814
BRITISH MEDICAL JOURNAL
In January 1970 a 56-year-old married man consulted me with his 50-year-old wife. The man, a dyestuffs worker, complained of a three-day history of frequency of micturition, dysuria, offensive urine, and pain in the left testicle. His wife complained of a two-day history of frequency of micturition, dysuria, right loin pain, offensive urine, and "flu-like" symptoms. Both patients had suffered similar attacks before and both on this occasion blamed sexual intercourse, which had occurred four days previously. Haematological examination revealed a leucocyte count of 17 x 109/l (17 000/mm3) (10 o neutrophils) in the man and 9 x 109/1 (9000/mm3) (870o neutrophils) in the woman. Urine examination revealed that both patients were infected with Escherichia coli serogroup 06, which was present in concentration greater than 108/1. A rectal swab was taken from the man and rectal and vaginal swabs were taken from his wife. E coli serogroup 06 was found in all of these. Subsequent and more detailed serological examination at the Salmonella Reference Laboratory, Colindale, revealed that the responsible organism was E coli serotype 06 Hi, which was isolated from all swabs except the rectal swab in the husband, from which no organism could be grown, presumably owing to loss in transit. That husband and wife had the same urinary pathogen would appear to be beyond dispute, but the pathogenesis of the infection in the man remains speculative. One interpretation of the facts is that the husband developed an ascending infection that was sexually transmitted in that he received an inoculum from the wife's vagina rather than his own bowel flora. Subsequent urological investigations revealed mild bladder neck obstruction only, but attacks (often associated with epididymitis) continued until vasectomy in 1971. This was the second such case I had encountered within a 12month period and subsequent inquiry among local colleagues revealed that other family practitioners had experienced the same phenomenon. Lt-Col Simpson suggests that prophylactic chemotherapy might be considered in this situation when a wife has urinary tract infection. If the above hypothesis is correct the results might be disappointing, as vaginal colonisation with a urinary pathogen might occur without urinary tract infection. Prophylactic chemotherapy might well be of value in selected men after intercourse, however. I acknowledge invaluable assistance from Dr G Garrett and Mr R Holihead, of Oldham Clinical Laboratories, and Dr Joan Taylor, Dr B Rowe, and Mr R J Gross, of the Salmonella Reference Laboratory, Colindale.
DAVID BROOKS Manchester
The elderly in a coronary unit
SIR,-One cannot deprecate too strongly the attitude of Dr B 0 Williams and his colleagues (21 August, p 451). It seems that their suggestions could deprive older patients of the facilities for which they have paid during the whole of their working lives through income tax, national insurance contributions, etc, in the interests of retaining the cost-effectiveness of a coronary care unit for younger patients. It is said that some Eskimos used to dispose of their elderly by leaving them in an igloo on an ice-floe. Many elderly have fought for
their country to enable it to retain the liberty of which we are now proud. One would have thought the benefits of civilisation for which these older patients have struggled merits, if not gratitude, then at least equal access to the facilities which, when used properly and successfully, will enable them to continue a useful life without gross residual disability, as this article shows. F FOSTER THOMPSON Whitley Hospital,
Coventry
"Press that bruise" SIR,-In the teaching and practice of first aid direct pressure on the site of bleeding is recognised as the method of choice in the control of haemorrhage. When I was teaching first aid I always added that the pressure should be kept up until the clotting time of blood had passed-namely, 3-5 min. I explained that the small leaks in the tiny blood vessels would by then be sealed off by blood clot and that this is the only way that the leak of blood is stopped at all. For many years I personally have used direct pressure immediately on bruises to prevent subcutaneous haemorrhage or leaking of lymph from the injured vessels. I have done this on myself and others and on children's bruises. The finger pinched in a door is exquisitely painful and may lead to loss of a nail from subungual bleeding. Immediate pressure prevents