(n.) A substance of a resinous nature, obtained from the outer bark of the common European birch (Betula alba), or from the tar prepared therefrom; -- called also birch camphor.
Example Sentences:
(1) Based on spectroscopic data and chemical transformations, the structures of the new constituents were determined as 3-epi-betulinic acid 3-O-beta-D-glucopyranoside 28-O-[alpha-L-rhamnopyranosyl(1----4)-O-beta-D-glucopyranosyl(1----6)]-b eta- D-glucopyranoside and alpha-L-rhamnopyranosyl(1----4)-O-beta-D-glucopyranosyl(1----6)-beta-D- glucopyranose.
(2) The structures of the glycosides have been determined as 28-O-[alpha-L-rhamnopyranosyl(1----4)-O-beta-D-glucopyranosyl(1----6)-be ta-D- glucopyranosides of 3 alpha-hydroxy-lup-20(29)-ene-23,28-dioic acid, 3 alpha,11 alpha- dihydroxy-lup20(29)-ene-23,28-dioic acid and 3-epi-betulinic acid by spectroscopic data and chemical transformations.
(3) In addition to 3-epi-betulinic acid, three triterpene glycosides were isolated from leaves of Schefflera octophylla.
(4) On the basis of spectrometric analysis and physico-chemical constants they were identified as oleanolic acid, betulin and beta-sitosterol-D-glucoside respectively.
(5) A new triterpene saponin was isolated from the roots of Ampelozizyphus amazonicus together with the known 3-O-beta-D-glucopyranosyl-20-O-alpha-L-rhamnopyranosyljujubogenin and the known triterpenes melaleucic acid, 3 beta,27 alpha-dihydroxylup-20(29)-en-28 beta-oic acid, betulinic acid, betulin, lupeol.
(6) The constituents responsible for this activity were identified as uvaol, ursolic acid, and betulinic acid.
(7) From spectroscopic data and chemical transformations the structure of the new constituent was determined as 3-epi-betulinic acid 3-O-sulphate 28-O-[alpha-L-rhamnopyranosyl(1----4)-O-beta-D-glucopyranosyl (1----6)]-beta-D-glucopyranoside.
(8) A phytochemical investigation of Grewia bicolor gave the following results: the petroleum ether extract afforded beta-sitosterol and beta-sitosterol- and triterpene esters, and the triterpenes lupeol and betulin.
(9) megaphyllum gave (E)-betulin-3-p-coumarate [20] and (Z)-betulin-3-p-coumarate [21], both of which appear to be novel.
(10) beta-Sitosterol, betulinic acid, ursolic acid, 2alpha-hydroxyursolic acid, 2alpha,3alpha-dihydroxyurs-12-en-28-oic acid and a new triterpene acid, jacarandic acid, were also isolated.
(11) A new acetylated bidesmosidic triterpenoid saponin has been isolated from the leaves of Schefflera octophylla and structurally elucidated as 3-epi-betulinic acid 3-O-beta-D-6'-acetylglucopyranoside 28-[alpha-L-rhamnopyranosyl(1----4)-O-beta-D-glucopyranosyl(1----6)]-bet a-D-0-glucopyranoside [1].
(12) In addition, 5 mumol betulinic acid markedly inhibited the promoting effect of 2.5 micrograms TPA applied twice weekly on skin tumor formation in mice initiated with 50 micrograms of 7,12-dimethylbenz[a]anthracene, and 5 mumol of sitosterol caused slight suppression.
Birch
Definition:
(n.) A tree of several species, constituting the genus Betula; as, the white or common birch (B. alba) (also called silver birch and lady birch); the dwarf birch (B. glandulosa); the paper or canoe birch (B. papyracea); the yellow birch (B. lutea); the black or cherry birch (B. lenta).
(n.) The wood or timber of the birch.
(n.) A birch twig or birch twigs, used for flogging.
(n.) A birch-bark canoe.
(a.) Of or pertaining to the birch; birchen.
(v. t.) To whip with a birch rod or twig; to flog.
Example Sentences:
(1) Sixty patients with seasonal allergic rhinitis due to birch pollen were enrolled in an open, randomized parallel group study.
(2) If the majority of relevant tree pollens are to be included in a diagnostic or therapeutic programme in Western Sweden it should contain birch, alder, hazel, beech and bog-myrtle allergens.
(3) Bet v I, the major birch pollen allergen, could be extracted easily from pollen, and in low amounts from callus and leaves.
(4) In the case of initially negative tests with positive second and third SPTs the incidence ranged between 3.2% (cat dander) and 4.3% (birch pollen) per year.
(5) The sera that did not detect the 15 kD bands in celery failed to react with both the 15 kD mugwort component and the 14 and 16 kD birch components.
(6) In previous experiments it was found that birch, beech, alder, hazel and oak are pollens with importance in pathogenesis of early pollinosis in our region of Central Europe.
(7) We conclude that in children with birch pollinosis oral immunotherapy with high doses of a biologically potent preparation in enteric-coated capsules is effective, easy to perform, economic and safe.
(8) The patients selected for study were subjects with a combined inhalant allergy to birch pollen and an oral allergy to apple fruit.
(9) In the same area, the birch pollen load was 2.8 times higher, which caused specific IgE in 10.5% as against 3.5% of the other group (P less than 0.01) as well as positive skin prick test in 9.0% as against 3.5% (P less than 0.05).
(10) Moreover, a major pollen allergen in birch (BetvI) has a 44% identity with PvPR1 proteins.
(11) It appears that screening for an IgE-mediated allergy can be performed with a limited number of skin tests (rye grass, timothy, birch, house dust mite and cat).
(12) RAST investigations on the sera of 27 patients suffering from celery allergy showed specific IgE to mugwort and birch in 15 cases; sensitization to mugwort or birch alone only occurred in 5 and 7 cases, respectively.
(13) Nine patients with strictly seasonal allergic rhinitis caused by birch pollen and five healthy nonatopic control subjects participated in the present study, which started 1 wk before the birch pollen season and continued throughout the entire pollen season.
(14) Of all positive RAST reactions observed, 74% were against the following allergens: horse and cat epithelium, birch and timothy pollen, and house dust.
(15) Thus 98% of atopic patients with seasonal allergic rhinitis were detected by an allergen panel consisting of timothy, birch and mugwort.
(16) The sera selected were positive in the RAST for both birch pollen and fruits.
(17) Cross-incubations: birch pollen incubated with antibodies against hazel (Ab-CA), or alder (Ab-AI), showed various intensities of gold labelling for each of the three species.
(18) We have studied the influence of substance P (SP) on the proliferative response of concanavalin A (ConA)-activated peripheral blood lymphocytes from 16 birch pollen-allergic patients, sampled before and during the pollen season, and from 15 normal individuals.
(19) The beavers have felled most of the bankside birch, sycamore and other trees they like to eat and use for their dams.
(20) Nine asthmatic patients with an allergy to birch or timothy underwent bronchial allergen provocations on three different trial days, with intervals of 2 to 5 wk.