279

Fig. 3-Ultrasonic drill. The flexible shaft (arrow) is seen at itspoint of attachment to the tip of the concentrating cone, whichis contiguous with the piezo-electric transducer.

impossible with existing techniques, since the stone proved tobe quite hard, and preparations were made to use the ultra-sonic drill. An especially large (5 cm) basket was constructed,and 3-L months after operation, the T-tube still being in place,a catheter containing the basket was passed into the biliarytree under fluoroscopic control. Once the basket extruded

beyond the tip of the catheter the stone was readily trapped init, and the flexible shaft of the ultrasonic drill was introducedthrough the lumen of the basket-shaft. The stone was repeat-edly drilled until it broke up, this event being signalled by thecollapse of the basket (fig. 2). One 8 mm fragment remainedwhich was readily removed with the basket alone two dayslater. Repeat T-tube cholangiography showed a normal post-operative biliary tree. The patient remains in good health.

DISCUSSION

The ultrasonic drill was designed to explore the possibilitiesof re-canalising arteries occluded by atherosclerosis. It isshown in fig. 3 and has been described elsewhere.2 The trans-ducer is external to the body and consists of a piezo-electriccrystal of lead-zirconium titanate held between two quarter-wave-length aluminium shoulder-stubs. The concentratingcone is catenoidal in form and one half-wavelength long. Theflexible transmission line is made of cobalt-nickel alloy (’Elgi-loy’) and electrical power is by a 100-watt extended frequencyaudio-power amplifier driven at 25 kHz.

There are clearly limitations to the angulation that thetransmission line can stand, and doubtless this will make mani-pulation less easy in some cases than in others. Heat dissipa-tion in the biliary tree is no problem, provided that each drill-ing sequence is limited to about 5 seconds, but a

circulating-saline-cooling-system is also available, and can beincorporated in the system. Experience with ureters has sug-gested that trauma and endothelial damage are not significanthazards. Perforation of the duct should not occur if the tip ofthe drill is kept within the confines of the basket, a require-ment that can be met by careful fluoroscopy. Intermittent cho-langiography can be performed during the procedure withappropriate catheter attachments.

As far as we know, this is the first time that ultrasonic en-ergy has been successfully used in this way in the biliary tree.The clinical implications are considerable.

Work on this project was supported by National Science Foundationgrant no. GR 22684 and by the Frijole Foundation.

Requests for reprints should be addressed to F.S.B., Department ofElectrical Engineering, University of Colorado, Boulder, Colorado,U.S.A.

REFERENCES

1. Mahorner, H., Bean, W. J. Ann. Surg. 1971, 173, 857.2. Davies, H., Schwartz, R., Pfister, R., Barnes, F. J. clin. Ultrasound, 1975,

2, 217.

Reviews of Books

Medical Records

Edited by BERNARD BENJAMIN, PH.D. London: Heinemann Medi-cal. 1977. Pp. 235.[6.50.

THE past thirty years have seen remarkable changes in thestatus of medical-records officers. From being isolated clerksstruggling to maintain primitive ledger-written notes, theyhave become heads of big departments dealing not only withimmensely more complex records systems but also with sec-retarial services, admissions, communications, and other out-patient organisation. This.is only partly due to the parkin-sonian expansility of administrative departments: chiefly itreflects the explosive increase of information about patientsthat clinicians, as well as administrators, find it necessary togather, link, store, analyse, and redistribute. The M.R.O.s havedone their best to educate themselves for these new responsibil-ities. The Association of Medical Records Officers, founded in1948, led the way with courses, examinations, and qualifica-tions. But up to now there has been no book for these studentsto use. Dr Benjamin’s book therefore fills a yawning gap-agap so wide that even if this had been a very bad book, whichit is not, it would have been welcome. To those for whom ithas been written, candidates for the A.M.R.o. examinations, itwill be indispensable. Readers of The Lancet, however, willlook at it from a different angle-as a source of informationabout the technicalities of record management to outsiders(administrators, research-workers, computer system designers,and, above all, members of medical-records committees). Thebook contains a great deal of information and advice that thesepeople cannot easily find elsewhere, but it is far from perfect.It has too many authors, all (except the editor) with onechapter only: quality is uneven and coordination imperfect(filing techniques are covered in detail three times). The bookshould have been within the compass of one author, or at leasta close collaboration by a few. But the good chapters are verygood. One deficiency is a lack of figures. How many files go toa metre of shelving; how large a store will hold a kilometre ofshelves; how much is a reasonable day’s work for an averageclerk doing admission registration, master index maintenance,or Hospital Activity Analysis entry to a computer terminal;how many staff will records departments of representative hos-pitals require and what fraction of the total budget should theyspend? A textbook should give some guidelines on such mat-ters, inexact and provisional though they must be. The editor’sown contribution (apart from a most useful straight accountof legal aspects) stands apart from the rest. He writes chieflyon statistics and information handling from the point of viewof central Government. He is particularly useful on indicessuch as bed occupancy, though his mathematical formulae mayfrighten some readers away from what is in fact a simple andlucid explanation. Much of what he says reflects his faith inthe use of computers to maintain a single unified record basedon the individual, no matter where his contact. His argumentsare powerful, but because no other theme of future technicaladvance is dealt with at all adequately they affect the balanceof the book. The medical-record system had two main cus-tomers-clinicians who provide its bulk input and use its out-put and administrators who use the extracted statistics. Sincethe book looks beyond the domestic techniques of the recordsoffice to central statistical issues, it should have had at leastone medical contributor: he or she might have highlightedways in which the clinical activities of records offices could beimproved and in which doctors could improve both theirrecord keeping and their use of records, and might havebalanced Benjamin’s chapters by speculation on future pro-gress from the medical viewpoint. A doctor needs to under-stand the information system available to him at least as wellas his stethoscope. Perhaps it will not be long before somechapters of this book are as familiar to the good M.R.C.P. candi-date as his cram book in cardiology.

