Generality-oriented optimization of enantioselective aminoxyl radical catalysis

Catalytic enantioselective methods that are generally applicable to a broad range of substrates are rare. We report a strategy for the oxidative desymmetrization of meso-diols predicated on a nontraditional catalyst optimization protocol by using a panel of screening substrates rather than a singular model substrate. Critical to this approach was rational modulation of a peptide sequence in the catalyst incorporating a distinct aminoxyl-based active residue. A general catalyst emerged, providing high selectivity in the delivery of enantioenriched lactones across a broad range of diols, while also achieving up to ~100,000 turnovers.

Kidneys at higher risk of discard: expanding the role of dual kidney transplantation

Half of the recovered expanded criteria donor (ECD) kidneys are discarded in the United States. A new kidney allocation system offers kidneys at higher risk of discard, Kidney Donor Profile Index (KDPI)>85%, to a wider geographic area to promote broader sharing and expedite utilization. Dual kidney transplantation (DKT) based on the KDPI is a potential option to streamline allocation of kidneys which otherwise would have been discarded. To assess the clinical utility of the KDPI in kidneys at higher risk of discard, we analyzed the OPTN/UNOS Registry that included the deceased donor kidneys recovered between 2002 and 2012. The primary outcomes were allograft survival, patient survival and discard rate based on different KDPI categories (<80%, 80-90% and >90%). Kidneys with KDPI>90% were associated with increased odds of discard (OR=1.99, 95% CI 1.74-2.29) compared to ones with KDPI<80%. DKTs of KDPI>90% were associated with lower overall allograft failure (HR=0.74, 95% CI 0.62-0.89) and better patient survival (HR=0.79, 95% CI 0.64-0.98) compared to single ECD kidneys with KDPI>90%. Kidneys at higher risk of discard may be offered in the up-front allocation system as a DKT. Further modeling and simulation studies are required to determine a reasonable KDPI cutoff percentile.

A case of human intramuscular adrenal gland transplantation as a cure for chronic adrenal insufficiency

Intramuscular endocrine gland transplantation has been well described as it pertains to parathyroid autotransplantation; however, transplantation of the adrenal gland is less well characterized. While adrenal autotransplantation in the setting of Cushing's disease has been described, intramuscular adrenal allotransplantation as a cure for adrenal insufficiency to our knowledge has not been previously carried out. Current treatment for adrenal insufficiency leaves patients without diurnal variation in cortisol release and susceptible to the detrimental effects of chronic hypercortisolism. We describe here the case of a 5-year-old girl with renal failure who had adrenal insufficiency following fulminant meningococcemia that led to requirements for both stress-dose steroid and mineralocorticoid replacement. Ten months after the onset of her disease, she received a simultaneous renal and adrenal gland transplant from her mother. The adrenal gland allograft was morselized into 1 mm(3) segments and implanted into three 2 cm pockets created in her rectus abdominis muscle. Three years after surgery, her allograft remains fully functional, responding well to adrenocorticotropin hormone stimulation and the patient does not require any steroid or mineral-corticoid supplementation. We believe this case represents the first description of successful functional intramuscular adrenal allograft transplantation with long-term follow up as a cure for adrenal insufficiency.

Survival outcomes following liver transplantation (SOFT) score: a novel method to predict patient survival following liver transplantation

It is critical to balance waitlist mortality against posttransplant mortality. Our objective was to devise a scoring system that predicts recipient survival at 3 months following liver transplantation to complement MELD-predicted waitlist mortality. Univariate and multivariate analysis on 21,673 liver transplant recipients identified independent recipient and donor risk factors for posttransplant mortality. A retrospective analysis conducted on 30,321 waitlisted candidates reevaluated the predictive ability of the Model for End-Stage Liver Disease (MELD) score. We identified 13 recipient factors, 4 donor factors and 2 operative factors (warm and cold ischemia) as significant predictors of recipient mortality following liver transplantation at 3 months. The Survival Outcomes Following Liver Transplant (SOFT) Score utilized 18 risk factors (excluding warm ischemia) to successfully predict 3-month recipient survival following liver transplantation. This analysis represents a study of waitlisted candidates and transplant recipients of liver allografts after the MELD score was implemented. Unlike MELD, the SOFT score can accurately predict 3-month survival following liver transplantation. The most significant risk factors were previous transplantation and life support pretransplant. The SOFT score can help clinicians determine in real time which candidates should be transplanted with which allografts. Combined with MELD, SOFT can better quantify survival benefit for individual transplant procedures.

Validation of the scoring system for standardization of the pancreatic donor for islet isolation as used in a new islet isolation center

BACKGROUND

The aim of this study was to evaluate the effectiveness of the Edmonton Donor Scoring System for use in our much less active islet center. Because the ability to recognize an appropriate donor may help to achieve consistent and predictable success of pancreatic islet isolation, it should lead to increased effectiveness and lower cost.

MATERIAL AND METHODS

Charts of 36 consecutive pancreas donors were reviewed to assess the donor points (DP). DP ranged from 0 to 100 based on donor age, body mass index, cause of death, social and medical history, hospital stay, vasopressor dosages, laboratory tests, cold ischemia time and procurement team, as well as pancreas size, consistency, fat content, damage, and quality of procurement and packing.

