Search PubMed⌕ Search

Biomedical subjects

J Quintero

Publications and source records attributed to J Quintero.

18 recordsLinked to original sources
PubMed2001

[Prevalence of risk for mental disorders among undergraduate medical students at the Medical School of the Catholic University of Chile].

BACKGROUND: Stress caused by the high physical, intellectual and emotional demands imposed to medical students, renders them specially susceptible to the development of mental disorders. AIM: To assess the prevalence of risk for mental disorders among undergraduate students at the Medical School of the Catholic University of Chile. MATERIAL AND METHODS: The Twelve Item General Health Questionnaire (GHQ 12) was voluntarily answered by medical students from the first to the fifth year. RESULTS: Sixty eight percent of the total population (305 students) answered the questionnaire. Forty one percent of students were at risk, defined as scoring five or more points in the GHQ 12. The average score was 3.9 +/- 2.2. First year students had a higher score than fourth year students (4.6 +/- 2.2 and 3.4 +/- 2.1 points respectively, p < 0.05). No gender differences were observed. CONCLUSIONS: Our results are similar to those of other publications concerning psychiatric risk among medical students.

Adolescent↗
PubMed2001

[Effect of oral and intramuscular vitamin K on the factors II, VII, IX, X, and PIVKA II in the infant newborn under 60 days of age].

BACKGROUND: Neonates on exclusive breast feeding that do not receive vitamin K at birth are at higher risk hemorrhagic disease of the newborn. AIM: To compare the effect of oral or intramuscular administration of vitamin K1 (VK1), on clotting factors II, VII, IX, X and PIVKA II, in children until the 60 days of age with exclusive breast feeding or mixed feeding. PATIENTS AND METHODS: Forty healthy full term infants, distributed in two groups, A: 20 with mixed feeding (formula-feeding and breast-feeding) and B: 20 with exclusive breast feeding, were studied. Nine infants of each group received 1 mg of VK1 intramuscularly and eleven 2 mg VK orally 5 ml of cord blood was collected initially from each infant. Venous blood samples were taken on 15, 30 and 60 days of age. RESULTS: All factors increased in a progressive form reaching levels over 50% at 60 days of age, in both groups. PIVKA II decreased significantly during the study period (p < 0.01). Factor II increased more in children with mixed feeding that received intramuscular vitamin K, than in the rest of study groups. No other differences between groups were observed. No infant had an abnormal bleeding during the study period. CONCLUSIONS: Oral administration of vitamin K is as effective as the intramuscular route in the prevention of the hemorrhagic disease of the newborn.

Administration, Oral↗
PubMed2000

Optimization of a weak 3' splice site counteracts the function of a bovine papillomavirus type 1 exonic splicing suppressor in vitro and in vivo.

Alternative splicing is a critical component of the early to late switch in papillomavirus gene expression. In bovine papillomavirus type 1 (BPV-1), a switch in 3' splice site utilization from an early 3' splice site at nucleotide (nt) 3225 to a late-specific 3' splice site at nt 3605 is essential for expression of the major capsid (L1) mRNA. Three viral splicing elements have recently been identified between the two alternative 3' splice sites and have been shown to play an important role in this regulation. A bipartite element lies approximately 30 nt downstream of the nt 3225 3' splice site and consists of an exonic splicing enhancer (ESE), SE1, followed immediately by a pyrimidine-rich exonic splicing suppressor (ESS). A second ESE (SE2) is located approximately 125 nt downstream of the ESS. We have previously demonstrated that the ESS inhibits use of the suboptimal nt 3225 3' splice site in vitro through binding of cellular splicing factors. However, these in vitro studies did not address the role of the ESS in the regulation of alternative splicing. In the present study, we have analyzed the role of the ESS in the alternative splicing of a BPV-1 late pre-mRNA in vivo. Mutation or deletion of just the ESS did not significantly change the normal splicing pattern where the nt 3225 3' splice site is already used predominantly. However, a pre-mRNA containing mutations in SE2 is spliced predominantly using the nt 3605 3' splice site. In this context, mutation of the ESS restored preferential use of the nt 3225 3' splice site, indicating that the ESS also functions as a splicing suppressor in vivo. Moreover, optimization of the suboptimal nt 3225 3' splice site counteracted the in vivo function of the ESS and led to preferential selection of the nt 3225 3' splice site even in pre-mRNAs with SE2 mutations. In vitro splicing assays also showed that the ESS is unable to suppress splicing of a pre-mRNA with an optimized nt 3225 3' splice site. These data confirm that the function of the ESS requires a suboptimal upstream 3' splice site. A surprising finding of our study is the observation that SE1 can stimulate both the first and the second steps of splicing.

