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Biomedical subjects

V T Ho

Publications and source records attributed to V T Ho.

At least 19 recordsLinked to original sources
PubMed2006

Quality of life associated with acute and chronic graft-versus-host disease.

Acute and chronic graft-versus-host diseases (GVHD) are associated with increased morbidity and mortality after hematopoietic stem cell transplantation (HCT). We prospectively measured the quality of life (QOL) of patients undergoing allogeneic transplantation. Ninety-six subjects completed self-assessment surveys before HCT, and at 6 and/or 12 months post-HCT that included the Medical Outcomes Study Short Form 12 (SF12) and the Functional Assessment of Cancer Therapy-Bone Marrow Transplant scale. Eighty-three percent of survivors responded at 6 and 12 months. Physical and mental functioning assessed by the SF12 was not associated with either acute or chronic GVHD. In contrast, the trial outcome index (TOI) of the Functional Assessment of Cancer Therapy-Bone Marrow Transplant was sensitive to occurrence of either acute or chronic GVHD. GVHD is a major determinant of the long-term QOL of survivors. The adverse effects of acute GVHD are detectable with the TOI at 6 months post transplantation after which development of chronic GVHD is the most strongly correlated with worse QOL.

Acute Disease↗
PubMed2006

HLA-C mismatch is associated with inferior survival after unrelated donor non-myeloablative hematopoietic stem cell transplantation.

HLA-C matching is an important determinant of outcome after myeloablative unrelated donor (URD) hematopoietic stem cell transplantation. However, its importance in non-myeloablative stem cell transplantation (NST) is not known. We report a retrospective analysis of 111 patients who underwent URD NST, of whom 78 were 10/10 matched at HLA-A, B, C, DRB1, DQB1 and 33 were mismatched at one or more HLA-C antigen/allele (24 HLA-C only; nine HLA-C+other locus mismatch). Patients were conditioned with busulfan (0.8 mg/kg/day i.v. x 4 days) and fludarabine (30 mg/m(2)/day i.v. x 4 days). Graft-versus-host disease prophylaxis included cyclosporine/prednisone- or tacrolimus/mini-methotrexate-based regimens. HLA-C disparity did not impair engraftment. Median marrow donor chimerisms were >or=90% donor at day+30 and +100 in both groups. Overall survival at 2 years was 30% in HLA-C-mismatched and 51% in 10/10-matched patients (P=0.008). In Cox regression, HLA-C mismatch was an independent predictor of death (hazard ratio 1.85, P=0.04). Treatment-related mortality was higher in the HLA-C-mismatched group: 48 versus 16% (P=0.0001). Cumulative relapse incidence was 35% in the HLA-C-mismatched and 55% in the 10/10-matched cohort, P=0.09. HLA-C mismatch is associated with inferior survival after URD NST.

Adolescent↗
PubMed2005

Routine screening for psychosocial distress following hematopoietic stem cell transplantation.

The diagnosis and treatment of cancer is often associated with high levels of psychosocial distress, yet exploration of these issues is rarely included in routine oncologic care. We conducted a pilot study to evaluate the feasibility of screening for psychosocial distress after autologous and allogeneic stem cell transplantation. A total of 80 adults were enrolled in Boston, MA, USA. Subjects completed self-administered assessments prior to hospital admission, at their first clinic visit after hospital discharge, and at 100 days post transplant. Assessments included validated instruments assessing psychosocial distress and quality of life (QOL). Elevated levels of anxiety and/or depression were detected in 55% of those providing pre-transplant assessments and were associated with compromised QOL. Post transplant screening was successfully performed in 69% of subjects and identified that 44% had symptoms of depression, anxiety or post traumatic stress disorder. Pre-transplant distress was associated with detection of distress after transplantation (81 vs 13%, P< 0.0001). In summary, we detected high levels of distress in transplant patients using self-administered tools. Pre-transplant distress appears to be highly predictive of distress post transplant and is a feasible marker to target screening and intervention programs.

Adaptation, Psychological↗
PubMed2004

Partial CD8+ T-cell depletion of allogeneic peripheral blood stem cell transplantation is insufficient to prevent graft-versus-host disease.

