ABSTRACT
Human neuroimaging studies and complementary animal experiments now identify the gross elements of the brain involved in the chronification of pain. We briefly review these advances in relation to somatic and orofacial persistent pain conditions. First, we emphasize the importance of reverse translational research for understanding chronic pain-that is, the power of deriving hypotheses directly from human brain imaging of clinical conditions that can be invasively and mechanistically studied in animal models. We then review recent findings demonstrating the importance of the emotional brain (i.e., the corticolimbic system) in the modulation of acute pain and in the prediction and amplification of chronic pain, contrasting this evidence with recent findings regarding the role of central sensitization in pain chronification, especially for orofacial pain. We next elaborate on the corticolimbic circuitry and underlying mechanisms that determine the transition to chronic pain. Given this knowledge, we advance a new mechanistic definition of chronic pain and discuss the clinical implications of this new definition as well as novel therapeutic potentials suggested by these advances.
Subject(s)
Brain/diagnostic imaging , Brain/physiopathology , Chronic Pain/physiopathology , Chronic Pain/psychology , Emotions , Facial Pain/physiopathology , Facial Pain/psychology , Limbic System/physiopathology , Neuroimaging , Animals , Humans , Pain Management , Pain MeasurementABSTRACT
UNLABELLED: Fracture history is an important component of osteoporosis diagnosis in children. One in six parentally reported lifetime fractures in children were not confirmed on review of radiographs. Care should be taken to avoid unnecessary investigations for possible osteoporosis due to parental over-reporting of soft tissue injuries as fractures. INTRODUCTION: The diagnosis of osteoporosis in children requires either a vertebral compression fracture, or a significant fracture history (defined as ≥2 long bone fractures <10 years or ≥3 long bone fractures <19 years, excluding high impact fractures) and low bone mineral density. As children with frequent fractures might benefit from further evaluation, we determined whether parental reports of lifetime fracture were accurate compared to radiological reports and if they appropriately selected children for further consideration of osteoporosis. METHODS: Parents of children (<18 years) with a musculoskeletal injury completed a questionnaire on their child's fracture history, including age, site and mechanism of previous fracture(s). Radiological reports were reviewed to confirm the fracture. RESULTS: Six hundred sixty parents completed the questionnaire and reported 276 previous fractures in 207 children. An injury treated at our hospital was recorded in 214 of the 276 parentally reported fractures. Thirty-four of 214 (16 %) were not a confirmed fracture. An injury was recorded for all parentally reported fractures in 150 children, but for 21 % children, there were inaccurate details (no evidence of fracture, incorrect site or forgotten fractures) on parent report. Eighteen of 150 children had a significant fracture history on parental report alone, but following review of radiology reports, 2 of 18 (11 %) did not have clinically significant fracture histories. CONCLUSIONS: Approximately one in six fractures reported by parents to have occurred in their child's lifetime had not resulted in a fracture. One in nine children with a significant fracture history could have been investigated unnecessarily.
Subject(s)
Medical History Taking/standards , Mental Recall , Osteoporosis/diagnosis , Osteoporotic Fractures/diagnosis , Parents/psychology , Adolescent , Child , Child, Preschool , England , Female , Humans , Infant , Male , Osteoporotic Fractures/psychology , Patient Selection , Recurrence , Unnecessary Procedures/statistics & numerical dataABSTRACT
Based on theoretical considerations and recent observations, we argue that continued suffering of chronic pain is critically dependent on the state of motivational and emotional mesolimbic-prefrontal circuitry of the brain. The plastic changes that occur within this circuitry in relation to nociceptive inputs dictate the transition to chronic pain, rendering the pain less somatic and more affective in nature. This theoretical construct is a strong departure from the traditional scientific view of pain, which has focused on encoding and representation of nociceptive signals. We argue that the definition of chronic pain can be recast, within the associative learning and valuation concept, as an inability to extinguish the associated memory trace, implying that supraspinal/cortical manipulations may be a more fruitful venue for adequately modulating suffering and related behavior for chronic pain. We briefly review the evidence generated to date for the proposed model and emphasize that the details of underlying mechanisms remain to be expounded.
