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Biomedical subjects

M C Alonso

Publications and source records attributed to M C Alonso.

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

NK phenotypic markers and IL2 response in NK cells from elderly people.

Immunosenescence is a process that primarily affects the T cell compartment of the immune system, although age-associated immunological alterations have also been demonstrated in the NK cell phenotype and function. A significant expansion in the number of NK cells is found in aging. The NK cytotoxic capacity of total peripheral blood lymphocytes is also well preserved, not only in healthy elderly people but also in centenarians. However, NK cell killing of K562 is impaired when considered in a per-cell basis, and this defect is associated with defective signal transduction after activation more than a diminished conjugate formation or killing capacity. We have studied the phenotype of NK cells in elderly donors fulfilling the Senieur criteria. We have also studied the capacity of these cells to be activated by IL2 when different NK cell functions, other than cytotoxicity, are considered. Our results confirm the increased percentage of NK cells in the elderly due to the expansion of the CD56dim subset that also show an altered pattern of activation markers, whereas no differences were found in the CD56bright subset. The response of NK cells to IL2 was found to be impaired when proliferation, expression of CD69, and Ca2+ mobilization were considered, whereas TNF-alpha production was not significantly affected. These results suggest that human NK cells do not escape the aging process, although senescence have a differential effect on distinct NK cell biological functions, ranging from severe to negligible impairment, depending on the parameters considered.

Adult↗
PubMed1999

Natural killer cells in healthy aging.

Immunosenescence is a process that affects all cell compartments of the immune system. Age-associated changes have been demonstrated not only on T lymphocytes but also in different aspects of the innate immunity including natural killer (NK) cells. A significant expansion in the percentage of NK cells showing a mature phenotype has been found in healthy elderly donors, and the NK-cytotoxic capacity of total peripheral blood lymphocytes is well preserved in these individuals. However, NK-cell killing of K562 is impaired when considered on a per-cell basis. Furthermore, NK cells from elderly people show a decreased proliferative response to interleukin 2 and a parallel impaired expression of the CD69 activation antigen. The response to interleukin 2 of NK cells from aged donors is also impaired in terms of their capacity to kill NK-resistant cell lines, but not when K562 killing, perforin synthesis, or tumor necrosis factor alpha production are considered. Therefore phenotypic and functional alterations can be shown in NK cells in healthy aging. These changes are compatible with the expansion of a mature NK subset.

Aged↗
PubMed1999

Prevalence of BRCA1 and BRCA2 Jewish mutations in Spanish breast cancer patients.

We screened the 185delAG and 5382insC (BRCA1) and the 6174delT (BRCA2) mutation in 298 Spanish women with breast cancer. Two women (one with Sephardic ancestors) presented the 185delAG mutation and the same haplotype reported in Ashkenazim with this mutation. This suggests a common origin of the 185delAG in both Sephardic and Ashkenazi populations.

Adult↗
PubMed1999

Enumeration and isolation of viral particles from oligotrophic marine environments by tangential flow filtration.

A method for concentrating, enumerating and isolating viral particles from marine water samples was developed and evaluated. The method consists of a concentration step by a tangential flow filtration (TFF) system, ultrafiltration by centrifugal concentrator, and visualization by transmission electron microscopy (TEM). This procedure allows to reduce volumes of ca. 21 of seawater to 10-20 microliters, which can be dispensed on electron microscopy grids to count total viral particles. This method allows the recovery of small numbers of viral particles from oligotrophic seawater samples, in which viral numbers ranged from 10(5) to 10(6) viral particles/ml. The tangential flow filtration system was evaluated as quantitative technique using suspensions of two different bacteriophages (T6 and phi X174) in autoclaved seawater. Recovery rates varied depending on both the viral morphology and flow rate; recovery percentages reached 117.4% for T6 and 60.6% for phi X174 using low flow rate.

Adsorption↗
PubMed1998

Proteolytic mapping of kinesin/ncd-microtubule interface: nucleotide-dependent conformational changes in the loops L8 and L12.

