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PHOTODYNAMIC THERAPY OF TUMOURS
209 Umin., to cover
one
contraction in mid-labour. The
mem-
branes were intact.
To avoid confusing the photographs a minimum of lettering has been added. In B, the space of the fetal trunk in this transverse scan is marked F, and P is regarded as an expanded placental sinus lying, as it does, between irregular
surfaces of placental tissue. Some of these spaces may be outside the placental cotyledons and contain amniotic fluid moved to higher levels (the patient was supine) by the force of the contraction. In C, at the height of the contraction in square 2,1, from the intersection of axes, the fetal thigh, with its central bone, is clearly seen as a circle with a well-defined edge, in the amniotic fluid. The placental spaces are above this. One is in the lower part of square 2,3. The scale of the pictures is 3 cm. per grid division. Fetal parts are not seen, for the placenta is most clearly delineated at low sensitivity. Scans are made rapidly with two sweeps of the probe and minimum oscillation of probe direction from the " radial " direction. A longitudinal scan is made first to ascertain the position of maximum placental thickness. This example was made 3 cm. above the umbilicus. These observations are relevant also to the mechanics of the fetal circulation in labour. If pressure differences occur between the placental maternal sinuses and the fetal amniotic-fluid compartment there will be a transfer of fetal blood-volume between the fetus and the fetal villi in the placenta and corresponding changes in the peripheral resistance of the fetal circulation. While the fetus remains physiologically normal it corrects its heart-rate toward the maintenance of constant blood-pressure. These considerations should weigh in the assessment of fetal distress when there is a bradycardia or tachycardia in sympathy with the uterine contractility. After the membranes are ruptured, or when amniotic fluid is sparse, it may not be correct to regard the pressure in the amniotic fluid as the pertinent parameter of force on the fetus or on the placental circulation. This study was made in the Allamanna Barnbordshuset Hospital, Stockholm, under the direction of Docent Lennart Lindgren with a Picker Ultrasonic scanner kindly loaned by Mr H. Gauffin of Scanfoss AB.
University College Hospital Medical School, Department of Obstetrics and Gynæcology,
C. N. SMYTH.
London WC1E 6DH.
to have a photosensitising action dependent on oxygen,3 it is not true to say that haematoporphyrin is a photodynamic agent. It is a photosensitising agent with a photodynamic action. This point is made to encourage future workers to be more specific in the use of photobiological terms. The authors mention that light penetrates the intact skull into the brain of large and small animals. The actual amount of penetration through the intact skull and meninges must be very small. Indeed, in normal human skin, only about 10% of irradiation of 400 nm. wavelength penetrates to a depth of 2-8 mm. Though there is some evidence for long-wave ultraviolet irradiation penetrating into the brain,4 the brain and spinal cord are usually screened not only by the physical thickness of the skin and hair but also by the skin pigment and additional pigment cells in the meningeal layers surrounding them.5 Though satisfactory evidence seems to have been put forward by Diamond et al. that the photodynamic therapy of malignant tumours might be a possibility, it seems extremely unlikely that sufficient light energy would penetrate the intact skull to be of actual clinical value in treatment. Centre Hospitalier Universitaire, Sherbrooke, Quebec, Canada.
PETER S. HERMAN.
