Reduced Na-K-ATPase in distal nephron in glycerol-induced acute tubular necrosis

To further characterize changes in tubular Na-K-ATPase in acute tubular necrosis (ATN), segmental analysis was performed in rat nephrons. Na-K-ATPase was assayed in the following segments: proximal convolution (PC), proximal straight (PS), outer medullary thick ascending limb (MTAL), cortical thick ascending limb (CTAL), distal convolution (DC) and cortical collecting duct (CCD) in three groups of rats: 1.) intact; 2.) moderate non-oliguric ATN; and 3.) severe oliguric ATN. GFR and CNa/GFR X 100 were in group 1 0.80 +/- 0.05 ml/min and 0.68 +/- 0.06, in group 2 0.14 +/- 0.02 and 1.46 +/- 0.35, and in group 3 0.04 +/- 0.01 and 0.46 +/- 0.15, respectively. Na-K-ATPase in PC and PS were similar in all three groups. Na-K-ATPase levels were in MTAL: in group 1 37 +/- 2 X 10(-11) mol/mm/min, in group 2 20 +/- 1 X 10(-11), P less than 0.001 versus group 1, and in group 3 24 +/- 2 X 10(-11), P less than 0.001 versus group 1. In CTAL Na-K-ATPase levels were: in group 1 40 +/- 2 X 10(-11), in group 2 33 +/- 1 X 10(-11), P less than 0.001 versus group 1, and in group 3 27 +/- 2 X 10(-11), P less than 0.001 versus groups 1 and 2.(ABSTRACT TRUNCATED AT 250 WORDS)     

The Israeli Maternal Perinatal Database: methods and preliminary evaluation

The Israel Maternal Perinatal Database (IMPD) includes the 1980–92 birth cohorts and was created using deterministic linkage, based on a unique identity number. This number is assigned at birth for Israeli-born infants and upon acquiring permanent or temporary residential status for immigrants and is used widely. The IMPD includes ≈1.3 million births and about 400000 mothers with more than one birth, 40 000 mothers with more than three births and 20 000 grand multipara mothers with four births or more. The pretest-based estimates of incorrectly matched births are 2%. The expected percentage of underlinkage is 5–10% for births occurring before 1985. Since 1985, incorrect maternal underlinkages result only when a birth occurs out of Israel to an Israeli resident. One of the advantages of the IMPD is the ability to estimate linkage reliability, validity and censoring effects by comparison with an external data source, the National Population Register, which groups each mother with all her living children under the age of 18 years. One of the potential analysis pitfalls is the effect of censoring at entry as a result of influx of immigrants from the former Soviet Union and Ethiopia.     

Comparison of positive allergy skin tests among asthmatic children from rural and urban areas living within small geographic area.

BACKGROUND: Evidence of increased asthma and allergic response among urban versus rural residents has been reported. OBJECTIVE: To evaluate the prevalence of allergic response among asthmatic children from urban and rural areas living within close proximity. METHODS: In all, 448 asthmatic children from urban (363) and rural (85) areas were studied. The study group consisted of 234 9-year-olds and 214 12-year-olds. A health questionnaire was completed on each child who subsequently underwent allergic skin prick tests (SPTs). RESULTS: There was significantly more positive SPT response to house-dust mite, mold, cat, and cypress among asthmatic children from urban areas compared with children living in rural areas: 58.3% versus 37.6%, 46.1% versus 31.8%, 17.45 versus 5.9%, and 26.2% versus 15.3%, respectively. Positive SPT for indoor allergens were significantly greater among asthmatic urban residents than asthmatic rural residents: 63.3% versus 45.5%, respectively (P < 0.02). Positive SPT response to all the allergens checked was higher among the 12-year-old age group when compared with the 9-year-olds, 34.6% versus 22.7%, respectively (P = 0.05). CONCLUSIONS: Allergic response measured by SPT is significantly more common among asthmatic children from urban areas as opposed to rural, even though both areas are within small distance of one another. Further, asthmatic children living in urban areas demonstrated more allergic response to both indoor and outdoor allergens. The allergic response tends to increase with increased age in both urban and rural asthmatic children.     

Familial Mediterranean fever gene and protection against asthma.

