Search PubMed⌕ Search

Biomedical subjects

Y C Lin

Publications and source records attributed to Y C Lin.

At least 325 records · Page 18Linked to original sources
PubMed1980

A simple preparation of N-phosphorylated lysine and arginine.

An improved specific synthesis of N-epsilon-phospholysine is described. Phosphorylation under basic conditions of the copper chelate of L-lysine with phosphorus oxychloride and subsequent removal of the copper ion affords N-epsilon-phospholysine as the sole phosphorylated product. Similar treatment of L-arginine yields N-omega-phosphoarginine as the sole product which is identical to that produced enzymatically.

Arginine↗
PubMed1980

Determination of catheter wall heat transfer in cardiac output measurement by thermodilution.

1. A model system of the thermal dilution technique was used to determine in vitro the loss of thermal indicator across different sizes of polyethylene catheters. 2. Thermal indicator loss (caloric gain by the indicator fluid or caloric loss by the catheter) per unit length of catheters (H/L) increased as a function of the outer radius (OR) of the catheters. Linear regression analysis gave the following equation: H/L=0.337OR+0.073 (r=0.88, P<0.05). 3. Thermal indicator loss per unit surface area (H/SA) decreased almost linearly with the following regression equation: H/SA=-1.860 OR+0.364 (r=0.97, P<0.97, P<0.01). 4. Thermal indicator loss per unit volume contained in the catheter (H/vol) decreased exponentially according to the following equation: H/vol =89.le-25.4(OR) (r=0.97, P<0.01). 5. This study indicates that there is a measurable loss of thermal indicator during injection corresponding to a loss between 9 and 16% (for a 11.5 cm length of PE 50 and PE 240) of the required calories for warming the injectate to 37 degrees C. Data is provided for correction of heat loss across the wall of a given length and diameter of polyethylene tubing.

Cardiac Catheterization↗
PubMed1980

Influence of temperature cycling on the production of aflatoxins B1 and G1 by Aspergillus parasiticus.

The effect of temperature cycling on the relative productions of aflatoxins B1 and G1 by Aspergillus parasiticus NRRL 2999 was studied. The cycling of temperature between 33 and 15 degrees C favored aflatoxin B1 accumulation, whereas cycling between 35 and 15 degrees C favored aflatoxin G1 production. Cultures subjected to temperature cycling between 33 and 25 degrees C at various time intervals changed the relative productions of aflatoxins B1 and G1 drastically. Results obtained with temperature cycling and yeast extract-sucrose medium with ethoxyquin to decrease aflatoxin G1 production suggest that the enzyme system responsible for the conversion of aflatoxin B1 to G1 might be more efficient at 25 degrees C than at 33 degrees C. The possible explanation of the effect of both constant and cycling temperatures on the relative accumulations of aflatoxins B1 and G2 might be through the control of the above enzyme system. The study also showed that greater than 57% of aflatoxin B1, greater than 47% of aflatoxin G1, and greater than 50% of total aflatoxins (B1 plus G1) were in the mycelium by day 10 under both constant and cyclic temperature conditions.

Aflatoxin B1↗
PubMed1979

A programmable calculator program for rapid logarithmic extrapolation, and calculation of mean transit time from an indicator-dilution curve.

Reconstruction of the primary indicator-dilution curve is accomplished by exponential curve-fit from a set of points obtained on the downslope of the curve. Curve-fit is simplified by requiring entry of indicator concentrations (Yi) only, where time increments (Xi) are made self-generating in the program. Similarly, calculation of mean transit time requires only the entries of Yi. Stored values supply the needed quantities for calculations of cardiac output and the central blood volume as defined by the injection and the sampling sites. The Texas Instrument TR 52 model hand-held programmable calculator is utilized in this program but it should be adaptable to other programmable calculators. The present program provides a procedure for rapid reconstruction of the primary indicator-dilution curve, and hence calculations of cardiac output, mean transit time and central blood volume.

