Prophylactic therapy with OKT3 does not affect donor specific reactivity of peripheral blood lymphocytes from heart transplant recipients.

To avoid the nephrotoxic effect of high-dose cyclosporin A (CsA) immediately posttransplant, heart transplant recipients received as prophylactic therapy intravenous OKT3 for seven days instead of intravenous CsA. Patients receiving OKT3 were compared with patients receiving CsA with respect to specific proliferation and cytotoxicity of their peripheral blood mononuclear cells (PMNC) against donor antigens, at different times within three months post-transplant. No effect of the initial immunosuppressive therapy was observed on these parameters. Acute rejection did not induce a consistent effect on the relative proliferation. PMNC from patients who experienced one or more rejection episodes showed a decrease in donor specific relative proliferative response in time after transplantation, while nonrejectors did not or only slightly, independent of the initial immunosuppressive protocol. Within the group of patients not receiving OKT3, this effect of rejection reached significance. In conclusion, no effect of prophylactic OKT3 therapy compared with prophylactic CsA therapy was observed on donor reactivity of PMNC in vitro during the subsequent three to four months post-transplant.

Factors affecting short- and long-term outcome of a short therapeutic trial with cisapride in dyspeptic patients.

In a Dutch general practice trial conducted in 599 patients with symptoms of dyspepsia, the response to 5 mg cisapride three times daily was rated excellent or good in 61% of patients at week 2. On increasing the dose to 10 mg three times daily in 132 patients with poor to moderate response, the result at the end of treatment was rated as good or excellent in 45% of these patients, and the mean symptom score further decreased significantly (p < 0.05). The longer the pretreatment duration of dyspeptic symptoms, the lower was the overall response rate to cisapride short-term therapy (80% in patients with complaints < 3 months versus 50% in those with complaints > 4 years). Cisapride also proved effective in patients previously treated with prokinetic agents (72% response rate), antacids (66%) and H2-receptor antagonists (48%). On long-term follow-up, dyspepsia relapse rates among the total patient population (n = 357) and the patient sample fully 'cured' after 4 weeks of cisapride (n = 226) were respectively 30% and 27% after 6 months. Factors affecting recurrence of dyspeptic symptoms included age, duration of symptoms prior to trial entry and mean symptom score at end of the treatment study, but not the symptom severity prior to treatment. Relapsing patients presented mainly with the same symptom profile as at the first study, and the majority (88%) responded well to repeated treatment with cisapride. In conclusion, most patients responded well to a short therapeutic trial with cisapride and remained free from relapse in the subsequent 6 months. Repeated treatment in patients with recurrent symptoms appeared to be successful.

Traumatic bilateral renal artery thrombosis diagnosed by computed tomography with successful revascularization: case report.

Traumatic bilateral renal artery thrombosis is a rare injury. We found 15 cases previously reported. An additional case report of a 54-year-old man is presented with a review of the literature. The diagnosis was made by computed tomography and confirmed by angiography. Successful revascularization was performed. A high index of suspicion, early diagnosis, and prompt revascularization are essential in obtaining optimal results without hypertension or permanent impairment of renal function.

Monitoring of cardiac graft recipients: comparison of in vivo activated, committed T lymphocytes in peripheral blood and in the graft.

The proliferative and cytotoxic capacity of peripheral blood lymphocytes (PBL) and the cytotoxic activity of lymphocytes propagated from endomyocardial biopsies (EMB) towards donor cells was used to identify in vivo activated, committed T cells. A series of 39 PBL samples and 38 EMB simultaneously taken from 20 patients after heart transplantation was cultured in interleukin 2 (IL-2) conditioned medium. The cytotoxic capacity of these cultures against donor cells was tested in a 4-h chromium-51 release assay. From a comparable patient group, 224 samples were evaluated for donor reactivity by a primed lymphocyte test (PLT). Analysis showed that PBL cultures hardly ever contained committed cytotoxic T lymphocytes (cCTL, 2/39) or committed proliferative T lymphocytes (cPTL, 1/224). In contrast, significantly more EMB cultures (17/38, P < 0.001, chi2 test) demonstrated donor-directed cytotoxicity. This was especially found during rejection (11/17 vs 6/21 without rejection, P = 0.05). These results show that after heart transplantation, committed cells are mainly found in the graft.

Vitrification of human islets of Langerhans.

Cryopreservation of human islets of Langerhans by vitrification was studied. Isolated islets were divided into four groups: (1) control islets which were cultured for 6 days, (2) islets which were vitrified after 2 days of culture, (3) control islets which were cultured for 10-13 days, and (4) islets which were vitrified after 6-9 days of culture. After warming, islets from groups 2 and 4 were cultured for 4 days. The thus treated islets were investigated with respect to insulin secretion in the presence of 2.5 or 25 mM glucose, capacity to survive during postwarming culture, and morphology. The insulin secretion in islets from all groups could be stimulated by an increase of the concentration of glucose from 2.5 to 25 mM. No significant differences were observed between the insulin secretions of the vitrified and control islets or between the islets vitrified after 2 and 6-9 days of culture. It is concluded that human islets of Langerhans cryopreserved by vitrification are functional in vitro.

Vitrification of mouse islets of Langerhans: comparison with a more conventional freezing method.

The possibility of cryopreservation of islets of Langerhans by vitrification using a mixture of cryoprotectants was investigated and the results were compared with a more conventional freezing method using Me2SO as cryoprotectant. Isolated mouse islets were divided into three groups: (1) control islets cultured for 6 days, (2) islets which were cryopreserved by vitrification after 2 days of culture, and (3) islets frozen in 1.5 M Me2SO after 2 days of culture. After warming, islets from groups 2 and 3 were cultured for 4 days. The thus treated islets were investigated with respect to insulin secretion in the presence of 2.5 or 25 mM glucose, survival during postwarming culture, morphology, and capability to reverse streptozotocin-induced diabetes. The insulin secretion in islets from all groups could be stimulated by a factor 5 or more by an increase in the concentration of glucose from 2.5 to 25 mM. The secretion of insulin in the presence of 2.5 mM glucose was similar in all groups of islets. The secretion of insulin in the presence of 25 mM glucose was slightly but not significantly lower in the cryopreserved islets than in the control noncryopreserved islets. The survival of islets during postwarming culture was comparable after cryopreservation with both methods, and islets from both groups could lower serum glucose in streptozotocin diabetic mice. We conclude that islets cryopreserved by the vitrification method are functional in vitro and in vivo. This method is quick, simple, and cheap because the use of complicated freezing equipment is avoided.

Cryopreservation of mouse, monkey and human islets of Langerhans for transplantation purposes.

Transplantation of islets of Langerhans is a possible future therapy for insulin-dependent diabetes mellitus. In contrast to total pancreas, isolated islets of Langerhans can be treated prior to transplantation to reduce their immunogenicity. Thus the success rate in allotransplantation of islets can be increased. The isolation of large amounts of islets from human pancreas is still a problem and islets from different donors have to be collected and stored by cryopreservation. In this paper we describe the methods used in our laboratory to isolate islets of Langerhans from rodent, monkey and human pancreas. The results are presented of successful cryopreservation of these islets. Firstly, by a more conventional freezing method using dimethylsulfoxide as cryoprotectant. Secondly, by vitrification using a mixture of cryoprotectants. The latter method has not been used previously for cryopreservation of islets. The integrity of the islets before and after freezing was tested in vitro and, for mice, in vivo.