New treatment strategies for malignant gliomas

Malignant gliomas are the most prevalent type of primary brain tumor in adults. Despite progress in brain tumor therapy, the prognosis of malignant glioma patients remains dismal. The median survival of patients with glioblastoma muhiforme, the most common grade of malignant glioma, is 10-12 months. Conventional therapy of surgery, radiation and chemotherapy is largely palliative. Essentially, tumor recurrence is inevitable. Salvage treatments upon recurrence are palliative at best and rarely provide significant survival benefit. Therapies targeting the underlying molecular pathogenesis of brain tumors are urgently required. Common genetic abnormalities in malignant glioma specimens are associated with aberrant activation or suppression of cellular signal transduction pathways and resistance to radiation and chemotherapy.     

Ambulatory blood pressure monitoring

Ambulatory blood pressure monitoring (ABPM) in adults is proving to be useful. The aim of this study was to determine if ABPM is accurate in the lower blood pressure range encountered in children and, equally important, whether it is acceptable to children. Thirty one children, between the ages of 6 and 18 years, were assessed using an ambulatory blood pressure monitor that uses an auscultatory method. Blood pressure was measured in the contralateral arm with a mercury sphygmomanometer and an oscillometric device at the beginning and end of the study for comparison. Over a blood pressure range of 90-130 mm Hg systolic and 40-80 mm Hg diastolic, a close agreement was found with the sphygmomanometer; the limits of agreement (+/- 2 SD) were 11.6 mm Hg for systolic blood pressure and 13.6 mm Hg for diastolic blood pressure. The bias was less than 1.0 mm Hg. The ambulatory device was worn by all patients for at least 16 hours with an average of 52 recordings per patient. The majority found the device comfortable to wear and were not woken from sleep.     

Lung function in military oxygen divers: a longitudinal study

It is increasingly recognized that professional diving may elicit adverse long-term effects on the lungs, but conflicting results have been reported from distinct diving cohorts. This study reports the longitudinal change in lung function in professional divers who employ closed-circuit oxygen rebreathing apparatuses. All oxygen divers who attended the German Naval Medical Institute between 1994 and 1999 for regular medicals underwent spirometry and were entered if they had at least two follow-up examinations. Forced expiratory flows and volumes at baseline and at maximum follow up were compared. There were 39 divers who presented at least 3 times during a median period of 5.8 (2.7-8) yr. Forced expiratory volume in 1 s (FEV1) and forced vital capacity (FVC) amounted to 4.86 +/- 0.62 L and 5.89 +/- 0.67 L at baseline, and 4.83 +/- 0.64 L and 5.87 +/- 0.69 L at maximum follow up, respectively. The change over time was statistically not significant. Substantial exposure to elevated oxygen partial pressure while diving is not associated with an accelerated decline in lung function. Factors other than hyperoxia (e.g., venous gas microemboli and altered breathing gas characteristics) may account for the long-term effects that have been found in professional divers.     

Efficacy of acupressure and acustimulation bands for the prevention of motion sickness

INTRODUCTION: The purpose of this study was to examine whether acupressure and acustimulation prevent motion sickness, taking into consideration whether or not the acupressure and acustimulation are administered properly. These techniques claim to reduce nausea through stimulation of the P6/Neiguan acupuncture point by applying acupressure or electrical acustimulation. METHODS: The Acuband and ReliefBand were used to administer acupressure and acustimulation, respectively. There were 77 subjects who were assigned to 1 of 5 conditions: Acuband trained or untrained; ReliefBand trained or untrained; or placebo. Subjects were exposed to a 20-min baseline and a maximum of 20 min of optokinetic drum rotation. Untrained subjects read the device directions, used it as they deemed appropriate, and completed a usability analysis following drum exposure. Trained subjects read the device directions and were trained to use the device appropriately prior to drum exposure. Symptoms and gastric myoelectric activity were monitored during baseline and rotation. RESULTS: In all conditions, symptoms of motion sickness and gastric tachyarrhythmia increased, and 3 cpm gastric myoelectric activity decreased, during drum exposure. The only difference found between conditions was a potential delay in symptom onset for the ReliefBand compared with the Acuband. While the Acuband was found difficult to use (0 untrained subjects used it correctly) and only a few minor usability issues were identified for the ReliefBand, usability had no impact on efficacy. DISCUSSION: Neither band nor placebo prevented the development of motion sickness, regardless of whether the bands were used correctly or incorrectly.     

