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Biomedical subjects

S L Lin

Publications and source records attributed to S L Lin.

At least 145 records · Page 8Linked to original sources
PubMed1989

Ultrasonic tissue characterization of acute canine myocardial infarction.

This study assessed changes in left ventricular texture on two-dimensional (2-D) echocardiography after experimental myocardial infarction. In 13 dogs, the left anterior descending coronary artery (LAD) was occluded for 3 h, followed by 1 h of reperfusion and sacrifice. Two-dimensional echocardiography was performed pre-LAD occlusion, 3 h post occlusion and 1 h after reperfusion by placing a 5 MHz transducer on the chest wall. After sacrifice, triphenyltetrazolium chloride staining was performed on 1 cm thick left ventricular cross-sectional slices. Five dogs served as controls (shams). Two-dimensional echocardiograms were digitized and in the region of left ventricular asynergy (area of myocardial infarction), and adjacent normal area, the mean pixel intensities (+/- SD) were calculated. There was no significant change in the mean pixel intensity from 0 through 4 h in the lateral (22.8 +/- 1.3 and 23.4 +/- 1.8) and anteroseptal (23.2 +/- 1.9 and 22.6 +/- 1.9) regions in sham operated dogs. In dogs undergoing LAD occlusion, the mean pixel intensity from the pre- to post occlusion period showed no significant change in the lateral (normal) area, 24.4 +/- 2.7 versus 24.7 +/- 2.9. In the area of wall motion abnormality (area of myocardial infarction) the mean pixel intensity increased from 25.4 +/- 2.7 to 33.7 +/- 4.5, P less than 0.01. There was no significant change in the mean pixel intensity between the 3 h post occlusion and post reperfusion period in either the lateral (normal) or anteroseptal areas of the left ventricle. The area of left ventricular asynergy corresponded to the area of myocardial infarction on triphenyltetrazolium chloride stain.(ABSTRACT TRUNCATED AT 250 WORDS)

Acute Disease↗
PubMed1989

Platelet activation in patients with mitral valve prolapse.

An increased frequency of thromboembolic events in patients with mitral valve prolapse has been demonstrated. It has been suggested that this association may be related to increased systemic platelet activity. Beta-thromboglobulin (BTG) is a platelet specific protein secreted during the platelet release reaction, with BTG levels reflecting ongoing platelet activation. Plasma BTG levels were measured in 14 normal volunteers, 23 patients with mitral valve prolapse and nonthickened mitral leaflets (group 1) and 13 patients with mitral valve prolapse and thickened mitral leaflets (group 2). The BTG level was 8.1 +/- 4.6 ng/mL (mean +/- SD) in normal subjects, 9.6 +/- 5.5 ng/mL in the nonthickened mitral valve prolapse group and 10.0 +/- 5.7 ng/mL in thickened mitral valve prolapse group. There was no significant difference in the BTG levels between groups. Five patients with multiple valvular prolapse did not show elevation of BTG levels. The present study did not demonstrate increased BTG levels in neurologically asymptomatic mitral valve prolapse patients.

Adult↗
PubMed1989

Minimal requirement of effective dilation diameter of balloon(s) in percutaneous transluminal mitral valvotomy.

40 patients are included to study the minimal requirement of effective dilation diameter of balloon(s) in performing percutaneous transluminal mitral valvotomy (PTMV) to obtain good hemodynamic and long-term follow-up consequences. The patients are divided into 2 groups depending on the ratio of effective dilation diameter of balloon(s) (determined by calculating the cross-sectional area of the oval enveloping the one or two balloons and then taking the diameter of the circle with the same area) to mitral annular diameter (determined by 2-dimensional echocardiography) (Balloon-Mitral Anular Ratio, BMAR). BMAR in group 1 may be equal to or greater than 0.80 or 0.90, BMAR in group 2 may be less than 0.80 or 0.90. From the careful analysis, the statistically significant immediate hemodynamic improvement, e.g. the reduction of trans-valvular pressure gradient, left atrial pressure, pulmonary artery systolic pressure, the increase of mitral valve area, can be obtained even BMAR is less than 0.80. However, the increase of stroke volume index after PTMV can only be obtained with the BMAR equal to or greater than 0.80. The long-term improvement, determined by greater increment of exercise duration, is also only obtained if the BMAR equal to or greater than 0.80 at PTMV. Therefore, we conclude that to obtain the adequate and satisfactory immediate hemodynamic and long-term follow-up results of PTMV, the BMAR must exceed 0.80.

