PubMed Health⌕ Search

Biomedical subjects

S F Yu

Publications and source records attributed to S F Yu.

At least 55 records · Page 3Linked to original sources
PubMed1990

Lung cancer among women in north-east China.

A case-control study of lung cancer involving interviews with 965 female patients and 959 controls in Shenyang and Harbin, two industrial cities which have among the highest rates of lung cancer in China, revealed that cigarette smoking is the main causal factor and accounted for about 35% of the tumours among women. Although the amount smoked was low (the cases averaged eight cigarettes per day), the percentage of smokers among women over age 50 in these cities was nearly double the national average. Air pollution from coal burning stoves was implicated, as risks of lung cancer increased in proportion to years of exposure to 'Kang' and other heating devices indigenous to the region. In addition, the number of meals cooked by deep frying and the frequency of smokiness during cooking were associated with risk of lung cancer. More cases than controls reported workplace exposures to coal dust and to smoke from burning fuel. Elevated risks were observed for smelter workers and decreased risks for textile workers. Prior chronic bronchitis/emphysema, pneumonia, and recent tuberculosis contributed significantly to lung cancer risk, as did a history of tuberculosis and lung cancer in family members. Higher intake of carotene-rich vegetables was not protective against lung cancer in this population. The findings were qualitatively similar across the major cell types of lung cancer, except that the associations with smoking and previous lung diseases were stronger for squamous/oat cell cancers than for adenocarcinoma of the lung.

Adult↗
PubMed1990

Recurrent parotitis in children. A report of 102 cases.

This article presents 102 cases of recurrent parotitis in children with studies of clinical findings, sialographic manifestations, dynamic functions of the parotid gland examined with radionuclide, laboratory findings and follow-up studies of 28 cases with sialography. The following conclusions are reached: 1. Retrograde infection induced by the mumps virus and upper respiratory infection seem to play a major role in the etiology of recurrent parotitis. Familial abnormalities are potential factors. Incomplete immune functions of the children are factors related to the pathogenesis, and following growth and development of the immune system, this disease will undergo remission; 2. Sequential scintigraphy shows normal uptake and retarded excretion function of the parotid; 3. Long-term follow-up studies demonstrate that the patients are free from symptoms for many years, but the punctate dilatation in sialography may diminish, disappear, or be unchanged; and 4. If the disease is not cured in childhood, it may continue into adulthood and healing will take place eventually. Relationship with Sjogren's syndrome has not been revealed.

Adolescent↗
PubMed1989

Role of Na+/H+ exchange by interferon-gamma in enhanced expression of JE and I-A beta genes.

The rapid transductional sequences initiated by interferon-gamma (IFN-gamma) on binding to its receptor regulate functional and genomic responses in many cells but are not well defined. Induction of macrophage activation is an example of such functional and genomic changes in response to IFN-gamma. Addition of IFN-gamma to murine macrophages, at activating concentrations, produced rapid (within 60 seconds) alkalinization of the cytosol and a concomitant, rapid influx of 22Na+. Amiloride inhibited the ion fluxes and the accumulation of specific messenger RNA for two genes induced by IFN-gamma (the early gene JE and the beta chain of the class II major histocompatibility complex gene I-A). The data indicate that IFN-gamma initiates rapid exchange of Na+ and H+ by means of the Na+/H+ antiporter and that these amiloride-sensitive ion fluxes are important to some of the genomic effects of IFN-gamma.

Amiloride↗
PubMed1989

Retroviral vector-mediated high-efficiency expression of adenosine deaminase (ADA) in hematopoietic long-term cultures of ADA-deficient marrow cells.

Two recombinant retroviral vectors encoding the cDNA of the human adenosine deaminase (ADA; EC 3.5.4.4) gene and the bacterial neomycin resistance (Neo) gene have been used to transduce bone marrow cells obtained from four patients affected by the ADA-deficient variant of severe combined immunodeficiency. By utilizing the long-term marrow culture system, freshly isolated bone marrow cells were subjected to multiple infection cycles with cell-free supernatants containing high titers of viral vector and then maintained in long-term marrow culture in the absence of any overt selection pressure. By using this experimental protocol, about 30-40% of the hematopoietic progenitors were productively transduced with the viral vector, as judged by the appearance of G418-resistant colonies derived from granulocyte/macrophage and multipotent hematopoietic progenitor cells. The vector-encoded human ADA gene was expressed efficiently in both the myeloid and lymphoid progeny of the cultured bone marrow cells, reaching levels between 15% and 100% as compared to the levels of ADA in normal bone marrow cells. The efficiency of gene transfer and ADA production was proportional to the number of infection cycles. Furthermore, transduction of the ADA vectors into the bone marrow cells derived from an ADA-deficient patient restored the capacity of the cells to respond to phytohemagglutinin and interleukin 2.

