Biomedical subjects

M Vowels

Publications and source records attributed to M Vowels.

At least 19 recordsLinked to original sources

PubMed2006

Novel cryoprotectant significantly improves the post-thaw recovery and quality of HSC from CB.

BACKGROUND: Hematopoietic stem cells (HSC) have traditionally been frozen using the cryoprotectant DMSO in dextran-40, saline or albumin. However, the process of freezing and thawing results in loss of HSC numbers and/or function. METHODS: This study investigated the use of CryoStor for the freezing of HSC from cord blood (CB). CB donations (n = 30) were collected under an Institutional Ethics Committee-approved protocol, volume reduced and frozen using three different methods of cryoprotection. Aliquots were frozen with either 10% DMSO in dextran-40, 10% DMSO in CryoStor or 5% DMSO in CryoStor. Prior to freezing samples were separated for nucleated cell (NC) and CD34+ counts and assessment of CD34+ viability. Aliquots were frozen and kept in vapor phase nitrogen for a minimum of 72 h. Vials were rapidly thawed at 37 degrees C and tested for NC and CD34+ counts and CD34+ viability and colony-forming unit (CFU) assay. RESULTS: Cells frozen with CryoStor in 10% DMSO had significantly improved NC (P < 0.001), CD34+ recovery, viable CD34+ (P < 0.001) and CFU numbers (P < 0.001) compared with dextran in 10% DMSO. CryoStor in 5% DMSO resulted in significantly improved NC (P < 0.001) and CFU (P < 0.001). DISCUSSION: These results suggest that improved HSC recovery, viability and functionality can be obtained using CryoStor with 10% DMSO and that similar if not better numbers can be obtained with 5% DMSO compared with dextran-40 with 10% DMSO.

Antigens, CD34↗

PubMed2001

Comparison of outcomes of unrelated bone marrow and umbilical cord blood transplants in children with acute leukemia.

In order to compare the outcomes of unrelated umbilical cord blood transplants (UCBTs) or bone marrow transplants, 541 children with acute leukemia (AL) transplanted with umbilical cord blood (n = 99), T-cell-depleted unrelated bone marrow transplants (T-UBMT) (n = 180), or nonmanipulated (UBMT) (n = 262), were analyzed in a retrospective multicenter study. Comparisons were performed after adjustment for patient, disease, and transplant variables. The major difference between the 3 groups was the higher number in the UCBT group of HLA mismatches (defined by serology for class I and molecular typing for DRB1). The donor was HLA mismatched in 92% of UCBTs, in 18% of UBMTs, and in 43% of T-UBMTs (P <.001). Other significant differences were observed in pretransplant disease characteristics, preparative regimens, graft-versus-host disease (GVHD) prophylaxis, and number of cells infused. Nonadjusted estimates of 2-year survival and event-free survival rates were 49% and 43%, respectively, in the UBMT group, 41% and 37% in the T-UBMT group, and 35% and 31% in the UCBT group. After adjustment, differences in outcomes appeared in the first 100 days after the transplantation. Compared with UBMT recipients, UCBT recipients had delayed hematopoietic recovery (Hazard ratio [HR] = 0.37; 95% confidence interval [95CI]: 0.27-0.52; P <.001), increased 100 day transplant-related mortality (HR = 2.13; 95CI: 1.20-3.76; P <.01) and decreased acute graft-versus-host disease (aGVHD) (HR = 0.50; 95CI: 0.34-0.73; P <.001). T-UBMT recipients had decreased aGVHD (HR = 0.25; 95CI: 0.17-0.36; P <.0001) and increased risk of relapse (HR = 1.96; 95CI: 1.11-3.45; P =.02). After day 100 posttransplant, the 3 groups achieved similar results in terms of relapse. Chronic GVHD was decreased after T-UBMT (HR = 0.21; 95CI: 0.11-0.37; P <.0001) and UCBT (HR = 0.24; 95CI: 0.01-0.66; P =.002), and overall mortality was higher in T-UBMT recipients (HR = 1.39; 95CI: 0.97-1.99; P <.07). In conclusion, the use of UCBT, as a source of hematopoietic stem cells, is a reasonable option for children with AL lacking an acceptably matched unrelated marrow donor.

Analysis of Variance↗

PubMed2001

Impact of donor type on outcome of bone marrow transplantation for Wiskott-Aldrich syndrome: collaborative study of the International Bone Marrow Transplant Registry and the National Marrow Donor Program.