Adult↗
PubMed1989

Acute primidone intoxication: report of a case.

A case of acute primidone intoxication, due to overdose, was evaluated at National Taiwan University Hospital. Serial assessment of the clinical manifestations, electroencephalograms and serum levels of primidone and phenobarbital were made. From these data, we conclude that the toxic effects, such as depression of the central nervous system and dysequilibrium, are due mostly to primidone itself, rather than its metabolite, phenobarbital.

Adult↗
PubMed1989

[Determination of berberine in Angong Niuhuang Wan by HPLC].

A normal phase liquid chromatographic method was developed for the determination of berberine-type alkaloids in rhizoma Coptidis and traditional Chinese medicine--Angong Niuhuang Wan. Experimental evidences indicate that a normal phase system of a silica column (3.9 x 250 mm) as stationary phase with an eluent of ethyl acetate-formic acid-ethanol (15:3:2) as mobile phase can separate excellently (R5 greater than 1.5) four berberine-type alkaloids in the samples tested. According to the results obtained with this method the percent content of berberine hydrochloride in some Angong Niuhuang Wan from different factories and different batches was 0.331-0.456% and the average recovery was 97.23%; coefficient of variation was 1.2%.

Berberine↗
PubMed1989

[Determination of berberine and palmatine in cortex phellodendron and Chinese patent medicines by HPLC].

Berberine (1) and palmatine (2) in cortex phellodendron and Chinese patent medicines were determined by HPLC. The optimal composition of mobile phase CH3COOEt-HCOOH-EtOH (15:3:2) for HPLC separation of berberine and palmatine was successfully determined by using window diagram technique. Detection wavelength was 346nm. Flow rate: 1.5 ml/min. Calibration graphs for 1 and 2 were rectilinear for 0.06-0.32 micrograms and 0.12-0.32 micrograms respectively. The average recoveries of the two corresponding components were found to be over 96% and their coefficients of variation were below 5%.

Berberine↗
PubMed1988

Comparison of Doppler echocardiographic and hemodynamic indexes of left ventricular diastolic properties in coronary artery disease.

Transmitral flow velocity was measured by Doppler echocardiography in 15 patients with coronary artery disease simultaneously with high-fidelity recording of left ventricular pressure. Doppler echocardiographic recordings were also performed in 14 age- and heart rate-matched normal subjects. Statistically significant differences (p less than 0.05) in acceleration half-time (55.3 +/- 8.2 vs 70.4 +/- 14.9 ms), deceleration half-time (83.1 +/- 17.9 vs 109.5 +/- 18.1 ms), deceleration rate (4.9 +/- 0.9 vs 3.1 +/- 0.9 m/s2), peak velocity of early diastolic left ventricular inflow (E wave) (0.78 +/- 0.13 vs 0.61 +/- 0.13 m/s) and A/E ratio (0.74 +/- 0.20 vs 0.98 +/- 0.31) between normal subjects and patients were noted. There was no significant difference in peak velocity of atrial systolic flow (A wave) between normal subjects and patients. Correlation between transmitral flow indexes and hemodynamic indexes of left ventricular diastolic properties were poor, with r values ranging from 0.02 to 0.65. Significant correlations between deceleration rate versus maximal isovolumic left ventricular pressure decrease (maximum -dP/dt) and A wave versus maximum -dP/dt (p less than 0.05) were found (0.53 and 0.65, respectively). Deceleration rate was the most sensitive index of isovolumic relaxation assessed by hemodynamic methods, whereas the A/E ratio was a poor indicator of hemodynamic measurements of isovolumic relaxation. An abnormal deceleration rate had 100% specificity for detecting abnormal maximum -dP/dt, while abnormal acceleration half-time, deceleration half-time and A/E ratio had 80% specificity for detecting abnormal time constant. The deceleration rate, acceleration half-time, deceleration half-time and A/E ratio had a predictive value of 60 to 100% for the detection of abnormal maximum -dP/dt and time constant.

Adult↗
PubMed1988

Orientation of carbon monoxide and structure-function relationship in carbonmonoxymyoglobin.

