Knowledge, practices and perceptions regarding oral health preventive measures among Mexican dental students: a cross-sectional survey study

Although oral diseases are mostly preventable, they remain a global public health problem. Thus, there is a need for trained personnel to actively intervene in promoting oral health, to prevent and timeously detect oral diseases, and, in turn, to provide comprehensive quality healthcare. The main objective of the study was to evaluate the knowledge, practices and perceptions regarding oral health preventive measures amongst undergraduate dental students. This cross-sectional study was conducted between the period October 2017 and January 2018. The subjects included were undergraduate students of the dental science program at the School of Dentistry, in Leon Guanajuato, Mexico. A validated questionnaire was used to identify knowledge of preventive dentistry and the frequency of oral health preventive actions in the dental school clinics. Besides, perception towards prevention in dentistry was assessed. A total of N=232 undergraduate students participated of whom 65.9% (N=153) were women. More than half of the students 59.5%, (N=138) rated their knowledge on the prevention of oral diseases as good, followed by 32.8% (N=75) of students who rated it as regular. 49% (N=97) of the students performed frequently preventive treatments in their daily clinical practice. 90% (N=217) think that the main reason of low practice of prevention in dentistry is the lack of commitment of the dentist. 72.8% (N=169) mention that there should be professionals dedicated exclusively to preventive dentistry. Students of second grade demonstrated better prevention knowledge and tended to engage more frequently in preventive activities (p<0.05). In conclusion, our study found that, second-year students perform preventive practices more frequently and these practices decrease as their studies progress. It should be sought to create positive attitudes towards prevention not only in the year in preventive dentistry, but also throughout the entire career. This enables students to become trained professionals that can deliver preventive services to their patients.

Evaluation of Arthrocentesis with hyaluronic acid injections for management of temporomandibular disorders: a systematic review and case series

Although arthrocentesis is an accepted safe treatment modality for the management of temporomandibular disorders (TMD) in symptomatic patients, the benefit of hyaluronic acid (HA) injections remains uncertain. The aim of this study was to evaluate whether intra-articular HA injections adjunctive to arthrocentesis can be more effective than other medications for the improvement of TMD associated symptoms. Additionally, the impact of HA injections on quality of life of TMD patients was assessed with SF-36® questionnaire in a cohort of patients. An electronic search of Medline, Scopus and Cochrane databases was performed up to March 2020. The following search terms were used: "arthrocentesis", "hyaluronic acid", "intra-articular injections", "visco-supplementation", "temporomandibular disorders". Prospective and retrospective studies that reported the application of HA injections compared to other intra-articular drugs for the treatment of temporomandibular disorders were included. Systematic or narrative reviews and pre-clinical studies were excluded. Additionally, a retrospective clinical study was performed for evaluation of changes in quality of life before and after arthrocentesis with HA injections. In the systematic review, the initial search yielded 1327 articles. After screening of the titles, abstracts, and full texts, 29 studies were selected (26 randomized studies, 2 controlled clinical trials, 1 retrospective report). In the clinical study, 12 patients were included. Intra-articular injections of HA and other medications together with arthrocentesis seemed to be beneficial for improvement of functional symptoms of TMD and pain. The case series also supported the efficacy of HA injections showing an improvement of quality of life of these patients. However, from literature review, it was impossible to identify an optimum drug or a protocol for predictably improving the pain and/or functional symptoms of temporomandibular problems, due to different etiologies, diversity of treatment modalities and conflicting results. In conclusion, there is no consensus in the literature that HA injections shows better results in comparison with other treatment modalities. According to the results of the present clinical study, HA injections with/without arthrocentesis seems to be beneficial in terms of clinical symptoms and quality of life of the TMD patients.

Clinical efficacy of grape seed extract as an adjuvant to scaling and root planing in treatment of periodontal pockets

Grape seed extract (GSE), a naturally producing polyphenolic compound, is found to be a potent hostmodulatory agent and considered for management of periodontal disease. Its anti-bacterial, antioxidant, and anti-inflammatory property may aid in achieving periodontal health. To assess the clinical efficacy of GSE in adjunct to scaling and root planing (SRP) in healing of periodontal pockets. The present study was a longitudinal, parallel design, randomized clinical trial. Seventy-two patients (mean age 39.2±8.6 years) with periodontal pockets were randomly divided into two groups; Test group received intra-pocket delivery of GSE with SRP and Control group received SRP alone. The clinical parameters like Plaque Index (PI), Gingival Index (GI), Probing Depth (PD) and Relative Attachment Level (RAL) were recorded at baseline and 3 months. 64 patients completed the study. Test group at the end of 3 months had statistically significant reduced PD (p=0.002) and RAL (p=0.01). No significant difference was observed for PI and GI at the end of 3 months. Intra-pocket application of GSE with SRP could be beneficial in management of periodontal pockets.

Role of probiotics in adjunct to non-surgical periodontal therapy in patients with chronic periodontitis: a systematic review and meta-analysis

The objective of this study was to establish the significance of probiotic usage, both as a preventive as well as a therapeutic strategy for the management of periodontal disease. It also substantiates the existing studies of single/combined bacterial strain for exhibiting variable ecological impact on oral bacteria. Data sources included literature searches of PubMed (MEDLINE), Scopus, Embase, CENTRAL and Web of science databases for placebo controlled randomized clinical trials of SRP with orally administered probiotics in any form as an adjunct. Data extraction was conducted and information from the included studies was tabulated according to the study designs, form of drug delivery, main outcomes, and clinical parameters. Data collected were based on the focused question outlined for the present systematic review. The reviewers cross-checked all extracted data. CAL and PD were assessed as the primary outcome to compare the effectiveness of adjunctive probiotic therapy in addition to SRP. Fourteen clinical studies were included and demonstrated efficacy in reducing periodontal probing depth (PPD) and gaining clinical attachment level (CAL), between probiotics and SRP/placebo. Adjunctive probiotic therapy in addition to SRP leads to decrease in probing depth and clinical attachment gain in chronic periodontitis patients. However, further high-quality randomized clinical trials with microbiological outcomes are required to fortify the conclusion.