this, rendering the tissues bloodless; when the pressure is released there is no effusion or swelling and very little pain. My grandchildren, aged 4 and 2, now ask to have their own bruises pressed "like grandfather" with good results. This is, of course, what is done after surgery on the limbs under bloodless conditions, when a firm pressure bandage is applied before releasing the tourniquet. Talking to other doctors I have been surprised to find that this simple, immediate, truly first aid way of treating bruises apparently has not been taught or practised at all. I write this letter as I am sure that my slogan, "Press that bruise," should be broadcast. BASIL M TRACEY Norwich
Computer interrogation of patients SIR,-Reading the paper by Dr R W Lucas and others on this subject (11 September, p 623) I remembered the story of a patient who consulted an American psychiatrist. He began to give his history but the psychiatrist said that it would save him much time if the patient would kindly give his history into the tape recorder. The patient agreed, whereupon the psychiatrist proceeded to another assignment. A few minutes later, as he was leaving the building, he was surprised to encounter the patient, also leaving. The patient explained that as he had consulted so many different psychiatrists he had found it convenient to make a tape-recording of his clinical history and that he had therefore left his tape machine giving his history into the machine of the psychiatrist. Would it not be possible for the Glasgow researchers to develop a refinement of their method on these lines and so help further to purge medical practice of that most undesirable
2 OCTOBER 1976
element-human contact between doctor and patient ? A L JACOBS London N3
Sign language?
SIR,-I very much enjoyed your leading article "Beyond Calais" (11 September, p 606) but take issue with you on three counts regarding your observations on the word "semiology." Firstly, it is not synonymous with "symptomatology" because it concerns signs as well as symptoms, its etymological derivation being from the Greek word for sign. Secondly, it is far from obsolete since what other word embraces both symptoms and signs ? (I would agree that "semeiotics," which is equivalent to "symptomatology," is no longer needed.) And thirdly, while decrying "American English" in the following paragraph, you spell semeiology "semiology." F CLIFFORD ROSE London WI
Measurement of blood pressure
SIR,-In a survey of the blood pressure of 1037 men aged 45-70 years carried out by nurses using a random zero sphygmomanometer (on the left arm) as part of a multiphasic screening study in south-east London' we were surprised to find the following results. When phase IV (muffling of the Korotkoff sounds) was used to measure diastolic blood pressure the average level was 87 2 (SD 16 2) mm Hg. When phase V (disappearance of sounds) was used the average level was 771 (SD 12 6) mm Hg. There was thus, on average, a difference of 10 1 mm Hg between these two phases of blood pressure. Although differences between these phases have been reported before,' they have only been half as large and were found in studies carried out by doctors on much smaller samples. Dr Sergio Conceicao and his colleagues (10 April, p 886) suggest that faulty sphygmomanometer valves may be an important source of error in blood pressure measurement, and in a letter last year (9 August 1975, p 370) Dr R A Swallow drew attention to evidence that there might also be as much as 10 mm Hg difference between the right and left arms. The epidemiological literature on blood pressure measurement2 has of course documented many other possible sources of error, such as observer error and digit preference. Our purpose in emphasising the difference between phase IV and phase V readings is, however, related to the vexed decision of when to start people on antihypertensive therapy. Confusion as to which phase is used might have considerable health, economic, and social consequences. The best evidence available from controlled trials:' would suggest that in men a significant difference in clinical outcome is found on treating levels of diastolic blood pressure (phase V) of 105 mm Hg or more. Our own figures would suggest that 2 7", of men aged 40-65 years have these levels on a preliminary screening. If, in confusion, phase IV pressures were to be considered to be the same as phase V, no less than 11 51" of men would be categorised as having "levels of 105 mm Hg or more."
