Increased growth inhibition of human chronic myelogenous leukemic cells by a combination of c-myb antisense oligonucleotide and 4-hydroxyperoxycyclophosphamide in vitro

Human chronic myelogenous leukemia (CML) is a unique malignancy in its cellular and molecular phenotypes. High dose therapy followed by stem cell transplantation seems to be one of the most effective treatment modalities for CML. However, allogeneic stem cell transplantation, a curative treatment modality, is limited due to the availability of matched siblings. On the other hand, the autologous stem cell harvests are contaminated with leukemic cells, and therefore a significant reduction of leukemic cells is desired before using the harvest for transplantation. Therefore in the present study, effects of a combination of a suboptimal concentration of 4-hydroxyperoxycyclophosphamide (4HC) and an optimal concentration of c-myb antisense oligonucleotide on the growth of K562 human chronic myelogenous leukemic cells in vitro were determined. The combination significantly (p<0.05) inhibited the growth of K562 cells in vitro when compared to the effects of c-myb oligonucleotide or 4HC alone. The c-myb oligonucleotide alone or in combination with low dose 4HC decreased the expression of c-myb gene as determined by RT-PCR techniques. Cellular uptake and retention of fluoresceinated oligonucleotide in control and treated K562 cells was studied using plain field laser microscopy and flow cytometry. There was an increase in cellular uptake of c-myb oligonucleotide in K562 cells as measured by plain field laser microscopy in the presence of 4HC. The combination of oligonucleotides and 4HC did not significantly decrease the number of hematopoietic stem/progenitor cells from normal hematopoietic stem cell harvests as determined by in vitro colony assays. The combination of low dose 4HC and c-myb antisense oligonucleotides can potentially be applied in CML patients, particularly for purging leukemic cells present in their hematopoietic stem cell harvests.

Oligonucleotides complementary to c-myb messenger RNA inhibit growth and induce apoptosis in human Burkitt lymphoma cells

A 24-mer (antisense) phosphorothioate oligonucleotide (ODN) corresponding to the codons 2-9 of the c-myb gene was evaluated for its effects on the growth of a human Burkitt lymphoma cell line (Raji) in vitro. Raji cells incubated with different concentrations of c-myb antisense ODN (5-15 mu g/ml) for 24-72 h showed a significant dose-dependent decrease in growth. The same concentrations of control (sense) or scrambled c-myb phosphorothioate ODNs did not inhibit Raji cell growth. The c-myb antisense ODN, but not the control ODNs, significantly decreased c-myb mRNA levels in treated cells as determined by RT-PCR. Additionally, the c-myb antisense ODN induced apoptosis of Raji cells as demonstrated by i) flow cytometry to enumerate the A(o) (apoptotic cell population) population of propidium iodide stained cells; ii) electron microscopy to evaluate the cell morphology; and iii) DNA fragmentation pattern. Thus, an antisense c-myb ODN causes significant growth inhibition of Burkitt lymphoma cells, and one mechanism of growth inhibition is the induction of apoptosis of the lymphoma cells. In addition, antisense c-myb ODN did not reduce CFU-GM or BFU-e colony-forming ability of normal hematopoietic stem/progenitor cells. Because the inhibition is sequence-specific and Burkitt lymphoma cell selective, evaluation of the therapeutic effects of c-myb antisense ODN against Burkitt lymphoma is warranted.

EPOCH-F: A salvage regimen for multiple myeloma prior to reduced intensity allogenic hematopoietic stem cell transplantation

