Reduced performance of male and female athletes at 580 m altitude

Patients with craniocervical mandibular (TMD) disorders can present with tinnitus as a primary or secondary complaint. The embryology and functional anatomy of the middle ear, temporomandibular joint, muscles of mastication and associated tendons, ligaments, blood vessels, nerves and lymphatics was found to be helpful in establishing etiologic concepts which relate tinnitus to these temporomandibular disorders. In addition to etiologic concepts, treatment modalities are described. The authors relate their experiences as well as those of others with different patient populations.     

Effects of TCDD on Ah receptor, ARNT, EGF, and TGF-alpha expression in embryonic mouse urinary tract

Lipoprotein(a) [Lp(a)] biogenesis was examined in primary cultures of hepatocytes isolated from mice transgenic for both human apolipoprotein(a) [apo(a)] and human apoB. Steady-state and pulse-chase labeling experiments demonstrated that newly synthesized human apo(a) had a prolonged residence time (approximately 60 min) in the endoplasmic reticulum (ER) before maturation and secretion. Apo(a) was inefficiently secreted by the hepatocytes and a large portion of the protein was retained and degraded intracellularly. Apo(a) exhibited a prolonged and complex folding pathway in the ER, which included incorporation of apo(a) into high molecular weight, disulfide-linked aggregates. These folding characteristics could account for long ER residence time and inefficient secretion of apo(a). Mature apo(a) bound via its kringle domains to the hepatocyte cell surface before appearing in the culture medium. Apo(a) could be released from the cell surface by apoB-containing lipoproteins. These studies are consistent with a model in which the efficiency of post-translational processing of apo(a) strongly influences human plasma Lp(a) levels, and suggest that cell surface assembly may be one pathway of human Lp(a) production in vivo. Transgenic mouse hepatocytes thus provide a valuable model system with which to study factors regulating human Lp(a) biogenesis.     

Modulation of cardiac sodium current by alpha1-stimulation and volatile anesthetics

BACKGROUND: Alpha1-adrenoceptor stimulation is known to produce electrophysiologic changes in cardiac tissues, which may involve modulations of the fast inward Na+ current (I(Na)). A direct prodysrhythmic alpha1-mediated interaction between catecholamines and halothane has been demonstrated, supporting the hypothesis that generation of halothane-epinephrine dysrhythmias may involve slowed conduction, leading to reentry. In this study, we examined the effects of a selective alpha1-adrenergic receptor agonist, methoxamine, on cardiac I(Na) in the absence and presence of equianesthetic concentrations of halothane and isoflurane in single ventricular myocytes from adult guinea pig hearts. METHODS: I(Na) was recorded using the standard whole-cell configuration of the patch-clamp technique. Voltage clamp protocols initiated from two different holding potentials (V(H)) were applied to examine state-dependent effects of methoxamine in the presence of anesthetics. Steady state activation and inactivation and recovery from inactivation were characterized using standard protocols. RESULTS: Methoxamine decreased I(Na) in a concentration- and voltage-dependent manner, being more potent at the depolarized V(H). Halothane and isoflurane interacted synergistically with methoxamine to suppress I(Na) near the physiologic cardiac resting potential of -80 mV. The effect of methoxamine with anesthetics appeared to be additive when using a V(H) of -110 mV, a potential where no Na+ channels are in the inactivated state. Methoxamine in the absence and presence of anesthetics significantly shifted the half maximal inactivation voltage in the hyperpolarizing direction but had no effect on steady-state activation. CONCLUSION: The present results show that methoxamine (alpha1-adrenergic stimulation) decreases cardiac Na+ current in a concentration- and voltage-dependent manner. Further, a form of synergistic interaction between methoxamine and inhalational anesthetics, halothane and isoflurane, was observed. This interaction appears to depend on the fraction of Na+ channels in the inactivated state. (Key words: Anesthetics, volatile: halothane; isoflurane; methoxamine. Patch clamp: whole-cell configuration; sodium current; ventricular guinea pig myocytes.)     

Cricket-based robots

This article describes the development of an autonomous hybrid microrobot that uses legs for propulsion and support of the rear half of the body and a pair of wheels for support of the front half. McKibben artificial muscles actuate the legs, and compressed air is generated by an onboard power plant. Control is also onboard in the form of a PIC microcontroller, from Microchip Technology Inc., that controls the actuators through four three-way valves that are each made up of a pair of microelectromechanical system devices. Its motion resembles that of a cricket.     

