TRACE observation of damped coronal loop oscillations: implications for coronal heating

The imaging telescope on board the Transition Region and Coronal Explorer (TRACE) spacecraft observed the decaying transversal oscillations of a long [(130 +/- 6) x 10(6) meters], thin [diameter (2.0 +/- 0.36) x 10(6) meters], bright coronal loop in the 171 angstrom Fe(IX) emission line. The oscillations were excited by a solar flare in the adjacent active region. The decay time of the oscillations is 14.5 +/- 2.7 minutes for an oscillation with a frequency 3.90 +/- 0.13 millihertz. The coronal dissipation coefficient is estimated to be eight to nine orders of magnitude larger than the theoretically predicted classical value. The larger dissipation coefficient may solve existing difficulties with wave heating and reconnection theories.

Chronic systemic administration of tumor necrosis factor alpha and HIV gp120: effects on adult rodent brain and blood-brain barrier

Since tumor necrosis factor alpha (TNF-alpha) and HIV gpl20 glycoprotein are both neurotoxic, the possibility that systemic sources of these two agents mediate AIDS-associated blood-brain barrier (BBB) breakdown and brain damage was tested in two murine models: (1) intramuscular implantation of a TNF-alpha-transfected tumor in nu/nu mice and (2) daily subcutaneous injections of HIV gpl20 in BALB/c mice. The BBB remained intact; brain damage was not found, and apoptotic cell numbers did not increase. These results show that normal adult brain and BBB is unaffected by exposure to TNF-alpha or HIV gpl20 and suggest that severity of brain disease is not directly affected by systemic levels of these compounds.

Immunizing patients with metastatic melanoma using recombinant adenoviruses encoding MART-1 or gp100 melanoma antigens

BACKGROUND

The characterization of the genes encoding melanoma-associated antigens MART-1 or gp100, recognized by T cells, has opened new possibilities for the development of immunization strategies for patients with metastatic melanoma. With the use of recombinant adenoviruses expressing either MART-1 or gp100 to immunize patients with metastatic melanoma, we evaluated the safety, immunologic, and potential therapeutic aspects of these immunizations.

METHODS

In phase I studies, 54 patients received escalating doses (between 10(7) and 10(11) plaque-forming units) of recombinant adenovirus encoding either MART-1 or gp100 melanoma antigen administered either alone or followed by the administration of interleukin 2 (IL-2). The immunologic impact of these immunizations on the development of cellular and antibody reactivity was assayed.

RESULTS

Recombinant adenoviruses expressing MART-1 or gp100 were safely administered. One of 16 patients with metastatic melanoma receiving the recombinant adenovirus MART-1 alone experienced a complete response. Other patients achieved objective responses, but they had received IL-2 along with an adenovirus, and their responses could be attributed to the cytokine. Immunologic assays showed no consistent immunization to the MART-1 or gp100 transgenes expressed by the recombinant adenoviruses. High levels of neutralizing antibody were found in the pretreatment sera of the patients.

CONCLUSIONS

High doses of recombinant adenoviruses could be safely administered to cancer patients. High levels of neutralizing antibody present in patients' sera prior to treatment may have impaired the ability of these viruses to immunize patients against melanoma antigens.

The central and renal hemodynamic effects of amino acid infusion in the study of renal reserve in the baboon

Normal human renal function is characterized by a large renal reserve. Recruitment of this reserve is a compensatory and pathological response to renal injury. This study was designed to assess the renal reserve and central hemodynamics of young female baboons and, in doing so, the appropriateness of the use of these animals in a model of human renal disease. Eight female baboons completed the protocol. PAH and inulin clearances were measured before and after an amino acid infusion. Central hemodynamics were measured with arterial and pulmonary artery catheters. Effective renal plasma flow and glomerular filtration rate increased by 42% after amino acid infusion (P = .025). Expansion of renal function was not consistent among individual baboons; two of the eight animals did not demonstrate renal reserve. Central hemodynamics were unaffected by the protocol.

