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1.
Successful surgical reconstruction of the upper extremities paralyzed by poliomyelitis depends largely on the careful analysis of the individual problem and replacement of critical motions of the upper extremity. These replacements or substitutions may be gained by muscle transposition, tendon transplantation, tenodesis, bone block, or arthrodesis.  相似文献   

2.
Influence of upper airway negative-pressure change on the respiratory activity of various upper airway muscles was investigated in 13 anesthetized rabbits. Phasic inspiratory activity increased or appeared during virtually all negative-pressure trials in nasolabial, cricothyroid, and posterior cricoarytenoid muscles. No phasic inspiratory activity was seen in the sternothyroid (ST) and sternohyoid (SH) muscles before negative-pressure applications but appeared during 80% of trials in ST and 62% of trials in SH. During maintained negative pressure, a gradual decline in activity was often observed in the nasolabial and laryngeal muscles, whereas a rapid decline in activity was seen in the cervical strap muscles. Reflex effects of negative pressure was markedly reduced or abolished by sectioning the internal branch of the superior laryngeal nerve bilaterally. Reflex augmentation of upper airway muscle activity reported here may have functional significance in the maintenance of upper airway patency. It could prevent upper airway collapse when negative pressure swings in the upper airway increase or facilitate recovery when large negative pressure swings are produced by obstructed inspiratory efforts.  相似文献   

3.
Repetitive occurrence of partial or total upper airway obstruction characterizes several respiratory dysfunctions such as the obstructive sleep apnea syndrome (OSAS). In OSAS patients, pharyngeal collapses are linked to a decrease in upper airway muscle activity during sleep which causes decreased upper airway wall stiffness. Continuous positive airway pressure (CPAP) is recommended as the treatment of choice. Advancements in CPAP therapy require early detection of respiratory events in real time to adapt the level of the applied pressure to airway collapsibility. The forced oscillation technique (FOT) is a noninvasive method which reflects patients' airway patency by measuring respiratory impedance. The aim of this study was to evaluate by a mathematical model of the respiratory system if FOT can provide an early detection index of total or partial upper airway obstruction. Furthermore, the simulation should suggest which characteristic features are relevant for early apnea detection in measured clinical data. The respiratory system has been treated as a series of cylindrical segments. The oropharynx analog of the model allows simulation of upper airway collapse, mimicking the situation in patients with OSAS. We calculated the input impedance for different degrees of upper airway obstruction ranging from unobstructed airways to total occlusion. Furthermore, we simulated different upper airway wall compliances. We compared the simulation with real data. The results of the study suggest that FOT is a valuable tool for assessing the degree of upper airway obstruction in patients with OSAS. Especially, the phase angle of the impedance seems to be a potentially useful tool for early apnea detection by assessing the upper airway wall collapsibility. Received: 23 July 1998 / Accepted in revised form: 26 January 1999  相似文献   

4.
Artificially produced upper airway suction inhibits the diaphragm in animals and infants; however, the effects of spontaneously generated suction in humans are unknown. We studied nine tracheostomized infants because separation of the upper from the lower airway allowed us to channel suction created by an occluded inspiratory effort to both upper and lower airways (upper + lower airway occlusions) or to the lower airway only (lower airway occlusion). The tracheostomy airway was briefly occluded at end expiration during quiet sleep. In upper + lower airway occlusions, peak airway pressure of the first occluded breath was less negative and rate of pressure decrease slower than that of lower airway occlusions, indicating that upper airway suction inhibits thoracic inspiratory muscles. The threshold for this response was less than or equal to 4 cmH2O suction pressure. The effect on inspiratory time was variable. A decrease in slope of the inspiratory pressure waveform occurring at approximately 0.12 s after inspiration onset was more marked in upper + lower airway occlusions. We conclude that infants have an upper airway reflex response to inspiratory pressure that alters not only the peak and slope but also the shape of the inspiratory pressure waveform.  相似文献   

