Low-Frequency Entrainment to Visual Motion Underlies Sign Language Comprehension

When people listen to speech, neural activity tracks the entropy fluctuation in the acoustic envelope of the signal. This signal-based entrainment has been shown to be the basis of speech parsing and comprehension. In this electroencephalography (EEG) study, we compute sign language users’ cortical tracking of changes in visual dynamics of the communicative signal in the time-direct videos of sign language, and their time-reversed counterparts, and assess the relative contribution of response frequencies between.2 and 12.4 Hz to comprehension using a machine learning approach to brain state classification. Lower frequencies of EEG response (.2–4 Hz) yield 100% classification accuracy, while information about cortical tracking of the visual envelope in higher frequencies is less informative. This suggests that signers rely on lower visual frequency data, such as envelope of visual signal, for sign language comprehension. In the context of real-time language processing, given the speed of comprehension responses, this suggests that fluent signers employ a predictive processing heuristic based on sign language knowledge.

High-Definition Zoom Mode, a High-Resolution X-Ray Microscope for Neurointerventional Treatment Procedures: A Blinded-Rater Clinical-Utility Study

BACKGROUND AND PURPOSE

Quality of visualization of treatment devices during critical stages of endovascular interventions, can directly impact their safety and efficacy. Our aim was to compare the visualization of neurointerventional procedures and treatment devices using a 194-μm pixel flat panel detector mode and a 76-μm pixel complementary metal oxide semiconductor detector mode (high definition) of a new-generation x-ray detector system using a blinded-rater study.

MATERIALS AND METHODS

Deployment of flow-diversion devices for the treatment of internal carotid artery aneurysms was performed under flat panel detector and high-definition-mode image guidance in a neurointerventional phantom simulating patient cranium and tissue attenuation, embedded with 3D-printed intracranial vascular models, each with an aneurysm in the ICA segment. Image-sequence pairs of device deployments for each detector mode, under similar exposure and FOV conditions, were evaluated by 2 blinded experienced neurointerventionalists who independently selected their preferred image on the basis of visualization of anatomic features, image noise, and treatment device. They rated their selection as either similar, better, much better, or substantially better than the other choice. Inter- and intrarater agreement was calculated and categorized as poor, moderate, and good.

RESULTS

Both raters demonstrating good inter- and intrarater agreement selected high-definition-mode images with a frequency of at least 95% each and, on average, rated the high-definition images as much better than flat panel detector images with a frequency of 73% from a total of 60 image pairs.

CONCLUSIONS

Due to their higher resolution, high-definition-mode images are sharper and visually preferred compared with the flat panel detector images. The improved imaging provided by the high-definition mode can potentially provide an advantage during neurointerventional procedures.

A Type 1 Diabetes Genetic Risk Score Predicts Progression of Islet Autoimmunity and Development of Type 1 Diabetes in Individuals at Risk

OBJECTIVE

We tested the ability of a type 1 diabetes (T1D) genetic risk score (GRS) to predict progression of islet autoimmunity and T1D in at-risk individuals.

RESEARCH DESIGN AND METHODS

We studied the 1,244 TrialNet Pathway to Prevention study participants (T1D patients' relatives without diabetes and with one or more positive autoantibodies) who were genotyped with Illumina ImmunoChip (median [range] age at initial autoantibody determination 11.1 years [1.2-51.8], 48% male, 80.5% non-Hispanic white, median follow-up 5.4 years). Of 291 participants with a single positive autoantibody at screening, 157 converted to multiple autoantibody positivity and 55 developed diabetes. Of 953 participants with multiple positive autoantibodies at screening, 419 developed diabetes. We calculated the T1D GRS from 30 T1D-associated single nucleotide polymorphisms. We used multivariable Cox regression models, time-dependent receiver operating characteristic curves, and area under the curve (AUC) measures to evaluate prognostic utility of T1D GRS, age, sex, Diabetes Prevention Trial-Type 1 (DPT-1) Risk Score, positive autoantibody number or type, HLA DR3/DR4-DQ8 status, and race/ethnicity. We used recursive partitioning analyses to identify cut points in continuous variables.

RESULTS

Higher T1D GRS significantly increased the rate of progression to T1D adjusting for DPT-1 Risk Score, age, number of positive autoantibodies, sex, and ethnicity (hazard ratio [HR] 1.29 for a 0.05 increase, 95% CI 1.06-1.6; P = 0.011). Progression to T1D was best predicted by a combined model with GRS, number of positive autoantibodies, DPT-1 Risk Score, and age (7-year time-integrated AUC = 0.79, 5-year AUC = 0.73). Higher GRS was significantly associated with increased progression rate from single to multiple positive autoantibodies after adjusting for age, autoantibody type, ethnicity, and sex (HR 2.27 for GRS >0.295, 95% CI 1.47-3.51; P = 0.0002).

CONCLUSIONS

The T1D GRS independently predicts progression to T1D and improves prediction along T1D stages in autoantibody-positive relatives.

Initial investigations of a special high-definition (Hi-Def) zoom capability in a new detector system for neuro-interventional procedures

Real-time visualization of fine details ranging to 100 um or less in neuro-vascular imaging guided interventions is important. A separate high-resolution detector mounted on a standard flat panel detector (FPD) was previously reported. This device had to be rotated mechanically into position over the FPD for high resolution imaging. Now, the new detector reported here has a high definition (Hi-Def) zoom capability along with the FPD built into one unified housing. The new detector enables rapid switching, by the operator between Hi-Def and FPD modes. Standard physical metrics comparing the new Hi-Def modes with those of the FPD are reported, demonstrating improved imaging resolution and noise capability at patient doses similar to those used for the FPD. Semi-quantitative subjective studies involving qualitative clinician feedback on images of interventional devices such as a Pipeline Embolization Device (PED) acquired in both Hi-Def and FPD modes are presented. The PED is deployed in a patient specific 3D printed neuro-vascular phantom embedded inside realistic bone and with tissue attenuating material. Field-of-view (FOV), exposure and magnification were kept constant for FPD and Hi-Def modes. Static image comparisons of the same view of the PED within the phantom were rated by expert interventionalists who chose from the following ratings: Similar, Better, or Superior. Generally, the Hi-Def zoomed images were much preferred over the FPD, indicating the potential to improve endovascular procedures and hence outcomes using such a Hi-Def feature.

Spectroscopy with a CdTe-based photon-counting imaging detector (PCD) having charge sharing correction capability

The spectroscopic capabilities of a newly upgraded version of a prototype imaging photon counting detector (PCD) was investigated. The XCounter Actaeon has four acquisition modes in which signal processing is varied including one mode having a charge sharing correction so that neighboring pixels that share a detected event will not be erroneously counted twice, hence it is designated the Anti-Coincidence Circuit On or ACC On mode. Since this CdTe-based direct conversion PCD has 100 μm pixels, such charge sharing may frequently occur for typical medical x-ray energies. Each pixel of this PCD has two scalers and two energy discriminators that enable counting without instrumentation noise of events above each threshold level; hence, a spectrum can be obtained by sequentially moving the thresholds of both discriminators. It became evident from the spectra for the various acquisition modes that only those obtained with the charge sharing correction enabled, compared favorably with theoretically predicted spectra. After verifying the energy calibration using the mono-energetic emissions from an Am-241 source, spectra at various kVps from a standard medical x-ray generator were obtained. The spectra generated by ACC On mode for 70 kVp and 110 kVp were the closest match to the theoretical spectra generated by SpekCal. For dual energy applications, ACC On mode with charge sharing correction circuitry would be the best choice among various acquisition modes. Also investigated was the dual energy imaging capability of the Actaeon PCD with ACC On mode to separate Aluminum and Iodine while imaging an artery stenosis phantom.

