Electrical and optical spectroscopy for quantitative screening of hepatic steatosis in donor livers.

Macro-steatosis in deceased donor livers is increasingly prevalent and is associated with poor or non-function of the liver upon reperfusion. Current assessment of the extent of steatosis depends upon the macroscopic assessment of the liver by the surgeon and histological examination, if available. In this paper we demonstrate electrical and optical spectroscopy techniques which quantitatively characterize fatty infiltration in liver tissue. Optical spectroscopy showed a correlation coefficient of 0.85 in humans when referenced to clinical hematoxylin and eosin (H&E) sections in 20 human samples. With further development, an optical probe may provide a comprehensive measure of steatosis across the liver at the time of procurement.

Managing wildlife populations with uncertainty: cormorants Phalacrocorax carbo.

Managing wildlife populations for conservation, control or harvesting involves uncertainty. Nevertheless, decisions need to be made based on the available evidence. The two main sources of uncertainty in population modelling are parameter estimates and structural uncertainty. Structural uncertainty in models is not included as often as parameter uncertainty.We present an approach where parameter and structural uncertainty (strength of density dependence) is included within a model, using the over-wintering English population of cormorants Phalacrocorax carbo L. Because of the damage caused to inland fishery interests by cormorants, there was a change in UK government policy in autumn 2004, increasing the numbers of birds that can be shot under licence.A stochastic Monte Carlo annual population model was produced to examine the effect of changes to the numbers of birds shot each year. Indices of annual population size were converted to population estimates and used to determine annual growth rates and strength of density dependence.There is strong evidence for density dependence in the data, which suggests the population is currently slightly above carrying capacity, with a mean growth rate of 4-6% per annum. The 1300 birds shot under licence in 2004/05 represent about 4.5% of the English population, and if this level of culling continues, the population would be expected to decline by 9% by 2007, compared to the long-term average. The a priori preferred model, which included all uncertainty, gave predictions for 2004/05 and 2005/06 in close agreement with field data.The model was used to produce short-term population projections, with the understanding that Adaptive Resource Management (ARM) will be adopted to iteratively update the parameters and model each year, feeding back into the numbers of available licences.Synthesis and applications. We recommend the approach used in this study of including parameter and structural uncertainty within a single model, where possible, with the proportion of iterations that utilize a particular structure dependent on the weight of evidence for that structure. This will produce results with wider confidence intervals, but ensures that the evidence for any particular model is not over-interpreted.

Compression of the intervertebral disc with combined flexion and torsion

Bovine caudal motion segments were used to investigate the loss of load-bearing ability under both quasi-static and cyclic loading. 80 motion segments dissected from 41 bovine tails were subjected to quasi-static and cyclic compression...

Rupture of intervertebral disc under internal pressurization

Bovine caudal motion segments were used to investigate the intrinsic failure strenght of the intect intervertebral disc under internal hydrostatic pressure...

Oral administration of formalin-inactivated cells of Aeromonas hydrophila A3-51 controls infection by atypical A. salmonicida in goldfish, Carassius auratus (L.).

There has been increasing interest in the use of probiotics in aquaculture to control fish diseases (e.g. Douillet Langdon 1994; Gildberg, Mikkelsen, Sandaker & Ringo 1997; Kennedy, Tucker, Neidic, Vermeer, Cooper, Jarrell & Sennett 1998; DeSchrijver & Ollevier 2000; Robertson, O'Dowd, Burrells, Williams & Austin 2000), and a diverse range of Gram-positive (such as Carnobacterium inhibens) (Robertson et al. 2000) and Gram-negative bacteria, including Vibrio alginolyticus (Garriques & Arevalo 1995), have been evaluated at various times. However, the possible use of probiotics to control diseases of ornamental fish has been neglected. Consequently, following previous success with live (Irianto & Austin 2002) and inactivated probiotics in salmonids (Irianto & Austin, in press), research has focused on the usefulness of inactivated bacterial preparations for the control of atypical Aeromonas salmonicida infections in goldfish, Carassius auratus (L.). Goldfish, of average 40-50 mm in length, were obtained from a commercial farm in England, and maintained in aerated re-circulating dechlorinated fresh water at 17 degrees C. Their health status was examined immediately upon arrival in the aquaria and at 1-2-week periods thereafter (after Austin & Austin 1989).

Recovery of a new biogroup of Yersinia ruckeri from diseased rainbow trout (Oncorhynchus mykiss, Walbaum).

