Temporal segmentation of response speed in depression: neuro-electrophysiological approaches

1. Depressive psychomotor retardation, as observed by delayed reaction times (RT), may be related to a slowing in information processing speed. 2. Two separate studies compared indices of information processing speed in depressed patients and non-clinical controls by segmenting behavioral RT with brain event-related potentials (ERPs) and electromyographic (EMG) responses. 3. In Study I, slower behavioral RTs in depression were concomitant with slower central processing times (CPT) but not motor execution times (MET). 4. In Study II, P165, a putative early cognitive ERP related to 'stimulus evaluation time', was found to be slower but within normal range in depressed patients.     

REPAIR AND RECOVERY FOLLOWING SPINAL CORD INJURY IN A NEONATAL MARSUPIAL (MONODELPHIS DOMESTICA)

1. Repair and recovery following spinal cord injury (complete spinal cord crush) has been studied in vitro in neonatal opossum (Monodelphis domestica), fetal rat and in vivo in neonatal opossum. 2. Crush injury of the cultured spinal cord of isolated entire central nervous system (CNS) of neonatal opossum (P4–10) or fetal rats (E15–E16) was followed by profuse growth of fibres and recovery of conduction of impulses through the crush. Previous studies of injured immature mammalian spinal cord have described fibre growth occurring only around the lesion, unless implanted with fetal CNS. 3. The period during which successful growth occurred in response to a crush is developmentally regulated. No such growth was obtained after P12 in spinal cords crushed in vitro at the level of C7–8. 4. In vivo, in the neonatal (P4–8) marsupial opossum, growth of fibres through, and restoration of, impulse conduction across the crush was apparent 1–2 weeks after injury. With longer periods of time after crushing a considerable degree of normal locomotor function developed. 5. By the time the operated animals reached adulthood, the morphological structure of the spinal cord, both in the region of the crush and on either side of the site of the lesion, appeared grossly normal. 6. The results are discussed in relation to the eventual longterm possibility of devising effective treatments for patients with spinal cord injuries.     

CORTICAL SLOW POTENTIAL CHANGES IN MAN RELATED TO INTERSTIMULUS INTERVAL AND TO PRE TRIAL PREDICTION OF INTERSTIMULUS INTERVAL

Two experiments were performed to explore further the relationship between the cortical slow potential change known as the “contingent negative variation” (CNV) and the concept of “expectancy.” In Experiment I, 24 male Ss were presented click pairs, with inter-click intervals of 800, 1600 and 4800 msec (2 blocks of 10 trials each, counterbalanced between Ss for order), and instructed to press a key after the second click. Interval by order by trials analysis of variance showed interval to be the only significant factor: CNVs were lower and RTs longer as interval increased. In Experiment II, 8 female Ss given 60 pairs of clicks, 30 each with separations of 1200 and 2400 msec, were instructed to respond as in Experiment I, and were asked to make a pretrial prediction of the interval they would next receive. Analysis of variance of RTs showed that Ss responded slower when the interval was other than that predicted. Prediction by reception by subjects analysis of variance of CNV amplitude at the 1200 msec point gave a significant F only for prediction, mean amplitude for short being higher than for long. A similar design applied to CNV amplitudes at both the 1200 and 2400 msec points when Ss received the long interval yielded a significant measurement point by interval predicted interaction; at the 1200 msec point, short predictions were followed by higher CNVs than were long predictions; at 2400 msec, the opposite was found. These data combine with those already in the literature to indicate that the relationship between “expectancy” and the CNV is far from simple, and that cognitive and motivational factors play a significant role in determining CNV amplitude.     

Impact of an organ donor and tissue donor advocacy program on community hospitals

A crucial shortage of organ donors exists in the United States. The majority of donor referrals come from large (greater than 500) beds) hospitals and trauma centers. To determine whether a significant number of donors who are not being recognized or referred also existed in medium-sized (300 beds) community hospitals, a Donor Advocacy Program was instituted at Francis Scott Key Medical Center in May 1987. This team developed policies and procedures to identify potential donors and conducted educational programs for physicians and nurses. A designated "Donor Advocate" made daily rounds on the inpatient units to maintain donor awareness and facilitate potential donations. After the first year, the program was evaluated. In comparison to the average of the previous three years, donor referrals increased by approximately 400 per cent and tissue donations increased over 500 per cent. Four organs were retrieved from two donors. It is concluded that an increase in referrals and tissue donations can be achieved at community hospitals through a structured donor awareness program. Recommendations are made to further examine the age group most often eligible for organ and tissue donations in community hospitals and target educational efforts accordingly. Commitment of hospital administration is vital to a positive outcome in such a program.     