5.
Adipose compartments of the upper eyelid: anatomy applied to blepharoplasty   总被引:3,自引:0,他引:3  
Many authors have indicated the presence of ectopic or accessory upper eyelid fat pads, but the effective rate of eyelid fat variations and the corresponding clinical features are still unclear. The purpose of this study was to evaluate the variability of upper lid fat and to define the anatomical landmarks of the adipose pockets of the upper lid. From January of 1998 to January of 2002, the authors investigated the upper eyelid fat compartments of 47 patients who underwent upper blepharoplasty. To support surgical findings, 11 fresh cadavers were also investigated; the anatomy of the intraorbital fat and of the upper eyelid fat compartments was reviewed. Ten patients (21.3 percent) showed an accessory fat pad in the upper lid, which was found on both sides in nine cases. In all patients, the third fat pad was situated lateral to the two classic compartments described by Castanares, behind the orbital septum. Surgical dissections demonstrated that this fat pad derived from the preaponeurotic fat. Anatomical dissections in three cadavers demonstrated an accessory fat compartment protruding under the inferior border of the lacrimal gland. This protruding fat derived from the preaponeurotic fat in all cases and might justify the clinical appearance of a bulge or fullness in the lateral third of the upper eyelid. In the authors' experience, the presence of an accessory upper eyelid fat pad was a frequent finding during blepharoplasty; it could be found and actually resected in about 21 percent of all cases. Surgical and experimental findings put this element as a lateral physiological extension of the preaponeurotic fat that can anteriorly protrude under the inferior border of the lacrimal gland toward the orbital septum. The clinical appearance may be a bulge or fullness in the upper eyelid, and its resection can better define the lateral one third of the supratarsal fold.  相似文献   

6.
Selective reflex activation of the genioglossus in humans   总被引:1,自引:0,他引:1  
In anesthetized or decerebrate animals, negative pressure applied to the upper airway selectively activates the hypoglossal nerve compared with the phrenic nerve. Conversely, positive pressure reduces hypoglossal nerve activity out of proportion to any change in the phrenic neurogram. We have tested the hypothesis that analogous pressure changes applied to awake humans would selectively inhibit or activate genioglossal electromyographic (EMGge) activity relative to diaphragmatic electromyographic activity (EMGdi). We studied seven normal subjects in a head-out body plethysmograph. Pressure at the mouth was either atmospheric, +10 cmH2O, or -10 cmH2O, and lung volume was held constant by applying an identical pressure to the body surface. Thus the transmural pressure distorting the respiratory system was applied only to the upper airway. Subjects breathed CO2-enriched (2-3%) room air to stimulate phasic respiratory EMGge activity. We found that -10 cmH2O pressure applied selectively to the upper airway resulted in a 49% enhancement of peak-integrated EMGge activity, but EMGdi activity remained at control levels. Positive pressure did not result in any changes in EMGge or EMGdi activity. Neither pressure resulted in significant changes in the magnitude or pattern of ventilation. We conclude that reflex mechanisms maintaining upper airway patency are demonstrable in awake humans and probably have an important role in moment-to-moment modulation of upper airway muscle activity in normal awake humans.  相似文献   

7.
K F Yee 《Biometrics》1986,42(4):961-965
Methods are given for deriving the lower and upper bounds of the probabilities for rejecting bioequivalence. Except when two formulations are nearly equal, the lower and upper bounds become very close and thus give an exact probability. The methods can be used in two- or higher-way crossover or parallel groups designs. One can also determine the sample size from the equations. The results are compared with the probabilities obtained by simulation.  相似文献   

8.
Aegilops Kotschyi Boiss. plants produce three florets per spikelet(of which the terminal floret is commonly sterile) and exhibitphysiological heterocarpy in the two caryopses which developin each spikelet. Germinability of the basal caryopsis, butnot of the upper one, was subject to environmental influencesto which the parent plant was exposed during its development.Basal caryopses produced by plants grown at low temperature,or in 16-h photoperiods, were more dormant than when producedby plants grown at higher temperature, or in 8-h photo-periods.Germinability of the upper caryopses was equally high in allcases and independent of the parental environment. The photoperiodeffects on germinability were exerted after anthesis. Matureweight of both basal and upper caryopses was higher when producedon plants grown at low temperature, or transferred from 16-hto 8-h photopenods at emergence of the flag leaf  相似文献   

9.
目的:比较由阿司匹林引发上消化道出血的相关危险因素OR值,探讨其引起消化道大出血的相关机制。方法:收集哈医大四院消化内科及心内科2009年5月份至2013年6月份仅口服阿司匹林一种非甾体抗炎药的100例患者,用药过程中引发上消化道出血的49例患者作为研究组,其余未发生消化道出血的51例患者作为对照组,采集现病史、既往史、吸烟史、行凝血常规、Hp检测及胃镜检查,经单因素统计分析筛选出阿司匹林引发上消化道出血的危险因素;通过多元Logistic回归分析得出阿司匹林引发上消化道出血的独立危险因素。结果:年龄60岁、Hp感染、既往溃疡病史、糖尿病、吸烟的患者在研究组所占比例明显高于对照组,差异具有统计学意义;经多元Logistic回归后表明年龄60岁、Hp感染、既往溃疡病史、糖尿病患者和阿司匹林引发上消化道出血的OR值具有统计学差异。结论:年龄60岁、Hp感染、溃疡病史、糖尿病患者是阿司匹林引发上消化道出血的4个独立危险因素。  相似文献   

