Sex determination in crayfish: are intersex Cherax quadricarinatus (Decapoda, Parastacidae) genetically females?

In the Australian red-claw crayfish Cherax quadricarinatus (von Martens) (Decapoda, Parastacidae), a gonochoristic species, seven different combinations of intersex individuals (with both male and female genital openings) have been described. However, to date, the genetic basis for this phenomenon has not been investigated. This study was designed to test a simple chromosome-based sex-determination model for C. quadricarinatus that assumes the male to be the homogametic (ZZ) sex. According to our model, intersex individuals that are functionally males are genetically females (WZ). Individual crosses were performed between intersex and female crayfish, with control crosses being performed between normal males and females. The control crosses yielded, in most cases, the expected 1:1 sex ratio in the F1 progeny. Crosses between intersex individuals and females yielded a 1:3 (male:female) sex ratio in most crosses. According to our hypothesis, one-third of the females produced in a cross of a female with an intersex animal should be WW females. The hypothesis was tested by crossing normal males with F1 females, which were progeny of intersex fathers. These crosses yielded almost 100% females, a finding that conforms to the above-suggested sex determination model for C. quadricarinatus and the female WZ genotype of intersex individuals.

A pilot study evaluating the treatment of postparotidectomy sialoceles with botulinum toxin type A.

OBJECTIVE: To report our experience in treating 4 cases of recurrent siacloceles with botulinum toxin type A after partoid surgery. DESIGN: This is a prospective, nonrandomized, nonblinded pilot study describing a new use for botulinum toxin type A. SETTING: Tertiary academic medical center. PATIENTS: Four patients (2 men and 2 women) with persistent postparotidectomy sialoceles who had undergone various treatment failures were included. The diagnosis was made by fine-needle aspiration of the mass based on well-recognized cytologic features of the entity, as well as an elevated amylase level and no evidence of tumor or infection. INTERVENTIONS: Sialoceles were aspirated before local injection of botulinum toxin type A (30-50 U) subcutaneously. MAIN OUTCOME MEASURES: The patients were followed up 1 week after receiving botulinum toxin type A injection and then at monthly intervals. They were extensively questioned and examined for any evidence of side effects or recurrence. RESULTS: All patients had total resolution of sialocele or external salivary fistula within 1 month of treatment. None of the patients to date have demonstrated recurrences at 7 through 13 months, and there were no complications, particularly facial nerve weakness. CONCLUSION: Our findings suggested that botulinum toxin type A offers a highly effective, safe, and noninvasive method of treatment in postparotidectomy sialocele.

Acute effects of antileukotrienes on sinonasal polyposis and sinusitis.

Recently, leukotrienes have been implicated in the mediation of bronchoconstriction and inflammatory changes in asthma. Leukotriene levels have also been shown to be elevated in patients with asthma as well as in those with sinonasal polyposis and sinusitis. The leukotriene synthesis inhibitor zileuton and the leukotriene receptor antagonist zafirlukast have been shown to produce subjective and objective improvements in patients with mild to moderate asthma. Given these findings, we evaluated the efficacy of these two medications in controlling sinonasal polyposis and their associated symptoms. We treated 40 patients diagnosed with sinonasal polyposis and sinusitis with either zileuton or zafirlukast. No other change was made in their standard therapy. Outcome measures included subjective interviews and questionnaire responses, as well as office endoscopic examinations and chart reviews. At study's end, 36 patients were available for evaluation. Twenty-six had taken zafirlukast, five had taken zileuton, and five others had switched from zafirlukast to zileuton. Overall, 26 patients (72%) experienced subjective improvement in their symptomatology after starting their medication. Statistically significant improvement was noted with respect to headache, facial pain and pressure, ear discomfort, dentalgia, purulent nasal discharge, postnasal drip, nasal congestion and obstruction, olfaction, and fever. An objective alleviation, or at least stabilization, of sinonasal polyposis was seen in 50% of the patients. Four patients (11%) discontinued their medication because of side effects. We conclude that antileukotrienes might play a significant role in controlling polyposis and symptoms secondary to sinonasal disease, and they might be a viable alternative to long-term oral steroid therapy and repeated surgical debridement.

Cutaneous-evoked tinnitus. II. Review Of neuroanatomical, physiological and functional imaging studies.

