Acquisition of a simple motor skill: task-dependent adaptation and long-term changes in the human soleus stretch reflex

Changing the H reflex through operant conditioning leads to CNS multisite plasticity and can affect previously learned skills. To further understand the mechanisms of this plasticity, we operantly conditioned the initial component (M1) of the soleus stretch reflex. Unlike the H reflex, the stretch reflex is affected by fusimotor control, comprises several bursts of activity resulting from temporally dispersed afferent inputs, and may activate spinal motoneurons via several different spinal and supraspinal pathways. Neurologically normal participants completed 6 baseline sessions and 24 operant conditioning sessions in which they were encouraged to increase (M1up) or decrease (M1down) M1 size. Five of eight M1up participants significantly increased M1; the final M1 size of those five participants was 143 ± 15% (mean ± SE) of the baseline value. All eight M1down participants significantly decreased M1; their final M1 size was 62 ± 6% of baseline. Similar to the previous H-reflex conditioning studies, conditioned reflex change consisted of within-session task-dependent adaptation and across-session long-term change. Task-dependent adaptation was evident in conditioning session 1 with M1up and by session 4 with M1down. Long-term change was evident by session 10 with M1up and by session 16 with M1down. Task-dependent adaptation was greater with M1up than with the previous H-reflex upconditioning. This may reflect adaptive changes in muscle spindle sensitivity, which affects the stretch reflex but not the H reflex. Because the stretch reflex is related to motor function more directly than the H reflex, M1 conditioning may provide a valuable tool for exploring the functional impact of reflex conditioning and its potential therapeutic applications. NEW & NOTEWORTHY Since the activity of stretch reflex pathways contributes to locomotion, changing it through training may improve locomotor rehabilitation in people with CNS disorders. Here we show for the first time that people can change the size of the soleus spinal stretch reflex through operant conditioning. Conditioned stretch reflex change is the sum of task-dependent adaptation and long-term change, consistent with H-reflex conditioning yet different from it in the composition and amount of the two components.

High CCL27 immunoreactivity in 'supratumoral' epidermis correlates with better prognosis in patients with cutaneous malignant melanoma

AIMS

It has been proposed that the expression of chemokines and chemokine receptors by melanoma cells may have a role in tumour immune escape. Chemokine CCL27 is reported to be expressed specifically on the epidermal keratinocytes. The implication of CCL27 in cutaneous melanomas is currently unresolved. It has been suggested that CCL27 expression in melanomas can induce antitumoral immunity, and that CCL27 may suppress tumour growth probably due to the local lymphocyte recruitment.

METHODS

We studied CCL27 chemokine expression in three different concentric epidermal areas covering the primary cutaneous melanoma in patients with a long clinical follow-up. Our study included 91 cases of primary melanomas of the skin diagnosed during the 10-year period 1992-2002, and a minimum clinical follow-up of 10 years.

RESULTS

We evaluated three different concentric and easily reproducible areas in the epidermis: the area covering melanoma (which we called 'supratumoral'), the area adjacent to the tumour ('peritumoral') and the most peripheral epidermal area ('peripheral'). Only CCL27 expression in supratumoral epidermis correlated with clinical outcome.

CONCLUSIONS

Our study showed that a higher immunostaining of CCL27 in supratumoral epidermis is associated with longer progression-free interval and melanoma-specific survival.

Endothelial function and insulin sensitivity during acute non-esterified fatty acid elevation: Effects of fat composition and gender

BACKGROUND AND AIMS

We have reported that adverse effects on flow-mediated dilation of an acute elevation of non-esterified fatty acids rich in saturated fat (SFA) are reversed following addition of long-chain (LC) n-3 polyunsaturated fatty acids (PUFA), and hypothesised that these effects may be mediated through alterations in insulin signalling pathways. In a subgroup, we explored the effects of raised NEFA enriched with SFA, with or without LC n-3 PUFA, on whole body insulin sensitivity (SI) and responsiveness of the endothelium to insulin infusion.

METHODS AND RESULTS

Thirty adults (mean age 27.8 y, BMI 23.2 kg/m(2)) consumed oral fat loads on separate occasions with continuous heparin infusion to elevate NEFA between 60 and 390 min. For the final 150 min, a hyperinsulinaemic-euglycaemic clamp was performed, whilst FMD and circulating markers of endothelial function were measured at baseline, pre-clamp (240 min) and post-clamp (390 min). NEFA elevation during the SFA-rich drinks was associated with impaired FMD (P = 0.027) whilst SFA + LC n-3 PUFA improved FMD at 240 min (P = 0.003). In males, insulin infusion attenuated the increase in FMD with SFA + LC n-3 PUFA (P = 0.049), with SI 10% greater with SFA + LC n-3 PUFA than SFA (P = 0.041).

