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PubMed2000

Neuropsychological changes between "off" and "on" STN or GPi stimulation in Parkinson's disease.

BACKGROUND: In a previous study on a consecutive series of 62 patients with PD, the authors showed that bilateral subthalamic or pallidal continuous high-frequency deep brain stimulation (DBS) affects neither memory nor executive functions 3 to 6 months after surgery. OBJECTIVE: To investigate the specific effects of DBS by comparing the performance of patients with the stimulator turned "on" and "off." METHODS: The performance of 56 patients on clinical tests of executive function was compared after 3 and 12 months of DBS of the subthalamic nucleus (STN; n = 48) or the internal globus pallidus (GPi; n = 8) with the stimulator "on" or "off." Global intellectual efficiency, verbal learning, and mood were also evaluated with the stimulator "on." The performance of another group of 20 patients was compared after 6 months of DBS of the STN (n = 15) or the GPi (n = 5) with the stimulator "on" or "off" on more experimental tests recently shown to be more sensitive to l-dopa therapy. RESULTS: When the stimulator was "on," STN patients showed a mild but significant improvement in psychomotor speed and working memory. In comparison with the presurgical state, STN patients had no cognitive deficit at 12 months, except for lexical fluency. There was no differential effect of STN or GPi stimulation. CONCLUSIONS: 1) The specific effect of DBS seems to mimic the action of l-dopa treatment in the cognitive as in the motor domain; 2) the surgery associated with DBS does not appear to affect the cognitive performance of patients with PD 12 months later, except for a mild deficit in lexical fluency.

Adult↗

PubMed2005

Training of a minimally invasive bariatric surgeon: are laparoscopic fellowships the answer?

BACKGROUND: Fellowships in advanced laparoscopy with emphasis in laparoscopic gastric bypass (LGBP) are available for obtaining experience in performing LGBP. The following is the first report in the literature prospectively documenting a single surgeon's experience with LGBP outcomes following completion of an advanced laparoscopic surgical fellowship. METHODS: Outcomes measured prospectively included length of stay, length of operation, complications, reduction in obesity-related co-morbidities, and percentage excess weight loss. Outcomes were analyzed by quartile to see if there was difference over time. Complications were also compared to outcomes in the literature. RESULTS: 175 patients (147 female, 28 male) underwent LGBP. The mean BMI was 49.2. Mean operative time was 123 minutes, and mean length of stay was 2.2 days. The percentage excess weight loss at 1 year was 73% (n = 79). One patient developed an internal hernia (0.6%) and 1 patient developed an anastomotic leak (0.6%). Post operative transfusion rate was 4.6%. There were no deep venous thromboses or pulmonary emboli detected. There were no conversions to open, and there was no mortality. Upon quartile analysis, there was no difference in complication rates. Complication rates were comparable to published outcomes in the literature. CONCLUSION: Fellowships in advanced laparoscopy with emphasis on LGBP provide the optimal training environment for acquisition of skills necessary to safely and effectively perform LGBP. With fellowship training, complication rates were comparable to published outcomes in the literature without a period of higher complications (the learning curve).

Adult↗

PubMed1999

Medium-term results of a mobile bearing total knee replacement.

Mobile bearing total knee arthroplasty kinematically allows the advantages of large and congruent surface contact and low contact pressures, while preserving flexion, extension, and rotation in knee motion. In allowing for these degrees of freedom, the interface between bone and component also is protected from high stress. The Self Aligning I total knee arthroplasty initially was implanted in patients after its development at the authors' institution in 1990. Between 1990 and 1994, 141 patients with osteoarthritis of the knee underwent 172 total knee replacements using this system. At average followup of 5.6 years (range, 5-8 years), clinical results using this system showed a 94% satisfaction rate (good or very good). Two revision surgeries have been performed for polyethylene wear, with none of the remaining knees showing evidence of discernible wear. Complications included four cases of deep infection, four cases where a press fit femoral component failed (nonporous coated) and the patients required revision surgery, four traumatic fractures (three patellar and one supracondylar), one popliteal artery occlusion, and one revision for stiffness. Three patients required manipulation under anesthesia for arthrofibrosis. Kaplan-Meier survival curves show the probability of survival to be 91.7%, with revision surgery for any reason as an end point, and 98.8% for revision surgery because of polyethylene wear as an end point. Following the initial learning curve with this prosthesis, the medium term results using this system show maintenance of clinical success. No progressive evidence of polyethylene wear with time has been found, supporting the concept of mobile bearing arthroplasty in extending the service life of total knee arthroplasty.