Cultures of a new biogroup of Yersinia ruckeri, the causal agent of enteric redmouth (ERM), were recovered in England from diseased rainbow trout (Oncorhynchus mykiss, Walbaum), which had been previously vaccinated with a commercial ERM vaccine. The bacterial isolates were confirmed as Y. ruckeri by the results of sequencing the 16S rRNA, but differed from the characteristics of the taxon by positivity for the Voges Proskauer reaction and a general lack of motility, and could not be equated with any of the existing serovars. Cultures were pathogenic in laboratory-based infectivity experiments with 100% mortalities occurring in juvenile rainbow trout (average weight = 10 g) within 4-days of intraperitoneal or intramuscular injection with 10(5) cells/fish. Protection against disease was achieved using a formalin-inactivated whole vaccine prepared against a representative isolate.

PCR and molecular detection for differentiating Vibrio species.

Vibriosis is an economically important disease of fish, marine invertebrates (particularly penaeid shrimps), and large marine mammals and is responsible for high mortality rates in aquaculture worldwide. Some Vibrio species are also responsible for zoonoses, whereas others are relatively nonpathogenic. Using 16S- and 23S-based PCR reactions, we obtained species-specific patterns and a 470-bp band, respectively. DNA sequences obtained on the 23S rRNA gene allowed us to identify species-specific probes for Vibrio parahaemolyticus, V. alginolyticus, V. anguillarum and for a cluster of taxonomically related species: V. carchariae/harveyi/campbelii. A phylogenetic tree based on the 23S sequences confirmed previous results obtained by Western blotting.

A Staphylococcus aureus paraspinal abscess associated with epidural analgesia in labour.

A case is described in which a parturient developed a Staphylococcus aureus paraspinal abscess following epidural analgesia in labour. We compared this case with other reported cases of paraspinal abscesses in obstetric patients. The presentation, diagnosis and management of these cases were reviewed. Anaesthetists need to be aware that non-spinal-epidural abscesses can occur in patients with an associated labour epidural.

Natural history of posterior iliac crest bone graft donation for spinal surgery: a prospective analysis of morbidity.

STUDY DESIGN: A prospective study was conducted to examine bone graft donor site morbidity in 106 consecutive patients undergoing posterior spinal fusion. OBJECTIVES: To perform a prospective analysis of donor site morbidity, to document the incidence of major complications, and to collect information on the impact of autologous bone graft harvesting from the posterior iliac crest on the overall outcome of spinal surgery. SUMMARY OF BACKGROUND: Bone graft harvesting from the posterior iliac crest for spinal fusion is a source of significant morbidity. Previous retrospective case studies indicate that minor complications are common, but they do not define the natural history and complications of posterior iliac crest bone graft harvesting. METHODS: A standardized harvesting technique was used. At 3, 6, and 12 months after surgery, the patients completed a proforma questionnaire rating symptoms on a visual analog scale and underwent a postoperative examination by the surgeon. Finally, overall surgical outcome was assessed at 12 months. RESULTS: The major component of morbidity is donor site pain. Mean pain scores were 1.640 at 3 months, 1.812 at 6 months, and 1.207 at 12 months. The pain at 12 months was significantly less than at 3 and 6 months (P = 0.005), with a trend toward the highest scores at 6 months. A pain score of 0 was reported by 55% of the patients. Local sensory loss was found in 10% of the patients. Outcome assessment showed significant differences in morbidity for surgery performed at different spinal levels (P = 0.001), with lumbosacral surgery resulting in worse outcomes than either cervical (P < 0.05) or thoracolumbar (P < 0.05) surgery. Significantly higher visual analog scores were observed at 6 months in patients with poorer overall outcomes. CONCLUSIONS: According to this study, it is reasonable to reassure patients that a good result from spinal surgery will not be compromised by severe symptoms or major morbidity secondary to posterior iliac crest bone graft donation. Before surgery, patients may be advised concerning the risks of donor site pain, which improves significantly by 12 months, local tenderness, and uncommonly localized sensory loss.

Biomechanical factors influencing nuclear disruption of the intervertebral disc.

