Comparison of PCR and pp65 antigenemia assay with quantitative shell vial culture for detection of cytomegalovirus in blood leukocytes from solid-organ transplant recipients

This study compared PCR and an assay for cytomegalovirus (CMV) pp65 antigenemia (CMV-vue; INCSTAR Corp.) with a quantitative shell vial culture (QSVC) technique for the detection of CMV in serial blood specimens from 46 solid-organ transplant recipients. In a comparison based on 535 specimens tested by PCR and QSVC, CMV was detected by PCR in 41 and by QSVC in 37 of 43 recipients at risk of CMV infection. The mean number of days after transplantation of initial detection of CMV was 29.9 for PCR and 34.0 for QSVC (P = 0.01). The antigenemia assay was performed on 395 specimens, including 304 of those also tested by PCR. In these specimens, CMV was detected by the antigenemia assay, QSVC, and PCR in 30, 32, and 35 (respectively) of 38 patients at risk, with no statistically significant difference in the time to detection. Each of the assays detected CMV in similar proportions of patients with and without clinically significant CMV infection. PCR stayed positive longer after transplantation than the other assays but frequently returned to negative when more than 6 months had elapsed after transplantation. The antigenemia assay and PCR stayed positive longer after institution of antiviral therapy than QSVC. PCR can provide highly sensitive detection of CMV viremia, but a PCR assay for CMV is not yet available in kit form. The pp65 antigenemia assay and shell vial culture are quantifiable and comparable in sensitivity. Either is recommended for rapid detection of CMV in blood specimens from solid-organ transplant recipients.     

Genetic determinants of p53-induced apoptosis and growth arrest

Previous studies have suggested that expression of p53 in cancer cells can result in either growth arrest or apoptosis. Accordingly, expression of p53 in a series of colorectal cancer cell lines yielded growth arrest in some lines (A-lines) and apoptosis in others (D-lines). To investigate the basis of this difference, we evaluated the role of p21WAF1/Cip1, a known mediator of p53-induced growth arrest. Inactivation of p21 by homologous recombination converted an A-line to a D-line, suggesting that p21 could protect cells from apoptosis. However, examination of p53-induced p21 expression in naturally occurring D-lines and A-lines demonstrated that the induction of p21 could not account for the differential response to p53. Moreover, when a D-line was fused to an A-line, the resulting hybrid cells underwent apoptosis in response to p53, indicating that the apoptosis pathway was dominant over the growth arrest pathway. Therefore, the apoptotic response to p53 in colorectal cancer cells is modulated by at least two factors: p21-mediated growth arrest that can protect cells from apoptosis in A-cells, and trans-acting factors in D-cells that can overcome this protection, resulting in cell death.     

The yeast spindle pole body component Spc72p interacts with Stu2p and is required for proper microtubule assembly

We have previously shown that Stu2p is a microtubule-binding protein and a component of the Saccharomyces cerevisiae spindle pole body (SPB). Here we report the identification of Spc72p, a protein that interacts with Stu2p. Stu2p and Spc72p associate in the two-hybrid system and can be coimmunoprecipitated from yeast extracts. Stu2p and Spc72p also interact with themselves, suggesting the possibility of a multimeric Stu2p-Spc72p complex. Spc72p is an essential component of the SPB and is able to associate with a preexisting SPB, indicating that there is a dynamic exchange between soluble and SPB forms of Spc72p. Unlike Stu2p, Spc72p does not bind microtubules in vitro, and was not observed to localize along microtubules in vivo. A temperature-sensitive spc72 mutation causes defects in SPB morphology. In addition, most spc72 mutant cells lack cytoplasmic microtubules; the few cytoplasmic microtubules that are observed are excessively long, and some of these are unattached to the SPB. spc72 cells are able to duplicate and separate their SPBs to form a bipolar spindle, but spindle elongation and chromosome segregation rarely occur. The chromosome segregation block does not arrest the cell cycle; instead, spc72 cells undergo cytokinesis, producing aploid cells and polyploid cells that contain multiple SPBs.     

Stiffness of trabecular bone of the tibial plateau in patients with rheumatoid arthritis of the knee

