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PubMed2002

Learning approaches and learning difficulties: a comparison of Indian and Nepali dental science students.

This study explored the difference in learning approaches and difficulties of Nepali and Indian undergraduate students of dental science. A locally developed inventory was used to measure learning approach and learning difficulties. Data collected from 166 Indians and 69 Nepalis were compared. The scores on various scales of the inventory indicate that Nepalis are more fearful and less confident regarding examination and course completion and have significantly less positive perception about academic capability. Indian students scored significantly higher on motivation, interest, and deep processing. The language problem was significantly greater for Nepali students. Higher percentages of Nepalis experienced various academic and nonacademic problems. The study highlights the need to consider difference in learning approach among the students of health science courses that admit students from different academic, nonacademic, and cultural backgrounds.

Analysis of Variance↗

PubMed2004

The effects of ethanol on the developing cerebellum and eyeblink classical conditioning.

In rats, developmental ethanol exposure has been used to model the central nervous system deficits associated with human fetal alcohol syndrome. Binge-like ethanol exposure of neonatal rats depletes cells in the cerebellum, including Purkinje cells, granule cells, and deep nuclear cells, and produces deficits in simple tests of motor coordination. However, the extent to which anatomical damage is related to behavioral deficits has been difficult to estimate. Eyeblink classical conditioning is known to engage a discrete brain stem-cerebellar circuit, making it an ideal test of cerebellar functional integrity after developmental ethanol exposure. Eyeblink conditioning is a simple form of motor learning in which a neutral stimulus (such as a tone) comes to elicit an eyeblink when repeatedly paired with a stimulus that evokes an eyeblink prior to training (such as mild periorbital stimulation). In eyeblink conditioning, one of the deep cerebellar nuclei, the interpositus nucleus, as well as specific Purkinje cell populations, are sites of convergence for tone conditioned stimulus and somatosensory unconditioned stimulus information, and, together with brain stem nuclei, provide the necessary and sufficient substrate for the learned response. A series of studies have shown that eyeblink conditioning is impaired in both weanling and adult rats given binge-like exposure to ethanol as neonates. In addition, interpositus nucleus neurons from ethanol-exposed rats showed impaired activation during eyeblink conditioning. These deficits are accompanied by a permanent reduction In the deep cerebellar nuclear cell population. Because particular cerebellar cell populations are utilized in well-defined ways during eyeblink conditioning, conclusions regarding the underlying neural substrates of behavioral change after developmental ethanol exposure are greatly strengthened.

Animals↗

PubMed2001

Student learning and the teaching-research nexus in oral biology.

Although frequently coexistent, we know little about the interactions among research, teaching and learning in higher education. This study examines the preferences of second and third year dental students for questions that require a research-based deep approach or questions that require a straightforward didactic approach. A questionnaire was designed to evaluate the opinion of 114 students who took part in the Oral Biology course. 56 second year students (75%) responded while 58 (84%) of third year students responded. Questions that required an interpretive approach were found to be most appealing by 70.2% of all students. Questions which required a regurgitative approach were favoured by 11.6% of students. No significant differences were found when the sample was broken down by country of origin, year of study or gender, suggesting that dental students preferred research-based learning rather than superficial didactic learning.

Attitude↗

PubMed2003

[Apomorphine hyperpigmentation].

A 72 year old bedridden, disoriented man presented with a continuously increasing number of blue nodules on his abdomen and both thighs. In addition, he had a melanoma on his left forearm (SSM, Clark level III, Breslow 0.75 mm), which lead to the clinical diagnosis of melanoma metastases. Biopsy of one of the blue nodules showed CD68 positive histiocytic cells loaded with brownish pigment granules and a lymphocytic infiltrate within the deep dermis and upper subcutis. The pigment reacted histochemically similarly to melanin. Melanocytes were absent at these sites. Because of the unexplained clinical and histopathological picture, the patient's history was reassessed and it was learned that the patient had received subcutaneous infusions of apomorphine for the past 10 years for the treatment of Parkinson's disease. By oxidation, apomorphine may be converted into tetrahydroisoquinoline-melanin, which apparently is the cause for the accumulation of pigment within the deep dermis.