Profiling the perceptual suppression of partials in periodic complex tones: further evidence for a harmonic template

The basis for the perceptual cohesion of periodic complex tones was investigated. In experiment 1, 2-4 consecutive components (harmonics 6 and above) were removed from a 14-harmonic complex and replaced with a sinusoidal "probe," located at one of a set of regularly spaced positions spanning the gap. On each trial, subjects heard a complex tone followed by an adjustable pure tone in a continuous loop. Subjects were better able to match the pure tone to the probe when the probe did not coincide with a harmonic position. Minima in "hit rate" were more pronounced when harmonic probes were in positions adjacent to other harmonics than when they were not. These findings suggest that the pitch of each in-tune partial was actively suppressed by a template whose influence attenuated with distance from regions of consecutive harmonics. In experiment 2, the partials on either side of the spectral gap were harmonics of different fundamental frequencies. Hit-rate minima corresponding to both fundamentals were found, indicating an upward and downward spread of suppression, and also demonstrating the concurrent operation of two templates. The results confirm recent findings in support of template models, and are consistent with the idea that partial-pitch suppression underpins harmonic fusion.

Export controls and biological weapons: new roles, new challenges

This article considers the value of export controls in reducing the threat of biological weapons. It concludes that export control through export licensing is an essential element in the overall strategy to limit the spread of biological weapons. Modifications to existing export control systems can maximize the usefulness of export controls for limiting the threat of biological warfare and bioterrorism. Export controls are useful only within a broader strategy that includes both an arms control dimension and military defensive preparedness.

Perceptual segregation and pitch shifts of mistuned components in harmonic complexes and in regular inharmonic complexes

It is unclear whether the perceptual segregation of a mistuned harmonic from a periodic complex tone depends specifically on harmonic relations between the other components. A procedure used previously for harmonic complexes [W. M. Hartmann et al., J. Acoust. Soc. Am. 88, 1712-1724 (1990)] was adapted and extended to regular inharmonic complexes. On each trial, subjects heard a 12-component complex followed by a pure tone in a continuous loop. In experiment 1, a mistuning of +/- 4% was applied to one of the components 2-11. The complex was either harmonic, frequency shifted, or spectrally stretched. Subjects adjusted the pure tone to match the pitch of the mistuned component. Near matches were taken to indicate segregation, and were almost as frequent in the inharmonic conditions as in the harmonic case. Also, small but consistent mismatches, pitch shifts, were found in all conditions. These were similar in direction and size to earlier findings for harmonic complexes. Using a range of mistunings, experiment 2 showed that the segregation of components from regular inharmonic complexes could be sensitive to mistunings of 1.5% or less. These findings are consistent with the proposal that aspects of spectral regularity other than harmonic relations can also influence auditory grouping.

Long-term Doppler echocardiographic results of aortic or mitral valve replacement with Biocor porcine bioprosthesis

OBJECTIVES

Our objectives were to evaluate the long-term bioprosthetic and cardiac functional outcome after insertion (over a 10-year period) of a new-generation porcine zero pressure-fixed Biocor bioprosthesis, as well as to determine the echocardiographic accuracy for selection of patients requiring reoperation. The long-term systematic Doppler echocardiographic assessment after valve replacement with this bioprosthesis is lacking.

METHODS

Between January 1983 and January 1993, we inserted 756 Biocor prostheses in the aortic (619) or mitral (137) positions. All 51 patients who had a reoperation during the follow-up time were evaluated echocardiographically before reoperation. Additionally, 263 of 446 patients (59%) with aortic bioprostheses and 42 of 74 patients (57%) with mitral bioprostheses who were alive in January 1993 had long-term echocardiographic follow-up.

RESULTS

Group A: Normally functioning bioprostheses were found in the aortic position in 242 of 263 patients and in the mitral position in 33 of 42 patients. Group B: Thirty patients had abnormal bioprosthetic function. Eleven patients had regurgitation, 3 had a combined lesion, and signs of calcification appeared in 16 patients with aortic valves, all with a peak gradient of above 60 mm Hg. Group C: Patients who had a reoperation (41 aortic and 10 mitral) within the follow-up period were followed up echocardiographically from the detection of a possible valve dysfunction until reoperation, and the findings accorded well with those at operation in 49 of 51 patients.

CONCLUSIONS

These findings suggest that, during a long-term follow-up, most bioprostheses function normally, facilitating improved heart function. Abnormalities in a bioprosthesis usually develop gradually, enabling their detection by Doppler echocardiographic evaluations performed regularly or in case of any symptomatic deterioration.

