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Biomedical subjects

Y C Liu

Publications and source records attributed to Y C Liu.

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

Septic metastatic lesions of pyogenic liver abscess. Their association with Klebsiella pneumoniae bacteremia in diabetic patients.

Septic metastatic endophthalmitis from Klebsiella pneumoniae liver abscess, first reported in seven cases treated at the Veterans General Hospital, Taipei, Taiwan, between 1981 and 1985, was seen in six similar cases at the same hospital in the subsequent 2 years. We conducted a retrospective search for factors that might be associated with these complications of pyogenic liver abscess. A total of 23 cases with septic metastatic lesions from pyogenic liver abscess were found between 1981 and 1987, and 164 cases of pyogenic liver abscess without septic metastatic lesions were identified as a comparison group. Klebsiella pneumoniae liver abscess, bacteremia, and the underlying diabetes mellitus were significantly more common in the study group than in the comparison group. Of the 23 patients with septic metastatic lesions, there were 14 cases (60.8%) of endophthalmitis or uveitis, 10 cases (43.4%) of pulmonary abscess and/or emboli, six cases (26.0%) of brain abscess and/or purulent meningitis, five cases (21.7%) of bacteriuria and/or prostate abscess, two cases (8.6%) of osteomyelitis and/or pyogenic arthritis, and one case (4.3%) of psoas abscess.

Adult↗
PubMed1991

Studies on bio-antioxidants--prooxidation of vitamin E on the autoxidation of linoleic acid in sodium dodecyl sulfate micelles.

The reaction of vitamin E (alpha-tocopherol) with linoleic acid containing peroxidized linoleic acid has been studied. No significant reaction was found in ethanol solution, whereas in sodium dodecyl sulfate micelles vitamin E reacted rapidly with peroxidized linoleic acid, and thereby induced the peroxidation of linoleic acid, leading to oxygen absorption. The reaction kinetics was studied in detail by u.v. spectroscopy, HPLC and ESR spectroscopy. It was found that the main product was alpha-tocopherone with alpha-tocopheroxy radical as the reaction intermediate. A mechanism involving two consecutive bimolecular reactions between peroxidized linoleic acid and alpha-tocopherol and between peroxidized linoleic acid and alpha-tocopheroxy radical, with rate constant 2.93 and 6.21 mol/L-1s-1 respectively is proposed. The micellar effect on the reaction is discussed.

Antioxidants↗
PubMed1990

Stopped-flow ESR study on the reactivity of vitamin E, vitamin C and its lipophilic derivatives towards Fremy's salt in micellar systems.

The reaction between Fremy's salt and alpha-tocopherol (VE), ascorbic acid (VC) and its lipophilic derivatives ascorbyl-6-caprylate (VC-8), 6-laurate (VC-12) and 6-palmitate (VC-16) were studied by stopped-flow ESR spectroscopy in cetyl trimethylammonium bromide (CTAB) and sodium dodecyl sulfate (SDS) micelles, as a model reaction of these antioxidants with alkyl peroxy radicals in biological systems. The second order rate constants for the reaction of Fremy's salt with VE in CTAB and SDS micelles were found to be 7.9 x 10(3) and 2.2 M-1 s-1, respectively, with as high as a 3600-fold variation. Rate constants for VC, VC-8, VC-12 and VC-16 are 4.3, 35, 53 and 56 x 10(3) M-1 s-1 and 3.3, 2.7, 1.2 and 0.86 x 10(3) M-1 s-1 in CTAB and SDS micelles, respectively. The results demonstrate remarkable effects of the charge type of the micelles and the side-chain of the antioxidants on the antioxidation reactivity in the micelles. It reveals that the inter-micellar diffusion may be the rate-limiting step for antioxidation carried out in micelles.

Antioxidants↗
PubMed1990

Regulation of free calmodulin levels by neuromodulin: neuron growth and regeneration.

Neuromodulin is a neurospecific calmodulin binding protein that is implicated in neurite extension, axonal elongation and long-term potentiation. Yuechueng Liu and Daniel Storm propose that neuromodulin binds and concentrates calmodulin on growth cone membranes and that stimulation of protein kinase C releases high local concentrations of calmodulin in the growth cone. Interactions between released calmodulin and cytoskeleton proteins may affect the polymerization, crosslinking and membrane attachment of cytoskeleton polymers. This local 'softening' of the membrane may be an initial event in filopodia formation and extension.

Amino Acid Sequence↗
PubMed1990

A rapid preparation technique for leucocytes.