ADP-ribosyl Cyclase↗

PubMed2002

Sleep-dependent hippocampal slow activity correlates with waking memory performance in humans.

The positive effect of postlearning sleep on memory consolidation as well as the relationship between sleep-related memory processes and the hippocampal formation are increasingly clarified topics in neurobiology. However, the possibility of a stable relationship between waking mnemonic performance and sleep-dependent hippocampal electric activity is unexplored. Here we report a correlative analysis between sleep-dependent parahippocampal-hippocampal (pHip-Hip) electric activity recorded by foramen ovale (FO) electrodes and different types of memory performances in epileptic patients. Psychological testing was performed days or weeks before electrophysiological recordings. The relative spectral power of the slow activity (below 1.25 Hz) during deep non-REM (NREM) sleep at the right pHip-Hip region correlated positively with the visual memory performance according to Rey-Osterrieth Complex Figure Test (ROCFT). Along the posterior-anterior direction of the hippocampal formation a linear increasing of correlations was observed. The relative power of the activity below 1.25 Hz at the left pHip-Hip during phasic REM sleep correlated positively with verbal learning performance and mnemonic retention values according to ROCFT. It is concluded that the pHip-Hip structures' capacity of producing high amplitude and synchronized slow (< 1 Hz) oscillation during deep NREM sleep is related to the functional power of these structures. We hypothesize that the asymmetric (side-specific) propagation of ponto-geniculo-occipital (PGO) activity to the pHip-Hip region is related to the memory correlates of phasic REM sleep.

Adult↗

PubMed1978

[Effect of right-sided hippocampotomy on memory and learning ability].

The authors report the results of memory and learning ability investigations in a patient treated with hippocampotomy (uncotomy) for severe epileptic seizures. In the seeg investigations the changes were most pronounced in the hippocampus. In psychological investigations before the operation deep disturbances of verbal memory with unchanged (normal) level of mental efficiency were found. After stereotaxic treatment epileptic seizures disappeared completely, the patient completed a vocational school and started working. Follow up examinations during 6 years after the operation failed to demonstrate any decrease in mental efficiency. The impairment of verbal memory and learning ability was decreased significantly.

Child↗

PubMed1997

Cerebellar circuits and synaptic mechanisms involved in classical eyeblink conditioning.

There is increasing evidence that, in addition to its major functional role in the regulation of fine motor control, the cerebellum is involved in other important functions, such as sensory-motor learning and memory. Classical conditioning of the eyeblink or nictitating membrane response (and other discrete behavioral responses) is a form of sensory-motor learning that depends crucially upon the cerebellum. Within the cerebellum, however, the relative importance of the cerebellar cortex and the deep cerebellar nuclei in eyeblink conditioning is unclear and disputed. Recent studies employing various mutant mice provide an effective approach to resolving this controversy. Eyeblink conditioning in spontaneous mutant mice deficit in Purkinje cells, the exclusive output neurons of the cerebellar cortex, indicate that both the cerebellar cortex and the interpositus nucleus are important. Furthermore, studies involving gene knockout mice suggest that long-term depression, a process of synaptic plasticity occurring in Purkinje cells, might be involved in eyeblink conditioning.

Animals↗

PubMed1989

Learning to care--a qualitative perspective of student evaluation.

There is a school reform going on in nursing education in Finland, which emphasizes all qualitative aspects of learning. The purpose of this study was to examine the qualitative evaluation of student performance, with the final examination of nursing education taken as an example. The objective was to develop methods to "measure" the depth of the learning process in nursing education. The data consisted of the students' answers to the final exam questions (N = 418). The answers were those of the surgical and psychiatric nursing students in Finland in 1985. Data was analyzed by the method of discursive content analysis. For describing the cognitive complexity of the knowledge, the concepts of the level of information processing (surface-deep), the form of the knowledge (atomistic-holistic), and the structure of the knowledge (pre-structured--relating) were used. In the students' answers, a tendency towards superficial cognitive learning and the production of fragmentary information without a basic learning idea can be seen.

