Deinococcus as new chassis for industrial biotechnology: biology, physiology and tools.

Deinococcus spp are among the most radiation-resistant micro-organisms that have been discovered. They show remarkable resistance to a range of damage caused by ionizing radiation, desiccation, UV radiation and oxidizing agents. Traditionally, Escherichia coli and Saccharomyces cerevisiae have been the two platforms of choice for engineering micro-organisms for biotechnological applications, because they are well understood and easy to work with. However, in recent years, researchers have begun using Deinococcus spp in biotechnologies and bioremediation due to their specific ability to grow and express novel engineered functions. More recently, the sequencing of several Deinococcus spp and comparative genomic analysis have provided new insight into the potential of this genus. Features such as the accumulation of genes encoding cell cleaning systems that eliminate organic and inorganic cell toxic components are widespread among Deinococcus spp. Other features such as the ability to degrade and metabolize sugars and polymeric sugars make Deinococcus spp. an attractive alternative for use in industrial biotechnology.

Extracranial lower cranial nerve sheath tumors.

OBJECTIVE: The purpose of this article is to review the clinicoradiographic features of lower cranial nerve sheath tumors and to outline surgical approaches that allow the safe and complete resection of these lesions. METHODS: Thirteen patients with lower cranial nerve sheath tumors of the infratemporal fossa were surgically treated between 7/88 and 10/99. A retrospective chart analysis provided details pertaining to clinical manifestations, radiographic assessment, intraoperative findings, tumor histology, and postoperative results. RESULTS: The most common presenting symptoms were neck pressure and voice change while submucosal palatal fullness and vocal cord paralysis were the most common presenting signs. All tumors were removed via lateral skull base approaches and the most common postoperative sequelae was dysphasia. CONCLUSION: Lower cranial nerve sheath tumors of the infratemporal fossa usually reach considerable size before diagnosis because of a naturally slow growth rate in this relatively silent location. The safe surgical removal of these tumors, based on superior control of the internal carotid artery, can be achieved through the use of contemporary lateral skull base techniques.

Duration of neuronal stretch correlates with functional loss.

Postoperative cranial nerve weakness or paralysis is not uncommon in many otolaryngologic surgical procedures. Our study used a rat model to test the hypothesis that the length of time that a nerve is under tension may be an important variable in the amount of postoperative paresis. Forty Sprague-Dawley rats were divided into 4 groups that underwent either a sham operation or a traction injury for 1, 2, or 5 minutes. The traction injury was performed with a vessel loop placed around the sciatic nerve with 50 g of tension. Traction injury for 1 or 2 minutes did not result in any statistical differences in the motor capabilities of the lower limb. However, those animals with a stretch injury for 5 minutes had a significant loss of function (P < 0.01) when compared with all other groups. Histologic examination of nerves harvested on postoperative day 7 showed no evidence of mechanical injury. This study demonstrates that even minimal tension, if maintained for a significant amount of time, may result in postoperative weakness.

Cerebrospinal fluid fistula after transtemporal skull base surgery.

OBJECTIVES: The purpose of this article is to outline our methods for the prevention and management of cerebrospinal fluid (CSF) leak after transtemporal skull base surgery. METHODS: A total of 589 patients underwent a variety of transtemporal surgical approaches for the extirpation of skull base tumors at our institution from July 1988 to October 1999. The medical records were retrospectively reviewed to identify the tumor histology, size, and location as well as the surgical approach, defect reconstruction technique, and the incidence of postoperative CSF leak. RESULTS: The risk of CSF fistulae was greatest in utilizing the restrosigmoid approach (8%) and least in those who underwent a translabyrinthine approach (4%). Tumor size had no bearing on the incidence of the CSF leak and the overall incidence of meningitis was 1.0%. CONCLUSION: The proper surgical technique will minimize the risk of CSF leak after transtemporal skull base surgery. Immediate management of CSF fistulae helped prevent meningitis in the majority of these patients.

Incidental petrous apex findings on magnetic resonance imaging.

We performed a retrospective chart review to categorize a group of petrous apex findings that were noted incidentally on magnetic resonance imaging (MRI) in 88 patients. These patients were among those who had been seen at a tertiary care center between July 1988 and July 1998. These incidental findings, which were unrelated to the presenting clinical manifestations, included asymmetric fatty bone marrow (n = 41), inflammation (19), cholesterol granulomas (14), cholesteatomas (9), and neoplasms (5). Followup imaging and clinical surveillance of these patients has not demonstrated any significant change in the incidentally detected lesions. In all cases, the incidental MRI findings represented benign pathology.

