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THE BACILLUS OF PFEIFFER
191
extrasystoles
were
felt.
Postoperative electrocardiogram
was
normal.
It is obvious that, until some method is devised of the concentration of halothane in a closed circuit, this technique must be used with the greatest caution.. I would agree with Dr. Johnstone2 that most of the unpleasant reactions to halothane have been RRRocÎated with errors in technique. R. M. S. KEIR Dumfries and Galloway Royal Infirmary, R. B. S. Ross. Dumfries.
estimating
DOSAGE OF TOLBUTAMIDE
RENAL FAILURE FOLLOWING AORTOGRAPHY
SIR,-I note in your report of the Banting memorial meeting (July 20, p. 125) that you quote me as saying
that the optimal daily dose of tolbutamide in man was about 3 g. In fact, what I did say was that in a series of acute dose-response tests 3 g. of tolbutamide was more effective than 1 g. in producing hypoglycaemia, but when that dose was pushed to 6 g. the hypoglycsemic response became diminished. This finding implied that in man as well as in the laboratory animal, as shown by Mr. G. A. Stewart during the same meeting, tolbutamide appeared to possess a biphasic action depending upon its dose. The results of this acute dose-response test bear little relation to what one might consider the optimal daily dose therapeutically and in our experience it is of no use in the majority of patients to increase this beyond 1112g. per day. Certain arteriovenous studies reported at the meeting compared the lack of response to insulin and glucose in insulin-dependent diabetics with the response under the same conditions in diabetics controlled with tolbutamide. The results suggested insulin antagonism in the first 2IOUT).
Postgraduate Medical School of London and the Wellcome Foundation.
FREDERICK WOLFF.
THE BACILLUS OF PFEIFFER
Sir,-During the past few weeks I have noticed a marked increase of Hcemophilus influenzœ in throatswab cultures. The patients concerned are allergic in whom a routine bacteriological overhaul of subjects the upper respiratory tract is carried out, and with one exception none of them gave a history of any recent acute pyrexial respiratory illness. Direct and
" pathogen-selective "
cultures
are
It is of interest, if only one of coincidence, that in The Lancet exactly 39 years ago to the month the late Dr. John Matthewsreported finding H. influence in cultures-just prior to the major outbreaks of the 1918 influenza epidemic. Though long universally agreed that it plays no symbiotic setiological r6le with human influenza virusas does H. influenzae suis with swine influenza viruswhy does the Bacillus of Pfeiffer still persist in cropping up so regularly in association with human influenza ? DAVID HARLEY
made from
throat, post-nasal, and nasal swabs. The pathogen-selective
technique (Solis-Cohen) utilises the in-vitro bactericidal power of the patient’s fresh whole blood to kill off any organisms to which he is immune and to allow the growth of potentially pathogenic organisms, thus assisting in the differentiation of the setiologically important organisms from a mixed direct culture, in allergic cases with chronic or focal infection.
Though careful examination of direct blood-agar plate cultures from the throat and post-nasal space of such patients will often reveal a few colonies of H. influenzae in a mixed growth, in my experience it is uncommon to find that organism prominant or predominating. When it does so occur-usually during the winter monthsit comes up more in the post-nasal than in the throat culture, and rarely grows out in the pathogen-selective culture.
In the recent cases I refer to, H. influenzce was prominant in the direct throat culture (as well as in the post-nasal) and came through in heavy growth as the predominating or the only organism in the pathogenselective culture. Through the courtesy of your columns, I would be grateful for leave to inquire whether other clinical bacteriologists have had a similar experience, or whether this is just a chance happening.
