Venetoclax, bendamustine, and rituximab in patients with relapsed or refractory NHL: a phase Ib dose-finding study.

Background: Venetoclax is a selective, potent inhibitor of the anti-apoptotic B-cell leukemia/lymphoma-2 protein approved for treatment of chronic lymphocytic leukemia. We conducted a dose-finding study of venetoclax in combination with bendamustine-rituximab (BR) in patients with relapsed/refractory non-Hodgkin's lymphoma (NHL). Patients and methods: BR was given for six cycles at standard doses. Intermittent and continuous oral venetoclax administration was explored at 50-1200 mg daily doses. Co-primary objectives included safety, pharmacokinetics (PKs), maximum-tolerated dose (MTD), and recommended phase II dose (RP2D); secondary objective was preliminary efficacy. Results: Sixty patients were enrolled: 32 with follicular lymphoma, 22 with diffuse large B-cell lymphoma, and 6 with marginal zone lymphoma. Nausea (70%), neutropenia (68%), diarrhea (55%), and thrombocytopenia (52%) were the most frequent adverse events (AEs). Most common grade 3/4 AEs were neutropenia (60%) and lymphopenia (38%). Serious AEs were reported in 24 patients; the most frequent were febrile neutropenia and disease progression (8% each). Five patients died from either disease progression (n = 4) or respiratory failure (n = 1). MTD was not reached; RP2D for venetoclax-BR combination was established as 800 mg daily continuously. Venetoclax PK exposure with and without BR was comparable. For all patients, overall response rate was 65%. Median duration of overall response, overall survival, and progression-free survival was 38.3 months [95% confidence interval (CI) 10.4-NR], not yet reached, and 10.7 months (95% CI 4.3-21.0), respectively. Conclusions: This study established the safety profile of venetoclax in combination with BR, and results demonstrated tolerability and preliminary efficacy of the combination. Additional follow-up is needed to better determine the future role of BR plus venetoclax in the treatment of relapsed/refractory B-cell NHL. Trial registered: Clinicaltrials.gov, NCT01594229.

International Working Group consensus response evaluation criteria in lymphoma (RECIL 2017).

In recent years, the number of approved and investigational agents that can be safely administered for the treatment of lymphoma patients for a prolonged period of time has substantially increased. Many of these novel agents are evaluated in early-phase clinical trials in patients with a wide range of malignancies, including solid tumors and lymphoma. Furthermore, with the advances in genome sequencing, new "basket" clinical trial designs have emerged that select patients based on the presence of specific genetic alterations across different types of solid tumors and lymphoma. The standard response criteria currently in use for lymphoma are the Lugano Criteria which are based on [18F]2-fluoro-2-deoxy-D-glucose positron emission tomography or bidimensional tumor measurements on computerized tomography scans. These differ from the RECIST criteria used in solid tumors, which use unidimensional measurements. The RECIL group hypothesized that single-dimension measurement could be used to assess response to therapy in lymphoma patients, producing results similar to the standard criteria. We tested this hypothesis by analyzing 47 828 imaging measurements from 2983 individual adult and pediatric lymphoma patients enrolled on 10 multicenter clinical trials and developed new lymphoma response criteria (RECIL 2017). We demonstrate that assessment of tumor burden in lymphoma clinical trials can use the sum of longest diameters of a maximum of three target lesions. Furthermore, we introduced a new provisional category of a minor response. We also clarified response assessment in patients receiving novel immune therapy and targeted agents that generate unique imaging situations.

In utero antidepressant exposure not associated with ADHD in the offspring: A case control sibling design.