Subject(s)
Brain/physiopathology , Chronic Pain/pathology , Chronic Pain/physiopathology , Learning Disabilities/etiology , Neuronal Plasticity/physiology , HumansABSTRACT
BACKGROUND: The diversity of quality improvement interventions (QIIs) has impeded the use of evidence review to advance quality improvement activities. An agreed-upon framework for identifying QII articles would facilitate evidence review and consensus around best practices. AIM: To adapt and test evidence review methods for identifying empirical QII evaluations that would be suitable for assessing QII effectiveness, impact or success. DESIGN: Literature search with measurement of multilevel inter-rater agreement and review of disagreement. METHODS: Ten journals (2005-2007) were searched electronically and the output was screened based on title and abstract. Three pairs of reviewers then independently rated 22 articles, randomly selected from the screened list. Kappa statistics and percentage agreement were assessed. 12 stakeholders in quality improvement, including QII experts and journal editors, rated and discussed publications about which reviewers disagreed. RESULTS: The level of agreement among reviewers for identifying empirical evaluations of QII development, implementation or results was 73% (with a paradoxically low kappa of 0.041). Discussion by raters and stakeholders regarding how to improve agreement focused on three controversial article selection issues: no data on patient health, provider behaviour or process of care outcomes; no evidence for adaptation of an intervention to a local context; and a design using only observational methods, as correlational analyses, with no comparison group. CONCLUSION: The level of reviewer agreement was only moderate. Reliable identification of relevant articles is an initial step in assessing published evidence. Advancement in quality improvement will depend on the theory- and consensus-based development and testing of a generalizable framework for identifying QII evaluations.
Subject(s)
Bibliometrics , Comparative Effectiveness Research , Evaluation Studies as Topic , Quality Improvement/trends , Consensus , Evidence-Based Medicine , Humans , Observer Variation , Periodicals as Topic , Publishing/trends , United StatesABSTRACT
Mucosa-associated lymphoid tissue (MALT) is a type of extra nodal malignant lymphoma seen in organs such as the stomach, thyroid and salivary glands. Furthermore, occurrence of colorectal MALT lymphoma is extremely rare. We report a case of a solitary rectal MALT lymphoma treated by surgical resection and radiotherapy. Lymphoma should be considered as a rare differential diagnosis when dealing with large bowel pathology. We would advocate the use of surgery as a primary treatment option for a medically fit patient.
Subject(s)
Lymphoma, B-Cell, Marginal Zone/pathology , Lymphoma, B-Cell, Marginal Zone/therapy , Rectal Neoplasms/pathology , Rectal Neoplasms/therapy , Aged , Biopsy, Needle , Colectomy/methods , Female , Follow-Up Studies , Humans , Immunohistochemistry , Intestinal Mucosa/pathology , Lymphoma, B-Cell, Marginal Zone/diagnosis , Magnetic Resonance Imaging/methods , Proctoscopy/methods , Radiotherapy, Adjuvant , Rare Diseases , Rectal Neoplasms/diagnosis , Risk Assessment , Treatment OutcomeABSTRACT
The selective EGFR tyrosine kinase inhibitor, gefitinib has been shown to be active against certain human carcinomas. It had been noted that a proportion of volunteers consistently had lower gefitinib exposure following oral administration. The shape of the elimination profile in this subset was also different, showing a monophasic elimination pattern rather than the biphasic pattern observed in the majority of subjects. A gamma scintigraphic study was conducted to examine the relationship of gastrointestinal transit and drug absorption in a cohort of rapid clearance subjects (n=5) and normal profile volunteers (n=7). The fasted volunteer panel received a 250 mg gefitinib tablet labelled with [(111)In]-DTPA together with 240 mL [(99m)Tc]-labelled water. The rapid clearance cohorts were shown to have a faster mean gastric emptying T90 (37 min vs 74 min) and shorter small intestinal transit time (156 min vs 204 min), resulting in an earlier colonic arrival time (181 min vs 244 min). Mean plasma C(max) was lower (99.2 ng/mL vs 116 ng/mL) and AUC almost half in the rapid clearance group (2162+/-81 ngh/mL vs 4996+/-64 ngh/mL). These data suggest that gastrointestinal transit parameters play a role in the differences in the rapid clearance profile group, also contributing to the biphasic to monophasic switch. However, historical data show, at the recommended dose of 250 mg/day steady-state plasma concentrations adequate for clinical benefit are achieved in patients with non-small cell lung cancer.
