Evaluation of pancreatic circulation by duplex color Doppler flow sonography.
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Follow-Up Studies↗
Biomedical subjects
J C Young
Publications and source records attributed to J C Young.
Acute mortality associated with injuries to the pelvic ring: the role of early patient mobilization and external fixation.
PURPOSE: To analyze the effect on mortality of a protocol for early mobilization with external fixation of patients with pelvic ring injuries. METHODS: From 1981 through 1988, 605 patients with pelvic ring fractures and dislocations were treated. In 1982, a protocol for early external fixation of hemodynamically unstable patients and those with structurally unstable pelvic fracture patterns to achieve early mobilization to an upright chest position was initiated. Mortality rates were compared between 1981 (pre-protocol), 1982 (transitional), and 1983 through 1988, after initiation of a protocol of care that included external fixation of the pelvic injury. No statistical changes occurred from 1983 through 1988. RESULTS: Mortality rates in pelvic ring injury patients fell from 26% in 1981, to 6% in 1983 through 1988 (p < 0.001), whereas during the study period the mean injury Severity Score (ISS), 23, did not change. The mortality rate of a group of consecutive patients with comparable ISSs, but without pelvic ring injuries did not change. The mortality rate in patients with systolic blood pressure < 100 mm Hg at admission fell from 41% in 1981 to 21% 1983 through 1988 (p = 0.0001). Mortality in patients with closed head injuries associated with pelvic ring injuries fell from 43% in 1981 to 7% from 1983 through 1988 (p = 0.0001). The proportion of patients undergoing external fixation rose from 3% in 1981 to 31% in 1983 through 1988 (p = 0.0001). CONCLUSIONS: An organized protocol including external fixation and early patient mobilization to an upright chest position reduced mortality associated with injuries of the pelvic ring. Orthopedic stabilization of major skeletal injuries should be viewed as part of patient resuscitation, not reconstruction.
Clinical Protocols↗
Synergy of IL-7 and v-Ha-ras in the in vitro neoplastic progression of murine pre-B cells.
A recombinant retrovirus expressing IL-7 was superinfected into a murine pre-B cell line previously infected with a retrovirus expressing v-Ha-ras. Populations of cells polyclonal for integration of the IL-7 virus and independent of IL-7 for growth were generated. These cells were highly tumorigenic. Similarly, co-infection of murine bone marrow with retroviruses expressing IL-7 and v-Ha-ras generated a pre-B lymphoid outgrowth that was tumorigenic. While IL-7 and v-Ha-ras expression are not individually sufficient to induce tumorigenicity, their co-expression yields highly tumorigenic pre-B lymphoid cell lines. IL-7 expression may be equivalent to v-myc expression for synergy with v-H-ras in the neoplastic transformation of murine pre-B cells.
3T3 Cells↗
Supercritical fluid chromatography of Fusarium mycotoxins.
Capillary- and packed-column supercritical fluid chromatography has been used for the separation of Fusarium mycotoxins of various structure types such as the trichothecenes including deoxynivalenol and its acetylated derivatives and T-2 toxin, as well as butenolide, culmorin, sambucinol and zearalenone. The effect of modifier concentration and column temperature and pressure was also studied. Retention indices based on alkylphenones were determined for these mycotoxins on two of the capillary columns employed.
Capillary Action↗
The role of the N region in signal sequence and signal-anchor function.
To determine the role of sequences other than the hydrophobic core in mediating signal sequence function, we examined the behavior of fusion proteins and deletion mutants in cell-free systems. We demonstrate that neither the N nor the C region of the preprolactin signal sequence is necessary for translocation. However, insertion of sequences with either a net charge of +2.5 or -6.0 between the N region and the hydrophobic core of the signal converted it into a signal-anchor. The topologies adopted (types I and II, respectively) were opposite those predicted from the distribution of charges surrounding the hydrophobic core of the signals. When these mutant signals were located in the interior of an otherwise secreted protein, both sequences functioned as stop-transfer sequences. Related mutations were assayed in fusion proteins in which the IgM transmembrane domain functioned as an amino-terminal signal-anchor. For these molecules, the distribution of charged residues surrounding the hydrophobic core had no influence on the topology adopted. Our results suggest that features other than simple charge distribution play an important role in determining membrane topology in vitro.
