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Biomedical subjects

W M Liu

Publications and source records attributed to W M Liu.

At least 37 records · Page 2Linked to original sources
PubMed2001

Major complications of operative and diagnostic laparoscopy for gynecologic disease.

STUDY OBJECTIVE: To compare complication rates of diagnostic and operative laparoscopy. Design. Retrospective study (Canadian Task Force classification II-2). SETTING: One medical center and three teaching hospitals. PATIENTS: Six thousand four hundred fifty-one women with various indications for laparoscopic diagnosis and/or laparoscopic surgery from January 1994 through June 1999. INTERVENTION: Diagnostic and operative laparoscopies. MEASUREMENTS AND MAIN RESULTS: Forty-two major complications occurred that directly resulted in one death. One patient had stomach injury, 3 had major vessel injuries, 5 had ureter injuries, 10 had intestinal injuries, and 23 had bladder injuries. The overall complication rate for all laparoscopies was 0.65% (42/6451); however, it rose to 0.80% (39/4865) for operative laparoscopy compared with 0.19% for diagnostic laparoscopy (3/1586; p <0.001, Fisher's exact test). CONCLUSION: Laparoscopic surgery is appropriate for managing various gynecologic diseases and has an acceptable complication rate. However, operative laparoscopy should be performed carefully because its rate of complications is significantly higher than that of diagnostic laparoscopy, especially for laparoscopic-assisted vaginal hysterectomy. (J Am Assoc Gynecol Laparosc 8(1):68-73, 2001)

Catheterization↗
PubMed2001

Laparoscopic bipolar coagulation of uterine vessels to treat symptomatic myomas in women with elevated Ca 125.

STUDY OBJECTIVE: To assess laparoscopic bipolar coagulation of uterine vessels (LBCUV) for symptomatic myomas in women with elevated CA 125 (>35 U/ml). DESIGN: Prospective, longitudinal study (Canadian Task Force classification II-1). SETTING: Private practice, university-affiliated hospital. PATIENTS: Forty-six women (age 30-50 yrs) with symptomatic myomas and elevated CA 125 level. INTERVENTION: Laparoscopic bipolar coagulation of uterine vessels performed over 10 months. MEASUREMENTS AND MAIN RESULTS: All patients underwent successful LBCUV and coagulation of anastomotic site of uterine arteries with ovarian arteries without intraoperative complication. One, 3, and 6 months after treatment, respectively, 52.2%, 65.2%, and 71.7% of women reported improvement in menorrhagia, 19.6%, 45.7%, and 56.5% noted improvement in dysmenorrhea, and 6.5%, 16.1%, and 38.7% had improvement in bulk-related symptoms. Average reduction in uterine volume was 9.1%, 16.9%, and 38.3% and average reduction in dominant myoma was 12.1%, 23.9%, and 59.1% at those times; the average reduction of CA 125 in all patients was 39.8, 75.4, and 126.1U/ml. CONCLUSION: Symptoms were improved and uterine volume and dominant myoma were reduced by LBCUV. The CA 125 level fell during follow-up in 40 patients (87.0%). Improvement in symptoms, especially menorrhagia, and shrinkage of uterine volume and dominant myoma seemed to be more pronounced in women with decreased than in those without decreased CA 125 after treatment (p = 0.045). The CA 125 level may be a valuable indicator for monitoring the efficacy of LBCUV.

Adult↗
PubMed2001

Vaginal expulsion of submucous myomas after laparoscopic-assisted uterine depletion of the myomas.