Endovascular treatment of transverse-sigmoid sinus dural arteriovenous malformations presenting as pulsatile tinnitus.

Transverse-sigmoid sinus dural arteriovenous malformations (DAVM) are uncommon vascular lesions for which complete cure may be difficult to obtain. A wide variety of treatments for these lesions include observation, arterial compression, surgical resection, and endovascular embolization. We propose that transverse-sigmoid sinus DAVM can be completely cured by occluding the ipsilateral dural sinus with detachable balloon and Guglielmi detachable coils (GDC) coils before arterial feeder embolization with histoacryl. Three patients who presented with pulsatile tinnitus and normal magnetic resonance imaging (MRI) studies underwent angiography, which demonstrated transverse-sigmoid sinus DAVM. All three patients wer treated with retrograde transvenous sinus embolization with complete occlusion of the transverse-sigmoid sinus with detachable balloons and GDC coils with preservation of the vein of Labbé. Subsequently, the various feeders from the external carotid artery were embolized. The tentorial arteries arising from the ipsilateral internal carotid arteries were not embolized in any of the cases, which were still contributing to the DAVM. Complete cure with thrombosis of the tentorial branch of the internal carotid artery (ICA) was seen on follow-up angiogram 1 day after embolization in one patient and on 4-week and 6-week follow-up angiograms in the other two patients. Complete occlusion of the transverse sinus proximal to the vein of Labbé, in spite of incomplete arterial feeder embolization, can result in complete cure of the transversesinus dural AVF if adequate time is given for the remaining feeders to occlude, once the fistula is obliterated.

Prevention and management of cerebrospinal fluid fistula after transtemporal skull base surgery.

The incidence of cerebrospinal fluid (CSF) fistula after transtemporal skull base surgery can range from 4% to 19%. The risk of CSF leak may be related to tumor size and location, the extent of the dural defect, and the technical aspects of the wound reconstruction. Prevention of meningitis depends on the early detection and management of CSF leakage. Five hundred eighty-nine patients underwent a variety of transtemporal surgical approaches for the extirpation of skull base tumors at our institution from July 1988 to October 1999. The medical records were reviewed retrospectively to identify the tumor histology, size, and location, as well as the surgical approach, defect reconstruction technique, and the incidence of postoperative CSF leak. The risk of CSF fistulae was greatest in using the retrosigmoid approach (8%) and lowest in those who underwent a translabyrinthine approach (4%). Tumor size had no bearing on the incidence of the CSF leak and the overall incidence of meningitis was 1.0%. This article outlines our institutional objective for the prevention and management of CSF fistula after transtemporal skull base surgery. Illustrative cases will be presented.

The effects of clonidine premedication and scalp infiltration of lidocaine on hemodynamic responses to laryngoscopy and skull pin head-holder insertion during skull base procedures.

This study was designed to determine if oral clonidine or lidocaine, injected into the scalp before head-holder (H-H) insertion, would attenuate the hemodynamic effects associated with intubation and H-H placement. Thirty-four patients undergoing skull base procedures were randomized to four groups. Group 1 received clonidine 5 mcg/kg po before surgery with 10 to 15 ml of 1% lidocaine infiltrated at pin insertion sites; Group 2 received clonidine with saline infiltration; Group 3 received a placebo preoperatively and had lidocaine infiltrated at pin sites; and Group 4 received a placebo with saline infiltrated. All patients had a standard anesthetic titrated to a 10 to 14 Hz EEG endpoint during laryngoscopy and H-H placement. Mean arterial pressure (MAP) was similar between groups during intubation, but heart rate (HR) increased in patients who did not receive clonidine. H-H application increased HR and MAP in Group 4. HR also increased after H-H placement in patients who received oral clonidine, while patients receiving scalp lidocaine or both clonidine and scalp lidocaine had little change in either value. Clonidine attenuated HR increases after laryngoscopy but not after H-H placement. Lidocaine injected at the pin sites reduced HR, and MAP increased after H-H insertion. The combination of oral clonidine and scalp lidocaine blunted hemodynamic responses to both intubation and H-H placement.

