Morphological variability, lectin binding and Na+,K+-activated adenosine triphosphatase activity of isolated Müller (glial) cells from the rabbit retina

Rabbit retinal Müller cells were isolated by means of papaine and mechanical dissociation. These cells were shown to have a well preserved morphology and to preserve viability for many hours. Intense wheat germ agglutinin binding occurs on the photoreceptor side of Müller cells, especially in the microvillous region. Rabbit retinal Müller cells have a Na+,K+-activated adenosine triphosphatase activity in the same order of magnitude as brain astroglial cells.     

A human B cell differentiation antigen selectively expressed on mature B cells identified by a monoclonal antibody (HB-2)

A monoclonal IgM antibody (HB-2), produced against a membrane antigen on the Raji, B cell line, reacted by indirect immunofluorescence with 2 to 40% of lymphoblasts from the B cell lines, Raji, Daudi, SN-1036, and SB but not with other types of cell lines, including pre-B, myeloid, melanoma, or T cells. HB-2 antibody reacted with 10 ± 3% of normal blood mononuclear cells, and was unreactive with monocytes, granulocytes, platelets, or erythrocytes. Two-color immunofluorescence revealed that HB-2 antigen expression was confined to cells bearing surface Ig. An interesting finding was the fact that 25% of plasmablasts induced by pokeweed mitogen also expressed the HB-2 antigen. However, pre-B and plasma cells from normal bone marrow did not express the HB-2 antigen either on their membrane surface or in their cytoplasm. Analysis of 85 leukemias revealed that the HB-2 antigen was expressed on acute and chronic B cell leukemias and Burkitt's lymphomas, but not on malignacies of pre-B, T, myelocytic, or plasma cells. The results suggest that expression of the HB-2 antigen is confined to mature B cells.     

Placental site trophoblastic tumor of the mediastinum

Choriocarcinoma has been described as the most frequent subtype of mediastinal germ cell tumors showing trophoblastic differentiation. We report a unique case of a placental site trophoblastic tumor, which developed in the mediastinum of a 14-year-old boy 2 years after the resection of a mature teratoma. The recurrent tumor was composed of a grossly hemorrhagic and necrotic mass. Histologically, diffusely infiltrating large polygonal cells with focal nodular growth and a teratomatous part containing mature intestinal, respiratory, and squamous epithelium with adjacent cutaneous adnexal structures were found. The typical morphologic features included vessel wall infiltration by the neoplastic cells with fibrinoid deposits and geographic necroses within the tumor masses. Characteristic diffuse positivity for melanoma cell adhesion molecule and human leucocyte antigen G was found on immunohistochemical investigation, confirming the diagnosis of placental site trophoblastic tumor. The patient died 1 year later after polychemotherapy. The outcome of this rare tumor is similar to the reported poor clinical outcome in patients with mediastinal choriocarcinomas.     

Anti-neutrophil cytoplasmic antibodies (ANCA) in ulcerative colitis: anti-cathepsin G and a novel antibody correlate with a refractory type

We analysed the clinical significance of ANCA in patients with ulcerative colitis. On either an indirect immunofluorescence assay or an ELISA with fixed neutrophils, 71% (25/35) of the patients were positive for ANCA. However, only half of them reacted with either cathepsin G or lactoferrin. Western blot assays revealed positive bands in 40% (10/25) of the antibody-positive patients. The sizes of the bands detected were ≈58, 47, 44, 40, and 28 kD. No significant correlation was found between the ANCA positivity and various variables, i.e. disease activity, extent of lesion, or treatment of the disease. The anti-cathepsin G and 28-kD positivity, however, significantly correlated with a refractory type of ulcerative colitis.     

Two types of transient outward currents in cardiac ventricular cells of mice

Ventricular cells of adult mice were prepared by an enzyme digestion procedure. Single channel currents were recorded by a conventional patch clamp technique from cell attached patches. Voltage steps from the holding potential of –80 mV to test potentials between –35 and +50 mV caused openings of two types of outward currents through single channels with the conductances of 27 and 12 pS, respectively. The averaged currents reveal transient time courses for both channel types. The current-voltage relations of both single channel currents were linear over the tested voltage range and intersected the voltage axis at –70 mV. This indicates that both single channel currents are mainly carried by potassium ions. All open and closed times were found to be voltage independent. The 27 pS channel had a mean open time of 3.9±1.0 ms (n=8). The closed time consisted of two components with ₁ = 2.1 ± 0.2 ms and ₂ = 50 ± 19 ms (n=8). The 12 pS channel had a mean open time of 34.0±5.2 ms (n=3) and the two components of the mean closed time have been calculated as ₁ = 8.3 ± 2.1 ms and ₂ = 120 ± 50 ms (n=3; all mean ±SD).     

