Automated gesture tracking in head-fixed mice

BACKGROUND

The preparation consisting of a head-fixed mouse on a spherical or cylindrical treadmill offers unique advantages in a variety of experimental contexts. Head fixation provides the mechanical stability necessary for optical and electrophysiological recordings and stimulation. Additionally, it can be combined with virtual environments such as T-mazes, enabling these types of recording during diverse behaviors.

NEW METHOD

In this paper we present a low-cost, easy-to-build acquisition system, along with scalable computational methods to quantitatively measure behavior (locomotion and paws, whiskers, and tail motion patterns) in head-fixed mice locomoting on cylindrical or spherical treadmills.

EXISTING METHODS

Several custom supervised and unsupervised methods have been developed for measuring behavior in mice. However, to date there is no low-cost, turn-key, general-purpose, and scalable system for acquiring and quantifying behavior in mice.

RESULTS

We benchmark our algorithms against ground truth data generated either by manual labeling or by simpler methods of feature extraction. We demonstrate that our algorithms achieve good performance, both in supervised and unsupervised settings.

CONCLUSIONS

We present a low-cost suite of tools for behavioral quantification, which serve as valuable complements to recording and stimulation technologies being developed for the head-fixed mouse preparation.

Whistle Abrasion: A Case Report

Abrasion is the physical wearing of a tooth surface which can involve the presence of a foreign object repeatedly being in contact with the tooth. A 40-year-old male patient reported to our dental clinic with a 2–3 mm uneven gap between his upper and lower front teeth on occlusion. A detailed history revealed that he was a physical education teacher, and the habitual placement of the whistle for the last 15 years caused an indentation on the whistle which coincided with the abraded teeth. Conditions such as abrasion may need active restorations. A general dental practitioner should accurately identify the cause and treat the esthetic and functional impairment as required.

Assessing suicide risk with the Clinical Interview for Psychotic Disorders (CIPD): Preliminary reliability and validity of the Suicide Risk Scale for Psychosis (SRS-P)

Background

Suicide risk is an important variable to consider both in assessment and throughout the therapeutic process in psychotic disorders. The SRS-P is an 18-item scale computed from the patient and clinician-rated scores obtained in the CIPD. The scale comprises lifetime assessment of depressed mood, anhedonia and its current interference and severity, current and past feelings of hopelessness, suicidal ideation, ‘voices’ about suicide, and suicide-related behaviors.

Aims

To assess reliability and convergent validity of the SRS-P in a sample of participants with psychosis.

Methods

The sample comprised 22 participants (68.2% male), single (72.7%), between 19 and 47 years old (M = 31.05; SD = 7.088), with 4–17 years of education (M = 11.77; SD = 3.176), employed (50%). The most prevalent diagnosis was schizophrenia (68.2%) and the participants had a mean of 1.90 hospitalizations (SD = 2.548). The mean age of illness onset was 23.57 years (SD = 5.555). The participants were assessed with the CIPD, Depression, Anxiety and Stress Scales-21, Forms of Self-Criticism and Reassurance Scale, Self-Compassion Scale, Other as Shamer Scale and the Empowerment with Psychotic Symptoms Scales.

Results

The SRS-P has shown good reliability (α = .87) and validity in relation to depressive symptoms (r = .67; P = .001), anxiety (r = .74; P < .001), stress (r = .59; P = .004), inadequate self (r = .43; P = .046), hated self (r = .54; P = .009), reassured self (r = –.65; P = .001), self-compassion (r = –.63; P = .002), shame (r = .46; P = .033) and empowerment regarding positive symptoms (r = –.54; P = .015).

Conclusions

The SRS-P presented adequate reliability and convergent-divergent validity. Further studies are planned in order to test the factorial structure of the scale and confirm the presented results in a larger sample.

Disclosure of interest

The authors have not supplied their declaration of competing interest.

A psychiatric liaison team at the university medical services: A pilot experience

Introduction

University students represent a specific population with concerns, burdens and worries that differ from other age and occupation groups. Students’ experiences are often exciting and empowering, yet facing multiple stressors that may trigger various forms of psychopathology. Our psychiatry department created a specific liaison service for university students in order to provide an easy and quick access to this medical speciality, included at the Multidisciplinary University Medical Services.