CONCLUSION

This study provides evidence that NEFA composition during acute elevation influences both FMD and SI, with some indication of a difference by gender. However our findings are not consistent with the hypothesis that the effects of fatty acids on endothelial function and SI operate through a common pathway. This trial was registered at clinical trials.gov as NCT01351324 on 6th May 2011.

New limit on time-reversal violation in beta decay

We report the results of an improved determination of the triple correlation DP·(p(e)×p(v)) that can be used to limit possible time-reversal invariance in the beta decay of polarized neutrons and constrain extensions to the standard model. Our result is D=[-0.96±1.89(stat)±1.01(sys)]×10(-4). The corresponding phase between gA and gV is ϕAV=180.013°±0.028° (68% confidence level). This result represents the most sensitive measurement of D in nuclear β decay.

Invited article: development of high-field superconducting Ioffe magnetic traps

We describe the design, construction, and performance of three generations of superconducting Ioffe magnetic traps. The first two are low current traps, built from four racetrack shaped quadrupole coils and two solenoid assemblies. Coils are wet wound with multifilament NbTi superconducting wires embedded in epoxy matrices. The magnet bore diameters are 51 and 105 mm with identical trap depths of 1.0 T at their operating currents and at 4.2 K. A third trap uses a high current accelerator-type quadrupole magnet and two low current solenoids. This trap has a bore diameter of 140 mm and tested trap depth of 2.8 T. Both low current traps show signs of excessive training. The high current hybrid trap, on the other hand, exhibits good training behavior and is amenable to quench protection.

Preparation of liposomes from milk fat globule membrane phospholipids using a microfluidizer

The isolation of milk fat globule membrane (MFGM) material from buttermilk on a commercial scale has provided a new ingredient rich in phospholipids and sphingolipids. An MFGM-derived phospholipid fraction was used to produce liposomes via a high-pressure homogenizer (Microfluidizer). This technique does not require the use of solvents or detergents, and is suitable for use in the food industry. The liposome dispersion had an average hydrodynamic diameter of 95 nm, with a broad particle-size distribution. Increasing the number of passes through the Microfluidizer, increasing the pressure, or reducing the phospholipid concentration all resulted in a smaller average liposome diameter. Changing these variables did not have a significant effect on the polydispersity of the dispersion. Electron microscopy showed that the dispersions formed had a range of structures, including unilamellar, multilamellar, and multivesicular liposomes. The composition of the MFGM phospholipid material is different from that of the phospholipids usually used for liposome production in the pharmaceutical and cosmetic industries. The MFGM-derived fraction comprises approximately 25% sphingomyelin, and the fatty acids are primarily saturated and monounsaturated. These differences are likely to affect the properties of the liposomes produced from the phospholipid material, and it may be possible to exploit the unique composition of the MFGM phospholipid fraction in the delivery of bioactive ingredients in functional foods.

Determination of the Neutron Lifetime Using Magnetically Trapped Neutrons

We report progress on an experiment to measure the neutron lifetime using magnetically trapped neutrons. Neutrons are loaded into a 1.1 T deep superconducting Ioffe-type trap by scattering 0.89 nm neutrons in isotopically pure superfluid (4)He. Neutron decays are detected in real time using the scintillation light produced in the helium by the beta-decay electrons. The measured trap lifetime at a helium temperature of 300 mK and with no ameliorative magnetic ramping is substantially shorter than the free neutron lifetime. This is attributed to the presence of neutrons with energies higher than the magnetic potential of the trap. Magnetic field ramping is implemented to eliminate these neutrons, resulting in an [Formula: see text] trap lifetime, consistent with the currently accepted value of the free neutron lifetime.

Proposed Measurement of the Beta-Neutrino Correlation in Neutron Decay

Currently, the beta-neutrino asymmetry has the largest uncertainty (4 %) of the neutron decay angular correlations. Without requiring polarimetry this decay parameter can be used to measure λ (ga/gv ), test Cabibbo-Kobayashi-Maskawa (CKM) unitarity limit scalar and tensor currents, and search for Charged Vector Current (CVC) violation. We propose to measure the beta-neutrino asymmetry coeffcient, a, using time-of-flight for the recoil protons. We hope to achieve a systematic uncertainty of σa / a ≈ 1.0 %. After tests at Indiana University's Low Energy Neutron Source (LENS), the apparatus will be moved to the National Institute of Standards and Technology (NIST) where the measurement can achieve a statistical uncertainty of 1 % to 2 % in about 200 beam days.