Prior studies suggest that depletion of CD8+ T cells from donor bone marrow or donor lymphocyte infusions can reduce graft-versus-host disease (GVHD) without compromising graft-versus-leukemia. We explored CD8 depletion in patients undergoing matched related donor (MRD, n=25) and unrelated donor (URD, n=16) peripheral blood stem cell transplantation following myeloablative conditioning with cyclophosphamide (60 mg/kg/day i.v. x 2) and total body irradiation (200 cGy x 7 fractions). Ex vivo incubation of mobilized donor peripheral blood cells with anti-CD8 antibody coated high-density microparticles removed 99% of CD8+ cells. The median number of CD8+ cells infused was 3.9 x 10(5) cells/kg (2.2 x 10(5) in MRD, and 8.1 x 10(5) in URD patients). Post transplant immune suppression included tacrolimus in the MRD cohort, and tacrolimus plus mini-methotrexate (5 mg/m2 days +1, 3, 6, 11) in the URD cohort. All 41 patients engrafted. Grade 2-4 acute GVHD incidence was 61% (44% MRD, 88% URD). Chronic GVHD incidence was 50% (48% MRD, 55% URD). Relapse incidence was 4.9%. Estimated event-free and overall survival rates were 65 and 63%, respectively, at 1 year and 56 and 57%, respectively, at 2 years. There was no correlation between CD8+ number and GVHD or survival. A 2-log depletion of CD8+ cells from PBSC is insufficient to prevent GVHD.

Adult↗
PubMed2003

The effect of hematopoietic growth factors on the risk of graft-vs-host disease after allogeneic hematopoietic stem cell transplantation: a meta-analysis.

The effect of hematopoietic growth factors on neutrophil recovery after allogeneic transplantation is well-recognized. Recent laboratory studies demonstrated that these cytokines may also modify T-cell and dendritic cell function, but whether the effect is strong enough to alter the risk of GVHD is unclear. We performed a meta-analysis to determine the effect of G-CSF or GM-CSF on the risk of nonhematopoietic outcomes after allogeneic transplantation. A search of the literature from 1986 to present yielded 18 publications in which data were provided for cohorts receiving growth factor vs either placebo or no therapy. These included nine prospective randomized studies, eight retrospective cohort studies, and one case-control study comprising a total of 1198 patients. The publication types were heterogeneous with regard to demographic and treatment characteristics, although within publications, comparative groups were generally balanced. The pooled risk ratio estimates with use of growth factor was 1.08 (95% CI 0.87-1.33, P=0.48) for grades 2-4 acute GVHD, 1.22 (95% CI 0.80-1.86, P=0.99) for grades 3-4 acute GVHD, and 1.02 (95% CI 0.82-1.26, P=0.87) for chronic GVHD. This analysis did not detect a significant change in the risk of acute or chronic GVHD after allogeneic hematopoietic stem cell transplantation when hematopoietic growth factors were used to shorten the initial period of neutropenia.

Bone Marrow Transplantation↗
PubMed2001

Prognostic factors for early severe pulmonary complications after hematopoietic stem cell transplantation.

Pulmonary complications are a significant cause of early mortality (before day 100) after bone marrow transplantation (BMT). To identify factors associated with development of early post-BMT severe pulmonary complications (SPCs), we conducted a retrospective review of the medical records of 339 consecutive patients who underwent hematopoietic stem cell transplantation for hematologic disorders and identified pulmonary complications that occurred before day 60 posttransplantation. SPCs, defined as (1) diagnosis of diffuse alveolar hemorrhage, (2) need for mechanical ventilation, or (3) death from respiratory failure, occurred in 48 (24%) of 199 patients receiving allogeneic transplants and 4 (2.9%) of 140 patients receiving autologous transplants (P < .001). Multiple clinical variables were analyzed to determine their influence on the development of SPCs in allogeneic marrow recipients. The method of graft-versus-host disease (GVHD) prophylaxis was the single most important factor affecting SPC incidence. Of patients who received cyclosporine/methotrexate (CYA/MTX) as GVHD prophylaxis, 33% experienced SPCs compared with 8% of those receiving T-cell depletion (TCD) alone (P < .0001). Multivariate analysis confirmed that TCD was associated with a lower risk of SPCs (relative risk [RR], 0.18; P = .0006). In addition to GVHD prophylaxis, a reduced pretransplantation FEV1 (forced expiratory volume in 1 second) (< or = 80% of predicted) was associated with an increased risk for SPCs (odds ratio, 4.4; P = .0025). Grades 2 to 4 acute GVHD, tobacco use, age > or = 50 years, sex, unrelated donor, cytomegalovirus serologic status, disease status at transplantation, pretransplantation carbon monoxide diffusing capacity, and total body irradiation were not associated with development of SPCs. We conclude that autologous BMT is associated with a significantly lower incidence of SPCs compared with allogeneic BMT and that for allogeneic BMT, GVHD prophylaxis using TCD is associated with a significantly lower risk for SPCs compared with prophylaxis using CYA/MTX. Patients with pretransplantation FEV1 of < or = 80% appear to have a higher risk for SPCs.

Adolescent↗
PubMed1998

Constitutional and mosaic large NF1 gene deletions in neurofibromatosis type 1.

