- Email: [email protected]
CRYOPRECIPITATE PREPARATION
165
given in injections of 25 ml, and the accepted by the patients.
doses
resides in the neutrophils. This is further supported by the inability of control normal sera to restore adequate phagocytic function to the patient’s normal cells. She exhibits no other tendency to recurrent infections. It would be of interest to ascertain whether other patients with anaerobic breast abscess exhibit similar impairment of phagocyte function. Departments of Pathology and Surgery, Newcastle General
Plasma Protein Research Department, Nordisk Insulinlaboratorium, DK-2820 Gentofte, Denmark
H. R. INGHAM R. FREEMAN R. G. WILSON
Hospital,
Newcastle upon Tyne NE4 6BE
SIR,-We wish to support Dr Pines’ plea that sedatives should not be given at altitude. Arterial desaturation at altitude is usually increased during sleep owing to diminished ventilation and periodic breathing.2 The resultant decrease in tissue oxygenation may potentiate altitude oederna.3 Much of the insomnia at high altitude is a manifestation of acute mountain sickness; acetazolamide, which increases alveolar ventilation, prevents the arterial oxygen saturation during sleep2 and also reduces the severity of acute mountain sickness.4 In contrast, diazepam and, probably, other sedatives blunt the hypoxic ventilatory responses and would be expected to aggravate sleep hypoxaEmia when given to numb the physical discomforts of cold, cramped quarters of mountain camps. We believe that acetazolamide improves sleep at altitude, possibly by improving oxygenation during sleep, whereas sedatives may worsen sleep oxygenation and potentiate cerebral and pulmonary oedema.
D.C.I.E.M., Toronto, Ontario
GARY W. GRAY
Department of Community Medicine, University of Vermont, Burlington, Vermont, U.S.A.
CHARLES S. HOUSTON
M. EZBAN J. F. HANSEN
SIR,-Field et al.l2 have described a test for multiple sclerosis (M.S.) based on alteration of the electrophoretic mobility of erythrocytes by unsaturated fatty acids, the E-UFA test. The crux of the test seems to be the change reported with linoleic acid (L.A.). In the’ presence of 80 p.glml L.A. the electro, phoretic mobility of cells from normal donors and patients with other neurological diseases (O.N.D.) was in all cases significantly faster than without L.A., whereas in all M.S. cases the cell mobility was significantly slowed. Stoof et awl. and Forrester and Smith4 have been unable to repeat these results. A reports supporting Field’s claim provides no statistical analysis and no details of the absolute mobilities found. We have looked at a series of 8 healthy volunteers, 16 M.S. patients, and 24 O.N.D. All were on normal diets without polyunsaturated fatty acid supplements. Numbered samples were taken by different individuals. The code was left sealed until the series was complete. All glassware was bought new. No detergents were used in cleaning. All measurements were carried out with a Zeiss cytopherometer in Gibco ’Biocult’
CEREBRAL ŒDEMA
JOHN R. SUTTON A. C. PETER POWLES
is well
ERYTHROCYTE ELECTROPHORETIC MOBILITY TEST FOR MULTIPLE SCLEROSIS
INSOMNIA, SEDATION, AND HIGH ALTITUDE
Department of Medicine, McMaster University, Hamilton, Ontario, Canada
treatment
1. 2. 3.
Field, E. J., Joyce, G. Lancet, 1976, ii, 367. Field, E. J., Joyce, G., Smith, B. M. J. Neurol. 1977, 214, 113. Stoof, J. C., Vrijmoed-De Vries, M. C., Koetsier, J. C., Langevoort, H. L., Acta neurol. scand. 1977, 56, 170. 4. Forrester, J. A., Smith, W. J. Lancet, 1977, ii, 453. 5. Bisaccia, G., Caputo, D., Zibetti, A. Boll. Ist. Sieroter. milan. 1977, 56, 583.
CRYOPRECIPITATE PREPARATION
SIR,-We fully agree that fast-thaw methods improve the factor-vm yield in cryoprecipitate, but our experience with the use of electromagnetic radiation for thawing plasma differs from that of Dr Crawford and colleagues.6 We have been able to thaw frozen plasma by using microwaves in such a way that the temperature- does not rise anywhere above 4°C. Thawing from -20°C takes about 5 min. We could accomplish this by using lower power and higher frequency than those referred to by Crawford et al. In our procedure the frequency is 2.4GHz with a power output of
1 kW/!plasma. Our microwave-thawing procedure has now been applied in our production of small-pool freeze-dried cryoprecipitate for nearly a year. In addition to a good yield of factor vin (about 500 units/! plasma), we obtain a product with a remarkably high solubility (20 U/ml). In haemophiliacs 100% in-vivo recovery and a long half-life were obtained. This factor-vm product has been used mainly for home treatment in 500 unit <
1. Pines, A. Lancet,
1978, ii, 938. 2. Sutton, J. R., Hackett, P., Houston, C. S., Mansell, A., McFadden, M., Menkis, A., Powles, A. C. P. Clin. Res. 1977, 25, 714A. 3. Sutton, J. R., Lassen, N. Bull. Eur. Physiopathol. Resp. (in the press). 4. Gray, G. W., Bryan, A. C., Frayser, R. Houston, C. S., Rennie, I. D. Aerospace Med. 1971, 42, 81. 5. Lakshminarayan, S., Sahn, S. A., Hudson, L. D., Weil, J. V. Clin. Pharmac. 6.
Ther. 1976, 20, 1978. Crawford, R. J., Barr, A., Mitchell,
R. Lancet,
1978, ii, 844.
on electrophoretic mobility of adding linoleic erythrocytes from normal volunteers, M.S. patients, tients with other neurological diseases.
