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31.
Background
It is a well-known phenomenon that some patients with acute left or right hemisphere stroke show a deviation of the eyes (Prévost's sign) and head to one side. Here we investigated whether both right- and left-sided brain lesions may cause this deviation. Moreover, we studied the relationship between this phenomenon and spatial neglect. In contrast to previous studies, we determined not only the discrete presence or absence of eye deviation with the naked eye through clinical inspection, but actually measured the extent of horizontal eye-in-head and head-on-trunk deviation. In further contrast, measurements were performed early after stroke onset (1.5 days on average). 相似文献32.
Laurie Wideman Leslie Consitt Jim Patrie Brenda Swearingin Richard Bloomer Paul Davis Arthur Weltman 《Journal of applied physiology》2006,101(6):1641-1647
Previous research clearly indicates a linear relationship between exercise intensity and growth hormone (GH) release and that this relationship is influenced by sex. The present study examined the GH response to increasing exercise duration in young men and women. Fifteen healthy subjects (8 men and 7 women) completed three randomly assigned exercise sessions (30, 60, and 120 min) at 70% of peak oxygen consumption. Blood samples were collected every 10 min beginning 30 min before exercise, for a total of 240 min. Total integrated GH concentration (IGHC) increased with increasing exercise duration for men and women (601, 1,394, and 2,360 microg/l.4 h; 659, 1,009 and 1,243 microg/l.4 h for 30, 60, and 120 min of exercise, respectively). Regression analysis revealed that IGHC (logarithmically transformed) was significantly influenced by exercise duration (logarithmically transformed) (120 min > 60 min > 30 min) and that a significant sex-dependent effect was present even after adjustments for fitness level and percent body fat (men > women). The slope of the regression line was greater for men than for women (1.003 vs. 0.612; P = 0.013), but the average height of the regression line was greater for women (7.287 vs. 6.595; P < 0.001). Although GH secretory pulse half-duration was greater in women (P = 0.001), and GH half-life was greater in men (P = 0.001), they were not affected by exercise duration. The total mass of GH secreted during exercise increased with exercise duration (P < 0.001) but was not affected by sex (P = 0.137). Results from the present investigation indicate that when exercise intensity is constant, exercise duration significantly increases IGHC and that this relationship is sex dependent. 相似文献
33.
Bradley RD; Adkins RM; Honeycutt RL; McDonald JH 《Molecular biology and evolution》1998,15(6):709-717
Using the strictly neutral model as a null hypothesis, we tested for
deviations from expected levels of nucleotide polymorphism at the alcohol
dehydrogenase locus (Adh-1) within and among four species of pocket gophers
(Geomys bursarius major, G. knoxjonesi, G. texensis llanensis, and G.
attwateri). The complete protein-encoding region was examined, and 10
unique alleles, representing both electromorphic and cryptic alleles, were
used to test hypotheses (e.g., the neutral model) concerning the
maintenance of genetic variation. Nineteen variable sites were identified
among the 10 alleles examined, including 9 segregating sites occurring in
synonymous positions and 10 that were nonsynonymous. Several statistical
methods, including those that test for within-species variation as well as
those that examine variation within and among species, failed to reject the
null hypothesis that variation (both within and between species of Geomys)
at the Adh locus is consistent with the neutral theory. However, there was
significant heterogeneity in the ratio of polymorphism to divergence across
the gene, with polymorphisms clustered in the first half of the coding
region and fixed differences clustered in the second half of the gene. Two
alternative hypotheses are discussed as possible explanations for this
heterogeneity: an old balanced polymorphism in the first half of the gene
or a recent selective sweep in the second half of the gene.
相似文献
34.
Adults of the human parasitic trematode Schistosoma mansoni, which causes
hepatosplenic/intestinal complications in humans, synthesize
glycoconjugates containing the Lewis x (Lex) Galbeta1-->4(Fucalpha1--
>3)GlcNAcbeta1-->R, but not sialyl Lewis x (sLex), antigen. We now
report on our analyses of Lexand sLexexpression in S.haematobium and
S.japonicum, which are two other major species of human schistosomes that
cause disease, and the possible autoimmunity to these antigens in infected
individuals. Antigen expression was evaluated by both ELISA and Western
blot analyses of detergent extracts of parasites using monoclonal
antibodies. Several high molecular weight glycoproteins in both S.
haematobium and S. japonicum contain the Lexantigen, but no sialyl
Lexantigen was detected. In addition, sera from humans and rodents infected
with S.haematobium and S.japonicum contain antibodies reactive with Lex.
