Diagnosis and surgical treatment of colonic duplication in a young woman.
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Publications and source records attributed to R Bona.
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The recent literature contains reports of thrombotic episodes occurring in patients with human immunodeficiency virus (HIV) infection and various abnormalities predisposing to a hypercoagulable state have also been reported in such patients. To study the incidence of thrombosis in patients infected with HIV, and to assess the correlation of thrombosis with the degree of immunosuppression as well as the association with active illnesses and neoplasms, we reviewed the charts of 131 patients, which include all the patients with the diagnosis of HIV admitted or seen in the clinic between January 1, 1993, and January 1, 1998. The diagnosis of thrombosis was based on documented reports of venous plethysmography or venography for deep venous thrombosis and ventilation-perfusion scan or pulmonary angiography for pulmonary embolus. Risk factors for thrombotic disease were evaluated including general risk factors such as family history, ambulatory status, medications, and data were also collected regarding CD4 cell counts and the presence of concurrent or remote opportunistic infections, acquired immune deficiency syndrome (AIDS)-related malignancy or other AIDS-related diseases at the time of diagnosis of the thrombotic event. We also reviewed the medical literature via MEDLINE and found 45 cases of patients with HIV who developed thromboembolic complications. We found thrombotic complications in 9 of 37 patients with a CD4 count less than 200 cells/mm3 and in 1 of the remaining 94 patients with a CD4 count more than 200 cells/mm3. The difference was significant, with p = 0.00004, and the estimated odds of an event given CD4 cell counts less than 200/mm3 is 29.89 (95% confidence interval). Three patients had abnormalities of anticoagulation proteins. There was a history of opportunistic infections in 5 patients and malignancy in 3 patients. Two patients with autoimmune hemolytic anemia (AIHA) secondary to HIV-infection developed PE upon transfusion of packed red blood cells. The results of this study suggests that AIDS appears to predispose to thrombosis. It also revealed a significant correlation between thrombotic disease and CD4 counts (<200/mm3) as well as the presence of opportunistic infections, AIDS-related neoplasms, or autoimmune disorders associated with HIV such as AIHA. Therefore, clinicians caring for these patients should be aware of thromboembolic disease as a possible complication of AIDS. Further studies to elucidate the mechanisms underlying this abnormal hemostatic profile, the epidemiology, and to answer several questions such as should patients with risk factors for HIV infection who develop thromboembolic complications be further evaluated including tests for HIV are warranted.
PURPOSE: The recent introduction of the immune suppressor cyclosporin for treatment of steroid-refractory ulcerative colitis has required surgeons to perform a colectomy in those patients who eventually fail this rescue treatment, thus raising questions as to the safety of surgery as performed in patients with a heavily manipulated immune system. To assess the rates of mortality and morbidity in this setting, we studied a cohort of consecutive patients who had surgery after failing cyclosporin for refractory ulcerative colitis at our center. METHODS: Between January 1991 and December 1996, 25 patients with ulcerative colitis underwent restorative proctocolectomy performed in three steps (21 patients) and in two steps (4 patients). Seventeen of the 25 patients (68 percent) were initial nonresponders to a dose of 2 mg/kg/day of intravenous cyclosporin and underwent surgery immediately, the remaining 8 (32 percent) relapsed as outpatients on oral cyclosporin and were readmitted for surgery. RESULTS: There was no operative mortality. Nine patients of the 25 developed postoperative (early) complications (36 percent). The three-step operation subset had a 28 percent complication rate, the two-step 75 percent. Three patients needed reoperation. A total of 11 patients (44 percent) reported with late complications: two patients required surgical treatment, one for obstruction and one for pouch-perianal fistula. Three cases of pouchitis were recorded. No patient required pouch removal. CONCLUSION: Given the absence of postoperative mortality and a low overall complication rate, restorative proctocolectomy can safely be performed in patients who fail rescue treatment with a dose of 2 mg/kg of cyclosporin for steroid-refractory ulcerative colitis. Corollary evidence in this article hints but does not prove that the three-step procedure is safer than the two-step operation.
