PRENATAL TAY-SACHS DIAGNOSIS BY CHORIONIC VILLI SAMPLING

286 When strict criteria are not used the incidence will be higher. Mihatsch’s illustration of a giant mitochondrion does not meet the histological characteristics of mitochondria. cases.

Department of Pathology and Laboratory Medicine, Medical School, Health Science Center at Houston, Houston, Texas 77225, USA

processed cytotrophoblast tissue,2as well as of cultured vihi, revealed trisomy 16 and an XY sex chromosomal constitution. The pregnancy was terminated in the first trimester and the products of conception were cultured and analysed. The hexosaminidase A activity was 61%, and the karyotype confirmed trisomy 16 (47, XY+16). Further experience is needed to define the range of hexosaminidase A activities in chorionic villi relative to the affected, ’

REGINA VERANI

states of the Tay-Sachs gene. This case suggests that distinguishing between a conception affected by Tay. Sachs disease and an unaffected conception will be possible in the first trimester of pregnancy. EUGENE PERGAMENT NORMAN GINSBERG Division of Medical Genetics YURY VERLINSKY and Departments of Pathology ALAN CADKIN and Obstetrics and Gynecology, LAURA CHU Michael Reese Hospital,

carrier, and non-carrier NTD SCREENING BY ULTRASOUND

SIR,-Professor Roberts and his colleagues (June 11, p 1315), in their six year study in Mid Glamorgan, illustrate the many pitfalls and shortcomings associated with a general neural tube defect (NTD) screening policy designed around serum a-fetoprotein (AFP) assay. At about the same time as the Mid Glamorgan experiment began, we instituted in the Tayside region an ultrasound screening programme for the detection of NTDs at around 18 weeks’ gestation, having first decided to determine accurate gestational age by ultrasound at the time of booking. This programme is now completely accepted and integrated into antenatal care with no reliance whatsoever placed upon AFP readings. No amniocenteses are done, the definitive diagnoses being effected by careful ultrasound examination of the fetal head and spine. Mistakes have been made in the past though our efficacy has never been below 85% for NTDs, but improvements in apparatus and experience resulted in a 100% detection rate in 1982, twenty NTDs being diagnosed either at booking or at 18 weeks’ gestation. May I suggest that the concept of "normal service conditions" can be changed if the will exists, and that even a single ultrasound examination in early pregnancy will give much better detection rates than any cited so far for the serum AFP assay. Department of Obstetric Ultrasound, Ninewells Hospital and Medical School,

A. D. CHRISTIE

Dundee

PRENATAL TAY-SACHS DIAGNOSIS BY CHORIONIC VILLI SAMPLING

SIR,-We wish to report that prenatal diagnosis of Tay-Sachs disease is possible in the first trimester of pregnancy. A 35-year-old primagravida and her husband had been identified as carriers for the Tay-Sachs gene. Their hexosaminidase A activities in serum were 35% and 37%, respectively (carrier level 44±5%, non-carrier level 68±4%); leucocyte hexosaminidase A activities were 51% and 60%, respectively (carrier range 45-60%, non-carrier range 73-82%). The parents requested first trimester diagnosis by chorionic villi sampling, recognising that the risks of the procedure are unknown but also unwilling to deal with the 25% risk of selective abortion of an affected fetus at 20 weeks’ gestation determined through amniocentesis done 4 weeks earlier. Chorionic villi samplingl°2 has been done successfully on seventeen pregnancies not at risk for Tay-Sachs disease. Hexosaminidase A activity, determined by the heat inactivation technique, was 61 ±15% by direct analysis of thirteen chorionic villi samples and 59±16% after short-term culture (5-7 days), established after extended trypsinisation of five chorionic villi

samples (unpublished). Chorionic villi sampling of the pregnancy at risk for Tay-Sachs disease was done at 8’ 5 weeks’ gestation. About 40 mg of villi was obtained in four sampling attempts and used for both biochemical and chromosomal analyses. Hexosaminidase A activity was 54±13% by direct analysis of the chorionic villi and 58±12% after short-term tissue culture. These results indicated that the fetus was unaffected with Tay-Sachs disease. The parents had agreed to amniocentesis at 16 weeks to confirm the above results. However, karyotypic analysis of directly

