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PubMed1990

Dynamic electromyography. II. Normal patterns during gait.

Human gait is a complex phenomenon. Many descriptors are needed to completely describe gait in terms of the biomechanics involved. The descriptors, when expressed as a function of the gait cycle, are complex waveforms. For each of these variables, a single "normal" pattern with bands of deviation has generally been accepted as a reference in clinical/research use to explain the abnormalities in a patient's walking pattern. In fact, one observes many "normal" patterns, and a body of research has been devoted to explaining the differences between these patterns in terms of walking speed, age, cadence, sex, etc. It would be simpler in one sense to start with the fact that different people walk with different patterns, not one pattern with bands of deviation. Numerical representation of the waveforms simplifies the analysis and interpretation of waveform data and facilitates comparison between subjects or groups of subjects. When combined with pattern recognition techniques, it also is useful for identifying subpatterns within a group. In this article, the numerical representation of electromyographic data by Karhunen-Loeve expansion are combined with cluster analysis to obtain patterns of dynamic phasic activity of 10 muscles of the lower extremity. From the 35 normal subjects walking at self-selected speed, two to four patterns are developed for each of the muscles and the physiological significance of the patterns are discussed.

Electromyography↗
PubMed1993

Disulfide bonding patterns and protein topologies.

This paper examines the topological properties of protein disulfide bonding patterns. First, a description of these patterns in terms of partially directed graphs is developed. The topologically distinct disulfide bonding patterns available to a polypeptide chain containing n disulfide bonds are enumerated, and their symmetry and reducibility properties are examined. The theoretical probabilities are calculated that a randomly chosen pattern of n bonds will have any combination of symmetry and reducibility properties, given that all patterns have equal probability of being chosen. Next, the National Biomedical Research Foundation protein sequence and Brookhaven National Laboratories protein structure (PDB) databases are examined, and the occurrences of disulfide bonding patterns in them are determined. The frequencies of symmetric and/or reducible patterns are found to exceed theoretical predictions based on equiprobable pattern selection. Kauzmann's model, in which disulfide bonds form during random encounters as the chain assumes random coil conformations, finds that bonds are more likely to form with near neighbor cysteines than with remote cysteines. The observed frequencies of occurrence of disulfide patterns are found here to be virtually uncorrelated with the predictions of this alternative random bonding model. These results strongly suggest that disulfide bond pattern formation is not the result of random factors, but instead is a directed process. Finally, the PDB structure database is examined to determine the extrinsic topologies of polypeptides containing disulfide bonds. A complete survey of all structures in the database found no instances in which two loops formed by disulfide bonds within the same polypeptide chain are topologically linked. Similarly, no instances are found in which two loops present on different polypeptide chains in a structure are catenated. Further, no examples of topologically knotted loops occur. In contrast, pseudolinking has been found to be a relatively frequent event. These results show a complete avoidance of nontrivial topological entanglements that is unlikely to be the result of chance events. A hypothesis is presented to account for some of these observations.

Cysteine↗
PubMed1999

Patterns of sexual dimorphism in the hominoid distal humerus.

