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Biomedical subjects

K Liu

Publications and source records attributed to K Liu.

At least 181 records · Page 10Linked to original sources
PubMed1999

Ten-year incidence of elevated blood pressure and its predictors: the CARDIA study. Coronary Artery Risk Development in (Young) Adults.

Few prospective studies have examined associations of lifestyle factors or variables in the insulin resistance syndrome (syndrome X) with incidence of elevated blood pressure (BP) in black subjects and women. This report estimates the 10-year incidence of high blood pressure (HBP) and high normal blood pressure (HNBP) in the biracial cohort of the Coronary Artery Risk Development in (Young) Adults Study (CARDIA), and examines lifestyle factors and four syndrome X variables, measured at baseline, as predictors. CARDIA examined 5115 black and white men and women aged 18-30 years in 1985-1986, and re-examined them at 2, 5, 7, and 10 years. The 10-year incidence of HBP was 16.4% in black men, 7.8% in white men, 13.1% in black women, and 3.2% in white women, while the 10-year incidence of HBP or HNBP was 29.5%, 16.2%, 19.2%, and 6.3%, respectively, in the four sex-race subgroups. Predictors included body mass index, waist circumference, physical activity, alcohol intake, pulse rate, cigarette smoking, education, fasting insulin, triglycerides, uric acid, and high-density lipoprotein cholesterol, as well as age and systolic BP. In univariate analyses, each of these variables was significantly related to incidence in at least one of the four sex-race groups. In multivariate analyses that included control for age and systolic pressure, independent predictors included fasting insulin in white men and women, triglycerides in white men, uric acid and pulse rate in black men, waist circumference in white men and black women, and education (inverse) in white men and black and white women. These results suggest that lower socioeconomic status, as assessed by education level, and one or more syndrome X variables, ie, fasting insulin, triglycerides, uric acid, may be associated with development of elevated BP in young adults.

Adult↗
PubMed1999

Patient-controlled epidural analgesia with morphine or morphine plus ketamine for post-operative pain relief.

Sixty patients were randomly assigned to two equal groups. Group I received epidural morphine 1 mg after surgery and used a patient-controlled analgesia device programmed to deliver morphine 0. 2 mg h-1, 0.2 mg per bolus. Group II received an epidural loading dose of morphine 1 mg plus ketamine 5 mg and used a patient-controlled analgesia device programmed to deliver morphine 0. 2 mg+ketamine 0.5 mg h-1, morphine 0.2 mg+ketamine 0.5 mg per bolus with a lockout time of 10 min. The mean morphine consumption was 8. 6+/-0.7 mg for group I and 6.2+/-0.2 mg for group II. Although group II utilized significantly less morphine (P < 0.05), pain relief was significantly better in group II than in group I (P < 0.05) in the first 3 h. Vomiting occurred more frequently in group I (26%) than in group II (13%). The frequency and severity of pruritus and level of sedation were similar in the two groups. These findings suggest that patient-controlled epidural analgesia with morphine plus ketamine may provide effective analgesia with a lesser dose of morphine and fewer subsequent side effects, compared with patient-controlled epidural analgesia with morphine alone after lower abdominal surgery.

Abdomen↗
PubMed1999

Expression of tissue type and urokinase type plasminogen activators as well as plasminogen activator inhibitor type-1 and type-2 in human and rhesus monkey placenta.

