Cross-linked hydrogel and polyester resorbable ventilation tubes in a Chinchilla model

OBJECTIVES/HYPOTHESIS

To determine the resorption rate and biocompatibility characteristics of novel cross-linked hydrogel ventilation tubes and varied formulations of polyester ventilation tubes in a Chinchilla model.

STUDY DESIGN

Animal Study.

METHODS

Three cross-linked glycosaminoglycan hydrogel ventilation tubes fabricated by cross-linking thiol-modified chondroitin sulfate or thiol-modified carboxymethylated hyaluronic acid, four different polyester ventilation tubes (poly L-lactide [PLA], 50/50 poly D,L-lactide-co-glycolide [PLGA], and silver-impregnated versions of PLA and PLGA tubes) were placed into the tympanic membranes of chinchillas. Commercially available fluoroplastic ventilation tubes were placed in the contralateral ear of each animal to serve as a control. Integrity of the tubes was assessed by weekly otoscopy. Biocompatibility was assessed by auditory brainstem response, by otoscopic and histologic examination of the tympanic membrane at the tube site.

RESULTS

The hydrogel tubes had very short resorption times that expanded and enlarged the myringotomy site. PLGA and silver-coated PLGA tubes maintained their integrity in the tympanic membrane for similar durations of 18.9 ± 6.4 days and 21.0 ± 6.0 days, respectively. The silver-coated PLGA tubes had lower neutrophil and fibrosis scores than PLGA tubes. PLA tubes demonstrated equivalent findings to commercially available nonresorbable tubes with respect to otoscopic findings, auditory brainstem response thresholds, and histologic inflammatory scores.

CONCLUSIONS

Resorbable polyester pressure equalization tubes demonstrate predictable resorption behavior and similar biocompatibility characteristics when compared with nonresorbable tubes. Silver modification may confer some stability to PLGA tubes. Hydrogel tubes have very short resorption times, tend to enlarge the myringotomy site, and show greater inflammatory changes.

Calcium hydroxyapatite fillers

Calcium hydroxyapatite fillers have unique advantages over other fillers in regards to duration of action and volume of product required for augmentation, especially in the midface and lower face. In this article, we describe our experience with calcium hydroxyapatite fillers and compare them with other available filler products.

Validation of the cell cycle G(2) delay assay in assessing ionizing radiation sensitivity and breast cancer risk

Genetic variations in cell cycle checkpoints and DNA repair genes are associated with prolonged cell cycle G(2) delay following ionizing radiation (IR) treatment and breast cancer risk. However, different studies reported conflicting results examining the association between post-IR cell cycle delay and breast cancer risk utilizing four different parameters: cell cycle G(2) delay index, %G(2)-M, G(2)/G(0)-G(1), and (G(2)/G(0)-G(1))/S. Therefore, we evaluated whether different parameters may influence study results using a data set from 118 breast cancer cases and 225 controls as well as lymphoblastoid and breast cancer cell lines with different genetic defects. Our results suggest that cell cycle G(2) delay index may serve as the best parameter in assessing breast cancer risk, genetic regulation of IR-sensitivity, and mutations of ataxia telangiectasia mutated (ATM) and TP53. Cell cycle delay in 21 lymphoblastoid cell lines derived from BRCA1 mutation carriers was not different from that in controls. We also showed that IR-induced DNA-damage signaling, as measured by phosphorylation of H2AX on serine 139 (γ-H2AX) was inversely associated with cell cycle G(2) delay index. In summary, the cellular responses to IR are extremely complex; mutations or genetic variations in DNA damage signaling, cell cycle checkpoints, and DNA repair contribute to cell cycle G(2) delay and breast cancer risk. The cell cycle G(2) delay assay characterized in this study may help identify subpopulations with elevated risk of breast cancer or susceptibility to adverse effects in normal tissue following radiotherapy.

Laryngopharyngeal Abnormalities in Hospitalized Patients With Dysphagia

OBJECTIVES

To determine the prevalence of laryngopharyngeal (LP) abnormalities in hospitalized patients with dysphagia referred for flexible endoscopic evaluation of swallowing (FEES).

STUDY DESIGN

Retrospective, blinded review by two otolaryngologists of 100 consecutive FEES studies performed and video-recorded by a speech-language pathologist (SLP).

METHODS

Two otolaryngologists reviewed videos of 100 consecutive FEES studies on hospitalized patients with dysphagia for the presence of abnormal LP findings.

RESULTS

Sixty-one male and 38 female patients comprised the hospital dysphagia cohort. The mean age was 62. One subject could not be evaluated because of the severity of the retained secretions, leaving 99 subjects in the cohort. Seventy-six percent had been previously intubated, with a mean intubation duration of 13 days. The overall prevalence of abnormal LP findings was 79%. Forty-five percent of the patients presented with two or more findings, which included arytenoid edema (33%), granuloma (31%), vocal fold paresis (24%), mucosal lesions (17%), vocal fold bowing (14%), diffuse edema (11%), airway stenosis (3%), and ulcer (6%). There was a significant difference in LP findings between those individuals who had or had not been intubated.

CONCLUSIONS

Hospitalized patients with dysphagia are at high risk for LP abnormalities, particularly if they have been intubated, and may benefit from either 1) an initial joint examination by the SLP and otolaryngologist or 2) an otolaryngologist's review of the recorded examination conducted by the SLP. Such otolaryngology involvement could identify airway stenosis patients at an earlier stage, initiate granuloma treatment sooner, enable earlier biopsy of unexpected lesions, and allow follow-up of mucosal and neuromuscular findings that do not respond to medical management.

The effects of smoking on estradiol metabolism

Smoking remains a major health problem especially among women and it influences estrogen metabolism and the risk for multiple estrogen sensitive outcomes. Many indirect effects of smoking exist through the ability of the by-products to modify a variety of drugs, enzymes, and hormones. The results of several in vitro studies have shown that constituents of cigarette smoke have significant effects on production and metabolism of estrogens. In some cases, such as osteoporosis and endometrial cancer, smoking appears to attenuate the effects of estrogen. However, for other outcomes such as breast cancer, venous thromboembolic events (VTE), and coronary heart disease (CHD), the relationship between smoking and estrogen exposure is less defined. Based on the preponderance of evidence, smokers are likely to require higher doses of hormone replacement therapy (HRT) to achieve comparable clinical effect to that observed in nonsmokers. However, uptitrating the dose of HRT in smokers to achieve a desired systemic level or clinical response may simultaneously increase risk for adverse effects that are primarily driven by hepatic rather than systemic exposure. The healthy benefits from smoking cessation should be expressed to women who choose to use HRT, and every effort should be made to encourage them to stop smoking so that they can be effectively treated with the lowest possible dose of HRT.