Detecting the Radiative Decay Mode of the Neutron

Beta decay of the neutron into a proton, electron, and electron antineutrino is occasionally accompanied by the emission of a photon. Despite decades of detailed experimental studies of neutron beta-decay, this rare branch of a fundamental weak decay has never been observed. An experiment to study the radiative beta-decay of the neutron is currently being developed for the NG-6 fundamental physics endstation at the National Institute of Standards and Technology (NIST) Center for Neutron Research (NCNR). The experiment will make use of the existing apparatus for the NIST proton-trap lifetime experiment, which can provide substantial background reduction by providing an electron-proton coincidence trigger. Tests and design of a detector for gamma-rays in the 10 keV to 200 keV range are under development. The need for a large solid-angle gamma-ray detector that can operate in a strong magnetic field and at low temperature has led us to consider scintillating crystals in conjunction with avalanche photodiodes. The motivation and experimental technique will be discussed.

A Backscatter Suppressed Electron Detector for the Measurement of "a"

A new method of measuring the electron-antineutrino angular correlation coefficient, little "a", from neutron decay-to be performed at the National Institute of Standards and Technology-will require an electron spectrometer that strongly suppresses backscattered electrons. A prototype consisting of six trapezoidal veto detectors arranged around a plastic scintillator has been tested with an electron beam produced by a Van de Graaff accelerator. The results of this test and its implications for the little "a" measurement are discussed.

The Fundamental Neutron Physics Facilities at NIST

The program in fundamental neutron physics at the National Institute of Standards and Technology (NIST) began nearly two decades ago. The Neutron Interactions and Dosimetry Group currently maintains four neutron beam lines dedicated to studies of fundamental neutron interactions. The neutrons are provided by the NIST Center for Neutron Research, a national user facility for studies that include condensed matter physics, materials science, nuclear chemistry, and biological science. The beam lines for fundamental physics experiments include a high-intensity polychromatic beam, a 0.496 nm monochromatic beam, a 0.89 nm monochromatic beam, and a neutron interferometer and optics facility. This paper discusses some of the parameters of the beam lines along with brief presentations of some of the experiments performed at the facilities.

Can the standard gamble and rating scale be used to measure quality of life in rhinoconjunctivitis? Comparison with the RQLQ and SF-36

BACKGROUND

With interest in health economics growing, it is important to know whether utilities may be used to measure health-related quality of life in patients with rhinoconjunctivitis. The objective was to compare the validity and measurement properties of disease-specific versions of the standard gamble and rating scale with those of the Rhinoconjunctivitis Quality of Life Questionnaire (RQLQ) and the Short-Form 36 (SF-36).

METHODS

One hundred adults with symptomatic rhinoconjunctivitis participated in a 5 week observational study, completing the standard gamble, rating scale, RQLQ and SF-36 at baseline and after 1 and 5 weeks. Symptom diaries were completed for 1 week before each follow-up visit.

RESULTS

Reliability was highest for the RQLQ (intraclass correlation coefficient = 0.97), followed by the rating scale (0.75), the SF-36 physical (0.75), the SF-36 mental (0.74) and the standard gamble (0.12). The responsiveness index was highest for the RQLQ (0.76), followed by the rating scale (0.56) and the SF-36 mental (0.28). Both cross-sectional and longitudinal validity were strongest for the RQLQ and the rating scale.

CONCLUSIONS

Both the rating scale and the RQLQ have strong evaluative and discriminative properties. The SF-36 has acceptable discriminative properties but its evaluative properties are poor. All measurement properties for the standard gamble are inadequate. Poor correlation between the standard gamble and the rating scale indicates that utilities cannot be derived from rating scale data.

Quality of life in patients with allergic rhinitis

LEARNING OBJECTIVES

Reading this article will familiarize the practitioner with ongoing efforts to measure the effects of allergic rhinitis symptoms and its treatments on the health-related quality of life (HRQOL) of patients. The reader will learn about instruments used to collect HRQOL data, results of studies showing the burden of illness and the effects of treatments on HRQOL, and efforts to interpret the clinical relevance of changes in HRQOL status.

DATA SOURCES

Information was gleaned from articles listed in MEDLINE regarding HRQOL in allergic rhinitis between 1966 and 2000 (English language only), and from the personal experiences of the authors.

STUDY SELECTION

Questionnaire validation studies and representative controlled trials employing measures to assess the effects of allergic rhinitis symptoms and its treatments on HRQOL are described. RESULTS FROM THIS REVIEW: Allergic rhinitis symptoms can have detrimental effects on the physical, psychologic, and social aspects of patients' lives. Clinical trial data suggest a variety of pharmacologic therapies can significantly improve HRQOL in patients with allergic rhinitis. Validated questionnaires are now available that can easily be used in clinical practice to measure the effects of interventions on HRQOL for individual patients.

