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Biomedical subjects

M A Simón

Publications and source records attributed to M A Simón.

At least 37 records · Page 2Linked to original sources
PubMed1990

Chronic and endogenous regulation of insulin receptors by catecholamines in adipocytes from patients with a phaeochromocytoma.

Insulin binding in adipocytes from patients with a phaeochromocytoma (PH) approached that of the controls (C) at low and higher concentrations of unlabeled insulin. The apparent receptor affinity was unchanged (ED50: PH 0.50 x 10(-9) M and C 0.60 x 10(-9) M). Scatchard analysis of the binding data using the negative cooperative model revealed a 46% decrease in the total number of receptors together with no changes in both K-e (PH 0.55 x 10(9) M-1 and C 0.36 x 10(9) M-1) and K-f (PH 0.13 x 10(9) M-1 and C 0.07 x 10(9) M-1). According to the two site model, an altered proportion in the two classes of insulin binding sites was detected. This was accompanied by a catecholamine-desensitization of the adipocytes to the antilipolytic action of insulin. These events could represent a final situation of a chronic and endogenous regulation by high levels of catecholamines of insulin receptors in human adipose tissue.

Adipose Tissue↗
PubMed1989

[Complications of acute gastroenteritis caused by Salmonella no typhi].

A review was made of the histories of 125 adult patients admitted for acute gastroenteritis (GEA) due to Salmonella no typhi. The complications that appeared in the series are analyzed. A total of 16 patients (12.8%) presented complications: the most common was bacteremia, 3 had renal tubular necrosis, 2 alithiasic cholecystitis that required surgery, 2 toxic megacolon, 2 rectal hemorrhage, 1 erythema nodosum and 1 intestinal perforation. The authors review the features of each complication.

Acute Disease↗
PubMed1989

[Carcinoma of the colon in La Rioja. Study of incidence in the period 1978-87].

A study was made of the incidence of colonorectal tumors in the Autonomous Community of La Rioja (Spain) over 10-year period between 1978 and 1987, inclusive. An increased incidence of these tumors is confirmed, with no decline in the age of presentation or in the frequency of detection of early tumors, which suggests that this disease is on the rise. In view of these results, measures leading to the early diagnosis of colonic tumors are needed, such as screening of the general population, particularly groups at risk.

Aged↗
PubMed1989

[Results of extended resections in colorectal cancer].

We present 50 cases of super-radical surgery in cancer of the colon and rectum with tumoral spread. In the same period of time a total of 426 colorectal neoplasms were operated on, which represents 11% of the total. The mean age was 65.7 years, with a predominance of females (29/21). In every case the primitive tumor and contiguous organ affected were excised with an oncologic criterion; the principal location was the rectum, with 14 cases, and the viscus most affected was the female genital tract. The mean hospital stay was slightly longer than that of the general series (20.9/14); the mortality was 4%, a figure similar to that of the general series; the index of morbidity did not rise, survival was comparable and the patient's comfort was enhanced. In our opinion, this technique is indicated in all cases in which the tumor invades contiguous regions when local and/or general conditions permit.

Adult↗
PubMed1989

[Immediate prognosis factors in total gastrectomy in cancer].

We present a series of 76 patients operated over a period of nine years, diagnosed as gastric cancer (CG), in whom radical oncologic total gastrectomy (GT) with esophago-jejunal anastomosis (EY) on a Roux-en-Y loop (Y-R) was performed. The tumor was located in the cardias in 27 patients, body in 37, fornix in 3, gastric stump in 7 and over plastic linitis in 2. We performed total gastrectomy enlarged to the spleen in 63 patients, to the pancreas in 28, to the colon in 5 and to the liver in 4. We describe the most salient technical details of the surgical intervention. Twenty-six percent of the patients presented postoperative complications, which we divided into two groups: anastomosis failures, among which are emphasized 4 severe esophagojejunal fistulas, a fistula of the duodenal stump (MD) and respiratory complications. The mortality was 7.8%, corresponding to 4 esophago-jejunal fistulas, 1 fistula of the duodenal stump and 1 bilateral bronchopneumonia. We analyzed various parameters that we consider important prognostic indicators of postoperative morbi-mortality. Applying the Fischer test, we attempted to assign statistical significance to these parameters. Age over 60 years increased postoperative mortality. Super-radical surgery did not increase mortality. On the other hand, patients in stages IIIb and IV have a worse prognosis, with a mortality in the first 30 days of 28.5%. Esophago-jejunal anastomosis on a Roux-en-Y loop is the procedure of choice used by our center after total gastrectomy for gastric cancer, yielding the most acceptable morbi-mortality figures.

