Tissue-based class control: the other side of tolerance

In this Essay, we offer a new perspective on how immune responses are regulated. We do not cover how they are turned on and off, but focus instead on the second major aspect of an immune response: the control of effector class. Although it is generally thought that the class of an immune response is tailored to fit the invading pathogen, we suggest here that it is primarily tailored to fit the tissue in which the response occurs. To this end, we cover such topics as the nature of T helper (T(H)) cell subsets (current and yet to be discovered), the nature of privileged sites, the difference between oral tolerance and oral vaccination, why the route of immunization matters, whether the T(H)1-type response is really the immune system's primary defense, and whether there might be a different role for some regulatory T cells.     

Mitochondrial DNA variations associated with recurrent pregnancy loss among Indian women

Several genetic factors have been found to be associated with recurrent pregnancy loss (RPL). However, not many attempts have been made to associate the mitochondrial DNA (mtDNA) variations with RPL. Therefore, we have analyzed the complete mtDNA of 100 women with RPL and 12 aborted fetal tissues. Our analysis revealed a total of 681 variations, most of which were in NADH Dehydrogenase (ND) genes that encode mitochondrial enzyme Complex I. Presence of T4216C variation (ND1 gene) in 9% of the RPL women and several pathogenic, and novel mutations suggest the role of mtDNA variations in RPL.     

Evaluation of Procedures for Isolation of Nontuberculous Mycobacteria from Soil and Water

Six methods of decontamination each for the isolation of mycobacteria from soil and water were compared. On the basis of the results obtained, three of the six methods for soil and two of the six methods for water were further evaluated. For both soil and water samples, the method using 3% sodium lauryl sulfate in combination with 1% NaOH yielded more positives than the other methods.     

Isolation and Identification of Environmental Mycobacteria in the Mycobacterium bovis BCG Trial Area of South India

The isolation profiles of environmental mycobacteria present in soil, water, and dust samples, and sputum samples of persons with symptoms of chest infection in the South Indian Mycobacterium bovis BCG (bacillus Calmette-Guérin) trial area were compared. Isolates belonging to the Mycobacterium avium-intracellulare-scrofulaceum complex were predominant in water, dust, and sputum samples and Mycobacterium fortuitum-complex organisms were predominant in soil samples irrespective of the season of the year.     

Tetra substituted thiophenes as anti-inflammatory agents: exploitation of analogue-based drug design

A series of 17 novel tetra substituted thiophenes was designed, synthesized, and screened for anti-inflammatory activity in carrageenin induced rat paw edema model, an acute in vivo model. The lead molecule selected was Tenidap, a dual COX/LOX inhibitor. Compounds I (43%), III (60%), IV (60%), and VIII (64%) showed moderate to good anti-inflammatory activity. The best candidate among the whole series was VIII, which gave 64% protection to the inflamed paw. The side chain of candidate VIII had resemblance to that of Romazarit, a DMARD, which was withdrawn due to its toxicity profile. A probable reason for the metabolic stability of the proposed side chain not having the possibility of generating peroxy type radicals or acrylic acid moieties, unlike Romazarit, is discussed. The biological activity exhibited by the three designed series was in the order of methyl amino series > ethyl amino series > carbethoxy amino series. The –(CO)–CH₂–COOR side chain at the fifth position as in candidate VIII, the methyl amino group at the second position, and the ester at the third position of the thiophene can be considered as a three-point pharmacophore for designing better anti-inflammatory agents. The present study is a classical example of the exploitation of an analogue based drug design, which culminated in the development of good anti-inflammatory agents that have the potential of becoming dual inhibitors.     

Asian/American: Historical Crossings of a Racial Frontier

Asian/American: Historical Crossings of. Racial Frontier. David Palumbo-Liu. Stanford: Stanford University Press, 1999. 504 pp.     