Recent studies have reported an association between antidepressant (AD) use during pregnancy and the risk to develop attention-deficit/hyperactivity disorder (ADHD) in the offspring. However, the association might be confounded by risk factors in the pregnant parent. To control for unmeasured factors between pregnancies carried by the same parent, we set up a case-control sibling study using the University of Groningen prescription database IADB.nl. Children receiving medication for ADHD (cases) before the age of 16 years were matched to siblings not receiving such medication (controls). Exposure was defined as at least two prescriptions for any AD during pregnancy, i.e., the period of 39 weeks before the birth date of the offspring. Secondary analyses were performed to assess the effects of the degree of exposure (the amount of Defined Daily Doses) and the type of AD exposed to. Univariate and multivariate logistic regression was used to estimate odds ratios (ORs) with corresponding 95% confidence intervals (CI). In total, 2,833 children (1,304 cases and 1,529 controls) were included in the analysis. Exposure rate to ADs among cases and controls was 2.2% and 2.4%, respectively. After adjusting for the birth date of the child (as a proxy for the date of pregnancy), age of the pregnant parent at birth, use of psychostimulants, opioids, and antiepileptic drugs by the pregnant parent in the 15 months before birth of the child, an adjusted OR of 1.11 (95% CI 0.67-1.83) was found for the risk of ADHD in the offspring when exposed in utero to ADs. This indicates no increased risk of ADHD in offspring following in utero exposure to ADs. The secondary analyses revealed no statistically significant associations either. The present study provides further evidence that an association between in utero AD exposure and ADHD in offspring might not exist. This perceived association may be caused (at least partially) by confounding by indication. The extent to which depression in the pregnant parent could cause mental disorders such as ADHD in offspring, and the mechanisms involved, should be investigated in further studies.

Distinct gene signature revealed in white blood cells, CD4(+) and CD8(+) T cells in (NZBx NZW) F1 lupus mice after tolerization with anti-DNA Ig peptide.

Tolerizing mice polygenically predisposed to lupus-like disease (NZB/NZW F1 females) with a peptide mimicking anti-DNA IgG sequences containing MHC class I and class II T cell determinants (pConsensus, pCons) results in protection from full-blown disease attributable in part to the induction of CD4(+)CD25(+)Foxp3+ and CD8(+)Foxp3+ regulatory T cells. We compared 45 000 murine genes in total white blood cells (WBC), CD4(+) T cells, and CD8(+) T cells from splenocytes of (NZBxNZW) F1 lupus-prone mice tolerized with pCons vs untreated naïve mice and found two-fold or greater differential expression for 448 WBC, 174 CD4, and 60 CD8 genes. We identified differentially expressed genes that played roles in the immune response and apoptosis. Using real-time PCR, we validated differential expression of selected genes (IFI202B, Bcl2, Foxp3, Trp-53, CCR7 and IFNar1) in the CD8(+)T cell microarray and determined expression of selected highly upregulated genes in different immune cell subsets. We also determined Smads expression in different immune cell subsets, including CD4(+) T cells and CD8(+) T cells, to detect the effects of TGF-beta, known to be the major cytokine that accounts for the suppressive capacity of CD8(+) Treg in this system. Silencing of anti-apoptotic gene Bcl2 or interferon genes (IFI202b and IFNar1 in combination) in CD8(+) T cells from tolerized mice did not affect the expression of the other selected genes. However, silencing of Foxp3 reduced expression of Foxp3, Ifi202b and PD1-all of which are involved in the suppressive capacity of CD8(+) Treg in this model.

Bortezomib in patients with relapsed or refractory mantle cell lymphoma: updated time-to-event analyses of the multicenter phase 2 PINNACLE study.

BACKGROUND: We previously reported results of the phase 2, multicenter PINNACLE study, which confirmed the substantial single-agent activity of bortezomib in patients with relapsed or refractory mantle cell lymphoma (MCL). MATERIALS AND METHODS: We report updated time-to-event data, in all patients and by response to treatment, after extended follow-up (median 26.4 months). RESULTS: Median time to progression (TTP) was 6.7 months. Median time to next therapy (TTNT) was 7.4 months. Median overall survival (OS) was 23.5 months. In responding patients, median TTP was 12.4 months, median duration of response (DOR) was 9.2 months, median TTNT was 14.3 months, and median OS was 35.4 months. Patients achieving complete response had heterogeneous disease characteristics; among these patients, median TTP and DOR were not reached, and median OS was 36.0 months. One-year survival rate was 69% overall and 91% in responding patients. Median OS from diagnosis was 61.1 months, after median follow-up of 63.7 months. Activity was seen in patients with refractory disease and patients relapsing following high-intensity treatment. Toxicity was generally manageable. CONCLUSIONS: Single-agent bortezomib is associated with lengthy responses and notable survival in patients with relapsed or refractory MCL, with considerable TTP and TTNT in responding patients, suggesting substantial clinical benefit.

