PubMed Health⌕ Search

Biomedical subjects

A López

Publications and source records attributed to A López.

At least 19 recordsLinked to original sources
PubMed1995

DNA aneuploidy in acute myeloblastic leukemia is associated with a high expression of lymphoid markers.

In the present study the DNA cell content of 205 de novo acute myeloblastic leukemia (AML) patients is analyzed at flow cytometry in order to determine both the incidence of DNA aneuploidy in AML patients and the clinical and biological characteristics of AML aneuploid cases. All technical procedures were performed in accordance with the proposed guidelines of the DNA Cytometric Consensus Conference. Our results show that the incidence of DNA aneuploidy is quite low (4.8%), with most cases (n = 8) hyperdiploid and only a small proportion (n = 2) hypodiploid. No major differences were detected between the aneuploid and diploid cases with respect to the clinical and prognostic disease characteristics. Regarding the immunophenotype of the blast cells, the aneuploid cases displayed both a higher incidence of immature myeloblastic phenotype and a greater expression of lymphoid-associated antigens. In summary, our results show that AML patients display a quite low incidence of DNA aneuploidy and that despite the fact that these cases do not display particular clinical characteristics, they show an association with the expression of lymphoid-related markers.

Adult↗
PubMed1995

Chronic idiopathic thrombocytopenic purpura in the elderly.

From a group of 118 patients with chronic idiopathic thrombocytopenic purpura (ITP), 43 were older than 60 years at diagnosis. In this report, we describe the clinical evolution and therapeutic response in young and old patients. The overal rate of hemorrhagic manifestations was similar in the two age groups, but a greater risk for severe bleeding was observed in elderly patients. There were no significant differences between old and young patients in response to steroids. In none of our patients was mortality associated with bleeding or side effects of the treatment. In conclusion, we have observed a more benign clinical course in elderly patients with chronic ITP as compared to previous reports.

Adolescent↗
PubMed1995

Spatial interaction between neighbouring counties: cancer mortality data in Valencia Spain.

The statistical analysis of geographical mortality data has usually been approached via regression models that include appropriate covariates. These models assume stochastic independence of mortality counts for neighbouring sites, a questionable assumption that spatial automodels (Besag, 1974, Journal of the Royal Statistical Society, Series B 36, 192-236) make unnecessary. This paper presents the use of the autopoisson distribution in order to detect spatial interaction between neighbouring sites. If this interaction results in being nonsignificant, the auto-Poisson distribution reduces to a usual Poisson regression model, a particular case of generalized linear models (McCullagh and Nelder, 1989, Generalized Linear Models, 2nd edition. London: Chapman and Hall) which can be analyzed with the GLIM package.

Colonic Neoplasms↗
PubMed1993

Lymphoid subsets in acute myeloid leukemias: increased number of cells with NK phenotype and normal T-cell distribution.

Natural killer (NK) and T subsets were analyzed with appropriate dual labeling by flow cytometry in peripheral blood (PB) (66 cases) and bone marrow (BM) (55 cases) from patients with de novo AML in order to determine: (a) their distribution at diagnosis, (b) the correlation between PB and BM in NK subpopulations, (c) their relationship with the clinical and hematological disease characteristics, and (d) the changes occurring upon achieving complete remission (CR). NK cells defined by the expression of CD56 in the absence of CD3 were significantly increased at diagnosis and their levels in PB correlated with those of BM. By contrast, NK subsets defined by CD16 expression (CD16+ CD2+ and CD16+ CD2- NK-cell subsets) as well as T lymphocytes with NK activity (CD56+ CD3+), although increased in PB, displayed normal levels in BM. An additional observation of interest was the expansion of an immature NK population lacking CD16 Ag expression (CD56+ CD16-). AML cases were divided into two groups according to the absolute number of NK cells in PB; patients with the highest levels showed an increased proportion of blast cells in PB (p = 0.01), monocytic subtypes (p = 0.03), and expression of CD11b, CD14, and CD4 antigens (p = 0.05). Infections at diagnosis were not related to the level of NK cells. In 19 patients who achieved complete remission the number of CD56+ CD3- cells tended to be reduced to within the normal range. Other T-cell populations, including the CD4 naive and memory cells, were also explored, their distribution being normal in the PB of AML patients. By contrast, the cytotoxic subset CD8+/CD57+ was significantly increased (p < 0.001). These data point to the existence of marked alterations of NK cells in AML patients, possibly reflecting a host-tumor immunological interaction.

Acute Disease↗
PubMed1993

[Wallstent prosthesis, urethral stenosis, and prostatic nodular hyperplasia. Presentation of our experience].

