Leukotriene-B4 concentrations in breathing condensate before and after simulated deep dives.

During diving the respiratory tract is exposed to occupational hazards (increased oxygen partial pressure, pulmonary vessel engorgement during submersion, inert gas micro embolism during decompression). Leukotriene-B4 [LTB4] concentrations in the exhaled breath mirrors the inflammatory activity of the airways if the respiratory tract has been exposed to occupational hazards. In this study LTB4-concentrations in the exhaled breath and spirometry data obtained before and after simulated dives helped to elucidate any contributions by hyperbaric exposure to impaired lung function and to separate effects of ambient pressure from those of submersion and increased oxygen partial pressure. Thirty two healthy subjects carried out dives in a hyperbaric chamber using a cross over design to 600 kPa ambient pressure with and without submersion and a dry exposure to pure oxygen at 120 kPa ambient pressure (durations: 43 min). Pre-dive and four hours after surfacing the exhaled breath was collected non-invasively. Condensate was measured by a standard enzyme immuno-assay for LTB4 in parallel with lung function values (FVC, FEV1, MEF 25-75). Pre-exposure baseline values of LTB4-concentrations and lung function values were in the normal range. Post-exposure values did not differ significantly from the baseline values. The data gave no evidence of any inflammatory activity in the subjects' airways after hyperbaric exposure.     

Direct ascent from air and N2-O2 saturation dives in humans: DCS risk and evidence of a threshold.

To estimate the risk of decompression sickness (DCS) for direct ascents from depth to the sea surface for personnel who are saturated with hyperbaric nitrogen, we analyzed 586 experimental air or nitrogen-based saturation dives. No DCS occurred on shallow saturation dives between 12.0 and 20.5 feet of seawater, gauge (fswg) but incidence of DCS rose abruptly when depth was deeper than 20.5 fswg, reaching 27% at 30 fswg. This is evidence of a threshold for clinical DCS. A model based on a Hill function that provides for a threshold predicts the observations better than a model having no threshold provision; the no-threshold model overestimates risk shallower than 20.5 fswg and underestimates risk between 20.5 and 30 fswg. For situations such as submarine rescues, we recommend our threshold model when the exposure pressure is 33 fswg or less. We also discuss deeper dives where there are no human data; extrapolations can be quite different for models that provide for a threshold than for models that do not.     

Clinical observation: Beau's lines on fingernails after deep saturation dives.

Transverse furrows, or Beau's lines, were noted in the fingernails of all 6 divers following a deep saturation dive to apressure equal to 1100 feet (335 meters) ofsea water (3,370 kPa), and in 2 of6 divers following a similar dive to 1000 feet (305 meters) of sea water (3,164 kPa). Both dives took place at the Ocean Simulation Facility of the Navy Experimental Diving Unit in Panama City, Florida. The divers breathed a partial pressure of 0.40 - 0.44 atm abs (40.5 - 44.6 kPa) oxygen, with the balance helium, during most of the time under pressure. All divers performed hard work on bicycle ergometers during the dives. Four of the divers on the first dive were treated during the dive for pain-only decompression sickness. Beau's lines have been reported in numerous medical conditions such as typhus, rheumatic fever, malaria, myocardial infarction, and other severe metabolic stresses. To the author's knowledge this is the first report of Beau's lines associated with saturation diving.     

The relationship between venous gas bubbles and adverse effects of decompression after air dives.

The presence of gas bubbles in the vascular system is often considered a sign of decompression stress and several studies in the existing literature have addressed the relationship between the amount of bubbles detected by ultrasound Doppler systems and the incidence of decompression sickness. The use of ultrasound imaging has some important advantages to Doppler systems, and here we have looked at the relationship between the amount of intravascular gas bubbles detected by ultrasound echocardiography and the incidence of signs and symptoms of decompression stress after 203 air dives. The results show that venous gas bubbles detected by ultrasound imaging is a highly sensitive, although not specific, predictor of such adverse effects of decompression. Our results agree with the published concordance between Doppler detected bubbles and decompression sickness. We conclude that bubble detection by ultrasonic scanning of the heart can be used as a tool to assess the safety of decompression procedures for air dives.     