A procedure is described for making leucocyte preparations from blood samples fixed ex vivo. Briefly, blood is treated with buffered formaldehyde and the erythrocytes and platelets removed subsequently by lysis and differential centrifugation. The fixed leucocyte preparations can then be processed or fixed further for various types of microscopy as required. In stained preparations examined by light microscopy, the different leucocytes, i.e. lymphocytes, polymorphonuclear leucocytes (PMN) and monocytes, can readily be identified by their characteristic nuclear morphology, and polarized PMN can easily be recognized by their non-spherical shape. Experiments with chemotaxins in vitro indicated that the procedure could be used to determine whether polarized PMN circulate in the blood of normal individuals and patients with inflammatory disease. A study of the blood from eleven normal subjects showed that 84.0 +/- 10.8% (mean +/- 2 SEM) of circulating PMN were spherical, while the majority of the remainder (14.3 +/- 10.5%) were only 'slightly' polarized.

B-Lymphocytes↗
PubMed1990

Pyogenic liver abscess: clinical manifestations and value of percutaneous catheter drainage treatment.

One hundred and sixty-two patients with solitary or multiple pyogenic liver abscesses received surgical or medical treatment in the past 8 years. Fifty-seven patients were treated medically (medical group), 62 patients received medical treatment plus sonogram-guided percutaneous drainage (PCD group), and 43 patients received surgical drainage (surgical group). Aerobic gram-negative rods were the predominant causative microorganisms. Klebsiella pneumoniae was the most common microorganism, occurring in 46.9% (76/162) of the cases. Anaerobes occurred in 16.7% (27/162) of the cases. In the evaluation of treatment, the success rates for these three groups were: medical group, 59.6% (34/57); PCD group, 90.3% (56/62); and surgical group, 83.7% (36/43). This retrospective study confirms evidence from a small series that medical treatment plus percutaneous catheter drainage is efficient and more convenient than conventional surgical drainage for pyogenic liver abscesses. The frequent severe septic emboli to distant organs noted in this series (11.1%; 18/162) are quite unusual and should be anticipated in the future.

Adult↗
PubMed1990

Fungemia: analysis of 43 cases.

This report reviews the cases of 43 patients with 48 episodes of fungemia, and examines the clinical significance of fungemia and the results of treatment. All episodes were nosocomial infections. Candida albicans (60.4%), Candida parapsilosis (16.7%), and Candida tropicals (14.6%) were the most common fungal pathogens isolated from blood cultures. Patients with Candida albicans had a better survival rate than those with other species (p = 0.011). Polymicrobial fungemia was noted in 5 patients (11.6%). Most patients had underlying diseases and predisposing factors. Intravascular catheters (100%), broad-spectrum antibiotics administration (100%), surgical procedures (46.5%) and total parental alimentation (41.9%) were the most common predisposing factors. The clinical manifestations were not characteristic and consisted of nonspecific signs of sepsis. The overall mortality rate was 79%. We did not find any improvement in the mortality rate of our patients treated with amphotericin B. Early recognization, immediate removal of predisposing factors, and correction of underlying conditions is most important for patients with fungemia. We also suggest that fungal infection should be considered early when a febrile patient at high risk dose not improve with broad-spectrum antibacterial therapy.

Adolescent↗
PubMed1990

Inflammatory pseudotumor of the liver with occlusive endophlebitis: report of a case.

Inflammatory pseudotumor (IPT) of the liver is an extremely rare benign tumor. Only 12 cases have so far been reported in the English literature. The etiology and pathogenesis of IPT remain obscure. We herein present an additional case of IPT of the liver with occlusive endophlebitis in a 36-year-old female. Immunohistochemical studies demonstrated the polyclonal nature of the plasma cells in the tumor, including IgA, IgM, IgG, kappa and lambda. The inflammatory pseudotumor should be kept in mind in the differential diagnosis of hepatic space-occupying malignant lesions.

Adult↗
PubMed1990

[Renal involvement in amyloidosis: analysis of 14 cases].

UNLABELLED: 14 cases were investigated between 1963 to 1988. Age ranging from 25-66 (mean 48.2). 9 cases (64%) were over age 50. Diagnosis was established by renal biopsy or autopsy. 11 cases (79%) were primary. 3 cases (21%) were secondary with chronic infection. Besides renal involvement, primary amyloidosis principally affected the heart, gastrointestinal tract and tongue. Hepatosplenomegaly and anemia were found in secondary cases. Proteinuria was found in 14 cases. Nephrotic Syndrome (NS) found in 8 cases, both renal insufficiency and hypertension were 21% respectively. In 3 cases performed renal venography, 2 cases showed renal vein thrombosis. 9 cases (64%) showed kidneys were enlarged. Congo red test showed positive reaction were 100% in secondary and 50% in primary. By light microscopy stained with congo red there was a specific protein deposited in glomeruli and mesangium, by electron microscopy. There was fine amyloid fibrils. These findings are characteristic and to have diagnostic value. CONCLUSION: (1) Renal amyloidosis is not very rare in China. (2) Proteinuria and NS were major clinical manifestations. (3) Renal biopsy and autopsy have diagnostic value, congo red test does not prove the absence of primary amyloidosis.