The distribution of mRNAs and antigens of tissue type (t) and urokinase type (u) plasminogen activators (PA) plus their corresponding inhibitors, type-1 (PAI-1) and type-2 (PAI-2) were studied in human and rhesus monkey placentae by in situ hybridisation and immunocytochemistry. Specific monkey cRNA and antibodies against human tPA, uPA, PAI-1 and PAI-2 were used as probes. The following results were obtained. (1) All the molecules tPA, uPA, PAI-1 and PAI-2 and their mRNAs were identified in the majority of the extravillous cytotrophoblast cells of the decidual layer between Rohr's and Nitabuch's striae and in cytotrophoblast cells of the chorionic plate, basal plate, intercotyledonary septae and cytotrophoblast cells of the chorionic villous tree. (2) Expression of uPA and PAI-2 was noted in villous trophoblast whereas tPA and PAI-1 were mainly concentrated where detachment from maternal tissue occurs. (3) No expression of tPA, uPA, PAI-1 and PAI-2 was observed in the basal plate endometrial stromal cells, chorionic plate connective tissue cells, septal endometrial stromal cells or villous core mesenchyme. (4) The distribution of probes observed following in situ hybridisation is generally consistent with the immunofluorescence pattern of the corresponding antigens and no significant interspecies differences were noted. It is possible that both decidual and extravillous trophoblast cells of placentae of human and rhesus monkey are capable of producing tPA, uPA, PAI-1 and PAI-2 to differing extents. Coordinated expression of these genes in the tissue may play an essential role in the maintenance of normal placentation and parturition. The differences in distribution we observed are consistent with the suggestion that coordinated expression of tPA and its inhibitor PAI-1 may play a key role in fibrinolytic activity in the early stages of placentation and separation of placenta from maternal tissue at term. On the other hand, uPA with its inhibitor PAI-2 appears mainly to play a role in degradation of trophoblast cell-associated extracellular matrix, and thus may be of greatest importance during early stages of placentation.

Animals↗
PubMed1999

Leg symptoms, the ankle-brachial index, and walking ability in patients with peripheral arterial disease.

OBJECTIVE: To determine how functional status and walking ability are related to both severity of lower extremity peripheral arterial disease (PAD) and PAD-related leg symptoms. DESIGN: Cross-sectional study. SETTING: Academic medical center. PARTICIPANTS: Patients aged 55 years and older diagnosed with PAD in a blood flow laboratory or general medicine practice (n = 147). Randomly selected control patients without PAD were identified in a general medicine practice (n = 67). MEASUREMENTS: Severity of PAD was measured with the ankle-brachial index (ABI). All patients were categorized according to whether they had (1) no exertional leg symptoms; (2) classic intermittent claudication; (3) exertional leg symptoms that also begin at rest (pain at rest), or (4) exertional leg symptoms other than intermittent claudication or pain at rest (atypical exertional leg symptoms). Participants completed the 36-Item Short-Form Health Survey (SF-36) and the Walking Impairment Questionnaire (WIQ). The WIQ quantifies patient-reported walking speed, walking distance, and stair-climbing ability, respectively, on a scale of 0 to 100 (100 = best). MAIN RESULTS: In multivariate analyses patients with atypical exertional leg symptoms, intermittent claudication, and pain at rest, respectively, had progressively poorer scores for walking distance, walking speed, and stair climbing. The ABI was measurably and independently associated with walking distance (regression coefficient = 2.87/0.1 ABI unit, p =.002) and walking speed (regression coefficient = 2.09/0.1 ABI unit, p =.015) scores. Among PAD patients only, pain at rest was associated independently with all WIQ scores and six SF-36 domains, while ABI was an independent predictor of WIQ distance score. CONCLUSIONS: Both PAD-related leg symptoms and ABI predict patient-perceived walking ability in PAD.

Aged↗
PubMed1999

Food and nutrient exposures: what to consider when evaluating epidemiologic evidence.

Nutritional epidemiology is the science concerned with conducting research into the relation between diet and disease risk. The public has a great deal of interest in this issue. Much of that interest, however, is fueled by the publication of sensationalized, startling, and often contradictory health messages. Unfortunately, there is a great deal of confusion in both the scientific press and the public or lay press about the nature of nutritional epidemiology, its strengths, and its limitations. The purpose of this article is to discuss these strengths and limitations. It is hoped that clarification of these issues can help lead to a resolution of the research community's and lay public's misunderstandings about nutritional epidemiology research.

Causality↗
PubMed1999

Diagnostic accuracy in fine-needle aspiration of soft tissue and bone lesions. Influence of clinical history and experience.

