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Biomedical subjects

L Cao

Publications and source records attributed to L Cao.

At least 199 records · Page 11Linked to original sources
PubMed1995

[Evaluation of acute flaccid paralysis (AFP) surveillance system in 1994].

Increased by 40.2% compared with 1993, 3142 acute flaccidparalysis cases were reported from AFP surveillance system in 1994. A total number of 1297 counties had AFP cases reported, accounting for 45.1% of total amount of counties. Out of 3142 AFP cases, 307 were confirmed, coming from 225 counties. For children under 15 years old, the reported AFP incidence was 1.1/10(5), non-polio AFP rate was 0.83/10(5), much higher than 0.37/10(5), in 1993. 48.5% of the total AFP cases had double stool specimen taken within 0-14 days after paralysis. 79% AFP cases had been investigated within 48 hours after being reported. Some of the major monitoring indicators of AFP surveillance system were close to the WHO criterion, but the percentage of AFP cases reported within 48 hours of careseeking and AFP cases with follow-up visit after 60-70 days of paralysis were very low. Furthermore, 77.9% of the confirmed cases were diagnosea clinically by residual paralysis, so did the 46.4% of discarded cases. It is in urgent need to increase the percentage of cases classified by laboratory test.

Acute Disease↗
PubMed1995

[Epidemiological analysis of poliomyelitis cases in 1994, China].

In 1994, the number of reported polio cases was 307 in China. This number was 53% lower than that in 1993, and was the lowest record ever in China. In 1994, the distribution of polio cases was highly dispersed and the number of outbreak was reduced obviously. Of 225 counties which reported polio cases in 1994, polio outbreak occured in 2 counties. Cases due to polio outbreak accounted for 4.2% of the total cases. The distribution of polio wild virus was narrow but the regional difference still existed. In the southeast, high risk region for polio consisting Guangdong, Hainan, Fujian three provinces, the number of polio cases decreased remarkably in 1994. On the contrary, in the southwest region which, consisting Guangxi, Yunnan, Guizhou, Sichuan four provinces, the number of polio cases increased obviously, accounted for approximately a half of the total number in 1994. During the coming 1 to 2 years, we should emphasis on these regions and provinces where high incidence was noticed in our polio eradication program. Those provinces should include Xinjiang, Fujian. Hubei three provinces that polio wild virus was identified in 1994, and Guangxi, Sichuan, Guizhou, Yunnan in the south west region as well. We should further increase Polio vaccination coverage of children especially floating and unplanned ones through strengthening routine immunization and carring out new national immunization day activity.

Child, Preschool↗
PubMed1995

[Surgical treatment for iatrogenic damage at the confluence of hepatic duct].

Since 1989, 4 patients with iatrogenic bile duct injuries at the level of bifurcation were treated. Among them, the bifurcation together with both right and left hepatic duct had had wrongly been resected in 2 cases. The bifurcation was partially resected in the other 2 cases. The establishment of a permanent hepaticoentertostomy is essential. Abnormal bile flow would impede surgical effect, hence in the author's opinion, peripheral hepaticoenterostomy such as Longmire's procedure is unsuitable for iatrogenic bile duct injuries. The author's special technique for adequate exposure and accurate dissection of intrahepatic bile ducts is described. Four cases have been followed up for 7 months to 5 years with good result.

Adult↗
PubMed1994

Effect of age on cholesterol uptake and utilization by rat adrenals: II. Lipoproteins from young and old rats.

The current study examines whether age-related changes in high density lipoproteins (HDL) influences how these particles are handled by adrenal cells. It appears that HDL from 18- to 20-month-old Sprague-Dawley rats show a seven- to eightfold increase in content of apolipoprotein E compared to HDL from 2- to 5-month-old rats. The 'aged' particles show increased binding to susceptible hepatic membranes, and show a doubling in whole particle endocytosis by cortical cells of the perfused adrenal gland and by isolated adrenal cells from all rats regardless of age. Despite this twofold increase in particle uptake, the increase in total cholesteryl ester uptake by either the perfused adrenal or incubated adrenal cells is minor, amounting to less than 10% of the total cholesteryl ester internalized. This discrepancy occurs since the high apo E content of the 'aged' HDL only affects cholesteryl ester uptake by the 'endocytic' pathway; uptake via the 'selective' pathway (where cholesteryl ester is separated from the rest of the particle at the cell surface and directly internalized) is not altered.

Adrenal Cortex↗
PubMed1994

Macrophages adhere to glucose-modified basement membrane collagen IV via their scavenger receptors.

