Transceive surface coil array for MRI of the human prostate at 4T.

A novel torso transceive surface coil array for prostate magnetic resonance imaging (MRI) and spectroscopy (MRS) at 4T is presented. It is shown that with the use of a conformal transceive surface coil array with 50 Omega transmitter amplifiers and receiver preamplifiers, one can perform whole-volume torso imaging while maintaining the high signal-to-noise ratio (SNR) inherent to surface coil designs. Recent theoretical considerations have shown that by focusing the infringing radiofrequency (RF) electromagnetic field, one can achieve increased penetration and signal homogeneity compared to a conventional circularly polarized driving scheme. A variation of this driving scheme particular to the proposed coil design resulted in a twofold increase in SNR in the prostate compared to that achieved with a conventional circularly polarized driving scheme. The novel transceive surface coil array presented is capable of full-volume imaging of the human torso at 4T while maintaining signal penetration in the deep region of the prostate gland.     

Characterization of the immunological memory state generated in mice susceptible to Leishmania major following exposure to low doses of L. major and resulting in resistance to a normally pathogenic challenge

BALB/c mice are susceptible to a high-dose infection of the protozoan Leishmania major, which induces a parasite-specific antibody, Th2-like response, exclusive of a significant and protective cell-mediated Th1 component. We have shown, in contrast, that infection with a low number of parasites induces cell-mediated immunity exclusive of antibody production, and results in resistance to substantial subsequent high-dose infection. Low-dose exposure thus constitutes effective vaccination. In the present study, we analyze lymphokine production by parasite-specific T cells from these low-dose exposed, resistant mice and from normal, susceptible mice following high-dose infection. Two findings stand out. First, the parasite-specific T cells in mice rendered resistant appear not to be in an activated, effector state at the time of parasite challenge, as assessed by lack of lymphokine production on short-term stimulation with parasite antigens, but to be rather in a memory state. Second, the ratio of parasite antigen-dependent production of interferon-γ to that of interleukin-4 by spleen cells of low-dose exposed and normal mice upon high-dose challenge takes a dramatically different course. This ratio is similar in both groups of mice shortly after challenge, but increases dramatically in the resistant and declines dramatically in the control mice over a period of weeks, such that these ratios differ by about 60-fold 12 weeks after the high-dose challenge. In addition, we show that a similar state of resistance occurs following low-dose infection with a more virulent strain of L. major. In toto, our observations suggest that resistance may be generally achievable by low-dose exposure and may be associated with a memory state which, when activated by parasite challenge, results in the evolution of the response over weeks such that the protective, Th1 component becomes ever more dominant over the Th2 component.     

Image-directed percutaneous biopsies with a biopsy gun

Core tissue for histologic study is believed by many pathologists to be more diagnostic than material from needle aspiration. Recently, a biopsy "gun" has been introduced, which simplifies core biopsies. With this device, 182 biopsies of multiple anatomic sites were performed with ultrasonic, computed tomographic, and fluoroscopic guidance and 18-gauge needles. High-quality histopathologic specimens were obtained in 177 of the biopsies, and diagnostic target tissue was obtained in 167. Only three significant complications occurred: one bleeding complication that required transfusion and two cases of pneumothorax that necessitated placement of chest tubes. The biopsy gun eliminated the disjointed movements of conventional "skinny" needle biopsies, and none of the samples demonstrated significant "crush" artifact or obscuring blood, problems that are commonly associated with manual biopsy techniques. Patient discomfort was decreased with this system compared with that of manual biopsies, and the total procedure time was reduced. Because of these distinct advantages, the authors now use the biopsy gun exclusively for all percutaneous biopsies and recommend that other institutions consider the use of this biopsy method.     

Isolation, distribution and prevalence of various species of enterococci isolated from clinical specimens in a tertiary care hospital

Various clinical specimens were processed to find the prevalence rate of enterococci and to identify the species of clinical isolates of enterococci. Screening of various clinical specimens revealed that enterococci were prevalent in 2% of the total specimens, with urine and wound to be the major site of isolation. Conventional test scheme proposed by Facklam and Collins and commercially available systems Rapid ID 32 Strep (biomereiux) were successfully used to speciate enterococcal strains. Five species of enterococci were identified in the study from a set of 396 cultures, with E. faecalis (79.79%), and E. faecium (11.11%) predominating. E. hirae (3.03%), E. gallinarum (3.03%), and E. casseliflavus (3.03%), were the other members of Enterococcus species identified.     

Interleukin 10 protects mice against staphylococcal enterotoxin B-induced lethal shock.

We investigated the ability of interleukin 10 (IL-10) to protect mice against lethal shock induced by staphylococcal enterotoxin B (SEB). Treatment of mice with IL-10 prevented the death of mice injected with SEB in a dose-dependent manner. IL-10-mediated protection was apparent when administered either prior to or concurrent with SEB but was less effective when administered following SEB injection. This observation indicates that IL-10 is capable of regulating T-cell activation in vivo.