CONCLUSIONS

Evaluating the effects of interventions on HRQOL may be particularly important in a non-life-threatening condition such as rhinitis. Health-related quality of life measures can be used to indicate the risk/benefit and the cost/benefit ratios of competing treatment options. Clinicians and policy makers are already using HRQOL data to evaluate results of medical interventions to guide patient management and reimbursement decisions.

Effect of 60 mg twice-daily fexofenadine HCl on quality of life, work and classroom productivity, and regular activity in patients with chronic idiopathic urticaria

The effect of 60 mg twice-daily fexofenadine HCl on health-related quality of life and productivity at work, in the classroom, and during daily activities in patients with moderate to severe chronic idiopathic urticaria symptoms was studied in two identical, 4-week, placebo-controlled, multicenter clinical trials. Patients self-administered the Dermatology Life Quality Index (score, 0-30) and the Work Productivity and Activity Impairment instrument (0%-100%). In both trials, improvements in Dermatology Life Quality Index scores in fexofenadine-treated patients (N = 169) were statistically significant compared with placebo (P < or =.0002). Similarly, improvements in productivity scores with fexofenadine 60 mg twice daily were statistically superior to placebo at work (n = 120, P < or =.0152) and in performance of daily activities (n = 166, P < or =.0002). There was a trend toward improved classroom productivity (n = 26) with fexofenadine. We conclude fexofenadine 60 mg twice daily improves health-related quality of life, increases work productivity, and improves performance of daily activities in patients with moderate to severe chronic idiopathic urticaria.

Demonstration of a compact compressor for application of metastability-exchange optical pumping of 3He to human lung imaging

Hyperpolarized gas magnetic resonance imaging has recently emerged as a method to image lungs, sinuses, and the brain. The best lung images to date have been produced using hyperpolarized 3He, which is produced by either spin-exchange or metastability-exchange optical pumping. For hyperpolarized gas MRI, the metastable method has demonstrated higher polarization levels and higher polarizing rates, but it requires compression of the hyperpolarized gas. Prior to this work, compression of hyperpolarized gas had only been accomplished using a large, complex and expensive apparatus. Here, human lung ventilation images are presented that were obtained using a compact compressor that is relatively simple and inexpensive. For this test, 1.1 bar-L of 15% hyperpolarized 3He gas was produced at the National Institute of Standards and Technology using a modified commercial diaphragm pump. The hyperpolarized gas was transported to the University of Pennsylvania in a holding field provided by a portable solenoid.

Development and validation of the mini Rhinoconjunctivitis Quality of Life Questionnaire

BACKGROUND

The 28-item Rhinoconjunctivitis Quality of Life Questionnaire (RQLQ) has strong measurement properties but for large clinical trials, surveys and practice monitoring, where high efficiency is important, a shorter questionnaire is needed.

OBJECTIVE

To develop and validate an abbreviated version of the RQLQ.

METHODS

Using five RQLQ databases, items with high item-item correlations were combined and then the highest scoring items were selected for the MiniRQLQ (14 questions). There are five domains: activity limitations (standardized), practical problems and nose symptoms, eye symptoms and other symptoms. The MiniRQLQ, which is self-administered, was tested in a 5-week observational study in 100 adults with symptomatic rhinoconjunctivitis. Patients completed the MiniRQLQ, the RQLQ, and other measures of health status at baseline, 1 and 5 weeks.

RESULTS

In patients whose rhinoconjunctivitis was stable between clinic visits, reliability (reproducibility and ability to discriminate between patients of different impairment) was very acceptable for the MiniRQLQ (ICC = 0.93) but not quite as good as for the RQLQ (ICC = 0.97). Responsiveness to change in clinical status was better with the MiniRQLQ than the RQLQ (P = 0. 044). Construct validity (correlation with other indices of health status) was strong for both the MiniRQLQ and the RQLQ. Concordance between the two instruments was high (ICC = 0.87).

CONCLUSIONS

The MiniRQLQ has strong measurement properties and measures the same construct as the original RQLQ. The choice of questionnaire should depend on the task at hand.

Once-daily fexofenadine HCl improves quality of life and reduces work and activity impairment in patients with seasonal allergic rhinitis

BACKGROUND

Fexofenadine HCl (Allegra, Telfast) is approved in the US for twice-daily dosing for treatment of seasonal allergic rhinitis.