Scavenger receptors have been reported to mediate macrophage adhesion to serum-coated plastic surfaces. We report here that scavenger receptors promote the divalent cation independent adhesion of human monocytes and macrophages to surfaces coated with non-enzymatically glycated collagen IV but not to surfaces coated with native collagen IV. Ligands for scavenger receptor types I and II blocked adhesion of monocytes and macrophages to non-enzymatically glycated collagen IV but had no effect on adhesion of these cells to albumin-coated surfaces. U937 human promonocyte-like cells transfected with cDNA encoding bovine scavenger receptor I or II adhered to surfaces coated with glycated-collagen IV but not to surfaces coated with native collagen IV. A synthetic peptide homologous to the domain of bovine scavenger receptor that binds modified low density lipoproteins (residues 327-343) inhibited the adhesion of U937 cells transfected with cDNA encoding bovine scavenger receptor II to glycated collagen IV, whereas a control peptide from the alpha helical domain of scavenger receptor II (residues 121-137) had no effect on adhesion of these cells. Macrophages plated on surfaces coated with glycated collagen IV were unable to endocytose acetylated low density lipoproteins from the medium, suggesting that their scavenger receptors were occupied in binding these cells to the substrate. These findings suggest new roles for scavenger receptors in the accelerated development of vascular lesions observed in diabetics.

Amino Acid Sequence↗
PubMed1994

Inverse expression of bcl-2 protein and Fas antigen in lymphoblasts in peripheral lymph nodes and activated peripheral blood T and B lymphocytes.

To examine the regulatory mechanism of apoptosis in lymphoid cells, expression of both bcl-2 protein and Fas antigen was investigated in reactive lymph nodes, in resting lymphocytes from peripheral blood (PBLs), and in PBLs stimulated with pokeweed mitogen, interleukin-4 (IL-4) + anti-IgM antibody, IL-2 + anti-CD3 antibody, phytohemagglutinin + phorbol myristate acetate using immunohistochemistry and flow cytometry. Germinal center cells expressed a large amount of Fas antigen, which is associated with the induction of apoptosis in lymphoid cell lines, in contrast to the lack of bcl-2 protein as an apoptosis inhibitor. On the other hand, mantle zone lymphocytes expressed a high level of bcl-2 protein and less Fas antigen. This inverse expression of bcl-2 protein and Fas antigen was also shown in activated T and B lymphocytes from peripheral blood. These lymphoblasts fell into apoptosis dose-dependently in the presence of anti-Fas monoclonal antibody, but resting lymphocytes that expressed both bcl-2 protein and Fas antigen did not undergo apoptosis. These findings suggest that bcl-2 expression prevents the apoptosis of lymphoid cells induced by the Fas antigen-dependent mechanism and that apoptosis of lymphocytes is exquisitely controlled, at least in part, by regulation of the bcl-2 and Fas genes.

Animals↗
PubMed1994

Human gastric adenocarcinoma cathepsin B: isolation and sequencing of full-length cDNAs and polymorphisms of the gene.

Four full-length cDNA clones coding for preprocathepsin B were isolated from a human gastric adenocarcinoma cDNA library (AGS 1-6-30-1) and analyzed for possible sequence modifications that might be linked to altered intracellular trafficking and secretion of cathepsin B (CTSB) in malignant tumors. Comparison of AGS 1-6-30-1 cDNAs with human kidney/hepatoma cDNAs revealed: (1) three potential N-glycosylation sites instead of two, (2) a nucleotide (nt) substitution in the coding region for the propeptide from GTG to CTG which would result in a Val26-->Leu change, (3) three silent nt replacements in the coding region for the mature protein, (4) five single-nt differences in the 5'- and 3'-UTR (untranslated regions), (5) heterogeneity in the 5'-UTR, and (6) a 10-bp insertion in the 3'-UTR. The 10-bp insertion in the 3'-UTR may alter the stability of CTSB mRNA transcripts and thereby the expression of CTSB. These clones should be useful for expressing human tumor CTSB and analyzing the function of this enzyme in malignant progression. Two restriction-fragment length polymorphisms (RFLPs), EcoRI and TaqI, were detected by Southern blot analysis of genomic DNA from 36 unrelated Caucasians. Inheritance and distribution of the EcoRI alleles (13.0 and 11.0 kb) and the TaqI alleles (5.7 and 4.6 kb) indicated they were independent polymorphisms. In contrast to the EcoRI alleles of 13.0 and 11.0 kb observed in the population survey, genomic DNA from two AGS gastric adenocarcinoma subclones revealed two EcoRI alleles of 13.0 and 7.8 kb.(ABSTRACT TRUNCATED AT 250 WORDS)

Adenocarcinoma↗
PubMed1994

Identification of a control region for expression of the forespore-specific Bacillus subtilis locus spoVA.

