Acetazolamide or dexamethasone use versus placebo to prevent acute mountain sickness on Mount Rainier.

Eighteen climbers actively ascended Mount Rainier (elevation 4,392 m) twice during a randomized, double-blind, concurrent, placebo-controlled, crossover trial comparing the use of acetazolamide, 250 mg, dexamethasone, 4 mg, and placebo every 8 hours as prophylaxis for acute mountain sickness. Each subject was randomly assigned to receive placebo during one ascent and one of the active medications during the other ascent. Assessment of acute mountain sickness was performed using the Environmental Symptoms Questionnaire and a clinical interview. At the summit or high point attained above base camp, the use of dexamethasone significantly reduced the incidence of acute mountain sickness and the severity of symptoms. Cerebral and respiratory symptom severity scores for subjects receiving dexamethasone (0.26 +/- 0.16 and 0.20 +/- 0.19, respectively) were significantly lower than similar scores for both acetazolamide (0.80 +/- 0.80 and 1.20 +/- 1.05; P = 0.25) and placebo (1.11 +/- 1.02 and 1.45 +/- 1.27; P = .025). Neither the use of dexamethasone nor that of acetazolamide measurably affected other physical or mental aspects. Compared with placebo, dexamethasone appears to be effective for prophylaxis of symptoms associated with acute mountain sickness accompanying rapid ascent. The precise role of dexamethasone for the prophylaxis of acute mountain sickness is not known, but it can be considered for persons without contraindications who are intolerant of acetazolamide, for whom acetazolamide is ineffective, or who must make forced, rapid ascent to high altitude for a short period of time with a guaranteed retreat route.     

Simulated descent v dexamethasone in treatment of acute mountain sickness: a randomised trial.

OBJECTIVE--Evaluation and comparison of the therapeutic efficacy of a portable hyperbaric chamber and dexamethasone in the treatment of acute mountain sickness. DESIGN--Randomised trial during the summer mountaineering season. SETTING--High altitude research laboratory in the Capanna Regina Margherita at 4559m above sea level (Alps Valais). SUBJECTS--31 climbers with symptoms of acute mountain sickness randomly assigned to different treatments. INTERVENTIONS--One hour of treatment in the hyperbaric chamber at a pressure of 193 mbar or oral administration of 8 mg dexamethasone initially, followed by 4 mg after 6 hours. MAIN OUTCOME MEASURES--Symptoms of acute mountain sickness (Lake Louise score, clinical score, and AMS-C score) before one and about 11 hours after beginning the different methods of treatment. Permitted intake of mild analgesics before treatment and in the follow up period. RESULTS--After one hour of treatment compression with 193 mbar caused a significantly greater relief of symptoms of acute mountain sickness than dexamethasone (Lake Louise score: mean (SD) -4.6 (1.9) v -2.5 (1.8); clinical score: -4.0 (1.2) v -1.5 (1.4); AMS-C score: -1.24 (0.51) v -0.54 (0.59)). In contrast after about 11 hours subjects treated with dexamethasone suffered from significantly less severe acute mountain sickness than subjects treated with the hyperbaric chamber (-7.0 (3.6) v -1.6 (3.0); -4.1 (1.9) v -1.0 (1.5); -1.78 (0.73) v -0.75 (0.82) respectively). Intake of analgesics was similar in both groups. CONCLUSION--Both methods were efficient in treatment of acute mountain sickness. One hour of compression with 193 mbar in the hyperbaric chamber, corresponding to a descent of 2250 m, led to short term improvement but had no long term beneficial effect. On the other hand, treatment with dexamethasone in an oral dose of 8 mg initially followed by 4 mg every 6 hours resulted in a longer term clinical improvement. For optimal efficacy the two methods should be combined if descent or evacuation is not possible.     

Amelioration of acute mountain sickness: Comparative study of acetazolamide and spironolactone

Acetazolamide and spironolactone were evaluated for their ameliorating effects on acute mountain sickness (AMS). Studies were conducted in 29 healthy male subjects in lowland and at a height of 3,500 m after their airlift. A modified General High Altitude Questionnaire (GHAQ) was used to evaluate the effectiveness of these drugs for reducing the intensity of AMS symptoms. Both the drugs were found to be helpful in minimising the occurrence as well as severity of most of the symptoms. Spironolactone seems to be a superior prophylactic agent than acetazolamide.     

