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EXPERIMENTAL TRANSMISSION OF SCRAPIE TO VOLES AND CHINESE HAMSTERS
232
In
England
The validity of comparing merit is so entrenched in notions of professional status that we are disturbed when we hear the mathematicians claim that the real problem is not how well such questions can be answered, but whether they can be asked at all. They raise troublesome issues such as the transitivity of relationships. It might be easier to ward off such attacks on factual grounds if negotiations on these issues were not usually confidential. It was refreshing, therefore, to find an actual record of a comparability exercise which had been carried out effectively, with admirable objectivity, and to almost everyone’s satisfaction. The evidence was found on a corner seat of the intercity express and concerned the proceedings of a distinction-award committee which had the task of comparing a surgeon, a physician, an obstetrician, and a dermatologist. Each was scored on a set of six criteria (godliness, cleanliness, handwriting, golf, and so on) for each of which he received a score in the range 0-6: our
Statistical analysis was difficult because the scores were not quantitative in a true sense and could not simply be added up without the risk that bne criterion might be weighted unfairly with respect to another; and in any case, the total scores were all the same. The committee noted that the surgeon had beaten the physician in four respects and conceded only in two. Likewise, the physician overcame the obstetrician, and the obstetrician defeated the dermatologist. And this was the order decided, and accepted amicably by those who received the awards. The only complaint was from the dermatologist (who somehow bugged the meeting). It seems he had used the same system to compare himself, favourably, with the surgeon. But then, as the chairman said, he was notoriously bad at arithmetic and his allegation was simply not possible. *
*
*
This morning our house-physician announced with some excitement that a very interesting patient had been admitted during the night" a woman with Hutchinson’s teeth ". These are not seen every day in our unit, so I decided to inspect the phenomenon, and was conducted to the bed followed by the registrar, senior house-officer, staff nurse, and a few students. Sure enough, the dear lady had peg-shaped teeth; I asked for a torch and prepared to discourse on the subject. Then the patient mumbled something and the word " false " was audible, but it was dismissed as irrelevant and I was about to examine her in a better light when she smilingly removed her dentures and said, " My dentist is a very clever man-he made these teeth exactly like my old ones." It was unanimously agreed that the dentist possessed not only talent but an unusual sense of humour. *
*
*
During the strike of Post Office workers I have been giving letters to outpatients to deliver to their doctors. As I sealed her letter, one patient asked: " Shall I read it now, doctor ?
"
*
*
*
" This year the Society decided to admit ladies to the We look forward to their participation in the affairs of the Society...."-Transactions of the Medical Society of London, 1970, 86.
Fellowship ...
Letters
Now
to
the Editor
IS THE KVEIM TEST SAFE ?
SIR,-Following the demonstration of an agent transmissible from Crohn’s disease tissueand from sarcoidosis tissue,2 should we not have some reservations about the Kveim test ? Although the active tissue is phenolised (0-25%) before injection,3 we cannot be entirely confident that infectivity is eliminated. One has in mind the hardiness of some as yet unidentified agent in kuru. The agent can withstand boiling, if cannibalism is the method of transmission,4 and formalin.5 In every case of transfer of kuru to monkeys 6-8 and mice,5 brain suspension was injected intracerebrally. In the passage of Crohn’s disease to mice the typical intestinal lesions were produced by footpad inoculation,l so inoculation in a distant site evidently confers no protection. There is at least one disorder, scrapie, in which the transmission agent-perhaps a slow virus 9 or an incomplete virus "—is known to be extremely tough, and it seems reasonable to act on the assumption that there may be others. Mitchell,discussing sources of Kveim-test material, writes: " Spleens should only be used from sarcoidosis patients with no history of transmissible or other relevant illness." Should this advice not be heeded ? Medical School, University of Newcastle upon Tyne.
MALCOLM WELLER.
