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PubMed2002

Deep insight from simple models of evolution.

On one hand, people admire the often strikingly efficient results of organic evolution. On the other hand, however, they decry mutation and selection to be a rather prodigal, inefficient trial-and-error strategy. Taking into account the parallel information processing in a heterogeneous population and sexual propagation with recombination, as well as the genetic control of the reproduction accuracy, computer simulated evolution reveals a couple of interesting, sometimes surprising, properties of nature's learning-by-doing algorithm. Survival of the fittest, Spencer's résumé of Darwin's view, turns out to be a bad advice if taken literally. Individual death, forgetting, and even regression show up to be necessary ingredients of the life game. Whether the process should be named gradualistic or punctualistic, is a matter of the observer's point of view.

Algorithms↗

PubMed2001

Inactivation of the interpositus nucleus blocks the conditioned response acquired by a somatosensory conditioned stimulus in rabbit eyeblink conditioning.

1. Earlier studies suggest that the memory trace for the conditioned eyeblink reflex is formed and maintained in the interpositus nucleus (IPN) in the deep cerebellar nuclei when either an auditory or visual stimulus is used as a conditioned stimulus (CS). 2. In the present study, the eyeblink reflex of the rabbit was conditioned to a somatosensory CS (an airpuff onto the back). 3. In well-trained animals, the IPN was reversibly inactivated by local cooling and the existence of the learned responses to the CS was then tested. 4. The reversible IPN inactivation blocked the memory trace the somatosensory CS. The finding further supports the view that IPN-mediated memory trace formation is not dependent on the modality of the CS.

Animals↗

PubMed2004

International educational partnership for practice: Brazil and the United Kingdom.

BACKGROUND: To enhance healthcare globally, successful academic partnerships between institutes of higher education are crucial to strengthen collaboration between countries and identify new ways of working. The desire to reduce maternal mortality and morbidity among childbearing women in north-east Brazil urged professional nurses to seek new ways of working through such a partnership. Reflections on the success of the link identify the key qualities uniting the partnership. AIMS: This paper explores the key qualities of a higher education partnership between the United Kingdom and north-east Brazil. These qualities can act as a guide to other faculties engaged in such links to facilitate successful collaborative working for gains on both sides. RESULTS: Critical reflections from both partners revealed that the key qualities identified are effective communication, deep commitment and the need for both partners to understand each other's context of care. CONCLUSIONS: Examination of each of these qualities illustrates that the shared perspectives, mutual respect and enriched educational experience are valuable and essential to successful partnership working. This critical reflection illustrates the process of success and how others can benefit from the lessons learned, whatever the nature of partnership. Understanding the nature of collaborative working has strengthened each education and practice community, encouraged them to take risks, and remain committed to collective success.

Brazil↗

PubMed2005

Pallidal stimulation in dystonia: effects on cognition, mood, and quality of life.

Bilateral deep brain stimulation (DBS) of the globus pallidus internus (GPi) alleviates symptoms in patients with dystonia but its effects on cognition, neuropsychiatric status, and quality of life have not been examined. This is a case series report of 15 consecutive patients with different forms of dystonia who underwent bilateral implantation of DBS electrodes in the GPi. The patients were evaluated preoperatively and after 3-12 months of DBS with tests of cognition (Mattis Dementia Rating Scale, Stroop Test, Trail Making Test, Phonemic and Category Word Fluency, Digit Span, Rey Auditory Verbal Learning Test, Tonic and Phasic Alertness), neuropsychiatric status (Beck Depression and Anxiety Inventories, Montgomery Asberg Depression Rating Scale, Snaith-Hamilton Pleasure Scale, Brief Psychiatric Rating Scale), quality of life, and motor functions. GPi DBS significantly improved dystonic symptoms, functional abilities, and quality of life allowing for a significant reduction of antidystonic medications. No deterioration was observed in cognitive scores and neuropsychiatric measures. The present case series report thus provides preliminary evidence for the safety of GPi DBS regarding cognitive and neuropsychiatric functions in patients with dystonia.

Adolescent↗

PubMedDate not supplied

[Disaster planning--lessons learned from the fire disaster in Gothenburg].

The tragic fire disaster in Sweden 1998, killing 63 and wounding 213 teenagers was the result of arson fire in the basement of an overcrowded discotheque. Since the disaster occurred in a major city with substantial resources, all the injured could be hospitalised within two hours. The load on four local hospitals was initially severe due to the large number of injured. The patients suffered from inhalation injuries of different severity, whereas 25 of them also had deep skin burn injuries. Thirteen of the most severe burn injuries were transported to burn units in other parts of Sweden and to Norway. The vast psychosocial rehabilitation program initiated by health care staff, religious communions, schools and the community, has continued over the past years. This fire disaster emphasises the need for extensive preparation not only in the rescue and medical services, but also in many other areas of society.