Cutaneous-evoked tinnitus is a clinical entity that has not been reported previously in the neurootological literature. Herein, a neuroscience framework that encompasses several distinct areas of research is used to conceptualize and help understand this phenomenon. We review normal neuroanatomical and physiological interactions between auditory and somatosensory systems in mammals. Also considered are mechanistic accounts of lesion-induced changes in the CNS following deafferentation/deefferentation of peripheral sensory or motor structures that may have a relationship to this phenomenon, as well as the role of functional imaging modalities in studying various phantom perceptions.

Cutaneous-evoked tinnitus. I. Phenomenology, psychophysics and functional imaging.

DC00166e and acute unilateral deafferentation of the auditory periphery (auditory and vestibular afferents) can induce changes in the central nervous system that may result in unique forms of tinnitus. These tinnitus perceptions can be controlled (turned on and off) or modulated (changed in pitch or loudness) by performing certain overt behaviors in other sensory/motor systems. Clinical reports from our laboratory and several other independent sources indicate that static change in eye gaze, from a neutral head-referenced position, is one such behavior that can evoke, modulate and/or suppress these phantom auditory events. This report deals with a new clinical entity and a form of tinnitus that can be evoked directly by cutaneous stimulation of the upper hand and fingertip regions. In 2 adults, cutaneous-evoked tinnitus was reported following neurosurgery for space-occupying lesions at the base of the skull and posterior craniofossa, where hearing and vestibular functions were lost completely and acutely in one ear (unilateral deafferentation) and facial nerve paralysis (unilateral deefferentation) was present either immediately following neurosurgery or had occurred as a delayed-onset event. Herein, we focus on the phenomenology of this discovery, provide perceptual correlates using contemporary psychophysical methods and document in one individual cutaneous-evoked tinnitus-related neural activity using functional magnetic resonance imaging. In a companion paper, neuroanatomical and physiological interactions between auditory and somatosensory systems, possible mechanistic accounts and relevant functional neuroimaging studies are reviewed.

Clinical applications of otoacoustic emissions in sudden hearing loss.

Sudden hearing loss (SHL) is a controversial topic for which no definitive practical guidelines exist. Studies employing vasodilators, plasma expanders, anticoagulants, and carbogen inhalations have shown no improvement over the rate of spontaneous recovery. At present, there is insufficient evidence to support medical treatment for SHL, except steroid therapy in selected patients. Distortion product otoacoustic emissions (DPOAEs) are sensitive to cochlear disorders and are absent in ischemic injury to the cochlea, but can persist in cochlear neuritis. In a prospective study of 10 patients who presented to Albany Medical Center from 1995 to 1996, three patients with intact DPOAEs at presentation had an average improvement of 33 dB in the pure-tone average (PTA) of 0.5, 1.0, and 2.0 kHz with steroid therapy, whereas five of seven patients with absent DPOAEs had no improvement in hearing despite steroid therapy in six patients. The presence of DPOAEs may be a useful prognostic factor that positively correlates with recovery from SHL.

Morbidity of combined therapy for the treatment of supraglottic carcinoma: supraglottic laryngectomy and radiotherapy.

Many surgeons find that patients have increased morbidity after supraglottic laryngectomy if postoperative irradiation is given, but this remains poorly documented. Twenty-nine patients undergoing supraglottic laryngectomy were retrospectively reviewed. Seventeen received postoperative radiotherapy, and 12 did not. The mean follow-up was 64 months. When compared to patients treated with supraglottic laryngectomy alone, irradiated patients had a significantly higher incidence of lifelong gastrostomy dependency (35% versus 0%; p = .03) and acute upper airway obstruction (29% versus 0%; p = .05). There was a trend toward greater tracheotomy dependency (24% versus 0%), aspiration pneumonia (35% versus 9%), and delayed independent swallowing (34.8 weeks versus 7.8 weeks) in the patients treated with combined therapy, but this difference was not significant. A morbidity index score was developed to evaluate the overall lifelong morbidity of these patients, and this was found to be significantly higher in patients treated with surgery and radiotherapy (2.29 versus 0.83; p = .04). Overall survival was equal in both groups. We have shown that radiotherapy increases the morbidity of supraglottic laryngectomy. This should be considered when planning treatment for patients with supraglottic carcinoma.

Current concepts in the clinical management of patients with tinnitus.

