Concise stereocontrolled routes to fumagillol,fumagillin, and TNP-470

A concise, diastereoselective synthesis of (+/-)-fumagillol (3) and formal, enantioselective syntheses of the potent angiogenesis inhibitors fumagillin (1) and TNP-470 (2) are reported. The origin of asymmetry is a highly diastereoselective Diels-Alder reaction using a diene with a chiral oxazolidinone auxiliary. The stereochemical course of a key conjugate addition reaction is controlled by the cup-shaped architecture of a cis-fused bicyclic enal. Other key steps include a facile hetero-Claisen rearrangement and a site-selective Sharpless epoxidation.     

Upstream movements of benthic macroinvertebrates in two different types of fishways in southwestern Germany

Upstream movements and migrations of benthic macroinvertebrates are an important component of running water dynamics. Many lotic organisms perform upstream movements at some stage in their life-cycle. We investigated whether a boulder ramp and a concrete bypass fishway on two streams in Baden-Württemberg, Germany, are successfully used by benthic invertebrates to reach upstream areas. We compared macroinvertebrate distribution at sites upstream and downstream of the fishways, rated the fishways according to their constructional features and conducted migration experiments with marked Gammaridae in the passages. The number of taxa and densities of macroinvertebrates did not significantly differ between upstream and downstream sites in both rivers. Constructional features and the results of the mark-recapture experiments indicated that the boulder ramp allows upstream migrations in principal, whereas the bypass is more difficult for macroinvertebrates to ascend. Both fishways immediately exit into an impoundment, which is a potential barrier for migrating invertebrates. High average current velocities, lack of lenitic banks and sheltered interstices, as well as problems caused by the operation of a power plant are factors explaining why the Enz River bypass is only marginally functional for invertebrates. The investigation concludes that in constructing fishways suitable for upstream movements of lotic invertebrates, more attention should be paid to their specific requirements.     

Differences in late fetal death rates in association with determinants of small for gestational age fetuses: population based cohort study

Objective: To examine differences in late fetal death rates in association with determinants of small for gestational age fetuses. Design: Population based cohort study. Subjects: 1 026 249 pregnancies without congenital malformations. Setting: Sweden 1983-92. Main outcome measure: Late fetal death rate. Results: Depending on underlying determinants late fetal death rates were greatly increased in extremely small for gestational age fetuses (range 16 to 45 per 1000) compared with non-small for gestational age fetuses (1.4 to 4.6). In extremely small for gestational age fetuses late fetal death rates were increased from 31 per 1000 in mothers aged less than 35 years to 45 per 1000 in older mothers, and from 22 per 1000 in women <155 cm in height to 33 per 1000 in women ⩾175 cm tall. Late fetal death rates were also higher in extremely small for gestational age fetuses in singleton compared with twin pregnancies and in non-hypertensive pregnancies compared with pregnancies complicated by severe pre-eclampsia or other hypertensive disorders. Slightly higher late fetal death rates were observed in nulliparous compared with parous women and in non-smokers compared with smokers.Conclusions: Although the risk of late fetal death is greatly increased in fetuses that are extremely small for gestational age the risk is strongly modified by underlying determinants—for example, there is a lower risk of late fetal death in a small for gestational age fetus if the mother is of short stature, has a twin pregnancy, or has hypertension.

Key messages

• Small for gestational age fetuses are at increased risk of late fetal death regardless of the underlying determinants
• The effect of birthweight ratio on risk of late fetal death is modified by underlying determinants, except maternal age
• Regardless of birthweight ratio the rates of late fetal death are higher among women aged 35 years or older compared with younger women
• In pregnancies of extremely small for gestational age fetuses lower rates of late fetal death are associated with a maternal age of less than 35 years, short maternal stature, multiple births, and hypertensive disorders
• In pregnancies with non-malformed fetuses late fetal death rates are increased in smokers, in multiple births, and in women with severe pre-eclampsia.

     

Plant regeneration from mesophyll protoplasts in Isatis indigotica

Protoplasts of an accession of Isatis indigotica Fort. were isolated from mesophyll tissue by enzymatic digestion and cultured using a feeder cell system. Shoot regeneration efficiency was 100% via organogenesis among 627 isolated calluses within 30–37 days. Among these shoot initiating calluses, 162 (22.6%) developed normal shoots with multiple (2–5) shoots per callus. The remaining calluses developed only vitreous shoots. High concentration (5 μM) of indole-3-butyric acid had a positive effect on rooting compared to low concentration (0.5 μM) of indole-3-butyric acid and α-naphthalene-acetic acid. The average rooting efficiency of regenerated shoots of two experiments was higher on LS medium with 5 μM indole-3-butyric acid than on LS medium without growth regulators. Twenty-nine plantlets, with 2–3 expanded leaves and roots were potted in soil and 22 developed normally to maturity in the glasshouse. This revised version was published online in June 2006 with corrections to the Cover Date.