Human leukocyte antigen (HLA)-identical sibling bone marrow transplantation is an effective treatment for Wiskott-Aldrich syndrome. However, most children with this disease lack such donors and many patients receive transplants from alternative donors. This study compared outcomes of HLA-identical sibling, other related donor, and unrelated donor transplantation for Wiskott-Aldrich syndrome. The outcome of 170 transplantations for Wiskott-Aldrich syndrome, from 1968 to 1996, reported to the International Bone Marrow Transplant Registry and/or National Marrow Donor Program were assessed. Fifty-five were from HLA-identical sibling donors, 48 from other relatives, and 67 from unrelated donors. Multivariate proportional hazards regression was used to compare outcome by donor type and identify other prognostic factors. Most transplant recipients were younger than 5 years (79%), had a pretransplantation performance score greater than or equal to 90% (63%), received pretransplantation preparative regimens without radiation (82%), and had non-T-cell-depleted grafts (77%). Eighty percent received their transplant after 1986. The 5-year probability of survival (95% confidence interval) for all subjects was 70% (63%-77%). Probabilities differed by donor type: 87% (74%-93%) with HLA-identical sibling donors, 52% (37%-65%) with other related donors, and 71% (58%-80%) with unrelated donors (P =.0006). Multivariate analysis indicated significantly lower survival using related donors other than HLA-identical siblings (P =.0004) or unrelated donors in boys older than 5 years (P =.0001), compared to HLA-identical sibling transplants. Boys receiving an unrelated donor transplant before age 5 had survivals similar to those receiving HLA-identical sibling transplants. The best transplantation outcomes in Wiskott-Aldrich syndrome are achieved with HLA-identical sibling donors. Equivalent survivals are possible with unrelated donors in young children.

Actuarial Analysis↗

PubMed2001

Characterization of cytokine interactions by flow cytometry and factorial analysis.

BACKGROUND: Multiple cytokines are required for the growth and development of hematopoietic cells. The effect of many cytokines depends on the activity of other signaling pathways. These interactions are quantified using factorial experimental design and analysis. METHODS: Human umbilical cord blood (HUCB) CD34+ cells were cultured in fully defined media containing various combinations of recombinant cytokines as defined by resolution IV factorial (2(7-3)(IV)) or full factorial (2(4)) design experiments. The cytokines studied were stem cell factor (SCF), interleukin (IL)-3, megakaryocyte growth and development factor (MGDF), granulocyte-colony stimulating factor (G-CSF), Flt-3 ligand, IL-6, IL-11, and erythropoietin (EPO). In vitro cell divisions were tracked by staining CD34+ cells with 5-(and-6)-carboxyfluorescein diacetate, succinimidyl ester, followed by flow cytometric analysis at 4 days of culture. In separate experiments, lineage commitment and differentiation were determined at 7 days by immunophenotype. RESULTS: In addition to the main effects of single cytokines, cytokine interactions were identified. There was a negative interaction between IL-3 and MGDF that resulted in a less than additive effect of these factors on erythroid and megakaryocytic development. The effect of Flt-3 ligand and SCF factor on CD34+ cell production was also less than additive, although the response to both cytokines was greater than single cytokines. The only positive interaction that was identified was between EPO and SCF, which resulted in the synergistic production of erythroid cells. CONCLUSIONS: Factorial analysis provides a powerful methodology to study the integration of multiple signals at the cellular and molecular level.

Analysis of Variance↗

PubMed2000

Comparison of preparative regimens in transplants for children with acute lymphoblastic leukemia.

PURPOSE: Preparative regimens involving total-body irradiation (TBI) produce significant late toxicities in some children who receive bone marrow transplants, including impaired growth and intellectual development. Busulfan is often used as an alternative to TBI, but there are few data regarding its relative efficacy. PATIENTS AND METHODS: We compared outcomes of HLA-identical sibling transplants for acute lymphoblastic leukemia (ALL) in children (< 20 years of age) who received cyclophosphamide plus TBI (CY/TBI) (n = 451) versus those who received busulfan plus cyclophosphamide (Bu/CY) (n = 176) for pretransplant conditioning. Patients received transplants between 1988 and 1995 and their results were reported to the International Bone Marrow Transplant Registry by 144 participating institutions. The CY/TBI and Bu/CY groups did not differ in gender, immune phenotype, leukocyte count at the time of diagnosis, chromosome abnormalities, remission status, or length of initial remission. T-cell depletion was used more frequently in the CY/TBI group; the Bu/CY group included a higher proportion of children who were less than 5 years of age. The median follow-up period was 37 months. RESULTS: The 3-year probabilities of survival were 55% (95% confidence interval [CI], 50% to 60%) with TBI/CY and 40% (95% CI, 32% to 48%) with Bu/CY (univariate P =.003). The 3-year probabilities of leukemia-free survival were 50% (95% CI, 45% to 55%) and 35% (95% CI, 28% to 43%), respectively (univariate P =.005). In a multivariate analysis, the risks of relapse were similar in the two groups (relative risk [RR], 1.30 for Bu/CY v CY/TBI; P =.1). Treatment-related mortality was higher in the Bu/CY group (RR, 1.68; P =.012). Death and treatment failure (relapse or death, inverse of leukemia-free survival) were more frequent in the Bu/CY group (RR, 1. 39; P =.017 for death; RR, 1.42; P =.006 for treatment failure). CONCLUSION: These data indicate superior survival with CY/TBI conditioning, compared with Bu/CY conditioning, for HLA-identical sibling bone marrow transplants in children with ALL.

