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Biomedical subjects

G Varela

Publications and source records attributed to G Varela.

At least 37 records · Page 2Linked to original sources
PubMed1998

[Role of endogenous nitric oxide (NO) in pulmonary vascular adaptation to one-lung ventilation during thoracic surgery].

To determine whether endogenous production of nitric oxide (NO) increases during one-lung lung ventilation (OLV) and to observe its possible influence on pulmonary vascular resistance (PVR). The experimental group consisted of 19 patients undergoing chest surgery with OLV, with monitoring by Swan-Ganz catheter. Hemodynamic parameters were measured and peripheral venous blood samples were taken at the start of surgery and 10 minutes after starting OLV. The control group consisted of 13 patients with comparable clinical characteristics undergoing chest surgery with conventional lung ventilation. In this group samples of peripheral venous blood were taken at the start of surgery and at a moment comparable to the sampling of the experimental group. NO was assessed by quantitative colorimetry as the concentration of nitrites in venous blood. Nitrite concentration in the experimental group was higher during OLV (12.7 +/- 10.1 muMol/ml) than initially (7.1 +/- 5.4 muMol/ml) (p < 0.05). Nitrite concentration was similar at the two moments sampled in the control group (8.7 +/- 2.8 muMol/ml at the start of surgery and 8.1 +/- 3.2 muMol/ml in the second sample taken). Mean percent increase in nitrite concentration in the experimental group was 93.7 +/- 117%; mean percent change in the control group was 3.9 +/- 23% (p < 0.001). PVR during OLV (134 +/- 45 din.s.cm-5) is lower than at the start of surgery (163 +/- 37 din.s.cm-5, p < 0.05). During OLV endogenous production of NO, measured as nitrite concentration in plasma, increases. PVR decreases, possibly because of the increase in nitrite concentration.

Colorimetry↗
PubMed1998

[Descriptive study of complications caused by mediastinoscopy].

To analyze the surgical and non surgical complications of mediastinoscopy in a series of 200 consecutive patients. Retrospective study of all surgical patients between 1 January 1994 and 1 May 1997. Any complication presenting between time of surgery and patient release is analyzed. Complications were seen in 8 out of 200 cases (4%). In three cases, there were lesions in neighboring structures (recurrent nerve, bronchial artery and innominate artery). The rest were non surgical complications (3 cases of arrhythmia, 2 of prolonged mechanical ventilation). One male patient (0.5%) died from cerebral infarction, probably as a result of arterial occlusion needed to suture damage to the innominate artery. Superior win cava syndrome affected 20% (1 in 5) and morbidity was 60% (3 in 5). Morbidity involving both medical and surgical complications in this series is higher than that reported elsewhere in the literature, in series for which non surgical complications go unreported.

Aged↗
PubMed1998

[Follow-up of patients with non-small-cell pulmonary cancer undergoing complete resection. Should surgeons be in charge?].

To evaluate the effectiveness of patient follow-up after complete lung resection for non-small cell carcinoma in the same unit where the patients were treated. Retrospective review of outpatient clinic records of patients undergoing surgery for lung cancer between January 1994 and December 1996 who met the following conditions: histologically complete resection (segmentary and wedge resections were excluded) and survival at least three months after surgery. Follow-up was in accordance with preestablished guidelines that included taking the patient's medical history and performing physical examination, simple chest X-ray, hematocrit and biochemical parameters, chest and abdominal computerized tomography (CT) and periodic bronchoscopy. In 103 cases followed for between three to 34 months, 27 recurrences were detected (13 remote, 11 local and 3 local and remote). The clinical diagnosis of recurrence was made by case history adn physical examination in 18 cases, by simple chest film in 3, by biochemical blood parameters in 2, by fiber optic bronchoscopy in 2, and by CT findings in 2. One of the patients with local recurrence (bronchial stump) underwent a second operation 11 months after the first. Most recurrences are detected during simple checkups that can be performed without hospital admission. Only one patient underwent surgery for a local recurrence, suggesting that follow-up by thoracic surgery units does not appear to be worthwhile.