STUDY OBJECTIVE: To determine the safety and side effects that may be caused by laparoscopic-assisted uterine depletion (LAUD) of submucous myomas. DESIGN: Retrospective chart review and follow-up (Canadian Task Force classification II-2). SETTING: University-affiliated tertiary referral center. PATIENTS: Five hundred twenty women with symptomatic myomas warranting surgical treatment, who wished to retain their uteri. INTERVENTION: Laparoscopic bipolar coagulation of uterine arteries and anastomotic sites of uterine arteries with ovarian arteries. MEASUREMENTS AND MAIN RESULTS: Postoperative sonographs showed submucous myomas in 53 (10.2%) women. During follow-up for a mean of 8.6 months very few complications occurred; however, nine women (1.7%) experienced vaginal expulsion of myomas from 2 weeks to 5 months postoperatively. Four of them were readmitted within 43 days with high fever and fetid discharge, and cervical cultures revealed heavy growth of Escherichia coli in three. Vaginal myomectomy was performed in six patients, and one woman passed the myoma spontaneously. Histopathologic studies of these nine specimens showed that two had infarction, three had coagulative necrosis, and four had degeneration. After treatment, all nine women had normal menstruation and their symptoms resolved during follow-up of at least 3 months. CONCLUSION: In our experience LAUD led to satisfactory symptomatic improvement and reduction in myoma volume and few complications. If vaginal expulsion of submucous fibroids can be viewed as a side effect, we should pay close attention to women with submucous myomas, especially within 2 months of LAUD. Otherwise, more dangerous complications could occur.

Adult↗
PubMed2001

Addition of laparoscopic uterine nerve ablation to laparoscopic bipolar coagulation of uterine vessels for women with uterine myomas and dysmenorrhea.

STUDY OBJECTIVE: To assess the effectiveness of laparoscopic uterine nerve ablation (LUNA) in women with dysmenorrhea caused by uterine myomas treated by laparoscopic bipolar coagulation of uterine vessels (LBCUV). DESIGN: Prospective, randomized, longitudinal study (Canadian Task Force classification II-1). SETTING: Private practice, university-affiliated hospital. PATIENTS: Eighty-five women with uterine leiomyomas and associated dysmenorrhea. INTERVENTION: Laparoscopic bipolar coagulation of uterine vessels with or without LUNA. MEASUREMENTS AND MAIN RESULTS: Of 85 patients who entered the study, 41 were assigned to undergo LBCUV-LUNA (group A), which was successful in 40 (97.6%). In 44 women assigned to have LBCUV only (group B), 43 (97.7%) underwent successful surgery. Eighty women completed 1-, 3-, and 6-month follow-up (38 group A, 42 group B). The groups did not differ significantly in age, history of abdominopelvic surgery, intraperitoneal adhesions, endometriosis, concomitant surgery, and operating time. Seven (18.4%) of 38 women in group A and 12 (28.6%) of 42 in group B experienced lower abdominal pain postoperatively. Acceptable pain was defined as a score of zero or 1: 31 and 30 women in groups A and B reported scores of zero; 3 and 2 reported scores of 1; 4 and 8 reported scores of 2; zero and 2 reported scores of 3; and no patients reported scores of 4. The frequency and severity of postoperative pain were less in group A than in group B (both p <0.05). The efficacy of both methods was almost equal in shrinking the uterus and dominant myoma, and in improving menorrhagia and bulk-related symptoms. Dysmenorrhea improvement was 84.2% and 61.9% in groups A and B at 3 months and 92.1% and 73.8% at 6 months, respectively. This was more significant in group A than in group B (p <0.05). CONCLUSION: Our results suggest that LUNA may decrease postoperative ischemic pain and improve dysmenorrhea associated with uterine myomas treated by LBCUV.

Adolescent↗
PubMed2001

What's missing from multicultural competency research: review, introspection, and recommendations.

Much of the multicultural counseling research has pointed out the need for counselors to become culturally competent to appropriately address the needs of an emerging diverse community. To date, however, this body of research has largely focused on counselor competencies, with little attention being given to the client perspective of multicultural counseling competencies. This article discusses the importance of integrating the client perspective within the historical context of the multicultural literature by examining client preferences and expectations, as well as the adequacy of the current empirical data. The authors also raise the issue of politics inherent in multiculturalism and discuss how this affects the research. A number of recommendations are made as a guide for future research.

Clinical Competence↗
PubMed2001

Surgical implications of pseudomonas aeruginosa necrotizing fasciitis in a child with acute lymphoblastic leukemia.

Necrotizing fasciitis caused by Pseudomonas aeruginosa is extremely rare. Only 4 cases were reported in the literature. The authors report the occurrence of P aeruginosa necrotizing fasciitis starting out as a vulval abscess in a girl before induction chemotherapy for acute lymphoblastic leukemia. To our knowledge, this is the second case described in association with leukemia. In this case, the outcome was favorable because of early surgical intervention, confirming the diagnosis. J Pediatr Surg 36:948-950.