Interpretation of soft tissue and bone lesions with fine-needle aspiration (FNA) is difficult. We determined whether clinical history or experience improves diagnostic accuracy of FNA interpretation of these lesions. Four cytopathologists with varying degrees of experience retrospectively reviewed 89 soft tissue and bone lesions, initially without knowledge of clinical history and subsequently with knowledge of clinical history. Each time, the pathologist rendered a precise diagnosis (histogenetic classification, e.g., angiosarcoma, lipoma) for each case and classified the lesion into one of 4 categories: benign, probably benign, probably malignant, or malignant. The proportion of correct precise diagnoses was calculated. Also, the numbers of correct and incorrect classifications of malignancy were used in standard relative operating characteristic (ROC) curve analysis. The area under the ROC curve was estimated to give an indicator of diagnostic accuracy. Knowledge of clinical history increased the proportion of correct diagnoses and the accuracy of the classification for all observers. Experienced observers more accurately classified lesions, and knowledge of clinical history particularly improved the diagnostic accuracy of less experienced observers.

Biopsy, Needle↗
PubMed1999

Risk factors for falls in hospitalized older medical patients.

BACKGROUND: The incidence of falls among older hospitalized patients is higher than that of community-dwelling older persons. Prevention is important, but factors associated with these falls are less well studied than falls occurring in the community or nursing homes. METHODS: This study was conducted in an acute-care general hospital in Hong Kong. During November 1995 to March 1997, all older inpatients who fell during hospitalization were assessed by a geriatrician, a physiotherapist, and an occupational therapist. A standardized protocol to study the clinical and performance-oriented functional factors was employed. A sex- and age-matched hospital control was recruited for each case. In total, 51 cases and controls (mean ages 77.8 +/- 7.3 years and 77.5 +/- 7.0 years, respectively) were studied. RESULTS: Among the multiple clinical and functional risk factors for falls identified, lower limb weakness (i.e., power less than MRC grade 4 in one or both lower limbs) and poor tandem walk ability emerged as two significant predictive factors for falls in the hospital. The overall classification accuracy of fallers and nonfallers was 79%. The sensitivity was 84% and specificity was 75%. Clinical factors were the underlying causes for the lower limb weakness and poor tandem walk performance. CONCLUSIONS: Among clinical and functional risk factors for falls in the older medical patient, lower limb weakness and poor tandem walk ability were most predictive. Falls prevention programs in hospitals should employ these two tests as screening instruments.

Accidental Falls↗
PubMed1999

Dexamethasone decreases epidural morphine-related nausea and vomiting.

UNLABELLED: The aim of our study was to compare the antiemetic effect of IV dexamethasone with saline control in preventing epidural morphine-related nausea and vomiting. Eighty patients requiring epidural anesthesia for abdominal total hysterectomy were enrolled in a randomized, double-blinded, and placebo-controlled study. At the end of surgery, all patients received epidural morphine 3 mg for relief of postoperative pain. Before the morphine injection, the dexamethasone group (n = 40) received IV dexamethasone 8 mg, whereas the saline group (n = 40) received IV saline. We found that the incidence of postoperative vomiting was 5% in the dexamethasone group and 25% in the saline group (P<0.05). The total incidence of nausea and vomiting was 16% in the dexamethasone group and 56% in the saline group (P<0.001). IV dexamethasone 8 mg significantly decreases the incidence of epidural morphine-related nausea and vomiting. IMPLICATIONS: We evaluated IV dexamethasone versus saline control in preventing epidural morphine-related nausea and vomiting in patients receiving epidural morphine for postoperative pain control. We found that IV dexamethasone significantly decreased the total incidence of nausea and vomiting after epidural morphine. IV dexamethasone may be a valuable treatment for preventing epidural morphine-related nausea and vomiting.

Adult↗
PubMed1999

The preoperative administration of intravenous dextromethorphan reduces postoperative morphine consumption.

