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PubMed2000

Neuromuscular specializations of the pharyngeal dilator muscles: II. Compartmentalization of the canine genioglossus muscle.

The genioglossus (GG) muscle is divided into horizontal and oblique compartments that are the main protrusor and depressor muscles of the tongue, respectively. In humans the GG plays an important role in speech articulation, swallowing, and inspiratory dilation of the pharynx. At present, little is known about the neuromuscular specializations of the GG in any mammal. This study examined the specializations of these compartments in the canine tongue using a variety of anatomical and histochemical techniques. Six canine GG muscles were sectioned and stained for myofibrillar ATPase to study muscle fiber types; five whole-mount GG muscles were stained for acetylcholinesterase (AChE) to study the distribution of motor endplates; and eight whole mount GG muscles were processed with Sihler's stain to study the entire nerve supply pattern. In addition, the arrangement of muscle fibers of the GG within the tongue was also determined (N = 3). The most notable difference between the compartments of the GG was their proportions of fast and slow twitch muscle fibers: the horizontal compartment contained 64% slow twitch muscle fibers compared to 41% in the oblique compartment. In addition, although the oblique compartment appeared to be grossly homogeneous, it could be divided into thirds by significant differences in the percentages of slow twitch fibers: posterior (23%), middle (15%), and anterior (56%; P < 0.05). The muscle fibers of the oblique GG within the tongue were found to be divided into medial and lateral layers that run vertically and transversely, respectively. The nerve supply to each third of the oblique GG formed a plexus with the anterior third being the densest. The innervation pattern of the oblique GG was also notable as terminal nerve branches coursing parallel to the muscle fascicles gave off perpendicular secondary branches along each motor endplate band. These secondary nerve branches connected the primary nerves and formed a regularly spaced grid throughout the compartment. Evidently, the two compartments of the GG exhibited different anatomical specializations. The horizontal had a slow muscle fiber profile and simple innervation pattern; these qualities are possibly related to its single force vector and respiratory related activity. The oblique compartment had a relatively fast muscle fiber profile with evidence for three separate functional subdivisions. The most anterior part was noticeably different, and was presumably specialized for fine motor control of the tip of the tongue. The vertically oriented fibers of the oblique GG within the tongue body may function as a midline depressor of the tongue, whereas its transversely oriented fibers could play a role in narrowing the tongue during other motor tasks.

Acetylcholinesterase↗
PubMed2004

Evolution of the special senses in primates: past, present, and future.

The present special issue of The Anatomical Record is the result of a symposium entitled Evolution of the Special Senses in Primates. Considered together, the special senses of primates are remarkable because they constitute a singular and definitive suite of mammalian characteristics. Examining their evolution is pivotal for understanding the origin and present-day variation of primate behavior and ecology. Accordingly, the 14 articles assembled here consider the different constraints and opportunities associated with the uptake and use of physical and chemical stimuli. The present issue brings together experts on different primate sensory modalities and stresses events at the sensory periphery, where the organism is exposed to and comes into contact with its environment. Key topics include color vision, the genetics of olfaction, the morphological basis and significance of chemical communication, and the neural organization and scaling of primate sensory systems. The result is a special issue that both reflects our current understanding of primate sensory modalities and challenges certain fundamental assumptions concerning their evolution.

Animals↗
PubMed2005

Specialization in pyramidal cell structure in the sensory-motor cortex of the Chacma baboon (Papio ursinus) with comparative notes on macaque and vervet monkeys.

