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Biomedical subjects

F J Liu

Publications and source records attributed to F J Liu.

At least 19 recordsLinked to original sources
PubMed2005

A novel method to make regenerable core-shell calcium-based sorbents.

A sorbent having a calcium oxide core and a clay shell was prepared and shown to be capable of reusable applications in absorption and desorption processes for carbon dioxide. The novelty of this sorbent is that only calcium carbonate and clay are used for its preparation with water as a binder. A two-step granulation procedure is used to get the core and then another step to coat the shell layer with the clay powder. A repeated wet-and-dry procedure probably makes the core porous yet strong enough to serve as a sorbent. The pellet is then calcined at 1200 degrees C for 2h to reach its final structure. The core-shell pellets have an overall diameter of 4.4mm with average shell thickness of 0.45 mm, crush load of 35 N and attrition index of 0.035 wt%/h. These results indicate that the pellets will probably be capable of withstanding the stress in future applications. Carbon dioxide absorption at or below 300 degrees C showed a maximum weight gain of 38% for our pellets. Finally, desorption in nitrogen at 800 degrees C can restore the pellet to its original state and hence it is ready for re-use as a sorbent.

Absorption↗
PubMed2003

Echinococcosis on the Tibetan Plateau: prevalence and risk factors for cystic and alveolar echinococcosis in Tibetan populations in Qinghai Province, China.

Infections by larval stages of tapeworms of the genus Echinococcus (echinococcosis or hydatid disease) are zoonotic infections of major public health importance throughout much of the world. Humans become infected through accidental ingestion of eggs passed in faeces of canid definitive hosts. Tibetan populations of China have some of the highest documented levels of infections by both Echinococcus granulosus and E. multilocularis, the causes of cystic and alveolar echinococcosis, respectively. In this study we measured the prevalence of cystic (CE) and alveolar (AE) echinococcosis disease in Tibetan communities in Qinghai, Province, China, and identified putative risk factors for both infections in these communities. 3703 volunteers in three predominately Tibetan counties of Qinghai were surveyed between June 1997 and June 1998. Parasitic lesions were diagnosed by imaging of characteristic space-occupying lesions in abdominal organs (ultrasound) or the lungs (radiographs). Specific serodiagnostic assays (Dot-ELISA and Em2-ELISA) were performed on sera of positively imaged subjects to further distinguish the disease agent. All participants completed a questionnaire documenting age, sex, education level, occupation, lifestyle (nomadic or settled), slaughter practices, drinking water source, hygienic practice and association with dogs. Data were analyzed using SAS version 8. 6.6% of the volunteers had image-confirmed infection with E. granulosus (CE) and 0.8% had E. multilocularis (AE) infection. The significant univariate factors for echinococcal infection (both CE and AE) included livestock ownership, Tibetan ethnicity, female gender, low income, herding occupation, limited education, water source, age greater than 25 years old, poor hygienic practices, offal disposal practices and dog care. Multivariate analysis revealed that livestock ownership was a significant risk factor for both forms of the disease, as well as age greater than 25 years, female gender, herding occupation, and being nomadic (vs semi-nomadic or settled). No additional significant risk factors were identified among the 344 nomadic participants. Being female and being older than 25 years of age were significant factors among the 1906 semi-nomadic participants. Among the 1445 settled participants, allowing dogs to sleep indoors was statistically significant. Issues such as inadequate assessment of animal ownership, selection bias, disease misclassification, and loss of information may have led to reduction in strength of some risk factor associations and need to be addressed in future epidemiologic analysis of echinococcosis in this population.

Adolescent↗
PubMed2001

Investigation of risk factors for development of human hydatidosis among households raising livestock in Tibetan areas of western Sichuan province.