10.
Pressure-volume behavior of the upper airway   总被引:1,自引:0,他引:1  
The study was performed to investigate the relationship between force generation and upper airway expansion during respiratory efforts by upper airway muscles. In 11 anesthetized dogs we isolated the upper airway (nasal, oral, pharyngeal, and laryngeal regions) by transecting the cervical trachea and sealing the nasal and oral openings. During spontaneous respiratory efforts the pressure within the sealed upper airway, used as an index of dilating force, decreased during inspiration. On alternate breaths the upper airway was opened to a pneumotachograph, and an increase in volume occurred, also during inspiration. Progressive hyperoxic hypercapnia produced by rebreathing increased the magnitude of change in pressure and volume. At any level of drive, peak pressure or volume occurred at the same point during inspiration. At any level of drive, volume and pressure changes increased with end-expiratory occlusion of the trachea. The force-volume relationship determined from measurements during rebreathing was compared with pressure-volume curves performed by passive inflation of the airway while the animal was apneic. The relationship during apnea was 1.06 +/- 0.55 (SD) ml/cmH2O, while the force-volume relationship from rebreathing trials was -1.09 +/- 0.45 ml/cmH2O. We conclude that there is a correspondence between force production and volume expansion in the upper airway during active respiratory efforts.  相似文献   

11.
We have examined arousal and abdominal muscle electromyogram (EMGabd) responses to upper airway pressure stimuli during physiological sleep in four dogs with permanent side-hole tracheal stomata. The dogs were trained to sleep with a tightly fitting snout mask, hermetically sealed in place, while breathing through a cuffed endotracheal tube inserted through the tracheostomy. Sleep stage was determined by behavioral and electroencephalographic criteria. EMGabd activity was measured using bipolar fine-wire electrodes inserted into the abdominal muscle layers. Static increases or decreases in upper airway pressure (+/- 6 cmH2O), when applied at the snout mask or larynx (upper trachea), caused an immediate decrease in EMGabd on the first two to three breaths; EMGabd usually returned to control levels within the 1-min test interval. In contrast, oscillatory pressure waves at 30 Hz and +/- 3 cmH2O amplitude (or -2 to -8 cmH2O amplitude) produced an immediate and sustained reduction in IMGabd in all sleep states. Inhibition of EMGabd could be maintained over many minutes when the oscillatory pressure stimulus was pulsed by using a cycle of 0.5 s on and 0.5 s off. Oscillatory upper airway pressures were also found to be powerful arousal-promoting stimuli, producing arousal in 94% of tests in drowsiness and 66% of tests in slowwave sleep. The results demonstrate the presence of breath-by-breath upper airway control of abdominal muscle activity.  相似文献   

12.
Role of upper airway in ventilatory control in awake and sleeping dogs   总被引:1,自引:0,他引:1  
We examined the role of the upper airway in the regulation of the pattern of breathing in six adult dogs during wakefulness and sleep. The dogs breathed through a fenestrated endotracheal tube inserted through a tracheostomy. The tube was modified to allow airflow to be directed either through the nose or through the tracheostomy. When airflow was diverted from nose to tracheostomy there was an abrupt increase in the rate of expiratory airflow, resulting in prolongation of the end-expiratory pause but no change in overall expiratory duration or respiratory frequency. Furthermore, electromyogram recordings from implanted diaphragmatic and laryngeal muscle electrodes did not show any changes that could be interpreted as an attempt to delay expiratory airflow or increase end-expiratory lung volume. The effects of switching from nose to tracheostomy breathing could be reversed by adding a resistance to the endotracheal tube so as to approximate upper airway resistance. The findings indicate that under normal conditions in the adult dog upper airway receptors play little role in regulation of respiratory pattern and that the upper airway exerts little influence on the maintenance of end-expiratory lung volume.  相似文献   

13.
中国大蒜芥属(十字花科)叶表皮微形态学研究   总被引:1,自引:0,他引:1  
利用光学显微镜观察了中国十字花科大蒜芥属9种1变种植物的叶表皮形态。结果表明:中国大蒜芥属植物叶上表皮细胞通常为多边形,垂周壁平直或弓形,少有稍浅波状,叶下表皮细胞为不规则形,垂周壁波状或深波状;气孔器类型均以不等细胞型为主,少有无规则型,偶有平列型。依据叶表皮特征,可将中国大蒜芥属划分为三种类型: (1)叶上表皮无气孔分布或偶见; (2)叶上表皮气孔常明显几个聚成一簇或排成短列,气孔密度小于叶下表皮; (3)叶上表皮气孔比较均匀分布,气孔密度与叶下表皮近相似。  相似文献   

