The effect of using citric or acetic acid on survival of Listeria monocytogenes during fish protein recovery by isoelectric solubilization and precipitation process.

Isoelectric solubilization and precipitation (ISP) is a protein recovery process effective at reducing Listeria innocua, a nonpathogenic bacterium typically used as a surrogate for L. monocytogenes in recovered trout protein. The response of L. monocytogenes to ISP processing was determined and compared to the response of L. innocua. Headed and gutted rainbow trout were inoculated with L. monocytogenes (10.16 log CFU/g), homogenized, and pH-adjusted with granular citric acid (pH 2.0 and 2.5) or glacial acetic acid (pH 3.0 and 3.5). Proteins were solubilized and centrifugation was used to remove insoluble components (skin, insoluble protein, so on). The supernatant was returned to the protein isoelectric point (pH 5.5) with NaOH and centrifuged to remove precipitated protein. Microbial load was enumerated on both growth and selective media; recovery was not significantly different (P > 0.05). Surviving cells from each component (protein, insoluble, and water) were compared to initial inoculum numbers. Significant reductions were detected at all pH (P < 0.05). The greatest reductions were at pH 3.0 with acetic acid, with a mean log reduction of 3.03 in the combined components, and a 3.53 log reduction in the protein portion. Data were compared to results from a previous study using L. innocua. Significant differences (P < 0.05) in recovery were found between the 2 species at pH 2.0 and 3.0 with greater recovery of L. monocytogenes, regardless of processing pH or acid type. These results demonstrate the variability in resistance between species and indicate that L. innocua is not an appropriate surrogate for L. monocytogenes for ISP processing with organic acids.

Survival of Listeria innocua in rainbow trout protein recovered by isoelectric solubilization and precipitation with acetic and citric acids.

During mechanical fish processing, a substantial amount of protein is discarded as by-products. Isoelectric solubilization and precipitation (ISP) is a process that uses extreme pH shifts to solubilize and precipitate protein from by-products to recover previously discarded protein. Typically, strong acids are used for pH reduction, but these acids do not have a pasteurization effect (6 log reduction) on bacterial load; therefore, organic acids were used during ISP processing to test the impact on Listeria innocua concentrations. Headed and gutted rainbow trout (Oncorhynchus mykiss) were inoculated with L. innocua, homogenized, and brought to the target pH with granular citric acid (pH 2.0 and 2.5) or glacial acetic acid (pH 3.0 and 3.5). Proteins were solubilized for 10 min at 4°C, and insoluble components (e.g., skin and insoluble protein) were removed by centrifugation. The remaining solution was pH shifted to the protein isoelectric point (pH 5.5) with sodium hydroxide, and precipitated protein was separated from the water. Microbial cells for each component (proteins, insolubles, and water) were enumerated on modified Oxford agar (MOX) and tryptic soy agar with 6% yeast extract (TSAYE). The sums of the surviving cells from each component were compared with the initial inoculum levels. No significant differences were observed between results obtained from TSAYE and from MOX (P > 0.05). Significant reductions in microbial populations were detected, regardless of pH or acid type (P < 0.05). The greatest reduction was at pH 3.0 with glacial acetic acid, resulting in a mean reduction of 6.41 log CFU/g in the recovered protein and 5.88 log CFU/g in the combined components. These results demonstrate the antimicrobial potential of organic acids in ISP processing.

Induced telomerase activity in primary aortic endothelial cells by low-LET gamma-radiation is mediated through NF-kappaB activation.