Upregulation of alpha-synuclein in neurons and glia in inflammatory demyelinating disease

A growing body of evidence suggests that axonal loss and neurodegeneration are responsible for the permanent neurological deficit that typically develops in the course of MS. To investigate the neurodegenerative component of MS pathogenesis, we examined the expression of alpha-synuclein, a protein whose accumulation is common to many neurodegenerative disorders, under conditions of immune-mediated inflammatory demyelination. alpha-Synuclein expression was examined in the spinal cord of myelin oligodendrocyte glycoprotein (MOG)-induced experimental autoimmune encephalomyelitis (EAE) in rats using immunofluorescence and in situ hybridization and in postmortem tissues from cases of secondary progressive MS using immunohistochemistry. alpha-Synuclein upregulation was detected in neurons and glia in and close by lesions and in normal appearing spinal cord EAE tissue at the protein and mRNA levels. alpha-Synuclein positive neurons and glia appeared early, and their number was maximal during EAE exacerbations, but some expression was maintained throughout the course of EAE. In addition, increased alpha-synuclein expression was detected in neurons and glia in and close to MS lesions. Although the increased expression of alpha-synuclein was detected as a granular cytoplasmic labeling rather than inclusion bodies, this result does suggest that neuronal cell death in immune-mediated demyelinating disease may share some common features with other neurodegenerative conditions.     

Bax deficiency rescues resection-induced enterocyte apoptosis in mice with perturbed EGF receptor function

BACKGROUND: Adaptation after massive smallbowel resection (SBR) is associated with increased cell turnover, increased rates of enterocyte proliferation, and apoptosis. Epidermal growth factor receptor (EGFR) inhibition attenuates adaptation and increases apoptosis. Intestinal levels of bax appear to correlate with EGFR signaling. This study tested the hypothesis that bax is required for the exaggerated postresection apoptosis induced by perturbed EGFR signaling. METHODS: Waved-2 mice with impaired EGFR signaling were crossbred with bax-null mice. Offspring were subjected to either 50% proximal SBR or sham operation (bowel transection and reanastomosis). After 7 days, parameters of adaptation (villus height, wet weight), proliferation (% Ki-67 immunostaining of crypt cells), and apoptosis (# apoptotic bodies per crypt) were recorded in the remnant ileum. RESULTS: Enterocyte apoptosis was increased in waved-2 mice and prevented in bax-null mice after SBR. The accelerated apoptosis in the waved-2 mice was rescued in the context of deficient bax expression. Other parameters of adaptation were restored in the bax-null/waved-2 mice. CONCLUSION: Bax is required for the induction of postresection enterocyte apoptosis. Defective EGFR signaling augments resection-induced enterocyte apoptosis via a mechanism that also requires bax expression. These data implicate a link between EGFR signaling and bax in the genesis of postresection apoptosis and adaptation.     

Interval appendectomy after perforated appendicitis: what are the operative risks and luminal patency rates?

BackgroundThe need for interval appendectomy after nonoperative management of a perforated appendicitis is being questioned owing to recent studies that estimated recurrence rates as low as 5% because of obliteration of the appendiceal lumen. We review our experience with interval appendectomy in this subset of patients to determine the postoperative outcomes and luminal patency rates.MethodsA retrospective review was conducted of all children treated nonoperatively for a perforated appendicitis followed by elective interval appendectomy during the past 10 years. The data collected included initial hospitalization, convalescence period, perioperative course, and luminal patency rates.ResultsA total of 128 patients were identified, of whom 55% were male. Their mean ± SD age was 9.1 ± 4.2 years. The mean interval from the initial presentation to appendectomy was 65.9 ± 20.3 d. All but 2 of the patients underwent laparoscopic appendectomy with 3 conversions to open surgery. The mean operative time was 43.6 ± 19.2 min. The complication rate was 9%, including 1 postoperative abscess, 1 reoperation for bleeding, and 1 readmission for Clostridium difficile infection. Six patients had a superficial wound infection, and 2 patients underwent outpatient procedures for suture granuloma. No risk factors for complications were identified. Of the specimens, 16% had obliterated lumens.ConclusionsMajor postoperative morbidity for interval appendectomy after a perforated appendicitis is low and should not be a deterrent in offering interval appendectomy to this subset of patients.