The systematic study of pyramidal cell structure has revealed new insights into specialization of the phenotype in the primate cerebral cortex. Regional specialization in the neuronal phenotype may influence patterns of connectivity and the computational abilities of the circuits they compose. The comparative study of pyramidal cells in homologous cortical areas is beginning to yield data on the evolution and development of such specialized circuitry in the primate cerebral cortex. Recently, we have focused our efforts on sensory-motor cortex. Based on our intracellular injection methodology, we have demonstrated a progressive increase in the size of, the branching structure in, and the spine density of the basal dendritic trees of pyramidal cells through somatosensory areas 3b, 1, 2, 5, and 7 in the macaque and vervet monkeys. In addition, we have shown that pyramidal cells in premotor area 6 are larger, more branched, and more spinous than those in the primary motor cortex (MI or area 4) in the macaque monkey, vervet monkey, and baboon. Here we expand the basis for comparison by studying the basal dendritic trees of layer III pyramidal cells in these same sensory-motor areas in the chacma baboon. The baboon was selected because it has a larger cerebral cortex than either the macaque or vervet monkeys; motor cortex has expanded disproportionately in these three species; and motor cortex in the baboon reportedly has differentiated to include a new cortical area not present in either the macaque or vervet monkeys. We found, as in monkeys, a progressive increase in the morphological complexity of pyramidal cells through areas 3b, 5, and 7, as well as from area 4 to area 6, suggesting that areal specialization in microcircuitry was likely to be present in a common ancestor of primates. In addition, we found subtle differences in the extent of the interareal differences in pyramidal cell structure between homologous cortical areas in the three species.

Animals↗
PubMed2001

The use of trial leave for restricted special hospital patients.

INTRODUCTION: For England and Wales, Section 17 of the Mental Health Act 1983 allows for compulsorily detained patients to have trial leave (TL) between hospitals or from hospital to community to allow a period of testing readiness for a change in residency and/or legal status. The aim of this study was to document the use of TL for the largest sub-group of such patients within two discharge cohorts from one high security hospital and to test for correlates. METHOD: Data were collected from the special hospitals' case register for two Broadmoor Hospital discharge cohorts, 1984 and 1990-94, of offender patients with hospital orders under Home Office restrictions on discharge (Section 37/41). RESULTS: In 1984, only two of the 29 people leaving special hospital did so under trial leave arrangements, but by 1990 to 1994, 71% of restricted hospital order departures were under trial leave (92/130), a significant change in practice. Focusing on only the later cohort, women were disproportionately more likely to leave in this way. Trial leave was used more for patients with an index offence of homicide, similarly for violent offences but less so for sex offences. Nature of disorder did not have any bearing on the use of trial leave. Use of trial leave did not significantly shorten length of stay within the special hospital. CONCLUSION: Trial leave has become the most usual route out of special hospital, and is the departure route used almost exclusively for women patients, yet there appears to be no obvious advantage for the patient in shortening length of stay in high security. However, there is no way of knowing how long patients would have stayed had the option of trial leave not been available to them. Furthermore, no advantage for the public was found in the preferential use of TL for discharges to the community.

Journal Article↗
PubMed1978

Development of the diencephalon in the rat. III. Ontogeny of the specialized ventricular linings of the hypothalamic third ventricle.

The development of the specialized linings of the hypothalamic third ventricle was examined autoradiographically in mature rats that were labelled with 3H-thymidine during the developmental period, and in a closely spaced series of embryonic and infant rats. We distinguished in mature rats, apart from the typical ependymal wall, three specialized linings: the convoluted ependyma, the laminated epithelium, and the tanycytic epithelium. The ventricular wall of most of the anterior hypothalamus, and of the dorsal portion of the posterior hypothalamus, is composed of ciliated ependymal cells and most of them are generated several days before birth, soon after the cessation of neurogenesis in the adjacent hypothalamic nuclei. The cells of the rostral convoluted ependyma adjacent to the paraventricular nucleus are produced at about the same time as the neighboring cells of the smooth ependyma. Its cells come from the same germinal region that we have assumed to generate the neurons of the magnocellular neurohypophysial secretory system. The structural differentiation of the convoluted ependyma starts after birth and is completed by the beginning of the second week. Many of the ependymal cells of the laminated epithelium are produced postnatally, and the production of the specialized cells that form a parallel subependymal row extends into the third week. These cells appear to arise from the same matrix that generates earlier the neurons of the dorsomedial and ventromedial hypothalamic nuclei; their structural differentiation begins during the second week. Also the cells of the tanycytic epithelium are produced mostly postnatally, predominantly during the first week. They appear to arise from the same matrix that generated earlier the neurons of the hypophysiotropic tuberomammillary and arcuate nuclei. It is postulated that these three specialized ventricular linings are specifically related to the three cpmponents of the endocrine hypothalamus with which they have shared neuroepithelial sites of origin.