Stiffness of subchondral proximal tibial trabecular bone is a factor in the stability of prostheses implanted into that bone. The stiffness of trabecular bone in osteoarthritis (OA) has been documented. Trabecular bone in rheumatoid arthritis (RA) is osteopenic in numerous sites and morphologically abnormal in the proximal tibia. Reliable data on proximal tibial bone in RA are lacking, although 1 study failed to identify abnormalities. The purposes of this study were (1) to document the stiffness of the proximal tibial cancellous bone in patients with RA, (2) to determine the effect of angular deformity on bone stiffness in rheumatoid patients, and (3) to compare RA stiffness values with those in published reports for OA. Fifteen tibial plateau were obtained from patients with RA during surgery. Each plateau was horizontally seated in a mold and covered with cement. The plateau was divided into 6 regions, which were used to facilitate comparison between specimens and the existing literature. Indentation tests were conducted with a 4-mm-diameter cylindrical indentor controlled by an MTS machine. The indentor descended at a rate of 2 mm/min to a maximum depth of 1.0 mm; load and displacement data were digitally recorded. Stiffness was calculated from the slope of the linear region of the curve using best-fit linear regression. Where varus deformity was present, stiffness in the medial plateau was higher overall than for the other compartment; whereas in the case of valgus deformity, stiffness of the lateral side was significantly higher (P < .05 for each observation). In comparison to older normal specimens, both the medial compartment of the varus RA specimens (P < .01) and the posterolateral compartment of the valgus RA specimens (P < .01) had significantly lower stiffness. Comparison with OA specimens showed that in varus RA, the posteromedial region had significantly lower stiffness than in varus OA at the same site (P < .01). In valgus RA, the lateral region had significantly lower stiffness than in valgus OA at the same site (P < .01). The mean stiffness ratio of the valgus RA was significantly (P < .01) altered from normal, and for the varus RA, it was significantly (P < .01) different from normal posteriorly. The stiffness ratios for the varus RA were significantly (P < .01) different from those for varus OA; there was no difference between valgus RA and valgus OA. It is concluded that RA affected bone has significantly lower stiffness than normal and osteoarthritic bone. The loaded plateau is stiffer than the unloaded plateau in angular deformity, but is still less stiff than normal bone and osteoarthritic plateaus with corresponding deformities.     

Hemodynamic characteristics, myocardial kinetics and microvascular rheology of FS-069, a second-generation echocardiographic contrast agent capable of producing myocardial opacification from a venous injection

OBJECTIVES: We sought to 1) study the effects of FS-069 on cardiac and systemic hemodynamic function, myocardial blood flow, left ventricular wall thickening and pulmonary gas exchange when injected intravenously; and 2) compare the myocardial kinetics and microvascular rheology of FS-069 and Albunex when injected directly into a coronary artery. BACKGROUND: FS-069 is a second-generation echocardiographic contrast agent composed of perfluoropropane-filled albumin microspheres; it is capable of consistent and reproducible myocardial opacification from a venous injection. METHODS: Nine dogs were used to study the effects of FS-069 on hemodynamic function, pulmonary gas exchange, left ventricular wall thickening and myocardial blood flow and to characterize its myocardial kinetics when injected intravenously. These dogs were also used to compare the myocardial kinetics of FS-069 with those of Albunex during intracoronary injections. Nine Sprague-Dawley rats were used to compare the microvascular rheology of these two contrast agents, and in vitro modeling was performed to assess whether the microvascular findings of FS-069 can explain its echocardiographic behavior during direct coronary injections. RESULTS: There were no effects of 30 rapid venous injections of FS-069 (every 20 s) on cardiac output; mean aortic, pulmonary or left atrial pressures; and peak positive and negative first derivative of left ventricular pressure (dP/dt). Similarly, there were no effects of this agent on radiolabeled microsphere-measured regional myocardial blood flow, left ventricular wall thickening or pulmonary gas exchange. When injected intravenously, the myocardial transit of this agent resembled a gamma-variate form. When diluted FS-069 was injected directly into the coronary artery; however, its transit resembled the integral of gamma-variate function, with persistent myocardial opacification lasting several minutes, which was different from that of Albunex. Intravital microscopy revealed that, unlike Albunex, when no bubbles are entrapped within the microcirculation after an arterial injection, a very small fraction of the diluted, larger FS-069 microbubbles are entrapped. In vitro modeling confirmed that this small fraction of microbubbles can result in persistent myocardial opacification. CONCLUSIONS: FS-069 produces no changes in hemodynamic function, myocardial blood flow, left ventricular wall thickening or pulmonary gas exchange when injected intravenously in large amounts. When diluted FS-069 is injected into the coronary artery, a very small fraction of the larger bubbles are entrapped within the microcirculation, resulting in a persistent contrast effect. Thus, although FS-069 is a safe intravenous echocardiographic contrast agent, it cannot provide information on myocardial blood flow when injected directly into a coronary artery.     