UNLABELLED: We evaluated the effect of dextromethorphan on postoperative pain management. Sixty ASA physical status I-III female patients undergoing major abdominal surgery underwent standardized general anesthesia. Thirty patients received an i.v. infusion of dextromethorphan 5 mg/kg before anesthetic induction (Pre group), whereas the remaining 30 patients received the same volume of isotonic sodium chloride solution, followed by a postoperative i.v. infusion of dextromethorphan 5 mg/kg (Post group). Patients in the Pre group received the same volume of isotonic sodium chloride solution postoperatively. All patients were then treated with patient-controlled i.v. analgesia, which administered a 0.6-mg bolus of morphine on demand (maximal 4 h dose 20 mg). The mean visual analog pain score during cough or movement and at rest were similar in the two groups in the first 3 days postoperatively. However, Post group patients consumed more morphine than Pre group patients during the first 2 days (P < 0.01). The sedation scores, patient satisfaction, and the incidence of morphine-related side effects were similar between the two groups. We conclude that the preoperative administration of dextromethorphan 5 mg/kg reduces postoperative morphine consumption compared with postoperative administration. IMPLICATIONS: In this double-blinded study, we found that the preoperative administration of i.v. dextromethorphan 5 mg/kg, compared with postoperative administration, reduces postoperative morphine consumption, which may provide clinical evidence of preemptive or preventive analgesic effects of dextromethorphan.

Adult↗
PubMed1999

Reversible tumorigenesis induced by deficiency of vasodilator-stimulated phosphoprotein.

Random homozygous knockout (RHKO) is an antisense RNA strategy capable of identifying genes whose homozygous functional inactivation yields a selectable phenotype in cells growing in culture. Using this approach, we isolated NIH 3T3 fibroblast clones that showed the ability to form colonies on 0.5% agar and tumors in nude mice. The gene inactivated in one of these clones was found to encode VASP (vasodilator-stimulated phosphoprotein), a previously identified protein that binds to components of the cadherin-catenin junctional complex and has been implicated in cell-cell interactions, the formation of actin filaments, and the transmission of signals at the cytoskeleton-membrane interface. Fibroblasts made deficient in VASP by RHKO showed loss of contact inhibition, and consequently, continued cell division past confluence. Restoration of VASP function by reversal of RHKO yielded cells that had lost the neoplastic capabilities acquired during RHKO. Overproduction of VASP mRNA in the sense or antisense orientation from expression constructs introduced by transfection into naive NIH 3T3 fibroblasts also resulted in neoplastic transformation, implying that normal cell growth may require the maintenance of VASP expression within a narrow range. Our results implicate VASP in tumorigenesis and/or cancer progression.

3T3 Cells↗
PubMed1999

Efficient nuclear delivery of antisense oligodeoxynucleotides and selective inhibition of CETP expression by apo E peptide in a human CETP-stably transfected CHO cell line.

N,N-Dipalmitylglycyl-apolipoprotein E (129-169) peptide (dpGapoE) is an efficient gene delivery system for both plasmids and antisense oligodeoxynucleotides (ODNs). To develop a new and efficient approach to the regulation of cholesteryl ester transfer protein (CETP) expression, we used dpGapoE to transfect phosphorothioate antisense ODNs against nucleotides 329 to 349 of human CETP cDNA into a human CETP-stably transfected Chinese hamster ovary (CHO) cell line (hCETP-CHO). After transfection, translocation to the nuclei and concentration in nuclear structures were observed in >95% of the cells at 6 and 12 hours by fluorescence microscopy. No membrane disruption was observed after transfection of ODNs by dpGapoE. Although the translocation stability of phosphorothioate ODNs in the nuclei continued for >48 hours, it had weakened after 24 hours. Cellular CETP mRNA levels gradually declined, and the maximum reduction in the mRNA level (>50%) was observed at 36 hours, after which the mRNA level started to recover. CETP activity in the culture medium declined over 72 hours. The maximum reduction in CETP activity was observed at 36 hours (53.8% of control). Neither CETP mRNA nor CETP activities changed throughout the experiment after the transfection of sense phosphorothioate ODNs delivered by dpGapoE complex or naked antisense ODNs. We conclude that (1) the novel synthetic dpGapoE was a highly effective and nontoxic vehicle for the nuclear delivery of antisense ODNs into hCETP-CHO cells and (2) antisense ODNs selectively inhibited both CETP expression and activity in an hCETP-CHO cell line. This approach may enable gene regulation in vivo and could possibly be used as an antiatherosclerotic agent to alter high density lipoprotein metabolism.