The present paper reviews our experience in the use of Wallstent prosthesis. We contribute a total of seven patients which presented with bulbar urethra stenosis (five cases) and benign prostate hyperplasia (two cases), all of which had undergone periodical dilation prior to the prosthesis implant as well as various endoscopic urethrotomies. Here, we report the indications, exclusion criteria, criteria for evaluation of results, and brief description of the technique or method used for the prosthesis implant. Finally, we report on the procedure's advantages and the need to conduct extensive studies (prospective and randomized) in order to clarify the place such prosthesis may take within the therapeutic field of stenosis of the urethra, and in benign prostate hyperplasia.

Aged↗
PubMed1992

Endometrial stromal sarcoma expression of estrogen receptors, progesterone receptors and estrogen-induced srp27 (24K) suggests hormone responsiveness.

The endometrial stroma plays a decisive role in sustaining the gland epithelium along the menstrual cycle, and in preparing the microenvironment that allows embryo implantation. The stroma undergoes important changes during the menstrual cycle that affects both the cell number and differentiation. These changes are regulated by both estrogen and progesterone. Stromal sarcomas are extremely rare, occurring much less than any other uterine tumor. Their origin and biology are poorly understood. The purpose of this work was to try to learn more about the stromal physiology, and also to ascertain whether the stromal sarcoma has characteristics of hormone dependence. We studied the presence of estrogen receptors (ER), progesterone receptors (PR) and the stress-responsive protein of 27K (srp27, a protein first described as an estrogen-induced 24K protein in MCF-7 cells) in both normal stroma and stromal sarcoma. The ER and PR were measured by exchange assays. The srp 27 was studied both by Western-blot and by IHC by means of specific monoclonal antibodies. The stromal sarcomas studied showed a high concentration of both ER (96 to 116 fmol/mg prot.) and PR (565 to 995 fmol/mg prot.). These amounts of ER and PR were higher than the mean found in normal endometrium during the proliferative phase (43 and 637 fmol/mg prot., respectively), and much higher than that of the secretory phase (17 and 229 fmol/mg prot., respectively). The srp27 characterized by Western-blot in both the normal stroma and stromal sarcoma was found to be similar to the srp27 of breast cancer. The IHC results showed a very low expression of srp27 in the stroma during the proliferative phase that increases when the endometrium enters the secretory phase. The low-malignancy grade stromal sarcomas showed abundant expression of srp27, but the high-malignancy grade sarcomas showed no expression of srp27. The obtained results prove the stroma capability to express the srp27. A negative correlation between malignancy of stromal tumors and srp27 expression was found. The presence of ER and PR in some stromal sarcomas proves that they have characteristics of hormone responsiveness. These findings suggest that ER and PR assays should be routinely performed in stromal sarcomas as well as in endometrial adenocarcinomas, and also that antiestrogenic drugs might be considered for the treatment of ER and PR positive stromal sarcomas.

Antineoplastic Agents↗
PubMed1992

The estradiol induction of the microsomal low-affinity glucocorticoid binding sites (LAGS) in the male rat liver is independent of the endocrine status.

The low-affinity glucocorticoid binding sites (LAGS) are entities present in the microsomal fraction of the rat liver, capable of binding several glucocorticoids and progesterone with low affinity. The present work focuses on the demonstration that estradiol exerts a powerful stimulatory effect on the LAGS concentration. For this purpose, we studied the effect of this hormone in immature, hypothyroid, and hypophysectomized rats, three experimental models which present a very low level of LAGS. In all of them, estradiol showed ability to significantly increase the level of LAGS. The positive results obtained in hypophysectomized rats point to a direct action of estradiol on the liver. In immature rats, the estradiol induction of the LAGS was shown to be especially slow, 3-4 days after estradiol administration being necessary to obtain a significant rise in the level of LAGS. Moreover, the dose of estradiol necessary to obtain the LAGS induction in these rats (0.5 mg/100 g body weight) was clearly supraphysiological. From these data we concluded that: (A) estradiol is a powerful stimulator of the LAGS concentration, its effect probably being exerted directly on the liver; and (B) to elicit its effect, estradiol does not need the participation of other hormones known to be implicated in the endocrine regulation of the LAGS.

Animals↗
PubMed1992

The development of category-based induction.

In a category-based induction, knowing that a property is true of some category members leads one to conclude that the property is true of other category members. An example is: Cardinals have ulnar arteries. Therefore hawks have ulnar arteries. Recently, Osherson et al. (1990) demonstrated a number of phenomena involving category-based inductions, and proposed that these phenomena can be explained by variations in 2 processes: (a) the similarity between the premise category (cardinals in the above example) and the conclusion category (hawks in the above example), and (b) the degree to which the premise category "covers" (roughly, is similar to) instances of the lowest-level category that includes both the premise and conclusion categories (birds in the above example). The present paper traces the developmental course of the relevant phenomena and of the similarity and coverage processes that presumably underlie them. Studies 1 and 2 demonstrated that the inductions made by kindergartners are sensitive only to the similarity between the premise and conclusion categories. Studies 3 and 4 showed that second graders' inductions are sensitive to both premise-conclusion similarity and coverage, as long as there is no need actually to use a generated category that includes both the premise and conclusion categories. These developmental findings reveal an orderly process in the growth of category-based inductions, and also decompose the Osherson et al. model into 3 basic components that have not previously been explicitly distinguished.