Gantry rotational motion-induced blur in cone-beam computed tomography

As neuro-endovascular image-guided interventions (EIGIs) make use of higher resolution detectors, gantry rotational motion-induced blur becomes more noticeable in acquired projections as well as reconstructed images by reducing the visibility of vascular and device features whose visualization could be critical in the treatment of vascular pathology. Motion-induced blur in projections views is a function of an object's position in the field-of-view (FOV), gantry rotational speed, and frame capture or exposure time. In this work different frame rates were used to investigate the effects of blurring from individual projections on the reconstructed image. To test the effects of these parameters on reconstructed images, a regular pattern phantom of small objects was simulated and projection views were generated at various different frame rates for a given simulated rotational velocity. The reconstruction was made using a linear interpolation of filtered backprojections. Images reconstructed from lower frame rates showed significant blurring in the azimuthal direction, increasingly worse towards the periphery of the image. However, those reconstructed from higher frame rates showed significantly less blur throughout the entire FOV. While lower frame rates could be used with slower gantry speeds this would increase the risk of voluntary or involuntary patient motion contributing to blur over the entire FOV. A high frame rate used with high gantry speeds could reliable provide images without gantry-motion blur while reducing the risk of patient-motion blur. Frame rates exceeding 2000 fps available with photon counting detectors such as the X-counter Actaeon¹ are available.

Evaluation of a new photon-counting imaging detector (PCD) with various acquisition modes

The prospect of improved low noise, high speed, and dual-energy imaging that may be associated with the use of photon-counting imaging detectors (PCD) has motivated this evaluation of a newly upgraded version of a prototype PCD. The XCounter Actaeon was evaluated in its four acquisition modes each based upon varying signal processing firmware including a mode with charge sharing correction that enables neighboring pixels that share the energy from one incident x-ray photon detection to be counted only once at the proper summed energy in the pixel with the largest charge deposition. Since this PCD is a CdTe-based direct detector with 100 μm pixels, such charge sharing for typical medical x-ray energy photons may occur frequently and must be corrected to achieve more accurate counts. This charge sharing correction is achieved with an Anti-Coincidence Circuit (ACC) which prevents double pixel counting from one event as well as prevents counting from either event if they are below a preset threshold. Various physical parameters of the PCD were evaluated including linearity, sensitivity, pulse pile-up effects, dark noise, spatial resolution, noise power spectrum, and detective quantum efficiency.

The effects of antimuscarinic treatment on the cognition of spinal cord injured individuals with neurogenic lower urinary tract dysfunction: a prospective controlled before-and-after study

STUDY DESIGN

Prospective controlled before-and-after study.

OBJECTIVES

To investigate the effects of antimuscarinic treatment of neurogenic lower urinary tract dysfunction on the cognition of individuals with spinal cord injury (SCI) during the early post-acute phase.

SETTING

Single SCI rehabilitation center.

METHODS

Patients with acute traumatic SCI admitted for primary rehabilitation from 2011 to 2015 were screened for study enrollment. Study participants underwent baseline neuropsychological assessments prior to their first urodynamic evaluation (6-8 weeks after SCI). Individuals suffering from neurogenic detrusor overactivity received antimuscarinic treatment, and those not requiring antimuscarinic treatment constituted the control group. The neuropsychological follow-up assessment was carried out 3 months after the baseline assessment. The effects of group and time on the neuropsychological parameters were investigated.

RESULTS

The data of 29 individuals were evaluated (control group 19, antimuscarinic group 10). The group had a significant (P≤0.033) effect on immediate recall, attention ability and perseveration. In the control group, individuals performed significantly (P≤0.05) better in immediate recall both at baseline (percentile rank 40, 95% CI 21-86 versus 17, 95% CI 4-74) and follow-up (percentile rank 40, 95% CI 27-74 versus 16, 95% CI 2-74). The time had a significant (P≤0.04) effect on attention ability, processing speed, word fluency and visuospatial performance. The individuals in both groups performed better at the follow-up compared to the baseline assessment.

CONCLUSION

Even though, we did not observe cognitive deterioration in the investigated, cognitively intact SCI individuals during the first 3 treatment months, the concerns regarding deleterious effects of antimuscarinics on cognition remain.

Cast aluminium single crystals cross the threshold from bulk to size-dependent stochastic plasticity

Metals are known to exhibit mechanical behaviour at the nanoscale different to bulk samples. This transition typically initiates at the micrometre scale, yet existing techniques to produce micrometre-sized samples often introduce artefacts that can influence deformation mechanisms. Here, we demonstrate the casting of micrometre-scale aluminium single-crystal wires by infiltration of a salt mould. Samples have millimetre lengths, smooth surfaces, a range of crystallographic orientations, and a diameter D as small as 6 μm. The wires deform in bursts, at a stress that increases with decreasing D. Bursts greater than 200 nm account for roughly 50% of wire deformation and have exponentially distributed intensities. Dislocation dynamics simulations show that single-arm sources that produce large displacement bursts halted by stochastic cross-slip and lock formation explain microcast wire behaviour. This microcasting technique may be extended to several other metals or alloys and offers the possibility of exploring mechanical behaviour spanning the micrometre scale.

Risk factors for symptomatic urinary tract infections in individuals with chronic neurogenic lower urinary tract dysfunction

STUDY DESIGN

Retrospective investigation.

OBJECTIVES

To investigate the association of patient and injury characteristics, as well as bladder management, with the occurrence of patient-reported, symptomatic urinary tract infection(s) UTI(s) in patients with chronic neurogenic lower urinary tract dysfunction (NLUTD).

SETTING

Tertiary urologic referral center.

METHODS

The patient database was screened for patients with chronic (>12 months) NLUTD who had presented between 2008 and 2012. Patient characteristics, bladder evacuation management, the annual number of patient-reported, symptomatic UTIs and the type of prophylactic treatment to prevent UTIs were collected. Binary logistic regression analysis was used to investigate the effects of the investigated risk factors on the occurrence of symptomatic UTI(s) and recurrent symptomatic UTIs (⩾3 annual UTIs).

