Pancreatic carcinoma cell lines reflect frequency and variability of cancer stem cell markers in clinical tissue.

BACKGROUND: Pancreatic cancer is one of the most deadly malignancies with insufficient therapeutic options and poor outcome. Cancer stem cells (CSCs) are thought to be responsible for progression and therapy resistance. We investigated the potential of pancreatic cell lines for CSC research by analyzing to what extent they contain CSC populations and how representative these are compared to clinical tissue. METHODS: Six pancreatic cancer cell lines were analyzed by flow cytometry for CD326, CD133, CD44, CD24, CXCR4 and ABCG2. Subsequently, 70 primary pancreatic tissues were evaluated for CD326, CD133 and CD44 by immunohistochemistry. RESULTS: All the cell lines but one showed a stable expression pattern throughout biological replicates. Marker expression in clinical tissue of CD44 distinguished normal patients from pancreatic carcinoma patients with a sensitivity of 50% at 80% specificity and metastasized from nonmetastasized carcinomas with 69% sensitivity at 100% specificity. CONCLUSIONS: Our results indicate a link between elevated CD44 expression, malignancy and metastasis of pancreatic tissue. Furthermore, individual pancreatic cell lines show a substantial amount of cells with CSC properties which is comparable with interpatient variability detected in primary tissue. These pancreatic cancer cell lines could thus serve for urgently needed pharmacological CSC in vitro research.

Biphasic kinetics of peripheral blood T cells after triple combination therapy in HIV-1 infection: a composite of redistribution and proliferation.

The origin of CD4+ T cells reappearing in the blood following antiretroviral therapy in human immunodeficiency virus type-1 (HIV-1) infection is still controversial. Here we show, using mathematical modeling, that redistribution of T cells to the blood can explain the striking correlation between the initial CD4+ and CD8+ memory T-cell repopulation and the observation that 3 weeks after the start of treatment memory CD4+ T-cell numbers reach a plateau. The increase in CD4+ T cells following therapy most likely is a composite of initial redistribution, accompanied by a continuous slow repopulation with newly produced naive T cells.

Phenotypic indications that human sweat glands are a rich source of nestin-positive stem cell populations.

BACKGROUND: We have recently shown that the expression of nestin, a progenitor/stem cell marker protein, is localized in different mesenchymal compartments in human skin including the sweat gland stroma. OBJECTIVES: As other exocrine glands are recognized sources of multipotent stem cell populations with potential for multilineage differentiation, it was our aim to isolate, expand and characterize glandular stem cells from human sweat glands. METHODS: Isolation of human sweat glands was based on mechanical and enzymatic digestion of axillary skin. Cultivation was performed on collagen-coated cell culture dishes and the resulting cell population was investigated at the protein and mRNA level. RESULTS: Outgrowing cells of isolated sweat glands showed a high-proliferation activity and were characterized by nestin expression in more than 80% of the cells. These sweat gland stem cells could be maintained in culture for long periods of time and showed spontaneous differentiation into cells representative of the different germ layers. CONCLUSIONS: This pilot study provides the first, simple protocol for the isolation of adult human nestin-positive stem cells from the sweat gland mesenchyme, which promises to provide an easily accessible and abundantly available, autologous source of multipotent stem cells for cell-based regenerative medicine applications.

Kinetics of response in lymphoid tissues to antiretroviral therapy of HIV-1 infection.

In lymphoid tissue, where human immunodeficiency virus-type 1 (HIV-1) is produced and stored, three-drug treatment with viral protease and reverse transcriptase inhibitors markedly reduced viral burden. This was shown by in situ hybridization and computerized quantitative analysis of serial tonsil biopsies from previously untreated adults. The frequency of productive mononuclear cells (MNCs) initially diminished with a half-life of about 1 day. Surprisingly, the amount of HIV-1 RNA in virus trapped on follicular dendritic cells (FDCs) decreased almost as quickly. After 24 weeks, MNCs with very few copies of HIV-1 RNA per cell were still detectable, as was proviral DNA; however, the amount of FDC-associated virus decreased by >/=3.4 log units. Thus, 6 months of potent therapy controlled active replication and cleared >99.9 percent of virus from the secondary lymphoid tissue reservoir.

Sexual transmission and propagation of SIV and HIV in resting and activated CD4+ T cells.

