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PubMed2003

Pancreatic endocrine and exocrine function and salivary gland function in autoimmune pancreatitis before and after steroid therapy.

INTRODUCTION: Autoimmune pancreatitis (AIP) is a distinct clinical entity in which an autoimmune mechanism may be involved in pathogenesis. AIM: To investigate salivary gland function in addition to pancreatic endocrine and exocrine function in patients with AIP, and to determine changes occurring after steroid therapy. METHODOLOGY: Fasting serum glucose levels, oral glucose tolerance tests or glycosylated hemoglobin values were examined in 19 patients with AIP. N-benzoyl-L-tyrosyl-p-aminobenzoic acid excretion test, sialochemistry and parotid gland scintigraphy were performed in 8 patients. RESULTS: Eight patients had evidence of DM. Steroid therapy subsequently improved insulin secretion and glycemic control in 3 of 5 patients treated. Pancreatic exocrine function was reduced in 88% of patients. Impaired pancreatic exocrine function improved after steroid therapy in 3 of 6 patients treated. The 3 patients also showed treatment-related improvement in endocrine function. Concentration of beta2-microglobulin in saliva was significantly raised in patients with AIP compared with controls (P < 0.05). Ratio of cumulative peak count to injected radionuclide and washout ratio in parotid scintigraphy in patients with AIP was significantly lower than those of controls (P < 0.01). Salivary gland dysfunction improved after steroid therapy in all 5 patients treated. CONCLUSIONS: Pancreatic endocrine and exocrine and salivary gland function were frequently impaired in patients with AIP, and steroid therapy was occasionally effective for these dysfunctions.

Adult↗

PubMed2004

Alleviated tension at the repair site enhances functional regeneration: the effect of full range of motion mobilization on the regeneration of peripheral nerves--histologic, electrophysiologic, and functional results in a rat model.

BACKGROUND: In the clinical management of combined tendon and nerve injuries, competing treatment strategies are well known. The effect of mobilization on the functional regeneration of peripheral nerves remains controversial. This study sought to determine the effect of full range of motion mobilization on nerve repair by using tubular segmental nerve splinting to block movement, and thereby variable tension, at the nerve repair site. METHODS: In 96 rats, the right sciatic nerve was transected midthigh and coapted immediately microsurgically. The groups used in the study were as follows: group N, epineural nerve repair; group T, segmental tubular nerve splinting with fixed in situ tension at the nerve suture site,allowing segmental movement only; group TN, segmental tubular nerve splinting with alleviated in situ tension at the nerve suture site, allowing segmental movement only; and group TM, segmental tubular nerve splinting without fixed in situ tension at the nerve suture site, allowing movement of the nerve suture site. Full range of motion of the lower limbs was ensured by passive motion of hind limbs once a week after functional testing. Blinded histologic, immunohistochemical, and electrophysiologic assessment and 12 postoperative weekly function tests were carried out. RESULTS: Functional and electrophysiologic results were significantly better in group TN, by segmental tubular nerve splinting with alleviated in situ tension at the nerve repair site, mainly because of less scar formation and enhanced endoneural angiogenesis at the nerve suture segment. CONCLUSION: Full range of motion mobilization may impede functional nerve recovery by significant endoneural collagenization and decreased angiogenesis at the nerve suture segment. Complete alleviation of in situ (pathophysiologic) tension at the nerve suture site seems to improve functional peripheral nerve regeneration.

Animals↗

PubMed2003

nth-Nearest-neighbor distribution functions of an interacting fluid from the pair correlation function: a hierarchical approach.

The paper presents a general formalism for the nth-nearest-neighbor distribution (NND) of identical interacting particles in a fluid confined in a nu-dimensional space. The nth-NND functions, W(n,r) (for n=1,2,3, em leader) in a fluid are obtained hierarchically in terms of the pair correlation function and W(n-1,r) alone. The radial distribution function (RDF) profiles obtained from the molecular dynamics (MD) simulation of Lennard-Jones (LJ) fluid is used to illustrate the results. It is demonstrated that the collective structural information contained in the maxima and minima of the RDF profiles being resolved in terms of individual NND functions may provide more insights about the microscopic neighborhood structure around a reference particle in a fluid. Representative comparison between the results obtained from the formalism and the MD simulation data shows good agreement. Apart from the quantities such as nth-NND functions and nth-nearest-neighbor distances, the average neighbor population number is defined. These quantities are evaluated for the LJ model system and interesting density dependence of the microscopic neighborhood shell structures are discussed in terms of them. The relevance of the NND functions in various phenomena is also pointed out.

