Kappa Opioid Receptors in Mesolimbic Terminals Mediate Escalation of Cocaine Consumption.

Increases in drug consumption over time, also known as escalation, is a key behavioral component of substance use disorder (SUD) that is related to potential harm to users, such as overdose. Studying escalation also allows researchers to investigate the transition from casual drug use to more SUD-like drug use. Understanding the neurobiological systems that drive this transition will inform therapeutic treatments in the aim to prevent increases in drug use and the development of SUD. The kappa opioid receptor (KOR) system is typically known for its role in negative affect, which is commonly found in SUD as well. Furthermore, the KOR system has also been implicated in drug use and importantly, modulating the negative effects of drug use. However, the specific neuronal subpopulation expressing KOR involved has not been identified. Here, we first demonstrated that pharmacologically inhibiting KOR in the nucleus accumbens core (NAcC), as a whole, blocks cocaine escalation under long-access self-administration conditions. We then demonstrated that KOR expressed on ventral tegmental area (VTA) neurons but not NAcC neurons is sufficient for blocking cocaine escalation by utilizing a novel virally-mediated CRISPR-SaCas9 knock-out of the oprk1 gene. Together, this suggests that activation of KOR on VTA terminals in the NAcC drives the transition to the SUD-like phenotype of escalation of cocaine consumption.

Virologic studies in rheumatoid arthritis and other connective tissue diseases.

A total of 187 specimens from 142 subjects with rheumatoid arthritis, systemic lupus erythematosus, other connective tissue diseases, and controls were placed in cell culture. Specimens from 119 of the subjects grew, lasting over 2 yr in several instances. No evidence of virus infection has been found by a variety of sensitive methods, including cell fusion. Other approaches have likewise failed thus far to implicate any virus in the pathogenesis of rheumatoid arthritis.

Oligodendrocyte-specific expression and autoantigenicity of transaldolase in multiple sclerosis.

Although the etiology of multiple sclerosis (MS) is unknown, there is compelling evidence that its pathogenesis is mediated through the immune system. Molecular mimicry, i.e., crossreactivity between self-antigens and viral proteins, has been implicated in the initiation of autoimmunity and MS. Based on homology to human T cell lymphotropic virus type I (HTLV-I) a novel human retrotransposon was cloned and found to constitute an integral part of the coding sequence of the human transaldolase gene (TAL-H). TAL-H is a key enzyme of the nonoxidative pentose phosphate pathway (PPP) providing ribose-5-phosphate for nucleic acid synthesis and NADPH for lipid biosynthesis. Another fundamental function of the PPP is to maintain glutathione at a reduced state and, consequently, to protect sulfhydryl groups and cellular integrity from oxygen radicals. Immunohistochemical analyses of human brain sections and primary murine brain cell cultures demonstrated that TAL is expressed selectively in oligodendrocytes at high levels, possibly linked to production of large amounts of lipids as a major component of myelin, and to the protection of the vast network of myelin sheaths from oxygen radicals. High-affinity autoantibodies to recombinant TAL-H were detected in serum (25/87) and cerebrospinal fluid (15/20) of patients with MS. By contrast, TAL-H antibodies were absent in 145 normal individuals and patients with other autoimmune and neurological diseases. In addition, recombinant TAL-H stimulated proliferation and caused aggregate formation of peripheral blood lymphocytes from patients with MS. Remarkable amino acid sequence homologies were noted between TAL-H and core proteins of human retroviruses. Presence of crossreactive antigenic epitopes between recombinant TAL-H and HTLV-I/human immunodeficiency virus type 1 (HIV-1) gas proteins was demonstrated by Western blot analysis. The results suggest that molecular mimicry between viral core proteins and TAL-H may play a role in breaking immunological tolerance and leading to a selective destruction of oligodendrocytes in MS.

Myxovirus antibody increases in human connective tissue disease.

Antibodies to measles and parainfluenza type 1 viruses were significantly increased in systemic lupus erythematosus and Reiter's syndrome. Of the individuals with highest titers of measles antibody, 75 percent had neurologic illness. Persistent virus infection may be a factor in the pathogenesis of these diseases.

Tetrachlorodibenzodioxin: an accidental poisoning episode in horse arenas.

Tetrachlorodibenzodioxin was identified as the apparent cause of an outbreak of poisoning in humans, horses, and other animals. Exposure was related to the spraying of contaminated waste oil on riding arenas for dust control. The contamination resulted from improper disposal of a toxic industrial waste. The pathologic effects and chemical identification of tetrachlorodibenzodioxin are described.

Corticotropin-releasing factor increases mouse ventral tegmental area dopamine neuron firing through a protein kinase C-dependent enhancement of Ih.

