Search PubMed⌕ Search

Biomedical subjects

F Gao

Publications and source records attributed to F Gao.

At least 253 records · Page 14Linked to original sources
PubMed1991

Structure of the flavone hymenoxin.

2-(3,4-Dimethoxyphenyl)-5,7-dihydroxy-6,8-dimethoxy-4H-chromen-4-o ne, C19H18O8, Mr = 374.38, monoclinic, P2(1)/n, a = 9.026(4), b = 15.054(6), c = 12.829(6) A, beta = 100.98(4) degrees, V = 1711(1) A3, Z = 4, Dx = 1.450 g cm-3, lambda (Mo K alpha) = 0.71073 A, mu = 1.07 cm-1, F(000) = 784, T = 295 K, R = 0.0778 for 2280 independent reflections. The nearly planar AB ring system (0.04 A r.m.s.d.), O(1) to C(10), and the planar C ring (0.001 A r.m.s.d.) are almost coplanar with an interplanar angle of only 4.4(4) degrees. The methyl groups at C(6) and C(8) are rotated out of the molecular plane on opposite sides with torsion angles C(5)C(6)O(6)C(11) = -94.5(4) and C(7)C(8)O(8)C(12) = 109.0(4) degrees. The methyl groups of ring C are coplanar with the ring, C(3')C(4')O(4')"(13) = 0.2(5) and C(6')C(5')O(5')C(14) = 1.3(5) degrees. The carbonyl group forms an intramolecular hydrogen bond with O(5), O(5)...O(4) = 2.612(5), H(5O)...O(4) = 1.85(4) A, O(5)-H(5O)...O(4) = 151.9(8) degrees, and an intermolecular hydrogen bond with O(7) of an adjacent molecule, O(7)...O(4) (-0.5 + x, -0.5 - y, 0.5 + z) = 2.689(5), H(7O)...O(4) = 1.92(4) A, and O(7)-H(7O)...O(4) = 163.2(8) degrees.

Flavonoids↗
PubMed1991

Effect of low concentrations of nitrous oxide and isoflurane on peak velocity of saccadic eye movements.

Peak velocity of saccadic eye movements was studied in six healthy volunteers who were each given, on separate days, 5% and 10% MAC of nitrous oxide (5% and 10% end-tidal) or of isoflurane (0.06% and 0.12% end-tidal) or air, each gas for 25 min. Subjective assessment following each treatment was also undertaken. No significant difference was found between air and either 5% or 10% nitrous oxide. However, significant differences occurred at 15 and 25 min after 0.06% isoflurane compared with air (P less than 0.05) and highly significant differences were present 5, 15 and 25 min after 0.12% isoflurane when compared with air and nitrous oxide (P less than 0.01). In contrast, there was little difference between the three gases by subjective assessment.

Adult↗
PubMed1991

Effect of sub-anaesthetic infusions of propofol on peak velocity of saccadic eye movements.

Peak velocity of saccadic eye movements was studied in six healthy volunteers who received either 0.9% sodium chloride (as a control) or a stepwise rising propofol infusion regime of 0.24, 0.6 and 1.5 mg kg-1 h-1, which produced arterialized venous concentrations equivalent to 1%, 6% and 13% of the estimated EC50 for propofol. The infusion lasted for 75 min (25 min at each infusion rate) and was followed by a 2-h post-infusion recovery period. Peak saccadic velocity was highly significantly depressed during the 15-25-min period after the start of the second and third propofol infusions compared with saline. The relationship between arterialized venous blood concentration and peak saccadic velocity was similar during recovery when concentrations were falling to that during increasing blood propofol concentrations. Peak saccadic velocity decreased linearly with increasing log10 propofol concentration in the range of 25-800 ng ml-1 (14% of control per decade). Measured arterialized venous-blood propofol concentrations were variable, and systematically greater than computer predictions at the two higher infusion rates. In only half the subjects were the subjective assessments significantly correlated with log10 propofol concentrations or with percentage reduction in peak saccadic velocity.

Adult↗
PubMed1990

[Clinical classification of altitude sickness: analysis of 13,403 cases].

The clinical classification and characteristics of various types of plateau sickness were reported after analysing 13,403 such cases in Tibet region. The conception of plateau sickness and the opinion of its classification in China and abroad were discussed and the names suggested for various types of the disease were also given. However, the rationality of different classifications of the sickness was questioned according to the present understanding of its pathology and clinical manifestations. It is the opinion of the authors to divide this sickness, first of all, into two categories of acute and chronic and then to subdivide each of them into several types according to clinical symptoms and the pathological changes of principally encroached organs. The acute category was subdivided into 4 types as follows: 1. high altitude acute response (HAAR); 2. high altitude pulmonary edema (HAPE); 3. high altitude cerebral edema (HACE); 4. high altitude children cardiopathy (HACC). The chronic category was subdivided into 5 types as follows: 1. high altitude chronic response (HACR); 2. high altitude erythoblastosis (HAEb); 3. high altitude adult cardiopathy (HAAC); 4. high altitude hypertension (HAHyper); 5. high altitude hypotension (HAHypo). This classification is useful in clinical practice and research.

