Sex hormones, metabolic syndrome and kidney

In the metabolic syndrome (MS), a condition that associates three or more pathologies such as hypertension, central obesity, type II diabetes, insulin resistance and dyslipidemias, the kidneys are severely affected. The pathological alterations in the kidneys, associated with MS, may be modified by sex hormone levels. In general, estrogens are a protection against the development of cardiovascular and renal diseases in humans and experimental models, but androgens may have an opposite effect. Among the metabolic systems that can be modulated by sex hormones in the kidney, the more important are: renin-angiotensin-aldosterone system, arachidonic acid metabolism, nitric oxide system and renal extra-cellular matrix proteins. These are metabolic pathways normally associated, in order to maintain the most efficient functioning of renal hemodynamics. There is a close interrelationship between sex hormones and some pathways involved in the metabolic syndrome; also pathways can modulate each other. The circulating concentrations of hormones may determine the degree of overall pathological alterations in the syndrome.

Sex steroid hormones, cardiovascular diseases and the metabolic syndrome

The metabolic syndrome (MS) has become the new epidemic of this century. Although its associated pathologies may vary, the most common are hypertension, central obesity, dyslipidemia, low High Density Lipoproteins (HDL), high Low Density Lipoproteins (LDL), and type-2 diabetes. Several others can be present, such as hypertriglyceridemia, cardiopathies, atherosclerosis, altered levels of sex hormones, hypogonadism in men and nephropathy. Several factors such as gender, age, race, lifestyle and diet may contribute to modify its prevalence: men develop cardiovascular diseases at an earlier age than pre-menopausal women, who seem to be protected by the antioxidant properties of estrogens. The present review offers information, mostly from 2008 to the present, as well as our own work on a rat model of MS, which was developed by the administration of sucrose in drinking water. Sex steroid hormones play an important role in the appearance and development of the MS and of cardiovascular diseases. Variations in the levels of sex hormones, whether normal or pathological, may have significant influence in the onset of several diseases, metabolic syndrome components included, as well as in the behavior of tissues and organs. These are just some of the non-reproductive actions of sex hormones.

[The uncertain future of general surgery. A specialty in the process of extinction]

General surgery was the first specialty of medicine. Nowadays, it is fragmented a progressive number of specialties, and has lost many of its fields. What will be the future of general surgery? What will be its repercussion on teaching surgery? From the point of view of a professor of surgery, our specialty today has nothing like what it was in the middle of the past century. Every day, its field of action becomes more and more reduced. Probably in the future, training in surgery will be limited to 2 years of basic knowledge, before the resident goes into the specialty of his/her choice.

[Unnecessary operations in the exercise of surgery. A topic of our times with serious implications in medical ethics]

Unnecessary operations represent between 20 and 25% of total surgical practice. This article analyses causes, history, enormous economic effects and their consequences as an iatrogenic harm. Looking for a solution to the problem of unnecessary operations is urgent because these surgeries have a direct effect on the field of ethics and morality in the practice of surgery.

Insulin-induced endothelin release and vasoreactivity in hypertriglyceridemic and hypertensive rats

Insulin-elicited endothelin release in hypertriglyceridemic, hypertensive, hyperinsulinemic (HTG) rats was shown. Weanling male Wistar rats were given 30% sucrose in their drinking water for 20-24 wk. In vitro contractions of aorta and femoral arteries were elicited with 40 mM KCl. Endothelin release induced with KCl plus 50 microU/ml insulin resulted in increases in contractile responses: 41 +/- 5.9 and 57 +/- 6% for control and 65.5 +/- 6 and 95 +/- 9% for HTG aortas and femoral arteries, respectively. The endothelin ET(B)-receptor blocker BQ-788 decreased responses to KCl + insulin by 39 +/- 8 and 53 +/- 5% in control and 48 +/- 13 and 79 +/- 3.5% in HTG aortas and femoral arteries, respectively. The ET(A)-receptor antagonist PD-151242 inhibited these responses by 12 +/- 10 and 1 +/- 9% in control and by 51.5 +/- 9 and 58.5 +/- 1% in HTG aortas and femoral arteries, respectively. These results suggest that endothelin may contribute to the hypertension in this model.

[History of surgical treatment of gastroesophageal reflux]

There exists, in our times, a great confusion concording the different techniques for the treatment of gastroesophageal reflux. Today, for instance, we use the name "fundoplication" for different operations that, in many occasions, have nothing to do with the original description of the technique. It can be said that there exists a great lack of knowledge of the historical origins and of the evolution of all of these operations. The authors of this article have done a large-scale review of the original publications, as they appeared, for the first time, in medical literature.