OBJECTIVE: To identify factors influencing the development of hydatidosis in Tibetan areas of western Sichuan. METHODS: A questionnaire investigation was carried out to collect data on factors related to hydatidosis among households raising livestock. RESULTS: Analyses of data revealed that dogs rather than foxes were the most important source of AE transmission. People below 19 years old tended to suffering from CE rather than AE and people 19-38 years old, especially the females, were under an increasing risk of suffering from AE (female vs. male, OR = 2.438, CI = 1.317-4.514, P < 0.05). Increased risks of both AE and CE prevalence associated with nomadic life, aging, playing with dogs, not protecting food from flies, and raising yaks or sheep. CONCLUSION: In addition to age, sex, environmental conditions and hygienic behaviors, raising yaks or sheep and playing with dogs also increase the risk of suffering from hydatidosis as well in this area.

Adolescent↗
PubMed2000

Lactate dehydrogenase isoenzyme 1 is the most important LD isoenzyme in patients with testicular germ cell tumor.

We examined the clinical utility of serum lactate dehydrogenase (LD) isoenzyme catalytic concentrations in 58 patients with testicular germ cell tumors (TGCT) (13 with seminoma and 45 with non-seminomatous tumors). Twenty-one patients with no evidence of disease (NED) all had serum LD isoenzyme 1 catalytic concentrations (LD-1) and LD-1/LD fractions below the upper limit of the reference values (ULR). LD-1 and the LD-1/LD fraction discriminated significantly between evidence of disease (ED) and NED (p = 0.00009 and p = 0.028, respectively, Mann Whitney U-test). Twenty of the 37 patients with ED had raised values of LD-1. The 17 patients with an LD-1 < 1.0 x ULR had a better survival than the 10 patients with LD-1 between 1.0 and 2.9 x ULR, the 7 with LD-1 between 3.0 and 5.9 x ULR, and the 3 patients with LD-1 > 6.0 x ULR (p = 0.006, log-rank test, chi2 test for trend)). Twenty-three patients with an LD-1/LD fraction < or = 0.25 had a better survival than the 14 with an LD-1/LD fraction > 0.25 (p = 0.013). Nineteen patients with LD-5 < 105 U/L and the 15 with LD-5 > 105 U/L had a similar rate of survival (p = 0.85). Our findings add to the evidence showing LD-1 in preference to LD as a serum tumor marker of TGCT.

Adolescent↗
PubMed1998

Pycnogenol enhances immune and haemopoietic functions in senescence-accelerated mice.

Pycnogenol (procyanidin extracted from Pinus maritima) has been shown to be a potent free radical scavenger and an antioxidant phytochemical. The effects of pycnogenol on immune and haemopoietic dysfunction in senescence-accelerated mice (SAM), as a murine model of accelerated ageing, were determined. SAMP8, a strain of senile-prone mice, exhibit learning and memory deficits, immunodeficiency and dysfunction of the haemopoietic system. Oral feeding with pycnogenol for 2 months significantly improved their T- and B-cell function. Pycnogenol also augmented the proliferative capacity of haemopoietic progenitors of bone marrow in SAMP8. These data suggest that pycnogenol may be useful for either retardation or restoration of parameters associated with ageing.

Aging↗
PubMed1998

ERPs of characters of Chinese words compared with tone and picture stimuli in adolescents and aged persons.

ERPs to target stimulation with tone, picture and characters of Chinese words ([symbol: see text] CCW were target stimulus) were studied in adolescents group and aged persons group. The age of the adolescent group ranged from 15-17 years, with 30 males and 30 females; the age of the elderly persons group ranged from 60-79 years with 29 males and 18 females. The latencies of N2 of aged persons in tone stimulus and in picture stimulus among males were longer than those of adolescents. The latencies of P3 and RT of aged persons were longer than those of adolescents in three stimulus models. The gender differences of latencies of N2 and RT were not obvious in two groups, but were apparent in P3 in adolescents. The latencies of N2, P3 and RT of CCW stimulus were longer compared to those of picture stimulus in the adolescent group, but not in the aged persons group.

Adolescent↗
PubMed1997

[The study and manufacture of spinning counter for experimental animals].

The single-chip microcomputer technique is used in the present study of spinning counter, which has 4 observation tunnels, the spinning behave of four experiment animals can be recorded at same time. The function of this instrument has four selections according to different experiment, and the recording data can be compute processed.

Animals↗
PubMed1997

Molecular study of hairy cell leukemia variant with biclonal paraproteinemia.