BRITISH MEDICAL JOURNAL
2 OCTOBER 1976
815
Our findings would suggest that it is most Later in your article confusion is introduced important that doctors record which phase by the mention of an upper limit (in undefined they are using, whether in clinical practice or in ppm) of vinyl chloride monomer (VCM) the reporting of therapeutic trials. concentration in polyvinyl chloride (PVC) used in fabrication. In this case we must presume M F D'SOUZA that ppm by weight (ppm (w/w)) is meant, but to many readers this may not be obvious. Department of Clinical Epidemiology in General Practice, It is far simpler to use units such as ,ug/l Brompton Hospital, and (equivalent to mg/M3) for air pollution thresDepartment of Community Medicine, St Thomas's Hospital Medical School, holds because the instruments used to monitor London pollution are most easily and reliably calibrated L M IRWIG in such mass/volume units. If such a convention National Research Institute for were generally adopted comparisons between Occupational Diseases, work from different laboratories would be less Johannesburg, South Africa subject to confusion because uncertainties in the definition of the concentration limits would 'D'Souza, M F, Swan, A V, and Shannon, D J, be eliminated. Similarly it would be less Lancet, 1976, 1, 1228. 2 Reid, D D, et al, Lancet, 1966, 1, 614. confusing to discuss VCM concentrations in Veterans Administration Cooperative Study Group on Hypotensive Agents, Joiirnal of the Americani Medi- PVC in terms such as jtg/g or mg/kg. cal Associationi, 1970, 213, 1143.
(5) Normal rats with hyperphosphataemia and hypocalcaemia due to repeated oral administration of phosphate are more sensitive to calcitonin than untreated rats. It appears that our observations are in agreement with the findings of the authors mentioned above. We found that uraemia causes decreased calcitonin sensitivity, which may be counteracted by hyperphosphataemia. It is suggested, therefore, that careful consideration should be given to any reduction of plasma phosphorus in uraemic patients treated with chronic haemodialysis. J Szucs First Department of Medicine, Senumelweis University Medical School, Budapest, Hungary
2
Szucs, J, Horvath, T, and Steczek, Nephrology, 1974, 2, 161. SzUcs, J, Lanzcet, 1974, 1, 1108.
K, Clinical
J, Horvath, T, and Steczek, K, Magyar JOHN S ROBINSON 3Sziics, Belorvosi Archivu?in, 1975, 28, 240. JOHN M THOMPSON 4 Holl6, I, Szucs, J, and Steczek, K, Endocrinologie,
Out-of-hours calls in general practice SIR,-It never ceases to amaze me that a general practitioner is expected to be on call 24 hours a day, 365 days a year, and yet be able to come up bright-eyed and bushy-tailed to cope with any emergency. Legal restrictions are laid down on the number of hours that airline pilots, lorry-drivers, etc may work. Yet GPs who equally hold human lives in their hands are expected to carry on regardlesspossibly paying the penalty of a mistake through fatigue before a service committee or in the law courts. Now that the tendency is towards larger group practices and duty-rosters surely it is time that a "shift system" is introduced, with financial encouragement from the Department. It would not be impossible to work a system in which one man in a group was on duty from 6 pm to 8 am for, say, a week, leaving his colleagues to cope with the day work. Personalised continuity of care is all very commendable, but a fresh, alert doctor is safer and more use to the ill patient. D HOOKER Truro
Vinyl chloride: the carcinogenic risk SIR,-We were pleased to read your wellbalanced leading article on the carcinogenicity of vinyl chloride (17 July, p 134). In one respect, however, your discussion of ceiling and threshold limits is misleading and likely to confuse those amongst your readers who are not pollution specialists. We have previously discussed the problems caused by using parts per million (ppm) in an unspecified manner in connection with the pollution of operating theatre atmospheres.' Vinyl chloride behaves as a non-ideal gas at room temperature. The ppm unit to which you refer, we presume, is by volume: ppm (v/v). This unit is generally rather loosely used but frequently this ratio is meant to be ppm (ideal volume/ideal volume) without actually being defined. Because of the non-ideality of vinyl chloride vapour a given mass occupies less volume at any particular temperature and partial pressure than predicted by the ideal gas laws. Although the resultant error arising from the use of ppm (ideal v/v) may be small, precision is essential in establishing the threshold and ceiling limits if defined safety levels are to be meaningful.