Alternative Splicing↗
PubMed2000

Atrophic ununited diaphyseal fractures of the humerus with a bony defect: treatment by wave-plate osteosynthesis.

We treated 15 patients with atrophic nonunion of a diaphyseal fracture of the humerus with an associated bony defect using an autogenous cancellous bone graft and a plate to bridge the defect. There were nine men and six women with a mean age of 48 years. The mean length of the bony defect was 3 cm. At a mean follow-up of 30 months only one fracture failed to unite. This suggests that, in the presence of a well-vascularised envelope of muscle, the application of an autogenous cancellous bone graft in conjunction with a bridging plate represents a good alternative to more demanding surgical techniques.

Adult↗
PubMed2000

[Prevalence of the activated protein C resistance in indigenous and Black populations of the western Venezuela].

The Activated Protein C Resistance (APCR) is the common phenotype of Factor V Leiden (arg506gln), which is considered as a thrombotic risk factor. The aim of this study was to determine the prevalence of APCR and its association with Factor V Leiden in indian and black populations from Zulia State in western Venezuela. Blood samples were taken from 80 Yukpa indians from Sierra de Perijá and 91 black individuals from the southeast of Lago de Maracaibo. APCR was determined by the Dahlback's method with the modifications of Jorquera et al. and Trossaert et al. The results were expressed as n-APC-SR (positive value < or = 0.75). Factor V Leiden genotype was identified by PCR and restriction analysis standard methods at the Institute of Human Genetics (Greifswald, Germany). No significative difference was found between n-APC-SR from indians (mean +/- SEM 1.13 +/- 0.02, CI 95% = 1.07-1.19) and black people (1.07 +/- 0.02, CI 95% = 1.03-1.12). APCR prevalence from indians was 1.25% (1 out of 80) who was heterozygote case for F V Leiden and 4.4% (4 out of 91) from blacks (one case was heterozygous for F V Leiden). No thrombotic event personal or familial was demonstrate. Our data represent the first report related to the association between APCR and F V Leiden in venezuelan indian and black individuals. APCR without the Factor V Leiden expression suggest a different type of mutation in the Factor V molecule. In spite of high endogamy in the indian group, we can not discard the role of foreign genes in both populations. The determination of the prevalence of this phenotype and its molecular marker in various ethnic groups is important for the interpretation of their role as risk factors for thrombotic disease.

Activated Protein C Resistance↗
PubMed1998

[Mouth-washing with tranexamic acid in patients treated with oral anticoagulants subjected to oral surgery procedures].

The purpose of the present work was to observe local hemostatic function during dental surgery in patients under oral anticoagulant therapy with an INR between 1.7 and 2.5. Thirty seven dental treatments were performed in 15 patients. Group A: nineteen dental treatments (13 scalings, 1 root canal therapy and 5 dental extractions), treated with oral rinse with tranexamic acid (250 mg dissolved in 10 ml of water). Group B: eighteen dental procedures (13 scaling, 1 root canal therapy and 14 dental extractions), in which oral rinse was utilized. Antibiotics were indicated for those patients with root canal therapy or with signs of infection. A cool soft diet was recommended to all patients during the three days following the surgical procedure. Only in five (13.5%) dental extractions (1 from group A and 4 from B) bleeding prolonged was observed, however periodontal disease was also present in those patients hone of them required blood products or withdrawal of the anticoagulant. The results suggest that mouth washing with tranexamic acid prevents excessive oral bleeding in patients treated with oral anticoagulants with an INR between 1.7 and 2.5.

Anticoagulants↗
PubMed1997

Use of interferon-alpha in laryngeal papillomatosis: eight years of the Cuban national programme.

