Glial cells in (patho)physiology

Neuroglial cells define brain homeostasis and mount defense against pathological insults. Astroglia regulate neurogenesis and development of brain circuits. In the adult brain, astrocytes enter into intimate dynamic relationship with neurons, especially at synaptic sites where they functionally form the tripartite synapse. At these sites, astrocytes regulate ion and neurotransmitter homeostasis, metabolically support neurons and monitor synaptic activity; one of the readouts of the latter manifests in astrocytic intracellular Ca(2+) signals. This form of astrocytic excitability can lead to release of chemical transmitters via Ca(2+) -dependent exocytosis. Once in the extracellular space, gliotransmitters can modulate synaptic plasticity and cause changes in behavior. Besides these physiological tasks, astrocytes are fundamental for progression and outcome of neurological diseases. In Alzheimer's disease, for example, astrocytes may contribute to the etiology of this disorder. Highly lethal glial-derived tumors use signaling trickery to coerce normal brain cells to assist tumor invasiveness. This review not only sheds new light on the brain operation in health and disease, but also points to many unknowns.

Prophylactic cranial irradiation is indicated following complete response to induction therapy in small cell lung cancer: results of a multicentre randomised trial. United Kingdom Coordinating Committee for Cancer Research (UKCCCR) and the European Organization for Research and Treatment of Cancer (EORTC)

Prophylactic cranial irradiation (PCI) reduces the risk of cranial metastasis in small cell lung cancer (SCLC), but the magnitude and value of this reduction, the risks of radiation morbidity and whether PCI influences survival are unclear. We conducted a randomised trial in patients with limited-stage SCLC who had had a complete response to induction therapy. Initially, patients were randomised equally to (1) PCI 36 Gy in 18 daily fractions, (2) PCI 24 Gy in 12 fractions and (3) no PCI; subsequently, to increase the rate of accrual, randomisation was to clinicians' choice of PCI regimen versus no PCI (at a 3:2 ratio). The endpoints were appearance of brain metastases, survival, cognitive function, and quality of life (QoL). Three hundred and fourteen patients (194 PCI, 120 No PCI) were randomised. In the revised design, the most commonly used PCI regimens were 30 Gy in 10 fractions and 8 Gy in a single dose. With PCI, there was a large and highly significant reduction in brain metastases (HR = 0.44, 95% CI 0.29-0.67), a significant advantage in brain-metastasis-free survival (HR = 0.75, 95% CI 0.58-0.96) and a non-significant overall survival advantage (HR = 0.86, 95% CI 0.66-1.12). In both groups, there was impairment of cognitive function and QoL before PCI and additional impairment at 6 months and 1 year, but no consistent difference between the two groups and thus no evidence over 1 year of major impairment attributable to PCI. PCI can safely reduce the risk of brain metastases. Further research is needed to define optimal dose and fractionation and to clarify the effect on survival. Patients with SCLC achieving a complete response to induction therapy should be offered PCI.

Particulate air pollution and the blood

BACKGROUND

Particulate air pollution has been associated with excess deaths from, and increases in hospital admissions for, cardiovascular disease among older people. A study was undertaken to determine whether this may be a consequence of alterations in the blood, secondary to pulmonary inflammation caused by the action of fine particles on alveolar cells, by repeatedly measuring haematological factors in older people and relating them to measurements of exposure to airborne particles.

METHODS

One hundred and twelve individuals aged 60+ years in two UK cities provided repeated blood samples over 18 months, 108 providing the maximum of 12 samples. Estimates of individual exposure to particles of less than 10 microm diameter (PM(10)), derived from a mathematical model based on activity diaries and comparative measurements of PM(10) at multiple sites and during a variety of activities, were made for each three day period prior to blood sampling. The relationships between blood values and estimates of both personal exposure and city centre measurements of PM(10) were investigated by analysis of covariance, adjusting for city, season, temperature, and repeated individual measurements.

