Paramagnetic macrocyclic complexes as contrast agents for MR imaging: proton nuclear relaxation rate enhancement in aqueous solution and in rat tissues

Paramagnetic macrocyclic chelates show promise as magnetic resonance (MR) imaging contrast agents due to stability and relaxivity comparable to those of DTPA-type chelates. For the three copper and manganese macrocyclic complexes studied in aqueous solution, T1 and T2 relaxivities ranged from 0.14 to 5.88 mM-1sec-1 at 6.25 MHz. In rats, the intravenous administration of 16 mumol/kg of Mn(cyclam) caused the liver T1 relaxation rate to double at 15 minutes after injection. T1 measurements by pulsed MR imaging and manganese analyses on excised tissue showed that both relaxation rate (1/T1) and manganese content of liver and kidney increase linearly with the dosage of Mn(cyclam). The linear relationship between 1/T1 and manganese content can be considered an "in tissue" relaxivity plot for the agent. The resulting relaxivity is 54 mM-1sec-1 in liver, compared with 3.1 mM-1sec-1 in aqueous solution. Although this work is preliminary, the implication for medical MR imaging applications is that macrocyclic contrast agents can be effective at approximately one-tenth the current typical dose used for gadolinium DTPA.     

Measuring underuse of necessary care among elderly Medicare beneficiaries using inpatient and outpatient claims

CONTEXT: Continuing changes in the health care delivery system make it essential to monitor underuse of needed care, even for relatively well-insured populations. Traditional approaches to measuring underuse have relied on patient surveys and chart reviews, which are expensive, or simple single-condition claims-based indicators, which are not clinically convincing. OBJECTIVE: To develop a comprehensive, low-cost system for measuring underuse of necessary care among elderly patients using inpatient and outpatient Medicare claims. DESIGN: A 7-member, multispecialty expert physician panel was assembled and used a modified Delphi method to develop clinically detailed underuse indicators likely to be associated with avoidable poor outcomes for 15 common acute and chronic medical and surgical conditions. An automated system was developed to calculate the indicators using administrative data. SETTING AND SUBJECTS: A total of 345,253 randomly selected elderly US Medicare beneficiaries in 1994-1996. MAIN OUTCOME MEASURES: Proportion of beneficiaries receiving care, stratified by indicators of necessary care (n = 40, including 3 for preventive care), and avoidable outcomes (n = 6). RESULTS: For 16 of 40 necessary care indicators (including preventive care indicators), beneficiaries received the indicated care less than two thirds of the time. Of all indicators, African Americans scored significantly worse than whites on 16 and better on 2; residents of poverty areas scored significantly lower than nonresidents on 17 and higher on 1; residents of federally defined Health Professional Shortage Areas scored significantly lower than nonresidents on 16 and higher on none (P<.05 for all). CONCLUSIONS: This claims-based method detected substantial underuse problems likely to result in negative outcomes in elderly populations. Significantly more underuse problems were detected in populations known to receive less-than-average medical care. The method can serve as a reliable, valid tool for monitoring trends in underuse of needed care for older patients and for comparing care across health care plans and geographic areas based on claims data. JAMA. 2000;284:2325-2333.     

Wound healing activity of aqueous extract of Crotalaria verrucosa in Wistar albino rats

ObjectiveTo evaluate the wound healing effect of aqueous extract of Crotalaria verrucosa (C. verrucosa) in rats.MethodsThree wound models including incision, excision and dead space wounds were used in this study. The parameters studied were breaking strength in incision models, granulation tissue dry weight, breaking strength and hydroxyproline content in dead space wounds, percentage of wound contraction and period of epithelialization in excision wound model.ResultsTwo doses of the extract with and without dexamethasone showed significant increases in mean hydroxyproline, total protein content and dry weight of granulation tissue but it was higher with dose 800 mg/kg comparing with the control. The dexamethasone treated group showed a significant (P<0.001) reduction in the wound breaking strength when compared to control group in incision type of wound model. Coadministration of C. verrucosa with dexamethasone significantly (P<0.001) increased the breaking strength compared to the dexamethasone treated only group. In excision wound model, the percentage of the wound contraction was significantly (P<0.01) increased by two doses of test extract on all the days except the lower dose which exhibited only on 12 th, 16 th days of drug treatment and it also reversed the dexamethasone suppressed wound contraction. It significantly (P <0.001) reduced the time required for epithelialization and reversed the epithelialization delaying effect of dexamethasone (P<0.001).ConclusionsC. verrucosa was found to possess significant wound healing property. This was evident by decrease in the period of epithelialization, increase in the rate of wound contraction, skin breaking strength, and granulation tissue dry weight content. Hence C. verrucosa could be a good wound healing agent.