Fourier transform infrared spectroscopy of the CO stretch bands in carbonmonoxymyoglobin (MbCO) reveals three major bands implying that MbCO exists in three major substates, A0, A1, and A3. After photolysis at low temperatures the CO is in the heme pocket, and the resulting CO stretch bands represent the B substates. Photoselection experiments determine the orientation of CO in the A (bound) and B (photolyzed) substates: Small fractions of MbCO are photolyzed at 10 K with linearly polarized light at 540 nm. The resulting linear dichroism in the A and B IR bands yields the tilt angle between the heme normal and CO. The average angles are as follows: alpha (A0) = 15 degrees +/- 3 degrees; alpha (A1) = 28 degrees +/- 2 degrees, and alpha (A3) = 33 degrees +/- 4 degrees. The A bands are inhomogeneously broadened; the angle alpha shows a wavenumber dependence within the A bands. The wavenumber dependence is interpreted as a distribution of the tilt angle within the individually inhomogeneous A substates, thus providing a structural parameter to characterize the distribution of the conformational substates. The B substates exhibit no induced linear dichroism; in the photolyzed substates the ligand is randomly oriented with respect to the heme plane. The present results together with earlier data on static and kinetic properties of CO binding to Mb establish relations among spectroscopic, structural, energetic, and functional parameters.

Carbon Monoxide↗
PubMed1988

Promotion of Mycoplasma pulmonis growth in rat tracheal organ cultures by ammonium chloride.

During exacerbation of respiratory mycoplasmosis in rats by environmental ammonia, numbers of Mycoplasma pulmonis organisms in the respiratory tract are increased. To test whether or not exposure of respiratory epithelium to ammonia in vitro promotes growth of the organism, rat tracheal organ cultures were treated with 50 mM ammonium chloride, inoculated with M. pulmonis, and quantitatively cultured. After 48 hours, treated tracheas harbored almost 10 times more M. pulmonis colony-forming units than control tracheas. Cellular lesions in the epithelium of treated tracheas resembled those in the nasal passages of rats exposed to gaseous ammonia. To determine whether or not growth-modifying factors were released from tracheal epithelium exposed to ammonium chloride, M. pulmonis growth was assessed in medium collected from ammonium chloride-treated and control tracheas. Growth in medium from treated tracheas was greater than that in medium from untreated tracheas.

Ammonium Chloride↗
PubMed1987

Deprotonation of tyrosines in bacteriorhodopsin as studied by Fourier transform infrared spectroscopy with deuterium and nitrate labeling.

Fourier transform infrared (FTIR) difference spectra are presented for bacteriorhodopsin (BR) at low temperature. Previous FTIR measurements have identified several tyrosine residues that change their absorption characteristics between light-adapted BR and dark-adapted BR, or between intermediates K and M [Dollinger, G., Eisenstein, L., Lin, S.-L., Nakanishi, K., Odashima, K., & Termini, J. (1986) Methods Enzymol. 127, 649-662]. These changes were explained by protonation/deprotonation of tyrosine moieties and perturbation of the protein environment surrounding tyrosines. A tyrosine deprotonation was observed to occur between intermediates K and M. The present studies confine the deprotonation to being between intermediates L and M and show that no tyrosines undergo changes between the K and the L states. Evidence is presented that none of the tyrosines undergoing changes at low temperature can be assigned to tyrosine-64. The environmental changes of these tyrosines are discussed in relation to the proton pumping mechanism. Their spatial relation to the chromophore is also discussed. At least two tyrosines are suggested to reside close to the retinal binding site. The reactive groups of the nitrated tyrosine-64 are speculated to be remote from the Schiff base and the active tyrosines but can possibly interact sterically with the ionone ring of the retinal.

Bacteriorhodopsins↗
PubMed1987

Remarriage after divorce: recent changes and demographic variations.

Using data from US Bureau of the Census publications from the decennial censuses and the Bureau's Current Population Reports, the authors analyze remarriage in the US. Among adults who had ended their 1st marriage in divorce, about 3/4 of the elderly men and 2/3 of the elderly women in both 1970 and 1980 were found to be remarried. However, the general decline in remarriage at the younger ages during the 1970s was accentuated among those under 35 years old. Although the proportion remarried among women with graduate school training was the smallest, that proportion declined less during the 1970s than for women in any other educational level. In both 1970 and 1980, the proportion remarried was positively correlated with personal income for men but negatively for women. An estimated 2/3 of those who end their 1st marriage in divorce will eventually remarry while they have young children living with them. During the lifetime of women in their 2nd marriage after their 1st marriage ended in divorce, only 1/3 of their children are born after remarriage, whereas 2/3 are born before their 2nd marriages. During the 1970s, the proportion of currently divorced adults living alone or sharing the homes of relatives diminished, while the proportion living as cohabitants outside marriage rose substantially. It appears as if both the divorce rate and the remarriage rate are approaching a period of relative stability.

Age Factors↗