Bioluminescent signal system: bioluminescence immunoassay of pathogenic organisms

The Ca(2+)-regulated photoprotein obelin has been examined as a label for bioluminescence immunoassay of infective agents. The hepatitis B virus (HbsAg) and the bacteria Escherichia coli and Shigella sonnei lipopolysaccharide (LPS) were chosen as model antigens. Chemically synthesized obelin-corresponding antibody conjugates were used in a solid-phase microplate immunoassay. The sensitivities achieved by the assay were 0.25 ng/mL for S. sonnei LPS and 0.375 ng/mL for HbsAg. A novel, filter-based immunoassay to determine bacterial admixtures in the environment was proposed. The NanoCeram filters were effectively applied to 'trap' and pre-concentrate pathogens from samples under study for the purposes of further detection and measurement of the absorbed material by bioluminescence immunoassay.

Corrections of magnification and focusing in a cathode lens-equipped scanning electron microscope

One of the well-proven and efficient methods of obtaining a very low-energy impact of primary electrons in the scanning electron microscope is to introduce a retarding field element below the pole piece of the objective lens (OL). It is advantageous to use the specimen alone as the negatively biased electrode (i.e., cathode of the cathode lens). The optical power of the cathode lens modifies some of the standard parameters of the image formation such as relation of working distance to OL excitation or magnification to the scanning coils current, the impact angle of primary electrons, and so forth. In computer-controlled electron microscopes these parameters, particularly with regard to focusing and magnification, can be corrected automatically. Derivation of algorithms for such corrections and their experimental verifications are presented in this paper. Furthermore, a more accurate analytical expression for the focal length of an aperture lens is derived.

Growth inhibition of MCF-7 tumor cell line by phenylacetate linked to functionalized dextran

We investigated the antiproliferative effect of phenylacetate covalently linked to dextran derivatives (DMCBPA conjugates) on human breast cancer MCF-7 cells. We show that free sodium phenylacetate (NaPA) inhibits the cell growth (IC50 = 14 mM), while an important inhibitory effect is observed for DMCBPA conjugates. The IC50 dose of these conjugates is as low as 1.0 mg/ml, corresponding to 1.3 mM of phenylacetate. The precursors, dextran substituted with methylcarboxylate and benzylamide groups, did not affect the growth of MCF-7 tumor cells. We have observed that MCF-7 cell growth inhibition depends on amount of phenylacetate linked to the conjugate. The data indicated that an optimum antiproliferative effect is more significant when the amount of phenylacetate groups present on the dextran backbone is high. Analysis of doubling time by growth kinetics study shows that conjugates have more time-sustained effect than free NaPA. It is noteworthy that the inhibitory effect is observed at non-toxic concentration. Theses conjugates could be considered as acceptable derivatives to prevent tumor progression.

Specimen charging and detection of signal from non-conductors in a cathode lens-equipped scanning electron microscope

This paper concerns the problems connected with the observation of a nonconductive specimen in a scanning electron microscope (SEM) when incident electrons create a surface charge and a corresponding electric field. The special configuration of the cathode lens enables one to control the landing energy of primary electrons via the specimen bias. In the cathode lens, the accelerating electric field at the surface of the specimen combines itself with that of the surface charge in influencing the trajectories of the signal electrons and hence the detected signal level and the possible recapturing of slow secondaries. Recaptured electrons reduce the ultimate positive surface potential, which arises when working below the higher critical energy of electron impact. Computer simulations of electron trajectories were performed for the typical cathode lens configuration and for a model specimen characterized by emission yields similar to those for glass. The simulations brought an extensive set of data about the trajectories of both secondary and backscattered electrons. Furthermore, the data were processed in order to assess the charge balance between the emitted and recaptured electrons as well as the collection efficiency of the detector. The results include values of the ultimate positive surface potential and the detected signal level, both in dependence on the initial energy of the electron impact and the size of the field of view. Finally, the method for the determination of critical energy is reevaluated. This is based on the measurement of the time dependence of the detected signal.