Animals↗
PubMed1987

Ultrastructure of apical specializations of taste cells in the mudpuppy, Necturus maculosus.

The first interaction of taste stimuli with lingual chemoreceptors occurs on the apical membrane of taste cells, since only that portion is exposed to the oral cavity. To gain better insight into this interaction, we examined the pore region of taste buds in Necturus maculosus with scanning electron microscopy (SEM), transmission electron microscopy, and high-voltage electron microscopy. SEM of the pore reveals a patchwork distribution of three morphologically distinct types of apical specializations: long and branched (LB) microvilli, short and unbranched (SU) microvilli, and bundles of stereocilia. As demonstrated in thin and thick sections, LB microvilli are specializations of dark cells, SU microvilli are the apical specializations of light cells, and stereocilia arise from a cell that has the cytoplasmic markers characteristic of light cells. When left in place, the pore mucus completely covers the SU microvilli and partially covers the LB microvilli. However, stereocilia project above the surface and thus are highly exposed to taste stimuli in the oral cavity. These three morphologically distinct types of apical specializations may reveal functional differences among taste cells. The initial interaction between chemical stimulus and taste cell, and possibly chemoreceptor specificity itself, may be influenced by the morphology of the apical ending.

Animals↗
PubMed2002

Social interest and the development of cortical face specialization: what autism teaches us about face processing.

Investigations of face processing in persons with an autism spectrum disorder (ASD) inform upon theories of the development of "normal" face processing, and the story that emerges challenges some models of the nature and origin of cortical face specialization. Individuals with an ASD possess deficits in face processing and a lack of a fusiform face area (FFA). Evidence from studies of ASD can be conceptualized best using an expertise framework of face processing rather than models that postulate a face module in the fusiform gyrus. Because persons with an ASD have reduced social interest, they may fail to develop cortical face specialization. Face specialization may develop in normal individuals because they are socially motivated to regard the face, and such motivation promotes expertise for faces. The amygdala is likely the key node in the system that marks objects as emotionally salient and could be crucial to the development of cortical face specialization.

Adolescent↗
PubMed1993

Rapid freezing replica studies of membrane specializations in the proximal tubules of mouse kidney.

The membrane specializations of the fresh unfixed kidney cortex of adult and neonatal ICR mice were examined by using rapid freezing replica methods. In proximal tubular cells, numerous apical intracellular tubules exhibited helical patterns on the E face with a pitch of about 12 nm. This regular pattern was often continuous with similar striped indentations on the edge of the vacuoles connecting with the tubules. On the luminal surface (ES) of these vacuoles, membrane surface particles were arranged regularly in striped patterns with a center-to-center spacing of about 12 nm. We could not identify differentiations on the PF or PS of the same membrane systems. Another membrane specialization was a plaque or patch of clear pits in tilted lattice alignments on the P face of the large vacuoles with a center-to-center spacing of about 20 nm. This type of specialization was often observed in the neonatal mice proximal tubular cells. These membrane specializations may indicate the active membrane functions in the proximal tubules and suggest the functional continuity and structural relationship of these apical endocytic membrane systems.

Animals↗
PubMed2004

Improving the prediction of exceptionally poor tableting performance: an investigation into Hiestand's "special case".

The mechanical and flow properties of selected pharmaceutical powdered excipients and drug substances were evaluated to investigate their behavior as extremely poor tableting, or "special case," materials. The compaction stress, dynamic indentation hardness, and tensile strength of compacts compressed to 15% porosity and their powder's effective angle of internal friction were measured using the tableting indices technology and a simple shear cell, respectively. It has been previously demonstrated that compacts of special case materials exhibit a dynamic indentation hardness greater than the stress required to form the compact under slow compression conditions. In addition, new data suggest that special case materials also exhibit low compact dynamic indentation hardness, low compact tensile strength, and low powder effective angle of internal friction. These findings support the theory that the particles of such materials preferentially rearrange rather than deform under compressive conditions because bonding between them is weak. The added special case indicator measurements can be used to clearly identify exceptionally poor tableting powders during the selection of components for solid dosage formulations. Careful consideration of the data will provide guidance to the proper use of the bonding indices equations.