OBJECTIVE

To determine the effect of once-daily fexofenadine HCl on patient-reported quality of life and impairment at work, in the classroom, and in daily activities due to seasonal allergic rhinitis symptoms.

METHODS

This placebo-controlled, double-blind, randomized study included patients aged 12 to 65 years with moderate-to-severe seasonal allergic rhinitis symptoms. Outcomes were assessed using self-administered questionnaires at baseline, week 1, and week 2. Outcome measures included change from baseline in: overall Rhinoconjunctivitis Quality of Life Questionnaire (RQLQ) score; individual RQLQ domain scores; work, classroom, and daily activity impairment measured using the Work Productivity and Activity Impairment (WPAI) instrument; and ratings in 3 generic health domains from the SF-36 Health Survey.

RESULTS

Intent to treat efficacy analyses included 845 patients from 40 sites. Patients receiving either 120 or 180 mg QD fexofenadine HCl reported significantly greater improvement (P < or = .006) in overall RQLQ score than patients receiving placebo. Similarly, both fexofenadine treatment groups reported significantly greater reductions in overall work impairment and daily activity impairment compared with the placebo group (P < or = .004). There was a trend for improvement in classroom impairment with fexofenadine treatment, although differences from placebo were not statistically significant. Generic health measures demonstrated fexofenadine HCl treatment had a positive effect on general health.

CONCLUSION

Once-daily fexofenadine HCl, 120 or 180 mg, significantly improved patient-reported quality of life and reduced performance impairment in work and daily activities due to seasonal allergic rhinitis symptoms compared with placebo.

Validation of the standardized version of the Rhinoconjunctivitis Quality of Life Questionnaire

BACKGROUND

In the Rhinoconjunctivitis Quality of Life Questionnaire (RQLQ), the 3 activity questions are selected by the patients themselves. For greater efficiency, a version with standardized activities is required.

OBJECTIVE

Our purpose was to develop and validate a standardized version of the RQLQ, the RQLQ(S).

METHODS

With use of 5 RQLQ databases, we identified the activities most frequently selected by patients and formulated 3 generic questions that would encompass the majority of these activities. The RQLQ(S) was tested in a 5-week observational study in 100 adults with symptomatic rhinoconjunctivitis. Patients completed the RQLQ(S), the RQLQ, and other measures of health status at baseline and 1 and 5 weeks.

RESULTS

The activity domain of the RQLQ(S) consistently gave lower scores than did the activity domain of the RQLQ (P <.001). However, this made very little difference to the overall scores (RQLQ[S] = 2.36 +/- 1.23, RQLQ = 2.43 +/- 1.23), and overall concordance was high (intraclass correlation coefficient = 0.996). In patients whose rhinoconjunctivitis was stable between clinic visits, reliability (reproducibility and ability to discriminate between patients of different impairment) was high for both instruments and almost identical (intraclass correlation coefficient = 0.97). Responsiveness to change was also very similar and good (P <.001). Construct validity (correlation with other index values of health status) was strong for both the RQLQ(S) and the RQLQ.

CONCLUSIONS

The RQLQ(S) has strong measurement properties and measures the same construct as the original RQLQ. The choice of questionnaire should depend on the task at hand.

Measuring quality of life in children with rhinoconjunctivitis

OBJECTIVE

The objective of this study was to develop, pretest, and validate a questionnaire to measure quality of life in children with seasonal allergic rhinoconjunctivitis (SAR).

METHODS (DEVELOPMENT STUDY)

Thirty-four children with SAR were enrolled from summer camps, notices in the media, and an allergy clinic (Southern Ontario). After generating a pool of 48 potentially important quality of life items, the children identified the ones that they experienced with their SAR and scored each for bother (1 = a little bothered to 4 = extremely bothered). Items identified most frequently and with the highest bother score were included in the Paediatric Rhinoconjunctivitis Quality of Life Questionnaire (PRQLQ). The PRQLQ was pretested for ease completion and accuracy of understanding.

RESULTS (DEVELOPMENT STUDY)

The PRQLQ has 23 items in five domains (nose symptoms, eye symptoms, practical problems, other symptoms, and activities). Responses are given on a seven-point scale, and children are asked to score their experiences during the previous 7 days.

METHODS (VALIDATION STUDY)

Seventy-five children with symptomatic SAR were enrolled from notices in the media and a pediatric allergy clinic (Austin, Tex.). A single cohort design was used, with children assessed at 0, 1, and 3 weeks. The PRQLQ was administered to the children by a trained interviewer at 1 and 3 weeks. A conventional nasal symptom daily diary was completed for 1 week before each of these clinic visits. Global ratings were completed at the final visit.