Treatment with cyclosporin A in a patient with Omenn's syndrome

Unless treated with haematopoetic stem cell transplantation, Omenn's syndrome, a rare variant of severe combined immunodeficiency, is associated with a fatal outcome. We describe a male infant showing all the typical features of Omenn's syndrome, who was successfully treated with cyclosporin A to improve clinical condition prior to haematopoetic stem cell transplantation.

Utilisation of a sperm quality analyser to evaluate sperm quantity and quality of turkey breeders

1. A relatively new instrument known as a Sperm Quality Analyzer (SQA) offers a rapid assessment of sperm quality and quantity by providing a sperm quality index (SQI). The SQA measures a combination of the intensity of sperm activity and motile concentration by determining the number and amplitude of sperm movements per second in a capillary tube as detected through light beam interference. 2. Because the SQA has not been tested for its potential use in turkeys, the objective was to determine if the SQA could accurately respond to changes in turkey sperm concentration, viability, and motility in semen collected from turkey breeders. 3. The effect of varying concentrations of sperm on SQI values was evaluated by diluting replicate pools of semen from 4 different aged turkey breeder flocks with saline. Results from all 4 flocks showed that semen dilutions greater than 20-fold resulted in a linear decline in SQI values. 4. Additional in vitro analysis evaluated the effects of turkey sperm viability on the SQI under conditions of constant sperm concentration. Incubated, live sperm was mixed in various proportions with thawed, dead sperm to determine changes in viability. Increased proportions of dead sperm caused a decline in the SQI. 5. To assess sperm motility, turkey semen was incubated under either aerobic (motile) or anaerobic (immotile) conditions. Varied amounts of immotile and motile sperm samples were mixed. A linear increase in the SQI was observed as per cent motile sperm increased. 6. These results indicate that the SQA can respond to differences in turkey sperm concentration, viability, and motility using in vitro analyses.

Use of a sperm quality analyser on semen of turkey breeders to monitor storage time effects and age-related changes during a reproductive cycle

1. A relatively new instrument known as a Sperm Quality Analyzer (SQA) offers a rapid assessment of sperm quality and quantity by providing a sperm quality index (SQI). The SQA measures the intensity of sperm activity and motile concentration by determining the number and amplitude of sperm movements per second in a capillary tube as detected through light beam interference. 2. The objectives of the current study were to determine if the SQA could accurately reflect changes in semen quality that occur with prolonged storage of semen and to determine the variation and change in SQI values among individual breeding male turkeys during their semen production cycle. 3. The effect of storage time on SQI values was evaluated by diluting semen with extender and placing the semen on an oscillating shaker at 4 degrees C for 8 h. The SQI values and sperm viability, expressed as % dead sperm, were recorded hourly. The SQI readings declined linearly with increased storage time while % dead sperm increased linearly with increased semen storage. 4. Semen from 220 individual males was analysed monthly for 9 months. Semen diluted 50-fold with saline had lower SQI values during pre- and post-peak phases of production (months 1, 7, 8, and 9 as compared with months 2 to 6 of semen production). The highest SQI values occurred during months 2 to 6. The largest variation in SQI values occurred during months 1 (CV = 26%) and 9 (CV = 31%) with a CV that averaged 16% for the remaining months. 5. Correlation analysis of SQI values for each bird averaged over 9 months with individual male SQIs for each month showed monthly correlation coefficients that ranged from 0.22 to 0.63. 6. These results indicate that the SQA accurately assessed the decline in sperm quality that occurs with prolonged storage of turkey semen and reflected age-related changes in semen quality and quantity that occurred during a semen production cycle of turkey breeders. In addition, the semen quality rank of some turkey breeders in a population changed with age.

[Long-term results after surgical tracheotomy and percutaneous dilatation tracheostomy. A comparative retrospective analysis]

Besides surgical tracheostoma for treatment of long-term intubation, percutaneous dilatational tracheostomy (PDT) has become available during the last few years. Long-term results of the PDT are rare in the medical literature. This paper reports a retrospective analysis comparing the results after PDT with those after surgical tracheostomy. The methods include subjective evaluation of both techniques by the patients using a standardized questionnaire. It also includes the objective cosmetic result of the outside scar, as well as endoscopic inspection of the larynx and trachea. The patients own evaluation showed a higher content in the PDT group mainly due to the cosmetic result. The objective data confirmed those results. Patients with surgical tracheostomy had an average scar length of 5 cm (2 inches), compared to 1,2 cm (5 inch) in the PDT group. The endoscopic examination showed minor stenosis of the trachea in both groups that were not functionally relevant. The average stenosis of 14% for the PDT was similar to that observed after surgical tracheostomy which was 19%. The choice of the best technique should be made in close cooperation between head- and neck surgeons and anesthesiologists.

