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1.
OBJECTIVE: The insulin stress test (IST) is the most commonly used test to assess the GH reserve in children and adults. It is a time-consuming, expensive and potentially dangerous test. We investigated whether measurement of urinary growth hormone excretion following exercise would prove on reliable method to diagnose adult GH deficiency. DESIGN: Healthy volunteers underwent a standard IST to confirm GH secretion. Using a standardized exercise protocol on a treadmill, the urinary excretion of GH was measured. Three patients confirmed as GH deficient by an IST were exercised during the same exercise protocol and their urinary excretion of GH was measured. PATIENTS: Ten healthy volunteers and three patients with hypopituitarism were evaluated. MEASUREMENTS: A standard IST was performed on both healthy volunteers and patients, with measurements of plasma GH and plasma cortisol. Urinary growth hormone and urinary GH/creatinine (GH/CR) ratios were measured before and after IST. On a separate visit, healthy volunteers and patients were exercised on the treadmill with measurements of plasma GH and cortisol. Urinary GH and GH/CR ratios were measured before and after exercise. RESULTS: There was at least a two-fold increase in urinary GH and GH/CR ratios following exercise in all healthy adults. By contrast, patients with GH deficiency showed no rise in urinary GH or urinary GH/CR ratios following exercise. CONCLUSIONS: Measurements of urinary GH following exercise can distinguish between GH-deficient adults and healthy volunteers. Urinary GH excretion can be measured over a timed interval following exercise or can be expressed as the GH/CR ratio. This can be measured on a single sample following exercise and can be used to diagnose GH deficiency. The exercise test employed for this study is arduous. We are therefore performing further studies with a less strenuous exercise protocol with a view to designing a 'patient-friendly' exercise test for GH deficiency in adults.  相似文献   

2.
Echo-planar techniques in MRI use a rapidly oscillating frequency-encoding gradient with the potential to produce peripheral nerve stimulation. To evaluate the incidence, type, and location of stimulation in a commercial whole-body scanner, we studied two groups: (a) 173 consecutive individuals scanned by echo-planar imaging for other purposes and (b) seven subjects who were scanned with an extensive set of 36 echo-planar sequences (with prompting after each scan to report any peripheral nerve stimulation) to test the effects of various parameters. Although only 5% of group A reported symptoms of peripheral nerve stimulation, all in group B experienced some type of stimulation, dependent primarily on direction of the oscillating gradient and location of the body within the gradient coil. Maximum stimulation typically occurred 30 to 40 cm from isocenter in the region of maximum dB/dt. Generally, y gradients produced truncal stimulation, and x gradients produced stimulation in the head. When hands were clasped over the abdomen, a tingling in the hands occasionally was felt. Patients should be instructed to keep their hands apart.  相似文献   

3.
The experimental concept and findings from a recent manned orbital spaceflight are described. Together with ongoing terrestrial and parabolic studies, the present experiment is intended to further our knowledge of the sensory integrative processing of information from the semicircular canals and the otolithic receptors, and to quantify the presumed otolithic adaptation to altered gravito-inertial force environments in a more reliable manner than to date. The experiment included measurement of the basic vestibulo-oculomotor response during active head rotation about each of the three orthogonal axes. Priority was given to the recording of ocular torsion, as elicited by head oscillation about the roll axis, and thus due to the concomitant stimulation of the semicircular canals and otolith receptors. Videooculography was employed for the measurement of eye movements; head movement was measured by three orthogonally arranged angular rate sensors and a triaxial linear accelerometer device. All signals were recorded synchronously on a video/data recorder. Preliminary results indicate alterations in the torsional VOR under zero-g conditions, suggesting an adaptive modification of the torsional VOR gain over the course of the 6-day orbital flight. In addition, the inflight test findings yielded discrepancies between intended and performed head movement, indicating impairment in sensorimotor coordination under prolonged microgravity conditions.  相似文献   

