Induction of Fas ligand expression by HIV involves the interaction of Nef with the T cell receptor zeta chain

During HIV/SIV infection, there is widespread programmed cell death in infected and, perhaps more importantly, uninfected cells. Much of this apoptosis is mediated by Fas-Fas ligand (FasL) interactions. Previously we demonstrated in macaques that induction of FasL expression and apoptotic cell death of both CD4(+) and CD8(+) T cells by SIV is dependent on a functional nef gene. However, the molecular mechanism whereby HIV-1 induces the expression of FasL remained poorly understood. Here we report a direct association of HIV-1 Nef with the zeta chain of the T cell receptor (TCR) complex and the requirement of both proteins for HIV-mediated upregulation of FasL. Expression of FasL through Nef depended upon the integrity of the immunoreceptor tyrosine-based activation motifs (ITAMs) of the TCR zeta chain. Conformation for the importance of zeta for Nef-mediated signaling in T cells came from an independent finding. A single ITAM motif of zeta but not CD3epsilon was both required and sufficient to promote activation and binding of the Nef-associated kinase (NAK/p62). Our data imply that Nef can form a signaling complex with the TCR, which bypasses the requirement of antigen to initiate T cell activation and subsequently upregulation of FasL expression. Thus, our study may provide critical insights into the molecular mechanism whereby the HIV-1 accessory protein Nef contributes to the pathogenesis of HIV.

Prejunctional muscarinic receptors regulating neurotransmitter release in airways

Prejunctional pA2 values of five muscarinic antagonists were determined in the guinea-pig trachea under stimulation conditions in which the antagonists alone did not enhance acetylcholine release. The antagonists were partly selective at M1 (pirenzepine), M2 (AQ-RA 741, himbacine) and M3 receptors (hexahydrosiladifenidol, dicyclomine). The profile of the antagonist affinities was different from that obtained at cardiac M2 receptors but resembled the profile reported in the literature for the cloned m4 receptor. This suggests that autoinhibition of acetylcholine release in the trachea is mediated via M4 receptors.

Enteroaggregative and enterotoxigenic Escherichia coli among isolates from patients with diarrhea in Austria

In a 3-month prospective study among 203 Austrian outpatients with diarrhea, the role of pathogenic Escherichia coli and the use of the polymerase chain reaction in screening Escherichia coli isolates from clinical stool specimens were evaluated. Enteroaggregative Escherichia coli and enterotoxigenic Escherichia coli combined were identified as the second most frequent cause of diarrhea. Of a total of 85 bacterial pathogens isolated from 80 patients, 15 were pathogenic Escherichia coli, 13 enteroaggregative Escherichia coli and two enterotoxigenic Escherichia coli. Enteropathogenic, enteroinvasive, and enterohemorrhagic Escherichia coli isolates were not detected.

Aplidioxins A and B, two new dibenzo-p-dioxins from the ascidian aplidiopsis ocellata

Two new substituted dibenzo-p-dioxins, aplidioxins A (1) and B (2), were isolated from the ascidian Aplidiopsis ocellata. The structures of these compounds were elucidated by a combination of 1D and 2D NMR spectroscopy and an X-ray analysis of aplidioxin A.

Aurantoside C, a new tetramic acid glycoside from the sponge Homophymia conferta

A new tetramic acid glycoside, aurantoside C (3), was isolated from the sponge Homophymia conferta and the structure was determined by detailed 1D and 2D NMR analysis of the natural product and a hexaacetate derivative.

New diterpene isonitriles from the sponge Phakellia pulcherrima

Seven new diterpene isonitriles and isothiocyanates were isolated from the sponge Phakellia pulcherrima along with eight known ones. Six of the new compounds, 9-14, and the eight known ones, 1-8, belong to the kalihinol family of diterpenes. Structures were determined from spectroscopic data. This is the first report of diterpenes from sponges of this genus. All of the other kalihinol diterpenoids have been isolated from the sponge Acanthella cavernosa collected in diverse locations.

Transgenic resistance to cucumber mosaic virus in tomato: blocking of long-distance movement of the virus in lines harboring a defective viral replicase gene

ABSTRACT Tomato breeding lines were transformed with a defective replicase gene from RNA 2 of cucumber mosaic virus (CMV). A total of 63 transformants from five tomato genotypes were evaluated for resistance to CMV strains. The responses of R1 transgenic offspring fit into three categories: fully susceptible lines (44%), fully resistant lines (8%), and an intermediate-type mixture of susceptible and resistant seedlings in variable proportions (48%). Further characterization of the response of two highly resistant lines was performed by mechanical inoculation, aphid transmission, or grafting experiments. No virus was detected in noninoculated leaves from these lines, although a low level of virus accumulated initially in the inoculated leaf. The homozygous R2 plants and further generations that were evaluated (up to R5) showed resistance to the Fny-CMV strain, two Israeli isolates tentatively classified as subgroup IA, and K-CMV (a representative of subgroup IB). These lines were partially resistant to LS-CMV (a representative of subgroup II) when a high-virus-titer inoculum was used. Expression of the viral transgene was verified in these lines; however, the expected translation product was not detectable. In grafting experiments, we demonstrated that CMV virions were blocked in their ability to move from infected rootstocks of nontransformed tomato or tobacco into the transgenic scions. Interestingly, virions could not move through a transgenic intersection into the upper scion. These results provide an additional indication that replicase-mediated resistance affects long-distance movement.