The role of a 20 bp conserved region located 45-64 nucleotides 5' of the spoVA transcription start point in Bacillus subtilis and Bacillus licheniformis was investigated by deletion analysis and by mobility shift assay. Deletions 5' of this conserved sequence had little effect on expression of a spoVA-lacZ fusion, whereas deletions extending into the sequence reduced expression of the spoVA-lacZ fusion by 85%. The timing of expression of spoVA was not affected by deletion of the sequence. The region was shown by mobility shift assays to bind specifically to a protein. Binding activity was detected in protein extracts prepared from bacteria 1 h or more after they had started to sporulate, but not in extracts prepared from vegetative bacteria. Mutations in all known spoO loci were screened but none prevented appearance of the binding activity; nor did mutations in any of the stage II and III loci tested. It is concluded that the 20 bp conserved region is the binding site of an activator that is subject to temporal regulation independent of known spo loci.

Bacillus subtilis↗
PubMed1994

Differential regulation of natriuretic peptide receptor activity in vascular cells.

We studied the regulation of the individual natriuretic peptide receptor subtypes by 12-O-tetradecanoylphorbol 13-acetate (TPA) and forskolin in cultured bovine aortic endothelial and smooth muscle cells. In cultured endothelial cells, 10(-8) mol/L TPA caused a reduction in atrial natriuretic peptide (ANP) receptor binding activity that was seen as early as 2 hours after the treatment and reached a maximum (88 +/- 3% of control) after 24 hours, whereas the inhibition of ANP-stimulated cyclic GMP (cGMP) accumulation peaked at 2 hours (62 +/- 13% of control) and returned to control levels after 12 hours. After 24 hours of forskolin (10(-4) mol/L) treatment, ANP binding activity fell to 47 +/- 6%, and cGMP accumulation was 52 +/- 11% of control. Northern blot analysis revealed that 10(-8) mol/L TPA suppressed natriuretic peptide C receptor transcript levels, and forskolin increased levels modestly after 24 hours of treatment. Natriuretic peptide A receptor transcript levels remained unchanged by either treatment. In cultured smooth muscle cells, 10(-8) mol/L TPA suppressed ANP binding activity and ANP-stimulated cGMP formation in a fashion similar to that seen in endothelial cells. TPA treatment also resulted in an inhibition of C-type natriuretic peptide-stimulated cGMP production (59 +/- 7% of control); however, this response persisted for as long as 24 hours after addition of the agonist. Treatment with 10(-4) mol/L forskolin produced a time-dependent inhibition of ANP binding activity and did not inhibit cGMP production stimulated by either ANP or C-type natriuretic peptide. In contrast to the effects seen with endothelial cells, TPA caused a dose-dependent stimulation of natriuretic peptide C receptor mRNA, whereas forskolin was inhibitory in smooth muscle cells. These results indicate that the effects of the kinase activators are a function of the individual receptor subtype as well as the cell in which it is expressed and imply a considerable degree of flexibility in the response to regulatory stimuli.

Animals↗
PubMed1994

[Autopsy practised in modern China].

It's very difficult for autopsy to develop in modern China. Two autopsy rules issued by Ministry of Internal Affairs were of epochal significance. Although Society on Anatomy had been set up by western medical workers, and there were four people willing to offer their own remains after death for autopsy, it was still very difficult to obtain a cadaver for autopsy actually. The main barrier still lay in the feudal morality. Moreover, incomplete law also contributed a factor.

Anatomy↗
PubMed1993

Synthesis, conformational analysis, and the glycosidic coupling reaction of substituted 2,7-dioxabicyclo[4.1.0]heptanes: 1,2-anhydro-3,4-di-O-benzyl-beta-L- and beta-D-rhamnopyranoses.

1,2-Anhydro-3,4-di-O-benzyl-alpha-L-rhamnopyranose was synthesized from L-rhamnose, while the D-enantiomer was synthesized from methyl 6-deoxy-2,3-O-isopropylidene-alpha-D-mannopyranoside. For both of the syntheses, the key intermediates were 2-O-acetyl-3,4-di-O-benzyl-alpha-D- and -alpha-L-rhamnopyranosyl chlorides that were quantitatively prepared from the corresponding diacetates by chlorination. Ring closure of the chlorides was carried out readily with potassium tert-butoxide in oxolane, and crystalline 1,2-anhydro-3,4-di-O-benzyl-beta-D- and beta-L-rhamnopyranose were obtained in high yields. Conformational calculations, which were carried out using vicinal proton-proton coupling constants by the modified Karplus equation, suggested that the conformations of the pyranose rings of the title compounds were basically a half chair (4H5) with some flattening at C-4. Force-field calculations (MMP2) confirmed the experimental conformation with good agreement. The coupling reaction of the 1,2-anhydro-L-rhamnose ether with 1,2;3,4-di-O-isopropylidene-alpha-D-galactopyranose was effected in oxolane by catalysis by a Lewis acid, and only the alpha-linked disaccharide was obtained.