280

A Handbook of Numerical and Statistical Techniques

J; H. POLLARD, School of Biological Sciences, Mcquarie, Austra-lia. London: Cambridge University Press. 1977. Pp. 349. 13.50.

THIS book is designed particularly for scientists who wish toanalyse data using a programmable calculator, mini-computer,or interactive terminal. Dr Pollard has also had in mind theincreasing number of people who use computer packages andwish to know a little more about what goes on inside the ma-chine. The special feature of the book is the opening sectionof seven chapters on numerical methods. Starting with a rapidsummary of useful mathematical results, this section coverssuch topics as round-off errors, solving equations, smoothingcurves, numerical integration and differentiation, and interpo-lation. Simple calculus and a degree of concentration arerequired: the results are rewarding. The remaining elevenchapters are on statistical methods. Simple descriptive tech-niques, such as frequency distributions, are taken as known,and the author provides an exhaustive catalogue of the morecommonly used methods, with all the formula;, instructions,and tables. The treatment of least squares, using simple matrixmethods, is particularly useful. The long chapter on tests is alittle lifeless, but serves its intended purpose as a source ofreference. It is regrettable that the author "accepts" a nullhypothesis when a non-significant result is obtained: at themost it should be tentatively entertained. In summary, this isa useful book, extremely well-produced, requiring rather moremathematical determination than most books on applied statis-tics, but with appropriate compensations.

Clinical RadiobiologyW. DUNCAN, F.R.C.R., University of Edinburgh and A. H. W.NIAS, D.M., Glasgow Institute of Radiotherapeutics and Oncol-ogy. Edinburgh: Churchill Livingstone. 1977. Pp. 226.[9.50.

TWENTY years ago quantitative techniques for culture ofmammalian cells became available, and this was followed bya rapid expansion of experimental work with cells derived fromtumours as well as from normal tissues. It seemed clear thenthat detailed scientific bases would soon be found for the prac-tice of radiotherapy which over the previous half century hadbeen based on painstaking clinical observation. This book is anaccount of what has been learnt, tailored primarily to theneeds of the radiation oncologist in training. Its main contentis a survey of the effects of ionising radiations on cells, normaland tumorous, human and animal, in vitro and in vivo. Itsteaching is orthodox and its writing intelligible. If occasionallyit seems to lack direction, this only reflects the fact that inten-sive study of cells provides only part of what the cancer thera-pist needs to know. The study of tissues is equally essential andbecause that is so much more difficult, progress there has beenmuch slower. Unfortunately there are really too manyslips-in physics (e.g., neutrons may disturb both positivelyand negatively charged material), in biology (e.g., vertebrae docontain active marrow), in medicine (e.g., the leukaemia riskfor radiation exposure in utero is much overstated), and inradiological protection (e.g., the I.C.R.P. limit on whole-bodydose for a population is wrongly described).

African Folk Medicine

Practices and Beliefs of the Bambara and Other Peoples. PASCALJAMES IMPERATO. Baltimore: York Press. 1977. Pp. 251$16.

IT may seem surprising that the Commissioner of Health forNew York City should produce a volume on medical anthro-pology, but Dr Imperato is well known for his researches inMali, where he worked for years as a medical officer and tookpart in campaigns for smallpox control and measles immunisa-tion. Travelling the length and breadth of the country he accu-mulated first-hand information on local beliefs and practices

relating to all aspects of health and disease; and he made spe-cific studies of folk medicine in two contrasting cities, Bamakoand Timbuctoo. He has written an authoritative and highlyreadable text whose value will certainly not be confined to stu-dents of the Bambara. For every chapter refers to the extensiveliterature on African medicine and draws attention to the simi-larities and contrasts between Mali and in other parts ofAfrica. Moreover, the structure of the book makes it easy foranyone with a special interest to read selectively and also tocontemplate the possible contribution which different cate-

gories of folk practitioners might make to medical care in thefuture. On this much debated question Dr Imperato neverallows his local sympathies to override his clinical and epide-miological judgment. The sections on traditional African sur-gery and dentistry and on smallpox and on the twin cult areunique, and his examination of the progressive influence ofIslam upon older African concepts of disease causation andtreatment deserves special mention. The book ends with anappendix on the major public-health problems of Africa.

