Acute plasticity in the human somatosensory cortex following amputation

We studied a patient after amputation of an arm and found that in less than 24 h stimuli applied on the ipsilateral face were referred in a precise, topographically organized, modality-specific manner to distinct points on the phantom. Functional magnetic resonance imaging (fMRI) performed one month later showed that brush-evoked activity in the brain demonstrates objective signal changes which correlate with perceptual changes in the phantom hand. This finding in humans corresponds to the observations of immediate plasticity in cortical pathways described in animals, including primates. The results suggest that reorganization of sensory pathways occurs very soon after amputation in humans, potentially due to the unmasking of ordinarily silent inputs rather than sprouting of new axon terminals.     

Effect of restored and unrestored non-carious cervical lesions on the fracture resistance of previously restored maxillary premolar teeth

OBJECTIVES: The effect of non-carious cervical lesions (NCCL) on tooth fracture resistance has not previously been investigated. The aims of this in vitro study were to examine the fracture resistance of a group of extracted maxillary premolar teeth with mesio-occlusal-distal (MOD) restorations of amalgam, and restored or unrestored simulated NCCL. METHOD: Forty sound maxillary, premolar teeth were divided at random into four groups, each of 10 teeth, which were fixed crown uppermost and long axis vertical in stainless steel moulds. Groups 1,2,3 and 4 were prepared with standardized parallel-sided MOD cavities, then restored with amalgam. Groups 1, 2 and 3 were further prepared with standardized NCCL. The NCCL in Group 1 were restored using a resin-modified polyalkenoate (glass-ionomer) cement, and the NCCL in Group 2 were restored with an adhesive composite resin system. The NCCL in Group 3 were left unrestored. The specimens were loaded compressively at 1 mm min-1 using a universal testing machine. RESULTS: Mean fracture loads (KN) of 1.08, 1.03, 0.98 and 1.14, respectively, were recorded for Groups 1, 2, 3 and 4. Two-way ANOVA and Scheffe's Multiple Range Test showed no statistically significant difference between the groups. CONCLUSIONS: It is concluded that the presence of a standardized NCCL in an extracted maxillary premolar tooth does not reduce the fracture resistance of the tooth when loaded compressively at 1 mm min-1. The restoration of NCCL with the materials tested did not result in an increase in the fracture resistance of the previously restored premolar teeth, when loaded compressively at 1 mm min-1.     

Vascular reaction following intramedullary nailing of the tibia in dogs

We have reinvestigated radioiodinated plasminogen as an agent for localizing preformed thrombi. Canine plasminogen was isolated from fresh plasma by the affinity chromatography technique on a lysine-sepharose 4B column and tagged with I-123 or I-131, at less than one iodine atom per molecule of enzyme, by the conventional ICI method. When injected into dogs more than 2 days after thrombus induction, radioiodinated plasminogen produced thrombus-to-blood activity ratios of 7.8 +/- 2.4. Thrombi as old as 6 days can be visualized in 80% of the cases. Both the weight of the thrombus and the thrombus-to-blood ratio are more variable for 1-day-old thrombi; this may be associated with plasminogen release accompanying thrombus retraction. The results suggest that radioiodinated plasminogen has potential as an imaging agent for pre-existing thrombi.     

The importance of cognitive processing to adjustment in the 1st year following amputation.

Objective: To describe depressive symptoms, posttraumatic stress disorder (PTSD), and posttraumatic growth at 6 and 12 months following amputation and to explore differences by demographic variables and cognitive processing of trauma. Participants: 83 adults with newly acquired limb loss. Setting: Two large metropolitan hospitals. Main Outcome Measures: The Patient Health Questionnaire depression module, PTSD Checklist, and Posttraumatic Growth Inventory. Results: Significant depressive and PTSD symptoms were reported by 15%-25% of participants. Relatively low levels of posttraumatic growth were reported. Negative cognitive processing predicted depressive and PTSD symptoms at 6 months. Positive cognitive processing predicted posttraumatic growth at 12 months. Conclusion: Cognitive processing appears to be integral to positive and negative psychosocial outcomes following amputation and should be targeted by clinical interventions. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Histological presence of viable prostatic glands on routine biopsy following cryosurgical ablation of the prostate

