Application of random amplified polymorphic DNA PCR for genomic analysis of HIV-1-infected individuals

Random amplified polymorphic DNA polymerase chain reaction (RAPD-PCR) is a DNA fingerprinting technique used to detect genomic polymorphisms. We employed sixteen different RAPD-PCR 10-mer primers to amplify DNA from the peripheral blood mononuclear cells (PBMC) of 80 HIV-1-infected individuals. These individuals were previously identified as either heterozygotes (+ /delta32) and homozygotes (+/+) for the CCR5 locus by PCR with gene specific primers. Four of the sixteen randomly selected RAPD primers produced distinguishable banding profiles between CCR5 (+/delta32) heterozygotes and CCR5 (+/+ ) homozygotes. Direct sequencing of some RAPD-PCR products obtained with one of the four RAPD primers that were tested yielded clearly readable, but limited sequences, which were similar to portions of the previously published sequences for (+/+ ) homozygotes (98% similarity) and (+/delta32) heterozygotes (87% similarity) of the CCR5 alleles. Thus, the RAPD-PCR technique may be useful for the identification of human molecular markers that may correlate with susceptibility to HIV-1-infection, or differences in disease progression among HIV-l-infected individuals.

Interferon-alpha enhances CD95L-induced apoptosis of human malignant glioma cells

CD95 ligand (CD95L)-induced apoptosis is a novel immunotherapeutic approach to malignant glioma. Here, we report that interferon-alpha (IFN-alpha) sensitizes LN-229 and T98G human malignant glioma cells to CD95L-induced apoptosis. In contrast to the effects of IFN-gamma and TNF-alpha which sensitize glioma cells to CD95 antibody-induced apoptosis in part by enhancing CD95 expression, IFN-alpha has no effect on CD95 expression at the cell surface of LN-229 and T98G cells. To confirm that changes in CD95 expression are not required for the effects of IFN-alpha, we show that IFN-alpha enhances CD95L-induced apoptosis even in CD95-transfected LN-308 glioma cells. These LN-308 cells have little endogenous CD95 expression but express high levels of CD95 from a stably integrated CD95 expression plasmid. The sensitizing effects of IFN-alpha appear to be independent of cell cycle effects of IFN-alpha and are unaffected by ectopic expression of the bcl-2 proto-oncogene. IFN-alpha enhances CD95L-induced activation of caspase-3, a critical mediator of CD95L-induced cell death. IFN-alpha also increases the cytotoxic effects of BCNU, teniposide and cytarabine in both cell lines, and of vincristine in LN-229 cells. Doxorubicin and 5-fluorouracil toxicity are unaffected by IFN-alpha. IFN-alpha may be a useful adjunct to novel strategies of immunochemotherapy for malignant gliomas that target CD95-mediated apoptosis.

Pharmacokinetics of meloxicam in animals and the relevance to humans

The pharmacokinetic profile of the new nonsteroidal anti-inflammatory drug meloxicam was investigated in a number of animal species, including mice, rats, dogs, mini-pigs, and baboons, after administration of [14C]meloxicam. The plasma concentration-time profiles for meloxicam in rats and dogs were comparable to that in humans, whereas there were marked differences between humans and mice, mini-pigs, and baboons. The highest tissue concentrations of meloxicam in rats and mini-pigs were seen in the liver and kidneys. In contrast, low concentrations of meloxicam were found in the central nervous system, compared with those in plasma. The excretion balance in mini-pigs resembled that in humans, with almost equal concentrations being eliminated in the urine and the feces. As in humans, meloxicam circulated mainly in the form of the parent compound in the plasma of mice, rats, dogs, mini-pigs, and baboons. The main metabolites in rats, mini-pigs, and humans were a 5'-hydroxymethyl derivative (AF-UH 1 SE) and a 5'-carboxy metabolite (UH-AC 110 SE). The percentage of meloxicam binding to protein was higher in rats and humans (>99%) than in other species. The pharmacokinetic profile of meloxicam in rats most closely resembles that in humans; therefore, reliable clinical predictions can be made from studies in this rodent species.