Animals↗
PubMed1999

Heart rate and subsequent blood pressure in young adults: the CARDIA study.

The objective of the present study was to examine the hypothesis that baseline heart rate (HR) predicts subsequent blood pressure (BP) independently of baseline BP. In the multicenter longitudinal Coronary Artery Risk Development in Young Adults study of black and white men and women initially aged 18 to 30 years, we studied 4762 participants who were not current users of antihypertensive drugs and had no history of heart problems at the baseline examination (1985-1986). In each race-sex subgroup, we estimated the effect of baseline HR on BP 2, 5, 7, and 10 years later by use of repeated measures regression analysis, adjusting for baseline BP, age, education, body fatness, physical fitness, fasting insulin, parental hypertension, cigarette smoking, alcohol consumption, oral contraceptive use, and change of body mass index from baseline. The association between baseline HR and subsequent systolic BP (SBP) was explained by multivariable adjustment. However, HR was an independent predictor of subsequent diastolic BP (DBP) regardless of initial BP and other confounders in white men, white women, and black men (0.7 mm Hg increase per 10 bpm). We incorporated the part of the association that was already present at baseline by not adjusting for baseline DBP: the mean increase in subsequent DBP was 1.3 mm Hg per 10 bpm in white men, white women, and black men. A high HR may be considered a risk factor for subsequent high DBP in young persons.

Adolescent↗
PubMed1999

Distinct expression of gelatinase A [matrix metalloproteinase (MMP)-2], collagenase-3 (MMP-13), membrane type MMP 1 (MMP-14), and tissue inhibitor of MMPs type 1 mediated by physiological signals during formation and regression of the rat corpus luteum.

The corpus luteum (CL) is a transient endocrine organ that secretes progesterone to support pregnancy. The CL is formed from an ovulated follicle in a process that involves extensive angiogenesis and tissue remodeling. If fertilization does not occur or implantation is unsuccessful, the CL will undergo regression, which involves extensive tissue degradation. Extracellular proteases, such as serine proteases and matrix metalloproteinases (MMPs), are thought to play important roles in both the formation and regression of the CL. In this study, we have examined the physiological regulation pattern and cellular distribution of messenger RNAs coding for gelatinase A (MMP-2), collagenase-3 (MMP-13), membrane type MMP 1 (MT1-MMP, MMP-14), and the major MMP inhibitor, tissue inhibitor of MMPs type 1 (TIMP-1) in the CL of adult pseudopregnant (psp) rat. Northern blot and in situ hybridization analyses revealed that gelatinase A messenger RNA was mainly expressed during luteal development, indicating that gelatinase A may be associated with the neovascularization and tissue remodeling that takes place during CL formation. Collagenase-3 had a separate expression pattern and was only expressed in the regressing CL, suggesting that this MMP may be related with luteal regression. MT1-MMP that in vitro can activate progelatinase A and procollagenase-3 was constitutively expressed during the formation, function, and regression of the CL and may therefore be involved in the activation of these MMPs. TIMP-1 was induced during both the formation and regression of the CL, suggesting that this inhibitor modulates MMP activity during these processes. To test whether the induction of collagenase-3 and TIMP-1 is coupled with luteal regression, we prolonged the luteal phase by performing hysterectomies, and induced premature luteal regression by treating the pseudopregnant rats with a PGF2alpha analog, cloprostenol. In both treatments, collagenase-3 and TIMP-1 were induced only after the serum level of progesterone had decreased, suggesting that collagenase-3 and TIMP-1 are induced by physiological signals, which initiate functional luteolysis to play a role in tissue degradation during structural luteolysis. In conclusion, our data suggest that gelatinase A, collagenase-3, and MT1-MMP may have separate functions during the CL life span: gelatinase A mainly takes part in CL formation, whereas collagenase-3 mainly takes part in luteal regression; MT1-MMP is constitutively expressed during the CL life span and may therefore serve as an in vivo activator of both gelatinase A and collagenase-3. TIMP-1 is up-regulated both during the formation and regression of the CL and may therefore regulate MMP activity during both processes.