RESULTS

Estimated personal exposure to PM(10) over the previous three days showed negative correlations with haemoglobin concentration, packed cell volume (PCV), and red blood cell count (p<0.001), and with platelets and factor VII levels (p<0.05). The changes in red cell indices persisted after adjustment for plasma albumin in a sample of 60 of the subjects. City centre PM(10) measurements over three days also showed negative correlations with haemoglobin and red cell count (p<0.001) and with PCV and fibrinogen (p<0.05), the relationship with haemoglobin persisting after adjustment for albumin. C reactive protein levels showed a positive association with city centre measurements of PM(10) (p<0.01). Based on a linear relationship, the estimated change in haemoglobin associated with an alteration in particle concentration of 100 microg/m(3) is estimated to have been 0.44 g/dl (95% CI 0.62 to 0.26) for personal PM(10) and 0.73 g/dl (95% CI 1.11 to 0.36) for city centre PM(10) measurements.

CONCLUSIONS

This investigation is the first to estimate personal exposures to PM(10) and to demonstrate associations between haematological indices and air pollution. The changes in haemoglobin adjusted for albumin suggest that inhalation of some component of PM(10) may cause sequestration of red cells in the circulation. We propose that an action of such particles either on lung endothelial cells or on erythrocytes themselves may be responsible for changing red cell adhesiveness. Peripheral sequestration of red cells offers an explanation for the observed cardiovascular effects of particulate air pollution.

Induction of CD4(+) T cell-dependent CD8(+) type 1 responses in humans by a malaria DNA vaccine

We assessed immunogenicity of a malaria DNA vaccine administered by needle i.m. or needleless jet injection [i.m. or i.m./intradermally (i.d.)] in 14 volunteers. Antigen-specific IFN-gamma responses were detected by enzyme-linked immunospot (ELISPOT) assays in all subjects to multiple 9- to 23-aa peptides containing class I and/or class II restricted epitopes, and were dependent on both CD8(+) and CD4(+) T cells. Overall, frequency of response was significantly greater after i.m. jet injection. CD8(+)-dependent cytotoxic T lymphocytes (CTL) were detected in 8/14 volunteers. Demonstration in humans of elicitation of the class I restricted IFN-gamma responses we believe necessary for protection against the liver stage of malaria parasites brings us closer to an effective malaria vaccine.

PTSD substance abuse comorbidity and treatment utilization

The present study investigates the prevalence of posttraumatic stress disorder (PTSD) among a sample of treatment-seeking substance abusers and examines the relationship between PTSD comorbidity and rates of inpatient substance abuse treatment. Eighty-four patients (48 male and 36 female) admitted for detoxification at a private hospital were administered self-report measures of lifetime stressor events, PTSD symptomatology, and prior treatment history. Approximately one quarter of the sample was found to present with significant PTSD symptomatology. Women were more likely than men to have been physically and sexually abused, and women reported experiencing a greater number of traumatic events. Consequently, more women than men were classified as having possible PTSD. With respect to inpatient substance abuse treatment admission rates, the PTSD group reported a greater number of hospitalizations than their non-PTSD counterparts. Implications of these findings for routine trauma screening and more effective treatment for substance abusers with concomitant PTSD are highlighted.

Selective sorption of bacteria from seawater

A sequence of sorption of different bacterial types has been observed both on glass slides and electron microscope grids immersed in seawater for periods of up to 24 h. A comparison of morphological groups of bacteria initially attracted to a surface with those subsequently adhering firmly to the surface suggests a selective irreversible sorption of small rods. Firm adhesion of bacteria in the time periods considered does not indicate pili or holdfast structures. The ability of bacteria to produce extracellular polymeric fibrils may be important in such selective sorption.