Journal Article↗

PubMed1993

The asymmetric regions of rotation functions between Patterson functions of arbitrarily high symmetry.

Rotation functions between Patterson functions can be calculated and analyzed more efficiently when it is possible to consider only a unique or asymmetric region of rotation space. Previous authors have succeeded in characterizing the symmetries and asymmetric units of rotation functions between Patterson functions whose symmetries are less than cubic. Here we describe a simple and general solution that applies to rotation functions between Patterson functions of any symmetry, including cubic. The method relies on partitioning rotation space into Dirichlet domains.

Chemistry, Physical↗

PubMed1997

The functional organization of working memory processes within human lateral frontal cortex: the contribution of functional neuroimaging.

Recent functional neuroimaging studies have provided a wealth of new information about the likely organization of working memory processes within the human lateral frontal cortex. This article seeks to evaluate the results of these studies in the context of two contrasting theoretical models of lateral frontal-lobe function, developed through lesion and electrophysiological recording work in non-human primates (Goldman-Rakic, 1994, 1995; Petrides, 1994, 1995). Both models focus on a broadly similar distinction between anatomically and cytoarchitectonically distinct dorsolateral and ventrolateral frontal cortical areas, but differ in the precise functions ascribed to those regions. Following a review of the relevant anatomical data, the origins of these two theoretical positions are considered in some detail and the main predictions arising from each are identified. Recent functional neuroimaging studies of working memory processes are then critically reviewed in order to assess the extent to which they support either, or both, sets of predictions. The results of this meta-analysis suggest that lateral regions of the frontal lobe are not functionally organized according to stimulus modality, as has been widely assumed, but that specific regions within the dorsolateral or ventrolateral frontal cortex make identical functional contributions to both spatial and non-spatial working memory.

Animals↗

PubMed1997

Preadipocyte function and aging: links between age-related changes in cell dynamics and altered fat tissue function.

OBJECTIVE: To review recent findings about changes with age in the replication and differentiation of preadipocytes, the progenitor cells in fat tissue that are capable of differentiating into fat cells, and to examine possible links between these alterations and age-related changes in fat tissue function. DESIGN: A survey and analysis of recent literature concerning changes in preadipocyte and fat cell function with age. CONCLUSIONS: Intrinsic aging changes in fat cells and preadipocytes as well as in factors extrinsic to fat tissue (such as food intake and absorption and hormonal status) contribute to age-related alterations in fat tissue function and cellularity. Changes with age in preadipocyte number, replicative potential, and capacity for differentiation, which may be linked to aging changes in fat cell size, number, and function, have been identified. The decline in preadipocyte capacity for differentiation and the associated decline in fat cell lipogenic capacity may be particularly important in contributing to the decrease in fat mass and alterations in fat tissue function that occur between middle- and old age. These declines result from blunting of the changes in gene expression that occur during preadipocyte differentiation and may, in turn, be related to altered regulation of particular transcription factors that control the preadipocyte differentiation program and maintenance of fat cell function.

Absorption↗

PubMed2001

Mutagenesis and functional reconstitution of chlamydial major outer membrane proteins: VS4 domains are not required for pore formation but modify channel function.

Chlamidial organisms are obligate intracellular pathogens containing highly antigenic porin-like major outer membrane proteins (MOMPs). MOMP epitopes are of substantial medical interest, and they cluster within four relatively short variable (VS) domains. If MOMPs adopt a beta-barrel fold, like bacterial porins, the VS domains may form extramembranous loops and the conserved regions of the protein may correspond to predicted membrane-located beta-strands. However, molecular studies on native MOMPs have been hampered by the need to culture chlamydiae in eukaryotic host cells and purification and reconstitution remain problematic. In addition, the organisms are difficult to manipulate genetically, and it has also been difficult to functionally reconstitute recombinant MOMPs. To help overcome these problems and improve our understanding of MOMP structure and function, we cloned and expressed C. trachomatis and C. psittaci MOMPs and functionally reconstituted them at the single-channel level. We measured significant functional differences between the two proteins, and by removing and exchanging VS4, we tested the hypothesis that the largest variable domain forms an extramembranous loop that contributes to these differences. Proteins in which VS4 was deleted continued to form functional ion channels, consistent with the idea that the domain forms an extramembranous protein loop and incompatible with models in which it contributes to predicted membrane-located beta-strands. Additionally, the properties of the chimeric proteins strongly suggested that the VS4 domain interacts closely with other regions of the protein to form the channel entrance or vestibule. Our approach can be used to probe structure-function relationships in chlamydial MOMPs and may have implications for the generation of effective antichlamydial vaccines.

