Plasticity of vagal afferents at the site of an incision in the wall of the stomach

Our objectives were to determine whether the vagal afferent innervation of the stomach reorganizes after surgery and to observe how different wound closure techniques might influence such a process. The smooth muscle wall of the stomach served as a model because it is densely innervated by vagal axons and is frequently compromised by gastric surgery. Male Sprague-Dawley rats were assigned to one of six groups: three groups served as controls in which the stomach was exposed surgically and a) subjected to no further manipulation, b) traumatized with suture needle punctures of the muscle wall, or c) insulted by the placement of knotted suture thread in the stomach muscle; three surgical groups received a 1.0 cm incision through the ventral muscle wall of the stomach that was closed using either a) absorbable sutures, b) fibrin glue, or c) n-butyl cyanoacrylate. Rats were killed 4 to 7 months post-surgery. Prior to euthanasia, Micro-Ruby was injected into the left nodose ganglion of each rat to label vagal afferent axons and terminals. Twelve days post-injection, the stomachs were processed for microscopy. All groups recovered quickly from surgery, without differences in body weight. The presence of suture material in the muscle wall of the stomach was sufficient to produce reorganization of nearby vagal afferents. In addition, we observed that an incision of the smooth muscle wall of the stomach and the associated damage to vagal afferents provoked reorganization and regeneration of vagal afferents. Vagal remodeling at the incision was characteristic of axonal patterns found in neuromas (unlike the organized regeneration and differentiation that can occur after axotomy central to the target organ). Vagal afferent terminals located at the site of the incision were free nerve endings and growth cone profiles, and not the characteristically complex end organs normally found in the smooth muscle. Finally, the pattern of vagal plasticity was influenced by the wound closure technique used. Overall, the remodeling of afferents was aberrant in nature, and such neural pathology could contribute to the neuropathic symptoms and hyperalgesias associated with gastrointestinal trauma and bariatric surgery.     

Possible sources of neuroprotection following subretinal silicon chip implantation in RCS rats

Current retinal prosthetics are designed to stimulate existing neural circuits in diseased retinas to create a visual signal. However, implantation of retinal prosthetics may create a neurotrophic environment that also leads to improvements in visual function. Possible sources of increased neuroprotective effects on the retina may arise from electrical activity generated by the prosthetic, mechanical injury due to surgical implantation, and/or presence of a chronic foreign body. This study evaluates these three neuroprotective sources by implanting Royal College of Surgeons (RCS) rats, a model of retinitis pigmentosa, with a subretinal implant at an early stage of photoreceptor degeneration. Treatment groups included rats implanted with active and inactive devices, as well as sham-operated. These groups were compared to unoperated controls. Evaluation of retinal function throughout an 18 week post-implantation period demonstrated transient functional improvements in eyes implanted with an inactive device at 6, 12 and 14 weeks post-implantation. However, the number of photoreceptors located directly over or around the implant or sham incision was significantly increased in eyes implanted with an active or inactive device or sham-operated. These results indicate that in the RCS rat localized neuroprotection of photoreceptors from mechanical injury or a chronic foreign body may provide similar results to subretinal electrical stimulation at the current output evaluated here.     

Mass of the postsynaptic density and enumeration of three key molecules

The total molecular mass of individual postsynaptic densities (PSDs) isolated from rat forebrain was measured by scanning transmission EM. PSDs had a mean diameter of 360 nm and molecular mass of 1.10 +/- 0.36 GDa. Because the mass represents the sum of the molecular masses of all of the molecules comprising a PSD, it becomes possible to derive the number of copies of each protein, once its relative mass contribution is known. Mass contributions of PSD-95, synapse-associated protein (SAP)97, and alpha-Ca2+/calmodulin-dependent protein kinase II (CaMKII) were determined by quantitative gel electrophoresis of PSD fractions. The number of PSD-95 molecules per average PSD, contributing 2.3% of the mass of the PSD, was calculated to be 300, whereas the number of SAP97 molecules, contributing 0.9% of the mass of the PSD, was 90. The alpha-CaMKII holoenzymes, which contribute 6% of the mass when brains are homogenized within 2 min of interrupting blood flow, have 80 holoenzymes associated with a typical PSD. When blood flow is interrupted 15 min before homogenization, the average mass of PSDs increases by approximately 40%. The additional alpha-CaMKII associated with PSDs accounts for up to 20% of this mass increase, representing the addition of 100-200 alpha-CaMKII holoenzymes.     

