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Biomedical subjects

C Y Lin

Publications and source records attributed to C Y Lin.

At least 433 records · Page 24Linked to original sources
PubMed1983

Effect of specific dietary fatty acids on lipogenesis in the livers and mammary glands of lactating mice.

The effects of linoleic, linolenic and columbinic acids fed as 4% of a high carbohydrate (50% glucose) diet on the activities and the amounts of several enzymes associated with fatty acid synthesis in livers and mammary glands of lactating mice were compared with those for stearic and oleic acids. Fatty acid synthesis, measured in vivo, was significantly lower in livers of mice ingesting all 3 polyunsaturated fatty acids (PUFA), whereas in mammary glands synthesis was lower only in mice receiving columbinic acid. The activities of fatty acid synthetase (FAS) and acetyl CoA carboxylase were significantly reduced in liver by all 3 PUFA, as wee activities of glucose-6-phosphate dehydrogenase, malic enzyme (ME) and citrate cleavage enzyme (CCE), also associated with lipogenesis. In mammary gland, on the other hand, the activities of these enzymes were unaffected by dietary PUFA. The tissue contents of FAS, ME and CCE, measured by rocket immunoelectrophoresis, were found to be significantly reduced in liver by linoleate, linolenate and columbinate but were not significantly altered in mammary gland. The decrease in hepatic lipogenesis observed was principally due to a decrease in the amounts of these enzymes induced by the dietary PUFA but the inhibition in mammary gland caused by columbinate could not be accounted for by a reduction in enzyme contents and therefore may be due to allosteric effects which occur when fatty acid synthesis is measured with 3H2O. The fatty acid composition in liver and mammary gland of dams and in liver and kidney of pups completely reflected dietary fatty acids. Columbinate made up ca. 20% of the total fatty acids in both tissues of the columbinic acid-fed mice and ca. 15% in the pup tissues. This suggests that columbinate is incorporated into milk lipids of dams and is easily absorbed by pups. The elevated ratios of 16/16:1 and 18/18:1 in liver and mammary gland of dams and liver and kidney of the pups from dams fed linoleate, linolenate and columbinate suggest that each of these polyunsaturated fatty acids in the diet can inhibit the activity of delta 9 desaturase.

Animals↗
PubMed1983

Cardiovascular responses to PEEP and CPAP following repair of complicated congenital heart defects.

Fourteen infants and children ranging in age from 7 months to 8 years were studied in a hemodynamically stable condition following repair of various heart defects. Changes in cardiac index, stroke index, heart rate, systemic vascular resistance, mean arterial pressure, and central venous pressure were evaluated at levels of 0, 5, and 10 cm H2O using positive end-expiratory pressure (PEEP) in 14 patients and continuous positive airway pressure (CPAP) in 3 patients. No significant changes were found in any of the measurements taken at the different levels.

Blood Pressure↗
PubMed1983

Fractionation of nucleoli from auxin-treated soybean hypocotyl into nucleolar chromatin and preribosomal particles.

Nucleoli from auxin-treated tissues (Glycine max L. var Wayne or Kaoshiung No. 3) were isolated and purified by Percoll density gradient centrifugation. There was a 2.1-fold increase in RNA and a 2.8-fold increase in protein after a 24-h auxin treatment per unit nucleolar DNA. More than 150 acid-soluble protein spots were associated with the auxin-treated nucleoli on two dimensional (2-D) gel electropherograms.Nucleoli from auxin-treated tissue were fractionated by suspension in 20 millimolar dithiothreitol at room temperature for 20 minutes into two distinct fractions referred to as the nucleolar chromatin and preribosomal particle fractions. The DNA:RNA:protein ratio of the chromatin fraction was 1:2.5:14. Most of RNA polymerase 1 activity and nucleolar DNA recovered in this fraction. The acid-soluble proteins in the chromatin were resolved into 32 protein spots on 2-D gel electropherogram. The most abundant spots were identified as histones.The nucleolar preribosomal particle fraction had a DNA:RNA:protein ratio of 1:24:102 and contained only trace amounts of RNA polymerase 1 activity and only 10 per cent of the nucleolar DNA. Acid-soluble proteins associated with these particles were resolved into 78 protein spots; 72 of these (acid-soluble) protein spots corresponded in 2-D gel electrophoresis to 80S cytoplasmic ribosomal proteins. Some 15 protein spots found in 80S ribosomal proteins were absent in the preribosomal particles. It seems reasonable, based on these data, that the enlargement of nucleoli after auxin treatment is primarily due to the large increase in ribosomal proteins and rRNA which accumulate and assemble in the nucleoli in the form of preribosomal particles.

Journal Article↗
PubMed1983

Biochemical changes in rat liver after 18.5 days of spaceflight.