The effect of social investment on treatment outcome

Social support is associated with better response to treatment. Treatments focused on relationships, such as marital and family therapy, are directed in part at promoting this support. However, the strength of the relationship between support and abstinence is modest, as is the demonstrated incremental effectiveness of treatments focused on relationships. Treatment-matching research needs to determine under what set of conditions treatments focused on relationships will enhance abstinence. The primary aim of this study was to determine whether the relationship between alcohol involvement and alcohol-specific social support is moderated by a person's social investment. The second aim was to determine the set of circumstances under which extended individually focused cognitive behavioral (CB) treatment and a relationship enhancement (RE) of brief cognitive behavioral treatments would improve outcomes. Patients were randomly assigned to individual or relationship-enhanced outpatient treatment and followed for 12 months. Results indicated that a patient's social investment did moderate the strength of the relationship between support and posttreatment alcohol involvement: Among high investors, there was a strong positive relationship, while the association was weak for low investors. A hypothesized triple-order interaction between social investment, posttreatment support and treatment did not materialize. However, an interaction between support and treatment showed that those with high support did equally well in either treatment, while those posttreatment support was low benefited from CB, but experienced poor outcomes when treated in relationship enhancement of CB. Further analyses indicated that increasing alcohol-specific support for low investors was probably contraindicated. We suggest that patients with low investment should be treated in an extended cognitive behavioral modality, while relationally enhanced CB treatment should be limited to high investors who are likely to experience support for their abstinence following treatment.

Effectiveness of three types of spouse-involved behavioral alcoholism treatment

Treatment was provided to 45 alcoholics and their spouses in one of three out-patient behavioral treatment conditions: (1) minimal spouse involvement (MSI) (n = 14), (2) alcohol-focused spouse involvement (AFSI) (n = 12), or (3) alcohol-focused spouse involvement plus behavioral marital therapy (ABMT) (n = 19). Subjects were followed for 18 months after treatment. Subjects in all conditions reported significant decreases in frequency of drinking and frequency of heavy drinking, and reported increased life satisfaction. This information was corroborated by independent reports of the spouses. Patterns of outcome varied across the three treatment conditions, with ABMT subjects showing gradual improvement in proportions of abstinent days and abstinent plus light drinking days over the last 9 months of follow-up. Subjects in the other two treatment conditions showed gradual deterioration in proportion of abstinent days and abstinent plus light drinking days. Subjects assigned to the ABMT condition were less likely to experience marital separations, and reported greater improvement in marital satisfaction and subjective well-being than the other experimental groups. Clinical and theoretical significance of these findings are discussed.

Connexins modulate autophagosome biogenesis

The plasma membrane contributes to the formation of autophagosomes, the double-membrane vesicles that sequester cytosolic cargo and deliver it to lysosomes for degradation during autophagy. In this study, we have identified a regulatory role for connexins (Cx), the main components of plasma membrane gap junctions, in autophagosome formation. We have found that plasma-membrane-localized Cx proteins constitutively downregulate autophagy through a direct interaction with several autophagy-related proteins involved in the initial steps of autophagosome formation, such as Atg16 and components of the PI(3)K autophagy initiation complex (Vps34, Beclin-1 and Vps15). On nutrient starvation, this inhibitory effect is released by the arrival of Atg14 to the Cx-Atg complex. This promotes the internalization of Cx-Atg along with Atg9, which is also recruited to the plasma membrane in response to starvation. Maturation of the Cx-containing pre-autophagosomes into autophagosomes leads to degradation of these endogenous inhibitors, allowing for sustained activation of autophagy.

Safety and immunogenicity of varying dosages of trivalent inactivated influenza vaccine administered by needle-free jet injectors

To evaluate the perceived pain, other adverse events, and immunogenicity of influenza virus vaccine administered by needle-free jet injector (JI) compared with that of vaccine administered by needle and syringe (N&S), we randomly assigned 304 healthy young adults to receive one of three dosages (0.5, 0.3, or 0.2 ml) of the 1998-1999 season vaccine administered by either of two JI devices or by N&S. In multivariate analysis, female gender and JI administration were associated with higher levels of pain reported at the time of vaccination as well as with the occurrence of local injection site reactions following vaccination. Immune response did not vary significantly by dosage but administration by one JI device was associated with higher post-vaccination H1N1 antibody titers.