Carotid-cavernous fistulas: pathogenesis and routes of approach to endovascular treatment.

The etiology, classification, clinical presentation, complications, and intravascular routes to image and treat carotid-cavernous fistulas percutaneously are described. Endoarterial and transvenous approaches (through the jugular, inferior petrosal, or cavernous veins) are discussed in relation to the etiology, size, and characteristics of the fistulas, as well as in relation to the planned therapeutic approach and its possible complications. Possible outcomes, with particular attention to the internal carotid circulation, side effects, and complications also are discussed in relation to etiology and type of fistula. Four exemplary cases are presented.

Clinical course of pediatric congenital inner ear malformations.

OBJECTIVE: To determine any factors that could improve the early detection and management of congenital inner ear malformations. STUDY DESIGN: A retrospective review was performed of all patients with a diagnosis of inner ear malformation at Loyola University Medical Center (LUMC) and the Hospital for Sick Children (HSC) between 1987 and 1995. Clinical records and audiometric data were accumulated. One neuroradiologist reviewed every temporal bone computed tomography (CT) scan. METHODS: Forty-six pediatric patients with congenital inner ear anomalies evaluated at two tertiary care hospitals. RESULTS: The average patient age at initial assessment was 25.7 months. A family history of hearing loss was noted in only five patients (12.8%). A major nonotological deformity was seen in 41% of patients. The average hearing threshold was 88 dB. All three patients with sudden hearing loss had vestibular aqueduct enlargement. Two of the three patients with common cavity anomalies had a history of recurrent meningitis. Twenty-seven patients had a vestibular aqueduct deformity, the most frequent radiographic abnormality in the series. CONCLUSIONS: Because inner ear malformation was diagnosed after 24 months of age in a significant percentage of patients, we recommend increased parental education and vigilance by primary care practitioners. Universal newborn screening may be the key to earlier detection of these infants. For children with idiopathic sensorineural hearing loss, we recommend a temporal bone CT scan. Patients with vestibular aqueduct enlargement must be counseled about the risk of progressive sensorineural hearing loss, meningitis, and the need to avoid contact sports. Patients with common cavity abnormalities should be considered for exploratory tympanotomy and also educated about the risk for meningitis.

[Synthesis and properties of photolabile caged phosphotriester derivatives of dinucleoside phosphates]. / Sintez i svoistva blokirovannykh fotolabil'nymi gruppami fototriéfirnykh proizvodnykh dinukleozidfosfatov.

Dinucleoside phosphates that harbor phosphate groups transiently blocked (caged) by o-nitrobenzyl or o-nitroveratryl residues were synthesized. It was shown that the conditions of the UV-induced deprotection largely depend on the nature of the protective group. The phosphotriesters obtained were resistant toward snake venom phosphodiesterase and nucleases of the cellular extract. The synthesis of the dinucleoside phosphates containing a photolabile group preceded the incorporation of the modified blocks into extended oligonucleotides by the phosphoramidite method.

Neuroprotection due to irrigation during bipolar cautery.

OBJECTIVE: To test whether irrigation during bipolar cautery confers thermoprotection from neuronal injury. DESIGN: A rat animal model (15 rats for each treatment group) was used to test the thermoprotective effects of irrigation during bipolar cautery. In this model, the sciatic nerve was exposed, and a 1-second stimulus was applied using bipolar cautery forceps at 40 or 20 W placed directly on the nerve in the presence or absence of simultaneous irrigation. The effects of cautery were determined on the basis of clinical gait analysis by means of the Sciatic Functional Index, temperature response, and neuropathological findings. RESULTS: The degree of paresis was reduced with irrigation. Neuropathological examination of the sciatic nerve after cautery showed significant axonal loss (more small than large fibers) with concomitant demyelination, which was partially inhibited by irrigation (chi2; P = .04). The mechanism of thermoprotection by irrigation was not the result of a reduction in the temperature spike that followed cautery, but resulted from a reduced temperature response during the 15 seconds that followed 40- or 20-W stimulation with bipolar cautery. CONCLUSIONS: Simultaneous irrigation and bipolar cautery enhance temperature recovery to basal levels and protect the peripheral nerve from the effects of cautery.

Remifentanil-based anesthesia versus a propofol technique for otologic surgical procedures.