Aims

To characterize a sample of college student users of our Psychiatry Liaison Unit regarding socio-demographic and clinic variables.

Methods

Socio-demographic and clinic characterization was undertaken in all students observed during sixteen months (1st April 2015–30th July 2016).

Results

Fifty-three outpatients were observed: 35 females (66%) and 18 males (34%), aged between 18 and 39 years old (average: 23.94; median: 23). The majority was Portuguese and lived originally in urban areas. A total of75.3% were displaced and 60% lived with colleagues while 84.9% attended an undergraduate degree, and 38% studied at faculty of Science and Technology. Clinically, 79.2% were referenced by the University Medical Services, and adjustment disorders (ICD-10 F43.2) were the most frequent diagnosis. Relatively to suicidal behaviors and self-harm, 5.7% did self-cutting, 49.1% took an antidepressant combined with another psychotropic drugs, and 81.1% maintained cognitive-behavioral interventions.

Conclusions

The typical university students’ psychiatry outpatient was of female gender, in an undergraduate degree, displaced and living without their family. The most frequent diagnosis was adjustment disorder, and about a quarter were successfully discharged. Multidisciplinary University Medical Services located near to students can easily refer patients to Psychiatry Liaison Units, allowing diagnosis and intervention at early stages of mental disease.

Disclosure of interest

The authors have not supplied their declaration of competing interest.

Preparation and characterization of electrical conductive PVA based materials for peripheral nerve tube-guides

Peripheral nerve regeneration is a serious clinical problem. Presently, there are several nerve tube-guides available in the market, however with some limitations. The goal of this work was the development of a biomaterial with high electrical conductivity to produce tube-guides for nerve regeneration after neurotmesis injuries whenrver an end-to-end suture without tension is not possible. A matrix of poly(vinyl alcohol) (PVA) was used loaded with the following electrical conductive materials: COOH-functionalized multiwall carbon nanotubes (MWCNTs), poly(pyrrole) (PPy), magnesium chloride (MgCl2 ), and silver nitrate (AgNO3 ). The tube-guide production was carried out by a freezing/thawing process (physical crosslinking) with a final annealing treatment. After producing the tube-guide for nerve regeneration, the physicochemical characterization was performed. The most interesting results were achieved by loading PVA with 0.05% of PPy or COOH- functionalized CNTs. These tubes combined the electrical conductivity of carbon nanotubes (CNTs) and PPy with the biocompatibility of PVA matrix, with potential clinical application for nerve regeneration. © 2016 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 104A: 1981-1987, 2016.

Quantitative Evaluation of Macrophage Expression Using CD68 in Oral Submucous Fibrosis: An Immunohistochemical Study

BACKGROUND

Macrophages are important cells for the innate immunity. Circulating monocytes are attracted to tissues by chemotactic factors and become macrophages under the influence of their microenvironment. Several studies suggested that local and systemic upregulation of fibrogenic cytokines and downregulation of antifibrotic cytokine are central to the pathogenesis of oral submucous fibrosis (OSMF). Currently, there have been no attempts made to elucidate the presence and role of macrophages in OSMF.

AIM

Our aim was to study the expression of CD68 in OSMF patients and to investigate the possible correlation of macrophages using CD68 in various histopathological grades of OSMF.

SUBJECTS AND METHODS

A prospective case-control study which included 40 patients was conducted after obtaining informed consent and Ethical Committee clearance. Ten cases were normal control and thirty cases had OSMF. Biopsy was performed and a quantitative study of macrophages was done using CD68 antigen and was immunohistochemically localized. Statistical analysis was carried out using the Statistical Package for Social Sciences (SPSS) 17.0 version (SPSS Inc., Chicago, IL, USA).

RESULTS

OSMF was observed in male patients of a younger age group. The macrophage number in the patients of intermediate and advanced stage of OSMF was higher than that of the controls which was statistically significant (P < 0.05).

CONCLUSION

The findings of this study suggest that CD68 plays a vital role in the pathogenesis of OSMF and can be regarded as a useful marker for assessing the progress of the disease.

