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K Liu

Publications and source records attributed to K Liu.

At least 55 records · Page 3Linked to original sources
PubMed2001

Cutting edge: telomerase activation in human T lymphocytes does not require increase in telomerase reverse transcriptase (hTERT) protein but is associated with hTERT phosphorylation and nuclear translocation.

Capacity for cellular replication is critically important for lymphocyte function and can be regulated by telomerase-dependent maintenance of telomere length. In contrast to most normal human somatic cells that do not express telomerase due to the failure to transcribe telomerase reverse transcriptase (hTERT), lymphocytes express telomerase in a highly regulated fashion yet constitutively transcribe hTERT during development and activation. Here, we report that hTERT protein is present in both thymocytes and blood T cells at equivalent levels despite their substantial differences in telomerase activity, and that induction of telomerase activity in resting CD4(+) T cells is not dependent on net hTERT protein increase. Moreover, hTERT is phosphorylated and translocated from cytoplasm to nucleus during CD4(+) T cell activation. Thus, human T lymphocytes regulate telomerase function through novel events independent of hTERT protein levels, and hTERT phosphorylation and nuclear translocation may play a role in regulation of telomerase function in lymphocytes.

Active Transport, Cell Nucleus↗
PubMed2001

Diagnosis of hematopoietic processes by fine-needle aspiration in conjunction with flow cytometry: A review of 127 cases.

Although fine-needle aspiration (FNA) is accepted as the method of choice for the initial evaluation of lymph nodes for metastatic carcinomas, its utility as the initial diagnostic procedure for hematopoietic processes is less established. We review our experience over a 3-year period with 127 FNA cases accompanied by flow cytometric (FC) analysis from 117 patients. Fifty cases had subsequent histologic examination. A hematopoietic process was identified in 85 cases, a reactive process in 27 cases, and a nonhematopoietic process in 15 cases. All non-Hodgkin lymphomas (NHL) were B-cell processes except for one T-cell lymphoma. By FNA/FC, 44 NHL had sufficient findings to be subtyped; of these, 27 had subsequent histologic examination. The correlation between the FNA/FC and histologic classification in these cases of NHL was 100%. One case was insufficient for diagnosis by FNA and six cases were inadequate for FC. We conclude that FNA in conjunction with FC can be used as the initial diagnostic approach for both primary and recurrent hematopoietic processes.

Biopsy, Needle↗
PubMed2001

Cotton-top tamarins (Saguinus oedipus) fail to show mirror-guided self-exploration.

To investigate the problem of inter- and intraspecific differences on the mirror test, we conducted two experiments on cotton-top tamarins. Experiment 1 employed a technique similar to one used recently on chimpanzees, and provided no evidence of mirror-mediated touching of the marked area. In a control condition, involving colored dye applied to one arm, two subjects also failed to show self-directed touching, even though they clearly looked at their newly dyed arm. Under these test conditions, cotton-top tamarins fail to show mirror-guided self-exploration. Experiment 2 examined whether this failure was due to insufficient mirror exposure, as well as other details of the testing conditions. In particular, we replicated the design of a previously successful experiment on mirror-mediated recognition in tamarins [Hauser et al., 1995], providing four new animals with a protracted period (three weeks) of mirror exposure prior to dying their hair. In parallel with results from Experiment 1, we observed no evidence of mirror-mediated behavior (recognition) in Experiment 2.

Animals↗
PubMed2001

Significance of lymphoglandular bodies in bone marrow aspiration smears.

The presence of lymphoglandular bodies (LGB) or Söderström bodies is often stated to be a feature of lymphoid processes. In our experience, LGB are typically identified in B-cell processes but not in T-cell lymphomas or myeloid leukemias. We reviewed 136 bone marrow aspirate smears. The number of LGB per five high-power fields was counted, and median counts for B-cell processes, non-B-cell processes, myeloid leukemias, and T-cell malignancies were obtained and compared by the Wilcoxon rank sum test. Bone marrow aspirate smears involved with B-cell malignancies contained a median of 30 (range, 1-250) LGB per five high-power fields. Compared to myeloid leukemias (median, 11; range, 1-253) and T-cell malignancies (median, 7; range, 0-41), the differences were statistically significant (P < 0.001 and P = 0.01, respectively). While lymphoglandular bodies can be seen in a variety of malignant hematopoietic and nonhematopoietic disorders, they are found in significantly greater numbers in B-cell malignancies.

