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Biomedical subjects

C Liu

Publications and source records attributed to C Liu.

At least 847 records · Page 47Linked to original sources
PubMed1989

Intra-articular amphotericin B treatment of Sporothrix schenckii arthritis.

Arthritis caused by Sporothrix schenckii may not respond satisfactorily to a full course of intravenous amphotericin B therapy. Left untreated, the fungus continues to be recovered from cultures of joint fluid, and the patient typically has serious joint disability. We have shown in one patient with sporotrichosis of the knee that direct low-dose injections of amphotericin B can be performed safely, resulting in eradication of the fungus. The patient has had continued useful range of motion and weight bearing on the involved knee.

Amphotericin B↗
PubMed1988

Transforming growth factors produced by normal and neoplastically transformed rat liver epithelial cells in culture.

The secretion of transforming growth factors (TGFs) alpha and beta by normal, chemically transformed, and malignant rat liver epithelial cell lines was investigated. The WB-F344 normal cultured rat liver epithelial cell line does not secrete an epidermal growth factor-like (putatively TGF-alpha) activity, but several clonal cell strains derived from WB-F344 cells which had been treated with N-methyl-N'-nitro-N-nitrosoguanidine, especially those that expressed high levels of gamma-glutamyl transpeptidase, secreted TGF-alpha-like activity into their conditioned media. Cell lines obtained from tumors which were produced by these cell strains varied in their abilities to secrete TGF-alpha, even though they all expressed high levels of gamma-glutamyl transpeptidase activity. When two of the non-TGF-alpha-secreting tumor cell lines were transplanted into isogeneic rats, the tumors that formed contained high levels of TGF-alpha-like activity. Although epidermal growth-factor (hence, TGF-alpha also) inhibited the proliferation of several of these tumor cell lines in monolayer cultures, this growth factor often paradoxically stimulated the anchorage-independent growth of the same cell lines. In contrast to TGF-alpha-like activity, all cell lines/strains released TGF-beta activity into their conditioned media. However, while both normal or chemically transformed cell strains typically produced the inactive form of TGF-beta, the tumor cell lines tended to produce activated TGF-beta de novo. Anchorage-independent growth of cell lines that produced active TGF-beta was either stimulated, inhibited, or unaffected by TGF-beta. Cell lines that were inhibited by TGF-beta concurrently produced TGF-alpha which was usually able to overcome the negative "autocrine" effect of TGF-beta. We conclude that both TGF-alpha and TGF-beta, singly or in combination, are variously involved in the growth of transformed rat liver epithelial cells. TGF-alpha has a predominantly positive autocrine action on the growth of rat liver epithelial tumor cell lines. The "paracrine" effect of TGF-beta may be at least as important as its autocrine effect in the growth of these transformed epithelial cell lines.

Animals↗
PubMed1988

Cure of brain abscess caused by Nocardia asteroides resistant to multiple antibiotics.

A 29-year-old man with pulmonary infiltrates due to pulmonary alveolar proteinosis had Nocardia asteroides pneumonia and brain abscess. The nocardial infections persisted after therapy with sulfonamides, minocycline, and cefotaxime. Based on the susceptibility studies and serum antibiotic concentrations, he was treated with minocycline, 400 to 600 mg daily, cefotaxime, 12 to 30 gm daily, and probenecid for 15 months. Proteinuria observed near the completion of therapy was transient. Three years after therapy, the infections appear to have been cured.

Adult↗
PubMed1988

Embolization: an adjunctive measure for removal of carotid body tumors.

Small carotid body tumors that do not encircle the internal carotid artery are excised with relative ease and minimal risk by the conventional subadventicial approach. Large carotid body tumors frequently encircle the internal and external carotid arteries, and extensive bleeding often complicates the resection, increasing the risk of carotid artery rupture and damage to major cranial nerves. Recent improvements in surgical techniques and selective embolization have lessened the risks of surgical excision, decreased the blood loss, and diminished the time required for resection. Experiences in the resection of carotid tumors with and without embolization are compared. Early resection of carotid body tumors, before involvement of the internal carotid artery and carotid bulb, is advocated.