F12 human immunodeficiency virus type 1 (HIV-1) nef is a naturally occurring nef mutant cloned from the provirus of a nonproductive, nondefective, and interfering HIV-1 variant (F12-HIV). We have already shown that cells stably transfected with a vector expressing the F12-HIV nef allele do not downregulate CD4 receptors and, more peculiarly, become resistant to the replication of wild type (wt) HIV. In order to investigate the mechanism of action of such an HIV inhibition, the F12-HIV nef gene was expressed in the context of the NL4-3 HIV-1 infectious molecular clone by replacing the wt nef gene (NL4-3/chi). Through this experimental approach we established the following. First, NL4-3/chi and nef-defective (Deltanef) NL4-3 viral particles behave very similarly in terms of viral entry and HIV protein production during the first replicative cycle. Second, no viral particles were produced from cells infected with NL4-3/chi virions, whatever the multiplicity of infection used. The viral inhibition apparently occurs at level of viral assembling and/or release. Third, this block could not be relieved by in-trans expression of wt nef. Finally, NL4-3/chi reverts to a producer HIV strain when F12-HIV Nef is deprived of its myristoyl residue. Through a CD4 downregulation competition assay, we demonstrated that F12-HIV Nef protein potently inhibits the CD4 downregulation induced by wt Nef. Moreover, we observed a redistribution of CD4 receptors at the cell margin induced by F12-HIV Nef. These observations strongly suggest that F12-HIV Nef maintains the ability to interact with the intracytoplasmic tail of the CD4 receptor molecule. Remarkably, we distinguished the intracytoplasmic tails of Env gp41 and CD4 as, respectively, viral and cellular targets of the F12-HIV Nef-induced viral retention. For the first time, the inhibition of the viral life cycle by means of in-cis expression of a Nef mutant is here reported. Delineation of the F12-HIV Nef mechanism of action may offer additional approaches to interference with the propagation of HIV infection.
We previously demonstrated that expression of the nonproducer F12-human immunodeficiency virus type 1 (HIV-1) variant induces a block in the replication of superinfecting HIV that does not depend on the down-regulation of CD4 HIV receptors. In order to individuate the gene(s) involved in F12-HIV-induced interference, vectors expressing each of the nine F12-HIV proteins were transfected in HIV-susceptible HeLa CD4 cells. Pools of cell clones stably producing each viral protein were infected with HIV-1, and virus release was measured in terms of reverse transcriptase activity in supernatants. We hereby demonstrate that HeLa CD4 cells expressing the F12-HIV gag, vif, or nef gene were resistant, to different degrees, to infection with T-cell-line-adapted HIV-1 strains. Conversely, expression of either the tat, rev, or vpu F12-HIV gene increased the rate of HIV release, and no apparent effects on HIV replication were observed in cells expressing either the F12-HIV vpr, pol, or env gene. No variation of CD4 exposure was detected in any of the uninfected HeLa CD4 pools. These data indicate that F12-HIV homologous viral interference is the consequence of the synergistic anti-HIV effects of Gag, Vif, and Nef proteins. Retrovirus vectors expressing F12-HIV vif or nef allowed us to further establish that the expression of each mutated protein (i) inhibits the replication of clinical HIV-1 isolates as well, (ii) impairs the infectivity of the virus released by cells chronically infected with HIV-1, and (iii) limitedly to F12-HIV Vif protein, induces HIV resistance in both vif-permissive and vif-nonpermissive cells. The levels of action of F12-HIV vif and nef anti-HIV effects were also determined. We observed that HIV virions emerging from the first viral cycle on F12-HIV vif-expressing cells, although released in unaltered amounts, had a strongly reduced ability to initiate the retrotranscription process when they reinfected parental HeLa CD4 cells. Differently, we observed that expression of F12-HIV Nef protein affects the HIV life cycle at the level of viral assembling and/or release. For the first time, an inhibitory effect on the HIV life cycle in both acutely and chronically infected cells induced by mutated Vif and Nef HIV-1 proteins is described. These genes could thus be proposed as new useful reagents for anti-HIV gene therapy.
