海军飞行员齿龈阿米巴感染情况的调查分析

为了解海军飞行员人群的齿龈阿米巴感染情况 ,我们对近年来院疗养的海军飞行员进行了临床调查一、对象与方法1.对象 :对 1998～ 2 0 0 0年来我院健康疗养的海军男性飞行员 375名 ,年龄 2 4～ 36岁。2 .方法 :使用消毒持针器在龈袋或牙周袋内勾划牙面上的软垢 ,置于有生理盐水的玻璃板上直接涂片 ,用 10× 40倍显微镜观察。检查时询问病史、刷牙方法和使用牙膏等情况 ,并作口腔疾病的检查和诊断。3.感染程度评价标准 :1轻度 :高倍镜下 11个以上视野查见一个虫体者中度 :高倍镜下 4～ 10个视野查见一个虫体者。3重度 :高倍镜下 1～ 3个视野查…     

海军高性能歼击机飞行员表象扫描加工水平研究

目的探讨飞行训练对飞行员表象扫描加工能力的影响。方法20名海军歼击机飞行员作为试验组，对照组为20名大学生及医师，在年龄、利手和文化程度上均与试验组相匹配。试验以反应时附加因素法研究范式测定，并以Kosslyn高水平视觉加工模型对表象扫描加工特性进行分析。结果除简单任务的反应时外，试验组与对照组相比在各表象扫描距离上的反应时和正确率均未表现出明显的优势。结论飞行员表象扫描加工的能力并不因系统的飞行训练而明显提高，提示该能力的可塑性较低。     

军事飞行员对比敏感度的分布特征

目的 探讨军事飞行员对比敏感度(CS)检查的结果分布特征.方法 应用美国Vector Vision公司生产的CSV-1000对比敏感度仪检查空军飞行员73例(146眼)明视、暗视和暗视眩光条件下不同空间频率(3、6、12、18cpd)的CS,分别对性别、眼别、机种不同空间频率的CS结果进行比较.结果 飞行员CS在中频区(6cpd)最高.左右眼比较、歼击机与运输机飞行员比较差异无统计学意义(P＞0.05).明视、暗视、暗视眩光CS依次呈下降趋势,除低频(3cpd)和高频(18cpd)暗视和暗视眩光比较差异无统计学意义,其他情况均有统计学差异(P＜0.05).女飞行员CS在多个频段均好于男飞行员,仅明视12cpd和18cpd差异无统计学意义(P＞0.05).结论本调查客观反映了军事飞行员CS的分布特征,为临床航空医学研究提供了较可靠的数据.     

CT screening for lung cancer: five-year prospective experience

PURPOSE: To report results of a 5-year prospective low-dose helical chest computed tomographic (CT) study of a cohort at high risk for lung cancer. MATERIALS AND METHODS: After informed written consent was obtained, 1520 individuals were enrolled. Protocol was approved by institutional review board and National Cancer Institute and was compliant with Health Insurance Portability and Accountability Act, or HIPAA. Participants were aged 50 years and older and had smoked for more than 20 pack-years. Participants underwent five annual (one initial and four subsequent) CT examinations. A significant downward shift was evaluated in non-small cell lung cancers detected initially from advanced stage down to stage I by using a one-sided binomial test of proportions. Poisson regression and Fisher exact tests were used for comparisons with Mayo Lung Project. RESULTS: In 788 (52%) men and 732 (48%) women, 61% (927 of 1520) were current smokers, and 39% were former smokers. After five annual CT examinations, 3356 uncalcified lung nodules were identified in 1118 (74%) participants. Sixty-eight lung cancers were diagnosed (31 initial, 34 subsequent, three interval cancers) in 66 participants. Twenty-eight subsequent cases of non-small cell cancers were detected, of which 17 (61%; 95% confidence interval: 41%, 79%) were stage I tumors. Diameter of cancers detected subsequently was 5-50 mm (mean, 14.4 mm; median, 10.0 mm). Analysis for a more than 50% shift in proportion of stage I non-small cell cancer detection did not show statistical significance. Forty-eight participants died of various causes since enrollment. Lung cancer mortality rate for incidence portion of trial was 1.6 per 1000 person-years. There was no significant difference in lung cancer mortality rates of cancers detected in subsequent examinations between this trial and Mayo Lung Project after separation of participants into subsets (2.8 vs 2.0 per 1000 person-years, P = .43). CONCLUSION: CT allows detection of early-stage lung cancers. Benign nodule detection rate is high. Results suggest no stage shift.     