Leaf Surface Compounds and Oviposition Preference of Turnip Root Fly Delia floralis: The Role of Glucosinolate and Nonglucosinolate Compounds

The role of leaf surface compounds influencing the oviposition of the turnip root fly, Delia floralis, was investigated using bioassays and fractionation of leaf surface extracts from four Brassica genotypes. Polar leaf surface extracts contained between 65 and 175 nM/g leaf equivalent of glucosinolates. However, following fractionation it was found that nonglucosinolates were the major stimuli for D. floralis oviposition. Electrophysiological studies of leaf surface extracts and their fractions were performed by using D. radicum, the cabbage root fly, as an analytical tool. The most behaviorally active fractions contained stimulatory compound(s) that had an activity profile identical to that previously described for recently discovered nonglucosinolate compounds. The role of leaf surface chemicals in influencing antixenotic resistance to D. floralis is discussed.     

Fatty Acids Released from Milk Fat by Lipoprotein Lipase and Lipolytic Psychrotrophs

ABSTRACT: The ability of 13 different strains of psychrotrophs to release free fatty acids in milk was evaluated by using GC analysis. The 13 strains could be categorized into 3 groups: Group 1 consisted of bacteria that grew well and released large quantities of free fatty acids, group 2 consisted of bacteria that grew well but released low amounts of free fatty acids, and group 3 consisted of bacteria that did not grow well nor released large quantities of fatty acids. In group 1, 3 strains were determined to be highly lipolytic, releasing short‐chain fatty acids in amounts greater than reported threshold values. Group 3 consisted of 2 strains, which did not grow well in heat‐treated milk, and the subsequent release of free fatty acids was minor during the 10‐d monitoring time. The other 8 strains tested showed no specific pattern of fatty acid release and quantities of short‐chain fatty acids were not large, despite the ability to grow to high numbers in the treated milk. This work indicates that the lipolytic activity of psychrotrophs common in raw milk is specific to the species and a general prediction of free fatty acid release may not be possible.     

Exposure to environmental and mainstream tobacco smoke and risk of spontaneous abortion

The present nationwide, multicenter clinical study was carried out in 26 departments of surgery to define the incidence and attendant mortality of intestinal infarction following abdominal aortic surgery, and to identify patients at risk of it. The data consist of 1752 patients who underwent abdominal aortic reconstruction during 1991-1993 as recorded in the Finnish national vascular registry (FINNVASC). Among the 1752 operations, 27 patients treated at 14 different hospitals had intestinal ischemia, and the complete patient records of all 27 cases were reanalyzed. The incidence of bowel infarction was 1.2%. Among patients operated on for a ruptured aneurysm it was 3.1%, whereas 1.0% of patients with nonruptured aneurysm and 0.6% of those operated on for aortoiliac occlusive disease developed intestinal infarction. In 14 patients (67%) the lesion affected the left colon. The overall 30-day mortality rate was 13% but reached 67% among those with intestinal infarction. We conclude that acute intestinal ischemia with bowel infarction is an infrequent but serious complication of abdominal aortic surgery. It is mainly related to surgery due to aneurysmal disease, and patients with occlusive aortoiliac disease present ischemic complications in the intestines less often. Hypotensive patients being treated for ruptured aneurysm are at greatest risk of intestinal ischemia.     

Catalytic subunit of DNA-dependent protein kinase: impact on lymphocyte development and tumorigenesis

The DNA-dependent protein kinase (DNA-PK) consists of a heterodimer DNA-binding complex, Ku70 and Ku80, and a large catalytic subunit, DNA-PKcs. To examine the role of DNA-PKcs in lymphocyte development, radiation sensitivity, and tumorigenesis, we disrupted the mouse DNA-PKcs by homologous recombination. DNA-PKcs-null mice exhibit neither growth retardation nor a high frequency of T cell lymphoma development, but show severe immunodeficiency and radiation hypersensitivity. In contrast to the Ku70-/- and Ku80-/- phenotype, DNA-PKcs-null mice are blocked for V(D)J coding but not for signal-end joint formation. Furthermore, inactivation of DNA-PKcs leads to hyperplasia and dysplasia of the intestinal mucosa and production of aberrant crypt foci, suggesting a novel role of DNA-PKcs in tumor suppression.