Adult↗
PubMed1998

Use of recombinant interferon gamma in pediatric patients with advanced juvenile chronic arthritis.

Recombinant interferon (IFN) gamma was used in 10 patients, 6 to 15 years old, with juvenile chronic arthritis (JCA) for 5 to 11 years, resistant or with severe side effects to other treatments. Six patients had systemic JCA and 4 started as pauciarticular. Three of the latter became polyarticular. Treatment schedule was 50,000 IU-kg daily for 4 weeks, then 3 times per week for 3 months and twice a week up to 2 years. Eight cases had favourable clinical response. Prolonged steroid regime could be suspended in 7/8 cases who previously received it. Two patients with systemic JCA did not respond to IFN treatment. Side effects were fever (9), headache (8), chills (6), distal cyanosis, hypotension, leukopenia and myalgia (2), and vomiting (1). All were mild or moderate. IFN gamma was more tolerable than other drugs and seems to be beneficial for patients with JCA resistant to other treatments.

Adolescent↗
PubMed1997

[Perfusion of donor tissue improves the preservation of graft in heterotopic tracheal transplantation].

To assess the effect on tracheal graft preservation of perfusion of donor tissue with a Collins solution before extraction and immunosuppression of the recipient. An experimental study was performed in 36 albino rabbits with revascularized heterotopic cervical reconstruction of the trachea with omentum. The animals were distributed in four groups. Groups I (n = 9) and III (n = 9) were transplanted with non perfused donor tissue. Animals in groups II (n = 9) and IV (n = 9) received grafts perfused with Collins solution. Immunosuppression with steroids and cyclosporin was continued for 21 days in groups III and IV. In a mid portion of the trachea viewed under optical microscope, the degree of inflammation or circumferential necrosis was assessed on a scale of 0 to 9 by adding the scores for mucosa, submucosa and cartilage. The mean score for tracheal lesion was lower in group IV, with a likelihood of random difference of less than 5%. Perfusion of peritracheal tissues with Collins solution in the donor, in addition to immunosuppression decreases the extent of tissue damage in the tracheal graft.

Analgesics, Opioid↗
PubMed1996

Effect of olive and sunflower oils on low density lipoprotein level, composition, size, oxidation and interaction with arterial proteoglycans.

The atherogenicity of low density lipoproteins (LDL) may be modulated by its serum levels, structure and affinity for components of the intima, all properties that can be altered by diet. Linoleic acid-rich diets (n-G, 18:2) reduce the levels of LDL whereas those rich in oleic (n-9,18:1) are considered 'neutral'. However, LDL enriched in linoleic acid have been reported to be more vulnerable to free radical-mediated oxidation than those enriched in oleic, a potentially atherogenic property. The effect of dietary fats on other properties of LDL that may also modulate atherogenesis, such as size and capacity to interact with intima components, are not well established. We explored here how a change from an olive oil-rich diet (OO) to a sunflower oil-rich one (SFO) affects these parameters in a community with a traditional Mediterranean diet. Eighteen free-living volunteers were placed for 3 weeks on a diet with 31% of caloric intake as sunflower oil and then shifted for an additional 3 weeks to a diet in which OO provided 30.5% of the calories. The LDL after SFO had a fatty acids ratio of (18:2 + 18:3 + 20:4) to (16:0 + 16:1 + 18:0 + 18:1) of 1.06 +/- 0.11 compared to 0.73 +/- 0.06 after the OO period. Serum LDL was significantly lower after SFO than after OO. Unexpectedly, copper-catalyzed oxidation of LDL from the SFO period was significantly less than that of the particles from the OO period. The resistance to oxidation of LDL of the SFO and OO period related to alterations in content of the antioxidants alpha-tocopherol, beta-carotene and retinol, in addition to changes in size and fatty acids composition. In vitro binding of LDL to human arterial proteoglycans was also significantly lower for the SFO-LDL than the OO-LDL, a result that can also be attributed to the larger size of the SFO-LDL. Therefore, three properties of LDL: circulating levels, oxidizability, and affinity with intima proteoglycans, that may modulate its atherogenicity, were shifted in a favorable direction by diets rich in linoleic acid and natural antioxidants.