PURPOSE: Cryosurgical ablation of the prostate has recently received much attention as a therapeutic alternative for the treatment of localized prostatic adenocarcinoma. Biopsies after treatment reveal a variety of dysplastic changes as well as unaltered prostatic glandular epithelial elements. Prostate specific antigen (PSA) remains undetectable in the majority of men. However, in some PSA increases without demonstrable local recurrence. MATERIALS AND METHODS: A total of 383 patients underwent 447 procedures between June 1990 and January 1994. Of 358 biopsies performed at our institution, 317 (2,075 cores) were available for review. Each core was examined for unaltered prostatic glandular epithelial elements and then scored for the percentage of epithelial glandular involvement according to a scale of: 0-no, 0.5-less than 10%, 1-10 to 25%, 2-25 to 50%, 3-50 to 75% and 4-76 to 100% unaltered prostatic glandular epithelial elements. RESULTS: Of 317 biopsies 158 (49.8%) contained no unaltered prostatic glandular epithelial elements, while 185 (58.3%) and 206 (65%) had 1 core containing 10% and 10 to 25%, respectively, of such elements. Of 262 cases (82.6%) with a mean of 10% unaltered prostatic glandular epithelial elements per core 22 (8.4%) were positive for residual carcinoma. Among 55 cases with more normal epithelium per core 24 (43.6%) were positive for residual carcinoma. Patients with a positive biopsy had a median PSA of 2.02 ng./ml. (average gland/core score 0.54). Median PSA for men with negative biopsies was 0.2 ng./ml. (gland/core score 0.124). CONCLUSIONS: Cryosurgical ablation of the prostate has the ability to ablate prostatic tissue completely, thus rendering it free of glandular elements as determined by biopsy. Increasing PSA can indicate residual glandular elements. Increases in unaltered prostatic glandular epithelial elements with time are not paralleled by increased rates of local disease recurrence. undetectable serum PSA has a low risk of residual unaltered prostatic glandular epithelial elements and localized carcinoma. Results as measured by unaltered prostatic glandular epithelial elements and PSA improve with the surgical experience.     

Inhibition of ingestive behavior following fourth ventricle bombesin injection in chronic decerebrate rats.

Tested the hypothesis that the effects of 4th ventricle bombesin (BN) injection on feeding require interaction with forebrain neural systems by measuring intraoral sucrose (0.1 M) in tube-fed control and tube-fed supracollicular decerebrate rats after 4th ventricle injections of 1, 5, 10, 20, and 50 ng BN. Fourth ventricle injections of all doses of BN reliably suppressed sucrose intake in both control and chronic decerebrate rats. These results indicate that caudal brain-stem afferent signals produced by 4th ventricle BN injections are integrated by the local neural circuitry of the caudal brain stem, independent of the forebrain systems, to modulate ingestive behavior. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Osteogenic sarcoma of the maxillary alveolus occurring five years following the Chernobyl nuclear accident

A novel member of the opioid receptor family (orphan ORL receptor) was cloned in 1994, followed by the discovery of its endogenous ligand OFQ or nociceptin in 1995. ORL receptor has 50% homology with conventional opioid receptor, and OFQ is structurally homologous with dynorphin A. Whether the two systems are functionally antagonistic or synergistic with each other is a subject of future research.     

Evaluation of the vital reaction in injuries

Demographic, social, and medical analysis of more than 30,000 suicide cases in a large region of Russia (Krasnodar region) over 1969-1994 showed the prevalence of men, subjects aged over 60, divorced and widowed subjects, individuals living alone, subjects without permanent occupation, mental patients, chronic alcoholics, and invalids in this group. The principal factors determining the processes of formation of the totality of suicides have been determined and the most prevalent social and hygienic characteristics of a suicide described. Groups with the highest level of suicides have been identified: narcomaniacs, mental patients, chronic alcoholics, disabled subjects. The authors emphasize not so much the medical, but the social aspect of the problem. They offer the priority research trends and organization measures aimed at investigation of the suicide phenomena and prevention thereof.     

Anatomical regeneration and behavioral recovery following crush injury of the trigeminal root in lamprey

In normal larval lamprey, bilateral application of horseradish peroxidase (HRP) to the dorsal part of the anterior oral hood labeled subpopulations of trigeminal components on both sides of the brain; peripherally projecting motoneurons, medullary dorsal cells (sensory), and spinal dorsal cells (sensory), as well as centrally projecting afferents in the trigeminal descending tracts. Following unilateral crush injury of the right trigeminal root, HRP labeling of sensory and motor trigeminal components on the right side gradually increased with increasing recovery time, between 2 weeks and 12 weeks postcrush (PC). Axons of trigeminal motoneurons appeared to exhibit robust regeneration, whereas restoration of projections in the descending trigeminal tract ipsilateral to the injury was incomplete. Control experiments indicated that motor and sensory axons from the intact side of the oral hood did not sprout across the midline to the denervated side. Several results suggested that regenerated trigeminal sensory fibers made synapses with brain neurons that have direct or indirect inputs to reticulospinal (RS) neurons. Following a unilateral crush injury of the right trigeminal root, escape behavior in response to stimulation of the right side of the oral hood gradually returned to normal. Muscle recordings at various recovery times confirmed that anatomical regeneration of trigeminal sensory axons was functional. In addition, at 8 or 12 weeks PC, brief stimulation of the oral hood ipsilateral or contralateral to the crush injury elicited synaptic responses in RS neurons on either side of the brain, similar to that in normal animals. In the lamprey, compensatory mechanisms probably allow recovery of behavioral function despite incomplete regeneration of trigeminal sensory axons within the central nervous system.     

