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41.
Both M Vogel M Friedrich O von Wegner F Künsting T Fink RH Uttenweiler D 《Journal of biomedical optics》2004,9(5):882-892
We use second harmonic generation (SHG) imaging to study and quantify a strong intrinsic SHG signal in skeletal muscle fiber preparations and single isolated myofibrils. The intrinsic signal follows the striation pattern of the muscle cells and is positioned at the sarcomeric location of the myosin filaments. Interestingly, the signal is enhanced at the region where the myosin heads are located on the myosin filaments. As the intrinsic signal reflects the subcellular structure in an accurate way, SHG can be used for noninvasive high resolution structural imaging without exogenous labels in living muscle cells. This may be very important for detecting changes in myofibrillar organization occurring under pathophysiological conditions, e.g., in cardiac and skeletal myopathies. Due to the strong dependency of SHG on orientation and symmetries of the tissue, it may allow the study of dynamic interactions between the contractile proteins actin and myosin during force production and muscle shortening. Furthermore, SHG imaging can be combined with other nonlinear microscopical techniques, such as laser scanning multiphoton fluorescence microscopy, to simultaneously measure other dynamic cellular processes, representing a complementary method and extending the range of nonlinear microscopical methods. 相似文献
42.
Consecutively admitted internal medical inpatients (N=294) who were psychiatrically assessed with the Schedules for Clinical Assessment in Neuropsychiatry in a two-phase design were followed up in a review of public files on their use of medical care over 18 months. Self-rated outcome was assessed from health and fitness ratings at admission and after 1 year. ICD-10 mental disorders had a statistically significant impact on the risk (odds ratio) of high use (above the 80th percentile) of primary care, as did ICD-10 anxiety/depression, and worry about illness (as assessed by the Whiteley-7 Scale). The authors found a less-than-significant tendency for mental illness to influence the use of inpatient admissions and self-rated outcome. 相似文献
43.
44.
Basic mechanisms of the rat ERG were reinvestigated with contemporary methods of recording and photic stimulation via an optic fiber system connected with a contact lens. Flash stimulation and background illuminance were performed with photometrically defined light stimuli. ERGs recorded in darkness, from dark adapted rats, were similar with those observed in earlier work in which light flashes of much longer duration had been used. Flash stimulation carried out under stepwise increased background illuminance gave new information on the characteristics of oscillatory potentials of the ERG. In general the present observations agreed with the notion that the rods of the rat retina are as sensitive as in man, whereas the cones are functionally less efficient with respect to light sensitivity and temporal resolution. Differences in function of the cones from rat to man have to be kept in mind when using the rat ERG as a model for risk assessment in safety studies. 相似文献
45.
Diagnosis of acute myocardial infarction from sequential enzyme measurements obtained within 12 hours of admission to hospital. 下载免费PDF全文
P O Collinson E M Ramhamadany S B Rosalki J Joffe D H Evans R S Fink T W Greenwood I M Baird 《Journal of clinical pathology》1989,42(11):1126-1131
A prospective study was made of sequential changes in serum creatine kinase (CK) and CK-MB isoenzyme activity within the 12 hours following admission to the coronary care unit on 65 patients with recent chest pain. CK determinations were performed in the laboratory or in the coronary care unit using a dry reagent strip analyser. Slope values for log CK/hour and log CK-MB/hour were calculated, used to confirm or exclude the diagnosis of myocardial infarction, and compared with diagnosis by conventional means. Compared with retrospective diagnosis using all available information, the CK slope had a sensitivity of 100% and a specificity of 94%. This compared with a sensitivity of 94% and specificity of 90% for diagnosis using upper reference limits alone. Determination of CK slope permits very rapid and accurate biochemical confirmation or exclusion of myocardial infarction and the possibility of performing the measurements on the coronary care unit. It additionally offers the prospect of major cost savings resulting from early discharge or transfer from the coronary care unit. 相似文献
46.
Lung epithelial cells and extracellular matrix components induce expression of Pneumocystis carinii STE20, a gene complementing the mating and pseudohyphal growth defects of STE20 mutant yeast 下载免费PDF全文
Pneumocystis carinii causes severe pneumonia in immunocompromised hosts. The binding of P. carinii to alveolar epithelial cells and extracellular matrix constituents such as fibronectin and vitronectin is a central feature of infection, which initiates proliferation of the organism. Herein, we demonstrate that P. carinii binding to lung cells specifically alters the gene expression of the organism, regulating fungal growth. Subtractive hybridization was performed to isolate P. carinii genes expressed following binding to mammalian extracellular matrix constituents. P. carinii STE20 (PCSTE20), a gene participating in mating and pseudohyphal growth of other fungi, was identified following adherence to the extracellular matrix constituents fibronectin, vitronectin, collagen, and lung epithelial cells. The expression of PCSTE20 and a related P. carinii mitogen-activated protein kinase (MAPK) kinase gene, also implicated in signaling of mating, were both specifically upregulated by binding to matrix protein. The expression of general cyclin-dependent kinases and other MAPKs not involved in mating pathways were not altered by organism binding. PCSTE20 expression was also strongly enhanced following organism attachment to A549 lung epithelial cells. When expressed in a Saccharomyces cerevisiae ste20Delta mutant, PCSTE20 suppressed defects in both mating and pseudohyphal growth. These findings are consistent with the observed proliferation and filopodial extension of Pneumocystis organisms adherent to the epithelium in the lungs of immunocompromised hosts. PCSTE20 expression appears to represent a significant component in the regulation of the life cycle of this intractable opportunistic pathogen. 相似文献
47.