BACKGROUND: Asthma is an inflammatory airway disease caused by interaction between susceptibility genes and diverse environmental factors. In Israel, asthma seems to be familial and more severe in patients of Iraqi Jewish descent. On the other hand, asthma is less frequent in individuals with familial Mediterranean fever, an autoinflammatory disease prevalent in the Iraqi Jewish community and linked to mutations in the familial Mediterranean fever gene, designated MEFV. OBJECTIVES: To explore a possible role for mutated MEFV in the reduced susceptibility to asthma and to determine its expression in Israeli subjects of Iraqi origins. METHODS: Using a case-control approach, we studied the presence of the 3 most common MEFV mutations (M694V, V726A, and E148Q) in DNA samples from 75 patients with asthma and 45 asymptomatic first-degree relatives, all of Iraqi Jewish origin. The severity of asthma was evaluated using a published severity score. RESULTS: Eleven patients with asthma and 14 of their relatives carried 1 or 2 mutations in the MEFV gene, a carrier rate significantly lower in patients with asthma than in their first-degree relatives and in ethnically matched healthy individuals (P < .03 and P < .003, respectively). Carriers of MEFV mutations had less severe disease, compared with noncarriers (P < .002). CONCLUSION: These findings suggest that MEFV mutations may have a protective effect in the pathogenesis of asthma.     

Oral administration of muscle derived small molecules inhibits tumor spread while promoting normal cell growth in mice

Tumor metastases are extremely rare in striated muscles. This is surprising given the fact that this tissue constitutes 60% of body weight. The present study focuses on small molecules produced and secreted by muscle cells which possess anti-cancer activity in vivo. Recently we have shown that a low molecular weight fraction (<1000 Dalton) of skeletal muscle cell conditioned medium (muscle factor-MF), markedly inhibits the proliferation of carcinoma, sarcoma or melanoma cell lines in vitro. The MF exerts a cytostatic effect on tumor cell growth and arrests the cells in the G0/G1 of the cell cycle. However, normal cell proliferation, such as bone marrow and fibroblasts, was stimulated following incubation with MF. In this study, the effect of orally administered MF on melanoma and sarcoma growth was examined in mice. The administration of MF to mice inoculated intravenously with melanoma (B16–F10) or sarcoma (MCA-105) cells, resulted in a statistically significant inhibition of metastatic lung foci. In a different model, melanoma was induced in the foot pad and after development of a local lesion, the leg was amputated. A prolonged survival time was observed in the MF treated groups. Since the MF stimulated bone marrow cell proliferation in vitro, we decided to test its efficacy as an inhibitor of the myelotoxic effect exerted by chemotherapy, in vivo. MF, administered after chemotherapy, restored the number of white blood cells and yielded an increased percentage of neutrophils compared with the decline in these parameters after administration of chemotherapy alone. Thus, it is indicated that MF exerted a systemic anti tumor and chemoprotective effect when given orally. It can be concluded that it is bioavailable and is not biodegradable in the digestive system. MF may be considered as a potential therapy for the prevention of tumor spread. This revised version was published online in July 2006 with corrections to the Cover Date.     

The effect of tyrphostin AG-556 on intimal thickening in a mouse model of arterial injury

BACKGROUND: Inflammation has been shown to play an important role in promoting the response to arterial injury and proinflammatory cytokines, such as tumor necrosis factor (TNF) alpha, are candidate mediators. AG-556 is a tyrosine kinase inhibitor proven to be effective in a model of multiple sclerosis-like syndrome in mice due to its immunomodulating effect. In the current study, we investigated the effect of the tyrphostin AG-556 on neointimal thickening and cytokine profile in a model of arterial injury in the mouse. METHODS: Injury was induced by external cuff placement on the left femoral artery of wild-type C57BL/6 mice. AG-556 dissolved in DMSO was injected intraperitoneally daily to the injured mice in a dosage of 2 mg/mouse. Control mice received DMSO injections. Histological analysis was carried out to assess neointimal formation. Splenocytes were cultured in the absence and presence of a mitogen for evaluation of thymidine incorporation and cytokine production. RESULTS: AG-556 treatment significantly attenuated intimal thickening (43,000+/-17,000 microm2; n=11) when compared to DMSO administration (286,000+/-127,000 microm2; n=10; P<0.05). Basal interferon-gamma production by splenocytes from AG-556-treated mice was increased by approximately 20-fold in comparison with levels in DMSO-treated animals, whereas Con-A induced secretion of the cytokine was similar between both groups. Levels of TNF-alpha, IL-4 and IL-10 in the culture supernatant from treated and non-treated animals did not differ significantly. CONCLUSION: The tyrosine kinase inhibitor AG-556 may have a role in the reduction of intimal thickening. The effect could be mediated via an immune modulating effect involving a significant increase in the smooth muscle cell inhibitory cytokine IFN-gamma.     

