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E Fredrickson

Publications and source records attributed to E Fredrickson.

13 recordsLinked to original sources
PubMed2001

Extracts of Flourensia cernua reduce consumption of alfalfa pellets by sheep.

Effects of three extracts (hexanes, ether, and ethanol) from tarbush (Flourensia cernua) on intake of alfalfa pellets by lambs were examined. Forty-five ewe lambs were fed one of five treatments for five days (randomized complete block, three lambs per block on each treatment). Treatments were alfalfa pellets (CON) or alfalfa pellets plus ethanol carrier (CAR), hexanes extract (HEX), ether extract (ETH), or ethanol extract (ETOH). Extracts were applied to alfalfa pellets at the same concentration as in an equivalent amount of tarbush (as fed basis) in experiment 1 and at 10-fold dilutions of that concentration in experiment 2. Treatments were isolated from tarbush leaves by using a sequential extraction with hexanes, diethyl ether, and 100% ethanol. Lambs received 640 g of alfalfa pellets (dry matter basis) each morning and intake was monitored during a 20-min interval. Lambs were maintained and fed alfalfa pellets (4.7% of body weight) as one group except during this interval. In experiment 1, mean intake by lambs during the 20-min interval was 361, 393, 204, 212, and 228 g for CON, CAR, HEX, ETH, and ETOH, respectively (SEM = 28.9). All three extracts decreased intake (P < 0.001) compared to CON or CAR. Intake did not differ among the three extracts (HEX, ETH, and ETOH) or between the two controls (CON and CAR). Mean intake did not differ among treatments in experiment 2 (468, 455, 389, 381, and 431 g for CON, CAR, HEX, ETH, and ETOH, respectively; SEN = 30.5; P = 0. 187). Several compounds are probably responsible for the low palatability and differential use of tarbush typically exhibited by livestock.

Animal Feed↗
PubMed2001

Extracts of Flourensia cernua (L): volatile constituents and antifungal, antialgal, and antitermite bioactivities.

The chemical components of tarbush (Flourensia cernua) leaves were fractionated by extracting successively with hexanes, diethyl ether, and ethanol. Volatile profiles of each fraction were identified by using GC-MS. The hexanes fraction contained mostly monoterpenoids, while the ethanol fraction volatiles were primarily sesquiterpenoids. Crude fractions were tested for activity against fungi, algae, and termites. Application of as little as 1 microg of the essential oil from the hexanes fraction was sufficient to provide visible antifungal activity in bioautography assays. The diethyl ether fraction showed selective activity against the cyanobacterium responsible for the 2-methylisoborneol-induced off-flavor sometimes associated with catfish farming operations. All three fractions exhibited a high degree of antitermite activity.

Animals↗
PubMed1994

Effect of chronic ingestion of tarbush (Flourensia cernua) on ewe lambs.

Efforts to increase livestock utilization of tarbush are being coupled with studies to examine tarbush toxicity. Thirty-eight (19/treatment) ewe lambs were assigned at birth to receive either tarbush or alfalfa (15%, dry matter basis) in a sorghum-based growing ration. Lambs were pen-fed this diet 60 d pre-weaning and 60 d post-weaning. No differences existed between treatments in feed consumption. In the tarbush group, 1 lamb died of unknown causes at 90 d of age, while 3 lambs died between 115 and 120 d of age. There were no deaths in the alfalfa group. Shortly before death, lambs fed tarbush appeared lethargic, disoriented and anorectic. At 122 d of age, 5 lambs were randomly selected from each group. Feces and jugular blood samples were obtained from each lamb before being euthanized and necropsied the following day. All fecal samples were negative for occult blood. Serum gamma glutamyl-transpeptidase (P < 0.001) and aspartate aminotransferase (P < 0.001) activities and platelet counts (P < 0.05) were elevated in lambs fed tarbush, while serum calcium concentrations tended (P < 0.10) to be greater. Histologic examination revealed diffuse liver apoptosis in lambs fed tarbush. These data indicate tarbush leaves cause liver damage when fed for extended periods of time.

Animals↗
PubMed1992

Morphology and laminar distribution of neuropeptide Y immunoreactive neurons in the human striate cortex.

The morphology, laminar distribution, and distribution relative to cytochrome oxidase patches of neuropeptide-Y immunoreactive (NPY-ir) neurons were studied in the human striate cortex. The density of NPY-ir cells was highest in the white matter. NPY-ir neurons were sparsely distributed within the cortical layers. NPY-ir neurons were located in both cytochrome oxidase dense patch and interpatch regions. However, the paucity of NPY-ir neurons in layer III, where cytochrome oxidase patches are most clearly demonstrated, precluded establishing a clear relationship of NPY-ir neurons to cytochrome oxidase patches. NPY-ir neurons exhibited a variety of nonpyramidal morphologies, and many of them had axons with recurrent or looped trajectories. A dense plexus of NPY-ir axons was located just beneath the pia, and these axons were concentrated at the entry points of pial blood vessels. Other NPY-ir neurons had cell bodies or processes in close proximity to cerebral capillaries. These results suggest a role of NPY in cortical metabolism, control of cerebral circulation, or activity-related changes in local blood flow.

Adult↗