Protein-predominant meals inhibit the development of gastric tachyarrhythmia, nausea and the symptoms of motion sickness

BACKGROUND: Meal ingestion has been suggested to reduce susceptibility to the development of gastric tachyarrhythmia, the abnormal activity of the stomach that frequently accompanies nausea. AIM: To determine the types of meal that are most effective in preventing the development of gastric tachyarrhythmia, nausea and the symptoms of motion sickness provoked by a rotating optokinetic drum. METHOD: Participants received a carbohydrate beverage, a protein-predominant beverage or nothing immediately before exposure to the rotating drum. Subjective symptoms of motion sickness and electrogastrograms were collected during a 6-min baseline period and a subsequent 16-min drum rotation period. RESULTS: Subjective symptoms of motion sickness scores were significantly more severe during the no-meal condition than during either the protein or carbohydrate condition. Central, peripheral and, to some extent, gastrointestinal symptoms were more severe during the carbohydrate condition than during the protein condition. Gastric tachyarrhythmia increased significantly less from baseline to drum rotation during both the protein and carbohydrate conditions than during the no-meal condition. CONCLUSIONS: Liquid protein-predominant meals were most effective in suppressing both the development of gastric tachyarrhythmia and the entire spectrum of motion sickness symptoms, including nausea.     

Arterial blood gases during diving in elite apnea divers

Elite apnea divers have considerably extended the limits of dive depth and duration but the mechanisms allowing humans to tolerate the compression- and decompression-induced changes in alveolar gas partial pressures are still not fully understood. Therefore we measured arterial blood gas tensions and acid-base-status in two elite apnea divers during simulated wet dives lasting 3 : 55 and 5 : 05 minutes, respectively. Arterial pO2 followed the compression-(from 13.8/16.9 kPa before the dive to 30 kPa at the start of the bottom time) and decompression-induced (from 13.7/21.0 kPa to 3.3/4.9 kPa immediately after surfacing) variations of ambient pressure, while the arterial pCO2 remained within the physiologic range (3.0/3.9 kPa before diving vs. 5.7/5.9 kPa at the end of the bottom time), probably due to the CO2 storage capacity of the blood. These findings may help to explain why humans can sustain deep and long apnea dives without major increases in respiratory drive.     

Using flight simulators aboard ships: human side effects of an optimal scenario with smooth seas

INTRODUCTION: The U.S. Navy is considering placing flight simulators aboard ships. It is known that certain types of flight simulators can elicit motion adaptation syndrome (MAS), and also that certain types of ship motion can cause MAS. The goal of this study was to determine if using a flight simulator during ship motion would cause MAS, even when the simulator stimulus and the ship motion were both very mild. METHODS: All participants in this study completed three conditions. Condition 1 (Sim) entailed "flying" a personal computer-based flight simulator situated on land. Condition 2 (Ship) involved riding aboard a U.S. Navy Yard Patrol boat. Condition 3 (ShipSim) entailed "flying" a personal computer-based flight simulator while riding aboard a Yard Patrol boat. Before and after each condition, participants' balance and dynamic visual acuity were assessed. After each condition, participants filled out the Nausea Profile and the Simulator Sickness Questionnaire. RESULTS: Following exposure to a flight simulator aboard a ship, participants reported negligible symptoms of nausea and simulator sickness. However, participants exhibited a decrease in dynamic visual acuity after exposure to the flight simulator aboard ship (T[25] = 3.61, p < 0.05). Balance results were confounded by significant learning and, therefore, not interpretable. DISCUSSION: This study suggests that flight simulators can be used aboard ship. As a minimal safety precaution, these simulators should be used according to current safety practices for land-based simulators. Optimally, these simulators should be designed to minimize MAS, located near the ship's center of rotation and used when ship motion is not provocative.