Spironolactone and acute mountain sickness

Thirteen adults trekking in Nepal in 1974 to altitudes between 4,300 m and 5,500 m remained free from acute mountain sickness while taking spironolactone as a prophylactic measure. Two years previously five of these adults trekking at similar altitudes, but without treatment, had suffered from acute mountain sickness. The regime used was spironolactone in a dosage of 25 mg three times a day for two days preceding and during the periods spent at altitudes above 3,000 m.     

Pulmonary gas exchange in acute mountain sickness

The severity of acute mountain sickness (AMS) was investigated in healthy volunteers, airlifted to high altitude (5,360 m). Blood gases were measured at 2,990 m and 5,360 m. Symptoms of AMS were found in all subjects, but ranged from malaise to vomiting with intractable headache. The clinical severity of AMS was directly related to the arterial PCO2 and inversely to pH, but unrelated to the PO2 on arrival at high altitude. However, PO2 fell and was lowest 48 h after arrival at high altitude in those subjects with the most severe AMS. These were the only subjects to show an increase in the alveolar-arterial PO2 difference and in the venous admixture ratio during the first 48 h. These abnormalities in gas exchange, which developed in the subjects with the most marked cerebral symptoms, suggest that the manifestations of cerebral and pulmonary dysfunction at altitude develop simultaneously, a finding that suggests coexisting cerebral and pulmonary edema.     

Endothelial selectins in acute mountain sickness and high-altitude pulmonary edema

STUDY OBJECTIVES: Mechanical or inflammatory injury to pulmonary endothelial cells may cause impaired pulmonary gas exchange in acute mountain sickness (AMS) and noncardiogenic pulmonary edema in high-altitude pulmonary edema (HAPE). This study was designed to determine whether markers of endothelial cell activation or injury, plasma E- and P-selectin, were increased after ascent to high altitude, in AMS or in HAPE. DESIGN: We collected clinical data and plasma specimens in control subjects at sea level and after ascent to 4,200 m, and in climbers with AMS or HAPE at 4,200 m. Data analysis was performed using standard nonparametric statistical methods, and results reported as mean+/-SD. SETTING: National Park Service medical camp at 4,200 m on Mt. McKinley (Denali), Alaska. PATIENTS: Blood samples and clinical data were collected from 17 healthy climbers at sea level and again after ascent to 4,200 m, and from a different group of 13 climbers with AMS and 8 climbers with HAPE at 4,200 m. Climbers with AMS were divided into normoxic (n=7) and hypoxemic (n=6) groups. MEASUREMENTS AND RESULTS: Using an enzyme immunoassay technique, plasma E-selectin concentrations were found to be increased in the 17 control subjects after ascent to 4,200 m (17.2+/-8.2 ng/mL) as compared to sea level (12.9+/-8.2 ng/mL) (p=0.001). Plasma E-selectin concentrations were also increased in subjects with hypoxemic AMS (30.6+/-13.4 ng/mL) and HAPE (23.3+/-9.1 ng/mL) compared to control subjects at sea level (p=0.009). Increased plasma E-selectin concentration significantly correlated with hypoxemia (p=0.006). Plasma P-selectin concentrations were unchanged after ascent to 4,200 m and in subjects with AMS and HAPE. CONCLUSION: Because E-selectin is produced only by endothelial cells, increased plasma E-selectin after ascent to high altitude and in hypoxemic climbers with AMS and HAPE provides evidence that endothelial cell activation or injury is a component of hypoxic altitude illness.     