Massive intracranial bleeding requiring emergency splenectomy in a patient with CMV-associated thrombocytopenia

We describe a previously healthy male patient, with severe immune thrombocytopenic purpura (ITP) following CMV infection which was refractory to steroids and intravenous immunoglobulin, who developed massive intracranial bleeding. Despite an extremely low platelet count (2x10(9)/liter) which was refractory to platelet transfusions, successful emergency splenectomy was performed, with rapid resolution of the thrombocytopenia. Bleeding complications are extremely rare in viral-associated ITP. Emergency splenectomy should be considered in the presence of life-threatening bleeding when other modalities fail to produce a rise in the platelet count. Infection with CMV should be ruled out in cases of severe, treatment-resistant ITP.

Single-dose antibiotic prophylaxis in transurethral resection of the prostate: a prospective randomized trial

OBJECTIVE

To evaluate the efficacy of single-dose antibiotic prophylaxis in transurethral resection of the prostate (TURP).

PATIENTS AND METHODS

A total of 139 patients were entered into a prospective randomized trial comparing single-dose antibiotic prophylaxis with no antibiotic before surgery. Twelve patients were excluded because they had significant bacteriuria before surgery (defined as > or = 10(5) bacteria/mL). Of the remaining 127 patients, 62 were allocated to the single-dose group (A) and 65 to the no-antibiotic group (B). All 62 patients in group A received 1 g of ceftriaxone intravenously 1-2 h before surgery with the anaesthetic premedication, the 65 in group B receiving none. Urine cultures were collected post-operatively as the catheter was removed and again 4 weeks after hospitalization.

RESULTS

The incidence of post-operative bacteriuria was statistically significantly different, occurring in five patients (9%) in group A and 16 patients (26%) in group B (Fisher's exact test, one-tail P = 0.009). There was no significant difference between the groups 4 weeks after hospitalization. The overall incidence of bacteriuria post-operatively and 4 weeks after hospitalization was 11 patients (18%) in group A and 22 patients (34%) in group B (P = 0.03).

CONCLUSION

Single-dose antibiotic prophylaxis with 1 g of ceftriaxone intravenously is effective in patients undergoing TURP and is recommended for such surgery.

Vitamin E: the radical protector

Since its discovery and isolation the importance of vitamin E in maintaining normal physiologic processes and its value in treating various disease states have been the subject of much controversy. It was our intention to review and highlight some of the arguments and problems regarding the usefulness of vitamin E and to try to put them into proper perspective. The major area of interest concerning vitamin E lies essentially in its role in preventing damage caused by free radicals. The latter are now known to play an important role in radiation induced carcinogenesis, photoaging and photosensitization. The chemistry of vitamin E, its physiological function as a major antioxidant and its interaction with other antioxidants are described by the sum of animal studies, in vitro research and epidemiological investigations. In preparing the current data, it appeared that despite the controversy and conflicting results the body of literature as a whole judges vitamin E to be useful as an antioxidant. Although, in principle, the use of vitamin E can be quite advantageous, the manner of its administration, especially regarding topical application, remains unclear.

MRI evaluation of thermal ablation of tumors with focused ultrasound

MRI was used to target and evaluate the tissue effects of focused ultrasound ablation on tumors implanted in the skeletal muscle of rabbits in vivo. First, MRI was used to localize the tumors and plan the ultrasound therapy. Second, temperature-sensitive phase-difference images were acquired to monitor the location of the ultrasound focus and to estimate the effects of temperature rise. After the treatment, the spatial and temporal temperature profiles for defining boundaries of tissue coagulation were calculated. Finally, these boundaries were compared to T2-weighted and contrast-enhanced T1-weighted images obtained immediately after therapy. The results indicate that using MRI for planning and evaluating focused ultrasound surgery is feasible. We showed a linear relationship between applied power and shifts in the proton resonant frequency. Fluctuations in the location of the focus about the target location were on the order of the resolution of the MR images. The temperature rise and lesion size varied significantly. Regions of tissue coagulation calculated from MR data correlated well with post-therapy imaging.