Cognition↗

PubMed1996

A learned odor decreases the number of Fos-immunopositive granule cells in the olfactory bulb of young rats.

Olfactory stimulation evokes a column of activity within the olfactory bulb extending from the glomerular layer to the granule cell layer that can be visualized with 2-deoxyglucose autoradiography, optical imaging, Fos protein immunohistochemistry and c-fos mRNA in situ hybridization. The Fos response to odors is typified by the activity of relatively few juxtaglomerular cells, which often occur in foci, and a large number of granule cells extending through much of the bulb. In this study, we characterized the granule cell response to an odor for which young rats had acquired a preference. Fos-like immunoreactive granule cells were quantified by image analysis, and densely stained cells were counted in a region previously shown to be responsive to peppermint odor. We found that odor-trained pups have about half the number of Fos-immunopositive superficial granule cells which respond to a learned odor than do control pups. We then determined whether there was a correlation between the juxtaglomerular cell response and the response of the superficial granule cells deep to those glomerular layer cells. We found a positive correlation between the number of juxtaglomerular cells and the number of granule cells demonstrating Fos immunoreactivity in both control and trained pups, a relationship that changed with early olfactory training.

Animals↗

PubMed2004

Arabidopsis to rice. Applying knowledge from a weed to enhance our understanding of a crop species.

Although Arabidopsis is well established as the premiere model species in plant biology, rice (Oryza sativa) is moving up fast as the second-best model organism. In addition to the availability of large sets of genetic, molecular, and genomic resources, two features make rice attractive as a model species: it represents the taxonomically distinct monocots and is a crop species. Plant structural genomics was pioneered on a genome-scale in Arabidopsis and the lessons learned from these efforts were not lost on rice. Indeed, the sequence and annotation of the rice genome has been greatly accelerated by method improvements made in Arabidopsis. For example, the value of full-length cDNA clones and deep expressed sequence tag resources, obtained in Arabidopsis primarily after release of the complete genome, has been recognized by the rice genomics community. For rice >250,000 expressed sequence tags and 28,000 full-length cDNA sequences are available prior to the completion of the genome sequence. With respect to tools for Arabidopsis functional genomics, deep sequence-tagged lines, inexpensive spotted oligonucleotide arrays, and a near-complete whole genome Affymetrix array are publicly available. The development of similar functional genomics resources for rice is in progress that for the most part has been more streamlined based on lessons learned from Arabidopsis. Genomic resource development has been essential to set the stage for hypothesis-driven research, and Arabidopsis continues to provide paradigms for testing in rice to assess function across taxonomic divisions and in a crop species.

Arabidopsis↗

PubMed2001

Long-term adaptation to dynamics of reaching movements: a PET study.

Positron emission tomography (PET) was used to examine changes in the cerebellum as subjects learned to make movements with their right arm while holding the handle of a robot that produced a force field. Brain images were acquired during learning and then during recall at 2 and 4 weeks. We also acquired images during a control task where the force field was not learnable and subjects did not show any improvements across sessions. During the 1st day, we observed that motor errors decreased from the control condition to the learning condition. However, regional cerebral blood flow (rCBF) in the posterior region of the right cerebellar cortex initially increased from the control condition and then gradually declined with reductions in motor error. Correspondingly, rCBF in the ipsilateral deep cerebellar nuclei (DCN) initially decreased from the control condition and then increased with reductions in motor error. If measures of rCBF mainly reflect presynaptic activity of neurons, this result predicts that DCN neurons fire with a pattern that starts high in the control task then decreases as learning proceeds. Similarly, Purkinje cells should generally have their lowest activity in the control task. This pattern is consistent with neurophysiological recordings that find that cerebellar activity during early learning of a motor task may mainly reflect changes in coactivation of muscles of the limbs, rather than a learning specific signal. By the end of the first session, motor errors had reached a minimum and no further improvements were observed. However, across the weeks a region in the anterior cerebellar cortex showed gradual decreases in rCBF that could not be attributed to changes in motor performance. Because patterns of rCBF in the cortex and nuclei were highly anti-correlated, we used structural equation modeling to estimate how synaptic activity in the cerebellar cortex influenced synaptic activity in the DCN. We found a negative correlation with a strength that significantly increased during the 4 weeks. This suggests that, during long-term recall, the same input to the cerebellar cortex would produce less synaptic activity at the DCN, possibly because of reduced cerebellar cortex output to the DCN.