Adult↗
PubMed1988

Inhibition of growth of early passage normal rat liver epithelial cell lines by epidermal growth factor.

The proliferation of newly derived or early passage nonparenchymal rat liver epithelial cell lines in serum-containing medium was inhibited consistently by epidermal growth factor (EGF). Inhibition of proliferation by EGF was a dominant effect which could not be overcome by insulin, phorbol ester or substances which raised the intracytoplasmic concentration of cyclic-AMP (cholera toxin and dibutyryl cyclic-AMP). EGF has a heterogeneous effect on colony formation by individual cells of early passage cell lines. Whereas the colony-forming ability of a majority of these cells was inhibited by EGF, a small fraction of the cells resisted this effect and formed colonies in the presence of EGF. Clonal strains of EGF-inhibited and EGF-stimulated cells were isolated. Measurement of 125I-EGF binding capacity of these cell strains revealed no significant differences between the EGF-inhibited and EGF-stimulated cells. In general, EGF-stimulated cell strains demonstrated faster growth rates and higher colony-forming efficiencies than EGF-inhibited strains. EGF-induced growth inhibition however, was an unstable phenotype that might be diminished or lost after multiple passages, especially when cells were allowed to remain confluent for many days between passages. These observations may explain the consistent findings that in late passage, rat liver epithelial cell lines in which the conditions for culture and times of subcultures have not been controlled rigorously, the inhibitory effect of EGF usually is not observed.

Animals↗
PubMed1987

Inhibition of proliferation of cultured rat liver epithelial cells at specific cell cycle stages by transforming growth factor-beta.

Proliferation of early-passage propagable cultured rat liver epithelial cells derived from normal adult rats is markedly inhibited by transforming growth factor-beta (TGF-beta). Inhibition, which is completely reversible, is effected at two distinct points of the cell cycle, the G1/S border and the G0 or early G1 phase. With increasing passages in culture, hepatic epithelial cells progressively become less sensitive to the inhibitory effect of TGF-beta.

Animals↗
PubMed1987

Simultaneous demonstration of bone alkaline and acid phosphatase activities in plastic-embedded sections and differential inhibition of the activities.

Bone alkaline (AlP) and acid phosphatase (AcP) activities were simultaneously demonstrated in tissue sections obtained from mice, rats, and humans. The method involved tissue fixation in ethanol, embedding in glycol methacrylate (GMA), and demonstration of AlP and AcP activities employing a simultaneous coupling azo dye technique using substituted naphthol phosphate as a substrate. AlP activity was demonstrated first followed by AcP activity. Both enzyme activities were demonstrated in tissue sections from bones fixed and/or stored in acetone or 70% ethanol for up to 14 days or stored in GMA for 2 months. AlP activity in tissue sections from bones fixed in 10% formalin, 2% glutaraldehyde, or formal-calcium, however, was markedly inhibited after 3-7 days and was no longer detectable after 14 days of fixation. Moreover, AlP activity was diminished in tissue sections from bones fixed in 70% ethanol or 10% formalin and subsequently demineralized in 10% EDTA (pH 7) for 2 days, and the activity was completely abolished in tissue sections from bones subsequently demineralized in 5% formic acid: 20% sodium citrate (1:1, pH 4.2) for 2 days. Methyl methacrylate (MMA) embedding at concentrations above 66% completely inhibited AlP activity. AcP activity, however, was only partially inhibited by formalin, glutaraldehyde, or formal-calcium after 7 or 14 days of fixation or by MMA embedding and was unaffected by the demineralizing agent formic acid-citrate for 2 days. While AcP activity was preserved in bones fixed in formalin and subsequently demineralized in EDTA, the activity was completely abolished when EDTA demineralization was carried out on bones previously fixed in 70% ethanol.(ABSTRACT TRUNCATED AT 250 WORDS)

Acid Phosphatase↗
PubMed1987

Changes of SCE frequency and chromatin molecular composition in rat progeny whose mothers were treated with oral contraceptives in early pregnancy.