The effect of "weightlessness" on liver metabolism was examined using tissue from rats flown in earth orbit for 18.5 days aboard the Soviet Cosmos 936 biosatellite. Changes in the activities of certain carbohydrate and lipid enzymes were noted. Of the 28 hepatic enzyme activities assayed, two, palmitoyl-CoA desaturase and lactate dehydrogenase, increased, whereas five, glycogen phosphorylase, 6-phosphogluconate dehydrogenase, both acyltransferases which act on alpha-glycerolphosphate and diglycerides, and aconitate hydratase decreased. The remaining enzyme activities measured were unchanged. In addition, increased levels of liver glycogen and palmitoleate were noted which probably resulted from the lowered glycogen phosphorylase and increased palmitoyl-CoA desaturase activities, respectively, in those animals that experienced weightlessness. These changes caused by weightlessness were transient since all of the aforementioned alterations returned to normal values when measured in the livers of other rats which had flown in the biosatellite 25 days after recovery.

Aconitate Hydratase↗
PubMed1983

Measles and acute glomerulonephritis.

A 5-year-old boy had transient glomerulonephritis following measles infection. Serologic studies at the early onset of the disease showed decrease of serum C3, C4, and Clq levels with normal serum properdin factor B. Renal glomerular histology revealed a mild acute proliferative glomerulonephritis. Measles virus antigen, C3, C4, and immunoglobulin G (IgG) were demonstrated in the glomerulus, suggesting an immune complex deposition. Ultrastructurally, subepithelial, intramembranous, and subendothelial electron-dense deposits were noted, suggesting a postinfectious immune complex glomerulonephritis. It is suggested that the measles virus antibody complexes are deposited in the glomerulus and activate the classic pathway of complement, leading to a self-limited glomerulonephritis.

Antigen-Antibody Complex↗
PubMed1983

Elevation of cAMP levels in cerebrospinal fluid of patients with neonatal meningitis.

The cyclic 3',5'-adenosine monophosphate (cAMP) concentrations in the cerebrospinal fluid of 20 children with neonatal bacterial meningitis and aseptic meningitis were measured by radioimmunoassay method. The cAMP levels were found to be significantly elevated above control levels (P less than .01) during the acute phase in most of the patients. In the convalescent stage the cAMP concentration was decreased but levels remained significantly elevated (P less than .01) in patients with complications. During the acute phase, the cAMP levels were higher in neonatal bacterial meningitis than in aseptic meningitis (P less than .01). The results suggest that cAMP is a sensitive indicator of transient cellular metabolic disturbance in the brain and may be used to monitor the course of neonatal meningitis.

Bacterial Infections↗
PubMed1982

In vitro determination of accuracy of cardiac output measurements by thermal dilution.

The accuracy of cardiac output (C.O.) measurements by the thermodilution method was evaluated in an in vitro model within a flow range from 1 to 5 liters/min. For C.O. determinations, a 5F Swan-Ganz balloon-tipped thermodilution catheter and a 9520 Edwards computer were used. We made 420 measurements at known flow rates. In serial determinations, we achieved an overall accuracy of 86 to 93% compared to the reference flow; for single determinations, the accuracy ranged from 75 to 85%. The indicator volume (3, 5, or 10 cc) had no influence on the results. The thermodilution determinations at each flow rate were reproducible at between 2.5 and 8.5%. There was no difference in accuracy or reproducibility when ice-cold or room temperature saline was used. Caution in the interpretation of single C.O. determinations in low-flow states, i.e., in pediatric patients, is recommended.

Cardiac Catheterization↗
PubMed1982

Mechanism for shifting the phase of a circadian rhythm by serotonin: involvement of cAMP.

Serotonin (5-hydroxytryptamine, 5-HT) shifts the phase of the circadian rhythm in the eye of Aplysia. We have examined the role of cAMP in mediating the effects of 5-HT on the rhythm. The phase shifts produced by 5-HT are mimicked by treatments that should increase intracellular levels of cAMP. An analogue of cAMP-8-benzylthio-cAMP, advanced and delayed the rhythm at phases in which 5-HT had similar effects on the rhythm. In addition, two phosphodiesterase inhibitors, Ro-20-1724 and papaverine, caused advance phase shifts where 5-HT advances the rhythm. The phosphodiesterase inhibitors Ro-20-1724 and 3-isobutyl-1-methylxanthine each potentiated the effect of subthreshold doses of 5-HT on the rhythm. The effects of 5-HT and 8-benzylthio-cAMP on the rhythm were nonadditive, indicating that 5-HT and 8-benzylthio-cAMP affect the rhythm through a common pathway. Finally, 5-HT produced large changes (13-fold) in the levels of cAMP in the eye. These results indicate that cAMP mediates the effect of 5-HT on the rhythm. There are two possible roles for cAMP in the circadian system. Either the cAMP system is an intracellular step in an entrainment pathway or it is part of the biological clock. Because 5-HT, 8-benzylthio-cAMP, and three phosphodiesterase inhibitors inhibit impulses from the eye, cAMP may also mediate the inhibition produced by 5-HT, or it might be involved in regulating the frequency of spontaneous impulses throughout the day.

Action Potentials↗
PubMed1982

Treatment of chronic mucocutaneous candidiasis with 5-fluorocytosine.