Adaptation, Biological↗

PubMed1993

Significance of computed tomography-measured volume in the prognosis of cervical carcinoma.

BACKGROUND: Computed tomography (CT) can visualize the volume and shapes of the deep-seated tumors and is expected to predict the treatment outcome in a more quantitative manner. This study was undertaken to learn the prognostic significance of CT-provided information in the radiation therapy of carcinoma of the cervix. METHODS: One hundred thirty-one CT evaluations were systematically applied to 87 patients having carcinoma of the cervix uteri. The cervical mass volume was measured by CT at a certain phase or phases of treatment and was analyzed in relation to their local control at 3 years and the survival at 5 years. RESULTS: The initial volume, measured at the beginning of radiation therapy, was not a significant prognostic guide for the local control. However, the second volume, the volume of cervical lesion measured immediately after the completion of external irradiation, proved to be a prominent prognostic factor for both the 3-year local control and 5-year survival, regardless of the clinical stage. In 52 patients whose second volume was less than 38 cm3, 47 patients (90.4%) were locally controlled for 3 years or more after radiation therapy, whereas 17 of 23 patients (73.9%) whose second volume exceeded 38 cm3 failed in the local control. Five-year actuarial survival rate was 53.1% plus or minus 6.2% in the former group and 26.1% plus or minus 9.6% in the latter group. CONCLUSIONS: CT-aided volumetry provides for an early prediction of treatment failure in radiation therapy for cervical carcinoma.

Actuarial Analysis↗

PubMed2006

Challenges of biological realism and validation in simulation-based medical education.

OVERVIEW: Simulation, both physical and computer-based, has a rich history in support of medical education. Essentially all these efforts have been aimed at instilling concrete measurable skills, akin to vocational training. They present learners with choices, facilitating a degree of learning by doing. The sets of learner choices are usually limited, with choices clearly classified into "right" and "wrong". But much of medicine is not much like a multiple-choice test. The realm of choices is broad and not always easily converted to a short list. The "correct" answer is not always known by the experienced physician beforehand, sometimes not even after the die is cast and the future unfolds. Computer simulation of human disease and its treatment can in principle be tremendously useful in the education of both basic and clinical scientists. This paper describes some challenges in the construction of simulation-based "liberal arts" biomedical education. OBJECTIVES: The educator attempting to develop a learning environment based on simulation of biology faces some special challenges. The challenges addressed in this paper are: face validity and deep validity; finding the right degree of realism; authoring biomedical models efficiently; managing randomness. To illustrate the issues, we trace the history of the Oncology Thinking Cap throughout several versions and expansions of educational objectives, and describe the detection and remediation of shortcomings related to these issues. DESIGN: Dealing effectively with issues of validity and realism can be accomplished if the acquisition of information driving and justifying the model development choices is documented, preferably automatically, during the process. Efficiency in authoring is greatly enhanced by judicious modularity to encourage re-use, and by the use of templated statements rather than raw code or exotic graphical components to represent the instructions driving the model. Randomness can be used to familiarize learners with the true relative proportions of types of cases, or to enrich the encountered cases with rarer but more instructive cases. When a learner repeats an encounter with a scenario while changing a single option, proper management of randomness is essential to avoid artifacts of random number generators. Otherwise an outcome change caused by a shift in random number streams may masquerade as an outcome change due to the changed option. CONCLUSION: Effective use of computer simulation of human disease and its treatment for biomedical education faces daunting obstacles, but these problems can be solved.