[30 years' experience with posterior fundoplasty in the treatment of gastroesophageal reflux (analysis of 1499 cases)]

Posterior fundoplasty, is an antireflux procedure we introduced in 1966 after experimental laboratory trials and published in 1969. To data, we have operated more than 2,000 cas. Although we now also use laparoscopic procedures, the present study reports our experience with 1499 patients who underwent the conventional procedure and who have been followed for 4 to 30 years. Mortality has been nil and mean failure rate was 9.6%. One important feature of this technique is the low incidence of undesirable effects: 3.66% dysphagia (none required dilatation), 3.94% impossibility to vomit, and 4.94% difficulties in belching. This study establishes comparisons between this group of 1499 patients and another group of 68 patients who underwent the original Nissen procedure performed under laparoscopy by the same surgeon and followed for a similar period. Such a larger personal series followed for 30 years is rare in the medical literature.

An approach to the historical evolution of surgical operations for the treatment of gastroesophageal reflux

There exists great confusion concerning the different techniques for the treatment of gastroesophageal reflux. For instance, we apply the term fundoplication to different operations that often have nothing to do with the original description, and there is a serious lack of knowledge of the historical origins of many of these operations. This analysis is the result of a large review of the operations, and of the original papers as they were published.

Endothelin mediation of insulin and glucose-induced changes in vascular contractility

Although the prevalence of hypertension in diabetic patients is high and many factors participate, hyperinsulinemia cannot be discarded as a contributing factor. Insulin could act directly on smooth muscle altering intracellular calcium levels that mediate contraction and glucose transport or could induce the secretion of endothelin by the endothelial cells lining the vessels. The aim of the present report was to study the effect of different glucose and insulin concentrations on rat vascular smooth-muscle contractile characteristics and to determine whether insulin effects are mediated by endothelin. Femoral arteries obtained from Wistar rats were placed in an in vitro chamber and superfused with different glucose and/or insulin solutions. The contractile response to KCl 80 mmol/L, measured by the force generated, showed a significant decrease with high extracellular glucose concentrations (11 mmol/L). Insulin caused a dose-dependent increase in arterial contraction induced by KCl. This increase was significant when arteries were stimulated with 80 mmol/L KCl in the presence of 5.5 mmol/L glucose, but when 40 mmol/L KCl was used, an increase was observed with both 5.5 and 11 mmol/L glucose. The insulin-induced contraction was significantly reduced in the presence of hyperimmune anti-endothelin serum and in the presence of endothelin receptor ET(A) and ET(B) antagonists PD 151,242 and BQ-788, respectively. These results suggest that hyperinsulinemia and hyperglycemia may contribute to hypertension in diabetes and that responses to insulin are mediated partially by endothelin, thus explaining why non-insulin-dependent diabetes mellitus patients show an increase in arterial pressure before the onset of nephropathy.

Esophageal fibrovascular polyp protruding from the mouth

A case of a 66-year-old woman with a giant fibrovascular polyp protruding from the mouth is presented. The polyp was successfully removed by a cervical esophagotomy.

[An operative primary health care services model including physicians and technicians]

The operative Model of Primary Health Care, was developed to offer health services to a population living under conditions of extreme poverty in the municipality of Chimalhuacán, State of México. This article describes the theorical framework, organization and operationalization of an innovative model, changing the current paradigm of clinical practice to include allied health personnel with and especial training. At the core of the model is the Basic Unit of Primary Care that includes one physician and five allied health technicians for each 15,000 habitants. This model offer an alternative to improve the utilization of available personnel and infrastructure. Finally this paper emphasizes the importance of the permanece, surveillance and evaluation of the model.

Effects of alpha adrenergic stimulation on time independent potassium current of isolated ventricular myocytes

The role of alpha adrenergic receptor stimulation on ventricular electrical activity is controversial. The aim of the present paper was to study a wide range of concentrations of alpha adrenergic agonists on the electrical properties of guinea pig's heart isolated ventricular myocytes. The experiments were performed according to the single electrode voltage clamp technique. Phenylephrine and epinephrine (in the presence of propranolol) were used at concentrations from 1 x 10(-9) to 10(-5) M. It was observed that both agonists induce an increase in the time independent inward rectifying potassium current (IK1), that could explain the shortening of the action potential. All the observed effects were dose-dependent and disappeared during washout. These results could explain, at least partially, some of the electrical changes observed during ischemia.