RESULTS

Successful isolation was achieved in 39% of donors (14 of 36), a value similar to that achieved in Edmonton (40%). We used the optimal cutoff value (DP = 79) proposed by the Edmonton group. Sensitivity, specificity, positive predictive value, negative predictive value, and accuracy were 66%, 75%, 57%, 82% and 72%, respectively. Successful islet isolation from poor or marginal donors (DP < 49.5 and 50 to 59.5) was 0% and 28.6% respectively; it was 63% and 100% in optimal donors (DP = 80 to 89.5 and 90 to 100). We concluded that islet isolation success correlated with the previously proposed donor scoring system.

CONCLUSIONS

The Donor Scoring System can be successfully implemented regardless of the level of activity of an experienced isolation center. This system permits identification of a suitable donor prior to organ processing. It may guide a center's donor selection strategy based on its goals and its budget.

Microscopic Intrarenal Particles After Pulsatile Machine Preservation Do Not Adversely Affect Outcomes After Renal Transplantation

INTRODUCTION

Our center has recently observed foreign carbohydrate-appearing particles (FP) on transplant postreperfusion biopsy specimens: (PRBx).

METHODS

To further characterize FPs, we reviewed all renal transplant RBx (30-45 minutes) performed between September 1, 2004 and December 3, 2005. Donor, preservation, and outcome variables were collected among patients with FP.

RESULTS

A total of 135 PRBx were performed (45 deceased donors [DD] and 90 live donors [LD]). Fifteen PRBx demonstrated FP. All 15 cases were DD kidneys that underwent machine perfusion (MP) on the Waters RM3 (Waters Medical Systems, Rochester, Minn, United States) with Belzer MP solution (Trans Med, Elk River, Minn, United States). Donor age was 39.8 +/- 15.7 years. Terminal creatinine level was 1.45 +/- 0.8 mg/dL. Two of 15 were flushed in situ with HTK solution (no starch). Cold ischemia time was 28.8 +/- 9.1 hours with 14.3 +/- 5.1 hours of MP. In 13 of 15 patients, perfusion parameters were excellent (flow > 100 mL; resistance < .35). CHARACTERISTICS OF FP: Particles were 10-30 mu and globular in shape. FP were not visible on hematoxylin and eosin stain, but stained strongly periodic acid-Schiff-(PAS) positive and were refractile under polarized light. FP were seen segmentally within glomerular capillaries in all cases and in peritubular capillaries in 3. In 11 of the 15 cases with FP, focal glomerular fibrin thrombi or intracapillary neutrophil margination was seen. Ten of 15 patients with FP had a biopsy within the first week with no identifiable FP.

OUTCOMES

Recipient age was 45.3 +/- 11.6 years. Eight patients (53.3%) had delayed graft function. Biopsy-proven rejection occurred in 3 patients (20%). Three-month creatinine level was 1.59 +/- 0.35 mg/dL. One graft was lost to early thrombosis in a patient with a hypercoagulable state and 1 patient died of sepsis at 2 months. All remaining 13 patients are alive with excellent graft function at a median follow-up of 6.7 months (range, 3-17 months).

CONCLUSIONS

Microscopic intrarenal particles may be seen on DD kidney PRBx after MP. These FPs likely originate from surgical gloves. FPs are too small to be captured by standard filters but clear spontaneously and do not have deleterious effects on renal function or outcomes.

Effect of streptavidin on cardiac allograft prolongation is due to host T-Cell suppression

AIM

The aim of this study was to evaluate the effectiveness of streptavidin immunomodulation in the high-responder WF-to-Lewis combination.

METHODS/RESULTS

We examined the effects of streptavidin on the proliferative response of T cells in coculture studies. Two to 200 microg/mL streptavidin significantly (P < .001) suppressed the proliferation of Lewis T cells to WF by 76%-83% compared with untreated responders. Next, we studied the survival of WF cardiac allografts in Lewis recipients pretreated with streptavidin. A 5-day course of peritransplantation recipient treatment with streptavidin doses of 8, 12, 20, 40, and 60 mg/kg combined with single dose of 0.5 mL antilymphocyte serum (ALS) significantly (P < .001) prolonged cardiac allograft survival from MST of 7 +/- 0.5 and 8 +/- 0.5 days in naive and ALS-treated controls to 15 +/- 1, 20 +/- 3, 16 +/- 3, 17 +/- 3, and 23 +/- 2 days, respectively. In contrast, posttransplantation administration of 80 mg/kg streptavidin resulted in animal death, suggesting toxicity of this dose. Additionally, 10 mg/kg or 20 mg/kg streptavidin administration for 10 consecutive days resulted in significant graft prolongation (MST of 18 +/- 1 and 21 +/- 1 days, respectively; P < .001).

CONCLUSION

Although peritransplantation streptavidin treatment is effective in prolonging rat cardiac allografts in the high-responder WF-to-Lewis combination, it does not induce permanent graft survival as observed in the low-responder combination of Lewis-to-ACI. Our finding of in vitro immunomodulatory effect of streptavidin on T-cell proliferation suggests that its in vivo effect is partly due to prevention of T-cell activation following antigen exposure.

Two-Layer Method in Short-Term Pancreas Preservation for Successful Islet Isolation

BACKGROUND

We sought to determine whether the two-layer method (TLM) offers advantages over UW storage solution for locally procured pancreata with cold ischemia time of <8 hours for successful islet isolation.

