Aberrant T-regulation in rheumatoid arthritis and IgA nephropathy affects CD5+ and CD5- B lymphocytes equally.

T-suppressor function and T-helper function in healthy adults, elderly patients with non-immune diseases, and patients with rheumatoid arthritis (RA) and IgA nephropathy (IgAN) were titrated by adding graded concentrations of CD8+ cells to autologous CD8-depleted peripheral blood mononuclear cells (PBMC), or CD4+ cells to CD8- 4- PBMC, respectively. Following culture with pokeweed mitogen (PWM), numbers of CD5+ and CD5- immunoglobulin-secreting cells were determined using a combination of rosetting with anti-CD5-coated Dynabeads and reverse haemolytic plaque formation (Jones, 1990). Of 11 RA patients studied, eight had slightly reduced suppressor activity for CD5+ and CD5- IgM-secreting cells, and three with active disease and high serum levels of C-reactive protein, could not suppress IgG, IgA or IgM secretion by either B subset. Helper activity for both CD5+ and CD5- B cells was slightly but significantly increased in RA patients. One of eight patients with IgAN could not suppress IgG, IgA or IgM production by CD5+ or CD5- B cells, and all IgAN patients required strikingly fewer CD4+ cells for PWM-induced activation of CD5+ and CD5- B cells than controls. It was concluded that in two immunologically mediated diseases in which some patients have raised numbers of circulating CD5+ B cells, aberrant T-regulation affects CD5+ and conventional CD5- B cells equally.     

Repeated DNA sequence involved in mutations affecting transport of sucrose into Streptococcus mutans V403 via the phosphoenolpyruvate phosphotransferase system.

Mutants of Streptococcus mutans V403 defective in the intracellular sucrose-6-phosphate hydrolase (product of the scrB gene) are sensitive to sucrose because of the intracellular accumulation of the phosphorylated sugar. Using a scrB mutant prepared by allelic exchange, we have isolated and characterized a number of sucrose-resistant revertants. One such mutant was found to lack the ability to transport sucrose into the cell via the phosphoenolpyruvate-dependent sucrose phosphotransferase system (PTS). Genetic analysis of this strain revealed this lesion to be linked to the scrB gene. This was corroborated by the physical demonstration of an insertion mutation very near scrB. Taken together with DNA sequence information (Y. Sato, F. Poy, G. R. Jacobson, and H. K. Kuramitsu, J. Bacteriol. 171:263-271, 1989), our results indicated that all of the mutations characterized were located in the adjoining scrA gene which encodes the membrane-associated, sugar-specific enzyme II (EIIsucrose) component of the sucrose PTS in S. mutans. Biochemically, such a genetic lesion disables the sucrose PTS and prevents sucrose from entering the cell by this system. In this paper, we detail the nature of two independent insertion mutations and conclude them to be the result of duplicative transposition events into the scrA gene. This region of the chromosome was amplified and purified in large quantities by using the polymerase chain reaction. Examination of the amplified DNA revealed that the two independent insertion mutations were composed of sequences that were indistinguishable by size and by restriction site endonuclease maps. Their insertion points in the scrA gene were approximately 200 bp apart. The amplified DNA fragment was also used as a probe to demonstrate the presence of five copies of this element on the S. mutans V403 chromosome. A second strain, S. mutans V310, also was found to carry similarly arranged, multiple copies of this sequence on its chromosome, suggesting a clonal origin of V403 and V310. The small size of this sequence, its presence in multiple copies on the V403 chromosome, and its ability to duplicate itself semiconservatively into remote sites argue compellingly that it is an insertion sequence element. One such insertion mutant, with a defective sucrose PTS, was tested for virulence in rats and was found to cause caries at levels similar to those of the wild-type strain.     

A Survey of Laboratory Computers in Psyehophysiology

Since the mid 196O's there has hcen a growing interest in and use of computers in psychophysiology laboratories. There are even a growing number of accepted physiological measures which are fully dependent on computer technology for their derivation. Although minicomputers have been in use for over a decade, recent developments in microcomputer and microprocessor technology have led to rapid acceptance of microcomputers for laboratory work. These rapid advances have produced a need to survey the current state of laboratory computer applications and development. A comprehensive survey was mailed to 301 psychophysiology laboratory groups during the spring and summer of 1979 and completed surveys were received from 61% of the mailing. Sun'ey results are reported on computer hardware and configuration, dependent measures and user satisfaction, and use and cost of engineering and programming support. Developments in computer hardware and user services are also discussed.     