Aged↗

PubMed2001

Left temporal and temporoparietal brain activity depends on depth of word encoding: a magnetoencephalographic study in healthy young subjects.

Using a 143-channel whole-head magnetoencephalograph (MEG) we recorded the temporal changes of brain activity from 26 healthy young subjects (14 females) related to shallow perceptual and deep semantic word encoding. During subsequent recognition tests, the subjects had to recognize the previously encoded words which were interspersed with new words. The resulting mean memory performances across all subjects clearly mirrored the different levels of encoding. The grand averaged event-related fields (ERFs) associated with perceptual and semantic word encoding differed significantly between 200 and 550 ms after stimulus onset mainly over left superior temporal and left superior parietal sensors. Semantic encoding elicited higher brain activity than perceptual encoding. Source localization procedures revealed that neural populations of the left temporal and temporoparietal brain areas showed different activity strengths across the whole group of subjects depending on depth of word encoding. We suggest that the higher brain activity associated with deep encoding as compared to shallow encoding was due to the involvement of more neural systems during the processing of visually presented words. Deep encoding required more energy than shallow encoding but for all that led to a better memory performance.

Adult↗

PubMed1995

Phonological computation and missing vowels: mapping lexical involvement in reading.

The role of assembled versus addressed phonology in reading was investigated by examining the size of the minimal phonological unit that is recovered in the reading process. Readers named words in unpointed Hebrew that had many or few missing vowels in their printed forms. Naming latencies were monotonically related to the number of missing vowels. Missing vowels had no effects on lexical decision latencies. These results support a strong phonological model of naming and suggest that even in deep orthographies, phonology is not retrieved from the mental lexicon as a holistic lexical unit but is initially computed by applying letter-to-phoneme computation rules. The partial phonological representation is shaped and completed through top-down activation.

Adult↗

PubMed1997

Conditioned eyeblink response is impaired in mutant mice lacking NMDA receptor subunit NR2A.

NMDA receptor channels, heteromeric assemblies of subunits with diverse subtypes, play critical roles in various kinds of synaptic plasticity underlying learning and memory. To elucidate the roles of subunits NR2A and NR2C in motor learning, we investigated acquisition of the classically conditioned eyeblink response in a delayed-conditioning paradigm by gene knockout mice. Mutant mice lacking NR2C exhibited no significant defect; however, early acquisition of the task was impaired in mutant mice lacking NR2A or both NR2A and NR2C. Based on the distribution of these subunits in brain, these results indicate that acquisition of the conditioned response does not depend on NMDA receptors in the cerebellar cortex, but that its early acquisition involves the hippocampus and/or cerebellar deep nuclei.

Animals↗

PubMed2003

Angelman syndrome: a review of the clinical and genetic aspects.

Angelman syndrome (AS) is a neurodevelopmental disorder characterised by severe learning difficulties, ataxia, a seizure disorder with a characteristic EEG, subtle dysmorphic facial features, and a happy, sociable disposition. Most children present with delay in developmental milestones and slowing of head growth during the first year of life. In the majority of cases speech does not develop. Patients with AS have a characteristic behavioural phenotype with jerky movements, frequent and sometimes inappropriate laughter, a love of water, and sleep disorder. The facial features are subtle and include a wide, smiling mouth, prominent chin, and deep set eyes. It is caused by a variety of genetic abnormalities involving the chromosome 15q11-13 region, which is subject to genomic imprinting. These include maternal deletion, paternal uniparental disomy, imprinting defects, and point mutations or small deletions within the UBE3A gene, which lies within this region. UBE3A shows tissue specific imprinting, being expressed exclusively from the maternal allele in brain. The genetic mechanisms identified so far in AS are found in 85-90% of those with the clinical phenotype and all interfere with UBE3A expression.

Angelman Syndrome↗

PubMed2003

Perioperative complications of total ankle arthroplasty.