Subtyping psychological distress in the population: a semi-parametric network approach.

AIMS: The mechanisms underlying both depressive and anxiety disorders remain poorly understood. One of the reasons for this is the lack of a valid, evidence-based system to classify persons into specific subtypes based on their depressive and/or anxiety symptomatology. In order to do this without a priori assumptions, non-parametric statistical methods seem the optimal choice. Moreover, to define subtypes according to their symptom profiles and inter-relations between symptoms, network models may be very useful. This study aimed to evaluate the potential usefulness of this approach. METHODS: A large community sample from the Canadian general population (N = 254 443) was divided into data-driven clusters using non-parametric k-means clustering. Participants were clustered according to their (co)variation around the grand mean on each item of the Kessler Psychological Distress Scale (K10). Next, to evaluate cluster differences, semi-parametric network models were fitted in each cluster and node centrality indices and network density measures were compared. RESULTS: A five-cluster model was obtained from the cluster analyses. Network density varied across clusters, and was highest for the cluster of people with the lowest K10 severity ratings. In three cluster networks, depressive symptoms (e.g. feeling depressed, restless, hopeless) had the highest centrality. In the remaining two clusters, symptom networks were characterised by a higher prominence of somatic symptoms (e.g. restlessness, nervousness). CONCLUSION: Finding data-driven subtypes based on psychological distress using non-parametric methods can be a fruitful approach, yielding clusters of persons that differ in illness severity as well as in the structure and strengths of inter-symptom relationships.

Effects of dietary wheat bran on absorption and accumulation of PCBs in rats.

Polychlorinated biphenyls (PCBs) are toxic environmental contaminants, which tend to accumulate in the food chain. Since dietary intake is the most important exposure route, PCB body burden may be affected by taking proper dietary measures. In the present study, diets were supplemented with either wheat bran or its cellulose based placebo in order to study the effect of bran consumption on the absorption of dietary PCBs and the excretion of initially stored PCBs. During the period of PCB intake, faecal PCB excretion was elevated by consumption of wheat bran as compared to the placebo. Hence, apparent faecal PCB digestibilities as well as PCB retentions in the whole body were lower in the wheat bran consuming rats. After ending PCB consumption, dietary wheat bran had only a minor effect on faecal PCB output while accumulation in the body was not affected. When PCBs were consumed for a longer time, a small but significant reduction of apparent faecal PCB digestibility was found. However, PCB content in the body kept increasing while PCB retention as percent of intake remained almost constant. Furthermore, differences among individual PCB congeners in metabolic susceptibility and hydrophobic characteristics had an impact on their accumulation in the body.

20-epi-vitamin D3 analogues: a novel class of potent inhibitors of proliferation and inducers of differentiation of human breast cancer cell lines.

