The cortisol response to psychological stress in temporomandibular dysfunction

Recombinant antibody fragments can be produced in large quantities using bacterial expression systems and could potentially be useful for the generation of biofilters for the selective removal of viral particles from fluids. A human single chain-Fv antibody library, derived from synthetic repertoires of germ line VH-gene segments rearranged in vitro and paired to a single light chain (Nissim et al., 1994, EMBO J., 13, 692-698), has recently been used to isolate hundreds of different binding specificities by panning with antigen. Antibodies from this library typically have affinities in the 10(6)-10(7) M-1 range. Occasionally, better binders are isolated but at other times the affinities recovered are poor. In the latter situation binding cannot be detected with soluble antibodies, but only by high-avidity display of multiple copies of antibodies on phage. By panning with human cytomegalovirus (HCMV)-coated immunotubes, we have isolated a number of antibody clones from this library that bound to the antigen only if displayed on the filamentous phage, but not in soluble form. One of these clones was selected for an affinity maturation procedure, achieved by combinatorial mutagenesis of the complementarity determining region 3 (CDR3) of the antibody light chain, followed by selection of the resulting library for HCMV binding. By this means, we were able to isolate a number of binders, some of which exhibited specific HCMV binding in soluble form. The clone that gave the strongest ELISA signal was expressed in bacteria, purified in solution, characterised using a novel capture methodology with surface plasmon resonance detection on a BIAcore instrument and used for the production of an immunofilter for the removal of HCMV form human serum. The filter removed more than 99% of applied HCMV in 10 min circulation time, while the amount of HCMV retained non-specifically in a cartridge derivatised with a non-specific antibody was less than 10% under similar conditions.     

The stress response in fish

The stress response in teleost fish shows many similarities to that of the terrestrial vertebrates. These concern the principal messengers of the brain-sympathetic-chromaffin cell axis (equivalent of the brain-sympathetic-adrenal medulla axis) and the brain-pituitary-interrenal axis (equivalent of the brain-pituitary-adrenal axis), as well as their functions, involving stimulation of oxygen uptake and transfer, mobilization of energy substrates, reallocation of energy away from growth and reproduction, and mainly suppressive effects on immune functions. There is also growing evidence for intensive interaction between the neuroendocrine system and the immune system in fish. Conspicuous differences, however, are present, and these are primarily related to the aquatic environment of fishes. For example, stressors increase the permeability of the surface epithelia, including the gills, to water and ions, and thus induce systemic hydromineral disturbances. High circulating catecholamine levels as well as structural damage to the gills and perhaps the skin are prime causal factors. This is associated with increased cellular turnover in these organs. In fish, cortisol combines glucocorticoid and mineralocorticoid actions, with the latter being essential for the restoration of hydromineral homeostasis, in concert with hormones such as prolactin (in freshwater) and growth hormone (in seawater). Toxic stressors are part of the stress literature in fish more so than in mammals. This is mainly related to the fact that fish are exposed to aquatic pollutants via the extensive and delicate respiratory surface of the gills and, in seawater, also via drinking. The high bioavailability of many chemicals in water is an additional factor. Together with the variety of highly sensitive perceptive mechanisms in the integument, this may explain why so many pollutants evoke an integrated stress response in fish in addition to their toxic effects at the cell and tissue levels. Exposure to chemicals may also directly compromise the stress response by interfering with specific neuroendocrine control mechanisms. Because hydromineral disturbance is inherent to stress in fish, external factors such as water pH, mineral composition, and ionic calcium levels have a significant impact on stressor intensity. Although the species studied comprise a small and nonrepresentative sample of the almost 20,000 known teleost species, there are many indications that the stress response is variable and flexible in fish, in line with the great diversity of adaptations that enable these animals to live in a large variety of aquatic habitats.     