Subject(s)
ErbB Receptors/antagonists & inhibitors , Gastrointestinal Tract/metabolism , Gastrointestinal Tract/physiology , Protein Kinase Inhibitors/pharmacokinetics , Quinazolines/pharmacokinetics , Adult , Antineoplastic Agents/pharmacokinetics , Drug Compounding , Gastrointestinal Tract/diagnostic imaging , Gefitinib , Humans , Male , Middle Aged , Radioisotopes/metabolism , Radionuclide ImagingABSTRACT
BACKGROUND: Stakeholders in quality improvement agree on the need for augmenting and synthesising the scientific literature supporting it. The diversity of perspectives, approaches, and contexts critical to advancing quality improvement science, however, creates challenges. The paper explores the heterogeneity in clinical quality improvement intervention (QII) publications. METHODS: A preliminary classification framework was developed for QII articles, aiming for categories homogeneous enough to support coherent scientific discussion on QII reporting standards and facilitate systematic review. QII experts were asked to identify articles important to QII science. The framework was tested and revised by applying it to the article set. The final framework screened articles into (1) empirical literature on development and testing of QIIs; (2) QII stories, theories, and frameworks; (3) QII literature syntheses and meta-analyses; or (4) development and testing of QII-related tools. To achieve homogeneity, category (1) required division into (1a) development of QIIs; 1(b) history, documentation, or description of QIIs; or (1c) success, effectiveness or impact of QIIs. RESULTS: By discussing unique issues and established standards relevant to each category, QII stakeholders can advance QII practice and science, including the scope and conduct of systematic literature reviews.
Subject(s)
Publications/standards , Quality Assurance, Health CareABSTRACT
Non-typeable Haemophilus influenzae (NTHi) is a major cause of respiratory but rarely systemic infection. The host defence to this bacterium has not been well defined in patients with chronic airway infection. The aim of this study was to assess the effect of humoral immunity in host defence to NTHi. Responses were measured in control and bronchiectasis subjects who had recurrent bronchial infection. Antibody and complement-mediated killing was assessed by incubating NTHi with serum and the role of the membrane-attack complex and classical/alternate pathways of complement activation measured. The effect of one strain to induce protective immunity against other strains was assessed. The effect of antibody on granulocyte intracellular killing of NTHi was also measured. The results showed that both healthy control subjects and bronchiectasis patients all had detectable antibody to NTHi of similar titre. Both groups demonstrated effective antibody/complement-mediated killing of different strains of NTHi. This killing was mediated through the membrane-attack complex and the classical pathway of complement activation. Immunization of rabbits with one strain of NTHi resulted in protection from other strains in vitro. Antibody activated granulocytes to kill intracellular bacteria. These findings may explain why NTHi rarely causes systemic disease in patients with chronic respiratory mucosal infection and emphasize the potential importance of cellular immunity against this bacterium.
Subject(s)
Antibodies, Bacterial/immunology , Bronchiectasis/immunology , Haemophilus Infections/immunology , Haemophilus influenzae/immunology , Adult , Aged , Animals , Antibodies, Bacterial/pharmacology , Case-Control Studies , Granulocytes/immunology , Haemophilus influenzae/drug effects , Humans , Immunoglobulin M/immunology , Middle Aged , RabbitsABSTRACT
This trial evaluated the effects of 16 weeks of consumption of 1000mg rebaudioside A (n=60) a steviol glycoside with potential use as a sweetener, compared to placebo (n=62) in men and women (33-75 years of age) with type 2 diabetes mellitus. Mean+/-standard error changes in glycosylated hemoglobin levels did not differ significantly between the rebaudioside A (0.11+/-0.06%) and placebo (0.09+/-0.05%; p=0.355) groups. Changes from baseline for rebaudioside A and placebo, respectively, in fasting glucose (7.5+/-3.7mg/dL and 11.2+/-4.5mg/dL), insulin (1.0+/-0.64microU/mL and 3.3+/-1.5microU/mL), and C-peptide (0.13+/-0.09ng/mL and 0.42+/-0.14ng/mL) did not differ significantly (p>0.05 for all). Assessments of changes in blood pressure, body weight, and fasting lipids indicated no differences by treatment. Rebaudioside A was well-tolerated, and records of hypoglycemic episodes showed no excess vs. placebo. These results suggest that chronic use of 1000mg rebaudioside A does not alter glucose homeostasis or blood pressure in individuals with type 2 diabetes mellitus.
