The Effect of Stress and Meditation on Salivary Protein and Bacteria: A Review and Pilot Study

Abstract

Dentally-induced stress and relaxation-induced anxiety reduction have been correlated with salivary changes in dental patients in two recent studies. In two subsequent studies, test anxiety-induced stress and relaxation-induced anxiety reduction were correlated with salivary changes in dental students. In another study using the resazurin dye indicator, increased salivary bacterial levels were correlated with an increased dental caries incidence. As a result of these findings, it was decided to reinvestigate the effects of stress and relaxation on salivary changes and in addition to examine the effects of those conditions on salivary bacteria. The hypotheses under consideration were: (1) Salivary changes from stress to relaxation will be from opaque to translucent and from high to low protein levels; and (2) salivary bacteria will increase under the condition of stress and decrease under the condition of relaxation. The subjects were twelve dental students. Stress and relaxation were evaluated before and after meditation by verbal reports and examination of saliva for opacity, translucency, protein and bacteria (resazurin dye method). There were significant anxiety-reduction changes by the end of the meditation sessions (p < 0.001) as measured by increased salivary translucency, decreased salivary protein and reduced subjective evaluation of stress. Using the resazurin dye method, bacterial levels showed a significant decrease by the end of the meditation sessions (p < 0.001). The results support hypothesis 1 and reaffirm previous findings in regard to the effectiveness of: (1) salivary changes as measures of stress and relaxation; and (2) meditation to induce deep relaxation. The finding of high bacteria levels under stress and lower bacterial levels under relaxation supports hypothesis 2 and indicates that stress may contribute to dental caries and relaxation may have an anti-caries effect.     

Prenatal maternal stress is associated with delivery analgesia and unplanned cesareans

We tested the hypothesis that women with greater prenatal maternal stress (PNMS) would be more likely to receive intravenous opiates and epidural for delivery, and thereby increase the likelihood of unplanned cesarean delivery. PNMS was assessed during early, mid, and late pregnancy using psychometrically sound instruments in structured interviews with women receiving prenatal care at a public university clinic. Medical records were abstracted for analgesia during delivery, fetal heart tracing (FHT) abnormalities, and method of delivery. Only subjects attempting vaginal delivery (N = 298) were included. Using structural equation modeling, a PNMS variable was constructed from five indicators: pregnancy-specific distress, number of prenatal stressful life events, distress from life events, state anxiety, and perceived stress. After controlling for medical predictors of analgesia receipt and surgical delivery, women with higher PNMS were more likely to receive analgesia, and those who received analgesia were more likely to deliver surgically. Analgesia was also associated with FHT abnormalities, which in turn was associated with surgical delivery (all p's < 0.05). Women who received both an epidural and meperidine were most likely to have a cesarean delivery; 29% of this group delivered surgically. Results indicate that PNMS contributes to higher likelihood of unplanned cesarean delivery through its association with delivery analgesia.     

Nitric oxide—mediated renal epithelial cell injury during hypoxia and reoxygenation

The potent endothelial-derived vasodilator nitric oxide (NO) has been identified as a protective agent in acute renal failure. However, some recent studies have suggested a detrimental effect of NO on rat proximal tubules exposed to hypoxia and reoxygenation. We determined whether NO metabolites cause intracellular oxidation during hypoxia and reoxygenation and whether this oxidative stress is linked to irreversible cell injury. Primary cultures of rat proximal tubular epithelial cells were studied in a subconfluent stage and subjected to 60 min hypoxia and 30 min reoxygenation. Intracellular oxidation was assessed by monitoring the conversion of nonfluorescent dihydrorhodamine 123 (DHR) to fluorescent rhodamine 123 as a probe for the long-lived oxidant peroxvnitrite. Hypoxia and reoxygenation produced a marked increase in cellular generation of oxidant species. Intracellular oxidation of DHR was reduced by approsimately 40% when cells were also exposed to the NO svnthase inhibitor L-NAME. Oxidation of DHR following hypoxia and reoxygenation was not affected by SOD or DATTU. A combination of SOD and L-NAME was no more effective than L-NAME alone. Hypoxia and reoxygenation produced substantial injury (as LDH release). There was a 40% reduction in LDH release when cells were pretreated with a NO synthase inhibitor. In summary, increased generation of NO capable of inducing intracellular oxidizing reactions and cell death occurred during renal hypoxia and reoxygenation.     

Male subfertility as a chronic illness: the role of adaptive challenges

Male factor infertility (MFI) is extremely common, often with several associated chronic health conditions. Because a man’s fertility assessment may be their first contact with health services, the health care team has a responsibility to act as male health advocates to ensure comprehensive care. The diagnosis of subfertility allows a broader view of these men as patients with a chronic illness who have complex health needs. Because of the associated complexity of care following evaluation, there needs to be new approach in how men affected by MFI should be managed long term. In this commentary, we propose that the Adaptive Leadership Framework model for Chronic Illness is a suitable vehicle to use for management of the MFI patient’s journey towards optimized health.     