Adolescent↗

PubMed1999

Comparative study of the in vitro behavior of cord blood subpopulations after short-term cytokine exposure.

We investigated the effect of short-term cytokine exposure on defined cord blood subpopulations. CD34+Thy1+, CD34+Thy1-, CD34+38-, CD34+38+, CD34+DR+, CD34+DR-, CD34+Rhodamine123 (Rh123)- and CD34+Rh123+ cells were incubated for 7 days in IMDM + 10% FCS + IL3 + IL6 + G-CSF + SCF (36GS) + flt3L. We evaluated LTHC-IC, immunophenotype and nucleated cell count for each cell population before and after cytokine exposure. Short-term exposure of CD34+38+, CD34+Thy1-, CD34+DR+, CD34+DR- and CD34+Rh123+ cells to 36GS causes a significant increase in cell number, whereas CD34+38-, CD34+Thy1+, and CD34+Rh123- cells show only a limited increase. CD34 status post cytokine incubation shows that CD34+38+, CD34+Thy1-, CD34+DR+, and CD34+Rh123+ fractions have a lower proportion of cells remaining CD34+ than CD34+38- CD34+Thy1+, CD34+DR- and CD34+Rh123- fractions. LTHC-IC analyses among input subpopulations show a higher frequency among CD34+38+, CD34+Thy1-, CD34+DR+, CD34+DR- and CD34+Rh123+ cells as compared with CD34+38-, CD34+Thy1+ and CD34+Rh123- cells. However, when LTHC-IC were evaluated after cytokine exposure, CD34+38-, CD34+Thy1+, and CD34+Rh123- cells showed a higher frequency of LTHC-IC as compared with other subpopulations. Addition of flt3L to 36GS doubled the numbers in all subpopulations without altering the proportion of CD34+ cells. Results suggest that CD34+38-, CD34+Thy1+ and CD34+Rh123- cells have a limited proliferative response to cytokines, the stem cell component of these populations is largely maintained and that expansion is derived from mature cell populations.

Cell Culture Techniques↗

PubMed1997

Cytokine mediated expansion of human umbilical cord blood CD34+ cells: comparison of the use of partially purified and pure CD34+ target cells.

To determine the optimal cell population for cytokine mediated expansion, we compared the use of Magnetic Cell Sorting (MACS) system enriched CD34+ human umbilical cord blood (HUCB) cells with that of MACS enriched, flow purified CD34+ HUCB cells. Both MACS enriched CD34+ cells and MACS enriched, flow purified CD34+ cells (mean starting purity of CD34+ SC 51.27 +/- 7.6% and 96.36 +/- 1.34% respectively n = 6) were incubated for seven days with Interleukin-1 (IL-1) + IL-3 + Stem Cell Factor (SCF) and showed a fold increase in the number of nucleated cells (10.02 +/- 2.6 and 18.23 +/- 4.73 respectively) and a reduction in the percentage of CD34+ cells (5.55 +/- 1.23% and 12.21 +/- 3.29% respectively). An increase in the absolute numbers of CD34+ cells (4.8 x 10(4) +/- 2.3 x 10(4)) was observed with MACS enriched CD34+ cells as compared to no change (1.3 x 10(5) +/- 8.8 x 10(4) with MACS enriched, flow purified CD34+ cells. An increase in IL-3 + GM-CSF + SCF responsive colony forming unit (CFU) (1.7 x 10(4) +/- 9.4 x 10(3) and 1.6 x 10(5) +/- 7.7 x 10(4) respectively) was also observed as compared with input values (1.5 x 10(4) +/- 1 x 10(4) and 2.3 x 10(4) +/- 8.9 x 10(3) respectively). We conclude that MACS enriched, flow sorted CD34+ HUCB cells have greater cytokine mediated expansion potential as measured by progenitor expansion, than MACS enriched CD34+ HUCB cells.