Clinical effectiveness of Lactobacillus reuteri in the treatment of peri-implant diseases: a systematic review and meta-analysis

In the last decades, the presence of peri-implant diseases (PD) has increased. One of the therapies currently used is probiotics with Lactobacillus reuteri (LR). The aim of this article is to determinate, through a systematic review and meta-analysis, the clinical effectiveness of LR in the treatment of PD. We searched the literature until January 2021, in the biomedical databases: Pubmed, Embase, Scielo, Science Direct, Scopus, SIGLE, LILACS, Google Scholar and Cochrane Central Registry of Clinical Trials. The selection criteria of the studies were: randomized controlled clinical trials, without language and time restriction, reporting the clinical effects (depth to probing, plaque index and bleeding index) of the LR in the PD treatment. The risk of study bias was analyzed through the Cochrane tool for randomized studies using Review Manager software. The search strategy resulted in 6 articles of which four investigated peri-implantitis and three peri-implant mucositis. All studies reported that there was a difference in the depth of the probing in the treatment of PD, in favor of the group using LR, though not always achieving significance. The use of LR can be clinically effective in terms of pocket depth reduction in the treatment of PD.

The hydrogen sulphide-releasing derivative of diclofenac protects against ischaemia-reperfusion injury in the isolated rabbit heart

BACKGROUND AND PURPOSE

Hydrogen sulphide (H(2)S) is an endogenous gaseous mediator active in the multilevel regulation of pathophysiological functions in mammalian cardiovascular tissues.

EXPERIMENTAL APPROACH

This study investigated the pharmacological activity of a new H(2)S-releasing derivative of diclofenac, S-diclofenac (2-[(2,6-dichlorophenyl)amino]benzeneacetic acid 4-(3H-1,2-dithiole-3-thione-5-yl)-phenyl ester) in the isolated rabbit heart submitted to low-flow ischaemia-reperfusion damage.

KEY RESULTS

S-diclofenac (3, 10 and 30 microM), despite inhibiting prostacyclin generation by cardiac tissues, achieved dose-dependent normalization of coronary perfusion pressure, reducing left ventricular contracture during ischaemia and improving left ventricular developed pressure and +/-dP/dt(max) at reperfusion. Creatine kinase and lactate dehydrogenase activities in heart perfusates were significantly reduced during reperfusion. These effects were accompanied by substantial release of reduced glutathione (GSH), indicating that the H(2)S moiety may have up-regulated cysteine transport. The anti-ischaemic activities of S-diclofenac and the H(2)S-donor sodium hydro sulphide (NaHS) were partially prevented by the K(ATP) channel antagonist glibenclamide, suggesting a mechanism similar to H(2)S-induced cardioprotection in metabolic ischaemic preconditioning. Perfusion with the nitric oxide (NO) synthase inhibitor N(G)-monomethyl-L-arginine worsened the myocardial ischaemia-reperfusion damage, but this was dose-dependently prevented by S-diclofenac and NaHS, suggesting that the released H(2)S may have overcome NO deficiency.

CONCLUSION AND IMPLICATIONS

These data show that S-diclofenac had marked anti-ischaemic activity in ischaemic-reperfused rabbit hearts despite inhibition of prostaglandin generation. Increased GSH formation leading to activation of K(ATP) channels may have contributed to this beneficial effect. The pharmacological profile of S-diclofenac and its anti-inflammatory activity, with diminished gastrointestinal side effects, offer therapeutic applications in cardiovascular disease.

Sildenafil reduces L-NAME-induced severe hypertension and worsening of myocardial ischaemia-reperfusion damage in the rat

BACKGROUND AND PURPOSE

Phosphodiesterase-5 inhibitors are beneficial in pulmonary hypertension and congestive heart failure, the two conditions associated with coronary heart disease and ischaemia. We investigated whether sildenafil counteracts the cardiovascular alterations induced by N -nitro-L-arginine methyl ester (L-NAME) in the rat.

EXPERIMENTAL APPROACH

Sildenafil was given orally to rats at doses of 0.37, 0.75 or 1.5 mg kg-1day-1 for four weeks, either alone or with L-NAME (35-40 mg kg-1 day-1 in the drinking water). Systolic blood pressure and urinary parameters (6-keto-prostaglandin F1alpha, thromboxane B2, 8-isoprostane-prostaglandin F2 and nitrite/nitrate) were measured in conscious rats. Isolated hearts were subjected to low flow ischaemia-reperfusion, and myocardial levels of guanosine 3', 5'cyclic monophosphate (cGMP) were determined. Endothelial vascular dysfunction was examined in aortic rings.

KEY RESULTS

Sildenafil dose-dependently prevented the rise in systolic blood pressure in L-NAME-treated rats. This activity was associated with a normalization of urinary 8-isoprostane-prostaglandin F2alpha and other biochemical parameters. In perfused hearts, the post-ischaemic ventricular dysfunction was worse in preparations from L-NAME-treated rats than in controls. Sildenafil dose-dependently reduced this effect, and creatine kinase and lactate dehydrogenase release were lower too. cGMP levels, which were low in myocardial tissue from L-NAME-treated rats, were restored by sildenafil. In noradrenaline-precontracted aortic rings from L-NAME-treated rats acetylcholine lost its vasorelaxant effect, and sildenafil restored it.