We have studied the in vitro biological activities and mechanism of action of 1,25-dihydroxyvitamin D3 (1,25D3) and four potent 1,25D3 analogues [20-epi-22oxa-24a,26a,27a-tri-homo-1,25(OH)2D3 (KH 1060); 20-epi-1,25(OH)2D3; 1,25(OH)2-16ene-D3; and 1,25(OH)2-16ene-23yne-D3] on proliferation and differentiation of estrogen receptor-negative (MDA-MB-436, BT-20, SK-BR-3, and MDA-MB-231), estrogen receptor-weakly positive (BT474), and estrogen receptor-positive (MCF-7) breast cancer cell lines. Dose-response studies showed that KH 1060 was the most potent analogue, because it was able to induce differentiation in all seven breast cancer cell lines (measured by lipid staining) and to suppress more than 50% clonal proliferation (ED50) at 10(-10) M in all cell lines, except MDA-MB-436 and BT-20. To explore how these compounds mediated antiproliferative actions, their effects on the cell cycle, on expression of bcl-2 and p53, and on apoptosis were assessed. Five of six cell lines have a mutant p53 gene, whereas MCF-7 has wild-type p53. Immunohistochemical staining showed that the p53 protein was predominantly localized in the nucleus in each of the breast cancer cell lines except for MCF-7, which expressed the protein predominantly in the cytoplasm. After incubation with KH 1060 (3 days; 10(-7) M), expression of bcl-2 protein as determined by immunohistochemical localization was markedly decreased in BT-474, MCF-7, and MDA-MB-231; these same cells were profoundly inhibited in their clonal proliferation and arrested in the G0/G1 phase of the cell cycle when cultured with KH 1060. In contrast, BT-20 and MDA-MB-436 cells that were refractory to the antiproliferative effect of KH 1060 (ED50 < 10(-6) M) had no down-regulation of their bcl-2 expression and no cell cycle changes after exposure to KH 1060. MCF-7 showed morphological changes and DNA fragmentation, indicative of apoptosis after 48 h incubation with KH 1060 (10(-6) M), during which time p53 protein accumulated in the nucleus and decreased in the cytoplasm. In contrast, no apoptosis was detected in three other breast lines (MDA-MB-231, SK-BR-3, and BT-474) that had a mutated p53. In conclusion, the data indicate that KH 1060 is an extremely potent 1,25D3 analogue inducing differentiation of all six breast cancer lines and potently inhibiting clonal growth of four of them with concomitant decreased bcl-2 and cell cycle arrest at G0/G1.(ABSTRACT TRUNCATED AT 400 WORDS)

Transforming growth factor-beta 1 interferes with the proliferation-inducing activity of stem cell factor in myelogenous leukemia blasts through functional down-regulation of the c-kit proto-oncogene product.

Blast cells, obtained from patients with acute myelogenous leukemia (AML), that express surface binding sites for human stem cell factor (SCF) respond proliferatively upon exposure to this molecule. In the presence of human transforming growth factor-beta 1 (TGF-beta 1) the capacity of SCF to augment the proliferative state of AML blasts was, however, almost completely abolished. This inhibitory action of TGF-beta 1 could be reversed by a neutralizing anti-TGF-beta 1 antibody. Studies on the mechanism of TGF-beta 1 inhibition of SCF-induced proliferation of AML blasts revealed that TGF-beta 1 treatment of these cells was associated with down-regulation of SCF receptor surface expression, as detected with a specific monoclonal antibody, which appeared to be preferentially due to an acceleration of decay of mRNA for the c-kit proto-oncogene encoding the SCF receptor, without an effect on the overall transcriptional activity of the c-kit gene. Direct evidence to prove the importance of c-kit down-regulation in the inhibitory effect of TGF-beta 1 on AML growth came also from experiments demonstrating that signal transduction of SCF could be significantly diminished in the presence of TGF-beta 1, as demonstrated by measuring c-kit kinase-associated phosphorylation of target proteins.

Synergy of interleukin 3 and tumor necrosis factor alpha in stimulating clonal growth of acute myelogenous leukemia blasts is the result of induction of secondary hematopoietic cytokines by tumor necrosis factor alpha.

