First result from the Alpha Magnetic Spectrometer on the International Space Station: precision measurement of the positron fraction in primary cosmic rays of 0.5-350 GeV.

A precision measurement by the Alpha Magnetic Spectrometer on the International Space Station of the positron fraction in primary cosmic rays in the energy range from 0.5 to 350 GeV based on 6.8 × 10(6) positron and electron events is presented. The very accurate data show that the positron fraction is steadily increasing from 10 to ∼ 250 GeV, but, from 20 to 250 GeV, the slope decreases by an order of magnitude. The positron fraction spectrum shows no fine structure, and the positron to electron ratio shows no observable anisotropy. Together, these features show the existence of new physical phenomena.

Celecoxib, a highly selective COX-2 inhibitor, is safe in aspirin-induced asthma patients.

BACKGROUND: In 5-10% of adult patients with asthma, aspirin and most other nonsteroidal anti-inflammatory drugs (NSAIDs) precipitate acute asthmatic attacks. Therefore, choosing an alternative anti-inflammatory agent for patients who have suffered adverse reactions to a nonsteroidal anti-inflammatory agent is a common problem in clinical practice. The discoveries that cyclooxygenase COX-2 is an inducible form of COX involved in inflammation and COX-1 is the major isoform responsible for the production of prostaglandins have provided a reasonable basis for the development of specific COX-2 inhibitors as a new class of anti-inflammatory agents. OBJECTIVE: The purpose of this study is to demonstrate that celecoxib, a specific inhibitor of COX-2, does not cause asthmatic attacks in patients with aspirin and/or other nonsteroidal anti-inflammatory drug-induced asthma. METHODS: We studied 33 patients, all of whom suffered from asthma induced by at least two different NSAID drugs. They were challenged in a single-blind manner with different doses of celecoxib on three different days, until either the therapeutic dose of 200 mg or intolerance was reached. Each patient was rechallenged with 200 mg celecoxib seven days later if no evidence of intolerance was previously observed. RESULTS: Celecoxib 200 mg was proven to be well tolerated in all 30 three aspirin- and NSAID-induced asthma patients. CONCLUSION: Our study appears to demonstrate that celecoxib is a suitable NSAID in aspirin-induced and/or nonsteroidal anti-inflammatory drug-induced asthma patients.

A comparison of the effects of the inhalation of 4% and 8% fluroxene in the pregnant primate.

A comparison was made of the effects of inhalation of 4% fluroxene (n = 5) and 8% fluroxene (n = 5) in pregnant monkeys. Measurements of maternal arterial blood pressure, heart rate, cardiac output, total peripheral resistance, uterine blood flow, fetal heart rate and arterial blood pressure, and maternal and fetal blood gas levels were made. Inhalation of 4% fluroxene for 20 minutes produced little change in maternal hemodynamics and was well tolerated by the fetus. Fluroxene 8% inhaled for a similar 20-minute-period produced a significant decrease in maternal blood pressure (--27%), total peripheral resistance (--32%), and uterine blood flow (--27%) and lowered the level of maternal fetal exchange.

[Nitrates in canned spinach. Effects of technological treatments]. / Les nitrates dans les épinards en conserve. Influence des traitements technologiques.

During the last twenty years, the nitrate content of spinach has regularly increased along with the use of nitragenous fertilizers. A study made in the center of Britain (France) shows that along with this growing nitrate content, the quantity of raw harvested spinach has practically doubled in twenty years. But for the same quantity of raw harvested spinach, the yield of canned spinach has noticeably lowered. In a cannery trials made to lower the nitrate levels (preheating, blanching, renewing water blanching) led to a loss of about 45% of nitrate (on a dry matter basis). However nitrate levels stay about the same in one kg of raw spinach and in one kg of processed spinach coming from the same batch. The only answer seems to be able and come from better agricultural practices.

Respiratory depression in newborn monkeys at Caesarean section following ketamine administration.

