Hemodynamic assessment of transluminal angioplasty for lower extremity ischemia

Seventy-two patients underwent hemodynamic testing before and after treatment for occlusive disease of their lower extremities. Percutaneous transluminal angioplasty (PTA) was used to treat lesions in 26 iliac segments and produced 23 initially improved ankle or upper thigh indices, two hemodynamic failures, and one technical failure; PTA for 54 femoropopliteal lesions produced initial hemodynamic improvement in 41 cases, three hemodynamic failures, and ten technical failures. Hemodynamic follow-up of the iliac segments showed improvement in 25 (92%) as measured by the systolic pressure index of the ankle; follow-up of the femoropopliteal segments showed continued patency of 41 (65.9%). The authors analyze these hemodynamic data.     

Small-bowel malabsorption and gastrointestinal malignancy

In addition to lymphoma, there is an increased incidence of gastrointestinal carcinoma in patients with malabsorption due to celiac disease. This is frequently manifested by a loss of response to gluten withdrawal. Four such cases are described: one patient had lymphoma and the other three had cancer of the esophagus, jejunum, and pancreas, respectively. The literature indicates that carcinoma of the esophagus and small bowel is particularly common in patients with celiac disease. These findings suggest that celiac disease should be considered a premalignant condition and that such patients should undergo a regular radiographic survey to detect early cancer.     

Kaposi sarcoma-associated herpesvirus-encoded viral FLICE inhibitory protein (vFLIP) K13 cooperates with Myc to promote lymphoma in mice

Primary effusion lymphoma (PEL) is an aggressive form of lymphoma that is associated with infection by Kaposi sarcoma-associated herpesvirus (KSHV). One of the KSHV genes expressed in PEL cells is K13, a potent activator of the NFκB pathway. K13 transgenic mice develop lymphomas, but after a long period of latency. A possible candidate that could cooperate with K13 in the development of PEL is c-Myc, whose expression is frequently dysregulated in PEL cells. To study the cooperative interaction between K13 and c-Myc in the pathogenesis of PEL, we crossed the K13 transgenic mice to iMyc^Eµ transgenic mice that overexpress Myc. We report that lymphomas in the K13/iMyc^Eµ double transgenic mice developed with shorter latency and were histologically distinct from those observed in the iMyc^Eµ mice. Lymphomas in the K13/iMycEµ mice also lacked the expression of B- and T-cell markers, thus resembling the immunophenotype of PEL. The accelerated development of lymphoma in the K13/iMyc^Eµ mice was associated with increased expression of K13, elevated NFκB activity and decrease in apoptosis. Taken collectively, our results demonstrate a cooperative interaction between the NFκB and Myc pathways in lymphomagenesis.Key words: vFLIP, K13, NFκB, PEL, Myc, KSHV, lymphoma     

Calpain activation impairs neuromuscular transmission in a mouse model of the slow-channel myasthenic syndrome

The slow-channel myasthenic syndrome (SCS) is a hereditary disorder of the acetylcholine receptor (AChR) of the neuromuscular junction (NMJ) that leads to prolonged AChR channel opening, Ca(2+) overload, and degeneration of the NMJ. We used an SCS transgenic mouse model to investigate the role of the calcium-activated protease calpain in the pathogenesis of synaptic dysfunction in SCS. Cleavage of a fluorogenic calpain substrate was increased at the NMJ of dissociated muscle fibers. Inhibition of calpain using a calpastatin (CS) transgene improved strength and neuromuscular transmission. CS caused a 2-fold increase in the frequency of miniature endplate currents (MEPCs) and an increase in NMJ size, but MEPC amplitudes remained reduced. Persistent degeneration of the NMJ was associated with localized activation of the non-calpain protease caspase-3. This study suggests that calpain may act presynaptically to impair NMJ function in SCS but further reveals a role for other cysteine proteases whose inhibition may be of additional therapeutic benefit in SCS and other excitotoxic disorders.     

Kernicterus in an adult who is heterozygous for Crigler-Najjar syndrome and homozygous for Gilbert-type genetic defect

Gilbert syndrome is a common genetic disorder associated with mild unconjugated hyperbilirubinemia and no clinical illness. In contrast, Crigler-Najjar syndrome types I and II are rare genetic disorders associated with severe unconjugated hyperbilirubinemia and a life-long risk of kernicterus. Patients with Gilbert syndrome have low levels of a normal form of uridinediphosphoglucuronate glucuronosyltransferase because of a defect in the promoter region of both alleles, whereas patients with Crigler-Najjar syndrome are homozygous for a defect that yields an abnormal form of the enzyme that has limited or no activity. This case report describes a young adult with Crigler-Najjar syndrome type II in whom kernicterus developed after a laparoscopic cholecystectomy. The development of kernicterus was the result of a largely preventable series of events that lead to an increase in the free fraction of his serum bilirubin. Analysis of his genetic defect showed that he was homozygous for the mutation associated with Gilbert syndrome and heterozygous for a second mutation in the open reading frame of one allele of the bilirubin uridinediphosphoglucuronate glucuronosyltransferase gene. The combined defect leads to severe hyperbilirubinemia and shows how seemingly benign genetic defects, when combined, can cause serious clinical disease. (Gastroenterology 1997 Jun;112(6):2099-103)     

