Outcome of kidney transplantation from elderly donors after cardiac death

BACKGROUND

The rate of renal transplantation is limited by the number of donor organs available. A valuable source of organs is currently supplied by donation after cardiac death (DCD). At the Richard Bright Renal Unit, we have expanded our criteria for DCD, increasing the upper age limit for donation from 65 to 70.

METHOD

We performed a retrospective analysis of all DCD recipients between 2003 and 2009. We compared outcomes for patients age<60 versus >60 as measured by delayed graft function and estimated glomerular filtration rate (eGFR) and incidence of graft failure.

RESULTS

One hundred thirty-six DCD transplantations took place. Our early data showed excellent results for non-heart-beating donation. Over the last 7 years, the average age of DCD donors has increased from 43 in 2003 to 50 in 2009. The increase in age has been correlated with a decrease in average recipient eGFR from 59 in 2003 to 32 in 2009. Recipients of kidneys from older DCD donors (>60) have significantly lower eGFRs at 1 month and 1 year compared to kidneys from donors aged <60. The incidence of delayed graft function in recipients of kidneys from donors aged>60 was 71% compared to 40% for <60 age group. Despite this, we have not found any evidence of higher graft failure rates in the recipients of grafts from the >60 donor age group.

CONCLUSIONS

Expanding the age limits of our DCD donor program has led to an increased average donor age, reduced average eGFR, and increased delayed graft function. There is no evidence of reduced graft survival.

Fentanyl self-administration in juvenile rats that were tolerant and dependent to fentanyl as infants

Human neonates and infants can become tolerant and dependent during continuous fentanyl or morphine administration. The long-term consequences in these individuals as juveniles and adults are unknown. This study compared fentanyl self-administration behavior in juvenile rats that were opioid naive or were exposed chronically to fentanyl as infants. Postnatal day 14 infant rats remained naive or were implanted with saline- or fentanyl-filled Alzet minipumps. After 72 h, fentanyl's antinociceptive potency was 3.0-fold lower in the fentanyl-infused rats. Naloxone precipitated withdrawal occurred only in the fentanyl-infused animals. Other similarly treated infant rats were allowed to mature into P42 juvenile rats before enrolling them in an oral fentanyl self-administration study. Rats from each group consumed significantly more fentanyl than quinine. However, those rats, tolerant and dependent to fentanyl as infants, did not self-administer more fentanyl than their opiate-naive littermates. The issue of whether fentanyl was consumed for its reinforcing properties was demonstrated when noncontingent administration of opiate antagonists significantly reduced fentanyl intake in another group of juvenile rats. These data indicate that fentanyl is consumed for its reinforcing properties, but that infant fentanyl tolerance and dependence did not predispose them to self-administer more fentanyl than opiate-naive animals.

Comparing astrocytic cell lines that are inhibitory or permissive for axon growth: the major axon-inhibitory proteoglycan is NG2

Astrocytes, oligodendrocytes, and oligodendrocyte/type 2 astrocyte progenitors (O2A cells) can all produce molecules that inhibit axon regeneration. We have shown previously that inhibition of axon growth by astrocytes involves proteoglycans. To identify inhibitory mechanisms, we created astrocyte cell lines that are permissive or nonpermissive and showed that nonpermissive cells produce inhibitory chondroitin sulfate proteoglycans (CS-PGs). We have now tested these cell lines for the production and inhibitory function of known large CS-PGs. The most inhibitory line, Neu7, produces three CS-PGs in much greater amounts than the other cell lines: NG2, versican, and the CS-56 antigen. The contribution of NG2 to inhibition by the cells was tested using a function-blocking antibody. This allowed increased growth of dorsal root ganglion (DRG) axons over Neu7 cells and matrix and greatly increased the proportion of cortical axons able to cross from permissive A7 cells onto inhibitory Neu7 cells; CS-56 antibody had a similar effect. Inhibitory fractions of conditioned medium contained NG2 coupled to CS glycosaminoglycan chains, whereas noninhibitory fractions contained NG2 without CS chains. Enzyme preparations that facilitated axon growth in Neu7 cultures were shown to either degrade the NG2 core protein or remove CS chains. Versican is present as patches on Neu7 monolayers, but DRG axons do not avoid these patches. Therefore, NG2 appears to be the major axon-inhibitory factor made by Neu7 astrocytes. In the CNS, NG2 is expressed by O2A cells, which react rapidly after injury to produce a dense NG2-rich network, and by some reactive astrocytes. Our results suggest that NG2 may be a major obstacle to axon regeneration.

