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The use of open MRI in otorhinolaryngology: initial experience.

Intraoperative imaging in head and neck surgery is a useful tool in many situations. In addition to being helpful for intraoperative orientation, real-time imaging enables visualization of the progress of surgery and the completeness of tumor resection. Regions in the head and neck to which access is difficult, and which therefore have a high incidence of morbidity and risk for the patient, can be approached more easily and safely in an open MRI than in a conventional way. Interventions in the open MRI (Signa SP, 0.5 Tesla) were performed with nonmagnetic instruments and an MR-safe microscope. For intraoperative navigation, the integrated FlashPoint system is helpful, because it allows targeting of the tumor by a calculated virtual line. T1W spin-echo, T2W fast spin-echo, and 3D T1W gradient-echo sequences were used for high-resolution imaging. Real-time imaging is achieved by fast multiplanar spoiled gradient-echo sequences or T2 single-shot fast spin-echo sequences. From 1996 to the present, we biopsied 17 petroclival tumors, performed paranasal sinus surgery in five cases, biopsied two neck masses, and inserted tubes for brachytherapy in 12 cases. No complications were observed. In all surgical procedures, a good resolution was obtained with MRI, especially for soft-tissue structures. The tumor could be targeted exactly, and all specimens revealed the relevant histology. In paranasal sinus surgery, however, the success rate was lower because it was difficult to distinguish blood from pathologic tissue. The insertion of tubes for brachytherapy was successful in all cases. It was possible to apply the tubes parallel to each other, 1 cm apart. Relevant biopsies could be taken of both neck masses. The indications for the use of open MRI in otorhinolaryngology are biopsies of tumors in regions that are difficult to approach, such as the petrous apex and petroclival region, the parapharyngeal space, and the orbit. Furthermore, the open MRI can be useful in paranasal sinus surgery, in the evaluation of tissue resection, and in the detection of the anatomy of delicate structures such as the internal carotid artery, the skull base, and the orbit. In addition, active navigation in the open MRI is possible with the integrated FlashPoint system. The advantage over conventional navigation systems lies in the possibility of real-time imaging, which allows detection of tissue changes occurring during the procedure.

Biopsy↗

Altered levels of calcitonin gene-related peptide (CGRP)-like immunoreactivity of cat lumbar motoneurons after chronic spinal cord transection.

In cats subjected to total spinal cord transection at the lower thoracic level, the calcitonin gene-related peptide (CGRP)-like immunoreactivity (LI) was studied in motoneuron cell bodies in the L6-L7 segments. In transected animals, the CGRP-immunoreactive labeling of the motoneurons was virtually absent. When combining the spinal cord transection with a unilateral rhizotomy of all dorsal roots below the transection, however, an apparently normal labelling pattern of CGRP-LI of the motoneurons was displayed on both sides. Thus, surgical interventions which affect afferent pathways to the motoneurons may have influence on the levels of CGRP-LI in otherwise intact motoneurons.

Animals↗

Nitric oxide and glomerulonephritis.

Glomerulonephritis is a common clinical condition that is caused by immune-mediated injury to the kidney and is characterized by dysfunction of the glomerular capillary filtration barrier. Nitric oxide (NO), a ubiquitous molecule with many biological functions throughout the body, has been evaluated as an inflammatory mediator in these circumstances. NO may induce glomerular injury directly or may act via stimulation of a host of other inflammatory mediators. A variety of experimental models of glomerulonephritis have been studied including those induced by infusion of antibodies to the Thy1.1 antigen or glomerular basement membrane, Heymann nephritis, and autoimmune nephritis. In virtually all of these cases there is evidence of increased NO production. Excessive production of NO by inducible nitric oxide synthase (iNOS), derived from infiltrating immune cells or resident glomerular cells, nearly always is associated with increased glomerular injury. Interventions that inhibit this enzyme result in less proteinuria and diminished glomerular damage. In contrast, NO derived from endothelial nitric oxide synthase (eNOS) may limit glomerular disease by preserving endothelial cell integrity. There are only a limited number of studies that have evaluated the impact of NO in patients with glomerulonephritis. Although the bulk of evidence supports a role of NO as a pro-inflammatory mediator in glomerulonephritis, additional work is needed to show an association between altered NO production and the severity and outcome of disease in patients with this disease. It is hoped that better understanding of the role of NO in glomerulonephritis will lead to the development of therapies to ameliorate the disease.

Animals↗

Developing performance indicators that reflect an expanded view of health: findings from the use of an innovative methodology.

