Anti-HLA class I antibody-mediated activation of the PI3K/Akt signaling pathway and induction of Bcl-2 and Bcl-xL expression in endothelial cells

Anti-human leukocyte antigen (HLA) antibodies (Ab) have long been implicated in the process of acute and chronic allograft rejection, yet their mechanism(s) of action is not well understood. The aim of this study was to determine whether ligation of HLA class I molecules by anti-HLA Ab on the surface of human endothelial cells (EC) activates the PI3 Kinase (PI3K)/Akt signaling pathway and downstream target proteins of the cell death apparatus. We report that Ab ligation of major histocompatibility complex (MHC) class I molecules on the surface of EC triggers phosphorylation of Akt, PI3K, and recruitment of PI3K and Akt into a signaling unit with focal adhesion kinase. Signaling through class I also stimulated phosphorylation of Bad and upregulated expression of Bcl-2 and Bcl-xL. Pretreatment of EC with the PI3K inhibitor wortmannin blocked class I-mediated expression of Bcl-2, but not Bcl-xL, suggesting a role for the PI3K/Akt signaling pathway in regulation of class I-induced Bcl-2 expression. The intracellular events initiated by class I ligation were influenced by the concentration of the anti-HLA Ab with the lowest tested concentrations of Ab stimulating the highest level of Akt phosphorylation, Bcl-xL and Bcl-2 expression. Consistent with the in vitro experiments, analysis of biopsy samples from heart transplant recipients with evidence of Ab-mediated rejection exhibited increased Bcl-2 expression on the vascular endothelium. These results suggest that exposure of the graft endothelium to low concentrations of anti-HLA Ab may promote cell survival by transducing signals resulting in upregulation of cell survival genes.     

Renal tubular basement membrane changes in tubulointerstitial damage in patients with glomerular diseases

Injury to renal tubules and interstitium occur in various glomerular diseases, leading to functional impairment. Tubular basement membrane (TBM) is an important component in maintaining tubular epithelial cell integrity. Because ultrastructural changes in these structures had not been studied in detail, the authors analyzed 30 patients with various types of glomerular diseases, including minimal change disease (MCD), focal segmental glomerular sclerosis, IgA nephropathy, diffuse proliferative glomerulonephritis, membranous nephropathy, and lupus nephritis, by light, electron, and immunofluorescence microscopy. Ultrastructural changes in the TBM were studied and morphometric measurements were performed. The tubular basement membranes showed membranous structures, lucent or lytic areas, and tubular epithelial detachment. There was significant linear correlation between these tubular basement membrane changes and terminal complement complex neoantigens. The interstitial widening was due to banded collagen fibers, with anchoring fibers in the TBM. The various glomerular diseases lead to tubulointerstitial damage via changes in the TBM, leading to renal dysfunction.     

Phenolic content, antioxidant effect and cytotoxic activity of Leea indica leaves

ABSTRACT: BACKGROUND: The leaves of Leea indica (Vitaceae), commonly known as 'Huo Tong Shu' in Malaysia, have been traditionally used as natural remedy in folk medicine by the locals. The current study reports the outcome of antioxidant and cytotoxic investigation of L. indica leaves. To the best of our knowledge, this is the first report of L. indica leaf crude ethanol and its fractionated extracts (hexane, ethyl acetate and water) for evaluation of total phenolic content, antioxidant effect and cytotoxic activity against colon cancer cell lines. METHODS: In the present study, L. indica leaf crude ethanol and its fractionated extracts (hexane, ethyl acetate and water) were firstly prepared prior to phenolic content, antioxidant effect and cytotoxic activity assessment. Folin-Ciocalteau's method was used for the measurement of total phenolic content of the extracts. The antioxidant activity was measured by employing three different established testing systems, such as scavenging activity on DPPH (1,1-diphenyl-2-picrylhydrazyl) radicals, reducing power assay and SOD (superoxide dismutase) activity assay. The cytotoxic activity of the extracts were evaluated against three colon cancer cell lines with varying molecular characteristics (HT-29, HCT-15 and HCT-116) by MTT [3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide] assay. RESULTS: The total phenolic content and antioxidant capabilities differed significantly among the L. indica leaf extracts. A strong correlation between total phenolic content and antioxidant properties was found, indicating that phenolic compounds are the major contributor to the antioxidant properties of these extracts. Among the crude ethanol and its fractionated extracts, fractionated water extract showed significantly the highest total phenolic content and strongest antioxidant effect in all the antioxidant testing systems employed in this study. All the four extracts exert no damage to the selected colon cancer cells. CONCLUSIONS: The data obtained in these testing systems clearly establish the antioxidant potency of the fractionated water extract of L. indica leaves. Additional studies should be carried out to isolate and identify the bioactive compounds in the fractionated water extract, in order to provide more convincing evidence.     

