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Biomedical subjects

K Liu

Publications and source records attributed to K Liu.

At least 325 records · Page 18Linked to original sources
PubMed1996

Body mass index in young adults: Associations with parental body size and education in the CARDIA Study.

OBJECTIVES: Associations of parental education, parental body size, and offspring's education with body mass index and 7-year change in body mass index were examined among participants in the Coronary Artery Risk Development in Young Adults (CARDIA) study. METHODS: CARDIA is a study of coronary artery disease risk factors in 5115 Black and White persons aged 18 to 30 at baseline. Analyses of covariance were carried out with body mass index and change in body mass index as the dependent variables, and with parental education, parental body size, and participant education as the major independent variables. RESULTS: Father's body size was positively associated with participant's baseline body mass index among Black men, White men, and White women. Mother's body size was positively associated with baseline body mass index among all race-sex groups, and with change in body mass index among White women. Father's education was inversely associated with baseline body mass index among Black men and White women, and with change among White women. CONCLUSIONS: Parental education may influence body mass index and changes in young adulthood, especially among White women. Such associations may be both genetic and environmental and may be important for obesity prevention efforts.

Adolescent↗
PubMed1996

Exposure to ultraviolet B radiation increases the tolerance of mouse skin to daily X irradiation.

Based on the hypothesis that acceleration of repopulation in skin during fractionated irradiation is triggered by an inflammatory response of the dermis to radiation-induced epidermal hypoplasia, we produced a mild erythema by exposure to UVB radiation before applying different X-irradiation schedules. At different times ranging from 6 h to 14 days after a single exposure to UVB radiation which caused a distinct erythema, a 2-cm skin field on the legs of mice was irradiated with either different single doses or five daily fractions of 3 Gy followed by different single top-up doses of 300 kV X rays. Skin reactions were scored daily for 4 weeks and the occurrence of moist desquamation was taken to construct dose-response curves and to calculate ED50 values. Five days after exposure to UVB radiation and later, radioresistance of epidermis to single and fractionated X irradiation was significantly increased. Results were analyzed using the linear-quadratic formalism to identify possible mechanisms for this UV-radiation-induced radioresistance. The data suggest that exposure to UVB radiation led to a gradual increase in the number of epidermal stem cells and their repopulation rate.

Animals↗
PubMed1996

Medium-term effects of betaxolol monotherapy and combination therapy with nitrendipine on lipoprotein and apolipoprotein metabolism in patients with mild to moderate essential hypertension.

The objective of this study was to assess the medium-term effects of betaxolol, a long-acting, lipid-soluble, cardioselective, beta-adrenergic antagonist, alone and in combination with nitrendipine on blood pressure (BP) and metabolism of lipid, lipoprotein and apolipoprotein in patients with mild to moderate hypertension. Forty-seven patients (21 men, 26 women, average age 54 years) participated in an open controlled clinical trial. After a 4-week washout period, all of the patients received betaxolol monotherapy at a dose of 5-10 mg daily for 6 months (Phase I). From month 7 through month 12 (Phase II), half of the total patients (Group B, n = 23) with diastolic blood pressure (DBP) of 95 mm Hg or more at the end of Phase I were also given nitrendipine (10-20 mg, once daily), while the remaining patients (Group A, n = 24) continued to receive only betaxolol. Systolic blood pressure (SBP), DBP, and heart rate (HR) were monitored once monthly. Serum lipid profiles were measured at study entry and after 6 and 12 months of therapy. Betaxolol significantly reduced SBP, DBP, and HR in both groups during Phase I, and the reductions in SBP and DBP were markedly less in Group B than in Group A. During Phase II, the additional reduction of SBP and DBP to levels similar to those in Group A was achieved by betaxolol in combination with nitrendipine, and HR was slightly but significantly increased. Betaxolol monotherapy reduced serum levels of high density lipoprotein cholesterol (HDL-C) and increased levels of triglyceride, apolipoprotein (apo) C-II and apo C-III. Combination therapy with betaxolol and nitrendipine increased serum apo A-I but did not affect other lipid profiles. Our results indicate that betaxolol is an effective antihypertensive drug which has a preferable effect on HR and HDL profiles when combined with nitrendipine.