Biopsy, Needle↗
PubMed2001

Atypical squamous epithelium in cytologic specimens from the pancreas: cytological differential diagnosis and clinical implications.

Atypical squamous epithelium is an uncommon finding in cytologic specimens obtained from pancreatic lesions. A variety of pathologic conditions can result in the presence of these cells, including primary or metastatic carcinomas, chronic pancreatitis, and squamous metaplasia related to pancreatic or biliary duct stent placement. Primary adenosquamous and squamous-cell carcinomas of the pancreas are rare, representing 3.4% and 1.4 % of pancreatic carcinomas, respectively. Cytologic separation of these malignancies from less ominous metaplasias has immense clinical importance. We reviewed Indiana University Hospital's and Duke University's experiences with atypical squamous epithelium occurring within pancreatic aspirates. Study cases were identified using a computer to search the cytology records of these two institutions. Nine cases with a diagnosis of squamous-cell carcinoma, adenosquamous carcinoma, or atypical squamous epithelium were retrieved from the two institutions' Department of Pathology files. One case of pure squamous-cell carcinoma occurred in a patient with a known pulmonary primary; a single case of adenosquamous carcinoma was diagnosed in a patient with a coexistent endometrial primary; a single sample of adenocarcinoma with squamous differentiation was diagnosed in a patient without other known disease; and four primary squamous-cell carcinomas of the pancreas were detected. In addition, a single case of atypical squamous metaplasia associated with a stent was identified, and one case of atypical squamous epithelium associated with chronic pancreatitis was diagnosed. Despite the reactive atypia present in the examples of metaplastic squamous epithelium, separation of these cases from true squamous-cell carcinoma and adenosquamous carcinoma was achievable by cytologic evaluation. No cytologic criteria aided in separating primary pancreatic carcinomas with squamous differentiation from metastatic lesions. In this study, we report our findings in a series of nine cases where cytology disclosed atypical squamous epithelium in the aspirates derived from pancreatic lesions.

Carcinoma, Adenosquamous↗
PubMed2001

SB203580 promotes EGF-stimulated early morphological differentiation in PC12 cell through activating ERK pathway.

MAP kinases have important role in PC12 cell differentiation, since the activities of both extracellular regulated protein kinase (ERK) and p38 have been indicated as necessary signal for PC12 cell differentiation. Epidermal growth factor (EGF) and NGF both activate ERK and p38 in PC12 cells, but only NGF trigger differentiation. It has been proposed that the duration of ERK activation determines the switch from proliferation to differentiation, since EGF causes more transient activation of ERK than NGF in PC12 cells. Here we report that treatment of PC12 cells with EGF in the presence of SB203580, a widely used p38 inhibitor, caused differentiation. The pro-differentiation effect of SB203580 in EGF-treated PC12 cells was found to be independent of its function of p38 inhibition but was through an effect on the ERK pathway that has been recently reported (Kalmes et al. [1999] FEBS Lett. 444: 71-74; Hall-Jackson et al. [1999] Onc. 18: 2047-2054). We found that SB203580 by itself did not affect the activity of ERK1/2 but significantly extended EGF-induced ERK activation in PC12 cells, which resulted in early morphological differentiation. Our data indicated that although both ERK and p38 are required for PC12 cell differentiation, activation of p38 is not required when ERK is superactivated. Our data provided further evidence for the threshold theory that differentiation is determined by the duration of ERK activation.

Adenoviridae↗
PubMed2001

Intrathecal bupivacaine with morphine or neostigmine for postoperative analgesia after total knee replacement surgery.