Stress induces the release of the peptide corticotropin-releasing factor (CRF) into the ventral tegmental area (VTA), and also increases dopamine levels in brain regions receiving dense VTA input. Therefore, stress may activate the mesolimbic dopamine system in part through the actions of CRF in the VTA. Here, we explored the mechanism by which CRF affects VTA dopamine neuron firing. Using patch-clamp recordings from brain slices we first determined that the presence of I(h) is an excellent predictor of dopamine content in mice. We next showed that CRF dose-dependently increased VTA dopamine neuron firing, which was prevented by antagonism of the CRF receptor-1 (CRF-R1), and was mimicked by CRF-R1 agonists. Inhibition of the phospholipase C (PLC)-protein kinase C (PKC) signalling pathway, but not the cAMP-protein kinase A (PKA) signalling pathway, prevented the increase in dopamine neuron firing by CRF. Furthermore, the effect of CRF on VTA dopamine neurons was not attenuated by blockade of I(A), I(K(Ca)) or I(Kir), but was completely eliminated by inhibition of I(h). Although cAMP-dependent modulation of I(h) through changes in the voltage dependence of activation is well established, we surprisingly found that CRF, through a PKC-dependent mechanism, enhanced I(h) independent of changes in the voltage dependence of activation. Thus, our results demonstrated that CRF acted on the CRF-R1 to stimulate the PLC-PKC signalling pathway, which in turn enhanced I(h) to increase VTA dopamine neuron firing. These findings provide a cellular mechanism of the interaction between CRF and dopamine, which can be involved in promoting the avoidance of threatening stimuli, the pursuit of appetitive behaviours, as well as various psychiatric conditions.

MAP1D, a novel methionine aminopeptidase family member is overexpressed in colon cancer.

N-terminal methionine removal is an important cellular process required for proper biological activity, subcellular localization, and eventual degradation of many proteins. The enzymes that catalyze this reaction are called Methionine Aminopeptidases (MAPs). To date, only two MAP family members, MAP1A and MAP2, have been well characterized and studied in mammals. In our studies, we have cloned a full length MAP1D gene. Expression and purification of full length recombinant protein shows that the sequence encodes an enzyme with MAP activity. MAP1D is overexpressed in colon cancer cell lines and in colon tumors as compared to matched normal tissue samples. Downregulation of MAP1D expression by shRNA in HCT-116 colon carcinoma cells reduces anchorage-independant growth in soft agar. These data suggest that MAP1D is a potentially oncogenic, novel member of the MAP gene family that may play an important role in colon tumorigenesis.

Comparative analysis of antibody and cell-mediated autoimmunity to transaldolase and myelin basic protein in patients with multiple sclerosis.

Antibody and T cell-mediated immune responses to oligodendroglial autoantigens transaldolase (TAL) and myelin basic protein (MBP) were examined in patients with multiple sclerosis (MS). Immunohistochemical studies of postmortem brain sections revealed decreased staining by MBP- and TAL-specific antibodies in MS plaques, indicating a concurrent loss of these antigens from demyelination sites. By Western blot high titer antibodies to human recombinant TAL were found in 29/94 sera and 16/23 cerebrospinal fluid samples from MS patients. Antibodies to MBP were undetectable in sera or cerebrospinal fluid of these MS patients. Proliferative responses to human recombinant TAL (stimulation index [SI] = 2.47+/-0.3) were significantly increased in comparison to MBP in 25 patients with MS (SI = 1.37+/-0.1; P < 0.01). After a 7-d stimulation of PBL, utilization of any of 24 different T cell receptor Vbeta gene segments in response to MBP was increased less than twofold in the two control donors and six MS patients investigated. In response to TAL-H, while skewing of individual Vbeta genes was also less than twofold in healthy controls, usage of specific Vbeta gene segments was differentially increased ranging from 2.5 to 65.9-fold in patients with MS. The results suggest that TAL may be a more potent immunogen than MBP in MS.

Celiac disease in a patient with systemic lupus erythematosus: a case report and review of literature.

Celiac disease (CD) is an inflammatory condition of the gut with a known autoimmune pathogenesis. Many similarities exist between the pathogenesis of CD and systemic lupus erythematosus (SLE); it is still unknown whether there is an association. There are 13 case reports in the literature of both diseases occurring simultaneously. We report another patient who was diagnosed with SLE and 8 years later, developed CD. A review of the literature is also presented.

Weighing up the benefits of work: behavioral and neural analyses of effort-related decision making.

