Improved CD4 lymphocyte outgrowth in response to effective antiretroviral therapy

PURPOSE: Embolism is believed to be the major cause of end-organ damage after angioplasty and endoluminal procedures. Recently, Doppler ultrasound scanning has been used to detect asymptomatic cerebral emboli. We determined whether asymptomatic embolic signals (ES) could be detected distal to a significant iliac artery stenosis of >60% both before and soon after iliac percutaneous transluminal angioplasty (PTA). METHODS: A 2-MHz Doppler scan probe was used to monitor for ES in the common femoral artery before and after 10 successful iliac artery PTAs and at various standardized times in the following 24 hours. The same protocol was used to study 10 patients in the control group after renal PTA. In addition, a single recording was performed in a second nonoperative control group of 10 patients who had no evidence of peripheral vascular disease. The Doppler scan signals were recorded on tape for a later blinded analysis. RESULTS: In the 24 hours before iliac PTA, asymptomatic ES were detected in four of 10 patients during a 1-hour recording but in no controls (P =.025). After iliac PTA, ES were detected at 30 minutes in nine of 10 iliac subjects but in only one of 10 renal subjects (P =.0003) and at 2 hours in eight of 10 iliac subjects but in only one of 10 renal subjects (P =.001). The occurrence of ES became less frequent, and ES were present at a lower frequency in eight of 10 iliac PTA subjects at 4 hours and in five of 10 at 24 hours but in no renal PTA subjects at these time points. CONCLUSIONS: ES can be detected in the common femoral artery with Doppler ultrasound scanning in patients with iliac artery stenosis both before and soon after iliac PTA despite preangioplasty aspirin and intra-angioplasty heparin therapies. The occurrences of ES were particularly frequent in the 2 hours after PTA. This technique can be used further to study factors that control plaque stability and to evaluate the effect of therapeutic interventions.     

The use of the flow-volume loop in assessing the results of laryngotracheal reconstruction

Wild fungal strains isolated from litter and soil were inoculated in test tubes containing a synthetic medium with 0.5% sodium carboxymethylcellulose (CMC) as sole carbon source. After the incubation time, cylindrical probes were taken from each tube using a borer and stained with Congo red 0.1% to reveal the remaining CMC. The relative cellulase activity was estimated by measuring the deepness of the clearing zone, and the growth by the limit of mycelial penetration in the medium. The ratio: hydrolysis zone/depth of growth, provides additional information to compare strains. A test using culture supernatants of liquid media growing strains was developed for enzyme assay using a modification of the cylinder-plate method. Petri dishes were filled with agar-CMC medium and cups were cut off with a steel punch. Such cups were filled with culture supernatants. After incubation, the plated were stained with Congo red, and the diameter of each cleared zone was recorded. Comparative studies of strains could be performed as well as quantitation of enzyme activity using a standard cellulase solution and computing the area of the cleared zones. This method may be useful when a large number of strains must be tested for cellulolytic activity or when conventional tests fail for assaying enzymatic induction in vitro.     

Transcutaneous interruption of ultrasound contrast agents for blood flow evaluation

RATIONALE AND OBJECTIVES: The ability to create short boluses in targeted arteries with rapid rise times is limited by the transport of bubbles from the venous to arterial portion of the circulation. Acoustic interruption of contrast agent in arteries may create the short boluses necessary for simple wash-in/wash-out measures of blood flow. METHODS: An ultrasound contrast agent was used with spectral Doppler ultrasound to observe contrast interruption in femoral arteries and VX2 carcinoma in a rabbit model. At an upstream location in the femoral artery, single, sinusoidal ultrasound tone bursts at 1.8 MHz with durations of 0.25 to 1 seconds were applied to interrupt the flow of contrast agent injected intravenously. RESULTS: In VX2 carcinoma, bursts as short as 40 cycles produced contrast interruption lasting only one cardiac cycle within the tumor periphery and I(SPPA) <3 W/cm2 produced measurable interruptions. CONCLUSIONS: Acoustic fields applied transcutaneously interrupted flow of contrast agents to form temporally short negative boluses.     

Perforin is essential for control of ectromelia virus but not related poxviruses in mice

Lack of perforin renders the relatively resistant mouse strain C57BL/6 highly susceptible to the natural mouse pathogen ectromelia virus, a cytopathic orthopoxvirus. This is indicated by increased mortality, elevated virus titers and pathology in liver and spleen, and increased levels of liver enzymes in blood. Cowpox virus on the other hand is more virulent in the presence of perforin than in its absence. An additional lack of granzyme A which together with perforin is a constituent of cytoplasmic granules from cytotoxic T cells increases the virulence of cowpox virus.     

Caveolin interacts with Trk A and p75(NTR) and regulates neurotrophin signaling pathways

Neurotrophins signal through Trk tyrosine kinase receptors and the low-affinity neurotrophin receptor p75(NTR). We have shown previously that activation of Trk A tyrosine kinase activity can inhibit p75(NTR)-dependent sphingomyelin hydrolysis, that caveolae are a localized site for p75(NTR) signaling, and that caveolin can directly interact with p75(NTR). The ability of caveolin to also interact with tyrosine kinase receptors and inhibit their activity led us to hypothesize that caveolin expression may modulate interactions between neurotrophin signaling pathways. PC12 cells were transfected with caveolin that was expressed efficiently and targeted to the appropriate membrane domains. Upon exposure to nerve growth factor (NGF), caveolin-PC12 cells were unable to develop extensive neuritic processes. Caveolin expression in PC12 cells was found to diminish the magnitude and duration of Trk A activation in vivo. This inhibition may be due to a direct interaction of caveolin with Trk A, because Trk A co-immunoprecipitated with caveolin from Cav-Trk A-PC12 cells, and a glutathione S-transferase-caveolin fusion protein bound to Trk A and inhibited NGF-induced autophosphorylation in vitro. Furthermore, the in vivo kinetics of the inhibition of Trk A tyrosine kinase activity by caveolin expression correlated with an increased ability of NGF to induce sphingomyelin hydrolysis through p75(NTR). In summary, our results suggest that the interaction of caveolin with neurotrophin receptors may have functional consequences in regulating signaling through p75(NTR) and Trk A in neuronal and glial cell populations.     

