Structural and functional changes in the cristae ampullares of aged gerbils.

We have reported that calretinin and calbindin staining of calyxes in the apical region of the cristae is reduced or absent in old gerbils (>or=35 months) that had normal numbers of hair cells [Kevetter GA, Leonard RB (2002) Decreased expression of calretinin and calbindin in the labyrinth of old gerbils. Brain Res 957:362-365]. Here we examine the ability of primary afferents in aged gerbils to carry a tracer injected into the vestibular nuclear complex to their terminals in the cristae. Calyxes throughout the cristae were well labeled in a young animal with such an injection. In the aged animals, many calyxes were only partially filled or not filled at all. In some cases labeled axons were also missing from the stroma underlying the missing calyxes. There is a strong correspondence between the region where the calyxes were not filled and the absence of calretinin immunostaining. To determine if afferents from the cristae are functionally abnormal, we recorded from their axons and attempted to activate them with natural stimulation. Among afferents that could be activated, we encountered many afferents that had spontaneous activity but could not be modulated with natural stimulation. When tested, the firing rate of these afferents could be modulated with galvanic stimulation, and/or they could be activated by pulsed electrical stimulation. We also encountered afferents that had no spontaneous activity. The presence of these axons was revealed by an injury discharge that could not be modulated with natural stimulation. When tested, these axons could be activated with pulsed electrical stimulation. In some instances we encountered two or more such afferents in a row, an event we have not seen in young animals. We suggest that the simplest explanation for these observations is that calyxes are being lost in old animals.

Muscarinic acetylcholine receptor subtype expression in avian vestibular hair cells, nerve terminals and ganglion cells.

Muscarinic acetylcholine receptors (mAChRs) are widely expressed in the CNS and peripheral nervous system and play an important role in modulating the cell activity and function. We have shown that the cholinergic agonist carbachol reduces the pigeon's inwardly rectifying potassium channel (pKir2.1) ionic currents in native vestibular hair cells. We have cloned and sequenced pigeon mAChR subtypes M2-M5 and we have studied the expression of all five mAChR subtypes (M1-M5) in the pigeon vestibular end organs (semicircular canal ampullary cristae and utricular maculae), vestibular nerve fibers and the vestibular (Scarpa's) ganglion using tissue immunohistochemistry (IH), dissociated single cell immunocytochemistry (IC) and Western blotting (WB). We found that vestibular hair cells, nerve fibers and ganglion cells each expressed all five (M1-M5) mAChR subtypes. Two of the three odd-numbered mAChRs (M1, M5) were present on the hair cell cilia, supporting cells and nerve terminals. And all three odd numbered mAChRs (M1, M3 and M5) were expressed on cuticular plates, myelin sheaths and Schwann cells. Even-numbered mAChRs were seen on the nerve terminals. M2 was also shown on the cuticular plates and supporting cells. Vestibular efferent fibers and terminals were not identified in our studies. Results from WB of the dissociated vestibular epithelia, nerve fibers and vestibular ganglia were consistent with the results from IH and IC. Our findings suggest that there is considerable co-expression of the subtypes on the neural elements of the labyrinth. Further electrophysiological and pharmacological studies should delineate the mechanisms of action of muscarinic acetylcholine receptors on structures in the labyrinth.

Performance improvement: the organization's quest.

In today's health care marketplace, quality has become an expectation. Stakeholders are demanding quality clinical outcomes, and accrediting bodies are requiring clinical performance data. The Roosevelt Institute's quest was to define and quantify quality outcomes, develop an organizational culture of performance improvement, and ensure customer satisfaction. Several of the organization's leaders volunteered to work as a team to develop a specific performance improvement approach tailored to the organization. To date, over 200 employees have received an orientation to the model and its philosophy and nine problem action and process improvement teams have been formed.

Investigation of an outbreak of vancomycin-resistant Enterococcus faecium in a low prevalence university hospital.