Use of a self-report constipation questionnaire with older adults in long-term care

PURPOSE

The Patient Assessment of Constipation (PAC), a symptom and quality-of-life inventory, was developed among community-dwelling adults under age 65. The purpose of this study was to evaluate the feasibility and validity of an interview format of the PAC for older adults residing in long-term care.

DESIGN AND METHODS

The PAC was administered to 24 nursing home residents aged 65 and older. Cognitive interviewing methods were used to evaluate subjects' understanding and interpretation of PAC items.

RESULTS

The PAC interview required an average of 11 min, 15 s, to complete. Administration modifications for this population included rereading Likert anchor points and the stem question for each item. Subject item interpretation was generally accurate, as was interpretation of Likert anchors.

IMPLICATIONS

The PAC is easily administered and well understood by older adult residents in long-term care and provides a brief method for obtaining constipation-specific symptom and quality-of-life data from this population.

Measuring change in quality of life in response to Helicobacter pylori eradication in peptic ulcer disease: the QOLRAD

This study was designed to determine if a new condition-specific quality of life measure, the Quality Of Life in Reflux And Dyspepsia (QOLRAD), was responsive to clinical change over a four-week period when evaluating peptic ulcer disease patients undergoing Helicobacter pylori (Hp) eradication. A secondary aim was to evaluate QOLRAD's psychometric performance. Hp-positive patients with peptic ulcer disease were recruited from primary care and gastroenterology clinics (N = 155). QOLRAD scores improved significantly (P < 0.0001) and mean total score increase was 1.07 points on a 7-point scale among 111 subjects who responded to Hp eradication. Effect sizes were moderate for responders (0.64) and low for nonresponders (0.36). Score changes below 0.60 were associated with the smallest improvement in patient and physician condition rating; scores above 1.2 were associated with the greatest improvement. The QOLRAD demonstrates reliability and validity. Changes in QOLRAD score can be meaningfully related to clinical changes, aiding evaluation of health-related quality of life in peptic ulcer disease.

[Avian Enzephalomyelitis of poultry: Contribution on the reduction of animals during vaccine testing]

The testing of live avian enzephalomyelitis (AE) virus vaccines according to the prescriptions of the European Pharmacopþia (EP) requires a number of animal trials. The purpose of these trials presented is the replacement respectively of two of the animal trials. The first test to be replaced is the virus titration in eggs which includes the observation of the hatching and survival capacity of infected embryos. Therefore a non-competitive ELISA was developed which allows the quantitative determination of AE-virus preparations. The second test to be refined is the efficacy testing of AE-vaccines. The challenge described in the European Pharmacopþia shall be replaced by the quantification of the serological response of the chickens and their progeny after vaccination. Therefore the minimum amount of protecting humoral antibodies has to be defined. First trials compared the pathogenicity of two challenge strains and evaluated the kinetic of maternal antibodies in chickens derived from vaccinated hens.

The economics of selective serotonin reuptake inhibitors in depression: a critical review