In sexual transmission of simian immunodeficiency virus, and early and later stages of human immunodeficiency virus-type 1 (HIV-1) infection, both viruses were found to replicate predominantly in CD4(+) T cells at the portal of entry and in lymphoid tissues. Infection was propagated not only in activated and proliferating T cells but also, surprisingly, in resting T cells. The infected proliferating cells correspond to the short-lived population that produces the bulk of HIV-1. Most of the HIV-1-infected resting T cells persisted after antiretroviral therapy. Latently and chronically infected cells that may be derived from this population pose challenges to eradicating infection and developing an effective vaccine.

Interaction of LL-37 with model membrane systems of different complexity: influence of the lipid matrix.

As the main difference between bacterial and mammalian cell membranes is their net charge, the focal point of consideration in many model membrane experiments with antimicrobial peptides is lipid headgroup charge. We studied the interaction of the human multifunctional peptide LL-37 with single phospholipid monolayers, bilayers, and bilayers composed of binary mixtures of the four phospholipid species predominantly used in model membrane experiments (phosphatidylcholine, phosphatidylethanolamine, phosphatidylglycerol, and phosphatidylserine). We found that 1), the effects on single lipid monolayers are not comparable to those on the corresponding bilayers; 2), there are four different effects of LL-37 on bilayers of the four lipids; 3), the preference of LL-37 for the specific lipids is roughly inversely related to chain packing density; and 4), in the binary lipid mixtures, one lipid-and not necessarily the charged one--generally governs the mode of lipid/peptide interaction. Thus, our results show that lipid net charge is not the decisive factor determining the membrane-perturbing mechanism of LL-37, but only one of several parameters, among them packing density, the ability to form intermolecular H-bonds, and lipid molecular shape, which emphasizes how profoundly the choice of the model system can influence the outcome of a study of lipid/peptide interaction.

A context-learning pharmacotherapy program for preclinical medical students leads to more rational drug prescribing during their clinical clerkship in internal medicine.

The irrational prescribing of drugs seems to be a general problem in medical practice, occasionally leading to serious consequences. In order to improve the drug prescribing performance of medical students, a compulsory context-learning pharmacotherapy module was implemented in 1998 in the medical curriculum of 2nd-4th-year medical students at theVU University Medical Center (VUmc), Amsterdam, The Netherlands. As part of this program, preclinical medical students are taught how to select, prescribe, and evaluate a drug regimen rationally. The aim of this study was to investigate the effect of this preclinical pharmacotherapy program on the quality of rational prescribing during the ensuing clinical clerkship of these students in internal medicine. The results of this study indicate that preclinical context-learning in pharmacotherapy leads to the use of more rational prescribing modalities by medical students during their ensuing clinical clerkship in internal medicine. This effect was obtained not only with respect to the clinical topics in which training had been given as part of the pharmacotherapy curriculum, but also for other disease situations that the students dealt with. This implies that students not only remember the specific information they have learned during the training, but are also able to apply the acquired skills in new situations (transfer effect).

Influence of rapamycin on rat macrophage viability and chemotaxis toward allogenic pancreatic islet supernates.

The aim of this work was to evaluate the effects of rapamycin on rat macrophage viability and chemotaxis toward allogereic pancreatic islet supernates. Macrophages were isolated from rats by peritoneal lavage at 3 days after intraperitoneal injection of thioglycolate. Macrophage viability was studied after 7 days of culture by Cell Titer assays in the presence of rapamycin at 0.1, 1, and 10 ng/mL (n = 6). After 48 hours of culture, pancreatic rat islet supernates were studied for there chemotactic properties toward freshly isolated macrophages in the presence of rapamycin at 0.1, 1, and 10 ng/mL. Chemotaxis was expressed as a migration index defined as the number of macrophages attracted by the test solution (islet supernate +/- rapamycin)/number of macrophages attracted by the supernate (n = 6). After 3 days of culture, macrophage viability decreased significantly by 22%, 36%, and 32% in the presence of 0.1, 1, and 10 ng/mL rapamycin, respectively (P = .008). Macrophage viability remained stable at about 70% after 7 days of culture. In the presence of islet supernates, macrophage migration increased two-fold compared with those obtained by culture medium. Rapamycin did not influence macrophage migration toward culture medium. However, the drug significantly reduced the migration of macrophages toward islet supernates from 2 +/- 0.6 to 0.9 +/- 0.4, 0.7 +/- 0.3, or 0.8 +/- 0.4 in the presence of 0.1, 1, or 10 ng/mL rapamycin, respectively (P = .04). Rapamycin decreased the survival of cultured rat macrophages and their migration toward allogenic islet supernates. These results suggested that, besides its anti-proliferative effect on T cells, rapamycin reduced macrophage attraction to the graft site.