A new sheep model with automatized analysis of biomaterial-induced bone tissue regeneration

Presently, several bone graft substitutes are being developed or already available for clinical use. However, the limited number of clinical and in vivo trials for direct comparison between these products may complicate this choice. One of the main reasons for this scarcity it is the use of models that do not readily allow the direct comparison of multiple bone graft substitutes, due especially to the small number of implantation sites. Although sheep cancellous bone models are now well established for these purposes, the limited availability of cancellous bone makes it difficult to find multiple comparable sites within a same animal. These limitations can be overcome by the monocortical model here proposed as it consists in 5-6 holes (5 mm Ø), in the femoral diaphysis, with similar bone structure, overlying soft tissue and loading pattern for all defects. Associated to this model, it is also described a fast histomorphometric analysis method using a computer image segmentation test (Threshold method) to assess bone regeneration parameters. The information compiled through the experimental use of 45 sheep in several studies allowed determining that this ovine model has the potential to demonstrate differences in bone-forming performance between various scaffolds. Additionally, the described histomorphometric method is fast, accurate and reproducible.

Central arterial hemodynamic effects of dark chocolate ingestion in young healthy people: a randomized and controlled trial

Introduction. The aim of this study was to assess the vascular benefits of dark chocolate in healthy and young individuals. Methods. A randomized and controlled trial was carried out involving 60 healthy volunteers, randomized into two groups: control group (CG; n = 30) and intervention group (IG; n = 30). The IG ingested a daily dosage of 10 g of dark chocolate (>75% cocoa) for a month. Blood pressure (BP), flow-mediated dilation (FMD), arterial stiffness index (ASI), aortic pulse wave velocity (PWV), and pulse wave analysis (PWA) were assessed at baseline and one week after the one-month intervention period. Results. Arterial function improved after intervention in the IG, with PWV decreasing from 6.13 ± 0.41 m/s to 5.83 ± 0.53 m/s (P = 0.02), with no significant differences observed in the CG. A significant decrease in ASI (0.16 ± 0.01 to 0.13 ± 0.01; P < 0.001) and AiX (-15.88 ± 10.75 to -22.57 ± 11.16; P = 0.07) was also depicted for the IG. Endothelial function improved in the IG, with the FMD increasing 9.31% after the 1-month intervention (P < 0.001), with no significant variation in the CG. Conclusion. The daily ingestion of 10 g dark chocolate (>75% cocoa) during a month significantly improves vascular function in young and healthy individuals.

Effects of umbilical cord tissue mesenchymal stem cells (UCX®) on rat sciatic nerve regeneration after neurotmesis injuries

Peripheral nerves have the intrinsic capacity of self-regeneration after traumatic injury but the extent of the regeneration is often very poor. Increasing evidence demonstrates that mesenchymal stem/stromal cells (MSCs) may play an important role in tissue regeneration through the secretion of soluble trophic factors that enhance and assist in repair by paracrine activation of surrounding cells. In the present study, the therapeutic value of a population of umbilical cord tissue-derived MSCs, obtained by a proprietary method (UCX^®), was evaluated on end-to-end rat sciatic nerve repair. Furthermore, in order to promote both, end-to-end nerve fiber contacts and MSC cell-cell interaction, as well as reduce the flush away effect of the cells after administration, a commercially available haemostatic sealant, Floseal^®, was used as vehicle. Both, functional and morphologic recoveries were evaluated along the healing period using extensor postural thrust (EPT), withdrawal reflex latency (WRL), ankle kinematics analysis, and either histological analysis or stereology, in the hyper-acute, acute and chronic phases of healing. The histological analysis of the hyper-acute and acute phase studies revealed that in the group treated with UCX^® alone the Wallerian degeneration was improved for the subsequent process of regeneration, the fiber organization was higher, and the extent of fibrosis was lower. The chronic phase experimental groups revealed that treatment with UCX^® induced an increased number of regenerated fibers and thickening of the myelin sheet. Kinematics analysis showed that the ankle joint angle determined for untreated animals was significantly different from any of the treated groups at the instant of initial contact (IC). At opposite toe off (OT) and heel rise (HR), differences were found between untreated animals and the groups treated with either uCx^® alone or UCX^® administered with Floseal^®. Overall, the UCX^® application presented positive effects in functional and morphologic recovery, in both the acute and chronic phases of the regeneration process. Kinematics analysis has revealed positive synergistic effects brought by Floseal^® as vehicle for MSCs.