1971, 58, 326.
Department of Anaesthetics,
RONALD BELCHER WILLIAM I STEPHEN
Postinfluenzal depression
Department of Chemistry,
University of Birmingham
Robinson, J S, et al, British J7ournal of 1976, 48, 167.
SIR,-This is a syndrome which everyone Anzaesthesia, knows about (leading article, 21 August, p 440)
Hypophosphataemic osteomalacia in patients receiving haemodialysis SIR,-Dr J F Mahony and his colleagues (17 July, p 142) reported four uraemic patients with depletion hypophosphataemia and osteomalacia. Three of them had used aluminium hydroxide as antacid while the fourth had not. Dr K Y Ahmed and others (28 August, p 526) reported four patients with persistent predialysis hypophosphataemia in whom osteomalacia developed without their having taken oral phosphate binders. Dr M Cochran and his colleagues (14 August, p 396) examined the action of calcitonin in uraemia and pointed out the role of elevated plasma phosphorus in the observed increase in sensitivity to the hormone in nine of 17 patients. In connection with these publications we would like to report the conclusions reached from our studies of the role of calcitonin in the development of uraemic bone disease.' 3 (1) In chronically uraemic rats four weeks after subtotal nephrectomy calcitonin sensitivity seems to be decreased if the animal is nearly normophosphataemic, calcitonin sensitivity being measured by examining the decrease in serum calcium concentration after the intraperitoneal administration of calcitonin. (2) In these animals the calcaemic reaction (that is, the duration of hypercalaemia after an intraperitoneal calcium load, which seems to be a measure of endogenous calcitonin activity) lasts longer than in intact, pair-fed, agematched controls. (3) In patients with histologically established chronic renal glomerular disease with proteinuria and normocalcaemia but without elevated serum creatinine, phosphorus, or blood urea nitrogen values the elevation of serum calcium after an intravenous calcium load4 lasts longer than in healthy individuals. This may point to the early beginning of diminished calcitonin sensitivity in the course of chronic renal failure. (4) The anephric, uraemic rat with highly elevated plasma phosphorus seems to be more sensitive to calcitonin than the intact one.
but on which it seems impossible to get any worthwhile information. Having an interest in cerebral complications of influenza I have tried to find evidence for it. I wrote several years ago to a number of Birmingham practitioners at a time when influenza was prevalent but was unable to find any convincing case of postinfluenzal depression. Excellent records of epidemics since 1880 have been kept by the Birmingham Public Health Department and for more recent years the virus type is known. With the valuable help of a psychiatrist, Dr A Orwin, I went through the records of a major psychiatric hospital and could find no correlation between numbers of admissions for depression and occurrence of influenza outbreaks; such admissions were not more frequent at the time of epidemics, nor were waves of influenza followed by detectable waves of depressive illness at any interval afterwards. Surely one ought to be able to get precise information, something better than anecdotes on single cases, on a subject everyone knows about? Can anyone help me? T H FLEWETT Regional Virus Laboratory, East Birmingham Hospital, Birningham
Ingrowing toenail
SIR,-The operation for ingrowing toenail advocated by Mr B V Palmer and Mr D L Stevenson (7 August, p 367) is the classic wedge excision operation described by WatsonCheyne over sixty years ago' and repeatedly described with various modifications since then.2-4 However, as I pointed out in 1958,5 this operation is both inefficient and illogical. It is inefficient because the deeply placed germinal matrix, which it is most important to excise, is the least well exposed. It is illogical because embedding is caused by pressure of the nail against the nail wall and it is unnecessary to remove both the factors in a disorder due to two incompatible factors; if the nail edge is eliminated then the sepsis in the nail wall will always subside.
