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Biomedical subjects

K Liu

Publications and source records attributed to K Liu.

At least 289 records · Page 16Linked to original sources
PubMed1997

Study on small hepatocellular carcinoma and its extension.

This paper summarizes the "study on small hepatocellular carcinoma and its extension" in Liver Cancer Institute, Zhongshan Hospital of Shanghai Medical University during the past 25 years. The results indicated that it was an important approach to obtain long-term HCC survivors, of the 239 patients with 5-year survival, small HCC resection accounted for 51.4%. It was an effective approach to improve the prognosis of HCC in the entire series, the 5-year survival of inpatients treated in authors' institution was 4.8% in 1958-1970, 12.2% in 1971-1983, and 46.7% in 1984-1995; which were correlated to the increase proportion of small HCC resection in the series; it was more effective as compared to large HCC resection, the 5 year survival was 61.3% (n = 645) versus 33.6% (n = 950). Extensions of small HCC study included early detection and treatment of small recurrent HCC, of the 147 patients with re-resection, the 5-year survival was 48.9% calculated from the time of first resection. Another extension was conversion of large HCC into small HCC, using multimodality combination treatment, 72 out of the 663 patients with surgically verified unresectable HCCs have been converted to resectable, 5-year survival being 62.1%, which was comparable to that of small HCC resection. Studies on related basic aspect of small HCC such as cell origin of recurrence, and molecular aspect of small HCC, indicated that biological characteristics, particularly the tumor invasiveness, remained the key link for further prolong survival after small HCC resection. Recently, a "patient-like" human HCC metastatic model in nude mice has been established. Experimental interventions have also been tried. Clinical trials for prevention of recurrence after small HCC resection have shown preliminary encouraging results. However, the "cost-effectiveness" of screening, the invasiveness of HCC, the multicentric origin, the coexisted Child C cirrhosis, etc., remained great challenge.

Animals↗
PubMed1997

[Properies of orthodontic wires in simulated teeth alignment test]

In this study,methods were developed to test and compare leveling archwires that commonly used in domestic practice.The results showed that the stainless steel arch wires were stiff.The Ni-Ti wires and the wires with loops were flexible and could deliver more constant force.The 0.014 Chinese Ni-Ti wires demonstrated the superelastic property,but 0.016 Ni-Ti wire did not appear the same property before they generated 250g force.

Journal Article↗
PubMed1997

[Orthodontic wires in a simulated oral environment:change in mechanical properties]

In this study,some different kinds of orthodontic archwires were tested to evaluate the changes of their mechanical properties.The results showed that in oral environment,all wires suffered degradation of their properties:the force-generating capacity decreased and the permanent deformation increased.The force-generating capacity decreased and the permanent deformation increased.The force decay resulted mainly from the tooth movement.The deformation occurred within 7 days.Chinese-NiTi alloy suffered less stress-relaxation and residual deformation than the stainless steel wires.Arch wires with vertical loops showed similar properties with NiTi,which could deliver more constant force.

Journal Article↗
PubMed1997

[Determination of organic acids and inorganic anions by gradient ion chromatography].

The chromatographic conditions for separation and detection of organic acids and inorganic anions by gradient ion chromatography with suppressed conductivity detection were studied. The optimized gradient programs were established. Ion chromatography were performed with a DX-100 chromatograph (DIONEX). The separation column is IonPac-AS11. Compared with NaHCO3/Na2CO3 and Na2B4O7, NaOH was the optimal eluent. The effect of organic modifier was also studied. Among methanol, 2-propanol and acetonitrile, methanol can make ion pairs such as malate and succinate, malonate and tartrate gaining baseline resolution. By using ion exchange separation, Cl-, NO3-, malate, succinate, malonate, tartrate, SO4(2-), oxalate were eluted between 5 mmol/L NaOH-16% CH3OH and 10 mmol/L NaOH-16% CH3OH in 25 min. A mobile phase composed of 30 mmol/L NaOH, 50% CH3OH and D.I. water was chosen to elute two groups of organic acids and inorganic anions: (1) quinate, formate, Cl-, malate, malonate, oxalate, citrate, isocitrate, aconitate; (2) lactate, Cl-, SO4(2-), tartrate, PO4(3-), citrate, isocitrate, aconitate. The detection limits (S/N = 3) were 0.1625 (quinate), 0.0691 (formate), 0.0115 (Cl-), 0.0886 (malate), 0.0591 (malonate), 0.0263 (oxalate), 0.1147 (citrate), 0.2017 (isocitrate), 0.3656 (cis-aconitate), 0.1045 (trans-aconitate), 0.1950 (lactate), 0.0729 (tartrate), 0.0224 (SO4(2-)) and 0.0692 (PO4(3-)) mg/L. The relative standard deviations were lower than 11.9% (n = 7) and the correlation coefficients ranged from 0.9212 for Cl- to 0.9999 for formate. The method was applied to determine the organic acids and inorganic anions of beverages and citric acids fermenting-medium. The results were satisfactory.