Colony growth of leukemic colony-forming units (L-CFU) obtained from patients with primary acute myelogenous leukemia stimulated with recombinant human interleukin 3 (rh IL-3) is significantly potentiated when recombinant human tumor necrosis factor alpha (rh TNF-alpha) is present in cultures. The costimulatory activity of tumor necrosis factor (TNF) alpha is dose dependent and maximum at TNF-alpha concentrations of 10 ng/ml. At high density, L-CFU proliferatively respond to TNF-alpha stimulation in the absence of exogenous rh IL-3. Studies of the mechanism of action of rh TNF-alpha on acute myelogenous leukemia L-CFU growth suggest that TNF-alpha acts by inducing release of growth stimulatory hematopoietic cytokines by the leukemic cells themselves, including IL-1 alpha, IL-1 beta, Granulocyte-macrophage colony-stimulating factor (CSF), granulocyte CSF, and IL-6. Treatment of L-CFU cultures, with neutralizing antibodies to IL-1 alpha, IL-1 beta, granulocyte-macrophage CSF, granulocyte CSF, and IL-6 to eliminate the endogenous source of these factors is associated with significant inhibition of the synergistic interplay of TNF-alpha and IL-3.

Recombinant human stem cell factor stimulates growth of a human glioblastoma cell line expressing c-kit protooncogene.

The growth of a panel of eight different human glioblastoma cell lines was examined in a human tumor cloning assay in agar, a tritiated thymidine uptake assay, and by counting cell numbers, in cultures performed in the absence or presence of increasing concentrations (1 to 100 ng/ml) of recombinant human stem cell factor (SCF). Growth of 7 of 8 cell lines was not significantly and reproducibly affected by recombinant human SCF. However, growth of the CRL 1620 cell line could be stimulated up to 5-fold by the cytokine. In contrast to the other cell lines investigated, CRL 1620 expressed the c-kit protooncogene assessed on the mRNA and protein level. Furthermore, SCF-induced proliferation of CRL 1620 cells was sensitive to the tyrosine kinase inhibitor erbstatin. Our data suggest that SCF can be operative in growth modulation of malignant cells outside the hematopoietic system, and this finding should be further studied for its possible clinical implications.

Dissecting histidine interactions of ribonuclease T1 with asparagine and glutamine replacements: analysis of double mutant cycles at one position.

His92 of Ribonuclease T1 combines functional and structural features involving both imidazole nitrogens. To evaluate the use of Asn and Gln substitutions in dissecting the properties of histidines, we analysed the consequences of the His92Gln and His92Asn substitutions on the enzyme's structure, function, and conformational stability by protein engineering and X-ray crystallographic methods. In the X-ray structures of wild-type and His92Gln RNase T1 in complex with 2'-GMP the His92-N epsilon 2 and Gln92-N epsilon 2 atoms are isosterically equivalent. Similarly, the His92N delta 1H...OAsn99 hydrogen bond observed in wild-type is replaced by an equivalent Asn92N delta 2H...OAsn99 in the His92Asn mutant structure. Double mutant cycles at a single position were used to analyse the intermolecular and intramolecular interactions of the exchangeable proton and the individual histidine nitrogens. Urea denaturation measurements as a function of pH revealed that the exchangeable proton of His92, rather than its imidazole ring is contributing about 1 kcal/mol to the conformational stability of RNase T1. The stabilizing and the destabilizing effects of the (His-->Gln) and the (His-->Asn) mutations on urea denaturation of RNase T1 at pH 9.0 suggest that the unprotonated N delta 1 and N epsilon 2 atoms contribute in a compensating way to the conformational stability of RNase T1. A comparative study of the kinetics of all mutants suggests that the protonated His92 imidazole is a strictly co-operative catalytic device.

Immunotherapy against murine leukemia.

The central hypothesis underlying specific anti-leukemia immunotherapy is that leukemic cells express antigenic determinants not expressed on their counterpart normal adult cells. We have developed a murine myeloid leukemia/tumor immunization model using the low-immunogenic WEHI3 leukemia in syngeneic mice. Mice preimmunized with irradiated, transduced IL-7-producing WEHI3 cells showed systemic protection and rejection of a lethal dose of intravenously (i.v.) injected parental WEHI3 cells (5 x 10(4)) with 40% long-term survival. When vaccinated with a mixture of parental WEHI3 cells and IL-2-producing NIH-3T3 fibroblasts (5 x 10(5)), 60% survival was observed. Vaccination with murine granulocyte-macrophage colony-stimulating factor (GM-CSF)-producing WEHI3 cells resulted in only 20% survival of i.v. challenged mice, and the additional combination of IL-2- and IL-7-producing vaccine did not reveal any additive or synergistic effects. Immunizing mice with a pre-established leukemia burden (injected with 5 x 10(4) WEHI3 cells, i.v., 3 days prior to immunization) did not cure or result in a prolongation of survival, indicating that improved methods of immunization are needed. Taken together, we have identified IL-7 and IL-2 as effective cytokines in our leukemia/vaccination model with only marginal activity by GM-CSF.