Different mechanism for insulin induced and contraction induced increases in skeletal muscle glucose uptake

Glucose facilitated diffusion into cells depends on concentration gradients between intracellular and extracellular spaces and can be modified by several factors such as insulin and contractions. Calmodulin participates in the insulin induced recruitment of vesicles containing glucose transporter molecules and its inhibition by trifluoperazine blocks insulin increases in glucose uptake. In the present study we tested if calmodulin inhibition with trifluoperazine blocks hindlimb muscle glucose uptake increase induced by contractions. Trifluoperazine does not inhibit exercise induced increases in glucose uptake; therefore, the mechanisms by which insulin and functional activity increase glucose uptake are different.

Regulation by glucose availability of tension development and electrical activity in fetal and neonatal rat hearts

The aim of the present article was to study if changes in glucose availability modify the functional activity of the glucose-dependent developing heart. Our data indicate that a decrease in glucose availability increases tension development and action potential duration at early fetal stages. This fact could probably be explained by the enhancement of Ca2+ movements that regulate the number and turnover rate of membrane glucose transporters in muscle cells. The sensitivity to glucose availability decreases postnatally as the heart becomes fatty acid-dependent.

[The development of cardiac function and its relation to metabolism during the perinatal period]

Several aspects of heart development are reviewed such as development of excitability and electrical and mechanical activity of the heart. Special emphasis is made upon metabolic changes during heart development and its possible consequences on electrical and mechanical activity.

Trifluoperazine inhibition of insulin-induced increase in skeletal muscle glucose uptake

The ability of trifluoperazine, a calmodulin blocker, to prevent increases in skeletal muscle glucose uptake induced by insulin was tested. Insulin significantly increased glucose uptake by the rat hindlimb and trifluoperazine (10(-6) M) completely inhibited this increase. We conclude that calmodulin is a factor involved in the regulation of insulin-mediated glucose transport in muscle cells.

Effects of maternal protein-calorie malnutrition on the phospholipid composition of surfactant isolated from fetal and neonatal rat lungs. Compensation by inositol and lipid supplementation

The effects of a maternal protein-calorie malnutrition during gestation and lactation were analyzed on fetal and postnatal lung growth and maturation, including a surfactant fraction isolated from lung tissue. There was a considerable reduction in body weight and in wet and dry lung weights of malnourished pups. Lung protein and DNA concentrations were similar in both groups except in late gestation (lung hyperplasia) and 2 and 15 d after delivery (hypocellularity). Lung glycogen breakdown was slowed down in malnourished newborns. Surfactant material was decreased the most perinatally and the reduction was more marked than for the nonsurfactant fraction of the lung. Disaturated phosphatidylcholine, the major surface active surfactant component, was decreased the most at birth (1.70 +/- 0.31 nmol/mg wet wt versus 3.68 +/- 0.17 nmol/mg in controls, n = 8) and on d 2 (5.04 +/- 0.53 nmol/mg versus 7.67 +/- 0.44 nmol/mg in controls, n = 8). There was an apparent recovery in the composition of surfactant in malnourished rats 5 d after delivery, due in fact to a decrease in controls, and an actual return to normal levels 15 to 20 d after birth. Postnatal lipid supplementation with Intralipid led to partial recovery on d 10. Inositol supplementation totally reverted the effects of malnutrition on surfactant phospholipids (8.36 +/- 0.94 nmol disaturated phosphatidylcholine/mg wet wt on d 2 versus 7.67 +/- 0.44 nmol/mg in controls and 5.55 +/- 0.62 nmol/mg in untreated malnourished rats, n = 10; 2.43 +/- 0.32 nmol disaturated phosphatidylcholine/mg wet wt on d 10 versus 3.26 +/- 0.32 nmol/mg in controls and 1.18 +/- 0.27 nmol/mg in untreated malnourished rats, n = 8).(ABSTRACT TRUNCATED AT 250 WORDS)

Changes in brain glucose retention produced by the stimulation of an insulin-sensitive reflexogenic zone in rats

Although it has been reported that insulin decreases glucose efflux from the brain causing an increase in brain glucose retention, its mechanism of action is still unknown. The present results indicate that peripheral insulin may act through the stimulation of insulin-sensitive receptors localized in the region irrigated by the coeliac trunk and innervated by the vagus nerve. Stimulation of this zone in anaesthetized, artificially ventilated rats with a bolus millidose of insulin (50 mU) caused a significant increase in brain glucose retention as a result of decreased glucose efflux from the brain. The same dose of insulin injected 1-2 cm caudally in the abdominal aorta below the coeliac trunk failed to increase brain glucose retention. The effects of insulin above the coeliac trunk disappear when the vagus nerve is sectioned, suggesting that the vagus participates as the afferent pathway of this reflex.