Amino Acid Sequence↗
Effects of contaminants of macrobenthic communities in the upper Calcasieu Estuary, Louisiana.
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Animals↗
The effect of prior exercise on oral glucose tolerance in late gestational women.
Glucose tolerance deteriorates over the course of a normal human pregnancy as a result of increased peripheral insulin resistance. In contrast, physical exercise has been shown to improve glucose tolerance and blunt the insulin response to a glucose load in insulin-resistant individuals. The purpose of this study was to determine the effect of exercise on glucose tolerance and the insulin response in healthy women during the third trimester of pregnancy (33 weeks of gestation). Five subjects underwent oral glucose tolerance tests (a) 30 min following a 30-min exercise bout on a cycle ergometer at a relative intensity of 50% maximal aerobic capacity, and (b) on a control day without prior exercise. The area under the glucose concentration curve was not different between trials, while the area under the insulin concentration curve was decreased by 23% in the exercise trial compared with the control trial (P less than 0.05). These results suggest that the insulin response to a glucose load is improved in late gestational women by a single bout of moderate intensity exercise.
Administration, Oral↗
Skeletal muscle glucose uptake following overload-induced hypertrophy.
While endurance exercise training has been shown to enhance insulin action in skeletal muscle, the effects of high resistance strength training are less clear. The purpose of this study was to determine the rate of glucose uptake in skeletal muscle in which compensatory hypertrophy was induced by synergist muscle ablation. Basal and insulin mediated [3H] 2-deoxyglucose uptake were measured in soleus and EDL muscles using the perfused rat hindquarter preparation. Neither basal nor insulin mediated glucose uptake, when expressed per gram muscle, were enhanced in hypertrophied soleus muscles compared with control muscles, despite a twofold increase in mass (P less than 0.01). In the EDL, muscle mass increased 60% with synergist ablation (P less than 0.01), however insulin mediated glucose uptake was not different from that of control muscles. The basal rate of glucose uptake in hypertrophied EDL muscles was increased twofold over that of control muscles (P less than 0.05), possibly due to changes in neural input and/or loading. These results suggest that the stimulus for development of increased muscle mass is different from that for metabolic adaptations.
Analysis of Variance↗
Adaptation in synergistic muscles to soleus and plantaris muscle removal in the rat hindlimb.
Although the soleus muscle comprises only 6% of the ankle plantar flexor mass in the rat, a major role in stance and walking has been ascribed to it. The purpose of this study was to determine if removal of the soleus muscle would result in adaptations in the remaining gastrocnemius and plantaris muscles due to the new demands for force production imposed on them during stance or walking. A second purpose was to determine whether the mass or the fiber type of the muscle(s) removed was a more important determinant of compensatory adaptations. Male Sprague-Dawley rats underwent bilateral removal of soleus muscle, plantaris muscle, or both muscles. For comparison, compensatory hypertrophy was induced in soleus and plantaris muscles by gastrocnemius muscle ablation. After forty days, synergist muscles remaining intact were removed. Mass, and oxidative, glycolytic, and contractile enzyme activities were determined. Despite its role in stance and slow walking, removal of the soleus muscle did not elicit a measurable alteration in muscle mass, or in citrate synthase, lactate dehydrogenase, or myofibrillar ATPase activity in gastrocnemius or plantaris muscles. Similarly, removal of the plantaris muscle, or soleus and plantaris muscles, had no effect on the gastrocnemius muscle, suggesting that this muscle was able to easily meet the new demands placed on it. These results suggest that amount of muscle mass removed, rather than fiber type, is the most important stimulus for compensatory hypertrophy. They also suggest that slow-twitch motor units in the gastrocnemius muscle play an important role during stance and locomotion in the intact animal.
Adaptation, Physiological↗
The use of transesophageal echocardiography in the evaluation of chest trauma.