These results led us to investigate whether Lexantigens are expressed in
other helminths, including the parasitic trematode Fasciola hepatica , the
parasitic nematode Dirofilaria immitis (dog heartworm), the ruminant
nematode Haemonchus contortus , and the free-living nematode Caenorhabditis
elegans . Neither Lexnor sialyl-Lexis detectable in these other helminths.
Furthermore, none of the helminths, including schistosomes, express Lea,
Leb, Ley, or the H- type 1 antigen. However, several glycoproteins from all
helminths analyzed are bound by Lotus tetragonolobus agglutinin , which
binds Fucalpha1-->3GlcNAc, and Wisteria floribunda agglutinin, which
binds GalNAcbeta1-->4GlcNAc (lacdiNAc or LDN). Thus, schistosomes may be
unique among helminths in expressing the Lexantigen, whereas many different
helminths may express alpha1,3-fucosylated glycans and the LDN motif.
相似文献
35.
Jain RK; Piskorz CF; Huang BG; Locke RD; Han HL; Koenig A; Varki A; Matta KL 《Glycobiology》1998,8(7):707-717
The selectins interact in important normal and pathological situations with
certain sialylated, fucosylated glycoconjugate ligands containing sialyl
Lewisx(Neu5Acalpha2-3Galbeta1-4(Fucalpha1-3)GlcN Ac). Much effort has gone
into the synthesis of sialylated and sulfated Lewisxanalogs as competitive
ligands for the selectins. Since the natural selectin ligands GlyCAM-1 and
PSGL-1 carry sialyl Lewisxas part of a branched Core 2 O-linked structure,
we recently synthesized Galbeta1-4(Fucalpha1-3)GlcNAcbeta1-6(SE-3Galbeta1++
+-3)GalNAc1alphaOMe and found it to be a moderately superior ligand for L
and P-selectin (Koenig et al. , Glycobiology 7, 79-93, 1997). Other studies
have shown that sulfate esters can replace sialic acid in some selectin
ligands (Yeun et al. , Biochemistry, 31, 9126-9131, 1992; Imai et al. ,
Nature, 361, 555, 1993). Based upon these observations, we hypothesized
that Neu5Acalpha2-3Galbeta1-3GalNAc might have the capability of
interacting with L- and P-selectin. To examine this hypothesis, we
synthesized Galbeta1-4(Fucalpha1-3)GlcNAcbeta1-6(Neu5Acalpha2++
+-3Galbeta1-3)- GalNAc alpha1-OB, which was found to be 2- to 3-fold better
than sialyl Lexfor P and L selectin, respectively. We also report the
synthesis of an unusual structure GalNAcbeta1-4(Fucalpha1-
3)GlcNAcbeta1-OMe (GalNAc- Lewisx-O-methyl glycoside), which also proved to
be a better inhibitor of L- and P-selectin than sialyl Lewisx-OMe.
Combining this with our knowledge of Core 2 branched structures, we have
synthesized a molecule that is 5- to 6-fold better at inhibiting L- and
P-selectin than sialyl Lewisx-OMe, By contrast to unbranched structures,
substitution of a sulfate ester group for a sialic acid residue in such a
molecule resulted in a considerable loss of inhibition ability. Thus, the
combination of a sialic acid residue on the primary (beta1-3) arm, and a
modified Lexunit on the branched (beta1-6) arm on an O-linked Core 2
structure generated a monovalent synthetic oliogosaccharide inhibitor
superior to SLexfor both L- and P-selectin.
相似文献
36.
Treva Rice Ingrid B. Borecki Claude Bouchard RD.C. Ruo 《Obesity (Silver Spring, Md.)》1993,1(4):288-294
Interest in a single gene etiology for obesity, as assessed by the body mass index (BMI), has been spurred recently by reports of a putative recessive major gene for extreme values, which accounts for as much as 40% of the variance. The major gene hypothesis was evaluated here in the Québec Family Study, a random sample of 375 French-Canadian volunteer families. This report represents one component in a more complete investigation of obesity in these families. In contrast to the recent studies, a major gene hypothesis for BMI was not verified here. Although there was a major effect, it did not conform to a Mendelian pattern of transmission. A multifactorial component (i.e., polygenic and/or common environmental factors) accounted for 42% of the phenotypic variance. In addition, evidence of heterogeneity between the generations was found. The heterogeneity was traced to the major non-Mendelian component (which accounted for 0.01% of the variance in parents and over 40% in offspring) rather than to the multifactorial one. These results would suggest that a simple recessive gene mixed model may not be sufficient to explain the familial distribution of the BMI. Several factors which may have contributed to these results include temporal trends and surrogate effects such as those related to variation in body composition and energy balance components. (OBESITY RESEARCH 1993; 1:288–294) 相似文献
37.