Antigens, CD34↗

PubMed1996

Conditions affecting the isolation of human umbilical cord blood CD34+ cells.

The magnetic cell sorting (MACS) system was used to isolate CD34+ human umbilical cord blood (HUCB) stem cells (SC). Variables that might affect the detection of CD34+ cells, purity, enrichment, and yield of CD34+ cells, and the co-expression by CD34+ cells of CD38 and HLA-DR and their clonogenic capabilities were investigated. These variables were (a) separation technique [Ficoll, Percoll mononuclear cell (MNC) preparation] and (b) storage of HUCB [fresh, stored overnight (O/N) at 4 degrees C or frozen]. There was no difference between MNC prepared for MACS CD34+ SC isolation by Ficoll or Percoll separation. The use of fresh, O/N, or frozen HUCB did not affect the isolation of CD34+ SC.

Antigens, CD34↗

PubMed1996

Cure of X-linked lymphoproliferative disease (XLP) with allogeneic hematopoietic stem cell transplantation (HSCT): report from the XLP registry.

Seven male patients in the David T Purtilo International X-linked Lymphoproliferative Disease (XLP) Registry have undergone allogeneic hematopoietic stem cell transplantation (HSCT). All patients received HSCT from HLA-identical donors: sibling BM, five; unrelated BM, one; and sibling umbilical cord blood, one. Ages at time of HSCT ranged from 5 to 30 years. Pre-HSCT clinical course varied, but four boys had a significant history of chronic and/or serious infections. Conditioning regimens varied: TBI containing regimens, four, chemotherapy only, three. All patients engrafted. Six developed grade I-II acute GVHD but no chronic GVHD. Four are alive and well with normal immune function greater than 3 years following HSCT. Three died within 100 days: disseminated adenovirus, one; polymicrobial sepsis, one; and multiple organ system failure and bleeding diathesis, one. No EBV-associated post-transplant complications were observed, even though all donors except the umbilical cord blood were EBV-seropositive. Unsuccessful HSCT was associated with age at HSCT (> 15 years), TBI-containing regimen and significant history for pre-HSCT infections. These results provide evidence that HSCT performed during childhood with HLA-identical sibling donors, regardless of EBV serostatus, offers the only curative therapy for XLP.

Adolescent↗

PubMed1994

Spontaneous Clostridium septicum myonecrosis in congenital neutropaenia.

Spontaneous Clostridium septicum myonecrosis is an uncommon disorder that has been described in association with malignancy, immunosuppression and neutropaenia. Typical clostridial myonecrosis develops without a visible portal of entry and mortality is high. The pathogenesis is not completely understood but the clostridia may gain access to the circulation via areas of ileo-caecal ulceration secondary to enterocolitis, antibiotics or neoplasms. A 5 year old boy with congenital neutropaenia presented with spontaneous Clostridium septicum myonecrosis in the thigh. Limb salvage was achieved using antibiotics, hyberbaric oxygenation and selective debridement. The portal of entry may have been the gastrointestinal tract as colonic ulceration may occur in neutropaenia, and pre-morbid clindamycin administration may have encouraged overgrowth of colonic clostridia.

Anti-Bacterial Agents↗

PubMed1994

HLA non-identical T-cell-depleted bone marrow transplantation for primary immunodeficiency diseases.

BACKGROUND: Bone marrow transplantation (BMT) is usually the only procedure offering cure for children with life-threatening immune deficiency disorders, but compatible sibling donors are frequently unavailable. AIMS AND METHODS: To examine the outcome of HLA non-identical T-cell-depleted BMT carried out between April 1985 and May 1992 in 11 patients with primary immunodeficiency diseases and to seek prognostic factors. RESULTS: Eight patients achieved sustained engraftment, one after a second BMT. One further patient engrafted transiently, but rejected the graft five months later. Acute graft-versus-host disease (GVHD) grade II was seen in one and chronic GVHD was seen in three children. Seven patients survived beyond six months, six with donor T cell and five with donor B cell engraftment. At present, five patients (46%) are alive with immune reconstitution at a median follow-up of 14 months (range 6 to 78 months). The major factor associated with outcome was the presence of any infection within one week of BMT (p = 0.01). The presence of lung infection also tended to be a poor prognostic factor (p = 0.06) but did not reach significance, presumably because of the small sample size. HLA non-identical (parental) T-cell depleted BMT plays an important role in the cure of children with immunodeficiencies who do not have an identical sibling donor. Survival can be further improved if the diagnosis of immunodeficiency disease is made early and BMT undertaken before significant infections occur. CONCLUSIONS: The availability of T-cell depleted haploidentical parental bone marrow transplant can be anticipated to improve outcome significantly for children with severe immunodeficiency, especially when diagnosed early.

