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Biomedical subjects

C García

Publications and source records attributed to C García.

At least 199 records · Page 11Linked to original sources
PubMed1993

Tumour necrosis factor-alpha inhibits synthesis of surfactant by isolated human type II pneumocytes.

OBJECTIVE: To investigate the effect of tumour necrosis factor-alpha (TNF-alpha) on the synthesis of surfactant by human type II pneumocytes. DESIGN: Laboratory study. SETTING: University departments of surgery and biochemistry. MATERIAL: Segments of right lower lobe of lungs from nine donors of other organs, and from tumour-free portions of 10 lungs excised from patients with lung cancer. MAIN OUTCOME MEASURES: Effect of TNF-alpha on the incorporation of D-glucose and palmitate, both of which had been uniformly labelled with 14C (D-(U-14C) glucose and (U-14C) palmitate), into various phospholipid fractions by pneumocytes isolated from both healthy lungs and those from patients with lung cancer. RESULTS: TNF-alpha decreased the incorporation of both D-(U-14C) glucose and (U-14C) palmitate into phospholipid fractions, particularly phosphatidylcholine, in both healthy lung tissue and that from patients with lung cancer. The degree of inhibition was less in the group from patients with lung cancer because the basal value was lower. CONCLUSION: TNF-alpha may contribute to the pathophysiology of the adult respiratory distress syndrome by inhibiting the synthesis of surfactant. The results suggest the possibility that TNF-alpha may be produced locally in the presence of lung cancer resulting in chronic paracrine or systemic exposure of pneumocytes to low concentrations of the cytokine.

Adult↗
PubMed1993

[Ureteroscopy. Our results and complications].

From November, 1987 to December, 1990, 399 cases of ureteral calculi were treated by rigid ureteroscopy (URS). Our success and complication rates are presented. Of these, 99 (25%) had a calculus in the pelvis (78/99), iliac (15/99) or lumbar (6/99) ureter, and 300 (75%) had Sandstrasse in the distal ureter. The cases with Sandstrasse were submitted to ureteroscopy within the first 48-72 hours to remove the ureteral obstruction, prevent hydronephrosis or sepsis and to expedite treatment. If symptomatic, obstructive and/or 7 mm or more in diameter, a nephrostomy tube was placed first whenever there was sepsis [23/300 (7%) of those with Sandstrasse and 3/99 (3%) of those with a ureteral calculus] or marked dilatation of the renal cavities [29/300 (9%) and 6/99 (6%), respectively]. The success rate was 93% for the cases with Sandstrasse versus 85% for those with a ureteral calculus, and the complication rates were 5.7% versus 9%, respectively. The foregoing results confirm the high success rate and scant morbidity of ureteroscopy in the treatment of ureteral calculus and Sandstrasse.

Adolescent↗
PubMed1993

[Aztreonam as monotherapy in urinary tract infections with a systemic repercussion in patients with a relative contraindication for the use of aminoglycosides].

A comparative study has been performed to evaluate the clinical efficacy and safety of aztreonam in the treatment of urinary tract infections with systemic affectation, in a group of patients who showed a relative contraindication to be treated with aminoglycosides. The group studied was formed by 30 patients (21 females and 9 males). Mean age of said group was 78 years and percentage of patients over 65 years was 93%. Moreover, 53.3% of patients showed nephropathy, 30% diabetes mellitus and 16.6% hearing disorders. Responsible germ of the infection was identified through blood and urine culture in 24 patients (80%) being the most frequent isolated E. Coli (60%). The cure rate was of 76.6% and improvement rate was 13.3%. Three deaths happened on the studied group (10%). In a patient superinfection due to Enterococcus was detected. There were no significative adverse effects (hypersensibility reactions, hematological disorders, nephrotoxicity or hepatotoxicity). Aztreonam could be an efficacious alternative in the treatment of urinary infection with systemic affectation, caused by gram-negative germs, showing low toxicity.

Aged↗
PubMed1992

[Rapid method for identifying Escherichia coli and species of the Proteeae tribe in urine].