Effect
acid to and pa-
given in injections of 25 ml, and the accepted by the patients.
doses
resides in the neutrophils. This is further supported by the inability of control normal sera to restore adequate phagocytic function to the patient’s normal cells. She exhibits no other tendency to recurrent infections. It would be of interest to ascertain whether other patients with anaerobic breast abscess exhibit similar impairment of phagocyte function. Departments of Pathology and Surgery, Newcastle General
Plasma Protein Research Department, Nordisk Insulinlaboratorium, DK-2820 Gentofte, Denmark
H. R. INGHAM R. FREEMAN R. G. WILSON
Hospital,
Newcastle upon Tyne NE4 6BE
SIR,-We wish to support Dr Pines’ plea that sedatives should not be given at altitude. Arterial desaturation at altitude is usually increased during sleep owing to diminished ventilation and periodic breathing.2 The resultant decrease in tissue oxygenation may potentiate altitude oederna.3 Much of the insomnia at high altitude is a manifestation of acute mountain sickness; acetazolamide, which increases alveolar ventilation, prevents the arterial oxygen saturation during sleep2 and also reduces the severity of acute mountain sickness.4 In contrast, diazepam and, probably, other sedatives blunt the hypoxic ventilatory responses and would be expected to aggravate sleep hypoxaEmia when given to numb the physical discomforts of cold, cramped quarters of mountain camps. We believe that acetazolamide improves sleep at altitude, possibly by improving oxygenation during sleep, whereas sedatives may worsen sleep oxygenation and potentiate cerebral and pulmonary oedema.
D.C.I.E.M., Toronto, Ontario
GARY W. GRAY
Department of Community Medicine, University of Vermont, Burlington, Vermont, U.S.A.
CHARLES S. HOUSTON
M. EZBAN J. F. HANSEN
SIR,-Field et al.l2 have described a test for multiple sclerosis (M.S.) based on alteration of the electrophoretic mobility of erythrocytes by unsaturated fatty acids, the E-UFA test. The crux of the test seems to be the change reported with linoleic acid (L.A.). In the’ presence of 80 p.glml L.A. the electro, phoretic mobility of cells from normal donors and patients with other neurological diseases (O.N.D.) was in all cases significantly faster than without L.A., whereas in all M.S. cases the cell mobility was significantly slowed. Stoof et awl. and Forrester and Smith4 have been unable to repeat these results. A reports supporting Field’s claim provides no statistical analysis and no details of the absolute mobilities found. We have looked at a series of 8 healthy volunteers, 16 M.S. patients, and 24 O.N.D. All were on normal diets without polyunsaturated fatty acid supplements. Numbered samples were taken by different individuals. The code was left sealed until the series was complete. All glassware was bought new. No detergents were used in cleaning. All measurements were carried out with a Zeiss cytopherometer in Gibco ’Biocult’
CEREBRAL ŒDEMA
JOHN R. SUTTON A. C. PETER POWLES
is well
ERYTHROCYTE ELECTROPHORETIC MOBILITY TEST FOR MULTIPLE SCLEROSIS
INSOMNIA, SEDATION, AND HIGH ALTITUDE
Department of Medicine, McMaster University, Hamilton, Ontario, Canada
treatment
1. 2. 3.
Field, E. J., Joyce, G. Lancet, 1976, ii, 367. Field, E. J., Joyce, G., Smith, B. M. J. Neurol. 1977, 214, 113. Stoof, J. C., Vrijmoed-De Vries, M. C., Koetsier, J. C., Langevoort, H. L., Acta neurol. scand. 1977, 56, 170. 4. Forrester, J. A., Smith, W. J. Lancet, 1977, ii, 453. 5. Bisaccia, G., Caputo, D., Zibetti, A. Boll. Ist. Sieroter. milan. 1977, 56, 583.
CRYOPRECIPITATE PREPARATION
SIR,-We fully agree that fast-thaw methods improve the factor-vm yield in cryoprecipitate, but our experience with the use of electromagnetic radiation for thawing plasma differs from that of Dr Crawford and colleagues.6 We have been able to thaw frozen plasma by using microwaves in such a way that the temperature- does not rise anywhere above 4°C. Thawing from -20°C takes about 5 min. We could accomplish this by using lower power and higher frequency than those referred to by Crawford et al. In our procedure the frequency is 2.4GHz with a power output of
1 kW/!plasma. Our microwave-thawing procedure has now been applied in our production of small-pool freeze-dried cryoprecipitate for nearly a year. In addition to a good yield of factor vin (about 500 units/! plasma), we obtain a product with a remarkably high solubility (20 U/ml). In haemophiliacs 100% in-vivo recovery and a long half-life were obtained. This factor-vm product has been used mainly for home treatment in 500 unit <
1. Pines, A. Lancet,
1978, ii, 938. 2. Sutton, J. R., Hackett, P., Houston, C. S., Mansell, A., McFadden, M., Menkis, A., Powles, A. C. P. Clin. Res. 1977, 25, 714A. 3. Sutton, J. R., Lassen, N. Bull. Eur. Physiopathol. Resp. (in the press). 4. Gray, G. W., Bryan, A. C., Frayser, R. Houston, C. S., Rennie, I. D. Aerospace Med. 1971, 42, 81. 5. Lakshminarayan, S., Sahn, S. A., Hudson, L. D., Weil, J. V. Clin. Pharmac. 6.
Ther. 1976, 20, 1978. Crawford, R. J., Barr, A., Mitchell,
R. Lancet,
1978, ii, 844.
on electrophoretic mobility of adding linoleic erythrocytes from normal volunteers, M.S. patients, tients with other neurological diseases.
Effect
acid to and pa-