Mouse procathepsin E gene: molecular organisation and chromosomal localisation

A 15.6 kb genomic clone encompassing the mouse procathepsin E gene was isolated and mapped. Sequencing revealed that the gene consists of nine exons followed by a polyadenylation signal at the 3'-end. The 5'-flanking region appears to be a TATA-less promoter but contains a nucleotide sequence that matches perfectly with the consensus motif of an initiator element [S.T. Smale, Biochim. Biophys. Acta 1351 (1997) 73-88.] to direct accurate initiation of transcription by RNA polymerase. This overlaps the site that was determined for the start of transcription. The absence of features considered typical of TATA-box regulated or housekeeping types of genes is consistent with the low levels of procathepsin E gene expression that are normally observed and might imply a unique sensitivity to or requirement for tissue-specific transcription factors that would account for the sporadic distribution of this aspartic proteinase in cells and tissues. The single copy of the procathepsin E gene was located on chromosome 1, near to that of mouse prorenin, a closely related aspartic proteinase involved in blood pressure regulation.

Simplicity is best: the learning experience of Good Shepherd Home

Quality improvement efforts need not be expensive and can produce positive results almost immediately if a systemic, comprehensive model is used and if top-level management is truly supportive. The following article presents a case study of a successful quality improvement process mounted at Good Shepherd Home, a rehabilitation hospital in Allentown, PA. It discusses the key items of the systems approach and looks at how the items have been implemented and integrated and the future of the process.

Cathepsin L: critical role in Ii degradation and CD4 T cell selection in the thymus

Degradation of invariant chain (Ii) is a critical step in major histocompatibility complex class II-restricted antigen presentation. Cathepsin L was found to be necessary for Ii degradation in cortical thymic epithelial cells (cTECs), but not in bone marrow (BM)-derived antigen-presenting cells (APCs). Consequently, positive selection of CD4+ T cells was reduced. Because different cysteine proteinases are responsible for specific Ii degradation steps in cTECs and BM-derived APCs, the proteolytic environment in cells mediating positive and negative selection may be distinct. The identification of a protease involved in class II presentation in a tissue-specific manner suggests a potential means of manipulating CD4+ T cell responsiveness in vivo.

Cathepsins B and D are dispensable for major histocompatibility complex class II-mediated antigen presentation

Antigen presentation by major histocompatibility complex (MHC) class II molecules requires the participation of different proteases in the endocytic route to degrade endocytosed antigens as well as the MHC class II-associated invariant chain (Ii). Thus far, only the cysteine protease cathepsin (Cat) S appears essential for complete destruction of Ii. The enzymes involved in degradation of the antigens themselves remain to be identified. Degradation of antigens in vitro and experiments using protease inhibitors have suggested that Cat B and Cat D, two major aspartyl and cysteine proteases, respectively, are involved in antigen degradation. We have analyzed the antigen-presenting properties of cells derived from mice deficient in either Cat B or Cat D. Although the absence of these proteases provoked a modest shift in the efficiency of presentation of some antigenic determinants, the overall capacity of Cat B-/- or Cat D-/- antigen-presenting cells was unaffected. Degradation of Ii proceeded normally in Cat B-/- splenocytes, as it did in Cat D-/- cells. We conclude that neither Cat B nor Cat D are essential for MHC class II-mediated antigen presentation.

Synergy of CD95 ligand and teniposide: no role of cleavable complex formation and enhanced CD95 expression

Teniposide (VM26) enhanced the anti-glioma activity of the cytotoxic cytokine, CD95 ligand. Synergy was observed at concentrations of teniposide that were insufficient for cleavable DNA topoisomerase II complex formation. CD95 ligand did not modulate the formation or removal of such complexes after teniposide treatment. These processes were also unaffected by ectopic expression of bcl-2. Teniposide enhanced CD95 expression in a glioma cell line with wild-type p53 (LN-229) but not in two p53 mutant cell lines (T98G, LN-308). Forced expression of a transdominant negative p53 mutant prevented the teniposide induced augmentation of CD95 expression in LN-229 cells but did not prevent the synergy of CD95 ligand and teniposide. Teniposide did not alter CD95 ligand expression, and forced expression of CD95 did not modulate sensitivity to VM26. Thus, teniposide-induced DNA lesions and alterations in CD95 or CD95 ligand are not necessary for teniposide-induced sensitization of human malignant glioma cells to CD95-mediated apoptosis.