BACKGROUND: To evaluate the possibility of using the determination of beta-glucuronidase and phenylalanine deaminase activity directly from urine samples for rapid detection (2 hours) of the presence of Escherichia coli and species of the Proteeae tribe. METHODS: To detect beta-glucuronidase activity methyl-umbelipheryl-beta-D-glucuronic was used as a substrate. The presence of fluorescence after incubation at 37 degrees C for 2 hours indicated a positive reaction. While phenylalanine was used as a substrate for detecting phenylalanine deaminase activity, FeCl3 was added after incubation at 37 degrees C for 2 hours with a greenish color being observed indicating phenylalanine deaminase activity. RESULTS: The detection of Escherichia coli by beta-glucuronidase activity presented sensitivity and specificity of 0.91 and 0.99, respectively. The positive predictive value was 0.96 and the negative predictive value was 0.98, whereas the determination of the phenylalanine deaminase activity with the aim of detecting species of the Proteeae tribe presented the following results; sensitivity 0.92, specificity 0.99, positive predictive value 0.94 and negative predictive value 0.99. CONCLUSIONS: The determination of beta-glucuronidase and phenylalanine deaminase activities directly from urine sediment has been demonstrated as a rapid and specific test for detecting the presence of Escherichia coli and species of the Proteeae tribe, therefore it must be considered as a useful test in early diagnosis of urinary infection thereby facilitating the administration of appropriate antibiotic treatment.

Amino Acid Oxidoreductases↗
PubMed1992

Study of a Fenton type reaction: effect of captopril and chelating reagents.

The purpose of this study was to determine if captopril, an angiotensin-converting enzyme inhibitor, could interact with iron ions and so modify a Fenton type reaction. Results indicate that different degrees of thiobarbituric acid-reactive substance from deoxyribose are obtained in an ascorbate-driven Fenton system depending on the order of addition of captopril and iron to the incubation medium. Similar results were obtained with the chelating reagents ethylenediaminetetraacetic acid and diethylenetriaminepentaacetic acid, indicating that the buffer solution plays a relevant role when a particular iron complex is formed with a chelating agent. These metal complexes produce oxidizing species in a Fenton type system whose nature is discussed.

Captopril↗
PubMed1992

The role of insulin in the intestinal absorption of glucose in the rat.

1. Acute pre-treatment with either mannoheptulose or streptozotocin--both compounds acting as powerful suppressors of insulin secretion--caused a significant decrease on the in vivo rate of intestinal glucose absorption following an intragastric [U-14C]glucose administration. 2. Mannoheptulose treatment also lowered the rate of whole-body oxidation of the administered tracer. 3. Insulin had no effect on the metabolic fate of [U-14C]glucose by isolated enterocytes. 4. However, the rate of glucose uptake, measured by the oxidation of [1-14C]glucose to 14CO2 in the presence of phenazine methosulphate, was decreased by insulin at concentrations of 50-200 munits/ml. 5. In addition, the rate of transport of [U-14C]glucose by brush-border membrane vesicles was also inhibited by insulin at high concentrations (100-1000 munits/ml). 6. This indicated that insulin acts by inhibiting glucose transport in isolated in vitro preparations. 7. Acute pre-treatment with either mannoheptulose or streptozotocin caused a significant decrease in the rate of gastric emptying, measured as the distribution of [3H]insulin along the gastrointestinal tract, following an intragastric glucose load. 8. It is concluded that insulin secretion modulates intestinal glucose absorption in vivo by enhancing gastric emptying in spite of the inhibitory effects of glucose transport observed with in vitro preparations.

Animals↗
PubMed1992

Long-term myocardial effects of correction of anemia with recombinant human erythropoietin in aged patients on hemodialysis.

Long-term myocardial effects of recombinant human erythropoietin (rhEPO) therapy were investigated in nine hemodialysis (HD) patients greater than 60 years of age. Echocardiographic studies were performed before the administration of rhEPO with a hematocrit of 20.8% +/- 1.9% and repeated after 6 (period I) and 24 months (period II) of treatment, when the hematocrit was increased to 34.1% +/- 2.3% and 32.3% +/- 2.8%, respectively. Left ventricular diameters were not significantly changed by rhEPO, although they tended to decrease at the end of the study (30.6 +/- 5.3 v 27.7 +/- 3.6 mm systole, and 50.3 +/- 3 v 46.5 +/- 3.7 mm diastole). Thickness of the interventricular septum and left ventricular posterior wall remained unaltered, although there was a downward trend (14.5 +/- 5.2 to 12.8 +/- 2.8 mm and 11.7 +/- 1.9 to 10.6 +/- 1.4 mm, respectively). Left ventricular mass index (LVM) progressively decreased from 181.5 +/- 61 to 153.8 +/- 38.3 (period I) and 135.7 +/- 45.6 g/m2 (period II, P less than 0.05). Stroke volume remained unaltered in period I, but it decreased from 93.7 +/- 10 to 65.2 +/- 12.8 mL (P less than 0.001) in period II, resulting in a decrease of cardiac index (CI) from 3.93 +/- 0.86 to 2.54 +/- 0.68 L/min/m2 (P less than 0.001) at the end of the study. Heart rate did not change during the study period. Blood pressure was kept constant, although antihypertensive therapy needed to be adjusted to prevent occurrence or aggravation of hypertension in two patients.(ABSTRACT TRUNCATED AT 250 WORDS)