14.
The effects of ethylene (C2H4), (2-chloroethyl)phosphonic acid (ethefon) and 1-aminocyclopropane-1-carboxylic acid (ACC) on senescence of isolated intact petals and of upper petal parts of carnation flowers ( Dianthus caryophyllus L. cv. White Sim) were investigated.
Isolated upper petal parts did not respond to treatment with ethefon or ACC. These tissues did, however, show severe wilting in intact petals that were treated with ethefon or ACC. When isolated upper petal parts were simultaneously treated with ACC and ethefon or ACC and ethylene, a marked synergistic effect on senescence was found. Treatment of isolated petals with radiolabeled ACC led to the accumulation of radiolabeled ACC and N-malonyl-ACC (MACC) in the upper parts. The formation of ethylene and the malonylation of ACC were inhibited by pretreatment of the flower with the inhibitor of ethylene action, silver thiosulphate (STS), which indicates that both were induced by endogenously produced ethylene. Treatment of isolated upper parts with ACC slightly increased their ethylene production. However, when these petal parts were simultaneously treated with ethylene and ACC, the conversion of ACC to ethylene was markedly stimulated.
The results indicate that, in intact petals, ethylene may be translocated from the basal to the upper part where it stimulates the activity of the ethylene-forming enzyme (EFE), thereby making the tissue receptive to ACC.
In addition, it was found that upon incubation of petal portions in radiolabeled ACC, both the petal tissue and the incubation solutions produced radiolabeled carbon dioxide. This was shown to be due to microorganisms that were able to metabolize the carbon atoms in the 2 and 3 position of ACC into carbon dioxide.  相似文献   

15.
Recent studies have shown that epidermal cholesterol synthesis is regulated by HMG CoA reductase activity and that this activity is modulated by changes in the cutaneous permeability barrier. Here, we quantitated HMG CoA reductase activity after acute and chronic barrier disruption in the upper and lower layers of murine epidermis. In unperturbed epidermis, 13 and 87% of enzyme activity localized to the upper and lower epidermis, respectively, with the majority of activity in the stratum basale. Acute barrier disruption with either acetone or sodium dodecylsulfate provoked an increase in HMG CoA reductase activity (54% and 30%) in the lower layers, but only a small change in the upper layers. However, the activation state of the enzyme was increased 50% in the upper epidermis. Correction of barrier function by occlusion with an impermeable Latex wrap prevented the increase both in enzyme activity and activation state. After chronic barrier disruption; i.e., essential fatty acid deficient (EFAD) diet, HMG CoA reductase activity was increased in the upper epidermis (161%); a change prevented by occlusion. These results show: (1) that HMG CoA reductase activity is present in both the upper and lower cell layers; (2) that acute insults to barrier integrity stimulate enzyme activity in both the upper and lower epidermis; and (3) that chronic insults provoke an increase in enzyme activity in the upper layers. These studies provide further insights into the linkage of the permeability barrier with epidermal cholesterol metabolism.  相似文献   

16.
Qifu Ma  Zed Rengel  Bill Bowden 《Plant and Soil》2007,291(1-2):301-309
Heterogeneous distribution of mineral nutrients in soil profiles is a norm in agricultural lands, but its influence on nutrient uptake and crop growth is poorly documented. In this study, we examined the effects of varying phosphorus (P) and potassium (K) distribution on plant growth and nutrient uptake by wheat (Triticum aestivum L.) grown in a layered or split soil culture in glasshouse conditions. In the layered pot system the upper soil was supplied with P and either kept watered or allowed to dry or left P-deficient but watered, whereas the lower soil was watered and fertilised with K. Greater reductions in shoot growth, root length and dry weight in the upper soil layer occurred in −P/wet than in +P/dry upper soil treatment. Shoot P concentration and total P content were reduced by P deficiency but not by upper soil drying. Genotypic responses showed that K-efficient cv. Nyabing grew better and took up more P and K than K-inefficient cv. Gutha in well-watered condition, but the differences decreased when the upper soil layer was dry. In the split-root system, shoot dry weight and shoot P and K contents were similar when P and K were applied together in one compartment or separated into two compartments. In comparison, root growth was stimulated and plants took up more P and K in the treatment with the two nutrients supplied together compared with the treatment in which the two nutrients were separated. Roots proliferated in the compartment applied with either P or K at the expense of root growth in the adjoining compartment with neither P nor K. Heterogeneous nutrient distribution has a direct decreasing effect on root growth in deficient patches, and nutrient redistribution within the plant is unlikely to meet the demand of roots grown in such patches.  相似文献   