PURPOSE: To compare the postoperative analgesic efficacy and safety of intrathecal (IT) neostigmine and IT morphine in patients undergoing total knee replacement under spinal anesthesia. METHODS: Sixty patients scheduled for elective total knee replacement under spinal anesthesia were randomly divided into three equal groups which received IT 0.5% hyperbaric bupivacaine 15 mg with either normal saline 0.5 mL, neostigmine 50 microg, or morphine 300 microg. The maximal level of sensory block, duration of analgesia, time to use of rescue analgesics, the overall 24-hr and four-hour interval visual analogue scale (VAS) pain score, and the incidence of adverse effects were recorded for 24 hr after administration. RESULTS: There was no significant difference in maximal level of sensory block among the three groups. The morphine group had a later onset of postsurgical pain and longer time to first rescue analgesics than the neostigmine group (P <0.05). Overall 24-hr VAS pain scores were significantly higher in the saline group vs the morphine and neostigmine groups (P <0.05). Motor block lasted significantly longer in the neostigmine group than in the morphine and saline groups (P <0.05). The incidence of adverse effects was similar in the neostigmine and morphine groups except for pruritus (70%) occurring more frequently in the morphine group than in the neostigmine and saline groups (0%; P <0.05). Overall satisfaction rates were better in the neostigmine group than in the morphine and saline groups (P <0.05). CONCLUSIONS: IT neostigmine 50 microg produced postoperative analgesia lasting about seven hours with fewer side effects and better satisfaction ratings than IT morphine 300 microg.

Aged↗
PubMed2001

Oats and soy in lipid-lowering diets for women with hypercholesterolemia: is there synergy?

OBJECTIVES: To study possible synergistic effects of oats and soy on reducing total and low-density lipoprotein cholesterol (LDL-C) concentrations in human beings and the efficacy and feasibility of including these adjustments to a National Cholesterol Education Program Step I diet. SUBJECT/SETTING: One hundred twenty-seven postmenopausal women with moderate hypercholesterolemia were recruited from a large Midwestern workforce and senior centers in the surrounding community. Intervention and clinical visits were conducted in these same facilities. DESIGN: After a 3-week lead-in period on the Step I diet, participants were randomly assigned to 1 of 4 dietary treatments for an additional 6 weeks: an oats/milk group, a wheat/soy group, an oats/soy group, and a wheat/milk group. Clinical measurements included blood draws, body weight and height, blood pressure, and medical history data. Three-day food records were collected at baseline and Weeks 3 and 9 of the intervention. Randomization was stratified based on the status of hormone replacement therapy and was blocked with sizes 4 or 8 for group assignment. RESULTS: After 3 weeks on the Step I diet, total cholesterol, LDL-C, and triglyceride levels; total fat and saturated fat intake, dietary cholesterol intake, Keys score, and body mass index were all reduced. Following an additional 6 weeks on the Step I diet plus intervention, total cholesterol and LDL-C were further reduced for both the oats/soy group and oats/milk group. There were no significant further changes in total cholesterol, LDL-C, or high-density lipoprotein cholesterol levels in the wheat/soy and wheat/milk groups. Body mass index remained stable in all groups from Week 3 to Week 9. APPLICATIONS: Nonpharmacologic dietary interventions like the Step I diet are feasible in a community setting and can produce rapid and significant lipid-lowering benefits. Daily consumption of 2 servings of oats can contribute to further lipid alterations in this population although soy intake at this dose may not. Palatability and convenience are important considerations in achieving dietary adherence.

Aged↗
PubMed2001

A randomized trial of zinc nasal spray for the treatment of upper respiratory illness in adults.

PURPOSE: We performed a randomized, double-blind, placebo-controlled trial to evaluate the efficacy of 0.12% zinc sulfate nasal spray for reducing the duration and severity of acute upper respiratory infections. SUBJECTS AND METHODS: Patients with acute onset of upper respiratory illness of less than 24 hours' duration were eligible for the study. A nasopharyngeal swab was obtained at the time of enrollment for viral culture. Participants were randomly assigned to receive either 0.12% zinc sulfate or isotonic placebo spray. The medication was administered as two inhalations in each nostril four times a day. Each patient completed a diary card twice a day to record oral temperature, symptoms, and adverse effects. Symptoms were scored as absent (0), mild (1), moderate (2), or severe (3). RESULTS: One hundred eighty-five subjects volunteered to participate, and 160 met the criteria for enrollment. The median duration of all symptoms was 7 days in both groups (P = 0.45), and the median duration of nasal symptoms was 6 days in both groups (P= 0.12). After adjustment for baseline differences in severity, patients receiving zinc had a significant reduction in the total symptom score (P= 0.02) and the nasal symptom score (P= 0.02) on day 1, but not on any of the other days. Adverse effects were mild and had no significant association with the use of zinc. A respiratory virus was identified in 9 of the 160 participants; 6 of these were rhinovirus. CONCLUSION: A low concentration of zinc sulfate nasal spray had no effect on the duration of the common cold.