Effect of Lactobacillus acidophilus strain NP51 on Escherichia coil O157:H7 fecal shedding and finishing performance in beef feedlot cattle

A 2-year study was conducted during the summer months (May to September) to test the effectiveness of feeding Lactobacillus acidophilus strain NP51 on the proportion of cattle shedding Escherichia coli O157:H7 in the feces and evaluate the effect of the treatment on finishing performance. Steers (n = 448) were assigned randomly to pens, and pens of cattle were assigned randomly to NP51 supplementation or no supplementation (control). NP51 products were mixed with water and applied as the feed was mixed daily in treatment-designated trucks at the rate of 10(9) CFU per steer. Fecal samples were collected (n = 3,360) from the rectum from each animal every 3 weeks, and E. coli O157:H7 was isolated by standard procedures, using selective enrichment, immunomagnetic separation, and PCR confirmation. The outcome variable was the recovery of E. coli O157:H7 from feces, and was modeled using logistic regression accounting for year, repeated measures of pens of cattle, and block. No significant differences were detected for gain, intakes, or feed efficiency of control or NP51-fed steers. The probability for cattle to shed E. coli O157:H7 varied significantly between 2002 and 2003 (P = 0.004). In 2002 and 2003, the probability for NP51-treated steers to shed E. coli O157:H7 over the test periods was 13 and 21%, respectively, compared with 21 and 28% among controls. Over the 2 years, NP51-treated steers were 35% less likely to shed E. coli O157: H7 than were steers in untreated pens (odds ratio = 0.58, P = 0.008). This study is consistent with previous reports that feeding NP51 is effective in reducing E. coli O157:H7 fecal shedding in feedlot cattle.     

Phonon Raman spectra of colloidal CdTe nanocrystals: effect of size,non-stoichiometry and ligand exchange

Resonant Raman study reveals the noticeable effect of the ligand exchange on the nanocrystal (NC) surface onto the phonon spectra of colloidal CdTe NC of different size and composition. The oleic acid ligand exchange for pyridine ones was found to change noticeably the position and width of the longitudinal optical (LO) phonon mode, as well as its intensity ratio to overtones. The broad shoulder above the LO peak frequency was enhanced and sharpened after pyridine treatment, as well as with decreasing NC size. The low-frequency mode around 100 cm^-1 which is commonly related with the disorder-activated acoustical phonons appears in smaller NCs but is not enhanced after pyridine treatment. Surprisingly, the feature at low-frequency shoulder of the LO peak, commonly assigned to the surface optical phonon mode, was not sensitive to ligand exchange and concomitant close packing of the NCs. An increased structural disorder on the NC surface, strain and modified electron-phonon coupling is discussed as the possible reason of the observed changes in the phonon spectrum of ligand-exchanged CdTe NCs.     

Breastfeeding and shorter hospital stays

Contingent negative variation (CNV) was examined in 14 epileptic patients (5 with generalized and 9 with partial fits) both before and after 24 hours of sleep deprivation. Background CNV indices differed significantly by higher amplitudes of nearly all CNV components from the ones of healthy individuals. Amplitudes of postimperative negative waves (PINW) and general waves differed most of all. After sleep deprivation there was an PINW increase as well as the tendency to the late CNV component amplitude's increase. Elevation of CNV amplitudes after sleep deprivation was more pronounced in patients in which the deprivation provoked development of epileptic fits in comparison with patients which endured sleep deprivation rather favourably. The changes revealed in CNV components of the patients with epilepsy were considered in terms of disorders in regulatory mechanisms at the level of apical dendrites of cortical neurons' excitation.     

Use of recombinant human erythropoietin for management of anemia in dogs and cats with renal failure

Green fluorescent protein (GFP) from Aequorea victoria has rapidly become a standard reporter in many biological systems. However, the use of GFP in higher plants has been limited by aberrant splicing of the corresponding mRNA and by protein insolubility. It has been shown that GFP can be expressed in Arabidopsis thaliana after altering the codon usage in the region that is incorrectly spliced, but the fluorescence signal is weak, possibly due to aggregation of the encoded protein. Through site-directed mutagenesis, we have generated a more soluble version of the codon-modified GFP called soluble-modified GFP (smGFP). The excitation and emission spectra for this protein are nearly identical to wild-type GFP. When introduced into A. thaliana, greater fluorescence was observed compared to the codon-modified GFP, implying that smGFP is 'brighter' because more of it is present in a soluble and functional form. Using the smGFP template, two spectral variants were created, a soluble-modified red-shifted GFP (smRS-GFP) and a soluble-modified blue-fluorescent protein (smBFP). The increased fluorescence output of smGFP will further the use of this reporter in higher plants. In addition, the distinct spectral characters of smRS-GFP and smBFP should allow for dual monitoring of gene expression, protein localization, and detection of in vivo protein-protein interactions.