SIR,-The excellent
accounts by Mr. Roy, Dr. and others in Dormandy, your issue of July 6 are but two examples of complications possibly arising from errors of technique for the cases in question. The well-established translumbar method of aortography has many disadvantages and dangers, not the least of which is the maldirection of too high a concentration and often too large a volume of contrast medium into the aorta at or near the origin of the renal arteries. Often only 15-20 ml. of a 30-35% strength of contrast medium will give very adequate results and 15-20 ml. of a 60% strength of contrast medium invariably gives excellent films of good diagnostic quality. If it is known, from a previous intravenous pyelogram, that one kidney functions poorly or not at all, still further caution is demanded during aortography and only a small volume, not more than 15 ml.-of one of the less toxic media such as’Urografin’ 60%-should be used to protect the normal kidney from damage. The Seldinger method of aortography is now widely practised but caution is needed here also because the tip of the catheter may, under the influence of the injection pressure, point towards the mouth of a main renal or accessory renal artery and a large volume of the medium may be injected into the artery. At Addenbrooke’s Hospital, we have demonstrated this cathetertip movement on occasions by means of cineradiology ; moreover, maldirection of the catheter tip is more likely to occur and should be guarded against in a tortuous aorta. It has, therefore, been our practice to place the catheter tip at an estimated point some 11/2-2 in. below the hila of the kidneys for non-selective renal arteriography and to allow free mixing of contrast medium with the aortic blood-stream, allowing the injection pressure to fill the segment of aorta adjacent to the renal arteries. The same caution with regard to the amount and concentration of contrast medium (15-20 ml., 60% urografin) should be observed as with the translumbar route. We consider the injection of a 75% medium quite unnecessary and we have long since abandoned it for arteriography. Cognisant of the possible dangers of kidney damage following injection of an uncontrolled amount of contrast medium into the renal arteries, we at Addenbrooke’s Hospital have for the past 15 months adopted the method of selective catheterisation of the renal arteries, as advocated by Edholm and Seldingerand Odman,3 and have injected small amounts (4-5 ml.) of contrast medium of only an approximately 30% solution of urografin and have obtained renal arteriograms of excellent quality and detail. We have experienced no untoward effects using this technique and no renal complications have ensued. This method also avoids the other risks mentioned in your annotation of July 6. A detailed report of this work is to be published in the August issue of the British Journal of Radiology. Addenbrooke’s
Cambridge.
Hospital,
DUNCAN GREGG.
Lancet, 1918, ii, 91. Edholm, P., Seldinger, S. I. Acta radiol. Stockh. 1956, 45, 15. 3. Odman, P. Ibid, p. 1. 1. 2.
extrasystoles
were
felt.
Postoperative electrocardiogram
was
normal.
It is obvious that, until some method is devised of the concentration of halothane in a closed circuit, this technique must be used with the greatest caution.. I would agree with Dr. Johnstone2 that most of the unpleasant reactions to halothane have been RRRocÎated with errors in technique. R. M. S. KEIR Dumfries and Galloway Royal Infirmary, R. B. S. Ross. Dumfries.
estimating
DOSAGE OF TOLBUTAMIDE
RENAL FAILURE FOLLOWING AORTOGRAPHY
SIR,-I note in your report of the Banting memorial meeting (July 20, p. 125) that you quote me as saying
that the optimal daily dose of tolbutamide in man was about 3 g. In fact, what I did say was that in a series of acute dose-response tests 3 g. of tolbutamide was more effective than 1 g. in producing hypoglycaemia, but when that dose was pushed to 6 g. the hypoglycsemic response became diminished. This finding implied that in man as well as in the laboratory animal, as shown by Mr. G. A. Stewart during the same meeting, tolbutamide appeared to possess a biphasic action depending upon its dose. The results of this acute dose-response test bear little relation to what one might consider the optimal daily dose therapeutically and in our experience it is of no use in the majority of patients to increase this beyond 1112g. per day. Certain arteriovenous studies reported at the meeting compared the lack of response to insulin and glucose in insulin-dependent diabetics with the response under the same conditions in diabetics controlled with tolbutamide. The results suggested insulin antagonism in the first 2IOUT).
Postgraduate Medical School of London and the Wellcome Foundation.
FREDERICK WOLFF.