The prevalence of depression and the high costs associated with its treatment have increased interest in pharmacoeconomic evaluations of drug treatment, particularly in the 1990s as the use of selective serotonin (5-hydroxytryptamine; 5-HT) reuptake inhibitors (SSRIs) expanded substantially. This review presents results from specific studies representing the key study designs used to address the pharmacoeconomics of SSRI use: retrospective administrative database analyses, clinical decision analysis models, and randomised clinical trials. Methodological considerations in interpreting results are highlighted. In retrospective administrative database analyses, most comparisons have been made between SSRIs and tricyclic antidepressants (TCAs). A few studies have addressed differences between SSRIs. The studies focused on healthcare cost (to payer) and cost-related outcomes (e.g. treatment duration, drug switching). Although SSRIs are generally associated with higher drug acquisition costs than are TCAs, total healthcare costs are at least offset, if not decreased, by reductions in costs associated with use of SSRIs. Although studies from the early 1990s show some advantage for fluoxetine, the results are limited by use of data from shortly after the introduction of paroxetine and sertraline; studies from the mid- 1990s on that compare drugs within the SSRI class show general equivalence in terms of cost. Important methodological advances are occurring in retrospective studies, with selection bias and other design limitations being addressed statistically. Clinical decision analysis models permit flexibility in terms of ability to specify different alternative treatment scenarios and varying durations. Sensitivity analysis aids interpretability, although model inputs are limited by data availability. Results from short term (1 year duration or less) studies comparing SSRIs and TCAs suggest that SSRIs are more cost effective or that there is no difference. Longer term studies (lifetime Markov models) focus more on the impact of maintenance antidepressant therapy and show more mixed results, generally favouring SSRIs over TCAs. The results indicate that the effect of SSRIs is mainly through prevention of relapse. Important assumptions of these models include fewer serious adverse effects and lower treatment discontinuation rates with SSRIs. Naturalistic clinical trials provide greater generalisability than traditional randomised clinical trials. One naturalistic trial found that nearly half of TCA-treated patients switched to another antidepressant within 6 months; only 20% of SSRI-treated patients switched. Cost differences between groups were minimal. These studies indicate few differences in medical costs, depression outcomes and health-related quality of life between TCAs and fluoxetine, although fewer fluoxetine-treated patients switched treatment.

Scanning electron microscopy of nonconductive specimens at critical energies in a cathode lens system

A method for scanning electron microscopy imaging of nonconductive specimens, based on measurement and utilisation of a critical energy, is described in detail together with examples of its application. The critical energy, at which the total electron yield curve crosses the unit level, is estimated on the basis of measurement of the image signal development from the beginning of irradiation. This approach, concentrated onto the detected signal as the only quantity crucial for the given purpose of acquiring a noncharged micrograph, evades consequences of any changes in an irradiated specimen that influence the total electron yield curve and possibly also the critical energy value. Implementation of the automated method, realised using a cathode lens-equipped scanning electron microsope (SEM), enables one to establish a mean rate of charging over the field of view and its dependence on the electron landing energy. This dependence enables one to determine the energy of a minimum damage of the image of the given field of view. Factors influencing reliability and applicability of the method are discussed and examples of noncharged micrographs of specimens from both life and material science fields are presented.

Symptom and health-related quality-of-life measures for use in selected gastrointestinal disease studies: a review and synthesis of the literature

Patient-rated symptom and health-related quality-of-life (HR-QOL) outcomes are important end-points for clinical trials of medical treatments for gastrointestinal (GI) disorders. Based on this review, patient outcomes research is focused on gastroesophageal reflux disease and dyspepsia, with a growing interest in irritable bowel syndrome but little research in gastroparesis. State-of-the-art for patient-rated symptom scales is rudimentary with an abundance of scales and little attention to systematic instrument development or comprehensive psychometric evaluation. Generally, disease-specific HR-QOL measures have been more systematically developed and evaluated psychometrically, but few have been incorporated into clinical trials. More comprehensive outcome assessments are needed to determine the effectiveness of new medical treatments for functional GI disorders. Future clinical trials of GI disorders should combine clinician assessments of outcomes and symptoms with patient-rated symptom and HR-QOL end-points.

Prefrontal, parietal, and temporal cortex networks underlie decision-making in the presence of uncertainty

Decision-making in the presence of uncertainty, i.e., selecting a sequence of responses in an uncertain environment according to a self-generated plan of action, is a complex activity that involves both cognitive and noncognitive processes. Using functional magnetic resonance imaging, the neural substrates of decision-making in the presence of uncertainty are examined. Normal control subjects show a significant activation of a frontoparietal and limbic neural system during a two-choice prediction task relative to a two-choice response task. The most prevalent response strategy during the two-choice prediction task was "win-stay/lose-shift," where subjects will repeat the previous response if it successfully predicted the stimulus and switch to the alternative response otherwise. Increased frequency of responses that are consistent with this strategy is associated with activation in the superior temporal gyrus. In comparison, increased frequency of response inconsistent with win-stay/lose-shift is associated with parietal cortex activation. These results support the hypothesis that subjects use a frontoparietal neural system to establish a contingency based decision-making strategy even in the presence of random reinforcement.