Activating KIR Haplotype Influences Clinical Outcome Following HLA-Matched Sibling Hematopoietic Stem Cell Transplantation.

Natural killer cells are thought to influence the outcome of hematopoietic stem cell transplant (HSCT), impacting on relapse, overall survival, graft versus host disease and the control of infection, in part through the complex interplay between the large and genetically diverse killer immunoglobulin-like receptor (KIR) family and their ligands. This study examined the relationship between KIR gene content and clinical outcomes including the control of opportunistic infections such as cytomegalovirus in the setting of human leucocyte antigen (HLA)-matched sibling HSCT in an Australian cohort. The presence of the KIR B haplotype which contain more activating receptors in the donor, in particular centromeric B haplotype genes (Cen-B), was associated with improved overall survival of patients with acute myeloid leukemia (AML) undergoing sibling HSCT and receiving myeloablative conditioning. Donor Cen-B haplotype was also associated with reduced acute graft versus host disease grades II-IV whereas donor telomeric-B haplotype was associated with decreased incidence of CMV reactivation. In contrast, we were not able to demonstrate a reduced rate of relapse when the donor had KIR Cen-B, however relapse with a donor Cen-A haplotype was a competing risk factor to poor overall survival. Here we show that the presence of donor activating KIR led to improved outcome for the patient, potentially through reduced relapse rates and decreased incidence of acute GvHD translating to improved overall survival. This article is protected by copyright. All rights reserved.

Immunological abnormalities in human immunodeficiency virus (HIV)-infected asymptomatic homosexual men. HIV affects the immune system before CD4+ T helper cell depletion occurs.

To investigate the effect of persistent HIV infection on the immune system, we studied leukocyte functions in 14 asymptomatic homosexual men (CDC group II/III) who were at least two years seropositive, but who still had normal numbers of circulating CD4+ T cells. Compared with age-matched heterosexual men and HIV-negative homosexual men, the CD4+ and CD8+ T cells from seropositive men showed decreased proliferation to anti-CD3 monoclonal antibody and decreased CD4+ T-helper activity on PWM-driven differentiation of normal donor B cells. Monocytes of HIV-infected homosexual men showed decreased accessory function on normal T cell proliferation induced by CD3 monoclonal antibody. The most striking defect in leukocyte functional activities was observed in the B cells of HIV-infected men. B cells of 13 out of 14 seropositive men failed to produce Ig in response to PWM in the presence of adequate allogeneic T-helper activity. These findings suggest that HIV induces severe immunological abnormalities in T cells, B cells, and antigen-presenting cells early in infection before CD4+ T cell numbers start to decline. Impaired immunological function in subclinically HIV-infected patients may have clinical implications for vaccination strategies, in particular the use of live vaccines in groups with a high prevalence of HIV seropositivity.

Selective inhibition of syncytium-inducing and nonsyncytium-inducing HIV-1 variants in individuals receiving didanosine or zidovudine, respectively.

By studying changes in the clonal composition of HIV-1 populations during the first weeks of zidovudine (ZDV) treatment before the development of ZDV resistance-conferring mutations, we demonstrated previously a selective inhibition of nonsyncytium-inducing (NSI) HIV-1, even when present as coexisting population in individuals also harboring syncytium-inducing (SI) HIV-1. In this study, we observed the opposite in individuals receiving didanosine (ddI) treatment. In these individuals (n = 7) a median -0.98 log change (range -1.55-0.08) in infectious cellular SI load was observed, whereas the coexisting NSI load was only minimally affected (median -0.15 log, range -1.27-0.50; P = 0.03). The virus phenotype-dependent treatment responses were independent of the clonal composition of HIV-1 populations at baseline. Individuals treated with a combination of ZDV and ddI revealed an equal decline of both NSI and SI infectious cellular load (n = 4; NSI: median -1.55 log, range -2.19 to -1.45; SI: median -1.47 log, range -1.81 to -0.86; P = 0.56). To test the hypothesis that the previously reported optimal activation of ZDV and ddI in activated and resting T cells, respectively, in combination with the differential T cell tropism of NSI and SI HIV-1 is the basis for the observed virus phenotype specific efficacy of nucleoside analogs, we studied the effect of treatment with a protease inhibitor that does not require intracellular activation. Individuals receiving ritonavir (n = 4) indeed showed equal declines in NSI and SI infectious cellular load (NSI: median -2.37 log, range -2.59 to -2.16; SI: median -2.82 log, range -3.14 to -2.50; P = 0.25). Our data suggest HIV-1 phenotype as an additional parameter in the design of optimal treatment regimens.

