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Biomedical subjects

L Ramos

Publications and source records attributed to L Ramos.

At least 73 records · Page 4Linked to original sources
PubMed1998

Problems associated with hazardous and harmful alcohol consumption in Mexico.

This chapter presents research findings from a collaborative project between Mexican investigators from the Mexican Institute of Psychiatry and the World Health Organization on the identification and treatment of harmful and hazardous drinking. A sample of 189 individuals who met criteria for hazardous drinking was selected for the study after screening 2319 outpatients attending clinics in two general hospitals in Mexico City. We present here the characteristics of this sample along dimensions that include alcohol related problems, history of trauma, alcohol dependence scores and family history of alcoholism. We rated, utilizing structures interviews, situations that place these individuals at risk of drinking. The possibility of constructing a typology of harmful and hazardous drinking was also explored. The significance of the findings of this investigation for health care clinicians is discussed.

Adolescent↗
PubMed1998

Surgical sperm retrieval and intracytoplasmic sperm injection as treatment of obstructive azoospermia.

Male genital tract obstructions may result from infections, previous inguinal and scrotal surgery (vasectomy) and congenital bilateral absence of the vas deferens (CBAVD). Microsurgery can sometimes be successful in treating the obstruction. In other cases and in cases of failed surgical intervention, the patient can be treated by microsurgical or percutaneous epididymal sperm aspiration (MESA, PESA) or testicular sperm extraction (TESE) and intracytoplasmic sperm injection (ICSI). We present the results of 39 ICSI procedures for obstructive azoospermia in 24 couples. The aetiology of the obstruction was failed microsurgery in 11 patients, CBAVD in nine and genital infections in four. Sperm retrieval was accomplished via MESA in four cases, PESA in 18 cases and via TESE in 11 cases. TESE was only applied when PESA failed to produce enough spermatozoa for simultaneous ICSI. In six patients, the ICSI procedure was performed with cryopreserved spermatozoa after an initial PESA procedure. Fertilization occurred in 47% of the metaphase II oocytes; embryo transfer was performed in 92% of procedures and resulted in a clinical pregnancy in 13/39 procedures. Ongoing pregnancy was achieved in 10/39 procedures. One pregnancy was terminated early after prenatal investigation showed a cytogenetic abnormality (47,XX+18, Edwards syndrome). The other nine pregnancies resulted in the live birth of 10 children, without any congenital abnormalities. Epididymal and testicular retrieved spermatozoa were successfully used for ICSI to treat obstructive azoospermia, and resulted in an ongoing pregnancy in 10 of 24 couples (41.6%) after 39 ICSI procedures, a success rate of 25.6% per treatment cycle and of 27.7% per embryo transfer.

Embryo Transfer↗
PubMed1997

Differential subcellular localization, expression and biological toxicity of BRCA1 and the splice variant BRCA1-delta11b.

The mechanism of BRCA1 tumor suppression in human breast and ovarian cells is the focus of intense investigation. In this report, full length BRCA1 (230 kDa) introduced into cells with CMV promoter constructs was nuclear when transgene expression was low whereas high expression resulted in cytoplasmic accumulation, aberrant nuclear and cell morphology. A nuclear localization signal (NLS) was mapped to BRCA1 amino acid positions 262-570. We describe a splice variant, BRCA1-delta11b, missing the majority of exon 11 including the NLS. Exogenous BRCA1-delta11b (110 kDa) was cytoplasmic and, unlike the full-length protein, overexpression of the protein encoded by the variant did not appear to be toxic. RNA probe titrations and RT-PCR demonstrated that BRCA1 and delta11b transcripts are coexpressed in a wide variety of cells and tissues. Interestingly, BRCA1-delta11b message was greatly reduced or absent in several breast and ovarian tumor lines relative to exon 11 transcripts and a delta9,10 splice variant. Taken together our results suggest that full-length BRCA1 and BRCA1-delta11b may have distinct roles in cell growth regulation and tumorigenesis.

Alternative Splicing↗
PubMed1997

Variation of PCB congener levels during lactation period and relationship to their molecular structure.