Time-dependent study of the antibody response to sperm-whale myoglobin: recognition of the antigenic sites is unaltered over an extended period of immunization

We have recently shown that the antigenic structure of sperm-whale myoglobin is not dependent on the host species in which the antisera are raised. The purpose of the present work was to determine whether or not the molecular immune recognition of a protein by antibody is subject to a time-dependency. We have investigated the recognition of the antigenic sites by serial antisera obtained in two rabbits at different times after the initial immunization, from the earliest bleeding with detectable antibodies (9 days) up to a year. The specificity of these antisera was determined by their cross-reactions with 13 myoglobins from different species. The reactivity was measured by quantitative immunoadsorbent titration studies from the amount of radioiodinated antibodies that could be bound maximally (i.e. plateau binding values) by immunoadsorbents of each myoglobin. From these studies and our recent structural analysis, which enabled us to identify for each of these myoglobins the regions retaining reactivity with antibodies to sperm-whale myoglobin, we have concluded that following maturation of the immune response the antigenic recognition of a protein (i.e. the regions that are recognized as antigenic) is not dependent upon the time antisera are obtained after the first immunization. In the early periods of the response, fluctuations are observed in the relative immunodominance of the sites. This further confirms our earlier conclusions that the antigenic sites on a protein are structurally inherent in the protein.     

SELECTIVE HABITUATION OF GALVANIC SKIN RESPONSE COMPONENT OF THE ORIENTATION REACTION TO AN AUDITORY STIMULUS

The prediction from Sokolov's (1960) theory that, following OR habituation, size of OR return is proportional to the amount of difference between the new stimulus and the habituating stimulus was tested using an auditory stimulus varying in frequency and intensity. Five Ss were allocated to each of 16 conditions, three conditions involving changes in frequency, three involving changes in intensity, nine involving changes in both frequency and intensity, with one control condition involving a repetition of the habituating stimulus. Following habituation of the GSR component of the OR to a criterion of response failure for three successive trials, magnitude of GSR under the 16 conditions was measured. Contrary to Sokolov's theory, only increase in intensity had a significantly different effect on OR return. More importantly, it was found that Ss habituating rapidly to the initial stimulus were less likely to show OR return to stimulus change. It was concluded that individual differences in habituation rate may be more important than stimulus difference effects in selective habituation.     

HLA antigens, psoriasis and acute anterior uveitis in Bechterew's syndrome (ankylosing spondylitis)

One hundred and twenty-two consecutively hospitalized patients with ankylosing spondylitis (AS) were reexamined. Ninety-two per cent were HLA B27 positive. Of the HLA B27 negative patients, 60% were found to have psoriasis, as opposed to 11 % of the HLA B27 positive patients. Acute anterior uveitis (AAU) was found only in HLA B27 positive patients, and more frequently in males than in females. The genetic and clinical heterogeneity of AS, together with the overlapping clinical criteria for AS and psoriatic spondylitis, may make the term "Bechterew's syndrome" preferable. Based on these findings and previous reports, we conclude that (i) AAU is a manifestation of Bechterew's syndrome in HLA B27 positive patients, (ii) HLA B27 negative patients without any obvious accompanying manifestations may suffer from psoriatic spondylitis, and (iii) genetic predisposition to psoriasis in persons who are HLA B13, B17 and B37 negative, may interact with the genetic predisposition to Bechterew's syndrome in HLA B27 positive persons and produce Bechterew's syndrome with psoriasis or psoriasis-like skin eruptions.     

Association analysis of a polymorphism in the G‐protein stimulatory α subunit in patients with major depression*

Growing evidence suggests that G‐proteins may be involved in pathogenesis and treatment of affective disorders. Several studies have reported altered levels and/or activities of stimulatory G‐proteins in depression. The aim of this study was to investigate whether a polymorphism in the stimulatory α subunit of G‐proteins (T/C point mutation in exon 5; ATT → ATC at codon 131) is associated with major depression or response to antidepressant treatment. Therefore, we performed a case‐control association study with 212 depressive patients and 137 healthy, unrelated controls. There was no evidence for an association between the investigated polymorphism in the Gα_s gene and major depression, as well as to treatment response. The results of our study are in concordance with recently published findings which do not support the hypothesis that the gene for the stimulatory α subunit of G‐proteins is a major susceptibility factor in the pathophysiology of major depression. © 2002 Wiley‐Liss, Inc.