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1.
The cold-shock response — a hot topic 总被引:4,自引:2,他引:2
2.
Gender differences in anaerobic power tests 总被引:1,自引:0,他引:1
J. L. Mayhew Pamela C. Salm 《European journal of applied physiology and occupational physiology》1990,60(2):133-138
The purpose of this study was to determine if the differences in anaerobic power between males and females could be accounted for by differences in body composition, strength, and neuromuscular function. A total of 82 untrained men and 99 women took part in the study. Body composition, somatotype, isometric strength, neuromuscular function were measured, and four anaerobic power tests performed. The men were significantly different from the women on all strength, power, and neuromuscular measurements except reaction time and on all anthropometric and somatotype dimensions except ectomorphy. Strength and anthropometric dimensions were similarly related to anaerobic power values within each sex. Relative fat (%fat) exerted different degrees of influence on sprint and jump performances in each sex. Removing the influence of anthropometric, strength, and neuromuscular differences by analysis of covariance reduced, but did not remove, the significant differences between the sexes. Therefore, factors other than lean body mass, leg strength, and neuromuscular function may be operating in short-term, explosive power performances to account for the differences between the sexes. The task-specific nature of anaerobic power tests and the relatively large influence of anthropometric factors on power production were confirmed. 相似文献
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4.
D. S. P. Patterson D. Sweasey Pamela J. Brush J. D. J. Harding 《Journal of neurochemistry》1973,21(2):397-406
Congenital tremor, type A-IV is an inherited abnormality of British Saddleback piglets characterized by the presence of poorly myelinated axons throughout the CNS. This is reflected by a general lowering of the spinal cord lipid content to about half control values. In particular, cerebroside and plasmalogen levels are markedly reduced. Changes in the fatty acid composition of total lipid extracts and two isolated cerebroside fractions suggest that there is a metabolic defect in which fatty acid chain elongation, desaturation and hydroxylation are sub-optimal. Cholesterol esters accumulate, make up about 30 per cent of total sterols and contain more than 90 per cent of C16 and C18 fatty acids. These may have arisen through the breakdown of cerebrosides containing abnormal proportions of these acids. Slightly increased levels of acid hydrolase activity appear to confirm that abnormal or immature myelin is disposed of by enhanced macrophagic activity. Differences between this and type A-III, the sex-linked inherited form of cerebrospinal hypomyelinogenesis are discussed and comparisons made with two forms of murine leuko-dystrophy. 相似文献
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Rachael E. van Pelt Catherine M. Jankowski Wendolyn S. Gozansky Pamela Wolfe Robert S. Schwartz Wendy M. Kohrt 《Obesity (Silver Spring, Md.)》2011,19(2):422-428
We have previously shown a favorable association of subcutaneous leg fat with markers of insulin resistance and dyslipidemia in postmenopausal women. It is not known whether there is a sex dimorphism in the association of lower‐body adiposity with reduced metabolic risk. Thus, our primary aim was to determine whether the favorable association of thigh subcutaneous fat, independent of abdominal fat, is also observed in older men. Mid‐thigh and abdominal fat areas were measured by computed tomography (CT) in 108 older men and postmenopausal women (mean ± s.d.; 69 ± 7 years). Additionally, trunk and leg fat mass (FM) were measured by dual‐energy X‐ray absorptiometry (DXA). Markers of insulin resistance and dyslipidemia were determined from oral glucose tolerance tests and lipid and lipoprotein measurements, respectively. Outcomes were fasted and postchallenge (area under the curve, AUC) insulin (INSAUC) and glucose (GLUAUC), product of the insulin and glucose AUC (INSAUC × GLUAUC), triglycerides (TG), and high‐density lipoprotein (HDL)‐cholesterol. Consistent with our previous findings in postmenopausal women, adjusting for DXA trunk FM revealed a favorable association of DXA leg FM with the metabolic risk outcomes in both older men and postmenopausal women. Likewise, adjusting for CT abdominal visceral fat generally revealed a favorable association of CT thigh fat with metabolic risk outcomes in women, but not men. The discordance between the DXA and CT results in men is unclear but may be due to sex differences in visceral fat accrual. The mechanisms underlying the protective effect of thigh fat on metabolic risk factors need to be elucidated. 相似文献
7.