Bacterial cellulose membranes as drug delivery systems: an in vivo skin compatibility study

Bacterial cellulose (BC) is a highly pure form of cellulose, produced in the form of a swollen membrane by several bacteria that demonstrated to be able to modulate the skin release of model drugs. In the present study, the skin irritation potential of BC was evaluated in human subjects. BC membranes with and without glycerin (acting as plasticizer) were tested. No significant differences were observed for transepidermal water loss (TEWL) measurements in comparison with negative control, 2 and 24 h after patch removal, which is an indicator of an absence of barrier disruption. Similar results were found for erythema. Clinical scores were zero at both times for all volunteers, with the exception of five volunteers that exhibited weak reactions. BC with glycerin provided a skin moisturizing effect statistically higher than the negative control (p=0.044), which was not observed for BC alone. The good skin tolerance found after a single application under occlusion reinforces the putative interest of BC membranes as supports for drug topical delivery. Besides modifying the mechanical properties, the inclusion of glycerin results in a skin moisturizing effect which could be clinically relevant for the treatment for skin diseases characterized by dryness, such as psoriasis and atopic dermatitis.

Use of poly(DL-lactide-ε-caprolactone) membranes and mesenchymal stem cells from the Wharton's jelly of the umbilical cord for promoting nerve regeneration in axonotmesis: in vitro and in vivo analysis

Cellular systems implanted into an injured nerve may produce growth factors or extracellular matrix molecules, modulate the inflammatory process and eventually improve nerve regeneration. In the present study, we evaluated the therapeutic value of human umbilical cord matrix MSCs (HMSCs) on rat sciatic nerve after axonotmesis injury associated to Vivosorb® membrane. During HMSCs expansion and differentiation in neuroglial-like cells, the culture medium was collected at 48, 72 and 96 h for nuclear magnetic resonance (NMR) analysis in order to evaluate the metabolic profile. To correlate the HMSCs ability to differentiate and survival capacity in the presence of the Vivosorb® membrane, the [Ca(2+)]i of undifferentiated HMSCs or neuroglial-differentiated HMSCs was determined by the epifluorescence technique using the Fura-2AM probe. The Vivosorb® membrane proved to be adequate and used as scaffold associated with undifferentiated HMSCs or neuroglial-differentiated HMSCs. In vivo testing was carried out in adult rats where a sciatic nerve axonotmesis injury was treated with undifferentiated HMSCs or neuroglial differentiated HMSCs with or without the Vivosorb® membrane. Motor and sensory functional recovery was evaluated throughout a healing period of 12 weeks using sciatic functional index (SFI), extensor postural thrust (EPT), and withdrawal reflex latency (WRL). Stereological analysis was carried out on regenerated nerve fibers. In vitro investigation showed the formation of typical neuroglial cells after differentiation, which were positively stained for the typical specific neuroglial markers such as the GFAP, the GAP-43 and NeuN. NMR showed clear evidence that HMSCs expansion is glycolysis-dependent but their differentiation requires the switch of the metabolic profile to oxidative metabolism. In vivo studies showed enhanced recovery of motor and sensory function in animals treated with transplanted undifferentiated and differentiated HMSCs that was accompanied by an increase in myelin sheath. Taken together, HMSC from the umbilical cord Wharton jelly might be useful for improving the clinical outcome after peripheral nerve lesion.

A child with BK virus infection: inadequacy of current therapeutic strategies

In this report, we describe the development of BKVN in the native kidneys of a child with a cardiac transplant. Elevated BK viral DNA load by PCR necessitated a prolonged course of treatment with escalating doses of cidofovir. Despite a reduction in plasma BK viral load, the infection evolved into an invasive CNS disease, resulting in rhomboencephalitis. This case highlights the need for awareness of the possibility of developing multiorgan complications from BKV infection. The current treatment options for BKV tissue invasive disease are inadequate and need to be improved.

