Presence of immunoglobulin M antibodies around the glomerular capillaries and in the mesangium of normal and passive Heymann nephritis rats

Summary Diffuse distribution of small, faintly staining, beaded deposits of rat immunoglobulin M (IgM) around the glomerular capillary blood vessels, and a more intensely staining larger deposition in the mesangium, were observed on the kidney sections of normal rats. As glomerular-fixed nephritogenic antigens are known to be present on the epithelial aspect of the glomerular basement membrane (GBM), especially at the soles of foot processes and at the slit pores, it was assumed that the IgM antibodies were directed against these antigens. Investigation by immunofluorescent antibody double-staining techniques of rat kidney sections obtained from normal and rabbit anti-FX1A-injected rats stained for the nephritogenic antigen showed that a number of antigenic sites in the glomeruli and in the mesangium shared antibody hits by heterologous rabbit IgG and autologous rat IgM antibodies. Most sites in the glomeruli stained specifically for rat IgM or rabbit IgG, but preferentially for the latter. The intensely fluorescent mesangial deposits stained mainly for rat IgM, indicating that at these sites the antigenic material was virtually saturated, while areas at the entry to the mesangial space also stained for rabbit IgG, indicating that at these locations free nephritogenic epitopes were still available for reaction with the anti-FX1A antibody. Western blot analysis have shown that the rabbit anti-rat FX1A IgG and the rat anti-rat KF3 IgM antibodies are directed against the same renal tubular-derived antigen with a molecular weight of 70,000. These experimental findings collectively demonstrate that the heterologous IgG and autologous IgM antibodies are directed against the same nephritogenic antigen, which is found in the glomeruli, the mesangium and the proximal convoluted tubules. Thus, the IgM autoantibody has a possible physiological role but, in addition, there is evidence of active immunophagocytic events, manifested in a rapid and continuous entrapment and expulsion of macromolecules after their processing by the mesangial cells of normal and passive Heymann nephritis rats.     

In vitro effector activity of Pneumocystis murina-specific T-cytotoxic-1 CD8+ T cells: role of granulocyte-macrophage colony-stimulating factor

Human immunodeficiency virus (HIV)-related opportunistic infections continue to occur in patients who are newly diagnosed with HIV infection, those in the early course of highly active antiretroviral therapy or nonadherent to HIV care, and other immunosuppressed individuals. One of the most common opportunistic infections in these patients is Pneumocystis pneumonia. CD8+ T cells are recruited to the lung after P. carinii infection and have been associated with both lung injury and host defense. This variability may be due to subpopulations of CD8+ T cells recruited to the lung. We have previously shown using adoptive transfer studies that in vivo-generated T-cytotoxic-1 (Tc1) CD8+ T cells, defined by the secretion of gamma interferon (IFN-gamma), have effector activity against Pneumocystis spp. in vitro as well as in vivo. To better understand the mechanisms of these effects, we generated, expanded, and tested Tc1 and Tc2 CD8+ T cells specific for P. murina ex vivo. Tc1-polarized CD8+ T cells secreted higher levels of IFN-gamma and granulocyte-macrophage colony-stimulating factor (GM-CSF) and lower levels of interleukin-4 (IL-4), IL-5, IL-10, and IL-13 than Tc2 CD8+ T cells when stimulated with P. murina antigen. Moreover, Tc1 CD8+ T cells demonstrated enhanced effector activity in a macrophage-mediated killing assay which was independent of cell contact. The augmentation in macrophage-mediated P. murina killing was significantly abrogated when GM-CSF was neutralized in the Tc1 CD8+ T cells. These data support the possibility that antigen-specific GM-CSF secretion is critical for effector activity of P. murina-specific Tc1 CD8+ T cells in vitro.     

