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Biomedical subjects

S H Leech

Publications and source records attributed to S H Leech.

43 records · Page 3Linked to original sources
PubMed1976

Effect of prior sensitization with hapten on the antibovine IgG antibody response to hapten-conjugated tolerogen of mice tolerized by low doses of bovine IgG.

Mice tolerized by low doses of bovine IgG (BGG), immunized with arsanilated (ARS) conjugates and challenged with ARS-BGG show an augmented anti-BGG antibody response compared with controls immunized with nonconjugated carrier. Conditions optimal for generating hapten help are explored and suggest that the phenomenon is mediated by hapten-specific helper T cells. During exploration of these conditions it became apparent that the response was suppression rather than augmentation with ARS, under certain circumstances, and with 2,4-dinitrophenyl, 4-hydroxy-5-iodo-3-nitro-phenylacetyl (NIP) and sulfanilic acid, under all conditions tested. Especially important in determining the outcome of the interaction was the type of adjuvant used for hapten priming. The significance of these observations is discussed in relationship to the balance between negative and positive cooperation.

Animals↗
PubMedDate not supplied

Management of the sensitized cardiac recipient: the use of plasmapheresis and intravenous immunoglobulin.

Previously, we reported that the combination of plasmapheresis (PP) and intravenous immunoglobulin (IVIg) allow sensitized patients to undergo orthotopic heart transplantation (OHT), even across a positive crossmatch. In the current study, the effect of that combination, PP+IVIg, on survival of a larger group of such recipients is investigated. The latter group (I) consisted of 35 sensitized patients who received PP+IVIG together with standard immunosuppressive drugs. Rejection was seen in 11 patients, findings strongly suggestive of a vascular (humoral) being identified in five of those cases. Four deaths occurred, two of them in the immediate post-operative period, one after almost six months, and one after almost two yr post-OHT. Follow-up range 4.5 months to 7.8 yr post-OHT (average=1.1 yr). Patient survival was analyzed after generation of a Kaplan-Meier plot. Comparison with a control OHT group (II) given standard immunosuppressive drugs only (N=276) showed enhanced survival of group I (p=0.0414 by log-rank test). We conclude that the combination of PP and IVIG (i) is associated with declines in T- and B-percent-reactive antibody and in crossmatch positivity, and (ii) is very useful in the management of the sensitized cardiac patient undergoing OHT, often allowing a successful outcome to transplantation in the face of a positive crossmatch.

Biopsy↗
PubMedDate not supplied

Augmentation of the antibody response by hapten help. II. Determination by many genes outside the MHC.

The purpose of the present work was to characterize the immune response (Ir) genes that influence augmentation of the antibody response by help with the hapten azobenzene-arsonate (ABA). Hapten help was measured as the augmentation in the plaque-forming cell (PFC) response to bovine gamma globulin (BGG) after priming mice with ABA conjugated to ovalbumin (OVA) and challenging subsequently with ABA-BGG. The first approach involved inbred mouse strains that were matched for H-2 but differed in their non-H-2 genetic backgrounds. B10.D2 mice were low responders even though they shared the H-2d haplotype with BALB/c and DBA/2 mice, which were high responders. C57BL/10 mice were high responders even though they shared the H-2b haplotype with C57BL/6, C3H.SW, and A.BY mice, all of which were strains that were low responders. The second approach was to identify any segregation of H-2 with the gene(s) encoding susceptibility to hapten help in the backcross generation. (BALB/c X C57BL/6) F1 hybrids were backcrossed to C57BL/6. The results showed no association with the major histocompatibility complex (MHC).

Animals↗
PubMedDate not supplied

Steroid treatment for routine immunosuppression in cadaver renal transplantation. A survey of hospitals.

A review of data from 22 hospitals in the U.S. and Canada, comprised of information on 1700 kidney transplant patients, shows a consistent pattern with respect to usage of steroids both as routine treatment and for rejection episodes. High doses are associated with greater patient mortality. Graft survival is also adversely affected by very high doses, but only in the immediate post-transplant period. Our data suggest that for optimal graft and patient survival the dosage of steroids should be less than 150 mg/day of methylprednisolone on days 1-3, less than 50 mg/day of prednisone on days 4-21, less than 30 mg/day on days 22-30, and less than 20 mg/day between one mo and one yr.

Cadaver↗