Israel Medical Association Journal

Background: Rectal administration of iodoacetamide induces colitis by blocking sulphhydryl groups and generating inflammatory mediators. Thalidomide, a non-barbiturate hyp­notic, also has an anti-inflammatory effect, presumably by suppressing the production of tumor necrosis factor alpha. In patients with Crohn’s disease, neutralization or suppression of TNFá reduces inflammation.

Objectives: To evaluate the effects of thalidomide in a model of experimental colitis.

Methods: Colitis was induced in rats by intracolonic administration of 3% iodoacetamide. In the treatment group, thalidomide 50 mg/kg was given daily by gavage and continued for 7 days until the rats were sacrificed. Their colons were then processed for wet weight, lesion area, weight of mucosal scraping, myeloperoxidase activity and histology. Serum levels of TNF were determined.

Results: Colonic wet weight, lesion area, myeloperoxidase activity and serum levels of TNFá were significantly lower (P<0.05) in the treatment group (iodoacetamide + thalido­mide) than the control group (iodoacetamide only). Histologi­cally, colonic inflammation in the treated group was markedly decreased.

Conclusions: Thalidomide effectively decreases colitis induced by iodoacetamide. The mechanism is probably associated with inhibition of TNFá, and should be further studied.
 

There is accumulating evidence that tumor necrosis factor plays a major role in the pathogenesis of rheumatoid arthritis. Recent biotechnological advances have allowed for the development of agents that directly target TNF, a pro-inflammatory cytokine. In the last 2 years, the U.S. Food and Drug Administration and the European Union’s Commission of the European Communities have approved two biological agents for the treatment of refractory RA, etanercept and infliximab. Etanercept is a fusion protein, composed of the Fc portion of immunoglobulin G1 and the extracellular domain of a TNF receptor (p75). Infliximab is a chimeric monoclonal antibody composed of murine variable and human constant regions. In placebo-controlled trials, both agents have proven to be effective and well tolerated in PA patients.

Sex steroid hormones (estrogens, progestagens and androgens) have been associated with healthy and neoplastic pancreatic biology, although the precise significance of the findings has not been well established. Receptors for the three different types of SSH are expressed in normal and tumoral pancreatic tissue with varying profiles related to cell origin (exocrine or endocrine), to type of neoplasm. and probably even to tumoral behavior. The activity of specific enzymes involved in the synthesis and transformation of SSH are increased in some neoplastic pancreatic tissues, which may influence the circulating concentrations of these hormones, such as the low serum testosterone: dihydrotestosterone ratio described in male patients with pancreatic carcinoma. Different patterns of age and gender-related incidence and growth of neoplasms have been identified. Experimental studies have shown that pancreatic carcinogenesis is promoted or inhibited by SSH. At present, the data supporting hormonal manipula­tion for the treatment of these tumors are non-conclusive. Normal and tumoral pancreatic tissues may be regarded as a target for SSH and an additional site of biosynthesis. The influence of these hormones on physiological activities is not well known but should be further explored. The study of SSH in pancreatic neoplasms will provide clues about its origin, development, tumoral behavior, prognosis and more specific hormonal therapy. We review here the evidence favoring the role of SSH and their possible clinical implications in pancreatic function.

Background: Tumor necrosis factor is associated with various local and systemic inflammatory sequelae following snakebite. Xanthine oxidase is a principal mediator of remote tissue injury (e.g., lungs, heart, liver).

Objective: To investigate in a snakebite-like animal model the as yet unexplored role of TNF and XO in mediating organ damage following snakebite.

Methods: Sprague-Dawley rats were injected intramuscularly with a non-lethal 500 g/kg dose of Vipera aspis venom (n=10) or saline (n=10). Blood pressure and heart rate were continuously monitored, TNF- was measured in the blood, and total XO + xanthine dehydrogenase activity was assessed in various tissues. Lung histology and permeability indices were analyzed.

Results: Venom injection caused a significant (P0.05) reduction in both heart rate and invasive arterial pressure. The blood circulating TNF levels were significantly higher in the intoxicated group (P0.05 vs. saline group), with changes seen at 30 minutes from intoxication in both groups. Total XO + XDH activity in the kidney, lung and liver of the venom-injected group was significantly (P0.05) higher than in the saline group, while the activity in the heart was similar.

Conclusions: The mediation of remote organ and hemodynamic changes following intramuscular injection of a non-lethal dose of Vipera aspis venom can be attributed partly to TNF and partly to XO. More research is needed to better understand the role of either compound and the time frame of their activity before specific antagonists can be introduced for snakebite management.
 

Background: Differentiating between benign and malignant submucosal tumors is difficult. Moreover, the natural course of benign-appearing SMTs is not clearly elucidated.

Objectives: To evaluate the natural course of upper gastrointestinal SMTs by endoscopic endosonography.

Methods: We followed 25 consecutive patients with small (<40 mm) SMTs for a mean period of 19 months. Evaluation included maximal tumor diameter, internal echo pattern, and outer margin of lesions.

Results: Follow-up revealed no change in echo features in 24 of 25 patients (96%). In only one patient a homogenous hypoechoic smooth margin lesion converted to a non-homogenous tumor with an irregular outer margin. This lesion also increased in size from 30 to 38 mm. On surgical removal this tumor was found to be a stromal tumor with high malignant potential.