BRITISH MEDICAL JOURNAL
In January 1970 a 56-year-old married man consulted me with his 50-year-old wife. The man, a dyestuffs worker, complained of a three-day history of frequency of micturition, dysuria, offensive urine, and pain in the left testicle. His wife complained of a two-day history of frequency of micturition, dysuria, right loin pain, offensive urine, and "flu-like" symptoms. Both patients had suffered similar attacks before and both on this occasion blamed sexual intercourse, which had occurred four days previously. Haematological examination revealed a leucocyte count of 17 x 109/l (17 000/mm3) (10 o neutrophils) in the man and 9 x 109/1 (9000/mm3) (870o neutrophils) in the woman. Urine examination revealed that both patients were infected with Escherichia coli serogroup 06, which was present in concentration greater than 108/1. A rectal swab was taken from the man and rectal and vaginal swabs were taken from his wife. E coli serogroup 06 was found in all of these. Subsequent and more detailed serological examination at the Salmonella Reference Laboratory, Colindale, revealed that the responsible organism was E coli serotype 06 Hi, which was isolated from all swabs except the rectal swab in the husband, from which no organism could be grown, presumably owing to loss in transit. That husband and wife had the same urinary pathogen would appear to be beyond dispute, but the pathogenesis of the infection in the man remains speculative. One interpretation of the facts is that the husband developed an ascending infection that was sexually transmitted in that he received an inoculum from the wife's vagina rather than his own bowel flora. Subsequent urological investigations revealed mild bladder neck obstruction only, but attacks (often associated with epididymitis) continued until vasectomy in 1971. This was the second such case I had encountered within a 12month period and subsequent inquiry among local colleagues revealed that other family practitioners had experienced the same phenomenon. Lt-Col Simpson suggests that prophylactic chemotherapy might be considered in this situation when a wife has urinary tract infection. If the above hypothesis is correct the results might be disappointing, as vaginal colonisation with a urinary pathogen might occur without urinary tract infection. Prophylactic chemotherapy might well be of value in selected men after intercourse, however. I acknowledge invaluable assistance from Dr G Garrett and Mr R Holihead, of Oldham Clinical Laboratories, and Dr Joan Taylor, Dr B Rowe, and Mr R J Gross, of the Salmonella Reference Laboratory, Colindale.
DAVID BROOKS Manchester
The elderly in a coronary unit
SIR,-One cannot deprecate too strongly the attitude of Dr B 0 Williams and his colleagues (21 August, p 451). It seems that their suggestions could deprive older patients of the facilities for which they have paid during the whole of their working lives through income tax, national insurance contributions, etc, in the interests of retaining the cost-effectiveness of a coronary care unit for younger patients. It is said that some Eskimos used to dispose of their elderly by leaving them in an igloo on an ice-floe. Many elderly have fought for
their country to enable it to retain the liberty of which we are now proud. One would have thought the benefits of civilisation for which these older patients have struggled merits, if not gratitude, then at least equal access to the facilities which, when used properly and successfully, will enable them to continue a useful life without gross residual disability, as this article shows. F FOSTER THOMPSON Whitley Hospital,
Coventry
"Press that bruise" SIR,-In the teaching and practice of first aid direct pressure on the site of bleeding is recognised as the method of choice in the control of haemorrhage. When I was teaching first aid I always added that the pressure should be kept up until the clotting time of blood had passed-namely, 3-5 min. I explained that the small leaks in the tiny blood vessels would by then be sealed off by blood clot and that this is the only way that the leak of blood is stopped at all. For many years I personally have used direct pressure immediately on bruises to prevent subcutaneous haemorrhage or leaking of lymph from the injured vessels. I have done this on myself and others and on children's bruises. The finger pinched in a door is exquisitely painful and may lead to loss of a nail from subungual bleeding. Immediate pressure prevents