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Biomedical subjects

F M Lin

Publications and source records attributed to F M Lin.

At least 19 recordsLinked to original sources
PubMed2003

Database of repetitive elements in complete genomes and data mining using transcription factor binding sites.

Approximately 43% of the human genome is occupied by repetitive elements. Even more, around 51% of the rice genome is occupied by repetitive elements. The analysis presented here indicates that repetitive elements in complete genomes may have been very important in the evolutionary genomics. In this study, a database, called the Repeat Sequence Database, is first designed and implemented to store complete and comprehensive repetitive sequences. See http://rsdb.csie.ncu.edu.tw for more information. The database contains direct, inverted and palindromic repetitive sequences, and each repetitive sequence has a variable length ranging from seven to many hundred nucleotides. The repetitive sequences in the database are explored using a mathematical algorithm to mine rules on how combinations of individual binding sites are distributed among repetitive sequences in the database. Combinations of transcription factor binding sites in the repetitive sequences are obtained and then data mining techniques are applied to mine association rules from these combinations. The discovered associations are further pruned to remove insignificant associations and obtain a set of associations. The mined association rules facilitate efforts to identify gene classes regulated by similar mechanisms and accurately predict regulatory elements. Experiments are performed on several genomes including C. elegans, human chromosome 22, and yeast.

Algorithms↗
PubMed2003

High-level expression of ampC beta-lactamase due to insertion of nucleotides between -10 and -35 promoter sequences in Escherichia coli clinical isolates: cases not responsive to extended-spectrum-cephalosporin treatment.

Two Escherichia coli isolates were recovered from the blood of two cancer patients and were demonstrated to produce high levels of the AmpC beta-lactamase with isoelectric points of >9.0. The hypertranscription of ampC RNA was observed by Northern blot hybridization in both isolates. One isolate (isolate EC44) had a point mutation (G-->A at position -28) and insertion of thymidine between positions -20 and -19 of the ampC promoter gene (GenBank accession no. AE000487). The single nucleotide insertion of T between positions -19 and -20 created an optimal distance (17 bp) in the Pribnow box for ampC hyperproduction. The other isolate (isolate EC38) had two point mutations (G-->A at position -28 and C-->T at position +58) and a 2-base (GT) insertion between positions -14 and -15. Although the insertion of GT between positions -14 and -15 may create a new promoter next to the original promoter, cloning of the ampC region with truncated nucleotides of the original -35 region of EC38 failed to verify the hypothesis that a new promoter would be created by such a nucleotide insertion. Instead, multiple start sites for ampC transcription at -1, +1, +2, and +3 were observed in an S1 nuclease protection assay. These results suggest that the RNA polymerase is flexible in the selection of a start site in ampC hypertranscription. In conclusion, nucleotide insertions between the -35 and -10 ampC promoter sequences was the mechanism for the hyperproduction of AmpC beta-lactamase and resistance to oxyimino-cephalosporins. The failure of the two patients to respond to treatment with oxyimino-cephalosporins highlights the important role of such a resistance mechanism in the clinical setting.

Bacterial Proteins↗
PubMed2001

Outer membrane protein change combined with co-existing TEM-1 and SHV-1 beta-lactamases lead to false identification of ESBL-producing Klebsiella pneumoniae.

Nine isolates of Klebsiella pneumoniae, obtained from one colonized and eight bacteraemic patients on a paediatric ward, were shown to be identical by PFGE, indicating an outbreak. Screening for extended-spectrum beta-lactamase (ESBL) production using the double-disc synergy test, Etest for ESBLs and agar diffusion tests indicated ESBL production. The isolates showed reduced susceptibility to cefotaxime but not to other third-generation cephalosporins. Molecular studies revealed production of TEM-1 and SHV-1 but no ESBLs were identified. Deficiency in expression of an outer membrane protein (OmpK35) was also observed. These observations led us to postulate that the extremely low level of OmpK35 expression and the co-existence of TEM-1 and SHV-1 resulted in an increased MIC of cefotaxime and the false designation of the isolates as ESBL producers. All the infected infants were treated with either third-generation cephalosporins alone or multiple antibiotics including a third-generation cephalosporin, and recovered and were discharged without sequelae.