Assessment of acute mountain sickness by different score protocols in the Swiss Alps

INTRODUCTION: Purpose of the present study was to evaluate the Lake Louise acute mountain sickness (AMS) score questionnaire at different altitudes and to compare it with the currently used clinical score and the environmental symptoms questionnaire AMS-C score. METHODS: We investigated 490 climbers who stayed over night at 4 huts in the Swiss Alps, located at the altitudes of 2850 m, 3050 m, 3650 m, and 4559 m. AMS was assessed using our previously described clinical score, the Lake Louise consensus AMS score questionnaire and the environmental symptoms questionnaire III. RESULTS: Below 4000 m, the prevalence of AMS, defined by symptoms that force a reduction in activity, was 7%; when assessed with the clinical score (score > or = 3) it was 22%; with the AMS-C score (score > or = 0.7) 4% and with the Lake Louise score (score > 4) 8%. At the altitude of 4559 m, the prevalence of AMS was 30%, 38%, 40%, and 39%, respectively. The standardized regression coefficients from multiple regression analysis (adjusted R2 0.65, p < 0.001) were 0.45 (p < 0.001) for the self-reported Lake Louise score, 0.48 (p < 0.001) for the sum of the points assigned in the clinical section of the Lake Louise questionnaire, and 0.05 (p = 0.27) for the AMS-C score. The sensitivity and specificity of the Lake Louise score > 4 was 78% and 93%, respectively. CONCLUSIONS: The Lake Louise consensus score is adequate and, compared with the AMS-C score, more effective for the assessment of acute altitude illness at different altitudes.     

Evaluation of the Lake Louise acute mountain sickness scoring system in a hypobaric chamber

This study evaluated the relevance of the Lake Louise acute mountain sickness (AMS) scoring system in comparison with other AMS scoring systems. To achieve this objective nine subjects were submitted to a 9-hr exposure to hypoxia in a hypobaric chamber (altitude 4500-5500 m) that led to the development of AMS. AMS was scored at the end of this exposure period both by questionnaires (Hackett AMS questionnaire, Lake Louise AMS self-report questionnaire, Environmental Symptoms Questionnaire ESQ II and ESQ IV) and by a clinical investigation following the Lake Louise AMS clinical and functional AMS assessment. The AMS scores were between 0 and 9 for the Hackett AMS score, 0 and 38 for the ESQ II AMS score, 0 and 13.7 for the ESQ IV AMS score, 0 and 10 for the Lake Louise AMS self-report, 0 and 2 for the Lake Louise AMS clinical assessment score, and between 0 and 2 for the Lake Louise functional score. All the AMS questionnaire scores were related to the clinical AMS assessment score (p < 0.05) without significant differences between them. The Lake Louise AMS self-report score appeared highly correlated to other AMS scoring systems (Hackett, ESQ II and ESQ IV) (p < 0.05). Suggestions were proposed to improve the sensitivity and the specificity of the Lake Louise AMS scoring questionnaire but also the Lake Louise AMS clinical assessment. In conclusion, this study suggests the relevance of the Lake Louise AMS self-report questionnaire to assess and score AMS with simplicity and rapidity.     

Pathophysiological effects of hemodilution in chronic mountain sickness in rats

We examined the effect of isovolemic hemodilution in a rat model of chronic mountain sickness (CMS). After 30 days at simulated high altitude (5,500 m), Hilltop rats had developed evidence of CMS: severe hypoxemia, polycythemia, and pulmonary arterial hypertension. Isovolemic hemodilution to a mean hematocrit of 46 +/- 5% was well tolerated by both the hypoxia-sensitive Hilltop rats and the companion Madison rat strain that does not develop CMS. After hemodilution, we found no evidence of sustained improvements in ventilation or gas exchange in either strain. Despite the fall in blood viscosity, cardiac output increased only marginally, and pulmonary arterial hypertension persisted in the Hilltop rats. Vascular hindrance increased after hemodilution, preventing a significant decline in pulmonary and systemic vascular resistances in the Hilltop rats. Blood O2 content and the coefficient of O2 delivery fell after hemodilution, but O2 consumption was sustained at a normal level after hemodilution by increasing the extraction fraction in the Hilltop strain. There was systemic hypotension through the first day of hemodilution, but this was the only apparent adverse effect of hemodilution. We conclude that isovolemic hemodilution was well tolerated despite the reduction in tissue O2 delivery. However, hemodilution failed to improve any of the respiratory and cardiovascular manifestations of CMS in Hilltop rats.     