Adenosine Deaminase↗
PubMed1989

[Regulation of osteoclastic bone resorption. 1. Limitation of osteoclast motile activity by fibroblast-like cells].

The cell-to-cell interaction between osteoclasts and fibroblast-like cells, which were mechanically disaggregated from long bones of neonatal rabbits, was investigated to clarify the cellular mechanisms responsible for the regulation of osteoclastic bone resorption by using phase-contrast time lapse recording and fluorescent microscopy for visualization of F-actin cytoskeleton. Osteoclasts showed rapid extension and retraction of pseudopodia with intense ruffling activity and active translocation over a glass surface when there was enough open space around them, while fibroblast-like cells seemed much more stationary. Osteoclasts were not able to cross over cell bodies of fibroblast-like cells which interfered with migration of the osteoclasts. As fibroblast-like cells proliferated, they gradually took over the open glass surface and finally tightly surrounded the osteoclasts. Such osteoclasts usually became contracted and pseudopodial and migratory activities decreased. Fluorescent microscopy of well-spread osteoclaststs stained with rhodamine-labeled phalloidin revealed development of a band-like structure composed of a number of brightly fluorescent F-actin dots at the cell periphery and fine F-actin bundles which run through the cell bodies. On the other hand, contracted osteoclasts tightly surrounded by fibroblast-like cells showed conglomerates composed of accumulated F-actin dots instead of the band-like structure. An F-actin pattern of fibroblast-like cells, which was very different from that of osteoclasts, displayed thick and straight bright bundles with in the cell bodies. The present observation suggests that ongoing osteoclastic bone resorption may be regulated by fibroblast-like cells through limitation of osteoclastic motile activity, and alteration of cytoskeleton and cell-substratum interaction which occurred in osteoclasts may be involved in the mechanism.

Actins↗
PubMed1989

[Direct immunofluorescent technic of analyzing fibrinogen in the differential diagnosis of certain diseases of the oral mucous membrane].

This paper reports the use of direct immunofluorescent technique in diagnoses of 80 cases in which 5 kinds of diseases of the oral mucous membrane are included. The results demonstrate that fibrinogen is deposited in basement membrane zone in 100% of lichen planus cases and 21.4% and 75.0% in chronic lupus erythematosus and benign lymphoid hyperplasia respectively. In leukoplakia and chronic infection it is negative. Therefore, the direct immunofluorescent technique is likely a reliable method for diagnosis of certain kinds of diseases of the oral mucous membrane.

Basement Membrane↗
PubMed1987

Expression of human adenosine deaminase in nonhuman primates after retrovirus-mediated gene transfer.

Primate bone marrow cells were infected with a retroviral vector carrying the genes for human adenosine deaminase (h-ADA) and bacterial neomycin resistance (neor). The infected cells were infused back into the lethally irradiated donor animals. Several monkeys fully reconstituted and were shown to express the h-ADA and neor genes at low levels in their recirculating hematopoietic cells for short periods of time.

Adenosine Deaminase↗
PubMed1987

Effect of internal viral sequences on the utility of retroviral vectors.

Expression of the human ADA cDNA encoded by the Moloney murine leukemia virus spliced RNA form is enhanced by intron-contained sequences. The presence of sequences corresponding to the viral gag gene in a Moloney murine leukemia virus-based vector results in the generation of 10- to 40-fold higher titers of virus.

Adenosine Deaminase↗
PubMed1986

Self-inactivating retroviral vectors designed for transfer of whole genes into mammalian cells.

