Ultraviolet irradiation of blood prevents transfusion-induced sensitization and marrow graft rejection in dogs

In a canine model using DLA-identical littermate pairs, we have shown that a regimen of three transfusions of donor blood given 24, 17, and 10 days before transplant uniformly leads to marrow graft rejection, presumably due to sensitization to minor (non-DLA) histocompatibility antigens. Untransfused dogs uniformly achieve sustained engraftment. In the present study, we investigated whether the exposure of blood to ultraviolet (UV) light (220-300 nm) prior to transfusion prevented sensitization of the recipient and allowed for successful marrow engraftment. Ten dogs were each given three pretransplant transfusions from the marrow donor. Each transfusion consisted of 50 mL of whole blood exposed in vitro to UV light for a total of 1.35 J/cm2. All ten dogs achieved engraftment. In contrast, all four dogs that had received sham-exposed transfusions rejected their grafts. In vitro studies revealed that although cell viability was not affected, leukocytes contained in UV-exposed blood were unable to function as stimulator cells in mixed leukocyte cultures or as accessory cells in mitogen- stimulated cultures. These data are consistent with the hypothesis that accessory cells are involved in transfusion-induced sensitization. We conclude that in vitro exposure of blood to UV light before transfusion prevents sensitization and allows for subsequent marrow engraftment.     

Effect of angioplasty-induced endothelial denudation compared with medial injury on regional coronary blood flow

To determine the effect of angioplasty-induced arterial injury on regional coronary blood flow, resting and postocclusion reactive hyperemic flows were measured in the left anterior descending (LAD) and circumflex (LCx) coronary arteries of 32 dogs after one of four interventions in the LAD with a balloon angioplasty catheter: group A, no injury; group B, endothelial denudation; group C, medial injury; group D, pretreatment with 325 mg of aspirin 2 hr before medial injury. Resting flows did not change in any group. In group C, hyperemic flow decreased in both the LAD and LCx by 15% to 20% (p less than .001) over 30 to 90 min, suggesting that a circulating substance changed coronary resistance. Histologic and ultrastructural studies of the LADs demonstrated an intact endothelial cell layer in group A, endothelial disruption with a few adherent platelets in group B, medial injury with a dense layer of adherent platelets in group C, and medial injury with a few adherent platelets in group D. Thus endothelial denudation results in relatively mild platelet deposition and no change in resting or hyperemic coronary blood flow. In contrast, medial injury results in relatively marked platelet deposition and a significant decrease in hyperemic flow, both of which are prevented by platelet inhibition with aspirin.     

Role of revascularization to treat chronic nonhealing fractures in ischemic limbs

The contribution of chronic limb ischemia to long-term nonunion of a lower extremity fracture was suggested in a single published case report from our group 13 years ago. We have since encountered three additional patients with nonunited lower extremity fractures occurring in limbs with arterial ischemia. In each of these four patients limb revascularization was undertaken in an effort to stimulate healing of the fracture. These patients had chronic (mean 6 months) nonunion of tibial (three) or femur (one) fractures associated with severe lower extremity ischemia (ankle/brachial index m = 0.33; range 0.24 to 0.5). All patients had histories of chronic lower extremity ischemia before the fracture (ischemic rest pain, 2; claudication, 2). All patients underwent angiography followed by lower extremity revascularization. Restoration of normal arterial supply to the fracture site was followed by healing of the fracture in all patients. To our knowledge, this represents the first reported series of patients undergoing elective limb revascularization to stimulate healing of the fracture. Widespread appreciation of this relationship by orthopedic surgeons may be of considerable clinical importance.     