Aspirin-Interleukin-3 Interrelationships in Patients With Anti-Phospholipid Syndrome

PROBLEM: Previously we reported on the generation of experimental anti-phospholipid syndrome (APS) in mice. These models were employed to evaluate the efficacy of various novel therapeutic modalities including interleukin-3 (IL-3) and low dose aspirin. The efficacy of the latter was found to be interrelated. Low dose aspirin is capable of inhibiting the activity of the enzyme cyclooxygenase which is responsible for the metabolism of arachidonic acid towards the production of prostaglandins. This shifts the metabolism of arachidonic acid to the other pathway and leads to an overproduction of leukotrienes. The leukotrienes act as stimulators of IL-3 production, a positive cytokine in pregnancy which enhances placental and fetal development. In the current study we evaluated the IL-3 levels in pregnant women with APS and expanded our knowledge on the interrelationships between aspirin, arachidonic acid metabolites and IL-3 in the human system. METHODS: IL-3 levels were recorded in the serum of pregnant women with APS and compared to a control pregnant group. In addition peripheral blood mononuclear cells from healthy subjects were incubated with different concentrations of aspirin or with arachidonic acid metabolites (Leukotriene B4, C4 or PGE₂), and IL-3 production in the culture fluids was evaluated. RESULTS: Serum level of IL-3 in pregnant patients with primary APS, APS secondary to SLE and SLE was lower in comparison to the control group. The in vitro studies revealed that only low dose aspirin (10 mg/μl) stimulated IL-3 production while higher doses of the drug failed to induce the cytokine generation. Leukotriene B4 and C4 were stimulatory whereas PGE₂ acted as inhibitor of IL-3 production. CONCLUSIONS: The serum level of IL-3 is decreased to pregnant women with primary or secondary APS. Low dose aspirin is capable of stimulating EL-3 production in vitro most probably through an elevation of leukotriene production, which may explain its beneficial activity in preventing the manifestations of APS.     

Tumor cell adhesion to frozen lymph node sections — a correlate of lymphatic metastasis in breast carcinoma models of human and rat origin

Summary The role of tumor cell adhesion in lymphatic metastasis of breast cancer was investigatedin vitro using a rat mammary carcinoma model of four cell lines with different metastatic phenotypes, two human breast cancer cell lines, and cryostast sections of normal rat or human lymph nodes, respectively. A positive correlation was found between the adhesion levels obtained with three metastatic rat mammary cell lines (TMT-081 > MT-100M & TMT-50) and a non-metastatic line MT-W9B, the latter being 3–4 fold less adhesive to the lymph node sections than the metastatic tumors. This selective adhesion was specific, as it was not found with cryostat sections of rat liver and brain. Enzyme assays indicated that cell surface glycoproteins bearing terminal -galactoside residues were involved in the adhesion of the rat tumors.Adhesion of the human breast carcinoma cells Hs578T to sections of human lymph nodes was significantly higher than that of the normal breast epithelial cell line Hs578Bst, and comparable to adhesion of a second breast carcinoma line, MCF-7. Moreover, Hs578T cells isolated from regional lymph nodes of tumor-bearing nude mice were significantly more adhesive to human lymph node sections than the parental line.Adhesion of both human and rat tumors could be partially blocked by the addition of the synthetic peptide GRGDSPK and by antibodies directed to the 1 chain of integrin, suggesting that an integrin receptor may played a role in the adhesion. The results suggest that tumor cell adhesion to cryostat sections of lymph nodes is a correlate of the malignant phenotype in mammary tumors of diverse origins, and could be used to delineate the adhesion factors mediating lymphatic metastasis.