The levels of 22 polychlorinated biphenyl (PCB) congeners, including 13 coplanars (non-, mono-, and di-ortho-substituted chlorine) and 9 noncoplanar chirals (tri- and tetra-ortho-substituted chlorine), were measured in mothers milk from different mothers throughout their lactation periods. Important variations were found in the total PCB levels and PCB congener levels. The maximum PCB variations were found during the first weeks of lactation. Of the 22 PCBs analyzed, the most abundant, and those which had the highest variations were PCB-101, 118, 138, 151, 170, and 180, while the least abundant were the PCB-77, 126, 169, and 167, which also showed the lowest variation. Among the nonortho-substituted PCB congeners, PCB-77 was the predominant PCB in three of the four lactation periods studied, while PCB-126 was dominant in the last case. A relationship has been found between the levels and variations of total PCBs in the milk supplied by the different mothers and their dietary habits, weight changes and illness suffered during their pregnancy and lactation. The 22 PCB congeners investigated have been grouped in five categories according to their concentration variations in milk throughout the four different lactation periods. The PCB congeners included in each of the five groups have similar molecular structures. It has been found that coplanarity, number of chlorines and their molecular distribution, and neighbor H atoms were determinant factors in the process of PCB mobilization from the mothers' fats (where it had been able to accumulate throughout her life in the case of her first child) to the breast milk she delivered.

Adult↗
PubMed1997

Levels of PCDDs and PCDFs in farm cow's milk located near potential contaminant sources in Asturias (Spain). Comparison with levels found in control, rural farms and commercial pasteurized cow's milks.

Cows milk samples from 12 dairy farms in Spain and 23 samples of pasteurised cows milk were analysed for PCDD/F. Farms located in rural areas without specific dioxin sources (background levels) ranged from 1.3 to 2.47 pg TEQ/g fat basis. These values were slightly lower than those found in milk from the vicinity of potential dioxin emission sources (waste incinerator, chemical and metallurgical industry) and similar to milk near paper industry. The waste incinerator seems to be the emission source with the highest influence on the cows milk gathered in its vicinity. Thus, milk near the waste incinerator exhibited the highest PCDD/F levels, the highest PCDF/PCDD ratio and its congener PCDD pattern showed the highest difference respect to its control point. The PCDD/F average concentrations found in pasteurised commercial milk were lower than those found in raw milk and were comparable to those found in retail milk from other countries.

Animals↗
PubMed1997

Inflammatory myofibroblastic tumor of bone: report of two cases with evidence of clonal chromosomal changes.

Inflammatory myofibroblastic tumor (inflammatory pseudotumor) is a pseudosarcomatous lesion that is recognized with increasing frequency in various anatomic locations. However, this lesion has not been previously reported in bone. We report on two cases of inflammatory myofibroblastic tumor occurring in bone in young adults. Both tumors presented as slightly painful, osteolytic, and well-delineated lesions of the distal femur, with a hyperintense signal on T2-weighted magnetic resonance imaging. The patients had an uneventful recovery after curettage. The follow-up time was 11 months for both patients, and no recurrence was noted. On histologic examination, the lesions were characterized by collagen-rich and generally poorly cellular tissue containing spindled to plump (myo)fibroblast-like cells and a variable admixture of inflammatory cells. Focal calcifications and reactive bone formation were present. Clonal, albeit different, chromosomal changes were found in both cases (47,XY,-9,-12,add(21)(q21),+der(?)t(?;9)(?;q11), +mar,+r and 47, XY, +r/47, idem, add(12)(p13)). The present and other reported cytogenetic findings suggest that inflammatory myofibroblastic tumors could well be neoplastic.

Adult↗
PubMed1997

Smoking cessation with a 16 h nicotine patch: results in a group of hospital workers.