Excipients↗
PubMed1993

Outcomes of specialized and traditional AIDS counseling programs for impoverished women of color.

The efficacy and differential effects of specialized (S) and traditional (T) AIDS education programs on cognitive, behavioral, and psychological outcomes were investigated. The sample consisted of 858 impoverished African-American and Latina women (S = 448, T = 410). At baseline, women in the traditional group reported significantly higher distress, greater knowledge of AIDS, and less problem-focused coping. Significant improvements over the 2-week intervention interval were found for participants of both AIDS education programs for appraisal of threat, concerns, knowledge, and attitudes about AIDS, emotion-focused coping, number of sexual partners, IV and non-IV drug use, depression, and distress. However, multivariate analysis indicated that the traditional group had slightly better posttest scores on concerns, emotion-focused coping, knowledge of AIDS, and number of partners than the specialized group. The specialized group reported greater use of problem-focused coping. These differences do not detract from the substantial improvement found for both groups, but they do reinforce the conclusion that the specialized program was not more effective than its standard counterpart.

Acquired Immunodeficiency Syndrome↗
PubMed1995

Synthesis of non-translating or translating specialized ribosomes causes feedback regulation of ribosomal RNA synthesis in Escherichia coli.

Specialized ribosomes carry a mutant anti-Shine-Dalgarno region that disrupts the complementary base pairing that stabilizes the translation initiation complex with E. coli mRNAs. It has been reported that production of specialized ribosomes does not cause the inhibition of chromosomal rRNA synthesis that follows production of wild-type ribosomes. We proposed that enabling translation on specialized ribosomes by providing mRNA with a complementary mutation in the Shine-Dalgarno region would restore feedback regulation and inhibit chromosomal rRNA synthesis. With both our system and the system studied previously, we saw feedback regulation regardless of whether the specialized ribosomes were translating. As reported previously, transcription from plasmid-borne promoters decreased as chromosomal rRNA synthesis was repressed, suggesting that the lambda PL and tac promoters may be sensitive to the effector(s) of feedback regulation.

Base Sequence↗
PubMed1999

Individual differences in the hemispheric specialization of dual route variables.

The dual route model suggests that reading of letter strings can occur through both a lexical and a nonlexical route. Hemispheric specialization of these routes has also been posited, suggesting that the left hemisphere has both lexical and nonlexical routes while the right hemisphere has only a lexical route. However, some recent data conflict with this hemispheric dual route model, suggesting that both hemispheres may have access to both routes. The purpose of the present study was to investigate individual differences in the hemispheric specialization of these routes and to determine whether these group differences in their specialization might explain conflicts in the literature. The effect of four individual difference factors was explored: handedness, biological sex, menstrual stage (i.e., fluctuations in estrogen), and self-rated degree of masculinity (i.e., sexual attribution). We looked at the interaction of these individual differences with the following dual route variables: (i) string length, (ii) word frequency, (iii) regularity of grapheme-phoneme correspondences of words, and (iv) the interaction of frequency and regularity using a bilateral lexical decision task. We observed that sex, menstrual stage, and masculinity each affected hemispheric specialization of the dual route variables, but did so in different ways. We posit that both hemispheres have orthographical (lexical) access as well as phonological (nonlexical) access to words. Further, we suggest that the presence of phonological processing in the right hemisphere depends on available resources and the strategies used, which are subject to individual differences.

Adult↗
PubMed1978

Glial membrane specializations in extraparanodal regions.

Previous freeze-fracture studies of central myelinated nerve fibres have demonstrated a distinctive junction in the paranodal region formed between the terminal loops of the glial cell and the axolemma. This unique junction is characterized by the presence of diagonally oriented rows of particles in the P face and to a lesser extent in the E face of the glial cell and an equivalent pattern in the axolemma. In both, the rows are spaced at 250--300 A intervals. Although this junction was originally thought to be peculiar to the paranodal region, examples of the same pattern have now been seen in extraparanodal regions in the central nervous system where they appear as circumscribed patches of membrane exhibiting a pattern identical to that in the paranodal glial loops. All examples found were in the immediate vicinity of myelinated nerve fibres and in one case the membrane containing the specialized patch was identified as a lamella of a myelin sheath. These observations constitute evidence that this distinctive membrane specialization is not limited to the paranodal axoglial junction but can also be found in glial membrane specialization is not limited to the paranodal axoglial junction but can also be found in glial membranes not in immediate contact with the specialized membrane of the paranodal axolemma.