Exoglycosidase purity and linkage specificity: assessment using oligosaccharide substrates and high-pH anion-exchange chromatography with pulsed amperometric detection

Simplified HPLC protocols to determine the activity and linkagespecificity and to detect the most commonly-encountered contaminantsin available exoglycosidase preparations (Jacob and Scudder,Methods Enzymol., 230, 280–300, 1994) were developed.Monosaccharides and oligosaccharides were analyzed in a singlechromatographic step using high-pH anion-exchange chromatographywith pulsed amperometric detection. All analyses were performedwith underivatized oligosaccharide substrates and by directinjection of unprocessed, diluted enzyme digests into the chromatograph.The sialidase from Newcastle disease virus was found to releaseboth a(2     

Hemodynamic Effects of Cardiovascular Medications in a Normovolemic and Hemorrhaged Yorkshire-cross Swine Model

The Yorkshire-cross swine model is a valuable translational model commonly used to study cardiovascular physiology and response to insult. Although the effects of vasoactive medications have been well described in healthy swine, the effects of these medications during hemorrhagic shock are less studied. In this study, we sought to expand the utility of the swine model by characterizing the hemodynamic changes that occurred after the administration of commonly available vasoactive medications during euvolemic and hypovolemic states. To this end, we anesthetized and established femoral arterial, central venous, and pulmonary arterial access in 15 juvenile Yorkshire-cross pigs. The pigs then received a series of rapidly metabolized but highly vasoactive medications in a standard dosing sequence. After completion of this sequence, each pig underwent a 30-mL/kg hemorrhage over 10 min, and the standard dosing sequence was repeated. We then used standard statistical techniques to compare the effects of these vasoactive medications on a variety of hemodynamic parameters between the euvolemic and hemorrhagic states. All subjects completed the study protocol. The responses in the hemorrhagic state were often attenuated or even opposite of those in the euvolemic state. For example, phenylephrine decreased the mean arterial blood pressure during the euvolemic state but increased it in the hemorrhagic state. These results clarify previously poorly defined responses to commonly used vasoactive agents during the hemorrhagic state in swine. Our findings also demonstrate the need to consider the complex and dynamic physiologic state of hemorrhage when anticipating the effects of vasoactive drugs and planning study protocols.

Biomedical research using animals is a critical element in the advancement of human healthcare worldwide. Pigs are an important species for translational research, because their physiologic responses to hemorrhage, traumatic brain injury, and other traumatic injuries simulates the human response more closely than any other nonprimate animal model.¹² Yorkshire-cross swine demonstrate cardiovascular responses to physiologic insult that are similar to the responses of people.^18,24,27,32 These pigs have been used to evaluate several abnormal hemodynamic states, including those found in cardiac disease,^20,29,36 vascular disease,^3,21,25 and shock.^26,30,35 Swine models are particularly important in military and combat research for study of the complex physiology during hemorrhage,^10,17,19 especially given that traumatic hemorrhage remains the leading cause of potentially survivable mortality in both civilian and military populations.^7-9,16The effects of vasoactive medications in healthy swine have been well described and in general are similar to those observed in humans.^6,15 However, the effects of these medications have been less studied during hemorrhagic shock, and those studies have typically been limited to the effects that develop after the administration of vasoactive medications^4,5,22 as compared with medications that have direct inotropic or chronotropic activity. In normovolemic subjects, most vasoconstrictive medications have predictable responses that can be quantified by measuring changes in blood pressure, systemic vascular resistance (SVR), stroke volume, heart rate (HR), and cardiac output. However, hemorrhage can induce significant changes in these indices^28,31 and in how vasoactive medications affect these indices. For example, hemorrhage tends to decrease systemic blood pressure, with a compensatory increase in heart rate.This study sought to expand the utility of the swine model by characterizing the hemodynamic changes observed after the administration of commonly used vasoactive medications during euvolemic and hypovolemic states. All of the study medications are highly selective, with rapid pharmacokinetics, and were chosen to selectively modify isolated components of cardiovascular physiology (e.g., preload, contractility, afterload).The first agent, phenylephrine, is a rapidly metabolized selective α1 adrenergic agonist that we selected for this study because of its broad use in both research and human clinical settings and its selective ability to increase SVR through direct arteriolar vasoconstriction. Previous studies in euvolemic swine with phenylephrine-induced hypertension showed significant increases in mean pulmonary artery pressure, mean arterial pressure (MAP), and SVR, with minimal influence on cardiac output and HR.³⁴ Second, nicardipine is a rapidly metabolized dihydropyridine calcium-channel blocker that is commonly used in human clinical practice. Its primary mechanism of action is direct arteriolar vasodilation. In previous studies of euvolemic swine, nicardipine decreased MAP and SVR.¹¹ Third, dobutamine is a rapidly metabolized β-adrenergic agonist that increases both cardiac ionotropy and chronotropy. Previous investigations in euvolemic swine found profound increases in HR, cardiac output, and MAP after dobutamine administration.² Fourth, esmolol is a highly selective β1 adrenergic antagonist that undergoes extremely rapid metabolism by nonspecific esterases in blood and tissue. It decreases both cardiac inotropy and chronotropy, and its administration leads to overall myocardial depression and decreased HR and MAP. Previous studies in swine showed decreased cardiac excitability and increased thresholds for the onset of malignant arrhythmias.³³ Finally, nitroglycerine increases venous capacitance through venous dilation, thereby causing a functional decrease in preload. The hemodynamic effects of nitroglycerine can vary depending on the subject’s physiologic state. In general, intravenous administration of nitroglycerine decreases MAP due to decreased cardiac output. This effect was demonstrated in euvolemic swine and was accompanied by a compensatory increase in HR.¹     