BACKGROUND: Until 1995, there were no cases of vancomycin resistant enterococcus (VRE) identified at our university hospital. From May 1995 to August 1996, we investigated a cluster of 10 cases of phenotypic class Van B Enterococcus faecium. METHODS: Patients were matched with controls who were on the same unit for at least 7 days prior to the case developing VRE. Control patients were age and sex matched if possible, and had duration of hospitalization at least as long as the number of days it took the patient to become VRE positive. We analyzed 16 independent risk factors using Epi-info version 6. Environmental cultures were obtained in the MICU where 5 of the patients were located. All 10 patient isolates and environmental isolates were analyzed by pulsed field gel electrophoresis (PFGE). RESULTS: PFGE confirmed the genetic relatedness of all 10 patient isolates and environmental isolates. The VRE-positive group was more likely to be immunosuppressed and to have exposure to 3 physicians. In the MICU, significant, P < 0.05) risk factors for VRE were higher Apache scores, location adjacent to a VRE case, duration of vancomycin and amino-glycoside use, duration of invasive catheter use, and diarrhea. Among the VRE-positive environmental cultures was a blood pressure cuff wash that was used on several patients. CONCLUSION: We hypothesize that a VRE strain was introduced into our hospital environment and was spread by personnel or contaminated equipment. As a consequence of this study, a hospital-wide VRE policy was implemented.

Use of calcium-binding proteins to map inputs in vestibular nuclei of the gerbil.

We wished to determine whether calbindin and/or calretinin are appropriate markers for vestibular afferents, a population of neurons in the vestibular nuclear complex, or cerebellar Purkinje inputs. To accomplish this goal, immunocytochemical staining was observed in gerbils after lesions of the vestibular nerve central to the ganglion, the cerebellum, or both. Eleven to fourteen days after recovery, the brain was processed for immunocytochemical identification of calretinin and calbindin. After lesion of the vestibular nerve, no calretinin staining was seen in any of the vestibular nuclei except for a population of intrinsic neurons, which showed no obvious change in number or staining pattern. Calbindin staining was reduced in all nuclei except the dorsal part of the lateral vestibular nuclei. The density of staining of each marker, measured in the magnocellular medial vestibular nucleus, was significantly reduced. After the cerebellar lesion, no differences in calretinin staining were noted. However, calbindin staining was greatly reduced in all nuclei. The density of staining, measured in the caudal medial vestibular nucleus, was significantly lower. After a combined lesion of the cerebellum and vestibular nerve, the distribution and density of calretinin staining resembled that after vestibular nerve section alone, whereas calbindin staining was no longer seen. This study demonstrates that calretinin and calbindin are effective markers for the identification of vestibular afferents.

Medical outreach after hurricane Marilyn.

INTRODUCTION: Many geographical areas are subject to devastating disasters that leave the citizens not only without homes, but also without their local medical systems. Now medical-aid stations consisting of personnel, supplies, and equipment quickly can be deployed when needed to such areas under the aegis of the National Disaster Medical System (NDMS). Such teams can provide emergent medical care as well as daily medical care. However, these aid stations are of no help for the home-bound or nursing home patients too infirm to reach them. Thus, these citizens only can obtain medical care if medical teams make planned outreach excursions to reach them. OBJECTIVE: To describe a planned outreach program that was implemented for such patients on St. Thomas Island after it was devastated by Hurricane Marilyn in 1995. RESULTS: Over a five-day period, the outreach team provided medical care for 67 patients ranging in age from 11 days to 90 years. Play and art therapy was provided for non-injured children. The most common needs in the elderly were anti-hypertensive medications and insulin-loaded syringes. CONCLUSIONS: For outreach efforts of this nature, membership of the team should include a registered nurse, a paramedic, a respiratory therapist, a public health specialist, and a local authority familiar both with the area and its inhabitants. A physician does not need to be assigned to the team, but should be available by radio.

Characterization of endemic strains of Shigella sonnei by use of plasmid DNA analysis and pulsed-field gel electrophoresis to detect patterns of transmission.

