Venous clots: evaluation with MR imaging

In vitro and in vivo studies were performed to determine the proton relaxation and imaging characteristics of static blood and acute and organized clot in canine jugular veins. In vivo, it was found that two inversion recovery sequences using a short inversion time (100 msec) demonstrated better differentiation of signal intensity of intravascular clot from surrounding soft tissues than did standard T1- and T2-weighted sequences. In vitro, quantitative measurements showed marked reduction of both T1 and T2 relaxation time of acute clot compared with stagnant blood. In addition, the T1 relaxation time, and to a lesser extent the T2 relaxation time, shortened as the clot aged, indicating a potential role for magnetic resonance imaging in determining the age of venous thrombi.     

Surgical versus nonoperative treatment of symptomatic carotid stenosis. 211 patients documented by intravenous angiography.

From 1980 through 1982, intravenous extracranial digital subtraction angiography (DSA) was performed in 6684 patients at the Cleveland Clinic. Of these, 211 previously unoperated patients had prior transient ischemic attacks (TIA) or strokes in conjunction with greater than 50% carotid stenosis on unequivocal DSA studies. Nonoperative management was employed in 126 patients, including 120 (84%) who received antiplatelet therapy or formal anticoagulation. The remaining 85 patients underwent carotid endarterectomy. During a mean follow-up interval of 36 months, there was no overall difference in survival, late TIA, or stroke between the nonoperated and surgical cohorts. However, parity was maintained in these groups only because of the prevalence of intermediate (50-69%) stenotic lesions and stable internal carotid occlusions in the nonoperated group. Carotid endarterectomy provided superior stroke prevention for patients with greater than 70% unilateral stenosis (p = 0.04), for those with greater than 50% bilateral stenosis (p = 0.004), and for those with internal carotid occlusions associated with greater than 50% contralateral stenosis (p = 0.03). The special risk of such discrete subsets should be recognized in order to plan appropriate treatment at the present time, as well as to conduct safe clinical trials in the future.     

Precise intraoperative location of gastrointestinal bleeding with a hand-held counter. Work in progress

The nuclear medicine bleeding scan is frequently insufficient to locate sites of bleeding precisely, in spite of its great sensitivity. A small, hand-held Geiger-Müller counter, placed directly on exposed intestine in the operating room, enables precise location of the probable bleeding site. In three patients, the technique allowed a minimal amount of intestine to be resected, distinguished between large- and small-intestinal hemorrhage, and eliminated other foci as sites of bleeding.     

Orchidectomy enhances the effects of phenylephrine in rat isolated portal vein

1. Orchidectomy results in long‐term testosterone deprivation similar to that observed in male clinical pathologies, such as hypogonadism and age‐related reductions in plasma testosterone concentrations. Although the vascular effects of these sorts of hormone deprivations are known in arteries, they have not been studied to the same extent in veins. 2. The aim of the present study was to determine the effect of orchidectomy, with or without subsequent testosterone replacement (started 23 days after orchidectomy; 10 mg/kg, i.m., testosterone propionate once every 5 days for 3 weeks), on responses of rat isolated portal veins and vena cavae to exogenous phenylephrine (PE). Isolated vessels were mounted in an organ bath and concentration–response curves constructed to PE (10^?10–10^?4 mol/L), endothelin (ET; 10^?10–10^?5 mol/L) and KCl (10^?2–1.2 × 10^?1 mol/L; as a control). 3. Orchidectomy had no effect on contractile responses of either the portal vein or vena cava to KCl. However, orchidectomy enhanced the maximum response (R_max) of the portal vein, but not the vena cava, to PE. Testosterone replacement had no effect on these responses. The effects of orchidectomy on the R_max to PE in portal veins were not altered by the nitric oxide synthase inhibitor N^G‐nitro‐l‐ arginine methyl ester (10^?4 mol/L) alone or combined with 10^?5 mol/L indomethacin (a non‐selective cyclo‐oxygenase inhibitor), but they were abolished following treatment of isolated vessels with the ET_A and ET_B receptor antagonists BQ‐123 and BQ‐788 (both at 10^?6 mol/L). Orchidectomy did not alter portal vein responses to the application of exogenous ET. 4. The results of the present study indicate that orchidectomy‐induced decreases in plasma testosterone can increase the venoconstrictor effects of PE on the portal vein and that this effect involves activation of both ET_A and ET_B receptors by locally produced ET.     

PLANNING OF A COMMUNITY-BASED APPROACH TO INJURY CONTROL AND SAFETY PROMOTION IN A RURAL COMMUNITY

ABSTRACT: This paper describes the planning of a community-based approach to injury control and safety promotion, the Kolan Injury Prevention Program. The process involved the establishment of a local steering committee, 11 months of injury surveillance, a critical review of the evidence base, community consultations and assessment of community resources. There were 412 recorded injury cases during the surveillance period, with higher rates among men, manual workers, those aged 15–34 years, sport/ leisure activities and around the home and farm. Salient issues for residents included a lack of access to safety information and skills, particularly with regard to first aid and bush fire for isolated residents and rurally inexperienced new residents. While injury prevention was identified as an important issue for the community, the rapidly changing size and nature of the community and its infrastructure made this a particularly challenging issue. Challenges included limited availability of volunteers from key sectors, lack of formal data collection systems, difficulties in mobilising support for a broad issue like injury, limited communication networks and the negative impact of distance and role uncertainty on community ownership of the program. This case study illustrates the steps involved in an effective community-based needs assessment addressing injury prevention. Such an approach, if carried out systematically, will help ensure that the strategies and programs developed will be both appropriate and likely to obtain the support of the local community.     

Wallerian degeneration in a patient with Schilder disease: MR imaging demonstration

Wallerian degeneration in the corticospinal tract was demonstrated by magnetic resonance (MR) imaging in a patient with Schilder disease. The histochemical stages of myelin breakdown that allow its demonstration by MR imaging are reviewed.