RESULTS

The data of 1104 patients with a mean NLTUD duration of 20.3±11.6 years were investigated. The evacuation method was a significant (P⩽0.004) predictor for the occurrence of symptomatic UTI and recurrent symptomatic UTIs. The greatest annual number of symptomatic UTIs was observed in patients using transurethral indwelling catheters, and the odds of experiencing a UTI and recurrent UTIs were increased more than 10- and 4-fold, respectively. The odds of a UTI or recurrent UTIs were also increased significantly (P⩽0.014) in patients using intermittent catheterization (IC). Botulinum toxin injections into the detrusor increased the odds of a UTI ~10-fold (P=0.03).

CONCLUSIONS

The bladder evacuation method is the main predictor for symptomatic UTIs in individuals with NLUTD. Transurethral catheters showed the highest odds of symptomatic UTI and should be avoided whenever possible.

Testicular resistive index determined by Doppler ultrasonography in men with spinal cord injury - a case series

In this case series, the testicular resistive index was determined in men with spinal cord injury. In ten men participating in our fertility programme, the peak systolic and end-diastolic velocity of centripetal testicular arteries was measured in triplicates by Doppler ultrasonography to calculate the testicular resistive index. Furthermore, the right and left testicular volume was determined by ultrasonography, blood samples were obtained for hormonal evaluation, and sperm analysis was performed according to the WHO guidelines. The median testicular resistive index measured 0.69 and was significantly (P < 0.001) greater than the reported cut-off value of 0.6. The spermiograms were characterised by normal sperm count but decreased sperm motility and plasma membrane integrity. The median right and left testicular volume was significantly (P < 0.01) smaller compared to the volumes measured in able-bodied adult males without scrotal pathology and measured 8.4 ml and 7.2 ml respectively. There was a significant (P = 0.005) correlation (rs  = 0.81) between testicular resistive index and sperm concentration. However, no correlations were observed between testicular resistive index and other variables. The testicular resistive index in men with spinal cord injury was significantly greater than 0.6. Measuring the testicular resistive index may represent a useful additional parameter in the assessment of infertility in spinal cord-injured men.

Release of ANP and fat oxidation in overweight persons during aerobic exercise in water

Exercise in water compared to land-based exercise (LE) results in a higher release of natriuretic peptides, which are involved in the regulation of exercise-induced adipose tissue lipolysis. The present study was performed to compare the release of atrial natriuretic peptide (ANP) and free fatty acids (FFA) during prolonged aerobic water-based exercise (WE) with the release after an identical LE. 14 untrained overweight subjects performed 2 steady state workload tests on the same ergometer in water and on land. Before and after exercise, venous blood samples were collected for measuring ANP, FFA, epinephrine, norepinephrine, insulin and glucose. The respiratory exchange ratio (RER) was determined for fat oxidation.The exercises resulted in a significant increase in ANP in LE (61%) and in WE (177%), and FFA increased about 3-fold in LE and WE with no significant difference between the groups. Epinephrine increased, while insulin decreased similarly in both groups. The RER values decreased during the exercises, but there was no significant difference between LE and WE. In conclusion, the higher ANP concentrations in WE had no additional effect on lipid mobilization, FFA release and fat oxidation. Moderate-intensity exercises in water offer no benefit regarding adipose tissue lipolysis in comparison to LE.

Effects of solifenacin in patients with neurogenic detrusor overactivity as a result of spinal cord lesion

STUDY DESIGN

Retrospective analysis.

OBJECTIVES

To investigate the urodynamic effects of solifenacin treatment for neurogenic detrusor overactivity (NDO) in patients with spinal cord injury (SCI).

SETTING

Paraplegic center in Switzerland.

METHODS

Retrospective analysis of case histories and urodynamic data of 35 SCI patients receiving solifenacin for treatment of NDO between 2008 and 2012. Patients were categorized as being at risk of renal damage when maximum detrusor pressure was >40 cm H2O or detrusor compliance was <20 ml cm(-1) H2O.

RESULTS

Solifenacin treatment was initiated 7.3 years after SCI. Most patients (63%) had already been taking other antimuscarinic drugs. After 13.1 months (median, interquartile range 6.1-19.5 months), solifenacin treatment had resulted in significant (P<0.03) improvements in bladder capacity (median +30.0 ml), maximum detrusor pressure (median -7.0 cm H2O), reflex volume (median +62.5 ml) and detrusor compliance (median +25.0 ml cm(-1) H2O). Furthermore, fewer patients presented with a risk of renal damage. However, this difference was not significant (P>0.1). The number of patients suffering from incontinence had not changed significantly. Eight and two patients discontinued solifenacin treatment as a result of insufficient efficacy and intolerable adverse events, respectively. One patient had discontinued solifenacin treatment without further explanation.

CONCLUSION

Solifenacin treatment significantly improved bladder capacity, detrusor compliance, reflex volume and maximum detrusor pressure. Solifenacin treatment seems to be an effective oral treatment of NDO after SCI.

120 THE DEVELOPMENTAL COMPETENCE OF TADPOLES PRODUCED IN VITRO FROM THE ENDANGERED DUSKY GOPHER FROG (RANA SEVOSA) USING EXOGENOUS HORMONE TREATMENT

Dusky gopher frogs once existed throughout the states of Mississippi, Alabama and Louisiana. Presently, the USA Fish and Wildlife Service estimates that there are less than 100 frogs left in the wild, with almost all of these residing in a single pond in Mississippi, making the dusky gopher frog America's most endangered frog species. Their habitat has been threatened by residential and forestry development, as well as from fire suppression and the decline of gopher tortoises, whose burrows the frogs use for shelter. The USA Fish and Wildlife Service brought the first dusky gopher frogs into captivity in 2001 and they have been kept at the Memphis Zoo since 2003 and at Omaha's Henry Doorly Zoo since 2004. Natural breeding attempts in captivity have been unsuccessful despite efforts to artificially mimic what is known to be the appropriate seasonal environmental (e.g. light, humidity, temperature) and social cues (e.g. calls from wild frogs during the breeding season) that stimulate reproduction in situ. Also, there was a concern about the incidences of abnormalities (e.g. spindly legs) from inadequate husbandry conditions (e.g. nutritional deficiencies) or diseases in tadpoles and froglets produced ex situ (e.g. dermomycoides). The objectives of this study were (1) to examine the developmental competence of tadpoles produced by exogenous hormone treatment for IVF to complete normal metamorphosis into viable froglets ex situ and (2) to determine the incidence of developmental abnormalities or dermomycoides in the froglets produced ex situ. Males and females were first separated by the identification of black male nuptial pads used during amplexus. Males and females were stimulated to spermiate and ovulate, respectively, using a variation of a standard amphibian hormonal stimulation protocol (Kouba et al. 2012 Reprod. Fertil. Dev. 24). As a result, more than 1460 viable tadpoles (61% of fertilized eggs) were produced from 18 segregated genetic pairings. To date, 602 (41%) of the tadpoles have completed normal metamorphosis into viable froglets (over 6 times the known existing population in situ), 51% were either culled to examine for dermomycoides or died for a variety of known (accidental) and unknown reasons (abnormal appendage development accounting for less than 7%) and 8% have yet to metamorphose after 9 months. The incidence of dermomycoides in the culled individuals was 100%; however, a study being conducted concurrently in their native habitat has confirmed that the organism does exist in situ with the dusky gopher frogs, which act as natural carriers. Efforts are currently in place to establish reintroduction programs for the dusky gopher froglets produced ex situ to increase the dwindling wild population now that tadpoles produced by IVF have been shown to be developmentally competent. In conclusion, IVF can be used to produce tadpoles of the dusky gopher frog with a low incidence of abnormalities, but the tadpoles were found to be carriers of the organism dermomycoides similar to their counterparts in the wild.