Radical radiotherapy for carcinoma of the oesophagus: an effective alternative to surgery

BACKGROUND AND PURPOSE

Despite advances in operative and postoperative care, long term survival rates following radical oesophagectomy are poor. Surgery remains the mainstay of radical treatment despite various series reporting similar results for treatment with radiotherapy, in particular in the upper third of the oesophagus. We have studied a cohort of patients treated with definitive radiotherapy to examine the influence on survival of changes in diagnostic scanning and radiotherapy computer planning as well as various patient and disease related prognostic factors.

PATIENTS AND METHODS

From 1985 to 1994, 101 patients with clinically localised carcinoma of the oesophagus were treated at the Christie Hospital with definitive radiotherapy. This included 11 patients with oesophageal adenocarcinoma. Diagnostic and planning techniques changed over the period studied, with increasing use of both diagnostic and radiotherapy planning CT scanning. Radiotherapy doses ranged from 45 to 52.5 Gy in 15 or 16 fractions over 3 weeks.

RESULTS

The 3- and 5-year survival figures were 27% and 21%, respectively, corrected for intercurrent deaths. Survival was better for adenocarcinoma than squamous cell carcinoma, though not statistically significantly. The only significant prognostic factor (P = 0.01) was the use of diagnostic CT scanning (42% versus 13% 5-year survival with or without diagnostic CT scanning, respectively) which was associated with an increase in field size. Radiotherapy was well tolerated with no acute mortality or significant morbidity. Late stenosis requiring oesophageal was seen in five of 20 patients surviving 3 years or more.

CONCLUSIONS

Survival following well planned radiotherapy is an effective alternative to surgery for both squamous cell and adenocarcinoma. Advances in staging and three-dimensional planning and the use of multimodality treatment may further improve survival.

Matching treatment focus to patient social investment and support: 18-month follow-up results

Patients were randomly assigned to 1 of 3 treatments: brief broad-spectrum (BBS), extended relationship enhancement (ERE), or extended cognitive-behavioral (ECB). A hierarchical latent growth model was used to analyze the data of 188 patients (82%) followed for 18 months. ERE treatment was significantly more effective in increasing abstinence of patients entering treatment with a network unsupportive of abstinence or with a low level of investment in their network, whereas BBS treatment was more effective for patients with either (a) both a social network unsupportive of abstinence and a low level of network investment or (b) high investment in a network supportive of abstinence. ECB outcomes were neither as good as those matched nor as bad as those mismatched to the different exposures of relationship enhancement. This suggests that dose of relationship enhancement should be determined after assessing patient relationships.

Clinical and quality of life outcomes in the first United Kingdom randomized trial of endobronchial brachytherapy (intraluminal radiotherapy) vs. external beam radiotherapy in the palliative treatment of inoperable non-small cell lung cancer

BACKGROUND AND PURPOSE

A randomized controlled trial was designed to evaluate the clinical and quality of life (QL) outcomes of patients receiving endobronchial brachytherapy (EBT) or external beam radiotherapy (XRT) as a primary palliative treatment in advanced lung cancer.

MATERIALS AND METHODS

Ninety-nine patients presenting de novo with lung cancer were randomized to receive EBT or XRT. Eleven key symptoms or clinical signs were assessed by clinicians and patient ratings using self-assessment questionnaires were obtained at the same time. The primary endpoints were a comparison of EBT and XRT for symptom relief and acute and late side-effects (palliation) and their effect on patients' functional status and patient-rated QL outcomes. A secondary objective was a comparison of clinician assessments with patient self-reported symptoms.

RESULTS

Both treatments produced good levels of symptom relief. They were better for XRT at the expense of more acute morbidity. Late side-effects were similar. The functional status of patients was well maintained and changed similarly with time in both groups. XRT gave a better duration of palliation. Twenty-eight percent of XRT patients required EBT (at a median time of 304 days) whereas 51% of EBT patients subsequently had XRT (at a median of 125 days). There was a significant modest gain in median survival with initial XRT (287 vs. 250 days). When clinician and patient assessments were compared, doctors were found to underestimate the severity of breathlessness, anorexia, tiredness and nausea.

