Please select the eligibility criteria that correspond to the clinical trial below.
Title: Randomized Double-Blind Placebo-Controlled Trial of Oral Anti-Oxidant Supplementation for the Prevention of Acute Mountain Sickness.
Brief Summary: Acute mountain sickness (AMS), high altitude pulmonary edema (HAPE), and high altitude cerebral edema (HACE) are complications of rapid ascent to high altitude. Several features suggest that raised intracranial pressure (ICP) may be an important factor in the pathogenesis of AMS. Magnetic resonance imaging of HACE patients has demonstrated that the oedema in HACE is of the vasogenic, rather that cytotoxic, type. Thus it is likely that cerebrovascular permeability has an important role in the development of AMS and HACE.

Reactive oxygen species (ROS) have been shown to alter the permeability of the blood-brain barrier in severe ischaemia, causing vasogenic cerebral oedema. Endogenous antioxidant systems may have some capacity to respond to oxidative stress in hypoxia. The plasma concentration of urate, a powerful endogenous antioxidant, rises on acute exposure to high altitude and may play a crucial antioxidant role in systemic hypoxia. This antioxidant prevents free-radical induced cerebral oedema in animal models.

There are numerous sources of ROS in hypoxia, including the mitochondrial electron transfer chain, haemoglobin (Hb) autoxidation and xanthine oxidase activity. There have been several reports of raised markers of oxidative stress in humans at moderate altitude (\<3000m).

Oral antioxidant supplementation with preparations containing vitamins C and E in humans at altitude has been shown to decrease breath pentanes (a marker of oxidative stress), and improve erythrocyte filterability. In a small randomised controlled trial, Bailey and Davies demonstrated a significant reduction in symptoms of AMS in subjects taking an oral antioxidant cocktail.

The antioxidants alpha-lipoic acid, vitamin C and vitamin E act synergistically to provide membrane protection from free radical damage, and may protect against hypoxia-induced vascular leakage. We hypothesised that this combination of antioxidants would reduce the severity of acute mountain sickness, and reduce pulmonary artery pressures, in healthy lowlanders acutely exposed to high altitude.


Options:
A: Inclusion Criteria:

* age between 20 and 55 years.
* able to complete the study protocol of 9-day study regimens and mountain climbing twice.
* no prophylactic medication or herb one month before ascent.
* maintaining the same living conditions and habits four months before the first mountain climbing and four months between two mountaineering.

  * living in the same altitude or within a difference of 200 meters.
  * no additional physical training.
  * no plan to gain or loss weight.
  * no altitude exposure above 2500m.

Exclusion Criteria:

* any history of chronic obstructive pulmonary disease, heart failure, cerebral neoplasm, mania, renal or hepatic insufficiency.
* women in pregnancy or intending of pregnancy during the 4-month study period.
B: Inclusion Criteria:

* Participants in Apex 2 trial

Exclusion Criteria:

* High altitude pulmonary oedema (HAPE)
* Gasto-intestinal illness
C: Inclusion Criteria:

* Chronic obstructive pulmonary disease (COPD), GOLD grade 1-2
* Living at low altitude (\<800m)

Exclusion Criteria:

* COPD exacerbation
* severe COPD, GOLD grade 3 or 4
* arterial oxygen saturation \<92% at low altitude (\<800 m)
* Diabetes, uncontrolled cardiovascular disease such as systemic arterial hypertension, coronary artery disease; previous stroke; pneumothorax in the last 2 months, untreated or symptomatic peptic ulcer disease, glaucoma, obstructive sleep apnea.
* Internal, neurologic or psychiatric disease that interfere with protocol compliance including current heavy smoking (\>20 cigarettes per day).
* pregnant or nursing patients
D: Inclusion Criteria:

1. Age 18-65 healthy non-pregnant volunteer
2. Sea-level dwelling (live at low elevation \< 4000 ft)
3. Arrange your own transportation to WMRS (Bishop) by Friday evening of study weekend
4. Available for full study duration (Friday PM-Sunday AM)

Exclusion Criteria:

1. Age \<18 or \>65, Pregnant, Live at altitude \>4000 ft
2. Slept at altitude \> 4000ft within 1 week of study
3. Allergic to acetazolamide, sulfa drugs, or non-steroidal anti-inflammatories
4. Taking NSAIDs, Acetazolamide, or Corticosteroids 1 week prior to study
5. Medical History of Brain Tumor, increased brain pressure, pseudotumor cerebri, VP shunts, HACE, or HAPE.

Answer: B