METHODS

From October 2003 through February 2005, 22 human pancreata were procured locally from cadaveric donors and preserved using UW solution (n = 11) or TLM (n = 11).

RESULTS

Donor characteristics were similar in the two groups, with no statistical difference. Cold ischemia time was 4.5 +/- 0.6 (2.5 to 8) hours in the UW and 5.1 +/- 0.5 (3 to 8) hours in TLM group (P > .05). Organs preserved with TLM were exposed to PFC for 4 +/- 0.5 (2 to 7.5) hours. After TLM preservation, 8 of 11 (72%) pancreata yielded >300,000 IEQ pancreatic islets, which met all criteria for clinical transplantation; after UW cold storage, only 3 of 11 isolations were equally successful (27%) (P < .05). Mean IEQ was higher in the TLM than in the UW group: 349,000 +/- 37,000 vs 277,800 +/- 34,000; IEQ/g was also higher at 5100 +/- 760 vs 3000 +/- 570, respectively (P < .05). Islet quality, characterized by purity, viability, and insulin SI, did not differ statistically in the two groups: 67 +/- 4 vs 74 +/- 4%, 87 +/- 2 vs 83 +/- 4%, and 4 +/- 0.7 vs 4.8 +/- 1, respectively (P > .05).

CONCLUSIONS

The Two Layer Method for locally procured human pancreata with cold ischemia time lower than 8 hours offers significant advantage over UW cold storage increasing the pancreatic islet isolation yield and the isolation success rate.

Infectious tolerance mediated by CD8+ T-Suppresor Cells After UV-B–irradiated donor-specific transfusion and rat heart transplantation

AIMS

CD8+CD28- human T-suppressor cells (Ts), which can be generated in vitro, act directly on APC rendering them tolerogenic to unprimed and primed CD4+ T cells. The aim of this study was to investigate the possibility that CD8+ T cells mediate the induction of tolerance in a heart transplantation model in rodents.

MATERIALS AND METHODS

Blood from Lewis rats was UV-B-irradiated and transfused into ACI recipients on days -21, -14, and -7 before heart allograft transplantation on day 0. CD4(+) and CD8(+) T cells were positively selected from ACI rats, which had tolerated Lewis heart allografts for more than 100 days and were adoptively transferred to naive ACI rats pretreated (day -1) with gamma irradiation. These ACI rats underwent transplantation with Lewis hearts 24 hours after adoptive transfer of putative T-suppressor cells.

RESULTS

Adoptive transfer of CD8(+) T cells from tolerant ACI to naive ACI rats significantly prolonged Lewis heart mean allograft survival time (MST +/- SD) to 69 +/- 13 days as compared with 15 +/- 1 and 14 +/- 1 days in animals adoptively transferred with CD4+ T cells or untreated controls, respectively (P < .001). Similarly, adoptive transfer of CD8(+) T cells from secondary ACI recipients to naive syngeneic animals also significantly prolonged survival of heart allografts to MST +/- SD of 72 +/- 4 for CD8(+) and 15 +/- 4 days for CD4(+) T cells (P < .001).

CONCLUSIONS

These data demonstrate that allogeneic tolerance induced in ACI recipients by treatment with UV-B-irradiated blood from Lewis donors is mediated by CD8+ T-suppressor cells.

Ethical issues in living renal donation

The widespread success of living renal transplantation has given the medical community both the opportunity and the responsibility of establishing social and ethical guidelines for the protection of donors and the treatment of recipients. While the prospects of treating more patients with organ transplant is exciting, the demand still far outpaces the supply. It is the responsibility of the transplant community and individual transplant centers to maintain a high level of integrity and ethical practice so that living renal transplantation can continue to be a viable and effective treatment for renal failure.

Role of reentry of in vivo alloMHC peptide-activated T cells into the adult thymus in acquired systemic tolerance

BACKGROUND

T cell recognition of alloMHC peptide presented by self dendritic cells via the indirect pathway of allorecognition in the thymus induces T cell tolerance. Most recently we have shown that the i.v. administration of immunodominant Wistar Furth MHC class I (RT1.Au) peptide 5- (P5) pulsed myeloid or lymphoid dendritic cells induces operational tolerance to a fully MHC-mismatched cardiac allograft. This finding led us to hypothesize that circulation of peripheral P5-activated T cells to the thymus plays an important role in the induction of acquired tolerance.

METHODS

We used the adoptive transfer of 111Indium-oxine- (111In-oxine) labeled P5-pulsed syngeneic dendritic cells and in vivo P5-activated syngeneic T cells to study the role of their circulation to the thymus in the induction of transplantation tolerance.

RESULTS

Intravenously administered 111In-oxine-labeled naïve DC actively migrated to and localized in the liver and spleen but did not enter the lymph nodes, bone marrow, and thymus. In vitro peptide-pulsed dendritic cells had a similar pattern of tissue localization except for a modest number of myeloid but not lymphoid DC entering the thymus. The demonstration that adoptive transfer of in vivo peptide-primed T cells induces permanent graft survival in antilymphocyte serum transiently immunosuppressed syngeneic secondary hosts led us to examine the traffic of in vivo activated T cells. Whereas naïve syngeneic T cells preferentially homed to the peripheral lymphoid organs, they did not reenter the thymus. In contrast, in vivo peptide-activated peripheral T cells migrated to and accumulated in the thymus, thus confirming that reentry of T cells to the thymus is restricted to in vivo activated T cells. Although antilymphocyte serum immunosuppression significantly reduced circulation of primed T cells to the thymus, it did not completely abolish it, as seen with gamma-irradiated primed T cells.