CONCLUSIONS

Fractionated XRT is preferred to EBT as an initial treatment in better performance patients because it provides better overall and more sustained palliation with fewer retreatments and a modest gain in survival time. QL assessment is required in the evaluation of palliative treatments because clinicians frequently underestimate the incidence and severity of key symptoms.

Neurological and cognitive impairment in long-term survivors of small cell lung cancer

Despite its effectiveness in reducing the rate of brain metastases, the role of prophylactic cranial irradiation (PCI) in the management of small cell lung cancer (SCLC) remains controversial because of concern about radiation-induced neurological morbidity. In order to evaluate morbidity and its impact on quality of life 64 patients surviving > or = 2 years in remission were recalled for assessment. 52 had received PCI. Most of the patients were well: 95% had performance status < or = 1 and nine out of 37 neurological examinations were abnormal. On neuropsychometric testing, only 19% of patients performed at the level expected for their age and intellectual ability on all four tests used. Fifty-four per cent of patients were impaired on two or more of the tests, suggesting a significant degree of measurable cognitive dysfunction. The number of patients who had not received PCI was insufficient for comparative analysis with the number who had, but among those treated with PCI, patients receiving 8 Gy in 1 fraction appeared less impaired than those receiving higher radiation doses in multiple fractions. The study showed that neuropsychometric testing is acceptable to patients, can be administered by non-psychologists in the clinic and is sensitive to otherwise undetected deficits of cognitive function in this patient population. Prospective evaluation of PCI should include neuropsychometric testing.

Hepatitis A vaccine administration: comparison between jet-injector and needle injection

INTRODUCTION

Type A hepatitis virus (HAV) is a serious health problem throughout the world and can be spread via fecal-oral contact. Both immune globulin and an HAV vaccine provide protection, but the vaccine gives complete protection. Efficacy of methods of vaccination in relation to the formation of anti-HAV antibodies is unclear; thus, this study seeks to determine if significant differences exist between the syringe as compared to the jet injection technique. The purpose of this study was to compare in a randomized trial Biojet jet-injection system to a needle-syringe method. To determine if a significant difference between these two methods in seroconversion rates or geometric mean titers of anti HAV antibody occurs at day 15, 30, and 210 days after vaccination.

METHOD

Anti-HAV IgG(-) adult hospital employees were randomized to receive 1440 EL.U of hepatitis a vaccine (HAVRIX(R)) in 2 doses by either needle or jet-injector (Biojector(R)) system at month 0 and 6. HAV seroconversion titer results were measured by the Boehringer-Mannheim method.

RESULTS/DISCUSSION

A higher proportion of persons who received HAV vaccine via the Biojector(R) seroconverted with anti-HAV level >/=20 mIU at day 15, 30, and month 7 when compared with a needle injection.Side-effect profiles reported by participants in both methods were below those identified in current published and insert information, but the Biojector(R) had greater local reactivity in all categories when compared to the needle method.

Intraluminal irradiation for the palliation of lung cancer with the high dose rate micro-Selectron

Fifty patients with inoperable, symptomatic endobronchial carcinoma were treated by a single exposure of intraluminal radiotherapy. A high dose rate afterloading system (the micro-Selectron-HDR) was used to minimise radiation exposure for staff. Haemoptysis was relieved in 24 of 28 patients, breathlessness in 21 of 33 patients, and cough in nine of 18 patients. Radiological collapse resolved in 11 of 24 patients. Treatment was given on an outpatient basis and was well tolerated. Intraluminal radiotherapy appears to offer an effective alternative to conventional fractionated external beam radiotherapy.