Our objective was to understand the mechanism through which cells that initially survive irradiation could acquire survival advantage. In this study, we show evidence that low-linear energy transfer gamma-radiation can induce telomerase enzyme activity in primary aortic endothelial cells, and that an upstream regulator, nuclear factor kappa B (NF-kappaB), controls this activation. Telomeric repeat amplification protocol (TRAP) assay showed that cells exposed to a dose of 2 Gy induce telomerase activity. Subsequent analysis revealed that radiation-induced telomeric activity is regulated at the transcriptional level by triggering activation of the promoter of the telomerase catalytic subunit, telomerase reverse transcriptase (TERT). A mechanistic study revealed that NF-kappaB becomes functionally activated upon radiation exposure and mediates the upregulation of telomerase activity by binding to the kappaB-binding region in the promoter region of the TERT gene. More significantly, elimination of the NF-small ka, CyrillicB recognition site on the telomerase promoter or inhibition of NF-small ka, CyrillicB by ectopically expressing the inhibitor protein IkappaBalpha mutant (Ismall ka, CyrillicBalpha(S32A/S36A))) compromises radiation-induced telomerase promoter activation. Consistent with the notion that NF-kappaB mediates gamma-ray-induced telomerase responses, TRAP assay revealed that ectopically expressed IkappaBalpha(S32A/S36A)) also attenuated telomerase enzyme activity. These findings indicate that NF-kappaB activation following ionizing radiation exposure may elicit a survival advantage by upregulating and maintaining telomerase activity.

Postoperative management of pediatric tracheostomy: results of a nationwide survey.

OBJECTIVE: A survey was undertaken to document the postoperative care of pediatric tracheostomies by otolaryngologists. STUDY DESIGN: This study represents the results of a national survey of 564 otolaryngologists covering a broad scope of postoperative pediatric tracheostomy issues considered for patients younger than 2 years and patients older than 5 years. RESULTS: Of the surveys sent, 134 responses were received, portraying a certain standard management scheme that seems to be used by most respondents. CONCLUSIONS: Very little difference was seen in respondents' management of patients younger than 2 years of age as compared with those who are older than 5 years. Furthermore, agreement between actual practice and published recommendations seems to vary with some management issues. The results of this study provide a means by which otolaryngologists may familiarize themselves with national trends in the postoperative management of pediatric tracheostomies.

Securing meshed split-thickness skin grafts with 2-octylcyanoacrylate.

Meshed split-thickness skin grafts (STSGs) secured with 2-octylcyanoacrylate (2-OCA) were compared with meshed STSGs secured by suture and bolster (S&B). The 2 techniques were compared for graft survival, foreign-body giant cell response, inflammatory response, appearance, texture, and application time. Sixteen 2.5 x 2. 5 cm meshed STSGs were harvested from the dorsa of 2 pigs for a total of 32 grafts. On each pig 8 grafts were sprayed with 2-OCA, and the other 8 were secured with S&B. Evaluations were performed on postoperative days 14, 24, 48, and 56. Biopsy specimens were obtained on postoperative days 14 and 56. There were no significant differences in percent survival, foreign-body giant cell response, inflammatory response, and appearance between control and study grafts. The average time to apply the 2-OCA onto a graft was 3 seconds, compared with 8 minutes for S&B application. 2-OCA provides a quick and reliable means of securing meshed STSGs and would be especially useful in areas where it is difficult to use S&B, such as total maxillectomy defects.

Leiomyosarcoma of the larynx. Case report.

Leiomyosarcoma involving the larynx is extremely rare and may be difficult to diagnose. Likewise, because of the rarity of this lesion, little information exists with regard to long-term follow-up or optimal management. Reported here is a review of the literature and a case report of a patient with leiomyosarcoma of the larynx treated by surgery alone with 5 years of follow-up.

Disseminated zygomycosis due to Rhizopus schipperae after heatstroke.

A 21-year-old woman suffered heatstroke and developed diarrhea while trekking across south Texas. The heatstroke was complicated by seizures, rhabdomyolysis, pneumonia, renal failure, and disseminated intravascular coagulation. The patient's stool and blood cultures grew Campylobacter jejuni. The patient subsequently developed paranasal and gastrointestinal zygomycosis and required surgical debridement and a prolonged course of amphotericin B. The zygomycete cultured was Rhizopus schipperae. This is only the second isolate of R. schipperae that has been described. R. schipperae is characterized by the production of clusters of up to 10 sporangiophores arising from simple but well-developed rhizoids. These asexual reproductive propagules are produced on Czapek Dox agar but are absent on routine mycology media, where only chlamydospores are observed. Despite multiorgan failure, bacteremia, and disseminated zygomycosis, the patient survived and had a good neurological outcome. Heatstroke has not been previously described as a risk factor for the development of disseminated zygomycosis.