Animals↗
PubMed1999

Rat dentin matrix protein 3 is a compound protein of rat dentin sialoprotein and phosphophoryn.

During cloning of the rat incisor phosphophoryn gene, several clones were identified with a PP antibody. One of the clones (2PP) was shown to encode a PP denoted as dentin matrix protein 2, DMP2. We have now sequenced another clone, which appears to be bifunctional, or at minimum, has two distinct domains. The 5' region encodes for dentin sialoprotein (DSP), while the 3' region encodes a small or "mini" PP. There is no stop codon between these domains. The whole gene has been named Dmp3, in keeping with the current nomenclature adopted in our laboratory. The previously reported Dmp2 gene does not encode a DSP domain but has a 114 amino acid carboxy terminal sequence identical except for a single residue with that of the DMP3. Thus, Dmp2, Dmp3 and their corresponding proteins, probably represent related members of a multigene family. There is no evidence for differential splicing. Since the DSP isolated from dentin does not carry the mini-PP domain, it must be cleaved postranslationally from DMP3.

Amino Acid Sequence↗
PubMed1999

The effective dose of dexamethasone for antiemesis after major gynecological surgery.

UNLABELLED: This double-blind, randomized, placebo-controlled study evaluated the minimum effective dose of dexamethasone for postoperative antiemesis. One-hundred fifty women scheduled for major gynecological surgery were randomly assigned to receive dexamethasone 10 mg (D10), 5 mg (D5), 2.5 mg (D2.5), 1.25 mg (D1.25), or placebo (P) before the induction of general anesthesia. A standardized general anesthesia technique was used. Postoperative pain was treated with bolus IV doses of morphine via a patient-controlled analgesia device. Patients were assessed for incidence of vomiting at 4, 8, 12, and 24 h after surgery. A total of 6, 6, 8, 15, and 19 patients in Groups D10, D5, D2.5, D1.25, and Group P experienced vomiting at least once within the first postoperative 24 h, respectively. Dexamethasone 10 mg, 5 mg, and 2.5 mg was more effective than dexamethasone 1.25 mg or placebo for antiemesis (P < 0.05). The difference in antiemetic effect among the 10 mg, 5 mg, and 2.5 mg groups was similar. The results suggest that 2.5 mg is the minimum effective dose of dexamethasone for postoperative antiemesis in patients undergoing general anesthesia for major gynecological surgery. IMPLICATIONS: Although dexamethasone is effective for antiemesis, major side effects may accompany its perioperative use. To achieve the best antiemesis with the fewest side effects, dexamethasone 10 mg, 5 mg, 2.5 mg, and 1.25 mg were compared with placebo in surgical patients. We found 2.5 mg to be the minimum effective dose without discernible side effects.

Anesthesia, General↗
PubMed1999

Evidence for an inactive transposable mariner-like element in Anopheles albimanus.

Transposable elements may eventually be used as transformation vectors of anti-Plasmodium genes in natural populations of Anopheles mosquitoes. The mariner transposable element is widespread in most animal phyla and we wished to test for its presence in the important Latin American malaria vector, Anopheles albimanus. Degenerate primers were designed from the consensus of insect mariner elements and used in a polymerase chain reaction to amplify a fragment of the predicted size from An. albimanus. The fragment was cloned, sequenced, and determined to be a mariner-like element through multiple alignment with known insect mariner elements. Dot blot and Southern blot analyses showed only one or a few elements per haploid genome. The cloned fragment was used as a probe to isolate similar sequences from an An. albimanus genomic DNA library. A 659-base-pair clone was 57% similar at the DNA level with mariner elements from Anopheles gambiae, Chrysoperla ptorapunda, and Haematobia irritans. This low sequence similarity is comparable to that found among mariner-like elements in all insects. However, conserved amino acid motifs were not discovered nor was a single open reading frame found. These aspects suggest that the An. albimanus mariner-like element may represent an ancient transposition event but that the element is no longer active, the typical open reading frame having been disrupted through nucleotide insertions and deletions.

Animals↗