RESULTS (VALIDATION STUDY)

In patients who were stable between clinic visits, the PRQLQ demonstrated good reliability (intraclass correlation coefficient = 0.93). The questionnaire was very responsive to change (p < 0.001) and was able to differentiate between patients who were in a stable clinical state and those whose clinical state changed between visits (p = 0.005). Correlations between the PRQLQ and diary scores were close to predicted and supported both the cross-sectional and longitudinal validity of the PRQLQ.

CONCLUSIONS

The PRQLQ measures the quality of life impairments important to children with SAR. Children provide reliable and accurate responses, the measurement properties are strong, and the questionnaire can be used with confidence in clinical trials, clinical practice, and surveys.

The Short Inflammatory Bowel Disease Questionnaire: a quality of life instrument for community physicians managing inflammatory bowel disease. CCRPT Investigators. Canadian Crohn's Relapse Prevention Trial

OBJECTIVE

Health-related quality of life (HRQOL) affects outcome in chronic diseases such as inflammatory bowel disease (IBD). The inflammatory bowel disease questionnaire (IBDQ), a disease-specific HRQOL questionnaire, can define changes in health status in IBD, but simple instruments are needed for daily application. The present study proposed to develop a short version of the IBDQ, the SIBDQ, for community physicians.

METHODS

Using data from a clinical trial in 149 patients with Crohn's disease, 10 items were selected (by forward stepwise regression) that best explained the variance of the IBDQ or dimensional scores (bowel, systemic, social, emotional). The validity, reliability, and responsiveness of the SIBDQ were then assessed in 150 different patients with Crohn's disease and 45 with ulcerative colitis. All scores were reported with a 7-point scale (1 = poor HRQOL, 7 = optimum HRQOL).

RESULTS

Mean SIBDQ scores were similar (p = 0.22) in Crohn's patients among 14 participating centers at study entry. Mean scores were lower in active Crohn's disease (range 4.00-4.92) than inactive disease (range 4.67-5.83; p = 0.0015). In active ulcerative colitis, the mean SIBDQ was 4.79 +/- 1.17 compared to 5.90 +/- 0.80 (p = 0.0006) in inactive disease. The SIBDQ explained 92% and 90% of the IBDQ variance in Crohn's disease and ulcerative colitis, respectively. In patients with stable Crohn's disease, the test-retest reliability coefficient was 0.65 and Crohnbach's alpha was 0.78, indicating good reliability. In patients with Crohn's disease who relapsed during follow-up, the mean SIBDQ decreased by -0.93 + 0.55 (p = 0.001).

CONCLUSION

The SIBDQ is valid, reliable, and able to detect meaningful clinical changes in HRQOL that might occur in the office setting.

Squamous cell carcinoma of the gallbladder presenting with a biliary-colic fistula

Pure squamous carcinoma of the gall bladder is a rare tumour which may present diagnostic difficulty for the histopathologist. A case presenting as a biliary-colic fistula is described and the diagnostic histological features discussed. Theories regarding aetiology and the prognosis of this rare tumour are also discussed.

Regulation of NMDA receptor phosphorylation by alternative splicing of the C-terminal domain

The NMDA (N-methyl D-aspartate) receptors in the brain play a critical role in synaptic plasticity, synaptogenesis and excitotoxicity. Molecular cloning has demonstrated that NMDA receptors consist of several homologous subunits (NMDAR1, 2A-2D). A variety of studies have suggested that protein phosphorylation of NMDA receptors may regulate their function and play a role in many forms of synaptic plasticity such as long-term potentiation. We have examined the phosphorylation of the NMDA receptor subunit NMDAR1 (NR1) by protein kinase C (PKC) in cells transiently expressing recombinant NR1 and in primary cultures of cortical neurons. PKC phosphorylation occurs on several distinct sites on the NR1 subunit. Most of these sites are contained within a single alternatively spliced exon in the C-terminal domain, which has previously been proposed to be on the extracellular side of the membrane. These results demonstrate that alternative splicing of the NR1 messenger RNA regulates its phosphorylation by PKC, and that mRNA splicing is a novel mechanism for regulating the sensitivity of glutamate receptors to protein phosphorylation. These results also provide evidence that the C-terminal domain of the NR1 protein is located intracellularly, suggesting that the proposed transmembrane topology model for glutamate receptors may be incorrect.