CONCLUSION AND IMPLICATIONS

In a rat model of chronic nitric oxide deprivation, where hypertension and aggravation of post-ischaemic ventricular dysfunction are associated with loss of vascular endothelium-relaxant function, sildenafil provided significant cardiovascular protection, primarily by maintaining tissue cGMP levels.

Nefopam is more potent than carbamazepine for neuroprotection against veratridine in vitro and has anticonvulsant properties against both electrical and chemical stimulation

Nefopam (NEF) is a known analgesic that has recently been shown to be effective in controlling both neuropathic pain and convulsions in rodents. In this study we compared nefopam to carbamazepine (CBZ), a reference antiepileptic drug (AED), for their ability to protect cerebellar neuronal cultures from neurodegeneration induced by veratridine (VTD). Furthermore, we tested nefopam for protection against both, maximal electroshock-induced seizures (MES), and isoniazid-induced seizures in mice. Both NEF and CBZ were effective in preventing both signs of excitotoxicity and neurodegeneration following exposure of cultures to 5 microM veratridine for 30 min and 24 h, respectively. Concentrations providing full neuroprotection were 500 microM CBZ and 50 microM NEF, while the concentration providing 50% neuroprotection was 200 microM for CBZ and 20 microM for NEF. Neither NEF nor CBZ reduced excitotoxicity following direct exposure of cultures to glutamate, but CBZ failed to reduce increases in intracellular calcium following stimulation of L-type voltage sensitive calcium channels. In vivo, NEF (20 mg/kg i.p.) significantly reduced MES and fully prevented MES-induced terminal clonus (TC). In comparison, NEF was significantly more effective than CBZ in preventing MES, although both drugs were equally effective against MES-induced TC. Furthermore, nefopam provided protection against isoniazid-induced seizures at doses similar to those protecting against MES.

Nefopam, an analogue of orphenadrine, protects against both NMDA receptor-dependent and independent veratridine-induced neurotoxicity

Nefopam hyghochloride is a potent analgesic compound commercialized in most Western Europe for 20 years, which possesses a profile distinct from that of opioids or anti-inflammatory drugs. Previous evidence suggested a central action of nefopam but the detailed mechanisms remain unclear. While, nefopam structure resembles that of orphenadrine, an uncompetitive NMDA receptor antagonist, here we report that differently from orphenadrine, nefopam (100 microM) failed to protect cultured cerebellar neurons from excitotoxicity following direct exposure of neurons to glutamate. Moreover, nefopam failed to displace MK-801 binding to hippocampal membranes. Nefopam effectively prevented NMDA receptor-mediated early appearance (30 min) of toxicity signs induced by the voltage sensitive sodium channel (VSSC) activator veratridine. The later phase (24 h) of neurotoxicity by veratridine occurring independently from NMDA receptor activation, was also prevented by nefopam. Nefopam effect was not mimicked by the GABA receptor agonist muscimol.

Procyanidins from Vitis vinifera seeds display cardioprotection in an experimental model of ischemia-reperfusion damage

Since the early 1970s, increasing evidence has suggested that the consumption of moderate amounts of alcohol is inversely correlated with mortality from myocardial infarction. There is also some evidence that the protective effects of wine might be more pronounced than those of other alcoholic beverages. These observations prompted us to investigate the cardioprotective activity of Vitis vinifera seeds in experimental ischemia-reperfusion injury. An isolated rabbit heart preparation paced electrically was used to evaluate the effects of a highly purified, high molecular weight fraction of oligomeric procyanidins isolated from Vitis vinifera seeds on myocardial reperfusion injury after 40 min of low-flow (1 ml/min) ischemia. Infusion of the heart with 100 or 200 microg/ml procyanidins dose-dependently reduced left ventricular end-diastolic pressure during ischemia, decreased coronary perfusion pressure, improved cardiac mechanical performance upon reperfusion, increased the release of 6-Keto-prostaglandin F1alpha into the perfusate in both the preischemic and the reperfusion periods and suppressed rhythm irregularity. Procyanidins dose-dependently relaxed human internal mammary aortic (IMA) rings (with intact endothelium) precontracted with norepinephrine. This effect was completely abolished in IMA-rings without functional endothelium or when this vascular tissue was pretreated with nitric oxide synthase inhibitor (NG-monomethyl-L-arginine) or with guanylate cyclase inhibitor (1H-[1,2,4]oxadiazolo[4,3-a]quinoxalin-1-one). In conclusion, these results indicate that procyanidins could be of therapeutical potential in cardiovascular diseases. However, further investigations are required for a better definition of the mode of action of these oligomers.

Novel effect of nefopam preventing cGMP increase, oxygen radical formation and neuronal death induced by veratridine

Nefopam hydrochloride is a potent analgesic compound that possesses a profile distinct from that of opiods or anti-inflammatory drugs. Previous evidence suggested a central action of nefopam but the detailed mechanisms remain unclear. Here we have used cultured cerebellar neurons to test the hypothesis that nefopam may modulate voltage sensitive sodium channel (VSSC) activity. Nefopam (100 microM) effectively prevented NMDA receptor-mediated early appearance (30 min) of toxicity signs induced by the VSSC activator veratridine. Delayed neurotoxicity by veratridine occurring independently from NMDA receptor activation, was also prevented by nefopam. In contrast, excitotoxicity following direct exposure of neurons to glutamate was not affected. Neuroprotection by nefopam was dose-dependent. 50% protection was obtained at 57 microM while full neuroprotection was achieved at 75 microM nefopam. Veratridine-induced sodium influx was completely abolished in nefopam-treated neurons. Intracellular cGMP and oxygen radical formation following VSSC stimulation by veratridine were also effectively prevented by nefopam. Our data are consistent with an inhibitory action of nefopam on VSSC and suggest that nefopam may modulate the release of endogenous glutamate following activation of these channels. This novel action of nefopam may be of great interest for the treatment of neurodegenerative disorders involving excessive glutamate release and neurotransmission.