A set of neurofibromatosis type 1 (NF1) patients was screened for large NF1 gene deletions by comparing patient and parent genotypes at 10 intragenic polymorphic loci. Of 67 patient/parent sets (47 new mutation patients and 20 familial cases), five (7.5%) showed loss of heterozygosity (LOH), indicative of NF1 gene deletion. These five patients did not have severe NF1 manifestations, mental retardation, or dysmorphic features, in contrast to previous reports of large NF1 deletions. All five deletions were de novo and occurred on the maternal chromosome. However, two patients showed partial LOH, consistent with somatic mosaicism for the deletion, suggesting that mosaicism may be more frequent in NF1 than previously recognised (and may have bearing on clinical severity). We suggest that large NF1 deletions (1) are not always associated with unusual clinical features, (2) tend to occur more frequently on maternal alleles, and (3) are an important mechanism for constitutional and somatic mutations in NF1 patients.

Adult↗
PubMed1997

Four frameshift mutations in neurofibromatosis type 1 caused by small insertions.

We have been using heteroduplex analysis to assay individual exons within the NF1 gene in an effort to identify disease causing constitutional mutations in neurofibromatosis type 1 patients. Here we report the identification and characterisation of four insertional NF1 frameshift mutations in an analysis of exons 28-39 in a set of 78 patients. These include three 1 base pair insertions and one 2 base pair insertion. Three of these mutations can be attributed to replication slippage errors, while the mechanism behind the fourth may be related to formation of secondary structure during replication. It may be of significance that a majority of the previously reported small insertions in NF1 also lie within exons 28-39.

Adult↗
PubMed1996

Effects of transition metals on the expression of the erythropoietin gene: further evidence that the oxygen sensor is a heme protein.

Both in vivo and in Hep3B cells, expression of the erythropoietin gene is induced by hypoxia as well as by certain transition metals (cobalt and nickel) and by iron chelation. When Hep3B cells were incubated in an iron deficient medium, Epo mRNA expression was enhanced 4-fold compared to Hep3B cells in iron enriched medium. The increased Epo expression in iron deficient medium was abolished when Fe2-transferrin complex was added. Epo induction by cobalt was also affected by iron concentration. In iron enriched medium, erythropoietin expression in Hep3B cells was maximally induced at CoCl2 concentrations between 100 to 200 microM. In contrast, in iron poor medium, a high level of induction was obtained at a CoCl2 concentration of only 50 microM, indicating competition between iron and cobalt. Under hyperbaric oxygen, cobalt induction of erythropoietin mRNA was modestly suppressed while nickel induction was markedly enhanced. These observations support the proposal that the oxygen sensor is a heme protein in which cobalt and nickel can substitute for iron in the porphyrin ring.

Carcinoma, Hepatocellular↗
PubMed1996

Somatic mosaicism in a patient with neurofibromatosis type 1.

Using loss of heterozygosity analysis, a method designed to detect moderate to large gene deletions, we have identified a new-mutation neurofibromatosis type 1 (NF1) patient who is somatically mosaic for a large maternally derived deletion in the NF1 gene region. The deletion extends at least from exon 4 near the 5' end of the gene to intron 39 near the 3' end. The gene-coding region is, therefore, mostly or entirely deleted, encompassing a loss of > or = 100 kb. We hypothesize that the deletion occurred at a relatively early developmental timepoint, since signs of NF1 in this patient are not confined to a specific body region, as seen in "segmental" NF, and since both mesodermally and ectodermally derived cells are affected. This report provides the first molecular evidence of somatic mosaicism in NF1 and, taken together with a recent report of germ-line mosaicism in NF1, adds credence to the concept that mosaicism plays an important role in phenotypic and genetic aspects of NF1 and may even be a relatively common phenomenon.

Adult↗
PubMed1996

CT and MR evaluation of a wooden foreign body in an in vitro model of the orbit.

We made an in vitro model of a wooden foreign body using both fresh and dry pine wood in both fat and soft-tissue background mediums. Air/wood/background medium interfaces were studied with MR and CT to determine which method provided the best image contrast for detecting a wooden foreign body. CT was demonstrated to be superior to MR in the evaluation of the orbit in the in vitro model.

Animals↗
PubMed1996

Intraorbital wooden foreign body: CT and MR appearance.

A case of an intraorbital wooden foreign body mimicking air on standard CT window setting and on MR is presented. Its higher attenuation with higher CT window setting as well as its elongated and well-delineated shape on both CT and MR helped to distinguish it from air.

Child↗
PubMed1994

Postsurgical conjunctival epithelial cysts.

MR appearance of two patients with large, orbital conjunctival epithelium-lined inclusion cysts are presented. Both were complications of ophthalmic surgical procedures that necessitated conjunctival incision.

Adolescent↗
PubMedDate not supplied

CT of adenomas of the middle ear and mastoid cavity.

A case of mixed type adenoma of the middle ear and mastoid is presented in which CT showed complete opacification of the middle ear and mastoid air cells with bulging of the tympanic membrane but without ossicular or bony destruction.

Adenoma↗