Polychlorinated biphenyl distribution and faecal excretion in rats fed wheat bran.

Polychlorinated biphenyls (PCBs) are abundant and persistent environmental contaminants, which tend to accumulate through the food chain. Because of the toxic potential of these compounds, body burden should be kept as low as possible e.g. by taking dietary measures. In the present report, the effect of wheat bran consumption on absorption of dietary PCBs as well as on excretion of previously absorbed PCBs was investigated in rats. Moreover, the accumulation of 7 reference PCB congeners in liver and abdominal adipose tissue was studied. Faecal excretion of dietary PCBs was significantly higher in rats fed wheat bran compared to its placebo. As a result, apparent PCB digestibility was diminished, but not enough to significantly affect PCB accumulation in liver and abdominal adipose tissue. Furthermore, excretion of previously absorbed PCBs following switching of the rats to a control diet without added PCBs was enhanced by wheat bran fibre intake, although to a much lesser extent than excretion of PCBs originating directly from the diet. Consequently, stimulation of PCB clearance from liver and abdominal adipose tissue due to wheat bran consumption was not detectable. Although no preferential absorption of PCB congeners was observed, PCB patterns in tissues obviously differed from the dietary PCB pattern. This was mainly due to PCBs 52 and 101, which were metabolised in the body. Moreover, reduced levels of PCB 138 were found in liver, while PCB 28 and 138 were predominantly present in adipose tissue. The experiment also demonstrated that PCB redistribution from the liver to the adipose tissue occurs.

Digestibility, retention and incorporation of low-level dietary PCB contents in laying hens.

Polychlorinated biphenyls (PCBs) are persistent and hazardous environmental contaminants, which tend to bioaccumulate in the food chain. In the present report the long-term effect of low-level dietary PCB concentrations was studied on performance, egg quality, apparent PCB digestibility, apparent PCB retention and PCB accumulation in laying hens that were fed experimental diets for 41 weeks. The tested dietary concentrations of supplemented PCBs, based on the sum of seven reference congeners, were 0, 1.5 and 6 ng/g. PCB ingestion did not significantly affect performance or egg quality parameters. The PCB concentration in egg yolk reached a nearly constant level after approximately 40 and 70 days of consumption of the diets containing 1.5 and 6 ng PCBs/g, respectively. Apparent faecal PCB digestibility and apparent retention were not influenced by dietary levels of added fat varying between 1.5% and 4.5%, but were significantly higher in hens fed diets containing added PCBs. Moreover, apparent PCB digestibility and retention increased significantly with age. Among the seven individual PCB congeners, no systematically significant differences with regard to apparent faecal digestibility were observed throughout the experiment. Accumulation of PCBs in the fat fraction of egg yolk, abdominal adipose tissue and thigh and breast muscle greatly depended upon PCB intake, but never exceeded the maximally allowed concentration of 200 ng/g. As PCBs 52 and 101 were hardly found in egg yolks and hen tissues, it was concluded that both congeners were greatly metabolised. Comparison of relative contents of individual PCB congeners revealed that PCBs 118, 138 and 153 were preferentially incorporated in yolk and body tissues.

Inhibition of in vitro hematopoiesis by hepatitis A virus.