Quantitative EEG in subcortical neglect

We have analyzed the regulatory roles of the first intron (intron-1) of the bovine beta-casein gene in the bovine beta-casein/CAT expression system using a mouse mammary epithelial cell line, HC11. After a combined treatment of HC11 cells with insulin, dexamethasone and prolactin, the induced expression of p beta c1.8/+ICAT vector including 2 kb intron-1 and 1.8 kb promoter was greatly increased to 23.5 folds, while that of p beta ca.8CAT basic vector with 1.8 kb promoter only, was 6.5. A classical enhancer activity was shown in the 2 kb intron fragment from the experiment in which the orientation and the position of the intron-1 on the vectors were changed. The enhancer activity was largely dependent on the lactogenic hormones, especially prolactin. A stepwise reduction of the inducibility in the 5' to 3' deletion analysis of the intron-1 indicates the existence of several functional elements in the region. In particular, an internal fragment (+1071 to +1490) was important for the prolactin-dependent enhancing activity of the intron-1. These results suggest that several elements in the intron-1 of the bovine beta-casein gene cooperatively interact not only with each other but also with its promoter for hormonal induction.     

Acute mountain sickness in the Southern Alps of New Zealand

AIM: To assess the incidence and impact of acute mountain sickness in the Southern Alps of New Zealand. METHODS: Over a 22 month period, mountaineers in the Mount Cook region were asked to complete a questionnaire at the completion of their climbing excursions. The questionnaire recorded demographic data and incorporated the Lake Louise scoring system to assess the presence of acute mountain sickness. RESULTS: Of the 114 subjects who completed the questionnaire, 30 (26%) developed acute mountain sickness. The incidence was higher amongst those who slept above 2500 m (50%). Of those with acute mountain sickness, 33% reported that their symptoms resulted in no reduction in activity, while 13% reported a moderate or severe reduction in activity. CONCLUSION: Mountaineers climbing in New Zealand's Southern Alps should be aware of the risk of acute mountain sickness, especially for those sleeping above 2500 m.     

Quantitative EEG in assessment of anesthesia depth. Methods of comparison

Methodology for assessment of depth of anaesthesia based on analysis of the electroencephalogram (eeg) is controversial. Techniques range from display of single measures, for example median value of the frequency spectrum, to dedicated pattern recognition systems based on measures of several eeg features. We have compared the performance of four techniques using tape-recorded data from 23 patients anaesthetised with either halothane or isoflurane using standardised regimens. The techniques were: median frequency, spectral edge frequency, the cerebral function analysing monitor (CFAM-1) and a depth of anaesthesia monitor based on eeg pattern recognition (ADAM). Dose-response curves are presented for stepwise increases in stable end-tidal concentrations of each agent. Results indicated considerable inter-patient variability and showed the limitations of single eeg measures, particularly with deeper anaesthesia producing burst suppression patterns in the eeg. Pattern recognition techniques reduced these difficulties and appeared to be promising over a wide range of anaesthetic levels.     

Cytokines in the aspect of pathogenesis and therapy of acute radiation sickness

The statement about dominating role of stem cell failure (exhaustion) in acute radiation bone marrow syndrome outcome needs to be changed. Cytokine-producing cells lacking reactivity that prevent usage of stem cell compartment reserves can play important role in immunohemopoiesis radiation damage.     

EEG coherence following acute and chronic clozapine in treatment-resistant schizophrenics.

Electroencephalographic (EEG) coherence is an index of brain regional coupling that has been found to be abnormal in people with schizophrenia but has not been systematically examined in response to neuroleptics. EEG coherence in slow (delta and theta) frequencies was assessed in 17 treatment-resistant people with schizophrenia at baseline, 2 hr after their first oral dose (25 mg) and after 6 weeks of clozapine treatment. Compared with EEG norms, participants exhibited significant interhemispheric and intrahemispheric coherence abnormalities prior to treatment. Both acute and chronic treatments altered coherence but differed with respect to their relationship to symptom reduction and their ability to normalize or augment pretreatment abnormalities. Findings are discussed in relation to "disconnection" theories of schizophrenia. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Quantitative patterns in the clinical manifestations of radiation sickness in large laboratory animals exposed to radiation at superlethal doses. The quantitative patterns in the manifestations of radiation sickness in dogs

