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Biomedical subjects

Y R Chen

Publications and source records attributed to Y R Chen.

At least 91 records · Page 5Linked to original sources
PubMed1998

Suicidal thinking among adolescents with a history of attempted suicide.

OBJECTIVE: To examine the risk of suicidal plans and ideation, depression, and other factors (low self-esteem, loneliness, fatalism, pessimism) among adolescents with a lifetime history of attempted suicide. METHOD: A self-administered questionnaire was used in a school-based survey of five middle schools (grades 6 through 8) enrolling 6,400 students. Usable questionnaires were obtained from 5,423 (85.3%). Data were obtained on a wide range of constructs including recent and lifetime suicide attempts, recent and lifetime suicide plans, recent ideation, symptoms of DSM-IV major depression, self-esteem, pessimism, loneliness, and fatalism. RESULTS: Data on crude prevalence showed thoughts about death, wishing to be dead, thoughts of suicide, and suicide plans were all significantly higher among youths with a history of attempts. Suicidal thinking was related to being more lonely, more fatalistic, and more pessimistic, and to less self-esteem, in addition to depression and a history of attempts. Multivariate analyses revealed the strongest factors associated with current suicidal thinking were history of attempts (odds ratio [OR] = 3.50), depression (OR = 5.34), and recent life stress (OR = 2.64). Compared with youths with none of the factors examined, those with six or more were at extreme risk (OR = 67.87). CONCLUSIONS: The strong association between history of suicide attempts, current ideation, and depression indicates that past suicide attempts occur in the context of other signs of psychosocial dysfunction. Given the paucity of epidemiological data on the natural history of suicidal behaviors among youths, more epidemiological studies of the antecedents and consequences of the range of suicidal behaviors among children and adolescents are needed. Given the high risk of subsequent suicidal behaviors by youths who have attempted but not completed suicide, this constitutes a high-risk population on which future research should focus.

Adolescent↗
PubMed1998

Stability of diagnosis in bipolar disorder.

The study goals were: a) to determine factors associated with diagnostic change from bipolar disorder (BPD) to other disorders and vice versa and b) to focus on subjects with diagnostic changes specifically between BPD and schizophrenia. A total of 936 subjects with at least four hospitalizations within 7 years were identified from the hospital database to study the first goal. A subset of 443 subjects with initial and final diagnoses of bipolar disorder and/or schizophrenia was used for the second goal. Sixty-eight (28.9%) of 235 subjects with an initial diagnosis of BPD changed to another diagnosis, whereas 113 (16.1%) of 701 subjects with a non BPD diagnosis had a diagnostic change to BPD at a later episode. Only 8 of 43 subjects entering the study period with a diagnosis of schizoaffective disorder still had that diagnosis at the end of the period. Results suggest that diagnostic flux between BPD and other disorders, especially schizophrenia, is relatively frequent. Gender, ethnicity, and substance abuse/dependence have prominent roles in these diagnostic changes. Severity and variability of the course of illness and progression of concurrent substance use disorder are crucial to understanding diagnostic flow in BPD.

Adult↗
PubMed1998

The Le Fort I-palatal split approach for skull base tumors: efficacy, complications, and outcome.

The Le Fort I, split-palate approach provides intraoral surgical access to a region of the midline skull base ranging from the upper clivus to the second cervical vertebra. Although this approach provides perhaps the largest exposure of all the intraoral techniques, there is little concerning it in the literature. Furthermore, there are no detailed descriptions of case histories, complications, and outcome. The purpose of this study was to evaluate this procedure's effectiveness and identify associated complications as well as outcome. Seven cases of patients who underwent eight skull base surgeries using the Le Fort I, split-palate approach were evaluated retrospectively. Particular attention was paid to postoperative occlusion, speech, mouth opening, infection, tumor recurrence, postoperative recovery period, and viability of maxillary bone and teeth. Follow-up ranged from 4 months to 7 years with a mean of 3.9 years. Pathologic diagnoses included three chordomas (two recurrent), one recurrent meningioma, one liposarcoma, one chondrosarcoma, and one inflammatory mass. One patient with chordoma underwent a second operation using the same approach. No deaths or major neurologic problems related to the procedure occurred. One patient who had known local metastases at the time of operation died several months after surgery. All other patients are still living. Duration of hospital stay ranged from 5 to 53 days with a mean of 25.4 days. Postoperative complications included one case of meningitis with an associated cerebrospinal fluid leak, three cases of malocclusion, one case of velopharyngeal insufficiency, and one extracranial soft-tissue infection. The case of meningitis was successfully treated by antibiotics. The malocclusions were corrected by conservative treatment. No problems with mouth opening or bone or tooth viability occurred. Tumor recurred in both cases in which malignancy was involved, whereas only one recurrence was noted among the benign cases. It is concluded that the Le Fort I-palatal split technique is a relatively safe and effective means for approaching midline skull base tumors. Several modifications to the surgical protocol and surgical technique are detailed herein.