Properties of receptors for IgG on human placental cell membranes

The amount of 125I-IgG which bound to membranes isolated from the human placenta was competitively inhibited by the presence of increasing amounts of unlabeled IgG but not by unlabeled albumin. The relationship between membrane-bound and free IgG indicated the presence of membrane receptors with an appreciable affinity for IgG. Incubation of membranes with collagenase or neuraminidase did not results in appreciable reduction of IgG-membrane binding, indicating that neither intact collagen nor sialic acid play an important role in the binding. Placental surface membranes isolated by salt extraction bound 3.79+/- 1.78 (SD) pmol IgG/microgram membrane protein, whereas membranes isolated by differential centrifugation bound only 1.61 +/- 0.24 pmol/microgram (p less than 0.02). The fraction of a preparation of solubilized membranes which bound to an IgG affinity column yielded on polyacrylamide gel electrophoresis three prominent protein bands which had molecular weights of 3.7 X 10(4), 4.5 X 10(4) and 6.0 X 10(4) daltons. These findings are consistent with the existence of a limited number of receptors for IgG on placental membranes, including IgG receptors on the microvillus membrane of the syncytial trophoblast. The latter, in accordance with Brambell's hypothesis, could be of importance in the transplacental transport of maternal IgG.     

Increased fibronectin production by cell lines from hypertrophic scar and keloid

Primary cell lines of fibroblasts from 8 tissues were established--three from hypertrophic scars (HS), one keloid (K) and four from the normal uninvolved dermis adjacent to each lesion. The objective was to quantify and compare all eight cell lines on the basis of fibronectin (FN) produced per cell and per total protein (PR). Two hypertrophic scars and their adjacent skin cell lines were evaluated by the ELISA method for FN and a micro Lowry assay for PR. The scar lines showed statistically significant increases in the amount of FN/cell compared to the cell lines from their adjacent normal dermis. The third hypertrophic scar and the keloid with their adjacent skin cell lines were assayed for FN and PR by radioimmunoprecipitation. Subconfluent cells were metabolically labeled with 35S-methionine for 20 hours. Harvested media and cell monolayers were assayed for radioactivity incorporated into FN and PR. The percentage of FN/PR was significantly higher in media for HS and K compared to the adjacent normal skin lines in the three passages tested. These results support our previous immunofluorescence studies and demonstrate that a fibroblast-type cell line from a hypertrophic scar or keloid produces more FN/PR over time than the normal fibroblast-type cell line from adjacent uninvolved dermis.     

Non-Hodgkin's lymphomas: an immunohistochemical and histological study.

Immunohistochemical and histoogical studies have been performed on paraffin sections of 19 cases of non-Hodgkin's lymphoma (NHL). All the cases were lymphocytic in type and, on the basis of the National Lymphoma Investigation classification, 11 were follicular (six small, three mixed small and large, and two large cell types) and eight were diffuse (four intermediate, three poorly and one well-differentiated types). Marshall's metalophil method revealed a population of dendritic histiocytes in and around the follicles of follicular lymphomas. The distribution of the dendritic cells within the neoplastic follicles resembled the distribution of similar cells in reactive follicles, lending support to the concept of an origin for lymphoma follicles from their reactive counterparts. In the diffuse lesions the dendritic cells were large and more pleomorphic than in the follicular lesions, but these features were not so pronounced as those previously observed in Hodgkin's disease. The PAP sequence was used to demonstrate Ig, and as judged by the types of light and heavy chains in the lymphoma cells, the cases were divided into three groups: Group 1 (eight cases) in which the lymphoma cells contained monotypic Ig; Group 2 (six cases) in which monotypic Ig was probably present; and Group 3 (four cases) where no evidence of monotypic Ig secretion was found. Monotypic Ig was most commonly found in follicular lymphomas, mu kappa secretion being the most frequently identified combination of heavy and light chains. The majority of cases (73 per cent.) were thus clearly derived from B lymphocytes. However, the fact that monoclonality was evident in only a proportion of cases suggested that lymphomas may be polyclonal initially and proportion of cases suggested that lymphomas may be polyclonal initially and that monoclonality is a later development. In addition to the lymphoma cells, normal mature plasma cells containing a high concentration of intracellular Ig were present in all but one of the lesions. The Ig was polytypic, cells containing kappa and lambda chains being present in roughly equal numbers and gamma chains pre-dominating. Extracellular Ig (gamma, mu, kappa, lambda) was also present in many lesions. Collections of small non-lymphomatous lymphocytes were also present in all cases. In eight lesions these appeared to have polytypic surface Ig (mu, kappa, lambda). Dendritic cells mingled with these lymphocytes. Collections of small lymphocytes non-reactive for Ig were also present. These had no association with dendritic histiocytes and might have been T cells. It is concluded that in most cases immunohistochemistry alone provides an insufficient basis for the diagnosis of lymphoma and that disturbance of cellular morphology and tissue architecture remain the most useful criteria on which the diagnosis of lymphoma rests.     