MyelinEdited by PIERRE MORELL, University of North Carolina. NewYork and London: Plenum. 1977. Pp. 531.$47.40.

ANYONE interested in the problems of demyelinating diseaseswill find this book essential reading. It provides a refreshing in-terdisciplinary approach to the subject and includes authori-tative chapters on neuropathy, genetic errors, experimentalpathology, and immunology of myelin. However, basic neuro-scientists will also find this a most stimulating book, for

although it deals with a rather specialised subject, myelin is anabundant and convenient membrane to study. As a result,there are chapters on chemistry and biophysics as well as thephysiology of saltatory conduction. The text is well supportedby electron micrographs, imaginative diagrams, detailed tablesof biochemical composition, electrophysiological traces, neuro-pathological sections (gross and microscopic), and illustrativeclinical case-histories. One neglected area is peripheral-nervemyelin, but this is covered in books on peripheral neuropathy.The book brings together contributions on so many differentfacets concerning the most abundant membrane of the nervoussystem.

Psychiatry on Trial

MALCOLM LADER, F.R.C.PSYCH. Harmandsworth: Penguin. 1977.Pp.202.80p.

Dr Lader is a distinguished psychiatrist with an interna- Itional reputation in psychopharmacology. He is not an anti-psychiatrist, but, as he says himself, an anti-humbug. In this i

little book he examines with his usual clarity some of the con-fusion which surrounds both the theory and practice of psychi-atry, and how sloppy and pretentious thinking endanger boththe patient’s treatment and liberty. His message is that soggy "

thoughts make for dangerous quagmires and, in certain politi- !cal circumstances, can create a tragic morass as large as theGulag Archipelago. Dr Lader acted as symposium adviser tothe World Psychiatric Association from 1967 to 1973. He

resigned because he was convinced that Soviet psychiatristswere abusing their professional positions, and he wanted to say J

so more loudly and more clearly than did the W.P.A. at thattime. Four of his twelve chapters are devoted to the evidenceand background of this abuse, and he gives a sympatheticaccount of the W.P.A.’s dilemma in responding to it. This bookdiscusses important issues with clarity and avoids too many ;

misleading simplifications. It can be strongly recommended to any interested citizen, and should be compulsory reading for Ithose going to this year’s W.P.A. congress in Honolulu.

281

THE LANCET

Nitrate and Human Cancer

No laboratory animal has so far proved immuneto the carcinogenic action of the N-nitroso com-pounds1,2 2 (N-nitrosamines and N-nitrosamides),but their direct incrimination in human cancer has

proved difficult. N-nitroso compounds are ubiqui-tous in the environment’-5 and, though they maycontribute to the general background level of

cancer, they have not been linked to cancer of anysingle site. They can also be formed in vivo, fromnitrite and secondary amine or amide in the acidstomach of animals6,7 and man, or as a result ofbacterial action in the achlorhydric stomach of ani-mals’ and in the infected urinary bladder of ani-malslO and many,12 Secondary amines and amidesare derived from the diet or from endogenous sour-ces ; nitrite is derived solely from dietary nitrate ornitrite, nitrate being overwhelmingly the more im-portant.

If endogenously produced N-nitroso compoundsare important in human cancer, populations con-suming large amounts of dietary nitrate shouldhave high incidences of cancer of the relevant tar-get organ (which is unknown for any N-nitrosa-mine in man). The main sources of dietary nitrateare vegetables and drinking water,13 with curedmeat products such as bacon, ham, and sausagesalso contributing in Western countries. There isnow considerable evidence that populations con-suming large amounts of nitrate do tend to havehigh mortality-rates from gastric cancerY-19 In one

1. Magee, P. N., Barnes, J. M. Adv. Cancer Res. 1967, 10, 163.2. Druckrey, H., Schildbach, A., Schmahl, D., Preussmann, R., Ivankovic, S.