We used a battery of proteases to probe the footprint of microtubules on kinesin and ncd, and to search for nucleotide-induced conformational changes in these two oppositely-directed yet homologous molecular motors. Proteolytic cleavage sites were identified by N-terminal microsequencing and electrospray mass spectrometry, and then mapped onto the recently-determined atomic structures of ncd and kinesin. In both kinesin and ncd, microtubule binding shields a set of cleavage sites within or immediately flanking the loops L12, L8 and L11 and, in ncd, the loop L2. Even in the absence of microtubules, exchange of ADP for AMPPNP in the motor active site drives conformational shifts involving these loops. In ncd, a chymotryptic cleavage at Y622 in L12 is protected in the strong binding AMPPNP conformation, but cleaved in the weak binding ADP conformation. In kinesin, a thermolysin cleavage at L154 in L8 is protected in AMPPNP but cleaved in ADP. We speculate that ATP turnover in the active site governs microtubule binding by cyclically retracting or displaying the loops L8 and L12. Curiously, the retracted state of the loops corresponds to microtubule strong binding. Conceivably, nucleotide-dependent display of loops works as a reversible block on strong binding.

Adenosine Diphosphate↗
PubMed1998

Identification of the 185delAG BRCA1 mutation in a Spanish Gypsy population.

The 185delAG BRCA1 deletion occurs with a high frequency in Ashkenazi Jews. We detected this mutation in two Spanish Gypsy women (the only Gypsy participants) in an extensive study of 90 high-risk families and 160 women with early-onset breast cancer. One of these Gypsy women belonged to a high-risk family and the other had had early-onset breast cancer. The mutation was also detected in 1 out of 25 Gypsy samples unrelated to breast cancer. All the samples with the mutation shared the marker alleles present in Jewish samples with 185delAG. This is the first report of this mutation in a non-Jewish well-defined ethnic population. According to these findings the carrier frequency of this mutation in Gypsy individuals could be several times higher than that of the general population, and this should be taken into consideration in genetic screening for cancer in Gypsy populations.

Adult↗
PubMed1998

Severe immune thrombocytopenia during formestane treatment.

Formestane is a new aromatase inhibitor used as second-line endocrine treatment for postmenopausal women with advanced breast cancer. The most frequent side effects are local reactions. Here we report the development of immune thrombocytopenia coinciding with administration of this drug.

Androstenedione↗
PubMed1997

Epidermal growth factor in plasma and saliva of patients with active breast cancer and breast cancer patients in follow-up compared with healthy women.

We measure EGF in saliva and plasma from 52 patients with active breast cancer, 22 breast cancer patients in follow-up (non-active) and 33 healthy women. EGF concentrations in saliva were significantly higher in patients with active and non-active breast cancer than healthy women, whereas the opposite results were found in plasma. The highest values of EGF in saliva were found in the local recurrence subgroup.

Adult↗
PubMed1997

Prognostic value of S-phase fraction in lymph-node-negative breast cancer by image and flow cytometric analysis.

Cellular DNA content and proliferation rates have been suggested as prognostic factors in breast carcinomas. A series of 271 lymph-node negative breast carcinoma patients without adjuvant therapy was reviewed (mean follow-up, 108 mo). Tumor cells from the same paraffin-embedded block tissue (Hedley's method) were analyzed by image analysis (IA) in Feulgen-stained smears and by flow cytometric analysis (FC). Clinicopathologic features, ploidy, S-phase fraction, and percentage of tumor cells with more than 5n DNA content (in diploid tumors, by IA) were related to outcome. The results of IA and FC were compared in 115 cases. Tumor size, histologic grade, desmoplasia and S-phase fraction were significant predictors of survival in multivariate analysis (Cox proportionate regression) (P < or = 0.03). Ploidy by the two methods showed agreement in 100 carcinomas (87%). Of the 15 discordant cases, FC detected 6 multiploid and 4 aneuploid-peridiploid. In contrast, IA detected more tetraploid carcinomas. Tumor size, histologic grade, desmoplasia, and S-phase fraction were independent predictors of long-term prognosis in our patients. Ploidy and percentage of tumor cells with more than 5n DNA content were not prognostic indicators. FC detected aneuploidy more frequently than did IA.

Adult↗
PubMed1995

[High-dosage chemotherapy and the autologous transplantation of peripheral hematopoietic progenitor cells in breast cancer: the initial results, analysis of toxicity and the necessary support means].

