Choroidal hemangioma: MR findings and differentiation from uveal melanoma

Transgenic mice (T26) bearing the envelope, regulatory, and accessory genes of HIV- I develop renal disease resembling human HIV-associated nephropathy (HIVAN). Effects of vehicle (VEH) and the angiotensin-converting enzyme inhibitor captopril (CAP) were examined in wild-type (WT) or T26 mice treated from 7 to 100 d of age. Mortality was lower in CAP T26 mice (30 mg/kg: 8%; 100 mg/kg: 12%) than VEH T26 mice (52%). The urinary protein/creatinine ratio was increased in VEH T26 mice (19.5+/-7.60) versus WT mice (6.1+/-0.83), but not in low-dose (7.3+/-0.94) or high-dose (8.2+/-1.02) CAP T26 mice. Blood urea nitrogen was higher in VEH T26 mice (52+/-16.2 mg/dl) than VEH WT mice (24+/-0.8). Blood urea nitrogen was also elevated in CAP WT (high dose: 43+/-2.1 mg/dl) and T26 mice (high dose: 42+/-2.4 mg/dl). Glomerular injury was higher in VEH T26 mice (6.8+/-0.58) than VEH WT mice (0.2+/-0.08) or CAP T26 mice (low dose: 1.1+/-0.17; high dose: 0.7+/-0.13). Tubulointerstitial injury was also greater in VEH T26 mice (1.1+/-0.10) than VEH WT mice (0.2+/-0.08) or CAP T26 mice (low dose: 0.4+/-0.10; high dose: 0.3+/-0.10). These data validate recent nonrandomized studies of captopril in HIV-infected patients, and suggest that an angiotensin-converting enzyme substrate is an important mediator in HIVAN. A randomized placebo-controlled trial of captopril in HIVAN may be warranted.     

B-cell epitopes recognized by IgE from patients sensitive to Amb a 5

BACKGROUND: The response to allergens characterized by IgE-mediated hypersensitivity is selective. The search for the inherited contribution to atopy has among other things, focused on the linkage of sensitivity to the presence of specific alleles in the DR and DQ locus. More than 90% of the responders to Amb a 5, an allergen from ambrosia artemisifolia, are DR-2 positive. This relationship is logically linked to the T-cell epitope presentation by the HLA complex. OBJECTIVES: This study aims to investigate a possible relationship between T-cell epitopes, B-cell epitopes and the alleles of the DR and DQ loci in Amb a 5 sensitive DR-2+ and DR-2- individuals. METHODS: Inhibition of solid state Elisa assays by IgE-enriched and IgG-depleted, heated sera. The inhibition was carried out in checkerboard pattern, bidirectionally; A inhibits B and B inhibits A. RESULTS: The B-cell epitopes defined by the inhibition pattern were all found to be conformational. Three different epitope patterns (A, B, C) were recognized. The IgE and IgG complexes were found in only one responder. The DR and DQ locus alleles were all sequenced. Although all the individuals studied responding to Amb a 5 show presence of alleles such as 1501, associated with DR-2, our data indicates no correlation between the B-cell epitopes recognized and the DR and DQ locus alleles. A well known, general T-cell motif was recognized in the known sequence of Amb a 5. CONCLUSIONS: Our investigation suggests that the choice of B-cell recognition is regulated independently of a putative link between T-cell epitope recognition and the D locus.     

Progesterone stimulates the activity of the promoters of peripheral myelin protein-22 and protein zero genes in Schwann cells

To understand better the mechanisms by which progesterone (PROG) promotes myelination in the PNS, cultured rat Schwann cells were transiently transfected with reporter constructs in which luciferase expression was controlled by the promoter region of either the peripheral myelin protein-22 (PMP22) or the protein zero (P0) genes. PROG stimulated the P0 promoter and promoter 1, but not promoter 2, of PMP22. The effect of PROG was specific, as estradiol and testosterone only weakly activated promoters. Dose-response curves for stimulation of both promoter constructs by PROG were biphasic. RU486, a PROG antagonist, did not abolish the effect of PROG, but stimulated promoter activities by itself. In the human carcinoma cell line T47D expressing high levels of PROG receptor, PROG did not stimulate the P0 and PMP22 promoters, whereas the promoter region of the mouse mammary tumor virus was fully activated. Thus, the activation by PROG of promoter activity of two peripheral myelin protein genes is Schwann-cell specific.     

