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1.
G Gavellas M R Disbrow K H Hwang D K Hinkle J J Bourgoignie 《Laboratory animal science》1987,37(5):657-662
Minimally invasive techniques were used to collect urine with an external catheter together with automated intermittent monitoring of arterial blood pressure in awake male baboons. Using endogenous creatinine, 24-hour creatinine clearances were measured for 2 to 3 consecutive days in four intact and in four uninephrectomized baboons. Despite large differences in urinary volume and sodium excretion, reproducibility of 24-hour creatinine clearances was within 15% in 15 of 19 studies obtained from 6 of 8 animals. Arterial blood pressure was monitored intermittently at 30 to 60 minute intervals over 24 hours with a Dinamap monitor and recorder. Mean blood pressure averaged 71 +/- 4.4 to 89 +/- 5.5 mm Hg in different animals. Blood pressure tended to be lower at night than during the day. In separate studies using 15 to 60 minute urine collection periods, inulin clearance was compared in awake and in anesthetized animals with endogenous or exogenous creatinine clearance measured simultaneously. The clearance of creatinine systematically exceeded the clearance of inulin, even in intact animals with a normal serum creatinine. The creatinine-to-inulin clearance ratio averaged 1.16 +/- 0.03 at a serum concentration of 0.7 to 0.8 mg/dl; 1.27 +/- 0.03 at a serum creatinine of 1.0 to 1.1 mg/dl and 1.56 +/- 0.04 at a serum creatinine greater than 10 mg/dl. All values exceed unity significantly (p less than 0.001). Thus, renal function, including inulin clearance, can be measured in awake baboons. Duplicate or triplicate 24-hour urine collections are needed to assess the reliability of creatinine excretion. However, creatinine clearance overestimates glomerular filtration rate, as it does in humans. 相似文献
2.
The MgATP-stimulated accumulation of (-)-3H-nor- epinephrine (NE) by rat brain neuronal storage vesicles has been characterized in a new medium based upon polyacrylic acid (avg. MW 5,000). The medium allows careful regulation of K+ concentration (140 mM), has a large buffer capacity, and is non-permeant to membranes. Light scattering measurements have confirmed the osmotic stability of vesicles suspended in this medium. Vesicular accumulation of (-)-3 H-NE (Km 1 × 10?6 M) in this system (37°) was examined under saturating (10?5 M) and non-saturating (2 × 10?7 M) concentrations of NE. At 10?5 M NE, uptake saturated at 5 min and remained stable for periods up to one hour, with maximal uptake levels (pmol/mg protein) of 15.7±0.30 (37°), 3.0±0.49 (0°), 4.4±0.22 (reserpine pretreated ) and 6.0±0.79 (without MgATP). At 2×10?7 M NE uptake was biphasic with maximal uptake levels (pmol/mg protein) of 4.04±0.14 (37°), 0.19±0.01 (0°), 0.95±0.01 (reserpine) and 0.83±0.08 (without MgATP). Vesicle preparations refrigerated in this medium for 24 hrs displayed properties quite similar to those measured acutely (NE = 2.2x10?7 M). 相似文献
3.
IGFBP-3, a marker of cellular senescence, is overexpressed in human papillomavirus-immortalized cervical cells and enhances IGF-1-induced mitogenesis
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Human ectocervical cells, following retroviral transduction with the human papillomavirus type 16 E6/E7 oncogenes, are altered in their array of transcribed cellular genes, including increased mRNA for the insulin-like growth factor binding protein 3 (IGFBP-3). IGFBP-3 expression is associated with cellular senescence, and its addition to many cell types inhibits growth or induces apoptosis. By immunoblotting and enzyme-linked immunosorbent assay methods, we demonstrate that late-passage, immortalized E6/E7-transduced cells secrete high levels of IGFBP-3 (25 ng/ml), which represent a 500-fold increase compared to levels in early-passage, nonimmortalized transduced cells (<0.05 ng/ml). Concomitantly, these late-passage cervical cells exhibit an increase in sensitivity to IGF-1, including enhanced phosphorylation of the IGF receptor (IGF-R) and insulin receptor substrate as well as increased DNA synthesis (5-fold) and cell proliferation (3.7-fold). However, there was no change in the level of IGF-R in these cells (surface or total), and the cells did not synthesize IGF-1, indicating that these arms of the IGF pathway were independently regulated and not responsible for the augmented signaling. Consistent with a causal relationship between IGFBP-3 expression and enhanced IGF-1 responses, we found that early-passage cells could be converted to the late-passage, IGF-1-responsive phenotype by preincubation with IGFBP-3. Thus, in contrast to findings with some cell types, IGFBP-3 expression in cervical cells is associated with augmented IGF-1 signaling and cell proliferation and correlates with the timing of cellular immortalization. 相似文献
4.