Shigellosis is hyperendemic in Utah. Most isolates are Shigella sonnei, making it difficult to identify epidemiologic clustering. To better define transmission, molecular markers and epidemiologic data were examined for 90 cases. Plasmid analysis and pulsed-field gel electrophoresis (PFGE) of the S. sonnei isolates identified 11 and 4 patterns, respectively. Plasmid pattern I infections occurred in 8 day care centers over a 6-month period, suggesting spread between centers. Plasmid pattern III was isolated from children at 3 additional centers and pattern IV was associated with another day care center, suggesting different outbreaks. By PFGE, plasmid groups I and XI appeared identical, as were plasmid groups II and V; plasmid group X had a unique pattern. Plasmid groups III, IV, and VII-IX were closely related PFGE subtypes. Both plasmid analysis and PFGE allow better characterization of S. sonnei transmission patterns of "endemic" strains and could lead to improved control measures.

Rapid lysis of gram-positive cocci for pulsed-field gel electrophoresis using achromopeptidase.

To adapt pulsed-field gel electrophoresis (PFGE) to a busy clinical laboratory, we evaluated the use of achromopeptidase (ACP) as the sole agent for lysis of a variety of gram-positive cocci. Growth in an appropriate broth media was adjusted to a 3.0 McFarland density before aliquotting for washing and plug preparation. ACP incorporated into the agarose plugs, or added to the buffer solution, lysed cells in < 1 h when suspended in a Tris-NaCl buffer. Two 30-min washes in a Tris-EDTA buffer were sufficient to remove cellular debris without additional deproteination. Final PFGE results were obtained in approximately 48 h, including the initial broth subculturing.

Rapid detection of the staphylococcal mecA gene from BACTEC blood culture bottles by the polymerase chain reaction.

A rapid polymerase chain reaction (PCR) method for the direct detection of the staphylococcal mecA gene from BACTEC blood culture bottles (Becton Dickinson, Sparks, MD) was developed. Published primer sequences and sample preparation using Achromopeptidase for cell lysis were adapted to the use of the Idaho Technology Air Thermocycler 1605 (Idaho Technologies, Idaho Falls, ID). The method was validated with 80 strains of coagulase-positive and coagulase-negative geographically diverse methicillin-resistant and susceptible isolates of staphylococci. There was a 100% correlation between the PCR results and the results of standard susceptibility testing methods. From BACTEC 9240 blood cultures, mixed aliquots of blood and broth containing gram-positive cocci in clusters were centrifuged at low speed to sediment red blood cells. After additional centrifugation and wash steps, PCR was performed on the resuspended pellet. The turnaround time from initial Gram stain detection of positive BACTEC bottles to PCR amplicon detection by agarose gel electrophoresis is less than 3 hours. In a clinical evaluation of 181 blood culture isolates, there was a 99% correlation with standard susceptibility results for Staphylococcus aureus. Discrepant results for Staphylococcus aureus isolates were verified by a Mueller Hinton plate supplemented with 6 microg/mL of oxacillin and 2% sodium chloride. For coagulase-negative staphylococci, the PCR method detected an additional seven resistant isolates that were reported by the Vitek as susceptible. Coagulase-negative staphylococcal susceptibility results that were in disagreement with the PCR assay were confirmed by the disk-diffusion method. This procedure is accurate, rapid and fits well into laboratory work flow. Rapid detection of the mecA gene on positive blood culture vials has become a routine test in the authors' clinical microbiology laboratory.

Medical support for mass gatherings.

Fairs, concerts, parades, and rallies are some of the many events that cause large numbers of people to gather in one place. Whether the event lasts a day or a week, it is evident that the people attending may require organized medical care. Most of the medical needs are minor, but cardiac arrests and other serious medical problems, including trauma, must be dealt with by the medical team. Careful planning and integration of emergency physician efforts with local hospitals and the emergency medical services system allow for an optimal delivery of health care, from the routine incident to a mass-casualty event.

Comparison of MIDI Sherlock system and pulsed-field gel electrophoresis in characterizing strains of methicillin-resistant Staphylococcus aureus from a recent hospital outbreak.