FUNCTIONAL IMPROVEMENT WITH LONG-TERM LEVODOPA THERAPY
SIR,-18 patients with Parkinson’s disease treated with
levodopa were regularly assessed by standard tasks. Ages ranged from 54 to 76 years (average 66), and the disease had been present for from 2 to 13 years (average 7-25). Levodopa was given in doses ranging from 0-75 g. to 3-0 g. a day (average 1-9 g.). Four standard tests were analysed over an average of 21 months: (a) time to walk 132 feet with three turns; (b) number of 8-inch steps climbed in 30 seconds; (c) and (d) number of handgrips performed in 30 seconds with right and left hands, respectively. These results were statistically evaluated using the paired t test, comparisons being made between pre-dopa and the results after three to five months of treatment (each value usually being an average of three assessments). All comparisons showed a statistical improvement, or no change, the probability of improvement occurring by chance being as follows:
PHOTODYNAMIC THERAPY OF TUMOURS SIR,-Iwas very interested in the preliminary communication by Diamond et al.1 Certainly, the suggestion that
photodynamic therapy
may be
approach to the resistant to existing neoplasms treatment is fascinating. It is mentioned that porphyrins are powerful photodynamic agents which can sensitise biological preparations so that they are severely damaged when exposed to visible or near-ultraviolet light. Since its introduction, the term photodynamic action has been little understood and much abused,2 because of nonadherence to the strict definition, particularly in regard to the obligate role of oxygen. Most workers use the term freely to imply a dynamic action-that is, one that is distinct and readily discernible. The term is now generally replaced by the all-encompassing and less specific word " photosensitisation ". Though hasmatoporphyrin has been shown a
new
management of human
1. 2.
Diamond, I., Granelli, S. G., McDonagh, A. F., Nielsen, S., Wilson, C. B., Jaenicke, R. Lancet, 1972, ii, 1175. Herman, P. S., Sams, W. M., Jr. in Soap Photodermatitis: Photosensitivity to Halogenated Salicylanilides; p. 12. Springfield, Illinois, 1972.
As anticipated there was a statistically significant improvement between pre-dopa and both the 3-5 months and the latest assessments, varying between 0-1% and 1% values. When the 3-5 months assessment was compared with the latest figures, while there was no significant change in walking or climbing, there was a significant improvement at the 5% level in hand function. This is a very satisfactory result with levodopa with concurrent anticholinergic therapy in a group of Parkinson’s patients who were not entirely typical, being in a special clinic because of the early development of dyskinesia, nausea, 3. McGrae, J. D., Perry, H. O. Archs Derm. 4. Menaker, M. Sci. Am. 1972, 226, 22. 5. Steven, D. M. Biol. Rev. 1963, 38, 204.
1963, 87, 252.
one
contraction in mid-labour. The
mem-
branes were intact.
To avoid confusing the photographs a minimum of lettering has been added. In B, the space of the fetal trunk in this transverse scan is marked F, and P is regarded as an expanded placental sinus lying, as it does, between irregular
surfaces of placental tissue. Some of these spaces may be outside the placental cotyledons and contain amniotic fluid moved to higher levels (the patient was supine) by the force of the contraction. In C, at the height of the contraction in square 2,1, from the intersection of axes, the fetal thigh, with its central bone, is clearly seen as a circle with a well-defined edge, in the amniotic fluid. The placental spaces are above this. One is in the lower part of square 2,3. The scale of the pictures is 3 cm. per grid division. Fetal parts are not seen, for the placenta is most clearly delineated at low sensitivity. Scans are made rapidly with two sweeps of the probe and minimum oscillation of probe direction from the " radial " direction. A longitudinal scan is made first to ascertain the position of maximum placental thickness. This example was made 3 cm. above the umbilicus. These observations are relevant also to the mechanics of the fetal circulation in labour. If pressure differences occur between the placental maternal sinuses and the fetal amniotic-fluid compartment there will be a transfer of fetal blood-volume between the fetus and the fetal villi in the placenta and corresponding changes in the peripheral resistance of the fetal circulation. While the fetus remains physiologically normal it corrects its heart-rate toward the maintenance of constant blood-pressure. These considerations should weigh in the assessment of fetal distress when there is a bradycardia or tachycardia in sympathy with the uterine contractility. After the membranes are ruptured, or when amniotic fluid is sparse, it may not be correct to regard the pressure in the amniotic fluid as the pertinent parameter of force on the fetus or on the placental circulation. This study was made in the Allamanna Barnbordshuset Hospital, Stockholm, under the direction of Docent Lennart Lindgren with a Picker Ultrasonic scanner kindly loaned by Mr H. Gauffin of Scanfoss AB.