Laryngeal papillomatosis is one of the first diseases where interferon (IFN) was found to be effective. In 1983, a programme for the treatment of all such cases started in Cuba. Up to December 1991, 125 patients (92 children, 33 adults) have been treated: 102 with leucocyte IFN-alpha, 12 with recombinant IFN-alpha-2b, and 11 have received both preparations. Case management consisted of surgical removal of the lesions followed by an IFN schedule starting with 10(5) IU/kg of weight in children or 6 x 10(6) IU in adults, i.m. daily. The dose was progressively reduced, as long as no relapses occurred. At the end of the one-year schedule the doses were reduced to 5 x 10(4) IU/kg in children or 3 x 10(6) IU in adults, weekly. If there was a relapse, it was removed surgically and the patient returned to a higher dose level. Most cases (89; 71 per cent) have not relapsed after the treatment; 60 of them have been followed for more than three years. In those with relapses, the frequency of recurrence decreased in all but four patients. The treatment seemed to be more effective if initiated less than three months after the disease onset. The tracheostomy could be removed in five out of seven patients who needed it before the IFN treatment and was necessary in only three new cases during IFN treatment. In two of these, decannulation was possible later on. In a total of 14 patients relapses persisted after several cycles of IFN treatment. They were considered resistant to such treatment. No severe side effects were reported. The most frequent ones were fever, drowsiness, increased bronchial secretion, chills and headache. The establishment of this programme has maintained the disease under control in Cuba.

Adolescent↗
PubMed1997

Molecular cloning of a lobster G alpha(q) protein expressed in neurons of olfactory organ and brain.

We have isolated from an American lobster (Homarus americanus) olfactory organ cDNA library a clone, hG alpha(q), with >80% identity to mammalian and arthropod G alpha(q) sequences. In brain and olfactory organ, hG alpha(q) mRNA was expressed predominantly in neurons, including virtually all the neuronal cell body clusters of the brain. G alpha(q) protein was also expressed broadly, appearing on western blots as a single band of 46 kDa in brain, eyestalk, pereiopod, dactyl, tail muscle, olfactory organ, and aesthetasc hairs. These results suggest that hG alpha(q) plays a role in a wide variety of signal transduction events. Its presence in the olfactory aesthetasc hairs, which are almost pure preparations of the outer dendrites of the olfactory receptor neurons, the expression of a single hG alpha(q) mRNA species (6 kb) in the olfactory organ, and the localization of hG alpha(q) mRNA predominantly in the olfactory receptor neurons of the olfactory organ strongly suggest that one function of hG alpha(q) is to mediate olfactory transduction.

Animals↗
PubMed1997

Complex nonunion of fractures of the femoral shaft treated by wave-plate osteosynthesis.

We have treated 42 consecutive complex ununited fractures of the femoral shaft by wave-plate osteosynthesis at five different medical centres. There were 13 with previous infection, 12 with segmental cortical defects, and 3 were pathological fractures. In 39 cases there had been previous internal fixation and 21 patients had had more than one earlier operation. Union was achieved in 41 patients at an average of six months, although three had required a second bone graft. Two patients had recurrence of infection and in one this resulted in the persistence of nonunion. There were no failures of the implant. All 41 patients with union are now fully weight-bearing, but four have a leg-length discrepancy, one has axial malalignment, and nine have residual stiffness of the knee. These results are surprisingly good, despite the complexity of the initial problem, and appear to confirm the biological and mechanical advantages of the wave plate over the conventional plate for such cases.

Adolescent↗
PubMed1996

[Nutritional status and body composition of a group of non-institutionalized elderly in the State of Zulia, Venezuela].