Wistar female rats were fed with oral contraceptives (OC, containing ethinylestradiolum and methylnorethrindronum) in early pregnancy. The dosage used for rats was 6.6 times more than the clinical dosage for humans in weight per kilogram. The SCE frequencies of liver and ovary cells and the changes of chromatin molecular composition in progeny of the rats fed with OC were observed. The results showed that the liver and ovary cells of newborns 12 h after birth exhibited increased SCEs value (liver: p less than 0.03; ovary: p less than 0.0004). These elevated SCE frequencies declined to the normal level about the 15th day after birth. The results for the quantity of nonhistone (NHP) and chromatin RNA in mother rats and their progenies also exhibited a significant increase, and declined to the normal level at the same period mentioned above. The results suggested that the high level of NHP and chromatin RNA may be induced by OC fed in early pregnancy and be maintained for some time after withdrawal of the OC pills. The changes of the chromatin molecular composition are perhaps somehow related to the increased SCE frequencies in the rat-liver cells. We suggest that the external steroids and their metabolites may activate more genes which were originally inactive and result in increased junctions between euchromatin and heterochromatin, resulting in more SCEs in quickly dividing embryo cells. The report here suggests that during early pregnancy the pills taken by women following OC failures may have a potential mutagenic effect on their progeny for some time after the pills have been stopped.

Animals↗
PubMed1987

Bactericidal activity of deptomycin (LY146032) compared with those of ciprofloxacin, vancomycin, and ampicillin against enterococci as determined by kill-kinetic studies.

This study used kill-kinetic methods to provide data on the bactericidal activity of subinhibitory (1/2 X MIC), inhibitory (1 x MIC), and suprainhibitory (4X, 6X, and 8X MIC) concentrations of deptomycin (LY146032) against strains of enterococci compared with those of ciprofloxacin, vancomycin, and ampicillin. Deptomycin was the most active agent tested, as determined by broth microdilution methods, with all strains being inhibited at concentrations less than or equal to 2 micrograms/ml. The kill-kinetic demonstrated that deptomycin had greater activity at all concentrations tested than the other cell wall-active agents; regrowth was seen, however, at lower concentrations. At higher concentrations (6X and 8X MIC), all agents tested demonstrated the same or less bactericidal activity than at 4X MIC, presumably due to the Eagle effect. Nevertheless, these results suggest that further evaluation of deptomycin as a therapeutic agent for serious enterococcal infections is warranted.

Ampicillin↗
PubMed1987

Activity of LY146032 compared with that of methicillin, cefazolin, cefamandole, cefuroxime, ciprofloxacin, and vancomycin against staphylococci as determined by kill-kinetic studies.

Kill-kinetic methods were used to provide data on the bactericidal activity of subinhibitory (0.5x MIC), inhibitory (1x MIC), and suprainhibitory (4x MIC) concentrations of LY146032 against methicillin-susceptible and -resistant Staphylococcus aureus and Staphylococcus epidermidis. These bactericidal activities were compared with those of methicillin, cefazolin, cefamandole, cefuroxime, ciprofloxacin, and vancomycin. LY146032 was among the most active of the antistaphylococcal agents tested, as determined by broth microdilution methods, with all strains being inhibited at concentrations of less than or equal to 1 microgram/ml. Time kill-kinetic studies demonstrated that at 4x MIC, LY146032 was rapidly bactericidal against all strains of staphylococci. Our data show that LY146032 has significant bactericidal activity against staphylococci in comparison with other antistaphylococcal agents. Further evaluation of LY146032 against serious staphylococcal infections is warranted.

Anti-Bacterial Agents↗