Successful treatment of acute mountain sickness with dexamethasone.

A double blind, randomised, placebo controlled trial of treatment with dexamethasone for acute mountain sickness was performed in the Capanna "Regina Margherita" at an altitude of 4559 m in the Alps Valais. After 12-16 hours of treatment (8 mg dexamethasone initially, followed by 4 mg every six hours) the mean acute mountain sickness score decreased significantly from 5.4 to 1.3, and eight of 17 patients became totally asymptomatic. Mean arterial oxygen saturation rose from 75.5% to 82.0%, and there was a small increase in standard spirometric measurements. In the placebo group none of these variables changed significantly. It is concluded that dexamethasone may be used as emergency treatment for acute mountain sickness to facilitate safe descent to a lower altitude.     

Acute Mountain Sickness Symptom Severity at the South Pole: The Influence of Self-Selected Prophylaxis with Acetazolamide

Introduction

Acetazolamide, a carbonic anhydrase inhibitor, remains the only FDA approved pharmaceutical prophylaxis for acute mountain sickness (AMS) though its effectiveness after rapid transport in real world conditions is less clear.

Methods

Over 2 years, 248 healthy adults traveled by airplane from sea level (SL) to the South Pole (ALT, ~3200m) and 226 participants provided Lake Louise Symptom Scores (LLSS) on a daily basis for 1 week; vital signs, blood samples, and urine samples were collected at SL and at ALT. Acetazolamide was available to any participant desiring prophylaxis. Comparisons were made between the acetazolamide with AMS (ACZ/AMS) (n = 42), acetazolamide without AMS (ACZ/No AMS)(n = 49), no acetazolamide with AMS (No ACZ/AMS) (n = 56), and the no acetazolamide without AMS (No ACZ/No AMS) (n = 79) groups. Statistical analysis included Chi-squared and one-way ANOVA with Bonferroni post-hoc tests. Significance was p≤0.05.

Results

No significant differences were found for between-group characteristics or incidence of AMS between ACZ and No ACZ groups. ACZ/AMS reported greater LLSS, BMI, and red cell distribution width. ACZ/No AMS had the highest oxygen saturation (O₂Sat) at ALT. No significant differences were found in serum electrolyte concentrations or PFT results.

Discussion

Acetazolamide during rapid ascent provided no apparent protection from AMS based on LLSS. However, it is unclear if this lack of effect was directly associated with the drug or if perhaps there was some selection bias with individuals taking ACZ more likely to have symptoms or if there may have been more of perceptual phenomenon related to a constellation of side effects.     

Mechanisms of action of acetazolamide in the prophylaxis and treatment of acute mountain sickness.

Acetazolamide, a potent carbonic anhydrase (CA) inhibitor, is the most commonly used and best-studied agent for the amelioration of acute mountain sickness (AMS). The actual mechanisms by which acetazolamide reduces symptoms of AMS, however, remain unclear. Traditionally, acetazolamide's efficacy has been attributed to inhibition of CA in the kidneys, resulting in bicarbonaturia and metabolic acidosis. The result is offsetting hyperventilation-induced respiratory alkalosis and allowance of chemoreceptors to respond more fully to hypoxic stimuli at altitude. Studies performed on both animals and humans, however, have shown that this explanation is unsatisfactory and that the efficacy of acetazolamide in the context of AMS is likely due to a multitude of effects. This review summarizes the known systemic effects of acetazolamide and incorporates them into a model encompassing several factors that are likely to play a key role in the drug's efficacy. Such factors include not only metabolic acidosis resulting from renal CA inhibition but also improvements in ventilation from tissue respiratory acidosis, improvements in sleep quality from carotid body CA inhibition, and effects of diuresis.     