Anions↗
PubMed1997

Connexin 43 expression in normal and irradiated mouse skin.

The expression of connexin 43 (Cx43) in normal and irradiated mouse skin was evaluated using immunofluorescence with polyclonal antisera to Cx43 on cryostat sections. One week after the start of daily irradiation with 3 Gy, enhanced immunoreactivity in basal cells and in the lower part of the spinous layer of the epidermis was detected. In hypertrophic and hyperplastic skin, about 3 weeks after irradiation, a further increase in the expression of Cx43 was found in the epidermis as well as in the dermis. Western blot analysis of normal and irradiated skin homogenates confirmed the increased Cx43 protein concentration in the skin. In nuclear extracts of the same preparations, increased AP-1-binding activity was found. These data suggest that the gap-junction protein is expressed in response to irradiation of the skin and may be related to the subsequent hyperproliferative response which is associated with accelerated repopulation.

Animals↗
PubMed1997

Lower gastrointestinal tract perforation in preterm infants treated with dexamethasone for bronchopulmonary dysplasia.

Two cases of ileal perforation in preterm infants treated with high-dose dexamethasone for bronchopulmonary dysplasia are described. Corticosteroid-induced gastroduodenal haemorrhage or perforation has been well documented, but less known to most clinicians is that the lower gastrointestinal tract can also be involved. Unlike previous reported cases in which affected infants deteriorated rapidly and became moribund within hours of onset of symptoms, "silent" perforations detected on routine radiograph or escaping clinical recognition until at an advanced stage can be the initial presentation. The need for greater vigilance and a low threshold for abdominal investigations are emphasised in preterm infants treated with dexamethasone.

Anti-Inflammatory Agents↗
PubMed1997

Diagnosis of left atrial thrombus with the aid of transesophageal echocardiography during aortic valve replacement: a case report.

Transthoracic echocardiography and cardiac angiography are the most common tools used in this hospital for evaluation of cardiac disease. Yet the specificity of either method in detection of left atrial pathologies is unsatisfactory. In a 76-year-old male, severe aortic regurgitation with congestive heart failure was impressed from preoperative studies including transthoracic echocardiography and cardiac angiography. However, left atrial thrombus was further detected during routine intraoperative transesophageal echocardiography. Surgical evacuation of a left atrial thrombus was done before undertaking aortic valve replacement. The timely finding was crucial for prevention of further complication and for expeditious use of definite therapy.

Aged↗
PubMed1997

Effect of preoperative transdermal ketoprofen on post-hysterectomy pain.

BACKGROUND: In an attempt to reduce central sensitization after tissue injury, the concept of "pre-emptive analgesia" was evolved. The aim of the present study was to evaluate the analgesic effect of pre-incisional transdermal ketoprofen on post-hysterectomy pain. METHODS: Sixty patients scheduled for elective trans-abdominal total hysterectomy were divided into three groups. The day before surgery, patients in Group 1 received transdermal ketoprofen 30 mg over the proposed surgical area twice; patients in Group 2 received a placebo patch under a similar design; patients in Group 3 received transdermal ketoprofen 30 mg over right thigh twice. Operations were performed under general anesthesia. Postoperatively, patients received patient-controlled analgesia with morphine for pain relief, and pain was assessed by visual analogue pain scale (VAS). Hemodynamic parameters, respiratory rate, sedation scale, morphine consumption and associated side effects were also recorded. RESULTS: There was no significant difference among groups with respect to VAS, sedation scale, blood pressure, respiratory rate or morphine consumption within 24 hours postoperatively. The mean time for first morphine demand was significantly delayed in Group 1 patients (p < 0.05). The incidence of nausea and vomiting among the three groups showed no significant difference. CONCLUSIONS: It seems that pre-incisional transdermal ketoprofen (30 mg, twice the day before surgery) has only a limited pre-emptive effect on post-hysterectomy pain as indicated by delayed first morphine request. Further, it had no effect on postoperative VAS, morphine consumption or incidence of nausea and vomiting.

Administration, Cutaneous↗
PubMed1996

Lipophosphoglycan from Leishmania suppresses agonist-induced interleukin 1 beta gene expression in human monocytes via a unique promoter sequence.