Use of traditional health practices among Native Americans in a primary care setting

BACKGROUND: This study was undertaken to ascertain the extent that traditional health practices are used by urban American Indian/Alaska Native (AI/AN) primary care patients, to identify related patient characteristics, to determine associations with health status and functioning, and to describe attitudes about care received. METHODS: This study used a brief self-report survey of 869 adult AI/AN patients randomly sampled over a 14-month period from a comprehensive urban primary care program. Current medications were determined by follow-up medical record review. RESULTS: Seventy percent of urban AI/AN patients in primary care often used traditional health practices; use was strongly associated with cultural affiliation. In bivariate analyses, use was significantly associated with male gender, cultural affiliation, poor functional status, alcohol abuse, and trauma and, except for musculoskeletal pain, not with specific medical problems. The multiple logistic regression model for any use versus no use was significant (P < or =0.001). Being of male gender (P < or =0.001), having more than a high school education (P < or =0.05), visiting friends/relatives on a reservation (P < or =0.01), living the Native way of life (P < or =0.001) and not the white way (P < or =0.05), experiencing back pain (P < or =0.01), and having a physical injury inflicted by a family member (P < or =0.001) were predictive of use. CONCLUSIONS: The results in this clinical setting suggest that health care providers should anticipate use of traditional health practices among urban AI/AN patients. Use was predicted by important demographic, clinical, and cultural characteristics.     

Evaluating Community-Based Translational Interventions Using Historical Controls: Propensity Score vs. Disease Risk Score Approach

Many community-based translations of evidence-based interventions are designed as one-arm studies due to ethical and other considerations. Evaluating the impacts of such programs is challenging. Here, we examine the effectiveness of the lifestyle intervention implemented by the Special Diabetes Program for Indians Diabetes Prevention (SDPI-DP) demonstration project, a translational lifestyle intervention among American Indian and Alaska Native communities. Data from the landmark Diabetes Prevention Program placebo group was used as a historical control. We compared the use of propensity score (PS) and disease risk score (DRS) matching to adjust for potential confounder imbalance between groups. The unadjusted hazard ratio (HR) for diabetes risk was 0.35 for SDPI-DP lifestyle intervention vs. control. However, when relevant diabetes risk factors were considered, the adjusted HR estimates were attenuated toward 1, ranging from 0.56 (95% CI 0.44–0.71) to 0.69 (95% CI 0.56–0.96). The differences in estimated HRs using the PS and DRS approaches were relatively small but DRS matching resulted in more participants being matched and smaller standard errors of effect estimates. Carefully employed, publicly available randomized clinical trial data can be used as a historical control to evaluate the intervention effectiveness of one-arm community translational initiatives. It is critical to use a proper statistical method to balance the distributions of potential confounders between comparison groups in this kind of evaluations.

     

Predictors of performance on the MMSE and the DRS-2 among American Indian elders

Little is known about factors that predict older American Indians' performance on cognitive tests. This study examined 137 American Indian elders' performance on the MMSE and the Dementia Rating Scale-Second Edition (DRS-2). Multivariate regression identified younger age, more education, not receiving Supplemental Security Income, and frequent receipt of needed health care as predictors of better performance on the MMSE. Better performance on the DRS-2 was predicted by more education, boarding school attendance, not receiving Supplemental Security Income, and frequent receipt of needed health care. This study points to the importance of economic and educational factors on cognitive test performance among American Indian elders.     

Diagnostic reliability of telepsychiatry in American Indian veterans

OBJECTIVE: This study examined the reliability of the Structured Clinical Interview for DSM-III-R (SCID) in the administration of psychiatric assessments by real-time videoconferencing compared to face-to-face assessment within a rural American Indian community. METHOD: The SCID was administered to 53 male American Indian veterans who were randomly assigned over two separate occasions by different interviewers to face-to-face and real-time interactive videoconferencing within 2 weeks. Comparisons were made with prevalences, the McNemar test, and the kappa statistic. RESULTS: With the exception of past-year substance dependence and abuse/dependence combined, there were no significant differences between face-to-face and videoconference administration. The majority of kappas calculated (76%) indicated a good or fair level of agreement. Externalizing disorders tended to elicit greater concordance than internalizing disorders. CONCLUSIONS: Overall, SCID assessment by live interactive videoconferencing did not differ significantly from face-to-face assessment in this population. Videoconferencing is a viable vehicle for clinical and research purposes.