CONCLUSION

These findings provide the first formal evidence directly linking reentry of in vivo alloMHC peptide-activated T cells to the thymus with the induction and possibly maintenance of acquired antigen-specific tolerance. Our results suggest that the thymus is open to a two-way traffic with the periphery and may function as a repository of immunological memory.

Induction of transplant tolerance with immunodominant allopeptide-pulsed host lymphoid and myeloid dendritic cells

We have studied the effects of adoptive transfer of host thymic dendritic cells pulsed with immunodominant WF Class I peptide 5 (residues 93-109) on cardiac allograft survival in the WF-to-ACI rat combination. Our results showed that, whereas intrathymic inoculation of WF peptide 5-pulsed ACI thymic dendritic cells alone on day -7 did not prolong graft survival, similar treatment combined with 0.5 mL antilymphocyte serum (ALS) led to 100% permanent acceptance (> 200d) of donor-specific cardiac allografts. Extension of our study to systemic administration of peptide 5-pulsed host thymic dendritic cells confirmed that intravenous injection of peptide 5-pulsed self thymic dendritic cells combined with ALS transient immunosuppression resulted in 100% permanent donor-specific graft survival (> 200d). These results were reproducible in a clinically relevant model using intravenous injection of peptide-pulsed host myeloid dendritic cells. In contrast, thymectomy prior to adoptive transfer of peptide-pulsed host dendritic cells resulted in acute graft rejection at times equivalent to rejection in thymectomized controls. The long-term unresponsive recipients challenged with second-set grafts accepted permanently (> 100d) donor-type (WF) but not third party (Lewis) cardiac allografts. This study suggests that intravenous administration of genetically engineered dendritic cells expressing donor MHC molecules has the potential of inducing transplant tolerance.

Indirect allorecognition in acquired thymic tolerance: induction of donor-specific permanent acceptance of rat islets by adoptive transfer of allopeptide-pulsed host myeloid and thymic dendritic cells

Pancreatic islet transplantation remains a promising approach to the treatment of type 1 diabetes. Unfortunately, graft failure continues to occur because of immunologic rejection, despite the use of potent immunosuppressive agents. It is therefore reasoned that induction of peripheral tolerance by the use of self-dendritic cells (DCs) as a vehicle to deliver specific target antigens to self-T-cells without ex vivo manipulation of the recipient is an attractive strategy in the treatment of type 1 diabetes. The finding that intrathymic inoculation of an immunodominant WF major histocompatibility complex (MHC) Class I (RT1.A(u)) peptide five (P5) or P5-pulsed host myeloid DCs induces acquired thymic tolerance raises the possibility that adoptive transfer of allopeptide-primed host myeloid or lymphoid DCs might induce transplant tolerance. To address this hypothesis, we studied the effects of intravenous transfer of in vitro P5-pulsed syngeneic myeloid DCs or in vivo P5-primed syngeneic lymphoid (thymic) DCs on islet survival in the WF-to-ACI rat combination. In vivo primed thymic DCs isolated from ACI rats given intrathymic inoculation of P5 for 2 days were capable of in vitro restimulation of in vivo P5-primed T-cells (memory cells). In the first series of studies, we showed that intravenous-like intrathymic-inoculation of in vitro P5-pulsed host myeloid DCs induced donor-specific permanent acceptance of islets in recipients transiently immunosuppressed with antilymphocyte serum (ALS). We next examined whether thymic DCs isolated from animals that had been previously intrathymically inoculated with P5 could induce T-cell tolerance. The results showed that intravenous adoptive transfer of in vivo P5-primed thymic DCs led to donor-specific permanent acceptance of islets in recipients transiently immunosuppressed with ALS. This finding suggested that the thymic DCs take up and present P5 to developing T-cells to induce T-cell tolerance, thus providing evidence of a direct link between indirect allorecognition and acquired thymic tolerance. The second series of studies examined the mechanisms involved in this model by exploring whether in vivo generation of peptide-specific alloreactive peripheral T-cells by intravenous inoculation of P5-pulsed self-DCs was responsible for the induction of T-cell tolerance. Intrathymic inoculation of splenic T-cells obtained from syngeneic ACI rats primed with intravenous injection of P5-pulsed DCs with a high in vitro proliferative response to P5 in the context of self-MHC induced donor-specific permanent acceptance of islets from WF donors. In addition, the clinically relevant model of intravenous injection of P5-activated T-cells combined with transient ALS immunosuppression similarly induced transplant tolerance, which was then abrogated by thymectomy of the recipient before intravenous injection of the activated T-cells. These data raise the possibility that circulation of peptide-activated T-cells to the host thymus plays a role in the induction and possibly the maintenance of T-cell tolerance in this model. Our findings suggest that intravenous administration of genetically engineered host DCs expressing alloMHC peptides might have therapeutic potential in clinical islet transplantation for the treatment of autoimmune diabetes.