Temperature increase at the light guide tip of 15 contemporary LED units and thermal variation at the pulpal floor of cavities: an infrared thermographic analysis

In this study, a comprehensive investigation on the temperature increase at the light guide tip of several commercial light-emitting diode (LED) light-curing units (LCUs) and the associated thermal variation (ΔT) at the pulpal floor of dental cavities was carried out. In total, 15 LEDs from all generations were investigated, testing a quartz-tungsten-halogen (QTH) unit as a reference. The irradiance level was measured with a power meter, and spectral distribution was analyzed using a spectrometer. Temperature increase at the tip was measured with a type-K thermocouple connected to a thermometer, while ΔT at the pulpal floor was measured by an infrared photodetector in class V cavities, with a 1-mm-thick dentin pulpal floor. The relationship among measured irradiance, ΔT at the tip, and ΔT at the pulpal floor was investigated using regression analyses. Large discrepancies between the expected and measured irradiances were detected for some LCUs. Most of the LCUs showed an emission spectrum narrower than the QTH unit, with emission peaks usually between 450 and 470 nm. The temperature increase at the tip followed a logarithmic growth for LCUs with irradiance ≥1000 mW/cm(2), with ΔT at the tip following the measured irradiance linearly (R(2)=0.67). Linear temperature increase at the pulpal floor over the 40-second exposure time was observed for several LCUs, with linear association between ΔT at the pulpal floor and measured irradiance (R(2)=0.39) or ΔT at the tip (R(2)=0.28). In conclusion, contemporary LED units show varied irradiance levels that affect the temperature increase at the light guide tip and, as a consequence, the thermal variation at the pulpal floor of dental cavities.

Phase synchronization of bursting neurons in clustered small-world networks

We investigate the collective dynamics of bursting neurons on clustered networks. The clustered network model is composed of subnetworks, each of them presenting the so-called small-world property. This model can also be regarded as a network of networks. In each subnetwork a neuron is connected to other ones with regular as well as random connections, the latter with a given intracluster probability. Moreover, in a given subnetwork each neuron has an intercluster probability to be connected to the other subnetworks. The local neuron dynamics has two time scales (fast and slow) and is modeled by a two-dimensional map. In such small-world network the neuron parameters are chosen to be slightly different such that, if the coupling strength is large enough, there may be synchronization of the bursting (slow) activity. We give bounds for the critical coupling strength to obtain global burst synchronization in terms of the network structure, that is, the probabilities of intracluster and intercluster connections. We find that, as the heterogeneity in the network is reduced, the network global synchronizability is improved. We show that the transitions to global synchrony may be abrupt or smooth depending on the intercluster probability.

[Percutaneous Image-guided cryoablation for localized bone plasmacytoma treatment]

Bone plasmacytoma (BP) occurs in most patients with multiple myeloma and is highly disabling. Radiotherapy is the primary treatment modality for BP and, although local control rates are excellent, several weeks are needed before the treatment is completed and for patients to note significant pain relief. Over the past decade, percutaneous image-guided cryoablation has emerged as a safe and effective alternative in the management of localized bone metastasis in solid tumours. In this report the author's show that a localized BP was successfully treated using this procedure. Furthermore, some of the most relevant potential advantages that makes this procedure more attractive than other alternative techniques are highlighted.

Primary cutaneous actinomycosis caused by Actinomyces meyeri as first manifestation of HIV infection

Primary cutaneous actinomycosis is very uncommon. We report a patient with cutaneous actinomycosis with multiple lesions without any detectable extra-cutaneous lesions. In our patient the actinomycosis was the presenting manifestation of HIV infection.

Three decades of progress in treating childhood-onset lupus nephritis

BACKGROUND AND OBJECTIVES

Childhood-onset lupus nephritis (LN) carries a worse renal prognosis compared with adults. Controlled treatment trials in children are lacking. We compared renal and patient survival in a cohort of pediatric patients followed over 3 decades.