Plant biotechnology. Italian scientists blast GMO restrictions

While plant scientists around the world celebrate the complete sequence of the genome of the mustardlike plant Arabidopsis thaliana (see p. 2054), embattled colleagues in Italy are protesting new rules that bar all field trials involving genetically modified organisms (GMOs). The researchers hope to turn the prevailing tide by bringing their plight to the attention of colleagues around the world and exerting pressure on their government through a petition drive.

Molecular biology. EMBL rescued from the financial brink

Scientists at the European Molecular Biology Laboratory were breathing a sigh of relief last week after the topflight center in Heidelberg, Germany, announced a 25% budget increase for the next 5 years. The boost eases months of uncertainty over how the lab would comply with an order to pay employees back salary and provides a measure of stability to its renowned but embattled European Bioinformatics Institute.

Intertarsal ligaments: high resolution MRI and anatomic correlation

High resolution MRI was performed on four cadaveric foot specimens of human feet to demonstrate the ligaments of the tarsal joints. Spin echo T1 images were obtained using a local gradient coil that produces 6 G/cm and 100 A in all three axes. The best views for each of the individual ligaments were determined. High resolution MRI potentially can demonstrate most of the intertarsal ligaments.

Zinc-responsive dermatosis in a red wolf (canis rufus)

An 18-mo-old male red wolf (Canis rufus) presented with footpad hyperkeratosis, suppurative paronychia, distal limb pyoderma, and peripheral lymphadenopathy. Diet for the previous 11 mo consisted of a mixture of two commercially prepared dog foods with a mineral supplement containing primarily calcium. Culture of the draining tracts on the distal limbs yielded a mixed population of opportunistic bacteria. Histopathologic findings were consistent with a diagnosis of zinc deficiency. Medical therapy consisted of 15 mg/kg amoxicillin p.o. b.i.d. and 10 mg/kg zinc sulfate p.o. s.i.d. Calcium supplementation was discontinued. Clinical signs resolved by 10 wk after the initiation of treatment.

Upper gastrointestinal symptoms in North America: prevalence and relationship to healthcare utilization and quality of life

The aim of this study was to determine the prevalence of upper gastrointestinal symptoms (UGIS) in a general population and quantify the relationship of those symptoms to healthcare utilization and quality of life. In-person interviews were conducted with 2056 United States and Canadian residents selected at random. Subjects reported frequency and severity for 11 symptoms, prescription and over-the-counter medication use, primary care and specialty physician visits in prior three months, and completed the Psychological General Well-Being Scale. For analyses, subjects were classified into four mutually exclusive symptom groups: gastroesophageal reflux disease (GERD) -like, GERD plus motility-like (GERD+), ulcerlike, and motility-like. Of the total sample, 51.4% reported the occurrence of at least one UGIS in the prior three months. Subjects in the GERD+ and ulcer groups used more prescription medications and were more likely to see a physician about the symptoms (P<0.001). Subjects with symptoms demonstrated poorer quality of life compared to subjects with no symptoms. The prevalence of UGIS in the general population is high and symptoms are associated with significant health-care utilization and poorer quality of life.

A novel in-lens detector for electrostatic scanning LEEM mini-column

A novel principle of an in-lens detector of very slow electrons is described and the detector efficiency discussed. The detector was built into a coaxial column for a Cylindrical Mirror Analyser for Auger electron microanalysis. In order to obtain a very low energy scanned imaging, a cathode lens was formed between the final electrode of the column and a negatively biased specimen. The signal electrons accelerated within the cathode lens field enter the column and after being mirrored back impact a micro-channel-plate based detector fitted around the optical axis. The acceptance of the detector, expressed as a ratio of the number of electrons impacting the detector to the full emission of a cosine source, was calculated to be 0.86 for 1 eV and 0.985 for 10 eV electrons. Then, the efficiency of conversion into output pulses is 0.35 and 0.31, respectively; these parameters are superior to those of conventional SEM detectors for secondary electrons. Micrographs taken at low energies ranging down to units of eV are presented.