BACKGROUND: In the last years high dose chemotherapy (HDC) schedules have been developed with autologous bone marrow transplantation (ABMT) which are very effective in breast cancer. Expectation has been raised concerning the cure of a subgroup of patients with metastatic breast cancer and the improvement of prognosis in high risk stages II and III. METHODS: CTCb (cyclophosphamide 6 g/m2, thiotepa 500 mg/m2 and carboplatin 800 mg/m2) was administered with autologous peripheral hematopoietic progenitor cells transplantation (TACPHP) and granulocytic colony stimulating factor (G-CSF) 5 micrograms/kg/day to 27 patients with breast cancer: 9 in stage IV in complete remission, 12 in stage II with > or = 10 affected lymph nodes and 6 in stage III. RESULTS: No toxic deaths were reported. The median time to achieve > or = 0.5 x 10(9) neutrophils/l was 8 days, to > or = 20 x 10(9) platelets/l 9 days and to > or = 50 x 10(9) platelets/l 12 days. Fever was observed in 85% of the patients although its median duration was of only one day. Extrahematologic toxicity was moderate with grade III nausea/vomiting in 48% of patients, grade III mucositis in 22%, grade III hepatitis in 19%, and grade III diarrhea in 4%. No grade IV toxicity was observed. The median follow-up is still short (10 months, range: 2-25). All the patients maintain normal hematologic peripheral blood counts and only 4 (in stage IV) have relapsed. CONCLUSIONS: The slight extrahematologic toxicity observed in the high dose chemotherapy with cyclophosphamide, thiotepa and carboplatin, and the rapid hematologic recovery provided by the TACPHP and G-CSF allow the above schedule to be administered with moderate toxicity and no mortality. This low toxic profile leads to the possibility of future trials with this chemotherapy schedule in other subgroups of patients with breast cancer.

Adult↗
PubMed1995

[10 Year follow up of chemotherapy and surgery on the second laparotomy in advanced ovarian cancer].

BACKGROUND: Advanced ovarian neoplasm has bad prognosis. There is little knowledge as to the effect of surgical and chemotherapy treatments on long-term survival. METHODS: Seventy-two patients with advanced epithelial ovary carcinoma (53 stage III and 19 stage IV) were treated according to a treatment regimen with reduction surgery, five cycles of chemotherapy with cyclophosphamide, adriamycin and cisplatin (CAP) followed by second revision laparotomy. RESULTS: The rate of response for the CAP schedule was 80%, of which 16 patients (23%) showed complete response (CR), 7 (10%) partial microscopic response (PMiR) and 33 (47%) partial macroscopic response (PMR). Complete resection of residual masses was performed on the second laparotomy in 14 of the 33 patients with parital response. The median survival for all the group was 36 months with overall actuarial survival of 27% at 10 years. The survival of the group of patients with CR was significantly longer than that of PMiR and other groups. Significant differences favorable for the group of partial response with second attempt radical surgery were found versus the group in which te second surgical resection was not radical. FIGO III stage and prechemotherapy tumor size less than 5 cm were found to have favorable effect in the rate of response and survival. CONCLUSIONS: The use of CAP chemotherapy achieved complete response in 23% of the patients studied. This group of patients showed to have a greater probability of longer survival. Second attempt surgery on the second laparotomy offers therapeutic benefits when radical.

Adult↗
PubMed1995

A phase III randomized trial of cyclophosphamide, mitoxantrone, and 5-fluorouracil (CNF) versus cyclophosphamide, adriamycin, and 5-fluorouracil (CAF) in patients with metastatic breast cancer.

One hundred patients with metastatic breast cancer were randomly selected to receive combined chemotherapy treatment with adriamycin (50 mg/m2) or mitoxantrone (12 mg/m2) associated with 5-fluorouracil (600 mg/m2) and cyclophosphamide (600 mg/m2) administered intravenously every 21 days with a maximum of ten cycles. All patients included in this study were under 75 years of age and had ECOG performance status of less than 4. They had not been treated previously with chemotherapy for metastatic disease. Patients treated with adjuvant chemotherapy, which could not have included anthracyclines, had to have relapsed at least 12 months after the completion of therapy. There were no statistically significant differences in pretreatment characteristics or metastatic disease location between the two groups. Ninety-four patients were assessable for response. No differences were observed in response rate or in survival between the groups. The response rate (complete response (CR) and partial response (PR)) was 68% (13% CR and 55% PR for CAF; 0% CR and 68% PR for CNF). Median survival for all patients was 19 months (18 months with CAF and 19 months with CNF). All patients were assessable for toxicity. There were no differences in gastrointestinal and cardiac toxicity. More grade I-II hematologic toxicity episodes (p < 0.001) and treatment delays (p = 0.05) due to leucopenia were observed with the CNF group, and more grade III alopecia (p < 0.001) was observed with the CAF group. Patients received further therapeutic manoeuvres after finishing the study with a sequential treatment consisting of hormonal therapy and chemotherapy with mitomycin (M) -vinblastine (Vbl) (M 10 mg/m2 day 1, Vbl 5 mg/m2 days 1, 15 and 29; maximum 5 cycles). This chemotherapy treatment was received by 32 patients, with a response rate of 34% and grade III-IV hematologic toxicity of 37%. Treatment with CNF can be considered a good alternative to CAF for first-line treatment of metastatic breast cancer. M-Vbl treatment is useful as second-line treatment in patients with prior adriamycin exposure.