Family interaction and the development of borderline personality disorder: a transactional model

Although no prospective epidemiological studies have evaluated the relationship between family interactions and the development of borderline personality disorder (BPD), there is considerable evidence for the central role of family interactions in the development of BPD. This paper describes the role of family interactions or processes, especially those that might be regarded as invalidating or conflictual, negative or critical, and the absence of more validating, positive, supportive, empathic interactions, in the development of BPD. Perhaps more importantly, the proposed model considers how these parental and family behaviors transact with the child's own behaviors and emotional vulnerabilities, resulting in a developmental model of BPD that is neither blaming of the family member with BPD nor of her or his parents and caregivers, and has important and specific implications for both prevention and intervention.     

Human leukocyte antigen-DQ8 transgenic mice: a model to examine the toxicity of aerosolized staphylococcal enterotoxin B

Staphylococcal enterotoxins (SEs) belong to a large group of bacterial exotoxins that cause severe immunopathologies, especially when delivered as an aerosol. SEs elicit the release of lethal amounts of cytokines by binding to major histocompatibility complex (MHC) class II and cross-linking susceptible T-cell receptors. Efforts to develop effective therapeutic strategies to protect against SEs delivered as an aerosol have been hampered by the lack of small animal models that consistently emulate human responses to these toxins. Here, we report that human leukocyte antigen-DQ8 (HLA-DQ8) transgenic (Tg) mice, but not littermate controls, succumbed to lethal shock induced by SEB aerosols without potentiation. Substantial amounts of perivascular edema and inflammatory infiltrates were noted in the lungs of Tg mice, similar to the pathology observed in nonhuman primates exposed by aerosol to SEB. Furthermore, the observed pathologies and lethal shock correlated with an upsurge in proinflammatory cytokine mRNA gene expression in the lungs and spleens, as well as with marked increases in the levels of proinflammatory circulating cytokines in the Tg mice. Unlike the case for littermate controls, telemetric evaluation showed significant hypothermia in Tg mice exposed to lethal doses of SEB. Taken together, these results show that this murine model will allow for the examination of therapeutics and vaccines developed specifically against SEB aerosol exposure and possibly other bacterial superantigens in the context of human MHC class II receptors.     

Phenotypic evaluation of the basal-like subtype of invasive breast carcinoma.

Microarray profiling of invasive breast carcinomas has identified five distinct subtypes of tumors (luminal A, luminal B, normal breast-like, HER2 overexpressing, and basal-like) that are associated with different clinical outcomes. The basal-like subtype is associated with poor clinical outcomes and is the subtype observed in BRCA1-related breast cancers. The aim of this study was to characterize the histologic and immunophenotypic properties of breast basal-like carcinomas that were first positively identified using DNA microarray analysis. Detailed histologic review was performed on 56 tumors with known microarray profiles (23 basal-like, 23 luminal, and 12 HER2+). Immunohistochemistry for estrogen receptor (ER), HER2, EGFR, smooth muscle actin (SMA), p63, CD10, cytokeratin 5/6, cytokeratin 8/18, and vimentin was performed on 18 basal-like, 16 luminal, and 12 HER2+ tumors. The basal-like tumors were grade 3 ductal/NOS (21/23) or metaplastic (2/23) carcinomas that frequently showed geographic necrosis (17/23), a pushing border of invasion (14/23), and a stromal lymphocytic response (13/23). Most basal-like tumors showed immunoreactivity for vimentin (17/18), luminal cytokeratin 8/18 (15/18), EGFR (13/18), and cytokeratin 5/6 (11/18), while positivity for the myoepithelial markers SMA (4/18), p63 (4/18) and CD10 (2/18) was infrequent. All basal-like tumors tested were ER- and HER2-. Morphologic features significantly associated with the basal-like subtype included markedly elevated mitotic count (P<0.0001), geographic tumor necrosis (P=0.0003), pushing margin of invasion (P=0.0001), and stromal lymphocytic response (P=0.01). The most consistent immunophenotype seen in the basal-like tumors was negativity for ER and HER2, and positivity for vimentin, EGFR, cytokeratin 8/18, and cytokeratin 5/6. The infrequent expression of myoepithelial markers in basal-like carcinomas does not support a direct myoepithelial cell derivation of these tumors. These findings should further assist in the identification of basal-like carcinomas in clinical specimens, facilitating treatment and epidemiologic studies of this tumor subtype.     

