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T Tsai

Publications and source records attributed to T Tsai.

At least 19 recordsLinked to original sources
PubMed2002

Chiari-II malformation: a biometric analysis.

INTRODUCTION: Chiari-II malformation is a complex set of anatomic abnormalities of the posterior fossa, brainstem, and cerebellum seen in myelomeningocele. Previous studies have tried to understand this condition and its clinical consequences by studying a few fixed anatomic landmarks as dependent variables and clinical symptoms as outcome variables. These studies have led to conflicting and limited results. As a first step towards a more comprehensive study of the structural-functional relationships in Chiari-II malformation, we undertook a biometric case-series analysis of a group of individuals with MMC, using both traditional methods to study size, and thin-plate spline methodology to study shape. MATERIALS AND METHODS: The traditional analysis was a retrospective, randomly obtained case-series of 25 individuals with myelomeningocele and Chiari-II malformation. MRIs were digitized for biometric analysis of the component structures and compared to 25 controls. Landmarks on the digitized images were measured using Scion Image. Data were statistically analyzed using SPSS. The thin-plate spline analysis used a subset of these individuals (n = 14). Landmarks on digitized MRIs were identified and marked with TPSDig software. Landmark data was then imported into Splus to generate a series of shape variables. Statistical analysis using Splus was then undertaken. RESULTS: Traditional analysis revealed relationships between vermian herniation and pontomedullary junction position (p < 0.05) as well as between the height (and overall size) of the posterior fossa and degree of vermian herniation (p < 0.05). The degree of brainstem herniation/elongation did not correlate with the degree of vermian herniation. The shape analysis revealed that there is as much shape variability within the group of Chiari-II patients as there is between this group and unaffected controls. Thin-plate spline analysis shows that the position of the caudal-most aspect of the vermis is the point of greatest brain rearrangement; likewise, the opisthion is the point of greatest bony rearrangement. Partial least-squares analysis shows that in Chiari-II patients, a strong correlation (r = 0.821) exists between the extent to which the brain is warped (specifically, in regard to vermian descent) and the extent to which the bone is warped (specifically, in regard to the displacement of the opisthion) (p < 0.05). CONCLUSION: Traditional biometric analysis of size confirms that the degree of vermian herniation and cervicomedullary junction herniation are independent variables in Chiari-II malformation. Posterior fossa size is an important factor in explaining the variability of vermian herniation. The relationship between IPN position and vermian herniation suggests the possibility of a common etiology. The phenomenon of cervicomedullary junction descent appears to be independent, suggesting a different etiology. Analysis of shape indicated that shape changes in bone and brain are related, and that the Chiari-II-associated abnormalities vary greatly in their degree of abnormality. The extreme morphological variability argues against the use of mean differences as a statistical technique in analyzing morphological abnormalities in the structures we investigated.

Adolescent↗
PubMed2001

La Crosse encephalitis in children.

BACKGROUND: La Crosse encephalitis is a mosquito-borne disease that can be mistaken for herpes simplex encephalitis. It has been reported in 28 states but may be underrecognized. METHODS: We investigated the manifestations and clinical course of La Crosse encephalitis in 127 patients hospitalized from 1987 through 1996. The diagnosis was established by serologic testing for IgM and IgG antibodies to La Crosse virus. Data were collected by chart review. RESULTS: Most of the patients were school-aged children (mean [+/-SD] age, 7.8+/-3.5 years; range, 0.5 to 15.0). Symptoms included headache, fever, and vomiting (each in 70 percent or more of the patients), seizures (in 46 percent), and disorientation (in 42 percent). Thirteen percent had aseptic meningitis. Hyponatremia developed in 21 percent, and there were signs of increased intracranial pressure in 13 percent. Six patients, including three with cerebral herniation, underwent intracranial-pressure monitoring. The 13 patients (11 percent) whose condition deteriorated in the hospital had decreases in serum sodium levels (P=0.007), and increases in body temperature (P=0.003) at the time of deterioration. At admission, these patients more often had a history of vomiting (P=0.047) and a score of 12 or lower on the Glasgow Coma Scale (P=0.02) than the others; a trend toward a greater prevalence of seizures at admission was also evident in this group (P=0.07). All the patients survived, but 15 of them (12 percent) had neurologic deficits at discharge. Follow-up assessments, performed in 28 children, suggested an increase in cognitive and behavioral deficits 10 to 18 months after the episode of encephalitis. CONCLUSIONS: La Crosse virus infection should be considered in children who present with aseptic meningitis or encephalitis. Hyponatremia and increasing body temperature may be related to clinical deterioration.

