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Biomedical subjects

X Fu

Publications and source records attributed to X Fu.

At least 163 records · Page 9Linked to original sources
PubMed1995

Structural requirements of peptide and MHC for DR(alpha, beta 1*0401)-restricted T cell antigen recognition.

We identified functionally important regions of the DR(alpha, beta 1*0401) peptide binding site and present a model of bound peptide. DR(alpha, beta 1*0401)-restricted T cell recognition and peptide binding of Mycobacterium leprae (ML) peptide 38-50 and overlapping peptides from the 18-kDa heat-shock protein were analyzed. ML38-50 is unusual in its restricted binding pattern, binding to only one of five DR4 subtypes and no other DR molecules tested. Amino acid substitutions were introduced into ML38-50 and the DR(alpha, beta 1*0401) peptide binding site at positions likely to influence peptide-MHC or peptide- or MHC-TCR interactions. Peptide binding, T cell proliferation, and computer modeling studies suggest that residues 39F, 42E, and 44D of ML38-50 interact with pockets 1, 4, and 6, respectively, of the peptide binding site. Only DR(alpha, beta 1*0401) substitutions at residues in pockets 4 or 7 prevented binding of ML38-50, while multiple substitutions at other positions negatively affected its T cell recognition. In contrast, T cell recognition of some high affinity ML peptides that overlapped ML38-50, and contained N-terminal extensions, was only abolished with pocket 4 substitutions. An inverse correlation of peptide affinity for DR(alpha, beta 1*0401) with negative effects of MHC substitutions on T cell recognition of the overlapping ML peptides was observed. Thus, some regions, such as pocket 4, dominantly influence T cell recognition of multiple DR(alpha, beta 1*0401)-binding peptides. However, each DR(alpha, beta 1*0401)-binding peptide appears to have unique properties that determine the outcome of its MHC-peptide interactions and the relative importance of other polymorphic pockets.

Amino Acid Sequence↗
PubMed1995

A new cytotoxic dihydroxy sterol from the soft coral Alcyonium patagonicum.

A new sterol, 24-methylenecholest-4-ene-3 beta,6 beta-diol [1] was isolated from the soft coral Alcyonium patagonicum collected from the South China Sea. Its structure was determined by spectral analysis. Compound 1 was cytotoxic against the P-388 cell line with an IC50 value of 1 microgram/ml.

Animals↗
PubMed1995

Enzyme inhibitors: new and known polybrominated phenols and diphenyl ethers from four Indo-Pacific Dysidea sponges.

Extracts and pure compounds isolated from four samples of Dysidea sp. sponges collected from two geographically distinct regions of the Indo-Pacific (Chuuk Atoll and Fiji) were assayed against five different enzyme assays, four of which are relevant to anticancer drug discovery and one of which (15-lipoxygenase) may detect compounds significant in modulating the development of atherosclerotic plaque. The pure compounds that inhibited various enzymes were polybrominated phenols and polybrominated phenoxyphenols. Fourteen of these phenols were isolated, six of which were new compounds. A variety of the phenols inhibited inosine monophosphate dehydrogenase (IMPDH), guanosine monophosphate synthetase, and 15-lipoxygenase. No activity was observed with protein tyrosine kinase pp60v-src or matrix metalloprotease.

Animals↗
PubMed1995

Chemical constituents of halophilic facultatively anaerobic bacteria, 1.

Two new nitrotyramine derivatives, 1 and 2, along with five known aromatic compounds, were isolated from the culture broth of a facultatively anaerobic, halophilic bacterium isolated from a sediment from the Great Salt Plains, Alfalfa County, Oklahoma. The structures of the new compounds were determined from spectral data and were confirmed by synthesis from tyramine hydrochloride. Compound 1 showed cytotoxicity against the murine leukemia P-388 cell line (IC50 3 micrograms/ml).

Animals↗
PubMed1995

A cross-national analysis of family and household structure.

"Profound demographic change has taken place in the past few decades in many countries including decreases in fertility and household size, and increases in divorce and non-traditional living arrangements. This paper analyzes the cross-national variation in these trends by utilizing two data sets. Fertility, marriage/divorce and household structure are modeled as separate domains of family life and tested in a LISREL model. The correlations across these domains are examined along with indicators of socioeconomic development and cultural context. Findings indicate that the level of economic development has direct and negative associations with all three family domains. Culture has an independent effect on family demographics but it does not override the forces of development."

Culture↗
PubMed1995

Acidic fibroblast growth factor reduces rat skeletal muscle damage caused by ischemia and reperfusion.

Acute interruption of arterial blood flow to the extremities is often associated with significant morbidity and mortality. Broad-spectrum mitogenic and non-mitogenic activities of FGFs inspired us to study its protecting effects on tissue injuries in ischemia reperfusion condition. We found that systemic administration of aFGF after reperfusion onset prevented severe skeletal muscle injuries. In rats treated with aFGF, the tissue edema was reduced significantly, the tissue viability was increased, and the muscle fibers contained more succinate dehydrogenase (SDH) and adenosine triphosphatase (ATPase). The pathological results supported the concept of improved prevention with aFGF treatment. The possible tissue protection by aFGF may come from its ability to regulate the concentration of extra- and intracellular calcium ion. Besides, it may moderate other Ca2+ dependent enzyme conversion processes. Also, it may take part in the vascular tone regulation under ischemia and reperfusion conditions. These results suggest further study of tissue ischemia prevention with FGF and its possible mechanisms in the future.

