Purkinje cell dysfunction and loss in a knock-in mouse model of Huntington disease.

Huntington Disease (HD) is an autosomal dominant neurological disorder characterized by motor, psychiatric and cognitive disturbances. Recent evidence indicates that the viability and function of cerebellar Purkinje cells (PCs) are compromised in an aggressive mouse model of HD. Here we investigate whether this is also the case in the HdhQ200 knock-in mouse model of HD. Using quantitative-real time-PCR and immunofluorescence, we observed a loss of the PC marker and calcium buffer calbindin in 50week-old symptomatic mice. Reductions were also observed in parvalbumin and glutamic acid decarboxylase protein expression, most markedly in the molecular cell layer. Stereological analysis revealed an overall reduction in the PC population in HdhQ200/Q200 mice by nearly 40%, and loose patch electrophysiology of remaining PCs indicated a reduction in firing rate in HD mice compared to control littermates. Taken together, these data demonstrate that PC survival and function are compromised in a mouse model of adult-onset HD and suggest that further experiments should investigate the contribution of PC death and dysfunction to HD-associated motor impairment.

Disruption of Purkinje cell function prior to huntingtin accumulation and cell loss in an animal model of Huntington disease.

Huntington Disease (HD) is a devastating neurological disorder characterized by progressive deterioration of psychiatric, motor, and cognitive function. Purkinje cells (PCs), the output neurons of the cerebellar cortex, have been found to be vulnerable in multiple CAG repeat disorders, but little is known about the involvement of PC dysfunction in HD. To investigate possible PC abnormalities, we performed quantitative real time PCR, Western blot analysis, and immunohistochemistry experiments to explore the changes in PC markers in the R6/2 mouse model of severe HD. There were reductions in the transcript and protein levels of the calcium-binding proteins parvalbumin and calbindin, as well as the enzyme glutamic acid decarboxylase 67. Immunohistochemistry supported these results, with the most substantial changes occurring in the PC layer. To determine whether the reductions in PC marker expression were due to cell loss, we performed stereology on both presymptomatic and end-stage R6/2 mice. Stereological counts indicated a significant reduction in PC number by end-stage but no change in presymptomatic animals (4 weeks of age). To assess cellular function prior to cell loss and symptom onset, we measured spontaneous firing in PCs from 4-week old animals and found a striking deficit in PC firing as indicated by a 57% decrease in spike rate. Interestingly, huntingtin inclusions were not widely observed in PCs until 12 weeks of age, indicating that soluble huntingtin and/or abnormalities in other cell types may contribute to PC dysfunction. Considering the roles for PCs in motor control, these data suggest that early PC dysfunction potentially contributes to motor impairment in this model of HD.

On-line characterization of YBCO coated conductors using Raman spectroscopy methods.

The use of Raman spectroscopy for on-line monitoring of the production of superconducting YBa2Cu3O6+X (YBCO) thin films on long-length metal tapes coated with textured buffer layers is reported for the first time. A methodology is described for obtaining Raman spectra of YBCO on moving tape exiting a metal-organic-chemical-vapor-deposition (MOCVD) enclosure. After baseline correction, the spectra recorded in this way show the expected phonons of the specific YBCO crystal orientation required for high supercurrent transport, as well as phonons of non-superconducting second-phase impurities when present. It is also possible to distinguish YBCO films that are properly textured from films having domains of misoriented YBCO grains. An investigation of the need for focus control on moving tape indicated that focusing of the laser on the surface of the highly reflective YBCO films exiting the MOCVD enclosure tends to produce aberrant photon bursts that swamp the Raman spectrum. These photon bursts are very likely a consequence of optical speckle effects induced by a combination of surface roughness, crystallographic texture, and/or local strain within the small grain microstructure of the YBCO film. Maintaining a slightly out-of-focus condition provides the best signal-to-noise ratio in terms of the obtained Raman spectra. In addition to examining moving tape at the post-MOCVD stage, Raman spectra of the film surface can also be recorded after the oxygen anneal performed to bring the YBCO to the optimum superconducting state. Consideration is given to data processing methods that could be adapted to the on-line Raman spectra to allow the tagging of out-of-specification tape segments and, at a more advanced level, feedback control to the MOCVD process.

The murine mutation scurfy (sf) results in an antigen-dependent lymphoproliferative disease with altered T cell sensitivity.

