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Background: Medical decision-making capacity is impaired in Alzheimer’s disease and mild cognitive impairment. Medical decision-making capacity depends on many different cognitive functions and varies due to situation and cognitive, social, and emotional status of the patient. Our aim was to analyze dementia patients’ capacity to estimate risks and benefits in different clinical trials and determine how cognitive decline affects their attitude toward possible participation and proxy consent. Methods: Groups: Alzheimer’s disease (n = 20), mild cognitive impairment (n = 21) and healthy controls (n = 33). Two hypothetical clinical trials, a standardized interview and three visual analogue scales were used to investigate decisions, estimations, reasoning, and attitudes. Results: A general positive attitude toward participation in clinical trials was shown among all groups. Both patients and controls motivated possible participation as “own-benefit” in the low-risk trial and to “help-others” in the high-risk trial. Individuals who accepted to participate in the high-risk trial scored lower in medical decision-making capacity in comparison to participants who would not have participated (p < .01). Patients in the Alzheimer’s disease but not mild cognitive impairment and healthy control groups underestimated risks and overestimated benefits in the high-risk/low-benefit trial (p < .05). A family member was most frequently chosen as possible proxy (91%). Conclusions: Medical decisions and research consent should be interpreted with caution in patients who are already in early stages of dementia, as the patients’ acceptance to participate in high-risk trials may be due an insufficient decisional capacity and risk analysis, accelerated by a general desire to make good to society. We emphasize the use of a standardized tool to evaluate medical decisional capacity in clinical research.

Amniotic fluid (AF) surrounds the growing fetus, and cells derived from AF are commonly used for diagnosis of genetic diseases. Intra-amniotic infections are strongly linked to preterm birth, which is the leading cause of perinatal mortality worldwide. Surprisingly little is known, however, about mature hematopoietic cells in AF, which could potentially be involved in immune responses during pregnancy. In this study, we show that the dominating population of viable CD45+ cells in AF is represented by a subset of fetal CD103+ group 3 innate lymphoid cells (ILCs) producing high levels of IL-17 and TNF. Fetal CD103+ ILC3s could also be detected at high frequency in second-trimester mucosal tissues (e.g., the intestine and lung). Taken together, our data indicate that CD103+ ILC3s accumulate with gestation in the fetal intestine and subsequently egress to the AF. The dominance of ILC3s producing IL-17 and TNF in AF suggests that they could be involved in controlling intra-amniotic infections and inflammation and as such could be important players in regulating subsequent premature birth.

Udgivelsesdato: 2002-Jan, Here we present evidence for spontaneous and long-lasting regeneration of CNS axons after spinal cord lesions in adult rats. The length of 200 kD neurofilament (NF)-immunolabeled axons was estimated after photochemically induced ischemic spinal cord lesions using a stereological tool. The total length of all NF-immunolabeled axons within the lesion cavities was increased 6- to 10-fold at 5, 10, and 15 wk post-lesion compared with 1 wk post-surgery. In ultrastructural studies we found the putatively regenerating axons within the lesion to be associated either with oligodendrocytes or Schwann cells, while other fibers were unmyelinated. Immunohistochemistry demonstrated that some of the regenerated fibers were tyrosine hydroxylase- or serotonin-immunoreactive, indicating a central origin. These findings suggest that there is a considerable amount of spontaneous regeneration after spinal cord lesions in rodents and that the fibers remain several months after injury. The findings of tyrosine hydroxylase- and serotonin-immunoreactivity in the axons suggest that descending central fibers contribute to this endogenous repair of ischemic spinal cord injury.