Basic biomechanical principles predict that body size differences and differences in the positional behavior of primates should impact on the design of the locomotor skeleton. Allometric distortions in joint shape might be expected between sexes if the degree of body size dimorphism is substantial and/or if sex-specific differences exist in behavior. Nevertheless, there are few documented cases of sexual dimorphism in the limb joints of hominoids, despite substantial body size dimorphism and some reports of intersexual differences in positional behavior. This study re-examines sexual dimorphism in the hominoid distal humerus using coordinate data, and distinguishes explicitly between degree of dimorphism (i.e., the magnitude of intersexual differences) and pattern of dimorphism (i.e. , the nature of these differences). Using a variety of multivariate morphometric methods (e.g., canonical variates analysis of Mosimann shape variables; Euclidean Distance Matrix Analysis of both form and pattern difference matrices), we address the following issues: (1) do males and females of different species and subspecies (or ethnic groups for humans) maintain similar joint shapes? (2) are multiple patterns of dimorphism evident in this region of hominoids? (3) are differences and similarities in degree and pattern predicted by phylogenetic propinquity and positional behavior? For the most part, our results support earlier findings that sexual dimorphism in the shape of the anthropoid elbow is slight. Of the eight taxa considered here, only the western lowland gorillas exhibited significant differences in the shape of the distal humerus. Gorilla gorilla gorilla also displays a significantly different pattern of dimorphism from the orang-utan. Pattern differences between Andaman Islanders and both mountain gorillas and the orang-utan also approach statistical significance (P<0.06 and P<0.08, respectively). Overall, and despite marked differences in the degree of dimorphism, the knuckle-walking African apes are more similar in patterns of dimorphism to each other than to other taxa (e.g., gorillas are more similar to orang-utans in degree, but more similar to chimpanzees and bonobos in pattern). We could find no definitive "human pattern" in our results and suspect that this is because human upper limbs face less stringent mechanical constraints since they are relieved of locomotor stresses (but we cannot rule out the possibility of undocumented differences among our human groups in sex-specific, work-related activities). We anticipate finding additional pattern differences among anthropoids in articular dimorphism as we add other taxa to our sample (including fossil hominids), and examine other joint systems.

Animals↗
PubMed2002

Taxonomic variation in the patterns of craniofacial dimorphism in primates.

Understanding sexual dimorphism in living primates is important for interpreting the biological and taxonomic significance of variation in the primate fossil record. In the past two decades, there has been an increasing emphasis on the fact that sexual dimorphism varies in both magnitude and pattern among species. Several studies have suggested that distinct patterns of dimorphism may assist in species recognition and perhaps phylogenetic analysis. This study evaluates patterns of craniofacial dimorphism in samples of 82 anthropoid primates. Dimensions of the viscerocranium tend to be more dimorphic than those of the neurocranium and orbits. Principal components analysis of phylogenetically controlled data demonstrates a basic pattern of dimorphism in overall skull proportions, and a distinction between length and breadth measurements. For any given species there can be substantial variation in the magnitude of dimorphism among dimensions, and different species can show substantially different patterns of dimorphism within and between regions of the skull and jaws. Patterns of dimorphism are clearly associated with phylogeny. Pattern similarity is not dependent on the overall magnitude of craniofacial dimorphism, or body mass dimorphism. Among all anthropoids, there are few combinations of characters that consistently show greater or lesser degrees of dimorphism. Such "stability" of patterns increases within genera. Patterns of dimorphism are likely to be useful for interpreting the taxonomic significance of variation in the fossil record. However, phylogenetic propinquity alone is not reason to use an extant species as a model for variation in an extinct species. Rather, care must be taken to identify stable patterns of dimorphism within a group of closely related extant species.

Animals↗
PubMed1994

A possible neural mechanism underlying consciousness based on the pattern processing capabilities of pyramidal neurons in the cerebral cortex.

This paper examines a possible neural mechanism underlying the phenomenon of consciousness by exploring the ability of cortical pyramidal cells to process patterns of information. A numerical model of a section of a neuron is described that enables the transient membrane potential distribution to be predicted following inputs to the cell. The neuron model incorporates learning by modelling the ability of dendritic spine receptors to undergo changes in their sensitivity if they receive inputs when their local membrane is depolarized. Simulations show the cell to be capable of recognizing patterns amongst its inputs, and to be able to extend its repertoire of learnt patterns by associating one pattern of inputs with another. These pattern processing capabilities can take place within the apical dendritic tree, whilst the soma sees a much attenuated and slower response that reflects the general level of pattern recognition taking place in the dendrites. It is argued here that the distribution of patterns stored in the apical dendrites of all the pyramidal cells represents the cortical knowledge base. Incoming patterns of information are compared with those stored in the cortical knowledge base to pick out components that have been experienced before. The resulting distribution of soma responses represents the way the incoming patterns of information are perceived. Most of the patterns learnt arise from other pyramidals and represent information about cortical behaviour itself. The distribution of soma responses therefore represents a perception of the self as well as a perception of the environment. It is argued here that this intimate perception of the self could underlie the phenomenon of consciousness.

Cerebral Cortex↗
PubMed1996

Developmental pattern of axonal pathways in the house shrew maxillary nerve.