Comparison of endothelium-dependent vasoactivity of internal mammary arteries from hypertensive, hypercholesterolemic, and diabetic patients

BACKGROUND

Endothelium-dependent relaxation is abnormal in a variety of diseased states. Despite the widespread use of the internal mammary artery (IMA) in coronary artery bypass grafting, there is a lack of comparative studies on IMA endothelial-dependent function in patients with major cardiovascular risk factors.

METHODS

An IMA segment from 48 selected patients undergoing coronary artery bypass grafting was harvested intraoperatively and assigned to one of four groups (n = 12): diabetics requiring therapy, hypertensives, hypercholesterolemic, and nondiabetic-normotensive-normocholesterolemic patients. Internal mammary artery specimens were cut into rings and suspended in organ bath chambers, and the isometric tension of vascular tissues was recorded. The IMA rings were (1) precontracted with norepinephrine, and the endothelium-derived relaxation was evaluated by cumulative addition of acetylcholine, (2) contracted with cumulative concentrations of endothelin-1, and (3) contracted with the nitric oxide synthase inhibitor, N(G)-monomethyl-L-arginine. Furthermore, the release of prostacyclin by the IMA rings was directly measured during basal tone conditions and at the end of the various pharmacologic interventions. Histology of IMA rings was randomly performed.

RESULTS

The results obtained in these experiments showed that IMA rings harvested from hypertensive patients have the greatest impairment of endothelium-dependent response to relaxant and contracting stimuli (p < 0.01 versus nondiabetic-normotensive-normocholesterolemic tissues; p < 0.05 versus hypercholesterolemic and diabetic tissues) and prostacyclin release in normal and stimulated conditions. To a lesser extent, hypercholesterolemic and diabetic tissues show similar depression (diabetic > hypercholesterolemic) both of relaxation and prostacyclin production, with respect to nondiabetic-normotensive-normocholesterolemic specimens (p < 0.05). Histology findings (scanning electron microscopy) did not differ in multiple sections from vessel studies.

CONCLUSIONS

Major cardiovascular risk factors affect the endothelium-dependent vasoactive homeostasis of human IMA differently. Depression of relaxation is highest in patients with a history of hypertension. These findings may be pertinent to early and long-term treatment of patients undergoing coronary artery bypass grafting.

The nitroderivative of aspirin, NCX 4016, reduces infarct size caused by myocardial ischemia-reperfusion in the anesthetized rat

NCX 4016, a nitro-ester of aspirin endowed with antithrombotic activity, appears to have clinical potential in treating cardiac complications related to coronary insufficiency. This compound has been shown to improve postischemic ventricular dysfunction and to reduce myocardial infarct size in the rabbit. The cardioprotection conferred by NCX 4016 (10, 30, and 100 mg/kg) and aspirin (ASA, 54 mg/kg) was evaluated in anesthetized rats subjected to 30 min of myocardial ischemia followed by 120 min of reperfusion (MI/R). Drugs were given orally for 5 consecutive days. NCX 4016 displayed remarkable cardioprotection in rats subjected to MI/R as was evident in the reduction of ventricular premature beats and in the incidence of ventricular tachycardia and fibrillation; they were reduced dose dependently and correlated with survival of all rats treated with the higher dose of NCX 4016. In these animals, infarct size was restricted proportionally to the dose of NCX 4016 associated with diminution of both plasma creatine phosphokinase and cardiac myeloperoxidase activities. ASA showed only a minor degree of protection against MI/R damage. Rats treated with N(G)-nitro-L-arginine methyl ester (L-NAME, 10 mg/kg) demonstrated aggravated myocardial damage in terms of arrhythmias, mortality, and infarct size. Supplementation of nitric oxide (NO) with NCX 4016 (100 mg/kg) greatly reduced the worsening effect caused by L-NAME. The beneficial effects of NCX 4016 appear to derive in large part from the NO moiety, which modulates a number of cellular events leading to inflammation, obstruction of the coronary microcirculation, arrhythmias, and myocardial necrosis.

Novel antioxidant agents deriving from molecular combinations of vitamins C and E analogues: 3,4-dihydroxy-5(R)

Molecular combinations of two antioxidants (i.e., ascorbic acid and the pharmacophore of alpha-tocopherol), namely the 2,3-dihydroxy-2,3-enono-1,4-lactone and the chromane residues, have been designed and tested for their radical scavenging activities. When evaluated for their capability to inhibit malondialdehyde (MDA) production in rat liver microsomal membranes, the 3,4-dihydroxy-5R-2(R,S)-(6-hydroxy-2,5,7,8-tetramethylchroman-2(R,S)yl-methyl)-1,3]dioxolan-4S-yl]-5H-furan-2-one (11a-d), exhibited an interesting activity. In particular the 5R,2R,2R,4S and 5R,2R,2S,4S isomers (11c,d) displayed a potent antioxidant effect compared to the respective synthetic alpha-tocopherol analogue (5) and natural alpha-tocopherol or ascorbic acid, used alone or in combination. Moreover, the mixture of stereoisomers 11a-d also proved to be effective in preventing damage induced by reperfusion on isolated rabbit heart, in particular at the higher concentration of 300 microM. In view of these results our study represents a new approach to potential therapeutic agents for applications in pathological events in which a free radical damage is involved. Design, synthesis and preliminary biological activity are discussed.