116 DEVELOPMENT OF ASSISTED REPRODUCTION TECHNOLOGIES FOR THE ENDANGERED MISSISSIPPI GOPHER FROG (RANA SEVOSA) AND SPERM TRANSFER FOR IN VITRO FERTILIZATION

Species-specific differences in breeding strategies and physiology have limited the application of assisted reproductive technologies (ART) for critically endangered amphibians in captive assurance colonies. In 2006, the Memphis Zoo (MZ) initiated a program to develop ART for the critically endangered Mississippi gopher frog after natural breeding failed. Standard gamete collection and IVF developed by MZ for reproducing endangered toads such as the Wyoming or boreal toad were applied to the gopher frog with little success, especially hormonal therapy for sperm production. Using the leopard frog as a model species for Ranids, we tested the time and dose dependence of a luteinizing hormone releasing hormone analogue (LHRHa) and hCG on sperm quantity and quality. Initial findings from the leopard frog study were critical in designing the study on gopher frogs. Our objectives were to (1) compare 2 different hormones administered intraperitoneal (500 IU hCG vs 15 μg LHRHa) or their combination on spermiation in gopher frogs; (2) develop in vivo oocyte maturation and ovulation protocols using LHRHa (15 μg) and hCG (500 IU); and (3) transfer this technology to another institution as proof of principle. In gopher frogs, 100 and 83% of the males produced sperm in response to the LHRHa and the combination treatment, respectively, whereas only 16% responded to hCG alone. Sperm concentration peaked at 1 h post-administration for all treatments, with the LHRH/hCG cocktail treatment producing the highest concentration of sperm (mean = 4.6 × 106 ± 1.2 × 106 sperm mL–1, n = 6). No differences in motility were observed between treatments (P > 0.05). For females, a series of priming hormones of hCG and LHRHa were given several months before an ovulatory hormone regimen resulting in ovulation by 100% of the females (n = 6), whereas animals not primed failed to ovulate (n = 4). These 3 separate priming and IVF trials conducted between 2008 and 2010 resulted in each female laying ∼2000 eggs, with an average fertilization rate of 76% for inseminated eggs and hundreds of tadpoles produced. These IVF tadpoles represent the first captive reproduction of gopher frogs and highlight how ART can be applied to conservation and genetic management of threatened species. Subsequently, we tested our IVF protocols on gopher frogs at Omaha's Henry Doorly Zoo using fresh (collected on site) and chilled, shipped sperm from MZ. We collected 6169 eggs from 9 hormone-primed females with all animals ovulating. A portion of the total eggs ovulated were inseminated, resulting in 2401 fertilized eggs (38.9% of total eggs collected) across 18 different male–female pairings leading to viable tadpoles. In addition, sperm transferred overnight from the MZ produced 202/441 fertilized eggs (46%). The transfer of this technology and production of endangered amphibians using chilled, shipped sperm from live animals is a conservation milestone that can be applied to other captive breeding programs.

Aerosolized semifluorinated alkanes as excipients are suitable for inhalative drug delivery--a pilot study

Semifluorinated alkanes (SFAs) have been described as potential excipients for pulmonary drug delivery, but proof of their efficacy is still lacking. We tested whether SFA formulations with the test drug ibuprofen can be nebulised and evaluated their pharmacokinetics. Physico-chemical properties of five different ibuprofen formulations were evaluated: an aqueous solution (H2O), two different SFAs (perfluorohexyloctane (F6H8), perfluorobutylpentane (F4H5)) with and without ethanol (SFA/EtOH). Nebulisation was performed with a jet catheter system. Inhalative characteristics were evaluated by laser diffraction. A confirmative animal study with an inhalative single-dose (6 mg/kg) of ibuprofen with each formulation was performed in anaesthetised healthy rabbits. Plasma samples at defined time points and lung tissue harvested after the 6-h study period were analyzed by HPLC-MS/MS. Pharmacokinetics were calculated using a non-compartment model. All formulations were nebulisable. No differences in aerodynamic diameters (MMAD) were detected between SFA and SFA/EtOH. The ibuprofen plasma concentration-time curve (AUC) was highest with F4H5/EtOH. In contrast, F6H8/EtOH had the highest deposition of ibuprofen into lung tissue but the lowest AUC. All tested SFA and SFA/EtOH formulations are suitable for inhalation. F4H5/EtOH formulations might be used for rapid systemic availability of drugs. F6H8/EtOH showed intrapulmonary deposition of the test drug.

Semifluorinated alkanes--a new class of excipients suitable for pulmonary drug delivery

INTRODUCTION

Semifluorinated alkanes (SFAs) are considered as diblock molecules with fluorocarbon and hydrocarbon segments. Unlike Perfluorocarbons (PFCs), SFAs have the potential to dissolve several lipophilic or water-insoluble substances. This makes them possibly suitable as new excipients for inhalative liquid drug carrier systems.

PURPOSE

The aim of the study was to compare physico-chemical properties of different SFAs and then to test their respective effects in healthy rabbit lungs after nebulisation.

METHODS

Physico-chemical properties of four different SFAs, i.e. Perfluorobutylpentane (F4H5), Perfluorohexylhexane (F6H6), Perfluorohexyloctane (F6H8) and Perfluorohexyldodecane (F6H12) were measured. Based on these results, aerosol characteristics of two potential candidates suitable as excipients for pulmonary drug delivery, i.e. F6H8 and F4H5, were determined by laser light diffraction. Tracheotomised and ventilated New Zealand White rabbits were nebulised with either a high- or a low dose of SFAs (F6H8(low/high) and F4H5(low/high)) or saline (NaCl). Ventilated healthy animals served as controls (Sham). Arterial blood gases, lung mechanics, heart rate and blood pressure were recorded prior to nebulisation and in 30 min intervals during the 6-h study period.

RESULTS

Out of the four SFAs studied initially, no satisfactory behaviour as a solvent has to be expected because of low lipophilicity for F6H6. Output rate during aerosolisation was very low for F6H12. F6H8 and F4H5 presented comparable aerosolisation characteristics and lipophilicity and were therefore tested in the in vivo model. Aerosol therapy, either SFAs or saline, impaired paO2/FiO2 ratio, dynamic lung compliance and respiratory mechanics in all groups, except for F4H5(low) group which behaved like the control group (Sham). F4H5(low) had no adverse effects on gas exchange or pulmonary mechanics.

CONCLUSIONS

Perfluorobutylpentane (F4H5) in a low-dose application may be suitable as a new inhalable excipient in SFA-based pulmonary drug delivery systems for lipophilic or water-insoluble substances.