Acute Disease↗
PubMed2001

PG490-88, a derivative of triptolide, blocks bleomycin-induced lung fibrosis.

In this study we evaluate the antifibrotic properties of PG-490-88, a water-soluble derivative of triptolide. Triptolide is an oxygenated diterpene that is derived from a traditional Chinese herb that has potent immunosuppressive and antitumor activity. We used the intratracheal bleomycin mouse model and found that PG490-88 inhibits fibrosis in the bleomycin group when given the same day or 5 days after bleomycin. PG490-88 also markedly reduced the number of myofibroblasts in the bleomycin treatment group. An enzyme-linked immunosorbent assay of transforming growth factor (TGF)-beta in the bronchoalveolar lavage fluid showed a significant decrease in TGF-beta in the PG490-88-treated groups compared to the bleomycin-treated group. Additionally, triptolide blocked bleomycin-induced increase in TGF-beta mRNA in cultured normal human lung fibroblasts. The efficacy of PG490-88 when administered late after bleomycin installation suggests a potential role in the treatment of idiopathic pulmonary fibrosis.

Animals↗
PubMed2001

Multiple contrast fast spin-echo approach to black-blood intracranial MRA: use of complementary and supplementary information.

Black-blood magnetic resonance angiography (black-blood MRA) could be considered an alternative to time-of-flight (TOF) MRA. In the cases of irregular flow conditions, it could be more advantageous than time-of-flight (TOF) MRA in providing vessel definition and delineation. Proton-density weighted (PDW) multi-slab three-dimensional fast spin-echo (3DFSE) sequences have been used to generate black-blood MRA. Unfortunately, multi-planar reformatted 3DFSE images often exhibit slab boundary artifacts (intensity variation in the slice direction) which create dark bands interfering with the identification of dark blood vessels. Furthermore, PDW measurements fail to darken slow flowing or re-circulating blood in some circumstances. In this work, a dual-contrast multi-slab 3DFSE acquisition is used to approach black-blood MRA. This sequence simultaneously provides proton-density weighted (PDW) and T(2)-weighted (T2W) images which can be further integrated together to produce black-blood angiograms gained by utilizing complementary contrast and supplementary vascular information. Additionally, a technique of suppressing slab boundary artifact has been incorporated into this sequence. This approach provides: i) good SNR measurement of anatomy for the PDW image and optimal black-blood angiograms from the T2W image; ii) scan time efficiency (dual-contrast image sets plus black-blood angiograms within one acquisition); and iii) suppressed slab boundary artifacts as well as minimized mis-registration error.

Algorithms↗
PubMed2001

Kinetics of tumorigenic vascular endothelial growth factor signalling and its significance in human hepatocellular carcinoma cells.