STUDY DESIGN: A disc model with full anular division was used to investigate how different biomechanical parameters influence the severity of nuclear disruption during compressive loading. OBJECTIVE: To quantify the manner in which flexion, hydration, and loading rate contribute to the breakdown in the intrinsic cohesive structure of the nucleus pulposus. SUMMARY OF BACKGROUND DATA: The risk of disc herniation is known to increase when the disc is loaded in flexed positions. However, there is a lack of experimental data showing how a combination of flexion with different loading rates and hydration levels affects the extent of nuclear disruption. METHODS: A reproducible state of full hydration was established for isolated bovine caudal discs. A period of static preloading at an applied stress of 1 MPa was used to obtain a consistent state of partial hydration. Then 96 discs were subjected to a full-thickness division of the anulus fibrosus and compressed while hydration level, degree of flexion, and rate of loading were varied systematically. RESULTS: A full spectrum of nuclear damage was observed in the tests, ranging from no detectable disruption to sudden sequestration of the entire nucleus. These results were quantified, and a general correlation was established between the severity of disruption and the different loading parameters. CONCLUSIONS: The degree of flexion and the level of hydration were shown to play an important role in influencing the tendency of the nucleus to break loose and extrude through a preexisting anular division. Interestingly, the rate of loading appeared to have only a minor effect on the severity of damage induced in discs that incorporated a full depth anular division.

Medical malpractice: the effect of doctor-patient relations on medical patient perceptions and malpractice intentions.

OBJECTIVE: To examine the causal effects of doctor-patient relations and the severity of a medical outcome on medical patient perceptions and malpractice intentions in the event of an adverse medical outcome. DESIGN: Randomized between-subjects experimental design. Patients were given scenarios depicting interactions between an obstetric patient and her physician throughout the patient's pregnancy, labor, and delivery. PARTICIPANTS: One hundred twenty-eight postpartum obstetric patients were approached for participation, of whom 104 completed the study. Main outcome measures Patients' perceptions of physician competence and intentions to file a malpractice claim. RESULTS: Positive physician communication behaviors increased patients' perceptions of physician competence and decreased malpractice claim intentions toward both the physician and the hospital. A more severe outcome increased only patients' intentions to sue the hospital. CONCLUSION: These results provide empiric evidence for a direct, causal effect of the doctor-patient relationship on medical patients' treatment perceptions and malpractice claim intentions in the event of an adverse medical outcome.

Serial salivary estriol to detect an increased risk of preterm birth.

OBJECTIVE: To evaluate serial measurements of salivary estriol (E3) to detect increased risk of spontaneous preterm labor and preterm birth. METHODS: A masked, prospective, multicenter trial of 956 women with singleton pregnancies was completed at eight United States medical centers. Saliva was collected weekly, beginning at the 22nd week of gestation until birth, and tested for unconjugated E3 by enzyme-linked immunosorbent assay. Women were separated into high-risk and low-risk groups using the Creasy scoring system. RESULTS: A single, positive (at or above 2.1 ng/mL) salivary E3 test predicted an increased risk of spontaneous preterm labor and delivery in the total population (relative risk [RR] 4.0, P <.005), in the low-risk population (RR 4.0, P < or =.05), and in the high-risk population (RR 3.4, P =.05). Two consecutive positive tests significantly increased the RR in all study groups, with a dramatic improvement in test specificity and positive predictive value but only a modest decrease in sensitivity. In women who presented with symptomatic preterm labor, salivary E3 identified 61% of those who delivered within 2 weeks, using a threshold of 1.4 ng/mL. CONCLUSION: Elevated salivary E3 is associated with increased risk of preterm birth in asymptomatic women and symptomatic women who present for evaluation of preterm labor.

Chitinases from Vibrio: activity screening and purification of chiA from Vibrio carchariae.

Fourteen species of Vibrio were screened for chitin-induced chitinase activity in culture medium. V. carchariae, V. alginolyticus 283 and V. campbellii showed high levels of activity. Screening on agar plates containing swollen chitin showed high levels of chitinase activity by the same three species, and also by V. fischeri and V. alginolyticus 284. An affinity purification procedure was developed for the chitinase from V. carchariae. The purified chitinase was active as a monomer with M(r) 63,000-66,000, and displayed activity toward polymeric chitin from acetylated chitosan or from crab shells. N-terminal sequence analysis and immunological cross-reactivity confirmed that the enzyme belongs to the group A/chiA family of bacterial chitinases.

Factors influencing obstetric and gynecologic patients' decisions toward medical student involvement in the outpatient setting.