Adenosine Triphosphatases↗
PubMed1995

[Whole organ subserial section examination of occult breast carcinoma].

In mastectomy specimens, the primary foci of occult breast carcinoma were examinated usually by routine histopathological method, but the result was not satisfactory. The detecting rates of primary foci were 50%-56% in China and 45%-75% in some other countries. In this study, whole organ subserial section was performed in 20 cases of occult breast cancer from April, 1988 to February, 1994. Primary foci were found in 16 cases (80%) by microscopic examination. Diameters of 10 foci were less than 1.0cm and the smallest one was 0.3 x 0.1 x 0.1cm. In addition, occult breast cancer with multiple foci was detected in 5 cases (31.25%), which would be very difficult to be found by routine histopathological examination. The possible causes for the failure of detection of the primary foci on whole organ section are discussed.

Adenocarcinoma↗
PubMed1995

[Determination of andrographolide in medicinal preparations by HPLC].

A HPLC procedure has been developed to determine andrographolide in Fencishui. The sample was analyzed on a YWG-C18 column, with methanol-water (38:62) as the mobile phase, and detected at 225nm. The average recovery was 98.42% and RSD 1.69%.

Chromatography, High Pressure Liquid↗
PubMed1995

Ischemia and reperfusion reduce the endogenous basic fibroblast growth factor (bF GF) in rat skeletal muscles.

Polyclonal antibodies directed against human recombinant basic fibroblast growth factor (bFGF) were used in immunohistochemical studies to localize this growth factor in normal and wounded rat skeletal muscles. bFGF immunoreactivity was found mainly in the extracellular matrix, primarily in the endomysium, including the heparin-containing basal lamina and also in the capillary basal membrane of both normal and wounded muscles, however the signal intensity was much stronger in normal muscles. After 4-hour ischemia, about 40% of skeletal muscle fibers lost their bFGF immunoreactivity. Muscles which experienced 4-hour ischemia and 24 reperfusion had only a weaker bFGF immunoreactivity. The pathological results supported the concept of destroyed cell connection and fiber necrosis in ischemia and reperfused muscles. The mechanisms involved in this reduced concentration of bFGF in wounded muscles included oxygen radical activation, inflammatory response and reduced secretion of endogenous bFGF. These results were only partially compatible with the established mitogenic role of this protein and suggested that a reduction of endogenous FGF may partly contribute to a delay in wound healing.

Animals↗
PubMed1995

In vitro effect of Hepes buffer on maintaining the number of gap junction plaques in human myometrium at term.

In human myometrium, at various stages of labour and in correlation with the concentration of progesterone and estradiol in maternal blood the formation of gap junctions has been described previously by electron microscopy and laser confocal microscopy of immunohistochemically stained myometrial sections. The present investigation focused on the effect of continuous exposure of isolated human myometrium at term to Hepes buffer, on the number of gap junction plaques. Biopsies of myometrium were obtained from 5 pregnant women at term: they had an elective caesarean operation in the 37th or 40th week of pregnancy. The biopsies were immersed immediately in Hepes buffer, trimmed under a stereo microscope into small strips and kept in warm (37 degrees C) oxygenated Hepes buffer supplemented with glucose (0.01 mM). Then some strips of myometrium were incubated at 37 degrees C for 10, 20, 40, 55, and 180 min. The number of gap junction plaques were counted: it decreased in strips of myometrium after 10, 20, 40, 55, and 180 min of in vitro experiment (P < 0.01 vs control). In some of our experiments, the decrease in quantity of gap junction plaques was very dramatic and far below 50% of their numbers found in control specimens but never reached the zero value.

Biopsy↗
PubMed1995

[The relationship between serum lipids, apolipoproteins level and bile lipids level, chemical type of stone].

To pick up serum high risk lithogenic factors predisposing one to gallstone formation and protective factors against gallstone formation in gallbladder. We compared serum lipid and apolipoprotein level of patients with gallbladder stone (stone group) with that of patients without gallbladder stone (control group). The correlation between serum lipid, apolipoprotein level and bile lipid level, cholesterol saturated index (CSI), characteristics of lipidemia in different kinds of gallbladder stones were studied. The results showed that the increase of serum Apo A1, C2 and E level in the stone group was more significant than in the control group. But there was no statistical significance in TC, TG, LDL-C, HDL-C, Apo A2, B, C3 level between the stone and control groups. These results suggested that serum apolipoproteins perhaps are more sensitive parameters than serum lipids in distinguishing patients with stones from those without stones. There were different profiles of serum lipid and apolipoproteins in different chemical types of gallbladder stones. Increased level in serum LDL-C, Apo B and ratio of LDL-C/HDL-C were characterized by an index for cholesterol stone, otherwise that in serum TG and Apo C2 an index for pigment stones. There was a positive correlation between serum total cholesterol (TC) or Apo B, C2, C3 and cholesterol amount or CSI in gallbladder bile. Therefore, TC, Apo B, C2, C3 could be considered as high risk lithogenic factors. A positive correlation existed between serum HDL-C and lecithin in gallbladder or common bile duct (CBD) bile as well as between HDL-C and bile acids in CBD bile. Thus, HDL-C might be a protective factor against gallstone formation in gallbladder.

Adult↗