Glutamate-induced activation of rat locus coeruleus increases CA1 pyramidal cell excitability

In anesthetized rats, injections of a 0.5 mM glutamate solution into the locus coeruleus (LC) reversibly increased the amplitude of the population spike evoked in CA1 by stimulation of the Schaffer-commissural fiber tract. This effect was absent in N-(2-chloroethyl)-N-ethyl-2-bromobenzylamine (DSP-4)-treated, noradrenaline (NA)-depleted animals. The excitatory postsynaptic potential recorded in the stratum radiatum was unaffected following the glutamate injections. Systemic administration of the NA-uptake inhibitor desipramine also produced an increase in population spike amplitude. The findings demonstrate that activation of LC neurons increases pyramidal cell excitability in vivo.     

Maturation of pyramidal cell form in relation to developing afferent and efferent connections of rat somatic sensory cortex.

Golgi and axonal labeling methods were used to examine the maturation of pyramidal cells in layers III and V of the rat somatic sensory cortex. The material came from animals late in the gestation period, postnatal, ranging from 0 to 43 days of age and at maturity. Special attention was paid to the period (0–7 days of age) during which it is known that thalamic and callosal fibers grow into the cortex. It is shown that the basic features of the pyramidal cell form are established before the long afferent fibers arrive in layers III and V and before the large number of synapses are established in these layers. Nevertheless, considerable dendritic growth and spine formation occurs after the afferent fibers establish an adult-like pattern of distribution. It is also shown that even at 1 day of age, the axons of pyramidal cells in all layers have reached the vicinity of targets such as the striatum, thalamus, brainstem, spinal cord and contralateral cortex.At 0–1 day the immature pyramidal cells are essentially bipolar in the upper cortical plate, but in the developing infragranular layers they have a few short, almost spine-free, basal dendrites and, rarely, a few oblique branches of the apical dendrite. The apical dendrite extends to the pial surface and the dendritic branches end in growth cones. The dendrites of cells in all layers increase in size and complexity of branching over the first postnatal week; the maturation of dendrites in layer V leads that of dendrites in the supragranular layers by about 2–3 days. As maturation proceeds, basal dendrites acquire secondary and tertiary branches and more oblique branches appear on the apical dendrite. Dendritic spines appear after 4 days of age but remain sparse up to 7–8 days. At 14 days of age, the spine density is much higher than in 7-day-old animals but remains at a much lower density than in 4-week-old, 6-week-old, or adult animals. By 7–14 days, the difference in maturity between superficial (layer III) and deep (layer V) pyramidal cells is difficult to discern qualitatively. All the pyramidal cells now have relatively complex, highly branched dendritic trees when compared to younger cells, but the dendritic tree is still immature in terms of the number, length and complexity of branching of the apical and basal dendritic systems.It can be concluded that the growth of the long axon of cortical pyramidal neurons precedes the acquisition of afferent connections and when these afferent fibers arrive in the cortex the dendritic tree of the pyramidal cell is still highly immature. Thus it remains possible that the finer modeling of the dendritic tree and the formation of spines may be affected by extrinsic influences such as the afferent fibers.     

Oral vaccination against Porteus mirabilis.

Mice given a single dose of proteus vaccine orally were protected against 1 MLD (minimum lethal dose) of autologous Proteus mirabilis by the fourth day after vaccination. Three doses of oral vaccine induced protection against 1 MLD autologous challenge for 7 days after vaccination and partial protection for a further 8 weeks. Cross-protection against different strains of Pr. mirabilis and against some strains of Pseudomonas aeruginosa, Serratia marcescens and Providencia species was found in mice immunized orally on three consecutive days with a bivalent proteus vaccine.