Hexamoll DINCH plasticised PVC containers for the storage of platelets.

INTRODUCTION: Containers for the storage of platelets are made using polyvinyl chloride plasticised with di, (2-ethyl hexyl) phthalate, n-butyryl, tri (n-hexyl) citrate and tri (2-ethyl hexyl) mellitate or using special poly olefins without plasticiser. Of these, the first two have disadvantages such as plasticiser leaching and impairment of platelet function. Polyolefin bags cannot be HF welded or steam sterilized. Mellitate plasticised bags can store platelets well for five days but they are not completely phthalate free. RESEARCH AND DEVELOPMENT: We have developed a new generation of containers made of PVC plasticised with the non DEHP, non aromatic plasticiser,1,2- Cyclohexanedicarboxylic acid, diisononyl ester (Hexamoll DINCH) which can store platelets without loss of function for at least six days. OBSERVATION: The present studies show that DINCH plasticised PVC bags (TPL-167) are well suited for the storage of platelet concentrates for more than five days. CONCLUSION: The present studies show that the PVC plasticised with the non phthalate, non aromatic, non toxic plasticiser DINCH is a viable alternative to other existing containers for the storage of platelets for more than five days.

Thyroid function during a prolonged stay in Antarctica.

Adaptation of the thyroid gland to the Antarctic environment was studied in nine healthy euthyroid tropical men of the Sixth Indian Antarctic Expedition during 1 year of their residence at polar latitudes. Circulatory concentrations of thyroid hormones, total T4 (TT4), total T3 (TT3), free T4 (FT4), free T3 (FT3), reverse T3 (rT3), thyroxine binding globulin (TBG), T3 uptake and thyroid stimulating hormone (TSH) were estimated in New Delhi and during the first week of each month of the stay in Antarctica. At the end of the Austral summer in March, the TT3 concentrations were found to be significantly lower (P < 0.01) compared to values recorded in New Delhi and showed a significant increase (P < 0.05) during the Austral winter in August. The mean TT3 concentrations from May to December were found to be significantly higher than the March or April values. Plasma TT4 and rT3 concentrations tended to decline in March but remained unaltered during the entire period in Antarctica. The FT4, FT3, TBG and T3 uptake did not show any appreciable change. Though, the TT3:TT4 ratio tended to decline in March and April suggesting decreased peripheral conversion of T4 to T3 as the possible mechanism for a decline in TT3 in March. physical exertion and prolonged exposure to extreme cold appeared to be the major contributory factors. The TSH concentration in March, April, November and December were found to be significantly higher than the New Delhi values. The morning as well as evening cortisol concentrations during the Austral winter were higher than the March values suggesting that cortisol rhythmicity was well maintained in Antarctica, albeit at a higher level. These observations indicated that the subtle changes in thyroid hormones during a prolonged stay at polar latitudes are related not only to the extreme cold but also to other factors such as physical activity, polar days and polar nights.

Effect of post-hypoxic acclimatization on extremity temperature during exposure to acute cold stress in man.

Twelve male volunteers aged 20-28 yr, who were physically fit for high altitude duties were studied. Recordings of oral temperature, mean skin temperature, extremity temperature, O2 consumption and heart rate were taken in a thermoneutral room (26 degrees +/- 2 degrees C) and cold room (6 degrees-8 degrees C) initially; after 4 wk stay at 3353 m (502 mm Hg); again after 4 wk at 4115 m (455 mm Hg); and finally after return to Delhi (740 mm Hg). The oral temperature, mean skin temperature, oxygen consumption and heart rate did not show any significant difference from their initial sea level values recorded in the thermoneutral room or the cold room. It may be concluded that our subjects did not exhibit any degree cold acclimatization when retested at sea level. A significant elevation (P less than 0.001) of extremity temperature observed during retest in cold might be due to some degree of vasodilatation through relaxation of constrictor tone that might have taken place during exposure to hypoxia at high altitude.

Studies on heat output from the hand of frostbite subjects.

We studied 12 subjects, who had suffered first- to third-degree frostbite at high altitude during winter, at Delhi, India. At normal sea level pressure there (PB 740 mm Hg) and in a decompression chamber at a simulated altitude of 4085 m, the studies were at both 26 degrees C and 6.8 degrees C. A group of control (non-frostbite) subjects of comparable age were also studied for their heat output at 26 degrees C, PB 740 mm Hg. Heat output from the hands of a group of mountaineers from the sea level was also studied at 2121 m at 25 degrees C and 4485 m at 7 degrees C. The results indicated that the frostbite subjects had a significantly higher heat ouput at PB 740 mm Hg and 26 degrees C than the non-frostbite subjects. When the former were tested at sea level (PB 740 mm Hg) at 6.8 degrees C, the hand heat output showed a marked and significant decrease. On testing them at a simulated altitude of 4085 m at 26 degrees C and at 6.8 degrees C, a very highly significant reduction in hand heat output was observed compared to their initial value at sea level (740 mm Hg) and 26 degrees C. Their hand heat output also showed a very highly significant decrease compared to mountaineers at 4485 m and 7 degrees C.