Transcription-targeted gene therapy for androgen-independent prostate cancer

The Escherichia coli enzyme (purine nucleoside phosphorylase, PNP) gene is delivered directly into PC3 tumors by one injection of replication-deficient human type-5 adenovirus (Ad5). Expressed PNP converts the systemically administered prodrug, 6MPDR, to a toxic purine, 6MP, causing cell death. We sought to increase the specificity of recombinant Ad vectors by controlling PNP expression with the promoter region from the androgen-dependent, prostate-specific rat probasin (Pb) gene. To increase its activity, the promoter was combined with the SV40 enhancer (SVPb). Cell lines were transfected with plasmids containing both a reporter gene, under SVPb control, and a reference gene cassette to allow normalization of expression levels. Plasmids expressed approximately 20-fold more reporter in prostate cancer than in other cells, but surprisingly, the SVPb element was both androgen-independent and retained substantial prostate specificity. Killing by Ad5-SVPb-PNP vector of cell lines cultured with 6MPDR for 6 days was 5- to 10-fold greater in prostate cancer than in liver or lung cells. In vivo, a single intratumoral injection of Ad5-SVPb-PNP (4 x 10(8) pfu), followed by 6MPDR administration twice daily for 6 days, significantly suppressed the growth of human prostate tumors in nude mice and increased their survival compared to control animals. Thus, the androgen-independent, prostate-targeting Ad5 vector reduces human prostate cancer growth significantly in vitro and in vivo. This first example of an androgen-independent vector points the way toward treatment of emerging androgen-independent prostate cancer in conjunction with hormone ablation therapy at a time when the tumor burden is low.     

Increased brainstem excitability in stiff-person syndrome

The recovery cycle of the R2 component of the blink reflex was studied in five patients with stiff-person syndrome (SPS) and in seven healthy control subjects. R2 recovery was enhanced in patients with SPS. This result is suggestive of hyperexcitability of brainstem interneuronal circuits in SPS. Hyperexcitability may result from abnormal input from suprasegmental structures or loss of inhibition by interneurons and is compatible with the proposal that there is a widespread dysfunction of central inhibitory mechanisms in SPS.     

Low dose intraarterial thrombolysis with tissue plasminogen activator: does it deliver as promised?

The widespread use of intraarterial thrombolytic therapy has been based on perceived benefits over operative treatment and the downgrading of the magnitude of subsequent surgery. Thirty-three patients who had thrombolysis for peripheral artery occlusion were retrospectively analyzed at St. James's Hospital from 1991 to 1997. One patient received streptokinase unsuccessfully. Five other patient's records were inadequate for analysis. Twenty-seven patient's notes were analyzed for risk, duration of occlusion, duration of treatment, dosage of tissue plasminogen activator (tPA) and conduits thrombolysed. There were 15 males and 12 females. The mean age was 62 years (range, 20-87). Fourteen were current or reformed smokers. Five were diabetic. Indications for treatment included acute graft occlusion (n=13), embolus (n=6), and primary and secondary arterial thrombosis (n=8). Duration of occlusion was less than 24 hours in seven, 1 to 7 days in ten, and more than 7 days in ten patients. Twelve (44.44%) patients had complete clot lysis, four (14.81%) had partial clearance, and 11 (40.74%) remained occluded. Eight (29.63%) had serious complications including one death. Eighteen (66.66%) patients needed further surgical intervention to maintain graft patency. Data were analyzed using the chi-square and pooled t test. No significant difference was observed in results from thrombolysis from different conduits, gender, etiology, or smoking history. Increased duration of tPA administration was associated with an increased risk of failure. Administration of total dosages greater than 60 mg was associated with a higher risk of failure. Diabetics had a poor outcome (p=0.0520). Only 44 % of patients successfully underwent lysis. A primary surgical option may be a more sensible course than lysis, given that the vast majority of patients ended up having surgery anyway.     