The scurfy (sf) murine mutation results in a rapidly fatal lymphoproliferative disease, causing death by 26 days. Mature CD4+ T cells which tested hyperresponsive to T cell receptor (TCR) stimulation are involved. When sf was bred onto a transgenic line (DO11.10) in which 75 - 95 % of the T cells express TCR for ovalbumin (OVA) 323 - 339, sf / Y OVA mice had prolonged lifespans and less severe clinical symptoms compared to controls. However, sf / Y OVA mice eventually developed disease and died with manifestations similar to those of the original sf strain. The Rag1 knockout (KO) mouse, which cannot produce mature T (or B) cells without the addition of functional transgenes, was chosen for further breeding. The combination of Rag1 KO, the OVA transgene, and sf produced mice with 100 % of their mature DO11.10 alpha beta T cells reactive strictly to OVA peptide. None of these Rag1 - / - sf / Y OVA mice developed the scurfy disease. They retained central deletion capability in vivo, but demonstrated an altered in vitro response to OVA peptide. These results indicate that mice without TCR for endogenous antigens do not develop scurfy symptoms, and are consistent with the hypothesis that the sf mutation requires antigen stimulation to manifest disease, perhaps via altered TCR sensitivity.

Depression determines illness conviction and pain impact: a structural equation modeling analysis.

OBJECTIVE: The present study sought to derive an algorithm using factor analysis and structural equation modeling (SEM) to describe headache and orofacial pain patients using measures of behavioral and psychological functioning. This investigation further examined whether the underlying factor structure differed in 3 presumed distinct diagnostic categories: myofascial, neuropathic, and neurovascular pain. DESIGN: The Minnesota Multiphasic Personality Inventory-2 (MMPI-2), Multidimensional Pain Inventory (MPI), Beck Depression Inventory-II (BDI-II), and visual analog scale for functional limitation (VAS-FL) were administered to the subjects. A split group design was used. Exploratory factor analysis (EFA) was used to describe distinct factor domains in the first group. Confirmatory factor analysis (CFA) using SEM tested this structure in the second group and described causal relationships between the revealed (latent) factors. Analysis of variance (ANOVA) was used to test for differences in demographic variables and diagnostic group factor structure. SETTING: The Pain Center is a comprehensive, multidisciplinary pain medicine program at Cedars-Sinai Medical Center, Los Angeles, California. SUBJECTS: Three hundred and ninety (N = 390) subjects were assigned to 1 of 3 diagnostic categories: myofascial pain syndrome, neuropathic pain, or neurovascular pain. RESULTS: EFA revealed a 3-factor solution. The factors were labeled Depression, Illness Conviction, and Pain Impact, reflecting the content of their respective variables with highest loadings. CFA using SEM validated the 3-factor solution, and further revealed that Depression was a critical causal factor determining Illness Conviction and Pain Impact. No causal relationship was observed between Illness Conviction and Pain Impact. ANOVA found no differences in demographics. No difference in factor structure emerged for the 3 diagnostic categories. CONCLUSIONS: Analysis derived a 3-factor solution. The factors were Pain Impact, Illness Conviction, and Depression. SEM revealed the critical causal pathway showing that Depression determined Illness Conviction and Pain Impact. We conclude that the main target for pain treatment is depression. No differences in factor structure were found for the 3 diagnostic categories of myofascial, neuropathic, or neurovascular pain. This suggests that psychological processes are similar in chronic headache and orofacial pain patients despite their presumed distinct underlying pathophysiological mechanisms. SME is a powerful methodology to construct causal models that has been underutilized in the pain literature.

Vascular adhesion protein 1 mediates binding of T cells to human hepatic endothelium.