Chicago, Illinois 60616, USA

SIR,-Chorionic villous tissue

for chromosomal or metabolic abnormalities in much the same way as cultured amnion cells are. The sampling technique is simple, and, within the limited experience so far available, apparently safe. It remains then to show, for each genetic disease of interest, that trophoblasts reliably reflect the fetal genotype. We have used polyacrylamide gel electrophoresis (PAGE) and DEAE cellulose chromatography, to examine hexosaminidase isozyme patterns of placental trophoblast tissue from four normal fetuses and from a fetus affected with Tay-Sachs disease and found that trophoblasts of the affected fetus did indeed manifest the genetic defect-ie, an absence of hexosaminidase A. Chorionic villi from normal pregnancies were obtained by transcervical aspiration from patients undergoing elective first trimester abortions. Villi from a pregnancy found to be affected with Tay-Sachs disease through standard transabdominal amniocentesis were obtained at 16 weeks’ gestation by both transcervical aspiration and directly from the placenta at the time of termination. Villi were washed successively in RPMI medium 1640 and 0 - 87To saline, and suspended in 087% saline. Extracts were prepared by homogenisation followed by freeze-thawing three times. The homogenates were centrifuged at 1300 g, and the supernatant solutions used directly for PAGEor, after dialysis, for DEAE cellulose chromatography. Extracts of normal trophoblasts showed peaks of both hexosaminidase A and B activity characteristic of those seen in normal cultured fibroblasts and amnion cells. Extracts ofTay-Sachs trophoblasts showed the absence of hexosaminidase A (see figure) which agreed with results from cultured fibroblasts from the abortus. The isozyme patterns of normal trophoblast extracts differed from those of fibroblast and amnion cell extracts only quantitatively in that amnion cell extracts contained a higher percentage of hexosaminidase A. The four normal trophoblast samples we analysed had a mean value of 28%, while normal cultured amnion cells had a mean value of 53%. The clear absence of hexosaminidase A in trophoblasts from the affected fetus suggests that they will be as satisfactory as cultured amnion cells or amniotic fluid for diagnosing fetal Tay-Sachs disease. The absence of hexosaminidase A in affected trophoblasts demonstrates not only the genetic defect but also the absence of contaminating maternal tissue (which would have contributed 3. Williamson R, Eskdale J, Coleman DV, Niazi M, Loeffler FE, Modell BM. Direct gene

4. 5.

586.

may-5 be useful for first trimester

prenatal diagnosis of genetic disease. Chorionic villi derived from the trophoblast layer of the early placenta can be examined directly

1. Old JM, Ward RHT, Karagozli

F, Petrou M, Modell B, Weatherall DJ. First-trimester fetal diagnosis for haemoglobinopathies: Three cases. Lancet 1982; ii 1413-16. 2. Brambati B, Simoni G. Diagnosis of fetal trisomy 21 in first trimester. Lancet 1983; i:

LUCI TRNKA

6.

analysis of chorionic villi: a possible technique for first-trimester antenatal diagnosis of haemoglobinopathies. Lancet 1981; ii: 1125-27. Kazy Z, Rozovsky IS, Bakharev VA. Chorion biopsy in early pregnancy: a method of early prenatal diagnosis for inherited disorders. Prenatal Diagnosis 1982; 2: 39-45. Ward RHT, Modell B, Petrou M, Karagozlu F, Douratsos E. Method of sampling chorionic villi in first trimester of pregnancy under guidance of real time ultrasound Br Med J 1983; 286: 1542-44. Grebner EE, Jackson LG. Prenatal diagnosis of Tay-Sachs disease: reliability of amniotic fluid. Am J Obstet Gynecol 1979; 134: 547-50.

287 this

antibody could not be used to distinguish malignant cells from ones in this context, because epithelial cells from benign cysts and from benign fibroadenomas are found to give positive benign .

reactions.

Carcinoembryonic antigen (CEA) antibody was also applied to 32 samples (19 benign and 13 malignant), and was no more specific, since it gave positive reactions in 6 of the benign samples (all cyst fluids), and negative results in 5 of the malignant ones. of these

We thank Wellcome Diagnostics for Corvalan for the anti-CEA

Slice Number

Hexosaminidase isozyme patterns in extracts from normal and TaySachs trophoblasts as determined by PAGE.

supplying the Caantibody, and Dr J.

Nuffield Department of Pathology, John Radcliffe Hospital, Oxford

A. K. GHOSH

Laboratory of Clinical Cytology, Churchill Hospital, Oxford OX3 7LJ

A. I. SPRIGGS

Department of Pathology, Royal Berks Hospital, Reading

M. M. BODDINGTON

Department of Surgery, Royal Berks Hospital, Reading

H. B. ROSS

circles represent an extract from normal trophoblasts, and closed circles an extract from Tay-Sachs trophoblasts. Hexosaminidase activity is

Open

DIET AND THE CANCER PATIENT

expressed in arbitrary units.