Hyoid myotomy and suspension for obstructive sleep apnea syndrome

Hyoid bone suspension with inferior myotomy has been shown to be a successful technique in the treatment of obstructive sleep apnea. However, little mention is made in the literature concerning the details of the surgical procedure. Anatomic details have been given even less attention. This article addresses the regional anatomy, surgical technique, and materials for suspension of the hyoid bone, along with newer modifications of the procedure. Potential risks and complications are also discussed.     

The value of gallium imaging after therapy for Hodgkin's disease

BACKGROUND: Although it is used widely, the value of gallium imaging in managing Hodgkin's disease remains unclear. METHODS: A retrospective review of gallium imaging and treatment outcome in 60 patients with Hodgkin's disease treated between January 1990 and July 1995 was conducted. The minimum follow-up was 1 year. RESULTS: Based on gallium imaging, 46 patients were in complete remission (CR) after initial treatment, 10 were in partial remission (PR), and 4 had persistent or progressive disease (NR). Ten of 29 patients (34%) with gallium CR after chemotherapy subsequently recurred, compared with no recurrences in 17 patients receiving initial radiotherapy or combined chemoradiation. Eight of ten patients received further therapy after gallium PR, and nine patients remained disease free at last follow-up. Survival did not differ in patients achieving a gallium CR or PR. CONCLUSIONS: Gallium-67 imaging may help confirm the presence of active Hodgkin's disease, but was unreliable in defining disease remission after chemotherapy in this study population. Patients with a gallium PR may still have a good prognosis after additional therapy.     

MR of the eye with retrobulbar anesthesia

MR imaging with retrobulbar anesthesia was performed in eight patients with uveal melanoma. Injection of 2 mL prilocain hydrochloride in 2% epinephrin into the eye muscle cone resulted in improved image quality in seven patients, without side effects. Ocular MR imaging can be indicated to clarify indeterminate sonographic findings in cases of extrascleral growth or to exclude optic nerve invasion in patients with tumors located at the posterior pole of the globe.     

Spectroscopy of short electron beam pulses by superconducting Nb/AlOx/Nb tunnel junctions

We have used superconducting Nb/AlO_x/Nb tunnel junctions (STJs) for the spectroscopy of short electron beam pulses, which contain only a few electrons with energy ranging between 6 and 35 keV. The spectroscopy was performed by Low Temperature Scanning Electron Microscopy (LTSEM) at T=2.6 K. The spectra show that the number of beam electrons within each single pulse follows the Poisson statistics and agree well with the theoretically expected spectra. Increasing the average number of beam electrons per pulse shows that the STJ-detector response is linear up to a deposited energy of more than 500 keV. For a large average number of beam electrons the achievable energy resolution of the detector is limited by the statistics of the beam electrons and the influence of the backscattered electrons.     

Risk behavior for HIV transmission among gay men surveyed in Seattle bars

Men attending four Seattle gay bars were asked to complete a self-administered questionnaire including measures of sexual behavior, perceptions of peer norms in the area of sexual safety, personal human immunodeficiency virus (HIV) risk estimate, and knowledge and use of a variety of acquired immunodeficiency syndrome (AIDS) prevention services. Twenty-nine percent of the sample reported engaging in unprotected anal intercourse at least once during the 2 months before the survey. Differences in peer norm perceptions, age, HIV risk estimate, and intent to be sexually safe in the future were found between those engaging in unprotected anal intercourse and those not reporting unprotected anal intercourse. No significant differences were found in level of education, use of AIDS prevention services, and whether or not a person had been tested for HIV. Implications for prevention programs are discussed.     

A dynamic linearization concept for piezoelectric actuators

We present a linearization circuit based on a capacitive Wheatstone bridge that is able to set a desired polarization in a piezoactuator. The system is meant to be used for dynamic actuation in a broad frequency range. A general nonlinear model for piezoactuators is presented in which two nonlinear sub-systems are cascaded: the electric-field-to-polarization (E-P) and the polarization-to-strain (P-x) blocks. The inversion of the latter sub-system in combination with the linearization bridge results in a reduction of up to 19 dB of the harmonic distortion of the actuator's mechanical displacement.     

Correction to: Editorial

Computing and Visualization in Science - In the original publication of the article the authorship was published incorrectly. The correct authorship is given in this correction