Amino Acid Sequence↗

PubMed1995

Novel heuristics of functional neural networks: implications for future strategies in functional neurosurgery.

A hypothesis is proposed that (a) the skeletomotor basal ganglia-thalamocortical loop functions as a model of the behavior of the body and the environment, and that (b) dopaminergic neurons of the substantia nigra pars compacta comprise the substrates of an error distribution system projecting to the striatum. This error signal initiates the learning process in the basal ganglia - learning starts with increasing intensity of the error signal and is complete when the signal is minimized. Parkinson's disease (PD) may be considered as a disruption of learning processes in the basal ganglia that results from progressive degeneration of the substrate that is the error distribution system for this functional motor loop. Numerous clinical and experimental observations obtained from functional procedures for PD that show identical clinical effects in alleviating parkinsonian symptoms, e.g. thermocoagulative lesions and chronic stimulation, can be explained through the use of this conceptual theory of basal ganglia function. Because any controlling neural network must possess a model of the behavior of its controlled object, the heuristics outlined in this theory are broadly applicable for explaining the function of the nervous system, as well as being useful for planning surgical procedures and future strategies in functional neurosurgery.

Basal Ganglia↗

PubMed1992

A functional model of adult human prostate epithelium. The role of androgens and stroma in architectural organisation and the maintenance of differentiated secretory function.

A functional model of adult human prostate epithelium is described. This model shows that stromal cells, but not an androgenic stimuli, are required for architectural organisation of prostate epithelium. Within an organised structure, androgenic stimulation is required for the establishment of secretory epithelial cell morphology and associated function. In the absence of stromal cells but in the presence of androgens architectural organisation and secretory function are lost. Epithelial parenchymal units (organoids) from human prostate tissue were isolated, cultured within a three-dimensional collagen matrix, and xenografted subcutaneously into athymic mouse hosts. The grafted gels were rapidly invaded by host fibroblasts. Epithelial organisation initially disappeared but was re-established concurrently with the stromal cell invasion. In intact male hosts, cuboidal and columnar cells that expressed human prostate-specific secretory markers were found. In castrated male and in female hosts epithelial structures were lined with flattened epithelium with no secretory function. This phenomenon could be reversibly replicated by treating intact male hosts with the anti-androgen Flutamide. Gels containing organoids grafted within 0.45 microns Millipore chambers were not invaded by stromal cells and rapidly lost all epithelial organisation and secretory function. When organoids cocultured with human foreskin fibroblasts were grafted within chambers, structural organisation of the epithelium was supported. These results indicate that both heterologous human fibroblasts and mouse stromal cells are capable of permissively supporting adult human prostate epithelial function.

Aged↗

PubMed2003

Signal transduction events regulating integrin function and T cell migration: new functions and complexity.

Integrin receptors facilitate T cell function by mediating adhesive events critical for T cell trafficking and recognition of foreign antigen, including interactions with vascular endothelium, extracellular matrix components, and antigen-presenting cells. Consequently, the functional activity of integrin receptors is acutely regulated by various intracellular signals delivered by other cell surface receptors, resulting in rapid changes in T cell adhesion and migration. This review highlights recent insights into our understanding of the signaling events by which the CD3/T cell receptor complex and chemokine receptors regulate integrin function and T cell migration. These studies highlight novel functions for several signaling molecules, including the tyrosine kinases Itk and ZAP-70, and the adapter protein SLAP-130/Fyb. In addition, analysis of the regulation of integrin function and chemokine-mediated migration has highlighted the critical role that spatial localization of signaling molecules plays in signal transduction, and the importance of the actin cytoskeleton in T cell function.

Cell Adhesion↗

PubMed1980

[Changes in glucose metabolism and endocrine function in the remnant pancreas after major pancreatectomy, with special reference to the function of the anti-insulin system in Sandmeyer's diabetes (author's transl)].

