Prolonged endometrial stimulation associated with oestradiol implants.

OBJECTIVE--To provide information on endometrial stimulation after discontinuation of treatment with oestradiol implants. DESIGN--Long term follow up of withdrawal bleeding patterns in women taking progestogens cyclically every month after oestradiol implant treatment was ended. SETTING--Specialist menopause clinic. SUBJECTS--10 Postmenopausal patients (at least 12 months'' amenorrhoea after the last spontaneous period) who were treated with oestradiol implants for typical symptoms of oestrogen deficiency. The oestradiol dose was 50 mg, reimplantation occurring roughly every six months. Patients subsequently either needed to discontinue the hormone treatment for medical reasons or expressed a desire to stop treatment. MAIN OUTCOME MEASURE--Duration of endometrial stimulation--defined as the presence of withdrawal bleeding in response to progestogen given cyclically--after insertion of the last oestradiol implant. RESULTS--Four patients eventually stopped bleeding, their mean duration of bleeding being 35 months (range 27-43 months). One patient required hysterectomy 26 months after the last implantation because of persistent irregular bleeding despite treatment with high doses of progestogen. Three patients bled for 22, 30, and 36 months and then restarted oestrogen treatment because symptoms returned. The last two patients subsequently continued to bleed 12 and 21 months after the last implantation. CONCLUSIONS--The duration of endometrial stimulation after implantation can be prolonged, up to 43 months. Insertion of oestradiol implants can carry a long term commitment to the cyclical administration of progestogen and regular withdrawal bleeding if endometrial hyperplasia and carcinoma are to be avoided.     

Involvement of Protein and Ribonucleic Acid in the Association of Deoxyribonucleic Acid with Other Cell Components of Escherichia coli

Cells of Escherichia coli were labeled with precursors of ribonucleic acid (RNA), deoxyribonucleic acid (DNA), and protein, lysed with detergent, and examined by starch-block electrophoresis and CsCl density gradient centrifugation. A large amount of the DNA was seen to remain at positions of low electrophoretic mobility and light density along with tryptophan and arginine-containing proteins and some RNA. Addition of labeled, phenol-extracted DNA to unlabeled cells prior to lysis and electrophoresis showed that only a small amount of the DNA became associated during or after lysis. Sonic treatment of a lysate removed most of the DNA to a position of electrophoretic mobility and density similar to that of free DNA, whereas pronase and ribonuclease released only a part of the DNA. We concluded that binding of DNA to cell membranes or other cell components occurs in the cell prior to lysis and involves protein and probably a specific type of RNA.