Adult↗
PubMed1998

D-Ribulose-5-phosphate 3-epimerase: cloning and heterologous expression of the spinach gene, and purification and characterization of the recombinant enzyme.

We have achieved, to our knowledge, the first high-level heterologous expression of the gene encoding D-ribulose-5-phosphate 3-epimerase from any source, thereby permitting isolation and characterization of the epimerase as found in photosynthetic organisms. The extremely labile recombinant spinach (Spinacia oleracea L.) enzyme was stabilized by DL-alpha-glycerophosphate or ethanol and destabilized by D-ribulose-5-phosphate or 2-mercaptoethanol. Despite this lability, the unprecedentedly high specific activity of the purified material indicates that the structural integrity of the enzyme is maintained throughout isolation. Ethylenediaminetetraacetate and divalent metal cations did not affect epimerase activity, thereby excluding a requirement for the latter in catalysis. As deduced from the sequence of the cloned spinach gene and the electrophoretic mobility under denaturing conditions of the purified recombinant enzyme, its 25-kD subunit size was about the same as that of the corresponding epimerases of yeast and mammals. However, in contrast to these other species, the recombinant spinach enzyme was octameric rather than dimeric, as assessed by gel filtration and polyacrylamide gel electrophoresis under nondenaturing conditions. Western-blot analyses with antibodies to the purified recombinant enzyme confirmed that the epimerase extracted from spinach leaves is also octameric.

Base Sequence↗
PubMed1998

Near-infrared reflectance analysis for predicting beef longissimus tenderness.

Near-infrared reflectance spectra (1,100 to 2,498 nm) were collected on beef longissimus thoracis steaks for the purpose of establishing the feasibility of predicting meat tenderness by spectroscopy. Partial least squares (PLS) analysis (up to 20 factors) and multiple linear regression (MLR) were used to predict cooked longissimus Warner-Bratzler shear (WBS) force values from spectra of steaks from 119 beef carcasses. Modeling used the combination of log(1/R) and its second derivative. Overall, absorption was higher for extremely tough steaks than for tender steaks. This was particularly true at wavelengths between 1,100 and 1,350 nm. For PLS regression, optimal model conditions (R2 = .67; SEC = 1.2 kg) occurred with six PLS factors. When the PLS model was tested against the validation subset, similar performance was obtained (R2 = .63; SEP = 1.3 kg) and bias was small (<.3 kg). Among the 39 samples in the validation data set, 48.7, 87.7, and 97.4% of the samples were predicted within 1.0, 2.0, and 3.0 kg, respectively, of the observed Warner-Bratzler shear force value. The optimal PLS model was able to predict whether a steak would have a Warner-Bratzler shear force value < 6 kg with 75% accuracy. The R2 of MLR model was .67, and 89% of samples were correctly classified (< 6 vs > 6 kg) for Warner-Bratzler shear force. These data indicate that NIR is capable of predicting Warner-Bratzler shear force values of longissimus steaks. Refinement of this technique may allow nondestructive measurement of beef longissimus at the processing plant level.

Animals↗
PubMed1998

Modulating effect of mitomycin or cisplatin on lymphokine-activated killer cell proliferation and antitumor activity to bladder cancer cell lines in vitro.

