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Membrane receptors for estrogen, progesterone, and testosterone in the rat brain: fantasy or reality.

1. There are numerous circumstantial evidence supporting the concept that steroid hormones control cellular function by means other than the nuclear receptor steroid binding mechanism. It is the intent of this report to present evidence indicating that steroids bind to specific sites in neuronal membranes. 2. Some of the criteria to define steroid membrane receptors using steroid-BSA conjugates that can be radioiodinated to desired specific activity have been fulfilled for each of the three sex steroids using crude synaptosomal membrane preparations (P2 fractions) from the CNS of female and male rats. Ligand binding for each of the three steroids indicate high-affinity and high-capacity sites with distinct brain selectivity and stereospecificity. For example, 17 beta-E-6-[125I]BSA binds hypothalamic P2 fractions (HYP-P2) with an estimated Kd of about 3 +/- 0.7 nM (X +/- SE; n = 3), whereas the cerebellum P2 (CB-P2) fractions bind the ligand with a Kd of 34 +/- 7 nM and, a Bmax of 3 and 42 pmol/mg protein, respectively. Estrogen and testosterone binding fit best a one-single site, while progesterone binding sites can be best represented by a two-binding site, one high-affinity (Kd = 1-2 nM) and one low affinity (Kd = 62 nM), in CB-P2 fractions from intact adult female rat brain. Kinetics studies for T-3-[125I]BSA indicate that the estimated Kd of 30 +/- 2 nM for the olfactory bulb P2 fractions (OB-P2) from male rats is in good agreement with Kd values computed from Scatchard-derived data using the LIGAND algorithm. 3. 17 beta-E-6-[125I]BSA binding sites are stereospecific and appears to be present as early as 5 days of age in both the OB- and the CB-P2 fractions without changes during development. In contrast, P-6-[125I]BSA binding sites are practically absent during days 5 and 12 and appear by day 22. 4. Finally, membrane receptor molecules for estrogen and progesterone have been isolated and purified by affinity chromatography and characterized by PAGE and Western blot. Microsequencing of one of the membrane estrogen binding proteins indicates that the high-affinity site corresponds to the OSCP subunit of the proton ATP synthase. 5. It remains to be determined if P and T also bind to this complex enzyme or if they bind to other subunits of the family of proton ATPases. Overall the data indicate that steroid hormones conjugated to BSA are important tools to study the "reality of membrane steroid receptors."

Animals↗

Closed chest totally endoscopic coronary artery bypass surgery: fantasy or reality?

With the introduction of the da Vinci robotic surgical system (Intuitive Surgical, Mountain View, CA) into minimally invasive cardiac surgery, the outlook of performing coronary artery bypass operations "closed chest" became a reality. Between May 1999 and July 2000 this wrist-enhanced instrumentation was used in 143 patients (107 men, 36 women, median age 63 10.3 y). Thirteen patients suffering from coronary artery disease (CAD) were treated as totally endoscopic coronary artery bypass (TECAB), 79 patients underwent a minimally invasive direct coronary artery bypass procedure, and 35 patients were treated using the robotic-enhanced Dresden Technique. Preoperative survival was 100%. All patients in the TECAB group were operated upon via a three- or four-point stab incision using the da Vinci robot for internal mammary artery takedown and for performance of anastomoses. These new robotic-enhanced surgical techniques promote an optimistic way of thinking about the further development of these procedures and its application in patients suffering from CAD.

Aged↗

Immunonutrition: fact, fantasy, and future.

Immunonutrients are molecular compounds that, while being dietary components, also influence immunologic response mechanisms. Substances such as glutamine, w-3 fatty acids, arginine, and/or ribonucleic acid have been added to standard nutritional support solutions, and the use of these formulations is known as "immunonutrition." A number of randomized, controlled trials have demonstrated that recipients of immunonutrition have better outcomes than control subjects receiving standard nutritional support. However, it is possible that standard parenteral or enteral nutrition is actually harmful. We currently lack data from randomized trials showing the efficacy of immunonutrition compared with no nutritional support. Even if such information were forthcoming, these immunonutrients may simply be acting as pharmacologic agents. Finally, because each of these nutritive agents may either up- or downregulate the immune response, the effects may be disease-state specific.

Adjuvants, Immunologic↗

Blood volume in pre-eclampsia: fantasy and reality.