We have characterized the evolving morphological changes in the adult rat spinal cord following photochemically induced spinal cord ischemia. In cresyl violet-stained sections, disintegration of the tissue at the epicenter was evident at 6 h. This was preceded at 1 h post ischemia by an albumin immunoreactivity. The albumin immunoreactivity was increased at 6 and even more so at 24 h post ischemia. At 72 h post ischemia the albumin immunoreactivity was decreased. The size of the lesion was established by 3 days after the onset of ischemia. During the 1st week post ischemia, neurofilament (NF) immunohistochemistry showed swollen axons adjacent to the injured tissue. From 2 weeks post ischemia an increasing number of regrowing NF-immunoreactive axons could be seen in the center of the necrotic cavity. At 3 weeks after ischemia, a developing gliosis was observed around and rostral to the lesion cavity, as evidenced by increased glial fibrillary acidic protein (GFAP) immunoreactivity. The gliosis became more pronounced until 6 weeks post ischemia, at which time enlarged GFAP-immunoreactive cells could be seen in the remaining viable tissue bordering the necrotic areas. In this study we show that several traits in the development of a spinal cord lesion after photochemically induced ischemia are similar to those described previously after traumatic spinal cord lesions.

Rats subjected to experimental spinal cord compression of different degrees induced by aneurysm clips were neurologically tested 3 and 5 weeks postinjury. The development of spinal cord tissue destruction over time was similar to what has been described for other experimental spinal cord injuries with characteristics such as early edema, axonal swelling, and later necrosis. Three weeks after injury a reactive gliosis was found at the injury epicenter and regenerating axons could be identified in the otherwise necrotic cavity. The extent of degeneration was highly correlated with the closing force of the aneurysm clip. The results of a number of neurological tests were correlated to the degree of clip-induced compression, to lesion volume, and to the remaining area of white matter at the epicenter. The neurological tests with the highest correlation to morphological descriptors were beam walk (r(s) = 0.89-0.95) and motor performance score (r(s) = 0.88-0.92). We conclude that the motor performance score, previously validated for photochemically induced ischemic spinal cord injuries, is equally suitable for clip compression injuries as a fast and reliable neurological test paradigm.

We have investigated the effect of memantine, a clinically used NMDA receptor antagonist, in two experimental animals models of spinal cord injury. The lesions were laser-induced photothrombosis to induce focal spinal cord ischemia and clip compression to mimic traumatic spinal cord injury. Pre- or posttreatment of rats with a dose of memantine (20 mg/kg ip) previously shown to be neuroprotective in cerebral ischemia, failed to affect both the neurological and morphological outcome of ischemic spinal cord injury. Likewise, memantine had no effects on neurological and morphological outcome after experimental traumatic injury. In view of the regional heterogeneity of NMDA receptors, the affinity of memantine for spinal cord NMDA receptors was also determined by studying displacement of [3H] (+)-5-methyl-10,11-dihydro-5-H-dibenzo[a,d]cyclohepten-5-10-imine (MK-801) to rat and human spinal cord homogenates. We found that memantine had an affinity for NMDA receptors in the spinal cord (Ki = 0.58 microM) that was significantly lower compared to that of the cerebral cortex (Ki = 0.23 microM) and that the affinity for NMDA receptors in human spinal cord was even lower. We conclude that in view of available data, memantine should not be chosen for clinical studies on neuroprotection in spinal cord injuries and that the lack of protective effect is most likely due to insufficient affinity of memantine for spinal cord NMDA receptors.

We have used the laser-induced photochemical thrombosis model in adult rats to evaluate the significance of the non-N-methyl-D-aspartate (non-NMDA) subtype of glutamate receptors in situations of focal spinal cord ischemia. The animals were pretreated with the selective non-NMDA antagonist 2,3-dihydroxy-6-nitro-7-sulfamoyl-benzo(f)-quinoxaline (NBQX) or, for comparison, the NMDA antagonist (+)-5-methyl-10,11-dihydro-5H-dibenzo[a,d] cyclohepten-5-10-imine (MK-801). Neurological function was quantified using evaluations of motor score and inclined plane. The MK-801-treated rats had higher motor scores during the 3-week observation period while NBQX-treated rats only performed significantly better at 1 week. Both treatments caused significantly better performance in the inclined plane test. NBQX and MK-801 reduced the volume of necrosis by approximately 47% at 3 weeks postlesion. We conclude that blockade of both NMDA and non-NMDA subtypes of glutamate receptors reduces ischemic necrosis, possibly by preventing excessive stimulation of these receptors by released excitatory amino acids in the lesion area.