AIM: To study the effect of mitomycin (Mit) or cisplatin (Cis) on the proliferation of lymphokine-activated killer (LAK) cells in patients with transitional cell cancer of bladder and their cytolysis to bladder tumor cells. METHODS: LAK cell proliferation was assayed in the presence of Mit or Cis by cell counting. Bladder cancer cell lines BIU-87 and EJ were cultured as target cells and cytotoxicity of LAK cells was determined by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay. RESULTS: The proliferation of LAK cells induced by recombinant interleukin-2 (IL-2) was inhibited by Cis in a concentration-dependent manner and was decreased to 55.3% at 100 mg.L-1 compared with control at 96 h. The enhanced growth of the LAK cells was observed with Mit 5-10 mg.L-1 from 48 to 96 h. Cis 10 mg.L-1 increased the cytotoxicity against BIU-87 and EJ cells. CONCLUSION: Immunomodulatory effect of chemotherapeutic agents on LAK cell proliferation induced by IL-2 in patients with bladder cancer mainly depends on the drug itself.

Antibiotics, Antineoplastic↗
PubMed1998

Bilateral choroidal metastases as the initial presentation of a small breast carcinoma: a case report.

Most ocular tumors metastasize from systemic origins in breast carcinoma in females, and bronchial carcinoma in males. Here, we report a case of choroidal carcinoma metastasis from the breast with visual problems being the only initial manifestations. In this case, both eyes were involved at almost the same time, with initial manifestation of blurred vision which progressed to complete visual loss. At first, the patient was diagnosed with malignant melanoma, and enucleation of the right eye was performed in another hospital. However, the tumor had already metastasized rapidly to numerous organs, including the lungs, brain and bone, although it had not affected the liver. Clinical presentations were, therefore, not compatible with those of malignant melanoma, which has usually been reported to metastasize to the liver. Persistent hypercalcemia and raised carcinoembryonic antigen (CEA) concentrations prompted investigations into the possibility of systemic malignancy. A very small breast nodule was finally located by thorough physical examination, and a lumpectomy was performed. A detailed review of the histopathology showed the tumors from the breast and the right eye to have the same origin. Simultaneous bilateral choroidal metastases from other malignancies is not uncommon; however, it is quite rare for breast carcinoma to present with visual problems as a first manifestation. Detailed history taking and physical examination are therefore essential when searching for a primary tumor, so that appropriate therapy can be given earlier.

Adult↗
PubMed1998

Allogeneic peripheral blood stem cell transplantation and early detection of donor engraftment by polymerase chain reaction.

Patients with hematologic malignancy or severe aplastic anemia after myeloablative chemo- and radiotherapy were given granulocyte colony-stimulating factor (G-CSF)-mobilized, cryopreserved allogeneic peripheral blood stem cells (PBSCs) from 15 healthy donors who were either human leukocyte antigen (HLA)-matched siblings (n = 13) or haploidentical offspring (2). Polymerase chain reaction-amplified short tandem repeat genotyping was used for early confirmation of donor engraftment after PBSC transplantation (PBSCT). A standard cyclosporine A/methotrexate combination was used to prevent acute graft-versus-host disease (GVHD). All donors, including one in the third trimester of pregnancy, tolerated G-CSF administration and 3-day PBSC harvesting procedures well. Engraftment was prompt for all patients; it was verified using a panel of 12 human polymorphic short tandem repeat loci from bone marrow as early as 7 days posttransplantation. This status was maintained until relapse, when mixed chimerism was detected using the polymerase chain reaction. A minimum resurgence of recipient cells to 1% of the population was required to detect chimerism. The median times to recovery of the absolute neutrophil count to greater than 0.5 x 10(9)/L and the sustained platelet count to greater than 20 x 10(9)/L without transfusion were 10 and 12 days after PBSCT, respectively. Six patients experienced acute GVHD, Grade I in two patients and Grade II in four, including two HLA-haploidentical recipients. Chronic GVHD was noticed in three of the 11 patients who were followed for at least 100 days after PBSCT. Ten patients were still alive at the latest follow-up and have been disease free for a median of 278 days (range 60-671). Five patients died from causes other than graft failure: three from leukemia relapse and two from transplant-related complications. The results confirm that G-CSF can be safely administered to healthy donors and that engraftment after allogeneic PBSCT is fast and durable. Complete chimerism can be detected early by genomic analysis. PBSCT may offer an alternative to bone marrow transplantation.