Adolescent↗
PubMed2001

Sustained-release effect of codried excipients of microcrystalline cellulose and Ganoderma fiber.

The sustained-release effects of codried excipient of modified Ganoderma (treated with alkaline solution) and microcrystalline cellulose at different ratios were examined using acetaminophen (ACT) as a model drug. Results demonstrate that the crushing strength of most ACT tablets made with codried powder at all ratios increased as compaction force increased; but a rapid decline was observed when compression force exceeded 2 tons. Drug release from tablets compressed at 0.5 ton increased as modified Ganoderma fiber content increased. But when the compression force exceeded 1 ton, the release rate was not influenced by the compaction force or the increasing content of Ganoderma fiber. However, the dissolution of ACT from these tablets could be sustained for longer than 24 h. The extent of drug release was shown to increase with increasing amounts of modified Ganoderma in the codried excipient. The addition of disintegrants could further accelerate the drug release from the tablet. Drug release was also dependent upon the amount and kind of disintegrant used. The influence was in the following order: primojel>crospovidone>starch 1500.

Acetaminophen↗
PubMed2001

Implications of increased left ventricular mass index on in-hospital outcomes in patients undergoing aortic valve surgery.

BACKGROUND: Increased left ventricular mass index has been shown to be associated with higher mortality in epidemiologic studies. However, the effect of increased left ventricular mass index on outcomes in patients undergoing aortic valve replacement is unknown. METHODS: We studied 473 consecutive patients undergoing elective aortic valve replacement to assess the influence of left ventricular mass index on outcomes in patients having this procedure. Echocardiographic left ventricular dimensions were used to calculate left ventricular mass index (considered increased if >134 g/m(2) in male patients and >110 g/m(2) in female patients). RESULTS: Left ventricular mass index was increased in 24% of patients undergoing aortic valve replacement. Postprocedural complications (respiratory failure, renal insufficiency, congestive heart failure, and atrial and ventricular arrhythmias), length of stay in the intensive care unit, and in-hospital mortality were increased in patients with increased left ventricular mass index. Multivariable analysis identified prior valve surgery (odds ratio, 4.3; 95% confidence interval, 1.2-15.7; P =.030), left ventricular ejection fraction (odds ratio, 1.07; 95% confidence interval, 1.01-1.14; P =.020), history of hypertension (odds ratio, 8.2; 95% confidence interval, 2.2-30.4; P =.002), history of liver disease (odds ratio, 50.4; 95% confidence interval, 4.2-609.0; P =.002), and increased left ventricular mass index (odds ratio, 38; 95% confidence interval, 9.3-154.1; P <.001) as independent predictors of in-hospital mortality. Furthermore, low output syndrome was identified as the most common mode of death (36%) after aortic valve replacement in patients with increased left ventricular mass index. CONCLUSIONS: Increased left ventricular mass index is associated with increased adverse in-hospital clinical outcomes in patients undergoing aortic valve replacement. Although this finding warrants special modification in perioperative management, further studies are needed to address whether outcomes in asymptomatic patients with aortic valve disease could be improved by earlier aortic valve replacement before a significant increase in left ventricular mass index.

Aortic Valve↗
PubMed2001

The effect of simulated birth trauma and/or ovariectomy on rodent continence mechanism. Part I: functional and structural change.

