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Biomedical subjects

D P Lin

Publications and source records attributed to D P Lin.

8 recordsLinked to original sources

Mouse models for human familial adenomatous polyposis.

Colorectal cancer (CRC) is the second most frequent type of cancer in the Western hemisphere. In the United States alone, it is estimated that 150 000 new cases are detected every year and more than 65 000 patients die from complications associated with this cancer. Identification of genes implicated in the initiation and progression of colorectal cancer in humans has prompted the generation of mouse models for this cancer. We will provide a brief overview of these mouse models for CRC and what they have contributed to our understanding of the events involved in the initiation and progression of this cancer.

Adenomatous Polyposis Coli↗

Fission yeast Slp1: an effector of the Mad2-dependent spindle checkpoint.

Mad2 is a component of the spindle checkpoint, which delays the onset of anaphase until all chromosomes are attached to the spindle. Mad2 formed a complex with Slp1, a WD (tryptophan-aspartic acid)-repeat protein essential for the onset of anaphase. When the physical interaction between the two proteins was disrupted, the spindle checkpoint was no longer functional. Post-anaphase events such as chromosome decondensation and the next round of DNA replication were not delayed even when the spindle assembly was incomplete. This relief of dependence appears to be a result of deregulation of ubiquitin-dependent proteolysis mediated by the anaphase-promoting complex.

Anaphase↗

[Pulmonary resection by dealing with pulmonary vessels inside pericardium: report of 104 cases].

During 1985-1993, the writer had performed 104 pulmonary resections, which was 10% of the same time pulmonary resections, to treat type III center lung carcinoma by dealing with pulmonary vessels inside pericardium. The results demonstrated: one-year survival rate was 35%, while three year survival rate was 10%. The writer also found that this kind of operative mode can raise the pulmonary resection rate by 8.75%, and reduce the exploratory thoracotomy rate by 33% compared with the traditionary pulmonary resection.

Adenocarcinoma↗

[Research of the electrophysiological properties of isolated ventricular papillary muscle of rhesus].

The electrophysiological properties of cardiac muscle of rhesus (Macaca mulatta) by use of intracellular electrode technique has been described in this paper. Thirty papillary muscle from 8 rhesus were used for this research and 68 successful records had been obtained. The value of resting potential is -86.26 +/- 7.57 mV (M +/- SD). The configuration of the action potential is typical for the ventricular muscle of mammalian. The amplitude of action potential is 118.80 +/- 10.69 mV: over-shoot is 25.57 +/- 6.11mV. The APD20, APD50, APD80, APD100 is 184.33 +/- 64.04, 301.02 +/- 95.32, 382.17 +/- 125.81 and 436.33 +/- 122.39 ms, respectively. The maximum depolarization velocity of 0 phase is 101.20 +/- 17.59 V/s. The effective refractory period is 292.69 +/- 93.91ms. Comparing the results of the rhesus cardiac muscle with that of other mammalians, authors found that they were very similar. It is suggested that the results and analysis of its mechanism derived from investigation of other mammalian cardiac tissues are applicable to the human.

Action Potentials↗

Identification of ventricular tachycardia using intracavitary ventricular electrograms: analysis of time and frequency domain patterns.

Tachycardia detection by implantable antitachycardia devices using rate alone has major limitations. Several alternative methods have been proposed to distinguish ventricular tachycardia or ventricular fibrillation from normal sinus rhythm using intracardiac electrograms. These methods have not been tested, however, for recognition of ventricular tachycardia in patients with abnormal surface QRS conduction during sinus rhythm or with antiarrhythmic drug therapy. In this study, three techniques for the identification of ventricular tachycardia from intracavitary bipolar ventricular electrograms were examined and compared: correlation waveform analysis, amplitude distribution analysis, and spectral analysis using Fast Fourier transformation. Thirty episodes of induced monomorphic ventricular tachycardia were analyzed and compared sinus rhythm in four groups of patients with: I. Normal surface QRS conduction during sinus rhythm without antiarrhythmic drug therapy (five episodes); II. Intraventricular conduction delay or bundle branch block during sinus rhythm without antiarrhythmic drug therapy (nine episodes); III. Normal surface QRS conduction during sinus rhythm with antiarrhythmic therapy (six episodes); and IV. Intraventricular conduction delay or bundle branch block during sinus rhythm with antiarrhythmic drug therapy (ten episodes). Correlation waveform analysis had 100% sensitivity and specificity in distinguishing ventricular tachycardia from sinus rhythm, even in the presence of an intraventricular conduction delay, bundle branch block, and antiarrhythmic drug therapy. In contrast, amplitude distribution analysis differentiated 15/30 episodes (50.0%) of ventricular tachycardia from sinus rhythm, and a maximum of 18/30 episodes (60.0%) of ventricular tachycardia were identified by special analysis using Fast Fourier transformation. Correlation waveform analysis appears to be a reliable technique to discriminate ventricular tachycardia from sinus rhythm using intracavitary ventricular electrograms. Its computational demands are modest, making it suitable for consideration in an implantable antitachycardia device.

Adolescent↗

Mutagenicity of the anticancer drug, caracemide, and related compounds for salmonella.

Caracemide, MeCON(CONHMe)(OCONHMe) (I), is a novel anticancer drug. Since it was derived from acetohydroxamic acid (II), a known mutagen, its potential metabolites and related compounds were synthesized and tested for mutagenicities in S. typhimurium TA98 and TA100. These compounds were: MeNHCONH(OCONHMe) (III), MeCONH(OCONHMe) (IV), MeCONOH(CONHMe) (V), MeNHCOONH2 X HCl (VI), MeNHCONHOH (VII), MeNHCOON(CONHMe)2 (VIII), and NOH(CONHMe)2 (IX). The mutagenicities in the absence of rat liver homogenate were: (VI) much greater than (IV) greater than (II), (III), (V). The other compounds were not mutagenic. (I) was mutagenic only in the presence of rat liver homogenate. The doses required to demonstrate mutagenicities of these compounds were from 0.05 to 5 mumoles/plate. The major hydrolytic products at 25 degrees C, pH 7, were (III), (IV), and (V) from (I); (II) and (III) from (IV); and (II), (III), (VII) and MeNHCONH(OCOMe) (X) from (V). (III) was stable at pH 7. Treatment of (IV) with HCl yielded (VI). Hydrolysis of (III) or (V) with ammonia yielded (VII). These results suggest that caracemide may be activated enzymatically or nonenzymatically by deacetylation or decarbamoylation, and its anticancer activity may be related to the reactivity of its metabolites with DNA. The synthetic procedures and characterizations of new compounds (IV), (V) and (X) are described.

Animals↗

Enterococcus faecalis endocarditis presenting as meningitis.

Although Enterococcus faecalis is a relatively common cause of infective endocarditis, it rarely causes meningitis. A case of Enterococcus faecalis endocarditis presenting as meningitis in a 74-year-old diabetic man on chronic hemodialysis is reported. A review of the literature showed that the association of enterococcal meningitis and endocarditis has rarely been reported. This clinical association may be more common than previously recognized and it is suggested that echocardiography be considered for all patients with enterococcal hematogenous meningitis in order to rule out endocarditis.

Endocarditis, Bacterial↗