DAN is a secreted glycoprotein related to Xenopus cerberus

We report that DAN, a potential cell cycle regulator and tumour suppressor, is a secreted glycoprotein related to Xenopus cerberus. DAN, cerberus, its mouse relative Cer-1/cer-l/Cerberus-like/Cerr1, and the recently described factor DRM/Gremlin, appear to be members of the cystine knot superfamily, which includes TGFbetas and BMPs. Like cerberus and mCer-1, DAN-induced cement glands as well as markers of anterior neural tissue and endoderm in Xenopus animal cap assays, features of BMP signalling blockade. During mouse embryogenesis, Dan was expressed from E8.5 in cranial mesenchyme and somites, then later in limb and facial mesenchyme. The pattern in somites was highly dynamic, with transcripts initially localized to the caudal half of the nascent epithelial somite, then, after maturation, to sclerotomal cells adjacent to the neural tube. Dan was also expressed in the developing myotome. The expression domains include sites in which BMP inhibition is known to be important for development. Thus, DAN appears to be a secreted factor belonging to the cystine knot superfamily, and one of a growing number of antagonists acting to modulate BMP signalling during development.

An evolving continuous quality improvement role for managed care: a behavioral healthcare perspective

Managed care's initial continuous quality improvement impact may have been comparable to the sentinel, or Hawthorne, effect. Managed behavioral healthcare's CQI role can be compared with that of the clinical navigator. The clinical navigator attempts to develop a consensus with the patient on what is the clinical destination, and must choose a route to travel that is the best approach to reach the destination (i.e., a focused treatment plan). In addition, the clinical navigator tries to find the most efficient mode of travel--or, the least restrictive, least intrusive site of care from where the patient can receive treatment. Essential clinical tasks or expectations in the clinical assessment are also outlined, and the concept of knowledge coupling is introduced to accommodate the unique, individual issues of the patient. The emphasis of managed care today is shifting to further accentuate a CQI, outcomes-based approach.

Use of a cast flexible plate as a hinge substitute in a hinge-lock design removable partial denture framework

PURPOSE

The use of a hinge for a removable partial denture with an opening labial bow was replaced by the design and construction of a flexible plate incorporated as part of a cobalt-chromium casting.

METHODS

Three similar prostheses were constructed and tested in vitro on an endurance test machine. Each test piece completed 12,000 opening and closing operations without fracture, which a previous study showed is a probable life cycle of a typical removable partial denture with a hinged section.

RESULTS

This plate provided sufficient flexibility to allow functional operation of the removable partial denture by a patient.

The mechanism of retroviral recombination: the role of sequences proximal to the point of strand transfer

Transfer of nascent DNA from an RNA template (donor) to the homologous region of a second RNA template (acceptor) was studied. The templates were designed to assess the roles of the sequences proximal (3' relative to the transferring DNA) to the point of transfer. The donor template was primed with a specific 18 nucleotide DNA such that extension by reverse transcriptase to the end of the template produced a 79 nucleotide product. Homologous strand transfer and subsequent extension on the acceptors produced longer products allowing distinction between strand transfer and donor-directed synthesis. The donor and one particular acceptor shared a region of homology which included 8 tandem 5'-CAGU-3' repeats followed at the 3' end by a 17 nucleotide region of random homologous sequence. Derivatives of the acceptor either completely lacked the 17 nucleotide region or were progressively truncated resulting in a shorter region. With the acceptor lacking this region, prominent transfer products differing in length by 4 nucleotides were observed. Presumably this occurs because the transferring DNA can base-pair with several copies of the repeat elements of the acceptor. Addition of 5 or more of the 17 random nucleotides to the 3' end of the acceptor resulted in transfer products of essentially one length, and consistent with the transferring DNA correctly base-pairing with the 3' nucleotides. Results suggest that the transferring DNA interacts with the acceptor over several bases to form the most energetically stable hybrid duplex prior to extension on the acceptor. Hybrids formed from shorter interactions between the 3' end of the DNA and acceptor are either realinged prior to extension or precluded due to the mechanism of transfer.