Inoculation of human bone marrow with hepatitis A virus (HAV) resulted in a dose- and duration-of-incubation-dependent suppression of hematopoietic progenitor (CFU-GM, BFU-E, CFU-Mix) growth in vitro. Monocytic progenitors appeared to be least affected. While HAV inactivation by heat or beta-propiolactone and neutralization by specific antibodies completely abrogated hematopoietic inhibition, depletion of adherent bone marrow cells, and enrichment of progenitors did not alter the pattern of suppression, which also seemed to be independent of HuIFN-alpha, -beta, -gamma, and TNF. These findings support the concept that direct infection of progenitor cells by HAV may be responsible for hematologic changes commonly seen during early phases of infectious hepatitis and possibly for some cases of bone marrow failure.

Kaposi's sarcoma-associated herpesvirus/human herpesvirus type 8 encephalitis in HIV-positive and -negative individuals.

OBJECTIVE: Kaposi's sarcoma-associated herpesvirus (KSHV) human herpesvirus type 8 (HHV-8) has been associated with Kaposi's sarcoma and a variety of benign lymphoid proliferations including angioimmunoblastic lymphadenitis with dysproteinemia and Castleman's disease. KSHV/HHV-8 has also been associated with inflammatory conditions including interstitial pneumonitis. Although herpesviruses are commonly associated with encephalitis in immunosuppressed individuals, KSHV/HHV-8 has not previously been associated with central nervous system disease other than lymphoma. The first cases of KSHV/HHV-8 associated encephalitis have been described. METHODS AND DESIGN: KSVH/HHV-8 sequences were evaluated in brain biopsies from three cases of otherwise unexplained encephalitis from three patients, two of whom were positive for HIV. Amplification of the polymerase chain reaction product was confirmed with Southern blot hybridization on three separate occasions, and with appropriate positive and negative controls. RESULTS: All three cases of encephalitis were associated with KSHV/HHV-8 sequences. Characteristic lesions included endothelial cell swelling and perivascular cuffing by lymphocytes. CONCLUSIONS: KSHV/HHV-8 was associated with encephalitis in immunosuppressed individuals, and should have been considered in the differential diagnosis of unexplained viral encephalitis. KSHV/HHV-8 may have tropism for the central nervous system.

Post-transcriptional regulation of interleukin-6 gene expression in human keratinocytes by ultraviolet B radiation.

Exposure to increasing doses (290-315 nm) of ultraviolet (UV) B radiation is thought to profoundly affect human health. Studies on the biologic and molecular effects of UVB radiation on human skin are therefore of particular interest. There is experimental and clinical evidence to assume that UVB radiation-induced local and systemic inflammatory reactions might be mediated at least in part by UVB-induced keratinocyte-derived interleukin (IL)-6. Previously, a UVB-induced increase of steady-state levels of IL-6 mRNA was found to be a prerequisite for keratinocyte IL-6 production after UVB irradiation. The present study was aimed at addressing the question of whether in vitro UVB irradiation would increase IL-6 mRNA expression in long-term cultured, normal human keratinocytes via transcriptional or post-transcriptional mechanisms. UVB exposure (0-100 J/m2) of keratinocytes increased low baseline expression levels of IL-6 mRNA in a time- and dose-dependent manner. Using nuclear run-on assays, transcription rates of the IL-6 gene in nuclei isolated from UVB-irradiated cells were found to be essentially identical to those seen in unirradiated cells, indicating that UVB light did not lead to increased transcription of the IL-6 gene. To determine a possible post-transcriptional mechanism in UVB-induced IL-6 mRNA expression, the effects of UVB irradiation on IL-6 mRNA stability were examined. To this end irradiated and unirradiated keratinocytes were treated with actinomycin D and subjected to Northern blot analysis to calculate IL-6 mRNA half-life. As compared with unirradiated cells, IL-6 mRNA stability was increased significantly (three- to four-fold) in UVB-irradiated cells, suggesting that UVB radiation upregulates IL-6 mRNA levels in human keratinocytes by increasing the stability of IL-6 transcripts. This is the first report indicating that UVB radiation at a physiologically relevant dose may affect gene expression in human cells at a post-transcriptional level.