Implantation of cultured thymic fragments in patients with acquired immunodeficiency syndrome.

Cultured thymic fragments were implanted in one patient with acquired immunodeficiency syndrome (AIDS)-related complex (ARC) and in eight AIDS patients with opportunistic infections (OIs, four patients), Kaposi's sarcoma (KS, two patients), or both (two patients). Thereafter, objective clinical improvement was noted in one patient with OI, and a stable symptom-free condition was observed in the ARC patient and in two other patients with OIs. However, the ARC patient and two of the three patients with OIs developed infections three to six months after implantation. A fourth case of OI and the patients with KS showed progression of the disease. Peripheral blood investigations for counts of total leukocytes, lymphocytes, and T-lymphocyte subsets as well as for lymphocyte stimulation with mitogens showed no changes interpretable as an improvement of the cellular immune deficiency status. We conclude that cultured thymic fragments have no distinct in vivo effect on the course of AIDS, except for a temporary clinical improvement or a period of stable condition in some patients with OIs.

Persistence of human immunodeficiency virus antigenemia in patients with the acquired immunodeficiency syndrome treated with a reverse transcriptase inhibitor, suramin. Ten-patient case-control study.

Ten homosexual men with the acquired immunodeficiency syndrome were included in a serologic follow-up study (duration, 40 weeks) of human immunodeficiency virus (HIV) antigenemia. Five of these men were treated with the reverse transcriptase inhibitor, suramin, for a period of 19 to 37 weeks. In contrast with reported changes in HIV antigen levels after treatment with zidovudine, HIV antigenemia persisted in the suramin-treated group, as well as in the untreated group. No clinical or immunologic improvement was seen in either group within the observation period. These data add evidence to the notion that monitoring HIV antigen levels helps to assess the efficacy of antiviral therapy.

Limited patient adherence to highly active antiretroviral therapy for HIV-1 infection in an observational cohort study.

BACKGROUND: Adherence to highly active antiretroviral therapy (HAART) for human immunodeficiency syndrome type 1 (HIV-1) infection is essential to sustain viral suppression and prevent drug resistance. We investigated adherence to HAART among patients in a clinical cohort study. METHODS: Patients receiving HAART had their plasma concentrations of protease inhibitors or nevirapine measured and completed a questionnaire on adherence. We determined the percentage of patients who reported taking all antiretroviral medication on time and according to dietary instructions in the past week. Drug exposure was compared between patients reporting deviation from their regimen and fully adherent patients. Among patients who received HAART for at least 24 weeks, we assessed the association between adherence and virologic outcome. RESULTS: A total of 224 of 261 eligible patients completed a questionnaire. Forty-seven percent reported taking all antiretroviral medication on time and according to dietary instructions. Patients who reported deviation from their regimen showed lower drug exposure compared with fully adherent patients (median concentration ratio, 0.81 vs 1.07; P =.001). Among those receiving HAART for at least 24 weeks, patients reporting deviation from their regimen were less likely to have plasma HIV-1 RNA levels below 500 copies/mL (adjusted odds ratio, 4.0; 95% confidence interval, 1.4-11.6) compared with fully adherent patients. CONCLUSIONS: Only half of the patients took all antiretroviral medication in accordance with time and dietary instructions in the preceding week. Deviation from the antiretroviral regimen was associated with decreased drug exposure and a decreased likelihood of having suppressed plasma HIV-1 RNA loads. Patient adherence should remain a prime concern in the management of HIV-1 infection.

