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.

Antiviral activity of conjugates between poly(L-lysine) and synthetic oligodeoxyribonucleotides.

Short (14 to 20-mer range) synthetic oligodeoxyribonucleotides (oligos) allow to modulate specifically viral or cellular gene expression at various stages thus providing a versatile tool for fundamental studies and a rational approach to antiviral chemotherapy. Several problems, such as metabolic stability and efficient cell internalization of oligos, still limit this approach appreciably, as briefly discussed here. We demonstrate here that the conjugation of 15-mer (beta)-anomeric oligos to poly(L-lysine) allows a specific protection of various cell lines against vesicular stomatitis virus infection at concentrations lower than 1 microM. This can be achieved with oligos complementary to the viral N-protein mRNA initiation site or to viral intergenic sequences, i.e., to untranscribed regions. No antiviral activity can be obtained with (alpha)-anomeric oligos directed against the same targets, although such analogues are much more resistant to nuclease degradation and form stable hybrids, at least in cell-free experiments.

Interferons and oncogenes in the control of cell growth and differentiation: working hypothesis and experimental facts.

This short review summarizes available evidence for (i) growth regulatory properties of exogenous as well as recently described autocrine IFNs, (ii) down-regulation of cellular oncogene expression with emphasis on c-myc and (iii) the possible involvement of the IFN-regulated 2-5A pathway at these levels. Initially described as a part of the IFN-induced antiviral mechanism, this double-stranded RNA-activated pathway leads to the preferential degradation of viral mRNAs in IFN-treated virus-infected cells probably through localized activation at the site of virus replication. Such mechanisms could be involved in the regulation of the stability of rapidly turning over mRNAs as for instance c-myc mRNA in IFN-treated cells. Whatever the elegance of the concept, however, experimental evidence is essentially circumstantial; tools developed in our group to strengthen the demonstration are briefly described.

Umbilical herniorrhaphy in cirrhotic patients.

During a ten-year period, 92 patients underwent an umbilical herniorrhaphy. Patients were divided into three groups: group 1, cirrhotic patients with ascites with functioning peritoneovenous shunts (n = 15); group 2, cirrhotic patients with ascites with nonfunctioning or no peritoneovenous shunts (n = 24); and group 3, noncirrhotic patients (n = 53). The charts were analyzed for postoperative mortality and morbidity and recurrence of the umbilical hernia. Umbilical hernia in cirrhotic patients with uncontrolled ascites was associated with significant mortality (8.3%) and morbidity (16.6%) and a significantly greater incidence of recurrence (16.6%). Umbilical herniorrhaphy in patients with functioning peritoneovenous shunts was associated with minimal morbidity (7%). These data suggest that cirrhotic patients with ascites who require an umbilical herniorrhaphy preferably should undergo peritoneovenous shunting before repair of the hernia.

CT and MR of temporal bone malignancies primary and secondary to parotid carcinoma.

PURPOSE: To review the CT and MR characteristics of temporal bone malignancy, and to evaluate the relationship between malignancies of the temporal bone and parotid gland. METHODS: A group of 15 surgical patients with diagnosis of temporal bone malignancy were retrospectively reviewed. These included 11 cases of primary temporal bone malignancy and four cases of secondary carcinoma of the temporal bone from a primary tumor of the parotid gland. Three primary temporal bone malignancies were recurrences, and two secondary tumors were parotid recurrences. RESULTS: Five of the 11 patients with primary temporal bone malignancy had parotid infiltration (45%). All four patients with secondary temporal bone destruction caused by parotid carcinoma had erosion of the mastoid, two with erosion of the external auditory canal, and one of the middle ear. CONCLUSIONS: It is important radiographically to recognize the close relationship between malignancies of the temporal bone and parotid gland, because either may secondarily invade the other. Suspicion of malignancy in either the temporal bone or parotid gland necessitates complete imaging of the other structure. Temporal bone or skull base erosion were best seen on CT at bone algorithm. MR with and without infusion provided excellent delineation of soft-tissue tumor margins, muscle infiltration, intracranial extension, and vascular encasement.