Prisons and public health: emerging issues in HIV treatment adherence

Correctional facilities in the United States are faced with challenges in providing appropriate and timely HIV treatment to incarcerated HIV-infected inmates. Prison and jails, due to their structure, operation, and staff, may present many barriers to HIV treatment and adherence to complicated and expensive HIV treatment regimens. Changes and modifications of prison health care delivery are required to accommodate the needs of HIV-infected inmates. Approaches to improving correctional HIV care and treatment include training health care personnel, prevention education for inmates, increasing access to voluntary HIV testing, comprehensive treatment planning, and continuity of care. Policy changes for correctional systems include adopting current HIV care standards and immediate evaluation for and access to HIV treatment upon entry into the institution. These changes can have a significant impact on the quality of care for inmates, ultimately improving their quality of life and reducing the morbidity and mortality of HIV disease for incarcerated populations.

Psychometric validation of a constipation symptom assessment questionnaire

BACKGROUND

Clinical management of constipation is complicated by the lack of a gold standard for evaluation of symptoms. A constipation symptom assessment instrument, the PAC-SYM, was developed to address the patient perspective on the disorder. Instrument content was based on literature review and results of focus groups.

METHODS

Two hundred and sixteen patients at nine sites participated in a 6-week psychometric evaluation of the PAC-SYM. The final instrument contained 12 items assigned to 3 subscales: stool symptoms, rectal symptoms, and abdominal symptoms. The psychometric properties of this final instrument were assessed.

RESULTS

Internal consistency and test-retest reliability of the final instrument was high (Cronbach's alpha = 0.89; intraclass correlation = 0.75). Concurrent validity was supported by the correlation with both subject and investigator constipation severity ratings (r= 0.68 and 0.72, respectively; P < 0.0001). Scores were moderately correlated with instruments measuring quality of life. Comparison of treatment responders with nonresponders showed the ability of the instrument to differentiate between groups on the basis of clinical severity (t = -6.12, P < 0.0001 ). Scores changed significantly over time among responders, indicating instrument responsiveness.

CONCLUSIONS

The PAC-SYM is internally consistent, reproducible under stable conditions, valid, and responsive to change and provides a comprehensive means to assess the effectiveness of treatment for constipation.

Pharmacoeconomic evaluation in the real world. Effectiveness versus efficacy studies

Pharmacoeconomic data may be obtained within the context of randomised clinical trials (RCTs) and from effectiveness studies in the 'real world'. The differences between the 2 types of study design have implications for the types of data that can be obtained and the interpretation of the resulting findings. Because RCTs are designed to assess the safety and efficacy of pharmaceuticals, and because the study design of RCTs emphasises internal validity over generalisability, the pharmacoeconomic data collected from them are limited. The data may not be applicable to the more heterogeneous patients encountered in actual clinical practice, and cost estimates may be inaccurate because of protocol requirements. Effectiveness studies, in which treatments are studied under real-world conditions, remedy some of these limitations. Generalisability to actual users is generally enhanced in effectiveness designs, but data may be biased in other ways. This brief review compares the 2 study designs as they relate to pharmacoeconomic evaluations in terms of the research questions they address, design differences and their implications for study bias, data collection and data analysis and the generalisability of their results.

Exposure to peanuts in utero and in infancy and the development of sensitization to peanut allergens in young children