Adrenergic beta-Antagonists↗
PubMed1996

[Application of radiolabeled anti-HBx monoclonal antibody for HCC targeting therapy].

OBJECTIVE: To explore the possibility of anti-HBx McAb as a carrier of HCC targeting therapy after we prepared successfully the anti-HBx monoclonal antibody by immunizing BALB/C mice with 17KD hepatitis B virus X protein. METHODS: The antibody was prepared, purified, identified, radiolabled and used in nude mice bearing human HCC and two HCC patients respectively for experimental and clinical trials. In the experimental study, 0.5mCi 131I-anti-HBx was injected peritoneally. In the clinical trial, the patients were treated with 131I-anti-HBx by injecting into the hepatic artery. After the treatment for one course, a total dose of 37.5 mCi was administered. RESULTS: The survival periods of the mice were prolonged and the tumors were suppressed significantly. The symptoms of the patients were improved significantly with decreased titre of AFP. The B-ultrasonic and CT scanning showed that the tumors became smaller. For these reasons, one of the two patients was reoperated. The tumor was removed and necrosis of the whole tumor was noted except few living tumor cells on the edge of tumor specimen. CONCLUSIONS: It is possible to use the anti-HBx monoclonal antibody as a carrier for human HCC targeting therapy.

Adult↗
PubMed1996

Regulation of tissue-type plasminogen activator and plasminogen activator inhibitor type-1 in cultured rat Sertoli and Leydig cells.

New data are provided to show that (i) rat Sertoli cells produce two types of plasminogen activators, tissue type (tPA) and urokinase type (uPA), and a plasminogen activator inhibitor type-1 (PAI-1); (ii) both tPA (but not uPA) and PAI-1 secretion in the culture are modified by FSH, forskolin, dbcAMP, GnRH, PMA and growth factors (EGF and FGF), but not by hCG and androstenedione (delta 4); (iii) in vitro secretion of tPA and PA-PAI-1 complexes of Sertoli cells are greatly enhanced by presence of Leydig cells which produce negligible tPA but measurable PAI-1 activity; (iv) combination culture of Sertoli and Leydig cells remarkably increases FSH-induced PAI-1 activity and decreases hCG- and forskolin-induced inhibitor activity as compared with that of two cell types cultured alone. These data suggest that rat Sertoli cells, similar to ovarian granulosa cells, are capable of secreting both tPA and uPA, as well as PAI-1. The interaction of Sertoli cells and Leydig cells is essential for the cells to response to hormone stimulation for tPA and PAI-1 secretion.

Animals↗
PubMed1996

Dietary beta-carotene, vitamin C, and risk of prostate cancer: results from the Western Electric Study.

Dietary factors are likely candidates for important determinants of prostatic cancer risk. Among the most investigated nutritional factors have been antioxidants. We evaluated dietary beta-carotene and vitamin C in relation to subsequent risk of prostate cancer in a prospective study of 1,899 middle-aged men. We combined prostate cancer cases diagnosed in the first 24 years of follow-up with incident cases identified from the Health Care Financing Administration hospitalization and outpatient files during an additional 6-year follow-up period. We obtained death certificates for all decedents. During the 30-year follow-up, prostate cancer developed in 132 men. There was no indication that consumption of beta-carotene or vitamin C was related to increased or decreased risk of prostate cancer. Relative risks for highest vs lowest quartiles of beta-carotene and vitamin C intake were 1.27 [95% confidence interval (CI) = 0.75-2.14] and 1.03 (95% CI = 0.59-1.60), respectively, after adjustment for age, number of cigarettes smoked per day, dietary cholesterol and saturated fat, alcohol consumption, total energy intake, and occupation. Associations between intake of these nutrients and risk of prostate cancer differed depending on whether the cancer was diagnosed during the first 19 years of follow-up or the next 11 years of follow-up. Overall survival over the 30 years of follow-up was positively associated with intake of beta-carotene and vitamin C.

