Evidence that tolerance to cultured thyroid allografts is an active immunological process. Protection of third-party grafts bearing new antigens when associated with tolerogenic antigens.

We studied the tolerance phenomenon that develops in long-term recipients of cultured thyroid allografts. Allogeneic mouse thyroids were cultured under hyperbaric oxygen or acidic conditions and then transplanted beneath the kidney capsule of C57BL/6 recipients. Donors differed from the recipients in minor antigens alone, major histocompatibility complex antigens alone, or both. At 35-77 weeks after the first cultured graft, recipients received two more cultured grafts under the capsule of the opposite kidney and were immunized with donor spleen cells (SC). At 5 weeks after the second transplantation, we observed that whereas second grafts carrying new antigens alone were rejected, second grafts carrying new antigens in association with antigens in the first graft were significantly protected. In another set of experiments, normal mice became tolerant to cultured allografts after 2 weeks in parabiosis with tolerant individuals. Tolerant mice showed reduced specific in vivo and in vitro cytotoxic T lymphocyte responses. However, the frequency of CTL precursors of tolerant mice was the same as in normal mice. The reduced in vitro CTL responses were restored to normal levels by the addition of a lymphokine rich medium. Also, we observed that the injection of specifically activated immune SC caused the rejection of cultured allografts in normal but not in tolerant recipients. We conclude that the tolerance that develops in recipients of cultured allografts is an active immunological process that affects the activation and effector function of CTL.     

Role of calcium and cAMP in the regulation of rat submandibular mucin secretion

The role of cellular adenosine 3',5'-cyclic monophosphate (cAMP) and calcium in the secretion of [14C]glucosamine-labeled mucins by rat submandibular acinar cells was studied. cAMP appeared to be involved, since 1-methyl-3-isobutylxanthine potentiated the secretory response and cellular cAMP levels increased dramatically following adrenergic stimulation. Furthermore, cAMP analogues were able to elicit a secretory response in the absence of beta-adrenergic receptor activation. Cellular calcium was required for mucin secretion at the level of cAMP action; depletion of cellular calcium by pretreatment with EGTA inhibited the secretory response to both adrenergic stimulation and exogenous cAMP addition, but pretreatment with EGTA did not alter the rise in cellular cAMP induced by norepinephrine. Extracellular calcium was not required to elicit mucin secretion, nor could secretion be elicited by means of the calcium ionophore A23187 alone. However, extracellular calcium may have an important biological role in mucin secretion, since cholinergic receptor activation and alpha-adrenergic receptor activation in conjunction with beta-adrenergic receptor activation potentiated mucin release. In addition, the calcium ionophore A23187 potentiated mucin release following cAMP analogue addition.     

Modulation of tissue immunogenicity by organ culture. Comparison of adult islets and fetal pancreas

Uncultured mouse islet allografts (BALB/c to CBA) are rejected 2 to 4 weeks after transplantation. Allografts, cultured in 95% O2 and 5% CO2 for 7 days before transplantation, show no sign of rejection up to 3 months post-transplantation. However, the cultured allografts are rejected if the CBA recipient is given an i.v. injection of 10(5) peritoneal cells at the time of transplantation. Organ culture of BALB/c fetal pancreas (16 to 17 days gestation) under the same conditions failed to prevent allograft rejection. The immunogenicity of fetal pancreas is reduced if this tissue is cultured in 95% O2 and 5% CO2 for 17 days before transplantation.     

非穿透性小梁切除术联合人羊膜植入临床观察

目的：观察非穿透性小梁切除术联合人羊膜植入的临床效果。方法：对18例（30眼）中、晚期开角型青光眼进行非穿透性小梁切除术联合人羊膜植入，术后观察视力、视野、眼压及滤过泡形成情况。结果：术后随访3－9月，视力、视野稳定，眼压≤20mmHg(1mmHg=0.133kPa)，滤过泡形成良好，并发症少。结论：非穿透性小梁切除术 联合人羊膜植入治疗开角型青光眼，能有效降低眼压，形成功能性滤过泡和并发症少等优点，是治疗开角型青光眼较理想的方法。