Long-term effects of prenatal stress and handling on metabolic parameters: relationship to corticosterone secretion response

The prenatal and postnatal environment exerts a long-term influence on the stress-response of the hypothalamic-pituitary-adrenal (HPA) axis. In this study, the long-term effects of prenatal and postnatal manipulations and their related changes on glucocorticoid secretion were examined on metabolic parameters in adult rats. Plasma glucose levels, body weight and basal feeding behavior were measured. We show that modifications of the prenatal and postnatal environment have opposite long-term effects on these parameters, except for blood glucose, which was increased in prenatally stressed animals. Although the mechanisms underlying these phenomena remain to be elucidated, the observations show that perinatal manipulations have long-term effects on metabolic functions related to HPA activity.     

Endocrine response to surgical stress

The similar response is elicited by different surgical stress for the maintenance of homeostasis. The afferent neurogenic stimuli initiate the endocrine response. The production of inflammatory cytokines also stimulates the neuroendocrine system. Activation of the sympathoadrenal, hypothalmo-pituitary-adrenal axis, and renin-angiotensin-aldosterone-axis results in increased serum concentrations of stress hormones. The endocrine alterations provide the optimal hemodynamic, metabolic and immunologic response. Such response to surgical stress is highly complex. However, a better understanding of the mechanisms may lead to improved strategies of the treatment for critical surgical illness. This article focuses on the mechanisms of the neuroendocrine system activation by surgical injury and the role of the response for maintaining homeostasis.     

Structural-functional chromosome organization in response to stress

Published data and the results of experiments conducted at the Laboratory of Genetics of Higher Nervous Activity, Pavlov Institute of Physiology, on the effect of stress on chromosome structure and function are reviewed briefly. Experiments were performed on inbred rats selected for excitation threshold and mutant Drosophila with altered metabolism of secondary mediators.     

Forearm blood flow in response to stress.

Examined the relationship between stress, forearm blood flow, and subjective anxiety. In 26 normal male Ss, electric shocks applied to the opposite forearm led to a rapid rise in anxiety and forearm blood flow. With repeated regular shocks, habituation of the vasomotor response occurred and anxiety became less intense. Changes appeared to be related to S's ability to predict accurately the intensity and frequency of the stimulus. Mental arithmetic under harassment produced a more gradual but greater rise in blood flow without an equal rise in anxiety. 23 alcoholic Ss who were judged to have limited motivation and ego strength showed a significantly lower vasomotor response during mental arithmetic. It is concluded that changes in forearm blood flow observed during stress cannot be related only to an increase in anxiety. This response seems to depend also on the significance of the stimulus to S, his psychiatric status, and his level of motivation. (19 ref.) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Decreased response to phototherapy for neonatal jaundice in breast-fed infants

OBJECTIVE: To evaluate the efficacy of phototherapy for nonhemolytic hyperbilirubinemia in breast-fed and formula-fed infants and infants receiving formula and breast milk. DESIGN: Prospective study. SETTING: Nursery for healthy infants. METHOD: Full-term healthy infants with nonhemolytic hyperbilirubinemia (bilirubin concentration, >255 micromol/L [14.9 mg/dL] or 222 micromol/L [13.0 mg/dL] at ages younger than 48 hours) were treated with conventional phototherapy by using daylight fluorescent lamps. Three groups of infants were studied: group 1, formula-fed infants; group 2, breast-fed infants; and group 3, infants receiving formula and breast milk. All patterns of feeding started at birth. Phototherapy was terminated only when bilirubin concentrations had decreased to less than 185 micromol/L (10.8 mg/dL); the minimum exposure period was 24 hours. RESULTS: A total of 163 infants were studied: group 1, 79; group 2, 34; and group 3, 50. The age at the start of exposure was comparable in all groups. The mean+/-SD weight loss as a percentage of birth weight was as follows: group 1, 2.8%+/-5.0%; group 2, 6.1%+/-3.4%; and group 3, 3.2%+/-2.6%. The duration of exposure to phototherapy was as follows: group 1, 54.1+/-20.8 hours; group 2, 64.6+/-25.1 hours; and group 3, 54.9+/-21.5 hours; the 24-hour rate of decrease in the bilirubin concentration was as follows: group 1, 18.6%+/-11.7%; group 2, 17.1%+/-9.6%; and group 3, 22.9%+/-9.4%. The overall rate of decrease in the bilirubin concentration for the duration of exposure to phototherapy was as follows: group 1, 0.8%+/-0.3% per hour; group 2, 0.6%+/-0.3% per hour; and group 3, 0.8%+/-0.3% per hour. Weight loss at the start of phototherapy was significantly greater in group 2 compared with group 1 (P<.001) and group 3 (P<.001), although the hemoglobin and hematocrit values were comparable. The duration of exposure to phototherapy was not significantly different in the 3 groups (P=.06); however, the duration of exposure of group 2 infants was 10 hours more than that of the other 2 groups. The 24-hour rate of decrease in the bilirubin concentration in group 3 was significantly better than that of group 2 (P = .007) and group 3 (P = .02); the rates of decrease for groups 2 and 3 were similar (P = .52). The overall rate of decrease in the bilirubin concentration during the duration of exposure to phototherapy in group 2 was significantly less than that of group 1 (P = .002) and group 3 (P<.001); the rates for groups 1 and 3 were similar (P = .35). The postexposure rebound bilirubin concentrations were comparable in all groups during the first 2 days; however, the duration of moderate jaundice in group 2 was more prolonged. CONCLUSIONS: The response to phototherapy of group 2 infants was significantly slower than that of group 3 and group 1 infants; this response was still of adequate efficacy. The addition of formula to the feedings for totally breast-fed infants, without suspension of breast-feeding, would enhance the efficacy of phototherapy and reduce exposure time.     