The topographic patterns of peripheral receptors and effectors seem to contribute to the construction of the neuronal circuit in the central nervous system (CNS) in mammals. Many patterns replicating those of the periphery have been found in the CNS, and fasciculation has been regarded as having a central role in the pattern replication. The house shrew, Suncus murinus, is an excellent species in which to study this topic because it has a vibrissae system arranged in a single ordered fashion and extraordinarily well-developed trigeminal spinal tracts. Using immunostaining and retrograde-tracing techniques, we examined the developmental pattern of the maxillary nervous system in the house shrew. The results indicate that the basic pattern of axonal extension reiterates with a parallel arrangement throughout the course of development except at a site in the brainstem where the central processes bifurcate into ascending and descending branches. Dorsoventral inversion of the peripheral pattern in the spinal tract occurs with this dual-leveled bifurcation in association with the mediolaterally ordered entry of the central processes into the brainstem. The basic pattern of the central processes is established prior to the appearance of the vibrissae, indicating that the basic topographic pattern of the maxillary nerve is not related to the vibrissae system. The fasciculation pattern does not correspond to the overall layout of the arrays of vibrissae, and there are frequent exchanges of axons between fascicles both in the periphery and centrally. The parallel organization of the majority of the processes, together with the free exchange of processes between fascicles, suggests that these processes have an important role in the formation of the fasciculation and somatotopic patterns.

Age Factors↗
PubMed1979

Pattern separability in a random neural net with inhibitory connections.

Some interesting properties on pattern separation have been shown through researches by neural models of cerebellar cortex. It seems to us that those results are a part of the properties of pattern separation. A two layer random nerve net with inhibitory connections is given as a model of the cerebellar cortex. The model is composed of threshold elements there. A more general theory of pattern separation than those studied earlier is given, and the pattern separability of the model is considered. It is revealed that the standard deviation of threshold values of threshold elements has a great effect on the pattern separability and the control of the firing rate. The present study is also intended to investigate the pattern separability in such a case that the firing rate of input patterns are not equal, and a pattern includes the other pattern. It is assumed there that the standard deviation is small. Some properties of the degree of pattern separation are cleaned up.

Cerebellum↗
PubMed1993

Dietary habits and mammographic patterns in patients with breast cancer.

Between 1983 and 1986, dietary history interviews were conducted with 238 women aged 50-65 years who had surgery for stage I-II breast cancer. Diagnostic mammograms were coded in line with Wolfe's criteria in N1, P1, P2, and Dy patterns. Women with Dy pattern reported significantly higher intake of total fat, monounsaturated fatty acids (FA), polyunsaturated FA, n-3 FA, n-6 FA in per cent of energy (E%), and alpha-tocopherol in mg/10 MJ. Fat intake was lowest in women with N1 pattern and highest in those having Dy pattern. Patients having ER-rich cancers and Dy pattern reported significantly higher intake of total fat, monounsaturated FA, polyunsaturated FA, n-6 FA (E%), and alpha-tocopherol (mg/10 MJ), as well as significantly lower intake of carbohydrate (E%) and calcium (g/10 MJ). In the stepwise multivariate analysis, the multivariate-odds ratio (OR) for having P2 + Dy patterns was 1.06 (95% confidence interval (CI), 1.02-1.12) for each increment in E% of total fat. In women with ER-rich tumors this OR was 1.09 (95% CI, 1.02-1.16). The highest self-reported body mass index (BMI) was observed in women with N1 + P1 patterns. OR for having P2 + Dy patterns was 0.91 (95% CI, 0.83-0.98) for each increment in 1 kg/m2 of BMI. The results suggest that dietary habits affect the mammographic parenchymal pattern in women with breast cancer and that a high fat intake is associated with a higher proportion of mammograms with Dy pattern in such patients.

Aged↗
PubMed1996

Discrepancy between brain magnetic fields elicited by pattern and luminance stimulations in the fovea: adequate stimulus positions and a measure of discrepancy.

