Inhibition of vessel allograft rejection by endothelial removal. Morphologic and ultrastructural changes.

The vascular endothelium plays an important and complex role in vascular allograft rejection. Antigens expressed by the endothelium can act to promote and be the target of rejection reactions, which often lead to thrombosis and ischemic necrosis of the allograft. In this study, segments of femoral artery and femoral vein with or without endothelium were grafted between allogenic or autologous control rats. Immunocompetent Lewis (RT1(1] recipient rats were randomly selected for groups (N = 14 for each) receiving the following: ACI- (RT1a) allografts with intact endothelium, allografts with endothelium removed before operation, autografts with endothelium, and autografts with endothelium removed. Rejection was assessed by graft patency as well as morphologic and ultrastructural changes. At 5 days, the allografts with intact endothelium were totally occluded, whereas allografts without endothelium remained patent, as did autologous control grafts with or without endothelium. Two additional groups (N = 14 each) receiving the de-endothelialized allografts or autografts were examined at 120 days after operation, revealing that grafts in both groups were still patent and had been re-endothelialized. These findings indicate that physical removal of vascular endothelium may depress vessel allograft rejection without immunosuppressive therapy.     

Management of filamentary keratitis associated with aqueous-deficient dry eye.

PURPOSE: To review the incidence, underlying pathophysiology, and clinical features of filamentary keratitis and to identify evidence-based best-practice strategies for managing filamentary keratitis. METHODS: A comprehensive review of published literature was undertaken. Recommendations for best-practice management strategies were based on the available evidence. Three cases are presented to illustrate the clinical findings and management of patients with chronic filamentary keratitis. RESULTS: Although the evidence base is limited by the absence of well-designed studies, current evidence indicates the following: (1) Aqueous-deficient dry eye (keratoconjunctivitis sicca) is the most common ocular condition associated with filamentary keratitis. (2) Current best-practice management of filamentary keratitis involves treating the underlying dry eye and specific treatments for the corneal filaments. Proposed treatments include nonpreserved lubricants, topical steroidal and nonsteroidal anti-inflammatory agents, and punctal plugs for aqueous-deficient dry eye as well as mechanical removal of filaments, hypertonic saline, mucolytic agents, and bandage contact lenses for the filaments. (3) Filamentary keratitis can be induced or exacerbated by contact lens wear and ocular surgical procedures such as cataract surgery and corneal graft surgery. Pre- and postoperative ocular surface management strategies should be considered in the surgical planning of patients with, or who are susceptible to, filamentary keratitis. Filamentary keratitis can also be induced and/or exacerbated by chronic use of ocular and/or systemic medications, and alternate medications or additional measures to manage the tear film and ocular surface may be required in these cases. CONCLUSIONS: Filamentary keratitis can be a chronic, recurrent, and debilitating condition. With a systemic approach to diagnosis and management, the condition can be effectively controlled and the incidence and severity of recurrences minimized.     

Benign intracranial hypertension and recombinant growth hormone therapy in Australia and New Zealand

Benign intracranial hypertension (BIH) is reported in three children from Australia and one from New Zealand, who were being treated with recombinant human growth hormone (rhGH). Three males and one female, aged between 10.5 and 14.2 y, developed intracranial hypertension within 2 weeks to 3 months of starting treatment. A national database, OZGROW, has been prospectively collecting data on all 3332 children treated with rhGH in Australia and New Zealand from January 1986 to 1996. The incidence of BIH in children treated with growth hormone (GH) is small, 1.2 per 1000 cases overall, but appears to be greater with biochemical GHD (<10IUml ^-1), i.e. 6.5/1000 (3 in 465 cases), relative risk 18.4, 95% confidence interval 1.9-176.1, than in all other children on the database. The incidence in patients with Turner's syndrome was 2.3/1000 (1 in 428 cases). No cases in patients with partial GHD (10–20 IUml ^-1) or chronic renal failure were identified. Possible causative mechanisms are discussed. The authors'practice is now to start GH replacement at less than the usual recommended dose of 14IUm-² week^-1 in those children considered to be at high risk of developing BIH. Ophthalmological evaluation is recommended for children before and during the first few months following commencement of rhGH therapy and is mandatory in the event of peripheral or facial oedema, persistent headaches, vomiting or visual symptoms. The absence of papilledema does not exclude the diagnosis.     

Multivariate analysis of risk factors in cadaver donor kidney transplantation

Data collected prospectively on 3811 kidney transplants performed between June 1977 and July 1982 with follow-up to July 1984 by the 42 member institutions of the South-Eastern Organ Procurement foundation were analyzed to identify factors associated with graft and patient outcome in patients not receiving cyclosporine. Multivariate Cox regression analysis was used to examine the association and relative risk of 24 variables with three actuarial outcomes: overall graft failure, irreversible rejection, and patient death. Factors having no suggested association with any outcome included: recipient sex, history of pregnancy, blood group, and time on dialysis; organ preservation method, time and source; donor race; crossmatch test sensitivity; and annual center transplant rate. In decreasing order of relative risk, the factors most significantly associated with irreversible rejection were: loss of two or more prior grafts, low HLA-A,B match, lack of pretransplant blood transfusion, high (greater than 60%) pretransplant sensitization to leukocyte (HLA) antigens, and delayed graft function. Splenectomy, insulin-dependent diabetes, and antilymphocyte serum therapy provided the greatest risk of patient death. Factors such as recipient age, race, and native nephrectomy had suggested associations with outcome. By adding each center as a separate covariate in the analysis, other center-dependent factors were quantitated and found in some cases to have a highly significant association with graft and patient outcome. These results provide a basis for evaluating the potential risk of graft loss or patient death for those prospective cadaver kidney transplant recipients not being considered for cyclosporine therapy.     

Amniotic fluid levels of substance P.

The presence of substance P (SP) in the amniotic fluid (AF) from 88 obstetric patients was determined with a radioimmunoassay. AF was collected from each patient in EDTA-coated tubes. Cross-reactivity of anti-SP antibody with methionine, met-enkephalin, leu-enkephalin, beta-endorphin, eledoisen and physalemin was less than 1%. The SP levels during the midtrimester were not significantly lower than those of late gestation. Data on the late-gestation group were evaluated further as per the clinical problem. The only statistically significant finding was between the diabetics with fetal maturity and the non-diabetic group. This preliminary study identified the presence of SP in AF in mid and late gestation.