Adult↗
PubMed1990

[Dose-response relationships of propofol in Chinese].

Propofol is a new intravenous anesthetic which possesses the rapid induction and recovery of anesthesia. It has been approved to be used in clinical anesthesia and critical care medicine since 1989. From the dose-response study of propofol, we can get the ED50 and induction dose of propofol and compare those with other anesthetics. Sixty young patients, ASA I-II, both sexes, were allocated into six groups of ten patients. All of patients did not receive premedicants. Groups I-VI were given intravenously over 25 sec 1.0 mg/kg, 1.2 mg/kg, 1.4 mg/kg, 1.6 mg/kg, 1.8 mg/kg and 2.0 mg/kg, respectively. Blood pressure and heart rate were monitored and recorded before and 1 min, 3 min, 5 min after the injection of propofol. Induction of anesthesia by propofol is considered to be successful as a patient closes his eyes and does not response to simple command. As a patient obeys the order to open his eyes, he is judged to emerge from anesthesia. Induction and recovery times were recorded in each successfully-induced patient. Data were analyzed using Litchfield and Wilcoxon, and Student's t tests. The ED50 of propofol was found to be 1.46 mg/kg (95% confidence interval: 1.35 mg/kg to 1.58 mg/kg). Induction and recovery times at 1.0 mg/kg, 1.2 mg/kg, 1.4 mg/kg, 1.6 mg/kg, 1.8 mg/kg and 2.0 mg/kg were 40 sec and 5.6 min, 38 sec and 6.0 min, 38 sec and 6.2 min, 36.8 sec and 6.7 min, 36.3 sec and 7.2 min, 35.5 sec and 7.2 min, respectively.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1989

Preparation of diazotized polystyrene latex and its use in agglutination assays.

The preparation of this immunological latex consisted of the following steps: the synthesis of polystyrene, polynitrostyrene, polyaminostyrene and polystyrene diazonium salt latex. The quantities of emulsifier and initiator used in the synthesis of the polystyrene latex were much larger than those used in the conventional method. Reduction of the polynitrostyrene latex involved adding latex dropwise to a large excess of 6% sodium hydrosulphite-2 N potassium hydroxide solution with sodium lauryl benzene sulphonate as an emulsifier. When the mixture was heated at 70 degrees C for 4 h, the emulsion of polyaminostyrene was diazotized. The polystyrene diazonium salt latex obtained was capable of combining with 20-40% by weight of antibody protein. The immunopolystyrene diazonium latex reagents showed a positive agglutination reaction of 78-91% when mixed with serum from patients with leptospirosis and two other infectious diseases. The test, which can be completed within 3 min has been used to assay over 1200 patient samples.

Agglutination Tests↗
PubMed1989

Dephosphorylation of neuromodulin by calcineurin.

Neuromodulin (p57, GAP-43, F1, B-50) is a major neural-specific, calmodulin binding protein found in brain, spinal cord, and retina that is associated with membranes. Phosphorylation of neuromodulin by protein kinase C causes a significant reduction in its affinity for calmodulin (Alexander, K. A., Cimler, B. M., Meirer, K. E., and Storm, D. R. (1987) J. Biol. Chem. 262, 6108-6113). It has been proposed that neuromodulin may function to bind and concentrate calmodulin at specific sites within neurons and that activation of protein kinase C causes the release of free calmodulin at high concentrations near its target proteins. It was the goal of this study to determine whether bovine brain contains a phosphoprotein phosphatase that will utilize phosphoneuromodulin as a substrate. Phosphatase activity for phosphoneuromodulin was partially purified from a bovine brain extract using DEAE-Sephacel and Sephacryl S-200 gel filtration chromatography. The neuromodulin phosphatase activity was resolved into two peaks by Affi-Gel Blue chromatography. One of these phosphatases, which represented approximately 60% of the total neuromodulin phosphatase activity, was tentatively identified as calcineurin by its requirement for Ca2+ and calmodulin (CaM) and inhibition of its activity by chlorpromazine. Therefore, bovine brain calcineurin was purified to homogeneity and examined for its phosphatase activity against bovine phosphoneuromodulin. Calcineurin rapidly dephosphorylated phosphoneuromodulin in the presence of micromolar Ca2+ and 3 microM CaM. The apparent Km and Vmax for the dephosphorylation of neuromodulin, measured in the presence of micromolar Ca2+ and 2 microM CaM, were 2.5 microM and 70 nmol Pi/mg/min, respectively, compared to a Km and Vmax of 4 microM and 55 nmol Pi/mg/min, respectively, for myosin light chain under the same conditions. Dephosphorylation of neuromodulin by calcineurin was stimulated 50-fold by calmodulin in the presence of micromolar free Ca2+. Half-maximal stimulation was observed at a calmodulin concentration of 0.5 microM. We propose that phosphoneuromodulin may be a physiologically important substrate for calcineurin and that calcineurin and protein kinase C may regulate the levels of free calmodulin available in neurons.