A conventional equivalent current dipole estimation provides one of the quantitative measures to evaluate the discrepancy between two single-dipole-like magnetic field patterns, though there is one problem; all stimulus positions in the visual field do not necessarily contribute to the generation of a single-dipole-like magnetic field. Another important problem occurs when the field pattern is complex and cannot be approximated by a dipole. This makes it difficult to evaluate the discrepancy between two magnetic field patterns by the dipole parameters. In this paper, we determined the stimulus positions adequate for generating single-dipole-like magnetic field patterns by evaluating the magnetic field's goodness-of-fit to the field generated by a single dipole. We propose to use a similarity (SIM) as a quantitative measure of the discrepancy between two complex magnetic field patterns. The SIM is defined as an angle between two magnetic field vectors. We evaluated the discrepancy between the 100 ms post-stimulus responses to pattern-reversal (Rv) stimulus, pattern-onset (Pat) stimulus, and luminance-onset (Lumi) stimulus. The following results were obtained: (1) Stimulation of some of the octants in the fovea, far from the vertical meridian, elicited a single-dipole-like magnetic field pattern at a latency of 100 ms, though stimulation of the central part of the fovea, and stimulation of the octants along the vertical meridian, did not elicit a single-dipole-like magnetic field pattern; (2) The discrepancy between responses was quantitatively evaluated by the SIM even if the field patterns were complex; (3) The SIM analysis showed that the discrepancy between the responses to the Rv and the Lumi stimuli, as well as that between the responses to the Pat and the Lumi stimuli, were greater than that between the responses to the Rv and the Pat stimuli.

Adult↗
PubMed1987

Patterns of increase in serum estradiol in response to ovarian stimulation and their relationship to oocyte fertilization and cleavage in vitro.

The in vitro fertilization and cleavage rates of oocytes obtained from patients exhibiting two different patterns of increase in serial serum concentrations of estradiol (E2) in response to ovarian stimulation were compared. Forty-two cycles (from 38 stimulated patients) were evaluated because they fulfilled requirements from two pre-defined patterns of E2 response to ovarian stimulation. In 16 cycles, serial serum E2 concentrations followed a "plateau" pattern (group A), viz., the rate of increase in the serum concentration of E2 decreased prior to the administration of human chorionic gonadotropin (hCG). In 26 cycles, serial serum E2 concentrations followed a "leap" pattern (group B), in which the rate of increase in serum concentrations of E2 increased progressively up to and including the day of hCG administration. There was no significant difference in the fertilization rate of oocytes obtained from patients exhibiting either pattern A or pattern B (78 versus 74%) but the cleavage rate was significantly higher in ova obtained from patients who exhibited pattern A rather than pattern B (72 vs 50%; P less than or equal to 0.01). In addition, embryos resulting from fertilized ova obtained from women in group A were of better quality morphologically than those obtained from women in group B (mean embryo grades, 3.9 vs 3.2; P less than or equal to 0.005). We conclude that cycles in which serial serum concentrations of E2 follow pattern A in response to stimulation give rise to oocytes that, when fertilized, yield higher cleavage rates and better-quality embryos than oocytes obtained from women in whom serial serum E2 concentrations follow pattern B.(ABSTRACT TRUNCATED AT 250 WORDS)

Chorionic Gonadotropin↗
PubMed2005

The effect of tumor invasion patterns on pathologic stage of bladder urothelial carcinomas.

The aim of this study was to investigate tumor invasion pattern, its heterogeneity and association with histopathological features and stage in invasive urothelial carcinoma of the bladder. We studied 62 cases of invasive urothelial carcinoma of the bladder. World Health Organization (WHO) 1973, WHO/ISUP 1998 and WHO 1999 systems were used for tumor grading. Pathologic staging of each case was done according to 1997 TNM system. During evaluation of the slides three main tumor invasion patterns were detected: "nodular", "trabecular" and "infiltrative". In addition, homogeneity or heterogeneity of invasion patterns was also recorded for each case. Of sixty-two invasive cases, 17 (27%) had nodular, 36 (58%) trabecular, and 9 (15%) infiltrative invasion pattern. There was a statistically significant difference between invasion patterns in relation to pathologic stage (pT) (p=0.001), but not to grade. Of the 17 cases with nodular invasion pattern and 36 tumors with trabecular invasion pattern, 13 (77%) and 26 (72%) were pT1, respectively, whereas 8 of 9 infiltrative cases (89%) were advanced stage (pT2-3). According to heterogeneity, forty-two cases (68%) had homogeneous, while the remaining 20 (32%) had heterogeneous invasion pattern. Of the 42 homogeneous cases 34 (81%) were pT1, whereas 14 of 20 heterogeneous cases (70%) were advanced stage (p=0.000). The different invasion patterns seem to have a large impact on pathologic stage, especially the infiltrative pattern. In addition, invasion heterogeneity appears to be of value in determination of biologic aggressiveness in urothelial carcinoma.

