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P Monnot

Publications and source records attributed to P Monnot.

18 recordsLinked to original sources
PubMed1996

[Grafting of the cornea and implants sutured to the sclera or anterior chamber. Comparative study on graft survival and endothelial cell loss].

PURPOSE: We studied the percentage of graft survival and endothelial cell loss after penetrating keratoplasty with scleral sutured posterior chamber lens compared with secondary anterior chamber lens. METHODS: The study concerned 46 patients divided into two groups: group I: 26 cases with scleral sutured posterior chamber lens; group II: 20 cases with anterior chamber lens. The postoperative Kaplan-Meir curve survival was established and cell loss assessed between graft cell density and postoperative cell density according to Sperling's method. RESULTS: After one year, cell loss was less important in group I (69.23%) than in group II (95%). However, after the first postoperative year, this difference decreases and becomes very slight at the fourth postoperative year. The percentage of cell loss during the first year is 44.6% in group I and is 41.8% in group II. After the first year, the percentage of annual cell loss is 3% in group I and ranges between 6 and 8% in group II. CONCLUSIONS: Except for age, there was no significant difference between the two groups preoperatively. This, it seems that the high postoperative intra-ocular pressure, more frequent in group I, was a poor prognosis factor for graft survival. After one year, results were similar in the two groups for graft survival, but in group I, the annual percentage cell loss was lower.

Adult↗
PubMed1987

In vitro immunomodulatory effects of placental substances on preparatory MLR and resulting modifications of lymphocyte reactivities.

The immunomodulatory effects of murine placental extracts (PE) were studied in vitro using mixed lymphocyte culture (MLC) and resulting cell-mediated lympholysis (CML). The results showed that preparative cultures in the presence of PE syngeneic to the responding cells led to a low secondary MLR response with a concomitant generation of suppressor cells. At the efferent phase, cells from the same preparative culture showed a weaker cytotoxic activity than controls cultured in the absence of extract. Furthermore, the induction of regulatory cells able to inhibit CTL in vitro activity was also observed. The active substances can be found in the 30% ammonium sulphate precipitate as well as in some gel filtration fractions showing several main bands from 115 to 43 kDa in SDS-PAGE.

Animals↗
PubMed1986

Maternal alloimmune reactions towards the murine conceptus and graft-versus-host reaction (GVHR). I. Priming for anti-paternal GVHR by gestation.

In the H-2 compatible (but minor loci-incompatible) BALB/c-DBA/2 strain combination (both H-2d), intravenous injection of 1.3 X 10(7) BALB/c spleen cells from virgin females into DBA/2 newborn mice less than 18 h old does not result in a significant lethal graft-versus-host reaction (GVHR). A strong GVHR (79% lethal) is induced if the BALB/c donors have been preimmunized to DBA/2. Spleen cells from BALB/c mice pregnant by DBA/2 males are also able to induce a significant, but weaker, GVHR (16% lethal) indicating a cellular priming to paternal antigens by gestation. A significant difference exists between anti-DBA/2 GVH reactivity of spleen cells from primiparous (22% lethal) and multiparous (9% lethal) allopregnant BALB/c mice, indicating that the allogeneic boosters of successive allogestations act more on the target-protective side of immunity than on the target-aggressive one. Sera from allopregnant mice (BALB/c X DBA/2) inhibit the GVHR induced by their own cells, while sera from isopregnant ones (BALB/c X BALB/c) have no effect. Thymectomy performed at 6-wk of age, six weeks before gestation did not significantly modify the maternal reactivity. A similar priming by allogestation in the same strain combination was found for local GVHR (induced in adult F1 hybrids) resulting in higher (+132%, P less than 0.005) stimulation indices and seen to be specific for the paternal strain, the indices induced by the same cells being lower (-35%, P less than 0.05) compared to that induced by cells from virgin BALB/c, when injected into irrelevant F1 hybrids (BALB/c X CBA).

Animals↗
PubMed1985

Evolution of alloantibodies and suppressor cells in allografted mice treated for passive enhancement.