Conclusions: Most small SMTs do not change during a period of 19 months and a conservative policy of surveillance is warranted.

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SMTs= submucosal tumors

Background: Exposure of newborn animals to high concentrations of oxygen leads to diffuse alveolar damage similar to that seen in bronchopulmonary dysplasia in human infants. Therefore, neonatal rats are a suitable practical model of hyperoxic lung damage in human infants.

Objective: To determine the involvement of tumor necrosis factor-alpha and interleukin-6 in lung injury in neonatal rats exposed to 100% O2 concentration.

Methods: A randomized controlled study was designed in which litters of term Sprague-Dawley rat pups were assigned to experimental or control groups. The pups in the experimental group were placed in 100% O2 from birth for 9 days, while the control pups were placed in room air. Twelve to 15 pups from each group were sacrificed on day 1, 3, 6, 9 and 13 after birth for bronchoalveolar lavage collection and lung histologic study. The bronchoalveolar lavage fluid was assayed for TNFα and IL-6.

Results: Newborn rats exposed to 100% O2 for the first 9 days of life showed severe pulmonary edema and hypercellularity on days 1 and 3, which then improved to nearly complete resolution on days 6 and 9. Pulmonary TNFα was produced early on O2 exposure (day 3) and pulmonary IL-6 later (days 6 and 9).

Conclusions: Hyperoxia induces sequential production of pulmonary TNFα and IL-6, which corresponds to the severity of the pathological findings and the known inflammatory and anti-inflammatory role of these cytokines.

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TNFα= tumor necrosis factor-alpha

IL-6= interleukin-6

Background: Cell-mediated immunity is impaired in uremia. Cell-matrix interactions of immune cells such as CD4+T lymphocytes with extracellular matrix are an important requirement for an intact immune response. The adherence of CD4+T cells of healthy subjects (normal T cells) to ECM components is inhibited in the presence of uremic serum. Such decreased adhesive capacity is also found in T cells of dialysis patients. Various chemokines and cytokines affect the attachment of CD4+T cells to ECM.

Objective: To evaluate chemokine (MIP-1β and RANTES) and tumor necrosis factor α-induced adhesion of CD4+T cells to ECM in a uremic milieu.

Methods: We examined adhesion of normal CD4+T cells (resting and activated) to intact ECM in response to soluble or bound chemokines (MIP-1β and RANTES) and to TNF-α following incubation in uremic versus normal serum. Thereafter, we evaluated the adhesion of resting CD4+T cells from dialysis patients in a similar fashion and compared it to that obtained from a healthy control group.

Results: Addition of uremic serum diminished soluble and anchored chemokine-induced attachment of normal resting and activated CD4+T cells to ECM compared to a normal milieu (a peak response of 10–11% vs. 24–29% for soluble chemokines, P<0.001; 12–13% vs. 37–39% for bound chemokines on resting cells, P<0.01; and 18–20% vs. 45–47% for bound chemokines on activated cells, P<0.02). The same pattern of response was noted following stimulation with immobilized TNF-α (7 vs. 12% for resting cells, P<0.05; 17 vs. 51% for activated cells, P<0.01).  Adherence of dialysis patients’ cells to ECM following stimulation with both bound chemokines was reduced compared to control T cells (15–17% vs. 25–32%, P<0.0000). In contrast, adherence following stimulation by TNF-α was of equal magnitude.

Conclusions: Abnormal adhesive capacity of T lymphocytes to ECM in uremia may, in part, be related to a diminished response to MIP-1β, RANTES and TNF-α. However, whereas reduced adhesion to chemokines was present in both normal CD4+T cells in a uremic environment and in dialysis patients’ T cells, TNF-α-induced adhesion was found to be inhibited only in normal cells in a uremic milieu.

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ECM = extracellular matrix

TNF-α = tumor necrosis factor-a

Background: Previous studies have suggested that prolactin may serve as an indicator of disease progression in breast cancer.

Objectives: To evaluate the use of PRL as a serum tumor marker in patients with breast cancer.

Methods: PRL serum level was determined in 99 breast cancer patients and compared with CA 15-3 serum level.

Results: Elevated serum level of PRL (>20 ng/ml) was found in 8 of 99 patients (8.1%). A stratified analysis of prolactin levels according to therapy revealed that PRL levels was increased in 8 of 55 untreated patients (14.5%), but not in patients who received hormonal or chemotherapy in the 3 months preceding the test (0/42 patients, P=0.009). However, mean PRL level was similar in patients with no evidence of disease activity and in patients with active disease (10.2 vs. 8.2 ng/ml, NS). In comparison, CA 15-3 mean level was significantly lower in patients with no evidence of disease as compared to patients with active disease (18.2 vs. 144.7 units/ml, P<0.001). PRL level was increased in 6 of 60 patients (10%) with no evidence of disease and in 2 of 39 (5.2%) with active disease (NS). In comparison, CA 15-3 level was increased in 3 of 60 patients (5%) with no evidence of disease and in 24 of 39 (61.5%) with active disease (P<0.001).

Conclusions: PRL levels are decreased following hormonal or chemotherapy in patients with breast cancer and there is no correlation between PRL serum level and the state of disease. Further studies are needed to clarify a possible clinical significance of hyperprolactinemia in a subset of patients with breast cancer.

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PRL = prolactin