Contribution of G protein activation to fluoride stimulation of phosphoinositide hydrolysis in human neuroblastoma cells

To examine the possibility that NaF enhances phosphoinositide-specific phospholipase C (PIC) activity in neural tissues by a mechanism independent of a guanine nucleotide binding protein (Gp), we have evaluated the contribution of Gp activation to NaF-stimulated phosphoinositide hydrolysis in human SK-N-SH neuroblastoma cells. Addition of NaF to intact cells resulted in an increase in the release of inositol phosphates (450% of control values; EC50 of approximately 8 mM). Inclusion of U-73122, an aminosteroid inhibitor of guanine nucleotide-regulated PIC activity in these cells, resulted in a dose-dependent inhibition of NaF-stimulated inositol lipid hydrolysis (IC50 of approximately 3.5 microM). When added to digitonin-permeabilized cells, NaF or guanosine-5'-O-thiotriphosphate (GTP gamma S) resulted in a three- and sevenfold enhancement, respectively, of inositol phosphate release. In the combined presence of optimal concentrations of NaF and GTP gamma S, inositol phosphate release was less than additive, indicative of a common site of action. Inclusion of 2-5 mM concentrations of guanosine-5'-O-(2-thiodiphosphate) (GDP beta S) fully blocked phosphoinositide hydrolysis elicited by GTP gamma S, whereas that induced by NaF was partially inhibited (65%). However, preincubation of the cells with GDP beta S resulted in a greater reduction in the ability of NaF to stimulate inositol phosphate release (87% inhibition). Both GTP gamma S and NaF-stimulated inositol phosphate release were inhibited by inclusion of 10 microM U-73122 (54-71%). The presence of either NaF or GTP gamma S also resulted in a marked lowering of the Ca2+ requirement for activation of PIC in permeabilized cells. These results indicate that in SK-N-SH cells, little evidence exists for direct stimulation of PIC by NaF and that the majority of inositol phosphate release that occurs in the presence of NaF can be attributed to activation of Gp.

The aminosteroid U-73122 inhibits muscarinic receptor sequestration and phosphoinositide hydrolysis in SK-N-SH neuroblastoma cells. A role for Gp in receptor compartmentation

The relationship between muscarinic receptor activation of phosphoinositide hydrolysis and the sequestration of cell surface muscarinic receptors has been examined for both intact and digitonin-permeabilized human SK-N-SH neuroblastoma cells. Addition of the aminosteroid 1-[6-[[17 beta-3-methoxyestra-1,3,5(10)-trien-17-yl]amino] hexyl]-1H-pyrrole-2,5-dione (U-73122) to intact cells resulted in the inhibition of oxotremorine-M-stimulated inositol phosphate release and of Ca2+ signaling by greater than 75%. In contrast, when phospholipase C was directly activated by the addition of the calcium ionophore ionomycin, inclusion of U-73122 had little inhibitory effect. Addition of U-73122 to intact cells also inhibited the agonist-induced sequestration of cell surface muscarinic receptors and their subsequent down-regulation with an IC50 value (4.1 microM) similar to that observed for inhibition of inositol phosphate release (3.7 microM). In contrast, when oxotremorine-M-stimulated phosphoinositide hydrolysis was inhibited by depletion of extracellular Ca2+, no reduction in the extent of receptor sequestration was observed. When introduced into digitonin-permeabilized cells, U-73122 more markedly inhibited inositol phosphate release elicited by either oxotremorine-M or guanosine-5'-O-(3-thiotriphosphate) than that induced by added Ca2+. Addition of oxotremorine-M to permeabilized cells resulted in muscarinic receptor sequestration and down-regulation. Both the loss of muscarinic acetylcholine receptors and activation of phosphoinositide hydrolysis in permeabilized cells were inhibited by the inclusion of guanosine-5'-O-(2-thiodiphosphate). The results indicate that the agonist-induced sequestration of muscarinic acetylcholine receptor in SK-N-SH cells requires the involvement of a GTP-binding protein but not the production of phosphoinositide-derived second messenger molecules.

Preferential coupling of cell surface muscarinic receptors to phosphoinositide hydrolysis in human neuroblastoma cells