Recent findings have shown that the expression of the seven trans-membrane G-protein-coupled CXCR4 (the receptor for the stromal cell-derived factor [SDF]-1 chemokine) is necessary for the entry of T-lymphotropic human immunodeficiency virus (HIV) strains, acting as a coreceptor of the CD4 molecule. In the human system, the role of CXCR4 in HIV infection has been determined through env-mediated cell fusion assays and confirmed by blocking viral entry in CD4+/CXCR4+ cells by SDF-1 pretreatment. We observed that the human megakaryoblastic CD4+ UT-7 cell line fails to express CXCR4 RNA and is fully resistant to HIV entry. Transfection of an expression vector containing the CXCR4 c-DNA rendered UT-7 cells readily infectable by different T-lymphotropic syncytium-inducing HIV-1 and HIV-2 isolates. Interestingly, HIV-1 infection of CXCR4 expressing UT-7 cells (named UT-7/fus) induces the formation of polynucleated cells through a process highly reminiscent of megakaryocytic differentiation and maturation. On the contrary, no morphologic changes were observed in HIV-2-infected UT-7/fus cells. These findings further strengthen the role of CXCR4 as a molecule necessary for the replication of T-lymphotropic HIV-1 and HIV-2 isolates and provide a useful model to study the functional role of CD4 coreceptors in HIV infection.
(S)-Hydroxynitrile lyase (Hnl) from the tropical rubber tree Hevea brasiliensis catalyzes the formation of (S)-cyanohydrins from hydrocyanic acid and aldehydes or ketones. This enzyme accepts aliphatic, aromatic, and heterocyclic carbonyl compounds as substrates and is therefore considered a potent biocatalyst for the industrial production of optically active chemicals. Limitations in enzyme supply from natural resources were overcome by production of the enzyme in the microbial host systems Escherichia coli, Saccharomyces cerevisiae, and Pichia pastoris. Expression of Hnl in the prokaryotic system led to the formation of inclusion bodies whereas in both yeast hosts high levels of soluble protein were obtained. Highest yields were obtained in a high cell density batch fermentation of a P. pastoris transformant that expressed heterologous Hnl to about 50% of the soluble cytosolic protein. At a cell density of 100 g/liter cell dry weight, a volume yield of 22 g/liter of heterologous product was obtained. Attempts to produce the Hnl protein extracellularly with the yeast hosts by applying different leader peptide strategies were not successful. Immunofluorescence microscopy studies indicated that the secretion-directed heterologous Hnl protein accumulated in the plasma membrane forming aggregated clusters of inactive protein.
The expression of the nonproducer F12-HIV-1 genome has been previously shown to protect the host cell from HIV superinfection. In order to estimate the efficacy of the F12-HIV genome as an anti-HIV reagent also in cells already infected, an HIV-1 chronically infected Hut-78 cell clone (D10) was superinfected with an amphotropic mouse/human pseudotype retrovirus whose genome expresses both the F12-HIV genome and the selection marker gene (i.e. the c-DNA of a truncated form of the nerve growth factor receptor, NGFr) under the control of F12-HIV 5'LTR. D10 cells homogenously expressing the F12-HIV genome (T-D10) released unaltered amounts of retrovirions whose infectivity was, however, dramatically impaired (from 9 x 10(3) in D10 to < 10(0.5). TCID50/ml in T-D10 supernatants). Electron microscopy showed that the morphology of retrovirions released by T-D10 cells was heavily altered, both in size and shape. Furthermore, no retrotranscription products were detectable in CD4 cells challenged with T-D10 retrovirions. For the first time, the block in the infectivity of HIV released from already infected cells through the expression of an anti-HIV retroviral vector was demonstrated. These data could have important implications both from a perspective of F12-HIV-based anti-HIV gene therapy and, in general, on the role that nonproducer and/or defective HIV could play 'in vivo' in HIV infection and AIDS pathogenesis.
