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.     

Evaluation of tissue response to MTA and Portland cement with iodoform.

OBJECTIVE: The aim of this study was to evaluate the biocompatibility of Portland cement with the addition of iodoform, compared to MTA (ProRoot). STUDY DESIGN: Eighteen Wistar albino rats were divided into 3 groups of 6 animals each. Polyethylene tubes were filled either with freshly mixed MTA or Portland cement mixed with iodoform (20% wt/wt) and implanted subcutaneously. An empty tube served as control. After 7, 30, or 60 days, the implants together with the surrounding tissues were removed in blocks. Sections were evaluated for the presence and thickness of a fibrous capsule, presence of granulation tissue, and the severity of inflammatory response. Data were submitted to nonparametric statistical analysis with individual comparisons between groups at a significance level of P < 0.05. RESULTS: There were no differences between inflammatory responses at 7 and 30 days. After 60 days from surgical removal, there was significantly more tissue reaction to the MTA and Portland cement compared to the control group. CONCLUSION: There were no significant differences regarding inflammatory responses between MTA and Portland cement with iodoform after 7, 30, or 60 days. After 60 days, the fibrous capsule around the Portland cement appeared more organized than tissue surrounding MTA implants. After 60 days, there was still a significantly increased tissue reaction to the 2 cements compared to the empty polyethylene tubes.     

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.     

Treatment of muscle spasticity in patients with cerebral palsy using BTX-A: a pilot study

This study was designed to verify the safety and efficacy of botulinum toxin type A (BTX-A) used as a neuromuscular block on spastic masticatory musculature of children with cerebral palsy. Six patients who had spastic-tetraplegic cerebral-palsy, aged 5 to 20 years were selected. All patients had spasticity of the jaw muscles, bruxism, lower lip trauma, limited mouth opening, and difficulties in cleaning the oral cavity. The patients were sedated under general anesthesia, while the dentist injected the masseter and temporalis muscles bilaterally with 150 and 75 units of BTX-A each. Clinical examinations were conducted at 7, 14, 30, and 90 days after the initial appointment. We found statistically significant decreases in muscle spasticity and bruxism ( p = 0.002), improved inter-incisal opening ( p = 0.002), improved oral hygiene ( p = 0.031), and less lower lip trauma ( p = 0.060) after the neuromuscular blocking.     

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.     

Marked increase of asymmetric dimethylarginine in patients with incipient primary chronic renal disease.

In patients with uremia, increased blood concentrations of the endogenous nitric oxide synthase inhibitor asymmetric dimethylarginine (ADMA) have been linked to the severity of atherosclerosis and to excess cardiovascular mortality. The ADMA levels and several traditional cardiovascular risk factors were assessed in 44 untreated nonsmoking patients with confirmed primary chronic renal disease at different stages of renal disease. True GFR was assessed by means of the inulin-clearance technique. For comparison, nonsmoking subjects matched with respect to age, gender, and body-mass index were examined. Mean plasma ADMA concentration was markedly higher (P < 0.0001) in all patients combined (4.2 +/- 0.9 micromol/L) than in control subjects (n = 16; age 45 +/- 10 yr; serum creatinine 1.0 +/- 0.1 mg/dl; ADMA 1.4 +/- 0.7 micromol/L). However, mean ADMA levels were similar in patients with normal renal function (n = 16; age 41 +/- 9 yr; serum creatinine 1.1 +/- 0.1 mg/dl; GFR 120 +/- 14 ml x min(-1) x 1.73 m2; ADMA 4.0 +/- 0.7 micromol/L), in patients with moderate renal failure (n = 15; 47 +/- 7 yr; 1.8 +/- 0.3 mg/dl; 65 +/- 10 ml x min(-1) x 1.73 m2; 3.8 +/- 0.6 micromol/L) and in patients with advanced renal failure (n = 13; 46 +/- 9 yr; 4.2 +/- 0.9 mg/dl; 25 +/- 4 ml x min(-1) x 1.73 m2; 4.7 +/- 1.2 micromol/L). Furthermore, ADMA levels were increased to the same extent in normotensive (n = 17; 4.0 +/- 0.8 micromol/L) and in hypertensive (n = 27; 4.2 +/- 0.9 micromol/L) patients. In contrast to ADMA, mean total plasma homocysteine concentration were similar in control subjects (10.6 +/- 2.9 micromol/L) and in patients with normal GFR (11.0 +/- 2.9 micromol/L), but were significantly higher in patients with moderate renal failure (17.7 +/- 4.1 micromol/L) and particularly in patients with advanced renal failure (28.2 +/- 10.6 micromol/L). Finally, mean total serum cholesterol concentrations were comparable in the control group and in the three groups of patients with renal disease. In contrast to several traditional cardiovascular risk factors, markedly increased blood concentrations of ADMA, a putative biochemical marker of atherosclerosis, are present even in nonsmoking patients without diabetes with incipient primary renal disease. Thus, the early increase of ADMA levels may be of relevance for the excess cardiovascular morbidity and mortality due to arterio- and atherosclerotic complications in patients with renal disease.     