PURPOSE: We examined the changes in the lower urinary tract after delivery, intravaginal ballooning and/or ovariectomy. MATERIALS AND METHODS: The study included 10 virgin and 48 primiparous pregnant rats. Cystometry and the stress/sneeze test were performed in virgin and postpartum rats shortly after delivery and at 8 weeks before sacrifice. Half of the delivered animals underwent intravaginal balloon dilation. Four weeks later half in each group underwent ovariectomy. The rats were subdivided into group 1--delivery, group 2--delivery plus balloon inflation, group 3--delivery plus ovariectomy and group 4--delivery plus balloon inflation plus ovariectomy. Tissues from the bladder, bladder neck, urethra and levator were collected, analyzed by electron microscopy, and immunostained for caveolin-1, caveolin-3 and neuronal nitric oxide synthase. RESULTS: Higher bladder capacity was detected in postpartum than in virgin rats. Urine leakage on stress/sneeze testing increased significantly in groups 2 and 4. Electron microscopy revealed a significant decrease in sarcolemma caveolae in the smooth muscle of the bladder and urethra in groups 2 to 4. In the bladder neck in group 3 caveolae were increased in smooth muscle. In groups 2 to 4 in the smooth muscle of the bladder and urethra caveolin-1 was significantly decreased. Caveolin-3 and neuronal nitric oxide synthase in striated muscle also significantly decreased in groups 2 to 4. CONCLUSIONS: These findings suggest that birth trauma simulated by ballooning and ovariectomy may contribute to stress urinary incontinence. The alteration in smooth muscle caveolae as well as the membrane protein caveolin may have a role in functional alterations caused by birth trauma and ovariectomy.

Animals↗
PubMed2000

Cell cycle regulatory gene abnormalities are important determinants of leukemogenesis and disease biology in adult acute lymphoblastic leukemia.

To test the hypothesis that cell cycle regulatory gene abnormalities are determinants of clinical outcome in adult acute lymphoblastic leukemia (ALL), we screened lymphoblasts from patients on a Southwest Oncology Group protocol for abnormalities of the genes, retinoblastoma (Rb), p53, p15(INK4B), and p16(INK4A). Aberrant expression occurred in 33 (85%) patients in the following frequencies: Rb, 51%; p16(INK4A), 41%; p53, 26%. Thirteen patients (33%) had abnormalities in 2 or more genes. Outcomes were compared in patients with 0 to 1 abnormality versus patients with multiple abnormalities. The 2 groups did not differ in a large number of clinical and laboratory characteristics. The CR rates for patients with 0 to 1 and multiple abnormalities were similar (69% and 54%, respectively). Patients with 0 to 1 abnormality had a median survival time of 25 months (n = 26; 95% CI, 13-46 months) versus 8 months (n = 13; 95% CI, 4-12 months) for those with multiple abnormalities (P <.01). Stem cells (CD34+lin-) were isolated from adult ALL bone marrows and tested for p16(INK4A) expression by immunocytochemistry. In 3 of 5 patients lymphoblasts and sorted stem cells lacked p16(INK4A) expression. In 2 other patients only 50% of sorted stem cells expressed p16(INK4A). By contrast, p16 expression was present in the CD34+ lin- compartment in 95% (median) of 9 patients whose lymphoblasts expressed p16(INK4A). Therefore, cell cycle regulatory gene abnormalities are frequently present in adult ALL lymphoblasts, and they may be important determinants of disease outcome. The presence of these abnormalities in the stem compartment suggests that they contribute to leukemogenesis. Eradication of the stem cell subset harboring these abnormalities may be important to achieve cure.

Adolescent↗
PubMed2000

Endometrial stripe thickness in tubal and intrauterine pregnancies.

OBJECTIVE: To evaluate endometrial stripe thickness (EST) among patients with tubal pregnancy (TP) and intrauterine pregnancy (IUP). DESIGN: Historical cohort. SETTING: City hospital. PATIENT(S): Ninety-four women suspected to have TP. INTERVENTION(S): Serum betaHCG and sonographic EST measurements. MAIN OUTCOME MEASURE(S): Comparison of age, gestational age (GA), EST, and log beta HCG. RESULT(S): The two groups of women, 65 with TP and 29 with IUP, had similar mean ages (+/-SD) of 28.6 +/- 5.7 and 28.6 +/- 6.1, respectively. The median values of GA in the 2 groups were similar, 46.6 and 44.6 d, respectively. The mean values for EST (+/-SD), adjusted for GA, were significantly different: 9.9 +/- 5.9 mm in the TP group and 12.6 +/- 5.3 mm in the IUP group. The mean values (+/-SD) of log beta HCG in the 2 groups also differed significantly: 6.90 +/- 1.29 and 7.52 +/- 0.97, respectively. No correlation was found between EST and GA or log beta HCG within either group. CONCLUSION(S): The mean EST in women with TP was significantly smaller than in women with IUP. The wide range of EST values and their overlap precludes the utilization of EST as a single feature in the diagnosis of a tubal pregnancy.