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Background: Variation in baseline host immune status contributes to inconsistent donor engraftment and may impede maximal graft-versus-myeloma effects after reduced intensity allogenic hematopoietic stem cell transplantation (RIHSCT) for advanced multiple myeloma (MM). As no specific salvage regimen has been designed for MM patients being considered for RIHSCT, we evaluated EPOCH-F a novel salvage regimen designed to provide disease control and immune depletion. Methods: EPOCH-F is an infusional chemotherapeutic regimen consisting of etoposide, vincristine and adriamycin, with prednisone, cyclophosphamide and fludarabine given in 21 day cycles prior to RIHSCT. Targeting a CD4+ T cell count, 22 pts were treated <5 cycles of EPOCH-F. Pts proceeded to RIHSCT after adequate lymphodepletion or if there was disease progression during EPOCH-F, regardless of CD4 count. Results: Median age was 53 years (range 36–65); median time from initial therapy to transplant was 12 months (range 2–168). Median number of prior therapies was 2 (range 1–8), 63% had chemotherapy sensitive disease and 68% had received a novel agent. Pts received a median of 3 cycles (range 1–5), with manageable toxicities, mostly hematologic. Grade IV Neutropenia was seen in 77% of the administered cycles with only 6 episodes of neutropenic fever. Median lymphocyte count decreased from 1423/μL (range 335–2788) to 519/μL (range 102–1420); CD4 count decreased from 320/μL (range 130–1366) to 115/μL (30–309). In 21 evaluable pts, the ≥PR rate to EPOCH-F was 22% with 13% CR/nCR. 68% had SD and only 1 pt progressed. 20 pts underwent RIHSCT from HLA matched sibling. Median Day 100 chimerism was 100% (range 60–100, mean 95). 70% of patients achieved ≥VGPR and CR/nCR was seen in 40%. Acute GVHD (grade II-IV) was seen in 47% and chronic GVHD (grade III-IV) was seen in 52% of the pts. TRM at 100 days was 5% and 30% at 60 months. Median overall survival of patients after RIHSCT was 46.1 months. Conclusions: EPOCH-F is an active regimen which provides pre-transplantation lympho-depletion, disease control and allows consistent engraftment in multiple myeloma patients undergoing RIHSCT.

No significant financial relationships to disclose.

Ureteric stents: investigating flow and encrustation

Blockages of the ureter, e.g. due to calculi (kidney stones), can result in an increase in renal pelvic pressure. This may be relieved by inserting a stent (essentially a permeable hollow tube). However, a number of complications are associated with stent use. Stents can result in reflux (backflow of urine along the ureter), which will promote recurrent urinary infection and possible renal parenchymal damage. Furthermore, long-term stent use is associated with infection and precipitation of salts from the urine, which can lead to a build-up of crystalline deposits on the stent surface, making stent removal difficult and painful. This paper examines factors governing urine flow in a stented ureter, the implications for reflux, and the processes by which the stent surface encrusts, in particular focusing on the influence of bacterial infection. An interdisciplinary approach is adopted, involving a combination of theoretical investigations and novel experiments.

Disease-associated prion protein is not detectable in human systemic amyloid deposits

Cerebral and cardiac amyloid deposits have been reported after scrapie infection in transgenic mice expressing variant prion protein (PrP(C)) lacking the glycophosphatidylinositol anchor. The amyloid fibril protein in the systemic amyloid deposits was not characterized, and there is no clinical or pathological association between prion diseases and systemic amyloidosis in humans. Nevertheless, in view of the potential clinical significance of these murine observations, we tested both human amyloidotic tissues and isolated amyloid fibrils for the presence of PrP(Sc), the prion protein conformation associated with transmissible spongiform encephalopathy (TSE). We also sequenced the complete prion protein gene, PRNP, in amyloidosis patients. No specific immunohistochemical staining for PrP(Sc) was obtained in the amyloidotic cardiac and other visceral tissues of patients with different types of systemic amyloidosis. No protease-resistant prion protein, PrP(res), was detectable by Western blotting of amyloid fibrils isolated from cardiac and other systemic amyloid deposits. Only the complete normal wild-type PRNP gene sequence was identified, including the usual distribution of codon 129 polymorphisms. These reassuringly negative results do not support the idea that there is any relationship of prions or TSE with human systemic amyloidosis, including cardiac amyloid deposition.