We report an unusual case of hairy cell leukemia variant with IgA and IgG-lambda biclonal gammopathy exhibiting light chain and a surface immunoglobulin class different from that of the paraproteins. In addition, we documented by gene rearrangement study that the hairy cell leukemia variant clone appears independent from the paraprotein-producing cells. The kappa light chain was expressed on the surface of hairy cell leukemia variant cells. Southern blot analysis revealed rearrangement of the kappa-light-chain gene and germline configuration of lambda-light-chain gene. We observed significant clinical improvement and reduction in the leukemic infiltrate in the patient after treatment with 2-chlorodeoxyadenosine (2-CdA). The intensity of the rearranged kappa-light-chain gene band decreased with therapy and increased at relapse without significant change of the paraproteins. Previously reported cases of hairy cell leukemia variant with paraproteins are reviewed, and our patient's contribution to the understanding of this association is stressed.

Aged↗
PubMed1995

Laparoscopic exploration of intra- and extrahepatic bile ducts and T-tube drainage.

Laparoscopic cholecystectomy (LC) has rapidly become the procedure of choice for the management of patients with gall-bladder stones. This contrasts with patients who have common bile duct and intrahepatic duct stones who still usually need an open operation. On the basis of experience of a number of LC by one surgeon and animal experiments, we have completed laparoscopic exploration of both intra- and extrahepatic ducts and T-tube drainage of 57 patients with intra- and extrahepatic bile duct calculi over 13 months during 1992-1993 with satisfactory results. The average operating time was 150 min, with a range of 100 to 220 min. Most patients were mobile and on oral fluids within 24 h postoperative. Average hospital stay was 4 days. Retained stones were found via T-tube cholangiography in four patients (7%) and for each patient these were removed by fibre-optic choledochoscope 2 weeks postoperatively. Laparoscopic exploration of intra- and extrahepatic bile ducts is achievable by experienced surgeons and may be particularly helpful for patients who are not a good operative risk.

Adult↗
PubMed1993

Serologic determinants of survival in patients with head and neck cancer: validating a clinical prediction model.

Quantitative measurements of serum C1q-binding macromolecules (C1qBM) and immunoglobulin A (IgA) were done on 162 patients using previously described methodology. The measurements were compared to a previously described head and neck cancer population. Using the Cox Proportional Hazards model, the prognostic implications regarding high C1qBM and subsequent death with disease (P = .02), and regional recurrence (P = .0094) were validated, but not our previous IgA-related prognostic implications. When both study populations were combined, C1qBM was predictive of survival in those patients treated with induction chemotherapy (P = .0001). C1qBM was not a significant predictor of survival in patients treated with surgery plus postoperative radiation therapy in either this second "test" population or in the original "training" population. The findings demonstrate the confounding influence of treatment modalities and the importance of model validation.

Age Factors↗
PubMed1993

Serum and acute phase protein modulation of the effector phase of lymphokine-activated killer cells.

An understanding of the role that immunomodulatory factors play in the effector phase of lymphokine-activated killer (LAK) activity is essential for the development of biologic response modifiers for use in the treatment of advanced carcinoma. Fifteen head and neck cancer patients were studied. Single-donor killer cells activated by recombinant interleukin-2 (10 U/mL) and induced in either a complete medium or complete medium plus a 10% autologous serum solution were used. Effector phase solutions of 25% autologous serum were used in chromium 51 release assays to determine sera immunomodulation of LAK cell cytotoxicity. Both K562 and squamous carcinoma (MDA686-Ln) tumor cell lines were tested. Significant effector phase inhibition (EPI) of cytotoxicity occurred in 40% of studied patients. Seventy percent of patients with stage III or IV or recurrent disease exhibited EPI, whereas only 20% of patients with stage I or II disease and 30% of controls did so. EPI of cancer patient serum correlated directly with alpha 1-antitrypsin, alpha 1-acid glycoprotein, and C-reactive protein (CRP) levels (MDA686-Ln targets) (r = 0.6, 0.7, and 0.6, respectively) (P < .02). Neither EPI against K562 targets nor EPI in control patients correlated with acute phase protein levels. These findings suggest that advances in in vivo immunomodulatory therapy will be dependent upon further elucidation of serologic inhibition of the effector phase of the LAK cell phenomenon. The relationship between LAK cell recognition and EPI requires further investigation.