Bone Marrow Transplantation↗

PubMed1993

Local failure in childhood rhabdomyosarcoma and undifferentiated sarcoma: prognostic factors and implications for curative therapy.

In this retrospective review, the risk factors for local failure in childhood rhabdomyosarcoma and undifferentiated sarcoma were assessed in 49 patients managed by a multi-disciplinary team at the Prince of Wales Children's Hospital, Sydney, between 1970 and 1988. Average follow-up time was 6.1 years. Sixteen of 49 patients experienced local failure defined as local recurrence after complete excision (5/20) or progressive local disease following incomplete resection (11/29). Fourteen of 16 patients who experienced local failure have died. Using logrank analysis of time to local failure, we found significantly increased risk with "non-embryonal" histology (P = 0.032), residual tumour (P = 0.052, higher IRS group (P = 0.088), "inadequate radiotherapy" for residual tumour (P = 0.001), delay in definitive local treatment (P = 0.038) and Adriamycin-containing chemotherapy (P = 0.017). When these factors were examined by multivariate analysis (Cox regression), only the presence of residual tumour after resection, "inadequate radiotherapy" for residual tumour (P < 0.001), and delay in definitive local therapy (P < 0.037) were shown to have independent significant association with local failure. We conclude that local failure may be avoided by prompt local treatment by either complete surgical resection or adequate radiotherapy.

Adolescent↗

PubMed1993

Factors affecting hair regrowth after bone marrow transplantation.

Permanent alopecia after BMT has been reported as a side-effect associated with GVHD or after busulphan conditioning therapy, primarily in adults. We have reviewed children undergoing BMT to document the frequency of incomplete hair regrowth and to evaluate factors associated with this problem. Hair regrowth was studied in 74 children who survived > 6 months following BMT undertaken for malignant and non-malignant diseases. Alopecia was categorised as severe (< 50% of pre-transplant status), moderate (50-75%) or mild (> 75% but less than normal). Overall, 18 (24.3%) of 74 patients had mild (n = 5), moderate (n = 4) or severe (n = 9) alopecia. Risk factors for alopecia were presence of chronic GVHD (67%; p < 0.001), older age (p < 0.001) and prior cranial irradiation (42%; p = 0.03). Alopecia occurred in children receiving either busulphan (31%) or total body irradiation (16%; p = 0.15) as conditioning therapy. The highest frequency was seen in patients conditioned with busulphan with or without melphalan and who received prior cranial irradiation and/or developed chronic GVHD (75%). These data indicate that alopecia after BMT in children is a significant problem and confirm, in children, the previously noted association between alopecia and chronic GVHD and busulphan. Further risk factors of older age and prior cranial irradiation are identified. Consideration needs to be given to the use of an alternative to busulphan in children who are of older age, have received prior cranial irradiation and/or are at increased risk of GVHD.

Adolescent↗

PubMed1993

Role of second bone marrow transplants.

Fifteen patients with leukaemia and myelodysplasia (n = 10) or non-malignant disease (5) received a second and one a third BMT following recurrence of malignancy (7), rejection (5) or failure of engraftment (4). Of seven patients retransplanted for relapse, 3 of 3 who were conditioned with total body irradiation (TBI) for the first and chemotherapy for the second BMT relapsed whereas 0 of 4 who were conditioned with busulphan (BU) and CY for the first and TBI and melphalan for the second BMT relapsed. Three of these patients survive disease-free for longer than the remission after first BMT. Four patients with non-malignant disease received a second allogeneic BMT following failure of sustained engraftment and three are well and disease free for 24-75 months. Five patients received an autologous rescue because of failure of sustained engraftment. Three had sustained marrow recovery, with two patients surviving (one free of leukaemia and one with thalassaemia major), 41 and 77 months post-BMT. It is concluded that second allogeneic BMT can lead to prolonged disease-free survival and that TBI/melphalan may be a suitable conditioning therapy for second BMT in patients relapsing after BU/CY. Collection of an autologous back-up provides an additional safety measure in patients at increased risk of failure of sustained engraftment.

Adolescent↗

PubMed1992