Epithelial tumors of the paranasal sinuses and nasal cavity.

This article addresses the various epithelial tumors of the nasal cavity and paranasal sinuses. It emphasizes the radiologic evaluation of patients with these tumors and the radiologic findings of importance. The advantages and disadvantages of the use of computed tomographic (CT) and magnetic resonance (MR) imaging in this evaluation are stressed.

En bloc resection of an ethmoid carcinoma involving the orbit and medial wall of the cavernous sinus.

The involvement of the cavernous sinus by malignant tumors has limited their surgical treatment. We report here a successful en bloc resection of an invasive ethmoid carcinoma involving the cavernous sinus in a 46-year-old man. To prepare for surgery on this patient, a cadaver study was performed to investigate the feasibility of en bloc cavernous sinus resection and reconstruction. The preoperative evaluation, operative approach, and postoperative management are presented.

Vascular considerations and complications in cranial base surgery.

The technical evolution of cranial base surgery has resulted in approaches that allow more radical surgical extirpation of complex cranial base lesions. Our service has extensively applied these cranial base approaches for lesions of the cranial base. A subgroup of 100 patients who had cranial base tumors involving potential manipulation or sacrifice of carotid arteries underwent 20-minute balloon test occlusions coordinated with vascular assessments consisting of a combination of the following: 1) four-vessel cerebral angiogram with compression studies; 2) occlusion transcranial Doppler ultrasonography; 3) occlusion single-photon emission computed tomography perfusion studies; and 4) xenon-133 cerebral blood flow studies. Transient neurological deficits associated with balloon test occlusion occurred in 7 of 100 patients (7%). Subsequently, 18 patients underwent permanent carotid occlusion by endovascular detachable balloons. Delayed ischemic complications (> 72 h) occurred in 4 of 18 (22%) patients. Additionally, a number of vascular complications not predicted by the balloon occlusion tests and vascular assessments were experienced. Repeat vascular assessments defined the causes and guided treatment of ischemic patients. Ischemic complications were caused by hemodynamic insufficiency, embolization, vasospasm, radiation vasculopathy, and venous anomaly. Our experience leads us to believe that no vascular assessment exists today that can predict the occurrence of vascular complications accurately. The current enthusiasm for cranial base surgery must be tempered with the sober reality that management of cerebrovascular anatomy and physiology remain significant limitations. Consideration of potential cerebrovascular complications is paramount to successful outcome and implementation of cranial base surgery.

Use of vascularized fat from the rectus abdominis myocutaneous free flap territory to seal the dura of basicranial tumor resections.

Resection of large skull base tumors may sometimes result in extirpation defects that are not amenable to local tissue closure. Patients with these tumors require free tissue transfer for closure of the intracranial space after basicranial tumor extirpation. The deep inferior epigastric artery supplies the rectus abdominis muscle and the skin and subcutaneous tissue of the lower abdomen. The closure of massive, central defects can be performed with a free flap designed from the ample rectus abdominis vascular territory. This free tissue donor site has abundant and reliable well-vascularized skin and subcutaneous tissue that can be customized to seal these tenuous areas and provide three-dimensional reconstruction. We have modified the rectus abdominis myocutaneous free flap in seven patients for reconstruction of the skull base. The subcutaneous fat was sculptured to form a soft, vascularized "cork" and was used for obliteration of the irregular deep portions of defects at the midcranial base against the repaired or unrepaired dura. All patients who had the vascularized fat used to obliterate the deep space had successful closure of the defect without cerebral spinal fluid leak. There were two wound infections and one donor-site hernia in this group. The judicious use of the vascular territory of the deep inferior epigastric vessels can accomplish secure three-dimensional reconstruction of the skull base. The flap can be reliably transferred, and the vascularized subcutaneous fat can be used to sequester and seal the dura repair.(ABSTRACT TRUNCATED AT 250 WORDS)

Neurovascular considerations in surgery of glomus tumors with intracranial extensions.