UNLABELLED: We performed a double-blind, randomized clinical trial to compare the efficacy and safety of three different subcutaneous (s.c.) low molecular weight heparin doses (ardeparin sodium 25, 35, or 50 anti-Xa U/kg twice daily [BID]) to adjusted-dose warfarin (international normalized ratio [INR] = 2.0 to 3.0), as venous thromboembolism prophylaxis after total knee replacement surgery. The primary endpoint was total venous thromboembolism prevalence, defined as deep vein thrombosis discovered at postoperative venography of the operated leg, or symptomatic, objectively-documented pulmonary embolism. Of 860 patients randomized, 680 (79%) had an evaluable venogram or pulmonary embolism. The total venous thromboembolism prevalence was significantly greater among patients prophylaxed with warfarin compared to ardeparin 50 BID (38% vs 27%, p = 0.019); the prevalence among ardeparin 25 BID (37%) and 35 BID (28%) patients was similar to warfarin and ardeparin 50 BID patients, respectively. Overt bleeding occurred in 22 (7.9%) ardeparin 50 BID patients compared to 12 (4.4%) warfarin patients (p = 0.08), and in seven ardeparin 25 and 35 BID patients each (5.2% and 5.0%, respectively). Compared to the warfarin group, blood loss was significantly greater in the ardeparin 50 and 25 BID groups, and not different in the ardeparin 35 BID group. CONCLUSIONS: Postoperative, unmonitored, fixed-dose ardeparin 50 anti-Xa U/kg s.c. BID is significantly more effective than adjusted-dose warfarin for this indication. Although overt bleeding among warfarin and ardeparin 50 BID patients did not differ significantly, ardeparin 50 BID patients had significantly greater blood loss. Ardeparin 35 anti-Xa U/kg s.c.BID may provide efficacy similar to ardeparin 50 anti-Xa U/kg s.c. BID but with reduced bleeding.
A Hut-78 cell clone (F12) harboring a nonproducer human immunodeficiency virus (HIV-1) variant shows complete resistance to HIV-1 or HIV-2 superinfection. The F12-HIV provirus produces an altered HIV-1 protein pattern and cannot generate even immature viral particles. We demonstrated that HeLa CD4+ cells transfected with the F12-HIV genome resist HIV superinfection through a CD4-independent mechanism. As F12-HIV appears to be a useful system to induce anti-HIV intracellular immunization, we constructed various retroviral vectors containing the F12-HIV genome, modified by elimination of the F12 3'LTR and part of its nef gene, inserted 'antisense' with respect to the Moloney murine leukemia virus 5' LTR. Here we show that recombinant retroviral particles carrying the N2/F12-HIV nef- (as) construct can stably transduce both CEMss human cells and primary human peripheral blood lymphocytes, inducing the expression of the F12-HIV genome. These results could open the way to an anti-AIDS gene therapy strategy based on F12-HIV-induced intracellular immunization.
An Hut-78 cell clone (F12) harboring a nonproducer human immunodeficiency virus-1 (HIV) variant, and showing a complete resistance to HIV-1 or HIV-2 superinfection, was previously characterized. We demonstrated that the replication of the superinfecting HIVs is blocked at the retrotranscription step, despite the CD4 down-regulation, since HIVs are able to cross the Hut-78/F12 cell membrane. In order to establish if the expression of the HIV-1 variant (F12/HIV) could be per se sufficient to induce the homologous viral interference shown in the F12 cells, the whole F12/HIV provirus was cloned and transfected in He-La CD4+ cells. In F12/HIV expressing He-La CD4+ clones, both the viral proteins expressed and the HIV nonproducer phenotype remain unmodified compared to F12 cells. Furthermore, despite the full expression of CD4 HIV receptors, the life cycle of the superinfecting HIV could be either strongly inhibited or totally abolished, depending on the cell clone considered. The inhibition of the superinfecting HIV was also reproduced when an HIV infectious molecular clone was transfected in F12/HIV He-La CD4+ clones, thus indicating that a post-cDNA synthesis block may operate against the superinfecting HIV. These data demonstrate that HIV susceptibility could be abrogated in cells expressing the F12/HIV genome, even in absence of any CD4 down-regulation.