Acute-Phase Proteins↗
PubMed1992

Acute-phase proteins in patients with head and neck cancer treated with interleukin 2/interferon alfa.

Circulating acute-phase proteins may mediate adverse reactions in patients receiving biologic response modifiers, including inhibition of immune responsiveness and clinical toxic effects. Nine patients with unresectable head and neck squamous cell carcinoma were prospectively examined for levels of acute-phase proteins during interleukin 2/interferon alfa immunotherapy and for clinical toxic effects. Simultaneous determination of the in vitro immunomodulatory capacity of autologous serum on the induction of lymphokine-activated killer cells was assessed in 4-hour chromium release assays. Of the seven acute-phase proteins analyzed, haptoglobin and C-reactive protein levels were elevated before therapy was started. Toxic events leading to cessation of interleukin 2/interferon alfa therapy had a high correlation with elevated C-reactive protein and lowered C3 component of complement levels. No relationship was noted between serum levels of acute-phase proteins and induction inhibition of lymphokine-activated killer cell cytotoxicity. The role of C-reactive protein and complement degradation products in mediating interleukin 2/interferon alfa toxicity requires further investigation.

Acute-Phase Proteins↗
PubMed1992

Epidemiology of measles immunity in a population of healthcare workers.

OBJECTIVE: To evaluate epidemiologic factors that can be used to predict lack of measles immunity in healthcare workers. DESIGN: During mandatory screening of employees for measles antibody, a questionnaire was used to collect demographic information. SETTING: Inpatient hospital, acute care clinics, and skilled nursing facility of a health maintenance organization. PARTICIPANTS: Employees of all ages and occupations. RESULTS: Measles immunity could not be predicted from history of measles disease and vaccination, gender, or birthplace. Of nonimmune employees, 63.7% were in the 20- to 29-year-old age group and 26.5% were in the 30- to 39-year-old age group. CONCLUSIONS: Age is the most clinically significant predictor of measles antibody, especially in persons born after 1950, who make up a large group susceptible to measles.

Adolescent↗
PubMed1991

Serum biomarkers in metastatic renal cell carcinoma.

To identify possible clinically valuable markers of metastatic renal cell carcinoma, we measured the serum concentrations of several commercially available biomarkers in 117 patients with this disease. The alpha-fetoprotein level was measured in 75 patients and was elevated in 8 (11%); elevation did not correlate with the presence of liver metastasis. Beta subunit of human chorionic gonadotropin levels increased in 8 of 83 patients tested (10%). C-terminal parathyroid hormone levels were measured in 79 patients and were elevated in 15 (19%); their serum creatinine level was normal. Thirteen of this group had normal serum calcium levels, whereas 7 patients with hypercalcemia and no clinically evident bone metastasis had normal parathyroid hormone levels. In only 2 of 72 patients, serum lactate dehydrogenase and its isoenzyme 1 were elevated. Only 1 of 85 patients had mildly elevated serum carcinoembryonic antigen, in contrast to 3 of 7 patients with metastatic transitional cell carcinoma of the renal pelvis who had moderately elevated carcinoembryonic antigen. Elevations in alpha-fetoprotein, human chorionic gonadotropin, and parathyroid hormone correlated with the course of the disease in 13 patients for whom follow-up measurements were available; measurement of these markers, however, is only useful in a small proportion of patients with metastatic renal cell carcinoma.

Biomarkers, Tumor↗
PubMed1991

Serum lactate dehydrogenase-3 isoenzyme in chronic granulocytic leukemia.