OBJECTIVE: We sought to determine the reasons for obstetric and gynecologic patients' acceptance or refusal of medical student participation in their outpatient care. STUDY DESIGN: A descriptive and analytic cross-sectional study of 180 patients at the University of California, San Francisco, was done to identify factors involved in patient acceptance or refusal of medical student participation in their outpatient obstetric-gynecologic visit. Responses were analyzed by Cochran-Mantel-Haenszel tests for rank order tests of factors involved in the decision to accept or decline medical student participation and chi(2) or Fisher exact tests for comparison of data among different groups. RESULTS: Reasons for accepting medical student involvement included the desire to contribute to the training of future physicians and the desire for the highest standard of care. Reasons for refusing medical student involvement included the protection of patient privacy and the low comfort level with the examination. The acceptance rate for medical students during the obstetric visits was 89.1%, and that during the gynecologic visits was 81.4%. CONCLUSION: Private faculty patients, as well as Medicaid patients, have a high acceptance of both male and female medical students in the obstetric-gynecologic outpatient setting.

Radiation exposure during fluoroscopically assisted pedicle screw insertion in the lumbar spine.

STUDY DESIGN: An experimental model to assess radiation exposure during lumbar pedicle screw insertion. OBJECTIVES: To measure skin (patient) and scatter (surgeon) doses of radiation during lumbar spine fluoroscopy to assess safety of the procedure for both the surgeon and patient and determine best practice. SUMMARY OF BACKGROUND DATA: Fluoroscopy assists with accuracy of pedicle screw placement, yet the optimal technique of C-arm use and risk to both patient and operating room staff from radiation exposure are unknown. METHODS: Entry- and scatter-dose recordings were made using a digital dosimeter while screening an anthropomorphic phantom prone on a radiolucent operating table. The source was positioned both superiorly and inferiorly with the height varied in the latter orientation to create a working space under the C-arm. The senior author's fluoroscopy records were reviewed in 140 consecutive cases. RESULTS: In a series of 140 patients who underwent pedicle screw fixation, the fluoroscopy time was 1.4 minutes per case or 0.33 minutes per screw. In the source-superior position, the effective dose received by the patient was approximately 2.3 mSv per case. In the source-inferior position with a working space of 300 mm, the effective dose was 6.8 mSv. Scatter dose to the surgeon was higher in the source-superior position but was still less than 10% of recommended limits for the hand, thyroid, and eyes. CONCLUSIONS: The source-superior position is the preferred position for pedicle screw screening if a working space is required. Patient exposure is minimized, and surgeon dose is well within current recommendations.

The radiologic anatomy of the lumbar and lumbosacral pedicles.

STUDY DESIGN: An anatomic and radiologic study of lumbar and lumbosacral pedicle anatomy. OBJECTIVES: To define the radiologic anatomy of the lumbar and first sacral pedicle in the coaxial projection. SUMMARY OF BACKGROUND DATA: Fluoroscopic assistance for pedicle screw placement requires radiologic landmarks. The radiologic landmarks have previously been assumed. Detailed study of the correlation between anatomy and radiology is required. METHODS: Lumbar vertebrae and sacra were marked with radiopaque material to demonstrate the pedicle cortical borders. The vertebrae were then imaged in the coaxial projection to determine the correlation between the pedicle cortex and the radiologic image. Pedicle dimensions were recorded. RESULTS: Pedicle dimensions were consistent with known measurements, yet the long axis of the L4 and L5 pedicle ellipse was oblique to the vertical. Consequently, the minor diameter of the pedicle ellipse was considerably less than the measured pedicle width at L5. The radiologic pedicle image was consistently within the true pedicle cortex, by up to 3 mm, and probably represents the inner cortical border of the pedicle. The S1 pedicle has reliable anatomic landmarks, yet only the medial and superior borders were visualized. CONCLUSIONS: The radiologic pedicle image in the lumbar and lumbosacral spine is a reliable guide to the true bony cortex of the pedicle. At S1 the pedicle image is less well correlated with the cortical borders of the pedicle, yet other reliable anatomic landmarks exist.

ACC and back injuries: the relevance of pre-existing asymptomatic conditions.