Compensation by fetal erythrocytes of plasma glucose changes in rats

Changes in plasma glucose and glucose and glycogen content in fetal erythrocytes (FRBCs) were studied in rats between days 15 and 21 of gestation and in adult rats. Plasma and FRBC glucose concentrations increased during fetal life and were higher in erythrocytes than in plasma. Glycogen was higher in FRBCs than in adult erythrocytes and tended to decrease from day 15 to 19 of gestation and to increase again on day 21. When FRBCs were incubated in vitro in different glucose concentrations to study their capacity to compensate for changes in plasma glucose concentration, younger cells showed better glucose-buffering capacities. Glucose and glycogen levels in FRBCs increased when they were incubated in high-glucose medium, and the glycogen concentration reached was higher in the early fetal stage than by the end of gestation. Nevertheless, adult erythrocytes accumulated more glycogen in high-glucose medium than cells from any of the fetal-aged erythrocytes. When glucose was injected intraperitoneally into fetuses of different ages, there was an increase of 3.7 microM/ml in glucose concentration in blood from the umbilical artery and 2.5 microM/ml in blood from the umbilical vein. FRBCs buffered some of this change, as evident by an increase in glycogen content. Again, buffering capacity was greater for erythrocytes in younger fetuses. Epinephrine diminished glycogen concentration in venous FRBCs on days 19 and 21 of gestation even in hyperglycemia. Insulin diminished glucose concentration in arterial plasma on days 17 and 21 of gestation, but there were no changes in glucose and glycogen in FRBCs.(ABSTRACT TRUNCATED AT 250 WORDS)

The posterior fundoplasty in the treatment of gastroesophageal reflux

The fundoplasty in the treatment of gastroesophageal reflux is essentially a modification of the Nissen fundoplication with the same percentage of effectiveness in the control of reflux but with a lower rate of undesirable side effects. The procedure is easy to perform. The author has performed this procedure more than 1,500 times within the last 20 years with very satisfactory results.

Erythrocytes and glucose homeostasis in rats

The capacity of erythrocytes to modify their glycogen stores to compensate for changes in glucose concentration in plasma was studied. Experiments in vitro and in vivo demonstrated that erythrocytes absorbed and incorporated glucose into their glycogen stores when glucose concentration in the medium was high and liberated it when the concentration was low. Epinephrine administration inhibited glucose absorption by erythrocytes, and in its presence, erythrocytes liberated glucose from their glycogen stores, being unable to compensate for this rise in glucose concentration in plasma. Similar results were obtained when endogenous secretion of epinephrine was enhanced by carotid sinus-chemoreceptor stimulation. Insulin had no effect on the capacity of erythrocytes to absorb glucose. These data suggest a role for erythrocytes in the transport of glucose to different regions in the organism's circulation and in the regulation of glucose concentration in plasma.

The Heyrowsky operation associated with fundoplication for the treatment of patients with achalasia of the esophagus after failure of the cardiomyotomy

In six patients with achalasia of the esophagus who previously underwent, one or more times, cardiomyotomy and had a failure of the procedure, we have done a new operation, an abdominal laterolateral anastomosis between the esophagus and the gastric fundus (Heyrowsky), wrapping it up with the stomach to form a genuine fundoplication. The six patients were preoperatively and postoperatively evaluated roentgenographically, endoscopically and manometrically, and the results were good with no reflux, and the drainage effect of the operation was excellent. This technique is a recourse for patients who have a recurrence of dysphagia after the Heller operation, because it has been ineffective, since it sometimes occurs in a rather large megaesophagus.

Ten year evaluation of posterior fundoplasty in the treatment of gastroesophageal reflux: long-term and comparative study of 135 patients

Results over a 5 to 10 year period in 135 patients with hiatal hernia treated surgically by posterior fundoplasty were compared with results in a similar group of 40 patients undergoing Nissen fundoplication. The final results demonstrate the effectiveness of both procedures to relieve gastroesophageal reflux. However, the collateral effects with posterior fundoplasty are considerably less than those with the Nissen fundoplication. The lower esophageal sphincter was longer with fundoplasty than with the Nissen procedure.