A retrospective radiographic and chart review was performed for the initial 50 patients who underwent Agility (DePuy, Warsaw IN) total ankle arthroplasty by the senior author (M.S.M.). The review focused on the perioperative complications of nerve or tendon lacerations, intraoperative fractures, acute deep infections, wound complications and component positioning. Major wound complications were defined as those requiring a soft-tissue coverage procedure. Minor wound complications did not require soft tissue coverage and included wound breakdowns, wound edge necrosis, and superficial infections. The immediate mortise and lateral postoperative radiographs were reviewed to measure component positioning. The patients were divided into two groups to compare the initial 25 patients (Group A) with the subsequent 25 patients (Group B). There were no major wound complications in either group. Minor wound complications decreased from six in Group A to two in Group B. There were four lacerations (flexor hallucis longus, posterior tibial tendon, deep peroneal nerve, and superficial peroneal nerve), all occurring in Group A. Five patients sustained intraoperative fractures in Group A, as compared with two fractures in Group B. The number of components varying greater than 4 degrees from neutral as measured by the lateral talar, lateral tibial and mortise tibial component angles decreased by 9% from Group A to Group B. The only tibial component to be placed in more than 4 degrees of valgus occurred in Group A. It seems that a notable learning curve exists in the performance of total ankle arthroplasty as demonstrated by a comparison of the initial 25 patients with the subsequent 25 patients performed by one orthopaedic surgeon. This improvement most likely resulted from the use of enhanced techniques and further training with the prosthesis. This information can be used as a teaching tool to decrease the incidence of complications for surgeons performing their initial arthroplasties with this potentially technically demanding procedure.

Adult↗

PubMed1982

Distance cues and depth avoidance on the visual cliff.

The study tested the hypothesis that depth avoidance in chicks is a specific case of general aversion to far patterns. Using a modified visual cliff, 192 male chicks less than 24 hr. old were on one side presented vertical patterns at varying distances from the centerboard and on the other side either a shallow or deep pattern. Control data indicated that, when two vertical patterns are presented on an opaque surface, chicks will descend to the nearer pattern and that this is motivated by aversion to the far pattern rather than attraction to the near one. Further data showed, however, that when a vertical pattern appeared at varying distances on one side of the centerboard and either a shallow or deep pattern appeared on the other, chicks avoided the side with depth at all distances of the vertical pattern. Depth avoidance in chicks then is not mediated by distance cues. While these may influence descent from a centerboard to an opaque surface, avoidance of depth overrides them on the visual cliff.

Animals↗

PubMed2001

Giacomini's observations on the superficial veins of the abdominal limb and principally the external saphenous.

Carlo Giacomini, later Professor of Anatomy at the University of Turin, Italy, presented a thesis on superficial and deep lower limb venous anatomy in July 1873. This resulted in his name being associated with a vein that he described in detail that passes up deep to the fascia on the back of the thigh. However, the precise nature of his detailed and insightful observations have not previously been presented, at least for the past century. The Authors were able to find and translate the original manuscript, and the first section on the superficial veins is presented here. Giacomini documented the several variations in the origin and terminations, and anterograde and retrograde flow in this vein that have only recently been rediscovered by duplex ultrasound scanning. Much can be learned from his descriptions by all who are involved in treating chronic venous disease.

Anatomy↗

PubMed1998

New apparatus for studying behavioral thermoregulation in rats.

The operant system described here contains a box that can be convectively heated or cooled. A rat moves freely in the box. Its location is monitored photoelectrically while its deep body temperature is monitored by a telemetry system. In heat-escape experiments, hot air (40 degrees C) flows through the box. When the rat enters a reward zone the air source is switched and cold air (0 degrees C) flows through the box for a given period (30 s). Conversely, in cold-escape experiments cold air flows through the box and when the rat enters the reward zone the air source is switched to a warm one. Experiments show that rats quickly learn to stay near the reward zone and move in and out of it periodically. This system is based on behavior more natural than the frequently used lever-pressing response, and has many advantages for use in studies involving behavioral thermoregulation.

Animals↗

PubMedDate not supplied

Complication rates of diagnostic angiography performed by vascular surgeons.

The objective of this study was to compare the complication rates of diagnostic angiography performed by vascular surgeons to those previously published by interventional radiologists. From May 1999 through August 2000, 3 board-certified vascular surgeons performed 224 endovascular procedures in a modern endovascular suite. Of these 224 procedures, 144 were diagnostic angiographies. A retrospective chart review was conducted to identify periprocedural complications of these angiographies. The patients were classified into 3 groups according to the indication for angiography, and the major and overall complication rates were tabulated. The complication rates for the initial 25 and subsequent 119 arteriographies were compared to evaluate the presence of a learning curve. Thirty-eight percent of angiographies were performed to define aneurysmal anatomy (type I), 51% to define peripheral arterial stenosis or occlusion (type II), and 12% to assess symptomatic carotid artery disease or mesenteric ischemia (type III). The major complication rates for these 3 types were 0%, 2.7%, and 5.9%, respectively, and showed no statistical difference (Fischer's exact test) compared to published rates of 0.7%, 2.9%, and 9.1%. Major complications included an external iliac artery dissection, a cerebral air embolus, and a deep venous thrombosis. The overall major complication rate was 2.1%, which compares to published rates of 1.9-2.9%. The major complication rates for the initial 25 and final 119 were 8% and 0.8%, respectively. Vascular surgeons can perform diagnostic angiography with acceptable complication rates. The complication rate is reduced with angiographic experience.

