EFFECT of pH and ENZYMATIC TREATMENT ON MICROFILTRATION and ULTRAFILTRATION of TANGERINE JUICE

Tangerine (Citrus reticulata blanco) juice clarification by crossflow microfiltration and ultrafiltration using polysulphone flat sheet membranes with nominal molecular weight cut off of 25,000, 50,000, 100,000 and 0.1 μm, 0.2 μm pore sizes was studied. the juice was pretreated by polygalacturonase and pH adjustment. the treated juice was clarified with a laboratory scale filtration unit with effective filtration area of 14 cm². Filtration conditions were transmembrane pressure of 93 to 194 kPa, crossflow velocity of 0.96 to 3.5 m/s and 25°C. Membrane performance was evaluated in terms of volume flux and clarity (% transmittance) of the permeate. Pretreatment of the juice by polygalacturonase and adjustment to pH 2 with HCl resulted in a clearer supernatant than enzyme treatment alone. Maximum flux was obtained with the 0.1 μm microfiltration membrane. Flux increased with transmembrane pressure and crossflow velocity. Flux at 194 kPa and 3.5 m/s was 69 L per square meter per hour. Permeate clarity was better at higher transmembrane pressure and lower velocity, due to the effect of the polarized/fouling layer of solute on the membrane surface, which acted as a secondary “dynamic” filter.     

Antiviral immune responses in Itk-deficient mice

Mice lacking Itk, a T-cell-specific protein tyrosine kinase, have reduced numbers of T cells and reduced responses to allogeneic major histocompatibility molecules. This study analyzed antiviral immune responses in mice deficient for Itk. Primary cytotoxic T-lymphocyte (CTL) responses were analyzed after infection with lymphocytic choriomeningitis virus (LCMV), vaccinia virus (VV), and vesicular stomatitis virus (VSV). Ex vivo CTL activity was consistently reduced by a factor of two to six for the different viruses. CTL responses after restimulation in vitro were similarly reduced unless exogenous cytokines were added. In the presence of interleukin-2 or concanavalin A supernatant, Itk-deficient and control mice responded similarly. Interestingly, while LCMV was completely eliminated by day 8 in both Itk-deficient and control mice, VV cleared from itk-/- mice with delayed kinetics. Antibody responses were evaluated after VSV infection. Both the T-cell-independent neutralizing immunoglobulin M (IgM) and the T-cell-dependent IgG responses were similar in Itk-deficient and control mice. Taken together, the results show that CTL responses are reduced in the absence of Itk whereas antiviral B-cell responses are not affected.     

Ordering the cytochrome c-initiated caspase cascade: hierarchical activation of caspases-2, -3, -6, -7, -8, and -10 in a caspase-9-dependent manner

Exit of cytochrome c from mitochondria into the cytosol has been implicated as an important step in apoptosis. In the cytosol, cytochrome c binds to the CED-4 homologue, Apaf-1, thereby triggering Apaf-1-mediated activation of caspase-9. Caspase-9 is thought to propagate the death signal by triggering other caspase activation events, the details of which remain obscure. Here, we report that six additional caspases (caspases-2, -3, -6, -7, -8, and -10) are processed in cell-free extracts in response to cytochrome c, and that three others (caspases-1, -4, and -5) failed to be activated under the same conditions. In vitro association assays confirmed that caspase-9 selectively bound to Apaf-1, whereas caspases-1, -2, -3, -6, -7, -8, and -10 did not. Depletion of caspase-9 from cell extracts abrogated cytochrome c-inducible activation of caspases-2, -3, -6, -7, -8, and -10, suggesting that caspase-9 is required for all of these downstream caspase activation events. Immunodepletion of caspases-3, -6, and -7 from cell extracts enabled us to order the sequence of caspase activation events downstream of caspase-9 and reveal the presence of a branched caspase cascade. Caspase-3 is required for the activation of four other caspases (-2, -6, -8, and -10) in this pathway and also participates in a feedback amplification loop involving caspase-9.     

Acquired factor VIII inhibitors--successful treatment with an oral outpatient regimen

A rare cause of a spontaneous, life threatening coagulopathy in adults is the development of autoantibodies to factor VIII. We recently had the opportunity to treat seven patients with this disorder. After stabilization, they were given a regimen consisting of prednisone and oral cyclophosphamide. All patients had a complete response to treatment. The median time to response was three weeks. Durable remissions were achieved, making this oral regimen an acceptable treatment for this disorder.     

