Serum ICAM-1 concentrations following conventional dose consolidation chemotherapy for acute myeloid leukemia and after high dose chemotherapy with autologous haematopoietic stem cell rescue.

Serum concentrations of soluble ICAM-1 (sICAM-1) were studied in patients with acute myeloid leukemia (AML) after conventional dose consolidation chemotherapy and in AML and in breast cancer patients following high dose chemotherapy with autologous haematopoietic stem cell transplantation. Investigations were carried out at 3 phases following treatment; during the chemotherapy induced neutropenic phase (neutrophil counts <0.5x109/l); during early recovery (neutrophil counts 0.5x109/l-1.0x109/l); and at recovery from neutropenia (neutrophil count 1.0x109/l-2.5x109/l). Results showed a significant elevation of serum levels of sICAM-1, above normal, in both groups of patients during the neutropenic phase. A further increase of sICAM-1 was found in conventional dose consolidation chemotherapy treated AML patients during the post-neutropenia recovery phases. By contrast, patients who were treated with high dose chemotherapy plus autologous haematopoietic stem cell transplantation showed a normalisation of sICAM-1 concentration during the post-neutropenic recovery phases. These findings suggest that recovery of neutrophil function do not coincide with recovery of neutrophil count following intensive chemotherapy while rapid recovery of neutrophil function occurred among patients who received autologous haematopoietic stem cell support.

Expression of CD11b/CD18 on neutrophils after consolidation chemotherapy for acute myeloid leukemia and after high dose chemotherapy with autologous haematopoietic stem cell transplantation.

Quantitative expression of neutrophil CD11b/CD18 following chemotherapy (either conventional dose consolidation chemotherapy or high dose chemotherapy with autologous stem cell transplantation) was investigated during the early recovery phase (neutrophil count 0. 5-1.0x109/l) and at full recovery (neutrophil count 1.0-2.5x109/l) following treatment. CD11b/18 expression was normal in stem cell transplantation supported patients during both early and full neutrophil recovery. By contrast CD11b/CD18 expression was markedly decreased in patients who received chemotherapy without stem cell support. These results suggest that recovery of neutrophil count may not always coincide with recovery of neutrophil function and that G-CSF stimulated peripheral stem cell transplantation enhances neutrophil function post chemotherapy.

Alkylator resistance in human B lymphoid cell lines: (2). Increased levels of topoisomerase II expression and function in a melphalan-resistant B-CLL cell line.

Previous studies have demonstrated alkylating (melphalan) resistance in the B-CLL derived WSU-CLL cell line as compared to WIL2 B lymphocytic cells. Nuclear extracts from WSU-CLL cells demonstrate a highly significant increase in DNA topoisomerase II activity as compared to WIL2 cells. Western blot analysis showed the level of topoisomerase II proteins expressed in WSU-CLL cells to be increased as compared to WIL2 cells. WSU-CLL cells were 5.24-fold more sensitive than WIL2 cells to the cytotoxic effect of the topoisomerase II inhibitor doxorubicin. No difference in topoisomerase I activity or of the level of topoisomerase I protein expression was observed comparing the two cell lines. The sensitivity to the cytotoxic effects of topoisomerase I inhibitor, camptothecin, did not differ in WSU-CLL and WIL2 cell lines. Pre-incubation with doxorubicin significantly increased melphalan induced interstrand-DNA-crosslink formation and cytotoxicity in WSU-CLL cells as compared to WIL2 cells. The affinity of topoisomerase II for WSU-CLL UV-irradiated-crosslinked DNA was increased 2.84-fold as compared to that of WSU-CLL native DNA. The affinity of topoisomerase II for both UV-irradiated (crosslinked) and for native DNA was significantly decreased after doxorubicin-pretreatment. Measurement of DNA polymerase beta and DNA polymerase beta revealed significant elevations in DNA polymerase beta (58.82 +/- 3.67 units/mg protein in WSU-CLL cells, as compared to 27.82 +/- 4.39 units/mg protein in WIL 2 cells; p < 0.01) but not DNA polymerase beta (0.82 +/- 0.11 units/mg protein in WSU-CLL cells, compared to 0.74 +/- 0.09 units/mg protein in WIL2, p > 0.05). However, exposure to aphidicolin (an inhibitor of DNA polymerase a) failed to increase melphalan induced cytotoxicity suggesting that although DNA polymerase a activity was increased in WSU-CLL cells the mechanisms of resistance does not involve this specific DNA repair pathway. Elevated topoisomerase II activity and the increased affinity of topoisomerase II for crosslinked DNA in melphalan resistant cells appears to be the major factor responsible for alkylator resistance by changing DNA topology and thereby facilitating DNA repair.