In order to determine whether there is a relationship between acquired free protein S deficiency and increased thrombin generation, we performed a cross-sectional study of patients with systemic lupus erythematosus (SLE). Plasma samples were assayed for free protein S and were correlated to levels of prothrombin fragments (F1 + 2); an elevated level of F1 + 2 was used as a surrogate marker for a prothrombotic state. Assays for anticardiolipin antibodies (ACA) and lupus anticoagulant (LA) were performed on two separate blood samples taken at least 3 months apart in order to detect the presence of antiphospholipid antibodies. Of the 36 subjects, 9 had reduced free protein S levels compared to 0 of 21 controls (P = 0.01) and the mean free protein S level was significantly lower in the SLE population than in controls (0.30 +/- 0.08 U/mL versus 0.43 +/- 0.10 U/mL, P < 0.001). Of the 24 subjects with antiphospholipid antibodies, 9 had reduced free protein S levels, compared to 0 of 12 subjects without antiphospholipid antibodies (P = .01). The mean F1 + 2 level was significantly higher in study subjects with reduced free protein S levels than in those with normal free protein S levels (1.22 +/- 0.50 nmol/L versus 0.78 +/- 0.27 nmol/L, P = 0.05). This study confirms an association between antiphospholipid antibodies and reduced free protein S levels and demonstrates that patients with SLE and acquired free protein S deficiency generate more thrombin than patients with SLE and normal free protein S levels. Further studies are needed to determine whether the thrombotic diathesis associated with the presence of antiphospholipid antibodies is directly caused by the concomitant presence of acquired free protein S deficiency.
The availability of monoclonal-antibody-purified factor VIII (FVIII) concentrates allows us to test the hypothesis, based on in vitro observations, that their use in HIV seropositive haemophiliacs would result in a difference in the rate of deterioration of immune function. We designed a multicentre, prospective, randomised, controlled study of symptom-free HIV-infected patients with haemophilia A who were assigned to receive either an intermediate-purity or monoclonal-antibody-purified product. All had CD4 lymphocyte counts of 100-600/microL, were negative for hepatitis B surface antigen, had not received any antiretroviral or immunomodulating drugs before study entry, and had previously received replacement therapy with intermediate purity FVIII concentrates. Use of antiretroviral therapy was permitted. 60 patients were recruited and 30 were assigned to each group. 35 completed the 3 year study, 20 in the monoclonal arm and 15 in the intermediate-purity arm. Among those completing the study, there were no differences between the two groups in the occurrence of AIDS-defining diagnoses (1 in each group). There were, however, striking and significant differences in terms of changes in absolute CD4 counts. The group receiving monoclonal-antibody-purified concentrates had essentially stable counts while a significant drop was observed in the group receiving intermediate-purity FVIII. These differences were independent of the use of antiretroviral therapy. These observations support the use of high-purity concentrates in the treatment of symptom-free HIV-positive patients with haemophilia A, and they should be taken into account along with cost, by doctors making therapeutic decisions.