Changes in glucose tolerance and the function of the anti-insulin system after a major resection of the canine pancreas were divided into three types. Immediately after the removal of 90 per cent or more of the pancreas, diabetes developed, and the function of the anti-insulin system was depressed, showing a poor response of glucagon secretion to hypoglycemia after insulin load and degeneration or destruction of the islet cells and both A and B cells, and the dosage of insulin required to control blood sugar was close to that of a total pancreatectomy. 6 to 24 weeks after the removal of 70 to 90 per cent of the pancreas, so-called Sandmeyer's diabetes occurred, in which glucose tolerance and the function of the anti-insulin system were within the normal range during the early postoperative periods, but the function of the anti-insulin system was highly activated later, showing a high response of pancreatic glucagon secretion to hypoglycemia after insulin load, accompanied by degeneration of B cells, but not A cells. These results could well explain the fact that the insulin dosage needed to control blood sugar in Sandmeyer's diabetes was 3 to 4 times more than it was in total pancreatectomy. After the removal of 70 per cent or less of the pancreas, diabetes did not occur, and glucose tolerance and the function of the anti-insulin system were maintained well, without any significant change in the islets of the remnant pancreas. Insulin therapy relieved the disturbed function of the anti-insulin system in diabetes following pancreatectomy.

Animals↗

PubMed2002

On the role of covarying functions in stimulus class formation and transfer of function.

This experiment investigated whether directly trained covarying functions are necessary for stimulus class formation and transfer of function in humans. Initial class training was designed to establish two respondent-based stimulus classes by pairing two visual stimuli with shock and two other visual stimuli with no shock. Next, two operant discrimination functions were trained to one stimulus of each putative class. The no-shock group received the same training and testing in all phases, except no stimuli were ever paired with shock. The data indicated that skin conductance response conditioning did not occur for the shock groups or for the no-shock group. Tests showed transfer of the established discriminative functions, however, only for the shock groups, indicating the formation of two stimulus classes only for those participants who received respondent class training. The results suggest that transfer of function does not depend on first covarying the stimulus class functions.

Adult↗

PubMed1991

Comparison of subjective ratings of function with observed functional ability of frail older persons.

BACKGROUND: Important clinical decisions often hinge on patients' functional status. Previous studies have shown disagreement among sources of ratings of patients' functional status. This study compared patient self-ratings, family member ratings, and physician ratings of patient function to performance-based functional testing criteria. METHODS: Five activities of daily living of 73 older patients were studied at admission to a rehabilitation unit following discharge from an acute care community hospital. Data were collected from patients, family members, and physicians and were compared with performance-based function testing. RESULTS: Patient ratings were significantly more accurate than physician ratings for walking, transferring, and telephoning. Patients were significantly more accurate than family members for rating walking and telephoning, but patients were not significantly more accurate than family members or physicians for rating eating or dressing. CONCLUSIONS: We conclude that decisions about patients' functional level should be based on performance testing. If performance testing is unavailable, patients' own ratings are most accurate, followed by family ratings. Physicians' ratings are least accurate.

Activities of Daily Living↗

PubMed1996

Functional training: muscle structure, function, and performance in older women.

Response to physical training at the cellular and whole muscle level has been established in older adults. However, the underlying molecular mechanism responsible for change has not been described nor have the relationships between change in muscle structure and functional performance been established. The purpose of this research study is to evaluate the changes of muscle ultrastructure, muscle strength, and whole body functional performance as a result of a functionally directed exercise program (stair climbing). Women (65-83 years old) selected either the control (no exercise; N = 6) or exercise (N = 7) group. The 1-year functionally based exercise program was both aerobic (75% heart rate reserve) and resistive (weighted stair climbing). Muscle ultrastructure, determined by quantitative morphometry of the vastus lateralis tissue, and maximal step-height achieved by each subject were related to isokinetic strength and muscle morphology. Changes in myofibrillar area accounted for 48% of the variance in muscle strength changes. Change in muscle contractile protein was the underlying basis for change in thigh strength which, in turn, was the basis for functional performance. These data provide evidence that, in older women, a mild functionally based training program results in improved muscle structure and performance of the lower body.

Aged↗

PubMed1993

Autonomic nervous system function in patients with functional abdominal pain. An experimental study.