A great deal has been stated recently about the importance of hypovolemia in pre-eclampsia and eclampsia from the point of view of pathogenesis and management. Some authors even believe that the so-called hypovolemia represents an etiologic factor and should be "corrected." In this paper, the hemodynamic factors that maintain the circulation in the normal nonpregnant and pregnant states are discussed. These factors are then used as a background for explaining the pathophysiologic abnormalities of the acute hypertensive disease of pregnancy. It is concluded that the slight decrease in blood volume observed in pre-eclampsia has no hemodynamic relevance; the blood volume is merely "fitting" a contracted vascular bed. The major abnormality resides in the constricted arteriolar system and not in the blood volume.

Blood Circulation↗

Fact and fantasy: psychosocial consequences of facial surgery in 24 Down syndrome children.

Twenty-four children with Down syndrome were evaluated to investigate whether appearance, family functioning and intellectual functioning improved after facial reconstruction. Pre- and postoperatively, families were interviewed by a psychosocial team, the children's intellectual functioning was measured and parents were asked to rate their child's facial appearance on the Hay's Scale and to complete the FACES II, a questionnaire determining family functioning. Parents' ratings were compared with the scores of lay raters who viewed randomly presented pre- and postoperative photographs. Measurements of intelligence and family functioning revealed no postoperative improvement and lay raters considered postoperative appearance as slightly less attractive. However, parents rated their children's appearance as noticeably improved and reported happier personal, family and social lives. Thus, positive psychosocial consequences may largely be the result of parents' satisfaction with surgical results, providing them with hope for the future. Presurgical family assessment to clarify surgical limitations and parental expectations is essential.

Adolescent↗

Rotation of the gut: fact or fantasy?

Clinicians, as well as embryologists, believe that normally a process of rotation of the midgut takes place that can be hampered at any stage resulting in the different types of "malrotations." However, a "malrotated" gut has never been observed in normal embryos. Therefore all theories on the normal and abnormal development of the gut are still highly hypothetical. In an attempt to elucidate more clearly which events occur during the development of the gut, the authors studied its embryology in 58 normal rat embryos between the 13th and 20th day of gestation using scanning electron microscopy. In 13 day old rat embryos, the midgut has already formed a loop. It can be subdivided into three parts: the central part with its connections to the stomach and leading to the straight part, with the colorectum on the left and the "small bowel" on the right, and the tip of the loop inside the umbilical cord. These three parts show no signs of developmental synchronization. Each part develops according to its own developmental blueprint: the duodenal and umbilical parts of the midgut show much developmental activity, whereas gross changes of the straight part of the midgut are not seen. This finding is surprising because a process of rotation, if occurring, should result in notable morphological changes especially in this region. Furthermore, the coecum never achieved a position in the upper left abdomen, as is often outlined in schematic drawings. After the return of the bowel into the abdominal cavity, the coecum lies exclusively on the right side of the midline close to the ventral abdominal wall.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗

Branched chain amino acids in the management of chronic liver disease. Facts and fantasies.

The liver plays a central role in protein and amino acid metabolism. It processes dietary amino acids and reprocesses amino acids released from muscle protein degradation. It utilises amino acids for protein synthesis and gluconeogenesis, regulates the supply of amino acids to peripheral tissues and converts excess amino acids to urea. In patients with liver disease the liver's ability to control both plasma and tissue amino acid fluxes may be seriously disturbed. The resultant changes in amino acid metabolism may be implicated in the genesis of the neuropsychiatric abnormalities and the deterioration in nutritional status commonly observed in patients with hepatic failure. Thus, on theoretical grounds, amelioration of these amino acid abnormalities might benefit patients with liver disease who have hepatic encephalopathy or are malnourished. However, there is, at present, no consensus as to the efficacy, practicality or cost-effectiveness of 'amino acid therapy' in patients with liver disease.

Amino Acids, Branched-Chain↗

Perspectives on formaldehyde toxicity: separating fact from fantasy.

Formaldehyde (IUPAC name, methanal) is one of the simplest, most ubiquitous molecules in our environment and troposphere. Exposure to large amounts of formaldehyde can produce a variety of respiratory and dermatologic problems in humans, in both the home and the workplace. However, in spite of anecdotal reports on formaldehyde-induced illness over the past 20 years there is a paucity of data regarding its potential as either an allergen or an antigen in humans. In addition, many of our current impressions about formaldehyde are based on studies of dubious scientific validity. In this review, we discuss the biological and chemical properties of formaldehyde and its presence in materials which we come in contact with, and finally attempt to put in perspective our current understanding of the detrimental effects of formaldehyde on our health, or lack thereof. There is no evidence at present that formaldehyde causes immunological diseases. Finally, and unfortunately, many of the studies have drawn invalid conclusions and are based on poorly controlled anecdotal observations.

Animals↗