Radiation sickness manifestations have been studied in dogs exposed to electrons (electron energy 25 MeV) and gamma-neutron radiation (neutron energies of 0.37 and 1.2 MeV) in a wide dose range. Dose-response relationships have been calculated for mortality and some clinical manifestations of the intestinal and cerebral forms of radiation sickness. With regard to mortality, the highest effect has been observed for gamma-neutron radiation with a neutron energy of 1.2 MeV. For equal physical doses and for those equally effective in relation to mortality, clinical manifestations of damage are more prominent following exposure to electrons.     

Health status of persons with acute radiation sickness caused by Chernobyl AES accident

Chemical prophylaxis is known to reduce the venographic prevalence of deep-vein thrombosis (DVT) after total knee replacement (TKR), but it is uncertain whether this affects the incidence of symptoms. Further analysis depends on the basic epidemiology of thromboembolic symptoms. We therefore studied the pattern of such symptoms in a consecutive series of 1000 patients with primary TKR, with particular reference to risk factors and prophylaxis. We reviewed all the clinical records and contacted all the patients individually, noting risk factors, prophylaxis, symptomatic pulmonary embolus (PE) or DVT and its timing, death and its causes, and all complications. All the patients wore antiembolism stockings, 83% had regional anaesthesia and 33.9% had chemical prophylaxis. One patient died from PE on the day of surgery, having had no prophylaxis giving a rate of 0.1% (95% CI 0.003% to 0.56%). Symptomatic, radiologically confirmed thromboembolism (VTE) was common with a rate of 10.6% (95% CI 8.7% to 12.5%). There was a similar incidence of VTE in those with and without chemical prophylaxis (10.1% v 10.5%, RR 0.96, NS). VTE was more common in patients with risk factors (15.1% v 9.5%, RR 1.59, p = 0.02) and tended to occur earlier in this group (median day of onset 5 v 7, p = 0.01). Chemical prophylaxis did not reduce the frequency of symptomatic thromboembolism in either those with risk factors (RR 0.81, p = 0.5) or those without them (RR 0.94, p = 0.8). Haematoma or wound dehiscence was more common in those having chemical prophylaxis (11.9% v 6.9%; RR 1.73 95% CI 1.16 to 2.60). Readmission for symptomatic, radio-logically confirmed thromboembolism involved 1.1% of patients (95% CI 0.55% to 2.1%). Four patients were readmitted with proven non-fatal PE and six with proven DVT (the latest on day 40). Our results show that the main risk factor for thromboembolism was TKR itself; chemical prophylaxis did not reduce the incidence of symptomatic thromboembolism but gave an increased perception of side-effects. New prophylactic methods or combinations of methods are needed, with their efficacy compared by randomised controlled studies of both the clinical and the radiological effect.     

Decompression sickness in Ireland--a review

In the last decade there has been an increase in the incidence of decompression sickness in Ireland. The modern diver, equipped with specially developed diving equipment, is exposed to abnormal physiological conditions. This has resulted in a spectrum of medical conditions, which need to be recognised, diagnosed and treated. The department of Underwater Medicine at University College Hospital, Galway, is the only referral centre in the Republic of Ireland for patients suffering from decompression sickness. Early recognition and referral for treatment dramatically improves patient outcome. A one year's review of patients referred for treatment is presented.     

In sickness and in health

Inhibition of the polymerase chain reaction (PCR) by components of the analyzed specimen is an important problem in analysis of clinical material by this method. The inhibitory activity of clinical material can be decreased by additional purification of DNA by gel filtration on microcolumns. The method was developed using blood-containing specimens and tried on many clinical specimens. Commercial PCR kit for detecting Mycobacterium tuberculosis was used. The proposed method for DNA purification notably improves the efficacy of detecting the agents by PCR.