Animal Population Groups↗
PubMed1992

[Evaluation of nuclear roundness as a tool for prostatic carcinoma grading].

The microscopic patterns adopted by prostate carcinomas are extraordinarily variable making its histopathological classification and grading extremely complicated. There are numerous systems for prostatic tumours' grading, but many of them lack a truly reproducible character and an acceptable degree of reliability; for this reason, we have studied a series of nuclear microscopic parameters, from a quantitative point of view, in a series of prostatic carcinomas with a minimum follow-up of five years. It was observed that of the morphometric values obtained--area, perimeter, projection on the X- and Y-axis as well as the nuclear roundness factor--the most useful and representative is the latter. Besides, this is an objective parameter to evaluate nuclear anaplasia and can also be considered as a prognostic factor since, in our series, those who died had a greater mean nuclear roundness factor than those who survived.

Aged↗
PubMed1992

[Embryonal development of interstitial Leydig cells in the rat testis].

Blood testosterone concentrations are not constant throughout life, there being a direct correlation with the numbers of cells producing that hormone, for which reason the existence of two Leydig's cells populations has been proposed: one foetal formation, which disappears just prior or immediately after birth, and a subsequent adult generation. In recent studies, however, that withdrawal has not been observed. Considering all the above, we have studied the evolution of these elements during the rat foetal period. From a morphological point of view Leydig's cells do not differentiate from those in the gonadal interstice until day 17 of pregnancy, showing a considerable increase in their numbers by day 21: while from that day onwards their numbers decrease they never disappear completely. We believe those cells become differentiated from the interstitial mesenchymal cells, and that their increase is facilitated by the proliferation of these same elements.

Animals↗
PubMed1992

[The nuclear roundness factor as a parameter in the anatomoclinical correlation of prostatic carcinoma].

This paper correlates the nuclear roundness factor to clinical stage, patient's age and acid phosphatase level at the time of diagnosis in a group of 48 patients with prostate carcinoma and a minimal follow-up of 5 years. It has been demonstrated that, from an anatomo-clinical point of view, the nuclear roundness factor is a good indicator because it presents increasing values as the clinical stage of tumoral extension worsens, and in those stages where the number of patients was relatively high the average of deaths was always higher than that of survivors. On the other hand, a direct correlation to total acid phosphatase, and an inverse correlation to age at the time of diagnosis was shown in patients with changes in these values.

Age Factors↗
PubMed1991

Effects of dihydropyridines and inorganic calcium blockers on aggregation and on intracellular free calcium in platelets.

[Ca2+]i increase is necessary in physiological platelet activity, particularly aggregation and release. The increase of [Ca2+]i observed during platelet activation depends in part on Ca2+ influx from the extracellular medium. The participation of voltage-operated Ca2+ channels as a pathway for Ca2+ entry is controversial. In the present study we have attempted to reinvestigate this problem by measuring aggregation and [Ca2+]i changes in platelets activated by ADP or thrombin and incubated with organic or inorganic blockers of calcium channels. The main findings of the present paper can be summarized as follows: (i) Ni2+, Co2+ and Mn2+, well known inorganic blockers of Ca2+ channels, inhibited platelet aggregation induced by ADP or thrombin in a dose-dependent manner, Ni2+ being the most effective agent. (ii) Thrombin induced a rise in free [Ca2+]i in platelets incubated both in 1 mmol/l Ca(2+)-containing medium and in nominally Ca(2+)-free medium; the rise of free [Ca2+]i was in the first case up to 370 +/- 31 nmol/l and in the second case up to 242 +/- 26 nmol/l, indicating that this observed difference was due to Ca2+ entry from the extracellular medium. Co2+ and Ni2+ abolished that difference by inhibiting Ca2+ influx. (iii) Nisoldipine, nitrendipine and nimodipine (10-50 nmol/l) inhibited in a dose-dependent manner platelet aggregation induced by either ADP or thrombin in platelets incubated in normal-Ca2+ normal-K+ medium, also, aggregation was inhibited to a similar extent in platelets incubated in normal-Ca2+ high-K+ medium. (iv) Nisoldipine--the most effective dihydropyridine to inhibit platelet aggregation--also inhibited Ca2+ influx in platelets incubated in normal-Ca2+ medium, either in normal-K+ or high-K+ media. Our data support the existence of voltage-operated, dihydropyridine-sensitive calcium channels (L-type) and a physiological role for them in platelet function.

Adenosine Diphosphate↗