Adult↗
PubMed2000

Peptide analogs from E-cadherin with different calcium-binding affinities.

Cadherins are a family of calcium-dependent cell-surface proteins that are fundamental in controlling the development and maintenance of tissues. Motif B of E-cadherin seems to be a crucial calcium-binding site as single point mutations (D134A and D134K) completely inactivate its adhesion activity. We analyzed peptide models corresponding to motif B (amino acids 128-144) as well as selected mutations of this motif. Our NMR studies showed that this motif B sequence is actually an active calcium-binding region, even in the absence of the rest of the cadherin molecule. We found that the binding affinity of this motif is very sensitive to mutations. For example, our peptide P128-144 with the native calcium-binding sequence has an affinity of Kd 0.4 mM, whereas the mutants P128-144/ D134A and P128-144/D134K containing the replacement of Asp134 by Ala and Lys, have Kd values of only 1.5 and 11 mM, respectively. Removing Asp at position 134, which correlates with the loss of adhesion activity, decreases calcium-binding affinity 20-fold. Ala132, along with residues Asp134, Asp136 and Asn143, is involved in calcium binding in solution. We also demonstrated that the calcium-binding affinity can be increased 3-fold when an additional Asp is introduced at position 132. In 50% organic solvent, this binding affinity of peptide P128-144/A132D (17-mer) from E-cadherin is similar to that of peptide P72-100/C73-77-91A (29-mer) from alpha-lactalbumin.

Amino Acid Sequence↗
PubMed2000

Genomic structure and chromosome location of the mouse RelA p65 gene (Rela).

The RelA (p65) subunit of transcription factor NF-kappaB plays a critical role in development, and rela(-/-) knockout mice die in utero from massive liver apoptosis. Only partial sequences of the mouse Rela gene are available. We have determined the genomic structure of mouse Rela and promoter, and have mapped the gene to chromosome 19B1-3.

Animals↗
PubMed1999

Clinical findings and outcomes of intra-hemodialysis cardiopulmonary resuscitation.

Renal failure with severe uremia is still an important cause of mortality, despite effective renal replacement therapy. Cardiopulmonary arrest (CPA) is the most severe complication during hemodialysis (HD). To acquire more information about cardiopulmonary resuscitation (CPR) during HD, we retrospectively enrolled 24 patients (11 males and 13 females) who had CPR during HD in a medical center during a 3-year period. Their mean age was 66.8 +/- 16.8 years. The CPR rate of the patients from our outpatient department (0.02%) was significantly lower than that from general wards (0.11%), the intensive care unit (ICU, 0.16%), or the emergency room (ER, 0.38%). Eighteen patients (75%) were initially resuscitated successfully. Only 11 patients (45.8%) survived more than 24 h after CPR, and 2 patients (8.3%) survived more than 1 month, but none survived until discharge. The rates of surviving 24 h and surviving to discharge during HD were lower than those in the general wards, the ICU or the ER. Sepsis (33.3%) and cardiogenic shock (25%) were the two leading causes of death. For analyzing factors affecting the outcome of CPR, we divided the patients into 2 groups by survival time (<==24 vs. >24 h). Patients with heart disease or with prolonged CPR durations (>30 min) had shorter survival. No significant survival difference between the 2 groups was found due to factors of age, sex, diabetic nephropathy, pre-arrest morbidity scores, pre-arrest laboratory data, renal failure pattern, HD duration, the preceding HD time and ultrafiltrated volume.

Aged↗
PubMed1998

Film-forming polymer-granulated excipients as the matrix materials for controlled release dosage forms.