BACKGROUND: The increasing presence of managed health care in the United States has been accompanied by the widespread use of performance indicators to assess health plans along various dimensions of quality. Current performance indicator sets virtually ignore psychosocial and behavioral factors in the prevention and management of illness, especially chronic illness, in spite of documented evidence in the medical literature of the importance of these factors. Instead, current indicator sets focus primarily on biomedical interventions to prevent, treat, and manage illness. METHODOLOGY: In a novel method for developing performance indicators--the use of a storytelling methodology--eight interdisciplinary panels, composed of health care experts at the community, state, and national levels, each completed two stories about patients with chronic illnesses. The first story described experiences a patient might have in the health care system as it is today; the second story retold the events that might transpire if attention to psychosocial and behavioral factors were integrated into the health care system. FINDINGS: Differences between the two sets of stories developed by the panels revealed common themes and specific areas where indicator development might prove fruitful. Performance indicators were identified from these themes, and work is underway to operationalize them; to identify barriers and opportunities for their inclusion in indicator sets; and to further document their potential health and cost-effectiveness. DISCUSSION: Although not scientifically rigorous, the storytelling method was found to provide consistent results and may be applied to many aspects of the health care planning process, health education, and quality improvement efforts.

Community Networks↗

Engineering polydactyl zinc-finger transcription factors.

The availability of rapid and robust methods for controlling gene function is of prime importance not only for assigning functions to newly discovered genes, but also for therapeutic intervention. Traditionally, gene function has been probed by often-laborious methods that either increase the level of a gene product or decrease it. Advances now make it possible to rapidly produce zinc-finger proteins capable of recognizing virtually any 18 bp stretch of DNA--a sequence long enough to specify a unique address in any genome. The attachment of functional domains also allows the design of tailor-made transcription factors for specific genes. Recent studies demonstrate that artificial transcription factors are capable of controlling the expression of endogenous genes in their native chromosomal context with a high degree of specificity in both animals and plants. Dominant regulatory control of expression of any endogenous gene can be achieved rapidly and can be also placed under chemical control. A wide range of potential applications is now within reach.

Animals↗

Sexually transmitted diseases in travelers.

Prevention of sexually transmitted diseases (STDs) is a low priority among travel clinic services, despite increasing evidence that travelers have an increased risk of acquiring such infections. A proportion of 5%-50% of short-term travelers engage in casual sex while abroad, and this rate is even higher among long-term travelers. Few publications are available on STD preventive interventions among travelers. Education and counseling are recognized as key components of risk reduction. New efforts should be put forth with regard to identifying effective tools to promote safer sexual behaviors and to reduce the spread of infection by promoting condom use. Travelers at increased risk should be identified for targeted interventions; research to validate proposed markers of increased risk is prospectively needed. Hepatitis B infection is the only STD that is preventable by vaccination. The feasibility and cost-effectiveness of STD screening in travelers after exposure is a virtually unexplored field, though it may represent an important component of STD control strategies in developed countries.

Biomarkers↗

Novel application of the "doubly labeled" water method: measuring CO2 production and the tissue-specific dynamics of lipid and protein in vivo.

The partitioning of whole body carbon flux between fat and lean compartments affects body composition. We hypothesized that it is possible to simultaneously determine whole body carbon (energy) balance and the dynamics of lipids and proteins in specific tissues in vivo. Growing C57BL/6J mice fed a high-fat low-carbohydrate diet were injected with a bolus of "doubly labeled" water (i.e., (2)H2O and H2(18)O). The rate of CO2 production was determined from the difference between the elimination rates of 2H and 18O from body water. The rates of synthesis and degradation of triglycerides extracted from epididymal fat pads and of proteins extracted from heart muscle were determined by mathematically modeling the 2H labeling of triglyceride-bound glycerol and protein-bound alanine, respectively. We found that mice were in positive carbon balance (approximately 20% retention per day) and accumulated lipid in epididymal fat pads (approximately 9 micromol triglyceride accumulated per day). This is consistent with the fact that mice were studied during a period of growth. Modeling the 2H labeling of triglycerides revealed a substantial rate of lipid breakdown during this anabolic state (equivalent to approximately 25% of the newly synthesized triglyceride). We found equal rates of protein synthesis and breakdown in heart muscle (approximately 10% of the pool per day), consistent with the fact that the heart muscle mass did not change. In total, these findings demonstrate a novel application of the doubly labeled water method. Utilization of this approach, especially in unique rodent models, should facilitate studies aimed at quantifying the efficacy of interventions that modulate whole body carbon balance and lipid flux while in parallel determining their impact on (cardiac) muscle protein turnover. Last, the simplicity of administering doubly labeled water and collecting samples allows this method to be used in virtually any laboratory setting.

