Influence of Viral Infections on Body Weight, Survival, and Tumor Prevalence of B6C3F1 (C57BL/6N ? C3H/HeN) Mice in Carcinogenicity Studies

Sendai virus (SV), mouse hepatitis virus (MHV), and pneumoniavirus of mice (PVM) are common viral infections of mice. Influenceof these viral infections on the prevalence of liver tumors,lung tumors, and lymphoma is of concern in chemical carcinogenicitystudies. Body weight, survival, and tumor prevalence of B6C3F1mice with and without viral infections in 33 male and 34 femaleuntreated control groups and 32 male and 32 female low- andhigh-dose groups of 2-year chemical carcinogenicity studieswere evaluated. In male mice, the SV infection was associatedwith significantly (p < 0.05) higher survival of control,low-dose, and high-dose groups, and higher prevalence of livertumors and lymphoma. The increases in tumor prevalence are possiblydue to an increase in the survival of male mice that had SVinfection. However, when interlaboratory variability and time-relatedeffects were taken into account, the number of significant effectswas consistent with the expected false-positive rate inherentto the statistical procedures. The MHV and PVM infections didnot cause consistent changes in body weight, survival, and tumorprevalences in the control and chemical treatment groups ofmale mice. Viral infections did not cause consistent increasesor decreases in body weight, survival, or tumor prevalence inthe control and chemical treatment groups of female B6C3F1 mice.     

Aldicarb Immunotoxicity: Functional Analysis of Cell-Mediated Immunity and Quantitation of Lymphocyte Subpopulations

Aldicarb Immunotoxicity: Functional Analysis of Cell-MediatedImmunity and Quantitation of Lymphocyte Subpopulations. THOMAS,P., RATAJCZAK, H., DEMETRAL, D., HAGEN, K., AND BARON, R. (1990).Fundam. Appl. Toxicol. 15, 221–230. Adult female B6C3F1mice received distilled water only or water containing 1.0,10, or 100 ppb of aldicarb daily for 34 days. The target concentrationof aldicarb present in the 100 ppb dosing solution was analyticallyverified. To further develop an immune profile of this compound,following aldicarb exposure, the ability of splenic naturalkiller cells and specifically sensitized cytotoxic T-lymphocytesto lyse YAC-1 lymphoma and P815 tumor cells, respectively, wasevaluated. To supplement the functional assays, the impact ofaldicarb exposure on the percentages and absolute numbers oftotal T-cells, T-suppressor, T-helper, and B-cells was evaluated.The absence of statistically significant effects on any of theseparameters supports earlier reports that aldicarb does not resultin adverse effects on the immune system of mice.     

Chronic Dietary Toxicity/Oncogenicity Studies on 2,4-Dichlorophenoxyacetic Acid in Rodents

Forms of 2,4-dichlorophenoxyacetic acid (collectively knownas 2,4-D) are herbicides used to control a wide variety of broadleafand woody plants. Doses in the 2-year chronic/oncogenicity ratstudy were 0, 5, 75, and 150 mg/kg/day. The chronic toxicityparalleled subchronic findings, and a NOEL of 5 mg/kg/day wasestablished. A slight increase in astrocytomas observed (inmales only) at 45 mg/kg/day in a previously conducted chronicrat study was not confirmed in the present study at the highdose of 150 mg/kg/day. Doses in the 2-year mouse oncogenicitystudies were 0, 5, 150, and 300 mg/kg/day for females and 0,5, 62.5, and 125 mg/kg/day for males. No oncogenic effect wasnoted in the study. In summary, the findings of these studiesindicate low chronic toxicity of 2,4-D and the lack of oncogenicresponse to 2,4-D following chronic dietary exposure of 2,4-Din the rat and mouse.     

THE NATURE OF ARTHRITIS PAIN

A modified version of the McGill Pain Questionnaire in visualanalogue format was used to evaluate the sensory, affectiveand evaluative intensities of pain experienced by 40 patientswith rheumatoid arthritis and 20 patients with degenerativearthritis. The affective component of the pain was found tobe more intense than the sensory component in all patients indicatingthe importance of emotional factors in the pain experience.The sensory aspects of the pain were more complex than the affectiveones reflecting the varied sources and combinations of somaticpathology. There were no significant differences found in theoverall pain experience between rheumatoid and degenerativearthritis. No differences were noted in the evaluative categoryof pain. Overall pain intensity increased with disease durationin both rheumatoid and degenerative arthritis. The relationshipof affective and sensory components of the pain experience didnot alter with duration of disease. KEY WORDS: Arthritis, Pain     

Haemostasis and Thrombosis: Current Clinical Practice: Low-Molecular-Weight Heparins in The Prophylaxis and Treatment of Thrombo-Embolic Disease

Low-Molecular-Weight Heparin (LMWH) fractions are prepared from standard unfractionated heparin (UFH) and are thus similar to it in many aspects. The major advantages of LMWH are improved efficacy and safety, longer half-life and reduced need for laboratory monitoring. In addition, the dangers of UFH administered by continuous infusion in the hospital setting are often not fully appreciated and the necessary monitoring and dosage adjustment poorly carried out resulting in inadequate doses being given. LMWHs are the drug of choice in many clinical situations. Four LMWHs are now licensed in the UK for prophylaxis of venous thrombo-embolism during or after surgery (Certoparin, Dalteparin [Fragmin], Enoxaparin [Lovenox/Clexane] and Tinzaparin [Innohep]; a fifth is licensed but not currently available in the UK. Dalteparin, Enoxaparin and Tinzaparin are licensed for the treatment of Deep Vein Thrombosis (DVT), and Tinzaparin additionally for the treatment of Pulmonary Embolism (PE), but so far none is licensed for use in pregnancy or paediatrics.     

An in vivo investigation of salivary properties,enamel hypomineralisation,and carious lesion severity in a group of Iraqi schoolchildren

International Journal of Paediatric Dentistry 2013; 23: 2–12 Background. Hypomineralised enamel is a prevalent, congenital defect vulnerable to deteriorate post‐eruptively particularly in the presence of an unfavourable oral environment. Aims. To assess the influence of salivary characteristics on the clinical presentation of hypomineralisation lesions diagnosed in first permanent and second primary molars and to evaluate caries severity in relation to the defect’s clinical presentation. Design. Recruitment consisted of 445 seven‐ to nine‐year‐old participants, of whom 152 were diagnosed as having molar hypomineralisation (MH); the remaining unaffected subjects (N = 293) were considered their controls for saliva analysis. Dental caries status was assessed in 300 subjects of saliva sub‐sample, equally divided as MH‐affected and non‐affected children. The International Caries Detection and Assessment System was used for caries detection. Salivary flow rates, viscosity, pH, and buffering capacity were determined. Results. Molar hypomineralisation‐affected children have significantly higher mean caries scores compared to the non‐affected group. Dentinal carious lesions were ten times more frequent in teeth with post‐eruptive breakdown (PEB) than with teeth with opacities only. Low salivary flow rates (LSFR), moderately viscous saliva, and low pH were significantly more common in the affected group. LSFR and moderate and highly acidic saliva were more likely associated with PEB. Conclusion. Demarcated hypomineralised enamel is a dynamic defect highly influenced by individual characteristics of the oral environment.