Lactose and dibasic calcium phosphate (DCP) were granulated with various concentrations of film-forming polymers by a stepwise spraying method to prepare a directly compressible matrix excipient. The film-forming polymeric latex of Eudragit RS-30D, Eudragit RL-30D, and Surelease (ethylcellulose) were used in this study as the source of the granulating materials. Better flowability and compressibility were observed for all the granulated particles than the polymer-free granules. Most tablets prepared from the polymer-granulated particles exhibited satisfactory friability of less than 1% except for those prepared from lactose particles granulated with low concentrations of ethylcellulose and from plain lactose granules. Change in tensile strength and tablet thickness were in good agreement with the plasticity of the granulating polymer. Polymer-granulated lactose and DCP provided for controlled release of captopril from matrix tablets. This investigation suggests that conventional excipients can be modified by a simple granulating procedure to provide better physical properties for being used as a matrix material.

Acrylic Resins↗
PubMed1998

Modification of physical characteristics of microcrystalline cellulose by codrying with beta-cyclodextrins.

In an attempt to modify the physical properties of microcrystalline cellulose (MCC), the slurry form of this material was codried with beta-cyclodextrin (beta-CD). MCC slurry was blended with beta-CD at concentrations of 10%-50% w/w as a dried mass relative to MCC. The mixtures were then granulated with water and codried at 60 degrees C for 12 h or until a constant weight was reached. Codried granules were pulverized, and the fraction between 61 and 150 microns in size was reserved. The powder and tableting properties of the codried products were compared to those of various grades of MCC and the corresponding components and physical mixtures. The results showed that the products of MCC codried with beta-CD significantly improved the flowability of MCC powder. It is probable that the improved flowability was due to the more rounded shape of particles formed with this codried process, which was confirmed by SEM photographs. Moreover, the compactibility and disintegration properties of tablets produced from the codried products were even better than those using MCC alone, physical mixtures, or various grades of MCC. MCC in a slurry form was more efficient than the existing MCC products in achieving these results, which is postulated to be due to the greater amount of water required and the higher solubility of beta-CD in water promoting the interaction between beta-CD and MCC during granulation. In conclusion, MCC codried with beta-CD provides a useful excipient for direct compression.

Cellulose↗
PubMed1997

Unilateral rotational path removable partial dentures for tilted mandibular molars: design and clinical applications.

This article describes the design of a unilateral rotational path removable partial denture to restore a single edentulous space with a tilted mandibular molar. It is modified from an original bilateral rotational path design and consists of several components, which are (1) the rotation axis, (2) the long occlusal rest, (3) the short bracing arms, (4) the rigid retainer and extended proximal plates, (5) the conventional direct retainer assembly, and (6) optional auxiliary rest. The stability and retention of the denture are controlled anteriorly by the buccal retentive clasp and lingual guide plate of the conventional direct retainer, and posteriorly by the rigid retainer and its buccally and lingually extended proximal plates. The clinical results of the dentures used in strictly selected situations are excellent; however, it is emphasized that a unilateral denture is only an alternative rather than a routine application. The risk of accidental aspiration is also of concern.

Deglutition↗
PubMed1997

Allogeneic bone marrow transplantation in patients who relapse after autologous transplantation.

Increasing numbers of patients have received autologous stem cell transplants (ASCT) for hematologic malignancies. Since only a fraction of these patients are cured, physicians are more frequently faced with the dilemma of how to manage relapse post-transplant. Potential advantages of allogeneic transplantation (alloBMT) over ASCT include lack of graft tumor contamination and presence of a graft-versus-tumor effect. For this reason, patients who relapse after ASCT are often considered candidates for allogeneic bone marrow transplantation. However, there is limited knowledge on the outcome of alloBMT in patients who relapse after ASCT. We retrospectively analyzed the outcome of 20 patients with malignant lymphoma (n = 14) and AML (n = 6) who underwent alloBMT after failing an ASCT. The median age was 30 (17-41) years and the interval from ASCT to alloBMT was 10.5 (2-25) months. Seventeen patients died between 0.3 to 11 months (median 2.0) after alloBMT, all due to BMT-related toxicities. Three patients remain alive and free of disease at 1.1, 1.2 and 2.5 years after alloBMT. Sixteen of the 18 evaluable patients (89%) developed grade II-IV acute GVHD. Patients undergoing alloBMT after ASCT have a very high treatment-related mortality and incidence of grade II-IV acute GVHD. Alternative treatments with salvage chemotherapy, radiation or investigational approaches should be considered in patients who relapse after ASCT.

Adolescent↗
PubMed1997

Epidemic Venezuelan equine encephalitis in La Guajira, Colombia, 1995.