Anti-Bacterial Agents↗
PubMed2001

Use of automated riboprinter and pulsed-field gel electrophoresis for epidemiological studies of invasive Haemophilus influenzae in Taiwan.

A total of 87 invasive isolates of Haemophilus influenzae isolated throughout Taiwan from 1994 to 1998 was collected; 57 were from children <14 years old. In all, 60.9% of isolates were resistant to ampicillin and produced beta-lactamase. Ribotyping revealed six different profiles in 55 isolates of type b, nine profiles in 10 isolates of non-type b and 12 profiles in 22 isolates of non-typable H. influenzae. Among isolates from 35 cases of meningitis, 30 (86%) were in ribogroups 1, 2 and 3 with >90% genetic similarity. Compared with all the other ribogroups, ribogroups 1, 2 and 3, which encompassed all H. influenzae type b, were significantly more prevalent as a cause of meningitis in children <14 years old. Further subtyping of the predominant ribogroup by pulsed-field gel electrophoresis (PFGE) identified differences of 0-6 bands among these isolates of ribogroup 1, which indicated distant relatedness. Automated ribotyping was found to be a useful method and was less time-consuming for molecular epidemiology studies of H. influenzae. PFGE is suggested as an addition to ribotyping to improve discrimination if H. influenzae type b is involved. Differentiating ribogroups between type b and non-type b H. influenzae by genotyping may help to understand the molecular characteristics of outbreaks, endemicity and value of vaccination. According to the results of ribotyping and PFGE, it seems possible that spread of invasive H. influenzae type b had occurred and ribotyping confirmed that there was no clonal spread of non-type b H. influenzae in Taiwan.

Adult↗
PubMed1999

Bacteremia due to extended-spectrum beta-lactamase-producing Escherichia coli and Klebsiella pneumoniae in a pediatric oncology ward: clinical features and identification of different plasmids carrying both SHV-5 and TEM-1 genes.

Thirteen patients who had 16 episodes of bacteremia were observed between 1993 and 1997 in a pediatric oncology ward with a high background isolation rate of cefotaxime- or aztreonam-resistant gram-negative bacteria. Four blood isolates were Escherichia coli and 12 were Klebsiella pneumoniae, and these isolates harbored extended-spectrum beta-lactamases (ESBLs). All episodes of bacteremia were nosocomial, all except one of the episodes occurred in neutropenic patients, and all patients were treated with piperacillin or ceftazidime with amikacin and cefazolin prior to the onset of bacteremia. Nine of 13 patients were receiving extended-spectrum beta-lactam treatment when the bacteremias caused by ESBL producers occurred. Molecular studies revealed that four K. pneumoniae SHV-2-producing isolates from 1994 were of the same clone. Other ESBL producers, including six that carried both TEM-1 and SHV-5, five that carried SHV-5, and one that carried SHV-2 alone, were unrelated. In conclusion, SHV-5 was present in 11 of the 16 isolates and coexisted with TEM-1 in 6 isolates. Acquisition of resistance genes probably occurred under antibiotic selection pressure. This study highlights the importance of routine checks for and detection of ESBL producers. Effective therapy against ESBL producers should be considered early for children who have malignancies and neutropenia and who are septic, despite treatment with a regimen that includes an extended-spectrum beta-lactam, in a clinical setting of an increased incidence of ESBL-producing bacteria.

Adolescent↗
PubMed1999

Correlation of spasticity with hyperactive stretch reflexes and motor dysfunction in hemiplegia.