Upon irradiation in the ultraviolet region aromatic chromophores may transfer energy to a nearby Tb3+, which in turn emits a green phosphorescence. This paper reports the characterization of the ultraviolet excitation spectra of aromatic chromophores capable of transferring energy to Tb3+ by monitoring of the green Tb3+ emission in the 540-550 nm region. Results are included for complexes containing phenyl, hydroxyphenyl, indole. and catechol chromophores. Characteristic excitation spectra are presented for the aromatic chromophores occurring as side chains in proteins. Though it is preferable to compare entire excitation spectra, the ratio of intensities at 292 to 276 nm, R, is suggested as a useful diagnostic criterion. Numerical R values are indicative of the following aromatic side chains as the energy donor to Tb3+: R <0.2, unionized tyrosine; R = 0.5 to 1.0, tryptophan; and R > 1.8. ionized tyrosine. Tlie phenylalanyl chromophore displays a definitive excitation spectrum at shorter wavelengths. For ovotransferrin R = 0.9 and comparison of the full excitation spectra suggests that it contains comparable contributions from both ionized tyrosine and tryptophan side chains. Some difficulties in obtaining reliable excitation spectra are described. An analysis of inner-filtering of incident light reveals that for an absorbance less than 0.8 the excitation spectrum is broadened and flattened compared to the absorption spectrum. At maximum absorbances greater than 0.8 false maxima may appear to both sides of a real maximum. Two spurious maxima in an excitation spectrum were generated in a Tb3+ complex and compared to the correct excitation spectrum of the same complex obtained at lower absorbance. 相似文献
8.
Pamela J. Woods 《Environmental Biology of Fishes》2010,88(2):153-168
Correlations of feeding morphology with body morphology reflect ecological variation of a species and the geographic or ontogenetic
scales over which it occurs. In this study, evidence was found for geographic variation in lower pharyngeal jaw (LPJ) morphology
of Cymatogaster aggregata Gibbons (Embiotocidae, Teleostei) in the Pacific Northwest, U.S.A. Correlations of LPJ morphology with body morphology were
more obvious in adulthood than the juvenile stage. Morphological patterns corresponded better with environmental variables
and gut contents than geographic proximity, indicating that they were most likely caused by habitat differences. Qualitative
common garden experiments indicated the nature and direction of plastic responses, and indicate a likely plastic origin to
most naturally observed differences. Recognizing ecological patterns via morphology is an important first step in understanding
how and when ecological mechanisms influence the functional role of an organism within its environment. 相似文献
9.
Regeneration of Triticum aestivum apical explants after microinjection of germ line progenitor cells with DNA 总被引:2,自引:0,他引:2
A highly efficient method of regenerating fertile, phenotypically normal plants from shoot apex cultures of T. aestivum was developed. The hypodermal layer (L2) of the vegetative apex containing germ line precursor cells could be located with bright field microscopy and targeted for microinjection. Fluorescently labelled dextrans were used as markers to develop a microinjection procedure which did not disrupt nuclear or cytoplasmic structure. This procedure was used to inject plasmid DNA into L2 cells. Capillary microinjection did not shear the plasmid DNA and delivery of DNA was confirmed by polymerase chain reaction analysis of DNA isolated from injected apices. The significance of these findings in relation to the development of cereal transformation systems will be discussed. 相似文献
10.
Bibiana S. O. Fam Guillermo Reales Pedro Vargas‐Pinilla Pamela Par Lucas H. Viscardi Vinicius A. Sortica Aline B. Felkl lvaro de O. Franco Aldo B. Lucion Claudio M. Costa‐Neto Alcides Pissinatti Francisco M. Salzano Vanessa R. Paixo‐Crtes Maria Ctira Bortolini 《American journal of primatology》2019,81(8)
Platyrrhini (New World monkeys, NWm) are a group of primates characterized by behavioral and reproductive traits that are otherwise uncommon among primates, including social monogamy, direct paternal care, and twin births. As a consequence, the study of Platyrrhine primates is an invaluable tool for the discovery of the genetic repertoire underlying these taxon‐specific traits. Recently, high conservation of vasopressin (AVP) sequence, in contrast with high variability of oxytocin (OXT), has been described in NWm. AVP and OXT functions are possible due to interaction with their receptors: AVPR1a, AVPR1b, AVPR2, and OXTR; and the variability in this system is associated with the traits mentioned above. Understanding the variability in the receptors is thus fundamental to understand the function and evolution of the system as a whole. Here we describe the variability of AVPR1b coding region in 20 NWm species, which is well‐known to influence behavioral traits such as aggression, anxiety, and stress control in placental mammals. Our results indicate that 4% of AVPR1b sites may be under positive selection and a significant number of sites under relaxed selective constraint. Considering the known role of AVPR1b, we suggest that some of the changes described here for the Platyrrhini may be a part of the genetic repertoire connected with the complex network of neuroendocrine mechanisms of AVP–OXT system in the modulation of the HPA axis. Thus, these changes may have promoted the emergence of social behaviors such as direct paternal care in socially monogamous species that are also characterized by small body size and twin births. 相似文献