EXPERIMENTAL TRANSMISSION OF SCRAPIE TO VOLES AND CHINESE HAMSTERS a degenerative disease of the central system which occurs naturally in sheep and goats, has been experimentally transmitted to mice, II golden hamsters,12 rats,13 and gerbils.144 Experiments at this institute now indicate that the vole and Chinese hamster are
SiR,—Scrapie,
nervous
susceptible to experimental scrapie. Field voles (Microtus agrestis) were obtained through the courtesy of Dr. Muldal, Christie Hospital, Manchester, and from Mr. Cowie-Whitney, M.R.E., Porton. In the first experiment, 6 young voles were inoculated intracerebrally with mouse-passaged scrapie brain material. 3 months after inoculation 2 voles died suddenly, and the results of histological examination of the brains were consistent with scrapie-i.e., status spongiosus and astrocytic hypertrophy. 4 months after inoculation a vole which appeared clinically normal was killed for examination, and the histological 3 voles died appearances were consistent with scrapie. early in the course of the experiment; the cause was not diagnosed. In the second experiment, 6 young voles were inoculated Mitchell, D. N., Rees, R. J. W. Lancet, 1970, ii, 168. Mitchell, D. N., Rees, R. J. W. ibid. 1969, ii, 81. Mitchell, D. N. in Recent Advances in Clinical Pathology (edited by S. C. Dyke); p. 431. London, 1968. 4. Glasse, R. M. Cannibalism in the Kuru Region. Department of Public Health, Territory of Papua & New Guinea (mimeographed report), 1963. 5. Field, E. J. Lancet, 1968, i, 981. 6. Gajdusek, D. C., Gibbs, C. J., Alpers, M. Nature, 1966, 209, 794. 7. Gajdusek, D. C., Gibbs, C. J., Alpers, M. Science, N.Y. 1967, 155, 212. 8. Gajdusek, D. C., Gibbs, C. J., Asher, D. M., David, E. ibid. 1968, 162, 693. 9. Palssen, P. A. in Slow, Latent and Temperate Virus Infections. National Institute of Neurological Diseases and Blindness, monograph no. 2. Washington, 1965. 10. Adams, D. H., Field, E. J. Lancet, 1968, ii, 714. 11. Chandler, R. L. Lancet, 1961, i, 1378. 12. Zlotnik, I. ibid. 1963, ii, 1072. 13. Chandler, R. L., Fisher, J. ibid. p. 1165. 14. Gibbs, C. J., Gajdusek, D. C. Proc. VI int. Congr. Neuropath. 1970, p. 779. 1. 2. 3.
233 brain material. 3 months after inoculation, 1 vole died without showing previous signs; histological examination of its brain did not reveal any abnormality. At this time another vole, which had shown no previous abnormal signs, developed obvious incoordination, including rapid jumping and turning movements; within six hours it appeared in extremis and was killed. Histological examination was consistent with scrapie. 3 further voles showed the same clinical signs, with sudden onset 3-32 months after inoculation; histological examinations were consistent with scrapie in all cases. The surviving vole, which appeared clinically normal, was then killed and again the histological examination was consistent with scrapie. In the third experiment, 6 young voles were inoculated with brain material from one of the voles of the second experiment. 2 months after inoculation, 2 voles showed signs of incoordination and were killed; histological changes consistent with scrapie were seen in 1 of these voles. A further case was similarly diagnosed at 3 months, and 3t months after inoculation 2 more cases occurred. The surviving vole was killed 4 months after inoculation; it appeared clinically normal, but histological examination was consistent with scrapie. Chinese hamsters (Cricetulus barabensis griseus) were used in the following scrapie studies. In two experiments a total of 15 Chinese hamsters were inoculated intracerebrally with mouse-passaged scrapie brain material. Clinical signs of incoordination, weakness, and lethargy were first recorded 6 months after inoculation, and within 9 months of inoculation all the Chinese hamsters had died or were killed. The results of histological examinations of the brain in all these cases were consistent with scrapie. In two further experiments a total of 16 Chinese hamsters were inoculated with rat-passaged scrapie material. Clinical signs commenced 412 months after inoculation, and 5 months after inoculation all the animals had died or were killed; all histological examinations were consistent with scrapie. The disease has now been passaged in Chinese hamsters. Experimental scrapie in the vole is of particular interest in its comparatively short period of onset and its obvious but short clinical stage. The disease in Chinese hamsters appears to have a shorter period of onset than in the golden hamster 2; the Chinese hamster has half the number of chromosomes of the golden hamster, and this may be relevant to cytogenetic work on scrapie. Both species may be of interest to those concerned with the transmission of human degenerative brain diseases to laboratory animals.