Child, Preschool↗
PubMed2000

Laparoscopic bipolar coagulation of uterine vessels to treat symptomatic leiomyomas.

Laparoscopic bipolar coagulation of uterine vessels was performed in three women with symptomatic myomas who required conventional surgical treatment. Uterine size and dominant myoma size were assessed by ultrasonography before and after surgery. Both uterine arteries, as well as anastomosis zone of uterine arteries with ovarian arteries, were occluded in all three women. Surgery was uneventful, and patients were hospitalized for only 2 days. All women experienced improvement in symptoms with no complications. Postoperative ultrasound showed progressive reduction in size of the dominant myoma. A larger series and longer follow-up are required to evaluate long-term effects and to identify appropriate candidates.

Adult↗
PubMed2000

The development and initial validation of the Multicultural Environmental Inventory: a preliminary investigation.

This article describes the development and initial validation of the Multicultural Environmental Inventory (MEI). The MEI is an instrument designed to measure an individual's perceptions about the degree to which graduate counseling programs address multicultural issues within curriculum, supervision, climate, and research. This investigation was conducted using the data from 208 students and faculty from counseling psychology graduate programs across the United States approved by the American Psychological Association. By using techniques of exploratory factor analysis, a 4-factor solution was determined to account for the relationships among the items on the MEI. The instrument was modified from 53 to 27 items on the basis of the items' effectiveness in measuring the underlying constructs of interest, and internal consistency information is provided on the final revised instrument (MEI-R). The factors underlying the MEI-R are discussed within the context of a multicultural environment in graduate counseling programs, and directions for future research are considered.

Adult↗
PubMed2000

Modulated binding of SATB1, a matrix attachment region protein, to the AT-rich sequence flanking the major breakpoint region of BCL2.

The t(14,18) chromosomal translocation that occurs in human follicular lymphoma constitutively activates the BCL2 gene and disrupts control of apoptosis. Interestingly, 70% of the t(14,18) translocations are confined to three 15-bp clusters positioned within a 150-bp region (major breakpoint region or [MBR]) in the untranslated portion of terminal exon 3. We analyzed DNA-protein interactions in the MBR, as these may play some role in targeting the translocation to this region. An 87-bp segment (87MBR) immediately 3' to breakpoint cluster 3 was essential for DNA-protein interaction monitored with mobility shift assays. We further delineated a core binding region within 87MBR: a 33-bp, very AT-rich sequence highly conserved between the human and mouse BCL2 gene (37MBR). We have purified and identified one of the core factors as the matrix attachment region (MAR) binding protein, SATB1, which is known to bind to AT-rich sequences with a high propensity to unwind. Additional factors in nuclear extracts, which we have not yet characterized further, increased SATB1 affinity for the 37MBR target four- to fivefold. Specific binding activity within 37MBR displayed cell cycle regulation in Jurkat T cells, while levels of SATB1 remained constant throughout the cell cycle. Finally, we demonstrated in vivo binding of SATB1 to the MBR, strongly suggesting the BCL2 major breakpoint region is a MAR. We discuss the potential consequences of our observations for both MBR fragility and regulatory function.

Amino Acid Sequence↗
PubMed1999

HMG-I(Y) recognizes base-unpairing regions of matrix attachment sequences and its increased expression is directly linked to metastatic breast cancer phenotype.