Characterization of the muscarinic receptor subtype(s) mediating contraction of the guinea-pig lung strip and inhibition of acetylcholine release in the guinea-pig trachea with the selective muscarinic receptor antagonist tripitramine

1. The muscarinic receptor subtypes mediating contraction of the guinea-pig lung strip and inhibition of the release of acetylcholine from cholinergic vagus nerve endings in the guinea-pig trachea in vitro have previously been characterized as M2-like, i.e. having antagonist affinity profiles that are qualitatively similar but quantitatively dissimilar compared to cardiac M2 receptors. The present study sought to establish definitely the identity of these receptor subtypes by using the selective muscarinic receptor antagonist, tripitramine. Guinea-pig atria and guinea-pig trachea (postjunctional contractile response) were included for reference. 2. It was found that tripitramine antagonized methacholine-induced contractions of the guinea-pig lung strip with pKB value of 8.76 +/- 0.05. Both the parallel shifts of the concentration-response curves and the slope of the Schild plot begin not significantly different from unity (when antagonist preincubation was for 2 h) indicated the involvement of a single population of receptors in the contractile response. From the pKB values obtained with tripitramine and a range of other selective muscarinic receptor antagonists (cf. Roffel et al., 1993), this single population of receptors can only be classified as M2-like. 3. Tripitramine antagonized methacholine-induced chronotropic and inotropic responses in guinea-pig right and left atria with apparent pKB values of 9.4-9.6. However, such values were only obtained when antagonist preincubation was relatively long and/or antagonist concentration relatively high (e.g with 1 h at 100 or 300 nM but 3 h at 30 nM). It thus appears that low concentrations of tripitramine do not readily equilibrate with M2 receptors in guinea-pig atria nor with M2-like receptors in the guinea-pig lung strip. 4. Tripitramine increased electrical field stimulation-induced cholinergic twitch contractions in guinea-pig trachea in concentrations of 0.3-100 nM, by blocking prejunctional muscarinic inhibitory autoreceptors; with higher concentrations, twitch contractions were progressively diminished, as a result of blocking postjunctional M3 receptors (apparent pKB value 6.07 +/- 0.15). The pEC20 value (-log concentration that increases twitch by 20% maximum) was 8.29 +/- 0.08, which would suggest that M4 receptors are involved in this response. 5. Oxotremorine-induced inhibition of the release of prelabelled [3H]-acetylcholine from guinea-pig trachea, under conditions where there is no auto-feedback, was blocked by tripitramine (2 h preincubation) with a pKB value of 8.56 +/- 0.06. The slope of the corresponding Schild plot was not significantly different from unity, which together with the parallel shifts of the concentration-response curves indicated the involvement of a single muscarinic receptor subtype. 6. Since the pKB value for tripitramine at prejunctional receptors in guinea-pig trachea is in between the affinities towards M2 and M4 receptors, correlation plots were constructed to compare the pKB values obtained with tripitramine and a range of other selective muscarinic receptor antagonists (cf. Kilbinger et al., 1995) to reported affinities at M1-M4 receptors. This showed rather similar distribution patterns of the data points around the line of equality in the case of M2 and M4 receptor subtypes. However, the correlation coefficient was markedly better for M2 (0.9667) than for M4 (0.5976). Since recent evidence suggests that M4 receptors are not expressed in cholinergic nerves from guinea-pig trachea, it is concluded that prejunctional muscarinic autoinhibitory receptors in this tissue exhibit an atypical M2 type character, with a pharmacological profile distinct from cardiac M2 receptors.

Combined lesions of perirhinal and entorhinal cortex impair rats' performance in two versions of the spatially guided radial-arm maze

The present study examined the effects of combined lesions of the entorhinal and perirhinal cortex (PRER) on performance of two versions of the spatially guided eigh-tarm radial maze. In the first version, all arms were baited and in each session the rats were allowed to explore the maze freely until they retrieved all of the reinforcers. PRER subjects were profoundly impaired in performance of this task, making fewer correct choices and more total errors than control subjects. In the second task, a delayed nonmatching to sample version of the radial-arm maze, each daily session was separated into two phases. In the first, predelay phase, four arms were open and the remaining four arms were blocked with clear Plexiglas barriers; subjects were permitted to visit each of the four arms and retrieve the reinforcers. In the second, postdelay phase, the subject was placed on the maze with free access to all eight of the arms, but only those arms that were blocked in the predelay phase contained reinforcers. Delays of either 10 min or 30 s separated the pre- and postdelay phases. PRER subjects were significantly impaired in their performance of this task at both delays, making fewer correct choices and more errors than controls; the magnitude of this deficit was not dependent on length of delay. These data suggest that, along with the hippocampal formation, the entorhinal and perirhinal cortices actively participate in the acquisition and performance of appetitively motivated spatial memory tasks.

Orientation program for a hospital-based dual case manager and educator role

The nurse case manager role is continually evolving. Case managers are being challenged to perform new functions. There are few articles concerning orientation programs for case managers. This article provides a successful orientation program and clinical orientation schedule for a unique unit-based nurse case manager/educator role. The orientation program is outlined based on the four competency domains of the nurse case manager/educator clinical expertise, resource management, staff education, and patient/family education. Program topics and an orientation schedule are provided.