Hypergammaglobulinemia and autoantibody induction mechanisms in viral infections

Polyclonal hypergammaglobulinemia is a characteristic of chronic inflammatory conditions, including persisting viral infections and autoimmune diseases. Here we have studied hypergammaglobulinemia in mice infected with lymphocytic choriomeningitis virus (LCMV), which induces nonspecific immunoglobulins as a result of switching natural IgM specificities to IgG. The process is dependent on help from CD4+ T cells that specifically recognize LCMV peptides presented by B cells on major histocompatibility complex class II molecules. Thus, hypergammaglobulinemia may arise when specific helper T cells recognize B cells that have processed viral antigens irrespective of the B cell receptor specificity. This nonspecific B cell activation may contribute to antibody-mediated autoimmunity.     

Selection of strains for quality assessment of the disk induction method for detection of inducible clindamycin resistance in Staphylococci: a CLSI collaborative study

A nine-laboratory collaborative study was conducted to select positive and negative quality assessment control strains for the detection of inducible clindamycin resistance in staphylococci. Four strains of Staphylococcus aureus were tested as unknowns on 10 different days in each laboratory using the recently recommended CLSI (formerly NCCLS) disk diffusion method and the inoculum purity control method. Strains contained either macrolide-lincosamide-streptogramin B (MLSB) resistance genes encoded by erm(A) or erm(C) or a macrolide resistance efflux pump encoded by msr(A). Based upon the results of this study, strain UT 32 (now designated ATCC strain BAA-977) containing erm(A) is recommended as the positive control organism for inducible clindamycin resistance. Strain UT 25 (now designated ATCC BAA-976), which harbors the efflux pump encoded by msr(A), is recommended as the negative control organism.     

Human TLR-7-, -8-, and -9-mediated induction of IFN-alpha/beta and -lambda Is IRAK-4 dependent and redundant for protective immunity to viruses

Five TLRs are thought to play an important role in antiviral immunity, sensing viral products and inducing IFN-alpha/beta and -lambda. Surprisingly, patients with a defect of IRAK-4, a critical kinase downstream from TLRs, are resistant to common viruses. We show here that IFN-alpha/beta and -lambda induction via TLR-7, TLR-8, and TLR-9 was abolished in IRAK-4-deficient blood cells. In contrast, IFN-alpha/beta and -lambda were induced normally by TLR-3 and TLR-4 agonists. Moreover, IFN-beta and -lambda were normally induced by TLR-3 agonists and viruses in IRAK-4-deficient fibroblasts. We further show that IFN-alpha/beta and -lambda production in response to 9 of 11 viruses tested was normal or weakly affected in IRAK-4-deficient blood cells. Thus, IRAK-4-deficient patients may control viral infections by TLR-3- and TLR-4-dependent and/or TLR-independent production of IFNs. The TLR-7-, TLR-8-, and TLR-9-dependent induction of IFN-alpha/beta and -lambda is strictly IRAK-4 dependent and paradoxically redundant for protective immunity to most viruses in humans.     

Growth and maturation of cardiac myocytes in fetal sheep in the second half of gestation

Right (RVFW) and left (LVFW) ventricular free wall cardiac myocytes were collected from 25 fetal sheep aged 77-146 days gestation (term = 150 days gestation), six saline-infused catheterized fetal sheep (129 GD), and five lambs to measure gestational changes in uni- and binucleated cardiac myocyte numbers and cell volumes by confocal microscopy. At 77 days gestation, 2% of the myocytes were binucleated, which increased to 50% at 135 days gestation and 90% at 4-6 weeks after birth. RVFW uni- and binucleated myocytes were larger than those in the LVFW, and cell volumes of RVFW uni- and binucleated and LVFW binucleated myocytes (but not LVFW uninucleated myocytes) increased with gestation. Before birth, the approximate number of myocytes was greater in the LVFW than in the RVFW (P < 0.001). Before 110 GD, cardiac growth appeared to be due to myocyte hyperplasia, as approximate myocyte numbers and VFW weight increased at the same rate. After 110 days gestation, the approximate myocyte number/g VFW weight decreased, which suggests that myocyte hypertrophy, as well as hyperplasia, was occurring in association with the appearance of a greater proportion of binucleated cells after that time. By 4-6 weeks of age, there was marked hypertrophy of myocytes and an apparent reduction in myocyte number.     

The matrix metalloproteinase-3 (MMP-3) 5A/6A promoter polymorphism is not associated with ischaemic heart disease: analysis employing a family based approach

Matrix metalloproteinase-3 (MMP-3) has been proposed as an important mediator of the atherosclerotic process. The possible role of the functional -1612 5A/6A polymorphism of the MMP-3 gene in the susceptibility to ischaemic heart disease (IHD) was investigated in a well-defined Irish population using two recently described family based tests of association. One thousand and twelve individuals from 386 families with at least one member prematurely affected with IHD were genotyped. Using the combined transmission disequilibrium test (TDT)/sib-TDT and the pedigree disequilibrium test (PDT), no association between the MMP-3 -1612 5A/6A polymorphism and IHD was found. Our data demonstrate that, in an Irish population, the MMP-3 -1612 5A/6A polymorphism is not associated with IHD.     

