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D Gallardo

Publications and source records attributed to D Gallardo.

At least 37 records · Page 2Linked to original sources
PubMed1999

Monoclonal antibody to HER-2/neureceptor modulates repair of radiation-induced DNA damage and enhances radiosensitivity of human breast cancer cells overexpressing this oncogene.

The management of human breast cancer frequently includes radiation therapy as an important intervention, and improvement in the clinical efficacy of radiation is desirable. Overexpression of the HER-2 growth factor receptor occurs in 25-30% of human breast cancers and correlates with poor clinical outcome, including earlier local relapse following conservative surgery accompanied by radiation therapy. In breast cancer cells with overexpression of HER-2 receptor, recombinant humanized monoclonal antibodies (rhuMAbs) to HER-2 receptors (rhuMAb HER-2) decrease cell proliferation in vitro and reduce tumor formation in nude mice. Therapy with rhuMAb HER-2 enhances tumor sensitivity to radiation at doses of 1-5 Gy, exceeding remission rates obtained with radiation alone. This benefit is specific to cells with HER-2 overexpression and does not occur in cells without overexpression. Treatment of cells with radiation (2-4 Gy) alone provokes a marked increase in unscheduled DNA synthesis, a measure of DNA repair, but HER-2-overexpressing cells treated with a combination of rhuMAb HER-2 and radiation demonstrate a decrease of unscheduled DNA synthesis to 25-44% of controls. Using an alternate test of DNA repair, i.e., radiation-damaged or undamaged reporter DNA, we introduced a cytomegalovirus-driven beta3-galactosidase into HER-2-overexpressing breast cancer cells that had been treated with rhuMAb HER-2 or control. At 24 h posttransfection, the extent of repair assayed by measuring reporter DNA expression was high after exposure to radiation alone but significantly lower in cells treated with combined radiation and rhuMAb HER-2 therapy. To further characterize effects of rhuMAb HER-2 and the combination of antibody and radiation on cell growth, analyses of cell cycle phase distribution were performed. Antibody reduces the fraction of HER-2-overexpressing breast cancer cells in S phase at 24 and 48 h. Radiation treatment is also known to promote cell cycle arrest, predominantly at G1, with low S-phase fraction at 24 and 48 h. In the presence of rhuMAb HER-2, radiation elicits a similar reduction in S phase at 24 h, but a significant reversal of this arrest appears to begin 48 h postradiation exposure. The level of S-phase fraction at 48 h is significantly greater than that found at 24 h with the combined antibody-radiation therapy, suggesting that early escape from cell cycle arrest in the presence of antireceptor antibody may not allow sufficient time for completion of DNA repair in HER-2-overexpressing cells. Because it is well known that failure of adequate p21WAF1 induction after DNA damage is associated with failure of cell cycle arrest, we also assessed the activity of this critical mediator of the cellular response to DNA damage. The results show induction of p21WAF1 transcripts and protein product at 6, 12, and 24 h after radiation treatment; however, increased levels of p21WAF1 transcript and protein are not sustained in HER-2-overexpressing cells exposed to radiation in the presence of rhuMAb HER-2. Although transcript and protein levels increase at 6-12 h, they are both diminished by 24 h. Levels of p21WAF1 transcript and protein at 24 h are significantly lower than in cells treated by radiation without antibody. A reduction in the basal level of p21WAF1 transcript also occurred after 12-24 h exposure to antibody alone. The effect of HER-2 antibody may be related to tyrosine phosphorylation of p21WAF1 protein. Tyrosine phosphorylation of p21WAF1 is increased after treatment with radiation alone, but phosphorylation is blocked by combined treatment with antireceptor antibody and radiation. This dysregulation of p21WAF1 in HER-2-overexpressing breast cells after treatment with rhuMAb HER-2 and radiation appears to be independent of p53 expression levels but does correlate with reduced levels of mdm2 protein. (ABSTRACT TRUNCATED)

Animals↗
PubMed1999

Clinical, radiographic and HLA associations as markers for different patterns of psoriatic arthritis.