Psychophysiological aspects of naval aviation pilots of the Navy in the operation of highly carrier-based aircraft

The authors have shown that the most difficult elements of the flight deck of the ship are springboard takeoff and aerofinishing landing. An important task is to study the aerodynamic characteristics of the behavior of the aircraft during takeoff different characteristics, forming crews ready to act in particular situations. Adverse factors are the operating conditions of habitability of aircraft (noise, vibration, fumes in the air at work, and aircraft engines, etc.) that have a significant impact on the life of air crew and engineering staff. It is concluded that the development and use of effective means of protecting the organism from the effect of these factors is a priority for specialists in aviation medicine.     

Contrast use: waste not--want not

Efficient use of low-osmolar contrast media is essential, owing to their cost and increasing substitution for conventional agents. A study was undertaken in three radiology departments to examine use of intravascular contrast media. Over a one-month period in the summer of 1987, the amount of intravascular contrast medium used and discarded was measured in one community hospital and two university-affiliated hospitals in southwestern Ontario. The major part of the waste occurred in the angiography suite, while minimal wastage was recorded in computed tomography. Much less contrast was wasted in the community hospital than in the teaching hospitals. Thirteen percent of all contrast material used by the three hospitals was discarded. Some wastage appears inevitable. Multidose dispensing systems as well as variety in bottle sizes have been proposed to reduce waste. Individual departments need to be aware of the problem and analyze their own patterns of contrast use.     

Reliable callosal measurement: population normative data confirm sex-related differences

BACKGROUND AND PURPOSE: Corpus callosal cross-sectional area (CCA) may be a clinical indicator of disease progression, but factors influencing callosal morphology in healthy subjects must be determined before comparisons can be made in patients. We sought to define a reliable and easily repeatable method for CCA measurement and to examine the effects of sex, age, handedness, and cerebral volume. METHODS: Neurologically healthy volunteers (age range, 14-68 years; mean age, 32.6 years +/- 12.3 [SD]; 44 men, 56 women; 87 right handed) underwent conventional MR imaging. Data were reoriented in the image space to account for intersubject variations in head position before the midsagittal plane was defined by using midpoints of the anterior commissure (AC), posterior commissure (PC), and interhemispheric fissure (IF). Midsagittal CCA and total cerebral volume were measured and correlated with sex, age, and handedness. RESULTS: The mean CCA was 6.27 cm(2) +/- 0.90. Women had a larger CCA proportional to cerebral volume (6.16 x 10(-3) cm(-1) vs 5.78 x 10(-3) cm(-1) in men; P =.02). The percentage difference for the CCA-cerebral volume from the group mean was +2.6% in women and -3.6% in men. Only a small linear relationship of CCA with cerebral volume was noted (r(2) = 0.15), and CCA was not significantly correlated with age or handedness. CONCLUSION: To our knowledge, this is the largest study of callosal area in a community-based sample of control subjects; such subjects provide controls for future studies. Our findings provide anatomic evidence of sex differences in interhemispheric connectivity. Much CCA variability is independent of cerebral volume.     

Guidelines for establishing a maternal serum alpha-fetoprotein screening program.

Maternal serum alpha-fetoprotein (MSAFP) screening of all pregnant women between 15 and 20 weeks gestational age is generally recognized as a standard of care in current obstetric practice. There are many factors to consider when deciding to establish MSAFP testing as an in-house procedure versus ship-out testing by a reference laboratory at fee-for-service cost. In this report, we review clinical and analytical aspects of MSAFP testing, along with appropriate guidelines for establishing an on-site MSAFP screening program.     

MR volumetric analysis of the human basal ganglia: normative data

RATIONALE AND OBJECTIVES: The authors undertook this study to identify a precise, semiautomated, reproducible magnetic resonance (MR) imaging technique for measuring the basal ganglia, to establish normative volumetric data, and to verify the presence of previously reported asymmetries. MATERIALS AND METHODS: Twenty-eight healthy adults underwent cranial MR examination. The volumes of the various components of the basal ganglia were measured by means of a combination of thresholding and manual tracing techniques performed with specialized software. The validity of these measurements was assessed by fashioning, imaging, and measuring a practical basal ganglia phantom. Measurement accuracy was also established by means of inter- and intrarater reliability indexes. Normalized volumes were statistically analyzed with analysis of variance and paired t tests. RESULTS: The absolute values of the various components of the basal ganglia varied widely even though the volumes were normalized to differences in intracranial volume. The right caudate nucleus volume was significantly (P < .000001) larger than the left in both men and women and in both right-handed and non-right-handed subjects. This asymmetry led to an increase in the overall volume of the basal ganglia on the right. CONCLUSION: The authors have defined a precise, reproducible technique for measuring various components of the basal ganglia and have established normative data. The basal ganglia, similar to other brain structures, exhibit hemispheric lateralization.     