Patients' experiences of Parkinson's disease

Patients' (n = 101) experiences of Parkinson's disease (PD) were studied through structured interviews. Oblique factor analysis produced three moderately intercorrelated clusters of items reflecting reported severity of motoric, cognitive, and psychological problems, respectively. Scales formed from the factors were correlated with demographic, disease-related, and psychosocial variables. The demographic variables were not significantly correlated with the scales or with any other variables in the set. Hoehn and Yahr staging was significantly related to scores only on the motoric severity scale. Measures of functional capacity, in contrast, were significantly associated with all three scales. Although the addition of the psychosocial variables as a set significantly increased multiple Rs for each of the three scales, the specific patterns of correlation varied from scale to scale. The findings indicate that from the viewpoint of the patient the problems created by PD were not restricted to the motoric domain. Too narrow a focus by clinicians and researchers on medical symptomatology may give insufficient recognition to the multidimensional nature of the patient's experience.

Effects of spectral pattern on the perceptual salience of partials in harmonic and frequency-shifted complex tones: a performance measure

A single even harmonic added to an odd-harmonic complex is often judged to be more salient than its odd neighbors in a clarity rating task [Roberts and Bregman, J. Acoust. Soc. Am. 90, 3050-3060 (1991)]. This study used similar complexes in a two-interval forced-choice procedure. Each interval consisted of a complex tone followed by a pure tone, whose frequency matched that of a harmonic in one interval but was changed by +/- 0.5 x fundamental frequency in the other. Subjects were asked to identify the matching interval. Since the pure tone followed the complex tone, it could not cue listening to a particular frequency region. The possibility of cross-interval cuing was reduced by changing the fundamental frequency between intervals (100-150 Hz range). The procedure was designed to maximize the effects on performance of differences in immediate perceptual salience between the partials. The added even harmonic was typically judged with greater accuracy than its odd neighbors (experiment 1), though this effect was greatly reduced for harmonics above 8 (experiment 2). The even-odd difference persisted when the original stimuli were made inharmonic by applying a frequency shift of 15%, but was abolished for stimuli consisting of successive partials (experiment 3).

Contamination of propofol infusions in the intensive care unit: incidence and clinical significance

Epidemics of bacteraemia and wound infection have been associated with the infusion of bacterially contaminated propofol administered during anaesthesia. We conducted an observational study to determine the incidence and clinical significance of administration of potentially contaminated propofol to patients in an ICU setting. One hundred patients received a total of 302 infusions of propofol. Eighteen episodes of possible contamination of propofol syringes were identified, but in all cases contamination was by a low-grade virulence pathogen. There were no episodes of clinical infection or colonization which could be attributed to the administration of contaminated propofol. During the routine use of propofol to provide sedation in ICU patients the risk of nosocomial infection secondary to contamination of propofol is extremely low.

Augmentative and alternative communication to support receptive and expressive communication for people with autism

In this article the authors discuss the use of augmentative and alternative communication (AAC) as used to enhance comprehension and expression of people with autism. A theoretical model for AAC assessment and intervention planning is presented. Application of the model is illustrated through a case report of a 6-year-old boy with autism who had severe expressive and receptive language impairments.

Brevetoxicosis in manatees (Trichechus manatus latirostris) from the 1996 epizootic: gross, histologic, and immunohistochemical features

In 1996, at least 149 manatees (Trichechus manatus latirostris) died in an unprecedented epizootic along the southwest coast of Florida. At about the same time, a bloom of the brevetoxin-producing dinoflagellates, Gymnodinium breve, was present in the same area. Grossly, severe nasopharyngeal, pulmonary, hepatic, renal, and cerebral congestion was present in all cases. Nasopharyngeal and pulmonary edema and hemorrhage were also seen. Consistent microscopic lesions consisted of catarrhal rhinitis, pulmonary hemorrhage and edema, multiorgan hemosiderosis, and nonsuppurative leptomeningitis. Immunohistochemical staining using a polyclonal primary antibody to brevetoxin (GAB) showed intense positive staining of lymphocytes and macrophages in the lung, liver, and secondary lymphoid tissues. Additionally, lymphocytes and macrophages associated with the inflammatory lesions of the nasal mucosa and meninges were also positive for brevetoxin. These findings implicate brevetoxicosis as a component of and the likely primary etiology for the epizootic. The data suggest that mortality resulting from brevetoxicosis may not necessarily be acute but may occur after chronic inhalation and/or ingestion. Immunohistochemical staining with interleukin-1-beta-converting enzyme showed positive staining with a cellular tropism similar to GAB. This suggests that brevetoxicosis may initiate apoptosis and/or the release of inflammatory mediators that culminate in fatal toxic shock.

