maintenance, lineage commitment, and differentiation of epithelial stem/progenitor cells. Identifying how stem/progenitor cells are directed along a series of cell fate decisions to form a functional salivary gland will be necessary for future stem cell regenerative therapy. The identification of stem/progenitor cells within the salivary gland has focused on their role in postnatal glands and little is known about them in embryonic glands. Here, we have reviewed the information available for other developing organ systems and used it to determine whether similar cell populations exist in the mouse submandibular gland. Additionally, using growth factors that influence salivary gland epithelial morphogenesis during development, we have taken a simple experimental approach asking whether any of these growth factors influence early developmental lineages within the salivary epithelium on a transcriptional level. These preliminary findings show that salivary epithelial stem/progenitor populations exist within the gland, and that growth factors that are reported to control epithelial morphogenesis may also impact cell fate decisions. Further investigation of the signaling networks that influence stem/progenitor cell behavior will allow us to hypothesize how we might induce autologous stem cells to regenerate damaged salivary tissue in a therapeutic context.
Epithelial-mesenchyme interactions during organogenesis are regulated by dynamic and reciprocal interactions between growth factors and extracellular matrix (ECM) components. Mouse embryonic submandibular gland (SMG) epithelium, isolated from its endogenous mesenchyme, undergoes branching morphogenesis when cultured ex vivo in a basement membrane extract in serum-free medium with growth factor stimulation. The resulting three-dimensional epithelial morphogenesis in the defined culture system makes this a useful model to analyze cell-cell and cell-matrix interactions, growth factor-mediated signaling and gene expression, proliferation, apoptosis, migration, lumen formation, and epithelial morphogenesis in a primary organ culture system. SMG epithelial culture is robust, reproducible, uses small amounts of reagents, and changes in gene expression are measured by real-time PCR using a limited amount of embryonic tissue. In this chapter, we describe a detailed protocol for isolating primary embryonic SMG epithelium and setting up an ECM and growth factor-dependent, serum-free assay of epithelial morphogenesis, with subsequent analysis of gene expression by real-time PCR.
ECM; laminin; submandibular gland; FGF10; branching morphogenesis; FGFR signaling
An irreversible loss of salivary gland function often occurs in humans after removal of salivary tumors, after therapeutic radiation of head and neck tumors, as a result of Sjögren’s syndrome, and in genetic syndromes affecting gland development. The permanent loss of gland function impairs the oral health of these patients and broadly affects their quality of life. The regeneration of functional salivary gland tissue is thus an important therapeutic goal for the field of regenerative medicine and will likely involve stem/progenitor cell biology and/or tissue engineering approaches. Recent reports demonstrate how both innervation of the salivary gland epithelium and certain growth factors influence progenitor cell growth during mouse salivary gland development. These advances in our understanding suggest that developmental mechanisms of mouse salivary gland development may provide a paradigm for postnatal regeneration of both mice and human salivary glands. Here, we will discuss the developmental mechanisms that influence progenitor cell biology and the implications for salivary gland regeneration.
To assess the efficacy of obstetric maneuvers for resolving shoulder dystocia, and the effect that these maneuvers have on neonatal injury when shoulder dystocia occurs.
Using an electronic database encompassing 206,969 deliveries, we identified all women with a vertex fetus beyond 34 0/7 weeks of gestation who incurred a shoulder dystocia during the process of delivery. Women whose fetuses had a congenital anomaly and women with an antepartum stillbirth were excluded. Medical records of all cases were reviewed by trained abstractors. Cases involving neonatal injury (defined as brachial plexus injury, clavicular or humerus fracture, or hypoxic ischemic encephalopathy or intrapartum neonatal death attributed to the shoulder dystocia) were compared to those without injury.
Among 132,098 women who delivered a term cephalic liveborn fetus vaginally, 2,018 incurred a shoulder dystocia (1.5%), and 101 (5.2%) of these incurred a neonatal injury. Delivery of the posterior shoulder was associated with the highest rate of delivery when compared to other maneuvers (84.4% compared with 24.3% to 72.0% for other maneuvers; P<.005 to P<.001) and similar rates of neonatal injury (8.4% compared with 6.1% to 14.0%; P=.23 to P=.7). The total number of maneuvers performed significantly correlated with the rate of neonatal injury (P<.001).
Delivery of the posterior shoulder should be considered following McRoberts maneuver and suprapubic pressure in the management of shoulder dystocia. The need for additional maneuvers was associated with higher rates of neonatal injury.