Instrumented measurement of glenohumeral joint laxity: reliability and normative data

This study assessed shoulder laxity using an instrumented arthrometer. We compared anterior and posterior translations at various force levels to determine the reliability of our measurement technique and to provide normative data in healthy shoulders. Fifty shoulders were assessed for glenohumeral joint laxity in two directions (anterior and posterior) and at four force levels (67, 89, 111, and 134 N). The dependent measure was joint displacement. Laxity values were widely, yet normally, distributed in our group of healthy shoulders. Intraclass correlation coefficients revealed excellent between-trial reliability (0.92) and fair between-session (0.73) and between-examiner (0.74) reliability. The average standard error of measurement between trials (0.56 mm), sessions (1.5 mm), and examiners (1.7 mm) demonstrated an unprecedentedly high degree of precision for quantifying glenohumeral joint laxity. Paired t tests revealed no significant laxity differences between sides (P>0.05), indicating bilateral symmetry. A 2 (direction) x 4 (force) analysis of variance revealed significant differences in laxity between directions (P<0.0001) and force levels (P<0.0001). Our results show that our instrumented technique for quantifying glenohumeral joint laxity is precise and reproducible. Posterior translation was significantly greater than anterior, and a significant increase in translation was observed between increasing levels of force.     

Aerobatic flight effects on baroreflex sensitivity and sympathovagal balance in experienced pilots

BACKGROUND: Aerobatic flights subject pilots to accelerations and, therefore, to heavy physical workloads. OBJECTIVE: Our aim was to document changes in spontaneous baroreflex sensitivity and disturbances of sympathovagal balance after exposure to "push-pull" accelerations. METHODS: During 30-min flights, five aerobatic pilots performed five series of descending spirals: first, 30 s under negative (-3 Gz max), and then 30 s under positive (+4 Gz max) G loading, climbing between each series to regain altitude. A stand-test was performed before (T0), immediately postflight (PF), 1 h (PF1), and 2 h after (PF2) the flight. A Finapres apparatus recorded heart rate (HR) and BP during the stand-tests. RESULTS: Resting HR was higher at PF than T0 in supine (11.2 +/- 5.3%, p < 0.01) and standing (11.0 +/- 4.9%; p < 0.05) positions. Sequence analysis of spontaneous baroflex sensitivity (BRS) and spectral analysis of HR variability showed that: a) supine spontaneous BRS did not differ between preflight and postflight, while parasympathetic modulation of HR variability tended to increase; and b) supine spontaneous BRS was higher at PF1 than PF (PF: 0.011 +/- 0.0014 ms x mmHg(-1), PF1: 0.015 +/- 0.0012 ms x mmHg(-1); p < 0.05) and parasympathetic modulation of HR variability (high frequency component) was higher at PF2 than PF (PF: 0.014 +/- 0.007, PF2: 0.039 +/- 0.009; p < 0.001). CONCLUSIONS: These findings may reflect a change in the sympathovagal balance during the second hour of recovery from repeated push-pull maneuvers.     

The International Knee Documentation Committee Subjective Knee Evaluation Form: normative data

BACKGROUND: The International Knee Documentation Committee Subjective Knee Evaluation Form may be used to measure symptoms, function, and sports activity for people with a variety of knee disorders, including ligamentous and meniscal injuries, osteoarthritis, and patellofemoral dysfunction. To date, normative data have not been established for this valid, reliable, and responsive outcomes instrument. PURPOSE: To provide clinicians and researchers with normative data to facilitate the interpretation of results on the International Knee Documentation Committee Subjective Knee Evaluation Form. STUDY DESIGN: Cross-sectional survey. METHODS: The Subjective Knee Evaluation Form was mailed to 600 people in each of 8 age/gender categories (18-24 years, 25-34 years, 35-50 years, and 51-65 years for both male subjects and female subjects). Participants were drawn from a panel of 550 000 households (1 300 000 subjects) representative of noninstitutionalized persons in the United States and were matched to data from the United States Census Bureau on geographical region, market size, income, and household size. RESULTS: Complete data were available for 5246 knees. Twenty-eight percent of respondents reported an injury, weakness, or other problem with one or both knees. Normative data were determined for respondents as a whole and for the subset of respondents with no history of knee problems. Mean scores were determined for men aged 18 to 24 years (89 +/- 18), 25 to 34 years (89 +/- 16), 35 to 50 years (85 +/- 19), and 51 to 55 years (77 +/- 23); mean scores were also determined for women aged 18 to 24 years (86 +/- 19), 25 to 34 years (86 +/- 19), 35 to 50 years (80 +/- 23), and 51 to 65 years (71 +/- 26). Scores were higher for the subset of respondents with no history of current or prior knee problems. CONCLUSION: Scores on the International Knee Documentation Committee Subjective Knee Evaluation Form vary by age, gender, and history of knee problems. The normative data collected in this article will allow clinicians to interpret how patients with knee injuries are functioning relative to their age- and gender-matched peers and will enable researchers to determine the clinical outcomes of treatment.     