Adolescent↗

PubMed1993

Direct projections from the anterior thalamic nuclei to the retrohippocampal region in the rat.

The present study examined the areal and laminar distribution of direct projections from the anterior thalamic nuclei to the retrohippocampal region in the rat, with anterograde transport of Phaseolus vulgaris-leucoagglutinin. The anteromedial nucleus (AM) projects to the temporal subiculum, medial entorhinal area, perirhinal area, and caudomedial part of the lateral entorhinal area. The interanteromedial nucleus (IAM) projects to the perirhinal area and the caudolateral part of the lateral entorhinal area. Furthermore, both the AM and IAM project to the temporal area 2, occipital area 1, and lateral occipital area 2. The projections from the AM and IAM to these retrohippocampal and neocortical regions terminate mainly in deep layers. The anteroventral nucleus (AV) projects to the subicular complex with a complex topographic organization. The most rostral part of the AV projects to layers I and III of the ventral presubiculum, the pyramidal cell layer of the temporal subiculum, and deep layers of the parasubiculum and medial entorhinal area. At the midrostrocaudal level of the AV, the lateral and the dorsal quadrants of the AV project, respectively, to layers I and III and to layers I and IV-VI of the ventral presubiculum, whereas the ventral and the medial quadrants project, respectively, to layers I and III and to layers I and IV-VI of the dorsal presubiculum. Furthermore, the lateral and dorsal quadrants project to the pyramidal cell layer of the temporal subiculum, whereas the ventral and medial quadrants project more septally. At the caudal third level of the AV, the dorsolateral part projects to layers I and III of the presubiculum with a patchy pattern and to the pyramidal cell layer of the septal subiculum. The anterodorsal nucleus projects mainly to deep layers of the presubiculum, parasubiculum, and entorhinal area. The results show that each subdivision of the anterior thalamic nuclei projects to a distinct field in the retrohippocampal region. This suggests that each of these projections may have a distinct modulatory influence upon the activity of retrohippocampal neurons that play important roles in limbic functioning such as memory and learning processes.

Animals↗

PubMed2005

Anatomy and histochemistry of spread-wing posture in birds. 3. Immunohistochemistry of flight muscles and the "shoulder lock" in albatrosses.

As a postural behavior, gliding and soaring flight in birds requires less energy than flapping flight. Slow tonic and slow twitch muscle fibers are specialized for sustained contraction with high fatigue resistance and are typically found in muscles associated with posture. Albatrosses are the elite of avian gliders; as such, we wanted to learn how their musculoskeletal system enables them to maintain spread-wing posture for prolonged gliding bouts. We used dissection and immunohistochemistry to evaluate muscle function for gliding flight in Laysan and Black-footed albatrosses. Albatrosses possess a locking mechanism at the shoulder composed of a tendinous sheet that extends from origin to insertion throughout the length of the deep layer of the pectoralis muscle. This fascial "strut" passively maintains horizontal wing orientation during gliding and soaring flight. A number of muscles, which likely facilitate gliding posture, are composed exclusively of slow fibers. These include Mm. coracobrachialis cranialis, extensor metacarpi radialis dorsalis, and deep pectoralis. In addition, a number of other muscles, including triceps scapularis, triceps humeralis, supracoracoideus, and extensor metacarpi radialis ventralis, were found to have populations of slow fibers. We believe that this extensive suite of uniformly slow muscles is associated with sustained gliding and is unique to birds that glide and soar for extended periods. These findings suggest that albatrosses utilize a combination of slow muscle fibers and a rigid limiting tendon for maintaining a prolonged, gliding posture.

Animals↗

PubMed2004

Immunolocalization of peroxisome proliferator-activated receptors and retinoid X receptors in the adult rat CNS.

