Reproduction in the Mediterranean endemic gorgonian Spinimuricea klavereni (Anthozoa,Octocorallia, Plexauridae)

Spinimuricea klavereni is a Mediterranean endemic gorgonian that is rarely encountered, probably because it typically occurs at depths below 50 m. It is exceptionally common in the northern Marmara Sea, with an unusually shallow upper depth limit of ~20 m. The reproductive biology of this species was studied during a one year period off Büyükada, in the northeastern Marmara Sea. Spinimuricea klavereni is a gonochoric broadcast spawner with an almost even sex ratio. Colonies were ~15 cm in height at first reproduction. Gametogenesis was continuous, characterized by high male and female fecundities year‐round. Oocytes and sperm sacs of all developmental stages were found throughout the year, with small‐sized oocytes and sperm sacs dominant throughout the year. The reproduction of S. klavereni did not seem to exhibit any marked seasonal pattern, unlike most other studied Mediterranean octocorals. Modest variation in gamete output was probably related to slight alterations in food availability and temperature. The non‐seasonal reproductive pattern we observed may be related to the low intra‐annual variation in temperature in the Marmara Sea, and the fact that the mesotrophic‐eutrophic level of productivity in the Marmara Sea can support the energetic requirements of continuous gametogenesis in this gorgonian. Whether these patterns are local adaptations or intrinsic characteristics for this Mediterranean endemic species remains to be studied.     

Rapid kinetics of lysis in human natural cell-mediated cytotoxicity: Some implications

The entire lytic process of natural cell-mediated cytotoxicity against sensitive target cells can occur rapidly, within minutes. This was demonstrated by ⁵¹chromium release and in single-cell assays. At the cellular level, most of the target cell lysis occurred within 15–30 min after binding to effector cells. The enriched natural killer cell subpopulation of lymphocytes obtained by Percoll density gradient centrifugation (containing >70% large granular lymphocytes (LGL)) was the most rapidly lytic population by ⁵¹chromium release. However, in the single-cell assay, the rate of lysis of bound target cells was quite similar for the LGL-enriched effector subpopulation and the higher density subpopulation of effector cells recognized previously. Both the light and dense effector cells contained similar numbers of target binding cells. Therefore, that the light subpopulation effected lysis more rapidly and to a greater extent than the dense subpopulation suggested that the low-density effector cells probably recycled more rapidly than those of higher density. This was corroborated by the finding that when conjugates were formed at 29 °C for the single-cell assay, a significant number of dead unconjugated targets could be observed only on the slides made with the LGL-enriched effector cells but not on those made with dense effector cell. Lysis continued to increase in the chromium-release assay probably because of recycling, recruitment, and/or heterogeneity of the effector cells, and/or because of heterogeneity or delayed death of the target cells.     

A galactoglucomannan from extracellular polysaccharides of suspension-cultured cells of Nicotiana tabacum

A polysaccharide containing d-xylose, l-arabinose, d-mannose, d-galactose and d-glucose residues in the molar ratio of 0.07:0.16:1.     

Structural investigation of the arabinoxyloglucan from Nicotiana tabacum

The structure of tobacco arabinoxyloglucan has been further studied by methylation analysis, by ¹H-, and ¹³C-n.m.r., and by fd. mass spectrometry, after complete digestion by cellulase. The results showed the polysaccharide molecule to be composed of two parts; a hexasaccharide component (AraXyl₂Glc₃, 1) and an unsubstituted (1→4)-β-d-glucan region (4-O-linked glucosyl residues) in the molar ratio of ～ 1:2. Some heterogeneities of this structure in the arabinofuranosyl sub-group were also found.     

Triptolide inhibits CD133+/CD44+ colon cancer stem cell growth and migration through triggering apoptosis and represses epithelial-mesenchymal transition via downregulating expressions of snail,slug, and twist

High recurrence and metastatic behavior patterns are the most important reasons for the failure of treatment strategies in patients with colon cancer. Cancer stem cells (CSCs), which are considered root of cancer, are thought to be associated with therapy resistance, relapse, and metastasis, and, therefore, targeting CSCs rather than the bulk population may be an effective approach. In cancer studies, there is an increasing interest in close friendship between epithelial-mesenchymal transition (EMT) and CSCs. Triptolide (TPL) isolated from Chinese herb Tripterygium wilfordii has important effects on the prevention of migration and metastasis as well as cytotoxic effect against cancer cells. The potential lethal efficacy of TPL on CSCs that is highly resistant to the drug is an unsolved mystery. Fundamentally, the present study basically aims to find answers to two questions: (a) is it possible to target colon CSCs with TPL? and (b) what are the mechanisms underlying TPL's potential to eliminate CSCs? Cytotoxic effects of TPL on CSCs were evaluated by WST-1 and Muse count and viability assays. Apoptosis assay and cell-cycle analysis were performed to investigate the inhibitory effect of TPL. Moreover, the effects of TPL on spheroid formation capacity, migration, and EMT processes, which are associated with CSC phenotype, were also investigated. The results revealed that TPL triggered cell death and apoptosis and altered cell cycle distribution. Moreover, TPL significantly reduced the snail slug and twist expressions associated with EMT. TPL has been shown to be effective in colon CSCs by in vitro experiments, and it might be a highly effective agent against colon cancer has been implicated in need of supporting in vivo and clinical studies.     

Further Careers of Young British Doctors

After surveys in 1961 and 1966, further questionnaires were sent in 1969 to those who had responded in 1966. These showed that wastage due to emigration and unemployment of married women doctors was nearly 20%. Compared with 49% of all qualified for three to four years in 1966, 73% had definitely decided on their future career seven to eight years after qualifying in the 1969 survey, the choice tending to be for specialties less popular among more junior doctors. Responsibility for patient care seemed not to be related directly to seniority or to performance in medical school examinations.