Carcinoma, Papillary↗
PubMed2001

Craniopharyngiomas: identification of different semiological patterns with MRI.

Our objectives were to analyze different semiological patterns in craniopharyngiomas studied with CT and MR sequences. Retrospective study of 26 patients with confirmed craniopharyngiomas. All cases were examined with CT and MR imaging using a variety of pulse sequences (spin echo, inversion recovery, gradient echo in-phase and opposed-phase). The analyzed component patterns were classified as solid, calcium, proteic-like, cerebrospinal fluid (CSF)-like, hematic-like, and fatty patterns. The different patterns were related by means of contingency tables and the Fisher exact test and also to epidemiological findings and tumor size. A solid pole was detected in all patients, whereas a cystic component was present in 92.3% of the cases. Calcification was visualized in 65.3%, proteic-like in 53.8%, CSF-like in 23%, hematic-like in 19.2%, and fatty component in 15.3%. There were no statistical associations between patterns, with the exception that in no case did CSF-like and proteic-like patterns coexist ( P=0.004). Tumor size was related to components. Hematic-like (17.0+/-18.9 vs 3.9+/-2.6 mm, non-present vs present) and CSF-like (16.9+/-19.6 vs 6.5+/-4.0 mm) patterns were observed most frequently in smaller tumors, whereas larger tumors usually had proteic-like (5.9+/-5.4 vs 21.1+/-21.0 mm) and calcified (4.6+/-1.9 vs 19.1+/-19.9 mm) patterns. Computed tomography and a combination of different MR images frequently allow the detection of different semiological patterns in these tumors. Semiological patterns were correlated only to tumor size.

Adolescent↗
PubMed2002

Embryonic inner ear cells reaggregate into specific patterns in vitro.

The sensory epithelia of the mammalian inner ear consist of a highly precise pattern of sensory hair cells and supporting cells. The mechanisms regulating this patterning are only beginning to be determined. The present study describes a method for culturing dissociated embryonic inner ear cells and the resulting patterning that occurs in these cultures. The results indicate that developing inner ear cells aggregate into precise patterns on a two-dimensional substrate, suggesting that intrinsic patterning mechanisms remain active in vitro. Using antibodies and scanning electron microscopy to detect hair cells and nonsensory cells, it was determined that only a subset of aggregates contained sensory hair cells. The hair cells were organized into specific patterns and surrounded by supporting cells, similar to the in vivo pattern. Additionally, hair cells increased their immunoreactivity and number of stereocilia over time, suggesting that hair cells continue to mature in vitro. Thus, the study reveals that the cells of the developing inner ear provide the necessary signals that direct sensory hair cells and supporting cells to reassociate into very precise patterns in vitro and that these patterns are reminiscent of the patterning that occurs in vivo.

Animals↗
PubMed1993

Susceptibility of small, dense, low-density lipoproteins to oxidative modification in subjects with the atherogenic lipoprotein phenotype, pattern B.