Samuel N. Lockhart Steven J. Luck Joy Geng Laurel Beckett Elizabeth A. Disbrow Owen Carmichael Charles DeCarli 《PloS one》2015,10(3)
The mechanisms by which aging and other processes can affect the structure and function of brain networks are important to understanding normal age-related cognitive decline. Advancing age is known to be associated with various disease processes, including clinically asymptomatic vascular and inflammation processes that contribute to white matter structural alteration and potential injury. The effects of these processes on the function of distributed cognitive networks, however, are poorly understood. We hypothesized that the extent of magnetic resonance imaging white matter hyperintensities would be associated with visual attentional control in healthy aging, measured using a functional magnetic resonance imaging search task. We assessed cognitively healthy older adults with search tasks indexing processing speed and attentional control. Expanding upon previous research, older adults demonstrate activation across a frontal-parietal attentional control network. Further, greater white matter hyperintensity volume was associated with increased activation of a frontal network node independent of chronological age. Also consistent with previous research, greater white matter hyperintensity volume was associated with anatomically specific reductions in functional magnetic resonance imaging functional connectivity during search among attentional control regions. White matter hyperintensities may lead to subtle attentional network dysfunction, potentially through impaired frontal-parietal and frontal interhemispheric connectivity, suggesting that clinically silent white matter biomarkers of vascular and inflammatory injury can contribute to differences in search performance and brain function in aging, and likely contribute to advanced age-related impairments in cognitive control. 相似文献
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The human papillomavirus type 16 (HPV-16) E5 protein is a small, hydrophobic polypeptide that is expressed in virus-infected keratinocytes and alters receptor signaling pathways, apoptotic responses, and endosomal pH. Despite its ability to inhibit endosomal acidification, the HPV-16 E5 protein is found predominantly in the endoplasmic reticulum (ER), suggesting that its effect may be indirect and perhaps global. To determine whether E5 alters the pHs of additional intracellular compartments, we transduced human keratinocytes with a codon-optimized E5 vector and then quantified endosomal and trans-Golgi pHs using sensitive, compartment-specific, ratiometric pHluorin constructs. E5 protein increased endosomal pH from 5.9 to 6.9 but did not affect the normal trans-Golgi pH of 6.3. Confirming the lack of alteration in trans-Golgi pH, we observed no alterations in the acidification-dependent processing of the proH3 protein. C-terminal deletions of E5, which retained normal expression and localization in the ER, were defective for endosomal alkalization. Thus, E5 does not uniformly alkalinize intracellular compartments, and its C-terminal 10 amino acids appear to mediate interactions with critical ER targets that modulate proton pump function and/or localization. 相似文献
7.
Smith David Glenn Kanthaswamy Sreetharan Disbrow Michael Wagner Joseph L. 《International journal of primatology》1999,20(3):415-429
The male leaders of free-ranging harem groups of hamadryas baboons are believed to mate exclusively with the female members of their harems, which typically contain no more than 2–3 females. Using no-parent parentage exclusion analysis (PEA) we identified the paternity of 25 offspring born in a captive band of hamadryas baboons (Papio hamadryas hamadryas) containing five adult males, each with a stable harem of about five females. Nine of 13 microsatellite (SSR) loci known to be highly polymorphic in rhesus macaques (Macaca mulatta) were successful in identifying the sires of all but two offspring without knowledge of the dams' genotypes, and we were able to determine the sires of all offspring when the dams' genotypes were considered. Mating success of the males ranged between 2 and 7 offspring and bore no clear relationship to the males' ages, ranks or the number of females in their harems. The males sired 7 of the 25 offspring with females outside their own harems, with higher-ranking males exhibiting greater success monopolizing access to females in their harem than lower-ranking males did. More surprisingly, the females assigned as the dams of 14 of the 25 offspring could be unequivocally excluded from parentage. The identity of the true dam could be determined for each of these 14 offspring using single-parent PEA and was uncorrelated with the ranks of these offsprings' sires and whether the offspring were born to dams outside the sires' harem groups. The combined effect of this extraharem mating and kidnapping was that only 12 of the 25 offspring were raised within their sires' harem groups. A second group of hamadryas baboons of identical structure exhibited the same high incidences of infant kidnapping and mating outside the harem group. It is unclear whether these behaviors provide an adaptive advantage or represent aberrant behavior resulting from captivity or other circumstances. 相似文献
8.
Anthony D. Cate Timothy J. Herron E. William Yund G. Christopher Stecker Teemu Rinne Xiaojian Kang Christopher I. Petkov Elizabeth A. Disbrow David L. Woods 《PloS one》2009,4(2)
Background
Recent neuroimaging studies have revealed that putatively unimodal regions of visual cortex can be activated during auditory tasks in sighted as well as in blind subjects. However, the task determinants and functional significance of auditory occipital activations (AOAs) remains unclear.Methodology/Principal Findings
We examined AOAs in an intermodal selective attention task to distinguish whether they were stimulus-bound or recruited by higher-level cognitive operations associated with auditory attention. Cortical surface mapping showed that auditory occipital activations were localized to retinotopic visual cortex subserving the far peripheral visual field. AOAs depended strictly on the sustained engagement of auditory attention and were enhanced in more difficult listening conditions. In contrast, unattended sounds produced no AOAs regardless of their intensity, spatial location, or frequency.Conclusions/Significance
Auditory attention, but not passive exposure to sounds, routinely activated peripheral regions of visual cortex when subjects attended to sound sources outside the visual field. Functional connections between auditory cortex and visual cortex subserving the peripheral visual field appear to underlie the generation of AOAs, which may reflect the priming of visual regions to process soon-to-appear objects associated with unseen sound sources. 相似文献9.
10.
The ATP-stimulated accumulation of L-[3H]glutamate by whole brain synaptic vesicle preparations from long-sleep and short-sleep mice, lines selectively bred for difference in sleep time response to acute ethanol administration, was examined. L-[3H]Glutamate accumulation in vesicles from short-sleep mice was approximately twice that observed in vesicles from long-sleep mice at three glutamate loading concentrations. The vesicular content of endogenous L-glutamate in crude and enriched vesicle preparations from short-sleep mice was approximately 1.5-fold higher than in vesicles from long-sleep mice. The data suggest that L-glutamate associated with synaptic vesicles may serve a role in glutamate neurosecretion. 相似文献