Effects of acetazolamide and dexamethasone on cerebral hemodynamics in hypoxia

Previous attempts to detect global cerebral hemodynamic differences between those who develop headache, nausea, and fatigue following rapid exposure to hypoxia [acute mountain sickness (AMS)] and those who remain healthy have been inconclusive. In this study, we investigated the effects of two drugs known to reduce symptoms of AMS to determine if a common cerebral hemodynamic mechanism could explain the prophylactic effect within individuals. With the use of randomized, placebo-controlled, double-blind, crossover design, 20 healthy volunteers were given oral acetazolamide (250 mg), dexamethasone (4 mg), or placebo every 8 h for 24 h prior to and during a 10-h exposure to a simulated altitude of 4,875 m in a hypobaric chamber, which included 2 h of exercise at 50% of altitude-specific VO(2max). Cerebral hemodynamic parameters derived from ultrasound assessments of dynamic cerebral autoregulation and vasomotor reactivity were recorded 15 h prior to and after 9 h of hypoxia. AMS symptoms were scored using the Lake Louise Questionnaire (LLQ). It was found that both drugs prevented AMS in those who became ill on placebo (~70% decrease in LLQ), yet a common cerebral hemodynamic mechanism was not identified. Compared with placebo, acetazolamide reduced middle cerebral artery blood flow velocity (11%) and improved dynamic cerebral autoregulation after 9 h of hypoxia, but these effects appeared independent of AMS. Dexamethasone had no measureable cerebral hemodynamic effects in hypoxia. In conclusion, global cerebral hemodynamic changes resulting from hypoxia may not explain the development of AMS.     

Acetazolamide and Dexamethasone in the Prevention of Acute Mountain Sickness

We randomly assigned 32 healthy backpackers to receive placebo, acetazolamide (250 mg twice a day), dexamethasone acetate (4 mg four times a day), or both drugs in combination to determine the drug efficacy in preventing acute mountain sickness (AMS) at altitudes of 3,650 to 4,050m (12,000 to 13,300 ft). The incidence of AMS was high but symptoms were generally mild. Combined drug therapy was superior to both placebo and single drug therapy in risk reduction. Using acetazolamide alone was moderately beneficial in preventing the occurrence of AMS, although minor side effects were frequent. The use of dexamethasone alone did not significantly reduce the AMS incidence, and discontinuing its use resulted in symptoms suggestive of adrenal insufficiency. For recreational backpackers, routine drug prophylaxis is not recommended, in view of the mild nature of this illness and the adverse effects of medications. The efficacy of combined acetazolamide-dexamethasone therapy warrants further investigation at higher altitudes, where AMS is more severe, and the dexamethasone should be withdrawn gradually to avoid a possible adrenal crisis.     

Elevational Distribution and Ecology of Small Mammals on Africa’s Highest Mountain

Mt Kilimanjaro is Africa’s highest mountain, and an icon for a country famous for its mammalian fauna. The distribution and abundance of small mammals on the mountain are poorly known. Here we document the distribution of shrews and rodents along an elevational gradient on the southeastern versant of Kilimanjaro. Five sites were sampled with elevational center points of 2000, 2500, 3000, 3500 and 4000 m, using a systematic methodology of standard traps and pitfall lines, to inventory the shrews and rodents of the slope. Sixteen species of mammal were recorded, including 6 shrew and 10 rodent species, and the greatest diversity of both was found at 3000 m, the elevational midpoint of the transect. No species previously unrecorded on Kilimanjaro were observed. Two genera of rodents that occur in nearby mountains (Hylomyscus and Beamys) were not recorded. Myosorex zinki, the only mammal endemic to Mt. Kilimanjaro, which previously was known by only a few specimens collected in the ericaceous or moorland habitat, was found in all but one (the lowest) of the sites sampled, and was one of the most widespread species of small mammal along the gradient. Two shrews (Crocidura allex and Sylvisorex granti) and one rodent (Dendromus insignis) were found throughout the entire transect, with Dendromus being observed at our highest trap point (4240 m). As in similar faunal surveys on other mountains of Tanzania, rainfall influenced the sample success of shrews, but not rodents. Trap success for rodents at 3500 m was notably low. This study contributes further justification for the conservation of the forest habitat of Mt. Kilimanjaro.     