An outbreak of methicillin-resistant Staphylococcus aureus infections at the University of Utah Health Sciences Center occurred over a 7-month period. While the isolates phenotypically appeared to be similar in gross morphology and have similar Vitek antibiotic susceptibility patterns, two additional methods of strain characterization were evaluated to enhance the epidemiological investigation: pulsed-field gel electrophoresis and gas chromatography with the MIDI Sherlock system. Sherlock uses gas chromatography to qualitatively and quantitatively analyze the cellular fatty acid composition of organisms and creates two-dimensional plots based on principal-component analysis to define groups of closely related organisms. All isolates were also evaluated by digesting their chromosomal DNAs with the low-frequency-cutting enzyme SmaI and separating the restriction fragments by contour-clamped homogeneous electric field gel electrophoresis. Sample preparation for this pulsed-field gel electrophoresis included a novel cell lysis procedure involving achromopeptidase, greatly reducing the turnaround time. Isolates tested were recovered from the following: 45 suspected outbreak patients, 6 hospitalized patients believed to be unrelated to the outbreak, 6 patients from outside the hospital, and one health care practitioner implicated in the outbreak. Of 45 phenotypically similar suspect strains, 43 clustered tightly on the Sherlock two-dimensional plot. All outbreak patient isolates were also identical by pulsed-field gel electrophoresis with the exception of the same two outliers identified by Sherlock. In this epidemiologic investigation, we found an excellent correlation between the Sherlock and pulsed-field gel electrophoresis results for strain characterization of methicillin-resistant S. aureus.

Comparison of "gram-sure" with vancomycin disks in distinguishing between gram-negative and gram-positive rods.

A study was performed to compare Gram-Sure (JRGA Diagnostics, Rancho Dominguez, CA) with vancomycin disk susceptibility (5 micrograms and 30 micrograms) for clarification of the Gram reaction. Eighty-eight isolates representing 14 gram-negative and gram-positive genera were tested. Gram-Sure was superior to vancomycin susceptibility as a predictor of the Gram reaction in a select group of difficult organisms.

Patient-data collection system used during medical operations after the 1994 San Fernando Valley-Northridge earthquake.

INTRODUCTION: In large disasters, such as earthquakes and hurricanes, rapid, adequate, and documented medical care and distribution of patients are essential. METHODS: After a major (magnitude 6.7 Richter scale) earthquake occurred in Southern California, nine disaster medical assistance teams and two Veterans Administration (VA) buses with VA personnel responded to staff four medical stations, 19 disaster-assistance centers, and two mobile vans. All were under the supervision of the medical support unit (MSU) and its supervising officer. This article describes the patient-data collection system used. All facilities used the same patient-encounter forms, log sheets, and medical treatment forms. Copies of these records accompanied the patients during every transfer. Centers for Disease Control and Prevention data classifications were used routinely. The MSU collected these forms twice each day so that all facilities had access to updated patient flow information. RESULTS: Through the use of these methods, more than 11,000 victims were treated, transferred, and their cases tracked during a 12-day period. CONCLUSIONS: Use of this system by all federal responders to a major disaster area led to organized care for a large number of victims. Factors enhancing this care were the simplicity of the forms, the use of the forms by all federal responders, a central data collection point, and accessibility of the data at a known site available to all agencies every 12 hours.

Posterior sternoclavicular dislocation: a case report.

Posterior sternoclavicular dislocation is a relatively rare form of trauma, but one that must be recognized by the emergency physician. Such a case is presented here. Due to the proximity of the clavicle to critical thoracic outlet structures, serious complications can arise from a posterior dislocation: impingement on and possible trauma to the trachea, pneumothorax, laceration of underlying great vessels, brachial plexus injury, esophageal trauma, and laryngeal trauma that may cause permanent vocal cord changes. Many of these potential complications are life-threatening, and it is important that this injury not be triaged in the emergency department as a minor injury, thereby leading to its improper or delayed treatment.