Adult↗
PubMed1989

[Non-excisional treatment of spontaneous rupture of the esophagus].

We present 7 personal cases of Boerhaave syndrome, 6 treated surgically and one managed with conservative measures. Boerhaave's syndrome is one of the most serious gastro-intestinal perforation pictures. Although its frequency is scant, because of its seriousness it is important to be aware of it for early diagnosis. While a prompt diagnosis is important in any pathology, it is even more so in this syndrome since there is a clear relationship between the time lapse from perforation to the onset of treatment and the rate of survival. Although we present one case cured medically, this is exceptional and treatment is eminently surgical and should be as early as possible. The technique that provides the best results and an excellent morbimortality rate in relation to efficacy is primary suture followed by a fundal patch. In delayed cases with patients in deteriorated condition, other techniques can be considered. Due to its initial severity and a tendency to postoperative complications, the patient should be closely controlled, and correct antibiotic therapy and complete parenteral support nutrition are very important in treatment.

Adult↗
PubMed1988

Characterization of somatostatin binding sites in isolated rat adipocytes.

Somatostatin binding sites were characterized in isolated rat adipocytes. The binding was found to be saturable, reversible, and time- and temperature-dependent. The somatostatin binding sites are principally located on the cell surface. 125I-[Tyr11]somatostatin binding was not inhibited by glucagon and angiotensin II. By contrast, native somatostatin and somatostatin-28 displaced labeled peptide with a similar ED50: 50 nM. Scatchard analysis pointed to the existence of two classes of binding sites, with a Kd of 7.64 nM for the high-affinity sites and a Kd of 295 nM for the low-affinity ones. Comparison of somatostatin receptor binding and its lipolytic action in isolated rat adipocytes suggested that the spare receptor phenomenon cannot be applied to the lipolytic action of somatostatin in rat adipose tissue.

Adipose Tissue↗
PubMed1987

Adrenergic receptors are not mediators in the lipolytic effect of somatostatin in rat adipocytes.

Beta-adrenergic receptors have been purported to act as possible mediators in the lipolytic effect of somatostatin in vivo. Investigations with isolated rat adipocytes studying the lipolytic activity of somatostatin (1.7 x 10(-7) M), glucagon (8.1 x 10(-8 M) and norepinephrine (10(-6) M), have shown that the lipolytic effect stimulated by somatostatin is not altered by 10(-5) M propranolol (beta-antagonist); is significantly enhanced by 10(-5) M isoproterenol (beta-agonist) and is not altered by the addition of 10(-6) M phenoxybenzamine (alpha-antagonist) or 10(-6) M phenylephrine (alpha-agonist). Similar results were found when lipolysis was stimulated by glucagon, whereas the lipolytic effect stimulated by norepinephrine was blocked by propranolol. These results indicate that the direct lipolytic effect of somatostatin on isolated rat adipocytes does not seem to be mediated through mechanisms involved with adrenergic receptors.

Adipose Tissue↗
PubMed1987

Binding and action of glucagon in isolated adipocytes from cortisol-treated rats.

Evidence for pre-receptor, receptor and post-receptor glucagon defects was investigated in adipocytes from cortisol-treated rats. A decrease in glucagon binding due to a decreased number of receptors was observed. No changes in receptor affinity were detected. Both, the lipolytic response of glucagon and the ability of glucagon to increase basal and theophylline-stimulated cAMP accumulation remained unaltered. Moreover, a hyperglucagonemia accompanied by an increase in glucagon degradation in the serum of cortisol-treated rats was observed. Such alterations could represent a new mechanism by which glucocorticoids exert their biological actions.

Adipose Tissue↗
PubMed1987

Decreased insulin binding and antilipolytic response in adipocytes from patients with Cushing's syndrome.

Human adipocytes from patients with chronic endogenous hypercortisolism (Cushing's syndrome) showed a statistically significant decrease in insulin binding at low unlabelled-insulin concentrations but no change in receptor numbers (Cushing's 180,000 +/- 48,000 (3) receptors/cell and controls 189,000 +/- 30,000 (7)) together with a fourfold decrease in apparent receptor affinity (ED50: Cushing's 2.25 x 10(-9) M and controls 0.57 x 10(-9) M) and a decreased sensitivity to the antilipolytic effect of insulin. These events could represent the final situation of a chronic and endogenous regulation by high levels of cortisol of insulin receptors in human adipose tissue.

Adipose Tissue↗