Mechanisms of acquired thymic tolerance: induction of transplant tolerance by adoptive transfer of in vivo allomhc peptide activated syngeneic T cells

BACKGROUND

Our most recent observation that i.v. injection of Wistar-Furth (WF) major histocompatibility complex Class I peptide 5 (P5)-pulsed self-myeloid or lymphoid dendritic cells (DC) induces transplantation tolerance suggests that adoptive transfer of in vivo allopeptide-primed host T cells might induce acquired tolerance through their interaction with thymic DC.

METHODS

To examine this hypothesis, host myeloid DC cultured in rat granulocyte/macrophage colony stimulating factor and interleukin 4 were pulsed in vitro with P5 and injected intravenously into syngeneic ACI rats. The T cells primed to P5 via the indirect pathway of allorecognition were harvested 7 days later and administered by either intravenously or intrathymically into syngeneic ACI recipients of WF cardiac allografts.

RESULTS

Syngeneic T cells obtained from the spleen of P5-primed rats had a high mixed lymphocyte reaction proliferative response to P5 presented by self-DC. I.v. administration of 2x107 P5-primed alloreactive purified host splenic T cells alone on day -7 significantly (P<0.001) prolonged cardiac allograft survival from 10.5+/-1.0 days to 18.6+/-1.8 days in the WF-to-ACI rat combination. I.v. injection of P5-activated host T cells combined with 0.5 ml antilymphocyte serum (ALS)-transient immunosuppression on day -7 led to 100% donor-specific permanent graft survival (>200 days). Thymectomy before i.v. injection of P5-activated syngeneic T cells led to acute graft rejection, suggesting that the homing of in vivo activated T cells to the host thymus might play a role in the induction of tolerance. To further define the role of the recipient thymus in this model, we examined the effects of intrathymic (i.t.) injection of P5-primed alloreactive T cells on graft survival and found that i.t. administration of the P5-primed T cells on day -7 alone significantly prolonged graft survival (15.0+/-0.7 days) and when combined with 0.5 ml ALS led to donor-specific permanent graft survival. The long-term unresponsive recipients permanently (>100 days) accepted second-set donor-specific cardiac allografts but not third-party (Lewis) grafts.

CONCLUSIONS

These findings demonstrate that the adoptive transfer of splenic T cells primed to an indirectly presented donor peptide induces transplantation tolerance in a transiently immunosuppressed secondary syngeneic recipient. Our data suggest that the interaction of thymic DC with activated peripheral T cells induces alloantigen (Ag)-specific T-cell tolerance by either inactivation or deletion of alloreactive T cells in the thymus. This observation provides the first formal evidence that the interaction between thymic DC and activated peripheral T cells that continuously circulate through the thymus plays an important role in the induction and maintenance of Ag-specific tolerance.

Immunologic considerations in composite tissue transplantation: overview

Successful clinical transplantation of the upper extremity has been performed in several centers. In contrast with the recipients of other immediately vascularized organ allografts, the candidate for upper extremity transplantation has been, at least during the initial effort, a healthy patient. Although it is clear that composite tissue transplantation (CTA) is a form of allografting that behaves in many ways similarly to immediately vascularized organ allografts, the issue of developing immunologic understanding of such new allografts, awaits greater clinical experience. A summary of the immunosuppressive management of the patients who received hand allografts, with a view to explore the immunologic advantages and disadvantages as well as graft toxicity of the commonly used agents, is reported. This brief overview of the immunologic considerations in CTA is presented with the purpose of summarizing the main issues that contribute to the ultimate goal of achieving tolerance. These considerations include (1) the recipients before transplantation, (2) the donors including possible pretreatment, (3) immunosuppression for induction, maintenance, and treatment of acute rejection and its diagnosis, and (4) future potential for tolerance induction.

Job satisfaction among nursing staff in a military health care facility

Job satisfaction in the workplace affects absenteeism, turnover, and performance. We conducted a cross-sectional study of 201 nursing personnel to assess satisfaction among nursing staff at a military hospital in the southwestern United States. Participants completed a self-administered survey in which they rated professional status, autonomy, pay, organizational policies, task requirements, and interaction by importance and satisfaction. Autonomy, professional status, and pay were the most important factors and organizational policies was the least important factor. Military staff were slightly more satisfied with staff interactions than civilian staff. Nursing personnel working in specialty care units were significantly more satisfied with interactions and professional status, but they valued organizational policies less than those working in general units. Professionals were significantly more satisfied with pay and autonomy, whereas nonprofessionals were more satisfied with task requirements and professional status.

Pension decisions in a changing economy: gender, structure, and choice

OBJECTIVES

As responsibility for financial security in retirement becomes more individualized, understanding the distribution and determinants of savings behavior grows in importance. Employed men and women often gain access to their pension assets when they change jobs. In this study gender differences in pre-retirement access to and disposition of accumulated pension assets are examined.

METHODS

The authors used data from the Health and Retirement Study to model pension participation, disposition of pension assets, and use of cash settlements derived from a pension plan in a previous job. Logit models provided estimates of gender differences in access to pensions and the preservation of pension funds for retirement.

RESULTS

Women were less likely to have participated in employer-sponsored pension plans; more likely to cash out accumulated pension assets when they changed jobs; and, when job changes occurred at relatively young ages, equally likely to spend the settlement. However, by their late 40s, women were more likely to save the settlement, a net gender difference that increased with age at which the settlement was received.