Combined acute traumatic aortic injury and left main bronchus transection in a 5-year-old child

Blunt traumatic aortic and tracheobronchial injuries are extremely rare in children. We report a case of a 5 year old male who suffered both of these rare injuries (traumatic aortic rupture and left mainstem bronchus transaction). To our knowledge this combination of injuries has not been previously described in a child. CT with multiplanar images was critical for the detection of both injuries.     

Obstetric complications and transition to psychosis in an "ultra" high risk sample

OBJECTIVE: An association between birth and pregnancy complications and the later development of schizophrenia has been described for decades and obstetric complications (OCs) have been proposed as a vulnerability marker for psychosis in line with the neurodevelopmental hypothesis of psychotic disorders. Previous studies of OCs have focused on established schizophrenia. In this study, the association between OCs and the development of psychotic disorder was studied in a group of 74 young people identified as being at very high risk for the first onset of psychosis. METHOD: The "ultra" high risk (UHR) cohort was identified by the presence of subthreshold psychotic symptoms, or a combination of first-degree relative with a psychotic disorder and recent functional decline. Thirty-eight per cent of the cohort developed an acute psychotic episode over the 12-month period after recruitment. As a component of a larger research study, the level of OCs experienced by the UHR cohort was assessed at intake. RESULTS: Obstetric complications were not associated with the later development of psychosis in the UHR group included in this study. CONCLUSIONS: This study does not support a role for OCs as a risk factor for the later development of psychosis; however, we cannot conclude that they should be completely ignored as a candidate risk factor for onset of psychosis. A number of weaknesses of the study suggest that it may be premature to dismiss OCs as a risk factor for the development of psychosis and further research is urged in this area.     

A retrospective follow-up study of body dysmorphic disorder

BACKGROUND: Although research on body dysmorphic disorder (BDD) is increasing, no follow-up studies of this disorder's course of illness have been published. METHODS: The status of 95 outpatients with BDD treated in a clinical practice was assessed by chart review. Standard scales were used to rate subjects at baseline and the most recent clinic visit (mean duration of follow-up, 1.7 +/- 1.1; range, 0.5-6.4 years). Ratings were also done at 6-month intervals over the first 4 years of follow-up. RESULTS: Allowing for censoring, life table analysis estimated that the proportion of subjects who achieved full remission from BDD at the 6-month and/or 12-month assessment was 24.7%; the proportion who attained partial or full remission at 6 months and/or 12 months was 57.8%. After 4 years of follow-up, 58.2% had experienced full remission, and 83.8% had experienced partial or full remission, at one or more 6-month assessment points. Of those subjects who attained partial or full remission at one or more assessment points, 28.6% subsequently relapsed. Between baseline and the most recent assessment, BDD severity and functioning significantly improved: at the most recent assessment, 16.7% of subjects were in full remission, 37.8% were in partial remission, and 45.6% met full criteria for BDD. Greater severity of BDD symptoms and the presence of major depression or social phobia at baseline were associated with more severe BDD symptoms at study end point. All subjects received at least one medication trial, and 34.3% received some type of therapy during the follow-up period. CONCLUSIONS: A majority of treated patients with BDD improved, although improvement was usually partial. Prospective longitudinal studies are needed to further elucidate the course of BDD.     

The association between life events, social support, and antibody status following thymus-dependent and thymus-independent vaccinations in healthy young adults

This study determined whether stressful life events and social support were related to antibody status following both thymus-dependent and thymus-independent vaccinations. Life events in the previous year and customary social support were measured in 57 healthy students at baseline. Antibody status was also assessed at baseline and at five weeks and five months following vaccination with the trivalent influenza vaccine and the meningococcal A+C polysaccharide vaccine. Taking into account baseline antibody titre, high life events scores prior to vaccination were associated with lower responses to the B/Shangdong influenza strain at both five weeks and five months and meningococcal C at five weeks. Life event scores were not associated with response to the other two influenza viral strains nor response to meningococcal A. Those with high social support scores had stronger 5-week and 5-month antibody responses to the A/Panama influenza strain, but not to any of the other strains. These associations could not be accounted for by demographic or health behaviour factors, and also emerged from analyses comparing those who exhibited a fourfold increase in antibody titre from baseline with those who did not. Life events and social support were related to antibody status following influenza vaccination in distinctive ways that may be partly determined by vaccine novelty and prior naturalistic exposure. Life events also predicted poor antibody response to meningococcal C polysaccharide vaccination after previous meningococcal C conjugate vaccination. Neither psychosocial factor was associated with response to primary meningococcal A polysaccharide vaccination.