How we decide whether a course of action is worth undertaking is largely unknown. Recently, neuroscientists have been turning to ecological approaches to address this issue, examining how animals evaluate the costs and benefits of different options. We present here evidence from rodents and monkeys that demonstrate the degree to which they take into account work and energetic requirements when deciding what responses to make. These calculations appear to be critically mediated by the anterior cingulate cortex (ACC) and mesolimbic dopamine (DA) pathways, with damage to either causing a bias towards options that are easily obtained but yield relatively smaller reward rather than alternatives that require more work but result in greater reward. The evaluation of such decisions appears to be carried out in systems independent of those involved in delay-discounting. We suggest that top-down signals from ACC to nucleus accumbens (NAc) and/or midbrain DA cells may be vital for overcoming effort-related response costs.

Physics design of the in-vessel collection optics for the ITER electron cyclotron emission diagnostic.

Measurement of the electron cyclotron emission (ECE) is one of the primary diagnostics for electron temperature in ITER. In-vessel, in-vacuum, and quasi-optical antennas capture sufficient ECE to achieve large signal to noise with microsecond temporal resolution and high spatial resolution while maintaining polarization fidelity. Two similar systems are required. One views the plasma radially. The other is an oblique view. Both views can be used to measure the electron temperature, while the oblique is also sensitive to non-thermal distortion in the bulk electron distribution. The in-vacuum optics for both systems are subject to degradation as they have a direct view of the ITER plasma and will not be accessible for cleaning or replacement for extended periods. Blackbody radiation sources are provided for in situ calibration.

Temperature gradient scale length measurement: A high accuracy application of electron cyclotron emission without calibration.

Calibration is a crucial procedure in electron temperature (Te) inference from a typical electron cyclotron emission (ECE) diagnostic on tokamaks. Although the calibration provides an important multiplying factor for an individual ECE channel, the parameter ΔTe/Te is independent of any calibration. Since an ECE channel measures the cyclotron emission for a particular flux surface, a non-perturbing change in toroidal magnetic field changes the view of that channel. Hence the calibration-free parameter is a measure of Te gradient. BT-jog technique is presented here which employs the parameter and the raw ECE signals for direct measurement of electron temperature gradient scale length.

Evidence for a role for insulin and growth hormone in overnight regulation of 3-hydroxybutyrate in normal and diabetic adolescents.

OBJECTIVE: To determine the relative effects of growth hormone and insulin on ketogenesis during puberty. RESEARCH DESIGN AND METHODS: We studied overnight changes in plasma ketones--3-hydroxybutyrate and acetoacetate--in 35 normal and 26 IDDM adolescents at different stages of puberty. The diabetic adolescents either were on their normal insulin regimen or were studied during an overnight euglycemic clamp with or without suppression of endogenous growth hormone release. RESULTS: Total ketone body and 3-hydroxybutyrate concentrations in the normal adolescents rose significantly from 2000 (29 +/- 5 microM), reaching a peak at 0200 (103 +/- 16 microM, P < 0.001 vs. 2000). After a brief fall, a further rise occurred before breakfast. Fasting 3-hydroxybutyrate concentrations showed a negative correlation with fasting insulin levels (r = -0.46, P = 0.005) and decreased with advancing puberty, while insulin concentrations increased. In the diabetic patients on their usual insulin regimen, free insulin levels waned overnight, and an exaggerated rise in ketones was observed before breakfast. During the euglycemic clamp studies, ketone levels were higher than normal throughout the night. Mean overnight growth hormone and free insulin levels also were higher than in the normal control subjects. The addition of the anticholinergic drug pirenzepine reduced growth hormone secretion and obliterated the early-night peak of 3-hydroxybutyrate. CONCLUSIONS: We conclude that the early-night peak of ketone concentrations is related to growth hormone release, whereas the fasting levels are largely determined by insulin concentration. Inadequate insulin delivery in the presence of the high growth hormone concentrations characteristic of diabetic adolescents could lead to rapid decompensation and ketoacidosis.

Effect of aspirin on exercise-induced angina.

Suspecting that platelet thromboemboli could play a role in the pathogenesis of myocardial ischemia, we did a random-order, double-blind, crossover study of the effect of the platelet aggregation inhibitor, aspirin, on treadmill exercise-induced angina in 13 men with coronary artery disease. Although collagen-induced platelet aggregation and the second phase of adenosine diphosphate (ADP)-induced platelet aggregation were significantly decreased and the rate of disaggregation of ADP-induced platelet aggregates was significantly increased after 650 mg aspirin in buffered solution, there was no delay in onset of exercise-induced angina, change in heart rate-blood pressure product at onset of angina, or change in S-T segment depression at onset of angina. Regardless of whether the patients had received placebo or aspirin on the preceding day, treadmill exercise until angina was followed by no changes in platelet aggregation or disaggregation, platelet count in blood or platelet-rich plasma, or of the plasma concentration of nonesterified fatty acids.

Failure of methylhistidines to inhibit platelet aggregation at concentrations found in uremic plasma.