The effects of tramadol and morphine on immune responses and pain after surgery in cancer patients

There has been growing interest in determining the possible immune consequences of opioid administration for the management of postoperative pain. We studied the effects of morphine and tramadol on pain and immune function during the postoperative period in 30 patients undergoing abdominal surgery for uterine carcinoma. Phytohemoagglutinin-induced T lymphocyte proliferation and natural killer cell activity were evaluated immediately before and after surgery, and 2 h after the acute administration of either 10 mg of morphine IM or 100 mg tramadol IM for pain. In all patients, phytohemagglutinin-induced lymphoproliferation was significantly depressed by surgical stress. However, in the morphine-treated group, proliferative values remained lower than basal levels for 2 h after treatment, whereas in tramadol-administered patients proliferative values returned to basal levels. Natural killer cell activity was not significantly affected by surgery nor by morphine administration, whereas tramadol significantly enhanced the activity of natural killer cells. Both drugs produced a comparable reduction in postoperative pain. We conclude that, as previously observed in the experimental animal, tramadol and morphine, when administered in analgesic doses, induce different immune effects.

IMPLICATIONS

Recent studies suggest that opioids can have an adverse impact on the immune system. Because surgical stress also induces immune dysfunction, the search for analgesic drugs devoid of immunosuppressive effects is of import. This study compared the effects on immune responses of morphine and of the atypical opioid analgesic, tramadol, given for postoperative pain to gynecological cancer patients. Tramadol and morphine showed comparable analgesic activity; however, tramadol, in contrast to morphine, induced an improvement of postoperative immunosuppression and, therefore, may be preferred to morphine for the treatment of postoperative pain.

The opioid antagonist naloxone induces a shift from type 2 to type 1 cytokine pattern in BALB/cJ mice

Opioid peptides affect different immune functions. We present evidence that these effects could be mediated by the modulation of T(H)1/T(H)2 cytokine production. BALB/cJ mice were immunized with 50 or 100 microg of the protein antigen keyhole-limpet hemocyanin (KLH), and treated acutely or chronically with the opioid antagonist naloxone. One and 2 weeks after immunization, the production of cytokines by splenocytes was evaluated by in vitro restimulation with KLH. The acute and chronic treatment with the opioid receptor antagonist naloxone decreased the production of interleukin (IL)-4 by splenocytes of BALB/cJ mice. In contrast, IL-2 and interferon-gamma levels increased after naloxone treatment. Finally, the opioid antagonist diminished the serum immunoglobulin G anti-KLH antibody titers. These results suggest that naloxone increases T(H)1 and decreases T(H)2 cytokine production. The effect of naloxone could be ascribed to the removal of the regulatory effects exerted by endogenous opioid peptides, which could therefore activate T(H)2 and suppress T(H)1 cytokines. (Blood. 2000;95:2031-2036)

Chronic administration of UK-114, a multifunctional emerging protein, modulates the Th1/Th2 cytokine pattern and experimental autoimmune diseases

UK-114 is a 14-kDa ubiquitous protein recently sequenced by several groups throughout the world. Its activity ranges from being a tumor antigen, a protein synthesis inhibitor or a specific mu-calpain activator. UK-114 shows structural homologies also with proteins of the MHC-1 binding proteins, and heat shock proteins (HSPs). We investigated the possible effects of UK-114 on T helper cells cytokine profile and the development and progression of experimental autoimmune diseases. Homogeneous recombinant UK-114 was used in all experiments. Treatment of Balb/c male mice for two weeks resulted in the increase of IL-4, and the decrease of TNF-alpha, IFN-gamma, and IL-2 release from stimulated splenocytes, suggesting that UK-114 modulates the Th1/Th2 cytokine profile toward Th2. Similar to that observed with HSP60/65, a single pretreatment of Lewis rats with UK-114 significantly blunted the development of adjuvant-induced arthritis, whereas chronic treatment of 4-week-old female NOD mice dose dependently inhibited the development of diabetes.

Bacterial growth in space flight: logistic growth curve parameters for Escherichia coli and Bacillus subtilis

Previous investigations have reported that bacterial suspension cultures grow to higher stationary concentrations in space flight than on Earth; however, none of these investigations included extensive ground controls under varied inertial conditions. This study includes extensive controls and cell-growth data taken at several times during lag phase, log phase, and stationary phase of Escherichia coli and Bacillus subtilis. The Marquardt-Levenberg, least-squares fitting algorithm was used to calculate kinetic growth parameters from the logistic bacterial growth equations for space-flight and control growth curves. Space-flight cultures grew to higher stationary-phase concentrations and had shorter lag-phase durations. Also, evidence was found for increased exponential growth rate in space.

Effects of space flight and mixing on bacterial growth in low volume cultures

Previous investigations have shown that liquid suspension bacterial cultures grow to higher cell concentrations in spaceflight than on Earth. None of these studies included ground-control experiments designed to evaluate the fluid effects potentially responsible for the reported increases. Therefore, the emphasis of this research was to both confirm differences in final cell concentration between 1g and microgravity cultures, and to examine the effects of mixing as a partial explanation for this difference. Flight experiments were performed in the Fluid Processing Apparatus (FPA), aboard Space Shuttle Missions STS-63 and STS-69, with simultaneous 1g static and agitated controls. Additional static 1g, agitated, and clino-rotated controls were performed in 9-ml culture tubes. This research revealed that both E. coli and B. subtilis samples cultured in space flight grew to higher final cell densities (120-345% increase) than simultaneous static 1g controls. The final cell concentration of E. coli cells cultured under agitation was 43% higher than in static 1g cultures and was 102% higher with clino-rotation. However, for B. subtilis cultures grown while being agitated on a shaker or clino-rotated, the final cell concentrations were nearly identical to those of the simultaneous static 1g controls. Therefore, these data suggest that the unique fluid quiescence in the microgravity environment (lack of sedimentation, creating unique transfer of nutrients and waste products), was responsible for the enhanced bacterial proliferation reported in this and other studies.