To assess the nutritional status and body composition of an elderly free-living population from the State of Zulia, Venezuela, ninety-four persons (47 male and 47 female), ages ranging from 60 to 88 years (mean age 69.55 +/- 6.60) (X +/- SD) were studied. Anthropometric measurements, and a dietary study by means of 24-hour recall and a Food Frequency were performed. Significant statistical differences (p < 0.001, and p < 0.05) were observed among female and male groups in all measures and indices except weight, waist, arm area, and arm muscle area. Significant differences (p < 0.05) were also observed among age groups in weight, Quetelet index, percentage ideal weight (% IW), and triceps skinfold thickness. The means of anthropometric measures and nutritional indicators were higher than the results obtained in other studies. The percentage of elderly obese with Quetelet greater than 30 kg/m < or = was 42.6% (females) and 6.4% (males). In contrast, when utilizing % IW it was observed that 4.3% of the men and 48.9% of the women were obese. Body fat distribution index (waist/hip) shows abdominal fat distribution in 21.3% males and 68.1% females. We found sex-based significant differences in dietary intake of energy, total fat, carbohydrates, iron, vitamin A, and thiamin. The results indicate that the intake of protein, total fat, calcium, phosphorus, iron, thiamin, and niacin is high among males y females, when compared with the present Recommended Dietary Allowance (RDA) values of Venezuela. The intake of carbohydrate, fiber, vitamin A, riboflavin, zinc, and copper is low among males and females according RDA values, as well as the intake of riboflavin in males. The study indicates a high frequency of men and women obese, and with overweight among females as a consequence of the inadequacy of dietary intake. The present findings emphasizes the need to study in depth the different factors that affect nutritional status of elderly individuals in our country.

Aged↗
PubMed1996

[Food intake and biochemical variables: overall nutrition and metabolic status of a group of non-institutionalized elderly in Venezuela].

To evaluate the quality of life, and to establish local reference standards, the nutritional and metabolic status were assessed in two-hundred-eleven non-institutionalized adults divided in two groups: the experimental (> or = 60 years old), and the control (< 60 years old). The anthropometric nutritional status was assessed with the Quetelet Index with no significant differences between the age groups. The 24-hour recall method in the dietetic evaluation showed a high lipid and protein diet, which is characteristic of the region. The diet is deficient in energy, carbohydrates, fiber, copper, and zinc. Biochemical determinations of zinc, copper, total protein, albumin, alkaline phosphatase, triglyceride, total cholesterol, HDL-cholesterol, LDL-cholesterol, glucose, and insulin, were performed on 12-hours fasting subjects without significant (p < 0.05) age-based differences, except albumin levels, which reflects overall protein status. On the other hand, albumin, trygliceride, total cholesterol, HDL-cholesterol, LDL-cholesterol, and copper levels showed sex-based and age-sex-based significant differences (p < 0.05). Similar studies should be made on institutionalized or free-living individuals, from different socioeconomic levels and a nutritional status assessed by anthropometric measures, body composition, and food intake.

Aged↗
PubMed1993

Binding of bovine papillomavirus E1 to the origin is not sufficient for DNA replication.

Replication of the bovine papillomavirus (BPV-1) DNA requires both the viral E1 and E2 gene products. The minimal origin of replication, which resides in a 60-basepair fragment centered on the unique HpaI site of the BPV-1 genome, can be bound by the E1 protein and is flanked by E2 binding sites. The integrity of the region surrounding the unique HpaI restriction enzyme site is important for E1 binding and DNA replication, but the E2 binding sites are not required. The ability of E1 to complex with E2 and the requirement for both factors in DNA replication have led to the hypothesis that the E1/E2 complex may have a direct role in replication. Therefore we have studied mutations in the BPV-1 origin region for E1, E2, and E1/E2 complex binding and for their effect on transformation and replication in the context of the complete viral genome. Transformation and DNA replication were observed with some mutated viral genomes dramatically reduced for E1 binding. These mutated origins could bind significant amounts of E1 in the presence of E2, suggesting that binding of the E1/E2 complex could compensate for the loss of E1 binding in DNA replication. One mutation, with an eight-nucleotide insertion at the HpaI site, was still bound by E1 and the E1/E2 complex, yet did not replicate or transform efficiently. Thus although the binding of E1 or the E1/E2 complex to the origin appears to be necessary for replication, it is not sufficient.

Amino Acid Sequence↗
PubMed1986

Human esophageal carcinoma cells have fewer, but higher affinity epidermal growth factor receptors.