Animals↗
PubMed2006

Attitude and knowledge of high school pupils towards adolescents with special needs (Tourette's syndrome).

OBJECTIVE: To determine high school pupils' attitudes towards adolescents with special needs (for example: TS); to learn what they know about the symptomatology and the exceptional behavior of TS; and what they think about their social future. METHODS: Ninety-nine pupils participated in the study. Their mean age was 16.7 +/- 0.8 years. Forty-eight point five percent were boys, and the rest girls. They completed a questionnaire concerning knowledge and attitudes towards adolescents with special needs (diagnosed as TS). They had participated in lessons and class talks about handicapped children with psycho- behavioral symptoms. RESULTS: The scores for their knowledge were at a level of 68.9%. Half of the pupils knew and responded correctly that TS was of genetic origin; but the most important: they expressed a comprehensive and tolerant attitude towards impaired behavior in TS at a level of 55.3%. The tolerant attitude increased with advancing age and with school grades. The attitudes were more comprehensive in families suffering form their own emotional or other psychiatric difficulties. Forty-three point four percent of pupils understand and consider TS to be an emotional, behavioral and psychiatric entity. Sixty-two point six percent of pupils understand as well and believe that the disruptive behavior and outbursts in TS are involuntary and not under the adolescent's control. On the other hand, a quarter of the pupils see justification for repeated punishment of TS adolescents for their impaired behavior. Fifty-six point six percent of regular pupils were ready to develop friendship with TS classmates in spite of their unexpected and unruly behaviour. Eight-three point eight percent of pupils believe it is better to inform teachers and classmates about the impaired behavior of these TS adolescents. Concerning the future of these disabled adolescents, pupils scored a level of 44% for their optimistic beliefs about success in future life; 52% believe that in spite of all difficulties TS adolescents would be able to live an ordinary life, to raise a family and to work. CONCLUSIONS: It is crucial to improve pupils' attitudes in schools (as well as their teachers') towards adolescents with special needs (including TS). The authors recommend that TS be considered as a neuro-behavioral and psychiatric disorder; it should be considered as a disability, which calls for comprehension, (not punishment). It would also be of value to speak in classes about the handicaps and neurobehavioral limitations for example of these TS adolescents, as well as about other pupils in school with special needs, in order to behave socially correctly towards them. The final aim will be that pupils in school will learn to accept the different child and adolescent as they are.

Adolescent↗
PubMedDate not supplied

Role of percutaneous transhepatic obliteration for special types of varices with portal hypertension.

The treatment of special types of varices with portal hypertension has not yet been established. We were able to control 13 cases of special types of varices by percutaneous transhepatic obliteration (PTO). These 13 cases consisted of 2 esophagojejunal varices after total gastrectomy for gastric cancer, 1 stoma varices after abdominoperineal excision for rectal cancer, 2 mesenteric varices with encephalopathy, 1 gastric variceal rupture, 1 gastrorenal and gastroazygos shunt with encephalopathy, 3 giant bar-type esophageal varices, 2 isolated gastric varices with gastropericardiac shunts, and 1 isolated gastric varices with gastrophrenic shunt. The special types of varices were successfully embolized in all cases and there were no complications. We conclude that the PTO is still an effective and safe treatment for special types of varices with portal hypertension.

Aged↗
PubMed2006

Need for an individualized and aggressive management of multinodular goiters of endemic zones by specially trained surgeons: experience in western Nepal.