Kaposi's sarcoma-associated herpesvirus and human herpesvirus 8 (KSHV/HHV8)-associated lymphoma of the bowel. Report of two cases in HIV-positive men with secondary effusion lymphomas.

This report describes two cases of Kaposi's sarcoma-associated herpesvirus/human herpesvirus-8 (KSHV/HHV8)-associated lymphomas that primarily involved the large bowel and that secondarily caused malignant effusions. Involvement of the gastrointestinal tract is of interest because epidemiologic evidence suggests that KSHV/HHV-8 may be transmitted via the fecal-oral route, and KSHV/HHV8 DNA has been detected in rectal samples from HIV-positive patients. This report describes two HIV-positive men who developed primary KSHV/ HHV8-associated lymphomas of the bowel. Despite similar morphology and immunophenotype, these cases differ from most KSHV/HHV8-associated primary effusion lymphomas, which present with malignant effusions in the absence of a solid tumor mass. The spectrum of KSHV/HHV8-associated lymphomas is expanded to include a subset of primary bowel lymphomas in individuals infected with human immunodeficiency virus.

Vitamin D3 analogs: effect on leukemic clonal growth and differentiation, and on serum calcium levels.

In vitro, 1,25-dihydroxyvitamin D3 (1,25(OH)2D3) induces differentiation of HL-60 cells and inhibits their proliferation as well as the proliferation of leukemic cells from patients. In vivo, the survival of mice challenged with syngeneic leukemic cells is enhanced by treatment with 1,25(OH)2D3. Patients treated with 1,25(OH)2D3 develop hypercalcemia at a serum level of 2 x 10(-10) mol/l which is a concentration too low to achieve an antileukemic effect in vitro. Several interesting vitamin D3 analogs have recently been developed. We initially examined the effect of 1,25(OH)2-16ene-23yne-19-nor-26,27-F6-D3 and 24a,26a,27a-tri-homo-22,24-diene-1-alpha,25-(OH)2-D3 on clonal growth and differentiation of HL-60 cells. Each of the analogs had comparable effects on clonal growth with 50% inhibition (ED50) at concentrations of 0.2-0.5 x 10(-9) M; 1,25(OH)2D3 was about 20- to 50-fold less active in inhibiting growth. Differentiation was determined by induction of superoxide production, as measured by nitroblue tetrazolium (NBT) reduction and by expression of a macrophage-specific enzyme (alpha napthyl acetate esterase (ANAE)). The 24a,26a,27a-tri-homo-22,24-diene-1-alpha,25-(OH)2-D3 and 1,25(OH)2-16ene-23yne-19-nor-26,27-F6-D3 were about 5- to 14-fold more potent than 1,25(OH)2D3. The hypercalcemia inducing side-effects of these analogs and three other previously identified, extremely potent vitamin D3 compounds, as well as 1,25(OH)2D3, were studied. The analogs were administered intraperitoneally every other day (qod) for 5 weeks; serum was collected weekly and Ca2+ measured by atomic absorption spectrophotometry. The highest tolerated dose of each analog leaving all mice alive was for 1,25(OH)2D3: 0.25 micrograms; 1,25(OH)2-24a,26a,27a-tri-homo-22,24-diene-D3: 0.25 micrograms; and 1,25(OH)2-16ene-23yne-19-nor-26,27-F6-D3: 0.0625 micrograms. Another hexafluoro compound with potent abilities to induce differentiation (1,25(OH)2-16ene-23yne-26,27-F6-D3) was very toxic, all mice died in the second week while receiving 0.0625 micrograms qod. Prior studies showed that the most potent compound in inducing differentiation of HL-60 was 1,25(OH)2-20-epi-D3; but it is very toxic as only one mouse survived a dose of > or = 0.0125 micrograms qod for 5 weeks. 1,25(OH)2-16ene-23yne-D3 is an extremely active inducer of differentiation but, on the other hand, it has low potential to produce hypercalcemia; mice maintained normal serum calcium levels even while receiving 2 micrograms qod for 5 weeks.(ABSTRACT TRUNCATED AT 400 WORDS)