clinical nutrition has dealt with aspectsl of but not yet directed specific attention to the dietary requirements and nutritional status of such patients. Undernutrition, malnutrition, and anorexia are common in malignant disease,2-5 and taste abnormalities contribute to reduced energy intake.6,7 Unsuitable or poorly prepared food may further contribute to a poor diet, in patients whose energy expenditure and resting metabolic rates are raised.8 Loss of muscle protein causes weakness and apathy, leading to further lack of interest in food. Cancer patients often have low serum albumin and vitamin concentrations whilst a dietary survey9 in advanced disease revealed the diet to be low in energy, iron, and fibre content. Chemotherapy or radiotherapy can be associated with emaciation despite apparent regression of the disease, and this is not wholly explained by nausea and vomiting. Many units (with some honourable exceptions) ignore the nutritional status of their cancer patients or give only confusing general advice (eg, "eat a balanced diet".) Patients on chemotherapy for testicular teratoma, for example, seem to experience a pronounced weight loss which may require specific management. Proposed benefitslO of nutritional support in cancer patients include lower surgical mortality, fewer postoperative wound infections, and promotion of wound healing. In advanced disease attention to appetite and nutritional status promotes psychological wellbeing, may combat cachectic symptoms, and, incidentally, may restore normal drug metabolism. Methods available for nutritional support include individual attention and professional advice about dietary requirements, food preference, and choice of food; enteral and parenteral nutritional supplements; and appetite stimulants, including alcohol and corticosteroids. Specific dietary manipulation (including minerals and trace elements) based on measured deficits might alleviate some of the symptoms these patients endure and perhaps prevent cachexia. It is surprising, in view of what has been published on

SIR,-Your series

hexosaminidase A to the sample), a point important to the general usefulness of trophoblasts for prenatal diagnosis. Elles et al, using DNA analysis, have similarly shown an absence of maternal tissue

contamination.7

We thank Dr Carl Dellabadia and Dr Martin Weisberg for help in obtaining tissue, and Deborah Mansfield for technical assistance. The work was supported by a grant from the Delaware Valley Chapter of the National TaySachs and Allied Diseases Association. Division of Medical Genetics,

Jefferson Medical College of Thomas Jefferson University, Philadelphia, Pennsylvania 19107, USA

EUGENE E. GREBNER RONALD J. WAPNER MARIE A. BARR LAIRD G. JACKSON

Cal ANTIBODY APPLIED TO CYTOLOGICAL DIAGNOSIS OF FINE NEEDLE ASPIRATES FROM BREAST LUMPS

SiR,-Following the description of the Calantibody*,2 we wished its application to smears from breast puncture material would have any practical diagnostic use. Accordingly, we made air dried smears of breast puncture aspirates-28 of them cyst fluids, chosen to show benign epithelial cells from cases of fibrocystic disease, and 28 fine needle aspirates from solid breast lumps both benign and malignant. They were all acetone-fixed, reacted with the Cal antibody, and processed by the immunoalkaline-phosphatase procedure,3 in batches which mcluded positive and negative controls. The results are shown in the table. Positive staining was usually focal and weak. Although the numbers are very small, it is clear that to determine whether

7 Elles RG, Williamson R, Niazi M, Coleman DV, Horwell D. Absence of maternal contamination of chorionic villi used for fetal-gene analysis N Engl J Med 1983; 308: 1433-35 1 Ashall F, Bramwell ME, Harris H. A new marker for human cancer cells. I: The Ca antigen and the Cal antibody. Lancet 1982; ii: 1-6 2 McGee JO’D, Woods JC, Ashall F, Bramwell ME, Harris H. A new marker for human cancer cells II Immunohistochemical detection of the Ca antigen in human tissues with the Cal antibody Lancet 1982; ii: 7-10. 3 Ghosh AK, Spriggs AI, Taylor-Papadimitriou J, Mason DY. Immunocytochemical staining of cells in pleural and peritoneal effusions with a panel of monoclonal

nutrition in

1. 2

3 4.

antibodies J Clin Pathol (in press). STAINING BY BREAST ASPIRATES

Bollag W. Vitamin A and retinoids: from nutrition to pharmacotherapy in dermatology and oncology. Lancet 1983, i: 860-63 Calman KC Nutritional support in malignant disease. Proc Nutr Soc 1978, 37: 87-93. Deitel M, Vasic V, Alexander MA. Specialised nutritional support in the cancer patient Is it worthwhile? Cancer 1978; 41: 2359-63 Nixon DW, Heymsfield SB, Cohen AE, Kutner MH, Ansley J, Lawson DH, Rudman D Protein calorie undernutrition in hospitalized cancer patients Am J Med 1980; 68: 683-90

5

Cal

on

cancer

6 7.

8

Theologides A Cancer cachexia Cancer 1979, 43: 2004-12 De Wys WD Changes in taste sensation and feeding behaviour in cancer patients: a review. J Hum Nutr 1978; 32: 447-53. Walsh TD, Bowman KB, Jackson GP. Taste changes in advanced cancer patients. Prac Nutr Soc 1982; 41 (3): 100A (abstr) Warnold I, Lindholm K, Schersten T. Energy balance and body composition in cancer

patients Cancer Res 1978; 38: 1801-07 TD, Bowman KB, Jackson GP. Dietary intake of advanced cancer patients. Hum Nutr Appl Nutr 1983; 37A: 41-45. 10 Copeland EM III, Dudrick SJ The importance of parenteral nurition as an adjunct to cancer treatment. In: Johnston IDA, ed Advances in parenteral nutrition. Lancaster: MTP Press, 1978. 9 Walsh