Isoproterenol accelerates decompression sickness and death after saturation dives in swine

BACKGROUND: Disabled submarine (DISSUB) survivors are expected to achieve inert gas tissue saturation that would likely cause severe decompression sickness (DCS). Rescue procedures in a DISSUB scenario cannot accommodate a staged decompression and the availability of recompression treatment chambers is limited. Alternatives to the standard recompression procedures for treating DCS are needed. Experimentally, isoproterenol has successfully addressed many underlying physiological concerns expected to result in cardiopulmonary DCS in this group. HYPOTHESIS: We hypothesized that isoproterenol would reduce the incidence of cardiopulmonary DCS in a saturation dropout model. METHODS: Yorkshire swine (21.8 +/- 1.68 kg) were fitted with an external jugular catheter and compressed to 4.33 ATA in a dry chamber for 22 h. They were infused with isoproterenol (0.002 mg x kg(-1)) while still at depth and returned to the surface without decompression stops. They received additional infusions every 10 min throughout a 2-h observation period. Signs of DCS were recorded to the nearest minute. RESULTS: Isoproterenol administration resulted in a significant increase in the incidence of severe cardiopulmonary DCS (13/34 control vs. 12/18 isoproterenol) and death from DCS (10/34 control vs. 11/18 isoproterenol). There was no difference in the incidence of severe neurological DCS. CONCLUSIONS: Administering isoproterenol as an intervention/treatment for DCS significantly increases the risk of cardiopulmonary DCS and death following saturation dropout in 20-kg swine. As an adjunctive therapy or alternative to staged decompression, isoproterenol in the dose regimen delivered here is not expected to improve outcome in a DISSUB mass casualty scenario.     

Hysterography before and after myomectomy.

Pre- and postmyomectomy hysterograms were compared in 12 consecutive cases. In 11 cases, the uterine cavity was of normal shape and size after surgery, irrespective of the degree of preoperative uterine distortion. In two cases fallopian tubes were not visualized before surgery but were found patent after removal of the fibroids. In all cases studied, preoperative hysterography was valuable in confirming the presence and localization of myomata but of limited value in predicting the feasibility of the procedure.     

Graves病治疗前后细胞因子水平的变化

目的　探讨1 31 I和抗甲状腺药物 (ATD)治疗对Graves病 (GD)患者血清细胞因子水平及免疫功能的不同影响。方法　用放射免疫分析法检测 87例接受ATD治疗、14 6例接受1 31 I治疗的GD患者治疗前及治疗后 30 ,6 0 ,180和 36 0d外周血清白细胞介素 2 (IL 2 )、白细胞介素 6 (IL 6 )、肿瘤坏死因子 (TNF α)浓度变化 ,并与血清FT3、FT4 、促甲状腺激素 (TSH)进行相关性分析。结果　GD患者血清IL 6、TNF α水平显著高于对照组 (P <0 0 1) ,IL 2显著低于对照组 (P <0 0 1) ;血清IL 6与TNF α水平呈正相关 (P <0 0 5 ) ,与IL 2、FT3、FT4 、TSH水平无相关性 ;1 31 I治疗与ATD治疗对GD患者血清细胞因子的影响程度不一致。结论　1 31 I和ATD治疗可影响血清细胞因子的表达。多种细胞因子水平变化与病程和治疗结果密切相关。     

新训战士功能性消化不良治疗前后胃肠激素水平变化的研究

 目的探讨武警新训战士中功能性消化不良(Functional dyspepsia,FD)患者应用多潘立酮、马来酸曲美布汀及安慰剂的治疗效果及其胃动素(MTL)、胆囊收缩素(CCK)的变化水平,探索特殊人群中FD的发病特点和不同治疗方案的效果.方法确诊为FD的新兵随机分为多潘立酮组,马来酸曲美布汀组和安慰剂组,治疗前填写FD症状自评量表、检测血浆MTL、CCK水平,治疗2周后复查血浆MTL、CCK水平并填写FD症状自评量表.结果三组患者FD评分治疗后明显低于治疗前(P＜0.01),三组患者血浆MTL水平低于正常人群,CCK水平高于正常人群;各组治疗后血浆MTL水平明显上升(P＜0.05),治疗后血浆CCK水平仅马来酸曲美布汀组较治疗前明显下降(P＜0.01).结论促动力药治疗特殊人群FD的效果可靠,同时安慰剂治疗也可取得较好的疗效;FD的发生和MTL、CCK水平变化相关.     