Otologic procedures require a still surgical field and are associated with a 50% incidence of emetic symptoms. Propofol reduces nausea and vomiting but not intraoperative movement. This study compares a remifentanil/propofol anesthetic to a propofol/fentanyl combination to determine which provides the best perioperative conditions for otologic microsurgery. Eighty healthy patients were randomly assigned to receive one of the anesthetic combinations. Demographic data, hemodynamic variables, movement, and bispectral index monitoring values in addition to anesthetic emergence, nausea, vomiting, pain, and other recovery variables were compared between groups with appropriate statistical methods. Both groups were similar. Times to eye opening (7.7 +/- 0.7 vs 12.4 +/- 1.2 minutes) and extubation (9.8 +/- 0.9 vs 12.4 +/- 1.0 minutes) were shorter with remifentanil. This group also had lower hemodynamic variables and movement (23% vs 65%) under anesthesia. Postoperative pain was mild in both groups, but remifentanil patients had more than the propofol group. All other postoperative parameters were similar. Remifentanil-based anesthesia produces better hemodynamic stability, less movement, and faster emergence after otologic surgery, with propofol's antiemetic effect, for the same cost.

Osteotome sinus elevation and implant placement with narrow size bioactive glass.

A procedure using osteotomes and bioactive glass as an alloplastic bone graft material is discussed, and three clinical cases are reviewed. Bioactive glass of a narrow size range (300-355 microns) has been shown to be osteoconductive and allows for good integration and regeneration of surrounding bony tissue. We have found this technique to be a predictable method of preparing and placing longer implants in the region of the maxillary premolar region without the need for additional donor site morbidity.

The importance of magnetic resonance imaging in the evaluation of vertigo and imbalance.

Vertigo and imbalance are believed to be rare manifestations of skull base neoplasms. Patients with skull base neoplasms can present with vague otolaryngological complaints, including diplopia, facial numbness, facial weakness, hearing loss, tinnitus, hoarseness, headache, and otalgia. Physical examination of these patients can sometimes reveal paralysis or paresis of cranial nerves. Magnetic resonance imaging (MRI) is the gold standard for evaluation of cranial nerve involvement in skull base diseases. Vertigo and imbalance can be manifestations of a neuropathy or lesion within the vestibular system and may be subtle or overlooked findings in patients with skull base diseases. The purpose of this article is to review the clinical manifestations of patients presenting with vertigo and imbalance who were found to have skull base neoplasms. We will also highlight the importance of MRI in diagnosis and management of these patients.

Comparison of 3 different anesthetic techniques on 24-hour recovery after otologic surgical procedures.

Intravenous propofol anesthesia is better than inhalational anesthesia for otologic surgery, but cost and intraoperative movement make this technique prohibitive. This study compares a propofol sandwich anesthetic with a total propofol or inhalational anesthetic for otologic surgery to determine which produces the best perioperative conditions and least expense. One hundred twenty patients undergoing ear surgery were randomly chosen to receive an anesthetic with either isoflurane (INHAL), total propofol (TPROP), or propofol used in conjunction with isoflurane (PSAND). Postoperative wakeup and the incidence and severity of nausea, vomiting, and pain were compared among groups. Antiemetic administration and discharge times from recovery and the hospital were also compared. The groups were similar, but anesthesia times were longer in the INHAL group. Emergence from anesthesia after PSAND or TPROP was more rapid than after INHAL. Recovery during the next 24 hours was associated with less nausea and vomiting with PSAND than with INHAL. The cost of the PSAND anesthetic was similar to that of INHAL, and both were less than TPROP. PSAND anesthesia may be similar to TPROP and better than INHAL for otologic procedures. PSAND was less expensive than TPROP and produced a similar recovery profile and antiemetic effect in the 24-hour period after surgery.

Treatment of malignant neoplasms of the lateral cranial base with the combined frontotemporal-anterolateral approach: five-year follow-up.