BACKGROUND: The goals of the present study were to explore the presentation of multinodular goiter (MNG) and solitary thyroid nodules (STN) in the sub-Himalayan belt, including the risk of malignancy, and to evaluate whether specialized surgeon training in endocrine surgery has an effect on reducing complications. METHODS: This retrospective study (1998-2003) analyzed 624 patients with thyroid disorders seen in the thyroid clinic of a tertiary care hospital in western Nepal. The findings included 67.7% (n = 423: euthyroid, 297, toxic, 126) multinodular goiters (MNG) and 18.5% (n = 116) STN. Rest of patients of other thyroid disorders were excluded from the study. Ultrasonography and fine-needle aspiration cytology (FNAC) were the available diagnostic adjuncts. To evaluate the role of surgeon training, outcomes were compared between patients cared for by surgeons specially trained in endocrine surgery and those who were not. Prognostic markers indicated aggressiveness of cancers. RESULTS: Of the 539 MNG and STN patients in this series, 236 underwent operation. Of these, 25.7% (139/539) were toxic, and 11.31% had associated carcinoma. Aggressive cancers, like poorly differentiated (4.9%) and anaplastic types (18%), were more common than in series of patients from iodine-sufficient regions. Patients 40-55 years of age were more likely to have toxicity, and those > 60 years of age were more likely to have aggressive cancers. Postoperative complication rates were lower in the group treated by surgeons who had special training in endocrine surgery. CONCLUSIONS: There is a higher incidence of toxicity and malignancy in MNG in an endemic goiter zone. The limited diagnostic and therapeutic facilities in the region under study warrant a high degree of clinical suspicion and judgment, sound knowledge of thyroid physiology, thorough interpretation of hormone test results, and meticulous surgical techniques. The treatment must be individualized with consideration of humanitarian and socioeconomic factors, without compromising the quality of care and its long-term consequences. Aggressive management of malignancy and toxicity with total thyroidectomy is needed as primary therapy in many instances. However, subtotal excision is more useful in carefully selected cases with a small remnant. Specialized training in thyroid surgery appears to be valuable in reducing complications.

Adolescent↗
PubMed2006

Risk factors and musculoskeletal complaints in non-specialized nurses, IC nurses, operation room nurses, and X-ray technologists.

OBJECTIVES: To gain more insight into the prevalence rates of musculoskeletal complaints of neck-shoulder and low back and to determine the relation between physical and psychosocial work-related risk factors and the complaints mentioned in non-specialized nurses, operation room nurses, Intensive Care (IC) nurses and X-ray technologists. METHODS: The study population consists of 3,169 employees affiliated to eight university hospitals in the Netherlands. The study was conducted using a cross-sectional survey design. The parameters under study were having or having had (severe) low back or neck-shoulder complaints during the past year. In logistic regression analyses odds ratio's and CI 95% were estimated for all relevant risk factors for each of the four professional groups. RESULTS: In all groups prevalence rates of musculoskeletal complaints were high: low back 76%, neck-shoulder 60%. Operation room nurses perceived more neck-shoulder complaints (12 months prevalence) than non-specialized nurses and IC nurses perceived less severe low back complaints than non-specialized nurses. Four physical risk factors and one psychosocial factor were associated with low back complaints in all groups. CONCLUSIONS: The results of the present study indicate that both low back complaints and neck-shoulder complaints are major health problems in the four professional groups under study. The prevalence rate of neck-shoulder complaints in operation room nurses is higher than in non-specialized nurses and IC nurses, the latter groups having high prevalence rates already. The exposure to risk factors is perceived differently by each of the professional groups. The professional groups under study all are target for preventive interventions; these interventions need to be specified for each of the professional groups.

Adult↗
PubMed1997

Specialization in multi-agent systems through learning.

Specialization is a common feature in animal societies that leads to an improvement in the fitness of the team members and to an increase in the resources obtained by the team. In this paper we propose a simple reinforcement learning approach to specialization in an artificial multi-agent system. The system is composed of homogeneous and non-communicating agents. Because there is no communication, the number of agents in the team can easily scale up. Agents have the same initial functionalities, but they learn to specialize and so cooperate to achieve a complex gathering task efficiently. Simulation experiments show how the multi-agent system specializes appropriately so as to reach optimal (or near-to-optimal) performance in unknown and changing environments.

Animal Communication↗