高性能战斗机飞行员加速度耐力选拔方法和标准的探讨

目前高性能战斗机飞行员的离心机选拔多采取“穿抗G服做抗G收紧动作”的综合加速度耐力鉴定方法。但在实际操作和准确评价时存在许多问题，有必要进一步探讨。我们对飞行员的离心机加速度耐力结果进行统计分析，计算不同抗G措施防护效果与基础G耐力的相关系数。结果表明：①加速度耐力不良者的基础G耐力明显低于健康飞行员，P＜0．01；②抗荷装备效能与基础G耐力密切相关；③抗G收紧动作的熟练程度与其效果相关；④采用综合措施能耐受9．0G的人基础G耐力≥4．5G；基础G耐力＜4．5G的人难以耐受9．0G。因此我们认为，高性能战斗机飞行员必须经过加速度耐力选拔，以基础G耐力达到快增长率4．5G持续10s为合格。     

Magnetization transfer imaging of the head and neck: normative data.

PURPOSETo determine magnetization transfer ratios for normal head and neck structures so that evaluation of disease will be possible.METHODSTwo-dimensional magnetization transfer imaging was performed in 12 healthy volunteers and 20 patients. We used a repetition time of 500, echo time of 12, 20 degrees flip angle, and a magnetization transfer pulse offset from the resonance frequency of water by 2000 Hz (pulse duration 19 milliseconds, waveform area approximately 10 times greater than that of a 90 degree pulse). Magnetization transfer ratios (1 - [intensity after suppression/intensity before suppression]) were calculated for normal structures.RESULTSThe magnetization transfer ratio of facial muscles (0.54) was equivalent to that of tongue muscles (0.54). These values exceeded those of parotid (0.39) and submandibular glands (0.41). Fat (0.07) and cerebrospinal fluid (0.05) had negligible transfer.CONCLUSIONMagnetization transfer imaging is a simple and effective means of studying the contribution of macromolecular protons to the MR image. Normal neck structures show a wide range of magnetization transfer rates, maximal for muscle and minimal for cerebrospinal fluid and fat.     

The development of postural control among children: Repeatability and normative data for computerized dynamic posturography system

BackgroundThe purpose of this study was to investigate the normal development of postural control in children aged 2–18 years in Tehran, and to provide normative data of computerized dynamic posturography (CDP) device variables.MethodsThe study population included 400 boys and 400 girls aged 2–18 years (eight age groups with 2-year interval) and 100 adults aged 22–25 years. In each age group, 100 people were selected based on the inclusion and exclusion criteria. To evaluate the postural control of the subjects, the sensory organization test (SOT) was performed by using a CDP.ResultsThe results of this study led to the determination and presentation of normative data for the development of postural control in boys, girls and children aged 2–18 years. The results related to the repeatability of data produced by the CDP, thereby showing that this system is highly reliable. The results of an independent t-test also showed that girls across all age groups performed better than boys (p ≤ 0.05).ConclusionThe results of this study demonstrated a nonlinear trend of natural development of postural control. Overall, according to the results of the present study, it seems that like adults, 14–16 year-old teens are capable of processing, integrating and organizing sensory systems information for postural control.     

Intravenous digital subtraction renal angiography: use in screening for renovascular hypertension

Intravenous digital subtraction renal angiography (DSRA) has been compared with conventional angiography only in small, selected series of hypertensive patients. The authors prospectively examined with intravenous DSRA 94 patients at increased risk for renovascular hypertension and compared these studies with conventional angiography. A stenosis of at least one main renal artery was identified with intravenous DSRA in 22 patients and confirmed in 20 patients. No significant stenoses were seen with conventional angiography in any of the 64 patients in whom lesions were not seen with intravenous DSRA. Since inadequate DSRA studies were considered positive for renal artery stenosis, the sensitivity of intravenous DSRA was 100% (25 of 25); specificity, 93% (64 of 69); positive predictive value, 83% (25 of 30); and negative predictive value, 100% (64 of 64). The authors conclude that intravenous DSRA is a sensitive test for identifying stenosis of the main renal arteries and is appropriate to use as a screening test among patients at increased risk for renovascular hypertension.