Management of cytomegalovirus disease.

AIM: To review the estimated incidence of cytomegalovirus (CMV) disease, its diagnosis and currently accepted treatments and those under investigation. CMV DISEASE IN PATIENTS WITH HIV INFECTION: The most frequently occurring manifestation of CMV disease is retinitis, occurring in approximately 20-40% of patients. Oesophagitis and generalized infection are also common. DIAGNOSIS: At present, diagnosis relies on specific histopathology as serology is unreliable and CMV culture lacks sensitivity and specificity. Assessment of the presence of CMV-specific proteins and polymerase chain reaction assays of CMV DNA may prove useful. TREATMENT: Intravenous ganciclovir and foscarnet are equally effective for the treatment of CMV disease, but ganciclovir is generally regarded as the primary treatment option due to its relative ease of administration. Combination therapy with these agents is also effective in the treatment of CMV retinitis. As well as patients with sight-threatening retinitis, patients with peripheral retinitis benefit from immediate treatment. Local treatment with a ganciclovir implant or intravitreal injection is effective, but does not provide protection against ocular complications, infection of the contralateral eye and extraocular disease. Oral ganciclovir is virtually as effective as intravenous administration for secondary prophylaxis versus maintenance treatment for CMV retinitis with the advantage of a more favourable adverse-effect profile. CONCLUSIONS: Intravenous ganciclovir and foscarnet are equally effective in the treatment of CMV disease. Oral ganciclovir is effective in secondary prophylaxis and provides a welcome alternative to intravenous maintenance treatment.

Cytomegalovirus retinitis in AIDS patients: a comparative study of intravenous and oral ganciclovir as maintenance therapy.

OBJECTIVES: To compare the safety and efficacy or oral ganciclovir with intravenous ganciclovir for the maintenance therapy of cytomegalovirus (CMV) retinitis in AIDS patients. DESIGN: Multicenter, randomized, open-label study, with both masked and unmasked ophthalmic assessments. METHODS: Patients with AIDS and stable CMV retinitis were randomized after an induction course of intravenous ganciclovir (5 mg/kg twice daily) to receive maintenance therapy with oral ganciclovir (500 mg six times daily) or intravenous ganciclovir (5 mg/kg once daily). MAIN OUTCOME MEASURE: The primary endpoint of the study was time to progression of CMV retinitis from the start of maintenance therapy. RESULTS: The mean time to progression, evaluated by funduscopy was 109 days for the intravenous group, and 86 days for the oral group (P = 0.02). The masked photographic assessment revealed shorter time to progression for both oral and intravenous groups, as compared with funduscopy data, and showed no significant difference between the two treatment groups: 62 days for intravenous ganciclovir and 51 days for oral ganciclovir (P = 0.15). Diarrhea and neutropenia were the most frequent reported events in both groups, with the incidence of sepsis more than double in the intravenous compared with the oral ganciclovir group (3 versus 8.5%). CONCLUSIONS: Oral ganciclovir offers a reasonable alternative to intravenous ganciclovir for the maintenance therapy of CMV retinitis in AIDS patients.

Decreased exposure to saquinavir in HIV-1-infected patients after long-term antiretroviral therapy including ritonavir and saquinavir.

OBJECTIVE: To explore whether steady-state plasma pharmacokinetics of ritonavir and saquinavir change during long-term treatment in HIV-1-infected patients on antiretroviral treatment including ritonavir and saquinavir. METHODS: The pharmacokinetics of ritonavir and saquinavir were assessed during an 8-h period on two occasions in six HIV-1 infected patients on stable twice daily treatment with ritonavir 400 mg, saquinavir 400 mg and stavudine 40 mg with or without lamivudine 150 mg twice daily. RESULTS: The first study day was 4-12 months (median 7 months) after the start of the current regimen. The second study day was 9-15 months (median 10 months) later. No significant differences were observed for the ritonavir pharmacokinetics between the first and second study day. However, median change in plasma trough level of saquinavir between the two study days was -30% (range -79 to +11%; P = 0.06). Median change in maximum plasma concentration was -40% (range -62 to +34%; P = 0.09). The median change in area under the plasma concentration versus time curve over 0-8 h was -33% (range -53 to +21%; P = 0.06). CONCLUSION: The exposure to saquinavir decreased over time in HIV-infected patients on stable antiretroviral therapy. These data suggest that regular monitoring of plasma drug concentrations should become part of routine patient care even in apparently compliant patients.