Adult↗
PubMed1996

Comparisons of blood pressure between Asian-American children and children from other racial groups in Chicago.

RESEARCHERS COMPARED AVERAGE BLOOD PRESSURE, prevalence of elevated blood pressure, and average anthropometric measurements of Asian children with those same measures in children from other racial and ethnic groups, including blacks, whites, and Hispanics. The sample consisted of 1318 boys and 1548 girls ages 6 to 9 who had complete blood pressure and anthropometric data, which were derived from a health screening program in nonpublic schools conducted by the Chicago Department of Health from 1975 to 1978. The systolic pressure, adjusted for age, weight, and height, for Asian, black, Hispanic, and white boys was 108.1, 105.8, 104.7, and 105.6 mmHg, and for diastolic pressure, the adjusted values were 59.6, 58.9, 56.3, and 57.4 mmHg. For both systolic and diastolic, the differences between Asian boys and white boys and between Asian boys and Hispanic boys were statistically significant. For girls, the results were similar. In addition, for boys, the prevalence rates of elevated blood pressure (systolic greater than or equal to 122 mmHg or diastolic greater than or equal to 78 mmHg) were similar among the four groups. For girls, the prevalence rate for Asians was higher than those in the other groups; however, the differences were not statistically significant. Since hypertension is a major health problem in Asians, it is important to confirm these findings and to understand why mean blood pressure adjusted for age and body size is higher in Asian children than in other racial groups.

Asian↗
PubMed1996

Complete resolution of diastolic mitral regurgitation in chronic, but not acute aortic regurgitation after aortic valve replacement--a transesophageal echocardiography study.

A 65-year-old male was admitted with progressive dyspnea on exertion. Severe aortic regurgitation (AR) had been disclosed by transthoracic echocardiography 10 mon previously. Aortic valve replacement was proposed and intraoperative transesophageal echocardiography on color Doppler imaging revealed severe aortic regurgitation, moderate global hypokinesis of the left ventricle and mild-to-moderate diastolic mitral regurgitation. The regurgitant jet was seen to pass through the posterior mitral leaflet in a direction toward the center of left atrium. Mitral valve perforation was suspected. But mitral valve was found to be intact after a thorough exploration. Surgery proceeded uneventfully and diastolic mitral regurgitation was resolved completely after the aortic valve was successfully replaced. Diastolic mitral regurgitation has been reported to be closely related to acute AR, but the picture differs somewhat from the present example. The possible cause for this disease presentation is to be further investigated.

Aged↗
PubMed1996

Retrograde ascending aortic dissection diagnosed by intraoperative transesophageal echocardiography.

Aortic dissection is a risky but challenging cardiovascular emergency and rapid surgical intervention for life-saving is sometimes inevitable. For detection of aortic dissection, computed tomography, magnetic resonance imaging, aortography all have their advantages but all have their limitations. Transesophageal echocardiography (TEE), which is portable and relatively noninvasive, is a highly sensitive and specific diagnostic tool for evaluation of aortic diseases. We presented a case in which preoperative imaging studies such as MRI and cardiac catheterization were all suggestive of DeBakey's type I aortic dissection. However, it was further proved to be a retrograde ascending aortic dissection during intraoperative TEE imaging study as a retrograde ascending blood flow was demonstrated within the dissected aortic lumen. So the initial operative scheme was changed and sternothoracoabdominal incision was selected for better exposure for one-stage repair of the entire thoracic aorta. Nevertheless, severe intrathoracic adhesion and case to bleed prevented any aggressive intervention to proceed. The operation was called off and the patient was transferred to ICU for further medical treatment.

Aged↗
PubMed1996

Detection of cerebral desaturation during cardiopulmonary bypass by cerebral oximetry.