The bioclimatic envelope of the wolverine (Gulo gulo): do climatic constraints limit its geographic distribution?

We propose a fundamental geographic distribution for the wolverine ( Gulo gulo (L., 1758)) based on the hypothesis that the occurrence of wolverines is constrained by their obligate association with persistent spring snow cover for successful reproductive denning and by an upper limit of thermoneutrality. To investigate this hypothesis, we developed a composite of MODIS classified satellite images representing persistent snow cover from 24 April to 15 May, which encompasses the end of the wolverine’s reproductive denning period. To investigate the wolverine’s spatial relationship with average maximum August temperatures, we used interpolated temperature maps. We then compared and correlated these climatic factors with spatially referenced data on wolverine den sites and telemetry locations from North America and Fennoscandia, and our contemporary understanding of the wolverine’s circumboreal range. All 562 reproductive dens from Fennoscandia and North America occurred at sites with persistent spring snow cover. Ninety-five percent of summer and 86% of winter telemetry locations were concordant with spring snow coverage. Average maximum August temperature was a less effective predictor of wolverine presence, although wolverines preferred summer temperatures lower than those available. Reductions in spring snow cover associated with climatic warming will likely reduce the extent of wolverine habitat, with an associated loss of connectivity.

161 CRYOPRESERVATION OF CORN SNAKE, ELAPHE GUTATTA, SEMEN

The purpose of this investigation was to develop a protocol for cryopreserving snake semen using the corn snake, Elaphe gutatta, as the model species. This experiment is part of a five year investigation where the influences of diluents, cryoprotectants, cooling and thawing rates on sperm survival were studied. This report presents one protocol found to be effective for cryopreserving corn snake semen as determined by post-thaw motility parameters in vitro. Semen was collected by applying pressure to the lower abdomen and continuing distally towards the cloaca to remove any feces or urates. The cloaca was washed using PBS, then a more local pressure was applied to each side of the vent to cause the hemipenes to evert and subsequently ejaculate. The semen (approximately 5 μL) was then collected using a sterile transfer pipette, placed in 120 μL Biladyl A containing 20% egg yolk (Minitube, 13502/0501), and analyzed for motility, rate of forward progression (RFP; 0–5), and concentration. The semen was further diluted at room temperature at 1:1 v/v with Biladyl A containing 20% egg yolk and 34% Glycerol (Sigma, G2025), yielding a final concentration of 17% Glycerol. The diluted semen was then loaded into 250-μL straws and slowly cooled for 1 hour. The straws were then placed 1 inch above a liquid nitrogen bath for ten minutes and finally plunged into the nitrogen where it remained frozen. The cryopreserved semen was thawed by placing the straws into a 50°C water bath for 8 s, then emptied into microcentrifuge tubes and the sperm were evaluated for motility and RFP. The mean motility of the fresh samples was 72.5% (66.4–77.7%). The mean post-thaw motility of sperm over six trials was 27.1% (17.8–50.2%). The mean RFP was 0.75 (0.5–1.0). The differences between fresh and post-thawed mean motilities were shown to be significant using a chi-square analysis (P < 0.0001). Density gradient centrifugation (DGC) was applied in one trial where the semen had an initial post-thaw motility of 50.2% with an RFP of 0.5. After the centrifugation treatment, the motility increased to 64.8% with an RFP of 3. The DGC media was composed of 400 μL 45% Percoll (Sigma, P4937) layered over 400 μL 90% Percoll. The density gradients were centrifuged at 700g for 30 min after which time the pellets were washed in 500 μL pre-warmed TL Hepes Solution (Lonza, 04-616F) and centrifuged at 300g for 10 min to remove the Percoll. The resulting sperm pellets were then resuspended in a small volume of the pre-warmed Hepes. Thus far, the protocol using 17% Glycerol in Biladyl A with 20% egg yolk has proven to be the most successful for cryopreserving corn snake semen. The use of DGC enhanced the number of usable sperm leaving sperm of higher motility and RFP possibly due to the absence of seminal plasma or cryoprotective agents that may detrimentally affect sperm quality. There are no known reports of the use of DCG with snake semen. Further studies are underway to improve these results and successfully use cryopreserved snake semen for artificial insemination and cryobanking for the long-term genetic management of endangered snake species.

Initial treatment with fixed-dose combination rosiglitazone/glimepiride in patients with previously untreated type 2 diabetes

AIM

This study assessed the efficacy and safety of two different dosing regimens of fixed-dose combination (FDC) rosiglitazone (RSG) plus glimepiride (GLIM) compared with RSG or GLIM monotherapy in drug-naive subjects with type 2 diabetes mellitus (T2DM).

METHODS

Drug-naive subjects (n = 901) were enrolled into this 28-week, double-blind, parallel-group study if their glycosylated haemoglobin A(1c) (HbA(1c)) was >7.5% but <or=12%. Subjects were randomized to receive either GLIM [4 mg once daily (OD) maximal], RSG (8 mg OD maximal) or RSG/GLIM FDC regimen A (4 mg/4 mg OD maximal) or RSG/GLIM FDC regimen B (8 mg/4 mg OD maximal). Patients were assessed for efficacy and safety every 4 weeks for the first 12 weeks of the study, and at weeks 20 and 28. The primary efficacy endpoint was change in HbA(1c) from baseline. Key secondary endpoints included the proportion of patients achieving recommended HbA(1c) and fasting plasma glucose (FPG) targets; change from baseline in FPG, insulin, C-reactive protein (CRP), adiponectin, free fatty acids and lipids; and percentage change in homeostasis model assessment-estimated insulin sensitivity and beta-cell function. Safety evaluations included adverse-event (AE) monitoring and clinical laboratory evaluations.

RESULTS

At week 28, both RSG/GLIM FDC regimens significantly reduced HbA(1c) (mean +/- s.d.: -2.4 +/- 1.4% FDC regimen A; -2.5 +/- 1.4% FDC regimen B) to a greater extent than RSG (-1.8 +/- 1.5%) or GLIM (-1.7 +/- 1.4%) monotherapy (model-adjusted mean treatment difference, p < 0.0001 vs. both RSG and GLIM). Significantly more subjects achieved HbA(1c) target levels of <or=6.5 and <7% with either RSG/GLIM FDC regimen compared with RSG or GLIM alone (model-adjusted odds ratio, p < 0.0001 for both comparisons). Similarly, a significantly greater reduction in FPG levels was observed in subjects treated with the RSG/GLIM FDC [mean +/- s.d. (mg/dl): -69.5 +/- 57.5 FDC regimen A; -79.9 +/- 56.8 FDC regimen B) compared with RSG (-56.6 +/- 58.1) or GLIM (-42.2 +/- 66.1) monotherapy (model-adjusted mean treatment difference, p < 0.0001 for both comparisons). Improvement in CRP was also observed in subjects who were treated with a RSG/GLIM FDC or RSG monotherapy compared with GLIM monotherapy. RSG/GLIM FDC was generally well tolerated, with no new safety or tolerability issues identified from its monotherapy components, and a similar AE profile was observed across FDC regimens. The most commonly reported AE was hypoglycaemia, and the incidence of confirmed symptomatic hypoglycaemia (3.6-5.5%) was comparable among subjects treated with an RSG/GLIM FDC and GLIM monotherapy.