Alanine↗

Elimination of vector-borne transmission of Chagas disease.

The control of the vector-borne transmission of Chagas disease in Brazil was organized as a national program in 1975, when two large entomological and sero-epidemiological surveys were conducted in the country in order to identify areas at highest risk of transmission and to guide interventions regarding the chemical treatment of domestic vectors of the disease. The authors present the baseline data gathered through these studies and compare them with more recent data. The evaluation performed shows that the transmission by Triatoma infestans is virtually interrupted and that the transmission by other native species of triatominae from different regions of the country is possibly very low. It is emphasized the need to maintain permanent actions of entomological surveillance in order to prevent recurrent transmission.

Adolescent↗

Psychotherapy for Vietnam-related Posttraumatic Stress Disorder.

There are a wide range of psychotherapeutic treatments for Vietnam-related Posttraumatic Stress Disorder. This paper reviews some of the more commonly used interventions which are the behavioral, psychodynamic, family, and group therapies. Commonalities among these diverse treatments are shown to involve reconfronting trauma stimuli and the attempt to reintegrate traumatic experiences into ongoing personality functioning. It is shown that there are virtually no methodologically sound, empirically based studies that compare two or more treatments within a given study. Experimentally controlled, comparative studies are needed to advance our knowledge of effective treatments of this disorder.

Combat Disorders↗

Tenorrhaphy and tendinous venous envelope (TVE). A morphofunctional study in 24 beagles dogs.

A morphofunctional study was undertaken in 24 Beagle dogs subjected to a a tenorrhaphy, in order to evaluate the results obtained with 3 different surgical procedures (16 hands each)--"traditional" (TRAD); the "tendinous venous envelope" (TVE), and the "simulated procedure" (SHAM). The surgical tissue (n = 48) was the extensor digitorum communis muscle of the hand (forepaw) bilaterally. For TRAD procedure, the Bunnell suture technique was applied. For the TVE procedure, the tenorrhaphy site was wrapped in a segment of autologous femoral vein and for the SHAM procedure, the tendon was exposed over 3 cm without sectioning it and the wound was closed. In each case, the limb was immobilised for 21 days in a cast. Functional data (288 X-rays) was obtained on angle variations of the radio-carpal joint in 2 different positions--passive (physiological), and forced (with an additional weight of 150 g). For each position, the angle variation obtained for each one of the surgical procedures were compared at 3 different times: day zero (surgical intervention), day 21 (cast removal), and day 35 (surgical tissue removal). Morphological data (144 sections) was obtained by analyzing the surgical tissue (tendinous fibrosis; fusion of the tendon clusters with the epimysium and the neighboring tissues; synovitis and the virtual space between the tendon and the neosheath). Tests of variance analysis by posts (critical H = 5.99), showed that the TVE procedure produced better results as compared to TRAD (SHAM approximately equal to TVE > TRAD) on day 21 (H = 22.58) as well as on day 35 (H = 8.08).

Analysis of Variance↗

Adaptive soft tissue deformation for a virtual reality surgical trainer.

Real time tissue deformation is an important aspect of interactive virtual reality (VR) environments such as medical trainers. Most approaches in deformable modelling use a fixed space discretization. A surgical trainer requires high plausibility of the deformations especially in the area close to the instrument. As the area of intervention is not known a priori, adaptive techniques have to be applied. We present an approach for real time deformation of soft tissue based on a regular FEM mesh of cube elements as opposed to a mesh of tetrahedral elements used by the majority of soft tissue simulators. A regular mesh structure simplifies the local refinement operation as the elements topology and stiffness are known implicitly. We propose an octree-based adaptive multiresolution extension of our basic approach. The volumetric representation of the deformed object is created automatically from medical images or by voxelization of a surface model. The resolution of the volumetric representation is independent of the surface geometry resolution. The surface is deformed according to the simulation performed on the underlying volumetric mesh.

Computer Simulation↗

Outbreak of Salmonella infantis infection in a large animal veterinary teaching hospital.

