Macrophages as targets for inhibition by cyclosporine

In order to understand the mechanism of immunosuppression by cyclosporine, its effects on macrophage-mediated antigen-specific T cell activation (IL-2 production) were studied in vitro. While cyclosporine (CsA) present during the macrophage-T cell coculture inhibited antigen presentation effectively, pretreatment (2 hr) of macrophages with the drug also caused marked inhibition regardless of the antigen concentration and order of drug/antigen addition. Pretreatment of T cells caused only modest inhibition. With macrophage pretreatment, the structural analog cyclosporine-G had the same inhibitory activity as cyclosporine (cyclosporine-A), whereas dihydro-cyclosporine-D and cyclosporine-H were inactive. Cyclosporine demonstrated saturable binding to macrophages suggesting the existence of CsA-binding sites. A 50% inhibition of IL-2 production was achieved with 10(-6) M CsA and 60-70% of the binding sites were occupied at this concentration. CsA-treated macrophages did not release inhibitory material and the drug did not appear to be transferred from the macrophages to the T cells during the coculture. Although antigen-specific T cells could bind to drug-treated macrophages, they did not produce IL-2. Collectively, these results suggest that CsA has a direct effect on macrophages that subsequently interferes with IL-2 production at a stage following T cell antigen recognition.     

Central muscarinic effects of physostigmine on mood,cardiovascular function,pituitary and adrenal neuroendocrine release

The mechanism by which physostigmine exerts its behavioral, neuroendocrine and cardiovascular effects was explored in two separate experiments. In the first, the centrally-acting cholinesterase inhibitor physostigmine was compared with the non-centrally-acting agent neostigmine. In contrast to physostigmine, neostigmine caused no effects. In the second experiment, pretreatment with scopolamine, in contrast to methscopolamine, attenuated physostigmine's effects. The results suggest that physostigmine exerts its effects via a central muscarinic mechanism.     

The effect of hemorrhage and resuscitation on serum levels of immunoreactive atrial natriuretic factor.

To determine if atrial natriuretic factor (ANF) might have a role in blood volume regulation during hypovolemia, the serum level was measured before and after hemorrhage and resuscitation (RESUS) in a porcine shock model. Hemorrhage of 40% of the blood volume produced significant (p less than 0.01) decreases in mean arterial pressure, central venous pressure, and cardiac output and a significant increase in heart rate (HR), plasma renin activity, and catecholamines (p less than 0.01). Hemorrhage was also associated with a significant increase in ANF (p less than 0.05). All parameters except HR returned to baseline values with RESUS. The rise in ANF associated with moderate hemorrhage was unexpected, but may have been due to the profound tachycardia or decreased degradation during shock. Sodium excretion and urine flow increased significantly with RESUS without an associated increase in ANF, suggesting that ANF may not be involved in the early phase of postresuscitation diuresis.     

Enhanced suppression of 1,25(OH)2D3 and intact parathyroid hormone in Graves' disease as compared to toxic nodular goiter

Summary 1,25(OH)₂D₃, 25OHD₃, and intact parathyroid hormone, as well as various parameters of calcium-phosphorus metabolism were measured in 38 patients with Graves' disease (GD) and in 24 patients with toxic nodular goiter (TNG). Plasma 1,25(OH)₂D₃ levels were lower in GD patients (82 ±29 pmol/liter) than in those with TNG (155±32 pmol/liter) (P<0.0005). The mean value of 1,25(OH)₂D₃ in 45 controls was intermediate between the two groups of patients (140±41) and the difference was statistically significant. GD patients before and after treatment had higher alkaline phosphatase (P<0.05), lower intact parathyroid hormone (PTH) (P<0.05), and lower 1,25(OH)₂D₃ levels (P<0.0005 in the hyperthyroid andP<0.01 in the euthyroid state) than TNG patients. We conclude that increased skeletal calcium resorption is due to elevated levels of T₃ causing suppression of 1,25(OH)₂D₃ production and of PTH levels in both groups of patients albeit of different degrees. Furthermore, we postulate that the profound suppression of 1,25(OH)₂D₃ in GD is secondary to an immune-mediated phenomenon.     

Flow cytometric analysis of lymphocyte phenotypes in AIDS using monoclonal antibodies and simultaneous dual immunofluorescence

Simultaneous dual immunofluorescence and flow cytometry was used to study sixteen lymphocyte phenotypes in 209 men including: healthy homosexuals, lymphadenopathy patients (LAN), and AIDS patients. Significant differences between the distribution of lymphocytes in healthy homosexuals and healthy heterosexuals were decreased percentages of helper/inducer T cells (Leu 3), increased cytotoxic/suppressor T cells (Leu 2), and consequently a decreased Leu 3/Leu 2 ratio. The increased Leu 2 cells were identified as functionally cytotoxic subset Leu 2+ 15- phenotype rather than suppressor cells which are Leu 15+. Leu 2 and Leu 3 bearing cells exhibited an excess of membrane-bound immunoglobulins which were easily elutable at 37 degrees C. An increased percentage of an HLA-DR framework determinant bearing T cells were also detected. Within the NK cell family, Leu 7 cells were moderately increased and the functionally unidentified Leu 2+ 7+ population was strikingly elevated. LAN or AIDS patients were compared to healthy homosexual controls. Lower percentages of Leu 3 cells and higher percentages of Leu 2 cells were evident in LAN patients. These subsets were similar in LAN and AIDS patients. The increase in Leu 2+ cells was due to the Leu 2+ 15- cytotoxic subset. Fewer T cells had immunoglobulin in LAN and AIDS. A definite increase in Leu 2+ DR+ cells but not Leu 3+ DR+ cells occurred in AIDS compared to LAN or healthy controls. NK cell changes already present in healthy homosexuals persisted in LAN and AIDS patients. No differences in the distribution of B cells was detected in any intergroup comparisons. Changes in monocytes or pan-T cells were relatively insensitive measures of immunologic alterations among any of the groups. These results indicate many of the changes in lymphocyte subsets seen in AIDS and LAN subjects are already present in a carefully screened population of healthy homosexuals in San Francisco. Many of the changes in Leu 2 and NK family of cells suggest a possible adaptive response to viral or neoplastic challenge. Whether these interesting phenotypic alterations relate to functional changes in response to such challenge of the identified subsets waits further investigation.     

Advanced combined intra-uterine and ovarian gestations: case report

Combined intra-uterine and ectopic gestations are uncommon. Heterotopic gestations in which the ectopic pregnancy is located in the ovary are exceptional. We are reporting a 22 week heterotopic gestation with two live fetuses, one fetus was developing in the uterus and one in the ovary. Surgical excision of the ovarian pregnancy was conducted without disturbing the intra-uterine live fetus who was ultimately delivered uneventfully at term.