Antimicrobial peptides of the brevinin-2 family isolated from gastric tissue of the frog, Rana esculenta

Four structurally related peptides with potent growth-inhibitory activity towards Escherichia coli were isolated from an extract of the stomach of the European green frog Rana esculenta, and were identified as members of the brevinin-2 family. Two peptides, termed brevinin-2Eg (GIMDTLKNLA10 KTAGKGALQS20 LLNHASCK LS30GQC) and brevinin-2Eh (GIMDTLKNLA10 KTAGKGALQS20 LLNHASCKL S30 KQC) have not been described previously. One peptide is identical to brevinin-2Ec, previously isolated from R. esculenta skin secretions, and one peptide is identical to brevinin-2Ef whose structure has been deduced from a cloned cDNA prepared from a R. esculenta skin cDNA library. The data demonstrate that certain peptides of the brevinin-2 family, like the magainins in the toad, Xenopus laevis, may play an important role in protecting the gastrointestinal tract of Ranid frogs against microbial invasion.     

T cell receptor V beta repertoire in HIV-infection individuals: lack of evidence for selective V beta deletion

The gradual decline of CD4+ T lymphocytes in HIV-infected individuals culminates in the lethal immunosuppression of AIDS. The mechanism of CD4+ T cell loss is currently unknown, but has recently been suggested to occur as a result of an HIV-encoded superantigen which facilitates a selective deletion of T cells expressing specific V beta genes. To verify and extend such observations, peripheral blood leucocytes (PBL) from 15 HIV+ individuals, 10 of which had very low CD4 T cell counts (< 200/mm3), were analysed for T cell receptor (TCR) V beta gene expression. In contrast to a recent study, the results presented here fail to provide evidence that selective loss of V beta-bearing T cells occurs in HIV+ individuals. Furthermore, when PBL from HIV+ individuals were stimulated with Staphylococcal enterotoxin B (SEB), T cells expressing V beta subfamilies known to engage this superantigen were expanded, indicating that such cells were not deleted and were responsive to stimulation by a bacterial superantigen. Collectively, these data suggest that CD4 loss in HIV patients does not occur in a V beta-selective, superantigen-mediated fashion.     

Simplifying scleral fixation of posterior chamber intraocular lenses

We describe a surgical modification for primary scleral fixation of posterior chamber intraocular lenses. The technique keeps intraocular surgical manipulation at a minimum and allows fixation of the lens during accidental rupture of the posterior lens capsule.     

Liposomal daunorubicin in advanced Kaposi's sarcoma: a phase II study

We report a non-randomized Phase II clinical trial to assess the efficacy and safety of liposomal daunorubicin (DaunoXome) in the treatment of AIDS related Kaposi's sarcoma. Eleven homosexual men with advanced Kaposi's sarcoma were entered in the trial. Changes in size, colour and associated oedema of selected 'target' lesions were measured. Clinical, biochemical and haematological toxicities were assessed. Ten subjects were evaluated. A partial response was achieved in four, of whom two subsequently relapsed. Stabilization of Kaposi's sarcoma occurred in the remaining six, maintained until the end of the trial period in four. The drug was generally well tolerated, with few mild symptoms of toxicity. The main problem encountered was haematological toxicity, with three subjects experiencing severe neutropenia (neutrophil count < 0.5 x 10(9)/l). There was no evidence of cardiotoxicity. In this small patient sample, liposomal daunorubicin was an effective and well tolerated agent in the treatment of Kaposi's sarcoma.     

The asystolic donor syndrome: transaminitis and thrombocytopenia after non-heartbeating renal transplantation

BACKGROUND: The use of kidneys from non-heartbeating donors (NHB) remains controversial. An increased incidence of delayed primary function and primary nonfunction is common. We report a characteristic syndrome of transaminitis and thrombocytopenia after NHB renal transplantation, which may be predictive of graft outcome. METHODS: Two case histories are presented, followed by a retrospective analysis of 38 NHB renal grafts performed at Guy's Hospital from 1988 to 1994. Changes in alanine aminotransferase (ALT) and platelet count were compared between recipients of kidneys from NHB and heartbeating donors (HB). To control for possible effects of antilymphocyte globulin (ALG), two matched control groups receiving HB kidneys with (n=32) and without (n=32) ALG were also compared. RESULTS: ALT was elevated in 32 of 38 (84%) of NHB recipients and 19 of 64 (30%) controls (P<0.001). Mean peak ALT was 172+/-20 U/L in NHB and 42+/-6 U/L in HB kidneys (P<0.001). Use of ALG did not influence mean peak ALT. Elevated ALT predicted impaired graft function (P<0.02) and was associated with an increased length of delayed primary function (P<0.001) and risk of transplant nephrectomy (P<0.05). Thrombocytopenia (<100 x 10(9) cells/L) occurred in 18 of 38 (47%) NHB recipients and in 20 of 64 (31%) controls (P<0.05). Mean nadir platelet count (x 10(9) cells/L) was 113+/-10 in NHB, 128+/-9 in HB with ALG, and 164+/-9 in HB without ALG (both P<0.05 vs. NHB). Patients who underwent graft nephrectomy (n=9) had a disproportionate fall in platelet count (mean nadir, 80+/-11 x 10(9) cells/L; P<0.05). CONCLUSIONS: Transaminitis and thrombocytopenia occur commonly after NHB kidney transplantation and are predictive of graft outcome. Recognition of these changes may assist the early management of NHB renal recipients, and also reduce investigation of "anomalous" results in this setting.     

Robust and efficient memory management in Apache AsterixDB

Traditional relational database systems handle data by dividing their memory into sections such as a buffer cache and working memory, assigning a memory budget to each section to efficiently manage a limited amount of overall memory. They also assign memory budgets to memory-intensive operators such as sorts and joins and control the allocation of memory to these operators; each memory-intensive operator attempts to maximize its memory usage to reduce disk I/O cost. Implementing such memory-intensive operators requires a careful design and application of appropriate algorithms that properly utilize memory. Today's Big Data management systems need the ability to handle large amounts of data similarly, as it is unrealistic to assume that truly big data will fit into memory. In this article, we share our memory management experiences in Apache AsterixDB, an open-source Big Data management software platform that scales out horizontally on shared-nothing commodity computing clusters. We describe the implementation of AsterixDB's memory-intensive operators and their designs related to memory management. We also discuss memory management at the global (cluster) level. We conducted an experimental study using several synthetic and real datasets to explore the impact of this work. We believe that future Big Data management system builders can benefit from these experiences.