Serum interleukin-3 levels following autologous or allogeneic bone marrow transplantation: effects of T-cell depletion, blood stem cell infusion, and hematopoietic growth factor treatment

Engraftment of marrow following autologous or allogeneic bone marrow transplantation (BMT) may be influenced by quantity and function of stem cells. T lymphocytes, supporting microenvironmental cells, and hematopoietic growth factors (HGF). To elucidate the physiologic role of interleukin-3 (IL-3) in the engraftment process, serum IL-3 levels were measured in over 400 samples from 77 transplant recipients before and for up to 3 weeks following transplantation using a novel enzyme- linked immunoabsorbent assay (ELISA) with a sensitivity of > or = 78 pg/mL. Thirty-seven patients received two to three log T-cell-depleted allografts. In the remaining 40 patients (18 autologous marrow, 12 allogeneic marrow, and 10 autologous peripheral blood [PB] stem cell), T cells were not depleted (non-TCD) from the grafts. A burst of IL-3 (peak levels, 1,500 to 6,000 pg/mL) was detected in the immediate posttransplant period between day 0 and day 14 in all non-TCD recipients and in 21 of 37 (57%) of TCD recipients. A strong inverse relationship between IL-3 levels and absolute neutrophil count (ANC) was observed in both non-TCD recipients (r = -.796) and in TCD recipients (r = -.897). However, both peak IL-3 levels and mean IL-3 levels from day 0 through 14 were significantly lower in TCD recipients compared with either autologous or unmodified allogeneic marrow recipients (P < .01). The lowest peak or mean day 0 through 14 IL-3 levels were observed in matched related recipients undergoing the most aggressive (2.5 to 3.0 log) T-cell-depleted BMT. Autografted patients receiving blood stem cell transplants alone or posttransplant granulocyte colony-stimulating factor (G-CSF) or granulocyte-macrophage colony stimulating factor (GM-CSF) also had significantly lower peak IL- 3 levels (P < .01). In patients receiving TCD grafts, administration of antithymocyte globulin (ATG) posttransplant significantly increased peak IL-3 levels compared with patients not treated with ATG (P < .04). This study shows that endogenous release of IL-3 is strongly associated with myeloid engraftment and inversely related to ANC. Removal of T lymphocytes from donor marrow or acceleration of engraftment by use of stem cells or growth factors appears to blunt the endogenous release of IL-3 whereas use of ATG posttransplant increases IL-3 release.     

Soluble kit receptor in human serum

c-kit encodes the transmembrane receptor tyrosine kinase (Kit) for the recently described ligand stem cell factor (SCF). We have developed an enzyme-linked immunosorbent assay for measuring soluble human Kit and we have used the assay to show high levels of soluble Kit in human serum. The distribution of soluble Kit levels was investigated among 112 normal human serum donors. The mean serum level (+/- SD) was found to be 324 +/- 105 ng/mL with the values falling between 163 ng/mL and 788 ng/mL. No correlation between soluble Kit levels and the sexes or ages of the donors was found. Partial purification using immunoaffinity chromatography allowed us to characterize the soluble Kit from pooled human serum. Antibodies generated to a 497-amino acid recombinant human soluble Kit corresponding to the N-terminal extracellular domain of the receptor recognized the serum-derived soluble Kit by immunoblotting. We found that the serum-derived soluble Kit is glycosylated, with mostly N- linked but also O-linked carbohydrate, and with terminal sialic acid residues. When compared with the recombinant human soluble Kit, the serum-derived material was similar both in size and glycosylation pattern. CNBr cleavage of the isolated serum-derived material followed by amino terminal sequencing confirmed the presence of five peptides expected for the extracellular portion of the Kit molecule. The immunoaffinity purified serum-derived soluble Kit inhibited binding of [125I]SCF to membrane-bound receptor in an in vitro assay. These results indicate that soluble Kit could modulate the activity and functions of SCF in vivo.     

Model of Epstein-Barr virus infection of human thymocytes: expression of viral genome and impact on cellular receptor expression in the T- lymphoblastic cell line, HPB-ALL

Infection of B lymphocytes and epithelial tissue by Epstein-Barr virus (EBV) is associated with malignancy and autoimmunity. The cellular receptor for EBV has been identified as CD21 (CR2). A molecule, which is biochemically and immunologically similar to B-cell CD21, has been identified on a subpopulation of immature thymocytes, suggesting a role for this molecule in the regulation of T-cell development and further suggesting that immature T cells might be susceptible to EBV infection. A growing body of literature now documents the presence of EBV in tumors of T-cell origin. We have evaluated the susceptibility of the human immature T cell line, HPB-ALL, to infection by EBV. Electron microscopy studies showed a rapid internalization of virus by HPB cells. Southern blotting showed the intracellular presence of linear EBV genomes, and components of the virus replicative cycle were identified. Expression of the BamHI Z region of the genome, encoding the nuclear protein, ZEBRA, which is strictly associated with productive infection in B cells, was detected in HPB-ALL cells. A spliced variant of Z, RAZ, was also identified. Cell surface expression of EBV late antigens was observed to occur transiently. Infection of HPB cells was also accompanied by altered expression of T-cell surface molecules involved in antigen recognition, a process critical to normal development of the T-cell repertoire. Delineation of the outcome of T- cell infection by EBV may lead to a better understanding of the role of this virus in autoimmune processes and malignancy.