CONCLUSIONS

Compared with RSG or GLIM monotherapy, the RSG/GLIM FDC improved glycaemic control with no significant increased risk of hypoglycaemia. RSG/GLIM FDC provides an effective and well-tolerated treatment option for drug-naive individuals with T2DM.

Plasma levels of endothelin-1 after a pulmonary embolism of bone marrow fat

BACKGROUND

During orthopedic surgery, embolization of bone marrow fat can lead to potentially fatal, intra-operative cardiovascular deterioration. Vasoactive mediators may also be released from the bone marrow and contribute to these changes. Increased plasma levels of endothelin-1 (ET-1) have been observed after pulmonary air and thrombo-embolism. The role of ET-1 in the development of acute cardiovascular deterioration as a result of bone marrow fat embolization during vertebroplasty was therefore investigated.

METHODS

Bone cement was injected into three lumbar vertebrae of six sheep in order to force bone marrow fat into the circulation. Invasive blood pressures and heart rate were recorded continuously until 60 min after the last injection. Cardiac output, arterial and mixed venous blood gas parameters and plasma ET-1 concentrations were measured at selected time points. Post-mortem, lung biopsies were taken for analysis of intravascular fat.

RESULTS

Cement injections resulted in a sudden (within 1 min) and severe increase in pulmonary arterial pressure (>100%). Plasma concentrations of ET-1 started to increase after the second injection, but no significant changes were observed. Intravascular fat and bone marrow cells were present in all lung lobes.

CONCLUSION

Cement injections into vertebral bodies elicited fat embolism resulting in subsequent cardiovascular changes that were characterized by an increase in pulmonary arterial pressure. Cardiovascular complications as a result of bone marrow fat embolism should thus be considered in patients undergoing vertebroplasty. No significant changes in ET-1 plasma values were observed. Thus, ET-1 did not contribute to the acute cardiovascular changes after fat embolism.

Cardiovascular changes after pulmonary cement embolism: an experimental study in sheep

BACKGROUND AND PURPOSE

Most cement leaks during vertebroplasty are asymptomatic, but pulmonary cement embolism has been reported to cause cardiovascular disturbances and even death. Adding hydroxyapatite (HA) to polymethylmethacrylate (PMMA) cement to reduce the quantity of barium may aggravate cardiovascular deterioration in the event of cement embolism by activating coagulation. Thus, we investigated the cardiovascular changes after pulmonary cement embolism of PMMA with and without HA.

MATERIALS AND METHODS

In 13 sheep, cement (2.0 mL) was injected into the pulmonary trunk. Two different cements were used: 1) standard PMMA and 2) PMMA with 10% HA (PMMA & HA). Arterial, central venous and pulmonary arterial pressures, heart rate, and cardiac output were monitored continuously until 60 minutes after the injection. Blood gases and coagulation parameters (antithrombin, D-dimer) were measured before and after injection.

RESULTS

Mean pulmonary arterial pressure had increased by approximately 9% (PMMA) and 14% (PMMA & HA) 1 minute after injection and stayed elevated. There were no significant differences between the groups. No evidence of thromboembolism was detected.

CONCLUSION

Cement embolism did not result in clinically significant pulmonary arterial hypertension. Adding HA to PMMA cement did not cause more severe cardiovascular changes.

247 SUCCESSFUL ARTIFICIAL INSEMINATION IN THE CORN SNAKE (ELAPHE GUTATTA), USING FRESH AND COOLED SEMEN

The purpose of this investigation was to develop a non-invasive technique to artificially inseminate snakes using the corn snake, Elaphe gutatta, as the model representative for this taxon. Semen was collected by first applying pressure to the lower abdomen in a continuous distal motion toward the cloaca to remove any feces or urates. The cloaca was then gently washed using phosphate-buffered saline, and a more localized pressure was applied to each side of the vent to evert the hemipenes and, subsequently, the ejaculate. The semen was collected using a sterile transfer pipette and placed into 70 to 90 �L of medium (TL-HEPES solution; Cambrex Bio Science, Inc., Baltimore, MD, USA04–616F) in a sterile microcentrifuge tube, and then analyzed for overall motility, rate of forward progression (RFP, 0–5), and concentration. Based on a previously reported procedure, 10 females were inseminated with either fresh (n = 5) or cooled semen (n = 5; refrigerated for 3 days) one week after recovering from a hibernation period required to stimulate reproduction in this species. The overall sperm motility and concentration for females inseminated with fresh or cooled semen was 92%, 9.6 million sperm mL-1; and 85%, 6.1 million sperm mL-1, respectively. Immediately prior to insemination, the same method for expressing feces and urates in the males was applied to the females. The insemination dose (50 �L semen per oviduct) was drawn into a 1-mL latex- and silicone-free tuberculin syringe (Norm-Ject; VWR, Batavia, IL, USA) that was connected to a feeding/dosing needle (EJAY International, Issaquah, WA, USA) with a ball tip to prevent any potential damage during the insemination. The tip of the needle was then moved around the inner tissue of the vent to relax the cloaca, and the insertion continued until resistance was found indicating the vicinity of the oviducts. The extended semen was carefully deposited on both sides, and then the needle was slowly withdrawn. The offspring were tested for parentage to verify the success of the insemination. Blood was collected from the dorsal aorta posterior to the cloaca and stored in 10 mM Tris at 4�C. The DNA was extracted using a phenyl : chloroform : isoamyl alcohol (PCI) extraction method. Eight microsatellite loci were used for the paternity exclusion analysis: Eob�1, Eob�3, Eob�10, Eob�13, Eob�16, Eob�34, Eob�366, and Eob�373 (IDT, Coraville, IA, USA). All males and females in the collection were tested, and parental candidates were excluded if 2 or more allele mismatches occurred. From the total number of females inseminated, 3 females laid 51 eggs. Two females inseminated with cooled semen laid 36 eggs, of which 5 eggs were hatched, and the remaining were either unfertilized (n = 25) or non-viable (n = 6). All 5 hatched eggs were laid by one of the females. The third female inseminated with fresh semen laid 15 eggs, resulting in 5 hatching and 10 unfertilized eggs. The parentage test validated the AI a success as the alleles correlated between the adults and the offspring. In conclusion, artificial insemination was successful using both freshly collected and cooled (3 days) semen. Further studies are underway to improve the success rate in order to maximize the efficiency of this technology, and thus assist in the genetic preservation of endangered snake species.

Abnormal glucose metabolism and features of the metabolic syndrome are common in patients presenting for elective cardiac catheterization

BACKGROUND

Abnormalities of glucose metabolism and the metabolic syndrome, including excess bodyweight, are potentially modifiable risk factors for cardiac morbidity and mortality. This study aimed to determine the prevalence of these in a group of patients presenting for elective cardiac catheterization or percutaneous intervention.