Computer Simulation↗

PubMed2026

Sequence optimization targeting mRNA stability enhances monoclonal antibody titers in CHO cells.

This study presents a DNA sequence optimization approach that integrates mRNA stability as a tunable design parameter to enhance monoclonal antibody expression in Chinese hamster ovary (CHO) cells. A comprehensive combinatorial library of synonymous coding-sequence variants of an IgG1 light chain was integrated as single copies at a defined genomic locus in CHO cells with identical regulatory elements. Steady-state mRNA abundance, quantified by deep sequencing of gDNA and mRNA, served as a proxy for mRNA stability. These data were used to train a machine learning model that predicts mRNA abundance from coding sequence using embeddings from a pre-trained nucleotide transformer. This abundance predictor, together with established translational metrics, was incorporated into a genetic algorithm for multi-objective codon optimization. As proof-of-concept, we optimized sequences encoding Trastuzumab to either maximize or minimize the abundance criterion and obtained benchmark sequences from two commercial providers. Using targeted integration, we generated CHO cell lines and measured protein titer and cell-specific productivity. Sequences optimized for high abundance significantly increased intracellular mRNA levels (+41%), protein titer (+59%), and cell-specific productivity (+85%) relative to low-abundance designs, while viable cell densities remained comparable. Compared to commercial benchmarks, high-abundance sequences achieved significantly higher titer (+70%) and cell-specific productivity (+98%). These findings establish mRNA stability as a practical and complementary design parameter for codon optimization in monoclonal antibody production, with potential applicability to other proteins and expression systems.

CHO↗

PubMed1988

Recent advances in the management of venous thromboembolism.

Deep venous thrombosis and pulmonary embolism are frequently diagnosed in patients encountered in a primary-care practice. In the past 10 years, many important advances have been made regarding the management of these disorders. Risk factors have been better defined than in the past. Several new prophylactic measures--such as external pneumatic compression of the lower extremities, dihydroergotamine in combination with heparin, adjusted-dose heparin, and two-step warfarin therapy--can be used to help prevent deep venous thrombosis in surgical patients. The use of serial impedance plethysmography has expanded options for noninvasive diagnosis of deep venous thrombosis. Correlations between pulmonary embolism and ventilation-perfusion lung scan patterns have been clarified. Although much has been learned about heparin and warfarin that affect common management decisions, the indications for thrombolytic therapy for venous thromboembolism remain controversial. Finally, studies have shown that calf vein thrombi that are not detectable by impedance plethysmography and that show no evidence of proximal propagation by serial impedance plethysmography do not require treatment.

Anticoagulants↗

PubMedDate not supplied

Survey of tourniquet use in podiatric surgery.

Tourniquet use in foot and ankle surgery is common practice; however, the technique varies among foot and ankle surgeons and there are no standard guidelines. To analyze trends in foot and ankle tourniquet use, the authors conducted an e-mail survey. One thousand six hundred sixty-five foot and ankle surgeons were sent a tourniquet-use survey via e-mail, across Canada and the United States. Nineteen percent of the recipients completed and returned the surveys. Eleven (3.4%) rarely or never use a tourniquet and 8 (2.5%) use an Esmarch bandage tourniquet at the ankle. Most use pneumatic ankle cuffs (92% use, 27% use exclusively); many also use thigh cuffs (69%) and some also use calf cuffs (15%). Most thigh-cuff users (62%) experience problems with cuff fit sometimes or often. All but 3 respondents exsanguinate the limb before tourniquet inflation. Specific devices used for exsanguination varied among surgeons. Most commonly used tourniquet pressures range from </=200 to 350 mm Hg at the ankle and </=200 to >/=351 mm Hg for the thigh (64% use pressures between 301 and 350 mm Hg). Only 7% of respondents consider limb occlusion pressure when selecting tourniquet cuff pressure. Based on published studies of limb occlusion pressures, these ranges suggest that some of the more common pressure settings may be higher than necessary for many patients. Vascular disease or previous bypass (91%) and deep vein thrombosis (83%) were the most commonly listed contraindications to tourniquet use. Approximately 10% of respondents have either experienced or learned of skin and nerve injuries secondary to lower extremity tourniquet use at any level. The varied responses show a lack of overall consensus on tourniquet pressure settings. Guidelines for optimizing cuff pressure and technique should be established to minimize the risk of complications.