Animals↗
PubMed1989

Gene expression of PCNA/cyclin in adult tissues and the R3230AC mammary tumor of rat.

We have investigated the gene expression of PCNA (Proliferating Cell Nuclear Antigen)/cyclin in rat tissues and the R3230AC mammary tumor. The steady-state mRNA level of PCNA/cyclin in a tissue is related to the proliferation of the tissue. The observation was confirmed with the results from the studies of the immunoblotting analyses and the DNA polymerase activity measurements. Furthermore, an overexpression of PCNA/cyclin was found in the R3230AC mammary tumor, which is accompanied by an altered PCNA/cyclin gene structure detected with the Southern blot analysis.

Animals↗
PubMed1989

Requirement for proliferating cell nuclear antigen expression during stages of the Chinese hamster ovary cell cycle.

Proliferating cell nuclear antigen (PCNA/cyclin) is a nuclear protein that can stimulate purified DNA polymerase delta in vitro, and its synthesis correlates with the proliferation rate of cells. We have attempted to determine whether synthesis of PCNA/cyclin in Chinese hamster ovary cells is necessary to regulate entry into S phase. We have measured cellular PCNA/cyclin concentration of the mRNA or protein throughout the cell cycle. Cells were separated by centrifugal elutriation into populations enriched for G-1, S, and G-2/M phases. Quantitative Northern hybridization analysis was performed on RNA isolated from each cell population by using a cDNA clone of PCNA/cyclin as a probe. Results demonstrated that although intact PCNA/cyclin mRNA is present during all phases of the cell cycle, an induction of about 3-fold occurs during S phase. Two-parameter staining for PCNA/cyclin and DNA, and analysis by flow cytometry, confirmed that the quantity of PCNA/cyclin protein in the cells increases severalfold in G-1 or early S phase but generally is invariant in S and G-2/M phases. This cell cycle dependence of PCNA/cyclin expression suggests that the observed synthesis is a prerequisite for initiation of DNA replication. Introduction of an antisense oligonucleotide complementary to the PCNA/cyclin mRNA to inhibit PCNA/cyclin synthesis effectively prevented entry of G-1 phase cells into S phase. A complementary sense oligonucleotide used as a control did not have an inhibitory effect. This result suggests that a threshold concentration of PCNA/cyclin is necessary for entry into S phase.

Animals↗
PubMed1989

Localization of fibronectin in the folliculo-stellate cells of the rat anterior pituitary by the double bridge peroxidase-antiperoxidase method.

The localization of fibronectin was demonstrated in the rat anterior pituitary by the highly sensitive double bridge peroxidase-antiperoxidase (PAP) method. The fibronectin immunopositive cells were characterized by stellate-like morphology. The cells immunostained for fibronectin were observed to be identical to those for S-100 protein in adjacent mirror sections, whereas the S-100 protein has been specifically immunodetected in the folliculo-stellate (FS) cells of the anterior pituitary. The present study indicates that the fibronectin is present in the FS cells, suggesting that FS cells might play a role in the regulation of pituitary function through the interaction of fibronectin with hormone secreting cells.

Animals↗
PubMed1989

The effects of the upright position during childbirth.

The purpose of this investigation was to replicate an earlier study to clarify and verify its findings. The 68, term primigravidae married women between the ages of 18 and 25 years were assigned to three groups: (a) one group used a 30 degree upright position with no bearing down instructions during the second stage of labor (n = 24); (b) the second group used a 30 degree upright position with bearing down instructions given during the second stage of labor (n = 22); and (c) a control group used a zero degree recumbent position with bearing down instructions during the second stage of labor (n = 22). The upright position enhanced the descent of the fetal head with a shorter duration of labor in both the first and second stages. When mothers in an upright position were left alone to bear down in response to their own bodies' urges, the second stage of labor was of shorter duration.

Adolescent↗
PubMed1989

Successful treatment of metastatic endophthalmitis. Case reports.

Endophthalmitis is a well-recognized complication of intraocular surgery, penetrating ocular trauma and systemic infection. Metastatic bacterial endophthalmitis is rare. However, once it happens, the visual outcome is very poor. In order to prevent visual damage, early diagnosis and treatment is essential. Due to the blood-ocular barrier, intravitreal drug concentrations are low after systemic administration. Strong antibiotics with good penetration into the vitrous humor are needed to obtain adequate bactericidal concentrations. We report two cases with liver abscess complicated by septic events to the eye. One was uveitis, and the other was endophthalmitis. They were diagnosed early and were successfully treated with parenteral ceftriaxone and good vision was preserved.

Adult↗