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Biomedical subjects

N Andrade

Publications and source records attributed to N Andrade.

10 recordsLinked to original sources
PubMed1999

Factor structure of the CES-D (Center for Epidemiologic Studies Depression Scale) among Filipino-American adolescents.

The present study used factor analytic procedures to examine the factor structure of the CES-D among Filipino-American adolescents residing in rural and small town Hawaii. A total of 243 Filipino-American high school students completed the 20-item scale, and maximum likelihood analyses were employed to obtain a final solution. The results indicated that two factors provide a reasonably good fit: factor I combined depressed affect, somatic-retardation and interpersonal items, and factor II consisted of the remaining four positive affect items. The overlap of depressed affect and somatic symptoms support previous findings found among Asian American adults and other ethnic minority adolescents. The loading of the interpersonal items on the first factor is more unusual and suggests that interpersonal factors are not distinguished from depressed affect for the Filipino-American adolescent group. The usefulness of the CES-D as a tool to gain an understanding of the concept of depression across cultures is discussed.

Adolescent↗
PubMed1997

Hormone dependence of mammary tumors induced in rats by intraperitoneal NMU injection.

The purpose of this work was to determine the hormone dependence of mammary tumors induced in Sprague-Dawley rats by three intraperitoneal injections of N-nitroso-N-methylurea at 50, 80, and 110 days of age. Two experimental designs were carried out: (a) Ten days before the first NMU injection, 130 rats were divided into 13 batches and randomly assigned to the following treatments: control, ovariectomy (OVX), tamoxifen (TAM), bromocriptine (BROM), haloperidol (HAL), estradiol (E2), progesterone (Pg), OVX + BROM, TAM + BROM, OVX + HAL, TAM + HAL, OVX + TAM, and E2 + BROM. After 150 days of treatment the following growth parameters were determined: latency period (LP), mean tumor number per rat (n/t), and tumor incidence (TI). LP was significantly increased (p < 0.05) only by Pg and TAM + BROM. The n/t was significantly decreased (p < 0.05) by all treatments except HAL. TI was significantly reduced by OVX, TAM, BROM, and their combinations, (b) Rats bearing ip-NMU-induced mammary tumors were divided into 7 batches and assigned to the following treatments: control, OVX, TAM, BROM, HAL, OVX + BROM, and TAM + BROM. Tumor growth was assessed up to 60 days of treatment; only OVX, TAM and their combination with BROM were able to produce tumor regression. These results support the essential role of E2 and prolactin in the promotion stage of carcinogenesis. However, for established tumors, growth becomes more independent from hormone influence, in particular from prolactin deprivation. We conclude that this model seems suitable for studying the mechanisms underlying the evasion of hormonal control of tumor growth.

Animals↗
PubMed1996

Receptors characterization of intraperitoneally N-nitroso-N-methylurea-induced mammary tumors in rats.

Mammary adenocarcinomas induces in female Sprague-Dawley rats by three intraperitoneal injections of N-nitroso-N-methylurea were studied in order to characterize their estrogen (ER), progesterone (PgR), prolactin (PRLR) and epidermal growth factor (EGFR) receptors. All samples evaluated showed the presence of ER and PgR in the cytosol fraction and PRLR amd EGFR in the membrane fraction. Q (fmol/mg) and K(d) (nM) values were as follows: ER, 56 +/- 11 and 0.5 +/- 0.1; PgR, 109 +/- 25 and 2.2 +/- 0.5 and PRLR, 335 +/- 75 and 0.5 +/- 0.2, respectively. In all tumors studied, two specific sites were found for EGFR, one with Q(1) = 22 +/- 9 and K(d1) = 0.6 +/- 0.3, and the other with Q(2) = 125 +/- 33 and K(d2) = 2.1 +/- 0.5. Receptor content was found to be independent of tumor histopathological variety. Displacement index (DI) with estradiol and tamoxifen of [I(3)H]E2-ER binding showed great heterogeneity, with values ranging from 0.01 to1.54. No correlation between ER content and DI values was found. Antiestrogenic binding sites were not found in the microsomal fraction of ten mammary tumors examined. Proliferation of this experimental mammary tumor may be regulated by a complex interaction of steroid and polypeptide hormones, as well as growth factors.

Animals↗
PubMed1996

Effect of tamoxifen on intraperitoneal N-nitroso-N-methylurea induced tumors.