Selective glial vulnerability following transient global ischemia in rat brain

Global cerebral ischemia selectively damages neurons, but its contribution to glial cell death is uncertain. Accordingly, adult male rats were sacrificed by perfusion fixation at 1, 2, 3, 5, and 14 days following 10 minutes of global ischemia. This insult produces CA1 hippocampal neuronal death at post-ischemic (PI) day 3, but minor or no damage to neurons in other regions. In situ end labeling (ISEL) and immunohistochemistry identified fragmented DNA of dead or dying glia and distinguished glial subtypes. Rare ISEL-positive oligodendroglia, astrocytes, and microglia were present in control brain. Apoptotic bodies and ISEL-positive glia significantly increased at PI day 1 in cortex and thalamus (p < 0.05), but were similar to controls in other regions and at other PI intervals. Most were oligodendroglia, although ISEL-positive microglia and astrocytes were also observed. These results show that oligodendroglia die rapidly after brief global ischemia and are more sensitive than neurons in certain brain regions. Their selective vulnerability to ischemia may be responsible for the delayed white matter damage following anoxia or CO poisoning or that associated with white matter arteriopathies. Glial apoptosis could contribute to the DNA ladders of apoptotic oligonucleosomes that have been found in post-ischemic brain.

Biopatch--a new concept in antimicrobial dressings for invasive devices

A randomised controlled trial (RCT) was conducted to assess the reduction in the rate of catheter-related infections associated with the Biopatch dressing (Johnson & Johnson Medical Inc., Arlington, Texas, USA) used for insertion-site management of central venous catheters (CVCs) placed in the intensive care unit. Patients having a CVC placed were randomly assigned to receive either a Biopatch keyhole dressing to the occlusive Opsite IV 3000 (Smith and Nephew Medical Ltd., Hull, UK) (experimental group) or the Opsite IV 3000 alone (control group). There was a very low colonisation rate of CVC tip and skin exit-site swabs in both the experimental group (6 of 17) and the control group (5 of 16). No statistical difference was found between the two groups with regard to CVC or exit-site colonisation. A calculated sample size of 11,000 would be required to statistically demonstrate a 10 per cent reduction in CVC infection rate using the new Biopatch dressing. A much larger RCT would be required to demonstrate the efficacy of this new device.

Characterisation and molecular typing of Burkholderia pseudomallei: are disease presentations of melioidosis clonally related?

Eighteen cases of culture positive melioidosis caused by Burkholderia pseudomallei, were seen in four geographically separate communities in North Queensland, Australia. The genetic inter-relatedness of the clinical isolates were compared utilising random amplification of polymorphic DNA (RAPD) and multilocus enzyme electrophoresis (MEE). The isolates segregated into two groups that correlated with clinical presentation rather than geographical location. This is the first described association between the varied clinical presentations of this condition and specific molecular type. If proven on larger studies, this may further our understanding of the pathogenesis of this important condition.

Development of safe and efficient retroviral vectors for Gaucher disease

We have generated amphotropic and Gibbon ape leukemia (GaLV) viruses carrying either a full-length (IG-GC2) or a shortened glucocerebrosidase cDNA (IG-GC4). For all recombinant retroviruses, a single infection was sufficient to augment glucocerebrosidase activity in unselected Gaucher type I and type II fibroblasts to levels which can be considered therapeutic. Transfer efficiency of the glucocerebrosidase cDNA into normal human and Gaucher type I CD34+ cells, using supernatant transduction, ranged from 4 to 50% as established on vector-positive CFU-GM. In these experiments, GaLV and amphotropic virus were equally efficient in transducing early human progenitors. Importantly, mixing amphotropic and GaLV pseudotyped retroviruses resulted in significantly higher transduction efficiencies as compared with single infections, up to 70% vector-positive CFU-GM. Glucocerebrosidase activity, measured in the progeny of human CD34+ cells, increased up to 460% compared with mock-infected CD34+ cells. Upon transduction of Gaucher CD34+ bone marrow cells the glucocerebrosidase deficiency was reversed.