Ras-VEGF-concerned angiogenesis is correlated with oncogene maintenance, tumorigenesis, metastasis and resistance to anti-cancer therapies; however, this association is not clearly elucidated by serum VEGF, due to VEGF signalling in blood cells themselves. The present study aimed to elucidate tumorigenic VEGF signalling in eight human HCC cell types and reveal the kinetics of tumorigenic VEGF signalling in three time intervals, thereby discovering the relationships of VEGF-concerned angiogenesis signalling with the extent of the human HCC cell growth, metastasis and resistance to anti-cancer drugs, by using the poorly metastatic SMMC7721, 7402/D+ (doxorubicin-resistance) and 7402/D- (doxorubicin-withdrawal), the highly metastatic MHCC1 non-transfected human HCC cell lines, and the highly metastatic A3-1, F8, F11 and E3 human HCC cell lines transfected with expressing green fluorescence protein into the phenotype of MHCC1 cells, and quantitative 'sandwich' ELISA analyses. The unique results indicated attributes and objective laws as follows. Human HCC cell growth requires time-dependent tumorigenic VEGF signalling; levels of VEGF signalling are positively correlated with each cell phenotype itself; and levels of VEGF signalling are inversely correlated with the possibility of metastasis and drug resistance. The contrast data first reveal important clues for exploring dual metastatic mechanisms via tumor cell-generated non-endothelium vasculogenesis and VEGF-endothelium-attached angiogenesis that may be essential for developing novel strategies aimed at VEGF-concerned signal networks in ischemic/metastatic diseases and transgenic models.

Carcinoma, Hepatocellular↗
PubMed2001

Independent and interactive effects of apolipoprotein E phenotype and cardiorespiratory fitness on plasma lipids.

PURPOSE: To examine whether the association Apolipoprotein E (Apo E) phenotype with plasma lipids is influenced by physical fitness level. Also, to explore the interactive and independent relative contributions of Apo E phenotype, fitness (or physical activity), and other modifiable factors to variation in plasma low density lipoprotein (LDL-C) and high density lipoprotein (HDL-C) levels at baseline and over a seven-year follow-up. METHODS: Physical fitness (duration of a graded treadmill test), Apo E phenotype, plasma LDL-C and HDL-C, and covariates were measured at baseline and seven years later in a bi-racial cohort of young adults, aged 18-30 years at baseline in 1985-86, from the Coronary Artery Risk Development In Young Adults (CARDIA) study. RESULTS: Fitness did not influence the associations of Apo E and LDL-C or HDL-C. The independent effects of several modifiable variables (changes in Keys' score, smoking, oral contraceptive use, education, body weight, alcohol intake, and fitness), when combined, contributed considerably more than Apo E to the variance in LDL-C changes (6.74% or 8.71% for combined modifiable variables vs. 1.27% or 0.90% for ApoE, in women or men, respectively) and HDL-C changes (13.11% or 12.66% for combined modifiable variables vs. 0.12% or 0.02% for ApoE, in women or men, respectively). The pattern of findings was similar when self-reported physical activity was substituted for fitness. CONCLUSIONS: Changes in modifiable factors, including fitness, may be stronger correlates of changes in LDL-C and HDL-C over time than the immutable factor, Apo E phenotype.

Adolescent↗
PubMed2001

Delineating the genetic basis of systemic lupus erythematosus.

Genetic predisposition plays a crucial role in susceptibility to systemic lupus erythematosus (SLE) in both human patients and animal models. Recent progress in experimental systems and human linkage analysis is providing key insights into the genetic basis for susceptibility and elucidating the manner in which genetic interactions mediate severe disease pathogenesis. Genes in multiple pathways appear to participate in specific elements of the disease, and epistatic interactions among these genes play an important role in both aggravating and suppressing disease development.

Autoimmunity↗
PubMed2001

Postload plasma glucose concentration and 27-year prostate cancer mortality (United States).

OBJECTIVE: Findings from epidemiologic studies on the association between diabetes and prostate cancer risk are inconsistent. However, data from at least three studies suggest that the direction and strength of this association differs according to duration of diabetes. To determine the potential effects of early-stage abnormal glucose metabolism on risk, we assessed the relationship of postload glycemia in the absence of self-reported diabetes with risk of prostate cancer mortality. METHODS: Data from the Chicago Heart Association Detection Project in Industry were used to examine this relationship. Between 1967 and 1973 some employees of 84 Chicago area organizations underwent a health screening examination. Blood was drawn for measurement of plasma glucose concentration approximately 1 h after a 50-g oral glucose load among 20,433 men. After a mean length of follow-up of 27 years, 176 men died of prostate cancer. Cox regression was used to compute adjusted relative risks (RRs) and 95% confidence intervals (CIs). RESULTS: After controlling for age, body mass index, heart rate, education, and race, the RRs of prostate cancer mortality for postload plasma glucose levels of 6.7-8.8, 8.9-11, and > or = 11.1 mmol/L compared to < or = 6.6 mmol/L were 1.64, 1.37, and 1.64. respectively (p for trend=0.19). The RR (95% CI) associated with a 2.2 mmol/L (1 standard deviation) higher glucose concentration was 1.1 (0.95-1.2). CONCLUSIONS: These results provide weak evidence of an association between hyperglycemia and prostate cancer mortality.