The effect of tamoxifen (TAM) was evaluated on a mammary tumor model induced in Sprague-Dawley rats by intraperitoneal administration of three N-nitroso-N-methylurea (NMU) doses. Animals received TAM (1 mg/kg per day) from 10 days before the first NMU dose up to 140 days later. Thereafter, treatment was discontinued and the observation period was extended 60 days longer. Mean overall latency period, tumor number per rat and tumor incidence were recorded. Significant differences between treated and control batches were observed in tumor number per rat (1.8 +/- 1.1 versus 5.2 +/- 1.6; P < 0.05) and in tumor incidence (50% versus 100%; P < 0.05), respectively. No significant difference in latency period between both batches was recorded. All lesions induced in the control batch were malignant, whereas only 45% of those induced in TAM-treated animals were malignant and the remaining 55% were preneoplastic. At 60 days after treatment discontinuance, tumor incidence increased to 90% and also tumor number per rat increased to 4.6 +/- 1.5. TAM effect was also evaluated in rats with NMU-induced tumors by treatment with 1 mg/kg per day during 60 days starting when tumors reached a 1.5-cm diameter. Regression to less than 80% of initial size in 49% of the tumors was observed, while in ovariectomized rats, 33% of tumors regressed. Estrogen receptor content, ER (fmol/mg protein) and Kd (nM) in control tumors were: 56 +/- 10 and 0.5 +/- 0.1. In tumors of TAM-treated animals, ER was less than 5 fmol/mg protein. Findings demonstrate that TAM significantly decreased the appearance of tumors induced in rats by i.p. injection of NMU and when TAM treatment was initiated after tumor induction, some tumors failed to respond to hormonal manipulation. Differential tumor growth response after TAM or oophorectomy in each tumor indicates that in the same rat it is possible to distinguish hormone-dependent and hormone-autonomous tumor populations. Hormonal regulation of tumor growth can be under intrinsic control, regardless of the hormonal status of the whole organism.

Animals↗
PubMed1996

What are the limits for the Ross operation?

The Ross operation is physiologically the best approach for aortic valve replacement. At the Hospital de Santa Cruz 22 consecutive pulmonary autograft operations have been performed in patients with a mean age of 49 (range 17-65) years. Six patients had mitral valve disease, two had aortic aneurysms and one had a ventricular septal defect. Subcoronary implantation of the autograft was performed in 20 patients. A partial inclusion aortic root replacement technique was used in one and the aortic root was replaced in another. There were no hospital or late deaths. Two patients required autograft replacement at 3 and 9 months postoperatively because of regurgitation. One of these cases was caused by an abnormality of the pulmonary valve and since then echocardiographic assessments of this valve have been performed routinely and have detected significant pulmonary incompetence in four patients who otherwise would have been operated on using the Ross procedure.

Adolescent↗
PubMed1996

The rate and characteristics of suicide attempters in the native Hawaiian adolescent population.

Native Hawaiian high school students, N = 1779, were surveyed for symptoms of psychopathology and suicide attempts in the previous 6 months. Seventy-seven (4.3%) of the students reported making a suicide attempt. There were no significant differences in prevalence rates for males and females. Depression, anxiety, aggression, substance abuse symptoms, and low family support, but not peer support, were significantly correlated with suicide attempts. On logistic regression, depression, substance abuse, and family support independently predicted attempts. The lack of gender difference may indicate a cultural characteristic of the Hawaiian population that differentiates it from mainstream American populations but likens it to the Native American population.

Adolescent↗
PubMed1994

Induction of mammary tumors in rat by intraperitoneal injection of NMU: histopathology and estral cycle influence.

In order to obtain an experimental model we induced mammary tumors in female Sprague-Dawley rats. The carcinogen N-nitroso-N-methylurea (NMU) was injected intraperitoneally (i.p.) at doses of 50 mg/kg body weight when animals were 50, 80 and 110 days old. Tumor sizes were measured with a caliper and their growth parameters and histopathological properties were tested. For 100 rats, 88.4% of developed lesions were ductal carcinomas, histologically classified as 52.8% cribiform variety, 30.6% solid carcinoma. Metastases in liver, spleen and lung were present. Other primary tumors were detected with low incidence. The influence of the rat estrous cycle during the first exposure to intraperitoneal NMU injection was studied. The latency period in estrus, proestrus and diestrus was 82 +/- 15, 77 +/- 18 and 79 +/- 18 days, respectively. Tumor incidence was significantly higher in estrus (95.2%) than proestrus (71.4%) or diestrus (77.4), (P < 0.01). Mean number or tumors per animal was similar among the three groups (4.4 +/- 3.2, 3.8 +/- 3.6, 3.2 +/- 1.8). The procedure described appears to be the simplest method for inducing experimental mammary tumors in rats.

Animals↗