Recombinant soluble interleukin-11 (IL-11) receptor alpha-chain can act as an IL-11 antagonist

We have expressed a soluble N-glycosylated form of the murine interleukin-11 (IL-11) receptor alpha-chain (sIL-11R) and examined signaling in cells expressing the gp130 molecule. In the presence of gp130 but not the transmembrane IL-11R, the sIL-11R mediated IL-11-dependent differentiation of M1 leukemic cells and proliferation in Ba/F3 cells. Early intracellular events stimulated by the sIL-11R including phosphorylation of gp130, STAT 3, and SHP-2 were similar to signaling through the transmembrane IL-11R. IL-11 bound to sIL-11R with low affinity (kd 10 to 50 nmol/L). Binding of sIL-11R to gp130 was IL-11 dependent with intermediate affinity (kd 1.5 to 3.0 nmol/L). However, the concentration of IL-11 required for signaling through the sIL-11R was 10- to 20-fold greater than that required for cells expressing the transmembrane IL-11R and gp130 in the absence of sIL-11R. Furthermore, the sIL-11R was capable of antagonizing the activity of IL-11 when tested on cells expressing the transmembrane IL-11R and gp130. We propose that the observed IL-11 antagonism by the sIL-11R may depend on limiting numbers of gp130 molecules on cells already expressing the transmembrane IL-11R.

A family of bicistronic vectors to enhance both local and systemic antitumor effects of HSVtk or cytokine expression in a murine melanoma model

The herpes simplex virus-thymidine kinase/ganciclovir (HSVtk/GCV) system produces both direct and immune-mediated tumor cell killing. Here, we compare the efficacy of HSVtk/GCV with cytokines, alone and in combination, on the tumorigenicity and immunogenicity of B16 cells. With respect to single gene modifications, only HSVtk/GCV, or high-level interleukin-2 (IL-2) secretion, completely prevented tumor growth, whereas granulocyte-macrophage colony-stimulating factor (GM-CSF) generated the best levels of long-term systemic protection. To augment both local killing and immune activation, we constructed bicistronic constructs that express HSVtk and a cytokine within the same cell. Co-expression of HSVtk with IL-2 or GM-CSF enhanced the local antitumor activity of any gene alone. In a tumor-prevention model, HSVtk killing, in an environment preprimed with GM-CSF, generated the best long-term immune protection. However, in a short-term therapy model, continued IL-2 expression was most effective against 3-day established tumors. This probably reflects differences in the activities of IL-2 and GM-CSF in generating short-term, nonspecific immune stimulation compared to long-term immunological memory, respectively. As a prelude to in vivo delivery experiments, we also demonstrated that these bicistronic cassettes can be packaged normally into retroviral (5 x 10(5) virus/ml from pooled populations) and adenoviral vectors (5 x 10(9) virus/ml) and function as predicted within virally infected cells. This family of bicistronic vectors can be used to stimulate synergy between suicide and cytokine genes, overcomes the problems of delivering two genes on separate vectors, and should allow easier preparation of vectors for the delivery of multiple genes to patients' tumor cells.

Clinically relevant suramin dosing regimen in mice with no effects against PC-3 prostate xenografts

The goal of these studies was to develop a suramin dosing schedule that would maintain suramin plasma concentrations in mice in the 150-250 mu g/ml range. A high pressure liquid chromatography method was used to determine suramin plasma concentrations in mice. For pharmacokinetic studies CD2F(1) mice were treated intraperitoneally with 140 mg/kg of suramin. These pharmacokinetic data were used to develop a clinically relevant dosing regimen. To test the efficacy of this dosing regimen, athymic nude mice were implanted orthotopically with PC-3 prostate carcinoma cells, randomized, and treated intraperitoneally. The pharmacokinetically derived dosing regimen resulted in no antitumor effect against PC-3 prostate tumors. Suramin plasma concentrations ranged from 155 to 258 mu g/ml over the 14-day therapy period with tumor concentrations in the 53-241 mu g/g wet weight range.