Peroxisome proliferator-activated and retinoid X receptors (PPARs and RXRs) are transcription factors belonging to the steroid hormone receptor superfamily. Upon activation by their ligands, PPARs and RXRs bind to their target genes as heterodimers. Ligands of these receptors include lipophylic molecules, such as retinoids, fatty acids and eicosanoids, the importance of which in the metabolism and functioning of the nervous tissue is well documented. The immunohistochemical distribution of PPARs and RXRs in the CNS of the adult rat was studied by means of a sensitive biotinyl-tyramide method. All PPAR (alpha, beta/delta and gamma) and RXR (alpha, beta and gamma) isotypes were detected and found to exhibit specific patterns of localization in the different areas of the brain and spinal cord. The presence of the nuclear receptors was observed in both neuronal and glial cells. While PPAR beta/delta and RXR beta showed a widespread distribution, alpha and gamma isotypes exhibited a more restricted pattern of expression. The frontal cortex, basal ganglia, reticular formation, some cranial nerve nuclei, deep cerebellar nuclei, and cerebellar Golgi cells appeared rather rich in all studied receptors. Based on our data, we suggest that in the adult CNS, PPARs and RXRs, besides playing roles common to many other tissues, may have specific functions in regulating the expression of genes involved in neurotransmission, and therefore play roles in complex processes, such as aging, neurodegeneration, learning and memory.

Animals↗

PubMed2000

Retroperitoneal laparoscopic adrenalectomy: clinical experience in 52 procedures.

OBJECTIVES: Laparoscopic adrenalectomy has become an effective option for removal of small adrenal tumors. The aim of this prospective study was to evaluate the retroperitoneal approach with regard to intraoperative complications, morbidity, and length of hospital stay. METHODS: Between September 1996 and October 1999, we performed 52 laparoscopic adrenalectomies (31 left, 21 right) for benign lesions by a retroperitoneal approach in 44 patients (27 women, 17 men) with a mean age of 46.9 years (range 17 to 74). The average adrenal tumor size was 32 mm (range 10 to 63). All procedures required four trocars and a mean operative time of 135 minutes (range 75 to 240). RESULTS: There was no mortality, conversion rate to open surgery was 1.9%, and estimated blood loss was 80 mL (range 30 to 200). With a mean follow-up of 16 months, morbidity was 17.2%, which included intraoperative complications (5. 7%) with two vascular injuries, and postoperative complications (11. 5%) with wound infections, deep hematoma, and parietal dehiscence. Average length of hospital stay was 5 days with a mean analgesic consumption of 2 days (range 1 to 5). CONCLUSIONS: The retroperitoneal approach in laparoscopic adrenalectomy appears to be a minimally invasive and safe therapeutic option that may become the standard for unilateral or bilateral adrenal tumors not larger than 7 cm. However, a learning curve in laparoscopy is indispensable before starting this type of procedure.

Adolescent↗

PubMed1995

Undiagnosed hypercoagulable state: a case study.

Vascular nursing presents constant challenges. The natural history of vascular disease coupled with the complexity of the patient population provides an environment for constant learning. Providing care to these unique individuals demands a thorough knowledge of vascular anatomy and physiology, diagnostic interventions, treatment modalities, multidisciplinary resources, and nursing interventions. This case study explores the multifaceted realm of vascular nursing by examining the hospital course and multidisciplinary plan of care of a 22-year-old man whose hospital course began with a lower extremity deep venous thrombosis and progressed to pulmonary embolus, phlegmasia cerulea dolens, compartment syndrome, sepsis, arterial thrombosis, severe coagulopathy, priapism, laryngeal bleeding/laryngospasm, and subsequent notification of having received a unit of blood from a donor whose human immunodeficiency virus status was later determined to be positive. The intent of this article is not to define a specific means of practice but to share with colleagues the wealth of knowledge that was gained from this experience.

Adult↗

PubMed1988

[Participation of the secondary motor area of the frontal lobe of the brain in organizing postural components of human voluntary movement].

Synergies of the orthograde posture associated with voluntary movements (deep respiration or fast arm elevation) were studied in 225 patients with local verified brain lesions. Postural adjustments associated with deep respiratory movements were disturbed in patients with lesions of mainly posterior part of the inferior convolution of the frontal lobe. Postural adjustments associated with arm elevation were disturbed in patients with lesions of mainly the posterior part of the superior frontal convolution corresponding to the supplementary motor area. It is concluded that postural components of different voluntary movements requiring learning are controlled by different secondary motor areas.

Arm↗

PubMed1994

Laparoscopic-assisted colon resection. Evolution from an experimental technique to a standardized surgical procedure.