Protective effects of exogenous gangliosides on ROS-induced changes in human spermatozoa

This article summarizes the available evidence on the efficacy of gangliosides to reduce the degree of reactive oxygen species (ROS)-mediated damage. The antioxidative efficacy of exogenous gangliosides in protecting different cells encouraged us to examine their ability to protect human spermatozoa. Gangliosides are sialic acid-containing glycosphingolipids with strong amphiphilic character due to the bulky headgroup made of several sugar rings with sialic acid residues and the double-tailed hydrophobic lipid moiety. The amphiphilicity of gangliosides allows them to exist as micelles in aqueous media when they are present at a concentration above their critical micellar concentration. The protective effect of ganglioside micelles on spermatozoa is believed to stem from their ability to scavenge free radicals and prevent their damaging effects. In our study, we particularly focused our attention on the protective effect of ganglioside micelles on DNA in human spermatozoa exposed to cryopreservation. The results indicate that ganglioside micelles can modulate the hydrophobic properties of the sperm membrane to increase tolerance to DNA fragmentation, thus protecting the DNA from cryopreservation-induced damage. Further actions of ganglioside micelles, which were documented by biochemical and biophysical studies, included (i) the modulation of superoxide anion generation by increasing the diffusion barrier for membrane events responsible for signal translocation to the interior of the cell; (ii) the inhibition of iron-catalysed hydroxyl radical formation due to the iron chelation potential of gangliosides; and (iii) inhibition of hydrogen peroxide diffusion across the sperm membrane.     

龟鹿二仙胶对糖尿病大鼠生殖损伤的保护作用及机制

目的 探索龟鹿二仙胶改善糖尿病大鼠生殖损伤的疗效及可能作用机制。方法 将53只SD雄鼠随机分成5组，选取其中1组作为正常组，剩余4组合并成造模组用高脂饲料喂养联合30 mg·kg^-1链脲佐菌素（STZ）腹腔注射建立糖尿病模型，以连续3次随机血糖均>16.7 mmol·L^-1作为纳入糖尿病生殖损伤模型标准。将成模的大鼠按血糖高低随机分成模型组、龟鹿二仙胶组（2 g·kg^-1）、维生素E组（0.03 g·kg^-1）、五子衍宗丸组（0.6 g·kg^-1），给予相应药物剂量灌胃，每天1次，连续治疗4周，每周测体质量和血糖。4周后取材进行指标检测，苏木素-伊红（HE）染色观察睾丸及附睾组织形态学变化，原位末端标记法（TUNEL）染色观察睾丸细胞凋亡情况；精液分析仪检测精子浓度和精子活力；酶联免疫吸附测定法（ELISA）检测血清卵泡刺激素（FSH）、黄体生成素（LH）、睾酮（T）水平；ELISA检测睾丸组织超氧化物歧化酶（SOD）、丙二醇（MDA）、活性氧（ROS）、谷胱甘肽过氧化物酶（GSH-Px）含量；蛋白免疫印迹法（Western blot）检测睾丸组织Nrf2、HO-1、Bax、Bcl-2蛋白表达。结果 与正常组比较，模型组大鼠睾丸组织萎缩，生精小管数量减少，附睾管壁增生，管腔狭窄；精子浓度和活力下降（P<0.01）；血清T、FSH和LH水平降低（P<0.01）；睾丸中ROS和MDA含量增加（P<0.01），SOD和GSH-Px水平减少（P<0.01）；Bax表达增加（P<0.01），Nrf2、HO-1、Bcl-2表达降低（P<0.01）。与模型组比较，龟鹿二仙胶组睾丸及附睾组织病变得到一定改善；精子浓度和活力提升（P<0.05，P<0.01）；血清T和LH含量上升（P<0.05，P<0.01），FSH含量差异无统计学意义；睾丸中ROS和MDA含量降低（P<0.01），SOD和GSH-Px水平增加（P<0.01）；Bax表达下降（P<0.01），Nrf2、HO-1、Bcl-2表达上升（P<0.05，P<0.01）。结论 龟鹿二仙胶能在一定程度上改善糖尿病大鼠生殖损伤，提升精子质量，其机制可能与改善氧化应激，抗凋亡作用有关。     

Persistent Behavioural Changes in Rats Following Inescapable Shock Stress: a Potential Model of Posttraumatic Stress Disorder

Behavioural changes in rats two weeks after inescapable shock stress were studied using a shuttle-box task (active avoidance/escape). Rats exposed to inescapable shock stress two weeks beforehand showed more frequent avoidance responses and greater within-group variation in both avoidance response and general activity during the test than rats in a control group. General activity during an unstressful period (before starting the test) did not differ significantly between groups. This relatively prolonged increase in responsiveness to external stimuli in the stressful context may be a useful experimental model of posttraumatic stress disorder, especially in relation to hypervigilance.