rat-passaged scrapie
with
Agricultural Research Council, Institute for Research Animal Diseases, Compton, Berks.
on
R. L. CHANDLER.
E.B.-VIRUS ANTIBODY IN CROHN’S DISEASE
E.B.V. ANTIBODY IN PATIENTS WITH
CROHN’S
DISEASE
that 100% of a large group of patients with sarcoidosis had detectable E.B.v. antibody and that in 79the antibody was present in high titre. We should like to report the E.B.v.-antibody findings in a E.B.v. group of British patients with Crohn’s disease. an indirect immunofluorescent (measured antibody by technique 9) was estimated in 30 such patients and in a similar number of controls matched for sex and age. All sera were coded and examined " blind ". The patients with Crohn’s disease, 13 men and 17 women, were aged from 15 to 67 years (mean 34 years). The diagnosis had been proved histologically in 21 patients; and all but 5 had clinical evidence of active disease. At the time of the investigation 13 patients were being treated with azathioprine (50-150 mg. daily). Of the remaining 17 patients, 4 were receiving corticosteroids. The matched controls were taken from a larger series of surgical inpatients (without known infectious mononucleosis, sarcoidosis, or malignant
disease) aged 15-65 years. Our findings, presented
in the accompanying table, with those of Dr. Grotsky and his colleagues. Firstly, unlike patients with sarcoidosis, those with Crohn’s disease were not 100% antibody-positive. Secondly, although the mean titre of patients not receiving azathioprine was slightly lower than that of patients receiving the drug, the mean titre of the Crohn’s disease group as a whole was closely comparable to that of the controls. No titre greater than 1/256 was observed. A surprising finding was the 100% antibody prevalence in the matched controls. However, in the larger group of surgical inpatients, antibody prevalence was closely similar to that in the Crohn’s disease group. The 100% prevalence in the matched controls would, therefore, appear to be a chance finding resulting from the small number studied. No difference in prevalence of positive titres was observed between Crohn’s disease patients on azathioprine therapy and those on other treatment, nor did azathioprine bring about any reduction in titre. Patients receiving " immunosuppressive therapy, including azathioprine, have previously been found to maintain adequate levels of immunoglobulins.10 We conclude that there are no significant abnormalities in the E.B.v.-antibody status of patients with Crohn’s disease.
concur
"
interested to read that Dr. Grotsky and his colleagues5 were unable to detect any significant difference in the prevalence of Epstein-Barr-virus (E.B.v.) antibody in American patients with Crohn’s disease as compared with controls. Their investigation followed the demonstration of a possible relationship between Crohn’s disease and sarcoidosis, since a significant number of British patients with Crohn’s disease have been found to be Kveim-positive. 6,7 Hirshaut et awl. had previously shown
SIR,-We
5. 6. 7. 8.
were
most
Grotsky, H., Glade, P. R., Hirshaut, Y., Sachar, D., Janowitz, H. D. Lancet, 1970, ii, 1256. Mitchell, D. N., Cannon, P., Dyer, N. H., Hinson, K. F. W., Willoughby, J. M. T. ibid. p. 496. Karlish, A. J., Cox, E. V., Hampson, F., Hemsted, E. H. ibid. p. 977. Hirshaut, Y., Glade, P., Vieira, L. O. B. D., Ainbender, E., Dvorak, B., Siltzbach, L. E. New Engl. J. Med. 1970, 283, 502.
We are indebted to Dr. H. P. Lambert for initiating this study; Prof. B. N. Brooke for encouragement and permission to investigate patients; and to Miss Y. Tryhorn for valuable technical assistance. F. J. N. is supported by the London Fever Hospital Research Fellowship. to
Surgical Unit and Communicable Diseases Unit, St. George’s Hospital, London S.W.7. 9. 10.
S. P. KANE
F. J. NYE.
Henle, G., Henle, W. J. Bact. 1966, 91, 1248. Swanson, M. A., Schwartz, R. S. New Engl. J. Med. 1967, 277, 163.