Prevalence of acute mountain sickness in the Swiss Alps.

OBJECTIVE--To assess the prevalence of symptoms and signs of acute mountain sickness of the Swiss Alps. DESIGN--A study using an interview and clinical examination in a representative population of mountaineers. Positive symptoms and signs were assigned scores to quantify the severity of acute mountain sickness. SETTING--Four huts in the Swiss Alps at 2850 m, 3050 m, 3650 m, and 4559 m. SUBJECTS--466 Climbers, mostly recreational: 47 at 2850 m, 128 at 3050 m, 82 at 3650, and 209 at 4559 m. RESULTS--In all, 117 of the subjects were entirely free of symptoms and clinical signs of acute mountain sickness; 191 had one or two symptoms and signs; and 158 had more than two. Those with more than two symptoms and signs were defined as suffering from acute mountain sickness. At 4559 m 11 climbers presented with high altitude pulmonary oedema or cerebral oedema, or both. Men and women were equally affected. The prevalence of acute mountain sickness correlated with altitude: it was 9% at 2850 m, 13% at 3050 m, 34% at 3650 m, and 53% at 4559 m. The most frequent symptoms and signs were insomnia, headache, peripheral oedema, and scanty pulmonary rales. Severe headache, vomiting, dizziness, tachypnoea, and pronounced pulmonary rales were associated with other symptoms and signs and therefore characteristic of acute mountain sickness. CONCLUSION--Acute mountain sickness is not an uncommon disease at moderately high altitude--that is, above 2800 m. Severe headache, vomiting, dizziness, tachypnoea, and pronounced pulmonary rales indicate severe acute mountain sickness, and subjects who suffer these should immediately descend to lower altitudes.     

Ecology of the Pteridophytes on the Southern Slopes of Mt. Kilimanjaro. Part II: Habitat Selection

Abstract: Based on the evalutation of 957 vegetation plots on the southern slope of Mt. Kilimanjaro, habitat preferences for 140 species of pteridophytes were evaluated. Using the average percentage cover value, and taking into account the pteridophyte flora's composition, life form spectra and its spectra of seasonal growth pattern, eight vegetation formations were recognized. Ferns contributed less than 1 % of the vegetation cover of salt marshes, ruderal vegetation, grasslands and (sub-)alpine heathlands. In contrast, pteridophytes constituted the most important vascular plant group on rocks, where 64 species were found, forming about two-thirds of the vegetation cover. With respect to alpha and beta diversity and fern biomass, luxuriant montane forest was the main habitat for pteridophytes on Mt. Kilimanjaro. Here 130 pteridophyte species (93 % of the whole pteridophyte flora of the study area), on average, contributed 16 % of the total vegetation cover. Epiphytic ferns, tree ferns and filmy ferns had their main distribution between 1900 and 2400 m, in a zone coinciding with the maximum rainfall on Mt. Kilimanjaro's southern slope.
Poikilohydrous species were typical of dry habitats, such as on rocks, in meadows or along roadsides, but they also occurred in the often sun-exposed epiphyte layer in moist montane forests. Deciduous species, which were in many cases fire resistant, had a similar distribution; however, inside the forest belt they were restricted to the lower and upper parts, where fires are a common phenomenon. Evergreen species were the dominant group in swamps, forests and forest clearings.
Compared to other volcanoes in East Africa, Mt. Kilimanjaro is distinctly richer in fern species in general and in filmy ferns, tree ferns and epiphytic ferns in particular, suggesting that the forest belt of the southern slope of Mt. Kilimanjaro is wetter than those of other high mountains in East Africa.     

Acetazolamide reduces exercise capacity and increases leg fatigue under hypoxic conditions.