Fracture at fenestration of synthetic tracheostomy tube resulting in a tracheobronchial airway foreign body.

Tracheostomy tube fracture resulting in airway obstruction is a relatively rare but serious complication. We report the case of a 48-year-old man whose tracheostomy tube fractured and became lodged in the right primary bronchus. Recommendations are made for tracheostomy care to help prevent similar complications in patients with an indwelling tracheostomy tube.

Impact of a laryngectomy on quality of life: perspective of the patient versus that of the health care provider.

This study retrospectively assesses the impact of laryngectomy on the quality of life of 46 patients as compared to the perception of the impact of laryngectomy of 13 health care providers (HCPs). Employing the "time trade-off" methodology, we assessed patient and HCP preferences and calculated estimated utilities. We found that 20% of patients would be willing to compromise anticipated life expectancy to preserve voice or preoperative quality of life. By comparison, 46% of the HCPs perceived that their patients would be willing to accept a reduced life span in order to preserve their larynx and quality of life. In conclusion, the percentage of HCPs who believed their patients would compromise survival was substantially higher than the percentage of actual patients who expressed this preference. This perception may influence physicians' attitudes toward recommending laryngeal preservation therapy for their patients. For most laryngectomy patients, treatments attempting laryngeal preservation, particularly if associated with compromised survival, may not be warranted.

Motor innervation of the cricopharyngeus muscle by the recurrent laryngeal nerve.

Patients with recurrent laryngeal nerve (RLN) paresis demonstrate impaired function of laryngeal muscles and swallowing. The cricopharyngeus muscle (CPM) is a major component of the upper esophageal sphincter. It was hypothesized that the RLN innervates this muscle. A nerve branch leading from the RLN to the CPM was found in adult sheep by anatomic dissection. Electrical stimulation of the RLN elicited a muscle action potential recorded by electrodes placed in the ipsilateral CPM. Swallowing was investigated by mechanical stimulation of oropharynx pre- and postsectioning of the RLN. Severing of the RLN resulted in a loss of the early phases of swallow-related CPM electromyographic activity; however, late-phase CPM electromyographic activity persisted. The RLN provides motor innervation of the CPM, which also has innervation from the pharyngeal plexus.

Restoration of function in the paralyzed rabbit orbicularis oculi muscle by direct functional electrical stimulation.

Restoration of the ability to blink and protect the eye in the patient with facial paralysis remains a challenge. Although many treatments exist, no one approach corrects all the deficits associated with the loss of orbicularis oculi function. In this study, the author investigated the feasibility of restoring function by direct electrical stimulation of the paralyzed orbicularis oculi muscle in the rabbit model. Using a pacing device developed by the author, functional restoration of a normal-appearing blink was produced throughout 30 days of continuous pacing in six rabbits with transected facial nerves. Histologic evaluations of the paced tissues demonstrated no evidence of detrimental effects attributable to the electrical stimulation. The findings of this study support the feasibility of employing direct electrical stimulation to restore the function of paralyzed orbicularis oculi muscles. Potential applications may also exist in other areas in which peripheral denervation creates functional impairment.

Cocaine, lidocaine, tetracaine: which is best for topical nasal anesthesia?