In
England
The validity of comparing merit is so entrenched in notions of professional status that we are disturbed when we hear the mathematicians claim that the real problem is not how well such questions can be answered, but whether they can be asked at all. They raise troublesome issues such as the transitivity of relationships. It might be easier to ward off such attacks on factual grounds if negotiations on these issues were not usually confidential. It was refreshing, therefore, to find an actual record of a comparability exercise which had been carried out effectively, with admirable objectivity, and to almost everyone’s satisfaction. The evidence was found on a corner seat of the intercity express and concerned the proceedings of a distinction-award committee which had the task of comparing a surgeon, a physician, an obstetrician, and a dermatologist. Each was scored on a set of six criteria (godliness, cleanliness, handwriting, golf, and so on) for each of which he received a score in the range 0-6: our
Statistical analysis was difficult because the scores were not quantitative in a true sense and could not simply be added up without the risk that bne criterion might be weighted unfairly with respect to another; and in any case, the total scores were all the same. The committee noted that the surgeon had beaten the physician in four respects and conceded only in two. Likewise, the physician overcame the obstetrician, and the obstetrician defeated the dermatologist. And this was the order decided, and accepted amicably by those who received the awards. The only complaint was from the dermatologist (who somehow bugged the meeting). It seems he had used the same system to compare himself, favourably, with the surgeon. But then, as the chairman said, he was notoriously bad at arithmetic and his allegation was simply not possible. *
*
*
This morning our house-physician announced with some excitement that a very interesting patient had been admitted during the night" a woman with Hutchinson’s teeth ". These are not seen every day in our unit, so I decided to inspect the phenomenon, and was conducted to the bed followed by the registrar, senior house-officer, staff nurse, and a few students. Sure enough, the dear lady had peg-shaped teeth; I asked for a torch and prepared to discourse on the subject. Then the patient mumbled something and the word " false " was audible, but it was dismissed as irrelevant and I was about to examine her in a better light when she smilingly removed her dentures and said, " My dentist is a very clever man-he made these teeth exactly like my old ones." It was unanimously agreed that the dentist possessed not only talent but an unusual sense of humour. *
*
*
During the strike of Post Office workers I have been giving letters to outpatients to deliver to their doctors. As I sealed her letter, one patient asked: " Shall I read it now, doctor ?
"
*
*
*
" This year the Society decided to admit ladies to the We look forward to their participation in the affairs of the Society...."-Transactions of the Medical Society of London, 1970, 86.
Fellowship ...
Letters
Now
to
the Editor
IS THE KVEIM TEST SAFE ?
SIR,-Following the demonstration of an agent transmissible from Crohn’s disease tissueand from sarcoidosis tissue,2 should we not have some reservations about the Kveim test ? Although the active tissue is phenolised (0-25%) before injection,3 we cannot be entirely confident that infectivity is eliminated. One has in mind the hardiness of some as yet unidentified agent in kuru. The agent can withstand boiling, if cannibalism is the method of transmission,4 and formalin.5 In every case of transfer of kuru to monkeys 6-8 and mice,5 brain suspension was injected intracerebrally. In the passage of Crohn’s disease to mice the typical intestinal lesions were produced by footpad inoculation,l so inoculation in a distant site evidently confers no protection. There is at least one disorder, scrapie, in which the transmission agent-perhaps a slow virus 9 or an incomplete virus "—is known to be extremely tough, and it seems reasonable to act on the assumption that there may be others. Mitchell,discussing sources of Kveim-test material, writes: " Spleens should only be used from sarcoidosis patients with no history of transmissible or other relevant illness." Should this advice not be heeded ? Medical School, University of Newcastle upon Tyne.
MALCOLM WELLER.