Long-term alterations in opiate antinociception resulting from infant fentanyl tolerance and dependence

Postnatal day-14 (P14) infant rats remained naive or were implanted with osmotic minipumps infusing saline or fentanyl (50 microg kg(-1) h(-1)). Fentanyl was administered 72 h later for measurement of antinociception in the tail-flick test. The potency of fentanyl was 3.0-fold lower in fentanyl-infused compared to saline-infused P17 rats. Fentanyl-infused P17 rats injected with naloxone underwent withdrawal characterized by increases in spontaneous activity, wall climbing, diarrhea, abdominal stretching, forepaw treading/tremors, wet-dog shakes, jumping, ptosis, rhinorrhea and hypothermia. Other naive, saline-infused and fentanyl-infused P17 rats not challenged with fentanyl or naloxone were housed until maturing into P42 juveniles. Fentanyl's potency was equal among each treatment group. However, morphine's potency was reduced in juveniles tolerant to fentanyl as infants. Morphine was also less potent in P90 adults tolerant to fentanyl as infants. Thus, chronic opiate exposure during infancy may affect the developing central nervous system, and desensitize animals and humans to opiate analgesia throughout life.

Prevalence of premilitary adult sexual victimization and aggression in a Navy recruit sample

U.S. Navy recruits (n = 3,776) were surveyed for premilitary histories of adult sexual assault. They completed a survey designed to estimate rates for experiences as victims (women) and perpetrators (men) of attempted and completed rape since the age of 14. The results show that 45.5% of the women reported being the victim of attempted (9.4%) or completed rape (36.1%) before entering the Navy. Male recruits' self-reports indicated that 14.8% admitted perpetrating attempted (3.5%) or completed rape (11.3%) before entering the Navy. A high percentage of recruits in this study reported histories of sexual assault. Female victims of sexual assault are at high risk of incurring somatic and/or psychological problems that require treatment by health care professionals. Male perpetrators of sexual assault are at high risk of repeating their behavior. The results of this study suggest that it may be cost-effective to develop treatment education, and prevention programs for military recruits.

Ontogeny of mu opioid agonist anti-nociception in postnatal rats

Mu opiate agonists morphine, fentanyl and meperidine are administered short-term to pediatric patients, from the neonatal period through adolescence. However, there has been no assessment of the effect of age on the analgesic efficacy or the concentration-response relationship for these opioids in human pediatric patients. Few studies in animals have correlated opioid anti-nociception and tissue levels of these opioids commonly administered to pediatric patients. The present study was conducted to examined the role of age on opioid anti-nociceptive potency and efficacy and brain and plasma opioid levels to provide predictive information on the effect of opioids in developing humans. Administration of trace amounts of tritiated drug with anti-nociceptive doses of unlabeled drug was used for the assessment of anti-nociception in the tail-flick test and for the measurement of brain and plasma drug equivalent levels in postnatal rats (PND 3-21). Morphine and fentanyl were completely efficacious in all postnatal ages examined, although age-related differences in drug potency, as well as, differences in brain and plasma levels were observed. There was a good correlation between morphine (r = 0.96) and fentanyl (r = 0.89) ED(50) values and their respective brain and plasma EC(50) equivalent levels. Meperidine had limited efficacy in young rats (PND 3-9) but was completely efficacious in older rats (PND 14-17). However, PND 21 rats experienced tonic-clonic seizures which limited its efficacy to 70% anti-nociception. Our data suggest that pharmacokinetics, the development of the blood-brain barrier and ontogeny of opioid receptor function may play important roles in the sensitivity of postnatal rats to mu receptor agonists.