Acetazolamide (Acz) is used at altitude to prevent acute mountain sickness, but its effect on exercise capacity under hypoxic conditions is uncertain. Nine healthy men completed this double-blind, randomized, crossover study. All subjects underwent incremental exercise to exhaustion with an inspired O(2) fraction of 0.13, hypoxic ventilatory responses, and hypercapnic ventilatory responses after Acz (500 mg twice daily for 5 doses) and placebo. Maximum power of 203 +/- 38 (SD) W on Acz was less than the placebo value of 225 +/- 40 W (P < 0.01). At peak exercise, arterialized capillary pH was lower and Po(2) higher on Acz (P < 0.01). Ventilation was 118.6 +/- 20.0 l/min at the maximal power on Acz and 102.4 +/- 20.7 l/min at the same power on placebo (P < 0.02), and Borg score for leg fatigue was increased on Acz (P < 0.02), with no difference in Borg score for dyspnea. Hypercapnic ventilatory response on Acz was greater (P < 0.02), whereas hypoxic ventilatory response was unchanged. During hypoxic exercise, Acz reduced exercise capacity associated with increased perception of leg fatigue. Despite increased ventilation, dyspnea was not increased.     

Cerebral blood flow in acute mountain sickness

Changes in cerebral blood flow (CBF) were measured using the radioactive xenon technique and were related to the development of acute mountain sickness (AMS). In 12 subjects, ascending from 150 to 3,475 m, CBF was 24% increased at 24 h [45.1 to 55.9 initial slope index (ISI) units] and 4% increased at 6 days (47.1 ISI units). Four subjects had similar increases of CBF when ascending to 3,200 m 3 mo later, indicating the reproducibility of the measurements. In nine subjects, ascending from 3,200 to 4,785-5,430 m, CBF increased to 76.4 ISI units, 53% above estimated sea-level values. CBF and increases in CBF were similar in subjects with or without AMS. In six subjects, CBF was measured before and after therapeutic intervention. At 2 h CBF increased 22% (71.3 to 87.3 ISI units) above pretreatment values in three subjects given 1.5 g acetazolamide, while three subjects given placebo showed no change. Symptoms remained unaltered in all subjects during the 2 h of the study. Overall, the results indicated that increases in CBF were similar in subjects with or without AMS while acetazolamide-provoked increases of CBF in AMS subjects caused no acute change in symptoms. Alterations in CBF cannot be directly implicated in the pathogenesis of AMS.     

Tolerance of Organ Transplant Recipients to Physical Activity during a High-Altitude Expedition: Climbing Mount Kilimanjaro

BackgroundIt is generally unknown to what extent organ transplant recipients can be physically challenged. During an expedition to Mount Kilimanjaro, the tolerance for strenuous physical activity and high-altitude of organ transplant recipients after various types of transplantation was compared to non-transplanted controls.MethodsTwelve organ transplant recipients were selected to participate (2 heart-, 2 lung-, 2 kidney-, 4 liver-, 1 allogeneic stem cell- and 1 small bowel-transplantation). Controls comprised the members of the medical team and accompanying family members (n = 14). During the climb, cardiopulmonary parameters and symptoms of acute mountain sickness were recorded twice daily. Capillary blood analyses were performed three times during the climb and once following return.ResultsEleven of the transplant participants and all controls began the final ascent from 4700 meters and reached over 5000 meters. Eight transplant participants (73%) and thirteen controls (93%) reached the summit (5895m). Cardiopulmonary parameters and altitude sickness scores demonstrated no differences between transplant participants and controls. Signs of hyperventilation were more pronounced in transplant participants and adaptation to high-altitude was less effective, which was related to a decreased renal function. This resulted in reduced metabolic compensation.ConclusionOverall, tolerance to strenuous physical activity and feasibility of a high-altitude expedition in carefully selected organ transplant recipients is comparable to non-transplanted controls.     