Methylhistidines are among the amino acids which are present in increased concentrations in the plasma of severely uremic patients who may have a hemorrhagic diathesis. Histidine contains an imidazole ring, and our previous work has shown inhibition of collagen-induced platelet aggregation by imidazole in concentrations as low as 0.5 mM. Collagen-induced, adenosine diphosphate-induced, and norepinephrine-induced platelet aggregation were tested in platelet-rich plasma by a turbidimetric technique after incubation of the plasma with varying concentrations of the methylhistidines for 1 hour. Platelet aggregation was unaffected by methylhistidine concentrations up to 0.6 mM. Only norepinephrine-induced platelet aggregation was slightly inhibited at a concentration of 4.7 (mM far higher than found in uremic patients). The imidazole ring as a portion of the methylhistidine molecule appears to have lost much of its effect on platelet aggregation.

Synthesis and antitumor activity of ester-modified analogues of bengamide B.

Bengamide B, a novel sponge-derived marine natural product with broad spectrum antitumor activity, was not suitable for further preclinical development because of its difficult synthesis and very poor water solubility. Bengamide B produced a 31% T/C at its solubility-limited maximum intravenous dose of 33 micromol/kg in MDA-MB-435 breast carcinoma implanted subcutaneously as a xenograft in nude mice. Compound 8a, a bengamide B analogue with three structural changes (t-Bu alkene substituent, unsubstituted lactam nitrogen, and inverted lactam 5'-myristoyloxy group), was as potent as bengamide B in vitro and more efficacious than bengamide B in vivo. A series of ester-modified analogues based on 8a were synthesized and tested in vitro and in vivo (MDA-MB-435). The cyclohexyl- and phenethyl-substituted esters, 8c and 8g, respectively, had in vitro and in vivo activities similar to that of 8a and enhanced water solubility (ca. 1 mg/mL). Consequently, 8c and 8g were tested in the MDA-MB-435 xenograft model at 100 micromol/kg and produced 29% and 57% tumor regression, respectively.

A role for presynaptic mechanisms in the actions of nomifensine and haloperidol.

Psychomotor stimulants and neuroleptics exert multiple effects on dopaminergic signaling and produce the dopamine (DA)-related behaviors of motor activation and catalepsy, respectively. However, a clear relationship between dopaminergic activity and behavior has been very difficult to demonstrate in the awake animal, thus challenging existing notions about the mechanism of these drugs. The present study examined whether the drug-induced behaviors are linked to a presynaptic site of action, the DA transporter (DAT) for psychomotor stimulants and the DA autoreceptor for neuroleptics. Doses of nomifensine (7 mg/kg i.p.), a DA uptake inhibitor, and haloperidol (0.5 mg/kg i.p.), a dopaminergic antagonist, were selected to examine characteristic behavioral patterns for each drug: stimulant-induced motor activation in the case of nomifensine and neuroleptic-induced catalepsy in the case of haloperidol. Presynaptic mechanisms were quantified in situ from extracellular DA dynamics evoked by electrical stimulation and recorded by voltammetry in the freely moving animal. In the first experiment, the maximal concentration of electrically evoked DA ([DA](max)) measured in the caudate-putamen was found to reflect the local, instantaneous change in presynaptic DAT or DA autoreceptor activity according to the ascribed action of the drug injected. A positive temporal association was found between [DA](max) and motor activation following nomifensine (r=0.99) and a negative correlation was found between [DA](max) and catalepsy following haloperidol (r=-0.96) in the second experiment. Taken together, the results suggest that a dopaminergic presynaptic site is a target of systemically applied psychomotor stimulants and regulates the postsynaptic action of neuroleptics during behavior. This finding was made possible by a voltammetric microprobe with millisecond temporal resolution and its use in the awake animal to assess release and uptake, two key mechanisms of dopaminergic neurotransmission. Moreover, the results indicate that presynaptic mechanisms may play a more important role in DA-behavior relationships than is currently thought.

Needle biopsy of the synovium of children.

While the diagnosis of juvenile rheumatoid arthritis is based on clinical criteria and does not require confirmation by synovial biopsy, biopsy is occasionally desired to exclude other diagnoses. Needle synovial biopsy of the knee may be performed on young children as an office procedure and generally provides adequate tissue for examination. In the author's clinic this procedure has replaced open biopsy of the knee of children.

Infection and chronic rheumatic disease in children.

It is clear that various microbial agents can cause acute and chronic rheumatic disease by several mechanisms, that different agents, some perhaps yet unknown, may cause the same disease in different patients, and that genetic factors are important, perhaps crucial, to this host response. In trying to elucidate how microbe-host interactions result in chronic rheumatic disease, interest currently centers on the roles of genetic factors, of bacterial infections including endogenous flora, of cross-reactive microbial and host antigens, and of the immune response to them. As in the past, progress in understanding these complex interactions will probably be incremental and intermittent.