Technical advances in accessing the lateral cranial base have permitted disease in this area previously deemed inoperable to be resected. The procedures required to effect an oncologically adequate resection are often long and accompanied by the potential for serious, even life-threatening, complications. Although it has been demonstrated that such disease can be extirpated, the question of whether such heroic surgery improves long-term survival remains unanswered. We retrospectively reviewed the records of 25 patients who underwent a combination of frontotemporal craniotomy with other, more conventional, anterolateral procedures (eg, infratemporal fossa approach, maxillectomy, orbitectomy, mandibulopharyngectomy) to resect stage IV malignant disease of the lateral to midcranial base between 1983 and 1990. Perioperative deaths occurred in 2 patients, 1 patient died of unrelated causes free of disease, and 2 patients were lost to follow-up, leaving 20 patients with a minimum 5-year evaluation. Five (25%) of the 20 patients we monitored were free of disease. Of those patients in whom recurrent disease developed, local control was achieved in about 50%; however in 80% of those with recurrence, metastatic disease developed. Surgical treatment of selected stage IV malignant disease of the lateral to midcranial base appears to have provided long-term disease-free survival to 25% of patients in this series who would otherwise have had little hope of survival.

Thermoprotective mechanisms of irrigation during bipolar cautery.

Bipolar cautery is routinely used in operations of the head and neck, as well as in other specialties, both for dissection and for achieving hemostasis. Whereas simultaneous irrigation is frequently used to minimize neuronal injury, its effectiveness has not been tested under controlled conditions. Our objectives in this study were to test the hypothesis that including irrigation during bipolar cautery is thermoprotective and to identify the mechanisms underlying the thermoprotective effect. The thermoprotective role of irrigation with bipolar cautery was tested in a rat model in which the sciatic nerve was exposed and a 1-second stimulus at 40 or 20 watts was applied with bipolar cautery forceps placed directly on the nerve in the presence or absence of simultaneous irrigation. We used the Sciatic Functional Index as used to quantitate the degree of paresis induced. The results showed that simultaneous irrigation reduced the percentage of animals showing paresis. This effect was significant for animals exposed to 40- and 20-watt cautery. The mechanism for the reduction in the degree of paresis by irrigation could not be attributed to a lowering of the maximal temperature achieved after bipolar cautery. Instead, the thermoprotective mechanism of the irrigation involved an enhanced recovery to basal temperatures when measured at 15 seconds after nerve stimulation with 40 or 20 watts. Reducing the power from 40 watts to 20 watts did not significantly lessen the tissue temperature. The results of this study suggest that irrigation done simultaneously with bipolar cautery enhances temperature recovery to basal levels and plays a role in thermoprotection against the effects of cautery.

Otalgia. An isolated symptom of malignant infratemporal tumors.

OBJECTIVE: This study aimed to review a series of 18 patients with malignant infratemporal fossa tumors who presented with otalgia as the primary symptom. STUDY DESIGN: This was a retrospective case analysis. SETTING: All patients were evaluated and treated at a tertiary care academic medical institution. PATIENTS: Eighteen patients evaluated for otalgia in a normal-appearing ear, between July 1988 and July 1996, who were found to have a malignant infratemporal fossa tumor participated. INTERVENTIONS: Diagnostic testing included radiographic evaluations and tissue sampling through fine-needle aspiration cytology. Treatment methods were histology dependent. MAIN OUTCOME MEASURES: The time between the onset of otalgia and the tumor diagnosis was recorded. Overall treatment outcomes were reviewed. RESULTS: The period between the onset of otalgia and tumor diagnosis ranged from 4-21 months with a mean of 7.5 months. Adenoid cystic carcinoma was the most commonly seen tumor in this series of patients. CONCLUSIONS: The infratemporal fossa is a relatively protected region that may be the site of malignant neoplasms causing the isolated symptom of otalgia.

Cochlear neuromas.

OBJECTIVE: This study aimed to review the clinicoradiographic findings in 16 patients with unilateral cochlear neuromas. STUDY DESIGN: The data included in this presentation were obtained from a retrospective case review. SETTING: The study was conducted at a tertiary care academic institution. PATIENTS: Patients of any age, gender, or race with a unilateral cochlear neuroma participated. INTERVENTIONS: Standard audiometric and radiographic assessment was performed. MAIN OUTCOME MEASURES: Progressive sensorineural hearing loss was measured. RESULTS: Sensorineural hearing loss is out of proportion to the size of the tumor (< 8 mm in all 16 patients). CONCLUSIONS: Gadolinium-enhanced magnetic resonance imaging in the axial and coronal planes can help identify cochlear neuromas in selected patients with unilateral sensorineural hearing loss.