OBJECTIVES: To study the correlation between spasticity and motor dysfunction in the wrist-hand unit of adult hemiplegic patients, and to investigate the correlation between clinical spasticity and hyperactive stretch reflexes. STUDY DESIGN: A survey study with a sequential case series of subjects. SETTING: Neuromuscular Research Laboratory, School of Physical Therapy, Texas Woman's University, Houston, TX. SUBJECTS: Sequential sample recruited from local stroke support groups: 10 patients with chronic hemiplegia caused by cerebral vascular accident who had various degrees of spasticity in the wrist joint. OUTCOME MEASURES: Modified Ashworth Scale, amplitudes of stretch reflexes for wrist flexors, grip strength, active range of motion of the wrist joint, and Fugl-Meyer test. RESULTS: Strong reverse correlation was found between spasticity and grip strength, the Fugl-Meyer test scores, and the Box and Blocks test scores (p = .001 to .005). Results also indicated a strong and consistent correlation between spasticity and reflexive electromyographic activities of the stretch reflex recorded from active muscles (p = .005 and .007), but not between spasticity and torque response of the stretch reflex. CONCLUSIONS: The degree of wrist spasticity is associated with impaired hand function in hemiplegic patients, and hyperactive electromyographic response of the stretch reflex, recorded from active muscles, is a valid indicator of spasticity.

Aged↗
PubMed1998

The aging effects on the EMG and mechanical responses of the human wrist flexor stretch reflexes.

The purpose of this study is to investigate the effects of aging on the human stretch reflexes. The EMG and torque responses of the stretch reflex of the wrist flexors were evoked by ramp-and-hold mechanical perturbations. The stretch reflexes were recorded at seven test conditions with different stretch velocity and muscle preload. The test results from young and older healthy adult subjects were compared. In average, the absolute amplitude of the short-latency (20-40 ms) EMG (recorded from flexor carpi radialis) reflex response was significantly lower in the older group. If the data were normalized and expressed in percentage of the maximal voluntary EMG activity, however, this group difference was not significant. There was no change in the reflex gain of the short-latency reflex with aging. For the long-latency (50-90 ms) EMG reflex response, both the normalized amplitude and the reflex gain were significantly enhanced with aging, probably through supraspinal mechanisms. There was no significant difference in the threshold velocity for the evoked EMG reflexive activities between age groups. There were also no changes in the reflexive wrist flexion torque with aging. These results suggested that the number of motor units recruited during the stretch reflex activity declined with aging although the percentage of motor units recruited was not affected by aging. It is concluded that the central regulating mechanisms of the spinal motoneuron excitability are not compromised by aging. The automatic gain compensation phenomenon is also preserved with aging.

Adult↗
PubMed1997

Functional assessment of tibial-nerve recovery in the cat using gait analysis: preliminary study.

The purpose of this study was to investigate gait-pattern changes after complete tibial nerve lesion in the cat, and to observe whether nerve repair could reverse some of the changes. In six cats, a 5-cm segment of the tibial nerve was transected. The nerve gap was then repaired with nerve autograft in three animals and was unrepaired in three as controls. The walking patterns of the cats were videotaped, and the hip, knee, ankle, and metatarsophalangeal joint angles were measured at the beginnings of the F, E1, E2, and E3 phases of the step cycle. Two weeks after surgery, abnormal gait patterns were observed, and four gait parameters (E3.Hip, E3.Ankle, E3.M-P, and F.Ankle) were found to be statistically significantly different from normal. Six months after surgery, the nerve-graft group had gait-parameter values approaching normal, while the control group showed no measurable improvement. Correspondingly, electrophysiologic testing revealed considerable nerve regeneration in the nerve-graft group but not in the control group. It was concluded that these gait parameters can be used as valid functional indices to evaluate the degree of tibial nerve recovery in the cat model.

Action Potentials↗
PubMed1997

Expression of DNA topoisomerase II alpha and multidrug resistance p-glycoprotein in acute leukemia.