Aged↗
PubMed1992

Further signs of postnatal sexual differentiation in pigs.

Fourteen newborn female, and ten male pigs were injected subcutaneously with 100 mg of testosterone propionate within 24 h of birth, and ten male and nine females were used as controls and injected with vehicle alone (Sesame oil). All animals were slaughtered at 175 days of age. Reduction of testicular weight, tubuli size and testosterone concentration, together with alteration of the intertubular area was found in adult treated males. In adult treated females, the histological study of ovaries showed the parenchyma fully occupied by multiple Graaf follicles, but no corpus luteum was found. In addition, treated females never had serum progesterone levels above 2 ng/ml, whilst control females, in some cases had values close to 2 ng/ml, and in some others near to 10 ng/ml. Carcass weight and fatness were not markedly different between groups. The observations presented in this report provide further support for a neonatal component of testosterone-dependent masculinization process in pigs.

Animals↗
PubMed1992

The role of platelet-activating factor and peptidoleukotrienes in the vascular changes of rat passive anaphylaxis.

1. The role of platelet-activating factor (PAF) and peptidoleukotrienes as putative mediators of some of the vascular changes triggered by antigen was investigated in rats passively sensitized with monoclonal anti-DNP (2,4-dinitrophenyl) IgE. 2. Lethal anaphylaxis with respiratory distress, systemic hypotension, detachment of the intestinal mucosa, leukopenia and extravasation of protein-rich plasma was observed after antigen challenge of rats sensitized with partially purified monoclonal IgE at concentrations of 15 mg protein kg-1. 3. Analysis of the peritoneal fluid obtained after i.v. challenge with DNP-BSA (bovine serum albumin) showed the presence of significant amounts of PAF (101 +/- 8 pg/rat), whereas this mediator was undetectable in control animals. Leukotriene D4 was the predominant peptidoleukotriene that could be recovered after antigen challenge, and showed an extremely high concentration (92 +2- 15 ng/rat) as compared to PAF levels. 4. Extravasation of protein-rich plasma was observed shortly after challenge and reached a maximum at 30 min. Treatment of animals with i.v. PCA 4248 (1-2 mg kg-1) and WEB 2086 (1 mg kg-1), two chemically unrelated compounds which are antagonists of the PAF-receptor, produced a significant reduction of the extravasation of protein-rich plasma. 5. The same degree of protection could be afforded by MK-886, an inhibitor of leukotriene biosynthesis. Combined treatment with WEB 2086 and MK-886 provided greater inhibition of protein-rich plasma extravasation than either compound alone. PCA 4248 was also found to inhibit in a dose-dependent manner the systemic hypotension observed upon DNP-BSA challenge.6. These data indicate that the lipid mediators PAF and peptidoleukotrienes are major effectors of the vascular disturbances observed in rat passive IgE-mediated anaphylaxis.

Anaphylaxis↗
PubMed1992

Abnormalities of thirst regulation in patients with chronic renal failure on hemodialysis.

To determine whether thirst mechanisms are altered in nondiabetic patients with chronic renal failure on hemodialysis, 4 patients with an average weight gain between dialysis sessions of more than 5% of dry body weight (group I), 5 patients with less than 3% weight gain (group II), and a group of 6 healthy subjects (group III) were submitted to infusion of hypertonic saline. After infusion the subjects had free access to water. Thirst was evaluated by visual analogue rating scales. Despite similar increments of effective plasma osmolality during saline infusion, patients of group I were thirstier than groups II and III (p less than 0.005 and p less than 0.01, respectively). Changes in thirst ratings were similar in groups II and III. Osmotic thresholds for thirst onset were similar in groups II and III (288.9 +/- 8.5 and 289.8 +/- 3.4 mosm/kg, respectively), but lower in group I (277.6 +/- 7.6 mosm/kg). Nevertheless, great variations were observed in the latter group. Thus, 2 patients showed thresholds for thirst within the normal range, whereas the others had low osmolar thresholds for thirst and baseline plasma osmolalities and high basal thirst scores. During the drinking period, the patients of group I drank more (14.2 +/- 2.8 ml/kg) than those of groups II (5.3 +/- 1.6 ml/kg; p less than 0.02) and III (10.2 +/- 1.6 ml/kg; n.s.) The plasma levels of angiotensin II in uremic patients were higher than in healthy subjects, although there were no differences between groups I and II and no correlation between basal angiotensin II levels and the interdialytic weight gain.(ABSTRACT TRUNCATED AT 250 WORDS)

