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RUBIDIUM AND DETECTION OFDUCHENNE CARRIERS

SIR,-Nagai et al.11 found the biological half-life ofrubidium to be lower in carriers of X-linked (Duchenne)muscular dystrophy (D.M.D.) than in normal subjects,and suggested its measurement might help their detection.Bradley et al.," in a more critical comparison of 4 provencarriers with 5 normal women, could not confirm thesefindings. We now offer the preliminary results of ourinvestigation of a larger series.

12 D.M.D. carriers, identified genetically and by serum-creatinine-phosphokinase assay,3 and 12 normal women ofcomparable age each received intravenously 4 !1-Ci of86RbCI from a fresh batch to minimise interference from

longer-lived substances. Whole-body radioactivity wasmeasured at fortnightly intervals for the next ten weeksby a six-detector scanning type of whole-body monitor.The biological half-life of rubidium in the carriers was

(d:0’5) 34-4-52-1 days (mean 41-84, standard deviation4-69) and in the normal women was (±0-5) 36-4-50-0 days(mean 43-27, standard deviation 4-09). A t test of sig-nificance of difference between means gave t= 0-0539

(22 d.f.), denoting no significance.Our findings thus show that there is no difference

between the biological half-lives of rubidium in D.M.D.carriers and in normal women, and that this test is of novalue in the detection of D.M.D. carriers.

Whole Body Monitor Unit,Southern General Hospital,

Glasgow G51.

Research Laboratory,Knightswood Hospital,Glasgow G13 2XG.

T. E. HILDITCH.

J. C. SWEETINW. H. S. THOMSON.

CLEIDOCRANIAL DYSOSTOSIS IN THEILIAD

SIR,-May I suggest a tentative diagnosis of the condi-tion present in Thersites (Iliad, 11, 216) ? In the lateC. M. Bowra’s translation,4 " He was the ugliest man whocame to Troy. He was bandylegged and lame in one foot.His shoulders were bent and met over his chest. Abovehe had an egg-shaped head and on it sprouted some scantyhairs." "

The description of the head is not apt. The bandy legsand talipes are not diagnostic. But the ability to bring theshoulders together in front of the chest is, I believe, foundonly in cleidocranial dysostosis.

M.R.C. Clinical Genetics Unit,Institute of Child Health,

30 Guilford Street,London WC1N 1EH. C. O. CARTER.

CUBAN REFUGEES AND MISSING c

TRIRADII

SIR,-With the great influx of Cuban refugees in Miami,Florida, there has appeared a curious dermatoglyphicfinding among these people. As a routine part of ourgenetic studies, dermatoglyphic classifications turned upwhat appeared to be a greater incidence of a missing ctriradius on the palms of patients affected with learningdisabilities or mental retardation. Therefore we organiseda dermatoglyphic control study on 90 male and 90 female

1. Nagai, T., Sugita, H., Iinuma, T. A., Furukawa, T., Yashiro, S.J. nucl. Med. 1969, 10, 1.

2. Bradley, W. G., Gardner-Medwin, D., Haggith, J., Walton, J. N.,Hesp, R. Archs Neurol. 1971, 25, 193.

3. Thomson, W. H. S. Clinica chim. Acta, 1969, 26, 207.4. Bowra, C. M. (translator). Homer. London, 1972.

apparently normal school-age children (11-12 years) ofCuban descent. The investigation did indeed show thatthe Cuban population has a higher frequency of missing ctriradii than controls. The percentages were:

The importance of the comparison of control prints andpatient prints is emphasised by the fact that a missing ctriradius is a diagnostic finding in the dermatoglyphics ofTurner’s syndrome.

In the process of classifying these prints four otherfeatures were investigated:

The dermal ridge patterns on individuals of Cubannationality seem to be similar to those of North Americanand United Kingdom individuals except for a slightincrease in the percentage of missing c triradii.

Mailman Center for ChildDevelopment,

University of Miami,Box 6, Biscayne Annex,

Miami, Florida 33152, U.S.A. J. SCHINDELER.

DIAGNOSIS OF TRACHEO-ŒSOPHAGEALFISTULA

SIR,-With the spread of intensive-care units, thenumber of critically ill patients on long-term respiratorassistance has dramatically risen over the past several years.Accordingly, indwelling endotracheal or tracheostomy tubeshave become much more common, and, with them, theirattendant complications, especially in the severely ill anddebilitated. The dreaded complication of a tracheo-cesophageal fistula secondary to a chronic indwellingtracheostomy tube is infrequent, but when it occurs canthreaten life if respirator dependence is total.The diagnosis of a tracheo-oesophageal fistula can be very

difficult when the patient is unable to leave the i.c.u. formore sophisticated radiological confirmation or whenremoval of the tube for bronchoscopy cannot be tolerated.The diagnosis can be confirmed fairly simply and effec-tively at the bedside by measuring the inspired-oxygensaturation (from the respirator) and the gastric-oxygensaturation (via a nasogastric tube). Since leakage is fromtrachea to oesophagus, considerable quantities of air

may be forced into the stomach with a positive-pressurerespirator. If a tracheo-oesophageal fistula exists, therefore,the oxygen concentration in inspired and gastric air willbe approximately equal.Measurements can be conveniently made by transiently

raising the inspired-oxygen concentration to 50-75%,1. Holt, S. B. The Genetics of Dermal Ridges. Springfield, Illinois,

1968.