this, rendering the tissues bloodless; when the pressure is released there is no effusion or swelling and very little pain. My grandchildren, aged 4 and 2, now ask to have their own bruises pressed "like grandfather" with good results. This is, of course, what is done after surgery on the limbs under bloodless conditions, when a firm pressure bandage is applied before releasing the tourniquet. Talking to other doctors I have been surprised to find that this simple, immediate, truly first aid way of treating bruises apparently has not been taught or practised at all. I write this letter as I am sure that my slogan, "Press that bruise," should be broadcast. BASIL M TRACEY Norwich
Computer interrogation of patients SIR,-Reading the paper by Dr R W Lucas and others on this subject (11 September, p 623) I remembered the story of a patient who consulted an American psychiatrist. He began to give his history but the psychiatrist said that it would save him much time if the patient would kindly give his history into the tape recorder. The patient agreed, whereupon the psychiatrist proceeded to another assignment. A few minutes later, as he was leaving the building, he was surprised to encounter the patient, also leaving. The patient explained that as he had consulted so many different psychiatrists he had found it convenient to make a tape-recording of his clinical history and that he had therefore left his tape machine giving his history into the machine of the psychiatrist. Would it not be possible for the Glasgow researchers to develop a refinement of their method on these lines and so help further to purge medical practice of that most undesirable
2 OCTOBER 1976
element-human contact between doctor and patient ? A L JACOBS London N3
Sign language?
SIR,-I very much enjoyed your leading article "Beyond Calais" (11 September, p 606) but take issue with you on three counts regarding your observations on the word "semiology." Firstly, it is not synonymous with "symptomatology" because it concerns signs as well as symptoms, its etymological derivation being from the Greek word for sign. Secondly, it is far from obsolete since what other word embraces both symptoms and signs ? (I would agree that "semeiotics," which is equivalent to "symptomatology," is no longer needed.) And thirdly, while decrying "American English" in the following paragraph, you spell semeiology "semiology." F CLIFFORD ROSE London WI
Measurement of blood pressure
SIR,-In a survey of the blood pressure of 1037 men aged 45-70 years carried out by nurses using a random zero sphygmomanometer (on the left arm) as part of a multiphasic screening study in south-east London' we were surprised to find the following results. When phase IV (muffling of the Korotkoff sounds) was used to measure diastolic blood pressure the average level was 87 2 (SD 16 2) mm Hg. When phase V (disappearance of sounds) was used the average level was 771 (SD 12 6) mm Hg. There was thus, on average, a difference of 10 1 mm Hg between these two phases of blood pressure. Although differences between these phases have been reported before,' they have only been half as large and were found in studies carried out by doctors on much smaller samples. Dr Sergio Conceicao and his colleagues (10 April, p 886) suggest that faulty sphygmomanometer valves may be an important source of error in blood pressure measurement, and in a letter last year (9 August 1975, p 370) Dr R A Swallow drew attention to evidence that there might also be as much as 10 mm Hg difference between the right and left arms. The epidemiological literature on blood pressure measurement2 has of course documented many other possible sources of error, such as observer error and digit preference. Our purpose in emphasising the difference between phase IV and phase V readings is, however, related to the vexed decision of when to start people on antihypertensive therapy. Confusion as to which phase is used might have considerable health, economic, and social consequences. The best evidence available from controlled trials:' would suggest that in men a significant difference in clinical outcome is found on treating levels of diastolic blood pressure (phase V) of 105 mm Hg or more. Our own figures would suggest that 2 7", of men aged 40-65 years have these levels on a preliminary screening. If, in confusion, phase IV pressures were to be considered to be the same as phase V, no less than 11 51" of men would be categorised as having "levels of 105 mm Hg or more."