4.
AIM: To determine reproducibility and accuracy of the Nikon Retinomax autorefractor when used with children who were made cycloplegic. METHODS: Autorefraction and retinoscopy or subjectively refined retinoscopy (where, under the patient's direction, the refraction was varied until the best visual acuity was achieved) were performed on the right eye of 47 children, age 11-93 months. Autorefraction was performed using the Nikon Retinomax, which provides up to eight measured values of refractive error and one representative measurement of refractive error. RESULTS: Autorefractor measurements were successfully obtained from 7/9 children age 3 years or younger, and from all older children. Vector methods were used to calculate differences. Retinomax reproducibility averaged 0.43 D. Unbiased Retinomax and retinoscopy measurements differed by an average of 0.82 D. Unbiased Retinomax and subjectively refined retinoscopy differed by an average of 1.03 D. CONCLUSIONS: Reproducibility of Retinomax measured values in children is comparable with reproducibility of retinoscopy, subjective refraction, and autorefraction measurements in adults. Agreement between Retinomax and retinoscopy and agreement between Retinomax and subjective refinement in children is comparable with agreement between autorefraction and subjective refraction in adults. The study indicates that the Retinomax is a useful instrument for measuring refractive errors in young children.  相似文献   

5.
Aim of the present study was to evaluate the effect of acute hyperglycemia on peripheral nerve conduction measurements. Five healthy male volunteers aged 36-42 years underwent nerve conduction studies during hyperglycemia (blood glucose approximately 12 mmol/l) induced by intravenous infusion of glucose and maintained for 120 minutes. Peroneal motor and sural sensory nerve conduction velocities and amplitudes were measured from the right leg at 15 min intervals starting at 15 min before and continuing 30 min after glucose infusion. Data were analysed using paired t-test comparing measurements at each time point after the start of the infusion to the second control measurement immediately prior to the infusion. All nerve conduction velocities and amplitudes were similar before, during and after induced hyperglycemia. The results suggest that it is unnecessary to standardise blood glucose concentration during measurement of peripheral nerve functions.  相似文献   

6.
> Objective: For more than 20 years, vibroacoustic stimulation testing (VAST) using an artificial larynx has been used worldwide when fetal heart rate monitoring produced patterns with absent or very low variability. In addition to the artificial larynx many other appliances have been used to stimulate a seemingly dormant fetus, but these have rarely been evaluated properly. In this study we tried to evaluate the use of standard mechanical wind-up alarm clocks for VAST. Methods: VAST with an alarm clock was performed successfully in 80 women with normal pregnancies from 36 weeks to term. It was tested by placing the alarm clock on the maternal abdomen just above the fetal head or on the controlateral side of the maternal abdomen to see whether position made any difference and whether coupling with ultrasound gel applied between the alarm clock and the maternal abdomen would affect the degree of fetal reaction to VAST as expressed in heart rate acceleration. Similarly, the effect of the alarm clock VAST on subjective and objective fetal movement patterns as registered by kineto-cardiotocotraphy (K-CTG) in addition to heart rate patterns was investigated. Results: All fetuses showed heart rate acceleration, an increase in heart variability, and increase in movement patterns in the 6 min after the application of alarm clock VAST. No statistically significant difference was found which would favor a particular placement of the alarm clock on the maternal abdomen or the use of ultrasound coupling gel. When K-CTG was performed, patient-perceived fetal movements as expressed with an event marker showed agreement with the machine-registered movements only when patients could see the tracing during registration and no accordance when the K-CTG was turned toward the wall during registation. Conclusion: In keeping with the ALARA principle a conventional wind-up alarm clock appears to be an inexpensive and effective alternative to the electrolarynx.  相似文献   

7.
The growth of the body was studied in 30 human fetuses ranged from 10 to 22 weeks of gestation. The fetuses were fixed by immersion in 4 percent formaldehyde and the following dimensions were studied: a) lengths: arm, forearm, hand, thigh, leg, foot and crown-rump (sitting height), b) perimeters: head, thorax and abdomen. A covariance matrix was calculated from natural logarithms of all measurements. The relative growth of these measurement was computed by multivariate allometry using a principal components analysis (PCA). All characters were positively correlated with the first principal component which accounted for 94.65 per cent of the total variance. Considering the different measurements in the sequence of the increasing growth rates no one was considered to increase in isometric relationship. PCA showed that the following measurements grew with negative allometry: head perimeter, C-R length, thoracic perimeter, length of the forearm and abdominal perimeter. On the other hand, the following lengths grew with positive allometry: hand, foot, thigh, arm and leg. In conclusion, during the first two trimesters of prenatal life the growth of the body is allometrical. Limbs increase with greater growth rates than the perimeters of the body cavities.  相似文献   