Cardiac Output↗
PubMed1979

Factors affecting the physical performance of the rat in hyperbaric environments.

Experiments were designed to partition the effect of inspired oxygen tension (PIO2), gas density (rho), and ambient pressure (P) at rest and during exercise in rats. At rest oxygen uptake (VO2) was reduced by 19.5% (P less than 0.01) in 3 ATA air and by 32.1% (P less than 0.01) in 10 ATA air from 1 ATA air control of 29.3 +/- 1.21 (SE) ml/min.kg; there was no difference in VO2 between 1, 3, and 10 ATA He mixtures containing 20% O2. During exercise, VO2 was depressed by 36.2% (P less than 0.01) in 3 ATA air from 1 ATA air value of 55.3 +/- 3.23 ml/min.kg; VO2 was unaffected in 3 ATA He containing 20% O2 as compared to that of 46.5 +/- 2.43 ml/min.kg at 1 ATA He-O2 ambient. These VO2 values were compared to that obtained from normoxic ambients for separation of effects of elevated PIO2, P, and rho on VO2 at rest and during exercise. The effect of PIO2 was deduced by comparing VO2 in normoxic and hyperoxic He and N2 at a given P and rho. The density effect was obtained by comparing the VO2 in various densities at a given P and PIO2. The P effect was obtained by comparing the VO2 in various ambient pressures at a given rho and PIO2. Summation of the effects of P, rho, and PIO2 sufficiently approximates the changes in VO2 at rest. The same procedure underestimates the actually measured VO2 in all N2 ambients.

Air Pressure↗
PubMed1979

Is FSH required for maintenance of spermatogenesis in adult rats?

Administration of FSH antiserum to adult rats for 14 or 30 days had no or little effect on body, testis or accessory sex gland weights, androgen-binding protein, testosterone levels, germ cell numbers or fertility, thus indicating a relative insensitivity of the testis to withdrawal of FSH. Unlike immature rats, therefore, which do require FSH to initiate spermatogenesis, adult rats do not need this hormone to maintain spermatogenesis.

Age Factors↗
PubMed1979

Increased progesterone receptor concentrations in bladder lesions of estrogen-treated Syrian hamsters.

During studies of renal tumorigenesis induced by estrogen in Syrian hamsters, we have observed that about 15 to 20% of animals develop bladder lesions with an increased wet weight of tissue from 0.2 g to 0.4 to 1.7 g. Histological examination of the lesions showed a spectrum of changes from inflammatory reactions to squamous metaplasia and intense hyperplasia of the transitional epithelium. The concentration of progesterone-binding sites was increased in the bladders with lesions. No specific progesterone-binding sites could be detected in the cytosol of bladders from hamsters not treated with estrogen. The affinity constant for the progesterone-binding sites in cytosol from bladders with lesions was 10(9) M-1, the same as that reported for progesterone receptors in other target tissues for estrogen. The binding sites are specific for progesterone and are not competed for by 17 beta-estradiol, 5 alpha-dihydrotestosterone, or aldosterone.

Aldosterone↗
PubMed1979

Doppler detection of thresholds for decompression-induced venous gas emboli in the awake rat.

Awake, unrestrained rats with chronic implants of a Doppler probe on the vena cava, were saturated in a small plexiglass chamber at a maximum pressure (P1), rapidly decompressed to a predetermined pressure (P2) and then monitored for the presence of intravascular bubbles. If there were no indication of bubbles within 1 h, the decompression was considered bubble free. For each saturation pressure, an increasing pressure difference (deltaP = P1 - P2) was tried on each exposure until the threshold for bubble detection was found. The relationship deltaP = a P1 + b, where a and b are constants defining the threshold for bubble detection, was experimentally determined at pressures from 3-10 ATA. The depth-dependent linear relationship deltaP = 0.38P, + 1.29 (r = 0.97, P is less than 0.001) was found for first exposures and deltaP = 0.62 P1 + 0.16 (r = 0.99, p is less than 0.001) for repeat exposures. The chronic Doppler preparation allows a more sensitive threshold determination than past methods for small animals and also allows repeat pressure exposures without the effects of a severe decompression stress.