Complement and immunoglobulin levels in athletes and sedentary controls

Eleven marathon runners (42.7 +/- 2.1 yrs, 54.2 +/- 1.8 ml.kg-1.min-1) and nine sedentary controls (44.2 +/- 1.2 yrs, 33.3 +/- 1.1 ml.kg-1.min-1) were studied during 30 min of rest, a graded maximal treadmill test using the Balke protocol, and 45 min of recovery to determine the effects of training and acute exercise on complement and immunoglobulin levels. Three baseline and five recovery blood samples were obtained in addition to repeated 5-min samples during exercise. Data for the exercise period were analyzed using a multiple regression approach to repeated measures ANOVA to allow comparison between groups on a percent VO2max basis. Groups did not differ during any of the three phases for IgG, IgA, or IgM. Resting levels of complement C3 (0.89 +/- 0.05 vs 1.27 +/- 0.10 g/L, P less than 0.001) and C4 (0.19 +/- 0.02 vs 0.29 +/- 0.03 g/L, P less than 0.001) were significantly lower in athletes than in controls. Exercise complement C3 [F(1,18) = 14.1, P = 0.001] and C4 [F(1,18) = 7.6, P = 0.013], and recovery complement [F(1,18) = 19.4, P less than 0.001] and C4 [F(1,18) = 13.5, P = 0.002] were also lower in the athletes than in sedentary controls. Acute increases during exercise were not associated with changes in catecholamines or cortisol. These data suggest that blood concentrations of C3 and C4, but not IgG, IgA, or IgM, are decreased during rest, graded maximal exercise, and recovery in marathon runners in comparison with sedentary controls.     

多样化军事任务的应激环境对部队官兵心理状态及皮质醇水平的影响

目的探讨多样化军事任务部队官兵SCL-90的评定及消化道疾病相关激素水平的变化。方法采用症状自评量表(SCL-90)对执行常规训练、爆破、伞兵作业军事人员269人进行任务完成前后调查及放射免疫法检测血清皮质醇浓度。结果爆破、伞兵军事人员任务完成后SCL-90各项因子分值均低于完成前,其中躯体化、焦虑、抑郁、精神病性因子分下降较明显(P<0.01),其次是恐怖因子分值下降(P<0.05),其他因子未达到显著水平。任务完成后血清皮质醇浓度均较任务完成前显著升高(P<0.01),常规训练组前后变化不明显。结论多样化军事任务的应激环境对部队官兵心理状态及内分泌激素变化的影响有明显不同,严重的军事应激可引发或加重部队官兵胃肠道疾病以及引起血清皮质醇水平升高,常规训练应激反应较平缓,故应加强多样化军事应激不同人群的对应处理。     

子宫动脉栓塞术前后性激素水平的变化

目的　探讨子宫动脉栓塞术前后性激素的变化。方法　对 2 7例子宫肌瘤进行子宫动脉栓塞治疗 ,测定术前后黄体生成素 ,促卵泡素 ,雌二醇等水平。结果　促卵泡素术前为 (8.6 3± 10 .33)IU/L ,术后 3个月 (15 .8± 2 7.89)IU/L ;促黄体生成素术前 (11.77± 12 .2 1)IU/L ,术后 3个月 (2 5 .79±37.2 4 )IU/L ;雌二醇术前 (16 0± 6 7) pg/ml,术后 3个月 (184± 87) pg/ml(P >0 .0 5 ,t检验 )。手术前后黄体生成素 ,促卵泡素 ,雌二醇差异无显著性 ;其中 2例出现绝经期的变化。结论　子宫动脉栓塞对性激素影响不大。     

Gait analysis of walking before and after medial opening wedge high tibial osteotomy

Introduction

Medial opening wedge high tibial osteotomy (HTO) is used to treat medial compartment osteoarthritis (OA) of the knee. HTO shifts the weight-bearing line from the medial compartment into the lateral compartment. The aim of this study was to investigate the functional biomechanical consequences of this alteration in alignment.

Methods

Eleven male patients with medial compartment osteoarthritis underwent three-dimensional gait analysis during level walking before 12 months and after medial opening wedge HTO. Nine male control subjects of a similar age were also tested using the same protocol. Sagittal and coronal angles and moments in both operated and non-operated knees were compared. Pre and postoperative radiographic coronal plane alignment was also measured.