Contrasting patterns and drivers of soil bacterial and fungal diversity across a mountain gradient

Microbial elevational diversity patterns have been extensively studied, but their shaping mechanisms remain to be explored. Here, we examined soil bacterial and fungal diversity and community compositions across a 3.4 km elevational gradient (consists of five elevations) on Mt. Kilimanjaro located in East Africa. Bacteria and fungi had different diversity patterns across this extensive mountain gradient—bacterial diversity had a U shaped pattern while fungal diversity monotonically decreased. Random forest analysis revealed that pH (12.61% importance) was the most important factor affecting bacterial diversity, whereas mean annual temperature (9.84% importance) had the largest impact on fungal diversity, which was consistent with results obtained from mixed-effects model. Meanwhile, the diversity patterns and drivers of those diversity patterns differ among taxonomic groups (phyla/classes) within bacterial or fungal communities. Taken together, our study demonstrated that bacterial and fungal diversity and community composition responded differently to climate and edaphic properties along an extensive mountain gradient, and suggests that the elevational diversity patterns across microbial groups are determined by distinct environmental variables. These findings enhanced our understanding of the formation and maintenance of microbial diversity along elevation, as well as microbial responses to climate change in montane ecosystems.     

急性高原暴露后左心功能变化及与急性高原病的关系

目的：研究青年男性由平原急进高原后心脏血流动力学变化及其与急性高原病的关系。方法：分别检测218名健康青年男性在平原及急进高原24h内的血压、心卒和血氧饱和度,使用彩色多普勒超声仪检测左心功能;根据路易斯湖评分标准将受试者分为急性高原病纽（AMS组）和无急性高原病组（无AMS组）。结果：急性高原暴露后心率、舒张压、平均动脉压、左室射血分数、每搏输出量、每博指数、心输出量、心脏指数显著增加（P〈0．05）,血氧饱和度、左室收缩末容积则显著降低（P〈0．05）;急进高原后AMS组心率、收缩压、平均动脉压显著高于无AMS组（P〈0．05）,每博指数、左室舒张末容积显著低于无AMS组（P〈0．05）。结论：健康男性青年急性高原暴露后左心室收缩功能增强,左室舒张末容积、心率、每博指数可能作为预测急性高原病的参考指标。     

Treatment of acute mountain sickness by simulated descent: a randomised controlled trial.

OBJECTIVE--To evaluate the therapeutic efficacy of a portable hyperbaric chamber for treatment of acute mountain sickness. DESIGN--Controlled randomised trial over two mountaineering seasons. SETTING--High altitude research laboratory at 4559 m above sea level. SUBJECTS--64 climbers with acute mountain sickness randomly allocated to different treatments. INTERVENTIONS--One hour of treatment in the hyperbaric chamber at a pressure of 193 mbar or 20 mbar as control or bed rest. MAIN OUTCOME MEASURES--Symptoms of acute mountain sickness before, immediately after, and 12 hours after treatment. Permitted intake of analgesic and antiemetic drugs in the follow up period. RESULTS--Treatment with 193 mbar caused greater relief of symptoms than did control treatment or bed rest. During the 12 hour follow up period intake of analgesics was similar (58-80% of subjects in each group). Symptom scores had improved in all subjects after 12 hours with no significant differences between groups. CONCLUSIONS--One hour of treatment with 193 mbar in a portable hyperbaric chamber, corresponding to a descent of 2250 m, leads to a short term improvement in symptoms of acute mountain sickness but has no beneficial long term effects attributable to pressurisation.     

Effects of acetazolamide on aerobic exercise capacity and pulmonary hemodynamics at high altitudes.

Aerobic exercise capacity is decreased at altitude because of combined decreases in arterial oxygenation and in cardiac output. Hypoxic pulmonary vasoconstriction could limit cardiac output in hypoxia. We tested the hypothesis that acetazolamide could improve exercise capacity at altitude by an increased arterial oxygenation and an inhibition of hypoxic pulmonary vasoconstriction. Resting and exercise pulmonary artery pressure (Ppa) and flow (Q) (Doppler echocardiography) and exercise capacity (cardiopulmonary exercise test) were determined at sea level, 10 days after arrival on the Bolivian altiplano, at Huayna Potosi (4,700 m), and again after the intake of 250 mg acetazolamide vs. a placebo three times a day for 24 h. Acetazolamide and placebo were administered double-blind and in a random sequence. Altitude shifted Ppa/Q plots to higher pressures and decreased maximum O(2) consumption ((.)Vo(2max)). Acetazolamide had no effect on Ppa/Q plots but increased arterial O(2) saturation at rest from 84 +/- 5 to 90 +/- 3% (P < 0.05) and at exercise from 79 +/- 6 to 83 +/- 4% (P < 0.05), and O(2) consumption at the anaerobic threshold (V-slope method) from 21 +/- 5 to 25 +/- 5 ml.min(-1).kg(-1) (P < 0.01). However, acetazolamide did not affect (.)Vo(2max) (from 31 +/- 6 to 29 +/- 7 ml.kg(-1).min(-1)), and the maximum respiratory exchange ratio decreased from 1.2 +/- 0.06 to 1.05 +/- 0.03 (P < 0.001). We conclude that acetazolamide does not affect maximum exercise capacity or pulmonary hemodynamics at high altitudes. Associated changes in the respiratory exchange ratio may be due to altered CO(2) production kinetics.     