Subject(s)
Diabetes Mellitus, Type 2/blood , Diterpenes, Kaurane/administration & dosage , Sweetening Agents/administration & dosage , Adult , Aged , Blood Glucose/analysis , Blood Pressure/drug effects , C-Peptide/blood , Diterpenes, Kaurane/adverse effects , Double-Blind Method , Fasting , Female , Glycated Hemoglobin/analysis , Humans , Hypoglycemia/epidemiology , Lipids/blood , Male , Middle Aged , Placebos , Sweetening Agents/adverse effectsABSTRACT
Rebaudioside A and stevioside are steviol glycosides extracted from the plant Stevia rebaudiana Bertoni and are used in several countries as food and beverage sweeteners. This randomized, double-blind trial evaluated the hemodynamic effects of 4weeks consumption of 1000mg/day rebaudioside A vs. placebo in 100 individuals with normal and low-normal systolic blood pressure (SBP) and diastolic blood pressure (DBP). Subjects were predominantly female (76%, rebaudioside A and 82%, placebo) with a mean age of approximately 41 (range 18-73) years. At baseline, mean resting, seated SBP/DBP was 110.0/70.3mmHg and 110.7/71.2mmHg for the rebaudioside A and placebo groups, respectively. Compared with placebo, rebaudioside A did not significantly alter resting, seated SBP, DBP, mean arterial pressure (MAP), heart rate (HR) or 24-h ambulatory blood pressures responses. These results indicate that consumption of as much as 1000mg/day of rebaudioside A produced no clinically important changes in blood pressure in healthy adults with normal and low-normal blood pressure.
Subject(s)
Blood Pressure/drug effects , Diterpenes, Kaurane/adverse effects , Hemodynamics/drug effects , Sweetening Agents/adverse effects , Adolescent , Adult , Aged , Blood Pressure Monitoring, Ambulatory , Body Weight , Diet , Diterpenes, Kaurane/administration & dosage , Double-Blind Method , Exercise , Female , Heart Rate/drug effects , Humans , Male , Middle Aged , Placebos , Posture , Sweetening Agents/administration & dosageABSTRACT
Cytotoxic T lymphocytes (CTL) and natural killer (NK) cells have a key role in host defence against infectious pathogens, but their response to bacteria is not well characterized. Non-typeable Haemophilus influenzae is a major cause of respiratory tract infection including otitis media, sinusitis, tonsillitis and chronic bronchitis (especially in chronic obstructive pulmonary disease and bronchiectasis). This bacterium is also present in the pharynx of most healthy adults. The primary factor that may determine whether clinical disease occurs or not is the nature of the lymphocyte response. Here we examined the CTL cell and NK cell responses to nontypeable H. influenzae in healthy control subjects and in subjects who had bronchiectasis and recurrent bronchial infection with this bacterium. Cells were stimulated with live H. influenzae and intracellular cytokine production and release of cytotoxic granules measured. Control subjects had significantly higher levels of interferon gamma production by both CTL and NK cells, while levels of cytotoxic granule release were similar in both groups. The main lymphocyte subsets that proliferated in response to H. influenzae stimulation were the CTL and NK cells. The results suggest that CTL and NK cell responses may be important in preventing disease from nontypeable H. influenzae infection.