17.
Some disorders of the upper airway in humans are marked by decreased cross-sectional area and increased airway wall compliance. Based on our observations from studies performed in the isolated upper airway of dogs, we hypothesized that the size, and perhaps the geometry, of the airway was altered by changes in the relative activation levels of various muscle pairs. This could be accomplished either by altering the intensity of the neuromuscular input, or by activating muscle pairs which have different geometric orientation to the airway. We developed an analytic relationship to allow us to vary the stimulus level driving any one of six muscle pairs, each with a different anatomic orientation, to evaluate the relationship between those parameters and upper airway volume. With data generated from bilateral electrical stimulation of upper airway muscles, we described a shape factor which allowed us to predict the maximum force produced at optimal length. These findings were applied to a length/tension curve common to striated muscle to allow us to examine the muscle behavior at lengths other than optimal. The position of each muscle was described in spherical coordinates relative to an elastic cylinder, which represented the isolated, sealed upper airway. These coordinates defined the direction in which the force generated by each muscle pair would be applied. Three compliance constants determined the change in airway dimensions produced by the muscle force. This system and its variables were used to calculate the change in volume of the sealed upper airway chamber resulting from muscle contraction.(ABSTRACT TRUNCATED AT 250 WORDS)  相似文献   

18.
Cold hardened and unhardened 8- or 16-month-old citrus plants were examined for differences in fatty acid (FA) content. Unhardened leaves from 8-month-old Valencia scion budded on sour orange rootstock had 29% less FAs than leaves from seedling sour orange. After cold hardening triacylglycerol (TAG) FAs increased 4-fold in Valencia on sour orange and 6-fold in sour orange seedling. The percentage of FAs associated with TAGs for unhardened-hardened 16-month-old Valencia on sour orange tissues were: upper leaves 7–20, lower leaves 6–17, bark 6–9, and roots 57–73%. Cold hardening increased the amount of TAG FAs of 16-month-old Valencia on sour orange in upper leaves by 226% and in lower leaves by 173%. Concentrations of linoleic acid increased by 479% in upper leaves and by 303% in lower leaves. Quantities of lionolenic acid in monogalactosyl diacylglycerols declined by 27% in upper leaves and by 20% in lower leaves.  相似文献   

19.
Neurotensin-like immunoreactivity can be detected in extracts of canine upper gastrointestinal mucosa when measured by carboxyl terminal but not by amino terminal antibodies to neurotensin. The nature of this immunoreactive material was characterized by complete purification on gel filtration and HPLC followed by peptide microsequence analysis. The structure obtained was Glu-Asn-Lys-Pro-Arg-Arg-Pro-Tyr-Ile-(Leu), identical in structure to the carboxyl terminal decapeptide of neurotensin. It cannot, however, be excluded that this neurotensin decapeptide was generated from a larger neurotensin-like peptide during the extraction procedure by a physiological or artificial enzymatic process. Since carboxyl terminal neurotensin fragments containing eight or more residues have full biological activity, this peptide may be responsible for neurotensin-like biological activities within the mucosa of, or after release from, the upper gut.  相似文献   

20.
SUMMARY. 1. The vertical distribution within the substrate of three lotic mayflies (Rhithrogena sp., Paraleptophlebia sp. and Baetis tricaudalus Dodds) was examined in laboratory streams to determine if diel patterns of vertical movement across substrate surfaces existed and whether light intensity, temperature, substrate composition or food availability influenced the observed movement patterns.
2. Rhithrogena sp. and B. tricaudatus exhibited significant diel movement from lower substrate surfaces during the day to upper surfaces at night, although >64% of B. tricaudalus occupied the upper surfaces throughout the 24 h period. In contrast, Parakplophlebia sp. larvae did not change their vertical distribution over the 24 h period.
3. The proportion of mayflies occupying substrate surfaces was influenced by the amount of upper and lower surface area available in the substrate and, possibly, crevice sizes associated with lower surfaces.
4. The movement of Rhiihrogena sp. from lower surfaces during the day to the upper surfaces during the night was influenced by changes in light intensity, but not by changes in food availability or water temperature.
5. The diel patterns of vertical movement exhibited by lotic mayflies in this investigation raise the possibility that at least some biotic interactions may vary over a diel cycle. These could include competitive interactions or temporal cycling of prey availability to predators.  相似文献   

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