Effect of the D3 dopamine receptor partial agonist BP897 [N-[4-(4-(2-methoxyphenyl)piperazinyl)butyl]-2-naphthamide] on L-3,4-dihydroxyphenylalanine-induced dyskinesias and parkinsonism in squirrel monkeys

Although l-3,4-dihydroxyphenylalanine (L-dopa) is one of the most effective therapies for Parkinson's disease, continued treatment may result in excessive involuntary movements known as L-dopa-induced dyskinesias (LIDs). Because LIDs can become dose-limiting, there is great interest in finding ways to ameliorate or prevent this troubling side effect of L-dopa therapy. It was recently reported that the D3 receptor partial agonist BP897 [N-[4-(4-(2-methoxyphenyl)piperazinyl)butyl]-2-naphthamide] reduces LIDs without diminishing antiparkinsonian effects of L-dopa in macaques. In the present study, we tested the effects of BP897 on LIDs in squirrel monkeys, a nonhuman primate particularly prone to dyskinesias. Parkinsonism was induced using 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine. Animals were then gavaged with L-dopa/carbidopa (7.5 or 15 mg/kg/dose) without and with BP897. The effects of BP897 treatment were evaluated on several components of LIDs, including time course, peak dyskinesias, and area under the curve (AUC), a measure that encompasses both peak and duration of the response. Analyses of the time course and overall dyskinetic response (AUC) showed that BP897 significantly reduced LIDs but at the expense of the antiparkinsonian effect of L-dopa. BP897 had no significant effect on peak dyskinesias. Correlation studies showed that beneficial effects of BP897 on dyskinesias were linked to a decline in the antiparkinsonian action of L-dopa. Analyses of a subgroup of animals with mild/moderate parkinsonism yielded comparable results. Thus, in squirrel monkeys in contrast to macaques, BP897 fails to exert an antidyskinetic effect without diminishing the antiparkinsonian effects of L-dopa. These results suggest that BP897 may be less effective than originally anticipated for treating LIDs in Parkinson's disease.     

SARS outbreak, Taiwan, 2003

We studied the severe acute respiratory syndrome (SARS) outbreak in Taiwan, using the daily case-reporting data from May 5 to June 4 to learn how it had spread so rapidly. Our results indicate that most SARS-infected persons had symptoms and were admitted before their infections were reclassified as probable cases. This finding could indicate efficient admission, slow reclassification process, or both. The high percentage of nosocomial infections in Taiwan suggests that infection from hospitalized patients with suspected, but not yet classified, cases is a major factor in the spread of disease. Delays in reclassification also contributed to the problem. Because accurate diagnostic testing for SARS is currently lacking, intervention measures aimed at more efficient diagnosis, isolation of suspected SARS patients, and reclassification procedures could greatly reduce the number of infections in future outbreaks.     

Induction of unresponsiveness limits tumor protection by adoptively transferred MDM2-specific cytotoxic T lymphocytes

There is evidence showing that high avidity CTLs can be more effective than low avidity CTLs for adoptive tumor immunotherapy. Because many T cell-recognized tumor antigens are nonmutated self-proteins, tolerance mechanisms are likely to render high avidity T cells unresponsive or cause T cell elimination by clonal deletion. We recently used the allo-restricted strategy to circumvent immunologic tolerance to a ubiquitously expressed tumor-associated protein, MDM2, and raised high avidity CTLs in humans and in mice. In this study, we investigated whether high avidity MDM2-specific CTLs can mediate tumor protection without causing damage to normal tissues in mice. Although the CTLs prolonged survival of tumor-bearing mice without causing damage to normal tissues, tumor protection was incomplete. We show that tumor growth occurred despite the continued presence of MDM2-specific CTLs and the continued susceptibility of tumor cells to CTL killing. However, analysis of the CTLs revealed that they had been rendered unresponsive in vivo because they did not produce interferon gamma in response to antigen-specific stimulation. These experiments suggest that induction of unresponsiveness may be an important mechanism limiting the efficacy of adoptive CTL therapy.     

Triflamp, a snake venom metalloproteinase, reduces neutrophil-platelet adhesion through proteolysis of PSGL-1 but not glycoprotein Ib alpha

Triflamp, a metalloproteinase isolated from Trimeresurus flavo-viridis, inhibits heterotypic adhesion between platelets and neutrophils. Coincubation studies demonstrate that direct interaction of triflamp with neutrophils is sufficient to inhibit the formation of neutrophil-platelet complexes. Its anti-adhesive effect is in a concentration- and incubation time-dependent manner. Triflamp reduces the expression of P-selectin glycoprotein ligand-1 (PSGL-1) on neutrophils and glycoprotein (GP) Ibalpha on platelets as probed by flow cytometry and Western blot. Moreover, triflamp disrupts P-selectin-mediated adhesion by cleaving PSGL-1 from the neutrophil surface. There are obvious differences regarding PSGL-1 proteolysis by triflamp and cathepsin G. Besides the NH2-terminus of PSGL-1, other sites are truncated by triflamp. The inhibitory effect of triflamp on PSGL-1 expression was prevented by pretreatment with a metalloproteinase inhibitor, phenanthroline. However, triflamp-treated platelets fully keep the ability for binding to PAF- or fMLP-stimulated neutrophils. Our results indicate that degradation of platelet GPIb alpha by triflamp does not interfere with neutrophil-platelet adhesion. Its effect on neutrophil PSGL-1 appears to be a critical factor for its inhibition on neutrophil-platelet interaction.     

Paraparesis as the major initial presentation of aortic dissection: report of four cases

Aortic dissection, which typically manifests as sudden tearing or migratory pain, is a well-known medical emergency. However, in 5% of aortic dissection patients, there is no pain. In these patients, the diagnosis depends on the development of neurologic complications. After analyzing the initial symptoms of a series of patients with aortic dissection, we found 4/211 (1.9%) patients suffered from paraparesis. We suggested that the mid- or low thoracic cord be most vulnerable site during acute aortic dissection. This report highlighted the importance of considering the diagnosis of aortic dissection in a patient with a history of acute onset of transient or permanent neurological symptoms in the lower limbs. Whether paraparesis can be an indicator of the prognosis of aortic dissection requires further researches.     

Post-operative adjuvant thoracic radiotherapy for patients with completely resected non-small cell lung cancer with nodal involvement: outcome and prognostic factors

The purpose of this study was to analyse the outcome and prognostic factors of non-small cell lung cancer (NSCLC) patients with nodal disease treated by complete tumour resection followed by radiotherapy alone. Between October 1990 and October 1999, 49 NSCLC patients with N1 or N2 stage were treated with complete resection of tumour followed by post-operative radiotherapy in our department. The radiation was delivered with 10 MV X-rays given 5 days per week at 1.8-2 Gy per fraction. Total doses ranged from 40 Gy to 64.8 Gy, with a median dose of 55.8 Gy. All patients had at least 30 months of follow-up. The 5 year overall survival rate (OS), local control rate (LC) and distant metastasis-free rate (DMF) were 34%, 52% and 29%, respectively. In multivariate analysis, stage and margin were found to influence OS. The total number of involved lymph nodes and positive margins were significant factors for LC. Only N stage was found to correlate with DMF. In conclusion, patients with multiple involved lymph nodes, advanced stage or positive surgical margins had a poor outcome even with post-operative radiotherapy. Based on these prognostic factors, new therapeutic regimens and modalities for NSCLC need to be further investigated.