Subject(s)
Haemophilus Infections/immunology , Haemophilus influenzae/immunology , Killer Cells, Natural/immunology , T-Lymphocytes, Cytotoxic/immunology , Adult , Aged , Antigens, Bacterial/immunology , Bronchiectasis/immunology , CD56 Antigen/analysis , Cell Proliferation , Cells, Cultured , Cytokines/biosynthesis , Cytotoxicity, Immunologic , Haemophilus influenzae/classification , Histocompatibility Antigens Class I/immunology , Humans , Lymphocyte Activation/immunology , Lymphocyte Subsets/immunology , Lysosomal-Associated Membrane Protein 1/metabolism , Middle Aged , Recurrence , Respiratory Tract Infections/immunologyABSTRACT
BACKGROUND: Accurate digital rectal examination (DRE) enables the early diagnosis of palpable rectal tumour. We aimed at evaluating the diagnostic value of DRE performed by general practitioners (GPs), with respect to detecting the presence of a palpable rectal tumour. METHOD: All patients diagnosed to have a palpable rectal tumour via a 14-day cancer referral system between May and December 2006 were identified from the colorectal database. Patients referred by GPs during the same period as having a palpable rectal tumour were also identified by reviewing the 14-day cancer referrals. Sensitivity, specificity, positive and negative predictive value of a DRE in primary care were calculated by using these data. RESULTS: Between May and December 2006, 1069 patients were referred to the University Hospital of North Staffordshire to the 14-day urgent colorectal cancer referral service. Of these, 108 patients were referred as having a 'palpable rectal tumour'. Only 32 of the 108 were found to have a rectal lesion on examination in the hospital. Ten tumours were missed by GPs' DREs. CONCLUSION: Digital rectal examination in primary care for palpable rectal tumour has a sensitivity of 0.762, specificity of 0.917, positive predictive value of 0.296 and negative predictive value of 0.988. It is an inaccurate procedure and a poor predictor for palpable rectal tumour.
Subject(s)
Digital Rectal Examination/methods , Primary Health Care/methods , Rectal Neoplasms/diagnosis , Referral and Consultation/statistics & numerical data , Colonoscopy/methods , Colonoscopy/statistics & numerical data , Female , Humans , Incidence , Male , Predictive Value of Tests , Probability , Rectal Neoplasms/epidemiology , Registries , Risk Assessment , Sensitivity and Specificity , United Kingdom , Waiting ListsABSTRACT
ABSTRACT Pythium oligandrum is known to display antagonistic activities against several species of pathogenic fungi. It also produces an elicitor of plant defense named oligandrin, which belongs to the elicitin family (10-kDa proteins synthesized by Phytophthora and Pythium species). Here, the potential of P. oligandrum or its purified elicitin to limit the progression of B. cinerea on grapevine leaf and the resulting plant-microorganism interactions are described. P. oligandrum or oligandrin were applied to roots, and changes in the ultrastructure and at the molecular level were examined. When B. cinerea was applied to leaves of pretreated plants, leaf invasion was limited and the protection level reached about 75%. On leaf tissues surrounding B. cinerea inoculation, modifications of cuticle thickness, accumulation of phenolic compounds, and cell wall apposition were observed, indicating that grapevine can be considered reactive to elicitins. No macroscopic hypersensitive reaction associated with the elicitation treatment was observed. At the molecular level, the expression of three defense-related genes (LTP-1, beta-1,3-glucanase, and stilbene synthase) was studied. RNAs isolated from B. cinerea-infected leaves of grapevine challenged or not with P. oligandrum or oligandrin were analyzed by real-time reverse transcription-polymerase chain reaction. In grapevine leaves, LTP-1 gene expression was enhanced in response to oligandrin, and RNA transcript levels of beta-1,3-glucanase and stilbene synthase increased in response to all treatments with different magnitude. Taken together, these results open new discussion on the concept of plant reactivity to elicitins, which has until now, been mainly based on plant hypersensitive responses.
ABSTRACT
Synaptosomes, isolated from the whole brain of young (3 months) and old (24 months) rats were used to study the major bioenergetic systems of neuronal mitochondria in situ, within the synaptosome. Approximately 85% of the resting oxygen consumption of synaptosomes from both young and old rats was a result of proton leak (and possibly other ion cycling) across the mitochondrial inner membrane. There were no significant differences between synaptosomes from the young and old rats in the kinetic responses of the substrate oxidation system, the mitochondrial proton leak and the phosphorylation system to changes in the proton electrochemical gradient. Flux control coefficients of 0.71, 0.27 and 0.02 were calculated for substrate oxidation system, phosphorylation system and the proton leak, respectively, at maximal ATP producing capacity in synaptosomes from young animals. The corresponding values calculated for synaptosomes from old animals were 0.53, 0.43 and 0.05. Thus substrate oxidation had greatest control over oxygen consumption at maximal phosphorylating capacity for synaptosomes from whole brain, with proton leak, having little control under maximal ATP producing capacity. The uncoupled rate of oxygen consumption, in the presence of the mitochondrial uncoupler, carbonyl cyanide p-trifluoromethoxyphenylhydrazone (FCCP), was significantly lower (p = 0.0124) in synaptosomes from old rats (6.08 +/- 0.42, n = 11) when compared with those from the young rats (7.87 +/- 0.48, n = 8). Thus, there is an impaired flux through the substrate oxidation system is synaptosomes from old rats, as compared to synaptosomes from the young animals. These in situ results may have important implications for the interpretation of theories that age-dependent impairment of mitochondrial energy production may result in increased susceptibility to neurodegeneration.