The influence of different movements on ambulatory blood pressure in hypertensive subacute stroke patients.

OBJECTIVE: This study evaluated variation in blood pressure (BP) in hypertensive subacute stroke patients performing eight different types of active movement, and variations in BP over time. METHODS: The study included 35 subacute stroke patients (60 - 74 years old) and 15 age-matched healthy volunteers. Ambulatory systolic and diastolic BP was measured over 4 consecutive days, before and during active movement. RESULTS: The greatest effect of the different active movements in stroke patients was on mean systolic BP variability (BPV). There was a significant difference in systolic and diastolic BPV between stroke patients at different time-points and compared with healthy volunteers. Systolic BPV during shifting from the ward to the rehabilitation centre was significantly higher than for all other active movements. Mean systolic BPVs during the sessions on the first and second days were significantly higher than for the sessions on the third and fourth days in stroke patients and compared with healthy volunteers. CONCLUSIONS: Systolic BP was found to be increased in hypertensive subacute stroke patients during their first and/or second attempts at performing active movements. Therapists should consider the BP of hypertensive subacute stroke patients during these first two attempts, especially for activities involving the patient moving from the ward to the rehabilitation centre.

Interleukin-4 prevents spontaneous in-vitro apoptosis in chronic lymphatic leukaemia but sensitizes B-CLL cells to melphalan cytotoxicity.

The effect of IL4 on cell viability, cell growth, apoptotic fraction, melphalan-induced cytotoxicity and the degree of interstrand DNA cross-linking after alkylating agent exposure was investigated in peripheral blood B-cell chronic lymphocytic leukaemia (B-CLL) cells obtained from 10 patients suffering from chronic lymphocytic leukaemia and in B lymphocytes from five normal individuals. The addition of IL4 to culture medium maintained in-vitro viability and decreased spontaneous in-vitro apoptosis in both B-CLL cells and normal peripheral blood B lymphocytes. IL4 did not, however, stimulate proliferation of either cell type. IL4 sensitized alkylator-resistant B-CLL cells to the cytotoxic effects of melphalan (L-phenylalanine mustard) but had no influence on melphalan-induced cytotoxicity against normal B lymphocytes. The enhanced cytotoxicity against B-CLL cells was accompanied by an increase in the amount of interstrand-DNA cross-linking in these cells following short-term exposure to melphalan.

Induction of alkylator (melphalan) resistance in HL60 cells is accompanied by increased levels of topoisomerase II expression and function.

Human leukemic HL60 cells were selected for resistance to alkylating agents by stepwise exposure to increasing concentrations of L-phenylalanine mustard (melphalan). The resulting resistant cell line (R-HL60) was 4-fold resistant (melphalan IC50 value, 27.84 +/- 4.2 microM) to melphalan compared with parental HL60 cells (melphalan IC50 value, 6.9 +/- 1.78 microM). Nuclear extracts from R-HL60 cells possess a approximately 4-fold increase in DNA topoisomerase II activity compared with parental HL60 cells. As determined using Western blot analysis, the level of topoisomerase IIalpha protein expressed in R-HL60 cells was approximately 3-fold that of parental HL60 cells. However, there were no differences observed in the level of topoisomerase IIbeta protein, in the topoisomerase I activity, or in the level of topoisomerase I protein expression comparing the two cell lines. R-HL60 cells were 5-fold more sensitive than parental HL60 cells to the cytotoxic effect of the topoisomerase II inhibitor doxorubicin. The sensitivity to the cytotoxic effects of the topoisomerase I inhibitor camptothecin did not differ in R-HL60 and parental HL60 cell lines. Preincubation with doxorubicin significantly increased melphalan-induced interstrand DNA cross-link formation and cytotoxicity in R-HL60 cells compared with the parental HL60 cells. The affinity of topoisomerase II for UV-irradiated cross-linked HL60 DNA was increased by approximately 2.5-fold compared with that of HL60 native DNA. The affinity of topoisomerase II for both UV-irradiated (cross-linked) and native DNA was significantly decreased after doxorubicin pretreatment. Elevated topoisomerase II activity and the increased affinity of topoisomerase II for cross-linked DNA in melphalan-resistant cells seems to contribute to alkylator resistance by changing DNA topology, thereby facilitating DNA repair.