Therapy for cytomegalovirus polyradiculomyelitis in patients with AIDS: treatment with ganciclovir.

Six AIDS patients with progressive cytomegalovirus (CMV) polyradiculomyelitis were treated with ganciclovir in an open study. The diagnosis was based on the presence of a distinct clinical syndrome with progressive flaccid paraparesis, preserved proprioception and urinary retention with specific cerebrospinal fluid (CSF) findings. Ganciclovir therapy, 5-10 mg/kg per day, instituted 3-6.5 weeks after onset of symptoms, was ineffective in four patients with severe paraparesis. One patient developed CMV polyradiculomyelitis while receiving ganciclovir and further deteriorated during foscarnet therapy. One patient however, showing minor paresis of one leg, improved after institution of ganciclovir therapy 1 week after onset of symptoms. It is concluded that a presumptive diagnosis of CMV polyradiculomyelitis can be made on the basis of distinct clinical findings and CSF pleocytosis with predominance of polymorphonuclear leukocytes in patients with AIDS. Ganciclovir therapy does not appear to be beneficial for patients with advanced paresis in the doses used. Further investigations are needed in order to determine if early intervention with ganciclovir, when paresis is mild, or higher doses in advanced paresis, might be of some benefit.

Mycobacterium xenopi in HIV-infected patients: an emerging pathogen.

BACKGROUND: Mycobacterium xenopi is associated with pulmonary disease in patients with loss of local or general host defence. OBJECTIVES: To determine the occurrence of M. xenopi in our hospital during 1987-1992 and 1993-1996, as well as the association of M. xenopi with HIV infection in 1993-1996; to evaluate the clinical significance of M. xenopi in HIV-seropositive patients. DESIGN: Retrospective review of charts and classification of patients based on earlier definitions derived from the American Thoracic Society. SETTING: Tertiary hospital. PATIENTS: Patients with a positive isolate of M. xenopi from January 1987 until December 1996. MAIN OUTCOME MEASURES: During 1993 1996, a significant increase in the number of patients with M. xenopi was found compared with 1987-1992. Of 25 patients, 22 were HIV-seropositive. RESULTS: The HIV-seropositive patients were classified as having definite (n = 5), probable (n = 9) and unlikely disease (n = 8) due to M. xenopi. Symptoms, median CD4 cell count, treatment and outcome did not differ between these groups. CONCLUSIONS: M. xenopi is an emerging pathogen, especially in HIV-infected patients. The criteria of the American Thoracic Society for disease due to non-tuberculous mycobacteria do not seem applicable to M. xenopi in HIV-infected patients. We suggest that two positive cultures of M. xenopi and no other likely cause of symptoms present should be considered the criteria for diagnosis of M. xenopi disease in HIV-infected patients.

Rate of HIV-1 decline following antiretroviral therapy is related to viral load at baseline and drug regimen.

OBJECTIVES AND DESIGN: The dynamics uf viral decline following the initiation of antiretroviral treatment were studied in 29 HIV-1-infected patients participating in a two-arm trial comparing immediate (group A: ritonavir, zidovudine and lamivudine) and delayed (group B: ritonavir supplemented by zidovudine and lamivudine on day 21) triple therapy. Parameters underlying viral dynamics were estimated using mathematical models tailored to these treatment protocols. RESULTS: The decline in plasma HIV-1 density between day 0 and 21 was steeper in group A (-2.27+/- 0.46 log10) than group B (-1.87+/-0.56 log10). In a subset of patients amenable to full mathematical analysis, a short-lived productively infected cell compartment (producing approximately 97% of total virions) decayed with a half-life of 1.0-2.5 days, whereas a long-lived infected cell compartment decayed with a half-life of 18.8-32.8 days. Estimates for the time for the elimination of virus from these two cell populations ranged from 474 to 802 days. The rate of loss of productively infected CD4+ T cells was positively correlated with baseline viral load in group A and in the combined dataset. CONCLUSIONS: These results suggest that HIV-infected cell populations may have a faster turnover in patients with higher viral loads due to higher infection rate parameters, higher rates of virus production, or lower virus clearance rates.