Between October 1991 and November 1992, 51 patients in the mean age 63.2 years (range 19 to 91 years) underwent laparoscopic colon resection. Indications for surgery were colon carcinoma (31), adenomatous polyps (8), diverticulitis (10) and Crohn's disease (2). In right-sided lesions an extracorporeal anastomosis and in left-sided lesions an intracorporeal anastomosis was performed using the double stapling technique. The mortality rate was 1.9% and the morbidity rate 20.5% in the laparoscopic-treated group. The conversion rate was 13.7%. Except for one anastomotic leakage in a converted patient, no anastomotic problems were encountered. The percentage of infectious complications was 11.7%. Three reinterventions were necessary for treatment of two deep subfascial abscesses and one case of localized peritonitis, caused by a small small bowel injury. The mean hospital stay was 9.1 days (range 4-29 days). In the last 13 consecutive patients, except for a urinary infection, no further post-operative morbidity was encountered. Laparoscopic-assisted colon resection has evolved in to a standardized surgical technique. Initial learning problems are solved by good patient selection, better operative logistics and awareness of the dangers and pitfalls of laparoscopic surgery.

Adult↗

PubMed2003

Thalamic stimulation for tremor. Subtle changes in episodic memory are related to stimulation per se and not to a microthalamotomy effect.

The aim of this study was to investigate the impact of unilateral deep brain stimulation (DBS) of the ventrointermediate (Vim) thalamic nucleus on neuropsychological functioning comparing stimulation-on with stimulation-off conditions. Nine patients [five patients with Parkinson's Disease (PD), two patients with essential tremor (ET) and 2 patients with multiple sclerosis (MS)] underwent comprehensive neuropsychological testing for cognitive functions, including general mental impairment, aphasia, agnosia, executive and constructional abilities, learning, memory, cognitive processing speed and attention as well as depression. The neuropsychological assessments were performed at least 6 months postoperatively (mean 9 months). Testing in the stimulation-on and stimulation-off condition was obtained within a period of 3 to 4 weeks. Unilateral DBS resulted in improvement of tremor in all patients. There were no significant differences between the stimulation-on and the stimulation-off condition with the exception of a decrement of word-recall in the short delay free-recall subtest of the Rey Auditory-Verbal Learning Test (RAVLT). Subgroup analysis indicated that the impairment in word-recall was related to left-sided thalamic stimulation. Our study confirms that chronic unilateral DBS is a safe method with regard to cognitive function. The subtle changes in episodic memory are related to stimulation per se and not to a microthalamotomy effect.

Aged↗

PubMed1992

The United States: breakthroughs and waste.

The health system of the United States is in a paradoxical position. At its best, the system is a magnet for those seeking the latest technical breakthroughs. It can offer that excellence because there have never been effective financial constraints on the imagination; the system has become a major economic frontier, at which professional and other entrepreneurs successfully seek their fortune. At the same time, the system is leaving increasing numbers of Americans frustrated and disillusioned. It is beset by excess capacity in many areas, is needlessly expensive, and often bestows unnecessary health services. Yet only the experts are aware of these flaws; most Americans still express high satisfaction with the quality of the services they receive from their doctors and hospitals. The public's major misgivings arise over the awkward and inequitable way in which American health care is financed. The typical private health insurance policy, for example, is tied to a particular job. If the job is lost, so is the health insurance. Furthermore, these policies are priced on actuarially "fair" principles, so sick individuals are forced to pay higher insurance premiums than relatively healthy ones and chronically ill persons often cannot obtain health insurance coverage at any price. Although there are public programs to catch many persons not privately insured, the coverage tends to be insufficiently extensive and deep. Some 35 million Americans, mostly poor, have no health insurance whatsoever. Unfortunately, at this time there is no political force in the United States strong enough to reform the American health system toward greater social equity and economic efficiency, whereas there are numerous groups powerful enough to block whatever reform might harm their own narrow economic interests. Other nations can learn from America's clinical and organizational innovations in health care delivery. They can also learn what not to do by studying the unseemly way in which American health care is financed.

Cost Control↗

PubMed2002

Critical appraisal--is there a need to train medical students how to read the literature?

Critical appraisal refers to the skill of reading a piece of research in a very objective and structured way. It allows for the reader to assess the quality and validity of the evidence put forward. With the emphasis on evidence-based practice in the medical profession, the ability to critically appraise the literature should be instilled into medical students. Currently, the push to encourage research shows great effort in the medical curriculum, through the incorporation of elective research programmes, by many medical institutions. But how ready are the students to even understand the research literature, let alone conduct a research? The current system throws these students into 'the deep end' of research conduct without equipping them with the tools necessary to do so. Very often this becomes a problem that snowballs through specialist training right up to the practice of medicine. The possibilities and means of introducing the skills of critical appraisal via the curriculum should be explored. In this age of self-directed and problem-based learning, a purely didactic teaching method of "how to read the literature" is surely outdated. The concept should be integrated into medical teaching, including within the implementation of the PBL system, in both the clinical and non-clinical settings, and by the introduction of the 'journal club' concept. Training of the trainers should also be considered. With the early training of critical appraisal, it can hopefully become an unconscious competence of medical graduates, who not only can produce quality research, but also able to identify quality information.