Transesophageal echocardiography (TEE) has been used over the last 10 years (1982-1992) to study the heart and thoracic aorta. We set out to evaluate the diagnostic applications of TEE in patients with thoracic trauma. Specifically, TEE was performed on patients suspected of having either a cardiac contusion or an injury of the thoracic aorta. Fifty-eight patients admitted with thoracic trauma underwent TEE. Fifty of those patients suspected of having a cardiac contusion also underwent transthoracic echocardiography (TTE). The two diagnostic modalities were compared. In 21 of these patients a wide mediastinum was apparent on admission chest x-ray films. Nineteen of this latter group underwent thoracic angiography in addition to TEE. Two patients underwent post-mortem examination. Of the 50 patients undergoing both TEE and TTE, a cardiac contusion was detected by TEE in 26 patients. Transthoracic echocardiography detected only six contusions in this group. Of the 21 patients with a wide mediastinum, TEE detected three obvious aortic disruptions. These findings were confirmed in each case by angiography. In 16 cases TEE showed the aorta to be normal. This was confirmed on the angiogram in 14 cases and by autopsy in two cases. Transesophageal echocardiography revealed an aortic intimal irregularity distal to the left subclavian artery in two cases. The results of aortography were normal in these last two cases. As a diagnostic modality, TEE more accurately detected cardiac contusions than TTE (p less than 0.001) and was a very sensitive screening tool in the early evaluation of patients with a wide mediastinum.
Adolescent↗
Genetic separation of phototropism and blue light inhibition of stem elongation.
Blue light-induced regulation of cell elongation is a component of the signal response pathway for both phototropic curvature and inhibition of stem elongation in higher plants. To determine if blue light regulates cell elongation in these responses through shared or discrete pathways, phototropism and hypocotyl elongation were investigated in several blue light response mutants in Arabidopsis thaliana. Specifically, the blu mutants that lack blue light-dependent inhibition of hypocotyl elongation were found to exhibit a normal phototropic response. In contrast, a phototropic null mutant (JK218) and a mutant that has a 20- to 30-fold shift in the fluence dependence for first positive phototropism (JK224) showed normal inhibition of hypocotyl elongation in blue light. F1 progeny of crosses between the blu mutants and JK218 showed normal phototropism and inhibition of hypocotyl elongation, and approximately 1 in 16 F2 progeny were double mutants lacking both responses. Thus, blue light-dependent inhibition of hypocotyl elongation and phototropism operate through at least some genetically distinct components.
Arabidopsis↗
Effect of prior exercise and insulin on potential thermogenic systems in rat skeletal muscle.
We previously reported that insulin stimulates oxygen consumption by the perfused rat hindquarter after high-intensity exercise. The purpose of the present study was to examine whether fructose 6-phosphate-fructose 1,6-bisphosphate cycling or an uncoupling of mitochondrial respiration contributes to this phenomenon. Hindquarter skeletal muscle was analyzed after perfusion in the absence or presence of insulin (150-200 microU/ml) for high-energy phosphate content, fructose 6-phosphate-fructose 1,6-bisphosphate cycling of glucose before incorporation into glycogen, and mitochondrial respiratory control. Muscle from exercised rats perfused with insulin did not display greater rates of glucose cycling or mitochondrial uncoupling; in fact, insulin decreased the rate of fructose 6-phosphate cycling and tended to increase respiratory control in skeletal muscle mitochondria. In addition, the concentrations of ATP and creatine phosphate and the calculated free ADP level in muscle of previously exercised rats perfused with insulin were similar to those of control rats. The results do not exclude the possibility that localized subcellular changes in ADP occurred, however. In conclusion, the results suggest that insulin-induced increases in other substrate cycles, ion transport systems, and/or as yet unidentified energy-requiring processes account for the 25-30% increase in hindquarter oxygen consumption after intense exercise.
Animals↗
Time-lapse analysis of gravitropism in Ceratodon protonemata.