Correlations among vitality, physical competence, lipid profile and measures of inflammation in transplant survivors with chronic graft versus host disease

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Background: Chronic graft vs. host disease (cGVHD) is a multi-system disorder and a late complication of cancer therapy experienced by more than 50% of survivors after allogeneic hematopoietic stem cell transplantation. An improved understanding of the underlying biology and its relation to clinical symptoms may guide the development of better treatments for cGVHD. Methods: In a prospective, cross-sectional natural history protocol we examined the associations among organ/system dysfunction, measures of physical performance and health status with clinical measures of inflammation and fat metabolism. Variables included: 1. a composite severity score (CAS) rated by clinician-specialists (skin, eyes, mouth, gastrointestinal/liver, hematological, gynecological, pulmonary function evaluations); 2.functional measures [2 minute walk time (WT), grip strength (GS), SF-36 physical component summary score (PCS), vitality (VT) subscale, maximal activity score (MAS) of the Human Activity Profile]; 3.Laboratory tests (glucose, LDH, hemoglobin, ferritin, platelets, lymphocytes, pre-albumin, cholesterol, lipoproteins (HDL, LDL), triglycerides (TG), beta-2microglobulin (B2), and CRP. Results: 43 pts (mean age 47 yrs) with prior hematologic malignancy participated (mean 3 yrs post transplant). An average of 3.5 organ systems were affected, 77% were on systemic treatment for cGVHD, and 67% had prior acute GVHD. The mean body mass index (BMI) was 25, TG 255, cholesterol 222, LDL 132. They were moderately disabled by self-report (MAS), had slower than normal WT (540 ft/min), lower than normal GS (63 pounds), PCS (36) and VT (46) than a healthy population. Using a backward selection model with a significance of 0.1, low lung diffusing capacity (p<.001) and low PCS (p=0.01) correlated with high CAS. VT correlated negatively with LDH, platelets, B2 and LDL (all p<0.01). Low GS correlated with high LDH and B2 (p=0.01). Conclusions: Reported physical function and vitality in cGVHD patients are associated with abnormal lipid profiles and markers of inflammation. Establishment of such profiles is a critical step in the development of testable and validated outcome measures and for evaluation of new therapies in cGVHD.

No significant financial relationships to disclose.

Managing waiting time for radiotherapy: A single machine unit experience

Waiting time (WT) for radiotherapy (RT) is a significant clinical problem. This paper examines various strategies for managing WT for patients treated with radical and palliative intent in the new setting of a rural single machine unit in Australia. Cohorts of patients undergoing both radical and palliative RT in Bendigo had their WT prospectively recorded. Matched cohorts from the hub centre (Peter MacCallum Cancer Centre, Melbourne) treated with palliative intent were also collated. Strategies implemented included a devoted priority meeting, palliative points system, and reallocation of appointment times. The audit was to continue until best practice guidelines were bettered. Three cohorts of patients were compared. There is a significant trend for increasing numbers of patients treated per month since the centre opened (P < 0.0001). The ratio of palliative to radical intent patients remained stable between 46 and 52%. Mean WT for palliative RT reduced from 25 days in the first cohort to 7 days in the final cohort (P < 0.0005). Waiting time for palliative RT was initially longer at Bendigo than the hub centre (P < 0.0005), but by the final cohort there was a non-significant difference favouring the Bendigo cohort (P = 0.26). Waiting time for radical treatment also improved throughout the three cohorts in Bendigo (P < 0.0005). A number of new strategies have successfully resulted in the abolition of lengthy WT for RT in Bendigo despite the increasing demand for the RT service.

Ambrosius Holbein's memento mori map for Sir Thomas More's Utopia. The meanings of a masterpiece of early sixteenth century graphic art

This paper describes how, and asks why, the Renaissance artist Ambrosius Holbein hid a skull within the overall design of his woodcut map of Sir Thomas More's Utopia. (Fig. 2) This map was prepared for the 1518 Froben edition of the book, and was probably commissioned by Erasmus of Rotterdam. Its identification now is made easier by the habits of interpretation with which all dentists are equipped thanks to their skill in dental radiology, and by the recognition of teeth appearing in an unlikely disguise.