Curriculum↗

PubMed1999

Muscimol in the deep layers of the superior colliculus/mesencephalic reticular formation blocks expression but not acquisition of fear-potentiated startle in rats.

Deposits of the retrograde tracer Fluoro-Gold into the ventrolateral nucleus reticularis pontis caudalis labeled neurons in the deep layers of the superior colliculus/mesencephalic reticular formation (deep SC/Me). To test the involvement of this area in the fear-potentiated startle effect, rats were implanted with cannulas into the deep SC/Me and trained for fear-potentiated startle after infusion of the GABA(A) agonist muscimol (0.1 microg/0.5 microl). Two days later, they were tested for fear-potentiated startle. Rats then received a 2nd training session without any infusions, and 2 days later they were reinfused with muscimol (0.1 microg/0.5 microl) and tested for fear-potentiated startle. Local infusion of muscimol into the deep SC/Me completely blocked the expression but not the acquisition of fear-potentiated startle. These results indicate that a synapse in the midbrain is critical for the expression of fear-potentiated startle.

Animals↗

PubMed1995

Plasticity of inhibitory synapses in the brain: a possible memory mechanism that has been overlooked.

Long-term modification of transmission efficacy at inhibitory synapses has recently been discovered in several regions of the vertebrate brain, i.e. Mauthner cells of the goldfish, cerebellar Purkinje cells, deep cerebellar nuclei and the visual cortex. Synaptic plasticity at inhibitory synapses has properties similar to that of excitatory synapses, such as dependency on intracellular Ca2+ levels, input specificity, saturation and associativity. Considering the ubiquitous distribution of inhibitory synapses and the receptors for inhibitory transmitters, GABA and glycine, plasticity of inhibitory synapses may exist widely throughout the brain. It may contribute to learning and development in concert with plasticity of excitatory synapses.

Animals↗

PubMed2026

Leveraging Interradiomic Feature Relationships for Enhanced Prediction of Distant Metastasis and Characterization of Heterogeneity in Head and Neck Cancer.

PURPOSE: Distant metastasis remains a major cause of treatment failure in head and neck (HN) cancer, highlighting the need for more accurate early risk stratification. This study developed and validated a deep radiomics framework to characterize tumor heterogeneity from pretreatment computed tomography (CT) images and improve prediction of distant metastasis-free survival (DMFS). METHODS AND MATERIALS: This multicenter study included 3421 patients with HN cancer from 4 cohorts across 12 institutions. Radiomics features were extracted from primary tumors and transformed into OmicsMaps, a structured representation that spatially organizes interfeature relationships to facilitate learning of complex prognostic patterns. A convolutional neural network was trained to derive prognostic signatures, which were integrated with key clinical variables to construct an OmicsMap-clinical fusion model for patient risk stratification. Model performance was assessed using the concordance index (C-index) and time-dependent area under the receiver operating characteristic curve (AUC) in the CT Images from Large Head and Neck Cohort (RADCURE), HEAD-NECK-RADIOMICS-HN1 (HN1), and Head-Neck-Positron Emission Tomography-Computed Tomography (HN-PET-CT) cohorts. Radiogenomic analyses using RNA-seq data were conducted in the Cancer Genome Atlas Head-Neck Squamous Cell Carcinoma (TCGA-HNSC) cohort to investigate biological characteristics associated with the imaging-defined risk groups. RESULTS: The OmicsMap achieved C-index values of 0.742, 0.768, and 0.671 in the RADCURE, HN1, and HN-PET-CT cohorts, outperforming the conventional radiomics approach by 5.40%-6.37%. Incorporating clinical variables further improved generalizability, yielding a C-index of 0.864 (HN1) and 0.730 (HN-PET-CT), with time-dependent AUC of 0.727-0.895. The fusion model consistently stratified patients into distinct high- and low-risk groups for both DMFS and overall survival across cohorts (P <.01). Radiogenomic analyses revealed enrichment of immune-related pathways in the low-risk group, whereas the high-risk group exhibited a more aggressive phenotype enriched for proliferation, hypoxia, and epithelial-mesenchymal transition pathways, along with a fibrosis-prone tumor microenvironment characterized by extracellular matrix remodeling. CONCLUSIONS: Modeling interradiomic feature relationships using the OmicsMap representation substantially improves CT-based prediction of DMFS and characterization of tumor heterogeneity in HN cancer, supporting precision risk stratification in clinical oncology.

Journal Article↗