The purpose of the ARCI (1992) and AI (198) Acts is to cover those who suffered from personal injury by accident. This purpose should not be distorted. This review does not aim to suggest that cover be extended to victims of disease. Equally it is inappropriate that imaging be used to detect asymptomatic, age-related change--or reveal asymptomatic abnormalities that do not place the patient at increased risk of symptoms over the general population--so as to unfairly deny coverage to the victims of accidents. This is particularly important to those who suffer personal injury to the lumbar spine where the cause is wholly or substantially an accident, and in whom, without the specified accident having occurred, personal injury (symptoms and disability) would have not been likely to occur. Physicians managing spinal disorders must correlate clinical findings with imaging studies when planning treatment. Those considering entitlement for cover under third party/ACC provisions must pay close attention to the history and clinical evaluation, correlating these with the investigation findings, and not assume that the abnormalities found on sensitive investigations are the cause of the symptoms.

The role of shared parasites in the exclusion of wildlife hosts: Heterakis gallinarum in the ring-necked pheasant and the grey partridge.

1. A two-host shared-macroparasite model was parameterized from the results of infection and transmission experiments, to investigate whether apparent competition between the ring-necked pheasant (Phasianus colchicus) and the grey partridge (Perdix perdix), mediated via the shared nematode Heterakis gallinarum, could theoretically cause partridge exclusion. 2. Both the model created and the experiments conducted show that the bulk of H. gallinarum infection to partridges, when they occur in the same locations as pheasants, will be from the pheasants and not from the partridges themselves. This is due to R0 for the parasite being 1·23 when infecting pheasants, but only 0·0057 when infecting partridges. Thus, when the pheasant is present in the model the partridge population is impacted by the shared parasite but, when the pheasant is absent, the parasite is lost from the system. 3. Based on best available parameter estimates, the observed impact of H. gallinarum on the grey partridge may be sufficient to cause exclusion when the pheasant is present in the model. This supports the hypothesis that the UK grey partridge decline observed over the past 50 years may be partly due to apparent competition with pheasants. 4. Habitat separation between the two host species, where it decreases the rate of H. gallinarum transmission from the pheasant to the partridge, may allow them to co-exist in the field in the presence of the parasite. We predict, however, that grey partridge exclusion would still occur if separation was less than 43%.

Pedicle screw placement at the sacrum: anatomical characterization and limitations at S1.

Anatomical and biomechanical data have suggested that pedicle screw fixation at the sacrum is optimum in the anteromedial direction into the S1 vertebral body, yet the possibility of posterior iliac crest interference with this screw pathway has been considered but not defined. This study aimed to determine if the anteromedial direction of screw placement into the vertebral body is possible in all cases at S1 and to assess the limiting effect of the posterior iliac crest. Computed tomography scans of the upper sacrum at the S1 pedicle parallel to the sacral endplate were examined in 100 patients. Analysis using a digitizer allowed characterization of an ideal screw pathway with variable screw and screw head diameters in an anteromedial direction into the S vertebral body. The effects of the posterior iliac crest upon these pathways were studied. The study demonstrated that anteromedial placement with bicortical fixation at the vertebral body was theoretically possible in almost all (98.5%) cases. Because the sacral body is often wider than the sacral spinal canal, a straight-ahead screw direction will often achieve placement into the S1 vertebral body, if the starting point for the screw allows screw placement adjacent to the medial border of the S1 pedicle with only 1.5 mm of cortical bone separating the canal and the screw. The space between the posterior iliac crest and the lateral aspect of the screw corridor ranges from a maximum of 52.4 mm to a minimum of 12.8, 6.2, and 0 mm for the 7-, 10-, and 12.5-mm screw corridors. On only three occasions (1.5%) was the ideal screw corridor not possible because of posterior iliac crest overlap. In each case, this occurred only unilaterally and when the widest of the screw corridors (12.5 mm) was used. Both the distance between the posterior iliac crests and the space available for optimum screw placement are greater in females than males.

Determining the sagittal dimensions of the canal of the cervical spine. The reliability of ratios of anatomical measurements.

The ratio of the sagittal diameter of the cervical canal to the corresponding diameter of the vertebral body has been described as a reliable means for assessing stenosis of the canal and detecting those at risk of cervical neuropraxia. The use of ratio techniques has the advantage of avoiding variation in magnification when direct measurements are made from plain radiographs. We examined the reliability of this method using plain lateral radiographs of unknown magnification and CT scans. We also assessed other possible ratios of anatomical measurements as a guide to the diameter of the canal. Our findings showed a poor correlation between the true diameter of the canal and the ratio of its sagittal diameter to that of the vertebral body. No other more reliable ratio was identified. The variability in anatomical morphology means that the use of ratios from anatomical measurements within the cervical spine is not reliable in determining the true diameter of the cervical canal.