[2+2+1] cyclization of allenes.

The [2+2+1] cyclization of an alkyne, an alkene and carbon monoxide, i.e., the Pauson-Khand reaction, is one of the most powerful tools for constructing a five-membered ring. In place of the alkene or alkyne part, the use of an allene functionality has proven to make this reaction more valuable for organic synthesis. This review focuses on the origin and progress of the allenic [2+2+1] cyclocarbonylation, including the chirality transfer of the allene and its synthetic applications.

First measurement of the neutron beta asymmetry with ultracold neutrons.

We report the first measurement of an angular correlation parameter in neutron beta decay using polarized ultracold neutrons (UCN). We utilize UCN with energies below about 200 neV, which we guide and store for approximately 30 s in a Cu decay volume. The interaction of the neutron magnetic dipole moment with a static 7 T field external to the decay volume provides a 420 neV potential energy barrier to the spin state parallel to the field, polarizing the UCN before they pass through an adiabatic fast passage spin flipper and enter a decay volume, situated within a 1 T field in a 2x2pi solenoidal spectrometer. We determine a value for the beta-asymmetry parameter A_{0}=-0.1138+/-0.0046+/-0.0021.

Characterization of the mechanism of zidovudine uptake by rat conditionally immortalized syncytiotrophoblast cell line TR-TBT.

PURPOSE: To characterize the uptake mechanism of zidovudine (AZT), a nucleoside reverse transcriptase inhibitor, in syncytiotrophoblast cells using the TR-TBT 18d-1 cell line previously established by our group. MATERIALS AND METHODS: The effects of several transporter inhibitors on the initial and steady-state apical uptake of AZT by TR-TBT 18d-1 were characterized, in order to identify the transporter(s) involved. RESULTS: Initial uptake of AZT was sodium-independent and saturable; the K(m) value was about 16 microM. Nitrobenzylthioinosine (NBMPR), probenecid and cimetidine each had little effect on the saturable AZT uptake, indicating that well characterized transporters, such as organic anion transporters (OATs and OATPs), organic cation transporters (OCTs) and equilibrative nucleoside transporters (ENTs), are not involved. However, thymidine and 2'-deoxyuridine strongly inhibited AZT uptake. These results suggest that an unidentified nucleoside uptake transporter is responsible for the uptake of AZT. Cyclosporin A, Ko143 and probenecid had little effect on AZT accumulation by TR-TBT 18d-1 cells, suggesting that transporter-mediated efflux of AZT is not substantial. CONCLUSION: Our results indicate that saturable AZT uptake into TR-TBT 18d-1 is mediated by a so-far-unidentified transporter.

Enantioselective total synthesis of a potent antitumor antibiotic, fredericamycin A.

The asymmetric total synthesis of both enantiomers of the potent antitumor antibiotic fredericamycin A (1) is detailed based on the protocol for the construction of its peri-hydroxy polyaromatic skeleton bearing the chirality at the spiro carbon via a strong base-induced cycloaddition of suitably substituted homophthalic anhydrides (AB-ring unit) with an optically active CDEF-ring unit. Particular attention has been given to the novel synthesis of the optically active spiro carbon center by a stereospecific rearrangement of optically active benzofuzed-trans-epoxy acylates leading to spirocyclopentane-1,1'-indane systems. This method is quite useful for the construction of an optically active spiro compound and was applied to the synthesis of the optically pure CDEF-ring unit of 1. Cycloaddition of the optically pure CDEF-ring unit to AB-ring units prepared via benzyne afforded two natural and unnatural-type hexacyclic compounds, which were converted to natural and unnatural enantiomers of synthetic 1, and the absolute configuration of natural 1 was determined as S.

Catalytic asymmetric synthesis of 1,1'-spirobi[indan-3,3'-dione] via a double intramolecular C-H insertion process.

A highly efficient one-pot construction of optically active 1,1'-spirobi[indan-3,3'-dione] derivative (up to 80% ee) has been achieved by exploiting the double intramolecular C-H insertion reaction of dimethyl 2,2'-methylenebis(alpha-diazo-beta-oxobenzenepropanoate) under the influence of dirhodium(II) tetrakis[N-phthaloyl-(R or S)-tert-leucinate] as a catalyst.

[Preservation, thawing and infusion of hematopoietic stem cells].

Peripheral blood stem cells can be stored by the following 3 methods: liquid storage, non-rate controlled freezing and rate controlled freezing. Methods of processing of these cells including thawing, ex vivo purging and infusion are described in detail.

Conservative management of post-operative peritoneal cysts associated with endometriosis.

OBJECTIVE: To describe the usefulness of fine-needle aspiration cytology and drainage, followed by long-acting GnRH-agonist therapy in the management of post-operative peritoneal cysts with endometriosis. METHODS: In six women who were diagnosed as having post-operative peritoneal cysts with endometriosis, fine-needle aspiration cytology and drainage was performed. Thereafter, four patients were treated with long-acting GnRH-agonists for 6 months. Two patients refused the treatment. RESULTS: In all patients fine-needle aspiration yielded specimens which consisted of a population of mesothelial cells. The mean follow-up time was 4 years (range 3.5-5). The four patients treated with long-acting GnRH-agonists show no evidence of recurrence. In two patients who had no additional treatment, the recurrence of the cyst was noted 2 months and 5 months after the drainage. CONCLUSION: Combination of fine-needle aspiration cytology and drainage and subsequent long-acting GnRH-agonist therapy can be a useful conservative management of post-operative peritoneal cysts associated with endometriosis.

Body stalk anomaly: prenatal diagnosis.

Body stalk anomaly is a severe body wall defect, with maldevelopment of the hindgut and the presence of a very rudimentary umbilical cord. A case of prenatally-diagnosed body stalk anomaly is presented along with the discussion of the prenatal diagnosis and its management. Autopsy of the fetus showed abnormalities compatible with the maldevelopment of embryonic body folding. Prenatal ultrasonographic diagnosis of body stalk anomaly would permit the early termination of pregnancy or avoidance of surgical intervention.