The current management in tinnitus of sensorineural origin is reviewed. Epidemiological data demonstrates that 90% of patients with hearing loss experience some tinnitus. Approximately 1% of the population suffer from a chronic tinnitus that causes severe distress and requires some type of management intervention. Present non-surgical therapies include masking techniques, psychological counseling, and biofeedback. There are also a number of drugs that have been applied, the most common being antidepressants. These have had the most success in managing patients with tinnitus, although it is currently felt that antidepressants treat underlying psychological problems rather than directly affect the tinnitus. The other large class of drugs include benzodiazopans, in addition to a new synthetic analog of a natural prostaglandin E1, misoprostol. Despite the many drugs now available, none has been approved by the United States Food and Drug Administration for the treatment of tinnitus. Many surgical therapies have been advocated but are directed towards the treatment of concurrent vertigo or for tumors of the cerebellopontine angle, with tinnitus sometimes being relieved by the operation. Specific surgical procedures such as cochlear resection and microvascular decompressions lack clear-cut efficacy. Despite author bias and a myriad of treatment modalities at present, there is still no specific therapy that definitively relieves tinnitus clinically.

Advances in the development of the interferometric otoscope.

Present measurement techniques for middle ear function have inherent limitations because they are either spatially insensitive (acoustic immittance) or descriptive and qualitative in nature (otoscopy). By integrating advances in electrooptic technology (fiber optics, miniature diode lasers, solid-state detector arrays) and digital processing, further advances are possible. On the basis of measurements taken with electronic speckle-pattern interferometry on human temporal bones and models, we demonstrate quantitative static and dynamic vibration/displacement characteristics of the tympanic membrane with high spatial resolution. Our presentation emphasizes advantages of optically based methods and demonstrates computerized signal processing capable of fringe localization, enhancement, and counting. Miniaturization and real-time digital image processing in the clinical setting is the goal of this research.

Current concepts in the diagnosis and treatment of sudden sensorineural hearing loss.

Sudden hearing loss (SHL) has been a controversial topic in the literature for the past several decades. Although much theoretical work has been done regarding its diagnosis and treatment, no useful practical guidelines exist for application to current patient management. Many authors have discussed the various treatment protocols available to treat this entity, but only a handful of dated, clinical studies supporting these treatments are available. More recent studies applying treatment protocols including vasodilators, plasma expanders, anti-coagulants, and carbogen inhalations have shown no improvement over the rate of spontaneous recovery without therapy. Except in cases of therapy directed toward known predisposing factors, there is insufficient evidence in the literature to support medical treatment for SHL, although steroid therapy appears to be useful in selected patients. Our own review of 14 patients with SHL is presented. A standard diagnostic and therapeutic approach based on a comprehensive review of the literature is described that can be applied to most patients presenting with SHL.

P-glycoprotein expression in the squamous cell carcinoma of the tongue base.

P-glycoprotein (PGP), which is a product of the multidrug resistance gene (MDR1), is an active transmembrane efflux pump responsible for detoxifying normal cells as well as rendering tumor cells resistant to chemotherapy. It has also been implicated to be expressed by more aggressive cancers. It has not been well described in squamous cell carcinoma of the head and neck. In this investigation, an attempt was made to characterize advanced squamous cell carcinoma of the base of tongue with respect to expression of PGP. Using immunohistochemical techniques two anti-PGP monoclonal antibodies (JSB1 and C494) were used to detect PGP in these lesions, and an attempt was made to correlate levels of PGP staining and various tumor parameters. Usefulness of PGP in predicting survival and time to recurrence was also examined for these advanced lesions. All 33 base of tongue lesions showed staining for PGP with these monoclonal antibodies. This was the first study examining utility of C494 in detecting PGP in squamous cell carcinoma at this site. Increased level of PGP expression was seen in better-differentiated tumors as well as in tumors with diploid DNA. A trend of higher PGP expression and decreased survival emerged. This may represent a true relationship, but inherent heterogeneity of PGP expression within cells cannot be excluded. Both antibodies examined appear to be useful in the investigations of PGP distribution in squamous cell carcinomas of the head and neck sites by immunohistochemical techniques. Prognostic value of the level of PGP expression remains to be seen.

Electronic speckle pattern interferometry of the vibrating larynx.