Bisensory response to temporal frequency in 4-month-old infants.

Three studies investigated detection of auditory–visual equivalence of rate among 55 4-mo-olds. In the 1st 2 studies, Ss were shown pairs of check patterns flashing at 2, 4, and 8 Hz either in silence or while listening to a tone corresponding in rate to 1 member of the pair. In Study 1, rate of stimulation varied, whereas duty cycle (i.e., intensity) was kept constant. No evidence of bisensory matching of rate was found. In Study 2, rate and duty cycle covaried. Although no matching was found, the presence of the 2 most intense sounds led to a shift in looking toward lower rates of visual stimulation. In Study 3, rate was kept constant (2 Hz), whereas duty cycle was varied. No matching was found, but as in Study 2, the presence of the most intense sound led to a shift in looking toward the less intense visual stimuli. Although these findings are contrary to previous reports of auditory–visual matching of rate, they do indicate that sound influences visual preferences via an intensity-based response mechanism. (21 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

The stress response of critical illness

The integrated stress response to tissue trauma is crucial for the maintenance of homeostasis. An exaggerated or prolonged response may be detrimental in compromised patients. Knowledge of the involved afferent pathways will suggest therapeutic interventions that may modulate the intensity of the stress response. Described are these concepts as they relate to perioperative medicine.     

Regulation of GLUT1 in response to cellular stress

We assessed the effect of smooth muscle contraction and relaxation on airway lumen subtended by the internal perimeter (Ai) and total cross-sectional area (Ao) of human bronchial explants in the absence of the potential lung tethering forces of alveolar tissue to test the hypothesis that bronchoconstriction results in a comparable change of Ai and Ao. Luminal area (i.e., Ai) and Ao were measured by using computerized videomicrometry, and bronchial wall area was calculated accordingly. Images on videotape were captured; areas were outlined, and data were expressed as internal pixel number by using imaging software. Bronchial rings were dissected in 1.0- to 1.5-mm sections from macroscopically unaffected areas of lungs from patients undergoing resection for carcinoma, placed in microplate wells containing buffered saline, and allowed to equilibrate for 1 h. Baseline, Ao [5.21 +/- 0.354 (SE) mm2], and Ai (0.604 +/- 0.057 mm2) were measured before contraction of the airway smooth muscle (ASM) with carbachol. Mean Ai narrowed by 0.257 +/- 0.052 mm2 in response to 10 microM carbachol (P = 0.001 vs. baseline). Similarly, Ao narrowed by 0.272 +/- 0.110 mm2 in response to carbachol (P = 0.038 vs. baseline; P = 0.849 vs. change in Ai). Similar parallel changes in cross-sectional area for Ai and Ao were observed for relaxation of ASM from inherent tone of other bronchial rings in response to 10 microM isoproterenol. We demonstrate a unique characteristic of human ASM; i.e., both luminal and total cross-sectional area of human airways change similarly on contraction and relaxation in vitro, resulting in a conservation of bronchiolar wall area with bronchoconstriction and dilation.     