Adolescent↗
PubMed1998

Primitive neuroectodermal tumor of the lingual nerve: a case report.

This is a report of a primitive neuroectodermal tumor (PNET) arising from the lingual nerve of a 5-year-old girl. Twelve months after surgical excision and postoperative chemotherapy, the patient remained alive without any evidence of recurrence or metastasis. The occurrence of PNETs in the head and neck region in children is rare. This is the first case report in the literature of a PNET originating from a cranial nerve in a child. Because of its aggressive nature and poor prognosis, aggressive surgical and medical treatment regimens are needed. Surgeons should be mindful to include PNET in the differential diagnosis of head and neck tumors.

Child, Preschool↗
PubMed1998

Polymorphisms of twelve short tandem repeat loci in a Taiwanese population and their application in parentage testing.

With the advancement of techniques in molecular biology, rapid, sensitive, and reliable methods of DNA typing for parentage testing have become available. In this study, we evaluated the usefulness of multiplex polymerase chain reaction (PCR) with 12 unlinked short tandem repeat (STR) loci for paternity testing in Taiwan. The genetic informativeness of this test was then compared with that of conventional human leukocyte antigen (HLA) analysis in 167 parentage studies. The 12 STR loci alone provided a cumulative power of exclusion of up to 0.9998. Paternity was excluded in 59 (35.3%) cases, including 40 of 112 paternity trios and 19 of 55 paternity duos. In the 40 trios in which paternity was excluded, a mean of 6 (range, 3-9) incompatible STR markers were in the 19 duos in which paternity was excluded, a mean of 4 (range, 1-8) incompatible STR markers were noted. In the 72 trios in which the alleged paternity could not be excluded, the mean probabilities of paternity (PP) were 90.6863% with HLA testing alone, 99.9847% with STR analysis alone, and 99.9972% with combined HLA and STR analysis. In the 36 duos in which the alleged paternity could not be excluded, the mean PPs were 81.4768% with HLA testing alone, 99.6124% with STR analysis alone, and 99.9145% with combined HLA and STR analysis. These results suggest that STR analysis is very powerful when used alone for paternity trio testing and when combined with conventional serologic HLA typing for duo parentage testing in the Taiwan population.

Chromosome Mapping↗
PubMed1997

Ritanserin in the treatment of cocaine dependence.

Sixty-five cocaine-dependent subjects were enrolled into a 10-week randomized, double-blind study to determine the safety and efficacy of the serotonin-2 receptor antagonist, ritanserin (10 mg/day), in reducing cocaine consumption and craving. All subjects also participated in a structured intensive outpatient psychosocial program. Seventy-three percent of the participants completed the treatment program and follow-up. Subjects experienced a significant reduction in craving: 66.4% and 32.5% for the placebo and ritanserin groups, respectively. These reductions in craving were not paralleled by substantial decreases in cocaine use. Self-reported cocaine use was less frequent in the placebo group; paradoxically, blood levels of its metabolite, benzoylecgonine, were also higher although insignificantly so. Generally, ritanserin was well tolerated but significantly prolonged the QTc interval on the electrocardiogram. This outpatient program is effective at maintaining cocaine-dependent individuals in treatment and reducing craving. Ritanserin (10 mg/day) is not an efficacious adjunct to psychosocial treatment for cocaine dependence.

Adult↗
PubMed1997

Massive intratumor hemorrhage in facial plexiform neurofibroma.

BACKGROUND: Plexiform neurofibromatosis is a feature of von Recklinghausen's disease. Head and neck lesions may produce varying degrees of cosmetic and functional deformity. However, life-threatening hemorrhage into facial plexiform neurofibromas has not been previously reported. METHOD: We report two patients with von Recklinghausen's disease who experienced massive hemorrhage into facial neurofibromas, one following a blunt injury and the other without a known initiating event. RESULTS: Conservative management did not stop the hemorrhage into facial neurofibromas in either instance. Surgical exploration was mandated for hemorrhage control and evacuation of blood clots. Hemostasis was attained by a combination of hypotensive anesthesia and chromic catgut suture ligatures. CONCLUSIONS: These case reports demonstrate a potentially lethal complication in patients with facial plexiform neurofibroma. Where a competent and experienced interventional neuroradiologist is not available, surgical exploration should be undertaken to control bleeding.