DISCUSSION

The structure of employment compensation continues to place women at a disadvantage. Gender differences in earnings and fringe benefits not only affect current financial status, but also cast a shadow over future financial security. Although the gender gap in pension coverage has been reduced, women with pensions have access to lower benefits and less in accumulated assets. As these continuing deficits are addressed, enhancing women's tendency to save pension assets for retirement can help them build financial security.

Administration of equine anti-thymocyte globulin via peripheral vein in renal transplant recipients

BACKGROUND

Anti-thymocyte globulin (ATG) is used frequently as induction therapy in renal transplant recipients. It has been standard practice that the various polyclonal anti-lymphocyte preparations be administered via central line, vascular shunt, or arteriovenous fistula to avoid thrombophlebitis.

METHODS

We have safely administered equine ATG (Atgam) via peripheral veins since 1978. We now retrospectively review recent experience with 83 patients transplanted between 1993 and 1998 who received Atgam induction via peripheral vein. Heparin 1000 U and Solucortef 20 mg were added to the infusion. Acetaminophen and diphenhydramine were given before infusion.

RESULTS

Only two of 83 patients developed mild edema/erythema at or around the i.v. site. These reactions responded promptly to local management with warm soaks. No phlebitis or symptomatic venous thrombosis occurred in any patients.

CONCLUSIONS

Equine ATG can be safely administered via peripheral vein infusion. Its use does not require continued hospitalization or placement of a central line. Peripheral vein infusion is safe, convenient, and economical.

Major histocompatibility complex class I peptide-pulsed host dendritic cells induce antigen-specific acquired thymic tolerance to islet cells

BACKGROUND

As T-cell receptor-major histocompatibility complex (MHC) class I/self peptide interaction regulates T-cell development in the thymus, we reasoned that presentation of peptides by self dendritic cells (DC) to developing T cells in the thymus might induce acquired thymic tolerance. This hypothesis is based on the finding that intrathymic injection of allopeptides in the adult animal induces acquired tolerance. To examine this hypothesis, we studied the effects of intrathymic (IT) injection of a single immunodominant Wistar-Furth (WF) MHC class I (RT1.Au) peptide-pulsed host DC on islet allograft survival in the WF-to-ACI rat combination.

METHODS

Bone marrow-derived ACI DC expressing MHC class I and II, OX62, and ED2 present allopeptides to naive and specifically peptide-primed syngeneic T cells in mixed lymphocyte reaction. Host DC pulsed with RT1.Au peptide 5 (residues 93-109) were injected into the thymus of streptozotocin-induced diabetic ACI that were transplanted 7 days later with donor-type (WF) or third-party (Brown Norway [BN]) islets.

RESULTS

Whereas IT injection of 300 microg of peptide 5 alone led to normoglycemia and permanent islet survival in three of six diabetic ACI recipients, similar treatment combined with simultaneous intraperitoneal injection of 0.5 ml of anti-lymphocyte serum (ALS) on day -7 led to 100% permanent islet allograft survival (>200 days) compared to a mean survival time of 15.0+/-2.3 days in controls treated with ALS alone. In contrast, similarly prepared animals rejected the third-party (BN) islets in an acute fashion. To address the question of indirect allorecognition in acquired thymic tolerance, we examined the effect of peptide-pulsed host DC on graft survival. Whereas IT injection of peptide-pulsed host DC alone resulted in permanent islet survival in two of five animals, IT injection of peptide-pulsed host DC combined with 0.5 ml of ALS induced 100% donor-specific permanent islet allograft survival in the WF-to-ACI rat combination. These results suggest that thymic DC take up, process, and present the administered peptide to the developing T cells by the indirect allorecognition pathway in the induction of acquired thymic tolerance.

CONCLUSION

We have demonstrated a novel approach to inducing transplant tolerance to islet allografts with IT injection of allopeptide-pulsed host DC. This finding suggests that immunization strategies using DC expressing MHC allopeptides or peptide analogue might be potentially useful in the treatment of autoimmune diabetes mellitus.

Influence of lamotrigine on progression of early Huntington disease: a randomized clinical trial

OBJECTIVE

To assess the efficacy of lamotrigine, a novel antiepileptic drug that inhibits glutamate release, to retard disease progression in Huntington disease (HD).

BACKGROUND

Excitatory amino acids may cause selective neuronal death in HD, and lamotrigine may inhibit glutamate release in vivo.

METHODS

A double-blinded, placebo-controlled study was conducted of 64 patients with motor signs of less than 5 years' duration who were randomly assigned to either placebo or lamotrigine and assessed at 0 (baseline), 12, 24, and 30 months. The primary response variable was total functional capacity (TFC) score. Secondary response variables included the quantified neurological examination and a set of cognitive and motor tests. Repeated fluorodeoxyglucose measurements of regional cerebral metabolism using PET also were included.

RESULTS

Fifty-five patients (28 on lamotrigine, 27 on placebo) completed the study. Neither the primary response variable nor any of the secondary response variables differed significantly between the treatment groups. Both the lamotrigine and the placebo group deteriorated significantly on the TFC, in the lamotrigine group by 1.89 and the placebo group by 2.11 points. No effect of CAG size on the rate of deterioration could be detected.

CONCLUSIONS

There was no clear evidence that lamotrigine retarded the progression of early Huntington disease over a period of 30 months. However, more patients on lamotrigine reported symptomatic improvement (53.6 versus 14.8%; p = 0.006), and a trend toward decreased chorea was evident in the treated group (p = 0.08). The study also identified various indices of disease progression, including motor tests and PET studies, that were sensitive to deterioration over time.

