Regional differences in the cerebral blood flow velocity response to hypobaric hypoxia at high altitudes.

Symptoms of acute mountain sickness (AMS) may appear above 2,500 m altitude, if the time allowed for acclimatization is insufficient. As the mechanisms underlying brain adaptation to the hypobaric hypoxic environment are not fully understood, a prospective study was performed investigating neurophysiological changes by means of near infrared spectroscopy, electroencephalograpy (EEG), and transcranial doppler sonography at 100, 3,440 and 5,050 m above sea level in the Khumbu Himal, Nepal. Fourteen of the 26 mountaineers reaching 5,050 m altitude developed symptoms of AMS between 3,440 and 5,050 m altitude (Lake-Louise Score ⩾3).

Mild functional ischemic mitral regurgitation following acute coronary syndrome: a retrospective study.

Background: Ischemic mitral regurgitation is a frequent complication of acute coronary syndrome. It primarily occurs in patients with a prior myocardial infarction but also may be seen with acute ischemia, a setting in which the MR typically resolves after the ischemia resolves. The vast majority of patients have "functional" ischemic MR.

Middle cerebral artery preponderance in ischemic stroke: a coincidence or fate?

Stroke is the leading cause of disability and the third leading cause of death in the United States. More than 700,000 persons per year suffer a first-time stroke in the United States, with 20% of these individuals dying within the first year after the stroke. Ischemic stroke accounts for majority of cases of stroke and within this subgroup also, anterior circulation stroke involving the middle cerebral artery (MCA) is the commonest one.

Post percutaneous coronary intervention antiplatelet therapy: current perceptions, prospects and perplexity.

Dual antiplatelet therapy (DAT) has become standard care for patients undergoing percutaneous coronary intervention (PCI). Following balloon injury and stent placement, the intima at the site is distressed, resulting in the activation of coagulation cascade and platelets. In the case of bare metal stents (BMS), it takes six to eight weeks for the stent surface to be covered with neointima.

Hypertension in the elderly: Are we all on the same wavelength?

Hypertension is of frequent occurrence in the elderly population. Isolated systolic hypertension (ISH) accounts for the majority of cases of hypertension in the elderly. ISH is associated with a 2-4-fold increase in the risk of myocardial infarction, left ventricular hypertrophy, renal dysfunction, stroke, and cardiovascular mortality.

Acute mountain sickness in children at 4380 meters in the Himalayas.

Objective: To determine the incidence of and risk factors for acute mountain sickness (AMS) in native Nepalese children during a pilgrimage trip to Gosaikunda Lake in the Langtang National Park Region of Nepal (elevation 4380 m).

Methods: A descriptive, noninterventional, cross-sectional study was completed on a group of children during the pilgrimage to Gosaikunda. Participants were interviewed about the symptoms of AMS using the Lake Louise Scoring System.

Two hypoxia sensor genes and their association with symptoms of acute mountain sickness in Sherpas.

Introduction: Hypoxia-inducible factor (HIF) and von Hippel-Lindau tumor suppressor protein (VHL) are hypoxia sensors that control cellular responses to hypoxia. Although many Sherpas live at high altitudes for their entire lives, some of them manifest symptoms of acute mountain sickness (AMS) during mountaineering at extremely high altitudes. We hypothesize that the two hypoxia sensor genes might associate with the occurrence of AMS symptoms in Sherpas at extremely high altitude.

Adaptation to high altitude in Sherpas: association with the insertion/deletion polymorphism in the Angiotensin-converting enzyme gene.

Objective: Sherpas are well-known for their physical strength at high altitudes. They adapt to high altitude so well that little acute or chronic mountain sickness has been documented in them. The possible genetic basis for this adaptation is, however, unclear.

Right temporal cerebral dysfunction heralds symptoms of acute mountain sickness.

Acute mountain sickness (AMS) can occur during climbs to high altitudes and may seriously disturb the behavioral and intellectual capacities of susceptible subjects. During a Himalayan expedition 32 mountaineers were examined with electroencephalography (EEG) and transcranial doppler sonography (TCD) to assess relative changes of middle cerebral artery velocity in relation to end-expiratory CO2 (EtCO2), peripheral saturation (SaO2), and symptoms of AMS. We tested the hypothesis that O2 desaturation and EtCO2 changes precede the development of AMS and result in brain dysfunction and compensatory mechanisms which can be measured by EEG and TCD, respectively.

Symptoms of acute mountain sickness in Sherpas exposed to extremely high altitude.

Droma, Yunden, Masayuki Hanaoka, Buddha Basnyat, Amit Arjyal, Pritam Neupane, Anil Pandit, Dependra Sharma, and Keishi Kubo. Symptoms of acute mountain sickness in Sherpas exposed to extremely high altitude. High Alt.

Genetic contribution of the endothelial nitric oxide synthase gene to high altitude adaptation in sherpas.

The Sherpas' adaptation to high altitude has been hypothesized as being due to a genetic basis since the beginning of the last century, but this has yet to be demonstrated. We randomly enrolled 105 Sherpas in Namche Bazaar (3440 m) and 111 non-Sherpa Nepalis in Kathmandu (1330 m) in Nepal. The genotypes of Glu298Asp and eNOS4b/a polymorphisms of the endothelial nitric oxide synthase (eNOS) gene were identified.

Increase in 6-hydroxymelatonin excretion in humans during ascent to high altitudes.

Melatonin (MLT), the pineal gland hormone involved in the regulation of circadian rhythms, shows characteristic diurnal variation. Its physiological role in humans is not clear. Exposure to high altitudes may disrupt the circadian rhythm and lead to various endocrine changes.