Adult↗
PubMed1996

Effects of S-adenosylmethionine on lipid peroxidation and liver fibrogenesis in carbon tetrachloride-induced cirrhosis.

BACKGROUND/AIM: The aim of this study was to investigate the effects of S-adenosylmethionine on liver peroxidation and liver fibrogenesis in carbon tetrachloride-induced cirrhosis. METHODS: Cirrhosis was induced in three groups of six rats by repeated injections of carbon tetrachloride over 9 weeks. One group of animals was treated only with carbon tetrachloride, and the other two received carbon tetrachloride plus S-adenosylmethionine (10 mg/kg intramuscularly daily) from week 3 to week 9, and from week 6 to week 9 of the study, respectively. Two additional groups of six rats, a control group and a group treated only with S-adenosylmethionine, were also studied. Glutathione concentration, thiobarbituric acid-reactive substances, collagen content, prolyl hydroxylase activity, and procollagen type I mRNA expression were determined in liver samples. RESULTS: All carbon tetrachloride-treated rats had cirrhosis at the end of the study. Cirrhosis was also present in five of the six carbon tetrachloride-treated rats receiving S-adenosylmethionine for 3 weeks, but in only one of the six rats that received S-adenosylmethionine for 6 weeks. Hepatic glutathione was significantly diminished in carbon tetrachloride-treated rats (2.7 +/- 0.3 mumol/g tissue) and returned to normal in rats receiving S-adenosylmethionine for 3 or 6 weeks (3.7 +/- 0.13 and 3.9 +/- 0.11 mumol/g tissue, respectively). The hepatic thiobarbituric acid-reactive substances were significantly lower in rats treated with carbon tetrachloride and S-adenosylmethionine for 6 weeks (98 +/- 5 nmol/g) than in rats treated with carbon tetrachloride (134 +/- 12 nmol/g) and in those treated with carbon tetrachloride and S-adenosylmethionine for 3 weeks (127 +/- 13 nmol/g). There were no differences in either hepatic collagen and prolyl hydroxylase activity between rats that received only carbon tetrachloride and those treated with S-adenosylmethionine for 3 weeks. In contrast, carbon tetrachloride-treated rats receiving S-adenosylmethionine for 6 weeks had significantly lower collagen and prolyl hydroxylase activity than the other two groups. A much greater increase in procollagen type I mRNA was found in carbon tetrachloride-treated rats than in rats treated with carbon tetrachloride and S-adenosylmethionine for 6 weeks. Furthermore, there was a significant correlation between the hepatic thiobarbituric acid-reactive substances and prolyl hydroxylase activity and hepatic collagen. CONCLUSIONS: We conclude that the early administration of S-adenosylmethionine in a model of carbon tetrachloride-induced liver injury restores glutathione levels and reduces lipid peroxidation, resulting in less advanced liver fibrosis.

Animals↗
PubMed1996

[Analysis of proliferating cell nuclear antigen (PCNA) expression in 24 cases of primary non-small cell pulmonary carcinomas and correlation with survival].

Proliferating cell nuclear antigen (PCNA) is a 36 kD nuclear protein involved in DNA replication that is believed to provide an indication of proliferation in some neoplasms. This study analyzes PCNA expression in 24 cases of primary non-small cell lung cancer using monoclonal PC-10 antibodies in paraffin embedded material. We found significant inter- and intra-tumoral variations in PCNA expression, and no statistically significant relation between the amount of PCNA expression and the size and location of tumors, index of mitosis, histological tumor type or patient age. We found a statistically significant relation (r = 0.47; p < 0.05) between survival and amount of PCNA expression in a sample of 19 cases, but no statistically significant differences in survival related to whether PCNA expression was slight (0-25), moderate (25%-50%) or high (> 50%), and no prognostic value for degree of PCNA expression.

Adenocarcinoma↗
PubMed1996

[A case control study of the relationship between diet and breast cancer in a sample from 3 Spanish hospital populations. Effects of food, energy and nutrient intake].