Chicken pox infection (varicella zoster virus) and acute monoarthritis: evidence against a direct viral mechanism. 下载免费PDF全文
A 9 year old boy developed acute monoarthritis of the left knee concurrent with the appearance of a varicella zoster virus (VZV) rash. Repeated VZV DNA hybridisation of the cells within the synovial fluid and synovial membrane failed to show any evidence of intracellular virus. Virus was isolated from synovial fluid 24 hours after the start of clinical infection but not later. These findings suggest that the mechanism of the arthritis is not due to viral replication inside the swollen joint. 相似文献
48.
In macaque monkeys, the posterior parietal cortex (PPC) is concerned with the integration of multimodal information for constructing a spatial representation of the external world (in relation to the macaque's body or parts thereof), and planning and executing object-centred movements. The areas within the intraparietal sulcus (IPS), in particular, serve as interfaces between the perceptive and motor systems for controlling arm and eye movements in space. We review here the latest evidence for the existence of the IPS areas AIP (anterior intraparietal area), VIP (ventral intraparietal area), MIP (medial intraparietal area), LIP (lateral intraparietal area) and CIP (caudal intraparietal area) in macaques, and discuss putative human equivalents as assessed with functional magnetic resonance imaging. The data suggest that anterior parts of the IPS comprising areas AIP and VIP are relatively well preserved across species. By contrast, posterior areas such as area LIP and CIP have been found more medially in humans, possibly reflecting differences in the evolution of the dorsal visual stream and the inferior parietal lobule. Despite interspecies differences in the precise functional anatomy of the IPS areas, the functional relevance of this sulcus for visuomotor tasks comprising target selections for arm and eye movements, object manipulation and visuospatial attention is similar in humans and macaques, as is also suggested by studies of neurological deficits (apraxia, neglect, Bálint's syndrome) resulting from lesions to this region. 相似文献
49.
R Hunter R McLuskie D Wyper J Patterson J E Christie D N Brooks J McCulloch G Fink G M Goodwin 《Psychological medicine》1989,19(4):847-855
Single photon emission tomography (SPET) with the lipophilic blood flow marker 99mTc-hexamethyl propyleneamine oxime (99mTc-HMPAO) has been used to determine regional uptake of radiolabel into brain regions of patients with presenile Alzheimer's disease and Korsakoff's psychosis, and age-matched controls. Using occipital cortical uptake as reference area, the pattern of relative regional cerebral blood flow (rCBF) was determined in other cortical areas and basal ganglia. In Alzheimer's disease, reduction in rCBF occurred most strikingly in posterior temporal and parietal areas. By contrast, in Korsakoff's psychosis, posterior temporal rCBF was maintained, although there was a trend to reduced tracer uptake in other cortical areas. These impairments of flow were correlated with impairments of neuropsychological function. In Alzheimer's disease, left posterior temporal and left parietal regions in particular showed rCBF to be strongly correlated with most aspects of cognitive function. In Korsakoff's psychosis, however, impaired flow in frontal regions was correlated with impaired performance on tests of memory and orientation. The findings in Alzheimer's disease show quantitative parallels with those from studies using Positron Emission Tomography (PET), and extend our understanding of the relationship between cognition and regional brain function in dementia. The findings in Korsakoff's psychosis offer the first direct evidence linking frontal lobe dysfunction with the cognitive impairment seen in the disorder. 相似文献
50.
Roger A. Fielding David L. Costill William J. Fink Douglas S. King John E. Kovaleski John P. Kirwan 《European journal of applied physiology》1987,56(2):225-229
Summary The purpose of this study was to examine the effects of pre-exercise glucose and fructose feedings on muscle glycogen utilization during exercise in six well-trained runners (
=68.2±3.4 ml·kg–1·min–1). On three separate occasions, the runners performed a 30 min treadmill run at 70%
. Thirty minutes prior to exercise each runner ingested 75 g of glucose (trial G), 75 g of fructose (trial F) or 150 ml of a sweetened placebo (trial C). During exercise, no differences were observed between any of the trials for oxygen uptake, heart rate or perceived exertion. Serum glucose levels were elevated as a result of the glucose feeding (P<0.05) reaching peak levels at 30 min post-feeding (7.90±0.24 mmol·l–1). With the onset of exercise, glucose levels dropped to a low of 5.89±0.85 mmol·l–1 at 15 min of exercise in trial G. Serum glucose levels in trials F and C averaged 6.21±0.31 mmol·l–1 and 5.95±0.23 mmol·l–1 respectively, and were not significantly different (P<0.05). There were also no differences in serum glucose levels between any of the trials at 15 and 30 min of exercise. Muscle glycogen utilization in the first 15 min of exercise was similar in trial C (18.8±8.3 mmol·kg–1), trial F (16.3±3.8 mmol·kg–1) and trial G (17.0±1.8 mmol·kg–1), and total glycogen use was also similar in trial C (25.6±7.9 mmol·kg–1), trial F (35.4±5.7 mmol·kg–1) and trial G (24.6±3.2 mmol·kg–1). In contrast to previous research, these results suggest that pre-exercise feedings of fructose or glucose do not affect the rate of muscle glycogen utilization during 30 min of treadmill running in trained runners. 相似文献