8.
OBJECTIVE: Considerable evidence exists to suggest that tumor hypoxia results in radioresistance. Historically, it has been difficult to assess tumor oxygen tension levels reliably. These levels can now be assessed in head and neck malignancies using the Eppendorf pO2 histograph, which uses a fine-needle electrode and a computerized micromanipulator. This technology was used to compare the pretreatment tumor oxygen tension level in lymph node metastases of patients with head and neck cancer to measurements taken during nonsurgical treatment after a partial response had been achieved. STUDY DESIGN: Prospective study. METHODS: Oxygen tension levels were measured in the cervical lymph nodes of 10 patients with biopsy-proven head and neck squamous cell carcinoma and cervical metastases who were being treated with nonsurgical management. These levels were obtained using the Eppendorf pO2 histograph system. Measurements were taken before the start of treatment and were repeated when the size of the cervical metastatic node had decreased by 50%. Normal subcutaneous tissue was measured during the same session. The mean and median pO2 levels, as well as the percentage of measurements with pO2 less than 5 mm Hg were determined. RESULTS: A mean of 72.6 measurements per session was taken from each lymph node. The median tumor pO2 measurement fell from a mean (+/-SD) of 13.9+/-8.0 mm Hg to 7.3+/-9.9 mm Hg. Even more dramatic, however, was the substantial increase in the percentage of values less than 5 mm Hg, a rise from 29% to 52%. CONCLUSIONS: While there is variability both in the pretreatment oxygenation of head and neck cervical metastases and in the change in tumor oxygen tension during treatment, there appears to be a decrease in the overall oxygenation of the tumors. The dramatic increase in very low oxygen measurements may reflect selective survival of radioresistant or chemoresistant hypoxic tumor cells. Cells at the very low level would be expected to be radiobiologically hypoxic (resistant to radiation-induced cell kill).  相似文献   

9.
PURPOSE: To distinguish 24-hour (circadian) and postural effects on intraocular pressure (IOP) in healthy young adults. METHODS: Thirty-three volunteers were housed in a sleep laboratory for 1 day under a strictly controlled 16-hour light and 8-hour dark environment. Sleep was encouraged in the dark period. Intraocular pressure was measured in each eye every 2 hours using a pneumatonometer. Researchers used night-vision goggles to perform IOP measurements in the dark, while the subject's light exposure was minimized. In the first group of 12 subjects, measurements were taken with subjects in the sitting position during the light-wake period and supine during the dark period. In the second group of 21 subjects, all IOP measurements were taken with the subjects supine. RESULTS: Average IOP was significantly higher in the dark period than in the light-wake period in both groups. The lowest IOP occurred in the last light-wake measurement, and the peak IOP occurred in the last dark measurement. The trough-peak difference in IOP was 8.2+/-1.4 mm Hg (mean +/- SEM) in the first group. Intraocular pressure changed sharply at the transitions between light and dark. In the second group, the trough-peak IOP difference was 3.8+/-0.9 mm Hg. Intraocular pressure changed gradually throughout the 24-hour period. In comparison with the sitting IOP in the first group, the supine IOP in the second group was significantly higher during the light-wake period. CONCLUSIONS: Circadian rhythms of IOP were shown in young adults, with the peaks occurring in the late dark period. A nocturnal IOP elevation can appear independent of body position change, but change of posture from upright to recumbent may contribute to the relative nocturnal IOP elevation.  相似文献   