BACKGROUND: Drug resistance is a major cause of treatment failure in acute leukemia. Overexpression of multidrug resistance gene and decreased activity of topoisomerase II alpha are suggested as two important mechanisms for this resistance. METHODS: We used immunohistochemical method to determine the expressions of both topoisomerase II alpha (topo II alpha) and p-glycoprotein (gp-170) in bone marrow biopsy specimens from 68 cases of acute leukemia. Patients were divided into four groups: (1) leukemia cells with high score for topo II alpha and negative for gp-170; (2) leukemia cells with high score for topo II alpha and positive for gp-170; (3) leukemia cells with low score for topo II alpha and negative for gp-170; and (4) leukemia cells with low score for topo II alpha and positive for gp-170. The clinical responses were then followed as routine, and the clinical correlation was evaluated by analysis of variance and Pearson Chi-Square test. RESULTS: The measure of the single parameter (either topo II alpha or gp-170 alone) did not show a significant difference in the overall survival. However, the complete response rate was much higher in the first group patients whose bone marrow reading score was high in topo II alpha and negative for gp-170 expression. Survival duration increased with the increase in the complete response rate. CONCLUSIONS: Combined parameters of topo II alpha and gp-170 are more useful than any individual parameter for the prognosis of acute leukemia.

ATP Binding Cassette Transporter, Subfamily B, Mem↗
PubMed1996

Ankle stance angle: a functional index for the evaluation of sciatic nerve recovery after complete transection.

This study attempted to develop a motor functional index, ankle stance angle (ASA), to assess rat sciatic nerve regeneration subsequent to autografting. ASA, 50 degrees in normal rats, is the ankle joint angle at the mid-stance phase of the gait cycle. In a nerve graft group, a 1-cm segment of the right sciatic nerve was transected and then repaired with nerve autograft. In an ungrafted group, the nerve gap was left unrepaired. ASA measured 4 months after surgery was statistically significantly larger in the nerve graft group (36 degrees) than in the ungrafted group (22 degrees). The results suggest that ASA is more sensitive than sciatic function index in detecting functional recovery after a complete sciatic nerve lesion. ASA also showed a significant correlation with the passive range of ankle joint motion and gastrocnemius muscle weight. The study concluded that ASA is a reliable index for assessment of regeneration of rat sciatic nerve after a complete lesion. The intra-rater reliability (r = 0.97 and 0.90) and inter-rater reliability (r = 0.85) tests performed support the conclusions.

Animals↗
PubMed1995

A quality study of a computerized medical birth registry.

Processed by a computerized medical birth registry system, the birth records of 20,103 deliveries, from February 1992 to February 1993, were digitized with medium registry. From January 1, to February 28, 1993, the original records (n = 2,840 cases) of all 10 collaborative hospitals were requested for assessment of the data quality. Thirty-six items were scored, data of poor quality was found in 8 items; acceptable quality in 4 items; and good quality in 28 items. The feasibility of data transfer by floppy disc and per modem was evaluated. This registry system had shortened data processing time effectively and improved mutual feedback between data center and delivery units. Errors resulting from technical faults originating in preparation of the data for computerizing at hospital level could be effectively reduced. The validity of diagnosis remained as the major source of errors.

Birth Certificates↗
PubMed1995

Induction of megakaryocytic differentiation in a newly established human leukemic cell line by 12-o-tetradecanoylphorbol-13-acetate.

BACKGROUND: Biological studies on megakaryopoiesis have been hampered by the scarcity of megakaryocytes in normal bone marrow and difficulty in long term culture. Alternatively, leukemic cell lines with megakaryocytic differentiation potential may provide good models to counter these problems. METHODS: Leukemic cells from a patient with acute megakaryocytic leukemia were put into long-term culture and established into a cell line which was designated as VGH-MK1. The VGH-MK1 cells were challenged with differentiation agents and/or cytokines, and the differentiation of these cells was examined using morphological, immunocytochemical and surface-marker studies. RESULTS: Morphologically, VGH-MK1 cells had prominent nucleoli and basophilic cytoplasm with some protrusions, but large cells were occasionally seen. Under regular culture condition, the cells had a doubling time of 36-48 hours. The cloned cell line exhibited markers characteristic of megakaryoblasts after differentiation induction. Specifically, when stimulated with 12-o-tetradecanoylphorbol-13-acetate (TPA), cells became larger and had large or multinuclei. They were induced to express platelet glycoproteins GPIb (CD42b), GPIIb/IIIa (CD41), and GPIIIa (CD61) antigens, but not erythroid nor lymphoid markers. Platelet peroxidase (PPO) activity was also induced. Retinoic acid did not exhibit similar differentiation-inducing effects. In contrast, it counteracted the effects induced by TPA. CONCLUSIONS: An unique human leukemic cell line, VGH-MK1, has been established here. It could be induced to exhibit some characteristics of megakaryocytic lineage, and may be an useful model for the biological studies of megakaryopoiesis.