Characterization of neonatal rat morphine tolerance and dependence

The administration of morphine and fentanyl by continuous intravenous infusion has been shown to produce analgesic tolerance and physical dependence in human neonates. In animals, daily repeated morphine bolus injections is a common method of inducing neonatal rat tolerance and dependence. Yet this method differs from the intravenous route reported to affect human neonates. Alzet osmotic minipumps were implanted in postnatal day 14 rats to provide a continuous morphine infusion more closely mimicking the clinical picture. Rats remained naive or were infused with saline or morphine (0.7 mg/kg/h) for 72 h. Morphine's antinociceptive potency was similar between naive and saline-infused animals, while morphine-infused animals were tolerant. Gender did not contribute to the degree of tolerance observed. Naloxone precipitated withdrawal in the morphine pump-implanted rats was similar to that reported by others. Thus, minipumps provide a useful model for assessing the tolerance and dependence liability of different opioids.

Characterization of neonatal rat fentanyl tolerance and dependence

Fentanyl and morphine are administered to human neonates and infants to provide analgesia and sedation during painful and stressful procedures. These opioids have often been shown to produce tolerance and dependence during continuous intravenous infusion. In neonatal animals, morphine produces tolerance and dependence, yet little is known about fentanyl. This report describes the first model for studying opioid tolerance and dependence in neonatal animals with use of osmotic minipumps. Postnatal day 6 rat pups were anesthetized and then remained naive or were surgically implanted subcutaneously with Alzet osmotic minipumps containing either saline or fentanyl (100 microg/kg/hr). Tolerance and dependence were assessed 72 hr after implantation. The ED50 values for fentanyl antinociception in the tail-flick test were not different between naive and saline pump-implanted animals. However, the fentanyl pump-implanted animals were tolerant to fentanyl. The tolerance observed was not the result of gender, developmental changes, fentanyl distribution or changes in fentanyl metabolism. These results indicate that continuous administration of fentanyl via osmotic minipump can render normal neonatal rats tolerant and physically dependent on fentanyl in 72 hr. Withdrawal precipitated by naloxone (5 mg/kg s.c.) in the fentanyl pump-implanted animals was characterized by increased spontaneous activity, micturition/defecation, wall climbing, abdominal stretching, tremors, scream on touch and spontaneous vocalization. This new model may provide a tool for studying the long-term consequences of neonatal opioid exposure in juvenile and adult animals.

Workplace literacy education: writing skills

Remedial programs must be flexible and planned to meet the needs of the participants. Using both work and creative writing exercises provides a balance and relieves boredom. Educators need to be alert to the varying education and skill level of employees. For example, many management development program planners assume a certain level of literacy and English fluency among the managerial group. As a result, some supervisors may avoid programs or not learn the material because of difficulty in comprehending the material. The basic thread of our program was the integration of humor and content. Few classes ended without laughter. This laughter was not at the expense of an individual's self-esteem. We laughed at humorous examples of unclear writing and mistakes unintentionally made by the instructors. We laughed at some of their own humorous writing. One of the participants wrote a particularly amusing and entertaining story of a disastrous camping trip. Other times members delighted in catching mistakes in hospital communications. It was obvious that they were reading with more alertness. An unexpected result of the program was the increased rapport between the involved supervisors, their managers, our department, and our local community resources. The program opened channels that have led to an on-site GED program and closer ties with the county literacy efforts. Managers in plant services have increased their involvement and support for employees seeking to improve their education. The TMC educational reimbursement system has been made more available for all.