DESIGN, SETTINGS, PARTICIPANTS, & MEASUREMENTS

A retrospective analysis was conducted on 138 patients with childhood-onset systemic lupus erythematosus from 1980 to 2010. The core cohort included 95 with severe LN: 28 progressed to end-stage renal disease (ESRD group) whereas 67 did not (no-ESRD group). Patients were stratified into four "eras" according to the introduction of the primary immuno-suppressive drug: era 1: triple oral therapy with corticosteroids (CS), cyclophosphamide (CYC), and azathioprine (AZA); era 2: intravenous CYC; era 3: mycophenolate mofetil (MMF) ± CYC; era 4: rituximab (RTX) ± CYC ± MMF.

RESULTS

Mean age at diagnosis was 12.3 ± 2.9 years with median follow-up of 5 years. Poor renal function (estimated GFR < 60 ml/min per 1.73 m(2)) and nephrotic proteinuria at diagnosis imparted a poor prognosis. Increasing proteinuria correlated with progression of kidney disease. The addition of MMF in era 3 improved 5-year renal survival from 52% to 91% and overall patient survival from 83% to 97%. African-American ethnicity was associated with significant risk for progression to ESRD whereas Hispanic ethnicity conferred an advantage. Infection and cardiovascular disease were the primary causes of patient demise.

CONCLUSIONS

Renal and patient survival in childhood-onset LN has improved during the past 3 decades with progressive treatment regimens. Future trials in children are very much warranted.

High glucose changes extracellular adenosine triphosphate levels in rat retinal cultures

Diabetic retinopathy (DR) is the leading cause of blindness in adults. In diabetes, there is activation of microglial cells and a concomitant release of inflammatory mediators. However, it remains unclear how diabetes triggers an inflammatory response in the retina. Activation of P2 purinergic receptors by adenosine triphosphate (ATP) may contribute to the inflammatory response in the retina, insofar as it has been shown to be associated with microglial activation and cytokine release. In this work, we evaluated how high glucose, used as a model of hyperglycemia, considered the main factor in the development of DR, affects the extracellular levels of ATP in retinal cell cultures. We found that basal extracellular ATP levels were not affected by high glucose or mannitol, but the extracellular elevation of ATP, after a depolarizing stimulus, was significantly higher in retinal cells cultured in high glucose compared with control or mannitol-treated cells. The increase in the extracellular ATP was prevented by application of botulinum neurotoxin A or by removal of extracellular calcium. In addition, degradation of exogenously added ATP was significantly lower in high-glucose-treated cells. It was also observed that, in retinal cells cultured under high-glucose conditions, the changes in the intracellular calcium concentrations were greater than those in control or mannitol-treated cells. In conclusion, in this work we have shown that high glucose alters the purinergic signaling system in the retina, by increasing the exocytotic release of ATP and decreasing its extracellular degradation. The resulting high levels of extracellular ATP may lead to inflammation involved in the pathogenesis of DR.

Acute and chronic alcohol dose: population differences in behavior and neurochemistry of zebrafish

The zebrafish has been in the forefront of developmental genetics for decades and has also been gaining attention in neurobehavioral genetics. It has been proposed to model alcohol-induced changes in human brain function and behavior. Here, adult zebrafish populations, AB and SF (short-fin wild type), were exposed to chronic treatment (several days in 0.00% or 0.50% alcohol v/v) and a subsequent acute treatment (1 h in 0.00%, 0.25%, 0.50% or 1.00% alcohol). Behavioral responses of zebrafish to computer-animated images, including a zebrafish shoal and a predator, were quantified using videotracking. Neurochemical changes in the dopaminergic and serotoninergic systems in the brain of the fish were measured using high-precision liquid chromatography with electrochemical detection. The results showed genetic differences in numerous aspects of alcohol-induced changes, including, for the first time, the behavioral effects of withdrawal from alcohol and neurochemical responses to alcohol. For example, withdrawal from alcohol abolished shoaling and increased dopamine and 3,4-dihydroxyphenylacetic acid in AB but not in SF fish. The findings show that, first, acute and chronic alcohol induced changes are quantifiable with automated behavioral paradigms; second, robust neurochemical changes are also detectable; and third, genetic factors influence both alcohol-induced behavioral and neurotransmitter level changes. Although the causal relationship underlying the alcohol-induced changes in behavior and neurochemistry is speculative at this point, the results suggest that zebrafish will be a useful tool for the analysis of the biological mechanisms of alcohol-induced functional changes in the adult brain.