Aged↗

PubMed1951

The persistence in mice of certain foreign proteins and azoprotein tracer-antigens derived from them.

Methods have been devised whereby the persistence of foreign antigens in mice can be detected. A highly diffusible, blue azo dye, echt-säure-blau was coupled to bovine gamma-globulin and human serum albumin and injected into the animals. In this way deep blue tracer antigens were obtained. These were promptly stored in cells widely distributed throughout the body, especially in the reticulo-endothelial elements of the liver, spleen and mesenteric lymph nodes. The dye as such was not stored but rapidly excreted. A blue coloration in the organs just mentioned was still perceptible after 85 to 120 days in the case of the azoglobulin and 36 to 44 days in that of the azoalbumin. To determine whether these substances had actually persisted, as well as to learn how long uncoupled globulin and albumin remained after injection, recourse was had to the phenomenon of reversed passive anaphylaxis, which was found to be characterized by extraordinary changes in the vessels of the ears (EVR) in the mouse, plainly visible under the microscope when called forth by an antiserum specific for the antigen to which the animal had been sensitized. So sensitive is the vascular response that as little as 0.5 to 0.1 microg. of protein as antigen, previously injected into the peritoneal cavity of a 30 gm. mouse, can be detected a few days later by an intravenous injection of antiserum. By means of the EVR the globulin antigen has been detected in the blood and livers of injected mice for as long as 56 and 101 days, respectively; the albumin and azoalbumin for only 21 and 36 days. In the mesenteric lymph nodes of injected mice the albumin and azoalbumin antigens were found after 42 and 44 days, respectively. The hepatic tissue and that of the mesenteric lymph nodes of mice injected with azoalbumin, containing in consequence stored blue material, when transferred to recipient mice yielded positive tests for antigen (EVR) as long as blue color could be perceived in these tissues with the unaided eye, or at low magnification. After the color had disappeared from the tissues the transfer tests were found to be negative. This fact speaks for the antigenicity of the colored material. In summary it is plain that certain antigenic proteins, after introduction into the blood stream of mice, are stored in certain tissues and that they may persist there for weeks or even months, far longer than has generally been supposed. This persistence of antigen within the body, especially after detectable amounts of antigen have apparently disappeared from the blood, provides a reason for prolonged antibody formation, a phenomenon for which no adequate explanation has hereto been offered.

Albumins↗

PubMed2006

Michigan Molecular Interactions (MiMI): putting the jigsaw puzzle together.

Protein interaction data exists in a number of repositories. Each repository has its own data format, molecule identifier and supplementary information. Michigan Molecular Interactions (MiMI) assists scientists searching through this overwhelming amount of protein interaction data. MiMI gathers data from well-known protein interaction databases and deep-merges the information. Utilizing an identity function, molecules that may have different identifiers but represent the same real-world object are merged. Thus, MiMI allows the users to retrieve information from many different databases at once, highlighting complementary and contradictory information. To help scientists judge the usefulness of a piece of data, MiMI tracks the provenance of all data. Finally, a simple yet powerful user interface aids users in their queries, and frees them from the onerous task of knowing the data format or learning a query language. MiMI allows scientists to query all data, whether corroborative or contradictory, and specify which sources to utilize. MiMI is part of the National Center for Integrative Biomedical Informatics (NCIBI) and is publicly available at: http://mimi.ncibi.org.

Databases, Protein↗

PubMed2000

Adolescent neuropsychological development after early right prefrontal cortex damage.

Adolescent development and pattern of recovery are described for a 15-year-old boy who sustained extensive right dorsolateral prefrontal cortex damage at age 7 from rupture and surgical treatment of a deep arteriovenous malformation. Follow-up evaluations at 4 years and most recently 8 years after illness have shown clear improvement in social-behavioral and almost all cognitive areas initially assessed. He demonstrated resolution of left hemispatial neglect and other visuospatial impairments in working memory, design fluency, and planning and organization. However, at the 8-year follow-up interval, an acquired form of attention deficit disorder remains evident. We hypothesized that this is the likely cause of comparatively lower scores in general intelligence, verbal learning and memory, discourse, and processing speed, that at the 4-year follow-up interval. New measures of emotional face and voice recognition showed only minor difficulties, principally in identifying vocal disgust and fear. Social and psychological maturation has continued to improve, with no evidence of developmental arrest or pervasive social impairment, although the individual is confused at times by complexities and nuances of social interaction. The pattern of findings 8 years after early right dorsolateral prefrontal cortex damage suggests remarkable recovery of primary visuospatial and social impairments, but lingering and somewhat worsening performance deficits which may be due to attentional difficulties and impulsive responding. Treatment of the attentional difficulties is currently being investigated.