PURPOSE: To test whether low-density lipoprotein (LDL) from subjects with an atherogenic lipoprotein phenotype characterized by small, dense LDL (pattern B) demonstrates greater susceptibility to oxidative modification than LDL from subjects exhibiting primarily larger, more buoyant LDL particles (pattern A). PATIENTS AND METHODS: Measures of susceptibility to oxidative modification were compared in six density subfractions of LDL isolated from pattern A and pattern B subjects. Seven male and three female pattern A subjects and five male and two female pattern B subjects, classified on the basis of peak LDL particle size, were studied. Plasma lipid and lipoprotein levels, apolipoprotein B, mean LDL particle diameter, lag phase, and rate of oxidation after initiation of oxidation by copper sulfate were measured. RESULTS: The lag time, a measure of resistance to oxidative modification, was inversely related (p < 0.001) to LDL density in both groups of subjects, without an independent effect of phenotype. The fraction that had the major LDL peak had a shorter lag time (p < 0.05) in pattern B than in pattern A. Pattern B subjects also demonstrated an increased rate of oxidation (p < 0.005) in fraction 1, which includes remnants of triglyceride-rich lipoproteins. CONCLUSIONS: The increased atherogenic risk associated with the pattern B phenotype may result in part from increased concentrations of lipoprotein subpopulations that are relatively susceptible to oxidative modification.

Adult↗
PubMed1992

Stomatal patterning in Tradescantia: an evaluation of the cell lineage theory.

The cell lineage theory, which explains stomatal patterning in monocot leaves as a consequence of orderly divisions, was studied in Tradescantia. Data were collected to test the theory at three levels of organization: the individual stoma; stomata distributed in one dimension, in linear fashion along cell files; and stomata apportioned in two dimensions, across the length and breadth of the leaf. In an attempt to watch the patterning process through regeneration, stomata in all visible stages of development were laser ablated. The results showed that the formation of stomatal initials was highly regular, and measurements of stomatal frequency and spacing showed that pattern was determined near the basal meristem when the stomatal initials arose. Following the origin of initials, the pattern was not readjusted by division of epidermal cells. Stomatal initials were not committed when first present and a small percentage of them arrested. The arrested cells, unlike stomata, were consistently positioned in cell files midway between a developed pair of stomata. At the one-dimensional level of pattern, stomata in longitudinal files were separated by a variable number of epidermal cells and the frequency of these separations was not random. The sequential spacing of stomata also was not random, and stomata separated by single epidermal cells were grouped into more short and long series than expected by chance. The stomatal pattern across the width of the leaf resulted from cell files free of stomata which alternated with cell files containing stomata, but not with a recurring periodicity. Files lacking stomata were found only over longitudinal vascular bundles. Laser ablations of developing stomata did not disrupt the pattern in nearby cells or result in stomatal regeneration. We conclude that the cell lineage theory explains pattern as an individual stomatal initial arises from its immediate precursor and satisfactorily accounts for the minimum spacing of stomata in a cell file, i.e., stoma-epidermal cell-stoma. However, the theory does not explain the collective stomatal pattern along the cell files, at the one-dimensional level of patterning. Nor does the theory account for the for the two-dimensional distribution of stomata in which regions devoid of stomata alternate with regions enriched with stomata, but not in a highly regular nor haphazard manner. We suggest that the grouping of epidermal cells and stomata separated by single epidermal cells in cell files may result from cell lineages at a specific position in the cell cycle as they traverse the zone where stomatal initials form.(ABSTRACT TRUNCATED AT 400 WORDS)

Cell Division↗
PubMed1982

Visual attention and neuronal firing patterns in the feline pulvinar nucleus of thalamus.

In behaving cats, temporal patterns of neuronal firing were studied during slow wave sleep (SWS), motionless quiet wakefulness (QW) coupled with specific direction of the animal's attention, and during bar pressing performance (BP) for milk reward. The analysis was based on relative relations between sequential spike intervals. The strength of the method is based on the fact that the probabilities of occurrence of patterns are determined by the history of a spike train. During SWS, the neuronal firing modes closely followed the theoretical model of independent distribution of intervals, whereas during QW and BP specific for each neuron departures from the model, i.e., patterning was observed. Most importantly, in seven chronically studied neurons idiosyncratic patterns were related to direction of the animal's attention, and, very likely, to the visual forms the animals gazed at, because the patterns disappeared in the dark and during SWS without major changes in the mean firing rate. The replications of patterns upon recurrence of a particular direction of attention was proven statistically. The constancy and idiosyncrasy of these patterns were apparent even though the comparable episodes occurred several hours apart, and the animals slept and/or ate in between, and the distance, i.e., the retinal size of visual forms varied from one episode to another. On the basis of correlative evidence, it was argued that, compared to more abstract modes of information processing, the identification and quantification of patterns based on relative relations between intervals require the least amount of storage of intermediate results. Hence, these patterns are likely to represent a simple and phylogenetically old principle of communication between neurons. It was postulated that the idiosyncrasy and invariance of patterns may play a role in constancy of feature extraction and Gestalt perception.

