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Biomedical subjects

A Fernandez

Publications and source records attributed to A Fernandez.

285 records · Page 16Linked to original sources
PubMedDate not supplied

Reduced noradrenaline responsiveness of brown adipocytes isolated from estradiol-treated rats.

High plasma levels of estradiol are known to reduce the GDP binding of brown adipose tissue. Since GDP binding depends on the level of sympathetic discharge to brown adipose tissue, we measured the responsiveness to noradrenaline of brown adipocytes isolated from female rats with high plasma levels of estradiol. Noradrenaline responsiveness was assessed by measuring the respiration rate of isolated brown adipocytes in the presence of different concentrations of noradrenaline. Both control and treated adipocytes showed the same basal respiratory rate (27 +/- 6 and 24 +/- 4 nmol O2.min-1.10(-6) cells, respectively). The presence of noradrenaline (0.1, 1, and 10 microM) in the medium increased the respiration rate of both kinds of adipocytes in a dose-dependent manner. However, the response was markedly reduced in adipocytes isolated from estradiol-treated rats. These results suggest that estradiol impairs the responsiveness of brown adipose tissue to the sympathetic nervous system. Three possible mechanisms are suggested as accounting for the observed decreased responsiveness to noradrenaline, i.e., a direct action of estradiol in brown adipocytes, a modulatory role of estradiol in the central control of the sympathetic discharge to brown adipose tissue, and the interference of catecholestrogens with noradrenaline synthesis at the sympathetic terminals.

Adipocytes↗
PubMedDate not supplied

Intensive care during prolonged anhepatic state after total hepatectomy and porto-caval shunt (two-stage procedure) in surgical complications of liver transplantation.

BACKGROUND/AIMS: Recently, total hepatectomy and temporary porto-caval shunt has been indicated in surgical complications of liver transplantation. Four cases of liver transplantation which presented liver hemorrhage at the time of implant, and a 5th case with surgical trauma of hepatic hilum are presented. METHODOLOGY: The graft was removed and a porto-caval shunt was performed in all patients. Retransplantation was possible in all recipients, after an anhepatic period of 16-24 hours. RESULTS: Early persistent ionic hypocalcemia and late olyguric renal failure were the most constant and prominent complications during the anhepatic period. Two patients died of renal failure and respiratory distress syndrome at 6 and 28 days, respectively, after liver transplantation. The other 3 patients are alive and without complications at 48, 33 and 11 months of follow-up. CONCLUSIONS: Total hepatectomy with a temporary porto-caval shunt and later retransplantation must be considered as a useful procedure for surgical complications of liver transplantation which may not be treated using other techniques. Special attention should be paid to preserve renal function in the anhepatic state in order to improve survival in similar cases of two-stage liver transplantation.

Adolescent↗
PubMedDate not supplied

[Neuropsychology of temporal partial epilepsy: a comparison of drug resistant and pharmacologically controlled patients].

INTRODUCTION: Various factors may contribute to cognitive deterioration in temporal lobe epilepsy, and there is controversy as to which has the greatest effect. PATIENTS AND METHODS: In this study, we establish a comparison between patients with temporal lobe epilepsy controlled by drugs and drug-resistant patients, with the object of discovering the effect of different factors in causing cognitive damage. RESULTS: The persons whose disorder was controlled by pharmacological means had better results in memory and intelligence tests than those with drug-resistance. The latter had alterations of declarative memory for verbal material (left) and for visio-spatial material (right) in delayed free recall tests. Also, the greater proportion of symptomatic epilepsies in the drug-resistant group affected their greater cognitive deterioration. CONCLUSIONS: Our results show that having long-standing epilepsy with great frequency of seizures and symptomatic epilepsy is correlated with cognitive alterations in memory function in temporal lobe epilepsy. Most deterioration is seen in patients with long-standing drug resistant symptomatic left mesial temporal epilepsy.

Adolescent↗
PubMedDate not supplied

[Bact-Alert system for hemocultures: evaluation of terminal subcultures].

Few laboratory microbiological procedures are as important as the isolation of microorganisms from blood. To evaluate the usefulness of the terminal subcultures, 5669 blood cultures giving negative results after 7 days of incubation in the Bact/Alert System (Organon Teknika) were studied. Bottles were distributed as follows: 1562 adult aerobic bottles, 119 adult anaerobic bottles, 3960 pediatric bottles and 28 FAN bottles. From 5669 blood cultures, 10 subcultures that yielded growth had not been detected by the system. These included 5 adult aerobic bottles and 5 pediatric bottles, 7 of these microorganisms were considered contaminants according to clinical data (2 Micrococcus spp, 1 staphylococci coagulase negative, 1 Burkholderia cepacia, 1 Peptoestreptococcus spp, 1 Corynebacterium spp, 1 Scedosporium spp) while the other 3 were considered true bacteremia (1 Pseudomonas aeruginosa, 1 Proteus mirabilis, 1 Streptococcus sanguis), although no one made any change in treatment on the basis of the previous isolation. Based on these results the routinary utilization of terminal subcultures is not advisable and should be used only for special cases or a second system of blood culture should be added according to clinical or epidemiological data.

Adult↗
PubMedDate not supplied

Heterogenous expression of the EGF-receptor in human breast carcinoma.

The epidermal growth factor receptor was analyzed in the membrane fraction from a series of human breast carcinomas using a radioligand assay. The results were compared to immunostaining with monoclonal antibodies on tissue sections. All tumors with detectable receptor levels as measured by ligand binding showed a positive staining with monoclonal antibodies. In such tumors more than 50 percent of the cells were receptor positive with varying intensity. Tumors classified as receptor negative with the radioligand assay could be divided into two major groups based on their immunostaining. The largest group showed no reactivity with monoclonal antibodies. In a second smaller group, a positivity was observed in small clusters of tumor cells while the majority of cells were negative. The staining intensity in such clusters was usually low. It seems possible that this heterogenous expression of the epidermal growth factor receptor is of significance with respect to clonal selection in tumor spreading.