The quality of nasal anesthesia obtained with three local anesthetic solutions (4% cocaine, 2% lidocaine in oxymetazoline, and 1% tetracaine in oxymetazoline) was evaluated in a randomized study. Each local anesthetic mixture was applied to the nasal septum of healthy volunteers using medication-soaked pledgets. Measurements of anesthetic effect (sensation threshold and pain perception) were made with Semmes-Weinstein monofilaments. Measurements were performed prior to local anesthetic application and 10 and 70 min after local anesthetic application. Subjects had greater increases in sensation threshold with tetracaine than with lidocaine or cocaine at both 10 and 70 min (P < 0.05). Subjects had greater decreases in pain perception with tetracaine than with lidocaine or cocaine at both time intervals (P < 0.05). Tetracaine mixed with oxymetazoline appears to be a superior topical anesthetic for nasal procedures.

Intranasal anesthetic effects of lidocaine and tetracaine compared.

The quality of nasal anesthesia obtained with two local anesthetic solutions (2% lidocaine in oxymetazoline and 1% tetracaine in oxymetazoline) was evaluated in this double-blind, randomized study. Each local anesthetic mixture was applied to the nasal septum of healthy volunteers with medication-soaked pledgets. Measurements of anesthetic effect (sensation threshold and pain perception) were made with Semmes-Weinstein monofilaments (North Coast Medical, San Jose, Calif.). Measurements were performed before local anesthetic application and at 10 and 70 minutes after local anesthetic application. Subjects had greater increases in sensation threshold with tetracaine than with lidocaine at both 10 and 70 minutes (p = 0.0005 and p = 0.0001, respectively). Subjects had greater decreases in pain perception with tetracaine than with lidocaine at both time intervals (p = 0.0003 and p < 0.0001, respectively). Tetracaine mixed with oxymetazoline appears to be a superior topical anesthetic for nasal procedures.

Cephalosporin antibiotics.

The last three decades have seen the emergence of a cornucopia of antimicrobials in the cephalosporin class. This becomes even more apparent when one realizes that over 60 pages of the 1993 AHFS drug information text is dedicated to the cephalosporin class. Due to similarities in nomenclature and the proliferation of available agents, the clinician is constantly challenged by this confusing array of antimicrobials. The intent of this manuscript will be to distill the volumes of information available on cephalosporins into a more manageable format and close with a summary of the most clinically important cephalosporin antimicrobials.

Respiratory muscle activities after birth in asphyxiated preterm lambs.

Laryngeal and pump muscle activities are important in the establishment and maintenance of functional residual capacity (FRC) after birth. The aim of this study was to determine the expiratory mechanisms by which laryngeal and diaphragmatic activities achieve the increments in FRC postnatally. Wire electrodes were placed in: the laryngeal abductor, a major laryngeal adductor, the inferior pharyngeal constrictor and the diaphragm of six fetal sheep. The lambs were delivered prematurely by cesarean section and a face mask with a pneumotachograph applied. A grunting respiratory pattern was characterized by severe expiratory airflow retardation, associated with laryngeal adductor activity. In grunting breaths, minimal volume loss at end-expiration and incremental increases in FRC occurred when the onset of diaphragmatic activity preceded the onset of laryngeal muscle activities associated with laryngeal opening. Thus the timing order of laryngeal and diaphragmatic muscle activities near end-expiration is a determinant of increments in FRC.

Anatomic considerations in complications of endoscopic and intranasal sinus surgery.

Complications of endoscopic and classic intranasal sinus surgery have been documented by case reports and large retrospective reviews. The most serious complications have involved violation of the intracranial space or orbit. Hemorrhage has also proven to be a significant cause of morbidity, either of itself, or by limiting visualization and thus contributing to other injuries. Although numerous studies have been performed to determine various anatomic relationships, relatively few have addressed relationships that use practical reference points easily accessible to the endoscopic or intranasal sinus surgeon. In an effort to reduce the risk of complications such as blindness, orbital hematoma, and injury to the lacrimal sac or central nervous system, we have performed 50 cadaver dissections and measured 7 anatomic landmarks that may aid the surgeon in preventing these complications. We have also included a review of the literature concerning the complications of endoscopic and intranasal sinus surgery addressed herein.