Prior immunologic experience potentiates the subsequent antibody response when Salmonella strains are used as vaccine carriers.

Prior immunologic experience with homologous and heterologous serotype Salmonella strains potentiated the subsequent antibody response when the same strains were used as vaccine carriers of foreign antigens. This potentiation was positively correlated with the appearance of antibody directed against the lipopolysaccharide of the carrier strain. Both serum and mucosal antibody responses against the foreign antigen increased over time. Antibody responses in sera of animals primed with either the homologous or heterologous serotype strain were not statistically significantly different, while animals primed with the homologous serotype strain developed significantly better mucosal antibody responses against the foreign antigen.     

Localized bullous pemphigoid in a patient with primary lymphoedema tarda

We report a case of localized bullous pemphigoid (BP) in a woman patient with primary lymphoedema tarda. There is only one previous case reported of localized pemphigoid in an area of lymphoedema, this being of the cicatricial variant. Slow circulation in the lymphatic vessels, increased capillary permeability with preferential localization of antibodies in the area, and potential cleavage of the epidermal junction due to increased hydrostatic pressure leading to autoimmunity, have all been advocated as possible pathogenic mechanisms. Nevertheless, we consider that the mechanism by which localized pemphigoid arises on lymphoedema remains elusive, based on a previous case of generalized BP sparing an area of postsurgical lymphoedema.     

Cardiac involvement in Lyme disease: manifestations and management

Cardiac involvement in Lyme disease may manifest as atrioventricular block, myopericarditis, and left ventricular dysfunction. Diagnosis depends on recognition of the systemic nature of Lyme disease, including cardiac involvement, and its natural history. Serologic tests that are both sensitive and specific may aid in diagnosis. Although current recommendations for the treatment of Lyme disease with carditis include antibiotics and salicylates or corticosteroids, these types of therapy have not been unequivocally demonstrated to alter the natural history of cardiac involvement. Supportive therapy may necessitate temporary transvenous cardiac pacing in symptomatic patients.     

Alterations in glutathione and glutathione-related enzymes in a multidrug-resistant small cell lung cancer cell line

H69AR is a multidrug-resistant small cell lung cancer cell line derived from a drug-sensitive cell line, H69, by selection in doxorubicin. It is cross-resistant to a wide variety of natural product-type antineoplastic agents but does not overexpress P-glycoprotein. In the present study, the levels of GSH and GSH-related enzymes in the H69AR cell line were determined and compared with those found in H69 cells. Unlike other drug-resistant cell lines, GSH levels were diminished 6-fold in H69AR cells (0.67 +/- 0.28 microgram/mg of protein), compared with H69 cells (4.23 +/- 1.17 micrograms/mg of protein) (p less than 0.01). This unusually low level of GSH may explain the pronounced collateral sensitivity of H69AR cells to buthionine sulfoximine (BSO), an inhibitor of the rate-limiting enzyme in GSH biosynthesis (ID50 of 4.4 microM BSO for H69AR cells versus ID50 of 300 microM BSO for H69 cells). BSO did not enhance doxorubicin cytotoxicity in the H69AR cell line, despite further depletion of GSH. GSH-reductase (EC 1.6.4.2) activity was elevated 2-fold in H69AR cells, compared with sensitive H69 cells (75.34 +/- 14.94 versus 38.62 +/- 5.06 nmol of NADPH/min/mg of protein) (p less than 0.05). Both selenium-dependent and -independent GSH-peroxidase (EC 1.11.1.9) activities were unchanged in the resistant H69AR cell line, compared with its parent cell line. gamma-Glutamyl transpeptidase (EC 2.3.2.2) activity was 5-fold elevated in H69AR cells, compared with H69 cells (2.50 +/- 0.44 versus 0.46 +/- 0.21 nmol of p-nitroaniline/min/mg of protein) (p less than 0.01), whereas GSH-S-transferase (EC 2.5.1.18) activity was 10-fold higher (201.98 +/- 43.62 versus 19.77 +/- 1.72 nmol of 1-chloro-2,4-dinitrobenzene/min/mg of protein in H69AR and H69 cells, respectively) (p less than 0.01). The GSH-S-transferases from both cell lines were purified by affinity chromatography and immunoblot analysis identified the GSH-S-transferases as belonging to the anionic pi class. GSH-S-transferases from the mu or alpha classes were not detectable in either cell line. In conclusion, marked differences in GSH levels and the activities of three of four GSH-related enzymes were observed between the multidrug-resistant H69AR cell line and its parent cell line. Further study is required to determine whether these changes are causally related to the development of drug resistance in this model system.     

Automated image analysis for counting unstained cultured neurones.

A fully automated image analysis technique was developed for counting the number of live or fixed, unstained neurones present in a representative region of a cell culture dish. A dish containing cultured mouse hippocampal neurones was placed on the motorized stage of an inverted microscope, and the neurones were visualized using Hoffman modulation contrast optics. The resulting image was digitized, and processed by subtracting the background illumination, low pass filtering, thresholding, then deleting objects whose areas fell outside a specified range. Two threshold levels were used, each with its own area range, and the two resulting binary images were combined. The number of objects in the combined image was counted. The number of cells in each field was also counted manually, and the processing was repeated on a series of 100 fields covering a representative region of the dish. The automated counts were highly correlated with the manual counts for each of the 12 culture dishes examined in this study. The correlation coefficient was calculated for the manual and automated counts from each dish, and the values ranged from 0.91 to 0.97. Six of the dishes were treated with the envelope protein of the human immunodeficiency virus (gp120), which reduces survival of neurons in this system. The six treated dishes were found to have significantly fewer neurones than the six control dishes, using either manual or automated counting techniques.