To directly compare the mechanical and labial interruption techniques of measuring subglottal pressure (Ps), mean flow rate (MFR) and laryngeal resistance (RL).
Thirty-four subjects performed 10 trials with both mechanical and labial interruption. Ps and MFR were recorded while RL was calculated by dividing Ps by MFR. Coefficients of variation were calculated in order to compare intra-subject precision. A subset of 10 subjects performed the tasks twice with thirty minutes between sessions. Bland-Altman plots were used to determine intra-subject repeatability for each of the methods.
Mechanical interruption produced coefficients of variation for Ps, MFR, and RL of 0.0995, 0.127 and 0.129 respectively. Labial interruption produced coefficients of variation of 0.102, 0.147 and 0.169 respectively. P-values were 0.824 for Ps, 0.159 for MFR and 0.043 for RL. The Bland-Altman plots revealed comparable repeatability between the two methods. The 95% confidence intervals of the Bland-Altman plots for mechanical interruption were (-0.050 to 0.072), (-0.543 to 1.832), and (-2.498 to 10.528) for MFR, Ps, and RL. Confidence intervals for labial interruption were (-0.018 to 0.031), (0.057 to 2.442), and (-3.267 to 10.595) for MFR, Ps, and RL.
Mechanical interruption produced higher precision when measuring RL due to more reliable airflow measurements. Mechanical and labial interruption showed comparable repeatability. Further research into using mechanical interruption clinically is warranted.
Lasers are a relatively recent addition to laryngeal surgery. Since their invention, laser use and applications have expanded rapidly. In this paper, we discuss the benefits and disadvantages of lasers for different procedures, as well as ways to overcome commonly faced clinical problems. The use of lasers in surgery has offered a time- and cost-efficient alternative to cold surgical techniques, and has been employed in the treatment of numerous laryngeal pathologies, including stenoses, recurrent respiratory papillomatosis, leukoplakia, nodules, malignant laryngeal disease, and polypoid degeneration (Reinke’s edema). However, lasers can incur adjacent tissue damage and vocal fold scarring. These problems can be minimized through understanding the mechanisms by which lasers function and correctly manipulating the parameters under a surgeon’s control. By varying fluence, power density, and pulsation, tissue damage can be decreased and lasers can be used with greater confidence. The various types of lasers and their applications to the treatment of specific pathologies are reviewed with the intention of helping surgeons select the best tool for a given procedure. Recent applications of lasers to treat benign laryngeal lesions and severe laryngomalacia demonstrate that additional research must be conducted in order to realize the full potential of this surgical tool.
Laser; laryngeal surgery; phonosurgery
We present the adjustable balloon implant (ABI), a novel implant to be used in type I thyroplasty for the treatment of vocal fold paralysis. The ABI offers the same medialization provided by other implants, but can easily be catered to individual patient anatomy as well as modified postoperatively without the need for a revision thyroplasty.
Repeated measures with each larynx serving as its own control.
Medialization thyroplasty (MT) with the ABI was performed on five excised canine larynges. Mucosal wave, aerodynamic, and acoustic parameters were measured for three conditions: normal; right vocal fold paralysis; and paralysis with the ABI.
Insertion of the ABI resulted in significant decreases in both phonation threshold pressure and phonation threshold flow. Perturbation parameters of percent jitter and percent shimmer were also significantly decreased and restored to normal levels. Signal-to-noise ratio was significantly increased to the normal level as well. The mucosal wave was preserved after implant insertion.
This preliminary experiment showing significant improvements in aerodynamic and acoustic parameters demonstrates the potential of the ABI as a thyroplasty implant. Effective medialization and preservation of the mucosal wave combined with post-operative adjustability makes it a potentially valuable clinical device.
Evidence based medicine level
Not applicable – basic science study on excised animal tissue.
Adjustable balloon implant; medialization thyroplasty; vocal fold paralysis
Vocal fold vibration is associated with four distinct vibratory patterns: those of the right-upper, right-lower, left-upper, and left-lower vocal fold lips. The purpose of this study was to propose a least squares method to quantify the vibratory properties of each of the four vocal fold lips via videokymography (VKG).
This was a methodological study designed to examine the impact of subglottal pressure and line-scan position on mucosal wave parameters.
VKG, a line-scan imaging technique, has proven to be an effective method for studying vocal fold vibratory patterns. This study used VKG images and an automatic mucosal wave extraction method to examine the vibration of each individual vocal fold lip of 17 excised canine larynges under differing subglottal pressures and line-scan positions.