Adolescent↗
PubMed1989

A LINE 1 sequence interrupts the rat alpha 2u globulin gene.

The rat alpha 2u globulin gene family is composed of about 25 members with closely related structure. Several of these genes are transcriptionally active in the liver of adult males. We isolated about 50 independent genomic clones from the library and determined complete nucleotide sequences of two. Although they were alike and revealed structural features prerequisite for active genes, one cloned gene was interrupted in the 6th intron with about 900 bp 5' truncated and 3'-terminal triplicated form of LINE 1 sequence flanked by 16 bp complete direct repeat originating from the 6th intron. Within the inserted LINE 1 an excellent splicing acceptor homologue with a precedent lariat junction motif and multiple polyadenylation signals was identified. Thus, the possible production of a chimeric RNA, the last exon of which would be replaced by a part of LINE 1, has to be considered.

Alpha-Globulins↗
PubMed1989

Length heterogeneity in rat salivary gland alpha 2 mu globulin mRNAs: multiple splice-acceptors and polyadenylation sites.

Rat alpha 2 mu globulins are coded for by a family of about 25 structurally related genes, some of which are expressed in the male adult liver while the other subset seems to be active in several excretory organs, including salivary and lacrymal glands. To estimate the number and specificity of genes expressed in the salivary glands, we determined nucleotide sequences of 30 cDNA clones. At least two alpha 2 mu globulin genes are active and two thirds of mRNAs were shown to code for the peptide two amino acids shorter than the others. Unexpected observation was the intense length polymorphism in the 3' non-coding 6th intron-7th exon regions presumably caused by alternative splice-acceptor selection. At least six acceptor sites were utilized and the longest type retained the entire 6th intronic sequence resulting in a formation of unusually longer product. A stable mRNA molecule of this type was demonstrated in salivary glands by Northern blotting probed with the 6th intron-specific fragment. Together with three independent polyadenylation sites, the rat salivary glands generate a diverse set of alpha 2 mu globulin mRNAs.

Alpha-Globulins↗
PubMed1988

[Multifactorial analysis of survival in breast cancer].

Eleven clinical and pathological factors were eligible for study in relation to the survival of 617 female patients with breast cancer treated by radical mastectomy. All the patients have been followed for more than five years. The data were analyzed by the Cox's proportional hazards regression model. A final set of five independent significant prognostic factors was obtained. In order of importance, they were clinical stage, age at diagnosis, axillary lymph node status, histologic type and size of the primary. To test the time-dependency of these factors using Cox's model, all except age reduced their prognostic impact significantly after five years, however, age was a powerful prognostic factor for long-term survival. A prognostic index based on the regression coefficients was constructed. This index can give a better prediction for our patients' survival and be taken as reference when formulating treatment protocols for breast cancer.

Adult↗
PubMedDate not supplied

Modulation of horizontal cell function by GABA(A) and GABA(C) receptors in dark- and light-adapted tiger salamander retina.

The physiological function of GABA transporters and GABA receptors in retinal horizontal cells (HCs) under dark-and light-adapted conditions were studied by whole-cell voltage clamp and intracellular recording techniques in retinal slices and whole-mounted isolated retinas of the larval tiger salamander. Puff application of GABA in picrotoxin elicited a NO-711 (a potent GABA transporter blocker)-sensitive inward current that did not exhibit a reversal potential in the physiological range, consistent with the idea that these HCs contain electrogenic GABA transporters. Application of GABA in NO-711 elicited a chloride current in HCs; about half of the current was suppressed by bicuculline or I4AA (a GABA(C) receptor antagonist), and the remaining half was suppressed by bicuculline + I4AA or picrotoxin. In whole-mount retinas, NO-711, bicuculline, I4AA, or picrotoxin hyperpolarized the HCs and enhanced the light responses under dark-adapted conditions, and blocked the time-dependent recovery of HC membrane potential and light responses during background illumination. Based on the parallel conductance model, GABA released in darkness mediates a chloride conductance about three times greater than the leak conductance or the glutamate-gated cation conductance. About half of this chloride conductance is mediated by GABA(A) receptors, and the other half is mediated by GABA(C) receptors. These results suggest that GABA released from HCs through the NO-711-sensitive GABA transporters activates GABA(A) and GABA(C) receptors, resulting in chloride conductance increase which leads to a HC depolarization and reduction of the light response. Additionally, GABA transporters also mediate GABA release in background light that is responsible for the recovery of HC membrane potential and light responses.

Adaptation, Ocular↗