Age, sex, and race influence single-strand break repair capacity in a human population

Recently, we developed an improved comet assay protocol for evaluating single-strand break repair capacity (SSB-RC) in unstimulated cryopreserved human peripheral blood mononuclear cells (PBMCs). This methodology facilitates control of interexperimental variability [A.R. Trzeciak, J. Barnes, M.K. Evans, A modified alkaline comet assay for measuring DNA repair capacity in human populations. Radiat. Res. 169 (2008) 110-121]. The fast component of SSB repair (F-SSB-RC) was assessed using a novel parameter, the initial rate of DNA repair, and the widely used half-time of DNA repair. The slow component of SSB repair (S-SSB-RC) was estimated using the residual DNA damage after 60 min. We have examined repair of gamma-radiation-induced DNA damage in PBMCs from four age-matched groups of male and female whites and African-Americans between ages 30 and 64. There is an increase in F-SSB-RC with age in white females (P<0.01) and nonsignificant decrease in F-SSB-RC in African-American females (P=0.061). F-SSB-RC is lower in white females than in white males (P<0.01). There is a decrease in F-SSB-RC with age in African-American females as compared to white females (P<0.002) and African-American males (nonsignificant, P=0.059). Age, sex, and race had a similar effect on intercellular variability of DNA damage in gamma-irradiated and repairing PBMCs. Our findings suggest that age, sex, and race influence SSB-RC as measured by the alkaline comet assay. SSB-RC may be a useful clinical biomarker.     

Distribution and function of monoacylglycerol lipase in the gastrointestinal tract

The endogenous cannabinoid system plays an important role in the regulation of gastrointestinal function in health and disease. Endocannabinoid levels are regulated by catabolic enzymes. Here, we describe the presence and localization of monoacylglycerol lipase (MGL), the major enzyme responsible for the degradation of 2-arachidonoylglycerol. We used molecular, biochemical, immunohistochemical, and functional assays to characterize the distribution and activity of MGL. MGL mRNA was present in rat ileum throughout the wall of the gut. MGL protein was distributed in the muscle and mucosal layers of the ileum and in the duodenum, proximal colon, and distal colon. We observed MGL expression in nerve cell bodies and nerve fibers of the enteric nervous system. There was extensive colocalization of MGL with PGP 9.5 and calretinin-immunoreactive neurons, but not with nitric oxide synthase. MGL was also present in the epithelium and was highly expressed in the small intestine. Enzyme activity levels were highest in the duodenum and decreased along the gut with lowest levels in the distal colon. We observed both soluble and membrane-associated enzyme activities. The MGL inhibitor URB602 significantly inhibited whole gut transit in mice, an action that was abolished in cannabinoid 1 receptor-deficient mice. In conclusion, MGL is localized in the enteric nervous system where endocannabinoids regulate intestinal motility. MGL is highly expressed in the epithelium, where this enzyme may have digestive or other functions yet to be determined.