A retrovirus-derived vector called self-inactivating (SIN) vector was designed for the transduction of whole genes into mammalian cells. SIN vectors contain a deletion of 299 base pairs in the 3' long terminal repeat (LTR), which includes sequences encoding the enhancer and promoter functions. When viruses derived from such vectors were used to infect NIH 3T3 cells, the deletion was transferred to the 5' LTR, resulting in the transcriptional inactivation of the provirus in the infected cell. Introduction of a hybrid gene (human metallothionein-promoted c-fos) into cells via a SIN vector was not associated with rearrangements and led to the formation of an authentic mRNA transcript, which in some cases was induced by cadmium. SIN vectors should be particularly useful in gene transfer experiments designed to study the regulated expression of genes in mammalian cells. Absence of enhancer and promoter sequences in both LTRs of the integrated provirus should also minimize the possibility of activating cellular oncogenes and may provide a safer alternative to be used in human gene therapy.

Chromosome Deletion↗
PubMed1985

Glycolipid receptor for human migration inhibitory factor: fucose and sialic acid are important for the human monocyte response to migration inhibitory factor.

The role of carbohydrate in the interaction of human migration inhibitory factor (MIF) with human peripheral blood monocytes was investigated by studying the effects of different exoglycosidases on the cellular response to MIF. When monocytes were pretreated with neuraminidase, an exoglycosidase specific for sialic acid, they became unresponsive to MIF. Other glycosidases, such as beta-galactosidase and alpha-mannosidase, were inactive in this respect. The effect of neuraminidase was reversible since the response to MIF was restored to normal levels after 24 hr. In parallel studies, a glycolipid-enriched extract from U937 cells, a human macrophage-like cell line, known to enhance the monocyte response to MIF, lost this activity when treated with neuraminidase and alpha-L-fucosidase, but not with beta-galactosidase. This suggests the importance of terminal sialic acid and fucose residues for the interaction between monocyte membrane glycolipids and MIF.

Cell Line↗
PubMed1985

Macrophage glycolipid receptors for human migration inhibitory factor (MIF): differentiated HL-60 cells exhibit MIF responsiveness and express surface glycolipids which both bind MIF and convert nonresponsive cells to responsiveness.

The human promyelocytic leukemia line HL-60 when treated with a phorbol diester (TPA) differentiates into cells (HL60-TPA) that respond to human migration inhibitory factor (MIF). Unresponsive HL-60 cells became responsive to MIF when preincubated with a glycolipid-enriched preparation extracted from HL60-TPA cells, human monocytes, human macrophage-like (U937) cell line, or with the purified glycolipid receptor for MIF from guinea pig peritoneal macrophages. Human blood monocytes exhibited an increased response to MIF when preincubated with glycolipids from HL60-TPA and U937 cells but not from HL-60 cells. Finally, glycolipids from HL60-TPA cells but not from HL-60 cells were able to reversibly bind MIF when covalently coupled to agarose. These studies suggest that TPA induces the differentiation of HL-60 cells into MIF-responsive cells through the expression of a glycolipid receptor for MIF.

Cell Differentiation↗
PubMed1984

Glycolipid-dependent interaction between human migration-inhibitory factor and mononuclear phagocytes.

It has been previously established in the guinea pig that the response of peritoneal macrophages to migration inhibitory factor (MIF) is enhanced by a macrophage glycolipid and that gangliosides reversibly bind MIF. This suggests that glycolipids function as cell surface receptors for MIF. In this report, it is demonstrated that the response of human peripheral blood monocytes to human MIF is augmented by preincubation of these cells with glycolipid-enriched material extracted from the human macrophage-like cell line U937 or human peripheral blood monocytes and with a purified glycolipid from guinea pig peritoneal macrophages. In addition, a mixed ganglioside preparation from bovine brain shows the same effect. In contrast, the pure gangliosides, GM1 and GD1a, and glycolipids from the HL-60 cell line, which is a MIF-unresponsive cell line, were not able to enhance the response to human MIF. The specificity of enhancement by particular glycolipids could not be attributed to an increased uptake of only enhancing glycolipids since there was no significant difference between the association of monocytes with radioactive liposomes containing biologically active or inactive glycolipids. Pronase treatment did not affect the enhancing activity of the U937 glycolipid-enriched material. Incubation of cells with glycolipids results in enhancement only if done at 37 degrees C and not at 4 degrees C. Therefore, the association of lipid with the monocyte surface appears to be dependent on temperature. Further evidence for the receptor nature of these enhancing glycolipids is provided by experiments involving affinity purification experiments. Coupling of bovine brain mixed gangliosides to agarose resulted in a matrix capable of reversibly binding MIF. GD1a-agarose was inactive in this respect.

Animals↗