Restoration of the electrical activity and nervous apparatus following section of the stomach wall in dogs

In dogs, transection of the gastric wall at the level of incisura angularis, followed by end--to--end anastomosis, was made. The electrodes were implanted into the muscle wall of the two stomach segments. Electrical activity of the stomach wall on the 1st postoperative day showed dissociation in the spike activity between the two segments. 10 days later, first signs of sequence in the spike activity of the stomach above and below the anastomosis appeared. Microscopic examination revealed that regenerating nerve fibers formed a bridge over the scar. On the 16th day, groups of spike potentials from the gastric wall above the section propagated also in the stomach region below the anastomosis. Since the 14th day, the microscopic examination revealed newly formed synaptic endings on the ganglionic cells distal to the scar. After the 20th day, all signs of dissociation began to disappear.     

Impaired learning of classically conditioned bradycardia in rats following fourth ventricle administration of D-ala2-methionine-enkephalinamide.

Prior to differential classical conditioning on two successive days, three groups of rats received an infusion (10 μg) of either the opioid peptide D-alanine2-methionine-enkephalinamide (DALA), DALA plus naltrexone (5 μg), or saline into the rostral region of the fourth ventricle. A fourth group, which served as a control to help localize DALA's site of action, received an infusion of DALA (10 μg) into the brain stem area on the floor of the ventricle. The group given DALA alone in the ventricle showed no evidence of a heart rate conditioned response (CR) either during conditioning or during a nondrug test session given 2 days after conditioning. Interference with the CR by DALA was reversed by the concomitant infusion of naltrexone. The control group given DALA in the brain stem developed a normal CR. It was suggested that DALA-induced opioid-receptor activity in the region of the periaqueductal/periventricular gray or locus coeruleus region of the ventricle may have prevented the learning of a CR. This could have occurred through a blunting of the emotional aftereffects of the unconditioned stimulus or through interference with projection pathways to other areas. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Electrophysiologic effects of quinaprilat in dogs during acute myocardial ischemia and following reperfusion

BACKGROUND: There have been few studies concerning the electrophysiologic changes associated with the use of angiotensin-converting enzyme inhibitors in patients with acute myocardial infarction. We examined the electrophysiologic effects of quinaprilat in dogs during acute myocardial ischemia and following reperfusion. METHODS: The left anterior descending coronary artery was occluded for 10 min and reperfused for 10 min. Animals received intravenous quinaprilat (3 micrograms/kg per min, quinaprilat group) or saline (control group). We measured the ventricular effective refractory period and intra-myocardial conduction time within the left anterior descending coronary artery region (ischemic region) during myocardial ischemia and following reperfusion, and determined the frequency of ventricular fibrillation. RESULTS: The effective refractory period in the ischemic region decreased during myocardial ischemia and decreased further immediately after reperfusion in the control group. The intra-myocardial conduction time in the ischemic region increased during myocardial ischemia but rapidly shortened after reperfusion in the control group. In the quinaprilat group, however, no significant differences were evident between the ischemic and non-ischemic regions in either the effective refractory period or the intra-myocardial conduction time during myocardial ischemia or following reperfusion. The percentage shortening of the effective refractory period and the percentage prolongation of the intra-myocardial conduction time in the ischemic region were significantly lower in the quinaprilat group than in the control group during myocardial ischemia and following reperfusion. The frequency of ventricular fibrillation during myocardial ischemia and following reperfusion was significantly lower in the quinaprilat group (21%) than in the control group (74%; P < 0.01). CONCLUSIONS: Quinaprilat protects against electrophysiologic abnormalities, and may decrease arrhythmias during acute myocardial ischemia and following reperfusion.     

Relation of spatial learning of rats in the Morris water maze task to the number of viable CA1 neurons following four-vessel occlusion.

Male Wistar rats were tested in the Morris water maze task 1 wk after 6, 9, or 12 min of transient global ischemia. The 9-min and 12-min ischemia groups were significantly impaired in the acquisition and the reversal experiment. A systematic counting of CA1 neurons in the whole hippocampal formation revealed a unilateral number of CA1 neurons of 286,000 in the sham group, of which two-thirds were located in the dorsal hippocampus. The ischemia groups showed a significant decline in the number of dorsal CA1 neurons, whereas only the 12-min ischemia group showed a significant but minor decline (10–25%) in the number of ventral CA1 neurons. A correlation analysis showed that the escape distance declined with increasing number of viable CA1 neurons, but poor correlation coefficients were obtained. Thus, some of the ischemic rats with even very few viable CA1 neurons in the dorsal hippocampus were capable of performing this spatial learning task at sham-group level. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Gallium-67 scanning in the differentiation of maxillary sinus carcinoma from chronic maxillary sinusitis

Gallium-67 scans of 25 patients in whom the clinical symptoms and radiographic findings were suggestive of either maxillary sinus carcinoma or chronic sinusitis proved to be valuable in the differentiation between the two disease processes. Those patients with carcinoma had positive scans, while those with sinusitis had either negative or only weakly positive scans.