Restriction of the rat-specific RNS sequences of Ki-MSV to the nucleus of dibutyryl cyclic AMP-treated K-A31 cells

The treatment of oncogenically transformed cells in culture, with dibutyryl cyclic AMP (cAMP) has, in many cases, resulted in a general phenotypic change towards the normal state. A virus-specific gene product(s) is responsible for the transformation of cells by sarcoma viruses and it has been suggested that the src gene product may act through the alteration of cAMP levels. With these premises we have studied the effects of dibutyryl cAMP on cell growth and virus genome expression in a Kirsten sarcoma virus-transformed mouse cell line. Our results suggest that certain virus-specific RNA sequences are restricted to the nucleus of these cells after several days of growth in medium containing dibutyryl cAMP and that these sequences appear to be those coding for the sarcoma information.     

Advantages of adding a course of tetracycline to single dose ampicillin and probenecid in the treatment of gonorrhoea.

Chlamydia trachomatis was reisolated from 11 of 12 men with gonorrhoea who had initially yielded chlamydiae and who had been treated with ampicillin and probenecid (AMP) only, but from none of five such men treated with ampicillin and probenecid followed by tetracycline (AMPT). These results correlated with the absence of postgonococcal urethritis (PGU) in the group treated with AMPT. C trachomatis was isolated or reisolated from 20 of 25 women after treatment with AMP, compared with none of 14 women treated with AMPT. We recommend the addition of a course of tetracycline to the routine single dose treatment for gonorrhoea in men and women.     

Central hypothyroidism.

Central hypothyroidism is an uncommon condition characterized by insufficient thyroid gland stimulation by TSH, owing to hypothalamic and/or pituitary dysfunction. It is rarely isolated but more often occurs in conjunction with deficiencies of other pituitary hormones, as well as with neurologic symptoms and signs owing to hypothalamic/pituitary lesions. The diagnosis rests on documentation of clinical and biochemical hypothyroidism with an inappropriately low or nonelevated serum TSH level. Recent studies suggest that the temporal pattern of TSH secretion, as well as TSH structure, is altered in central hypothyroidism, providing a mechanism for the induction of the hypothyroid state in this condition.     

Pure α-subunit producing tumor derived from a thyrotropic tumor: Impaired regulation of a-subunit and its mRNA by thyroid hormone

We have recently described a mouse pituitary tumor line which produces only the α-subunit of the glycoprotein hormones. This tumor line may be a useful animal model to study autonomous pituitary tumors which secrete only α-subunit. Our pure α-subunit producing tumor was derived from a thyrotropic tumor which secreted intact TSH as well as free α-subunit. Our current studies compare the regulation of α-subunit biosynthesis in a conventional thyrotropic tumor and the α-subunit producing tumor. Thyroxine or triiodothyronine administration to mice bearing the a-subunit producing tumor resulted in no change in plasma α-subunit concentration, and a 10–19% reduction in tumor α-subunit mRNA concentration that was not statistically significant. In contrast, thyroxine administration to mice bearing the thyrotropic tumor resulted in an 81% reduction in plasma α-subunit concentration, and a 75% reduction in tumor α-subunit mRNA concentration (P < 0.01). Other studies using a cDNA specific for thyrotropin-β (TSHβ) failed to detect TSHβ mRNA in the α-subunit producing tumor, while TSHβ mRNA was easily detected in the conventional thyrotropic tumor. We conclude that during the development of the a-subunit producing tumor from a thyrotropic tumor, loss of TSHβ mRNA was also associated with an impaired capacity for thyroid hormone to decrease concentrations of α-subunit mRNA.     

Endophthalmitis due to caterpillar setae: surgical removal and electron microscopic appearances of the setae.

A case of endophthalmitis due to caterpillar setae was, for the first time, successfully treated by surgical removal of the setae. The procedure was facilitated by the use of sodium hyaluronidate. Scanning and transmission electron microscopy of the setae showed evidence of enzymatic degradation of the shaft and burial of the spines in exudate.