Antibodies, Monoclonal↗
PubMedDate not supplied

[Anesthesia for bronchoscopy].

Fiberoptic bronchoscopy is a valuable diagnostic and therapeutic procedure in many clinical situations and is relatively simple to perform with the proper techniques. Local anesthetic techniques are often preferable for bronchoscopy since the examination is mostly undertaken as outpatient procedure. When the topical anesthesia is supplemented with light sedation, the procedure is easier and more acceptable to the patient. We describe a very efficient technique based on the transtracheal injection of a minimal amount of lidocaine directly on the upper airway mucosa, producing adequate anaesthesia. The method is easy to perform and safe.

Anesthesia, Local↗
PubMedDate not supplied

Role of the proline residues on the immunogenic properties of a P. falciparum circumsporozoite peptide linked to a carrier protein.

The circumsporozoite (CS) protein of P. falciparum contains an immunodominant epitope, NADP, that is repeated 37 times in the native molecule. The presence of proline in the coat proteins of the Plasmodium parasite at various developmental stages and strains is a frequent occurrence. In this study we evaluate the influence of substitution of proline residues by glycine on the immunogenic behavior of two tandemly repeated peptides linked via glutaraldehyde to a protein carrier: The (NANP)4 P. falciparum circumsporozoite peptide and its glycine-substitute analog, (NANG)4. The results obtained show that the (NANP)4 induces antibodies which recognize the peptide free in solution, bound on a solid phase, and linked to a carrier protein. It has been previously reported that such antibodies recognize the antigenic sites of the peptide in the native protein on the surface of the sporozoite. Antibodies raised against (NANG)4 in the same experimental conditions as (NANP)4, cannot recognize the peptide free in solution or bound to the solid phase. However, these antibodies can react with the peptide when it is linked to a protein carrier. The coupling of a glycine-containing analog to a carrier results in a significant shift in its conformation, allowing it to be recognized by the antibodies.

Animals↗
PubMedDate not supplied

ras-induced neoplastic transformation and sensitivity to tumor necrosis factor.

Tumor necrosis factor (TNF) is toxic to many tumor cells but not to normal cells. We previously reported that transfection of TNF-resistant C3H10T1/2 fibroblasts with a mutant Ha-ras oncogene induced tumorigenicity as well as TNF sensitivity. To investigate the relationship between tumorigenic transformation and TNF sensitivity, we isolated TNF-resistant revertants from Ha-ras transformed TNF-sensitive cells and analyzed them for p21 expression and tumorigenic potential. The TNF-resistant cells expressed the same amount of mutant p21 as TNF-sensitive cells and retained their tumorigenic potential. In fact, TNF-resistant cells were more tumorigenic than TNF-sensitive cells. These results suggest that mutant p21 expression is directly associated with tumorigenic transformation, while acquisition of TNF sensitivity is incidental to the process of neoplastic transformation. It is possible, however, that ras-induced TNF sensitivity and transformation are regulated by different effector molecules downstream of Ras.

Animals↗
PubMedDate not supplied

[Laparoscopic cholecystectomy. Report of the first 1300 cases carried out by a multidisciplinary team].

Nowadays, the laparoscopic cholecystectomy has been accepted as the more effective and safe procedure for the treatment of symptomatic gallstones. The present issue shows the initial result in the management of 1300 patients undergoing laparoscopic cholecystectomy, by a surgical team integrated by experienced endoscopist and surgeons. The diagnosis and treatment of common duct stones were performed preoperatively in 35 patients (2.7%). The ERCP, with endoscopic sphincterotomy and stone extraction was performed in all cases. The overall conversion rate to open cholecystectomy was 0.8%. The technical difficulty to identify the structures was the more frequent cause of conversion. On the other hand, the complication rate was 2.5%, there were no bile duct injuries, and the mortality associated was 0.15%. The 92.8% of our patients was discharged within 24 hours of surgery. We conclude that the medical team, integrated by endoscopist and surgeons, offer to patient an organic and sequential management of their illness; moreover, this was decisive to obtain lower rate of complications, mortality and conversion.

Adolescent↗
PubMedDate not supplied

[Surgical treatment of lung abscesses].

The authors analysed a group of patients with lung abscesses that received surgical treatment, as well as the characteristics of their evolution. Seventeen patients with lung abscesses which underwent surgical therapy from 1984 to 1995 were analysed. The group was composed of 12 male and 5 female. The age varied from 25 to 78 years (mean-50.1 years). The etiologies were: post-pneumonic, tuberculosis, foreign-body, empyema. Two types of surgical procedures were performed: pulmonary resection and transthoracic drainage. The indication of surgery was based on the failure of clinical treatment, massive hemoptysis, pleural empyema and residual cavity wider than 2 cm after 6 weeks of clinical treatment. The patients with poor clinical conditions were selected to transthoracic drainage, the less invasive procedure. Most patients had a satisfactory post-operative evolution (58.9%). Five patients had complications (29.4%) as empyema and air leak for more than three weeks and two patients died (11.9%). Regarding the surgical technics, the pulmonary resection (lobectomy and segmentectomy) showed no morbidity and mortality. The usage of external chest tube drainage of the abscess had a morbidity of 40% and mortality of 20%. In conclusion, the complicated lung abscess is still a surgical pathology and the best approach seems to be the resection of the pulmonary segment affected. The drainage has specific indication, mainly in patients with deteriorating condition, but this procedure has high mortality and morbidity rates.

Adult↗