高原致适应剂新复方党参片预防急性高原反应的效果

目的:观察高原致适应剂新复方党参片对急性高原反应(AMS)的预防效果。方法:世居平原者驻守海拔1400m3个月的45名青年男性官兵,随机分为新复方党参片组(30人)和对照组(15人),采用单盲试验方法,于行军前5d开始分别口服新复方党参片和安慰剂片,乘车行军3d,于3700m习服4d,直至进驻高原(海拔5200m)第3天后停药,共服药15d。进驻高原后第1、3、5天,依国家军用标准GJB1098-91急性高原反应的诊断和处理原则,随访记录受试者的AMS症状,然后分度评分,检测受试者的心率(HR)、血氧饱和度(SaO2)。进驻高原后第6天,检测用力肺活量(FVC)、1秒用力呼气量(FEV1.0)、FEV1.0/FVC,一秒率(FEV1%)、最大呼气中期流速(FEF25%～75%)、呼气峰流速(PEF)、最大通气量(MVV)、左右手交叉敲击动作频率总次数(Ttis)、错误次数(Etis)、正确次数(Ctis)、平均时间(Atime)和数字记忆能力试验错误记忆次数总和(Sum)。结果:与对照组比较,进驻高原后第1、3、5d,新复方党参片组AMS症状显著减轻(P0.01);新复方党参片组与对照组的AMS程度分度分布不同(P0.01),新复方党参片组中症状较轻的(基本无反应、轻度反应)占比重较大,而对照组中症状较重的(中度反应、重度反应)占比重较大;新复方党参片组AMS发生率明显降低;与对照组比较,新复方党参片组的FVC、FEV1.0、FEF25%～75%、PEF、MVV升高有统计学意义(P0.05,P0.01),FEV1%差异无统计学意义;与对照组比较,新复方党参片组的Ttis、Ctis增加(P0.05,P0.01),Atime减少(P0.05),Etis和Sum差异无统计学意义。结论:新复方党参片能减轻AMS的程度,减轻AMS的症状,降低AMS发生率;并能显著改善受试者的肺通气功能和手指运动能力。     

Dispersal and speciation of East African mountain bushcrickets of the genus Phlesirtes (Orthoptera: Tettigoniidae: Conocephalinae,Conocephalini) related to climate fluctuations

A phylogeny of the genus Phlesirtes Bolivar is presented, based on new sequence data of three genes (16S rDNA, COI, H3). Species of the genus Phlesirtes (subtribe Karniellina of the Tribe Conocephalini) occupy habitats of montane to afroalpine grasslands in East Africa. Phlesirtes is the most species‐rich genus of the subtribe Karniellina, a group of small flightless Ensifera restricted to eastern Africa. Taken together, the biogeographical patterns seen in Phlesirtes and its molecular phylogeny suggest a migration scenario: the mountain ranges acting as stepping stones, enabling a spread of Phlesirtes ancestors during periods of favourable climatic conditions in the past. The Pleistocene inland volcanoes, such as Mt Kenya or Mt Kilimanjaro, allow us to date speciation processes within the genus Phlesirtes. It is suggested that cooler humid periods of the past 3 Ma boosted speciation of Phlesirtes in East Africa.