The ability of muscarinic receptors, present in either the cell surface or sequestered compartments of intact human SK-N-SH neuroblastoma cells, to stimulate phosphoinositide hydrolysis has been examined. When cells were first exposed to carbachol for 1 h at 37 degrees C, approximately 50% of the cell surface receptors became sequestered, and this was accompanied by a comparable reduction in the subsequent ability of muscarinic agonists to stimulate phosphoinositide turnover, as monitored by the release of labeled inositol phosphates at 10 degrees C. At this temperature, muscarinic receptor cycling between the two cell compartments is prevented. Upon warming the carbachol-pretreated cells to 37 degrees C, receptor cycling is reinitiated and stimulated phosphoinositide turnover is fully restored within 5-8 min. When measured at 10 degrees C, the reduction of stimulated phosphoinositide turnover observed following carbachol pretreatment was similar in magnitude for both hydrophilic (carbachol, oxotremorine-M) and lipophilic (arecoline, oxotremorine-2, and L-670,548) agonists. The loss of response for both groups of agonists could be prevented if the incubation temperature was maintained at 37 degrees C, rather than at 10 degrees C. At the latter temperature carbachol pretreatment of SK-N-SH cells reduced the maximum release of inositol phosphates elicited by either carbachol or L-670,548 but not the agonist concentrations required for half-maximal stimulation. Radioligand binding studies, carried out at 10 degrees C, indicate that following receptor sequestration, significantly higher concentrations of carbachol were required to occupy the available muscarinic receptor sites. In contrast the lipophilic full agonist L-670,548 recognized receptors present in control and carbachol-pretreated cells with comparable affinities. Analysis of the inositol lipids present after carbachol pretreatment indicate that only a minimal depletion of the substrates necessary for phospholipase C activation had occurred. The results indicate that the agonist-induced sequestration of muscarinic receptors from the cell surface results in a loss of stimulated phosphoinositide hydrolysis when measured under conditions in which the return of the sequestered receptors to the cell surface is prevented. Thus, only those receptors present at the cell surface are linked to phospholipase C activation.

Relationship between agonist-induced muscarinic receptor loss and desensitization of stimulated phosphoinositide turnover in two neuroblastomas: methodological considerations

The addition of both full and partial muscarinic agonists to human SK-N-SH neuroblastoma cells resulted in a sustained phosphoinositide (PPI) hydrolysis for up to 2 hr, as monitored either by the accumulation of [3H]inositol phosphates (IP) in the presence of Li+, or alternatively, by an increased labeling of phosphatidate and phosphatidylinositol (PI) from 32Pi. This enhanced PPI hydrolysis was maintained even though 40-50% of cell-surface muscarinic cholinergic receptors (mAChRs) became sequestered. Desensitization of carbachol-stimulated PPI hydrolysis was only detected after a 2-4 hr prior exposure of the cells to the agonist and was accompanied by a comparable reduction in total mAChR number. Prolonged incubation of SK-N-SH cells with the partial agonist bethanechol also resulted in a desensitization of stimulated PPI turnover but at a slower rate than that observed for carbachol and with a loss of fewer mAChR sites. Desensitization of mAChR-stimulated [3H]IP formation appeared to occur more rapidly in mouse NIE-115 neuroblastoma. However, Li+ could not fully prevent the degradation of accumulated [3H]IP in these cells. When an increase in [32P]phosphatidylinositol labeling was used to assess PPI turnover in NIE-115 cells, no desensitization was evident for up to 2 hr. We conclude that 1) in SK-N-SH cells, desensitization more closely parallels the down-regulation than the sequestration of mAChRs, 2) in both neuroblastomas, stimulated PPI hydrolysis desensitizes relatively slowly and 3) the appearance of desensitization can vary as a function of the assay method employed.

A case of Dipylidium caninum in Baton Rouge, Louisiana

The relevant literature concerning human dipylidiasis has been reviewed with specific reference to the association of children and their pet dog and cats. A specific case is recounted which is considered to be typical of the condition as encountered by pediatricians and general practitioners.

Salt tolerance in cultured cells of Spartina pectinata

Suspension cultures with cell doubling times of ca. 2 days were developed from the halophytic grass Spartina pectinata. Maximum rates of exponential growth measured by direct cell counts and by total culture packed-cell-volume were not significantly reduced by NaCl up to 200 mM but dropped beyond this point. In contrast, total cell production over a one week culture cycle, by both measures, was reduced in a roughly linear fashion between 0 and 500 mM NaCl. The pattern of growth in relation to NaCl is very similar to that of previously described cell suspensions derived from another halophyte, Distichlis spicata. In the field the latter is much more salt tolerant. The basis for the whole plant differences is not clear. They do not appear to reflect effectiveness of cell based salt tolerance or the presence of salt glands, which are reported here for the first time in S. pectinata and are found on the leaves of both species.

A clinical rating scale of speech dysfunction in Parkinson's disease

The speech dysfunction of Parkinson's disease is complex and individually variable owing to the interaction of muscle rigidity, tremor and disturbance of movement. Eight speech dimensions which are characteristically disturbed in Parkinson's disease are discussed with reference to available research findings. In order to provide a more detailed description of the speech than could be obtained by clinical notes alone, a speech rating scale has been developed, and is presented in summarized form for clinical use. Incidence and progression of the speech dysfunction are considered in addition to the problems of assessment peculiar to the patient with Parkinson's disease.