METHODS

Data were prospectively collected on 297 consecutive patients presenting for elective cardiac catheterization or percutaneous intervention at a single tertiary referral centre. Demographic data, risk factors, medications and coronary angiogram results were recorded. Fasting lipids, fasting glucose, HbA1c levels were measured and if necessary an oral glucose tolerance test was carried out. Logistic regression and contingency table analysis examined associations of these with ethnicity.

RESULTS

Impaired glucose metabolism (diabetes, impaired glucose tolerance or impaired fasting glucose) was present in 46.1% with our screening programme detecting previously unknown impaired glucose metabolism in 22.9%. Impaired glucose metabolism was strongly associated with non-European ethnicity (P < 0.0001). The metabolic syndrome was present in 49.2%. When defined by ethnic specific cut-offs, overweight or obesity was present in >80% of patients in all ethnic groups.

CONCLUSION

There is a very high prevalence of impaired glucose metabolism and the metabolic syndrome in patients presenting for cardiac catheterization. Impaired glucose metabolism is particularly prevalent in the Polynesian and the Indian and the Sri Lankan ethnic groups. Screening of patients undergoing elective cardiac catheterization identifies a significant number of patients with undiagnosed impaired glucose metabolism and should be carried out routinely.

Nuclear translocation of the calcium-binding protein ALG-2 induced by the RNA-binding protein RBM22

By yeast two-hybrid screening using the calcium-binding protein ALG-2 as bait a new target of ALG-2 was identified, the RNA-binding protein RBM22. In order to confirm these interactions in vivo we prepared fluorescent constructs by using the monomeric red fluorescent protein to label ALG-2 and the enhanced green fluorescent protein to label RBM22. Confocal microscopy of NIH 3T3 cells transfected with either ALG-2 or RBM22 expression constructs encoding fluorescent fusion proteins alone revealed that the majority of ALG-2 was localized in the cytoplasm whereas RBM22 was located in the nucleus. When cells were co-transfected with expression vectors encoding both fusion proteins ALG-2 was found in the nucleus indicating that RBM22 which can shuttle between the cytoplasm and the nucleus may play a role in nuclear translocation of ALG-2. Using zebrafish as a model mRNA homologues of ALG-2 and RBM22 were microinjected into the blastodisc-yolk margin of zebrafish embryos at the 1-cell stage followed by monitoring the fusion proteins during development of the zebrafish. Hereby, we observed that ALG-2 alone evenly distributed within the cell, whereas in the presence of RBM22 the two proteins co-localized within the nucleus. More than 95% of the two proteins co-localized within the same area in the nucleus suggesting a functional interaction between the Ca(2+)-signaling protein ALG-2 and the RNA-binding protein RBM22.

Degradation of hydroxyapatite coating on a well-functioning femoral component

We carried out a histological study of a proximally hydroxyapatite (HA)-coated femoral component, retrieved after 9.5 years of good function. The HA coating had completely degraded. Bone was in direct contact with the titanium surface in all the areas which had been coated, with no interposing fibrous tissue. There were no signs of particles, third-body wear, adverse tissue reactions or osteolysis. Bone remodelling was evident by the presence of resorption lacunae; tetracycline labelling showed bone laid down six years after implantation. The loss of the HA-coating had no negative effect on the osseo-integration of the stem. We conclude that the HA coating contributes to the fixation of the implant and that its degradation does not adversely affect the long-term fixation.

Comparative genomic hybridization analysis in adult T-cell leukemia/lymphoma: correlation with clinical course

Sixty-four patients with adult T-cell leukemia/lymphoma (ATL; 18 patients with indolent subtype and 46 with aggressive subtype) associated with human T-lymphotropic virus type 1 (HTLV-1) were analyzed using comparative genomic hybridization (CGH). The most frequent observations were gains at chromosomes 14q, 7q, and 3p and losses at chromosomes 6q and 13q. Chromosome imbalances, losses, and gains were more frequently observed in aggressive ATL than in indolent ATL, with significant differences between the 2 ATL subtypes at gains of 1q and 4q. An increased number of chromosomal imbalances was associated with a significantly shorter survival in all patients. A high number of chromosomal losses was associated with a poor prognosis in indolent ATL, whereas the presence of 7q+ was marginally associated with a good prognosis in aggressive ATL. Paired samples (ie, samples obtained at different sites from 4 patients) and sequential samples from 13 patients (from 6 during both chronic disease and acute crisis and from 7 during both acute onset and relapse) were examined by CGH and Southern blotting for HTLV-1. All but 2 paired samples showed differences on CGH assessment. Two chronic/crisis samples showed distinct results regarding both CGH and HTLV-1 integration sites, indicating clonal changes in ATL at crisis. In 11 patients, the finding of identical HTLV-1 sites and clonally related CGH results suggested a common origin of sequential samples. In contrast to chronic/crisis samples, CGH results with all acute/relapse sample pairs showed the presence of clonally related but not evolutional subclones at relapse, thereby suggesting marked chromosomal instability. In summary, clonal diversity is common during progression of ATL, and CGH alterations are associated with clinical course. (Blood. 2001;97:3875-3881)

The ALG-2/AIP-complex, a modulator at the interface between cell proliferation and cell death? A hypothesis

During the development of an organism cell proliferation, differentiation and cell death are tightly balanced, and are controlled by a number of different regulators. Alterations in this balance are often observed in a variety of human diseases. The role of Ca(2+) as one of the key regulators of the cell is discussed with respect to two recently discovered proteins, ALG-2 and AIP, of which the former is a Ca(2+)-binding protein, and the latter is substrate to various kinases. The two proteins interact with each other in a Ca(2+)-dependent manner, and the role of the complex ALG-2/AIP as a possible modulator at the interface between cell proliferation and cell death is discussed.

NMR solution structure of a complex of calmodulin with a binding peptide of the Ca2+ pump

The three-dimensional structure of the complex between calmodulin (CaM) and a peptide corresponding to the N-terminal portion of the CaM-binding domain of the plasma membrane calcium pump, the peptide C20W, has been solved by heteronuclear three-dimensional nuclear magnetic resonance (NMR) spectroscopy. The structure calculation is based on a total of 1808 intramolecular NOEs and 49 intermolecular NOEs between the peptide C20W and calmodulin from heteronuclear-filtered NOESY spectra and a half-filtered experiment, respectively. Chemical shift differences between free Ca(2+)-saturated CaM and its complex with C20W as well as the structure calculation reveal that C20W binds solely to the C-terminal half of CaM. In addition, comparison of the methyl resonances of the nine assigned methionine residues of free Ca(2+)-saturated CaM with those of the CaM/C20W complex revealed a significant difference between the N-terminal and the C-terminal domain; i.e., resonances in the N-terminal domain of the complex were much more similar to those reported for free CaM in contrast to those in the C-terminal half which were significantly different not only from the resonances of free CaM but also from those reported for the CaM/M13 complex. As a consequence, the global structure of the CaM/C20W complex is unusual, i.e., different from other peptide calmodulin complexes, since we find no indication for a collapsed structure. The fine modulation in the peptide protein interface shows a number of differences to the CaM/M13 complex studied by Ikura et al. [Ikura, M., Clore, G. M., Gronenborn, A. M., Zhu, G., Klee, C. B., and Bax, A. (1992) Science 256, 632-638]. The unusual binding mode to only the C-terminal half of CaM is in agreement with the biochemical observation that the calcium pump can be activated by the C-terminal half of CaM alone [Guerini, D., Krebs, J., and Carafoli, E. (1984) J. Biol. Chem. 259, 15172-15177].

