Increased platelet-monocyte aggregation in male claudicants with the Pl(A1/A2) polymorphism of Gp IIb/IIIa.

OBJECTIVES: To investigate the relationship between the Pl(A1/A2) polymorphism and platelet activation and aggregation in patients with Peripheral Arterial Disease (PAD). DESIGN: A prospective single-centre cohort study. METHODS: 45 patients with PAD on aspirin 75mg were recruited and phenotyped/genotyped for the Gp IIb/IIIa Pl(A1/A2) polymorphism. Platelet-Monocyte Aggregation (PMAs) was evaluated using flow-cytometry. RESULTS: The formation of PMAs in the Pl(A2) group was higher but not statistically significant (p=0.17). However, when males were analysed separately, the formation of PMAs was significantly higher in the Pl(A2) group (p=0.0192). No difference was seen in the females. CONCLUSIONS: In this study we show that the Pl(A1/A2) polymorphism primarily affects the aggregation of platelets to monocytes in males. The effect is not observed in females and understanding the mechanism behind this may help elucidate the way the polymorphism alters platelet function in the presence of aspirin.

Cryoplasty for peripheral vascular disease.

BACKGROUND: In the UK, symptomatic peripheral arterial disease (PAD) occurs in 5 to 7% of people over the age of 55 years. Cryoplasty offers a new approach by combining the dilation force of balloon angioplasty with the delivery of cold thermal energy to the vessel wall. Cryoplasty is thought to provoke apoptosis rather than necrosis in the arterial smooth muscle cells and thus has the theoretical advantage of reduced myointimal hyperplasia in long-term patency. As it is an emerging therapy, safety and efficacy questions remain. This systematic review evaluates the treatment and provide focus for further research in the field. OBJECTIVES: To assess the efficacy of, and complications associated with, cryoplasty for maintaining patency in the iliac or infrainguinal arteries. SEARCH STRATEGY: We searched the Specialized Register of the Cochrane Peripheral Vascular Diseases Group (inception to August 2007), the Cochrane Central Register of Controlled Trials (CENTRAL) in The Cochrane Library 2007, Issue 3, along with MEDLINE (1966 to August 2007) and EMBASE (1980 to August 2007). SELECTION CRITERIA: Trials in which patients with peripheral arterial disease (PAD) of the iliac or infrainguinal arteries were randomised to cryoplasty with or without another procedure versus a procedure without cryoplasty. This includes trials where all patients receive angioplasty and the randomisation is for cryoplasty versus none. DATA COLLECTION AND ANALYSIS: Studies identified for potential inclusion were independently assessed for inclusion by at least two authors, with excluded trials arbitrated by the third author. As no randomised controlled trials of cryoplasty were found, no statistical analyses were performed. MAIN RESULTS: No randomised controlled trials of cryoplasty were identified. AUTHORS' CONCLUSIONS: The benefit of cryoplasty over conventional angioplasty has not been established as no randomised controlled trials exist to properly evaluate this method. Technical success and primary patency rates seen in the prospective series are encouraging and may suggest a future role for cryoplasty in the treatment of PAD, but cannot be reliably interpreted due to the nature of the studies.

Lower-limb revascularization and major amputation rates in England.

BACKGROUND: The aim was to establish national data for lower-limb revascularization and major amputation procedures performed in England. METHODS: Data for lower-limb revascularization procedures and major amputations were collected from the Hospital Episode Statistics (finished consultant episodes) which is published yearly by the Department of Health. Transluminal procedures were analysed from 1998 onwards. Age adjustment was performed according to figures for the resident population of England in the interval studied. RESULTS: In all age groups, revascularization rates initially increased to a peak in the mid-1990 s. This was followed by a steady decline in procedures to the present day. However, amputations gradually increased in the 45-64-years age group and showed only a slight decline in the 65-74-years age group. Among patients aged over 75 years there was a marked decline from the mid-1990 s to present-day. Data for diabetics showed similar trends. CONCLUSION: The national rate of amputation initially rose despite an increasing number of vascular interventions. It is significant, however, that among patients aged over 75 years this has been followed by a decrease in both revascularization procedures and amputation rates to present levels, the lowest for 14 years.

Neutron flux-density and secondary-particle energy spectra at the 184-inch synchrocyclotron medical facility.

We have identified the sources of neutron production in the beam transport system of the 720-MeV helium beam used for radiation therapy at the 184-in synchrocyclotron of the Lawrence Berkeley Laboratory, and determined their magnitude. Measurements with activation detectors of differing energy response were used to unfold secondary particle spectra at various locations on the patient table. The effect of charged particles was estimated using a calculation of neutron-flux densities derived from published cross sections. The absorbed dose, as a function of distance from the beam axis, was calculated using the unfolded spectra and evaluated fluence-to-dose conversion factors. The values of absorbed dose obtained from the unfolding of experimental data agree with the values obtained from the calculated spectra within the estimated uncertainty of +/- 25%. These values are approximately 5 X 10(-3) rad on the beam axis and approximately 1 X 10(-3) rad at distances greater than 20 cm, perpendicular to the beam axis, per rad deposited by the incident alpha-particle beam in the plateau. Estimates of upper limits of dose to two critical organs, the lens of the eye and red bone marrow, are approximately 25 rad and approximately 5 rad, respectively, for a typical treatment plan.