Base-unpairing regions (BURs) contain a specialized DNA context with an exceptionally high unwinding propensity, and are typically identified within various matrix attachment regions. A BUR affinity column was used to purify a doublet of Mr 20,000 proteins from human breast carcinoma cells. These proteins were identified as the high-mobility group (HMG) protein, HMG-I, and its splicing variant, HMG-Y. We show that HMG-I(Y) specifically binds BURs. Mutating BURs so as to abrogate their unwinding property greatly reduced their binding affinity to HMG-I(Y). Numerous studies have indicated that elevated HMG-I(Y) expression is correlated with more advanced cancers and with increased metastatic potential. We studied whether the expression of HMG-I(Y) responds to signaling through the heregulin (HRG)-erbB pathway and the extracellular matrix. HMG-I(Y) expression was increased in MCF-7 cells after stable transfection with an HRG expression construct that led cells to acquire estrogen independence and metastasizing ability. A high level of HMG-I(Y) expression was detected in metastatic MDA-MB-231 cells, but the expression was virtually diminished, and the metastasizing ability was lost after cells were stably transfected with an antisense HRG cDNA construct. HMG-I(Y) was also decreased in MDA-MB-231 cells when treated with a chemical inhibitor for matrix metalloproteinase-9 that led to a reduction of invasive capability in vitro. The level of HMG-I(Y) expression, therefore, is dynamically regulated in human breast cancer cells in response to varying types of signaling that affect metastatic ability, including the HRG-erbB pathway and those from the extracellular matrix.

Antisense Elements (Genetics)↗
PubMed1999

Semiautomated typing of human papillomaviruses by restriction fragment length polymorphism analysis of fluorescence-labeled PCR fragments.

A simplified version of a PCR-based reductional restriction fragment length polymorphism (rRFLP) approach for typing of human papillomaviruses (HPVs) is described previously [Wang et al., 1997]. It is achieved by the use of a biotin-labeled primer in PCR which, on restriction digestion and staining, is associated with only a single restriction fragment. In this report, we describe a further development of the rRFLP approach with the use of a fluorescence-labeled primer in PCR and fragment detection by laser scanning in an automatic sequencer. HPV typing is achieved by computer-assisted matching of the fluorescence-labeled rRFLP patterns with a database of rRFLP patterns of all known anogenital HPV types. On analysis of the typing of 133 HPV-positive cases using this procedure, 20 different HPV types were detected in exfoliated cervical cells in PAP smear samples derived from Taiwanese women. The results indicate the existence of a heterogeneous population of HPV types in Taiwan. Although most cases were associated with the more common HPV types, a significant fraction (about 20%) of the HPV types detected was related to the less common genotypes, which are often not included in commercial kits available for HPV typing. The results indicate the importance of covering as many HPV types as possible in clinical HPV genotyping protocols.

Cervix Uteri↗
PubMed1998

Prediction and classification of domain structural classes.

Can the coupling effect among different amino acid components be used to improve the prediction of protein structural classes? The answer is yes according to the study by Chou and Zhang (Crit. Rev. Biochem. Mol. Biol. 30:275-349, 1995), but a completely opposite conclusion was drawn by Eisenhaber et al. when using a different dataset constructed by themselves (Proteins 25:169-179, 1996). To resolve such a perplexing problem, predictions were performed by various approaches for the datasets from an objective database, the SCOP database (Murzin, Brenner, Hubbard, and Chothia. J. Mol. Biol. 247:536-540, 1995). According to SCOP, the classification of structural classes for protein domains is based on the evolutionary relationship and on the principles that govern the 3D structure of proteins, and hence is more natural and reliable. The results from both resubstitution tests and jackknife tests indicate that the overall rates of correct prediction by the algorithm incorporated with the coupling effect among different amino acid components are significantly higher than those by the algorithms without using such an effect. It is elucidated through an analysis that the main reasons for Eisenhaber et al. to have reached an opposite conclusion are the result of (1) misusing the component-coupled algorithm, and (2) using a conceptually incorrect rule to classify protein structural classes. The formulation and analysis presented in this article are conducive to clarify these problems, helping correctly to apply the prediction algorithm and interpret the results.

Algorithms↗
PubMed1998

Shear numbers of protein beta-barrels: definition refinements and statistics.

The original definition of shear number for a beta-barrel is not unique if it contains one or more uneven beta-bulges. We define the shear number of a beta-barrel as the minimal change of residue numbers in the backbone direction for all closed paths on the beta-barrel. We also discuss how to overcome some computational difficulties. It is pointed out that some closed beta-sheets should not be considered as beta-barrels. The pertinent statistics obtained from a representative list of the Protein Data Bank entries are summarized. All beta-barrels have positive shear numbers, i.e. they are right-twisted. The shear numbers of most beta-barrels are even, but exceptions do exist. The sizes of beta-ladders in a beta-barrel vary significantly. Most beta-barrels contain uneven beta-bulges, which may have important biological functions.

