Selectivity of inferior temporal neurons for realistic pictures predicted by algorithms for image database navigation

Primates have a remarkable ability to perceive, recognize, and discriminate among the plethora of people, places, and things that they see, and neural selectivity in the primate inferotemporal (IT) cortex is thought to underlie this ability. Here we investigated the relationship between neural response and perception by recording from IT neurons in monkeys while they viewed realistic images. We then compared the similarity of neural responses elicited by images to the quantitative similarity of the images. Image similarity was approximated using several algorithms, two of which were designed to search image databases for perceptually similar images. Some algorithms for image similarity correlated well with human perception, and these algorithms explained part of the stimulus selectivity of IT neurons. Images that elicited similar neural responses were ranked as more similar by these algorithms than images that elicited different neural responses, and images ranked as similar by the algorithms elicited similar responses from neurons. Neural selectivity was predicted more accurately when the reference images for algorithm similarity elicited either very strong or very weak responses from the neuron. The degree to which algorithms for image similarity were correlated with human perception was related to the degree to which algorithms explained the selectivity of IT neurons, providing support for the proposal that the selectivity of IT neurons is related to perceptual similarity of images.     

Natural human polyreactive IgM induce apoptosis of lymphoid cell lines and human peripheral blood mononuclear cells

Natural polyreactive IgM autoantibodies, encoded by unmutated germline Ig V genes, represent a major fraction of the normal circulating IgM repertoire. We have previously shown that therapeutic preparation of pooled IgM exerts immunomodulatory effects as assessed by in vitro and in vivo studies. Here, we show that the IgM preparation induces cell death in lymphoblastoid cell lines and in human peripheral blood mononuclear cells. The IgM-induced cell death involved classical features of apoptosis such as nuclear fragmentation and activation of caspases. Treatment of leukemic cells with IgM resulted in the cleavage of poly-(A)DP ribose polymerase, a substrate of caspase, and in a reduction in mitochondrial transmembrane potential during the early period of apoptosis induction. Natural IgM-induced apoptosis was inhibited by soluble Fas molecules and affinity-purified Fas antibodies from pooled IgM preparation induced apoptosis in lymphoblastoid cells, suggesting the involvement of the Fas receptor. Our results suggest a role for normal IgM in controlling cell death and proliferation, and imply a possible therapeutic role for IgM in autoimmune and lymphoproliferative disorders.     

Influence of chlorpromazine on the rabbit electroretinogram

In anesthetized albino or nonalbino rabbits, a 3 to 8 mg/kg IV injection of chlorpromazine did not affect a-wave amplitude of the electroretinogram (ERG). However, immediately after the injection of the drug, b-wave amplitude increased. The maximum increase occurred between 35 to 50 min, and the recovery time varied between 5 to 8 hr. Initial changes in the b-wave amplitude to some extent were affected by systemic changes in the blood pressure. However, the b-wave amplitude remained high for a long time after the blood pressure reached preinjection value, indicating a local effect of the drug. There was no change in a- or b-wave latencies. Although in vitro a large quantity of chlorpromazine can be localized in the melanin granules from pigmented rabbit retina, in vivo the ERG b-wave changes caused by the small intravenous dose of the drug were similar in both albino and nonalbino rabbits.     

Hematuria due to urolithiasis in a child with chronic immune thrombocytopenic purpura

Hematuria is an uncommon manifestation of chronic immune thrombocytopenic purpura. The occurrence of urolithiasis in children with chronic immune thrombocytopenic purpura has not been described. We report a case of hematuria due to urolithiasis in an 8-year-old boy with chronic immune thrombocytopenic purpura. This child, who had a history of immune thrombocytopenic purpura of 1 year's duration, presented to the emergency department with gross hematuria. The cause of hematuria was initially attributed to his primary disease process. A careful history, examination, and pertinent investigations revealed that the hematuria was secondary to urolithiasis. This report highlights the need to keep an open mind and to search for specific causes of bleeding, even in children with known bleeding disorders.     

Enteropathy-Associated T-Cell Lymphoma

Enteropathy-associated T-cell lymphoma is a rare neoplasm with uniformly aggressive features that arises from intestinal T-cells. There is strong evidence supporting its association as a dire complication of celiac disease. The clinical presentation can vary from malabsorption and abdominal pain to an acute abdominal emergency. Originally, it was divided into types I and II in World Health Organization (WHO) classification schemes, reflective of epidemiology and differences in clinicopathologic features. The debate over the degree of separation of the two types is ongoing as new data emerges regarding the pathogenetics. The low incidence and variable patient factors are major barriers in conducting clinical trials and establishing standard treatment regimens. Yet, the collective experience demonstrates favorable outcomes with combination chemotherapy followed by an autologous hematopoietic stem cell transplant in patients who can tolerate such treatment. The prognosis remains dismal; thus, future research studies are warranted to identify effective novel therapies that can improve outcomes in this rare disease entity.     

Expansion of CD4+CD25+ regulatory T cells by intravenous immunoglobulin: a critical factor in controlling experimental autoimmune encephalomyelitis

The clinical use of intravenous immunoglobulin (IVIg) based on its immunomodulatory and anti-inflammatory potential remains an ongoing challenge. Fcgamma receptor-mediated effects of IVIg, although well elucidated in certain pathologies, cannot entirely account for its proven benefit in several autoimmune disorders mediated by autoreactive T cells. In this study, we show that prophylactic infusion of IVIg prevents the development of experimental autoimmune encephalomyelitis (EAE), an accepted animal model for multiple sclerosis (MS). The protection was associated with peripheral increase in CD4+CD25+Foxp3+ regulatory T cell (Treg) numbers and function. The protection was Treg-mediated because IVIg failed to protect against EAE in mice that were depleted of the Treg population. Rather than inducing de novo generation from conventional T cells, IVIg had a direct effect on proliferation of natural Treg. In conclusion, our results highlight a novel mechanism of action of IVIg and provide a rationale to test the use of IVIg as an immunomodulatory tool to enhance Treg in early onset MS and other autoimmune and inflammatory conditions.