Adult↗
PubMed1994

Do the reticulocyte maturation fractions and bone marrow reticulocyte count further help the classification of anemias?

BACKGROUND: Reticulocyte count plays a major role in anemic evaluation. The conventional method done by the manual supravital staining cannot subclassify the group of less than 2% of corrected reticulocyte count. The newly-developed flow cytometer provides different maturation fractions by measuring its fluorescent intensity. The reticulocytes are believed to shift to the circulation from the bone marrow earlier in more severe anemia. Therefore, the purpose of this study is to evaluate the role of reticulocyte maturation fractions and bone marrow reticulocyte in anemia classification. METHODS: By using a fully automated counter, the roles of the reticulocyte with maturation and their shifting from bone marrow were evaluated in anemias. Different groups of subjects (243 in total) including aplastic, nutritional, and infiltrative anemias and anemia due to excess destruction and blood loss were studied. Each subject had bone marrow examination for morphologic diagnosis and reticulocyte evaluation. RESULTS: Both the absolute count and the maturation fractions of reticulocytes showed significant difference among marrow infiltration, aplastic anemia, and hemolytic anemia. Both the absolute reticulocyte count and less mature fractions were lowest in aplastic group. The marrow reticulocyte counts and shift ratio to circulating blood added little benefit in the classification of anemias. CONCLUSIONS: The automated reticulocyte count with maturation fractions helps classify anemias, particularly for those with low reticulocyte count by the manual method.

Adolescent↗
PubMed1991

Detection of 20-hydroxyeicosatetraenoic acid in rat urine.

20-Hydroxyeicosatetraenoic acid (20-HETE), an arachidonate metabolite of the cytochrome P450 omega hydroxylase, was detected in rat urine by gas chromatography-mass spectrometric techniques. The concentration of 20-HETE in urine from 7-week-old hypertensive and normotensive rats was 2.1 and 1.3 nM, respectively. This is the first demonstration of 20-HETE urinary excretion and thus calls attention to the possibility that 20-HETE participates in the regulation of renal function via its effect on vascular tone and ion transport processes.

Animals↗
PubMed1991

Effect of stabilization temperature on the degradation of adriamycin in albumin microspheres.

The effect of stabilization temperature on the degradation of adriamycin HCl during the preparation of albumin microspheres was investigated. The degradation of adriamycin HCl by heating at various temperature with different time interval in dried adriamycin HCl powder, adriamycin HCl aqueous solution, wetted Adriablastina (adriamycin HCl with lactose) powder and Adriablastina aqueous solution was also studied. In the presence of water the degradation of adriamycin HCl was found; whereas, in the absence of water no degradation occurred. The degradation of adriamycin HCl in solution and wetted powder showed a zero order reaction. An increase in temperature increased degradation rate. The rate constant for adriamycin HCl degradation in Adriablastina solution obtained was in good agreement with that in adriamycin HCl solution. It was suggested that the presence of lactose had no interference in the degradation of adriamycin HCl. The zero-order reaction of degradation was attributed to the drug behaved like a suspension. The degradation of adriamycin HCl at various stabilization temperature during the preparation of microspheres had the same tendency as those of the adriamycin HCl solution and the wetted adriamycin HCl powder that were heated by the DSC instrument with the condition similar to the preparation of microspheres.

Doxorubicin↗