10.
STUDY DESIGN: Repeated measurements were made of surface postural angles registering the relative positions of the head and neck in photographs and of angles of the upper cervical vertebrae recorded in lateral cephalometric radiographs in the same subjects. For all registrations, subjects assumed the natural head rest position. OBJECTIVES: To examine the correlation between external measurement of head and neck posture and the anatomic positions of the upper four cervical vertebrae. SUMMARY OF BACKGROUND DATA: Interpretation of surface cervical posture measurement is confounded by lack of knowledge about the extent of the underlying compensatory adjustments among the upper cervical vertebrae that may accompany variation in head and neck posture. The correlation between surface measurement and postural characteristics of the upper cervical spine has not been reported to date. METHODS: The association between a set of angles describing the anatomic position of the four upper cervical vertebrae on lateral cephalometric radiographs and a surface measurement of head and neck posture, the craniovertebral angle, was studied in 34 young adult women aged between 17.2 and 30.5 years, mean age, 24.5 years. Anatomic positions of the upper four cervical vertebrae were expressed by angles relative to the true vertical or horizontal. Surface angles registering head and neck position for each subject were obtained from photographs recorded on two occasions. RESULTS: No strong correlation could be established between the angles taken from the lateral cephalometric radiographs measuring the extent of upper cervical lordosis, orientation of the atlas, vertebral inclination, or odontoid process tilt and surface angles recording head and neck position. This finding was attributed principally to the much greater positional variability demonstrated within the upper cervical spine when compared with the surface measurements of head and neck position. CONCLUSION: Anatomic alignment of the upper cervical vertebrae cannot be inferred from variation in surface measurement of head and neck posture. This is the case even in those people identified with more extreme head and neck postural tendencies.  相似文献   

11.
Head flexion and extension movements near the natural head position (NHP) were analysed for the location of the mean instantaneous centre of rotation (ICR). Forty-six healthy young adults (30 women and 16 men) with sound dentitions, free from cranio-cervical disorders, performed habitual movements that were automatically detected and measured by an infrared three-dimensional motion analyser. ICR and curvature radius were calculated for each movement and subject. In both extension and flexion, ICR position changed during the motion. The movement was symmetrical in all subjects. No gender or flexion/extension differences were found for both ICR position and relevant curvature radius. On average, ICR relative to NHP soft-tissue nasion was located at about 150% of the soft-tissue nasion-right tragus distance, with an angle of about 220 degrees relative to the true horizontal. Results suggest that head flexion or extension is always performed with a combination of rotation (atlanto-occipital joint) and translation (cervical spine) even in the first degrees of motion. Moreover, NHP at rest seems to be some degree more flexed and anterior than head position during movements. These relative positions and their muscular determinants could also influence mandibular posture at rest and during functional movements.  相似文献   

12.
In 11 healthy subjects motor-evoked potentials (MEPs) and silent periods (SPs) were measured in the right first dorsal interosseus (FDI) and abductor pollicis brevis muscles (APB): (1) when transcranial magnetic cortex stimulation (TMS) was applied at tonic isometric contraction of 20% of maximum force, (2) when TMS was applied during tactile exploration of a small object in the hand, (3) when TMS was applied during visually guided goal-directed isometric ramp and hold finger flexion movements, and (4) when at tonic isometric contraction peripheral electrical stimulation (PES) of the median nerve was delivered at various intervals between PES and TMS. Of the natural motor tasks, duration of SPs of small hand muscles was longest during tactile exploration (APB 205+/-42 ms; FDI 213+/-47 ms). SP duration at tonic isometric contraction amounted to 172+/-35 ms in APB and 178+/-31 ms in FDI, respectively. SP duration in FDI was shortest when elicited during visually guided isometric finger movements (159+/-15 ms). At tonic isometric contraction, SP was shortened when PES was applied at latencies -30 to +70 ms in conjunction with TMS. The latter effect was most pronounced when PES was applied 20 ms before TMS. PES-induced effects increased with increasing stimulation strength up to a saturation level which appeared at the transition to painful stimulation strengths. Both isolated stimulation of muscle afferents and of low-threshold cutaneous afferents shortened SP duration. However, PES of the contralateral median nerve had no effect on SPs. Amplitudes of MEPs did not change significantly in any condition. Inhibitory control of motor output circuitries seems to be distinctly modulated by peripheral somatosensory and visual afferent information. We conclude that somatosensory information has privileged access to inhibitory interneuronal circuits within the primary motor cortex.  相似文献   