Adult↗
PubMed1995

[Intensive chemotherapy with support of peripheral hematopoietic progenitor cells, mobilized with high-dose cyclophosphamide and G-CSF: fast hematologic recovery].

BACKGROUND: Hematopoietic progenitor cells mobilized to peripheral blood by a chemotherapy combined or not with hematopoietic growth factors and harvested with cyto-apheresis (CTA) provide a rapid hematological recovery when infused as a support step after intensive chemotherapy (IC). METHODS: Cyclophosphamide (CI) 4 g/m2 and G-CSF 5 mcg/kg/d were administered to 19 patients with a solid tumor or lymphoma. Daily CTA were performed during hematological recovery to harvest > 2.5 x 10(6) cells CD34+/kg. Seventeen patients received IC with infusion of peripheral hematopoietic progenitor cells (PHPC) and G-CSF. RESULTS: A total of 52 CTA were performed, with a median (M) of 2 per patient. A M of 4.4 x 10(8) mononucleated cells/kg and 9.8 x 10(6) CD34+/kg were harvested per patient. Hematological recovery after IC with support of PHPC and G-CSF was rapid in all cases, but the aplastic period was shorter in the ten patients who received > 5 x 10(6) CD34+/kg cells than in the seven patients with < 5 x 10(6) kg: The median of recovery to neutrophils > 0.5 x 10(9)/l was 8 days compared with 9 days (p = 0.0005), to platelets > 20 x 10(9)/l of 8 days compared with 12 days (p = 0.001), and to platelets > 50 x 10(9)/l of 11 days compared with 14 days (p = 0.001). CONCLUSIONS: Toxicity of IC (4 g/m2) with G-CSF is moderate and allows the harvesting of an adequate number of PHPC. Its infusion after IC provides a rapid hematological recovery, which was more marked in patients receiving 5 x 10(6) CD34+/kg cells, than with the same IC schedules of IC with autologous bone marrow transplantation.

Adult↗
PubMed1995

Endometrial cancer stages I and II. Analysis of survival and prognostic factors.

BACKGROUND: Endometrial cancer is the most frequent gynaecologic neoplasia in women. Stages I and II account for 75% of endometrial cancers. METHODS: Diagnostic features, treatment and outcome based on therapy with surgery and/or irradiation of 185 endometrial cancer patients in Stage I and II were analysed retrospectively. RESULTS: There were 148 patients (80%) in Stage I and 37 (20%) in Stage II. Twenty-nine patients (16%) relapsed and 18 have died of cancer. The 5 and 10 year specific actuarial survival was 89% and 81% respectively. The 5 and 10 years disease free survival was 82% and 78% respectively. In our analysis of prognostic factors we observed a significantly worse survival for postmenopausal and Stage II patients, high grade tumors (grade III) and greater myometrial penetration (outer 2/3). CONCLUSIONS: Endometrial cancer has a relatively good prognosis partly because of its early diagnosis. There is general consensus that surgery is the optimal treatment in Stages I and II. While it is well documented that complementary irradiation improves survival in Stage II, there is no general agreement regarding the value of complementary irradiation in Stage I. Further studies are needed to delimit Stage I patients who would benefit from complementary irradiation.

Adult↗
PubMed1994

Bacteriophages presence in human faeces of healthy subjects and patients with gastrointestinal disturbances.

The variation of the content of enteric bacteria and their bacteriophages in faeces from the different types of diarrhoeal processes has been studied. A total of 122 samples of human faeces from both healthy individuals and patients with diarrhoeal diseases of functional or infectious origin were tested. Detection rates for all microbial parameters tested decreased in the faeces of individuals with functional gastrointestinal disturbances. On the contrary, no significant differences of the microbial detection frequency was observed in faeces containing pathogenic microorganisms compared to faeces of healthy subjects. Human faeces were a poor source of F-specific, Salmonella, and Bacteroides bacteriophages, whereas specific Escherichia coli phages were isolated in most samples tested. Coliphage concentrations in faeces of healthy individuals were not directly correlated with levels of faecal coliforms. On the basis of their high correlation, faecal streptococci and coliphages were the most adequate indicators of the intestinal ecosystem variations in subjects with diarrhoeal processes.

Bacteriophages↗