During the past 11 years, there have been numerous reports of outbreaks of salmonellosis involving horses in veterinary teaching hospitals. Some of these outbreaks have been associated with Salmonella serotypes not commonly associated with infection of horses. Salmonella infantis is among the more common Salmonella serotypes isolated from human beings, and is an important pathogen in the broiler chicken industry. However, it was not commonly isolated from horses or cattle on a national basis between 1993 and 1995. In this report, we describe an outbreak of S infantis infection among large animals, primarily horses, in a veterinary teaching hospital and the control measures that were implemented. Factors that appeared to be key in control of this outbreak in this hospital included providing biosecurity training sessions for hospital personnel, adopting a standard operating procedure manual for biosecurity procedures, installing additional handwashing sinks throughout the facility, painting the interior of the facility with a nontoxic readily cleanable paint, replacing the dirt flooring in 4 stalls with concrete flooring, and removing noncleanable surfaces such as rubber stall mats, wooden hay storage bins, and open grain bins. Our experience with this outbreak suggests that although it is virtually impossible to eliminate Salmonella organisms from the environment, minimizing contamination is possible. Prevention of nosocomial infection must be approached in a multifaceted manner and care must be taken to search out covert sources of contamination, especially if standard intervention procedures do not prevent spread of the disease.

Animals↗

Interventional nephrology in Puerto Rico.

Vascular access is emerging as a critical issue for hemodialysis patients in Puerto Rico. In more than 50% of the hemodialysis patients, tunneled hemodialysis catheters are the sole access for providing dialysis therapy. Most disturbing is the fact that a significant number of these catheters are nontunneled temporary catheters, sometimes placed in the subclavian vein. These facts have contributed significantly to the morbidity and mortality seen in chronic dialysis patients. In addition, many cases of early or late dysfunction of arteriovenous access are not detected and treated in a timely manner due to the lack of a comprehensive vascular access program for end-stage renal disease (ESRD) patients. In fact, monitoring programs to identify and detect vascular access dysfunction are virtually nonexistent in many chronic dialysis units. Even when diagnosed, it is not treated in a timely fashion. Recently literature has shown that procedure-related delays in the treatment of patients with renal disease can be minimized and nephrology care more efficiently delivered by a nephrologist trained in nephrology-related procedures. In an effort to optimize the care of our ESRD patients, we took the initiative to develop an interventional nephrology program that effectively deals with vascular access-related procedures in a timely manner. This approach has minimized delays, decreased hospitalizations and the use of temporary catheters, and improved the medical care of our chronic dialysis patients. So far we have performed more than 400 procedures in the 6 months since the initiation of the program. In this article we describe our initial experience with interventional nephrology in Puerto Rico.

Angioplasty, Balloon↗

Use of the Pediatric Symptom Checklist to screen for psychosocial problems in pediatric primary care: a national feasibility study.

BACKGROUND: Routine use of a brief psychosocial screening instrument has been proposed as a means of improving recognition, management, and referral of children's psychosocial morbidity in primary care. OBJECTIVE: To assess the feasibility of routine psychosocial screening using the Pediatric Symptom Checklist (PSC) in pediatrics by using a brief version of the checklist in a large sample representative of the full range of pediatric practice settings in the United States and Canada. We evaluated large-scale screening and the performance of the PSC in detecting psychosocial problems by (1) determining whether the prevalence of psychosocial dysfunction identified by the PSC was consistent with findings in previous, smaller samples; (2) assessing whether the prevalence of positive PSC screening scores varied by population subgroups; and (3) determining whether the PSC was completed by a significant proportion of parents from all subgroups and settings. PATIENTS AND METHODS: Twenty-one thousand sixty-five children between the ages of 4 and 15 years were seen in 2 large primary care networks: the Ambulatory Sentinel Practice Network and the Pediatric Research in Office Settings network, involving 395 pediatric and family practice clinicians in 44 states, Puerto Rico, and 4 Canadian provinces. Parents were asked to complete a brief questionnaire that included demographic information, history of mental health services, the 35-item PSC, and the number of pediatric visits within the past 6 months. RESULTS: The overall prevalence rates of psychosocial dysfunction as measured by the PSC in school-aged and preschool-aged pediatric outpatients (13% and 10%, respectively) were nearly identical to the rates that had been reported in several smaller samples (12%-14% among school-aged children and 7%-14% among preschoolers). Consistent with previous findings, children from low-income families were twice as likely to be scored as dysfunctional on the PSC than were children from higher-income families. Similarly, children from single-parent as opposed to those from 2-parent families and children with a past history of mental health services showed an elevated risk of psychosocial impairment. The current study was the first to demonstrate a 50% increase in risk of impairment for male children. The overall rate of completed forms was 97%, well within an acceptable range, and at least 94% of the parents in each sociodemographic subgroup completed the PSC form. CONCLUSIONS: Use of the PSC offers an approach to the recognition of psychosocial dysfunction that is sufficiently consistent across groups and locales to become part of comprehensive pediatric care in virtually all outpatient settings. In addition to its clinical utility, the consistency and widespread acceptability of the PSC make it well suited for the next generation of pediatric mental health services research, which can address whether earlier recognition of and intervention for psychosocial problems in pediatrics will lead to cost-effective outcomes.

