Expression of human alpha-globin genes in hybrid mouse erythroleukaemia cells depends on differentiated state of human donor cell

We have developed a system which can be used to study the mechanisms that may govern the expression of human alpha-globin genes in human erythroid and non-erythroid haematopoietic cells. Human chromosome 16, which has been shown to bear the human alpha-globin genes, is introduced by cell fusion into mouse erythroleukemia (MEL) cells to generate continuously proliferating cell lines that retain permanently the human alpha-globin genes. We have shown that hybrid diploid MEL cells with human alpha-globin genes from erythroid donor cells express these genes fully through globin chain synthesis, while hybrid diploid MEL cells containing human alpha-globin genes from non-erythroid human haematopoietic donor cells contain very low levels of human alpha-globin mRNA and no detectable human alpha-globin chains. The levels of human alpha-globin mRNA in these hybrid cells were found to depend on factors present in the MEL recipient cell as well as on the differentiated state of the human donor cell, suggesting that this system may be suitable for characterisation of mechanisms governing haematopoietic differentiation in man.

Studies on the antidiuretic effect of cyclophosphamide: vasopressin release and sodium excretion

To elucidate the mechanism of cyclophosphamide (CTX)-induced antidiuresis, plasma and urine volume as well as serum electrolytes, creatinine, osmolality, and appropriate hormones were monitored serially during 19 courses of chemotherapy. In spite of plasma hypotonicity and urinary hypertonicity, the plasma vasopressin concentrations were unaltered. Intravenous isotonic hydration did not prevent water retention, but did not lead to plasma hypotonicity, and compensated for modest urinary sodium losses. Furosemide diuresis did not prevent the development of hyponatremia in patients receiving hypotonic hydration. The results indicate that the origin of this self-limited syndrome is a direct effect of CTX on the renal tubule, permitting increased water reabsorption and sodium loss. The likelihood that water and salt imbalance will develop after CTX administration can be reduced by vigorous isotonic hydration, and pharmacological diuresis.

[Classification of follicular cysts: epidermal cysts including Günther sebocystomatosis, steatocystoma multiplex and trichilemmal cysts]

The clinical and histopathological nomenclature of various follicle-derived cysts is confusing. A uniform terminology, based on histopathological criteria is proposed. Cysts may develop from vellus follicles, sebaceous follicles, and terminal hair follicles. The various sections from each follicle may give rise to various types of cysts: 1. the infundibulum to epidermal cysts (e.g. epidermal cysts, comedones, milia, and scrotal cysts); 2. the sebaceous ducts and sebaceous acini to steatocystoma multiplex; 3. the infraglandular portion of the infrainfundibulum to trichilemmal cysts (atheromas). A clinical variant of epidermal cysts, the scrotal cysts, at times incorrectly called sebocystomatosis Günther, is described in 10 patients. For all types of cysts clinical and histopathological guidelines are offered.

Hypothalamic-pituitary dysfunction following CNS prophylaxis in acute lymphocytic leukemia: correlation with CT scan abnormalities

In an attempt to identify possible adverse effects of CNS prophylaxis (cranial radiation and intrathecal chemotherapy), we examined hypothalamic-pituitary function in 23 patients with acute lymphocytic leukemia (ALL). Of 18 patients who had received both cranial radiation and intrathecal chemotherapy, nine had abnormally low growth hormone responses to insulin-induced hypoglycemia (less than 7.0 ng/ml). Seven of the nine patients with abnormally low growth hormone responses also manifested ventricular dilatation on computed tomography (CT) brain scans, whereas only one of the nine patients with normal growth hormone responses demonstrated this CT scan finding (P = 0.015). The remaining patients, who had not received cranial radiation, had normal growth hormone responses and normal CT scans. There is significant correlation between ventricular dilatation on CT and abnormally low peak growth hormone responses following CNS prophylaxis in ALL.

[The acquired digital fibrokeratoma]

A case of acquired digital fibrokeratoma is presented. The asymptomatic cylindrical tumor preferably occurs during the third to sixth decade of life and affects mainly the fingers. Histologically one finds a cylindriform connective tissue proliferation surrounded by an akantholytic band of epidermis with papillomatous changes and hyperkeratosis. For differential diagnosis rudimentary supernumerary digit, cutaneous horn and granuloma pyogenicum are to be considered. Therapy consists of excision of this benign tumor of hitherto unknown origin.