This study attempted to determine the underlying factors that may influence the development of peanut sensitization in young children in South Africa. One of our objectives was to ascertain whether the consumption of peanuts or peanut-containing foods during pregnancy and lactation by mothers from atopic families impacted upon the development of an allergic response to peanuts in the child. Forty-three children between the ages of 0 and 3 yr participated in this study. There were 25 peanut-sensitized subjects and 18 control subjects (children sensitized to milk and/or egg, but not to peanuts). A significant association was found between peanut sensitization and sensitivity to soya (p=0.0002), wheat (p=0.03), and cod fish. We found that mothers who consumed peanuts more than once a week during pregnancy were more likely to have a peanut-allergic child than mothers who consumed peanuts less than once a week (odds ratio=3.97, 98% confidence interval 0.73-24). Peanuts or peanut butter was introduced into the child's diet from a significantly younger age in the peanut-allergic subjects (p<0.03). There was a positive correlation in the peanut-allergic subjects between age of introduction of peanuts and age at the onset of symptoms (r=0.63). Exclusive breast feeding did not protect against the development of peanut sensitization. Peanut allergy is associated with an increased risk of sensitization to other foods. It is more likely to occur if mothers eat peanuts more frequently during pregnancy and introduce it early to the infant's diet. These features highlight potentially avoidable factors that might prevent sensitization.

Magnetic resonance imaging of knee cartilage repair

Cartilage injury resulting in osteoarthritis is a frequent cause of disability in young people. Osteoarthritis, based on either cartilage injury or degeneration, is a leading cause of disability in the United States. Over the last several decades, much progress has been made in understanding cartilage injury and repair. Magnetic resonance (MR) imaging, with its unique ability to noninvasively image and characterize soft tissue, has shown promise in assessment of cartilage integrity. In addition to standard MR imaging methods, MR imaging contrast mechanisms under development may reveal detailed information regarding the physiology and morphology of cartilage. MR imaging will play a crucial role in assessing the success or failure of therapies for cartilage injury and degeneration.

Correlates of disruptive behavior in severely cognitively impaired nursing home residents

This article provides information about correlates of "disruptive behaviors" among nursing home residents with dementia. We used averages of multiple observations for a wide range of behaviors (n = 45) across 11 months to gather this information. We placed behaviors into four separate categories: physically aggressive, physically non-aggressive, vocally agitated, and vocally aggressive. Then, we tested associations between these categories and demographic, cognitive, and health variables. Cognitive status and selected demographic variables were associated with the behavior categories; adding health variables did not improve prediction. Lower cognitive status was associated with more disruptive behaviors. Our findings suggest that cognitive status, but not health variables, predicts disruptive behavior among nursing home residents with dementia.

Hemispheric asymmetries in global and local processing: evidence from fMRI

Functional magnetic resonance imaging (fMRI) was used to explore the brain substrate associated with global and local processing of visuospatial patterns. Systematic differences in activation, consistent with differences observed in reaction time data collected under conditions of visual hemifield presentation, were found in occipitotemporal regions of the right and left hemispheres. Within the right hemisphere, area of activation and fractional signal changes were greater under conditions of global processing than under local processing conditions. In the left hemisphere, activation to global and local input was high and comparable.

Effects of BDNF infusion on the regulation of TrkB protein and message in adult rat brain

Exposure of embryonic CNS neurons to BDNF in vitro causes down-regulation of TrkB protein and mRNA, and an attenuation of functional responses to acute neurotrophin stimulation. In order to investigate ligand-mediated regulation of TrkB in vivo, we infused BDNF into the midbrain, near the periaquaductal grey-dorsal raphe (PAG-DR), or into the olfactory bulb of adult rats. Midbrain infusion of BDNF produced analgesia that was sustained for the duration of BDNF delivery. Analysis of TrkB receptor levels revealed that at the point when the maximal analgesic effect of BDNF was obtained, there was a concommitant 75% decrease in full-length TrkB protein at the infusion site. After discontinuation of infusion, levels of TrkB recovered toward base line. Interestingly, TrkB protein levels were not accompanied by decreased trkB mRNA levels. To determine if BDNF infusion decreased TrkB protein levels in other brain areas and whether trkB mRNA might be down-regulated in the cell bodies of neurons projecting to the infusion site, we infused BDNF into the olfactory bulb. Following a 12-day infusion of BDNF, TrkB protein levels decreased within the bulb to a similar extent as in the PAG-DR. This decrease in receptor protein, however, was not accompanied by decreased trkB mRNA levels in the olfactory cortex, which is afferent to the bulb. Taken together, our data suggest that decreases in TrkB receptor protein at the site of BDNF infusions in the adult brain represent receptor turnover, but this is not associated with altered expression of trkB mRNA or attenuation of the pharmacological effects of BDNF.