BACKGROUND & AIMS: Molecules that regulate T-cell adhesion to hepatic endothelium and thereby recirculation of T cells to the liver are poorly understood. Because the adhesion molecule vascular adhesion protein-1 (VAP-1), which mediates lymphocyte binding to lymph node endothelium, is expressed on hepatic endothelium, it could play a role in regulating T-cell recruitment to the liver. The aim of this study was to investigate the distribution of VAP-1 expression in human liver and the ability of VAP-1 to support T-cell binding to hepatic endothelium in vitro. METHODS: Hepatic VAP-1 expression was investigated using immunohistochemistry and specific monoclonal antibodies, and VAP-1-mediated adhesion to hepatic endothelium was investigated with a tissue-binding adhesion assay using human liver sections. RESULTS: VAP-1 was expressed on sinusoidal and vascular endothelium in non-inflamed liver and in inflamed liver from patients with either allograft rejection or primary biliary cirrhosis. T cells from healthy donors bound to hepatic endothelium when added to noninflamed liver sections; this binding was inhibited by a specific anti-VAP-1 antibody but not by antibodies to intercellular adhesion molecule 1, lymphocyte function--associated antigen 1, or very late after activation (antigen) 4. VAP-1--mediated adhesion was unaffected by T-cell activation with phorbol ester. CONCLUSIONS: VAP-1 is constitutively expressed on hepatic endothelium and mediates T-cell adhesion to hepatic endothelium in vitro. VAP-1 could play a critical role in regulating T-cell recirculation to the liver in vivo.

The heavy metal subculture and suicide.

The impact of the heavy metal music subculture on suicide has been the subject of much public debate but little scholarly research. The present paper assesses this relationship with data on heavy metal magazine subscriptions and youth suicide in the 50 states. We find that, controlling for other predictors of suicide, the greater the strength of the metal subculture, the higher the youth suicide rate. The music perhaps nurtures suicidal tendencies already present in the subculture. The model explains 51% of the variance in youth suicide.

Myofascial pain may present clinically as occipital neuralgia.

Three case presentations illustrate that the clinical signs and symptoms of occipital neuralgia may be produced by myofascial pain. Assessment of myofascial trigger points is needed before making a diagnosis of occipital neuralgia. Myofascial trigger points can be effectively treated with minimally invasive procedures, thereby avoiding irreversible surgical interventions.

Anesthesia, amnesia, and the memory/awareness distinction.

Several studies have shown that surgical patients cannot consciously recall or recognize events to which they had been exposed during general anesthesia. Might evidence of memory for intraoperative events be revealed through the performance of a postoperative test that does not require remembering to be deliberate or intentional? Results of the present study, involving the recognition and spelling of semantically biased homophones, suggest a negative answer to this question and imply that intraoperative events cannot be remembered postoperatively, either with or without awareness.

Heart-rate reactivity to cold pressor stress following biofeedback training.

Three previous studies have shown that biofeedback training is useful in modifying heart-rate and pain ratings during ice water stimulation (cold pressor test). Subjects were given an initial cold pressor followed by heart-rate biofeedback training and a final cold pressor test in which they were instructed to control their heart rate in accordance with the prior training. It was assumed that a heart-rate control skill had been learned. In the present study, two groups of subjects (N = 9 each) were given either increase or decrease heart-rate biofeedback training following the same procedures as previously, but subjects were not instructed to control their heart rate during the final cold pressor test. Heart rate, skin conductance, electromyographic activity, and respiration were measured. The biofeedback training effects replicate the previous results. However, no heart-rate or pain rating differences were found between the two groups during the final cold pressor test. Thus, previous findings cannot be accounted for simply by a shift in heart rate and/or pain reactivity following training itself. The findings suggest that a biofeedback strategy may be useful in modifying physiological and subjective responses to painful stimuli but only if it can be used as an active coping skill.

EMG-biofeedback reduction of tension headache: a cognitive skills-training approach.

The biofeedback literature affirms the therapeutic efficacy of EMG-biofeedback-assisted relaxation for the treatment of tension headache. However, this form of therapy has failed to focus on the role of cognitive variables in the control and perception of tension headache. The present case study provides a prototype treatment combining cognitive behavior--modification procedures with EMG-biofeedback training to treat a subject with chronic tension headache. Phase I, baseline, involved collecting mean EMG and daily headache activity, emphasizing specification of environmental stressors. Phase II, cognitive skills--training, focused on: (1) identifying negative self-statements (cognitions) related to stressors, and (2) training the subject to replace negative self-statements with coping self-instructions. This treatment resulted in a 33% headache reduction over baseline, with no concomitant changes in frontalis EMG. Phase III, EMG-biofeedback training, resulted in a 38% reduction in mean EMG level and a 66% reduction in mean headache activity when compared to baseline. The results suggest the importance of attending to cognitive factors in the treatment of tension headache.