13.
PURPOSE: To compare the reproducibility of laser interferometric measurements of fundus pulsation, pneumatonometric measurement of pulse amplitude (PA) and pulsatile ocular blood flow (POBF), and Doppler ultrasonic measurements of blood flow velocity in the ophthalmic artery (OA) and the posterior ciliary arteries (PCAs) and to investigate the association of the results obtained with these methods and to characterize ocular hemodynamics during Valsalva maneuver and isometric handgrip. METHODS: All studies were performed in healthy subjects. Fundus pulsation (n = 48), POBF (n = 24), and blood flow velocities (n = 24) were measured at baseline and during the Valsalva maneuver and isometric handgrip. Intraclass correlation coefficients were calculated for test/retest variability, for short-term variability, and for interobserver variability. RESULTS: Intraclass correlation coefficients were between 0.95 and 0.98 for fundus pulsation measurements, between 0.54 and 0.76 for pneumatonometric measurements, between 0.44 and 0.88 for Doppler sonographic measurements in the OA and between 0.32 and 0.60 in the PCAs. There was a high degree of association between pneumatonometric parameters and fundus pulsation amplitude. Valsalva maneuver significantly reduced fundus pulsations, PA, and POBF, whereas isometric handgripping did not change these parameters. CONCLUSIONS: The reproducibility of fundus pulsation measurements was excellent. Reproducibility of pneumatonometric parameters and ultrasonographic measurements in the OA was satisfactory. Reproducibility of ultrasonographic measurements in the PCAs was low. Data obtained during the autonomic stimuli experiments argue against the sole use of systems to measure pulsatile blood flow, if no additional data on flow pulsatility are available. At least in cases when changes in blood pressure are likely to occur the ratio of pulsatile to nonpulsatile blood flow might not be constant and POBF might not be an adequate measure of total ocular blood flow.  相似文献   

14.
The purpose of this study was to s the value of MRI for measurement of pulmonary autograft diameters after transplantation to the aortic root in adults. Thirty-eight adults underwent this operation. MRI and transesophageal echocardiography (TEE) were performed in 30 and 27 patients, respectively, after a mean follow-up period of 2.8 years. For internal validation of MRI, measurements at the diastolic short and long axes of the sinus level were used. Pulmonary autograft diameters were measured and compared with MRI and TEE at five different levels: the subannular region (1), annulus (2), sinus (3), sinotubular junction (4), and the distal part of the autograft (5). The correlation coefficient (r2) between long- and short-axis measurements for corresponding sinuses was .97. Diameters obtained with MRI were 1 to 3 mm larger than those obtained with TEE (P < .05), except for the annulus at systole (P > .3). Cine gradient echo MRI is an appropriate technique to evaluate pulmonary autograft diameters during follow-up. Concordance with TEE was good, apart from a systematic difference of approximately 2 mm.  相似文献   

15.
A maximum-likelihood confirmatory factor analysis was performed by applying LISREL VII to the Wechsler Adult Intelligence Scale—Revised (D. Wechsler, 1981) results of a normal elderly sample (N?=?225). Analyses were designed to determine which of seven hypothesized factor solutions best explained the intellectual ability of older adults. Oblique and orthogonal solutions were tested for each of the factor models. The impact of age, education, and gender was examined. Results indicated that an oblique three-factor model including Verbal, Performance, and Freedom From Distractibility factors fit the best across all sample combinations. A mild gender effect was also evident. Picture Arrangement measured both Verbal and Performance characteristics in the female sample, whereas in the male sample, Picture Arrangement loaded on the Performance factor only. (PsycINFO Database Record (c) 2010 APA, all rights reserved)  相似文献   

16.
17.
PURPOSE: To integrate a newly developed OLCR instrument into the optical system of the excimer laser. The instrument is designed to perform corneal pachymetry before, during, and after corneal photoablation and thus allow for a precise and continuous on-line measurement of the corneal photoablation process. METHODS: The conditions required to integrate the OLCR instrument into the excimer laser optics were investigated. With a technical setting providing on-line data of corneal thickness, three groups of 8-10 corneae received central keratectomies of 27 (group 1), 82 (group 2) and 163 (group 3) microns calculated central depth and 7.38 mm diameter. All measurements were performed with OLCR and ultrasound. RESULTS: The OLCR instrument was coupled into the optical system of the excimer laser and a useful signal obtained at SLD power levels of 40 microW incident on the cornea. Individual corneal thickness measurements were obtained before, during and after the photoablation procedure. In group 1, the ablation was 50.3 (40-68) microns measured with ultrasound and 30.2 (27-38) microns measured with OLCR. In group 2, the ablation was 101.1 (80-113) microns measured with ultrasound and 93.3 (76-109) microns measured with OLCR. In group 3, the ablation was 210.6 (190-227) microns measured with ultrasound and 188.4 (181-197) microns measured with OLCR. The precision (standard deviation) for measurements of individual corneas was 1-2 microns with OLCR and up to 12 mm in Ultrasound measurements. CONCLUSION: With this interferometric method, continuous, non-contact measurement of corneal thickness before, during and after excimer laser photoablation were performed. By establishing a feed-back control between the pachymetric measurements and the photoablation process, the precision of excimer ablation may possibly be further increased.  相似文献   