Monitoring of rat islet allografts with dithizone after induction of donor specific transplant tolerance by intrathymic administration of soluble alloantigens

Transplantation of whole pancreas or pancreatic islets remains a promising approach to treatment of diabetes mellitus. Since there is no efficient method presently known for in vivo detection of pancreatic islet rejection, we have utilized dithizone [DTZ] to monitor the survival of transplanted islet allografts following the induction of tolerance by a new strategy of deliberate introduction of donor antigens into the adult thymus. In this study, we examined the morphology of islet allografts in vivo and in vitro following pretreatment with intrathymic (IT) inoculation of 2 mg soluble Ag obtained from 3M KCl extracts of resting T-cells with or without ALS immunosuppression in the WF-to-Lewis combination. Fresh isolated rat islets stained pink 3-5 minutes following exposure to medium containing 0.12 mM DTZ solution in DMSO. Intravenous (i.v.) injection of DTZ solution into unmodified recipients of islet allografts that had rejected their grafts showed massive degranulation of islets which did not stain pink with DTZ. This was confirmed by microscopic finding of fibrosis and lymphocytic infiltration. In contrast, i.v. injection of DTZ solution into long-term recipients of islet allografts at 50, 100, and 150 days after transplantation showed viable islet cells which stained crimson red with DTZ and the findings were confirmed with microscopic sections. This study demonstrates that DTZ is an effective means of in vivo and in vitro identification of transplanted pancreatic islets and suggests that this strategy may have potential clinical application in the diagnosis of the pancreatic islet rejection.

The effect of clinical and biochemical donor parameters on pancreatic islet isolation yield from cadaveric organ donors

The recovery of pancreatic islet cells from cadaveric donors for allotransplantation may depend on the functional condition of the pancreas of the donor prior to organ harvesting. We examined donor hemodynamic and biochemical parameters and their effects on the subsequent yield of islet cells after harvesting. All pancreata were flushed and preserved in University of Wisconsin (UW) solution and digested using automated method within 8 hours. In the first analysis, digestions were divided into high-yield (> 2000 IEQ/g pancreas), and low-yield (< 2000 IEQ/g) groups and donor variables were averaged for each group. Donors whose pancreata yielded > 2000 IEQ/g received significantly greater amounts of Dopamine (14.43 micrograms/kg/min vs 9.35 mg/kg/min, p = 0.05). The daily urine output between groups was also significantly different. Maximum systolic blood pressure (SBP), minimum systolic blood pressure, use of vasopressin, length of hospitalization, and maximum base deficit were compared between the two groups. Less severe hypoglycemia (lowest blood glucose 143 mg/dL vs 107 mg/dL, p = 0.02) and lower amylase levels (36.2 U vs 80.7, p = 0.07 were noted in the high-yield group. A trend towards higher islet yields was associated with lowest hourly urine output > 60 (2040 IEQ/g vs 1649 IEQ/g p = 0.09), maximum SBP > 200 (2097 vs 1673, p = 0.07, and surprisingly, lowest SBP below 80 (2013 vs 1742, p < 0.1). Amount of fluids administered prior to procurement had no influence on islet yield. In conclusion, hemodynamic variables such as urine output, systolic blood pressure, and degree of pressor support were modestly associated with successful islet isolation. The preliminary data suggest that better multifactor donor analysis is imperative for standardization and monitoring of multiorgan donors. The association of higher blood glucose levels with successful isolation may also be related to resuscitation with dextrose-containing fluids.

Persistent allopeptide reactivity and epitope spreading in chronic rejection of organ allografts

The role of the indirect allorecognition pathway in acute allograft rejection has been documented both in organ recipients and in experimental models. However, it is unknown whether self-restricted recognition of donor alloantigens also contributes to chronic allograft rejection. The aim of this study was to determine the relationship between allopeptide reactivity, epitope spreading, and chronic rejection. Using synthetic peptides corresponding to the hypervariable region of 32 HLA-DR alleles, we have followed the specificity of self-restricted T cell alloresponses to the donor in a population of 34 heart allograft recipients. T cells from sequential samples of blood collected from the patients up to 36 mo after transplantation were studied in limiting dilution analysis for allopeptide reactivity. The incidence of coronary artery vasculopathy (CAV) was significantly higher in patients who displayed persistent alloreactivity late after transplantation than in patients who showed no alloreactivity after the first 6 mo after transplantation. Both intra- and intermolecular spreading of epitopes was observed with an increased frequency in patients developing CAV in less than 2 yr, compared with patients without CAV; this suggests that diversification of the immune response against the graft contributes to chronic rejection. These data provide a strategy for identifying patients at risk of developing CAV and a rationale for therapeutic intervention aimed to prevent the progression of the rejection process.

Mitochondrial activity after cold preservation of pancreatic islet cells treated with pefloxacin (PFX)

Mitochondrial energetic and oxidative dysfunctions caused by free radical production trigger release of proinflammatory cytokines involved in organ rejection. The aim of this study was to investigate the role of a fluoroquinolone drug, pefloxacin (PFX) and those of various cold preservation solutions on pancreatic beta cell viability. Our data clearly demonstrate that islet cell viability, as determined by glucose-stimulated insulin secretion, is directly correlated with reduced expression of microsomal cytochrome P-450IIIA. Moreover, IL-2, a known mediator of apoptosis was found to be downregulated, whereas TNF-alpha had been upregulated for the first 18 hours after pefloxacin administration. These results demonstrate that pefloxacin downregulates the expression of cytochrome P-450IIIA isozyme and regulates the production of TNF-alpha and IL-2. Thus, we postulate that the presence of pefloxacin in the pancreatic islet cells before organ preservation facilitates increased cell viability.