Laser holography is a technique that creates a three-dimensional image of a static object. This technique can be applied to the analysis of vibrating structures. Electronic speckle pattern interferometry uses a laser for illumination of the vibrating object and solid state detectors and digital hardware technology for capturing and processing the image in real time. This was performed on a human cadaver larynx and is the first time an interferogram of vibrating vocal cords has ever been obtained. Dark and bright interference fringes are seen that represent the vibratory motion of the vocal folds. These are presented in still photos as well as real-time on videotape. This method can provide advantages over current techniques of laryngeal study: it is sensitive to motion in the vertical dimension, and the digital data can be quantitatively analyzed. Application of this technique to study the larynx should eventually be a valuable clinical tool and provide quantitative research data.

Anomalous cross-modal plasticity following posterior fossa surgery: some speculations on gaze-evoked tinnitus.

A unique and intriguing form of subjective tinnitus evoked by eye gaze is reviewed. A new perspective is presented because this condition is sufficiently different from other forms of subjective tinnitus and its manifestation cannot be adequately explained by existing models or conceptual frameworks. Our examination of this topic considers pathophysiologic changes in the central nervous system in the context of deafferentation-induced plasticity. Potential neuroanatomical areas contributing to this effect include a number of distributed and functionally diverse areas in the brainstem and neocortex involved in the auditory control of eye movements. We also consider contemporary psychophysical methods to evaluate the perceptual correlates of this phenomenon and tools for the development of objective tinnitus measurements. Although theoretical and speculative in nature, this article is intended to stimulate interest in, advance knowledge of, and provide a better understanding about this condition.

An unexpected fetal outcome following a severe maternal motor vehicle accident.

BACKGROUND: Maternal motor vehicle injury occurs commonly and can cause serious fetal injury. Optimum pregnancy management at the time of maternal presentation following trauma requires reliable methods of fetal assessment. In this report, we present a case in which currently accepted methods of fetal assessment initially failed to demonstrate catastrophic fetal brain injury following a maternal motor vehicle accident. CASE: A 28-year-old primigravida woman at 27 weeks' gestation was in a pedestrian motor vehicle accident, suffering a closed head injury and multiple fractures. Initial fetal assessment included cardiotocographic monitoring for 24 hours fetal ultrasound, both of which were normal, as was a biophysical profile done on the fifth day after the accident. These were repeated at intervals, but definite evidence of fetal brain injury was not seen until unilateral ventricular dilatation was documented on ultrasound at 35 weeks' gestation. Postnatal imaging showed microcephaly, hydrocephalus ex vacuo, and multiple hemispheric hypodensities, likely representing post-traumatic hemorrhages with secondary infarction. At the age of 4 years, the child is cortically blind, epileptic, and quadriparetic. CONCLUSION: This pregnancy outcome was unexpectedly poor despite the reassuring initial assessment. We caution that these methods may not provide accurate early fetal assessment, especially when fetal brain stem function is spared.

Auditory perceptual and visual-spatial characteristics of gaze-evoked tinnitus.

Auditory perceptual and visual-spatial characteristics of subjective tinnitus evoked by eye gaze were studied in two adult human subjects. This uncommon form of tinnitus occurred approximately 4-6 weeks following neurosurgery for gross total excision of space-occupying lesions of the cerebellopontine angle and hearing was lost in the operated ear. In both cases, the gaze-evoked tinnitus was characterized as being tonal in nature, with pitch and loudness percepts remaining constant as long as the same horizontal or vertical eye directions were maintained. Tinnitus was absent when the eyes were in a neutral head-referenced position with subjects looking straight ahead. The results and implications of ophthalmological, standard and modified visual-field assessment, pure-tone audiometric assessment, spontaneous otoacoustic emission testing and detailed psychophysical assessment of pitch and loudness are discussed.

Transsphenoidal hypophysectomy through the external rhinoplasty approach.