Taxol-mediated augmentation of CD95 ligand-induced apoptosis of human malignant glioma cells: association with bcl-2 phosphorylation but neither activation of p53 nor G2/M cell cycle arrest

The anti-tumour alkaloid taxol shows strong cytotoxic and antiproliferative activity in two human malignant glioma cell lines, T98G and LN-229. CD95 (Fas/APO-1) ligand is a novel cytotoxic cytokine of the tumour necrosis factor (TNF) family that exerts prominent antiglioma activity. At clinically relevant taxol concentrations of 5-100 nM, taxol and CD95 ligand showed significant synergistic cytotoxicity and growth inhibition. High concentrations of taxol induced G/M cell cycle arrest in both cell lines. The synergy of taxol and CD95 ligand was independent of cell cycle effects of taxol as synergy was achieved at much lower taxol concentrations than G2/M arrest and as cell cycle effects of taxol were unaffected by co-exposure to CD95 ligand. Similarly, high concentrations of taxol were required to induce p53 activity in the p53 wild-type cell line LN-229. This effect was not modulated by CD95 ligand, suggesting that synergy is also independent of p53 activation. However, taxol induced a mobility shift of the bcl-2 protein on immunoblot analysis, indicative of bcl-2 phosphorylation. Bcl-2 phosphorylation on serine was confirmed by immunoprecipitation and phosphoserine immunoblot analysis. Considering (1) that phosphorylation of bcl-2 interferes with its heterodimerization with bax and (2) the inhibition of CD95-mediated apoptosis by bcl-2, we propose that taxol sensitizes malignant glioma cells to CD95 ligand by increasing the functional bax/bcl-2 rheostat in favour of bax and thus cell death.

Epidemiology of HIV-1 infection in rural Georgia: demographic trends and analysis at the Medical College of Georgia

We have conducted a retrospective study of 100 HIV-infected patients enrolled in an AZT monotherapy clinical study at the Medical College of Georgia (MCG) in Augusta, Georgia. When compared to the national trends, our results confirm previous studies that describe an overall increase in the burden of HIV infections among blacks, and, in particular, black women in the rural Southeast. In our cohort, infections due to homosexual contact accounted for approximately 40% of all cases while heterosexual contact and intravenous drug use (IDU) comprised 33% and 13%, respectively. Infections attributable to all other risk factors accounted for the remaining 14%. Relative to national surveillance data, we observed an increase in the prevalence of HIV infections among blacks, and heterosexually acquired infections, particularly among black women. Our analysis illustrates the dynamic nature of the current U.S. epidemic which appears to be shifting both in terms of its demographic and epidemiological profile. These data may indicate that national surveillance data may not reflect the dynamic nature of current demographic trends in HIV incidence, particularly as evidenced in the rural Southeast. This suggests that hospital or laboratory based cross-sectional studies, like ours, that analyze demographic variables of HIV-infected clinic attendees may be necessary to more accurately assess the leading edge of the HIV epidemic in rural, non-metropolitan areas.