EXPERIMENTAL TRANSMISSION OF SCRAPIE TO VOLES AND CHINESE HAMSTERS a degenerative disease of the central system which occurs naturally in sheep and goats, has been experimentally transmitted to mice, II golden hamsters,12 rats,13 and gerbils.144 Experiments at this institute now indicate that the vole and Chinese hamster are
SiR,—Scrapie,
nervous
susceptible to experimental scrapie. Field voles (Microtus agrestis) were obtained through the courtesy of Dr. Muldal, Christie Hospital, Manchester, and from Mr. Cowie-Whitney, M.R.E., Porton. In the first experiment, 6 young voles were inoculated intracerebrally with mouse-passaged scrapie brain material. 3 months after inoculation 2 voles died suddenly, and the results of histological examination of the brains were consistent with scrapie-i.e., status spongiosus and astrocytic hypertrophy. 4 months after inoculation a vole which appeared clinically normal was killed for examination, and the histological 3 voles died appearances were consistent with scrapie. early in the course of the experiment; the cause was not diagnosed. In the second experiment, 6 young voles were inoculated Mitchell, D. N., Rees, R. J. W. Lancet, 1970, ii, 168. Mitchell, D. N., Rees, R. J. W. ibid. 1969, ii, 81. Mitchell, D. N. in Recent Advances in Clinical Pathology (edited by S. C. Dyke); p. 431. London, 1968. 4. Glasse, R. M. Cannibalism in the Kuru Region. Department of Public Health, Territory of Papua & New Guinea (mimeographed report), 1963. 5. Field, E. J. Lancet, 1968, i, 981. 6. Gajdusek, D. C., Gibbs, C. J., Alpers, M. Nature, 1966, 209, 794. 7. Gajdusek, D. C., Gibbs, C. J., Alpers, M. Science, N.Y. 1967, 155, 212. 8. Gajdusek, D. C., Gibbs, C. J., Asher, D. M., David, E. ibid. 1968, 162, 693. 9. Palssen, P. A. in Slow, Latent and Temperate Virus Infections. National Institute of Neurological Diseases and Blindness, monograph no. 2. Washington, 1965. 10. Adams, D. H., Field, E. J. Lancet, 1968, ii, 714. 11. Chandler, R. L. Lancet, 1961, i, 1378. 12. Zlotnik, I. ibid. 1963, ii, 1072. 13. Chandler, R. L., Fisher, J. ibid. p. 1165. 14. Gibbs, C. J., Gajdusek, D. C. Proc. VI int. Congr. Neuropath. 1970, p. 779. 1. 2. 3.
233 brain material. 3 months after inoculation, 1 vole died without showing previous signs; histological examination of its brain did not reveal any abnormality. At this time another vole, which had shown no previous abnormal signs, developed obvious incoordination, including rapid jumping and turning movements; within six hours it appeared in extremis and was killed. Histological examination was consistent with scrapie. 3 further voles showed the same clinical signs, with sudden onset 3-32 months after inoculation; histological examinations were consistent with scrapie in all cases. The surviving vole, which appeared clinically normal, was then killed and again the histological examination was consistent with scrapie. In the third experiment, 6 young voles were inoculated with brain material from one of the voles of the second experiment. 2 months after inoculation, 2 voles showed signs of incoordination and were killed; histological changes consistent with scrapie were seen in 1 of these voles. A further case was similarly diagnosed at 3 months, and 3t months after inoculation 2 more cases occurred. The surviving vole was killed 4 months after inoculation; it appeared clinically normal, but histological examination was consistent with scrapie. Chinese hamsters (Cricetulus barabensis griseus) were used in the following scrapie studies. In two experiments a total of 15 Chinese hamsters were inoculated intracerebrally with mouse-passaged scrapie brain material. Clinical signs of incoordination, weakness, and lethargy were first recorded 6 months after inoculation, and within 9 months of inoculation all the Chinese hamsters had died or were killed. The results of histological examinations of the brain in all these cases were consistent with scrapie. In two further experiments a total of 16 Chinese hamsters were inoculated with rat-passaged scrapie material. Clinical signs commenced 412 months after inoculation, and 5 months after inoculation all the animals had died or were killed; all histological examinations were consistent with scrapie. The disease has now been passaged in Chinese hamsters. Experimental scrapie in the vole is of particular interest in its comparatively short period of onset and its obvious but short clinical stage. The disease in Chinese hamsters appears to have a shorter period of onset than in the golden hamster 2; the Chinese hamster has half the number of chromosomes of the golden hamster, and this may be relevant to cytogenetic work on scrapie. Both species may be of interest to those concerned with the transmission of human degenerative brain diseases to laboratory animals.