Ketamine, currently being evaluated as an obstetric anaesthetic agent, is said to provide analgesia without depression of the protective airway reflexes or depression of the respiratory or cardiovascular systems. We have studied the effects of ketamine on the uterine blood flow, the foetus and the newborn in five monkeys (Macaca nemistrina). Uterine blood flow, (UBF) was measured by the steady-state infusion technique using tritiated water as the indicator. All of the variables were measured during a control period and again at 10 and 90 min after the administration of ketamine in doses of 2 mg/kg in three monkeys or 1 mg/kg in two. Maternal respiration was maintained at normal physiological levels without significant variation. The maternal mean arterial pressure (MAP), cardiac output (CO), and stroke volume (SV) did not change significantly, but heart rate (HR) did increase significantly following the injection of ketamine and remained increased for the duration of the study. UBF, a-v oxygen difference, and the oxygen consumption of the uterus and its contents remained stable throughout. During the intrauterine period the foetus did not seem to be affected by the two doses of ketamine. However, the three newborn monkeys delivered of the mothers who had reveived ketamine 2 mg/kg had profound respiratory depression. This was not seen in the two infants delivered from mothers receiving 1 mg/kg. Others have shown that neonatal depression is dose- and time-related. We conclude that ketamine should be administered to obstetric patients in small single doses or by continuous infusion in very low concentrations.

Effects of peridural block: V. Properties, circulatory effects, and blood levels of etidocaine and lidocaine.

Ten healthy, unpremedicated, male volunteers, aged 21-33 years, were given 20 ml 1 per cent etidocaine with 5 mug/ml epinephrine for peridural analgesia via a catheter placed L2. On a different occasion they were given 20 ml 2 per cent lidocaine with 5 mug/ml epinephrine in the same manner. Initial onset of sensory analgesia to pin prick was faster for etidocaine (7 min) than for lidocaine (9 min). Analgesia lasted significantly longer after etidocaine with respect to both two-segment regression (177 plus or minus SE min vs. 114 plus or minus 8 min) and total duration (379 plus or minus 22 min vs. 190 plus or minus 8 min). Onset of maximal motor blockade was significantly faster with etidocaine (15.4 plus or minus 2.5 min) than with lidocaine (31.7 plus or minus 3.3 min); blockade lasted longer with etidocaine (331 plus or minus 25 min vs. 167 plus or minus 13 min). Changes in mean arterial pressure cardiac output, central venous pressure, limb blood flows, total peripheral resistance, and stroke volume were similar with the two drugs, although those after etidocaine were more prolonged as a result of the longer blockade. Mean maximum arterial concentrations of etidocaine were 0.96 plus or minus 0.05 SE mug/ml (plasma) and 0.55 plus or minus 0.03 mug/ml (whold blood), achieved at 17 plus or minus 2 min. Mean maximum arterial concentrations of lidocaine were 2.22 plus or minus 0.09 mug/ml (plasma) and 1.85 plus or minus mug/ml (whold blood), achieved at 24 plus or minus 2 min. No sign of central toxicity was observed with either drug, although subjects receiving lidocaine tended to sleep, which was not the case with etidocaine. Hematologic screening, blood chemistries, and urinalyses performed 24 hours before and after each study showed no abnormality.

Maternal and fetal responses to halothane in pregnant monkeys.

Maternal cardiac output, blood pressure, heart rate, fetal blood pressure, heart rate and respiratory blood gases, and uterine blood flow were measured in six pregnant monkeys during halothane-nitrous oxide and oxygen anesthesia and compared to theses same parameters observed during nitrous oxide and oxygen anesthesia. Halothane 1.5% was associated with a decrease in maternal arterial pressure (54%), heart rate (10%), cardiac output (17%), total peripheral resistance (40%), and uterine blood flow (38%). Mean fetal heart rate decreased 18% and mean fetal blood pressure 22%. These changes in fetal hemodynamics were probably related to a direct depression of the fetal cardiovascular system and its usual compensatory mechanism as well as the fetal asphyxia secondary to the decrease in uterine blood flow.