Abnormal levels of serum lactate dehydrogenase-3 (LD-3) activity were observed in 92% of patients (35 of 38) with active chronic granulocytic leukemia (CGL), in 40% of patients (4 of 10) in partial remission, and in 13% of patients (1 of 8) in complete remission. In evaluating the electrophoretic LD isoenzyme patterns of these patients, three criteria were used. In criterion-1 elevations, the LD-3/total LD ratio, expressed as a fraction of serum total LD, and LD-3 value, expressed in absolute units, were greater than the upper limit of the reference range. In criterion-2 elevations, only the LD-3/total LD ratio was greater than the upper limit of the reference range. In criterion-3 elevations, only the absolute LD-3 activity exceeded the upper limit of the reference range, and these specimens showed isomorphic elevation of all five LD isoenzymes. Use of the last of these criteria increased the clinical sensitivity of serum LD-3 elevations in active CGL from 82% to 92%. The mean serum LD-3 absolute value and serum total LD activity usually showed statistically significant differences (P less than 0.05) among patients with active CGL, those in partial remission, and those in complete remission, but did not distinguish between subgroups of individuals with active CGL. Elevation of the serum LD-5/total LD ratio in 16 of 58 patients was due to hepatic injury or methodologic imprecision, showing analytically insignificant, borderline abnormalities in all cases of active CGL. In 10 of 62 patients in complete remission or partial remission, however, such elevation was unexplained. Our results indicate that the evaluation of serum LD-3 values in both absolute and relative terms slightly increases the clinical sensitivity of LD-3, and, therefore, suggest that LD-3 might be a useful marker for CGL.

Biomarkers, Tumor↗
PubMed1991

Immunomodulation of the induction phase of lymphokine-activated killer activity by acute phase proteins.

Effective treatment of head and neck cancer with biologic response modifiers may be benefitted by an understanding of in vivo factors capable of modulating the lymphokine-activated killer (LAK) cell phenomenon. Eighteen patients with squamous cell carcinoma of the head and neck were studied. Killer cells from each patient, activated by recombinant interleukin-2 (10 U/ml), were induced in either complete medium alone or complete medium plus 10% autologous serum solution and analyzed. Cytotoxicity against both K562 and squamous cell carcinoma (MDA686-Ln) cell lines was determined by use of standard chromium-release assays. The immunomodulatory capacity of serum was correlated with levels of various acute phase proteins. Autologous serum significantly inhibited the induction phase of the LAK phenomenon in 61% of patients and stimulated it in 22%. No patients with early stage I or II disease had significant inhibition of induction. No direct correlation between inhibition and serum acute phase protein levels were seen. An inverse relationship was seen between the C3 component of complement and induction inhibition (r = -0.6). These findings suggest that advances of in vivo immunomodulatory therapy will require elucidation of mechanisms of serologic inhibition of the induction phase of the LAK phenomenon. Such studies may lead to serologic modification to enhance treatment efficacy of biologic response modifiers.

Acute-Phase Proteins↗
PubMed1990

Significance of C1q-binding macromolecules within the head and neck cancer patient.

Elevated levels of macromolecules, within the peripheral blood of head and neck cancer patients, capable of binding the first component of complement (C1qBM) in vitro have prognostic implication. Namely, elevated levels of C1qBM have been associated with nonresponse to induction chemotherapy. In this investigation, a series of in vitro studies regarding the biological properties of C1qBM were combined with a longitudinal analysis of 112 previously untreated head and neck cancer patients. Our purpose was to shed light on the biological significance of this circulating macromolecule, a substance composed, in part, of IgG and IgM. A potential confounding influence of C1qBM with induction chemotherapy, which could contribute to observed prognostic findings, was negated by two in vitro observations: the macromolecule failed both to bind the chemotherapeutic agents cisplatin, bleomycin, and 5-fluorouracil and to impede the cytotoxic effect of these same drugs on a cultured human head and neck cancer cell line. The clinical relevance of C1qBM was reinforced by the observation that elevated levels predicted a high probability of death with disease (P = 0.005 by Cox's proportional hazards model). The prognostic implication was independent of the use of induction chemotherapy, i.e., patients with high C1qBM levels treated with multimodality therapy not composed of anticancer drugs did equally poorly. Thus, the prognostic significance of C1qBM in patients undergoing induction chemotherapy appears independent of drug effect and appears reflective of tumors that are more rapidly progressive and potentially less responsive to therapeutic intervention, including combinations of surgery, radiation, and/or chemotherapy.

Antigen-Antibody Complex↗