High dose rate intraluminal radiotherapy for carcinoma of the bronchus: outcome of treatment of 406 patients

In April 1988 the Christie Hospital started using the microSelectron-HDR machine to deliver intraluminal radiotherapy (ILT) to inoperable bronchial carcinomas causing symptoms due to endobronchial disease. Results of treatment in the first 406 patients with primary non-small-cell carcinoma are presented. Three main categories of patient were defined. Category 1 consisted of 324 patients (79.8%) who were previously unirradiated and received a single fraction of ILT as their primary treatment, mostly to a dose of 1500 cGy (76%) or 2000 cGy (23%) at 1 cm from the centre of the iridium-192 treatment source. The percentage of these patients whose symptoms or signs were improved at 6 weeks following ILT were as follows: stridor 92%, haemoptysis 88%, cough 62%, dyspnoea, 60%, pain, 50% and pulmonary collapse, 46%. Approximately two-thirds of these patients (67.3%) derived long lasting palliation and required no further treatment during their lifetime. The other third of patients needed subsequent treatment at some stage because of recurrence of their symptoms and in this situation external beam radiotherapy (EB) or a repeat ILT treatment was effectively utilised. Category 2 consisted of 65 patients (16%) who had previously received EB but required ILT when their tumour recurred. At 6 weeks post-ILT levels of symptom palliation were broadly similar to those obtained if ILT was used in previously unirradiated individuals, although the improvement was not so well sustained with time and only 7% showed improvement in pulmonary collapse at 6 weeks. Category 3 consisted of 17 patients (4.2%) in whom ILT was used concurrently with EB as a combined initial treatment. Similar levels of palliation were seen when compared with patients who received a single ILT treatment only. Overall, ILT was well tolerated in terms of early and late morbidity. In conclusion, the efficiency of a single ILT treatment in palliating symptoms due to endobronchial tumour in previously unirradiated individuals is comparable with that reported in series where treatment for advanced lung cancer combines a prolonged course of EB concurrently with several ILT treatments.

Massive haemoptysis death and other morbidity associated with high dose rate intraluminal radiotherapy for carcinoma of the bronchus

Four hundred and six patients with primary non-small cell carcinoma of the bronchus causing symptoms due to endobronchial disease, were treated with intraluminal radiotherapy (ILT) using the microSelectron-HDR machine at the Christie Hospital, Manchester, between April 1988 and the end of 1992. An assessment of morbidity for this treatment is presented, particularly with regard to the risk factors and causes of massive haemoptysis death. The most common early side-effect was a mild transient exacerbation of cough which usually resolved within 2-3 weeks. At various times following ILT treatment 83 bronchoscopies were carried out randomly in 55 patients. In bronchoscopies carried out within the first 3 months following ILT, no tumour was visible in 80% of cases. A mucosal radiation reaction score (RRS) was used to grade bronchoscopic appearance after ILT treatment. Overall, 55% of bronchoscopic examinations showed some degree of mucosal radiation reaction. The majority of radiation reactions from 6 months onwards after ILT demonstrated a degree of fibrosis. A radiation reaction was seen more frequently after treatment with 2000 cGy as opposed to 1500 cGy at 1 cm from the central axis of the radiation source. Thirty-two patients were identified who had died from massive haemoptysis (MH) as a terminal event. A Cox multivariate regression analysis showed that the treatment-related factors of increased dose at first ILT (P = 0.004), prior laser treatment at the site of ILT (P = 0.020) and second ILT treatment in the same location as the first ILT treatment (P = 0.047), all significantly increased the relative risk of MH death compared with their effect on the relative risk of death from other causes (OC). (In addition a fourth treatment-related factor, namely the concurrent use of ILT and external beam radiotherapy (EB) had a P value of 0.08). Twenty out of 25 assessable MH-death patients (80%) had evidence of recurrent or residual tumour before death but 5 patients (20%) did not. For surviving patients the instantancious risk of death at any one time (the cause-specific death rate expressed as deaths per 100 cases per month), showed a sharp peak for MH deaths between 9 and 12 months post ILT in contradistinction to OC death where the peak was between 3 and 6 months post ILT. These findings may imply a role for late radiation reaction in the treatment-related risk factors identified as increasing the relative risk of MH death and possible mechanisms are discussed. The results have implications for treatment regimes that use a dose of 2000 cGy at 1 cm in a single fraction technique, that have a high frequency of previous laser treatment, that use multiple, repeated ILT treatments in the same location and that use ILT concurrently with EB.