Antigens, Bacterial↗
PubMed1993

Activated platelets form protected zones of adhesion on fibrinogen and fibronectin-coated surfaces.

Leukocytes form zones of close apposition when they adhere to ligand-coated surfaces. Because plasma proteins are excluded from these contact zones, we have termed them protected zones of adhesion. To determine whether platelets form similar protected zones of adhesion, gel-filtered platelets stimulated with thrombin or ADP were allowed to adhere to fibrinogen- or fibronectin-coated surfaces. The protein-coated surfaces with platelets attached were stained with either fluorochrome-conjugated goat anti-human fibrinogen or anti-human fibronectin antibodies, or with rhodamine-conjugated polyethylene glycol polymers. Fluorescence microscopy revealed that F(ab')2 anti-fibrinogen (100 kD) did not penetrate into the contact zones between stimulated platelets and the underlying fibrinogen-coated surface, while Fab antifibrinogen (50 kD) and 10 kD polyethylene glycol readily penetrated and stained the substrate beneath the platelets. Thrombin- or ADP-stimulated platelets also formed protected zones of adhesion on fibronectin-coated surfaces. F(ab')2 anti-fibronectin and 10 kD polyethylene glycol were excluded from these adhesion zones, indicating that they are much less permeable than those formed by platelets on fibrinogen-coated surfaces. The permeability properties of protected zones of adhesion formed by stimulated platelets on surfaces coated with both fibrinogen and fibronectin were similar to the zones of adhesion formed on fibronectin alone. mAb 7E3, directed against the alpha IIb beta 3 integrin blocked the formation of protected adhesion zones between thrombin-stimulated platelets and fibrinogen or fibronectin coated surfaces. mAb C13 is directed against the alpha 5 beta 1 integrin on platelets. Stimulated platelets treated with this mAb formed protected zones of adhesion on surfaces coated with fibronectin. These protected zones were impermeable to F(ab')2 antifibronectin but were permeable to 10 kD polyethylene glycol. These results show that activated platelets form protected zones of adhesion and that the size of molecules excluded from these zones depends upon the composition of the matrix proteins to which the platelets adhere. They also show that formation of protected zones of adhesion by platelets requires alpha IIb beta 3 integrins while the permeability properties of these zones of adhesion are regulated by both alpha IIb beta 3 and alpha 5 beta 1 integrins.

Blood Platelets↗
PubMed1993

Role of facilitative glucose transporters in diffusional water permeability through J774 cells.

We have reported previously that in the presence of an osmotic gradient, facilitative glucose transporters (GLUTs) act as a transmembrane pathway for water flow. Here, we find evidence that they also allow water passage in the absence of an osmotic gradient. We applied the linear diffusion technique to measure the diffusional permeability (Pd) of tritiated water (3H-H2O) through plasma membranes of J774 murine macrophage-like cells. Untreated cells had a Pd of 30.9 +/- 1.8 microns/s; the inhibitors of facilitative glucose transport cytochalasin B (10 microM) and phloretin (20 microM) reduced that value to 15.3 +/- 1.8 (50%) and 11.0 +/- 0.7 (62%) microns/s, respectively. In contrast, no significant effect on Pd was observed in cells treated with dihydrocytochalasin B (Pd = 28.4 +/- 1.5 microns/s). PCMBS (3 mM) inhibited glucose uptake by greater than 95%, and 3H-H2O diffusion by approximately 30% (Pd = 22.9 +/- 1.5 microns/s). The combination of cytochalasin B plus pCMBS reduced Pd by about 87% (Pd = 3.9 +/- 0.3 microns/s). Moreover, 1 mM pCMBS did not affect the osmotic water permeability in Xenopus laevis oocytes expressing the brain/erythroid form of facilitative glucose transporters (GLUT1). These results indicate for the first time that about half of the total Pd of J774 cells may be accounted for by water passage across GLUTs. Hence, they highlight the multifunctional properties of these transporters serving as conduits for both water and glucose. Our results also suggest for the first time that pCMBS blocks glucose transport without affecting water permeation through GLUTs. Lastly, because pCMBS decreases the Pd of J774 cells, this suggests the presence in their plasma membranes of another protein(s) exhibiting water channel properties.

4-Chloromercuribenzenesulfonate↗