BACKGROUND: As oxygen consumption increases acutely during rewarming period in extracorporeal cardiopulmonary bypass (CPB), it is crucial to maintain cerebral oxygen delivery at this critical moment. The aim of this study was to evaluate the effectiveness of a cerebral oximeter (INVOS 3100, Somanetics Corporation, Troy, MI, USA) in monitoring cerebral oxygen balance during rewarming in CPB by correlating optical spectroscopic determinations with jugular bulb oxyhemoglobin saturation measurements. METHODS: On trial were 15 patients who underwent cardiac surgery under moderate hypothermic nonpulsatile CPB. Infrared spectroscopic soma sensor was placed over the patient's left frontal area to continuously monitor the regional cerebral oxygen saturation (SrO2) and the ipsilateral internal jugular vein was cannulated for measurement of venous oxyhemoglobin saturation (SjO2) at the jugular bulb. The changes of SjO2, SrO2, mean arterial pressure (MAP) and nasopharyngeal temperature (NPT) were recorded 5 min before CPB, instantaneously at initiation of CPB and at the point where every increment of 1 degree C in NPT was reached during CPB rewarming. The data obtained were statistically analyzed for any correlation between two methods using repeated measurements of ANOVA and linear regression. RESULTS: There was no correlation between SjO2 and SrO2, between MAP change and SjO2 or SrO2 at the start of CPB, but a significant reduction of SjO2 during rewarming period was observed which was inversely correlative with NPT changes (r(2) = 0.64, p < 0.05). However, SrO2 did not show a similarity. CONCLUSIONS: Jugular bulb desaturation which correlated inversely with rewarming speed as disclosed in this study indicated that the temperature change during rewarming was crucial for cerebral oxygen balance. Being less sensitive and still more unspecific, the INVOS 3100 cerebral oximeter is incapable and not recommended for monitoring cerebral oxygen saturation in CPB.

Aged↗
PubMed1996

[Highly metastatic model of human hepatocellular carcinoma established in nude mice using orthotopic organ selection of metastatic variant from patient specimens].

We succeeded in establishing a highly metastatic model of human hepatocellular carcinoma (HCC) in athymic nude mice (LCI-D20). The metastatic variant was obtained by using orthotopic implantation of histologically intact tumor tissue selected from 30 fresh surgical specimens. It exhibited various features seen in clinical liver cancer patients: local growth, regional invasion, spontaneous intrahepatic, lymphnode and pulmonary metastases, and peritoneal seeding with bloody ascites. All mice with the implant-tumor died within 6 weeks due to serious metastasis. The 100% rate of transplantability and metastasis maintained for over 16 passages. The morphological characteristics of implant tumor cells were similar to those of the original specimen by histological and electronmicroscopic observation, and kept on secreting alpha-fetoprotein (AFP) in recipient animals. Those data from DNA content analysis by flow cytometry (D. I. value, 1.61) and chromosome karyotype revealed the existence of hypotriploid and hypertriploid cells. The results demonstrated that orthotopic implantation model of human HCC displayed features of human clinical HCC in animals. It should allow development of new treatment modalities and study of metastatic mechanism of human HCC.

Animals↗
PubMed1996

[Analysis of cell origin of human hepatocellular carcinoma according to p53 gene mutation].

Paraffin-embedded hepatocellular carcinoma (HCC) samples were used to study point mutation of p53 gene at 249 codon in the exon 7 by polymerase chain reaction and gel electrophoresis under Hae III enzyme digestion. Fourteen primary tumor foci and 15 recurrent tumor foci from 11 patients were investigated. p53 gene point mutation was detected in 10 of 14 primary foci (71.4%), in 10 of 15 recurrent foci (66.7%) and in 10 of 12 multiple foci. The p53 genotype of the primary and recurrent tumor foci was the same in 5 patients but different in 6. The p53 genotype of the primary and recurrent tumor foci was identical in 5 patients with multiple tumor nodules. The results suggest that recurrent HCC was multi-centric in origin in 7 of the 11 patients but was mono-centric in the other 4 patients studied.

