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Biomedical subjects

D R Schultz

Publications and source records attributed to D R Schultz.

70 records · Page 4Linked to original sources
PubMed1975

Subcellular localization of pulmonary antiotensin-converting enzyme (kininase II).

Goat antibodies to pig lung angiotensin-converting enzyme (kininase II) were conjugated to microperoxidase. Rat lung tissue, previously incubated with non-immune goat serum, was incubated with the antibody-microperoxidase conjugate and then with H2O2 and 3,3-diaminobenzidine. Electron microscopy revealed reaction product on the plasma membrane and caveolae of endothelial cells, especially those of capillaries and venules. These results support the hypothesis that angiotensin I and bradykinin are metabolized by enzymes on the luminal surface of pulmonary endothelial cells.

Angiotensin II↗
PubMed1975

Cyanate as an inactivator of complement proteins.

Sodium cyanate added to normal human serum or serum from patients with sickle-cell disease resulted in the functional inactivation of C3, C5, C6, C7, and the C3b inactivator, but not C8 and C9. Final concentrations as low as 0.5 mM in serum caused inactivation of 12 to 64% of the C3 after 8 hr at 37 degrees C. The activity of the inactivated C3, C5, and C3b inactivator was not restored by dialysis. Most of the functional activity of C3 in cyanate-treated sera was destroyed by very small quantities of 14C-labeled cyanate that was bound to the protein. C3 inactivation by cyanate occurred in heated sera (50 degrees C, 30 min) and sera treated with EDTA, probably indicating that one mechanism for inactivation was by a direct carbamylation reaction. Both C3 and C5 showed two anodal-migrating forms in two dimensional antigen-antibody crossed electrophoresis in some sera treated with low concentrations of cyanate. Measurements of circular dichroism of highly purified carbamylated C3 showed no detectable changes in structure even though most of the functional activity was destroyed. Purified, inactive C3 that was carbamylated with 14C-labeled cyanate was capable of binding to EAC142, but the resulting EAC1423 was weakly positive for immune adherence and negative for agglutination with anti-C3 antiserum. Unlabeled, cell-bound C3b on EAC142 was not susceptible to cyanate action as shown by no loss in immune adherence and positive agglutination with anti-C3 antiserum. The C3b inactivator was more susceptible to cyanate than C3 in a short time period, whereas both were inactivated after 8 hr. Since cyanate is currently being evaluated as a treatment for sickle-cell disease, the inactivation of C3 by the drug is an important consideration for such patients who are already deficient in C3 dependent heat-labile opsonins that aid in host defense.

Anemia, Sickle Cell↗
PubMed1975

Complement-mediated release of histamine from human leukocytes.

Activation of either the alternative or classical pathway of complement generated a factor which induced release of histamine from both non-allergic and allergic human basophils. This factor probably is derived from the complement system since 1) its formation was associated with loss of C3 activity in human serum, 2) chemotactic factor, probably also a complement product, was generated simultaneously, 3) heat inactivation blocked its formation, 4) anti-C3 and anti-C5 blocked formation of the factor, and finally 5) anti-C5 inhibited the activity of the factor once it had been formed. It appears that both complement-mediated and allergen-mediated release of histamine from basophils are secretory, non-cytolytic pathways since both were maximal at 37 degrees C, required the presence of divalent cations, and were inhibited by theophylline. One consistent difference between these two mechanisms was noted: complement-initiated release of histamine occurred more quickly.

Animals↗
PubMed1975

The influence of chrysotherapy on serum protein and immunoglobulin levels, rheumatoid factor, and antiepithelial antibody titers.

Serum protein and immunoglobulin concentrations, rheumatoid factor (RF) titers, and erythrocyte sedimentation rates (ESR) from 18 patients with active rheumatoid arthritis (RA) who were being treated with gold sodium thiomalate (Myochrysine) and monitored clinically were measured serially. Serum antiepithelial antibody (AEA) titers from 10 patients with pemphigus who were similarly treated were measured at frequent intervals. Statistically significant reductions of alpha2, gamma, and total globulins, IgG, IgA, and IgM, ESR, and RF, and AEA titers were found after 3 to 6 months of gold treatment. Serum albumin levels rose significantly, but alpha1, beta-globulin, and total protein did not change. A temporal relationship between the alteration of these serological tests and the clinical response to treatment was noted, but the magnitude of protein change did not correlate with the degree of clinical improvement within a given patient. These findings indicate that gold treatment influences serum protein and antibody concentrations in two diseases having diverse target organs and different etiologies. The question of whether gold compounds exert an immunosuppressive action, or whether the serologic changes are a secondary phenomenon reflecting amelioration of disease activity, is unresolved.

Aged↗
PubMed1974

Elastase of Pseudomonas aeruginosa: inactivation of complement components and complement-derived chemotactic and phagocytic factors.

A purified elastase from Pseudomonas aeruginosa was highly destructive for fluid-phase and cell-bound C1 and C3 and fluid-phase C5, C8, and C9. Inactivation of C4, C2, C6, and C7 by the enzyme varied from 0 to 67%. Low concentrations of elastase generated, then inactivated, a chemotactic factor from human C5 but not from C3. Higher enzyme concentrations inactivated the C5 chemotactic activity at a faster rate. Elastase treatment of sensitized pseudomonads containing cell-bound C3 reduced the phagocytic indexes of polymorphonuclear leukocytes. The data support the proposed chemopathogenic role of the elastase in generation of the characteristic non-inflammatory Pseudomonas vasculitis.

Animals↗
PubMedDate not supplied

Modified immunoassays for polyether toxins: implications of biological matrixes, metabolic states, and epitope recognition.

Polyether marine toxins are responsible for the seafood intoxication phenomena known as neurotoxic shellfish poisoning (due to brevetoxins), ciguatera (due to ciguatoxin), and diarrheic shellfish poisoning (due to okadaic acid). Using traditional techniques of hapten (pure toxin) conjugation to protein to create complete antigen, animal immunization and antibody isolation, and specific antibody subpopulation purification, discriminating antibodies have been isolated that detect brevetoxins and ciguatoxin, but not okadaic acid, in a dose-dependent fashion. Using microorganic chemistry and purified toxins, a unique set of tools has been created for the study of polyether ladder toxin accumulation; depuration; and specific site localization in tissues, food sources, and clinical samples. Developed test protocols can detect toxin in dinoflagellate cells, in extracts from food sources, in seawater and culture media, and in human serum samples. Enzyme-linked immunosorbent assay protocols developed for eventual collaborative testing have been successful in limited applications within the laboratory (correlation coefficient of 0.92 excluding 2 outliers), and alternative formats are being developed to optimize the basic test for use in research laboratories, regulatory laboratories, and field inspections.

Antibodies↗