Immune function alterations in mice tolerant to delta9-tetrahydrocannabinol: functional and biochemical parameters

We studied the effect of acute (1 h) or chronic exposure (7 and 14 days) to delta9-tetrahydrocannabinol (delta9-THC) on immune parameters in male Swiss mice. One hour after a dose of 10 mg/kg s.c., the splenocyte proliferative response to ConA and NK activity were not inhibited, but there was a significant decrease in the production of IL-2. After 7 days of treatment, when mice were tolerant to delta9-THC-induced analgesia, these functional parameters were strongly inhibited and there was a persistent reduction in IL-2 and IFNgamma. With 14 days exposure to the drug, splenocyte proliferation was significantly reduced only with 5 microg/ml ConA, and NK activity was still significantly depressed (about 37%). IL-2 had returned to the control value, whereas IFNgamma was still 40% down. Flow cytometry analysis of spleen cell composition indicated no changes after the acute and 7 day treatments, but at 14 days there was a 20% decrease in the number of T lymphocytes, mirrored by a 26% increase of B lymphocytes. In conclusion, in vivo exposure to psychoactive doses of delta9-THC has profound effects on immune function. This implies some important questions in relation to the liberalization of marijuana and its therapeutic uses.

IL-6 knock-out mice show modified basal immune functions, but normal immune responses to stress

To better determine the role of interleukin-6 in the mechanisms that regulate stress-induced immunosuppression, we used in this study an interleukin-6-deficient mice model recently generated by gene targeting. We report here that, in basal conditions, mutant mice are characterized by altered immune functions. Natural killer activity and interleukin-2 production are lower in splenocytes of interleukin-6 deficient mice compared to those of controls, whereas Concanavalin A-induced splenocyte proliferation is comparable with that observed in wild-type mice. Moreover, splenocyte concentrations of the immunosuppressive opioid peptide beta-endorphin are higher in interleukin-6 deficient mice while serum corticosterone concentrations are unchanged. After exposure to 16 h of restraint stress, a significant suppression of the immune parameters is exhibited and a significant increase of splenocyte beta-endorphin concentrations are present in knock-out and normal animals. Finally, corticosterone is normally induced in stressed interleukin-6-deficient mice, thus demonstrating that interleukin-6 is not crucial for the activation of the hypothalamic-pituitary-adrenal axis. In conclusion, our results indicate that interleukin-6 is not a key factor in the immunosuppression observed after restraint stress.

Endogenous opioids modulate allograft rejection time in mice: possible relation with Th1/Th2 cytokines

The continuous infusion of the opioid peptide beta-endorphin prolongs skin allograft survival in mice, while the opiate receptor antagonist naloxone, administered together with the opioid at the time of transplantation, abolishes the effect of the opioid. Consistently, naloxone, when given alone at the time of transplantation, but not later, accelerates graft rejection and increases splenocyte IL-2 and interferon-gamma (IFN-gamma) production. Splenocyte beta-endorphin concentrations are lower in transplanted animals. The effects of exogenous beta-endorphin and naloxone suggest that the endogenous opioid peptide beta-endorphin exerts a tonic inhibitory effect over early events of T cell-mediated immune responses in vivo. The effects of beta-endorphin and naloxone are consistent with the previously shown role of the opioid system in the modulation of the Th1/Th2 cytokine pattern.

Cellular responses to gravity: extracellular, intracellular and in-between

Our understanding of gravitational effects (inertial effects in the vicinity of 1 x g) on cells has matured to a stage at which it is possible to define, on the basis of experimental evidence, extracellular effects on small cells and intracellular effects on eukaryotic gravisensing cells. Yet undetermined is the nature of response, if any, of those classes of cells that are not governed solely by extracellular physical events (as are prokaryotes) and are devoid of obvious mechanical devices for sensing inertial forces (such as those possessed by certain plant cells and sensory cells of animals). This "in-between" class of cells needs to be understood on the basis of the combination of intracellular and extracellular gravity-dependent processes that govern experimentally-measurable variables that are relevant to the cell's responses to modified inertial forces. The forces that certain cell types generate or respond to are therefore compared to those imposed by approximately 1 x g in the context of cytoskeletal action and symmetry-breaking pathways.

Intermittent but not continuous inescapable footshock stress and intracerebroventricular interleukin-1 similarly affect immune responses and immunocyte beta-endorphin concentrations in the rat

Both CNS- and immunocyte(lymphocytes, splenocytes)-derived beta-endorphin is involved in immune responses to stress. We show in the rat that stress-induced immunodepression (decrease of mitogen-induced lymphocyte proliferation and NK activity) is present only after the administration of a stress paradigm that increases immunocyte-derived beta-endorphin, while this is absent when the concentrations of the opioid are not modified. Interestingly, plasma corticosterone levels were similarly elevated after stresses whether or not they suppress immune responses, thus suggesting a pivotal role of the opioid. The increase of immunocyte beta-endorphin and immunosuppression are similarly present also after the intracerebroventricular administration of interleukin 1, thus suggesting a role for this cytokine in stress responses. The modifications of immunocyte beta-endorphin concentrations and immune responses induced by stress and interleukin 1 are not affected by indomethacin, adrenalectomy or hypophysectomy, whereas they are completely blocked by a CRH antagonist and depletion of the serotoninergic or catecholaminergic systems. In conclusion, our results suggest that immune responses to stress are not uniquely linked to an activation of the HPA axis.