Subject(s)
Brain/metabolism , Mitochondria/metabolism , Oxidative Phosphorylation , Synaptosomes/metabolism , Age Factors , Animals , Brain Chemistry , Kinetics , Male , Membrane Potentials/physiology , Mitochondria/chemistry , Oxidation-Reduction , Oxygen Consumption/physiology , Rats , Rats, Wistar , Synaptosomes/chemistryABSTRACT
INTRODUCTION: In this paper we describe a device which allows consistent acetabular cup placement to reduce post-arthroplasty dislocation. PATIENTS AND METHODS: The development of this surgical appliance is traced from the initial concept to the construction of a device suitable for clinical trials. The system of use is explained. The constraints imposed by the working environment and the methods employed to meet the demands imposed by surgical practice are elucidated. A clinical trial is described in which the device was used to assist in siting acetabular cup placement in ten patients. RESULTS: The accuracy of the ten cup placements done using the device was then compared by radiography with the accuracy of placement of 17 acetabular cups performed in the standard manner. Comparison of the results show a positive benefit arising from using the device. CONCLUSIONS: Our initial good results on cup positioning in laboratory studies are maintained in a clinical setting, but further modifications could lend to even better results.
Subject(s)
Arthroplasty, Replacement, Hip/instrumentation , Acetabulum , Arthroplasty, Replacement, Hip/methods , HumansABSTRACT
The Battery for Rapid Evaluation of Cognitive Functions (Batterie Rapide d'Evaluation des Fonctions Cognitives: BREV) is a quick test to screen children with higher-functioning disorders and to define the patterns of their disorders. After standardization tests in 500 normally developing children aged 4 to 8 years, validation consisted of comparative evaluation of the specificity and sensitivity of the BREV with a wide reference battery in 202 children with epilepsy (108 males, 94 females; mean age 6 years 6 months, SD 1 year 8 months). Children were divided into 10 age groups from 4 to 8 years of age and represented eight epileptic syndromes. The reference battery included verbal and non-verbal intelligence assessment using the Wechsler scale, oral language assessment with a French battery for oral language study, drawing with the Rey figure, verbal and visuo-spatial memory with the McCarthy scale subtest and the Rey figure recall, and educational achievement with the Kaufman subtests. Every function evaluated with the BREV was significantly correlated with the reference battery testing a similar function (p=0.01 to 0.001). Specificity and sensitivity of the BREV verbal and non-verbal scores were correlated with those of the Wechsler scale in more than 75% of children. The BREV, therefore, appears to be a reliable test which has been carefully standardized and validated and is valuable in screening for cognitive impairment in children.