A four-year-old girl with chronic mucocutaneous candidiasis (CMC) and an immunologic deficiency syndrome was studied in detail over a period of two years. Her lymphocytes neither produced migratory inhibitory factor nor responded consistently with an increased 3H-thymidine uptake when placed in tissue culture medium with candida antigen. The serum IgE was increased. No autoantibody was demonstrated in the patient's serum and she did not have nay kind of endocrine disorder. Eradication of the candida infection with 5-fluorocytosine, although resulting in marked clinical improvement, did not alter the immunologic abnormalities.

Antibody Formation↗
PubMed1982

Serial studies of circulating immune complexes in poststreptococcal glomerulonephritis.

Levels of circulating immune complexes were determined in 30 children who suffered from acute poststreptococcal glomerulonephritis. The study was started in the acute phase of the disease and continued for one year. Raji cell radioimmune assay was used for the detection of immune complexes. The patients had significantly elevated levels of immune complexes during the acute phase, especially in the first three days after the onset of hematuria. Six months later the levels of immune complexes declined to slightly elevated levels, and nine months after the initial attack, no immune complexes were detectable. However, the patients who had persistent hematuria and proteinuria continued to have detectable immune complexes during this time.

Acute Disease↗
PubMed1981

The effects of space flight on some rat liver enzymes regulating carbohydrate and lipid metabolism.

We have examined, in the livers of rats carried aboard the Cosmos 936 biosatellite, the activities of about 30 enzymes concerned with carbohydrate and lipid metabolism. In addition to the enzyme studies, the levels of glycogen and of the individual fatty acids in hepatic lipids were determined. Livers from flight and ground control rats at recovery (R0) and 25 days after recovery (R25) were used for these analyses. For all parameters measured, the most meaningful comparisons are those made between flight stationary (FS) and flight centrifuged (FC) animals at RQ. When these two groups of flight rats were compared at R0, statistically significant decreases in the activity levels of glycogen phosphorylase, alpha-glycerol phosphate acyl transferase, diglyceride acyl transferase, aconitase and 6-phosphogluconate dehydrogenase and an increase in the palmitoyl CoA desaturase were noted in the weightless group (FS). The significance of these findings was strengthened by the fact that all enzyme activities showing alterations at R0 returned to normal 25 days postflight. When liver glycogen and total fatty acids of the two sets of flight animals were determined, significant differences that could be attributed to reduced gravity were observed. The weightless group (FS) at R0 contained, on the average, more than twice the amount of glycogen than did the centrifuged controls (FC) and a remarkable shift in the ratio of palmitate to palmitoleate was noted. These metabolic alterations, both in enzyme levels and in hepatic constituents, appear to be characteristic of the weightless condition. Our data seem to justify the conclusion that centrifugation during flight is equivalent to terrestrial gravity.

Animals↗
PubMed1981

Heat shock proteins of higher plants.

The pattern of protein synthesis changes rapidly and dramatically when the growth temperature of soybean seedling tissue is increased from 28 degrees C (normal) to about 40 degrees C (heat shock). The synthesis of normal proteins is greatly decreased and a new set of proteins, "heat shock proteins," is induced. The heat shock proteins of soybean consist of 10 new bands on one-dimensional NaDodSO(4) gels; a more complex pattern is observed on two-dimensional gels. When the tissue is returned to 28 degrees C after 4 hr at 40 degrees C, there is progressive decline in the synthesis of heat shock proteins and reappearance of a normal pattern of synthesis by 3 or 4 hr. In vitro translation of poly(A)(+)RNAs isolated from tissues grown at 28 and 40 degrees C shows that the heat shock proteins are translated from a new set of mRNAs induced at 40 degrees C; furthermore, the abundant class mRNAs for many of the normal proteins persist even though they are translated weakly (or not at all) in vivo at 40 or 42.5 degrees C. The heat shock response in soybean appears similar to the much-studied heat shock phenomenon in Drosophila.

Journal Article↗
PubMed1981

Effect of estrogen on metabolism and enzyme activities of mammary adenocarcinoma R3230AC in Fischer rats.

Metabolic characteristics and enzyme activities are reported for a variant line of R3230AC tumor, a long-established, transplantable mammary adenocarcinoma in the Fischer rat. Lipogenic enzyme activities from the variant tumor are generally lower than those reported for early generations of this tumor. In addition, the proportion of the medium-chain-length fatty acids in the lipids of this variant line is lower. In the variant tumor, estrogen treatment of host animals results in a reduction of fatty acid synthesis from both acetate and glucose. The response of the variant tumor to estrogen treatment is similar to that for the normal gland in a virgin rat in that lipogenic enzyme activities are lowered in both normal and neoplastic tissues. These enzymatic activities in early generations of tumor R3230AC were similar to those observed in mammary glands from lactating rather than virgin rats. Since the variant tumor still responds to estrogen treatment by a reduced growth rate, we have inferred that, although it undergoes the same structural differentiation observed in earlier generations, the variant tumor line no longer shows certain biochemical changes associated with the lactational state in the normal gland.

Adenocarcinoma↗