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.     

Evaluation of stromal metalloproteinases and vascular endothelial growth factors in a spontaneous metastasis model

This study aims to investigate MMP2 and MT1-MMP protein as well as VEGF-C and VEGF-D mRNA expression in tumor cells and distant organs considered to be targets for metastasis in a tumor spontaneous metastasis model previously described. Cultured tumor cells, able to express pro-MMP2, MMP2, pro-MMP9, and MT1-MMP, develop tumor growth and metastasis, mainly in the liver and spleen, when they are injected in the mammary pad gland of Wistar rats. Immunohistochemical studies of tumor masses showed small groups of tumor cells staining for MT1-MMP but not for MMP2. In the liver, tumor metastatic foci and a stromal positive staining for both MMP2 and MT1-MMP were shown. The spleen and lymph nodes, with only scattered metastatic cells, did not show MMPs immunostaining. Using RT-PCR, a significantly higher VEGF-C and VEGF-D gene expression was shown in the liver of tumor-bearing rats respect to normal rats, whereas spleen and lymph nodes did not show significant differences in mRNA VEGF-C/D levels. Taken together, our results suggest that the stroma microenvironment of target organs for metastasis has the ability to produce MMPs and VEGFs that facilitate the anchorage of tumor cells and promote tumor cell growth and angiogenesis.     

Different effects of the liver mitogens triiodo-thyronine and ciprofibrate on the development of rat hepatocellular carcinoma

Previous work has shown that treatment with thyroid hormone (T3) decreased the incidence of rat hepatocellular carcinoma (HCC). The present study was designed to determine whether the inhibitory effect of T3 on HCC development was limited to early steps of the carcinogenetic process or, whether a similar effect could also be exerted by starting T3 treatment at later stages. Hepatic nodules were induced in Fischer rats by a single dose of DENA, followed by a 2-week exposure of the animals to 2-AAF and partial hepatectomy. Rats were then divided into 3 groups: group 1 was maintained on basal diet: group 2 was fed a diet containing 4 mg/kg T3 for a week, every month/7 months, starting 9 weeks after DENA administration: group 3 was exposed to cycles of T3 starting 8 months after initiation. Results demonstrate that inhibition of HCC development was essentially similar in rats exposed to T3 starting either 9 weeks or 8 months after initiation (50% inhibition compared to control rats). We have previously shown that T3-induced nodule regression and HCC inhibition occurred in spite of its mitogenic effect. Therefore, we next wished to determine whether a similar antitumoral effect could be exerted by other liver mitogens, such as peroxisome proliferators. Rats exposed to the initiation-promotion protocol described previously, were subjected to 11 cycles of a T3 or a ciprofibrate-supplemented diet, each cycle consisting of 7 days/month: the incidence of HCC and lung metastases was determined 13.5 months after initiation. Results showed that although treatment with T3 strongly inhibited HCC development (only 31% of T3+ rats showed HCC vs 91% of controls), rats given ciprofibrate developed the same number of HCC as T3-untreated rats. In conclusion, the results of this study showed that the anticarcinogenic effect of T3 is maintained also when treatment begins late in the process, and its antitumoral property appears to be specific and may not be shared by other liver mitogens.