rat-passaged scrapie
with
Agricultural Research Council, Institute for Research Animal Diseases, Compton, Berks.
on
R. L. CHANDLER.
E.B.-VIRUS ANTIBODY IN CROHN’S DISEASE
E.B.V. ANTIBODY IN PATIENTS WITH
CROHN’S
DISEASE
that 100% of a large group of patients with sarcoidosis had detectable E.B.v. antibody and that in 79the antibody was present in high titre. We should like to report the E.B.v.-antibody findings in a E.B.v. group of British patients with Crohn’s disease. an indirect immunofluorescent (measured antibody by technique 9) was estimated in 30 such patients and in a similar number of controls matched for sex and age. All sera were coded and examined " blind ". The patients with Crohn’s disease, 13 men and 17 women, were aged from 15 to 67 years (mean 34 years). The diagnosis had been proved histologically in 21 patients; and all but 5 had clinical evidence of active disease. At the time of the investigation 13 patients were being treated with azathioprine (50-150 mg. daily). Of the remaining 17 patients, 4 were receiving corticosteroids. The matched controls were taken from a larger series of surgical inpatients (without known infectious mononucleosis, sarcoidosis, or malignant
disease) aged 15-65 years. Our findings, presented
in the accompanying table, with those of Dr. Grotsky and his colleagues. Firstly, unlike patients with sarcoidosis, those with Crohn’s disease were not 100% antibody-positive. Secondly, although the mean titre of patients not receiving azathioprine was slightly lower than that of patients receiving the drug, the mean titre of the Crohn’s disease group as a whole was closely comparable to that of the controls. No titre greater than 1/256 was observed. A surprising finding was the 100% antibody prevalence in the matched controls. However, in the larger group of surgical inpatients, antibody prevalence was closely similar to that in the Crohn’s disease group. The 100% prevalence in the matched controls would, therefore, appear to be a chance finding resulting from the small number studied. No difference in prevalence of positive titres was observed between Crohn’s disease patients on azathioprine therapy and those on other treatment, nor did azathioprine bring about any reduction in titre. Patients receiving " immunosuppressive therapy, including azathioprine, have previously been found to maintain adequate levels of immunoglobulins.10 We conclude that there are no significant abnormalities in the E.B.v.-antibody status of patients with Crohn’s disease.
concur
"
interested to read that Dr. Grotsky and his colleagues5 were unable to detect any significant difference in the prevalence of Epstein-Barr-virus (E.B.v.) antibody in American patients with Crohn’s disease as compared with controls. Their investigation followed the demonstration of a possible relationship between Crohn’s disease and sarcoidosis, since a significant number of British patients with Crohn’s disease have been found to be Kveim-positive. 6,7 Hirshaut et awl. had previously shown
SIR,-We
5. 6. 7. 8.
were
most
Grotsky, H., Glade, P. R., Hirshaut, Y., Sachar, D., Janowitz, H. D. Lancet, 1970, ii, 1256. Mitchell, D. N., Cannon, P., Dyer, N. H., Hinson, K. F. W., Willoughby, J. M. T. ibid. p. 496. Karlish, A. J., Cox, E. V., Hampson, F., Hemsted, E. H. ibid. p. 977. Hirshaut, Y., Glade, P., Vieira, L. O. B. D., Ainbender, E., Dvorak, B., Siltzbach, L. E. New Engl. J. Med. 1970, 283, 502.
We are indebted to Dr. H. P. Lambert for initiating this study; Prof. B. N. Brooke for encouragement and permission to investigate patients; and to Miss Y. Tryhorn for valuable technical assistance. F. J. N. is supported by the London Fever Hospital Research Fellowship. to
Surgical Unit and Communicable Diseases Unit, St. George’s Hospital, London S.W.7. 9. 10.
S. P. KANE
F. J. NYE.
Henle, G., Henle, W. J. Bact. 1966, 91, 1248. Swanson, M. A., Schwartz, R. S. New Engl. J. Med. 1967, 277, 163.