In 1995, the first Venezuelan equine encephalitis (VEE) outbreak in Colombia in 22 years caused an estimated 75,000 human cases, 3000 with neurologic complications and 300 fatal, in La Guajira State. Of the state's estimated 50,000 equines, 8% may have died. An epizootic IC virus, probably introduced from Venezuela, was rapidly amplified among unvaccinated equines. Record high rainfall, producing high densities of vector Aedes taeniorhynchus, led to extensive epidemic transmission (30% attack rate) in the four affected municipalities. Native Wayuu Indians, constituting 24% of the state's population, were at increased risk of infection (risk ratio, 3.3; 95% confidence interval, 2.2-5.3). Epidemiologic studies found no evidence of human-to-human transmission. A higher-than-expected number of abortions during the outbreak confirmed a previously suspected abortifacient role of VEE infection. Pesticide applications and a mass equine vaccination program contributed to preventing the outbreak's spread south of La Guajira.

Adult↗
PubMed1996

Period protein is necessary for circadian control of egg hatching behavior in the silkmoth Antheraea pernyi.

We examined the molecular basis of the circadian control of egg hatching behavior in the silkmoth Antheraea pernyi. Egg hatching is rhythmically gated, persists under constant darkness, and can be entrained by light by midembryogenesis. The time of appearance of photic entrainment by the silkmoth embryo coincides with the appearance of Period (PER) and Timeless (TIM) proteins in eight cells in embryonic brain. Although daily rhythms in PER and/or TIM immunoreactivity in embryonic brain were not detected, a robust circadian oscillation of PER immunoreactivity is present in the nuclei of midgut epithelium. per antisense oligodeoxynucleotide treatment of pharate larvae on the day before hatching consistently abolishes the circadian gate of egg hatching behavior. per antisense treatment also causes a dramatic decrease in PER immunoreactivity in newly hatched larvae. The results provide direct evidence that PER is a necessary element of a circadian system in the silkmoth.

Animals↗
PubMed1996

Tumor suppressor gene alteration in adult acute lymphoblastic leukemia (ALL). Analysis of retinoblastoma (Rb) and p53 gene expression in lymphoblasts of patients with de novo, relapsed, or refractory ALL treated in Southwest Oncology Group studies.

To examine the impact of inactivation of tumor suppressor genes on outcome in adult ALL, we compared two groups of patients registered to SWOG treatment protocols for loss of the Rb gene product and p53 overexpression: (1) 89 patients with de novo ALL, and (2) 26 patients with relapsed/refractory ALL. The groups were comparable with respect to age, sex, and race. Cell lysates (> or = 80% blasts) were analyzed by immunoblotting which enabled detection of Rb or p53 proteins in as little as 1 microg of lysate. Loss of Rb expression (pRbneg) was found in 54/85 (64%) de novo and 11/19 (58%) relapsed patients (P = 0.79). Overexpression of p53 (p53abn), indicative of p53 point mutations, was found in 16/75 (21%) de novo and 8/19 (42%) relapsed patients (P = 0.08). Using a nonisotopic RNase cleavage assay, p53 point mutations in exons 5-9 were confirmed in 14/23 (61%) p53abn specimens. For the de novo ALL group, patients with normal Rb protein had higher WBC and higher peripheral blast and lymphocyte counts. Otherwise neither abnormal Rb or p53 expression correlated with any of a large panel of clinical and laboratory variables including FAB class, blast lineage, expression of myeloid antigens or CD34, and presence of the Ph1 chromosome or BCR-ABL. Analyses of treatment outcomes demonstrated no significant impact of Rb or p53 status alone on CR rates, relapse-free or overall survival. An identical percentage (11%) of both de novo and relapsed/refractory patients had concurrent abnormalities of both Rb and p53 expression (pRbneg/p53abn). The survival curve of these patients suggests an increased rate of early death, but the number of patients in this group was small. Summarizing, (1) loss of Rb expression is common in adult ALL; (2) overexpression of p53 may be more frequent in relapsed/refractory than de novo adult ALL; and (3) although Rb or p53 alterations alone are not strong independent predictors of outcome, their concurrent expression may predict a poor response to therapy.

Adolescent↗