Results

Walking speed increased significantly postoperatively (P = 0.0001) and was not different from controls. Preoperatively, maximum knee flexion in stance was reduced compared to control (P = 0.02). Postoperatively, maximum knee flexion increased significantly (P = 0.005) and was the same as the controls. Similar changes were observed for the maximum knee flexion moment. The mean maximum varus angle during stance was reduced from 13.5° preoperatively to 5.4° postoperatively (P = 0.0001) compared to (6.8°) in controls. The mean maximum adduction moment also reduced from 3.9 to 2.7 (% Bw/ht, P = 0.02), compared to 3.6 in control subjects. Interestingly, the adduction moments in the non-operated knee increased postoperatively from 3.3 to 4.1 (% Bw/ht, P = 0.02). The mean radiological mechanical alignment was changed from 172 degrees preoperatively to 180 degrees postoperatively (P < 0.001).

Conclusion

HTO resulted in normalisation of several dynamic knee function parameters such as walking speed, knee flexion and external knee flexion moment. As anticipated, HTO reduced the varus angle and adduction moments of the operated knee. An increased adduction moment in the non-operated knee over the first postoperative year was found.

Level of evidence

Prospective case–control clinical laboratory study, Level III.     

Physiological risk factors for falls in people with knee osteoarthritis before and early after knee replacement surgery

Purpose  

Knee osteoarthritis (OA) is a major cause of disability and a risk factor for falls in older people. The purpose of this study was to assess the falls risk of people with knee OA before surgery and at 4 months following surgery and to compare this to a control group.     

Infectious episodes before and after a marathon race

The aim of this study was to investigate the incidence of self-reported infectious episodes (IE) during 3 weeks before (pre-IE) and 3 weeks after (post-IE) a marathon race and relate these figures to training status, running time, socioeconomic and demographic factors. Two questionnaires, including questions about important factors for IE incidence, were given to a representative cohort of 1694 runners (17% of all finishers) in the Stockholm Marathon 2000. Pre-IE incidence in the cohort was 17% with no difference between women and men. Post-IE incidence in the whole cohort was 19% with no significant (P>0.05) difference between women and men. The post-IE incidence in runners without a pre-IE was 16% (P>0.05 to pre-IE incidence). In the group of runners with pre-IE, 33% experienced an IE after the race also (P<0.05 to Pre-IE incidence). A logistic regression analysis showed that younger age and pre race health status and, for men only, experienced nausea during and after the race were depended factors explaining post-IE incidence. Younger runners were more prone to experience IE both before and after the race. There was no relation between training volume 6 months before the race, finishing time and socioeconomic and demographic factors and pre-IE or post-IE. This study does not support the theory of increased infection rate after exhaustive long-distance running ("The Open Window Theory") in recreational runners, but suggests that the sometimes experienced increased rate of infections among athletes can be caused by strenuous exercise too soon after an infection.     

Serial dacryoscintigraphy before and after treatment with pseudoephedrine

Radionuclide dacryoscintigraphy is an accurate physiologic method for evaluating the nasolacrimal drainage apparatus. The following case report illustrates the role of this procedure in the initial workup of epiphora, as well as its value in assessing response to therapy with pseudoephedrine.     

Assessment of the H‐reflex at two contraction levels before and after fatigue

The aim of the present study was to compare the H‐reflex evoked at rest and at 20% maximal voluntary contraction (MVC) prior to and after fatiguing the lateral gastrocnemius (LG). The maximal H‐reflex and M‐wave were recorded in the LG, and soleus (SOL). Electrical evoked potentials were delivered to the posterior tibial nerve when muscles were inactivated and at 20% MVC. After fatigue, the H_max/M_max ratio of the fatigued LG was increased for both contraction levels (rest and 20% MVC) and remained unaltered for non‐fatigued SOL. Before fatigue, the H_max/M_max ratio of SOL was enhanced at rest compared with the H_max/M_max ratio at 20% MVC. No differences were observed for LG. Fatigue of a single muscle leads to increased spinal reflex activity of the homonymous muscle. Contrary to previous recommendations in the literature, there appears to be no benefit with regard to the H‐reflex amplitude in evoking electrical potentials during constant voluntary contractions at 20% MVC compared with inactivated muscles. The observed difference in SOL prior to fatigue was most likely due to hyperpolarization of the muscle fiber membrane.