The tip cell of the protonema of the moss Ceratodon purpureus (Hedw.) Brid. is negatively gravitropic when grown in the dark on supplemented agar. Gravitropism, plastid distribution, and plastid movement were studied in living cells using time-lapse video microscopy and infrared light. A wrong-way (downward) curvature preceded upward curvature and was detected as early as 2 minutes after reorientation. Upward curvature began 30-45 minutes after reorientation to the horizontal. Cell division temporarily reversed upward curvature, but did not inhibit wrong-way curvature. Since significant amyloplast sedimentation always occurred before the start of upward curvature, it is possible that these amyloplasts function as statoliths for upward curvature. However, no significant amyloplast sedimentation occurred before wrong-way curvature. Thus, this early phase of gravitropism cannot require plastid sedimentation for gravity sensing. Most plastids moved within and between zones, and plastid zonation was highly dynamic. Plastids moved toward the apex and toward the base of the cell at rates much slower than cytoplasmic streaming. Despite the dynamic nature of plastid movement and zonation, during upward curvature the distance between sedimented plastids and the apex stayed constant. Time-lapse analysis has revealed intriguing events not readily seen previously using destructive sampling.
Cell Cycle↗
Transesophageal echocardiography.
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Echocardiography↗
Defining the major trauma patient and trauma severity.
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Diagnosis-Related Groups↗
Ageing, exercise and food restriction: effects on skeletal muscle glucose uptake.
We investigated the effects of ageing, exercise and food restriction on glucose uptake by muscles perfused with physiological concentrations of insulin and glucose in male Long-Evans rats. The rate of glucose uptake by hindlimb muscles perfused with medium containing 50 microU@ml insulin and 8 mM glucose was the same in 9-10 month-, 18 month-, and 24-month-old rats. Rats exercised by means of swimming 3 h/day, 5 days/week, had significantly higher rates of muscle glucose uptake than did the sedentary freely eating rats. Paired-weight sedentary rats, that were food restricted so as to keep their weights in the same range as those of the swimmers, had a hindlimb glucose uptake rate similar to that of the swimmers, and greater than that of the sedentary freely eating rats. The 24-month-old sedentary freely eating rats showed a trend toward a higher plasma glucose response and a lower plasma insulin response to a glucose tolerance test. The 24-month-old swimmers showed no deterioration in glucose tolerance compared to the 9-10 month-old rats. Our findings argue against the concept that ageing results in skeletal muscle insulin resistance in rats.
Aging↗
Skeletal muscle atrophy in old rats: differential changes in the three fiber types.
This study was undertaken to reevaluate the effects of ageing on skeletal muscle mass and on mitochondrial and glycolytic enzyme levels in the different types of skeletal muscle in rats. It was found that some muscles atrophy with ageing, while others do not, in male rats. Atrophy appears to occur in weight-bearing muscles, and is most marked in those with a high proportion of type IIb fibers. The muscles that did not atrophy are non-weight-bearing, and include the epitrochlearis (predominantly type IIb fibers) and the adductor longus (predominantly type I fibers). The average cross-sectional area of muscle fibers in the plantaris muscles of 28-30-month-old rats was approximately 30% smaller than that of 9-10-month-old animals, providing evidence that the approximately 30% lower weight of the plantaris in the old group was entirely due to fiber atrophy. The proportion of type IIa fibers was decreased and the proportion of type I fibers was increased in the plantaris of the old rats. The respiratory capacity of the soleus muscle (predominantly type I fibers), and the glycolytic capacity of the superficial, white (type IIb) and deep, red (predominantly type IIa) portions of the vastus lateralis, were reduced in the old rats. Our results provide evidence that ageing has differential effects on the three types of skeletal muscle fiber, and on weight-bearing and non-weight-bearing muscles, in the rat.
Aging↗
Transesophageal echocardiographic examination of a patient with traumatic aortic transection from blunt chest trauma: a case report.
Traumatic aortic disruption is an injury associated with high mortality. Early recognition, diagnosis, and surgical repair are important in order to salvage patients with this injury. We report a case in which transesophageal echocardiography, a rapid, minimally invasive diagnostic technique, was used to identify an acute disruption of the proximal descending aorta in a patient with blunt chest trauma.
Adult↗