Cost effectiveness of alcoholism treatment in partial vs inpatient settings. Six-month outcomes

Six-month outcomes for alcohol misusers assigned to extended inpatient hospitalization and to partial hospitalization were comparable for alcohol consumption and social and vocational roles. However, the subjective well-being of partial hospital patients was greater and their treatment costs were lower.

Gap junctions and Bystander Effects: Good Samaritans and executioners

The "Bystander" and "Good Samaritan" effects involve the transfer of toxic or beneficial compounds from one cell to a generally adjacent other through gap junction channels and through extracellular routes. The variety of injuries in which bystander cell killing or protection occurs has greatly expanded in the last decade to include infectious agents and therapeutic compounds, radiation injury, chaperones in cell therapy and apoptosis in development. This has been accompanied by the appreciation that both gap junction mediated and paracrine routes are used for the signaling of the "kiss of life" and the "kiss of death" and that manipulations of these pathways and the molecules that use them may find therapeutic utility in treatment of a variety of pathological conditions.

Nanopore sensing of botulinum toxin type B by discriminating an enzymatically cleaved Peptide from a synaptic protein synaptobrevin 2 derivative

Botulinum neurotoxins (BoNTs) are the most lethal toxin known to human. Biodefense requires early and rapid detection of BoNTs. Traditionally, BoNTs can be detected by looking for signs of botulism in mice that receive an injection of human material, serum or stool. While the living animal assay remains the most sensitive approach, it is costly, slow and associated with legal and ethical constrains. Various biochemical, optical and mechanical methods have been developed for BoNTs detection with improved speed, but with lesser sensitivity. Here, we report a novel nanopore-based BoNT type B (BoNT-B) sensor that monitors the toxin's enzymatic activity on its substrate, a recombinant synaptic protein synaptobrevin 2 derivative. By analyzing the modulation of the pore current caused by the specific BoNT-B-digested peptide as a marker, the presence of BoNT-B at a subnanomolar concentration was identified within minutes. The nanopore detector would fill the niche for a much needed rapid and highly sensitive detection of neurotoxins, and provide an excellent system to explore biophysical mechanisms for biopolymer transportation.

Comparative analysis of optogenetic actuators in cultured astrocytes

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We compared six optogenetic tools to selectively stimulate and study astrocytes.

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Channelrhodopsin-2 variants cause release of Ca²⁺ from intracellular stores.

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Opto-GPCRs activate selective second messenger cascades, leading to [Ca²⁺]_i rises.

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Autocrine action of ATP mediates the bulk of [Ca²⁺]_i signals evoked by opto-GPCRs.

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Current optogenetic tools initiate relevant signalling events in astrocytes.

Astrocytes modulate synaptic transmission via release of gliotransmitters such as ATP, glutamate, d-serine and l-lactate. One of the main problems when studying the role of astrocytes in vitro and in vivo is the lack of suitable tools for their selective activation. Optogenetic actuators can be used to manipulate astrocytic activity by expression of variants of channelrhodopsin-2 (ChR2) or other optogenetic actuators with the aim to initiate intracellular events such as intracellular Ca²⁺ ([Ca²⁺]_i) and/or cAMP increases. We have developed an array of adenoviral vectors (AVV) with ChR2-like actuators, including an enhanced ChR2 mutant (H134R), and a mutant with improved Ca²⁺ permeability (Ca²⁺ translocating channelrhodopsin, CatCh). We show here that [Ca²⁺]_i elevations evoked by ChR2(H134R) and CatCh in astrocytes are largely due to release of Ca²⁺ from the intracellular stores. The autocrine action of ATP which is released under these conditions and acts on the P2Y receptors also contributes to the [Ca²⁺]_i elevations. We also studied effects evoked using light-sensitive G-protein coupled receptors (opto-adrenoceptors). Activation of optoα1AR (Gq-coupled) and optoβ2AR (G_s-coupled) resulted in astrocytic [Ca²⁺]_i increases which were suppressed by blocking the corresponding intracellular signalling cascade (phospholipase C and adenylate cyclase, respectively). Interestingly, the bulk of [Ca²⁺]_i responses evoked using either optoAR was blocked by an ATP degrading enzyme, apyrase, or a P2Y1 receptor blocker, MRS 2179, indicating that they are to a large extent triggered by the autocrine action of ATP. We conclude that, whilst optimal tools for control of astrocytes are yet to be generated, the currently available optogenetic actuators successfully initiate biologically relevant signalling events in astrocytes.