Functional abdominal pain--that is, pain without demonstrable organic abnormalities--has often been associated with psychologic stress. The aim of the present study was to investigate whether sympathetic nervous system response to laboratory stress and basal parasympathetic neural activity were disturbed in 22 patients with functional abdominal pain (functional group) as compared with 14 healthy controls (healthy group) and 26 patients with organic abdominal pain (organic group) due to duodenal ulcer (DU), gallstones, or urinary tract calculi. Plasma adrenocorticotrophic hormone (ACTH) and serum cortisol measurements were included, to assess the pituitary-adrenocortical axis. Heart rate, systolic blood pressure, and plasma adrenaline increased significantly in all groups in response to a stress test (mental arithmetic). Plasma noradrenaline increased in the DU patients only, and plasma ACTH and serum cortisol did not increase at all in any of the groups. As a measure of parasympathetic neural activity, independent of sympathetic neural activity, the beat-to-beat variation of the heart rate was calculated. The functional patients had a significantly higher beat-to-beat variation expressed as the mean square successive differences of the R-R intervals (MSSD), indicating a higher basal parasympathetic neural activity (mean MSSD +/- SEM = 64 +/- 6 msec in the functional group, 46 +/- 6 msec in the healthy group, and 49 +/- 6 msec in the organic group; P = 0.03). A reduced sympathetic neural response as indicated by a lesser stress-induced increment in heart rate, was seen in both patient groups (functional, 13 +/- 2 beats/min; organic, 10 +/- 2 beats/min) as compared with the healthy group (19 +/- 2 beats/min; P = 0.003).(ABSTRACT TRUNCATED AT 250 WORDS)

Abdominal Pain↗

PubMedDate not supplied

Assessing the function of functional assessment: a consumer perspective.

The person who is most affected by the process of functional assessment is the consumer--the individual with a disability whose functional capacity is being assessed. Consumers want the functional assessment process to be conducted in a dignified manner and the results to be relevant to their needs. Many consumers, influenced by the independent living movement, focus primarily on their ability to live independently in their communities and on environmental barriers that prevent them from doing so. Yet, most functional status measures focus primarily on impairments and functional limitations, rather than on handicapping environmental factors. Consumers should be involved directly in the development and application of functional status measures so that these factors are considered appropriately. Such measures have important implications for defining programme eligibility, determining payment, assuring quality, and enhancing discharge planning.

Activities of Daily Living↗

PubMed1994

[Change with aging in eustachian tubal function--eustachian tubal function of normal ears].

Eustachian tubal function was evaluated in two age groups: children aged 4 to 14 years and adults aged 23 to 74 years. The test group of children included 224 normal ears, the test group of adults 106 normal ears. Active opening function was determined by sonotubometric eustachian tubal function testing, which measures the duration of patency of the eustachian tube during swallowing. Passive opening function was determined by tubo-tympanoaerodynamic graphy (TTAG), which measures the naso-pharyngeus pressure when tubal opening is produced by the Valsalva maneuver. 1) The duration of patency of the Eustachian tube during swallowing in children was increased from the age of 8 and was nearly equal to the adult value at the age of 11. As the children got older, the naso-pharyngeus pressure when tubal opening is produced by the Valsalva maneuver increased and was nearly the same as the adult value at the age of 10. From the above, it seems that the pressure opening type Eustachian tubal function in children changes to the muscular opening type tubal function in adults at the age of 10 or 11. 2) The duration of patency of the Eustachian tube during swallowing was shorter in the group older than 60 years. The Valsalva maneuver was higher in the group above age of 50 than in younger adults. These characteristics of the Eustachian tubes of older age groups may be among the causes of adult type serous otitis media, which often occurs in older adults.

Adolescent↗

PubMed2001

The generation of Th memory in neonates versus adults: prolonged primary Th2 effector function and impaired development of Th1 memory effector function in murine neonates.

Immunization during the neonatal period often results in Th2-biased secondary responses. To understand the regulation of this phenomenon, we have examined all phases of Th development, from the generation of primary effectors to the duration of the primary effector stage to the production of memory effector function. First, we had previously reported that although primary responses in the neonatal lymph nodes are mature, mixed Th1/Th2-like, primary responses in the spleens of the same animals are exclusively Th2-like. To determine whether Th2-dominant secondary responses are due to the Th2-polarized primary function in the spleen, neonates were splenectomized before immunization. Even in the absence of primary neonatal splenic responses, the secondary responses of neonates were Th2 dominant. Thus, the overwhelmingly Th2 primary responses in the neonatal spleen are not required to generate Th2-dominant memory in the lymph nodes. Second, we have compared the kinetics of the primary response phase in neonates and adults. In adults, Ag-specific Th2 function disappeared rapidly from both the lymph nodes and spleen. In contrast, primary Th2 function persisted out to 5 wk in both neonatal organs. Third, the generation of Th memory responses was examined in animals initially immunized as neonates and in adults. These experiments demonstrated that neonates are selectively impaired in the development of Th1 memory effector function. Together, these results indicate that neonates are biased to Th2 function at all phases of an immune response.

Adjuvants, Immunologic↗