Cryo-EM structure of the diapause chaperone artemin.

The protein artemin acts as both an RNA and protein chaperone and constitutes over 10% of all protein in Artemia cysts during diapause. However, its mechanistic details remain elusive since no high-resolution structure of artemin exists. Here we report the full-length structure of artemin at 2.04 Å resolution. The cryo-EM map contains density for an intramolecular disulfide bond between Cys22-Cys61 and resolves the entire C-terminus extending into the core of the assembled protein cage but in a different configuration than previously hypothesized with molecular modeling. We also provide data supporting the role of C-terminal helix F towards stabilizing the dimer form that is believed to be important for its chaperoning activity. We were able to destabilize this effect by placing a tag at the C-terminus to fully pack the internal cavity and cause limited steric hindrance.

Timing of surgery in relation to the menstrual cycle in premenopausal women with operable breast cancer.

Recent studies have suggested that the timing of surgery in relation to the menstrual cycle might influence survival of premenopausal women with operable breast cancer. The data of 96 premenopausal patients who underwent primary surgery for operable breast carcinoma between 1975 and 1988 were analysed. At 10 years, disease-free and overall survival rates of patients whose initial surgery was 1-12 days after the starting date of the last menstrual period (follicular phase) were significantly poorer compared with survival of those who underwent operation more than 12 days after the last menstruation (luteal phase) (disease-free survival rate 40 versus 72 per cent, P = 0.002; overall survival rate 40 versus 79 per cent, P = 0.001). These differences in survival remained significant in a second analysis based on the menstrual phase at the time of both initial and definitive operation. Menstrual phase had the greatest impact on the survival of patients with positive axillary nodes (P = 0.009). Prospective studies are required to elucidate the relationship between the timing of all surgical procedures during the menstrual cycle and survival.

Timing of surgery influences survival in receptor-negative as well as receptor-positive breast cancer.

Analysis of oestrogen and progesterone receptor (ER, PR) status was interpreted in relation to menstrual phase at the time of surgery and survival in 84 women diagnosed with breast cancer between 1975 and 1988. We showed previously (Br J Surgery 1994, 81, 217-220) that long-term survival was significantly poorer when surgery was performed during the follicular phase of the menstrual cycle compared to luteal phase; we now demonstrate that this effect on survival is at least as important in receptor-negative as receptor-positive patients. At 10 years, overall survival (OS) of ER-positive patients who had their biopsy during the follicular phase was significantly poorer than for those whose biopsy was performed during the luteal phase of their menstrual cycle (52 versus 88%, P = 0.02). OS for the ER-negative follicular phase group was also significantly poorer than that for the ER-negative luteal phase group (33 versus 76%, P = 0.009). The OS difference between the PR-positive follicular phase group and PR-positive luteal phase group was of borderline significance (60 versus 87%, P = 0.06), while the difference in OS between the PR-negative follicular phase group and that of the PR-negative luteal phase group was highly significant (13 versus 76%, P = 0.001). Disease-free survival for these groups followed a similar trend. The survival differences in receptor-negative women suggest that hormonal fluctuations at the time of surgery may have complex indirect effects on tumour growth and metastasis. The mechanism, if indeed independent of the tumour steroid receptors, could also apply in other cancers.

Deep pelvic abscesses: transrectal drainage with radiologic guidance.

Transrectal catheter drainage was performed under radiologic guidance in eight patients with deep pelvic abscesses during a 7-month period. One patient underwent two procedures. In five patients, the abscess could not be palpated at rectal examination. Seven procedures were performed with fluoroscopic guidance. Transrectal ultrasound was performed in conjunction with fluoroscopy for two procedures. Medium to large (8-14-F) locking catheters were used in seven procedures, and small (5-F) nonlocking pigtail catheters were used in two. The catheter was left in place for 3 days or less in all but one patient, in whom the catheter was left in place for 20 days. Five abscesses were drained through the anterior or anterolateral rectal wall and four, including one repeat drainage, through the posterior rectal wall. No complications occurred as a direct result of transrectal drainage. Successful initial drainage was established with clinical improvement in all cases. Two patients eventually required surgery, one for continued bleeding into an infected hematoma and one for abscess recurrence after tube dislodgment. Transrectal drainage performed with radiologic guidance is a safe, feasible procedure; is well tolerated by patients; and is relatively easy to perform with the techniques described.

Primary gastric T-cell lymphoma of suppressor-cytotoxic (CD8+) phenotype: discordant expression of T-cell receptor subunit beta F1, CD7, and CD3 antigens.

Primary gastric T-cell lymphomas are rare neoplasms, and all but one of the previously phenotyped cases have shown a helper-inducer phenotype. The present case is the second reported case of a primary gastric T-cell lymphoma of suppressor-cytotoxic phenotype. The tumor histology was similar to that described in some forms of node-based peripheral T-cell lymphomas. Phenotypic analysis revealed low expression of pan-T marker CD7, reduced expression of CD3, but higher density and frequency of expression of CD8 antigens that could be predicted on the basis of the pan-T markers. Natural killer cell (NK) related markers CD16, HNK-1 and NKH-1 were not expressed by the neoplastic cells. T-cell receptor (TCR) beta subunit expression was detected on fewer cells than would have been predicted on the basis of CD3 and CD8 expression, and TCR delta chain expression was undetectable.

Chronic ileal obstruction in adults due to peri-ileal vitelline vascular remnants.

Two young adults had distal ileal obstruction at sites where a fold of mesentery extended from its posterior leaf to the antimesenteric border of the bowel. No Meckel's diverticulum or mesoumbilical band was present in either case. Clinical, gross and microscopic findings suggested that the mesenteric fold represented a remnant of vitelline vessel that persisted in the peri-ileal portion of its course. Chronic ileal obstruction was apparently due to disordered peristalsis caused by the fold tethering the adjoining posterior bowel wall. In one patient, a chronic ulcer at the site of obstruction was interpreted as being an additional complication of the congenital lesion.