PK/PD simulations as a tool for rational design of clinical dosage regimens: an example with Fradafiban

In clinical studies, pharmacodynamic effects should be achieved, e.g. maintenance of certain effects with reversibly acting drugs. Available data base for early phase II studies is frequently kinetics in healthy volunteers from phase I studies and pharmacodynamic effects from in vivo or ex vivo data. Using the fibrinogen receptor antagonist Fradafiban as an example, a procedure to achieve rational dosage regimens is described. Applied methods were: curve fitting of plasma concentrations obtained in phase I studies, correlation of fibrinogen receptor occupancy (FRO) to plasma concentrations using a sigmoid Emax model with Hill coefficient for PK/PD correlation, simulation of time course of FRO for various dosage regimens, using estimates for variability from PK and PD data in order to estimate not only mean values but also expected range of FRO. In a phase II study with Fradafiban administered intravenously, therapeutically active plasma levels had to be achieved rapidly and maintained over 24 hours employing a simple infusion regimen in 20 patients and 3 dose groups. For the target dose, a FRO of 80% should be achieved in most patients. Using the tools mentioned above, a rapid initial infusion rate of 10 mg over 30 minutes, followed by a maintenance infusion of 30 mg for the remaining 23.5 hours for the target dose resulted in a median predicted FRO of 82%. For the lower dose, a 5/15 mg infusion over 0.5/23.5 hours, achieving a predicted FRO of 68% was used and the upper dose (15/45 mg) resulted in 87% FRO. Median experimental results were 84% FRO for the target dose and 73% and 88%, respectively, for the lower and upper dose. As these results fit reasonably well to the predictions, it can be concluded that kinetics in the mostly elderly patients is similar to kinetics in healthy young volunteers. Furthermore, FRO in patients is nearly identical to that in spiked human plasma. Taken together, it could be proven that PK/PD methods are a useful tool for design of clinical studies of Fradafiban.

Human autoreactive and foreign antigen-specific T cells resist apoptosis induced by soluble recombinant CD95 ligand

Mature T cells are susceptible to activation-induced cell death in the periphery. Activation-induced cell death is thought to involve CD95/CD95 ligand interactions in vivo. Here we report that stimulated, CD45RO+ human T cell lines specific for myelin basic protein or tetanus toxoid from multiple sclerosis patients and healthy individuals resist apoptosis induced by soluble recombinant CD95 ligand in vitro. In contrast, the same CD95 ligand effectively kills Jurkat T lymphoma and human malignant glioma cells. The resistance of the T cell lines is not due to a lack of CD95 expression at the cell surface and is not overcome by coexposure to CD95 ligand and inhibitors of RNA or protein synthesis. The expression level of BCL-2 is lower in Jurkat than in Ag-specific T cells. After exposure to soluble CD95 ligand, Jurkat T cells, but not Ag-specific T cells, exhibit loss of BCL-2 and BCL-X expression whereas BAX expression is not affected. Surprisingly, Ag-specific T cells are rather sensitive to CD95 ligand expressed at the cell surface of N2A neuroblastoma cells. Accessory molecules expressed by the CD95 ligand-expressing effector cell are dispensable for apoptosis since the T cells are equally sensitive to agonistic APO-1 Ab. Further studies are required to determine whether resistance to soluble CD95 ligand-mediated apoptosis is a possible escape mechanism for T cells from peripheral deletion that may have relevance for autoimmune disorders.

Human autoreactive and foreign antigen-specific T cells resist apoptosis induced by soluble recombinant CD95 ligand

Mature T cells are susceptible to activation-induced cell death in the periphery. Activation-induced cell death is thought to involve CD95/CD95 ligand interactions in vivo. Here we report that stimulated, CD45RO+ human T cell lines specific for myelin basic protein or tetanus toxoid from multiple sclerosis patients and healthy individuals resist apoptosis induced by soluble recombinant CD95 ligand in vitro. In contrast, the same CD95 ligand effectively kills Jurkat T lymphoma and human malignant glioma cells. The resistance of the T cell lines is not due to a lack of CD95 expression at the cell surface and is not overcome by coexposure to CD95 ligand and inhibitors of RNA or protein synthesis. The expression level of BCL-2 is lower in Jurkat than in Ag-specific T cells. After exposure to soluble CD95 ligand, Jurkat T cells, but not Ag-specific T cells, exhibit loss of BCL-2 and BCL-X expression whereas BAX expression is not affected. Surprisingly, Ag-specific T cells are rather sensitive to CD95 ligand expressed at the cell surface of N2A neuroblastoma cells. Accessory molecules expressed by the CD95 ligand-expressing effector cell are dispensable for apoptosis since the T cells are equally sensitive to agonistic APO-1 Ab. Further studies are required to determine whether resistance to soluble CD95 ligand-mediated apoptosis is a possible escape mechanism for T cells from peripheral deletion that may have relevance for autoimmune disorders.