Adult↗
PubMed1996

[Studies on distribution patterns of modulator CGRP in different motoneuron pools in rats].

Using retrograde labelling combined with calcitonin gene-related peptide (CGRP) immunocytochemistry technique, distribution patterns of the content of calcitonin gene-related peptide-like immunoreactivity (CGRP-LI) were studied in two different motoneuron (Mn) pools supplying soleus (SOL, slow-twitch muscle) and extensor digitorium longus (EDL, fast-twitch muscle) of hindlimbs in rats during development. The Mn pools were identified with a novel retrograde tracer, choleragen B subunit (CB) coupled with colloidal gold (CB-Au, 5 nm particle, prepared by ourselves), which was injected into EDL or SOL. After the silver intensification for visualizing colloidal gold particles, CGRP immunocytochemistry were processed. The CB-Au retrogradely identified Mns in each Mn pool were counted and CGRP-LI intensity of Mns was evaluated as strong, moderate, weak and negative. The double labelling revealed different distribution patterns of CGRP-LI content between SOL and EDL Mn pools during development. Comparing the level of CGRP expression between the two Mn pools, SOL Mn pool had a higher ratio of neurons lacking CGRP-LI/weak CGRP LI and a lower proportion of strongly CGRP-LI labelled ones. These results suggest that the difference in content of CGRP-LI in Mns is related to the type of muscular motor activity.

Animals↗
PubMed1996

[The relationship between prognosis of esophageal squamous carcinoma and Langerhans cell].

The operative tumor specimen of esophageal squamous carcinoma were studied with immunohistochemical (ABC) method S-100 protein staining. Under the light microscopy, we observed the morphology, number and distribution of Langerhan's cells (LC) in different portion of the tumor mass and its relationship with the pathological staging in 167 cases. We observed also the relationship between LC and the postoperative survival period in 127 cases followed for more than 3 years. These results suggested found that positive relation between the number of LC in the cancer nest and in the lymphfollicle with the increasing of TNM classification. The number of LC in the cancer nest significantly increased in state III and IV cases than II cases. On the contrary, the number of LC in the peritumor and interstitial tissue decreased while the TNM classification was increasing. These findings suggested that the survival period was shorter in patients whose LC had increased in the cancer nest, whereas the survival period would be longer in those patients whose LC had increased in the tissue around the tumor mass, in the mucosa near the tumor as well as in the interstitial tissue. These two points might be used as an immunological para-meter for the assessment of the prognosis.

Adult↗
PubMed1995

Ovulation efficiency is reduced in mice that lack plasminogen activator gene function: functional redundancy among physiological plasminogen activators.

Several lines of indirect evidence suggest that plasminogen activation plays a crucial role in degradation of the follicular wall during ovulation. However, single-deficient mice lacking tissue-type plasminogen activator (tPA), urokinase-type plasminogen activator (uPA), or PA inhibitor type 1(PAI-1) gene function were recently found to have normal reproduction, although mice with a combined deficiency of tPA and uPA were significantly less fertile. To investigate whether the reduced fertility of mice lacking PA gene function is due to a reduced ovulation mechanism, we have determined the ovulation efficiency in 25-day-old mice during gonadotropin-induced ovulation. Our results reveal that ovulation efficiency is normal in mice with a single deficiency of tPA or uPA but reduced by 26% in mice lacking both physiological PAs. This result suggests that plasminogen activation plays a role in ovulatory response, although neither tPA nor uPA individually or in combination is obligatory for ovulation. The loss of an individual PA seems to be functionally complemented by the remaining PA but this compensation does not appear to involve any compensatory up-regulation. Our data imply that a functionally redundant mechanism for plasmin formation operates during gonadotropin-induced ovulation and that PAs together with other proteases generate the proteolytic activity required for follicular wall degradation.

Animals↗