The performance of a passive avoidance task (measured for two trials based upon number of complete step-downs and latency to respond) and blood glucose levels were examined in five groups of animals. The groups included vasopressin-deficient (DI) and vasopressin-containing (LE) rats under ad lib (AL) and food-restricted (FR) conditions, as well as DI-FR animals provided with access to an 8% sucrose solution (SUC). In the AL condition, no significant differences were found between DI and LE animals in either step-down occurrences or blood glucose levels. However, the DI animals were significantly slower in latency to respond in trial 1. With FR, the LE animals resembled the LE-AL animals in both passive avoidance behavior and blood glucose levels. The DI-FR animals that were not provided with SUC showed an impairment in passive avoidance behavior and low blood glucose levels, whereas DI-FR animals provided with SUC showed an amelioration of passive avoidance deficiencies and had blood glucose levels comparable to AL animals and LE-FR animals. On trial 2, a significant negative correlation was found between number of step-down occurrences and blood glucose levels, and a significant positive correlation was found between latency to respond and blood glucose levels. The experiment demonstrates that: 1) because DI rats have a different responsiveness in novel situations, caution must be exercised in using response latency as a measure of passive avoidance performance in the AL condition; 2) AL and FR conditions produce different responses in DI, but not LE, animals; 3) deficiencies in passive avoidance behavior in DI-FR rats can be ameliorated by the consumption of exogenous carbohydrate; and 4) there is a significant correlation between blood glucose levels and passive avoidance behavior. 相似文献
38.
Purification and properties of a type beta transforming growth factor from bovine kidney 总被引:45,自引:0,他引:45
A B Roberts M A Anzano C A Meyers J Wideman R Blacher Y C Pan S Stein S R Lehrman J M Smith L C Lamb 《Biochemistry》1983,22(25):5692-5698
Type beta transforming growth factor (TGF-beta) has been purified 200 000-fold from bovine kidneys. This peptide is characterized by its ability to induce anchorage-dependent normal rat kidney cells to grow in soft agar in the presence of epidermal growth factor (EGF); TGF-beta is not mitogenic for cells grown in monolayer culture. Purified TGF-beta does not compete with EGF for binding to membrane receptors. The concentration of TGF-beta required to elicit a half-maximal response for formation of colonies greater than 3100 micron2 in the soft agar assay is 2-3 pM (55 pg/mL) when assayed in the presence of 0.8 nM EGF (5 ng/mL). The four-step purification procedure which includes chromatography of acid--ethanol tissue extracts on polyacrylamide sizing gels, cation exchange, and two steps of high-pressure liquid chromatography results in a 10% overall yield of colony-forming activity with a recovery of 3-4 micrograms/kg. Amino acid analysis of purified TGF-beta shows 16 half-cystine residues per mole. Analysis of the purified polypeptide by electrophoresis on sodium dodecyl sulfate-polyacrylamide gels indicates that TGF-beta is composed of two closely related polypeptide chains cross-linked by disulfide bonds. In the absence of beta-mercaptoethanol, the colony-forming activity is associated with a single silver-staining band of molecular weight 25 000; in the presence of beta-mercaptoethanol, the TGF-beta is converted to an inactive species that migrates as a single band of molecular weight 12 500-13 000. Sequence analysis indicates that at least the first 15 N-terminal amino acids of the two TGF-beta subunits are identical. 相似文献
39.
A procedure for assaying peptides at the picomole level in tissue extracts has been developed and used to measure the dipeptide carnosine in mouse olfactory bulb. In this procedure the tissue extract is reacted with 2-methoxy-2,4-diphenyl-3(2H)-furanone (MDPF), and the resultant fluorophors are resolved on a high performance reverse-phase column. Quantitation is performed in a filter fluorometer equipped with a flow cell. Carnosine was found to be present at a level of 1.93 ± 0.44 nmol/mg of tissue (mean + SD of 11 samples), in agreement with previous findings by other methods. 相似文献
40.