Cellular response to a multiple-metal stress in Pseudomonas fluorescens

Pseudomonas fluorescens multiplied in a minimal mineral medium supplemented with millimolar amounts of aluminum (5 mM), iron (5 mM), zinc (3 mM), calcium (2 mM) and gallium (1 mM). A slight decrease in growth rate and a 22% diminution in cellular yield were observed as compared to the control medium. Citrate, the sole source of carbon to which the test metals were complexed, was completely utilized. Although at stationary phase of growth most of the metals were immobilized in an exocellular lipid-rich residue, ultracentrifugation and dialysis studies revealed that metals were associated with phosphatidylethanolamine (PE) from early stages of growth. As growth progressed the metal content of the soluble cellular extract increased reaching an optimum at 35 h of incubation. However, no detectable amounts of metals in this cellular component were discerned at stationary phase of growth. There appeared to be no marked variation in exocellular protein and carbohydrate production in control and metal-stressed cultures. Transmission electron microscopic studies revealed metal rich bodies associated with the cytoplasm. Scanning electron microscopic analyses of the dialyzate aided in the identification of the metal-rich bodies associated with elongated structures comprised of carbon, oxygen and phosphorus. PE appeared to be an important organic constituent of the gelatinous residue.     

2-deoxy-D-glucose-induced metabolic stress enhances resistance to Listeria monocytogenes infection in mice

OBJECTIVE: Bacteria are considered to be important in the pathogenesis of several forms of arthritis. The goal of this study was to apply the 16S ribosomal RNA (rRNA)-polymerase chain reaction method for the detection of bacterial DNA in synovial fluid (SF) and synovial tissue (ST) from inflamed joints. METHODS: Samples from 5 patients with septic arthritis and from 7 with osteoarthritis or arthritis secondary to joint trauma were used as controls. Samples from 6 patients with spondylarthropathy (SpA) and from 20 with undifferentiated arthritis (UA) were analyzed for the presence of bacterial DNA using universal 16S rRNA primers. Automated sequencing and comparative data analysis were performed to identify the species. RESULTS: In the positive control group, the bacterial species cultured from the synovium could be identified in all cases. No bacterial DNA was detected in the SF and ST from patients in the negative control group. In 4 of 6 patients with SpA and 7 of 20 with UA, the analysis of joint samples revealed the presence of bacterial DNA. Sequence analysis indicated the presence of multiple species, which was confirmed by sequencing of cloned products. CONCLUSION: When the the above techniques were used with a stringent regimen, we were able to demonstrate that it is possible to collect and analyze joint samples without contaminating bacterial DNA. The accumulation of phagocytic cells that contain bacterial DNA of various species could play a role in the pathogenesis of both SpA and UA.     

The temporal dynamics of the stress response

This paper summarises the available evidence that failure of defense mechanisms in (semi)-natural social groups of animals may lead to serious forms of stress pathology. Hence the study of social stress may provide animal models with a high face validity. However, most of the animal models of human stress-disorders have concentrated on the consequences of chronic exposure to stressors. The present paper considers recent data, indicating that a single experience with a major stressor in the form of social defeat may have long-term consequences ranging from hours to days and weeks. It seems that the experience of a major stressor sensitizes the animal to subsequent stressors. The consequences of these long-term temporal dynamics of the stress response to the development of stress-related disorders and stress-vulnerability are discussed.     

Protein expression in response to folate stress in Escherichia coli

Interruption of folate metabolism by trimethoprim results in the elevated expression of folate stress proteins in Escherichia coli. E. coli grown in culture medium supplemented with the folate-dependent metabolites glycine, methionine, and the purine nucleoside inosine shows reduced expression of folate stress proteins. The folate stress proteins include the universal stress protein, the ferric uptake regulatory repressor, and possibly, lipoamide dehydrogenase, the L protein component of the glycine cleavage enzyme complex.