Paragangliomas of the skull base, by virtue of their location, locally infiltrative behavior, and vascular nature, are difficult tumors to resect. Surgical removal is especially complicated when intracranial extensions are encountered. Our experience with a one-stage resection of intracranial extensions of glomus tumors in 20 patients is presented. These 20 patients had a total of 29 paragangliomas: 23 glomus jugulare or tympanicum tumors, 5 carotid body tumors, and 1 pterygopalatine lesion. Ten patients had intradural extension; the other 10 had intracranial extradural tumors. The primary complicating treatment factor was the loss of surgical planes in 6 patients with prior surgery and or radiotherapy. The presence of multiple paragangliomas (20%) and catecholamine secretion by the tumors (15%) complicated surgical treatment as well. Surgical morbidity was primarily related to deficits of lower cranial nerves (50%).

Management of neurovascular complications in extended skull base surgery.

Combined oncologic approaches to the skull base now permit resection of extensive basicranial neoplasms. Despite advances in microsurgical techniques, disabling or life-threatening complications are still encountered in such surgery. Successful management of these sequelae is dependent upon meticulous intraoperative care and compulsive postoperative clinical assessment. Perioperative neurovascular complications were recorded in 154 consecutive skull base procedures. The most frequent severe complication was cerebral edema, which occasionally required surgical intervention. Dysphagia was the most common complication noted in the late postoperative period. Based upon this review, the management and methods found to minimize the incidence of various perioperative neurovascular complications related to extended skull base surgery are described.

Postoperative irradiation of patients with malignant tumors of skull base.

To better understand how to irradiate patients after skull-base surgery, the authors of this study analyzed the tumor recurrence patterns in 22 patients with various malignancies. Of these patients, 13 underwent craniofacial resection, 6 had infratemporal fossa resection, and 3 had temporal bone resection. The entire operative field was irradiated in 8 patients (total-field group), and part of the operative field was irradiated in 14 patients (partial-field group). Tumor regrew within the irradiated area in 25% of the total-field group and 14% of the partial-field group. Tumor appeared outside the operative field in 13% of the total-field group and 57% of the partial-field group. Recurrences appeared in contiguous sites in 5 patients, in the unirradiated scar in 5 patients, and in the lymph nodes in 4 patients. Based on the study findings, the authors state that irradiation of the entire operative field, including scars and potential areas of contiguous spread, may be necessary to maximize local control after skull-base surgery.

The concept of transtympanic injection of fibrin caulk.

Cerebrospinal fluid otorhinorrhea after basilar skull trauma poses a difficult management problem. When conservative techniques fail, more aggressive neurosurgical and otologic procedures are required to control cerebrospinal fluid leakage. We assessed a less invasive method for the repair of traumatic cerebrospinal fluid fistulas. Thirty-one adult Sprague-Dawley rats were used to develop an animal model for the treatment of cerebrospinal fluid leakage. A fistula was created by removing a thin plate of bone from the superior aspect of the rat bulla. The bulla was then plugged with a transtympanic injection of fibrin caulk. Otoscopic and histologic data were collected at selected intervals. Transtympanic injection of fibrin caulk failed to alter significantly the rate of healing of cerebrospinal fluid fistulas. Coagulum retraction, rapid fibrinolysis, and other reasons for failure are explored.

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.

Recurrent laryngeal nerve paralysis associated with thoracic aortic aneurysm.

The association of vocal cord dysfunction with thoracic aortic aneurysm (TAA) has been noted in the cardiovascular and otolaryngologic literature. A retrospective review of 168 cases of TAA was performed in order to: (1) define the natural history of associated recurrent laryngeal nerve paralysis (RLNP) and (2) propose mechanisms for the development of RLNP in operated and nonoperated aneurysms. Of 168 aneurysms, 5% manifested hoarseness secondary to RLNP. All had type I aneurysms. Only one patient regained vocal cord function after surgical treatment of the aneurysm. RLNP developed as a sequela of TAA repair in 12% of the patients managed surgically. RLNP associated with TAA type III repair had a higher incidence of recovery than paralysis that occurred after TAA type I repair (40% vs. 0% recovery). Sixty-six percent of all patients with permanently paralyzed larynges in this series attained glottic competence sufficient to avoid Teflon injection, and 27% of all RLNP associated with TAA in this series required Teflon injection for aspiration, severe dysphonia, or both. Seventeen percent of the patients with vocal cord paralysis associated with TAA recovered within 12 months. Aneurysm classification and pertinent anatomic relationships are discussed with reference to various mechanisms of recurrent laryngeal nerve paralysis.