18.
OBJECTIVE: The human body is often exposed to significant vibration stress in the workplace, at home, and during recreational activities. The current study was designed to evaluate whether low- to midfrequency vibrations present at the extraabdominal wall would be attenuated across this wall and what the levels of exposure would be once these vibrations reached the fetal head. STUDY DESIGN: Four pregnant sheep were instrumented with acceleration transducers to obtain acceleration levels at the extraabdominal and intraabdominal walls and at the fetal head. Sine-wave vibration stimulation was applied over a frequency range of 3 to 150 Hz at a constant acceleration level of 2.5 m/sec2 (root-mean-square). RESULTS: Vibration of the extraabdominal wall resulted in a frequency-dependent rise in vibration levels at the intraabdominal wall, from 4% to 140% of the input level. At the fetal head a broad peak in response was noted between 6 and 12 Hz, but the overall levels never exceeded 4% of the input level. CONCLUSION: Fetal exposure to localized vibratory stimulation of the maternal abdomen is maximal in the range of 6 to 12 Hz.  相似文献   

19.
To study the analgesia efficacy of drugs combined with acupuncture analgesia for painless labor, 462 normal pregnancy women were observed. During the latent phase in labor, several analgesia methods: acupuncture analgesia, analgesics, magnetotherapy and auricular acupressure, TENS combined with dihydroetorphine were used respectively. While the intrauterine pressure and the peripheral content of beta-EP were measured during labor, the experiments of SEPS were also performed on healthy adults to demonstrate the analgesia efficacy of those analgesia methods. The combination of drugs with acupuncture is an excellent method for painless labor without any complications and all the mothers and babies are safety. The effectiveness is 97.5%. The results demonstrate that the mechanism of analgesia efficacy should be regulated the incoordinate uterine action and improve the hypertonic status of uterus, but also can decrease the pain threshold and elevate the tolerance of uterine contractions during labor.  相似文献   

20.
Despite recent advances in imaging techniques for endocrine tumors of the duodenum and the pancreas, preoperative localization of gastrinomas is inconsistent. Successful surgical management of patients with Zollinger-Ellison syndrome (ZES) and removal of all gastrin-secreting tumors remains a difficult task. The aim of the study was to evaluate the predictive value of intraoperative gastrin measurements for successful surgical treatment in patients with gastrinomas. Intraoperative gastrin measurements were performed in 20 patients with ZES who underwent resection of gastrin-secreting tumors. Gastrin was measured with a radioimmunologic assay in blood samples obtained from a peripheral vein and from the portal vein at the beginning of the operation (T0) and 20 minutes after removal of the lesion(s) (T1). In 16 patients gastrin was also measured 4 minutes after injection of secretin 3 U/kg (T2). Thirteen patients (65%) were cured by surgery. In two of them, peripheral and portal gastrin levels were normal at T0, precluding any further interpretation of the test. Completeness of surgery was confirmed by normalization of gastrin levels at T1 or the absence of stimulation at T2 (or both) in 10 patients. In only one case did the gastrin levels remain elevated at T1 despite a favorable outcome after surgery. In each of the seven patients (35%) who had persisting disease at 1 year, failure of the surgical procedure was predicted by persistence of high levels of gastrin at T1. In patients with hypergastrinemia, the positive predictive value of intraoperative gastrin measurement for completeness of surgery and the specificity were 100%. The negative predictive value was 88% and the sensitivity 91%. The overall accuracy of the test was 94%. In patients with ZES the normalization of systemic hypergastrinemia during surgery affirms the successful removal of all gastrin-secreting tumors. We conclude that intraoperative gastrin measurement is a valuable addendum for optimizing the surgical management of gastrinoma.  相似文献   

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