Squamous cell carcinomas have recently been shown to contain increased numbers of epidermal growth factor (EGF) receptors. Since EGF has an important role in epithelial growth and differentiation, it is possible that modulation of its receptor may have an important role in neoplasia. In an attempt to further explore the relationship of EGF receptor expression to malignant transformation, we examined 14 squamous cell carcinoma cell lines of the esophagus for the number and affinity of EGF receptors. Seven cell lines were newly isolated by this laboratory and recently characterized. The seven additional cell lines were obtained from Japan (4 cell lines) and South Africa (3 cell lines). Surprisingly, we found that esophageal carcinomas contained lowered quantities of surface EGF receptors (2- to 100-fold) and that the affinity of the EGF receptor was increased (6- to 100-fold) when compared to normal esophageal epithelial cells. Moreover, the biologic response of esophageal carcinoma cells to EGF differed markedly from that of other squamous cell tumor cells exhibiting elevated numbers of receptors, such as A431 and SCC-15. Human esophageal carcinoma cells were maximally stimulated by the addition of 5 ng/ml of EGF, similar to normal esophageal keratinocytes, but in contrast to normal cells were not inhibited by the higher concentrations tested (up to 40 ng/ml). On the other hand, addition of any EGF to the medium (beyond that normally present in serum) was found to dramatically inhibit the growth of A431 and SCC-15 cells. Our findings indicate that squamous cell neoplasia is not dependent upon increased numbers of cell surface EGF receptors, that EGF receptor number may have a determinant role in EGF cell toxicity, and that the stimulatory response of cells to EGF may reflect a complex function of EGF receptor number, affinity, and occupancy.

Carcinoma, Squamous Cell↗
PubMed1986

Growth and differentiation of human esophageal carcinoma cell lines.

Human esophageal carcinoma cell lines (8 cell lines) differed from their normal counterpart in terms of their morphological appearance, growth properties, and the expression of certain differentiated functions, namely keratin proteins and cross-linked envelopes. In contrast to normal human esophageal keratinocytes, the carcinoma cells were pleomorphic and tended to pile up in an unorganized fashion. When grown under optimal growth conditions the carcinoma cells generally grew to a higher saturation density than their nontransformed counterpart; their generation times were variable. Transformed cells grew better under stringent growth conditions (e.g., decreased serum and no additional growth factors except hydrocortisone) than did nontransformed human esophageal keratinocytes but their growth was still restricted under these conditions. The carcinoma cells retained a requirement for a 3T3 feeder layer when grown at clonal densities (5 X 10(3) cells/60-mm dish) but could be passaged and maintained without a feeder layer if plated at higher than clonal densities (10(5) cells/60-mm dish). All cell lines grew in an anchorage-independent fashion in soft agarose although the colony forming efficiency and size of the colonies varied among the different cell lines. Not all anchorage-independent cell lines were tumorigenic. Tumorigenic potential was greatly augmented by the use of cell lines derived from soft agarose selected clones. Altered expression of keratin proteins and cross-linked envelopes was observed in the carcinoma cell lines and generally reflected those changes seen in primary esophageal carcinomas. In two cell lines (HCE-4 and HCE-6), the synthesis of the Mr 44,000 (analogous to Rheinwald's Mr 40,000 keratin) and 52,000 keratins was suppressed coincident with the appearance of the 67 Kd keratin in tumors derived from these cell lines. These keratin patterns were once again reversed in cell lines recultured from these tumors, suggesting that the expression of these specific keratins is subject to extrinsic growth regulation. Another feature of terminal differentiation in keratinocytes, cross-linked envelope formation, was found to be significantly altered (reduced) in most but not all human esophageal carcinoma cell lines.

Animals↗
PubMed1980

Crippled lung: variations on a theme by Macleod.

We have studied nine male patients (age 18 to 68 years) with radiographic and physiologic evidence of an abnormally small lung on one side (three right and six left). All had had a childhood pneumonia or bronchiolitis and eight had chronic or recurrent bronchitis and exertional dyspnea. Radiography showed two of the small lungs to be hypolucent while seven were hyperlucent. Bronchography revealed evidence of bilateral chronic bronchitis in all with saccular bronchiectasis in three. Angiography showed strikingly diminished vascularity to the smaller lung. Spirometry revealed airway obstruction in seven of the patients. All had pulmonary arterial hypertension. Radiospirometry showed that the small lung had on the average 30% of the total ventilation but only 15% of the perfusion. Washout of 133 Xe was extremely slow in radiolucent regions. We suggest the name "crippled lung" syndrome for this entity because it is purely descriptive and encompasses several clinical variants. It also avoids the pitfalls of etiologic implication (acquired-congenital). Clinical or subclinical bronchitis seems to be common in these patients and the prime goal in therapy must be to combat the tendency towards airway infection.

Adolescent↗