OBJECTIVE: The aim of this study was to examine whether the five clinical forms of psoriatic arthritis (PsA) identified by Moll and Wright (Semin Arthritis Rheum 1973;3:55-78) could be clearly distinguished, especially as the disease evolved over time, to analyse whether radiographic features or HLA associations could define subsets with greater precision and to identify predictors of disease outcome. METHODS: Seventy-three patients (37 males and 36 females) were followed for a median time of 8 yr (range 1-16 yr). A standard clinical protocol was used to assess patients at each visit and two clinical scores. based on the joint areas involved, were defined to evaluate the mode of onset and the evolution of arthritis. X-ray films of the hands, feet and sacroiliac joints were taken and the patients were divided into two categories according to the presence or absence of erosions and an X-ray erosion score was also used. Three classification methods were used to define the different clinical subsets. HLA-A, B and DR antigens were tested by standard microlymphocytotoxicity assays. A multiple linear regression model was used in the statistical analysis. RESULTS: The five classical clinical subsets defined by Moll and Wright did not remain since distinct peripheral arthritis patterns tended to evolve over time. Only two discrete groups were identified, axial disease (AD) (sacroilitis with or without peripheral arthritis) in 29% of cases and peripheral disease (PD) without sacroilitis in 71%. AD was positively associated with the duration of arthritis (P < 0.04), presence of mutilation (P < 0.02) and the joint area score over disease evolution (JASE) (P < 0.02). There were erosions in 71% of the patients. Erosions correlated with the presence of mutilation (P < 0.007) and with the JASE (P < 0.0005). HLA-B27 was found in 43% of patients with AD, but only in 11% of PD patients (P < 0.01). No other clear HLA correlations were found. CONCLUSIONS: Despite the relatively small number of patients, this longitudinal study suggests that only two clinical subsets can be clearly defined in PsA, AD and PD; these are primarily determined on clinical grounds although HLA-B27 is strongly associated with AD. The evolution of PD pattern with time means that narrower peripheral arthritis subsets are of little clinical use.

Activities of Daily Living↗
PubMed1998

Mutation detection and typing of polymorphic loci through double-strand conformation analysis.

Variations, such as nucleotide substitutions, deletions and insertions, within genes can affect the function of the gene product and in some cases be deleterious. Screening for known allelic variation is important for determining disease and gene associations. Techniques which target specific mutations such as restriction enzyme polymorphism and oligonucleotide probe or PCR primer reactivity are useful for the detection of specific mutations, but these techniques are not generally effective for the identification of new mutations. Approaches for measuring changes in DNA conformation have been developed, based on the principle that DNA fragments which differ in nucleotide composition exhibit different mobilities after separation by polyacrylamide gel electrophoresis (PAGE). Here we describe a conformation-based mutation detection system, double-strand conformation analysis (DSCA), which provides a simple means to detect genetic variants and to type complex polymorphic loci. We demonstrate the application of DSCA to detect genetic polymorphisms such as a single-nucleotide difference within DNA fragments of up to 979 base pairs in length. We present the application of DSCA in detecting four different mutations in the cystic fibrosis gene (CFTR) and 131 different alleles encoded by HLA class I genes.

DNA↗
PubMed1998

A high resolution HLA class I and class II matching method for bone marrow donor selection.

HLA matching in bone marrow transplantation has an important role in determining successful outcome. However HLA typing of both potential related and unrelated donors can be both time-consuming and laborious, and does not always resolve accurately the true level of histocompatibility. We have utilised a method, reference strand mediated conformation analysis (RSCA), which is technically simple and allows high resolution matching for all HLA loci, for the typing of 48 patients and their potential 120 donors. The results indicate that RSCA can detect many mismatches that are not routinely identified by conventional HLA typing methods. In addition, RSCA can be applied for the simultaneous analysis of multiple potential BM donor samples in order to quickly identify the best match for each patient.

Alleles↗
PubMed1998

IL-6 and IL-8 levels in plasma during hematopoietic progenitor transplantation.

BACKGROUND AND OBJECTIVE: The relationship between cytokine concentrations and transplant-related complications has been studied in bone marrow transplant patients. The changes in TNF-alpha, IL-1 and IL-6 concentrations after transplantation are well documented in the literature but this is not the case for IL-8. The purpose of the present study was to investigate prospectively the plasma concentration of these cytokines and their relationship to transplant-related complications. DESIGN AND METHODS: Pro-inflammatory cytokine (TNF-alpha, IL-1, IL-6 and IL-8) levels in plasma were determined in a group of 53 patients undergoing hematopoietic progenitor transplantation. Plasma samples were collected weekly from day -7 to day +35 and stored at -70 degrees C until assayed by ELISA. The major transplant-related toxicities registered were: veno-occlusive disease (VOD), acute graft-versus-host disease (GVHD), infectious episodes, renal failure and mucositis. RESULTS: In spite of the great variability of plasma cytokine profiles between the different patients, we came to various conclusions. Patients' TNF-alpha and IL-1 concentrations correlated well over time. IL-6 and IL-8 profiles were similar and correlated well with febrile episodes. In some cases, an increase in IL-6 preceded hematologic recovery. In our study, increased levels of TNF-alpha, IL-6 and especially IL-8 correlated with hepatic or renal dysfunction as evaluated by increased bilirubin and creatinine in plasma, while pulmonary complications correlated only with increased IL-6 levels. Allogeneic transplant patients had a tendency to have higher TNF-alpha concentrations than autologous transplant patients, probably because an allogeneic transplant is associated with more transplant-related toxicity. Basal disease usually had no effect on cytokine profiles. INTERPRETATION AND CONCLUSIONS: IL-6 and IL-8 were the only cytokines studied whose increase correlated with febrile episodes. High IL-8 values may be a useful predictor of renal dysfunction and pulmonary disease and seems to trigger off high IL-6 levels. Plasma TNF-alpha and IL-1 concentrations during the posttransplant period have not been shown to be predictive of the development of transplant-related complications, and none of the profiles was recognized to be specific for a particular complication in this study.