Aged↗
PubMed1992

[Pisa syndrome].

The Pisa Syndrome is a rare dystonic syndrome, first described by Ekbom et al. 1972 as a side effect of neuroleptic therapy and subsequently by Patel et al. 1991 as a symptom of dementia of the Alzheimer type. It consists of tonic flexion of the trunk to one side, accompanied by a slight rotation. The presentation of three clinical cases, including one without neuroleptic but with thymoleptic medication, is followed by etiological and therapeutical considerations as well as data concerning the prevalence of this rare syndrome. Finally, the question of a possible psychogenesis of this condition is discussed.

Adult↗
PubMed1992

[Mianserin agranulocytosis followed by oxitriptan eosinophilia].

A patient suffering from endogenous depression was treated with mianserin and developed agranulocytosis. After recovering from this, and with the depression in remission, the patient was given L-tryptophan. When this medication was removed from the market, due to the newly described eosinophilia-myalgia syndrome, a change was made to oxitriptan, which then caused a serious asymptomatic eosinophilia. No similar cases have yet been reported. Following withdrawal of oxitriptan, the eosinophilia disappeared. Evidence for any other cause of the condition was not found. Causes and physiopathology of drug-induced agranulocytosis and eosinophilia and the circumstances of such complications following use of mianserin and oxitriptan are discussed.

5-Hydroxytryptophan↗
PubMed1991

[Adverse reactions to intravascular contrast media].

Adverse reactions to intravascular contrast media are infrequent in radiological practice and rarely pose a life threatening risk. Contraindication to contrast injection should be evaluated and prophylactic measures taken, if available, in patients with risk factors for adverse reactions. Details of pathogenesis, frequency and management of adverse reactions for different contrast media are discussed.

Adolescent↗
PubMed1990

Localization of an estrogen receptor binding site near the promoter of the uteroglobin gene.

By means of a DNA-cellulose competitive binding assay, we have studied the interaction of the estrogen receptor with genomic fragments of the estrogen responsive rabbit uteroglobin gene. The fragments spanned from 3255 bp upstream to 1754 bp downstream of the initiation site. Only a fragment (-396/+8) showed strong affinity for the receptor. Within this fragment a unique palindromic sequence (GGTCAccaTGCCC) was found which is very similar to the canonical consensus sequence for the estrogen receptor. A synthetic oligonucleotide of that structure specifically competed for the binding of the receptor to DNA-cellulose.

Animals↗
PubMed1990

End-stage renal disease in systemic amyloidosis: clinical course and outcome on dialysis.

We studied a group of 48 patients with systemic amyloidosis and end-stage renal disease (ESRD) treated with chronic dialysis to analyze the clinical course and the factors which can influence survival. This group was compared to a control group of 63 nondiabetic patients without amyloidosis with ESRD treated with hemodialysis. The median survival of the experimental group was 52 months; 1-, 2- and 6-year actuarial survival was 72, 62, and 44%, while in the control group it was 95, 91, and 81%, respectively (p less than 0.001). Survival was significantly shorter for patients with amyloidosis who rapidly (less than 3 months) progressed to ESRD or who had an acute deterioration in renal function immediately prior to the need for dialysis. The median survival in these cases was 4 and 1.5 months, respectively. Age, the presence or the degree of renal failure at the moment of diagnosis, and the type of amyloidosis did not affect the survival of these patients. Despite a shorter period of time spent on dialysis, these patients had a similar number of hospital admissions, cardiovascular and infectious events as the control patients, but more gastrointestinal disorders (bleeding and chronic diarrhea) and blood access problems. In conclusion, amyloidotic patients maintained on chronic dialysis have high morbidity and mortality rates. Nevertheless, acceptable survival is predictable in stable patients who progress slowly to ESRD.

Actuarial Analysis↗