As part of a programme for the implementation of a Smoking Control Policy in our hospital, an open study, without randomization, of 65 hospital workers, who wanted to give up smoking, was carried out. The characteristics of smoking in each subject were recorded. The Fagerstrom Questionnaire was used to measure the degree of dependence on nicotine. The treatment consisted of the daily use of 16 h nicotine patches for 12 weeks. During the first 4 weeks, the patches contained 15 mg of nicotine, for the second 4 weeks, 10 mg, and for the last 4 weeks 5 mg (per patch and day). Five visits were scheduled during the 26 week study period: at the start of the study and after 4, 8, 12 and 26 weeks. The abstinence was checked by measuring carbon monoxide in end-expiratory air. The success rate was 31% after 12 weeks, and decreased to 29% after 26 weeks. In conclusion, the nicotine patches appeared safe and effective in this study.

Administration, Cutaneous↗
PubMed1996

Gallbladder dyskinesia in acalculous biliary colic.

AIMS: To test the hypotheses that: 1) postprandial gallbladder emptying might be abnormal in patients with acalculous biliary colic; and 2) that hymecromone, a drug that increases bile flow and relaxes biliary muscle might improve symptoms. METHODS: Twenty-four women were studied. Twelve patients presented recurrent biliary type of pain in the absence of gallstones, and persistence of contrast in the gallbladder, 24 hours after an oral cholecystogram, suggesting cholesterolosis. Twelve healthy volunteers used as controls had no symptoms and the gallbladder was not visible the day after an oral cholecystogram. Gallbladder emptying induced by an oral meal was studied with ultrasound in both groups before and after the administration of hymecromone. RESULTS: Gallbladder volumes were similar in both groups (23 +/- 10 ml vs. 31 +/- 11 ml; NS). Gallbladder emptying in the control group was simple exponential (R2 = 0.948 +/- 0.059) with a rate of 32 +/- 16 minutes. Gallbladder emptying was bimodal in patients. Gallbladder volume increased to 120% in the first 10 minutes, to empty exponentially thereafter (R2 = 0.964 +/- 0.040. Rate: 29 +/- 22 minutes). This resulted in a marked reduction in gallbladder volume emptied at 40 minutes when compared to controls (30% +/- 27% vs. 54% +/- 14%; p = 0.012). Pretreatment of controls with hymecromone induced an emptying pattern similar to that of patients. In patients, emptying after hymecromone did not change but symptoms were improved. CONCLUSIONS: An abnormal emptying pattern of the gallbladder was identified in patients with acalculous biliary colic, and hymecromone was partly effective to reduce pain, despite a minor effect on gallbladder emptying pattern.

Biliary Tract Diseases↗
PubMed1995

HER-2 tyrosine kinase pathway targets estrogen receptor and promotes hormone-independent growth in human breast cancer cells.

Growth of human breast cells is closely regulated by steroid hormone as well as peptide hormone receptors. Members of both receptor classes are important prognostic factors in human breast cancer. Clinical data indicate that overexpression of the HER-2 gene is associated with an estrogen receptor-negative phenotype. In this study, we demonstrate that introduction of a HER-2 cDNA, converting non-overexpressing breast cancer cells to those which overexpress this receptor, results in development of estrogen-independent growth which is insensitive to both estrogen and the antiestrogen, tamoxifen. Moreover, activation of the HER-2 receptor in breast cancer cells by the peptide growth factor, heregulin, leads to direct and rapid phosphorylation of ER on tyrosine residues. This is followed by interaction between ER and the estrogen-response elements in the nucleus and production of an estrogen-induced protein, progesterone receptor. In addition, overexpression of HER-2 receptor in estrogen-dependent tumor cells promotes ligand-independent down-regulation of ER and a delayed autoregulatory suppression of ER transcripts. These data demonstrate a direct link between these two receptor pathways and suggest one mechanism for development of endocrine resistance in human breast cancers.

Animals↗
PubMed1995

HER-2/neu, p53, and DNA analyses as prognosticators for survival in endometrial carcinoma.