BRITISH MEDICAL JOURNAL
2 OCTOBER 1976
815
Our findings would suggest that it is most Later in your article confusion is introduced important that doctors record which phase by the mention of an upper limit (in undefined they are using, whether in clinical practice or in ppm) of vinyl chloride monomer (VCM) the reporting of therapeutic trials. concentration in polyvinyl chloride (PVC) used in fabrication. In this case we must presume M F D'SOUZA that ppm by weight (ppm (w/w)) is meant, but to many readers this may not be obvious. Department of Clinical Epidemiology in General Practice, It is far simpler to use units such as ,ug/l Brompton Hospital, and (equivalent to mg/M3) for air pollution thresDepartment of Community Medicine, St Thomas's Hospital Medical School, holds because the instruments used to monitor London pollution are most easily and reliably calibrated L M IRWIG in such mass/volume units. If such a convention National Research Institute for were generally adopted comparisons between Occupational Diseases, work from different laboratories would be less Johannesburg, South Africa subject to confusion because uncertainties in the definition of the concentration limits would 'D'Souza, M F, Swan, A V, and Shannon, D J, be eliminated. Similarly it would be less Lancet, 1976, 1, 1228. 2 Reid, D D, et al, Lancet, 1966, 1, 614. confusing to discuss VCM concentrations in Veterans Administration Cooperative Study Group on Hypotensive Agents, Joiirnal of the Americani Medi- PVC in terms such as jtg/g or mg/kg. cal Associationi, 1970, 213, 1143.
(5) Normal rats with hyperphosphataemia and hypocalcaemia due to repeated oral administration of phosphate are more sensitive to calcitonin than untreated rats. It appears that our observations are in agreement with the findings of the authors mentioned above. We found that uraemia causes decreased calcitonin sensitivity, which may be counteracted by hyperphosphataemia. It is suggested, therefore, that careful consideration should be given to any reduction of plasma phosphorus in uraemic patients treated with chronic haemodialysis. J Szucs First Department of Medicine, Senumelweis University Medical School, Budapest, Hungary
2
Szucs, J, Horvath, T, and Steczek, Nephrology, 1974, 2, 161. SzUcs, J, Lanzcet, 1974, 1, 1108.
K, Clinical
J, Horvath, T, and Steczek, K, Magyar JOHN S ROBINSON 3Sziics, Belorvosi Archivu?in, 1975, 28, 240. JOHN M THOMPSON 4 Holl6, I, Szucs, J, and Steczek, K, Endocrinologie,
Out-of-hours calls in general practice SIR,-It never ceases to amaze me that a general practitioner is expected to be on call 24 hours a day, 365 days a year, and yet be able to come up bright-eyed and bushy-tailed to cope with any emergency. Legal restrictions are laid down on the number of hours that airline pilots, lorry-drivers, etc may work. Yet GPs who equally hold human lives in their hands are expected to carry on regardlesspossibly paying the penalty of a mistake through fatigue before a service committee or in the law courts. Now that the tendency is towards larger group practices and duty-rosters surely it is time that a "shift system" is introduced, with financial encouragement from the Department. It would not be impossible to work a system in which one man in a group was on duty from 6 pm to 8 am for, say, a week, leaving his colleagues to cope with the day work. Personalised continuity of care is all very commendable, but a fresh, alert doctor is safer and more use to the ill patient. D HOOKER Truro
Vinyl chloride: the carcinogenic risk SIR,-We were pleased to read your wellbalanced leading article on the carcinogenicity of vinyl chloride (17 July, p 134). In one respect, however, your discussion of ceiling and threshold limits is misleading and likely to confuse those amongst your readers who are not pollution specialists. We have previously discussed the problems caused by using parts per million (ppm) in an unspecified manner in connection with the pollution of operating theatre atmospheres.' Vinyl chloride behaves as a non-ideal gas at room temperature. The ppm unit to which you refer, we presume, is by volume: ppm (v/v). This unit is generally rather loosely used but frequently this ratio is meant to be ppm (ideal volume/ideal volume) without actually being defined. Because of the non-ideality of vinyl chloride vapour a given mass occupies less volume at any particular temperature and partial pressure than predicted by the ideal gas laws. Although the resultant error arising from the use of ppm (ideal v/v) may be small, precision is essential in establishing the threshold and ceiling limits if defined safety levels are to be meaningful.