Reye-Like Syndrome Due to Margosa Oil Poisoning: Report of a Case with Postmortem Findings

A syndrome similar to Reye's syndrome has been reported in infants and mice after ingestion of margosa oil. Although aflatoxin contamination of the oil has been recognized, autopsy findings in an infant with margosa oil poisoning reveal changes consistent with Reye's syndrome but unlike those described in acute aflatoxicosis. The toxic action of margosa oil may be due to the synergistic effects of aflatoxins and other toxic component(s) present in the oil.     

Renal Tubular Basement Membrane Changes in Tubulointerstitial Damage in Patients with Glomerular Diseases

Injury to renal tubules and interstitium occur in various glomerular diseases, leading to functional impairment. Tubular basement membrane (TBM) is an important component in maintaining tubular epithelial cell integrity. Because ultrastructural changes in these structures had not been studied in detail, the authors analyzed 30 patients with various types of glomerular diseases, including minimal change disease (MCD), focal segmental glomerular sclerosis, IgA nephropathy, diffuse proliferative glomerulonephritis, membranous nephropathy, and lupus nephritis, by light, electron, and immunofluorescence microscopy. Ultrastructural changes in the TBM were studied and morphometric measurements were performed. The tubular basement membranes showed membranous structures, lucent or lytic areas, and tubular epithelial detachment. There was significant linear correlation between these tubular basement membrane changes and terminal complement complex neoantigens. The interstitial widening was due to banded collagen fibers, with anchoring fibers in the TBM. The various glomerular diseases lead to tubulointerstitial damage via changes in the TBM, leading to renal dysfunction.     

Lupus cor pulmonale with electron microscope and immunofluroescent antibody studies.

A case of systemic lupus erythemaosus with an unusual complication of pulmonary hypertension leading to cor pulmonale is reported. Lung biopsy showed an interstitial pneumonitis with pulmonary vascular narrowing causing pulmonary hypertension. These changes appeared to be immunologically mediated by the utilization of IgG and C3. Microtubular virus-like particles were present in the endothelial cell cytoplasm of both lung and kidney.     

Rhabdoid Tumor of the Kidney Is a Component of the Rhabdoid Predisposition Syndrome

The rhabdoid predisposition syndrome (RPS) is characterized by pedigrees in which two or more individuals carry germline mutations of the hSNF5/INI1 tumor suppressor gene. The tumors associated with the syndrome include atypical teratoid/rhabdoid tumor (AT/RT), choroid plexus carcinoma, medulloblastoma, and extrarenal rhabdoid tumor. Rhabdoid tumor of the kidney (RTK) has not been described as part of the RPS. We report a case of a 7-month-old boy with RTK whose sister had a malignant cerebellar tumor followed by a malignant lung and pleural tumor of childhood with typical rhabdoid histology. Molecular genetic analysis of the RTK and tissue from the pleural tumor revealed in both cases identical nonsense mutations of the hSNF5/INI1 gene on chromosome 22q11.2, where thymidine was substituted for cytosine in base 472. The proband had an identical germline mutation. This is the fifth genetically analyzed RPS pedigree and the first to include an RTK.