Adolescent↗
PubMed1997

Pneumosinus dilatans of the maxillary sinus: a report of two cases.

Two cases of the rare condition of pneumosinus dilatans of the maxillary sinus are presented. This is a rare differential diagnosis of a maxillary mass. The precise aetiology and pathogenesis is obscure. Because facial deformity may persist after construction of a naso-antral window alone, direct resection and reconstruction using bone grafts is recommended in addition to the creation of a naso-antral window, if required.

Adult↗
PubMed1997

Emotion recognition in autism: verbal and nonverbal information.

This study examined the roles of verbal and nonverbal sources of information in the ability of persons with and without autism to recognize emotion. Child, adolescent, and young adult participants in four groups [Lower Functioning Autism (LFA) (n = 17), High Functioning Autism (HFA) (n = 18), Lower Functioning Comparison (LFC) (n = 18), and High Functioning Comparison (HFC) (n = 23)] identified emotions shown (happy, angry, sad, surprised, or neutral) in video clips of individuals expressing emotion verbally, nonverbally, or both. Verbal expressions of emotion were either Explicit, Implicit, or Neutral, whereas nonverbal expressions were Animate or Flat (3 x 2). Pairwise ANCOVAs indicated no group differences between HFA and HFC groups or between the LFA and LFC groups, and indicated instead group differences between higher and lower functioning persons. With groups collapsed into High Functioning (HF) and Lower Functioning (LF), significant group differences were found. Performance of LF individuals suggested they had difficulty inferring how a person felt based on what the person said, if the emotion was not explicitly named. Performance of HF individuals suggested they relied more on nonverbal than on verbal information to determine a speaker's emotion, except where the emotion was explicitly named. Results suggested that persons with autistic spectrum disorders can use affective information from multiple sources in much the same ways as persons of comparable developmental level without autism.

Adolescent↗
PubMed1997

Ethnocultural differences in prevalence of adolescent depression.

Data from an ethnically diverse sample of middle school (Grades 6-8) students (n = 5,423) are analyzed for ethnic differences in major depression. The point prevalence of major depression was 8.4% without and 4.3% with impairment. Data were sufficient to calculate prevalences for nine ethnic groups. Prevalences adjusted for impairment ranged from 1.9% for youths of Chinese descent to 6.6% for those of Mexican decent. African and Mexican American youths had significantly higher crude rates of depression without impairment, but only the latter had significantly higher rates of depression with impairment. Multivariate (logistic regression) analyses, adjusting for the effects of age, gender, and socioeconomic status (SES), yielded significant odds ratios for only one group. Mexican American youths were at elevated risk for both depression without (OR = 1.74, p < .05) and depression with impairment (OR = 1.71, p < .05). There was no significant interaction of ethnicity and SES in relation to depression. Females had higher prevalences of depression with and without impairment, as did youths who reported that their SES was somewhat or much worse off than their peers. The data add to growing evidence that Mexican American youths are at increased risk of depression, and that community intervention efforts should specifically target this high-risk group.

Adolescent↗
PubMed1997

Treatment of frontal sinus osteoma using a craniofacial approach.

Osteoma is one of most common benign tumors of the nose and paranasal sinuses, with the frontal sinus being its most frequent location. It may be locally destructive and aggressive with possible intracranial complications. Osteoma of the frontal sinus comprises 57% of all osteomas in the paranasal sinuses. In 1939, Childrey reviewed 3,510 consecutive sinus radiographs taken for any reason and found an incidence of 0.43% of paranasal sinus osteomas. There are many operative approaches for frontal sinus osteomas, such as external frontoethmoidal approach and osteoplastic frontal sinusectomy, both with high recurrence rates. Those traditional operative methods cannot radically eradiate the osteoma grown in the posterior table of the frontal sinus. From July 1991 to June 1992, three patients with symptomatic frontal sinus osteomas were operated by a craniofacial approach. One patient is presented here in detail. A coronal incision is used and is found to be beneficial both in surgical exposure and in reconstruction with a calvarial bone graft. The patient has been followed for 3.5 years without osteoma recurrence.

Bone Neoplasms↗