The objective of this study is to determine whether patients with systemic lupus erythematosus (SLE) and anticardiolipin antibodies (ACA) have biochemical evidence of an ongoing prothrombotic state. Using a cross-sectional analysis of a cohort design in an outpatient SLE clinic setting, 43 consecutive patients with SLE participated. Patients underwent clinical and laboratory evaluations on two separate occasions at least 3 months apart. As part of the clinical evaluation, the following were ascertained: (1) the ongoing use of warfarin therapy; (2) the presence of prior venous and arterial thromboembolic disease by history, critical review of objective tests, and examination for reflux in the deep veins of the legs as an indicator of venous thrombosis; and (3) disease-related activity by performing a lupus activity criteria count (LACC). As part of the laboratory evaluation, blood was taken on both occasions and assayed for prothrombin fragments (F1 + 2) and fibrinopeptide A (FPA), as indices of thrombin generation and activity, respectively, and ACA. For the analyses, patients were classified as ACA+ if the assay was abnormal on both occasions and ACA- if the assay was negative on both occasions or negative on one occasion and positive on the other. ACA+ patients had: (1) a significantly higher mean level of F1 + 2 (1.07 nmol/L) than ACA- patients (0.79 nmol/L; P = .02) and patients receiving warfarin (0.47 nmol/L; P = .009) and (2) a significantly higher mean level of FPA (1.01 nmol/L) than ACA- patients (0.45 nmol/L; P = .02). When patients with prior thromboembolism were excluded from the analysis, significant differences in the mean levels of F1 + 2 and FPA between ACA+ and ACA- patients were still seen, whereas when patients with prior thromboembolism and/or active disease were excluded from the analysis, a significant difference in the mean level of FPA and a nonsignificant trend in the mean level of F1 + 2 were seen. The results of this study support the hypothesis that the presence of ACA in SLE patients is associated with an ongoing prothrombotic state.
In order to determine the relative frequencies of left and right leg venous thrombosis during pregnancy and the frequencies of venous thrombosis during the three trimesters, a cohort study of 60 consecutive patients with a first episode of venous thrombosis during pregnancy was performed. Fifty-eight women had isolated left leg thrombosis, two patients had bilateral venous thrombosis and no patient had isolated right leg venous thrombosis. Thirteen patients had venous thrombosis during the first trimester (21.7%), 28 during the second trimester (46.7%) and 19 during the third trimester (31.7%). These findings indicate that patients with symptoms in the right leg rarely have venous thrombosis. Because leg pain and swelling occur most frequently during the third trimester but venous thrombosis is relatively equally distributed during all three trimesters, patients presenting earlier during pregnancy are more likely to have venous thrombosis than patients presenting later during pregnancy.
Spermine and spermidine, ubiquitous polyamines present in bacteria and animal cells, are also involved in cell growth. Since they interact with the double helix, they can stabilize the DNA molecule. Recent evidence of the antimutagenic and anticarcinogenic capacity of spermine has focused attention on the mechanism(s) by which such agents can protect cells from induced damages. In the present paper we show the ability of spermine and spermidine to decrease the level of sister chromatid exchanges induced in Chinese hamster ovary cells cultivated in vitro, by treating them with Psoralen + UVA irradiation (able to induce mainly monoadducts and DNA cross-links). Two different mechanisms of polyamine action can be invoked to explain the preservative activity of this class of agents.
To compare the sensitivity, specificity, and predictive values of compression ultrasonography (US) in postoperative orthopedic patients with those of (a) impedance plethysmography in postoperative patients and (b) compression US in symptomatic outpatients, the authors performed an investigator-blinded cohort study. One hundred thirty-four consecutive inpatients who had undergone elective knee-replacement surgery or surgery for a fractured hip and 65 consecutive outpatients with clinically suspected venous thrombosis who had undergone venography were evaluated. Compression US allowed detection of 11 of 21 (52.4%) proximal-vein thrombi but was insensitive to calf-vein thrombi in the orthopedic patients. Compression US had a significantly greater specificity and positive predictive value than impedance plethysmography for all thrombi in orthopedic patients; compression US also had greater sensitivity. The sensitivity of compression US for proximal-vein thrombi was significantly higher (92.1%) in symptomatic outpatients than in orthopedic patients. The authors conclude that compression US has significant advantages over impedance plethysmography in the detection of proximal-vein thrombi in patients who have undergone hip- or knee-replacement surgery.