Real-time digital heterodyne interferometer for high resolution plasma density measurements at ISTTOK

With the implementation of alternating discharges (ac) at the ISTTOK tokamak, the typical duration of the discharges increased from 35 to 250 ms. This time increase created the need for a real-time electron density measurement in order to control the plasma fueling. The diagnostic chosen for the real-time calculation was the microwave interferometer. The ISTTOK microwave interferometer is a heterodyne system with quadrature detection and a probing frequency of 100 GHz (lambda(0)=3 mm). In this paper, a low-cost approach for real-time diagnostic using a digital signal programmable intelligent computer embedded system is presented, which allows the measurement of the phase with a 1% fringe accuracy in less than 6 micros. The system increases its accuracy by digitally correcting the offsets of the input signals and making use of a judicious lookup table optimized to improve the nonlinear behavior of the transfer curve. The electron density is determined at a rate of 82 kHz (limited by the analog to digital converter), and the data are transmitted for each millisecond although this last parameter could be much lower (around 12 micros--each value calculated is transmitted). In the future, this same system is expected to control plasma actuators, such as the piezoelectric valve of the hydrogen injection system responsible for the plasma fueling.

The pharmacokinetics and disposition of MK-0524, a Prostaglandin D2receptor 1 antagonist, in rats, dogs and monkeys

MK-0524 is a potent, selective and orally active Prosglandin D(2) Receptor 1 (DP(1)) antagonist currently under clinical development for the treatment of niacin-induced flushing. Experiments to study the pharmacokinetics, metabolism and excretion of MK-0524 were conducted in rats, dogs and monkeys. MK-0524 displayed linear kinetics and rapid absorption following an oral dose. Following intravenous (i.v.) administration of MK-0524 to rats and dogs (1 and 5 mg/kg), the mean Cl(p) was approximately 2 and approximately 6 ml/min/kg, the T(1/2) was approximately 7 and approximately 13 h and the Vd(ss) was approximately 1 and approximately 5 L/kg, respectively. In monkeys dosed i.v. at 3 mg/kg, the corresponding values were 8 ml/min/kg, 3 h and 1 L/kg, respectively. Following oral dosing of MK-0524 to rats (5, 25 and 100 mg/kg), dogs (5 mg/kg) and monkeys (3 mg/kg), the absorption was rapid with the mean C(max) occurring between 1 and 4 h. Absolute oral bioavailability values in rats, dogs and monkeys were 50, 70 and 8%, respectively. The major circulating metabolite was the acyl glucuronide of MK-0524 (M2), with ratios of glucuronide to the parent aglycone being highest in the monkey followed by dog and rat. In bile duct-cannulated rats and dogs, MK-0524 was eliminated primarily via acyl glucuronidation followed by biliary excretion of the acyl glucuronide, M2, the major drug-related entity in bile.

Community structure and antibiotic production of Streptomyces nodosus bioreactors cultured in liquid environments

Immobilized bacteria are being assessed by industry for drug delivery, novel fermentation systems and the protection of organisms in harsh environments. Alginate bioreactors containing Streptomyces nodosus were examined for community structure, cell viability and amphotericin production under different growth conditions. When cell proliferation was encouraged, substrate hyphae were found inside the alginate matrix and within multicellular projections on the surface of the capsule. The periphery of these projections had erect and branched hyphae, morphologically identical to aerial hyphae. Antibiotic production from immobilized organisms was assessed using conditioned culture medium to eliminate the emergence of a free-dwelling population. These organisms sporulated with reduced antibiotic production compared with free-dwelling cultures. The commitment to sporulate was independent of a surface but dependent on community size and nutritional status. This is the first report of the sporulation of S. nodosus in liquid cultures and description of the multicellular community the organism adopts at a solid-liquid interface.