Ankle↗

PubMed2002

Cerebellar cortical inhibition and classical eyeblink conditioning.

The cerebellum is considered a brain structure in which memories for learned motor responses (e.g., conditioned eyeblink responses) are stored. Within the cerebellum, however, the relative importance of the cortex and the deep nuclei in motor learning/memory is not entirely clear. In this study, we show that the cerebellar cortex exerts both basal and stimulus-activated inhibition to the deep nuclei. Sequential application of a gamma-aminobutyric acid type A receptor (GABA(A)R) agonist and a noncompetitive GABA(A)R antagonist allows selective blockade of stimulus-activated inhibition. By using the same sequential agonist and antagonist methods in behaving animals, we demonstrate that the conditioned response (CR) expression and timing are completely dissociable and involve different inhibitory inputs; although the basal inhibition modulates CR expression, the conditioned stimulus-activated inhibition is required for the proper timing of the CR. In addition, complete blockade of cerebellar deep nuclear GABA(A)Rs prevents CR acquisition. Together, these results suggest that different aspects of the memories for eyeblink CRs are encoded in the cerebellar cortex and the cerebellar deep nuclei.

Action Potentials↗

PubMed2001

Developmental dyslexia: an update on genes, brains, and environments.

The science of reading and developmental dyslexia has experienced spectacular advances during the last few years. Five aspects of this research are discussed in the article. (1) The holistic phenomenon of reading is complex. Many lower-level psychological processes (e.g., phonemic awareness, phonological decoding, ability to process stimuli rapidly and automatize this process, memory, ability to recognize words) contribute to a single act of reading. Conceptualizing the complex process of reading through its partly overlapping but partly independent components--which contribute to, but do not fully explain, the holistic process of reading--provides an excellent model for understanding complex hierarchies of higher mental functions. Those who master reading skills successfully and those who have difficulties doing so differ in a wide range of reading-related processes. The central deficit experienced by poor readers appears to be related to phonological processing (a complex hierarchy of functions related to processing phonemes), whereas characteristics of automatization processes seem to moderate the reading outcome for people whose phonological skills are weak. (2) There are new data addressing models of dyslexia in languages other than English. The most fascinating finding is that the model implicating phonological deficit as central to dyslexia, and the lack of ability to automatize as leading to troubled reading, appears to be universal, regardless of the specific language. However, there is an interaction effect between the characteristics of a particular language and the developmental model of dyslexia. In phonologically more difficult languages (e.g., English), the most pronounced weakness appears to occur in phonological processing, whereas in phonologically easier languages (e.g., German), the crucial role in the manifestation of dyslexia is played by the lack of the skills needed to achieve automatization. (3) There is abundant evidence that reading (i.e., any single act of reading as well as reading as a holistic process) is "cooked" by the brain. Although no unified brain map of reading has been developed, some specific areas of the brain have been implicated in different reading-related cognitive processes by different laboratories and on different samples. (4) Indisputable evidence has been accumulated suggesting the involvement of the genome in developmental dyslexia. As of now, specific regions of the genome have been identified as being intimately involved with a number of different reading-related processes. Today the field of developmental dyslexia is the only area of genetic studies of human abilities and disabilities in which linkages to the genome have been robustly replicated in independent laboratories. (5) Finally, evidence suggests that developmental dyslexia might be only one of the manifestations of a deep, underlying, anatomical syndrome. The comorbidity of developmental dyslexia with both internalizing and externalizing behavioral disturbances, as well as with other learning disabilities, underscores the need for wide-ranging cognitive and behavioral approaches in the remediation programs offered to dyslexic children.

Adolescent↗