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.     

Iotrol versus metrizamide in lumbar myelography: a double-blind study

In a prospective, randomized, double-blind study, 49 patients underwent lumbar myelography using iotrol (24 patients) or metrizamide (25 patients). The diagnostic imaging adequacy of iotrol was comparable with that of metrizamide. After iotrol myelography, adverse reactions were fewer, less severe, and of shorter duration than were those following metrizamide myelography. Thirteen of 24 patients (54%) receiving iotrol reported some adverse reactions compared with 24 of 25 patients (96%) receiving metrizamide. Five moderate and one severe adverse reaction occurred in the group receiving iotrol. Fourteen moderate and eight severe adverse reactions occurred in the group receiving metrizamide. Thirty-eight patients underwent electroencephalography both before and after myelography (19 iotrol and 19 metrizamide). None of the EEGs obtained after iotrol myelography changed from baseline, while seven of the EEGs obtained after metrizamide myelography showed changes from baseline. Iotrol was judged superior to metrizamide as a contrast medium in this patient population.     

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.