Glomus vagale tumor: the significance of early vocal cord paralysis.

Glomus body tumors most frequently originate in the middle ear (tympanicum) or on the jugular bulb (jugulare). Tumors that arise from the vagal body account for less than 2.5% of these unique paraganglionic neoplasms. Otologic manifestations of tympanicum and jugulare tumors usually precede or accompany neurologic findings. In reviewing five cases of glomus vagale tumors, the initial symptom of voice change, caused by vocal cord paralysis, preceded the presenting symptoms of hearing loss and tinnitus by an average of 2.5 years. The concept of early cranial nerve involvement by glomus vagale tumors is supported in a literature review. The evaluation of "idiopathic" vocal cord paralysis must include radiographic inspection of the skull base, whereas an accurate, temporal account of presenting symptoms may help distinguish vagal body tumors from other vascular neoplasms of this region.

The perioperative management of the petrous carotid artery in contemporary surgery of the skull base.

Optimal techniques for the preoperative assessment and intraoperative management of the petrous carotid artery remain undefined. While purposeful "avoidance" of this structure may result in partial tumor removal, limited exposure of the petrous carotid artery may lead to inadvertent injury with life-threatening neurovascular sequelae. Twenty-five cases are reported in which surgical manipulation of the petrous carotid artery was necessary to accomplish total tumor removal or gain operative exposure to the skull base. A standard diagnostic radiographic assessment consisted of high-resolution computed tomography, magnetic resonance imaging, and a 4-vessel angiography. Preoperative balloon occlusion of the involved internal carotid artery was performed in four patients. Surgical approaches used in this series were broadly classified as: infratemporal-anterolateral (14), pterional-infratemporal (6), or pterional-anterolateral (5). Intraoperative management of the carotid artery consisted of total decompression in 19 cases, decompression with mobilization in four patients, and resection in two instances. Major neurovascular complications included one stroke and death caused by arterial occlusion, one stroke and death caused by arterial spasm, one stroke caused by brain edema, and one death related to a postoperative carotid hemorrhage. Other nonvascular complications included brain swelling, cranial nerve palsies, dysphagia, ataxia, cerebrospinal fluid fistulae, flap necrosis with wound infection, and pneumocephalus. Invasive and noninvasive methods are outlined for the preoperative assessment of the petrous carotid in cases of advanced skull base disease and intraoperative management options are detailed.

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.

Laryngeal chondrosarcoma as a late-appearing cause of "idiopathic" vocal cord paralysis.

A case of laryngeal chondrosarcoma is presented as a late-appearing cause of idiopathic vocal cord paralysis. Twelve cases are cited from the literature in which the cause of so-called idiopathic vocal cord paralysis was discovered with long-term followup. The natural history of idiopathic vocal cord paralysis is addressed, and recommendations for patient management are discussed.

Improved preservation of facial nerve function in the infratemporal approach to the skull base.

Although the infratemporal approach described by Fisch provides excellent exposure of the jugular foramen, intrapetrous carotid artery, and lateral skull base, the anterior displacement of the seventh cranial nerve often results in temporary facial paralysis. The use of a modified technique for facial nerve mobilization resulted in significant improvement of both early and final facial function. Since that earlier report, continuous intraoperative electrical facial nerve monitoring has been used during the infratemporal approach in 20 additional cases. Immediate postoperative facial function was normal in 93% of the monitored cases and in 70% of the cases in the unmonitored group. More importantly, no patients in the monitored group developed grade V or VI weakness after surgery, whereas 48% of the unmonitored patients had grade V or VI weakness during the early postoperative period. This article will describe how intraoperative facial nerve monitoring is used during infratemporal surgery and will compare early facial function in 31 unmonitored patients with early facial function in 20 monitored procedures.