A case-control study was conducted to analyze the possible role of diet on the incidence of breast cancer in a group of 275 women (139 cases and 136 controls) recruited from three hospital populations (Madrid, Mérida, and Santiago de Compostela). The retrospective intake of foods was studied by a modified dietary history; from this the intake of energy, nutrients, fiber, and alcohol was derived. Intake of oils and fats was significantly higher among cases, which translates into a higher intake of lipids and vitamin E. In contrast, intake of vitamin D and legumes was significantly lower. No differences were observed regarding other foods and nutrients between cases and controls. The estimate of the odds ratio as a relative risk measure for breast cancer, adjusted and unadjusted for total energy, indicates that intake of cereals and legumes, proteins, carbohydrates and fiber is apparently a protective factor, whereas an excessive intake of meat, oils and fats and a lipid intake higher than 46% of the total caloric intake or poly-unsaturated fatty acids higher than 15 g would be a risk factor for this pathology.

Adult↗
PubMed1995

[Tracheal rupture secondary to intubation or tracheostomy].

This article describes our experience with 3 cases of iatrogenic rupture of the trachea (2 cases secondary to orotracheal intubation and 1 to tracheostomy), all of which required surgery. We discuss the indications for surgical treatment and the technique of choice, and review the literature. Based on our experience we advise early intervention and direct suture of the lesion; if mechanical support ventilation is needed, we advise using a tube with low-pressure pulmonary tamponade.

Adolescent↗
PubMed1994

[The treatment of pneumothorax by small-caliber drainage without a water seal].

The authors describe their experience in treating 72 patients with pneumothorax by placement of a drainage tube of 2.2 mm internal diameter equipped with a Heimlich valve. Full lung expansion was achieved with this method in 93% of the cases. Mean hospital stay was 4.05 days (Sx = 3.4, minimum 1, maximum 20). In 7 (10.7%) cases out of 64 who were discharged and followed as outpatients, there was recurrence of pneumothorax. With these results the authors conclude that the system used is valid for treating pneumothorax and that large drains and water seals are not necessary in most cases.

Adult↗
PubMed1994

[The description of a method for performing repeated evacuatory thoracentesis in patients with untreatable malignant pleural effusion].

Repeated drainage by thoracocentesis may be carried out in patients with untreatable malignant pleural effusion by subcutaneous insertion of an access system initially designed for the peritoneum. The catheter is inserted into the pleural cavity through thoracic tissue, facilitating repeated drainage with minimum risk for the patient with recurring malignant pleural effusion who is no longer eligible for other therapeutic procedures. We describe our initial experience in three patients with untreatable advanced neoplasms who received symptomatic treatment for dyspnea with this method on an out-patient basis for a period of between one to four months. No complications were observed except for partial obstruction of a catheter which was unblocked with urokinase.

Aged↗
PubMed1994

[Surgical alternatives in congenital tracheal stenosis].

Congenital tracheal stenosis is a rare condition with a high mortality. In a 12-year period, 5 cases (ages 5 days to 4 years) with this anomaly were treated. 4 were corrected, the operative repair consisted of segmental resection and anastomosis in one patient, and rib-cartilage tracheoplasty in the other three. The other patient died 12 days after bronchoscopy without attempt of surgical correction. Two patients died during or just after surgery, both of them presenting a similar clinical course consisting on severe air trapping, mechanical pulmonary hypertension and low cardiac output. Long-term follow-up of the survivors is satisfactory.

Child, Preschool↗
PubMed1993

Successful management of a tracheo-innominate artery fistula following placement of a wire self-expandable tracheal Gianturco stent.

The authors report a case of tracheo-innominate artery fistula secondary to tracheal perforation in an 18-year-old patient who is tetraplegic following cervical trauma. The patient had a very long tracheal stenosis, secondary to tracheostomy, which was managed by laser resection and a Gianturco stent. One of the anterior struts of the stent had eroded the trachea and the posterior wall of the innominate artery. Surgical management consisted of arterial resection, a longitudinal tracheal split incision to withdraw the stent and placement of a Montgomery T-tube. The patient has no respiratory discomfort 7 months after surgery.

Adolescent↗