Leishmania are parasites that survive within macrophages by mechanism(s) not entirely known. Depression of cellular immunity and diminished production of interleukin 1 beta (IL-1 beta) and tumor necrosis factor alpha are potential ways by which the parasite survives within macrophages. We examined the mechanism(s) by which lipophosphoglycan (LPG), a major glycolipid of Leishmania, perturbs cytokine gene expression. LPG treatment of THP-1 monocytes suppressed endotoxin induction of IL-1 beta steady-state mRNA by greater than 90%, while having no effect on the expression of a control gene. The addition of LPG 2 h before or 2 h after endotoxin challenge significantly suppressed steady-state IL-1 beta mRNA by 90% and 70%, respectively. LPG also inhibited tumor necrosis factor alpha and Staphylococcus induction of IL-1 beta gene expression. The inhibitory effect of LPG is agonist-specific because LPG did not suppress the induction of IL-1 beta mRNA by phorbol 12-myristate 13-acetate. A unique DNA sequence located within the -310 to -57 nucleotide region of the IL-1 beta promoter was found to mediate LPG's inhibitory activity. The requirement for the -310 to -57 promoter gene sequence for LPG's effect is demonstrated by the abrogation of LPG's inhibitory activity by truncation or deletion of the -310 to -57 promoter gene sequence. Furthermore, the minimal IL-1 beta promoter (positions -310 to +15) mediated LPG's inhibitory activity with dose and kinetic profiles that were similar to LPG's suppression of steady-state IL-1 beta mRNA. These findings delineated a promoter gene sequence that responds to LPG to act as a "gene silencer", a function, to our knowledge, not previously described. LPG's inhibitory activity for several mediators of inflammation and the persistence of significant inhibitory activity 2 h after endotoxin challenge suggest that LPG has therapeutic potential and may be exploited for therapy of sepsis, acute respiratory distress syndrome, and autoimmune diseases.

Animals↗
PubMed1996

Far-infrared VRT spectroscopy of two water trimer isotopomers: vibrationally averaged structures and rearrangement dynamics.

We report the measurement of far-infrared vibration-rotation tunnelling parallel bands of two partially deuterated water trimer isotopomers: (D2O)2DOH and (H2O)2DOH at 97.2607 cm-1 and approximately 86 cm-1, respectively. The hydrogen bond rearrangement dynamics of the two mixed trimers can be described by the simplified molecular symmetry G8, which accounts for both the flipping and bifurcation tunnelling motions previously established for (H2O)3 and (D2O)3. The observed donor tunnelling quartet, rather than triplet, splitting indicates that the two homogeneous monomers (D2O or H2O) in each mixed trimer experience slightly different environments. Vibrationally averaged structures of (H2O)3, (D2O)3, and (D2O)2DOH were examined in a Monte Carlo simulation of the out-of-plane flipping motions of the free atoms. The simulation addresses both the symmetric top behaviour and the negative zero-point inertial defect for (H2O)3 and (D2O)3, which were insufficiently counted in all previous structure models. The average ground state O--O separations, which are correlated to other angular coordinates, were determined to be 2.84 +/- 0.01 angstroms for all three species. The simulated difference in hydrogen bond nonlinearity also supports the inequivalency of the two homogeneous monomers. The structural simulation shows that the unique H in (D2O)2DOH is free, while a torsional analysis suggests the unique D in (H2O)2DOH is bound within the cyclic ring. Both bands can be assigned to the pseudorotational transitions which correlate to those found in the pure trimers.

Chemistry, Physical↗
PubMed1996

Prevalence and identification of abnormal lipoprotein levels in a biracial population aged 23 to 35 years (the CARDIA Study). The Coronary Artery Risk Development in Young Adults Study.

This study examines the prevalence of abnormal low-density lipoprotein (LDL) and high-density lipoprotein (HDL) cholesterol levels in young adults to determine the ability of National Cholesterol Education Program Adult Treatment Panel (ATP) guidelines to identify persons with elevated LDL cholesterol, to compare other algorithms with those of the ATP, and to determine the contributions of race, gender, and other coronary artery disease risk factors to identifying patients with elevated LDL and low HDL cholesterol. The cohort was population-based, aged 23 to 35 years, and included relatively equal numbers of blacks and whites, and men and women. The prevalence of LDL cholesterol > or = 160 mg/dl (> 4.1 mmol/L) was 5% in black women, 4% in white women, 10% in black men, and 9% in white men. ATP identified most participants with elevated LDL cholesterol (range: 58.8% of white men to 70.7% of black women). Lipoprotein panels would have been required in 6% to 7% of women and to 15% to 18% of men. Algorithms that used nonlipid risk factors required more lipoprotein panels and identified fewer additional participants at risk. The prevalence of HDL cholesterol < 35 mg/dl (0.9 mmol/L) was 3% in women, 7% in black men, and 13% in white men. Algorithms that used nonlipid risk factors before measuring HDL cholesterol would require HDL cholesterol measurements in 35% of whites and 56% of blacks, but reduced sensitivity for identifying low HDL cholesterol (range: 58% in white men to 93% in black women). In young adults, algorithms based on nonlipid risk factors and family history have lower sensitivity, and increase rather than decrease the number of fasting lipoprotein panels required when compared with ATP levels.