Varying subglottal pressure led to results consistent with previous studies. Examination of the vocal folds at different line-scan positions along its length revealed that amplitude is greatest at the midpoint of the vocal fold, followed by the anterior portion of the vocal fold, with the posterior portion having the lowest amplitude (P < .001). Frequency and phase delay did not change significantly throughout the length of the vocal fold.
The method used in this study allows for easy determination of four sets of vibratory parameters, and examination of the effect of biomechanical parameters on vocal fold vibrations.
Videokymography; mucosal wave; subglottal pressure; line-scan position
The optimal degree of arytenoid rotation for arytenoid adduction (AA) can be determined using quantitative real-time voice analysis.
Repeated measures with each larynx serving as its own control.
Unilateral vocal fold paralysis (VFP) was modeled in five excised canine larynges. Medialization laryngoplasty (ML) was performed, followed by AA. The optimal degree of arytenoid rotation was determined using real-time measurements of vocal efficiency (VE), percent jitter, and percent shimmer. After the optimal degree of rotation was determined, the arytenoid was hypo- and hyper-rotated 10±2% of the optimal angle to mimic hypoadducted and hyperadducted states. Aerodynamic, acoustic, and mucosal wave measurements were recorded.
Mean optimal angle of arytenoid adduction was 151.4 ± 2.5°. VE differed significantly across experimental conditions (p = 0.003). Optimal AA produced the highest VE of any treatment, but this value did not reach that produced in the normal condition. Percent jitter (p < 0.001) and percent shimmer (p < 0.001) differed across groups and were lowest for optimal AA. Mucosal wave amplitude of the normal (p = 0.001) and paralyzed fold (p = 0.043) differed across treatments. Amplitude of both folds was highest for optimal AA.
VE and perturbation parameters were sensitive to the degree of arytenoid rotation. Using real-time voice analysis may aid surgeons in determining the optimal degree of arytenoid rotation when performing AA. Testing this method in patients and determining if optimal vocal outcomes are associated with optimal respiratory and swallowing outcomes will be essential to establishing clinical viability.
Evidence based medicine level
Not applicable – excised animal tissue study.
arytenoid adduction; vocal fold paralysis; medialization laryngoplasty; laryngeal framework surgery
Our investigations have identified a mechanism by which exogenous production of nitric oxide (NO) induces resistance of Gram-positive and -negative bacteria to aminoglycosides. An NO donor was found to protect Salmonella spp. against structurally diverse classes of aminoglycosides of the 4,6-disubstituted 2-deoxystreptamine group. Likewise, NO generated enzymatically by inducible NO synthase of gamma interferon-primed macrophages protected intracellular Salmonella against the cytotoxicity of gentamicin. NO levels that elicited protection against aminoglycosides repressed Salmonella respiratory activity. NO nitrosylated terminal quinol cytochrome oxidases, without exerting long-lasting inhibition of NADH dehydrogenases of the electron transport chain. The NO-mediated repression of respiratory activity blocked both energy-dependent phases I and II of aminoglycoside uptake but not the initial electrostatic interaction of the drug with the bacterial cell envelope. As seen in Salmonella, the NO-dependent inhibition of the electron transport chain also afforded aminoglycoside resistance to the clinically important pathogens Pseudomonas aeruginosa and Staphylococcus aureus. Together, these findings provide evidence for a model in which repression of aerobic respiration by NO fluxes associated with host inflammatory responses can reduce drug uptake, thus promoting resistance to several members of the aminoglycoside family in phylogenetically diverse bacteria.
To describe contemporary cesarean delivery practice in the U.S.
Consortium on Safe Labor collected detailed labor and delivery information from 228,668 electronic medical records from 19 hospitals across the U.S., 2002 – 2008.
The overall cesarean delivery rate was 30.5%. 31.2% of nulliparas were delivered by cesarean section. Prelabor repeat cesarean delivery due to a previous uterine scar contributed 30.9% of all cesarean sections. 28.8% of women with a uterine scar had a trial of labor and the success rate was 57.1%. 43.8% women attempting vaginal delivery had induction. Half of cesarean for dystocia in induced labor were performed before 6 cm of cervical dilation.
To decrease cesarean delivery rate in the U.S., reducing primary cesarean delivery is the key. Increasing VBAC rate is urgently needed. Cesarean section for dystocia should be avoided before the active phase is established, particularly in nulliparas and in induced labor.
cesarean delivery; induction; labor; VBAC