Animals↗
PubMed1998

Singular points of protein beta-sheets.

Protein beta-sheets can be regarded as surfaces. Two surfaces can be connected along a common edge to form a larger surface, or two edges of a surface can coalesce to form a closed sheet such as a beta-barrel. Singular points are locations where these connections are not perfect. In protein beta-sheets, a singular point is characterized by a residue separating two beta-ladders. In this paper, we study the singular points of protein beta-sheets from the surface topologic viewpoint, summarize our search results from the protein structural data in the Protein Data Bank, and present examples where singular points are near the active sites and may contribute to forming the proper relative positions of catalytic residues.

Binding Sites↗
PubMed1998

Effects of haemopoietic growth factors in combination with etoposide on sister chromatid exchange frequencies in peripheral blood mononuclear cells.

Prior to work on the influence of dosing and scheduling of the drug etoposide in bone marrow cells, the DNA-damaging effects of three haemopoietic growth factors, either alone or in combination with etoposide, were investigated. Sister chromatid exchange (SCE) frequencies in phytohaemagglutinin-stimulated mononuclear cells of six normal volunteers were used as an indicator of DNA damage. The effects of three growth factors on SCEs were investigated at concentrations ranging between 0 and 100 ng/ml and those of etoposide alone, at concentrations varying between 0 and 2 microM. The effect of combinations of growth factor (GF) and etoposide were assessed at a 40-ng/ml concentration of each cytokine and at 0.4 microM etoposide. Results showed not only a dose-dependent rise in SCE frequency in cells treated with etoposide but also a cytokine effect. Stem-cell factor did not cause a significant change in SCE numbers. However, cytokines with activity at the progenitor cell level induced small but significant increases in SCE numbers at concentrations of 50 and 100 ng/ml (P < 0.001). Results of combination studies indicated a significant 60% increase in SCE numbers in cells treated with GF and etoposide as compared with etoposide alone (P < 0.00001). This finding suggests a sensitivity of peripheral blood mononuclear cells to SCE induction by GFs given either as single agents or in combination with etoposide.

Antineoplastic Agents, Phytogenic↗
PubMed1998

Phylogenetic evidence for the improved RNA higher-order structure in internal ribosome entry sequences of HCV and pestiviruses.

The strong requirement for a small segment of the 5'-proximal coding sequence of hepatitis C virus (HCV) is one of the most remarkable features in the internal initiation of HCV mRNA translation. Phylogenetic analysis and RNA folding indicate a common RNA structure of the 5' untranslated region (UTR) of HCV and the animal pestiviruses, including HCV types 1-11, bovine viral diarrhea (BVDV), border disease virus (BDV) and hog cholera (HoCV). Although the common RNA structure shares similar features to that proposed for the internal ribosome entry sequence (IRES) of picornavirus, phylogenetic evidence suggests four new tertiary interactions between conserved terminal hairpin loops and between the terminal hairpin loop of F2b and the short coding sequence for HCV and pestiviruses. We suggest that the higher-order structures of IRES cis-acting elements for HCV and animal pestivirus are composed of stem-loop structures B-C, domains E-H, stem-loop structure J and four additional tertiary interactions. The common structure of IRES elements for these viruses forms a compact structure by these tertiary interactions and stem stacking. The active structural core is centered in the junction domain of E-H that is also conserved in all members of picornaviruses. Our model suggests that the requirement for a small segment of the 5' coding sequence is to form the distinct tertiary structure that facilitates the cis-acting function of the HCV IRES in the internal initiation of the translational control.

5' Untranslated Regions↗
PubMed1998

Prediction of protein structural classes by modified mahalanobis discriminant algorithm.

We first discuss quantitative rules for determining the protein structural classes based on their secondary structures. Then we propose a modification of the least Mahalanobis distance method for prediction of protein classes. It is a generalization of a quadratic discriminant function to the case of degenerate covariance matrices. The resubstitution tests and leave-one-out tests are carried out to compare several methods. When the class sample sizes or the covariance matrices of different classes are significantly different, the modified method should be used to replace the least Mahalanobis distance method. Two lemmas for the derivation of our new algorithm are proved in an appendix.

Algorithms↗