1971, 58, 326.
Department of Anaesthetics,
RONALD BELCHER WILLIAM I STEPHEN
Postinfluenzal depression
Department of Chemistry,
University of Birmingham
Robinson, J S, et al, British J7ournal of 1976, 48, 167.
SIR,-This is a syndrome which everyone Anzaesthesia, knows about (leading article, 21 August, p 440)
Hypophosphataemic osteomalacia in patients receiving haemodialysis SIR,-Dr J F Mahony and his colleagues (17 July, p 142) reported four uraemic patients with depletion hypophosphataemia and osteomalacia. Three of them had used aluminium hydroxide as antacid while the fourth had not. Dr K Y Ahmed and others (28 August, p 526) reported four patients with persistent predialysis hypophosphataemia in whom osteomalacia developed without their having taken oral phosphate binders. Dr M Cochran and his colleagues (14 August, p 396) examined the action of calcitonin in uraemia and pointed out the role of elevated plasma phosphorus in the observed increase in sensitivity to the hormone in nine of 17 patients. In connection with these publications we would like to report the conclusions reached from our studies of the role of calcitonin in the development of uraemic bone disease.' 3 (1) In chronically uraemic rats four weeks after subtotal nephrectomy calcitonin sensitivity seems to be decreased if the animal is nearly normophosphataemic, calcitonin sensitivity being measured by examining the decrease in serum calcium concentration after the intraperitoneal administration of calcitonin. (2) In these animals the calcaemic reaction (that is, the duration of hypercalaemia after an intraperitoneal calcium load, which seems to be a measure of endogenous calcitonin activity) lasts longer than in intact, pair-fed, agematched controls. (3) In patients with histologically established chronic renal glomerular disease with proteinuria and normocalcaemia but without elevated serum creatinine, phosphorus, or blood urea nitrogen values the elevation of serum calcium after an intravenous calcium load4 lasts longer than in healthy individuals. This may point to the early beginning of diminished calcitonin sensitivity in the course of chronic renal failure. (4) The anephric, uraemic rat with highly elevated plasma phosphorus seems to be more sensitive to calcitonin than the intact one.
but on which it seems impossible to get any worthwhile information. Having an interest in cerebral complications of influenza I have tried to find evidence for it. I wrote several years ago to a number of Birmingham practitioners at a time when influenza was prevalent but was unable to find any convincing case of postinfluenzal depression. Excellent records of epidemics since 1880 have been kept by the Birmingham Public Health Department and for more recent years the virus type is known. With the valuable help of a psychiatrist, Dr A Orwin, I went through the records of a major psychiatric hospital and could find no correlation between numbers of admissions for depression and occurrence of influenza outbreaks; such admissions were not more frequent at the time of epidemics, nor were waves of influenza followed by detectable waves of depressive illness at any interval afterwards. Surely one ought to be able to get precise information, something better than anecdotes on single cases, on a subject everyone knows about? Can anyone help me? T H FLEWETT Regional Virus Laboratory, East Birmingham Hospital, Birningham
Ingrowing toenail
SIR,-The operation for ingrowing toenail advocated by Mr B V Palmer and Mr D L Stevenson (7 August, p 367) is the classic wedge excision operation described by WatsonCheyne over sixty years ago' and repeatedly described with various modifications since then.2-4 However, as I pointed out in 1958,5 this operation is both inefficient and illogical. It is inefficient because the deeply placed germinal matrix, which it is most important to excise, is the least well exposed. It is illogical because embedding is caused by pressure of the nail against the nail wall and it is unnecessary to remove both the factors in a disorder due to two incompatible factors; if the nail edge is eliminated then the sepsis in the nail wall will always subside.