Regulation of immune functions in rat splenocytes after acute and chronic in vivo treatment with CP-55,940, a synthetic cannabinoid compound

Changes in mitogen-induced splenocyte proliferation and NK activity were evaluated after acute (1 h) and chronic (6 d) in vivo treatment of rats with the synthetic cannabinoid compound CP-55,940. At a dose of 0.4 mg/kg i.p. it significantly inhibited the splenocyte proliferative response to PHA and NK activity but half this dose (0.2 mg/kg) had no effect on immune responses. Pretreatment of rats with the cannabinoid receptor CB1 antagonist SR141716A did not antagonize the CP-55,940-induced immunosuppression, excluding the activation of this receptor subtype in the mediation of this effect. When immune function studies were done on rats tolerant to CP-55,940-induced analgesia, full tolerance also developed for the inhibition of splenocyte proliferation and NK activity. The data provided indicate that CB1 cannabinoid receptors are not involved in mediating the acute and chronic effects of cannabinoids on the immune system and suggest a possible implication of CB2 receptor although other modalities of CP-55,940 action can not be ruled out.

Effects of tramadol on immune responses and nociceptive thresholds in mice

Tramadol is a centrally acting analgesic drug with a dual mechanism of action: binding to mu-opioid receptors and potentiation of the monoaminergic systems. In this study, we evaluated the effects of the acute and chronic administration of tramadol on nociceptive thresholds (by the hot-plate test) and on immune responses (by measuring Concanavalin A-induced splenocyte proliferation, IL-2 production and natural killer activity) in the mouse. After acute subcutaneous administration, tramadol induced antinociception starting from a dose of 20 mg/kg, whereas it significantly enhanced natural killer activity and IL-2 production at doses as low as 1 mg/kg and splenocyte proliferation starting from a dose of 10 mg/kg. After the chronic administration, the antinociceptive effect of the drug was still present, whereas the immune modifications disappeared. Thus, the pharmacological profile of tramadol is totally different from that of other drugs which bind mu-opioid receptors. Our results suggest that tramadol could be a good choice for the treatment of pain in patients where immunosuppression may be particularly contraindicated.

Antinociceptive and immunosuppressive effects of opiate drugs: a structure-related activity study

1. Although it is well known that morphine induces significant immunosuppression, the potential immunosuppressive activity of morphine derived drugs commonly used in the treatment of pain (codeine, hydromorphone, oxycodone) has never been evaluated. 2. We evaluated in the mouse the effect of the natural opiates (morphine and codeine) and synthetic derivatives (hydromorphone, oxycodone, nalorphine, naloxone and naltrexone) on antinociceptive thresholds and immune parameters (splenocyte proliferation, Natural Killer (NK) cell activity and interleukin-2 (IL-2) production). 3. Morphine displayed a potent immunosuppressive effect that was not dose-related to the antinociceptive effect, codeine possessed a weak antinociceptive effect and limited immunosuppressive activity; nalorphine, a mu-antagonist and kappa-agonist, exerted a potent immunosuppressive effect, but had very weak antinociceptive activity. The pure kappa-antagonist nor-BNI antagonized the antinociceptive, but not the immunosuppressive effect of nalorphine. 4. Hydromorphone and oxycodone, potent antinociceptive drugs, were devoid of immunosuppressive effects. 5. The pure antagonists naloxone and naltrexone potentiated immune responses. 6. Our data indicate that the C6 carbonyl substitution, together with the presence of a C7-8 single bond potentiates the antinociceptive effect, but abolishes immunosuppression (hydromorphone and oxycodone). 7. The single substitution of an allyl on the piperidinic ring resulted in a molecule that antagonized the antinociceptive effect but maintained the immunosuppressive effect. 8. Molecules that carry modifications of C6, the C7-8 bond and C14, together with an allyl or caboxymethyl group on the piperidinic ring antagonized both the antinociceptive and the immunosuppressive effect of opiates and were themselves immunostimulants.

Centrally injected nerve growth factor modulates peripheral immune responses in the rat

The effect of the intracerebroventricular (icv) and intravenous (iv) injection of nerve growth factor (NGF) on peripheral immunity was studied in the rat. Icv administration of NGF (5, 25, 50, 250 and 500 ng/rat) significantly enhanced phytohemagglutinin (PHA)-induced splenocyte proliferation 30 min after treatment. Icv pretreatment with an anti-NGF antibody completely prevented the effect, while iv injection of anti-NGF antibody did not block the effect of icv NGF. On the contrary, NGF at doses of 0.5, 2.5, 5, 25 and 50 ng/rat decreased splenocyte natural killer (NK) activity. When injected iv, NGF enhanced splenocyte proliferation only at doses of 50 and 500 ng/rat, while it did not affect NK activity. These effects on immunity do not appear mediated by activation of the hypothalamus-pituitary-adrenal axis, since NGF did not modify plasma corticosterone concentrations at the doses used. These results indicate that NGF participates in the complex network of neuroimmune interactions.