University College Hospital Medical School, Department of Obstetrics and Gynæcology,
C. N. SMYTH.
London WC1E 6DH.
to have a photosensitising action dependent on oxygen,3 it is not true to say that haematoporphyrin is a photodynamic agent. It is a photosensitising agent with a photodynamic action. This point is made to encourage future workers to be more specific in the use of photobiological terms. The authors mention that light penetrates the intact skull into the brain of large and small animals. The actual amount of penetration through the intact skull and meninges must be very small. Indeed, in normal human skin, only about 10% of irradiation of 400 nm. wavelength penetrates to a depth of 2-8 mm. Though there is some evidence for long-wave ultraviolet irradiation penetrating into the brain,4 the brain and spinal cord are usually screened not only by the physical thickness of the skin and hair but also by the skin pigment and additional pigment cells in the meningeal layers surrounding them.5 Though satisfactory evidence seems to have been put forward by Diamond et al. that the photodynamic therapy of malignant tumours might be a possibility, it seems extremely unlikely that sufficient light energy would penetrate the intact skull to be of actual clinical value in treatment. Centre Hospitalier Universitaire, Sherbrooke, Quebec, Canada.
PETER S. HERMAN.
FUNCTIONAL IMPROVEMENT WITH LONG-TERM LEVODOPA THERAPY
SIR,-18 patients with Parkinson’s disease treated with
levodopa were regularly assessed by standard tasks. Ages ranged from 54 to 76 years (average 66), and the disease had been present for from 2 to 13 years (average 7-25). Levodopa was given in doses ranging from 0-75 g. to 3-0 g. a day (average 1-9 g.). Four standard tests were analysed over an average of 21 months: (a) time to walk 132 feet with three turns; (b) number of 8-inch steps climbed in 30 seconds; (c) and (d) number of handgrips performed in 30 seconds with right and left hands, respectively. These results were statistically evaluated using the paired t test, comparisons being made between pre-dopa and the results after three to five months of treatment (each value usually being an average of three assessments). All comparisons showed a statistical improvement, or no change, the probability of improvement occurring by chance being as follows:
PHOTODYNAMIC THERAPY OF TUMOURS SIR,-Iwas very interested in the preliminary communication by Diamond et al.1 Certainly, the suggestion that
photodynamic therapy
may be
approach to the resistant to existing neoplasms treatment is fascinating. It is mentioned that porphyrins are powerful photodynamic agents which can sensitise biological preparations so that they are severely damaged when exposed to visible or near-ultraviolet light. Since its introduction, the term photodynamic action has been little understood and much abused,2 because of nonadherence to the strict definition, particularly in regard to the obligate role of oxygen. Most workers use the term freely to imply a dynamic action-that is, one that is distinct and readily discernible. The term is now generally replaced by the all-encompassing and less specific word " photosensitisation ". Though hasmatoporphyrin has been shown a
new
management of human
1. 2.
Diamond, I., Granelli, S. G., McDonagh, A. F., Nielsen, S., Wilson, C. B., Jaenicke, R. Lancet, 1972, ii, 1175. Herman, P. S., Sams, W. M., Jr. in Soap Photodermatitis: Photosensitivity to Halogenated Salicylanilides; p. 12. Springfield, Illinois, 1972.
As anticipated there was a statistically significant improvement between pre-dopa and both the 3-5 months and the latest assessments, varying between 0-1% and 1% values. When the 3-5 months assessment was compared with the latest figures, while there was no significant change in walking or climbing, there was a significant improvement at the 5% level in hand function. This is a very satisfactory result with levodopa with concurrent anticholinergic therapy in a group of Parkinson’s patients who were not entirely typical, being in a special clinic because of the early development of dyskinesia, nausea, 3. McGrae, J. D., Perry, H. O. Archs Derm. 4. Menaker, M. Sci. Am. 1972, 226, 22. 5. Steven, D. M. Biol. Rev. 1963, 38, 204.
1963, 87, 252.