Animals↗
PubMed2004

Differential effect of two nicotinic acid preparations on low-density lipoprotein subclass distribution in patients classified as low-density lipoprotein pattern A, B, or I.

We tested the hypothesis that treatment with nicotinic acid results in a differential blood lipid response in subjects classified as having a low-density lipoprotein (LDL) pattern A or B. One hundred eighty hypercholesterolemic subjects were randomized to placebo (n = 61), immediate-release niacin (3,000 mg/day, n = 59), or extended-release niacin (1,500 mg/day, n = 60) for 14 weeks. Lipids and lipoprotein cholesterol were determined with enzymatic methods. LDL subclass distribution was determined with 2% to 16% polyacrylamide gradient gel electrophoresis. Extended- and immediate-release niacin had significant effects on the decrease of triglycerides, total cholesterol, LDL cholesterol, apoprotein B, lipoprotein(a), and apoprotein A-I and significantly increased high-density lipoprotein cholesterol. The 2 nicotinic acid compounds and doses significantly increased mean LDL peak particle diameter and percent distribution in large LDL I and IIa, with a significant decrease in small LDL IIIa, IIIb, and IVb. In patients with LDL pattern B compared with those with pattern A, extended-release niacin (1,500 mg/day) increased LDL peak particle diameter significantly more and decreased the percent distributions of small LDL IIIa, LDL IIIb, and LDL IVa significantly more. With 3,000 mg/day, immediate-release nicotinic acid in patients with LDL pattern B exhibited a significantly greater increase in LDL peak particle diameter and large LDL IIa and IIb and significantly greater decreases in small LDL IIIa, IIIb, and IVa compared with patients with pattern A. These differences in response between patients with LDL pattern A and those with pattern B were not reflected by changes in the standard lipid profile, including apoproteins A-I and B. Nicotinic acid has a significantly different effect on lipids and lipoprotein subclass distribution in subjects classified as having LDL subclass pattern A or B. Nicotinic acid has a significantly greater effect on the decrease of small LDL subclass distribution and increase in LDL peak particle diameter in pattern B versus pattern A.

Adult↗
PubMed2004

Precision grasps of children and young and old adults: individual differences in digit contact strategy, purchase pattern, and digit posture.

The evolutionary origins and variations of the precision grip, in which an object is held between the thumb and other digits, are poorly understood. This is surprising because the neural basis of this grasp pattern, including the motor cortex and pyramidal tract have received extensive study. Most previous work has shown that features of an object to be grasped (external factors) determine grasp patterns. The objective of the present study was to investigate individual differences (central factors) in use of the pincer and other precision grips. The grasping patterns of male and female young adults, older adults and children were examined as they reached (with both left and right hand) for five small beads (3-16 mm diameter). Frame-by-frame analysis of grasping indicated a high degree of variability in digit contact strategies, purchase patterns and digit posture both within and between subjects. (1) The contact strategies consisted of five variations, depending on whether the thumb or the index finger dragged or stabilized the bead for grasping. (2) Purchase patterns consisted of seven different types of precision grips, involving the thumb and various combinations of other digits. (3) There were four variations stemming from the posture of the non-grasping digits. Grip patterns of the left and right hands were correlated in individual subjects, as were strategies used for different bead sizes. Females displayed slightly more variability in grasp patterns than did males, and digit width (obtained from photocopies of the subjects' hands) was weakly correlated with the grasp patterns used. Although it was expected that the pincer would be used for all objects, it was preferentially used for only the smallest object except for older adults who used the pincer grasp on most objects. The variability in digit contact strategies, purchase patterns, and posture of the non-grasping digits indicates that central factors (innate or learning-induced architecture of the left parietal cortex) make important contributions to the selection of a grasping pattern. These individual differences are discussed in relation to the neural control of grasping and its potential contribution to understanding the evolution, development, and pathology of the precision grip.

Adolescent↗