Administration, Oral↗
PubMed2001

Modification of fibroblast gamma-interferon responses by extracellular matrix.

Fibroblasts from scaffold-based three-dimensional human cultures have been demonstrated to colonize ulcer wound beds and persist for at least 6 mo without rejection. This study examines the expression in these cultures of molecules associated with activation of the immune system in acute rejection. Studies in monolayer cultures showed that fibroblasts expressed CD40 at about 10% of the surface density seen in umbilical vein endothelial cells, whereas HLA-DR was undetectable. In these cultures, both molecules were induced by gamma-interferon. In scaffold-based three-dimensional cultures, however, a majority of the fibroblasts showed little induction of CD40 and HLA-DR in response to gamma-interferon, although HLA class I expression was increased. Fibroblasts re- isolated from the three-dimensional cultures and cultured in monolayers recovered HLA-DR induction in response to gamma-interferon. Fibroblasts cultured in an alternative three-dimensional system using collagen gels showed CD40 and HLA-DR induction by gamma-interferon in the same manner as monolayer cultures. Comparison of phosphorylation of signal transducer and activator of transcription 1 on tyrosine-701 showed it to be similar in monolayer and three-dimensional culture, and phospho-signal transducer and activator of transcription 1 moved into the nucleus. Induction of the class II transcription activator was greatly reduced, however. We propose that interaction of fibroblasts with the fibroblast-derived extracellular matrix is an important modulator of gamma-interferon responsiveness and that this interaction may play a role in the low immunogenicity of allogeneic fibroblasts grown on scaffolds.

Antigens, CD↗
PubMed2001

Prevalence and significance of unrecognized lower extremity peripheral arterial disease in general medicine practice*.

OBJECTIVE: To determine the prevalence of unrecognized lower extremity peripheral arterial disease (PAD) among men and women aged 55 years and older in a general internal medicine (GIM) practice and to identify characteristics and functional performance associated with unrecognized PAD. DESIGN: Cross-sectional. SETTING: Academic medical center. PARTICIPANTS: We identified 143 patients with known PAD from the noninvasive vascular laboratory, and 239 men and women aged 55 and older with no prior PAD history from a GIM practice. Group 1 consisted of patients with PAD consecutively identified from the noninvasive vascular laboratory (n = 143). Group 2 included GIM practice patients found to have an ankle brachial index less than 0.90, consistent with PAD (n = 34). Group 3 consisted of GIM practice patients without PAD (n = 205). MEASUREMENTS AND MAIN RESULTS: Leg functioning was assessed with the 6-minute walk, 4-meter walking velocity, and Walking Impairment Questionnaire (WIQ). Of GIM practice patients, 14% had unrecognized PAD. Only 44% of patients in Group 2 had exertional leg symptoms. Distances achieved in the 6-minute walk were 1,130, 1,362, and 1,539 feet for Groups 1, 2, and 3, respectively, adjusting for age, gender, and race (P <.001). The degree of difficulty walking due to leg symptoms as reported on the WIQ was comparable between Groups 2 and 3 and significantly greater in Group 1 than Group 2. In multiple logistic regression analysis including Groups 2 and 3, current cigarette smoking was associated independently with unrecognized PAD (odds ratio [OR], 6.82; 95% confidence interval [95% CI], 1.55 to 29.93). Aspirin therapy was nearly independently associated with absence of PAD (OR, 0.37; 95% CI, 0.12 to 1.12). CONCLUSION: Unrecognized PAD is common among men and women aged 55 years and older in GIM practice and is associated with impaired lower extremity functioning. Ankle brachial index screening may be necessary to diagnose unrecognized PAD in a GIM practice.

Age Factors↗