Chemotherapy of human malignant glioma: prevention of efficacy by dexamethasone?

Steroids are commonly administered for the control of edema, mass effect, and side effects from therapy to patients with malignant glioma who are receiving radiotherapy and chemotherapy. Here, we report that therapeutic concentrations of dexamethasone (DEX) attenuate cytotoxicity and growth inhibition of human malignant glioma cells induced by exposure to several chemotherapeutics, including ACNU, VM-26, vincristine, cytarabine, methotrexate, and adriamycin. DEX-mediated cytoprotection is not linked to DEX effects on glioma cell proliferation. However, the cytoprotective effects of DEX appeared to be more prominent in cell lines with wild-type p53 status (n = 2) than in p53 mutant cell lines (n = 3). Further, DEX-mediated rescue from chemotherapy does not directly involve Bcl-2 family proteins since DEX failed to change the expression of Bcl-2 or Bax proteins and since bcl-2 gene transfer-mediated cytoprotection was not redundant with the effects of DEX. DEX thus appears to control a common, bcl-2-independent death pathway in glioma cells that is not limited to specific drug actions. Chemotherapy is usually given as an elective, adjuvant treatment to glioma patients in stable condition who can tolerate steroid withdrawal. To maximize therapeutic efficacy, steroids should be withdrawn from glioma patients prior to chemotherapy.

The genes of the lysosomal cysteine proteinases cathepsin B, H, L, and S map to different mouse chromosomes

The mouse genes for the lysosomal cysteine proteinases cathepsin B, H, L, and S were mapped to Chromosomes (Chrs) 14, 9, 13, and 3, respectively. Two of the DNA probes used in this study detected an additional, independently segregating locus. The cathepsin B-specific probe hybridized to a locus on Chr 2, and the cathepsin H probe to a locus on the X Chr. These loci either correspond to pseudogenes or to cathepsin B- and cathepsin H-related genes. The four cysteine proteinases mapped in this study lie within known regions of conserved synteny between mouse and human chromosomes, when compared with the corresponding positions of their human homologs. Assuming that the genes of the cysteine proteinase gene family arose from a common ancestral gene, our results suggest that these four cysteine proteinases had been dispersed over different chromosomes before separation of mouse and human in evolution.

Immunochemotherapy of malignant glioma: synergistic activity of CD95 ligand and chemotherapeutics

Malignant glioma cells are susceptible to CD95(Fas/APO-)-mediated apoptosis triggered by agonistic antibody. Here we examined the proapoptotic effects of the natural CD95 ligand, a cytotoxic cytokine homologous to tumor necrosis factor, on malignant glioma cell lines LN-229, LN-308 and T98G. We assessed whether glioma cell killing is synergistically enhanced by cotreatment with CD95 ligand and chemotherapeutic agents, including doxorubicin, carmustine, vincristine, etoposide, teniposide, 5-fluorouracil and cytarabine. Synergy was examined at low concentrations of cytotoxic drugs and CD95 ligand with a defined effect level (IC15). Short-term-cytotoxicity assays showed prominent killing of the glioma cells by CD95 ligand but not by the drugs at relevant concentrations. CD95 ligand induced apoptosis in the acute toxicity paradigm was augmented by doxorubicin and vincristine. Growth-inhibition assays revealed prominent synergy between CD95 ligand and all drugs examined. The best synergy was obtained with CD95 ligand and doxorubicin, vincristine or teniposide. The strong synergistic antiproliferative effects were observed at much lower concentrations of CD95 ligand and cytotoxic drugs than the moderate synergistic acute cytotoxic effects. All cell lines examined express the Bcl-2 protein. LN-229 has partial wild-type p53 activity. T98G has mutant p53, LN-308 has a deleted p53 gene and lacks p53 protein expression. Thus, synergistic effects of CD95 ligand and cytotoxic drugs were observed in cell lines exhibiting two features thought to play a role in the chemoresistance of human malignant glioma cells: loss of wild-type p53 activity and acquisition of bcl-2 expression. Ectopic expression of murine bcl-2 conferred partial protection from CD95 ligand and drugs when administered alone but did not interfere with the mechanisms underlying the synergistic effects of CD95 ligand and chemotherapeutic drugs.

