Regulation of p53 levels by the E1B 55-kilodalton protein and E4orf6 in adenovirus-infected cells

The adenovirus type 5 243R E1A protein induces p53-dependent apoptosis in the absence of the 19- and 55-kDa E1B polypeptides. This effect appears to result from an accumulation of p53 protein and is unrelated to expression of E1B products. We now report that in the presence of the E1B 55-kDa polypeptide, the 289R E1A protein does not induce such p53 accumulation and, in fact, is able to block that induced by E1A 243R. This inhibition also requires the 289R-dependent transactivation of E4orf6 expression. E4orf6 is known to form complexes with the E1B 55-kDa protein and to function both in the transport and stabilization of viral mRNA and in shutoff of host cell protein synthesis. We demonstrated that the block in p53 accumulation is not due to the generalized shutoff of host cell metabolism. Rather, it appears to result from a mechanism targeted specifically to p53, most likely involving a decrease in the stability of p53 protein. The E1B 55-kDa protein is known to interact with both E4orf6 and p53, and as demonstrated recently by others, we showed that E4orf6 also binds directly to p53. Thus, multiple interactions between all three proteins may regulate p53 stability, resulting in the maintenance of low levels of p53 following virus infection.     

A comparative clinical evaluation of the Wisdom Straight, Plaque Control and Angled toothbrushes compared to the Oral-B 35

PURPOSE: Many patients attend orthopedic departments complaining of pain on the plantar aspect of the calcaneum. The symptoms may subside spontaneously, but often persist. Treatment is usually by local injection of a corticosteroid, orthopedic devices or other standard treatment. If these methods fail, X-ray treatment may be considered. The efficacy of radiotherapy of the calcaneal spur was evaluated. PATIENTS AND METHODS: From April 1981 through December 1991, 18 patients with painful heel were irradiated mostly with the caesium or telecobalt unit, usually with a dose of 4 times 0.5 Gy. Among these patients, 12 could be followed up during a prolonged period on the basis of questionnaires. RESULTS: According to the categories of v. Pannewitz 17% of the patients were pain-free by the end of the treatment course, 22% showed marked improvement, 33% showed improvement and in 28% the pain was not influenced. Over an average of 41.5 months 58% of the patients reported freedom from pain. CONCLUSIONS: Low-dose radiotherapy appears to relieve the painful heel syndrome in a high proportion of patients. The overall treatment risk appears to be very small. The mechanism of low-dose radiotherapy is unknown.     

Mechanisms underlying induction of homosynaptic long-term depression in area CA1 of the hippocampus

The mechanisms responsible for long-lasting, activity-dependent decreases in synaptic efficacy are not well understood. We have examined the initial steps required for the induction of long-term depression (LTD) in CA1 pyramidal cells by repetitive low frequency (1 Hz) synaptic stimulation. This form of LTD was synapse specific, was saturable, and required activation of post-synaptic NMDA receptors. Loading CA1 cells with the Ca2+ chelator BAPTA prevented LTD, whereas lowering extracellular Ca2+ resulted in the induction of LTD by stimulation that previously elicited long-term potentiation. Following LTD, synaptic strength could be increased to its original maximal level, indicating that LTD is reversible and not due to deterioration of individual synapses. Induction of homosynaptic LTD therefore requires an NMDA receptor-dependent change in postsynaptic Ca2+ which may be distinct from that required for long-term potentiation.     

An in vitro comparison of apical microleakage after obturation with JS Quick-Fill or lateral condensation

In order to investigate the blood supply of osteo-periosteal flap of lateral inferior part of tibia, 40 lower limbs of adult cadavers were observed. The result showed that the superior malleolar branch was the biggest branch on the lateral inferior part of tibia and served as the main blood supply to the above area. It originated from the anterior tibial artery, 3.1 +/- 0.8 cm above the intermalleolar line. During its way to the anterior border of the tibia, it gave out the ascending and descending branches. The ascending branch was along the anterior border upward and anastomosed with the musculo-periosteol branch of the anterior tibial artery at the level of 6.3 +/- 1.3 cm above the intermalleolar line. The decending branch was anastomosed with the anterior medial malleolar artery. For the anastomosis between the superior malleolar branch with the peripheral vessels, the osteo-periosteol flap could be designed at the lateral side of the lower part of tibia in size of 8-10 cm x 4-6 cm. This was a new donor area of osteo-periosteol flap for repair of non-union of bone in lower end of tibia or arthrodesis of the ankle joint.     

A comparison of two computer access systems for functional text entry

OBJECTIVE: Functional written communication, an important goal in the rehabilitation of persons with tetraplegia, frequently is met through the use of personal computers and alternative computer access systems. To make informed decisions about alternative access systems, the therapist needs information on the efficacy of the available choices. The purpose of this study was to investigate the effectiveness of two commercially available systems for text entry, the traditional mouthstick and the Prentke Romich HeadMaster. METHOD: Participants were a 25-year-old man and 76-year-old woman who both functioned at a C5 neurological level. Neither participant had previous experience with either system for text entry. A single-subject research design was used whereby Participant 1 experienced six phases of treatment (i.e., CBCBCB, where C = mouthstick and B = HeadMaster), and Participant 2 experienced four phases of treatment (i.e., BCBC). RESULTS: Participant 1 achieved a maximum rate of text entry of 5.85 wpm with both the HeadMaster and the mouthstick, whereas Participant 2 achieved a maximum rate of 7.15 wpm with the mouthstick and 4.85 wpm with the HeadMaster. Results from this study were similar to the results from previous comparison studies of persons with severe disabilities who had no experience with alternative computer access systems. CONCLUSION: Both participants were able to use both systems successfully; however, their respective rates of text entry were too slow to be functional in most employment situations.