Withdrawal of survival factors results in activation of the JNK pathway in neuronal cells leading to Fas ligand induction and cell death

The JNK pathway modulates AP-1 activity. While in some cells it may have proliferative and protective roles, in neuronal cells it is involved in apoptosis in response to stress or withdrawal of survival signals. To understand how JNK activation leads to apoptosis, we used PC12 cells and primary neuronal cultures. In PC12 cells, deliberate JNK activation is followed by induction of Fas ligand (FasL) expression and apoptosis. JNK activation detected by c-Jun phosphorylation and FasL induction are also observed after removal of either nerve growth factor from differentiated PC12 cells or KCl from primary cerebellar granule neurons (CGCs). Sequestation of FasL by incubation with a Fas-Fc decoy inhibits apoptosis in all three cases. CGCs derived from gld mice (defective in FasL) are less sensitive to apoptosis caused by KCl removal than wild-type neurons. In PC12 cells, protection is also conferred by a c-Jun mutant lacking JNK phosphoacceptor sites and a small molecule inhibitor of p38 mitogen-activated protein kinase and JNK, which inhibits FasL induction. Hence, the JNK-to-c-Jun-to-FasL pathway is an important mediator of stress-induced neuronal apoptosis.     

Level of anti-mouse-antibody response induced by bi-specific monoclonal antibody OC/TR in ovarian-carcinoma patients is associated with longer survival

OBJECTIVE: The types and amounts of crime experienced by persons with severe mental illness were examined to better understand criminal victimization in this population. METHODS: Subjects were 331 involuntarily admitted psychiatric inpatients who were ordered by the court to outpatient commitment after discharge. Extensive interviews provided information on subjects' experience with crime in the previous four months and their perceived vulnerability to victimization, as well as on their living conditions and substance use. Medical records provided clinical data. RESULTS: The rate of nonviolent criminal victimization (22.4 percent) was similar to that in the general population (21.1 percent). The rate of violent criminal victimization was two and a half times greater than in the general population--8.2 percent versus 3.1 percent. Being an urban resident, using alcohol or drugs, having a secondary diagnosis of a personality disorder, and experiencing transient living conditions before hospitalization were significantly associated with being the victim of a crime. In the multivariate analysis, substance use and transient living conditions were strong predictors of criminal victimization; no demographic or clinical variable was a significant predictor. (Given the relatively high crime rates, subjects' perceived vulnerability to victimization was unexpectedly low; only 16.3 percent expressed concerns about personal safety. Those with a higher level of education expressed greater feelings of vulnerability. CONCLUSIONS: The study found a substantial rate of violent criminal victimization among persons with severe and persistent mental illness. Results suggest that substance use and homelessness make criminal victimization more likely.     

Effect of age on outcome with primary angioplasty versus thrombolysis

OBJECTIVES: The purpose of this study was to determine how risks associated with increasing age differed in patients treated with percutaneous transluminal coronary angioplasty versus thrombolysis. BACKGROUND: Advancing age is a risk factor for adverse outcome in patients with acute myocardial infarction. Primary angioplasty has been thought to be particularly beneficial in higher risk patients including the elderly. There is, however, limited data on any differential incremental benefit of angioplasty compared with thrombolysis in candidates for either treatment. METHODS: In the GUSTO-IIb angioplasty substudy, 1,138 patients were randomized to receive primary angioplasty or accelerated tissue-type plasminogen activator (t-PA). The effect of age on outcome was assessed as a discrete and continuous variable for each treatment group. Models using age as a linear factor as well as cubic spline transformations were used for the major end points of 30-day death or disabling stroke; death or reinfarction; and death, reinfarction or disabling stroke. RESULTS: For each 10-year patient group, outcome was improved with angioplasty (n = 565) compared with t-PA (n = 573). Irrespective of treatment, however, risk increased with age. After adjusting for baseline characteristics, each increment of 10 years of age increased the risk of death or myocardial infarction by 1.32 (95% confidence interval 1.04 to 1.76, p = 0.022). For all adverse outcomes, this incremental effect of increasing age was constant. CONCLUSIONS: Advancing age is associated with worse outcomes, and the risks increase in proportion to age. Although primary angioplasty improves outcomes over thrombolysis, it does not appear to be more beneficial in older than in younger patient groups. The incremental adverse effect of age does not vary by treatment strategy.     

Events in apoptosis. Acidification is downstream of protease activation and BCL-2 protection

Cytoplasmic acidification is now recognized as a feature of apoptosis in a variety of systems. However, its relation to other events in the process of apoptosis is not yet characterized. In this work, we examined the effect of BCL-2 overexpression on acidification mediated by cycloheximide treatment or Fas ligation in Jurkat T-lymphoblasts. We find that BCL-2 overexpression attenuates cytoplasmic acidification and apoptosis detected by annexin V labeling. Acidification and phosphatidylserine externalization were found to occur concurrently. We also examined the requirement for protease activation for cytoplasmic acidification to occur and found that inhibition of interleukin-1beta converting enzyme/CED-3 family proteases (using carbobenzoxy-Val-Ala-Asp-fluoromethylketone, an inhibitor of these proteases) prevents acidification and apoptosis mediated by Fas ligation. These studies suggest that BCL-2 acts at a point upstream of acidification and that protease activation is also upstream of acidification.