Calmodulin-dependent protein kinase IV: regulation of function and expression

Calmodulin-dependent protein kinase IV (CaMKIV) is a key mediator of Ca2+-induced gene expression. This serine/threonine kinase is itself activated by a calmodulin kinase kinase. In the present contribution the gene structure, regulation of activity, the role in Ca2+-dependent gene expression, and the hormonal induction and controlled expression of CaMKIV during tissue development are reviewed.

The role of calcium in apoptosis

In this chapter various aspects of apoptosis or programmed cell death (PCD) influenced by calcium as a mediator of signal transduction have been reviewed. Attention has been focused on recently described calcium-binding proteins such as ALG-2 or on a new calcium/calmodulin-dependent kinase, the death associated protein kinase or DAP-kinase. Both play a central role in apoptotic processes. Calcineurin, which normally is involved in the regulation of T-cell proliferation, is reported to interact with the apoptosis protection protein bcl-2. Its possible involvement in the decision process whether T-cell activation leads to proliferation or apoptosis is discussed.

Calmodulin-dependent protein kinase IV during T-cell development

In a primary cell culture system of fetal rat brain, the calmodulin-dependent protein-kinase IV (CaMKIV) could be induced by the thyroid hormone T3 in a time- and concentration-dependent manner, provided the tissue was excised not later than day 15 of gestation (E15) (Krebs et al., J. Biol. Chem. 271, 11055, 1996). We report here that in the fetal thymus CaMKIV could not be detected earlier than day 16 of gestation and that the expression of this enzyme was fully upregulated at day 18. In mouse fetal thymus organ culture (FTOC) of day 14 embryonic thymus, CaMKIV could not be detected, even after several days of culture if a minimal culture medium lacking fetal calf serum was used. However, after addition of fetal calf serum to the culture medium the expression of CaMKIV could be specifically induced. Furthermore, it could also be shown that during T-cell development in the adult murine thymus the expression of CaMKIV was tightly regulated. Taken together, these results demonstrate that the expression of CaMKIV, an enzyme involved in the regulation of Ca(2+)-dependent gene expression, is itself under stringent regulatory control during tissue development.

Calmodulin kinase IV: expression and function during rat brain development

The expression of calmodulin kinase IV (CaMKIV) can be induced by the thyroid hormone T3 in a time- and concentration-dependent manner at a very early stage of brain differentiation using a fetal rat telencephalon primary cell culture system which can grow and differentiate under chemically defined conditions (Krebs et al. (1996) J. Biol. Chem. 271, 11055-11058). After the induction of CaMKIV by T3 we examined the influence of prolonged absence of T3 from the culture medium on the expression of CaMKIV. We could demonstrate that after the T3-dependent induction of CaMKIV, omission of the hormone, even for 8 days, from the medium did not downregulate the expression of CaMKIV indicating that different regulatory mechanisms became important for the expression of the enzyme. We further showed that CaMKIV could be involved in the Ca(2+) -dependent expression of the immediate early gene c-fos, probably via phosphorylation of the transcription factor CREB. Convergence of signal transduction pathways on this transcription factor by using different protein kinases may explain the importance of CREB for the regulation of different cellular processes.

In vitro activation of CPP32 and Mch3 by Mch4, a novel human apoptotic cysteine protease containing two FADD-like domains

Emerging evidence suggests that an amplifiable protease cascade consisting of multiple aspartate specific cysteine proteases (ASCPs) is responsible for the apoptotic changes observed in mammalian cells undergoing programmed cell death. Here we describe the cloning of two novel ASCPs from human Jurkat T-lymphocytes. Like other ASCPs, the new proteases, named Mch4 and Mch5, are derived from single chain proenzymes. However, their putative active sites contain a QACQG pentapeptide instead of the QACRG present in ail known ASCPs. Also, their N termini contain FADD-like death effector domains, suggesting possible interaction with FADD. Expression of Mch4 in Escherichia coli produced an active protease that, like other ASCPs, was potently inhibited (Kj = 14 nM) by the tetrapeptide aldehyde DEVD-CHO. Interestingly, both Mch4 and the serine protease granzyme B cleave recombinant proCPP32 and proMch3 at a conserved IXXD-S sequence to produce the large and small subunits of the active proteases. Granzyme B also cleaves proMch4 at a homologous IXXD-A processing sequence to produce mature Mch4. These observations suggest that CPP32 and Mch3 are targets of mature Mch4 protease in apoptotic cells. The presence of the FADD-like domains in Mch4 and Mch5 suggests a role for these proteases in the Fas-apoptotic pathway. In addition, these proteases could participate in the granzyme B apoptotic pathways.

Induction of calmodulin kinase IV by the thyroid hormone during the development of rat brain

This communication reports the specific induction of calmodulin kinase IV by the thyroid hormone 3,3',5-triiodo-L-thyronine (T3) in a time- and concentration-dependent manner at a very early stage of brain differentiation using a fetal rat telencephalon primary cell culture system, which can grow and differentiate under chemically defined conditions. The induction of the enzyme that can be observed both on the mRNA and on the protein level is T3-specific, i.e. it cannot be induced by retinoic acid or reverse T3, and can be inhibited on both the transcriptional and the translational level by adding to the culture medium actinomycin D or cycloheximide, respectively. The earliest detection of calmodulin kinase IV in the fetal brain tissue of the rat is at days E16/E17, both on the mRNA as well as on the protein level. This is the first report in which a second messenger-dependent kinase involved in the control of cell regulatory processes is itself controlled by a primary messenger, the thyroid hormone.

Current issues in rabies prevention in the United States health dilemmas. Public coffers, private interests

OVER THE LAST 100 years, rabies in the United States has changed dramatically. More than 90% of all animal rabies cases reported annually to the CDC now occur in wildlife, whereas before 1960 the majority were in domestic animals. The principal rabies hosts today are wild carnivores and bats infected with several viral variants. Annual human deaths have fallen from more than a hundred at the turn of the century to one to two per year despite major outbreaks of animal rabies in several geographic areas. Modern day prophylaxis has proven nearly 100% successful; most human fatalities now occur in people who fail to seek medical treatment, usually because they do not recognize a risk in the animal contact leading to the infection. Although these human rabies deaths are rare, the estimated public health costs associated with disease detection, prevention, and control have risen, exceeding millions of dollars each year. Cost considerations must be weighed along with other factors in addressing issues such as the appropriate handling of nontraditional and exotic pets, future guidelines for rabies prophylaxis, and novel methods of disease prevention.