Adolescent↗
PubMed1997

Low-dose donor CD8+ cells in the CD4-depleted graft prevent allogeneic marrow graft rejection and severe graft-versus-host disease for chronic myeloid leukemia patients in first chronic phase.

Based on previous experiences in animals and humans, low doses of CD8+ lymphocytes infused together with the marrow graft seem to enhance engraftment after allogeneic T cell-depleted marrow transplantation. From April 1994 to February 1997, 12 patients with chronic myelogenous leukemia in first chronic phase receiving a bone marrow transplant (BMT) from an HLA-identical sibling were included in a pilot study of T cell subset depletion. Total depletion of CD4+ cells of the marrow graft and partial depletion of CD8+ cells was performed by immunomagnetic separation. In order to improve the engraftment rate, we infused a low fixed number of CD8+ lymphocytes (0.25 x 10(6)/kg). All the patients were at high risk of developing acute graft-versus-host disease (GVHD), with a recipient age of >30 years, and/or donor sensitized by previous pregnancies or transfusions. All of them received cyclosporin A and methotrexate post-BMT. No graft failure was observed. The grade III-IV GVHD rate was 16.6%, and the actuarial survival at 3 years is 81.8%. Immunological recovery showed persistent CD8+ HLA-DR+ lymphocytosis 8 months after transplant. Relapses were not observed. This experience shows the importance of CD8+ cells to ensure correct engraftment, decreasing the GVHD rate.

Adult↗
PubMed1997

Pentoxifylline, ciprofloxacin and prednisone failed to prevent transplant-related toxicities in bone marrow transplant recipients and were associated with an increased incidence of infectious complications.

TNF-alpha (Tumor necrosis factor-alpha) is involved in many immunological and inflammatory processes, and might be expected to play an important role in the development of BMT-related complications. Triple therapy (pentoxifylline, ciprofloxacin and prednisone) with known anti-TNF activity was tested in 37 patients undergoing a hematopoietic progenitor transplant (HPT). A control group of 16 patients with similar characteristics was selected among consecutive patients receiving a HTP in a neighboring center who did not receive anti-TNF prophylaxis. Major transplant-related complications were registered (VOD, acute GVHD, infectious episodes, renal failure and mucositis) and survival status. TNF plasma concentrations were determined by ELISA, and pentoxifylline plasma concentrations were determined by HPLC. Among patients treated with pentoxifylline (PTX), ciprofloxacin and steroids, no difference in the mean survival time was observed compared with the control group. The incidence of procedure-related death up to day +35 was 11% in the study group and 6% in the control group. In spite of a tendency to a lower incidence of mucositis there was a higher incidence of infections (positive blood cultures) in the study group (49%) than in the control group (16.7%) (P = 0.16). This difference achieved statistical significance in patients receiving an allogeneic HPT (P = 0.05). It is likely that the use of steroids in the early period after transplant increases infectious episodes and makes control of GVHD difficult. The combined administration of steroids with pentoxifylline and ciprofloxacin has not proved beneficial in preventing mucositis, renal failure, VOD or GVHD, or in improving patient survival.

Adolescent↗
PubMed1996

Adenovirus-based transfer of wild-type p53 gene increases ovarian tumor radiosensitivity.