Nitric oxide production: a mechanism of Chlamydia trachomatis inhibition in interferon-gamma-treated RAW264.7 cells

IFN-gamma and/or LPS induced nitrite production and inhibition of Chlamydia trachomatis (CT) replication in the murine macrophage cell line, RAW264.7. Linear regression analysis demonstrated a strong correlation between nitrite production and inhibition of CT replication (correlation coefficients: -0.93, P < 0.001). L-NMMA specifically inhibited nitrite production and restored CT replication (55-71%). Inducible nitric oxide synthase (iNOS) mRNA was analyzed by Northern and dot blot hybridization with an iNOS cDNA probe. A strong correlation between iNOS mRNA expression and inhibition of CT replication also was observed (correlation coefficient: -0.97, P < 0.05). Furthermore, anti-TNF-alpha antibody, which completely neutralized biological activity of the secreted TNF-alpha, neither inhibited nitrite production nor restored CT replication in the LPS- and/or IFN-gamma-treated RAW264.7 cells. In mouse peritoneal macrophages treated with IFN-gamma, both L-NMMA and anti-TNF-alpha antibody inhibited nitrite production and restored CT replication. However, L-NMMA and the antibody had no effect upon nitrite production and CT inhibition in LPS-treated peritoneal macrophages. These data indicate that NO production is one mechanism for inhibition of CT replication in IFN-gamma-activated murine macrophages.

Matching treatment focus to patient social investment and support: 18-month follow-up results

Patients were randomly assigned to 1 of 3 treatments: brief broad-spectrum (BBS), extended relationship enhancement (ERE), or extended cognitive-behavioral (ECB). A hierarchical latent growth model was used to analyze the data of 188 patients (82%) followed for 18 months. ERE treatment was significantly more effective in increasing abstinence of patients entering treatment with a network unsupportive of abstinence or with a low level of investment in their network, whereas BBS treatment was more effective for patients with either (a) both a social network unsupportive of abstinence and a low level of network investment or (b) high investment in a network supportive of abstinence. ECB outcomes were neither as good as those matched nor as bad as those mismatched to the different exposures of relationship enhancement. This suggests that dose of relationship enhancement should be determined after assessing patient relationships.

Multifunctional cytokine expression by human mast cells: regulation by T cell membrane contact and glucocorticoids

Human mast cells readily release a variety of mediators, including cytokines, in response to IgE receptor crosslinking, but the mechanisms governing the expression of cytokines are still unclear. Using a human mast cell line, HMC-1, we show expression of cytokine transcripts as early as 2 h after activation with ionomycin and phorbol myristate acetate (PMA). Resting HMC-1 cells expressed transcripts for interleukin-1 receptor antagonist (IL-1RA), IL-2, IL-4, IL-5, GM-CSF, and weakly for IL-8, and stimulation with ionomycin and PMA induced additional transcripts for IL-6 and IL-13 and upregulated expression of IL-8 transcripts. HMC-1 cells secreted IL-4, IL-8, and GM-CSF protein after activation and dexamethasone significantly inhibited the production of these cytokines. Of significance is the finding that the addition of membranes purified from activated T cells to mast cell cultures induced transcripts selectively for IL-8 and none for other proinflammatory cytokines. Flow cytometry revealed that resting HMC-1 cells express CD40, a molecule involved in contact-dependent signaling of monocytes and B cells by T cells. However, activation of HMC-1 by anti-CD40 antibody did not induce IL-8 gene expression or protein production. This study demonstrates that human mast cells are capable of expressing multiple cytokines that can be inhibited by glucocorticoids. It also raises the possibility that T cells may activate mast cell cytokine synthesis by novel contact-dependent mechanisms. This phenomenon of T cell regulation of mast cell function requires further study.