Steroid hormone receptors in human salivary gland tumours.

Major salivary gland tumours were studied for the presence of hormone receptors for oestrogen and progesterone. Of the eight salivary gland tumours exhibiting varied histology, none showed high affinity receptors for oestrogen or progesterone. Salivary tissue from four patients with non-neoplastic salivary gland disease was also studied and found not to contain high affinity receptor sites. The absence of hormone receptors in these glands suggests that such tumours are not dependent on endocrine function.     

Type 2 Gaucher Disease with Hydrops Fetalis in an Ashkenazi Jewish Family Resulting from a Novel Recombinant Allele and a Rare Splice Junction Mutation in the Glucocerebrosidase Locus

Gaucher disease, the deficiency of the lysosomal enzyme glucocerebrosidase (EC 3.2.1.45), is frequently encountered in the Ashkenazi Jewish population. Carrier screening for Gaucher disease by enzyme analysis performed during a routine pregnancy indicated that both Ashkenazi parents were carriers. Screening for four common Gaucher mutations was subsequently performed on fetal and parental DNA. None of the common Ashkenazi mutations were identified. However, when exons 9–11 were amplified and digested withNciI to detect the L444P mutation, it appeared that the mother and the fetus had an unusual allele and that the expected paternal allele was not present. When the fetal amniocytes were found to have less than 2% of the normal glucocerebrosidase activity and a fetal sonogram revealed hydrops fetalis, the pregnancy was terminated. The diagnosis of severe type 2 Gaucher disease was confirmed at autopsy. Ultrastructural studies of epidermis from the fetus revealed the characteristic disruption of lamellar bilayers, diagnostic for type 2 Gaucher disease. In subsequent studies of the fetal DNA, long-template polymerase chain reaction amplification revealed one appropriately sized band (6.5 kb) and one smaller (5.2 kb) band. Sequencing of the 5.2-kb fragment identified a novel fusion allele resulting from recombination between the glucocerebrosidase gene and its pseudogene beginning in intron 3. This fusion allele was inherited from the father. The result was confirmed by Southern blot analysis using the enzymeSstII. Sequencing of the 6.5-kb fragment identified a previously described, although rare, T-to-G splice junction mutation in intron 10 of the maternal allele, which introduced anNciI site. The couple had a subsequent pregnancy which was also found to be affected. This case study identifies a novel recombinant allele and an unusual splice junction mutation, and demonstrates that even in the Ashkenazi population, screening for common mutations may not accurately identify the most severe forms of the disease.     

Multiple mechanisms govern the dynamics of depression at neocortical synapses of young rats

Synaptic transmission between pairs of excitatory neurones in layers V ( N = 38) or IV ( N = 6) of somatosensory cortex was examined in a parasagittal slice preparation obtained from young Wistar rats (14–18 days old). A combined experimental and theoretical approach reveals two characteristics of short-term synaptic depression. Firstly, as well as a release-dependent depression, there is a release-independent component that is evident in smaller postsynaptic responses even following failure to release transmitter. Secondly, recovery from depression is activity dependent and is faster at higher input frequencies. Frequency-dependent recovery is a Ca²⁺-dependent process and does not reflect an underlying augmentation. Frequency-dependent recovery and release-independent depression are correlated, such that at those connections with a large amount of release-independent depression, recovery from depression is faster. In addition, both are more pronounced in experiments performed at physiological temperatures. Simulations demonstrate that these homeostatic properties allow the transfer of rate information at all frequencies, essentially linearizing synaptic responses at high input frequencies.