Measurement Issues in Emotion Research With Children and Adolescents

The need for a multimethod approach to the study of emotion in children and adolescents is crucial, as is a multilevel analysis in which emotional experience is assessed at a variety of levels (Solomon, 2002). This review highlights the critical role of emotion theory when constructing and selecting appropriate assessment tools with a focus on Functionalist theory that emphasizes the importance of contextual variables ( Barrett & Campos, 1987 ). The review begins with an examination of theoretical and pragmatic issues in emotion measurement followed by discussions of four basic methods of emotion assessment (i.e., self-report, other-report, observation, neurophysiology). Implications of emotion assessment for clinical practice and future directions for research conclude the review.     

Localization of dopamine-1 receptors along the microdissected rat nephron

Dopamine exerts numerous actions on the kidney but the precise location of its receptor subtypes along the nephron is unknown. Using a microassay we determined the specific binding of ¹²⁵I-Sch 23982, a specific and selective dopamine-1 (DA₁) receptor antagonist, to microdissected glomeruli and tubule segments. Binding of ¹²⁵I-Sch 23982 in the proximal convoluted tubule (PCT) was timeand concentration dependent, saturable and reversible. The linear Scatchard plot of saturation experiments suggested binding to a single site with an apparent K _d of 16.7 nM and B _max of 0.4 fmol·mm^–1 in the PCT, and 6.2 nM and 0.1 fmol·mm^–1 in the cortical collecting tubule (CCT). Mapping of DA₁ binding sites along the nephron revealed their presence in each of the segments examined, albeit in markedly different concentrations: the highest specific binding was measured in PCT followed by the pars recta. Binding was less in the distal nephron, and least in the medullary and cortical thick ascending limb. Modest binding was also detected in glomeruli. In cortical collecting tubules competition studies with unlabeled dopamine and probes for DA₁ (Sch 23390, fenoldopam), DA₂ (domperidone, S-sulpiride), serotonergic (serotonin, ketanserin, mianserin), and -(phentolamine) and -(propranolol) adrenergic receptors indicated a rank-order potency for displacement of ¹²⁵I-Sch 23982 binding, consistent with labeling of DA₁ receptors. Dopamine inhibited Na/K-ATPase both in PCT and CCT, an effect duplicated in the latter segment by the DA₁ agonist fenoldopam, and blocked by the DA₁ antagonist Sch 23390. These results demonstrate specific DA₁ binding sites in a nonhomogeneous pattern along the entire nephron, and suggest that dopamine may exert its effect on Na transport in distal as well as in proximal nephron segments.     

Differential assessment of angiogenic activity and of vascular survival ability (VSA) in breast cancer

Recent reports provide evidence that some growth factors behave as inhibitors of the apoptosis of the endothelial cells, bringing forward the concept of vascular survival as a post-angiogenesis process. At least two different vasculature development processes occur within a tumor: the angiogenic (formation of new vessels) and the vascular survival pathway, which is devoted to the preservation of the newly-formed vessels in layers that lose contact with the adjacent normal tissue. We developed a method to assess these processes in tissue samples. We noted that differences among tumors may exist not only in the tumor angiogenic activity (TAA) but also in the vascular survival ability (VSA). One third of the highly angiogenic breast cancer cases examined had a poor ability to maintain high vessel density in inner tumor areas. Both parameters are independently related to prognosis, while VSA was directly related to tumor dimensions and node involvement. Patients with high TAA and VSA had a particularly poor prognosis. It is suggested that although cancer angiogenic activity is important for the local invasion and dissemination into vessels and lymphatics, the VSA may be important for the effective formation of viable tumor foci in lymph nodes or distant organs. Recognition and quantification of the vascular survival ability in human tumors may significantly improve the prognostic value of the assessment of tumor vasculature, and may help to stratify patients for clinical trials with novel anti-angiogenic or angiotoxic drugs. Elucidation of the pathways may provide additional targets for antiangiogenic therapy. This revised version was published online in July 2006 with corrections to the Cover Date.     

Nucleus basalis lesions in neonate rats induce a selective cortical cholinergic hypofunction and cognitive deficits during adulthood

Summary Ibotenic acid was infused into the nucleus basalis magnocellularis (nBM) of 2-day old rats to eliminate immature cholinergic neurons before they develop functional synaptic connections in the neocortex. For bilaterally lesioned neonates, cognitive testing was initiated 2 months after lesioning and animals were sacrificed at 8 or 12 months of age. Lesioned animals exhibited a marked deficit in the retention of passive avoidance behavior, as well as in the acquisition of 2-way active avoidance behavior. Lesioned animals also made significantly more alternation errors than control animals in the Lashley III spatial maze and showed severe impairments in general learning, reference memory and working memory during 17-arm radial maze testing. For all 4 tasks, neonatally lesioned animals did not show any recovery to the performance level of control animals. Histological analysis of the subcortex from lesioned animals during adulthood revealed: (1) a substantial reduction in acetylcholinesterase-positive cells (presumably cholinergic) within the nucleus basalis, (2) decreased acetylcholinesterase staining in neocortex and (3) a gliosis essentially restricted to the globus pallidus. Surrounding brain regions were apparently not damaged as a direct result of excitotoxin infusion. Neurochemically, neonate nBM lesioning produced a long term cholinergic hypofunction as evidenced by significant reductions of 25% and 18% in frontal cortex chorine acetyltransferase (CAT) activity at 12 and 8 months of age, respectively. By contrast, prefrontal cortical concentrations of biogenic amines and their metabolites were unaffected, thus indicating a degree of neurochemical specificity for these neonatal nBM lesions. The persistant cortical cholinergic hypofunction in lesioned animals may be related to the long term deficits in learning/memory abilities that were also observed. It is suggested that neonatal nBM lesioning could provide a useful animal model for elucidating the plasticity of the developing brain after cortical anervation.