Autoradiographic assessment of blood flow heterogeneity in the hamster heart

OBJECTIVE: Provide regional flow measurement in the hearts of small mammals using a new, higher-resolution technique based on the deposition of a molecular marker. METHODS: We determined the instantaneous extraction and retention of the "molecular microsphere" radiolabeled desmethylimipramine in retrogradely perfused hamster hearts. In a separate series of experiments, autoradiography was used to measure regional myocardial deposition densities in hamster hearts of about 0.5 g with spatial area resolution of 16 x 16 microns. RESULTS: Radiolabeled desmethylimipramine is almost 100% extracted during a single transcapillary passage and is retained in the tissue for many minutes. Autoradiographic images demonstrated a spatial flow heterogeneity with standard deviations of 31 +/- 4% of the mean flow (N = 5) in 16 x 16 x 20-micronm3 voxels. This is equivalent to the projections made using fractal relationships from cruder observations obtained with microspheres in the hearts of baboons, sheep, and rabbits. CONCLUSIONS: Autoradiography using a molecular deposition marker provides quantitative information on myocardial flow heterogeneities with resolution at the size of cardiac myocytes. Because the regions resolved are smaller than the volume of regions supplied by single arterioles, the results must slightly exaggerate the true heterogeneity of regional flows.     

Differences in detection of alcohol use in a prenatal population (on a Northern Plains Indian Reservation) using various methods of ascertainment

Although Fetal Alcohol Syndrome (FAS) rates have been reported to be higher in American Indian populations, no screening tool has been validated for alcohol use in American Indian women. The objectives of this study were to compare the detection of prenatal alcohol use by a self-administered questionnaire to detection by clinical interview; and to ascertain whether the screening tool would increase detection of pregnant women who are abusing alcohol. The hospital records of the women were reviewed for any history of alcohol-related illnesses or injuries to compare with results obtained from the questionnaire. Seventy women attending their first prenatal clinic visit on a reservation were screened for alcohol use. There was a wide range in detection of prenatal alcohol use (20%-71% of the sample detected) depending on the method used. There was a large variation in sensitivities (7%-93%) of the individual questions in identifying patients detected as "high risk" by the clinicians. The T-ACE screening questions significantly increased detection of alcohol use compared to detection by the clinicians (p = 0.04 Fisher's exact test). Due to the large variation between different methods of detection, it is recommended that screening tools that increase detection of alcohol use should be combined with methods of higher specificity such as using questions about quantity and frequency of alcohol intake, medical chart review and clinical interview. We also found that various interpretations of the screening questions by the patients highlighted the need to tailor the wording of individual questions to the particular patient population.     

Effect of post-slaughter processing and freezing on the functionality of hot-boned meat from young bull

The effects of variation in the times of mincing post mortem (2, 4, or 6 h), pre-rigor salting (1.5% wt wt ) and freezing rate [fast (10 min, liquid nitrogen); medium (4-6 h at -40 °C and 0.8 m s(-1) air velocity); or slow (36-38 h at -10 °C and 0.1 m s(-1) air velocity followed by 12 h at -20 °C and 0.1 m s(-1) air velocity)] on the functionality of young bull meat were examined using hot-boned forequarters. At 52 h post packaging, the meat was thawed (72 h at 4 °C), its pH measured, and it was used to make finely comminuted batters. Cook yield and stress and strain of the cooked batters were measured. Time of mincing had no effect on meat pH, cook yield or stress and strain. There was a significant interaction (P < 0.05) between pre-rigor salting and freezing rate for pH. Freezing rate did not affect the pH of pre-rigor salted meat whereas the pH of unsalted pre-rigor meat was highest at the fastest freezing rate. Meat salted pre-rigor had a significantly (P < 0.05) higher pH than the post-rigor chilled control. Pre-rigor salting decreased the stress values of cooked batter whereas the slowest freezing rate increased stress. Stress and strain values for cooked batters from thawed meat were not significantly different from the values for batters made from the unfrozen control. Cook yields of batters made from pre-rigor frozen meat were higher than that of the postrigor control but not significantly so. The results indicate that suppliers can use pre-rigor salted and frozen meat when manufacturing comminuted products without major detrimental effects on the cook yield and texture of the finished product.     

On the quantum and randomized approximation of linear functionals on function spaces

We deal with quantum and randomized algorithms for approximating a class of linear continuous functionals. The functionals are defined on a H?lder space of functions f of d variables with r continuous partial derivatives, the rth derivative being a H?lder function with exponent ρ. For a certain class of such linear problems (which includes the integration problem), we define algorithms based on partitioning the domain of f into a large number of small subdomains, and making use of the well-known quantum or randomized algorithms for summation of real numbers. For N information evaluations (quantum queries in the quantum setting), we show upper bounds on the error of order N ^−(γ+1) in the quantum setting, and N ^−(γ+1/2) in the randomized setting, where γ = (r + ρ)/d is the regularity parameter. Hence, we obtain for a wider class of linear problems the same upper bounds as those known for the integration problem. We give examples of functionals satisfying the assumptions, among which we discuss functionals defined on the solution of Fredholm integral equations of the second kind, with complete information about the kernel. We also provide lower bounds, showing in some cases sharpness of the obtained results, and compare the power of quantum, randomized and deterministic algorithms for the exemplary problems.