Adult↗
PubMed1996

cDNA cloning of rasp-1, a novel gene encoding a plasma protein associated with liver regeneration.

We constructed a cDNA library using mRNA isolated from liver 48 hr after hepatectomy (HX) and screened it by differential hybridization using cDNA from normal and regenerating rat liver. We isolated one clone termed regeneration-associated serpin-1 (rasp-1) that was expressed in normal liver but was upregulated approximately 3-4 fold by 48 hr after HX. DNA sequence analysis of rasp-1 indicated that it encoded a novel 436 amino acid secreted protein. Moderate homology was found with several members of the serpin family of serine-protease inhibitors. The 1.7 kb raps-1 mRNA was highly expressed in liver but not in brain, heart, kidney, lung, testis or spleen. We also found the RASP-1 protein in normal and HX rat plasma using a polyclonal antibody generated against a deduced peptide of rasp-1. Rasp-1 may encode a novel serine-protease inhibitor associated with liver regeneration.

Amino Acid Sequence↗
PubMed1996

Human intestinal Vdelta1+ lymphocytes recognize tumor cells of epithelial origin.

gammadelta T cells can be grouped into discrete subsets based upon their expression of T cell receptor (TCR) variable (V) region families, their tissue distribution, and their specificity. Vdelta2+ T cells constitute the majority of gammadelta T cells in peripheral blood whereas Vdelta1+T cells reside preferentially in skin epithelium and in the intestine. gammadelta T cells are envisioned as first line host defense mechanisms capable of providing a source of immune effector T cells and immunomodulating cytokines such as interleukin (IL) 4 or interferon (IFN) gamma. We describe here the fine specificity of three distinct gammadelta+ tumor-infiltrating lymphocytes (TIL) obtained from patients with primary or metastatic colorectal cancer, that could be readily expanded in vitro in the presence of IL-1beta and IL-7. Irrespective of donor, these individual gammadelta T cells exhibited a similar pattern of reactivity defined by recognition of autologous and allogeneic colorectal cancer cells, renal cell cancer, pancreatic cancer, and a freshly isolated explant from human intestine as measured by cytolytic T cell responses and by IFN-gamma release. In contrast, tumors of alternate histologies were not lysed, including lung cancer, squamous cell cancer, as well as the natural/lymphocyte-activated killer cell-sensitive hematopoietic cell lines T2, C1R, or Daudi. The cell line K562 was only poorly lysed when compared with colorectal cancer targets. Target cell reactivity mediated by Vdelta1+ T cells was partially blocked with Abs directed against the TCR, the beta2 or beta7 integrin chains, or fibronectin receptor. Marker analysis using flow cytometry revealed that all three gammadelta T cell lines exhibit a similar phenotype. Analysis of the gammadelta TCR junctional suggested exclusive usage of the Vdelta1/Ddelta3/Jdelta1 TCR segments with extensive (< or = 29 bp) N/P region diversity. T cell recognition of target cells did not appear to be a major histocompatibility complex restricted or to be correlated with target cell expression of heat-shock proteins. Based on the ability of some epithelial tumors, including colorectal, pancreatic, and renal cell cancers to effectively cold target inhibit the lysis of colorectal cancer cell lines by these Vdelta1+ T cell lines, we suggest that intestinal Vdelta1+ T cell lines, we suggest that intestinal Vdelta1+ T cells are capable of recognizing cell surface Ag(s) shared by tumors of epithelial origin.

Amino Acid Sequence↗
PubMed1996

Quantifying hydrogen bond cooperativity in water: VRT spectroscopy of the water tetramer.

Measurement of the far-infrared vibration-rotation tunneling spectrum of the perdeuterated water tetramer is described. Precisely determined rotational constants and relative intensity measurements indicate a cyclic quasi-planar minimum energy structure, which is in agreement with recent ab initio calculations. The O-O separation deduced from the data indicates a rapid exponential convergence to the ordered bulk value with increasing cluster size. Observed quantum tunneling splittings are interpreted in terms of hydrogen bond rearrangements connecting two degenerate structures.

Deuterium Oxide↗