OBJECTIVE: To compare the prognostic importance of certain molecular biologic characteristics (HER-2/neu and p53 gene overexpression, DNA ploidy, and the S-phase fraction) to standard clinical-pathologic factors used to predict survival in patients with endometrial carcinoma. METHODS: We reviewed archival specimens from 128 patients with endometrial cancer diagnosed during the period 1985-1987. One hundred four cases were eligible for inclusion in the study. Immunohistochemistry was used to detect p53 and HER-2/neu overexpression. We used flow cytometry to calculate DNA ploidy and the S-phase fraction. Life-table analysis and Cox multiple regression were used to analyze clinical and molecular data with respect to survival. RESULTS: International Federation of Obstetrics and Gynecology stage, nuclear grade, lymph-vascular space invasion, and adverse histopathologic features each significantly correlated with poor outcome (each at P < or = .001). Overexpression of p53 was demonstrated in 15% of the tumors and was associated with a 12% probability of 5-year survival, compared to a 90% probability of 5-year survival for the p53-negative cohort (P = .0001). Thirty percent of the tumors were aneuploid, which was also associated with poor prognosis (P = .0003). HER-2/neu overexpression and an S-phase fraction greater than 10% showed similar trends, but were not statistically significant. On multivariate analysis, p53 overexpression was the strongest independent prognosticator of survival (P = .0001). CONCLUSION: Molecular characteristics provide objective data that may be useful in predicting prognosis in patients with endometrial cancer. Further investigation of molecular and genetic characteristics are needed to refine our diagnostic and treatment modalities.

Aged↗
PubMed1995

Traumatic dislocation of the tibialis posterior tendon: a new surgical procedure to obtain a strong reconstruction.

Traumatic dislocation of the tibialis posterior tendon (TPT) is an uncommon condition. The diagnosis is difficult and may be delayed, impairing the activity level. The authors present a case, wherein the diagnosis was clinical, supported by magnetic resonance imaging. Treatment was surgical; reconstruction of the retinaculum was performed with a medial slip of the Achilles tendon that was detached proximally and attached to the medial malleolus. A full functional recovery to a highly competitive activity was obtained after 12 weeks.

Adult↗
PubMed1995

Differential involvement of protein kinase C in the regulation of transforming growth factor-beta (TGF-beta) secretion by porcine theca and granulosa cells in vitro.

Transforming growth factor-beta (TGF-beta) has been implicated in the regulation of ovarian follicle development. Little, however, is known regarding the regulation of TGF-beta expression within the follicle. To investigate this, granulosa and theca cells were isolated from small antral follicles of prepubertal porcine ovaries, maintained in monolayer culture, and treated with gonadotropins or intracellular activators of the protein kinase A and C pathways. TGF-beta secreted into the medium was measured using a proliferation inhibition bioassay with MvLu1 epithelial cells. Over a broad dose range, FSH and LH were ineffective in stimulating TGF-beta secretion relative to controls in granulosa and theca cells, respectively. Additionally, 8-bromo-cAMP, a direct activator of protein kinase A, was ineffective in stimulating TGF-beta secretion in either cell type. In marked contrast, PMA, a stimulator of protein kinase C, dose-dependently stimulated TGF-beta secretion in theca cells. Interestingly, however, PMA had virtually no effect upon granulosa cells. The stimulatory effect of PMA on theca cell TGF-beta secretion was not observed with the inactive derivitive 4 alpha-PMA, and the PMA effect was inhibited by chelerythrine chloride, an inhibitor with high specificity toward protein kinase C. Taken together, these results argue against a direct role of the protein kinase A pathway in the regulation of TGF-beta expression in porcine follicle cells and support direct involvement of the protein kinase C pathway. Moreover, there appears to be marked differences in the regulation of this growth factor between theca and granulosa cells.

Alkaloids↗
PubMed1994

A large, pigmented nail bed lesion in a child.

An unusual case of an extremely large junctional nevus of the nail bed with histological atypia in a 6-year-old Japanese child is described. The evaluation and management of subungual pigmented lesions is reviewed.

Child↗
PubMed1994

[The nicotine patch. Short-term results in a group of hospital workers].

As part of a not smoking sensibilization programme, focused on the staff of our hospital, we carried out a no randomized following open study over 51 smoker workers. The tobacco withdrawal was achieved in 27.4% of cases after the treatment with nicotine sticking plaster of 16 hours of liberation during a 12 weeks period. Slight and none important adverse reactions were observed. The nicotine sticking plaster shows its usefulness for decreasing the intensity of the withdrawal syndrome on these people.

Administration, Cutaneous↗