The p53 tumor suppressor gene product is known to be active in mediating radiation-induced G1-S cell cycle arrest and apoptosis in a number of normal cell lines. These functions are compromised by inactivation of p53, which promotes tumor progression. Because the p53 gene appears to play an important role in the cellular response to radiation, wild-type p53 gene replacement might be expected to increase the sensitivity of malignant cells with mutant p53 to the cytotoxic effects of ionizing radiation. This study demonstrates that adenovirus (AdV)-mediated transfer and expression of the wild-type p53 in malignant cells lacking the p53 gene results in an increase in cellular radiosensitivity in vitro and tumor radioresponsiveness in vivo. Cultures of the p53 double deletion mutant ovarian cell line SK-OV-3 were infected with nonreplicative adenoviral vectors containing either the wild-type p53 gene (AdVp53) or the luciferase gene (AdVluc). Cultures infected with AdVp53 efficiently expressed wild-type p53 protein and were more sensitive to radiation than uninfected cultures or cultures infected with AdVluc. The ability of AdVp53 to radiosensitize tumors in vivo was tested using SK-OV-3 tumors growing in the flanks of severe combined immune-deficient mice. Intratumoral injection with AdVp53, but not AdVluc, led to enhanced radioresponsiveness and 45% long-term tumor control. These studies demonstrate the ability of AdVp53 to effectively transfer and express p53 protein in established tumors with a resultant increase in radiation responsiveness.

Adenoviridae↗
PubMed1996

Neurologic complications after allogeneic bone marrow transplantation.

Neurological complications are not usually considered among the most important complications that may appear after allogeneic bone marrow transplantation (BMT). We have analyzed the occurrence of neurological manifestation in 27 recipients of allogeneic BMT. Ten patients (37%) developed neurological symptoms, and 14 episodes were registered. The most frequent manifestations were due to the use of cyclosporin A or prednisone for prophylaxis or treatment of graft-versus-host disease (GVHD). Cerebrovascular events (infarction or hemorrhage) and CNS infections were the most severe complications: they represented 26% of cause of death in our series. In conclusion, neurological complications are frequent in these patients, and represent an important cause of morbidity and mortality.

Bone Marrow Transplantation↗
PubMed1994

The human platelet alloantigens, HPA-5(a+, b-) and HPA-5(a-, b+), are associated with a Glu505/Lys505 polymorphism of glycoprotein Ia (the alpha 2 subunit of VLA-2).

GP Ia/IIa (also called VLA-2 or alpha 2 beta 1) is the primary receptor for collagen on platelets. The human platelet alloantigens HPA-5a(Brb) and HPA-5b(Bra) have been found to reside on the platelet GP Ia/IIa complex. In order to establish the molecular basis of the HPA-5 system, platelet RNA was isolated form HPA-5 (a+, b-) and HPA-5(a-, b+) individuals. After reverse transcription, cDNA coding for glycoprotein Ia (GP Ia) was amplified by the polymerase chain reaction (PCR). Nucleotide sequence analysis of the PCR products revealed an A-->G polymorphism at base pair 1648 of the coding region of the mature protein, resulting in a substitution of lysine (AAG) in HPA-5b(Bra) by glutamic acid (GAG) in HPA-5a(Brb) at amino acid 505. Subsequent PCR-ASRA (allele-specific restriction enzyme analysis) with Mnl I using cDNA derived from three HPA-5 (a+, b-), one HPA-5 (a+, b+) individuals demonstrated that HPA-5a and -5b alleles are distinguishable by DNA typing. In addition to the A-->G substitution at base pair 1648, three silent mutations were identified, G-->C (195 bp), C-->T (837 bp), G-->A (1041 bp).

Antigens, Human Platelet↗
PubMed1994

Cys209 Ser mutation in the platelet membrane glycoprotein Ib alpha gene is associated with Bernard-Soulier syndrome.

Molecular genetic analysis has been performed on a patient with Bernard-Soulier syndrome (BSS). The patient had characteristically giant platelets and was deficient in the glycoprotein (GP) Ib/IX/V complex, the von Willebrand factor (vWf) receptor on platelets. Previous studies with monoclonal antibodies directed against GP Ib alpha (CD 42b) and GP IX (CD 42a) demonstrated the absence of GP Ib alpha and presence of small amounts of GP IX on the surface of the patient's platelets. In this study the presence of GP V (CD 42d) is also demonstrated. This indicates a defect in the alpha-subunit of glycoprotein Ib. Therefore polymerase chain reaction (PCR)-amplification of the genomic DNA coding for GP Ib alpha was performed. Nucleotide sequence analysis of the entire coding region of GP Ib alpha revealed a homozygous single base pair mutation T-->A, leading to a single amino acid substitution cysteine-->serine at position 209 of the mature protein. We took advantage of the Mse I target site in the mutant allele, created by the T-->A mutation, to analyse all available family members. PCR-ASRA (allele-specific restriction enzyme analysis) using the restriction enzyme Mse I, revealed the heterozygosity of the mother and the two children of the patient, whereas homozygosity of the patient for the Cys209Ser mutation was confirmed. The sister of the patient was not found to be a carrier of the mutant allele. The mutation identified in the family studied, responsible for the deficiency of the GP Ib/IX/V complex, suggests that the cysteine at amino acid position 209 may be involved in disulphide bonding.

Adult↗