Arzneimittel-Forsch. 1963, 13, 841.3. Crosby, N. T., Foreman, J. K., Palframan, J. F., Sawyer, R. Nature, 1972,

238, 342.4. Ayanaba, A., Alexander, M. Appl. Microbiol. 1973, 25, 862.5. Hoffman, D., Rathkamp, G., Liu, Y. Y. N-nitroso Compounds in the En-

vironment (edited by P. Bogovski and E. A. Walker), p. 159. Lyon, 1974.6. Mirvish, S. S. J. natn. Cancer Inst. 1971, 46, 1183.7. Mirvish, S. S., Chu, C. ibid. 1973, 50, 745.8. Sander, J , Schweinsburg, F. Abl. Bakt. Hyg. 1972, 156B, 299.9. Alam, B. S., Saporaschetz, I. B., Epstein, S. S. Nature, 1971, 232, 116.

10. Hawksworth, G. M., Hill, M. J. Br. J. Cancer, 1971, 25, 520.11. Brooks, J. B., Cherry, W. B., Thacker, L., Alley, C. C. J. inf. Dis. 1972, 126,

143.12. Hicks, R. M., Walters, C. L., Elsebai, I., ElAasser, A-B, Merzebani, M.,

Gough, T. Proc. R. Soc. Med. 1977, 70, 413.13. Ashton, M. B.F.M.I.R.A Literature Survey no. 7, 1970.14. Hill, M. J., Hawksworth, G. M., Tattersall, G. Br. J. Cancer, 1973, 28, 562.15. Hawksworth, G. M., Hill, M. J., Gordillo, G., Cuello, C. in N-nitroso Com-

pounds in the Environment (edited by P. Bogovski and E. A. Walker); p.229. Lyon, 1974.

16. Armijo, R., Coulson, A. Int. J. Epidem. 1975, 4, 301.17. Zaldivar, R., Robinson, H. Z. Krebsforsch. 1973, 80, 289.18. Cuello, C., Correa, P., Haenszel, W., Gordillo, G., Brown, C., Archer, M.,

Tannenbaum, S. J. natn. Cancer Inst. 1976, 57, 1015.19. Haenszel, W., Kurihara, M., Locke, F. B., Shimuzu, K., Segi, M. ibid. 1976,

56, 265.

study13 the high level of nitrate (which was princi-pally from drinking-water) was also linked to

above-average mortality from cancer of the

oesophagus, kidney, and liver. The others con-

cerned only gastric cancer. ARMIJO and COULSON16and ZALDIVAR and ROBINSON" studied the 17 pro-vinces of Chile where there is considerable varia-tion in the amount of nitrate fertiliser used (andtherefore the amount of nitrate in the vegetables). 2The correlation between the amount of nitrate fer-tiliser and the mortality-rate from gastric cancerwas 0.77; 16 a latency period of about fifteen yearscould be deduced 16 and a number of other factorsrelated to standard of living and socioeconomicstatus were shown to be correlated much less well,if at all, with mortality from gastric cancer. 16,17Two studies in Colombia1s,18 showed that, in anarea with a very high incidence of gastric cancer,the intake of nitrate from drinking-water and vege-tables was very much higher than in control areaswhere the gastric cancer incidence was much lower.In Japan persons drinking water from municipalsupplies, which contained low levels of nitrate, hada lower risk of gastric cancer’9 than persons drink-ing well water (which often has high nitrate con-centrations, although no measurements were madein this study).

These investigations offer only a few clues con-cerning the causation of the gastric cancer relatedto high nitrate consumption. In Chile and Colom-bia the prevalence of gastric achlorhydria in youngpersons is high, indicating that acid-catalysednitrosation is an unlikely explanation. CORREA eta1.2’ have suggested that an N-nitroso compoundproduced by stomach acid is responsible for thegastric atrophy in these persons and that the resul-tant achlorhydria allows the outgrowth of a pro-fuse gastric flora which can then produce furtherN-nitroso compounds and, finally, carcinogenesis.To support this they have shown that gastric atro-phy is very much more common in young personsliving in the high-incidence towns than in controlareas.22 A relation between gastric atrophy andgastric cancer has long been recognised and RuD-DELL et a1. 23 have shown that in the gastric juice ofachlorhydric persons the concentration of nitrite ishigh; since there is also an adequate concentrationof nitrosatable secondary amine24 and a profuseflora the conditions are very suitable for the forma-tion of N-nitrosamines by bacterial action in thestomach of these persons. The data obtained byHILL et al. 14 in Worksop, however, were more com-patible with the formation of N-nitrosamines in the

20. Schuphan, W., Schlotmann, H. Z. Lebensmitt u-Forsch. 1965, 128, 71.21. Correa, P., Haenszel, W., Cuello, C., Tannenbaum, S., Archer, M. Lancet,

1975, ii, 58.22. Haenszel, W., Correa, P., Cuello, C., Guzman, N., Burbano, L., Lores, H.,

Munoz, J. J. natn. Cancer Inst. 1976, 57, 1021.23. Ruddell, W. S. J., Bone, E. S., Hill, M. J., Blendis, L. M., Walters, C. L.

Lancet, 1976, ii, 1037.24. Walters, C. L. Unpublished.