Fate of chemicals in plant-soil systems: comparison of laboratory test data with results of open air long-term experiments

Three laboratory short-term test systems were used to determine volatilization rates, mineralization rates, and conversion rates of 14 14C-labeled chemicals in soils or soil-plant systems. The chemicals covered a wide range of water solubility, vapor pressure, chemical stability, and biodegradability. In order to compare the data obtained with the environmental behavior of the respective chemicals, data from an outdoor experimental setup which had been shown to give residue data within the range limits of field conditions were used. Volatilization rates, mineralization rates, and conversion rates obtained in the laboratory were correlated to those found under outdoor conditions. Based on these correlations, predictions of field residues were made. The predicted values for total field residues were comparable to those found experimentally with the exception of two chemicals. The prediction of residues of unchanged parent compounds in the field was less satisfactory. The reasons for differences observed are discussed.

Effect of furosemide on altitude tolerance in experimental animals

Furosemide which is claimed to prevent acute mountain sickness and pulmonary oedema of high altitude was tried in experimental animals to evaluate its usefulness or otherwise as a measure of prophylaxis. 90 mice, 128 rats and 44 guinea pigs--all males--were used for the studies. Half the number in each species were kept as controls. The remaining half were further divided into two batches. The first batch was given furosemide 10 mg/kg body weight. Two h later they were exposed to simulated altitude of 30,000 ft for 6 h. The second batch was given two injections of furosemide at intervals of 24 h before exposure to simulated altitude. The controls were given distilled water. Our results show that the death rate was more in the furosemide-treated groups, both under mild as well as severe dehydration in all species. The present study does not substantiate the claim than the drug can be used as prophylactic against acute mountain sickness and pulmonary oedema of high altitude.

Effect of hypoxia on regional lung perfusion, by scanning

Lung scanning was performed in 12 subjects who had pulmonary oedema of high altitude (POHA) before, and in 8 men who had been at high altitude without developing pulmonary oedema. Scanning done before and after 5 min 10% O2 breathing showed (a) increased perfusion in POHA subjects after hypoxia, (b) more in the lower than in upper zones, and (c) striking increase in perfusion in localised areas. In controls, however, there was significant reduction in perfusion after hypoxia in most areas. The reduction was less marked in the lower zones than in the upper zones. POHA subjects were hyperreactors to hypoxia, compared to controls. It is concluded that scanning before and after hypoxic breathing might help in differentiating hyperreactors.

Technique for bonding gold and silver metals on sapphire

A technique is described for bonding gold and silver metals onto sapphire. This technique has been successfully used in ac calorimetry for heat capacity of films.

Allergic bronchopulmonary aspergillosis

Allergic bronchopulmonary aspergillosis (ABPA) is not a common condition, even though asthma due to sensitization to Aspergillus antigen is very common in many countries because of the ubiquitous distribution of the fungus itself. During the course of 14 years, the Mycology Department of the V. P. Chest Institute, Delhi, has confirmed the diagnosis of ABPA in 46 patients. The present study is based on the follow-up of 17 patients for understanding the evolution of the disease. All of them had Aspergillus fumigatus (AF) in the sputum with positive type I and type III skin reaction to AF antigen. 7 patients were treated for 10 days with oral administration of Hamycin, an antibiotic isolated from one of the streptomycete species. Immediate results were very good, with marked alleviation of subjective symptoms and absence of fungi in the sputum. The drug deserves further trial.

Further studies on pulmonary oedema of high altitude. Abnormal responses to hypoxia of men who had developed pulmonary oedema at high altitude

101 Indian soldiers, 57 of whom had developed pulmonary oedema of high altitude (POHA) and 44 who had not developed this condition in spite of being at high altitudes for over 2 years, were investigated for observing the differences, if any, in their reaction to acute hypoxic stress. Each subject was made to breathe a 10% hypoxic mixture for 5 min. Haemodynamic parameters like pulmonary artery pressure (systolic, diastolic and mean), brachial artery pressure, wedge pressure, cardiac output, minute ventilation, arterial oxygen saturation and oxygen uptake before and at the end of hypoxic breathing were estimated. In addition, results of the cold pressor test were recorded and the Vd/Vt ratio was estimated. The results obtained in the present study confirmed those obtained in our previous studies. In addition, it was observed that oxygen uptake was significantly higher and oxygen saturation lower after hypoxia in the POHA subjects than in the controls. Certain parameters for screening of subjects possibly susceptible to POHA have been suggested.

Effect of acute hypobaric hypoxia on fatty acid metabolism in rat lung

Exposure of male albino rats in the weight range of 70-200 g to 25,000 ft of simulated altitude for 6 h at 32 degrees C caused an increase in plasma free fatty acids with decreased oxidation of palmitic acid-1-14C in lung slices of hypoxic rats. The in vivo esterification of palmitic acid-1-14C to form truglycerides, phosphatidylcholine and phosphatidylethanolamine was also low indicating decreased utilization of fatty acids by hypoxic lungs. De novo lipogenesis was observed to decreased to decrease because of decreased fatty acid biosynthesis as judged from acetate---14C incorporation. The specific activities of triglycerides, phosphatidylcholine and free cholesterol were also decreased. The decreased incorporation into phosphatidylcholine affected the incorporation into phosphatidylcholine of alveolar surfactant (2,000 g sediment fraction). The results are discussed in view of possible decreased energy status of hypoxic lungs.

Fatty acid metabolism in hypoxic rat liver

Fatty acid metabolism was investigated in adult male albino rats exposed to hypobaric hypoxia at 25,000 ft simulated altitude for 6 h at 32 degrees C. Oxidation and esterification of palmitic acid-1-14C and de novo lipogenesis from acetate-1-14C were studied. Palmitic acid-1-14C oxidation in liver slices was normal while acetoacetate formation was increased. In vivo esterification of palmitic acid-1-14C to form triglycerides was increased while formation of phosphatidylcholine and phosphatidylethanolamine was observed to decrease. Decreased incorporation into plasma phosphatidylcholine with unaltered total activity in plasma triglycerides was observed. The incorporation of acetate-1-14C was observed to remain unaltered in triglycerides and phospholipids of liver with a similar pattern in the plasma indicating unaltered de novo lipogenesis. There appears to be increased esterification of fatty acids with probably impaired release of triglycerides into plasma while fatty acid biosynthesis remains unaffected.