The kinetics and quality of the alloimmune reaction were studied in CBA (H-2k) mice treated for passive enhancement of tumor allografts (Sa 1 indigenous of A/J (H-2a or H-2k/d) mice). Serum samples of treated animals were tested for their biological properties relevant to different antibody isotypes in vitro (hemagglutination, complement-dependent cytotoxicity, and anaphylaxis, i.e., mast cell degranulation involving all main Ig isotypes; IgM, IgG2, and IgG1, IgE, respectively) as well as in vivo (allograft enhancement). Spleen cells from these treated animals were examined for their capacity to interfere with the rejection of tumor allografts by adoptive transfers into syngeneic recipients. In vitro, 51Cr release cytolysis assays were performed in order to test their cytolytic and regulatory activities in comparison to rejecting control animals. It has been shown that: grafted mice, pretreated for passive enhancement, kept their grafts longer and synthetized anaphylactic antibodies (mainly IgG1) earlier and at higher titers than normal serum controls, which rejected the same Sa 1 allografts. Mice with enhanced tumors synthetized cytotoxic antibodies (mainly IgG2) later than rejecting controls. Serum samples from treated and control animals, harvested 10 days (early sera) and 30 days (late sera) after grafting, were injected with a "normal dose" (0.2 ml) and a "high" dose (0.4 ml) to new CBA recipients grafted with Sa 1. Early immune sera were only enhancing at high doses when derived from animals previously treated for enhancement (at the low dose both immune sera were enhancing). Late sera, presenting both complement-fixing, cytotoxic (predominantly IgG2), and IgG1 anaphylactic alloantibodies in the two groups, induced enhancement in all cases, but more strongly when derived from the group treated for Sa 1 enhancement. Adoptive transfer of spleen cells from animals treated for passive enhancement were able either to inhibit the accelerated rejection (Day 10) or to promote enhancement of Sa 1 allogeneic cells (Day 30) while similar cells taken (Day 10 and Day 30) from control graft-rejecting mice transferred accelerated rejection. Among the transferred T-cell sub-populations, the suppressive effect was mediated by Lyt 2 T cells. In vitro, these spleen cells showed a weaker cytolytic activity than those of allograft-rejecting mice. Moreover, they were able to regulate the cytolytic activity of cytotoxic effector cells from specifically immunized CBA mice.

Animals↗
PubMed1980

Regulatory mechanisms of cell-mediated immunity in allogeneic pregnancy.

The transfer of cells from allopregnant animals to syngeneic receivers allografted with paternal strain tumor leads to mild but significant enhancement. The effect can be defined as T cell mediated. Cells from allopregnant animals can suppress a mixed lymphocyte reaction (MLR) of maternal responders against paternal stimulators. The effect relies upon a THY 1+, Ly 2+, Ia+ cell. Cell-mediated lympholysis (CML) assay could also be suppressed by cells from allopregnant animals. Placental products are capable of interfering with allograft rejection in vivo. They can block MLR in vitro, and seem to act in part via the induction of suppressor cells. The respective roles of these depressive components, together with enhancing antibodies, is discussed.

Animals↗
PubMed1976

Competitive proliferation in the hematopoietic tissues of irradiated hybrid mice engrafted with parental bone marrow and spleen.

The kinetics of growth and differentiation of hematopoietic stem cells differ markedly according to their origin. A study of the ability of CFU from bone marrow (BM) or spleen to repopulate hemopoietic organs has been carried out in lethally irradiated mice restored with BM cells admixed with spleen cells bearing different chromosomal markers. Hemopoietic cells originating from AKR (40 acrocentrics) and AKR/T1ALD (36 acrocentrics + 2 metacentrics) mice were engrafted into lethally irradiated (AKR X AKR/T1ALD)F1 or (C3H X AKR/T1ALD)F1 hybrid recipients. Within 10 days, the BM-derived elements outnumbered the spleen-derived population in BM and spleen. This held even when the number of injected spleen-CFU was twice that of BM-CFU. This difference of growth rate subsided within 20 days. The first cells to reappear in the thymus bore the recipient karyotype (endoregeneration); they were later replaced by BM-derived elements but spleen-derived cells were never present in thymus in the case of competitive engraftment. In contrast, the lymph node cells bore the BM karyotype as well as the spleen karyotype. Injecting the spleen cells 3 days prior to the BM cells partially counterbalanced the over-growth of the BM-derived elements in the BM and spleen but did not affect the thymic repopulation which remained strictly derived from BM-CFU. When mice were injected only with BM-CFU or only with spleen-CFU, BM-derived cells were found in the thymus as early as 10-12 days after engraftment whereas the spleen-derived cells did not appear in the thymus until days 18-20.

Animals↗
PubMedDate not supplied

Systemic active suppression is not necessary for successful allopregnancy.

To investigate the role of systemic suppression during allopregnancy, CBA/J female mice were immunised against H-2d prior to mating. Cytotoxic T lymphocyte (CTL) activity was tested at days 14-16 of pregnancy. A reduction of CTL activity was observed only in multiparous animals. Although a nonspecific suppression was detected in isopregnancy, suppression was more marked in allopregnancy. Conversely, the CTL activity observed in the spleen during the first pregnancy (iso or allo) was always significant in mice presensitized with 2 or 3 alloimmunizations prior to pregnancy. Such animals have in vivo effector cells, since allografts of Sarcoma Sa1 were rejected in secondary fashion in alloimmunized mice, while the fetus remained unharmed. These observations demonstrate that allospecific anti-MHC CTLs are specifically impaired in multiple allopregnancy, but also tend to rule out theories postulating that systemic suppression of CTL generation and function is required for successful allopregnancy.

Animals↗