Structure and Spectral Properties of β-Carbolines,I: 13C-NMR and Mass Spectra of Decahydro-5H-pyrido[1′,2′;5,1]-imidazo[3,4-a]-β-carbolines

¹³C-NMR and the electron impact mass spectra of the β-carboline derivatives 1 – 18 were examined. The structure of the possible diastereomers is discussed. A quantitative relationship between the relative intensity of ions a in the mass spectra of 1 – 18 and the structure of substituents R was found.     

Tongue oximetry in children with extensive thermal injury: comparison with peripheral oximetry

We undertook a prospective study of standard peripheral pulse oximetry versus a modified pulse oximeter probe applied to the tongue in order to determine the efficacy of this alternative monitoring site in children with thermal injuries. Ten patients with a mean age (± SD) of 7.5 ± 4.5 yr were studied on 15 occasions. The mean weight +- SD) was 31.4+- 13.7 kg and percent surface area burn (± SD) was 56+- 21%. A total of 1,992 min of anaesthesia time was monitored. Both sites functioned simultaneously 47% of the time; the lingual but not the peripheral site functioned 28% of the time and only the peripheral site and not the lingual functioned 22% of the time. Neither site functioned 3% of the time. The tongue oximeter provided 563 min more monitoring time than the peripheral sites. The tongue oximeter also functioned in children with peripheral vasoconstriction when the peripheral sensor failed and was less susceptible to electrocautery interference. The tongue oximeter is a reasonable adjunct but not a substitute for peripheral oximetry since its application is limited to paralyzed, intubated patients.     

Role of apoptosis in basal cell and squamous cell carcinoma formation

Long-term ultraviolet-light (UV) exposure of human skin epidermis is associated with an increased risk for the development of skin cancers, such as melanoma, basal cell carcinoma (BCC) and squamous cell carcinoma (SCC). UV radiation not only induces DNA damage in epidermal cells, it also interferes with skin homeostasis, which is maintained by a unique distribution pattern of apoptosis-inducing and -preventing molecules. If the DNA damage is not repaired or the damaged cells are not eliminated by apoptosis, the consequence can be cell transformation, uncontrolled proliferation and eventually skin tumor formation. An important "repair" gene is the p53 suppressor gene. Excessive UV exposure can mutate the p53 gene leading to the loss of its repair function and thus apoptosis resistance of the DNA-damaged cell. For BCC formation an additional pathway has been identified. Mutation of genes of the Hedgehog signaling pathway evokes the downregulation of apoptotic genes and upregulation of anti-apoptotic genes preventing the elimination of damaged cells. In addition, BCC and SCC strongly express the apoptosis-inducing Fas-ligand (FasL) which may help the tumor to escape the attack of immune effector cells. Silencing the genes involved in tumor formation by RNA interference might become a promising new approach to treat skin tumors.     

Telechelic poly(ε-caprolactone) terminated at both ends with OH groups and its derivatization

The synthesis of highly uniform (1,08 ≤ M _w/M _n ≤ 1,13) telechelic poly(ε-caprolactone) terminated at both ends with OH groups and its derivatization leading to poly(ε-caprolactone) with pyrene end-groups are described. The synthesis, carried out in THF at room temperature, involves initiation with (CH₃CH₂)₂AlO(CH₂CH₂O)₃Al(CH₂CH₃)₂, leading to poly(ε-caprolactone) macromolecules growing at both ends. The active centers were deactivated with acetic acid, giving macromolecules with OH end-groups. Reaction of α,ω-dihydroxypoly(ε-caprolactone), HO-poly(εCL)-OH, with 4-(1-pyrenyl)butyryl chloride yields α,ω-di-1-pyrenylpoly(ε-caprolactone), Py-poly(εCL)-Py. Polymers are characterized by GPC, ¹H NMR, and UV spectroscopies. The UV spectra of polymers with pyrene end-groups are compared with the UV spectra of the model compound.     

Chain transfer to ethers in the 3,3-bis(chloromethyl)oxetane polymerization catalyzed by Al(iso-C4H9)3

In the polymerization of 3,3-bis(chloromethyl)oxetane catalyzed by Aliso-C₄H₉/water catalyst, according to the previously reported data (FURUKAWA, SAEGUSA et al.) insoluble polymers are formed. Although neither the exact mechanism of oxetanes polymerization in the presence of AIR₃/H₂O catalysts nor the nature of the insoluble polymers are known it is possible to use chain transfer agents to obtain perfectly soluble polymers. The addition of low molecular weight ethers (C₂H₅)₂O, (n-C₄H₉)₂O, (Allyl)₂O, 1,4-dioxane, (β-ClC₂H₄)₂O, CH₃OPh, and (C₆H₅)₂O in low concentrations leads to the formation of soluble polymers with a very large range of mol. wts. (up to 10⁶). The chain transferabilities of ethers increase with their proton-attracting powers (basicity). In the presence of a chain transfer agent the kinetics of polymerization virtually changes. On the basis of the discussion of the general kinetic behaviors of the system and the dependence of D?P? on conversion it was deduced that in this type of polymerization long living species are formed.     

Acceleration of the Menstrual Cycle by Intercourse

Hazard statistics were applied to an extensive set of prospective data to test for an acceleration of the menstrual cycle by intercourse. Intercourse appeared to accelerate both the basal body temperature (BBT) shift and the onset of menses. Menses was accelerated more by a combination of follicular and luteal intercourse than by luteal intercourse alone (using the BBT shift as an ovulation indicator). The accelerator effects of intercourse therefore appear to cumulate across the menstrual cycle.