The external rhinoplasty approach is a refinement of the well-recognized sublabial transseptal technique for transsphenoidal hypophysectomy first introduced by Cushing in 1910. This article relates our experience with 111 cases of transsphenoidal hypophysectomy performed during a 10-year period (1982-1992) and includes a detailed description of our use of the external technique. Fifty-one patients were male, and 60 were female. Ages ranged from 12 years to 80 years, with an average of 46 years. One hundred one patients had pituitary adenomas, four had craniopharyngiomas, two had inverting papillomas, and there was one each of lymphoma, metastatic prostate cancer, pituitary abscess, and posttraumatic cerebrospinal fluid leak. Nine of the operations were for recurrent adenomas. Complications included 8 symptomatic anterior septal perforations and 13 asymptomatic posterior perforations. Five had transient cerebrospinal fluid rhinorrhea, five had perioperative hemorrhages, two had minor postoperative columellar deformities, and one had injury to the internal carotid artery requiring embolization. We have found the external technique for transsphenoidal hypophysectomy to be a reliable and facile means for nasal exposure of the sphenoid sinus and pituitary gland without loss of nasal tip projection or significant cosmetic deformity.

The disconnected ear: phenomenological effects of a large acoustic tumor.

OBJECTIVE: To document the existence of a peripheral auditory disconnection syndrome in a 23-yr-old male with a large tumor of the right cerebellopontine angle using contemporary behavioral, electroacoustic, and electrophysiologic auditory tests. DESIGN: Single subject with repeated measures. RESULTS: In spite of a profound hearing loss in an ear with a large cerebellopontine angle tumor determined by behavioral audiometry, distortion product otoacoustic emissions, surface recorded brain stem auditory evoked potentials, and transtympanic electrocochleography (click evoked compound action potentials and tone evoked cochlear microphonics) demonstrated that the cochlea was intact and functional over a broad bandwidth and intensity range. CONCLUSIONS: A peripheral auditory disconnection syndrome is demonstrated in a 23-yr-old male with a large tumor of the cerebellopontine angle. In this instance, the tumor effectively deafferentated the peripheral from central auditory nervous system, resulting in profound hearing loss of presumed neural origin. It is suggested that other pathologic conditions/mechanisms could produce similar findings.

Mechanical and metabolic performance of the rat heart: effects of combined stress of heat acclimation and swimming training.

Although the individual effects of heat acclimation and swimming exercise on cardiovascular reserve and efficiency have been studied, the relative and cumulative effects of these interventions have not. Myocardial developed force, coronary flow (CF), and oxygen consumption during baseline conditions and during pacing-induced tachycardia were therefore studied in isolated perfused hearts from four groups of rats: normothermic sedentary (C), heat acclimated sedentary (AC), normothermic swimmers (CS), and heat acclimated swimmers (ACS). Normothermic temperature was 24 degrees C. Heat acclimation was attained by continuous exposure to 34 degrees C for one and two months. Swimmers had two daily 75 minute sessions for five days a week with water temperatures of 33-35 degrees C and 36-38 degrees C for CS and ACS rats, respectively. After one month AC animals showed a remarkable decrease in O2 consumption. In contrast, ACS increased both O2 consumption and the maximal isometric force generated. After two months, O2 consumption of AC rats continued to be low. The heart failed to restitute the force developed at high pacing frequency. In these rats CF was remarkably low and remained unchanged with increased pacing. In contrast ACS maintained the ability to develop force at all pacing rates at a level similar to that of the normothermic C and ACS rat hearts, but at high oxygen cost. The data suggest that the AC heart is more efficient but cannot meet demands at high pacing rates. In contrast, swimming in the heat improved performance of ACS temporarily, without decreasing the metabolic rate.

Evaluation of cefixime in the treatment of bacterial maxillary sinusitis.

The efficacy and safety of cefixime, the first oral third-generation cephalosporin, were evaluated in a multicenter clinical trial involving 118 adult patients with acute sinusitis or acute exacerbations of chronic sinusitis. Patients received a single daily dose of 400 mg of cefixime for a mean duration of 10 days; 106 patients completed a course of therapy. Clinical cure and improvement were achieved in 90% of these patients (61% cured and 29% improved). Among the patients evaluated again 2 weeks after therapy, 91% had a sustained clinical cure or improvement. Sinus exudate specimens were obtained from all patients by transantral puncture before therapy. Pathogens were isolated from 76 patients (66%), the most common pathogens being Haemophilus influenzae, alpha-hemolytic streptococci, and Streptococcus pneumoniae. Eighty-six percent of pathogens were presumed eradicated. Three patients discontinued therapy because of side effects. The most frequently reported adverse effects were gastrointestinal, with 20% of patients reporting diarrhea. Cefixime was effective in the treatment of bacterial sinus infections in adults and was well tolerated.