Animals↗
PubMed1979

Absence of antiarrhythmic effects of helium in patients with spontaneous premature ventricular beats at rest.

Six patients with spontaneously occurring arrhythmias were studied to assess the antiarrhythmic properties of helium. The patients were divided into two subgroups breathing air, helium-oxygen (heliox), and nitrogen-oxygen (nitrox) in an alternating sequence during successive 20-min periods under continuous ECG surveillance at rest. There were no significant reductions in spontaneously occurring premature ventricular beats while breathing heliox, compared to breathing air of nitrox. Alternating the breathing gases in this manner caused no change in plasma concentration of electrolytes or in activity of serum glutamic-oxaloacetic transaminase or lactic acid dehydrogenase. We conclude that helium does not affect spontaneously occurring chronic premature ventricular beats in conscious resting man when it is breathed for a period of up to 20 min.

Adult↗
PubMed1978

Effect of carpaine, a papaya alkaloid, on the circulatory function in the rat.

Carpaine is one of the major components of alkaloid of papaya leaves. Circulatory effects of carpaine were studied in Wistar male rats weighing 314 +/- 13 g, under pentabarbital (30 mg/kg) anesthesia. Increasing dosages of carpaine from 0.5 mg/kg to 2.0 mg/kg resulted in progressive decrease in systolic, diastolic, and mean arterial blood pressure. Selective autonomic nervous blockade with atropine sulfate (1 mg/kg) or propranolol hydrochloride (8 mg/kg) did not alter the circulatory response to carpaine. Carpaine, 2 mg/kg, reduced cardiac output, stroke volume, stroke work, and cardiac power, but the calculated total peripheral resistance remained unchanged. It is concluded from these results that carpaine affects the myocardium directly. The effects of carpaine may be related to its macrocyclic dilactone structure, a possible cation chelating structure.

Alkaloids↗
PubMed1977

Phosphorylation of nuclear proteins in rat regenerating liver.

In studies of the phosphorylated proteins in rat liver and Walker-256, it was established that the ratio of various fractions of P-N linkages to P-O linkages varies from 0.6 to 3.1. In rat regenerating liver nuclei, the ratio of P-N and P-O varies with time after partial hepatectomy. Using [3H]-lysine and 32Pi, it is shown that phosphoryllysine forms in some new and, presumably, some preexisting H1 molecules. Using [3H]histidine and 32Pi, it is shown that phosphohistidine forms exclusively in preexisting H4. The half-life of H4 phosphohistidine appears to be about 2 h.

Animals↗
PubMed1977

Studies on Thermoactinomyces sp. TM9208. I. Description of the strain.

A strain of Thermoactinomyces sp., TM9208, isolated from a soil sample in the Taipei area showed antagonistic activity to Gram positive bacteria but not to the Gram negative on the potato extract agar plate by the cross streaking method. The strain showed strong starch hydrolysis, beta type of hemolysis, brownish yellow growth on the potato extract agar and green on the nutrient agar. Its aerial mycelium, white to grayish white, was long and straight with short branches. The spores are single and have smooth surface. It is a good utilizer of starch, maltose and cellobiose as carbon source, but utilizes dulcitol, salicin, sucrose, rhamnose and sorbitol poorly.

Bacteria↗
PubMed1977

Effects of cordacin on lymphocyte activity in vitro.

The effects of cordacin on lymphocyte activity were studied with two parameters in vitro. The cordacin inhibited T lymphocyte E rosette formation by 93% at the concentration of 1,000 microgram/ml and tritiated-thymidine incorporation into PHA-transformed lymphocytes by 66% at the concentration of 10 microgram/ml. The implication of these results on replicating leukemic as well as normal cells is discussed.

Antineoplastic Agents↗