Clinical and Experimental Dermatology (1976) i , 243.
Whole body monitoring and other studies of zinc-65 metabolism in patients with dermatological diseases
T. HAWKINS,* JANET M. MARKS, VALERIE M. PLUMMERt AND MALCOLM W. GREAVESt * Regional Medical Physics Department, Newcastle General Hospital, and University Department of Dermatology, Royal Victoria Infirmary, Newcastle-upon-Tyne Accepted for publication 4 May 1976
Siunmary The retention of-an oral dose of **'Zn was measured in patients with skin disease over a period of 231 days using a whole body monitor. The retention was compared with available data on healthy subjects. No significant differences were observed for the group as a whole. In a small clinical subgroup with venous leg ulcers, a lower retention and a shorter biological half life of ^^2n were found. Faecal and urinary loss of ^^Zn were measured over the first 7 days, and indirectly confirmed the retention values obtained by whole body counting. Whole blood and plasma *'-^Zn concentrations were studied up to 192 days. No significant differences were observed when compared with other disease groups. The activity profiles of some patients appeared to confirm the liver as the organ of early preferential uptake. A close similarity of the metabolic behaviour of zinc and iron was observed. The minimum daily requirements of zinc to maintain body stores is assessed as 24-4-2 mg.
The observation that the rash and other clinical signs of acrodermatitis enteropathica respond dramatically to treatment with zinc (Moynahan, 1974) has revived an interest in zinc and its relation to the skin. There has in the past been much work on zinc and its distribution in the body (Prasad, 1966) but relatively few studies have been made on the skin itself or on patients with skin diseases. Serum (or plasma) zinc concentrations have been reported to be abnormally low in patients with a number of dermatological conditions (Greaves & Boyde, 1967; Withers et al, 1968; Halsted & Smith, 1970; Sergeant, Galloway & Gueri, 1970; Hallbrook & Lanner, 1972; Oon et al, 1974)- Studies in some of these patients have shown that skin zinc content correlates poorly with serum zinc concentration (Oon et al, 1974) and this suggests that serum zinc is a t Present address: Institute of Dermatology, Lisle Street, Leicester Square, London WC2. Requests for reprints to: T. Hawkins, Regional Medical Physics Department, Newcastle General Hospital, Newcastle-upon-Tyne NE4 6BE. 243
244
T- Hawkins et al.
poor index of the zinc status of the body as a whole in these patients. Patients with normal serum zinc concentrations are usually assumed not to be zinc deficient and thus are likely to be excluded from trials of treatment with zinc from which they might benefit: zinc has previously been advocated for certain skin diseases including psoriasis, leg ulcers and the skin lesions of leprosy (Voorhees et al, 1969; Husain, 1969; Hallbrook & Lanner, 1972; Oon et al, 1974). It is equally possible that patients reported to have low serum concentrations of zinc are not zinc deficient and that the low concentrations in fact results from an altered distribution of zinc within the body. This would be comparable with the metabolic hypoferraemia of skin disease where treatment with iron is neither effective nor necessary (Marks & Shuster, 1968). Furthermore, hypoferraemia is one of the systemic effects of skin disease (Shuster, 1967) which is not dependent upon the nature of the dermatological condition. The object of our present study was to investigate patients with various skin diseases regardless of their serum zinc concentration and to compare them with healthy subjects reported in the literature in an attempt to identify an abnormality of zinc metabolism. We have measured total body retention of an oral dose of radioactive *'^Zn using a whole body monitor (WBM) over a period of 231 days. Faecal and urinary loss, distribution between blood cells and plasma and whole body distribution of the isotope were also measured. Methods Patients. Nine patients admitted to hospital with various dermatological conditions were selected by their willingness to take part in the investigation, details of which were explained to them. All remained in hospital for the first 2 weeks but in the majority the studies were continued on an out-patient basis afterwards. The patients were given an ordinary hospital diet estimated to contain 10-15 nig zinc per day, while they were in hospital and were not given special instructions about diet when they went home. Clinical details and serum zinc concentrations are shown in Table i. Procedure. All measurements were made over the i i i MeV y-ray photopeak of '^^Zn. Zinc-65 chloride in o-i N hydrochloric acid (Sp.A. 058 mg/mCi) was used. The oral doses of 16-25 /'Ci of ^^Zn were each prepared in a smallflask,made up to 20 ml with water and given with washings directly to the patient who had fasted overnight. Residual activity in the flask C
Whole body monitoring and other studies of zinc-65 metabolism in patients with dermatological diseases
T. HAWKINS,* JANET M. MARKS, VALERIE M. PLUMMERt AND MALCOLM W. GREAVESt * Regional Medical Physics Department, Newcastle General Hospital, and University Department of Dermatology, Royal Victoria Infirmary, Newcastle-upon-Tyne Accepted for publication 4 May 1976
Siunmary The retention of-an oral dose of **'Zn was measured in patients with skin disease over a period of 231 days using a whole body monitor. The retention was compared with available data on healthy subjects. No significant differences were observed for the group as a whole. In a small clinical subgroup with venous leg ulcers, a lower retention and a shorter biological half life of ^^2n were found. Faecal and urinary loss of ^^Zn were measured over the first 7 days, and indirectly confirmed the retention values obtained by whole body counting. Whole blood and plasma *'-^Zn concentrations were studied up to 192 days. No significant differences were observed when compared with other disease groups. The activity profiles of some patients appeared to confirm the liver as the organ of early preferential uptake. A close similarity of the metabolic behaviour of zinc and iron was observed. The minimum daily requirements of zinc to maintain body stores is assessed as 24-4-2 mg.