THE BACILLUS OF PFEIFFER
Sir,-During the past few weeks I have noticed a marked increase of Hcemophilus influenzœ in throatswab cultures. The patients concerned are allergic in whom a routine bacteriological overhaul of subjects the upper respiratory tract is carried out, and with one exception none of them gave a history of any recent acute pyrexial respiratory illness. Direct and
" pathogen-selective "
cultures
are
It is of interest, if only one of coincidence, that in The Lancet exactly 39 years ago to the month the late Dr. John Matthewsreported finding H. influence in cultures-just prior to the major outbreaks of the 1918 influenza epidemic. Though long universally agreed that it plays no symbiotic setiological r6le with human influenza virusas does H. influenzae suis with swine influenza viruswhy does the Bacillus of Pfeiffer still persist in cropping up so regularly in association with human influenza ? DAVID HARLEY
made from
throat, post-nasal, and nasal swabs. The pathogen-selective
technique (Solis-Cohen) utilises the in-vitro bactericidal power of the patient’s fresh whole blood to kill off any organisms to which he is immune and to allow the growth of potentially pathogenic organisms, thus assisting in the differentiation of the setiologically important organisms from a mixed direct culture, in allergic cases with chronic or focal infection.
Though careful examination of direct blood-agar plate cultures from the throat and post-nasal space of such patients will often reveal a few colonies of H. influenzae in a mixed growth, in my experience it is uncommon to find that organism prominant or predominating. When it does so occur-usually during the winter monthsit comes up more in the post-nasal than in the throat culture, and rarely grows out in the pathogen-selective culture.
In the recent cases I refer to, H. influenzce was prominant in the direct throat culture (as well as in the post-nasal) and came through in heavy growth as the predominating or the only organism in the pathogenselective culture. Through the courtesy of your columns, I would be grateful for leave to inquire whether other clinical bacteriologists have had a similar experience, or whether this is just a chance happening.
SIR,-The excellent
accounts by Mr. Roy, Dr. and others in Dormandy, your issue of July 6 are but two examples of complications possibly arising from errors of technique for the cases in question. The well-established translumbar method of aortography has many disadvantages and dangers, not the least of which is the maldirection of too high a concentration and often too large a volume of contrast medium into the aorta at or near the origin of the renal arteries. Often only 15-20 ml. of a 30-35% strength of contrast medium will give very adequate results and 15-20 ml. of a 60% strength of contrast medium invariably gives excellent films of good diagnostic quality. If it is known, from a previous intravenous pyelogram, that one kidney functions poorly or not at all, still further caution is demanded during aortography and only a small volume, not more than 15 ml.-of one of the less toxic media such as’Urografin’ 60%-should be used to protect the normal kidney from damage. The Seldinger method of aortography is now widely practised but caution is needed here also because the tip of the catheter may, under the influence of the injection pressure, point towards the mouth of a main renal or accessory renal artery and a large volume of the medium may be injected into the artery. At Addenbrooke’s Hospital, we have demonstrated this cathetertip movement on occasions by means of cineradiology ; moreover, maldirection of the catheter tip is more likely to occur and should be guarded against in a tortuous aorta. It has, therefore, been our practice to place the catheter tip at an estimated point some 11/2-2 in. below the hila of the kidneys for non-selective renal arteriography and to allow free mixing of contrast medium with the aortic blood-stream, allowing the injection pressure to fill the segment of aorta adjacent to the renal arteries. The same caution with regard to the amount and concentration of contrast medium (15-20 ml., 60% urografin) should be observed as with the translumbar route. We consider the injection of a 75% medium quite unnecessary and we have long since abandoned it for arteriography. Cognisant of the possible dangers of kidney damage following injection of an uncontrolled amount of contrast medium into the renal arteries, we at Addenbrooke’s Hospital have for the past 15 months adopted the method of selective catheterisation of the renal arteries, as advocated by Edholm and Seldingerand Odman,3 and have injected small amounts (4-5 ml.) of contrast medium of only an approximately 30% solution of urografin and have obtained renal arteriograms of excellent quality and detail. We have experienced no untoward effects using this technique and no renal complications have ensued. This method also avoids the other risks mentioned in your annotation of July 6. A detailed report of this work is to be published in the August issue of the British Journal of Radiology. Addenbrooke’s
Cambridge.
Hospital,
DUNCAN GREGG.
Lancet, 1918, ii, 91. Edholm, P., Seldinger, S. I. Acta radiol. Stockh. 1956, 45, 15. 3. Odman, P. Ibid, p. 1. 1. 2.