Adolescent↗

PubMed1995

Anatomic basis of cognitive-emotional interactions in the primate prefrontal cortex.

Recognition that posterior basal and medial parts of the prefrontal cortex belong to the cortical component of the limbic system was important in understanding their anatomic and functional organization. In primates, the limbic system has evolved along with the neocortex and maintains strong connections with association areas. Consequently, damage to limbic structures in primates results in a series of deficits in cognitive, mnemonic and emotional processes. Limbic cortices differ in their structure and connections from the eulaminate areas. Limbic cortices issue widespread projections from their deep layers and reach eulaminate areas by terminating in layer I. By comparison, the eulaminate areas receive projections from a more restricted set of cortices and when they communicate with limbic cortices they issue projections from their upper layers and terminate in a columnar pattern. Several of the connectional and neurochemical characteristics of limbic cortices are observed as a transient feature in all areas during development. Anatomic evidence suggests that limbic areas retain some features observed in ontogeny, which may explain their great plasticity and involvement in learning and memory, but also their preferential vulnerability in several psychiatric and neurologic disorders.

Animals↗

PubMed1996

Localization of the somatostatin receptor SST2A in rat brain using a specific anti-peptide antibody.

Biological actions of somatostatin are exerted via a family of receptors, for which five genes recently have been cloned. However, none of these receptor proteins has been visualized yet in the brain. In the present-study, the regional and cellular distribution of the somatostatin sst2A receptor was investigated via immunocytochemistry in the rat central nervous system by using an antibody generated against a unique sequence of the receptor protein. Specificity of the antiserum was demonstrated by immunoblot and immunocytochemistry on rat brain membranes and/or on cells transfected with cDNA encoding the different sst receptor subtypes. In rat brain sections, sst2A receptor immunoreactivity was concentrated either in perikarya and dendrites or in axon terminals distributed throughout the neuropil. Somatodendritic labeling was most prominent in the olfactory tubercle, layers II-III of the cerebral cortex, nucleus accumbens, pyramidal cells of CA1-CA2 subfields of the hippocampus, central and cortical amygdaloid nuclei, and locus coeruleus. Labeled terminals were detected mainly in the endopiriform nucleus, deep layers of the cortex, claustrum, substantia innominata, subiculum, basolateral amygdala, medial habenula, and periaqueductal gray. Electron microscopy confirmed the association of sst2A receptors with perikarya and dendrites in the former regions and with axon terminals in the latter. These results provide the first characterization of the cellular distribution of a somatostatin receptor in mammalian brain. The widespread distribution of the sst2A receptor in cerebral cortex and limbic structures suggests that it is involved in the transduction of both pre- and postsynaptic effects of somatostatin on cognition, learning, and memory.

Animals↗

PubMed1996

Complications and failures of video-assisted thoracic surgery: experience from two centers in Asia.

BACKGROUND: There have been few specific reports on negative outcomes after video-assisted thoracic surgery. We report our combined experience from two centers in Asia. METHODS: From September 1992 to April 1995, 1,337 patients were operated on with the video-assisted thoracic surgical approach. All the patients were prospectively studied. RESULTS: There was one death (mortality rate, 0.07%) and 56 nonfatal complications: persistent air leaks (21), bleeding (6), wound infection (13), empyema (2), cerebrovascular accident (1), reexpansion pulmonary edema (2), deep vein thrombosis (1), prolonged ventilatory support (4), intercostal neuralgia (5), and port-site recurrence (1), giving rise to an overall nonfatal complication rate of 4.26%. Procedure failures consisted of 7 recurrences of spontaneous pneumothorax (of 407 cases or 1.7%); 2 recurrences of malignant pleural effusion (of 39 cases or 5.1%), and 2 local recurrences after resections for stage I lung cancers (of 41 cases or 4.9%). CONCLUSIONS: We conclude that video-assisted thoracic surgery is safe and effective for a wide range of procedures. A learning curve is present, and careful patient selection and attention to details are essential in optimizing surgical results.

Adolescent↗