Adolescent↗

Surgical approach in a rare case of coloboma-choristoma.

Embryogenic eyelid defects can be isolated or associated with malformative diseases, such as Tessier craniofacial clefts. We describe the exceptional coexistence of upper eyelid coloboma and lower eyelid dermolipoma in a 45-day-old infant with a Tessier no. 0-1 cleft. The surgical intervention carried out on this patient, which used a flap of subconjunctival choristoma and grafting of reshaped cutaneous and tarsal portions of a preauricular anlage, is presented as a technique for correcting congenital palpebral coloboma. Adoption of this technique allowed virtually complete repair of the defect and gave an acceptable functional and cosmetic result.

Abnormalities, Multiple↗

Computed intraoperative navigation guidance--a preliminary report on a new technique.

OBJECTIVE: To assess the value of a computer-assisted three-dimensional guidance system (Virtual Patient System) in maxillofacial operations. DESIGN: Laboratory and open clinical study. SETTING: Teaching Hospital, Austria. SUBJECTS: 6 patients undergoing various procedures including removal of foreign body (n=3) and biopsy, maxillary advancement, and insertion of implants (n=1 each). INTERVENTIONS: Storage of computed tomographic (CT) pictures on an optical disc, and imposition of intraoperative video images on to these. The resulting display is shown to the surgeon on a micromonitor in his head-up display for guidance during the operations. MAIN OUTCOME MEASURES: To improve orientation during complex or minimally invasive maxillofacial procedures and to make such operations easier and less traumatic. RESULTS: Successful transferral of computed navigation technology into an operation room environment and positive evaluation of the method by the surgeons involved. CONCLUSIONS: Computer-assisted three-dimensional guidance systems have the potential for making complex or minimally invasive procedures easier to do, thereby reducing postoperative morbidity.

Adult↗

Teaching Surgical Hysteroscopy with a Computer

Using a hysteroscope can be simulated on a computer. It will improve physician training by measuring basic knowledge and abilities, allow different interventions and anatomic variations, minimize the trauma of surgical intervention, and reduce operative casualties. An integrated questionnaire covers instrumentation, fluid infusion, power source, indications and preparation for endometrial ablation, surgical techniques, and complications to evaluate the user's knowledge. The operation simulation then proceeds. In the endometrial cavity, by virtual simulation, the operating field should appear in real time to allow physicians to adapt the trajectory of the instruments. The computer is an IBM PC compatible. We use a modified joystick with optical encoders to know the instrument position. The simulation can be repeated as desired. An evaluation system is integrated in the software to keep the user informed on the amount of burn area(s) that have been completed. This prototype model is available.

Journal Article↗

Investigating the mechanisms of retinal degenerations with antisense oligonucleotides.

Utilizing antisense oligonucleotides coupled with an intact Xenopus eye rudiment model, we have effectively demonstrated that we are able to downregulate the expression of a photoreceptor-specific protein, rds/peripherin, and generate a loss-of-function model upon which to further study the function of the rds/peripherin gene. The ultrastructure and protein expression patterns very closely resemble those previously documented in both the rds mouse and in human autosomal dominant retinitis pigmentosa due to peripherin/RDS mutations. An identical strategy can be applied to any gene correlated with a degenerative retinal phenotype. As the entire array of genes is revealed through the various genome projects, including human and mouse, it is becoming increasingly critical to evaluate and determine the function of the corresponding gene products. Discovering which gene is responsible for a particular clinical phenotype is only the first of many steps in the development of a treatment or cure for that particular disease. Using our in vitro model, in which the retina is readily accessible to the antisense oligonucleotide yet the normal three-dimensional ultrastructure of the retina is maintained, we can evaluate the function of virtually any gene as the sequence becomes available. A thorough understanding of the function of individual genes will provide insights on the role of gene product in retinal health and pathophysiology. This experimental approach will also allow for specific therapeutic interventions to be evaluated so that targeted treatments can be designed for individuals with specific genetic mutations.

Animals↗