The prevalence of coeliac disease among female subjects having bone densitometry

Background  

Osteoporosis frequently complicates coeliac disease but most studies focus on symptomatic patients at the time of diagnosis. Screening tests have revealed that many individuals with coeliac disease have mild, atypical, or absent symptoms.     

颅内动脉瘤栓塞后并发脑缺血的原因分析

1 临床资料我们总结2004-02/2004-06在第四军医大学唐都医院神经外科住院行栓塞治疗颅内动脉瘤患者27(男12,女15)例,年龄32～72岁.     

Unusual presentation of perirenal lung metastases

Lung cancer is not commonly known to metastasise to the perirenal space, with only five such cases previously published. We present an unusual case of perirenal lung metastases manifesting as diffuse perinephric stranding which to our knowledge has not been described before.     

Structural determinants in adenovirus 12 E1A involved in the interaction with C-terminal binding protein 1

The interaction between the C-terminal binding protein 1 (CtBP-1) and purified Ad12 E1A protein has been examined through the use of a combination of biophysical techniques. A fragment equivalent to the 77 C-terminal amino acids of Ad12 E1A (Ad12 77-a.a. E1A) was generated by limited proteolysis of Ad12 266-a.a. E1A at Phe(187) and/or Tyr(189) using chymotrypsin. The impact of deletion of the 189 N-terminal amino acids from E1A on the equilibrium dissociation constant K(d) for binding to CtBP was assessed using ELISA in vitro binding assays and intrinsic fluorescence spectroscopy. Values of K(d) of 4.0 and 38 nM were determined for full-length and truncated forms of E1A, respectively. Circular dichroism spectroscopic studies revealed that the conformation adopted by these polypeptides is dependent on the surrounding environment, which is predominately randomly folded when free in solution, but adopting a more ordered alpha-helical secondary structure in the presence of trifluoroethanol. Using nuclear magnetic resonance (NMR) spectroscopy to examine the interaction between Ad E1A and CtBP it was observed that the chemical shift positions of individual backbone amide nitrogen atoms were well resolved in (15)N-(1)H-HSQC NMR spectra performed on samples of isotopically (15)N-labeled Ad12 77-a.a. E1A. In the presence of CtBP, signals of backbone amide nitrogen atoms displayed increased linewidth consistent with an increase in molecular mass upon binding CtBP. In addition, some signals that have been attributed to Val(254/256) and Leu(259), and reside within the binding site for CtBP on E1A, are shifted in the (15)N- and/or (1)H-dimensions, defining specific contacts between E1A and CtBP. These data suggest that structural determinants in the C-terminal PXDLS binding motif in the rest of exon 2 and in exon 1 all contribute to optimizing the conformation of the binding site on Ad12 E1A for CtBP. However, no interaction was observed between CtBP and truncated Ad12 E1A, which no longer contained the C-terminal binding motif.     

High prevalence of HIV infection among homeless and street-involved Aboriginal youth in a Canadian setting

Aboriginal people experience a disproportionate burden of HIV infection among the adult population in Canada; however, less is known regarding the prevalence and characteristics of HIV positivity among drug-using and street-involved Aboriginal youth. We examined HIV seroprevalence and risk factors among a cohort of 529 street-involved youth in Vancouver, Canada. At baseline, 15 (2.8%) were HIV positive, of whom 7 (46.7%) were Aboriginal. Aboriginal ethnicity was a significant correlate of HIV infection (odds ratio = 2.87, 95%CI: 1.02 – 8.09). Of the HIV positive participants, 2 (28.6%) Aboriginals and 6 (75.0%) non-Aboriginals reported injection drug use; furthermore, hepatitis C co-infection was significantly less common among Aboriginal participants (p = 0.041). These findings suggest that factors other than injection drug use may promote HIV transmission among street-involved Aboriginal youth, and provide further evidence that culturally appropriate and evidence-based interventions for HIV prevention among Aboriginal young people are urgently required.