New strategies for early diagnosis of heart allograft rejection

BACKGROUND

Allograft rejection is mediated by T cells that recognize allogeneic major histocompatibility complex (MHC) molecules via the direct and indirect pathway. The direct pathway involves T cells that react against MHC/peptide complexes expressed on the surface of donor antigen-presenting cells (APCs). In contrast, T cells involved in the indirect pathway recognize peptides derived from processing and presentation of allogeneic MHC molecules by self (recipient) APCs. To explore the relative contribution of these two pathways to rejection, we have evaluated the response of peripheral blood T cells from 50 heart transplant recipients against donor APCs (direct recognition) and against self APCs pulsed with synthetic peptides corresponding to the hypervariable region of the mismatched HLA-DR antigens of the donor (indirect recognition).

METHODS

T cell reactivity against donor APCs was quantitated by measuring the expression of CD69 on allostimulated CD3+ LDA1+ cells. Reactivity to synthetic allopeptides was determined in limited dilution assays.

RESULTS

Serial studies of the kinetics of direct and indirect recognition showed that both pathways contribute to early acute rejection episodes. Primary rejection was accompanied invariably by indirect recognition of a dominant allopeptide. Intermolecular spreading of T cell epitopes was observed during recurrent rejections. Enhanced recognition of donor alloantigens via the direct pathway was found predominantly during early rejection episodes. A single form of allorecognition was shown to occur in some rejection episodes.

CONCLUSIONS

Monitoring of the direct and indirect pathway of allorecognition provides a reliable method for prediction and differential diagnosis of acute rejection of heart allografts.

Tumor-induced osteomalacia: clinical and basic studies

A patient with classic clinical and biochemical features of tumor-induced osteomalacia (hypophosphatemia, phosphaturia, and undetectable serum concentrations of 1,25-dihydroxyvitamin D [1,25(OH)2D]) was studied before and after resection of a benign extraskeletal chondroma from the plantar surface of the foot. Presurgical laboratory evaluation was notable for normal serum concentrations of calcium, intact parathyroid hormone (PTH), parathyroid hormone-related protein (PTHrP), and osteocalcin, increased serum alkaline phosphate activity, and frankly elevated urinary cyclic adenosine monophosphate (cAMP) and pyridinium cross-link excretion. Quantitative histomorphometry showed severe osteomalacia and deep erosions of the cancellous surface by active osteoclasts. After resection, serum 1,25(OH)2D normalized within 24 h, while renal tubular phosphorus reabsorption and serum phosphorus did not normalized until days 2 and 3, respectively; serum Ca declined slightly, and serum intact PTH, osteocalcin, and urinary pyridinium cross-link excretion increased dramatically. Urinary cAMP excretion declined immediately after resection and then began to increase concomitant with the increase in serum intact PTH. A second bone biopsy taken 3 months after resection demonstrated complete resolution of the osteomalacia, increased mineral apposition rate (1.09 mu/day), resorption surface (9.2%), mineralizing surface (71%), and bone formation rate (0.83 mm3/mm2/day), and marked decrease in cancellous bone volume (13.1%) and trabecular connectivity compared with first biopsy. Tumor extracts did not affect phosphate transport in renal epithelial cell lines or 1 alpha-hydroxylase activity in a myelomonocytic cell line. The patient's course suggests that the normal 1,25(OH)2D and phosphorus metabolism is due to a tumor product that may be acting via stimulation of adenylate activity. Increased bone resorption prior to surgical resection suggests that the tumor may also produce an osteoclast activator. The rise in resorption surface and pyridinium cross-link excretion, increase in serum osteocalcin and bone mineralization, normalization of osteoid width, and fall in cancellous bone volume after resection are consistent with healing of osteomalacia by rapid remodeling.

Reflex sympathetic dystrophy: the clinician's perspective

Theories on the etiology of reflex sympathetic dystrophy (RSD) are reviewed and presented in three categories: peripheral, spinal, and supraspinal. The peripheral pathophysiology involves a prolonged inflammatory, response to injury due to the axon reflex with release of vasoactive neuropeptides and sensitized nociceptors. The spinal component of RSD genesis involves nociceptive spinal cord neurons with lowered thresholds due to chronic pain input. These sensitized spinal neurons respond in turn by signaling pain reflexes through the sympathetic system. A physical-emotional diathesis may predispose individuals to respond to stress through autonomic arousal. Autonomic arousal, coupled with injury, signals the supraspinal influence on this syndrome. Since the puzzle of RSD remains to be solved, measurement and treatment strategies are suggested to provide intervention at each level. Measurement techniques should include a battery of static tests and stress tests. Static tests are used to quantify a physiological parameter at one point in time. Stress tests access physiological response to various neuro-vaso-motor challenges. A "hands off" treatment regime is presented that includes pain control, methods to reset sensory thresholds, vasomotor challenges, and an active motion program.