A review of the clinical pharmacokinetics of meloxicam

Meloxicam is a new preferential cyclooxygenase-2 (COX-2) inhibitor currently for the treatment of osteoarthritis and rheumatoid arthritis. Its pharmacokinetic profile is characterized by a prolonged and almost complete absorption and the drug is > 99.5% bound to plasma proteins. Meloxicam is metabolized to four biologically inactive main metabolites, which are excreted in both urine and faeces. The elimination half-life (t1/2) of meloxicam is approximately 20 h. This is reflected in a total plasma clearance (CL) of 0.42-0.48 1/h. Steady-state plasma concentrations are achieved within 3-5 days. The pharmacokinetic parameters of meloxicam are linear over the dose range 7.5-30 mg and bioequivalence has been shown for a number of different formulations. No interactions were observed following the concomitant administration of food, cimetidine, antacid, aspirin, beta-acetyldigoxin, methotrexate, warfarin or furosemide. Neither hepatic insufficiency nor moderate renal dysfunction have any relevant effects on the pharmacokinetics of meloxicam and dosage adjustments in the elderly are not required.

Attenuation of shock-induced inflammation in the rat liver depends on the time of TNF-alpha inhibition

The relevance of tumor necrosis factor-alpha (TNF-alpha) inducing early inflammatory reactions in the liver after hemorrhagic shock, for example, leukocyte adhesion, has been well described. This study evaluated the anti-inflammatory effects of a monoclonal antibody against TNF-alpha (TN3.19.12) in terms of the time of application, namely, prior to shock induction, at the time of resuscitation, and after resuscitation. The hepatic microcirculation was investigated by intravital fluorescence microscopy in female Sprague-Dawley rats undergoing severe hemorrhagic shock for 60 min and subsequent resuscitation. TN3.19.12 or placebo was given in a randomized and blinded manner either 60 min prior to shock induction, 1 min prior to resuscitation, or 15 min after the onset of resuscitation. The number of firmly adherent leukocytes in the livers of treated animals depended on the time of application of TN3.19.12. Leukocyte adhesion was significantly reduced when TN3.19.12 was given prior to shock induction or at the time of resuscitation and was less effective when administered after the onset of resuscitation. The results further confirm that TNF-alpha initiates very early pathological leukocyte adhesion in the liver 5 h following shock. Inhibition of leukocyte adhesion after shock, however, depends strongly on the time of TNF-alpha blocking. While TN3.19.12 prior to shock induction resulted in most effective attenuation, only very early treatment allowed limitation of posttraumatically increased leukocyte adhesion.

Pharmacokinetic-pharmacodynamic and metabolite modeling with TopFit

Two examples illustrating the ease of use and powerful data fitting and simulation techniques provided by the validated program TopFit 2.0 for the PC are presented. In the first, kinetics of parent compound and metabolite for (+) and (-) enantiomers of a racemic compound X were determined during a Phase III clinical study. Four data sets were fitted simultaneously for each patient. The model could be defined by the user without programming differential equations. The fit results indicated enantiomer specific kinetics for the metabolite but not for parent compound. In the second example, a model with nonlinear elimination and an Emax-effect function was used to simultaneously fit data from six doses of compound Y in a Phase I study. The fitted parameters predicted the feasibility of a twice-daily dose regimen despite a very short plasma half-life of the compound. In conclusion, TopFit provides rapid and cost-effective support in analysis and design of clinical trials.