Peripheral mononeuropathy affects hypothalamic and splenocyte beta-endorphin levels but not immune function in the rat

Beta-endorphin and substance P levels were measured in the hypothalamus of rats 14 days after chronic constriction injury of right sciatic nerve. Furthermore, beta-endorphin concentrations in splenocytes, phytoemoagglutinin-induced proliferation of splenocytes, and natural killer activity were assessed. We observed a significant increase of beta-endorphin and substance P hypothalamic levels, and a significant decrease of beta-endorphin concentrations in the immune cells. In contrast, the peripheral mononeuropathy did not affect the immune function. This study presents a picture of central and peripheral peptide changes consistent with a painful condition, but different from what previously observed in rats which underwent peripheral nerve deafferentation or stressful conditions.

T-lymphocyte concentrations of cholecystokinin-8 and beta-endorphin in eating disorders: II. Bulimia nervosa

Concentrations of cholecystokinin-8 (CCK-8) and beta-endorphin (beta-EP) in T-lymphocytes of 26 women with bulimia nervosa (BN) and in 26 age- and sex-matched healthy comparison subjects were measured. Ten patients were then treated with 300 mg/day of fluvoxamine, p.o., and five patients were treated with 300 mg/day of amineptine, p.o., for 4 months. Concentrations of the two peptides were measured again after 1, 2, and 4 months of therapy. Basal CCK-8 values were significantly lower in patients than in healthy subjects. During fluvoxamine therapy, CCK-8 values increased, reaching normal levels by month 4 of treatment. No such increase occurred during amineptine therapy. Baseline beta-EP values were normal in the bulimic patients but had declined by month 4 of fluvoxamine therapy.

T-lymphocyte cholecystokinin-8 and beta-endorphin concentrations in eating disorders: I. Anorexia nervosa

Baseline concentrations of cholecystokinin-8 (CCK-8) and beta-endorphin (beta-EP) were measured in T-lymphocytes from 33 restricting patients with anorexia nervosa (AN-R), 23 binging/purging patients with anorexia nervosa (AN-BP), and 24 healthy volunteers. CCK-8 basal values were significantly lower and beta-EP values significantly higher in AN-R and AN-BP patients than in normal volunteers. Levels of the peptides were measured three more times during a 4-month combined cognitive-behavioral/psychopharmacological treatment (nortriptyline or fluoxetine in AN-R, fluoxetine or amineptine in AN-BP). CCK-8 values fluctuated (nonsignificantly) during each treatment, while beta-EP values decreased (to a significant degree only in fluoxetine-treated AN-R patients).

Plasma and synovial fluid interleukin-1, interleukin-6 and substance P concentrations in rheumatoid arthritis patients: effect of the nonsteroidal anti inflammatory drugs indomethacin, diclofenac and naproxen

We performed an open, between patients, placebo controlled study in order to evaluate the effect of the treatment with the non steroidal anti inflammatory drugs indomethacin, diclofenac and naproxen on the concentrations of the cytokines IL-1 beta and IL-6 and of the neuropeptide substance P in plasma and synovial fluid of 24 rheumatoid arthritis patients. All patients had high synovial fluid cytokine and substance P levels, and high plasma cytokine levels at the beginning of the study. The treatment with the non steroidal anti inflammatory drugs significantly decreased both plasma and synovial fluid IL-6 and synovial fluid substance P in comparison to placebo, but did not affect IL-1 beta concentrations. This effect can participate in the therapeutic effect of non steroidal anti inflammatory drugs in rheumatoid arthritis.

Mitogen-induced lymphocyte proliferation and peripheral blood mononuclear cell beta-endorphin concentrations in primary dysmenorrhoea

Dysmenorrhoea is a recurrent painful disease which causes physical and psychological stress. The purpose of the present study was to investigate whether there was a measurable derangement of immune cells and immune responses in women with severe primary dysmenorrhoea. On day 26 of one cycle and on days 1 and 3 of the following cycle we measured polyclonal, mitogen-induced lymphocyte proliferation and beta-endorphin concentration in peripheral blood mononuclear cells obtained from 16 infertile women with normal pelvis, of whom eight had and eight did not have the disorder. In women with dysmenorrhoea, polyclonal mitogen-induced lymphocyte proliferation was lower than in controls on all 3 days considered, but the difference was statistically significant only on day 26 (43,605 +/- 9876 micrograms/ml versus 67,305 +/- 15,249 micrograms/ml; P < 0.01). Monocyte beta-endorphin concentrations in the patients with dysmenorrhoea were significantly elevated on day 3 compared to controls (67.8 +/- 24.3 pg/10(6) cells versus 29.7 +/- 6.9 pg/10(6) cells; P < 0.05). Our results demonstrate that immune responses are modified in patients with primary dysmenorrhoea. These effects are independent of circulating hormone concentrations and are consistent with the role of dysmenorrhoea as a stressful event.

The beta-endorphin inhibition of mitogen-induced splenocytes proliferation is mediated by central and peripheral paracrine/autocrine effects of the opioid

In this study we show that the opioid peptide beta-endorphin exerts a tonic inhibitory effect on the proliferative response of splenocytes to the polyclonal mitogen phytohemoagglutinin throughout two separate sites of action: one central and one peripheral. The intracerebroventricular administration of beta-endorphin, in fact, induces a significant inhibition of splenocyte proliferation. In contrast, both the intracerebroventricular and the peripheral administration of anti-beta-endorphin gamma globulins induce a significant increase in proliferation. Moreover, an increase of splenocyte proliferation was observed also after the intravenous administration of gamma globulins and intraperitoneal naloxone, and this effect was still present in hypophysectomized rats. The data reported suggest that beta-endorphin exerts a tonic inhibitory effect on proliferation, acting centrally, and peripherally throughout a paracrine/autocrine mechanism. FACS experiments show that the effect observed is not the consequence of an alteration of lymphocyte trafficking induced by the opioid.