Subject(s)
Cognition Disorders/diagnosis , Developmental Disabilities/diagnosis , Epilepsy/complications , Epilepsy/psychology , Mass Screening , Neuropsychological Tests/statistics & numerical data , Child , Child, Preschool , Female , Humans , Intelligence Tests , Language , Male , Memory , Neuropsychological Tests/standards , Reference Values , Sensitivity and SpecificityABSTRACT
Colitic lesions are much more severe in C3H/HeJBir (C3H) than C57BL/6J (B6) mice after 10 backcrosses of a disrupted interleukin-10 (Il10) gene. This study identified cytokine deficiency-induced colitis susceptibility (Cdcs) modifiers by using quantitative trait locus (QTL) analysis. A segregating F(2) population (n = 408) of IL-10-deficient mice was genotyped and necropsied at 6 weeks of age. A major C3H-derived colitogenic QTL (Cdcs1) on chromosome (Chr.) 3 contributed to lesions in both cecum [logarithm of odds ratio (LOD) = 14.6)] and colon (LOD = 26.5) as well as colitis-related phenotypes such as spleen/body weight ratio, mesenteric lymph node/body weight ratio, and secretory IgA levels. Evidence for other C3H QTL on Chr. 1 (Cdcs2) and Chr. 2 (Cdcs3) was obtained. Cdcs1 interacted epistatically or contributed additively with loci on other chromosomes. The resistant B6 background also contributed colitogenic QTL: Cdcs4 (Chr. 8), Cdcs5 (Chr. 17, MHC), and Cdcs6 (Chr. 18). Epistatic interactions between B6 QTL on Chr. 8 and 18 contributing to cecum hyperplasia were particularly striking. In conclusion, a colitogenic susceptibility QTL on Chr. 3 has been shown to exacerbate colitis in combination with modifiers contributed from both parental genomes. The complex nature of interactions among loci in this mouse model system, coupled with separate deleterious contributions from both parental strains, illustrates why detection of human inflammatory bowel disease linkages has proven to be so difficult. A human ortholog of the Chr. 3 QTL, if one exists, would map to Chr. 4q or 1p.
Subject(s)
Colitis/genetics , Interleukin-10/immunology , Quantitative Trait, Heritable , Animals , Chromosomes , Colitis/pathology , Colitis/physiopathology , Epistasis, Genetic , Female , Genetic Linkage , Interleukin-10/genetics , Male , Mice , Mice, Inbred C3H , Mice, Inbred C57BL , Mice, KnockoutABSTRACT
Light and transmission electron microscopy of tissues of the symbiotic clam Corculum cardissa (L) showed that a symbiotic dinoflagellate, Symbiodinium corculorum (Trench), is found predominantly in the mantle and the gills. The data suggest that in C. cardissa the algae are located in a zooxanthellal tubular system that is associated with the hemocoel and is similar to that seen in tridacnine ("giant") clams. The algae occur within the lumen of the tertiary tubules and are thus separated from the hemolymph by a tissue that is one cell layer thick. Under a light microscope the tertiary tubules appear as rows of symbionts originating from the digestive diverticulum, presumably branching from the primary tubules that are also seen in symbiotic tridacnine clams. This morphological arrangement is discussed with regard to the ontogeny and the evolution of the tubular system within symbiotic bivalves.
Subject(s)
Bivalvia/anatomy & histology , Dinoflagellida/physiology , Eukaryota/physiology , Symbiosis/physiology , Animals , Bivalvia/physiology , Bivalvia/ultrastructure , Gills/physiology , Micronesia , Microscopy, ElectronABSTRACT
In the post-genomic era, the laboratory mouse will excel as a premier mammalian system to study normal and disordered biological processes, in part because of low cost, but largely because of the rich opportunities that exist for exploiting genetic tools and technologies in the mouse to systematically determine mammalian gene function. Many robust models of human disease may therefore be developed, and these in turn will provide critical clues to understanding gene function. The full potential of the mouse for understanding many of the neural and behavioral phenotypes of relevance to neuroscientists has yet to be realized. With the full anatomy of the mouse genome at hand, researchers for the first time will be able to move beyond traditional gene-by-gene approaches and take a global view of gene expression patterns crucial for neurobiological processes. In response to an action plan for mouse genomics developed on the basis of recommendations from the scientific community, seven institutes of the National Institutes of Health (NIH) initiated in 1999 a mouse genetics research program that specifically focused on neurobiology and complex behavior. The specific goals of these neuroscience initiatives are to develop high-throughput phenotyping assays and to initiate genome-wide mutagenesis projects to identify hundreds of mutant strains with heritable abnormalities of high relevance to neuroscientists. Assays and mutants generated in these efforts will be made widely available to the scientific community, and such resources will provide neuroscientists unprecedented opportunities to elucidate the molecular mechanisms of neural function and complex behavior. Such research tools ultimately will permit the manipulation and analysis of the mouse genome, as a means of gaining insight into the genetic bases of the mammalian nervous system and its complex disorders.