The observation that the rash and other clinical signs of acrodermatitis enteropathica respond dramatically to treatment with zinc (Moynahan, 1974) has revived an interest in zinc and its relation to the skin. There has in the past been much work on zinc and its distribution in the body (Prasad, 1966) but relatively few studies have been made on the skin itself or on patients with skin diseases. Serum (or plasma) zinc concentrations have been reported to be abnormally low in patients with a number of dermatological conditions (Greaves & Boyde, 1967; Withers et al, 1968; Halsted & Smith, 1970; Sergeant, Galloway & Gueri, 1970; Hallbrook & Lanner, 1972; Oon et al, 1974)- Studies in some of these patients have shown that skin zinc content correlates poorly with serum zinc concentration (Oon et al, 1974) and this suggests that serum zinc is a t Present address: Institute of Dermatology, Lisle Street, Leicester Square, London WC2. Requests for reprints to: T. Hawkins, Regional Medical Physics Department, Newcastle General Hospital, Newcastle-upon-Tyne NE4 6BE. 243
244
T- Hawkins et al.
poor index of the zinc status of the body as a whole in these patients. Patients with normal serum zinc concentrations are usually assumed not to be zinc deficient and thus are likely to be excluded from trials of treatment with zinc from which they might benefit: zinc has previously been advocated for certain skin diseases including psoriasis, leg ulcers and the skin lesions of leprosy (Voorhees et al, 1969; Husain, 1969; Hallbrook & Lanner, 1972; Oon et al, 1974). It is equally possible that patients reported to have low serum concentrations of zinc are not zinc deficient and that the low concentrations in fact results from an altered distribution of zinc within the body. This would be comparable with the metabolic hypoferraemia of skin disease where treatment with iron is neither effective nor necessary (Marks & Shuster, 1968). Furthermore, hypoferraemia is one of the systemic effects of skin disease (Shuster, 1967) which is not dependent upon the nature of the dermatological condition. The object of our present study was to investigate patients with various skin diseases regardless of their serum zinc concentration and to compare them with healthy subjects reported in the literature in an attempt to identify an abnormality of zinc metabolism. We have measured total body retention of an oral dose of radioactive *'^Zn using a whole body monitor (WBM) over a period of 231 days. Faecal and urinary loss, distribution between blood cells and plasma and whole body distribution of the isotope were also measured. Methods Patients. Nine patients admitted to hospital with various dermatological conditions were selected by their willingness to take part in the investigation, details of which were explained to them. All remained in hospital for the first 2 weeks but in the majority the studies were continued on an out-patient basis afterwards. The patients were given an ordinary hospital diet estimated to contain 10-15 nig zinc per day, while they were in hospital and were not given special instructions about diet when they went home. Clinical details and serum zinc concentrations are shown in Table i. Procedure. All measurements were made over the i i i MeV y-ray photopeak of '^^Zn. Zinc-65 chloride in o-i N hydrochloric acid (Sp.A. 058 mg/mCi) was used. The oral doses of 16-25 /'Ci of ^^Zn were each prepared in a smallflask,made up to 20 ml with water and given with washings directly to the patient who had fasted overnight. Residual activity in the flask C
